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31.
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Siddhartha Kumar Bhaumik Manoj Kumar Singh Subir Karmakar Tripti De 《Glycoconjugate journal》2009,26(6):663-673
As compared to cutaneous leishmaniasis, vaccination against visceral leishmaniasis (VL) has received limited attention. In
this study, we demonstrate for the first time that an UDP-Galactose: N-acetylglucosamine β 1–4 galactosyltransferase (GenBank Accession No. EF159943) expressing attenuated LD clonal population (A-LD) is able to confer protection against the experimental challenge with the virulent LD AG83 parasite. A-LD was also effective in established leishmania infection. The vaccinated animals showed both cell mediated
(in vitro T-cell proliferation, and DTH response) and humoral responses (Th1 type). These results demonstrate the potential of the
attenuated clones as an immunotherapeutic and immunoprophylactic agent against visceral leishmaniasis. 相似文献
33.
M Singh 《Life sciences》1980,26(9):715-724
The present study was designed to determine the effect of vitamin B6 deficiency on pancreatic acinar cell function. Rats were either fed or rendered B6-deficient by a purified B6-deficient diet; half of the latter being replenished with IP pyridoxine before sacrifice. Body weight, pancreatic weight, RNA and DNA content were decreased in B6-deficient animals. These changes were considered to be due to inanition resulting from decreased food intake. Amylase content of pancreas in B6-deficient animals was less compared with B6-replenished animals. Although slightly higher in B6-deficient animals, the incorporation of L-phenylalanine14C into total tissue proteins was not significantly different in the three groups of animals. On B6-replenishment, incorporation of L-phenylalanine14C into nascent proteins was diminished in spite of higher tissue amylase and protein content. Vitamin B6 deficiency decreased total RNA content and adenine-8-14C incorporation into RNA. DNA content was diminished but incorporation of thymidine-2-14C into DNA was increased. On replenishment with B6, thymidine-2-14C incorporation decreased significantly compared to control animals. Secretion of amylase was diminished commensurate with decreased content. It is concluded from these studies that B6-deficiency induced DNA injury, decreased RNA turnover and increased protein turnover resulting in diminished amylase content. These data indicate that B6-deficiency so frequently encountered in alcoholism may contribute to the pancreatic injury in this clinical condition. 相似文献
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Experimental evidence suggests that proteins adsorbed to hydrophobic surfaces at low coverages are stabilized relative to the bulk. For larger coverages, proteins unfold and form β-sheets. We performed computer simulations on model proteins and found that: 1), For weakly adsorbing surfaces, unfolded conformations lose more entropy upon adsorption than folded ones. 2), The melting temperature, both in the bulk and at surfaces, decreases with increasing protein concentration because of favorable interprotein interactions. 3), Proteins in the bulk show large unfolding free energy barriers; this barrier decreases at stronger adsorbing surfaces. We conjecture that typical experimental temperatures appear to be below the bulk melting temperature for a single protein, but above the melting temperature for concentrated protein solutions. Purely thermodynamic factors then explain protein stabilization on adsorption at low concentrations. However, both thermodynamic and kinetic factors are important at higher concentrations. Thus, proteins in the bulk do not denature with increasing concentration due to large kinetic barriers, even though the aggregated state is thermodynamically preferred. However, they readily unfold upon adsorption, with the surface acting as a heterogeneous catalyst. The thermal behavior of proteins adsorbed to hydrophobic surfaces thus appears to follow behavior independent of their chemical specificity. 相似文献
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Eriocaulon raipurense (Eriocaulaceae) is described and illustrated as a new species from Madhya Pradesh, India. The species is closely allied to E. hamiltonianum but differs in the size and apex of involucral bancts, white-pilose nature of floral bracts and colour of female petals. 相似文献
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The nif gene group from Klebsiella can be transferred into Enterobacter cloacae by conjugation using Escherichia coli donor cells carrying the composite self-transmissible nif-plasmid pRD1. A small fraction of the hybrids obtained is stable upon prolonged passaging without selection. Their stability is due to integration of pRD1 into the chromosome. Such integration hybrids were chlorate resistant, and nitrate reductase negative, which indicated that integration preferentially occurred within one of the genes for the production or functioning of this enzyme. Chlorate resistance could, therefore, be used to select for additional nitrate reductase-negative sublines with pRD1 in their chromosome. Such sublines have been analyzed further for the presence of nif genes, other pRD1 markers, and for stability. In all except one the complete plasmid seems to have been integrated. Some tend to revert to nitrate utilisation (chlorate sensitivity). 相似文献