Enhanced gene replacements in Ku80 disruption mutants of the dermatophyte, Trichophyton mentagrophytes

The frequency of targeted gene disruption via homologous recombination is low in the clinically important dermatophyte, Trichophyton mentagrophytes . The Ku genes, Ku70 and Ku80 , encode key components of the nonhomologous end-joining pathway involved in DNA double-strand break repair. Their deletion increases the homologous recombination frequency, facilitating targeted gene disruption. To improve the homologous recombination frequency in T. mentagrophytes , the Ku80 ortholog was inactivated. The nucleotide sequence of the Ku80 locus containing a 2788-bp ORF encoding a predicted product of 728 amino acids was identified, and designated as TmKu80 . The predicted TmKu80 product showed a high degree of amino acid sequence similarity to known fungal Ku80 proteins. Ku80 disruption mutant strains of T. mentagrophytes were constructed by Agrobacterium tumefaciens -mediated genetic transformation. The average homologous recombination frequency was 73.3 ± 25.2% for the areA/nit-2 -like nitrogen regulatory gene ( tnr ) in Ku80⁻ mutants, about 33-fold higher than that in wild-type controls. A high frequency ( c . 67%) was also obtained for the Tri m4 gene encoding a putative serine protease. Ku80 ⁻ mutant strains will be useful for large-scale reverse genetics studies of dermatophytes, including T. mentagrophytes , providing valuable information on the basic mechanisms of host invasion.     

白念珠菌新型耐药基因MXR1的敲除与鉴定

目的 构建用于白念珠菌MXR1基因敲除的载体质粒,并通过Ura-Blaster策略敲除MXR1两条等位基因.方法 分别扩增白念珠菌MXR1基因ORF两侧上下游的片段,通过酶切与连接反应,将上下游片段分别插入到p5921质粒的hisG-URA 3-hisG盒两端,从而形成MXR1敲除载体质粒pUC-MXR1-URA3.通过Ura-Blaster策略将载体质粒转染到白念珠菌RM 1000内,并采用PCR和Southern-blot杂交方法鉴定各步转染、复筛所得的阳性克隆.结果 成功获得MXR1基因缺失的菌株.结论 MXR1基因缺失菌株的构建,有助于深入研究白念珠菌耐药机制.     

草地螟雄蛾生殖系统的形态和结构

针对目前关于草地螟Loxostege sticticalis L.雄成虫生殖系统结构和功能的研究相对缺乏的状况,本文利用光镜和扫描电镜系统研究了草地螟雄蛾的内外生殖器官及相关结构。草地螟雄蛾内外生殖器官集中于腹部第5¹0腹节;内生殖器官位于510腹节;内生殖器官位于5⁸腹节内腔中,由睾丸(testes)、贮精囊(seminal vesicle)、输精管(vas deferens)、附腺(accessory gland)和射精管(ejaculatory ducts)组成;外生殖器官为腹部第9、10腹节的特化结构,包括抱握器(harpes)、背兜(tegumen)、基腹弧(vinculum)、钩形突(uncus)、颚形突(gnathos)、阳茎囊(aedeagal caecum)和阳茎(phallus)。外生殖器中抱握器的端刺(furcella)方向为雄蛾区别于其它种类的一个重要形态学特征。该研究首次明确了草地螟雄蛾的生殖系统结构,并为锥额野螟蛾属中种间分类提供更多的科学依据。     

Impaired skin wound healing in peroxisome proliferator-activated receptor (PPAR)alpha and PPARbeta mutant mice

We show here that the alpha, beta, and gamma isotypes of peroxisome proliferator-activated receptor (PPAR) are expressed in the mouse epidermis during fetal development and that they disappear progressively from the interfollicular epithelium after birth. Interestingly, PPARalpha and beta expression is reactivated in the adult epidermis after various stimuli, resulting in keratinocyte proliferation and differentiation such as tetradecanoylphorbol acetate topical application, hair plucking, or skin wound healing. Using PPARalpha, beta, and gamma mutant mice, we demonstrate that PPARalpha and beta are important for the rapid epithelialization of a skin wound and that each of them plays a specific role in this process. PPARalpha is mainly involved in the early inflammation phase of the healing, whereas PPARbeta is implicated in the control of keratinocyte proliferation. In addition and very interestingly, PPARbeta mutant primary keratinocytes show impaired adhesion and migration properties. Thus, the findings presented here reveal unpredicted roles for PPARalpha and beta in adult mouse epidermal repair.     

