Effects of dietary anthocyanins on tocopherols and lipids in rats

The effects of dietary cyanidin-3-O-glucoside (C3G) and concentrates from blackcurrant [Ribes nigrum] (BC) and elderberry [Sambucus nigra] (EC) on plasma and tissue concentrations of alpha- (alpha-T) and gamma-tocopherol (gamma-T) and cholesterol, as well as the fatty acid composition of the liver lipids were investigated in growing, male rats of the Sprague-Dawley strain. Animals were fed semisynthetic diets supplemented with 2 g/kg C3G, BC, or EC for 4 weeks. Dietary anthocyanins did not affect feed intake, body weight, and organ weights. C3G elevated the concentrations of tocopherols in the liver and lungs (P < 0.05). Cholesterol levels in plasma and liver were not affected by any of the regimens. C3G and BC reduced the relative amount of saturated fatty acids in the liver (P < 0.05). BC also lowered the percentage of 22:6 + 24:0 and EC the ratio of 20:3/20:4 n-6 (P < 0.05). In conclusion, dietary C3G, BC, and EC appear to have little effect on cholesterol levels and the fatty acid pattern in the liver but seem to be capable of sparing vitamin E in healthy, growing rats.     

热风干燥过程相对湿度对香菇品质的影响

为了研究干燥介质相对湿度对香菇品质的影响,该研究将计算机视觉在线检测技术应用于基于温湿度过程控制的热风干燥技术中,利用4种不同的相对湿度控制方法对去柄香菇进行干燥：连续排湿、全程设定恒定相对湿度（40%,30%,20%）、阶段降低相对湿度以及后期迅速降低相对湿度（30%优化,阶段降湿优化）。利用图像信息实时获取香菇外观品质,探究了香菇干燥过程中收缩率、圆度、表面褶皱率（Ratio of Wrinkled Surface Area,RWSA）与纹理特征（对比度、能量）的变化,并利用扫描电镜图像上香菇细胞的长宽比表示干香菇的微观结构,采用气相色谱-离子迁移谱联用（Gas Chromatography-ion Mobolity Spectrometry,GC-IMS）技术获取干香菇的风味成分。研究结果表明,相对湿度对香菇细胞的收缩率、圆度、纹理特征以及结构与复水比均有显著性影响（P < 0.05）,全程40%与全程20%组分别由于其相对湿度过高与维持时间过长,导致干燥时间延长,香菇表面硬化程度降低,收缩率增加,圆度降低,表面褶皱增多且更细密,表面颜色对比度降低,香菇表面褶皱率达到最大值的时间与香菇复水比呈正相关关系（r2 = 0.88）,香菇表面褶皱率达到最大值的时间越晚,香菇复水比越高,通过香菇褶皱率变化可预测香菇复水比。而优化组（30%优化、阶段降湿优化）可缩短干燥时间,加速香菇表面硬化,保持香菇外观品质,虽然其干制品复水比,微观结构与风味成分均不如连续排湿组,但其咀嚼度（P < 0.05）与弹性更高。综合考虑干燥时间与干香菇的品质,优先采用连续排湿,其次采用30%优化的方式干燥香菇。     

Ergosterol profiles, fatty acid composition, and antioxidant activities of button mushrooms as affected by tissue part and developmental stage

This article investigated the mycochemical profiles and the antioxidant activities of the lipophilic extracts of the white and brown button mushrooms. We found that only free ergosterols were present in both mushrooms at 2.04-4.82 mg/g dry matter (DM). Ergosterol concentration was higher in early growth stages but decreased as the mushrooms grew, and it distributed evenly between the caps and stems during early developmental stages but accumulated more in the caps after maturation. The photochemiluminescence (PCL) values of the two mushrooms were 5.49-10.48 nmol trolox equivalent/mg DM, and the EC50 values of 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay ranged 20.19-41.49 mg DM/μg DPPH. The ergosterol content positively correlated with the antioxidant activities (r2>0.89). The total fatty acid content was 8.7 mg/g DM in the white and 5.1 mg/g DM in the brown button mushroom and contained mainly linoleic, palmitic, and stearic acids. Our data provide guidance for optimized harvesting time of mushrooms and maximized health benefits.     

