ABSTRACT. Endophytic bacteria were isolated from stems of Eucalyptus spp (Eucalyptus citriodora, E. grandis, E. urophylla, E. camaldulensis, E. torelliana, E. pellita, and a hybrid of E. grandis and E. urophylla) cultivated at two sites; they were characterized by RAPD and amplified rDNA restriction analysis (ARDRA). Endophytic bacteria were more frequently isolated from E. grandis and E. pellita. The 76 isolates were identified by 16S rDNA sequencing as Erwinia/Pantoea (45%), Agrobacterium sp (21%), Curtobacterium sp (9%), Brevibacillus sp (8%), Pseudomonas sp (8%), Acinetobacter sp (4%), Burkholderia cepacia (2.6%), and Lactococcus lactis (2.6%). Genetic characterization of these endophytic bacteria isolates showed at least eight ARDRA haplotypes. The genetic diversity of 32 Erwinia/Pantoea and 16 Agrobacterium sp isolates was assessed with the RAPD technique. There was a high level of genetic polymorphism among all the isolates and there was positive correla- tion between the clusters and the geographic origin of the strains. These endophytic bacteria were further analyzed for in vitro interaction with endophytic fungi from Eucalyptus spp. We found that metabolites secreted by Erwinia/Pantoea and B. cepacia isolates had an inhibitory growth effect on some endophytic fungi, suggesting that these metabolites play a role in bacterial-fungal interactions inside the host plant. Apparently, these bacteria could have an important role in plant development; in the future they may be useful for biological control of diseases and plant growth promotion, as well as for the production of new metabolites and enzymes.

ABSTRACT.Few yeasts have shown the potential to efficiently utilize hemicellulosic hydrolyzate as the carbon source. In this study, microorganisms isolated from the Manaus region in Amazonas, Brazil, were characterized based on their utilization of the pentoses, xylose, and arabinose. The yeasts that showed a potential to assimilate these sugars were selected for the better utilization of lignocellulosic biomass. Two hundred and thirty seven colonies of unicellular microorganisms grown on hemicellulosic hydrolyzate, xylose, arabinose, and yeast nitrogen base selective medium were analyzed. Of these, 231 colonies were subjected to sugar assimilation tests. One hundred and twenty five of these were shown to utilize hydrolyzed hemicellulose, xylose, or arabinose as the carbon source for growth. The colonies that showed the best growth (N = 57) were selected, and their internal transcribed spacer-5.8S rDNA was sequenced. The sequenced strains formed four distinct groups in the phylogenetic tree, and showed a high percentage 11605-11612 (2015) of similarity with Meyerozyma caribbica, Meyerozyma guilliermondii, Trichosporon mycotoxinivorans, Trichosporon loubieri, Pichia kudriavzevii, Candida lignohabitans, and Candida ethanolica. The discovery of these xylose-fermenting yeasts could attract widespread interest, as these can be used in the cost-effective production of liquid fuel from lignocellulosic materials.

Staphylococcus spp. have become important human pathogens in recent decades due to the selection of resistant bacteria and the spread of their resistance genes in the environment. This study aimed to evaluate the resistance of Staphylococcus spp. obtained from sewage in the city of Manaus, Amazonas state, Brazil. The isolates were tested for susceptibility to antimicrobials using the Kirby-Bauer method for ampicillin, azithromycin, ciprofloxacin, clindamycin, chloramphenicol, erythromycin, gentamicin, oxacillin, cefoxitin, linezolid, penicillin, rifampicin, sulfazotrim, tetracycline and vancomycin. Among the strains isolated from sewage, the greatest resistance was observed for penicillin and oxacillin, with 100% of isolates resistant to these antibiotics. Some antibiotics had resistant and sensitive strains (ampicillin, clindamycin, erythromycin, cefoxitin, azithromycin). Staphylococcus spp. were identified as sensitive to ciprofloxacin chloramphenicol gentamicin linezolid sulfazotrim tetracycline, vancomycin, with no strain resistant to these antibiotics.

The study of microorganisms that inhabit the interior of plants (endophytes) has acquired great importance because of their potential to produce bioactive metabolites. Acmella ciliata (known in Brazil as jambu) is a native herb of South America, used in regional gastronomy and folk medicine in Amazonas -Brazil, has antibacterial properties, and may be a useful host for bioactive endophytes. We isolated endophytic microorganisms from A. ciliata and evaluated their ability to inhibit pathogenic fungi. We isolated 56 fungi and 39 endophytic bacteria, most of them from the leaves. The endophyte isolates were then tested in antagonism assays against the phytopathogens Fusarium decemcellulare and Colletotrichum gloeosporioides. The best antagonism index values against C. gloeosporioides were obtained with the endophytic fungus UEA-253 (40%), and the endophytic bacterium UEA-135 (46.3%). The highest antagonism index values were obtained against F. decemcellulare with the fungus UEA-234 (47.2%), and the bacterium UEA-135 (44.8%). The endophytic fungi with inhibitory bioactivity belong to the genera Curvularia, Colletotrichum, Plectosphaerella and Sordariomycetes, while the endophytic bacteria belong to the genera Bacillus, Pseudomonas and Enterobacter. We conclude that the endophytic fungi and bacteria isolated from A. ciliata have potential for use in the biocontrol of F. decemcellulare and C. gloeosporioides.

ABSTRACT. The herbicide propanil has long been used in rice production in southern Brazil. Bacteria isolated from contaminated soils in Massaranduba, Santa Catarina, Brazil, were found to be able to grow in the presence of propanil, using this compound as a carbon source. Thirty strains were identified as Pseudomonas (86.7%), Serratia (10.0%), and Acinetobacter (3.3%), based on phylogenetic analysis of 16S rDNA. Little genetic diversity was found within species, more than 95% homology, suggesting that there is selective pressure to metabolize propanil in the microbial community. Two strains of Pseudomonas (AF7 and AF1) were selected in bioreactor containing chemotactic growth medium, with the highest degradation activity of propanil exhibited by strain AF7, followed by AF1 (60 and 40%, respectively). These strains when encapsulated in alginate exhibited a high survival rate and were able to colonize the rice root surfaces. Inoculation with Pseudomonas strains AF7 and AF1 significantly improved the plant height of rice. Most of the Pseudomonas strains produced indoleacetic acid, soluble mineral phosphate, and fixed nitrogen. These bacterial strains could potentially be used for the bioremediation of propanil-contaminated soils and the promotion of plant growth.