ABSTRACT
OBJECTIVE: To explore the possible defensive immunity of Culex pipiens quinquefasciatus larvae after being infected by Lagenidium giganteum. METHODS: To count and analyze morphologically hemocytes of the mosquito larvae with Giemsa's stain and by both phase contrast microscope and ordinary microscope. RESULTS: 1. Following the prolonged duration of infection, the number of hemocytes featured as increase, intense increase and gradual decrease. 2. 48 and 72 h after infection the proportion of plasmatocytes and granulocytes increased significantly, but that of prohemocytes showed a relatively slow increase, while 96 and 120 h after infection the proportion of spherulocytes and oenocytoids increased gradually and that of plasmatocyte and granulocytes showed a slow decrease. 3. After L. giganteum infection, vacuolation and morpholysis were found in plasmatocytes. CONCLUSION: The changes of hemocytes in amount, classification and morphology after infection revealed that Lagenidium giganteum can induce some defensive immune reactions in the larvae of Culex pipiens quinquefasciatus possibly due to a release of antigens or toxic substances by the fungus.
Subject(s)
Culex/immunology , Hemocytes/immunology , Oomycetes/pathogenicity , Animals , Blood Cell Count , Culex/microbiology , Larva/immunology , Larva/microbiologyABSTRACT
OBJECTIVE: To investigate the possible mechanism underlying the killing of Culex quinquefasciatus larvae by Lagenidium giganteum from the biochemical point of view. METHODS: The activities of alkaline phosphatase(AKP), acid phosphatase(ACP) and esterase(EST) were observed by using calcium-cobalt method, lead nitrate method and naphthol method. Results were photomicrographed and analysed quantitatively by image analysis using computer. RESULTS: The activities of AKP and ACP were decreased while the activities of EST were increased among the infected groups with different infection intensities. CONCLUSIONS: The changes of these enzyme activities might be one of the important mechanisms of action of Lagenidium giganteum against Culex quinquefasciafus larvae.
Subject(s)
Chytridiomycota/physiology , Culex/enzymology , Acid Phosphatase/metabolism , Alkaline Phosphatase/metabolism , Animals , Culex/microbiology , Esterases/metabolism , Larva/enzymology , Larva/microbiologyABSTRACT
Using immunohistochemical method, the antigens were shown to be mainly located in the cecum, tegument, esophagus, pharynx, excretory bladder, uterus and oral sucker of Pagumogonimus skrjabini. Histochemical analyses showed that antigens contained enzymes such as acid phosphatase (ACP), alkaline phosphatase (AKP), and acetylcholinesterase (AChE). Other chemical substances, for example, alkaline protein, basic protein, glycogen and acid mucopolysaccharides were also detected in the antigens of P. skrjabini.
