An unlikely silk: the composite material of green lacewing cocoons.
An unlikely silk: the composite material of green lacewing cocoons.
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DOI：
10.1021/bm8005853
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发表时间：
2008-10
影响因子：
6.2
通讯作者：
Sarah Weisman;H. Trueman;S. Mudie;J. Church;T. Sutherland;V. Haritos
中科院分区：
文献类型：
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作者：
Sarah Weisman;H. Trueman;S. Mudie;J. Church;T. Sutherland;V. Haritos
蜘蛛通常生产多种类型的丝;然而，常识认为昆虫物种生产一种类型的丝。这项工作报告说，绿色草蛉（Mallada signata，脉翅目）产生两个不同的类丝。我们确定并测序的基因编码的主要蛋白质成分的幼虫草蛉茧丝，并证明它是无关的成年草蛉卵柄丝。茧丝蛋白的大小为49 kDa，富含丙氨酸（>40%），并且含有α-螺旋二级结构。末龄草蛉幼虫纺出直径约2微米的蛋白质纤维，形成一个松散的茧。在茧构造的第二阶段，昆虫放下一层脂质内壁，利用纤维作为支架。我们建议，丝蛋白纤维提供的复合草蛉茧的机械强度，而脂质层提供了一个屏障，在化蛹过程中的水分流失。
Spiders routinely produce multiple types of silk; however, common wisdom has held that insect species produce one type of silk each. This work reports that the green lacewing ( Mallada signata, Neuroptera) produces two distinct classes of silk. We identified and sequenced the gene that encodes the major protein component of the larval lacewing cocoon silk and demonstrated that it is unrelated to the adult lacewing egg-stalk silk. The cocoon silk protein is 49 kDa in size and is alanine rich (>40%), and it contains an alpha-helical secondary structure. The final instar lacewing larvae spin protein fibers of approximately 2 microm diameter to construct a loosely woven cocoon. In a second stage of cocoon construction, the insects lay down an inner wall of lipids that uses the fibers as a scaffold. We propose that the silk protein fibers provide the mechanical strength of the composite lacewing cocoon whereas the lipid layer provides a barrier to water loss during pupation.