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1.
Inhibition of protein and lipid synthesis in muscle by 2,4-dinitrofluorobenzene, an inhibitor of creatine phosphokinase 总被引:2,自引:0,他引:2
C L Carpenter C Mohan S P Bessman 《Biochemical and biophysical research communications》1983,111(3):884-889
A photoaffinity label, 4-azidobenzoyltrimethionine has been synthesized. It competitively inhibits trimethionine uptake in the yeast C. albicans. Upon UV irradiation it irreversibly and specifically blocks oligopeptide uptake. These results give the first example of photoinhibition of peptide uptake in yeast. 相似文献
2.
3.
Role of Thidiazuron (TDZ) in inducing adventitious organogenesis in Pongamia was studied. TDZ at different concentrations (0, 0.45, 2.27, 4.54, 6.71, 9.08, 11.35, 13.12 and 22.71 μM) were used for induction
of caulogenic bud formation in deembryonated cotyledon explants. Each cotyledon was cut into three segments and identified
as proximal, middle and distal. Duration of TDZ exposure, influence of the segment and orientation of the explant were studied.
TDZ at 11.35 μM concentration was optimum for the induction of shoots and rapid elongation. Shoots induced at higher concentration
elongated after several passages in growth regulator free medium, thereby extending the period of differentiation. Exposure
of the explant for 20 days yielded more number of buds than 10 days. Proximal segment of the cotyledon was more responsive.
Contact of abaxial surface in the medium was more effective and generated more buds than the adaxial side. Buds differentiated
and elongated on transfer to MS basal medium for 8–12 passages of 15 days each. Rooting and elongation of shoots was achieved
in charcoal supplemented half-strength MS medium. Rooted plantlets survived on transfer to sand soil mixture. The plants were
hardened and transferred to green house. This is the first report on in vitro regeneration of Pongamia pinnata via adventitious organogenesis using TDZ. This protocol may find application in studies in genetic transformation, isolation
of somaclonal variants and in induction of mutants. It also provides a system to study the inhibitory role of TDZ on shoot
differentiation. 相似文献
4.
Effect of chemical modification on the binding of gossypol by gossypin (11S protein) and congossypin (7S protein) of cottonseed 总被引:1,自引:0,他引:1
Binding of gossypol by gossypin and congossypin and their succinylated and sulfhydryl group-blocked derivatives has been measured.
The binding by gossypin and congossypin is characterized by weak interaction. Succinylation of gossypin decreases the binding
affinity whereas that of congossypin increases it. Blocking of sulfhydryl groups of both the proteins does not significantly
affect gossypol binding, Succinylation dissociates gossypin and causes conformational changes whereas it does not dissociate
congossypin but causes conformational changes. Sulfhydryl group blocking does not dissociate gossypin or congossypin, nor
does it cause any conformational changes. 相似文献
5.
The response ofCicer arietinum to inoculation withGlomus versiforme under field conditions was investigated in a phosphorus deficient sandy loam soil. Inoculation with the mycorrhizal fungusGlomus versiforme increased the rate of VAM development in chickpea. The weight of nodules and the number of nodules per plant were higher
in inoculated than in uninoculated plants. The phosphorus content of the shoots and its total uptake, were increased by either
the application of single super-phosphate, or by inoculation withG. versiforme. Inoculation increased shoot dry weights and grain yields by 12% and 25% respectively, as compared with the 33% and 60% increases
respectively produced by P-treated plants. 相似文献
6.
Characterization and differential expression of human vascular smooth muscle myosin light chain 2 isoform in nonmuscle cells 总被引:6,自引:0,他引:6
The 20-kDa regulatory myosin light chain (MLC), also known as MLC-2, plays an important role in the regulation of both smooth muscle and nonmuscle cell contractile activity. Phosphorylation of MLC-2 by the enzyme MLC kinase increases the actin-activated myosin ATPase activity and thereby regulates the contractile activity. We have isolated and characterized an MLC-2 cDNA corresponding to the human vascular smooth muscle MLC-2 isoform from a cDNA library derived from umbilical artery RNA. The translation of the in vitro synthesized mRNA, corresponding to the cDNA insert, in a rabbit reticulocyte lysate results in the synthesis of a 20,000-dalton protein that is immunoreactive with antibodies raised against purified chicken gizzard MLC-2. The derived amino acid sequence of the putative human smooth muscle MLC-2 shows only three amino acid differences when compared to chicken gizzard MLC-2. However, comparison with the human cardiac isoform reveals only 48% homology. Blot hybridizations and S1 nuclease analysis indicate that the human smooth muscle MLC-2 isoform is expressed restrictively in smooth muscle tissues such as colon and uterus and in some, but not all, nonmuscle cell lines. Previously reported MLC-2 cDNA from rat aortic smooth muscle cells in culture is ubiquitously expressed in all muscle and nonmuscle cells, and it was suggested that both smooth muscle and nonmuscle MLC-2 proteins are identical and are probably encoded by the same gene. In contrast, the human smooth muscle MLC-2 cDNA that we have characterized from an intact smooth muscle tissue is not expressed in skeletal and cardiac muscles and also in a number of nonmuscle cells.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
