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971.
Maeshima Masayoshi; Nakayasu Tsuyoshi; Kawauchi Keiko; Hirata Hajime; Shimmen Teruo 《Plant & cell physiology》1999,40(4):439-442
Cycloprodigiosin hydrochloride (cPrG-HCl) at 10 nM uncoupledboth H+-ATPase and H+-translocating pyrophosphatase in vacuolarmembrane vesicles of mung bean, but did not inhibit the substratehydrolysis. cPrG-HCl destroyed the transmembrane pH gradientonly in the presence of Cl. The observations indicatethat cPrG-HCl functions as a H+/Cl symporter. Vesicleacidification was restored by SO24 even in the presenceof cPrG-HCl. (Received November 13, 1998; Accepted January 21, 1999) 相似文献
972.
T Hamano S Murakami K Takayama S Ehira K Maruyama H Kawakami E H Morita H Hayashi N Sato 《Cellular and molecular biology, including cyto-enzymology》2004,50(5):613-624
The Rbp proteins in cyanobacteria are RNA-binding proteins with a single RNA recognition motif or RRM. A comprehensive assembly of genomic data suggests that there are two major classes of Rbp proteins (classes I and II) that diverged before the diversification of cyanobacteria. Class I proteins are further classified into two types with or without a C-terminal glycine-rich domain. The results of selection from a random RNA pool suggest that RbpA1 (class I) has affinity to C-rich and G-rich sequences. In vitro RNA binding assay with homopolymers indicated that class II protein has low affinity to poly(G) in contrast with class I proteins. Site-specific mutagenesis analysis of the RRM in RbpA1 showed that the aromatic residues Tyr4 or Phe46 are important in RNA binding as well as maintenance of secondary structure. We also tested various truncated proteins lacking the C-terminal domain as well as point mutants. Most of these proteins exhibited decreased affinity to RNA. Circular dichroism analysis as well as chromatographic analysis showed that Tyr4 and Phe46 are also important in maintaining the structure of RbpA1 protein. The C-terminal glycine-rich domain itself does not contribute much to the RNA-binding, but Arg83 which is located close to the C-terminal end of RRM is important in the RNA-binding. 相似文献
973.
Land use change emission scenarios: anticipating a forest transition process in the Brazilian Amazon 总被引:1,自引:0,他引:1
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Ana Paula Dutra Aguiar Ima Célia Guimarães Vieira Talita Oliveira Assis Eloi L Dalla‐Nora Peter Mann Toledo Roberto Araújo Oliveira Santos‐Junior Mateus Batistella Andrea Santos Coelho Elza Kawakami Savaget Luiz Eduardo Oliveira Cruz Aragão Carlos Afonso Nobre Jean Pierre H. Ometto 《Global Change Biology》2016,22(5):1821-1840
Following an intense occupation process that was initiated in the 1960s, deforestation rates in the Brazilian Amazon have decreased significantly since 2004, stabilizing around 6000 km2 yr?1 in the last 5 years. A convergence of conditions contributed to this, including the creation of protected areas, the use of effective monitoring systems, and credit restriction mechanisms. Nevertheless, other threats remain, including the rapidly expanding global markets for agricultural commodities, large‐scale transportation and energy infrastructure projects, and weak institutions. We propose three updated qualitative and quantitative land‐use scenarios for the Brazilian Amazon, including a normative ‘Sustainability’ scenario in which we envision major socio‐economic, institutional, and environmental achievements in the region. We developed an innovative spatially explicit modelling approach capable of representing alternative pathways of the clear‐cut deforestation, secondary vegetation dynamics, and the old‐growth forest degradation. We use the computational models to estimate net deforestation‐driven carbon emissions for the different scenarios. The region would become a sink of carbon after 2020 in a scenario of residual deforestation (~1000 km2 yr?1) and a change in the current dynamics of the secondary vegetation – in a forest transition scenario. However, our results also show that the continuation of the current situation of relatively low deforestation rates and short life cycle of the secondary vegetation would maintain the region as a source of CO2 – even if a large portion of the deforested area is covered by secondary vegetation. In relation to the old‐growth forest degradation process, we estimated average gross emission corresponding to 47% of the clear‐cut deforestation from 2007 to 2013 (using the DEGRAD system data), although the aggregate effects of the postdisturbance regeneration can partially offset these emissions. Both processes (secondary vegetation and forest degradation) need to be better understood as they potentially will play a decisive role in the future regional carbon balance. 相似文献
974.
Distinct roles of the two VPS33 proteins in the endolysosomal system in Caenorhabditis elegans
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Keiko Gengyo‐Ando Eriko Kage‐Nakadai Sawako Yoshina Muneyoshi Otori Yuko Kagawa‐Nagamura Junichi Nakai Shohei Mitani 《Traffic (Copenhagen, Denmark)》2016,17(11):1197-1213
Sec1/Munc‐18 (SM) family proteins are essential regulators in intracellular transport in eukaryotic cells. The SM protein Vps33 functions as a core subunit of two tethering complexes, class C core vacuole/endosome tethering (CORVET) and homotypic fusion and vacuole protein sorting (HOPS) in the endocytic pathway in yeast. Metazoan cells possess two Vps33 proteins, VPS33A and VPS33B, but their precise roles remain unknown. Here, we present a comparative analysis of Caenorhabditis elegans null mutants for these proteins. We found that the vps‐33.1 (VPS33A) mutants exhibited severe defects in both endocytic function and endolysosomal biogenesis in scavenger cells. Furthermore, vps‐33.1 mutations caused endocytosis defects in other tissues, and the loss of maternal and zygotic VPS‐33.1 resulted in embryonic lethality. By contrast, vps‐33.2 mutants were viable but sterile, with terminally arrested spermatocytes. The spermatogenesis phenotype suggests that VPS33.2 is involved in the formation of a sperm‐specific organelle. The endocytosis defect in the vps‐33.1 mutant was not restored by the expression of VPS‐33.2, which indicates that these proteins have nonredundant functions. Together, our data suggest that VPS‐33.1 shares most of the general functions of yeast Vps33 in terms of tethering complexes in the endolysosomal system, whereas VPS‐33.2 has tissue/organelle specific functions in C. elegans. 相似文献
975.
