Bioremediation potential and lead removal capacity of heavy metal-tolerant yeasts isolated from Dayet Oum Ghellaz Lake water (northwest of Algeria) / Potencial de biorremediación y capacidad de eliminación de plomo de levaduras tolerantes a metales pesados aisladas del agua del lago Dayet Oum Ghellaz (noroeste de Argelia)

Seven metal-resistant yeast strains were isolated and selected from Dayet Oum Ghellaz Lake water (northwest of Algeria) known as a highly polluted area by lead and cadmium. The yeast strains were screened on the basis of their resistance to seven heavy metals Hg, Cr, Cd, Pb, Cu, Zn, and Fe and characterized by molecular and phylogenetic analysis. The sequencing of the D1/D2 domain of the 26S rRNA genes revealed the affiliation of the seven yeast isolates to Rhodotorula mucilaginosa, Clavispora lusitaniae, and Wickerhamomyces anomalus species. All yeast strains were halotolerant as they were able to grow in 10–15% NaCl. The yeast isolates were highly resistant to the studied heavy metals and exhibited different tolerance according to the metal type. The highest minimum inhibitory concentrations (MIC) were observed in R. mucilaginosa RO7 and W. anomalus WO2 strains which were then selected for lead removal assays. The present study is the first to investigate the lead elimination by W. anomalus. The lead uptake was significantly affected by biomass concentration in a reverse relationship, with purification percentages estimated at 98.15 ± 0.9% and 97.046 ± 0.47% and removal efficiency of 12.68 ± 0.91 and 15.55 ± 0.72 mg/g for W. anomalus WO2 and R. mucilaginosa RO7, respectively. The investigated metal-tolerant yeast strains proved to be promising candidates for bioremediation processes of heavy metals. This work amends the metal-resistant yeast bank with new strains having interesting abilities to resist to relatively high concentrations of toxic heavy metals and which can be used in the near future as low-cost biosorbents.(AU)

ESTRUCTURA TÉRMICA DEL LAGO Guamués, UN LAGO TROPICAL DE ALTA MONTAÑA / THERMAL STRUCTURE OF LAKE Guamués, A TROPICAL LAKE HIGH MOUNTAIN

El presente artículo da a conocer los resultados obtenidos de una investigación desarrollada en el Lago Guamués , la finalidad fue establecer la estructura térmica a escala temporal, para lo cual se llevaron a cabo muestreos en los meses de enero a septiembre de 2013, en 10 puntos que abarcan la totalidad de ambientes presentes en el Lago. Para alcanzar el objetivo planteado se realizaron mediciones in situ de los parámetros de temperatura del agua, oxígeno disuelto y profundidad, mediante la utilización una sonda paramétrica de calidad de agua YSI 6600 V2. Se construyeron los perfiles de temperatura y oxígeno disuelto en la columna de agua y se analizó el comportamiento de la estructura térmica del lago Guamués . Entre los principales resultados obtenidos se encontró que el lago presenta periodos de mezcla completa en julio y septiembre y se encuentra estratificado en mayo, situación que se relaciona directamente con la estacionalidad, es decir, que en las épocas de lluvia favorece la mezcla completa y en épocas de verano se presenta la estratificación térmica del lago, situación que permitió clasificarlo como un lago monomíctico cálido. Finalmente, se resalta la importancia de este estudio en razón que la zona de estudio reviste de características especiales y particulares que han permitido categorizarlo como un ecosistema RAMSAR, dado todo el potencial ecosistémico manifestado en su biodiversidad, bienes y servicios ambientales brindados a la población. No obstante, los estudios existentes sobre la dinámica de la estructura térmica son inexistentes en la región y escasos en sistemas de Colombia, principalmente en lagos de alta montaña, ya que la gran mayoría de estudios se han desarrollado en lagos templados y embalses tropicales.

This article discloses the results of research conducted on Lake Guamués , the purpose was to establish the thermal structure timescale. For this, sampling was conducted in 10 locations of the lake covering all of its different environments during the months of January through September 2013. To achieve the stated objective, in situ measurements of the parameters such as water temperature, dissolved oxygen and depth were taken using a parametric probe of water quality YSI 6600 V2. Profiles of temperature and dissolved oxygen in the water column were built and the behavior of the thermal structure of the lake Guamués was analyzed. Among the main results, we found that the lake has periods of complete mixing in July and September and is stratified in May, a situation that is directly related to the seasonality that is, in the rainy season favors complete mixture and in the summertime lake thermal stratification occurs, allowing classify it as a monomictic warm lake. Finally, the importance of this study is highlighted because the study area has special and particular characteristics that have allowed categorizing it as a RAMSAR ecosystem, thanks to the ecosystemical potential manifested in its biodiversity, goods and environmental services provided to the population, however, existing studies about the dynamics of thermal structure are nonexistent in the region and few in the systems of Colombia, mainly in high mountain lakes because the majority of studies have been developed in warm lakes and tropical reservoirs.

Informe de simposio: desarrollando estrategias para detener la transmisión de la Lepra / No disponible

No disponible

Gêneros Euastrum Ehrenberg ex Ralfs e Micrasterias C. Agardh (Conjugatophyceae-Desmidiaceae) de dois ambientes amazônicos de águas pretas (Manaus, Amazonas-Brasil) / Genera Euastrum Ehrenberg ex Ralfs and Micrasterias C. Agardh (Conjugatophyceae-Desmidiaceae) from two Amazon black water environments (Manaus, Amazonas-Brazil)

Foi realizado um inventário das espécies dos gêneros Euastrum Ehrenberg ex Ralfs e Micrasterias C.Agardh de dois ambientes de águas pretas do município de Manaus, um lago de inundação (lago Tupé), e o rio Negro. As coletas foram realizadas com rede de plâncton em quatro estações no lago e uma no rio Negro, situada próxima ao lago. Um total de 93 amostras foi analisado, coletadas em escala mensal no período de março de 2002 a outubro de 2003. As espécies foram descritas e ilustradas com base na sua morfologia e morfometria. Um total de 12 espécies foi identificado, sendo cinco do gênero Euastrum (E. evolutum var. perornatum; E. gemmatum var. monocyclum; E. ornans; E. sinuosum e E. spinulosum), e sete do gênero Micrasterias (M. borgei; M. radiata var. brasiliensis; M. torreyi; M. laticeps var. acuminata; M. mahabuleshwarensis var. amazonensis; M. rotata var. rotata; M. siolii). Todas as espécies, exceto M. radiata Hassal var. brasiliensis Grönblad, foram registradas no rio Negro, enquanto no lago Tupé foi registrado, no geral, apenas sete espécies, três de Euastrum e quatro de Micrasterias.

An investigation of genera Euastrum Ehrenberg ex Ralfs and Micrasterias C.Agardh from an Amazon floodplain lake of the Negro river Basin was undertaken. The samples were collected using a plankton net in four stations on the Tupe Lake and one station near a lake on the Negro river. The species were identified and described on the basis of morphological and morphometrical characteristics. A total of 12 species were identified, five species of Euastrum genus (E. evolutum var. perornatum; E. gemmatum var. monocyclum; E. ornans; E. sinuosum; E. spinulosum), and seven of Micrasterias genus (M. borgei; M. radiata var. brasiliensis; M. torreyi; M. laticeps var. acuminata; M. mahabuleshwarensis var. amazonensis; M. rotata var. rotata; M. siolii). All species, except M. radiata Hassal var. brasiliensis Grönblad, were found in the Negro river; on the other hand, only seven species were found in the Tupé lake, three of Euastrum and four of Micrasterias.