@article {2598, title = {Validated In Silico Model for Biofilm Formation in Escherichia coli [Bugworks Research Pvt. Ltd., a C-CAMP Startup]}, journal = {ACS Synthetic Biology}, year = {2022}, month = {01/2022}, abstract = {

Using\ Escherichia coli\ as the representative biofilm former, we report here the development of an in silico model built by simulating events that transform a free-living bacterial entity into self-encased multicellular biofilms. Published literature on \~{}300 genes associated with pathways involved in biofilm formation was curated, static maps were created, and suitably interconnected with their respective metabolites using ordinary differential equations. Precise interplay of genetic networks that regulate the transitory switching of bacterial growth pattern in response to environmental changes and the resultant multicomponent synthesis of the extracellular matrix were appropriately represented. Subsequently, the in silico model was analyzed by simulating time-dependent changes in the concentration of components by using the R and python environment. The model was validated by simulating and verifying the impact of key gene knockouts (KOs) and systematic knockdowns on biofilm formation, thus ensuring the outcomes were comparable with the reported literature. Similarly, specific gene KOs in laboratory and pathogenic\ E. coli\ were constructed and assessed. MiaA, YdeO, and YgiV were found to be crucial in biofilm development. Furthermore, qRT-PCR confirmed the elevation of expression in biofilm-forming clinical isolates. Findings reported in this study offer opportunities for identifying biofilm inhibitors with applications in multiple industries. The application of this model can be extended to the health care sector specifically to develop novel adjunct therapies that prevent biofilms in medical implants and reduce emergence of biofilm-associated resistant polymicrobial-chronic infections. The in silico framework reported here is open source and accessible for further enhancements.

}, doi = {10.1021/acssynbio.1c00445}, url = {https://doi.org/10.1021/acssynbio.1c00445}, author = {Bhowmik, Purnendu and Rajagopal, Sreenath and Hmar, Rothangamawi Victoria and Singh, Purnima and Saxena, Pragya and Amar, Prakruthi and Thomas, Teby and Ravishankar, Rajani and Nagaraj, Savitha and Katagihallimath, Nainesh and Sarangapani, Ramanujan Kadambi and Ramachandran, Vasanthi and Datta, Santanu} } @article {868, title = {A versatile LC-MS/MS approach for comprehensive, quantitative analysis of central metabolic pathways. [Mass Spectrometry - Lipidomics \& Metabolomics (INT)]}, journal = {Wellcome Open Res}, volume = {3}, year = {2018}, month = {2018}, pages = {122}, abstract = {

Liquid chromatography-mass spectrometry (LC-MS/MS) based approaches are widely used for the identification and quantitation of specific metabolites, and are a preferred approach towards analyzing cellular metabolism. Most methods developed come with specific requirements such as unique columns, ion-pairing reagents and pH conditions, and typically allow measurements in a specific pathway alone. Here, we present a single column-based set of methods for simultaneous coverage of multiple pathways, primarily focusing on central carbon, amino acid, and nucleotide metabolism. We further demonstrate the use of this method for quantitative, stable isotope-based metabolic flux experiments, expanding its use beyond steady-state level measurements of metabolites. The expected kinetics of label accumulation pertinent to the pathway under study are presented with some examples. The methods discussed here are broadly applicable, minimize the need for multiple chromatographic resolution methods, and highlight how simple labeling experiments can be valuable in facilitating a comprehensive understanding of the metabolic state of cells.

}, issn = {2398-502X}, doi = {10.12688/wellcomeopenres.14832.1}, author = {Walvekar, Adhish and Rashida, Zeenat and Maddali, Hemanth and Laxman, Sunil} } @article {518, title = {Vertebrate Hedgehog is secreted on two types of extracellular vesicles with different signaling properties. (Mass spectrometry - Proteomics)}, journal = {Sci Rep}, volume = {4}, year = {2014}, month = {2014 Dec 08}, pages = {7357}, abstract = {

Hedgehog (Hh) is a secreted morphogen that elicits differentiation and patterning in developing tissues. Multiple proposed mechanisms to regulate Hh dispersion includes lipoprotein particles and exosomes. Here we report that vertebrate Sonic Hedgehog (Shh) is secreted on two types of extracellular-vesicles/exosomes, from human cell lines and primary chick notochord cells. Although largely overlapping in size as estimated from electron micrographs, the two exosomal fractions exhibited distinct protein and RNA composition. We have probed the functional properties of these vesicles using cell-based assays of Hh-elicited gene expression. Our results suggest that while both Shh-containing exo-vesicular fractions can activate an ectopic Gli-luciferase construct, only exosomes co-expressing Integrins can activate endogenous Shh target genes HNF3β and Olig2 during the differentiation of mouse ES cells to ventral neuronal progenitors. Taken together, our results demonstrate that primary vertebrate cells secrete Shh in distinct vesicular forms, and support a model where packaging of Shh along with other signaling proteins such as Integrins on exosomes modulates target gene activation. The existence of distinct classes of Shh-containing exosomes also suggests a previously unappreciated complexity for fine-tuning of Shh-mediated gradients and pattern formation.

}, keywords = {Animals, Chick Embryo, Exosomes, Extracellular Space, Hedgehog Proteins, HEK293 Cells, Humans, MicroRNAs, Models, Biological, Protein Transport, Signal Transduction, Vertebrates}, issn = {2045-2322}, doi = {10.1038/srep07357}, author = {Vyas, Neha and Walvekar, Ankita and Tate, Dhananjay and Lakshmanan, Vairavan and Bansal, Dhiru and Lo Cicero, Alessandra and Raposo, Graca and Palakodeti, Dasaradhi and Dhawan, Jyotsna} }