Characterization and Carbon Metabolism in Fungi Pathogenic to Triatoma infestans, a Chagas Disease Vector

JUAREZ M.P; CRESPO R; CALDERÓN FERNÁNDEZ G; LECUONA R; CAFFERATA L.F.R

JOURNAL OF INVERTEBRATE PATHOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2000 vol. 76 p. 198 - 207

0022-2011

The pathogenicity of Metarhizium anisopliae (Ma) and Beauveria bassiana (Bb) isolates against Triatoma infestans, the major vector of Chagas disease in Argentina is reported. A 100% mortality was achieved with mean lethal times varying from 5.8 (Ma6) to 7.7 (Bb10) or 11.1 days (Bb5). The fatty acid, hydrocarbon and total lipid pattern were compared for glucose-grown and alkane-grown Bb10 cultures. The alkane-grown cells showed a lipid pattern different to that of glucose-grown cells, with triacylglycerol as the major lipid fraction whereas sterols prevailed in the glucose-grown cells. A significant reduction in the relative amounts of linoleic acid diminished the unsaturated/saturated fatty acid ratio for alkane-grown cells; in addition, large amounts of heptacosanoic and eicosanoic acids were detected in the saturated fraction. The hydrocarbon profile of Bb10 showed a saturated chain length distribution, with a marked prevalence for straight chains, ranging from n-C18 to n-C 37 in the carbon squeleton, with n-C22 as the major component. Alkane-grown cells showed no qualitative changes in their hydrocarbon fraction, but a similar ratio for odd/even carbon chains. After 48 hr-incubation assays, [1-14C]acetate uptake was largely diminished following a period of alkane-growth induction. Glucose-grown cells readily incorporated 19% of the label into phospholipids, hydrocarbons, triacylglycerols and free fatty acids. Instead, incorporation was reduced to 5.3% for alkane-grown cells, accounting only for phospholipid synthesis.