Neuraminidase and Hemagglutinin Matching Patterns of a Highly Pathogenic Avian and Two Pandemic H1N1 Influenza A Viruses

Background

Influenza A virus displays strong reassortment characteristics, which enable it to achieve adaptation in human infection. Surveying the reassortment and virulence of novel viruses is important in the prevention and control of an influenza pandemic. Meanwhile, studying the mechanism of reassortment may accelerate the development of anti-influenza strategies.

Methodology/Principal Findings

The hemagglutinin (HA) and neuraminidase (NA) matching patterns of two pandemic H1N1 viruses (the 1918 and current 2009 strains) and a highly pathogenic avian influenza A virus (H5N1) were studied using a pseudotyped particle (pp) system. Our data showed that four of the six chimeric HA/NA combinations could produce infectious pps, and that some of the chimeric pps had greater infectivity than did their ancestors, raising the possibility of reassortment among these viruses. The NA of H5N1 (A/Anhui/1/2005) could hardly reassort with the HAs of the two H1N1 viruses. Many biological characteristics of HA and NA, including infectivity, hemagglutinating ability, and NA activity, are dependent on their matching pattern.

Conclusions/Significance

Our data suggest the existence of an interaction between HA and NA, and the HA NA matching pattern is critical for valid viral reassortment.     

植物赤霉素矮化突变体研究进展

赤霉素(GAs)在植物种子萌发、茎的伸长和花的发育等方面起着非常重要的作用。近年来,随着研究手段和技术不断进步,对赤霉素(GA)生物合成和信号传导过程中相关基因的研究取得了惊人的进展。与GA有关的矮化突变体主要有GA缺陷型和不敏感型两类,本文对与GA生物合成和信号传导过程中有关的这两类矮突变体的研究进展进行综述。对这些这些突变体的研究促进了对赤霉素生物合成和信号传导途径的认识,同时为赤霉素更好地利用提供了科学依据。     

藤本月季“安吉拉”花芽分化形态结构及内源激素变化研究

以藤本月季“安吉拉”为试验材料,通过石蜡切片、体视显微镜观察及内源激素的测定,研究花芽分化过程的形态结构及内源激素的变化,为花期调控、景观品质的提升及相关育种工作提供基础数据。藤本月季“安吉拉”花芽各部分分化顺序由外向内进行,分为5个时期,共历时30 d,首先是生长锥呈圆锥状突起的形态分化期;扁平生长锥周围出现5个突起,即为萼片原基分化期;萼片原基的内方分化出成轮状的多个花瓣原基,即为花瓣原基分化期;花瓣原基基部从上向下分化出多轮雄蕊原基,即为雄蕊原基分化期;扁平的生长锥顶端突起形成多个雌蕊原基,为雌蕊原基分化期。随花芽分化进程脱落酸(ABA)、细胞分裂素(CTK)浓度变化规律相似,均呈先升高再下降趋势,萼片原基分化期其浓度均显著高于其他时期;生长素(IAA)浓度呈逐渐上升的趋势;赤霉素(GA)浓度呈逐渐下降趋势。随花芽分化进程IAA/GA和IAA/ABA比值呈逐渐上升趋势,CTK/GA和(ABA+CTK)/GA比值在萼片原基分化期显著高于形态分化期。内源激素测定结果表明:ABA、CTK浓度在萼片原基分化期显著升高与花芽分化诱导有关,较低的IAA浓度以及GA浓度的降低有利于藤本月季“安吉拉”的花芽分化;萼片原基分化期CTK/GA和(ABA+CTK)/GA比值升高可能与花芽分化诱导有关,高水平的IAA/ABA和IAA/GA比值可能与花器官原基的进一步发育相关。     

Topography of pleural epithelial structure enabled by en face isolation and machine learning

