Genetic variability of Brazilian strains of the Microcystis aeruginosa complex (Cyanobacteria/Cyanophyceae) using the phycocyanin intergenic spacer and flanking regions (cpcBA)

The genetic and morphological variability among 15 Brazilian strains of Microcystis aeruginosa (Kütz.) Kütz. collected from four locations was examined and compared with several reference strains of M. aeruginosa, M. viridis (A. Br.) Lemm. and M. wesenbergii (Kom.) Kom. in Kondr. Brazilian strains were classified by morphological features and by comparison of the nucleotide sequences of the cpcBA intergenic spacer and flanking regions. Our results indicate that Brazilian strains classified as M. aeruginosa are phylogenetically diverse compared with reference strains of M. aeruginosa and that the current taxonomy underestimates genetic diversity within M. aeruginosa. The data also demonstrate that morphological criteria alone are inadequate to characterize Microcystis species. Although colonial characters were shown to vary considerably in culture, some genetic lineages demonstrated consistent cellular diameter ranges, indicating that cell size has value as a taxonomic character. The detection of six M. aeruginosa genotypes in a single water body indicates that morphological approaches can also seriously underestimate the diversity of Microcystis bloom populations.

Efeito do extrato aquoso de folhas de guanandi (Calophyllum brasiliense Cambess) no controle do crescimento de Microcystis aeruginosa

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de compostos inorgânicos, herbicidas e extratos foliares no desenvolvimento de microcystis aeruginosa e produção de microcistina

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Microcystin-LR in Brazilian Aquaculture Production Systems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Monitoramento de fitoplâncton e microcistina no reservatório da UHE Americana

Este trabalho foi realizado na UHE Americana, pertencente à Companhia Paulista de Força e Luz, e faz parte de um projeto de pesquisa e desenvolvimento realizado em conjunto com a Faculdade de Ciências Agronômicas - UNESP, de Botucatu. As amostragens de água foram realizadas nos meses de fevereiro, abril, junho e outubro de 2004. As características analisadas foram: temperatura da água, pH, oxigênio dissolvido, condutividade, nitrogênio total, nitrito, nitrato, amônia, fósforo total, fosfato, fosfato inorgânico, juntamente com análise qualitativa e quantitativa da comunidade fitoplanctônica e a toxicidade. O reservatório apresentou valores elevados de fósforo total, variando de 18 a 509 µg L-1; fosfato, de 4 a 463 µg L-1; nitrogênio total, de 0,99 a 17,25 mg L-1; e nitrato, de 0,26 a 15,29 mg L-1. Para a comunidade fitoplanctônica foram encontrados 103 táxons em todo o período amostrado; a maior riqueza foi encontrada no ponto P06, e a maior pobreza de táxons, nos pontos localizadas no corpo central do reservatório (P02, P03, P04 e P05). A maior concentração de cianofícea ocorreu em abril de 2004: 5.375.175 ind. L-1. As espécies que apresentaram as maiores densidades foram Microcystis aeruginosa, Anabaena spiroides, Microcystis sp. e Pseudoanabaena mucicola; a maior densidade foi apresentada por Anabaena spiroides, com 4.178.084 ind. L-1. Nos meses de junho e outubro a classe Cryptophyceae teve uma grande contribuição para a densidade total. Apesar da grande densidade de cianobactérias, os valores de toxicidade ficaram abaixo do limite permitido pela Portaria nº 1.469.

