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Marine microalgae often live in a fluctuating environment including a decrease in salinity caused by global warming induced sea ice melting and freshwater inflows. Under conditions of fluctuating salinity, microalgae have evolved a variety of survival mechanisms such as lipid accumulation and remodeling. The purpose of this study was to investigated the membrane lipid remodeling of the marine green microalgaDunaliella tertiolectaas a short-term acclimation mechanism in response to hyposalinity (20 and 3 PSU) with respect to growth at optimal salinity (38 PSU). We identified 34 lipid species belonging to seven polar lipid classes.Dunaliella tertiolectaaccumulates cell lipids and remodels polar lipid classes and their fatty acids composition as response to hypoosmotic stress at 3 PSU. We found that the unsaturation of most polar lipids decreases overall, indicating decreased membrane fluidity and altered permeability, whereas shortening the length of fatty acids of polar lipids is not one of the strategies ofD. tertiolectato cope with the decrease in salinity. Increase in relative content (%) and unsaturation of monogalactosyldiacylglycerols (MGDG) and decrease in relative content (%) and unsaturation of phosphatidylglycerols (PG), suggesting changes in photosynthetic membranes of thylakoids at 20 and 3 PSU. At a very low salinity of 3 PSU, the relative content (%) of phosphatidylinositols (PI) increases, suggesting increased lipid trafficking and signaling in the cells. These changes are statistically significant and we hypothesize thatD. tertiolectais genetically adapted to withstand large salinity fluctuations through polar lipid composition.

Aflatoxins are considered to be a critical dietary risk factor for humans, with aflatoxin B1 (AFB1) identified by the WHO as one of the most potent natural group 1 carcinogen. Despite this, more than half of the world's population is chronically exposed, resulting in up to 170,000 annual cases of human hepatocellular carcinoma cancer. Here we report an easily implemented approach using non-equilibrium plasma for targeted degradation of AFB1. Apart from reaching the 100 % decontamination in less than 120 s of treatment, this is the first study that combines hypersensitive analytical methods such as high-resolution mass spectroscopy (HRMS) and nuclear magnetic resonance spectroscopy (NMR) to provide a detailed description of CAP mediated AFB1 degradation. We identify rapid scission of the vinyl bond between 8- and 9-position on the terminal furan ring of AFB1 as being of paramount importance for the suppression of toxic potential, which is confirmed by the examination of both cytotoxicity and genotoxicity. The plasma reactive species mediated degradation pathways are elucidated, and it is demonstrated that the approach not only renders AFB1 harmless but does so in order of magnitude less time than UV irradiation as one of the other non-thermal methods currently under investigation.

Aflatoxins are considered to be a critical dietary risk factor for humans, with aflatoxin B

Lignans are generally known for their beneficial impact on human health. In this study, we found that the water extract of silver fir (Abies alba) wood contains lignans, which constitute approximately 10% of the extract and include isolariciresinol, hydroxymatairesinol, secoisolariciresinol, lariciresinol, pinoresinol, and matairesinol. The antioxidant activity of the extract was measured by several in vitro assays and an assay in a eukaryotic cell model (yeast). The extract had greater in vitro antioxidative activity than ascorbic acid, resveratrol, or butylated hydroxytoluene (BHT) and similar antioxidative activity to epigallocatechin gallate. The intracellular antioxidant effect in the yeast gave indirect evidence that the components of the silver fir wood extract (SFWE) effectively pass through eukaryotic cell membranes and have higher in vivo antioxidative activity than ascorbic acid, resveratrol, tocopheryl succinate, or BHT and similar to epigallocatechin gallate. The in vitro gastrointestinal dig...

Elevated expression of the immunoproteasome has been associated with autoimmune diseases, inflammatory diseases, and various types of cancer. Selective inhibitors of the immunoproteasome are not only scarce, but also almost entirely restricted to peptide-based compounds. Herein, we describe nonpeptidic reversible inhibitors that selectively block the chymotrypsin-like (β5i) subunit of the human immunoproteasome in the low micromolar range. The most potent of the reversibly acting compounds were then converted into covalent, irreversible, nonpeptidic inhibitors that retained selectivity for the β5i subunit. In addition, these inhibitors discriminate between the immunoproteasome and the constitutive proteasome in cell-based assays. Along with their lack of cytotoxicity, these data point to these nonpeptidic compounds being suitable for further investigation as β5i-selective probes for possible application in noncancer diseases related to the immunoproteasome.

