Acid tolerance and acid‐neutralizing activity of Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum

Abstract

The tolerance to acid and the acid-neutralizing activity of three important periodontopathic bacteria, Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum were studied. P. gingivalis strains grew only at neutral pH and did not utilize glucose, whereas strains of P. intermedia and F. nucleatum could grow under acidic conditions and increased their growth by utilizing glucose. P. gingivalis tended to raise the culture pH during growth. P. intermedia and F. nucleatum raised the culture pH during growth in the absence of glucose, while in the presence of glucose they decreased the pH. Resting cell suspensions of all the bacteria raised the pH in the presence of tryptone and casamino acids. Acid-neutralizing activity was confirmed by measuring base production at a fixed pH with a pH-stat. During neutralization, the cells produced cytotoxic substrates, ammonia and organic acids (butyric, isobutyric and isovaleric acids by P. gingivalis; isovaleric and succinic acids by P. intermedia; propionic and butyric acids by F. nucleatum). These findings suggest that deamination of amino acids into ammonia and organic acids occurs simultaneously with base production, resulting in acid neutralization. These results could partially explain the survival of P. intermedia and F. nucleatum in both supragingival and subgingival plaque and the apparent restriction of P. gingivalis to subgingival plaque. The former bacteria may aid in creation of an environment fostering colonization of subgingival plaque by P. gingivalis.

Correlation of Salivary pH, Incidence of Dental Caries and Periodontal Status in Diabetes Mellitus Patients: A Cross-sectional Study

“…This study is in accordance with study done by Poplawaska-Kita A et al, who reported that there was an increased risk of periodontitis in patients with diabetes mellitus [21]. Also, the reduction in salivary pH which was evident in our study may increase the growth of periodontal-pathogens which is in accordance with that of Takahashi et al, Fujikawa et al, and Galgut [22][23][24][25].…”

“…Similarly, pH of saliva in patients with periodontitis is more acidic than control group [Table/ Fig-2], which is similar to the study done by Sharmila Baliga et al, who reported that pH of saliva in patients with chronic generalized periodontitis was more acidic than pH of saliva of the control group [3]. This can be explained in accordance with the study conducted by Takahashi et al, that the microorganism which are responsible for periodontitis have a favourable environment for growth in an acidic pH such as P. gingivalis grows at a pH of 6.5-7.0, P. intermedia grows at a pH of 5.0-7.0 and F. nucleatum grows at a pH of 5.5-7.0 [22,23].…”

Metabolic Pathways for Cytotoxic End Product Formation from Glutamate- and Aspartate-Containing Peptides by Porphyromonas gingivalis

“…2). Although Shah and Williams (47) reported that P. gingivalis had fumarate reductase and produced succinate from aspartate, succinate was not the main end product of this bacterium in our study as well as most previous reports (18,33,54). Acyl-CoA:acetate CoA-transferase was found to convert succinate to succinyl-CoA by using acetyl-CoA as a CoA donor, indicating that a part of succinate derived from aspartate can be readily converted to succinyl-CoA (reaction 7 in Fig.…”

“…The perchloric acid-acidified supernatant was diluted with 0.2 N HCl. Carboxylic acids, including formic, acetic, propionic, pyruvic, lactic, malic, succinic, butyric, isobutyric, valeric, and isovaleric acids, were analyzed with a carboxylic acid analyzer (model S-3000X; Tokyo Rikakikai, Tokyo, Japan), as described previously (53,54). Ammonia was assayed enzymatically using glutamate dehydrogenase by the method of Bergmeyer (4).…”

Citrullination as a plausible link to periodontitis, rheumatoid arthritis, atherosclerosis and Alzheimer’s disease

“…By adopting a more resilient phenotype through selecting different signalling pathway molecules, in vitro studies demonstrate the survival ‘instincts’ of this pathogen under both poor and sufficient bioavailability of haemin [25,26]. This keystone pathogen with its companion species is associated with the initiation and progression of chronic periodontitis by secretion of several virulence factors including Rgps and PPAD in the periodontal pocket [27,28]. …”