Total protein composition of young and adult Biomphalaria alexandrina snails with different compatibilities to Schistosoma mansoni infection / Composición total de proteína en caracoles Biomphalaria alexandrina juveniles y adultos con distintas compatibilidades a la infección por Schistosoma mansoni

Abstract:Schistosomiasis remains a disease of major global public health concern since it is a chronic and debilitating illness. The widely distributed Schistosoma mansoni that causes intestinal schistosomiasis represents a great threat. Its world-wide distribution is permitted by the broad geographic range of the susceptible species of its intermediate host, Biomphalaria, which serves as an obligatory host for the larval stage, at which humans get infected. The objectives were to identify the proteins responsible for the snails' compatibility outcome through differentiation between the total proteins among Biomphalaria alexandrina snails at different ages. The work was conducted on snails that differ in age and genetic backgrounds. Four subgroups (F1) from the progeny of self-reproduced susceptible and resistant snails (F0) were studied. Infection rates of these subgroups (young susceptible, adult susceptible, young resistant and adult resistant) were 90 %, 75 %, 40 % and 0 %, respectively. Using Sodium Dodecyl Sulphate Polyacrylamide Gel electrophoresis (SDS-PAGE), differences in protein expression were evaluated between adult and young snails of different subgroups. Dice similarity coefficient was calculated to determine the percentage of band sharing among the experimental subgroups. The results showed that the combination of similarities between age and compatibility status of the snails, lead to the highest similarity coefficient, followed by the combination of similarities of both genetic origin and age, even though they differ in the compatibility status. On the other hand, the differences in the genetic background, age and compatibility status, lead to the least similarity index. It was also found that the genetic background in young snails plays a major role in the determination of their compatibility, while the internal defense system has the upper hand in determining the level of adult compatibility. In conclusion, the findings of the present work highlight the great impact of the snail age in concomitance with the genetics and the internal defense in the determination of B. alexandrina/S.mansoni compatibility. Future works are recommended, as further characterization of the shared protein bands among the studied subgroups is needed to clarify their role in host-parasite relationship. Rev. Biol. Trop. 64 (4): 1747-1757. Epub 2016 December 01.

Resumen:La esquistosomiasis es una enfermedad crónica y debilitante que constituye una problemática de salud pública a nivel mundial. Debido a que Schistosoma mansoni está ampliamente distribuida y a que es el causante de la esquistosomiasis intestinal representa una gran amenaza. Biomphalaria es el hospedero intermedio y obligatorio para el estado larval, presenta una amplia distribución geográfica e infecta al ser humano. El objetivo fue identificar las proteínas responsables del efecto de compatibilidad en caracoles Biomphalaria alexandrina de distintos estadios a través de la diferenciación del total de proteínas en ellos. La investigación se llevó a cabo con caracoles de diferentes edades y antecedentes genéticos. Se estudiaron cuatro subgrupos (F1) de la progenie de caracoles susceptibles y resistentes reproducidos asexualmente (F0). Las tasas de infección de estos subgrupos (juvenil susceptible, adulto susceptible, juvenil resistente, adulto resistente) fueron 90 %, 75 %, 40 % y 0 %, respectivamente. Con la electroforesis en gel de poliacrilamida en presencia de dodecilsulfato sódico (SDS-PAGE) se evaluaron las diferencias en la expresión proteica entre los caracoles juveniles y adultos de los distintos subgrupos. Se calculó el coeficiente de similitud de Dice para determinar el porcentaje de bandas compartidas entre los subgrupos experimentales. Los resultados mostraron que la combinación de similitudes entre la edad y el estado de compatibilidad de los caracoles genera el mayor coeficiente de similitud seguido por el de la combinación de similitudes tanto de la edad como del origen genético aunque varían en el estado de compatibilidad. Por otra parte, las diferencias en los antecedentes genéticos, la edad y el estado de compatibilidad generan el índice de similitud más bajo. También se encontró que el antecedente genético en caracoles juveniles es importante en la determinación de su compatibilidad, mientras que el sistema de defensa interno es el que determina el nivel de compatibilidad en adultos. En conclusión, los resultados de este trabajo resaltan la importancia de la edad del caracol en conjunto con la genética y la defensa interna para determinar la compatibilidad de B. alexandrina/S.mansoni. Se recomienda realizar futuros trabajos así como una mayor caracterización de las bandas proteicas compartidas entre los subgrupos estudiados para esclarecer su papel en la relación hospedero-parásito.

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.