Hepatic gene expression of the insulin signaling pathway is altered by administration of persimmon peel extract: a DNA microarray study using type 2 diabetic Goto-Kakizaki rats

Persimmon (Diospyros kaki) is a very popular fruit in East Asian countries, but its peels are not consumed despite the fact that they contain many antioxidants such as carotenoids and polyphenols. We prepared a fat-soluble extract from persimmon peel (PP) and fed type 2 diabetic Goto-Kakizaki (GK) rats an AIN-93G rodent diet supplemented with persimmon peel extract (PP diet) for 12 weeks. Compared with the control AIN-93G diet, the PP diet significantly reduced plasma glutamic-pyruvate transaminase activity, with accumulation of β-cryptoxanthin in the liver. DNA microarray analysis revealed that the PP diet altered hepatic gene expression profiles. In particular, expression of insulin signaling pathway-related genes was significantly enriched in differentially expressed gene sets. Moreover, Western blotting analysis showed an increase in insulin receptor beta tyrosine phosphorylation in rats fed the PP diet. These data suggest that the PP diet improves insulin resistance in GK rats.     

Contents of vitamins, mineral elements, and some phenolic compounds in cultivated mushrooms

The aim of the study was to determine the contents of mineral elements (Ca, K, Mg, Na, P, Cu, Fe, Mn, Cd, Pb, and Se), vitamins (B(1), B(2), B(12), C, D, folates, and niacin), and certain phenolic compounds (flavonoids, lignans, and phenolic acids) in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinus edodes, and Pleurotus ostreatus. Selenium, toxic heavy metals (Cd, Pb), and other mineral elements were analyzed by ETAAS, ICP-MS, and ICP methods, respectively; vitamins were detected by microbiological methods (folates, niacin, and vitamin B(12)) or HPLC methods (other vitamins), and phenolic compounds were analyzed by HPLC (flavonoids) or GC--MS methods (lignans and phenolic acids). Cultivated mushrooms were found to be good sources of vitamin B(2), niacin, and folates, with contents varying in the ranges 1.8--5.1, 31--65, and 0.30--0.64 mg/100 g dry weight (dw), respectively. Compared with vegetables, mushrooms proved to be a good source of many mineral elements, e.g., the contents of K, P, Zn, and Cu varied in the ranges 26.7--47.3 g/kg, 8.7--13.9 g/kg, 47--92 mg/kg, and 5.2--35 mg/kg dw, respectively. A. bisporus/brown contained large amounts of Se (3.2 mg/kg dw) and the levels of Cd were quite high in L. edodes (1.2 mg/kg dw). No flavonoids or lignans were found in the mushrooms analyzed. In addition, the phenolic acid contents were very low.     

Effect of long-term dietary administration of oregano on the alleviation of carbon tetrachloride-induced oxidative stress in rats

