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971.
The synthesis of presumptive procollagen messenger ribonucleic acid in the calvaria of the developing chick embryo 总被引:1,自引:0,他引:1
D Breitkreutz L Diaz de Leon L Paglia M Zeichner J Wilczek R Stern 《Biochimica et biophysica acta》1978,517(2):349-359
The presumptive messenger RNAs for type I procollagen were isolated from chick embryo calvaria at various stages of development. Poly(A)-containing RNA fractions from denaturing sucrose gradients directed protein synthesis in a cell-free system derived from wheat germ. Procollagen mRNA activity was detected in a region of about 26 S. Approx. 80% of the labeled proline incorporated into cell-free product was susceptible to digestion by purified bacterial collagenase. The synthesis of procollagen mRNAs was followed during development. Comparison of the in vitro labeled mRNAs from calvaria of day 12--16 embryos indicated that the 26 S component was most pronounced at day 13 and decreased progressively towards day 16. In addition, incubation of calvaria with tritiated nucleosides for 1.5--25 h revealed that 26 S mRNA was significantly labeled only after prolonged periods. The results suggest that procollagen mRNA is a relatively stable species with a prolonged half-life compared to the majority of mRNAs in this tissue. 相似文献
972.
S. N. Mukhopadhyay E. Camargo Rubio A. Ornelas Vale G. Casarrubias Arcos J. Ibarra Leon 《Biotechnology letters》1979,1(5):217-220
Summary In deseeded opuntia juice medium batch and continuous cultivation ofCandida utilis produced 12 and 19.9gl–1 yield of the SCP respectively. Its biological value(72), digestibility coefficient(70) and protein score(58) indicated it to be a good protein. 相似文献
973.
Leon J. Goodman 《Radiation and environmental biophysics》1979,16(4):367-371
Summary When detailed neutron energy spectrum data are lacking for a mixed field of neutrons and photons, it is permissible when estimating the dose equivalent to assume that the quality factor for the neutrons is 10. With this assumption, it is shown that the responses of a tissue-equivalent ionization chamber and a Geiger-Müller dosimeter can be used to obtain an acceptable approximation of the dose equivalent in the mixed field without requiring precise knowledge of the relative neutron sensitivity of the Geiger-Müller dosimeter.This investigation was supported by Contract EP-78-S-02-4733 from the Department of Energy to the Radiological Research Laboratory/Department of Radiology and by Grant No. CA13696 to the Cancer Center/Institute of Cancer Research, awarded by National Cancer Institute, DHEW 相似文献
974.
The flavonoid glycosides of both varieties of Elmera racemosa were isolated and identified. The compounds were the monoglucosides of kaempferol, quercetin and myricetin, the rutinosides of the same aglycones, and the rhamnosylrutinosides of kaempferol and quercetin. All glycosides were linked at position-3 of the flavonols. The two varieties (var. racemosa and var. puberulenta C. L. Hitchcock) were identical. A comparison of the flavonoid chemistry of Elmera, Heuchera, and Tellima supports the existence of Elmera as a genus. A survey of several collections of Tellima grandiflora, Heuchera micrantha, and H. cylindrica showed only minor quantitative differences in the two-dimensional thin layer chromatograms from collection to collection. The possible origin of Tellima and Elmera from ancestral stock having Heuchera-like flavonoid chemistry is discussed. 相似文献
975.
Leon Sedlaczek Adam Jaworski Danuta Wilmańska 《Applied microbiology and biotechnology》1981,13(3):155-160
Summary The rate of cortexolone 11-, and 11-hydroxylation by the mycelium ofCunninghamella elegans was much higher than that of its sporangiospores. In the course of the transformation, the sum of the free amino acid pools was not diminished in the spores where as it was decreased by 30–40% in the mycelium. The content of the nicotinamide nucleotides varied also in both forms of the microorganism. In the mycelium the NADP(H) pool was shown to be more reduced. The role of NADPH-generating system of the amino acid degradation and other regulation mechanisms in steroid hydroxylations by spores and mycelium ofC. elegans are discussed. 相似文献
976.
977.
Light-induced changes in the period of the circadian rhythm of carbon dioxide output in Bryophyllum leaves 总被引:1,自引:1,他引:0
Summary The period of the rhythm of carbon dioxide output from leaves of Bryophyllum fedtschenkoi R. Hamet et Perrier at 15°C was shorter in continuous white light than in darkness. The period was monitored in leaves exposed to narrow spectral bands of monochromatic radiation at an incident quantum flux density of 4.7×10-11 einsteins cm-2s-1. Bands centred on 660, 600, 730 and 530 nm significantly shortened the period, the greatest effect being achieved at 660 nm and the smallest at 530 nm; those centred on 760 and 450 nm were without effect. None of the bands tested significantly lengthened the period. The period of the rhythm in leaves exposed continuously to monochromatic radiation at 660 nm decreased with increasing quantum flux density. The extent to which a quantum flux density of 4.7×10-11 einsteins cm-2s-1 at wavelength 660 nm shortened the period depended on the ambient temperature. At 15°C a significant reduction of 4.4 h occurred as compared with the dark control, while at 30°C no significant reduction was observed. The transient (the time from the initiation of the rhythm to the first peak) showed a greater dependence on temperature than did the steady-state period. No such difference could be detected in relation to the intensity or quality of irradiation. The reduction of the transient by the various irradiation treatments was, in general, proportional to the reduction of the period. 相似文献
978.
Leon Axel 《Bulletin of mathematical biology》1976,38(6):671-677
The Kedem-Katchalsky equations for fluid flux across membranes may not be adequate for large solvent flows. In particular,
for an example of two membranes in series, it is argued that they would predict physically unreasonable behavior. An alternate
equation for solute flow is proposed for a simple sieving membrane. For the same example, this equation predicts more physically
reasonable results. 相似文献
979.
Of 1,504 strains of anaerobic bacteria tested, 544 produced acid from glucose-1-phosphate. Of these, 535 were fermentative strains of Bacteroides; only three fermentative Bacteroides strains were negative. The reaction may be useful for determination of the number of Bacteroides species present in colon content and feces. 相似文献
980.
G. E. Wilkins 《CMAJ》1976,114(3):241-243
A 51-year-old woman with a 20-year history of severe hypertension and target organ damage had nondiuretic hypokalemia, kaluresis, suppressed plasma renin activity and elevated urinary excretion of aldosterone. Renal arteriography demonstrated unilateral renal artery stenosis secondary to fibromuscular hyperplasia. Blood pressure responded only minimally to almost all antihypertensive agents. Spironolactone, 300 to 400 mg/d, produced distinct improvement in blood pressure, which was maintained for 13 months. 相似文献