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31.
The injurious effect of pisatin on the plasma membrane of pea   总被引:4,自引:0,他引:4  
The main cause of wilting which occurs in pea leaves heavilyinfected with powdery mildew was suggested to be due to theinjurious effect of pisatin, a defensive antifungal substanceproduced by the host leaves, which affects the plasma membraneof the same host cells. (Received May 29, 1975; )  相似文献   
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Many decapod crustaceans in marine intertidal habitats release larvae toward coastal oceans, from which postlarvae (decapodids: settling-stage larvae) return home. Decapodid settlement processes are poorly understood. Previous studies showed that in Kyushu, Japan, the callianassid shrimp population on an intertidal sandflat of an open bay joining the coastal ocean near a large estuary released eight batches of larvae basically in a semilunar cycle from June through October and that decapodids performed diel vertical migration, occurring in the water column nocturnally. We conducted (a) frequent sampling for population density and size-composition on the sandflat through one reproductive season, (b) planktonic and benthic sampling for decapodids around the bay mouth, and (c) current meter deployment at three points across the bay mouth for tidal harmonic analysis. On the sandflat, six batches of newly-settled decapodids (settlers) occurred in a semilunar periodicity until October, with peaks occurring 0–3 days before syzygy dates except for the first one. For larval Batches 1–4, buoyancy-driven shoreward subsurface currents during July to mid-October would transport some pre-decapodid-stage larvae (zoeae) toward the bay. The absence of expected settler Batches 7–8 would be due to the converse subsurface currents caused by water-column mixing and seasonal winds after mid-October, carrying zoeae offshore. Once in the bay, phasing of night and nighttime-averaged shoreward tidal current explained the settlement pattern for Batches 1–4. For Batches 5–6 occurring in mid-September to mid-October, water currents generated by seasonal wind and tidal forcings may have caused peak settlement after the time expected from tidally-driven decapodid transport.  相似文献   
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The activation process of secretory or membrane-bound zinc enzymes is thought to be a highly coordinated process involving zinc transport, trafficking, transfer and coordination. We have previously shown that secretory and membrane-bound zinc enzymes are activated in the early secretory pathway (ESP) via zinc-loading by the zinc transporter 5 (ZnT5)-ZnT6 hetero-complex and ZnT7 homo-complex (zinc transport complexes). However, how other proteins conducting zinc metabolism affect the activation of these enzymes remains unknown. Here, we investigated this issue by disruption and re-expression of genes known to be involved in cytoplasmic zinc metabolism, using a zinc enzyme, tissue non-specific alkaline phosphatase (TNAP), as a reporter. We found that TNAP activity was significantly reduced in cells deficient in ZnT1, Metallothionein (MT) and ZnT4 genes (ZnT1 −/− MT −/− ZnT4 −/− cells), in spite of increased cytosolic zinc levels. The reduced TNAP activity in ZnT1 −/− MT −/− ZnT4 −/− cells was not restored when cytosolic zinc levels were normalized to levels comparable with those of wild-type cells, but was reversely restored by extreme zinc supplementation via zinc-loading by the zinc transport complexes. Moreover, the reduced TNAP activity was adequately restored by re-expression of mammalian counterparts of ZnT1, MT and ZnT4, but not by zinc transport-incompetent mutants of ZnT1 and ZnT4. In ZnT1 −/− MT −/− ZnT4 −/− cells, the secretory pathway normally operates. These findings suggest that cooperative zinc handling of ZnT1, MT and ZnT4 in the cytoplasm is required for full activation of TNAP in the ESP, and present clear evidence that the activation process of zinc enzymes is elaborately controlled.  相似文献   
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Abstract

Research involving differentiated embryonic stem (ES) cells may revolutionize the study of liver disease, improve the drug discovery process, and assist in the development of stem-cell-based clinical therapies. Generation of ES cell-derived hepatic tissue has benefited from an understanding of the cytokines, growth factors and biochemical compounds that are essential in liver development, and this knowledge has been used to mimic some aspects of embryonic development in vitro. Although great progress has been made in differentiating human ES cells into liver cells, current protocols have not yet produced cells with the phenotype of a mature hepatocyte. There is a of disease models have been examined concerning whether stem cells can correct liver disease. It is a bit premature to conclude that hepatocytes can be generated from non-hepatic cells in culture that will be clinically useful. Standard criteria will need to be developed to assess the extent to which human stem cell-derived hepatocytes have been produced.  相似文献   
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Acute inflammation is a prominent feature of central nervous system (CNS) insult and is detrimental to the CNS tissue. Although this reaction spontaneously diminishes within a short period of time, the mechanism underlying this inflammatory resolution remains largely unknown. In this study, we demonstrated that an initial infiltration of Ly6C+Ly6G? immature monocyte fraction exhibited the same characteristics as myeloid‐derived suppressor cells (MDSCs), and played a critical role in the resolution of acute inflammation and in the subsequent tissue repair by using mice spinal cord injury (SCI) model. Complete depletion of Ly6C+Ly6G? fraction prior to injury by anti‐Gr‐1 antibody (clone: RB6‐8C5) treatment significantly exacerbated tissue edema, vessel permeability, and hemorrhage, causing impaired neurological outcomes. Functional recovery was barely impaired when infiltration was allowed for the initial 24 h after injury, suggesting that MDSC infiltration at an early phase is critical to improve the neurological outcome. Moreover, intraspinal transplantation of ex vivo‐generated MDSCs at sites of SCI significantly reduced inflammation and promoted tissue regeneration, resulting in better functional recovery. Our findings reveal the crucial role of an Ly6C+Ly6G? fraction as MDSCs in regulating inflammation and tissue repair after SCI, and also suggests an MDSC‐based strategy that can be applied to acute inflammatory diseases.  相似文献   
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