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626 Publications visible to you, out of a total of 626
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

Metabolic model of central carbon and energy metabolisms of growing Arabidopsis thaliana in relation to sucrose translocation

Abstract (Expand)

Sucrose translocation between plant tissues is crucial for growth, development and reproduction of plants. Systemic analysis of these metabolic and underlying regulatory processes allow a detailed … understanding of carbon distribution within the plant and the formation of associated phenotypic traits. Sucrose translocation from ‘source’ tissues (e.g. mesophyll) to ‘sink’ tissues (e.g. root) is tightly bound to the proton gradient across the membranes. The plant sucrose transporters are grouped into efflux exporters (SWEET family) and proton-symport importers (SUC, STP families). To better understand regulation of sucrose export from source tissues and sucrose import into sink tissues, there is a need for a metabolic model that takes in account the tissue organisation of Arabidopsis thaliana with corresponding metabolic specificities of respective tissues in terms of sucrose and proton production/utilization. An ability of the model to operate under different light modes (‘light’ and ‘dark’) and correspondingly in different energy producing modes is particularly important in understanding regulatory modules.

Authors: Maksim Zakhartsev, Irina Medvedeva, Yury Orlov, Ilya Akberdin, Olga Krebs, Waltraud X. Schulze

Date Published: 1st Dec 2016

Publication Type: Journal

A systems study reveals concurrent activation of AMPK and mTOR by amino acids.

Abstract (Expand)

Amino acids (aa) are not only building blocks for proteins, but also signalling molecules, with the mammalian target of rapamycin complex 1 (mTORC1) acting as a key mediator. However, little is known … about whether aa, independently of mTORC1, activate other kinases of the mTOR signalling network. To delineate aa-stimulated mTOR network dynamics, we here combine a computational-experimental approach with text mining-enhanced quantitative proteomics. We report that AMP-activated protein kinase (AMPK), phosphatidylinositide 3-kinase (PI3K) and mTOR complex 2 (mTORC2) are acutely activated by aa-readdition in an mTORC1-independent manner. AMPK activation by aa is mediated by Ca(2+)/calmodulin-dependent protein kinase kinase beta (CaMKKbeta). In response, AMPK impinges on the autophagy regulators Unc-51-like kinase-1 (ULK1) and c-Jun. AMPK is widely recognized as an mTORC1 antagonist that is activated by starvation. We find that aa acutely activate AMPK concurrently with mTOR. We show that AMPK under aa sufficiency acts to sustain autophagy. This may be required to maintain protein homoeostasis and deliver metabolite intermediates for biosynthetic processes.

Authors: P. Dalle Pezze, S. Ruf, A. G. Sonntag, M. Langelaar-Makkinje, P. Hall, A. M. Heberle, P. Razquin Navas, K. van Eunen, R. C. Tolle, J. J. Schwarz, H. Wiese, B. Warscheid, J. Deitersen, B. Stork, E. Fassler, S. Schauble, U. Hahn, P. Horvatovich, D. P. Shanley, K. Thedieck

Date Published: 21st Nov 2016

Publication Type: Journal

NAD + Replenishment Improves Lifespan and Healthspan in Ataxia Telangiectasia Models via Mitophagy and DNA Repair

Abstract (Expand)

Ataxia telangiectasia (A-T) is a rare autosomal recessive disease characterized by progressive neurodegeneration and cerebellar ataxia. A-T is causally linked to defects in ATM, a master regulator of … the response to and repair of DNA double-strand breaks. The molecular basis of cerebellar atrophy and neurodegeneration in A-T patients is unclear. Here we report and examine the significance of increased PARylation, low NAD+, and mitochondrial dysfunction in ATM-deficient neurons, mice, and worms. Treatments that replenish intracellular NAD+ reduce the severity of A-T neuropathology, normalize neuromuscular function, delay memory loss, and extend lifespan in both animal models. Mechanistically, treatments that increase intracellular NAD+ also stimulate neuronal DNA repair and improve mitochondrial quality via mitophagy. This work links two major theories on aging, DNA damage accumulation, and mitochondrial dysfunction through nuclear DNA damage-induced nuclear-mitochondrial signaling, and demonstrates that they are important pathophysiological determinants in premature aging of A-T, pointing to therapeutic interventions.

Authors: Evandro Fei Fang, Henok Kassahun, Deborah L. Croteau, Morten Scheibye-Knudsen, Krisztina Marosi, Huiming Lu, Raghavendra A. Shamanna, Sumana Kalyanasundaram, Ravi Chand Bollineni, Mark A. Wilson, Wendy B. Iser, Bradley N. Wollman, Marya Morevati, Jun Li, Jesse S. Kerr, Qiping Lu, Tyler B. Waltz, Jane Tian, David A. Sinclair, Mark P. Mattson, Hilde Nilsen, Vilhelm A. Bohr

Date Published: 1st Oct 2016

Publication Type: Not specified

A systems biology approach reveals major metabolic changes in the thermoacidophilic archaeon Sulfolobus solfataricus in response to the carbon source L-fucose versus D-glucose

Abstract (Expand)

