Fish quality assessment with ion mobility based gas detector.

Measurement of the mixture of extractable volatile compounds of the gills of vendace was used in the fish freshness evaluation (Coregonus albula L.). MGD-1 gas detector was used for the detection of volatile compound profiles of hexane extracts of gills. The measuring principle of MGD-1 is ion mobility distribution and is based on IMCELL technique. A 2.5 microl sample of hexane extract was heated on a ceramic plate and the vapour was carried with a constant flow (2.5 I/min) of active carbon filtered air to the detector. The ion mobility distribution spectrum was measured every 1 second for 2 minutes. For reference, the microbial counts of gills, ATP-breakdown products (K-value) of fish flesh, electrical properties (Torrymeter scores) of fish skin and sensory evaluation scores were measured. The ion mobility distribution profiles of gills changed significantly during the 7 days storage period The findings related to freshness evaluation were supported by the reference methods. There is, however, a seasonal difference in the freshness probably due to seasonal variation of microbial flora. Besides the evaluation of fish quality, ion mobility distribution based technique provides a new analytical tool for food quality assessment.

Monitoring odorous sulfur emissions using self-organizing maps for handling ion mobility spectrometry data.

Possibilities for monitoring emissions of reduced sulfur compounds in pulp and paper mills were investigated using ion mobility spectrometry (IMS) and a self-organizing map (SOM) algorithm. The reduced sulfur compounds measured were hydrogen sulfide (H2S), dimethyl sulfide (DMS), and methyl mercaptan (MM). Attention was paid to momentary concentrations because there is no monitoring device able to measure peak concentrations of reduced sulfur compounds under field conditions. These methods were evaluated by measuring the reduced sulfur compounds first in the laboratory and then at a process monitoring site at a pulp factory. The aim was to find out whether it would be possible to use the laboratory measurements to recognize the same reduced sulfur compounds at the monitoring site. Data collection was followed by analysis using the SOM algorithm and Sammon's mapping. The results showed that the IMS spectra of reduced sulfur compounds and their mixtures can be distinguished from each other by computationally intelligent methods and that the spectra from the process monitoring site corresponded with the laboratory measurements to a certain extent.

Directly acting geno- and cytotoxic agents from a wild mushroom Dermocybe sanguinea.

The wild mushroom, Dermocybe sanguinea, contains several anthraquinone pigments, of which emodin (1,3,8-trihydroxy-6-methylanthraquinone) is quantitatively the most important. In our preliminary tests, Dermocybe sanguinea extracts were genotoxic without metabolic activation. The ethanol extract of Dermocybe sanguinea was fractionated by flash chromatography, and the emodin contents of the fractions were determined by HPLC. Their genotoxicities were assayed using a bacterial repair assay and sister-chromatid exchange analysis. The cytotoxicity of the fractions was assayed with mouse hepatoma cells using growth inhibition as the endpoint. The results of the biological tests were compared with those obtained with pure emodin. It was concluded that, in addition to emodin, Dermocybe sanguinea contains several other geno- and cytotoxic compounds.

An electron microscope study of resin production and secretion by the glands of seedlings of Betula pendula Roth.

Transmission and scanning electron microscopy were used to study the ultrastructure and secretory processes of resin glands on shoot stems of Betula pendula seedlings during seasonal growth. The multicellular peltate glands possess a cortex of columnar cells surrounding a parenchymal medulla differing from the stem parenchyma below. Myelin-like deposits comprising concentric layers of membranes and osmiophilic substances accumulate mainly in the cortical cells, while only the medullar cells have chloroplasts. Both of these deposits appear to be synthesized, initially, in the endoplasmic reticulum. The myelin-like material is believed to consist of steroidal triterpenoids in cytoplasmic membranes, and the osmiophilic deposits to represent phenolics. Studies of glands of different ages suggest that the electron-transparent resin ultimately exported is formed by combining the two initial products. In the cortical cells the secretion first accumulates in vesicles that fuse with larger ones and the periplasmatic space. From the latter the secretion diffuses through the cell wall and the resin is finally deposited in the subcuticular space. Secretion vesicles, but no periplasmatic deposits were seen in the medullar cells. At the end of seasonal growth the cortical cells are markedly vacuolate and appear to have lost their organelles. Some of the cells accumulate an electron-opaque material not seen earlier. The medullar cells of the glands are suberized before winter dormancy, but usually later than in the surrounding stem bark.

Identification of aromatic moieties and mycosamine in antifungal heptaenes with high-performance liquid chromatography, high-performance liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry.

