Molecular cloning of promoter-containing fragments from Bacillus stearothermophilus and their expression in Escherichia coli and Bacillus subtilis

Abstract Bacillus stearothermophilus DNA fragments containing a promoter were isolated in Escherichia coli using a shuttle promoter-probe vector. The molecular sizes of the isolated fragments ranged from 0.78 to 10 kb. The 0.78 and 1.1 kb fragments were selected and examined in some detail for promoter activity in both E. coli and Bacillus subtilis by analysis of expression of erythromycin-resistance (Em^r) and β-galactosidase. The results showed that the two fragments exhibit a high promoter activity in both bacteria. In vitro promoter activity of the 1.1 kb fragment was also shown by RNA syntheses catalyzed by RNA polymerases prepared from E. coli, B. subtilis and B. stearothermophilus .     

Mg/Ca and δ18O in the brackish shallow-water benthic foraminifer Ammonia ‘beccarii’

Specimens of the benthic foraminifer Ammonia beccarii were cultured in the laboratory in order to determine the relation between temperature and Mg/Ca and oxygen isotope values in their tests. Asexual reproduction in this species provides a large number of juveniles that were allowed to grow into maturity at temperatures ranging from 10 to 27 °C and at salinities ranging from 18 to 33 PSU. The Mg/Ca in a calcite increase exponentially and δ¹⁸O decreases linearly with the temperature. Salinity has no significant impact on either Mg/Ca or δ¹⁸O. We show how the combination of these two parameters can be used to reconstruct seawater δ¹⁸O and temperature in shallow marine habitats.