Phylogeographic breaks and the mechanisms of their formation in the Sino-Japanese floristic region

Due to combinations of diverse geography and climate, and complex geo-climate histories and sea level fluctuations, the Sino-Japanese floristic region has extremely high species diversity. Phylogeography is an effective method to identify the factors triggering the formation and differentiation of species diversity. Previous studies showed that phylogeographic breaks, the genetic discontinuity between different gene genealogies, were ubiquitously present. From the west to the east, seven general phylogeographic breaks occur, including the Mekong- Salween Divide, the Tanaka-Kaiyong Line, the Sichuan Basin, ca. 105° E, the boundary between the Second and Third ladders, the North China, and the East China Sea and Korea Strait. These phylogeographic breaks are mainly attributable to both historical and ecological factors, which are generally due to a combined effect of the isolation by distance (IBD) and the isolation by environment (IBE). Geological events and climate changes are the historical factors, mainly including the uplift of Qinghai-Xizang Plateau, the formation and intensification of the Asian monsoon and the Asian interior aridification, the redevelopment of the arid belt, and the Quaternary climate oscillations and sea level fluctuations. Adaptive divergence, namely the divergence induced by different selective pressures under different environments, is responsible for the ecological factors. Adaptive divergence could obstacle gene flow among populations, resulting in the formation of phylogeographic break. However, an identical phylogeographic break is not shared by all the plants because of their various intrinsic biological characteristics, among which the difference in dispersal ability is most important. Finally, we envisaged the future development of phylogeographic break studies based on accurate divergence time estimation, relative contribution of IBD and IBE, and also the utilization of comparative phylogeography.     

Study of Saharan dust influence on PM10 measures in Sicily from 2013 to 2015

Nowadays, particulate matter, especially that with small dimension as PM₁₀, PM_2.5 and PM_1, is the air quality indicator most commonly associated with a number of adverse health effects. In this paper it is analyzed the impact that a natural event, such as the transport of Saharan dust, can have on increasing the particulate matter concentration in Sicily.Consulting the data of daily PM₁₀ concentration, acquired by air quality monitoring network belonging to “Agenzia Regionale Protezionedell’ Ambiente” (Environmental Protection Regional Agency), it was possible to analyze the trend from 2013 to 2015. The days, in which the limit value was exceeded, were subjected to combined analysis. It was based on three models: interpretations of the air masses back-trajectories, using the atmospheric model HYSPLIT (HYbrid Single-Particle Lagrangian Integrated trajectory); on the calculation of the concentration on the ground and at high altitude particulate applying DREAM model (Dust REgional atmospheric model) and on the calculation of the concentration of mineral aerosols according to the atmospheric optical thickness (AOT) applying NAAPS model (Navy Aerosol Analysis and Prediction System).The daily limit value exceedances were attributed to the transport of Saharan dust events exclusively when the three models were in agreement with each other. Identifying the natural events, it was possible to quantify the contribution of the Saharan dust and consequently the reduction of the exceedances number. To quantify the contribution of Saharan dust on daily PM₁₀ concentration, it was calculated the regional background in according to precautionary approach recommended by “Guidance on the quantification of the contribution of natural sources under the EU Air Quality Directive 2008/50/EC”, when the application of the method cannot be validated with chemical analysis, as in this case. In this study is obtained, as the most important quantitative goal, the convergence of the three models to the same result. So, is evident that exceedances of the daily limit value that occurred from 2013 to 2015 in Sicily can be attributed, in most cases, to the Saharan dust intrusion.     

Genotyping of white spot syndrome virus in Chinese cultured shrimp during 1998–1999

Recent studies showed that white spot syndrome virus (WSSV) isolates from different geographic locations share a high genetic similarity except the variable regions in ORF23/24 and ORF14/15, and variable number of tandem repeats (VNTR) within ORF94. In this study, genotyping was performed according to these three variable regions among WSSV isolates collected during 1998/1999 from Southern China. These WSSV isolates contain a deletion of 1168, 5657, 5898, 9316 and 11093 bp, respectively in the variable region ORF23/24 compared with WSSV-TW, and a deletion of 4749 or 5622 bp in the variable region ORF14/15 relative to TH-96-II. Four types of repeat units (RUs) (6, 8, 9 and 13 RUs) in ORF94 were detected in these isolates, with the shortest 6 RUs as the most prevalent type. Our results provide important information for a better understanding of the spatio-temporal transmission mode and the WSSV genetic evolution lineage.     

黑线姬鼠两亚种(中国东北地区及俄罗斯远东地区的东北亚种和朝鲜半岛的朝鲜亚种) 的线粒体DNA 序列缺少趋异性

为了检测黑线姬鼠两亚种(来自中国东北地区、俄罗斯远东地区的东北亚种和朝鲜半岛的朝鲜亚种)线
粒体DNA 的变异水平并确定朝鲜亚种的分类地位,我们测序分析了两亚种的线粒体DNA 细胞色素b 的部分序列
(1 054 bp)和控制区的部分序列(860 bp),并与基因库中黑线姬鼠相应的单倍型序列进行了比较。可以看出东
北亚种的序列显示出某些分异,可以被分为2 或3 个亚群,所以我们提出需要更多标本的DNA 分析来确定东北
亚种的分类地位。另外,来自韩国的朝鲜亚种的序列,与来自中国东北地区龙江和哈尔滨的东北亚种的两个亚
群相似(1 个亚群是细胞色素b 的两个单倍型,另1 个是控制区的两个单倍型),表明基于线粒体DNA 序列的遗
传多样性与现今基于形态特征对这些姬鼠的分类所得结果是不一致的。因此我们认为来自韩国的朝鲜亚种是一
个只在形态特异上不同于东北亚种的地方亚种,我们建议通过其他DNA 标记来进一步验证其亚种地位。我们还
认为朝鲜半岛不是最近的冰川期黑线姬鼠残遗种的保护区。     

