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Biogeology. How old are bacteria from the Permian age?   总被引:1,自引:0,他引:1  
Hazen RM  Roedder E 《Nature》2001,411(6834):155-156
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Stankiewicz BA 《Nature》2003,426(6964):360-363
The past two decades of the twentieth century have been very 'rocky' for the oil industry, as shown by the overall negative perception of the oil companies by the general public. Fluctuating oil prices, many rounds of staff redundancies, environmental disasters and budget cuts supported the overall image of the oil industry as being 'the technology impaired and environmentally insensible giant'. But advances and positive changes have been quietly happening in most of the oil companies. In the twenty-first century, we will witness the metamorphosis of the oil and gas companies into energy businesses - the era of cleaner and safer oil and gas production, and alternative energy resources such as wind, solar and hydrogen is already underway.  相似文献   

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The entire mitochondrial DNA sequence (mitogenome) of Russell's snapper (Lutjanus russellii) was determined using long PCR and primer-walking methodology, representing the first complete mitogenome accessioned for Lutjanid fishes (16,505 bp, GenBank Accession No. EF514208). The mitogenome was similar in gene composition and order to those of other vertebrates, having 37 structural genes, i.e., two ribosomal RNAs, 22 transfer RNAs, and 13 protein-coding genes. Phylogenetic analyses based on the mtDNA sequence of Russell's snapper supported a close relationship between Lutjaninae and Caesioninae, consistent with taxonomic hypotheses based on morphology. More studies utilizing mitogenomes are needed to resolve high-level relationships among snappers.  相似文献   

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Ever since the low energy N^ ion beam has been accepted, the mutations of ionizing radia-tion are attributable mainly to avoidance of DNA damages repair. Evidences based on in vivo proof results are limited. Using the E. coli wild type and mutator strains, the mutant frequencies suggest that base substitutions in rpoB gene are induced by the N^ implantation. A highly con-served region is selected to get the direct evidence for base substitutions by sequence of the high fi-delity PCR amplification products in mutants. Most of the mutants (90.9%, 40/44) have at least one base substitution in the amplification region. The evidences for CG to TA (55 %, 22/40), AT to GC (20%, 8/40) and TA to CG (5%, 2/40) transitions are identified. The transversions are AT to TA ( 15 %, 6/40) and GC to CG (5 %, 2/40). It is suggested that DNA cytosine methylase might play an important role in mismatch repair of DNA damage induced by N^ implantation by analysis of the mutant frequencies of mutator strains.  相似文献   

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Mitochondrial DNA ND5/6 region was studied by PCR-RFLP analysis among ten representative strains belonging to three subspecies (Cyprinus carpio carpio,Cyprinus carpio haematopterus and Cyprinus carpio rubrofuscus) of common carp(Cyprinus carpio L.)A total of 2.4kb fragment was amplified and subjected to restriction endonuclease analysis with nine restriction endonucleases subsequently.The results indicated that each subspecies owned one hyplotype and four restriction enzymes(Dde Ⅰ,HaeⅢ,Taq Ⅰ and MboⅠ)produced diagnostic restriction sites which could be used for discriminating the three subspecies and as molecular genetic markers for assistant selective breeding of common carp.  相似文献   

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