多环芳烃和镉土壤复合暴露条件下黑麦草的氧化应激指标变化

为了探究场地土壤多环芳烃（PAHs）和镉（Cd）在复合污染条件下的植物生物效应,本研究以黑麦草（Lolium perenne L.）为供试植物,采用土培方法进行染毒试验,分析了植物中4种典型氧化应激指标多酚氧化酶（Polyphenol oxidase,PPO）、磷酸烯醇式丙酮酸羧化酶（Phosphoenolpyruvate carboxylase,PEPC）、脯氨酸（Proline,Pro）和还原性谷胱甘肽（Reduced glutathione,GSH）的响应变化。结果表明：单一Cd染毒下,黑麦草的PPO活性呈下降趋势,PEPC活性以及Pro浓度均呈先上升后下降的趋势,GSH浓度呈上升趋势;单一PAHs染毒下,黑麦草的PPO活性呈下降趋势,PEPC活性以及Pro和GSH浓度均呈先上升后下降的趋势。因此,PAHs和Cd的单一污染胁迫下黑麦草生理系统均受到了影响,产生了氧化应激反应。与单一Cd染毒相比,Cd-PAHs复合染毒下,黑麦草的4种指标变化趋势均发生了显著变化（P<0.05）。PEPC和PPO的活性以及Pro和GSH浓度的显著下调可能是场地土壤高浓度PAHs和Cd复合污染的重要指征。在复合染毒胁迫下,黑麦草4种指标普遍呈现拮抗效应。研究表明重金属Cd和PAHs复合污染对典型植物氧化应激效应指标具有剂量-效应关系。     

猕猴桃果汁香气物质的固相微萃取GC/MS分析

为了对猕猴桃果汁加工品质的控制提供科学依据,选用陕西周至县的秦美和眉县的海沃德猕猴桃,榨汁、酶解后取果汁样品,采用固相微萃取法提取、富集果汁中香气物质,经GC/MS分离与分析,共鉴定出120种化合物,其中秦美果汁含有97个组分、海沃德果汁含有101个组分。不同品种果汁中主要香气物质构成种类基本相同,其含量分布存在差异。乙酸乙酯、乙醇、丁酸甲酯、丁酸乙酯、己酸乙酯、乙酸己酯、正己醇、(E)-2-己烯-1-醇等化合物是猕猴桃果汁中的主要香气物质,对猕猴桃果汁特征风味的形成具有重要作用。     

不同晒晾条件下香料烟叶片结构变化规律的研究

首次对塑料大棚内及屋檐下晒晾的香料烟叶片结构变化进行了研究。结果发现,在两种晒晾条件下,叶肉细胞的收缩变化均具有一定规律性,细胞壁先扭曲,然后原生质体解体,最后物质收缩凝聚成网状,网眼为新形成的腔隙;叶片厚度呈不等臂凹曲线形变化;栅栏组织的收缩率小于海绵组织,且随着叶位升高,前者的收缩率明显减小。塑料大棚内晒晾的烟叶与屋檐下晒晾的相比,前者叶肉细胞的原生质体解体较早、较快,晒晾结束凝聚物形成的网状结构网眼小而均匀,香、吃味较好,上等烟的比例大。     

Influences of kaolinite and montmorillonite on benzo[a]pyrene biodegradation by Paracoccus aminovorans HPD-2 and the underlying interface interaction mechanisms

Clay minerals play an important role in biogeochemical cycling. Here, kaolinite and montmorillonite, the two most abundant and widespread clay minerals with typical layered structures, were selected to investigate and compare their effects on the biodegradation of benzo[a]pyrene (BaP) by Paracoccus aminovorans HPD-2 and to investigate the underlying interface mechanisms. Overall, the BaP degradation efficiency was significantly higher 7 d after montmorillonite addition, reaching 68.9% (P < 0.05), when compared with that of the control without addition of clay minerals (CK, 61.4%); however, the addition of kaolinite significantly reduced the BaP degradation efficiency to 45.8%. This suggests that kaolinite inhibits BaP degradation by inhibiting the growth of strain HPD-2, or its strong hydrophobicity and readily agglomerates in the degradation system, resulting in a decrease in the bio-accessibility of BaP to strain HPD-2. Montmorillonite may buffer some unfavorable factors, and cells may be fixed on the surface of montmorillonite colloidal particles across energy barriers. Furthermore, the adsorption of BaP on montmorillonite may be weakened after swelling, reducing the effect on the bio-accessibility of BaP, thus promoting the biodegradation of BaP by strain HPD-2. The experimental results indicate that differential bacterial growth, BaP bio-accessibility, interface interaction, and the buffering effect may explain the differential effects of the different minerals on polycyclic aromatic hydrocarbon biodegradation. These observations improve our understanding of the mechanisms by which clay minerals, organic pollutants, and degrading bacteria interact during the biodegradation process and provide a theoretical basis for increasing the biodegradation of soil pollutants by native microorganisms under field conditions.     

