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PubMed2006

The frequency of occurrence and discriminatory power of compounds found in human scent across a population determined by SPME-GC/MS.

The composition of human scent collected from the hands is of interest to the medical community as a mechanism to diagnose disease and the forensic community as a means to investigate canine scent discriminations. An extensive survey of the volatile organic compounds (VOCs) identified in the headspace of hand odor samples utilizing solid phase micro-extraction gas chromatography/mass spectrometry (SPME-GC/MS) has been conducted to determine the constituents of the human base odor profile. Sixty-three compounds were extracted from the collected odor samples. The composition included acids, alcohols, aldehydes, hydrocarbons, esters, ketones and nitrogen-containing compounds. The majority of the compounds detected (79.4%) were present in less than one third of the individuals sampled. Spearman correlation coefficient comparisons at a match/no-match threshold of 0.9 produced a distinguish ability of 99.67% across the population.

Adolescent↗

PubMed2002

Epidemiologic evidence for asthma and exposure to air toxics: linkages between occupational, indoor, and community air pollution research.

Outdoor ambient air pollutant exposures in communities are relevant to the acute exacerbation and possibly the onset of asthma. However, the complexity of pollutant mixtures and etiologic heterogeneity of asthma has made it difficult to identify causal components in those mixtures. Occupational exposures associated with asthma may yield clues to causal components in ambient air pollution because such exposures are often identifiable as single-chemical agents (e.g., metal compounds). However, translating occupational to community exposure-response relationships is limited. Of the air toxics found to cause occupational asthma, only formaldehyde has been frequently investigated in epidemiologic studies of allergic respiratory responses to indoor air, where general consistency can be shown despite lower ambient exposures. The specific volatile organic compounds (VOCs) identified in association with occupational asthma are generally not the same as those in studies showing respiratory effects of VOC mixtures on nonoccupational adult and pediatric asthma. In addition, experimental evidence indicates that airborne polycyclic aromatic hydrocarbon (PAH) exposures linked to diesel exhaust particles (DEPs) have proinflammatory effects on airways, but there is insufficient supporting evidence from the occupational literature of effects of DEPs on asthma or lung function. In contrast, nonoccupational epidemiologic studies have frequently shown associations between allergic responses or asthma with exposures to ambient air pollutant mixtures with PAH components, including black smoke, high home or school traffic density (particularly truck traffic), and environmental tobacco smoke. Other particle-phase and gaseous co-pollutants are likely causal in these associations as well. Epidemiologic research on the relationship of both asthma onset and exacerbation to air pollution is needed to disentangle effects of air toxics from monitored criteria air pollutants such as particle mass. Community studies should focus on air toxics expected to have adverse respiratory effects based on biological mechanisms, particularly irritant and immunological pathways to asthma onset and exacerbation.

Air Pollutants↗

PubMed2026

Trichoderma specialized metabolites in biocontrol: gene-metabolite links, ecological functions, and translational bottlenecks.

Trichoderma spp. produce a diverse repertoire of metabolites with specific activities that contribute to biocontrol through direct antagonism, ecological signalling, and modulation of plant responses. However, current knowledge remains uneven: many metabolites are chemically described, whereas fewer are supported by robust gene-metabolite associations, experimentally validated ecological functions, and realistic translational evidence. Progress in this field will depend less on expanding compound catalogues than on integrating mechanistic, ecological, and translational evidence. This review examines the specialized metabolism of Trichoderma with emphasis on biosynthetic gene clusters, regulatory networks, ecological roles, and biosafety constraints relevant to biocontrol. Major metabolite classes, including polyketides, terpenoids, peptaibols, siderophores, diketopiperazines, and volatile organic compounds, are discussed together with representative case studies for which genetic and functional evidence is available. We further propose a translational framework to distinguish metabolites with mainly descriptive support from those approaching application readiness, based on four criteria: gene-level validation, demonstrated ecological role, manageable biosafety profile, and feasible delivery/stability. This perspective helps explain why metabolite inventories continue to expand faster than field translation. Recent advances in genomics, transcriptomics, metabolomics, genome editing, and formulation science are reshaping how Trichoderma metabolites are prioritized for future development.

