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Habitat-dependent diversification and parallel molecular evolution: Water scavenger beetles as a case study
Habitat shift is a key innovation that has contributed to the extreme diversification of insects. Most groups are well-adapted to more or less specific environments and shifts usually only happen between similar habitats. To colonize a pro- foundly different habitat type does not only present ecological opportunities but also great challenges. We used Hydrophiloidea (water scavenger beetles) as a system to study transitions between terrestrial and aquatic environments. We estimated the diversi- fication rate of different clades using phylogenetic trees based on a representative taxon sampling and six genes. We also investi- gated possible evolutionary changes in candidate genes following habitat shifts. Our results suggest that the diversification rate is relatively slow (0.039-0.050 sp/My) in the aquatic lineage, whereas it is distinctly increased in the secondarily terrestrial clade (0.055-0.075 sp/My). Our results also show that aquatic species have a G (Glycine) or S (Serine) amino acid at a given site of COI, while terrestrial species share an A (Alanine) amino acid with terrestrial outgroups. This indicates that habitat factors may create selection pressure on the evolution of functional genes and cause homoplasy in molecular evolution [Current Zoology 60 (5): 561-570, 2014 ]Ke-Qing SONG,Huai-Jun XUE,Rolf G BEUTEL,Ming BAI,Dong-Ju BIAN,Jie LIU,Yong-Ying RUAN,Wen-Zhu LI,Feng-Long JIA,Xing-Ke YANG - 动物学报(英文版)文章来源： 万方数据 -
载脂蛋白A-I模拟肽D-4F对巨噬细胞源性泡沫细胞清道夫受体A1的抑制作用
目的:研究载脂蛋白A-I模拟肽D-4F对氧化低密度脂蛋白(oxidized low-density lipoprotein,oxLDL)所诱导的巨噬细胞源性泡沫细胞清道夫受体A1(scavenger receptor A1,SR-A1)的抑制作用及其机制.方法:体外培养RAW264.7巨噬细胞,给予不同浓度的D-4F(12.5、25和50 mg/L)、紊乱模拟肽sD-4F(50 mmol/L)处理1h或者5 mmol/L内质网应激(endoplasmic reticulum stress,ERS)抑制剂4-苯丁酸处理30 min后,再加入ox-LDL(100 mg/L)继续培养12 h.另外培养巨噬细胞给予50 mg/L D-4F或sD-4F处理1 h,再加入2 mg/L ERS诱导剂衣霉素(tunicamycin,TM)处理4 h.MTT法检测细胞活力;试剂盒检测细胞内总胆固醇含量;分别采用免疫印迹法和实时荧光定量聚合酶链反应(real-time PCR)技术检测SR-A1和ERS标志分子葡萄糖调节蛋白78(glucose-regulated protein 78,GRP78)蛋白和mRNA表达变化;采用多功能酶标仪检测DiI-ox-LDL摄取情况.结果:D-4F明显减轻ox-LDL所诱导的巨噬细胞损伤和细胞内的胆固醇蓄积.ox-LDL可显著上调SR-A1和GRP78表达,而D-4F对上述变化具有明显抑制作用,且呈浓度依赖性.D-4F显著抑制TM所诱导的SR-A1和GRP78蛋白水平以及巨噬细胞对ox-LDL的摄取.结论:D-4F可通过抑制SR-A1表达减轻ox-LDL所诱导的巨噬细胞内胆固醇蓄积和细胞损伤,其机制可能与抑制GRP78介导的ERS信号途径有关.赵莉,姚树桐,陈军,苗成,李严严,田华,周健,翟雷,桑慧,王义围,秦树存 - 中国病理生理杂志文章来源： 万方数据
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