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  • 1995-1999  (3)
  • 1985-1989
  • Cyclodextrinase  (2)
  • ADHD  (1)
  • 1
    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
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  • 2
    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
    Library Location Call Number Volume/Issue/Year Availability
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of abnormal child psychology 26 (1998), S. 345-356 
    ISSN: 1573-2835
    Keywords: ADHD ; DSM-III-R ; persistence ; comorbidity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Abstract A large school-based sample of children in Grades 1, 2, 3, and 4 were screened for disruptive behavior and subsequently assessed over a 5-year period for DSM-III-R symptoms of attention deficit hyperactivity disorder (ADHD) and other externalizing and internalizing behavior disorders. Parents completed structured diagnostic interviews in Years 1, 4, and 5, and teachers completed Behavioral Assessment for Children—Teacher Rating Scales behavioral ratings annually. For parent-derived diagnostic data, both inattention and hyperactivity/impulsivity symptom groups declined from Year 1 to Year 4, with hyperactivity showing more significant decline. For teacher-rated behavioral dimensions, the Attention Problems scale declined from Year 1 to Year 3 and stabilized thereafter. The Hyperactivity scale showed stability during the first 3 years before declining in Year 4. Of those children diagnosed with ADHD in Year 1, 69% still met criteria for ADHD in either Year 4 or 5. Persisters were more likely to exhibit coexisting conduct disorder in Year 1 and oppositional defiant disorder in Years 1, 4, and 5. Parents of persisters reported more psychosocial adversity on measures of parenting and marital satisfaction.
    Type of Medium: Electronic Resource
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