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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 21 (1978), S. 131-137 
    ISSN: 1573-4919
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Alpha D-mannosidase activity in goat semen was observed to be distributed in sperm and seminal plasma. In sperm the enzyme, present in soluble and bound forms, was located within the acrosome. The bound enzyme was associated with the denuded sperm. Seminal plasma α-mannosidase was purified 100-fold and the final preparation was shown to be homogeneous by polyacrylamide and SDS gel electrophoresis and on isoelectric focusing. The molecular weight of the enzyme, determined by gel filtration and disc electrophoresis in the presence of SDS, was 220,000. The isoelectric pH was 7.42 and the amino acid composition is reported. α-Mannosidase catalyzed the hydrolysis of both synthetic and natural substrates. The Km of p-nitrophenyl α-D-mannoside and α-methyl D-mannoside were 0.695 mm and 71.9 mm at pH 4.0, the optimum pH. The natural substrates were hydrolysed to varying degrees. Zn2+ was not essential though it activated the enzyme activity over longer incubations. The enzyme was observed to be more stable at wider pH range in the presence of Zn2+ than in its absence. EDTA which did not affect the enzyme activity has effect on enzyme stability similar to Zn.2+ Seminal α-mannosidase is not a zinc metalloenzyme but is activated by Zn2+.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 57 (1978), S. 99-101 
    ISSN: 1573-5117
    Keywords: Karyotype-Nitella ; cytotaxonomy of charophyta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The new chromosome number n = 9 has been reported in Nitella mirabilis Nordst. ex. Groves em. R.D.W. Discussing the significance of this new chromosome number with regard to arthrodactylous and anarthrodactylous groups of the genus Nitella, the possible origin of a 9 chromosome form of N. mirabilis due to hybridization has been suggested.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 14 (1979), S. 1631-1640 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract High-strength low-alloy (HSLA) steels having low impact transition temperature are possible substitutes for costlier 2 1/2% and 3 1/2% nickel steels. The effects of solid solution strengthening, grain size and precipitation in ferrite on the strength and toughness of low-carbon steels and the special advantages of vanadium as an alloying element in HSLA steels, are discussed. An investigation has been carried out with 1.5% manganese low-carbon steels containing vanadium in the range 0.12% to 0.29% and 0.013% to 0.017% nitrogen. Room temperature tensile and sub-zero temperature impact tests down to−100° C, and a metallographic study to determine the grain sizes and pearlite contents of the steels normalized at different temperatures, have been carried out. Calculations are made with empirical equations for yield and tensile strengths and the values obtained are compared with those experimentally observed. The solubility products of vanadium carbide and vanadium nitride are calculated and compared with available data to throw light on the mechanism of strengthening of the steels.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 123 (1975), S. 255-262 
    ISSN: 1615-6110
    Keywords: Malvaceae ; Abelmoschus esculentus ; Embryo ; endosperm ; seed development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The endosperm is nuclear, cell wall initiation starts 5 days after pollination. During early stages endosperm nuclei exhibit synchrony in their division. Embryogeny is of the Asterad type. A7-to 10-celled suspensor persists up to the dicot stage of the embryo. Both integuments contribute towards formation of the seed coat. 30 days after pollination seeds become mature. Their endosperm is scanty and persists as a thin layer between the folds of the cotyledons. Nucellus remnants are present towards the funicular side.
    Type of Medium: Electronic Resource
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