苜蓿叶象啮小蜂寿命及产卵量的研究

在室内通过对苜蓿叶象啮小蜂Tetrastichus incertus（Ratzeburg）寿命、产卵量的研究发现,苜蓿叶象啮小蜂有较高的产卵量和寄生能力;在不喂食的条件下,苜蓿叶象啮小蜂产卵量最高,单头雌蜂的产卵范围为45粒-209粒,平均117粒,最高日产卵量为31粒;其寿命可达18d,最多可寄生37头寄主;苜蓿叶象啮小蜂与寄主在1：5的情况下寄生率达56.00%,并随着寄主密度的增大,苜蓿叶象啮小蜂的产卵量也有逐渐升高的趋势。     

The kinase activity of IL-1 receptor-associated kinase 4 is required for interleukin-1 receptor/toll-like receptor-induced TAK1-dependent NFkappaB activation

Two parallel interleukin-1 (IL-1)-mediated signaling pathways have been uncovered for IL-1R-TLR-mediated NFkappaB activation: TAK1-dependent and MEKK3-dependent pathways, respectively. The TAK1-dependent pathway leads to IKKalpha/beta phosphorylation and IKKbeta activation, resulting in classic NFkappaB activation through IkappaBalpha phosphorylation and degradation. The TAK1-independent MEKK3-dependent pathway involves IKKgamma phosphorylation and IKKalpha activation, resulting in NFkappaB activation through dissociation of phosphorylated IkappaBalpha from NFkappaB without IkappaBalpha degradation. IL-1 receptor-associated kinase 4 (IRAK4) belongs to the IRAK family of proteins and plays a critical role in IL-1R/TLR-mediated signaling. IRAK4 kinase-inactive mutant failed to mediate the IL-1R-TLR-induced TAK1-dependent NFkappaB activation pathway, but mediated IL-1-induced TAK1-independent NFkappaB activation and retained the ability to activate substantial gene expression, indicating a structural role of IRAK4 in mediating this alternative NFkappaB activation pathway. Deletion analysis of IRAK4 indicates the essential structural role of the IRAK4 death domain in receptor proximal signaling for mediating IL-1R-TLR-induced NFkappaB activation.     

Stability of molecular adhesion mediated by confined polymer repellers and ligand-receptor bonds

Experiments have shown that stable adhesion of a variety of animal cells on substrates prepared with precisely controlled ligand distribution can be formed only if the ligand spacing is below 58 nm. To explain this phenomenon, here we propose a confined polymer model to study the stability of molecular adhesion mediated by polymer repellers and ligand-receptor bonds. In this model, both repellers and binders are treated as wormlike chains confined in a nanoslit, and the stability of adhesion is considered as a competition between attractive interactions of ligand-receptor binding and repulsive forces due to the size mismatch between repellers and binders. The force on each ligand-receptor bond is calculated from the confined polymer model, and the classic model of Bell is used to describe the association/dissociation reactions of ligand-receptor bonds. The calculated equilibrium bond distribution shows that there exists a critical ligand density for stable adhesion, corresponding to a critical ligand spacing which agrees not only qualitatively but also quantitatively with the experimental observation. In the case of stable adhesion, the model predicts an equilibrium separation between adhesion surfaces below 60% of the contour length of the ligand-receptor bonds.     

Structure of the alamethicin pore reconstructed by x-ray diffraction analysis

We reconstructed the electron density profile of the alamethicin-induced transmembrane pore by x-ray diffraction. We prepared fully hydrated multiple bilayers of alamethicin-lipid mixtures in a condition where pores were present, as established previously by neutron in-plane scattering in correlation with oriented circular dichroism. At dehydrated conditions, the interbilayer distance shortened and the interactions between bilayers caused the membrane pores to become long-ranged correlated and form a periodically ordered lattice of rhombohedral symmetry. To resolve the phase problem of diffraction, we used a brominated lipid and performed multiwavelength anomalous diffraction at the bromine K edge. The result unambiguously shows that the alamethicin pore is of the barrel-stave type consisting of eight alamethicin helices. This pore structure corresponds to the stable pores detected by neutron in-plane scattering in fully hydrated fluid bilayers at high peptide/lipid ratios, which are the conditions at which alamethicin was tested for its antibacterial activity.     

一例智力低下患者7q~ 标记染色体的来源鉴定

以人类染色体显微切割、PCR技术构建的现有人类染色体特异性和染色体区带特异性探针池作为绘画探针,采用正向染色体绘画技术,结合染色体筛查方法,查明了一例7q~ 标记染色体患者的染色体附加片段来源于3q26→3qter。确定该患者的核型为46,XX,-7, der(7)t(7;3)(7pter→7q32::3q26→3qter)。应用这个策略,能够快速有效地鉴定标记染色体的来源。     

