Endochitinase from Aspergillus nidulans implicated in the autolysis of its cell wall

Reyes, Fuensanta; Calatayud, Jose; Martı́nez, Marı́a Jesús

doi:10.1016/0378-1097(89)90088-8

Cited by 20 publications

(14 citation statements)

References 31 publications

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“…These results suggest that the enzyme consists of two identical subunits. Molecular weight standards: 1, dextran blue (2000000); 2, a-globulin (150000); 3, bovine albumin (67000); and 4, cytochrome c (12300) Most B-N-acetylglucosaminidases from filamentous fungi have molecular weights between 140 000 and 190 000 (Jones and Kosrnan 1980;Reyes et al 1989).…”

Section: Resultsmentioning

confidence: 99%

A β-N-acetylhexosaminidase from Penicillium oxalicum implicated in its cell-wall degradation

Rodríguez

Copa-Patiño

Reyes

et al. 1994

Lett Appl Microbiol

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High β‐N‐acetylhexosaminidase (EC.3.2.1.52) activity was detected during autolysis of Penicillium oxalicum. Purification of the enzyme to homogeneity yielded an enzyme with a molecular weight of 132 000 Da by gel filtration and 71 900 Da by SDS polyacrylamide gel electrophoresis, suggesting a dimeric structure. The enzyme is an acidic protein with a pl of 5.0. Optimal activity was at pH 4.0 and 40°C, with a Km of 0.80 mmol 1‐1 for p‐nitrophenyl‐β‐N‐acetylglucosaminide and 1.03 mmol 1‐1 for p‐nitrophenyl‐β‐N‐acetylgalactosaminide. The Ki with the competitive inhibitor O‐(2‐acetamido‐2‐deoxy‐D‐glucopyranosylidene) amino‐N‐phenylcarbamate was 1 μmol 1‐1. Hg2+, Ag+ and Fe3+ were effective inhibitors. β‐N‐acetylhexosaminidase hydrolysed chitobiose, chitotriose, chitotetrose and chitopentose to monomer to an extent of 92, 74, 44 and 17% respectively in 40 min. This enzyme, in conjunction with a purified endochitinase from P. oxalicum, hydrolysed a cell‐wall chitin fraction isolated from this fungus, with the production of N‐acetylglucosamine.

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Section: Resultsmentioning

confidence: 99%

A β-N-acetylhexosaminidase from Penicillium oxalicum implicated in its cell-wall degradation

Rodríguez

Copa-Patiño

Reyes

et al. 1994

Lett Appl Microbiol

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“…The thickening of the chitin layer within the wall might be a consequence of two independent events. Namely, the equilibrium between cell wall biosynthesis and lysis (BartnickiGarcía, 1973(BartnickiGarcía, , 1999Peter and Schweikart, 1990) might be thrown out of balance because cryptic growth continued during carbon starvation (Pusztahelyi et al, 1997a, b;White et al, 1999), and/or the autolytic degradation of cell wall matrix polymers (Harvey et al, 1998;Reyes et al, 1988Reyes et al, , 1989 was hindered by the chitinase inhibitor. The increased chitin content of the cells together with the substantial inhibition of chitinases (IC 50 ϭ1.4 mM for extracellular enzymes) preceded the blockage of growth observed later, after glucose supplementation at 115 h of incubation (Fig.…”

Section: Discussionmentioning

confidence: 99%

Autolysis and aging of Penicillium chrysogenum cultures under carbon starvation: Chitinase production and antifungal effect of allosamidin.

