RESUMEN
Oxic methane production (OMP) has been reported to significantly contribute to methane emissions from oxic surface waters. Demethylation of organic compounds, photosynthesis-associated methane production, and (bacterio)chlorophyll reduction activity are some of the investigated mechanisms as potential OMP sources related to photosynthetic organisms. Recently, cyanobacteria have often been correlated with methane accumulation and emission in freshwater, marine, and saline systems. The Brazilian Pantanal is the world's largest wetland system, with approximately 10,000 shallow lakes, most of which are highly alkaline and saline extreme environments. We initiated this study with an overall investigation using genetic markers, from which we explored metagenomic and limnological data from the Pantanal soda for five potential OMP pathways. Our results showed a strong positive correlation between dissolved methane concentrations and bloom events. Metagenomic data and nutrients, mainly orthophosphate, nitrogen, iron, and methane concentrations, suggest that the organic phosphorous demethylation pathway has the most potential to drive OMP in lakes with blooms. A specialized bacterial community was identified, including the Cyanobacteria Raphidiopsis, although the bloom does not contain the genes to carry out this process. These data showed enough evidence to infer the occurrence of an OMP pathway at Pantanal soda lakes, including the microbial sources and their relation to the cyanobacterial blooms.
Asunto(s)
Lagos , Organofosfonatos , Brasil , Ambientes Extremos , MetanoRESUMEN
The objective of this study was to evaluate the use of piezosurgery for osteotomy and odontosection in the repair of the alveoli four months after exodontia. Fifteen young patients who needed third molars extracted were included. During the extractions, one of the teeth was included in the Piezo group, in which ultrasound motor tips were used in both procedures. The other tooth was removed with a conventional rotary instrument. The values of density of the repair regions of the right and left third molars were compared using digital panoramic radiographs. There were no significant differences (p>0.05): piezo group mean (SD) 125.7 (15.4) and control group 126.7 (21.2). The bone density of the alveoli after extraction of the lower third molars with rotary instruments and surgical ultrasound was similar in both groups.
Asunto(s)
Tercer Molar , Diente Impactado , Método Doble Ciego , Humanos , Mandíbula , Dolor Postoperatorio , Piezocirugía , Estudios Prospectivos , Extracción DentalRESUMEN
Foliar uptake of dew is likely an important mechanism of water acquisition for plants from tropical dry environments. However, there is still limited experimental evidence describing the anatomical pathways involved in this process and the effects of this water subsidy on the maintenance of gas exchange and leaf lifespan of species from seasonally dry tropical vegetation such as the Brazilian caatinga. We performed scanning electron, bright-field and confocal microscopic analyses and used apoplastic tracers to examine the foliar water uptake (FWU) routes in four woody species with different foliar phenology and widely distributed in the caatinga. Leaves of plants subjected to water stress were exposed to dew simulation to evaluate the effects of the FWU on leaf water potentials, gas exchange and leaf lifespan. All species absorbed water through their leaf cuticles and/or peltate trichomes but FWU capacity differed among species. Leaf wetting by dew increased leaf lifespan duration up to 36 days compared to plants in the drought treatment. A positive effect on leaf gas exchange and new leaf production was only observed in the anisohydric and evergreen species. We showed that leaf wetting by dew is relevant for the physiology and leaf lifespan of plants from seasonally dry tropical vegetation, especially for evergreen species.
Asunto(s)
Hojas de la Planta/metabolismo , Fotosíntesis/fisiología , Hojas de la Planta/fisiología , Estomas de Plantas/metabolismo , Estomas de Plantas/fisiología , Transpiración de Plantas/fisiología , Agua/metabolismoRESUMEN
In the districts of Caraguatatuba, Ilhabela, São Sebastião and Ubatuba, São Paulo State, Brazil, pupae were collected from 358 streams an placed in 5 ml glasses for hatching. After hatching, 1,577 specimens were obtained, and these were identifield in accordance with the characteristics of the pupa exuviae an the corresponding adult insetcs. Fourteen species were indentifield, with Simulium (Chorostilbia) pertinax being set apart as the principal target insect, due to its high incidency and wide distribution throughouth the surveyed area.