Asaff Ali, Cerda-García-Rojas Carlos, de la Torre Mayra
Departamento de Biotecnología y Bioingeniería, CINVESTAV, Mexico City, Mexico.
Appl Microbiol Biotechnol. 2005 Sep;68(4):542-7. doi: 10.1007/s00253-005-1909-2. Epub 2005 Oct 26.
Several entomopathogenic fungi produce toxins that could be used as bioinsecticides in integrated pest management programs. Paecilomyces fumosoroseus is currently used for the biological control of the whiteflies Bemisia tabaci and B. argentifolii. Supernatants from submerged batch culture, where the fungus produced abundant dispersed mycelium, conidia and blastospores, were toxic to the whitefly nymphs. The most abundant metabolite was purified by HPLC and identified by mass spectrometry and NMR as dipicolinic acid. Both the dipicolinic acid produced by the fungus and the chemically synthesized compound had insecticidal activity against third-instar nymphs of the insect. Dipicolinic acid was toxic to the whitefly nymphs in bioassays involving topical applications. In submerged culture, the specific growth rate of P. fumosoroseus was 0.054 h-1, the specific glucose consumption rate was 0.1195 g g-1 h-1 and the specific dipicolinic acid production rate was 0.00012 g g-1 h-1. Dipicolinic acid was detected after 24 h when the fungus started growing; and dipicolinic acid production was directly correlated with fungal growth. Nevertheless, the yield was low and the maximal concentration was only 0.041 g l-1. The maximal concentrations of conidia and blastospores (per milliliter) were 1.4x10(8) and 7x10(7), respectively.
几种昆虫病原真菌产生的毒素可作为生物杀虫剂用于综合虫害管理计划。玫烟色拟青霉目前用于生物防治烟粉虱和银叶粉虱。在深层分批培养中，该真菌产生大量分散的菌丝体、分生孢子和芽生孢子，其培养上清液对粉虱若虫有毒。通过高效液相色谱法纯化了最丰富的代谢产物，并通过质谱和核磁共振鉴定为吡啶二羧酸。该真菌产生的吡啶二羧酸和化学合成的化合物对该昆虫的三龄若虫均具有杀虫活性。在涉及局部应用的生物测定中，吡啶二羧酸对粉虱若虫有毒。在深层培养中，玫烟色拟青霉的比生长速率为0.054 h-1，比葡萄糖消耗速率为0.1195 g g-1 h-1，比吡啶二羧酸产生速率为0.00012 g g-1 h-1。当真菌开始生长24小时后检测到吡啶二羧酸；吡啶二羧酸的产生与真菌生长直接相关。然而，产量较低，最大浓度仅为0.041 g l-1。分生孢子和芽生孢子的最大浓度（每毫升）分别为1.4x10(8)和7x10(7)。
