Post-slaughter changes in ATP metabolites,reducing and phosphorylated sugars in chicken meat

The formation of ATP breakdown products in chicken M. pectoralis major post-slaughter is reported. The concentrations of metabolites were followed in chicken breast throughout the carcass processing post-slaughter and during chilled storage. The concentration of glucose remains similar throughout the period whilst that of glucose-6-phosphate decreases linearly. Glucose and glucose-6-phosphate concentrations were inversely related to the pHu of the breast meat throughout chilled storage. Rapid post-mortem glycolysis and high pHu values suggest the occurrence of stress at and pre-slaughter. Whilst ATP, ADP and AMP were rapidly broken down, the concentration of IMP rose rapidly and remained high. Concentrations of inosine, ribose and hypoxanthine increased gradually post-slaughter but an initial increase in ribose phosphate was not sustained. Most of the potential ribose present in chicken meat, believed to be important for flavor formation, remains bound in the form of inosine and IMP. There is evidence that additional breakdown pathways for ribose and ribose-5-phosphate may deplete the concentrations of these precursors.     

Trans-Cinnamic Acid Increases Adiponectin and the Phosphorylation of AMP-Activated Protein Kinase through G-Protein-Coupled Receptor Signaling in 3T3-L1 Adipocytes

Adiponectin and intracellular 5′adenosine monophosphate-activated protein kinase (AMPK) are important modulators of glucose and fat metabolism. Cinnamon exerts beneficial effects by improving insulin sensitivity and blood lipids, e.g., through increasing adiponectin concentrations and AMPK activation. The underlying mechanism is unknown. The G_i/G_o-protein-coupled receptor (GPR) 109A stimulates adiponectin secretion after binding its ligand niacin. Trans-cinnamic acid (tCA), a compound of cinnamon is another ligand. We hypothesize whether AMPK activation and adiponectin secretion by tCA is transmitted by GPR signaling. Differentiated 3T3-L1 cells were incubated with pertussis toxin (PTX), an inhibitor of G_i/G_o-protein-coupling, and treated with different tCA concentrations. Treatment with tCA increased adiponectin and the pAMPK/AMPK ratio (p ≤ 0.001). PTX incubation abolished the increased pAMPK/AMPK ratio and adiponectin secretion. The latter remained increased compared to controls (p ≤ 0.002). tCA treatment stimulated adiponectin secretion and AMPK activation; the inhibitory effect of PTX suggests GPR is involved in tCA stimulated signaling.     

环磷腺苷葡胺后处理对大鼠心肌缺血再灌注损伤的保护作用

目的观察环磷腺苷葡胺（MCA）对大鼠心肌缺血再灌注损伤的保护作用。方法40只大鼠按随机数字表法分为空白对照组、缺血再灌注损伤组（I／R组）、缺血后处理组（IPO组）和MCA后处理组（MCA组）,每组10只。空白对照组仅行左冠状动脉左前降支套线而不阻断150min,I／R组阻断30min、再灌注120min,IPO组在再灌注初短暂缺血10S,再灌注10S、反复6次、处理后同I／R组,MCA组在再灌注前10min经静脉给予环磷腺苷葡胺注射液5mg·kg-1,其他处理同I／R组。再灌注120min后,测各组血清SOD活性及血清MDA含量、心肌ATP酶活性和心肌细胞凋亡指数（AI）,电镜下观察细胞超微结构变化。结果与I／R组比,IPO组和MCA组血清SOD活性增高,血清MDA含量降低,ATP酶活性增高,AI减少显著,细胞结构损伤减轻。结论MCA对心肌缺血再灌注损伤具有保护作用,其机制可能与改善能量代谢障碍有关。     

Evaluation of anti-wrinkle efficacy of adenosine-containing products using the FOITS technique

The objective of this study was to evaluate formulations containing adenosine to reduce periorbital lines and glabellar frowns in a blind, randomised, placebo-controlled study. One hundred twenty-six female volunteers between 45 and 65 years of age fulfilled inclusion criteria for periorbital lines. They were provided with two of three products (cream with adenosine, dissolvable film with adenosine or placebo), to be applied to the periorbital area on each side of the face (84 subjects per product). Eighty-four of these subjects also fulfilled the inclusion criteria for glabellar frowns, and received placebo or cream with adenosine to be applied to the glabellar area. Products were applied twice daily for 2 months, and evaluation was performed under dermatological supervision at 0, 3 and 8 weeks using Fast Optical in vivo Topometry of human Skin (FOITS) analysis to describe skin profile. Both adenosine-containing products led to significant improvements in skin smoothness in the periorbital area. Improvements were evidenced after 3 weeks of product application as measured by Ra and Rz parameters using the FOITS technique, and were steadily confirmed after 2 months, despite severe climatic conditions and independently of the analysis technique that was used with the FOITS data. Adenosine-containing cream also significantly improved glabellar frowns. This study demonstrates the potential beneficial effects of adenosine-containing products on crow's feet and glabellar facial wrinkles.     