Heat budgets, thermal structure and dissolved oxygen in Brazilian reservoirs

A comparison of the thermal regime and oxygen distribution patterns of some Brazilian reservoirs was made. A strong latitudinal dependence of surface temperature, annual mean and annual range was found. Except for Tucurui Reservoir, a reservoir of the Equatorial zone, the lowest surface temperature of the year in the other compared reservoirs was observed from June to August while the highest extended from October to February. The decreasing trend of annual mean temperatures and thermal ranges was due to the increasing seasonal variability of insolation with the latitude. A positive relationship between the increase on thermal surface-bottom differences and the depth of water column was found for reservoirs of similar latitudes. A long thermal stratification (around four months) was evidenced in the lacustrine zone of reservoirs with a residence time higher than 40 days. Low fluctuation (<2%) of the annual variability of heat contents was observed for the Tucurui Reservoir, while in das Garcas Reservoir a manmade lake located in the frontier between tropical and temperate regions, the annual coefficient of variation attained 13%. Concerning the heat budgets, the value for the Tucurui Reservoir was two times higher than in das Garcas Reservoir. Both the morphometric and climatological factors affected the heat contents of the two compared reservoirs. In deep eutrophic reservoirs, a significant reduction on the oxygen concentrations in the hypolimnetic zone was frequently observed. In some oligotrophic stratified reservoirs, a decrease on oxygen with depth occurred when the temperature of the hypolimnion was higher than 20 degrees C and caused a biochemical oxygen demand. In das Garcas Reservoir, the actual oxygen deficits ranged from 0.40 to 1.52 mg.O-2.cm(-2) and appear to be linked to oxygen consumption after the senescence of Microcystis aeruginosa populations in the spring. But, other factors such as the allochthonous loads of organic matter also had an important role on the oxygen balance of das Garcas Reservoir.

Phytoplankton composition, dominance and abundance as indicators of environmental compartmentalization in Jurumirim Reservoir (Paranapanema River), São Paulo, Brazil

Patterns in the spatial and temporal composition, dominance and abundance of the phytoplankton community of the Jurumirim Reservoir (Brazil) were studied during one year at ten different sampling stations. The main phytoplankton associations were characterized by diatoms and blue-green algae, in distinctive patterns of dominance. The main species were Microcystis aeruginosa Kuetz, Anabaena circinalis Rabenhorst, A. spiroides Kleb., A. solitaria Kleb., Aulacoseira cf. italica Grunow and A. granulata (Ehr.) Simon. A high growth of Aulacoseira was observed in the upstream zones of the reservoir in spring, at the beginning of the seasonal rainy period. This growth was a response to increased flow rates and input of fresh nutrients by the main feeder rivers. A high concentration of blue-green algae, especially Anabaena circinalis and A. spiroides, was observed in winter (dry season) in the lacustrine part of the reservoir, towards the dam. These algae benefitted from the longer water retention times and greater internal circulation of nutrients in the absence of a thermocline at this time of the year. Among the Cyanophyceae, there was an alternation between M. aeruginosa, more abundant in summer, and Anabaena, dominant in autumn and winter. A conspicuous growth of Anabaena occurred in a diverticle of the reservoir, sheltered from the main advective processes that predominate in the central channel. Higher phytoplankton diversity was associated with the contact zone between riverine and lacustrine systems.

Bioaccumulation of Microcystins In Lettuce

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos alelopáticos de microcistinas em rúcula (Eruca sativa Mill.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ação alelopática de saxitoxinas e microcistinas em cianobactérias e microalgas verdes em condições controladas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos do extrato bruto e da microcistina-LR em Lactuca sativa L. (Asteraceae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Pseudomonas aeruginosa LBI production as an integrated process using the wastes from sunflower-oil refining as a substrate

Pseudomonas aeruginosa LBI produced surface active rhamnolipids when cultivated on waste from the sunflower-oil process under different conditions. These biosurfactants, which reduce the superficial and interfacial tensions between fluids, offer advantages over their chemical counterparts, especially because of their ecological acceptability. These molecules can be used in fields as diverse as chemical, pharmaceutical and petrochemical industries. In this work, we present the effect of C/N ratio on growth and production yield. The best production yields (Y-P/S) were achieved for C/N ratios (in g/g) of 8/1 (0.22) and 6.4/1 (0.23). The product concentration was very satisfactory (7.3 g/L) at C/N ratio of 8/1, especially when considering that the substrate was basically composed of wastes that would otherwise constitute an environmental disposal problem. (c) 2007 Elsevier Ltd. All rights reserved.

