From Science Daily:
Microorganisms can better withstand the heavy metal uranium when glutathione is present, a molecule composed of three amino acids. Scientists from the German based Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Bern in Switzerland have now proven this resilience by closely examining cell heat balance. They discovered that glutathione is an effective decontamination agent. The studies provide important insights into bioremediation of mining waste piles and other contaminated areas with the help of bacteria or plants.
Living cells are small power stations in which various chemical reactions take place, releasing tiny amounts of heat. Metabolism is stimulated when the cells are exposed to uranium, without, however, leading to increased growth. This extra effort is detectable in the organisms as increased heat emission — signaling their fight against the toxin. The four-person team from Dresden and Bern (Dr. Muhammad H. Obeid, Dr. Jana Oertel, Prof. Marc Solioz, Prof. Karim Fahmy) established a highly sensitive method, known as microcalorimetry, with which this power can be measured — even if it lies only in the microwatt (a millionth of a watt) range.
Through their tests, the researchers furthermore determine the culture cell count and thus register how the cells divide and grow. Karim Fahmy summarizes the results: “We have found out that the metabolism with uranium becomes less efficient. The cells produce more heat but not more cells. They’re virtually running a temperature!” The organisms clearly use their energy for defense mechanisms rather than for growth. A completely different picture emerges when glutathione…