Effects of schistosoma mansoni experimental infection on some inorganic elements in the snail host biomphalaria alexandrina

The alteration in the concentrations of metallic ion Pb, Zn, K, Na, Co. Fe, and Cu in the soft parts of the Biomphalaria alexandrina snails shedding Schistosoma mansoni cercariae was detected by flame atomic absorption spectrometry. Six elements Pb, Zn, K, Na, Co, and Cu were found to be present at significantly higher concentrations in cercariae-shedding snails compared with uninfected snails. The concentration of Fe ion showed non-significant decrease in the tissues of cercariae-shedding snails. Variation in the present results compared with related previous studies lead to the suggestion that the effect of trematode parasitism on fresh-water snails should not be considered universal and might be varies according to the trematode-snail combination, the organs or the tissues analyzed and the analytical method used

Estudo quantitativo de metais presentes na hemolinfa de Biomphalaria glabrata (Gastropoda), infectadas e não infectadas com Schistosoma mansoni / Quantitative study of metal present in the hemolymph of Biomphalaria glabrata (Gastropoda), infected and uninfected with Schistosoma mansoni

Inicialmente, desenvolveu-se um estudo para quantificar e comparar as concentrações de alguns metais presentes em duas amostras de hemolinfa do caramujo Biomphalaria glabrata (infectados e não-infectados com Schistosoma mansoni). A espectrometria de emissão óptica com fonte de plasma induzido (ICP-OES), foi utilizada para analisar os metais nas duas amostras. Os metais estudados foram: alumínio, cálcio, cádmio, cobalto, cromo, cobre, ferro, potássio, magnésio, manganês, chumbo e zinco. Os resultados mostram que, a princípio, os metais não são fatores determinantes no processo de defesa desses organismos contra este parasita, quando presente nos seus tecidos.

Effects of the desiccation on Biomphalaria tenagophila (Orbigny, 1835) (Mollusca) infected by Schistosoma mansoni Sambon, 1907

Specimens of Biomphalaria tenagophila exposed to miracidia of Schistosoma mansoni were submitted to different desiccation periods as follows: group I: 24 h after exposure, desiccated for 28 days; group II: after cercariae elimination, desiccated for 7 days; group III: 21 days after exposure, desiccated for 7 days; group IV: 14 days after exposure, desiccated for 14 days; group V: 7 days after exposure, desiccated for 21 days. From the obtained data it was verified that desiccation was not capable of interrupting the development of larvae of S. mansoni in mollusks. A delay in the development of S. mansoni larvae in groups I, III, IV and V was observed. A pause was verified in the development of S. mansoni larvae in groups II, III, IV and V. Some larvae, in groups I, III, IV and V, did not suffer as a result of desiccation and continued their development. Larvae in the cercariae stage were shown to be more sensitive to desiccation. It was possible to obtain clearing of mollusks infected by sporocysts II and cercariae using a period of 7 days of desiccation

Arylsulfatases in fresh water snails

The biodegradation of glycosaminoglycans [GAGS] was studied in an attempt to introduce more selectively into the control of the host snails for parasitic diseases. Characterization of sulfatase acting on GAGs from Biomphalaria alexandrina, Bulinus truncatus, Physa acuta and Lymnaea cailliaudi were carried out. Cell organelles were separated from B. alexandrina 7 weeks post infected with 10 S. mansoni miracidia and noninfected snails. Acid phosphatase [APase] and arylsulfatase [ARase] activation were found mainly in the lysosomal and cytosolic fractions. Their activity increased after infection with S. mansoni miracidia. The effect of pH, substrate concentration and inhibitors on the ARase activity were examined in the four snail species. The results point to the presence of more than one form of the ARase for the following observations: [a] The presence of pH optima at 5.0-5.6 and a shoulder between 6-7. [b] Plotting initial velocity versus substrate [p-nitrocatechol sulfate] concentration did not give the typical Michaelian behaviour [concave downward]. [c] The lysosomal enzyme is more sensitive to the known ARase inhibitors [sulfate, phosphate and cyanide]. Electrophoresis of the degradation products of chondroitin sulfate by the crude extract on agarose gel indicate that the extract contain sulfatase, beta-glucocuronidase and beta-N-acetylgalactosaminidase

Evaluation of chemical and physical-morphological factors as potencial determinants of Biomphalaria pfeifferi (Krauss, 1848) distribution

This study was carried out in five sites along a small perennial river system in south-central Tanzania, which had been identified as the focus for transmission of intestinal schistosomiasis in the area. Malacological surveys preceding the study showed a focal distribution of Biomphalaria pfeifferi, intermediate host snail of Schistosoma mansoni, the snail being present in three sites but absent from the other two sites. The objective of this study was to evaluate to what extent chemical and/or physical-morphological factors determine the distribution of B. pfeifferi between these five sites. It was found that none of the chemical constituents in the waters examined were outside the tolerance range of B. pfeifferi snails. Moreover, the composition of water from B. pfeifferi-free sites was not different from that in those sites where snails occurred. Furthermore, none of the physical-morphological constituents seemed likely to be determinant for the absence of B. pfeifferi. In view of these findings, and those of previous studies, it is concluded that the focal distribuition of B. pfeifferi cannot be associated with a single environmental factor and is rather the result of more complex interactions of habitat factors.