Polyphenols obtained from Didymosphenia geminata (Lyngbye) Schmith altered the viability and proliferation of salmonids cells lines SHK-1 and CHSE-214.

Didymosphenia geminata (Lyngbye) Schmidt, also referred to as Didymo, is an invasive diatom that forms nuisance mats. Since it was first reported in our country in approximately 2010, Didymo has expanded and colonized different rivers in the Zona Austral region of Chile. Its biology and effects on ecosystems are still being studied because Didymo is an invasive algal mat that forms in a range of systems from oligotrophic austral rivers to more subtropical systems.

Characterization and Salt Response in Recurrent Halotolerant sp. SH31 Isolated From Sediments of Salar de Huasco, Chilean Altiplano.

Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity.

The activity of nitrifying microorganisms in a high-altitude Andean wetland.

High-altitude wetland holds freshwater springs, evaporitic ponds and lagoon with variable salinity and nutrients, potentially influencing the ecology of nitrifying communities. In this study, nitrifying microorganisms in Salar de Huasco (Chile) were surveyed to determine bacterial and archaeal contribution to ammonium (AO), nitrite oxidation (NO), ammonium uptake (AU) during wet and dry seasons. The activity signals from these groups were assessed by specific amoA-qPCR transcription, 15N tracer studies and addition of group specific inhibitor experiments for nitrifying microorganisms (N1-guanyl-1, 7-diaminoheptane [GC7]-archaeal specific and allylthiourea [ATU]-bacterial specific).

Microbial Activity Response to Solar Radiation across Contrasting Environmental Conditions in Salar de Huasco, Northern Chilean Altiplano.

In high altitude environments, extreme levels of solar radiation and important differences of ionic concentrations over narrow spatial scales may modulate microbial activity. In Salar de Huasco, a high-altitude wetland in the Andean mountains, the high diversity of microbial communities has been characterized and associated with strong environmental variability. Communities that differed in light history and environmental conditions, such as nutrient concentrations and salinity from different spatial locations, were assessed for bacterial secondary production (BSP, H-leucine incorporation) response from short-term exposures to solar radiation.

Bacterial Active Community Cycling in Response to Solar Radiation and Their Influence on Nutrient Changes in a High-Altitude Wetland.

Microbial communities inhabiting high-altitude spring ecosystems are subjected to extreme changes in solar irradiance and temperature throughout the diel cycle. Here, using 16S rRNA gene tag pyrosequencing (cDNA) we determined the composition of actively transcribing bacteria from spring waters experimentally exposed through the day (morning, noon, and afternoon) to variable levels of solar radiation and light quality, and evaluated their influence on nutrient recycling. Solar irradiance, temperature, and changes in nutrient dynamics were associated with changes in the active bacterial community structure, predominantly by Cyanobacteria, Verrucomicrobia, Proteobacteria, and 35 other Phyla, including the recently described Candidate Phyla Radiation (e.