Zerumbone induced apoptosis in liver cancer cells via modulation of Bax/Bcl-2 ratio

Background  

Zerumbone is a cytotoxic component isolated from Zingiber zerumbet Smith, a herbal plant which is also known as lempoyang. This new anticancer bioactive compound from Z. zerumbet was investigated for its activity and mechanism in human liver cancer cell lines.     

Identification of the gate regions in the primary structure of the secretin pIV

Secretins are a family of large bacterial outer membrane channels that serve as exit ports for folded proteins, filamentous phage and surface structures. Despite the large size of their substrates, secretins do not compromise the barrier function of the outer membrane, implying a gating mechanism. The region in the primary structure that forms the putative gate has not previously been determined for any secretin. To identify residues involved in gating the pIV secretin of filamentous bacteriophage f1, we used random mutagenesis of the gene followed by positive selection for mutants with compromised barrier function (‘leaky’ mutants). We identified mutations in 34 residues, 30 of which were clustered into two regions located in the centre of the conserved C‐terminal secretin family domain: GATE1 (that spanned 39 residues) and GATE2 (that spanned 14 residues). An internal deletion constructed in the GATE2 region resulted in a severely leaky phenotype. Three of the four remaining mutations are located in the region that encodes the N‐terminal, periplasmic portion of pIV and could be involved in triggering gate opening. Two missense mutations in the 24‐residue region that separates GATE1 and GATE2 were also constructed. These mutant proteins were unstable, defective in multimerization and non‐functional.     

耐甲氧西林金黄色葡萄球菌在动物流行病学中的研究进展

葡萄球菌是动物中重要的机会性病原体,耐甲氧西林金黄色葡萄球菌（MRSA）因其多药耐药的特征日益成为动物和公众健康的主要威胁。由于动物与动物及人畜间存在相互传染的风险,在控制MRSA感染的整个体系中,分析MRSA在动物中的流行显得尤为重要。     

中国岩黄芪属(豆科)植物资料增补

根据对标本的研究及文献资料的整理,证实了西伯利亚岩黄芪在中国的分布;山竹岩黄芪在新疆的分布新记录。另外,还报道了地中海岩黄芪在陕西的栽培记录。     

内蒙古植被枯黄期变化及其与气候和植被生产力的关系

基于2001—2018年MODIS NDVI数据,采用累计归一化植被指数(NDVI)的Logistic曲线曲率极值法,识别内蒙古植被枯黄期及其时空变化特征,并在生态区尺度上分析枯黄期对气候因子和NDVI的响应特征。结果表明: 研究期间,内蒙古植被平均枯黄期主要集中在第260～280天。森林生态区枯黄期为第270～280天,从南向北推迟;草原生态区枯黄期最早,介于第257～273天,从东北向西南逐渐推迟;荒漠生态区枯黄期为第270～283天,东北向西南呈推迟态势。2001—2018年间,3个生态区植被枯黄期均呈不显著推迟趋势。植被生产力从东北向西南逐渐降低,在时间上呈增加趋势的面积大于呈减小趋势的面积。全内蒙古和各生态区植被枯黄期受季前2～3个月降水量的正面影响较大,与季前平均温度、最高温度和最低温度均呈正相关关系。全内蒙古和各生态区,8和9月植被生产力的增加(或减少)将推迟(或提前)植被枯黄期,而6和7月植被生产力的增加(或减少)将提前(或推迟)草原和荒漠生态区植被枯黄期。     

叶绿素结合蛋白CP24介导光照响应基因StRSM 1调控叶绿素积累

单MYB转录因子成员RSM(RADIALIS-like SANT/MYB)突变,倒置黑暗诱导的叶绿素减少,原因有待确定;为了揭示RSM如何调控叶绿素积累,本研究运用基因工程途径,获得了普通烟草和马铃薯体内抑制和过量表达StRSM 1阳性转化株系,测定了阳性转化株系的叶绿素积累等生理表型;结果显示,普通烟草和马铃薯体内抑制RSM 1表达,显著增加了叶绿素积累,叶色随之加深;RSM 1过量表达,显著减少叶绿素积累,叶色变浅。叶绿素代谢相关基因表达测定结果显示,StRSM 1过量表达增加了黑暗下叶绿素结合蛋白CP24基因的表达,改变了其表达模式。以上结果表明,转录因子StRSM 1响应光照反向调控叶绿素积累,叶绿素结合蛋白CP24参与了StRSM 1对叶绿素积累的调控。结果有助于进一步明确RSM 1如何响应光照和深刻理解RSM 1参与的光照响应。     

Using microwave irradiation in Marchi's method for demonstrating degenerated myelin

Conventional methods for histological preparation of degenerated myelin are time-consuming and difficult. The purpose of our study was to shorten the time required for the procedure and to obtain better quality results for light microscopic demonstration of degenerated myelin in the central and peripheral nervous systems by using microwave irradiation. Rat brain and sciatic nerve were used for the study. The middle cerebral artery was occluded and the sciatic nerve was cut to produce myelin degeneration. Marchi's method was used for staining degenerated myelin. Fixation for light microscopy that would take two days using the conventional procedure was completed in 16.5–18.5 min using microwave irradiation. While staining of degenerated myelin requires 10 days for the conventional Marchi method, we decreased it to 7 h for brain tissue and 1 h for sciatic nerve by using the microwave oven. Moreover, a better quality preparation was achieved in the groups stained under microwave irradiation than those prepared by the conventional method.