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91.
Ram S. Verma Carole Rubenstein Harvey Dosik 《In vitro cellular & developmental biology. Plant》1977,13(11):806-807
Summary There was no significant difference in the mitotic indices of the cultures maintained at different CO2 concentrations, i.e. 0%, 5% and 10%. However, considerable variation was recorded among different individuals.
Supported by National Cancer Institute Contract No. 1 CP 43251. 相似文献
92.
Antibodies directed toward human erythrocyte Ca2+-ATPase: effect on enzyme function and immunoreactivity of Ca2+-ATPases from other sources 总被引:3,自引:0,他引:3
Antibodies directed against purified human erythrocyte Ca2+-ATPase (purified according to a procedure modified from V. Niggli, J. T. Penniston, and E. Carafoli, 1979, J. Biol. Chem., 254, 9955–9958) were raised in rabbits. In competitive radioimmunoassay tests of immunological cross-reactivity, human erythrocyte Ca2+-ATPase shows a consistent pattern of immunological similarity to the Ca2+-ATPases derived from cell surface fractions of other species, such as rat and dog erythrocyte ghosts, rat corpus luteum plasma membranes, and rat brain synaptic plasma membranes. On the other hand, a purified Ca2+-ATPase preparation from rabbit skeletal muscle sarcoplasmic reticulum failed to show any immunological similarity to the human enzyme. The amount of Ca2+-ATPase protein in the erythrocyte ghosts was estimated to be about 0.6 μg/mg ghost protein, which was not too different from the calculated value of 1.2 ± 0.2 μg/mg ghost protein (mean ± SD, n = 6) based on the calmodulin binding studies of the erythrocyte ghosts. Anti-Ca2+-ATPase immunoglobulin G inhibited enzyme activity and calcium transport, showing that at least one subpopulation of antibodies can block the active site of the enzyme. The antibodies had no effect on the binding of calmodulin to erythrocyte membranes. 相似文献
93.
Chandra M. Dwivedi Laurence T. Plante Roy L. Kisliuk Edward J. Pastore Surendra P. Verma Donald F.H. Wallach 《Archives of biochemistry and biophysics》1982,213(1):338-340
Dihydrofolate reductase from Lactobacillus casei and its complexes with NADPH and methotrexate yield well-resolved Raman spectra. The 1685-cm?1 Raman band assigned to the carboxamide of NADPH persists in the NADPH-enzyme binary complex but is absent from the NADPH-methotrexate-enzyme ternary complex. This is ascribed to stabilization of the polarized form of the carboxamide by H bonding to the NH and CO groups of Ala 6 and Ile 13 of the peptide backbone. 相似文献
94.
The exopolysaccharide (EPS) of avirulentXanthomonas campestris pv.Malvacearum race-32 did not contain the watersoaking (WS)— inducing factor but contained necrotic reaction (NR)-inducing factor and induced
NR on resistant cotton (cv. 101-102B) on which the viable cells of the same avirulent race-32 produced hypersensitive reaction
(HR). NR and HR were differentiated on the basis of the induction period required, visible reaction on infiltrated areas,
bacterial constituents or metabolite responsible, involvement of host constituent during these reactions and its chemical
inhibition. Pre and/or challenge inoculation of EPS of avirulent race-32 (3 mg per infiltration or lesion) in susceptible
or resistant cotton cultivars, on pre-and/or post-infiltrated (0–8 h) exponential-phase culture of virulent race-32 inhibited
the WS and/or HR of the virulent race in susceptible or resistant cotton. 相似文献
95.
Photoreactivation of UV-irradiated DSNA with phr A photolyase from Escherichia coli was studied in the presence of yeast RNA. Mixing of RNA with UV-irradiated DNA before its treatment with photolyase inhibited the photoreactivation of DNA. Denatured (by sonication) RNA was found to be more effective in blocking photolyase action. Agarose gel electrophoresis experiments suggest that this inhibition of photoreactivation is due to interference in the binding of photolyase with UV-irradiated DNA by yeast RNA. 相似文献
96.
Effect of oestradiol was studied on the angiotensin converting enzyme (ACE)--a component of renin angiotensin system, in oviduct of immature quails of 15 days of age. ACE was studied in whole oviduct, magnum, shell gland and the glandular epithelium of magnum and shell gland. It was found that whole oviduct had a significantly higher level of ACE in control than those treated with exogenous estrogen at three dose levels (200, 400 or 600 micrograms). ACE contents of whole muscle and glandular epithelium did not differ but magnum had higher ACE level than the shell gland. Results are explained on the basis of functional role of oviductal parts. 相似文献
97.
