Hydrolytic Degradation of Triacylglycerols and Changes in Fatty Acid Composition in Rice Bran During Storage

Hydrolytic rancidity makes rice bran unsuitable for human consumption, restricting its use to animal feed. To better understand this lipolytic process, bran from rice cultivars ‘Cypress’ and ‘Earl’ differing in oil concentration (23.5 and 18.3 mg of triacylglycerol/100 mg of bran, respectively) was stored at room temperature for five months, and the changes in triacylglycerol content and fatty acid composition, as well as the accumulation of free fatty acids (FFA) were followed. The decomposition of triacylglycerols displayed a decay pattern, with Cypress showing a more elevated degradation rate when compared with Earl. At day 36, both lines reached the same oil concentration, but the triacylglycerol decomposition in Cypress was still higher, indicating that oil concentration may not be a significant factor affecting the intensity of the rancidity process. The higher degradation rate observed in Cypress was apparently caused by higher lipase activity, which was 26% higher (P < 0.001). Fatty acid composition of triacylglycerols changed during storage, the palmitic acid percentage was similarly reduced in both lines to ≈80% of its initial concentration. Oleic and linoleic acids remained almost unmodified or slightly increased. The final content of FFA was ≈58% higher in Cypress than in Earl (P < 0.001). In conclusion, lipase activity appears to be an important factor determining the intensity of the hydrolytic process, but further research is required to confirm this conjecture. If this hypothesis is verified, a selection for lower lipase activity could be useful for increasing rice bran stability.     

节杆菌AD26的分离鉴定及其与假单胞菌ADP对阿特拉津的联合降解

用富集培养法,从农药厂的工业废水中分离到高效降解除草剂阿特拉津的AD26菌株,通过16SrRNA基因序列分析,该菌株被鉴定为节杆菌（Arthrobacter sp.）。降解基因的PCR分析表明,AD26含有阿特拉津降解基因trzN和atzBC,它能以阿特拉津为唯一氮源、蔗糖或柠檬酸钠为碳源生长,将阿特拉津降解成氰尿酸,降解速度快但降解不完全。假单胞菌（Pseudomonas sp.）ADP是Wackett实验室分离的阿特拉津降解菌株,含有阿特拉津降解基因atzABCDEF,能以阿特拉津为唯一氮源、柠檬酸钠为碳源（不能以蔗糖为碳源）生长,将阿特拉津降解成NH3和CO2,降解完全但降解速度慢。在阿特拉津浓度为200mg·L^-1的无机盐培养基中进行的AD26和ADP混合培养表明,它们对阿特拉津的降解发生了互补和增强作用,两个菌株能在以阿特拉津为唯一氮源、蔗糖为碳源的培养基中生长,而且生长和降解速率都好于单个菌株,培养72h后阿特拉津去除率达到99.9%,其中76.7%的阿特拉津被降解成NH3和CO2。这表明由节杆菌AD26和假单胞菌ADP组成的混合菌株在阿特拉津废水处理和污染土壤的生物修复中有很好的应用潜力。     

溴苯腈降解菌株Pseudomonas sp.BX-1的分离鉴定及降解特性研究

为解决溴苯腈残留问题,采用连续富集传代培养的方法,从长期生产溴苯腈的农药厂污染土壤中分离筛选到1株溴苯腈降解菌株BX-1。经过形态学特征、生理生化特征和16S rRNA基因序列系统发育分析,将菌株BX-1鉴定为假单胞菌属(Pseudomonas)。菌株BX-1能以溴苯腈为唯一碳源生长,能在40h内将50 mg·L-1的溴苯腈完全降解,其降解溴苯腈的最适温度为30℃,最适p H值为7.5。0.1m M Fe2+能轻微地促进菌株BX-1降解溴苯腈,而Hg2+能强烈抑制该降解过程。此外,菌株BX-1对溴苯腈的降解效果与起始接种量呈正相关。借助MS/MS鉴定出菌株BX-1降解溴苯腈的中间代谢产物为3,5-二溴-4-羟基苯甲酸和2,6-二溴苯酚。该研究结果为全面阐释溴苯腈的微生物降解机制和溴苯腈污染土壤的生物修复提供了新的种质资源。     

