Department of Biotechnology

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Open Access
Exploring gut microbiome of a unique intestinal air-breathing fish Lepidocephalichthys guntea
(University of North Bengal, 2024) Basak, Chandana; Chakraborty, Ranadhir
The gastrointestinal (GI) tract is a favourable ecological niche for a large number of microorganisms, and as in other animal groups, a wide range of microbes colonizes the GI tract of fish. Although GI tract of fish is generally dominated by members of Bacillota, Pseudomonadota and Bacteroidota, bacterial abundance and pattern of dominance, strongly depends upon various biotic and abiotic factors that includes variety of fish, structure and microarchitecture of GI tract, condition of water, temperature, geographical regions, availability of nutrients and oxygen in water. The loach Lepidocephalichthys guntea is a freshwater fish of the family Cobitidae. Native to South and Southeast Asia, these loach exhibit market values as well as unique characteristics of intestinal breathing that make it an interesting addition to freshwater aquaculture as well as aquariums. They are bottom-dweller, often seen scavenging for small invertebrates and organic matter in the substrate. During eutrophication or drought these fish come to air water interface and gulp water through mouth that passes to intestine. After consumption of oxygen via posterior intestine, rest air is voided through the rectum. The first objective of our study was focused on isolation of both aerobic and facultatively anaerobic cultivable intestinal bacteria of L. guntea using conventional culture-based techniques. This study was aimed to investigate both the autochthonous and allocthonous gut bacterial population. For this, a set of wild healthy fish were dissected and intestinal bacteria were retrieved using the dilution plate technique on selective media. Gut bacteria of this fish showed considerable species diversity. These isolates were characterized using morphological and biochemical parameters that was further followed by taxonomic identification and construction of evolutionary lineage of each gut isolates. Results showed that Staphylococcus spp., Rhodococcus sp., Bacillus sp., Solibacillus sp., Verticiella sp., and Oceanobacillus sp. were allocthonous gut isolates while Enterobacter sp., Comamonas sp., Klebsiella sp., Shigella sp., and Staphylococcus spp. reflected the autochthonous gut bacterial population. In our second objective, these isolates were tested for several environmental stress factors that include temperature, salinity, pH, antibiotic resistance, and heavy metal resistance properties which yield a selection of six different isolates. Selected isolates named as Shigella sp. GCP5, Comamonas sp. GCA5, Staphylococcus sp. GCP4, Rhodococcus sp. GG48, Bacillus sp. GG161, and Verticiella sp. GG226 were subjected to whole genome sequencing and genome mining. Experiments showed that all six gut isolates showed growth when they were subjected to cold and heat stress in laboratory with lowest temperature tolerance of 4 oC and highest temperature tolerance of 42 oC. Genome mining revealed that all the isolates carry different sets of cold shock and heat shock response genes which enable them to tolerance the stress. While saline stress was applied on these isolates using NaCl, each of them showed different tolerance range. Genome mining showed that, salinity tolerance was performed majorly by potassium (K+) uptake. Also presence of genes encoding different compatible solutes like glycine betaine, ectoine, and proline were reflected all the gut isolates. Another stress factor was pH, against which these gut isolates showed a wide range of tolerance. The broadest range of pH tolerance was observed in Shigella sp. GCP5 that could tolerate a pH range of 3-13. On the contrary, Rhodococcus sp. GG48 showed smallest range of pH tolerance from 7-10. Genome mining of GCP5 showed that tolerance of acidic environment was due to presence of a periplasmic protein HDEA in its genome that supports acid resistance in pathogenic enteric bacteria. In the context of high pH, alkali tolerant isolates are expected to manage their metabolism through various strategies, including the proton transport system, enzymes such as proteases, lipases, cellulases, H+ coupled ion-transport systems, F0F1 ATPases, and transport systems that coordinate H+ transport with other solutes. Genes encoding distinct subunits of Na+/H+ antiporters and F0F1 ATPases were disclosed in the genome of all six isolates. Antibiotic resistance profiling of all six gut isolates showed that only Shigella sp. GCP5 has a broad spectrum of antibiotic resistance that includes monobactam, penicillin and beta lactam combination agents, ceftriaxone, erythromycin, imipenem and meropenem. A heavy metal resistance profiling was done for these isolates which showed a broad range of resistance that was distinct for all isolates. Genome mining of the gut isolates showed presence of different sets of heavy metal transportation systems. Third objective was focused on response of gut bacteria of gill-intesinal breather L. guntea during the hypoxic stress and comparison of this response with the changes of gut microbiota of a sole gill-breather fish Cirrhinus mrigala. Hypoxia is one of the main risks to fish health in an aquatic environment. High-throughput sequencing was used to examine the anterior and posterior guts of L. guntea in both normoxic and hypoxic conditions. According to the community profiling, prolonged exposure to hypoxia increased the diversity and abundance of bacteria in the posterior gut while decreasing both in the anterior gut. Additionally, the anterior and posterior gut's core microbiota showed a significant alteration during hypoxia. Comparative analyses showed that, hypoxia causes more pronounced alterations in the posterior gut bacteria than the anterior gut at various taxonomic levels. As a consequence of hypoxia, several pathogen populations were replaced by potential opportunistic pathogens. A surge in probiotic genera was also seen along with the shift in the pathogenic bacterial population. Similarly, comparison of gut microbiota of Cirrhinus mrigala was performed. As dissolved oxygen levels (DO2) decreased from 7±0.5 mg/L to 0.5±0.07 mg/L, a substantial shift was observed in the abundance and diversity of the bacterial population inhabiting the fish gut. The alpha diversity indices showed that the abundance and diversity of gut microflora increased in hypoxia as compared to normoxia. The community profiling indicates in case of hypoxia for both gut regions the number of core microbiota decreases as compared to normoxia. In hypoxic condition, the abundance of Pseudomonadota decreased in both guts while abundance of Firmicutes increased in the anterior gut but decreased in the posterior gut. With this, a rapid rise in probiotic bacteria Cetobacterium under hypoxia was observed. With this comparison of gut microbiota of Lepidocephalichthys guntea with Cirrhinus mrigala to reveal differences in the gut bacterial community during oxygen stressed environmental condition by meta-taxonomic study. The findings have illuminated a significant disparity in the composition of the gut microbiota between these twospecies. L. guntea exhibited a notably elevated microbial population within its gastrointestinal tract, accompanied by heightened levels of microbial diversity and richness as compared to C. mrigala. The fourth objective was concerned with the immune response provided by the gut immune system of L. guntea, when challenged with a pathogenic bacterium. L. guntea was experimentally infected with Aeromonas hydrophila using intraperitoneal injection followed by bath challenge, and transcriptome data were used to examine the gut immune responses during disease progression and recovery from the diseased state. For the control or uninfected fish (FGC) and the infected fish that were kept for seven days (FGE1) and fifteen days (FGE2), separate water tanks were set up. Coding DNA sequences (CDS) for FGC and FGE1, FGC and FGE2, and FGE1 and FGE2 were analyzed for differential gene expression (DGE). The presence and expression of genes involved in T cell receptor (TCR) signalling pathway, natural killer (NK) cell-mediated cytotoxicity pathway, and complement-mediated pathway, along with a large number of other immune-related proteins, and heat shock protein (HSPs) under various experimental conditions and its relationship to immune modulation of the fish gut was the primary focus of this study. Significant up-and-down regulation of these pathways shows that, in FGE1, the fish's innate immune system was engaged, whereas in FGE2, the majority of innate immune mechanisms were repressed, and adaptive immunity was activated. Expression of genes related to the immune system and heat-shock proteins was induced during this host's immunological response, and this information was then used to build a thorough network relating to immunity and the heat-shock response. This is the first study to examine the relationship between pathogenic bacterial infection, disease reversal, and modification of innate and adaptive immunity as well as heat shock response.