Archaea are characterised by a complex metabolism with many unique enzymes that differ from their bacterial and eukaryotic counterparts. The thermoacidophilic archaeon Sulfolobus solfataricus is known … for its metabolic versatility and is able to utilize a great variety of different carbon sources. However, the underlying degradation pathways and their regulation are often unknown. In this work, we analyse growth on different carbon sources using an integrated systems biology approach. The comparison of growth on L-fucose and D-glucose allows first insights into the genome-wide changes in response to the two carbon sources and revealed a new pathway for L-fucose degradation in S. solfataricus. During growth on L-fucose we observed major changes in the central carbon metabolic network, as well as an increased activity of the glyoxylate bypass and the 3-hydroxypropionate/4-hydroxybutyrate cycle. Within the newly discovered pathway for L-fucose degradation the following key reactions were identified: (i) L-fucose oxidation to L-fuconate via a dehydrogenase, (ii) dehydration to 2-keto-3-deoxy-L-fuconate via dehydratase, (iii) 2-keto-3-deoxy-L-fuconate cleavage to pyruvate and L-lactaldehyde via aldolase and (iv) L-lactaldehyde conversion to L-lactate via aldehyde dehydrogenase. This pathway as well as L-fucose transport shows interesting overlaps to the D-arabinose pathway, representing another example for pathway promiscuity in Sulfolobus species. This article is protected by copyright. All rights reserved.

Authors: J. Wolf, H. Stark, K. Fafenrot, A. Albersmeier, T. K. Pham, K. B. Muller, B. Meyer, L. Hoffmann, L. Shen, S. P. Albaum, T. Kouril, K. Schmidt-Hohagen, M. Neumann-Schaal, C. Brasen, J. Kalinowski, P. C. Wright, S. V. Albers, D. Schomburg, B. Siebers

Date Published: 10th Sep 2016

Publication Type: Not specified

L1 regularization facilitates detection of cell type-specific parameters in dynamical systems

Abstract (Expand)

MOTIVATION: A major goal of drug development is to selectively target certain cell types. Cellular decisions influenced by drugs are often dependent on the dynamic processing of information. Selective … responses can be achieved by differences between the involved cell types at levels of receptor, signaling, gene regulation or further downstream. Therefore, a systematic approach to detect and quantify cell type-specific parameters in dynamical systems becomes necessary. RESULTS: Here, we demonstrate that a combination of nonlinear modeling with L1 regularization is capable of detecting cell type-specific parameters. To adapt the least-squares numerical optimization routine to L1 regularization, sub-gradient strategies as well as truncation of proposed optimization steps were implemented. Likelihood-ratio tests were used to determine the optimal regularization strength resulting in a sparse solution in terms of a minimal number of cell type-specific parameters that is in agreement with the data. By applying our implementation to a realistic dynamical benchmark model of the DREAM6 challenge we were able to recover parameter differences with an accuracy of 78%. Within the subset of detected differences, 91% were in agreement with their true value. Furthermore, we found that the results could be improved using the profile likelihood. In conclusion, the approach constitutes a general method to infer an overarching model with a minimum number of individual parameters for the particular models. AVAILABILITY AND IMPLEMENTATION: A MATLAB implementation is provided within the freely available, open-source modeling environment Data2Dynamics. Source code for all examples is provided online at http://www.data2dynamics.org/ CONTACT: bernhard.steiert@fdm.uni-freiburg.de.

Authors: B. Steiert, J. Timmer, C. Kreutz

Date Published: 3rd Sep 2016

Publication Type: Not specified

Driving the Model to Its Limit: Profile Likelihood Based Model Reduction

Abstract (Expand)

In systems biology, one of the major tasks is to tailor model complexity to information content of the data. A useful model should describe the data and produce well-determined parameter estimates and … predictions. Too small of a model will not be able to describe the data whereas a model which is too large tends to overfit measurement errors and does not provide precise predictions. Typically, the model is modified and tuned to fit the data, which often results in an oversized model. To restore the balance between model complexity and available measurements, either new data has to be gathered or the model has to be reduced. In this manuscript, we present a data-based method for reducing non-linear models. The profile likelihood is utilised to assess parameter identifiability and designate likely candidates for reduction. Parameter dependencies are analysed along profiles, providing context-dependent suggestions for the type of reduction. We discriminate four distinct scenarios, each associated with a specific model reduction strategy. Iterating the presented procedure eventually results in an identifiable model, which is capable of generating precise and testable predictions. Source code for all toy examples is provided within the freely available, open-source modelling environment Data2Dynamics based on MATLAB available at http://www.data2dynamics.org/, as well as the R packages dMod/cOde available at https://github.com/dkaschek/. Moreover, the concept is generally applicable and can readily be used with any software capable of calculating the profile likelihood.

Authors: T. Maiwald, H. Hass, B. Steiert, J. Vanlier, R. Engesser, A. Raue, F. Kipkeew, H. H. Bock, D. Kaschek, C. Kreutz, J. Timmer

Date Published: 3rd Sep 2016

Publication Type: Not specified

Translational Targeted Proteomics Profiling of Mitochondrial Energy Metabolic Pathways in Mouse and Human Samples.

Abstract (Expand)

Absolute measurements of protein abundance are important in the understanding of biological processes and the precise computational modeling of biological pathways. We developed targeted LC-MS/MS assays … in the selected reaction monitoring (SRM) mode to quantify over 50 mitochondrial proteins in a single run. The targeted proteins cover the tricarboxylic acid cycle, fatty acid beta-oxidation, oxidative phosphorylation, and the detoxification of reactive oxygen species. Assays used isotopically labeled concatemers as internal standards designed to target murine mitochondrial proteins and their human orthologues. Most assays were also suitable to quantify the corresponding protein orthologues in rats. After exclusion of peptides that did not pass the selection criteria, we arrived at SRM assays for 55 mouse, 52 human, and 51 rat proteins. These assays were optimized in isolated mitochondrial fractions from mouse and rat liver and cultured human fibroblasts and in total liver extracts from mouse, rat, and human. The developed proteomics approach is suitable for the quantification of proteins in the mitochondrial energy metabolic pathways in mice, rats, and humans as a basis for translational research. Initial data show that the assays have great potential for elucidating the adaptive response of human patients to mutations in mitochondrial proteins in a clinical setting.

