Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.15 (pectinase)
2,440 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two filamentous, branched, and septate actinomycetes were isolated from field-collected and from axenic in vitro produced root nodules of Alnus crispa var. mollis Fern. host plant. After their transfer to a chemically defined medium, these nodule isolates could not be distinguished from each other on the basis of morphology, cultural reactions, and whole cell composition and were considered to be the same species. They were morphologically similar to the root nodule endophyte, but were incapable of nodulating aseptic host plants growing in a nitrogen-deficient substrate. Whole cells of the nodule isolates were used for the production of rabbit antibodies. The resulting specific antiisolate antibodies were conjugated with fluorescein isothiocyanate and used in staining tests of the nodule endophyte. The immunofluorescence reactions demonstrated the homology of the nodule isolates with the nodule endophyte. After pectinase degradation of the endophyte capsule, the indirect immunoferritin method corroborated the fluorescent anti-body (FA) staining reactions. There was no antigenic relationship between the nodule isolates and 13 known strains of actinomycetes as determined by the FA techique. Fluorescent antibody reactions of adsorbed conjugates suggested that endophytes of both Alnus crispa var. mollis Fern. and Alnus rugosa (DuRoi) Spreng. root nodules belong to a common serotype. The LL and mesoisomers of diaminopimelic acid were present in similar proportions in the nodule endophyte and in the nodule isolates. Glucose, mannose, and an unknown sugar were the predominant whole cell sugars in the nodule isolates, although trace amounts of arabinose and rhamnose were also displayed. The unknown sugar found in the nodule isolates was also present in trace amounts in the endophyte-suspension hydrolysate.
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PMID:Demonstration of the isolation of non-infective Alnus crispa var. mollis Fern, nodule endophyte by morphological immunolabelling and whole cell composition studies. 122 Aug 59

To depolymerize plant pectin, the phytopathogenic enterobacterium Erwinia chrysanthemi produces a series of enzymes which include a pectin-methyl-esterase encoded by the pem gene and five isoenzymes of pectate lyases encoded by the five genes pelA, pelB, pelC, pelD, and pelE. We have constructed transcriptional fusions between the pectinase gene promoters and the uidA gene, encoding beta-glucuronidase, to study the regulation of these E. chrysanthemi pectinase genes individually. The transcription of the pectinase genes is dependent on many environmental conditions. All the fusions were induced by pectic catabolic products and responded, to different degrees, to growth phase, catabolite repression, temperature, and nitrogen starvation. Transcription of pelA, pelD, and pelE was also increased in anaerobic growth conditions. High osmolarity of the culture medium increased expression of pelE but decreased that of pelD; the other pectinase genes were not affected. The level of expression of each gene was different. Transcription of pelA was very low under all growth conditions. The expression of the pelB, pelC, and pem genes was intermediate. The pelE gene had a high basal level of expression. Expression of pelD was generally the most affected by changes in culture conditions and showed a low basal level but very high induced levels. These differences in the expression of the pectinase genes of E. chrysanthemi 3937 presumably reflect their role during infection of plants, because the degradation of pectic polymers of the plant cell walls is the main determinant of tissue maceration caused by soft rot erwiniae.
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PMID:Environmental conditions affect transcription of the pectinase genes of Erwinia chrysanthemi 3937. 144 47

Small bacteriocin is a low-molecular-weight bacteriocin which is common in fast-growing rhizobia. As its activity could not be detected in chloroform-sterilized culture supernatants (P.R. Hirsch, J. Gen. Microbiol. 113:219-228, 1979), the bacteriocin could not be purified in order to study its mechanism of action. We report here that small is soluble in chloroform, an observation which led to effective and simple (partial) purification. Other properties of small are its low molecular weight, which is estimated to be between 700 and 1,500, its resistance to proteolytic enzymes, pectinase, and lysozyme, and its heat stability at pH 5.5 but not at pH 7.0. Its bactericidal action on exponentially growing sensitive cells was not detected until 11 h after its addition. The bactericidal action was preceded by inhibition of cell division. To determine whether small activity is required for nodulation or nitrogen fixation, a transposon Tn5-induced small-negative mutant was isolated. The observation that this strain formed normal, acetylene-reducing root nodules showed that small production is not a prerequisite for the formation of effective nodules.
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PMID:Bacteriocin small of fast-growing rhizobia is chloroform soluble and is not required for effective nodulation. 399 74

