Biochemical Investigations of the Host-Parasite Relationship of Mosquitos and the Parasite Fungus 'Lagenidium sp'.
Annual summary rept. 1 Jul 74-1 Jul 75,
NORTH CAROLINA UNIV CHAPEL HILL BIOCHEMISTRY LAB
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The mosquito parasite Lagenidium giganteum was found to possess no detectable sterols, and the organism grew as a saprobe. The fungus took up phytosterols, such as beta-sitosterol, campesterol, ergosterol and desmosterol and these substances were found to be essential for zoospore production and thence conversion of the fungus to a mosquito parasite. Oils that are rich in three phytosterols, beta-sitosterol, campesterol and stigmasterol were found to be very effective zoospore producers. These sterols are found in soy bean oil and in hemp seed oil in these approximate ratios. Sterol preparations from hemp seed were very effective in inducing zoospore production, and this has confirmed the authentic sterols tested. The phytosterols are found in many insects and it was hypothesized that these substances are the keystone to this particular parasitism. This is the first Lagenidium species ever shown to require sterols for zoospore production.