Heat shock response in Actinobacillus actinomycetemcomitans

Løkensgard, I

doi:10.1016/0928-8244(94)00007-7

Cited by 18 publications

(17 citation statements)

References 14 publications

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“…There have been studies which reported (i) detection of common stress proteins in oral microorganisms (7)(8)(9), (ii) cloning of these stress proteins (10,24,43), (iii) demonstration of potent induction of bone resorption (16,30), or (iv) purification of specific heat shock proteins from various Hsp families (4,10,14,20,23,39,40,44). There have been several studies that reported an association between periodontal disease and titers of antibody to Hsp65 and Hsp90 in serum (17,22,24,31).…”

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confidence: 99%

Characterization of Heat-Inducible Expression and Cloning of HtpG (Hsp90 Homologue) of Porphyromonas gingivalis

et al. 2000

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Porphyromonas gingivalis is implicated in the etiology of periodontal disease. Associations between microbial virulence and stress protein expression have been identified in other infections. For example, Hsp90 homologues in several microbial species have been shown to contribute to virulence. We previously reported that P. gingivalis possessed an Hsp90 homologue (HtpG) which cross-reacts with human Hsp90. In addition, we found that elevated levels of serum antibody to Hsp90 stress protein in individuals colonized with this microorganism were associated with periodontal health. However, the role of HtpG in P. gingivalis has not been explored. Therefore, we cloned the htpG gene and investigated the characteristics of HtpG localization and expression in P. gingivalis. htpG exists as a single gene of 2,052 bp from which a single message encoding a mature protein of approximately 68 kDa is transcribed. Western blot analysis revealed that the 68-kDa polypeptide was stress inducible and that a major band at 44 kDa and a minor band at 40 kDa were present at constitutive levels. Cellular localization studies revealed that the 44-and 40-kDa species were associated with membrane and vesicle fractions, while the 68-kDa polypeptide was localized to the cytosolic fractions.

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Characterization of Heat-Inducible Expression and Cloning of HtpG (Hsp90 Homologue) of Porphyromonas gingivalis

et al. 2000

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“…Like other pathogenic microorganisms, an important homeostatic mechanism that both P. gingivalis and A. actinomycetemcomitans mount when exposed to elevated temperature is a heat shock response ( (Lu and McBride, 1994;Vayssier et al, 1994;Lokensgard et al, 1994). The heat shock response is a highly conserved response to elevated temperature found in both prokaryotes and eukaryotes.…”

Section: Temperaturementioning

confidence: 99%

Oral Microbiology: Environmental cues and gene expression in Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans

Champagne

Simpson

et al. 2000

Oral Diseases

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Microorganisms typically adapt to environmental cues by turning on and off the expression of virulence genes which, in turn, allows for optimal growth and survival within different environmental niches. This adaptation strategy includes sensing and responding to changes in nutrients, pH, temperature, oxygen tension, redox potential, microbial flora, and osmolarity. For a bacterium to adhere to, penetrate, replicate in, and colonize host cells, it is critical that virulence genes are expressed during certain periods of the infection process. Thus, throughout the different stages of an infection, different sets of virulence factors are turned on and off in response to different environmental signals, allowing the bacterium to effectively adapt to its varying niche. In this review, we focus on the regulation of virulence gene expression in two pathogens which have been implicated as major etiological agents in adult and juvenile periodontal diseases: Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans. Understanding the mechanisms of virulence gene expression in response to the local environment of the host will provide crucial information in the development of effective treatments targeted at eradication of these periodontal disease pathogens. Oral Diseases (2000) 6, 351-365

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“…The heat shock response in A. actinomycetemcomitans was originally studied by Koga et al (9) and by Løkensgard et al (10). Cloning and molecular characterization of the genes encoding GroEL and DnaK of A. actinomycetemcomitans have also been reported (9,11,12).…”

Section: Introductionmentioning

confidence: 99%

Expression of GroEL and DnaK Proteins during the Acquisition of a Transitory Resistance to Lethal Stresses byActinobacillus actinomycetemcomitans

Goulhen

Grenier

Mayrand

2003

Microbial Ecology in Health and Disease

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15: 120 Á/125Actinobacillus actinomycetemcomitans is a periodontopathogenic bacterium associated with active lesions of localized aggressive periodontitis. Cells of A. actinomycetemcomitans grown to mid-log phase, diluted or undiluted, and subjected to a sublethal heat stress demonstrated a partial protection to a subsequent lethal heat stress. On the contrary, stationary phase heat-stressed cells did not exhibit this transient thermal protection. Heat-stressed cells at sublethal temperature showed a higher expression of GroEL and DnaK proteins by immunoblotting, which was in agreement with de novo synthesis. A. actinomycetemcomitans was found to be more sensitive to a pH than to a heat stress. A transient protection to a lethal acid stress was demonstrated when cells were previously subjected to a sublethal acid stress. On the contrary, such transient protection did not occur for alkaline stresses. DnaK but not GroEL proteins made up a high proportion of the total protein synthesized following acid stress. The protection phenomenon is highly complex and heat shock proteins, which may help A. actinomycetemcomitans to support subsequent lethal conditions, are not expressed in the same way during the different stresses investigated.

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Heat shock response in Actinobacillus actinomycetemcomitans

Cited by 18 publications

References 14 publications

Characterization of Heat-Inducible Expression and Cloning of HtpG (Hsp90 Homologue) of Porphyromonas gingivalis

Characterization of Heat-Inducible Expression and Cloning of HtpG (Hsp90 Homologue) of Porphyromonas gingivalis

Oral Microbiology: Environmental cues and gene expression in Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans

Expression of GroEL and DnaK Proteins during the Acquisition of a Transitory Resistance to Lethal Stresses byActinobacillus actinomycetemcomitans

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