Dr. Vinod Jyothikumar

In summary, this study contributes to our understanding of the complex morphogenetic program of streptomycetes, particularly regarding aerial hyphae formation and spore development. The researchers developed a time-lapse microscopy system to investigate the dynamic processes involved in streptomycete growth. Through genetic characterization, they identified the essential role of the SCO1389 gene in streptomycete growth and development, specifically related to membrane phospholipid biosynthesis.… Show more

In summary, this study contributes to our understanding of the complex morphogenetic program of streptomycetes, particularly regarding aerial hyphae formation and spore development. The researchers developed a time-lapse microscopy system to investigate the dynamic processes involved in streptomycete growth. Through genetic characterization, they identified the essential role of the SCO1389 gene in streptomycete growth and development, specifically related to membrane phospholipid biosynthesis. Localization studies using fluorescence microscopy and specific dyes provided valuable insights into the distribution of cardiolipin-rich domains in streptomycete cells. Show less

Effective disease surveillance and diagnostics are key for controlling infectious diseases globally. A pressing issue in biopharma is the potential environmental release of genetically modified microbes, which might have unpredictable effects. To mitigate biosafety risks, strategies are employed to limit microbial cell replication and horizontal gene transfer. The rapid growth in biosafety and biosecurity interest is due to the increased handling of pathogens and new biotech applications… Show more

Effective disease surveillance and diagnostics are key for controlling infectious diseases globally. A pressing issue in biopharma is the potential environmental release of genetically modified microbes, which might have unpredictable effects. To mitigate biosafety risks, strategies are employed to limit microbial cell replication and horizontal gene transfer. The rapid growth in biosafety and biosecurity interest is due to the increased handling of pathogens and new biotech applications. Biosafety ensures the safe use of infectious materials; biosecurity protects against unauthorized access or release. Risk assessment is crucial to establish the right containment level for biohazardous agents, recognizing that biological materials, unlike nuclear or chemical, can prompt widespread epidemics swiftly if not properly contained. Show less

Augmentation of CFTR maturation byS-nitrosoglutathione reductase.Am J Physiol Lung Cell Mol Physiol310: L263–L270, 2016. Firstpublished December 4, 2015; doi:10.1152/ajplung.00269.2014.—S-nitrosoglutathione (GSNO) reductase regulates novel endogenousS-nitrosothiol signaling pathways, and mice deficient in GSNO reduc-tase are protected from airways hyperreactivity.S-nitrosothiols arepresent in the airway, and patients with cystic fibrosis (CF) tend tohave lowS-nitrosothiol levels that may… Show more

Augmentation of CFTR maturation byS-nitrosoglutathione reductase.Am J Physiol Lung Cell Mol Physiol310: L263–L270, 2016. Firstpublished December 4, 2015; doi:10.1152/ajplung.00269.2014.—S-nitrosoglutathione (GSNO) reductase regulates novel endogenousS-nitrosothiol signaling pathways, and mice deficient in GSNO reduc-tase are protected from airways hyperreactivity.S-nitrosothiols arepresent in the airway, and patients with cystic fibrosis (CF) tend tohave lowS-nitrosothiol levels that may be attributed to upregulationof GSNO reductase activity. The present study demonstrates that1)GSNO reductase activity is increased in the cystic fibrosis bronchialepithelial (CFBE41o) cells expressing mutant F508del-cystic fibro-sis transmembrane regulator (CFTR) compared with the wild-typeCFBE41ocells,2) GSNO reductase expression level is increased inthe primary human bronchial epithelial cells expressing mutantF508del-CFTR compared with the wild-type cells,3) GSNO reduc-tase colocalizes with cochaperone Hsp70/Hsp90 organizing protein(Hop; Stip1) in human airway epithelial cells,4) GSNO reductaseknockdown with siRNA increases the expression and maturation ofCFTR and decreases Stip1 expression in human airway epithelialcells,5) increased levels of GSNO reductase cause a decrease inmaturation of CFTR, and6) a GSNO reductase inhibitor effectivelyreverses the effects of GSNO reductase on CFTR maturation. Thesestudies provide a novel approach to define the subcellular location ofthe interactions between Stip1 and GSNO reductase and the role ofS-nitrosothiols in these interactions. Show less

Exposure to hypoxia elicits an increase in minute ventilation that diminishes during continued exposure (roll-off). Brainstem N-methyl-D-aspartate receptors (NMDARs) and neuronal nitric oxide synthase (nNOS) contribute to the initial hypoxia-induced increases in minute ventilation. Roll-off is regulated by platelet-derived growth factor receptor-β (PDGFR-β) and S-nitrosoglutathione (GSNO) reductase (GSNOR). S-nitrosylation inhibits activities of NMDAR and nNOS, but enhances GSNOR activity. The… Show more