丙酸睾酮对三疣梭子蟹氨基酸和脂肪酸组成的影响

为研究丙酸睾酮(TP)对三疣梭子蟹氨基酸和脂肪酸组成的影响,试验以三疣梭子蟹I期幼蟹为材料,随机分为对照组(饲料中无丙酸睾酮)、TP 200处理组(饲料含200 mg·kg^-1TP)和TP 400处理组(饲料含400 mg·kg^-1TP),养殖90 d后,采用液相色谱质谱联用法检测血清TP、睾酮(T)和雌二醇(E₂)含量,并测定各组生长指标及存活率,检测肌肉和肝胰腺的基本营养成分、氨基酸及脂肪酸组成。结果显示,三疣梭子蟹血清中性激素含量较高,表明其具有较强的性激素富集能力。添加TP对三疣梭子蟹肝胰腺指数及蜕壳频率无显著影响,但成活率显著降低(P<0.05),TP 200组三疣梭子蟹的增重率、特定生长率及全甲宽等指标显著高于对照组及TP 400组(P<0.05)。TP 200组和TP 400组的总氨基酸、必需氨基酸含量与对照组相比无显著差异,但精氨酸含量显著降低(P<0.05)。TP 200组和TP 400组肌肉脂肪酸组成和含量与对照组相比无显著差异,但肝胰腺中部分脂肪酸特别是高度不饱和脂肪酸(C20∶2...     

琉璃苣种子发育过程中脂肪酸成分的变化

为探讨琉璃苣种子发育过程中脂肪酸合成的变化规律,采用脂肪酸甲酯气相色谱法(GC-FAME)对琉璃苣种子发育过程中脂肪酸成分的相对含量进行测定。结果表明,琉璃苣种子主要含有棕榈酸、硬脂酸、油酸、亚油酸、γ-亚麻酸、α-亚麻酸、花生一烯酸和芥子酸等8种脂肪酸成分;成熟种子不饱和脂肪酸成分占总脂肪酸的84.05%,其中亚油酸最高(38.20%),γ-亚麻酸次之(24.59%);随着种子发育,棕榈酸、硬脂酸和α-亚麻酸的相对含量不断下降,其它不饱和脂肪酸成分的相对含量不断增加;棕榈酸与α-亚麻酸呈显著正相关,二者与其它脂肪酸成分呈负相关。本研究结果为进一步揭示琉璃苣种子脂肪酸的代谢及其调控机制提供了数据支持。     

Nutritional Effect of Flaxseeds on Cholesterol Profile and Fatty Acid Composition in Egg Yolk

This experiment investigated the effect of a supplementary dietary source (flaxseed) on egg yolk cholesterol contents and fatty acid profile. Flaxseeds at three different levels (5, 10, and 15%) were supplemented to 84 Rhode Island Red × Fayoumi cross layers during 21–24 weeks of age. The birds were divided randomly into four groups. Flaxseeds were supplemented in the diet at the level of 5% (FS‐5), 10% (FS‐10), and 15% (FS‐15), and one group served as the control (FS‐0). Cholesterol content of eggs was not significantly affected by flaxseed. The amount of monounsaturated fatty acids was significantly decreased with the increase in the flaxseed level, and the highest reduction was observed in FS‐15. The highest total polyunsaturated fatty acid (PUFA) and total omega‐3 PUFA were recorded in FS‐15. These findings reflect that unsaturated healthy fatty acid content in poultry eggs can be increased with dietary supplementation of flaxseed.     

Isolation and Identification of Achromobacter sp. DN-06 and Evaluation of Its Pyridine Degradation Kinetics

Water, Air, &; Soil Pollution - We report the isolation of a new bacterium species (named as DN-06) that degrades pyridine, a model compound containing both carbon and nitrogen, from the aerobic...     