Mycotoxins, the toxic secondary metabolites produced by filamentous fungi, are found in up to 80% of global food and feed crops. Here, we report on the complete removal of aflatoxin B1 (AFB 1 ) from the artificially contaminated corn kernels with an indirect cold atmospheric pressure plasma (CAP) treat- ment generated with a surface barrier discharge system working in ambient air. Surface analysis of the corn kernels revealed the pre- sence of minor changes in the treated samples, indicating that indirect CAP treatments induced slight oxidation of the corn kernel surface. This study not only proposes CAP as an effective food processing method for the decontamina- tion of mycotoxins but also presents the first step towards acceptance of CAP technology as a safe food processing method.

ATP competitive inhibitors of DNA gyrase and topoisomerase IV have great therapeutic potential, but none of the described synthetic compounds has so far reached the market. To optimise the activities and physicochemical properties of our previously reported N-phenylpyrrolamide inhibitors, we have synthesized an improved, chemically variegated selection of compounds and evaluated them against DNA gyrase and topoisomerase IV enzymes, and against selected Gram-positive and Gram-negative bacteria. The most potent compound displayed IC50 values of 6.9%nM against Escherichia coli DNA gyrase and 960%nM against Staphylococcus aureus topoisomerase IV. Several compounds displayed minimum inhibitory concentrations (MICs) against Gram-positive strains in the 1-50%%M range, one of which inhibited the growth of Enterococcus faecalis, Enterococcus faecium, S. aureus and Streptococcus pyogenes with MIC values of 1.56%%M, 1.56%%M, 0.78%%M and 0.72%%M, respectively. This compound has been investigated further on methicillin-resistant S. aureus (MRSA) and on ciprofloxacin non-susceptible and extremely drug resistant strain of S. aureus (MRSA VISA). It exhibited the MIC value of 2.5%%M on both strains, and MIC value of 32%%M against MRSA in the presence of inactivated human blood serum. Further studies are needed to confirm its mode of action. Bibliografija: str. 289-290. Abstract. ARRS Academy of Finland Academy of Finland Academy of Finland European Research Council, Resistance Evolution GINOP GINOP PhD fellowship from the Boehringer Ingelheim Fonds

Benzotriazoles (BTs) are regarded as contaminants of emerging concern. However, their transformation products (BTTPs) in aquifers remains poorly characterized. The present study is the first detailed report on profiles of the BTTPs in an urban oxic intergranular aquifer related to water type, land use and the aquifer's depth. The 2-methyl-2H-benzotriazole (2-MeBT) and 2,4-dimethyl-2H-benzotriazole (2,4-dMeBT) were quantified using the gas chromatography–mass spectrometry (GC–MS) analytical technique based on internal standards. For the first time the relationship between the 2-MeBT and 2,4-dMeBT concentrations was studied in sampled water and discussed with respect to the different flow paths and sources of contamination. Three main sources of BTTPs were determined in urban groundwater: BTs and BTTPs included in the outflow of effluents from wastewater-treatment plants and energy-producing facilities into surface streams that recharge the aquifer and in the leaking effluents from industrial and public wastewater pipelines. The results confirm that the BTTPs are transformed from parent compounds in the aquifer's unsaturated zone in the case when the effluents are temporally stored in sediments with a lower hydraulic conductivity, which is indicated with the highest median concentrations of BTTPs referring to the perched aquifers where the BTTPs proportions were 92–99%. BTTPs dominated over the parent BTs also in groundwater. The highest concentrations of BTTPs (up to 174 and 144 ng L−1 for the 2-MeBT and 2,4-dMeBT ng L−1, respectively) were measured in groundwater abstracted from the upper parts of the aquifer in the area where the losses from industrial wastewater pipelines were evidenced. The 2,4-dMeBT dominated over the 2-MeBT in the BTTPs originating from BTs included in the industrial effluents, which is the opposite to the case when their origin is in the municipal effluents. The median sum concentration of the BTTPs in drinking-water resources (2.0 ng L−1) is lower than the quality criterion recommended for BTs so far. Nevertheless, the abundance of BTs in the environment and the apparent environmental relevance of the BTTPs in urban groundwater indicate the need for a risk assessment of BTTPs with respect to health and the environment.

