144 results on '"Koley, H."'
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2. Immunization of Mice with a Live Transconjugant Shigella Hybrid Strain Induced Th1 and Th17 Cell-Mediated Immune Responses and Confirmed Passive Protection Against Heterologous Shigellae
- Author
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Nag, D., Koley, H., Sinha, R., Mukherjee, P., Sarkar, C., Withey, J. H., and Gachhui, R.
- Published
- 2016
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3. Inhibition of growth and virulence ofVibrio choleraeby carvacrol, an essential oil component ofOriganumspp.
- Author
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Das, S., primary, Chourashi, R., additional, Mukherjee, P., additional, Kundu, S., additional, Koley, H., additional, Dutta, M., additional, Mukhopadhyay, A.K., additional, Okamoto, K., additional, and Chatterjee, N.S., additional
- Published
- 2021
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4. Sequential Changes in Gut Mucosa of Rabbits Infected with Vibrio cholerae O139 Bengal: an Ultrastructural Study
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Saha, DR, Koley, H, Ghosh, AN, and Nair, GB
- Published
- 1997
5. Telomerase inhibitor GRN163L inhibits myeloma cell growth in vitro and in vivo
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Shammas, M A, Koley, H, Bertheau, R C, Neri, P, Fulciniti, M, Tassone, P, Blotta, S, Protopopov, A, Mitsiades, C, Batchu, R B, Anderson, K C, Chin, A, Gryaznov, S, and Munshi, N C
- Published
- 2008
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6. Inhibition of growth and virulence of Vibrio cholerae by carvacrol, an essential oil component of Origanum spp.
- Author
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Das, S., Chourashi, R., Mukherjee, P., Kundu, S., Koley, H., Dutta, M., Mukhopadhyay, A.K., Okamoto, K., and Chatterjee, N.S.
- Subjects
VIBRIO cholerae ,CARVACROL ,ESSENTIAL oils ,ANTIBIOTICS ,DRUG resistance in bacteria ,CHOLERA ,ORIGANUM - Abstract
Aims: In the age where bacterial resistance to conventional antibiotics is increasing at an alarming rate, the use of the traditional plant, herb extracts or other bioactive constituents is gradually becoming popular as an anti‐virulence agent to treat pathogenic diseases. Carvacrol, a major essential oil fraction of Oregano, possesses a wide range of bioactivities. Therefore, we aimed to study the effect of sub‐inhibitory concentrations of carvacrol on major virulence traits of Vibrio cholerae. Methods and Results: We have used in vitro as well as ex vivo models to access the anti‐pathogenic role of carvacrol. We found that the sub‐inhibitory concentration of carvacrol significantly repressed bacterial mucin penetrating ability. Carvacrol also reduced the adherence and fluid accumulation in the rabbit ileal loop model. Reduction in virulence is associated with the downregulated expression of tcpA, ctxB, hlyA and toxT. Furthermore, carvacrol inhibits flagellar synthesis by downregulating the expression of flrC and most of the class III genes. Conclusions: Carvacrol exhibited anti‐virulence activity against V. cholerae, which involved many events including the inhibition of mucin penetration, adhesion, reduced expression of virulence‐associated genes culminating in reduced fluid accumulation. Significance and Impact of the Study: These findings indicate that carvacrol possesses inhibitory activity against V. cholerae pathogenesis and might be considered as a potential bio‐active therapeutic alternative to combat cholera. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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7. Antibacterial activity of polyphenolic fraction of Kombucha against Vibrio cholerae : targeting cell membrane
- Author
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Bhattacharya, D., primary, Ghosh, D., additional, Bhattacharya, S., additional, Sarkar, S., additional, Karmakar, P., additional, Koley, H., additional, and Gachhui, R., additional
- Published
- 2018
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8. Antibacterial activity of polyphenolic fraction of Kombucha against <italic>Vibrio cholerae</italic>: targeting cell membrane.
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Bhattacharya, D., Ghosh, D., Bhattacharya, S., Sarkar, S., Karmakar, P., Koley, H., and Gachhui, R.
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POLYPHENOLS ,KOMBUCHA tea ,BACTERIAL growth prevention ,ANTIBACTERIAL agents ,CATECHIN ,THERAPEUTICS - Abstract
Abstract: The present study was undertaken to determine the mechanism of antibacterial activity of a polyphenolic fraction, composed of mainly catechin and isorhamnetin, previously isolated from Kombucha, a 14‐day fermented beverage of sugared black tea, against the enteropathogen
Vibrio cholerae N16961. Bacterial growth was found to be seriously impaired by the polyphenolic fraction in a dose‐dependent manner. Scanning Electron Microscopy demonstrated morphological alterations in bacterial cells when exposed to the polyphenolic fraction in a concentration‐dependent manner. Permeabilization assays confirmed that the fraction disrupted bacterial membrane integrity in both time‐ and dose‐dependent manners, which were proportional to the production of intracellular reactive oxygen species (ROS). Furthermore, each of the polyphenols catechin and isorhamnetin showed the ability to permeate bacterial cell membranes by generating oxidative stress, thereby suggesting their role in the antibacterial potential of Kombucha. Thus, the basic mechanism of antibacterial activity of the Kombucha polyphenolic fraction againstV. cholerae involved bacterial membrane permeabilization and morphological changes, which might be due to the generation of intracellular ROS. To the best of our knowledge, this is the first report on the investigation of antibacterial mechanism of Kombucha, which is mostly attributed to its polyphenolic content. Significance and Impact of the Study: The emergence of multidrug‐resistantVibrio cholerae strains has hindered an efficient anti‐Vibrio therapy. This study has demonstrated the membrane damage‐mediated antibacterial mechanism of Kombucha, a popular fermented beverage of sugared tea, which is mostly attributed to its polyphenolic content. This study also implies the exploitation of Kombucha as a potential new source of bioactive polyphenols againstV. cholerae . [ABSTRACT FROM AUTHOR]- Published
- 2018
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9. Isolation of NDM-1-producing multidrug-resistant Pseudomonas putida from a paediatric case of acute gastroenteritis, India
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Bhattacharya, D., primary, Dey, S., additional, Kadam, S., additional, Kalal, S., additional, Jali, S., additional, Koley, H., additional, Sinha, R., additional, Nag, D., additional, Kholkute, S.D., additional, and Roy, S., additional
- Published
- 2015
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10. Effective Elimination of Drug Resistance Genes in Pathogenic Pseudomonas aeruginosa by Antipsychotic Agent Thioridazine
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Mukherjee, S., primary, Chaki, S., additional, Barman, S., additional, Das, S., additional, Koley, H., additional, and Dastidar, S.G., additional
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- 2011
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11. Cholera Toxin Production by the El Tor Variant ofVibrio choleraeO1 Compared to Prototype El Tor and Classical Biotypes
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Ghosh-Banerjee, J., primary, Senoh, M., additional, Takahashi, T., additional, Hamabata, T., additional, Barman, S., additional, Koley, H., additional, Mukhopadhyay, A. K., additional, Ramamurthy, T., additional, Chatterjee, S., additional, Asakura, M., additional, Yamasaki, S., additional, Nair, G. B., additional, and Takeda, Y., additional
- Published
- 2010
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12. Enterotoxigenicity of Mature 45-Kilodalton and Processed 35-Kilodalton Forms of Hemagglutinin Protease Purified from a Cholera Toxin Gene-Negative Vibrio cholerae Non-O1, Non-O139 Strain
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Ghosh, A., primary, Saha, D. R., additional, Hoque, K. M., additional, Asakuna, M., additional, Yamasaki, S., additional, Koley, H., additional, Das, S. S., additional, Chakrabarti, M. K., additional, and Pal, A., additional
- Published
- 2006
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13. Novel and potent telomerase antagonist (GRN163L) inhibits telomerase activity, resulting in telomere shortening and apoptosis of multiple myeloma cells
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Shammas, M. A., primary, Koley, H., additional, Tassone, P., additional, Neri, P., additional, Protopopov, A., additional, Gryaznov, S., additional, Chin, A., additional, Anderson, K. C., additional, and Munshi, N. C., additional
- Published
- 2005
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14. Construction of a recombinant live oral vaccine from a non-toxigenic strain of Vibrio cholerae O1 serotype Inaba biotype El Tor and assessment of its reactogenicity and immunogenicity in the rabbit model
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Thungapathra, M., primary, Sharma, C., additional, Gupta, N., additional, Ghosh, R.K., additional, Mukhopadhyay, A., additional, Koley, H., additional, Balakrish Nair, G., additional, and Ghosh, Amit, additional
- Published
- 1999
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15. Double-blind, randomized clinical trial for safety and efficacy of norfloxacin for shigellosis in children
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Bhattacharya, SK, primary, Bhattacharya, MK, additional, Dutta, D, additional, Dutta, S, additional, Deb, M, additional, Deb, A, additional, Das, KP, additional, Koley, H, additional, and Nair, GB, additional
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- 1997
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16. Purification and characterization of an extracellular secretogenic non-membrane-damaging cytotoxin produced by clinical strains of Vibrio cholerae non-O1
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Saha, P K, primary, Koley, H, additional, and Nair, G B, additional
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- 1996
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17. Nontoxigenic Vibrio cholerae 01 serotype Inaba biotype El Tor associated with a cluster of cases of cholera in southern India
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Saha, P K, primary, Koley, H, additional, Mukhopadhyay, A K, additional, Bhattacharya, S K, additional, Nair, G B, additional, Ramakrishnan, B S, additional, Krishnan, S, additional, Takeda, T, additional, and Takeda, Y, additional
- Published
- 1996
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18. Cholera Toxin Production by the El Tor Variant of Vibrio choleraeO1 Compared to Prototype El Tor and Classical Biotypes
- Author
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Ghosh-Banerjee, J., Senoh, M., Takahashi, T., Hamabata, T., Barman, S., Koley, H., Mukhopadhyay, A. K., Ramamurthy, T., Chatterjee, S., Asakura, M., Yamasaki, S., Nair, G. B., and Takeda, Y.
