A microcalorimetric technique was used to evaluate the influence of La 3+ on Halobacterium halobium R1 growth. By means of LKB 2277 bioactivity monitor, ampoule method at 37 ℃, the thermogenic curves of H...A microcalorimetric technique was used to evaluate the influence of La 3+ on Halobacterium halobium R1 growth. By means of LKB 2277 bioactivity monitor, ampoule method at 37 ℃, the thermogenic curves of Halobacterium halobium R1 growth were obtained. In order to analyze the results, the maximum power P m and the growth rate constants k were determined, showing that values of P m and k are linked to the concentration of La 3+ . Addition of low concentration of La 3+ can cause a decrease of the maximum heat production and growth rate constant. However, high concentration of La 3+ may promote growth of Halobacterium halobium R1, but at much higher concentration of La 3+ , the growth of Halobacterium halobium R1 is inhibited again. For comparison, the shapes of Halobacterium halobium R1 cell were observed by means of transmission electron microscope. According to the thermogenic curves and TEM photos of Halobacterium halobium R1 under different conditions, it is clear that metabolic mechanism of Halobacterium halobium R1 growth is changed with the addition of La 3+ .展开更多
Halobacterium halobium is a typical kind of extremely halophilic bacterium. Combined with the antibiotic resistance assay, the microcalorimetric method was used to study the promoter function of the cloned DNA fragmen...Halobacterium halobium is a typical kind of extremely halophilic bacterium. Combined with the antibiotic resistance assay, the microcalorimetric method was used to study the promoter function of the cloned DNA fragments from Halobacterium halobium J7 plasmid pHH205 in Escherichia coli TG1. The promoter probe vector, plasmid pKK232-8, was used to form the recombinants. The DNA fragment, which is the promoter for the chloramphenicol acetyl transferase （CAT） gene in plasmid pKK232-8, is about 800 bp, and the chloramphenicol resistance level presented by IC50 is about 200 μg·mL^-1, which suggests a high promoter activity. The conclusions show that there probably exist double-function or trinary-function gene promoters in Halobacterium halobium, and Archaea may contain rich genetic resources.展开更多
文摘A microcalorimetric technique was used to evaluate the influence of La 3+ on Halobacterium halobium R1 growth. By means of LKB 2277 bioactivity monitor, ampoule method at 37 ℃, the thermogenic curves of Halobacterium halobium R1 growth were obtained. In order to analyze the results, the maximum power P m and the growth rate constants k were determined, showing that values of P m and k are linked to the concentration of La 3+ . Addition of low concentration of La 3+ can cause a decrease of the maximum heat production and growth rate constant. However, high concentration of La 3+ may promote growth of Halobacterium halobium R1, but at much higher concentration of La 3+ , the growth of Halobacterium halobium R1 is inhibited again. For comparison, the shapes of Halobacterium halobium R1 cell were observed by means of transmission electron microscope. According to the thermogenic curves and TEM photos of Halobacterium halobium R1 under different conditions, it is clear that metabolic mechanism of Halobacterium halobium R1 growth is changed with the addition of La 3+ .
基金Project supported by the National Natural Science Foundation of China （Nos. 30570015, 20373051）, ＂973＂ Project （No. 2004CB719603）, Science Fund for Creative Research Group （No. 20621502 NSFC）, Science Research Foundation of Ministry of Education of China （No. [2006]8IRT0543）, and the Natural Science Foundation of Hubei Province （No. 2005ABC02）.
文摘Halobacterium halobium is a typical kind of extremely halophilic bacterium. Combined with the antibiotic resistance assay, the microcalorimetric method was used to study the promoter function of the cloned DNA fragments from Halobacterium halobium J7 plasmid pHH205 in Escherichia coli TG1. The promoter probe vector, plasmid pKK232-8, was used to form the recombinants. The DNA fragment, which is the promoter for the chloramphenicol acetyl transferase （CAT） gene in plasmid pKK232-8, is about 800 bp, and the chloramphenicol resistance level presented by IC50 is about 200 μg·mL^-1, which suggests a high promoter activity. The conclusions show that there probably exist double-function or trinary-function gene promoters in Halobacterium halobium, and Archaea may contain rich genetic resources.
