First observation on the predation of a non-arthropod species by a dung beetle species: The case of Canthon chalybaeus and the snail Bulimulus apodemetes.

We described, for the first time, a case of predation of a non-arthropod species by a dung beetle species. Canthon chalybaeus Blanchard, 1843 kills healthy individuals of the terrestrial snail Bulimulus apodemetes (D'Orbigny, 1835) showing an evident pattern of physical aggressiveness in the attacks using the dentate clypeus and the anterior tibiae. The description of this predatory behaviour was complemented with the analysis of the chemical secretions of the pygidial glands of C. chalybaeus, highlighting those main chemical compounds that, due to their potential toxicity, could contribute to death of the snail. We observed a high frequency of predatory interactions reinforcing the idea that predation in dung beetles is not accidental and although it is opportunistic it involves a series of behavioural sophistications that suggest an evolutionary pattern within Deltochilini that should not only be better studied from a behavioural point of view but also phylogenetically.

Identification of key odorant compounds in starch-based polymers intended for food contact materials.

Biopolymers used for food contact materials must be evaluated in order to ensure food safety and quality. In this work, the aroma profile of starch-based packaging materials, presented as pellets and films has been characterized. Headspace solid phase microextraction (HS-SPME) technique and gas chromatography coupled to both mass spectrometry and a sniffing port (GC-MS-O) were used for identification. In total, 35 odorant compounds were detected. The results showed that aldehydes were the odorants with the highest aromatic impact in starch-based films. Eight odorant compounds, such as trimethylamine, 1-octen-3-one, sotolon, (Z) and (E)-2-nonenal, p-vinylguaiacol, eugenol and 1-undecanol, defined as aroma-impact compounds, obtained modified frequency values (MF%) above 60% in at least 3 out of 4 films. A sensory panel evaluated the toasted, sweet/fruity, green, flower, distasteful, fat and spices notes in the films and it was observed that the quality of all samples decreased when the toasted and spices notes increased.

Isolation of Lactic Acid Bacteria Eliminating Trimethylamine (TMA) for Application to Fishery Processing.

Fishy odor of fish flesh (meat) presents a severe problem for marine production. The main cause of fishy odor is trimethylamine (TMA), which increases during storage. It is produced from trimethylamine oxide (TMAO), an osmosis-regulating substance in fish cells that functions by a reduction reaction. Bacterial growth in fish meat increases TMA. Its odor reduces the commercial value of the meat. Technologies for its regulation and elimination are desired. This chapter presents a description of the use of lactic acid to eliminate TMA. The lactic acid is producible safely by bacteria during food processing using picric acid-toluene.A method of eliminating TMA was demonstrated using Lactobacillus plantarum H78. Furthermore, an assay method was explained for reducing TMA in fish meat by fermenting the H78 strain.

Simultaneous HS-SPME GC-MS determination of short chain fatty acids, trimethylamine and trimethylamine N-oxide for gut microbiota metabolic profile.

Trimethylamine (TMA), trimethylamine-N-oxide (TMAO) and short chain fatty acids (SCFAs), as acetic, propionic, butyric and valeric acids are among the most important products of the gut microbiota (GM) metabolism. The present study is aimed at the determination of TMA, TMAO and SCFAs by a double step headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) analysis, allowing the simultaneous quantitation of both the acidic and basic metabolites in faecal samples. TMAO amount was evaluated after its reduction to TMA by using Fe(II)-EDTA complex as a reagent. Under the fully validated experimental conditions, adequate sensitivity (LOQ 0.011-0.23 µmol g-1), good accuracy (79 - 110%) and precision (CV% < 11%) were achieved for all the target analytes. The presented method is successfully applied to the quantitation of the considered gut metabolites in faecal samples from Italian healthy volunteers.

Nanostructured α-MoO3 thin film as a highly selective TMA sensor.

