(1S,3S,7R)-3-methyl-alpha-himachalene from the male sandfly Lutzomyia longipalpis (Diptera: Psychodidae) induces neurophysiological responses and attracts both males and females.

Lutzomyia longipalpis adult males form leks on or near hosts and release (1S,3S,7R)-3-methyl-alpha-himachalene from their tergal glands to lure females to the same site for mating and feeding. Here we have examined whether the male-produced attractant could also serve as a male aggregation stimulus. High resolution chiral capillary gas chromatography analysis of male tergal gland extracts, synthetic (1S,3S,7R)-3-methyl-alpha-himachalene, and a synthetic mixture of all isomers of 3-methyl-alpha-himachalene, was coupled to electrophysiological recordings from ascoid sensillum receptor cells in antennae of male and female sandflies. Receptor cells of both sexes responded only to the main component of the male tergal gland extract that eluted at the same retention time as (1S,3S,7R)-3-methyl-alpha-himachalene. Furthermore, of the eight 3-methyl-alpha-himachalene isomers in the synthetic mixture only the fraction containing (1S,3S,7R)-3-methyl-alpha-himachalene, co-eluting with an isomer of (1S*,3S*,7S*)-3-methyl-alpha-himachalene, elicited an electrophysiological response from male and female ascoid sensillum receptor cells. Both males and females flew upwind in a wind tunnel towards a filter paper disk treated with either 4-6 male equivalents of the tergal gland extract, pure (1S,3S,7R)-3-methyl-alpha-himachalene or the synthetic mixture of eight isomers. This indicates that (1S,3S,7R)-3-methyl-alpha-himachalene derived from L. longipalpis males may have a dual function in causing male aggregation as well as serving as a sex pheromone for females.

Biological effects of lithium chloride on Herpetomonas muscarum muscarum and Blastocrithidia culicis (kinetoplastida: trypanosomatidae).

Lithium is widely used in medicine as an antidepressive drug and for myelosuppression attenuation during chemotherapy. In spite of abundant literature, questions on the biological action of lithium ions are far from being answered. We have here examined the effects of lithium (10-200 mM) on culture forms of the trypanosomatid protozoa Herpetornonas muscarum muscarum and Blastocrithidia culicis. Incubation of these parasites with LiCl inhibited cell growth in a concentration-dependent manner, but growth could be restored when the drug was removed from the medium. Furthermore, Li+ induced cell differentiation in H. m. muscarum. Light microscopy examination of cell viability, using erythrosin B staining, showed that all treated parasites remained viable with all drug concentrations used. Ultrastructural analysis by transmission electron microscopy showed that the cells presented no signs of degeneration. However, in H. m. muscarum the nuclei lost their peripheral heterochromatin and appeared filled with a homogeneous matrix, whereas in B. culicis an increased amount of lipid droplets was present in the cytoplasm. Our data show that LiCl treatment arrested the cell division process, stimulated cell differentiation, and affected the metabolism of these parasites.