Ultrastructural study on biomphalaria alexandrina haemocytes infected with schistosoma mansoni in Egypt and its correlation with nitric oxide level

Some snails of Biomphalaria alexandrina can resist the infection of Schistosoma mansoni so this study aimed to clearly this mechanism by using light and electron microscopy [EM] and determine the role of Nitric oxide in this mechanism. B. alexandrina snails used in this study were exposed individually to S. mansoni infection according to their response they were classified into susceptible group [shed cercariae] and resistant group [failed to shed cercariae]. Snails not exposed to infection were included in this study as control group. Nitric oxide [NO] level was assayed directly in the soluble fraction of B. alexandrina haemolymph supernatants collected from each group of B. alexandrina snails were subjected to NO assay by the Greiss reaction. The level of NO in haemolymph of infected snails was significantly increased [p<0.001] than both control and non infected snails groups, however, in non infected snails group had significantly [p<0.05] compared to control group. This study when correlated the changes recognized by EM with NO level the pro apoptotic effect of high level of NO on the haemocytes. Characterization and identification of cell shape of haemocytes in both haemolymph and tissue were examined by light and electron microscopy. Examination of B. alexandrina snail's haemocytes revealed three types of different cells classified according to their shape and granular contents. These cells are granulocytes, amoe-bocytes and hyalineocytes. Electron microscope Study also revealed the important role of granulocytes and amoebocytes as defense mechanism against snail infection. NO is considered an important anti parasite molecule; intra-molluscan stages of parasites switch off host NO defense response

Impact of cysteine protease inhibitor on infection of biomphalaria Alexandria with schistosoma mansoni and evaluation of protease activity in snail's haemolymph

This work aimed to study the effect of cysteine protease inhibitor on Schistosoma mansoni miracidia and their host Biomphalaria Alexandrina snails. The survival of miracidia decreased steadily with the increase in inhibitor concentration and the rising in their mortality was observed by increasing the inhibitor concentration up to 100 micro/ml. Exposure of snails to two concentrations of the cysteine protease inhibitor25 and 50 micro g/ml during miracidial exposure, reduced infection rate of the snails in the two groups 13.3% and 12.5%, respectively in comparison with its control group being 73.0%, Continuous exposure of the two concentrations of cysteine proteuse inhibitor in the two sizes [3 +/- 1mm] and [6 +/- 1mm], reduced infection rate being 3.03% and 5.5%, respectively. The control group of snails size 3 +/- 1mm was more susceptible to infection than that of the large ones [6 +/- mm], the infection rates was 73.0% and 15.6%, respectively. The protease activity in infected experimental groups increased significantly when compared to the un-infected control group [6.13 +/- 4.35] audit was also increased significantly in the one day tested group, compared to the other groups, in the majority of the infected groups

Immunolocalization of schistosoma mansoni and schistosoma haematobium antigens reacting with their Egyptian snail vectors

The reaction of the haemolymph and the tissue of infected intermediate hosts, Biomphalaria alexandrina and Bulinus truncatus to Schistosoma mansoni and S. haematobium antigens were investigated using the indirect immunoperoxidase technique. A new technique, Agarose cell block was used in collection of haemolymph which helped in collecting plenty of well formed cells in comparison to the ordinary one using the cytospin. Collected haemolymph and prepared tissues of uninfected and infected B. alexandria and B. truncatus were fixed and then reacted with anti-S. mansoni and anti-S. haematobium IgG polyclonal antibodies. The haemolymph and tissue of infected B. alexandrina and B. truncatus gave a positive peroxidase reaction represented by a brown colour. In haemolymph, the positive peroxidase reaction was detected mainly in the cytoplasm of the amoebocytes. In the tissue, it was detected in epithelial cells lining the tubules, male cells in the lumen of the tubules and in female oogonia cells along the periphery of the tubules. The similarity in the strength and distribution of positive reaction in B. alexandrina and B. truncates was observed as compared to control. Thus, the immunoperoxidase technique proved to be an effective indicator for the schistosome-antigen in the snails

Electrophoretic patterns of protein fractionations in hemolymph and tissues of Biomphalaria Alexandrina and bulinus truncatus during course of schistosome infection

Electrophoresis of plasma protein of B. alexandrina [uninfected and infected with S. mansoni] showed that the major dominant bands had molecular weights of 20,44,96,139 and 205KD in both types of snails. The 1day and 1 week post miracidia1 exposure [PME] groups were characterized by band 54 KD. All groups except a day PMA were characterized by a common band of MW 65 KD. Three days PME group had three bands of 123 KD, 150 and 177 KD, not found in other groups. The highest similarity index in 2 weeks PME and 5 weeks PME groups [during cercaria1 shedding] was 0.667 the lowest one was in 3-dys PME [0.5]. the 3-days PME had a unique band of MW 177.04 KD, not found in other groups. Similar electrophoretic pattern of B. alexandrina protein was seen. The major dominant bands had molecular weights of 14, 21, 80 and 140KD in both non-infected and infected snails. The 1day PME had a band of 48.483 KD, 3days PME had band of 87.985 KD, one-week PME group characterized by two band 61.761 KD and 70.33 KD. The two-weeks PME had a band 91.111 KD. While, the 5week PME [during cercaria1 production] was the only group that shared the common band of MW 115 KD with controls. The highest similarity index in 5 weeks PME [during cercaria1 shedding] group was 0.545 and the lowest one was in 1 week and 2 weeks PME [0.43]. The electrophoresis of plasma protein of B. truncates [uninfected and infected with S. haematobium] showed that the major dominant bands had molecular weights of 20, 30, 65, 80, 106, 117 and 170 KD in both type of snails. The 1 day PME group was characterized by three band of MWs 26.539, 51.891 and 91.509 KD. All experimental groups, except 5 weeks PME [during cercaria1 shedding] and control, had a common band of MW 45KD. Three days PME group had a characteristic band of 113.72 KD which was not found in any other group. The highest similarity index was in one week PME group was 0.857 and the lowest one in 1 days PME [0.5]. In B. truncatus tissue protein, the major dominant band by electro- phoretic pattern had molecular weights of 20, 45, 54, 80, 97, and 171KD in both type of snails. A day PME had of 73.544KD and a week PME had a band of MW 60.813 KD. Two and 5weeks PME groups had 2 bands of MWs 27 and 62 KD .All experimental groups had a characteristic band not found in control of MW 141 KD. The highest similarity index in 3-days PME was 0.8 and the lowest one was in 5 weeks PME during cercaria1 shedding [0.545].

Effect of double infection with schistosoma mansoni and echinostoma liei on some physiological parameters of BiomphalariaAlexandrina

The survival rate and fecundity of B. Alexandrina were greatly influenced when exposed to either S. mansoni or E. Liei miracidia. The snails exhibited much lower survival rate and fecundity when double exposed to both S. mansoni and E. liei miracidia than single exposure and control snails. The results indicated a disruption in the snail metabolism due to the exposure to S. Mansoni and E. Liei miracidia and this effect was more pronounced in case of double exposure to the two parasites. Protein concentrations in hemolymph and tissues were significantly reduced in all exposed snail groups than in the control group. A significant elevation in the levels of aspartate aminotransferase [ASAT] and alanine aminotransferase [Asat] enzymes was recorded in hemolymph and tissues of exposed snail than the unexposed control snails. The ASAT/ALAT ratios in tissue and hemolymph of single- exposed and unexposed B. Alexandrina did not exceed 1, while it increased up to 1.18 in hemolymph of double exposed snails. There were significant increases in the levels of acid and alkaline phosphatases enzymes in the exposed snails