Biosafety↗

PubMed2004

A novel method for rapidly diagnosing the causes of diarrhoea.

BACKGROUND: The microbiological diagnosis of infectious diarrhoea may take several days using conventional techniques. In order to determine whether flatus can be used to make a rapid diagnosis, the volatile organic compounds associated with diarrhoea were analysed. METHODS: Stool samples were collected from 35 patients with infectious diarrhoea and from six healthy controls. Gaseous compounds were extracted from a headspace using solid phase microextraction and analysed using gas chromatography and mass spectroscopy. RESULTS: Characteristic patterns of volatile gases were found for the main causes of infectious diarrhoea in hospitals. Furan species without indoles indicated Clostridium difficile, ethyl dodecanoate indicated rotavirus, ammonia without ethyl dodecanoate suggested other enteric viruses, and the absence of hydrocarbons and terpenes indicated Campylobacter infection. CONCLUSION: These results could be the basis of rapid near patient diagnosis of infectious diarrhoea.

Adolescent↗

PubMed2003

A new tool for laboratory studies on volatilization: extension of applicability of the photovolatility chamber.

Volatilization from soil and plant surfaces after application is an important source of pesticide residues to the atmosphere. The laboratory photovolatility chamber allows the simultaneous measurement of volatilization and photodegradation of 14C-labeled pesticides under controlled climatic conditions. Both continuous air sampling, which quantifies volatile organic compounds and 14CO2 separately, and the detection of surface-located residues allow for a mass balance of radioactivity. The setup of the photovolatility chamber was optimized, and additional sensors were installed to characterize the influence of soil moisture, soil temperature, and evaporation on volatilization. The modified flow profile in the glass dome of the chamber arising from the use of a high-performance metal bellows pump was measured. Diminished air velocity near the soil surface and a wind velocity of 0.2 m/s in 3 cm height allowed the requirements of the German guideline on assessing pesticide volatilization for registration purposes to be fulfilled. Determination of soil moisture profiles of the upper soil layer illustrated that defined water content in the soil up to a depth of 4 cm could be achieved by water saturation of air. Cumulative volatilization of [phenyl-UL-14C]parathion-methyl ranged from 2.4% under dry conditions to 32.9% under moist conditions and revealed the clear dependence of volatilization on the water content in the top layer.

Air↗

PubMed2001

The influence of sex, allergic rhinitis, and test system on nasal sensitivity to airborne irritants: a pilot study.

"Nasal irritant sensitivity" is an important construct in environmental health science; functional measures, however, lack standardization. We performed duplicate measures of nasal irritant perceptual acuity on 16 subjects (evenly divided by sex and seasonal allergy status) using two different test compounds: carbon dioxide (CO2) (detection) and n-propanol (localization). The a priori hypotheses included a) allergic rhinitics will display lower perceptual thresholds than nonrhinitics; b) females will display lower perceptual thresholds than males; and c) estimates of perceptual acuity using the two test systems will be positively correlated. We obtained CO2 detection thresholds using an ascending concentration series, presenting 3-sec pulses of CO2, paired with air in random order, by nasal cannula. We obtained localization thresholds by simultaneously presenting stimuli (ascending concentrations of n-propanol vapor in air) and blanks (saturated water vapor in air) to opposite nostrils, with laterality randomized. In terms of test-retest reliability, individual replicate measures for CO2 detection thresholds correlated more closely than did the localization thresholds of volatile organic compounds (VOC) (r = 0.65 and r = 0.60, respectively). As an intertest comparison, log-transformed individual mean CO2 and VOC measures were positively correlated with an r of 0.63 (p < 0.01). In univariate analyses, sex predicted both log-transformed CO2 and VOC thresholds (females being more "sensitive"; p < 0.05 and 0.001, respectively). Nasal allergies predicted sensory testing results only in the multivariate analysis, and then only for VOC localization (p < 0.05). The question of population variation in nasal irritant sensitivity (as well as the generalizability of results across test compounds) deserves further attention.

