Leaf morphology and cuticular features of Sphenophyllum in the Gigantopteris flora from South China

Permian specimens of Sphenophyllum with preserved cuticular anatomy have been discovered in Cathaysia and have prompted a detailed re-evaluation of the genus in the Gigantopteris flora in South China. New specimens are described and previously published material is re-examined to clarify taxonomic diversity and to establish geographic and stratigraphic ranges for each species. Recognized taxa include Sphenophyllum apiciserratum sp. nov., S. koboense Kobatake, S. meridionale sp. nov., S. minor (Sterzel) Gu and Zhi, S. sinocoreanum Yabe, S. cf. sinocoreanum Yabe, and S. aff. speciosum (Royle) McClelland. Cuticles of Sphenophyllum apiciserratum and S. koboense are hypostomatic with randomly disposed ordinary cells in intercostal regions. Specific concepts are clarified and unresolved taxonomic problems are discussed. The South China taxa are compared with those from Euramerican, Gondwanan and Angaran floras, and the South China Cathaysian species are found to be taxonomically distinct.     

Inherited human Caspase 10 mutations underlie defective lymphocyte and dendritic cell apoptosis in autoimmune lymphoproliferative syndrome type II.

Caspases are cysteine proteases that mediate programmed cell death in phylogenetically diverse multicellular organisms. We report here two kindreds with autoimmune lymphoproliferative syndrome (ALPS) type II, characterized by abnormal lymphocyte and dendritic cell homeostasis and immune regulatory defects, that harbor independent missense mutations in Caspase 10. These encode amino acid substitutions that decrease caspase activity and interfere with death receptor-induced apoptosis, particularly that stimulated by Fas ligand and TRAIL. These results provide evidence that inherited nonlethal caspase abnormalities cause pleiotropic apoptosis defects underlying autoimmunity in ALPS type II.     

白鲟消化道形态学与组织学的初步观察

白鲟消化道具有肉食性鱼类的典型特征,其口咽腔结构既适合捕食又适合吞食与滤食水生动物。咽后消化道可分为食道、胃后行支、胃前行支、小肠、瓣肠、直肠与肛门。幽门盲囊似一致密器官,小肠与瓣肠连接处有一特殊淋巴器官,肛门两侧有腹孔。白鲟口咽腔被覆层扁平上皮,上皮内有味蕾分布。咽后消化道组织分层为粘膜(无粘膜肌层)、粘膜下层(小肠及瓣肠前部无)、肌层与外膜。粘膜上皮为单层柱状上皮,由纤毛柱状细胞、一般柱状细胞和杯状细胞组成,其间还散在有颗粒细胞和游走细胞。食道后部与胃的一般柱状细胞为分泌粘液的细胞,肠内的一般柱状细胞为吸收细胞。胃后行支及部分前行支固有膜内有消化腺,其余各部的固有膜为致密层。小肠前中部粘膜形成蜂窝状粘膜窦,无肠腺。除食道前部肌层中有横纹肌外,其余部的肌层均为平滑肌。外膜内结缔组织有的致密有的疏松,外膜表面细胞柱状或立方形或扁平。     

基于功能性状的水杉原生母树种群生境适应策略

植物的功能性状变异和表型可塑性是其应对异质生境的主要机制, 对植物的生长和分布有重要贡献。本文以湖北星斗山国家级自然保护区的水杉(Metasequoia glyptostroboides)原生母树为研究对象, 分析了母树种群功能性状对树木形态、地形因子及人为干扰的响应机制。结果表明: 水杉原生母树叶面积、叶干重和比叶面积的变异幅度大, 可塑性较强, 而枝和叶的干物质含量稳定性最高。人为干扰和4个地形因子均对每个功能性状变异方差有5%-20%的解释度, 冠幅对枝、叶干物质含量的变异方差有高达38%和76%的解释度。5个功能性状主要受海拔、坡位和人为干扰影响, 其中, 比叶面积对环境因子和干扰的响应规律不明显, 叶面积和叶干重在强烈人为干扰的环境中普遍增大, 枝和叶的干物质含量对坡向的变化最敏感。总之, 水杉原生母树种群通过功能性状变异对环境能产生一定的可塑性响应, 但人为干扰对母树生长影响较大, 建议人工辅助更新, 并适度减少农业和建筑对现存母树的影响。     

