猪圆环病毒Ⅱ型流行病学新特点及致病机理研究进展

猪圆环病毒是猪圆环病毒病的主要致病因素,该病给养猪业带来很大的经济损失。猪圆环病毒变异较快,是单链DNA病毒中最高的;易感猪主要通过消化道和呼吸道水平传播而感染,猪圆环病毒Ⅱ型(PCV2)人工或自然感染猪的排泄物、鼻腔、口腔和扁桃体拭子和患畜的尿液和粪便中均能检测到PCV2。断奶仔猪多系统衰竭综合征(PMWS)的发病主要与猪体内PCV2含量有关。PCV2特异抗体对猪群的PCV2感染具有保护作用。PCV2诱导猪继发性免疫缺陷,淋巴细胞缺失,影响PCV2感染结果的因素有:病毒、宿主、混合感染和免疫调节等。     

高致病性猪繁殖与呼吸综合征的诊断与防治

高致病性猪繁殖与呼吸综合征是由PRRSV变异株引起的一种急性高致病性传染病,近些年给养猪业造成巨大的损失。文章就高致病性猪繁殖与呼吸综合征的最新流行特点、诊断、防治等方面予以介绍。     

猪圆环病毒2型感染对猪繁殖与呼吸综合征灭活疫苗体液免疫的影响

本试验采用ELISA方法对单独接种猪繁殖与呼吸综合征病毒(PRRSV)变异株灭活苗组(HP组,n=3)和PCV2感染且出现病毒血症后接种PRRSV变异株灭活苗组(PCV2/HP组,n=3)不同时相血清中的PRRSV抗体进行检测;并对HP和PCV2/HP组血清中PCV2特异的抗体和核酸分别进行ELISA和荧光定量PCR检测。结果表明,在首免后70 d HP组血清平均抗体效价极显著高于PCV2/HP组(P<0.01);首免后56、63和77 d HP组平均抗体效价明显高于PCV2/HP组。其中在首免后56和63 d HP组抗体阳性率均达67%(2/3),PCV2/HP组在相应时相抗体阳性率为0;在首免后70和77 d HP组抗体阳性率均达100%(3/3),PCV2/HP组在相应时相抗体阳性率仅为0和33%(1/3)。结果提示PCV2感染可在一定程度上抑制PRRSV变异株(JXA1)特异性的抗体反应。     

套式PCR在猪流行性腹泻病毒感染病例诊断中的应用

猪流行性腹泻是对养猪业危害较大的一种疾病,导致腹泻的原因多种多样,给临床诊断带来了困难。本研究将套式PCR技术成功应用于猪流行性腹泻临床病例的快速诊断中,旨在为猪流行性腹泻临床病例的快速鉴别诊断提供一种新的思路。     

黑豆根尖边缘细胞对盐胁迫的防护效应

采用振荡培养(移除根尖边缘细胞)和静置培养(保持边缘细胞附着在根尖)方法,对比研究盐胁迫对黑豆根系生长和根尖边缘细胞发育、根系Na+、K+含量的影响以及根系生理特性的变化。结果显示:100和200 mmol.L-1NaCl处理抑制边缘细胞发育,引起根系相对电导率和MDA含量增加。振荡培养去除根尖边缘细胞处理36 h,黑豆根相对伸长率、根尖K+含量明显低于对应NaCl浓度的静置培养处理,同时根尖Na+含量、相对电导率和MDA含量在去除边缘细胞后显著增加。说明包裹于根尖的边缘细胞通过调节Na+和K+的吸收和维持较高的细胞膜完整性,以适应盐害环境。     

Anti-melanogenic property of geoditin A in murine B16 melanoma cells

Geoditin A, an isomalabaricane triterpene isolated from marine sponge Geodia japonica, has been demonstrated to induce apoptosis in leukemia HL60 cells and human colon HT29 cancer cells through an oxidative stress, a process also interfering with normal melanogenesis in pigment cells. Treatment of murine melanoma B16 cells with geoditin A decreased expression of melanogenic proteins and cell melanogenesis which was aggravated with adenylate cyclase inhibitor SQ22536, indicating melanogenic inhibition was mediated through a cAMP-dependent signaling pathway. Immunofluorescence microscopy and glycosylation studies revealed abnormal glycosylation patterns of melanogenic proteins (tyrosinase and tyrosinase-related protein 1), and a co-localization of tyrosinase with calnexin (CNX) and lysosome-associated membrane protein 1 (LAMP-1), implicating a post-translational modification in the ER and a degradation of tyrosinase in the lysosome. Taken together, potent anti-melanogenic property and the relatively low cytotoxicity of geoditin A have demonstrated its therapeutic potential as a skin lightening agent.     

