93 research outputs found
Assessment of Antimicrobial Activity of Different Phytochemicals Against Enteric Diseases in Different Animal Models
No full textBiochemical assessment of extract from <em>Oxalis corniculata</em> L.: Its role in food preservation, antimicrobial and antioxidative paradigms using <em>in situ</em> and <em>in vitro</em> models
No full text230-243Food poisoning, often due to microbial contamination and improper storage practice, is a matter of concern. Plants and plant based products are gaining interest in processed food in food industry as an alternative to synthetic antimicrobials. In this context, here, we analysed flavonoid rich methanolic extract from the creeping woodsorrel, Oxalis corniculata L. leaf for its biochemical assessments along with its bioactivity against some common pathogenic bacteria. The bioactivity of the extract as evaluated in both in vitro and in situ methods, verified that the Oxalis corniculata leafextract exert reduces power, hydroxyl radical scavenging activity, inhibition in liposome peroxidation, and DPPH free radical quenching activity. The extract also inhibited the formation of peroxide during subsequent storage in the oil-emulsion system as well as in heated oil. The greater reducing activity of the extract prevented hydroxyl radical induced pUC18 DNA strand breaks and there by retain its original conformation. The extract also prevented the oxidative damage of goat liver cells during Fenton reaction. In vitro antimicrobial experiments implied that extract has inhibitory effect against Staphylococcus aureus, Escherichia coli, Salmonella Typhi, S. Typhiimurium and Vibrio cholera. E. coli showed the highest and V. cholera the lowest sensitivities against the extract. Moreover, the extract can be utilized for preservation of fish meat as it prevented the growth of food poisoning bacteria S. aureus during storage at 10°C. HPLC chromatogram detected the predominance of three active principal components, i.e. flavonoids in the following order: rutin>p-hydroxybenzoic acid>ferulic acid
Antioxidant and Hypocholesterolemic Properties of Functional Soy Yogurts Fortified with ω‐3 and ω‐6 Polyunsaturated Fatty Acids in Balb/c Mice
No full textImmunomodulatory role of outer membrane vesicles of Shigella in mouse model
No full textAbstractIn our previous studies, we discussed the protective efficacy of the two types of vaccine formulation namely SOMVs (single-serotype outer membrane vesicles) and MOMVs (multi-serotype outer membrane vesicles). Here, we compared the immunogenic roles of these two types of formulations and also studied general immunomodulation by Shigella OMVs in adult BALB/c mice. The production of various pro-inflammatory (TNF-α, IL-1β, IL-6, IL-12, IL-18, IFN-γ) and anti-inflammatory (IL-4 and IL-10) cytokine profile were assessed by in vivo, ex vivo and in vitro studies. MOMVs treated mice showed significantly enhanced cytokine production compared to SOMVs treated mice. MOMVs treatment has also upregulated iNOS mRNA synthesis in macrophages. Overall the OMVs of Shigella were found to show a mixed Th1/Th2 response and maintain the balance between pro-inflammation and anti-inflammation in mice. This will be crucial in the development of the next generation OMVs based vaccine against shigellosis
Identification of KDM3A Substrate Preference and Non-canonical Substrates Through Systematic and Rational Peptide Library Screens
No full textJumonji C (JmjC) lysine demethylases (KDMs) are a subfamily of Fe(II)/2-oxoglutarate-dependent dioxygenases which facilitate demethylation of lysine residues by catalyzing hydroxylation of methyl groups attached to the ε-amino group of lysine side chains. Although 24 JmjC KDMs have demonstrated demethylation activity, the current substrate space is largely restricted to several methylation sites within the histone code. However, the biological roles of these enzymes are increasingly being shown to also be attributed to interaction with non-histone proteins. Notably, KDM3A has become relevant to tumour progression due to recent findings of this enzyme’s role in promoting cancerous phenotypes, such as enhanced glucose consumption and upregulated mechanisms of chemoresistance. To aid in uncovering the mechanism(s) by which KDM3A, or other KDMs, impart their oncogenic function(s), this thesis aims to apply peptide library screening to identify novel in vitro substrates and reveal substrate specificity determinants. First, we developed a peptide quantification method to streamline workflows involving large peptide libraries. Second, we developed a general workflow to apply peptide permutation libraries to reveal KDM substrate specificity. Third, we applied a peptide permutation library of histone H3 di-methylated at lysine-9 (i.e., H3K9me2) to KDM3A and revealed (1) the substrate specificity profile of KDM3A and (2) three novel in vitro substrates of this enzyme. Finally, we applied a non-systematic peptide library based on a new hypothesis (a.k.a. Shared Specificity Hypothesis) and uncovered three novel in vitro substrates of KDM3A, of which one substrate was validated in tissue culture models. In compiling a list of all substrates uncovered in this thesis with the few previously known substrates, it became apparent that KDM3A most closely shares substrate specificity with the G9a methyltransferase. Therefore, we anticipate any expansion of the G9a substrate space will organically contribute to KDM3A substrate discovery. Overall, this thesis increased the KDM3A substrate space by 3-fold and revealed critical substrate specificity determinants of this enzyme
