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In this study, physicochemical composition, nitrogen fractions and volatile compounds of goat cheeses manufactured using artisanal liquid coagulant by four different manufacturers in a mountainous area were investigated. Fresh goat cheeses were characterized by their high fat and high levels of total free amino acids. Volatile profiles were isolated by a solid-phase microextraction technique (SPME/GC–MS) and analyzed by gas chromography–mass spectrometry (GC–MS). In the cheeses, 50 aroma components were identified as ten acids, nine terpens, nine alcohols, eight esters, six aldehydes, five ketones, two volatile phenols and one norisoprenoid with 13 carbon atoms. The major aroma compounds found were nonanoic acid, 2-hexanol and acetoin.

In the last decade, research on deep eutectic solvents used in many fields with different roles in chemistry has attracted great interest. Literature reviewing shows that one of these solvents’ most common usage areas is extraction applications as green extraction media, especially to recover biomass conversion products. In this work, hydrophobic deep eutectic solvents (HDES) with different hydrogen bond donors (HBD) and hydrogen bond acceptor (HBA) were mixed and used as a solvent to separate butyric acid from aqueous solutions. Menthol (M)-based HDESs were prepared using three long-chain carboxylic acids (nonanoic acid (NA), decanoic acid (DA), and dodecanoic acid (DDA)) and trioctylphosphine oxide (TOPO) in different molar ratios of binary combinations. Density and refractive index values of HDES were determined. To assess the obtained results, extraction efficiency (E%) and distribution coefficient (D) values were calculated. It was observed that HDES containing menthol and TOPO were extracted more than 90% of butyric acid from the water phase. The transition of butyric acid from the aqueous to the organic phase was demonstrated by FTIR analysis. The Box-Behnken method based on response surface methodology (RSM) was used to explore the impacts of the experimental conditions on reactive extraction yield and to obtain a model equation for the separation of butyric acid from its aqueous solution using M:TOPO hydrophobic deep eutectic solvent.

Endogenous substances have been analyzed in biological samples in order to be related with metabolic dysfunctions and diseases. The study aimed to investigate profiles of volatile organic compounds (VOCs) from fresh and incubated saliva donated by healthy controls, individuals with oral tissue lesions and with oral cancer, in order to assess case-specific biomarkers of oxidative stress. VOCs were pre-concentrated using headspace-solid phase microextraction and analyzed using gas chromatography-mass spectrometry. Then, VOCs positively modulated by incubation process were subtracted, yielding profiles with selected features. Principal component analysis and hierarchical cluster analysis were used to inspect data distribution, while univariate statistics was applied to indicate potential markers of oral cancer. Machine learning algorithm was implemented, aiming multiclass prediction. The removal of bacterial contribution to VOC profiles allowed the obtaining of more specific case-related patterns. Artificial neural network model included 9 most relevant compounds (1-octen-3-ol, hexanoic acid, E-2-octenal, heptanoic acid, octanoic acid, E-2-nonenal, nonanoic acid, 2,4-decadienal and 9-undecenoic acid). Model performance was assessed using 10-fold cross validation and receiver operating characteristic curves. Obtained overall accuracy was 90%. Oral cancer cases were predicted with 100% of sensitivity and specificity. The selected VOCs were ascribed to lipid oxidation mechanism and presented potential to differentiate oral cancer from other inflammatory conditions. These results highlight the importance of interpretation of saliva composition and the clinical value of salivary VOCs. Elucidated metabolic alterations have the potential to aid the early detection of oral cancer and the monitoring of oral lesions.