A high-performance liquid chromatographic (HPLC) method for the determination of the aromaticity of heptaene polyene antibiotics has been developed. The released aromatic moiety of the heptaene polyenes aureofungin, candicidin, candimycin, hamycin and trichomycin was assayed after alkaline hydrolysis. The presence of p-aminoacetophenone (PAAP) and N-methyl-p-aminoacetophenone (N-methyl-PAAP) in the hydrolysates was determined by HPLC, HPLC-mass spectrometry (HPLC-MS) and gas chromatography-MS (GC-MS). Candicidin and hamycin contained only the PAAP residue; aureofungin contained both PAAP and N-methyl-PAAP. Trichomycin contained PAAP and also some unknown component of molecular weight 179. The aromatic nature of the individual components of the heptaene complex was demonstrated using radioactivity flow detection for the determination of the incorporation of [14C]-p-aminobenzoic acid to individual candicidin components. Ammonia chemical ionization MS was successfully used for the GC-MS identification of the acetylated mycosamine moiety of heptaenes.

Polyene antibiotics increase the ionic permeability of synaptosomal plasma membranes.

The effects of antifungal heptaene antibiotics candicidin and amphotericin B were investigated in isolated cerebral cortical nerve terminals (synaptosomes). The synaptosomes were incubated with candicidin or amphotericin B in the presence or absence of external Ca2+. Candicidin (0.4-0.8 I.U./mL) increased intrasynaptosomal free Ca2+ significantly. This increase was not significantly suppressed by 30 microM verapamil or 2 microM nifedipine. In the absence of extrasynaptosomal Ca2+ intrasynaptosomal free Ca2+ was not changed by candicidin. Amphotericin B increased intrasynaptosomal free Ca2+ as well. Candicidin (0.05-0.6 I.U./mL) increased the respiration rate up to 3.5-fold above the basal rate. This response was not affected by the absence of extracellular Ca2+. Ouabain completely blocked the increase of respiration caused by candicidin, whereas tetrodotoxin was ineffective. The plasma membrane depolarized in a dose-dependent manner after candicidin (0.2-0.8 I.U./mL). The mitochondrial membrane potential was little affected and only at the highest concentrations. The results indicate that heptaene polyenes increase synaptosomal ionic permeability, which is reflected in increased Ca2(+)-influx and accelerated respiration. The increment in synaptosomal free calcium takes place probably as a nonspecific leak via typical polyene-cholesterol channels. The respiration is accelerated by increased Na(+)-permeability through the plasma membrane which stimulates the function of Na+, K(+)-ATPase and thus increases the energy demand.

Calcium-dependent histidine and histamine release from superfused synaptosomes.

The release of radioactive histidine and histamine was studied in a superfusion system by using guinea pig synaptosomes which were preloaded with 3H-histidine. Depolarization by 50 mM K+ induced a simultaneous release of histidine and histamine. The stimulated release of both of these substances was diminished when calcium was removed. The calcium-dependency of histamine release, previously demonstrated in brain slices, was confirmed using synaptosomes. It was also demonstrated that potassium-induced histidine release from guinea pig synaptosomes under superfusion conditions is at least partially calcium-dependent.

Histidine release from brain slices and synaptosomes.

The release of radioactive histidine was studied in a superfusion system by using preloaded rat cerebral cortical slices and guinea pig synaptosomes. ATP/ADP ratios in both preparations were used to assess the energy levels and thus the oxygenation of brain slices and synaptosomes. ATP/ADP ratios similar to the intact brain and nerve terminals were found in slices and synaptosomes even after hours of superfusion with oxygenated buffer. Depolarization by 30 or 50 mM K+ induced release of histidine from slices and synaptosomes. The results confirm that under physiological energetic conditions, histidine is released both from slices and synaptosomes after depolarization with potassium.

Pharmacokinetics and acute side-effects of nifedipine given as slow-release tablets or liquid-filled capsules.

The pharmacokinetics and acute adverse effects of nifedipine were studied in a cross-over, single dose (20 mg) study on ten healthy young volunteers. From the liquid-filled capsules, nifedipine was absorbed rapidly (tmax at 30-40 min). From tablets, the peak concentration was 79-88% lower and occurred 74-133 min after ingestion; also the bioavailability was lower, as indicated by on average 39% lower area under curve values after tablets. All the volunteers experienced side-effects: the most common (nine out of the ten) and the most intense was headache. One volunteer withdrew because of unbearable vomiting and headache. Also others felt nauseous (six out of nine who continued) and four of them vomited. After tablets, the dizziness was markedly less than after capsules, but the more slowly-appearing symptoms such as headache and nausea were similar after both types of drug products. By using slow-release tablets instead of capsules it seems possible to avoid some side-effects of nifedipine, but this benefit is gained at the expense of bioavailability.

Ethanol and liver protein synthesis in vivo.

Ethanol was administered i.p. to adult roosters during hormonally induced vitellogenin synthesis. At moderate doses, ethanol had no influence on the synthesis of vitellogenin nor did it cause alterations in the size distribution of liver polyribosomes.