Effect of the Aedes fluviatilis saliva on the development of Plasmodium gallinaceum infection in Gallus (gallus) domesticus

Effect of Aedes fluviatilis saliva on the development of Plasmodium gallinaceum experimental infection in Gallus (gallus) domesticus was studied in distinct aspects. Chickens subcutaneously infected with sporozoites in the presence of the mosquito salivary gland homogenates (SGH) showed higher levels of parasitaemia when compared to those ones that received only the sporozoites. However, the parasitaemia levels were lower among chickens previously immunized by SGH or non-infected mosquito bites compared to the controls, which did not receive saliva. High levels of anti-saliva antibodies were observed in those immunized chickens. Moreover, 53 and 102 kDa saliva proteins were recognized by sera from immunized chickens. After the sporozoite challenge, the chickens also showed significant levels of anti-sporozoite antibodies. However, the ability to generate anti-sporozoites antibodies was not correlated to the saliva immunization. Our results suggest that mosquito saliva components enhance P. gallinaceum parasite development in naive chickens. However, the prior exposure of chickens to salivary components controls the parasitemia levels in infected individuals.

Assessment of PCR in the detection of Leishmania spp in experimentally infected individual phlebotomine sandflies (Diptera: Psychodidae: Phlebotominae)

DNA amplification by the polymerase chain reaction (PCR) was applied in the investigation of the presence of Leishmania (Kinetoplastida: Trypanosomatidae) parasites in single phlebotomine sandflies. Three phlebotomine/parasite pairs were used: Lutzomyia longipalpis/Leishmania chagasi, Lutzomyia migonei/Leishmania amazonensis and Lutzomyia migonei/Leishmania braziliensis, all of them incriminated in the transmission of visceral or cutaneous leishmaniasis. DNA extraction was performed with whole insects, with no need of previous digestive tract dissection or pooling specimens. The presence of either mouse blood in the digestive tract of the sandflies or the digestive tract itself did not interfere in the PCR. Infection by as few as 10 Leishmania sp. per individual were sufficient for DNA amplification with genus-specific primers. Using primers for L. braziliensis and L. mexicana complexes, respectively, it was possible to discriminate between L. braziliensis and L. amazonensis in experimentally infected vectors (L. migonei)

Morphological changes induced by colchicine in neutrophilis interfere with the distribution of glycogen particles

A incubaçäo de neutrófilos na presença de colchicina induz a formaçäo de protuverâncias, onde usando-se a técnica do ácido periódico-tiossemicarbazida-proteinato de prata, uma concentraçäo de partículas caracterizada como glicogênio foi encontrada. Outras estruturas citoplasmáticas, tais como mitocôndrias e grânulos, näo estavam presentes nas protuberâncias. A microeletrônica de varredura revelou que a superfície das protuberâncias era mais lisa que a do restante do corpo celular

Structural observations on the attachment of promastigotes of Leishmania mexicana amazonensis to the surface of macrophages

Se analiza el proceso de interacción entre el parásito Leishmania mexicana amazonensis y los macrófagos, en experimentos en los cuales se emplea una alta relación parásito/macrófago, mediante el empleo de las microscopías de luz y electrónicas de barrido y transmisión. Los parásitos se adhieren al macrófago pero no son ingeridos por éste. la adherencia se realiza en los promastigotes vivos por el flagelo, pero cuando se emplean amastigotas o promastigotas fijados en glutaraldehido la adherencia se realiza sin orientación específica. la adherencia de los parásitos a la superficie del macrófago induce cambios en la organización estructural de periferia de éste pero no interfiere con la distribución de los sitios de unión de la concanavalina A. La incubación previa de los macrófagos en presencia de citocalasina B o ferritina cationizada no interfiere con la adherencia de los parásitos a la superficie del macrófago