[Optimization of extracting solutions of antibacterial molecules from Cenchritis muricatus (Gastropoda: Littorinidae)].

Introduction: marine mollusks are natural reservoirs of molecules with therapeutic potential for the treatment of infectious diseases, at a time when many antibiotic-resistant strains are being described.

Objective: to compare three solutions: 30 % acetic acid, 50 % methanol and saline-acid (NaCl 0.6 mol/L, 1 % HCl) according to their capacities to extract molecules with antimicrobial activity from the marine mollusk Cenchritis muricawus.

[Distribution and ecological characteristics of freshwater snails of medical importance in Santiago de Cuba province].

Introduction: The ability of freshwater snails to serve as intermediary host of parasites responsible for some tropical diseases is well known.

Objective: A malacological study was carried out in the Santiago de Cuba province in order to determine the distribution of freshwater snails of medical importance and their relation with the main ecosystems.

Method: Nineteen sites were sampled in the province and the abundance of each of the species was compared to the type of habitat by means of the correspondence analysis.

Distribution and habitat preferences of the genus Biomphalaria (Gastropoda: Planorbidae) in Cuba.

A study was carried out to determine the distribution and habitat preferences of several species of the genus Biomphalaria. Samples were taken at 350 freshwater locations in Cuba. Three species of Biomphalaria (Biomphalaria havanensis, Biomphalaria helophila and Biomphalaria pallida) were recorded based on their distribution.

[Ecological studies on mollusk populations of medical and veterinary relevance existing in La Coca farm].

Introduction: ecological studies were carried out on mollusk populations of medical and veterinary importance with emphasis on Fasciola hepatica intermediary hosts species.

Objectives: to determine the relative abundance of populations and the possible use of some species as biological control agents against F. hepatica intermediary hosts.

[Freshwater malacofauna of medical importance located in Yaguajay municipality, Sancti Spíritus province].

Objective: the study carried out in Yaguajay, Sancti Spíritus province was aimed at identifying the mollusk species present in the freshwater ecocystems as well as their distribution and abundance in each reservoir.

Methods: two years--2005 and 2006--were analyzed through 2 samplings per years covering the rainy and the dry season; 20 reservoirs were sampled to determine the present freshwater mollusks. Data were processed by Excelxp and the statistical analysis used SPSS version 8 processor and 4 x 4 contingency tables.

[Ecology of river mollusks of medical and veterinary importance in 3 sites in La Habana province].

An ecological research study was carried out in freshwater mollusk populations of medical and veterinary importance, in order to determine the biotic and abiotic factors that affect their dynamics. It was observed that the principal abiotic factors influencing abundance of mollusks were total hardness, salinity, acidity, alkalinity and CO2 concentration. Both aquatic plants and specific relations among mollusk groups were the principal biotic factors that affected the molluskan fauna.