浓缩苹果汁中甲胺磷残留量测定的最佳条件选择

用双氧水测定浓缩苹果汁中甲胺磷残留量的最佳处理条件是:双氧水添加量8%、pH值7、处理温度50℃以下、处理时间5 min.     

外源过氧化氢对枳生长、侧根数和根系碳水化合物含量的影响

研究不同浓度（0~1.25 μM）过氧化氢（H2O2）对枳实生苗生长、根系形态、侧根数、根系葡萄糖、果糖和蔗糖含量的影响。结果表明,与0 μM H2O2比较,只有外源0.25 μM H2O2显著提高了枳株高和叶片数,0.05 μM和0.25 μM H2O2显著提高了根系鲜重,0.05 μM、0.25 μM和1.25 μM H2O2均显著提高根系干重、形态和一级、二级、三级侧根数以及根系果糖、葡萄糖含量。其中,0.25 μM H2O2是促进效应最显著的。     

外源过氧化氢对干旱胁迫下温室黄瓜叶绿体超微结构和抗氧化酶的影响

 以温室黄瓜品种‘春光2号’为试材, 用100 g·L ^{- 1}聚乙二醇处理模拟干旱胁迫, 研究外源过氧化氢是否通过提高叶片抗氧化酶的活性来减轻干旱胁迫对叶绿体膜的伤害。结果表明: 干旱胁迫处理48 h后, 叶绿体肿胀变圆, 叶绿体膜和类囊体模糊不清。与干旱胁迫前没有经过预处理的幼苗相比, 经外源过氧化氢预处理后再干旱胁迫48 h的幼苗中大部分的叶绿体结构正常, 叶片的超氧化物歧化酶、过氧化氢酶、愈创木酚过氧化物酶、抗坏血酸过氧化物酶、单脱氢抗坏血酸还原酶、脱氢抗坏血酸还原酶和谷胱苷肽还原酶等抗氧化物酶的活性以及抗坏血酸和还原型谷胱苷肽的含量明显增高, 内源过氧化氢含量、超氧阴离子的产生速率和丙二醛的含量则显著降低。所以, 外源过氧化氢预处理能够提高抗氧化物的活性,降低活性氧的积累, 从而缓解干旱对黄瓜叶绿体膜的伤害。     

光合细菌产氢研究进展

氢气是目前最常用的清洁能源,具有能量含量高和清洁燃烧的特点。制氢的方式有多种,生物制氢与传统物理和化学工艺制氢相比,是最清洁的一种方法。然而,大规模生物制氢的产氢量与产氢率往往受到各种环境等因素的限制。近年来的许多研究突破了环境因素的限制,从微生物代谢、能源来源及微生物产氢关键酶等方面有效提高了微生物产氢效率。本文总结了生物制氢的几种主要方法,详细讨论了光合细菌产氢的影响因素,并对其有效促进途径的研究进展进行了综述,以期为生物制氢领域的深入研究提供参考,为工业大规模制氢、减轻环境污染做出贡献。     

Induction of disease resistance and ROS metabolism in navel oranges by chitosan

The objective of this work was to evaluate how disease resistance and reactive oxygen species (ROS) metabolism in harvested navel oranges (Citrus sinensis L. Osbeck) may be affected by chitosan. Fresh navel oranges were treated with 2% chitosan or 0.5% glacial acetic acid (control) solution for 1 min, and some were inoculated with Penicillium italicum and Penicillium digitatum. Then, the fruit were stored at 20 °C and 85–95% RH. Treatment with 2% chitosan significantly reduced the disease incidence and the lesion diameter compared with control fruit. This treatment effectively enhanced the activities of peroxidase (POD) and superoxide dismutase (SOD), and levels of glutathione (GSH) and hydrogen peroxide (H₂O₂), inhibited the activities of catalase (CAT) and the decreases of ascorbate (AsA) content during navel orange fruits storage. Ascorbate peroxidase (APX) activity in the navel orange fruit was induced slightly by the chitosan treatment during 14–21 days storage. However, glutathione reductase (GR) activity in the fruit was not enhanced by the chitosan treatment. These results indicated that chitosan treatment could induce the navel orange fruit disease resistance by regulating the H₂O₂ levels, antioxidant enzyme and ascorbate–glutathione cycle.     

提高氨化处理秸秆粗蛋白含量的适宜方法研究

为提高秸秆粗蛋白含量,以氢氧化钠、过氧化氢、生石灰、熟石灰、尿素为处理剂,进行不同浓度和不同组合方式处理小麦秸和莜麦秸的试验.结果表明:尿素与氢氧化钠的组合对提高秸秆粗蛋白含量极为有效,5%以上的生石灰与尿素组合提高效率最高,为单纯5%尿素氨化法的4倍.建议生产中根据需要确定尿素剂量.     

