Pseudomonas aeruginosa and Bacillus cereus Isolated from Brazilian Cerrado Soil Act as Phosphate-Solubilizing Bacteria.

The phosphate-solubilizing microorganism is essential for soil quality and plant development and can serve as an alternative to reduce such Brazilian needs for importing phosphate overseas. Here, we isolated and selected bacteria from Brazilian Cerrado soils capable of solubilize phosphate. We obtained 53 bacteria isolates, of which 23 could solubilize phosphate at a pH of 7.0, 17 could solubilize phosphate at a pH of 6.0, and 8 could solubilize at a pH of 5.5. Using 16S rRNA gene sequences, we identified nine bacteria species clustered in four groups: Bacillus sp., Pseudomonas sp., Priestia sp., and Klebsiella sp. Our results revealed that the UFT01 (P. aeruginosa) and UFT42 (B. cereus) isolates exhibited the best phosphate solubilization performance at all tested pH values. We further recorded higher levels of solubilization and phosphate availability six days after the soil inoculation with P. aeruginosa, and enzymatic analysis of the soil samples revealed that the P. aeruginosa-inoculated samples resulted in four-fold higher enzymatic activities when compared to non-inoculated soils. The B. cereus soil inoculation increased ß-glucosidase activities and resulted in reduced the activities of arylsulfatase. Altogether, our findings demonstrated that P. aeruginosa and B. cereus isolated from Cerrado soils showed high phosphate solubilization potential.

Cleaved caspase-3 expression in hypothalamic magnocellular neurons may affect vasopressin secretion during experimental polymicrobial sepsis.

We investigated whether the vasopressin (AVP) secretion deficiency observed during cecal ligation and puncture (CLP)-induced sepsis may be caused by apoptosis in hypothalamic magnocellular neurons. Plasma cytokines (TNF-α, IL-1ß and IL-6) and nitrate levels were increased during sepsis and plasma AVP levels were higher in the early phase returning to basal levels in the late phase. Concomitantly, expression of the apoptosis effector, cleaved caspase 3, was increased in magnocellular neurons, inferring that this increase in hypothalamic neurons may be caused by cytokines and elevated nitrate levels. This in turn could compromise AVP secretion in the late phase of sepsis.