β-N-Acetylhexosaminidase: A target for the design of antifungal agents

Horsch, Markus; Mayer, Christoph; Sennhauser, U.; Rast, Dora M.

doi:10.1016/s0163-7258(97)00110-1

Cited by 86 publications

(47 citation statements)

References 201 publications

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“…The cell walls of ascomycete fungi contain a mixture of fibrillar components and amorphous or matrix materials (Horsch et al, 1997). The main fibrillar component is chitin, a straight-chain b(1,4)-linked polymer of N-acetylglucosamine.…”

Section: Discussionmentioning

confidence: 99%

“…Filamentous fungi grow by extension at the flexible apex of the hypha, a process that requires remodelling of the fibrillar chitin component of the cell wall to allow extension at the growing tip. This remodelling requires coordinated production of constitutive chitinase enzymes such as N-acetyl-b-D-glucosaminidase and endochitinase, in addition to biosynthetic chitin synthases (Horsch et al, 1997;Rast et al, 1991) and b-glucan synthases (Wessels, 1994). Consequently, a deficiency in Nacetyl-b-D-glucosaminidase in GD12 appears to result in abnormal remodelling of the hyphal tip and would account for the intense staining with calcofluor white found in the swollen hyphal apices of the DThnag : : hph mutant, indicative of aberrant chitin deposition.…”

Section: Discussionmentioning

confidence: 99%

“…The spore concentration of axenic cultures of the wild-type strain was 2.7610 7 spores ml 21 . Chitin is a structural component of the cell wall of Trichoderma species and N-acetyl-b-D-glucosaminidase is one of a number of chitinase enzymes that are believed to play a role in cell wall turn-over and remodelling during hyphal development (Reyes et al, 1989a, b;Rast et al, 1991;Sahai & Manocha, 1993;Horsch et al, 1997;White et al, 2002). To test whether N-acetyl-b-D-glucosaminidase functions in cell wall biogenesis of this fungus, GD12 and DThnag : : hph mycelia were inoculated onto standard medium containing calcofluor white, and sensitivity was assessed over a 4 day period.…”

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Saprotrophic competitiveness and biocontrol fitness of a genetically modified strain of the plant-growth-promoting fungus Trichoderma hamatum GD12

et al. 2012

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Trichoderma species are ubiquitous soil fungi that hold enormous potential for the development of credible alternatives to agrochemicals and synthetic fertilizers in sustainable crop production. In this paper, we show that substantial improvements in plant productivity can be met by genetic modification of a plant-growth-promoting and biocontrol strain of Trichoderma hamatum, but that these improvements are obtained in the absence of disease pressure only. Using a quantitative monoclonal antibody-based ELISA, we show that an N-acetyl-b-D-glucosaminidase-deficient mutant of T. hamatum, generated by insertional mutagenesis of the corresponding gene, has impaired saprotrophic competitiveness during antagonistic interactions with Rhizoctonia solani in soil. Furthermore, its fitness as a biocontrol agent of the pre-emergence damping-off pathogen Sclerotinia sclerotiorum is significantly reduced, and its ability to promote plant growth is constrained by the presence of both pathogens. This work shows that while gains in T. hamatummediated plant-growth-promotion can be met through genetic manipulation of a single beneficial trait, such a modification has negative impacts on other aspects of its biology and ecology that contribute to its success as a saprotrophic competitor and antagonist of soil-borne pathogens. The work has important implications for fungal morphogenesis, demonstrating a clear link between hyphal architecture and secretory potential. Furthermore, it highlights the need for a holistic approach to the development of genetically modified Trichoderma strains for use as crop stimulants and biocontrol agents in plant agriculture. INTRODUCTIONTrichoderma species are ubiquitous soil saprotrophs that have attracted sustained scientific interest as biological control agents of plant disease. In addition to their biocontrol properties, certain strains have been shown to enhance crop productivity by stimulating plant growth (Contreras-Cornejo et al., 2009;Harman et al., 2004;Ortíz-Castro et al., 2009;Vinale et al., 2008Vinale et al., , 2009. While genetic modification of Trichoderma strains by constitutive overexpression of chitinase, b-glucanase and proteinase genes has allowed the development of strains with improved biocontrol capabilities (Flores et al., 1997;Baek et al., 1999;Limó n et al., 1999;Viterbo et al., 2001;Djonović et al., 2007), less attention has been paid to enhancing the plantgrowth-promoting (P-G-P) activities of these fungi via genetic modification, and the impact that any such modification might have on their saprotrophic competence and fitness as biocontrol agents.In a previous study, we showed that a naturally occurring strain of Trichoderma hamatum was able to promote plant growth in low pH, nutrient-poor peat soils (Thornton, 2008). These soils contain a significant pool of nitrogen sequestered in chitin of insect and fungal origin (Kerley & Read, 1998), and fungal N-acetyl-b-D-glucosaminidase has been shown to be a key chitinolytic enzyme releasing sequestered nitrogen for assimilation ...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Saprotrophic competitiveness and biocontrol fitness of a genetically modified strain of the plant-growth-promoting fungus Trichoderma hamatum GD12

et al. 2012

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“…In contrast, the culture extracts of the four fungal strains showed broad inhibitory spectra similar to known GlcNAcase inhibitors. 18) The presence of inhibitors specific for insect GlcNAcases strongly suggested distinct differences between the GlcNAcases of insects and those of other organisms including plants, fungi and mammals. A similar phenomenon was revealed in our previous study in which a novel insect chitinase inhibitor FPS-1 inhibited the insect chitinase from S. litura but not the actinomycete chitinase from Streptomyces griseus.…”

