Diverse UV-B resistance of culturable bacterial community from high altitude wetland water

VERÓNICA FERNÁNDEZ ZENOFF; JUDITH HEREDIA; MARCELA FERRERO; FAUSTINO SIÑERIZ; MARÍA EUGENIA FARÍAS

CURRENT MICROBIOLOGY

Springer

Lugar: New York; Año: 2006 vol. 52 p. 359 - 362

0343-8651

Isolation of most ultraviolet B (UV-B)-resistant culturable bacteria that occur in the habitat of Laguna Azul, a high-altitude wetland [4554 m above sea level (asl)] from the Northwestern Argentinean Andes, was carried out by culture-based methods. Water from this environment was exposed to UV-B radiation under laboratory conditions during 36 h, at an irradiance of 4.94 W/m2. It was found that the  total number of bacteria in water samples decreased; however, most of the community survived longterm irradiation (312 nm) (53.3 kJ/m2). The percentage of bacteria belonging to dominant species did not  vary significantly, depending on the number of UV irradiation doses. The most resistant microbes in the culturable community were Gram-positive pigmented species (Bacillus megaterium [endospores and/or vegetative cells], Staphylococcus saprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments. 2. It was found that the total number of bacteria in water samples decreased; however, most of the community survived longterm irradiation (312 nm) (53.3 kJ/m2). The percentage of  bacteria belonging to dominant species did not vary significantly, depending on the number of UV irradiation doses. The most resistant microbes in the culturable community were Gram-positive pigmented species (Bacillus megaterium [endospores and/or vegetative cells], Staphylococcus saprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments. 2). The percentage of bacteria belonging to dominant species did not vary significantly, depending on the number of UV irradiation doses. The most resistant microbes in the culturable community were Gram-positive pigmented species (Bacillus megaterium [endospores and/or vegetative cells], Staphylococcus aprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments. Bacillus megaterium [endospores and/or vegetative cells], Staphylococcus saprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments.Staphylococcus saprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments. Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments.2. It was found that the total number of bacteria in water samples decreased; however, most of the community survived longterm irradiation (312 nm) (53.3 kJ/m2). The percentage of  bacteria belonging to dominant species did not vary significantly, depending on the number of UV irradiation doses. The most resistant microbes in the culturable community were Gram-positive pigmented species (Bacillus megaterium [endospores and/or vegetative cells], Staphylococcus saprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments. 2). The percentage of bacteria belonging to dominant species did not vary significantly, depending on the number of UV irradiation doses. The most resistant microbes in the culturable community were Gram-positive pigmented species (Bacillus megaterium [endospores and/or vegetative cells], Staphylococcus aprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments. Bacillus megaterium [endospores and/or vegetative cells], Staphylococcus saprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments.Staphylococcus saprophyticus, and Nocardia sp.). Only one Gram-negative bacterium could be cultivated (Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments. Acinetobacter johnsonii). Nocardia sp. that survived doses of 3201 kJ/m2 were the most resistant bacteria to UV-B treatment. This study is the first report on UV-B resistance of a microbial community isolated from high-altitude extreme environments, and proposes a method for direct isolation of UV-B-resistant bacteria from extreme irradiated environments.