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1.
When spores of the fern,Pteris multifida, were aseptically cultured in the dark, sporophytic plants were apogamously induced. The plants have been subsequently grown
in pots until the development of leaves with many sporangia for observations of meiotic characteristics in their sporocytes.
The sporophytic plants originated from spores were estimated to be haploid, and the estimation was supported by abnormal meiosis
in sporocytes and the absence of mature spores, but some chromosomes (n=58) formed bivalents in the meiotic process. 相似文献
2.
Kuwahara Michio; Ishibashi Kenichi; Gu Yong; Terada Yoshio; Kohara Yuji; Marumo Fumiaki; Sasaki Sei 《American journal of physiology. Cell physiology》1998,275(6):C1459
A genome project focusingon the nematode Caenorhabditis elegans has demonstrated thepresence of eight cDNAs belonging to the major intrinsic proteinsuperfamily. We functionally characterized one of these cDNAs namedC01G6.1. Injection of C01G6.1 cRNA increased the osmotic waterpermeability (Pf) of Xenopusoocytes 11-fold and the urea permeability 4.5-fold but failed toincrease the glycerol permeability. It has been speculated that the MIPfamily may be separated into two large subfamilies based on thepresence or absence of two segments of extra amino acid residues (~15amino acids) at the second and third extracellular loops. BecauseC01G6.1 (designated AQP-CE1), AQP3, and glycerol facilitator (GlpF) all have these two segments, we replaced the segments of AQP-CE1 with thoseof AQP3 and GlpF to identify their roles. The functional characteristics of these mutants were principally similar to that ofwild-type AQP-CE1, although the values of Pf andurea permeability were decreased by 39-74% and 28-65%,respectively. These results suggest that the two segments of extraamino acid residues may not contribute to channel selectivity orformation of the route for small solutes. 相似文献
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Yusuke Nakamura Michio Ogawa Takahiro Nishide Mitsuru Emi Goro Kosaki Seiichi Himeno Kenichi Matsubara 《Gene》1984,28(2):263-270
The nucleotide sequences of the cloned human salivary and pancreatic α-amylase cDNAs correspond to the continuous mRNA sequences of 1768 and 1566 nucleotides, respectively. These include all of the amino acid coding regions. Salivary cDNA contains 200 bp in the 5′-noncoding region and 32 in the 3′-noncoding region. Pancreatic cDNA contains 3 and 27 bp of 5′- and 3′-noncoding regions, respectively. The nucleotide sequence humology of the two cDNAs is 96% in the coding region, and the predicted amino acid sequences are 94% homologous.Comparison of the sequences of human α-amylase cDNAs with those previously obtained for mouse α-amylase genes (Hagenbuchle et al., 1980; Schibler et al., 1982) showed the possibility of gene conversion between the two genes of human α-amylase. 相似文献
6.
Cell hybridization of phytohemagglutinin (PHA)-stimulated human peripheral blood lymphocytes (PBL) with murine lymphoma (EL-4) provided three hybridomas (MHH-16, MHH-20, and MHH-22) which spontaneously produced human mitogenic factor (MF). MHH-16 was serially subcloned by limiting dilution procedures, which resulted in maintaining two subclones producing human MF spontaneously for more than one year (PQL-3 and PQL-5 subcloned lines). Human MF (MHH-MF) derived from supernatants of PQL-5 line cultures had a molecular weight (m.w.) of about 26,000–30,000 daltons (the major peak) with a minor peak with an m.w. of 15,000 daltons on Sephadex G-100 chromatography, and at a high concentration of NaCl (1 m), the activity of the 26,000–30,000-m.w. fraction became weak and that of the 15,000-m.w. fraction became predominant. MHH-MF had an isoelectric point of pH 5.0–6.5. On DEAE-cellulose chromatography, MHH-MF was eluted at a fairly low salt concentration (sodium phosphate buffer 0.02 M, pH 8.0, NaCl 10 mm). After periodate treatment of this MHH-MF, the mitogenic activity almost disappeared. MHH-MF was relatively unstable to heating at 56 C for 20 min. In the presence of tunicamycin (0.3μg/ml), an inhibitor of N-linked glycosylation, the synthesized MHH-MF showed a decrease in m.w. as follows: the major peak shifted from 26,000–30,000 to 23,000 daltons and the minor peak from 15,000 to 10,000 daltons on Sephadex G-100 chromatography. In internal labeling experiments with [3H]leucine, the 3H-labeled MF was partially purified, with mitogenic activity as a guide. This 3H-labeled MHH-MF fraction could be absorbed by PHA blasts but not by normal PBL. On SDS-PAGE under reducing conditions, only the radioactive peak of the 15,000-dalton fraction was recovered. MHH-MF obtained from the hybridoma culture supernatants may be a dimer of the 15,000-dalton fraction and a glycoprotein. 相似文献
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Inositol deficiency of Schizosaccharomyces pombe did not induce significant change of contents of various cellular components except for phospholipids and inositol. The most remarkable decrease in inositol content by the deficiency occurred in the mitochondrial fraction. Electronmicroscopic observation of the inositol-deficient cells of Sch. pombe showed no remarkable thickening of cell wall as occurred in the inositol-exacting mutant of Saccharomyces cerevisiae Strain A–21–20.Marked loss of fermentative activity under the aerobic condition was caused from inositol deficiency without significant change of activities of respiration and anaerobic fermentation. This seemed to indicate elevated regulatory control of the fermentative activity by oxygen in the inositol-deficient Sch. pombe.Phosphorylative activities of intact cells and the isolated mitochondria coupled with oxidation was also remarkably suppressed by inositol deficiency. 相似文献
9.
Inhibition of the Bacterial Cell Wall Synthesis in vitro by Enduracidin,a New Polypeptide Antibiotic
Michio Matsuhashi Ikuko Ohara Yoshihiro Yoshiyama 《Bioscience, biotechnology, and biochemistry》2013,77(1):134-137
Adenosine 5′-phosphosulfate (APS) kinase from a thermophilic bacterium, Bacillus st ear other mophilus, was purified to apparent homogeneity. The apparent molecular weight was 50 kDa, consisting of two 26-kDa subunits. The enzyme was very thermostable and lacked cysteine and methionine residues. Enzyme activity was more stimulated with Mn2 + , Zn2 +, or Co2 + than with Mg2 + and the Km for ATP and APS were 220 µM and 42 µM, respectively. 相似文献
10.
Hisataka Shikama Motoyuki Yajima Michio Ui 《Biochimica et Biophysica Acta (BBA)/General Subjects》1980,631(2):278-288
Hepatic glycogen metabolism was studied in rats during the period of transition from the fed to fasted states. Glycogenic activity was measured in vivo based on the incorporation of [14C]glucose into liver glycogen. Its changes were almost parallel to the changes in glucogen synthase activity. Progressive accumulation of liver glycogen that occurred in the fed state was associated with a proportional increase in glycogenic activity. Within 4 h after the cessation of food intake, glycogenic activity showd a precipitous fall from the peak to its nadir without significant changes in glycogen content. Meanwhile, the glucose concentration in the portal vein decreased. Upon further development of fasting, glycogenic activity displayed a progressive regain, reciprocally as glycogen contents gradually decreased. The precipitous fall of glycogenic activity during the transition from the fed to fasted states was associated with a transient increase in plasma glucagon, and was partly overcome by the injection of anti-glucagon serum. It is concluded that the fall of portal venous concentration of glucose and secretion of glucagon act as a signal to initiate liver glycogen metabolism characteristics of the fasted or postabsorptive state. 相似文献