Diverse set of microRNAs are responsive to powdery mildew infection and heat stress in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Background  

MicroRNAs (miRNAs) are a class of small non-coding regulatory RNAs that regulate gene expression by guiding target mRNA cleavage or translational inhibition. MiRNAs can have large-scale regulatory effects on development and stress response in plants.     

Prevalence of genetic differences in phosphorylcholine expression between nontypeable <Emphasis Type="Italic">Haemophilus influenzae</Emphasis> and <Emphasis Type="Italic">Haemophilus haemolyticus</Emphasis>

Background  

Although non-typeable (NT) Haemophilus influenzae and Haemophilus haemolyticus are closely related human commensals, H. haemolyticus is non-pathogenic while NT H. influenzae is an important cause of respiratory tract infections. Phase-variable phosphorylcholine (ChoP) modification of lipooligosaccharide (LOS) is a NT H. influenzae virulence factor that, paradoxically, may also promote complement activation by binding C-reactive protein (CRP). CRP is known to bind more to ChoP positioned distally than proximally in LOS, and the position of ChoP within LOS is dictated by specific licD alleles (designated here as licD _I , licD _III , and licD _IV ) that are present in a lic1 locus. The lic1 locus contains the licA-licD genes, and ChoP-host interactions may also be influenced by a second lic1 locus that allows for dual ChoP substitutions in the same strain, or by the number of licA gene tetranucleotide repeats (5'-CAAT-3') that reflect phase-variation mutation rates.     

用于丙型肝炎病毒抗原测定的SiO_2载体的制备及其性质分析

为了优化将抗体偶联在二氧化硅试管表面上以便进行丙型肝炎抗原检测的分析系统,本研究通过氨基硅烷的活化作用,在玻璃表面形成活化的氨基,以戊二醛作为化学交联试剂,在已硅化的玻璃表面固定丙肝单克隆抗体,并进行丙肝抗原(HCAg)的测定。结果显示,通过条件优化实验,发现以10%(V/V)的氨基硅烷水溶液处理玻璃试管3h后,再用3%(V/V)的戊二醛水溶液交联丙肝单克隆抗体2h,可以得到固定效果较好,非特异性较低的玻璃载体,对HCAg可测至1μg/L。可见,用该方法制备的玻璃载体可为进一步建立新的HCAg磁性免疫检测系统提供理论和实验依据。     

大肠杆菌丝氨酸羟甲基转移酶基因(glyA)的克隆和表达

利用插入失活及营养缺陷型互补法将大肠杆菌K12 13kb的glyA基因克隆到质粒pBR329中。将重组质粒酶切,亚克隆,确定2.6kb PstI-EcoRI亚克隆片段带有完整的glyA基因。共获得12株glyA基因重组菌,对重组质粒进行了酶切鉴定。不同重组菌丝氨酸羟甲基转移酶(SHMT)活性及其酶表达量均不相同。受体菌未检测到丝氨酸的产生。重组菌株JM109(pSM13)、K12(pSM13)、K12(pSM14)和K12(pSM15)SHMT酶表达量分别占全菌可溶性蛋白的15.7％、15.4％、11.8％和9.48％。     

The Combined Deletion of S6K1 and Akt2 Deteriorates Glycemic Control in a High-Fat Diet

Signaling downstream of mechanistic target of rapamycin complexes 1 and 2 (mTORC1 and mTORC2) controls specific and distinct aspects of insulin action and nutrient homeostasis in an interconnected and as yet unclear way. Mice lacking the mTORC1 substrate S6 kinase 1 (S6K1) maintain proper glycemic control with a high-fat diet. This phenotype is accompanied by insulin hypersensitivity, Akt- and AMP-activated kinase upregulation, and increased lipolysis in adipose tissue and skeletal muscle. Here, we show that, when S6K1 inactivation is combined with the deletion of the mTORC2 substrate Akt2, glucose homeostasis is compromised due to defects in both insulin action and β-cell function. After a high-fat diet, the S6K1(-/-) Akt2(-/-) double-mutant mice do not become obese, though they are severely hyperglycemic. Our data demonstrate that S6K1 is required for pancreatic β-cell growth and function during adaptation to insulin resistance states. Strikingly, the inactivation of two targets of mTOR and phosphatidylinositol 3-kinase signaling is sufficient to reproduce major hallmarks of type 2 diabetes.     

