Social group composition modulates the role of last male sperm precedence in post-copulatory sexual selection

In many species, the order in which males mate with a female explains much of the variation in paternity arising from post-copulatory sexual selection. Research in Drosophila suggests that mating order may account for the majority of the variance in male reproductive success. However, the effects of mating order on paternity bias might not be static but could potentially vary with social or environmental factors. To test this idea, we used an existing dataset, collated from an experiment we previously published (Morimoto et al., PLoS One, 11, 2016, e0154468), with the addition of unpublished data from the same experiment. These previous experiments manipulated larval density in Drosophila melanogaster which generated variation in male and female body size, assembled groups of individuals of different sizes, and measured the mating success and paternity share of focal males. The data presented here provides information on each focal male's mating order and the frequency in which focal males remated with same females (‘repetitive matings’). We combined this information with our previously reported focal male reproductive success to partition variance in paternity into male mating order and repetitive matings across groups that differed in the body size composition of males and females. We found, as expected, that male mating order explained a considerable portion of the variance in male paternity. However, we also found that the impact of male mating order on male paternity was influenced by the body size composition of groups. Specifically, males that tended to mate last had a greater paternity advantage, and displayed lower variance, in groups containing a heterogenous mixture male body sizes than in groups with a single male body size. Repetitive mating only had a minor contribution to the variance in male paternity share across all experiments. Overall, our findings contribute to the growing body of research showing that post-copulatory sexual selection is subject to socio-ecological influences.     

绿色木霉组蛋白去乙酰化酶编码基因TvRpd3在木霉生物防治作用中的功能分析

【目的】本文借助基因编辑技术在具有生物防治潜力的绿色木霉(Trichoderma viride)中敲除组蛋白去乙酰化酶编码基因TvRpd3,来研究TvRpd3基因及其编码蛋白在提高木霉病原菌拮抗能力中的作用。【方法】利用融合PCR和同源重组策略构建了TvRpd3基因缺失的突变菌株,通过对峙培养、表型观察、免疫组化检测、代谢组学分析等系统比较TvRpd3基因敲除前后菌株的组蛋白乙酰化修饰水平、次级代谢产物合成、病原菌拮抗能力以及田间防治效果等。【结果】与野生型菌株相比,缺失TvRpd3基因的木霉工程菌(?TvRpd3)对多种病原菌表现出了更强的对峙抑制效果,其所产的发酵液对小麦白粉病、烟草黑胫病和番茄枯萎病的防治效果分别提高了62.27%、57.45%和70.71%。同时,敲除TvRpd3基因也显著改变了木霉工程菌所产次级代谢产物的种类和产量,抗生性物质的产量大幅提高。【结论】绿色木霉TvRpd3基因及其介导的组蛋白乙酰化修饰在提高绿色木霉生物防治中起着重要作用。     

Refolding and proton pumping activity of a polyethylene glycol-bacteriorhodopsin water-soluble conjugate.

Bacteriorhodopsin (BR), from the purple membrane (PM) of Halobacterium halobium, was chemically modified with methoxypolyethylene glycol (m-PEG; molecular weight = 5,000 Da) succinimidyl carbonate. The polyethylene glycol-bacteriorhodopsin (m-PEG-SC-BR33) conjugate, containing one polyethylene glycol chain, was water soluble. The secondary structure of the conjugate in water appeared partially denatured, but was shown to contain alpha-helical segments by circular dichroism spectroscopy. The isolated bacteriorhodopsin conjugate, with added retinal, was refolded in a mixed detergent-lipid micelle and had an absorption maximum at 555 nm. The refolded conjugate was transferred into vesicles that pumped protons, upon illumination, as efficiently as did native BR. Modification of the PM with m-PEG did not alter the native structure or inhibit proton pumping, and therefore it is suggested that the glycol polymer is present as a moiety covalently linked to residues unnecessary for proton pumping and proper folding. The site of attachment of m-PEG was determined to be at either Lys 129 or Lys 159, with position Lys 129 the most probable site of attachment. The m-PEG-SC-BR33 could be stepwise refolded to the native conformation by the addition of trifluoroethanol to lower the dielectric constant, simulating the insertion of the BR into the phospholipid bilayer.     

Specificity and regulation of the mutator transposable element system in maize

The Mutator transposable element system is exceptional in many of its basic attributes. The high frequency and low specificity of mutant induction are both unusual and useful characteristics of the Mutator system. Other basic features are at least equally fascinating: the existence of multiple Mu element subfamilies with apparently unrelated internal sequences; the lack of correlation between Mu element transposition and excision; the complex inheritance of Mutator activity; the tight developmental regulation of Afufaror‐conditioned events; and the coordinated processes of element modification/inactivation, to name a few.

Molecular and genetic studies over the last 10 years have begun to explain many of these interesting properties and have uncovered new mysteries of Mutator biology. Both positive and negative regulators of the system have been identified and characterized to varying degrees. Insertion specificity has been observed at several levels. Recent accomplishments include the isolation of an autonomous Mu element and the discovery of maize lines with altered developmental regulation of Mutator‐derived mutability. This review defines the Mutator system, describes the status of current experimentation in the Mutator field, proposes models that may explain some aspects of Mutator behavior, and details future studies that will help elucidate the nature of the Mutator phenomenon.     

Floral sex ratio variation in hermaphrodites of gynodioeciousChionographis japonica var.kurohimensis Ajima et Satomi (Liliaceae)

Intrapopulation and interpopulation variations in floral sex ratio in hermaphrodites of gynodioeciousChionographis japonica var.kurohimensis (Liliaceae) were examined. The relative ratio of male flowers to total flowers (male and perfect flowers) decreased with plant size, suggesting size-dependent gender modification. The relative ratio of male flowers per population-basis is negatively correlated with the mean number of perfect flowers. Since the number of perfect flowers proportionally increased with plant size, populations showing low maleness consist of relatively bigger plants and are considered to be in high-quality environment. On the other hand, the relative ratio of male flowers per population basis is independent of female frequency in the population. Plasticity in gender expression probably plays an important role of maintenance of gynodioecy inC. japonica var.kurohimensis.     

RhoB的翻译后修饰与细胞命运

RhoB作为Rho家族的一员,其生物学活性和蛋白质水平的调控与其他成员有着较大的不同,在肿瘤的发生发展中也起着独特的作用。RhoB作为抑癌蛋白在肿瘤的靶向治疗上受到越来越多的关注,然而在有些类型的肿瘤中RhoB却起着促进肿瘤生长的作用,其中的分子机理还不清楚,亟待研究阐明。可逆的翻译后修饰是快速与精细调控RhoB功能的重要分子机制,对于维持正常细胞的生长、抑制细胞的早期癌变及肿瘤的发生发展至关重要。本文就RhoB翻译后修饰的研究,特别是其泛素化和SUMO化修饰之间的转化在肿瘤细胞命运决定中的作用进行综述,以期为探索RhoB的调控与肿瘤发生发展的机制,以及以RhoB为靶点的癌症治疗提供线索和思路。     

LDL的氧化修饰和氧化修饰LDL的组成和结构变化

与低密度脂蛋白(LDL)相比,氧化修饰LDL(O-LDL)的组成、结构和生物学特性发生了深刻的变化,而组成和结构的改变是生物学特性改变的基础.本文根据最近文献资料.结合我们实验室的工作.对LDL的氧化修饰、O-LDL的组成、结构改变,以及它们的机理作一简要综述.     

Study on the Adsorption of Cr3+ by Peanut Shell: Adsorption Kinetics,Thermodynamics, and Isotherm Properties

The pollution of heavy metals in soil to the environment is becoming more and more serious, resulting in the reduction of crop production and the occurrence of medical accidents. In order to remove heavy metal ions from soil and reduce the harm of heavy metals to the environment, modified peanut shell was used to adsorb Cr³⁺ in this article. The effects of different adsorption conditions on the adsorption rate and adsorption capacity of Cr³⁺ on ZnCl₂ modified peanut shell were studied, the best adsorption conditions were explored, and the relationship of kinetics, thermodynamics and adsorption isotherm properties of adsorption process were explored. The results showed that the optimum adsorption pH value, dosage, initial concentration, adsorption temperature and contact time of ZnCl₂ modified peanut shell were 2.5, 2.5 g/L, 75 μg/mL, 25 °C and 40 min, respectively. The prepared materials were characterized and analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD) analyzer. It was concluded that the modified peanut shell had a good adsorption capacity to Cr³⁺. The kinetic study showed that the adsorption process of Cr³⁺ on peanut shell modified by zinc chloride was in accordance with the quasi-second-order kinetic model. The adsorption process belonged to exothermic reaction and belonged to spontaneous reaction process. In summary, it is proved that zinc chloride modified peanut shell can efficiently adsorb Cr³⁺, which can be used for the treatment of heavy metal wastes in industry, which is beneficial to environmental protection and avoid heavy metal pollution.     

The polyamine-derived amino acid hypusine: its post-translational formation in eIF-5A and its role in cell proliferation

Summary The unusual amino acid hypusine [N -(4-amino-2-hydroxybutyl)lysine] is a unique component of one cellular protein, eukaryotic translation initiation factor 5A (eIF-5A, old terminology, eIF-4D). It is formed posttranslationally and exclusively in this protein in two consecutive enzymatic reactions, (i) modification of a single lysine residue of the eIF-5A precursor protein by the transfer of the 4-aminobutyl moiety of the polyamine spermidine to its-amino group to form the intermediate, deoxyhypusine [N -(4-aminobutyl)lysine] and (ii) subsequent hydroxylation of this intermediate to form hypusine. The amino acid sequences surrounding the hypusine residue are strictly conserved in all eukaryotic species examined, suggesting the fundamental importance of this amino acid throughout evolution. Hypusine is required for the activity of eIF-5Ain vitro. There is strong evidence that hypusine and eIF-5A are vital for eukaryotic cell proliferation. Inactivation of both of the eIF-5A genes is lethal in yeast and the hypusine modification appears to be a requirement for yeast survival (Schnier et al., 1991 [Mol Cell Biol 11: 3105–3114]; Wöhl et al., 1993 [Mol Gen Genet 241: 305–311]). Furthermore, inhibitors of either of the hypusine biosynthetic enzymes, deoxyhypusine synthase or deoxyhypusine hydroxylase, exert strong anti-proliferative effects in mammalian cells, including many human cancer cell lines. These inhibitors hold potential as a new class of anticancer agents, targeting one specific eukaryotic cellular reaction, hypusine biosynthesis.     

静电作用与修饰铜锌超氧化物歧化酶的稳定性

铜锌超氧化物歧化酶(Cu, Zn-SOD)表面的赖氨酸经化学修饰后, 酶的稳定性显著提高. 赖氨酸被修饰后, 酶的电荷结构遂发生变化, 从而影响到酶分子电场. 使用FDPB方法(有限差分法求解Poission-Boltzman方程)计算了酶修饰前后的静电场变化, 以及对维持酶的结构稳定起重要作用的Cu, Zn配位结构的影响.结果表明, Cu, Zn配位体的两级离解常数在酶修饰后分别约下降10³, 10⁶.