Microbiologyhttp://irgu.unigoa.ac.in/drs/handle/unigoa/202026-09-03T03:07:42Z2026-09-03T03:07:42ZDeciphering salt tolerance mechanism in Brevibacterium sp. K11IcPPYGO002, from the coastal dunes of Keri, GoaVolvoikar, D.L.Garg, S.http://irgu.unigoa.ac.in/drs/handle/unigoa/79482026-08-21T06:52:50Z2026-01-01T00:00:00ZDeciphering salt tolerance mechanism in Brevibacterium sp. K11IcPPYGO002, from the coastal dunes of Keri, Goa
Volvoikar, D.L.; Garg, S.
The present study investigated the osmoadaptation strategies adopted by Brevibacterium sp. K11IcPPYGO002, a halotolerant novel strain isolated from the coastal dunes of Keri, Goa. Whole-genome sequencing revealed a genome size of 4,140,682 bp with a GC content of 63.97 percent. Genome annotation identified the ectoine/hydroxyectoine biosynthetic pathway, represented by the genes ask-asd, ectABC, and ectD, as well as the uptake system ehuABCD. The genes responsible for the biosynthesis of glutamate (gdhA), proline (proABC), and glycine betaine (betI and betABC) were detected. Trehalose and mannitol biosynthesis were indicated by the presence of genes otsAB and mtlK, respectively. Spermidine and putrescine synthesis were evidenced by speABC genes, along with the transport system (potABCD, potE, spuE). The genome harboured solute transporters (betT, betP, ectP, proP, opuA, opuC, gltT, proVWX), ion transporters, and osmoregulatory two-component systems (mtrA/B, kdpD/E), known to assist in salt tolerance. Functional validation of genomic data through LCMS confirmed the presence of intracellular compatible solutes (ICS) such as glutamic acid (146.20 [M-H]-, 147.90 [M+H]+), ectoine (142.90 [M+H]+), hydroxyectoine (158.90 [M+H]+), proline (116 [M+H]+), hydroxyproline (131.90 [M+H]+), choline (104 [M+H]+), glycine betaine (118 [M+H]+), dimethylsulfoniopropionate (135.90 [M]+), spermidine (145.90 [M+H]+), putrescine (111.90 [M+Na]), mannitol (182.90 [M+H]+) and trehalose (180.80 [C₆H₁₃O₆⁺]). LCMS-MRM demonstrated osmolarity-dependent increase in intracellular ectoine and hydroxyectoine, with ectoine peaking at 12 percent NaCl (25011.60 plus-minus 1852.69 ng/mg CDW) and hydroxyectoine at 16 percent NaCl (45.12 plus-minus 1.64 ng/mg CDW). STRING network analysis indicated coordinated ectoine biosynthesis. These findings provide genomic and metabolic insights into salt-stress adaptation in Brevibacterium sp. K11ICPPYGO002.
2026-01-01T00:00:00ZMetagenomic studies reveal diverse microbial community in the developmental stages of highly adaptable malarial vector Anopheles stephensi listonPereira, M.H.Tyagi, S.Mohanty, A.Garg, S.Ashwani Kumarhttp://irgu.unigoa.ac.in/drs/handle/unigoa/78182026-04-07T05:36:36Z2026-01-01T00:00:00ZMetagenomic studies reveal diverse microbial community in the developmental stages of highly adaptable malarial vector Anopheles stephensi liston
Pereira, M.H.; Tyagi, S.; Mohanty, A.; Garg, S.; Ashwani Kumar
Anopheles stephensi, a highly adaptable malaria vector species, continues to expand its range from South Asia to Sub-Saharan Africa, posing a serious global public health concern. In India, it serves as the principal urban vector of both Plasmodium falciparum and P. vivax. Conventional control measures reliant on chemical insecticides have raised issues of resistance, highlighting the need for alternative strategies such as microbiota-mediated vector control. This study aimed to test the hypothesis that a subset of bacterial taxa persist across developmental stages of An. stephensi, representing potential candidates for transstadial transmission and future paratransgenic manipulation. Using both culture-based data and next-generation sequencing (NGS) approaches targeting the 16 S rRNA gene (V3-V4 region), we characterized bacterial communities from breeding water, larvae, pupae, and adult mosquitoes (male and female) collected in Goa, India. Across all developmental stages, Proteobacteria