- Abstract
ABSTRACTVibrio choleraeO1 El Tor variant strains produced much more cholera toxin than did prototype El Tor strains. The amount of cholera toxin produced by El Tor variant strains both in vitroand in vivowas more or less equivalent to that produced by classical strains.
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- 2010
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19. Enterotoxigenicity of Mature 45-Kilodalton and Processed 35-Kilodalton Forms of Hemagglutinin Protease Purified from a Cholera Toxin Gene-Negative Vibrio choleraeNon-O1, Non-O139 Strain
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Ghosh, A., Saha, D. R., Hoque, K. M., Asakuna, M., Yamasaki, S., Koley, H., Das, S. S., Chakrabarti, M. K., and Pal, A.
- Abstract
ABSTRACTCholera toxin gene-negative Vibrio choleraenon-O1, non-O139 strain PL-21 is the etiologic agent of cholera-like syndrome. Hemagglutinin protease (HAP) is one of the major secretory proteins of PL-21. The mature 45-kDa and processed 35-kDa forms of HAP were purified in the presence and absence of EDTA from culture supernatants of PL-21. Enterotoxigenicities of both forms of HAP were tested in rabbit ileal loop (RIL), Ussing chamber, and tissue culture assays. The 35-kDa HAP showed hemorrhagic fluid response in a dose-dependent manner in the RIL assay. Histopathological examination of 20 μg of purified protease-treated rabbit ileum showed the presence of erythrocytes and neutrophils in the upper part of the villous lamina propria. Treatment with 40 μg of protease resulted in gross damage of the villous epithelium with inflammation, hemorrhage, and necrosis. The 35-kDa form of HAP, when added to the lumenal surface of rat ileum loaded in an Ussing chamber, showed a decrease in the intestinal short-circuit current and a cell rounding effect on HeLa cells. The mature 45-kDa form of HAP showed an increase in intestinal short-circuit current in an Ussing chamber and a cell distending effect on HeLa cells. These results show that HAP may play a role in the pathogenesis of PL-21.
- Published
- 2006
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20. Apical KCNN4c channel regulated by Epac1 signaling affect epithelial Cl- secretion in diarrhea.
- Author
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Sheikh, I. A., Sinah, R., Nag, D., Koley, H., Chakraborty, M. K., and Kazi, M. H.
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POTASSIUM channels ,DIARRHEA ,INTESTINES - Abstract
KCNN4 (IK) is a calcium activated potassium (K) channel. However, its role in diarrhea and regulation by Epac1 in cAMP stimulation is unknown. By RT-PCR and Western blot, we dentified KCNN4 expression in mouse intestine and human intestinal cell line. We hypothesized that apical KCNN4 was involved in diarrhea and regulated by Epac1 associated signaling. Depletion of Epac1 protein and apical addition of TRAM-34, a specific KCNN4 inhibitor significantly abolished cAMP stimulated Cl secretion and apical K conductance IK(ap) in T84 cells. We studied the current-voltage relationships in basolaterally permeabilized monolayers treated with 8-pCPT-2'-O-Me-cAMP in a symmetric K ion concentration. The presence of an inwardly rectified, Ca-activated K channel was evident in T84WT cells, whereas 8-pCPT-2'-O-Me-cAMP was not able to activate this inwardly rectified current in Epac1 knock down (Epac1KDT84) cells. Furthermore, addition of KCNN4 channel specific activator, 1-EBIO to intact wild type (T84WT) cells resulted 44±5 µA/cm2 rise in Isc while in Epac1KDT84 cells and T84WT + TRAM 34, 1-EBIO enhanced Isc was only 5±1 µA/cm2 and 4 ± 3 µA/cm2 respectively. Reconstructed confocal image in the X-Z plane of T84Epac1KD monolayers revealed redistribution of KCNN4c proteins into sub-apical intracellular compartment. We compared the surface amount of KCNN4c in these cells that Epac1 depleted cells have
~ 83% lower surface membrane expression of KCNN4c compared with T84WT cells. The role of Epac1-Rap1 signaling in endogenous regulation of KCNN4 was further assessed in T84 cells by Rap1 activation assays. FSK and 8-pCPT-2'-O-Me-cAMP induced GTP-loading of Rap1 in T84WT cells. To better understand the specific involvement of Rho-A and Rho-associated kinase ROCK in KCNN4 regulation in intestinal Cl secretion, Isc and IK(ap) was measured in T84WT cells. Finding that both Rho-A and ROCK kinase inhibitors significantly reduced FSK stimulated Isc as well as IK(ap). To explore the therapeutic potential of Epac1 regulated signaling of KCNN4c channels, we tested the effect of Rap1a inhibitor GGTI-298, ROCK inhibitor H1152 or KCNN4c inhibitor TRAM-34, in a closed loop mouse model. Our result demonstrated Epac1-Rap1-Rho-A-ROCK signaling lead to the alleviation of diarrhea by recruiting KCNN4c to the apical membrane which has important therapeutic value in diarrhea [ABSTRACT FROM AUTHOR]- Published
- 2013
21. Rotavirus non-structural protein 4 usurps host cellular RIPK1-RIPK3 complex to induce MLKL-dependent necroptotic cell death.
- Author
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Chandra P, Patra U, Mukhopadhyay U, Mukherjee A, Halder P, Koley H, and Chawla-Sarkar M
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- Humans, Animals, Host-Pathogen Interactions, Toxins, Biological metabolism, Receptor-Interacting Protein Serine-Threonine Kinases metabolism, Receptor-Interacting Protein Serine-Threonine Kinases genetics, Viral Nonstructural Proteins metabolism, Viral Nonstructural Proteins genetics, Protein Kinases metabolism, Protein Kinases genetics, Necroptosis, Rotavirus metabolism
- Abstract
The dynamic interface between invading viral pathogens and programmed cell death (PCD) of the host is a finely regulated process. Host cellular demise at the end of the viral life cycle ensures the release of progeny virions to initiate new infection cycles. Rotavirus (RV), a diarrheagenic virus with double-stranded RNA genome, has been reported to trigger different types of PCD such as apoptosis and pyroptosis in a highly regulated way to successfully disseminate progeny virions. Recently our lab also showed that induction of MLKL-driven programmed necroptosis by RV. However, the host cellular machinery involved in RV-induced necroptosis and the upstream viral trigger responsible for it remained unaddressed. In the present study, the signalling upstream of MLKL-driven necroptosis has been delineated where the involvement of Receptor interacting serine/threonine kinase 3 (RIPK3) and 1 (RIPK1) from the host side and RV non-structural protein 4 (NSP4) as the viral trigger for necroptosis has been shown. Interestingly, RV-NSP4 was found to be an integral component of the necrosome complex by interacting with RIPK1, thereby bypassing the requirement of RIPK1 kinase activity. Subsequently, NSP4-driven elevated cytosolic Ca
2+ concentration and Ca2+ -binding to NSP4 lead further to RHIM domain-dependent RIPK1-RIPK3 interaction, RIPK3-dependent MLKL phosphorylation, and eventual necroptosis. Overall, this study presents the interplay between RV-NSP4 and the host cellular necrosome complex to induce necroptotic death of host cells., Competing Interests: Declaration of competing interest Authors have no conflicts of interest in relation to this work., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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22. Establishment of an intragastric surgical model using C57BL/6 mice to study the vaccine efficacy of OMV-based immunogens against Helicobacter pylori.
- Author
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Das S, Halder P, Banerjee S, Mukhopadhyay AK, Dutta S, and Koley H
- Abstract
Chronic gastritis is one of the major symptoms of gastro-duodenal disorders typically induced by Helicobacter pylori (H. pylori). To date, no suitable model is available to study pathophysiology and therapeutic measures accurately. Here, we have presented a successful surgical infection model of H. pylori-induced gastritis in C57BL/6 mice that resembles features similar to human infection. The proposed model does not require any preparatory treatment other than surgical intervention. C57BL/6 mice were injected with wild-type SS1 (Sydney strain 1, reference strain) directly into the stomach. Seven days post infection, infected animals showed alterations in cytokine responses along with inflammatory cell infiltration in the lamina propria, depicting a prominent inflammatory response due to infection. To understand the immunogenicity and protective efficacy, the mice were immunized with outer membrane vesicles (OMVs) isolated from an indigenous strain with putative virulence factors of H. pylori [A61C (1), cag+/vacA s1m1]. In contrast to the non-immunized cohort, the OMV-immunized cohort showed a gradual increase in serum immunoglobulin(s) levels on the 35th day after the first immunization. This conferred protective immunity against subsequent challenge with the reference strain (SS1). Direct inoculation of H. pylori into the stomach influenced infection in a short time and, more importantly, in a dose-dependent manner, indicating the usefulness of the developed model for pathophysiology, therapeutic and prophylactic studies., (© 2024. Published by The Company of Biologists Ltd.)
- Published
- 2024
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23. Controlling the bacterial load of Salmonella Typhi in an experimental mouse model by a lytic Salmonella phage STWB21: a phage therapy approach.