To depolymerize plant pectin, the phytopathogenic enterobacterium Erwinia chrysanthemi produces five isoenzymes of pectate lyases encoded by the five genes pelA, pelB, pelC, pelD and pelE. In Er. chrysanthemi, all genes involved in pectin degradation are specifically controlled by the KdgR repressor and are induced in the presence of a pectin catabolic product, 2-keto-3-deoxygluconate (KDG). transcription of the pectinase genes is dependent on many environmental conditions. Transcriptional fusions present on low-copy-number plasmids were used to study the regulation of the pel genes in a heterologous host, Escherichia coli. Some physiological regulations that take place in Er. chrysanthemi are conserved in E. coli. The five pel fusions in E. coli are affected by growth phase, catabolite repression and anaerobic growth conditions and are induced in the presence of galacturonate, a sugar whose catabolism leads to the formation of KDG, the inducer of pel transcription in Er. chrysanthemi. Expression of pelE increased with the osmolarity of the culture medium. In contrast, the regulation of pel expression by temperature or nitrogen starvation, observed in Er. chrysanthemi, was not conserved in E. coli, suggesting that the mechanisms responsible for these regulations are specific to Er. chrysanthemi. Analysis of different E. coli mutants allowed some regulators affecting the transcription of the pel genes to be identified. In E. coli, the growth-phase regulation of the pel genes is not dependent on the RpoS sigma factor and the fnr gene is not involved in the increase of pel expression in oxygen-limited conditions. The gene hns, involved in the regulation of numerous genes, appears to affect pel expression but the effects of E. coli hns mutations are not related to osmoregulation. In contrast, this analysis clearly demonstrates the interchangeability of two regulatory systems of E. coli and Er. chrysanthemi: the global control exerted by the catabolite activator protein CAP and the specific regulation mediated by the KdgR repressor.
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PMID:Regulatory systems modulating the transcription of the pectinase genes of Erwinia chrysanthemi are conserved in Escherichia coli. 882 30

Erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pel4, pelB, pelC, pelD, and pelE genes and a set of secondary pectate lyases, two of which, pelL and pelZ, have been already identified. We cloned the pelI gene, encoding a ninth pectate lyase of E. chrysanthemi 3937. The pelI reading frame is 1,035 bases long, corresponding to a protein of 344 amino acids including a typical amino-terminal signal sequence of 19 amino acids. The purified mature PelI protein has an isoelectric point of about 9 and an apparent molecular mass of 34 kDa. PelI has a preference for partially methyl esterified pectin and presents an endo-cleaving activity with an alkaline pH optimum and an absolute requirement for Ca2+ ions. PelI is an extracellular protein secreted by the Out secretory pathway of E. chrysanthemi. The PelI protein is very active in the maceration of plant tissues. A pelI mutant displayed reduced pathogenicity on chicory leaves, but its virulence did not appear to be affected on potato tubers or Saintpaulia ionantha plants. The pelI gene constitutes an independent transcriptional unit. As shown for the other pel genes, the transcription of pelI is dependent on various environmental conditions. It is induced by pectic catabolic products and affected by growth phase, oxygen limitation, temperature, nitrogen starvation, and catabolite repression. Regulation of pelI expression appeared to be dependent on the three repressors of pectinase synthesis, KdgR, PecS, and PecT, and on the global activator of sugar catabolism, cyclic AMP receptor protein. A functional KdgR binding site was identified close to the putative pelI promoter. Analysis of the amino acid sequence of PelI revealed high homology with a pectate lyase from Erwinia carotovora subsp. carotovora (65% identity) and low homology with pectate lyases of the phytopathogenic fungus Nectria haematococca (Fusarium solani). This finding indicates that PelI belongs to pectate lyase class III. Using immunoblotting experiments, we detected PelI homologs in various strains of E. chrysanthemi and E. carotovora subsp. carotovora but not in E. carotovora subsp. atroseptica.
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PMID:Pectate lyase PelI of Erwinia chrysanthemi 3937 belongs to a new family. 939 96

The polymorphic fungus Aureobasidium pullulans ATHUM 2915, produced significant quantities of extracellular polygalacturonase and polysaccharide when grown, under controlled conditions, in liquid medium with pectin and glucose as carbon sources and nitrogen source as limited factor. Growth, substrate consumption and products formation were simulated by a structured mathematical model, which was compared with the experimental data from batch culture in a chemostat. This model was applied successfully in the study of some essential parameters influenced the process at various pH values.
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PMID:Modelling of simultaneous production of polygalacturonase and exopolysaccharide by Aureobasidium pullulans ATHUM 2915. 971 73

