摘要:

SummaryThe nucleotide sequences of theglpTgene ofEscherichia coliand its regulatory region have been elucidated and the primary structure of the glycerot‐3‐phosphate transport protein deduced. Extensive amino acid sequence homology was found with two other cytoplasmic membrane proteins: the functionally related hexose‐6‐phosphate transport protein, and the UHPC protein involved in regulating hexose‐6‐phosphate uptake. Although no significant amino acid sequence homology was found with other transport proteins, such as the arabinose, citrate, glucose, melibiose, lactose or xylose transporters, all of these proteins share a common secondary structure arrangement with the GLP T protein as they apparently contain twelve membrane‐spanning alpha‐helical segments. The promoter forglpTwas located by transcript mapping and shown to overlap a site to which cata‐bolite activator protein bindsin vitro.These findings indicate how catabolite repression may be mediated but do not explain its physiological significance in gl

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01931.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe phenotype of a recently‐described mutant (OVG), conditionally defective in chromosome partitioning and septal positioning, was originally thought to be due to a new gene (parD) mapping at 88.4 min. We have now shown that, in addition to theparDmutation, OV6 carries agyrAammutation and that this mutation is probably responsible for the gross phenotype of the mutant. We have cloned thegyrAgene, identified the GyrA protein, sequenced thegyrAgene and flanking genes, cloned and sequenced thegyrAam, mutation, and identified its truncated product, in addition, we have identified the transcriptional start point of thegyrAgene. TheE. coliGyrA protein has extensive homologies with Gyrase proteins of other organisms and weak sequence homologies with some eukaryotic cytoskeletal protein

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01932.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThealcRpositive control gene is necessary for the expression of bothalcA(coding for alcohol dehydro‐genase ADH I.) andaldA(coding for aldehyde dehydro‐genase, AldDH) inAspergillus nidulans.Using a clonedalcRprobe and Northern blots analysis we show that: (1)alcRitself is inducible; (2)alcRinducibility depends on the expression of thealcRgene Itself; and (3)alcRis subject to carbon catabolite repression and its expression Is controlled by the negatively actingcreAwide specificity gene. The repression ofalcRis sufficient to explain the cariaon catabolite repression of ADH I and Al

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01933.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryDNA probes were used to identify restriction‐fragment‐length polymorphisms (RFLPs) in DNA samples, demonstrating that theMycobacterium aviumcomplex could be clearly divided IntoM. aviumandMycobacterium intracellularestrains. Less than 2% DNA base substitution was found betweenM. aviumstrains, whereas theM. intracellularestrains had greater than 15% base substitution. The Johne's disease bacillus,Mycobacterium paratubercuiosis(American type strain), was found to be distinguishable from theM. aviumcomplex serotypes examined. Strain 18 was found to be identical toM. avium.The rat leprosy bacillus,Mycobacterium lepraemurium, was found to be very closely related, but not identical, toM. av

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01934.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryTOL plasmid PWWO of Pseudomonas putida contains two operons that specify a pathway for the degradation of aromatic hydrocarbons. The ‘upper’ operon encodes enzymes for the oxidation of toluene to benzoate and xylenes to toluates, whereas themeta‐cleavage operon specifies the further oxidation of benzoate and toluates. Transcription of the upper pathway operon (s positively regulated by the XylR protein, which is activated by toluene/xylenes and their alcohol catabolic products, in combination with the NtrA protein, a sigma factor. Expression of themeta‐operon is positively controlled by the XylS protein which is activated by meta‐pathway substrates, and is Independent of NtrA protein. Expression of themetapathway is also Induced by toluene/xylene‐activated XylR protein via a cascade regulatory system in which this protein in combination with NtrA protein stimulates transcription from thexylSgene promoter. Hyper‐production of XylS protein in turn provokes high level expression of the meta‐operon, which is independent of meta‐pathway substrates. The two promoters, which are activated by the XylR and NtrA proteins, the upper pathway promoter and thexylSgene promoter, exhibit three regions of homology centred at –12(5′–TTGCTÃG–3′), –24(5′ ‐TGGCPuT –3) and –45(5′‐TTAAATÃGPuPuGCGPuTc‐3′), with respect to their principal transcription initiation points. The possible physiological significance of activated XylR‐protein‐induced expression of the meta‐operon throu

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01935.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe nucleotide sequence of the pertussis toxin operon ofBordetella pertussis, Bordetella parapertussisandBordetella bronchiseptica, has shown that the last two species contain many common mutations and are likely to derive from a common ancestor (Arico and Rappuoli, 1987). To elucidate further the evolutionary relationships between theBordetellaspecies, we have cloned and sequenced the promoter region and the gene coding for the S1 subunit of pertussis toxin from additionalB. pertussisstrains, such as the type strain BP 18323 and two recent clinical isolates, namely strain BP 13456 from Sweden and strain BP SA1 from Italy. While the strains BP SA1 and BP 13456 are shown to differ from the publishedB. pertussissequences by only one base pair, the type strain BP 18323 contains a total of 11 base‐pair substitutions. Remarkably, 9 of the 11 substitutions found in BP 18323 are also common toB. parapertussisandB. bronchiseptica, strongly suggesting that this strain derives from the same ancestor asB. parapertussisandB. bronchiseptica.Computer analysis of the sequence data allows the construction of an evolutionary ‘tree’ showing that theB. pertussisstrains are very homogeneous and significantly distant fromB. parapertussisandB. bronchiseptica.Therefore the proposed conversion fromB. parapertussistoB. pertussisappears highly impro

