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41.
42.
Jianyu Zheng Kohei Irifune Kouji Hirai Masashi Nakata Ryuso Tanaka Hiromichi Morikawa 《Journal of plant research》1994,107(4):365-369
In situ hybridization with a biotin-labeled rice ribosomal DNA (rDNA) probe to the somatic metaphase chromosomes of six species ofPhaseolus andVigna (P. angularis, P. calcaratus, P. coccineus, P. vulgaris, V. sesquipedalis andV. sinensis) was done to determine the sites of rDNA. Hybridization signals were present in the terminal and subterminal chromosome regions
of each of the six species. The number of rDNA sites was two inP. angularis andP. calcaratus, four inP. coccineus andP. vulgaris, and six inV. sesquipedalis andV. sinensis. 相似文献
43.
Yoshihito Shirai Masaaki Yamaguchi Atsuko Kobayashi Akihiro Nishi Hisao Nakamura Hiroki Murakami 《Cytotechnology》1994,14(2):129-146
The growth yields for glucose and glutamine of murine hybridoma cells entrapped in collagen gel particles were examined during the growth phase. The immobilized hybridoma cells were cultivated in a fluidized bed fermenter where the medium was circulating to supply oxygen separately. Procedures to supply an alkaline solution for adjusting the pH level strongly affected the growth yields. A direct supply of the alkaline solution to the cultivation system reduced both the growth yields for glucose and glutamine, probably due to a local increase in pH level. On the other hand, when fresh medium in which the pH was adjusted to around 8.5 was added to the cultivation system, the growth yields were unchanged even at the same pH level as when direct alkaline supply was used. These results suggest that an indirect alkaline supply could be recommended to ajust the pH level when using medium-circulating-fermenters. 相似文献
44.
Ruairí A. Mac Síomóin Noboru Nakata Tatuo Murai Masanosuke Yoshikawa Hiroyuki Tsuji & Chihiro Sasakawa 《Molecular microbiology》1996,19(3):599-609
The virulent phenotype of Shigella requires loci on the chromosome as well as on the large virulence plasmid, and is regulated via a complex web of interactions amongst various chromosomal and large plasmid genes. To further investigate the role of chromosomal loci in virulence, we performed random Tn 10 mutagenesis in Shigella flexneri YSH6000T, and isolated an avirulent mutant (V3404) incapable of spreading throughout an epithelial cell monolayer. Although V3404 initially spread intercellularly at the same rate as the wild-type, it gradually slowed down and ceased spreading as a result of increasing defects in cell division, leading to the formation of long filamentous bacteria lacking septa, trapped within cells. In addition, the mutation affected the ability of V3404 to polymerize actin, a prerequisite for intra- and inter-cellular spreading ability. Sequencing of Tn 10 -flanking DNA revealed that the mutated gene, designated ispA (intracellular septation), was equivalent to a previously sequenced but uncharacterised gene of Escherichia coli located between trp and tonB . Using E. coli sequence data, we cloned the ispA gene from the YSH6000T chromosome and found that it complemented the V3404 mutation. Nucleotide sequencing and in vitro expression experiments revealed that ispA coded for a small (21 kDa), very hydrophobic protein. These results thus show that ispA is an essential virulence gene affecting several functions of the virulence process. 相似文献
45.
46.
Akihiro Yoshida Kuniaki Takata Toshiko Kasahara Toshio Aoyagi Shozo Saito Hiroshi Hirano 《The Histochemical journal》1995,27(5):420-426
Summary Glucose is actively absorbed in the intestine by the action of the Na+-dependent glucose transporter. Using an antibody against the rabbit intestinal Na+-dependent glucose transporter (SGLT1), we examined the localization of SGLT1 immunohistochemically along the rat digestive
tract (oesophagus, stomach, duodenum, jejunum, ileum, colon and rectum). SGLT1 was detected in the small intestine (duodenum,
jejunum and ileum), but not in the oesophagus, stomach, colon or rectum. SGLT1 was localized at the brush border of the absorptive
epithelium cells in the small intestine. Electron microscopical examination showed that SGLT1 was localized at the apical
plasma membrane of the absorptive epithelial cells. SGLT1 was not detected at the basolateral plasma membrane. Along the crypt-villus
axis, all the absorptive epithelial cells in the villus were positive for SGLT1, whose amount increased from the bottom of
the villus to its tip. On the other hand, cells in the crypts exhibited little or no staining for SGLT1. Goblet cells scattered
throughout the intestinal epithelium were negative for SGLT1. These observations show that SGLT1 is specific to the apical
plasma membrane of differentiated absorptive epithelial cells in the small intestine, and suggest that active uptake of glucose
occurs mainly in the absorptive epithelial cells in the small intestine. 相似文献
47.
