RESUMOOs sistemas de ressurgência possuem uma grande diversidade de microrganismos pelágicos e sua composição e atividade são determinadas por fatores como a temperatura e a concentração de nutrientes. A técnica de Electroforese em Gel por Gradiente Desnaturante (EGGD) foi utilizada para verificar a variabilidade genética espacial e temporal de Bacteria e Archea em duas estações na costa da região de Arraial do Cabo; uma com maior pressão da ressurgência, e a outra sobre pressão antropogênica. Além disso, as variáveis bióticas e abióticas foram medidas nas águas superficiais e de fundo de outras três estações situadas entre essas estações. Seis amostragens foram realizadas durante um ano e representaram adequadamente os diferentes graus de ressurgência e de pressões antropogênicas no sistema. A Análise por Componente Principal (ACP) mostrou uma correlação negativa entre a concentrações de amônia e de fósforo e a produção secundária procariótica e o total de bactérias heterotróficas. A ACP também mostrou uma correlação negativa entre a temperatura e a abundância de células procarióticas. As composições de Bacteria e Archaea foram variáveis, assim como as condições oceanográficas, e a ressurgência teve uma pressão regional enquanto a pressão antropogênica foi pontual. Sugerimos que as medidas de produção secundária procariótica esteve associada à atividade de ambas Bacteria e Archaea, e que a disponibilidade de substrato e a temperatura determinam a ciclagem de nutrientes.

ABSTRACTUpwelling systems contain a high diversity of pelagic microorganisms and their composition and activity are defined by factors like temperature and nutrient concentration. Denaturing gradient gel electrophoresis (DGGE) technique was used to verify the spatial and temporal genetic variability of Bacteria and Archaea in two stations of the Arraial do Cabo coastal region, one under upwelling pressure and another under anthropogenic pressure. In addition, biotic and abiotic variables were measured in surface and deep waters from three other stations between these stations. Six samplings were done during a year and adequately represented the degrees of upwelling and anthropogenic pressures to the system. Principal Component Analysis (PCA) showed negative correlations between the concentrations of ammonia and phosphorous with prokaryotic secondary production and the total heterotrophic bacteria. PCA also showed negative correlation between temperature and the abundance of prokaryotic cells. Bacterial and archaeal compositions were changeable as were the oceanographic conditions, and upwelling had a regional pressure while anthropogenic pressure was punctual. We suggest that the measurement of prokaryotic secondary production was associated with both Bacteria and Archaea activities, and that substrate availability and temperature determine nutrients cycling.

Duas amostras de bactérias psicrófilas foram isoladas do solo da Ilha do Rei Jorge, na Antártica. A análise filogenética baseada no gene do RNAr 16S (rrs) levou à correlação destes isolados com Sporosarcina aquimarina(99%) e Algoriphagus antarcticus(99%), com porcentagem de alinhamento de 99% e 98%, respectivamente. O sobrenadante do meio de cultura de ambos os isolados apresentou atividades proteolíticas detectadas por eletroforese em gel de poliacrilamida contendo dodecil sulfato de sódio e gelatina como substrato proteico. Sob estas condições, S. aquimarina apresentou uma protease de 55 kDa com melhor atividade em pH 7,0 e a 27°C. Também foi detectada uma única protease extracelular em A. antarcticus,no entanto com massa molecular em torno de 90 kDa e com melhor atividade em pH 9,0 e a 37°C. As proteases de ambos os isolados foram inibidas por 1,10-fenantrolina e EDTA, dois inibidores de metaloproteases. Este é o primeiro registro de detecção de proteases em ambas as espécies, e nossos resultados podem contribuir para ampliar o conhecimento básico de proteases provenientes do ambiente antártico e podem ajudar na prospecção de futuras aplicações biotecnológicas dessas enzimas.

Two psychrophilic bacterial samples were isolated from King George Island soil, in Antarctica. The phylogenetic analysis based on the 16S rRNA (rrs) gene led to the correlation with the closest related isolates as Sporosarcina aquimarina (99%) and Algoriphagus antarcticus(99%), with query coverage of 99% and 98%, respectively.The spent culture media from both isolates displayed proteolytic activities detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis containing gelatin as protein substrate. Under the employed conditions, S. aquimarina showed a 55 kDa protease with the best activity detected at pH 7.0 and at 27°C. A. antarcticusalso showed a single extracellular protease, however its molecular mass was around 90kDa and its best activity was detected at pH 9.0 and at 37°C. The proteases from both isolates were inhibited by 1,10-phenanthroline and EDTA, two metalloprotease inhibitors. This is the first record of protease detection in both species, and our results may contribute to broaden the basic knowledge of proteases from the Antarctica environment and may help prospecting future biotechnological applications of these enzymes.

A cellulolytic bacterial strain, designated P118, isolated from the gut of the tropical fish Parotocinclus maculicauda was identified as belonging to the genus Paenibacillus based on phenotypic and chemotaxonomic characteristics and the 16S rRNA gene sequence. The novel strain was Gram-positive, spore-forming and rod-shaped. Catalase but not oxidase was produced. Carboxymethylcellulose was hydrolyzed but starch or gelatin was not. Acetoin production was negative whereas nitrate reduction and urease production were positive. Many carbohydrates served as carbon sources for growth. MK-7 was the predominant isoprenoid quinone. Anteiso-C15:0 (38.73%) and C16:0 (20.85%) were the dominant cellular fatty acids. Strain P118 was closely related to Paenibacillus amylolyticus NRRL NRS-290, P. pabuli HSCC 492, P. tundrae Ab10b, P. xylanexedens B22a, and P. tylopili MK2 with 98.3-98.8% 16S rRNA gene sequence similarity. The results presented here suggest that strain P118 represents a novel species of the genus Paenibacillus and it is a potential strain for further studies concerning its role in the production of industrially important products from cellulosic biomass.