Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytochemical localization of wheat germ agglutinin binding sites in the cell wall of Candida albicans was investigated with fluorescence and electron microscopy. Various analytical techniques were employed in order to obtain a good penetration of the cytochemical markers, glycosylated horseradish peroxidase or glycosylated ferritin. In blastospores sectioned by cryostatic methods, a weak and continuous labelling of the blastospore periphery was observed with peroxidase, whereas bud scars and inner cell wall areas were labelled with ferritin. Following enzymatic treatment with pronase whose efficiency was followed by the periodic acid-thiocarbohydrazide -- Silver proteinate technique, the inner cell wall layers of bud are strongly stained with both fluorescein and the reactions products of peroxidase. After pronase-chitinase treatment, fluorescence was observed only in the mother cell wall. Finally, ultrathin glycol methacrylate sections showed a labelling both in inner and outer layers. All these results suggest that chitin was essentially distributed in the inner wall layers near the plasmalemma and in a smaller amount in outer wall layers. On the basis of the present findings, a hypothesis of wall assembly is proposed.
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PMID:Localization of chitin in the cell wall of Candida albicans by means of wheat germ agglutinin. Fluorescence and ultrastructural studies. 703 73

The biosynthesis of cognate glycoproteins with chitinase-sensitive carbohydrate moiety ("chitinoproteins") was detected after incubation of cultured cells of different insect species with 3H-glucosamine (Kramerov et al., Insect Biochem. v. 20; 769-775, 1990). It was also demonstrated that production of the specific chitinoprotein takes place during the development of D. melanogaster as revealed by immunoblotting and autoradiographic analysis of crude tissue extracts. An investigation of the developmental pattern of tissue localization of Drosophila chitinoprotein was performed using antibodies raised in rabbit after immunization with a purified preparation of the chitinoprotein (ChiP) from Drosophila embryonic cultured cells. The paraffin-embedded thin (5 microns) sections of organisms fixed in Bouin fixative were stained immunohistochemically with primary antibodies and peroxidase-conjugated secondary antibodies followed by enhancement of the precipitated DAB product with osmium tetroxide. Preimmune serum and antiserum preadsorbed with the purified ChiP preparation were used as negative controls yielding no specific staining of tissue sections. Negative staining with specific anti-ChiP antibodies was demonstrated for salivary glands, gut, muscles, central and peripheral nerve system and some other tissues. A complex pattern of tissue-specific ChiP localization in a variety of tissues of ectodermal, mesodermal and germ line origin was revealed. The mesodermal derivatives--hemocytes and oenocytes capable of producing the components of cuticle as well as epidermal cells of larvae and imago clearly demonstrated staining of cytoplasmic vesicles, which in the latter case were exocytosed and included into the newly formed endocuticle. Another cell type known to produce cuticle--epithelial cells of imaginal discs (primordia of adult organs)--were also stained with antibodies. One can suppose that ChiP is involved in biogenesis of insect cuticle, probably, as a protein precursor of chitin formation. It was quite surprising to observe a rather strong staining of fat body cells and follicle cells of adult ovaries. The follicular epithelium secreted the stained granules into a growing oocyte that accumulated large amounts of this immunopositive material until transformation into a mature egg. In an early embryo ChiP is localized in blastodermal and pole cells, but not in yolk. This is, probably, the result of segregation of ChiP to the periphery of an egg during the final stage of its maturation and subsequent cellularization in the beginning of embryogenesis. Later ChiP can be found in ectodermal cells and hemocyte-like cells. It should be noted that not all amounts of ChiP detected in embryos are maternally inherited, for an active ChiP biosynthesis takes place in dissociated embryonic cells after incubation with labelled sugar precursor.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[The tissue localization of "chitinoprotein", detectable by using specific antibodies, in the development of Drosophila melanogaster]. 848 11

