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Carbon catabolite repression in Bacillus subtilis: quantitative analysis of repression exerted by different carbon sources

Abstract (Expand)

In many bacteria glucose is the preferred carbon source and represses the utilization of secondary substrates. In Bacillus subtilis, this carbon catabolite repression (CCR) is achieved by the global … transcription regulator CcpA, whose activity is triggered by the availability of its phosphorylated cofactors, HPr(Ser46-P) and Crh(Ser46-P). Phosphorylation of these proteins is catalyzed by the metabolite-controlled kinase HPrK/P. Recent studies have focused on glucose as a repressing substrate. Here, we show that many carbohydrates cause CCR. The substrates form a hierarchy in their ability to exert repression via the CcpA-mediated CCR pathway. Of the two cofactors, HPr is sufficient for complete CCR. In contrast, Crh cannot substitute for HPr on substrates that cause a strong repression. Determination of the phosphorylation state of HPr in vivo revealed a correlation between the strength of repression and the degree of phosphorylation of HPr at Ser46. Sugars transported by the phosphotransferase system (PTS) cause the strongest repression. However, the phosphorylation state of HPr at its His15 residue and PTS transport activity have no impact on the global CCR mechanism, which is a major difference compared to the mechanism operative in Escherichia coli. Our data suggest that the hierarchy in CCR exerted by the different substrates is exclusively determined by the activity of HPrK/P.

Authors: Kalpana D Singh, Matthias H Schmalisch, , Boris Görke

Date Published: 29th Aug 2008

Publication Type: Not specified

Carbon catabolite repression in bacteria: many ways to make the most out of nutrients

Abstract (Expand)

Most bacteria can selectively use substrates from a mixture of different carbon sources. The presence of preferred carbon sources prevents the expression, and often also the activity, of catabolic … systems that enable the use of secondary substrates. This regulation, called carbon catabolite repression (CCR), can be achieved by different regulatory mechanisms, including transcription activation and repression and control of translation by an RNA-binding protein, in different bacteria. Moreover, CCR regulates the expression of virulence factors in many pathogenic bacteria. In this Review, we discuss the most recent findings on the different mechanisms that have evolved to allow bacteria to use carbon sources in a hierarchical manner.

Authors: Boris Görke,

Date Published: 17th Jul 2008

Publication Type: Not specified

Carbon source control of the phosphorylation state of the Bacillus subtilis carbon-flux regulator Crh in vivo

Abstract (Expand)

Bacillus subtilis possesses carbon-flux regulating histidine protein (Crh), a paralog of the histidine protein (HPr) of the phosphotransferase system (PTS). Like HPr, Crh becomes (de)phosphorylated in … vitro at residue Ser46 by the metabolite-controlled HPr kinase/phosphorylase HPrK/P. Depending on its phosphorylation state, Crh exerts regulatory functions in connection with carbohydrate metabolism. So far, knowledge on phosphorylation of Crh in vivo has been limited and derived from indirect evidence. Here, we studied the dynamics of Crh phosphorylation directly by non-denaturing gel electrophoresis followed by Western analysis. The results confirm that HPrK/P is the single kinase catalyzing phosphorylation of Crh in vivo. Accordingly, phosphorylation of Crh is triggered by the carbon source as observed previously for HPr, but with some differences. Phosphorylation of both proteins occurred during exponential growth and disappeared upon exhaustion of the carbon source. During exponential growth, ~80% of the Crh molecules were phosphorylated when cells utilized a preferred carbon source. The reverse distribution, i.e. around 20% of Crh molecules phosphorylated, was obtained upon utilization of less favorable substrates. This clear-cut classification of the substrates into two groups has not previously been observed for HPr(Ser)~P formation. The likely reason for this difference is the additional PTS-dependent phosphorylation of HPr at His15, which limits accumulation of HPr(Ser)~P.

Authors: Jens J Landmann, Susanne Werner, , , Boris Görke

Date Published: 28th Nov 2011

Publication Type: Not specified

Cardiac PI3K p110alpha attenuation delays aging and extends lifespan.

Abstract (Expand)

Phosphoinositide 3-kinase (PI3K) is a key component of the insulin signaling pathway that controls cellular me-tabolism and growth. Loss-of-function mutations in PI3K signaling and other downstream … effectors of the insulin signaling pathway extend the lifespan of various model organisms. However, the pro-longevity effect appears to be sex-specific and young mice with reduced PI3K signaling have increased risk of cardiac disease. Hence, it remains elusive as to whether PI3K inhibition is a valid strategy to delay aging and extend healthspan in humans. We recently demonstrated that reduced PI3K activity in cardiomyocytes delays cardiac growth, causing subnormal contractility and cardiopulmonary functional capacity, as well as increased risk of mortality at young age. In stark contrast, in aged mice, experi-mental attenuation of PI3K signaling reduced the age-dependent decline in cardiac function and extended maximal lifespan, suggesting a biphasic effect of PI3K on cardiac health and survival. The cardiac anti-aging effects of reduced PI3K activity coincided with enhanced oxida-tive phosphorylation and required increased autophagic flux. In humans, explanted failing hearts showed in-creased PI3K signaling, as indicated by increased phos-phorylation of the serine/threonine-protein kinase AKT. Hence, late-life cardiac-specific targeting of PI3K might have a therapeutic potential in cardiac aging and related diseases.

Authors: M. Abdellatif, T. Eisenberg, A. M. Heberle, K. Thedieck, G. Kroemer, S. Sedej

Date Published: 30th Nov 2022

Publication Type: Journal

Cause and cure of sloppiness in ordinary differential equation models

Abstract (Expand)

Data-based mathematical modeling of biochemical reaction networks, e.g., by nonlinear ordinary differential equation (ODE) models, has been successfully applied. In this context, parameter estimation … and uncertainty analysis is a major task in order to assess the quality of the description of the system by the model. Recently, a broadened eigenvalue spectrum of the Hessian matrix of the objective function covering orders of magnitudes was observed and has been termed as sloppiness. In this work, we investigate the origin of sloppiness from structures in the sensitivity matrix arising from the properties of the model topology and the experimental design. Furthermore, we present strategies using optimal experimental design methods in order to circumvent the sloppiness issue and present nonsloppy designs for a benchmark model.

Authors: Christian Tönsing, Jens Timmer, Clemens Kreutz

Date Published: 1st Aug 2014

Publication Type: Not specified

CcpA forms complexes with CodY and RpoA in Bacillus subtilis

Abstract (Expand)

The Bacillus subtilis catabolite control protein A (CcpA) is a global transcriptional regulator which is controlled by interactions with the phosphoproteins HPrSer46P and CrhP and with low molecular … weight effectors depending on the availability of preferred carbon sources like glucose. Distinct point mutations in CcpA abolish regulation of some but not all target genes suggesting additional interactions of CcpA. Therefore, in vivo crosslinking and mass spectrometry were applied to identify CcpA complexes active in repression and activation. To compensate for the excess of promoters only repressed by CcpA, this experiment was accomplished with cells with multiple copies of the activated ackA promoter. Among the identified proteins HPr, RNA polymerase (RNAP) subunits and the global regulator CodY were observed. Bacterial two-hybrid assays combining each RNAP subunit with CcpA localized CcpA binding at the α-subunit (RpoA). In vivo crosslinking combined with immunoblot analyses revealed CcpA-RpoA complexes in cultures with or without glucose whereas CcpA-HPr and CcpA-CodY complexes occurred only or predominantly in cultures with glucose. Surface plasmon resonance (SPR) analyses confirmed binding of CcpA to the N- (αNTD) and C-terminal domains (αCTD) of RpoA as well as to CodY. Furthermore, interactions of CodY with the αNTD and the αCTD were detected by SPR. The K(D) values of complexes of CcpA or CodY with the αNTD or the αCTD are between 5 and 8μM. CcpA and CodY form a loose complex with a K(D) of 60μM. These data were combined to propose a model for a transcription initiation complex at the ackA promoter.

Authors: Andrea Wünsche, Elke Hammer, , , Andreas Burkovski, ,

Date Published: 20th Apr 2012

Publication Type: Not specified

Cell size and morphological properties of yeast Saccharomyces cerevisiae in relation to growth temperature

Abstract (Expand)

Cell volume is an important parameter for modelling cellular processes. Temperature-induced variability of cellular size, volume, intracellular granularity, a fraction of budding cells of yeast … Saccharomyces cerevisiae CEN.PK 113–7D (in anaerobic glucose unlimited batch cultures) were measured by flow cytometry and matched with the performance of the biomass growth (maximal specific growth rate (μmax), specific rate of glucose consumption, the rate of maintenance, biomass yield on glucose). The critical diameter of single cells was 7.94 μm and it is invariant at growth temperatures above 18.5°C. Below 18.5°C, it exponentially increases up to 10.2 μm. The size of the bud linearly depends on μmax, and it is between 50% at 5°C and 90% at 31°C of the averaged single cell. The intracellular granularity (side scatter channel (SSC)-index) negatively depends on μmax. There are two temperature regions (5–31°C vs. 33–40°C) where the relationship between SSC-index and various cellular parameters differ significantly. In supraoptimal temperature range (33–40°C), cells are less granulated perhaps due to a higher rate of the maintenance. There is temperature dependent passage through the checkpoints in the cell cycle which influences the μmax. The results point to the existence of two different morphological states of yeasts in these different temperature regions.

Authors: Maksim Zakhartsev, Matthias Reuss

Date Published: 26th Apr 2018

Publication Type: Not specified

CellPublisher: a web platform for the intuitive visualization and sharing of metabolic, signalling and regulatory pathways

Abstract (Expand)

Systems biology relies increasingly on collaborations between several groups with different expertise. Therefore, the systems biology community is adopting standards that allow effective communication … of concepts, as well as transmission and processing of pathway information. The Systems Biology Graphical Notation (SBGN) is a graphical language for biological pathways that has both a biological as well as a computational meaning. The program CellDesigner allows the codification of biological phenomena in an SBGN compliant form. CellPublisher is a web server that allows the conversion of CellDesigner files to web-based navigatable diagrams based on the user interface of Google maps. Thus, CellPublisher complements CellDesigner by facilitating the understanding of complex diagrams and by providing the possibility to share any CellDesigner diagram online with collaborators and get their feedback. Due to the intuitive interface of the online diagrams, CellPublisher serves as a basis for discovery of novel properties of the modelled networks.

