Kuntal Ghosh

Collagen scaffolds derived from fresh water fish origin and their biocompatibility

Collagen, a major component of native extracellular matrix, has diverse biomedical applications. However, its application is limited due to lack of cost-effective production and risk of disease transmission from bovine sources currently utilized. This study describes fabrication and characterization of nano/micro fibrous scaffolds utilizing collagen extracted from fresh water fish origin. This is the first time collagen extracted from fresh water fish origin was studied for their biocompatibility and immunogenicity. The nano/micro fibrous collagen scaffolds were fabricated through self-assembly owing to its amphiphilic nature and were subsequently cross-linked. In vitro degradation study revealed higher stability of the cross-linked scaffolds with only ~50% reduction of mass in 30 days, while the uncross-linked one degraded completely in 4 days. Further, minimal inflammatory response was observed when collagen solution was injected in mice with or without adjuvant, without significant dilution of sera. The fish collagen scaffolds exhibited considerable cell viability and were comparable with that of bovine collagen. SEM and fluorescence microscopic analysis revealed significant proliferation rate of cells on the scaffolds and within 5 days the cells were fully confluent. These findings indicated that fish collagen scaffolds derived from fresh water origin were highly biocompatible in nature.

Microbial, saccharifying and antioxidant properties of an Indian rice based fermented beverage.

Haria, a popular rice based ethnic fermented beverage, is consumed as a staple food and refreshing drink by the vast number of Indian tribal people. In this study, the composition of microbial consortia and the occurrence of some important nutraceuticals during haria preparation were investigated. The quantities of moulds and yeasts were highest at 2nd day, and then declined, but, on the contrary, the quantity of Lactic Acid Bacteria and Bifidobacterium sp. increased concurrently during the course of fermentation. Accumulation of starch hydrolytic enzymes along with different types of malto-oligosaccharides like maltotetrose (26.18μg/gm), maltotriose (28.16μg/gm), and maltose (26.94μg/gm) were also noted. Furthermore, GC-MS analysis indicated the occurrence of pyranose derivatives in the fermented products. The fermented materials showed higher free radicals scavenging activity (82.54%, 4th day) against DPPH radicals. These studies clearly demonstrated that the microbial interaction during fermentation of rice makes it more nutritious, and most likely more beneficial for health.

Role of probiotic Lactobacillus fermentum KKL1 in the preparation of a rice based fermented beverage

A dominant lactic acid bacteria, Lactobacillus fermentum KKL1 was isolated from an Indian rice based fermented beverage and its fermentative behavior on rice was evaluated. The isolate grown well in rice and decreased the pH, with an increase of total titratable acidity on account of high yield in lactic acid and acetic acid. The production of α-amylase and glucoamylase by the strain reached plateau on 1st and 2nd day of fermentation respectively. The accumulation of malto-oligosaccharides of different degrees of polymerization was also found highest on 4th day. Besides, phytase activity along with accumulation of free minerals also unremittingly increased throughout the fermentation. The fermented materials showed free radical scavenging activity against DPPH radicals. In-vitro characteristics revealed the suitability of the isolate as probiotic organism. The above profiling revealed that probiotic L. fermentum KKL1 have the significant impact in preparation of rice beer and improves its functional characteristics.

Alteration of predominant gastrointestinal flora and oxidative damage of large intestine under simulated hypobaric hypoxia.

Hypobaric hypoxia is an immediate and crucial starting mechanism of acute mountain sickness included with some non-specific gastrointestinal (GI) complications. To study the effect of hypoxia on GI microflora and its upshot to this system, male albino rats were exposed to 55 kPa (air pressure ~ 4872.9 m altitude) consecutively 30 days for 8 hours/day. The different indicator group of large intestinal microbial populations were enumerated and correlated with the levels of antioxidant indicators like catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSG) of large intestinal epithelial cells. In addition, the histological study was performed by haematoxylin eosin (HE), periodic acid schiff staining (PAS) and scanning electron microscopy (SEM). It was observed that the density of total aerobes (104 folds) significantly (p < 0.05) decreased but the population of total anaerobes (209 folds) and Escherichia coli (125 folds) elevated after 30 days of hypoxic stress. The strict anaerobes like Bifidobacterium spp. (3 folds), Bacteroides spp. (134 folds), Lactobacillus spp. (7 folds) and other selected obligate anaerobes like Clostridium perfringens (40 folds), Peptostreptococcus spp. (21 folds) increased in respect to their control population. The growth direction index (GDI) of anaerobic populations was positive and correlated with gas formation aptitude. The activities of CAT and SOD in the large intestinal epithelia decreased significantly (p < 0.05) and GSH/GSSG pool turned into oxidized state with higher MDA (p < 0.05) formation. Histological study revealed the necrotized epithelial layer with higher lymphocytes infiltration in lamina propia accompanied by reduction of acidic mucins secreting goblet cells. From this experiment, it can be hypothesized that high altitude induced hypoxia manipulated the bacterial imprint and damaged the epithelial barrier of the large intestine which may cause systemic infection.

