Wolbachia and cytoplasmic incompatibility in the California Culex pipiens mosquito species complex: parameter estimates and infection dynamics in natural populations.
Wolbachia and cytoplasmic incompatibility in the California Culex pipiens mosquito species complex: parameter estimates and infection dynamics in natural populations.
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作者：
J. Rasgon;T. Scott
在母系遗传的细菌共生体，如沃尔巴克氏体，导致细胞质不相容性（CI;孵化率降低）时，受感染的男性与未感染的女性交配，可用于控制病媒传播的疾病的程序，它是必不可少的，以了解他们的感染动力学在自然节肢动物媒介种群。我们的研究有四个目标：（1）定量测定在加州尖音库蚊复合群中传播的Wolbachia菌株的数量;（2）调查Wolbachia在加州自然种群中的感染频率和分布;（4）利用这些数值来估计平衡水平，并将预测的感染流行水平与自然界中观察到的感染流行水平进行比较。菌株特异性PCR，wsp基因测序和交叉实验表明，一个单一的沃尔巴克氏体菌株感染加州Cx。pipiens。沿沿着1000 km的南北样带采样2年的所有种群的感染频率接近或处于固定。全国感染率为99.4%。在实验室和田间条件下，不亲和杂交100%不育。不育性随实验室雄性年龄的增长而降低，但可忽略不计。在实验室或田间条件下，感染对雌性生殖力没有显著影响。实验室垂直传播率> 99%，田间垂直传播率约为98.6%。使用现场数据，模型预测，如果感染超过1.4%以上的不稳定平衡点，沃尔巴克氏体将传播到固定。我们的估计准确地预测了自然人群中的感染频率。如果某些技术障碍可以克服，我们的数据表明，沃尔巴克氏体可以入侵载体种群的一部分，应用转基因策略减少病媒传播的疾病。
Before maternally inherited bacterial symbionts like Wolbachia, which cause cytoplasmic incompatibility (CI; reduced hatch rate) when infected males mate with uninfected females, can be used in a program to control vector-borne diseases it is essential to understand their dynamics of infection in natural arthropod vector populations. Our study had four goals: (1) quantify the number of Wolbachia strains circulating in the California Culex pipiens species complex, (2) investigate Wolbachia infection frequencies and distribution in natural California populations, (3) estimate the parameters that govern Wolbachia spread among Cx. pipiens under laboratory and field conditions, and (4) use these values to estimate equilibrium levels and compare predicted infection prevalence levels to those observed in nature. Strain-specific PCR, wsp gene sequencing, and crossing experiments indicated that a single Wolbachia strain infects Californian Cx. pipiens. Infection frequency was near or at fixation in all populations sampled for 2 years along a >1000-km north-south transect. The combined statewide infection frequency was 99.4%. Incompatible crosses were 100% sterile under laboratory and field conditions. Sterility decreased negligibly with male age in the laboratory. Infection had no significant effect on female fecundity under laboratory or field conditions. Vertical transmission was >99% in the laboratory and approximately 98.6% in the field. Using field data, models predicted that Wolbachia will spread to fixation if infection exceeds an unstable equilibrium point above 1.4%. Our estimates accurately predicted infection frequencies in natural populations. If certain technical hurdles can be overcome, our data indicate that Wolbachia can invade vector populations as part of an applied transgenic strategy for vector-borne disease reduction.