Volatile profiles of human skin cell cultures in different degrees of senescence

It is known that skin releases volatile organic compounds to the environment, and also that its emission pattern changes with aging of the skin. It could be considered, that these compounds are intermediaries in cell metabolism, since many intermediaries of metabolic pathways have a volatile potential. In this work, a simple and non-destructive method consisting of SPME sampling and GC/MS analysis was developed to identify volatile organic emanations from cell cultures. This technique, applied to skin cells culture, indicates that the cells or cell metabolism produce several skin emissions. Chemometric analysis was performed in order to explore the relationship between a volatile profile and the senescence of cell cultures. Volatile profiles were different for cell cultures in different degrees of senescence, indicating that volatile compound patterns could be used to provide information about the age of skin cells.     

Behavioural and electrophysiological responses of the malaria mosquito Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) to human skin emanations

Behavioural and electrophysiological responses of Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) to human skin emanations collected on glass beads were studied using a dual-port olfactometer and electroantannography. Glass beads to which skin emanations from human hands had been transferred elicited a level of attraction similar to a human hand. The attractiveness of these handled glass beads faded away 4 h after transfer onto the beads. Storage at -20 degrees C for up to 8 weeks showed a decreased but still attractive effect of the beads. In a choice test between one individual and four others, the emanations from the reference individual were significantly more attractive in three out of four cases. The headspace of handled glass beads elicited a dose-dependent EAG response. The substances causing EAG activity could be removed partially by dichloromethane, ethanol and pentane-ether. Glass beads provide a suitable neutral substrate for the transfer of human odour to enable chemical analysis of the human skin emanations for identification of kairomones of anthropophilic mosquitoes.     

Solid-phase microextraction and the human fecal VOC metabolome

The diagnostic potential and health implications of volatile organic compounds (VOCs) present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME) has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 μm CAR-DVB-PDMS, 85 μm CAR-PDMS, 65 μm DVB-PDMS, 7 μm PDMS, and 60 μm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein.     

Differential behaviour of Anopheles gambiae sensu stricto (Diptera: Culicidae) to human and cow odours in the laboratory

A dual port olfactometer was used to study the response of Anopheles gambiae Giles sensu stricto to odours of human and animal origin. Human odour consisted of human skin emanations collected on a nylon stocking, which was worn for 24 h. This was tested alone or together with 4.5% carbon dioxide, the concentration in human and cattle breath. Cattle odours consisted of cow skin emanations and/or carbon dioxide. Cow skin emanations were collected by tying a nylon stocking ('cow sock') around the hind leg of a cow for 12 h. Anopheles gambiae s.s. was consistently highly attracted by human odour, which is consistent with the high degree of anthropophily in this mosquito. Anopheles gambiae s.s. was not attracted by human or cattle equivalent volumes of carbon dioxide and this gas did not enhance the effect of human skin residues. Furthermore, A. gambiae s.s. showed a high degree of aversion to cow odour. When human odour and cow odour were tested together in the same port, mosquitoes were still highly attracted, indicating that whilst cattle odour may deter A. gambiae s.s., these mosquitoes can detect human odour in the presence of cattle odour. It was concluded that carbon dioxide plays a minor role in the host seeking behaviour of A. gambiae s.s., whilst host specific cues such as human skin residues play a major role and very effectively demonstrated anthropophilic behaviour in the laboratory.     