Molybdenum trioxide thin films of different thicknesses were prepared on a glass substrate with the chemical spray pyrolysis technique. The X-ray diffraction pattern indicates the formation of an α-MoO3 phase with a polycrystalline nature. The field-emission scanning electron micrograph of the surface indicates nanostructured lamellar crystallites. The trimethylamine vapour sensing property of the film was studied by the chemiresistive method at room temperature (≈ 30°C). Film with a thickness of 520 nm shows a response of 12% for 0.5 ppm of TMA vapour in 54% relative humidity, with response and recovery times of 32s and 15s, respectively. The detection limit and sensing response of the α-MoO3 thin film in a mixed environment were analysed and reported.

Simultaneous solid phase extraction and derivatization of aliphatic primary amines prior to separation and UV-absorbance detection.

To overcome the problem of poor sensitivity of capillary electrophoresis-UV absorbance for the detection of aliphatic amines, a solid phase extraction and derivatization scheme was developed. This work demonstrates successful coupling of amines to a chromophore immobilized on a solid phase and subsequent cleavage and analysis. Although the analysis of many types of amines is relevant for myriad applications, this paper focuses on the derivatization and separation of amines with environmental relevance. This work aims to provide the foundations for future developments of an integrated sample preparation microreactor capable of performing simultaneous derivatization, preconcentration, and sample cleanup for sensitive analysis of primary amines.

Novel one-step headspace dynamic in-syringe liquid phase derivatization-extraction technique for the determination of aqueous aliphatic amines by liquid chromatography with fluorescence detection.

A novel one-step headspace (HS) dynamic in-syringe (DIS) based liquid-phase derivatization-extraction (LPDE) technique has been developed for the selective determination of two short-chain aliphatic amines (SCAAs) in aqueous samples using high performance liquid chromatography (HPLC) with fluorescence detection (FLD). Methylamine (MA) and dimethylamine (DMA) were selected as model compounds of SCAAs. In this method, a micro-syringe pre-filled with derivatizing reagent solution (9-fluorenylmethyl chloroformate) in the barrel was applied to achieve the simultaneous derivatization and extraction of two methylamines evolved from alkalized aqueous samples through the automated reciprocated movements of syringe plunger. After the derivatization-extraction process, the derivatized phase was directly injected into HPLC-FLD for analysis. Parameters influencing the evolution of methylamines and the HS-DIS-LPDE efficiency, including sample pH and temperature, sampling time, as well as the composition of derivatization reagent, reaction temperature, and frequency of reciprocated plunger movements, were thoroughly examined and optimized. Under optimal conditions, detections were linear in the range of 25-500µgL(-1) for MA and DMA with correlation coefficients all above 0.995. The limits of detection (based on S/N=3) were 5 and 19ngmL(-1) for MA and DMA, respectively. The applicability of the developed method was demonstrated for the determination of MA and DMA in real water samples without any prior cleanup of the sample. The present method provides a simple, selective, automated, low cost and eco-friendly procedure to determine aliphatic amines in aqueous samples.

Ion chromatographic separation and quantitation of alkyl methylamines and ethylamines in atmospheric gas and particulate matter using preconcentration and suppressed conductivity detection.