Endogenous hydrogen sulfide results in increase of reactive oxygen species induced by angiotensin II in neurons

AIM：To determine the effect of endogenous hydrogen sulfide (H2S) on the production of reactive oxygen species (ROS) in medullary neurons induced by angiotensin II (Ang II). METHODS：Primary cultured rat medullary neurons were used in the study. Identification of medullary neurons and the co-expression of cystathionine β-synthetase (CBS) were detected by double-labeling immunofluorescence. Medullary neurons were treated with Ang II in the presence or absence of sodium butyrate (NaBu, a CBS agonist; 100 μmol/L, 250 μmol/L and 500 μmol/L). ROS production was measured by dihydroethidium staining. The activity of total superoxide dismutase (SOD) was detected by ELISA. The mRNA expression of CBS was determined by real-time PCR. RESULTS：The medullary neurons in the cultured cells were over 90%. Ang II (1 μmol/L) significantly increased ROS level in the medullary neurons. Ang II inhibited the activity of total SOD in the medullary neurons. CBS was expressed in the medullary neurons. Ang II decreased the mRNA expression of CBS. NaBu (250 μmol/L and 500 μmol/L) inhibited ROS production induced by Ang II with a dose-dependent manner, while NaBu alone had no influence on the ROS level in the medullary neurons. CONCLUSION：Ang II increases the level of ROS in medullary neurons partly by inhibiting the activity of total SOD and the mRNA expression of CBS. Endogenous H2S inhibits the ROS level increased by Ang II in the medullary neurons.     

Effect of Environmental Temperature on Digestive Tract,Visceral Organ Size,Digestibility and Energy Metabolism in Rats Fed Different Levels of Pea Fibre

Abstract

A study was performed to investigate the effect of environmental temperature (18°C or 28°C) and increasing levels of pea fibre in the diet on digestive tract, visceral organ size, digestibility and energy metabolism in rats. Thirty-six male Wistar rats, initial liveweight (LW) 77-79 g, were allocated to six groups and housed at either 18°C (three groups) or 28°C (three groups). Three wheat starch, fish meal and pea fibre-based diets were prepared to contain 100, 200 and 300 g pea fibre kg^?1 (68, 110 and 157 g dietary fibre kg^?1 DM) and 160 g protein (N × 6.25) kg^?1. One group of rats at each temperature was fed one of the diets for four balance periods. Gas-exchange measurements were made and urine and faeces were quantitatively collected. Food to gain ratio was higher (P <.05) at 18°C than at 28°C and increased (P <.05) as the level of fibre was increased. The weight of the visceral organs from rats housed at 18°C was higher (P<.05) than at 28°C. The empty weight of the small intestine, caecum and colon increased (P <.05) as the level of pea fibre was increased. The digestibility of DM, protein and dietary fibre (DF) was lower (P <.05) at 18°C than at 28°C. As the level of pea fibre was increased, the digestibilities of nutrients and energy decreased (P <.05). However, the digestibility of DF increased (P <.05) as the level of pea fibre was increased. The partial digested energy value for pea fibre was 11.9 kJ g^?1. The metabolizable energy (ME) intake and heat production at 18°C (1128 and 974 kJ (W^0.75 day)^?1 respectively) were higher (P<.05) than at 28°C (831 and 674 kJ (W^0.75 day)^?1 respectively). As the level of pea fibre was increased, ME intake (W^0.75 day)^?1 and heat production (W^0.75 day)^?1 decreased (P <.05). Heat production as a percentage of ME was higher (P <.05) at 18°C than at 28°C: 86.6% and 81.2%, respectively. Heat production as a percentage of ME was higher (P <.05) for rats fed the 100 g pea fibre kg^?1 diet than the 200 or 300 g pea fibre kg^?1 diet. In conclusion, environmental temperature as well as DF influenced digestive tract and visceral organ size, digestion and protein and energy metabolism.     

Emission characteristics on nature gas engine by additional injection of hydrogen peroxide into the premix chamber

In order to improve combustion efficiency of natural gas(NG) and reduce pollution emission in nature gas engine, additional injection of hydrogen peroxide (H2O2) into the premix chamber is proposed. With the test of CO, HC and NOx concentration, exhaust temperature, NG consumption etc., it is found that the emission of HC、CO and NOx decreased and the dynamic and economic performance of CNG engine is improved. H2O2 can make reduction of the combustion temperature while increase of the oxygen concentration. The pivot factors affecting NOx emission are temperature and oxygen concentration. The optimum mass proportion of nature gas and H2O2 is between 4.5 and 5.8 for NG consumption and pollution emission.