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151.
Plasma and erythrocyte enzyme activities were measured in ddY mice supplemented with dietary selenium (Se) from baker's yeast (Saccharomyces serevisiae) or selenious acid at 0.3 ppm Se content. Glutathione peroxidase (GSHpx) activities increased significantly in erythrocytes from mice supplemented with dietary Se. It was concluded that addition of dietary Se as food additive is very effective for activation of GSHpx in mice. 相似文献
152.
Self‐superparasitism can be profitable (i.e., a fitness gain) when conspecific female adult parasitoids prefer singly parasitized hosts over doubly parasitized hosts. This preference is expected to evolve when the value (i.e., the fitness gain from oviposition) of doubly parasitized hosts is lower than that of singly parasitized hosts. We examined whether such a preference is found in the small brown planthopper, Laodelphax striatellus (Fallén) (Homoptera: Delphacidae), and its semisolitary infanticidal parasitoid Echthrodelphax fairchildii Perkins (Hymenoptera: Dryinidae). We compared the preferences and host values between each of four pairs of double and triple parasitism, each of which had the same time interval between the first and last oviposition bouts. Ovipositions on doubly and singly parasitized hosts occurred with similar frequencies in each of the four pairs, even though the doubly parasitized hosts were of lower value than the singly parasitized hosts. However, the value of doubly parasitized hosts with the first and second parasitoid offspring on the same side of the host was higher than that of hosts with the two offspring on different sides, and the value of the former did not differ significantly from that of singly parasitized hosts. The preferences between singly and doubly parasitized hosts with the two offspring on the same or different sides were as expected from differences in their values, except for one pair of double and triple parasitisms. This exception is considered attributable to an imperfect ability to evaluate hosts. 相似文献
153.
Emi Takeda Kohei Kunimoto Yoshito Kawai Misumi Kataoka Kazuhiko Ishikawa Takashi Nakamura 《Extremophiles : life under extreme conditions》2016,20(5):733-745
O-Phosphoserine sulfhydrylase (OPSS) synthesizes cysteine from O-phospho-l-serine (OPS) and sulfide. We have determined the three-dimensional structures of OPSS from hyperthermophilic archaeon Aeropyrum pernix K1 (ApOPSS) in complex with aminoacrylate intermediate (AA) formed from pyridoxal 5′-phosphate with OPS or in complex with cysteine and compared them with that of ApOPSS. We found an orientational change of F225 at the active-site entrance and constructed an F225A mutant to examine its activities and AA stability and clarify the role of F225 in ApOPSS. The OPS and O-acetyl-l-serine (OAS) sulfhydrylase activities of the F225A mutant decreased by 4.2- and 15-fold compared to those of the wild-type (wt) ApOPSS, respectively. The ability of OPS and OAS to form AA also decreased by 12- and 27-fold, respectively. AA was less stable in the F225A mutant than in the wt ApOPSS. Simulated docking showed that leaving groups, such as phosphate and acetate, were oriented to the inside of the active site in the F225A mutant, whereas they were oriented to the entrance in the wt ApOPSS. These results suggest that F225 in ApOPSS plays important roles in maintaining the hydrophobic environment of AA from solvent water and in controlling the orientation of leaving groups. 相似文献
154.
Loss of heterozygosity (LOH) of loci on chromosome 18q occurs in a majority of colorectal cancers. The DPC4/SMAD4 gene, lying in close proximity to the DCC gene at 18q21.1, was recently identified as a candidate tumor suppressor for the genesis of pancreatic cancer as well as a predisposing gene for Juvenile Polyposis Syndrome (JPS). The gene product functions as a cytoplasmic mediator in the signaling pathway of transforming growth factor beta (TGF-beta). To investigate the potential role of DPC4/SMAD4 gene in colorectal cancers, we examined 73 tumors of clinical stages II or III from Japanese patients, for LOH at 18q21 and also for subtle mutations anywhere within the coding region of DPC4/SMAD4. LOH was identified in 50 (78%) of the 64 tumors that were informative for polymorphic markers in the region. Somatic mutations were identified in seven of those tumors: two frameshift mutations, a 1-bp deletion (326 del T) in exon 8 and a 1-bp insertion (50-51 ins A) in exon 1; two nonsense mutations, Arg445Ter in exon 10 and Glu538Ter in exon 11; and three missense mutations, Asn129Lys in exon 2, Tyr95Asn in exon 2, and Asp355Glu in exon 8. Three of the seven mutations were observed in the mad homology 1 (MH1) domain encoded by exons 1 and 2. In all of the tumors carrying intragenic mutations of one allele, LOH analysis had shown that the other allele was missing. The results demonstrated that inactivation of both alleles of the DPC4/SMAD4 gene occurs in a substantial proportion of advanced colorectal cancers, and that the DPC4/SMAD4 gene probably exerts a tumor-suppressor effect for colorectal carcinogenesis that fulfills the criterion of the two-hit concept proposed by Knudson [A.G. Knudson, Hereditary cancer, oncogenes, and anti-oncogenes, Cancer Res. 45 (1985) 1437-1443.]. 相似文献
155.
