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Coastal wetlands are ecosystems associated with intense carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) recycling, modulated by salinity and other environmental factors that influence the microbial community involved in greenhouse gases production and consumption. In this study, we evaluated the influence of environmental factors on GHG concentration and benthic microbial community composition in coastal wetlands along the coast of the semiarid region. Wetlands were situated in landscapes along a south-north gradient of higher aridity and lower anthropogenic impact. Our results indicate that wetlands have a latitudinal variability associated with higher organic matter content at the north, especially in summer, and higher nutrient concentration at the south, predominantly in winter. During our sampling, wetlands were characterized by positive CO2 µM and CH4 nM excess, and a shift of N2O nM excess from negative to positive values from the north to the south. Benthic microbial communities were taxonomically diverse with > 60 phyla, especially in low frequency taxa. Highly abundant bacterial phyla were classified into Gammaproteobacteria (Betaproteobacteria order), Alphaproteobacteria and Deltaproteobacteria, including key functional groups such as nitrifying and methanotrophic bacteria. Generalized additive model (GAM) indicated that conductivity accounted for the larger variability of CH4 and CO2, but the predictions of CH4 and CO2 concentration were improved when latitude and pH concentration were included. Nitrate and latitude were the best predictors to account for the changes in the dissolved N2O distribution. Structural equation modeling (SEM), illustrated how the environment significantly influences functional microbial groups (nitrifiers and methane oxidizers) and their resulting effect on GHG distribution. Our results highlight the combined role of salinity and substrates of key functional microbial groups with metabolisms associated with both carbon and nitrogen, influencing dissolved GHG and their potential exchange in natural and anthropogenically impacted coastal wetlands.

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Sulfate reducing prokaryotes (SRP) are a phylogenetically and physiologically diverse group of microorganisms that use sulfate as an electron acceptor. SRP have long been recognized as key players of the carbon and sulfur cycles, and more recently, they have been identified to play a relevant role as part of syntrophic and symbiotic relations and the human microbiome. Despite their environmental relevance, there is a poor understanding about the prevalence of prophages and CRISPR arrays and how their distribution and dynamic affect the ecological role of SRP. We addressed this question by analyzing the results of a comprehensive survey of prophages and CRISPR in a total of 91 genomes of SRP with several genotypic, phenotypic, and physiological traits, including genome size, cell volume, minimum doubling time, cell wall, and habitat, among others. Our analysis discovered 81 prophages in 51 strains, representing the 56% of the total evaluated strains. Prophages are non-uniformly distributed across the SRP phylogeny, where prophage-rich lineages belonged to Desulfovibrionaceae and Peptococcaceae. Furthermore, our study found 160 CRISPR arrays in 71 SRP, which is more abundant and widely spread than previously expected. Although there is no correlation between presence and abundance of prophages and CRISPR arrays at the strain level, our analysis showed that there is a directly proportional relation between cellular volumes and number of prophages per cell. This result suggests that there is an additional selective pressure for strains with smaller cells to get rid of foreign DNA, such as prophages, but not CRISPR, due to less availability of cellular resources. Analysis of the prophage genes encoding viral structural proteins reported that 44% of SRP prophages are classified as Myoviridae, and comparative analysis showed high level of homology, but not synteny, among prophages belonging to the Family Desulfovibrionaceae. We further recovered viral-like particles and structures that resemble outer membrane vesicles from D. vulgaris str. Hildenborough. The results of this study improved the current understanding of dynamic interactions between prophages and CRISPR with their hosts in both cultured and hitherto-uncultured SRP strains, and how their distribution affects the microbial community dynamics in several sulfidogenic natural and engineered environments.

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Extremophiles are organisms capable of adjust, survive or thrive in hostile habitats that were previously thought to be adverse or lethal for life. Chile gathers a wide range of extreme environments: salars, geothermal springs, and geysers located at Altiplano and Atacama Desert, salars and cold mountains in Central Chile, and ice fields, cold lakes and fjords, and geothermal sites in Patagonia and Antarctica. The aims of this review are to describe extremophiles that inhabit main extreme biotopes in Chile, and their molecular and physiological capabilities that may be advantageous for bioremediation processes. After briefly describing the main ecological niches of extremophiles along Chilean territory, this review is focused on the microbial diversity and composition of these biotopes microbiomes. Extremophiles have been isolated in diverse zones in Chile that possess extreme conditions such as Altiplano, Atacama Desert, Central Chile, Patagonia, and Antarctica. Interesting extremophiles from Chile with potential biotechnological applications include thermophiles (e.g., Methanofollis tationis from Tatio Geyser), acidophiles (e.g., Acidithiobacillus ferrooxidans, Leptospirillum ferriphilum from Atacama Desert and Central Chile copper ores), halophiles (e.g., Shewanella sp. Asc-3 from Altiplano, Streptomyces sp. HKF-8 from Patagonia), alkaliphiles (Exiguobacterium sp. SH31 from Altiplano), xerotolerant bacteria (S. atacamensis from Atacama Desert), UV- and Gamma-resistant bacteria (Deinococcus peraridilitoris from Atacama Desert) and psychrophiles (e.g., Pseudomonas putida ATH-43 from Antarctica). The molecular and physiological properties of diverse extremophiles from Chile and their application in bioremediation or waste treatments are further discussed. Interestingly, the remarkable adaptative capabilities of extremophiles convert them into an attractive source of catalysts for bioremediation and industrial processes.