Molecular size and net charge of isoforms of pathogenesis-related (PR) chitinase, beta-1,3-glucanase and peroxidase were studied in uninfected barley (Hordeum vulgare L., v. Karat) leaves and in barley leaves infected with the pathogenic fungus Drechslera teres f. teres (Sacch.) Shoem. Molecular characteristics were determined by time-dependent polyacrylamide gradient gel electrophoresis under native conditions and by applying an extended version of the computer program MOL-MASS (Rothe, G. M., Weidmann, H., Electrophoresis 1991, 12, 703-709). Uninfected barley leaves contained predominantly one peroxidase isozyme but also three very weak peroxidases. Activities of all of these three peroxidases increased considerably after infection with Drechslera teres. The molecular masses of peroxidases 1 and 3 were estimated to be 38 +/- 5 and 42 +/- 7 kDa and their apparent valences at pH 8.4 were Z = 3.13 and 3.20, respectively. Amongst the chitinase isoforms, chitinase 1 and chitinase 2 appeared after infection, while chitinase 3 was also observed in uninfected leaves of barley. The molecular mass of chitinase 3 (31 +/- 6 kDa; f/fo = 1.20) was larger than that of chitinase 1 (20 +/- 2 kDa; f/fo = 1.04) and chitinase 2 (23 +/- 3 kDa; f/fo = 1.06). The valence of constitutive chitinase 3 (Z = 1.44 +/- 0.81) at pH 8.4 was lower than that of adaptive chitinase 1 (Z = 3.27 +/- 1.02) and chitinase 2 (Z = 2.96 +/- 1.38). Infection of barley leaves with Drechslera teres also induced the hydrolytic enzyme beta-1,3-glucanase 1; beta-1,3-glucanase 2 appeared in uninfected and in infected leaves. Constitutive beta-1,3-glucanase 2 was smaller (molecular mass 19 +/- kDa; f/fo = 1.05) than adaptive beta-1,3-glucanase 1 (molecular mass 26 +/- 4 kDa; f/fo = 1.07). The valence of adaptive beta-1,3-glucanase 1 (Z = 9.58 +/- 4.17) was approximately threefold that of beta-1,3-glucanase 2 (Z = 2.80 +/- 0.93).
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PMID:Molecular size and net charge of pathogenesis-related enzymes from barley (Hordeum vulgare L., v. Karat) infected with Drechslera teres f. teres (Sacch.) Shoem. 962 9

To understand the coordinated functions of the different classes of defense-related genes expressed in plant disease resistance, the expression patterns of pathogenesis related (PR) protein genes and genes involved in antioxidation and the production of secondary metabolites were examined. The expression patterns of the respective defense-related genes were monitored following TMV infection or salicylic acid treatment. Northern blot analyses showed that PR genes such as PR-1, beta-1,3-glucanase and chitinase were strongly induced in tobacco leaves upon TMV infection or salicylic acid treatment. 3-Hydroxy-3-methylglutaryl CoA reductase (HMGR) and phenylalanine ammonialyase (PAL), involved in isoprenoid and phenylpropanoid biosynthesis, respectively, were mildly induced at the late stage of normal hypersensitive response (HR) or after salicylic acid treatment when compared with the PR-gene expressions. However, in acute HR, they were strongly expressed at the early stage. Interestingly, the expression of the antioxidative genes, anionic peroxidase and ascorbate peroxidase, were inversely expressed following TMV infection and salicylic acid treatment. Differential expression of 3 groups of genes involved in plant defense responses are discussed in relation to different signal transduction pathways.
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PMID:Coordinated expression of defense-related genes by TMV infection or salicylic acid treatment in tobacco. 974 24

The potential of the biocontrol agent Trichoderma harzianum T-203 to trigger plant defense responses was investigated by inoculating roots of cucumber seedlings with Trichoderma in an aseptic, hydroponic system. Trichoderma-treated plants were more developed than nontreated plants throughout the experiment. Electron microscopy of ultrathin sections from Trichoderma-treated roots revealed penetration of Trichoderma into the roots, restricted mainly to the epidermis and outer cortex. Strengthening of the epidermal and cortical cell walls was observed, as was the deposition of newly formed barriers. These typical host reactions were found beyond the sites of potential fungal penetration. Wall appositions contained large amounts of callose and infiltrations of cellulose. The wall-bound chitin in Trichoderma hyphae was preserved, even when the hyphae had undergone substantial disorganization. Biochemical analyses revealed that inoculation with Trichoderma initiated increased peroxidase and chitinase activities within 48 and 72 h, respectively. These results were observed for both the roots and the leaves of treated seedlings, providing evidence that T. harzianum may induce systemic resistance mechanisms in cucumber plants.
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PMID:Induction of defense responses in cucumber plants (Cucumis sativus L. ) By the biocontrol agent trichoderma harzianum 1004 64