- Author
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Mondal P, Halder P, Mallick B, Bhaumik S, Koley H, Dutta S, and Dutta M
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- Animals, Mice, Salmonella typhi, Bacterial Load, Mammals, Phage Therapy, Typhoid Fever therapy, Typhoid Fever microbiology, Salmonella Infections therapy, Bacteriophages, Salmonella Phages
- Abstract
Background: Salmonella enterica serotype Typhi is one of the major pathogens causing typhoid fever and a public health burden worldwide. Recently, the increasing number of multidrug-resistant strains of Salmonella spp. has made this utmost necessary to consider bacteriophages as a potential alternative to antibiotics for S. Typhi infection treatment. Salmonella phage STWB21, isolated from environmental water, has earlier been reported to be effective as a safe biocontrol agent by our group. In this study, we evaluated the efficacy of phage STWB21 in reducing the burden of salmonellosis in a mammalian host by inhibiting Salmonella Typhi invasion into the liver and spleen tissue., Results: Phage treatment significantly improved the survival percentage of infected mice. This study also demonstrated that oral administration of phage treatment could be beneficial in both preventive and therapeutic treatment of salmonellosis caused by S. Typhi. Altogether the result showed that the phage treatment could control tissue inflammation in mice before and after Salmonella infection., Conclusions: To the best of our knowledge, this is the first report of phage therapy in a mouse model against a clinically isolated Salmonella Typhi strain that includes direct visualization of histopathology and ultrathin section microscopy images from the liver and spleen sections., (© 2023. The Author(s).)
- Published
- 2023
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24. Pentavalent outer membrane vesicles immunized mice sera confers passive protection against five prevalent pathotypes of diarrhoeagenic Escherichia coli in neonatal mice.
- Author
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Banerjee S, Halder P, Das S, Maiti S, Bhaumik U, Dutta M, Chowdhury G, Kitahara K, Miyoshi SI, Mukhopadhyay AK, Dutta S, and Koley H
- Subjects
- Humans, Adult, Animals, Mice, Child, Animals, Newborn, Immunity, Humoral, Escherichia coli, Lipopolysaccharides, Diarrhea
- Abstract
Diarrhoeagenic Escherichia coli (DEC) pathotypes are one of the major causative agents of diarrhoea induced childhood morbidity and mortality in developing countries. Licensed vaccines providing broad spectrum protection against DEC mediated infections are not available. Outer membrane vesicles (OMVs) are microvesicles released by gram-negative bacteria during the growth phase and contain multiple immunogenic proteins. Based on prevalence of infections, we have formulated a pentavalent outer-membrane vesicles (POMVs) based immunogen targeting five main pathotypes of DEC responsible for diarrhoeal diseases. Following isolation, OMVs from five DEC pathotypes were mixed in equal proportions to formulate POMVs and 10 µg of the immunogen was intraperitoneally administered to adult BALB/c mice. Three doses of POMVs induced significant humoral immune response against whole cell lysates (WCLs), outer membrane proteins (OMPs) and lipopolysaccharides (LPS) isolated from DEC pathotypes along with significant induction of cellular immune response in adult mice. Passive transfer of POMVs immunized adult mice sera protected neonatal mice significantly against DEC infections. Overall, this study finds POMVs to be immunogenic in conferring broad-spectrum passive protection to neonatal mice against five main DEC pathotypes. Altogether, these findings suggest that POMVs can be used as a potent vaccine candidate to ameliorate the DEC-mediated health burden., Competing Interests: Declaration of Competing Interest The authors declare no financial or personal conflicts of interest., (Copyright © 2023. Published by Elsevier B.V.)
- Published
- 2023
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25. Bacterial ghost cell based bivalent candidate vaccine against Salmonella Typhi and Salmonella Paratyphi A: A prophylactic study in BALB/c mice.
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Halder P, Maiti S, Banerjee S, Das S, Dutta M, Dutta S, and Koley H
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- Mice, Animals, Salmonella typhi, Salmonella paratyphi A, Mice, Inbred BALB C, Typhoid Fever prevention & control, Typhoid-Paratyphoid Vaccines
- Abstract
Typhoid and emerging paratyphoid fever are a severe enteric disease worldwide with high morbidity and mortality. Licensed typhoid vaccines are in the market, but no paratyphoid vaccine is currently available. In the present study we developed a bivalent vaccine against Salmonella Typhi and Paratyphi A using a bacterial ghost platform. Bacterial ghost cells (BGs) are bacteria-derived cell membranes without cytoplasmic contents that retain their cellular morphology, including all cell surface features. Furthermore, BGs have inherent adjuvant properties that promote an enhanced humoral and cellular immune reaction to the target antigen. Sodium hydroxide was used to prepare ghost cells of Salmonella Typhi and Paratyphi A. The bacterial ghost cells were characterised using electron microscopy. Then BALB/c mice were immunized three times (0
th , 14th and 28th day) with the bivalent typhoidal bacterial ghost cells. Haematological study of adult mice throughout immunization period reflected that the immunogen was safe to administer and does not affect the animals' health. After complete immunization, we found significant serum antibody titter against whole cell lysate, outer membrane protein and lipopolysaccharide of both bacteria, and cell-mediated immunity was observed in an ex-vivo experiment. CD4+, CD8a+ and CD19+ splenic cell populations were increased in immunized animals. Bivalent Typhoidal ghost cell immunized mice showed better survival, less bacterial colonization in systemic organs, and less inflammation and/or destruction of tissue in histopathological analysis than non-immunized control mice.Serum antibodies of immunized animals can significantly inhibit bacterial motility and mucin penetration ability with better killing properties against Salmonella Typhi and Paratyphi A. Furthermore, significant passive protection was observed through the adoptive transfer of serum antibody and lymphocytes of immunized animals to naïve animals after bacterial infection. In summary, Bivalent Typhoidal Bacterial Ghost cells (BTBGs) enhances immunogenic properties and serves as a safe and effective prevention strategy against Salmonella Typhi and Paratyphi A., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)- Published
- 2023
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26. A tetravalent Shigella outer membrane vesicles based candidate vaccine offered cross-protection against all the serogroups of Shigella in adult mice.
- Author
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Bhaumik U, Halder P, Howlader DR, Banerjee S, Maiti S, Dutta S, and Koley H
- Subjects
- Animals, Adult, Humans, Mice, Serogroup, Shigella flexneri, Antibodies, Bacterial, Shigella Vaccines, Shigella, Dysentery, Bacillary prevention & control, Dysentery, Bacillary microbiology, Vaccines
- Abstract
In today's world and mostly in low and middle income countries, Shigella flexneri and Shigella sonnei remains the major causative agent of clinical bacillary dysentery. Based on contemporary epidemiology, a tetravalent Outer Membrane Vesicle (OMVs) based immunogen was formulated using the most commonly circulating Shigella strains, namely, S. flexneri 2a, S. flexneri 3a, S. flexneri 6 and S. sonnei I, in a 1:1:1:1 ratio. Adult BALB/c mice were orally immunized in a prime-boost-boost manner. Tetravalent Shigella OMVs immunogen induced significant and persistent serum and mucosal antibodies against OMVs, Outer Membrane Proteins (OMPs) and lipopolysaccharides (LPS). Tetravalent OMVs also primed cell mediated immune response effectively. Protective efficacy against six heterologous Shigella strains was checked in an intra-peritoneal mouse model. Immunized mice survived lethal infection better than the non-immunized mice cohort with fewer replicating bacteria isolated from their gut. This study establishes the possibilities of tetravalent OMVs immunogen to become a potent vaccine candidate against human shigellosis, overcoming the limitations of sero-specific cross-protection of Shigella species., Competing Interests: Declaration of competing interest The authors have no conflict of interest to proclaim., (Copyright © 2023 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)
- Published
- 2023
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27. Cloning, improved expression and purification of invasion plasmid antigen D (IpaD): an effector protein of enteroinvasive Escherichia coli (EIEC).
- Author
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Halder S, Jaiswal N, Koley H, and Mahata N
- Abstract
The widespread increase in broad-spectrum antimicrobial resistance is making it more difficult to treat gastrointestinal infections. Enteroinvasive Escherichia coli is a prominent etiological agent of bacillary dysentery, invading via the fecal-oral route and exerting virulence on the host via the type III secretion system. IpaD, a surface-exposed protein on the T3SS tip that is conserved among EIEC and Shigella , may serve as a broad immunogen for bacillary dysentery protection. For the first time, we present an effective framework for improving the expression level and yield of IpaD in the soluble fraction for easy recovery, as well as ideal storage conditions, which may aid in the development of new protein therapies for gastrointestinal infections in the future. To achieve this, uncharacterized full length IpaD gene from EIEC was cloned into pHis-TEV vector and induction parameters were optimized for enhanced expression in the soluble fraction. After affinity-chromatography based purification, 61% pure protein with a yield of 0.33 mg per litre of culture was obtained. The purified IpaD was retained its secondary structure with a prominent α-helical structure as well as functional activity during storage, at 4°C, -20°C and -80°C using 5% sucrose as cryoprotectants, which is a critical criterion for protein-based treatments.
- Published
- 2023
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28. Genomic insights into extensively drug-resistant Pseudomonas aeruginosa isolated from a diarrhea case in Kolkata, India.
