Cloning, auto-induction expression, and purification of rSpaA swine erysipelas antigen.

This work reports the cloning, expression, and purification of a 42-kDa fragment of the SpaA protein from Erysipelothrix rhusiopathiae, the main antigenic candidate for a subunit vaccine against swine erysipelas. The use of an auto-induction protocol to improve heterologous protein expression in recombinant Escherichia coli cultures was also investigated. The cellular growth pattern and metabolite formation were evaluated under different induction conditions.

The copper resistance operon copAB from Xanthomonas axonopodis pathovar citri: gene inactivation results in copper sensitivity.

Xanthomonas axonopodis pv. citri (Xac) causes citrus canker and the completion of the Xac genome sequence has opened up the possibility of investigating basic cellular mechanisms at the genomic level. Copper compounds have been extensively used in agriculture to control plant diseases.

Protein profile of Acidithiobacillus ferrooxidans strains exhibiting different levels of tolerance to metal sulfates.

Strains of Acidithiobacillus ferrooxidans exhibited differences in the inhibition of Fe2+ oxidation in the presence of 250 mM of cadmium, zinc, and manganese sulfates in respirometric assays. Strains LR and 135 were practically not inhibited, whereas strains SSP and V3 showed significant inhibition (30-70%). Analysis by SDS-PAGE of total proteins from cells grown in the absence of metal sulfates showed different profiles between the more tolerant strains (LR and 135) and the more susceptible ones (SSP and V3).

Teaching molecular biology to undergraduate biology students: An illustration of protein expression and purification*.

Practical classes on protein expression and purification were given to undergraduate biology students enrolled in the elective course "Introduction to Genetic Engineering." The heterologous expression of the green fluorescent protein (GFP)* of Aequorea victoria is an interesting system for didactic purposes because it can be viewed easily during experiments. The students were provided with basic information about the molecular features and applications of the GFP in molecular biology, the available heterologous expression systems, and the theoretical and experimental details of GFP expression in Escherichia coli and its purification.