Arthropods display different mechanisms to protect themselves against infections, among which antimicrobial peptides (AMPs) play an important role, acting directly against invader pathogens. We have detected several factors with inhibitory activity against Candida albicans and Micrococcus luteus on the surface and in homogenate of eggs of the tick Rhipicephalus (Boophilus) microplus. One of the anti-M. luteus factors of the egg homogenate was isolated to homogeneity. Analysis by electrospray mass spectrometry (ESI-MS) revealed that it corresponds to microplusin, an AMP previously isolated from the cell-free hemolymph of R. (B.) microplus. Reverse transcription (RT) quantitative polymerase chain reactions (qPCR) showed that the levels of microplusin mRNA gradually increase along ovary development, reaching an impressive highest value three days after the adult females have dropped from the calf and start oviposition. Interestingly, the level of microplusin mRNA is very low in recently laid eggs. An enhance of microplusin gene expression in eggs is observed only nine days after the onset of oviposition, achieving the highest level just before the larva hatching, when the level of expression decreases once again. Fluorescence microscopy analysis using an anti-microplusin serum revealed that microplusin is present among yolk granules of oocytes as well as in the connecting tube of ovaries. These results, together to our previous data, suggest that microplusin may be involved not only in protection of adult female hemocele, but also in protection of the female reproductive tract and embryos, what points this AMP as a considerable target for development of new methods to control R. (B.) microplus as well as the vector-borne pathogens.
Plasmodium berghei ANKA infection in CBA/J mice leads to the development of cerebral malaria (CM) that kills 80-90% of the animals in 6-9 days. This model has been used to study the pathogenesis of CM, which is a major cause of morbidity and mortality in Plasmodium falciparum-infected individuals. The role of cytokines in the induction of CM in the murine model has been well documented, but most studies have been restricted to the peak of neurological manifestations. Here we used a sequential approach to compare mice that developed CM with those that developed no cerebral pathology. Animals were examined for systemic histopathological changes and plasma Tumor Necrosis Factor-alpha (TNF) levels. The objectives were (a) to further determine the importance of factors commonly associated with murine CM-such as elevated levels of TNF and the presence of hemorrhage and vascular plugging-by comparing mice at different stages of infection and/or with different outcomes following infection and (b) to examine the importance of systemic changes-course of parasitemia and histopathological alterations in brain, liver, and lungs-in the development of CM. The data suggest that (a) the clinical manifestation of CM appears to be associated with a wave of merozoite release on days 6-7, (b) murine CM does not present reliable histopathological indicators, (c) there is no topographic association between the occurrence of intravascular plugging and the hemorrhagic foci, (d) monocyte-monocyte and monocyte-endothelial cell adherence were the most expressive histopathological events and were not restricted to brain vessels, (e) blood levels of TNF are not indicative of the local tissue reaction, (f) adhesiveness of monocyte/endothelial cells fluctuate during infection and is dissociated from the lymphocyte homing to the liver, and (g) pulmonary megakaryocytosis (megakaryopoiesis?) is a late event in the lungs.
Malnutrition hampers the course of schistosomiasis mansoni infection just as normal growth of adultKey words: Schistosoma mansoni -undernutrition -confocal scanning laser microscopy Schistosomiasis is a very widespread disease in the developing world and is one of the most important helminth infections. Malnutrition and schistosomiasis mansoni are both serious publichealth problems in Northeast Brazil and often overlap in the same geographical area (Coutinho et al. 1997a). Meanwhile, the role played by the nutritional status of the host on the development of schistosomiasis and vice versa is not clearly understood (Ferreira & Coutinho 1999
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