Assessment of variability among morphological and molecular characters in wild populations of mint [Mentha longifolia (L.) L.] germplasm

Mentha longifolia is an important medicinal and aromatic perennial herb that exhibits wide distribution range from sub-tropical to temperate regions. In the present study, agro-morphological traits and genetic differences in 19 different populations of M. longifolia were studied to evaluate the level and extent of its diversity. Analysis of variance (ANOVA) showed that the different phenotypic characters show considerable differences among various populations and was significant at p < 0.05. Molecular diversity analysis performed by using arbitrary amplified eleven ISSR primers generated a total of 121 amplicons that range within the size of 200–2500 base pairs (bp). Each primer on average generated 11 amplicons with percentage polymorphism being 100. The analysis of molecular variance (AMOVA) showed more (64%) among population genetic diversity and less (36%) within the populations. Greater genetic differentiation (Gst = 0.6852) among these populations occurs due to low gene flow (Nm = 0.2297) and greater habitat variability. Geographic and genetic distances were positively correlated according to Mantel’s test. In order to remove any kind of biases, we used R software to perform cluster and redundancy analysis to analyse the extent of relatedness among studied populations. In terms of morphological and molecular aspects, the populations were grouped into four and five clusters respectively based on hierarchical clustering method. The results demonstrated that M. longifolia displays a great degree of morphological and genetic variation and can be utilized in breeding, genetic improvement, and gene bank conservation programmes in future.     

栗背短脚鹎的种群分化与遗传多样性

栗背短脚鹎(Hemixos castanonotus)是我国南方山区常见的杂食性鸟类。为探明其遗传多样性及分化现状,采用线粒体Cyt b基因和7个核基因非编码区片段作为分子标记,对分布于广东、广西、海南、贵州和江西五省(自治区)的栗背短脚鹎11个地理种群进行了遗传分化及遗传多样性研究。基于所获得的Cyt b基因866 bp和7个核基因内含子序列6 808 bp进行分析。结果显示,在Cyt b基因中,共检测到37个单倍型,共享单倍型占单倍型总数的35.6%,推测这些共享单倍型可能属于祖先单倍型。分子方差分析结果显示,遗传变异主要来源于种群内部(79.77%)。Tajima’s D和Fu’s Fs中性检验分析结果均支持栗背短脚鹎种群可能曾经历过种群扩张现象。基于7个核基因内含子联合序列的贝叶斯天际线(BSP)分析,推断其种群在大约5.3 ~ 3.7百万年前(Mya)和约0.7 ~ 0.3百万年前(Mya)发生过扩张。基于Cyt b基因的贝叶斯系统发育分析,11个地理种群共分为两支,一支为海南猴猕岭地理种群,属指名亚种(H. c. castanonotus),其他10个地理种群聚为另一支,属H. c. canipennis亚种,并且后者尚未形成显著的地理结构,单倍型网络图分析也获得相似的结果。本研究所用分子数据基本支持两个亚种的分化,对于存在争议的广西南部分布的指名亚种,其分子数据与形态学亚种归属不一致,有待更深入研究。     

海南脆蛇蜥的分类地位研究

海南脆蛇蜥（Dopasia hainanensis Yang, 1983）为杨戎生根据1号来自海南吊罗山的标本命名,其形态和分子系统发育关系少有人研究。2018年至2019年间,作者获赠2号来自海南脆蛇蜥模式产地的标本和1号来自脆蛇蜥（D. harti）模式产地的组织样。经过形态特征比较和线粒体Cyt b基因序列分析,发现两地样本Cytb基因序列的遗传距离很近（仅有4.96%）,且形态差异不明显,难以找到典型鉴别特征。本文研究成果支持海南脆蛇蜥和台湾脆蛇蜥（Ophisaurus formosensis）为脆蛇蜥的同物异名,同时认为越南的“海南脆蛇蜥”可能为一未描述的新种或新亚种。鉴于脆蛇蜥种下遗传差异较大,其种下关系亟待进一步研究。     

Development of microsatellite markers for the neotropical tree species Dipteryx alata (Fabaceae)

? Premise of the study: Microsatellite markers were developed for the population genetic analyses of the neotropical tree Dipteryx alata (Fabaceae). ? Methods and Results: Microsatellites were developed from a genomic shotgun library. Polymorphism at each microsatellite loci was analyzed based on 94 individuals from three populations. Eight loci amplified successfully and presented one to 10 alleles, and expected heterozygosities ranged from 0.097 to 0.862. Four loci also amplified in Pterodon emarginatus and presented similar polymorphism. ? Conclusion: The eight microsatellite primer pairs are potentially suitable for population genetic studies and successfully amplified in another Fabaceae species.     

