Volatile Organic Compounds in Uremia

Background

Although “uremic fetor” has long been felt to be diagnostic of renal failure, the compounds exhaled in uremia remain largely unknown so far. The present work investigates whether breath analysis by ion mobility spectrometry can be used for the identification of volatile organic compounds retained in uremia.

Methods

Breath analysis was performed in 28 adults with an eGFR ≥60 ml/min per 1.73 m², 26 adults with chronic renal failure corresponding to an eGFR of 10–59 ml/min per 1.73 m², and 28 adults with end-stage renal disease (ESRD) before and after a hemodialysis session. Breath analysis was performed by ion mobility spectrometryafter gas-chromatographic preseparation. Identification of the compounds of interest was performed by thermal desorption gas chromatography/mass spectrometry.

Results

Breath analyses revealed significant differences in the spectra of patients with and without renal failure. Thirteen compounds were chosen for further evaluation. Some compounds including hydroxyacetone, 3-hydroxy-2-butanone and ammonia accumulated with decreasing renal function and were eliminated by dialysis. The concentrations of these compounds allowed a significant differentiation between healthy, chronic renal failure with an eGFR of 10–59 ml/min, and ESRD (p<0.05 each). Other compounds including 4-heptanal, 4-heptanone, and 2-heptanone preferentially or exclusively occurred in patients undergoing hemodialysis.

Conclusion

Impairment of renal function induces a characteristic fingerprint of volatile compounds in the breath. The technique of ion mobility spectrometry can be used for the identification of lipophilic uremic retention molecules.     

天韭挥发性有机化合物成分初步研究

采用动态顶空气循环采集法采集天韭挥发物,通过热脱附-气相色谱/质谱联用法分析其挥发物的化学成分.结果表明,共检测到天韭挥发物成分36种,其中萜烯类化合物12种,苯酚类化合物9种,醛酮醇类化合物6种,烷烃类化合物6种,脂类化合物3种.     

Toxicity Assessment of Volatile Organic Compounds in Poplar Trees

A method is described to assess the toxicity of selected volatile organic compounds (VOCs) in poplar trees. The method is illustrated for a specific aqueous mixture of VOCs that contaminates the groundwater at a site for which phytoremediation was being considered. The VOC mixture contained a variety of aromatic compounds, chlorinated aliphatics, and alcohols. Poplar tree cuttings planted in 50-gallon barrels in the greenhouse were watered via subirrigation. The subirrigant contained either a low (42 mg/L), medium (85 mg/L), or high (169 mg/L) dose of the VOC mixture, or water only (experimental control). Phytotoxicity was evaluated by measuring the physiological parameters of stomatal conductance, shoot elongation, and biomass production. Two experiments are briefly described: (1) The poplar tree cuttings were allowed to become established in the barrels and then treated to gradually increasing concentrations of the VOC mixture until the final dose was reached. The objective was to establish a detailed dose-response relationship. (2) The poplar tree cuttings were given the low, medium, or high dose of the VOC mixture immediately after planting. The aim of this experiment was to determine if the VOC mixture would be inhibitory to root development. Phytotoxic effects were not observed in either experiment.     

植物挥发性物质与植物抗病防御反应

植物挥发性物质的许多组分具有抗菌活性,这可能是其抵御植物病原菌侵染的化学防卫因素;其中一些组分为防卫基因表达的高效调节子,是病原菌侵染植物过程中,植株自身或相邻植株间传递信息的信号分子.该文就植物挥发性物质的主要类群、生理作用、病原菌侵染和其他因子诱导对其影响及其在植物抗病防御反应中的作用作了介绍.     

