兰州百合连作土壤水浸液自毒作用研究

【目的】探讨兰州百合(Lilium davidii var.unicolor salisb)连作土壤水浸液对自身幼苗生长的障碍因素及其作用机制。【方法】设置蒸馏水(CK)及正茬、连作2年、连作4年兰州百合根际土壤水浸液各50,100,200,300 mg/mL,共13个处理,以兰州百合种球为受试对象,测定不同条件下兰州百合幼苗生长、抗氧化酶活性、渗透调节物质及细胞膜透性的变化,并利用GC-MS技术分析各处理土壤中存在的主要自毒物质。【结果】正茬、连作2年及连作4年兰州百合根际土壤水浸液对兰州百合幼苗的生长均存在"低促高抑"现象,且抑制作用随连作年限的延长而增强。随水浸液质量浓度的增加,兰州百合幼苗CAT和SOD活性逐渐升高,POD活性先上升后下降,MDA含量、相对电导率、脯氨酸及可溶性糖含量的变化呈不断上升趋势,当水浸液质量浓度上升至300 mg/mL时,3个处理中各指标的上升或下降程度与对照相比均达显著差异水平(P0.05)。兰州百合正茬、连作2年及连作4年根际土壤中分别鉴定出9,15和17种化合物,主要包括2,3-丁二醇、1,2,3-三甲苯、邻苯二甲酸二丁酯、对苯二甲酸二辛酯、抗氧剂2246等化合物,其中大部分为自毒物质。【结论】兰州百合正茬、连作2年及连作4年根际土壤水浸液质量浓度达到300 mg/mL时,对其幼苗的生长会产生显著抑制作用。连作土壤中存在的自毒物质可以改变兰州百合植株体内的抗氧化酶活性,破坏细胞膜结构和功能,抑制兰州百合植株的生长,是导致兰州百合连作障碍发生的重要原因之一。     

灰霉菌侵染对番茄幼苗活性氧积累及抗氧化酶活性的影响

为进一步分析活性氧和抗氧化防御系统在番茄抗病信号调控机制中的作用,为提高产量和品质提供科学依据,以4叶1心的番茄幼苗为试验材料,比较番茄幼苗受灰霉菌侵染后叶片O_2~-·以及抗氧化酶、内源褪黑素等的变化。结果表明:番茄幼苗接种灰霉菌后,随着时间的延长,幼苗叶片上病斑斑点逐渐增多,灰霉菌含量显著增多,叶色逐渐变浅,植株表现明显的发病症状;灰霉病菌侵染后番茄体内O_2~-·活性爆发,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性下降,过氧化氢酶(CAT)和谷胱甘肽还原酶(GR)活性上升,褪黑素含量增加;上述变化都是番茄幼苗为了抵御灰霉菌的生物胁迫而发生的应激反应。综上,植物在遭受病原菌等生物胁迫时不能简单地推断SOD、CAT和POD等抗氧化酶活性一定升高,植物抵御病原菌侵染更多地依赖于抗性信号路径中信号物质的激活和积累。     

Effects of dietary supplementation of Haematococcus pluvialis powder on gonadal development,coloration and antioxidant capacity of adult male Chinese mitten crab (Eriocheir sinensis)

The green algae Haematococcus pluvialis is an important source of natural astaxanthin as feed additive. This study was conducted to investigate the effects of dietary supplementation of H. pluvialis powder on gonadal development, coloration and antioxidant capacity of adult male Chinese mitten crab Eriocheir sinensis, and four experimental diets were formulated to contain 0, 0.2%, 0.4% and 0.6% of H. pluvialis powder. There were four treatments (defined as D1~D4) in this study and each treatment had three replicates. Dietary H. pluvialis contents had no significant effects on survival, body weight gain rate and gonadal development of male E. sinensis. For colour parameters, the total carotenoids content in carapace and hepatopancreas as well as hepatopancreatic lightness (L*) and carapace redness (a*) increased significantly with increasing dietary H. pluvialis (p < 0.05). For the antioxidant indices in the serum, D4 had the lowest activities of superoxide dismutase (SOD) and peroxidase (POD), but the highest glutathione peroxidase (GSH‐Px) and lactic dehydrogenase (LDH), while the malondialdehyde (MDA) in serum and hepatopancreas decreased significantly with the rising content of dietary H. pluvialis (p < 0.05); D1 had the highest levels of SOD, POD and GSH‐Px in hepatopancreas. For the non‐specific immune indices, the highest activities of acid phosphatase (ACP) and γ‐glutamyl transpeptidase (γ‐GT) were found on the serum of D3 and D4 (p < 0.05). D1 had the highest levels of ACP and alkaline phosphatase (ALP) in hepatopancreas, while D2 and D3 had the lowest levels of ALP and ACP respectively. These results suggested the optimal dietary natural astaxanthin level was around 40 mg/kg diets.     