Authors: , Christoph R Lammers, Raphael Michna,

Date Published: 14th Oct 2010

Publication Type: Not specified

Cellular Adjustments of Bacillus subtilis and Other Bacilli to Fluctuating Salinities

Abstract

Not specified

Authors: Marco Pittelkow,

Date Published: 2011

Publication Type: Not specified

Cellular Immune Responses to Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) Infection in Senescent BALB/c Mice: CD4+ T Cells Are Important in Control of SARS-CoV Infection

Abstract

Not specified

Authors: J. Chen, Y. F. Lau, E. W. Lamirande, C. D. Paddock, J. H. Bartlett, S. R. Zaki, K. Subbarao

Date Published: 11th Jan 2010

Publication Type: Journal

Cellular localization of choline-utilization proteins in Streptococcus pneumoniae using novel fluorescent reporter systems

Abstract (Expand)

The molecular mechanisms underlying cell growth, cell division and pathogenesis in Streptococcus pneumoniae are still not fully understood. Single-cell methodologies are potentially of great value to … investigate S. pneumoniae cell biology. Here, we report the construction of novel plasmids for single and double cross-over integration of functional fusions to the gene encoding a fast folding variant of the green fluorescent protein (GFP) into the S. pneumoniae chromosome. We have also established a zinc-inducible system for the fine control of gfp-fusion gene expression and for protein depletion experiments in S. pneumoniae. Using this novel single cell toolkit, we have examined the cellular localization of the proteins involved in the essential process of choline decoration of S. pneumoniae teichoic acid. GFP fusions to LicA and LicC, enzymes involved in the activation of choline, showed a cytoplasmic distribution, as predicted from their primary sequences. A GFP fusion to the choline importer protein LicB showed clear membrane localization. GFP fusions to LicD1 and LicD2, enzymes responsible for loading of teichoic acid subunits with choline, are also membrane-associated, even though both proteins lack any obvious membrane spanning domain. These results indicate that the decoration of teichoic acid by the LicD enzymes is a membrane-associated process presumably occurring at lipid-linked teichoic acid precursors.

Authors: Alice Eberhardt, Ling J Wu, Jeff Errington, Waldemar Vollmer,

Date Published: 8th Sep 2009

Publication Type: Not specified

Central role of the RNA polymerase trigger loop in intrinsic RNA hydrolysis

Abstract (Expand)

The active center of RNA polymerase can hydrolyze phosphodiester bonds in nascent RNA, a reaction thought to be important for proofreading of transcription. The reaction proceeds via a general two … Mg(2+) mechanism and is assisted by the 3' end nucleotide of the transcript. Here, by using Thermus aquaticus RNA polymerase, we show that the reaction also requires the flexible domain of the active center, the trigger loop (TL). We show that the invariant histidine (beta' His1242) of the TL is essential for hydrolysis/proofreading and participates in the reaction in two distinct ways: by positioning the 3' end nucleotide of the transcript that assists catalysis and/or by directly participating in the reaction as a general base. We also show that participation of the beta' His1242 of the TL in phosphodiester bond hydrolysis does not depend on the extent of elongation complex backtracking. We obtained similar results with Escherichia coli RNA polymerase, indicating that the function of the TL in phosphodiester bond hydrolysis is conserved among bacteria.

Authors: Yulia Yuzenkova,

Date Published: 1st Jun 2010

Publication Type: Not specified

Chapter 6. Regulation of antibiotic production by bacterial hormones

Abstract (Expand)

Antibiotic production is regulated by numerous signals, including the so-called bacterial hormones found in antibiotic producing organisms such as Streptomyces. These signals, the gamma-butyrolactones, … are produced in very small quantities, which has hindered their structural elucidation and made it difficult to assess whether they are being produced. In this chapter, we describe a rapid small-scale extraction method from either solid or liquid cultures in scales of one plate or 50 ml of medium. Also described is a bioassay to detect the gamma-butyrolactones by determining either the production of pigmented antibiotic of Streptomyces coelicolor or kanamycin resistant growth on addition of the gamma-butyrolactones. We also describe some insights into the identification of the gamma-butyrolactone receptor and its targets and also the gel retardation conditions with three differently labeled probes.

Authors: Nai-Hua Hsiao, Marco Gottelt,

Date Published: 21st Apr 2009

Publication Type: Not specified

Characterization of E. coli MG1655 and frdA and sdhC mutants at various aerobiosis levels

Abstract

Not specified

Authors: , S. Frixel, ,

Date Published: 1st Jun 2011

Publication Type: Not specified

Characterization of the Weimberg Pathway in Caulobacter crescentus

Abstract (Expand)

Caulobacter crescentus is a gram-negative bacterium that can utilize xylose as a substrate using the Weimberg pathway, which converts xylose to α-ketoglutarate in five steps without carbon loss. This … is an interesting pathway for heterologous expression in other organisms in order to enable xylose utilization in biorefinery processes. C. crescentus was grown on xylose, arabinose and glucose, and maximum specific growth rates determined for the three substrates were 0.11 h−1, 0.05 h−1, and 0.15 h−1 respectively. Growth was found to be significantly inhibited at sugar concentration of 20 g L−1, shown primarily by an increased lag phase. Enzyme activity assays showed that the Weimberg pathway was active in cells grown, not only on xylose but also on arabinose. No activity was found for growth on glucose. Furthermore, substantial amounts of α-ketoglutarate—up to a yield of 0.4 g g−1—was excreted during growth on xylose, but no other extracellular intermediates in the Weimberg pathway were detected during growth on xylose. Apparently, C. crescentus is not well adapted for efficient growth on high xylose levels, and responds by an extended lag phase and secretion of α-ketoglutarate.

Authors: Henrik Almqvist, Sara Jonsdottir Glaser, Celina Tufvegren, Lisa Wasserstrom, Gunnar Lidén

Date Published: 1st Jun 2018

Publication Type: Not specified

Chemical identification and indexing in full-text articles: an overview of the NLM-Chem track at BioCreative VII

Abstract (Expand)

Abstract The BioCreative National Library of Medicine (NLM)-Chem track calls for a community effort to fine-tune automated recognition of chemical names in the biomedical literature. Chemicals are one …erature. Chemicals are one of the most searched biomedical entities in PubMed, and—as highlighted during the coronavirus disease 2019 pandemic—their identification may significantly advance research in multiple biomedical subfields. While previous community challenges focused on identifying chemical names mentioned in titles and abstracts, the full text contains valuable additional detail. We, therefore, organized the BioCreative NLM-Chem track as a community effort to address automated chemical entity recognition in full-text articles. The track consisted of two tasks: (i) chemical identification and (ii) chemical indexing. The chemical identification task required predicting all chemicals mentioned in recently published full-text articles, both span [i.e. named entity recognition (NER)] and normalization (i.e. entity linking), using Medical Subject Headings (MeSH). The chemical indexing task required identifying which chemicals reflect topics for each article and should therefore appear in the listing of MeSH terms for the document in the MEDLINE article indexing. This manuscript summarizes the BioCreative NLM-Chem track and post-challenge experiments. We received a total of 85 submissions from 17 teams worldwide. The highest performance achieved for the chemical identification task was 0.8672 F-score (0.8759 precision and 0.8587 recall) for strict NER performance and 0.8136 F-score (0.8621 precision and 0.7702 recall) for strict normalization performance. The highest performance achieved for the chemical indexing task was 0.6073 F-score (0.7417 precision and 0.5141 recall). This community challenge demonstrated that (i) the current substantial achievements in deep learning technologies can be utilized to improve automated prediction accuracy further and (ii) the chemical indexing task is substantially more challenging. We look forward to further developing biomedical text–mining methods to respond to the rapid growth of biomedical literature. The NLM-Chem track dataset and other challenge materials are publicly available at https://ftp.ncbi.nlm.nih.gov/pub/lu/BC7-NLM-Chem-track/. Database URL https://ftp.ncbi.nlm.nih.gov/pub/lu/BC7-NLM-Chem-track/

Authors: Robert Leaman, Rezarta Islamaj, Virginia Adams, Mohammed A Alliheedi, João Rafael Almeida, Rui Antunes, Robert Bevan, Yung-Chun Chang, Arslan Erdengasileng, Matthew Hodgskiss, Ryuki Ida, Hyunjae Kim, Keqiao Li, Robert E Mercer, Lukrécia Mertová, Ghadeer Mobasher, Hoo-Chang Shin, Mujeen Sung, Tomoki Tsujimura, Wen-Chao Yeh, Zhiyong Lu

Date Published: 2023

Publication Type: Journal

Chemoenzymatic Hydroxymethylation of Carboxylic Acids by Tandem Stereodivergent Biocatalytic Aldol Reaction and Chemical Decarboxylation

Abstract (Expand)

Chiral 2-substituted 3-hydroxycarboxylic acid derivatives are valuable building blocks for the preparation of naturally occurring and synthetic biologically active molecules. Current methodologies for … the preparation of these compounds are still limited for large-scale production due to the high costs, limited microbial strains, low yields, difficult downstream processing, and limited range of structures. We report an effective chemoenzymatic method for the synthesis of enantiomerically pure 2 substituted 3 hydroxycarboxylic esters. The strategy comprises: i) a stereoselective aldol addition of 2 oxoacids to methanal catalyzed by two enantiocomplementary 2 oxoacid aldolases, ii) oxidative decarboxylation, and iii) esterification. Compounds with S-configuration were obtained in 69-80% isolated yields (94-99% ee), and the R enantiomers in 57-88% (88-95% ee), using a substrate concentration range of 0.1-1.0 M. The method developed offers a versatile alternative route to this important class of chiral building blocks, and highlights the exciting opportunities available for using natural enzymes with minimal active site modification.

Authors: Roser Marín-Valls, Karel Hernández, Michael Bolte, Jesús Joglar, Jordi Bujons, Pere Clapés

Date Published: 8th Jul 2019

Publication Type: Not specified

Chroman-4-One Derivatives Targeting Pteridine Reductase 1 and Showing Anti-Parasitic Activity.

Abstract (Expand)

Flavonoids have previously been identified as antiparasitic agents and pteridine reductase 1 (PTR1) inhibitors. Herein, we focus our attention on the chroman-4-one scaffold. Three chroman-4-one analogues … (1-3) of previously published chromen-4-one derivatives were synthesized and biologically evaluated against parasitic enzymes (Trypanosoma brucei PTR1-TbPTR1 and Leishmania major-LmPTR1) and parasites (Trypanosoma brucei and Leishmania infantum). A crystal structure of TbPTR1 in complex with compound 1 and the first crystal structures of LmPTR1-flavanone complexes (compounds 1 and 3) were solved. The inhibitory activity of the chroman-4-one and chromen-4-one derivatives was explained by comparison of observed and predicted binding modes of the compounds. Compound 1 showed activity both against the targeted enzymes and the parasites with a selectivity index greater than 7 and a low toxicity. Our results provide a basis for further scaffold optimization and structure-based drug design aimed at the identification of potent anti-trypanosomatidic compounds targeting multiple PTR1 variants.