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The production of lignocellulosic-derived biofuels is a highly promising source of alternative energy, but it has been constrained by the lack of a microbial platform capable to efficiently degrade this recalcitrant material and cope with by-products that can be toxic to cells. Species that naturally grow in environments where carbon is mainly available as lignin are promising for finding new ways of removing the lignin that protects cellulose for improved conversion of lignin to fuel precursors. Enterobacter lignolyticus SCF1 is a facultative anaerobic Gammaproteobacteria isolated from tropical rain forest soil collected in El Yunque forest, Puerto Rico under anoxic growth conditions with lignin as sole carbon source. Whole transcriptome analysis of SCF1 during E.lignolyticus SCF1 lignin degradation was conducted on cells grown in the presence (0.1%, w/w) and the absence of lignin, where samples were taken at three different times during growth, beginning of exponential phase, mid-exponential phase and beginning of stationary phase. Lignin-amended cultures achieved twice the cell biomass as unamended cultures over three days, and in this time degraded 60% of lignin. Transcripts in early exponential phase reflected this accelerated growth. A complement of laccases, aryl-alcohol dehydrogenases, and peroxidases were most up-regulated in lignin amended conditions in mid-exponential and early stationary phases compared to unamended growth. The association of hydrogen production by way of the formate hydrogenlyase complex with lignin degradation suggests a possible value added to lignin degradation in the future.

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Esta Investigación tiene como objeto principal el establecimiento de las patologías periodontales más frecuentes que presentan los pacientes adultos-jóvenes sin compromiso sistémico, como también identificar cada tipo de estas enfermedades. Esta investigación es de tipo diagnóstica descriptiva aplicada a una población de doscientas personas que asistieron a las unidades de salud El Zamorán, La Presita, San Carlos y Milagro de la Paz, durante el período de febrero a julio del2004, tomando como muestra ciento veinte y cuatro unidades de análisis. Las cuales se analizaron por medio de dos tipos de instrumentos que fueron la guía de observación y el cuestionario , se utilizó también una prueba estadística conocida como "ji" cuadrado, dando los resultados siguientes: Del total de la población evaluada se encontró que cuarenta y cinco personas presentan enfermedad gingival y setenta y nueve presentan enfermedad periodontal. De los signos evaluados para obtener la estadística anterior nos da como resultado que ciento veinte y cuatro personas presentaron placa bacteriana y encía eritematosa, noventa y cuatro presentaron encía edematosa y cálculo supragingival , ochenta y seis presentaron cálculo subgingival ,setenta y nueve presentaron hemorragia al sondeo y bolsas periodontales, la presencia de exudado purulento de treinta y tres, la movilidad dental se presentó en setenta y nueve pacientes en la cual diez y nueve presentaron movilidad grado I, movilidad grado II cuarenta y nueve, movilidad grado III once. La evaluación de los hábitos de higiene oral presenta que ciento veinte y cuatro pacientes no conocen una técnica de cepillado dental, catorce se cepilla una vez, diaria y ciento diez mas de dos veces, diez y siete usan hilo dental y ciento siete no lo usan. Tomando en cuenta el análisis de los resultados obtenidos se concluye que: - De la población en estudio a la cual se le aplicó los instrumentos, se observó una frecuencia de un 36.30% en enfermedad gingival y un 63.70% en la enfermedad periodontal que corresponden a un 100% de ciento veinte y cuatro pacientes que representa la muestra.

The main objective of this research is to establish the most frequent periodontal pathologies that young-adult patients present without systemic compromise, as well as to identify each type of these diseases. This research is of a descriptive diagnostic type applied to a population of two hundred people who attended the El Zamorán, La Presita, San Carlos and Milagro de la Paz health units, during the period from February to July 2004, taking as a sample one hundred and twenty-five four units of analysis. Which were analyzed by means of two types of instruments that were the observation guide and the questionnaire, a statistical test known as "chi" square was also used, giving the following results: Of the total population evaluated, it was found that forty-five five people have gum disease and seventy-nine have periodontal disease. Of the signs evaluated to obtain the above statistics, we find that one hundred and twenty-four people presented bacterial plaque and erythematous gingiva, ninety-four presented edematous gingiva and supragingival calculus, eighty-six presented subgingival calculus, and seventy-nine presented hemorrhage on probing. and periodontal pockets, the presence of purulent exudate of thirty-three, dental mobility was presented in seventy-nine patients in which nineteen had degree I mobility, forty-nine degree II mobility, and eleven degree III mobility. The evaluation of oral hygiene habits shows that one hundred twenty-four patients do not know a tooth brushing technique, fourteen brush once, daily and one hundred and ten more than two times, seventeen use dental floss and one hundred and seven do not use it . Taking into account the analysis of the results obtained, it is concluded that: - Of the population under study to which the instruments were applied, a frequency of 36.30% was observed in gingival disease and 63.70% in periodontal disease, corresponding to 100% of one hundred twenty-four patients represented by the sample.

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