Fusarium head blight (FHB) of wheat is a crippling disease that causes severe economic losses in many of the wheat-growing regions of the world. Temporal patterns of fungus development and transcript accumulation of defense response genes were studied in Fusarium graminearum-inoculated wheat spikes within the first 48 to 76 h after inoculation (hai). Microscopy of inoculated glumes revealed that the fungus appeared to penetrate through stomata, exhibited subcuticular growth along stomatal rows, colonized glume parenchyma cells, and sporulated within 48 to 76 hai. No major differences in the timing of these events were found between Sumai 3 (resistant) and Wheaton (susceptible) genotypes. In complementary experiments, RNA was extracted from spikes at several time intervals up to 48 hai and temporal expression patterns were determined for defense response genes encoding peroxidase, PR-1, PR-2 (beta-1,3-glucanase), PR-3 (chitinase), PR-4, and PR-5 (thaumatin-like protein). In both genotypes, transcripts for the six defense response genes accumulated as early as 6 to 12 hai during F. graminearum infection and peaked at 36 to 48 hai. Greater and earlier PR-4 and PR-5 transcript accumulation was observed in Sumai 3, compared with Wheaton. Our results show that the timing of defense response gene induction is correlated with F. graminearum infection.
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PMID:Fungal development and induction of defense response genes during early infection of wheat spikes by Fusarium graminearum. 1065 6

A cell suspension culture of a tobacco (Nicotiana tabacum L. cv. Petit Havana) cell line derived from a cultivar transformed with the Tcyt gene from Agrobacterium, which leads to high endogenous levels of cytokinin, has been established. This cell line shows increased cell aggregation, elongated cells and a 5-fold increase in wall thickness. If allowed to carry on growing it can form a single mass without shedding cells into the medium. When analysed at an earlier growth stage, these cultures were found to produce improved levels of vascular nodule formation than in other systems that employ exogenous cytokinin. This differentiation was optimised with respect to sucrose and auxin signals in order to induce maximum production of cells with thickened walls and a morphology characteristic of fibre cells and tracheids, in addition to cells that remain meristematic. In order to establish the validity of this system for studying secondary wall formation, the walls and associated biosynthetic changes were analysed in these cells by chemical analysis of the walls, changes in activities of enzymes of xylan and monolignol synthesis, and expression of mRNAs coding for enzymes of lignin biosynthesis. The wall composition of the transformed cells was compared with that determined for primary walls from a typical untransformed tobacco cell line. Recovery of wall material was 50% greater in the transformed culture. In this material a major difference was found in the pectin fraction where there was a distinct difference in size distribution together with a lower level of methylation for the transformed line, which may be related to increased adhesiveness. There were increased amounts of xylan, although the ratio of xyloglucan to xylan content was not substantially different due to the mixture of cell types. There was also an increase in cellulose and phenolic components. Increased activity of enzymes involved in the synthesis of xylan as a marker for the secondary wall occurred around the time of tracheid differentiation and coincided with a broad peak of cinnamyl alcohol dehydrogenase activity. The expression of mRNAs coding for enzymes of the general phenylpropanoid pathway, phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, catechol O-methyl transferase was relatively constitutive in the cultures while transcripts of ferulate 5-hydroxylase, cinnamoyl CoA-reductase, cinnamyl alcohol dehydrogenase and lignin peroxidase were induced. The walls of the transformed cells also showed considerable differences in the subset of extractable proteins from that found in primary walls of tobacco when these were subjected to proteomic analysis. Many of these proteins appear to be novel and not present in primary walls. However an Mr-32,000 chitinase, an Mr-34,000 peroxidase, an Mr-65,000 polyphenoloxidase/laccase and possibly an Mr-68,000 xylanase could be identified as well as structural proteins.
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PMID:Proteomic analysis reveals a novel set of cell wall proteins in a transformed tobacco cell culture that synthesises secondary walls as determined by biochemical and morphological parameters. 1128 5

