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941.
942.
The sequence of the 5.8 S ribosomal RNA of the crustacean Artemia salina. With a proposal for a general secondary structure model for 5.8 S ribosomal RNA. 总被引:11,自引:11,他引:0 下载免费PDF全文
We report the primary structure of 5.8 S rRNA from the crustacean Artemia salina. The preparation shows length heterogeneity at the 5'-terminus, but consists of uninterrupted RNA chains, in contrast to some insect 5.8 S rRNAs, which consist of two chains of unequal length separated in the gene by a short spacer. The sequence was aligned with those of 11 other 5.8 S rRNAs and a general secondary structure model derived. It has four helical regions in common with the model of Nazar et al. (J. Biol. Chem. 250, 8591-8597 (1975)), but for a fifth helix a different base pairing scheme was found preferable, and the terminal sequences are presumed to bind to 28 S rRNA instead of binding to each other. In the case of yeast, where both the 5.8 S and 26 S rRNA sequences are known, the existence of five helices in 5.8 S rRNA is shown to be compatible with a 5.8 S - 26 S rRNA interaction model. 相似文献
943.
Four nonconjugative broad-host-range cloning vectors were derived from the W-plasmid Sa. They are small (Mr 5.6?7.2 × 106), carry several drug-resistance markers, and allow constructing and screening for recombinant plasmids generated by the restriction enzymes EcoRI, PstI, BglII, HindIII, BamHI and SalI, 相似文献
944.
F. Gosselé M. Van den Mooter L. Verdonck J. Swings J. De Ley 《Antonie van Leeuwenhoek》1981,47(4):289-296
The nitrogen requirements of 96Gluconobacter, 55Acetobacter and 7Frateuria strains were examined. Only someFrateuria strains were able to grow on 0.5% yeast extract broth or 0.5% peptone broth. In the presence ofd-glucose ord-mannitol as a carbon source, ammonium was used as the sole source of nitrogen by all three genera. With ethanol, only a fewAcetobacter strains grew on ammonium as a sole nitrogen source. Singlel-amino acids cannot serve as a sole source of carbon and nitrogen for growth ofGluconobacter, Acetobacter orFrateuria. The singlel-amino acids which were used by most strains as a sole nitrogen source for growth are: asparagine, aspartic acid, glutamine,
glutamic acid, proline and alanine. SomeAcetobacter andGluconobacter strains deaminated alanine, asparagine, glutamic acid, threonine, serine and proline. NoFrateuria strain was able to develop on cysteine, glycine, threonine or tryptophan as a sole source of nitrogen for growth. An inhibitory
effect of valine may explain the absence of growth on this amino acid. No amino acid is “essential” forGluconobacter, Acetobacter orFrateuria. 相似文献
945.
Calcitroic acid was recently identified as a major metabolite of 1,25-dihydroxyvitamin D3 (Esvelt, Schnoes, and DeLuca, Biochemistry 18, 3977, 1979). The metabolite was found to have little, although significant, activity in healing rickets, and causing bone mineral mobilization but elicited no significant elevation in intestinal calcium transport. The compound showed little affinity for either the serum 25-hydroxyvitamin D binding protein or the intestinal cytosol receptor for 1,25-dihydroxyvitamin D3. Various tissues of the rat were examined for the presence of calcitroic acid following a 120-ng dose of 1,25-dihydroxy-[3α-3H]vitamin D3. The metabolite was detected in liver, intestinal mucosa, kidneys, and blood with livers and mucosa containing the highest concentrations. In each of these tissues the calcitroic acid content increased during the period between 4 and 12 h after the dose. The presence of calcitroic acid in femurs was indicated but could not be confirmed. Bile duct cannulation reduced but did not abolish the intestinal calcitroic acid content. In addition to calcitroic acid, other polar metabolites of 1,25-dihydroxyvitamin D3 were detected in these experiments. 相似文献
946.
947.
R. De Boer 《Genetica》1982,58(1):17-22
A case of non-reciprocal hybrid infertility between strains of the spider mite Tetranychus urticae Koch is described. Evidence is presented that the infertility results from an interaction between a chromosomal and a cytoplasmic factor. The presence or absence of the cytoplasmic factor seems to be controlled also by chromosomal genes. 相似文献
948.
A study of the puffing patterns of the Jst, J1, U1–2, U1–2–8 and Ust chromosomal arrangements of Drosophila subobscura, from different geographical origins, has been carried out. Twenty-eight puffs were observed, 10 on the J chromosome, and 18 on the U chromosome. No differences, whether qualitative or quantitative, have been found between the puffing pattern of the J chromosome, whether from the same of different geographical background. In the U chromosome, the U1–2 and U1+2+8 arrangements show the same puffing pattern, and neither quantitative nor qualitative differences were found. However, the puffing pattern of these chromosomes alters considerably in the Ust arrangement of the K228 laboratory strain. 相似文献
949.
A comparative study of the heat resistance ( D 60 values) of four Saccharomyces spp. and two Kluyveromyces spp. (21 strains) showed a 30–350-fold higher heat resistance of ascospores than of vegetative cells. It was also observed that small numbers of ascospores exhibiting a considerably higher heat resistance can easily be formed, even in a complete vegetative growth medium. This phenomenon may have led most other authors to report none or only slight differences between the heat resistance of yeast ascospores and their vegetative cells. Until more information has been collected about the ascospore load of acid (fruit) products and their heat resistance, accurate calculations of the minimum F values for heat preservation of these products may not be possible. 相似文献
950.
H. J. Lindeboom H. A. J. De Klerk-V. D. Driessche A. J. J. Sandee 《Aquatic Ecology》1982,16(1):93-102
Summary During five 28-hours measurements in 1981, the oxygen production and consumption in an eelgrass community in saline Lake Grevelingen were investigated using light plexiglass enclosures. Applying a conversion factor of 0.29 the amount of carbon fixed and the amount of organic carbon mineralized were estimated. Gross and net production were estimated over 24-hours periods.There appeared to be a good correlation between production and insolation on the water surface. For every measurement period the production as a function of light and aboveground eelgrass biomass in the enclosure were calculated. This showed a maximum of 5.10–6 mg C.J.–1 g dry weight–1 in April and minimum of 1.4.10–6 mg C.J.–1 g–1 in August.Using the calculated production coefficients, the insolation and the eelgrass biomass the gross production, net production and consumption during the growing season of 1976 were calculated. Gross production amounted to 340 gC.m–2, and net production came to 130 g C.m–2. Approximately 60 gC.m–2 was respired by the eelgrass plants while the remaining 150 gC.m–2 was consumed or mineralized by other organisms on the sampling spot. Approximately 120 g C.m–2.yr–1 was transported by wind and wave action towards the eastern part of the lake where it became anaerobically degraded. This resulted in the formation of sulfide and methane.Communication no. 236 of the Delta Institute for Hydrobiological Research, Yerseke, The Netherlands. 相似文献