Isolation of NotI clusters hypomethylated in HBV-integrated hepatocellular carcinomas by two-dimensional electrophoresis. 总被引:2,自引:0,他引:2
H Nagai M Baba N Konishi Y S Kim M Nogami K Okumura M Emi K Matsubara 《DNA research》1999,6(4):219-225
To examine genetic and epigenetic alterations associated with HBV integration in hepatocarcinogenesis, we compared genomic DNA profiles of primary hepatocellular carcinomas (HCCs) and cell lines that either contained or did not contain integrated HBV. To accomplish this, we carried out Restriction Landmark Genomic Scanning (RLGS), a two-dimensional system that displays 2000-3000 Not I landmark sites in a single gel electrophoresis experiment. We identified one Not I landmark spot that showed high signal intensity in HBV-integrated cell lines or in primary HCCs, but not in HCCs or tumor-cell lines free of HBV integration. Cloning of this spot revealed that it consisted of a Not I cluster sequence enriched with CpG dinucleotides. This sequence, hypomethylated in association with HBV integration, was found in the peri-centromeric region of human acrochromosomes. The results demonstrate that epigenetic changes at specific sequences in the genome occur in association with HBV integration during the process of hepatocarcinogenesis. 相似文献
156.
In the central nervous system, astrocytes produce erythropoietin (Epo) and neurons express its receptor. To examine whether
or not the brain Epo protects the in vitro cultured neurons from glutamate-induced cell death, we established rat astrocyte
cell lines containing the plasmid for production of recombinant rat Epo. Epo partially purified from the culture medium showed
a neuroprotective effect similar to that of rat Epo produced by Chinese hamster ovary (CHO) cells. Comparison was made in
some other properties between Epo produced by these astrocyte cell lines and that by CHO cells. Digestion of Epo with glycosidases
indicated that there was a little difference in glycosylation of Epo produced by two types of the cells.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
157.
158.
Kenta Haga Manabu Yamazaki Satoshi Maruyama Masami Kawaharada Ayako Suzuki Emi Hoshikawa Nyein Nyein Chan Akinori Funayama Toshihiko Mikami Tadaharu Kobayashi Kenji Izumi Jun-ichi Tanuma 《Translational oncology》2021,14(12)
Cancer-associated fibroblasts (CAFs) have important roles in promoting cancer development and progression. We previously reported that high expression of sex-determining region Y (SRY)-box9 (SOX9) in oral squamous cell carcinoma (OSCC) cells was positively correlated with poor prognosis. This study developed three-dimensional (3D) in vitro models co-cultured with OSCC cells and CAFs to examine CAF-mediated cancer migration and invasion in vitro and in vivo. Moreover, we performed an immunohistochemical analysis of alpha-smooth muscle actin and SOX9 expression in surgical specimens from 65 OSCC patients. The results indicated that CAFs promote cancer migration and invasion in migration assays and 3D in vitro models. The invading OSCC cells exhibited significant SOX9 expression and changes in the expression of epithelial–mesenchymal transition (EMT) markers, suggesting that SOX9 promotes EMT. TGF-β1 signalling inhibition reduced SOX9 expression and cancer invasion in vitro and in vivo, indicating that TGF-β1-mediated invasion is dependent on SOX9. In surgical specimens, the presence of CAFs was correlated with SOX9 expression in the invasive cancer nests and had a significant impact on regional recurrence. These findings demonstrate that CAFs promote cancer migration and invasion via the TGF-β/SOX9 axis. 相似文献
159.
Identification of heteromolecular binding sites in transcription factors Sp1 and TAF4 using high‐resolution nuclear magnetic resonance spectroscopy 下载免费PDF全文
160.
Yasuyuki Kourogi Kenji Ogata Norito Takamura Jin Tokunaga Nao Setoguchi Mitsuhiro Kai Emi Tanaka Susumu Chiyotanda 《Theoretical biology & medical modelling》2017,14(1):8