Comparison of immune responses and antioxidant status of different generations of growth‐selected Portunus trituberculatus families

The purpose of this study was to investigate the effects of inbreeding on the immune responses and antioxidant status of Portunus trituberculatus juveniles. Results showed that inbreeding affected the total haemocyte count, and phagocytic, pro‐phenoloxidase (propo), phenoloxidase and antibacterial activities decreased after the seventh generation. Antioxidant status showed a similar pattern: total antioxidant capacity, superoxide dismutase (SOD) activity and GSH/GSSG in the cell‐free haemolymph and hepatopancreas decreased, while catalase activity in the cell‐free haemolymph increased (P < 0.05). There were no significant differences in α₂‐macroglobulin and bacteriolytic activities in the cell‐free haemolymph and glutathione peroxidase activity in the cell‐free haemolymph and hepatopancreas among nine inbreeding generations. Gene expression levels of proPO and crustin in haemocytes and SOD in haemocytes and hepatopancreas also decreased significantly as the inbreeding generations increased. The results suggest that a high level of inbreeding could severely reduce the physiological health of P. trituberculatus. Our obtained data would be particularly useful for P. trituberculatus breeding programmes.     

饲料脂肪水平对俄罗斯鲟幼鱼生长、血液生化指标及抗氧化性能的影响

以鱼油、豆油、亚麻籽油等比例混合,配成脂肪含量分别为5.45%(L1)、7.00%(L2)、10.44%(L3)、14.37%(L4)、16.34%(L5)、18.91%(L6)及20.15%(L7)的等氮饲料,饲喂俄罗斯鲟(Acipenser gueldenstaedtii)幼鱼[(6.20±0.02)g]8周。实验结果表明,L3组的终末体质量、增重率最大,但与L2组间无显著差异(P0.05),L3组的蛋白质效率显著高于其它组(P0.05),且饲料系数最低。L6和L7组终末体质量、增重率和蛋白质效率显著低于L2和L3组(P0.05)。将幼鱼的增重率与饲料脂肪水平进行回归分析,得出俄罗斯鲟幼鱼在饲料脂肪水平为10.69%时生长最佳。随着饲料脂肪水平的升高,各组鱼的肝体比和体粗脂肪有上升趋势,其中肝体比在饲料脂肪含量大于14.37%时显著增大(P0.05)。血清中的甘油三酯、胆固醇含量也随脂肪水平升高而显著提高(P0.05),提示脂肪过高会影响俄罗斯鲟幼鱼的生长,降低蛋白质效率,导致脂肪在体内的过量积蓄。L7组鱼血清中高密度脂蛋白胆固醇含量最高,而L1组鱼的低密度脂蛋白胆固醇含量最高。肝脏脂蛋白酯酶活性随饲料脂肪水平的提高而升高,脂肪酸合成酶活性则随脂肪水平升高而降低,提示饲料脂肪水平的提高会促进鱼体脂肪的分解代谢。肝脏丙二醛含量和超氧化物歧化酶活性均随着饲料脂肪水平的提高显著升高(P0.05),表明脂肪含量过高会导致脂质过氧化,引发机体抗氧化酶活性的升高。综合俄罗斯鲟幼鱼的生长、血液指标及抗氧化性能,建议生产中将幼鱼的饲料脂肪水平控制在7.00%~10.69%。     

Characterization of Spray-Dried Hydrolyzed Proteins from Pink Perch Meat Added with Maltodextrin and Gum Arabic

In the present study, spray-dried pink perch meat protein hydrolysate (PPH) and hydrolysate with maltodextrin and gum arabic (PPHMG) were characterized in relation to their physical, rheological, functional, antioxidant, thermal, and sensory properties. The Herschel–Bulkley model was suitable to explain the flow behavior of PPH and PPHMG emulsions. Both the samples exhibited functional and antioxidant properties. Antioxidant activities were significantly higher for PPH compared with PPHMG (p<0.05). PPH and PPHMG alone did not exhibit antimicrobial activity but enhanced the activity of chitosan against pathogens. Sensory acceptability of the samples in soup revealed that PPHMG of up to 4% was highly scored without any traces of bitterness, whereas for PPH, a concentration of up to 3% was acceptable.     