Open Access
Studies on siderophore producing and arsenic resistant bacteria isolated from agricultural soil and their role in biocontrol and bioremediation
(University of North Bengal, 2024) Pradhan, Smriti; Saha, Dipanwita
Arsenic is a toxic metalloid which cause serious health effects to human populationworldwide. Considered as a Group I carcinogen, it exists naturally in soil and ground water,however, human activities lead to high amount of arsenic pollution in these environments.Arsenic finds its entry into human food chain through different agricultural crops grown inarsenic polluted agricultural fields or fields where arsenic contaminated ground water is used for irrigation. In India, West Bengal tops the list of most contaminated states with several reports of arsenic toxicity in human. Therefore, there is an immense necessity for the implementation of efficient arsenic remediation strategies without harming the natural environment as done by the conventional methods for arsenic removal. In this consideration, arsenic remediation using microorganisms can be a cost effective and safer approach. Additionally, since several years, microorganisms have been used for controlling the agricultural crop loss caused due to the attack by plant pathogens. Rhizosphere microorganisms as biocontrol agents are being extremely used as an alternative to the use of synthetic chemicals for the better management of crop production. Moreover, nowadays, rhizobacteria are also receiving much attention in terms of their application in bioremediation of toxic compounds from soil. Therefore, through this study we aimed to focus on the rhizosphere inhabiting bacteria which can be applied as a potent multifunctional agent for arsenic bioremediation as well as in the biocontrol of plant pathogens. The work was conducted with a primary aim of isolating some highly arsenic resistant siderophoregenic strains with strong antagonism against plant pathogens. We then focused on the arsenic removal efficiency of potent isolates considering their field trials for arsenic bioremediation. Another aspect of this study was to prepare a stable and effective bioformulation for management of plant disease. We also isolated and characterized siderophore, suggesting its role as an antifungal metabolite as well as arsenic chelator. Overall, the work was conducted with the following objectives: (i) Isolation of siderophoregenic bacterial strains from agricultural soils and their screening for antifungal activity and arsenic resistance; (ii) Identification and phylogenetic analysis of the selective isolates based on 16S rRNA gene sequence; (iii) Evaluation of antagonistic potential of selected bacterial strains against plant pathogenic fungi; (iv) Characterisation of siderophore and metal complexation studies between siderophore and arsenic; (v) Analysing the presence of genetic determinants of arsenic resistance and antifungal property in the bacterial isolates; (vi) Batch study for arsenic removal from the soil by potent isolate; (vii) Studying the biocontrol potential of selected bacterial strain under greenhouse conditions. For bacterial isolation, rhizosphere soils were collected from agricultural fields of different regions of Darjeeling, Jalpaiguri, Cooch Behar, Alipurduar, Malda and Purulia districts of West Bengal. A total of 821 isolates were obtained from which 603 isolates were screened as siderophore producers. 500 siderophorogenic isolates with prominent haloes were tested for their resistance towards both forms of arsenic i.e., arsenate (AsV) and arsenite (AsIII) from which 230 isolates were able to grow in presence of both AsV and AsIII. Further, in vitro antifungal activity of these isolates was tested by dual culture method against six plant pathogens viz. Lasiodiplodia theobromae, Colletotrichum gloeosporioides, Curvularia eragrostidis, Fusarium oxysporum, Fusarium solani and Rhizoctonia solani. Here, thirty isolates were found to show strong antagonism against all test pathogens among which, three isolates BM3, CDG7 and GST18 were the most efficient antagonists. All thirty isolates were tested for the production of antifungal metabolites including extracellular lytic enzymes and HCN followed by detection of PGPR traits such as phosphatase and IAA production. Maximum isolates showed amylase production followed by lipase and amylase whereas a smaller number of isolates produced chitinase, cellulase and pectinase. Only two isolates showed HCN production. Four isolates were detected with both phosphatase and IAA production where highest amount of IAA was produced by BM3. Biofilm formation, which is also an important mechanism of biocontrol agents, was observed in two different media i.e., Luria Bertani (LB) and M9 yeast extract (M9YE) by all thirty isolates. Comparatively, maximum biofilm production occurred in LB medium where seven isolates appeared as strong biofilm formers. The identity of thirty potential isolates was revealed through morphological, biochemical and phylogenetic characterization. Through 16S rRNA gene sequencing and BLAST similarity search, isolates were distinguished into eight different genera where majority of the isolates (60%) belonged to genus Bacillus followed by Pseudomonas, Serratia, Microbacterium, Lysinibacillus, Proteus, Ensifer and Micrococcus. The sequences of all thirty isolates were deposited in NCBI GenBank and accession numbers were assigned as follows: MN133951, MN133999, MN865204, MN133963, MT032417, MN923204, MN148541, MN120803, MN865978, MN809373, MN809382, MN122130, MN809526, MN809529, MN108490, MN148539, MN809348, MN809357, MN809577, MN912102, MN120791, MN814034, MN865987, MN915155, MN814036, MN918097, MN809367, MN865968 and MN809363. The isolates were also subjected to hemolysis test considering the safety during field application where eighteen isolates were found to be non-hemolytic. Further, the level of arsenic resistance was checked by determining the minimum inhibitory concentration (MIC) of AsV and AsIII against thirty isolates in two different media i.e., LB and minimal salt (MS) medium. Highest MIC value of AsV was observed against M. luteus BPA2 irrespective of the growth medium. This strain also showed maximum resistance towards AsIII in MS medium while in case of LB medium, highest MIC value of AsIII was observed for B. amyloliquefaciens BM3. Arsenic transformation has been one of the mechanisms adopted by microorganisms to cope with arsenic toxicity. In this study, we tested arsenic reducing as well as arsenic oxidizing ability of all thirty isolates where nine isolates reported arsenate reduction and eight isolates showed arsenite oxidation in silver nitrate test. M. luteus BPA2 showed both the abilities of arsenic transformation. Detection for the genetic determinants of arsenate reduction (arsC gene for arsenate reductase) and arsenite oxidation (aoxB gene for arsenite oxidase) was also done inorder to correlate with the arsenic resistant phenotype of four highly resistant isolates. Successful PCR amplification of arsC gene was observed in all four isolates M. luteus BPA2, B. amyloliquefaciens BM3, P. putida BPA1 and L. macroides SUT34. However, aoxB gene was amplified in three isolates except L. macroides SUT34. The amplicons were cloned in pGEMT Easy vector and sequenced. The obtained gene sequences were submitted to GenBank through BankIt tool and the provided accession numbers are: arsC (OR875842, OL405606, OR195443 and OR228422) and aoxB (OR875841, OL405605 and OR875843). The growth study performed for M. luteus BPA2 and B. amyloliquefaciens BM3 (with highest MIC values) under arsenic stress in LB and MS media revealed higher impact of AsIII on the growth of both bacteria than AsV. Moreover, arsenic stress lowered the growth rate more in MS medium than LB medium. In comparison, M. luteus BPA2 showed better growth under arsenic stress in both media than B. amyloliquefaciens BM3. Scanning electron microscopy showed slightly irregular surface morphology of M. luteus BPA2 cells whereas an increase in cell size was observed in B. amyloliquefaciens BM3 under arsenic stress. M. luteus BPA2 and B. amyloliquefaciens BM3 showed efficient arsenic removal ability in both in vitro and in vivo studies. The quantitative study for siderophore production done through CAS shuttle assay revealed varied level of siderophore production by thirty isolates with B. amyloliquefaciens BM3 producing highest amount of siderophore (94.15 p.s.u). The chemical nature of siderophore was also detected where eighteen isolates produced hydroxamate type, thirteen isolates showed carboxylate type and only seven isolates were detected with catecholate type of siderophore. Siderophore from B. amyloliquefaciens BM3 was extracted and purified though Amberlite XAD2 and Sephadex LH20 column chromatography. Following purification, thin layer chromatography was done where a single spot was observed with Rf 0.84 under UV light (365 nm) and also by spraying with FeCl3. The compound was identified as bacillibactin through spectroscopic analyses including FT-IR, NMR and LCMS. Bacillibactin was studied for its metal chelating ability through qualitative and quantitative CAS assay which revealed that this siderophore could chelate both forms of arsenic apart from iron and the binding affinity was in the order Fe> AsV>AsIII. This observation was further confirmed by fluorescence spectroscopic analysis. SEM study of the interaction between our most potent biocontrol agent B. amyloliquefaciens BM3 and F. oxysporum shows several morphological abnormalities in the mycelia of fungal pathogen. The genes of three antifungal metabolites i.e, chitinase (chiA), bacilysin (bacAB) and surfactin (srfA) were successfully amplified through PCR in B. amyloliquefaciens and subsequently cloned and sequenced. The obtained gene sequences were submitted to GenBank and the following accession numbers were provided: chiA (OL335882), bacAB (MT740320) and srfA (OR228422). Soil inoculation of talc based formulation of B. amyloliquefaciens BM3 was considerably effective in controlling the Fusarium wilt disease in brinjal. The disease control efficiency of this strain was found to be more or less similar to that of the fungicide (thiophanate methyl). Moreover, this strain remained viable in talc formulation upto seven months at room temperature. In conclusion, the current study reports the recovery of useful strains from soil sample with multipurpose potential. The major findings of this study suggest the application of rhizospheric strains for cost effective removal of arsenic from soil. Moreover, we can also consider the development of formulation with the recovered strain as biocontrol products in eco-friendly agriculture. This study also witnesses the first report of arsenic chelation by bacillibactin thereby leading a new insight towards the application of this compound in combating arsenic toxicity in soils.