1-Propanol↗

PubMed2006

Chemical characterization of odorous gases at a landfill site by gas chromatography-mass spectrometry.

The composition of odorous gases emitted from a municipal landfill in the city of Izmir, Turkey was investigated using gas chromatography-mass spectrometry, and these data were examined in relation with the odor concentrations. Several volatile organic compounds (VOCs) were identified and quantified at five sampling sites in May and September 2005. Detected VOCs were monoaromatics (0.09-47.42 microg m(-3)), halogenated compounds (0.001-62.91microg m(-3)), aldehydes (0.01-38.55 microg m(-3)), esters (0.01-7.54 microg m(-3)), ketones (0.03-67.60 microg m(-3)), sulfur/nitrogen containing compounds (0.03-5.05 microg m(-3)), and volatile fatty acids (VFAs) (0.05-43.71 microg m(-3)). High levels of aldehydes (propanal up to 38.55 microg m(-3)) and VFAs (formic acid up to 43.71 microg m(-3)) were measured in May. However, VOC concentrations were relatively low in September. The monoaromatics and halogenated compounds were the abundant VOCs in landfill air for the both sampling periods. The benzene-to-toluene (B:T) ratio at the landfill site was significantly lower than urban areas indicating the presence of higher amounts of toluene in landfills compared to traffic exhaust rich urban areas. A statistically significant linear relationship was found between odor concentrations determined by olfactometry and total VOC concentrations. The relationships of odor concentrations with the different groups of chemicals were also examined using a step-wise multiple regression analysis. It was found that the concentrations of aldehydes, ketones, and esters are the best estimators, explaining 96% of the variability in odor concentrations (r2 = 0.96, n = 10, P < 0.01).

Air Pollutants↗

PubMed2001

Prenatal exposure to pesticides: a feasibility study among migrant and seasonal farmworkers.

BACKGROUND: Migrant and seasonal farmworkers have a high potential for pesticide exposures, yet are rarely included in epidemiologic studies. This study examined the feasibility of assessing prenatal exposures to pesticides and other compounds in pregnant Hispanic farmworkers. METHODS: Nine women completed a survey about work experiences during pregnancy. Maternal urine, cord blood, and placenta samples were obtained at delivery for analysis of 51 analytes, including 6 phenoxy acid or triazine herbicides, 21 organochlorine insecticides, 10 PCBs, and 14 volatile organic compounds. RESULTS: Seven of 51 analytes were found in the biological samples. DDE, DDT, dichlorbenzene, toluene, trimethylbenzene, and endosulfan sulfate were detected in cord blood samples, and 2,4-D in urine from one or more women. CONCLUSIONS: We documented the feasibility of following farmworkers to assess in utero exposure to pesticides and other contaminants, and demonstrated exposure to these compounds. Difficulties in measuring pesticides with short half lives were noted.

Adolescent↗

PubMed2004

A plasma membrane protein from Zea mays binds with the herbivore elicitor volicitin.

Volicitin (17-hydroxylinolenoyl-l-Gln) present in the regurgitant of Spodoptera exigua (beet armyworm caterpillars) activates the emission of volatile organic compounds (VOCs) when in contact with damaged Zea mays cv Delprim (maize) leaves. VOC emissions in turn serve as a signaling defense for the plant by attracting female parasitic wasps that prey on herbivore larvae. A tritiated form of volicitin was synthesized and shown to induce volatiles in the same fashion as the biological form. [(3)H]-l-volicitin rapidly, reversibly, and saturably bound to enriched plasma membrane fractions isolated from Z. mays leaves with an apparent K(d) of 1.3 nM and a Hill coefficient of 1.07. Analog studies showed that the l-Gln and hydroxy moieties of volicitin play an important role in binding. Treatment of plants with methyl jasmonate (MeJA) increased the total binding of [(3)H]-l-volicitin to the enriched plasma membrane more than threefold, suggesting that MeJA activates transcription of the gene encoding the binding protein. S. exigua feeding also increased total binding fourfold. Cycloheximide pretreatment of plants significantly decreased binding of radiolabeled volicitin to the enriched plasma membrane. These data provide the first experimental evidence that initiation of plant defenses in response to herbivore damage can be mediated by a binding protein-ligand interaction.