Authors: F. Di Pisa, G. Landi, L. Dello Iacono, C. Pozzi, C. Borsari, S. Ferrari, M. Santucci, N. Santarem, A. Cordeiro-da-Silva, C. B. Moraes, L. M. Alcantara, V. Fontana, L. H. Freitas-Junior, S. Gul, M. Kuzikov, B. Behrens, I. Pohner, R. C. Wade, M. P. Costi, S. Mangani

Date Published: 8th Mar 2017

Publication Type: Journal

Circadian protein regulation in the green lineage I. A phospho-dawn anticipates light onset before proteins peak in daytime.

Abstract (Expand)

BioRxiv preprint, 4 April 2018. Abstract: Daily light-dark cycles (LD) drive dynamic regulation of plant and algal transcriptomes via photoreceptor pathways and 24-hour, circadian rhythms. Diel regulation … of protein levels and modifications has been less studied. Ostreococcus tauri, the smallest free-living eukaryote, provides a minimal model proteome for the green lineage. Here, we compare transcriptome data under LD to the algal proteome and phosphoproteome, assayed using shotgun mass-spectrometry. Under 10% of 855 quantified proteins were rhythmic but two-thirds of 860 phosphoproteins showed rhythmic modification(s). Most rhythmic proteins peaked in the daytime. Model simulations showed that light-stimulated protein synthesis largely accounts for this distribution of protein peaks. Prompted by apparently dark-stable proteins, we sampled during prolonged dark adaptation, where stable RNAs and very limited change to the proteome suggested a quiescent, cellular “dark state”. In LD, acid-directed and proline-directed protein phosphorylation sites were regulated in antiphase. Strikingly, 39% of rhythmic phospho-sites reached peak levels just before dawn. This anticipatory phosphorylation is distinct from light-responsive translation but consistent with plant phosphoprotein profiles, suggesting that a clock-regulated phospho-dawn prepares green cells for daytime functions.

Authors: Zeenat B. Noordally, Matthew M. Hindle, Sarah F. Martin, Daniel D. Seaton, Ian Simpson, Thierry Le Bihan, Andrew J. Millar

Date Published: No date defined

Publication Type: Not specified

Clinical and immunologic features in severe and moderate Coronavirus Disease 2019

Abstract

Not specified

Authors: Guang Chen, Di Wu, Wei Guo, Yong Cao, Da Huang, Hongwu Wang, Tao Wang, Xiaoyun Zhang, Huilong Chen, Haijing Yu, Xiaoping Zhang, Minxia Zhang, Shiji Wu, Jianxin Song, Tao Chen, Meifang Han, Shusheng Li, Xiaoping Luo, Jianping Zhao, Qin Ning

Date Published: 27th Mar 2020

Publication Type: Journal

Clinical characteristics of 2019 novel coronavirus infection in China

Abstract (Expand)

Background: Since December 2019, acute respiratory disease (ARD) due to 2019 novel coronavirus (2019-nCoV) emerged in Wuhan city and rapidly spread throughout China. We sought to delineate the clinical … characteristics of these cases.

Authors: Wei-jie Guan, Zheng-yi Ni, Yu Hu, Wen-hua Liang, Chun-quan Ou, Jian-xing He, Lei Liu, Hong Shan, Chun-liang Lei, David SC Hui, Bin Du, Lan-juan Li, Guang Zeng, Kowk-Yung Yuen, Ru-chong Chen, Chun-li Tang, Tao Wang, Ping-yan Chen, Jie Xiang, Shi-yue Li, Jin-lin Wang, Zi-jing Liang, Yi-xiang Peng, Li Wei, Yong Liu, Ya-hua Hu, Peng Peng, Jian-ming Wang, Ji-yang Liu, Zhong Chen, Gang Li, Zhi-jian Zheng, Shao-qin Qiu, Jie Luo, Chang-jiang Ye, Shao-yong Zhu, Nan-shan Zhong

Date Published: 9th Feb 2020

Publication Type: Tech report

Clinical Characteristics of Coronavirus Disease 2019 in China

Abstract (Expand)

BACKGROUND Since December 2019, when coronavirus disease 2019 (Covid-19) emerged in Wuhan city and rapidly spread throughout China, data have been needed on the clinical characteristics of the affected … patients. METHODS We extracted data regarding 1099 patients with laboratory-confirmed Covid-19 from 552 hospitals in 30 provinces, autonomous regions, and municipalities in mainland China through January 29, 2020. The primary composite end point was admission to an intensive care unit (ICU), the use of mechanical ventilation, or death. The authors’ full names, academic degrees, and affiliations are listed in the Appendix. Address reprint requests to Dr. Zhong at the State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, First Affiliated Hospital of Guangzhou Medical University, 151 Yanjiang Rd., Guangzhou, Guangdong, China, or at ­nanshan@­vip.­163.­com. RESULTS The median age of the patients was 47 years; 41.9% of the patients were female. The primary composite end point occurred in 67 patients (6.1%), including 5.0% who were admitted to the ICU, 2.3% who underwent invasive mechanical ventilation, and 1.4% who died. Only 1.9% of the patients had a history of direct contact with wildlife. Among nonresidents of Wuhan, 72.3% had contact with residents of Wuhan, including 31.3% who had visited the city. The most common symptoms were fever (43.8% on admission and 88.7% during hospitalization) and cough (67.8%). Diarrhea was uncommon (3.8%). The median incubation period was 4 days (interquartile range, 2 to 7). On admission, ground-glass opacity was the most common radiologic finding on chest computed tomography (CT) (56.4%). No radiographic or CT abnormality was found in 157 of 877 patients (17.9%) with nonsevere disease and in 5 of 173 patients (2.9%) with severe disease. Lymphocytopenia was present in 83.2% of the patients on admission. *A list of investigators in the China Medical Treatment Expert Group for Covid-19 study is provided in the Supplementary Appendix, available at NEJM.org. Drs. Guan, Ni, Yu Hu, W. Liang, Ou, He, L. Liu, Shan, Lei, Hui, Du, L. Li, Zeng, and Yuen contributed equally to this article. This article was published on February 28, 2020, and last updated on March 6, 2020, at NEJM.org. DOI: 10.1056/NEJMoa2002032 Copyright © 2020 Massachusetts Medical Society. CONCLUSIONS During the first 2 months of the current outbreak, Covid-19 spread rapidly throughout China and caused varying degrees of illness. Patients often presented without fever, and many did not have abnormal radiologic findings. (Funded by the National Health Commission of China and others.)

Authors: Wei-jie Guan, Zheng-yi Ni, Yu Hu, Wen-hua Liang, Chun-quan Ou, Jian-xing He, Lei Liu, Hong Shan, Chun-liang Lei, David S.C. Hui, Bin Du, Lan-juan Li, Guang Zeng, Kwok-Yung Yuen, Ru-chong Chen, Chun-li Tang, Tao Wang, Ping-yan Chen, Jie Xiang, Shi-yue Li, Jin-lin Wang, Zi-jing Liang, Yi-xiang Peng, Li Wei, Yong Liu, Ya-hua Hu, Peng Peng, Jian-ming Wang, Ji-yang Liu, Zhong Chen, Gang Li, Zhi-jian Zheng, Shao-qin Qiu, Jie Luo, Chang-jiang Ye, Shao-yong Zhu, Nan-shan Zhong

Date Published: 28th Feb 2020

Publication Type: Journal

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study

Abstract (Expand)

Background Since December, 2019, Wuhan, China, has experienced an outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological … and clinical characteristics of patients with COVID-19 have been reported but risk factors for mortality and a detailed clinical course of illness, including viral shedding, have not been well described.

Authors: Fei Zhou, Ting Yu, Ronghui Du, Guohui Fan, Ying Liu, Zhibo Liu, Jie Xiang, Yeming Wang, Bin Song, Xiaoying Gu, Lulu Guan, Yuan Wei, Hui Li, Xudong Wu, Jiuyang Xu, Shengjin Tu, Yi Zhang, Hua Chen, Bin Cao

Date Published: 1st Mar 2020

Publication Type: Journal

Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China

Abstract (Expand)

Background A recent cluster of pneumonia cases in Wuhan, China, was caused by a novel betacoronavirus, the 2019 novel coronavirus (2019-nCoV). We report the epidemiological, clinical, laboratory, and … radiological characteristics and treatment and clinical outcomes of these patients.

Authors: Chaolin Huang, Yeming Wang, Xingwang Li, Lili Ren, Jianping Zhao, Yi Hu, Li Zhang, Guohui Fan, Jiuyang Xu, Xiaoying Gu, Zhenshun Cheng, Ting Yu, Jiaan Xia, Yuan Wei, Wenjuan Wu, Xuelei Xie, Wen Yin, Hui Li, Min Liu, Yan Xiao, Hong Gao, Li Guo, Jungang Xie, Guangfa Wang, Rongmeng Jiang, Zhancheng Gao, Qi Jin, Jianwei Wang, Bin Cao

Date Published: 1st Feb 2020

Publication Type: Journal

ClpP modulates the activity of the Bacillus subtilis stress response transcription factor, sigmaB

Abstract (Expand)

The general stress regulon of Bacillus subtilis is controlled by the activity state of sigmaB, a transcription factor that is switched on following exposure to either physical or nutritional stress. … ClpP is the proteolytic component of an ATP-dependent protease that is essential for the proper regulation of multiple adaptive responses in B. subtilis. Among the proteins whose abundance increases in ClpP- B. subtilis are several known to depend on sigmaB for their expression. In the current work we examine the relationship of ClpP to the activity of sigmaB. The data reveal that the loss of ClpP in otherwise wild-type B. subtilis results in a small increase in sigmaB activity during growth and a marked enhancement of sigmaB activity following its induction by either physical or nutritional stress. It appears to be the persistence of sigmaB's activity rather than its induction that is principally affected by the loss of ClpP. sigmaB-dependent reporter gene activity rose in parallel in ClpP+ and ClpP- B. subtilis strains but failed to display its normal transience in the ClpP- strain. The putative ClpP targets are likely to be stress generated and novel. Enhanced sigmaB activity in ClpP- B. subtilis was triggered by physical stress but not by the induced synthesis of the physical stress pathway's positive regulator (RsbT). In addition, Western blot analyses failed to detect differences in the levels of the principal known sigmaB regulators in ClpP+ and ClpP- B. subtilis strains. The data suggest a model in which ClpP facilitates the turnover of stress-generated factors, which persist in ClpP's absence to stimulate ongoing sigmaB activity.

