Reproductive isolation and the maintenance of species boundaries in two serpentine endemic Jewelflowers

Speciation occurs when reproductive barriers substantially reduce gene flow between lineages. Understanding how specific barriers contribute to reproductive isolation offers insight into the initial forces driving divergence and the evolutionary and ecological processes responsible for maintaining diversity. Here, we quantified multiple pre‐ and post‐pollination isolating barriers in a pair of closely related California Jewelflowers (Streptanthus, Brassicaceae) living in an area of sympatry. S. breweri and S. hesperidis are restricted to similar serpentine habitats; however, populations are spatially isolated at fine‐scales and rarely co‐occur in intermixed stands. Several intrinsic postzygotic barriers were among the strongest we quantified, yet, postzygotic barriers currently contribute little to overall reproductive isolation due to the cumulative strength of earlier‐acting extrinsic barriers, including spatial isolation, and flowering time and pollinator differences. Data from multiple years suggest that pre‐pollination barriers may have different strengths depending on annual environmental conditions. Similarly, crossing data suggest that the strength of intrinsic isolation may vary among different population pairs. Estimates of total reproductive isolation in S. breweri and S. hesperidis are robust to uncertainty and variability in individual barrier strength estimates, demonstrating how multiple barriers can act redundantly to prevent gene flow between close relatives living in sympatry.     

JMJD6在胃癌组织中的表达及意义

目的:检测JMJD6蛋白在胃癌组织及相应癌旁正常组织中的表达情况,并分析JMJD6蛋白表达与胃癌患者临床病理参数及预后的关系。方法:应用免疫组织化学方法检测JMJD6蛋白在胃癌组织及相应癌旁正常组织中的表达情况,进一步用Kaplan-Meier生存分析、COX比例风险回归模型等统计学方法研究JMJD6表达与胃癌患者临床病理参数及预后的关系。结果:JMJD6在胃癌组织中的表达阳性率显著高于癌旁正常组织(P=0.001);JMJD6在胃癌组织的高表达与肿瘤临床分期(P=0.008)、病理分级(P=0.001)、局部浸润深度(P=0.028)、有无淋巴结转移(P=0.001)等显著相关;Kaplan-Meier生存分析结果表明JMJD6高表达的胃癌患者术后总体生存率显著低于JMJD6低表达的患者(P=0.023)。结论:JMJD6在胃癌的发生发展中可能发挥了癌基因样作用,可能作为胃癌治疗的潜在靶点。     

入伍新训中膝关节损伤的特点与防治研究

目的：通过对某部新入伍官兵训练中膝关节损伤发生原因、特点进行流行性病学调查和分析,为合理训练,预防损伤发生和 治疗相关伤病提供指导依据。方法：对某部2013 年度450 名新入伍官兵的训练伤发病情况进行统计分析,重点分析膝关节损伤 发生率、伤病类型和致伤原因,并对其严重者进行关节镜治疗,观察和分析术后随访效果。结果：某部新兵的训练伤发生率为 20.0%。以关节急性扭伤最为多见,占81.1%。其中膝关节损伤共发生32 例,占训练伤发病率为7.1%,占训练伤发病率43.8%,其 中膝关节周围肌肉损伤20 例、交叉韧带损伤1 例、半月板损伤9 例、侧副韧带损伤2 例。致伤率最高的前3 位科目是5000 米负 重跑、跨越障碍训练、格斗训练,共27 例,占膝关节训练伤总数的84.4%。所有受伤患者中,12 例行手术治疗,20 例给予石膏、支具 固定、休息等保守治疗。经随访所有患者均得到较好的功能恢复。结论：对于新兵膝关节训练伤预防工作非常重要,避免致残;关 节镜手术技术的进步对于膝关节军事训练伤治疗有良好的效果。     

The effect of lichen‐dominated biological soil crusts on growth and physiological characteristics of three plant species in a temperate desert of northwest China

Biocrusts (biological soil crusts) cover open spaces between vascular plants in most arid and semi‐arid areas. Information on effects of biocrusts on seedling growth is controversial, and there is little information on their effects on plant growth and physiology. We examined impacts of biocrusts on growth and physiological characteristics of three habitat‐typical plants, Erodium oxyrhynchum, Alyssum linifolium and Hyalea pulchella, growing in the Gurbantunggut Desert, northwest China. The influence of biocrusts on plant biomass, leaf area, leaf relative water content, photosynthesis, maximum quantum efficiency of PSII (F_v/F_m), chlorophyll, osmotic solutes (soluble sugars, protein, proline) and antioxidant enzymes (superoxide dismutase, catalase, peroxidase) was investigated on sites with or without biocrust cover. Biomass, leaf area, leaf water content, photosynthesis, F_v/F_m and chlorophyll content in crusted soils were higher than in uncrusted soils during early growth and lower later in the growth period. Soluble sugars, proline and antioxidant enzyme activity were always higher in crusted than in uncrusted soils, while soluble protein content was always lower. These findings indicate that biocrusts have different effects on these three ephemeral species during growth in this desert, primarily via effects on soil moisture, and possibly on soil nutrients. The influence of biocrusts changes during plant development: in early plant growth, biocrusts had either positive or no effect on growth and physiological parameters. However, biocrusts tended to negatively influence plants during later growth. Our results provide insights to explain why previous studies have found different effects of biocrusts on vascular plant growth.     

