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1.
Hideaki Naoe Tatsuyuki Chiyoda Jo Ishizawa Kenta Masuda Hideyuki Saya Shinji Kuninaka 《Biochemical and biophysical research communications》2013,430(2):757-762
Differentiation of placental trophoblast stem (TS) cells to trophoblast giant (TG) cells is accompanied by transition from a mitotic cell cycle to an endocycle. Here, we report that Cdh1, a regulator of the anaphase-promoting complex/cyclosome (APC/C), negatively regulates mitotic entry upon the mitotic/endocycle transition. TS cells derived from homozygous Cdh1 gene-trapped (Cdh1GT/GT) murine embryos accumulated mitotic cyclins and precociously entered mitosis after induction of TS cell differentiation, indicating that Cdh1 is required for the switch from mitosis to the endocycle. Furthermore, the Cdh1GT/GT TS cells and placenta showed aberrant expression of placental differentiation markers. These data highlight an important role of Cdh1 in the G2/M transition during placental differentiation. 相似文献
2.
Chromatin was prepared from the buds and cotyledons of Alaskapea seedlings. The dissociated chromosomal components in thepresence of 2 M NaCl and 5 M urea were completely fractionatedinto DNA and proteins with a Bio-Gel A50 column. The proteinswere recovered by (NH4)2SO4 and further fractionated into histonesand non-histone proteins using a Bio-Rex 70(Na+) column. Thedifference in the ratios of histones to non-histone proteinsbefore and after chromatography with the Bio-Rex 70 was lessthan 10%. The histones and non-histone proteins thus preparedshowed typical protein absorption spectra. Polyacrylamide gelelectrophoresis of histones showed that the histone compositionsin buds and cotyledon were similar, but the amount of HI histoneswas a little less in cotyledons than in buds. Unlike histones,non-histone proteins fractionated by SDS-polyacrylamide gelelectrophoresis indicated distinct differences between the twotissues. Buds had more heterogeneous non-histone proteins, atleast 13 polypeptides, than cotyledons did. On the other hand,non-histone proteins of cotyledons showed less heterogeneityand lacked proteins of high molecular weight which were foundin buds. (Received May 6, 1976; ) 相似文献
3.
The sensitivity of the agar plate method for the diagnosis of Strongyloides stercoralis was studied experimentally. Results demonstrated that this method was sensitive enough to detect S. stercoralis even when only a few worms were present. 相似文献
4.
Expression of hepatitis B virus middle and large surface antigen genes in Saccharomyces cerevisiae. 总被引:4,自引:0,他引:4 下载免费PDF全文
T Imamura M Araki A Miyanohara J Nakao H Yonemura N Ohtomo K Matsubara 《Journal of virology》1987,61(11):3543-3549
The hepatitis B virus genome carries the surface antigen (SAg) gene and an open reading frame that encodes two SAg-related polypeptides: SAg with a 55-amino-acid N-terminal extension polypeptide and SAg with a 174-amino-acid N-terminal extension polypeptide. These are termed middle S and large S, respectively. These polypeptides or their glycosylated derivatives have been detected in Dane particles, but their chemical and biological properties have remained largely unknown because of their limited availability. We attempted to produce these proteins in Saccharomyces cerevisiae by placing the coding regions under the control of the promoter of the yeast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. Yeast cells carrying middle S and large S coding sequences produced 33,000- and 42,000-dalton products, respectively, each of which reacted with anti-S antibody and bound to polymerized human serum albumin, in accordance with the known properties of pre-S proteins from particles in human sera (K. H. Heermann, U. Goldmann, W. Schwartz, T. Seyffarth, H. Baumgarten, and W. H. Gerlich, J. Virol. 52:396-402, 1984; A. Machida, S. Kishimoto, H. Ohnuma, K. Baba, Y. Ito, H. Miyamoto, G. Funatsu, K. Oda, S. Usuda, S. Togami, T. Nakamura, Y. Miyakawa, and M. Mayumi, Gastroenterology 86:910-918, 1984). The middle S polypeptide is glycosylated and can be assembled into particles whose size and density are similar to those of SAg. However, this polypeptide was highly susceptible to proteolytic degradation into 29,000- and 26,000-dalton polypeptides, of which only the former retained the binding activity to polymerized albumin. The large S polypeptides are nonglycosylated, relatively stable, and do not seem to assemble into particles by themselves. 相似文献
5.
Yoshikazu Izumi Pijush Kanti Nath Hiroshi Yamamoto Hideaki Yamada 《Applied microbiology and biotechnology》1989,30(4):337-342
Summary A convenient and efficient method of NADPH production from NADP+ has been established using a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans IFO 3172. Using airdried cells of the bacterium, the optimum conditions for NADPH production were examined, including the cell and glucose concentrations, NADP+ concentration, pH, buffer and reaction temperature. Under suitable conditions, the conversion ratio and the amount of NADPH accumulated reached about 100% and 73 mg/ml of the reaction mixture, respectively, after 1-h reaction. Intact cells of the bacterium also showed high NADPH production even in the reaction mixture without a surfactant. The addition of Triton X-100 to the reaction mixture and freeze-thawing treatment of intact cells enhanced the production. The NADPH production method was further improved by using cells of the bacterium immobilized by entrapment in a -carrageenan gel lattice. The immobilized cells had almost the same enzymatic properties as the air-dried cells. The conditions for the continuous production of NADPH with an immobilized cell column were also investigated. NADPH was produced in a good yield (about 95%) with this continuous process. 相似文献
6.
