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991.
992.
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
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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
993.
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
994.
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
995.
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
996.
997.
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
998.
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
999.
Jorge Zorzopulos Sara DeLong Virginia Chapman Lloyd M. Kozloff 《Journal of cellular biochemistry》1982,18(3):363-375
The characteristics of pure preparations of short-tail fibers of bacteriophage T4 have been studied in the optical and electron microscope. Three main structures were observed: 1) spheres of 8.1 nm diameter; 2) fibers 43 nm long and 3.8 nm thick; and 3) fibers 54 nm long and 3.2 nm thick. Both types of fibers exhibited a regular beaded appearance. The 43-nm fibers were the most abundant structure. During the process of purification of the short-tail fibers, the formation of aggregates was observed each time the material containing the short-tail fibers was dialyzed against saline solutions. These aggregates became increasingly fibrous (as observed in the optical microscope) as the material used was increasingly enriched in short-tail fibers. Finally, most of the aggregates were of the fibrous type when they were formed from a purified preparation of short-tail fibers. In the electron microscope, it was found that the filamentous aggregates were organized in well-defined bundles. The amino acid composition of the highly purified short-tail fibers was also determined. Among the known fibrous proteins, the ones that most resemble the amino acid composition of the short-tail fibers are actin and fibrinogen. These observations are discussed in relation to the T4 short-tail fiber structure and their localization on the hexagonal baseplate of the T4 tail structure. 相似文献
1000.
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