The deterioration of soybean oil (SO), palm oil (PO), and rapeseed oil (RO) for deep-fat frying chicken breast meat (CBM) and potato chips (PCs) was evaluated based upon their short-chain fatty acids (SCFAs) profiles as well as free fatty acid (FFA) content, carbonyl value (CV), and total polar compounds (TPC) content. In addition, Fourier-transform infrared (FTIR) spectra of oils combined with partial least squares were applied to predict the FFA content, CV, and TPC content in oils. Results showed that the formation of SCFAs was accompanied the reduction of unsaturated fatty acids during 12 h/day for 3 days. For frying PCs with SO, the heptanoic acid (C7:0) continuously increased from 0.01 to 0.15 g/kg and octanoic acid (C8:0) increased from 0.008 to 0.65 g/kg, while the contents of linoleic and linolenic acids reduced from 45.69–41.43 to 4.03–3.20%, respectively. For frying CBM with RO, the contents of C7:0, C8:0, and nonanoic acid were in ranges of 0.05–0.38, 0.03–1.19, and 0.11–0.17 g/kg, while contents of linoleic and linolenic acids reduced from 22.15–18.89 to 7.83–6.21%, respectively. The FFA content, CV, and TPC content in oils predicted by the constructed linear regression model were in ranges of 0.21–2.61 KOH g/kg, 9.76–58.98 meq/kg, and 8.02–36.91%, respectively. The root mean standard error of prediction, coefficient of determination (R2) for the validation set, and ratio of prediction to deviation for all validation analyses were in ranges of 0.2127–6.7364, 0.8717–0.9608, and 1.1548–4.2984, respectively. A logistically positive relationship (R2 = 0.7982-0.9700) between the content of C8:0 and CV or TPC content was found in frying oils used for frying both CBM and PCs. Thus, both the measurement of SCFAs and FTIR analysis could be used to efficiently monitor the deterioration of frying oils during deep-fat frying.

The present study investigated the lipid oxidation degree of soybean oil during regularly discontinuous 40 h-deep-frying process. Electron spin resonance (ESR) spectroscopy technique was applied to identify and quantify the formed radicals, along with evaluation of physicochemical parameters including acid value (AV), peroxide value (PV), p-anisidine value (p-AnV), polar compounds (PC), fatty acid composition and volatile profile. Results showed the AV, p-AnV, PC and free radical of frying oil samples increased significantly with the increasing frying time. The results of fatty acids showed that unsaturated fatty acid such as C18:1 and C18:2 decreased by 19.98% and 14.58%, respectively, with prolonged frying time, while the content of C16:1, trans C18:1 and C18:2 increased by 20.38%, 425% and 42.86%, respectively, when compared to the fresh oil samples. In contrast, the content of saturated fatty acid had little change. In total, 37 volatile compounds were detected revealing a complex aroma profile of frying soybean oil, composed of 15 aldehydes, 8 alcohols, 4 ketones, 4 acids, 5 alkanes and 1 furan. Principal component analysis and hierarchical clustering analysis indicated that hexanal, heptanal, (E)-2-hexenal, octanal, (E)-2-heptenal, nonanal, (E)-2-octenal, undecanal, (E,E)-2,4-heptadienal, (E)-2-decenal, 2-undecenal, (E,E)-2,4-decadienal, 1-pentanol, 2,2-dimethyl-3-hexanol, (Z)-2-dodecenol, 1-octen-3-ol, pentanoic acid, octanoic acid, nonanoic acid and 2-pentyl-furan may be potential markers for evaluating lipid oxidation of frying soybean oil.

Bed bugs are pests of public health importance due to their relentless biting habits that can lead to allergies, secondary infections and mental health issues. When not feeding on human blood bed bugs aggregate in refuges close to human hosts. This aggregation behaviour could be exploited to lure bed bugs into traps for surveillance, treatment efficacy monitoring and mass trapping efforts, if the responsible cues are identified. The aim of this study was to identify and quantify the bed bug aggregation pheromone. Volatile chemicals were collected from bed bug-exposed papers, which are known to induce aggregation behaviour, by air entrainment. This extract was tested for behavioural and electrophysiological activity using a still-air olfactometer and electroantennography, respectively. Coupled gas chromatography-electroantennography (GC-EAG) was used to screen the extract and the GC-EAG-active chemicals, benzaldehyde, hexanal, (E)-2-octenal, octanal, nonanal, decanal, heptanal, (R,S)-1-octen-3-ol, 3-carene, β-phellandrene, (3E,5E)-octadien-2-one, (E)-2-nonenal, 2-decanone, dodecane, nonanoic acid, 2-(2-butoxyethoxy)ethyl acetate, (E)-2-undecanal and (S)-germacrene D, were identified by GC-mass spectrometry and quantified by GC. Synthetic blends, comprising 6, 16, and 18 compounds, at natural ratios, were then tested in the still-air olfactometer to determine behavioural activity. These aggregation chemicals can be manufactured into a lure that could be used to improve bed bug management.

