Substances in dead plant tissue that stimulate infection of French bean leaves by Botrytis cinerea

1987 ◽  
Vol 93 (3) ◽  
pp. 135-146 ◽  
Author(s):  
J. Heuvel
Keyword(s):  
Botrytis Cinerea ◽  
Plant Tissue ◽  
French Bean ◽  
Dead Plant ◽  
Bean Leaves

Purification and characterization of a constitutive polygalacturonase associated with the infection process of French bean leaves by Botrytis cinerea

1990 ◽  
Vol 68 (9) ◽  
pp. 1921-1930 ◽  
Author(s):  
G. Leone ◽  
E. A. M. Schoffelmeer ◽  
J. Van den Heuvel
Keyword(s):  
Botrytis Cinerea ◽  
Reaction Rate ◽  
French Bean ◽  
Infection Process ◽  
Purification Procedure ◽  
Purification And Characterization ◽  
Titration Curves ◽  
Optimal Ph ◽  
Bean Leaves

The constitutively produced polygalacturonase isoenzyme PG2 was isolated from culture filtrates of Botrytis cinerea, purified to homogeneity, and characterized. The shape of titration curves of PG2 and two other polygalacturonase isoenzymes explained the difficulties found in separating superimposed pectic enzyme activities during the purification procedure. PG2 hydrolyzed sodium polygalacturonate more quickly than pectin. The optimal pH for PG2 activity with polygalacturonate was 4.5 and with pectin, 4.0. PG2 activity was also influenced by the presence of NaCl or CaCl2 in the reaction mixture. Analysis of the breakdown products by paper chromatography and a comparison of the reaction rate by viscosimetry and reducing group assay revealed that PG2 has an endocatalytic mode of action on polygalacturonate. The isoelectric point and the molecular mass of PG2 were estimated to be 9.1 and 23.0 kDa, respectively. Key words: Botrytis cinerea, chromatofocusing, endopolygalacturonase, purification, substrate specificity, titration curve.

scholarly journals Radiochemical determination of a unique sequence around the reactive serine residue of a di-isopropyl phosphorofluoridate-sensitive plant carboxypeptidase and a yeast peptidase

1972 ◽  
Vol 128 (2) ◽  
pp. 229-235 ◽  
Author(s):  
D. C. Shaw ◽  
J. R. E. Wells
Keyword(s):  
Amino Acids ◽  
French Bean ◽  
Unique Sequence ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Serine Carboxypeptidase ◽  
Serine Residue ◽  
Radiochemical Determination ◽  
Bean Leaves

Phaseolain, a carboxypeptidase from French-bean leaves, and a partially purified peptidase from baker's yeast are inhibited by reaction with di-isopropyl phosphorofluoridate. Radioactive di-isopropyl [32P]phosphorofluoridate was used to show that the site of reaction is a unique serine residue and that the sequence of amino acids adjacent to the reactive serine is Glu-Ser-Tyr. This sequence is different from those of other ‘serine’ enzymes previously reported and, for phaseolain, represents an unequivocal example of a ‘serine’ carboxypeptidase.

The evolution of cellulose digestion in insects

1991 ◽  
Vol 333 (1267) ◽  
pp. 281-288 ◽  
Keyword(s):  
Plant Tissue ◽  
Cellulose Digestion ◽  
Biochemical Studies ◽  
Growing Body ◽  
Dead Plant ◽  
Abundance And Diversity

Despite the abundance and diversity of species that include living or dead plant tissue in their diets, the ability to digest cellulose is rare in insects and is restricted to a small number of orders and families. In this paper it is argued that cellulolytic capacity is uncommon in insects simply because it is a trait that is rarely advantageous to possess. Although there is a growing body of evidence for the occurrence of symbiont-independent cellulose digestion in cockroaches and in higher termites from the subfamily Nasutitermitinae, cellulose digestion in insects is usually mediated by microorganisms. It is proposed that non-cellulolytic omnivorous scavengers and detritivores may be preadapted to evolve symbiont-mediated cellulolytic mechanisms because of the prevalence of mutualistic associations between such species and the microorganisms that normally reside in their hindguts. A scenario is proposed for the evolution of symbiont-mediated cellulolytic capacity in roaches and lower termites. Finally, it is suggested that biochemical studies of insect cellulases might provide crucial insights that would greatly advance our understanding of the evolution of cellulose digestion in insects.

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