氧化应激与自噬

自噬是细胞依赖溶酶体对蛋白质和细胞器进行降解的过程,能帮助细胞适应各种不良刺激,在维持细胞内环境稳态和实现自我更新中起着重要作用。氧化应激是机体氧化和抗氧化系统之间的稳态被破坏而造成的应激状态。大量研究表明,氧化应激中产生的活性氧能诱导自噬产生,而自噬能缓解氧化应激造成的损伤,从而保护细胞存活。本文主要对自噬的形成过程、氧化应激诱导自噬产生机制以及自噬缓解氧化应激的途径等进行综述,以期为畜牧生产中通过调控自噬缓解氧化应激提供理论依据。     

完全雄性柿种质‘雄株8号’作为中国甜柿育种亲本的可能性研究

‘雄株8号’是中国中部大别山区分布的完全雄性柿种质,可能源自中国原产完全甜柿(中国甜柿)的杂交后代或是其自然变异,其作为完全甜柿专用授粉品种的可能性已有研究报道,但其作为完全甜柿育种亲本的应用潜力尚不明确。以‘华柿1号’(不完全涩柿)ב雄株8号’的杂交后代单株为试材,以常见中国甜柿、日本甜柿和非完全甜柿为对照,对其果实进行可溶性和不溶性单宁含量、单宁细胞大小等指标测定,确认杂交后代单株H8-2为具中国甜柿自然脱涩特点的完全甜柿类型。现有完全甜柿自然脱涩性状遗传特点的研究结果认为,只有日本甜柿相互杂交,或者是亲本之一为中国甜柿时,F_1才可能出现完全甜柿单株。该研究结果首次证明中国原产完全雄性柿种质‘雄株8号’带有控制自然脱涩性状的显性基因,因此其在完全甜柿遗传改良中具有作为育种亲本的应用潜力。     

Effects of all-trans retinoic acid on sensitivity of gastric cancer cells to radiotherapy

AIM: To investigate the effect of all-trans retinoic acid (ATRA) on the viability of gastric cancer cell SGC-7901 and the sensitivity to radiotherapy. METHODS: MTT assay was used to examine the cell viability. Radio-sensitivity and cell cycle were determined by colony formation assay and flow cytometry, respectively. The mRNA levels of Bax, Bcl-2, survivin and NF-κB in the cells were measured by RT-qPCR. RESULTS: ATRA inhibited the viability of SGC-7901 cells in a concentration-dependent manner. The maximal inhibition was at concentration of 8 μmol/L. Colony formation assay revealed that the combination of ATRA with X-ray treatment significantly reduced the values of D0 and Dq, and shifted down the fitting survival curve, as compared with radiotherapy alone. Moreover, ATAR markedly decreased the percentage of G₂/M phase in the SGC-7901 cells (P<0.05). In addition, following ATRA treatment, the mRNA levels of Bcl-2 and survivin were decreased (P<0.05), whereas the mRNA levels of Bax and NF-κB were increased (P<0.05). CONCLUSION: ATRA enhances the sensitivity of SGC-7901 cells to radiotherapy, inhibits G₂/M arrest and regulates the mRNA expression of Bax, Bcl-2, survivin and NF-κB.     

Ultrasound‐guided lipoaspiration for mesenchymal stromal cell harvest in the horse

Mesenchymal stromal cells (MSC) are being used to treat a variety of conditions in the horse. Traditional lipectomy and bone marrow aspiration for MSC harvest have disadvantages including cosmetic issues with lipectomy and extensive time for cell expansion after bone marrow harvests. This article describes a new technique of adipose harvest in the horse, utilising ultrasound and liposuction that can be safely and effectively performed in an ambulatory environment. Ultrasound‐guided lipoaspiration offers a minimally invasive technique using small portals and a diffuse area of collection significantly improving aesthetic outcome and increasing the likelihood of treating within a matter of days vs. a matter of weeks.     

线粒体与种子老化的关系

种子作为最基本的生产资料,其活力高低直接关系到农业生产的成败。关于种子老化机理的研究是种子科学研究的热点和难点。线粒体是真核生物细胞内重要的细胞器,是细胞能量合成和物质代谢的中心,也是活性氧产生的主要位点,且普遍认为,活性氧是导致种子老化的主要因素。种子老化过程中线粒体的典型结构逐渐被破坏,呼吸速率和氧化磷酸化效率降低,抗氧化功能发生改变,因此,本文主要概述种子的老化与线粒体结构、呼吸作用、抗氧化系统变化的关系,并阐述线粒体与细胞程序性死亡关系的研究进展,系统分析种子老化与线粒体变化研究中存在的问题及未来发展趋势,以期为研究种子老化的线粒体作用机理提供理论基础。     

The biological and practical significance of antigenic variability in protective T cell responses against Theileria parva