- Author
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Chowdhury G, Das B, Kumar S, Pant A, Mukherjee P, Ghosh D, Koley H, Miyoshi SI, Okamoto K, Paul A, Dutta S, Ramamurthy T, and Mukhopadyay AK
- Subjects
- Humans, Anti-Bacterial Agents pharmacology, Anti-Bacterial Agents metabolism, Genomics, Virulence genetics, Diarrhea, Drug Resistance, Multiple, Bacterial genetics, Microbial Sensitivity Tests, Pseudomonas aeruginosa metabolism, Pseudomonas Infections drug therapy, Pseudomonas Infections metabolism
- Abstract
Aim: To characterize extensively drug-resistant Pseudomonas aeruginosa from a patient with diarrhea. Materials & methods: Antimicrobial susceptibility was tested by the disk diffusion method. The P. aeruginosa genome was sequenced to identify virulence, antibiotic resistance and prophages encoding genes. Results: P. aeruginosa had a wide spectrum of resistance to antibiotics. Genomic analysis of P. aeruginosa revealed 76 genes associated with antimicrobial resistance, xenobiotic degradation and the type three secretion system. Conclusion: This is the first report on diarrhea associated with P. aeruginosa . Since no other organism was identified, the authors assume that the patient had dysbiosis due to antibiotic exposure, leading to antibiotic-associated diarrhea. The in vivo toxicity expressed by the pathogen may be associated with T3SS.
- Published
- 2023
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29. Facile synthesis of multi-faceted, biomimetic and cross-protective nanoparticle-based vaccines for drug-resistant Shigella: a flexible platform technology.
- Author
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Baruah N, Ahamad N, Halder P, Koley H, and Katti DS
- Subjects
- Animals, Mice, Pharmaceutical Preparations, Biomimetics, Adjuvants, Immunologic, Antibodies, Bacterial, Mice, Inbred BALB C, Shigella, Shigella Vaccines genetics, Nanoparticles
- Abstract
Background: No commercial vaccines are available against drug-resistant Shigella due to serotype-specific/narrow-range of protection. Nanoparticle-based biomimetic vaccines involving stable, conserved, immunogenic proteins fabricated using facile chemistries can help formulate a translatable cross-protective Shigella vaccine. Such systems can also negate cold-chain transportation/storage thus overcoming challenges prevalent in various settings., Methods: We explored facile development of biomimetic poly (lactide-co-glycolide)/PLGA 50:50 based nanovaccines (NVs), encapsulating conserved stabilized antigen(s)/immunostimulant of S. dysenteriae 1 origin surface-modified using simple chemistries. All encapsulants (IpaC/IpaB/LPS) and nanoparticles (NPs)-bare and modified (NV), were thoroughly characterized. Effect of IpaC on cellular uptake of NPs was assessed in-vitro. Immunogenicity of the NVs was assessed in-vivo in BALB/c mice by intranasal immunization. Cross-protective efficacy was assessed by intraperitoneally challenging the immunized groups with a high dose of heterologous S. flexneri 2a and observing for visible diarrhea, weight loss and survival. Passive-protective ability of the simplest NV was assessed in the 5-day old progeny of vaccinated mice., Results: All the antigens and immunostimulant to be encapsulated were successfully purified and found to be stable both before and after encapsulation into NPs. The ~ 300 nm sized NPs with a zeta potential of ~ - 25 mV released ~ 60% antigen by 14th day suggesting an appropriate delivery kinetics. The NPs could be successfully surface-modified with IpaC and/or CpG DNA. In vitro experiments revealed that the presence of IpaC can significantly increase cellular uptake of NPs. All NVs were found to be cytocompatible and highly immunogenic. Antibodies in sera of NV-immunized mice could recognize heterologous Shigella. Immunized sera also showed high antibody and cytokine response. The immunized groups were protected from diarrhea and weight loss with ~ 70-80% survival upon heterologous Shigella challenge. The simplest NV showed ~ 88% survival in neonates., Conclusions: Facile formulation of biomimetic NVs can result in significant cross-protection. Further, passive protection in neonates suggest that parental immunization could protect infants, the most vulnerable group in context of Shigella infection. Non-invasive route of vaccination can also lead to greater patient compliance making it amenable for mass-immunization. Overall, our work contributes towards a yet to be reported platform technology for facile development of cross-protective Shigella vaccines., (© 2023. The Author(s).)
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- 2023
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30. Suppression of classical nuclear import pathway by importazole and ivermectin inhibits rotavirus replication.
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Sarkar R, Banerjee S, Halder P, Koley H, Komoto S, and Chawla-Sarkar M
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- Animals, Mice, Active Transport, Cell Nucleus, Ivermectin pharmacology, Karyopherins metabolism, Viral Proteins, Rotavirus drug effects, Rotavirus physiology, Virus Replication, Rotavirus Infections drug therapy
- Abstract
Background: Rotavirus is the foremost cause of acute gastroenteritis among infants in resource-poor countries, causing severe morbidity and mortality. The currently available rotavirus vaccines are effective in reducing severity of the disease but not the infection rates, thus antivirals as an adjunct therapy are needed to reduce the morbidity in children. Viruses rely on host cellular machinery for nearly every step of the replication cycle. Therefore, targeting host factors that are indispensable for virus replication could be a promising strategy., Objectives: To assess the therapeutic potential of ivermectin and importazole against rotaviruses., Methods: Antirotaviral activity of importazole and ivermectin was measured against various rotavirus strains (RV-SA11, RV-Wa, RV-A5-13, RV-EW) in vitro and in vivo by quantifying viral protein expression by western blot, analysing viroplasm formation by confocal microscopy, and measuring virus yield by plaque assay., Results: Importin-β1 and Ran were found to be induced during rotavirus infection. Knocking down importin-β1 severely impaired rotavirus replication, suggesting a critical role for importin-β1 in the rotavirus life cycle. In vitro studies revealed that treatment of ivermectin and importazole resulted in reduced synthesis of viral proteins, diminished production of infectious virus particles, and decrease in viroplasm-positive cells. Mechanistic study proved that both drugs perform antirotavirus activity by inhibiting the function of importin-β1. In vivo investigations in mice also confirmed the antirotavirus potential of importazole and ivermectin at non-toxic doses. Treatments of rotavirus-infected mice with either drug resulted in diminished shedding of viral particles in the stool sample, reduced expression of viral protein in the small intestine and restoration of damaged intestinal villi comapared to untreated infected mice., Conclusions: The study highlights the potential of importazole and ivermectin as antirotavirus therapeutics., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2022
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31. Stable Recombinant Invasion Plasmid Antigen C (IpaC)-Based Single Dose Nanovaccine for Shigellosis.
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Baruah N, Halder P, Koley H, and Katti DS
- Subjects
- Mice, Animals, Antigens, Bacterial genetics, Antibodies, Bacterial, Plasmids genetics, Mice, Inbred BALB C, Diarrhea, Dysentery, Bacillary prevention & control
- Abstract
Shigellosis, caused by the bacteria Shigella , is the leading cause of bacterial diarrhea and the second leading cause of diarrheal death among children under the age of five. Unfortunately, Shigella strains have acquired resistance to antibiotics, and a commercial vaccine is yet to be available. We have previously demonstrated that Shigella dysenteriae serotype 1 (Sd1)-based recombinant, stabilized, "invasion plasmid antigen C" (IpaC; 42 kDa) protein can induce robust immune responses in BALB/c mice against a challenge of a high dose of heterologous Shigella when immunized via three intranasal doses of IpaC without an adjuvant. In this work, in order to reduce the frequency of dosing and increase possible patient compliance, based on our previous screening, the minimum protective dose of stabilized IpaC (20 μg) was encapsulated in biodegradable polymeric poly(lactide- co -glycolide) nanoparticles (∼370 nm) and intranasally administered in BALB/c mice in a single dose. Interestingly, a single intranasal dose of the developed vaccine particles encapsulating only 20 μg of Sd1 IpaC led to a temporal increase in the antibody production with an improved cytokine response compared to free IpaC administered three times as described in our previous report. Upon intraperitoneal challenge with a high dose of heterologous Shigella flexneri 2a (common in circulation), the immunized animals were protected from diarrhea, lethargy, and weight loss with ∼67% survival, while all the control animals died by 36 h of the challenge. Overall, the developed nanovaccine could be explored as a potential noninvasive, cross-protective, single-dose, single-antigen Shigella vaccine amenable for scale-up and eventual mass immunization.
- Published
- 2022
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32. Protective efficacy of fish oil nanoemulsion against non-typhoidal Salmonella mediated mucosal inflammation and loss of barrier function.
