Effect of gamma irradiation on protease and nuclease enzymes activity and egg oviposition of Culex pipiens mosquito engorged with Hepatitis C Virus (HCV)

Abstract

Earlier investigations into the proteases indicated that protease in the mosquito is synthesized, and released into the gut lumen after the blood meal feeding. Likewise, the nuclease enzyme is stimulated if the blood meal contains a pathogen. To evaluate the effect of the Hepatitis C Virus (HCV) and gamma rays on egg oviposition, protease and nuclease enzymes secretion in the mid-gut of C. pipiens we designed four mosquito groups. The first group was fed on a sugar solution, the second was fed on blood meal, and both the third and fourth groups were fed infected blood meal with a viral load 1.3 × 106 IU/ml, and fourth group was also irradiated with the dose level 60 Gy. The results indicated that, there is a positive correlation between the blood meal feeding and mosquito reproductive potential. Fertility was significantly higher in the groups of mosquitoes given infected blood HCV virus. Otherwise, the reproductive potential of irradiated females that fed on the infected blood was drastically reduced. The value of protease activity in a sugar-fed mosquito is significantly low but there was a rapid increase in the enzyme activity post one day of blood meal feeding. After five days, the activity has decreased significantly but still above the residual value. Nuclease activity was very low post the sugar and blood meal feeding and there was no significant change (p ≤ 0.05) in the activity during the interval time. While, the infected HCV blood meal stimulated and increased the level of nuclease activity. Protease and nuclease activity in the irradiated mid-gut C. pipiens, that fed on infected HCV blood was lower than the non-irradiated insects. The reduction of protease and nuclease activity due to the influence of infected HCV blood meal and gamma irradiation, leads to a disorder of the immune system that protects the mosquito from the infection of a pathogen.