两种砂梨果实香气成分分析及其相关基因PpAAT的克隆与表达分析

梨（Pyrus spp）是深受国内外消费者喜爱的水果,果实香气是果实品质的重要指标,也是吸引消费者和增强市场竞争力的主要因素之一。本文以砂梨品种‘二十世纪’及其芽变品种‘金二十世纪’为试材,研究了其果实不同发育时期香气成分的差异,克隆获得了梨果实香气成分合成相关的醇酰基转移酶基因（PpAAT）,分析了该基因在梨果实不同发育时期及不同部位中的时空表达规律,结果表明：‘二十世纪’绿熟期、商熟期和完熟期果实的主要香气成分均为己醛,‘金二十世纪’绿熟期果实的主要香气成分同样是己醛,但商熟期果实中己酸乙酯的含量迅速增加,成为主要香气成分,完熟期时含量进一步增加,高含量的酯类化合物可能是‘金二十世纪’具有浓郁香气的主要原因;随着果实的成熟,PpAAT基因在‘金二十世纪’果皮中的表达量呈逐渐下降的趋势,绿熟期表达量最高,商熟期表达量开始降低,完熟期表达量非常弱;PpAAT在果肉中的表达量呈先升高后降低的趋势,在商熟期果肉中表达量最高,绿熟期果肉中次之,完熟期果肉中的表达量最低。总体上,PpAAT基因在商熟期的表达量高于绿熟期和完熟期,在果皮中的表达量高于果肉。     

云南紫苏资源芳香油积累动态的研究

应用水蒸汽蒸馏法对收集到的２０份云南紫苏试材的芳香油积累动态进行了研究，结果表明：不同发育时期芳香油含量不同，以花芽分化及开花期含量最高；试材间芳香油含量差异极大，最高者可达０．３０８７％，最低者仅为０．０４３１％。     

草海水体中多环芳烃污染特征及生态风险评价

利用GC-MS测定草海水体15个样品中16种优先控制多环芳烃(PAHs)的含量,分析其组成和来源特征,并进行生态风险评价.结果表明:水体中PAHs总量的变化范围为13.40~694.93 ng·L^-1,平均值为334.73 ng·L^-1,高于太湖、巢湖、鄱阳湖等国控重点湖泊;草海水体中PAHs组成以2、3环为主,占PAHs总体含量的68.59%;空间分布表现为湖心区浓度最低,受附近居民影响较大的近岸区南侧浓度最高.源解析结果显示草海水体中PAHs的主要来源为煤和木材、柴薪等生物质的燃烧,主要通过生活污水排放进入草海.通过风险商值的方法对PAHs的潜在生态风险进行了评价,结果显示PAHs在12个采样点呈现低风险水平,2个中等风险,1个高风险,其中5、6环PAHs的平均风险商值占总体的64.87%.     

千层金油芳香水的化学成分分析

采用GC和GC-MS分析水蒸气蒸馏法提取千层金挥发油的千层金油芳香水中溶于（或微溶于）水的芳香组分,并与千层金油的化学成分进行对比,得出千层金油的主要成分为丁香酚甲醚,含量达90%。千层金芳香水和千层金油样品的主要化学成分基本一致。水蒸气蒸馏法提取千层金挥发油的千层金芳香水可以采用复馏工艺回收溶于水的轻组分以提高得率,也可开发一系列新产品。     

An analysis in support of sediment quality thresholds for polycyclic aromatic hydrocarbons (PAHs) to protect estuarine fish

• 1. Under the US Endangered Species Act and the Essential Fish Habitat provisions of the Sustainable Fisheries Act, it is the responsibility of the National Marine Fisheries Service (NMFS) to safeguard the health of fish in estuarine and coastal waters.
• 2. This includes assessment of the impacts of exposure to toxic chemicals on fish and their critical habitat.
• 3. This analysis was conducted to assist NMFS resource managers in determining when fish are exposed to potentially harmful concentrations of one of the most common environmental contaminants, polycyclic aromatic hydrocarbons (PAHs).
• 4. Effects thresholds were estimated primarily through segmented regression of site‐specific sediment PAH concentrations and associated disease prevalences in a resident fish species, English sole, Pleuronectes vetulus.
• 5. The analyses and supporting data encompass several endpoints, including DNA damage, liver lesions, and impacts on growth and reproduction.
• 6. In general, liver lesion prevalences, DNA adduct levels, and impacts on growth and reproduction were minimal at sediment PAH concentrations at or below 1000 ppb. Above 1000 ppb, there appears to be a substantial increase in the risk of contaminant‐related injury to English sole.

Published in 2002 John Wiley & Sons, Ltd.     

Altered stress responses in rainbow trout following a dietary administration of cortisol and β-napthoflavone

Previous studies have demonstrated that fish inhabiting polluted waterways often have an impaired stress response at the organismal level. Given the possible link between the organismal (i.e. cortisol) and cellular (i.e. heat shock proteins; hsp) stress responses, we conducted this study to examine the ability of rainbow trout to respond to a 2 h, +14 °C heat stress (HS) challenge following a 28 d, sub-chronic exposure to increased concentrations of cortisol (5 mg kg⁻¹ b.w.), β-napthoflavone (bnf; 50 mg kg⁻¹ b.w.), and a combination of both (mixture), through the diet (1.5% b.w. every 48 h). While control fish responded to the HS by significantly increasing components of their organismal (cortisol, glucose, and lactate) and cellular (hepatic hsp70 protein) stress responses 6 and 24 h post HS, cortisol-, bnf-, and mixture-fed fish had impaired stress responses at both levels of organization. Additionally, hepatic hsp70 levels were significantly reduced 6 h post HS in cortisol-fed fish. While bnf-fed fish had significantly higher EROD activity, cortisol potentiated EROD activity in the mixture-fed fish. Similarly, plasma cortisol concentrations in the mixture-fed fish were significantly lower relative to cortisol-fed fish. These data are the first to indicate that sub-chronically stressed fish can have impaired stress responses at both the organismal and cellular levels. These findings raise questions regarding: (a) the universal and simple applicability of biological indicators of stress in fish; (b) the possible functional relationship between these two levels of stress responses; and (c) the importance of hsps in the generalized stress response of the whole organism. This revised version was published online in August 2006 with corrections to the Cover Date.