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941.
Phylogenetic relastionships within the family pomacentridae teleostei: Perciformes) were inferred by analyzing a portion of the 12S mitochondrial ribosomal DNA gene. Thirty-four pomacentrid species were sequenced for this study and the resulting data were combined with previously published pomacentrid sequence data to form a combined matrix of 53 pomacentrids representing 48 different species in 18 genera. Four outgroup species were also drawn from published data; these taxa were taken from the other three putative families of the suborder Labroidei, as well as a single representative of the family Moronidae. The data set contained 1053 data columns after alignment according to ribosomal secondary structure and the removal of all ambiguously aligned positions. The resulting strict consensus tree topology generally agreed with the previous molecular hypothesis, and recovers a monophyletic Pomacentridae and subfamily Amphiprioninae. The two other subfamilies included, Chrominae and Pomacentrinae, were found to be polyphyletic. A monophyletic group consisting of the Amphiprioninae, Pomacentrus, Acanthochromis, Amblyglyphidodon, Neoglyphidodon, Chrysiptera, Neopomacentrus, and Teixeirichthys was found. This group was recovered as the sister group to a clade consisting of a paraphyletic Chromis and a monophyletic Dascyllus. A sister-group relationship between the genus Pomacentrus and the subfamily Amphiprioninae was observed. 相似文献
942.
The localization of the integral membrane protein Cps1p to the cell division site is dependent on the actomyosin ring and the septation-inducing network in Schizosaccharomyces pombe 下载免费PDF全文
Liu J Tang X Wang H Oliferenko S Balasubramanian MK 《Molecular biology of the cell》2002,13(3):989-1000
Schizosaccharomyces pombe cells divide by medial fission through the use of an actomyosin-based contractile ring. Constriction of the actomyosin ring is accompanied by the centripetal addition of new membranes and cell wall material. In this article, we characterize the mechanism responsible for the localization of Cps1p, a septum-synthesizing 1,3-beta-glucan synthase, to the division site during cytokinesis. We show that Cps1p is an integral membrane protein that localizes to the cell division site late in anaphase. Neither F-actin nor microtubules are essential for the initial assembly of Cps1p to the medial division site. F-actin, but not microtubules, is however important for the eventual incorporation of Cps1p into the actomyosin ring. Assembly of Cps1p into the cell division ring is also dependent on the septation-inducing network (SIN) proteins that regulate division septum formation after assembly of the actomyosin ring. Fluorescence-recovery after-photobleaching experiments reveal that Cps1p does not diffuse appreciably within the plasma membrane and is retained at the division site by a mechanism that does not depend on an intact F-actin cytoskeleton. We conclude that the actomyosin ring serves as a spatial cue for Cps1p localization, whereas the maintenance of Cps1p at the division site occurs by a novel F-actin- and microtubule-independent mechanism. Furthermore, we propose that the SIN proteins ensure localization of Cps1p at the appropriate point in the cell cycle. 相似文献
943.
944.
945.
Kim HU Cotter R Johnson S Senda M Dodds P Kulikauska R Tang W Ezcura I Herzmark P McCormick S 《Plant molecular biology》2002,50(1):1-16
We previously characterized LePRK1 and LePRK2, pollen-specific receptor kinases from tomato (Muschietti et al., 1998). Here we identify a similar receptor kinase from maize, ZmPRK1, that is also specifically expressed late in pollen development, and a third pollen receptor kinase from tomato, LePRK3. LePRK3 is less similar to LePRK1 and LePRK2 than either is to each other. We used immunolocalization to show that all three LePRKs localize to the pollen tube wall, in partially overlapping but distinct patterns. We used RT-PCR and degenerate primers to clone homologues of the tomato kinases from other Solanaceae. We deduced features diagnostic of pollen receptor kinases and used these criteria to identify family members in the Arabidopsis database. RT-PCR confirmed pollen expression for five of these Arabidopsis candidates; two of these are clearly homologues of LePRK3. Our results reveal the existence of a distinct pollen-specific receptor kinase gene family whose members are likely to be involved in perceiving extracellular cues during pollen tube growth. 相似文献
946.
Low sequence variation among isolates of infectious hypodermal and hematopoietic necrosis virus (IHHNV) originating from Hawaii and the Americas 总被引:2,自引:0,他引:2
A 2.9 kb fragment of the infectious hypodermal and hematopoietic necrosis virus (IHHNV) genome, which contains the coding sequence of putative non-structural and capsid proteins, was amplified and sequenced from each of 14 IHHNV isolates collected from cultured penaeid shrimp stocks in Hawaii and various sites in the Americas between 1982 and 1997. The sequence comparison indicates that the IHHNV genome is very stable, with 99.6 to 100% similarity among these 14 isolates. Only nucleotide substitutions were found. The percentage of substitution was higher in the putative capsid proteins region (1.3%) than in the putative non-structural proteins region (0.6%). Out of 25 substitutions found, 14 resulted in amino acid changes. There is no apparent association between clinical outcomes and particular amino acid substitutions. Based on genetic distances, the isolates were clustered into 3 groups that generally correspond with their geographic origins. 相似文献
947.
