Antioxidant and neuroprotective potential of chitooligomers in Caenorhabditis elegans exposed to Monocrotophos.

The objectives of this investigation were to establish the propensity of the chitooligomers (COS) to ameliorate neurodegeneration and oxidative stress in Caenorhabditis elegans induced by an organophosphorus insecticide, Monocrotophos (MCP). COS was prepared from α-chitosan by the enzymatic method using chitosanase and characterized by HPLC and electron spray ionization-TOF-(ESI-TOF)-MS. We exposed age synchronized L4 C. elegans worms (both wild type N2 and transgenic strain BZ555 (Pdat-1:GFP) to sublethal concentration of MCP (0.75mM) for 24h in the presence or absence of COS (0.2mM). The neuroprotective effect of COS was examined in N2 worms in terms of brood size, lifespan, egg laying, dopamine content, acetylcholinesterase and carboxylesterase activity and by direct visualization and quantification of degeneration of dopaminergic neurons in BZ555. Exposure to COS extended lifespan, normalized egg laying, increased brood size, decreased the dopaminergic neurodegeneration, increased the dopamine content and increased AChE and carboxylesterase activity in C. elegans treated with MCP. COS induced a significant decrease in reactive oxygen species and increased the reduced glutathione level as well as increased superoxide dismutase and catalase activity. Our findings demonstrate that COS significantly inhibits the dopaminergic neurodegeneration and associated physiological alterations induced by MCP in C. elegans by attenuating the oxidative stress as well.

Application of chitosan for improvement of quality and shelf life of table eggs under tropical room conditions.

The current investigation was conducted to study the effectiveness of chitosan coating in preserving the internal quality of table eggs stored under tropical room conditions of 32 ± 1 °C and 60-70 % r. h. Internal, physical and microbiological quality of eggs coated with chitosan was evaluated during 5-week storage at different temperature (22 ± 1 and 32 ± 1 °C). Chitin was extracted from shrimp processing raw byproducts and deacetylated to high quality chitosan. The prepared chitosan was analyzed for its characteristic properties. The chitosan with a viscosity of 2206 mPa.S was used to prepare the coating solution. The weight loss, Haugh unit, and yolk index values suggested that coating of eggs with shrimp α-chitosan increased the shelf life of eggs by almost 4-week at 22 ± 1 °C and 3-week at 32 ± 1 °C compared with controls (non chitosan coated and acetic acid coated) eggs. Three-time repeated coating was more effective in preserving the internal quality and preventing weight loss than with single-time coating of chitosan on egg. Therefore, three-time coating of eggs with 2206 mPa.S chitosan offer a protective barrier for preserving the internal quality of eggs stored at tropical room conditions and concomitantly prevent contamination with microorganisms.

Optimization of conditions for isolation of high quality chitin from shrimp processing raw byproducts using response surface methodology and its characterization.

Chitin is one of the most abundant bioactive biopolymer on earth. It is commercially extracted from seafood processing crustacean shell byproducts by harsh thermochemical treatments. The extraction conditions, the source and pretreatment of raw material significantly affect its quality and bioactivity. In this investigation response surface methodology (RSM) has been applied to optimize and evaluate the interaction of variables for extraction of high quality chitin from shrimp processing raw byproducts. Variables such as, concentration of HCl (%, v/v) 4.5 (for wet) and 4.9 (for dry), reaction time 3 h, solid liquid ratio of HCl (w/v) 1:5.5 (for wet) and 1:7.9 (for dry) with two treatments achieved >98 % demineralization of shrimp byproduct. Variables such as, concentration of NaOH 3.6 % (w/v), reaction time 2.5 h, temperature 69.0 ± 1 °C, solid liquid ratio of NaOH 7.4 (w/v) and two treatments accomplished >98 % deproteinization of demineralized byproducts. Significant (p ≤ 0.05-0.001) interactive effects were observed between different variables. Chitin obtained in these conditions had residual content (%, w/w) of ash <0.4 and protein <0.8 and the degree of N-acetylation was >93 % with purity of >98 %. In conclusion, the optimized conditions by RSM can be applied for large scale preparation of high quality chitin from raw shrimp byproduct.

Chitooligomers preparation by chitosanase produced under solid state fermentation using shrimp by-products as substrate.

Solid state fermentation (SSF) conditions were statistically optimized for the production of chitosanase by Purpureocillium lilacinum CFRNT12 using shrimp by-products as substrate. Central composite design and response surface methodology were applied to evaluate the effect of variables and their optimization. Incubation temperature, incubation time, concentration of inoculum and yeast extract were found to influence the chitosanase production significantly. The R(2) value of 0.94 indicates the aptness of the model. The level of variables for optimal production of chitosanase was 32 ± 1°C temperature, 96 h incubation, 10.5% (w/v) inoculum, 1.05% (w/w) yeast extract and 65% (w/w) moisture content. The chitosanase production was found to increase from 2.34 ± 0.07 to 41.78 ± 0.73 units/g initial dry substrate after optimization. The crude chitosanase produced 4.43 mM of chitooligomers as exclusive end product from colloidal chitosan hydrolysis. These results indicate the potential of P. lilacinum CFRNT12 for the chitosanase production employing cost effective SSF using shrimp by-products.

Comparative study on characteristics and in vitro fibril formation ability of acid and pepsin soluble collagen from the skin of catla (Catla catla) and rohu (Labeo rohita).

Catla (Catla catla) and Rohu (Labeo rohita) are the major carp fish produced by freshwater aquaculture in India. Processing of these carp fish generates potentially large quantities of by-products (waste) from non-edible fish parts by fish-processing factories and fish shops. The paper focuses on the extraction of the acid soluble collagen (ASC) and pepsin soluble collagen (PSC) from the skin of carp fish and subsequently their characteristics and in vitro fibril-forming ability. The extracted collagens are characterized as type I collagen based on the electrophoretic pattern. The denaturation temperature for all the collagens extracted was found to be 30.69-35.19°C by differential scanning calorimetry (DSC) analysis. The extracted collagens exhibited higher solubility at low concentration of NaCl (0-0.4M). All the ASC and PSC displayed different degrees of fibril-forming abilities and the scanning electron microscopy (SEM) analysis confirmed their well-defined fibril morphologies. The degree of collagen fibril formation was significantly (p≤0.05) higher (78%) in rohu skin collagen than catla skin collagen (36%). In general, the characteristics of two carp skin collagens were unique as evidenced by the electrophoretic, DSC, SEM and fibril-forming patterns. Overall, the results indicated the feasibility of using the carp skin as a good alternative source of realistic high-quality collagen.