The Genomic Basis of Color Pattern Polymorphism in the Harlequin Ladybird

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Increase in Male Reproductive Success and Female Reproductive Investment in Invasive Populations of the Harlequin Ladybird Harmonia axyridis

Reproductive strategy affects population dynamics and genetic parameters that can, in turn, affect evolutionary processes during the course of biological invasion. Life-history traits associated with reproductive strategy are therefore potentially good candidates for rapid evolutionary shifts during invasions. In a series of mating trials, we examined mixed groups of four males from invasive and native populations of the harlequin ladybird Harmonia axyridis mating freely during 48 hours with one female of either type. We recorded the identity of the first male to copulate and after the 48 h-period, we examined female fecundity and share of paternity, using molecular markers. We found that invasive populations have a different profile of male and female reproductive output. Males from invasive populations are more likely to mate first and gain a higher proportion of offspring with both invasive and native females. Females from invasive populations reproduce sooner, lay more eggs, and have offspring sired by a larger number of fathers than females from native populations. We found no evidence of direct inbreeding avoidance behaviour in both invasive and native females. This study highlights the importance of investigating evolutionary changes in reproductive strategy and associated traits during biological invasions.     

Harlequin colour in the Great Dane dog

Breeding data from Eire and Great Britain confirm the hypothesis of Sponenberg (1985) that the harlequin colour of the Great Dane breed of dog is due the combined action of a dominant gene H with the merle gene M in the genotype H+M +. The typical bluish coloration induced by M is modified to white by the action of H. The H gene is a prenatal lethal when homozygous HH and this study offers clear indication that the heterozygous H + interacts with M to reduce the viability of white merle homozygotes H+MM.     

Worldwide Alien Invasion: A Methodological Approach to Forecast the Potential Spread of a Highly Invasive Pollinator

The ecological impacts of alien species invasion are a major threat to global biodiversity. The increasing number of invasion events by alien species and the high cost and difficulty of eradicating invasive species once established require the development of new methods and tools for predicting the most susceptible areas to invasion. Invasive pollinators pose serious threats to biodiversity and human activity due to their close relationship with many plants (including crop species) and high potential competitiveness for resources with native pollinators. Although at an early stage of expansion, the bumblebee species Bombus terrestris is becoming a representative case of pollinator invasion at a global scale, particularly given its high velocity of invasive spread and the increasing number of reports of its impacts on native bees and crops in many countries. We present here a methodological framework of habitat suitability modeling that integrates new approaches for detecting habitats that are susceptible to Bombus terrestris invasion at a global scale. Our approach did not include reported invaded locations in the modeling procedure; instead, those locations were used exclusively to evaluate the accuracy of the models in predicting suitability over regions already invaded. Moreover, a new and more intuitive approach was developed to select the models and evaluate different algorithms based on their performance and predictive convergence. Finally, we present a comprehensive global map of susceptibility to Bombus terrestris invasion that highlights priority areas for monitoring.     

乙型肝炎病毒对HepG2细胞侵袭的影响

目的研究HBV全长对HepG2细胞侵袭相关基因表达及活性的影响,探讨HBV在整体水平对HepG2细胞侵袭的影响。方法采用定量PCR分析HBV对HepG2细胞MMP2、9和TIMP1-4基因转录的影响;通过明胶酶谱及反相明胶酶谱检测MMP2、MMP9及TIMPs的活性;应用体外侵袭小室法检测细胞的侵袭能力。结果HBV的复制可以促进HepG2细胞MMP2、MMP9、TIMP1和TIMP3基因的转录,抑制TIMP4基因转录,增强HepG2细胞MMP2、MMP9的活性并增强细胞中TIMP1、TIMP3功能,HBV稳定复制的细胞具有更强的体外侵袭能力。结论HBV可影响HepG2细胞MMPs和TIMPs的基因转录、表达及功能,促进HepG2细胞的体外侵袭,这可能与HBV相关的HCC侵袭转移密切相关。     

Allee Effect and Control of Lake System Invasion

We consider the model of invasion prevention in a system of lakes that are connected via traffic of recreational boats. It is shown that in presence of an Allee effect, the general optimal control problem can be reduced to a significantly simpler stationary optimization problem of optimal invasion stopping. We consider possible values of model parameters for zebra mussels. The general N-lake control problem has to be solved numerically, and we show a number of typical features of solutions: distribution of control efforts in space and optimal stopping configurations related with the clusters in lake connection structure.     