John Kendrew and myoglobin: Protein structure determination in the 1950s

The essay reviews John Kendrew's pioneering work on the structure of myoglobin for which he shared the Nobel Prize for Chemistry in 1962. It reconstructs the status of protein X‐ray crystallography at the time Kendrew entered the field in 1945, after distinctive service in operational research during the war. It reflects on the choice of sperm whale myoglobin as research material. In particular, it highlights Kendrew's early use of digital electronic computers for crystallographic computations and the marshaling of other tools and approaches that made it possible to solve the structure at increasing resolution. The essay further discusses the role of models in structure resolution and their broader reception. It ends by briefly reviewing Kendrew's other contributions in the formation and institutionalization of molecular biology.     

Phosphatidylinositol‐4 kinase III beta and oxysterol‐binding protein accumulate unesterified cholesterol on poliovirus‐induced membrane structure

Studies on anti‐picornavirus compounds have revealed an essential role of a novel cellular pathway via host phosphatidylinositol‐4 kinase III beta (PI4KB) and oxysterol‐binding protein (OSBP) family I in poliovirus (PV) replication. However, the molecular role for this pathway in PV replication has yet to be determined. Here, viral and host proteins modulating production of phosphatidylinositol 4‐phosphate (PI4P) and accumulation of unesterified cholesterol (UC) in cells were analyzed and the role of the PI4KB/OSBP pathway in PV replication characterized. Virus protein 2BC was identified as a novel interactant of PI4KB. PI4KB and VCP/p97 bind to a partially overlapped region of 2BC with different sensitivity to a 2C inhibitor. Production of PI4P and accumulation of UC were enhanced by virus protein 2BC, but suppressed by virus proteins 3A and 3AB. In PV‐infected cells, a PI4KB inhibitor suppressed production of PI4P, and both a PI4KB inhibitor and an OSBP ligand suppressed accumulation of UC on virus‐induced membrane structure. Inhibition of PI4KB activity caused dissociation of OSBP from virus‐induced membrane structure in PV‐infected cells. Synthesis of viral nascent RNA in PV‐infected cells was not affected in the presence of PI4KB inhibitor and OSBP ligand; however, transient pre‐treatment of PV‐infected cells with these inhibitors suppressed viral RNA synthesis. These results suggest that virus proteins modulate PI4KB activity and provide PI4P for recruitment of OSBP to accumulate UC on virus‐induced membrane structure for formation of a virus replication complex.     

Sequence and structure space of RNA-binding peptides

Studies of RNA-binding peptides, and recent combinatorial library experiments in particular, have demonstrated that diverse peptide sequences and structures can be used to recognize specific RNA sites. The identification of large numbers of sequences capable of binding to a particular site has provided extensive phylogenetic information used to deduce basic principles of recognition. The high frequency at which RNA-binding peptides are found in large sequence libraries suggests plausible routes to evolve sequence-specific binders, facilitating the design of new binding molecules and perhaps reflecting characteristics of natural evolution.     

Modulation of immunogenicity of poly(sarcosine) displayed on various nanoparticle surfaces due to different physical properties

Poly(sarcosine) displayed on polymeric micelle is reported to trigger a T cell‐independent type2 reaction with B1a cells in the mice to produce IgM and IgG3 antibodies. In addition to polymeric micelle, three kinds of vesicles displaying poly(sarcosine) on surface were prepared here to evaluate the amounts and avidities of IgM and IgG3, which were produced in mice, to correlate them with physical properties of the molecular assemblies. The largest amount of IgM was produced after twice administrations of a polymeric micelle of 35 nm diameter ( G1 ). On the other hand, the production amount of IgG3 became the largest after twice administrations of G3 (vesicle of 229 nm diameter) or G4 (vesicle of 85 nm diameter). The augmented avidity of IgG3 after the twice administrations compared with that at the single administration was the highest with G3 . These differences in immune responses are discussed in terms of surface density of poly(sarcosine) chains, nanoparticle size, hydrophobic component of poly(L‐lactic acid) or (Leu‐ or Val‐Aib)_n, and membrane elasticity of the nanoparticles. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.