The inhibition of streptococci by lactoperoxidase, thiocyanate and hydrogen peroxide. The effect of the inhibitory system on susceptible and resistant strains of group N streptococci

Abstract

1. The growth of the lactoperoxidase-sensitive Streptococcus cremoris 972 in a synthetic medium was inhibited by lactoperoxidase and thiocyanate. The glycolysis and oxygen uptake of suspensions of Strep. cremoris 972 in glucose or lactose were also inhibited. The lactoperoxidase-resistant Strep. cremoris 803 was not inhibited under these conditions but was inhibited in the absence of a source of energy. 2. Lactoperoxidase (EC 1.11.1.7), thiocyanate and hydrogen peroxide completely inhibited the hexokinases of non-metabolizing suspensions of both strains. The inhibition was reversible, hexokinase and glycolytic activities of Strep. cremoris 972 being restored by washing the cells free from inhibitor. The aldolase and 6-phosphogluconate-dehydrogenase activities of Strep. cremoris 972 were partially inhibited but several other enzymes were unaffected. 3. The resistance of Strep. cremoris 803 to inhibition was not due to the lack of hydrogen peroxide formation, to the destruction of peroxide, to the inactivation of lactoperoxidase or to the operation of alternative pathways of carbohydrate metabolism. 4. A ;reversal factor', which was partially purified from extracts of Strep. cremoris 803, reversed the inhibition of glycolysis of Strep. cremoris 972. The ;reversal factor' also catalysed the oxidation of NADH(2) in the presence of an intermediate oxidation product of thiocyanate and was therefore termed the NADH(2)-oxidizing enzyme. 5. The NADH(2)-oxidizing enzyme was present in lactoperoxidase-resistant streptococci but was absent from lactoperoxidase-sensitive streptococci.

Comparison of the Antibacterial Activity of the Hypothiocyanite Anion towards Streptococcus lactis and Escherichia coli

“…Oram & Reiter (1966) and Mickelson (1966) suggested that the LP system, by oxidizing the thiol groups of a number of enzymes, interfered with glycolysis in some streptococci. More recently, Aune et al (1977) have examined the binding of the thiocyanate anion to bovine serum albumin in the presence of the LP system and have found that this involved the thiol groups of the protein.…”

“…Escherichia coli NCTC 9703 and Streptococcus lactis NCDO 509 were used throughout. The effect of different quantities of OSCN-was examined on E. coli at 37 "C suspended in ammonium-salts glucose medium (Reiter et a/., 1976) and on S. lactis at 30°C suspended in the synthetic medium of Reiter & Oram (1962) from which cysteinelwas omitted. Both media were adjusted to pH 5.5 for better comparison with activity of the LP system (Reiter et a/., 1976).…”

Human Milk and Breast Feeding: an Update on the State of the Art

“…These include immunocompetent T and B lymphocytes, polymorphonuclear leukocytes, macrophages (27)(28)(29), immunoglobulins, especially secretory IgA (29,30), and components of complement system (25,31,32). Additional soluble factors which are active against streptococci, staphylococci and tumor viruses (33)(34)(35) have also been identified. Of these components, the developmental characteristics of secretory IgA in the human colostrum and milk have been studied most extensively.…”

A polyol mixture or molasses treated beet pulp in the silage based diet of dairy cows: II. The effect on the lactoperoxidase and thiocyanate content of milk and the udder health

“…A stabilization period of two weeks preceded the 12-week experimental phase. More detailed information about the animals and the experimental design has been given in a previous paper (Tuori and Poutiainen 1977 Oram and Reiter (1966 a): 3 ml of phosphate buffer (0.1 M, pH 6.7), which contained 0.01 % o-dianisidine (Sigma Chemical Co., St. Louis, Mo. ), was pipetted into a glass cuvette (1 cm).…”

“…The inhibitory system catalyzed by LP requires the presence of hydrogen peroxide and thiocyanate or some other oxidigable substance (halides) (Reiter et al 1964, Oram and Reiter 1966a, b, Klebanoff et al 1966). This system is nonspecifically bactericidal or bacteriostatic and it has been found to affect numerous gram-positive and gram-negative saprophytic and pathogenic bacteria (Reiter et al 1964, Klebanoff et al 1966, Mickelson 1966, Klebanoff 1967, Hamon and Klebanoff 1973, Hoogendoorn and Moore,r 1973, Reiter et al 1976).…”