Search

Objectives: Unlike higher organisms such as domestic animals and cultivated plants, which display a robust reproductive isolation and limited dispersal ability, microbes exhibit an extremely promiscuous gene flow and can rapidly disperse across the planet by multiple ways. Thus, microbial plasmids, including synthetic replicons, containing antibiotic resistance genes are a serious risk to public health. In this short communication, we explored the presence of synthetic elements in alfalfa symbionts (Ensifer meliloti strains) from agricultural soils. Methods: A total of 148 E. meliloti isolates from alfalfa plants growing under field conditions were collected from January 2015 to June 2019. Antimicrobial susceptibility testing was performed under laboratory conditions. We identified five kanamycin-resistant E. meliloti strains (named K1-K5). Whole genome sequencing analysis and conjugations were used to identify and study the plasmids of K strains. Results: We found that the genomes of K strains contain ampicillin, kanamycin and tetracycline resistance genes, the reporter gene lacZ from Escherichia coli and multiple cloning sites. These sequences were found within

After gene duplication, paralogous genes evolve independently, and consequently, the new proteins encoded by these duplicated genes are exposed to changes in their subcellular location. Although there are increasing evidence that phylogenetically related proteins play different functions in different subcellular compartments, the number of evolutionary steps required for the emergence of a novel protein with a novel subcellular localization remains unclear. Regarding this intriguing topic, here we examine in depth our previous reports describing both intracellular and extracellular polyhydroxybutyrate polymerases (PhaC) in the Pseudomonadales group. The recapitulation of the intracellular-to-extracellular localization switch of PhaC in these strains shows a gradual evolution from a simple cytosolic PhaC form to a complex extracellular PhaC form specifically secreted via the type 1 secretion system. This gradual evolution includes several adaptive and pre-adaptive changes at the genomic, genetic and enzymatic levels, which are intimately related to the lifestyle of organisms during the evolution of protein localization. We conclude that the protein localization switch can be an extremely complex process in nature. Fil: Stritzler, Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina Fil: Berini, Carolina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Jozefkowicz, Cintia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina Fil: Soto, Gabriela Cynthia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina Fil: Ayub, Nicolás Daniel. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The plant plasma membrane (PM) expresses two types of aquaporins: PIP1 and PIP2. These PIP are characterized by: i- the faculty to reduce water permeation through the pore after cytosolic acidification as a consequence of gating process, ii- the ability to modulate membrane water permeability by co-expression of both types.We investigated if these functional characteristics of PIP can act together to give a new and relevant modulation response to acidification. To test our hypothesis we used PIP1 and PIP2 from different plant sources (Beta vulgaris roots and Fragaria x ananassa fruits). The experimental approach used was to perform a functional study of PIP by means of the heterologous expression system Xenopus oocytes and analyzed the oocyte PM water permeability coefficient (Pf) when PIP are injected.Briefly, the Pf was increased ten-fold by PIP2, but it remained low for both control oocytes and PIP1 injected ones. Moreover, when oocytes expressed PIP2, a partial (70%) pH inhibitory response under cytosolic acidification (pH 6) was detected.When PIP1-PIP2 co-expression was assayed, Pf was enhanced seven-fold in comparison with Pf obtained by PIP2 expression alone. Furthermore, the pH dependent behavior showed that PIP1-PIP2 co-expression accounts for different pH sensitivity by shifting the EC50 of the inhibitory response from pH 6.1 to pH 6.9, compared to PIP2.Our results show that: i- PIP co-expression impacts on the membrane water permeability not only by modulating the water transport capacity but also the pH regulatory response, improving in this way membrane plasticity, ii- this PIP behavior is not a tissue specific and/or species-dependent response but a more general one.In conclusion, aquaporin co-expression widens and enhances regulatory properties that control adjustment of water movements which might be of great importance to react to variable osmotic and pH stress.