and Firmicutes were the dominant phyla, while 15 bacterial genera formed the putative core microbiome shared by greater than or equal to 80 percent of stages at greater than or equal to 0.1 percent abundance. Among these, Pseudomonas (adult males: 11.5 percent, pupae: 3.2 percent), Exiguobacterium, Acinetobacter, Psychrobacter, and Asticcacaulis were consistently detected, together contributing approximately 30 percent of total microbial composition. Alpha diversity indices indicated higher richness and evenness in pupae and adults than in larvae, suggesting microbial enrichment during metamorphosis. Beta diversity and PCoA analyses clustered pupal and adult stages distinctly from larvae and breeding water, confirming selective microbial retention through development. These findings reveal that An. stephensi harbors a stable, stage-spanning core microbiome dominated by metabolically versatile genera with potential for transstadial persistence. The dominance of Pseudomonas across life stages supports its candidacy for paratransgenic applications aimed at disrupting malaria transmission. This work provides the first integrated culture-NGS baseline of An. stephensi microbiota from India, offering essential insight for microbiome-based vector control strategies.
2026-01-01T00:00:00ZEfficacy of nonantimicrobial drugs against Enterococcus faecalis using confocal laser scanning microscopy - An in vitro studyFerrao, T.M.Ataide, I.Lambor, R.Kashyap, S.Biswas, S.Salkar, K.S.Charya, L.S.http://irgu.unigoa.ac.in/drs/handle/unigoa/78012026-03-06T08:38:56Z2026-01-01T00:00:00ZEfficacy of nonantimicrobial drugs against Enterococcus faecalis using confocal laser scanning microscopy - An in vitro study
Ferrao, T.M.; Ataide, I.; Lambor, R.; Kashyap, S.; Biswas, S.; Salkar, K.S.; Charya, L.S.
Enterococcus faecalis is a key contributor to persistent endodontic infections and often shows resistance to conventional medicaments such as calcium hydroxide. Growing antimicrobial resistance has led to interest in repurposing nonantibiotic drugs such as nonsteroidal anti-inflammatory drugs and proton-pump inhibitors that have shown promising antimicrobial effects against E. faecalis. The study aimed to evaluate the in vitro antibiofilm activity of different combinations of nonantimicrobial drugs with and without calcium hydroxide against E. faecalis.
2026-01-01T00:00:00ZField evaluation of bacterial wilt resistant lines and identification of promising bacterial wilt resistant varieties for Coastal regionRamesh, R.D'Souza, M.Asolkar, T.Achari, G.Gaitonde, S.Thangam, M.http://irgu.unigoa.ac.in/drs/handle/unigoa/77962026-03-05T06:18:54Z2021-01-01T00:00:00ZField evaluation of bacterial wilt resistant lines and identification of promising bacterial wilt resistant varieties for Coastal region
Ramesh, R.; D'Souza, M.; Asolkar, T.; Achari, G.; Gaitonde, S.; Thangam, M.
Cultivation of brinjal in Coastal regions of India is severely affected by bacterial wilt disease caused by Ralstonia solanacearum. In this study, recombinant inbred lines were developed and screened for bacterial wilt resistance. Seventeen promising resistant lines were evaluated in the field for two years and the results indicated these lines were resistant to bacterial wilt. Lines 262-4, 5-12-1, 66-8-1, 205-1, 12-2-4 and 28-8-5 were promising among the purple types (0 to 4 percent wilt and yield 0.51 to 0.93 kg/ plant). Among the green types, lines 5-8-1, 93-8-1 and 92-3-7 were promising (0 to 5 percent wilt and yield 0.64 to 0.79 kg/ plant). Demonstration of eight lines in farmer's field indicated that lines 262-4, 5-12-1, 205-1, 5-8-1 and 12-2-4 were least infected (3 to 17 percent). Based on these studies, four purple lines 262-4, 5-12-1, 66-8-1 and 205-1 were released as bacterial wilt resistant brinjal varieties in the State of Goa.
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