Genomic insights into selection for heterozygous alleles and woody traits in Populus tomentosa

Heterozygous alleles are widespread in outcrossing and clonally propagated woody plants. The variation in heterozygosity that underlies population adaptive evolution and phenotypic variation, however, remains largely unknown. Here, we describe a de novo chromosome-level genome assembly of Populus tomentosa, an economic and ecologically important native tree in northern China. By resequencing 302 natural accessions, we determined that the South subpopulation (Pop_S) encompasses the ancestral strains of P. tomentosa, while the Northwest subpopulation (Pop_NW) and Northeast subpopulation (Pop_NE) experienced different selection pressures during population evolution, resulting in significant population differentiation and a decrease in the extent of heterozygosity. Analysis of heterozygous selective sweep regions (HSSR) suggested that selection for lower heterozygosity contributed to the local adaptation of P. tomentosa by dwindling gene expression and genetic load in the Pop_NW and Pop_NE subpopulations. Genome-wide association studies (GWAS) revealed that 88 single nucleotide polymorphisms (SNPs) within 63 genes are associated with nine wood composition traits. Among them, the selection for the homozygous AA allele in PtoARF8 is associated with reductions in cellulose and hemicellulose contents by attenuating PtoARF8 expression, and the increase in lignin content is attributable to the selection for decreases in exon heterozygosity in PtoLOX3 during adaptive evolution of natural populations. This study provides novel insights into allelic variations in heterozygosity associated with adaptive evolution of P. tomentosa in response to the local environment and identifies a series of key genes for wood component traits, thereby facilitating genomic-based breeding of important traits in perennial woody plants.     

格氏栲天然林林窗植物物种多样性与系统发育多样性

林窗环境异质性导致群落物种多样性与系统发育多样性(phylogenetic diversity, PD)存在差异, 研究不同大小的林窗中群落的物种多样性与系统发育多样性有助于揭示林下生物多样性的形成及维持机制。本文以格氏栲(Castanopsis kawakamii)天然林为研究对象, 通过Pearson相关性分析与广义线性模型探讨了林窗内物种多样性与系统发育多样性间的相互关系及其环境影响因素。结果表明: (1)大林窗(面积 > 200 m²)植物种类及多度均高于中林窗(50 m² ≤ 面积 < 100 m²)、小林窗(30 m² ≤ 面积 < 50 m²)和非林窗(面积 = 100 m²)。大林窗群落系统发育结构趋于发散, 中、小林窗和非林窗群落系统发育结构受到生境过滤和竞争排斥综合作用。(2)群落系统发育多样性指数与物种丰富度(species richness, SR)、Margalef丰富度指数和Shannon-Wiener指数均呈显著正相关, 这与林窗内稀有种种类组成多于优势种有关。(3)林窗面积对物种多样性存在显著正效应; 土壤全氮含量对系统发育多样性和系统发育结构存在显著正效应。林窗形成提高了格氏栲天然林群落物种多样性和系统发育多样性, 林窗面积与土壤全氮共同驱动了格氏栲天然林林窗物种多样性和系统发育多样性的变化。     

Identification and characterization of yak (Bos grunniens) b-Boule gene and its alternative splice variants

Boule is responsible for meiotic arrest of sperms and male sterility during mammalian spermatogenesis. In the present study, we first identified yak b-Boule gene and its two alternative splice variants. The full length coding region of yak b-Boule is 888 bp and encodes a 295-amino acid protein with a typical RNA-recognition motif (RRM) and a Deleted in Azoospermia (DAZ) repetitive sequence motif. Two alternative splice variants of yak b-Boule were generated following the consensus “GT-AG” rule and named b-Boule1 (36 bp deletion in exon 3) and b-Boule2 (deletion of integral exon 7), respectively. In male yak, b-Boule, b-Boule1 and b-Boule2 were found to be exclusively expressed in the testes at a ratio of 81:0.1:1. Intriguingly, the mRNA expression levels of b-Boule and b-Boule1 in yak testis were significantly higher than those in cattle–yak, although no significant difference was observed for b-Boule2 expression between the yak and cattle–yak. These results suggest that b-Boule gene, which is partially regulated by alternative splicing, may be involved in the process of yak spermatogenesis.     

癔症发作诱发因素以及复发几率分析

目的:探讨导致癔症发病病因和复发几率之间的联系,以便为研究、预防和治疗癔症工作提供科学依据。方法:以近30年国内外有关癔症危险因素的研究成果为基础,对符合CCMD-3诊断标准的100例癔症患者进行回顾性分析及前瞻性观察。结果:癔症相关的危险因素比较多,患者多内向,神经质影响心理症状最大,情绪明显不稳定;他们的父母较正常人的父母对子女缺乏情感温暖,并有过度的拒绝和过度保护,家庭不和睦,其在发病前一年内负性生活事件数目与严重程度均高于一般人;情绪表达受限,生活单调乏味,父母采取不良教养方式,人际关系紧张等。且患者性格因素引起的癔症复发几率较高,而因负性生活事件的原因复发几率在几种情况中最低。结论:癔症病因主要有人格特征,家庭环境,生活事件,教养方式,人际关系等,正确教育方式和朋友良好的关系,以及和谐的家庭及社会环境,及时治疗相关的并发症,可明显减少发病和复发概率。