The molecular structure of poly(3-hydroxyalkanoate) (P3HA) with medium-chain length, biosynthesized from Psuedomonas putida (P. putida), was investigated by thermal analysis, X-ray diffraction, and infrared spectrum. Cultivation in a medium of nonanoic acid and a mixed substrate of nonanoic acid and glycerin as carbon sources provided P3HA with monomer units of 7 and 9 carbons (P3HAn) and 5, 6, 7, 8, 9, and 10 carbons (P3HAmix). Since these P3HA has comparatively long side chains, the crystallinity was as low as about 10%. It was suggested that the hydrogen bonding plays an important role in constructing the crystal. The lamellar thickness was 1.20 nm, estimated from the melting temperature depression. This lamellar thickness corresponds to two repeating units. Crystallinity depending on time was observed by the CO stretching mode in the infrared spectrum, and then Avrami’s theory was applied to analyze the crystallization mechanism. The crystallization rate of P3HAn was very low, on the order of a few hours. An Avrami exponent of 1.45 was estimated from the slope of the Avrami plot. This shows that the conformational arrangement is presumably promoted along the chain axis. The slow crystallization is attributed to the long side chain, which prevents aggregation of the polymer chains.

Many Eryngium species have been traditionally used as ornamental, edible or medicinal plants. The gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC–MS) analyses have shown that the major compounds in the aerial parts were spathulenol (in E. campestre and E. palmatum oils) and germacrene D (in E. amethystinum oil). The main compounds in the root oil were nonanoic acid, 2,3,4-trimethylbenzaldehyde and octanoic acid for E. campestre, E. amethystinum and E. palmatum, respectively. All the oils expressed the highest potential against Gram-positive bacteria Staphylococcus aureus as well as Gram-negative Klebsiella pneumoniae and Proteus mirabilis. Molecular docking analysis was used for determining a potential antibacterial activity mechanism of compounds present in the essential oils. Molecular docking confirmed that the binding affinity of spathulenol to the active site of tyrosyl-tRNA synthetase was the highest among the tested dominant compounds. Regarding the total phenolic content (determined by the Folin–Ciocalteu assay) and flavonoid content (evaluated using aluminum nitrate nonahydrate), the highest amount was found in the ethyl acetate extract of E. palmatum. The results of DPPH and ABTS assay indicated that the highest antioxidant activity was present in the water extract of E. amethystinum. Extracts of the aerial parts presented as minimum inhibitory concentration (MIC) expressed the activity in the range 0.004–20.00 mg/mL, with the highest activity exhibited by the acetone and ethyl acetate extracts against Proteus mirabilis. The obtained results suggest that Eryngium species may be considered a beneficial native source of the compounds with antioxidant and antimicrobial properties.

In this study, the production of 9-(nonanoyloxy) nonanoic acid from oleic acid was investigated. The whole cell biotransformation of oleic acid includes OhyA (hydratase), ADH (alcohol dehydrdogenase), and BVMO (Baeyer-Villiger Monooxygenase) enzymes consecutively. BVMOs are known to catalyze oxidative cleavage of long chain aliphatic ketones (e.g., 2-decanone, 10-ketooctadecanoic acid). However, the enzymes are difficult to overexpress in a soluble form in microorganisms. Thereby, this study has focused on screening and functional expression of the BVMOs in Escherichia coli. Initially BVMOs were selected by protein sequence analysis and were examined for their ability to express in soluble and active form to generate 9-(nonanoyloxy)nonanoic acid from oleic acid. Secondly various optimization strategies of inducer concentrations, co-expression with molecular chaperones, and different media conditions were investigated. Among the 9 BVMOs screened, three BVMOs were found to produce the target product and among these, Di_BVMO3 isolated from Dietzia sp. D5 was found to be best. Further, the soluble expression of Di_BVMO3 was enhanced by adding phosphoglycerate kinase as N-terminal fusion tag. The whole cell biotransformation with fusion enzyme resulted in 3 ~ 5-fold enhancement in product formation compared with the non-fusion counterpart. Final productivity up to 105.3 mg/L was achieved. Besides Di-BVMO3, other two new BVMOs of Rh_BVMO4 from Rhodococcus sp. RHA1 and AFL838 from Aspergillus flavus NRRL3357 were screened for production of 9-(nonanoyloxy)nonanoic acid and could be used for whole cell biotransformation reaction of other long chain ketones.