Diabetes mellitus is one of the leading world’s public health problems. Therefore, it is of a huge interest to develop new antidiabetic drugs. Apart from traditional therapy of diabetes, nowadays, importance is given to natural substances with antidiabetic potential. Fomes fomentarius is a mushroom widely used for different purposes, due to its range of already confirmed activities. Fomentariol is a constituent of Fomes fomentarius, responsible for its antidiabetic potential. In that respect, it is important to develop a method for isolation and quantification of fomentariol from fungal material, which will be simple and efficient. Multistep, complex extraction applied in the previously reported studies was avoided with ethanol, providing rapid single-step extraction. The presence of fomentariol in ethanolic extract was confirmed by high-resolution mass spectrometry. Semipreparative HPLC method was developed and applied for isolation from ethanol extract and purification of the active compound fomentariol. It was a gradient reversed-phase method with a mobile phase consisting of acetonitrile and 0.1% formic acid in water and total run time of 15 minutes. The amount of 6.5 mg of high-purity fomentariol was determined by quantitative NMR with toluene as internal standard. The isolated and determined amount of substance can be further used for the quantitative estimation of activity of fomentariol.

Benzotriazoles (BTs) are considered as Contaminants of Emerging Concern (CECs); however, information about their fate in aquifers continues to be absent. This was the focus of the present study, which provides the first evidence for relevant BTs' degradation products (BTTPs) in urban aquifers that may impact the groundwater quality. The mechanisms and biotransformation pathways of BTs were investigated in an oxic intergranular medium. The BTs and BTTPs were identified and quantified by gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–mass spectrometry (LC–MS) analytical techniques based on reference standards and internal materials. The major transformation products were identified as 2-methyl-2H-benzotriazole (2-MeBT) for the degradation of 1H-benzotriazole (BT) and as 2,4-dimethyl-2H-benzotriazole (2,4-dMeBT) and 1,4-dimethyl-1H-benzotriazole (1,4-dMeBT) for the degradation of 4-methyl-1H-benzotriazole (4-MeBT), and most probably also 5-methyl-1H-benzotriazole (5-MeBT). The leakage of wastewater pipelines is most probably the source of BTs. Sediments with a lower hydraulic conductivity give rise to perched aquifer conditions that lead to the temporal storage of leaking effluents and presumably the majority of BTs' transformation processes via methylation and tautomerization. The most stable BTTPs entered the saturated zone of the aquifer, where they prevailed. Concentrations up to 1500 ng L−1 were measured for the 2,4-dMeBT, which suggest a contamination risk for groundwater that is or may be used as a source for drinking water in the case of a constant input of pollutant loads from sewer systems.

Buckwheat products are commonly used in health foods and food supplements. However, public awareness regarding the presence of photodynamic naphthodianthrones fagopyrins that can cause photosensitization is low. At least two additional compounds with structures similar to that of fagopyrin are known to exist; however, the structures of these compounds have never been determined. In this work, we improved the extraction procedure and the chromatographic analysis of fagopyrins by developing a simple, sensitive and high-resolution high performance liquid chromatography (HPLC) analytical method using fluorescence detection. We observed at least six fagopyrin derivatives, which were isolated and characterized via UV–Vis absorption, NMR spectroscopy and mass spectrometry. We determined the structures of two new derivatives (fagopyrin A and fagopyrin E) and proved the existence of protofagopyrins that can transform into fagopyrins upon light exposure. Our methods complement the existing knowledge regarding fagopyrins and will allow for their further analysis, isolation and investigation of their biological activity.

