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971.
N Koide K Sakaguchi Y Koide K Asano M Kawaguchi H Matsushima T Takenami T Shinji M Mori T Tsuji 《Experimental cell research》1990,186(2):227-235
Adult rat hepatocytes formed floating multicellular spheroids in primary culture in an uncoated plastic dish with a positively charged surface. Cells in the spheroids formed in such a simple way were similar to those formed in dishes coated with proteoglycan fraction isolated from rat liver reticulin fibers; in both cases, cells maintained high ability to produce albumin and poor ability to proliferate in response to epidermal growth factor. Coating dishes with albumin was also helpful in spheroid formation; coating with 2-hydroxymethyl methacrylate resulted in formation of incomplete spheroids. Elimination of serum factors was essential for the formation of spheroids; when cells were washed with serum-containing medium before seeding or if the medium was replaced with a serum-containing medium, spheroid formation was completely inhibited. Collagens, fibronectin, and laminin, all of which promote the adhesion and spreading of hepatocytes on substrates, inhibited spheroid formation. Furthermore, collagens disintegrated spheroids, and cells in the monolayer initiated proliferation. Thus, two distinct, mutually exclusive features of primary culture of adult hepatocytes apparently exist; monolayer culture with proliferative activity in an adherent environment and spheroid culture with poor proliferative activity and high albumin-producing ability in a nonadherent environment. 相似文献
972.
973.
974.
Sakae Fukunaga Takashi Jintoku Yumiko Iwata Mamoru Nakayama Takashi Tsuji Nagayoshi Sakaya 《Geomicrobiology journal》2013,30(7-8):361-370
Microbiological characteristics of bentonite deposits were investigated as a natural analogue of microbial behavior in the buffer material for geological disposal of radioactive waste. Distributions of microorganisms in bentonite were examined at four sites in two different bentonite deposits in Japan. The sites included pond bottom, wetland, and wet mine gallery environments where bentonite layers have been left undisturbed for 2 to 30 years. Excavation was performed without using drilling water and the center parts of the cores were used for microbial examination. Plate counts with R2A medium of aerobic and anaerobic bacteria at the drilling mouth ranged from 105 to 107/g DW (dry weight) and from 103 to 106/g DW, respectively. The CFDA-AM (Carboxyfluorescein diacetate acetoxymethyl ester) cell counts ranged from 106 to 109/g DW. Bacterial numbers in the bentonite layers declined with distance from the drilling mouth; both aerobes and anaerobes were less than 102/g DW and CFDA-AM cell counts less than 106/g DW for core samples taken from approximately 1 m depth, except at the pond bottom. These results suggest that microbial activity in natural bentonite is lower than in typical soils and aquatic sediments and does not spread easily. 相似文献
975.
Uptake of uridine by a long-day duckweed, Lemna gibba G3 wasexamined. Km and Vmax for uptake were in the range of 1 to 2x105 M and of 5 to 10 x108 moles/g fresh weight/2hr, respectively. Uptake rate depended on temperature, and theoptimum pH was 5.0. Uridine uptake was competitively inhibitedby some compounds structurally analogous to uridine. However,the activity of uridine kinase was not affected by these compounds,except for cytidine. Uridine uptake was inhibited by metabolicinhibitors, in which uridine taken up was left unconverted toother forms, especially in the presence of DNP. These resultssuggest that uridine was taken up into the duckweed celb bya specific transport system and immediately phosphorylated byuridine kinase. Phosphorylation of uridine was not associatedwith the uridine transport reaction. (Received November 15, 1976; ) 相似文献
976.
977.
The formation of gamma-aminobutyric acid (GABA) from putrescine was examined in organs of rats using radioactive putrescine. Radioactive GABA was detected in all the organs of a rat injected intraperitoneally with radioactive putrescine, and the highest radioactivity of GABA was observed in the small intestine. The enzyme involved in this formation was purified from small intestine and identified as a diamine oxidase, histaminase, from the properties of the enzyme. Activity of the enzyme was found in all the organs of rat, and the highest activity was observed in the small intestine. 相似文献
978.
Jian Zhu Yingqian Kang Jun Uno Hideaki Taguchi Ying Liu Mihoko Ohata Reiko Tanaka Maria Luiza Moretti Yuzuru Mikami 《Mycopathologia》2010,169(1):47-55
We applied multilocus microsatellite typing (MLMT) method to investigate the genetic relation between Cryptococcus neoformans var. grubii clinical and environmental isolates in S?o Paulo, Brazil. This MLMT method includes three functional gene sequences of C. neoformans var. grubii, which are dispersed on three chromosomes. In all, 89 strains (36 clinical and 53 environmental isolates) were analyzed.
Of 36 clinical strains, 20 belonged to a major type of MLMT-13 (55.6%). They were mainly isolated from clinical specimens.
About 52.8% of strains from the environment belong to a major type of MLMT-36, which are indigenous to environments and which
were not isolated from clinical samples. Thus, we recognized two genotypes that distinguish majority of clinical and environmental
strains. No differences were found in antifungal susceptibility and capsule size between major environmental and clinical
MLMT types. 相似文献
979.
J Nakajima-Shimada H Iida F I Tsuji Y Anraku 《Biochemical and biophysical research communications》1991,174(1):115-122
Aequorin is a Ca2(+)-binding protein that emits light upon reacting with Ca2+ and has been used as a probe for monitoring changes in the intracellular free Ca2+ concentration, [Ca2+]i. The protein consists of three components: apoaequorin (apoprotein), molecular oxygen and a chromophore. The present study was designed to conditionally express the apoaequorin cDNA of the jellyfish Aequorea victoria under the control of the GAL1 promoter in the yeast Saccharomyces cerevisiae and to investigate whether apoaequorin can be accumulated in high enough concentration in the cells to detect a Ca2+ signal in vitro. The results showed that the cells accumulated sufficient amounts of recombinant apoaequorin when incubated in the galactose-based medium and that the protein was active and not toxic to the cells, suggesting that the recombinant apoaequorin may be applicable to monitoring changes in [Ca2+]i in intact yeast cells. 相似文献
980.