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排序方式: 共有599条查询结果,搜索用时 82 毫秒
591.
Flora Mok 《Journal of experimental marine biology and ecology》2008,357(2):99-108
Although newly described, Pseudopolydora vexillosa is one of the most conspicuous surface-feeding spioniform polychaetes in subtropical waters. This is the first report on larval growth and metamorphosis of P. vexillosa. Newly hatched (3-chaetigers stage) larvae of P. vexillosa reached metamorphic competence at 12-17 chaetigers stage when fed with Chaetoceros gracilis or Dunaliella tertiolecta at a concentration of ∼ 105 cells ml− 1 for 6 to 8 days at 32 psu and 27 °C. Larvae on these two diets achieved comparable levels, of approximately 70% metamorphosis. On the other hand, larvae fed with Isochrysis galbana or starved in 0.22 μm filtered seawater never reached competence during the 10 days of study. The effect of organic matter on larval substrate selection was examined using glass beads, manipulated sediments and natural sediments. A significantly higher percentage of larvae metamorphosed on glass beads that had been submerged in unfiltered natural seawater for 5 days as compared to the control; when manipulating the organic content of sediment as a substratum, significantly more larvae metamorphosed in 100% natural sediment, compared with 0%, 25%, 50%, and 75% natural sediment mixed with different portions of ashed sediment. Surprisingly, with natural undisturbed surface sediment sampled along a transect perpendicular to a sewage discharge site, these laboratory bioassays demonstrate that the larvae of P. vexillosa are capable of responding to sedimentary cues in complex ways to find a habitat suitable for metamorphosis and survival. 相似文献
592.
A significant effort is made by the cell to maintain certain phospholipids at specific sites. It is well described that proteins involved in intracellular signaling can be targeted to the plasma membrane and organelles through phospholipid-binding domains. Thus, the accumulation of a specific combination of phospholipids, denoted here as the ‘phospholipid code'', is key in initiating cellular processes. Interestingly, a variety of extracellular proteins and pathogen-derived proteins can also recognize or modify phospholipids to facilitate the recognition of dying cells, tumorigenesis and host–microbe interactions. In this article, we discuss the importance of the phospholipid code in a range of physiological and pathological processes. 相似文献
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Cheng Han Ng Snow Yunni Lin Yip Han Chin Ming Hui Lee Nicholas Syn Xin Lei Goh Jin Hean Koh Jingxuan Quek Darren Jun Hao Tan Shao Feng Mok Eunice Tan Yock Young Dan Nicholas Chew Chin Meng Khoo Mohammad Shadab Siddiqui Mark Muthiah 《Endocrine practice》2022,28(2):223-230
ObjectiveType 2 diabetes mellitus and nonalcoholic fatty liver disease (NAFLD) are closely related, and antidiabetic medications have been shown to be potential therapeutics in NAFLD. Using a network meta-analysis, we sought to examine the effectiveness of antidiabetic agents for the treatment of NAFLD in patients with type 2 diabetes mellitus.MethodsMedline and Embase were searched for randomized controlled trials relating to the use of antidiabetic agents, including sodium-glucose transport protein 2 (SGLT2) inhibitors, glucagon-like peptide-1 receptor agonists, and peroxisome proliferator-activated receptor gamma (PPARγ) agonists, biguanides, sulfonylureas and insulin, on NAFLD in patients with diabetes. The p-score was used as a surrogate marker of effectiveness.ResultsA total of 14 articles were included in the analysis. PPARγ agonists were ranked as the best treatment in steatosis reduction, resulting in the greatest reduction of steatosis. There was statistical significance between PPARγ agonists [mean difference (MD): ?6.02%, confidence interval (CI): ?10.37% to ?1.67%] and SGLT2 inhibitors (MD: ?2.60%, CI: ?4.87% to ?0.33%) compared with standard of care for steatosis reduction. Compared with PPARγ agonists, SGLT2 inhibitors resulted in a statistical significant reduction in fibrosis (MD: ?0.06, CI: ?0.10 to ?0.02). Body mass index reduction was highest in SGLT2 inhibitors and glucagon-like peptide-1 receptor agonists. Additionally, SGLT2 inhibitors were ranked as the best treatment for increasing high-density lipoprotein and reducing low-density lipoprotein.ConclusionGlucagon-like peptide-1 receptor agonists and SGLT2 inhibitors were suitable alternatives for the treatment of NAFLD in those with type 2 diabetes mellitus with a reduction in body mass index, fibrosis, and steatosis. SGLT2 inhibitors also have the added benefit of lipid modulation. 相似文献
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Laura Meek Ruth C. Martin Xueyan Shan P. Andrew Karplus David W. S. Mok Machteld C. Mok 《Journal of Plant Growth Regulation》2008,27(2):192-201
O-Glycosides of the cytokinin zeatin are found in many plant tissues. They provide protection against degradative enzymes
and may serve as cytokinin reserves. Two zeatin glycosyltransferase (GT) genes, an O-glucosyltransferase (ZOG1) from Phaseolus lunatus and an O-xylosyltransferase (ZOX1) from P. vulgaris, were previously isolated. Five novel bean and soybean GT genes with high sequence identity to ZOG1 were isolated, sequenced, and expressed, along with two such genes from rice and one from tomato. None of the recombinant
proteins showed GT activity with zeatin. By comparing the ZOG1 sequence to the 3D model of Medicago truncatula UGT71G1, four regions possibly important to zeatin binding were identified, and mutation studies identified one amino acid
within each region (R59, D87, L127, and F149) whose mutation strongly impaired enzyme activity. The new bean and soybean GTs
differ from ZOG1 in one (PlGT2 and GmGT2) to three (GmGT1) of these residues. Mutation of one such GT (PlGT2) to render it identical to ZOG1 at the four implicated residues conferred low enzyme activity, providing further support
for the importance of these amino acids in recognizing zeatin as substrate.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献