RESUMO
Outer membrane proteins (OMPs) expressed by Vibrio tubiashii under different environmental growth conditions were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, N-terminal amino acid sequencing, and PCR analyses. Results showed the presence of a 38- to 40-kDa OmpU-like protein and ompU gene, a maltoporin-like protein, several novel OMPs, and a regulatory toxR homolog.
Assuntos
Proteínas da Membrana Bacteriana Externa , Proteínas de Bactérias , Proteínas de Ligação a DNA , Fatores de Transcrição , Vibrio/crescimento & desenvolvimento , Adesinas Bacterianas/química , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Sequência de Aminoácidos , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/isolamento & purificação , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Porinas/química , Porinas/genética , Porinas/metabolismo , Receptores Virais/química , Receptores Virais/genética , Receptores Virais/metabolismo , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/química , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Vibrio/classificação , Vibrio/genética , Vibrio/metabolismoRESUMO
The HIV-1 transcriptional regulatory protein Tat is a pleiotropic factor that represses expression of the human Mn-superoxide dismutase. Tat increases oxidative stress, as shown by decreased glutathione and NADPH levels. These redox changes enhance proliferation and apoptosis and alter the activity of zinc thiolate-containing proteins such as Sp1. Cells stably producing the Tat protein have an increased proliferation rate, which can be inhibited by pretreatment with the antioxidant mercaptopropionylglycine. Conversely, cells exposed to low concentrations of the oxidant paraquat are stimulated to divide. Intermediate and higher paraquat levels result in increased apoptosis or necrosis, respectively, suggesting that the physiological end point depends on the dose of oxidant used. Furthermore, treatment with the zinc chelator (N,N,N', N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) sensitizes HeLa-tat cells to apoptosis. In these cells, binding of the zinc-containing factor Sp1 to its DNA sequence is higher than in parental cells. Normal DNA binding is partially restored by pretreatment with a compound that mimics superoxide dismutase activity. Interestingly, Sp1-DNA interactions decrease more rapidly in the HeLa-tat cells after TPEN treatment. HeLa cell extracts incubated in the presence of purified Tat protein have increased Sp1 binding, consistent with the results observed in Tat-transfected cells. These results suggest that the Tat protein, via direct or indirect mechanisms, increases proliferation, sensitizes cells to apoptosis, and changes the conformation of Sp1, affecting its ability to bind to its cognate DNA sequence and to retain its zinc.
Assuntos
Apoptose , Quelantes/farmacologia , Produtos do Gene tat/fisiologia , HIV-1/genética , Fator de Transcrição Sp1/metabolismo , Zinco/metabolismo , Apoptose/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Produtos do Gene tat/genética , Células HeLa , Humanos , Oxirredução , Compostos de Sulfidrila/metabolismo , Superóxido Dismutase/farmacologia , Produtos do Gene tat do Vírus da Imunodeficiência HumanaRESUMO
Kaposi's sarcoma of the penis is an initial manifestation of AIDS and the practising urologist should be aware of this form of presentation. We report 2 young intravenous drug abusers with this tumor in the male genitourinary system. The clinical course is unfavorable; therefore prompt diagnosis and management, based on the early recognition of the lesion, must be achieved.
