A Trypanosoma cruzi strain from southern Mexico is more virulent for male mice in part by blocking the immune response.

INTRODUCTION: Chagas disease is a neglected disease in the American continent. The southern Mexican state of Chiapas has the highest incidence rate of Chagas disease in the country. The disease, mainly caused by Tripanosoma cruzi in Mexico, is more prevalent in males than in females but the scientific basis for the sex-related tropism is not completely understood. The objective of this study was to evaluate the pathogenicity of a T. cruzi strain in mice of both sexes and to assess certain elements of the immune response in the infected animals. METHODOLOGY: Triatomines bugs were searched at Los Mezcales, Chiapas, Mexico and T. cruzi was identified by PCR and sequencing. A T. cruzi strain was isolated from the feces of triatomines bugs. Mice were infected with the strain and the virulence of the T. cruzi strain as well as the immune response against the infection was compared in male versus female mice. RESULTS: T. dimidiata was identified in all dwellings. 42.9% of the bugs were infected with T. cruzi lineage TcI. Male mice exhibited higher parasitemia than females, and developed leukopenia and lower levels of anti-T. cruzi antibodies compared to female mice. CONCLUSIONS: The identification of the T. cruzi strain in this endemic region of Mexico revealed that male mice are prone to this infectious protozoo, in addition to manifesting a deficient immune response against infection. These findings may explain the greater number of cases of Chagas disease among men in this endemic region of Latin America.

Organización, mantenimiento y preservación de la Colección de Cultivos Bacterianos del Instituto de Ciencias Biológicas de la Universidad de Ciencias y Artes de Chiapas (UNICACH), México / Organization, maintenance, and preservation of the Bacterial Culture Collection of the Biological Sciences Institute, University of Science and Arts of Chiapas (UNICACH), Mexico

Los ceparios o colecciones de microorganismos son fuentes de recursos genéticos cuyo propósito es la preservación de la diversidad biológica, garantizando su disponibilidad para actividades de docencia, investigación y comerciales. En este trabajo se verificó la viabilidad, pureza y características biológicas de las bacterias que conforman el cepario del Instituto de Ciencias Biológicas de la Universidad de Ciencias y Artes de Chiapas, y se organizó y estructuró la información obtenida en un portal virtual, para propiciar la cooperación académica. El cepario cuenta con 33 microorganismos, la mayoría del género Streptococcus y Escherichia (45,1 y 21,2%, respectivamente). Del primer género, se confirmó la identificación de S. pyogenes (40%), exhibiendo la mayoría genes que codifican para DNAsas. Con respecto al segundo género, un 58,3% de las bacterias fueron confirmadas taxonómicamente como E. coli. De esta especie, la colección cuenta con las cepas prototipo causantes de diarrea y que han preservado sus rasgos genéticos por más de cinco años. Dicho acervo ha impulsado actividades de docencia e investigación, a nivel local e internacional. Es importante que los ceparios sean fuentes sustentables de recursos biológicos, para la adquisición y suministro de especies bacterianas, con la finalidad de fomentar la interacción con la comunidad académica.

Strain collections or bacterial culture collections are genetic resources whose purpose is the preservation of biological diversity, ensuring their availability for teaching, research and trade activities. In this work viability, purity and biological characteristics of bacteria from the bacterial collection of the Institute of Biological Sciences, University of Science and Arts of Chiapas were studied. Information was structured and organized in a virtual site, to promote academic cooperation. The strain bank includes 33 microorganisms, most of the genus Streptococcus and Escherichia (45.1 and 21.2%, respectively). For Streptococcus, the identification of S. pyogenes (40%) was confirmed, by determination of most DNAses encoding genes. For Escherichia 58.3% were taxonomically confirmed as E. coli. For this species, the collection includes typical strains that produce diarrhea and their genetic traits have been preserved for more than five years. This bacterial culture collection has stimulated teaching and research activities at local and international levels. Strain collections are important sources of biological material which can provide bacterial species, in order to encourage interaction with the academic community.