Diversity and phenotypic analyses of salt- and heat-tolerant wild bean Phaseolus filiformis rhizobia native of a sand beach in Baja California and description of Ensifer aridi sp. nov.

In northern Mexico, aridity, salinity and high temperatures limit areas that can be cultivated. To investigate the nature of nitrogen-fixing symbionts of Phaseolus filiformis, an adapted wild bean species native to this region, their phylogenies were inferred by MLSA. Most rhizobia recovered belong to the proposed new species Ensifer aridi.

Chromium Hyper-Tolerant sp. MH778713 Assists Phytoremediation of Heavy Metals by Mesquite Trees ().

Heavy metal accumulation in mesquite trees () growing in aluminum, titanium, chromium and zirconium-polluted soils of a semi-arid region in Mexico was investigated using wavelength dispersive X-ray fluorescence analysis. The results showed that trees can hyper accumulate up to 4100 mg/kg of Al, 14000 mg/kg of Fe, 1600 mg/kg of Ti, 2500 mg/kg of Zn, but not chromium, regarding high chromium concentrations found in soils (435 mg/kg). Since plant-associated microorganism can modulate phytoremediation efficiency, the biodiversity of associated bacteria was studied.

Post-transcriptional regulation of the alginate biosynthetic gene algD by the Gac/Rsm system in Azotobacter vinelandii.

Azotobacter vinelandii is a soil bacterium that produces the polysaccharide alginate. The two-component system GacS/GacA is required for alginate synthesis since a mutation in gacS or gacA significantly reduced the level of transcripts of algD, the gene encoding GDP-mannose dehydrogenase, a key enzyme of the alginate biosynthetic pathway. In many γ-proteobacteria, GacA homologs control the expression of small regulatory RNAs of the RsmZ/Y/X (CsrB/CsrC) family that interact with RsmA (CsrA) proteins.

[Histopathology of mucocutaneous leishmaniasis caused by Leishmania (Vianna) braziliensis].

A histopathological study of mucocutaneous leishmaniasis due to Leishmania (Viannia) braziliensis was carried out on 28 cutaneous and 114 mucosal biopsies, taken from Bolivian and Peruvian patients. This study showed similar histopathological findings in cutaneous and mucosal lesions. The cutaneous biopsies showed a strong epidermal hyperplasia occasionnally budding in the dermis.