Abstract:
:The mitis group streptococci (MGS) are widespread in the oral cavity and are traditionally associated with oral health. However, these organisms have many attributes that contribute to the development of pathogenic oral communities. MGS adhere rapidly to saliva-coated tooth surfaces, thereby providing an attachment substratum for more overtly pathogenic organisms such as Porphyromonas gingivalis, and the two species assemble into heterotypic communities. Close physical association facilitates physiologic support, and pathogens such as Aggregatibacter actinomycetemcomitans display resource partitioning to favour carbon sources generated by streptococcal metabolism. MGS exchange information with community members through a number of interspecies signalling systems including AI-2 and contact dependent mechanisms. Signal transduction systems induced in P. gingivalis are based on protein dephosphorylation mediated by the tyrosine phosphatase Ltp1, and converge on a LuxR-family transcriptional regulator, CdhR. Phenotypic responses in P. gingivalis include regulation of hemin uptake systems and gingipain activity, processes that are intimately linked to the virulence of the organism. Furthermore, communities of S. gordonii with P. gingivalis or with A. actinomycetemcomitans are more pathogenic in animal models than the constituent species alone. We propose that MGS should be considered accessory pathogens, organisms whose pathogenic potential only becomes evident in the context of a heterotypic microbial community.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Whitmore SE,Lamont RJdoi
10.1111/j.1365-2958.2011.07707.xsubject
Has Abstractpub_date
2011-07-01 00:00:00pages
305-14issue
2eissn
0950-382Xissn
1365-2958journal_volume
81pub_type
杂志文章,评审abstract::The 136 codon (408 bp) denA gene encoding endonuclease II (Endoll) of bacteriophage T4 was unambiguously identified through sequencing and subsequent cloning. Endoll prepared from cloned DNA through coupled in vitro transcription-translation nicked and cut DNA in vitro in a sequence-specific manner. In vitro (and in v...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1999.01281.x
更新日期:1999-03-01 00:00:00
abstract::Heteroduplexes between the DNA molecules of 12 lambdoid phages were analysed by electron microscopy. The positions of the regions of base sequence homology between the DNA molecules divide them into 35 segments, most of which have a number of alternative forms (alleles), which in general must be functionally homologou...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1990.tb00712.x
更新日期:1990-08-01 00:00:00
abstract::SsrA is a tmRNA involved in tagging polypeptides on stalled ribosomes. The resulting fusion proteins are then degraded. We purified endogenous SsrA-tagged proteins by means of a genetically engineered SsrA and identified some of them. Analysis of the proteins suggested that they are tagged at their C-terminal extremit...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.2002.03045.x
更新日期:2002-08-01 00:00:00
abstract::Legionella pneumophila can replicate inside amoebae and also alveolar macrophages to cause Legionnaires' Disease in susceptible hosts. When nutrients become limiting, a stringent-like response coordinates the differentiation of L. pneumophila to a transmissive form, a process mediated by the two-component system LetA/...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.2003.03706.x
更新日期:2003-10-01 00:00:00
abstract::The nucleotide sequence of the mip genes and their inferred amino acid sequences were determined from 35 Legionella species and compared with the published sequences for L. pneumophila, L. micdadei and L. longbeachae. The sequences were 69-97% conserved at the nucleotide level and 82-99% at the amino acid level, with ...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1997.5471908.x
更新日期:1997-09-01 00:00:00
abstract::Many fungi undergo a morphological transition to filamentous growth in response to limiting nutrient conditions. Constitutively elongated Saccharomyces cerevisiae mutants (elm) have been isolated; the ELM1 gene encodes a putative serine/threonine protein kinase. A novel allele, elm1-15, has been isolated in an S288C-d...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1997.6231990.x
更新日期:1997-11-01 00:00:00
abstract::RpoS, an alternative primary sigma factor, has been shown to be regulated at multiple levels, including transcription, translation and protein stability. Here, we present evidence that suggests that RpoS is regulated at yet another level by the product of the crl gene. The crl gene was first thought to encode the majo...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1998.01007.x
更新日期:1998-09-01 00:00:00
