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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 123 (1979), S. 23-35 
    ISSN: 1432-072X
    Keywords: Yeast ; Compartmentation ; Vacuoles ; Lysosome ; Cytosol ; ATPase ; Phosphatases ; Proteases ; Polyphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Almost all the vacuoles (about 95%) remained intact after “polybase-induced lysis” of the yeast protoplasts. These vacuoles could be sedimentated together with other cell organelles which were equally well preserved, leaving as a supernatant a cytosol fraction which was essentially uncontaminated by the contents of disrupted vacuoles. After density gradient centrifugation more than half of the vacuoles were recovered in a fraction which was highly purified as judged from the measurement of several marker enzymes and from light and electron microscopic observations. Polyphosphate, which has been shown to be located exclusively in the vacuolar sap of protoplasts, was used as a vacuolar marker to determine the yields of vacuoles in the different fractions obtained from the density gradients. It was also used to assess the overall distribution of lytic enzymes in the cytosol and in the vacuome. The results indicate that the following enzyme activities are mostly, if not exclusively (〉90%), located in the vacuome, probably all in the typical large vacuoles present in the protoplasts: exo-and endopolyphosphatase, proteases A and B, carboxypeptidase Y, an aminopeptidase, RNase, α-mannosidase, and phosphatases which hydrolyze a number of different substrates. The polyphosphatases are thus in the same compartment as the polyphosphate. The activities of some other hydrolases, notably of a Mg2+ dependent, Oligomycin and NaN3 insensitive ATPase and alkaline phosphatase, were partially associated with the vacuoles. The activities of pyrophosphatase, tripolyphosphatase, α-glucosidase, and aminopeptidase active in the presence of EDTA, were located almost exclusively in the soluble, cytosolic fraction.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 60 (1974), S. 1378-1383 
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0014-5793
    Keywords: Cytosol ; Lysosome ; Trehalase ; Vacuole ; Yeast ; cAMP
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-0867
    Keywords: calcium ; compost ; irradiation ; magnesium ; manure ; sewage sludge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Application of organic waste influences crop uptake of Ca and Mg and soil extractability, depending on the nature of the crop and the waste. Four organic wastes: (i) digested sewage sludge (DSS), (ii) irradiated sludge (DISS), (iii) composted sludge (DICSS), and (iv) composted livestock manure (CLM) were applied for two years at rates of 10, 20, 30, and 40 Mg solid ha-1 year-1. Fertilizers N and K were applied to the control treatment (CT), as well as to the waste treatments to supplement crop growth across all treatments, so that these nutrients were not treatment variables. Calcium and Mg concentrations in the tissue of lettuce, bean pods and petunias in 1990 and two cuts of lettuce in 1991, and the CH3COONH4-extractable soil Ca and Mg were determined. Concentration of Ca and Mg in bean pods did not change to the waste application. Calcium concentration in bean pods was less than half of that in other crops. Magnesium concentration in bean pods and petunias was same, but was much lower than in lettuce. Application of DSS, in general, increased Ca concentration in the crops more than did other wastes. The extractable soil Ca was positively correlated with Ca applied with DISS (r=0.453, P〈0.05). Although only a limited amount of Ca was supplied with CLM at the rate of 10 Mg solid ha-1(40 kg Ca ha-1), Ca concentration in petunias increased significantly, then, decreased with increased Ca application (r=0.453, P〈0.05). A similar pattern with CLM was found in the extractable soil Ca. The waste application from all the sources had no influence on crop Mg concentration in 1990, possibly due to low Mg concentration in the wastes. While continuously applied DSS and DISS in 1991 linearly increased Mg concentration in both cuts of lettuce (r=0.867, P〈0.01; r=0.670, P〈0.01 and r=0.671, P〈0.01; r=0.665, P〈0.01 for first cut and second cut of lettuce with DSS and DISS application respectively), application of CLM decreased Mg concentration in first cut lettuce. The patterns of extractable soil Mg were opposite to crop Mg concentration, as the extractable soil Mg linearly increased with CLM, and decreased with the high rate of DSS application. The ability of wastes to supply N was an important factor influencing crop Σ cations (K, Ca and Mg) uptake.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 48 (1965), S. 28-46 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stability constants of the methylmercury complexes CH3HgL1-λ with a considerable number of ligands Lλ- have been determined (Table 1). Like H+, the cation CH3Hg+ reveals the coordination number 1 almost exclusively. Some ligands form also binuclear adducts (CH3Hg)2L2-λ and sulfide even forms (CH3Hg)3S+. The coordination behaviours of CH3Hg+ and H+ however are very different concerning the selection of ligands, the former being a soft and the latter a hard acid in the sense of PEARSON. The entropy ΔS of the reaction: H+ + L- → HL is more positive by about 14 c.u. than ΔS of the reaction: CH3HG+ + L- → CH3HgL. The hydrogen ion in aqueous solution has a far greater order producing action on the solvent than CH3Hg+. Two dyes also have investigated, which may serve as indicators for CH3HG+ and for the determination of pCH3Hg (= -log[CH3Hg+]).