Authors: Adam Reeves, Ulf Gerth, , W G Haldenwang

Date Published: 22nd Jun 2007

Publication Type: Not specified

Combining dictionary- and rule-based approximate entity linking with tuned BioBERT

Abstract (Expand)

Chemical named entity recognition (NER) is a significant step for many downstream applications like entity linking for the chemical text-mining pipeline. However, the identification of chemical entities … in a biomedical text is a challenging task due to the diverse morphology of chemical entities and the different types of chemical nomenclature. In this work, we describe our approach that was submitted for BioCreative version 7 challenge Track 2, focusing on the ‘Chemical Identification’ task for identifying chemical entities and entity linking, using MeSH. For this purpose, we have applied a two-stage approach as follows (a) usage of fine-tuned BioBERT for identification of chemical entities (b) semantic approximate search in MeSH and PubChem databases for entity linking. There was some friction between the two approaches, as our rule-based approach did not harmonise optimally with partially recognized words forwarded by the BERT component. For our future work, we aim to resolve the issue of the artefacts arising from BERT tokenizers and develop joint learning of chemical named entity recognition and entity linking using pre-trained transformer-based models and compare their performance with our preliminary approach. Next, we will improve the efficiency of our approximate search in reference databases during entity linking. This task is non-trivial as it entails determining similarity scores of large sets of trees with respect to a query tree. Ideally, this will enable flexible parametrization and rule selection for the entity linking search.

Authors: Ghadeer Mobasher, Lukrécia Mertová, Sucheta Ghosh, Olga Krebs, Bettina Heinlein, Wolfgang Müller

Date Published: 11th Nov 2021

Publication Type: Proceedings

Comparative mapping of on-targets and off-targets for the discovery of anti-trypanosomatid folate pathway inhibitors.

Abstract (Expand)

BACKGROUND: Multi-target approaches are necessary to properly analyze or modify the function of a biochemical pathway or a protein family. An example of such a problem is the repurposing of the known … human anti-cancer drugs, antifolates, as selective anti-parasitic agents. This requires considering a set of experimentally validated protein targets in the folate pathway of major pathogenic trypanosomatid parasites and humans: (i) the primary parasite on-targets: pteridine reductase 1 (PTR1) (absent in humans) and bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS), (ii) the primary off-targets: human DHFR and TS, and (iii) the secondary on-target: human folate receptor beta, a folate/antifolate transporter. METHODS: We computationally compared the structural, dynamic and physico-chemical properties of the targets. We based our analysis on available inhibitory activity and crystallographic data, including a crystal structure of the bifunctional T. cruzi DHFR-TS with tetrahydrofolate bound determined in this work. Due to the low sequence and structural similarity of the targets analyzed, we employed a mapping of binding pockets based on the known common ligands, folate and methotrexate. RESULTS: Our analysis provides a set of practical strategies for the design of selective trypanosomatid folate pathway inhibitors, which are supported by enzyme inhibition measurements and crystallographic structures. CONCLUSIONS: The ligand-based comparative computational mapping of protein binding pockets provides a basis for repurposing of anti-folates and the design of new anti-trypanosmatid agents. GENERAL SIGNIFICANCE: Apart from the target-based discovery of selective compounds, our approach may be also applied for protein engineering or analyzing evolutionary relationships in protein families.

Authors: J. Panecka-Hofman, I. Pohner, F. Spyrakis, T. Zeppelin, F. Di Pisa, L. Dello Iacono, A. Bonucci, A. Quotadamo, A. Venturelli, S. Mangani, M. P. Costi, R. C. Wade

Date Published: 25th Sep 2017

Publication Type: Journal

Comparison of 432 Pseudomonas strains through integration of genomic, functional, metabolic and expression data.

Abstract (Expand)

Pseudomonas is a highly versatile genus containing species that can be harmful to humans and plants while others are widely used for bioengineering and bioremediation. We analysed 432 sequenced Pseudomonas … strains by integrating results from a large scale functional comparison using protein domains with data from six metabolic models, nearly a thousand transcriptome measurements and four large scale transposon mutagenesis experiments. Through heterogeneous data integration we linked gene essentiality, persistence and expression variability. The pan-genome of Pseudomonas is closed indicating a limited role of horizontal gene transfer in the evolutionary history of this genus. A large fraction of essential genes are highly persistent, still non essential genes represent a considerable fraction of the core-genome. Our results emphasize the power of integrating large scale comparative functional genomics with heterogeneous data for exploring bacterial diversity and versatility.

Authors: J. J. Koehorst, J. C. van Dam, R. G. van Heck, E. Saccenti, V. A. Dos Santos, M. Suarez-Diez, P. J. Schaap

Date Published: 6th Dec 2016

Publication Type: Journal

Comparison of in vitro/in vivo blood distribution and pharmacokinetics of artemisinin, artemether and dihydroartemisinin in rats

Abstract

Not specified

Authors: Tianming Dai, Weifan Jiang, Zizheng Guo, Yanxiang Xie, Renke Dai

Date Published: 2019

Publication Type: Journal

Comprehensive identification and quantification of microbial transcriptomes by genome-wide unbiased methods

Abstract (Expand)

Genomic tiling array transcriptomics and RNA-seq are two powerful and rapidly developing approaches for unbiased transcriptome analysis. Providing comprehensive identification and quantification of … transcripts with an unprecedented resolution, they are leading to major breakthroughs in systems biology. Here we review each step of the analysis from library preparation to the interpretation of the data, with particular attention paid to the possible sources of artifacts. Methodological requirements and statistical frameworks are often similar in both the approaches despite differences in the nature of the data. Tiling array analysis does not require rRNA depletion and benefits from a more mature computational workflow, whereas RNA-Seq has a clear lead in terms of background noise and dynamic range with a considerable potential for evolution with the improvements of sequencing technologies. Being independent of prior sequence knowledge, RNA-seq will boost metatranscriptomics and evolutionary transcriptomics applications.

Authors: , Pierre Nicolas, Hugues Richard, Philippe Bessières, Stéphane Aymerich

Date Published: 10th Nov 2010

Publication Type: Not specified

Computational processing and error reduction strategies for standardized quantitative data in biological networks.

Abstract (Expand)

High-quality quantitative data generated under standardized conditions is critical for understanding dynamic cellular processes. We report strategies for error reduction, and algorithms for automated … data processing and for establishing the widely used techniques of immunoprecipitation and immunoblotting as highly precise methods for the quantification of protein levels and modifications. To determine the stoichiometry of cellular components and to ensure comparability of experiments, relative signals are converted to absolute values. A major source for errors in blotting techniques are inhomogeneities of the gel and the transfer procedure leading to correlated errors. These correlations are prevented by randomized gel loading, which significantly reduces standard deviations. Further error reduction is achieved by using housekeeping proteins as normalizers or by adding purified proteins in immunoprecipitations as calibrators in combination with criteria-based normalization. Additionally, we developed a computational tool for automated normalization, validation and integration of data derived from multiple immunoblots. In this way, large sets of quantitative data for dynamic pathway modeling can be generated, enabling the identification of systems properties and the prediction of targets for efficient intervention.

Authors: M. Schilling, T. Maiwald, S. Bohl, M. Kollmann, C. Kreutz, J. Timmer, U. Klingmuller

Date Published: 13th Dec 2005

Publication Type: Journal

Computer controlled automated assay for comprehensive studies of enzyme kinetic parameters

Abstract (Expand)

Stability and biological activity of proteins is highly dependent on their physicochemical environment. The development of realistic models of biological systems necessitates quantitative information … on the response to changes of external conditions like pH, salinity and concentrations of substrates and allosteric modulators. Changes in just a few variable parameters rapidly lead to large numbers of experimental conditions, which go beyond the experimental capacity of most research groups. We implemented a computer-aided experimenting framework ("robot lab assistant") that allows us to parameterize abstract, human-readable descriptions of micro-plate based experiments with variable parameters and execute them on a conventional 8 channel liquid handling robot fitted with a sensitive plate reader. A set of newly developed R-packages translates the instructions into machine commands, executes them, collects the data and processes it without user-interaction. By combining script-driven experimental planning, execution and data-analysis, our system can react to experimental outcomes autonomously, allowing outcome-based iterative experimental strategies. The framework was applied in a response-surface model based iterative optimization of buffer conditions and investigation of substrate, allosteric effector, pH and salt dependent activity profiles of pyruvate kinase (PYK). A diprotic model of enzyme kinetics was used to model the combined effects of changing pH and substrate concentrations. The 8 parameters of the model could be estimated from a single two-hour experiment using nonlinear least-squares regression. The model with the estimated parameters successfully predicted pH and PEP dependence of initial reaction rates, while the PEP concentration dependent shift of optimal pH could only be reproduced with a set of manually tweaked parameters. Differences between model-predictions and experimental observations at low pH suggest additional protonation-sites at the enzyme or substrates critical for enzymatic activity. The developed framework is a powerful tool to investigate enzyme reaction specifics and explore biological system behaviour in a wide range of experimental conditions.

Authors: Felix Bonowski, , , Jinda Holzwarth, Igor Kitanovic, Van Ngoc Bui, Elke Lederer,

Date Published: 23rd Dec 2009

Publication Type: Not specified

Conceptual and computational framework for logical modelling of biological networks deregulated in diseases.

Abstract (Expand)

Mathematical models can serve as a tool to formalize biological knowledge from diverse sources, to investigate biological questions in a formal way, to test experimental hypotheses, to predict the … effect of perturbations and to identify underlying mechanisms. We present a pipeline of computational tools that performs a series of analyses to explore a logical model's properties. A logical model of initiation of the metastatic process in cancer is used as a transversal example. We start by analysing the structure of the interaction network constructed from the literature or existing databases. Next, we show how to translate this network into a mathematical object, specifically a logical model, and how robustness analyses can be applied to it. We explore the visualization of the stable states, defined as specific attractors of the model, and match them to cellular fates or biological read-outs. With the different tools we present here, we explain how to assign to each solution of the model a probability and how to identify genetic interactions using mutant phenotype probabilities. Finally, we connect the model to relevant experimental data: we present how some data analyses can direct the construction of the network, and how the solutions of a mathematical model can also be compared with experimental data, with a particular focus on high-throughput data in cancer biology. A step-by-step tutorial is provided as a Supplementary Material and all models, tools and scripts are provided on an accompanying website: https://github.com/sysbio-curie/Logical_modelling_pipeline.

Authors: A. Montagud, P. Traynard, L. Martignetti, E. Bonnet, E. Barillot, A. Zinovyev, L. Calzone

Date Published: 19th Jul 2019

Publication Type: Journal

Condition-dependent transcriptome reveals high-level regulatory architecture in Bacillus subtilis

Abstract (Expand)

Bacteria adapt to environmental stimuli by adjusting their transcriptomes in a complex manner, the full potential of which has yet to be established for any individual bacterial species. Here, we report … the transcriptomes of Bacillus subtilis exposed to a wide range of environmental and nutritional conditions that the organism might encounter in nature. We comprehensively mapped transcription units (TUs) and grouped 2935 promoters into regulons controlled by various RNA polymerase sigma factors, accounting for ~66% of the observed variance in transcriptional activity. This global classification of promoters and detailed description of TUs revealed that a large proportion of the detected antisense RNAs arose from potentially spurious transcription initiation by alternative sigma factors and from imperfect control of transcription termination.

