| 147 matches found in 80 documents. Search time: 0.379 seconds. |
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Score: 6.00 |
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| Title: Characterization of spontaneous , In vitro-selected , rifampin-resistant mutants of Mycobacterium tuberculosis strain H37Rv .
| | Author: Morlock GP Plikaytis BB Crawford JT .
| | Journal: Antimicrob .
Agents Chemother .
Citation: V : 44 ( 12 ) P : 3298-301 Year: 2000 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11083630 Accession (PMID): 11083630 | | Abstract: Resistance to rifampin in Mycobacterium tuberculosis results from mutations in the gene coding for the beta subunit of RNA polymerase ( rpoB ) .
At least 95% of rifampin-resistant isolates have mutations in rpoB , and the mutations are clustered in a small region .
About 40 distinct point mutations and in-frame insertions and deletions in rpoB have been identified , but point mutations in two codons , those coding for Ser ( 531 ) and His ( 526 ) , are seen in about 70% of rifampin-resistant clinical isolates , with Ser ( 531 ) -to-Leu ( TCG-to-TGG ) mutations being by far the most common .
To explore this phenomenon , we isolated independent , spontaneous , rifampin-resistant mutant versions of well-characterized M tuberculosis laboratory strain H37Rv by plating 100 separate cultures , derived from a single low-density inoculum , onto rifampin-containing medium .
Rifampin-resistant mutants were obtained from 64 of these cultures .
Although we anticipated that the various point mutations would occur with approximately equal frequencies , sequencing the rpoB gene from one colony per plate revealed that 39 ( 60 . 9% ) were Ser ( 531 ) to Leu .
We conclude that , for unknown reasons , the associated rpoB mutation occurs at a substantially higher rate than other rpoB mutations .
This higher mutation rate may contribute to the high percentage of this mutation seen in clinical isolates . | Matching Sentences:
[ Sen. 7, subscore: 2.00 ]: We conclude that , for unknown reasons , the associated rpoB mutation occurs at a substantially higher rate than other rpoB mutations .
[ Sen. 1, subscore: 1.00 ]: Resistance to rifampin in Mycobacterium tuberculosis results from mutations in the gene coding for the beta subunit of RNA polymerase ( rpoB ) .
[ Sen. 2, subscore: 1.00 ]: At least 95% of rifampin-resistant isolates have mutations in rpoB , and the mutations are clustered in a small region .
[ Sen. 3, subscore: 1.00 ]: About 40 distinct point mutations and in-frame insertions and deletions in rpoB have been identified , but point mutations in two codons , those coding for Ser ( 531 ) and His ( 526 ) , are seen in about 70% of rifampin-resistant clinical isolates , with Ser ( 531 ) -to-Leu ( TCG-to-TGG ) mutations being by far the most common .
[ Sen. 6, subscore: 1.00 ]: Although we anticipated that the various point mutations would occur with approximately equal frequencies , sequencing the rpoB gene from one colony per plate revealed that 39 ( 60 . 9% ) were Ser ( 531 ) to Leu .
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Score: 6.00 |
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| Title: Existence of three regulatory regions each containing a highly conserved motif in the promoter of plastid-encoded RNA polymerase gene ( rpoB ) .
| | Author: Inada H Seki M Morikawa H Nishimura M Iba K | | Journal: Plant J Citation: V : 11 ( 4 ) P : 883-90 Year: 1997 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9161043 Accession (PMID): 9161043 | | Abstract: The plastid gene rpoB encodes a plastid-specific , DNA-dependent RNA polymerase .
A study of a barley mutant , albostrians , indicated that rpoB itself is transcribed by a nuclear-encoded RNA polymerase .
However , the molecular nature of the nuclear-encoded RNA polymerase and mechanisms of the transcriptional regulation of rpoB expression have not been elucidated .
Using an in vivo transient assay system for gene expression in plastids , the 5-flanking region of rpoB from Arabidopsis thaliana in plastids of cultured BY-2 tobacco cells was analyzed .
A series of deletion analyses of the 5-flanking region indicated that there were two positive and one negative regulatory regions for rpoB expression .
Comparison of the 5-flanking sequences of rpoB among several plant species revealed the existence of three conserved motifs in these regions . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: The plastid gene rpoB encodes a plastid-specific , DNA-dependent RNA polymerase .