Authors: J. C. Wolters, J. Ciapaite, K. van Eunen, K. E. Niezen-Koning, A. Matton, R. J. Porte, P. Horvatovich, B. M. Bakker, R. Bischoff, H. P. Permentier

Date Published: 2nd Sep 2016

Publication Type: Journal

Profiling of Flavonol Derivatives for the Development of Antitrypanosomatidic Drugs.

Abstract (Expand)

Flavonoids represent a potential source of new antitrypanosomatidic leads. Starting from a library of natural products, we combined target-based screening on pteridine reductase 1 with phenotypic … screening on Trypanosoma brucei for hit identification. Flavonols were identified as hits, and a library of 16 derivatives was synthesized. Twelve compounds showed EC50 values against T. brucei below 10 muM. Four X-ray crystal structures and docking studies explained the observed structure-activity relationships. Compound 2 (3,6-dihydroxy-2-(3-hydroxyphenyl)-4H-chromen-4-one) was selected for pharmacokinetic studies. Encapsulation of compound 2 in PLGA nanoparticles or cyclodextrins resulted in lower in vitro toxicity when compared to the free compound. Combination studies with methotrexate revealed that compound 13 (3-hydroxy-6-methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one) has the highest synergistic effect at concentration of 1.3 muM, 11.7-fold dose reduction index and no toxicity toward host cells. Our results provide the basis for further chemical modifications aimed at identifying novel antitrypanosomatidic agents showing higher potency toward PTR1 and increased metabolic stability.

Authors: C. Borsari, R. Luciani, C. Pozzi, I. Poehner, S. Henrich, M. Trande, A. Cordeiro-da-Silva, N. Santarem, C. Baptista, A. Tait, F. Di Pisa, L. Dello Iacono, G. Landi, S. Gul, M. Wolf, M. Kuzikov, B. Ellinger, J. Reinshagen, G. Witt, P. Gribbon, M. Kohler, O. Keminer, B. Behrens, L. Costantino, P. Tejera Nevado, E. Bifeld, J. Eick, J. Clos, J. Torrado, M. D. Jimenez-Anton, M. J. Corral, J. M. Alunda, F. Pellati, R. C. Wade, S. Ferrari, S. Mangani, M. P. Costi

Date Published: 25th Aug 2016

Publication Type: Journal

Quantitative analyses of the hepatic proteome of methylmercury-exposed Atlantic cod (Gadus morhua) suggest oxidative stress-mediated effects on cellular energy metabolism

Abstract (Expand)

BACKGROUND: Methylmecury (MeHg) is a widely distributed environmental pollutant with considerable risk to both human health and wildlife. To gain better insight into the underlying mechanisms of … MeHg-mediated toxicity, we have used label-free quantitative mass spectrometry to analyze the liver proteome of Atlantic cod (Gadus morhua) exposed in vivo to MeHg (0, 0.5, 2 mg/kg body weight) for 2 weeks. RESULTS: Out of a toltal of 1143 proteins quantified, 125 proteins were differentially regulated between MeHg-treated samples and controls. Using various bioinformatics tools, we performed gene ontology, pathway and network enrichment analysis, which indicated that proteins and pathways mainly related to energy metabolism, antioxidant defense, cytoskeleton remodeling, and protein synthesis were regulated in the hepatic proteome after MeHg exposure. Comparison with previous gene expression data strengthened these results, and further supported that MeHg predominantly affects many energy metabolism pathways, presumably through its strong induction of oxidative stress. Some enzymes known to have functionally important oxidation-sensitive cysteine residues in other animals are among the differentially regulated proteins, suggesting their modulations by MeHg-induced oxidative stress. Integrated analysis of the proteomics dataset combined with previous gene expression dataset showed a more pronounced effect of MeHg on amino acid, glucose and fatty acid metabolic pathways, and suggested possible interactions of the cellular energy metabolism and antioxidant defense pathways. CONCLUSIONS: MeHg disrupts mainly redox homeostasis and energy generating metabolic pathways in cod liver. The energy pathways appear to be modulated through MeHg-induced oxidative stress, possibly mediated by oxidation sensitive enzymes.

Authors: F. Yadetie, S. Bjorneklett, H. K. Garberg, E. Oveland, F. Berven, A. Goksoyr, O. A. Karlsen

Date Published: 9th Aug 2016

Publication Type: Not specified

Identification of Cell Type-Specific Differences in Erythropoietin Receptor Signaling in Primary Erythroid and Lung Cancer Cells.

Abstract (Expand)

Lung cancer, with its most prevalent form non-small-cell lung carcinoma (NSCLC), is one of the leading causes of cancer-related deaths worldwide, and is commonly treated with chemotherapeutic drugs … such as cisplatin. Lung cancer patients frequently suffer from chemotherapy-induced anemia, which can be treated with erythropoietin (EPO). However, studies have indicated that EPO not only promotes erythropoiesis in hematopoietic cells, but may also enhance survival of NSCLC cells. Here, we verified that the NSCLC cell line H838 expresses functional erythropoietin receptors (EPOR) and that treatment with EPO reduces cisplatin-induced apoptosis. To pinpoint differences in EPO-induced survival signaling in erythroid progenitor cells (CFU-E, colony forming unit-erythroid) and H838 cells, we combined mathematical modeling with a method for feature selection, the L1 regularization. Utilizing an example model and simulated data, we demonstrated that this approach enables the accurate identification and quantification of cell type-specific parameters. We applied our strategy to quantitative time-resolved data of EPO-induced JAK/STAT signaling generated by quantitative immunoblotting, mass spectrometry and quantitative real-time PCR (qRT-PCR) in CFU-E and H838 cells as well as H838 cells overexpressing human EPOR (H838-HA-hEPOR). The established parsimonious mathematical model was able to simultaneously describe the data sets of CFU-E, H838 and H838-HA-hEPOR cells. Seven cell type-specific parameters were identified that included for example parameters for nuclear translocation of STAT5 and target gene induction. Cell type-specific differences in target gene induction were experimentally validated by qRT-PCR experiments. The systematic identification of pathway differences and sensitivities of EPOR signaling in CFU-E and H838 cells revealed potential targets for intervention to selectively inhibit EPO-induced signaling in the tumor cells but leave the responses in erythroid progenitor cells unaffected. Thus, the proposed modeling strategy can be employed as a general procedure to identify cell type-specific parameters and to recommend treatment strategies for the selective targeting of specific cell types.

Authors: R. Merkle, B. Steiert, F. Salopiata, S. Depner, A. Raue, N. Iwamoto, M. Schelker, H. Hass, M. Wasch, M. E. Bohm, O. Mucke, D. B. Lipka, C. Plass, W. D. Lehmann, C. Kreutz, J. Timmer, M. Schilling, U. Klingmuller

Date Published: 6th Aug 2016

Publication Type: Journal

SARS and MERS: recent insights into emerging coronaviruses

Abstract (Expand)

The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 marked the second introduction of a highly pathogenic coronavirus into the human population in the twenty-first century. … The continuing introductions of MERS-CoV from dromedary camels, the subsequent travel-related viral spread, the unprecedented nosocomial outbreaks and the high case-fatality rates highlight the need for prophylactic and therapeutic measures. Scientific advancements since the 2002–2003 severe acute respiratory syndrome coronavirus (SARS-CoV) pandemic allowed for rapid progress in our understanding of the epidemiology and pathogenesis of MERS-CoV and the development of therapeutics. In this Review, we detail our present understanding of the transmission and pathogenesis of SARS-CoV and MERS-CoV, and discuss the current state of development of measures to combat emerging coronaviruses.

Authors: Emmie de Wit, Neeltje van Doremalen, Darryl Falzarano, Vincent J. Munster

Date Published: 1st Aug 2016

Publication Type: Journal

Photoreceptor effects on plant biomass, resource allocation, and metabolic state

Abstract (Expand)

Plants sense the light environment through an ensemble of photoreceptors. Members of the phytochrome class of light receptors are known to play a critical role in seedling establishment, and are among … the best-characterized plant signaling components. Phytochromes also regulate adult plant growth; however, our knowledge of this process is rather fragmented. This study demonstrates that phytochrome controls carbon allocation and biomass production in the developing plant. Phytochrome mutants have a reduced CO2 uptake, yet overaccumulate daytime sucrose and starch. This finding suggests that even though carbon fixation is impeded, the available carbon resources are not fully used for growth during the day. Supporting this notion, phytochrome depletion alters the proportion of day:night growth. In addition, phytochrome loss leads to sizeable reductions in overall growth, dry weight, total protein levels, and the expression of CELLULOSE SYNTHASE-LIKE genes. Because cellulose and protein are major constituents of plant biomass, our data point to an important role for phytochrome in regulating these fundamental components of plant productivity. We show that phytochrome loss impacts core metabolism, leading to elevated levels of tricarboxylic acid cycle intermediates, amino acids, sugar derivatives, and notably the stress metabolites proline and raffinose. Furthermore, the already growth-retarded phytochrome mutants are less responsive to growth-inhibiting abiotic stresses and have elevated expression of stress marker genes. This coordinated response appears to divert resources from energetically costly biomass production to improve resilience. In nature, this strategy may be activated in phytochrome-disabling, vegetation-dense habitats to enhance survival in potentially resource-limiting conditions.

Authors: Deyue Yang, Daniel D. Seaton, Johanna Krahmer, Karen J. Halliday

Date Published: 5th Jul 2016

Publication Type: Not specified

Toward community standards and software for whole-cell modeling

Abstract (Expand)

Whole-cell (WC) modeling is a promising tool for biological research, bioengineering, and medicine. However, substantial work remains to create accurate, comprehensive models of complex cells. METHODS: … We organized the 2015 Whole-Cell Modeling Summer School to teach WC modeling and evaluate the need for new WC modeling standards and software by recoding a recently published WC model in SBML. RESULTS: Our analysis revealed several challenges to representing WC models using the current standards. CONCLUSION: We, therefore, propose several new WC modeling standards, software, and databases. SIGNIFICANCE: We anticipate that these new standards and software will enable more comprehensive models.

