成熟时滞对Wolbachia在蚊子种群中的传播影响研究

建立了一个Wolbachia在蚊子种群中的传播模型,并考虑蚊子种群的成熟时滞,主要研究时滞对Wolbachia传播的影响.首先,通过理论分析发现零解是不稳定的;其次,理论分析了常数时滞对模型动力学行为的影响,发现Wolbachia会完全入侵蚊子种群;最后,通过数值模拟讨论了周期时滞对模型动力学行为的影响,发现Wolbachia部分替代周期解和完全替代周期解都有可能存在,与出生率和历史值有关.     

夏季来了注意猪场蚊子

蚊子可以传播许多疫病,如附红细胞体、猪乙型脑炎、猪弓形体及其他血液寄生虫病,大量的蚊子叮咬也会骚扰猪的生长发育,因此,我们应注意夏季猪场蚊子的杀灭工作. 我们经常使用捕捉、拍打、黏附等方法.也有人使用纱窗或蚊帐之类的防蚊方法,但存在通风不足等隐患.利用电子灭蚊灯也不失为一种好方法.     

具有不育控制的埃及伊蚊种群模型的全局动态

给出了一个描述具有不育雄蚊作为生物控制的埃及伊蚊种群动力系统的模型.研究了边界平衡点及正平衡点存在和稳定的条件,得到了当正平衡点不存在时,边界平衡点全局渐近稳定的条件,即投放不育雄蚊使得野生蚊子种群灭亡的充分条件.     

用猪笼草捉蚊子,蚊子“呸”一声

<正>夏天来了,恼人的蚊子也来了。对付蚊子的方法层出不穷,但是想要把家里的蚊子赶尽杀绝,还真没有什么万全的办法。眼见蚊子来袭,绿植商家开始这样叫卖:"夏天经常被蚊子咬怎么办?养盆猪笼草呀!用猪笼草灭蚊守夏,效果好着呐!"猪笼草是灭蚊神器?不错不错,赶紧买一盆试试!别忙,咱们还是先把猪笼草了     

蚊子之死

晚上,我被蚊子吵醒。“去咬她吧,不要咬我。”我向蚊子推荐我熟睡中的老婆。“我想咬谁就咬谁,你管得着吗?”蚊子嗡嗡着说。“去咬她吧,咬一下给你1毛钱,怎么样?”蚊子想了想,答应了。第二天早晨起来,我统计出自己少了1块钱,老婆统计出自己多了10个包。好在我老婆睡得死,挨咬时     

蚊子竞技

有三只蚊子在炫耀自己的飞行技术,臭屁连天,吵得面红耳赤,却分不出个胜负,于是它们决定各自“秀”一段。英国蚊子首先发难。只见它飞向一只青蛙,在它附近转了几圈,回来时,只见青蛙的舌头打了一个活结,它骄傲地说“:告诉你们!在我老家,若没有这种本事,马上就会完蛋的!”美国蚊子     

蚊子对养殖动物的危害与灭蚊

一、蚊子对养殖动物的危害 只有雌蚊才叮咬哺乳动物.它们每隔3～4天须吸一次血,以取得制造卵子所需的蛋白质;而雄蚊则主要摄食花蜜、植物的汁液.很多动物没有毛羽遮挡,一到晚上就成了蚊子攻击的目标.吸血给动物生长发育造成极大为害.猪被蚊子骚扰后,烦躁不安,厌食,生长变慢,料耗提高,抗病力降低,小猪出现腹泻.牛、羊、马被蚊子骚扰后,很多出现消瘦、皮肤病严重.     

猪场蚊子中乙型脑炎病毒的RT-PCR检测

收集湖北省与安徽省部分猪场的蚊子样本,用RT-PCR检测蚊子样本是否携带有乙型脑炎病毒,并对猪群乙型脑炎病毒抗体进行了检测.结果表明,53份蚊子样品中乙型脑炎病毒阳性样品为44份,表明这些猪场的蚊子广泛携带有乙型脑炎病毒.从阳性PCR产物中随机选出8个,并将其克隆到pEASY-T1载体中,得到5个阳性重组质粒,进行序列测定和进化树分析,结果表明阳性蚊子样本携带的都是基因Ⅲ型乙型脑炎病毒.猪场的1 401份血清样品的乙型脑炎病毒抗体阳性率为57.7％,说明这些猪场猪群的乙型脑炎病毒感染率较高.     