Extracts from the bark of different conifer species are known to contain various polyphenols and possess interesting pharmacological activities. So far the most extensive research was done on the antioxidative extract of the maritime pine (Pinus maritima) bark, which is widely used in food supplements and cosmetic products. Here we have shown, that antioxidant activity of silver fir (Abies alba) bark extract is higher than of maritime pine bark extract in cultured cells. Components of the extract were separated with normal phase flash chromatography and reversed phase high-performance liquid chromatography (HPLC). The structures of individual compounds were identified by mass spectrometry, UV–vis absorption spectroscopy and comparison to reference compounds. Six phenolic acids were identified (gallic, homovanillic, protocatehuic, p-hydroxybenzoic, vanillic and p-coumaric), three flavonoids (catechin, epicatechin and catechin tetramethyl eter) and four lignans (taxiresinol, 7-(2-methyl-3,4-dihydroxytetrahydropyran-5-yloxy)-taxiresinol, secoisolariciresinol and laricinresinol).

5-Fluorouracil (5-FU) is a fluorinated pyrimidine analogue important in the treatment of cancer whose fate in the environment is yet to be fully addressed. Due to its high polarity 5-FU requires challenging sample preparation and therefore we thoroughly investigated different solid phase extraction mechanisms (ion pair, ion exchange, reversed phase), sorbents and derivatisation agents to enable trace-level analysis of 5-FU based on GC-MS/MS in natural and wastewaters. Ion pair and ion exchange retention mechanisms enable the extraction of 5-FU from deionised water, but were inappropriate for complex environmental matrices, where the reversed phase sorbent Isolute ENV+ gave the best extraction efficiencies (53% and 93% for wastewaters and surface waters, respectively). Further, alkylation was rejected in favour of silylation with MTBSTFA. The achieved limits of quantification (LOQ) for waste and surface waters were 1.6 ng/L and 0.54 ng/L, respectively. The method was used to analyse samples of hospital, wastewater treatment plant influent and effluent and surface waters. 5-FU was quantified in four out of the twelve samples of oncological ward wastewaters and municipal wastewater treatment plant influents in concentrations from 4.7 ng/L to 92 ng/L. This work is also the first to study the environmental transformation of 5-FU and its prodrug capecitabine (CAP). Their removal and transformation was simulated using a series of biodegradation and photodegradation experiments, where 5-FU proved more degradable in comparison to CAP. Transformation of 5-FU and CAP was studied by using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QqTOF). Overall, six transformation products for 5-FU and ten for CAP are proposed; 13 of these are to our knowledge published for the first time.

In the last couple of decades fungal infections have become a significant clinical problem. A major interest into fungal steroid action has been provoked since research has proven that steroid hormones are toxic to fungi and affect the host/fungus relationship. Steroid hormones were found to differ in their antifungal activity in ascomycetous fungi Hortaea werneckii, Saccharomyces cerevisiae and Aspergillus oryzae. Dehydroepiandrosterone was shown to be the strongest inhibitor of growth in all three varieties of fungi followed by androstenedione and testosterone. For their protection, fungi use several mechanisms to lower the toxic effects of steroids. The efficiency of biotransformation in detoxification depended on the microorganism and steroid substrate used. Biotransformation was a relatively slow process as it also depended on the growth phase of the fungus. In addition to biotransformation, steroid extrusion out of the cells contributed to the lowering of the active intracellular steroid concentration. Plasma membrane Pdr5 transporter was found to be the most effective, followed by Snq2 transporter and vacuolar transporters Ybt1 and Ycf1. Proteins Aus1 and Dan1 were not found to be involved in steroid import. The research of possible targets of steroid hormone action in fungi suggests that steroid hormones inhibit ergosterol biosynthesis in S. cerevisiae and H. werneckii. Results of this inhibition caused changes in the sterol content of the cellular membrane. The presence of steroid hormones most probably causes the degradation of the Tat2 permease and impairment of tryptophan import.

Nickel (Ni) is considered to be a potentially harmful element for humans. Its levels in foodstuffs are normally low (below 0.2mgkg-1), but sensitive individuals may develop allergy to Ni as a result of dietary consumption. Cocoa contains relatively high Ni concentrations (around 3mgkg-1). Ni bioavailability, its role in the flavour of food and its potential impact on human health depends primarily on its chemical species. However, there is a lack of information about Ni speciation in cocoa. In this work Ni species were separated on a weak convective interaction media diethylamine (CIM DEAE) monolithic chromatographic column and quantified by the post-column isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS). The Ni binding ligands in the separated fractions were identified "off line" by quadrupole time-of-flight mass spectrometry (Q-TOF MS). Ni was found to be present in the cocoa infusions as Ni2+ and Ni-gluconate and Ni-citrate complexes.