This study aimed at evaluating the protective effect of long-term dietary oregano on the alleviation of carbon tetrachloride-induced oxidative stress in rats. Twenty-four female Wistar rats were allocated to four groups of six animals each. Groups 1 (control) and 2 (CCl 4) were fed a basal diet, while groups 3 (oregano) and 4 (oregano + CCl 4) were fed the basal diet supplemented further with ground oregano at 1% level. Following six-week feeding, the rats of groups 2 and 4 were given a single intraperitoneal injection of CCl 4 at a dose of 1 mL/kg bw. Six hours after the CCl 4 injection, all animals were sacrificed, and serum, liver, kidney, and heart tissue samples were collected. Analysis results showed that the addition of oregano significantly increased the total phenolic content and the Trolox equivalent antioxidant capacity of the basal diet but had no effect on its lipid peroxidation index. Treatment with CCl 4 of rats from the CCl 4 group caused a significant increase in aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) in serum, whereas it decreased cholesterol and triglyceride content as compared to the control. It also increased the lipid peroxidation index and decreased the scavenging activities of the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt (ABTS) radical cation, the hydroxyl anion radical, the superoxide anion radical, and the hydrogen peroxide in all tested tissues, as compared to that of the control. Without CCl 4 treatment, diet supplementation with oregano had no effect on these biochemical parameters, excluding the hydroxyl radical scavenging activity, which was increased in all tested tissues as compared to that of the control. Feeding oregano before CCl 4 treatment resulted in a significant decline of the increase in AST, ALT, and ALP activities ( P < 0.05 vs CCl 4 group), but the recorded values could not attain those of the control group ( P < 0.05 vs control group). It significantly increased the reduced cholesterol and triglycerides ( P < 0.05 vs CCl 4 group) to values not differing from those of the control. It also resulted in a significant reduction of the increased malondialdehyde ( P < 0.05 vs CCl 4 group) to values that could not attain the levels of the control but had no significant effect ( P > 0.05) on the reduced ABTS radical cation scavenging activity. It increased significantly the reduced hydroxyl anion radical scavenging activity ( P < 0.05 vs CCl 4 group) to values that could not attain those of the control in all tested tissues except kidney. Additionally, it resulted in a significant elevation of the decreased superoxide anion radical scavenging activity in serum and liver but had no effect in kidney and heart, whereas it also resulted in a significant elevation of the decreased hydrogen peroxide scavenging activity in liver, kidney, and heart but had no effect in serum. These results suggest that dietary oregano may effectively improve the impaired antioxidant status in CCl 4-induced toxicity in rats.     

The dietary hydroxycinnamate caffeic acid and its conjugate chlorogenic acid increase vitamin e and cholesterol concentrations in Sprague-Dawley rats

Vegetarian diets are correlated with a reduced risk of developing cardiovascular disease and comprise a great variety of bioactive compounds, including hydroxycinnamic acid derivatives. Therefore, this study aimed to identify dietary hydroxycinnamic acid derivatives that may alter two important factors related to the development of cardiovascular disease, namely, tocopherol (T) and cholesterol (C) concentrations in the body. The effects of caffeic acid (CA), chlorogenic acid (CGA), and ferulic acid (FA) on alpha-T, gamma-T, and C levels in blood plasma, liver, and lungs were investigated after these compounds had been fed to rats for 4 weeks at concentrations of 2 g/kg in semisynthetic diets. None of the regimens affected weight gain, feed intake, or absolute weights of livers and lungs, although CA increased the liver weight relative to the body weight (P < 0.05). CA- and CGA-fed animals showed a tendency toward sparing vitamin E in all tissues, but statistical significance was obtained only for gamma-T in the liver of CA-fed animals (P < 0.005) and for alpha-T in the lungs of CGA-treated rats (P < 0.05). CGA supplementation reduced concentrations of lipids in the lung tissue (P < 0.05). CA and CGA elevated the concentrations of C in liver tissue and lipids to a similar extent, but only CA decreased the ratio of high-density lipoprotein C to total C in blood plasma (P < 0.05 for all effects). Animals eating FA showed T and C values comparable to those in the control group. In conclusion, this study demonstrates that dietary caffeic and chlorogenic acid may elevate tocopherols and cholesterol in vivo.     