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Dey TK, Bose P, Paul S, Karmakar BC, Saha RN, Gope A, Koley H, Ghosh A, Dutta S, Dhar P, and Mukhopadhyay AK
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- Animals, Caco-2 Cells, Cytokines metabolism, Dextrans, Emulsions metabolism, Fatty Acids, Unsaturated metabolism, Fish Oils metabolism, Fish Oils pharmacology, Fluorescein-5-isothiocyanate analogs & derivatives, Humans, Inflammation drug therapy, Inflammation metabolism, Intestinal Mucosa metabolism, Mammals, Mice, Salmonella typhimurium, Streptomycin metabolism, Water metabolism, Mucositis, Salmonella enterica
- Abstract
Non-typhoidal Salmonella serotypes are well adapted to utilize the inflammation for colonization in the mammalian gut mucosa and cause loss of the integrity of the epithelial barrier in the mammalian intestine. The present study assessed the protective efficacy of fish oil-in-water nanoemulsion, compared to the conventional emulsion, towards the intestinal epithelial barrier against invasive infection of Salmonella enterica serovar Typhimurium strain SL1344 in an in vivo streptomycin-treated mouse model. Non-typhoidal Salmonella enterica serovar Typhimurium strain SL1344 expresses its invasiveness by creating extreme inflammatory assault in the mammalian host lumen via its repertoire of secretory or membrane-bound proteins. Prophylactic treatment of ω-3 polyunsaturated fatty acid-rich fish oil nanoemulsion not only reduced the inflammatory markers by 4-5 fold against the established infection but also retained the gut barrier efficiency as shown by FITC-dextran permeability assay. Though the conventional emulsion also showed similar trends, the efficacy was significantly better with nanoemulsion treatment but neither the nanoemulsion nor conventional emulsion caused any significant change in the microbial colonization of the murine gut mucosa. Mechanistic assessment of the nanoemulsion against inflammation and invasion across the Caco-2 cell monolayer revealed that nanoemulsion treatment protected the expression of Zona occludens-1 along the tight junction, almost by 3-fold as compared to the infected cell monolayer. Such protection was evinced by the trans-epithelial electrical resistance value and the FITC-dextran permeability analysis as well. Fish oil nanoemulsion treatment has also shown significant reduction in pro-inflammatory cytokine expression by the Salmonella strain SL1344 infected Caco-2 cell monolayer. Conventional emulsion also showed distinct protection, but the nanoemulsion offered better protection at the same dosage of fish oil, probably due to its better bioavailability. The results proved that fish oil-loaded nanoemulsion can be efficacious towards maintaining the barrier function and protecting against systemic bacteremia during invasive intestinal infection.
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- 2022
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33. Quercetin, a flavonoid, combats rotavirus infection by deactivating rotavirus-induced pro-survival NF-κB pathway.
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Banerjee S, Sarkar R, Mukherjee A, Miyoshi SI, Kitahara K, Halder P, Koley H, and Chawla-Sarkar M
- Abstract
Rotavirus (RV) is the leading cause of acute gastroenteritis and watery diarrhea in children under 5 years accounting for high morbidity and mortality in countries with poor socioeconomic status. Although vaccination against RV has been implemented in more than 100 countries, the efficacy of vaccine has been challenged in low-income settings. The lack of any FDA-approved drug against RV is an additional concern regarding the treatment associated with rotavirus-induced infantile death. With the purpose for the discovery of anti-RV therapeutics, we assessed anti-rotaviral potential of quercetin, a well-characterized antioxidant flavonoid. In vitro study revealed that quercetin treatment resulted in diminished production of RV-SA11 (simian strain) viral particles in a concentration-dependent manner as estimated by the plaque assay. Consistent with this result, Western blot analysis also revealed reduced synthesis of viral protein in quercetin-treated RV-SA11-infected MA104 cells compared to vehicle (DMSO) treated controls. Not surprisingly, infection of other RV strains A5-13 (bovine strain) and Wa (Human strain) was also found to be abridged in the presence of quercetin compared to DMSO. The IC
50 of quercetin against three RV strains ranges between 2.79 and 4.36 Mm, and S.I. index is greater than 45. Concurrent to the in vitro results, in vivo study in mice model also demonstrated reduced expression of viral proteins and viral titer in the small intestine of quercetin-treated infected mice compared to vehicle-treated infected mice. Furthermore, the result suggested anti-rotaviral activity of quercetin to be interferon-independent. Mechanistic study revealed that the antiviral action of quercetin is co-related with the inhibition of RV-induced early activation of NF-κB pathway. Overall, this study delineates the strong anti-RV potential of quercetin and also proposes it as future therapeutics against rotaviral diarrhea., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Banerjee, Sarkar, Mukherjee, Miyoshi, Kitahara, Halder, Koley and Chawla-Sarkar.)- Published
- 2022
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34. An Experimental Adult Zebrafish Model for Shigella Pathogenesis, Transmission, and Vaccine Efficacy Studies.
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Howlader DR, Bhaumik U, Halder P, Satpathy A, Sarkar S, Ghoshal M, Maiti S, Withey JH, Mitobe J, Dutta S, and Koley H
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- Animals, Disease Models, Animal, Mammals, Vaccine Efficacy, Water, Zebrafish microbiology, Dysentery, Bacillary, Shigella
- Abstract
Shigellosis has been a menace to society for ages. The absence of an effective vaccine against Shigella , improper sanitation, and unhygienic use of food and water allow the disease to flourish. Shigella can also be transmitted via natural water bodies. In the absence of a good animal model, the actual nature of pathogenesis and transmission remains unclear. Zebrafish larvae have previously been described as a model for Shigella pathogenesis. However, larval fish lack a mature intestinal microbiota and immune system. Here, the adult zebrafish was assessed as a potential model for Shigella pathogenesis. Their well-developed innate and adaptive immune responses mimic the mammalian immune system. Shigella showed a clear dose-, time-, and temperature-dependent colonization of the adult zebrafish gut. Efficacy of a three-dose immunization regime was tested using bath immunization with heat-killed trivalent Shigella immunogen. The present study demonstrates the efficacy of an adult zebrafish model for pathogenesis, transmission, and vaccine efficacy studies. IMPORTANCE Shigellosis is a diarrheal disease that is prevalent in developing countries and especially dangerous in young children. Currently, animal models for shigellosis are unable to model some aspects of the infectious cycle. Here, we describe a new shigellosis model in adult zebrafish, an increasingly common model organism for studying bacterial pathogens. The zebrafish model can be used to study Shigella colonization, transmission, and immune responses, as well as test vaccine efficacy.
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- 2022
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35. Development of a novel trivalent invasive non-typhoidal Salmonella outer membrane vesicles based vaccine against salmonellosis and fowl typhoid in chickens.
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Maiti S, Halder P, Banerjee S, Dutta M, Kumar Mukhopadhyay A, Dutta S, and Koley H
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- Animals, Chickens, Salmonella enteritidis, Poultry Diseases prevention & control, Salmonella Infections, Animal prevention & control, Salmonella Vaccines, Typhoid Fever
- Abstract
Poultry animals act as natural reservoirs of invasive non-typhoidal Salmonella [iNTS] serovars and consumption of iNTS contaminated poultry meat and eggs is one of the major sources of iNTS infection in developed and developing countries. Irrational use of antibiotics in the poultry industry gives rise to the global emergence of multi drug resistant iNTS strains. Among different strategies to control iNTS infection in poultry farms, vaccination is now being widely used. There are several licensed vaccines available in the market for poultry animals to ameliorate iNTS infection but none of them have broad spectrum protective efficacy. In this study we have formulated a single novel trivalent iNTS outer membrane vesicles [OMVs] based immunogen which can confer long term broad spectrum protection against most prevalent iNTS serovars. We have isolated OMVs from Salmonella Typhimurium [ST], Salmonella Enteritidis [SE], and Salmonella Gallinarum [SG] and formulated the trivalent immunogen by mixing OMVs in a 1:1:1 ratio. One day old chicks were immunized thrice via oral route at two week intervals. Vaccination significantly induced serovar specific antibodies detected up to 180 days post immunization. Post challenge with both homologous and heterologous [S. Infantis] serovars, immunized birds showed reduced level of fecal shedding and organ invasion. A long term efficacy study also showed reduced levels of tissue invasion up to one year post immunization. These results demonstrate that our novel formulation of immunogen could be a broad spectrum potential vaccine for both layer and broiler breeds against iNTS mediated salmonellosis and fowl typhoid., (Copyright © 2022 Elsevier GmbH. All rights reserved.)
- Published
- 2022
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36. Development of a Self-Adjuvanting, Cross-Protective, Stable Intranasal Recombinant Vaccine for Shigellosis.
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Baruah N, Ahamad N, Maiti S, Howlader DR, Bhaumik U, Patil VV, Chakrabarti MK, Koley H, and Katti DS
- Subjects
- Administration, Intranasal, Animals, Mice, Vaccines, Synthetic genetics, Dysentery, Bacillary prevention & control, Shigella genetics, Shigella Vaccines genetics
- Abstract
With the acquirement of antibiotic resistance, Shigella has resulted in multiple epidemics of shigellosis, an infectious diarrheal disease, causing thousands of deaths per year. Unfortunately, there are no licensed vaccines, primarily due to low or serotype-specific immunogenicity. Thus, conserved subunit vaccines utilizing recombinant invasion plasmid antigens (Ipa) have been explored as cross-protective vaccine candidates. However, achieving cross-protection against Shigella dysenteriae 1, which caused multiple pandemics/epidemics in the recent past, has been difficult. Therefore, a rational approach to improve cross-protection in the preparation for a possible pandemic should involve conserved proteins from S. dysenteriae 1 (Sd1). IpaC is one such conserved immunogenic protein that is less explored as an independent vaccine due to its instability/aggregation. Therefore, to improve cross-protection and potential immunogenicity and to be prepared for a future epidemic/pandemic, herein, we stabilized recombinant Sd1 IpaC, expressed without its chaperone, using a previously reported stabilizing detergent (LDAO) in a modified protocol and assessed its vaccine potential without an adjuvant. The protein assembled into heterogeneous complex spherical structures in the presence of LDAO and showed improved stability at storage temperatures of -80, -20, 4, 25, and 37 °C while providing enhanced yield and concentration. The protein could also be stably lyophilized and reconstituted, increasing the convenience of transportation and storage. Upon intranasal administration in BALB/c mice, the stabilized-IpaC-immunized groups generated significant antibody response and were not only protected against a high intraperitoneal dose of homologous S. dysenteriae 1 but also showed 100% survival against heterologous Shigella flexneri 2a without an adjuvant, while the control animals showed visible diarrhea (bloody-Sd1 challenge), lethargy, and weight loss with 0% survival. Overall, this work demonstrates that stabilized IpaC can be explored as a minimalist, self-adjuvanting, cross-protective, intranasal, single-antigen Shigella vaccine.