光叶蚊子草挥发油成分GC-MS分析

用气相色谱-质谱法分析光叶蚊子草的挥发油化学成分.采用水蒸气蒸馏法从光叶蚊子草中提取挥发油.用归一化法测定其百分含量,并用气相色谱-质谱法鉴定化学成分.共鉴定了23个成分,占挥发油总量的78.53%以上.本方法稳定可靠,重现性好,适用于中药挥发油的化学成分分析     

蚊子及防治技术的探讨

1概况1.1环境现状中核四〇四有限公司(甘肃矿区办事处)担负着国家重点核技术科研项目,生产基地建有乏燃料后处理重点厂房、设施设备,所以这里是员工上班、生活和学习的重要场所。然而,这里现在成了蚊虫四处肆虐、活动猖獗的地方,到了2011年,这种状况尤为突出,蚊子对人们的身心健康造成了严重的影响,人们聊天之余,无不谈到蚊子的问题,已经到了"谈蚊色变"的地步。举个例子,你要是光着膀子走在大街上,不一会儿蚊子会爬满你裸露的皮肤,随意一巴掌下去,能拍到4～5只蚊子。     

Effect of kinetin on Paramecium caudatum under varying culture conditions

A strain of Mayaro virus has been isolated in Trinidad from the mosquito Mansonia venezuelensis. This is the first record of isolation of this agent from naturally infected mosquitoes, caught in the wild.     

Genetic loci affecting resistance to human malaria parasites in a West African mosquito vector population

Successful propagation of the malaria parasite Plasmodium falciparum within a susceptible mosquito vector is a prerequisite for the transmission of malaria. A field-based genetic analysis of the major human malaria vector, Anopheles gambiae, has revealed natural factors that reduce the transmission of P. falciparum. Differences in P. falciparum oocyst numbers between mosquito isofemale families fed on the same infected blood indicated a large genetic component affecting resistance to the parasite, and genome-wide scanning in pedigrees of wild mosquitoes detected segregating resistance alleles. The apparently high natural frequency of resistance alleles suggests that malaria parasites (or a similar pathogen) exert a significant selective pressure on vector populations.     

濒危植物大花杓兰种子离体培养条件初探

[目的]该研究旨在探讨野生大花杓兰种子人工大量繁殖的培养条件。[方法]以大花杓兰半成熟种子为试验材料,对其在无菌条件下的萌发进行了研究。[结果]结果表明,0.5%的NaClO预处理种子160 min,pH 5.8及添加0.5 mg/L 6-BA和马铃薯浸提物的Harvais培养基是大花杓兰种子无菌萌发的最佳培养条件。[结论]该研究为大花杓兰种子的组培繁殖提供依据。     

稻田中性昆虫对群落食物网的调控作用

目的明确中性昆虫蚊虫在茶园节肢动物群落中的地位和作用,为茶园害虫综合防治、科学合理地保护和利用自然天敌提供科学依据。方法对2015、2016年的白毫早茶园和乌牛早茶园及2014、2015年安吉白茶茶园蚊虫及主要害虫与8种蜘蛛类群的关系进行分析,用灰色关联度法和时间生态位相似性系数法分析蚊虫及5种害虫与蜘蛛类群在数量上和时间上的关系,利用通径分析法分析蚊虫及5种害虫对蜘蛛类群的直接和间接作用,运用决策系数R²(j)大小判别蚊虫和5种害虫对蜘蛛类群的作用大小次序。对上述结果进行标准化处理,综合评判,求得与蜘蛛类天敌作用大的前3位食饵。结果在天敌食饵的数量、发生时间与天敌关系的密切程度上,第1位的食饵是双斑长跗萤叶甲,第2位是蚊虫,第3位是茶蚜。3种茶园2个年度的R²(j)值标准化处理综合分析得出：对蜘蛛类天敌作用最大的第1位食饵是假眼小绿叶蝉,第2位是蓟马,第3位是蚊虫。结论由蚊虫作为天敌食饵的地位看出,蚊虫替代害虫对蜘蛛的生长、繁殖起到很大作用。     