Triptolide is the main active component of Tripterygium wilfordii Hook. F., which is one of the forbidden species by the Chinese Ministry of Health. A GC–MS-based metabolomic approach was applied to estimate the adipose toxicity induced by triptolide. The metabolomic study discovered that triptolide exposure caused a remarkable increase in fatty acids. For instance, nonanoic acid, dodecanoic acid, cis-9-hexadecenoic acid, hexadecanoic acid, 9,12-octadecadienoic acid, trans-9-octadecenoic acid, octadecanoic acid, arachidonic acid, and eicosanoic acid increased from 1.03- to 10.21-fold in high-dose triptolide-exposed rats compared to the control group. In addition, l-alanine, glycine, l-valine, fumaric acid, l-proline, glucose, and l-tyrosine were observed to have a down-regulation in the adipose tissue, induced by triptolide exposure. Many metabolites in high-dose group demonstrated the noticeable alterations in adipose tissue of rats brought by triptolide exposure, although the difference between low-dose group and control group was not noted. The results illustrated not only fatty acid β-oxidation, lipid accumulation, and reduction of amino acids in the adipose tissue of SD rats because of triptolide exposure, but also that the tricarboxylic acid cycle was influenced. A metabolomic method was successful in finding latent biomarkers.

Aqueous nanoparticle dispersions have been widely studied for their important industrial applications, including photocatalyst, coating, and casting. However, much less work has been conducted on nanoparticle dispersions in organic solvents, especially when co-dispersing with dissolved polymers. In this study, we explore TiO2/ZnO nanoparticle and poly(methyl methacrylate) (PMMA) co-dispersion in organic solvent anisole. To achieve uniformly dispersed suspensions, nanoparticle surface functionalization with nonanoic acid and 1-pentanol is conducted. Nonanoic acid has higher surface coverage on TiO2 and the two dispersants show similar surface coverage on ZnO. Heat treatment enhances the dispersant adsorption on the nanoparticle surfaces. For both TiO2/PMMA and ZnO/PMMA co-dispersions, higher solids loading leads to higher suspension viscosity. Higher volume fraction of nanoparticles in the nanoparticle plus PMMA solid phase results in lower viscosity, mainly by reducing the entanglement of the dissolved PMMA chains.

The biosynthesis of poly(3-hydroxyalkanoate) (PHA) by Pseudomonas putida (JCM6160) cultivated in a medium containing glycerol, nonanoic acid, or a glycerol/nonanoic acid mixture as the sole carbon sources was investigated. The PHA content was ~20 % when glycerol was the carbon source. This relatively low content can be attributed to the glycerol end-cap effect and the absence of enzymes that can directly synthesize PHA from acetyl CoA, which is the major metabolite of glycerol. Fatty acids, containing even numbered carbons, are synthesized from acetyl CoA, and they can be used as substrates for PHA synthesis. However, this process also results in decreasing PHA content as fatty acids are siphoned off into other pathways. However, addition of 5 mM nonanoic acid into a 20 mM glycerol-containing medium dramatically increased the PHA content in P. putida, which was 1.3 times larger than the sum of the values found when glycerol and nonanoic acid were each used as the sole carbon source. The PHA, synthesized in the glycerol/nonanoic acid medium, contains 3-hydroxy alkanoate units that have 5, 6, 7, 8, 9, or 10 carbons. The units that contain the even numbered carbons are derived from fatty acids that were produced from glycerol; whereas, the PHA units with the odd numbered carbons are derived from nonanoic acid. Pentanoate units were also found in the polyester derived from glycerol and nonanoic acid, and must have been synthesized indirectly via β-oxidation of nonanoic acid with the assistance of glycerol because pentanoate units were not found in PHA when P. putida was cultivated in the presence of only nonanoic acid.

Cleome viscosa L. (Capparidaceae) is well known for its medicinal properties. Lactam nonanoic acid (LNA) [2-amino-9-(4-oxoazetidin-2-yl)-nonanoic acid; C12H22N2O3, mol. wt. 242] has been isolated and purified from the root exudates of Cleome viscosa. The aqueous solution of this pure compound has been tested on bacteria (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) and fungi (Aspergillus fumigatus, A. niger and A. tamarii). At a dosage of 500 ppm and above, P. aeruginosa and S. aureus were totally inhibited while E. coli remained unaffected. On the other hand, growth of A. niger and A. tamarii was stimulated while there was no effect on A. fumigatus. This pure compound showed concentration-dependent inhibitory activity on rice, gram and mustard seeds.