[ Sen. 2, subscore: 1.00 ]: A study of a barley mutant , albostrians , indicated that rpoB itself is transcribed by a nuclear-encoded RNA polymerase .
[ Sen. 3, subscore: 1.00 ]: However , the molecular nature of the nuclear-encoded RNA polymerase and mechanisms of the transcriptional regulation of rpoB expression have not been elucidated .
[ Sen. 4, subscore: 1.00 ]: Using an in vivo transient assay system for gene expression in plastids , the 5-flanking region of rpoB from Arabidopsis thaliana in plastids of cultured BY-2 tobacco cells was analyzed .
[ Sen. 5, subscore: 1.00 ]: A series of deletion analyses of the 5-flanking region indicated that there were two positive and one negative regulatory regions for rpoB expression .
[ Sen. 6, subscore: 1.00 ]: Comparison of the 5-flanking sequences of rpoB among several plant species revealed the existence of three conserved motifs in these regions .
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Score: 6.00 |
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| Title: Determination of Coxiella burnetii rpoB sequence and its use for phylogenetic analysis .
| | Author: Mollet C Drancourt M Raoult D | | Journal: Gene Citation: V : 207 ( 1 ) P : 97-103 Year: 1998 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9511749 Accession (PMID): 9511749 | | Abstract: The nucleotide sequence of the rpoB , encoding the beta-subunit of RNA polymerase of the obligate intracellular bacterium Coxiella burnetii , was determined using a polymerase chain reaction amplification and direct sequencing methodology .
Comparison between C burnetii and other eubacterial rpoB sequences indicated sequence similarity ranging from 53 . 6% to 67 . 6% .
Coxiella burnetii rpoB consists of 4128 base pairs with a 45 . 3% GC content encoding 1375 amino acids with a calculated molecular mass of 153 . 67 kDa .
Comparison of 512 bases of the rpoB variable region I , from eight C burnetii strains isolated from various sources , revealed fewer than four base differences , although the distribution of these did not correlate with previously determined genotypic groupings with the species .
Phylogenetic analysis of C burnetii based on comparison of its rpoB sequence with sequences available for other bacteria is consistent with those previously derived from 16S rRNA gene sequence , and indicate that C burnetii belongs to the gamma-group of Proteobacteria .
Furthermore , phylogeny inferred from comparison of RpoB , or homologous sequences including Archae , Bacteria and Eukarya , concurred with these results . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: The nucleotide sequence of the rpoB , encoding the beta-subunit of RNA polymerase of the obligate intracellular bacterium Coxiella burnetii , was determined using a polymerase chain reaction amplification and direct sequencing methodology .
[ Sen. 2, subscore: 1.00 ]: Comparison between C burnetii and other eubacterial rpoB sequences indicated sequence similarity ranging from 53 . 6% to 67 . 6% .
[ Sen. 3, subscore: 1.00 ]: Coxiella burnetii rpoB consists of 4128 base pairs with a 45 . 3% GC content encoding 1375 amino acids with a calculated molecular mass of 153 . 67 kDa .
[ Sen. 4, subscore: 1.00 ]: Comparison of 512 bases of the rpoB variable region I , from eight C burnetii strains isolated from various sources , revealed fewer than four base differences , although the distribution of these did not correlate with previously determined genotypic groupings with the species .
[ Sen. 5, subscore: 1.00 ]: Phylogenetic analysis of C burnetii based on comparison of its rpoB sequence with sequences available for other bacteria is consistent with those previously derived from 16S rRNA gene sequence , and indicate that C burnetii belongs to the gamma-group of Proteobacteria .
[ Sen. 6, subscore: 1.00 ]: Furthermore , phylogeny inferred from comparison of RpoB , or homologous sequences including Archae , Bacteria and Eukarya , concurred with these results .
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Score: 5.00 |
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| Title: Multiple mutations in the rpoB gene of Mycobacterium leprae strains from leprosy patients in Thailand .
| | Author: Ramasoota P Wongwit W Sampunachot P Unnarat K Ngamying M Svenson SB .
| | Journal: Southeast Asian J Trop . Med . Public Health Citation: V : 31 ( 3 ) P : 493-7 Year: 2000 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11289008 Accession (PMID): 11289008 | | Abstract: A new finding is reported of multiple mutations in the rpoB gene of 9 Mycobacterium leprae strains from leprosy patients in Thailand , who did not respond to therapy even when rifampicin , the main drug in multi-drug therapy was used .