Ken Lee Akihiro Ito †Kunio Koshimura †Tetsuya Ohue †Yasutaka Takagi †Soichi Miwa 《Journal of neurochemistry》1995,64(2):874-882
Abstract: Hypoxia is known to disturb neuronal signal transmission at the synapse. Presynaptically, hypoxia is reported to suppress the release of neurotransmitters, but its postsynaptic effects, especially on the function of neurotransmitter receptors, have not yet been elucidated. To clarify the postsynaptic effects, we used cultured bovine adrenal chromaffin cells as a model of postsynaptic neurons and examined specific binding of l -[3 H]nicotine (an agonist for nicotinic acetylcholine receptors: nAChRs) and 22 Na+ flux under control and hypoxic conditions. Experiments were performed in media preequilibrated with a gas mixture of either 21% O2 /79% N2 (control) or 100% N2 (hypoxia). Scatchard analysis of the specific binding to the cells revealed that the KD under hypoxic conditions was twice as large as that under control conditions, whereas the B max was unchanged. When the specific [3 H]nicotine binding was kinetically analyzed, the association constant ( k 1 ) but not the dissociation constant ( k −1 ) was decreased to 40% of the control value by hypoxia. When the binding assay was performed using the membrane fraction, these changes were not observed. Nicotine-evoked 22 Na+ flux into the cells was suppressed by hypoxia. In contrast, specific [3 H]quinuclidinyl benzilate binding to the intact cells was unaffected by hypoxia. These results demonstrate that hypoxia specifically suppresses the function of nAChRs (and hence, neuronal signal transmission through nAChRs), primarily by acting intracellularly. 相似文献
48.
An algal suspension containing protoplasmic detritus [termed, single cell detritus (SCD)] was prepared from freeze-dried fronds
of Ulva and its dietary value to Artemia nauplii was tested after size fractionation. The dissolved fraction (<0.22 μm) ofthe
Ulva suspension contained ca. 48% of theoriginal protein in the Ulva, but had no dietaryvalue to Artemia, which is a suspension
feeder. In contrast, the fraction passing through a 100-μm meshand containing SCD of 2–14 μm in diameter, contributedto the
survival of Artemia. The fraction remaining on the 100 μm mesh was further incubated with and without the bacterium Pseudoalteromonas
espejiana strain AR06 FERM BP-5024. The bacterium degraded
Ulva forming new SCD over 106 mL -1 level as rapidly as by 16 h of incubation. The dietary
value of Ulva for Artemia growth was elevated over four times by the incubation. The protein content of the SCD
was approximately doubled by the attaching of bacteria, suggesting the enhanced Artemia growth is attributable to
the combined effect of the SCD and the bacteria. Development of a hatchery diet from Ulva , a resource with a low
commercial value, is suggested utilizing the degrading and attaching ability of P. espejiana.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
49.
Xiaoliang Liu Akemi Ota Michiko Watanabe Shigeharu Ueda Atsushi Saitoh Hideo Shinagawa Atsuo Nakata Takashi Kurimura Xiaoui Wang Yu Zhao Kiyoshi Kondo Jiro Seki Shinichi Miyake Nobuo Sakato Hajime Fujio 《Microbiology and immunology》1995,39(10):775-785
We investigated the murine antibody response to recombinant p17 (rp17) of human immunodeficiency virus type 1 (HIV-1) and the human antibody response directed to p17 in HIV-1 infection. Three large peptides covering residues 12-29, 53-87 and 87-115 of p17 were synthesized. The cysteine residues 57 and 87 of peptide 53-87 were reoxidized to form a disulfide bridge. Eighteen out of 19 murine monoclonal anti-rp17 antibodies had relatively high affinities (KA = 1.9 × 105?1.4 × 108 M?1) with one of the 3 p17 peptides in the liquid phase. Each monoclonal antibody reacted only with one particular peptide and had no reactivity with the other 2 p17 peptides. All the monoclonal antibodies reacted with rp17 in the liquid phase with a reasonable degree of affinity (KA = 2.0 × 105?1.8 × 107 M?1). Four HIV-1 carrier sera, which were positive in ELISA using rp17 as the antigen, reacted positively in an ELISA using 3 p17 peptides which were used to titrate murine monoclonal antibodies. Murine monoclonal antibodies having specificity for the 3 p17 peptides stained live HIV-1-infected cells by means of indirect membrane immunofluorescence, irrespective of their specificity. This suggests that the various portions of p17 (at least 3 regions of p17) were exposed on the surface of live infected cells, probably as short polypeptide chains. 相似文献
50.
Isozyme type 1 of alkaline phosphatase in Escherichia coli K-12 was converted to types 2 and 3 after incubation of type 1 isozyme with the supernatant of a sonicated cell-free extract prepared from the cells carrying the cloned iap+ gene on a multi-copy plasmid. By comparison, the lysate prepared from cells carrying the iap+ gene only on the chromosome showed much less isozyme-converting activity. The reaction was promoted by Mg2+ at concentrations of 10 to 50 mM. Protease inhibitors, antipain and leupeptin which inhibit the isozyme conversion in vivo, also inhibited the isozyme conversion in vitro. These results suggest that cells carrying the multiple copy iap+ plasmid overproduce a kind of proteolytic enzyme which removes the amino-terminal arginine residues from isozymes 1 and 2. 相似文献