Ghrelin, a novel peptide modified by n-octanoic acid at the third serine residue (Ser(3)), serves as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R) 1a. The octanoyl modification at Ser(3) is essential for receptor binding or growth hormone release. Here, we report the purification of caprine ghrelin and its physiological role in goats. The major form of caprine ghrelin is a 27 amino acid peptide that is octanoylated (C8:0) at Ser(3) and lacks Gln(14), which is present in rat and human ghrelin. Additionally, we identified various acyl modifications in caprine ghrelin: nonanoic (C9:0), decanoic (10:0), unsaturated octanoic acids (C8:1), and an unidentified fatty acid modification. We observed that differences in acyl modifications affected GHS-R1a activation. In addition, administration of synthetic bovine ghrelin increased plasma growth hormone (GH) levels in goats. Thus, the present study indicates a structural divergence in caprine ghrelin and suggests that ghrelin is involved in GH release in ruminants.

Capsiate has a structure similar to capsaicin but no oral pungency. Furthermore, capsiate displayed antioxidant activity and inhibited angiogenesis and vascular permeability, and therefore, showed potential as a medicine and food supplement. Capsaicin is now commercially available, however capsiate is scarcely present in natural foods. We investigated the direct enzymatic conversion of a capsaicinoid to a capsinoid. It was observed that the rate of lipase-catalyzed acylation of vanillyl alcohol with nonanoic acid was faster than that of hydrolysis of N-vanillylnonanamide to vanillyl amide and nonanoic acid in n-hexane at 70°C. As a result, we performed a one-procedure synthesis of capsiate from capsaicin via lipase-catalyzed transacylation.

Pseudomonas putida KT2440 grew on glucose at a specific rate of 0.48 h(-1) but accumulated almost no poly-3-hydroxyalkanoates (PHA). Subsequent nitrogen limitation on nonanoic acid resulted in the accumulation of only 27% medium-chain-length PHA (MCL-PHA). In contrast, exponential nonanoic acid-limited growth (mu = 0.15 h(-1)) produced 70 g l(-1) biomass containing 75% PHA. At a higher exponential feed rate (mu = 0.25 h(-1)), the overall productivity was increased but less biomass (56 g l(-1)) was produced due to higher oxygen demand, and the biomass contained less PHA (67%). It was concluded that carbon-limited exponential feeding of nonanoic acid or related substrates to cultures of P. putida KT2440 is a simple and highly effective method of producing MCL-PHA. Nitrogen limitation is unnecessary.

This study was carried out to identify unknown allelochemicals released from Myriophyllum spicatum and to investigate their anti-cyanobacterial effects. A series of analyses of culture solutions and methanol extracts of M. spicatum using gas chromatograph equipped with a mass selective detector revealed that M. spicatum released fatty acids, specifically, nonanoic, tetradecanoic, hexadecanoic, octadecanoic, and octadecenoic acids. Nonanoic, cis-6-octadecenoic, and cis-9-octadecenoic acids significantly inhibited growth of Microcystis aeruginosa, whereas tetradecanoic, hexadecanoic, and octadecanoic acids did not show any effect. When the inhibitory effect of nonanoic acid was compared with those of 4 polyphenols and eugeniin, which are anti-cyanobacterial compounds previously reported to be released by M. spicatum, nonanoic acid was found to be the most inhibitory to M. aeruginosa. These results indicate that not only polyphenols and eugeniin but also fatty acids such as nonanoic acid must be studied to reveal how M. spicatum exerts its allelopathic effect on M. aeruginosa.

Linden (Tilia cordata) bark was shown to contain an antifeedant effective against the large pine weevil, Hylobius abietis. Soxhlet extraction of inner and outer bark resulted in an extract that showed antifeedant activity in a microfeeding assay. The extract was fractionated by chromatography on silica gel using gradient elution with solvents of increasing polarity. The content of the fractions obtained was monitored by thin layer- and gas chromatography. Fractions of similar chemical composition were merged. Two of the 17 fractions showed antifeedant activity in the microfeeding assay. Nonanoic acid was identified in both of these fractions. Subsequent testing in the microfeeding assay showed that nonanoic acid possessed strong antifeedant activity against H. abietis adults.

Medium-chain-length fatty acids, such as nonanoic (9:0) and octanoic (8:0) acids, are more toxic to Ralstonia eutropha than volatile fatty acids such as acetic, propionic and butyric acids. Nonanoic acid was degraded to acetic and propionic acids via β-oxidation by Ralstonia eutropha for cell growth and synthesis of polyhydroxyalkanoates (PHAs). In a mixture of the fatty acids, utilization of nonanoic acid was depressed by acetic and propionic acids, and vice versa. The PHA accumulation from the volatile fatty acids was decreased from 53% (w/w) of dry cell mass to 23% due to the nonanoic acid. Similar phenomena were also observed with octanoic acid and its metabolic intermediates, acetic and butyric acids.

