4种饲料投喂对鲻(Mugil cephalus)生长及鱼体组成的影响

以初始体重(25.0±1.59) g的鲻为研究对象,通过8周的生长实验,研究不同饲料投喂对鲻的生长及鱼体生化组成的影响。处理组分别为面粉组(T1)、米糠组(T2)、虾料组(T3)和鱼料组(T4)。研究结果显示,在室内水族缸内单一地使用面粉或米糠投喂,鲻几乎不生长,但仍能维持较高的成活率(>80%)。虾料组的特定生长率(1.46 %/d)和饲料效率(48.62%)均为各组最高,约为鱼料组的两倍,且两组的特定生长率和饲料效率均显著高于面粉组和米糠组(P<0.05)。面粉组和米糠组的周均日摄食量在第4周后迅速降低(<0.80 g/d),而整个养殖期间虾料组和鱼料组普遍高于0.80 g/d,且在第8周明显升高。养殖结束时全鱼的粗蛋白以米糠组最高(18.62%±1.36%),粗脂肪以虾料组最高(10.52%±0.36%)。面粉组有较明显的粗脂肪积累(8.01%±0.42%)。研究结果表明,碳水化合物(面粉)水平的提高会促进鲻全鱼脂肪的积累,用米糠代替配合饲料投喂时可维持鲻的粗蛋白含量水平。     

Non-Destructive Quantification of Lipid and Water in Fresh Tuna Meat by a Single-Sided Nuclear Magnetic Resonance Scanner

A portable single-sided nuclear magnetic resonance (NMR) surface scanner was applied to the non-destructive quantification of lipid and water in meat block samples of farmed bluefin tuna (Thunnus thynnus). Proton NMR relaxation measurements of the fresh meat block samples were performed at room temperature in a laboratory. Totally, 34 tuna meat block samples were measured; the required measurement time was approximately 70 s for each sample. The results yielded estimation errors of 3.7 and 2.7 g/100 g for the lipid and water weight fractions, respectively. The investigation depth of the sensor was as deep as 3 cm, which enables the non-destructive quantification of the meat of the intact whole tuna beneath the thick scales, skin, and subcutaneous fat in markets and seafood factories.     

低温胁迫对不同品种果蔗膜脂过氧化及渗透调节物质的影响

以4个引种果蔗品种幼苗叶片为试验材料,采用人工模拟低温环境对其进行低温胁迫,测定各品种叶片的相对电导率,丙二醛（MDA）、可溶性糖、可溶性蛋白和脯氨酸含量。结果表明,随处理时间的延长,4个引种果蔗品种幼苗叶片的相对电导率一直保持升高的趋势;MDA含量呈先显著升高后降低的趋势,分别在第7天和第10天达到最大值,顺序均为川蔗26号>拔地拉>闽引黄皮果蔗>桂果蔗1号。低温胁迫下,可溶性糖、可溶性蛋白质、脯氨酸含量呈上升趋势。随着低温处理时间的延长,叶片中可溶性糖和可溶性蛋白质含量明显增加。低温处理初期,脯氨酸含量急剧上升,随着处理时间延长脯氨酸含量开始缓慢降低,但整个过程中脯氨酸含量始终保持在较高水平。各项指标测定结果显示,4个引种果蔗品种的耐寒性表现为桂果蔗1号>闽引黄皮果蔗>拔地拉>川蔗26号。     

Amelioration of Hexachlorocyclohexane-Induced Oxidative Stress by Amaranth Leaves in Rats

The effect of prefeeding dehydrated amaranth leaves (AL), at 10 and 20% levels on hexachlorocyclohexane (HCH)-induced free radical stress in rat liver was evaluated. The HCH-induced raise in malonadialdehyde (MDA), conjugated dienes and hydroperoxides was diminished by AL. The effect of AL was highly effective with respect to reduction in these cytotoxic products, especially at 20% level. AL intake resulted in a significant increase in hepatic vitamin A and glutathione (GSH). However, the AL consumption reduced hepatic tocopherols. Feeding of AL at 10%level increased the hepatic glucose-6-phosphate dehydrogenase (G-6-PDH) activity while that at 20% level increased the hepatic glutathione reductase (GSSGR) as well, in addition to G-6-PDH. Amaranth leaves at 10 and 20% levels of feeding reduced the hepatic superoxide dismutase and glutathione peroxidase (GSH-Px) activities. The pre-feeding of AL resulted in the reversal of HCH-induced alteration in GSH-Px and G-6-PDH activities. The significant reduction in the level of glutathione S-transferase brought about by HCH was restored to control level by feeding 20% AL. It is concluded that the consumption of AL at 20% level produces reduction in the HCH-induced impairment of antioxidant status in rat liver.     