植物挥发性有机物合成研究进展

植物挥发性有机物与人类生产和生活密切相关。在农业研究方面,植物挥发性有机物具有吸引传粉昆虫,抵御生物和非生物胁迫,介导作物之间信息交流,赋予果实特征风味等重要作用。综述了萜类化合物、苯/苯丙烷类化合物、脂肪酸衍生物和氨基酸衍生物等4类挥发性有机物的合成研究现状,并提出了今后应开展的工作与方法,旨在为进一步开展本领域研究提供有用信息。     

Double Emulsions Stabilized by Food Biopolymers

Double emulsions of the water-in-oil-in-water (W/O/W) type have application in the formulation of reduced-fat food products and as vehicles for encapsulation and delivery of nutrients during food digestion. Progress in the development of stable double emulsions for food use is dependent on replacing small-molecule emulsifiers and synthetic polymeric stabilizing agents by food-grade ingredients. Of particular value for conferring the required functionality are food proteins and polysaccharides. This review describes how these biopolymers have been successfully incorporated into the internal and external aqueous phases of W/O/W emulsions to improve the stability and yield of model systems. Recent advances in the use of protein–polysaccharide conjugates and complexes for the stabilization of the outer droplets of W/O/W emulsions are highlighted.     

Volatile Organic Compounds: Upcoming Role in Diagnosis of Invasive Mould Infections

Purpose of Review

Breath testing for fungal respiratory infections has great promise as samples can be obtained by non-invasive, repeatable techniques that can be done on a wide range of patients including children, the confused and from those in the intensive care unit (ICU). We have reviewed progress toward development of test applicable to clinical practice.

Recent Findings

Many volatile organic compounds (VOCs) have been identified, especially from key pathogens such as Aspergillus fumigatus, but very few clinical trials have been performed. The most convincing of these demonstrated that Aspergillus species could be identified by gas chromatography with mass spectrometry in breath samples of at risk patients with high sensitivity (94%) and specificity (93%) compared with the European Organization for Research and Treatment of Cancer/Mycosis Study Group (EORTC/MSG) gold standard.

Summary

Significant progress has been made but further studies are needed to validate these recent findings and identify VOCs from other pathogenic fungi using GC-MS, and clinical trials performed using faster and less demanding analytic platforms that could be used in clinical laboratories.

     

Volatile Organic Compounds and Their Roles in Bacteriostasis in Five Conifer Species

In order to make clear the functions of plant volatile organic compounds (VOCs) on bacteriostasis and air decontamination, we analyzed the composition and content of VOCs in Pinus tabulaeformis Carr., P. bungeana Zucc., Sabina chinensis Antoine, Picea koraiensis Nakai, and Cedrus deodara G. Don under near-natural conditions using the thermal-desorption cold trap gas chromatography/mass spectrometer technique. The effects of the VOCs on airborne microorganisms were investigated using the method of natural sedimentation. Results showed that the major VOCs were as follows: limonene, β-pinene, α-pinene,and α-caryophyllene in Pinus tabulaeformis and P. bungeana; limonene, borneol acetate, β-pinene, myrcene,and tricylene in S. chinensis; limonene, α-pinene, myrcene, camphene, and β-pinene in Picea koraiensis;and limonene, 2, (10)-pinene, α-pinene, and myrcene in C. deodara. These VOCs and the corresponding foliar extracts inhibited the growth of bacteria and stimulated the growth of fungi. Experimental data using monomers of the VOCs demonstrated that limonene, β-pinene, and three aldehydes could significantly inhibit bacterial growth, suggesting an inhibitory effect of VOCs on the growth of airborne microorganisms in the five conifer species. The bacteriostasis and air-decontaminating effects of plant VOCs are further discussed in terms of their chemical composition.     