Authors: Pierre Nicolas, , Etienne Dervyn, Tatiana Rochat, Aurélie Leduc, Nathalie Pigeonneau, Elena Bidnenko, Elodie Marchadier, Mark Hoebeke, Stéphane Aymerich, Dörte Becher, Paola Bisicchia, Eric Botella, Olivier Delumeau, Geoff Doherty, Emma L Denham, Mark J Fogg, Vincent Fromion, Anne Goelzer, Annette Hansen, Elisabeth Härtig, , Georg Homuth, Hanne Jarmer, Matthieu Jules, Edda Klipp, Ludovic Le Chat, François Lecointe, , Wolfram Liebermeister, Anika March, , , David Noone, Susanne Pohl, Bernd Rinn, Frank Rügheimer, , Franck Samson, Marc Schaffer, Benno Schwikowski, , , Thomas Wiegert, Kevin M Devine, Anthony J Wilkinson, , , , Philippe Bessières, Philippe Noirot

Date Published: 3rd Mar 2012

Publication Type: Not specified

Connecting parts with processes: SubtiWiki and SubtiPathways integrate gene and pathway annotation for Bacillus subtilis

Abstract (Expand)

Bacillus subtilis is the model organism for a large group of Gram-positive bacteria, the Firmicutes. Several online databases have been established over time to manage its genetic and metabolic … information, but they differ greatly in their rate of update and their focus on B. subtilis. Therefore, a European systems biology consortium called for an integrated solution that empowers its users to enrich online content. To meet this goal we created SubtiWiki and SubtiPathways, two complementary online tools for gene and pathway information on B. subtilis 168. SubtiWiki (http://subtiwiki.uni-goettingen.de/ ) is a scientific wiki for all genes of B. subtilis and their protein or RNA products. Each gene page contains a summary of the most important information; sections on the gene, its product and expression; sections concerning biological materials and laboratories; and a list of references. SubtiWiki has been seeded with key content and can be extended by any researcher after a simple registration, thus keeping it always up to date. As a complement, SubtiPathways (http://subtipathways.uni-goettingen.de/) is an online tool for navigation of the metabolism of B. subtilis and its regulation. Each SubtiPathways diagram presents a metabolic pathway with its participating enzymes, together with the regulatory mechanisms that act on their expression and activity, in an intuitive interface that is based on Google Maps. Together, SubtiWiki and SubtiPathways provide an integrated view of the processes that make up B. subtilis and its components, making it the most comprehensive web resource for B. subtilis researchers.

Authors: Christoph R Lammers, , Arne G Schmeisky, Sebastian F Roppel, Ulrike Mäder, ,

Date Published: 3rd Dec 2009

Publication Type: Not specified

Construction and characterization of three lactate dehydrogenase-negative Enterococcus faecalis V583 mutants

Abstract (Expand)

The roles of the two ldh genes of Enterococcus faecalis were studied using knockout mutants. Deletion of ldh-1 causes a metabolic shift from homolactic fermentation to ethanol, formate, and acetoin … production, with a high level of formate production even under aerobic conditions. Ldh-2 plays only a minor role in lactate production.

Authors: , Zhian Saleihan, ,

Date Published: 22nd May 2009

Publication Type: Not specified

Construction and validation of a detailed kinetic model of glycolysis in Plasmodium falciparum

Abstract (Expand)

The enzymes in the Embden–Meyerhof–Parnas pathway of Plasmodium falciparum trophozoites were kinetically characterized and their integrated activities analyzed in a mathematical model. For validation … of the model, we compared model predictions for steady-state fluxes and metabolite concentrations of the hexose phosphates with experimental values for intact parasites. The model, which is completely based on kinetic parameters that were measured for the individual enzymes, gives an accurate prediction of the steady-state fluxes and intermediate concentrations. This is the first detailed kinetic model for glucose metabolism in P. falciparum, one of the most prolific malaria-causing protozoa, and the high predictive power of the model makes it a strong tool for future drug target identification studies. The modelling workflow is transparent and reproducible, and completely documented in the SEEK platform, where all experimental data and model files are available for download.

Authors: Gerald Penkler, Francois du Toit, Waldo Adams, Marina Rautenbach, Daniel C. Palm, David D. van Niekerk, Jacky L. Snoep

Date Published: 1st Apr 2015

Publication Type: Not specified

Contaminant accumulation and biological responses in Atlantic cod (Gadus morhua) caged at a capped waste disposal site in Kollevag, Western Norway.

Abstract (Expand)

The aim of this study was to assess whether fish in Kollevag, a sheltered bay on the western coast of Norway, previously utilized as a waste disposal site, could be affected by environmental contaminants … leaking from the waste. Farmed, juvenile Atlantic cod (Gadus morhua) were caged for six weeks at three different locations in Kollevag bay and at one reference location. Sediments and cod samples (bile and liver) were analyzed for polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), brominated flame retardants (BFRs), per-and polyfluoroalkyl substances (PFASs) and polycyclic aromatic hydrocarbon (PAH) metabolites, revealing a contamination gradient at the four stations. Furthermore, hepatosomatic index (HSI) and Fulton's condition factor (CF) were significantly lower in cod caged closest to the disposal site. Levels and activities of biomarker proteins, such as vitellogenin (Vtg), metallothionein (Mt), and biotransformation and oxidative stress enzymes, including cytochrome P450 1a and 3a (Cyp1a, Cyp3a), glutathione s-transferase (Gst) and catalase (Cat), were quantified in blood plasma and liver tissue. Hepatic Cat and Gst activities were significantly reduced in cod caged at the innermost stations in Kollevag, indicating modulation of oxidative stress responses. However, these results contrasted with reduced hepatic lipid peroxidation. Significant increases in transcript levels were observed for genes involved in lipid metabolism (fasn and acly) in cod liver, while transcript levels of ovarian steroidogenic enzyme genes such as p450scc, cyp19, 3beta-hsd and 20beta-hsd showed significant station-dependent increases. Cyp1a and Vtg protein levels were however not significantly altered in cod caged in Kollevag. Plasma levels of estradiol (E2) and testosterone (T) were determined by enzyme immunoassay (EIA) and showed elevated E2 levels, but only at the innermost station. We conclude that the bay of Kollevag did not fullfill adequate environmental condition based on environmental quality standards (EQSs) for chemicals in coastal waters. Following a six weeks caging period, environmental contaminants accumulated in cod tissues and effects were observed on biomarker responses, especially those involved in reproductive processes in cod ovary.

Authors: K. Dale, M. B. Muller, Z. Tairova, E. A. Khan, K. Hatlen, M. Grung, F. Yadetie, R. Lille-Langoy, N. Blaser, H. J. Skaug, J. L. Lyche, A. Arukwe, K. Hylland, O. A. Karlsen, A. Goksoyr

Date Published: 26th Feb 2019

Publication Type: Not specified

Context-specific flow through the MEK/ERK module produces cell- and ligand-specific patterns of ERK single and double phosphorylation.

Abstract (Expand)

The same pathway, such as the mitogen-activated protein kinase (MAPK) pathway, can produce different cellular responses, depending on stimulus or cell type. We examined the phosphorylation dynamics of … the MAPK kinase MEK and its targets extracellular signal-regulated kinase 1 and 2 (ERK1/2) in primary hepatocytes and the transformed keratinocyte cell line HaCaT A5 exposed to either hepatocyte growth factor or interleukin-6. By combining quantitative mass spectrometry with dynamic modeling, we elucidated network structures for the reversible threonine and tyrosine phosphorylation of ERK in both cell types. In addition to differences in the phosphorylation and dephosphorylation reactions, the HaCaT network model required two feedback mechanisms, which, as the experimental data suggested, involved the induction of the dual-specificity phosphatase DUSP6 and the scaffold paxillin. We assayed and modeled the accumulation of the double-phosphorylated and active form of ERK1/2, as well as the dynamics of the changes in the monophosphorylated forms of ERK1/2. Modeling the differences in the dynamics of the changes in the distributions of the phosphorylated forms of ERK1/2 suggested that different amounts of MEK activity triggered context-specific responses, with primary hepatocytes favoring the formation of double-phosphorylated ERK1/2 and HaCaT A5 cells that produce both the threonine-phosphorylated and the double-phosphorylated form. These differences in phosphorylation distributions explained the threshold, sensitivity, and saturation of the ERK response. We extended the findings of differential ERK phosphorylation profiles to five additional cultured cell systems and matched liver tumor and normal tissue, which revealed context-specific patterns of the various forms of phosphorylated ERK.

Authors: N. Iwamoto, L. A. D'Alessandro, S. Depner, B. Hahn, B. A. Kramer, P. Lucarelli, A. Vlasov, M. Stepath, M. E. Bohm, D. Deharde, G. Damm, D. Seehofer, W. D. Lehmann, U. Klingmuller, M. Schilling

Date Published: 2nd Feb 2016

Publication Type: Journal

Continuous time Boolean modeling for biological signaling: application of Gillespie algorithm.

Abstract (Expand)

UNLABELLED: Mathematical modeling is used as a Systems Biology tool to answer biological questions, and more precisely, to validate a network that describes biological observations and predict the … effect of perturbations. This article presents an algorithm for modeling biological networks in a discrete framework with continuous time. BACKGROUND: There exist two major types of mathematical modeling approaches: (1) quantitative modeling, representing various chemical species concentrations by real numbers, mainly based on differential equations and chemical kinetics formalism; (2) and qualitative modeling, representing chemical species concentrations or activities by a finite set of discrete values. Both approaches answer particular (and often different) biological questions. Qualitative modeling approach permits a simple and less detailed description of the biological systems, efficiently describes stable state identification but remains inconvenient in describing the transient kinetics leading to these states. In this context, time is represented by discrete steps. Quantitative modeling, on the other hand, can describe more accurately the dynamical behavior of biological processes as it follows the evolution of concentration or activities of chemical species as a function of time, but requires an important amount of information on the parameters difficult to find in the literature. RESULTS: Here, we propose a modeling framework based on a qualitative approach that is intrinsically continuous in time. The algorithm presented in this article fills the gap between qualitative and quantitative modeling. It is based on continuous time Markov process applied on a Boolean state space. In order to describe the temporal evolution of the biological process we wish to model, we explicitly specify the transition rates for each node. For that purpose, we built a language that can be seen as a generalization of Boolean equations. Mathematically, this approach can be translated in a set of ordinary differential equations on probability distributions. We developed a C++ software, MaBoSS, that is able to simulate such a system by applying Kinetic Monte-Carlo (or Gillespie algorithm) on the Boolean state space. This software, parallelized and optimized, computes the temporal evolution of probability distributions and estimates stationary distributions. CONCLUSIONS: Applications of the Boolean Kinetic Monte-Carlo are demonstrated for three qualitative models: a toy model, a published model of p53/Mdm2 interaction and a published model of the mammalian cell cycle. Our approach allows to describe kinetic phenomena which were difficult to handle in the original models. In particular, transient effects are represented by time dependent probability distributions, interpretable in terms of cell populations.

