云南含笑花粉萌发研究

应用离体培养和人工授粉的方法对云南含笑花粉的萌发进行了研究。栽培和野生云南含笑花粉的萌发率有很大的差异,分别为20％和90％。首次报道了云南含笑的花粉粒在离体培养基上萌发2条花粉管的现象。云南含笑花粉在灰岩含笑花柱头上的萌发率和萌发时间与离体培养基上的相同,表明灰岩含笑的柱头对云南含笑的花粉没有排异现象。     

用cDNA微阵列技术快速筛选粗毛栓菌的表达基因(英)

利用cDNA微阵列技术快速筛选具有较强降解木质纤维素能力的白腐真菌粗毛栓菌(Trametes gallica)的表达基因.利用木质素生物降解模式菌株黄孢原毛平革菌（Phanerochaete chrysosporium）的cDNA制备研究所用微阵列.在含有2 596个cDNA片段的芯片上共检测到172个阳性克隆,其中有165个克隆的荧光信号比值（Cy-5/Cy-3）在0.5和2.0之间,占所检测阳性克隆数的95.9％.对应于在限氮条件下生长５天和12天的粗毛栓菌培养物,分别有３个和４个时序特异性差异表达基因.随机挑取122个克隆进行测序和序列比对,发现所测序列中有118个能够很好地定位于黄孢原毛平革菌的基因组上.结果显示,粗毛栓菌与黄孢原毛平革菌在表达序列上存在较大差异,表明这两种真菌之间存在着较远的亲缘关系.通过同源性比对分析,发现２个令人感兴趣的克隆,一个对应于黄孢原毛平革菌过氧化物酶基因lpoB的部分片段,另一个为编码一种热激蛋白的基因.     

Roles of phospholipase D in phorbol myristate acetate‐stimulated neutrophil respiratory burst

The phorbol myristate acetate (PMA) stimulated nutrophil respiratory burst has been considered to simply involve the activation of protein kinase C (PKC). However, the PLD activity was also increased by 10‐fold in human neutrophils stimulated with 100 nM PMA. Unexpectedly, U73122, an inhibitor of phospholipase C, was found to significantly inhibit PMA‐stimulated respiratory burst in human neutrophils. U73122 at the concentrations, which were sufficient to inhibit the respiratory burst completely, caused partial inhibition of the PLD activity but no inhibition on PKC translocation and activation, suggesting that PLD activity is also required in PMA‐stimulated respiratory burst. Using 1‐butanol, a PLD substrate, to block phosphatidic acid (PA) generation, the PMA‐stimulated neutrophil respiratory burst was also partially inhibited, further indicating that PLD activation, possibly its hydrolytic product PA and diacylglycerol (DAG), is involved in PMA‐stimulated respiratory burst. Since GF109203X, an inhibitor of PKC that could completely inhibit the respiratory burst in PMA‐stimulated neutrophils, also caused certain suppression of PLD activation, it may suggest that PLD activation in PMA‐stimulated neutrophils might be, to some extent, PKC dependent. To further study whether PLD contributes to the PMA stimulated respiratory burst through itself or its hydrolytic product, 1,2‐dioctanoyl‐sn‐glycerol, an analogue of DAG , was used to prime cells at low concentration, and it reversed the inhibition of PMA‐stimulated respiratory burst by U73122. The results indicate that U73122 may act as an inhibitor of PLD, and PLD activation is required in PMA‐stimulated respiratory burst.     

DIVERGE: phylogeny-based analysis for functional-structural divergence of a protein family

SUMMARY: DetectIng Variability in Evolutionary Rates among GEnes (DIVERGE) is a software system to study functional divergence of a protein family by detecting site-specific change in evolutionary rate using a multiple alignment of amino acid sequences for a given phylogenetic tree. The program first conducts a statistical test for site-specific rate shifts along the tree, and predicting candidate amino acid residues responsible for functional divergence based on posterior analysis. These results can then be mapped on the 3D protein structure if available. AVAILABILITY: DIVERGE is available free of charge from http://xgu1.zool.iastate.edu/. Distribution packages for both Linux and Microsoft Windows operating systems are available, including manual and example files.     