Open Access
Screening ayurveda based therapeutic preparations against multiple antibiotic-resistant gastro-enteric disease causing bacteria and to reveal the mode of action of the potential preparation(s)
(University of North Bengal, 2023) Chakraborty, Subhanil; Chakraborty, Ranadhir
Gastro-enteric diseases like diarrhea caused by the infection of multiple antibiotic-resistant bacteria result in to severe morbidity and mortality among young children and elderly population. The major problems occur due to rapid loss of fluids causing dehydration and eventual depletion of electrolytes essential for maintaining life functions. Within the short window of appearance of symptoms and choice of therapy, diagnosing the gastro-enteric diseases with proper etiology is very difficult because the disease manifested by the common symptoms like passing of watery stool, nausea, vomiting, weakness and sometimes fever may or may not be associated with bacterial infection. In most of the cases, single antibiotic therapy or simple treatment with common anti-diarrheal drugs fail to cease the occurrence of the disease and symptoms if the ailing person was infected by a multiple antibiotics-resistant gastro-enteric pathogenic bacteria. Evidently, the association of antibiotic resistance is increasing with time due to several clinical, habitual and environmental reasons. The scarcity of a proper therapeutic agent for addressing both the incidence of diarrhea and the probable chances of associated infection is alarming and requires action. Majority of the Ayurveda based medicines were supported by the observational findings of the practitioners over a myriad of diseases, disorders and symptoms for establishing the medicines therapeutic safety and efficacy. This current study was aimed at finding a suitable plant based natural therapeutic preparation which could counter both the problems of diarrhea and infections caused by multiple antibiotics resistant pathogenic bacteria localizing at stomach or intestines of a human being. The probable poly herbal therapeutic preparation would be evaluated for its safety and efficacy and an effort would be made to reveal the mode of action for further formulation development. After thorough literature survey, interviewing the Ayurveda practitioners and chemists and evaluating marketed products of different categories like oral liquid preparations comprising suspension or solutions, coarse dust products, encapsulated Ayurveda solid dosage forms and crude plant extracts, five different plant products were selected for preparation of a poly herbal hydro-ethanolic fermented formulation from among sixteen short listed plant materials based upon their potential to reduce diarrhea and also to exert anti-microbial actions. The poly herbal liquid preparation was prepared by following the basic instructions of Ayurvedic Pharmacopoeia of India and further evaluated for its safety on cytotoxicity study using human intestinal epithelial cell lines and rat intestinal cell lines. Oral toxicity studies were conducted to establish its safety prior to planning efficacy studies using rat model of diarrhea. The polyherbal preparation was found to be effectively arresting the symptoms of diarrhea by means of delaying the onset of symptoms and hastening the cessation of diarrhea as tested on castor oil induced animal disease model study and kaolin marked rate of gastric motility study also in rat model. The obtained results were compared statistically with medicines already in use for the treatment of diarrhea. The poly herbal Ayurveda based natural preparation was further found to be effective in dose dependent inhibition of growth or/and killing the population of several different genus and species of bacteria isolated from different origins. The developed formulation was found to exert a bactericidal action upon four different pathogenic hospital isolates belonging to genus Escherichia, Shigella and Salmonella, collected from Gastric Tract Pathogen Repository where each species of bacteria was known and retested in lab to exhibit multiple antibiotics resistance phenomena towards several different classes of antibiotics. Minimum inhibitory concentration and minimum bactericidal concentration of the poly herbal formulation were determined by following several antimicrobial assay methods for validation. All three common scientific antimicrobial assay techniques comprising broth dilution method, Agar diffusion method and microdilution method followed by serial dilution and plating were used to establish the formulation’s efficacy though in vitro assays against gastric pathogens and both Gram-positive and Gram-negative organisms. The formulation was evaluated thereafter on another animal model of burn wound infection and was found efficacious in topical usage to treat multiple antibiotics resistance also. One common mean of developing resistance among different species of bacteria was found to be through the formation of biofilms of exhibiting quorum sensing phenomena and showing swimming or swarming motility for spreading of infection. Three different assays were conducted using the polyherbal formulation and it depicted inhibition of quorum sensing phenomena and both swimming and swarming motility in all three assay techniques. The process of revealing the mode of action of a natural or unknown preparation was always the toughest hurdle in every drug discovery experiment. The primary chemical analysis of the poly herbal formulation revealed presence of mixtures of several different classes of organic compounds belonging to several different classes like flavonoids, alkaloids, glycosides, polyphenols and others. Some of these compounds could work synergistically to exhibit the efficacy already shown by the poly herbal formulation. However, qualitative chemical analysis wasn’t found sufficient for elucidation of the mode of action of the preparation. Hence, a relatively newer but effective method named Bacterial Cytological Profiling was adopted for the revelation of the mode of action against bacteria. It was already found that each species of bacteria produces different phenotypic features of both the cellular structure and nuclear material when treated with antibiotics working through different modes of action. Based on this basic observations, a couple of bacterial isolates were treated with ten different antibiotics to capture their fluorescence microscopy guided signature cytological profiles belonging to any particular pathway among the five major pathways or modes of actions through which antibiotics work. Both the bacteria were undergone by the treatment of the developed formulation under similar conditions as other antibiotics with known mode of action and the generated resulting bacterial cytological profile was matched through statistical principal components analysis and analysed cluster map revealed that the poly herbal formulation treated bacterial profiles matched very closely with the profiles generated by Kanamycin and Amikacin. Therefore, it was concluded that the poly herbal preparation developed with the support of the knowledge of Ayurveda was successfully exhibited anti-microbial action by inhibiting the bacterial protein synthesis. Scanning electron microscopy also revealed its action upon the outer membrane of Gram-positive and oligotrophic Gram-negative bacteria. This study examined and tried to establish the potential of an Ayurveda based poly herbal formulation in inhibiting multiple antibiotic resistant gastric pathogenic bacterial infections and also in reducing the severity of diarrhea. This study warranted the need of more detailed multicentric and multidisciplinary study to explore the full potential of the preparation and development of a proper dosage form for human use and benefit.