Interactions between saporin, a ribosome-inactivating protein, and DNA: a study by atomic force microscopy

Saporins are enzymes belonging to the PNAG class (polynucleotide: adenosine glycosidase), plant enzymes commonly known as ribosome-inactivating proteins (RIP), as a result of their property of irreversibly damaging eukaryotic ribosomes. Direct imaging with tapping-mode atomic force microscopy (AFM) has been used to study pGEM-4Z plasmid DNA binding to the saporin-SO6 (isoform from Saponaria officinalis seeds). Saporin wrapped the plasmidic DNA, and distribution of the enzyme molecules along the DNA chain was markedly variable; plasmid digested with saporin-SO6 appeared fragmented or topologically modified. The supercoiled DNA strands were cleaved, giving rise to a linearized form and to relaxed forms. Electrophoretic analysis of the effect of standard preparations of saporin-SO6 on pGEM-4S confirmed the presence of DNA strand-cleaving activity.     

高效液相色谱法测定马齿苋中腺苷的含量

目的建立高效液相色谱法检测分析马齿苋中腺苷含量的分析方法。方法比较纯水、不同体积分数的乙醇、不同体积分数的甲醇为提取溶剂时,马齿苋中腺苷提取量差异,优选最佳的提取方式。采用安捷伦ZORBAX SB-Aq色谱柱(4.6 mm×250 mm, 5μm),以乙腈:0.1%乙酸=7:93(V/V)为流动相,流速0.5 mL/min,检测波长260 nm,柱温40℃,对马齿苋中的腺苷进行测定。结果纯水提取得到的腺苷含量高于不同体积分数的乙醇和甲醇提取。腺苷在1.71～171.0mg/L范围内线性关系良好,相关系数r~2=0.9999,加样平均回收率为92.65%。结论该方法结果可靠,操作简单,可以准确的测定马齿苋中的腺苷含量,可以作为马齿苋质量控制的方法之一。     

过表达嘌呤合成途径关键酶基因对重组酿酒酵母菌株生产cAMP的影响

研究了环磷酸腺苷(cAMP)合成途径中的3个关键酶基因(磷酸核糖焦磷酸合成酶基因PRS1和PRS3、磷酸核糖焦磷酸氨基转移酶基因ADE4、腺苷酸激酶基因ADK1)过量表达对重组酿酒酵母(Saccharomyces cerevisiae)发酵向胞外分泌cAMP的影响,利用酿酒酵母游离型质粒YEplac195和磷酸甘油酸激酶PGK的强启动子PGK1p及终止子PGK1t构建含PRS1, PRS3, ADE4和ADK1的单基因表达载体,分别转入cAMP生产菌GA125,通过摇瓶发酵实验考察重组菌株与对照菌株的生长、cAMP生产及胞外腺嘌呤消耗情况. 结果表明,在外加腺嘌呤条件下,与对照菌株相比,PRS1, PRS3和ADE4基因过表达菌株的cAMP产量分别提高4.17%, 9.03%和6.06%,而ADK1过表达菌株的cAMP产量降低3.85%.     

虫草菌丝体中腺苷和虫草素的定性分析

介绍了虫草菌素的生物活性;对比了虫草菌素与腺苷的3种定性分析方法,其中薄层层析和高效液相色谱法可行。检测结果表明待测的古尼拟青霉519样品中含有腺苷,蛹草拟青霉菌丝体中含有虫草菌素。     

金属离子对面包酵母合成ATP的影响机制初探

对Mg2+, K+和Na+在面包酵母酶系合成ATP过程中的影响机制进行了初步研究. 发现Mg2+对ATP的合成影响很大,当Mg2+浓度为40 mmol/L时,ATP合成量达到最大值,为6.07 mmol/L;高浓度磷酸钾缓冲液会抑制ATP的合成,进一步研究发现高浓度K+对ATP合成具有明显抑制作用,但K+完全缺乏时,也不利于腺苷的转化;Na+可通过激活腺苷酸激酶的活性来促进ATP合成,同时激活腺苷脱氨酶的活性,其存在会使底物腺苷向肌苷转化.