Antiproliferative Activity of Fucan Nanogel

Sulfated fucans comprise families of polydisperse natural polysaccharides based on sulfated L-fucose. Our aim was to investigate whether fucan nanogel induces cell-specific responses. To that end, a non toxic fucan extracted from Spatoglossum schröederi was chemically modified by grafting hexadecylamine to the polymer hydrophilic backbone. The resulting modified material (SNFuc) formed nanosized particles. The degree of substitution with hydrophobic chains was close to 100%, as estimated by elemental analysis. SNFfuc in aqueous media had a mean diameter of 123 nm and zeta potential of −38.3 ± 0.74 mV, as measured by dynamic light scattering. Nanoparticles conserved their size for up to 70 days. SNFuc cytotoxicity was determined using the MTT assay after culturing different cell lines for 24 h. Tumor-cell (HepG2, 786, H-S5) proliferation was inhibited by 2.0%–43.7% at nanogel concentrations of 0.05–0.5 mg/mL and rabbit aorta endothelial cells (RAEC) non-tumor cell line proliferation displayed inhibition of 8.0%–22.0%. On the other hand, nanogel improved Chinese hamster ovary (CHO) and monocyte macrophage cell (RAW) non-tumor cell line proliferation in the same concentration range. The antiproliferative effect against tumor cells was also confirmed using the BrdU test. Flow cytometric analysis revealed that the fucan nanogel inhibited 786 cell proliferation through caspase and caspase-independent mechanisms. In addition, SNFuc blocks 786 cell passages in the S and G2-M phases of the cell cycle.     

Induction of Apoptosis by Sinulariolide from Soft Coral through Mitochondrial-Related and p38MAPK Pathways on Human Bladder Carcinoma Cells

Sinulariolide, an isolated compound from the soft coral Sinularia flexibilis, possesses the anti-proliferative, anti-migratory and apoptosis-inducing activities against the TSGH bladder carcinoma cell. The anti-tumor effects of sinulariolide were determined by 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, cell migration assay and flow cytometry, respectively. Sinulariolide inhibited the growth and migration of bladder carcinoma cells in a dose-dependent manner, as well as induced both early and late apoptosis as determined by the flow cytometer. Also, the sinulariolide-induced apoptosis is related to the mitochondrial-mediated apoptosis via caspase-dependent pathways, elucidated by the loss of mitochondrial membrane potential, release of cytochrome C, activation of caspase-3/-9, Bax and Bad, as well as suppression of Bcl-2/Bcl-xL/Mcl-1. Detection of the PARP-1 cleaved product suggested the partial involvement of caspase-independent pathways. Moreover, inhibition of p38MAPK activity leads to the rescue of the cell cytotoxicity of sinulariolide-treated TSGH cells, indicating that the p38MAPK pathway is also involved in the sinulariolide-induced cell apoptosis. Altogether, these results suggest that sinulariolide induces apoptosis against bladder cancer cells through mitochondrial-related and p38MAPK pathways.     

体外诱导牛骨髓间充质干细胞向乳腺样上皮细胞分化的初步研究

为培育转基因肉牛提供种子细胞及进一步丰富牛骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSC)的多向分化潜能,本试验利用细胞免疫荧光染色方法和分子生物学方法初步探讨在表皮生长因子、胰岛素、催产素和孕酮等条件下,体外诱导牛BMSC向乳腺样上皮细胞分化的可能性。利用不同浓度的诱导液对纯化稳定的P4、P8和P12代牛BMSC进行体外诱导,并对诱导后的细胞进行细胞免疫荧光观察和RT-PCR鉴定。结果显示,诱导后部分BMSC细胞呈多角形,而不再呈明显的梭形和纺锤形,经细胞角蛋白18免疫荧光染色后出现明显的荧光。P4代牛BMSC在诱导液Ⅱ的诱导作用下分化效果显著。RT-PCR结果显示,诱导分化后细胞角蛋白19基因、β-酪蛋白基因及αs1-酪蛋白基因在细胞中表达。因此,在体外,多因子联合诱导可使牛BMSC初步分化为乳腺样上皮细胞并且在诱导液Ⅱ的联合诱导下分化作用最明显。     

猪孤雌激活早期胚胎线粒体分布及mtDNA拷贝数变化的研究

本研究通过线粒体分子探针标记技术检测孤雌激活早期胚胎线粒体的分布变化,运用实时荧光定量PCR技术检测mtDNA拷贝数的变化,揭示早期胚胎发育过程中线粒体分布、mtDNA拷贝数变化趋势。结果表明,成熟卵母细胞电激活后,由2-细胞胚胎开始,卵裂球内线粒体分布均匀且密集,每个细胞均有分布,卵裂球之外的空隙未见线粒体分布,直到囊胚形成,线粒体均有分布。孤雌激活4-细胞胚胎mtDNA拷贝数显著高于8-细胞胚胎mtDNA拷贝数(907210.77±145520.77,186224.33±103308.00,P<0.05),但显著低于2-细胞胚胎、桑椹胚、囊胚的mtDNA拷贝数(1563422.54±224666.51、1697626.25±176999.53和1752301.29±101146.64,P<0.05)。孤雌激活扩张囊胚mtDNA拷贝数最高,为2812545.67±156819.31,显著高于其他发育时期胚胎的mtDNA拷贝数(P<0.05)。由此可见,孤雌激活早期胚胎发育进程中线粒体分布及mtDNA拷贝数会发生变化。