Authors: D. Waltemath, J. Karr, F. Bergmann, V. Chelliah, M. Hucka, M. Krantz, W. Liebermeister, P. Mendes, C. Myers, P. Pir, B. Alaybeyoglu, N. Aranganathan, K. Baghalian, A. Bittig, P. Burke, M. Cantarelli, Y. Chew, R. Costa, J. Cursons, T. Czauderna, A. Goldberg, H. Gomez, J. Hahn, T. Hameri, D. Gardiol, D. Kazakiewicz, I. Kiselev, V. Knight-Schrijver, C. Knupfer, M. Konig, D. Lee, A. Lloret-Villas, N. Mandrik, J. Medley, B. Moreau, H. Naderi-Meshkin, S. Palaniappan, D. Priego-Espinosa, M. Scharm, M. Sharma, K. Smallbone, N. Stanford, J. H. Song, T. Theile, M. Tokic, N. Tomar, V. Toure, J. Uhlendorf, T. Varusai, L. Watanabe, F. Wendland, M. Wolfien, J. Yurkovich, Y. Zhu, A. Zardilis, A. Zhukova, F. Schreiber

Date Published: 16th Jun 2016

Publication Type: Not specified

Formation of xylitol and xylitol-5-phosphate and its impact on growth of d-xylose-utilizing Corynebacterium glutamicum strains

Abstract (Expand)

Wild-type Corynebacterium glutamicum has no endogenous metabolic activity for utilizing the lignocellulosic pentose d-xylose for cell growth. Therefore, two different engineering approaches have been … pursued resulting in platform strains harbouring a functional version of either the Isomerase (ISO) or the Weimberg (WMB) pathway for d-xylose assimilation. In a previous study we found for C. glutamicum WMB by-product formation of xylitol during growth on d-xylose and speculated that the observed lower growth rates are due to the growth inhibiting effect of this compound. Based on a detailed phenotyping of the ISO, WMB and the wild-type strain of C. glutamicum, we here show that this organism has a natural capability to synthesize xylitol from d-xylose under aerobic cultivation conditions. We furthermore observed the intracellular accumulation of xylitol-5-phosphate as a result of the intracellular phosphorylation of xylitol, which was particularly pronounced in the C. glutamicum ISO strain. Interestingly, low amounts of supplemented xylitol strongly inhibit growth of this strain on d-xylose, d-glucose and d-arabitol. These findings demonstrate that xylitol is a suitable substrate of the endogenous xylulokinase (XK, encoded by xylB) and its overexpression in the ISO strain leads to a significant phosphorylation of xylitol in C. glutamicum. Therefore, in order to circumvent cytotoxicity by xylitol-5-phosphate, the WMB pathway represents an interesting alternative route for engineering C. glutamicum towards efficient d-xylose utilization.

Authors: A. Radek, M. F. Muller, J. Gatgens, L. Eggeling, K. Krumbach, J. Marienhagen, S. Noack

Date Published: 15th Jun 2016

Publication Type: Not specified

Principles of Virus Uncoating: Cues and the Snooker Ball

Abstract (Expand)

The architecture of a virus particle allows timely release of the viral genome in a host cell during entry. This critical step is known as viral uncoating. It is regulated by cues from receptors, enzymes … and chemicals, and facilitated by factors that do not contact the virion directly. This review covers a wide range of cellular processes that enhance viral uncoating. The underlying mechanisms provide deep insights into cell biological and immunological processes of virus–host interactions and infections.

Authors: Yohei Yamauchi, Urs F. Greber

Date Published: 1st Jun 2016

Publication Type: Journal

Transcriptomic analysis reveals how a lack of potassium ions increases Sulfolobus acidocaldarius sensitivity to pH changes

Abstract

Not specified

Authors: Antoine Buetti-Dinh, Olga Dethlefsen, Ran Friedman, Mark Dopson

Date Published: 26th May 2016

Publication Type: Not specified

Molecular biological correlation of fluorine-18 fluorodeoxyglucose uptake in esophageal squamous cell carcinoma

Abstract (Expand)

OBJECTIVE: The aim of this study was to assess the relationship between fluorine-18 fluorodeoxyglucose (F-FDG) uptake and molecular biological markers in esophageal squamous cell carcinoma (ESCC) … patients. METHODS: Our patient population included 51 patients who underwent F-FDG PET/computed tomography before surgery. Excised tumor tissue was analyzed immunohistochemically using monoclonal antibodies for glucose transporter-1 (GLUT-1), GLUT-3, CD34 [microvessel density (MVD) marker], CD68 (macrophage marker), and CD163 (tumor-associated macrophage marker). The relationships among pathological factors [pathological T stage (p-T stage), pathological lymph node status (p-N status), pathological stage (p-stage), and pathological tumor length], the maximum standardized uptake value (SUVmax), and these molecular biological markers were evaluated using Spearman's rank test and the Kruskal-Wallis test. RESULTS: GLUT-1, GLUT-3, CD34, and CD163 significantly correlated with SUVmax (r=0.547, P<0.001 for GLUT-1; r=0.569, P<0.001 for GLUT-3; r=0.463, P=0.001 for CD34, r=0.455, P=0.001 for CD163), whereas SUVmax, GLUT-1, GLUT-3, CD34, and CD163 significantly correlated with p-T stage (r=0.552, P<0.001 for SUVmax, r=0.307, P=0.03 for GLUT-1, r=0.349, P=0.013 for GLUT-3, r=0.313, P=0.027 for CD34, r=0.526 for CD163, P<0.001), but not with p-N status. CD68 levels showed no significant correlation with SUVmax, p-T stage, p-stage, or p-N status. CONCLUSION: SUVmax, GLUT-1 expression, GLUT-3 expression, MVD, and TAMs show a relationship with the tumor stage and extent of ESCC. GLUT-1, GLUT-3, MVD, and TAMs are associated with the mechanism of F-FDG uptake in ESCC.