Effect of Extrusion Cooking on Extractable Lipids and Fatty Acid Composition in Sifted Oat Flour

Sifted oat flour was processed at 25.0, 27.5, and 30.0% moisture content in a twin-screw extruder at screw speed 300 rpm. The preset temperatures of the extruder barrel were 120, 150, or 180°C. Raw material and extrudates were analyzed for the content of diethyl ether-extractable lipids, with and without hydrolysis, and the content of chloroformmethanol-water saturated butanol (C/M/WSB) extractable lipids. The lipid extracts were analyzed for fatty acid (FA) composition. Percentage distribution of palmitic, oleic, and linoleic acids were significantly different in the different lipid extracts. Extrusion processing influenced the amounts of extractable lipids, while FA composition was not affected.     

大庆市土地退化时空变化及驱动力分析

以不同时段遥感影像为主要数据源,在GIS软件的支持下,提取了大庆市沙化土地和盐碱地的面积.分析了大庆市土地退化的时空变化格局以及多年平均降水量、干燥度及≥10 ℃积温等自然控制因子对土地退化的影响.运用多元回归方法及主成分分析方法,分析了土地退化与各社会经济因子之间的相关程度及影响土地退化的主导因子,并建立了土地退化驱动因子的诊断模型.研究结果表明,大庆市退化土地面积持续增加,区域变化也比较明显;退化土地年变化率在降水量400 mm,干燥度为1.14,≥10 ℃积温为2 780 ℃处变化最为显著;在社会经济因子中耕地面积数量、原油产量、人E1数量是导致土地退化的主导因素.     

摘除卵巢对母山羊肾周脂肪中脂肪酸组成及相关基因mRNA表达量的影响

公羊去势(摘除睾丸)作为一项十分成熟的生产技术,在畜牧生产上得到了非常广泛的应用,但是有关母山羊(Capra hircus)去势的研究还不多。本研究旨在探讨去势对母山羊血清中血糖、甘油三酯、总胆固醇水平,肾周脂肪组织中脂肪酸的组成以及对乙酰Co A羧化酶(acetly-Co A carboxylase,ACC)、脂肪酸合成酶(fatty acid synthase,FAS)、脂蛋白酯酶(lipoprotein lipase,LPL)和激素敏感酯酶(hormone sensitive lipase,HSL)基因表达的影响。将体重相近的5月龄母山羊摘除卵巢后测定其血糖、甘油三酯、胆固醇水平;采用Agilent-6890N气相色谱仪测定其肾周脂肪组织中脂肪酸的组成;利用实时荧光定量PCR(q RT-PCR)相对定量方法检测FAS、ACC、LPL和HSL m RNA的相对表达量。结果表明,摘除卵巢后,母山羊血清中血糖、甘油三酯和总胆固醇水平较对照组均无显著性差异(P0.05),而且在整个实验过程中保持稳定;肾周脂肪组织中总饱和脂肪酸和4种饱和脂肪酸(SFA)(癸酸(C10∶0)、十五碳酸(C15∶0)、棕榈酸(C16∶0)和木质素酸(C24∶0))的比例(P0.05或P0.01)显著降低;肾周脂肪中总单不饱和脂肪酸(MUFA)和总多不饱和脂肪酸(PUFA)的比例与对照组差异不显著(P0.05),但是表现出了一种上升的趋势,油酸(C18∶1)比例显著上升(P0.05);脂肪酸代谢相关基因中LPL m RNA表达量显著提高(P0.05),ACC和FAS基因的表达量极显著提高(P0.01),HSL基因的表达量显著降低(P0.05)。摘除卵巢不会打破母山羊血清中血糖、甘油三酯、总胆固醇的平衡,可能通过影响肾周脂肪组织中脂肪酸代谢相关基因(FAS,ACC,LPL和SHL)m RNA的表达,降低肾周脂肪中饱和脂肪酸的比例,有利于改善羊肉的风味。本研究结果为揭示摘除母山羊卵巢改善肾周脂肪中脂肪酸的构成提供基础资料。     

