鱼体初始中心温度对智利竹筴鱼冷藏品质的影响

为了分析不同鱼体初始中心温度对冷藏智利竹筴鱼品质的影响,本文研究了初始中心温度为0、3和6℃的智利竹筴鱼(各处理依次标记为A、B和C)在4±1℃贮藏条件下的鱼体pH值、挥发性盐基氮(TVB-N)、三甲胺(TMA-N)、硫代巴比妥酸值(TBARS)和感官品质的变化规律。结果显示,在贮藏期间,各预处理竹筴鱼鱼体的pH值、TVB-N、TMA-N和TBARS均随着冷藏时间的延长而上升,且C组至第6 d时,其pH值、TVB-N、TMA-N和TBARS分别达到6.13、0.29 mg/g、0.13 mg/g、7.12 mg/kg,显著高于A、B组的结果(p0.05)。此外,竹筴鱼的感官评分与贮藏时间存在负相关性,且鱼体初始中心温度越低,其感官评分下降得越慢。研究表明,智利竹筴鱼鱼体初始中心温度越低,越有利于延缓鱼体各个鲜度指标的下降,从而保证竹筴鱼的冷藏品质,延长其货架期。     

替米沙坦在动脉粥样硬化中对肠道菌群及其代谢产物TMAO的影响

目的：探讨替米沙坦在动脉粥样硬化中对肠道菌群及代谢产物氧化三甲胺（trimethylamine N-Oxide, TMAO）的影响。方法：将17只ApoE-/-小鼠随机分为两组：对照组（Control, CTL）（n=8）和替米沙坦（10 mg·kg-1·d-1,灌胃）治疗组（telmisartan, TLM）（n=9）。喂食高脂饮食12周,3%水合氯醛麻醉处死,从眶后窦处采集静脉血,用高效液相色谱-串联质谱法检测TMAO,油红“O”染色法测量主动脉根部斑块的面积,免疫组化法检测斑块内白细胞介素-6（IL-6）、单核细胞趋化蛋白1（MCP-1）和巨噬细胞表面因子（mac-3）,留取结肠粪便进行肠道菌群16S-rRNA,V3-V4区测序。结果：与CTL组相比,TLM组的主动脉根部斑块面积明显减少,炎性因子IL-6、MCP-1和mac-3表达水平下降、血浆TMAO水平明显降低;肠道菌群功能差异分析提示两组小鼠在细胞转运及代谢、能量与转换、信号转导等方面具有统计学差异（P<0.05）,丰度差异分析提示TLM组较CTL组产生TMAO的肠道菌群（Anaeroplasmataceae, Bacteroidaceae, Clostridiaceae, Lachnospiraceae, Ruminococcaceae, Proteus）明显减少。结论：替米沙坦减轻动脉粥样硬化的机制除与阻断血管紧张素II 1型受体（AT1R）有关外,还可能与改变肠道菌群组成使得TMAO血浆含量减少有关。     

废水中甲胺类和甲醇含量的测定

建立了用气相色谱法测定废水中一、二、三甲胺和甲醇的分析方法,各组分离较好,水样不需处理,直接进样,测定的相对标准偏差≤6．4％,方法满足环境监测的要求。     

The Role of Gut Microbiota on Cholesterol Metabolism in Atherosclerosis

Hypercholesterolemia plays a causal role in the development of atherosclerosis and is one of the main risk factors for cardiovascular disease (CVD), the leading cause of death worldwide especially in developed countries. Current data show that the role of microbiota extends beyond digestion by being implicated in several metabolic and inflammatory processes linked to several diseases including CVD. Studies have reported associations between bacterial metabolites and hypercholesterolemia. However, such associations remain poorly investigated and characterized. In this review, the mechanisms of microbial derived metabolites such as primary and secondary bile acids (BAs), trimethylamine N-oxide (TMAO), and short-chain fatty acids (SCFAs) will be explored in the context of cholesterol metabolism. These metabolites play critical roles in maintaining cardiovascular health and if dysregulated can potentially contribute to CVD. They can be modulated via nutritional and pharmacological interventions such as statins, prebiotics, and probiotics. However, the mechanisms behind these interactions also remain unclear, and mechanistic insights into their impact will be provided. Therefore, the objectives of this paper are to present current knowledge on potential mechanisms whereby microbial metabolites regulate cholesterol homeostasis and to discuss the feasibility of modulating intestinal microbes and metabolites as a novel therapeutic for hypercholesterolemia.     

Shelf Life and Clostridium botulinum Toxin Development during Storage of Modified Atmosphere-packaged Fresh Catfish Fillets

Shelf life (onset of sensory spoilage) and potential for toxin production by Clostridium botulinum type E in retail type packages of fresh catfish fillets in high barrier film were investigated under selected atmospheres when stored under refrigeration and temperature-abuse conditions. Shelf life of fillets in all atmospheres decreased with increase of storage temperature from 4°C to 16°C. Trimethylamine content associated with onset of spoilage was different for each storage temperature and atmosphere. Surface pH and K-values were not good indicators of onset of sensory spoilage. Toxin development coincided with sensory spoilage at 16°C storage for fillets packaged in either atmosphere. At 4°C, none of the MA-packaged fillets became toxic, even after 37 days of sensory spoilage.     

三甲胺测定方法的研究进展

介绍了三甲胺的理化性质、用途和特点,概述了三甲胺测定的应用范围及测定方法,并提出了测定三甲胺方法的发展方向。     

基于三甲胺/氧化三甲胺物质的量比值动力学模型预测带鱼粉的货架期

以三甲胺（trimethylamine,TMA）/氧化三甲胺（trimethylamine oxide,TMAO）物质的量比值为带鱼粉 的品质变化和货架期的指示指标,根据感官评定结果,确定TMA/TMAO物质的量比值0.406 4为货架期终点。建立带 鱼粉的TMA/TMAO物质的量比值与贮藏时间（t）之间的一级动力学方程以及TMA/TMAO物质的量比值变化速率常 数（k）与贮藏温度（T）之间的Arrhenius方程,以预测某一贮藏温度下带鱼粉的货架期理论值。结果表明：Arrhenius 方程中TMA/TMAO物质的量比值变化反应的活化能Ea为3.77 kJ/mol,指前因子k0为10.11,带鱼粉的TMA/TMAO 物质的量比值的货架期预测模型为     

超声条件下新型醚化剂环氧丙基三甲基氯化铵（GTA）的合成与表征

环氧丙基三甲基氯化铵（GTA）是新型高效醚化剂,可改性聚合物,制备阳离子聚合物,用途广泛。本文以三甲胺与环氧氯丙烷（EPIC）超声条件下反应合成GTA。实验得出GTA的最佳合成条件为：n（TMA）∶n（EPIC）=0.25,反应时间为1.5 h,反应温度为25℃,最佳溶剂为丙酮,GTA的产率为96.57%,熔点为138~139℃。通过元素分析和红外光谱对GTA进行了结构表征。     

6种水产动物中氧化三甲胺的提取与含量测定

分别用溶剂抽提法和乙醇去蛋白法对6种水产动物中的氧化三甲胺进行了提取,并用雷氏盐比色法和苦味酸比色法进行含量测定。结果发现提取方法中用三氯乙酸作为溶剂的抽提法的提取率最高;含量测定法中雷氏盐法受同类物质干扰较大,测定结果偏高,不能反映样品的真实值。以三氯乙酸作为溶剂提取氧化三甲胺,苦味酸比色法测定其含量比较6种水产动物中氧化三甲胺含量,结果表明鲜贝含量最高,为0.128mg/g,胖头鱼含量最低,为0.063mg/g。