Institute Clemente Estable

Montevideo, Uruguay

Institute Clemente Estable

Montevideo, Uruguay
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Marizcurrena J.J.,University of the Republic of Uruguay | Marizcurrena J.J.,Institute Clemente Estable | Marizcurrena J.J.,Biodosimetry Service Institute Clemente Estable | Morel M.A.,Institute Clemente Estable | And 6 more authors.
Extremophiles | Year: 2017

Ultraviolet (UV) light irradiation has serious consequences for cell survival, including DNA damage by formation of cyclobutane pyrimidine dimers (CPD) and pyrimidine (6,4) pyrimidone photoproducts. In general, the Nucleotide Excision Repair pathway repairs these lesions; however, all living forms, except placental mammals and some marsupials, produce a flavoprotein known as photolyase that directly reverses these lesions. The aim of this work was the isolation and identification of Antarctic UVC-resistant bacteria, and the search for novel photolyases. Two Antarctic water samples were UVC-irradiated (254 nm; 50–200 J m− 2) and 12 UVC-resistant bacteria were isolated and identified by 16S rDNA amplification/analysis as members of the genera Pseudomonas, Janthinobacterium, Flavobacterium, Hymenobacter and Sphingomonas. The UVC 50% lethal dose and the photo-repair ability of isolates were analyzed. The occurrence of photolyase coding sequences in Pseudomonas, Hymenobacter and Sphingomonas isolates were searched by PCR or by searching in the draft DNA genome. Results suggest that Pseudomonas and Hymenobacter isolates produce CDP-photolyases, and Sphingomonas produces two CPD-photolyases and a 6,4-photolyase. Results suggest that the Antarctic environment is an important source of genetic material for the identification of novel photolyase genes with potential biotechnological applications. © 2017 Springer Japan

Martinez-Rosales C.,Institute Clemente Estable | Martinez-Rosales C.,University of the Republic of Uruguay | Castro-Sowinski S.,Institute Clemente Estable | Castro-Sowinski S.,University of the Republic of Uruguay
Polar Research | Year: 2011

We report the isolation and identification of bacteria that produce extracellular cold-active proteases, obtained from water samples collected near the Uruguayan Antarctic Base on King George Island, South Shetlands. The bacteria belonged to the genera Pseudomonas (growth between 4 and 30 °C) and Flavobacterium (growth between 4 and 18 °C). In all cases, extracellular protease production was evident when reaching the stationary phase at 18 and 4 °C but was not detected at 30 °C. The zymogram revealed the secretion of one extracellular protease per isolate, each with different relative electrophoretic mobility. The extracellular proteases produced at 4 °C showed thermal activity and stability at 30 °C. Both activity and stability at a temperature higher that 10 °C have no physiological meaning because the isolates do not experience such temperatures in the Antarctic environment; however, the possible ecological value of cold-active and -stable extracellular proteases is discussed. © 2011 C. Martínez-Rosales and S. Castro-Sowinski.

Herrera L.M.,University of the Republic of Uruguay | Garcia-Lavina C.X.,University of the Republic of Uruguay | Marizcurrena J.J.,University of the Republic of Uruguay | Volonterio O.,University of the Republic of Uruguay | And 3 more authors.
Polar Biology | Year: 2016

The oligochaete Grania sp. is a common inhabitant of Artigas Beach at Maxwell Bay (King George Island, South Shetland Islands, Maritime Antarctica) that proliferate during the summer season and feed on debris of red and brown algae. This investigation was undertaken to test the hypothesis that Grania sp. has an enzyme-producing microbiota that may facilitate the worm’s nutrient uptake by processing or metabolizing macroalgae compounds. A culture-based approach was used to investigate the occurrence of microorganisms able to degrade proteins, lipids and polysaccharides. Thirty-four hydrolytic enzyme-producing microorganisms associated with these worms, including bacteria and yeasts, were isolated and identified by sequencing a partial fragment of the 16S and 26S rDNA genes, respectively. These microorganisms have the ability to produce extracellular proteases, esterases, amylases, cellulases and agarases. The microbial genera found during this work (Flavobacterium, Pseudomonas, Salinibacterium, Psychrobacter, Cystobasidium and Rhodotorula) have been previously described in association with red and brown Antarctic algae. Our results suggest that this microbiome has a digestive capability that may assist Grania sp. in metabolizing nutrients from algae, leading us to consider the possibility of a mutualistic relationship between them. The association between the worm Grania sp. and a cold-active hydrolyzing microbiota may contribute to the macroalgae decomposition and nutrient recycling in the Antarctic ecosystem. © 2016 Springer-Verlag Berlin Heidelberg

Rivera Megret F.,Institute Clemente Estable | Rivera Megret F.,University of the Republic of Uruguay | Tejera Correa D.,Institute Clemente Estable | Tejera Correa D.,University of the Republic of Uruguay | And 5 more authors.
Revista Cubana de Plantas Medicinales | Year: 2013

Introduction: Achyrocline satureioides is a plant which has been widely used in popular medicine and experimental studies confirm its antioxidant and anti-inflammatory effects, attributable to the presence of flavonoids, mainly quercetin. Objectives: to evaluate the neuroprotective effects of a chronic oral preadministration to rats with an Achyrocline satureioides decoction (2 %). Methods: for decoction, dried flowers of Achyrocline satureioides were used. The consumption of food and AS decoction/water of the rats was evaluated daily and weight gain weekly; quercetin content in the decoction and in the plasma of the rats was evaluated by high performance liquid chromatography. The cerebral damage was assessed with a tetrazolium salt (TTC) and a behavioral test was performed previously. Nissl staining and Fluoro-Jade histochemistry were used. Results: the pre-treatment with Achyrocline satureioides in all groups reverted the functional deficit and, during 21 days, the infarction volume also decreased significantly. Nissl staining showed a higher percentage of preserved neuronal population and the Fluoro-Jade showed a decreased of the neurons in degeneration. Conclusions: the quercetin levels in the decoction and plasma of rats could explain the preventive benefits of Achyrocline satureioides due to the antioxidant and antiinflammatory properties described for this flavonoid.

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