A gas chromatographic method for the analysis of seventeen acids in a water/ethanol matrix is described. The diluted samples were first concentrated by solid phase extraction. Nonanoic acid was the internal standard. A good separation profile was obtained for all compounds, including the isomers: n and iso-butyric acids, n and isovaleric acids and n and iso-caproic acids. The method is fast, sensitive (20–30 μg L−1) and has a good reproducibility (4–7 %). The recovery was in the range of 94%–116% for the medium chain acids (C7-C16). This method allowed the identification of fourteen acids in caninhas and other spirits. The total acid content and the profile of the exportation type caninhas are similar to the ones obtained for several international beverages.

Pseudomonas oleovorans was grown on nonanoic acid and 10-undecenoic acid, which were fed in sequence. The poly(3-hydroxyalkanoate)s (PHAs) which were isolated from cells harvested at different growth times, were characterized by solvent fractionation, crosslinking ability, gel permeation chromatography, 1H NMR spectroscopy, and differential scanning calorimetry. Two glass transitions were observed for the PHAs produced, and these corresponded to those of the PHAs produced from nonanoic acid [PHA(NA)] and 10-undecenoic acid [PHA(UA)] alone. The amounts of PHAs with repeating units produced from nonanoic acid remained constant while Pseudomonas oleovorans utilized UA for growth and PHA production. The molecular weight distributions of the PHAs obtained at different growth times were also constant. A crosslinking study showed that these polymers were mainly physical mixtures of PHA(NA) and PHA(UA). However, a fractionation study indicated that small amounts of the PHAS contained repeating units from both substrates, PHA(NA/UA).

Hexanal, octanal, nonanal, decanal, hexanoic acid, octanoic acid, nonanoic acid, and decanoic acid were identified in the volatile emissions from fifth instars ofSchistocerca gregaria by coupled gas chromatography-electroantennography (GC-EAD) detection and coupled GC-mass spectrometry (MS). In laboratory assays, synthetic blends of the eight compounds, with acids and aldehydes tested separately, evoked strong aggregation responses from fifth instars, similar to responses evoked by a crude volatile extract of the nymphs. A nymphal fecal volatile phenolic blend of guaiacol and phenol, which we have previously shown to evoke an aggregative response from different stages of the insect, significantly synergized the activity of the blend of eight compounds, suggesting mutually augmentative roles for nymphal and fecal volatiles in evoking aggregation. These results indicate that the aggregation behavior of gregarious second to fifth instars is modulated by three sets of pheromonal compounds: aldehydes and acids emitted by the nymphs themselves and phenols associated with their feces.

Bacillus thuringiensis is known as a bacterial species capable of the production of short side chain poly-β-hydroxyalkanoates (PHAs). In the present work it was shown that the organism is also capable of producing longer side chain PHAs under appropriate conditions. The microorganism was grown separately on glucose, nonanoic acid, and a mixture of glucose, peptone and casein in attempts to obtain poly-β-hydroxyalkanoates with varying lengths of the pendent alkyl group in the β-position of the polymer repeat unit. The growth on glucose resulted in the formation of poly-3-hydroxybutyrate, (PHB), which is a very common bacterial storage polymer, while the utilization of nonanoic acid resulted in the formation of a copolymer consisting of 3-hydroxynonanoate and 3-hydroxyheptanoate units (PHN/PHH), which is the usual product of the microbial utilization of this particular carbon source by Pseudomonas oleovorans.

