Ferrous Iron Oxidation by Salt-Tolerant “Thiobacillus prosperus”

Growth on ferrous iron of a new isolate of the halotolerant acidophile “Thiobacillus prosperus” occurred with a substrate oxidation rate similar to that of Acidithiobacillus ferrooxidans, but with a requirement for salt (NaCl). These observations contrast with the previous description of “T. prosperus” in which a salt requirement was not noted and growth on ferrous iron was described as poor. As well as similar capacities for iron oxidation, these species were shown to possess similar clusters of genes (the rus operon) that encode proteins likely to be involved in transfer of electrons from ferrous iron. There were some differences in the organization of the genes and one of them that encodes a cytochrome c in At. ferrooxidans was absent from the “T. prosperus” cluster.

The High Salt Requirement of the Moderate Halophile Chromohalobacter salexigens DSM3043 Can Be Met Not Only by NaCl but by Other Ions

ABSTRACT The growth rate of Chromohalobacter salexigens DSM 3043 can be stimulated in media containing 0.3 M NaCl by a 0.7 M concentration of other salts of Na+, K+, Rb+, or NH4 +, Cl−, Br−, NO3 −, or SO4 2− ions. To our knowledge, growth rate stimulation by a general high ion concentration has not been reported for any organism previously.

Characterization of a Baculovirus Alkaline Nuclease

ABSTRACT All baculovirus genomes sequenced to date encode a homolog of an alkaline nuclease that has been characterized in theHerpesviridae. In this report we describe the characterization of the alkaline nuclease (AN) homolog of theAutographa californica multinucleocapsid nucleopolyhedrovirus (AcMNPV) (open reading frame 133). His-tagged AN constructs were expressed in recombinant baculoviruses and affinity purified, and then their enzymatic activity was characterized. AN was found to degrade linear DNA at alkaline pH, preferred Mg2+ over Mn2+, had optimal activity at 35°C, and did not appear to have a salt requirement. To rule out contamination by the endogenous baculovirus gene product or a cellular enzyme, point mutations were introduced into a highly conserved domain of the gene. These mutations were found to markedly reduce or eliminate most of the activity of the affinity-purified enzyme. An antibody generated against the protein was used to analyze its expression by Western blot analysis. AN was found to be expressed at low levels by 12 h postinfection, with maximal expression at 24 h postinfection. Attempts to generate a virus with this gene inactivated were unsuccessful, suggesting that AN may be encoded by an essential gene.

Theoretical Performance of a Solar Pond With Enhanced Ground Energy Storage

A method was proposed earlier by the authors for the enhancement of energy storage in the ground beneath solar ponds employing the trapezoidal-shaped trenches at the bottom of the pond. The theoretical performance of the solar pond with trapezoidal trenches is presented for constant and variable energy extraction patterns. The results indicate that the trenches could be effective in reducing the thickness of lower convective layer and hence the salt requirement of the pond. However, the effectiveness of the trenches seems to be dependent on the energy extraction pattern. For the constant extraction pattern of 63.9 W m−2, it is found that 36.5 percent reduction in the salt requirement can be achieved with 3-m deep trenches compared to the flat-bottom pond. For the variable extraction pattern, the reduction was only 21.5 percent.