Lower weight gain and hepatic lipid content in hamsters fed high fat diets supplemented with white rice protein, brown rice protein, soy protein, and their hydrolysates

The physiological effects of the hydrolysates of white rice protein (WRP), brown rice protein (BRP), and soy protein (SP) hydrolyzed by the food grade enzyme, alcalase2.4 L, were compared to the original protein source. Male Syrian Golden hamsters were fed high-fat diets containing either 20% casein (control) or 20% extracted proteins or their hydrolysates as the protein source for 3 weeks. The brown rice protein hydrolysate (BRPH) diet group reduced weight gain 76% compared with the control. Animals fed the BRPH supplemented diet also had lower final body weight, liver weight, very low density lipoprotein cholesterol (VLDL-C), and liver cholesterol, and higher fecal fat and bile acid excretion than the control. Expression levels of hepatic genes for lipid oxidation, PPARα, ACOX1, and CPT1, were highest for hamsters fed the BRPH supplemented diet. Expression of CYP7A1, the gene regulating bile acid synthesis, was higher in all test groups. Expression of CYP51, a gene coding for an enzyme involved in cholesterol synthesis, was highest in the BRPH diet group. The results suggest that BRPH includes unique peptides that reduce weight gain and hepatic cholesterol synthesis.     

Characterization of phytase activity from cultivated edible mushrooms and their production substrates

Phytase is used commercially to maximize phytic acid degradation and to decrease phosphorus levels in poultry and swine manure. To determine phytase content in edible mushrooms, basidiomata of Agaricus bisporus and three specialty mushrooms (Grifola frondosa, Lentinula edodes, and Pleurotus cornucopiae) and spent mushroom substrate (SMS) were surveyed. Enzyme activity ranged from 0.046 to 0.074 unit/g of tissue for four A. bisporus types (closed and open whites and closed and open browns) grown at The Pennsylvania State University's Mushroom Test Demonstration Facility (MTDF). The addition of various nutrient supplements to phase II mushroom production substrate did not alter phytase activity in A. bisporus. Portabella mushrooms (open brown) obtained from a commercial farm had significantly higher levels of phytase activity (0.211 unit/g of tissue) compared to A. bisporus grown at the MTDF. Of the specialty mushrooms surveyed, maitake (G. frondosa) had 20% higher phytase activity (0.287 unit/g of tissue) than commercial portabella mushrooms. The yellow oyster mushroom (P. cornucopiae) ranked second in level of phytase activity (0.213 unit/g of tissue). Shiitake (L. edodes) contained the least amount of phytase in basidiomata (0.107 unit/g of tissue). Post-crop steam treatment (60 degrees C, 24 h) of SMS reduced phytase activity from 0.074 to 0.018 unit/g. Phytase was partially purified from commercially grown portabella basidiomata 314-fold with an estimated molecular mass of 531 kDa by gel filtration chromatography. The optimum pH for activity was 5.5, but appreciable phytase activity was observed over the range of pH 5.0-8.0. Partially purified A. bisporus phytase was inactivated following a 10-min incubation at > or =60 degrees C.     

Enzyme inactivation analysis for industrial blanching applications: comparison of microwave, conventional, and combination heat treatments on mushroom polyphenoloxidase activity.

Browning reactions in fruits and vegetables are a serious problem for the food industry. In mushrooms, the principal enzyme responsible for the browning reaction is polyphenoloxidase (PPO). Microwaves have recently been introduced as an alternative for the industrial blanching of mushrooms. However, the direct application of microwave energy to entire mushrooms is limited by the important temperature gradients generated within the samples during heating, which can produce internal water vaporization and associated damage to the mushrooms texture. A microwave applicator has been developed, whereby irradiation conditions can be regulated and the heating process monitored. Whole edible mushrooms (Agaricus bisporus) were blanched by conventional, microwave, and combined heating methods to optimize the rate of PPO inactivation. A combined microwave and hot-water bath treatment has achieved complete PPO inactivation in a short time. Both the loss of antioxidant content and the increase of browning were minor in the samples treated with this combined method when compared to the control. This reduction in processing time also decreased mushroom weight loss and shrinkage.     

