@article {9118, title = {Metabolic coupling of ROS generation and antioxidant synthesis by the GABA shunt pathway in myeloid-like blood progenitor cells of Drosophila. [CIFF \& Metabolomics Facility]}, journal = {PLoS Genet}, volume = {21}, year = {2025}, month = {2025 Sep}, pages = {e1011602}, abstract = {

Redox balance is crucial for normal development of stem and progenitor cells that reside in oxidative environments. In this study, we explore the mechanisms of redox homeostasis in such niches and show that myeloid-like blood progenitor cells of the Drosophila larval lymph gland, that generate reactive oxygen species (ROS), moderate it developmentally by de novo synthesizing glutathione (GSH) to ensure redox balance. During lymph gland development, as the blood-progenitor cells oxidize pyruvate via the TCA cycle leading to the generation of ROS, GABA-shunt restricts pyruvate dehydrogenase (PDH) activity and consequently TCA cycle flux. This moderation enables a metabolic rerouting of TCA-derived oxaloacetate (OAA) to pyruvate via gluconeogenesis, which is necessary to sustain serine levels, the rate-limiting precursor for de novo GSH synthesis. Disruption of GABA metabolism causes metabolic imbalance, marked by excessive PDH activity and heightened TCA cycle flux. This results in reduced OAA availability, impaired gluconeogenic capacity, and insufficient serine/GSH production, ultimately leading to ROS dysregulation. Overall, this study identifies a unique metabolic framework in blood progenitor cells, where the GABA shunt, by restraining PDH and TCA cycle activity, maintains ROS at developmental levels. By coupling TCA-derived metabolites to GSH production, this state enables the TCA cycle to support both ROS generation and ROS scavenging, ensuring the developmental roles of ROS while preserving progenitor homeostasis.

}, keywords = {Animals, Antioxidants, Citric Acid Cycle, Drosophila, Drosophila melanogaster, Drosophila Proteins, gamma-Aminobutyric Acid, Gluconeogenesis, Glutathione, Hematopoietic Stem Cells, Larva, Myeloid Cells, Oxidation-Reduction, Oxidative Stress, Pyruvic Acid, Reactive Oxygen Species}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1011602}, author = {Goyal, Manisha and Tiwari, Sakshi and Arora, Jagriti and Cooper, Bruce and Subramanian, Ramaswamy and Mukherjee, Tina} } @article {8356, title = {Lunatimonas lonarensis gen. nov., sp. nov., a haloalkaline bacterium of the family Cyclobacteriaceae with nitrate reducing activity [Next Gen Genomics Facility]}, journal = {Syst Appl Microbiol}, volume = {37}, year = {2014}, month = {2014 Feb}, pages = {10-6}, abstract = {

Novel pinkish-orange pigmented, Gram-negative staining, half-moon shaped, non-motile, strictly aerobic strains designated AK24(T) and AK26 were isolated from water and sediment samples of Lonar Lake, Buldhana district, Maharahstra, India. Both strains were positive for oxidase, catalase and β-galactosidase activities. The predominant fatty acids were iso-C15:0 (41.5\%), anteiso-C15:0 (9.7\%), iso-C17:0 3OH (9.6\%), iso-C17:1 ω9c (10.2\%) and C16:1 ω7c/C16:1 ω6c/iso-C15:0 2OH (summed feature 3) (14.4\%). The strains contained MK-7 as the major respiratory quinone, and phosphatidylethanolamine and five unidentified lipids as the polar lipids. Blast analysis of the 16S rRNA gene sequence of strain AK24(T) showed that it was closely related to Aquiflexum balticum, with a pair-wise sequence similarity of 91.6\%, as well as to Fontibacter ferrireducens, Belliella baltica and Indibacter alkaliphilus (91.3, 91.2 and 91.2\% pair-wise sequence similarity, respectively), but it only had between 88.6 and 91.0\% pair-wise sequence similarity to the rest of the family members. The MALDI-TOF assay reported no significant similarities for AK24(T) and AK26, since they potentially represented a new species. A MALDI MSP dendrogram showed close similarity between the two strains, but they maintained a distance from their phylogenetic neighbors. The genome of AK24(T) showed the presence of heavy metal tolerance genes, including the genes providing resistance to arsenic, cadmium, cobalt and zinc. A cluster of heat shock resistance genes was also found in the genome. Two lantibiotic producing genes, LanR and LasB, were also found in the genome of AK24(T). Strains AK24(T) and AK26 were very closely related to each other with 99.5\% pair-wise sequence similarity. Phylogenetic analysis indicated that the strains were members of the family Cyclobacteriaceae and they clustered with the genus Mariniradius, as well as with the genera Aquiflexum, Cecembia, Fontibacter, Indibacter, and Shivajiella. DNA-DNA hybridization between strains AK24(T) and AK26 showed a relatedness of 82\% and their rep-PCR banding patterns were very similar. Based on data from the current polyphasic study, it is proposed that the isolates be placed in a new genus and species with the name Lunatimonas lonarensis gen. nov., sp. nov. The type strain of Lunatimonas lonarensis is AK24(T) (=JCM 18822(T)=MTCC 11627(T)).