饲粮中不同油脂对生长鸡组织脂质含量及其脂肪酸组成的影响

试验选用 4周龄来航鸡雄雏研究饲粮中添加含不同饱和度和双键位置的脂肪酸的油脂对生长鸡组织脂质成分含量及其脂肪酸组成的影响。结果表明 :与饲粮中添加 6%富含软脂酸( 16:0 )和油酸 ( 18:0 n 9)的棕榈油 ( 1组 )比较 ,添加 6%的富含亚油酸 ( 18:2 n 6)的红花油 ( 2组 )、 6%的富含 α-亚麻酸 ( 18:3n 3)的亚麻油 ( 3组 )、 3%的红花油 +3%的亚麻油( 4组 )以及 3%的亚麻油 +3%的富含二十碳五烯酸 ( 2 0 :5n 3,EPA)和二十二碳六烯酸 ( 2 2 :6n 3,DHA)的鱼油 ( 5组 )不同程度地降低鸡肝脏和血清胆固醇酯、游离胆固醇和磷脂的含量 ;富含 n 3系列多不饱和脂肪酸 ( n 3PUFA)的油脂 (亚麻油和鱼油 )还降低鸡肝脏和血清三酰甘油的含量 ,显示出比富含 n 6系列多不饱和脂肪酸 ( n 6PUFA)的油脂 (红花油 )更强的降血脂效果。肝脏、血清脂质成分和腹脂的脂肪酸组成受饲粮油脂脂肪酸组成的影响 ,与棕榈油比较 ,富含 PUFA的油脂可降低软脂酸和单不饱和脂肪酸 (油酸 )的比例、提高 PUFA的比例 ;与红花油比较 ,富含 n 3PUFA的亚麻油和鱼油可降低 n 6PUFA (亚油酸和花生四烯酸 )的比例 ,增加 n 3PUFA ( α-亚麻酸和 EPA)的比例 ;亚麻油中的 α 亚麻酸在体内可能转化为长链 n3PUFA,然而鱼油中的长链 n 3PUFA ( EPA和 DH     

假单胞菌Nwu1-mu对陕北石油污染土壤的生物修复作用研究

选用假单胞菌Nwu1-mu对陕北地区石油污染土壤进行生物修复。通过检测修复过程中土壤样品的菌体生长数量、脱氢酶活性、表面张力和石油烃及其组分降解率综合考察了菌株对石油烃类物质的降解作用。结果表明,在不添加营养物质的前提下假单胞菌Nwu1-mu在60d内对石油污染土壤中的石油烃类物质降解率达到了86.5%,尤其对石油烃中的C24～C28和〉C28组分有突出的降解效果;菌株产脱氢酶和表面活性剂显示出了良好的性能,在石油烃类物质的降解过程中均起着关键的促进作用。假单胞菌Nwu1-mu显示出的强大的生物修复潜力及其不依赖于外来营养源的特性,为黄土高原的土壤生态环境修复提供了新的解决思路。     

Bioremediation of Pulp and Paper Mill Effluent by Tannic Acid Degrading Enterobacter sp.

Wastewaters from pulp and paper mills are highly toxic and around 250 xenobiotic compounds have been reported in the effluents. Tannic acid degrading bacterium, Enterobacter sp. was isolated from soil by tannic acid enrichment. This isolate was used for bioremediation of pulp and paper mill effluents. Parameters like temperature, agitation, inoculum size and treatment duration were optimized by using Qualiteck-4 software. Reduction in lignin 73% and colour up to 82% was also observed. Encouraging results were observed is reduction of COD, BOD with 16-h retention time in batch culture.     

