Oxidative stress biomarkers in the Mediterranean pond turtle (Mauremys leprosa) reveal contrasted aquatic environments in Southern France.

Increasing anthropogenic activities, like agricultural practices, constitute the main causes of the loss of water quality and disruption of freshwater ecosystems. High concentrations of pesticides, as shown under experimental conditions, can indeed impact freshwater animals. In Southern France, especially in the Pyrénées-Orientales department, because agricultural activities are mainly based on fruit crops and vineyards, glyphosate and AMPA were detected in some watercourses. Thereby we investigated the effects of degraded waters on the physiology of the endemic endangered freshwater species, namely the Mediterranean pond turtle Mauremys leprosa, in contrasted environments along the same rivers on the one hand and between different rivers on the other. We measured the activity and gene expression of two enzymes involved in the oxidative detoxification processes, namely the Catalase and the Superoxide dismutase. We showed significant variations in the Catalase gene expression and activity within turtles of the Fosseille River depending of their location, i.e. upstream or downstream of the wastewater treatment plants (WTP). Because agricultural environments are similar all along this river, they can no be longer considered as the unique source of turtle stress. The processed waters discharged by the WTP, which contribute to watercourses degradation, could therefore considerably impact the biodiversity of the freshwater environments.

BOD biosensor based on the yeast Debaryomyces hansenii immobilized in poly(vinyl alcohol) modified by N-vinylpyrrolidone.

An amperometric biosensor for assessing the biochemical oxygen demand (BOD) was formed by immobilizing Debaryomyces hansenii VKM Y-2482 yeast cells in poly(vinyl alcohol) modified by N-vinylpyrrolidone. Modification provided for a high sensitivity and stability of the bioreceptor. A high oxidative activity of the receptor element and the absence of any toxic effect of assayed compounds were shown for 34 substrates (alcohols, carbohydrates, carboxylic acids, amino acids, nitrophenols and surfactants) that may occur in wastewaters. Estimates of the measurement range and region of the linear dependence of signals on the BOD level, pH and temperature sensitivities, dependences of signals on concentrations of salts, stability, Michaelis kinetic constants and assay rates were obtained. The BOD values determined by the biosensor in assayed wastewater samples were shown to have a high correlation with those obtained by the standard dilution method.

Ocorrencia de micobacterias em aguas poluidas com residuos industriais e domesticos / Occurrence of mycobacteria in waters pollution with industrial and domestic residues

Foram isoladas 158 cepas de micobacterias a partir de amostras de agua poluida notadamente com residuos de petroleo apos a depuração com hidroxido de sodio 4 por cento (111 cepas) ou cloreto de benzalconio de 0,34 por cento (47 cepas) A maioria das micobacterias isoladas comportou se como pertencente ao grupo III de Runyon (78 cepas), seguindo-se as de crescimento rapido 61 cepas e as escotocromogenicas, de crescimento lento 19 cepas. Aproiximadamente 32 por cento das cepas foi caracterizada como micobacterias potencialmente patogenicas incluindo M avium intracelulare 3,8 por cento. M scrofulaceum 6,3 por cento e m fortutum 22,2 por cento. Conclui se que a agua do Rio de Jacare esta contaminada com micobacterias potencialmente patogenicas podendo servir como fonte de doença humana.