Effect of α tocopherol and selenium on antioxidant status, lipid peroxidation and hepatopathy induced by malathion in chicks

The objective of the present study was to investigate the role of α tocopherol and selenium on malathion induced hepatic damage, and antioxidant defense in chicks. The chicks were divided into three groups. First group received malathion 10 mg/kg BW, orally for 60 days, the second group received the same dose of malathion but was supplemented with α tocopherol and selenium for 60 days and the third group served as the control. A compromised antioxidant capacity as evidenced by increased levels of erythrocytic lipid peroxidation and decreased concentration of vitamin E and decreased activity of glutathione peroxidase was observed in chicks following the administration of malathion. An improved antioxidant status was observed in chicks of second group with α tocopherol and selenium supplementation including higher concentration of vitamin E, increased activity of glutathione peroxidase and lower levels of lipid peroxidation. Histopathological studies of liver in the chicks which received malathion exhibited, moderate to severe degenerative and necrotic changes in the hepatocytes. The correlation of decreased antioxidant status of chicks with degenerative changes in liver suggests that lipid peroxidation may be one of the important mechanism in the chronic toxicity of malathion. The results indicate that α tocopherol and selenium were effective in partially alleviating degenerative changes induced by malathion in the liver of chicks by attenuating processes leading to lipid peroxidation.     

外源一氧化氮供体SNP对水稻叶片中由硒引起的脂质过氧化的调节作用

一氧化氮(nitric oxide, NO)是植物中一种重要的信号分子, 在诱导种子萌发, 影响植物生长发育, 促进植物细胞衰亡等方面发挥着重要作用。然而对于外源NO是否参与了Se诱导的脂质过氧化调节过程仍不为人知。我们研究了0.2 μmol L^-1和20 μmol L^-1Na₂SeO₃及一氧化氮供体硝普钠(sodium nitroprusside, SNP)处理对水稻叶片叶绿素、H₂O₂和硫代巴比妥酸反应产物(Thiobarbituric Acid Reactive Substances, TBARS)含量, 愈创木酚过氧化物酶(guaiacol peroxidase, GPX)、超氧化物歧化酶(superoxide dismutase, SOD)、过氧化氢酶(catalase, CAT)以及抗坏血酸过氧化物酶(ascorbate peroxidase, APX)活性等生理生化指标的影响。结果表明, 1 μmol L^-1SNP处理促进GPX、APX和CAT活性, 缓解膜脂过氧化, 降低TBARS含量;显著提高0.2 μmol L^-1Na₂SeO₃处理下水稻叶片中叶绿素含量。在20 μmol L^-1Na₂SeO₃处理下, 外加1 μmol L^-1SNP更加显著促进GPX和CAT活性, 与此同时明显降低20 μmol L^-1Na₂SeO₃处理引起的H₂O₂含量上升, 并降低TBARS含量。NO对植物中由Se引起的脂质过氧化具有调节作用。     

Protective effect of vitamin C against chlorpyrifos oxidative stress in male mice

Pesticides may induce oxidative stress leading to generate free radicals and alternate antioxidant or oxygen free radical scavenging enzyme system. This study was conducted to investigate the acute toxicity of chlorpyrifos toward male mice and the oxidative stress of the sub-lethal dose (1/10 LD₅₀) on the lipid peroxidation level (LPO), reduced glutathione content (GSH) and antioxidant enzymes; catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glucose-6-phosphate dehydrogenase (G6PD), and glutathione-S-transferase (GST) activities. Also, the protective effects of vitamin C (200 mg/kg body weight, bw) 30 min before or after administration of chlorpyrifos were investigated. The results demonstrated that the LD₅₀ value of chlorpyrifos was 134.95 mg/kg bw. The oral administration of 13.495 mg/kg chlorpyrifos significantly caused elevation in LPO level and the activities of antioxidant enzymes including CAT, SOD and GST. However, GPx activity remained unchanged, while the level of GSH and G6PD activity were decreased. Vitamin C treatment to chlorpyrifos intoxicated mice decreased LPO level and GST activity, normalized CAT, SOD and G6PD activities, while GSH content was increased. We conclude that vitamin C significantly reduces chlorpyrifos-induced oxidative stress in mice liver and the protective effect of the pre-treatment with vitamin C is better than the post-treatment.     

