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A study was conducted to investigate the parasitic diversity prevailing in the natural population of common crow, Corvus splendens from an urban habitat of Kolkata, India. A population of twenty birds were examined for ectoparasites, endoparasites, essential blood parameters and selected histopathological study. The blood samples from two male and two female birds were found to be infected with Plasmodium sp. and the histopathology of the liver of the infected birds exhibited signs of inflammation. Six species of chewing lice were identified from the feathers of the birds. Deformities and developmental anomalies in a significantly large number of the examined lice population were observed. The birds infected with Plasmodium sp. expressed no notable sign of being diseased with respect to the uninfected birds and observed blood parameters like haemoglobin content, total count of red blood corpuscles, serum calcium, magnesium, albumin and glucose did not differ significantly across sexes. The presence of deformed lice in the feathers of the birds probably indicates the host's unique defence strategy against the ectoparasites although the observation demands further study. As a whole, C. splendens thus emerges as a challenging model for exploration of the host-parasite dynamics. [ABSTRACT FROM AUTHOR]

The present investigation was carried out to underscore the developmental events of a crustacean ectoparasite of fish, Argulus bengalensis. Serial histological sections of the embryo were made at lateral, sagittal and longitudinal planes to explain its cleavage, gastrulation and axis specification. The centrolecithal egg of A. bengalensis underwent meroblastic superficial cleavage. The cleavage initiated at the future dorsal side of the egg within 5 h to 5 h and 30 min of incubation. Consequently, a small mass of energids appeared superficially at the future dorsal side within 6 h. Later, energids were found at the future ventral and lateral sides. A syncytial blastoderm was formed around the centrally placed yolk material which was transformed into a cellular blastoderm within 30 h of incubation. In the blastoderm, two cell masses were formed at the dorsal and ventral part which initially extended towards each other and later spread out though future anterior-posterior direction. The pressure exerted by the cell flow displaced the entire yolk material at the future postero-ventral side. At the time of egg laying, a prototype of the embryonic axes is determined. The substratum side of the egg formed the dorsal part, whilst the side facing water turned to the ventral part. The broader end of the egg formed the anterior side and the narrow end formed the posterior side of the embryo. The anterior-posterior axis formation was initiated within 72 to 96 h of incubation when the blastodermal cells displaced the yolk material at the future posterior end. Within 120 h of incubation, the germ layers of the embryo were determined. The study reveals that the cleavage pattern of A. bengalensis shows close similarities with that of the Malacostraca amongst the crustaceans and dipteran and hymenopteran amongst the insects. [ABSTRACT FROM AUTHOR]

The production of amylolytic enzymes by a thermophilic cellulolytic fungus, Myceliophthora thermophila D14 was investigated by batch cultivation in Czapek-Dox medium at 45° C. Among various nitrogenous compounds used, NaNO and KNO were found to be the best for amylase production. Starch, cellobiose and maltose induced the synthesis of amylase while glucose, fructose, galactose, lactose, arabinose, xylose, sorbitol, mesoinositol and sucrose did not. Calcium ions had the most stimulating effect on enzyme formation amongst many ions investigated. The synthesis of amylolytic enzymes was dependent on growth and occurred predominantly in the mid-stationary phase. The enzyme was active in a broad temperature range (50° C-60° C) and displayed activity optima at 60° C and pH 5.6. [ABSTRACT FROM AUTHOR]

An l-asparaginase produced by Pseudomonas stutzeri MB-405 was isolated and characterized. After initial ammonium sulfate fractionation, the enzyme was purified by consecutive column chromatography on Sephadex G-100, Ca-hydroxylapatite, and DEAE-Sephadex A-50. The 665.5-fold purified enzyme thus obtained has the specific activity of 732.3 units mg protein with an overall recovery of 27.2%. The apparent M of the enzyme under nondenaturing and denaturing conditions was 34 kDa and 33 kDa respectively, and the isoelectric point was 6.38±0.02. It displayed optimum activity at pH 9.0 and 37°C. The enzyme was very specific for l-asparagine and did not hydrolyze L-glutaminate. The K of the l-asparaginase was found to be 1.45×10 m towards l-asparagine and was competitively inhibited by 5-diazo-4-oxo- l-norvaline (DONV) with a K of 0.03 mm. Metal ions such as Mn, Zn, Hg, Fe, Ni, and Cd potentially inhibited the enzyme activity. The activity was enhanced in the presence of thiol-protecting reagents such as DTT, 2-ME, and glutathione (reduced), but inhibited by PCMB and iodoacetamide. The tumor inhibition study with Dalton's lymphoma tumor cells in vivo indicated that this enzyme possesses antitumor properties. [ABSTRACT FROM AUTHOR]