Section: Inhibitory Spectra Of Active Compoundsmentioning

confidence: 99%

Screening and partial characterization of inhibitors of insect .BETA.-N-acetylglucosaminidase

et al. 2006

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IntroductionChitin, a linear polysaccharide of b(1,4)-linked N-acetylglucosamine residues, is a structural component of the cuticle and the peritrophic membrane in the mid-gut of insects, and the strict regulation of its metabolism is essential for the normal growth of insects. The chitinolytic enzyme system consisting of chitinase and b-N-acetylglucosaminidase (GlcNAcase) is essential for the metabolic turnover of chitin in insects, and hence, inhibitors of these enzymes are expected to be potential insect growth regulators (IGRs). Over the past few years, chitinases have been regarded as potential target enzymes for IGRs since the hydrolysis of chitin by the enzymes is considered the rate-determining step in the degradation of chitin. Although several compounds such as allosamidin, 1) argifin 2,3) and argadin 4) have already been discovered as chitinase inhibitors, none have been used commercially as IGRs. One reason for this is that these compounds inhibit family 18 chitinases of many different organisms. 5,6) We have previously isolated a novel chitinase inhibitor, FPS-1, from the culture filtrate of Sphaeropsis sp. TNPT116-Cz.7) FPS-1 potently inhibited an insect chitinase from Spodoptera litura (common cutworm), but did not inhibit an actinomycete chitinase from Streptomyces griseus. In contrast, the known chitinase inhibitor allosamidin potently inhibited both chitinases. These results indicated that the insect chitinase was apparently distinct from the chitinases of other organisms.GlcNAcase forming part of the chitinolytic enzyme system is necessary for the complete degradation of chitin into its monosaccharide, but little attention has been given to it as a target enzyme for new IGRs because of its wide distribution in nature including fungi, actinomycetes, plants and mammals. However, the presence of the insect chitinase inhibitor FPS-1 strongly suggested that the chitinolytic enzyme system in insects consists of a unique chitinase and GlcNAcase. The question then arises, are there enzyme inhibitors specific for the insect GlcNAcase in nature?This paper reports on the screening and partial characterization of inhibitors specific for the GlcNAcase of insect origin. Materials and Methods GeneralNagstatin was a gift from Microbial Chemistry Research Foundation (Japan). Pupae of Adoxophyes orana and Musca J. Pestic. Sci., 31(1), 41-46 (2006) Screening and partial characterization of inhibitors of insect b b -N-acetylglucosaminidase Microbial culture broths were screened for novel b-N-acetylglucosaminidase (GlcNAcase) inhibitors specific for the enzyme of insect origin. Four strains of actinomycetes, Streptomyces griseoloalbus JCM4480, S. clauifer JCM5059, S. anulatus NBRC13369 and S. griseus subsp. rhodochrous NBRC13849, produced unique compounds showing selective inhibition of the insect GlcNAcase. In contrast, 4 fungal strains, Paecilomyces sp. F13, F30, P. carneus F2281 and Verticillium sp. F40, were found to produce GlcNAcase inhibitors showing a broad spectrum of inhibitory activity against GlcNAc...

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“…Chitinase is a potential antifungal agent that can be isolated from a wide range of organisms. (HORSCH et al,1997;HARMAN et al,2004;LI, 2006;MERZENDORFER et al,2003;RAST et al,2003). Further screening of microbes for enzymes, has received ever-increasing interest.…”

Section: Introductionmentioning

confidence: 99%

Production and partial purification of antifungal chitinase from Bacillus cereus VITSD3

Devi¹,

Srinivasan²,

Archana³

et al. 2015

Biosci. J.

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ABSTRACT:The current work was designed to isolate and characterize chitin degrading bacteria. Among the 55 bacterial colonies isolated from 7 different soil samples, 4 isolates were capable of degrading chitinase, among which one strain VITSD3 was found to be potent. Based on the morphological, biochemical and molecular characterization of VITSD3 the isolate was confirmed as Bacillus cereus (Genbank accession number: KC961638), designated as Bacillus cereus VITSD3. The crude enzyme had a total activity of 220 U, precipitated with 44.8 U and 22.5 U for dialysed sample. The hydrolysed product NAG (N-Acetyl Glucosamine) from chitin was analysed by high-pressure liquid chromatography (HPLC).The molecular weight of the chitinase was determined using SDS PAGE and found to be 55 kDa. The partially purified chitinase produced from Bacillus cereus VITSD3 showed antifungal activity against Aspergillus fumigatus (18 mm), Aspergillus niger (6 mm) and Aspergillus flavus (15 mm). Hence the investigation suggests a potential benefit of partially purified chitinase extracted from Bacillus cereus VITSD3 which will serve as an excellent antifungal potential with therapeutic use.

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β-N-Acetylhexosaminidase: A target for the design of antifungal agents

Cited by 86 publications

References 201 publications

Saprotrophic competitiveness and biocontrol fitness of a genetically modified strain of the plant-growth-promoting fungus Trichoderma hamatum GD12

Saprotrophic competitiveness and biocontrol fitness of a genetically modified strain of the plant-growth-promoting fungus Trichoderma hamatum GD12

Screening and partial characterization of inhibitors of insect .BETA.-N-acetylglucosaminidase

Production and partial purification of antifungal chitinase from Bacillus cereus VITSD3

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