松毛虫性信息素的固相微萃取及质谱和触角电位分析

松毛虫性信息素成分在腺体中含量很低。本研究利用固相微萃取（SPME）技术近距离长时间采集单头云南松毛虫Dendrolimus houi处女雌蛾释放的性信息素成分, 并进一步利用气相色谱-质谱（GC-MS）和气相色谱-触角电位联用（GC-EAD）技术分析SPME采集的性信息素成分。 结果显示: 在云南松毛虫处女雌蛾求偶召唤期间SPME聚乙二醇/二乙烯基苯（CAR/DVB）萃取头吸附了大量的反5, 顺7-十二碳二烯醇（E5, Z7-12:OH）和反5, 顺7-十二碳二烯乙酸酯（E5, Z7-12:OAc）成分及微量的反5, 顺7-十二碳二烯醛（E5, Z7-12:Ald）成分, 这3种腺体成分均能激起云南松毛虫雄虫触角电位反应。与溶剂浸提昆虫性信息素成分的方法比较, SPME活体采样技术和GC-MS及GC-EAD分析方法联用研究昆虫的信息素成分具有采集的样品代表性强、样品量能满足色谱分析需要和无溶剂干扰等方面的优点。最后还着重讨论了SPME技术的应用价值、效果及实际应用中应该注意的一些问题。      

Optimization of microwave-assisted extraction followed by solid phase micro extraction and gas chromatography-mass spectrometry detection for the assay of some semi volatile organic pollutants in sebum

Methodology using MAE/SPME/GC-MS is being pursued for the analysis of organic pollutants in sebum. The microwave-assisted extraction (MAE) of standards of semi volatile organic pollutants from sebum was optimized. All compounds were extracted from sebum with recoveries analyzed by GC/MS ranging from 94% to 100% under the optimum MAE conditions: 10mL acetone-hexane (2:1), 60 degrees C, and 10 min microwave heating. To improve the detection limits a SPME procedure was optimized. Linearity ranged from 0.70 ppb to 25 ppb. R.S.D. were in the range of 1-23% for the SPME step. Preliminary real samples were analyzed and a range of compounds was detected. The optimized MAE/SPME/GC-MS methodology promises to be useful for different applications.     

高山被孢霉淬灭方法及胞内代谢产物的气相色谱-质谱分析比较

在花生四烯酸生产菌高山被孢霉代谢组学研究中,需利用胞内代谢物的提取手段并基于气相色谱-质谱（GC-MS）分析方法对其进行检测。比较了3种胞内代谢物提取方法及不同色谱柱条件下GC-MS分析结果。研究表明：采用冷甲醇淬灭分别较液氮直接淬灭及真空过滤后,减少了胞内代谢物的泄露并更好地实现了胞外及胞内代谢物的分离。在对代谢物分析的比较中,极性色谱柱（DB-FFAP）检出的代谢物仅为11种,主要为有机酸、醛类;而代谢物经衍生化后采用非极性色谱柱（DB-5）共检出32种化合物,主要为糖、糖苷及醇类。     

Effect of human odours and positioning of CO2 release point on trap catches of the malaria mosquito Anopheles gambiae sensu stricto in an olfactometer

Abstract.  The anthropophilic malaria mosquito Anopheles gambiae sensu stricto responds to CO₂ and human skin emanations. How these odorants affect the behaviour of this mosquito species is studied in an olfactometer. Carbon dioxide is released either as an homogeneous plume or in a turbulent fashion at two different positions from the trap entrance. Anopheles gambiae is deterred from entering a trap with CO₂ as the only kairomone, when presented as an homogeneous or turbulent plume. This effect is completely overcome by the addition of skin emanations to the CO₂ plume, with a high proportion of mosquitoes found in the trap with skin emanations. Rearrangement of the position of the turbulent CO₂ source so that it is 5 cm downwind of the trap entrance overcomes the deterrent effect of CO₂. Carbon dioxide alone, however, does not elicit higher proportions caught compared with clean air. Further studies with the CO₂ source positioned 5 cm downwind of the trap entrance show that skin emanations alone result in fewer mosquitoes entering the trap than CO₂+ skin emanations. Skin emanations induce more mosquitoes to fly into a trap than a synthetic blend of NH₃+ l-lactic acid when both are combined with CO₂. It is concluded that CO₂ is a poor kairomone when offered alone and that its presence in the plume at the trap entrance deters mosquitoes from entering. By contrast, when positioned just downwind of the trap entrance, CO₂ appears to guide mosquitoes to the vicinity of the trap, where skin emanations then become the principle attractant, causing the mosquito trap entry response. The results of the study have implications for the design of odour-baited traps for this mosquito species.     

