Diverse type I and type II methanotrophs cultivated from an Indian freshwater wetland habitat

Wetlands are the main natural sources of methane emissions, which make up a significant portion of greenhouse gas emissions. Such wetland patches serve as rich habitats for aerobic methanotrophs. Limited knowledge of methanotrophs from tropical wetlands widens the scope of study from these habitats. In the present study, a freshwater wetland in a tropical region in India was sampled and serially diluted to obtain methanotrophs in culture. This was followed by the isolation of methanotrophs on agarose-containing plates, incubated under methane: air atmosphere. Methanotrophs are difficult to cultivate, and very few cultures of methanotrophs are available from tropical wetlands. Our current study reports the cultivation of a diverse community of methanotrophs from six genera, namely, Methylomonas, Methylococcus, Methylomagnum, Methylocucumis (type I methanotrophs) along with Methylocystis, Methylosinus (type II methanotrophs). A high abundance of methanotrophs (106–1010 methanotrophs/g fresh weight) was observed in the samples. A Methylococcus strain could represent a putative novel species that was also isolated. Cultures of Methylomagnum and Methylocucumis, two newly described type I methanotrophs exclusively found in rice fields, were obtained. A large number of Methylomonas koyamae strains were cultured. Our study is pioneering in the documentation of culturable methanotrophs from a typical tropical wetland patch. The isolated methanotrophs can act as models for studying methanotroph-based methane mitigation from wetland habitats and can be used for various mitigation and valorization applications. (AU)

Epidemiología de la leptospirosis en los humedales del sur de España / Epidemiology of leptospirosis in the wetlands of Southern Spain

Objetivo: Conocer si la incidencia de leptospirosis en los capturadores de cangrejo rojo durante el periodo de captura es superior a la de la población general, así como identificar factores de riesgo y estimar los costes sanitarios directos e indirectos asociados a los casos de seroconversión de dicha enfermedad.Método: Este estudio se realizó desde el 1 de julio de 2017 hasta el 31 de marzo de 2018. Se llevó a cabo un estudio de cohortes prospectivo (población expuesta: capturadores de cangrejo rojo; población no expuesta: población general) en el municipio de Isla Mayor (Sevilla, España). Previo consentimiento informado, se invitó a la población al estudio de prevalencia mediante la técnica cualitativa ELISA. Los que tuvieron serología negativa fueron incluidos en el estudio de cohortes. Ambas cohortes se siguieron clínicamente y a los casos sintomáticos se les realizó serología. A los capturadores de cangrejo rojo se les tomó una segunda muestra de suero al final del seguimiento para detectar asintomáticos. La serovariedad se confirmó mediante aglutinación microscópica. Se realizó un análisis descriptivo bivariado y se calcularon la incidencia acumulada y el riesgo relativo. La serología positiva se tomó como variable dependiente.Resultados:Se incluyeron en el estudio 278 personas, de las que 92 constituían la cohorte de capturadores y 186 la de población general. El 46,8% de la muestra eran mujeres, aunque entre los capturadores de cangrejo rojo estas solo representaban el 29,3%. La edad media de la muestra fue de 45,1 (± 16,4) años. Se detectaron nueve seroconversiones: ocho en capturadores de cangrejo rojo y una en población general. Por lo tanto, la incidencia acumulada fue de 8,7% en capturadores de cangrejo rojo y de 0,5% en población general, siendo el riesgo relativo de 16,2 (intervalo de confianza del 95%: 2,1-127,4). El coste total de la asistencia sanitaria y de las pérdidas por enfermedad asociadas a la leptospirosis fue de 1568 € por caso(AU)