Oxidative Stability of Common Kilka (Clupeonella cultriventris caspia) Oil Supplemented with Microwave Extracted Ghure (Unripe Grape) Marc Extract

The objective of this study was to evaluate the effect of microwave extracted Ghure (unripe grape) marc extract on common kilka (Clupeonella cultriventris caspia) oil oxidation during accelerated storage. The antioxidant activity of Ghure marc extract was compared with those of α-tocopherol and BHT. The Ghure marc extract significantly reduced the peroxide and p-anisidine value of kilka oil. Even though the effect of Ghure marc extract on reducing the oxidation of kilka oil was similar to the effect of BHT, it was functionally more effective than α-tocopherol. Generally, Ghure marc extract could be considered as a potential source of natural antioxidants, with inexpensive costs, for improving the oxidative stability of kilka oil.

Abbreviations: AA, Antioxidant activity; AOP, Antioxidant power; AV, p-Anisidine value; CUPRAC, Cupric ion reducing antioxidant capacity; DHA, Docosahexaenoic acid; EPA, Eicosapentaenoic acid; FIC, Ferrous ion chelating; GME, Ghure marc extract; FRAP, Ferrous ion reducing antioxidant power; KO, Kilka oil; IP, Induction period; MAE, Microwave-assisted extraction; MUFA, Monounsaturated fatty acid; PUFA, Polyunsaturated fatty acid; PV, peroxide value; PF, Protection factor; RSA, Radical scavenging activity; SFA, Saturated fatty acids; TFC, Total flavonoid content; TPC, total phenolic content TV, totox value.     

Antioxidant activity and lipid peroxidation in Artemia nauplii enriched with DHA‐rich oil emulsion and the effect of adding an external antioxidant based on hydroxytyrosol

Artemia nauplii catabolize polyunsaturated fatty acids (PUFA); in particular, they retroconvert docosahexaenoic acid (DHA, 22:6n‐3), so enrichment is a continuous quest towards increasing PUFA through the use of PUFA‐rich enrichment products. However, optimal conditions during enrichment (aeration, illumination and temperatures around 28°C) tend to accelerate autoxidation of PUFA and the formation of potentially toxic oxidation products. Water‐soluble antioxidants like the polyphenolic compound hydroxytyrosol (3,4‐dihydroxyphenylethanol), a polar molecule found in the water fraction resulting after the milling process of olives, arise as promising compounds to prevent oxidation during Artemia enrichments. We investigated the antioxidant activity and lipid peroxidation in Artemia nauplii during enrichment and the effect of adding an external antioxidant based on hydroxytyrosol during the enrichment with a PUFA‐rich emulsion (M70). For this purpose, the activity of antioxidant enzymes (catalase, superoxide dismutase, glutathione‐S‐transferase, glutathione peroxidase), as well as lipid peroxidation, was determined in enriched and unenriched Artemia nauplii. To validate antioxidant activity and lipid peroxidation, in a first experiment, nauplii were enriched with microalgae (Tetraselmis suecica), yeast (Saccharomyces cerevisiae) and M70 emulsion. In a second experiment, enrichment with a commercial emulsion (DC Super Selco), M70, and a combination of M70 and hydroxytyrosol (Hytolive, HYT) added as an external antioxidant were performed. The combination of M70 with HYT produced the best results, in terms of activity of antioxidant enzymes. The analysis of the fatty acids from total lipids showed that the addition of hydroxytyrosol preserved the DHA percentage of enriched nauplii.     

火龙果茎多糖的超高压提取及抗氧化活性研究

为研究火龙果茎多糖的超高压提取工艺及抗氧化活性。在单因素试验基础上,采用Box-Behnken设计和响应面分析方法,确定超高压提取的最优工艺,并从清除ABTS自由基和DPPH自由基能力方面来评价火龙果茎多糖的体外抗氧化能力。结果表明,火龙果茎多糖的超高压提取的最佳工艺条件为:液固比10∶1(m L∶g)、超高压压力300 MPa、超高压时间4 min。在此工艺条件下多糖得率为(2.83±0.02)%。火龙果茎对ABTS自由基和DPPH自由基具有清除作用,对ABTS自由基和DPPH自由基的清除率IC_(50)分别为浓度为4.3 mg/m L和5.5 mg/m L时。