Valproic acid (2-propylpentanoic acid) is an effective anticonvulsant widely used alone or in combination with other drugs (e.g., with carbamazepine, phenitoin, and phenobarbital) [1]. In the latter case, valproic acid (VA) decreases binding of other drugs (e.g., phenitoin and phenobarbital) to blood plasma proteins. On the other hand, phenitoin and phenobarbital also reduce the VA concentration in the blood plasma. VA is characterized by a high rate of absorption and elimination; for this reason the drug level in the plasma exhibits significant variations, especially if the interval between doses exceeds 8 h [2]. Therefore, monitoring of the VA level in the blood is very important both for successful therapy and for studying the VA pharmacokinetics and interactions with other drugs. Although numerous data have been reported on the determination of VA by various conventional methods [3 – 9], development of the new analytical procedures is still important for several reasons. First, VA, being a volatile compound, introduces large uncertainties as a result of losses in the sample concentration stage upon liquid extraction. Second, VA determination by HPLC with conventional UV detectors encounters problems related to weak optical absorption in this spectral range. For this reason, gas chromatography with a plasma-ionization detector was frequently preferred. However, being an acid, VA yields peaks with considerable tails on the GC chromatograms. This is usually eliminated by converting VA into derivatives (mostly by methylation) [3]. It should be noted that HPLC is still the most natural method for the analysis of biological samples, but VA has to be converted into derivatives exhibiting stronger absorption in the UV range, such as bromophenacyl, pentafluorobenzyl, or coumarin esters [4 – 9]. However, the release of VA in the course of derivatization (typically conducted in a micellar medium or upon precipitating proteins with acetonitrile [6, 9]) is incomplete because VA is strongly bound to proteins (80 – 90%) and is partly lost as a result of coprecipitation [6, 9]. Therefore, the total (bound plus free) VA concentration in the plasma is more reliably determined by methods involving the primary denaturation of proteins, followed by VA extraction with an appropriate organic solvent and, finally, derivatization [8]. The purpose of this study was to establish optimum conditions for VA extraction from blood plasma and conversion into bromophenacyl ester. We have also selected the optimum mobile and immobile phases for the HPLC analysis of bromophenacyl esters of VA (VABE) and nonanoic acid (NABE) and verified the method by determining VA in the blood plasma of experimental animals.

Ten known or potential components of the aggregation-attachment pheromone (AAP) of the ticks Amblyomma hebraeum and A. variegatum, as well as mixtures of these components, extracts of prefed males and live prefed males, were tested as aggregation stimulants. In field assays, laboratory-reared unfed male and female ticks were released 20 cm downwind of CO2/pheromone release sites; the numbers of ticks that aggregated at the release sites were recorded after 30 min. In A. variegatum, aggregation was induced by methyl salicylate, o-nitrophenol, 2,6-dichlorophenol, phenylacetaldehyde and some mixtures containing these compounds; a strong aggregation response was induced by an extract of five prefed males A. variegatum and a weak response was induced by an extract of 50 prefed males of A. hebraeum. In A. hebraeum, aggregation was induced by phenylacetaldehyde, mixtures of compounds that included phenylacetaldehyde, extracts of 50 prefed males of A. hebraeum or A. variegatum and 50 live prefed males of A. hebraeum. In A. variegatum, aggregation was inhibited if compounds that do not occur naturally in the AAP of the species were included in mixtures. In A. hebraeum, phenylacetaldehyde appeared to act as an arrestant for ticks that had been attracted to release sites by other compounds.

Three low molecular weight compounds were found in hexane:diethyl ether extracts of fed males of the African ticks, Amblyomma variegatum (tropical bont tick) and A. hebraeum (bont tick), namely, o-nitrophenol, methyl salicylate and 2,6-dichlorophenol. These same compounds were also fond in a rinse of fed A. variegatum males, but were absent or present in only trace amounts in a rinse of fed A. hebraeum males, o-Nitrophenol and methyl salicylate were present in much higher concentrations (i.e., amounts/tick) in A. variegatum than in A. hebraeum. 2,6-Dichlorophenol was also more abundant in A. variegatum than in A. hebraeum, but the differences were not as great as with the former two compounds. Extraction in hexane over a 3-week period revealed four additional compounds, benzaldehyde, benzyl alcohol, benzothiazole and nonanoic acid. The first three compounds were found in males of both species; nonanoic acid was found only in A. hebraeum males. Published reports consistently show strong attraction by o-nitrophenol and methyl salicylate for both sexes of the two bont tick species; 2,6-dichlorophenol and benzaldehyde have been reported to be attractive to both sexes of A. hebraeum. The possible roles of these compounds, as well as others occasionally reported from A. hebraeum and A. variegatum, as components of the aggregation/attachment pheromone or other pheromones is discussed.