The evolution of antigenically distinct pathogen strains that fail to cross-protect is well documented for pathogens controlled primarily by humoral immune responses. Unlike antibodies, which recognise native proteins, protective T cells can potentially recognise epitopes in a variety of proteins that are not necessarily displayed on the pathogen surface. Moreover, individual hosts of different MHC genotypes generally respond to different sets of epitopes. It is therefore less easy to envisage how strain restricted immunity can arise for pathogens controlled by T cell responses, particularly in antigenically complex parasites. Nevertheless, strain restricted immunity is clearly a feature of a number of parasitic infections, where immunity is known to be mediated by T cell responses. One such parasite is Theileria parva which induces potent CD8 T cell responses that play an important role in immunity. CD8 T cells specific for parasitized lymphoblasts exhibit strain specificity, which appears to correlate with the ability of parasite strains to cross-protect. Studies using recently identified T. parva antigens recognised by CD8 T cells have shown that the strain restricted nature of immunity is a consequence of the CD8 T cell response in individual animals being focused on a limited number of dominant polymorphic antigenic determinants. Responses in animals of different MHC genotypes are often directed to different parasite antigens, indicating that, at the host population level, a larger number of parasite proteins can serve as targets for the protective T cell response. Nevertheless, the finding that parasite strains show overlapping antigenic profiles, probably as a consequence of sexual recombination, suggests that induction of responses to an extended but limited set of antigens in individual animals may overcome the strain restricted nature of immunity.     

Molecular cloning and expression analysis of pig CD81

CD81, also known as TAPA-1 (target of antiproliferative antibody 1), is a member of the tetraspanin family of proteins and a component of the B cell co-receptor complex. Several studies have shown that CD81 plays significant roles in a variety of immune responses, including activation of B cells and T cells. In this study, we cloned pig Cd81 cDNA using RT-PCR coupled with rapid amplification of cDNA ends (RACE)-PCR and determined the complete cDNA sequence of pig Cd81. Pig Cd81 cDNA contains an open reading frame (711 bp) encoding 236 amino acids. The identity of pig CD81 with those of human, cattle, rat, and mouse are 90.30%, 92.26%, 86.22%, and 86.22%, respectively. Alignment of the CD81 amino acid sequence with those of mammalian species showed that the large extracellular loop (LEL) is the most divergent, whereas other domains are largely conserved. Pig Cd81 mRNA was detected by RT-PCR in a broad range of tissues, including lymphoid tissues as well as nonlymphoid tissues, indicated variety of cellular functions of CD81 in most pig tissues. Flow cytometry analyses demonstrated that human CD81 antibody recognizes a pig CD81 on the cell surface. Further, immunohistochemistry analysis using human CD81 antibody on pig spleen was revealed that CD81 expression is widely diffused in spleen tissue. Future study will be focused on defining the functional role of CD81 during the course of pig infectious diseases.     

多花黑麦草抽穗期干物质体外消化率在品系间的差异

研究了不同熟期类型多花黑麦草品系的抽穗期干物质产量、干物质体外消化率 (IVDMD)以及细胞壁结构物质含量和消化率与IVDMD的相关性,结果表明:①不同熟期类型间IVDMD存在显著差异,其中极早熟类型和早熟类型极显著高于晚熟类型和中熟类型,晚熟类型又极显著高于中熟类型;相同熟期类型品系间,只有中熟类型的IVDMD差异显著。②极早熟类型和早熟类型的半纤维素含量以及中熟类型和晚熟类型的纤维素含量与IVD MD呈极显著负相关关系;所有熟期类型的半纤维素消化率以及晚熟类型纤维素消化率与IVDMD分别呈极显著和显著的正相关关系。     

僵藕的发病症状及细胞结构

观察研究了僵藕的形态特征和茎叶细胞的超微结构。结果表明:僵藕藕身表面出现棕褐色斑点、条斑,表皮细胞和薄壁细胞常被破坏形成空腔,薄壁细胞中淀粉粒减少,维管束衰退,导管发育不全,筛管内含物积聚,运输功能受损;叶绿体和线粒体结构混乱,膜解体、消失,细胞核核膜不清,核仁不明显;液泡内含物聚集;僵藕病叶叶肉细胞和叶脉细胞中有6~8臂的风轮状内含体,同时在僵藕病叶组织的粗提取液中发现线条状病毒粒子。     

花生荚果发育过程中子叶贮藏细胞的形态变化及其与油分和蛋白质积累的关系

花生荚果发育过程中,子叶贮藏细胞的形态和结构皆发生一系列明显的变化。果针入土0-30天,子叶贮藏细胞不断形成分化,体积变化较小,细胞中脂体和蛋白体形成少,而造粉体则形成较多,并大量积累淀粉粒。果针入土30-45天,子叶贮藏细胞迅速生长,脂体、蛋白体大量形成和增大,充满整个细胞。而淀粉粒形成少。果针入土45-68天,子叶细胞生长减慢,脂体则进一步发育,蛋白体持续形成和增大,60天以后蛋白体趋于解体,间质充挤于脂体间隙。未期,子叶细胞停止膨大,并可能因失水而体积略有减小。结果表明,花生子叶细胞的生长发育,是种仁和荚果形态发育的基础;种仁油分和蛋白质的积累则是其体内脂体和蛋白体不断形成和发育的结果。