Acetates↗

PubMed2005

Origin of 2-ethylhexanol as a VOC.

2-Ethylhexanol has been identified as a volatile organic compound (VOC) that contributes to the deterioration of indoor air quality. Plasticizers are common components of dust and building materials and are shown to be degraded by a variety of bacteria and fungi to produce 2-ethylhexanol and other metabolites. Of these, the 2-ethylhexanol has significant volatility and was observed in appreciable quantities. The degree to which 2-ethylhexanol is observed as a VOC in air samples would be limited by the fact that many of the microorganisms that are capable of producing this compound are also able to oxidize it to 2-ethylhexanoic acid, which is much less volatile. It is argued that an abiotic degradation mechanism of plasticizers that results in the generation of 2-ethylhexanol is unlikely and, if this did occur, other metabolites should have been observed. Thus, the microbial degradation of plasticizers is the most likely source of 2-ethylhexanol in indoor air.

Air Microbiology↗

PubMed2004

Genotoxic and mutagenic activity of environmental air samples in Flanders, Belgium.

Atmospheric pollution is assumed to play a role in the incidence of respiratory diseases and cancers. Airborne particles are able to penetrate deep into the lung and are composed of complex chemical mixtures, including mutagens and carcinogens such as polycyclic aromatic compounds (PACs). The present study reports mutagenic and genotoxic activities associated with ambient air collected near a busy street in Borgerhout, at an industrial site in Hoboken and in Peer, a rural community 70 km east of Antwerp in Flanders, Belgium. Airborne particulates (PM10) and semi-volatile organic compounds were sampled during winter and summer. Samples were collected with a high-volume sampler using quartz filters (QF) and polyurethane foam (PUF) cartridges. The mutagenic and genotoxic activity of the organic extracts was determined using the Salmonella test/standard plate-incorporation assay and the Vitotox assay. Concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in the extracts were determined by reversed-phase high-performance liquid chromatography (HPLC). The mutagenicity assay, using Salmonella typhimurium strain TA98, demonstrated direct mutagenicity of up to 58 revertants/m3 for the QF extracts and low or no mutagenic activity in the PUF extracts. Metabolic activation of the samples resulted in high indirect mutagenicity for both QF and PUF extracts: up to 96 revertants/m3 were found in QF samples and 62 revertants/m3 in PUF samples. Genotoxic effects of the filter extracts were assessed with the Vitotox assay: some direct genotoxic effects were noted, i.e. without metabolic activation, but almost no effects were observed after metabolic activation. Without activation, most PUF extracts were bacteriotoxic. With metabolic activation this toxicity disappeared, but genotoxic effects were not observed. Statistical analysis showed that the observed biological effects correlated well with the PAH concentrations.

Air Pollutants↗

PubMed2006

Volatile signaling in plant-plant interactions: "talking trees" in the genomics era.

Plants may "eavesdrop" on volatile organic compounds (VOCs) released by herbivore-attacked neighbors to activate defenses before being attacked themselves. Transcriptome and signal cascade analyses of VOC-exposed plants suggest that plants eavesdrop to prime direct and indirect defenses and to hone competitive abilities. Advances in research on VOC biosynthesis and perception have facilitated the production of plants that are genetically "deaf" to particular VOCs or "mute" in elements of their volatile vocabulary. Such plants, together with advances in VOC analytical instrumentation, will allow researchers to determine whether fluency enhances the fitness of plants in natural communities.

Adaptation, Physiological↗

PubMed2003

Municipal waste incinerators: air and biological monitoring of workers for exposure to particles, metals, and organic compounds.

