毛竹的花药发育研究

竹类植物因有着较长的开花周期,其生殖生物学研究的报道相对较少。该研究采用石蜡切片与野外观察的方法,对毛竹花药的发育以及花药发育与花序的关系进行了研究。结果表明:毛竹的花药壁结构包括4层细胞:表皮细胞、药室内壁细胞、中层细胞和绒毡层细胞。药室内壁和中层都只有一层细胞,而且细胞形状较扁,花药发育后期药室内壁会逐渐降解,而中层则会完全解体消失。花药壁的发育为单子叶型,绒毡层为腺质型,而且只有一层,细胞径向较长,最后也会消失。小孢子母细胞减数分裂时,胞质分裂方式为连续型。形成的小孢子经一次有丝分裂后逐渐形成成熟花粉粒,大多为二细胞型,很少产生三细胞型。此外,还发现毛竹花药的发育与花序形态变化存在着相对应的关系。野外连续观察和切片发现,随着花序形态的不断发育变化,首先花药开始形成并不断分化,药壁备层也逐渐形成;接着小孢子逐渐成熟,备层也慢慢随之解体、消失;最后花药逐渐开裂并开始散粉。该研究结果不仅丰富了毛竹和竹类生殖生物学的研究内容,而且对毛竹种质的研究也具有重要意义。     

小球藻细胞壁缺陷型突变体的筛选及转化系统的建立

由于高效、稳定遗传转化系统的缺乏,小球藻遗传改良以及油脂代谢机理的研究等工作难以进行。研究旨在通过筛选获得小球藻Chlorella vulgaris细胞壁缺陷型突变体,在此基础上建立其转化系统。首先通过紫外诱变获得小球藻Chlorella vulgaris的突变体库,基于细胞壁缺陷型突变体在1% Triton X-100处理后叶绿素会释放到上清中的原理,利用酶标仪高通量地从约4000个突变体中筛选获得10株细胞壁缺陷的小球藻。同时以小球藻内源性-tubulin的启动子和终止子作为启动子和终止子,以AphⅧ (Aminoglycoside 3'-Phosphotransferase type Ⅷ)作为报告基因构建了转化载体pHK203。通过优化电转缓冲液组分和电击参数,确定了细胞壁缺陷型突变体CWD-3的最佳转化条件,即2 g pHK203,ddH2O作为电转缓冲液,1500 V,525 ,50 F的电击条件下,转化效率可达到40个转化子/g DNA。研究为小球藻Chlorella vulgaris的油脂代谢通路和遗传改良提供了技术基础,同时由于可降低破壁成本,筛选获得的细胞壁缺陷型突变体适于工业化生产小球藻藻粉。     

Three-dimensional macro-scale assessment of regional and temporal wall shear stress characteristics on aortic valve leaflets

The aortic valve (AV) achieves unidirectional blood flow between the left ventricle and the aorta. Although hemodynamic stresses have been shown to regulate valvular biology, the native wall shear stress (WSS) experienced by AV leaflets remains largely unknown. The objective of this study was to quantify computationally the macro-scale leaflet WSS environment using fluid–structure interaction modeling. An arbitrary Lagrangian–Eulerian approach was implemented to predict valvular flow and leaflet dynamics in a three-dimensional AV geometry subjected to physiologic transvalvular pressure. Local WSS characteristics were quantified in terms of temporal shear magnitude (TSM), oscillatory shear index (OSI) and temporal shear gradient (TSG). The dominant radial WSS predicted on the leaflets exhibited high amplitude and unidirectionality on the ventricularis (TSM>7.50 dyn/cm², OSI < 0.17, TSG>325.54 dyn/cm² s) but low amplitude and bidirectionality on the fibrosa (TSM < 2.73 dyn/cm², OSI>0.38, TSG < 191.17 dyn/cm² s). The radial WSS component computed in the leaflet base, belly and tip demonstrated strong regional variability (ventricularis TSM: 7.50–22.32 dyn/cm², fibrosa TSM: 1.26–2.73 dyn/cm²). While the circumferential WSS exhibited similar spatially dependent magnitude (ventricularis TSM: 1.41–3.40 dyn/cm², fibrosa TSM: 0.42–0.76 dyn/cm²) and side-specific amplitude (ventricularis TSG: 101.73–184.43 dyn/cm² s, fibrosa TSG: 41.92–54.10 dyn/cm² s), its temporal variations were consistently bidirectional (OSI>0.25). This study provides new insights into the role played by leaflet–blood flow interactions in valvular function and critical hemodynamic stress data for the assessment of the hemodynamic theory of AV disease.     

基于定量蛋白质组学的NT-89抗白念珠菌作用机制研究

目的利用定量蛋白质组学iTRAQ技术,分析抗真菌化合物NT-89作用后白念珠菌蛋白质组的含量变化。方法提取NT-89作用前后的白念珠菌总蛋白与细胞壁蛋白,利用iTRAQ技术检测蛋白提取物中蛋白质的相对丰度,寻找药物作用前后的差异蛋白,并利用GO数据库注释蛋白质功能分类。结果总蛋白(TP)提取物中检测出295种差异蛋白,其中的Ywp1p、Pga10p在总蛋白中含量下调最为显著。细胞壁蛋白(CWP)提取物中有6种GPI锚定蛋白含量显著降低。结论 NT-89影响了白念珠菌细胞壁的结构完整与功能,iTRAQ技术能够为药物的作用机制研究提供有效参考信息。     

