椰子Acyl-ACP硫酯酶相关基因的克隆及其表达分析

椰子是一种重要的热带油料作物,椰子果成熟后,椰子果肉脂肪酸的主要成分为C12的月桂酸.应用椰子转录组测序的结果,从中挖掘了11个脂酰-ACP硫脂酶基因,分别是2个FatA基因、4个Fat B1基因、3个FatB2以及2个FatB3基因.应用荧光定量PCR检测了Unigene9211、Unigene19303、Unigene45926、Unigene27250以及Unigene22278在果肉形成的3个阶段的表达变化,结果显示,这些基因在果肉形成的3个阶段持续表达.同时,对3个时期的果肉的脂肪酸成分也进行了测定,结果显示,在椰果发育7个月时,中低碳链的脂肪酸含量较低,但随着椰果的发育,中低碳链的脂肪酸逐步增加.     

有机酸类化感物质对甜瓜的化感效应

以甜瓜种质"新银辉"为材料,用苹果酸、柠檬酸、对羟基苯甲酸、肉桂酸、阿魏酸、水杨酸和香豆酸等7种有机酸类化感物质处理甜瓜种子和幼苗,探讨其对甜瓜的化感效应及作用机理。结果表明:苹果酸可以促进甜瓜种子发芽和幼苗胚根生长,抑制植株鲜重增加和胚轴生长;柠檬酸促进发芽,对羟基苯甲酸和肉桂酸抑制发芽,但三者均抑制胚根生长,且对鲜重和胚轴生长表现为低促高抑效应,高浓度肉桂酸对种子发芽和胚轴生长的抑制效应最强,可能是甜瓜重要的化感物质;阿魏酸和香豆酸对发芽表现为低促高抑效应,抑制鲜重、胚根和胚轴生长;水杨酸对发芽和胚轴生长表现为低促高抑效应、抑制鲜重和胚根生长。7种有机酸处理后过氧化物酶活性均增强,有机酸类物质对甜瓜的化感效应可能和其体内的过氧化氢水平有较高的相关性;苹果酸、肉桂酸、对羟基苯甲酸和水杨酸处理后甜瓜幼苗体内超氧化物歧化酶的活性基本呈下降趋势,柠檬酸、阿魏酸和香豆酸则表现为低促高抑效应;过氧化物酶活性变化较复杂,但基本随处理浓度升高而上升;丙二醛含量大多低于对照。     

Effects of Exogenous Humic Acids on Forms of Organic Phosphorus in Three Contrasting Types of Soil

A laboratory incubation study was conducted to examine the effects of exogenous humic acids on the forms of organic phosphorus (P) in three contrasting soil types: red soil, brown soil, and drab soil. Results indicated that the Olsen P concentration increased in all the three types of soil with addition of the humic acid extracts, with the magnitude of increment ranked in a sequence of brown soil > drab soil > red soil. For the soil organic P fractions, addition of the humic acid extracts increased the labile organic P and moderately labile organic P concentrations while reducing the moderately resistant organic P and highly resistant organic P concentrations, suggesting that the exogenous humic acids could enhance transformation of organic P from resistant forms to labile forms. The activation of organic P by addition of the humic acid extracts varied with soil type, and this variation was related to soil characteristics.     

Phytotoxicity of organic acids as influenced by montmorillonite,hydroxy‐Al montmorillonite and phosphate fertilization

Abstract

The germination and growth of wheat seedlings were studied at pH 5.5 in liquid growth media with organic acids in concentrations ranging from 800 to 1200 ppm, before and after interaction of the organic acids with montmorillonite and hydroxy‐Al montmorillonite. Germination was not affected by the organic acids, but subsequent growth was dependent on the kind and concentration of organic acid in the growth medium. Acetic acid was more inhibitory than citric acid. Gallic acid polymerized at pH 5.5 and was phytotoxic at 1200 ppm. Interaction of organic acids with montmorillonite and hydroxy‐Al montmorillonite reduced the concentration of organic acids in solution by adsorption. Despite this reduction in concentration the phytotoxicity of the growth media was enhanced after the interaction. This was caused by the dissolution of surface Al and the effect was more pronounced in cases where hydroxy‐Al interlayered montmorillonite was the adsorbent. Additions of P as KH₂PO₄ alleviated the phytotoxicity of organic acids but not the associated Al toxicity. The amount of P lost by adsorption or precipitation was dependent on the form of Al in the growth media.     

Sesame (Sesame indicum L.) biochemical and physiological responses as affected by applying chemical,biological, and nano-fertilizers in field water stress conditions

Abstract

Co-application of nano, chemical, and biological fertilizers has been recommended to increase quality and quantity of plants in sustainable production systems. Field experiments (factorial split plot experiment based on completely randomized block design) were conducted during two consecutive years to investigate the effect of nitrogen (nitroxin, urea, and nitroxin + 50% urea) and potassium (without fertilizer, soil and foliar application of potassium nano-chelate, and potassium dioxide) forms on grain yield, physiological traits, oil content, and fatty acids composition of sesame under water stress conditions (normal irrigation, irrigation up to 50% seed ripening and flowering (mild and severe stresses, respectively). Severe water stress was caused decreasing chlorophyll content, grain yield (25.4%), seed oil content (2.87%), and unsaturated fatty acid content, while it increased catalase and peroxidase activities, total carbohydrate, and saturated fatty acids content in compared to the control. As shown, the grain yield in the second year was more than the amount in the first year. The highest grain yield was achieved in co-application of 50% urea and nitroxin in combined with potassium dioxide under normal irrigation during the second year, which showed an increase of 42%, compared to the control treatment. Application of potassium fertilizer (nano or chemical) increased unsaturated fatty acids content in compared to the control treatment. While non-application of fertilizer had the highest saturated fatty acids content. Finally, the co-application of potassium fertilizer (nano or chemical forms) with nitrogen fertilizer (nitroxin + 50% urea) could alleviate the adverse effects of water stress on the studied traits.     