In human milk zinc (Zn) is bound to proteins and low molecular mass (LMM) ligands. Numerous investigations demonstrated that Zn bioavailability in human milk is for infant much higher than in cow's milk. It was presumed that in the LMM human milk fraction highly bioavailable Zn-citrate prevails. However, literature data are controversial regarding the amount of Zn-citrate in human milk since analytical procedures reported were not quantitative. So, complex investigation was carried out to develop analytical method for quantitative determination of this biologically important molecule. Studies were performed within the pH range 5-7 by the use of synthetic solutions of Zn-citrate prepared in HEPES, MOPS and MES buffers. Zn-citrate was separated on weak anion-exchange convective interaction media (CIM) diethylaminoethyl (DEAE) monolithic chromatographic column using NH(4)NO(3) as an eluent. Separated Zn species were determined by flame atomic absorption spectrometry (FAAS) or inductively coupled plasma mass spectrometry (ICP-MS). Quantitative separation of Zn-citrate complexes ([Zn(Cit)](-) and [Zn(Cit)(2)](4-); column recoveries 94-102%) and good repeatability and reproducibility of results with relative standard deviation (RSD±3.0%) were obtained. In fractions under the chromatographic peaks Zn-binding ligand was identified by electrospray ionization tandem mass spectrometry (ESI-MS-MS). Limits of detection (LOD) for determination of Zn-citrate species by CIM DEAE-FAAS and CIM DEAE-ICP-MS were 0.01 μg Zn mL(-1) and 0.0005 μg Zn mL(-1), respectively. Both techniques were sensitive enough for quantification of Zn-citrate in human milk. Results demonstrated that about 23% of total Zn was present in the LMM milk fraction and that LMM-Zn corresponded to Zn-citrate. The developed speciation method represents a reliable analytical tool for investigation of the percentage and the amount of Zn-citrate in human milk.

Benzodiazepine derivatives are prescribed in large quantities globally and are potentially new emerging environmental contaminants. Unfortunately, a dearth of data exists concerning occurrence, persistence and fate in the environment. This paper redresses this by reviewing existing literature, assessing the occurrence of selected benzodiazepine anxiolytics (diazepam, oxazepam and bromazepam) in wastewater influent and effluent and surface water from Slovenia, evaluating their removal during water treatment and identifying the transformation products formed during water treatment. Their occurrence was monitored in hospital effluent, river water and in wastewater treatment plant influent and effluent. The study reveals the presence of benzodiazepine derivatives in all samples with the highest amounts in hospital effluents: 111 ng L −1 , 158 ng L −1 and 72 ng L −1 for diazepam, bromazepam and oxazepam, respectively. Removal efficiencies with respect to biological treatment of diazepam were 16–18% (oxic), 18–32% (anoxic → oxic), 53–76% (oxic → anoxic) and 83% (oxic → anoxic → oxic → anoxic cascade bioreactors), while the removal oxazepam was 20–24% under anoxic conditions. Coupled biological and photochemical treatment followed by the adsorption to activated carbon resulted in a removal efficiency of 99.99%. Results reveal the recalcitrant nature of benzodiazepine derivatives and suggest that only combinational treatment is sufficient to remove them. In addition, eight novel diazepam and four novel oxazepam transformation products are reported.

The saprophytic fungus Rhizopus nigricans constitutes a serious problem when thriving on gathered crops. The identification of any compounds, especially natural ones, that inhibit fungal growth, may therefore be important. During its life cycle, Rhizopus nigricans encounters many compounds, among them the flavonoids, plant secondary metabolites that are involved in plant defense against pathogenic microorganisms. Although not being a plant pathogen, Rhizopus nigricans may interact with these compounds in the same way as plant pathogens--in response to the fungitoxic effect of flavonoids the fungi transform them into less toxic metabolites. We have studied the interaction of R. nigricans with some flavonoids. Inhibition of hyphal spreading (from 3% to 100%) was observed by 300 μM flavones, flavanones and isoflavones, irrespective of their basic structure, oxidized or reduced C-ring, and orientation of the B-ring. However, a hydrophobic A-ring was important for the toxicity. R. nigricans transformed some of the flavonoids into glucosylated products. Recognition of substrates for glucosylating enzyme(s) did not correlate with their fungitoxic effect but depended exclusively on the presence of a free -OH group in the flavonoid A-ring and of a hydrophobic B-ring. Although the fungus produced glucosyltransferase constitutively, an additional amount of the enzyme was induced by the substrate flavonoid. Moreover, effective detoxification was shown to require the presence of glucose.