脂肪酸合成酶基因在皮下脂肪中表达及其与血清Leptin的关系

动物的体脂沉积所需要的脂肪酸大多是来自脂肪酸的全程合成,即由脂肪酸合成酶(FAS)催化乙酰辅酶A和丙二酸单酰辅酶A合成甘油三脂(TAG)(Simith et al.,2003)。FAS表达水平的升高显著增加甘油三脂在体内的沉积而导致肥胖(Semenkovich,1997)。leptin是ob基因表达产物,是一种能调节     

Changes in the Amino Acid Composition of Decomposing Plant Materials in Soil: Species and Depth Effects

Abstract

This project studied the amino acid composition of samples taken from an experiment of in situ incubation of plant debris, mixed with mineral earth, to identify changes during decomposition. Medicago sativa debris, and Eucalyptus globulus and Pinus halepensis ground litter, were mixed with a OM‐poor mineral earth, and buried in the soil at 5, 20, and 40 cm depth, for 2 years. The total amino acid composition of the final samples was compared with that of the initial ones. The amino acid composition of the several initial mixtures was quite similar. Also, the differences between initial and incubated samples were small, but still large enough to detect consistent changes. The pattern of change was consistent for only nine amino acids: Gly consistently increased, whereas Lys, His, Leu, and (to a lesser extent) Arg, Tyr, Phe, Ser, and Tau consistently decreased. The ratio Gly/(Lys+His+Leu+Arg+Tyr+Phe+Ser) is taken as the amino acid signature (AaS). This ratio increased from about 0.30–0.35 in the undecomposed mixtures, to about 0.55–0.60 after 2 years of field decomposition, and the comparison with data from other authors suggests that it could be a useful indicator of the degree of biochemical evolution of nitrogen compounds in soil samples. In contrast, changes in the traditional groups of amino acids, i.e., acid, basic, neutral, and sulfur (S)‐containing, were hardly detectable.     

亚东黑耳的氨基酸特征分析及蛋白质品质评价

亚东黑耳(Exidia sp.)是一种尚未实现人工栽培的珍稀食用菌,为发掘和利用其营养价值,在现行国际氨基酸模式谱的基础上,以氨基酸评分(AAS)、美国国家科学院医学研究所(IOM)模式评分、化学评分(CS)、氨基酸比值系数(RC)、氨基酸比值系数分(SRC)和必需氨基酸指数(EAAI)等多个参数为指标,系统地分析了亚东黑耳的氨基酸特征和蛋白质品质。结果表明,亚东黑耳中含有18种常见氨基酸,包括全部8种必需氨基酸;其粗蛋白含量与粮食作物接近,蛋白质中必需氨基酸含量充足(473.4 mg·g^-1 pro),其中亮氨酸含量较高(67.73 mg·g^-1 pro)。参数评估表明,亚东黑耳蛋白质中的必需氨基酸比例相对合理(RC值0.74～1.66,EAAI值129.11),基本符合国际推行的氨基酸平衡模式谱(AAS值均高于98.75%,IOM模式评分均高于100%),是相对优质的蛋白质,但其平衡性和含量均逊色于鸡蛋蛋白(CS值70.93%～128.30%)。本研究结果为进一步开发野生菌资源提供了科学基础。     

不同载体材料固定Sphingobium sp. PHE3对溶液中菲的降解研究

以蒙脱石、针铁矿、玉米秸秆炭为载体,采用吸附挂膜法对菲降解菌株（革兰氏阴性菌鞘脂菌PHE3）进行固定化,并应用固定化微生物降解溶液中的菲。根据扫描电镜结果,该菌株在玉米秸秆炭载体表面附着生长数量最多,形态最优。添加蒙脱石和玉米秸秆炭显著（P<0.05）提高了微生物对菲的降解率,加快了菲的微生物降解速率,同时促进了细菌胞外聚合物（EPS）中多糖和蛋白质产量的增加,但添加针铁矿对菲的微生物降解和EPS的产生促进作用较弱。此外,鞘脂菌PHE3在形成生物膜的过程中可能有群体感应现象发生,能够分泌信号分子C8-HSL和C12-HSL,可能在一定程度上调控EPS的生成和污染物的降解。     

Characterization of Burkholderia sp. XTB‐5 for Phenol Degradation and Plant Growth Promotion and Its Application in Bioremediation of Contaminated Soil