Interindividual variation in the attractiveness of human odours to the malaria mosquito Anopheles gambiae s. s

Differences between human individuals in their attractiveness to female mosquitoes have been reported repeatedly, but the underlying mechanisms are not well understood. Skin emanations from 27 human individuals, collected on glass marbles, were tested against ammonia in a dual-choice olfactometer to establish their degrees of attractiveness to anthropophilic Anopheles gambiae s.s. Giles (Diptera: Culicidae) mosquitoes. Ammonia was used as a standard odour source because of its proven attractiveness to An. gambiae s.s. Skin emanations from most volunteers attracted significantly more mosquitoes than ammonia. There were clear differences in the attractiveness of skin emanations from different volunteers relative to that of ammonia, as well as in the strength of the trap entry response. Consistent differences were observed when emanations from the three most and the three least attractive volunteers were tested pairwise. No gender or age effect was found for relative attractiveness or trap entry response. Emanations from volunteers with higher behavioural attractiveness elicited higher electroantennogram response amplitudes in two pairs, but in a third pair a higher electroantennogram response was found for the less attractive volunteer. These results confirm that odour contributes to the differences in attractiveness of humans to mosquitoes.     

Investigation of volatile biomarkers in lung cancer blood using solid-phase microextraction and capillary gas chromatography-mass spectrometry

In the present work, solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) was developed for investigation of lung cancer volatile biomarkers. Headspace SPME conditions (fiber coating, extraction temperature and extraction time) and desorption conditions were optimized and applied to determination of volatiles in human blood. To find the biomarkers of lung cancer, investigation of volatile compounds in lung cancer blood and control was performed by using the present method. Concentrations of hexanal and heptanal in lung cancer blood were found to be much higher than those in control blood. The two molecules of hexanal and heptanal were regarded as biomarkers of lung cancer. By comparison of volatiles in breath and in blood, it is demonstrated that hexanal and heptanal in breath were originated from blood and screening of lung cancer by breath analysis be feasible. These results show that SPME/GC-MS is a simple, rapid and sensitive method very suitable for investigation of volatile disease markers in human blood.     

固相微萃取技术在白蚁表皮碳氢化合物分析中的应用

利用固相微萃取(SPME)技术对白蚁表皮碳氢化合物进行萃取,选出较适合的萃取头,适宜的萃取温度和时间,同时利用GC-MS分析白蚁表皮碳氢化合物的组成成分及含量。结果表明,该白蚁表皮中含有24种碳氢化合物,主要为11,13-二甲基二十六烷烃(33.34%)和2,4,6,-三甲基二十七烷烃(15.75%)。     

Attraction of Lutzomyia longipalpis to human skin odours

Abstract. Male and female Lutzomyia longipalpis sandflies showed attraction to human skin emanations placed on warmed glass Petri dishes. Unfed virgin females were more strongly attracted than males, which also showed attraction. Four human subjects were tested and significant variation was found between the numbers of sandflies attracted to their skin emanations. This suggests that some individuals were more attractive than others. There was a significant difference between the response shown by sandflies from the Jacobina and Lapinha regions of Brazil, suggesting that sandflies from the Jacobina region were more anthropophilic. In addition, sandflies from Jacobina had a significantly higher level of activity than those from Lapinha. The role of sandfly attraction to humans as a risk factor in Leishmania transmission is considered.     