Two new glyceroglycolipids as well as three known ones were isolated from the glyceroglycolipids molecular species obtained from two less polar fractions of the MeOH extract of the plant Euphorbia nicaeensis All. using normal and reversed phase column flash chromatography. The structures of the isolated glyceroglycolipids were determined on the basis of chemical and spectroscopic evidences. Two new glyceroglycolipids were isolated for the first time from Euphorbiaceae, 2 was assigned as (2S)-2,3-O-di-(hexadecanoyl)-glyceryl-β-D-galactopyranoside and 5 as (2S)-3-O-(9, 12- octadecadienoyl)-glyceryl-β-D-galactopyranoside. The isolated glyceroglycolipids exhibited an interesting anti-inflammatory activity.

The fungal biotransformation of steroids is of applied interest due to the economic importance of such stereo- and regiospecific reactions and also in the context of ergosterol pathway engineering to produce vitamin D and steroidal products. In Schizosaccharomyces pombe no steroid hydroxylation as is found in filamentous fungi was observed, but a cytosolic NAD(H)/NADP(H)-dependent hydroxysteroid dehydrogenase activity was identified. Progesterone was reduced at the Δ4 double bond (in vivo only) as well as at the C-3 and C-20 keto groups. Testosterone and 4-androstene-3,17-dione were interconverted and 5α-pregnane-3,20-dione and 5β-pregnane-3,20-dione were reduced to 3-hydroxy products. The reactions were sometimes reversible and showed regio- and stereo specificity. In S. pombe more than one steroid dehydrogenase homologue is likely to occur, as has been observed in Saccharomyces cerevisiae. Our findings indicate that genes encoding soluble proteins should be examined as candidates for actual steroid dehydrogenase activity. Copyright © 1999 John Wiley & Sons, Ltd.

The steroid hormones testosterone, androstenedione, progesterone and their metabolic products testosterone acetate and testololactone were identified as endogenously synthesised molecules in the fungus Pleurotus ostreatus . We discuss the possible steroidogenic pathway in the fungus in view of the evolutionary origin of the steroid hormone signalling system.

The structures and reactivities of protonated metastable and collision-activated molecules of isomeric N7- and N9-substituted purines were investigated using fast atom/ion bombardment ionization and mass analysed ion kinetic energy spectrometry methods. Calculated proton affinities (PAs) of isomeric purine derivatives and the intensities of the observed metastable-ion peaks revealed a direct correlation of PA with the reactivity of protonated molecules. The reactivity of the N9-substituted purines possessing N3-site specific proton affinities, i.e. N3–H+, relates to the strength of hydrogen bonding of N3–H+ to oxygen atoms(s) of the N9-substituent, e.g. CH2—O—CH2CH2—O—C(CH3) = O or CH2—OCH2CH2—O—H. Various intramolecular (‘intra-ion’) hydrogen-bond(s) in the protonated molecules of isomeric purine derivates were revealed using proton affinities and metastable-ion peak intensities. © 1997 John Wiley & Sons, Ltd.

Mass spectral measurements of complex ions MX+ formed from a bicyclic-molecule (M), which comprises a macroheterocyclic crown ether and a polyoxyethylene chain linked with two thioamido groups on a diaza-3n-crown-n-poly-ether, together with an X+ ion (X=H, Li or K) are discussed. The use of fast-atom/ion bombardment mass spectra and particularly collision-induced dissociation and mass-analysed ion kinetic energy spectra enabled an estimate of the site of the localization of X+ and the relative bond strength inside the collisionally-activated host–guest complex ion in the gas phase to be made.

