Lysozyme-mediated aggregation and lysis of the periodontal microorganism Capnocytophaga gingivalis 2010

Abstract

The ability of lysozyme to aggregate and lyse the gram-negative capnophilic periodontal microorganism Capnocytophaga gingivalis 2010 was monitored optically at 540 nm. Both hen egg white and chromatographically purified human lysozymes had significant but similar aggregation potentials for both logarithmicand stationary-phase bacteria. In general, an increase in enzyme concentration resulted in a graded increase in both the initial and maximum changes in turbidity which occurred during the reaction period. The greatest change in turbidity occurred within the initial minutes of interaction of lysozyme and the cells, and the extent of aggregation paralleled a rapid depletion of lysozyme by the suspensions during the first minute of its incubation with the bacteria. Interestingly, the muramidase inhibitors N-acetyl-D-glucosamine and histamine did not block aggregation, whereas maleylation of lysozyme completely inhibited its aggregating ability. Demaleylation, however, restored aggregation activity comparable to the native enzyme, indicating that maleylated lysozyme retained its integrity and that aggregation was primarily dependent on charge. The addition of up to physiological concentrations of NaHCO3 and NaCl to cell aggregates resulted in varying degrees of deaggregation and lysis. Surprisingly, ultrastructural analysis of lysozyme-treated cells revealed morphological changes with or without the addition of salt. Damage appeared to occur at the blunted polar end of the cells where there was a large spherical outpouching bordered by a damaged cell envelope. Damaged cells uniformly contained dense granular cytoplasmic debris. In effect, the cationic enzyme lysed C. gingivalis 2010, which was not apparent in the spectrophotometric assay. The paradoxical finding that during bacterial aggregation there was lysis may be of significance to the further elucidation of lysozyme's antibacterial role in the gingival sulcus.

“Click on the bidirectional switch”: the aptasensor for simultaneous detection of lysozyme and ATP with high sensitivity and high selectivity

“…Two analytes, lysozyme and ATP, were simultaneously detected in this aptasensor. Lysozyme can aggregate a variety of micriirganisms, which can promote the clearance of bacteria from the oral cavity 17 18 19 . The abnormal concentration of lysozyme in serum and urine is related to many diseases, such as leukemia, renal diseases, and meningitis, and it has been used as an important biomarker 20 .…”

Antivirals against animal viruses

“…Lysozyme can be present in nasal mucus, tears, saliva, and in gastric, duodenal, ileal, and colon secretions, and even in the cerebrospinal fluid of human infants [46,47]. Although this enzyme is defined as a 1,4-b-D-N-acetyl muramidase that can hydrolyze the glycosidic linkages present in bacterial peptidoglycan, lysozyme can also activate bacterial autolysins [48], act as a chitinase [49], and exhibit antiviral activity [50][51][52]. In addition, the amount of this protein in the human gut can drastically vary, depending on the emotional estate of the person [46].…”

Innate Humoral Defense Factors

“…Human lysozyme has a higher specific activity and more potent antibacterial effect against oral microorganisms than hen egg-white lysozyme (Iacono et al, 1980). However, few species of bacteria are directly lysed by lysozyme, and other modes of action independent of its enzymatic activity include the activation of bacterial autolysins, bacterial aggregation, blocking of bacterial adherence, and inhibition of acid production by oral microorganisms (Iacono et al, 1985;Laible and Germaine, 1985;Twetman et al, 1986;Wang and Germaine, 1991). Moreover, cell walls of oral streptococci weakened by cleavage of peptidoglycan (Cho et al, 1982) become susceptible to lysis by the addition of detergents or monovalent anions such as bicarbonate, fluoride, thiocyanate, and chloride, which predominate in saliva (Pollock et al, 1987).…”