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the reduction of substituted azobenzenes by dihydroquinoxalines have been measured. Azo-compounds with electron-donating substituents in o- or p-position are reduced to the amines in neutral or acid solution, whereby two molecules of the reducing agent are consumed. If such substituents are absent, the reaction stops at the hydrazo stage. This is also the case with cleaveable azo-compounds in strongly alcaline solution.Our kinetic measurements of the reductive cleavage reaction of methylorange are in agreement with only one mechanism, which is discussed in detail. The very high reactivity of protonated methylorange may be attributed to the formation of a mesomeric quinoid structure. Knowing the pH-dependence of the reaction rate allows the determination of the pK-value of the extremely unstable hydrazo stage of methylorange. The structure of the dihydroquinoxaline has a strong influence on ΔH
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 53 (1970), S. 1151-1168 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The primary product of the two step reduction of 2-phenylquinoxaline is the 1,4-dihydrocompound which undergoes a tautomeric rearrangement to the thermodynamically more stable 1,2-dihydro-3-phenylquinoxaline. The 1,4-dihydro compound is an extremely reactive reducing agent whereas the 1,2-dihydro form is almost inert against oxidizing agents. Both dihydro forms are in a kinetically hindered equilibrium. The rearrangement requires a transfer of a proton from a nitrogen to a carbon atom and is therefore relatively slow even at pH 0.The 1,2-dihydro compound cannot take part in redox reactions directly. If this compound is oxidized, the rate determining step is always the reversed tautomeric rearrangement.The effect of the kinetics of the tautomeric rearrangement on the polarographic behavior of the 2-phenylquinoxaline system is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 45 (1962), S. 775-783 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From a solution containing a mercury(II)salt and thiocyanate (ratio of about 1:4), a solution of a cobalt(II) salt precipitates, in presence of benzene, a bright pink mikrocrystalline compound of the exact composition: {CoHg2(SCN)6, C6H6}, which can be also obtained in well developed cristals. Reflexion and IR. Spectra show that CoII is octahedrally coordinated and that all six thiocyanate groups serve to bridge the two metal atoms: Hg…SCN…Co. It is suggested that the molecule of benzene formes π-bonds simultaneously with two mercury atoms, being the fourth ligand of each Hg2+. Benzene can be replaced by toluene, the three xylenes, naphthalene, anthracene, but not by aliphatic cyclic hydrocarbons. CoII can be replaced by octahedral NiII and CdII, but not by ZnII and CuII. The compounds are thermodynamically unstable. At about 100°C the cobalt-benzene compound loses the hydrocarbon rapidly and the colour of the solid residue turns from pink to a brilliant blue, due to the formation of a 1:1 mixture of {CoHg(SCN)4} and {Hg(SCN)2}. The compound {CoHg2(SCN)6} is non-existent, and it is unlikely therefore that it can serve as a host-lattice for benzene in a clathrate.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 53 (1970), S. 1169-1173 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reversible redox reactions which are followed by irreversible steps give often polarographic waves with drop life dependent shapes. A mathematical model is proposed which is capable to describe the change of the polarographic waves of quinoxalines, even at short drop lives and slow reactions of the irreversible step.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 54 (1971), S. 2431-2447 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The experimental results of our earlier investigation of the azodye bleach mechanism are interpreted in a revised manner. The reductive cleavage of methylorange by a dihydroquinoxaline proceeds in two steps. In the medium pH-range the first step (production of the hydrazo derivative) is slower (and not faster, as considered before) than the second (reductive splitting of the hydrazo derivative). In strongly acid solution this relation is reversed.The rate of disproportionation of the hydrazo derivative of methylorange is proportional to the concentration of the protonated hydrazo compound. For this reaction a two step mechanism is proposed in which a molecule of hydrazo compound is cleaved in a rate determining first step to an oxidizing particle and an amine molecule. In the following fast reaction the oxidizing intermediate attacks a second hydrazo molecule yielding methylorange and a further amine molecule. Based on this reaction sequence an azodye bleach mechanism is formulated which is able to explain the kinetics of the reductive cleavage of methylorange by a 1, 4-dihydroquinoxaline at any pH value.The azodye bleach mechanism is much more complex if the 1,4-dihydroquinoxaline used is able to form a radical or to tautomerize. The resulting reaction kinetics are discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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