Cuticular differences associated with aridity acclimation in African malaria vectors carrying alternative arrangements of inversion 2La.
Cuticular differences associated with aridity acclimation in African malaria vectors carrying alternative arrangements of inversion 2La.
复制标题
DOI：
10.1186/1756-3305-7-176
复制
发表时间：
2014-04-10
影响因子：
3.2
通讯作者：
Syed Z
中科院分区：
文献类型：
--
作者：
Reidenbach KR;Cheng C;Liu F;Liu C;Besansky NJ;Syed Z
非洲的主要疟疾传播媒介。冈比亚和安哥拉。coluzzii，在2号染色体左臂（2La/2L+a）上具有非随机分布的反转多态性。基因组测序研究支持强自然选择在保持2La反转频率沿干旱环境梯度的陡峭曲线中的作用，生理学研究直接表明2La与耐热和干燥耐受性有关，但精确的遗传基础和潜在的行为和生理机制尚不清楚。由于昆虫的角质层是水分流失的主要屏障，角质层厚度和/或表皮防水性的差异与不同的2La排列有关，这可能有助于解释昆虫的干旱性差异。为了验证这个假设，安。冈比亚和安哥拉。在其他同序列和共享的遗传背景下，建立了固定的2La排列（2La或2L+a）的coluzzii。收集和分析在控制的环境条件下（良性或干旱）饲养的成蚊羽化后8天。采用扫描电镜测量了表皮厚度，气相色谱-质谱法测定了表皮碳氢化合物（CHC）组成。去除体重异速生长效应后，不同2La核型间平均角质层厚度存在差异，而不同环境间无差异。此外，皮肤的角质层较厚。coluzzii 2La核型与已知的相对于2L+a较高的失水率相反。另一方面，不同核型和环境条件下个体CHC和总体CHC谱的数量差异与先前生理研究的预期一致。我们的研究结果表明，2La反转的不同排列方式与角质层厚度和CHC组成的差异有关，但只有CHC组成似乎与抗旱性有关。CHC组成的差异与之前的研究结果一致，即2L+a核型在闭合后8天的水分损失率较低，这表明CHC组成是维持这种遗传背景下水分平衡的重要策略，而不是2La。尽管在第8天水分流失率较高，但2La核型较高的体内水分含量赋予了与2L+a核型相当的抗干旱性水平。
Principal malaria vectors in Africa, An. gambiae and An. coluzzii, share an inversion polymorphism on the left arm of chromosome 2 (2La/2L+a) that is distributed non-randomly in the environment. Genomic sequencing studies support the role of strong natural selection in maintaining steep clines in 2La inversion frequency along environmental gradients of aridity, and physiological studies have directly implicated 2La in heat and desiccation tolerance, but the precise genetic basis and the underlying behavioral and physiological mechanisms remain unknown. As the insect cuticle is the primary barrier to water loss, differences in cuticle thickness and/or epicuticular waterproofing associated with alternative 2La arrangements might help explain differences in desiccation resistance. To test that hypothesis, two subcolonies of both An. gambiae and An. coluzzii were established that were fixed for alternative 2La arrangements (2La or 2L+a) on an otherwise homosequential and shared genetic background. Adult mosquitoes reared under controlled environmental conditions (benign or arid) for eight days post-eclosion were collected and analyzed. Measurements of cuticle thickness were made based on scanning electron microscopy, and cuticular hydrocarbon (CHC) composition was evaluated by gas chromatography–mass spectrometry. After removing the allometric effects of body weight, differences in mean cuticle thickness were found between alternative 2La karyotypes, but not between alternative environments. Moreover, the thicker cuticle of the An. coluzzii 2La karyotype was contrary to the known higher rate of water loss of this karyotype relative to 2L+a. On the other hand, quantitative differences in individual CHCs and overall CHC profiles between alternative karyotypes and environmental conditions were consistent with expectation based on previous physiological studies. Our results suggest that alternative arrangements of the 2La inversion are associated with differences in cuticle thickness and CHC composition, but that only CHC composition appears to be relevant for desiccation resistance. Differences in the CHC composition were consistent with previous findings of a lower rate of water loss for the 2L+a karyotype at eight days post-eclosion, suggesting that CHC composition is an important strategy for maintaining water balance in this genetic background, but not for 2La. Despite a higher rate of water loss at eight days, higher body water content of the 2La karyotype confers a level of desiccation resistance equivalent to that of the 2L+a karyotype.
登录
查看更多内容
影响因子：
56.9
作者：
Balanya, Joan;Oller, Josep M.;Serra, Luis
通讯作者：
Serra, Luis
影响因子：
3.2
作者：
Ayala, Diego;Caro-Riano, Harling;Fontenille, Didier
通讯作者：
Fontenille, Didier
影响因子：
3.8
作者：
della Torre, A;Tu, ZJ;Petrarca, V
通讯作者：
Petrarca, V
影响因子：
1.9
作者：
Benoit, J. B.;Lopez-Martinez, G.;Denlinger, D. L.
通讯作者：
Denlinger, D. L.
影响因子：
3.8
作者：
Caputo, B.;Dani, F. R.;della Torre, A.
通讯作者：
della Torre, A.