Volatile compounds metabolism

Flavor and aroma of fruit and scent of flowers is represented by a mixture of dozens of volatile components [160, 161]. Most of these volatiles are derived from three chemical groups, namely isoprenoids, phenylpropanoids and aliphatics. Several volatiles in the mixture will have a dominant effect on the overall fruit aroma or flower scent that is independent from their relative levels. Namely, trace levels of a certain component might have a substantial effect on the typical aroma and scent associated with a particular fruit or flower. Due to promiscuity of enzymes associated with volatile compounds metabolism, a relatively large number of volatile components could be altered by modifying a single gene. For instance, overexpression of the ( )-j3-caryophyllene synthase from rice in Arabidopsis results in emission of a bouquet of terpenoid volatiles, including (EyP-caryophyllene, j8-elemene and a-humulene... 

Antibiosis Inhibition or lysis of an organism mediated by metabolic products of the antagonist these products include lytic agents, enzymes, volatile compounds, and other toxic substances. 

Dermal absorption for compounds that are volatile and metabolized to carbon dioxide (June 1996) 870.8320 Oral/dermal pharmacokinetics (June 1996)... 

The origin of the volatile compounds that differ between the two barley cultivars is not known. Three sources for the differing compounds are possible. The first one is the original root exudate (6,7). In this case the results reflects cultivar variation in plant metabolism and thus the potential of the plant in controlling its environment. 

Some volatile compounds such as methanethiol, dimethylsulfide and dimethyldisulfide have been shown to yield methane when they were added to anaerobic cultures derived from aquatic sediments (70. 71V Kiene et al. (22) showed that methane bacteria and sulfate-reducers competed for dimethyldisulfide when it was added at low concentrations to anaerobic aquatic sediments. They also isolated a methanogen that metabolized dimethyldisulfide to methane and carbon dioxide (72). Recently Oremland et al (22) detected trace amounts of ethane released from anoxic sediment slurries. This could be stimulated by the addition of ethanethiol or diethylsulfide and inhibited by the addition of bromoethanesulfonic acid which specifically inhibits methane bacteria. These results indicated that methane bacteria co-metabolized these two OSC. 

The likelihood that a xenobiotic species will undergo enzymatic metabolism in the body depends on the chemical nature of the species. Compounds with a high degree of polarity, such as relatively ionizable carboxylic acids, are less likely to enter the body system and, when they do, tend to be quickly excreted. Therefore, such compounds are unavailable, or available for only a short time, for enzymatic metabolism. Volatile compounds, such as dichloromethane or diethylether, are... 

During the biological aging of sherry, the concentration of ethanol decreases because of its consumption by flor yeast. Its respiration via the tricarboxylic acid pathway (Suarez-Lepez and Inigo-Leal, 2004) provides the main source of carbon and energy. Acetaldehyde is the main organic byproduct of ethanol metabolism, but other volatile compounds, notably acetic acid, butanediol, diacetyl, and acetoin, can also be formed. In addition,... 

The kidney is an important organ for the excretion of toxic materials and their metabolites, and measurement of these substances in urine may provide a convenient basis for monitoring the exposure of an individual to the parent compound in his or her immediate environment. The liver has as one of its functions the metabolism of foreign compounds some pathways result in detoxification and others in metabolic activation. Also, the liver may serve as a route of elimination of toxic materials by excretion in bile. In addition to the liver (bile) and kidney (urine) as routes of excretion, the lung may act as a route of elimination for volatile compounds. The excretion of materials in sweat, hair, and nails is usually insignificant. 

Several strains of LAB isolated from wine were tested for their abilities to metabolize ferulic and p-coumaric acids. Cavin et al. (1993) showed that these acids were strongly decarboxylated by growing cultures of Lactobacillus brevis, Lactobacillus plantarum, and Pediococcus when decarboxylation was observed, volatile phenols (4-ethylguaiacol and 4-ethylphenol) were detected, indicating the possibility of reduction of the side chain before or after decarboxylation. Couto et al. (2006) reported L. collinoides as a producer of volatile phenols, although strain specificity concerning this capacity was observed. L. mali, L. sake, L. viridescens, and P. acidi-lactici were also found to be able to produce volatile compounds but they only perform the decarboxylation step. Volatile phenols cause animal taints such as horse sweat, wet animal and urine that are usually attributed to Brettanomyces spoilage. 

Picloram is not readily metabolized and is rapidly excreted unchanged in the urine and feces of treated rats, hollowing a 10 mg kg [ C]picloram intravenous dose, the isotope was cleared biophysical-ly and excreted in the urine. Balance studies in rats indicated that 98.4% of the dose was recovered. Urinary excretion resulted in an 80-84% recovery, fecal excretion resulted in 15% recovery less than 0.5% was recovered in the bile, and virtually no radioactivity was recovered as trapped " C02 or as other volatile compounds. Studies with [ " C]piclo-ram showed that 90% of the compound fed in the diet to dogs was excreted within 48 h in the urine, with small amounts appearing in the feces. 

Distribution, Storage and Excretion. Hydrocarbons in each of the aliphatic and aromatic fractions are expected to be distributed throughout tissues and organs following absorption. Preferential distribution to fatty tissues occurs especially with aliphatic hydrocarbons. Ingested or inhaled volatile aliphatic and aromatic hydrocarbons in the HC5-EC8 and EC5-EC9 fractions can be eliminated in exhaled breath as unchanged parent compound. Metabolic elimination of aromatic hydrocarbons in each EC fraction predominately occurs via oxidative metabolic pathways involving... 

The metabolic disorder diabetes causes a buildup of acetone (CH3COCH3) in the blood of untreated victims. Acetone, a volatile compound, is exhaled, giving the breath of untreated diabetics a distinctive odor. The acetone is produced by a breakdown of fats in a series of reactions. The equation for the last step is... 

B. cinerea metabolic studies. (Experiment 2). The volatile compounds formed by three different strains of B. cinerea (5901/2 5909/1 5899/4) (cf. Figure 1-2) were studied (strains obtained from Bayeri-sche Landesanstalt fUr Weinbau und Gartenbau, Wurzburg, culture collection). 

Gargas ML. 1990. An exhaled breath chamber system for assessing rates of metabolism and rates of gastrointestinal absorption with volatile compounds. 

According to several authors, cheese taste is mainly due to the compounds found in the cheese water-soluble extract (WSE) (1, 2). Thus, to study cheese taste, the focus is usually on the cheese WSE which contains small polar molecules such as minerals, acids, sugars, amino acids, peptides and some volatile compounds produced by different processes such as lipolysis, proteolysis microbial metabolism (3). These compounds are responsible for the individual taste sensations like sourness, bitterness and saltiness which are the main taste descriptors for cheese. However, in a complex mixture they also exert otiier taste sensations due to taste / taste interactions (4). Peptides are generally considered to be the main bitter stimuli in cheese (5). However, it was shown that in goat cheese, bitterness resulted mainly from die bitterness of calcium and magnesium chlorides, partially masked by sodium chloride (6). 

Clinical chemists and toxicologists should be aware that the detection of volatile substances in blood does not always indicate inhalant abuse or occupational exposure. Acetone and other volatile compounds may be found in ketoacidotic patients and some inborn errors of metabolism result in the accumulation of volatile compounds. Even though many studies and case reports have included concentrations of volatile substances in blood, definitive correlations between these blood concentrations and the clinical features of toxicity have not been demonstrated for any of these compounds. 

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