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  总被引:1,自引:0,他引:1  
Vibrio parahaemolyticus strain RIMD2210633 has two sets of genes encoding two separate type III secretion systems (T3SSs), called T3SS1 and T3SS2. T3SS2 has a role in enterotoxicity and is present only in Kanagawa phenomenon-positive strains, which are pathogenic to humans. Accordingly, T3SS2 is considered to be closely related to V. parahaemolyticus human pathogenicity. Despite this, the biological actions of T3SS2 and the identity of the effector protein(s) secreted by this system have not been well understood. Here we report that T3SS2 induces a cytotoxic effect in Caco-2 and HCT-8 cells. Moreover, it was revealed that VPA1327 (vopT), a gene encoded within the proximity of T3SS2, is partly responsible for this cytotoxic effect. The VopT shows approximately 45% and 44% identity with the ADP-ribosyltransferase (ADPRT) domain of ExoT and ExoS, respectively, which are two T3SS-secreted effectors of Pseudomonas aeruginosa. T3SS2 was found to be necessary not only for the secretion, but also for the translocation of the VopT into host cells. We also demonstrate that VopT ADP-ribosylates Ras, a member of the low-molecular-weight G (LMWG) proteins both in vivo and in vitro. These results indicate that VopT is a novel ADPRT effector secreted via V. parahaemolyticus T3SS.  相似文献   
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The orotidine-5′-phosphate decarboxylase gene of Saccharomyces exiguus Yp74L-3 was cloned as a DNA fragment complementing a ura4 mutation of this yeast. The coding region of the gene is 807 bp in length, and represents 68.7% similarity to the corresponding gene of S. cerevisiae (URA3). The cloned URA4 gene was shown to be located on the 790-kbp Chromosome (chr) VIII of S. exiguus Yp74L-3. The neighbor-joining phylogenetic tree based on the orotidine-5′-phosphate decarboxylase coding sequences indicates that S. exiguus Yp74L-3 is closely related to Kluyveromyces yeasts, as well as to a S. cerevisiae laboratory strain. Received: 4 February 2000 / Accepted: 3 July 2000  相似文献   
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Biological Trace Element Research - The essential trace element zinc maintains liver functions. Liver diseases can alter overall zinc concentrations, and hypozincemia is associated with various...  相似文献   
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Carbon and nitrogen are essential elements for life. Glucose as a carbon source and glutamine as a nitrogen source are important nutrients for cell proliferation. About 100 years ago, it was discovered that cancer cells that have acquired unlimited proliferative capacity and undergone malignant evolution in their host manifest a cancer-specific remodeling of glucose metabolism (the Warburg effect). Only recently, however, was it shown that the metabolism of glutamine-derived nitrogen is substantially shifted from glutaminolysis to nucleotide biosynthesis during malignant progression of cancer—which might be referred to as a “second” Warburg effect. In this review, address the mechanism and relevance of this metabolic shift of glutamine-derived nitrogen in human cancer. We also examine the clinical potential of anticancer therapies that modulate the metabolic pathways of glutamine-derived nitrogen. This shift may be as important as the shift in carbon metabolism, which has long been known as the Warburg effect.  相似文献   
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NO 3 ? is a major nitrogen source for plant nutrition, and plant cells store NO 3 ? in their vacuoles. Here, we report that a unique compost made from marine animal resources by thermophiles represses NO 3 ? accumulation in plants. A decrease in the leaf NO 3 ? content occurred in parallel with a decrease in the soil NO 3 ? level, and the degree of the soil NO 3 ? decrease was proportional to the compost concentration in the soil. The compost-induced reduction of the soil NO 3 ? level was blocked by incubation with chloramphenicol, indicating that the soil NO 3 ? was reduced by chloramphenicol-sensitive microbes. The compost-induced denitrification activity was assessed by the acetylene block method. To eliminate denitrification by the soil bacterial habitants, soil was sterilized with γ irradiation and then compost was amended. After the 24-h incubation, the N2O level in the compost soil with presence of acetylene was approximately fourfold higher than that in the compost soil with absence of acetylene. These results indicate that the low NO 3 ? levels that are often found in the leaves of organic vegetables can be explained by compost-mediated denitrification in the soil.  相似文献   
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The effects of hydrogen peroxide on normal and acatalasemic erythrocytes were examined. Severe hemolysis of acatalasemic erythrocytes and a small tyrosine radical signal (g = 2.005) associated with the formation of ferryl hemoglobin were observed upon the addition of less than 0.25 mM hydrogen peroxide. However, when the concentration of hydrogen peroxide was increased to 0.5 mM, acatalasemic erythrocytes became insoluble in water and increased the tyrosine radical signal. Polymerization of hemoglobin and aggregation of the erythrocytes were observed. On the other hand, normal erythrocytes exhibited only mild hemolysis by the addition of hydrogen peroxide under similar conditions. From these results, the scavenging of hydrogen peroxide by hemoglobin generates the ferryl hemoglobin species (H-Hb-Fe(IV)=O) plus protein-based radicals (*Hb-Fe(IV)=O). These species induce hemolysis of erythrocytes, polymerization of hemoglobin, and aggregation of the acatalasemic erythrocytes. A mechanism for the onset of Takarara disease is proposed.  相似文献   
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Climate changes on various time scales often shape genetic novelty and adaptive variation in many biotas. We explored molecular signatures of directional selection in populations of the ice goby Leucopsarion petersii inhabiting a unique sea basin, the Sea of Japan, where a wide variety of environments existed in the Pleistocene in relation to shifts in sea level by repeated glaciations. This species consisted of two historically allopatric lineages, the Japan Sea (JS) and Pacific Ocean (PO) lineages, and these have lived under contrasting marine environments that are expected to have imposed different selection regimes caused by past climatic and current oceanographic factors. We applied a limited genome‐scan approach using seven candidate genes for phenotypic differences between two lineages in combination with 100 anonymous microsatellite loci. Neuropeptide Y (NPY) gene, which is an important regulator of food intake and potent orexigenic agent, and three anonymous microsatellites were identified as robust outliers, that is, candidate loci potentially under directional selection, by multiple divergence‐ and diversity‐based outlier tests in comparisons focused on multiple populations of the JS vs. PO lineages. For these outlier loci, populations of the JS lineage had putative signals of selective sweeps. Additionally, real‐time quantitative PCR analysis using fish reared in a common environment showed a higher expression level for NPY gene in the JS lineage. Thus, this study succeeded in identifying candidate genomic regions under selection across populations of the JS lineage and provided evidence for lineage‐specific adaptive evolution in this unique sea basin.  相似文献   
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