Open Access
Thermophilic lignocellulose deconstructing microbial consortium: Mining of Cellulolytic glycoside hydrolases for saccharification of agro residues
(University of North Bengal, 2023) Lepcha, Khusboo; Ghosh, Shilpi
Plant cell wall lignocellulose is recognized as one of the most abundant source of fennentable sugars with potential use in the production of different value added products like biofuel and other chemicals. Deconstruction of the complex lignocellulose into useable monomers by microbial enzymes has been long adapted; however a major bottleneck in efficient bioconversion of cellwall polysaccharide by enzymes is that plant cell walls have evolved to resist enzymatic deconstruction - a factor collectively known as "biomass recalcitrance". Using a broader suite of enzymes for hydrolysis of cellulose and hemicelluloses to fennentable sugars would be a better approach to combat biomass recalcitrance. Ln nature also, lignocellulosic biomass is degraded with the cooperation of many microorganisms producing a variety of cellulolytic and hemicellulolytic enzymes under aerobic and anaerobic conditions. The biodegradation of cellulosic biomass through the use of microbial co-cultures or complex communities has been proposed as a highly efficient approach for biotechnological application, since it avoids the problems of feedback regulation and metabolite repression posed by isolated single strains. In this study microbial communities of lignocellulosic habitat of forest soil (FS) and goat rumen contents (GR) were adapted to grow and survive at higher temperatures in destarched wheat bran /rice straw as sole carbon source to generate four thennophilic microbial consortia amongst which the consortium developed from goat rumen contents bred on rice straw (GR~ RS) was selected for further analysis due to its better hydrolytic potential on the basis of enzyme assays and in-gel analysis. Characterisation of cellulolytic and xylanolytic potential of GR-RS revealed both the cellulolytic and xylanolytic potential to be thennophilic and thermostable over a broad range of pH. The enzymes were tolerant to and activated in the presence of many metal ions such as Magnesium, Calcium, Barium, Sodium etc. whereas it was greatly reduced to 10% by Hg2+. Comparative Taxonomic profiling of GR-RS-T (developed at 60°C) and GR-RS-M (developed at 37°C) by meta.genomic analysis revealed GR-RS-M had a majority of Proteobacteria (48.67%), Finnicutes (30.34%), Verrucomicrobia (5.45%), Bacteroidetes (5. 12%), Planctomyecetes (3.13%), wheras GR-RS-T exhibited majority of bacteria belonging to phyla Proteobacteria (34.65%), Bacteroidetes (31 %) and Finnicutes (30.83%). Analysis of differential transcriptional expression of cellulolytic and xylanolytic enzymes in GR-RR-T revealed that expression of cellulases and xylanases were mostly from Paenibacillus , Thermobacillus, Pseudoclostridium, Geobacillus, Clostridium etc in case of GR-RS-T whereas its expression were mostly from Klebsiella, Cellulomonas and Pseudoxanthomonas in case of GR-RS-M. The analysis of transcriptome for distribution of different classes of CAZymes revealed that GR-RS-T had GH (34%), GT (38%), CBM (17%), AA (I%), CE (9%) and PL (1 %) whereas GR-RS-M had GH (29%), GT (43%), CBM (16%), AA (3%), CE (8%) and PL (I%). It was also revealed that most families of GH, PL and AA had higher abundance in GRRS- M as compared to GR-RS-T based on the number of reads detected. The study highlights the significance of sub-culturing the lignocellulolytic population from goat rumen contents at 60°C which selects and maintains the therrnophiJic members for production of thermophilic GHs as also evidenced by in vitro analysis. Comparison of saccharification potential of Conso,tiurn Enzyme Preparation (CEP) from GR-RS-T with commercial cellulase blend (CCB) on biologically pretreated rice straw (Spent rice straw) revealed a much higher release by CCB as compared to CEP indicating the supreme potential of the former which has been designed and developed for commercial applications. SEM image of SRS control showed prominent holes and cracks on its surface as compared to the intact strucrure of URS control indicating the delignification of rice straw and loosening of its structure during the growth of P!eurotus sp on rice straw. The structure of URS and SRS after saccharification showed prominently higher level of disorganisation when CCB was used as compared to CEP which cotTelated with the release of reducing sugars from the substrates. The release of reducing sugars in case of SRS-CEP ( 175 mg/gm) was comparable to, in fact slightly higher than URS-CCB (158 mg/gm) indicating that the saccharification potential of CEP could be made comparable to CCB if biologically pretreated rice straw was used. The outcome of this research contributes to the growing interest in lignocellulose deconstruction by enzymes, and highlights the potential of biological pretreatment in enhancing sacbharification by GHs.
Open Access
Studies on cellulase-producing bacteria isolated from a vermicompost-derived consortium and to evaluate their synergism in depolymerization of agricultural residues
(University of North Bengal, 2023) Basak, Arijita; Ghosh, Shilpi
The microorganisms growing in lignocellulose-degrading environment produce multiple enzyme systems that act synergistically to break down the polysaccharide constituents of JjgnocelluLosic material, namely cellulose, and bemicellulose. Vennicompost has taxonomically distinct microorganisms that could be used for the production of biocatalysts for the decomposition of industrial agroresidues. In this study, the microbial communities present in vermicompost were gradually adapted to grow at higher temperature of 60 °C while utilizing chopped rice straw as carbon source. The lignocellulolytic consortium RSV so developed exhibited the ability to degrade cellulose and hemicellulose. This was backed by quantitative estimation whereby RSV produced glycoside hydrolases belonging to cellulases such as exoglucanase, endoglucanase and ~-glucosidase with maximum activity of 5.8 ± 0.05, 19.56 ± 0.07 and 5.8 ± 0.03 ill/mg, respectively; and xylanases such as endoxylanase, ~xylosidase and a -L-arabinofuranosidase with highest activity 54 ± 15. 76, 5.2 ± 0.04, and 4.8 ± 0.03 IU/mg, respectively, on Day 2 of growth at pH 6 and 60 °C. The extracellular enzyme concentrate of RSV showed the ability to saccharify rice straw pretreated by glacial acetic acid, hydrogen peroxide, acid-peroxide combinations and heat The saccharification yield of reducing sugar equivalents was significantly greater from acid-peroxide combinations of 1: l (460 mg/g of rice straw), 2:1 (360 mg/g ofR and 4:1 (290 mg/g of rice straw on Day 5). The total genomic DNA of RSV was isolated, sequenced and the raw reads were trimmed and assembled into a metagenome for taxonomic and CAZyme profiling. The RSV consortium was comprised of a majority of bacteria from the phyla Finnicutes (56.91 %), Proteobacteria (28.32 %) and Bacteroidetes ( 12.22 %) and included members of the genera Pseudoc/osrridium (21.29 %), Chelatococcus ( I 6. l 3 %), Thermoanaerobacrerium (14.8 %), Algoriphagus (10.45 %), Bacillus (3.95 %), Pseudoxanthomonas (3.88 %), Geobacillus (3.57 %), Halomonas (3.29 %), Aeribacillus (3 .26 %) and Syrnbiobacterium (1.77 %) as the most abundant bacteria. Apart from producing GHs, RSV also produced enzymes belonging to CAZymes groups GH, CE and AA and auxiliary active enzymes such as multi copper oxidase, catalase/peroxidase, glycolate oxidase, GMC oxidoreductase and quinone oxidoreductase. Lignocellulolytic bacteria were obtained from RSV by dilution plating technique. Eight of them were capable of cellulose degradation while one was predominantly ligninolytic. Phylogenetic analysis of the isolates based on l 6S rRNA gene sequence identified these bacteria as belonging to genera Geobacillus, Parageobacillus, Aeribacil/us and Micrococcus. Among the bacterial isolates two cellulolytic isolates exhibiting significantly higher cellulase activity, Parageobacil!us thermoglucosidasius NBCB 1 (23.94±1 .34 TU/mg on Avicel, Day3), and Aeribacillus composti XLN l (22. 