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01936.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe nucleotide sequence of thevirGlocus of the nopaline type plasmid pTiC58 ofAgrobacterium tumefacienshas been determined. It contains an open reading frame (ORF) of 759 nucleotides and has 77% homology to thevirGsequences of octopine type plasmids. Differences between the sequences of the two types of Ti plasmids in the region ofvirGare located predominantly outside the ORF. The amino acid sequences inferred from the twovirGgenes show 80% homology to each other and each shows the same moderate homologies to amino acid sequences derived from genes in a family of two‐component regulatory systems. Specific differences in nucleotide and amino acid sequences as well as a structure‐function model for the gene product are discus

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01937.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryAn 1800 bp fragment of DNA from a natural ColN plasmid (pCHAP4) encompassing the colicin N structural gene (cna) and its regulatory region was subjected to nucleotide sequencing and deletion analysis. The region of DNA immediately upstream from cna contains two tandemly‐arranged and overlapping potential LexA binding sites (SOS boxes), in line with the previous demonstration thatcnaexpression is repressed by LexA protein. Deletion of the LexA binding site allowed efficient transcription ofcnafrom an upstreamlacZpromoter, whereas its presence reduced lacZ‐promotedcnaexpression to varying extents depending on the proximity oflacZpand the SOS boxes. The molecular weight of colicin N, as deduced from the nucleotide sequence, is 41696, which is ciose to the experimentally determined molecular weight of 39000. Colicin N has a glycine‐rich amino terminus similar to that found in many other colicins. Part of the glycine‐rich domain of colicin N could be replaced by an unrelated sequence devoid of glycine residues without affecting either colicin release or activity. The carboxy‐terminal half of colicin N exhibits significant homology to the C‐terminus of colicin A. The latter colicin forms pores In the cyto‐plasmic membrane ofEscherichia coli, thereby depolarizing the membrane and causing cell death. The C‐terminus of colicin A is endowed with this catalytic activity. Although colicin N was previously found to cause lysis ofEscherichia colicells, a more detailed Investigation revealed that it too depolarizes theEscherichia colicytopiasmic membrane and that lysis is a s

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01938.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryA series of deletions was constructed within the spacer region of the genes for the 16S and 23S RNA on plasmids bearing therrnBoperon. The accumulation and synthesis rates for the 16S and 23S RNAs were determined from normal growing cells and maxicells after transformation with the mutated plasmids. A marked difference In the transcription efficiency of the plasmid‐encoded ribosomal 16S and 23S RNAs was observed with cells carrying plasmids, where a sequence motif analogous to the antitermination recognition sequence (Box A) had been deleted. The overall synthesis rate of ribosomal RNAs of such cells was not altered, however, indicating that the difference in transcription rates from the plasmid genes is compensated by altered transcription rates of the corresponding chromosomal genes. In addition, the accumulation of various tRNA species encoded on rRNA operons and non rRNA operons was quantitated and compared. From these results we infer that the regulation of ribosomal RNA transcription does not only occur at the promoter sites but sequence regions possibly involved in antitermination within the operon are crucial for a coordinated synthesis of all ribosomal RNA

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01939.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryTheBscherfchia coliurinary tract Isolate C1212 contains two pyelonephritis‐associated pili (pap) DNA sequences designated here aspap‐17 andpap‐21. Each of thesepapsequences encodes antigenically‐distinct pilin monomers, pllin‐17 and pilin‐21, respectively. Most individual strain C1212 cells isolated from a single bacterial colony expressed pilin‐21. Only a small fraction (5%) of strain C1212 cells expressed pilin‐17. Most of the latter population simultaneously expressed pilin‐21, but a low percentage of cells expressed pill composed of pilin‐17 alone. In contrast, almost every E.coliK‐12 cell containing multicopy pap‐17 expressed pilin‐17 at the ceil surface. These results Indicated that the regulation of pilin‐17 expression observed for strain C1212 was lost whenpap‐17 was in the multicopy state. Transfer of pap‐17 to a single copy vector resulted in a pilin‐17 expression frequency lower than strain C1212 (1%). Using E.coliK‐12 containing single copy pap‐17, we found that the frequency of piiin‐17 expression increased about 15‐foid when pap‐21 was present in multiple copiesin trans.Subcloning of pap‐21 showed that a 2.2 kilobase‐pair DNA sequence adjacent to, but not including, the pilin‐21 structural gene was

ISSN:0950-382X    

DOI:10.1111/j.1365-2958.1987.tb01940.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY