Potential Correlation between Carboxylic Acid Metabolites in Biomphalaria alexandrina Snails after Exposure to Schistosoma mansoni Infection

Carboxylic acids play an important role in both aerobic and anaerobic metabolic pathways of both the snail and the parasite. Monitoring the effects of infection by schistosome on Biomphalaria alexandrina carboxylic acids metabolic profiles represents a promising additional source of information about the state of metabolic system. We separated and quantified pyruvic, fumaric, malic, oxalic, and acetic acids using ion-suppression reversed-phase high performance liquid chromatography (HPLC) to detect correlations between these acids in both hemolymph and digestive gland gonad complex (DGG's) samples in a total of 300 B. alexandrina snails (150 infected and 150 controls) at different stages of infection. The results showed that the majority of metabolite pairs did not show significant correlations. However, some high correlations were found between the studied acids within the control group but not in other groups. More striking was the existence of reversed correlations between the same acids at different stages of infection. Some possible explanations of the underlying mechanisms were discussed. Ultimately, however, further data are required for resolving the responsible regulatory events. These findings highlight the potential of metabolomics as a novel approach for fundamental investigations of host-pathogen interactions as well as disease surveillance and control.

Evaluation of oligochromatography dipstick as a simplified molecular diagnostic tool for the diagnosis of cutaneous leishmaniasis

The demonstration of Leishmania parasite by microscopic examination of samples taken from skin lesions is of low sensitivity and requires expert parasitologists. On the other hand, molecular methods to detect Leishinania parasites are considered specific and sensitive. However, detection of amplicons by the classical methods is complex, expensive and needs equipments and highly trained personnel. This raises the demand for a simplified method of amplification and product detection. To evaluate the diagnostic accuracy of PCR Leishmania Oligo C-test for diagnosis of cutaneous leishmaniasis. The diagnostic accuracy of the Leishniania Oligo C-test was estimated in 30 skin scraping samples from patients presented at El Quorea specialized hospital, Taif, KSA. On the basis of parasitological detection of amastigotes by direct microscopic examination of Geimsa stained smears from skin lesions, patients were classified into confirmed cutaneous Ieishmaniasis [group A] and negative cases [group B]. Twenty patients were proved positive for Leishmania amastigotes by microscopic examination of stained smears. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic efficacy of the Leishmania Oligo C-test were 90%, 90%, 95%, 82%, 90%, respectively. These results indicate that this simple molecular technique may be employed for rapid diagnosis of cutaneous leishmaniasis. The Leishmania Oligo C-test showed high specificity and sensitivity when compared to results obtained by microscopic examination of skin scraping samples. The assay is a promising tool for simplified molecular detection of Leishmania parasites

Carboxylic Acids as Biomarkers of Biomphalaria alexandrina Snails Infected with Schistosoma mansoni

Biomphalaria alexandrina snails play an indispensable role in transmission of schistosomiasis. Infection rates in field populations of snails are routinely determined by cercarial shedding neglecting prepatent snail infections, because of lack of a suitable method for diagnosis. The present study aimed at separation and quantification of oxalic, malic, acetic, pyruvic, and fumaric acids using ion-suppression reversed-phase high performance liquid chromatography (HPLC) to test the potentiality of these acids to be used as diagnostic and therapeutic biomarkers. The assay was done in both hemolymph and digestive gland-gonad complex (DGG) samples in a total of 300 B. alexandrina snails. All of the studied acids in both the hemolymph and tissue samples except for the fumaric acid in hemolymph appeared to be good diagnostic biomarkers as they provide not only a good discrimination between the infected snails from the control but also between the studied stages of infection from each other. The most sensitive discriminating acid was malic acid in hemolymph samples as it showed the highest F-ratio. Using the Z-score, malic acid was found to be a good potential therapeutic biomarker in the prepatency stage, oxalic acid and acetic acid in the stage of patency, and malic acid and acetic acid at 2 weeks after patency. Quantification of carboxylic acids, using HPLC strategy, was fast, easy, and accurate in prediction of infected and uninfected snails and possibly to detect the stage of infection. It seems also useful for detection of the most suitable acids to be used as drug targets.