75± 1.50 ill/mg on A vicel, Day3 ), and the ligninolytic isolate Micrococcus yunnanensis B4 with laccase ()40.81±10.3 l μIU/mg on Day 3), lignin peroxidase (191. I 9±26.66 μTU/mg on Day 3) and manganese peroxidase (3239.73±177.11 μIU/mg oa Day 3) activities, were selected for the development of synthetic triculture consortium. The synthetic triculture consortium was further assessed for cellulase production and activity. Inoculation of the three cultures simultaneously to the celluJase production medium MSM-RS gave 53.24±0.96 TU/mg of cellulase production on Day 3 with the highest degree of synergy among all synthetic consortia (1.26±0.04). The cellulase production of the triculture was further optimized by OFAT (94.00±4.52 ill/mg), RSM-CCRD (115.68±0.01 ill/mg) and ANN-GA (139.00±0.00 IU/mg). Of all of them, ANN was found to give better process precision with optimized culture parameters of 3.33 days of incubation, medium pH of 6.06, 0.89 % sorbitol and 1.09 % peptone. The enzyme preparation obtained from triculture on the optimized MSM-RS medium was then utilized in the saccbarification of alkali, peroxy acetic acid, moist heat pretreated or untreated rice straw which gave reducing sugar equivalent yields of l 70.40±2.13 mglg of pretreated rice straw (Day 5), 156.00± l.25 mg/g (Day 5), 113.54±2.49 mg/g (Day 5) and 82.07±0.00 mg/g (Day 5), respectively, which were ~53.47, ~58.01 , ~65.87 and - 137.10 % of the yields from commercial cellulase Celluclast. The cellulase produced by Parageobacillus thermoglucosidasius NBCB 1 was purified to homogeneity, characterized and the encoding gene was cloned and sequenced. Before purifying, the enzyme production by the bacterium was enhanced to 78.47±2.23 IU/mg through ANN-GA. The cellulase enzyme, designated as PtCell , was purified through ammoniwn sulphate precipitation, gel filtration and DEAE-Sephacel anion exchange chromatography with 4 1.95-fold purification and final y ield 21 .52 %. The specific activity of PtCel 1 was 184 TU/mg on CMC and 305 IU/mg on A vicel thereby qualifying it as a processive endoglucanase. It was functional within a broad range of pH (4.5-8.5) and temperature (4-80 °C) with optimum activity at pH 5.5 and 60 °C. PtCel 1 showed enhanced activity in presence of Zn2+ (~369.14 %), Mg2+ (~245.15 %), Ca2 i (~261.10 %), Na+ (~ 179.77 %), Sn2+ (~ 150.80 %), SDS (- 132.8 %) and P-ME (~ 186.81 %). It was resistant to and retained activity in presence of galactose (~85.53 %), xylose (~74.28 %), cellobiose (~63.37 %), EDTA (- 62.18 %) and H202 (~33.33 %). PtCell had Km and Ymax at 0.363 mg/ml and 308.64 IU/mg, respectively. The putative gene encoding PtCell it was cloned and sequenced. It was characterized to be a Zn•dependeut endoglucanase/metallopeptidase from the M42 family.
Open Access
Biological Evaluation of Indigenous Medicinal Plants from Darjeeling Himalayan Region of West Bengal for Natural Compound(s) As Inhibitor of Cancer Cell Proliferation and Studies on their Molecular Mechanism
(University of North Bengal, 2023) Rai, Vijeta; Ghosh, Shilpi; Kumar, Anoop
Cancer remains one of the major world health issue after cardiovascular diseases. The area of cancer research is continually expanding with better understanding of molecular mechanism of progression of the disease, which has resulted in development of new drug targets for more efficient cancer therapy. In addition, the search for new anticancer lead compounds is a great challenge due to the development of drug resistance, deleterious side effects and unaffordable cost of current chemotherapeutic drugs. The enormous success of plant based natural products as anticancer agent represents medicinal plants as an important pool for the identification of novel drug. Darjeeling Himalayan region has a rich diversity of therapeutic plants that can be utilized for development of novel drugs. In this study some ethnomedicinally important plants of the Darjeeling Himalayan region, such as Astilbe rivularis, Tupistra nutans, Zanthoxylum oxyphyllum, Bergenia ciliata, Artemesia vulgaris and Eupatorium cannabium were screened for various phytochemicals, and antioxidant, antimicrobial activities, and cytotoxic potential against cancer cell lines, and finally, Astilbe rivularis was selected futher studies on isolation of active compound with anti-cancer potential. A steroid ester compound, spectrometrically characterized as Stigmasta-5(6), 22(23)-dien-3-beta–yl acetate, designated as A11, was isolated for the first time from the plant rhizome in a bioassay guided approach. The catalytic inhibition and structural alteration of human dihydrofolate reductase (hDHFR) by A11 was evaluated using methotrexate (MTX), a DHFR inhibitor anticancer drug as a reference. The compound was found to inhibit the in vitro activity of hDHFR) with IC50 values of 1.20 μM. A11 interacted with hDHFR as revealed by concentration dependent quenching of the tryptophan fluorescence of the enzyme suggesting its effect on structural alteration of the enzyme. Molecular docking of A11 on crystal structure of hDHFR revealed significant interaction with free energy of binding and Ki values of -10.86 kcal mol-1 and 11 nM, respectively. Subsequent in vitro studies at cellular level showed a relatively greater cytotoxic effect of A11 against human kidney (ACHN, IC50 60 μM) and liver (HepG2, IC50 70 μM) cancer cells than their respective normal cells (HEK-293, IC50 350 μM and WRL-68, IC50 520 μM). Scanning electron microscopy of A11 treated cells revealed the morphological feature of apoptosis, like cell rounding and surface detachment, membrane blebbing, loss of cilia and increased number of pores of decreased sizes. A11 mediated apoptosis of cancer cells was found to be correlated with induction of intracellular of reactive oxygen species (ROS) level and fragmentation of genomic DNA, which is a hallmark of apoptosis. A11 mediated induction of apoptotic feature of ACHN cells was found to be correlated with increased accumulation of cleaved active form of the pro-apoptotic proteins, like caspase 3, caspase 7, caspase 9 and PARP1. The cleaving of caspace 3 and caspase 7 was further confirmed by western blot analysis. The results thus provide an insight into the anti-tumorigenic potential of A11. The function of A11 in both inhibition of hDHFR and induction of apoptosis suggest that the compound could act via diverse signaling pathways of cancer cells without affecting normal cells. However, a possible link between hDHFR inhibition and cell cycle regulation needs to be illustrated in future studies. The outcomes of this research contribute to the growing field of natural product-based drug discovery and highlight the significance of traditional medicinal knowledge in the context of cancer treatment.
