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31.
Eiji Nitasaka Tsuneyuki Yamazaki M. M. Green 《Molecular genetics and genomics : MGG》1995,247(2):164-168
A large proportion of spontaneous mutations inDrosophila melanogaster strains of laboratory origin are associated with insertions of mobile DNA elements. As a first step toward determining whether spontaneous laboratory mutations are predictive for mutational events occurring in the wild, recessivebrown (bw) eye color mutants were isolated. By inbreeding the progeny of wild-caughtDrosophila melanogaster females,bw mutations were isolated from seven separate geographic sites distributed among Japan, California, Siberia and Hungary. Among a total of 14 mutations studied, no case of transposon mutagenesis was found. At least 4 mutations are associated with small deletions in thebw gene. The remainder are inseparable from wild-typebw by Southern analysis and are presumed to be basepair changes or very small indels. Although only two spontaneousbw mutants of laboratory origin have been analyzed molecularly, one is a mobile element insertion. 相似文献
32.
High pressure conditions stimulate expression of chloramphenicol acetyltransferase regulated by the lac promoter in Escherichia coli 总被引:1,自引:0,他引:1
Chiaki Kato Takako Sato Maria Smorawinska Koki Horikoshi 《FEMS microbiology letters》1994,122(1-2):91-96
Abstract Recombinant plasmids with the chloramphenicol acetyltransferase (CAT) structural gene behind several kinds of promoters were tested for expression in Escherichia coli during growth at atmospheric pressure (0.1 MPa) and at high pressure (30 MPa). Expression of the CAT gene from the lac promoter was remarkably activated (approx. 78-fold) by high pressure in the absence of the inducer isopropyl-β-d-thiogalactopyranoside (IPTG). The stimulation of the CAT activity by the lac promoter at high pressure did not simply result from an increased plasmid copy number, because the CAT activities from the other promoters and β-lactamase activities were unaffected at high pressure. 相似文献
33.
Identification of a basic glycoprotein induced by ethylene in primary leaves of azuki bean as a cationic peroxidase. 总被引:1,自引:1,他引:0
Ethylene causes the accumulation of seven different proteins (each designated AZxx according to its molecular mass, xx in kD) in excised primary leaves of azuki bean (Vigna angularis) (F. Ishige, H. Mori, K. Yamazaki, H. Imaseki [1991] Plant Cell Physiol 32: 681-690). A complementary DNA encoding an ethylene-induced basic glycoprotein, AZ42, from azuki bean was cloned and its complete nucleotide sequence was determined. Characterization of the cDNA was accomplished by monitoring expression of an immunoreactive protein in Escherichia coli that harbored the cDNA and by the identification of a partial amino acid sequence that was the same as that determined from the purified protein. An open reading frame (1071 base pairs) in the cDNA encoded a protein of 357 amino acids with a molecular mass of 39.3 kD. The amino acid sequence contained three regions that are highly conserved among peroxidases from eight different plants. Purified AZ42 exhibited peroxidase activity. The basic glycoprotein induced by ethylene was identified as a cationic isozyme of peroxidase. The corresponding mRNA was not present in leaves that had not been treated with ethylene, but it appeared after 1 h of treatment with ethylene and its level increased for the next 15 h. Accumulation of the mRNA was also induced after wounding or treatment with salicylate. The wound-induced increase in the level of the mRNA was suppressed by 2,5-norbornadiene, but the salicylate-induced increase was not. 相似文献
34.
Fumio Yamazaki Ryoko Sone Nobuharu Fujii Haruo Ikegami 《International journal of biometeorology》1993,37(4):212-217
Based on the hypothesis that the relation between sweating rate and body temperature should be different during exercise and rest after exercise, we compared the sweating response during exercise and recovery at a similar body temperature. Healthy male subjects performed submaximal exercise (Experiment 1) and maximal exercise (Experiment 2) in a room at 27° C and 35% relative humidity. During exercise and recovery of 20 min after exercise, esophageal temperature (Tes), mean skin temperature, mean body temperature (
), chest sweating rate (
), and the frequency of sweat expulsion (F
SW) were measured. In both experiments,
andF
SW were clearly higher during exercise than recovery at a similar body temperature (Tes,
).
was similar during exercise and recovery, or a little less during the former, at a similarF
SW. It is concluded that the sweating rate during exercise is greater than that during recovery at the same body temperature, due to greater central sudomotor activity during exercise. The difference between the two values is thought to be related to non-thermal factors and the rate of change in mean skin temperature. 相似文献
35.
The molecular events associated with decondensation of human sperm nuclei were analyzed by incubating sperm with egg extracts from an amphibian, Bufo japonicus . Acid-urea-Triton polyacrylamide gel electrophoresis (AUT-PAGE) showed that the nuclear basic proteins of human sperm consist mainly of protamines (HPI, HPII) with minor amounts of nucleosomal histones. On incubation of lysolecithin (LC)- and dithiothreitol (DTT)-treated human sperm with the egg extract, the nuclei lost HPI and HPII within 15 min in association with extensive nuclear decondensation, and the acquirement of a whole set of nucleosomal histones. Incubation of LC-DTT-sperm with nucleoplasmin purified from Bufo eggs also induced nuclear decondensation and loss of protamines within 30 min. Native-PAGE and Western blot analyses of incubation medium indicated tight association of the released protamines to nucleoplasmin, strongly suggesting that protamines are removed from sperm nuclei not enzymatically but by their specific binding to nucleoplasmin. On incubation of LC-DTT-sperm with nucleoplasmin and exogenous nucleosomal core histones, micrococcal nuclease-protected DNA fragments were released, although their unit repeat length was slightly less than that of somatic nucleosomes. Thus remodeling of human sperm during fertilization can be mimicked under defined conditions with nucleoplasmin and exogenous histones. 相似文献
36.