7.
Katsuhiko Yanagisawa Hideaki Ishigro Kiyotoshi Kaneko Tadashi Miyatake 《Neurochemical research》1990,15(5):483-486
The vacuolar degeneration of central myelin was produced in Sprague-Dawley rats by oral administration of triethyl tin. The wet weight of brain stems which seems to reflect the degree of accumulation of water increased during the administration of the toxin, whereas the activity of 2, 3-cyclic nucleotide 3-phosphodiesterase altered less remarkably. When TET was withdrawn from the drinking water, the rats showed a dramatic clinical improvement along with reduction in wet weight of brain stems. Treatment with acetazolamide following TET inhibited the clinical improvement and reduction in wet weight of brain stems. The present results indicates that central myelin has plasticity in recovering from the vacuolar degeneration by removing the accumulated fluid and carbonic anhydrase is possibly involved in the dehydration, of myelin in such a recovery phase. 相似文献
8.
Hiroshi Suzuki Hideaki Taguchi Kazuko Nishimura Makoto Miyaji Akira Nakamura Hironori Nakajima 《Mycopathologia》1988,104(1):7-17
Summary The authors succeeded in establishing a murine model of systemic candidiasis being disseminated from the primary gastrointestinal lesions caused by oral inoculation of Candida albicans. Using this model, an attempt was made for detecting the Candida antigen by enzyme-linked immunosorbent assay using avidin-biotin (AB-ELISA) from the serum of infected mice.Gastrointestinal candidiasis was formed in all of the 20 mice treated with the drugs (antibiotics, antineoplastic agents, hydrocortisone, etc.) and inoculated orally with C. albicans. Fourteen of these mice suffered from submucosal candidiasis, and C. albicans was cultured from the visceral organs in 12 of them. The assay by AB-ELISA was able to detect 1.0 ng/ml Candida mannan in the mouse serum. The Candida antigen was detected in the sera of 11 of the 14 mice with submucosal candidiasis. However, the antigen could not be detected in the sera of the 6 mice with intramucosal candidiasis.The assay by AB-ELISA is more sensitive and specific for the diagnosis of systemic candidiasis than other serological assays. 相似文献
9.
Proton extrusion from cucumber roots decreased markedly duringCa2+ starvation in the presence of KC1. Vesicles with ATP-dependentproton transport activity were prepared from the microsomalmembrane fraction of control and Ca2+-starved roots. The protontransport rate of the vesicles from Ca2+-starved roots was repressedto less than half of the vesicles prepared from the controlroots. K+-Mg2+-ATPase activity associated with the vesiclesprepared from Ca2+-starved roots was approximately one-thirdof the activity associated with those prepared from controlroots. Km values of the proton transport rate and K+-Mg2+-ATPasefor ATP were much higher in vesicles prepared from Ca2+-starvedroots. The repression of proton extrusion linked with K+ uptake inthe Ca2+-starved roots could be largely caused by the reducedproton pumping activity associated with microsomal membranesin the roots. (Received May 25, 1987; Accepted October 14, 1987) 相似文献
10.
Increase in Proton-Transport Activity of Tonoplast Vesicles as an Adaptive Response of Barley Roots to NaCl Stress 总被引:2,自引:0,他引:2
H+-Transport activity of the vesicles prepared from barley rootswas studied at the early phase after application of NaCl stress.The activity reached maximal level at 3 days after the treatmentwith 200 mM NaCl which moderately reduced the growth. This activityincrease could be suppressed in the presence of cycloheximideand actinomycin D. The properties of the membrane vesicles associated with H+-transportactivity prepared from both control and NaCl-stressed rootssuggested that it was of tonoplast origin based on the followingfindings: optimal pH at 7.5, strong inhibition by nitrate butnot by vanadate, and stimulation by chloride. The density gradient centrifugation of vesicles with DextranT70 did not show any detectable difference in the distributionpatterns of H+-transport activities between control and NaClstressedroots. Furthermore, Km values for ATP of the H+-transport activityof vesicles prepared from control and NaCl-stressed roots werethe same. Therefore, H+-transport activity with properties similarto those of the control roots was increased by NaCl stress.The results are discussed in terms of an adaptive mechanismof barley against salt stress.
1Permanent address: Department of Horticulture, College of Agriculture,Chonnam National University, Chonnam 500, Korea. (Received April 18, 1988; Accepted July 20, 1988) 相似文献