Non-inhibitory levels of oxygen during cultivation increase freeze-drying stress tolerance in Limosilactobacillus reuteri DSM 17938.

The physiological effects of oxygen on Limosilactobacillus reuteri DSM 17938 during cultivation and the ensuing properties of the freeze-dried probiotic product was investigated. On-line flow cytometry and k-means clustering gating was used to follow growth and viability in real time during cultivation. The bacterium tolerated aeration at 500 mL/min, with a growth rate of 0.74 ± 0.13 h-1 which demonstrated that low levels of oxygen did not influence the growth kinetics of the bacterium. Modulation of the redox metabolism was, however, seen already at non-inhibitory oxygen levels by 1.5-fold higher production of acetate and 1.5-fold lower ethanol production. A significantly higher survival rate in the freeze-dried product was observed for cells cultivated in presence of oxygen compared to absence of oxygen (61.8% ± 2.4% vs. 11.5% ± 4.3%), coinciding with a higher degree of unsaturated fatty acids (UFA:SFA ratio of 10 for air sparged vs. 3.59 for N2 sparged conditions.). Oxygen also resulted in improved bile tolerance and boosted 5'nucleotidase activity (370 U/L vs. 240 U/L in N2 sparged conditions) but lower tolerance to acidic conditions compared bacteria grown under complete anaerobic conditions which survived up to 90 min of exposure at pH 2. Overall, our results indicate the controlled supply of oxygen during production may be used as means for probiotic activity optimization of L. reuteri DSM 17938.

Temperature and Heat Transfer Control During Freeze Drying. Effect of Vial Holders and Influence of Pressure.

OBJECTIVE: A common issue of freeze drying is the inhomogeneity between samples, both in regards to water content and structure. The purpose of this study is to address this issue, and try to understand the cause of inhomogeneity in the heat transfer and sample temperature. METHODS: The temperature and the heat transfer was measured using different setups, both with and without vial holders at various positions at different shelf temperature and chamber pressures. By comparing sublimation rate measurements (water sample) with temperature equilibrium measurements with a non-evaporating liquid (oil sample), the heat transfer contribution from radiation and conduction could be separated and investigated individually. RESULTS: The oil sample temperature increases each time the pressure is decreased; the increase is highest at lower shelf temperatures. Using vial holder reduces the deviation between the samples but have limited effect on the temperature increase. The sublimation rate for water sample is pressure dependent and samples close to the walls have a higher sublimation rate than vials in the center. The sublimation rate increases slightly when using a vial holder but the deviation between vials becomes more random. CONCLUSIONS: The heat transfer consists of conduction through rectified vapor and radiation from surrounding walls, about 65-75% of the heat is transferred by conduction and 25-35% by radiation under normal operational conditions. As the vial holder is also influenced by the radiation, the vial inside the holder is indirectly affected by the surrounding radiation.

Dependence of adrenoceptor regulation on oxidative stress in cardiac inju-ry induced by high sympathetic activity in rats / 中国病理生理杂志

AIM:To investigate the dependence of the adrenoceptor regulation on oxidative stress in the rats with cardiac injury induced by high sympathetic activity .METHODS: Healthy SD rats were randomly divided into 7 groups:control, model, propranolol (Pro), prazosin (Praz), Pro+Praz, vitamin E (VE) and Pro+Praz+VE.The rats were intraperitoneally injected with norepinephrine ( NE) for continuous 16 d to reproduce cardiac injury , and treated with the respective drugs .During the experimental process , the body weight was recorded .At the end of the experiments , the following parameters were measured:the ventricular remodeling indexes ( cardiac index and hydroxyproline of the left ven-tricle), histopathologic examination , oxidative/antioxidative indexes [MDA, SOD, catalase (CAT), GSH-Px and total an-tioxidant capacity (T-AOC)], and energy metabolism (Na+-K+ATPase and Ca2+-Mg2+ATPase).RESULTS: The in-crease of body weight in model group was significantly slower than that in control group after 9 d of treatment (P<0.05). The cardiac index and left ventricular hypertrophy were significantly increased .Oxidation/antioxidation and energy metabo-lism were disturbed.In Pro, Praz, Pro+Praz and VE groups, the body weight, cardiac index, left ventricular fibrosis and oxidative/antioxidative dysfunction were ameliorated .Pro, Praz and Pro +Praz increased the activity of Na +-K+ATPase and Ca2+-Mg2+ATPase.Treatment with Pro+Praz showed the best result in all of the indexes (P<0.05).CONCLU-SION:The dependence of adrenoceptor regulation plays an important role in the formation of oxidative stress in the process of rat cardiac injury induced by high sympathetic activity .

Effect and mechanism of Jianguguben capsule on osteoporosis induced by retinoic acid in rats / 中华中医药杂志

objective:To investigate the effect and mechanism of Jianguguben capsule on osteoporosis induced by retinoic acid in rats.Methods:The rats were given retinoic acid 75mg(kg/d)for 2 weeks by intragastric administration,at the same time treated with different drugs according to various groups consecutive for 4 weeks.The bone mine density(BMD)and bone mine capacity(BMC)were assayed by double energy X-ray bone-densitometry equipment,the blood was collected to assay the activity of StrACP in serum,and the hydroxyproline(HOP)contents of femur by commercial kits,the bone’s biomechanics of femur were detected.Results:Jianguguben capsule could significantly improve the bone’s biomechanics,increase the BMD, BMC,index of dry femur’weight,the contents of HOP in femur significantly,and remarkable decrease the level of StrACP in serum of the osteoporotic rats induced by retinoic acid.Conclusion:Jiangguguben capsule has anti-osteoporotic effect on osteoporotic rats induced by retinoic acid.