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1995 (1)
1994 (1)
1Author    A. Kio, K. Obayashi, K. Ohki, A. Kiyam, K. Azuyoshi, K. Aw AzuRequires cookie*
 Title    Partially N-Deacetylated Chitin Fragments are Strong Elicitors for (+)-Pisatin Induction in Epicotyls of Pea  
 Abstract    Chitosan derivatives classed into three groups according to their molecular size were exam­ ined for the relationships between degree of N -acetylation and phytoalexin (+)-pisatin-induc-ing activity in pea epicotyl assay. Partially N-deacetylated chitin with degree o f N-acetylation 56% (DAC 56%) was the most potent inducer o f (+)-pisatin am ong sparingly water-soluble polysaccharides including chitosan (degree o f N -acetylation 0%), DAC 32%, and chitin. Among the intermediate-sized molecules obtained from degradation of the chitosan and the DACs by N a N 0 2, the chitosan fragment was the most powerful elicitor for (+)-pisatin induc­ tion. The N a N 0 2-degraded DAC 56% exhibited a com parable activity to the N a N 0 2 -degrad-ed chitosan at low concentrations. The N a N 0 2-degraded fragments as well as the native poly­ mer induced a relatively high am ount of (+)-pisatin, while the acetone precipitate of chitosan oligomers from the HCl-catalyzed hydrolysate and their partially N-acetylated derivatives ex­ hibited a m oderate (+)-pisatin-inducing activity. These findings suggest the possibility that partially N-deacetylated chitin fragments could be one o f the most promising elicitors in the pea system. 
  Reference    Z. Naturforsch. 49c, 302—308 (1994); received January 14/February 24 1994 
  Published    1994 
  Keywords    Elicitor, Chitosan, Chitin Pea, Phytoalexin 
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 TEI-XML for    default:Reihe_C/49/ZNC-1994-49c-0302.pdf 
 Identifier    ZNC-1994-49c-0302 
 Volume    49 
2Author    Kohki Akiyamaa, Kazuyoshi Kawazua, Akio KobayashibRequires cookie*
 Title    Partially N-Deacetylated Chitin Oligomers (Pentamer to Heptamer) are Potential Elicitors for (+)-Pisatin Induction in Pea Epicotyls  
 Abstract    Oligomers (dimer to heptamer) of chitosan and their partially/completely N-acetylated derivatives were examined for (+)-pisatin-inducing activities in pea epicotyl elicitor assay at concentrations ranging from 6.25 to 100 j.ig/ml. The structures of the oligomers were analyzed by 'H NM R and M A L D I TOF MS spectrometers. The chitosan oligomers from dimer to tetramer were inactive, while the pentamer exhibited a moderate activity at 100 |ig/ml. The hexamer showed a pronounced activity at 100 |ag/ml, whereas the oligomer had no activity at the higher concentrations. Although the chitosan heptamer induced a moderate amount of (+)-pisatin (ca. 60 j.ig/g fr. wt.) at 50 (.ig/ml, the oligomer did not elicit pisatin formation at 100 |ig/ml. The dimer to tetramer of both partially N-deacetylated chitin (DAC) and chitin were totally inactive. The DAC pentamers (d.a. 31%, 52%), DAC hexamers (d.a. 26%, 41%), and DAC heptamers (d.a. 26%, 36%) exhibited significant elicitor activities at lower concen­ trations (6.25-25 [.ig/ml) than the native chitosan oligomers. The chitin pentamer to heptamer had weak or no activity. Both glucosamine and N-acetylglucosamine were inactive in the assay. These facts suggest that the DAC pentamer to heptamer may act as elicitors for pisatin induction in pea-fungus interactions. 
  Reference    Z. Naturforsch. 50c, 391—397 (1995); received January 4/January 15 1995 
  Published    1995 
  Keywords    Elicitor, Chitosan, Chitin, Phytoalexin, Pisum sativum 
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 TEI-XML for    default:Reihe_C/50/ZNC-1995-50c-0391.pdf 
 Identifier    ZNC-1995-50c-0391 
 Volume    50