Taurine prevents tissue damage in a variety of models that involve inflammation, including oxidant-induced lung damage. The mechanism of protection is uncertain, but is postulated to involve the actions of taurine chloramine (Tau-Cl) derived via halide-dependent myeloperoxidase associated with neutrophils. Understanding the influence of Tau-Cl on the production of inflammatory mediators by alveolar macrophages provides an opportunity for determining the mechanism of Tau-Cl action. The effects of Tau-Cl were evaluated on the production of NO and TNF-α in NR8383, a cloned cell line derived from rat alveolar macrophages (RAM), and in primary cultures of RAM. Production of NO and TNF-α, and expression of inducible NO synthase was inhibited by Tau-Cl in activated NR8383 cells as well as in RAM. Temporal (2, 4, 8, 24 h) expression of inducible NO synthase and TNF-α mRNAs was reduced by Tau-Cl in NR8383 cells. Tau-Cl depressed NF-κB migration into the nucleus of activated NR8383 cells and caused a more sustained presence of IκB in the cytoplasm. Stabilization of cytoplasmic IκB-α in Tau-Cl-treated cells resulted from decreased phosphorylation of IκB-α serine-32 and a lower activity of IκB kinase (IKK). Additional experiments demonstrated that Tau-Cl does not directly inhibit IKK activity. These results suggest that Tau-Cl exerts its effects at some level upstream of IKK in the signaling pathway and inhibits production of inflammatory mediators through a mechanism that, at least in part, involves inhibition of NF-κB activation.

BEUCHAT, CHERRY, QUI" egg white was due to heat denaturation of the ovomucinlysozyme complex. In general, foam persistence is the result of the interaction of several factors, including surface tension, viscosity, temperature, pH, ionic strength, and concentration of protein in solution (Briskey, 1968; Hansen and Black, 1972).All yeast protein isolates except those prepared by heat precipitation at pH 6.0 from alkaline extracts showed good emulsifying activity and were slightly superior than soy isolate. The yeast protein isolates prepared from water extracts and precipitated with heat possessed lower emulsifying activity than the samples precipitated without heat. Lawhon and Cater (1971) also found that some functional properties of protein isolates from glandless cottonseed processed with heat were inferior to those of isolates from unheated meal.The yeast proteins lowered the surface tension of aqueous solutions. However, they were not as effective as soy isolates in this respect. This property was reflected in the lower foam stability of the yeast protein isolates compared to soy isolate.Yeast protein isolates, especially those obtained by water extraction (Vananuvat and Kinsella, 1975b, 1975c) which are low in nucleic acids and have a good amino acid balance, should have potential commercial application in meat emulsions, ground meats, and bakery goods. These isolates possess a light creamy color, little flavor, and good emulsifying properties.

Taurine is present in high concentrations in most mammalian tissues, including those that prodigiously produce oxidants. Taurine protects against bronchiolar damage induced by NO2, ozone, bleomycin, and amiodarone. Taurine is chlorinated to form taurine chloramine (Tau-Cl) by the halide-dependent myeloperoxidase system and, under physiological conditions, reduces HOCl toxicity. Although NO and its metabolites, NO2- and NO3-, are thought to be major mediators of tissue damage resulting from oxidant exposure, cytokines, including tumor necrosis factor (TNF), are also involved. We examined the effects of Tau-Cl on NO production and TNF release by using RAW 264.7 cells activated with recombinant interferon-gamma (rIFN-gamma; 50 U/ml) and lipopolysaccharide (LPS; 10 micrograms/ml). NO was measured spectrophotometrically as NO2- after reaction with Griess reagent and TNF was measured by ELISA. Tau-Cl (0.5 mM) inhibits NO and TNF released into the medium by 47% and 43%, respectively. Tau-Cl is actively transported into RAW 264.7 cells by an uptake system that is energy, temperature, and Na+ dependent. Competition experiments demonstrate that the uptake system for Tau-Cl is distinct from that for taurine. In addition, the NO synthase activity of cytosolic preparations from activated RAW 264.7 cells is irreversibly inhibited by pretreatment with Tau-Cl. We demonstrate that Tau-Cl inhibits production of NO and TNF by activated macrophages and suggest a mechanism through which taurine supplementation may protect against oxidant-induced tissue damage.

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