Endogenous regulation of the growth-rate responses of a spring-dwelling strain of the freshwater alga, Chlorella minutissima, to light and temperature.

The paper presents a laboratory investigation of the temperature- and light- dependence of autotrophic growth of the alga Chlorella minutissima. It was isolated from the storage basin of a spring in the mountains of the Massif Central, France. The alga was grown at temperatures between (10 and 35 °C) and under irradiances from 30 to 550 μmol m(-2) s(-1), under a light/dark cycle.

Effect of low power ultrasonic radiation on anaerobic biodegradability of sewage sludge.

The effect of low power ultrasonic radiation on anaerobic biodegradability of sewage sludge was investigated. For this purpose, soluble substances and variation of microbial system of sewage sludge subjected to low power ultrasonic radiation were tested. The well known hydromechanical shear forces and heating effect of low frequency ultrasound plays a major role in the sludge pre treatment process.

Detection of anatoxin-a(s) in environmental samples of cyanobacteria by using a biosensor with engineered acetylcholinesterases.

Bioassays are little used to detect individual toxins in the environment because, compared to analytical methods, these assays are still limited by several problems, such as the sensitivity and specificity of detection. We tentatively solved these two drawbacks for detection of anatoxin-a(s) by engineering an acetylcholinesterase to increase its sensitivity and by using a combination of mutants to obtain increased analyte specificity. Anatoxin-a(s), a neurotoxin produced by some freshwater cyanobacteria, was detected by measuring the inhibition of acetylcholinesterase activity.