AIMS: To evaluate occupational exposure to toxic pollutants at municipal waste incinerators (MWIs). METHODS: Twenty nine male subjects working near the furnaces in two MWIs, and 17 subjects not occupationally exposed to combustion generated pollutants were studied. Individual air samples were taken throughout the shift; urine samples were collected before and after. Stationary air samples were taken near potential sources of emission. RESULTS: Occupational exposure did not result in the infringement of any occupational threshold limit value. Atmospheric exposure levels to particles and metals were 10-100 times higher in MWIs than at the control site. The main sources were cleaning operations for particles, and residue transfer and disposal operations for metals. MWI workers were not exposed to higher levels of polycyclic aromatic hydrocarbons than workers who are routinely in contact with vehicle exhaust. The air concentrations of volatile organic compounds and aldehydes were low and did not appear to pose any significant threat to human health. Only the measurement of chlorinated hydrocarbon levels would seem to be a reliable marker for the combustion of plastics. Urine metal levels were significantly higher at plant 1 than at plant 2 because of high levels of pollutants emanating from one old furnace. CONCLUSION: While biological monitoring is an easy way of acquiring data on long term personal exposure, air monitoring remains the only method that makes it possible to identify the primary sources of pollutant emission which need to be controlled if occupational exposure and environmental pollution are to be reduced.

Air Pollutants, Occupational↗

PubMed2003

Calibration system and analytical considerations for quantitative sesquiterpene measurements in air.

Sesquiterpenes (C15H24, SQT) are semi-volatile organic compounds emitted from vegetation and are of interest for air quality considerations because of their suspected contribution to the formation of secondary aerosol. This article investigates the application of a capillary diffusion method for the generation of standard atmospheres of 16 SQT and four other related semi-volatile compounds. This instrument subsequently has been used in the testing of analytical materials, protocols and calibration of air sampling methods. SQT DB-1 retention indices, vapor pressures at 25 and 75 degrees C, and diffusion coefficients were determined. A quantitative, on-line GC method yielded improved results (median relative standard deviation of 5.0-6.1%) for the diffusion rate determination in comparison to a gravimetric approach (median relative standard deviation 18%). The GC method also allowed identifying errors in the gravimetric method stemming from residual solvent evaporation, impurities, and chemical analyte losses. Stainless steel, glass, nickel and PTFE tubing that were tested for transfer lines and a sampling loop had to be kept at temperatures in excess of approximately 110 degrees C in order to prevent significant analytical errors from the stickiness of SQT to these materials. In addition to SQT analysis, results from this research provide general guidelines for gas-phase analysis of related compounds in the C14-C16 volatility range.

Air↗

PubMed1999

Characterization of compost biofiltration media.

The effect of compost quality on performance of biofiltration media was investigated. Three types of compost media were characterized in terms of their key properties, including pH, total organic carbon (TOC) and nitrogen, moisture content, oxygen uptake rates and heterotrophic and fungal plate counts. Laboratory-scale biofilter columns were each filled with a different compost medium mixed with buffer and a bulking agent. The columns were operated with a volatile organic compound (VOC) mixture consisting of ethyl alcohol, butyraldehyde, ethyl acetate, and 1,1-diethoxybutane and subjected to various operating conditions. After 13 months, the columns were sampled and post-characterization of the media was performed. A mixture of biosolids/horse manure compost, which had a high initial microbial activity, had the shortest acclimation period. Best overall performance, however, was observed with yard waste compost, which was the most stable medium. Media hydrophobicity was a key factor in long-term performance. Significant changes in compost structure, moisture content, pH, volatile solids, oxygen uptake rates, and microbial population densities were observed over the course of the study. Analyses of organic nitrogen content showed that significant amounts of nitrogen were not depleted from the media.

Air Pollution↗

PubMed2001

Indoor and outdoor BTX levels in German cities.

