Comparative analysis of the production of insecticidal and melanizing macromolecules by strains of Beauveria spp.:: in vivo studies
Comparative analysis of the production of insecticidal and melanizing macromolecules by strains of Beauveria spp.:: in vivo studies
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DOI：
10.1016/j.jip.2004.03.001
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发表时间：
2004-03-01
影响因子：
3.4
通讯作者：
Vey, A
中科院分区：
文献类型：
--
作者：
Fuguet, R;Vey, A
通过将 8 x 10(2) 个分生孢子注射到鳞翅目大蜡螟幼虫的血腔中，对 11 种白僵菌菌株和另外 5 种白僵菌进行了测试，目的是分析它们体内产生毒素的活性。尽管强毒株杀死 100% 的昆虫的速度略有不同（4-6 天），但分离株引起的宿主黑色化的模式和强度存在显着差异。白僵菌属的大多数分离株。引起体壁和气管壁角质层快速而强烈的黑色化，遵循三种模式之一。另一小组从玉米螟中分离出的两种球孢白僵菌菌株诱导非常弱的黑化或不诱导黑化。白僵菌菌株618和101分别被选为“黑化”和“非黑化”菌株的模型。在被这两种分离株感染的幼虫中，皮下和气管上皮细胞以及血细胞的超微结构改变被认为至少部分是由真菌毒素引起的。然而，它们对皮下组织精细结构的影响是不同的。注射从感染白僵菌 618 的昆虫的血淋巴中获得的血清显示，它们具有与真菌病期间相似的杀虫、黑化和细胞毒性作用。对粗血清制备的级分进行色谱研究和生物测定，可以部分鉴定体内真菌分泌的有毒分子。如蛋白酶处理所示，它们是蛋白质，不耐热，带负电荷，并且不被 α-(D)-甘露糖或 α-(D)-葡萄糖糖基化。如果菌株 B. bassiana 618 产生黑化大分子，这是真菌病期间分泌的体内毒素，则分离株 101 的作用方式是不同的。它杀死宿主的能力取决于活跃的菌丝发育和低分子量毒素的产生。 (C) 2004 Elsevier Inc. 保留所有权利。
Eleven strains of Beauveria bassiana, and a further five species of Beauveria sp., were tested by injection of 8 x 10(2) conidia into the haemocoel of the larvae of the lepidopteran Galleria mellonella with the aim of analysing their toxin producing activity in vivo. Although the virulent strains killed 100% of the insects at slightly different rates (4-6 days) there were significant differences in the pattern and intensity of host melanization caused by isolates. The majority of the isolates of Beauveria spp. induced a fast and intense melanization of the cuticle of the integument and of tracheal wall, wich followed one of three patterns. Another small group of two B. bassiana strains, isolated from Ostrinia nubilalis, induced very weak or no melanization. Strains 618 and 101 of B. bassiana, were selected as models of "melanizing" and "non-melanizing" strains, respectively. Ultrastructural alterations of cells of hypodermal and tracheal epithelium and of haemocytes, assumed to be at least partially caused by fungal toxins, were revealed in larvae infected by both isolates. However, their effects on the fine structure of the hypodermis were different. Injection of sera obtained from haemolymph of insects infected with B. bassiana 618 showed that they have insecticidal, melanizing, and cytotoxic effects similar to those Occurring during mycosis. Chromatographic studies and bioassays with fractions prepared from crude serum have allowed a partial identification of the toxic molecules secreted by the fungus in vivo. They are proteinaceous, as shown by protease treatments, thermolabile, negatively charged, and not glycosylated with alpha-(D)-mannose or alpha-(D)-glucose. If strain B. bassiana 618 produces melanizing macromolecules which are vivotoxins secreted during the mycosis, the mode of action of isolate 101 is different. Its capacity to kill the host depends on active mycelial development, and on the production of low molecular weight toxins. (C) 2004 Elsevier Inc. All rights reserved.