Effects of dietary supplementation with cysteamine on growth hormone receptor and insulin-like growth factor system in finishing pigs

The present study was conducted to test the hypothesis that chronic cysteamine (CS) supplementation may affect serum insulin-like growth factor (IGF)-I concentrations and growth hormone (GH) receptor (GHR), IGF-I, IGF-I receptor (IGF-IR), IGF binding protein (IGFBP)-3, and insulin receptor (IR) mRNA levels in different tissues of finishing pigs. A total of 24 finishing pigs (60.05 +/- 1.24 kg; 12 gilts and 12 barrows) were assigned randomly to one of the three dietary groups, with four pens/group (per pen: one gilt, one barrow). The pigs were fed a basal diet containing 0 (control), 70, or 140 mg/kg cysteamine feed additive (containing 28% cysteamine hydrochloride) for 47 days. The results indicated that CS supplementation (70 mg/kg) increased the average daily gain (ADG) and serum IGF-I level, upregulated mRNA levels of GHR and IGF-I (liver, stomach, muscle), IGF-IR (stomach, duodenum, muscle), and IGFBP-3 (liver) but downregulated IGFBP-3 (stomach, duodenum, muscle). CS supplementation (70 mg/kg) did not affect mRNA levels of GHR and IGF-I (duodenum), IGF-IR (liver), and IR (liver, stomach, duodenum, muscle). CS supplementation (140 mg/kg) downregulated GHR (duodenum), IGF-I, and IGF-IR mRNA (liver, stomach, duodenum, muscle) but upregulated IGFBP-3 and IR mRNA (liver, stomach, duodenum, muscle) and did not affect ADG and serum IGF-I concentration. Collectively, the results suggest that dietary CS supplementation modulates the growth rate, serum IGF-I concentrations, and the gene expression of GHR, IGF-I, IGF-IR, IGFBP-3, and IR in a dose-dependent manner. CS supplementation has tissue-specific regulation of GHR, IGF-I, IGF-IR, and IGFBP-3 mRNA levels. Moreover, the results also imply the possible physiologic role of the GH-IGF axis in mediating the dietary CS supplementation-supported growth of finishing pigs.     

GnRH－A诱导泰和鸡母鸡排卵的生殖内分泌机制

本试验研究了促性腺激素释放激素类似物───［Ｄ－Ｌｅｕ￣６，Ｐｒｏ￣９］－ＧｎＲＨＮ－乙酰胺（ＧｎＲＨ－Ａ）诱导泰和鸡母鸡排卵的生理效应，藉此探讨其生殖内分泌机制。结果表明：（１）ＧｎＲＨ－Ａ具有显著刺激母鸡生殖器官发育的效应，导致母鸡卵巢、输卵管以及肝重增加（Ｐ＜０．０１），但对鸡体重没有显著的影响（Ｐ＜０．０５）；产蛋停止前１周施用ＧｎＲＨ－Ａ可维持母鸡正常产蛋的生殖生理状态。（２）ＧｎＲＨ－Ａ给药后最初２０ｄ诱发出两个鸡血浆促黄体生成素（ＬＨ）释放峰，处理组（ＧｎＲＨ－Ａ组）血浆ＬＨ浓度在此期间显著高于对照组（Ｐ＜０．０１）；然而与对照组相比较，处理组鸡血浆促卵泡素（ＦＳＨ）却没有明显变化（Ｐ＜０．０５）。（３）鸡血浆孕酮（Ｐ４）浓庆在施用ＧｎＲＨ－Ａ后明显上升，显著高于尚处休产期的对照组（Ｐ＜０．０１）。与此相反，给药后的囊初８ｄ内，鸡血浆雌二醇（Ｅ２）浓度明显降低，虽然随后略有回升，但仍低于对照组（Ｐ＜０．０１）。据此可以认为，ＧｎＲＨ－Ａ诱导卵巢和输卵管发育与鸡血浆ＬＨ、Ｐ４以及Ｅ２浓度变化密切相关，ＧｎＲＨ－Ａ是一种有效的制剂，可应用于诱导卵巢和输卵管发育及换羽前产蛋力的改善     

