Degradability of selected azo dye metabolites in activated sludge systems.

The stability of eight environmentally relevant azo dye metabolites [o-aminotoluene (2), 4,4'-thiodianiline (4), 4,4'-diaminodiphenylmethane (6), p-chloroaniline (7), 2,4-toluylenediamine (9), p-kresidine (14), 2,4-diaminoanisole (15), and 2-naphthylamine (18)] was investigated in activated sludge systems and compared to their hydrolysis stability. For both studies, test systems of the EC and EPA were used. The results show that degradation under aerobic conditions proceeds via oxidation of the substituents located on the aromatic ring or on the side chain. Under anaerobic conditions, the azo bond is reductively cleaved, which leads to the substituted amines. These are toxic and potentially hazardous to the environment.

Multidimensional gas chromatographic enantiomer quantification of some chlorinated xenobiotics in cod liver and fish oils.

Four chiral HRGC column systems for the separation of selected organochlor pesticides and photoconversion products (heptachlor, cis- and trans-chlordane, o,p'-DDT, o,p'-DDD, and alpha-HCH) were tested. Cod hver oil and fish oil samples from different countries were comparatively analyzed. Of all these columns, the fourth was the most suitable one for the analysis of the selected compounds. The enantiomer ratios [ER] of cis-chlordane, trans-chlordane, photodieldrin, alpha-HCH, and o,p'-DDD in fish oils are nearly 1.0, while the ERs of the same substances are significantly different from 1.0 in cod liver oils. Contrary to that, the ER values of o,p'-DDT are remarkable different from 1 in the cod liver oils as well as in the fish oils.

Decoration and shadowing of freeze-etched catalase crystals.

Aqueous suspensions of catalase crystals were freeze-cleaved, deep-etched and either shadowed with Ta/W at 45 degrees or decorated with 0.1-0.9 nm thick deposits of Au and Pt at normal incidence. The electron micrographs of the decorated specimens were processed by correlation averaging and compared with a relief reconstruction obtained from shadowed specimens. Pronounced decoration was observed on the catalase crystals at temperatures between 130 and 180 K. Disregarding the difficulties in interpretation, the averages of 0.1-0.2 nm thick Au and Pt films reveal more structural detail than the relief reconstruction. Perfect shadowing provides information on surface topography and is relatively easy to comprehend; decoration renders variations in physico-chemical affinity visible. Problems of the interference of decoration and shadowing effects in the intuitive interpretation of freeze-etch replicas and in relief reconstruction are discussed as well as the disturbing effects of a non-ideal carbon backing. The perspectives of using decoration intentionally as a positive staining technique for the investigation of frozen-hydrated surfaces are evaluated and quality criteria are defined.

Studies on Scenedesmus acutus growth. I effect of autotrophic and mixotrophic conditions on the growth of Scenedesmus acutus.

Among sugars, glucose and mannose were found to be the most suitable substrates for mixotrophic growth, uptake of galactose and its influence on growth was negligible, and sucrose and fructose occupied intermediary positions. The optimum temperature for sugar uptake was 30 degrees C, both under light and in darkness. Enhancement in the photosynthetic oxygen-evolution rate, based on the utilization of substrates, was foremost in the presence of glucose, followed by mannose, sucrose, and fructose. Industrial by-products such as sugarcane molasses also were utilized to increase the algal growth under mixotrophic conditions. A maximum yield in biomass was obtained subsequent to the combined supply of sugarcane molasses with carbon dioxide to indoor as well as outdoor mixotrophic cultures. Doubling the carbon dioxide supply alone above a certain level, under autotrophic and mixotrophic outdoor conditions, did not produce a pronounced increase in the algal growth rate. The results on autotrophic and mixotrophic growth variations are discussed in the article.

Studies on Scenedesmus acutus growth II. Effect of autotrophic and mixotrophic growth on the amino acid and the carbohydrate composition of Scenedesmus acutus.