Exposure to hypoxia elicits an increase in minute ventilation that diminishes during continued exposure (roll-off). Brainstem N-methyl-D-aspartate receptors (NMDARs) and neuronal nitric oxide synthase (nNOS) contribute to the initial hypoxia-induced increases in minute ventilation. Roll-off is regulated by platelet-derived growth factor receptor-β (PDGFR-β) and S-nitrosoglutathione (GSNO) reductase (GSNOR). S-nitrosylation inhibits activities of NMDAR and nNOS, but enhances GSNOR activity. The importance of S-nitrosylation in the hypoxic ventilatory response is unknown. This study confirms that ventilatory roll-off is virtually absent in female GSNOR+/− and GSNO−/− mice, and evaluated the location of GSNOR in female mouse brainstem, and temporal changes in GSNOR activity, protein expression, and S-nitrosylation status of GSNOR, NMDAR (1, 2A, 2B), nNOS, and PDGFR-β during hypoxic challenge. GSNOR-positive neurons were present throughout the brainstem, including the nucleus tractus solitarius. Protein abundances for GSNOR, nNOS, all NMDAR subunits and PDGFR-β were not altered by hypoxia. GSNOR activity and S-nitrosylation status temporally increased with hypoxia. In addition, nNOS S-nitrosylation increased with 3 and 15 minutes of hypoxia. Changes in NMDAR S-nitrosylation were detected in NMDAR 2B at 15 minutes of hypoxia. No hypoxia-induced changes in PDGFR-β S-nitrosylation were detected. However, PDGFR-β phosphorylation increased in the brainstems of wild-type mice during hypoxic exposure (consistent with roll-off), whereas it did not rise in GSNOR+/− mice (consistent with lack of roll-off). These data suggest that: (1) S-nitrosylation events regulate hypoxic ventilatory response; (2) increases in S-nitrosylation of NMDAR 2B, nNOS, and GSNOR may contribute to ventilatory roll-off; and (3) GSNOR regulates PDGFR-β phosphorylation. Show less

The fluid mosaic model has recently been amended to account for the existence of membrane domains enriched in certain phospholipids. In rod-shaped bacteria, the anionic phospholipid cardiolipin is enriched at the cell poles but its role in the morphogenesis of the filamentous bacterium Streptomyces coelicolor is unknown. It was impossible to delete clsA (cardiolipin synthase; SCO1389) unless complemented by a second copy of clsA elsewhere in the chromosome. When placed under the control of an… Show more

The fluid mosaic model has recently been amended to account for the existence of membrane domains enriched in certain phospholipids. In rod-shaped bacteria, the anionic phospholipid cardiolipin is enriched at the cell poles but its role in the morphogenesis of the filamentous bacterium Streptomyces coelicolor is unknown. It was impossible to delete clsA (cardiolipin synthase; SCO1389) unless complemented by a second copy of clsA elsewhere in the chromosome. When placed under the control of an inducible promoter, clsA expression, phospholipid profile and morphogenesis became inducer dependent. TLC analysis of phospholipid showed altered profiles upon depletion of clsA expression. Analysis of cardiolipin by mass spectrometry showed two distinct cardiolipin envelopes that reflected differences in acyl chain length; the level of the larger cardiolipin envelope was reduced in concert with clsA expression. ClsA-EGFP did not localize to specific locations, but cardiolipin itself showed enrichment at hyphal tips, branch points and anucleate regions. Quantitative analysis of hyphal dimensions showed that the mycelial architecture and the erection of aerial hyphae were affected by the expression of clsA. Overexpression of clsA resulted in weakened hyphal tips, misshaped aerial hyphae and anucleate spores and demonstrates that cardiolipin synthesis is a requirement for morphogenesis in Streptomyces. Show less

Bacteria from the genus Streptomyces are among the most complex of all prokaryotes; not only do they grow as a complex mycelium, they also differentiate to form aerial hyphae before developing further to form spore chains. This developmental heterogeneity of streptomycete microcolonies makes studying the dynamic processes that contribute to growth and development a challenging procedure. As a result, in order to study the mechanisms that underpin streptomycete growth, we have developed a system… Show more

Bacteria from the genus Streptomyces are among the most complex of all prokaryotes; not only do they grow as a complex mycelium, they also differentiate to form aerial hyphae before developing further to form spore chains. This developmental heterogeneity of streptomycete microcolonies makes studying the dynamic processes that contribute to growth and development a challenging procedure. As a result, in order to study the mechanisms that underpin streptomycete growth, we have developed a system for studying hyphal extension, protein trafficking, and sporulation by time-lapse microscopy. Through the use of time-lapse microscopy we have demonstrated that Streptomyces coelicolor germ tubes undergo a temporary arrest in their growth when in close proximity to sibling extension sites. Following germination, in this system, hyphae extended at a rate of ∼20 μm h−1, which was not significantly different from the rate at which the apical ring of the cytokinetic protein FtsZ progressed along extending hyphae through a spiraling movement. Although we were able to generate movies for streptomycete sporulation, we were unable to do so for either the erection of aerial hyphae or the early stages of sporulation. Despite this, it was possible to demonstrate an arrest of aerial hyphal development that we suggest is through the depolymerization of FtsZ-enhanced green fluorescent protein (GFP). Consequently, the imaging system reported here provides a system that allows the dynamic movement of GFP-tagged proteins involved in growth and development of S. coelicolor to be tracked and their role in cytokinesis to be characterized during the streptomycete life cycle. Show less