Two serine proteases from Anopheles dirus haemocytes exhibit changes in transcript abundance after infection of an incompatible rodent malaria parasite, Plasmodium yoelii

Department of Pathobiology, The Third Military Medical University, Chongqing 400038, PR China.
Veterinary Parasitology (Impact Factor: 2.46). 06/2006; 139(1-3):93-101. DOI: 10.1016/j.vetpar.2006.02.017
Source: PubMed


Serine proteases are involved in regulation of innate immune responses, such as haemolymph coagulation, melanization reaction and antimicrobial peptide synthesis. Although several serine proteases have been characterized in Anopheles gambiae (A. gambiae), few were cloned from other malaria vectors. In this study, we identified three cDNA fragments of serine proteases (AdSp1, AdSp2 and AdSp3) from haemocytes of an oriental malaria vector, Anopheles dirus (A. dirus), by cloning of fragments amplified with degenerate primers into the T-vector. RT-PCR analysis demonstrated that both AdSp1 and AdSp3 genes were also expressed in salivary gland. Basic local alignment search tool (BLAST) search found that both AdSp1 and AdSp3 were highly similar in sequence to A. gambiae Sp14A and Sp14D2, insects prophenoloxidase activating enzyme (PPAE) and Drosophila protease easter. Semi-quantitative RT-PCR indicated the transcription level of both AdSp1 and AdSp3 in haemocytes of A. dirus infected with Plasmodium yoelii (P. yoelii) was significant higher than that fed on 5% glucose or normal mouse blood at 7 days after the infectious meal (p<0.05), when P. yoelii oocysts began to be melanized by A. dirus. Our results indicated that both AdSp1 and AdSp3 might play an important role during melanotic encapsulation of P. yoelii by A. dirus.

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Available from: Wenyue Xu, May 10, 2014
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    • "To be passed on to humans, the parasite requires successful completion of the sporogonic cycle in the midgut and the salivary glands of the mosquito (6). The female mosquito is responsible for blood digestion and is the first host for interaction with the parasite (7). Plasmodium must complete its development in the Anopheles mosquito before transmission to the new host (8, 9). "
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    • "To be passed on to humans, the parasite requires successful completion of the sporogonic cycle in the midgut and the salivary glands of the mosquito (Rodrigues et al., 2007). The female mosquito is responsible for digesting blood and is the first host for interaction with the parasite (Xu et al., 2006). Successful development of malaria parasites in mosquitoes involves complex transformations and spatial translocations within and between mosquito tissues. "
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    • "Changes in trypsin expression in response to immune challenge by pathogens are also observed in other insect vectors, including sand flies (Ramalho-Ortigao et al., 2003) and mosquitoes (Jahan et al., 1999; Xu et al., 2006). In sand flies, Ramalho et al. (Ramalho- Ortigao et al., 2003) observed a significant decrease in expression of the chymotrypsin Ppchym2, and a significant increase of the trypsin PpTryp1 in Leishmania major-infected midguts. "
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