Water deficit (WD) in Lupinus albus L. brings about tissue-specific responses that are dependent on stress intensity. Carbohydrate metabolism is very sensitive to changes in plant water status. Six days from withholding water (DAW), sucrose, glucose and fructose levels of the leaf blade had already increased over 5-fold, and the activities of SS and INV(A) had increased c. 1.5-2 times. From 9 DAW on, when stress intensity was more pronounced, these effects were reversed with fructose and glucose concentrations as well as INV(A) activity dropping in parallel. The stem (specifically the stele) responded to the stress intensification with striking increases in the concentration of sugars, N and S, and in the induction of thaumatin-like-protein and an increase in chitinase and peroxidase. At 13 DAW, the plants lost most of the leaves but on rewatering they fully recovered. Thus, the observed changes appear to contribute to a general mechanism of survival under drought, the stem playing a key role in that process.
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PMID:Alterations in carbon and nitrogen metabolism induced by water deficit in the stems and leaves of Lupinus albus L. 1143 22

The maize rhm1 mutant resists Bipolaris maydis, the causal agent of Southern corn leaf blight, by producing small necrotic lesions surrounded by chlorotic haloes. The rhm1 and wild-type lesions contain viable fungus in equal frequency, but fungal sporulation was markedly inhibited on rhm1. The levels of the pathogenesis-related (PR) proteins chitinase, PR1, and peroxidase differ little between rhm1 and wild type, with or without B. maydis inoculation. The global mRNA profiles surveyed revealed hundreds of cDNA fragments that were twofold or more induced or suppressed in rhm1 and wild-type plants following B. maydis inoculation. Nonetheless, between rhm1 and wild type, only 0.4 to 0.7% of the cDNA fragments were expressed differentially by twofold or more. Among the up-regulated genes in rhm1 was beta-glucosidase glu1, which prompted a test of whether rhm1 resistance depends upon the antimicrobial compound 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one or other hydroxamic acids whose glucosyl conjugates are preferred substrates for the Glu1 enzyme. Double mutants of rhm1 and bx1, a hydroxamic acid-deficient mutant, indicate that rhm1 resistance is hydroxamic acid independent. The rhm1 resistance presently appears to operate via a mechanism unlike those of previously described resistance genes.
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PMID:Maize rhm1 resistance to Bipolaris maydis is associated with few differences in pathogenesis-related proteins and global mRNA profiles. 1149 66

Infiltration of cellulase (EC 3.2.1.4) from Trichoderma longibrachiatum into melon (Cucumis melo) cotyledons induced several key defense mechanisms and hypersensitive reaction-like symptoms. An oxidative burst was observed 3 hours after treatment and was followed by activation of ethylene and salicylic acid (SA) signaling pathways leading to marked induction of peroxidase and chitinase activities. The treatment of cotyledons by heat-denatured cellulase also led to some induction of peroxidase and chitinase activities, but the oxidative burst and SA production were not observed. Co-infiltration of aminoethoxyvinil-glycine (an ethylene inhibitor) with the active cellulase did not affect the high increase of peroxidase and chitinase activities. In contrast, co-infiltration of aminoethoxyvinil-glycine with the denatured enzyme blocked peroxidase and chitinase activities. Our data suggest that the SA pathway (induced by the cellulase activity) and ethylene pathway (induced by heat-denatured and active protein) together coordinate the activation of defense mechanisms. We found a partial interaction between both signaling pathways since SA caused an inhibition of the ethylene production and a decrease in peroxidase activity when co-infiltrated with denatured cellulase. Treatments with active or denatured cellulase caused a reduction in powdery mildew (Sphaerotheca fuliginea) disease.
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PMID:Salicylic acid and ethylene pathways are differentially activated in melon cotyledons by active or heat-denatured cellulase from Trichoderma longibrachiatum. 1155 61


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