Cell surface alterations induced by methylene blue and direct electric current in Escherichia coli.

Cell surface properties, including hydrophobicity, zeta potential, carbohydrate and fatty acid components, were altered on treatment of E. coli K12 with methylene blue (MB) and direct electric current (DC). The treatment of fimbriated E. coli cells with MB greatly increased the agglutination of yeast cells when compared to untreated bacteria. However, this increased agglutination was markedly reduced when the bacteria were treated with MB plus DC. These results suggest that MB modifies cell surface components in the absence of light and these alterations are more pronounced when cells are treated simultaneously with MB and DC.

Effect of estrogens on the adhesion of trichomonas vaginalis to epithelial cells in vitro

The feeding behavior of six triatomid species toward latex condoms filled with blood at 26 ñ 1 and 36 ñ 1 grade C observed for 4 h. The species studied were Triatoma infestans, Triatoma brasiliensis, Tritoma vitiiticeps, Triatoma pseudomaculata, Rhodnius and Panstrongylus, and 34 to 348 insects were studied in each group (average, 190). All the life stages of each species were used. Although most insects (80%, average for 6 species) preferred the warmer blood, 54% of the individuals of all species fed on blood kept at 26 grade C. For Triatoma pseudomaculata, a higher proportion of insects fed on blood at 26 grade C (92%) than on blood at 36 grade C (65%). These results suggest that bait containing insecticides which are effective through the digest tract may be useful in the control of these vectors even at room temperature

Scanning electron microscopy of the antennal sensilla in female Culicoides paraensis (Diptera: Ceratopogonidae)

We studied by sanning electron microscopy the number, types, structure and distribution of the antennal sensilla of the medical important ceratopogonid Culicoides paraensis (Goeldi). There are about 174 sense organs on the antenmal flagellum which are classified as sensilla chaetica; sharp-tipped and blunt-tipped (type I and II) sensilla trichodea; sensilla basiconica; sensilla coeloconica; sensilla ampullacea and styloconic-type sensilla. The role of antennal sensory organs are discussed regarding the host preference of the biting midges

Effect of metronidazole on the cell surface charge of Trichomonas vaginalis and Tritrichomonas foetus

1. The effect of metronidazole, a drug used in the treatment of trichomoniasis, on the surface chage of both Trichomonas vaginalis and Tritrichomonas foetus was analyzed by cell electrophoresis. 2. Incubation of the parasites under anaerobic conditions for 2 or 120 min in the presence of 2.0 microng/ml metronidazole, a concentration which inhibits cell growth by about 50%, led to a marked decrease in the net surface charge of the parasites. 3. The metronidazole analogue, 1-hydroxyethyl-2-methyl-1-4-inhibited protozoan growth but had no effect on met surface charge. 4. These observations indicate that, in addition to its effect on intracellular structure, cuch as hydrogenosomes, metronidazole alters the surface of trichomonads