abstract::The lipopolysaccharide (LPS) of H. influenzae is highly variable. Much of the structural diversity is derived from phase variation, or high frequency on-off switching, of molecules attached during LPS biosynthesis. In this study, we examined the dynamics of LPS phase variation following exposure to human serum as a so...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.12214
更新日期:2013-05-01 00:00:00
abstract::A series of lipoproteins was detected in the membrane fraction of Yersinia enterocolitica W227, a typical strain from serotype O:9. At least two of them, YlpA and YlpB, are encoded by the pYV plasmid. The sequence of ylpA reveals the presence of a typical lipoprotein signal peptide. The mature YlpA protein would be 22...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1990.tb02070.x
更新日期:1990-09-01 00:00:00
abstract::Motile bacteria sense their physical and chemical environment through highly cooperative, ordered arrays of chemoreceptors. These signalling complexes phosphorylate a response regulator which in turn governs flagellar motor reversals, driving cells towards favourable environments. The structural changes that translate...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.12309
更新日期:2013-09-01 00:00:00
abstract::Nitrogen-regulated genes in enterobacteria are positively controlled by the transcriptional activator of σ(N) -dependent promoters NtrC, either directly or indirectly, through the dual regulator Nac. Similar to enterobacteria, gdhA encoding glutamate dehydrogenase from Pseudomonas putida is one of the few genes that i...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2010.07329.x
更新日期:2010-10-01 00:00:00
abstract::Lipopolysaccharides (LPS), particularly the O-antigen component, are one of many virulence determinants necessary for Shigella flexneri pathogenesis. O-antigen biosynthesis is determined mostly by genes located in the rfb region of the chromosome. The rfc/wzy gene encodes the O-antigen polymerase, an integral membrane...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1998.00884.x
更新日期:1998-06-01 00:00:00
abstract::Atovaquone represents a class of antimicrobial agents with a broad-spectrum activity against various parasitic infections, including malaria, toxoplasmosis and Pneumocystis pneumonia. In malaria parasites, atovaquone inhibits mitochondrial electron transport at the level of the cytochrome bc1 complex and collapses mit...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1999.01515.x
更新日期:1999-08-01 00:00:00
abstract::Genes controlling chemotaxis towards L-amino acids and D-mannitol in Rhizobium meliloti have been identified by Tn5 insertions that lead to chemotaxis-deficient mutants. The tagged genes span an 8.7 kbp region that has been sequenced. These genes are part of a large operon containing three novel open reading frames, o...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1995.tb02274.x
更新日期:1995-03-01 00:00:00
abstract::The spoIIIG gene encodes a sigma factor that determines prespore-specific gene expression during sporulation in Bacillus subtilis. Correct spatial and temporal expression of the spoIIIG gene depends on a number of other sporulation (spo) genes, but only one of these genes, spoIIIE, has a specific effect on spoIIIG exp...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1989.tb00275.x
更新日期:1989-09-01 00:00:00
abstract::In bacteria, DNA supercoil movement is restricted to subchromosomal regions or 'domains.' To elucidate the nature of domain boundaries, we analysed reaction kinetics for gammadelta site-specific resolution in six chromosomal intervals ranging in size from 14 to 90 kb. In stationary cultures of Salmonella typhimurium, ...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1998.01025.x
更新日期:1998-09-01 00:00:00
abstract::The development of new drugs for treating Pneumocystis carinii infections in AIDS patients is hampered by the lack of long-term culture systems, and by our generally limited knowledge of this organism. Recently, however, we observed significant activity of various benzimidazoles against growth of this organism in shor...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1992.tb02204.x
更新日期:1992-11-01 00:00:00
abstract::We previously identified three well-dispersed mutations, E978-K, F989-L and D1009-R within the haemolysin A signal region, located at positions -46, -35 and -15, with respect to the C-terminus, respectively. Each mutation reduces the efficiency of secretion two- to threefold leaving 30-45% of the wild-type activity. W...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1994.tb00293.x
更新日期:1994-01-01 00:00:00
abstract::The mechanisms of transcription repression and derepression in vivo are not fully understood. We have obtained evidence that begins to clarify the minimum requirements for counteracting nucleosomal repression in vivo. Location of the TATA element near the nucleosome dyad does not block RNA polymerase II transcription ...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.2000.01940.x