Authors: G. Stoll, E. Viara, E. Barillot, L. Calzone

Date Published: 29th Aug 2012

Publication Type: Journal

Contributions of the pre- and pro-regions of a Staphylococcus hyicus lipase to secretion of a heterologous protein by Bacillus subtilis

Abstract (Expand)

Bacillus subtilis is a well-established cell factory for efficient secretion of many biotechnologically relevant enzymes that are naturally produced by it or related organisms. However, the use of B. … subtilis as a host for production of heterologous secretory proteins can be complicated by problems related to inefficient translocation of the foreign proteins across the plasma membrane or to inefficient release of the exported proteins from the cell surface into the surrounding medium. Therefore, there is a clear need for tools that allow more efficient membrane targeting, translocation, and release during the production of these proteins. In the present study, we investigated the contributions of the pre (pre(lip)) and pro (pro(lip)) sequences of a Staphylococcus hyicus lipase to secretion of a heterologous protein, the alkaline phosphatase PhoA of Escherichia coli, by B. subtilis. The results indicate that the presence of the pro(lip)-peptide, in combination with the lipase signal peptide (pre(lip)), contributes significantly to the efficient secretion of PhoA by B. subtilis and that pre(lip) directs PhoA secretion more efficiently than the authentic signal peptide of PhoA. Genome-wide transcriptional analyses of the host cell responses indicate that, under the conditions tested, no known secretion or membrane-cell wall stress responses were provoked by the production of PhoA with any of the pre- and pro-region sequences used. Our data underscore the view that the pre-pro signals of the S. hyicus lipase are very useful tools for secretion of heterologous proteins in B. subtilis.

Authors: Thijs R H M Kouwen, Allan K Nielsen, Emma L Denham, Jean-Yves F Dubois, Ronald Dorenbos, Michael D Rasmussen, Wim J Quax, Roland Freudl,

Date Published: 30th Nov 2009

Publication Type: Not specified

Control of cell division in Streptococcus pneumoniae by the conserved Ser/Thr protein kinase StkP

Abstract (Expand)

How the human pathogen Streptococcus pneumoniae coordinates cell-wall synthesis during growth and division to achieve its characteristic oval shape is poorly understood. The conserved eukaryotic-type … Ser/Thr kinase of S. pneumoniae, StkP, previously was reported to phosphorylate the cell-division protein DivIVA. Consistent with a role in cell division, GFP-StkP and its cognate phosphatase, GFP-PhpP, both localize to the division site. StkP localization depends on its penicillin-binding protein and Ser/Thr-associated domains that likely sense uncross-linked peptidoglycan, because StkP and PhpP delocalize in the presence of antibiotics that target the latest stages of cell-wall biosynthesis and in cells that have stopped dividing. Time-lapse microscopy shows that StkP displays an intermediate timing of recruitment to midcell: StkP arrives shortly after FtsA but before DivIVA. Furthermore, StkP remains at midcell longer than FtsA, until division is complete. Cells mutated for stkP are perturbed in cell-wall synthesis and display elongated morphologies with multiple, often unconstricted, FtsA and DivIVA rings. The data show that StkP plays an important role in regulating cell-wall synthesis and controls correct septum progression and closure. Overall, our results indicate that StkP signals information about the cell-wall status to key cell-division proteins and in this way acts as a regulator of cell division.

Authors: Katrin Beilharz, Linda Nováková, Daniela Fadda, Pavel Branny, Orietta Massidda,

Date Published: 21st Mar 2012

Publication Type: Not specified

Control of transcription elongation by GreA determines rate of gene expression in Streptococcus pneumoniae

Abstract (Expand)

Transcription by RNA polymerase may be interrupted by pauses caused by backtracking or misincorporation that can be resolved by the conserved bacterial Gre-factors. However, the consequences of such … pausing in the living cell remain obscure. Here, we developed molecular biology and transcriptome sequencing tools in the human pathogen Streptococcus pneumoniae and provide evidence that transcription elongation is rate-limiting on highly expressed genes. Our results suggest that transcription elongation may be a highly regulated step of gene expression in S. pneumoniae. Regulation is accomplished via long-living elongation pauses and their resolution by elongation factor GreA. Interestingly, mathematical modeling indicates that long-living pauses cause queuing of RNA polymerases, which results in 'transcription traffic jams' on the gene and thus blocks its expression. Together, our results suggest that long-living pauses and RNA polymerase queues caused by them are a major problem on highly expressed genes and are detrimental for cell viability. The major and possibly sole function of GreA in S. pneumoniae is to prevent formation of backtracked elongation complexes.

Authors: , , M. Herber, L. Attaiech, , , S. Klumpp, ,

Date Published: 6th Sep 2014

Publication Type: Not specified

Controlled interplay between trigger loop and Gre factor in the RNA polymerase active centre

Abstract (Expand)

The highly processive transcription by multi-subunit RNA polymerases (RNAP) can be interrupted by misincorporation or backtracking events that may stall transcription or lead to erroneous transcripts. … Backtracked/misincorporated complexes can be resolved via hydrolysis of the transcript. Here, we show that, in response to misincorporation and/or backtracking, the catalytic domain of RNAP active centre, the trigger loop (TL), is substituted by transcription factor Gre. This substitution turns off the intrinsic TL-dependent hydrolytic activity of RNAP active centre, and exchanges it to a far more efficient Gre-dependent mechanism of RNA hydrolysis. Replacement of the TL by Gre factor occurs only in backtracked/misincorporated complexes, and not in correctly elongating complexes. This controlled switching of RNAP activities allows the processivity of elongation to be unaffected by the hydrolytic activity of Gre, while ensuring efficient proofreading of transcription and resolution of backtracked complexes.

Authors: Mohammad Roghanian, ,

Date Published: 27th Jan 2011

Publication Type: Not specified

Convergent in situ Generation of Both Transketolase Substrates via Transaminase and Aldolase Reactions for Sequential One‐Pot, Three‐Step Cascade Synthesis of Ketoses

Abstract

Not specified

Authors: Marion Lorillière, Christine Guérard‐Hélaine, Thierry Gefflaut, Wolf‐Dieter Fessner, Pere Clapés, Franck Charmantray, Laurence Hecquet

Date Published: 12th Dec 2019

Publication Type: Journal

Copy number profiling by array comparative genomic hybridization identifies frequently occurring BRCA2-like male breast cancer.

Abstract (Expand)

Genomic aberrations can be used to subtype breast cancer. In this study, we investigated DNA copy number (CN) profiles of 69 cases of male breast cancer (MBC) by array comparative genomic hybridization … (aCGH) to detect recurrent gains and losses in comparison with female breast cancers (FBC). Further, we classified these profiles as BRCA1-like, BRCA2-like or non-BRCA-like profiles using previous classifiers derived from FBC, and correlated these profiles with pathological characteristics. We observed large CN gains on chromosome arms 1q, 5p, 8q, 10p, 16p, 17q, and chromosomes 20 and X. Large losses were seen on chromosomes/chromosome arms 1p, 6p, 8p, 9, 11q, 13, 14q, 16q, 17p, and 22. The pattern of gains and losses in estrogen receptor positive (ER+) MBC was largely similar to ER+ FBC, except for gains on chromosome X in MBC, which were uncommon in FBC. Out of 69 MBC patients, 15 patients (22%) had a BRCA2-like profile, of which 2 (3%) were also BRCA1-like. One patient (1%) was only BRCA1-like; the remaining 53 (77%) patients were classified as non-BRCA-like. BRCA2-like cases were more often p53 accumulated than non-BRCA-like cases (P = 0.014). In conclusion, the pattern of gains and losses in ER+ MBC was largely similar to that of its ER+ FBC counterpart, except for gains on chromosome X in MBC, which are uncommon in FBC. A significant proportion of MBC has a BRCA2-like aCGH profile, pointing to a potentially hereditary nature, and indicating that they could benefit from a drug regimen targeting BRCA defects as in FBC.

Authors: H. D. Biesma, P. C. Schouten, M. M. Lacle, J. Sanders, W. Brugman, R. Kerkhoven, I. Mandjes, P. van der Groep, P. J. van Diest, S. C. Linn

Date Published: 11th Sep 2015

Publication Type: Journal

Coronavirus infections and immune responses

Abstract (Expand)

Coronaviruses (CoVs) are by far the largest group of known positive-sense RNA viruses having an extensive range of natural hosts. In the past few decades, newly evolved Coronaviruses have posed a global … threat to public health. The immune response is essential to control and eliminate CoV infections, however, maladjusted immune responses may result in immunopathology and impaired pulmonary gas exchange. Gaining a deeper understanding of the interaction between Coronaviruses and the innate immune systems of the hosts may shed light on the development and persistence of inflammation in the lungs and hopefully can reduce the risk of lung inflammation caused by CoVs. In this review, we provide an update on CoV infections and relevant diseases, particularly the host defense against CoV-induced inflammation of lung tissue, as well as the role of the innate immune system in the pathogenesis and clinical treatment.

Authors: Geng Li, Yaohua Fan, Yanni Lai, Tiantian Han, Zonghui Li, Peiwen Zhou, Pan Pan, Wenbiao Wang, Dingwen Hu, Xiaohong Liu, Qiwei Zhang, Jianguo Wu

Date Published: 7th Feb 2020

Publication Type: Journal

Coronaviruses post-SARS: update on replication and pathogenesis

Abstract

Not specified

Authors: Stanley Perlman, Jason Netland

Date Published: 1st Jun 2009

Publication Type: Journal

Covering a broad dynamic range: information processing at the erythropoietin receptor.

Abstract (Expand)

Cell surface receptors convert extracellular cues into receptor activation, thereby triggering intracellular signaling networks and controlling cellular decisions. A major unresolved issue is the … identification of receptor properties that critically determine processing of ligand-encoded information. We show by mathematical modeling of quantitative data and experimental validation that rapid ligand depletion and replenishment of the cell surface receptor are characteristic features of the erythropoietin (Epo) receptor (EpoR). The amount of Epo-EpoR complexes and EpoR activation integrated over time corresponds linearly to ligand input; this process is carried out over a broad range of ligand concentrations. This relation depends solely on EpoR turnover independent of ligand binding, which suggests an essential role of large intracellular receptor pools. These receptor properties enable the system to cope with basal and acute demand in the hematopoietic system.