凝溶胶蛋白基因的生物学功能及其应用研究进展

凝溶胶蛋白(gelsolin,GSN)是Gelsolin/Villin超家族的核心成员,是一种多功能的钙依赖性肌动蛋白结合蛋白,在细胞中Ca^2+和PIP2等多因素的调控下,对细胞凋亡、吞噬功能、肌动蛋白微丝切割、细胞信号转导等方面起着重要的作用。近年来,凝溶胶蛋白还被频繁用于相关疾病的预防、诊断与治疗,但其在调控细胞凋亡、炎症等病理生理中的作用机制还存在些许争议。本研究综述了凝溶胶蛋白的结构特点、生物学功能以及对疾病的诊断和治疗,旨在了解凝溶胶蛋白在生物医学及动物科学等领域的应用以及未来凝溶胶蛋白的发展前景。     

Suitability of tomato leaves for larval development of Potato Tuber Moth,Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae)

The potato tuber moth (PTM) is an important pest of the potato plant and its tuber. With the expansion of its geographic range, the PTM could be potential threat to the tomato (Solanum lycopersicum L.), a congeneric species of the potato. To assess that risk, we tested larval feeding and development of PTM on leaves of five cultivated tomato varieties namely Moneymaker, Campari, Ailsa Craig, LA3475, E6203 and one wild tomato variety S. pimpinellifolium. PTM larvae accepted all tested plant leaves and developed into adults. Larval development was fastest on the Ailsa Craig variety. Pupae developed fastest on the Moneymaker variety and slowest on LA3475. Host acceptance and survival were highest on Ailsa Craig and lowest on LA3475. The significantly highest male proportion occurred on LA3475 variety. The study showed that PTM could be a potential threat to tomato cultivation which is rapidly increasing in temperate regions owing to climate change.     

PARP-1 and its associated nucleases in DNA damage response

Poly(ADP-ribose) (PAR) polymerase-1 (PARP-1) acts as a DNA damage sensor. It recognizes DNA damage and facilitates DNA repair by recruiting DNA repair machinery to damage sites. Recent studies reported that PARP-1 also plays an important role in DNA replication by recognizing the unligated Okazaki fragments and controlling the speed of fork elongation. On the other hand, emerging evidence reveals that excessive activation of PARP-1 causes chromatin DNA fragmentation and triggers an intrinsic PARP-1-dependent cell death program designated parthanatos, which can be blocked by genetic deletion or pharmacological inhibition of PARP-1. Therefore, PARP-1 plays an essential role in maintaining genomic stability by either facilitating DNA repair/replication or triggering DNA fragmentation to kill cells. A group of structure-specific nucleases is crucial for executing DNA incision and fragmentation following PARP-1 activation. In this review, we will discuss how PARP-1 coordinates with its associated nucleases to maintain genomic integrity and control the decision of cell life and death.     

The inflammatory mediators TNFα and nitric oxide arrest spermatogonia GC-1 cell cycle

During an inflammatory process of the testis, the network of somatic, immune, and germ cell interactions is altered leading to organ dysfunction. In testicular biopsies of infertile men, spermatogenesis impairment is associated with reduced spermatogonia proliferation, increased number of immune cells, and content of pro-inflammatory cytokines. TNFα-TNFR and nitric oxide (NO)-NO synthase systems are up-regulated in models of testicular damage and in human testis with maturation arrest. The purpose of this study was to test the hypothesis that TNFα-TNFR system and NO alter the function of spermatogonia in the inflamed testis. We studied the effect of TNFα and NO on GC-1 spermatogonia cell cycle progression and death by flow cytometry. GC-1 cells expressed TNFR1 and TNFR2 (immunofluorescence). TNFα (10 and 50 ng/ml) and DETA-Nonoate (0.5 and 2 mM), a NO releaser, increased the percentage of cells in S-phase of the cell cycle and reduced the percentage in G1, inducing also cell apoptosis. TNFα effect was not mediated by oxidative stress unlike NO, since the presence of N-acetyl-l-cysteine (2.5 and 5.0 mM) prevented NO induced cell cycle arrest and death. GC-1 spermatogonia overpass NO induced cell cycle arrest but no TNFα, since after removal of NO, spermatogonia progressed through the cell cycle. We propose TNFα and NO might contribute to impairment of spermatogenesis by preventing adequate functioning of the spermatogonia population. Our results showed that TNFα and NO impaired spermatogonia cell cycle, inducing GC-1 arrest in the S phase.     

Organelle aging:Lessons from model organisms

Most cellular processes descend into failure during aging. While a large collection of longevity pathways has been identified in the past decades, the mechanism for age-related decline of cellular homeostasis and organelle function remains largely unsolved. It is known that many organelles undergo structural and functional changes during normal aging, which significantly contributes to the decline of tissue function at old ages. Since recent studies have revealed an emerging role of organelles as regulatory hubs in maintaining cellular homeostasis, understanding of organelle aging will provide important insights into the cellular basis of organismal aging. Here we review current progress on the characterization of age-dependent structural and functional alterations in the more well-studied organelles, as well as the known mechanisms governing organelle aging in model organisms, with a special focus on the fruit fly Drosophila melanogaster.     

BioID Performed on Golgi Enriched Fractions Identify C10orf76 as a GBF1 Binding Protein Essential for Golgi Maintenance and Secretion

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Highlights

• •BioID with Golgi fractions identified C10orf76 as proximal to GBF1.
• •Tagged C10orf76 overlaps with Golgi markers.
• •C10orf76 binds GBF1 and exchanges rapidly between free and bound forms.
• •C10orf76 is essential for maintenance of the Golgi and for secretion.