Characterisation of volatile organic compounds in stemwood using solid-phase microextraction

Solid-phase microextraction (SPME), hydrodistillation and dynamic headspace combined with GC and GC-MS were applied and compared for the analysis of volatile organic compounds (VOCs) from coniferous wood. The SPME conditions (type of fibre, size of wood sample, temperature and exposure time) were optimised, and more than 100 VOCs and semi-volatile compounds extracted and identified from the sapwood and heartwood of Norway spruce (Picea abies). The total number of mono- and sesquiterpenes eluted and identified was similar for the SPME and hydrodistillation methods, but more semi-volatile compounds were released by hydrodistillation. By applying dynamic headspace at room temperature, it was possible to analyse only the most volatile compounds. The qualitative composition of VOCs was similar in spruce sapwood and heartwood, although Z-beta-ocimene occurred only in sapwood while fenchol was present only in heartwood. SPME sampling coupled with GC, applied here to the analysis of VOCs released from stemwood of firs for the first time, is a convenient, sensitive, fast, solvent-free and simple method for the determination of wood volatiles. The technique requires much smaller sample amounts compared with hydrodistillation, and the total amount of VOCs extracted and identified is higher than that obtained by hydrodistillation or dynamic headspace. The relative ratios of the main mono- and sesquiterpenes and -terpenoids were similar using the SPME-GC and hydrodistillation methods.     

Quantitation of 2-chlorovinylarsonous acid in human urine by automated solid-phase microextraction--gas chromatography--mass spectrometry

Lewisite [dichloro(2-chlorovinyl)arsine] is a highly toxic chemical warfare agent with vesicant properties. The accidental exposure to lewisite or its intentional use as a chemical terrorism weapon are a public health threat and warrant investigations for the development of analytical methods to detect biomarkers of exposure to lewisite. Under aqueous conditions, lewisite rapidly hydrolyzes to the non-volatile 2-chlorovinylarsonous acid (CVAA). We have developed a sensitive, simple, and automated method for measuring CVAA in human urine. The assay is based on the use of solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) after derivatization of the CVAA with 1,3-propanedithiol (PDT). The volatile CVAA-PDT is adsorbed onto a SPME fiber and analyzed by GC-MS. The assay was validated on human urine samples spiked with CVAA to determine the accuracy, precision, and limit of detection (LOD). The LOD was 7.4 pg in 1 ml of urine.     

The study on the chromatographic fingerprint of Fructus xanthii by microwave assisted extraction coupled with GC-MS

The chromatographic fingerprint of Fructus xanthii, a kind of Traditional Chinese Medicines (TCMs), was studied by microwave assisted extraction (MAE) coupled with gas chromatography-mass spectrometry (GC-MS). The optimized conditions of MAE were examined. The method of MAE was evaluated in contrast to heat reflux extraction (HRE) method and by the validation tests of precision and repeatability. The relative standard deviations (RSDs) of retention time and peak area of each component were less than 0.2% and 6%, respectively. Twenty-five different batches of samples collected from different producing areas and the toasting process of F. xanthii were studied. The characteristic differences in the producing areas and the chemical variances in the toasting process were obtained and studied by principal components analysis (PCA) and similarity analysis. The trends of main varying components were attempted to be described in order to specify the related pharmacology and toxicology in crude and toasted samples. The results suggest that the chromatographic fingerprint developed by MAE coupled with GC-MS provides useful information to reveal the quality of F. xanthii and evaluate the quality changes in the producing process.     

The effect of lactic acid on odour-related host preference of yellow fever mosquitoes.

In a behavioural study we have investigated the role of lactic acid for the host preferences of yellow fever mosquitoes (Aedes aegypti) by comparing the attractiveness of rubbings from the hands of different human individuals and extracts obtained from skin rubbings from different mammals (Bos primigenius f. taurus, Capra aegagrus f. hircus, Felis silvestris f. catus and Homo sapiens). Certain human individuals were consistently more attractive to mosquitoes than others. Addition of lactic acid markedly increased the degree of attractiveness of formerly less attractive human odour samples and they were preferred over those which were originally the most attractive. There was almost no response to animal odour samples. In contrast to human samples, which contain a high amount of lactate, this compound could not be detected in samples from animals. When skin emanations from animals were combined with lactic acid, however, as many mosquitoes responded to odour samples of B. primigenius f. taurus and C. aegagrus f. hircus as did to human odours. All these data demonstrate that olfactory-based host preference of the anthropophilic mosquito A. aegypti is to a large extent due to differences in the amount of lactic acid in the odour samples.     