更新日期:2000-06-01 00:00:00
abstract::A series of plasmids carrying an IRL-kan-IRR transposable cassette, in which IRL and IRR are the left- and right-terminal sequences of IS91, have been constructed. These cassettes could be complemented for transposition with similar efficiency when IS91 transposase was provided either in cis or in trans. A total of 87...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1999.01432.x
更新日期:1999-07-01 00:00:00
abstract::Gyrase-mediated hypernegative supercoiling is one manifestation of R-loop formation, a phenomenon that is normally suppressed by topoisomerase I (topA) in Escherichia coli. Overproduction of RNase HI (rnhA), an enzyme that removes the RNA moiety of R-loops, prevents hypernegative supercoiling and allows growth of topA...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2008.06334.x
更新日期:2008-08-01 00:00:00
abstract::Soupene et al. [J. Bacteriol. (2003) 185 5611-5626] made the unexpected observation that the presence of a mutation, in the gene for the N-acetylglucosamine repressor, nagC, increased the growth rate of Escherichia coli MG1655 on galactose, an unrelated sugar. We have found that NagC, binds to a single, high-affinity ...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2008.06515.x
更新日期:2009-01-01 00:00:00
abstract::The protozoan parasite Trypanosoma brucei develops antigenic variation to escape the immune response of its host. To this end, the trypanosome genome contains multiple telomeric expression sites competent for transcription of variant surface glycoprotein genes, but as a rule only a single antigen is expressed at any t...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.2000.01844.x
更新日期:2000-04-01 00:00:00
abstract::The conserved cAMP-dependent protein kinase (PKA) plays critical roles in the regulation of morphological transitions and virulence in the human fungal pathogen Candida albicans. It has long been thought that the PKA catalytic subunit is essential for cell viability in this fungus. Paradoxically, the single adenylyl c...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.13681
更新日期:2017-07-01 00:00:00
abstract::A unique 373 bp region (igr66) between grpE and dnaK of Streptococcus mutans lacks a promoter but is required for optimal production of DnaK. Northern blotting using probes specific to hrcA, igr66 or dnaK revealed multiple transcripts produced from the dnaK operon and 5'-RACE mapped 5' termini of multiple dnaK transcr...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.13122
更新日期:2015-10-01 00:00:00
abstract::The Salmonella pathogenicity island (SPI-1) encodes approximately 35 proteins involved in assembly of a type III secretion system (T3SS) which endows Salmonella with the ability to invade eukaryotic cells. We have discovered a novel SPI-1 gene, invR, which expresses an abundant small non-coding RNA (sRNA). The invR ge...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2007.05991.x
更新日期:2007-12-01 00:00:00
abstract::Cellulosomes are key for lignocellulosic biomass degradation in cellulolytic Clostridia. Better understanding of the mechanism of cellulosome regulation would allow us to improve lignocellulose hydrolysis. It is hypothesized that cellulosomal protease inhibitors would regulate cellulosome architecture and then lignoce...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.12488
更新日期:2014-02-01 00:00:00
abstract::PspF bound to the psp enhancer activates E sigma54 holoenzyme-dependent transcription of the Escherichia coli phage-shock protein (psp) operon and autogenously represses its own sigma70-dependent transcription, thereby keeping its concentration at a low level. It has been demonstrated previously that integration host ...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1997.4791844.x
更新日期:1997-08-01 00:00:00
abstract::The bacteriocin release protein (BRP) mediates the secretion of cloacin DF13. The BRP precursor is slowly processed to yield the mature BRP and its stable signal peptide which is also involved in cloacin DF13 secretion. The function of the stable BRP signal peptide was analysed by constructing two plasmids. First, the...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1992.tb01406.x
更新日期:1992-08-01 00:00:00
abstract::Cell wall lipids of Mycobacterium tuberculosis containing multiple methylbranched fatty acids play critical roles in pathogenesis and thus offer targets for new antimycobacterial drugs. Mycocerosicacid synthase gene (mas) encodes the enzyme that produces one class of such acids. Seven mas-like genes (msls) were identi...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.2002.03119.x
更新日期:2002-09-01 00:00:00