Two methods based on ion chromatography (IC) were developed for the detection of methyl and ethyl alkyl amines (methylamine (MA), ethylamine (EA), dimethylamine (DMA), diethylamine (DEA), trimethylamine (TMA) and triethylamine (TEA)) and NH(3)/NH(4)(+) in online atmospheric gas-particle and size-resolved particulate samples. The two IC methods were developed to analyze samples collected with an ambient ion monitor (AIM), an online gas-particle collection system, or with a Micro Orifice Uniform Deposit Impactor (MOUDI) for size-resolved particle samples. These methods enable selective and (semi-) quantitative detection of alkyl amines at ambient atmospheric concentrations (pptv and pgm(-3)) in samples where significant interferences can be expected from Na(+) and NH(4)(+), for example marine and rural air masses. Sample pre-concentration using a trace cation column enabled instrumental detection limits on the order of pmol (sub-ng) levels per sample, an improvement of up to 10(2) over current IC methods. Separation was achieved using a methanesulfonic acid gradient elution on Dionex CS12A and CS17 columns. The relative standard deviations in retention times during 3 weeks continuous (hourly) sampling campaigns ranged from 0.1 to 0.5% and 0.2 to 5% for the CS12A and CS17 across a wide dynamic range of atmospheric concentrations. Resolution of inorganic and organic cations is limited to 25min for online samples. Mass-dependent coelution of NH(4)(+)/MA/EA occurred on the CS12A column and DEA/TMA coeluted on both columns. Calibrations of ammonium show a non-linear response across the entire calibration range while all other analytes exhibit high linearity (R(2)=0.984-0.999), except for EA and TEA on the CS12A (R(2)=0.960 and 0.941, respectively). Both methods have high analytical accuracy for the nitrogenous bases ranging from 9.5 to 20% for NH(3) and <5-15% for the amines. Hourly observations of amines at Egbert, ON in October 2010 showed gaseous DMA and TMA+DEA at 1-10pptv in air, while particulate DMA and TMA+DEA were present at 0.5-4ng m(-3). A size-resolved particulate sample collected over 23h was found to contain DMA, TMA+DEA and MEA at 1.78, 8.15 and 0.03ngm(-3) mass loadings, with the amine mass enhanced in particle sizes between 100 and 1000nm. These results highlight a need for very sensitive and selective detection of methyl and ethyl amines in addition to NH(3) in continuous online monitoring strategies.

(CdSe/ZnS QDs)-ionic liquid-based headspace single drop microextraction for the fluorimetric determination of trimethylamine in fish.

Here, we propose the use of ionic liquid-modified QDs for the combination of ionic liquid-based headspace single drop microextraction technique (IL-HS-SDME) and QD-based fluorimetric detection. In that way, we exploit the advantages of ILs as extractant solvent and the use of QDs as fluorescence detection probe. After in situ generation of volatile trimethylamine (TMA) from fish samples, the analyte was extracted and preconcentrated directly onto a (QD)IL microdrop by HS-SDME. Then, TMA was quantified through the enhancing effect produced on the initial fluorescence of the (QD)IL dispersion. The working conditions for the (QD)IL-HS-SDME procedure were: 20 µL microdrop of (QD)IL exposed for 2 min to the headspace of a 5 mL aqueous sample (0.2 g of fish in 10 M NaOH) placed in a 10 mL vial with stirring and thermostatted at 50-60 °C. For the detection, the microdrop was transferred to a microcuvette with 300 µL of acetonitrile and the fluorescence was recorded (λ(em) = 570 nm, λ(exc) = 400 nm). Under the selected conditions, the analytical response was linear over the range from 0.05 to 0.25 mg L(-1) (R(2) = 0.997) with a detection limit of 0.014 mg L(-1) (0.35 µg TMA per gram of fish) and the relative standard deviation was 3.5% (n = 5). The proposed method was applied to the determination of TMA in hake fish samples with satisfactory results.

Identification and regulation of novel compatible solutes from hypersaline stromatolite-associated cyanobacteria.

Cyanobacteria are able to survive in various extreme environments via the production of organic compounds known as compatible solutes. In particular, cyanobacteria are capable of inhabiting hypersaline environments such as those found in intertidal regions. Cyanobacteria in these environments must possess regulatory mechanisms for surviving the changing osmotic pressure as a result of desiccation, rainfall and tidal fluxes. The objective of this study was to determine the compatible solutes that are accumulated by cyanobacteria from hypersaline regions, and specifically, the stromatolite ecosystems of Shark Bay, Western Australia. Previously, the cyanobacterial populations associated with these stromatolites were characterized in two separate studies. Compatible solutes were extracted from isolated cyanobacteria here and identified by nuclear magnetic resonance. As the media of isolation contained no complex carbon source, the solutes accumulated were likely synthesized by the cyanobacteria. The data indicate that from this one habitat taxonomically distinct cyanobacteria exposed to varying salinities accumulate a range of known compatible solutes. In addition, taxonomically similar cyanobacteria do not necessarily accumulate the same compatible solutes. Glucosylglycerol, a compatible solute unique to marine cyanobacteria was not detected; however, various saccharides, glycine betaine, and trimethylamine-N-oxide were identified as the predominant solutes. We conclude that the cyanobacterial communities from these hypersaline stromatolites are likely to possess more complex mechanisms of adaptation to osmotic stress than previously thought. The characterization of osmoregulatory properties of stromatolite microorganisms provides further insight into how life can thrive in such extreme environments.