- Published
- 2021
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37. Virulence of Cholera Toxin Gene-Positive Vibrio cholerae Non-O1/non-O139 Strains Isolated From Environmental Water in Kolkata, India.
- Author
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Takahashi E, Ochi S, Mizuno T, Morita D, Morita M, Ohnishi M, Koley H, Dutta M, Chowdhury G, Mukhopadhyay AK, Dutta S, Miyoshi SI, and Okamoto K
- Abstract
Cholera toxin (CT)-producing Vibrio cholerae O1 and O139 cause acute diarrheal disease and are proven etiological agents of cholera epidemics and pandemics. On the other hand, V. cholerae non-O1/non-O139 are designated as non-agglutinable (NAG) vibrios and are not associated with epidemic cholera. The majority of NAG vibrios do not possess the gene for CT ( ctx ). In this study, we isolated three NAG strains (strains No. 1, 2, and 3) with ctx from pond water in Kolkata, India, and examined their pathogenic properties. The enterotoxicity of the three NAG strains in vivo was examined using the rabbit ileal intestinal loop test. Strain No. 1 induced the accumulation of fluid in the loop, and the volume of fluid was reduced by simultaneous administration of anti-CT antiserum into the loop. The volume of fluid in the loop caused by strains No. 2 and 3 was small and undetectable, respectively. Then, we cultured these three strains in liquid medium in vitro at two temperatures, 25°C and 37°C, and examined the amount of CT accumulated in the culture supernatant. CT was accumulated in the culture supernatant of strain No.1 when the strain was cultured at 25°C, but that was low when cultured at 37°C. The CT amount accumulated in the culture supernatants of the No. 2 and No. 3 strains was extremely low at both temperature under culture conditions examined. In order to clarify the virulence properties of these strains, genome sequences of the three strains were analyzed. The analysis showed that there was no noticeable difference among three isolates both in the genes for virulence factors and regulatory genes of ctx . However, vibrio seventh pandemic island-II (VSP-II) was retained in strain No. 1, but not in strains No. 2 or 3. Furthermore, it was revealed that the genotype of the B subunit of CT in strain No. 1 was type 1 and those of strains No. 2 and 3 were type 8. Histopathological examination showed the disappearance of villi in intestinal tissue exposed to strain No. 1. In addition, fluid accumulated in the loop due to the action of strain No. 1 had hemolytic activity. This indicated that strain No. 1 may possesses virulence factors to induce severe syndrome when the strain infects humans, and that some strains of NAG vibrio inhabiting pond water in Kolkata have already acquired virulence, which can cause illness in humans. There is a possibility that these virulent NAG vibrios, which have acquired genes encoding factors involved in virulence of V. cholerae O1, may emerge in various parts of the world and cause epidemics in the future., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Takahashi, Ochi, Mizuno, Morita, Morita, Ohnishi, Koley, Dutta, Chowdhury, Mukhopadhyay, Dutta, Miyoshi and Okamoto.)
- Published
- 2021
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38. Bivalent non-typhoidal Salmonella outer membrane vesicles immunized mice sera confer passive protection against gastroenteritis in a suckling mice model.
- Author
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Maiti S, Howlader DR, Halder P, Bhaumik U, Dutta M, Dutta S, and Koley H
- Subjects
- Animals, Antibodies, Bacterial, Mice, Mice, Inbred BALB C, Salmonella typhimurium, Gastroenteritis prevention & control, Typhoid Fever, Typhoid-Paratyphoid Vaccines
- Abstract
Invasive non-typhoidal Salmonella (iNTS) serovars, especially Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE), cause gastroenteritis worldwide. Due to the emergence of multi-drug resistance in iNTS, a broad-spectrum vaccine is urgently needed for the prevention of iNTS infection. Currently, there is no effective licensed vaccine against iNTS available in the market. We have formulated an outer membrane vesicles (OMVs) based bivalent immunogen as a vaccine candidate to generate broad-spectrum protective immunity against both recently circulating prevalent ST and SE. We have isolated OMVs from ST and SE and formulated the immunogen by mixing both OMVs (1:1 ratio). Three doses of bivalent immunogen significantly induced humoral immune responses against lipopolysaccharides (LPSs) and outer membrane proteins (OMPs) as well as a cell-mediated immune response in adult mice. We also observed that proteins of OMVs act as an adjuvant for generation of high levels of anti-LPS antibodies through T cell activation. We then characterized the one-day old suckling mice model for both ST and SE mediated gastroenteritis and used the model for a passive protection study. In the passive protection study, we found the passive transfer of bivalent OMVs immunized sera significantly reduced ST and SE mediated colonization and gastroenteritis symptoms in the colon of suckling mice compared to non-immunized sera recipients. The overall study demonstrated that OMVs based bivalent vaccine could generate broad-spectrum immunity against prevalent iNTS mediated gastroenteritis. This study also established the suckling mice model as a suitable animal model for vaccine study against iNTS mediated gastroenteritis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
- Published
- 2021
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39. Multifunctional transcription factor CytR of Vibrio cholerae is important for pathogenesis.
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Das S, Chourashi R, Mukherjee P, Gope A, Koley H, Dutta M, Mukhopadhyay AK, Okamoto K, and Chatterjee NS
- Subjects
- Animals, Bacterial Adhesion, Bacterial Proteins genetics, Cholera Toxin metabolism, Flagella metabolism, Gene Expression Regulation, Bacterial, HT29 Cells, Humans, Intestines microbiology, Intestines pathology, Locomotion, Mice, Mucins metabolism, Rabbits, Repressor Proteins genetics, Vibrio cholerae genetics, Vibrio cholerae growth & development, Vibrio cholerae metabolism, Virulence genetics, Bacterial Proteins metabolism, Repressor Proteins metabolism, Vibrio cholerae pathogenicity
- Abstract
Vibrio cholerae, the Gram-negative facultative pathogen, resides in the aquatic environment and infects humans and causes diarrhoeagenic cholera. Although the environment differs drastically, V. cholerae thrives in both of these conditions aptly and chitinases play a vital role in their persistence and nutrient acquisition. Chitinases also play a role in V. cholerae pathogenesis. Chitinases and its downstream chitin utilization genes are regulated by sensor histidine kinase ChiS, which also plays a significant role in pathogenesis. Recent exploration suggests that CytR, a transcription factor of the LacI family in V. cholerae, also regulates chitinase secretion in environmental conditions. Since chitinases and chitinase regulator ChiS is involved in pathogenesis, CytR might also play a significant role in pathogenicity. However, the role of CytR in pathogenesis is yet to be known. This study explores the regulation of CytR on the activation of ChiS in the presence of mucin and its role in pathogenesis. Therefore, we created a CytR isogenic mutant strain of V. cholerae (CytR¯) and found considerably less β-hexosaminidase enzyme production, which is an indicator of ChiS activity. The CytR¯ strain greatly reduced the expression of chitinases chiA1 and chiA2 in mucin-supplemented media. Electron microscopy showed that the CytR¯ strain was aflagellate. The expression of flagellar-synthesis regulatory genes flrB , flrC and class III flagellar-synthesis genes were reduced in the CytR¯ strain. The isogenic CytR mutant showed less growth compared to the wild-type in mucin-supplemented media as well as demonstrated highly retarded motility and reduced mucin-layer penetration. The CytR mutant revealed decreased adherence to the HT-29 cell line. In animal models, reduced fluid accumulation and colonization were observed during infection with the CytR¯ strain due to reduced expression of ctxB , toxT and tcpA . Collectively these data suggest that CytR plays an important role in V. cholerae pathogenesis.
- Published
- 2020
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40. Nonmetabolizable Arabinose Inhibits Vibrio cholerae Growth in M9 Medium with Gluconate as the Sole Carbon Source.
- Author
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Golder T, Mukhopadhyay AK, Koley H, and Nandy RK
- Subjects
- Bacterial Proteins genetics, Carbon metabolism, Cell Proliferation drug effects, Cholera microbiology, Culture Media, Genes, Bacterial, Humans, Serogroup, Vibrio cholerae growth & development, Arabinose pharmacology, Cholera metabolism, Gluconates metabolism, Vibrio cholerae drug effects
- Abstract
The serogroups O1 and O139 of the marine bacterium Vibrio cholerae are responsible for causing cholera in humans. The pentose sugar arabinose is nonmetabolizable by the pathogen and is present in environmental niches as well as in the human intestine. In this study, arabinose-mediated V. cholerae growth interference was assessed in M9 minimal medium containing gluconate as the sole carbon source in the light of Entner-Doudoroff (ED) pathway, an obligatory metabolic route for gluconate utilization. V. cholerae O1 and O139 strains failed to grow in the presence of ≥ 0.3% arabinose in M9 with 0.2% gluconate, but there was no growth inhibition in the presence of arabinose in M9 with 0.2% glucose. Transcriptional analysis of edd and eda, the genes constituting the ED pathway, showed ~100- and ~17-fold increases, respectively, in M9-gluconate. Minor increases of ~4- and ~2-fold for edd and eda, respectively, were noted in AKI medium supplemented with 0.5% arabinose. The observed arabinose-mediated growth inhibition can contribute toward deepening the understanding of altered phenotypes, if any, via complementation/expression studies in V. cholerae with pBAD vectors and arabinose as an inducer.
- Published
- 2020
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41. Molecular insights into the genome dynamics and interactions between core and acquired genomes of Vibrio cholerae .
