ALBERT

Notes: A concentrate of whey protein (WPC) was prepared from cottage cheese whey by precipitation with sodium hexametaphosphate. Continuous fibers were spun by extruding a spinning solution into an acetic acid-sodium chloride coagulating bath Spinning solutions consisted of WPC and sodium dodecylbenzene sulfonate dissolved in water at pH 9.0 containing 0.5% Zmercaptoethanol. Residual detergent was extracted with aqueous acetone, and finished fibers were evaluated for diameter, tensile strength, elongation and rehydration properties. Stretching during formation reduced diameter and improved tensile strength. Single fibers and tows could be handled successfully and maintained their structural integrity during rehydration. Single-step extraction left less than 1% residual detergent.

Notes: Many recent modular design methods and approaches have focused on the modularization process - decomposition and composition. This paper suggests an integrated methodology that includes additional tools and stages for a complete modular architecture design. The borders of the modular design process are expanded by adding strategic issues, appropriateness to modularity, degree of modularity and modularity strategies, in an operationalized manner. The methodology presents a "requirements analysis- decomposition-composition-design evaluation" structure. The "modularization process" is designed so as to choose from three different perspectives - customer-based, function-based and structure-based design. To test and validate the methodology it was applied to a domestic gas detector product family. As a result, a new modular product architecture with eight modules was developed.

Notes: Abstract Transport of ammonium and methylamine into the cells of green sulfur bacterium Chlorobium limicola and purple sulfur bacterium Thiocapsa roseopersicina is carried out by a common transport system. This system has (for C. limicola and T. roseopersicina, respectively) pH optimum 7.0 and 7.5; Vmax 0.6 and 4.2 nmol min−1 (mg protein)−1; Km 5.9 × 10−5 M and 1.3 × 10−5 M, and is capable of forming 120- and 600-fold methylamine gradients. The methylamine transport can be energized by the artificially imposed transmembrane K+ diffusive potential and is inhibited by tetraphenylphosphonium or valinomycin and K+. The data presented indicate that methylamine transport in both studied species is exclusively driven by the membrane potential gradient (ΔΨ).

Notes: Abstract It was shown that glutamine synthetase of purple sulfur bacterium Thiocapsa roseopersicina is regulated by covalent modification. This conclusion is made on the basis of results showing that: (i) incubation of cells under conditions of nitrogen deprivation in the light lead to an increase of glutamine synthetase activity; (ii) addition of ammonium to nitrogen-starved cell suspensions caused a rapid decrease of glutamine synthetase activity; (iii) inhibition of glutamine synthetase by feedback modifiers was higher in ammonium-treated cells than in those starved for a nitrogen source; (iv) treatment of purified glutamine synthetase and cell-free extracts with phosphodiesterase was accompanied by an increase of glutamine synthetase activity, indicating the cleavage of modifying residues covalently bound to glutamine synthetase molecules.

Notes: Abstract  A rapid reversed-phase high performance liquid chromatographic analysis for the determination of seven aliphatic diamines in water is described. Precolumn derivatization with acetylacetone is used for traces of aliphatic diamines in water-methanol (10:1 v/v) medium. The acetylacetone derivatives obtained after 15 min were extracted with an octadecylsilane functionalized silica cartridge, and then injected into the HPLC system. The HPLC system consisted of a reversed-phase column, and a spectrophotometric detector adjusted to 310 nm as elution solvent a methanol-tetrahydrofuran-water (55:3:42 v/v) mixture was used. The acetylacetone derivatives of the C2-C7 diamines were separated with a good resolution in 23 min. The detection limits achieved for each diamine were between 0.18–0.72 ng/ml for a 100 ml water sample. The recovery of diamine derivatives from river and seawater was 88–101%, with relative standard deviations of 2.2–4.0%, and 82–93%, with relative standard deviations of 2.8–4.6%, respectively. Aliphatic diamines are widely used as chemical reagents, occur as metabolic in biomedical studies and are used as chelating agents in analytical chemistry. As they are soluble in water, their use results in their ultimate release to the environment. The need for a sensitive, selective and rapid determination of aliphatic diamines in environmental samples thus has become important. Dobberpuhl et al. [1] have described a highly sensitive pulsed electrochemical detection for aliphatic monoamines and diamines following their chromatographic separation. Although, it is a sensitive method the determination has to be carried out in alkaline conditions. The most common method for the determination of aliphatic amines is high performance liquid chromatography (HPLC), using different derivatives with either fluorescence [2–5] or UV-visible detection [6–11]. The fluorescence detection method most often relies on post-column derivatization, which requires a second pump to deliver the reagent. Acetylacetone is soluble to some degree in water, and has been used as a pre-column derivatization reagent [12]. The reaction only is effective with diamines, and results in UV-active acetylacetone derivatives known as Schiff bases. But acetylacetone requires a long reaction time in water, which makes it rather unsuitable for routine analysis. In this paper an optimized reversed-phase HPLC determination procedure for C2-C7 aliphatic diamines at low ng/ml levels in water is described.

