muramidase and nitroaniline

Being exogenous environmental pollutants, nitroanilines (NAs) are highly toxic and have mutagenic and carcinogenic activity. Being lack of studies on interactions between NAs and lysozyme at molecular level, the binding interactions of lysozyme with o-nitroaniline (oNA), m-nitroaniline (mNA) and p-nitroaniline (pNA) were investigated by means of steady-state fluorescence, synchronous fluorescence, UV-vis absorption spectroscopy, as well as molecular modeling. The experimental results revealed that the fluorescence of lysozyme is quenched by oNA and mNA through a static quenching, while the fluorescence quenching triggered by pNA is a combined dynamic and static quenching. The number of binding sites (n) and the binding constant (K

Topics: Aniline Compounds; Electrons; Kinetics; Molecular Docking Simulation; Muramidase; Optical Phenomena; Protein Binding; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Spectrum Analysis; Temperature

Samples of whole saliva and dental plaque were collected from initially 10-year old subjects who participated in a 40-month cohort study investigating the effect of chewing gum usage on caries rates. The subjects represented nine cohorts of which one did not receive gum, while in eight cohorts the subjects received gum containing either xylitol, sorbitol, their mixtures, or sucrose as bulk sweeteners, the maximum sweetener consumption in the form of gums being up to 10.7 g/day, used in 3-5 daily chewing episodes. Gum usage had no significant effect on the levels of salivary protein, IgA, alpha-amylase, peroxidase, lysozyme, SCN and buffer capacity. At the endpoint, the group that received 100% xylitol pellet-shaped gum five times/day, had significantly lower levels of sucrase (p <0.05) and free sialic acid (p < 0.001) in whole saliva than at baseline. This group showed significantly (p <0.05) smaller plaque index scores at two cross-sectional measurements, and exhibited the lowest log(10) counts of salivary lactobacilli at endpoint than most other groups. The salivary levels of peptidase(s) (oligopeptidase B-like enzymes) hydrolyzing N-alpha-benzoyl-DL-arginyl-p-nitroaniline were significantly (p<0.05) or almost significantly lower in groups which received 100% xylitol pellet gums. All groups exhibited obviously an aging-related increase of salivary mutans streptococcus scores, except the above xylitol group in which the mean scores did not change.

Topics: alpha-Amylases; Aniline Compounds; Buffers; Cariostatic Agents; Chewing Gum; Child; Cohort Studies; Colony Count, Microbial; Cross-Sectional Studies; Dental Caries; Dental Plaque; Dental Plaque Index; Humans; Immunoglobulin A, Secretory; Lactobacillus; Muramidase; Peptide Hydrolases; Peroxidases; Saliva; Salivary Proteins and Peptides; Sialic Acids; Sorbitol; Streptococcus mutans; Sucrase; Sucrose; Sweetening Agents; Thiocyanates; Xylitol