Objective: To find out whether the leptospirosis incidence rate among red swamp crayfish collectors in the harvesting season is higher than in the general population, and to identify risk factors and assess the direct and indirect health costs associated with leptospirosis seroconversion. Method: This study was carried out between 1 July 2017 and 31 March 2018 in the municipality of Isla Mayor (Seville, Spain). It took the form of a prospective cohort study (exposed population: swamp crayfish collectors; non-exposed population: general population). The population was invited to take part in a prevalence study to be conducted using the ELISA qualitative technique, and informed consent was obtained from those who agreed. Negative serology cases were then included in the cohort study. Both cohorts were monitored clinically and symptomatic cases were serology tested. A second serum sample was taken from the swamp crayfish collectors at the end of the monitoring period to detect asymptomatic cases. Serovars were confirmed by microscopic agglutination testing. A bivariate descriptive analysis was carried out and cumulative incidence and relative risk were calculated, with positive serology being taken as the dependent variable. Results: A total of 278 people were included in the study, of whom 92 made up the swamp crayfish collectors cohort and 186 the general population cohort. Women made up 46.8% of the sample, but only 29.3% of the collectors cohort. The mean age was 45.1 (±16.4) years. Nine cases of seroconversion were detected: eight among swamp crayfish collectors and one in the general population. Overall cumulative incidence was therefore 3.2%: 8.7% in the exposed group and 0.5% in the non-exposed group. Relative risk was 16.2% (95% confidence interval: 2.1-127.4). The total cost of medical assistance and illness-related losses associated with leptospirosis was 1568€/case. (AU)

Antiradical and antiulcer effect of Sonneratia apetala Buch-Ham leaves against alcohol induced gastric mucosal injury / Efecto antirradical y antiulceroso de las hojas de Sonneratia apetala Buch-Ham contra la lesión de la mucosa gástrica inducida por el alcohol

Introducción: Sonneratia apetala Buch-Ham es un verdadero habitante de los manglares en Sunderban indio y se utiliza en la medicina popular para los trastornos digestivos. Método: El extracto hidrometanólico (20:80) de hojas de Sonneratia apetala (SA) se estandarizó químicamente por HPTLC y se evaluó por sus propiedades antirradicales y gastroprotectoras. Se determinaron los fenólicos y flavonoides presentes en SA y se evaluaron las actividades antirradicales mediante métodos in vitro como, DPPH (1,1-difenil-2-picrilhidrazilo), óxidos nítricos, superóxidos, hidroxilo y ABTS (2,2 / -azino-bis- Ácido 3-etilbenztiazolin-6-sulfónico). Además, se evaluó la eficacia gastroprotectora de SA en la ulceración oxidativa inducida por alcohol (50% v / v, 5 ml / kg) en ratas. Resultados: El SA químicamente estandarizado mostró presencia de compuestos polifenólicos. También mostró fuertes propiedades antirradicales. Las administraciones orales de SA (125 mg / kg y 250 mg / kg) protegieron significativamente la membrana mucosa gástrica del daño ulcerativo causado por el alcohol, similar al omeprazol (20 mg / kg) en ratas. Además, el tratamiento con SA redujo significativamente la elevación de los peróxidos de lípidos; mientras que aumentó la concentración de glutatión y catalasa en la mucosa gástrica con respecto a las ratas de control no tratadas inducidas por etanol. Conclusiones: Los resultados obtenidos de este estudio sugieren que la hoja de Sonneratia apetala tiene propiedades antioxidantes y tiene capacidad para proteger la lesión de la mucosa gástrica causada por la ingestión de alcohol. (AU)

Introduction: Sonneratia apetala Buch-Ham is a true mangrove inhabitant in Indian Sunderban and it is used in folk medicine for digestive disorders. Method: Hydro-methanolic (20:80) extract of Sonneratia apetala leaves (SA) was chemically standardized by HPTLC and evaluated for its antiradical and gastro-protective properties. Phenolics and flavonoids present in SA were determined and antiradical activities were assessed by in vitro methods like, DPPH (1,1-diphenyl-2-picrylhydrazyl), nitric oxides, superoxides, hydroxyl and ABTS (2,2/-azino-bis-3-ethyl benzthiazoline-6-sulphonic acid). Further, gastro-protective efficacy of SA was assessed in alcohol (50% v/v, 5 ml/kg) induced oxidative ulceration in rats. Results: Chemically standardized SA exhibited presence of polyphenolic compounds. It also showed strong antiradical properties. Oral administrations of SA (125 mg/kg and 250 mg/kg) significantly protected gastric mucosal membrane from ulcerative damage caused by alcohol, similar to Omeprazole (20 mg/kg) in rats. Moreover, SA treatment significantly reduced the elevation of lipid peroxides; while enhanced the concentration of glutathione and catalase in gastric mucosa in respect to ethanol induced untreated control rats. Conclusions The results obtained from this study suggest Sonneratia apetala leaf has antioxidant properties and has capabilities to protect gastric mucosal injury caused by alcohol ingestion. (AU)

