[show abstract][hide abstract] ABSTRACT: Plasmodium development within Anopheles mosquitoes is a vulnerable step in the parasite transmission cycle, and targeting this step represents a promising strategy for malaria control. The thioester-containing complement-like protein TEP1 and two leucine-rich repeat (LRR) proteins, LRIM1 and APL1, have been identified as major mosquito factors that regulate parasite loads. Here, we show that LRIM1 and APL1 are required for binding of TEP1 to parasites. RNAi silencing of the LRR-encoding genes results in deposition of TEP1 on Anopheles tissues, thereby depleting TEP1 from circulation in the hemolymph and impeding its binding to Plasmodium. LRIM1 and APL1 not only stabilize circulating TEP1, they also stabilize each other prior to their interaction with TEP1. Our results indicate that three major antiparasitic factors in mosquitoes jointly function as a complement-like system in parasite killing, and they reveal a role for LRR proteins as complement control factors.
[show abstract][hide abstract] ABSTRACT: We used the cysteine proteinase B (cpb) gene family of the trypanosomatid genus Leishmania as a target to develop rapid, specific, and easy-to-use polymerase chain reaction (PCR) tests to discriminate Leishmania infantum, Leishmania donovani, Leishmania tropica, Leishmania aethiopica, and Leishmania major. Identification of all 5 Old World species and validation of intraspecies variability are features lacking in other species-specific PCRs. Amplicon analysis was done on agarose gels and was further simplified by using an oligochromatography dipstick to detect L. infantum and L. donovani products. Because the analytical sensitivity is lower than that of certain other species- and genus-specific PCRs, our assays are especially valuable for use on cultured isolates or directly on cryostabilates. As such, they can be implemented by research and health centers having access to culturing, DNA isolation, and PCR.
[show abstract][hide abstract] ABSTRACT: In recent years, new methods have been developed for the molecular typing of Leishmania that need to be extensively validated by studies of clinical isolates in a well defined epidemiological context. The present study is a contribution to this effort. Using PCR-RFLP of gp63 and cpb genes, we analysed 59 isolates of L. (L.) infantum obtained from different regions of Algeria and originating from different clinical forms, hosts and zymodemes. PCR-RFLP identified 15 different genotypes among the four zymodemes analysed, thereby demonstrating a higher discriminatory power than multilocus enzyme electrophoresis. We did not see any significant relationships between PCR-RFLP patterns and host origin. However, cpb polymorphism showed two interesting trends: a possible relationship with the cutaneous origin of the isolates and an association with a West-East cline. We verified the proof of evidence of the direct applicability of gp63 and cpb PCR-RFLP in blood samples from dogs. Further work is needed to compare the sensitivity of pattern detection with cpb and gp63 PCR-RFLP but our results pave the way to future multilocus PCR-RFLP studies of L. (L.) infantum populations.
Transactions of the Royal Society of Tropical Medicine and Hygiene 07/2008; 102(6):556-63. · 1.82 Impact Factor