Thermodynamics and kinetic properties of halostable endoglucanase from Aspergillus fumigatus ABK9

An endoglucanase from Aspergillus fumigatus ABK9 was purified from the culture extract of solid‐state fermentation and its some characteristics were evaluated. The molecular weight of the purified enzyme (56.3 kDa) was determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, zymogram analysis and confirmed by MALDI‐TOF mass spectrometry. The enzyme was active optimally at 50 °C, pH 5.0 and stable over a broad range of pH (4.0–7.0) and NaCl concentration of 0–3.0 M. The pKa1 and pKa2 of the ionizable groups of the active sites were 2.94 and 6.53, respectively. The apparent Km, Vmax, and Kcat values for carboxymethyl cellulose were 6.7 mg ml−1, 775.4 µmol min−1, and 42.84 × 104 s−1, respectively. Thermostability of the enzyme was evidenced by the high activation energy (91.45 kJ mol−1), large enthalpy for activation of denaturation (88.77 kJ mol−1), longer half‐life (T1/2) (433 min at 50 °C), higher melting temperature (Tm) (73.5 °C), and Q10 (1.3) values. All the characteristics favors its suitability as halotolerant and thermostable enzyme during bioprocessing of lignocellulosic materials.

Variation of antioxidant biomarkers in the edible oyster Saccostrea cucullata collected from three different water bodies of Sundarbans

Variations of antioxidant biomarkers such as catalase (CAT), superoxide dismutase (SOD) activities and lipid peroxidation (LPO) were studied in edible part of mangrove oyster Saccostrea cucullata, collected from three different water bodies, such as Namkhana (S-I), Frazergaunge (S-II) and Sajnekhali (S-III) of Indian Sundarbans which are exposed to different degrees of anthropogenic activity. The study was conducted for consecutive two years (2010 and 2011) in the respective water bodies. Characteristics of biomarkers in oyster from the two polluted water bodies, i.e. S-I and S-II, are similar in nature in comparison to less polluted site (S-III). The catalase, superoxide dismutase activity and lipid peroxidation in oyster flesh exhibit significant (p<0.01) spatial and temporal variation among the three stations. Oysters from S-I were significantly higher (p<0.05) in antioxidant enzyme activities than oysters from S-III, which differ in their amount of pollution sources. Maximum antioxidant enzymes activity of all collected samples were recorded in pre-monsoon time and decreased in monsoon season. But maximum lipid peroxidation was noted during monsoon followed by post-monsoon and pre-monsoon.

Hypobaric-hypoxia Induces Alteration in Microbes and Microbes-associated Enzyme Profile in Rat Colonic Samples

Present study deals with the straight impact of hypobaric hypoxia on the quantity and composition of some predominant fecal microflora and its functional aspects. For that, isolated fecal contents of rat were exposed to two different simulated air pressures (70 kPa and 40 kPa) for different time durations (1, 3, and 5 h) and the bacterial community composition was compared with normobaric groups (101.3 kPa). It was found that the total anaerobes, Escherichia coli, Enterbacters spp., Bifidobacterium spp., Clostridium spp. were increased whereas total aerobes were decreased at both hypobaric treatments. The increased number of amplicon was detected in the pressure-treated groups than the control that clearly mentioned the disruption of microbiota structure at different simulated hypobaric-hypoxia. The amylase, protease, tannase, β-glucuronidase, and alkaline phosphatase activities were increased at these atmospheric pressures. Thus, the present investigation demonstrates that the hypobaric hypoxia is an important environmental factor which can strongly modulate the composition of intestinal flora as well as microflora-derived functional aspects.