A key issue when researching land degradation is the pollution of soils. For bioremediation of contaminated soil, Burkholderia sp. XTB‐5 cells were obtained from soil and grown on mineral salt medium with initial phenol concentrations of 650 mg L⁻¹ and 850 mg L⁻¹, which were found to degrade more than 98% of phenol content in less than 4 days. About 90% of phenol content (with initial concentration of 250 mg kg⁻¹ soil) was removed from soil inoculated with XTB‐5 cells in 6 days. More than 90% of phenol content was removed within 20 days after co‐introduction of XTB‐5 cells and plants to sterilized soil in a greenhouse or to natural soil in field trials. But under the same conditions, individual introduction of plants to sterilized soil in the greenhouse reduced phenol content by about 50% and introduction to natural soil in field trials reduced phenol content by about 38%, suggesting that phytoremediation of phenol is often inefficient and microorganisms can efficiently degrade this pollutant. In addition, strain XTB‐5 was found to solubilize phosphate and produce 1‐Aminocyclopropane‐1‐Carboxylate (ACC) deaminase and siderophore. Strain XTB‐5 promoted plant growth in both phenol‐absent and phenol‐spiked soil under greenhouse and field conditions. Considering that ACC deaminase is beneficial to plant growth under adverse environmental conditions, plant growth promotion by XTB‐5 in phenol‐contaminated soil is not only due to XTB‐5 cell‐degradation of phenol and reduced phytotoxicity but also to production of ACC deaminase. Hence, Burkholderia sp. XTB‐5 presents an attractive microorganism for phytoremediation of contaminated soil and agronomic application. Copyright © 2016 John Wiley & Sons, Ltd.     

哈夫尼菌降解毒死蜱条件的优化及动力学模型建立

利用响应面法优化哈夫尼菌降解毒死蜱的条件,并建立了降解模型。采用Box-Behnken设计试验,以响应面法进行优化,结果表明,哈夫尼菌降解毒死蜱的最优条件为：蔗糖浓度0.31%,毒死蜱初浓度51.33mg·L-1,培养温度30.7℃,在该条件下理论预测毒死蜱降解率可达74.7%。通过假设和验证,得出哈夫尼菌降解毒死蜱为一级动力学模型,哈夫尼菌能水解毒死蜱P-O键,属一级酶促反应。     

Biodegradation of the Anionic Surfactant Linear Alkylbenzene Sulfonate (LAS) by Autochthonous Pseudomonas sp.

Anionic surfactants, the earliest and the most common surfactants in detergent and cosmetic product formulations contribute significantly to the pollution profile of the ecosystem. Linear alkylbenzene sulfonates (LAS), a major chemical constituent of detergents, forms an imperative group of anionic surfactants. Bioremediation of LAS by conventional processes such as activated sludge is ineffective due to the low kinetics of degradation by unsuitable organisms and foam production. Hence this study was focused on isolating and characterizing indigenous LAS-degrading bacteria from soil. Twenty different LAS-degrading bacteria were isolated from detergent-contaminated soil by enrichment culture technique and degradation efficiency was assessed by Methylene Blue Active Substances (MBAS) assay and by reverse-phase high-performance liquid chromatography (HPLC) analysis. The most efficient LAS-degrading isolates, L9 (81.33?±?0.7) and L12 (81.81?±?0.8), were selected and identified as Pseudomonas nitroreducens (MTCC 10463) and Pseudomonas aeruginosa (MTCC 10462). The 16S rDNA sequences of the isolates were deposited in NCBI GenBank under the accession numbers HQ 271083 (L9) and HQ 271084 (L12). The isolates were capable of degrading 0.05?g/l LAS at 25?°C and pH 7.0?C7.5. Presence of a solid support caused biofilm formation which in turn enhanced LAS degradation. The isolates tend to display diauxic growth with alternate carbon source such as dextrose. These isolates also have the capability to degrade other xenobiotics like hydrocarbons and pesticides. Since xenobiotic pollutants in nature occur as a mixture of compounds rather than single pollutants, the potential of these two indigenous LAS-degrading isolates to degrade multiple xenobiotics gains relevance.