Authors: Y. Hirose, H. Kaida, A. Kawahara, S. Matono, T. Tanaka, S. Kurata, M. Kage, M. Ishibashi, T. Abe

Date Published: 25th May 2016

Publication Type: Not specified

Hedgehog signaling is a potent regulator of liver lipid metabolism and reveals a GLI-code associated with steatosis

Abstract (Expand)

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in industrialized countries and is increasing in prevalence. The pathomechanisms, however, are poorly understood. This study … assessed the unexpected role of the Hedgehog pathway in adult liver lipid metabolism. Using transgenic mice with conditional hepatocyte-specific deletion of Smoothened in adult mice, we showed that hepatocellular inhibition of Hedgehog signaling leads to steatosis by altering the abundance of the transcription factors GLI1 and GLI3. This steatotic 'Gli-code' caused the modulation of a complex network of lipogenic transcription factors and enzymes, including SREBP1 and PNPLA3, as demonstrated by microarray analysis and siRNA experiments and could be confirmed in other steatotic mouse models as well as in steatotic human livers. Conversely, activation of the Hedgehog pathway reversed the "Gli-code" and mitigated hepatic steatosis. Collectively, our results reveal that dysfunctions in the Hedgehog pathway play an important role in hepatic steatosis and beyond.

Authors: Madlen Matz-Soja, Christiane Rennert, Kristin Schönefeld, Susanne Aleithe, Jan Boettger, Wolfgang Schmidt-Heck, Thomas S Weiss, Amalya Hovhannisyan, Sebastian Zellmer, Nora Klöting, Angela Schulz, Jürgen Kratzsch, Reinhardt Guthke, Rolf Gebhardt

Date Published: 17th May 2016

Publication Type: Not specified

Parallel DNA Polymerase Chain Reaction (PD-PCR)

Abstract (Expand)

This protocol describe an approach in which the first primer binds in a parallel complementary orientation to the single-stranded DNA, leading to synthesis in a parallel direction. Further reactions … happened in a conventional way leading to the synthesis of PCR product having polarity opposite to the template used. Here in FAIRDOM we use this SOP as an example/template

Authors: vikash bhardwaj, Vikash bhardwaj, Kulbhushan Sharma

Date Published: 5th May 2016

Publication Type: Journal

The Atlantic salmon genome provides insights into rediploidization

Abstract (Expand)

The whole-genome duplication 80 million years ago of the common ancestor of salmonids (salmonid-specific fourth vertebrate whole-genome duplication, Ss4R) provides unique opportunities to learn about … the evolutionary fate of a duplicated vertebrate genome in 70 extant lineages. Here we present a high-quality genome assembly for Atlantic salmon (Salmo salar), and show that large genomic reorganizations, coinciding with bursts of transposon-mediated repeat expansions, were crucial for the post-Ss4R rediploidization process. Comparisons of duplicate gene expression patterns across a wide range of tissues with orthologous genes from a pre-Ss4R outgroup unexpectedly demonstrate far more instances of neofunctionalization than subfunctionalization. Surprisingly, we find that genes that were retained as duplicates after the teleost-specific whole-genome duplication 320 million years ago were not more likely to be retained after the Ss4R, and that the duplicate retention was not influenced to a great extent by the nature of the predicted protein interactions of the gene products. Finally, we demonstrate that the Atlantic salmon assembly can serve as a reference sequence for the study of other salmonids for a range of purposes.

Authors: S. Lien, B. F. Koop, S. R. Sandve, J. R. Miller, M. P. Kent, T. Nome, T. R. Hvidsten, J. S. Leong, D. R. Minkley, A. Zimin, F. Grammes, H. Grove, A. Gjuvsland, B. Walenz, R. A. Hermansen, K. von Schalburg, E. B. Rondeau, A. Di Genova, J. K. Samy, J. Olav Vik, M. D. Vigeland, L. Caler, U. Grimholt, S. Jentoft, D. Inge Vage, P. de Jong, T. Moen, M. Baranski, Y. Palti, D. R. Smith, J. A. Yorke, A. J. Nederbragt, A. Tooming-Klunderud, K. S. Jakobsen, X. Jiang, D. Fan, Y. Hu, D. A. Liberles, R. Vidal, P. Iturra, S. J. Jones, I. Jonassen, A. Maass, S. W. Omholt, W. S. Davidson

Date Published: 18th Apr 2016

Publication Type: Not specified

The Human Physiome: how standards, software and innovative service infrastructures are providing the building blocks to make it achievable

Abstract (Expand)

Reconstructing and understanding the Human Physiome virtually is a complex mathematical problem, and a highly demanding computational challenge. Mathematical models spanning from the molecular level … through to whole populations of individuals must be integrated, then personalized. This requires interoperability with multiple disparate and geographically separated data sources, and myriad computational software tools. Extracting and producing knowledge from such sources, even when the databases and software are readily available, is a challenging task. Despite the difficulties, researchers must frequently perform these tasks so that available knowledge can be continually integrated into the common framework required to realize the Human Physiome. Software and infrastructures that support the communities that generate these, together with their underlying standards to format, describe and interlink the corresponding data and computer models, are pivotal to the Human Physiome being realized. They provide the foundations for integrating, exchanging and re-using data and models efficiently, and correctly, while also supporting the dissemination of growing knowledge in these forms. In this paper, we explore the standards, software tooling, repositories and infrastructures that support this work, and detail what makes them vital to realizing the Human Physiome.

