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  • 1995-1999  (3)
  • 1985-1989
  • Cyclodextrinase  (2)
  • Acetylcholinesterase  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Metabolism of cyclodextrins byKlebsiella oxytoca M5a1: purification and characterisation of a cytoplasmically located cyclodextrinase (1996)
    Springer
    Archives of microbiology 165 (1996), S. 206-212 
    Details
    ISSN: 1432-072X
    Keywords: Cyclodextrin metabolism ; Klebsiella oxytoca ; Cyclodextrinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It has been shown previously that the products of 11 genes are required for metabolism of starch byKlebsiella oxytoca via a novel pathway. An extracellular cyclodextrin glucanotransferase first degrades starch into α-and β-cyclodextrins; evidence then has been presented that the cyclodextrins are transported into the cytoplasma via a specific system and that they are metabolised inside the cell. To provide support for this model, we have analysed whetherKlebsiella oxytoca possesses a cytoplasmic enzyme able to linearise cyclodextrins. A possible candidate was the product of thecymH gene since it displays sequence similarity with cyclodextrinases from other organisms. ThecymH gene was overexpressed, and the CymH protein was purified. CymH is a monomer of 69 kDa molecular mass and hydrolysed cyclodextrins at an optimum pH of 7.0 and an optimum temperature of 23° C, respectively. The apparentK m increased with increasing size of the cyclodextrins, but the reaction velocity decreased. Linear malto-oligosaccharides were also accepted as substrates, but were hydrolysed with a lower efficiency. Final products in each case were maltose and maltotriose. It was demonstrated by immunoblotting that CymH is located in the cytoplasm and that no signal peptide was cleaved off. SincecymH mutants were no longer able to grow on cyclodextrins, these results prove that cyclodextrins are degraded inside the cell, and they support the contention of the existence of a specific transport system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01692863
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Metabolism of cyclodextrins by Klebsiella oxytoca M5a1: purification and characterisation of a cytoplasmically located cyclodextrinase (1996)
    Springer
    Archives of microbiology 165 (1996), S. 206-212 
    Details
    ISSN: 1432-072X
    Keywords: Key words Cyclodextrin metabolism ; Klebsiella ; oxytoca ; Cyclodextrinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It has been shown previously that the products of 11 genes are required for metabolism of starch by Klebsiella oxytoca via a novel pathway. An extracellular cyclodextrin glucanotransferase first degrades starch into α- and β-cyclodextrins; evidence then has been presented that the cyclodextrins are transported into the cytoplasma via a specific system and that they are metabolised inside the cell. To provide support for this model, we have analysed whether Klebsiella oxytoca possesses a cytoplasmic enzyme able to linearise cyclodextrins. A possible candidate was the product of the cymH gene since it displays sequence similarity with cyclodextrinases from other organisms. The cymH gene was overexpressed, and the CymH protein was purified. CymH is a monomer of 69 kDa molecular mass and hydrolysed cyclodextrins at an optimum pH of 7.0 and an optimum temperature of 23° C, respectively. The apparent K m increased with increasing size of the cyclodextrins, but the reaction velocity decreased. Linear malto-oligosaccharides were also accepted as substrates, but were hydrolysed with a lower efficiency. Final products in each case were maltose and maltotriose. It was demonstrated by immunoblotting that CymH is located in the cytoplasm and that no signal peptide was cleaved off. Since cymH mutants were no longer able to grow on cyclodextrins, these results prove that cyclodextrins are degraded inside the cell, and they support the contention of the existence of a specific transport system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01692863
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Acetylcholine and histamine are transmitter candidates in identifiable mechanosensitive neurons of the spider Cupiennius salei: an immunocytochemical study (1997)
    Springer
    Cell & tissue research 287 (1997), S. 413-423 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Choline acetyltransferase ; Acetylcholinesterase ; Histochemistry ; Serotonin ; Mechanoreceptors ; Lipofuscin ; Cupiennius salei (Chelicerata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Histochemical and indirect immunocytochemical techniques were used to search for neuroactive substances and transmitter candidates in identified sensory neurons of two types of cuticular mechanoreceptors in the spider Cupiennius salei Keys.: (1) in lyriform slit-sense organ VS-3 (comprising 7-8 cuticular slits each innervated by 2 bipolar neurons), and (2) in tactile hairs (each supplied by 3 bipolar sensory cells). All neurons are mechanosensitive. A polyclonal antibody against choline acetyltransferase (ChAT) strongly labeled all cell bodies and afferent fibers of both mechanoreceptor types. Western blot analysis using the same antibody against samples of spider sensory hypodermis and against samples from the central nervous system demonstrated a clear band at 65 kDa, corresponding to the molecular mass of ChAT in insects. Moreover, staining for acetylcholine esterase (AChE) revealed AChE activity in one neuron of each mechanoreceptor type. Incubation with a polyclonal antibody against histamine clearly labeled one neuron in each set of sensilla, whereas activity in the remaining one or two cells was near background. All mechanoreceptor preparations treated with a polyclonal antiserum against serotonin tested negative, whereas sections through the central nervous system of the same spiders were clearly labeled for serotonin. The presence of ChAT-like immunoreactivity and AChE implicates acetylcholine as a transmitter candidate in the two mechanoreceptive organs. We assume that histamine serves as a mechanosensory co-transmitter in the central nervous system and may also act at peripheral synapses that exist in these sensilla.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050766
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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