Biocontrol capabilities of the genus Serratia

Phytochemistry Reviews - This review focuses on the production of natural bioactive products and their biocontrol capabilities of the enterobacterial genus Serratia. Serratia represents a unique...     

Biocontrol agents in the age of molecular biology

The NATO Advanced Research Workshop "Enhancing Biocontrol Agents and Handling Risks" was held in Florence, Italy, 9-15 June 2001.     

Effect of Storage on the Survival and Biocontrol Activity of Pythium oligandrum in Pelleted Sugar Beet Seed

Seeds of sugar beet were pelleted with oospores of Pythium oligandrum and stored for 6 years at 8 20IC. Mycelium of P. oligandrum grew from pelleted seed when plated on cornmeal agar (CMA) within 48 h from 100% of seeds stored for 0, 2 and 4 years, and from 93% of seeds stored for 6 years. The germination of oospores removed from pelleted seed immediately after pelleting was 30% on CMA after 18 h of incubation, but storage gradually reduced germination to only 16% after 48 h of incubation for oospores removed from seed stored for 6 years. The biocontrol activity of P. oligandrum -pelleted seed was also tested after 6 years of storage in mixes of soil naturally infested with Pythium spp. and Aphanomyces cochlioides , and sand. P. oligandrum -pelleted seed had no effect in reducing damping-off due to the combined effect of Pythium spp. and A. cochlioides in 5 and 1% (v/v) soil-sand mixtures. However, in the 1% (v/v) soil-sand mixture, P. oligandrum significantly reduced Pythium spp.-induced damping-off from 33 to 26%.     

Sequestration and Transfer of Cry Entomotoxin to the Eggs of a Predaceous Ladybird Beetle

In the past 10 years, sequestration of Cry toxins and transfer to offspring has been indicated in three insect species in laboratory studies. This work directly demonstrates the sequestration and intergenerational transfer of Cry1F by the parents of the aphidophagous coccinellid predator, Harmonia axyridis, to its offspring. Recently emerged adults (10 individual couples/cage/treatment) were exposed during 20 days to aphids (100 Myzus persicae each day) that fed on a holidic diet containing 20 μg/mL Cry1F (and a control-group). Egg batches and neonate larvae were monitored daily, and counted and weighed for immunodetection of Cry1F by ELISA. At the end of the bioassay, the parents were weighed and analyzed by ELISA. Cry1F was detected in the offspring, both eggs and neonate larvae, of exposed H. axyridis adults. On average the neonate larvae had 60% of the Cry1F concentration of the eggs from the same egg batch. The Cry1F concentration in the adults was positively correlated with the concentration in their eggs. These three results provided independent evidence of transfer to offspring. No detrimental effects of Cry1F were observed on the age of first reproduction, total number of eggs laid per female, age-specific fecundity, egg development time, hatching rate, or fertility rate. The occurrence and generality of intergenerational transfer of Cry toxins should be investigated in the field to determine its potential ecological implications.     

