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691.
During uridine starvation inEscherichia coli K12, the rate of RNA accumulation comes down to about 7% of the nonstarved rate. This is achieved, in part, by an eight-fold increase in the assembly time of stable RNA molecules. However, the assembly time of mRNA molecules is not enhanced as much, being longer by a factor of 3 in starved cells compared to nonstarved ones. It, therefore, appears that the rate of synthesis of these two RNA species is noncoordinately controlled during uridine starvation. This control does not seem to be mediated by guanosine tetraphosphate. 相似文献
692.
Circular dichroism studies of helical oligopeptides. Can 3(10) and alpha-helical conformations be chiroptically distinguished? 总被引:2,自引:0,他引:2
T S Sudha E K Vijayakumar P Balaram 《International journal of peptide and protein research》1983,22(4):464-468
Circular dichroism studies of seven helical oligopeptides containing alpha-aminoisobutyric acid (Aib) in methanol and trifluoroethanol (TFE) solutions are reported. Peptides ranging from 10 to 21 residues in length have been examined. In all cases distinct negative CD bands characteristic of helical peptides are obtained at approximately 220 and 205 nm corresponding to the n-pi and pi-pi transitions, respectively. The ratio R = [theta] pi-pi is less than 1.0 for all peptides studied. Using crystal structure and n.m.r. results for a 10 residue 3(10) helical peptide and literature values for an alpha-helical 11-residue peptide, it is shown that both helical conformations yield R values of approximately 0.8 in alcoholic solvents. The CD data are considered in the light of 1H n.m.r. studies on these oligopeptides. The results suggest that 3(10) and alpha-helical conformations cannot be distinguished by CD methods. 相似文献
693.
Translocation (14;21)(q11;q22) in a woman with history of abortions and a child with Down's syndrome
A translocation (14;21)(q11;q22) was observed in a woman with history of abortions and in her child with Down's syndrome. This appears to be the first report of such a translocation with no centric fusion between the acrocentric chromosomes leading to a count of 45 chromosomes in the carrier and giving birth to a Down's syndrome child. 相似文献
694.
Pragya Srivastava Rajneesh Jha Sylvette Bas Sudha Salhan Aruna Mittal 《Reproductive biology and endocrinology : RB&E》2008,6(1):20
Background
The magnitude of reproductive morbidity associated with sexually transmitted Chlamydia trachomatis infection is enormous. Association of antibodies to chlamydial heat shock proteins (cHSP) 60 and 10 with various disease sequelae such as infertility or ectopic pregnancy has been reported. Cell-mediated immunity is essential in resolution and in protection to Chlamydia as well as is involved in the immunopathogenesis of chlamydial diseases. To date only peripheral cell mediated immune responses have been evaluated for cHSP60. These studies suggest cHSPs as important factors involved in immunopathological condition associated with infection. Hence study of specific cytokine responses of mononuclear cells from the infectious site to cHSP60 and cHSP10 may elucidate their actual role in the cause of immunopathogenesis and the disease outcome. 相似文献695.
696.
697.
Srinivasan Bharathkumar N. RameshKumar Diby Paul V. R. Prabavathy Sudha Nair 《World journal of microbiology & biotechnology》2008,24(3):387-394
Variations in chemical parameters and bacterial populations in mangrove rhizosphere samples were noted for different sites.
The C, N, P and K contents as well as pH, EC and salinity showed variation between sites. Significant differences in soil
properties were also found in sampling sites. Two types of soil were noted among sites. Guesthouse had significantly higher
organic matter and nutrient content (N) than other three sites suggesting that human discharges, litter deposition and surface
runoff were major nutrient inputs. This contaminated site was located at the landward edges. Positive correlations between
organic matter, N, P and K contents were found suggesting that these nutrients were from similar input sources. Effects of
sampling sites on microbial diversity were also analyzed via SSCP. Porteresia coarctata and Rhizophora mucronata did not show any variation in the banding patterns among replicates sampled in short distance within site. But Sonneratia apetala showed variation among replicates sampled in distance within site. A significant variation was noted in the SSCP profile
among replicates between sites. The majority of dominant SSCP band sequences were related to bacterial genera of root and
root-free soil environments, namely Bacillus, Planococcus, Planomicrobium, low G+C Gram-positive bacterium, glacial ice bacterium and unidentified bacteria. In the analysis of 16S rRNA sequences,
members belonging to the phylum Firmicutes dominated the sequence collection. The phylogenetic analysis of 16S rRNA gene sequences showed close relationships to a wide range of clones or bacterial species of phylum Firmicutes and unidentified bacteria. 相似文献
698.
Junaid ur Rahim Arfan Khalid Sudha Shankar Irfan Qasam Govind Yadav Rajkishor Rai 《Journal of peptide science》2023,29(7):e3485
The present work describes the synthesis, characterization, and wound healing properties of α/γ hybrid peptides: Boc-Phe-γ4-Phe-Val-OMe ( S1 ), Boc-DPhe-γ4-Phe-Val-OMe ( S2 ), Boc-Ala-γ4-Phe-Val-OMe ( S3 ), Boc-DAla-γ4-Phe-Val-OMe ( S4 ), Boc-Leu-γ4-Phe-Val-OMe ( S5 ), and Boc-DLeu-γ4-Phe-Val-OMe ( S6 ). Peptides S1–S6 were screened against human keratinocytes (HaCaT) and RAW 264.7 cells. Among all, S1 - and S2 -treated cells exhibited high cell viability; S1 and S2 induced keratinocyte migration and inhibited the production of the cytokines IL-6 and TNF-α. In vivo results demonstrated that the hybrid peptides S1 and S2 accelerate wound healing in Wistar rats with 83% and 88% at 50 μg/ml, and 74% and 76% at 25 μg/ml, respectively. 相似文献
699.
Thebgl operon ofEscherichia coli, which encodes the genes necessary for transport and catabolism of β-glucosides, is silent in wild-type cells and is activated
by the transposition of IS elements. The silent form of the operon appears to be the stable state. We isolated Bgl- revertants of an activated strain after growth under nonselective conditions to understand whether activation of the cryptic
operon by IS elements is reversible. Genetic and molecular analyses revealed that a majority of revertants carry deletions
of thebgl structural genes, indicating that an irreversible alteration has occurred in the operon. Implications of these results for
the evolution and maintenance of cryptic genes are discussed. [Yakkundi A., Moorthy S. and Mahadevan S. 1998 Reversion of
anE. coli strain carrying an IS1-activatedbgl operon under nonselective conditions is predominantly due to deletions within the structural genes.J. Genet.
77, 21–26] 相似文献