- Author
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Pant A, Bag S, Saha B, Verma J, Kumar P, Banerjee S, Kumar B, Kumar Y, Desigamani A, Maiti S, Maiti TK, Banerjee SK, Bhadra RK, Koley H, Dutta S, Nair GB, Ramamurthy T, and Das B
- Subjects
- Bacterial Proteins genetics, Conjugation, Genetic genetics, Genetic Engineering, Interspersed Repetitive Sequences genetics, Prophages genetics, Serine Endopeptidases genetics, Vibrio cholerae pathogenicity, Genome, Bacterial genetics, Genomic Islands genetics, Vibrio cholerae genetics
- Abstract
Bacterial species are hosts to horizontally acquired mobile genetic elements (MGEs), which encode virulence, toxin, antimicrobial resistance, and other metabolic functions. The bipartite genome of Vibrio cholerae harbors sporadic and conserved MGEs that contribute in the disease development and survival of the pathogens. For a comprehensive understanding of dynamics of MGEs in the bacterial genome, we engineered the genome of V. cholerae and examined in vitro and in vivo stability of genomic islands (GIs), integrative conjugative elements (ICEs), and prophages. Recombinant vectors carrying the integration module of these GIs, ICE and CTXΦ, helped us to understand the efficiency of integrations of MGEs in the V. cholerae chromosome. We have deleted more than 250 acquired genes from 6 different loci in the V. cholerae chromosome and showed contribution of CTX prophage in the essentiality of SOS response master regulator LexA, which is otherwise not essential for viability in other bacteria, including Escherichia coli In addition, we observed that the core genome-encoded RecA helps CTXΦ to bypass V. cholerae immunity and allow it to replicate in the host bacterium in the presence of similar prophage in the chromosome. Finally, our proteomics analysis reveals the importance of MGEs in modulating the levels of cellular proteome. This study engineered the genome of V. cholerae to remove all of the GIs, ICEs, and prophages and revealed important interactions between core and acquired genomes., Competing Interests: The authors declare no competing interest.
- Published
- 2020
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42. Anti-virulence activity of polyphenolic fraction isolated from Kombucha against Vibrio cholerae.
- Author
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Bhattacharya D, Sinha R, Mukherjee P, Howlader DR, Nag D, Sarkar S, Koley H, Withey JH, and Gachhui R
- Subjects
- Animals, Anti-Bacterial Agents pharmacology, Bacterial Outer Membrane Proteins genetics, Bacterial Outer Membrane Proteins metabolism, Bacterial Proteins drug effects, Catechin pharmacology, Cell Movement drug effects, Cholera drug therapy, Gene Expression drug effects, Intestine, Small drug effects, Intestine, Small microbiology, Mice, Peptide Hydrolases drug effects, Plant Extracts pharmacology, Quercetin analogs & derivatives, Quercetin pharmacology, Rabbits, Vibrio cholerae pathogenicity, Virulence drug effects, Virulence genetics, Virulence Factors genetics, Virulence Factors metabolism, Kombucha Tea, Polyphenols pharmacology, Vibrio cholerae drug effects
- Abstract
The use of traditional foods and beverages or their bioactive compounds as anti-virulence agents is a new alternative method to overcome the increased global emergence of antimicrobial resistance in enteric pathogens. In the present study, we investigated the anti-virulence activity of a polyphenolic fraction previously isolated from Kombucha, a 14-day fermented beverage of sugared black tea, against Vibrio cholerae O1. The isolated fraction was mainly composed of the polyphenols catechin and isorhamnetin. The fraction, the individual polyphenols and the combination of the individual polyphenols significantly inhibited bacterial swarming motility and expression of flagellar regulatory genes motY and flaC, even at sub-inhibitory concentrations. The polyphenolic compounds also decreased bacterial protease secretion and mucin penetration in vitro. In vivo study revealed that the polyphenolic fraction significantly inhibited V. cholerae induced fluid accumulation in the rabbit ileal loop model and intestinal colonization in suckling mice model. Therefore, the anti-virulence activity of the Kombucha polyphenolic fraction involved inhibition of motility and protease secretion of V. cholerae, thus preventing bacterial penetration through the mucin layer as well as fluid accumulation and bacterial colonization in the intestinal epithelial cells. The overall results implied that Kombucha might be considered as a potential alternative source of anti-virulence polyphenols against V. cholerae. To the best of our knowledge, this is the first report on the anti-virulence activity of Kombucha, mostly attributed to its polyphenolic content., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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43. Studies on formulation of a combination heat killed immunogen from diarrheagenic Escherichia coli and Vibrio cholerae in RITARD model.
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Mukherjee P, Mondal V, Bhaumik U, Sinha R, Sarkar S, Mitra S, Howlader DR, Maiti S, Mukhopadhyay AK, Dutta S, and Koley H
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- Animals, Antibodies, Bacterial blood, Antibodies, Bacterial immunology, Antigens, Bacterial immunology, Cholera Vaccines administration & dosage, Cross Protection immunology, Diarrhea microbiology, Disease Models, Animal, Escherichia coli genetics, Escherichia coli Vaccines administration & dosage, Immunization, Immunoglobulins blood, Rabbits, Vaccines, Combined immunology, Vaccines, Inactivated immunology, Vibrio cholerae genetics, Cholera prevention & control, Cholera Vaccines immunology, Diarrhea prevention & control, Escherichia coli immunology, Escherichia coli Infections prevention & control, Escherichia coli Vaccines immunology, Vibrio cholerae immunology
- Abstract
Multiple diarrheagenic enteric bacterial infections cause global morbidity and mortality. A combination vaccine is needed to combat different diarrhea-causing organisms. In our present work, we formulated a combination of antigens from three different diarrheagenic Escherichia coli strains and three different Vibrio cholerae strains. We demonstrated that our newly formulated combination immunogen was able to raise species-specific immunogenicity. This formulation also gave protection against different diarrheagenic E. coli strains in the removable intestinal tie-adult rabbit diarrhea model. However, protective efficacy was not found against the V. cholerae El Tor Ogawa Haitian variant, but challenged with V. cholerae El Tor Inaba or O139 showed protection in rabbits. This is the first report of a single formulated nonliving heat-killed combination immunogen from different diarrheagenic E. coli and V. cholerae that could bestow protection against different bacteria in an animal model., (Copyright © 2019 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)
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- 2019
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44. Hepatoprotective effects of synbiotic soy yogurt on mice fed a high-cholesterol diet.
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Sengupta S, Koley H, Dutta S, and Bhowal J
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- Animals, Diet adverse effects, Diet methods, Hypercholesterolemia etiology, Hypercholesterolemia microbiology, Lipid Peroxidation, Liver metabolism, Liver microbiology, Male, Mice, Mice, Inbred BALB C, Protective Agents pharmacology, Anticholesteremic Agents pharmacology, Hypercholesterolemia therapy, Soy Foods microbiology, Synbiotics administration & dosage, Yogurt microbiology
- Abstract
Objectives: The role of probiotic yogurt in the prevention and treatment of hypercholesterolemia has attracted global attention. Mounting evidence has indicated that probiotics and prebiotics improve lipid metabolism by lowering low-density lipoprotein cholesterol concentration in plasma of hypercholesterolemic patients. The present study aimed to develop synbiotic soy yogurt that had a greater cholesterol-lowering effect in hypercholesterolemic mice compared with control soy yogurt., Methods: Synbiotic soy yogurt was prepared using soy milk and synbiotic capsule containing LactoBacil Plus (SCLBP) probiotic cultures and fructo-oligosaccharide. Synbiotic soy yogurt was analyzed for proximate composition and microbiological and antioxidative properties during storage periods of 28 d. To study hypocholesterolemic effect, hypercholesterolemia was induced in mice with administration of 1.25% cholesterol and 0.5% cholic acid for 4 wk. After that 24 male Balb/c mice were randomly divided into four groups and fed basic, high-cholesterol, high-cholesterol with soy yogurt, or high-cholesterol with synbiotic soy yogurt diet for 5 wk. Blood samples were collected to measure lipids concentration and oxidative and antioxidative status., Results: Proximate composition of SCLBP-formulated soy yogurt exhibits a marked difference from control soy yogurt in terms of total solids, moisture, protein, fat, ash, carbohydrate, and energy content. Results indicated that the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (75.28%) in synbiotic yogurt containing 2% SCLBP was significantly greater (P ≤ 0.05) compared with control soy yogurt (52.98%). In mice with hypercholesterolemia that were fed synbiotic soy yogurts, the yogurts had a favorable effect in reducing blood cholesterol, triglycerides, and low-density lipoprotein cholesterol and lipid peroxidation in liver. These led to a significant decrease of the atherogenic index compared with soy yogurt (control) only. Treatment with synbiotic soy yogurt cultures ameliorates lipid peroxidation in liver., Conclusions: These results indicated that the synbiotic soy yogurts have beneficial effects against hypercholesteroemia and can be used as a therapeutic agent in hypercholesteremic patients., (Copyright © 2019 Elsevier Inc. All rights reserved.)
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- 2019
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45. In vivo fluid accumulation-inhibitory, anticolonization and anti-inflammatory and in vitro biofilm-inhibitory activities of methyl gallate isolated from Terminalia chebula against fluoroquinolones resistant Vibrio cholerae.