Authors: V. Becker, M. Schilling, J. Bachmann, U. Baumann, A. Raue, T. Maiwald, J. Timmer, U. Klingmuller

Date Published: 11th Jun 2010

Publication Type: Journal

COVID-19: Attacks the 1-Beta Chain of Hemoglobin and Captures the Porphyrin to Inhibit Human Heme Metabolism

Abstract (Expand)

The novel coronavirus pneumonia (COVID-19) is an infectious acute respiratory infection caused by the novel coronavirus. The virus is a positive-strand RNA virus with high homology to bat coronavirus. … In this study, conserved domain analysis, homology modeling, and molecular docking were used to compare the biological roles of certain proteins of the novel coronavirus. The results showed the ORF8 and surface glycoprotein could bind to the porphyrin, respectively. At the same time, orf1ab, ORF10, and ORF3a proteins could coordinate attack the heme on the 1-beta chain of hemoglobin to dissociate the iron to form the porphyrin. The attack will cause less and less hemoglobin that can carry oxygen and carbon dioxide. The lung cells have extremely intense poisoning and inflammatory due to the inability to exchange carbon dioxide and oxygen frequently, which eventually results in ground-glass-like lung images. The mechanism also interfered with the normal heme anabolic pathway of the human body, is expected to result in human disease. According to the validation analysis of these finds, chloroquine could prevent orf1ab, ORF3a, and ORF10 to attack the heme to form the porphyrin, and inhibit the binding of ORF8 and surface glycoproteins to porphyrins to a certain extent, effectively relieve the symptoms of respiratory distress. Favipiravir could inhibit the envelope protein and ORF7a protein bind to porphyrin, prevent the virus from entering host cells, and catching free porphyrins. Because the novel coronavirus is dependent on porphyrins, it may originate from an ancient virus. Therefore, this research is of high value to contemporary biological experiments, disease prevention, and clinical treatment.

Authors: Liu Wenzhong, Li Hualan

Date Published: 30th Mar 2020

Publication Type: Journal

COVID-19: combining antiviral and anti-inflammatory treatments

Abstract

Not specified

Authors: Justin Stebbing, Anne Phelan, Ivan Griffin, Catherine Tucker, Olly Oechsle, Dan Smith, Peter Richardson

Date Published: 1st Apr 2020

Publication Type: Journal

COVID19 Disease Map, a computational knowledge repository of virus-host interaction mechanisms.

Abstract (Expand)

We need to effectively combine the knowledge from surging literature with complex datasets to propose mechanistic models of SARS-CoV-2 infection, improving data interpretation and predicting key targets … of intervention. Here, we describe a large-scale community effort to build an open access, interoperable and computable repository of COVID-19 molecular mechanisms. The COVID-19 Disease Map (C19DMap) is a graphical, interactive representation of disease-relevant molecular mechanisms linking many knowledge sources. Notably, it is a computational resource for graph-based analyses and disease modelling. To this end, we established a framework of tools, platforms and guidelines necessary for a multifaceted community of biocurators, domain experts, bioinformaticians and computational biologists. The diagrams of the C19DMap, curated from the literature, are integrated with relevant interaction and text mining databases. We demonstrate the application of network analysis and modelling approaches by concrete examples to highlight new testable hypotheses. This framework helps to find signatures of SARS-CoV-2 predisposition, treatment response or prioritisation of drug candidates. Such an approach may help deal with new waves of COVID-19 or similar pandemics in the long-term perspective.

Authors: M. Ostaszewski, A. Niarakis, A. Mazein, I. Kuperstein, R. Phair, A. Orta-Resendiz, V. Singh, S. S. Aghamiri, M. L. Acencio, E. Glaab, A. Ruepp, G. Fobo, C. Montrone, B. Brauner, G. Frishman, L. C. Monraz Gomez, J. Somers, M. Hoch, S. Kumar Gupta, J. Scheel, H. Borlinghaus, T. Czauderna, F. Schreiber, A. Montagud, M. Ponce de Leon, A. Funahashi, Y. Hiki, N. Hiroi, T. G. Yamada, A. Drager, A. Renz, M. Naveez, Z. Bocskei, F. Messina, D. Bornigen, L. Fergusson, M. Conti, M. Rameil, V. Nakonecnij, J. Vanhoefer, L. Schmiester, M. Wang, E. E. Ackerman, J. E. Shoemaker, J. Zucker, K. Oxford, J. Teuton, E. Kocakaya, G. Y. Summak, K. Hanspers, M. Kutmon, S. Coort, L. Eijssen, F. Ehrhart, D. A. B. Rex, D. Slenter, M. Martens, N. Pham, R. Haw, B. Jassal, L. Matthews, M. Orlic-Milacic, A. Senff Ribeiro, K. Rothfels, V. Shamovsky, R. Stephan, C. Sevilla, T. Varusai, J. M. Ravel, R. Fraser, V. Ortseifen, S. Marchesi, P. Gawron, E. Smula, L. Heirendt, V. Satagopam, G. Wu, A. Riutta, M. Golebiewski, S. Owen, C. Goble, X. Hu, R. W. Overall, D. Maier, A. Bauch, B. M. Gyori, J. A. Bachman, C. Vega, V. Groues, M. Vazquez, P. Porras, L. Licata, M. Iannuccelli, F. Sacco, A. Nesterova, A. Yuryev, A. de Waard, D. Turei, A. Luna, O. Babur, S. Soliman, A. Valdeolivas, M. Esteban-Medina, M. Pena-Chilet, K. Rian, T. Helikar, B. L. Puniya, D. Modos, A. Treveil, M. Olbei, B. De Meulder, S. Ballereau, A. Dugourd, A. Naldi, V. Noel, L. Calzone, C. Sander, E. Demir, T. Korcsmaros, T. C. Freeman, F. Auge, J. S. Beckmann, J. Hasenauer, O. Wolkenhauer, E. L. Wilighagen, A. R. Pico, C. T. Evelo, M. E. Gillespie, L. D. Stein, H. Hermjakob, P. D'Eustachio, J. Saez-Rodriguez, J. Dopazo, A. Valencia, H. Kitano, E. Barillot, C. Auffray, R. Balling, R. Schneider

Date Published: 19th Oct 2021

Publication Type: Journal

COVID19 Disease Map, a computational knowledge repository of virus–host interaction mechanisms

Abstract

Not specified

Authors: Marek Ostaszewski, Anna Niarakis, Alexander Mazein, Inna Kuperstein, Robert Phair, Aurelio Orta‐Resendiz, Vidisha Singh, Sara Sadat Aghamiri, Marcio Luis Acencio, Enrico Glaab, Andreas Ruepp, Gisela Fobo, Corinna Montrone, Barbara Brauner, Goar Frishman, Luis Cristóbal Monraz Gómez, Julia Somers, Matti Hoch, Shailendra Kumar Gupta, Julia Scheel, Hanna Borlinghaus, Tobias Czauderna, Falk Schreiber, Arnau Montagud, Miguel Ponce de Leon, Akira Funahashi, Yusuke Hiki, Noriko Hiroi, Takahiro G Yamada, Andreas Dräger, Alina Renz, Muhammad Naveez, Zsolt Bocskei, Francesco Messina, Daniela Börnigen, Liam Fergusson, Marta Conti, Marius Rameil, Vanessa Nakonecnij, Jakob Vanhoefer, Leonard Schmiester, Muying Wang, Emily E Ackerman, Jason E Shoemaker, Jeremy Zucker, Kristie Oxford, Jeremy Teuton, Ebru Kocakaya, Gökçe Yağmur Summak, Kristina Hanspers, Martina Kutmon, Susan Coort, Lars Eijssen, Friederike Ehrhart, Devasahayam Arokia Balaya Rex, Denise Slenter, Marvin Martens, Nhung Pham, Robin Haw, Bijay Jassal, Lisa Matthews, Marija Orlic‐Milacic, Andrea Senff Ribeiro, Karen Rothfels, Veronica Shamovsky, Ralf Stephan, Cristoffer Sevilla, Thawfeek Varusai, Jean‐Marie Ravel, Rupsha Fraser, Vera Ortseifen, Silvia Marchesi, Piotr Gawron, Ewa Smula, Laurent Heirendt, Venkata Satagopam, Guanming Wu, Anders Riutta, Martin Golebiewski, Stuart Owen, Carole Goble, Xiaoming Hu, Rupert W Overall, Dieter Maier, Angela Bauch, Benjamin M Gyori, John A Bachman, Carlos Vega, Valentin Grouès, Miguel Vazquez, Pablo Porras, Luana Licata, Marta Iannuccelli, Francesca Sacco, Anastasia Nesterova, Anton Yuryev, Anita de Waard, Denes Turei, Augustin Luna, Ozgun Babur, Sylvain Soliman, Alberto Valdeolivas, Marina Esteban‐Medina, Maria Peña‐Chilet, Kinza Rian, Tomáš Helikar, Bhanwar Lal Puniya, Dezso Modos, Agatha Treveil, Marton Olbei, Bertrand De Meulder, Stephane Ballereau, Aurélien Dugourd, Aurélien Naldi, Vincent Noël, Laurence Calzone, Chris Sander, Emek Demir, Tamas Korcsmaros, Tom C Freeman, Franck Augé, Jacques S Beckmann, Jan Hasenauer, Olaf Wolkenhauer, Egon L Wilighagen, Alexander R Pico, Chris T Evelo, Marc E Gillespie, Lincoln D Stein, Henning Hermjakob, Peter D'Eustachio, Julio Saez‐Rodriguez, Joaquin Dopazo, Alfonso Valencia, Hiroaki Kitano, Emmanuel Barillot, Charles Auffray, Rudi Balling, Reinhard Schneider

Date Published: 1st Oct 2021

Publication Type: Journal

Crassiflorone derivatives that inhibit Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH) and Trypanosoma cruzi trypanothione reductase (TcTR) and display trypanocidal activity.

Abstract (Expand)

Crassiflorone is a natural product with anti-mycobacterial and anti-gonorrhoeal properties, isolated from the stem bark of the African ebony tree Diospyros crassiflora. We noticed that its pentacyclic … core possesses structural resemblance to the quinone-coumarin hybrid 3, which we reported to exhibit a dual-targeted inhibitory profile towards Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH) and Trypanosoma cruzi trypanothione reductase (TcTR). Following this basic idea, we synthesized a small library of crassiflorone derivatives 15-23 and investigated their potential as anti-trypanosomatid agents. 19 is the only compound of the series showing a balanced dual profile at 10 muM (% inhibitionTbGAPDH = 64% and % inhibitionTcTR = 65%). In phenotypic assay, the most active compounds were 18 and 21, which at 5 muM inhibited Tb bloodstream-form growth by 29% and 38%, respectively. Notably, all the newly synthesized compounds at 10 muM did not affect viability and the status of mitochondria in human A549 and 786-O cell lines, respectively. However, further optimization that addresses metabolic liabilities including solubility, as well as cytochromes P450 (CYP1A2, CYP2C9, CYP2C19, and CYP2D6) inhibition, is required before this class of natural product-derived compounds can be further progressed.