Removal of trimethylamine by adsorption over zeolite catalysts and deodorization of fish oil.

Trimethylamine (TMA) is the main agent for the odor often associated with fouling fish, some infections, and bad breath. This study focused on the adsorption of TMA over various microporous zeolites for application in the low-temperature deodorization of fishy odor from raw fish oil. The faujasite (Si/Al=3) zeolite exhibited the high adsorption ability, which, in combination with its wide surface area and pore volume, may have induced the high adsorption ability. The H-mordenite (Si/Al=10) zeolite exhibited a large TMA adsorption. It was considered to have generated more attractive adsorption with TMA ions, because TMA interacted briskly with cations of acid sites on the zeolites. The fishy odor of raw fish oil was considerably reduced by low-temperature adsorption on the zeolites. The surface area of the zeolites retained most of the TMA adsorption ability, and their acid strength further enhanced the adsorption ability.

Biofiltration of trimethylamine, dimethylamine, and methylamine by immobilized Paracoccus sp. CP2 and Arthrobacter sp. CP1.

A biofilter using granular activated carbon with immobilized Paracoccus sp. CP2 was applied to the elimination of 10-250 ppm of trimethylamine (TMA), dimethylamine (DMA), and methylamine (MA). The results indicated that the system effectively treated MA (>93%), DMA (>90%), and TMA (>85%) under high loading conditions, and the maximum degradation rates were 1.4, 1.2, and 0.9g-Nkg(-1) GAC d(-1). Among the three different amines treated, TMA was the most difficult to degrade and resulted in ammonia accumulation. Further study on TMA removal showed that the optimal pH was near neutral (6.0-8.0). The supply of high glucose (>0.1%) inhibited TMA removal, maybe due to substrate competition. However, complete TMA degradation was achieved under the co-immobilization of Paracoccus sp. CP2 and Arthrobacter sp. CP1 ( approximately 96%). Metabolite analysis results demonstrated that the metabolite NH(4)(+) concentrations decreased by a relatively small 27% while the metabolite NO(2)(-) apparently increased by heterotrophic nitrification of Arthrobacter sp. CP1 in the co-immobilization biofilter.

Off-flavors removal and storage improvement of mackerel viscera by supercritical carbon dioxide extraction.

The oil in mackerel viscera was extracted by supercritical carbon dioxide (SCO2) at a semi-batch flow extraction process and the fatty acids composition in the oil was identified. Also the off-flavors removal in mackerel viscera and the storage improvement of the oils were carried out. As results obtained, by increasing pressure and temperature, quantity was increased. The maximum yield of oils obtained from mackerel viscera by SCO, extraction was 118 mgg(-1) (base on dry weight of freeze-dried raw anchovy) at 50 degrees C, 350 bar And the extracted oil contained high concentration of EPA and DHA. Also it was found that the autoxidation of the oils using SCO2 extraction occurred very slowly compared to the oils by organic solvent extraction. The off-flavors in the powder after SCO2 extraction were significantly removed. Especially complete removal of the trimethylamine which influences a negative compound to the products showed. Also other significant off-flavors such as aldehydes, sulfur-containing compounds, ketones, acids or alcohols were removed by the extraction.

Treatment of waste gas containing monomethylamine in a biofilter enriched with Pseudomonas mendocina.