Genetic Analysis of Plasmid-specific Pheromone Signaling Encoded by pPD1 in Enterococcus faecalis

Certain plasmids in Enterococcus faecalis encode a mating response to recipient-produced peptide sex pheromones. Targeted disruption of tra genes on pPD1 suggested that TraA plays a central role in the plasmid-specific pheromone signaling pathway. TraA functioned as a negative regulator for the pheromone-inducible conjugal transfer. Complementation analysis of pPD1 tra gene mutants by pAD1 suggested that the pheromone binding function of TraC was non-specific between these plasmids, but the function of TraA and the pheromone shutdown function of TraB are plasmid-specific.     

杀粉蝶菌素A1生物合成基因簇中甲基转移酶PieB2的功能

【目的】研究杀粉蝶菌素A1产生菌中甲基转移酶基因pieB2的功能。【方法】利用接合转移和同源重组双交换的方法,构建pieB2基因缺失突变株,以及利用接合转移的方法,构建回补菌株。通过高保真PCR克隆pieB2基因到表达载体pET28a上,构建质粒pJTU5997,转化入大肠杆菌E.coliBL21(DE3)/pLysE中诱导表达。利用高效液相色谱检测PieB2的体外酶活。【结果】获得了pieB2基因缺失的双交换突变株。发酵结果显示,该突变株不再产生杀粉蝶菌素A1,而是积累了一种脱甲基产物。N-末端融合组氨酸标签的PieB2在大肠杆菌中获得可溶性表达,通过体外催化证明了PieB2甲基转移酶的功能。【结论】体内遗传实验和体外生化实验证明了PieB2作为甲基转移酶在杀粉蝶菌素A1合成中的作用。     

EMF基因与植物营养生长

在高等植物中,外源和内源因素共同调控着植物从营养生长到生殖生长的转换。拟南芥EMF1和EMF2基因缺失的突变体不经过任何营养生长,种子萌发后便开花,这说明EMF基因是植物花发育的抑制基因。目前已从水稻、玉米、拟南芥等植物中克隆得到EMF同源基因,但其功能研究大多停留在拟南芥上。研究表明,EMF基因决定着植物营养生长阶段的发育,抑制植物开花。因此,开展EMF基因的分离、克隆和功能研究,有利于阐述植物营养生长过程阶段的抑花机制。对EMF基因的研究进展进行了综述,并提出EMF基因表达调控的闸门模型,以对EMF基因功能的进一步分析提供参考。     

不同温度条件下白纹伊蚊生命生殖力表

观察了20—30℃五个不同温度的白纹伊蚊Aedes altoptctusSkuse实验种群生命生殖力表,所得有关种群动态参数的值包括净增殖率R_o、增殖能力r_c、内禀增长能力r_m、周限增长速率λ,瞬时出生率b和瞬时死亡率d均与温度呈正相关,而平均世代周期长T呈负相关.而且各参数对温度的变化是敏感的.在m_x值曲线图中,加用了同龄种群产卵数的百分构成比曲线,该曲线反映了种群中各年龄组雌蚊生殖能力的分布.本文应用v=λ^(X₂-X₁),以X₂-X₁=e_x 计算同龄雌蚊不同温度条件下平均预期寿命天数,一个雌蚊所产生的雌性个体,以25℃条件下的V值明显地高于其他四个实验温度.     

