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991.
Matrix metalloproteinases (MMPs) are widely distributed in vertebrate tissues and form a large family consisting of at least four distinct subfamilies. Higher vertebrate MMP-13 is well-known as collagenase-3, which represents the third member of a collagenase subfamily. In this study, we cloned cDNA coding for a unique fish homologue of human MMP-13 from a rainbow trout fibroblast cDNA library. The cDNA was 2.1 kb long and contained an open reading frame encoding a protein of 475 amino acids. The catalytic domain of the protein was 66% identical to the human counterpart with the greatest degree of identity occurring in the zinc binding site. In addition, it possessed three amino-acid residues (Tyr122, Asp233 and Gly235) characteristic of the collagenase subfamily, together with a six residue insertion which did not occur in the collagenase subfamily. Then the isolated cDNA was expressed in Escherichia coli and the recombinant protein was found to degrade gelatin and skin type I collagen. It is worth noting that rainbow trout type I collagen was more susceptible to proteolysis with the recombinant protein when compared with the calf one. It appeared that the recombinant protein also cleaved the nonhelical regions of rainbow trout muscle type V collagen. These results have revealed that the cDNA encodes a unique MMP-13 of rainbow trout. This is the first report of cDNA coding for fish MMP capable of degrading type I collagen. 相似文献
992.
993.
994.
Nobuyuki Yamagishi Youhei Saito Keiichi Ishihara Takumi Hatayama 《European journal of biochemistry》2002,269(16):4143-4151
Hsp105alpha is one of the major mammalian heat shock proteins that belongs to the HSP105/110 family, and is expressed at especially high levels in the brain as compared with other tissues in mammals. Previously, we showed that Hsp105alpha prevents stress-induced apoptosis in neuronal PC12 cells, and is a novel anti-apoptotic neuroprotective factor in the mammalian brain. On the other hand, we have also demonstrated that Hsp105alpha is expressed transiently at high levels during mouse embryogenesis and is found not only in various tissues but also in apoptotic cells. In the present study, to elucidate the role of Hsp105alpha during mouse embryogenesis, we established mouse embryonal F9 cell lines that constitutively over-express Hsp105alpha. Over-expression of Hsp105alpha enhanced hydrogen peroxide-induced apoptosis by enhancing the activation of caspase-3, poly(ADP-ribose)polymerase cleavage, cytochrome c release and activation of p38 mitogen-activated protein kinase (p38). Furthermore, oxidative stress-induced apoptosis was suppressed by SB202190, a potent inhibitor of p38, in F9 cells. These findings indicated that the activation of p38 is an essential step for apoptosis in F9 cells and that Hsp105alpha enhances activation of p38, release of cytochrome c and caspase activation. Hsp105alpha may play important roles in organogenesis, during which marked apoptosis occurs, by enhancing apoptosis during mouse embryogenesis. 相似文献
995.
3,4-Dihydroxy-2-hydroxymethylpyrrolidine, which has not been encountered naturally before, was isolated from the Pteridophyte Arachniodes standishii. Its configuration was determined as 2,3-cis and 3,4-trans from NMR spectra. 相似文献
996.
Takeshi Hashimoto Toshio Kawamata Naoaki Saito Masahiro Sasaki Masamichi Nakai Sanyoung Niu Taizo Taniguchi Akira Terashima Minoru Yasuda Kiyoshi Maeda Chikako Tanaka 《Journal of neurochemistry》1998,70(3):1289-1298
Abstract: To investigate isoform-specific roles of Ca2+ /calmodulin-dependent phosphatase [calcineurin (CaN)] in ischemia-induced cell death, we raised antibodies specific to CaN Aα and CaN Aβ and localized the CaN isoforms in the hippocampal CA1 region of Mongolian gerbils subjected to a 5-min occlusion of carotid arteries. In the nonischemic gerbil, immunoreactions of both isoforms were highly enriched in CA1 regions, especially in the cytoplasm and apical dendrites of CA1 pyramidal neurons. At 4–7 days after the induced ischemia, immunoreactivities of the CaN Aα isoform in CA1 pyramidal cells were markedly reduced, whereas they were enhanced in the CA1 radiatum and oriens layers. In contrast, CaN Aβ immunoreactivities were reduced in all layers of the ischemic CA1 region, whereas they were enhanced in activated astrocytes, colocalizing with glial fibrillary acidic protein. These findings suggest that up-regulation of CaN Aα in afferent fibers in CA1 and up-regulation of CaN Aβ in reactive astrocytes may be involved in neuronal reorganization after ischemic injury. 相似文献
997.
The effects of low concentrations of deoxynivalenol (DON) on structural and functional characteristics of human colonic adenocarcinoma
cell lines Caco-2 and T84 were examined. Scanning electron microscopic (SEM) analysis of the apical surfaces of Caco-2 cells
revealed reduction or abnormal formation of brush borders in the presence of 50, 100 and 200 ng/ml of DON. Monolayer integrity
of Caco-2 and T84 cells was studied using cells which were cultured on permeable membranes. The transepithelial electrical
resistance (TEER) of Caco-2 cells was significantly reduced at 50, 100 and 200 ng/ml of DON, significant increase in lucifer
yellow (LY) permeability was also observed in these cells at 100 ng/ml of DON. The TEER of T84 cells was significantly reduced
at 100 and 200 ng/ml of DON. LY permeability significantly increased at 200 ng/ml of DON in T84 cells. Enzyme activities in
Caco-2 cells were also examined. Alkaline phosphatase activity was reduced from the 6th to 15th day of culture in the presense
of 100 or 200 ng/ml of DON, whereas sucrase- isomaltase activity was significantly decreased by adding 50 or 100 ng/ml of
DON for 15 or 20 days. Protein content was attenuated only by treatment with 200 ng/ml of DON thoughout the experimental period.
The results indicate that DON interferes with structural and functional characteristics of differentiation in enterocytes
at low doses.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
998.
A. Sekizawa Atsushi Taguchi Akira Watanabe Takehiko Kimura Hiroshi Saito Takumi Yanaihara Takeshi Sato 《Human genetics》1998,102(4):393-396
We have extended a previously developed method that allows prenatal DNA diagnosis of female fetuses through the isolation
of single nucleated erythrocytes from maternal blood by developing a method that can distinguish between maternal and fetal
nucleated erythrocytes. Nucleated erythrocytes were separated by a density-gradient method and then collected by micromanipulation.
Sex was determined after primer extension preamplification (PEP) of the entire genome of a single cell, and human leukocyte
antigen (HLA)-DQ α type was determined after further amplification of this gene. The HLA-DQ α genotype of fetal erythrocytes
in maternal blood samples and their corresponding paternal and maternal lymphocytes were successfully determined in all cases.
The accuracy of the method was determined by using single nucleated erythrocytes from umbilical cord blood from five normal
deliveries. This is the first demonstration that the fetal HLA-DQ α gene sequences can be identified in a small aliquot of
a single nucleated erythrocyte in maternal blood. We believe that this method ushers in a new era in which the reliability
and accuracy of noninvasive prenatal DNA diagnosis from maternal blood is markedly improved.
Received: 18 April 1997 / Accepted: 1 October 1997 相似文献
999.
1000.