Isolation of Pseudomonas aeruginosa strains from dental office environments and units in Barretos, state of São Paulo, Brazil, and analysis of their susceptibility to antimicrobial drugs

Uma ampla variedade de patógenos oportunistas tem sido detectadas nos tubos de alimentação de água dos equipos odontológicos, particularmente no biofilme formado na superfície do tubo. Entre os patógenos oportunistas encontrados nos tubos de água, Pseudomonas aeruginosa é reconhecida como uma das principais causadoras de infecções nosocomiais. Foram coletadas 160 amostras de água e 200 amostras de fomites em quarenta clinicas odontológicas na cidade de Barretos, São Paulo, Brasil, durante o período de Janeiro a Julho de 2005. Setenta e seis cepas de P. aeruginosa, isoladas a partir dos fomites (5 cepas) e das amostras de água (71 cepas), foram analisadas quanto à susceptibilidade à seis drogas antimicrobianas freqüentemente utilizadas para o tratamento de infecções provocadas por P. aeruginosa. As principais suscetibilidades observadas foram para a ciprofloxacina, seguida pelo meropenem. A necessidade de um mecanismo efetivo para reduzir a contaminação bacteriana dentro dos tubos de alimentação de água dos equipos odontológicos foi enfatizada, e o risco da exposição ocupacional e infecção cruzada na prática odontológica, em especial quando causada por patógenos oportunistas como a P. aeruginosa foi realçado.

Detection of SPM and IMP metallo-beta-lactamases in clinical specimens of Pseudomonas aeruginosa from a Brazilian public tertiary hospital

Phenotypic and genotypic SPM and IMP metallo-beta-lactamases (MBL) detection and also the determination of minimal inhibitory concentrations (MIC) to imipenem, meropenem and ceftazidime were evaluated in 47 multidrug-resistant Pseudomonas aeruginosa isolates from clinical specimens. Polymerase chain reaction detected 14 positive samples to either bla(SPM) or bla(IMP) genes, while the best phenotypic assay (ceftazidime substrate and mercaptopropionic acid inhibitor) detected 13 of these samples. Imipenem, meropenem and ceftazidime MICs were higher for MBL positive compared to MBL negative isolates. We describe here the SPM and IMP MBL findings in clinical specimens of P. aeruginosa from the University Hospital of Botucatu Medical School, São Paulo, Brazil, that reinforce local studies showing the high spreading of bla(SPM) and bla(IMP) genes among Brazilian clinical isolates.

Risk factors for recovery of Imipenem-or ceftazidime-resistant Pseudomonas aeruginosa among patients admitted to a teaching hospital in Brazil

background. The prevalence of resistance to imipenem and ceftazidime among Pseudomonas aeruginosa isolates is increasing worldwide.objective. Risk factors for nosocomial recovery ( defined as the finding of culture- positive isolates after hospital admission) of imipenemresistant P. aeruginosa ( IRPA) and ceftazidime- resistant P. aeruginosa ( CRPA) were determined.design. Two separate case- control studies were conducted. Control subjects were matched to case patients ( ratio, 2: 1) on the basis of admission to the same ward at the same time as the case patient. Variables investigated included demographic characteristics, comorbid conditions, and the classes of antimicrobials used.setting. The study was conducted in a 400- bed general teaching hospital in Campinas, Brazil that has 14,500 admissions per year. Case patients and control subjects were selected from persons who were admitted to the hospital during 1992 - 2002.results. IRPA and CRPA isolates were obtained from 108 and 55 patients, respectively. Statistically significant risk factors for acquisition of IRPA were previous admission to another hospital ( odds ratio [ OR], 4.21 [ 95% confidence interval {CI}, 1.40- 12.66];), hemodialysis Pp. 01 ( OR, 7.79 [ 95% CI, 1.59- 38.16];), and therapy with imipenem ( OR, 18.51 [ 95% CI, 6.30- 54.43];), amikacin ( OR, 3.22 Pp. 01 P !.001 [ 95% CI, 1.40- 7.41];), and/ or vancomycin ( OR, 2.48 [ 95% CI, 1.08- 5.64];). Risk factors for recovery of CRPA were Pp. 005 Pp. 03 previous admission to another hospital ( OR, 18.69 [ 95% CI, 2.00- 174.28];) and amikacin use ( OR, 3.69 [ 95% CI, 1.32- 10.35]; Pp. 01). Pp. 01conclusion. Our study suggests a definite role for several classes of antimicrobials as risk factors for recovery of IRPA but not for recovery of CRPA. Limiting the use of only imipenem and ceftazidime may not be a wise strategy to contain the spread of resistant P. aeruginosa strains.