绿盲蝽P450基因的克隆及增效醚对P450酶活性的抑制作用

为探讨P450介导的绿盲蝽Apolygus lucorum(Meyer-Dür)抗药性机制,合理使用杀虫药剂,本研究通过活体和离体抑制实验发现,增效醚(PBO)对绿盲蝽P450酶活性有显著的抑制作用:在处理时长为24h时,P450酶活性由未处理时的12.02pmol/min/mgPro.下降至1.63pmol/min/mgPro.,PBO对P450酶的抑制中浓度为0.256mmol/L。生物测定结果表明,PBO对三氟氯氰菊酯具有显著增效作用,增效7.2倍,而对吡虫啉、灭多威、马拉硫磷无显著增效作用。利用RT-PCR及RACE技术对绿盲蝽P450基因进行克隆,获得了2条CYP4家族基因,全长均为1631bp,含有完整的开放阅读框,编码501个氨基酸;序列比对表明这是一对等位基因,含有CYP4家族所有保守特征序列;同源性比较及系统发育分析显示这2个基因编码的氨基酸序列与褐飞虱Nilaparvata lugens CYP4CE1亲缘关系最近,同源性分别为41.5%和41.1%。     

微核技术研究进展

微核试验作为检测染色体损伤最常用而有效的细胞遗传学检测方法之一,经济、简便、快速,在敏感性、特异性和准确性方面,与经典的染色体畸变分析方法基本相当。主要综述国内外微核检测技术的最新研究进展,尤其是微核的自动化检测技术。其中流式细胞仪自动化检测和激光扫描细胞仪自动化检测,以及微核试验高内涵筛选方法由于其特有的优势,应用和发展前景广阔。     

Tim-3 pathway controls regulatory and effector T cell balance during hepatitis C virus infection

Hepatitis C virus (HCV) is remarkable at disrupting human immunity to establish chronic infection. Upregulation of inhibitory signaling pathways (such as T cell Ig and mucin domain protein-3 [Tim-3]) and accumulation of regulatory T cells (Tregs) play pivotal roles in suppressing antiviral effector T cell (Teff) responses that are essential for viral clearance. Although the Tim-3 pathway has been shown to negatively regulate Teffs, its role in regulating Foxp3(+) Tregs is poorly explored. In this study, we investigated whether and how the Tim-3 pathway alters Foxp3(+) Treg development and function in patients with chronic HCV infection. We found that Tim-3 was upregulated, not only on IL-2-producing CD4(+)CD25(+)Foxp3(-) Teffs, but also on CD4(+)CD25(+)Foxp3(+) Tregs, which accumulate in the peripheral blood of chronically HCV-infected individuals when compared with healthy subjects. Tim-3 expression on Foxp3(+) Tregs positively correlated with expression of the proliferation marker Ki67 on Tregs, but it was inversely associated with proliferation of IL-2-producing Teffs. Moreover, Foxp3(+) Tregs were found to be more resistant to, and Foxp3(-) Teffs more sensitive to, TCR activation-induced cell apoptosis, which was reversible by blocking Tim-3 signaling. Consistent with its role in T cell proliferation and apoptosis, blockade of Tim-3 on CD4(+)CD25(+) T cells promoted expansion of Teffs more substantially than Tregs through improving STAT-5 signaling, thus correcting the imbalance of Foxp3(+) Tregs/Foxp3(-) Teffs that was induced by HCV infection. Taken together, the Tim-3 pathway appears to control Treg and Teff balance through altering cell proliferation and apoptosis during HCV infection.     

Stromal cell-derived factor 1 (SDF-1) and its receptor CXCR4 improves diabetic retinopathy

Diabetes induced a serious of complications including diabetic retinopathy. Our study aimed to investigate the role of Stromal cell-derived factor 1 (SDF-1) and its receptor CXCR4 in diabetic retinopathy. A mice model of diabetic retinopathy was established, and expression of SDF-1 and CXCR4 in retina was examined by Real-time quantitative PCR (qRT-PCR). Cells of human retinal pigment epithelial cell line ARPE-19 were treated with CXCR4 siRNAs and expression vector, and cell viability was detected by MTT assay. We found that expression of SDF-1 and CXCR4 in retina was significantly downregulated in mice with diabetic retinopathy than in normal healthy mice. High glucose treatment downregulated the expression of SDF-1 and CXCR4 in ARPE-19 cells at both mRNA and protein levels. Transfection with CXCR4 siRNAs decreased, while transfection with CXCR4 expression vector increased cell viability under high glucose treatment. We concluded that SDF-1/CXCR4 pathway improved diabetic retinopathy possibly by increasing cell viability.

Abbreviations: SDF-1: Stromal cell-derived factor 1; CXCL12: C-X-C motif chemokine 12; qRT-PCR: Real-time quantitative PCR