Waste gas containing monomethylamine (MMA) was treated in a biofilter packed with compost along with wood chips and enriched with Pseudomonas mendocina. The biofilter could remove MMA to the extent of more than 99% at a loading of 42.36 gm(-3)h(-1) with an empty bed retention time of 12s. At optimal operating conditions, the moisture content in the biofilter was maintained at around 45%. The biodegradative products of MMA were ammonia, nitrite, and nitrate.

Precursors of N-nitroso compounds in some Nigerian medicinal plants.

Twenty-seven tropical plants of medicinal importance were analysed for primary and secondary amines by chemiluminescence detection on a Thermal Energy Analyzer (TEA) modified for use on 'nitrogen mode' following derivatization with benzene sulphonyl chloride (BSC) and gas chromatographic (GC) separation of their sulphonamides. Nitrite was determined by colorimetry at 540 nm after diazotization with sulphanilamide and coupling with N-(1-naphthyl)ethylenediamine to form an azo dye. Nitrate was determined as nitrite following on-line reduction by granulated cadmium. Dimethylamine in the range of 0.5 ppm to 18.2 ppm was detected in 96% of samples, while pyrrolidine ranged between 0.7 ppm and 12.78 ppm in 14 samples. Isobutylamine, methylamine and ethylamine were the most ubiquitous primary amines. Largest number of secondary amines (four) was found in Azadirachta indica (Neem) while largest number of primary amines (six) was detected in Azadirachta indica and Tamarindus indica (Tsamiya) which also contained the highest amount of total primary amines (148.8 ppm). Nitrate and nitrite were seldom found in plant extracts whose pH were generally below 7.0. These findings suggests that early exposures to precursors of N-nitroso compounds via medicinal plants might contribute to total risk posed by environmental carcinogens in Nigeria.

Chromatographic separation of choline, trimethylamine, trimethylamine oxide, and betaine from tissues of marine fish.

A chromatographic procedure using sequential ion-exchange columns is described for separating choline, trimethylamine, trimethylamine oxide, and betaine extracted from marine fish tissues; added exogenous carnitine can also be separated by the system. Choline with its positive charge binds to the AG 50W-X8 (Na+, pH 9) column. The column is first eluted with 0.1 N NaOH to collect trimethylamine, trimethylamine oxide, and betaine; choline is then eluted with 0.5 N NaOH. The amines collected with 0.1 N NaOH are subsequently separated using an AG 50W-X8 (H+, pH 4) column eluted with a linear 0-1 M NaC1 gradient.

Gas chromatographic analysis of bacterial amines as their free bases.

Columns of Chromosorb 103, Tenax-GC, Amine 220 plus potassium hydroxide on Chromosorb W, and Carbowax 20M plus potassium hydroxide on Chromosorb W were compared for their ability to separate bacterial amines as their free bases in aqueous solution. A 1.52 m X 0.6 cm O.D. column of Chromosorb 103 separated eleven amines when operated isothermally at 185 degrees C. A further four high-boiling amines could be separated at 240 degrees C. The other packings separated only eight amines isothermally, except for Tenax-GC which separated seven of the free bases. Chromosorb 103 performed less well than Carbowax 20 M plus potassium hydroxide with respect to number of plates or peak resolution. The maximum number of amines separated, thirteen, required Chromosorb 103 programmed from 170 degrees C to 230 degrees C at 3 degrees C min-1 after an initial holding time of 20 min. It was possible tentatively to identify amines in culture supernatant fluid of Proteus mirabilis, viz. ethylamine, isobutylamine and isoamylamine, after direct injection of culture supernatant fluid.

Faecal methylamine in normal and uraemic subjects.

1. A ninhydrin-reacting substance seen during ion-exchange chromatography of faecal dialysate obtained in vivo from normal and uraemic subjects has been isolated and identified as methylamine. 2. Faecal dialysate concentrations of methylamine were higher in uraemic subjects and were related to the degree of renal impairment (P less than 0.05). 3. Methylamine concentrations in faecal dialysate and centrifugate were not significantly different.