Fast atom/ion bombardment mass spectrometry was used to investigate the structures of protonated molecules of macrocyclic nitrogen-containing crown ethers with two polyoxyethylene chains linked by two thiourea groups. The collision-induced dissociation (CID) of their MH+ ions, using the mass analysed ion kinetic energy (MIKE) spectrometry method reveals four clearly defined competitive fragmentations. The product-ion intensities clearly show that, in the MH+ ions of asymmetric crown ethers, the proton is preferentially located in the region of the longer polyoxyethylene chain. The characteristics of CID MIKE spectra of isomeric crown ethers are discussed.

The pottery assemblage from the Maharski prekop site was analysed to obtain insights into vessel use and husbandry practices. Total lipid extracts of pottery samples were subjected to gas chromatography (GC), gas chromatography–mass spectrometry (GC–MS), gas chromatography–combustion–isotope ratio mass spectrometry (GC–C–IRMS) and soft ionisation electrospray mass spectrometric techniques ESI Q–TOF MS and ESI Q–TOF MS/MS. The charred organic deposits on vessels were AMS 14C dated. The results show that some vessels were used for cooking ruminant meat, while in other traces of mixed non–ruminant and ruminant meat or plants and animal meat cooking were identified. Some vessels were used for milk processing.

For humans, Ni is not considered to be an essential trace element. Its compounds, at levels present in foodstuffs and drinks, are generally considered to be safe for consumption, but for individuals who already suffer from contact allergy to Ni and may be subject to develop systemic reactions from its dietary ingestion, dietary exposure to Ni must be kept under control. Being the second most popular beverage, tea is a potential source of dietary Ni. Present knowledge on its speciation in tea infusions is poor. Therefore, complete speciation analysis, consisting of separation by liquid chromatography using a weak CIM DEAE-1 monolithic column, "on-line" detection by inductively coupled plasma mass spectrometry (ICP-MS) and "off-line" identification of ligands by hybrid quadrupole time-of-flight mass spectrometry (Q-TOF MS), was implemented for the first time to study Ni speciation in tea infusions. Total concentrations of Ni in dry leaves of white, green, oolong and black tea (Camellia sinensis) and flowers of herbal chamomile (Matricaria chamomilla) and hibiscus (Hibiscus sabdariffa) tea were determined after microwave digestion by ICP-MS. They lay between 1.21 and 14.4 mg kg(-1). Good agreement between the determined and the certified values of the Ni content in the standard reference material SRM 1573a tomato leaves confirmed the accuracy of the total Ni determination. During the infusion process, up to 85 % of Ni was extracted from tea leaves or flowers. Separation of Ni species was completed in 10 min by applying aqueous linear gradient elution with 0.6 mol L(-1) NH(4)NO(3). Ni was found to be present in the chromatographic fraction in which quinic acid was identified by Q-TOF in all the tea infusions analysed, which had pH values between 5.6 and 6.0. The only exception was the infusion of hibiscus tea with a pH of 2.7, where results of speciation analysis showed that Ni is present in its divalent ionic form.

The application of high-resolution gas chromatography–mass spectrometry and tandem mass spectrometry (MS–MS) in environmental analysis is demonstrated with three typical compound types, i.e., polychlorinated biphenyls (PCBs), polychlorinated alkanes (PCAs) and polychlorinated naphthalenes (PCNs), found in/or during the preparation of some environmental samples from a contaminated area. With ‘multiple reaction monitoring’ of some selected reaction products from a collision cell (i.e., loss of one or two chlorine radicals from a molecular ion) by the Q-analyser of a VG-AutospecQ mass spectrometer, unambiguous qualitative and quantitative data for various isomeric PCBs and PCNs could be obtained. By using this approach, time consuming and extremely demanding sample preparation could be reduced or avoided. In addition, the determination of trace amounts of higher chlorinated PCBs in paraffin oil illustrates the unique capability of MS–MS.