Pleural epithelial adaptations to mechanical stress are relevant to both normal lung function and parenchymal lung diseases. Assessing regional differences in mechanical stress, however, has been complicated by the nonlinear stress–strain properties of the lung and the large displacements with ventilation. Moreover, there is no reliable method of isolating pleural epithelium for structural studies. To define the topographic variation in pleural structure, we developed a method of en face harvest of murine pleural epithelium. Silver-stain was used to highlight cell borders and facilitate imaging with light microscopy. Machine learning and watershed segmentation were used to define the cell area and cell perimeter of the isolated pleural epithelial cells. In the deflated lung at residual volume, the pleural epithelial cells were significantly larger in the apex (624 ± 247 μm²) than in basilar regions of the lung (471 ± 119 μm²) (p < 0.001). The distortion of apical epithelial cells was consistent with a vertical gradient of pleural pressures. To assess epithelial changes with inflation, the pleura was studied at total lung capacity. The average epithelial cell area increased 57% and the average perimeter increased 27% between residual volume and total lung capacity. The increase in lung volume was less than half the percent change predicted by uniform or isotropic expansion of the lung. We conclude that the structured analysis of pleural epithelial cells complements studies of pulmonary microstructure and provides useful insights into the regional distribution of mechanical stresses in the lung.     

Early evolution of Cupedidae revealed by a mid‐Cretaceous reticulated beetle from Myanmar (Coleoptera: Archostemata)

Cupedidae, the most species‐rich family of the archaic suborder Archostemata, were abundant, diverse and widespread in the Mesozoic, yet little is known about the early evolution and biogeography. This stems, in part, from a lack of exceptionally preserved fossils from the Mesozoic and of formal phylogenetic study of both extant and extinct taxa. Here we describe and illustrate a new fossil from mid‐Cretaceous Burmese amber, and provide a phylogeny combining both fossils and all known extant genera of Archostemata. A dataset of 43 ingroup taxa and four outgroup taxa based on 110 morphological characters was analysed under parsimony. The results indicate that Priacma LeConte and Paracupes Kolbe, as well as the Cretaceous genera Barbaticupes Jarzembowski et al. and Mallecupes Jarzembowski et al., together form a sister clade to the rest of Cupedidae. Priacma megapuncta sp.n. is attributed to the relict North American Priacma by the presence of distinct subtruncate elytral apices, lateral elytral margins with two rows of sharp teeth, and peculiar fixing epipleural folds near the elytral apices. Our discovery of the first fossil species of Priacma in Burmese amber reveals the antiquity and wider distribution of the genus in the late Mesozoic. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:313565C2‐4F42‐48BD‐8720‐F379DE202868 .     

恒河猴胚胎浅表型植入机理的探讨

为揭示恒河猴胚胎浅表型植入的分子机理,实验采用免疫组化和原位杂交的方法研究了粘附侵润相关分子在妊娠恒河猴母胎界面的表达模式,发现层粘连蛋白(LN)、Ⅳ型胶原(ColⅣ)和基质金属蛋白酶-2(MMP-2)在滋养层细胞柱的远端开始表达;整合素α1β1从柱的近端到远端表达逐渐升高,但在滋养层细胞鞘中上述分子的表达均降低;大量侵润母体血管的滋养层细胞高水平表达上述分子。此外,植入早期上皮斑和蜕膜基质细胞高表达MMPs组织抑制因子-2(TIMP-2)。结果提示,滋养层细胞鞘中α1β1、LN、MMP-2表达水平的降低及上皮斑、蜕膜和滋养层细胞中TIMP-2的高表达可能是导致浅表型植入形成的分子基础。     