Authors: D. Nickerson, K. Atalag, B. de Bono, J. Geiger, C. Goble, S. Hollmann, J. Lonien, W. Muller, B. Regierer, N. J. Stanford, M. Golebiewski, P. Hunter

Date Published: 7th Apr 2016

Publication Type: Not specified

The FAIR Guiding Principles for scientific data management and stewardship.

Abstract (Expand)

There is an urgent need to improve the infrastructure supporting the reuse of scholarly data. A diverse set of stakeholders-representing academia, industry, funding agencies, and scholarly publishers-have … come together to design and jointly endorse a concise and measureable set of principles that we refer to as the FAIR Data Principles. The intent is that these may act as a guideline for those wishing to enhance the reusability of their data holdings. Distinct from peer initiatives that focus on the human scholar, the FAIR Principles put specific emphasis on enhancing the ability of machines to automatically find and use the data, in addition to supporting its reuse by individuals. This Comment is the first formal publication of the FAIR Principles, and includes the rationale behind them, and some exemplar implementations in the community.

Authors: M. D. Wilkinson, M. Dumontier, I. J. Aalbersberg, G. Appleton, M. Axton, A. Baak, N. Blomberg, J. W. Boiten, L. B. da Silva Santos, P. E. Bourne, J. Bouwman, A. J. Brookes, T. Clark, M. Crosas, I. Dillo, O. Dumon, S. Edmunds, C. T. Evelo, R. Finkers, A. Gonzalez-Beltran, A. J. Gray, P. Groth, C. Goble, J. S. Grethe, J. Heringa, P. A. 't Hoen, R. Hooft, T. Kuhn, R. Kok, J. Kok, S. J. Lusher, M. E. Martone, A. Mons, A. L. Packer, B. Persson, P. Rocca-Serra, M. Roos, R. van Schaik, S. A. Sansone, E. Schultes, T. Sengstag, T. Slater, G. Strawn, M. A. Swertz, M. Thompson, J. van der Lei, E. van Mulligen, J. Velterop, A. Waagmeester, P. Wittenburg, K. Wolstencroft, J. Zhao, B. Mons

Date Published: 15th Mar 2016

Publication Type: Journal

The FAIR Guiding Principles for scientific data management and stewardship

Abstract

Not specified

Authors: Mark D. Wilkinson, Michel Dumontier, IJsbrand Jan Aalbersberg, Gabrielle Appleton, Myles Axton, Arie Baak, Niklas Blomberg, Jan-Willem Boiten, Luiz Bonino da Silva Santos, Philip E. Bourne, Jildau Bouwman, Anthony J. Brookes, Tim Clark, Mercè Crosas, Ingrid Dillo, Olivier Dumon, Scott Edmunds, Chris T. Evelo, Richard Finkers, Alejandra Gonzalez-Beltran, Alasdair J.G. Gray, Paul Groth, Carole Goble, Jeffrey S. Grethe, Jaap Heringa, Peter A.C ’t Hoen, Rob Hooft, Tobias Kuhn, Ruben Kok, Joost Kok, Scott J. Lusher, Maryann E. Martone, Albert Mons, Abel L. Packer, Bengt Persson, Philippe Rocca-Serra, Marco Roos, Rene van Schaik, Susanna-Assunta Sansone, Erik Schultes, Thierry Sengstag, Ted Slater, George Strawn, Morris A. Swertz, Mark Thompson, Johan van der Lei, Erik van Mulligen, Jan Velterop, Andra Waagmeester, Peter Wittenburg, Katherine Wolstencroft, Jun Zhao, Barend Mons

Date Published: 15th Mar 2016

Publication Type: Not specified

Evaluation of GMP-compliant culture media for in vitro expansion of human bone marrow mesenchymal stromal cells.

Abstract (Expand)

Mesenchymal stromal cells (MSCs) from human bone marrow serve as a resource for cell-based therapies in regenerative medicine. Clinical applications require standardized protocols according to good … manufacturing practice (GMP) guidelines. Donor variability as well as the intrinsic heterogeneity of MSC populations must be taken into consideration. The composition of the culture medium is a key factor in successful MSC expansion. The aim of this study was to comparatively assess the efficiency of xeno-free human platelet lysate (HPL)-based cell expansion with two commercially available media-StemPro MSC SFM CTS (for human ex vivo tissue and cell culture processing applications) and MSCGM (non-GMP-compliant, for research only)-in an academic setting as the first optimization step toward GMP-compliant manufacturing. We report the feasibility of MSC expansion up to the yielded cell number with all three media. MSCs exhibited the typical fibroblastoid morphology, with distinct differences in cell size depending on the medium. The differentiation capacity and characteristic immunophenotype were confirmed for all MSC populations. Proliferation was highest using StemPro MSC SFM CTS, whereas HPL medium was more cost-effective and its composition could be adjusted individually according to the respective needs. In summary, we present a comprehensive evaluation of GMP-compatible culture media for MSC expansion. Both StemPro and HPL medium proved to be suitable for clinical application and allowed sufficient cell proliferation. Specific differences were observed and should be considered according to the intended use. This study provides a detailed cost analysis and tools that may be helpful for the establishment of GMP-compliant MSC expansion.

Authors: P. Wuchter, M. Vetter, R. Saffrich, A. Diehlmann, K. Bieback, A. D. Ho, P. Horn

Date Published: 26th Feb 2016

Publication Type: Journal

Microcavity arrays as an in vitro model system of the bone marrow niche for hematopoietic stem cells.