The effects of Saw palmetto on flumethrin-induced lipid peroxidation in rats

In the present study, 40 male Wistar albino rats were used and divided into 4 groups. The first group served as the control group; the second group was administered Saw palmetto extract at the dose of 20 mg/kg/bw; the third group was administered flumethrin at the dose of 15 mg/kg/bw; and the fourth group was administered a combination of 20 mg/kg/bw Saw palmetto extract and 15 mg/kg/bw flumethrin, for 21 days, orally. After the trial period, blood and tissue (liver, kidney and brain) samples were taken from the rats. Saw palmetto extract did not cause significant alterations in plasma and tissue malondialdehyde (MDA) levels, serum and tissue nitric oxide (NO) levels, erythrocyte and tissue superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities when compared to the controls (p > 0.05). Flumethrin led to increased plasma and tissue MDA levels, serum and tissue NO levels, tissue GSH-Px activities and decreased erythrocyte and tissue SOD and CAT activities, and erythrocyte GSH-Px activity, compared to the controls (p < 0.05). The flumethrin and Saw palmetto extract combination increased erythrocyte SOD activity and decreased brain GSH-Px activity as compared to flumethrin (p < 0.05). In conclusion, it was determined that Saw palmetto extract did not cause any negative effect on the prooxidant-antioxidant balance. While flumethrin stimulated lipid peroxidation; Saw palmetto extract at the dose of 20 mg/kg/bw did not exhibit enough antioxidant effect in rats.     

Modulation of ethion-induced hepatotoxicity and oxidative stress by vitamin E supplementation in male Wistar rats

Organophosphorus insecticides (OPIs) may induce oxidative stress leading to generation of free radicals and alteration in antioxidant system of animals. Many studies reported that enzymatic and non-enzymatic antioxidant may play protective role against OPIs induced toxicity in human and rats. The aim of present study was to investigate the possible protective role of vitamin E on ethion-induced hepatotoxicity in rats using qualitative, quantitative and biochemical approaches. Adult male albino rats of Wistar strain were randomly divided into four groups; each group consists of six animals. Animals were treated for a period of 28 days. Group I (control group received corn oil); Group II [ethion treated (2.7 mg/kg bw/day)]; Group III (vitamin E treated (50 mg/kg of bw/day)]; Group IV (ethion + vitamin E treated). Animals were sacrificed after 7, 14, 21 and 28 days by decapitation and liver tissue was used for the measurement of proteins, lipid peroxidation (LPO), reduced glutathione (GSH) content and activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) glutathione reductase (GR) and glutathione-S-transferase (GST). Erythrocytes were analyzed for acetyl cholinesterase activity. The result of this study shows that in vivo administration of ethion caused a significant induction of oxidative damage in liver tissue as evidenced by increased level of LPO and decreased GSH content. Ethion toxicity also led to a significant increase in the activities of SOD, CAT, GPx and GST in liver tissue. In addition, decrease in GR activity was observed in ethion administered rats compared to control. Histopathological findings revealed that exposure to ethion caused damage in liver tissue. However, simultaneous supplementation with vitamin E restored these parameters partially. In conclusion, the results of the current study revealed that ethion-induced toxicity caused lipid peroxidation, alterations in the antioxidant enzymes and histopathological changes in liver. Supplementation of vitamin E exhibited protective effect by inhibiting ethion-induced toxicity in liver and erythrocytes.     

两种抗病基因双T-DNA区双元载体的构建

选择标记基因的删除是植物转基因工程中重要的步骤之一,双T-DNA区双元载体转化法以其共整合频率高、删除标记基因效率高的优点在植物遗传转化中应用非常广泛。本文通过构建天麻抗真菌蛋白基因、脂质转移蛋白基因双T-DNA区双元载体,为培育不含选择标记基因的抗病新材料奠定基础。通过PCR的方法克隆GAFP基因,产物纯化测序确定序列准确后与pSB130-35S载体进行BamHⅠ、SacⅠ双酶切;pCAMBIA2300-LTP、pSB130-35S经EcoRⅠ、HindⅢ双酶切,酶切产物纯化后连接,连接产物转化大肠杆菌。采用基因特异性引物进行菌液PCR鉴定阳性克隆,重组质粒pSB130-GAFP、pSB130-LTP双酶切产物大小分别为540bp、1200bp,与预期产物大小一致,pSB130-GAFP、pSB130-LTP双T-DNA区双元载体构建成功。载体pSB130-GAFP、pSB130-LTP转化根癌农杆菌后可以直接用于植物的遗传转化。