缺刻缘绿藻ω3脂肪酸去饱和酶基因(ω3FAD)在酿酒酵母中的低温诱导表达

ω3 脂肪酸去饱和酶(fatty acid desaturase, FAD)能使藻类细胞产生一系列具有高附加值的ω3 脂肪酸。在已克隆到缺刻缘绿藻(Myrmecia incisa Reisigl)的ω3FAD 基因基础上,为进一步了解其功能,本研究首先利用反转录 PCR(RT-PCR)技术,克隆其开放阅读框(open reading frame, ORF)片段,然后亚克隆到穿梭表达载体 pYES2 中,以构建重组酵母表达载体 pY-ω3FAD;通过电穿孔法将该重组载体转入酿酒酵母(Saccharomyces cerevisiae)INVSc1 菌株中,经筛选与序列验证得到含有 pY-ω3FAD 重组质粒的酵母转化株。在 5℃,添加底物亚麻酸及半乳糖诱导表达,连续培养 72 h,经脂肪酸甲酯的气相色谱分析及气相色谱 - 质谱联用证明,转目的基因的酵母能将外源添加的亚油酸在 15 位脱氢生成α- 亚麻酸,表明ω3FAD具有Δ15 脂肪酸去饱和作用的功能。在不同温度条件下诱导培养时,气相色谱结果显示,在 30℃培养的转基因酵母中没有检测到α- 亚麻酸;但在不高于 25℃培养的转基因酵母中,发现ω3FAD 能将外源添加的底物去饱和为α- 亚麻酸,且随着温度的降低,其去饱和能力增强,5℃时的底物转化效率达到29.73%。将转目的基因酵母在 5℃温度下诱导培养不同时间,结果显示,随着培养时间的增加,LA(linoleic acid,亚油酸)转化为α- 亚麻酸的效率也提高,培养 4 d 时其转化效率达到 38.86%。该研究结果提示,缺刻缘绿藻ω3FAD 基因编码的酶蛋白为一个低温诱导酶。缺刻缘绿藻ω3FAD 基因之所以能在酵母细胞中被低温诱导表达,可能因为后者存在一个低温诱导的脂肪酸去饱和系统。     

Determination of Fatty Acid Composition of Turfgrass by High‐Performance Liquid Chromatography

Abstract

The fatty acid composition of warm‐season turfgrasses is physiologically regulated by environmental changes, particularly temperature. Species or cultivars, which have increased degree of unsaturation, usually have a greater freeze resistance. Quantifying fatty acid composition not only can help understand the freeze‐resistant mechanism of warm‐season turfgrasses but also in practice develop a management strategy for better turf. A high‐performance liquid chromatography (HPLC) method was developed for this purpose. The method is based on the bromophenacyl reaction of fatty acids and separation on a C8 column with gradient elution. Information on limit of identification, linearity of quantification, response factor, and derivatization conditions is presented and discussed. The method presented is simple to apply and provides an alternative to the traditional gas chromatography (GC) method. The results of fatty acid composition from a field freezing‐resistance experiment are discussed.     

响应面优化超临界CO2萃取罗非鱼头油的研究

为优化罗非鱼头油的提取工艺,通过单因素试验选择超临界CO2萃取罗非鱼头油的单因素水平,采用响应面法优化超临界CO2萃取罗非鱼头油的工艺条件,分析了罗非鱼头油的品质及脂肪酸组成。结果表明:超临界CO2技术萃取罗非鱼头油的最优工艺条件是压力36 MPa、温度41℃和时间3.1 h,超临界CO2流体技术优于蒸煮法、碱水解法和酶解法;罗非鱼头油的最大提取率是79.5%,其碘值、过氧化值和酸值分别是(5.36±0.15)mg/kg、(4.27±0.33)mmol/kg、(139.0±8.9)g/100g;罗非鱼头油的饱和脂肪酸(saturated fatty acid,SFA)、单不饱和脂肪酸(monounsaturated fatty acid,MUFA)和多不饱和脂肪酸(polyunsaturated fatty acid,PUFA)的含量分别是27.85%,41.74%和30.41%,罗非鱼头油丰富的脂肪酸构成暗示着其优良的营养价值和功能性。     

The oil content and fatty acid composition of various genotypes of cauliflower,turnip and radish

Seeds of thirteen genotypes of cauliflower, four of turnip and seven of radish were analysed for oil content and fatty acid composition. Turnip and radish had higher oil content as compared to cauliflower. Oleic, linoleic + eicosenoic and erucic acids were the major fatty acids in the oils of these seeds. Levels of erucic acid were in the order of radish < turnip < cauliflower. Compared to cauliflower and turnip seeds, radish seeds contained higher amounts of palmitic, oleic, and linolenic + eicosenoic acids and lower amounts of linoleic and erucic acids.