Volatile Organic Compounds Associated with Microbial Growth in Automobile Air Conditioning Systems

Volatile organic compounds from Penicillium viridicatum and Methylobacterium mesophilicum growing on laboratory media and on component materials of automobile air conditioners were analyzed with gas chromatography and mass spectrometry. P. viridicatum produced compounds such as 4-methyl thiazole, terpenes and alcohols, whereas M. mesophilicum produced dimethyl disulfide, dimethyl trisulfide, and chlorophenol with growth on laboratory media. In comparison with laboratory media, fewer volatiles were detected from colonized foam insulation materials. Biofilms of M. mesophilicum on aluminum evaporator components produced mainly dimethyl disulfide. These biofilms, after inoculation with P. viridicatum, produced offensive smelling alcohols and esters such as 2-methyl propanol, 3-penten-2-ol, and the ethyl ester of butanoic acid. The moisture and substrates innate to the automobile air conditioning systems provided an environment suitable for microbial biofilm development and odor production. Reduction of retained moisture in the air conditioning system coupled with use of less susceptible or antimicrobial substrates are advised for remediation of the noxious odors. Received: 26 February 2000 / Accepted: 2 May 2000     

番茄几种挥发性组分对番茄灰葡萄孢的抑制作用

采用孢子悬滴培养法,测定番茄几种挥发性组分对番茄灰葡萄孢(Botrytiscinerea)孢子萌发及菌丝生长的抑制作用。结果表明各挥发性组分对灰葡萄孢均有抑制作用,抑制率的大小依次为挥发醛、芳香族化合物和萜类化合物。10μmol/L的(E)-2-己烯醛和壬烯醛可完全抑制孢子萌发和菌丝生长,4μmol/L的丁子香酚和10~20μmol/L的水杨酸甲酯使病菌菌丝异常生长。本研究为番茄挥发性物质在其抗病防御反应中的作用提供理论依据。     

环境因子对植物释放挥发性化合物的影响

对近年来有关环境因子与植物释放挥发性化合物关系的研究进展进行了综合和概括。本文主要包括3类挥发性化合物。⑴异戊二烯是由叶绿体产生并且直接释放到大气中的C5化合物。⑵单萜类化合物是一类环状或非环状的C10化合物,它在植物体内合成后首先贮存于体内的特殊结构中（如树脂道、油腺）,然后由此通过气孔向大气中释放。⑶含氧挥发性化合物以各种形式释放大大气中。它包括醇、醛、酮、酯和有机酸。本文的重点是前两者,主要阐述了二方面内容：⑴植物军发性化合物的生物合成和释放机理。⑵环境因子（如温度、光照、水分胁迫、营养、CO2浓度、空气湿度）及植物的发育阶段、机械损伤和昆虫取食等对植物挥发性化合物合成与释放的影响机制。     

鞭角华扁叶蜂对自然生境柏木挥发物释放的影响

植物挥发物（Volatile organic compounds;VOCs）在植物抵御害虫侵袭的过程中具有重要作用。本研究以重庆市云阳县长江林场人工林中健康和受害柏木为研究对象,通过VOCs测定分析发现鞭角华扁叶蜂虫害发生之前,两种柏木共计有37种VOCs成分,主要为萜类化合物,其次为醇、酯、醛、烷烃等类化合物;其中健康柏木特有驱赶作用的2-莰醇（龙脑）,受害柏木特有吸引作用的顺式-2-癸烯醛,其余35种为共有成分;各成分浓度在两种柏木中存在较大差异。虫害发生之后,两种柏木共计有32种VOCs成分,而2-莰醇、顺式-2-癸烯醛、薄荷醇、臭樟脑和α-石竹烯等5种成分消失;许多成分的浓度变化趋势与虫害发生前的相反。结果表明健康与受害柏木VOCs释放的差异可能是柏木能否抵御鞭角华扁叶蜂侵害的主要防御机制之一,这将为优良抗虫柏木选育提供理论依据和参考指标。     

Binding by Cornstarch of Components of a Mixture of Volatile Organic Substances from Aqueous Solutions

Effects of the composition of a mixture of organic substances on the binding of individual components in aqueous dispersions of native and gelatinized cornstarches with different contents of amylose was studied by capillary gas chromatography. Binding was more active when alcohols were exposed to cornstarch as mixtures rather than individual compounds. In a multiple-component mixture, compounds belonging to distinct classes competed with each other for binding sites. Odorant binding by aqueous starch dispersions was more sensitive to the composition of the mixture and the nature of starch when studied in aqueous dispersions of native starches (compared to those of gelatinized starches).     