Selenium addition alters mercury uptake,bioavailability in the rhizosphere and root anatomy of rice (Oryza sativa)

Background and Aims

Mercury (Hg) is an extremely toxic pollutant, especially in the form of methylmercury (MeHg), whereas selenium (Se) is an essential trace element in the human diet. This study aimed to ascertain whether addition of Se can produce rice with enriched Se and lowered Hg content when growing in Hg-contaminated paddy fields and, if so, to determine the possible mechanisms behind these effects.

Methods

Two cultivars of rice (Oryza sativa, japonica and indica) were grown in either hydroponic solutions or soil rhizobags with different Se and Hg treatments. Concentrations of total Hg, MeHg and Se were determined in the roots, shoots and brown rice, together with Hg uptake kinetics and Hg bioavailability in the soil. Root anatonmy was also studied.

Key Results

The high Se treatment (5 μg g^–1) significantly increased brown rice yield by 48 % and total Se content by 2·8-fold, and decreased total Hg and MeHg by 47 and 55 %, respectively, compared with the control treatments. The high Se treatment also markedly reduced ‘water-soluble’ Hg and MeHg concentrations in the rhizosphere soil, decreased the uptake capacity of Hg by roots and enhanced the development of apoplastic barriers in the root endodermis.

Conclusions

Addition of Se to Hg-contaminated soil can help produce brown rice that is simultaneously enriched in Se and contains less total Hg and MeHg. The lowered accumulation of total Hg and MeHg appears to be the result of reduced bioavailability of Hg and production of MeHg in the rhizosphere, suppression of uptake of Hg into the root cells and an enhancement of the development of apoplastic barriers in the endodermis of the roots.     

M16添加牛磺酸和EDTA支持昆明白小鼠体外受精并发育至囊胚

在以往研究工作的基础上证明了通过添加2.5mmol/L的牛磺酸和0.1mmol/L的EDTA至M16培养液中,可支持昆明白小鼠的体外受精（IVF）,并支持受精卵突破2－细胞阻滞发育至囊胚期。本研究进一步证明了牛磺酸和EDTA在昆明小鼠早期胚胎发育和克服2－细胞阻滞中起关键作用。 Abstract:The results of our early experiments show that the 2-cell block can be overcome by culturing zygote in modified M16 ,modified CZB and TE medium.Our research shows that the taurine and EDTA play key role in overcoming 2-cell block in Kunming mouse.The results show that the addition of taurine and EDTA to M16 medium can support the IVF and develoment to blastocyst in vitro in Kunming strain mice.This is the first report that M16 medium added with taurine and EDTA can be used in both IVF and culture medium to overcome the 2-cell block of embryo development in Kunming strain mouse.     

新版DELTA系统在植物分类学中的应用——以羊茅属研究为例

DELTA系统是针对分类学研究开发的综合性多功能软件包。新版DELTA系统在运行环境、程序、指令、界面、操作方式及中文字符处理等重要功能上比旧版本均有较大改进。作为国际分类学数据库数据交换标准,应用该系统可以规范分类学描述,对研究中所有常用性状进行识别和处理,自动生成各个研究对象分类学特征描述并对其进行详尽的相似性和差异性比较,对性状特征和分类单元进行注释和图像示例,将数据转换为数量分类学或分支分类学所需格式以生成树状图,自动生成检索表,建成基于本地和网络的交互式专家辅助鉴定系统等。DELTA系统作为植物分类学研究的常用手段和工具是非常适合及大有帮助的。     

Cytoplasmic domain and enzymatic activity of ACE2 are not required for PI4KB dependent endocytosis entry of SARS-CoV-2 into host cells

The recent COVID-19 pandemic poses a global health emergency. Cellular entry of the causative agent SARS-CoV-2 is mediated by its spike protein interacting with cellular receptor-human angiotensin converting enzyme 2 (ACE2). Here, by using lentivirus based pseudotypes bearing spike protein, we demonstrated that entry of SARS-CoV-2 into host cells was dependent on clathrin-mediated endocytosis, and phosphoinositides played essential roles during this process. In addition, we showed that the intracellular domain and the catalytic activity of ACE2 were not required for efficient virus entry. Finally, we showed that the current predominant Delta variant, although with high infectivity and high syncytium formation, also entered cells through clathrin-mediated endocytosis. These results provide new insights into SARS-CoV-2 cellular entry and present proof of principle that targeting viral entry could be an effective way to treat different variant infections.