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21.
Frankia is the diverse bacterial genus that fixes nitrogen within root nodules of actinorhizal trees and shrubs. Systematic and ecological studies of Frankia have been hindered by the lack of morphological, biochemical, or other markers to readily distinguish strains. Recently, nucleotide sequence of 16 S RNA from the small ribosomal subunit has been used to classify and identify a variety of microorganisms. We report nucleotide sequences from portions of the 16 S ribosomal RNA from Frankia strains AcnI1 isolated from Alnus viridis ssp. crispa (Ait.) Turrill and PtI1 isolated from Purshia tridentata (Pursh) DC. The number of nucleotide base substitutions and gaps we find more than doubles the previously reported sequence diversity for the same variable regions within other strains of Frankia.  相似文献   
22.
For estimation of growth, the efficiency of linked cross sectional scheme has been compared with pure longitudinal and cross sectional schemes. The relevant estimation theory has been developed and the expressions for the optimum estimators alongwith their variances have been derived. It has been observed that for estimation of growth, the linked cross-sectional scheme has been observed to be less efficient as compared to pure longitudinal scheme but more efficient than pure cross-sectional scheme.  相似文献   
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QSAR studies have been performed on the homologues of 3-triazines, using molecular connectivity index and van der Waal volume as structural parameters. The regression analysis has shown good correlation between antitumour activity and the two structural parameters.  相似文献   
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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   
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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 adlib 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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