Antioxidant properties of several medicinal mushrooms

Three species of medicinal mushrooms are commercially available in Taiwan, namely, Ganoderma lucidum (Ling-chih), Ganoderma tsugae (Sung-shan-ling-chih), and Coriolus versicolor (Yun-chih). Methanolic extracts were prepared from these medicinal mushrooms and their antioxidant properties studied. At 0.6 mg/mL, G. lucidum, G. lucidum antler, and G. tsugae showed an excellent antioxidant activity (2.30-6.41% of lipid peroxidation), whereas C. versicolor showed only 58.56%. At 4 mg/mL, reducing powers were in the order G. tsugae (2.38) approximately G. lucidum antler (2.28) > G. lucidum (1.62) > C. versicolor (0.79). At 0.64 mg/mL, scavenging effects on the 1,1-diphenyl-2-picrylhydrazyl radical were 67.6-74.4% for Ganoderma and 24.6% for C. versicolor. The scavenging effect of methanolic extracts from G. lucidum and G. lucidum antler on hydroxyl radical was the highest (51.2 and 52.6%) at 16 mg/mL, respectively. At 2.4 mg/mL, chelating effects on ferrous ion were in the order G. lucidum antler (67.7%) > G. lucidum (55.5%) > G. tsugae (44.8%) > C. versicolor (13.2%). Total phenols were the major naturally occurring antioxidant components found in methanolic extracts from medicinal mushrooms. Overall, G. lucidum and G. tsugae were higher in antioxidant activity, reducing power, scavenging and chelating abilities, and total phenol content.     

Anti-inflammatory and antifibrotic effects of naringenin in diabetic mice

Renal protective effects of naringenin at 0.5, 1, and 2% of the diet in diabetic mice were examined. Naringenin supplemented at 1 and 2% increased its deposit in liver and kidney of diabetic mice. Compared with the diabetic control group, naringenin treatments at 1 and 2% lowered plasma levels of glucose and blood urea nitrogen, as well as increased insulin level and creatinine clearance (P < 0.05). Naringenin treatments dose-dependently reduced renal tumor necrosis factor-α level and expression (P < 0.05) but only at 1 and 2% significantly decreased production and expression of interleukin (IL)-1β, IL-6, and monocyte chemoattractant protein-1 (P < 0.05). Naringenin intake at 2% decreased renal formation and expression of type IV collagen, fibronectin, and transforming growth factor-β1 (P < 0.05). This compound at 1 and 2% lowered protein kinase C activity and suppressed nuclear factor κB (NF-κB) p65 activity, mRNA expression, and protein production in kidney. However, this agent only at 2% diminished NF-κB p50 activity, mRNA expression, and protein production (P < 0.05). These results indicate that naringenin could attenuate diabetic nephropathy via its anti-inflammatory and antifibrotic activities.     

电融合化学激活前培养时间对绵羊重构胚发育的影响

采用绵羊（Bos gaurus）体细胞带下注入体外成熟的卵母细胞构建重构胚,比较了不同的融合和化学激活前培养时间对重构胚融合和发育的影响。融合前培养 1h,比较不同的激活前培养时间,发现各组重构胚卵裂率、桑椹胚率和囊胚率均无显著差异（P>0.05）,但激活前培养2h胚胎完整率(95.81%)高于对照（74.64%）,差异显著（P<0.05）;激活前培养2 h,比较不同的融合前培养时间,发现两组融合率,激活胚胎完整率和囊胚率无显著差异（P>0.05）,但融合前培养1h的卵裂率（76.88%）和桑椹胚率（40.63%）显著高于直接融合（64.48%和21.50%）（P<0.05）。利用G1和G2培养早期克隆胚胎,将发育至桑椹胚囊胚的胚胎移植到41只受体绵羊,仅1只妊娠但于第104天流产。用5对绵羊微卫星DNA多态性引物对该克隆流产胎儿皮肤成纤维细胞、供体细胞、受体绵羊及一只普通对照母绵羊皮肤成纤维细胞进行微卫星DNA分析,结果表明5对微卫星DNA引物扩增各组细胞DNA, 扩增产物经过10%琼脂糖凝胶电泳和银染后,条带均有明显的多态性。条带分析显示,克隆流产胎儿的微卫星DNA指纹与供体细胞完全相同,而不同于其受体母亲和对照绵羊。证明该流产羔羊基因来源于供体细胞,为体细胞克隆绵羊。     