Kazuo Iwaki Norio Okumura Mitsuru Yamazaki 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,619(2)
A rapid and accurate determination of tetracycline antibiotics in human serum by reversed-phase high-performance liquid chromatography with fluorescence detection has been developed, based on protein precipitation in serum. Various reagents for precipitation were investigated, and 24% trichloroacetic acid in methanolic solution gave the maximum recovery (at least 94.3%) and interference-free chromatograms of different three tetracyclines. At a concentration of 0.5 μg/ml, the precision (relative standard deviation) ranged from 1.12 to 1.94%. In the range 0.04–10.0 μg/ml for oxytetracycline and chlorotetracycline and 0.01–10.0 μg/ml for tetracycline, linear responses were observed. The detection limits of this method were 10–35 ng/ml for all three antibiotics. The proposed method was applied to the determination of serum concentrations in subjects receiving tetracycline antibiotics. 相似文献
37.
Summary A model antigen, rabbit immunoglobulin G, was immobilized onto polyester cloth by adsorption. The antigen cloth was reacted with sheep anti-rabbit IgG antibody. Antibody bound to the antigen cloth was nearly quantitatively eluted by saturated MgCl2, whereas a commercial antibody eluent slowly eluted only about 70 % of the antibody. Exposure of antibody to saturated MgCl2 for 30 min resulted in no loss of immunoactivity. Saturated MgCl2, therefore, is an ideal eluent in immunoaffinity purification of antibodies. 相似文献
38.
Molecular Evolution of the Duplicated Amy Locus in the Drosophila Melanogaster Species Subgroup: Concerted Evolution Only in the Coding Region and an Excess of Nonsynonymous Substitutions in Speciation 下载免费PDF全文
From the analysis of restriction maps of the Amy region in eight sibling species belonging to the Drosophila melanogaster species subgroup, we herein show that the patterns of duplication of the Amy gene are almost the same in all species. This indicates that duplication occurred before speciation within this species subgroup. From the nucleotide sequence data, we show a strong within-species similarity between the duplicated loci in the Amy coding region. This is in contrast to a strong similarity in the 5' and 3' flanking regions within each locus (proximal or distal) throughout the species subgroup. This means that concerted evolution occurred only in the Amy coding region and that differentiated evolution between the duplication occurred in the flanking regions. Moreover, when comparing the species, we also found a significant excess of nonsynonymous substitutions. In particular, all the fixed substitutions specific to D. erecta were found to be nonsynonymous. We thus conclude that adaptive protein evolution occurred in the lineage of D. erecta that is a ``specialist' species for host plants and probably also occurs in the process of speciation in general. 相似文献
39.
Eiji Nitasaka Tsuneyuki Yamazaki M. M. Green 《Molecular & general genetics : MGG》1995,247(2):164-168
A large proportion of spontaneous mutations inDrosophila melanogaster strains of laboratory origin are associated with insertions of mobile DNA elements. As a first step toward determining whether spontaneous laboratory mutations are predictive for mutational events occurring in the wild, recessivebrown (bw) eye color mutants were isolated. By inbreeding the progeny of wild-caughtDrosophila melanogaster females,bw mutations were isolated from seven separate geographic sites distributed among Japan, California, Siberia and Hungary. Among a total of 14 mutations studied, no case of transposon mutagenesis was found. At least 4 mutations are associated with small deletions in thebw gene. The remainder are inseparable from wild-typebw by Southern analysis and are presumed to be basepair changes or very small indels. Although only two spontaneousbw mutants of laboratory origin have been analyzed molecularly, one is a mobile element insertion. 相似文献
40.
N. Yamazaki R. Ueshima J. A. Terrett S. I. Yokobori M. Kaifu R. Segawa T. Kobayashi K. I. Numachi T. Ueda K. Nishikawa K. Watanabe R. H. Thomas 《Genetics》1997,145(3):749-758
Complete gene organizations of the mitochondrial genomes of three pulmonate gastropods, Euhadra herklotsi, Cepaea nemoralis and Albinaria coerulea, permit comparisons of their gene organizations. Euhadra and Cepaea are classified in the same superfamily, Helicoidea, yet they show several differences in the order of tRNA and protein coding genes. Albinaria is distantly related to the other two genera but shares the same gene order in one part of its mitochondrial genome with Euhadra and in another part with Cepaea. Despite their small size (14.1-14.5 kbp), these snail mtDNAs encode 13 protein genes, two rRNA genes and at least 22 tRNA genes. These genomes exhibit several unusual or unique features compared to other published metazoan mitochondrial genomes, including those of other molluscs. Several tRNAs predicted from the DNA sequences possess bizarre structures lacking either the T stem or the D stem, similar to the situation seen in nematode mt-tRNAs. The acceptor stems of many tRNAs show a considerable number of mismatched basepairs, indicating that the RNA editing process recently demonstrated in Euhadra is widespread in the pulmonate gastropods. Strong selection acting on mitochondrial genomes of these animals would have resulted in frequent occurrence of the mismatched basepairs in regions of overlapping genes. 相似文献