Authors: E. Uliassi, G. Fiorani, R. L. Krauth-Siegel, C. Bergamini, R. Fato, G. Bianchini, J. Carlos Menendez, M. T. Molina, E. Lopez-Montero, F. Falchi, A. Cavalli, S. Gul, M. Kuzikov, B. Ellinger, G. Witt, C. B. Moraes, L. H. Freitas-Junior, C. Borsari, M. P. Costi, M. L. Bolognesi

Date Published: 1st Dec 2017

Publication Type: Journal

CRISPR/Cas9-mediated ablation of elovl2 in Atlantic salmon (Salmo salar L.) inhibits elongation of polyunsaturated fatty acids and induces Srebp-1 and target genes

Abstract (Expand)

Atlantic salmon can synthesize polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (20:5n-3), arachidonic acid (20:4n-6) and docosahexaenoic acid (22:6n-3) via activities of very long … chain fatty acyl elongases (Elovls) and fatty acyl desaturases (Fads), albeit to a limited degree. Understanding molecular mechanisms of PUFA biosynthesis and regulation is a pre-requisite for sustainable use of vegetable oils in aquafeeds as current sources of fish oils are unable to meet increasing demands for omega-3 PUFAs. By generating CRISPR-mediated elovl2 partial knockout (KO), we have shown that elovl2 is crucial for multi-tissue synthesis of 22:6n-3 in vivo and that endogenously synthesized PUFAs are important for transcriptional regulation of lipogenic genes in Atlantic salmon. The elovl2-KOs showed reduced levels of 22:6n-3 and accumulation of 20:5n-3 and docosapentaenoic acid (22:5n-3) in the liver, brain and white muscle, suggesting inhibition of elongation. Additionally, elovl2-KO salmon showed accumulation of 20:4n-6 in brain and white muscle. The impaired synthesis of 22:6n-3 induced hepatic expression of sterol regulatory element binding protein-1 (srebp-1), fatty acid synthase-b, Δ6fad-a, Δ5fad and elovl5. Our study demonstrates key roles of elovl2 at two penultimate steps of PUFA synthesis in vivo and suggests Srebp-1 as a main regulator of endogenous PUFA synthesis in Atlantic salmon.

Authors: Alex K. Datsomor, Nikola Zic, Keshuai Li, Rolf E. Olsen, Yang Jin, Jon Olav Vik, Rolf B. Edvardsen, Fabian Grammes, Anna Wargelius, Per Winge

Date Published: 1st Dec 2019

Publication Type: Not specified

Cross-talk between two global regulators in Streptomyces: PhoP and AfsR interact in the control of afsS, pstS and phoRP transcription

Abstract (Expand)

The regulatory proteins AfsR and PhoP control expression of the biosynthesis of actinorhodin and undecylprodigiosin in Streptomyces coelicolor. Electrophoretic mobility shift assays showed that PhoP(DBD) … does not bind directly to the actII-ORF4, redD and atrA promoters, but it binds to the afsS promoter, in a region overlapping with the AfsR operator. DNase I footprinting studies revealed a PhoP protected region of 26 nt (PHO box; two direct repeats of 11 nt) that overlaps with the AfsR binding sequence. Binding experiments indicated a competition between AfsR and PhoP; increasing concentrations of PhoP(DBD) resulted in the disappearance of the AfsR-DNA complex. Expression studies using the reporter luxAB gene coupled to afsS promoter showed that PhoP downregulates afsS expression probably by a competition with the AfsR activator. Interestingly, AfsR binds to other PhoP-regulated promoters including those of pstS (a component of the phosphate transport system) and phoRP (encoding the two component system itself). Analysis of the AfsR-protected sequences in each of these promoters allowed us to distinguish the AfsR binding sequence from the overlapping PHO box. The reciprocal regulation of the phoRP promoter by AfsR and of afsS by PhoP suggests a fine interplay of these regulators on the control of secondary metabolism.

Authors: Fernando Santos-Beneit, , Alberto Sola-Landa,

Date Published: 11th Feb 2009

Publication Type: Not specified

Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation

Abstract (Expand)

The outbreak of a novel coronavirus (2019-nCoV) represents a pandemic threat that has been declared a public health emergency of international concern. The CoV spike (S) glycoprotein is a key target … for vaccines, therapeutic antibodies, and diagnostics. To facilitate medical countermeasure development, we determined a 3.5-angstrom-resolution cryo–electron microscopy structure of the 2019-nCoV S trimer in the prefusion conformation. The predominant state of the trimer has one of the three receptor-binding domains (RBDs) rotated up in a receptor-accessible conformation. We also provide biophysical and structural evidence that the 2019-nCoV S protein binds angiotensin-converting enzyme 2 (ACE2) with higher affinity than does severe acute respiratory syndrome (SARS)-CoV S. Additionally, we tested several published SARS-CoV RBD-specific monoclonal antibodies and found that they do not have appreciable binding to 2019-nCoV S, suggesting that antibody cross-reactivity may be limited between the two RBDs. The structure of 2019-nCoV S should enable the rapid development and evaluation of medical countermeasures to address the ongoing public health crisis.

Authors: Daniel Wrapp, Nianshuang Wang, Kizzmekia S. Corbett, Jory A. Goldsmith, Ching-Lin Hsieh, Olubukola Abiona, Barney S. Graham, Jason S. McLellan

Date Published: 12th Mar 2020

Publication Type: Journal

Cultivar-specific transcriptome and pan-transcriptome reconstruction of tetraploid potato

Abstract (Expand)

Background: Although the reference genome of Solanum tuberosum group Phureja double-monoploid (DM) clone is available, knowledge on the genetic diversity of the highly heterozygous tetraploid group … Tuberosum, representing most cultivated varieties, remains largely unexplored. This lack of knowledge hinders further progress in potato research and its subsequent applications in breeding. Results: For the DM genome assembly, two only partially-overlapping gene models exist differing in a unique set of genes and intron/exon structure predictions. First step was to merge and manually curate the merged gene model, creating a union of genes in Phureja scaffold. We next compiled available RNA-Seq datasets (cca. 1.5 billion reads) for three tetraploid potato genotypes (cultivar Désirée, cultivar Rywal, and breeding clone PW363) with diverse breeding pedigrees. Short-read transcriptomes were assembled using CLC, Trinity, Velvet, and rnaSPAdes de novo assemblers using different settings to test for optimal outcome. In addition, for cultivar Rywal, PacBio Iso-Seq full-length transcriptome sequencing was also performed. Revised EvidentialGene redundancy-reducing pipeline was employed to produce accurate and complete cultivar-specific transcriptomes from assemblers output, as well as to attain the pan-transcriptome. Due to being the most diverse dataset in terms of tissues (stem, seedlings and roots) and experimental conditions, cv. Désirée was the most complete transcriptome (95.8% BUSCO completeness). For cv. Rywal and breeding clone PW363 data were available for leaf samples only and the resulting transcriptomes were less complete than cv. Désirée (89.8% and 89.3% BUSCO completeness, respectively). Cross comparison of these cultivar-specific transcriptomes and merged DM gene model suggests that the core potato transcriptome is comprised of 16,339 genes. The pan-transcriptome contains a total of 95,779 transcripts, of which 54,614 transcripts are not present in the Phureja genome. These represent the variants of the novel genes found in the potato pan-genome. Conclusions: Our analysis shows that the available gene model of double-monoploid potato from group Phureja is, to some degree, not complete. The generated transcriptomes and pan-transcriptome represent a valuable resource for potato gene variability exploration, high-throughput -omics analyses, and future breeding programmes.

Authors: Marko Petek, Maja Zagorščak, Živa Ramšak, Sheri Sanders, Elizabeth Tseng, Mohamed Zouine, Anna Coll, Kristina Gruden

Date Published: No date defined

Publication Type: Not specified

Current and Future Chemotherapy for Chagas Disease.

Abstract (Expand)

Human American trypanosomiasis, commonly called Chagas disease, is one of the most neglected illnesses in the world and remains one of the most prevalent chronic infectious diseases of Latin America … with thousands of new cases every year. The only treatments available have been introduced five decades ago. They have serious, undesirable side effects and disputed benefits in the chronic stage of the disease - a characteristic and debilitating cardiomyopathy and/or megavisceras. Several laboratories have therefore focused their efforts in finding better drugs. Although recent years have brought new clinical trials, these are few and lack diversity in terms of drug mechanism of action, thus resulting in a weak drug discovery pipeline. This fragility has been recently exposed by the failure of two candidates; posaconazole and E1224, to sterilely cure patients in phase 2 clinical trials. Such setbacks highlight the need for continuous, novel and high quality drug discovery and development efforts to discover better and safer treatments. In this article we will review past and current findings on drug discovery for Trypanosoma cruzi made by academic research groups, industry and other research organizations over the last half century. We also analyze the current research landscape that is now better placed than ever to deliver alternative treatments for Chagas disease in the near future.

Authors: L. Gaspar, C. B. Moraes, L. H. Freitas-Junior, S. Ferrari, L. Costantino, M. P. Costi, R. P. Coron, T. K. Smith, J. L. Siqueira-Neto, J. H. McKerrow, A. Cordeiro-da-Silva

Date Published: 20th Oct 2015

Publication Type: Journal

cy3sabiork: A Cytoscape app for visualizing kinetic data from SABIO-RK

Abstract (Expand)

Kinetic data of biochemical reactions are essential for the creation of kinetic models of biochemical networks. One of the main resources of such information is SABIO-RK, a curated database for kinetic … data of biochemical reactions and their related information. Despite the importance for computational modelling there has been no simple solution to visualize the kinetic data from SABIO-RK. In this work, I present cy3sabiork, an app for querying and visualization of kinetic data from SABIO-RK in Cytoscape. The kinetic information is accessible via a combination of graph structure and annotations of nodes, with provided information consisting of: (I) reaction details, enzyme and organism; (II) kinetic law, formula, parameters; (III) experimental conditions; (IV) publication; (V) additional annotations. cy3sabiork creates an intuitive visualization of kinetic entries in form of a species-reaction-kinetics graph, which reflects the reaction-centered approach of SABIO-RK. Kinetic entries can be imported in SBML format from either the SABIO-RK web interface or via web service queries. The app allows for easy comparison of kinetic data, visual inspection of the elements involved in the kinetic record and simple access to the annotation information of the kinetic record. I applied cy3sabiork in the computational modelling of galactose metabolism in the human liver.

Author: Matthias König

Date Published: 2016

Publication Type: Not specified

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