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991.
Thiago C. Mendes Juan P. Quimbayo Helena F. Bouth Luana P.S. Silva Carlos E.L. Ferreira 《Journal of fish biology》2019,95(3):812-819
This study evaluated the functional role of the highly generalist omnivore Melichthys niger in the remote St. Peter and St Paul's Archipelago (SPSPA), Brazil, where grazing herbivorous fishes are very scarce. We analysed patterns of distribution from zero to 30 m deep during three time intervals during the day and sampled different aspects of their feeding behaviour, including diel feeding rate, feeding substrate and diet. The density of M. niger increased with depth (26–30 m) and decreased by the end of the day. Although M. niger did not present a typical herbivore diel feeding pattern, they targeted the epilithic algal matrix as their primary feeding substrate, ingesting predominantly algae and detritus. The characteristic Caulerpa racemosa var. peltata from SPSPA was ingested only as detached fronds. We suggest that in the isolated SPSPA, the single species M. niger may perform a unique role as a link between benthic primary production and higher levels. Further studies on the trophic ecology of omnivorous species are necessary to better understand their roles in a reef system, especially in impoverished areas where they are likely to play a crucial role. 相似文献
992.
Pedro Cisternas Juan M. Zolezzi Milka Martinez Viviana I. Torres Guang William Wong Nibaldo C. Inestrosa 《Journal of neurochemistry》2019,149(1):54-72
Dysregulated Wnt signaling is linked to major neurodegenerative diseases, including Alzheimer disease (AD). In mouse models of AD, activation of the canonical Wnt signaling pathway improves learning/memory, but the mechanism for this remains unclear. The decline in brain function in AD patients correlates with reduced glucose utilization by neurons. Here, we test whether improvements in glucose metabolism mediate the neuroprotective effects of Wnt in AD mouse model. APPswe/PS1dE9 transgenic mice were used to model AD, Andrographolide or Lithium was used to activate Wnt signaling, and cytochalasin B was used to block glucose uptake. Cognitive function was assessed by novel object recognition and memory flexibility tests. Glucose uptake and the glycolytic rate were determined using radiotracer glucose. The activities of key enzymes of glycolysis such as hexokinase and phosphofructokinase, Adenosine triphosphate (ATP)/Adenosine diphosphate (ADP) levels and the pentose phosphate pathway and activity of glucose‐6 phosphate dehydrogenase were measured. Wnt activators significantly improved brain glucose utilization and cognitive performance in transgenic mice. Wnt signaling enhanced glucose metabolism by increasing the expression and/or activity of hexokinase, phosphofructokinase and AMP‐activated protein kinase. Inhibiting glucose uptake partially abolished the beneficial effects of Wnt signaling on learning/memory. Wnt activation also enhanced glucose metabolism in cortical and hippocampal neurons, as well as brain slices derived from APPswe/PS1E9 transgenic mice. Combined, these data provide evidence that the neuroprotective effects of Wnt signaling in AD mouse models result, at least in part, from Wnt‐mediated improvements in neuronal glucose metabolism. 相似文献
993.
Qiang‐Qiang Xiong Tian‐Hua Shen Lei Zhong Chang‐Lan Zhu Xiao‐Song Peng Xiao‐Peng He Jun‐Ru Fu Lin‐Juan Ouyang Jian‐Min Bian Li‐Fang Hu Xiao‐Tang Sun Jie Xu Hui‐Ying Zhou Hao‐Hua He Xiao‐Rong Chen 《Physiologia plantarum》2019,167(4):564-584
Abrupt drought–flood alternation (T1) is a meteorological disaster that frequently occurs during summer in southern China and the Yangtze river basin, often causing a significant loss of rice production. In this study, the response mechanism of yield decline under abrupt drought–flood alternation stress at the panicle differentiation stage was analyzed by looking at the metabolome, proteome as well as yield and physiological and biochemical indexes. The results showed that drought and flood stress caused a decrease in the yield of rice at the panicle differentiation stage, and abrupt drought–flood alternation stress created a synergistic effect for the reduction of yield. The main reason for the decrease of yield per plant under abrupt drought–flood alternation was the decrease of seed setting rate. Compared with CK0 (no drought and no flood), the net photosynthetic rate and soluble sugar content of T1 decreased significantly and its hydrogen peroxidase, superoxide dismutase, peroxidase activity increased significantly. The identified differential metabolites and differentially expressed proteins indicated that photosynthesis metabolism, energy metabolism pathway and reactive oxygen species response have changed strongly under abrupt drought–flood alteration stress, which are factors that leads to the rice grain yield reduction. 相似文献
994.