A G1 glycoprotein epitope of La Crosse virus: a determinant of infection of Aedes triseriatus

Arthropod-borne viruses (arboviruses) have specific vector-vertebrate host cycles in nature. The molecular basis of restriction of virus replication to a very limited number of vector species is unknown, but the present study suggests that viral attachment proteins are important determinants of vector-virus interactions. The principal vector of La Crosse (LAC) virus is the mosquito Aedes triseriatus, and LAC virus efficiently infects the mosquito when ingested. However, a variant (V22) of LAC virus, which was selected by growing the virus in the presence of a monoclonal antibody, was markedly restricted in its ability to infect Ae. triseriatus when it was ingested. Only 15% of the mosquitoes that ingested V22 became infected and 5% of these developed disseminated infections. In contrast, 89% of the mosquitoes that ingested LAC became infected and 74% developed disseminated infections. When V22 was passed three times in mosquitoes by feeding, a revertant virus, V22M3, was obtained that infected 85% of Ae. triseriatus ingesting this virus. In addition, V22M3 regained the antigenic phenotype and fusion capability of the parent LAC virus. These results suggest that the specificity of LAC virus-vector interactions is markedly influenced by the efficiency of the fusion function of the G1 envelope glycoprotein operating at the midgut level in the arthropod vector.     

Genetic analysis of the human malaria parasite Plasmodium falciparum

Malaria parasites are haploid for most of their life cycle, with zygote formation and meiosis occurring during the mosquito phase of development. The parasites can be analyzed genetically by transmitting mixtures of cloned parasites through mosquitoes to permit cross-fertilization of gametes to occur. A cross was made between two clones of Plasmodium falciparum differing in enzymes, drug sensitivity, antigens, and chromosome patterns. Parasites showing recombination between the parent clone markers were detected at a high frequency. Novel forms of certain chromosomes, detected by pulsed-field gradient gel electrophoresis, were produced readily, showing that extensive rearrangements occur in the parasite genome after cross-fertilization. Since patients are frequently infected with mixtures of genetically distinct parasites, mosquito transmission is likely to provide the principal mechanisms for generating parasites with novel genotypes.     

Isolation of St. Louis encephalitis virus from overwintering Culex pipiens mosquitoes

Two strains of St. Louis encephalitis virus were isolated from overwintering mosquitoes collected in Maryland and Pennsylvania during January and February 1977. There isolations from Culex pipiens constitute evidence that a mosquito-borne flavivirus can persist in a vector mosquito in temperate climates during the winter season.     

一种普通小麦光温敏不育系的发现及初步研究

291S是笔者在普通小麦新品系西农291中发现的自然突变的雄性不育材料。本研究对291S的育性转换特性、雄性败育特点及不育性的遗传规律进行了初步分析。分期播种试验表明,291S是一种光温敏雄性不育系,秋播短日低温条件下表现为部分可育,春播长日高温条件下表现为高度不育,其可繁性和不育性经选择可以得到有效改良。291S在一定的光温条件诱导下会出现雄蕊心皮化现象。花粉粒I2-KI染色发现,291S在不育阶段花粉败育类型以圆败为主。遗传分析表明,291S可能为隐性核不育类型,其不育性由一对主效基因控制,还受到微效基因的修饰作用。291S类型的光温敏不育材料在两系法杂交小麦育种上具有良好的应用前景。     

Natural malaria infection in Anopheles gambiae is regulated by a single genomic control region

We surveyed an Anopheles gambiae population in a West African malaria transmission zone for naturally occurring genetic loci that control mosquito infection with the human malaria parasite, Plasmodium falciparum. The strongest Plasmodium resistance loci cluster in a small region of chromosome 2L and each locus explains at least 89% of parasite-free mosquitoes in independent pedigrees. Together, the clustered loci form a genomic Plasmodium-resistance island that explains most of the genetic variation for malaria parasite infection of mosquitoes in nature. Among the candidate genes in this chromosome region, RNA interference knockdown assays confirm a role in Plasmodium resistance for Anopheles Plasmodium-responsive leucine-rich repeat 1 (APL1), encoding a leucine-rich repeat protein that is similar to molecules involved in natural pathogen resistance mechanisms in plants and mammals.