Inhibitory insulin-like growth factor-binding protein: cloning, complete sequence, and physiological regulation. 总被引:5,自引:0,他引:5
D LaTour S Mohan T A Linkhart D J Baylink D D Strong 《Molecular endocrinology (Baltimore, Md.)》1990,4(12):1806-1814
In this study we report the preparation of a human osteosarcoma cell cDNA library and describe the isolation and sequence determination of a clone encoding the complete sequence of a novel human insulin-like growth factor (IGF)-binding protein (hIGFBP-4). Previous work indicated that hIGFBP-4 is the predominant IGFBP expressed by human osteoblast-like cells, and that IGFBP-4 binds and inhibits the mitogenic activities of IGF-I and IGF-II. Sequence determination revealed that hIGFBP-4 is a unique gene product with significant amino- and carboxy-terminal sequence similarity to three other known IGFBPs. Identical alignment of 18 cysteines in IGFBP-4 and the three other IGFBPs is a key structural feature of this protein family. In vitro studies of human osteoblast-like cells suggest that PTH regulates the expression of hIGFBP-4 and that the PTH effect is mediated through a cAMP mechanism. hIGFBP-4 mRNA was also expressed in skin fibroblasts, and thus, this inhibitory IGFBP could be an important physiological regulator of IGF actions in bone cells and other cell types as well. 相似文献
8.
The effect of subzero temperatures on the electrophoretic pattern of seminal plasma protein of cattle and buffalo was studied. The profiles of the seminal proteins of these two closely related species differed considerably. Cattle had 11 proteins in the anodic system (pH 8.6) and none in the cathodic system (pH 4.3), while buffalo have 19 in the anodic system (pH 8.6) and 2 proteins in the cathodic system (pH 4.3). Freezing of semen at -5 degrees C for 24 h caused aggregation of seminal proteins in both species. A higher aggregation and loss of proteins were observed when freezing was done in liquid nitrogen at -196 degrees C. The effect was more pronounced in buffalo than in cattle. Loss of more seminal plasma proteins due to cryoinjury in buffalo semen may account for its poorer freezability than that of cattle semen. 相似文献
9.
We have cloned and characterized a 55-kb region of DNA surrounding HRAS1. It contains a cluster of two, and possibly three, genes associated with CpG islands within the 32 kb immediately upstream of HRAS1. We have sequenced cDNAs representing one of these genes, provisionally designated HRC1. The locus, which is located 29 kb upstream of HRAS1, is divergently transcribed. HRC1 cDNA probe recognizes fragments on Southern blots of DNA from other vertebrate species. In human DNA, multiple homologous fragments are detected in addition to the predicted ones containing HRC1. Therefore, this locus may represent a member of an evolutionarily conserved gene family. HRC1 expression is upregulated with HRAS1 in the EJ bladder carcinoma cell line, suggesting the possibility of coordinate regulation. The deduced translational product of the longest open reading frame (1119 nucleotides, 373 amino acids) predicts a protein with regions rich in glutamine and proline and a region similar to the helix-loop-helix motif adjacent to a carboxy-terminal leucine zipper dimerization motif with four heptad repeats. Alternate splicing of terminal exons occurs, resulting in the truncation of one proline-rich domain and preservation of the leucine zipper. Thus, a biologically important region of chromosome 11p consists of a gene cluster. At least one of these genes, in addition to HRAS1, may be involved in regulation of cell growth or differentiation. 相似文献
10.
Scott Pownall Christine A. Kozak Keith Schappert Mohan Sarkar Eric Hull Harry Schachter Jamey D. Marth 《Genomics》1992,12(4)
The biosynthesis of protein-bound complex N-glycans in mammals requires a series of covalent modifications governed by a large number of specific glycosyltransferases and glycosidases. The addition of oligosaccharide to an asparagine residue on a nascent polypeptide chain begins in the endoplasmic reticulum. Oligosaccharide processing continues in the Golgi apparatus to produce a diversity of glycan structures. UDP-N-acetylglucosamine:α-3-
-mannoside β-1,2-N-acetylglucosaminyltransferase I (EC 2.4.1.101; GlcNAc-TI) is a key enzyme in the process because it is essential for the conversion of high-mannose N-glycans to complex and hybrid N-glycans. We have isolated the mouse gene encoding GlcNAc-TI (Mgat-1) from a genomic DNA library. The mouse sequence is highly conserved with respect to the human and rabbit homologs and exists as a single protein-encoding exon. Mgat-1 was mapped to mouse Chromosome 11, closely linked to the gene encoding interleukin-3 by the analysis of multilocus interspecies backcrosses. RNA analyses of Mgat-1 expression levels revealed significant variation among normal tissues and cells. 相似文献