976.
Wakana Azuma H. Roaki Ishii Katsushi Kuroda Keiko Kuroda 《Trees - Structure and Function》2016,30(1):141-152
Key message
In Cryptomeria japonica , transfusion tissue in leaves may have functions of water storage and supply, which could compensate for hydraulic constraints with increasing height.Abstract
The tallest trees of Cryptomeria japonica occur in climatic regions similar to the world’s tallest trees. We hypothesized that tall C. japonica trees would have evolved adaptive mechanisms to overcome height growth limitation. Here, we focused on foliar water storage, a mechanism recently discovered in Sequoia sempervirens. In C. japonica, leaf water potential at turgor loss did not change with height or light availability, while leaf hydraulic capacitance and succulence (water content per leaf surface area) increased, suggesting hydraulic compensation. Plasticity of leaf morphology could contribute to avoiding negative effects of height on photosynthesis. We also focused on the structure and function of transfusion tissue in leaves and its role in water storage and supply. Cross-sectional area of transfusion tissue increased with height, whereas that of xylem was constant. We confirmed that water flowed from vascular bundle to mesophyll via the transfusion tissue. Cryo-scanning electron microscopy images of leaf cross sections showed that transfusion cells were flattened, but not fully dehydrated when leaf water potential decreased in situ and by experimental dehydration, and cell deformation was more marked for treetop leaves than for lower-crown leaves. The shape of transfusion cells recovered at predawn as well as after experimental rehydration. As in S. sempervirens, transfusion tissue of C. japonica may function as a hydraulic buffer, absorbing and releasing water according to leaf water status. Anatomical and hydraulic properties contributing to foliar water storage may be an adaptive mechanism acquired by tall Cupressaceae trees to overcome the hydraulic constraints on physiological function with increasing height.977.
Takamasa Mizoguchi Koichi Kawakami Motoyuki Itoh 《Genesis (New York, N.Y. : 2000)》2016,54(9):483-489
Actin filaments and microtubules are principal components of the cytoskeleton that regulate the basic cellular phenomena underlying many fundamental cellular processes. Therefore, analyzing their dynamics in living cells is important for understanding cellular events more precisely. In this article, we report two novel transgenic zebrafish lines expressing red fluorescent proteins tagged with Lifeact or EB1 that interact with actin filaments and microtubule plus ends, respectively, under the control of the GAL4‐UAS system. Using these transgenic lines, we could detect F‐actin and microtubule plus end dynamics in specific tissues of living zebrafish embryos by crossing with GAL4 driver lines. In addition, we could achieve multi‐color imaging using these transgenic lines with GFP‐expressing transgenic lines. Therefore, our transgenic lines that carry UAS‐driven red fluorescent cytoskeletal probes are useful tools for analyzing spatiotemporal changes of the cytoskeletal elements using multicolor live imaging. 相似文献
978.
Yuria?Saito Kiyo-aki?Ishii Yuichi?Aita Tatsuhiko?Ikeda Yasushi?Kawakami Hitoshi?Shimano Hisato?Hara Kazuhiro?TakekoshiEmail author 《Neurochemical research》2016,41(4):696-706
Germline mutations in genes encoding succinate dehydrogenase subunits are associated with the development of familial pheochromocytomas and paragangliomas [hereditary paraganglioma/pheochromocytoma syndrome (HPPS)]. In particular, a mutation in succinate dehydrogenase subunit B (SDHB) is highly associated with abdominal paraganglioma and subsequent distant metastasis (malignant paraganglioma), indicating the importance of SDHB genetic testing. The discovery of HPPS suggests an association among genetic mitochondrial defects, tumor development, and catecholamine oversecretion. To investigate this association, we transfected pheochromocytoma cells (PC12) with SDHB-specific siRNA. SDHB silencing virtually abolished complex II activity, demonstrating the utility of this in vitro model for investigating the pseudo-hypoxic drive hypothesis. Lack of complex II activity resulting from RNA interference of SDHB increased tyrosine hydroxylase (TH; the rate-limiting enzyme in catecholamine biosynthesis) activity and catecholamine secretion. Reduced apoptosis was observed accompanied by Bcl-2 accumulation in PC12 cells, consistent with the phenotypes of paragangliomas with SDHB mutations. In addition, SDHB silencing increased reactive oxygen species (ROS) production and nuclear HIF1α stabilization under normoxic conditions. Furthermore, phenotypes induced by complex II activity knockdown were abolished by pretreatment with N-acetyl cysteine (an ROS scavenger) and by prior HIF1α knockdown, indicating an ROS- and HIF1α-dependent mechanism. Our results indicate that increased ROS may act as signal transduction messengers that induce HIF1α stabilization and may be necessary for the pseudo-hypoxic states observed in our experimental model. To our knowledge, this is the first study demonstrating that pseudo-hypoxic states resulting from SDHB knockdown are associated with increased TH activity and catecholamine oversecretion. 相似文献
979.
Nuclear extrusion precedes discharge of genomic DNA fibers during tunicamycin‐induced neutrophil extracellular trap‐osis (NETosis)‐like cell death in cultured human leukemia cells
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980.