Marcadores moleculares de tipo inserción en bacterias de las familias Moraxellaceae y Helicobacteraceae (phylum Proteobacteria) / Molecular markers of insertion type in bacterias of the Moraxellaceae and Helicobacteraceae (phylum Proteobacteria) families

Se efectuó un estudio con el empleo de la metodología de Gupta, en el Departamento de Biología y Geografía de la Universidad de Oriente en Santiago de Cuba, para determinar marcadores moleculares de tipo inserción en secuencias de las proteínas ADN polimerasa I y ADN polimerasa III (subunidad alfa), obtenidas de bases de datos internacionales y posteriormente alineadas con el programa ClustalX2. Las familias Moraxellaceae y Helicobacteraceae han sido ampliamente estudiadas, porque comprenden agentes patógenos causantes de numerosas enfermedades en humanos, pero pocas investigaciones han estado dirigidas a la identificación de las características moleculares que puedan distinguir a sus miembros de otros grupos de bacterias; de manera que los presentes resultados constituyen un aporte al conocimiento de la genética y la bioquímica de estas familias y proveen herramientas moleculares para la clasificación taxonómica y el diagnóstico de especies patógenas

A study with the use of Gupta methodology was carried out in the Biology and Geography Department of Oriente University in Santiago de Cuba, to determine molecular markers of insertion type in sequences of the DNA polimerase I proteins and DNA polimerase III (alpha subunity), obtained from international databases and later on aligned with the ClustalX2 program. The Moraxellaceae and Helicobacteraceae families have been broadly studied, because they comprise pathogen agents that cause numerous diseases in humans, but few investigations have been directed to the identification of the molecular characteristics that can distinguish their members from other groups of bacterias; so these results constitute a contribution to the knowledge of genetics and biochemistry of these families and provide molecular tools for the taxonomic classification and the diagnosis of pathogen species

A simplified method for reconstituting active E. coli DNA polymerase III

Genome duplication in E. coli is carried out by DNA polymerase III, an enzyme complex consisting of ten subunits. Investigations of the biochemical and structural properties of DNA polymerase III require the expression and purification of subunits including α, ge, θ, γ, δ', δ, and β separately followed by in vitro reconstitution of the pol III core and clamp loader. Here we propose a new method for expressing and purifying DNA polymerase III components by utilizing a protein co-expression strategy. Our results show that the subunits of the pol III core and those of the clamp loader can be coexpressed and purified based on inherent interactions between the subunits. The resulting pol III core, clamp loader and sliding clamp can be reconstituted effectively to perform DNA polymerization. Our strategy considerably simplifies the expression and purification of DNA polymerase III and provides a feasible and convenient method for exploring other multi-subunit systems.

Sequence analysis of housekeeping genes recA, dnaE, and mdh in different serogroups or biotypes of Vibrio cholerae isolated from China / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze sequences of the housekeeping genes including recA, dnaE, and mdh in different serogroups or different biotypes of Vibrio cholerae (VC) strains isolated from China.</p><p><b>METHODS AND RESULTS</b>recA, dnaE, and mdh genes of Vibrio cholerae were obtained by PCR, sequenced and analyzed. Forty-four variable bases were identified in the 500 bases of recA gene of 18 VC strains, and the mutation of only 3 variable bases could result in changes of 2 amino acids. In the 600 bases of dnaE genes of 18 strains, 32 variable bases were found and only 1 contributed to an amino acid change. In the 367 bases of mdh genes of 18 strains, only 1 variable base was identified whose mutation involved an amino acid convertion. Toxic EI Tor biotype (EVC) strains and toxic O139 serogroup strains were closely related. Non-toxic strains of different serogroups or types were lowly related. Non-toxic and toxic strains of different serogroups or types were lowly related.</p><p><b>CONCLUSION</b>Toxic EVC and toxic O139 serogroup strains isolated from different areas of China may evolve from a common original strain, and toxic O139 VC strains may come from toxic EVC strains.</p>