The use of a derivatization procedure for the measurement of aldoses by forming alditol acetates by strong acid hydrolysis is described. Quantitative data based on standard mixtures of neutral sugars were obtained by capillary gas chromatography and gas chromatography–mass spectrometry using phenyl-β-D-glucopyranoside as an internal standard. Tandem mass spectrometry was used for the structural elucidation of complex saccharide mixtures. In order to differentiate between alditol acetates, i.e., hexitols, pentitols and deoxyhexitols, the collision-activated reactions m/z 361→259, 303→201 and 217→115 were monitored by the Q sector of a VG-AutospecQ mass spectrometer. The method was applied to the study of the composition of polysaccharides in particulate organic matter and macroaggregates in the northern Adriatic Sea.

Ketoprofen (KP) is a nonsteroidal anti-inflammatory drug, which during UV irradiation rapidly transforms into benzophenone derivatives. Such transformation products may occur after topical application of KP, which is then exposed to sunlight resulting in a photo-allergic reaction. These reactions are mediated by the benzophenone moiety independently of the amount of allergen. The same reactions will also occur during wastewater or drinking water treatment albeit their effect in the aqueous environment is yet to be ascertained. In addition, only a few such transformation products have been recognised. To enable the detection and structural elucidation of the widest range of KP transformation products, this study applies complementary chromatographic and mass spectrometric techniques including gas chromatography coupled to single quadrupole or ion trap mass spectrometry and liquid chromatography hyphenated with quadrupole–time-of-flight mass spectrometry. Based on structural information gained in tandem and multiple MS experiments, and on highly accurate molecular mass measurements, chemical structures of 22 transformation products are proposed and used to construct an overall breakdown pathway. Among the identified transformation products all but two compounds retained the benzophenone moiety—a result, which raises important issues concerning the possible toxic synergistic effects of KP and its transformation products. These findings trigger further research into water treatment technologies that would limit their entrance into environmental or drinking waters. Copyright © 2011 John Wiley & Sons, Ltd.

Electron ionization (EI), chemical ionization and mass-analysed ion kinetic energy (MIKE) spectra have been applied with the aim of obtaining an unambiguous differentiation between the anomeric 2,3-O-isopropylidene α-and β-D-ribofuranosyl azide derivatives. The MIKE spectra of their metastable [M CH3]+ ions, originating from EI, showed a decomposition pattern allowing distinction between the anomers. The origin of the ions in the EI mass spectra, supported by examination of the deuterium-labelled derivatives, makes it possible to identify the actual azido group orientation in a particular anomer.

Guanine derivatives were examined using the tandem mass spectrometry (MS/MS) method. Isomeric structure differences were explored by means of the unimolecular decomposition spectra of the common ion m/z 151 having the empirical formula of the guanine molecular ion. An interconversion of the isomeric structures as the sample temperature is gradually raised, was observed.

Debaryomyces hansenii is a marine yeast that has to cope with different stress situations. Since changes in membrane properties can play an important function in adaptation, we have examined the fluidity and lipid composition of purified plasma membranes of D. hansenii grown at different external pH values and salt concentrations. Growth at low pH caused an increase in the sterol-to-phospholipid ratio and a decrease in fatty acid unsaturation which was reflected in decreased fluidity of the plasma membrane. High levels of NaCl increased the sterol-to-phospholipid ratio and fatty acid unsaturation, but did not significantly affect fluidity. The sterol-to-phospholipid ratios obtained in D. hansenii grown under any of these conditions were similar to the ratios that have been reported for halophilic/halotolerant black yeasts, but much smaller than those observed in the model yeast Saccharomyces cerevisiae.

A steady production of positive hydrated oxygen molecular ions has been achieved by the introduction of H2O vapour into the ion source of a mass spectrometer under chemical ionization conditions using O2 reagent gas. Collision-induced dissociation, mass-analyzed ion kinetic energy (CID MIKE) spectra (R. G. Cooks, J. H. Beynon, R. M. Caprioli and G. R. Lester, Metastable Ions, Elsevier, Amsterdam, 1973) of the m/z=50 ions, which correspond to the H2O·O ions, show a prominent loss of a water molecule, but no significant hydrogen loss. By contrast, the CID MIKE spectra of the H2O ions obtained under identical conditions indicate an important successive loss of hydrogen and oxygen atoms, giving rise to an intense H2O+· peak. Conversely, with H2O·O, a relatively loosely-bound adduct of the two stable moieties is indicated, a ‘cluster’ that fragments into its constituents with a preferential charge retention on the species of lower ionization energy.