生态-经济发展情景下内蒙古宏观生态系统模拟与分析

内蒙古自治区是我国北方面积最大、种类最全的生态功能区,是我国北方的重要生态屏障,其宏观生态系统状况不仅关系民众生存和生计,而且关系华北、东北、西北乃至全国的生态安全。构建了1990、2000及2015年3期宏观生态系统格局与影响因子数据集;融合区域生态系统发展规划,设置了基准、生态-经济协同发展和生态-经济权衡发展三种情景;应用土地利用均衡分析模型,模拟了3种情景下2025年及2035年内蒙古六大类生态系统结构与空间格局变化。结果表明：在延续历史发展趋势的基准情景和注重经济发展的生态-经济权衡发展情景下,草地和农田生态系统在2035年均无法恢复至2000年的水平,宏观生态系统结构难以达到规划目标;在注重生态保育的生态-经济协同发展情景下,草地、森林与湿地生态系统面积增长较大,符合内蒙古构建中国北方生态屏障的战略定位。从空间上看,农田生态系统面积的减少主要集中在农牧交错带地区,该区域的退耕还草构成了草地生态系统增加的主要来源;草地生态系统面积扩张还分布在近十年来发生草地退化的区域,这与近年来通过实施"京津风沙源治理"、"草原奖补政策"等生态工程建设后内蒙古自治区原有退化的草地生态系统在逐渐恢复的趋势相吻合;森林生态系统面积增加主要集中分布在大兴安岭等几个植被恢复地;城市生态系统主要以原有城镇居民点为中心,在其周边区域呈扩散式增长,特别是在采矿场、工业用地、交通沿线附近城镇面积增加较为显著;荒漠生态系统的缩减主要发生在与其它生态系统的交界处,这与开发利用的便利性、原有生态系统的可开发潜力等密切相关。研究表明,生态-经济发展情景下的宏观生态系统的空间显性模拟是区域国土空间规划和可持续发展的重要科学依据。     

Genome-wide CRISPR activation screen identifies candidate receptors for SARS-CoV-2 entry

Science China Life Sciences - The outbreak of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has created a global health crisis. SARS-CoV-2 infects varieties of tissues where the known...     

The complete mitochondrial genome of Taeniogonalos taihorina (Bischoff) (Hymenoptera: Trigonalyidae) reveals a novel gene rearrangement pattern in the Hymenoptera

The family Trigonalyidae is considered to be one of the most basal lineages in the suborder Apocrita of Hymenoptera. Here, we determine the first complete mitochondrial genome of the Trigonalyidae, from the species Taeniogonalos taihorina (Bischoff, 1914). This mitochondrial genome is 15,927 bp long, with a high A + T-content of 84.60%. It contains all of the 37 typical animal mitochondrial genes and an A + T-rich region. The orders and directions of all genes are different from those of previously reported hymenopteran mitochondrial genomes. Eight tRNA genes, three protein-coding genes and the A + T-rich region were rearranged, with the dominant gene rearrangement events being translocation and local inversion. The arrangements of three tRNA clusters, trnY–trnM–trnI–trnQ, trnW–trnL2–trnC, and trnH–trnA–trnR–trnN–trnS–trnE–trnF, and the position of the cox1 gene, are novel to the Hymenoptera, even the insects. Six long intergenic spacers are present in the genome. The secondary structures of the RNA genes are normal, except for trnS2, in which the D-stem pairing is absent.     

抗烯醇化酶抗体与（1-3）-β-D-葡聚糖检测诊断侵袭性念珠菌病的临床比较

目的：比较抗烯醇化酶抗体（抗-Eno）检测与（1-3）-β-D-葡聚糖（BG）检测对侵袭性念珠菌病（invasivecandidia-sis,IC）的诊断价值。方法留取临床为诊断IC而送检BG测定的患者血样,用ELISA法测定抗-Eno抗体,以真菌培养结果为基础,分析比较两种血清学方法诊断IC的效能。结果210例患者为研究对象。15例患者经念珠菌培养确诊IC,确诊感染率71%;BG阳性54例,阳性率为257%;抗-Eno阳性33例,检出阳性率为157%。抗-Eno和G试验诊断IC感染的敏感性、特异性、阳性预测值、阴性预测值分别为467%、867%、212%、955%和333%、749%、93%、936%。两种血清学方法联合检测,敏感性提高至667%。结论抗-Eno对IC的诊断性能优于G试验;联合两种血清学方法,能有效提高敏感性。     

A Conserved Isoleucine Maintains the Inactive State of Bruton's Tyrosine Kinase

Despite high level of homology among non-receptor tyrosine kinases, different kinase families employ a diverse array of regulatory mechanisms. For example, the catalytic kinase domains of the Tec family kinases are inactive without assembly of the adjacent regulatory domains, whereas the Src kinase domains are autoinhibited by the assembly of similar adjacent regulatory domains. Using molecular dynamics simulations, biochemical assays, and biophysical approaches, we have uncovered an isoleucine residue in the kinase domain of the Tec family member Btk that, when mutated to the closely related leucine, leads to a shift in the conformational equilibrium of the kinase domain toward the active state. The single amino acid mutation results in measureable catalytic activity for the Btk kinase domain in the absence of the regulatory domains. We suggest that this isoleucine side chain in the Tec family kinases acts as a “wedge” that restricts the conformational space available to key regions in the kinase domain, preventing activation until the kinase domain associates with its regulatory subunits and overcomes the energetic barrier to activation imposed by the isoleucine side chain.