Positive selection at reproductive ADAM genes with potential intercellular binding activity

Many genes with a role in reproduction, including those implicated in fertilization and spermatogenesis, have been shown to evolve at a faster rate relative to genes associated with other functions and tissues. These survey studies usually group a wide variety of genes with different characteristics and evolutionary histories as reproductive genes based on their site of expression or function. We have examined the molecular evolution of the ADAM (a disintegrin and metalloprotease) gene family, a structurally and functionally diverse group of genes expressed in reproductive and somatic tissue to test whether a variety of protein characteristics such as phylogenetic clusters, tissue of expression, and proteolytic and adhesive function can group fast evolving ADAM genes. We found that all genes were evolving under purifying selection (d(N)/d(S) < 1), although reproductive ADAMs, including those implicated in fertilization and spermatogenesis, evolved at the fastest rate. Genes with a role in binding to cell receptors in endogenous tissue appear to be evolving under purifying selection, regardless of the tissue of expression. In contrast, positive selection of codon sites in the disintegrin/cysteine-rich adhesion domains was detected exclusively in ADAMs 2 and 32, two genes expressed in the testis with a potential role in sperm-egg adhesion. Positive selection was detected in the transmembrane/cytosolic tail region of ADAM genes expressed in a variety of tissues.     

胆囊切除术医源性胆管损伤的处理

目的:探讨开腹胆囊切除术医源性胆道损伤的诊断、手术时机和手术方式的选择。方法:对18例胆道损伤进行分析总结:分别施行了胆管修补、T管引流术10例,保守治疗2例,Roux-en-Y胆肠吻合术6例。结果:3例术后过早拔管发生吻合口狭窄,再次手术。1例因梗阻性胆管炎并发肝功能衰竭、多器官功能衰竭死亡。1例因胆肠吻合术后并发消化道出血、肝昏迷死亡。余术后良好。结论:尽早发现及正确处理对提高疗效和预防术后胆管狭窄起着决定性的作用。术中发现胆管损伤立即行端端吻合加T管引流;术后数天发现或多次胆道修补术失败者,则宜行规范的Roux-en-Y胆肠吻合术。     

Establishment and characterization of conditionally immortalized endothelial cell lines from the thoracic duct and inferior vena cava of tsA58/EGFP double-transgenic rats

The basic biology of blood vascular endothelial cells has been well documented. However, little is known about that of lymphatic endothelial cells, despite their importance under normal and pathological conditions. The lack of a lymphatic endothelial cell line has hampered progress in this field. The objective of this study has been to establish and characterize lymphatic and venous endothelial cell lines derived from newly developed tsA58/EGFP transgenic rats harboring the temperature-sensitive simian virus 40 (SV40) large T-antigen and enhanced green fluorescent protein (EGFP). Endothelial cells were isolated from the transgenic rats by intraluminal enzymatic digestion. The cloned cell lines were named TR-LE (temperature-sensitive rat lymphatic endothelial cells from thoracic duct) and TR-BE (temperature-sensitive rat blood-vessel endothelial cells from inferior vena cava), respectively, and cultured on fibronectin-coated dishes in HuMedia-EG2 supplemented with 20% fetal bovine serum and Endothelial Mitogen at a permissive temperature, 33°C. A temperature shift to 37°C resulted in a decrease in proliferation with degradation of the large T-antigen and cleavage of poly (ADP-ribose) polymerase. TR-LE cells expressed lymphatic endothelial markers VEGFR-3 (vascular endothelial growth factor receptor), LYVE-1 (a lymphatic endothelial receptor), Prox-1 (a homeobox gene product), and podoplanin (a glomerular podocyte membrane mucoprotein), together with endothelial markers CD31, Tie-2, and VEGFR-2, whereas TR-BE cells expressed CD31, Tie-2, and VEGFR-2, but no lymphatic endothelial markers. Thus, these conditionally immortalized and EGFP-expressing lymphatic and vascular endothelial cell lines might represent an important tool for the study of endothelial cell functions in vitro.M. Matsuo and K. Koizumi contributed equally to this work. This study was supported in part by Grants-in-Aid for the 21st Century COE Program and for CLUSTER (Cooperative Link of Unique Science and Technology for Economy Revitalization) from the Ministry of Education, Culture, Sports, Science, and Technology, Japan.     

Oviposition response of Simulium reptans (Diptera: Simuliidae) to the presence of conspecific eggs

Abstract.

• 1 The oviposition behaviour of Simulium reptans L. is described from two sites on the River Spey, Scotland. Female aggregations were observed immediately downstream of oviposition sites and were composed mainly of gravid flies (range 60–80%0) together with smaller numbers that were either freshly bloodfed (range 2–17%) or infected with mermithid nematodes (range 0–30%).
• 2 The time from landing on the oviposition sites to the onset of oviposition was recorded. The time in the presence of greater than 1-day-old eggs did not significantly differ from sites with no eggs present. However, the presence of freshly laid or I-day-old eggs significantly shortened the time to onset of oviposition. The cues that elicit oviposition are unknown but it is speculated that they may involve a pheromone.

