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排序方式: 共有192条查询结果,搜索用时 15 毫秒
1.
Hitoshi Sawada Hideyoshi Yokosawa Shin-Ichi Ishii Motonori Hoshi 《Molecular reproduction and development》1982,5(3):291-301
The presence of a protease has been demonstrated in sperm of the solitary ascidian, Halocynthia roretzi, by using t-butyloxycarbonyl-L-Val-L-Pro-L-Arg-4-methylcoumaryl-7-amide (Boc-Val-Pro-Arg-MCA) and other arginyl or lysyl MCA derivatives as substrates. Several properties of the enzyme were investigated in a crude extract. The activity had a pH optimum near 8.0 and was enhanced by the addition of CaCl2. The Km value of 87μM was determined for Boc-Val-Pro-Arg-MCA under the optimal conditions. An apparent molecular weight was estimated to be 35,000 by gel filtration. The enzyme was inhibited with diisopropyl fluorophosphate, leupeptin, antipain, p-aminobenzamidine, Val-Pro-Arg-CH2Cl, and soybean trypsin inhibitor, but scarcely inhibited with chymostatin, elastatinal, p-chloromercuribenzoic acid, tosyl-Lys-CH2Cl, and tosyl-Phe-CH2Cl. Boc-Val-Pro-Arg-MCA, the most susceptible of the substrates examined, showed the most effective inhibition against fertilization of ascidian eggs. Thus, this enzyme in ascidian sperm extract has features closely similar to mammalian acrosin [EC 3.4.21.10], and we conclude that the enzyme is involved in fertilization as one of the lysins. 相似文献
2.
An efficient method, called the culture plate method, was devised for microinjection of foreign materials into nuclei of tomato callus cells. The culture plate method, used in this study, is advantageous because cells suitable for microinjection can be selected microscopically and the injected cells subsequently cultured in the same plate. With this microinjection system, some foreign materials were injected into nuclei of callus cells without causing detrimental effects. Kanamycin-resistant callus clones were obtained 1 month after injection from single cells whose nuclei were microinjected with a NPT II DNA fragment of the pE2KX plasmid. 相似文献
3.
Léonie A. E. Huijser Martine Bérubé Andrea A. Cabrera Rui Prieto Mónica A. Silva Jooke Robbins Naohisa Kanda Luis A. Pastene Mutsuo Goto Hideyoshi Yoshida Gísli A. Víkingsson Per J. Palsbøll 《Conservation Genetics》2018,19(4):1007-1024
Currently, three stocks of sei whales (Balaenoptera borealis) are defined in the North Atlantic; the Nova Scotian, Iceland-Denmark Strait and Eastern North Atlantic stocks, which are mainly based upon historical catch and sighting data. We analyzed mitochondrial control region DNA (mtDNA) sequences and genotypes from 7 to 11 microsatellite loci in 87 samples from three sites in the North Atlantic; Iceland, the Gulf of Maine and the Azores, and compared against the North Pacific using 489 previously published samples. No statistically significant deviations from homogeneity were detected among the North Atlantic samples at mtDNA or microsatellite loci. The genealogy estimated from the mtDNA sequences revealed a clear division of the haplotypes into a North Atlantic and a North Pacific clade, with the exception of one haplotype detected in a single sample from the Azores, which was included in the North Pacific clade. Significant genetic divergence between the North Atlantic and North Pacific Oceans was detected (mtDNA ΦST?=?0.72, microsatellite Weir and Cockerham’s ? = 0.20; p?<?0.001). The coalescent-based estimate of the population divergence time between the North Atlantic and North Pacific populations from the sequence variation among the mtDNA sequences was at 163,000 years ago. However, the inference was limited by an absence of samples from the Southern Hemisphere and uncertainty regarding mutation rates and generation times. The estimates of inter-oceanic migration rates were low (Nm at 0.007 into the North Pacific and at 0.248 in the opposite direction). Although estimates of genetic divergence among the current North Atlantic stocks were low and consistent with the extensive range of movement observed in satellite tagged sei whales, the high uncertainty of the genetic divergence estimates precludes rejection of multiple stocks in the North Atlantic. 相似文献
4.