K Marumo L Lindqvist N Verma A Weintraub P R Reeves A A Lindberg 《European journal of biochemistry》1992,204(2):539-545
A two-step enzymatic synthesis of dTDP-L-rhamnose is developed using enzymes from sonicated extracts of cultures of Escherichia coli K12 strains harboring plasmids containing different parts of the rfb gene cluster of Salmonella enterica LT2. The intermediate dTDP-6-deoxy-D-xylo-4-hexulose was isolated after a 1-h reaction, using only dTDP-D-glucose and dTDP-D-glucose 4,6-dehydratase, followed by protein precipitation and desalting by gel chromatography (yield 89%). In a two-step reaction using dTDP-D-glucose and dTDP-D-glucose 4,6-dehydratase in the first step, and with NADPH, dTDP-6-deoxy-D-xylo-4-hexulose 3,5-epimerase and NADPH:dTDP-6-deoxy-L-lyxo-4-hexulose-4-reductase in the second hour of incubation, the dTDP-D-glucose was fully converted to dTDP-L-rhamnose. The hexoses of both products were identified by mass spectroscopy. The molar yield of dTDP-L-rhamnose, after protein precipitation, anion-exchange chromatography and desalting by gel chromatography, was 62%, corresponding to more than 150 mg, starting from 250 mg of dTDP-D-glucose. When stored lyophilysed under nitrogen, these products were found to be stable for several months. Both dTDP-6-deoxy-D-xylo-4-hexulose and dTDP-L-rhamnose have light absorption maxima at 267 nm, with molar absorption coefficients close to that of dTMP. However, the absorption coefficient of dTDP-6-deoxy-D-xylo-4-hexulose at the absorption maximum of 320 nm (specific for sugars containing keto groups) was found to be approximately 20% higher than values presented earlier. Furthermore, an HPLC technique is presented for determining the net activity of dTDP-6-deoxy-D-xylo-4-hexulose 3,5-epimerase and NADPH:dTDP-6-deoxy-L-lyxo-4-hexulose-4-reductase, based on separation of dTDP-6-deoxy-D-xylo-4-hexulose and dTDP-L-rhamnose. The HPLC technique is also suitable for determination of all the nucleotide components involved in the synthesis. 相似文献
98.
The symbiotic root nodule, an organ formed on leguminous plants, is a product of successful interactions between the host plant and the soil bacteria, Rhizobium spp. Plant hormones play an important role in the genesis of this organ. The hormonal balance appears to be modulated by the signals produced by bacteria. Many host genes induced during nodule organogenesis and the symbiotic state have been identified and characterized from several legumes. These genes encode nodule-specific proteins (nodulins) which perform diverse functions in root nodule development and metabolism. Formation of a subcellular compartment housing the bacteria is essential to sustain the symbiotic state, and several nodulins are involved in maintaining the integrity and function of this compartment. The bacteroid enclosed in the perbacteroid membrane behaves as an 'organelle,'completely dependent on the host for all its requirements for carbon, nitrogen and other essential elements. Thus it seems likely that the nodulins in the peribacteroid membrane perform specific transport functions. While the function of a few other nodulins is known (e.g. nodulin-100, nodulin-35), a group of uncharacterized nodulins exists in soybean root nodules. These nodulins share structural similarities and seem to have been derived from a common ancestor. Induction of nodulin genes occurs prior to and independent of nitrogen fixation, and thus is a prelude to symbiosis. Although some of the early nodulin genes are induced prior to or during infection, induction of late nodulins requires endocytotic release of bacteria. 相似文献
99.
1. Effects of endosulfan, malathion and carbaryl on circulating T4, T3 and T3/T4 ratio in the freshwater catfish, C. batrachus have been studied during reproductively active phases, i.e. vitellogenic and post-vitellogenic phases of its annual reproductive cycle. 2. Endosulfan provoked a significant increase in T4 and a decrease in T3 as well as the T3/T4 ratio. 3. Malathion decreased T3 and T3/T4 ratio without altering the level of T4 in circulation. 4. Carbaryl caused a decline in the level of T4 and an elevation in T3 and T3/T4 ratio. 相似文献
100.
In vitro absorption of nutrients like glucose, leucine, protein hydrolysate and Ca2+ by ligated loops of small intestine was significantly affected in presence of lectins from peas and lentils. Except for sucrose, all other nutrients showed significant decrease in their absorption in presence of lectins. Lentil lectins had a greater inhibitory effect than pea lectins. 相似文献