As a general rule an increase in carbohydrates occurs during the light phase of the cell cycle and that of protein during phase, although variations were found in these components under autotrophic and mixotrophic growth conditions. The results are based on the quantitative determination of carvohydrates as trimethylsilyl (TMS) derivatives and amino acids as N-trifluoroacetyl-n-butyl (TAB) esters in algal cells cultured in light and dark periods by gas-liquid chromatography (LC). Cells harvested during the dark period contained more amino acids as compared to similar cultures harvested during the light phase. In light, the production of amino acids of the aspartate family increased in cells cultivated with glucose and carbon dioxide. With glucose as sole carbon source, the carbohydrate content was higher in the dark than in the light period. Under continuous light conditions, in the presence of carbon dioxide, there was a decrease in the carbohydrate content also. Gas-liquid chromatography analysis of the extract of the purified cell walls showed that they are made up of 0.076% carbohydrates and 0.28% amino acids on the dry weight (DW) basis of whole cells. The results on the metabolism of cells, under autotrophic and mixotrophic conditions, are discussed in this article.

Studies on Scenedesmus acutus growth. The incorporation of 14C-glucose by Scenedesmus acutus under light and dark periods.

Qualitative and quantitative estimations of alcohol-extractable compounds from (14)C-glucose-incorporated Scendesmus acutus cells were performed at various intervals of time. After two hours of incubation with (14)C-glucose in light, amino acids were synthesized at 65% and sucrose at 26% of the total input label. In the dark incorporation, 30% of the total radioactivity was found in amino acids and 46% in sucrose. Leucine and valine were detected only during the oxidation of glucose in light. The concentration of serine increased more in the presence of light, as compared to dark. These results on the oxidation of glucose are discussed in this article.

[Gaschromatographic determination of ingredients in fermentated beverages v. quantitative gaschromatographic determination of anthocyanes and anthocyanides in red wine (author's transl)]. / Gaschromatographische Bestimmung der Inhaltsstoffe von Gärungsgetränken V. Quantitative gaschromatographische Bestimmung von Anthocyanen und Anthocyanidinen als TMS-Derivate in Rotweinen

After special preparation of several red wines, anthocyanidines like pelargonidine, delphinidine, cyanidine, paeonidine, malvidine and petunidine as well as their 3,5-glucosides have been determined quantitatively with high accuracy by gas chromatography.

[Biosynthesis of aroma compounds by microorganisms II. Formation of sulphur containing flavour substances from methionine by Saccharomyces cerevisiae (author's transl)]. / Uber die Biosynthese von Aromastoffen durch Mikroorganismen II. Bildung von Schwefelverbindungen aus Methionin durch Saccharomyces cerebisiae

Using methionine as single nitrogen source 3-(methylthio)-1-propanol, 3-(methylthio)-propanal, 3-(methylthio)-propylacetate and 2-methylthiophan-3-one were formed in anaerobic model fermentations by Saccharomyces cerebisiae. The sulphur compounds were enriched by liquid-liquid extraction and detected by a selective flame photometric detector (FPD). The identities of the components were confirmed by mass spectrometry. It could be shown by quantitative determiniations that methionine was metabolized with 56--61% to 3-(methylthio)=1-propanol, when it was given to the medium in concentrations from 10 to 100 mg/1. 3-(methylthio)-propylacetuate, 3-(methylthio)-propanal, and 2-methylthiophan-3-one only could be detected in traces.

[GLC-mass-spectrometrical investigation of the volatile components of wines vii. Aroma compounds of tokaj aszu wines b) organic acids (author's transl)]. / Gaschromatographisch-massenspektrometrische Untersuchung flüchtiger Inhaltsstoffe des Weines VII. Aromastoffe in Tokajer Weinen b) Organische Säuren

An inventory of the organic acids detectable by liquid-liquid extraction has been made in different Tokaj wines. After the separation of the acidic compounds in the aroma extracts using Na2CO3 and after the derivatization with diazomethane 65 methylester have been separated by gaschromatography and identified by mass spectrometry. Using a special fractionation method organic acids, amino acids, carbohydrates and phenolic compounds have been isolated in different groups. After the derivatization of the components 50 organic acids have been quantitatively determined by gaschromatography. The compositions of the acids in the wines differ considerably. The quantitative differences are caused by the vintages, the method of production and the kind of storage. The possible biosynthetic pathways of the various acids are discussed.