Mohamad Radwan Almofti Hideyoshi Harashima Yasuo Shinohara Ammar Almofti Wenhao Li Hiroshi Kiwada 《Molecular membrane biology》2013,30(1):35-43
In order to identify factors affecting cationic Iiposome-mediated gene transfer, the relationships were examined among cationic liposome/DNA complex (lipoplex)-cell interactions, lipoplex size and lipoplex-mediated transfection (lipofection) efficiency. It was found that lipofection efficiency was determined mainly by lipoplex size, but not by the extent of lipoplex-cell interactions including binding, uptake or fusion. In addition, it was found that serum affected mainly lipoplex size, but not lipoplex-cell interactions, which effect was the major reason behind the inhibitory effect of serum on lipofection efficiency. It was concluded that, in the presence or absence of serum, lipoplex size is a major factor determining Iipofection efficiency. Moreover, in the presence or absence of serum, lipoplex size was found to affect lipofection efficiency by controlling the size of the intracellular vesicles containing lipoplexes after internalization, but not by affecting lipoplex-cell interactions. In addition, large lipoplex particles showed, in general, higher lipofection efficiency than small particles. These results imply that, by controlling lipoplex size, an efficient lipid delivery system may be achieved for in vitro and in vivo gene therapy. 相似文献
5.
Hideyoshi Yoshida Miki Shirakihara Akira Takemura Kunio Shirakihara 《Marine Mammal Science》1994,10(3):266-282
Development, sexual dimorphism, and individual variation were examined in the skeleton of the finless porpoise in the coastal waters of western Kyushu, Japan. Skulls ceased growing by 4 yr. Postcranial skeletons ceased increasing in size at an age older than 11 yr. The finless porpoise was estimated to attain cranial maturity by 4 yr and physical maturity at 14–23 yr. Sexual dimorphism was not detectable in most of the cranial characters but was detected in more than half of the postcranial characters. Females tended to show larger values of postcranial characters. The shape of the pelvic bone was obviously different between males and females. Thus, a discriminant function was proposed to determine sex using measurements of this bone. Individual variation was greatest in the feeding apparatus such as length of the rostrum, and least in the braincase. 相似文献
6.
Shimizu M Gruz P Kamiya H Kim SR Pisani FM Masutani C Kanke Y Harashima H Hanaoka F Nohmi T 《EMBO reports》2003,4(3):269-273
Deranged oxidative metabolism is a property of many tumour cells. Oxidation of the deoxynucleotide triphosphate (dNTP) pool, as well as DNA, is a major cause of genome instability. Here, we report that two Y-family DNA polymerases of the archaeon Sulfolobus solfataricus strains P1 and P2 incorporate oxidized dNTPs into nascent DNA in an erroneous manner: the polymerases exclusively incorporate 8-OH-dGTP opposite adenine in the template, and incorporate 2-OH-dATP opposite guanine more efficiently than opposite thymine. The rate of extension of the nascent DNA chain following on from these incorporated analogues is only slightly reduced. These DNA polymerases have been shown to bypass a variety of DNA lesions. Thus, our results suggest that the Y-family DNA polymerases promote mutagenesis through the erroneous incorporation of oxidized dNTPs during DNA synthesis, in addition to facilitating translesion DNA synthesis. We also report that human DNA polymerase η, a human Y-family DNA polymerase, incorporates the oxidized dNTPs in a similar erroneous manner. 相似文献
7.
Eggs of the ascidian Halocynthia roretzi are activated by insemination and by treatment with calcium ionophore, leading to elevation of the vitelline coat. Here we describe the effects on egg activation of microinjection of guanosine 5'-(γ thio) triphosphate (GTPγS, a non-hydrolyzable GTP analog), heparin (an antagonist of the inositol 1,4,5-trisphosphate receptor) and a monoclonal antibody to the Rho GTP-binding protein. Microinjected GTPγS induced elevation of the vitelline coat, but not when it was co-injected with EGTA or heparin. Pre-injected heparin or the anti-Rho monoclonal antibody blocked subsequent sperm-induced elevation of the vitelline coat, but not calcium ionophore-induced elevation. We also demonstrated that the amount of cytosolic inositol 1,4,5-trisphosphate was increased by insemination. These results strongly suggest that the Rho GTP-binding protein functions prior to the heparin-blocked inositol 1,4,5-trisphosphate receptor-mediated Ca2+ release in the sperm induced activation process of H. roretzi eggs. 相似文献
8.