邻苯二甲酸二乙基己酯（DEHP）胁迫下红鳍笛鲷不同组织生化指标的变化

以红鳍笛鲷（Lutjanus erythropterus）幼鱼为实验生物,根据急性毒性实验结果（96hLC50为10.73mg·L-1）设置邻苯二甲酸二乙基己酯（DEHP）的浓度为0.12、0.60、3.00mg·L-（1以丙酮为对照）,在实验进行6、12、24、48h和96h时,分别检测肝脏和鳃组织超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量,以及脑组织乙酰胆碱脂酶（AChE）活性。结果表明,肝脏组织中的SOD反应灵敏且活性明显被诱导,低剂量组（0.12、0.60mg·L-1）SOD活性受到的诱导效应较高剂量组（3.00mg·L-1）更明显;与对照组比较,肝组织中MDA含量在DEHP曝露的12h显著性升高,但48h的MDA含量显著性降低（P〈0.01）,随曝露时间呈波动变化。鳃组织中的SOD活性明显低于肝脏组织,整个过程中表现为先升高后降低的变化规律,其中高剂量组（3.00mg·L-1）受到的诱导最明显;与对照组比较,MDA含量12h后即显著升高（P〈0.01）,随后MDA含量开始下降并围绕对照组水平上下波动。各剂量组脑组织AChE活性仅在6h受到抑制,此后受到明显的诱导作用酶活性升高,24h达到最大值,并显著高于对照组（P〈0.01）,但96h后恢复到对照组水平,呈明显的时间-效应关系。以上结果显示,DEHP对红鳍笛鲷幼鱼组织酶活在实验浓度下影响显著,对水生生物存在危害,应对其生态风险加以关注。     

三种方法对细胞周期诱导效率的比较

比较两种处理方法对细胞周期调控的影响,本研究用饥饿法,胸腺嘧啶处理法和饥饿法结合胸腺嘧啶法诱导胎儿成纤维细胞进入G1/G0期。诱导两周后,收集3种方法来源的细胞用流式细胞技术、细胞活力检测、real-time PCR和核型分析检查细胞诱导效率、细胞活力、成纤维细胞特异基因的表达水平和核型情况。结果表明,实验组细胞G1/G0期比率显著高于对照组（p〈0.05）;实验组中,饥饿联合药物诱导法比饥饿法和药物法稍高,但未达显著水准。实验组与对照组细胞核型正常,均为40条染色体,性染色体为XX。细胞活力和显示,对照组比试验组稍高,但差异不显著（p〉0.05）;FGF4、FGF2及Sox2的基因表达水平在各组间差异不显著（p〉0.05）。这些结果表明,实验组3种方法对细胞特性没有显著影响,饥饿结合药物诱导可适当提高细胞诱导效率,为相关研究提供参考。     

Dose rate effect of gamma irradiation on phenolic compounds, polyphenol oxidase, and browning of mushrooms (Agaricus bisporus).

