变形菌视紫红质十年的回顾与展望

变形菌视紫红质(proteorhodopsin,PR)是一类吸光色素膜蛋白,它是由7个跨膜ɑ-螺旋(A～G)组成的视蛋白(opsins)与色素视黄醛(retinal)通过共价键结合而形成。PR广泛存在于海洋和淡水水域的微生物中,是一种质子泵型的视紫红质,可在光的驱动下将质子从细胞质泵到胞质间隙,从而在细胞内外产生质子梯度,形成的化学势能被用于合成ATP、物质的跨膜运输以及驱动鞭毛运动等方面。据估算含PR的细菌在海洋水域中约占总细菌的13%,而每个含PR的细胞中的PR分子数约为2.5×104个。对PR功能的研究表明PR具有增强其宿主菌抵抗外界不良环境的能力;而对于PR三维结构的研究对PR的作用机理及其功能的研究将有更进一步的推动作用。     

啶虫脒对淡色库蚊幼虫的致死和亚致死影响

啶虫脒是日本曹达公司新开发的一种氯代烟碱类杀虫剂,为了探讨其用于蚊虫幼虫控制的可能性,我们在室内用浸渍法测定了啶虫脒对淡色库蚊幼虫的致死和亚致死影响,结果表明,淡色库蚊幼虫对啶虫脒较敏感,幼虫的死亡高峰出现在处理后第3天,幼虫的四个龄期中,一龄最敏感,四龄耐药力最强,二在处理后72h时的LC50值分别为0.020mg/L/升和0.296mg/L。幼虫在亚致死浓度的啶虫脒溶液作用下,发育期延长,蛹重下降。说明啶虫脒可用于蚊虫幼虫的控制。     

促性腺激素在白蚁脑中的免疫细胞化学定位

为研究昆虫卵泡刺激素 (FSH)和黄体生成素 (LH)的存在与分布 ,我们用免疫细胞化学染色技术对FSH和LH在尖唇散白蚁 (Reticulitermesaculabialis)脑中的分布进行了定位研究。结果显示 :FSH免疫阳性神经细胞及神经纤维分布在雌性繁殖蚁分飞期前脑的左叶、右叶及中部 ,雌性末龄若虫前脑的右叶 ,雄性繁殖蚁前脑的右叶 ;LH免疫阳性物质分布在雌、雄繁殖蚁前脑左叶 ;在工蚁和兵蚁中未见有FSH和LH免疫阳性物质存在。研究结果表明 :FSH和LH在白蚁脑中的存在具有发育阶段特异性 ,并且有可能像其在脊椎动物中那样参与调节性腺发育及精卵成熟 ;可能调节繁殖蚁、兵蚁、工蚁的产生     

Synthesizing double haploid hexaploid wheat populations based on a spontaneous alloploidization process

Doubled haploid(DH) populations are useful to scientists and breeders in both crop improvement and basic research.Current methods of producing DHs usually need in vitro culture for extracting haploids and chemical treatment for chromosome doubling.This report describes a simple method for synthesizing DHs(SynDH) especially for allopolyploid species by utilizing meiotic restitution genes.The method involves three steps:hybridization to induce recombination,interspecific hybridization to extract haploids,a...     

Comparison of the distribution of the repetitive DNA sequences in three variants of Cucumis sativus reveals their phylogenetic relationships

Repetitive DNA sequences with variability in copy number or/and sequence polymorphism can be employed as useful molecular markers to study phylogenetics and identify species/chromosomes when combined with fluorescence in situ hybridization(FISH).Cucumis sativus has three variants,Cucumis sativus L.var.sativus,Cucumis sativus L.var.hardwickii and Cucumis sativus L.var.xishuangbannesis.The phylogenetics among these three variants has not been well explored using cytological landmarks.Here,we concentrate on...     

No Intestinal Stem Cell Regeneration after Complete Progenitor Ablation in Drosophila Adult Midgut

<正>Adult stem cells or progenitors are essential for maintaining the normal structure and function of adult tissues(i.e.,homeostasis).One of the best examples is the adult intestinal epithelium which is constantly renewed by the progeny of intestinal stem cells(ISCs).The proliferation and differentiation of adult stem cells must be tightly controlled in order to maintain resident tissue homeostasis.Mis-regulation of stem     

The Special Column of Primate Behavior

It is a long-term policy to publish SPECIAL COLUMNsin Current Zoology, and I am delighted that thejournal is publishing this special column devoted to thetopic of Primate Behavior. The eight papers in this sectionpresent significant new data and synthesize thesefindings with existing information on sexual selection of