A -glucuronidase gene was introduced directly into barley (Hordeum vulgare L. cv. Kobinkatagi) coleoptile cells by microinjection and transient expression of the gene was examined. Inner epidermis tissue of coleoptiles was excised and injected with plasmid DNA, pBI221, carrying cauliflower mosaic virus 35S promoter, -glucuronidase gene, and a nopaline synthase polyadenylation region. Histochemical assay for -glucuronidase production showed positive enzyme activity only in coleoptile cells injected with plasmid DNA. Expression of the -glucuronidase gene was examined chronologically using honogenates of injected coleoptile tissues. Glucuronidase activity first appeared after 6 hr, reached the maximum level 24 hr after injection, and decreased afterwards. These results suggest that microinjection of coleoptile tissues may be a useful approach for the genetic engineering of Gramineae plants in which protoplast regeneration is difficult. 相似文献
9.
Azumi K Usami T Kamimura A Sabau SV Miki Y Fujie M Jung SJ Kitamura S Suzuki S Yokosawa H 《Zoological science》2007,24(12):1231-1240
A serious disease of the ascidian Halocynthia roretzi has been spread extensively among Korean aquaculture sites. To reveal the cause of the disease and establish a monitoring system for it, we constructed a cDNA microarray spotted with 2,688 cDNAs derived from H. roretzi hemocyte cDNA libraries to detect genes differentially expressed in hemocytes between diseased and non-diseased ascidians. We detected 21 genes showing increased expression and 16 genes showing decreased expression in hemocytes from diseased ascidians compared with those from non-diseased ascidians. RT-PCR analyses confirmed that the expression levels of genes encoding astacin, lysozyme, ribosomal protein PO, and ubiquitin-ribosomal protein L40e fusion protein were increased in hemocytes from diseased ascidians, while those of genes encoding HSP40, HSP70, fibronectin, carboxypeptidase and lactate dehydrogenase were decreased. These genes were expressed not only in hemocytes but also in various other tissues in ascidians. Furthermore, the expression of glutathione-S transferase omega, which is known to be up-regulated in H. roretzi hemocytes during inflammatory responses, was strongly increased in hemocytes from diseased ascidians. These gene expression profiles suggest that immune and inflammatory reactions occur in the hemocytes of diseased ascidians. These genes will be good markers for detecting and monitoring this disease of ascidians in Korean aquaculture sites. 相似文献
10.
Yoshihiro Takikawa Koji Kakutani Teruo Nonomura Yoshinori Matsuda Hideyoshi Toyoda 《Mycoscience》2011,52(3):204-209
In the present study, using a high-fidelity digital microscope, we observed the sequence of appressorial development on the
germ tubes of a powdery mildew fungus isolated from red clover leaves. Based on its morphological characteristics and rDNA
internal transcribed spacer (ITS) sequences, the fungus was identified as Erysiphe trifoliorum, and one of its isolates, designated as KRCP-4N, was used in this work. The conidial germination of isolate KRCP-4N was studied
on host (red clover) and non-host (barley) leaves, as well as on an artificial hydrophobic membrane (Parafilm). More than
90% of conidia germinated synchronously and developed dichotomous appressoria (symmetrical double-headed appressoria) on all
substrata used. On host leaves, all appressorium-forming conidia developed hyphae (colony-forming hyphae) from conidial bodies
without extending germ tubes from the tips of the appressoria. On non-host leaves and on Parafilm-covered glass slides, however,
all conidia extended germ tubes from one side of dichotomous appressoria (two-step germination). In addition to the dichotomous
appressoria, we detected a few conidia that produced hooked appressoria and extended germ tubes from the tip of the appressorium.
Penetration attempts by KRCP-4N conidia on barley leaves were impeded by papillae formed at penetration sites beneath these
two types of appressorium. From these results, we conclude that the “two-step germination” of E. trifoliorum KRCP-4N conidia is the result of an unsuccessful penetration attempt, causing diversity in appressorial shape. 相似文献