Universidade Federal de Santa Maria

About: Universidade Federal de Santa Maria is a education organization based out in Santa Maria, Brazil. It is known for research contribution in the topics: Population & Context (language use). The organization has 21178 authors who have published 35632 publications receiving 371665 citations.

Atividade antibacteriana de extrato hidro-alcoólico de folhas de jambolão (Syzygium cumini (L.) Skells)

Abstract: The antimicrobial activity of medicinal plants has been searched in diverse species, as much in Brazil as in other countries. The aim of this study was to evaluate the existence of hydro-alcoholic extract jambolan leaves 10% (w/v) antibacterial effect. Seventeen Gram positive and Gram negative isolated bacterial were used. The antibacterial action was evaluated through the inoculation of Mueller Hinton agar plates, with a bacterial inoculate of 3x10 8 cell/ mL, with four paper discs, being the first of commercial antimicrobial and the others embedded with 25µL of the extract, saline or ethanol. The plates were incubated at 37°C for 24 hours, and their reading of inhibition hales diameter was done. The extract inhibited the growth of 100% of the tested bacteria; the Gram positive isolates had presented an average hale of 19.5mm, while of the Gram negative was of 18.8mm. There was not significant inhibition of growth in treatments with saline and ethanol. As verified in this study, the tested extract presents antibacterial activity against all the isolates, without sensitivity difference among Gram positive and Gram negative microorganisms.

Aminolevulinate dehydratase (δ-ALA-D) as marker protein of intoxication with metals and other pro-oxidant situations

Abstract: δ-ALA-D is a metalloenzyme that has 3 vicinal thiol/thiolate groups that coordinate with Zn(II). The proximity between the sulfhydryl groups renders δ-ALA-D extremely sensitive to oxidation by soft electrophiles, such as Pb(II), Hg(II), As(III) and organoseleno and organotellurium compounds. In fact, blood δ-ALA-D is a classical biomarker of lead exposure in humans. The inhibition of δ-ALA-D can increase the concentration of 5-aminolevulinate (δ-ALA), which is a pro-oxidant compound. δ-ALA can generate oxidative stress that can further increase δ-ALA-D inhibition. Recently, data have been obtained indicating that the δ-ALA-D could be a marker of oxidative stress in human pathologies. In summary, considering its high sensitivity to pro-oxidant situations, δ-ALA-D can be considered a universal marker of oxidative stress.

Phenol- and toluene-degrading microbial populations from an aquifer in which successful trichloroethene cometabolism occurred

Abstract: We characterized the bacterial populations that grew in a Moffett Field, Calif., aquifer following three sequential field tests of phenol- or toluene-driven cometabolism of trichloroethene (TCE). Reducing the toluene and phenol concentrations in most-probable-number (MPN) tubes from 50 to 5 ppm increased the population density measured for these degraders by 1.5 and 1 log units, respectively, suggesting that natural populations might be quite sensitive to these substrates. Phenol and toluene degraders were isolated from the terminal MPN dilution tubes; 63 genetically distinct strains were identified among the 273 phenol- and toluene-degrading isolates obtained. TCE was cometabolized by 60% of the genetically distinct strains. Most strains (57%) grew on both phenol and toluene, and 78% of these strains hybridized to the toluene ortho-monooxygenase (TOM) probe. None of the strains hybridized to probes from the four other toluene oxygenase pathways. Gram-positive strains comprised 30% of the collection; all of these grew on phenol, and 47% of them also grew on toluene, but none hybridized to the TOM probe. Among the gram-negative strains, 86% of those that grew on both toluene and phenol hybridized to the TOM probe, while only 5% of those that were TOM-positive grew on toluene alone. A larger proportion of TCE degraders was found among gram-negative than gram-positive strains and among organisms that grew on phenol than those that grew on toluene. Hybridization of strains to the TOM probe was somewhat predictive of their TCE-cometabolizing ability, especially for strains isolated on toluene, but there was also a significant number (20%) of strains that hybridized to the TOM probe but were poor TCE cooxidizers. No Moffett Field isolates were as effective as Burkholderia cepacia G4 in cooxidizing TCE. Most of the aquifer strains ranged from moderately effective to ineffective in TCE cooxidation. Such populations, however, apparently accounted for the successful phenol- and toluene-stimulated TCE removal that occurred during the field assessment of this remediation process. This suggests that naturally occurring communities of only moderate TCE-cooxidizing ability may support successful TCE bioremediation as long as the phenol or toluene present is not limiting. This activity, however, may not be sustainable for the long term, because TCE-inactive populations that consumed toluene at rates equal to that of the best TCE degraders were present and hence would be expected to eventually dominate the community.