Multidimensional antimicrobial profiles of human salivary histatins
Kalpidis, Christos D R
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Histatins are a family of small cationic proteins in human salivary secretions, abundant in histidine residues. The recently reported sequence led to the investigation of functional relationships of these proteins. Among their biological properties, the bactericidal potential of histatins had generated strong iterest. Growth inhibition and viability assays revealed that histatins were active against members of the group of Mutans Streptococci and Candida albicans, with histatin 5 being the most active. Moreover, histatins inhibited the proteolytic activity of clostripain and Porphyromonas gingivalis trypsin-like protease, P. gingivalis hemagglutination, and aggregation between P. gingivalis and Streptococcus mitis. Histatins were also able to induce histamine release from rat mast cells. A wide range of periodontopathic bacteria as we11 as Actinomyces species were employed in this study to examine the killing properties of histatins and histatin fragments, since the available data were restricted only on the group of Mutans Streptococci and several C. albicans strains. Typical broth and buffer microdilution bactericidal assays showed the inhibitory and bactericidal properties of histatins and their fragments on Actinobacillas actinomycetemcomitans, P. gingivalis, Prevotella intermedia, Bacteroides forsythus, Fusobacterium nucleatum, Peptostreptococcus micros and Actinomyces species. Bactericidal concentrations for Actinomyces were comparable with those reported for the group of Mutans Streptococci and C. albicans and fall within the physiologic concentrations of histatins in the salivary secretions. Much higher concentrations were required to observe inhibitory results for the anaerobic periodontal pathogens. In general, histatins were more potent against gram-positive bacteria and fungi than against gram-negative microorganisms. Reasons for such an expression of bactericidal profiles might include the different wall-structures between bacteria, experimental conditions, and resistance factors. [TRUNCATED]
Thesis (D.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1994 (Oral Biology)Includes bibliographical references (leaves 111-129)
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