The importance of reproductive interference in ecology and evolution: from organisms to communities

Knowledge of species interactions is vital to understand ecological and evolutionary patterns in nature. Traditional species interactions (e.g., competition, predation, symbiosis) have received a great deal of deserved attention and their general importance in shaping the evolution of populations and structure of communities is unquestioned. Recently, reproductive interference has been receiving attention as an important species interaction. Reproductive interference is defined as interspecific reproductive activities that decrease the fitness of at least one of the species involved in the interaction. Reproductive interference has the potential to affect the evolutionary trajectories of populations and structure of communities. Here, I comment on seven papers that make up this special feature on reproductive interference. Along the way I highlight key discoveries of these studies and areas of research that may contribute to our understanding of the causes and consequences of reproductive interference.     

Functional morphology of the male caudal appendages of the damselfly Ischnura elegans (Zygoptera: Coenagrionidae)

Odonata are usually regarded as one of the most ancient extant lineages of winged insects. Their copulatory apparatus and mating behavior are unique among insects. Male damselflies use their caudal appendages to clasp the female's prothorax during both copulation and egg-laying and have a secondary copulatory apparatus for sperm transfer. Knowledge of the functional morphology of the male caudal appendages is the basis for understanding the evolution of these structures in Odonata and respective organs in other insects. However, it is still not exactly known how the zygopteran claspers work. In this study, we applied micro-computed tomography and a variety of microscopy techniques to examine the morphology, surface microstructure, cuticle material composition and muscle topography of the male caudal appendages of Ischnura elegans. The results indicate that the closing of the paraproctal claspers is mainly passive. This indirect closing mechanism is very likely supported by high proportions of the elastic protein resilin present in the cuticle of the paraproctal bases. In addition, the prothoracic morphology of the female plays an important role in the indirect closing of the male claspers. Our data indicate that both structures – the male claspers and the female prothoracic hump – function together like a snap-fastener.     

Accumulation of Trace Metals by Mangrove Plants in Indian Sundarban Wetland: Prospects for Phytoremediation

The work investigates on the potential of ten mangrove species for absorption, accumulation and partitioning of trace metal(loid)s in individual plant tissues (leaves, bark and root/pneumatophore) at two study sites of Indian Sundarban Wetland. The metal(loid) concentration in host sediments and their geochemical characteristics were also considered. Mangrove sediments showed unique potential in many- fold increase for most metal(loid)s than plant tissues due to their inherent physicochemical properties. The ranges of concentration of trace metal(loid)s for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in plant tissue were 0.006–0.31, 0.02–2.97, 0.10–4.80, 0.13–6.49, 4.46–48.30, 9.2–938.1, 0.02–0.13, 9.8–1726, 11–5.41, 0.04–7.64, 3.81–52.20 μg g ^?1respectively. The bio- concentration factor (BCF) showed its maximum value (15.5) in Excoecaria agallocha for Cd, suggesting that it can be considered as a high-efficient plant for heavy metal bioaccumulation. Among all metals, Cd and Zn were highly bioaccumulated in E. agallocha (2.97 and 52.2 μg g ^?1 respectively. Our findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts, as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values.     

引起青稞和燕麦鞘腐病的无性型菌物新属种——禾生指葡孢霉

引起甘肃及邻省青稞和燕麦鞘腐病的病原菌为无性型真菌anamorphic fungi中一未描述的丛梗丝孢菌moniliaceous hyphomycete。该菌分生孢子梗无色,散生,直立或匍匐;交互、叉状、聚伞状或帚状分枝。产孢细胞簇生于分生孢子梗末级分枝顶端成指状或掌状,顶部常具齿状着孢点,全壁芽生式产孢。分生孢子无色、单胞,罕有一个隔膜,近球形、卵圆形、倒梨形、纺锤形、葫芦形或不规则形,表面具网状脊或疣突,在孢梗顶端常聚集成葡萄状。分生孢子群体白色,随培养物老化,渐变为淡黄色。本菌与葡萄孢属Botrytis及其他Botrytis-like形态相似属明显不同,故建立指葡孢霉属Dactylobotrys(新属);模式种为禾生指葡孢霉Dactylobotrys graminicola(新种)。模式标本保存在中国科学院菌物标本馆(HMAS 245110,主模式)和甘肃省农业科学院植物保护研究所植物病害标本室(GAPP 1131,等模式)。     

北京典型景观水体好氧反硝化菌组成特征

好氧反硝化菌对环境水体氮素的循环起到非常重要的作用。对北京市6个典型景观水体中好氧反硝化菌进行富集培养和分离,并开展菌株的16S rRNA基因测序和组成特征分析。结果表明,从6个水体中共富集分离得到80株好氧反硝化菌,均为变形菌门 (Proteobacteria),聚类于其3个纲(α-Proteobacteria、β-Proteobacteria、γ-Proteobacteria),分属于9个属,31个物种。其中90%左右的菌株具有良好的好氧反硝化能力,是水体进行生物脱氮修复的重要微生物基础。在不同景观水体中,好氧反硝化菌表现出较为明显的分布差异性和性能差异性,除了普遍存在的假单胞菌属（Pseudomonas）和不动杆菌属（Acinetobacter）外,每个水体基本都有属于自己的特异菌属,其中重要的特异菌属包括Alishewanella、Delftia、Hydrogenophaga和Rheinheimera,这对水体修复具有指导意义。