Notes: Abstract Immunodetection of catecholamine biosynthetic enzymes is frequently used for the visualization of central nervous catecholaminergic systems. Because of the method's limited specificity for the different catecholamines, interpretation of the results often presents difficulties. To determine criteria for the identification of dopaminergic, noradrenergic, and adrenergic afferents to the rat amygdaloid complex, comparative immunolabelling for tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DBH), and phenylethanolamine-n-methyltransferase (PNMT) was carried out using single- and double-labelling for fluorescence, light- and electron microscopy. The observations were complemented by findings in brainstem and hypothalamic areas. The results indicated that. TH-labelling detected preferentially dopaminergic afferents in the lateral central and intercalated amygdaloid nuclei. DBH-labelling detected noradrenergic axons in nuclei lacking PNMT-immunoreactive fibres, and PNMT was a marker for adrenergic axons in the entire complex. For nuclei with combined dense dopaminergic, noradrenergic and/or adrenergic innervation, morphological and immunolabelling characteristics were described which, to a certain extent, enabled identification of the different afferents in anti-TH or anti-DBH-preparations. Using a monoclonal TH-antiserum, noradrenergic and adrenergic axons displayed weaker immunoreactivity than dopaminergic ones, and possessed characteristic morphological features. TH-immunoreactivity in noradrenergic axons differed depending on their origin, and showed intra-axonal compartmentalization. The present study provides a basis for the use of the detection of biosynthetic enzymes in future investigations into the ultrastructure and connectivity of the catecholaminergic amygdala innervation.

Notes: Abstract In situ hybridization (ISH) of somatostatin (SOM) mRNA was carried out on sections of rat brain using an alkaline phosphatase (AP) coupled oligonucleotide probe. Different hybridization and AP development conditions were tested for qualitative and quantitative detection of target mRNA on sections of unfixed tissue. Hybridization signal intensities after 24 h of hybridization were high. Comparison with adjacent formaldehydefixed tissue sections and hybridization for various lengths of time (2–42 h) indicated that in unfixed tissue retention of SOM mRNA was at least as high as after fixation, and that the mRNA was not degraded during hybridization. The use of tetranitroblue instead of nitroblue tetrazolium chloride in the AP detection medium provided a superior signal-to-noise ratio, and medium stability was improved for quantitative studies on unfixed sections by adding 10% polyvinyl alcohol at pH 8.5. Microphotometric measurements of mean optical densities (MOD) of the formazan reaction product in a defined area within individual neurons of the lateral central amygdaloid nucleus showed a linear increase over the first 23 h of AP reaction time. The mean MOD values per neuron were comparably high in various equally thick sections of the nucleus and increased with section thickness in a linear manner. The findings indicate that the ISH and detection reagents penetrate the entire section and that there is a linear relationship between the amount of AP reaction product measured and the amount of mRNA present in the measured area. Thus, ISH using an AP-coupled oligonucleotide on sections of unfixed tissue appears suitable for quantitative mRNA detection.