To enhance the shelf life of edible mature mushrooms, Agaricus bisporus, 2 kGy ionizing treatments were applied at two different dose rates: 4.5 kGy/h (I(-)) and 32 kGy/h (I(+)). Both I(+) and I(-) showed a 2 and 4 day shelf-life enhancement compared to the control (C). Before day 9, no significant difference (p>0.05) in L value was detected in irradiated mushrooms. However, after day 9, the highest observed L value (whiteness) was obtained for the mushrooms irradiated in I(-). Analyses of phenolic compounds revealed that mushrooms in I(-) contained more phenols than I(+) and C, the latter containing the lower level of phenols. The fluctuation of the precursors of glutaminyl-4-hydroxyaniline (GHB) was less in I(-) than in I(+). The polyphenol oxidase (PPO) activities of irradiated mushrooms, analyzed via catechol oxidase, dopa oxidase, and tyrosine hydroxylase substrates, were found to be significantly lowered (p = 0.05) compared to C, with a further decrease in I(+). Analyses of the enzymes indicated that PPO activity was lower in I(+), contrasting with its lower phenols concentration. The observation of mushrooms' cellular membranes, by electronic microscopy, revealed a better preserved integrity in I(-) than in I(+). It is thus assumed that the browning effect observed in I(+) was caused by both the decompartmentation of vacuolar phenol and the entry of molecular oxygen into the cell cytoplasm. The synergetic effect of the residual active PPO and the molecular oxygen, in contact with the phenols, allowed an increased oxidation rate and, therefore, a more pronounced browning I(+) than in I(-).     

NP-1在小球藻硝酸还原酶缺失突变体中的表达与活性检测

摘 要：小球藻繁殖快,培养简单,用转基因小球藻表达目的基因产物具有重要的应用前景。本研究构建了兔防御素NP-1的植物表达载体,NP-1由Ubiquitin启动子控制,含NPTII基因和硝酸还原酶基因两个筛选标记。以椭圆小球藻(Chlorella ellipsoidea)硝酸还原酶缺失突变体nrm-4为受体,采用原生质体转化的方法将目的基因转入该突变体中。用含G418的硝酸盐培养基筛选出阳性藻落,经PCR和RT-PCR检测,证明获得了转基因藻株。转基因藻株在无抗生素筛选压力的硝酸盐培养基上继代培养后进行抑菌活性检测。研究表明,转基因椭圆小球藻表达的NP-1具有正常的生物活性,并在无抗生素的培养基中稳定遗传。本研究的结果为小球藻表达外源基因提供了新的技术途径,也为NP-1的规模化生产奠定了基础。     

Nutritional effects of enzymatically modified soybean oil with caprylic acid versus physical mixture analogue in obese Zucker rats

Enzymatically modified soybean oil with caprylic acid (SL), a physical mixture of tricaprylin and soybean oil (PHY), and soybean oil as control were fed (20% of diet weight) to female obese Zucker rats. Both lipids (SL and PHY) have similar total fatty acid composition containing 23.4 mol % caprylic acid (C8:0) but have different lipid structures. After 21 days of feeding, the body weight gain was 36.4% in the SL-fed group and 35.2% in the PHY-fed group, respectively; whereas the body weight of the control group increased 41.6%. Significant differences in the respiratory exchange ratio were observed between the SL and PHY groups. However, the contents of glucose, total and high density lipoprotein (HDL) cholesterol, and very low density and low density lipoprotein (VLDL + LDL) cholesterol in serum were not significantly different between the SL- and PHY-fed groups or among the three dietary groups (control, SL, and PHY) (p < 0.05). On the other hand, plasma total cholesterol and plasma triacylglycerol (TAG) were significantly higher in SL- and PHY-fed groups than in the control group. In the liver and inguinal adipocyte TAG, C8:0 was found in the SL-fed group, whereas it was not observed in the liver and inguinal adipocyte TAG of the PHY-fed group, which suggests that positional distribution of C8:0 of the TAG molecule is an important consideration in the metabolism of lipids. This study showed that different positional distribution in TAG molecules lead to different metabolic fates, resulting in the change of fatty acid composition in liver and inguinal adipose TAG in female Zucker rats.