Alberto De Jesús-Navarrete Frank Alberto Ocaña-Borrego José Juan Oliva-Rivera Rosa María De Jesús-Carrillo Abel Abraham Vargas-Espositos 《Studies on Neotropical Fauna and Environment》2019,54(1):1-9
Pomacea flagellata is a gastropod conspicuous in freshwater environments, and represents a fishing resource. To assess their abundance, distribution, and secondary production, monthly samplings were carried out in Bacalar Lake from June 2012 to May 2013 at 12 sampling sites. In each site, three random transects were marked parallel to the shore. All snails on transect were collected and shell length and wet weight measured. The highest density occurred in September (1.27 ind.m?2), lowest in October (0.47 ind.m?2). Shell lengths ranged from 2 to 56 mm, with recruitment in January–March. Growth parameters were L∞ 59.50 mm, K 0.65.year?1; the lifetime span was 3 years. Average biomass reached 5.57 wet g.m?2 and secondary production was 6.025 wet g.m?2.year-1; annual renewal rate P/B 1.08. Highest abundance and secondary production was contributed by individuals between 31 and 41 mm in length. A potential biomass of 25.06 tons of snails was estimated in the lake. Snail densities, secondary production, and turnover were very low during the year, indicating that it is not viable to consider a commercial catch without affecting the population. A ban of 10 years is proposed, and aquaculture practices of snails are recommended to recover the resource. 相似文献
995.
Jon Ochoa Adrin Valli Mar Martín‐Trillo Carmen Simn‐Mateo Juan Antonio García Bernardo Rodamilans 《Plant, cell & environment》2019,42(11):3015-3026
Plants use RNA silencing as a strong defensive barrier against virus challenges, and viruses counteract this defence by using RNA silencing suppressors (RSSs). With the objective of identifying host factors helping either the plant or the virus in this interaction, we have performed a yeast two‐hybrid screen using P1b, the RSS protein of the ipomovirus Cucumber vein yellowing virus (CVYV, family Potyviridae), as a bait. The C‐8 sterol isomerase HYDRA1 (HYD1), an enzyme involved in isoprenoid biosynthesis and cell membrane biology, and required for RNA silencing, was isolated in this screen. The interaction between CVYV P1b and HYD1 was confirmed in planta by Bimolecular Fluorescence Complementation assays. We demonstrated that HYD1 negatively impacts the accumulation of CVYV P1b in an agroinfiltration assay. Moreover, expression of HYD1 inhibited the infection of the potyvirus Plum pox virus, especially when antiviral RNA silencing was boosted by high temperature or by coexpression of homologous sequences. Our results reinforce previous evidence highlighting the relevance of particular composition and structure of cellular membranes for RNA silencing and viral infection. We report a new interaction of an RSS protein from the Potyviridae family with a member of the isoprenoid biosynthetic pathway. 相似文献
996.
Reyes-Martínez Antonio Valle-Aguilera Juan Roberto Antunes-Ricardo Marilena Gutiérrez-Uribe Janet Gonzalez Carmen Santos-Díaz María del Socorro 《Plant Cell, Tissue and Organ Culture》2019,139(1):119-129
Plant Cell, Tissue and Organ Culture (PCTOC) - Pyrostegia venusta (Ker Gawl.) Miers is a plant used for the treatment of respiratory diseases, diarrhea, vitiligo, jaundice and to attenuate... 相似文献
997.
998.
999.
Lavado Nieves de la Concepción Juan García Babiano Reyes Cintas Pedro Light Mark E. 《Origins of life and evolution of the biosphere》2019,49(3):163-185
Origins of Life and Evolution of Biospheres - In line with the postulated intermediacy of aminoxazoles derived from small sugars toward the direct assembly of nucleoside precursors, we show here a... 相似文献
1000.