Reactions of proteins with oxidizing lipids: 1. Analytical measurements of lipid oxidation and of amino acid losses in a whey protein-methyl linolenate model system

1. The reactions between protein-bound amino acids and oxidizing lipid were investigated in a whey protein-methyl linolenate (C18.3)-water model system. The extent of fat oxidation was followed by measuring oxygen uptake, hydroperoxide formation and hydrocarbon (ethane and pentane) formation. 2. Significant losses occurred with lysine (up to 71 %), tryptophan (up to 31 %) and histidine (up to 57%). Methionine was extensively oxidized to its sulphoxide but less than 2% was further oxidized to the sulphone. No other amino acids were affected. 3. Increasing storage temperature (20°, 37°, 55°) resulted in an enhancement of fat oxidation reactions and amino acid degradation. 4. Increasing water activity (0.28, 0.65, 0.90) increased losses of lysine and tryptophan but had no influence on the oxidation of methionine, the level of remaining hydroperoxides or 02 uptake. Hydrocarbons were decreased. 5. Limitation of 02 uptake to 1 mol/mol lipid instead of excess 02 (02 uptake about 2.5 mol/mol lipid in 4 weeks) significantly reduced the degradation of lysine and tryptophan but had less influence on the oxidation of methionine. The level of remaining hydroperoxides was increased but hydrocarbons were unaffecte

Novel Calicivirus Identified in Rabbits, Michigan, USA

This virus is distinct from rabbit hemorrhagic disease virus

A headspace solid-phase microextraction method of use in monitoring hexanal and pentane during storage: Application to liquid infant foods and powdered infant formulas

The determination of two secondary lipid oxidation compounds (hexanal and pentane) in liquid infant foods using a headspace solid-phase microextraction gas chromatographic (HS-SPME-GC) method has been developed and validated. The HS-SPME analytical conditions (fibre position, equilibration and sampling times) were selected. The analytical parameters of the method (linearity: hexanal from 2.48 to 84.78 ng/g, pentane from 6.21 to 79.55 ng/g; precision: hexanal 2.87%, pentane 2.343.46%; recovery: hexanal 106.60%, pentane 95.39%; detection limit: hexanal 3.63 ng and pentane 4.2 ng) demonstrate the usefulness of the method. Once optimized, the method was applied to liquid infant foods based on milk and cereals, and to powdered adapted and follow-up milk-based infant formulas (IF), stored for four and seven months. In all cases the hexanal content was higher in IF than in milk-cereal based infant foods. No pentane was found in IF

Memory CD8+ T Cells Balance Pro- and Anti-inflammatory Activity by Reprogramming Cellular Acetate Handling at Sites of Infection.

Serum acetate increases upon systemic infection. Acutely, assimilation of acetate expands the capacity of memory CD8+ T cells to produce IFN-γ. Whether acetate modulates memory CD8+ T cell metabolism and function during pathogen re-encounter remains unexplored. Here we show that at sites of infection, high acetate concentrations are being reached, yet memory CD8+ T cells shut down the acetate assimilating enzymes ACSS1 and ACSS2. Acetate, being thus largely excluded from incorporation into cellular metabolic pathways, now had different effects, namely (1) directly activating glutaminase, thereby augmenting glutaminolysis, cellular respiration, and survival, and (2) suppressing TCR-triggered calcium flux, and consequently cell activation and effector cell function. In vivo, high acetate abundance at sites of infection improved pathogen clearance while reducing immunopathology. This indicates that, during different stages of the immune response, the same metabolite-acetate-induces distinct immunometabolic programs within the same cell type

Metabolic and non-metabolic roles of PHGDH and their impact on T cell function

Cell-intrinsic metabolism underpins T cell differentiation and function. Metabolic enzymes can, however, also engage in non-metabolic (moonlighting) roles – which creates potential for functional incompatibilities. For the rate limiting enzyme in serine synthesis, PHGDH, we here describe a paradigm of such an incompatibility, demonstrating how, and at what price, metabolic function is traded off to block moonlighting during CD8+ T cell differentiation. Complete serine restriction of CD8+ T cells triggered an extensive stress response orchestrated by a coordination of p53 and Myc – highlighting the importance of serine for T cells. Surprisingly therefore, PHGDH was only expressed in naïve but not memory CD8+ T cells, causing memory-selective serine auxotrophy and immunodeficiency in serine deplete hosts. Silencing of PHGDH was, however, a requirement for a normal naïve to memory transition to occur and, more broadly, a hallmark of differentiation across immune and non-immune cell lineages. Specific mutations in PHGDH, such as R163Q, are linked to differentiation-abnormalities and yet the R163Q variant showed near-normal enzymatic activity. This triggered a search for PHGDH moonlighting features, which identified PHGDH as RNA-binding protein (RBP) with affinity for cell-fate determining transcripts. Our data establish a trade-off between metabolic activity and moonlighting of PHGDH in differentiating T cells, highlighting the integrated evolution of complex cellular processes and expanding the conceptual framework when interpreting cellular metabolic phenotypes

OUTLINE OF RECOMMENDATIONS FOR APPROPRIATE DOMESTIC RABBIT MANAGEMENT IN ACCORDANCE WITH ANIMAL PROTECTION AND WELFARE CONSIDERATIONS

Abstract not available.Löliger, H. (1996). OUTLINE OF RECOMMENDATIONS FOR APPROPRIATE DOMESTIC RABBIT MANAGEMENT IN ACCORDANCE WITH ANIMAL PROTECTION AND WELFARE CONSIDERATIONS. World Rabbit Science. doi:10.4995/wrs.1996.279.SWORD04