By means of sequence analysis of 9 Thai M leprae strains , various mutations in 289 bps of the rpoB gene revealed forms of mutation never before described , such as multiple mutations ( ie , mutation at two , three , six , seven , eight and nine positions in the rpoB gene ) , most of which were point-mutation substitutions ( a few of which were silent ) , and some insertions .
This investigation demonstrates that mutation in the rpoB gene of M leprae strains from Thailand involves more variety than previously reported for rpoB mutation patterns in rifampicin resistance M leprae strains . | Matching Sentences:
[ Sen. 2, subscore: 2.00 ]: By means of sequence analysis of 9 Thai M leprae strains , various mutations in 289 bps of the rpoB gene revealed forms of mutation never before described , such as multiple mutations ( ie , mutation at two , three , six , seven , eight and nine positions in the rpoB gene ) , most of which were point-mutation substitutions ( a few of which were silent ) , and some insertions .
[ Sen. 3, subscore: 2.00 ]: This investigation demonstrates that mutation in the rpoB gene of M leprae strains from Thailand involves more variety than previously reported for rpoB mutation patterns in rifampicin resistance M leprae strains .
[ Sen. 1, subscore: 1.00 ]: A new finding is reported of multiple mutations in the rpoB gene of 9 Mycobacterium leprae strains from leprosy patients in Thailand , who did not respond to therapy even when rifampicin , the main drug in multi-drug therapy was used .
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Score: 5.00 |
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| Title: Use of rpoB and 16S rRNA genes to analyse bacterial diversity of a tropical soil using PCR and DGGE .
| | Author: Peixoto RS da Costa Coutinho HL Rumjanek NG Macrae A Rosado AS .
| | Journal: Lett . Appl . Microbiol . Citation: V : 35 ( 4 ) P : 316-20 Year: Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub12358695 Accession (PMID): 12358695 | | Abstract: AIM : To evaluate the rpoB gene as a biomarker for PCR-DGGE microbial analyses using soil DNA from the Cerrado , Brazil .
METHODS : DNA extraction from soil was followed by Polymerase Chain Reaction ( PCR ) amplification of rpoB and 16S rRNA genes .
PCR products were compared by Denaturing Gradient Gel Electrophoresis ( DGGE ) to compare gene/community profiles .
RESULTS : The rpoB DGGE profiles comprised fewer bands than the 16S rDNA profiles and were easier to delineate and therefore to analyse .
Comparison of the community profiles revealed that the methods were complementary .
CONCLUSIONS , SIGNIFICANCE AND IMPACT OF THE STUDY : The gene for the beta subunit of the RNA polymerase , rpoB , is a single copy gene unlike 16S rDNA .
Multiple copies of 16S rRNA genes in bacterial genomes complicate diversity assessments made from DGGE profiles .
Using the rpoB gene offers a better alternative to the commonly used 16S rRNA gene for microbial community analyses based on DGGE . | Matching Sentences:
[ Sen. 1, subscore: 1.00 ]: AIM : To evaluate the rpoB gene as a biomarker for PCR-DGGE microbial analyses using soil DNA from the Cerrado , Brazil .
[ Sen. 2, subscore: 1.00 ]: METHODS : DNA extraction from soil was followed by Polymerase Chain Reaction ( PCR ) amplification of rpoB and 16S rRNA genes .
[ Sen. 4, subscore: 1.00 ]: RESULTS : The rpoB DGGE profiles comprised fewer bands than the 16S rDNA profiles and were easier to delineate and therefore to analyse .
[ Sen. 6, subscore: 1.00 ]: CONCLUSIONS , SIGNIFICANCE AND IMPACT OF THE STUDY : The gene for the beta subunit of the RNA polymerase , rpoB , is a single copy gene unlike 16S rDNA .
[ Sen. 8, subscore: 1.00 ]: Using the rpoB gene offers a better alternative to the commonly used 16S rRNA gene for microbial community analyses based on DGGE .
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