Biomass and enzymatic activities of marine bacteria in the presence of multiple metals.

Marine environments are a repository for metals, and humans have enhanced this phenomenon over the years. Heavy metals are notoriously toxic due to their ability to biomagnify in the food chain and interact with cellular components. Nevertheless, some bacteria have physiological mechanisms that enable them to survive in impacted environments. This characteristic makes them important as biotechnological tools for environmental remediation. Thus, we isolated a bacterial consortium in Guanabara Bay (Brazil), a place with a long metal pollution history. To test the growth efficiency of this consortium in Cu-Zn-Pb-Ni-Cd medium, we measured the activity of key enzymes of microbial activity (esterases and dehydrogenase) under acidic (4.0) and neutral pH conditions, as well as the number of living cells, biopolymer production, and changes in microbial composition during metal exposure. Additionally, we calculated the predicted physiology based on microbial taxonomy. During the assay, a slight modification in bacterial composition was observed, with low abundance changes and little production of carbohydrates. Oceanobacillus chironomi, Halolactibacillus miurensis, and Alkaliphilus oremlandii were predominant in pH 7, despite O. chironomi and Tissierella creatinophila in pH 4, and T. creatinophila in Cu-Zn-Pb-Ni-Cd treatment. The metabolism represented by esterases and dehydrogenase enzymes suggested bacterial investment in esterases to capture nutrients and meet the energy demand in an environment with metal stress. Their metabolism potentially shifted to chemoheterotrophy and recycling nitrogenous compounds. Moreover, concomitantly, bacteria produced more lipids and proteins, suggesting extracellular polymeric substance production and growth in a metal-stressed environment. The isolated consortium showed promise for bioremediation of multimetal contamination and could be a valuable tool in future bioremediation programs.

Responses of antioxidant enzymes, photosynthetic pigments and carbohydrates in micropropagated Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) under ex vitro water deficit and after rehydration / Respostas de enzimas antioxidantes, pigmentos fotossintéticos e carboidratos em Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) micropropagadas, sob déficit hídrico ex vitro e após reidratação

In this study, the activities of antioxidant enzymes, photosynthetic pigments, proline and carbohydrate contents in Pitcairnia encholirioides under ex vitro conditions of water deficit were evaluated. Results show that plants under progressive water stress, previously in vitro cultured in media supplemented with 30 g L-1 sucrose and GA3, accumulated more proline and increased peroxidase (POD) activity and the contents of photosynthetic pigments and carbohydrates. For plants previously in vitro cultured with 15 g L-1 sucrose and NAA, no differences were found for proline content and there were reductions in activities of peroxidase (POD), catalase (CAT) and poliphenoloxidase (PPO), and in contents of carbohydrates, with progress of ex vitro water deficit. After rehydration, plants showed physiological recovery, with enzymatic activities and contents of metabolites similar to those found in the controls not submitted to dehydration, regardless of the previous in vitro culture conditions. These results show that micropropagated P. encholirioides has high tolerance to dehydration once in ex vitro conditions, which can ensure the survival of plants from tissue culture when transferred to its natural environment, emphasizing the importance of such biotechnology for the propagation of endangered species.

Neste estudo, foram avaliadas as atividades de enzimas antioxidantes, pigmentos fotossintéticos, conteúdo de prolina e carboidratos em Pitcairnia encholirioides sob déficit hídrico em condições ex vitro. Os resultados mostraram que as plantas sob estresse hídrico progressivo, previamente cultivadas in vitro em meio de cultura suplementado com 30 g L-1 de sacarose e GA3 acumularam mais prolina e aumentaram a atividade da peroxidase (POD) e os teores de pigmentos fotossintéticos e carboidratos. Para plantas previamente cultivadas in vitro com 15 g L-1 de sacarose e ANA, não foram encontradas diferenças nos conteúdos de prolina e houve reduções nas atividades da peroxidase (POD), catalase (CAT) e polifenoloxidase (PPO), e no conteúdo de carboidratos, com o progresso do déficit hídrico ex vitro. Após a reidratação, as plantas apresentaram recuperação fisiológica, com atividades enzimáticas e conteúdo de metabólitos semelhantes aos encontrados nos controles não sujeitos à desidratação, independentemente das condições de cultivo in vitro. Estes resultados mostram que P. encholirioides micropropagada tem alta tolerância à desidratação uma vez em condições ex vitro, o que pode garantir a sobrevivência de plantas provenientes da cultura de tecidos quando transferidas para seu ambiente natural, enfatizando a importância desta biotecnologia para a propagação de espécies ameaçadas.

