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.

We report for the first time the expression of multiple protease activities in the first instar larva (L1) of the flesh fly Oxysarcodexia thornax (Walker). Zymographic analysis of homogenates from freshly obtained L1 revealed a complex proteolytic profile ranging from 21.5 to 136 kDa. Although some activities were detected at pH 3.5 and 5.5, the optimum pH for most of the proteolytic activities was between pH 7.5 and 9.5. Seven of 10 proteases were completely inactivated by phenyl-methyl sulfonyl-fluoride, suggesting that main proteases expressed by L1 belong to serine proteases class. Complete inactivation of all enzymatic activities was obtained using N-p-Tosyl-L-phenylalanine chloromethyl ketone (100 µM), a specific inhibitor of chymotrypsin-like serine proteases.

A dinâmica da infecção de B. bovis no carrapato-vetor B. microplus foi estudada em condições laboratoriais na Universidade Federal Rural do Rio de Janeiro no Laboratório de Protozoologia. Para tanto, foram examinadas 100 fêmeas ingurgitadas que se desprenderam naturalmente do hospedeiro vertebrado, sendo que 84 fêmeas apresentaram-se infectadas com esporocinetos de B. bovis, com a seguinte distribuição: 39%, 33%, e 12% nos dias 3, 4 e 5 de incubação, respectivamente. Foram obtidas amostras de ovos provenientes das fêmeas positivas para B. bovis, 100% das amostras de ovos estavam infectadas, apresentado a seguinte distribuição: 46,4%, 34,5%, 16,7% e 2,4% nos dias 4, 5, 6 e 7 de incubação, respectivamente. As freqüências acumuladas, tanto de fêmeas infectadas (84%) quanto de ovos infectados (100%) mantiveram-se até o 17° dia de incubação. De acordo com as freqüências acumuladas e o aumento do grau de infecção, conclui-se que amostras coletadas a partir do 5° e 7° dia de incubação, são ideais para o diagnóstico de B. bovis, em hemolinfa e ovos, respectivamente.

The dynamics of B. bovis infections in the tick-vector B. microplus, was studied in laboratory conditions at Universidade Federal Rural do Rio de Janeiro in the Laboratory of Protozoology, Brazil.. To do it, 100 engorged females naturally droped from vertebrate host were examined. From this total 84 females showed infected with sporokinets of B. bovis, with the following distribution: 39%, 33% and 12% on days 3, 4 and 5 of incubation, respectivelly. Eggs samples were obtained from the positives ones to B. bovis females and 100% were infected, showed the follow distribution: 46.4%, 34.5%, 16.7% and 2.4% on days 4, 5, 6 and 7 of incubation, respectivelly. The accumulative frequencies, of infected females (84%) and infected eggs (100%), were kept until 17th days of incubation. According to the accumulatives frequencies and the increase of the degree of incubation, it was concluded that samples collect on days 5th to 7th of incubation, are the best for diagnosis of B. bovis in hemolymph and eggs, respectively.