}, keywords = {Bacterial Typing Techniques, Bacteroidetes, Cluster Analysis, DNA, Bacterial, DNA, Ribosomal, Fatty Acids, Fresh Water, Genome, Bacterial, Geologic Sediments, India, Molecular Sequence Data, Nitrates, Oxidation-Reduction, Phospholipids, Phylogeny, Quinones, RNA, Ribosomal, 16S, Sequence Analysis, DNA}, issn = {1618-0984}, doi = {10.1016/j.syapm.2013.10.003}, author = {Srinivas, T N R and Aditya, S and Bhumika, V and Kumar, P Anil} } @article {1010, title = {Light driven ultrafast electron transfer in oxidative redding of Green Fluorescent Proteins. [Protein Technology Facility]}, journal = {Sci Rep}, volume = {3}, year = {2013}, month = {2013}, pages = {1580}, abstract = {

Fluorescent proteins undergoing green to red (G/R) photoconversion have proved to be potential tools for investigating dynamic processes in living cells and for photo-localization nanoscopy. However, the photochemical reaction during light induced G/R photoconversion of fluorescent proteins remains unclear. Here we report the direct observation of ultrafast time-resolved electron transfer (ET) during the photoexcitation of the fluorescent proteins EGFP and mEos2 in presence of electron acceptor, p-benzoquinone (BQ). Our results show that in the excited state, the neutral EGFP chromophore accepts electrons from an anionic electron donor, Glu222, and G/R photoconversion is facilitated by ET to nearby electron acceptors. By contrast, mEos2 fails to produce the red emitting state in the presence of BQ; ET depletes the excited state configuration en route to the red-emitting fluorophore. These results show that ultrafast ET plays a pivotal role in multiple photoconversion mechanisms and provide a method to modulate the G/R photoconversion process.

}, keywords = {Benzoquinones, Electron Transport, Green Fluorescent Proteins, Light, Oxidation-Reduction}, issn = {2045-2322}, doi = {10.1038/srep01580}, author = {Saha, Ranajay and Verma, Pramod Kumar and Rakshit, Surajit and Saha, Suvrajit and Mayor, Satyajit and Pal, Samir Kumar} } @article {537, title = {Redox proteomics of thiol proteins in mouse heart during ischemia/reperfusion using ICAT reagents and mass spectrometry.}, journal = {Free Radic Biol Med}, volume = {58}, year = {2013}, month = {2013 May}, pages = {109-17}, abstract = {

There is strong evidence for the involvement of reactive oxygen species in ischemia/reperfusion injury. Although oxidation of individual thiol proteins has been reported, more extensive redox proteomics of hearts subjected to ischemia/reperfusion has not been performed. We have carried out an exploratory study using mass spectrometry with isotope-coded affinity tags (ICAT) aimed at identifying reversible oxidative changes to protein thiols in Langendorff perfused isolated mouse hearts subjected to 20 min ischemia with or without aerobic reperfusion for 5 or 30 min. Reduced thiols were blocked by adding N-ethylmaleimide during protein extraction, then reversibly oxidized thiols in extracts of control perfused and treated hearts were reduced and labeled with the light and heavy ICAT reagents, respectively. Protein extracts were mixed in equal amounts and relative proportions of the isotope-labeled peaks were used to quantify oxidative changes between the control and the treated groups. Approximately 300 peptides with ICAT signatures were reliably identified in each sample, with 181 peptides from 118 proteins common to all treatments. A proportion showed elevated ICAT ratios, consistent with reversible thiol oxidation. This was most evident after early reperfusion, with apparent reversal after longer reperfusion. In comparison, there was gradual accumulation of protein carbonyls and loss of GSH with longer reperfusion. Many of the thiol changes were in mitochondrial proteins, including components of electron transport complexes and enzymes involved in lipid metabolism. The results are consistent with mitochondria being a major site of oxidant generation during early cardiac reperfusion and mitochondrial thiol proteins being targets for oxidation.

}, keywords = {Animals, Isotope Labeling, Mass Spectrometry, Mice, Mitochondrial Proteins, Myocardium, Oxidation-Reduction, Proteomics, Reactive Oxygen Species, Reperfusion Injury, Sulfhydryl Compounds}, issn = {1873-4596}, doi = {10.1016/j.freeradbiomed.2013.01.021}, author = {Kumar, Vikas and Kleffmann, Torsten and Hampton, Mark B and Cannell, Mark B and Winterbourn, Christine C} }