The effect of alveolar oxygen tension on lung lipid peroxidation during lung ischemia was evaluated by using isolated rat lungs perfused with synthetic medium. After a 5-min equilibration period, global ischemia was produced by discontinuing perfusion while ventilation continued with gas mixtures containing 5% CO2 and a fixed oxygen concentration between 0 and 95%. Lipid peroxidation was assessed by measurement of tissue thiobarbituric acid-reactive products and conjugated dienes. Control studies (no ischemia) showed no change in parameters of lipid peroxidation during 1 h of perfusion and ventilation with 20% or 95% 02. With 60 min of ischemia, there was increased lipid peroxidation which varied with oxygen content of the ventilating gas and was markedly inhibited by ventilation with N2. Perfusion with 5-, 8-, 11-, 14-eicosatetraynoic acid indicated that generation of eicosanoids during ischemia accounted for -40-50% of lung lipid peroxide production. Changes of CO2 content of the ventilating gas (to alter tissue pH) or of perfusate glucose concentration had no effect on lipid peroxidation during ischemia, but perfusion at 8% of the normal flow rate prevented lipid peroxidation. Lung dry/wet weight measured after 3 min of reperfusion showed good correlation between lung fluid accumulation and lipid peroxidation. These results indicate that reperfusion is not necessary for lipid peroxidation with ischemic insult of the lung and provide evidence that elevated Po2 during ischemia accelerates the rate of tissue injury. (J. Clin. Invest. 1991. 88:674479.)

Free fatty acids (FFAs) in plasma are essential substrates for de novo synthesis of milk fat, or directly import into mammary cells. The physico-chemical properties of mammary cells membrane composition affected by FFAs with different chain lengths and saturability are unclear yet. Employing GC, FTIR and fluorescence spectroscopy, the adsorption capacity, phospholipids content, membrane proteins conformation, lipid peroxidation product, and free sulfhydryl of plasma membranes (PMs) interacted with different FFAs were determined. The mammary cells PMs at 38 and 39.5 °C showed different adsorption capacities: acetic acid (Ac) > stearic acid (SA) > β-hydroxybutyric acid (BHBA) > trans10, cis12 CLA. In the FTIR spectrum, the major adsorption peaks appeared at 2920 and 2850 cm for phospholipids, and at 1628 and 1560 cm for membrane proteins. The intensities of PMs-FFAs complexes were varied with the FFAs species and their initial concentrations. The β-sheet and turn structures of membrane proteins were transferred into random coil and α-helix after BHBA, SA and trans10, cis12 CLA treatments compared with Ac treatment. The quenching effects on the fluorescence of endogenous membrane protein, 1, 8-ANS, NBD-PE, and DHPE entrapped in PMs by LCFA were different from those of short chain FFAs. These results indicate that the adsorption of FFAs could change membrane protein conformation and polarity of head group in phospholipids. This variation of the mammary cells PMs was regulated by carbon chain length and saturability of FFAs.

The present communication introduces a new classification model for fatty acids (FA) distribution networks in ruminal microbe membrane based on experimental and computational studies. In the experimental part, long chain fatty acids and volatile fatty acids in ruminal microbe membrane or liquid phase were investigated by supplementation of different ratios of Omega-6 / Omega-3 and in the processes of base-/ acid-methylation. In the computational part, Perturbation Theory (PT) and Linear Free-Energy Relationships (LFER), combined with corresponding Box-Jenkins (ΔVkj) and PT Operators (ΔΔVkj) were applied into the calculation of physicochemical parameters (Vk) of fatty acids. The best PT-LFER model found to predict the effects of perturbations over the FA distribution network with Sensitivity, Specificity, and Accuracy > 80% for 407,655 cases. In final, PT-LFER model based on LDA was used to reconstruct the complex networks of perturbations in the FA distribution and compared with random Erdős-Ré nyi network models. The detail results have been published in Mol. BioSyst., 2015, Aug., the present is a short communications.

The cover image, by Xiumin Zhang et al., is based on the Research Article Urea plus nitrate pretreatment of rice and wheat straws enhances degradation and reduces methane production in in vitro ruminal culture, DOI: https://doi.org/10.1002/jsfa.9056.