顶空及SERS结合快速检测葱属植物-大葱挥发物

建立了常温常压下快速检测新鲜葱属植物-大葱主要挥发性气体的方法。采用顶空瓶在常温常压下收集大葱的挥发物,将挥发物用注射器注入纳米银胶中,进行SERS测量。结果表明大葱的挥发物SERS光谱重现性非常好;将大葱挥发性物的SERS谱与1-丙硫醇(1-Propanethiol)和烯丙基甲基硫醚(allyl methyl sulfide)混合气体的SERS谱相比,具有较好的相似性,说明大葱的挥发物主要由1-丙硫醇和烯丙基甲基硫醚气体组成。利用Gaussian 03软件获得1-丙硫醇-银(1-Propanethiol-Ag)的Raman光谱,计算结果与1-丙硫醇的SERS实验结果对应较好,说明1-丙硫醇在纳米银基底上的增强为化学增强。顶空与SERS结合可直接用于对葱属植物挥发性物的研究。     

Volatile Compounds from Melicope obscura

To evaluate the interpopulation variability of volatile compounds in Melicope obscura, four samples representing four populations were collected all over the distribution area of the species in Reunion Island (Indian Ocean). The samples were extracted by hydrodistillation, and analyzed using GC/FID and GC/MS techniques. The study revealed that, in the four essential oils obtained, oxygenated sesquiterpenes were one of the major chemical classes (9.2–35.2%), mainly consisting of a new compound, (+)‐6‐ethenyl‐2‐hydroxy‐6,10‐dimethylundeca‐2,9‐dien‐4‐one ( 1 ), called melicopenol (8.6–30.1%). The compound was isolated by column chromatography and identified by spectral analyses including 1D‐ and 2D‐NMR.     

Priming of Production in Maize of Volatile Organic Defence Compounds by the Natural Plant Activator cis-Jasmone

cis-Jasmone (CJ) is a natural plant product that activates defence against herbivores in model and crop plants. In this study, we investigated whether CJ could prime defence in maize, Zea mays, against the leafhopper, Cicadulina storeyi, responsible for the transmission of maize streak virus (MSV). Priming occurs when a pre-treatment, in this case CJ, increases the potency and speed of a defence response upon subsequent attack on the plant. Here, we tested insect responses to plant volatile organic compounds (VOCs) using a Y-tube olfactometer bioassay. Our initial experiments showed that, in this system, there was no significant response of the herbivore to CJ itself and no difference in response to VOCs collected from unexposed plants compared to CJ exposed plants, both without insects. VOCs were then collected from C. storeyi-infested maize seedlings with and without CJ pre-treatment. The bioassay revealed a significant preference by this pest for VOCs from infested seedlings without the CJ pre-treatment. A timed series of VOC collections and bioassays showed that the effect was strongest in the first 22 h of insect infestation, i.e. before the insects had themselves induced a change in VOC emission. Chemical analysis showed that treatment of maize seedlings with CJ, followed by exposure to C. storeyi, led to a significant increase in emission of the defensive sesquiterpenes (E)-(1R,9S)-caryophyllene, (E)-α-bergamotene, (E)-β-farnesene and (E)-4,8-dimethyl-1,3,7-nonatriene, known to act as herbivore repellents. The chemical analysis explains the behavioural effects observed in the olfactometer, as the CJ treatment caused plants to emit a blend of VOCs comprising more of the repellent components in the first 22 h of insect infestation than control plants. The speed and potency of VOC emission was increased by the CJ pre-treatment. This is the first indication that CJ can prime plants for enhanced production of defensive VOCs antagonist towards herbivores.