Sámi

Pusztahelyi

Emri

et al. 2001

J. Gen. Appl. Microbiol.

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IntroductionThe autolysis taking place in submerged carbon-depleted cultures of Penicillium chrysogenum is influenced by numerous intrinsic (vacuolation, age-related hydrolase production, aging) and extrinsic (power input, shearing forces, nutrient and O 2 limitations, penicillin side-chain precursors) factors (Harvey et al., 1998;McIntyre et al., 1999McIntyre et al., , 2000Nielsen and Krabben, 1995;Paul et al., 1994;Paul and Thomas, 1996;Pócsi et al., 2000; Pusztahelyi et al., 1997a, b;White et al., 1999). In some aspects, the autolysis of P. chrysogenum is reminiscent of the apoptosis of higher eucaryotes under these conditions, e.g., it is an en- In carbon-depleted cultures of Penicillium chrysogenum, age-related chitinases were shown to play a crucial role in both autolysis and fragmentation as indicated by in vivo enzyme inhibition experiments using allosamidin. This pseudotrisaccharide even hindered significantly the outgrowth of new hyphal tips from the surviving yeastlike fragments after glucose supplementation. The antifungal effect of allosamidin on autolyzing P. chrysogenum mycelia was fungistatic rather than fungicidal. In growing hyphae, membrane-bound microsomal chitinase zymogen(s) were detected, which may be indicative of some compartmentalization of these hydrolases. Later, during autolysis, no zymogenic chitinase was detected in any enzyme fraction studied, including microsomes. These observations may explain the different sensitivity of growing and autolyzing mycelia to allosamidin. Chitinases taking part in the age-related fragmentation of hyphae and the outgrowth of surviving hyphal fragments seem to be potent targets for future antifungal drug research. Autolysis and aging of

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“…ChiA is a glycosylphosphatidylinositol-anchored chitinase that functions in cell wall remodeling and/or cell wall maturation (40). Another chitinase, a 27-kDa endochitinase purified from the autolytic cultures of A. nidulans, was shown to have the ability to hydrolyze the cell wall chitin (29). In addition, NagA (N-acetyl-␤-D-glucosaminidase [9]) was shown to play a role in morphogenesis and nutrient utilization during autolysis (28).…”

Section: Vol 8 2009 Fungal Autolysis and Cell Death 741mentioning

confidence: 99%

Differential Roles of the ChiB Chitinase in Autolysis and Cell Death of Aspergillus nidulans

et al. 2009

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Autolysis is a natural event that occurs in most filamentous fungi. Such self-degradation of fungal cells becomes a predominant phenomenon in the absence of the regulator of G protein signaling FlbA in Aspergillus nidulans. Among a number of potential hydrolytic enzymes in the A. nidulans genome, the secreted endochitinase ChiB was shown to play a major role in autolysis. In this report, we investigate the roles of ChiB in fungal autolysis and cell death processes through genetic, biochemical, and cellular analyses using a set of critical mutants. Determination of mycelial mass revealed that, while the flbA deletion (⌬flbA) mutant autolyzed completely after a 3-day incubation, the ⌬flbA ⌬chiB double mutant escaped from hyphal disintegration. These results indicate that ChiB is necessary for the ⌬flbA-induced autolysis. However, importantly, both ⌬flbA and ⌬flbA ⌬chiB strains displayed dramatically reduced cell viability compared to the wild type. These imply that ChiB is dispensable for cell death and that autolysis and cell death are separate processes. Liquid chromatography-tandem mass spectrometry analyses of the proteins that accumulate at high levels in the ⌬flbA and ⌬flbA ⌬chiB mutants identify chitinase (ChiB), dipeptidyl peptidase V (DppV), O-glycosyl compound hydrolase, ␤-N-acetylhexosaminidase (NagA), and myo-inositol-1-phosphate synthase (InoB). Functional characterization of these four genes reveals that the deletion of nagA results in reduced cell death. A working model bridging G protein signaling and players in autolysis/cell death is proposed.

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Endochitinase from Aspergillus nidulans implicated in the autolysis of its cell wall

Cited by 20 publications

References 31 publications

A β-N-acetylhexosaminidase from Penicillium oxalicum implicated in its cell-wall degradation

A β-N-acetylhexosaminidase from Penicillium oxalicum implicated in its cell-wall degradation

Autolysis and aging of Penicillium chrysogenum cultures under carbon starvation: Chitinase production and antifungal effect of allosamidin.

Differential Roles of the ChiB Chitinase in Autolysis and Cell Death of Aspergillus nidulans

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