Open Access
Revealing molecular genetics of boron tolerance/resistance in bacteria using in-vivo evolutionary engineering and high throughput tools
(University of North Bengal, 2022) Sen, Subhajit; Chakraborty, Ranadhir
Boron (B), the fifth element is of pivotal biological importance in maintaining viable plant growth without causing mortal harm to biotic community of the surrounding soil. Over use of boron based compounds might result in causing boron toxicity and alteration of tolerance of boron by tolerant bacteria, capable of growing in presence of boron in atmosphere up to a certain level. In the present study, boron tolerant bacterial strains were isolated from soil samples with prolonged and chronic overexposure towards boron compounds in order to derive the fine line between boron toxicity and tolerance among relevant bacteria population and to estimate any possible diversities within the tolerant species. The fifth element, boron (B), is crucial for maintaining healthy plant growth without seriously harming the biotic community of the surrounding soil. When boron is used excessively (attaining concentrations which can cause boron toxicity), tolerant bacteria that grew in the presence of boron up to a certain level may change or enhance their B-tolerance. To determine the precise boundary between boron toxicity and tolerance among the relevant bacterial population and to gauge any potential diversities within the tolerant species, boron-tolerant bacterial strains were isolated from soil samples with prolonged and chronic overexposure to boron compounds. Identification of diversity in boron tolerant bacteria would be done for the first time in North Bengal area with an avenue in further studying the possible mechanisms of tolerance development and probable methods for transfer of the genotypic factors or environmental causes alleviating tolerance levels. From the 16S rRNA based phylogenetic and biochemical analysis it was found that all the boron-tolerant bacterial strains isolated boron contaminated agricultural fields belongs to three different genera, Lysinibacillus, Enterococcus and Bacillus. A couple of boron tolerant strains, Lysinibacillus sp. strain OL1 and Enterococcus sp. strain OL5, found to be tolerate 230 mM and 210 mM boron maximally in form of boric acid respectively, were ultimately selected for in-depth study. They, OL1 and OL5, were also tolerant to several other heavy metals and metalloids, such as, arsenic, cadmium, copper, mercury, zinc and nickel. In comparison to other metal pollutants, boric acid [B(OH)3] (approximately 96%) and a minor quantity of borate anion [B(OH)-4] are the two forms of boron that are the most mobile in soil. Both boric acid and borate can interact reversibly with different types of biomolecules like adenosine monophosphate, riboflavin, pyrimidine nucleotides, pyridoxine, ascorbic acid, and various sugar molecules (apiose, ribose, etc.) that contain an adjacent cis-hydroxyl group in their structure. Following growth kinetics and by Abstract measuring the amount of intracellular boron, it was primarily established that they were able to tolerate boron by using an inducible active efflux mechanism. This efflux mechanism enabled to maintain relatively less amount of boron in the intracellular milieu compared to the external B concentration. In order to validate the hypothesis, a potent efflux inhibitor PAβN was used; it was found that in the presence of PAβN (100 μg/ml) the level of B-tolerance got significantly reduced to 150 mM and 160 mM boron respectively, indicating that PAβN-sensitive-efflux pumps were partially responsible for B-tolerance. Three different omics tools, genomics, transcriptomis and proteomics, were used to generate data. Omics data were used to explore molecular mechanisms of boron tolerance in Lysinibacillus sp. OL1. RNA-free genomic DNA of OL1 was used for the construction of pair- end library for sequencing on NextSeq 500 system using Illumina platform. On the other hand, genomic DNA library of the strain OL5 was prepared using the Ion Xpress Plus fragment library kit (Thermo Fisher Scientific, USA) for Ion S5 next-generation sequencing platform (Thermo Fisher Scientific, USA). After annotation using NCBI Prokaryotic Genome Annotation Pipeline, it was found that the genome of OL1/OL5 isolates consisted of several number of efflux associated genes, 54/17 genes associated with MFS transporter, 263/283 genes associated with ABC transporter, 4/1 genes associated with SMR transporter, 2/1 genes associated with RND transporter and 4/2 genes associated with MATE transporter. Both the genomes were also containing a large number of genes associated with heavy metals and metalloids resistance. Total 33 and 30 heavy metals and metalloids resistance associated genes were present in the genome of OL1 and OL5 respectively. Beside all these, both OL1/OL5 genomes were found to contain at least 1/12 genes associated with phosphonate metabolism, 9/8 genes associated with auxin biosynthesis, 3/2 genes associated with siderophore or iron-siderophore transporter substrate binding, 8/2 genes associated with antioxidant activities, 78/40 genes associated with motility and chemotaxis, 6/39 genes associated with exo-polysaccharide production, and 7/ 23 genes associated with antimicrobial compounds and lytic enzymes production, which makes these two isolates a potential candidate for plant growth promoting rhizobacterial group. From the genomic and physiological analysis it was found that that OL1 have more genetic diversity and it can tolerate boron in more superior way compared to OL5. So, on the basis of these findings OL1 was selected for further studies. Total RNA and proteins were extracted from OL1 log phase growing culture according to standard methodology for transcriptomics and proteomics analysis. Following isolation, the proteome and transcriptome libraries were built and sequenced using the LC/MS and Illumina platforms, respectively. After the data had been Abstract sequenced and analysed, it was discovered that several stress response genes, efflux associated genes, energy metabolism, protein synthesis, and protein synthesis all played important roles in maintaining the integrity of the cell in the presence of an increased amount of extracellular boron. This result showed that multiple cellular metabolisms were involved in reducing the negative effects of boron on bacterial cells rather than just one. Furthermore, the most effective boron-tolerant isolate, OL1, has been subjected to in-vivo evolutionary engineering technique. It was discovered that OL-EC, an in-vivo evolutionary engineered cell, was able to tolerate 52.17% more boron than the OL1 wild type strain. The modified OL1-EC was able to withstand larger amounts of boron than the wild type of OL1, thus we tried to examine what mutations occurred in the OL1 genome and performed SNP-based mutational analysis. As a result of this analysis, we discovered that mutations occurred in a number of genes, including those encoding the ABC transporter ATP-binding protein, CPBP family intramembrane metalloprotease, transcription termination factor Rho, HEAT repeat domain-containing protein, GntR family transcriptional regulator, MarR family transcriptional regulator, oxidoreductase, FadR family transcriptional regulator, and a number of hypothetical proteins. We can infer from the results above that these advantageous mutations helped OL1-EC tolerate more boron. Future thorough studies utilising various omics methods, such as transcriptomics and proteomics, might give more details regarding the boron tolerance phenomenon in bacteria. OL1 and OL5 were both found to be positive for IAA production, phosphate solubilization, lytic enzyme production, motility, and biofilm production; this indicates that these boron tolerant isolates can promote plant growth in boron rich bare land and restore the soil quality. The plant growth promotion properties of these two isolates were also characterized. Finally, a metagenomic technique was used to study the microbial diversity of soil supplemented with boron. For metagenomic analysis, the total metagenomic DNAs from soil samples that had been modified with boron and those that hadn't were collected. Metagenomic libraries were then created. Ion torrent was then used to sequence the libraries. OTUs were created from the sequenced data, and comparative analysis was done. It was revealed from the metagenomic data that the gram positive phylum, Firmicutes is prevalent along with other bacterial genera. Interestingly, all of the recovered boron-tolerant strains belonged to Firmicutes. Therefore, it's probable to infer that high level of boron stress lead to a selection pressure that encourages the growth of Firmicutes-related Gram-positive bacteria. Additionally, it was noted that the phyla Acidobacteria, Actinobacteria, and Proteobacteria Abstract are abundant following Firmicutes. The entire study was designed to support the hypothesis that there are a variety of microbes in the soil of North Bengal that can tolerate boron levels above normal and that these microbes have an impact on the biological interactions between boron, bacteria, and soil systems, which have an impact on agriculture, the environment, and people's health.