Few biomarkers have been known that can easily measure clinical conditions in mental illnesses such as schizophrenia. Capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS) is a new method that can measure ionized and low-molecular-weight metabolites. To explore global metabolomic alterations that characterize the onset of schizophrenia and identify biomarkers, we profiled the relative and absolute concentrations of the plasma metabolites from 30 patients with first-episode schizophrenia (FESZ, four drug-naïve samples), 38 healthy controls and 15 individuals with autism spectrum disorders using CE-TOFMS. Five metabolites had robust changes (increased creatine and decreased betaine, nonanoic acid, benzoic acid and perillic acid) in two independent sample sets. Altered levels of these metabolites are consistent with well-known hypotheses regarding abnormalities of the homocysteine metabolism, creatine kinase-emia and oxidative stress. Although it should be considered that most patients with FESZ received medication, these metabolites are candidate biomarkers to improve the determination of diagnosis, severity and clinical stages, especially for FESZ.

Background Previously it has been shown that mechanical wounding, salinity and heat activated a 46 kDa and 44 kDa mitogen-activated protein kinases (MAPKs) in forage related grasses. Forage and turf related grasses are utilized in diverse environments where they are routinely subjected to herbicides and exposed to fire and volatiles after cutting, however very little is known concerning the perception or molecular responses to these different stresses or compounds. Results In the model grass species Lolium temulentum (Lt), a 46 kDa mitogen-activated protein kinase (MAPK) was activated in the leaves within 5 min and a 44 kDa MAPK 15 min after exposure to green leaf volatiles released from grass clippings. When the tips of leaves of Lt plants were scorched by fire, the 46 kDa MAPK and 44 kDa MAPK were rapidly activated within 5 min and 20 min respectively in the treated leaf, and 15 min systemically in an adjacent untreated tiller after exposure to fire. Nonanoic acid (pelargonic acid), a component in herbicides used on grasses, activated a 46 kDa MAPK in the treated leaves within 5 min of exposure and 15 min in systemic tissues. At concentrations normally used in the herbicides, nonanoic acid was found to only weakly activate the 44 kDa MAPK after an hour in treated leaves, but strongly activated it in the systemic tillers 30 min after treatment. Acetic acid, HCl and NaOH also were found to activate these MAPKs in treated tillers. Conclusion The rapid activation of these MAPKs to a wide range of stress stimuli, suggest that these MAPKs play a role in the perception and response to these stresses and compounds. The activation of the MAPK by green leaf volatiles indicates a role for these compounds in wound signaling in grasses. Electronic supplementary material The online version of this article (doi:10.1186/1756-0500-7-807) contains supplementary material, which is available to authorized users.

The growth of pollen tubes of Nicotiana tabacum cultured in a petri dish was divided into five stages by the behaviors of pollen tubes, vegetative nuclei (VNs), and generative cells (GCs). Pollen tubes continued to elongate during every stage. Colchicine, at a concentration of 1 mM, preferentially inhibited the movement of the VNs but not that of GCs. Nonanoic acid preferentially inhibited the movement of GCs. These results suggest that different mechanisms of movement exist between VNs and GCs.

A number of ‘free’ phenolic and simple fatty acid compounds of potentially high phytotoxicity have been isolated from Calluna heathland soil and identified by GC and GC-MS methods. Amongst these the aromatic acids o-hydroxybenzoic (salicylic), p-methoxybenzoic and benzoic acid are reported for the first time in ‘free’ form in soil, as are the fatty acids octanoic (caprylic), and decanoic (capric) acid both of which occur mostly in the hydroxy form. These short chain (C8 and C10) acids are known to have particularly strong phytotoxic properties. Hydroxynonanoic (pelargonic) acid was also extracted and identified. In addition to being phytotoxic these compounds have strong fungitoxic properties. Their potential effects in Calluna heathland soils are discussed from a physiological and ecological viewpoint.

Low-molecular-weight triacylglycerols have been isolated from the seed oil ofArtemisia absinthown in which one acyl radical is derived from ethanoic, propanoic, butanoic, pentanoic, hexanoic, heptanoic, octanoic, or nonanoic acid. Their main representatives are the ethanoyl and propanoyl derivatives, position 2 being occupied mainly by the ethanoyl radical. The isomers with a short acyl radical in position 2 make up 75% of the total of the low-molecular-weight triacylglycerides isolated.

Sixteen species of fungi were isolated from a park-land soil. When inoculated back into a sterilized sample of this soil three sporostatic factors, acetaldehyde, n-propanol and nonanoic acid were found to accumulate and the soil became inhibitory to the germination of test spores. The level of inhibition recorded could be explained wholly in terms of the prevailing levels of the identified sporostatic factors.