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21.
Glutamine release from hindlimb and uptake by kidney in the acutely acidotic rat. 总被引:5,自引:3,他引:2
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The arteriovenous difference (release) for glutamine across the hindlimb increases significantly during acute HCl-induced acidosis. This additional amount release by muscle tissue can account for the extra glutamine taken up by the kidney. 相似文献
22.
An agar-diffusion method for determination of oleandomycin and tetracycline low levels in solutions of the drug combination was developed. The medhod may be used for investigation of oletetrin absorption and distribution in humans and animals. It provides high accuracy in separate determination of oleandomycin and tetracycline activity in solutions of the drugs at a ratio of 1 : 2. The same test-culture, Bac. subtilis, variant L2 is used for the assay of tetracycline and oleandomycin activity. The only differences are in the values of pH and the buffer solution and the standards. 相似文献
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24.
Summary A simple experimental method is devised to determine the fraction of plasmid-harboring cells in a bioprocess employing recombinant mammalian cells. The fraction of plasmid-harboring cells decreased as serum content in the growth medium decreased. The relatively higher increase in the generation time of the plasmid-harboring cell was primarily responsible for this decrease. The mathematical expression obtained for this fraction in terms of the two parameters, i.e. the generation time ratio and the plasmid-loss probability, could represent the experimental data extremely well. The numerical values of these parameters could show the inherent insight of the system. It was found that the data plot against time can draw us to a misleading conclusion of the absence of the effect of serum concentration. 相似文献
25.
Summary The cloning of glucoamylase geneSTA using theSUC2 promoter intoSaccharomyces cerevisiae was performed. The signal sequence ofSTA gene was used for the secretion of glucoamylase protein. The plasmid constructed in this way was named YEpSUCSTA and its expression was identified. The expression of YEpSUCSTA was repressed in the presence of glucose in growth medium, but derepressed when glucose became depleted. YEpSUCSTA showed the similar efficiency of glucoamylase secretion as YEpSTA-F which has the entireSTA gene. Glucoamylase activity in starch-glucose medium was largely increased because cell mass and plasmid stability were high in biosynthesis phase compared to extracellular glucoamylase activities in media which starch or glucose was the only carbon source. 相似文献
26.
We have demonstrated previously that the template sequences 5'-GTT-3' and 5'-GCT-3' serve as necessary and sufficient signals for the initiation of new DNA chains that start with pentaribonucleotide primers of sequence pppApCpNpNpN or pppGpCpNpNpN, respectively. Normally, the complete T4 primosome, consisting of the T4 gene 41 (DNA helicase) and gene 61 (primase) proteins, is required to produce RNA primers. However, a high concentration of the 61 protein alone can prime DNA chain starts from the GCT sites [Cha, T.-A., & Alberts, B. M. (1986) J. Biol. Chem. 261, 7001-7010]. We show here that the 61 protein can catalyze a single-stranded DNA template-dependent reaction in which the dimers pppApC and pppGpC are the major products and much longer oligomers of various lengths are minor ones. Further addition of the 41 protein is needed to form a primosome that catalyzes efficient synthesis of the physiologically relevant pentaribonucleotides that are responsible for the de novo DNA chain starts on the lagging strand of a replication fork. The helicase activity of the 41 protein is necessary and sufficient to ensure a high rate and processivity of DNA synthesis on the leading strand [Cha, T.-A., & Alberts, B. M. (1989) J. Biol. Chem. 264, 12220-12225]. Coupling an RNA primase to this helicase in the primosome therefore coordinates the leading- and lagging-strand DNA syntheses at a DNA replication fork. Our experiments reveal that the addition of the T4 helix-destabilizing protein (the gene 32 protein) is required to confine the synthesis of RNA primers to those sites where they are used to start an Okazaki fragment, causing many potential priming sites to be passed by the primosome without triggering primer synthesis. 相似文献
27.
A biological method was used in addition to the chemical methods of identification in the screening programme of new antibiotics. The method consists of evaluation of the effect of the crude antibiotic preparations on microbial forms resistant to various antibiotics. The efficiency of the biological method is shown. It provides more complete and rapid characterization of the properties of the new antibiotics and their rough identification at early screening stages. 相似文献
28.
S M Cha?kovskaia P S Braginskaia N P Tochenaia V M Grigor'eva N E Klimova 《Antibiotiki》1978,23(2):171-173
The efficiency of 3 variants of the method for determination of microbial flora was compared on the injection preparation of potassium benzylpenicillin artificially infected with Staph. aureus 209P and the spores of Bac. subtilis ATCC 6633 in different doses and with different amounts of the preparation in the vials. The procedure of the preparation dissolution in the vial with the thioglycol medium containing penicillinase proved to be most effective. The microbe detection amounted to 100 per cent. The procedure was less labour- and time-consuming since addition of penicillinase to each vial with the thioglycol medium was excluded. The risk of the medium occasional infection with microbial flora during the assay was decreased. 相似文献
29.
Summary Chromium applied to a noncalcareous soil at 50 ppm did not decrease yields of bush beans (Phaseolus vulgaris L. var Improved Tendergreen), but when EDTA (ethylenediamine tetraacetic acid) was added with it, it did. Very little Cr was present in leaves. In solution culture 10-5
M Cr and higher were toxic. With solution culture the highest level of Cr in leaves was about 30 ppm and in general there was a decreasing gradient in Cr from roots to stems to leaves. EDTA had less effect in solution cultures on Cr toxicity because the Cr was already in solution. Chromium toxicity decreased cation levels in plants. 相似文献
30.
The paper describes the studies on definition of penicillinacylase localizations in the cells of E. coli with the help of ferritin labeled immune sera and electron microscopy. Both the intact cells and the cells treated with the substances affecting the cell wall intactness were used. The study showed relation between penicillinacylase and the surface structures of the cell, i.e. the cell wall and the periplasmic areas. It was found that penicillinacylase got into the environmental medium with the splitted cell fragments which corresponded to the general mechanism of excretion of large high molecular compounds by gramnegative organisms. 相似文献