On the basis of the ongoing study INGA (INdoor exposure and Genetics in Asthma), Germany's most detailed and standardized epidemiological study on indoor exposure to both allergens in house dust and volatile compounds in the air of the home environment has been performed. The purpose of this paper is to describe the spatial and seasonal variability of indoor and outdoor BTX (Benzene, toluene, ethyl benzene, ortho-xylene, meta- and para-xylene) concentrations for the study period from June 1995 to November 1996. Within this framework, air concentrations of volatile organic compounds (BTX) were measured in 204 households in Erfurt (Eastern Germany) and 201 households in Hamburg (Western Germany). BTX sampling was conducted over one week using OVM 3500 passive diffusion sampling devices in the indoor (living room and bedroom) and outdoor environment (outside the window of the living room). Indoor and outdoor median BTX concentrations in Erfurt were slightly, but significantly higher than those in Hamburg. This gap was most pronounced in the levels of indoor toluene (37.3 microg/m3 for Erfurt and 20.5 microg/m3 for Hamburg, P < 0.0001). In both cities, winter indoor and outdoor concentrations for the five compounds exceeded the summer values. Outdoor concentrations of ethyl benzene and ortho-xylene were very low (50% < L.D.). In general, the indoor BTX air concentrations were significantly higher than the outdoor concentra- tions, the lowest I/O ratios were found in the case of benzene. Living room and bedroom values for the five compounds were highly correlated (Spearman coefficient 0.5-0.9). Despite the better insulation of the homes in West Germany, no indication for the expected higher indoor concentrations of BTX in the West could be found. The strong and yet undiscovered indoor source for toluene in East Germany might lead to a further increase in the indoor air load in those homes in the East, which undergo renovations which will lead to improved insulation.

Air Pollutants↗

PubMed2004

Breath analysis in critically ill patients: potential and limitations.

Breath tests are attractive since they are noninvasive and can be repeated frequently in the dynamically changing state of critically ill patients. Volatile organic compounds can be produced anywhere in the body and are transported via the bloodstream and exhaled through the lung. They can reflect physiologic or pathologic biochemical processes such as lipid peroxidation, liver disease, renal failure, allograft rejection, and dextrose or cholesterol metabolism. This review describes the diagnostic potential of endogenous organic volatile substances in the breath of critically ill patients. Since many of these patients require ventilatory support, aspects of breath analysis under mechanical ventilation will be addressed. Analytical procedures, problems concerning the physiologic meaning of breath markers and future developments will be discussed.

Biomarkers↗

PubMed2005

Bio-effect monitoring using a [(15)N]methacetin test as diagnostic tool to monitor remediation effects in an industrially polluted region.

The classical way to demonstrate the efficiency of remediation is measuring the reduction of toxic compounds in the environment. Nevertheless, more important is the risk reduction in human health. To determine changing health effects, exposure and bio-effects have to be monitored at time of and during remediation. Kindergarten children from a heavily polluted industrial (n=23) and a control area (n=12) were investigated. The region-specific outdoor and indoor exposure [27 volatile organic compounds (VOC), emphasis on tri- and tetrachloroethylene (TRI, TETRA)], the internal load [(trichloroacetic acid-TCA-as urine metabolites of TRI and TETRA and S-phenyl- and S-benzylmercapturic acid (SPMA and SBMA) as metabolites of benzene and toluene], and biological effect assessment ([(15)N]methacetin test-a non-invasive stable isotope test to determine the unspecific liver detoxification capacity of an individual) were measured twice a year during 2 years of remediation (1997/1998). It could be shown that in- and outdoor levels of TRI and TETRA decreased by 47% in the heavily polluted village, Greppin, while the levels remained much the same in the control village, Roitzsch. This trend was reflected in the decreasing elimination of TCA in the urine (41%) by the Greppin children, with no differences in the TCA elimination in Roitzsch probands. As the remediation efforts decreased the burden of exposure, the children's liver detoxification capacity improved as well. Combining different methods, such as exposure-effect (external and internal loads) and bio-effect monitoring, proved to be useful to assess remediation successes including the improvement in human health.

Acetamides↗