Erwinia chrysanthemi 3937 secretes several pectinolytic enzymes, among which eight isoenzymes of pectate lyases with an endo-cleaving mode (PelA, PelB, PelC, PelD, PelE, PelI, PelL, and PelZ) have been identified. Two exo-cleaving enzymes, the exopolygalacturonate lyase, PelX, and an exo-poly-alpha-D-galacturonosidase, PehX, have been previously identified in other E. chrysanthemi strains. Using a genomic bank of a 3937 mutant with the major pel genes deleted, we cloned a pectinase gene identified as pelX, encoding the exopolygalacturonate lyase. The deduced amino acid sequence of the 3937 PelX is very similar to the PelX of another E. chrysanthemi strain, EC16, except in the 43 C-terminal amino acids. PelX also has homology to the endo-pectate lyase PelL of E. chrysanthemi but has a N-terminal extension of 324 residues. The transcription of pelX, analyzed by gene fusions, is dependent on several environmental conditions. It is induced by pectic catabolic products and affected by growth phase, oxygen limitation, nitrogen starvation, and catabolite repression. Regulation of pelX expression is dependent on the KdgR repressor, which controls almost all the steps of pectin catabolism, and on the global activator of sugar catabolism, cyclic AMP receptor protein. In contrast, PecS and PecT, two repressors of the transcription of most pectate lyase genes, are not involved in pelX expression. The pelX mutant displayed reduced pathogenicity on chicory leaves, but its virulence on potato tubers or Saintpaulia ionantha plants did not appear to be affected. The purified PelX protein has no maceration activity on plant tissues. Tetragalacturonate is the best substrate of PelX, but PelX also has good activity on longer oligomers. Therefore, the estimated number of binding subsites for PelX is 4, extending from subsites -2 to +2. PelX and PehX were shown to be localized in the periplasm of E. chrysanthemi 3937. PelX catalyzed the formation of unsaturated digalacturonates by attack from the reducing end of the substrate, while PehX released digalacturonates by attack from the nonreducing end of the substrate. Thus, the two types of exo-degrading enzymes appeared complementary in the degradation of pectic polymers, since they act on both extremities of the polymeric chain.
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PMID:Characterization of the exopolygalacturonate lyase PelX of Erwinia chrysanthemi 3937. 1004

Erwinia chrysanthemi 3937 secretes an arsenal of pectinolytic enzymes including several pectate lyases encoded by the pel genes. We characterized a novel cluster of pectinolytic genes consisting of the three adjacent genes pehV, pehW and pehX, whose products have polygalacturonase activity. The high similarity between the three genes suggests that they result from duplication of an ancestral gene. The transcription of pehV, pehW and pehX is dependent on several environmental conditions. They are induced by pectin catabolic products and this induction results from inactivation of the KdgR repressor which controls almost all the steps of pectin catabolism. The presence of calcium ions strongly reduced the transcription of the three peh genes. Their expression was also affected by growth phase, osmolarity, oxygen limitation and nitrogen starvation. In addition, the pehX transcription is affected by catabolite repression and controlled by the activator protein CRP. PecS, which was initially isolated as a repressor of virulence factors, acts as an activator of the peh transcription. We showed that the three regulators KdgR, PecS and CRP act by direct interaction with the promoter regions of the peh genes. Analysis of simultaneous binding of KdgR, PecS, CRP and RNA polymerase indicated that the activator effect of PecS results from a competition between PecS and KdgR for the occupation of overlapping binding sites. Thus, to activate peh transcription, PecS behaves as an anti-repressor against KdgR.
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PMID:Analysis of three clustered polygalacturonase genes in Erwinia chrysanthemi 3937 revealed an anti-repressor function for the PecS regulator. 1056 5

The gene prt1 was isolated from the tomato vascular wilt fungus Fusarium oxysporum f. sp. lycopersici, whose predicted amino acid sequence shows significant homology with subtilisin-like fungal proteinases. Prt1 is a single-copy gene, and its structure is highly conserved among different formae speciales of F. oxysporum. Prt1 is expressed constitutively at low levels during growth on different carbon and nitrogen sources and strongly induced in medium containing collagen and glucose. As shown by reverse transcription-polymerase chain reaction and fluorescence microscopy of F. oxysporum strains carrying a prt1-promoter-green fluorescent protein fusion, prt1 is expressed at low levels during the entire cycle of infection on tomato plants. F. oxysporum strains transformed with an expression vector containing the prt1 coding region fused to the inducible endopolygalacturonase pg1 gene promoter and grown under promoter-inducing conditions secreted high levels of extracellular subtilase activity that resolved into a single peak of pI 4.0 upon isoelectric focusing. The active fraction produced two clearing bands of 29 and 32 kDa in sodium dodecyl sulfate gels containing gelatin. Targeted inactivation of prt1 in F. oxysporum f. sp. lycopersici had no detectable effect on mycelial growth, sporulation, and pathogenicity on tomato plants.
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PMID:Molecular characterization of a subtilase from the vascular wilt fungus Fusarium oxysporum. 1133 29

Production of an extracellular pectinase by wood-rot fungi of the genus Bjerkandera and Coriolus was studied. The active producers B. adusta 40 and C. versicolor 24 were selected. The dynamics of production of pectinase and effects of temperature, initial pH, humidity of the medium and addition of nitrogen sources on the biosynthesis of pectinase were studied.
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PMID:[Biosynthesis of pectinase by fungi Bjerkandera and Coriolus by solid phase fermentation]. 1177 23


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