RESUMO
Although the use of medicinal plants or natural products has increased in recent decades all over the world, little information is available on their potential risk to health. Annona crassiflora Mart., a plant commonly known as araticum in Brazil, has been widely used in folk medicine for a long time since its seeds and leaves are often utilised in the treatment of cancer, snake bites, and venereal diseases, its fruits are consumed as tonic and astringent, and its bark powder has anti-fungal and anti-rheumatic properties. To evaluate the genotoxic and mutagenic properties induced by the ethanolic extract of araticum leaves, we performed the prophage λ induction (Inductest) and bacterial mutagenicity assays. We used Escherichia coli WP2s(λ) and RJF013 strains in the lysogenic induction test, whereas the mutagenic studies were carried out using Salmonella typhimurium histidine auxotroph strains TA97a, TA98, TA100, and TA102. Each experiment was performed three times in duplicate and included positive and negative controls. No statistically significant (p > 0.05) positive results were obtained for any of the strains tested, which suggests that the ethanolic extract of araticum leaves did not exhibit direct mechanisms of genotoxicity or mutagenicity that could be detected by the tests used in the present work.
Assuntos
Annona/química , Escherichia coli/efeitos dos fármacos , Testes de Mutagenicidade/métodos , Extratos Vegetais/toxicidade , Salmonella typhimurium/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/genética , Escherichia coli/genética , Prófagos/efeitos dos fármacos , Prófagos/genética , Resposta SOS em Genética/efeitos dos fármacos , Resposta SOS em Genética/genética , Salmonella typhimurium/genéticaRESUMO
Although the use of medicinal plants or natural products has increased in recent decades all over the world, little information is available on their potential risk to health. Annona crassiflora Mart., a plant commonly known as araticum in Brazil, has been widely used in folk medicine for a long time since its seeds and leaves are often utilised in the treatment of cancer, snake bites, and venereal diseases, its fruits are consumed as tonic and astringent, and its bark powder has anti-fungal and anti-rheumatic properties. To evaluate the genotoxic and mutagenic properties induced by the ethanolic extract of araticum leaves, we performed the prophage λ induction (Inductest) and bacterial mutagenicity assays. We used Escherichia coli WP2s(λ) and RJF013 strains in the lysogenic induction test, whereas the mutagenic studies were carried out using Salmonella typhimurium histidine auxotroph strains TA97a, TA98, TA100, and TA102. Each experiment was performed three times in duplicate and included positive and negative controls. No statistically significant (p > 0.05) positive results were obtained for any of the strains tested, which suggests that the ethanolic extract of araticum leaves did not exhibit direct mechanisms of genotoxicity or mutagenicity that could be detected by the tests used in the present work.
Embora o uso de plantas medicinais ou de produtos naturais venha aumentando nas últimas décadas no mundo todo, existem poucas informações acerca de seu risco potencial para a saúde. Annona crassiflora Mart., uma planta comumente conhecida como araticum no Brasil, tem tido amplo uso em medicina popular há muito tempo, uma vez que suas sementes e folhas são frequentemente empregadas no tratamento de câncer, picadas de cobras e doenças venéreas, seus frutos são consumidos como tônico e adstringente, e o pó da casca de seu tronco apresenta propriedades antifúngicas e antirreumáticas. Para avaliar as propriedades genotóxica e mutagênica induzidas pelo extrato etanólico das folhas de araticum, utilizaram-se os testes de indução do profago λ (Induteste) e de mutagenicidade bacteriana. Foram empregadas as linhagens WP2s(λ) e RJF013 de Escherichia coli no teste de indução lisogênica, enquanto os estudos sobre mutagenicidade foram conduzidos utilizando as linhagens auxotróficas para histidina TA97a, TA98, TA100 e TA102 de Salmonella typhimurium. Cada experimento foi executado três vezes em duplicata, incluindo controles positivo e negativo. Não foram obtidos resultados positivos estatisticamente significativos (p > 0,05) para quaisquer das linhagens testadas, o que sugere que o extrato etanólico das folhas de araticum não apresentou mecanismos diretos de genotoxicidade ou mutagenicidade que pudessem ser detectados pelos testes usados no presente estudo.
Assuntos
Annona/química , Escherichia coli/efeitos dos fármacos , Testes de Mutagenicidade/métodos , Extratos Vegetais/toxicidade , Salmonella typhimurium/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/genética , Escherichia coli/genética , Prófagos/efeitos dos fármacos , Prófagos/genética , Resposta SOS em Genética/efeitos dos fármacos , Resposta SOS em Genética/genética , Salmonella typhimurium/genéticaRESUMO
Eleven Bacillus isolates from the surface and subsurface waters of the Gulf of Mexico were examined for their capacity to sporulate and harbor prophages. Occurrence of sporulation in each isolate was assessed through decoyinine induction, and putative lysogens were identified by prophage induction by mitomycin C treatment. No obvious correlation between ability to sporulate and prophage induction was found. Four strains that contained inducible virus-like particles (VLPs) were shown to sporulate. Four strains did not produce spores upon induction by decoyinine but contained inducible VLPs. Two of the strains did not produce virus-like particles or sporulate significantly upon induction. Isolate B14905 had a high level of virus-like particle production and a high occurrence of sporulation and was further examined by genomic sequencing in an attempt to shed light on the relationship between sporulation and lysogeny. In silico analysis of the B14905 genome revealed four prophage-like regions, one of which was independently sequenced from a mitomycin C-induced lysate. Based on PCR and transmission electron microscopy (TEM) analysis of an induced phage lysate, one is a noninducible phage remnant, one may be a defective phage-like bacteriocin, and two were inducible prophages. One of the inducible phages contained four putative transcriptional regulators, one of which was a SinR-like regulator that may be involved in the regulation of host sporulation. Isolates that both possess the capacity to sporulate and contain temperate phage may be well adapted for survival in the oligotrophic ocean.
Assuntos
Fagos Bacilares/genética , Bacillus/fisiologia , Lisogenia , Água do Mar/microbiologia , Bacillus/genética , Bacillus/virologia , Fagos Bacilares/efeitos dos fármacos , Fagos Bacilares/fisiologia , Bacillus anthracis/efeitos dos fármacos , Bacillus anthracis/genética , Sequência de Bases , DNA Viral/genética , Genoma Bacteriano , Genoma Viral , Integrases/genética , Lisogenia/efeitos dos fármacos , Microscopia Eletrônica de Transmissão , Mitomicina/farmacologia , Dados de Sequência Molecular , Oceanos e Mares , Prófagos/efeitos dos fármacos , Prófagos/genética , Prófagos/fisiologia , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/genética , Proteínas Virais/genética , Ativação Viral/efeitos dos fármacos , Ativação Viral/genética , Ativação Viral/fisiologia , Integração Viral/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Replicação Viral/genéticaRESUMO
Most bacterial cells carry prophage genomes either integrated into the host DNA or present as repressed plasmids. Methods are described for the induction of prophages using Mitomycin C, and for the isolation of prophage-cured bacterial cell lines.