Open Access
Studies on antioxidant, antimicrobial and antidiabetic activities of some ethnomedicinal plants collected from Darjeeling Himalayan region, West Bengal
(University of North Bengal, 2023) Das Vaskar; Ghosh Shilpi
Since the dawn of human civilization, plants and plant-derived natural remedies have been a vital part of traditional healing. With advances in development of synthetic drug, their usage has dominated over natural products. However, with several examples of synthetic drug side effects in recent decades, there has been a huge increase in the hunt for natural and safer pharmaceuticals. Plants derived phytochemicals or bioactive substances are safer and more cost-effective resource for drug development. The rate of development of numerous devastating oxidative stress-related disorders such as cancer, diabetes, atherosclerosis, arthritis, Alzheimer's disease, and other neurological disorders has grown as people's lifestyles have changed. Plant phytochemicals have been described as effective free radical scavengers or quenchers, making them a rich source of natural antioxidants. Herbal medications have been utilized for antibacterial, antiviral, antiinflammatory, anti-rheumatid, antiallergic and other purposes. The use of ethnomedicinal herbs in traditional medicine dates back over 2000 years; and many more beneficial therapeutic metabolites are expected to be discovered during later years. Despite being abundantly available and offering economic, ecological and therapeutic values, ethnic plants have received very little attention. The aim of this study was to screen and quantify different phytochemicals present in specific ethnomedicinal plants of Darjeeling district, West Bengal, Pin 734101, in light of the importance of natural products and their application as pharmaceuticals. The plant extracts were investigated for antioxidant, antimicrobial, and antidiabetic activities. Further, the cone extract of Thuja orientalis was fractionated by column chromatography for the isolation of active compound followed by characterization of the compound as Octacosanol. The antidiabetic potential of the compound was evaluated in streptozotocin (STZ) induced rat model. A systematic review of the literature has been assembled to provide the details of previous studies on the several bioactive substances found in plants and their antioxidant, antimicrobial and antidiabetic potential. For present investigation Thuja orientalis (THU), Tupistra nutans (TUP), Astilbe rivularis (AST), Calamus erectus (CAL), Zanthoxylum oxyphyllum (ZAN) and Artemisia vulgaris (ART) were collected from various locations of Darjeeling district. The plant materials were shed dried, powdered and extracted with various solvents. With the different solvents utilized, a difference in extraction yield was noticed. The yield percent was least with hot water and ethanol, while methanolic extracts produced the highest percentage of yield and therefore used for further studies. The plant methanolic extracts were examined qualitatively and quantitatively for the presence of phytochemicals. Among various secondary metabolites phenol, flavonoid, tannin, carbohydrate and reducing sugar were found to be present in all the extracts. The quantitative analysis showed THU cones having the highest quantity of phenol, flavonoid, tannin and total carbohydrate whereas ART leaf exhibited all these phytochemicals in least quantity. The plant extracts showed different degrees of antioxidant activities as measured by DPPH radical, H2O2, NO and ABTS scavenging assays. AST rhizome exhibited maximum antioxidant activity in assay based on DPPH, NO and ABTS assay, whereas THU cone showed highest activity with H2O2. The antibacterial potential of the plant extracts was tested against two gram positive (Bacillus amyloliquefaciens and Bacillus subtilis) and two gram negative (Flexibacter sp. and Aeromonas liquefaciens) bacteria. While comparing antibacterial effect of various plant extracts, the THU cone exhibited highest antibacterial activity against Bacillus amyloliquefaciens, Bacillus subtilis and Aeromonas liquefaciens whereas AST rhizome showed highest activity against Flexibacter sp. The plant extracts were effective in limiting the growth of tested fungi, namely, Aspergillus niger, Rhizopus stolonifer, and Fusarium oxysporum, as measured by radial growth bioassay. The extracts of THU cone and THU leaf effectively suppressed radial growth of all of the fungi examined, but TUP flower and CAL fruit extracts only partially inhibited the radial growth. Depending upon phytochemical constituents, antioxidant and antimicrobial activity, THU cone was found to exhibit the highest possible avenue for profiting from their use in pharmaceuticals. Hence THU cone was used for isolation and purification of bioactive molecule followed by its characterization by UV, IR and NMR spectroscopy and LC-ESI-MS analysis. The active compound in THU cone was characterized as Octacosanol with molecular formula C28H56O and molecular weight of 408. Octacosanol was found to inhibit the in vitro α-amylase activity, and its inhibitory effect was about two fold lesser than that of the positive control acarbose. In an in vivo antidiabetic assay on streptozotocin-induced diabetic rats, Octacosanol was found to be effective in restoring various blood parameters that had been altered by the induction of diabetes. Variable parameters evaluated was change in body weights, fasting blood sugar level, cholesterol, triglycerides and HDL cholesterol content, SGPT and SGOT activities and serum urea and creatinine level. Higher concentration of compound revealed higher reduction in the tested blood parameters than the lower concentration used in the study. Treatment with Octacosanol significantly improved and restored the histological structure of both liver and pancreas in STZ-induced diabetes rat. The molecule Octacosanol has potential application in pharmaceuticals due to its hypoglycemic, antimicrobial and antioxidant effects
Open Access
Antileishmanial and Antifungal activities of Ethno-Medicinally important plant extracts used by Tribal populations of North Bengal
(University of North Bengal, 2022) Chakraborty, Anindita; Saha, Dipanwita
Open Access
Search for molecular diversity of metallo-B-lactamase genes in eubacterial isolates of Karala and Mahananda rivers of West Bengal
(University of North Bengal, 2021) Ranjan, Vivek Kumar; Chakraborty, Ranadhir

Department of Biotechnology

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