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Bag PK, Roy N, Acharyya S, Saha DR, Koley H, Sarkar P, and Bhowmik P
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- Animals, Anti-Bacterial Agents isolation & purification, Cell Membrane drug effects, Cholera microbiology, Disease Models, Animal, Dose-Response Relationship, Drug, Drug Resistance, Multiple, Bacterial drug effects, Gallic Acid administration & dosage, Gallic Acid isolation & purification, Gallic Acid pharmacology, Intestine, Small pathology, Intestine, Small virology, Mice, Mice, Inbred BALB C, Plant Extracts pharmacology, Vibrio cholerae cytology, Vibrio cholerae growth & development, Vibrio cholerae pathogenicity, Anti-Bacterial Agents pharmacology, Anti-Inflammatory Agents pharmacology, Biofilms drug effects, Fluoroquinolones pharmacology, Gallic Acid analogs & derivatives, Terminalia chemistry, Vibrio cholerae drug effects
- Abstract
Acute Vibrio cholerae infection triggers significant inflammatory response and immense fluid secretion in the intestine. In the present study, methyl gallate (MG) isolated from Terminalia chebula was evaluated to determine the in vivo fluid accumulation-inhibitory, anticolonization and anti-inflammatory and in vitro biofilm-inhibitory activities against multi-drug resistant (MDR) V. cholerae. Bacterial membrane-damaging and biofilm-inhibitory activities were determined by membrane perturbation and transmission electron microscopy (TEM); and microdilution assays, respectively. Fluid accumulation-inhibitory and anticolonization activities of MG (23.80-95.23 mg/kg body weight) were determined in 4-5 days old BALB/c mice with an incubation time of 18 h. The effect of MG (1, 50 and 500 mg/kg body weight) on intestinal inflammatory reaction induced by V. cholerae was studied by performing histology in Swiss albino mice. MIC and MBC of MG against the test strains were 32-64 and 64-256 μg/ml, respectively. MG showed the fluid accumulation-inhibitory activity with inhibition values of 42.86-89.08% at doses between 23.80 and 95.23 mg/kg body weight and significant anticolonization activity (p < 0.0001) against V. choleare in the suckling mouse intestine. MG (500 mg/kg body weight) significantly inhibited the inflammatory reactions induced by V. cholerae compared to the vehicle control. MG exhibited 70% minimum biofilm inhibition concentration of 64 μg/ml and bacterial membrane damaging activity at 1 × MBC. The results obtained in the present study suggest that MG has potential as an effective agent for the treatment of severe secretory and inflammatory diarrheal disease caused by MDR V. cholerae., (Copyright © 2018. Published by Elsevier Ltd.)
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- 2019
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46. Effects of nano-sizing on lipid bioaccessibility and ex vivo bioavailability from EPA-DHA rich oil in water nanoemulsion.
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Dey TK, Koley H, Ghosh M, Dey S, and Dhar P
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- Animals, Biological Availability, Dietary Supplements, Docosahexaenoic Acids administration & dosage, Docosahexaenoic Acids pharmacokinetics, Eicosapentaenoic Acid administration & dosage, Eicosapentaenoic Acid pharmacokinetics, Emulsions pharmacokinetics, Fatty Acids, Unsaturated administration & dosage, Fatty Acids, Unsaturated pharmacokinetics, Fish Oils administration & dosage, Intestine, Small drug effects, Leukocytes, Mononuclear drug effects, Lipopolysaccharides pharmacology, Male, Nitric Oxide Synthase Type II antagonists & inhibitors, Pharmaceutical Vehicles chemistry, Pharmaceutical Vehicles pharmacokinetics, Rats, Sprague-Dawley, Emulsions chemistry, Fish Oils pharmacokinetics, Nanostructures chemistry
- Abstract
The physiological efficacy of nutraceuticals is dependent on their physicochemical nature and bioavailability across biological barriers. In the present work, effects of nano-sizing of emulsion-based delivery vehicle on the bioavailability of polyunsaturated fatty acids rich fish oil have been investigated via three-step experimental design; ex vivo rat everted intestinal sac model, cellular lipid uptake and the bioactivity in rat PBMCs. Nanoemulsion in comparison to the conventional emulsion has shown significant higher rate of uptake of polyunsaturated fatty acids in three segments of small intestine. The time-kinetics of such uptake was correlated with appearance of short-chain fatty acids in basal side of the everted sac. The bioavailability of the formulated fish oil and its inhibitory response against lipopolysaccharide-induced nitric oxide production in rat PBMCs were positively correlated. This formulation with nano-sized droplets can be utilized as smart delivery vehicles for designing oral therapies in future., (Copyright © 2018 Elsevier Ltd. All rights reserved.)
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- 2019
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47. Haitian Variant Vibrio cholerae O1 Strains Manifest Higher Virulence in Animal Models.
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Ghosh P, Sinha R, Samanta P, Saha DR, Koley H, Dutta S, Okamoto K, Ghosh A, Ramamurthy T, and Mukhopadhyay AK
- Abstract
Vibrio cholerae causes fatal diarrheal disease cholera in humans due to consumption of contaminated water and food. To instigate the disease, the bacterium must evade the host intestinal innate immune system; penetrate the mucus layer of the small intestine, adhere and multiply on the surface of microvilli and produce toxin(s) through the action of virulence associated genes. V. cholerae O1 that has caused a major cholera outbreak in Haiti contained several unique genetic signatures. These novel traits are used to differentiate them from the canonical El Tor strains. Several studies reported the spread of these Haitian variant strains in different parts of the world including Asia and Africa, but there is a paucity of information on the clinical consequence of these genetic changes. To understand the impact of these changes, we undertook a study involving mice and rabbit models to evaluate the pathogenesis. The colonization ability of Haitian variant strain in comparison to canonical El Tor strain was found to be significantly more in both suckling mice and rabbit model. Adult mice also displayed the same results. Besides that, infection patterns of Haitian variant strains showed a completely different picture. Increased mucosal damaging, colonization, and inflammatory changes were observed through hematoxylin-eosin staining and transmission electron microscopy. Fluid accumulation ability was also significantly higher in rabbit model. Our study indicated that these virulence features of the Haitian variant strain may have some association with the severe clinical outcome of the cholera patients in different parts of the world.
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- 2019
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48. Erratum for Withey et al., "Conjugated Linoleic Acid Reduces Cholera Toxin Production In Vitro and In Vivo by Inhibiting Vibrio cholerae ToxT Activity".
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Withey JH, Nag D, Plecha SC, Sinha R, and Koley H
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- 2019
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49. Development of a novel S. Typhi and Paratyphi A outer membrane vesicles based bivalent vaccine against enteric fever.
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Howlader DR, Koley H, Sinha R, Maiti S, Bhaumik U, Mukherjee P, and Dutta S
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- Animals, Antibodies, Bacterial immunology, Female, Mice, Mice, Inbred BALB C, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Typhoid Fever prevention & control, Salmonella typhi immunology, Typhoid Fever immunology, Typhoid-Paratyphoid Vaccines chemistry
- Abstract
Salmonella Typhi and Salmonella Paratyphi A are the leading causative agents of enteric fever which cause morbidity and mortality worldwide. Currently, there is no combination vaccine which could protect infection from both the strains. In this paper, we are focusing on the development of a novel bivalent typhoidal Outer Membrane Vesicles (OMVs) based immunogen against enteric fever. We have isolated Salmonella Typhi and Paratyphi A OMVs and also characterized OMVs associated antigens. Then we immunized adult mice with three doses of our newly formulated bivalent immunogen orally (25 μg/200 μl). After three doses of oral immunization, we found our immunogen could significantly induce humoral response. We have also found serum IgG against LPS, Vi-polysaccharide etc. OMV immunization induces CD4, CD8 and CD19 population in immunized mice spleen. It also induces Th1 and Th17-cell mediated immunity. We also found bivalent OMVs immunization can prevent more than lethal dose of heterologous Salmonella strains mediated systemic infection in adult mice model. We determined that, the protective immune responses depend on the humoral and cell-mediated immune response. Furthermore, we have evaluated the mode of protective immune response carried out by anti-OMVs antibody by significantly inhibiting bacterial motility and mucin penetration ability. Taken together, these findings suggest that our bivalent immunogen could be used as a novel candidate vaccine against enteric fever., Competing Interests: We have applied for a Patent in the Indian Patent Office. We have received a PCT number which is following: PCT/IN2018/050158. Name of the patent: A Bivalent outer Membrane Vesicles (BOMVs) based vaccine against typhodial salmonellae. Number: PCT/IN2018/050158. Inventors: Hemanta Koley, Debaki Ranjan Howlader, Shanta Dutta. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
- Published
- 2018
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50. Isolation and Characterization of Novel Broad Host Range Bacteriophages of Vibrio cholerae O1 from Bengal.
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Sarkar S, Das M, Bhowmick TS, Koley H, Atterbury R, Chakrabarti AK, and Sarkar BL
- Abstract
Objectives: We have isolated a total of five newer cholera phages which are novel broad host range to incorporate with the existing phage typing schemes for an extended typing scheme., Materials and Methods: These newly isolated phages were well characterized including the electron micrograph. A total of 300 Vibrio cholerae strains were isolated from the different endemic region in India were included in phage typing study., Results: These phages were found different from the existing phages. Electron microscopic results showed that the phages belonged to myophage and podophage group. Characterization of the phages based on pH, temperature, and organic solvent sensitivity showed differences among the phages used in this study. All the strains of Vibrio O1 were typeable (100%) with the five set of cholera phages. Of these, 40% strains were clustered under Type-1., Conclusion: The newer Vibrio phages are novel and broad host range and will be useful to incorporate with the existing phage typing system for more precisely discriminate the strains of Vibrio cholerae., Competing Interests: There are no conflicts of interest.
- Published
- 2018
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