197 - Efficacy and Safety of Tram-34 over Zinc in Secretory Diarrhea of Enterotoxin Stimulation
No full textDevelopment of a novel S. Typhi and Paratyphi A outer membrane vesicles based bivalent vaccine against enteric fever
No full textRapid situation & response assessment of diarrhoea outbreak in a coastal district following tropical cyclone AILA in India
No full textBackground & objectives : Cyclone AILA hit Indian States on eastern coast on May 25, 2009. An investigation was conducted to examine if AILA was responsible for increased reporting of diarrhoea cases from the district of East-Medinipur in West Bengal. Identifying causative organisms for diarrhoea and assessing their antibiotic susceptibility profile were other objectives. Methods: Rapid situation and response assessment technique was employed to triangulate primary and secondary data collected through field visits. Prescription audit was also conducted. Results: Significantly increased occurrence of diarrhoea was observed in June 2009 in two subdivisions namely Haldia and Egra (OR 1.6 and 1.3 respectively; 95% CI 1.52-1.65 and 1.21-1.32 P<0.001) considering 2007 as baseline. Vibrio cholerae grew from 54 per cent of the stool samples (21/39; 17 V. cholerae O1-Ogawa and 4 non-O1-non-O139), confirming a community outbreak of cholera. Shigella flexneri 3a was isolated from 5 per cent stool specimens. Increased rate of admission in treatment centres due to diarrhoea in the whole district coincided with the formation of cyclone and showed over two-fold rise compared to the admission recorded 6 days ago. Haldia subdivision had the highest attack rate of 9 per 1000 in the month of June, 2009 whereas for the whole district it was 5 per 1000 in the same month. All the isolates of V. cholerae were resistant to ampicillin and furazolidone and sensitive to norfloxacin and azithromycin. Interpretation & conclusions : Pre-AILA changes in the environment, AILA and seasonality of diarrhoea in the study district interplayed towards increased occurrence of diarrhoea. Continuous tracking of 'seasonality of diarrhoea in the community with vulnerability assessment of potential hosts', 'antibiotic sensitivity profile of the causative microorganisms', and 'prescription practice of physicians' would help appropriate disaster management
An attenuated Shigella mutant lacking the RNA-binding protein Hfq provides cross-protection against Shigella strains of broad serotype.
No full textFew live attenuated vaccines protect against multiple serotypes of bacterial pathogen because host serotype-specific immune responses are limited to the serotype present in the vaccine strain. Here, immunization with a mutant of Shigella flexneri 2a protected guinea pigs against subsequent infection by S. dysenteriae type 1 and S. sonnei strains. This deletion mutant lacked the RNA-binding protein Hfq leading to increased expression of the type III secretion system via loss of regulation, resulting in attenuation of cell viability through repression of stress response sigma factors. Such increased antigen production and simultaneous attenuation were expected to elicit protective immunity against Shigella strains of heterologous serotypes. Thus, the vaccine potential of this mutant was tested in two guinea pig models of shigellosis. Animals vaccinated in the left eye showed fewer symptoms upon subsequent challenge via the right eye, and even survived subsequent intestinal challenge. In addition, oral vaccination effectively induced production of immunoglobulins without severe side effects, again protecting all animals against subsequent intestinal challenge with S. dysenteriae type 1 or S. sonnei strains. Antibodies against common virulence proteins and the O-antigen of S. flexneri 2a were detected by immunofluorescence microscopy. Reaction of antibodies with various strains, including enteroinvasive Escherichia coli, suggested that common virulence proteins induced protective immunity against a range of serotypes. Therefore, vaccination is expected to cover not only the most prevalent serotypes of S. sonnei and S. flexneri 2a, but also various Shigella strains, including S. dysenteriae type 1, which produces Shiga toxin
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