     

ESTIMATING PHENOTYPIC SELECTION IN AGE‐STRUCTURED POPULATIONS BY REMOVING TRANSIENT FLUCTUATIONS

An extension of the selection differential in the Robertson–Price equation for the mean phenotype in an age‐structured population is provided. Temporal changes in the mean phenotype caused by transient fluctuations in the age‐distribution and variation in mean phenotype among age classes, which can mistakenly be interpreted as selection, will disappear if reproductive value weighting is applied. Changes in any weighted mean phenotype in an age‐structured population may be decomposed into between‐ and within‐age class components. Using reproductive value weighting the between‐age class component becomes pure noise, generated by previous genetic drift or fluctuating selection. This component, which we call transient quasi‐selection, can therefore be omitted when estimating age‐specific selection on fecundity or viability within age classes. The final response can be computed at the time of selection, but can not be observed until lifetime reproduction is realized unless the heritability is one. The generality of these results is illustrated further by our derivation of the selection differential for the continuous time age‐structured model with general age‐dependent weights. A simple simulation example as well as estimation of selection components in a house sparrow population illustrates the applicability of the theory to analyze selection on the mean phenotype in fluctuating age‐structured populations.     

宁夏枸杞的大、小孢子发生和雌、雄配子体发育

在幼小花药横切面上,每个角隅处可见一层拱形孢原细胞,其经过平周分裂形成初生造孢细胞、次生造孢细胞,发育为小孢子母细胞。减数分裂过程中胞质分裂为同时型。四分体为四面体型。成熟花粉粒含二细胞,具三孔沟型萌发孔。花药绒毡层由二部分组成:药壁区的绒毡层由初生壁细胞所产生,药隔区的由药隔细胞直接转化成,为双重起源,呈二型性,属分泌型。雌蕊由二个心皮构成二室子房,中轴胎座。倒生胚珠具单珠被、薄珠心,珠被绒毡层。胚囊发育为蓼型。在胚囊细胞分化后,组成胚囊的四种细胞继续发育,表现出各自的形态学变化。     

Access to mates in a territorial ungulate is determined by the size of a male's territory, but not by its habitat quality

1. Territoriality is commonly associated with resource defence polygyny, where males are expected to gain access to females by anticipating how resources will influence female distribution and competing for resource-rich sites to establish their zone of dominance. 2. We tested this hypothesis in European roe deer (Capreolus capreolus) by simultaneously assessing the influence of resources on female distribution and the influence of female distribution on male distribution and breeding success using paternity analyses. 3. Females did not fully distribute themselves among male territories in relation to resources. As a result, relative female abundance in a male's territory depended on territory size, but not on its habitat quality. In turn, relative female abundance in a male's territory determined, at least partially, his breeding success. 4. Interestingly, male territory size, and hence access to females, was partly determined by male body mass (all males) and by residual antler size (subadults only). The latter result suggests that large antlers may be important to young males for establishing their first territory, which is then usually retained for all subsequent reproductive seasons. 5. To conclude, although territoriality of male roe deer has certainly evolved as a tactic for ensuring access to mates, our results suggest that it does not really conform to a conventional resource defence polygyny strategy, as males seem to gain no obvious benefit from defending a territory in an area of high habitat quality in terms of enhanced access to mates. 6. This may explain the stability of male territories between years, suggesting that male territoriality conforms to an 'always stay' and 'low risk-low gain' mating strategy in roe deer.     

Studies on reproductive strategies of Vitex negundo L. var. heterophylla (Franch.) Rehder (Lamiaceae) based on morphological characteristics and SSR markers

Vitex negundo L. var. heterophylla (Franch.) Rehder (Lamiaceae) is an important tree species for soil and water conservation, yet the reproductive ecology of this species remains to be elucidated. To investigate the reproductive traits of V. negundo var. heterophylla, the phenology, morphological characteristics (a suite of characters was assessed: floral morphology, nectar production, pollen viability, and stigma receptivity) and mating system of this species were systematically revealed for the first time in this study. Phenological observations, morphological measurements, and nectar production analysis were conducted during anthesis. Pollen viability and stigma receptivity at different flowering stages were measured by biochemical methods. Finally, genetic analysis based on SSR markers was used to reveal the mating system; outcrossing index and pollen‐ovule ratio were also calculated to help analysis. V. negundo var. heterophylla showed several obvious characteristics of outcrossing, such as abundant and attractive flowers, secreting nectar, and emitting scent. In addition, mechanisms such as homogamy and a short anther‐stigma distance that can promote self‐fertilization were also identified in this species. The coexistence of selfing and outcrossing characteristics demonstrates a predominantly outcrossed mixed mating system (outcrossing rate, t = 95%). The scientific information provided by this study may contribute to conservation of V. negundo var. heterophylla from a reproductive perspective.