The evolved psychological mechanisms of fertility motivation: hunting for causation in a sea of correlation

Cultural, ecological, familial and physiological factors consistently influence fertility behaviours, however, the proximate psychological mechanisms underlying fertility decisions in humans are poorly understood. Understanding the psychological mechanisms underlying human fertility may illuminate the final processes by which some of these known predictors have their influence. To date, research into the psychological mechanisms underlying fertility has been fragmented. Aspects of reproductive psychology have been examined by researchers in a range of fields, but the findings have not been systematically integrated in one review. We provide such a review, examining current theories and research on psychological mechanisms of fertility. We examine the methods and populations used in the research, as well as the disciplines and theoretical perspectives from which the work has come. Much of the work that has been done to date is methodologically limited to examining correlations between ecological, social and economic factors and fertility. We propose, and support with examples, the use of experimental methods to differentiate causal factors from correlates. We also discuss weaknesses in the experimental research, including limited work with non-WEIRD (western, educated, industrialized, rich and democratic) populations.     

Reproductive anatomy of three nulliparous female Asian elephants: The development of artificial breeding techniques

Detailed gross examinations of the reproductive tracts of three mature female nulliparous Asian elephants were conducted to develop artificial insemination (AI) techniques. Of primary concern was the determination of the length characteristics and the size and configuration of the foramina between segments of the tract. The elephants were 13, 28, and 40 years of age and had been maintained in captivity for most of their lives. One elephant died naturally and two were euthanized for health reasons. The reproductive tracts of two of the elephants were manually palpated in situ via the urogenital canal. A fibreoptoscope was used to visualize the internal structures of the terminal reproductive tract of one elephant and to deposit dye into the vagina. The reproductive organs were removed from the body cavity, dissected, measured, and photographed. The major anatomical obstacles to overcome for standard AI procedures (the passage of an AI pipette into the reproductive tract) were the length of the urogenital canal (85–97 cm), the constriction at the urogenital-vaginal junction, and the tight cervix. The reproductive anatomy was compared to that of previous dissections reported in the literature.     

Association of vegetative and reproductive organs of platanoids (Angiospermae): significance for systematics and phylogeny

Some examples of association between platanoid leaves and various reproductive structures are considered. The expediency of determining dispersed Cretaceous platanoid leaves using a morphological system that is independent of the system of modern plants is discussed. It is confirmed that leaf structures are more conservative than reproductive organs. It is proposed that, in the geological past, there was a polymorphic group that was probably represented by extinct families which gave rise to modern families (in particular, Platanaceae and Hamamelidaceae).     

延迟交配对昆虫生殖行为的影响以及与性信息素防治害虫的关系

对鳞翅目昆虫延迟交配对昆虫生殖力、卵孵化率、交配成功率、成虫寿命等进行了总结。雌虫延迟交配降低雌虫的生殖力、卵的孵化率及与雄虫成功交配率,但可以延长雌虫寿命。雄虫延迟交配降低雌虫的生殖力、卵的孵化率、产卵时间,雄虫的精子质量下降但寿命有所增加。已发现延迟交配在迷向法中控制害虫起着重要的作用,对进一步认识迷向法中不同作用机理以及延迟交配在迷向法防治害虫中的潜力进行了探讨。     

Novel Cellulase Profile of Trichoderma reesei Strains Constructed by cbh1 Gene Replacement with eg3 Gene Expression Cassette

The filamentous fungus Trichoderma reesei is consi-dered to be the most efficient cellulase producer, and hasa long history in the production of hydrolytic enzymes,which was widely used in the food and feed industriesand recently also used in the textile,…     

生长分化因子9基因的分子生物学

生长分化因子9是卵母细胞分泌的一种生长因子,它对卵泡的生长分化起着重要作用。本文介绍了生长分化因子9的结构、功能和调控,生长分化因子9基因的克隆及基因结构、发育性表达和作用、定位和多态性,并讨论了该基因与哺乳动物繁殖性能的关系。