Estimating the Worldwide Extent of Illegal Fishing

Illegal and unreported fishing contributes to overexploitation of fish stocks and is a hindrance to the recovery of fish populations and ecosystems. This study is the first to undertake a world-wide analysis of illegal and unreported fishing. Reviewing the situation in 54 countries and on the high seas, we estimate that lower and upper estimates of the total value of current illegal and unreported fishing losses worldwide are between $10 bn and $23.5 bn annually, representing between 11 and 26 million tonnes. Our data are of sufficient resolution to detect regional differences in the level and trend of illegal fishing over the last 20 years, and we can report a significant correlation between governance and the level of illegal fishing. Developing countries are most at risk from illegal fishing, with total estimated catches in West Africa being 40% higher than reported catches. Such levels of exploitation severely hamper the sustainable management of marine ecosystems. Although there have been some successes in reducing the level of illegal fishing in some areas, these developments are relatively recent and follow growing international focus on the problem. This paper provides the baseline against which successful action to curb illegal fishing can be judged.     

Worldwide genetic analysis of the CFTR region

Mutations at the cystic fibrosis transmembrane conductance regulator gene (CFTR) cause cystic fibrosis, the most prevalent severe genetic disorder in individuals of European descent. We have analyzed normal allele and haplotype variation at four short tandem repeat polymorphisms (STRPs) and two single-nucleotide polymorphisms (SNPs) in CFTR in 18 worldwide population samples, comprising a total of 1,944 chromosomes. The rooted phylogeny of the SNP haplotypes was established by typing ape samples. STRP variation within SNP haplotype backgrounds was highest in most ancestral haplotypes-although, when STRP allele sizes were taken into account, differences among haplotypes became smaller. Haplotype background determines STRP diversity to a greater extent than populations do, which indicates that haplotype backgrounds are older than populations. Heterogeneity among STRPs can be understood as the outcome of differences in mutation rate and pattern. STRP sites had higher heterozygosities in Africans, although, when whole haplotypes were considered, no significant differences remained. Linkage disequilibrium (LD) shows a complex pattern not easily related to physical distance. The analysis of the fraction of possible different haplotypes not found may circumvent some of the methodological difficulties of LD measure. LD analysis showed a positive correlation with locus polymorphism, which could partly explain the unusual pattern of similar LD between Africans and non-Africans. The low values found in non-Africans may imply that the size of the modern human population that emerged "Out of Africa" may be larger than what previous LD studies suggested.     

类风湿性关节炎成纤维样滑膜(FLS)细胞中DDR2相互作用分子的筛选鉴定及其对FLS细胞侵袭能力的影响

目的:在类风湿性关节炎(RA)成纤维样滑膜(FLS)细胞中筛选并鉴定盘状结构域受体2(DDR2)的相互作用蛋白,并研究其对FLS细胞侵袭能力的影响。方法:首先利用免疫沉淀结合SDS-PAGE分离鉴定DDR2互作蛋白波形蛋白,进而采用免疫沉淀和激光共聚焦实验,进一步验证波形蛋白是DDR2的相互作用蛋白,最后采用Transwell实验考察波形蛋白对RA FLS细胞侵袭能力的影响。结果:Ⅱ型胶原刺激引起RA FLS细胞中DDR2的磷酸化水平升高,DDR2被活化,活化前后共有8个DDR2相互作用蛋白发生变化,经质谱分析,其中变化最大的是波形蛋白和膜联蛋白A2;在HEK293T细胞中,免疫共沉淀结果显示Fc DDR2与波形蛋白存在相互作用;激光共聚焦结果显示在RA FLS细胞中,DDR2和波形蛋白存在共定位;下调RA FLS细胞中波形蛋白的表达后,细胞的侵袭能力较对照组显著下降。结论:波形蛋白是DDR2的相互作用蛋白,Ⅱ型胶原可引起RA FLS细胞的DDR2磷酸化水平升高,并通过波形蛋白促进RA FLS细胞的侵袭。     

生防真菌基因标记技术研究进展

生防真菌在环境中的检测是生物防治研究中的一个重要问题,基因标记是检测生防真菌的一种新技术。概述基因标记的概念、基因标记的载体质粒和标记基因、基因标记的方法及其在生防真菌中的应用情况。     