Effects of different peptide fragments derived from proadrenomedullin on gene expression of adrenomedullin gene 总被引:28,自引:0,他引:28
Primary culture of vascular smooth muscle cells (VSMC) from rat aorta was used for the study of the effect of different peptides derived from proadrenomedullin on the expression of adrenomedullin (ADM) gene. ADM and preproADM(22-41) (PAMP) secreted by VSMC were measured by radioimmunoassay, and ADM mRNA in VSMC was determined by quantitative RT-PCR. After the incubation of VSMC in 10(-7)M ADM for 24h, PAMP in the medium and ADM mRNA in the VSMC were decreased by 34 and 41.3%, respectively, and cAMP concentration in the VSMC was increased by 385%. After the incubation of VSMC in 10(-7)M PAMP for 24h, ADM in the medium and ADM mRNA in the VSMC were decreased by 12.2 and 39.1%, respectively, and cAMP concentration in the VSMC was increased by 67%. The decreased ADM mRNA in VSMC induced by the ADM and PAMP treatment was completely reversed by the pre-treatment of the cells in 10(-7)M protein kinase inhibitor for 30 min. After the incubation of VSMC in 10(-7)M preproADM(153-185) (ADT) for 24h, however, ADM in the medium and ADM mRNA in the VSMC were increased by 21 and 35.2%. The increased ADM mRNA in VSMC induced by the ADT treatment was partially blocked by the co-incubation in ADM and ADT, and was totally blocked by the co-incubation in PAMP+ADM and ADT, but was not blocked by the co-incubation in PAMP and ADT. Our results suggest that the four peptides derived from proadrenomedullin may have different effects, possibly through a cAMP-dependent pathway, on the expression of ADM gene. 相似文献
948.
Green fluorescent protein (GFP) gene was transfected and expressed in murine embryonic stem (ES) cells under the control of the astrocyte-specific glial fibrillary acidic protein (GFAP) promoter. Stably transfected cells were characterized by immunohistochemistry and by fluorescence microscopy. Cells containing GFP were differentiated to Type I and Type II astrocytes after induction by all-trans retinoic acid. Differentiated cells were expressed GFP and visualized by fluorescence microscopy. Differentiated cells expressed GFP were correlated with the expression of GFAP and morphological change. It demonstrates that the cell line expressed GFP can be used to trace the morphological changes of astrocytes during differentiation, and further for the isolation of astrocytes from the mixed cells differentiated from ES cell. 相似文献
949.
Nitric oxide decreases the sensitivity of pulmonary endothelial cells to LPS-induced apoptosis in a zinc-dependent fashion 总被引:1,自引:0,他引:1
Tang Zi-Lue Wasserloos Karla J. Liu Xianghong Stitt Molly S. Reynolds Ian J. Pitt Bruce R. St. Croix Claudette M. 《Molecular and cellular biochemistry》2002,(1):211-217
We hypothesized that: (a) S-nitrosylation of metallothionein (MT) is a component of pulmonary endothelial cell nitric oxide (NO) signaling that is associated with an increase in labile zinc; and (b) NO mediated increases in labile zinc in turn reduce the sensitivity of pulmonary endothelium to LPS-induced apoptosis. We used microspectrofluorometric techniques to show that exposing mouse lung endothelial cells (MLEC) to the NO-donor, S-nitrosocysteine, resulted in a 45% increase in fluorescence of the Zn2+-specific fluorophore, Zinquin, that was rapidly reversed by exposure to the Zn2+ chelator, NNNN-tetrakis-(2-pyridylmethyl)ethylenediamine; TPEN). The absence of a NO-mediated increase in labile Zn2+ in MLEC from MT-I and -II knockout mice inferred a critical role for MT in the regulation of Zn2+ homeostasis by NO. Furthermore, we found that prior exposure of cultured endothelial cells from sheep pulmonary artery (SPAEC), to the NO-donor, S-nitroso-N-acetylpenicillamine (SNAP) reduced their sensitivity to lipopolysaccharide (LPS) induced apoptosis. The anti-apoptotic effects of NO were significantly inhibited by Zn2+ chelation with low doses of TPEN (10 M). Collectively, these data suggest that S-nitrosylation of MT is associated with an increase in labile (TPEN chelatable) zinc and NO-mediated MT dependent zinc release is associated with reduced sensitivity to LPS-induced apoptosis in pulmonary endothelium. 相似文献
950.
Nitrate uptake,nitrate reductase distribution and their relation to proton release in five nodulated grain legumes 总被引:4,自引:0,他引:4
Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0.2 and 2 mM nitrate in nutrient solution. Nitrate treatments, imposed on 22-d-old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0.2 mM nitrate supply, nitrate uptake rates ranged from 0.6 to 1.5 mg N g(-1) d(-1) in the order: yellow lupin > field pea (Pisum sativum) > chickpea (Cicer arietinum) > narrow-leafed lupin (L angustifolius) > white lupin (L albus). At 2 mM nitrate supply, nitrate uptake ranged from 1.7 to 8.2 mg N g(-1) d(-1) in the order: field pea > chickpea > white lupin > yellow lupin > narrow-leafed lupin. Nitrate reductase activity increased with increased nitrate supply, with the majority of NRA being present in shoots. Field pea and chickpea had much higher shoot NRA than the three lupin species. When 0.2 mM nitrate was supplied, narrow-leafed lupinreleased the most H+ per unit root biomass per day, followed by yellow lupin, white lupin, field pea and chickpea. At 2 mM nitrate, narrow-leafed lupin and yellow lupin showed net proton release, whereas the other species, especially field pea, showed net OH- release. Irrespective of legume species and nitrate supply, proton release was negatively correlated with nitrate uptake and NRA in shoots, but not with NRA in roots. 相似文献