Urinary metabolite markers of precocious puberty

The incidence of precocious puberty (PP, the appearance of signs of pubertal development at an abnormally early age), is rapidly rising, concurrent with changes of diet, lifestyles, and social environment. The current diagnostic methods are based on a hormone (gonadotropin-releasing hormone) stimulation test, which is costly, time-consuming, and uncomfortable for patients. The lack of molecular biomarkers to support simple laboratory tests, such as a blood or urine test, has been a long standing bottleneck in the clinical diagnosis and evaluation of PP. Here we report a metabolomic study using an ultra performance liquid chromatography-quadrupole time of flight mass spectrometry and gas chromatography-time of flight mass spectrometry. Urine metabolites from 163 individuals were profiled, and the metabolic alterations were analyzed after treatment of central precocious puberty (CPP) with triptorelin depot. A panel of biomarkers selected from >70 differentially expressed urinary metabolites by receiver operating characteristic and logistic regression analysis provided excellent predictive power with high sensitivity and specificity for PP. The altered metabolic profile of the PP patients was characterized by three major perturbed metabolic pathways: catecholamine, serotonin metabolism, and tricarboxylic acid cycle, presumably resulting from activation of the sympathetic nervous system and the hypothalamic-pituitary-gonadal axis. Treatment with triptorelin depot was able to normalize these three altered pathways. Additionally, significant changes in the urine levels of 4-hydroxyphenylacetic acid, 5-hydroxyindoleacetic acid, indoleacetic acid, 5-hydroxytryptophan, and 5-hydroxykynurenamine in the CPP group suggest that the development of CPP condition may involve an alteration in symbiotic gut microbial composition.     

从非同源蛋白质的一级序列预测其结构类

对基于氨基酸组成、自相关函数和自协方差函数提取特征的蛋白质结构类预测算法进行分析比较,对氨基酸组成和自相关函数相结合的方法,以及氨基酸组成和自协放差函数相结合的方法的预测算法进行了研究。结果表明：对非同源蛋白质,因氨基酸和自相关函数相结合的方法中,采用Miyazawa和Jernigan的疏水值时,训练的自检验的总精度为95．34％,其Jackknife检验的总精度为81．92％,检验加的他检验的总精工为86．61％。在氨基酸组成和自协方差函数相结合的方法中,采用Wold等的疏水值时,训练库的自检验的总精度为96．71％,其Jackknife检验的总精度为82．18％,检验加的他检验的总精工为86．88％。这说明氨基酸组成和自相关函数相结合的方法,以及氨基酸组成和自协方差函数相结合的方法可有效提高结构类预测精度,表明提取更多有效的序列信息是提高分类精度的关键。     

Genetic variability,local selection and demographic history: genomic evidence of evolving towards allopatric speciation in Asian seabass

Genomewide analysis of genetic divergence is critically important in understanding the genetic processes of allopatric speciation. We sequenced RAD tags of 131 Asian seabass individuals of six populations from South‐East Asia and Australia/Papua New Guinea. Using 32 433 SNPs, we examined the genetic diversity and patterns of population differentiation across all the populations. We found significant evidence of genetic heterogeneity between South‐East Asian and Australian/Papua New Guinean populations. The Australian/Papua New Guinean populations showed a rather lower level of genetic diversity. F_ST and principal components analysis revealed striking divergence between South‐East Asian and Australian/Papua New Guinean populations. Interestingly, no evidence of contemporary gene flow was observed. The demographic history was further tested based on the folded joint site frequency spectrum. The scenario of ancient migration with historical population size changes was suggested to be the best fit model to explain the genetic divergence of Asian seabass between South‐East Asia and Australia/Papua New Guinea. This scenario also revealed that Australian/Papua New Guinean populations were founded by ancestors from South‐East Asia during mid‐Pleistocene and were completely isolated from the ancestral population after the last glacial retreat. We also detected footprints of local selection, which might be related to differential ecological adaptation. The ancient gene flow was examined and deemed likely insufficient to counteract the genetic differentiation caused by genetic drift. The observed genomic pattern of divergence conflicted with the ‘genomic islands’ scenario. Altogether, Asian seabass have likely been evolving towards allopatric speciation since the split from the ancestral population during mid‐Pleistocene.