水果采后生物防治拮抗机理的研究进展

近20年来,人们在水果采后生物防治领域里取得了显著的成绩。目前巳经分离获得了数百种对水果采后主要病害有明显拮抗效果的生物拮抗菌。很多拮抗菌经过生产中试,有的巳制成了生物药剂用于水果采后的商业化处理。有关拮抗菌的抑病机理研究也一直贯穿于采后生物防治的整个发展历程。本文在探讨了水果采后拮抗菌剂病机理的基础上,回顾了该领域的研究进展,并从拮抗菌与病原菌发生拮抗作用的4条主要途径入手,对该领域的研究成果及研究方法作一简要总结。     

The Effect of Spatial Distributions of Mycoparasites on Biocontrol Efficacy: a Modelling Approach

The spatial distribution of propagules in soil is an important factor in determining the ability of mycoparasites to control soilborne plant pathogens. The assumptions of uniform, random and aggregated propagule distribution were used to evaluate the importance of spatial distribution patterns of propagules of a mycoparasite. For the random and uniform cases explicit expressions were obtained for the average distance between propagules. Average distances among propagules are 40-50% smaller for the random compared to the uniform distribution. For the aggregated case no explicit expression is possible and numerical simulations were used to generate spatial distributions. The consequences for host inactivation by the mycoparasite were evaluated using a simple model of omnidirectional and constant growth of the mycoparasite. A random distribution of propagules gave a considerably slower rate of inactivation than the uniform distribution. Numerical simulations were made to generate comparable patterns of host inactivation for aggregated distributions in which propagule clusters were located at random in three-dimensional space and the distances between propagules with centres followed a normal distribution. The number of propagule centres and propagules/centre varied for a given inoculum density. Parameters were estimated from published data for sclerotia of Sclerotium minor inactivation at different densities of macroconidia of Sporidesmium sclerotivorum. Differences in host inactivation between the uniform and random distributions were small but both gave poor predictions of the field data at low and high densities. The aggregated distribution gave an improved fit for the higher propagule densities but no improvement at the lower. In studying the dynamics of mycoparasites it may be more significant epidemiologically to design treatments based on differences in mean distances between propagules rather than population densities. Density-dependent effects on growth rate need more attention in models and studies on mycoparasite ecology.     

Calpain2对肝癌细胞浸润和转移能力的影响

目的：肝细胞癌（HCC）是一类常见的恶性肿瘤,主要表现为进展迅速、易复发及预后不良。侵袭转移作为肝癌的最主要的恶性表型,是造成较高致死率的主要原因。Calpain是钙激活中性蛋白酶,广泛参与了细胞多种生命过程。其中Calpainl和Calpain2是Calpain家族主要成员,对于维持肿瘤细胞恶性表型有重要作用。本研究通过RNA干涉技术下调人肝癌Huh7细胞中Calpain2基因的表达,检测下调Calpain2对人肝癌Huh7细胞黏附,侵袭和迁移能力的影响,明确Calpain2在人肝癌细胞浸润和转移过程中的作用。方法：合成Calpain2的RNAi片段,瞬时转染人肝癌细胞Huh7,降低Hull7细胞中Calpain2的表达,运用细胞黏附实验,细胞侵袭实验及划痕愈合实验检测干涉Calpain2对肝癌细胞的黏附,侵袭和迁移能力的影响。结果：合成Calpain2的RNAi片段。瞬时转染人肝癌细胞Huh73,36小时后,细胞中Calpain2的蛋白水平明显下降,干涉Calpain2后人肝癌细胞Huh7的黏附率,侵袭率及划痕修复率的显著下降。结论：以上实验结果表明Calpain2能够促进肝癌细胞黏附,侵袭及划痕修复能力,Calpain2能够促进肝癌细胞的浸润和转移的作用,是肝癌发生发展过程中的肿瘤促进因子。因此,Calpain2可以作为抑制肝癌侵袭和转移的潜在靶点,靶向Call＇ain2的药物可能成为治疗肝癌侵袭转移的新方法。