Application of solid-phase microextraction in the investigation of protein binding of pharmaceuticals

Protein-drug interactions of seven common pharmaceuticals were studied using solid-phase microextraction (SPME). SPME can be used in such investigations on the condition that no analyte depletion occurs. In multi-compartment systems (e.g. a proteinaceous matrix) only the free portion of the analyte is able to partition into the SPME fiber. In addition if no sample depletion occurs, the bound drug-free drug equilibria are not disturbed. In the present study seven pharmaceuticals (quinine, quinidine, naproxen, ciprofloxacin, haloperidol, paclitaxel and nortriptyline) were assayed by SPME. For quantitative purposes SPME was validated first in the absence of proteins. Calibration curves were constructed for each drug by HPLC-fluorescence and HPLC-UV analysis. SPME was combined to HPLC off-line, desorption occurring in HPLC inserts filled with 200 microL methanol. Binding of each drug to human serum albumin was studied independently. Experimental results were in agreement with literature data and ultrafiltration experiments, indicating the feasibility of the method for such bioanalytical purposes.     

太浦河大型底栖动物群落组成及时空分布特征

太浦河连接东太湖和黄浦江,是东太湖向下游行洪的主河道,也是黄浦江上游重要的引水水源。分别于2017年10月、12月和2018年3月、6月在太浦河沿程设置的5个站点开展了大型底栖动物季节频次的取样调研,分析了太浦河大型底栖动物群落的结构特征及其主要影响因子。调查期间共采集到大型底栖动物25种,隶属于3门6纲14科,其中以河蚬（Corbicula fluminea）为代表的双壳类和以铜锈环棱螺（Bellamya aeruginosa）为代表的腹足类处优势地位。太浦河大型底栖动物群落的密度、生物量及多样性特征在不同站点间均存在显著差异（P<0.05）;而在不同季节间均不存在显著差异（P>0.05）。聚类排序分析表明,太浦河大型底栖动物群落在空间上的差异较季节间的变化更为明显。太浦河大型底栖动物群落的物种组成特征与太浦河、东太湖的水文连通格局密切相关;而沿程不同程度人为干扰下的水体营养水平以及底质类型与生境异质性等生境条件对太浦河大型底栖动物群落的分布特征具有重要影响,其综合作用机理有待进一步研究。     

山鸡椒挥发油GC-MS指纹图谱及模式识别研究

为控制山鸡椒挥发油的质量,通过水蒸气蒸馏法分离出山鸡椒挥发油,利用GC-MS建立了山鸡椒挥发油的指纹图谱,并运用主成分分析和聚类分析对指纹图谱进行模式识别研究。结果显示16批样本图谱共匹配出27个共有峰,以此27个峰为评价指标,样本的相似度均大于0.98。对27个共有峰中的18个峰进行了定性,以此18个峰为评价指标,方法学考察结果较好,主成分分析和聚类分析结果基本一致。表明该方法建立的GC-MS指纹图谱具有良好的稳定性和可靠性。同时,模式识别显示不同产地间和同一产地内的山鸡椒挥发油都存在差异。     

Indole and 3-chloroindole: The source of the disagreeable odor of Hygrophorus paupertinus

The odor emanating from sporocarps of Hygrophorus paupertinus is disagreeable and fecal-like. Solid phase microextraction (SPME) and analysis by gas chromatography-mass spectrometry (GC-MS) showed 1-octen-3-ol, indole and 3-chloroindole were responsible for the odor. This is the first case in which 3-chloroindole has been identified from a terrestrial organism.