Responses of antioxidant enzymes, photosynthetic pigments and carbohydrates in micropropagated Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) under ex vitro water deficit and after rehydration / Respostas de enzimas antioxidantes, pigmentos fotossintéticos e carboidratos em Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) micropropagadas, sob déficit hídrico ex vitro e após reidratação

Abstract In this study, the activities of antioxidant enzymes, photosynthetic pigments, proline and carbohydrate contents in Pitcairnia encholirioides under ex vitro conditions of water deficit were evaluated. Results show that plants under progressive water stress, previously in vitro cultured in media supplemented with 30 g L-1 sucrose and GA3, accumulated more proline and increased peroxidase (POD) activity and the contents of photosynthetic pigments and carbohydrates. For plants previously in vitro cultured with 15 g L-1 sucrose and NAA, no differences were found for proline content and there were reductions in activities of peroxidase (POD), catalase (CAT) and poliphenoloxidase (PPO), and in contents of carbohydrates, with progress of ex vitro water deficit. After rehydration, plants showed physiological recovery, with enzymatic activities and contents of metabolites similar to those found in the controls not submitted to dehydration, regardless of the previous in vitro culture conditions. These results show that micropropagated P. encholirioides has high tolerance to dehydration once in ex vitro conditions, which can ensure the survival of plants from tissue culture when transferred to its natural environment, emphasizing the importance of such biotechnology for the propagation of endangered species.

Resumo Neste estudo, foram avaliadas as atividades de enzimas antioxidantes, pigmentos fotossintéticos, conteúdo de prolina e carboidratos em Pitcairnia encholirioides sob déficit hídrico em condições ex vitro. Os resultados mostraram que as plantas sob estresse hídrico progressivo, previamente cultivadas in vitro em meio de cultura suplementado com 30 g L-1 de sacarose e GA3 acumularam mais prolina e aumentaram a atividade da peroxidase (POD) e os teores de pigmentos fotossintéticos e carboidratos. Para plantas previamente cultivadas in vitro com 15 g L-1 de sacarose e ANA, não foram encontradas diferenças nos conteúdos de prolina e houve reduções nas atividades da peroxidase (POD), catalase (CAT) e polifenoloxidase (PPO), e no conteúdo de carboidratos, com o progresso do déficit hídrico ex vitro. Após a reidratação, as plantas apresentaram recuperação fisiológica, com atividades enzimáticas e conteúdo de metabólitos semelhantes aos encontrados nos controles não sujeitos à desidratação, independentemente das condições de cultivo in vitro. Estes resultados mostram que P. encholirioides micropropagada tem alta tolerância à desidratação uma vez em condições ex vitro, o que pode garantir a sobrevivência de plantas provenientes da cultura de tecidos quando transferidas para seu ambiente natural, enfatizando a importância desta biotecnologia para a propagação de espécies ameaçadas.

Responses of antioxidant enzymes, photosynthetic pigments and carbohydrates in micropropagated Pitcairnia encholirioides L.B. Sm. (Bromeliaceae) under ex vitro water deficit and after rehydration.

In this study, the activities of antioxidant enzymes, photosynthetic pigments, proline and carbohydrate contents in Pitcairnia encholirioides under ex vitro conditions of water deficit were evaluated. Results show that plants under progressive water stress, previously in vitro cultured in media supplemented with 30 g L-1 sucrose and GA3, accumulated more proline and increased peroxidase (POD) activity and the contents of photosynthetic pigments and carbohydrates. For plants previously in vitro cultured with 15 g L-1 sucrose and NAA, no differences were found for proline content and there were reductions in activities of peroxidase (POD), catalase (CAT) and poliphenoloxidase (PPO), and in contents of carbohydrates, with progress of ex vitro water deficit. After rehydration, plants showed physiological recovery, with enzymatic activities and contents of metabolites similar to those found in the controls not submitted to dehydration, regardless of the previous in vitro culture conditions. These results show that micropropagated P. encholirioides has high tolerance to dehydration once in ex vitro conditions, which can ensure the survival of plants from tissue culture when transferred to its natural environment, emphasizing the importance of such biotechnology for the propagation of endangered species.

Effects of induced diabetes and the administration of aminoguanidine in the biomechanical retention of implants: a study in rats.

BACKGROUND AND OBJECTIVE: The present study aimed to assess the effects of induced diabetes and the administration of aminoguanidine in the biomechanical retention of implants in rats. MATERIAL AND METHODS: Thirty-six rats were randomly divided into six groups: group 1, healthy rats (no aminoguanidine); group 2 and group 3, healthy rats receiving 10 and 20 mg/kg of aminoguanidine daily, respectively; group 4, diabetic rats (no aminoguanidine); and group 5 and group 6, diabetic rats receiving 10 and 20 mg/kg of aminoguanidine daily, respectively. In each rat an implant was inserted in the femur. After 28 d of healing, the rats were killed. The implants were removed by applying a counter-torque, and the maximum force required for the rupture of the bone-implant interface was recorded using an analog torque meter. The data were evaluated using analysis of variance and the Student's t-test. RESULTS: In the healthy groups, no statistically significant difference could be observed in the average counter-torque values for implant removal, whereas in the diabetic groups, a daily dose of 20 mg/kg of aminoguanidine raised the counter-torque values to the values found in healthy rats. CONCLUSION: The administration of 20 mg/kg of aminoguanidine daily in diabetic rats raised the biomechanical retention of the implants to the level observed in the healthy rat group.