Abstract (Expand)

In previous studies human mesenchymal stromal cells (MSCs) maintained the "stemness" of human hematopoietic progenitor cells (HPCs) through direct cell-cell contact in two-dimensional co-culture … systems. We establish a three-dimensional (3D) co-culture system based on a custom-made chip, the 3(D)-KITChip, as an in vitro model system of the human hematopoietic stem cell niche. This array of up to 625 microcavities, with 300 mum size in each orientation, was inserted into a microfluidic bioreactor. The microcavities of the 3(D)-KITChip were inoculated with human bone marrow MSCs together with umbilical cord blood HPCs. MSCs used the microcavities as a scaffold to build a complex 3D mesh. HPCs were distributed three-dimensionally inside this MSC network and formed ss-catenin- and N-cadherin-based intercellular junctions to the surrounding MSCs. Using RT(2)-PCR and western blots, we demonstrate that a proportion of HPCs maintained the expression of CD34 throughout a culture period of 14 days. In colony-forming unit assays, the hematopoietic stem cell plasticity remained similar after 14 days of bioreactor co-culture, whereas monolayer co-cultures showed increasing signs of HPC differentiation and loss of stemness. These data support the notion that the 3D microenvironment created within the microcavity array preserves vital stem cell functions of HPCs more efficiently than conventional co-culture systems.

Authors: P. Wuchter, R. Saffrich, S. Giselbrecht, C. Nies, H. Lorig, S. Kolb, A. D. Ho, E. Gottwald

Date Published: 3rd Feb 2016

Publication Type: Journal

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

Targeting glycolysis in the malaria parasite Plasmodium falciparum

Abstract (Expand)

Glycolysis is the main pathway for ATP production in the malaria parasite Plasmodium falciparum and essential for its survival. Following a sensitivity analysis of a detailed kinetic model for glycolysis … in the parasite, the glucose transport reaction was identified as the step whose activity needed to be inhibited to the least extent to result in a 50% reduction in glycolytic flux. In a subsequent inhibitor titration with cytochalasin B, we confirmed the model analysis experimentally and measured a flux control coefficient of 0.3 for the glucose transporter. In addition to the glucose transporter, the glucokinase and phosphofructokinase had high flux control coefficients, while for the ATPase a small negative flux control coefficient was predicted. In a broader comparative analysis of glycolytic models, we identified a weakness in the P. falciparum pathway design with respect to stability towards perturbations in the ATP demand.

Authors: David D. van Niekerk, Gerald P. Penkler, Francois du Toit, Jacky L. Snoep

Date Published: 1st Feb 2016

Publication Type: Not specified

A molecular arms race between host innate antiviral response and emerging human coronaviruses

Abstract (Expand)

Coronaviruses have been closely related with mankind for thousands of years. Communityacquired human coronaviruses have long been recognized to cause common cold. However, zoonotic coronaviruses are … now becoming more a global concern with the discovery of highly pathogenic severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses causing severe respiratory diseases. Infections by these emerging human coronaviruses are characterized by less robust interferon production. Treatment of patients with recombinant interferon regimen promises beneficial outcomes, suggesting that compromised interferon expression might contribute at least partially to the severity of disease. The mechanisms by which coronaviruses evade host innate antiviral response are under intense investigations. This review focuses on the fierce arms race between host innate antiviral immunity and emerging human coronaviruses. Particularly, the host pathogen recognition receptors and the signal transduction pathways to mount an effective antiviral response against SARS and MERS coronavirus infection are discussed. On the other hand, the counter-measures evolved by SARS and MERS coronaviruses to circumvent host defense are also dissected. With a better understanding of the dynamic interaction between host and coronaviruses, it is hoped that insights on the pathogenesis of newly-identified highly pathogenic human coronaviruses and new strategies in antiviral development can be derived.

Authors: Lok-Yin Roy Wong, Pak-Yin Lui, Dong-Yan Jin

Date Published: 1st Feb 2016

Publication Type: Journal

Dysregulated Type I Interferon and Inflammatory Monocyte-Macrophage Responses Cause Lethal Pneumonia in SARS-CoV-Infected Mice

Abstract (Expand)

Highly pathogenic human respiratory coronaviruses cause acute lethal disease characterized by exuberant inflammatory responses and lung damage. However, the factors leading to lung pathology are not … well understood. Using mice infected with SARS (severe acute respiratory syndrome)-CoV, we show that robust virus replication accompanied by delayed type I interferon (IFN-I) signaling orchestrates inflammatory responses and lung immunopathology with diminished survival. IFN-I remains detectable until after virus titers peak, but early IFN-I administration ameliorates immunopathology. This delayed IFN-I signaling promotes the accumulation of pathogenic inflammatory monocytemacrophages (IMMs), resulting in elevated lung cytokine/chemokine levels, vascular leakage, and impaired virus-specific T cell responses. Genetic ablation of the IFN-ab receptor (IFNAR) or IMM depletion protects mice from lethal infection, without affecting viral load. These results demonstrate that IFN-I and IMM promote lethal SARS-CoV infection and identify IFN-I and IMMs as potential therapeutic targets in patients infected with pathogenic coronavirus and perhaps other respiratory viruses.

Authors: Rudragouda Channappanavar, Anthony R. Fehr, Rahul Vijay, Matthias Mack, Jincun Zhao, David K. Meyerholz, Stanley Perlman

Date Published: 1st Feb 2016

Publication Type: Journal

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