浙江武义2009年南方水稻黑条矮缩病的毒源地分析

2009年, 浙江省境内首次出现南方水稻黑条矮缩病毒(Southern rice black streaked dwarf virus, SRBSDV), 且仅武义县有发病现象。因为该病毒病是一种虫媒病毒, 且白背飞虱Sogatella furcifera (Horváth)是主要传毒介体, 所以本文通过白背飞虱灯下诱虫情况调查、 迁飞轨迹模拟、 天气学背景分析以及毒源地分析, 阐释了2009年浙江省武义县发现的南方水稻黑条矮缩病的供毒源地分布情况, 以及白背飞虱携毒的传递路径, 并讨论了轨迹模拟中各生物学参数的设定方法, 从而为剖析该病毒的宏观流行规律奠定科学基础。结果显示：(1) 通过对白背飞虱迁入武义的主要虫源地与经鉴定的南方水稻黑条矮缩病发病区域的叠加分析, 明确了浙江武义的可能毒源地分布于两广、 闽南、 赣南四省区境内; (2) 西南低空急流及偏南气流是白背飞虱将我国南方的病毒远距离传送到武义县境内的动力源; (3) 白背飞虱随下沉气流和降雨在武义境内的集中降落是南方水稻黑条矮缩病在当地暴发的触发条件。     

喀斯特峰丛洼地不同类型森林群落的组成与生物多样性特征

不同退化程度石漠化生态重建的关键是恢复植被, 提高土地生产力。本文基于动态监测样地(200 m × 40 m)植被的全面调查, 研究了喀斯特峰丛洼地人工林、次生林和原生林3类典型森林群落木本植物的组成与生物多样性特征。结果表明, 3类森林的物种组成分别为26科52属65种、33科68属100种和43科91属123种, 常绿物种分别占41.54%、47.00%和52.85%; 科、属、种和生活型组成复杂, 优势科或种明显, TWINSPAN分类第3级水平上可分别划分为8、9和8个群落类型。原生林多样性和结构性指标均高于人工林和次生林, 人工林的Shannon-Wiener指数、Simpson指数、均匀度、冠幅、胸径和树高均高于次生林, 而种类、密度和盖度则低于次生林。不同类型森林群落特征不同, 应采取相应的经营策略。     

土层浅薄地区植物水分来源研究方法

植物水分来源取决于环境中有效水的分布及植物获取水分的能力.旱季,土层浅薄地区土壤水无法满足植物生长的需要,植物能否利用风化基岩层水分是其能否维持正常水分消耗的关键.本文综述了4种土层浅薄地区植物水分来源的研究方法,包括调查和分析植物根系生长与分布特征、监测地表以下各层次水分变化、监测并分析植物体水分指标季节变化以及运用稳定同位素技术区分植物水分来源,并进一步分析了各种方法的优势和局限性及其在我国西南喀斯特地区植物水分来源研究中的应用前景.     

A Simplified Mass-Transfer Model for Visual Pigments in Amphibian Retinal-Cone Outer Segments

When radiolabeled precursors and autoradiography are used to investigate turnover of protein components in photoreceptive cone outer segments (COSs), the labeled components—primarily visual pigment molecules (opsins)—are diffusely distributed along the COS. To further assess this COS labeling pattern, we derive a simplified mass-transfer model for quantifying the contributions of advective and diffusive mechanisms to the distribution of opsins within COSs of the frog retina. Two opsin-containing regions of the COS are evaluated: the core axial array of disks and the plasmalemma. Numerical solutions of the mass-transfer model indicate three distinct stages of system evolution. In the first stage, plasmalemma diffusion is dominant. In the second stage, the plasmalemma density reaches a metastable state and transfer between the plasmalemma and disk region occurs, which is followed by an increase in density that is qualitatively similar for both regions. The final stage consists of both regions slowly evolving to the steady-state solution. Our results indicate that autoradiographic and cognate approaches for tracking labeled opsins in the COS cannot be effective methodologies for assessing new disk formation at the base of the COS.     

MicroRNA-124 suppresses oral squamous cell carcinoma motility by targeting ITGB1

Alterations in the levels of molecules which interact with the extracellular matrix, such as integrins, are associated with invasion of oral squamous cell carcinomas (OSCC). The molecular mechanisms underlying dysregulation of integrin expression in OSCC, however, remain unclear. Here, we show that microRNA-124, a small non-coding RNA down-regulated in OSCC, is able to downregulate expression of integrin beta-1 (ITGB1) by interacting with its 3′ untranslated region. Over-expression of miR-124 attenuates endogenous ITGB1 expression and reduces the adherence and motility of OSCC cells, suggesting disruption of miR-124-mediated repression of ITGB1 may be a key factor in OSCC progression.