Effect of caffeine on the rho--induction with ethidium bromide in Saccharomyces cerevisiae

Summary It is shown that caffeine antagonizes petiteinduction with ethidium bromide under non-growth conditions when administered during or after mutagenic treatment.Caffeine itself is shown to be a petite-inducing agent when cells are grown in liquid glucose-completemedium in the presence of the drug.A possible mode of action of caffeine in the ethidium bromide induced petite-mutagenesis is discussed.     

Elevated CO2 Levels do not Affect the Shell Structure of the Bivalve Arctica islandica from the Western Baltic

Shells of the bivalve Arctica islandica are used to reconstruct paleo-environmental conditions (e.g. temperature) via biogeochemical proxies, i.e. biogenic components that are related closely to environmental parameters at the time of shell formation. Several studies have shown that proxies like element and isotope-ratios can be affected by shell growth and microstructure. Thus it is essential to evaluate the impact of changing environmental parameters such as high pCO₂ and consequent changes in carbonate chemistry on shell properties to validate these biogeochemical proxies for a wider range of environmental conditions. Growth experiments with Arctica islandica from the Western Baltic Sea kept under different pCO₂ levels (from 380 to 1120 µatm) indicate no affect of elevated pCO₂ on shell growth or crystal microstructure, indicating that A. islandica shows an adaptation to a wider range of pCO₂ levels than reported for other species. Accordingly, proxy information derived from A. islandica shells of this region contains no pCO₂ related bias.     

New mutation affecting the synthesis of some membrane proteins and sporulation in Bacillus subtilis.

A new mutation, mpo, which affects the synthesis of some membrane proteins and sporulation in Bacillus subtilis was identified. The mpo mutation was tightly linked to the overproduction of membrane proteins MP32 and MP18 (molecular weights of 32,000 and 18,000, respectively) and the temperature-sensitive sporulation phenotype. Genetic analysis showed that the mpo mutation maps between the spoIIIB and lys loci.     

Why do antioxidants fail to provide clinical benefit?

The results of recent randomized trials to test the influence of antioxidants on coronary-event rates and prognosis in patients with coronary-artery disease were disappointing. In none of these studies did the use of vitamin E improve prognosis. In contrast, treatment of coronary-artery disease with angiotensin-converting-enzyme (ACE) inhibitors reduced coronary-event rates and improved prognosis. ACE inhibition prevents the formation of angiotensin II, which has been shown to be a potent stimulus of superoxide-producing enzymes in atherosclerosis. The findings suggest that inhibition of superoxide production at enzymatic levels, rather than symptomatic superoxide scavenging, may be the better choice of treatment.