Resistance developed by mosquitoes to available chemical insecticides and restrictions on their use favor the development of host-specific microbial agents for operational mosquito control. The proposed research continues investigation of fermentation production, storage, activation and application of the sexual stage (oospores) of Lagenidium giganteum. This is the only eukaryotic biological control agent of medically important arthropods with immediate potential for use in operational control programs. Conventional approaches to yield optimization using stirred tank fermentation will focus on alteration will focus on alteration of culture parameters at specific developmental stages of the fungus. Response surface analysis will be used to accelerate the development of optimum oospore yields. Modification of fermentation conditions to optimize synthesis of specific compounds associated with oosporogenesis will be attempted. Storage and activation protocols will be modified to limit premature abortion of converted oospores. Multi- hectare field tests will continue, including in areas in which mosquito- borne disease is a severe health problem. This sterol auxotrophic fungus requires an exogenous source of sterols to enter its reproductive cycle. Precise structural requirements for bulk and regulatory roles of sterols will be determined. Phospholipids, including sphingolipids which regulate enzymic activity, are involved in the control of L. giganteum growth and morphogenesis. The effect of sterols on phospholipid uptake, synthesis and metabolism will be examined. Sterol regulation of eicosanoid and related oxygenated fatty acid metabolism will be investigated and correlated with specific developmental stages of the fungus. Eicosanoids are mediators of the inflammatory response in mammals. Use of this fungus as a model system will provide the background for increasing oospore yields for commercial fermentation production of L. giganteum, and for future investigations of lipid-mediated enzymic activity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI022993-05
Application #
3134781
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1986-07-01
Project End
1995-05-31
Budget Start
1992-06-01
Budget End
1993-05-31
Support Year
5
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Washington
Department
Type
Schools of Arts and Sciences
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Kerwin, J L; MacKichan, J K; Semon, M J et al. (1996) Sterol and steryl ester regulation of phospholipase A2 from the mosquito parasite Lagenidium giganteum. Lipids 31:1179-88
Kerwin, J L; Torvik, J J (1996) Identification of monohydroxy fatty acids by electrospray mass spectrometry and tandem mass spectrometry. Anal Biochem 237:56-64
Kerwin, J L; Wiens, A M; Ericsson, L H (1996) Identification of fatty acids by electrospray mass spectrometry and tandem mass spectrometry. J Mass Spectrom 31:184-92
Mackichan, J; Thomsen, L; Kerwin, J et al. (1995) Unsaturated fatty acids are the active molecules of a glucan-synthase-inhibitory fraction isolated from entomophthoralean protoplasts. Microbiology 141 ( Pt 10):2757-62
Woodring, J L; Kaya, H K; Kerwin, J L (1995) Lagenidium giganteum in Culex tarsalis larvae: production of infective propagules. J Invertebr Pathol 66:25-32
Kerwin, J L; Tuininga, A R; Wiens, A M et al. (1995) Isoprenoid-mediated changes in the glycerophospholipid molecular species of the sterol auxotrophic fungus Lagenidium giganteum. Microbiology 141 ( Pt 2):399-410
Kerwin, J L; Tuininga, A R; Ericsson, L H (1994) Identification of molecular species of glycerophospholipids and sphingomyelin using electrospray mass spectrometry. J Lipid Res 35:1102-14
Kerwin, J L; Dritz, D A; Washino, R K (1994) Pilot scale production and application in wildlife ponds of Lagenidium giganteum (Oomycetes: Lagenidiales). J Am Mosq Control Assoc 10:451-5
Kerwin, J L; Duddles, N D; Washino, R K (1991) Effects of exogenous phospholipids on lipid composition and sporulation by three strains of Lagenidium giganteum. J Invertebr Pathol 58:408-14
Kerwin, J L; Dritz, D A; Washino, R K (1990) Confirmation of the safety of Lagenidium giganteum (Oomycetes: Lagenidiales) to mammals. J Econ Entomol 83:374-6

Showing the most recent 10 out of 13 publications