Electrochemical characterization of Geobacter lovleyi identifies limitations of microbial fuel cell performance in constructed wetlands

Power generation in microbial fuel cells implemented in constructed wetlands (CW-MFCs) is low despite the enrichment of anode electricigens most closely related to Geobacter lovleyi. Using the model representative G. lovleyi strain SZ, we show that acetate, but not formate or lactate, can be oxidized efficiently but growth is limited by the high sensitivity of the bacterium to oxygen. Acetate and highly reducing conditions also supported the growth of anode biofilms but only at optimal anode potentials (450 mV vs. standard hydrogen electrode). Still, electrode coverage was poor and current densities, low, consistent with the lack of key c-type cytochromes. The results suggest that the low oxygen tolerance of G. lovleyi and inability to efficiently colonize and form electroactive biofilms on the electrodes while oxidizing the range of electron donors available in constructed wetlands limits MFC performance. The implications of these findings for the optimization of CW-MFCs are discussed (AU)

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Identification and modeling of a novel chloramphenicol resistance protein detected by functional metagenomics in a wetland of Lerma, Mexico

The exploration of novel antibiotic resistance determinants in a particular environment may be limited because of the presence of uncultured microorganisms. In this work, a culture independent approach based on functional metagenomics was applied to search for chloramphenicol resistance genes in agro-industrial wastewater in Lerma de Villada, Mexico. To this end, a metagenomic library was generated in Escherichia coli DH10B containing DNA isolated from environmental samples of the residual arsenic-enriched (10 mg/ml) effluent. One resistant clone was detected in this library and further analyzed. An open reading frame similar to a multidrug resistance protein from Aeromonas salmonicida and responsible for chloramphenicol resistance was identifi ed, sequenced, and found to encode a member of the major facilitator superfamily (MFS). Our results also showed that the expression of this gene restored streptomycin sensitivity in E. coli DH10B cells. To gain further insight into the phenotype of this MFS family member, we developed a model of the membrane protein multiporter that, in addition, may serve as a template for developing new antibiotics (AU)

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The role of plant type and salinity in the selection for the denitrifying community structure in the rhizosphere of wetland vegetation

Coastal wetlands, as transient links from terrestrial to marine environments, are important for nitrogen removal by denitrification. Denitrification strongly depends on both the presence of emergent plants and the denitrifier communities selected by different plant species. In this study, the effects of vegetation and habitat heterogeneity on the community of denitrifying bacteria were investigated in nine coastal wetlands in two preserved areas of Spain. Sampling locations were selected to cover a range of salinity (0.81 to 31.3 mS/cm) and nitrate concentrations (0.1 to 303 μM NO3-), allowing the evaluation of environmental variables that select for denitrifier communities in the rhizosphere of Phragmites sp., Ruppia sp., and Paspalum sp. Potential nitrate reduction rates were found to be dependent on the sampling time and plant species and related to the denitrifier community structure, which was assessed by terminal restriction fragment length polymorphism analysis of the functional genes nirS, nirK and nosZ. The results showed that denitrifier community structure was also governed by plant species and salinity, with significant influences of other variables, such as sampling time and location. Ruppia sp. and Phragmites sp. selected for certain communities, whereas this was not the case for Paspalum sp. The plant species effect was strongest on nirK-type denitrifiers, whereas water carbon content was a significant factor defining the structure of the nosZ-harboring community. The differences recognized using the three functional gene markers indicated that different drivers act on denitrifying populations capable of complete denitrification, compared to the overall denitrifier community. This finding may have implications for emissions of the greenhouse gas nitrous oxide (AU)

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Estudios sobre la vegetación del entorno del Balneario de Alhama de Granada (Granada) / Study about the surroundings of Alhama de Granada Baths

Se estudian los aspectos más significativos sobre la bioclimatología, biogeografía, geología y edafología del entorno del Balneario de Alhama de Granada (Granada, España), señalando la vegetación climática y sus principales etapas de sustitución. Se incluye un conjunto de referencias históricas (AU)