Heavy metals and thiol compounds in Mucor racemosus and Articulospora tetracladia

Miersch, J.; Tschimedbalshir, Munchtul; Bärlocher, Feli×; Grams, Ylva Y.; Pierau, Bianca; Schierhorn, Angelika; Krauss, Gerd-J.

doi:10.1017/s095375620100404x

Cited by 46 publications

(25 citation statements)

References 35 publications

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“…Possibly, deposited pollutants were leached or otherwise removed from the transferred leaves. Or, they were immobilized or inactivated by the invading fungal community, for example, by the accumulation of thiol-containing compounds (MIERSCH et al, 1997(MIERSCH et al, , 2001. Leaves preinoculated with one of three pure cultures had much higher decay rates, which exceeded even those of leaves that had been exposed at H8 for the entire period.…”

Section: Discussionmentioning

confidence: 99%

Response of Aquatic Hyphomycete Communities to Changes in Heavy Metal Exposure

Sridhar

Bärlocher

Krauss

2005

International Review of Hydrobiology

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Decomposition of Alnus glutinosa (alder) leaves was studied in a severely (site H4) and a moderately (site H8) heavy metal polluted stream in the former copper shale mining district of Mansfeld, Central Germany. Leaves at H8 had reduced fungal diversity and spore production but a high exponential decay rate (k = 0.065). No further mass loss of leaves occurred at H4 after 4 -6 weeks, and fungal diversity and spore production were lower than in H8. Decay and sporulation rates gradually increased to values of H8 control leaves in leaves preincubated in H4 and then transferred to H8. These increases correlated with the invasion of transplanted leaves by Tetracladium marchalianum and Tricladium angulatum. In the reverse transplant experiment (H8 to H4), mass loss appeared to stop immediately. Sporulation rates also declined, but remained consistently above levels in H4 control leaves. Leaves precolonized in the laboratory by one of three aquatic hyphomycete species exhibited increased decay rates in both streams. Sporulation rates on these leaves were greater than those of control leaves in H4, but smaller than those of control leaves in H8. IntroductionAquatic hyphomycetes, an ecologically defined group of asexually reproducing fungi, play a crucial role in the decomposition and transformation of leaves and other allochthonous plant material in streams (BÄRLOCHER, 1992a;CAI et al., 2003; TSUI and HYDE, 2003). Fungal biomass on newly exposed leaves increases to a peak (up to 17% of detrital dry mass, GESSNER, 1997) within a few weeks. It remains at this level for some time before gradually declining. In addition to increasing their mycelial biomass, the fungi release large numbers of conidia (up to 8 µg -1 detrital mass; GESSNER, 1997). Generally, more than 90% of all conidia released on any given date belong to 1-4 species (BÄRLOCHER, 1992b). There is some evidence of species replacement: certain species may be selectively inhibited or favoured by seasonal changes in temperature (WEBSTER et al., 1976;SUBERKROPP, 1984), or an extended residence time may allow a substrate to accumulate more rare species (BÄR-LOCHER, 1980). More commonly, the fungal community changes because of shifts in the relative frequencies of occurrence of species that arrive early and persist throughout the leaf's decay. This underlines the importance of early resource capture, confirmed by stream expo-

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Section: Discussionmentioning

confidence: 99%

Response of Aquatic Hyphomycete Communities to Changes in Heavy Metal Exposure

Sridhar

Bärlocher

Krauss

2005

International Review of Hydrobiology

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“…The resulting loss of ecological function, however, may be compensated for by increased contributions of the winning species. By contrast, even moderate increases in background levels of heavy metals depress biological activity across broad taxonomic boundaries, e.g., plants (Clemens 2001), fungi (Perego & Howell 1997, Gadd & Sayer 2000, Miersch et al 2001) and bacteria (Nies 1999). While some species may be extinguished and others may develop resistance, the overall performance, on balance, is likely to decline below prepollution levels.…”

Section: Discussionmentioning

confidence: 99%

Decomposition of alder leaves in two heavy metal-polluted streams in central Germany

Sridhar

Bärlocher

Raviraja

et al. 2001

Aquat. Microb. Ecol.

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In the former copper shale mining district of Mansfeld, central Germany, weathering of slag heaps and dumps resulted in groundwater, lakes and streams with extremely high heavy metal and metalloid concentrations (Zn up to 2.6 g l -1; Cu, Pb, Cs, Cd, As up to 13 mg l -1 ). We followed decomposition of Alnus glutinosa leaves in 2 streams, one with a high (H4) and one with a moderate (H9) load of these metals. In H9, mass loss closely followed an exponential decay curve (k = 0.055 d -1 ); in H4, leaf mass remained constant after a very rapid initial decay (k = 0.12) during the first 4 wk. Fungal biomass, estimated by ergosterol measurements, reached values of up to 1.1% (H9) or 0.36% (H4) of total detrital mass, corresponding to 6 and 2%, respectively, of maxima reported from nonpolluted streams. Conidium production by aquatic hyphomycetes was reduced to 10% (H9) and 0.01% (H4) of highest literature values. After 4 wk of stream exposure, leaves had greatly increased levels of As, Cu, Fe, Mn (both streams), Pb and Zn (H4). Gammarus fossarum preferred leaves that had been conditioned in the stream for 2 (H9) or 4 (H4) wk over unconditioned leaves.

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“…GSH possesses multiple functions and is involved in, e.g., antioxidative defence, cell proliferation, and chelation of metal ions (Penninckx 2002;Schu¨tzendu¨bel & Polle 2002). It is further the direct precursor of glutathione-related PCs [(c-Glu-Cys) n -Gly, where n = 2-11] also reported for filamentous fungi (Cobbett & Goldsbrough 2002;Gadd 2001;Miersch et al 2001;Mu¨nger & Lerch 1985). Whereas the bioinduction of cysteine-rich peptides in yeasts, filamentous fungi, some basidiomycetes, and ectomycorrhizal fungi has been demonstrated, to date only very limited information is available about heavy metal-detoxifying principles in wood-rotting fungi (Mu¨nger & Lerch 1985;Gadd 2001).…”

Section: Introductionmentioning

confidence: 96%

Species-specific Cd-stress Response in the White Rot Basidiomycetes Abortiporus biennis and Cerrena unicolor

et al. 2006

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The effect of cadmium (Cd) on fungal growth, Cd bioaccumulation and biosorption, and on the formation of potential heavy metal response indicators such as thiols, oxalate, and laccase was investigated in the white rot fungi Cerrena unicolor andAbortiporus biennis. Only the highest Cd concentration employed (200 microM) inhibited growth of C. unicolor, whereas already lower Cd concentrations caused decreasing mycelia dry weights in A. biennis. Cd biosorption onto the mycelial surface was the predominant Cd sequestration mechanism in C. unicolor. Surface-bound and bioaccumulated Cd concentrations were essentially in the same range in A. biennis, leading to considerably higher intracellular Cd concentrations in A. biennis than in C. unicolor. Oxalate and laccase were produced by both of the fungal strains and their extracellular levels were elevated upon Cd exposure. Oxalate concentrations and laccase titres were considerably higher in C. unicolor than in A. biennis. Both fungi responded to increasing Cd concentrations by increasing intracellular amounts of thiol compounds (cysteine, gamma-glutamylcysteine, glutathione in both its reduced and oxidized form) but Cd application increased the amounts of thiols to a higher extend in A. biennis. Taken together, these species-specific responses towards Cd suggest that C. unicolor possesses a more efficient system than A. biennis to keep intracellular Cd concentrations low.

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Heavy metals and thiol compounds in Mucor racemosus and Articulospora tetracladia

Cited by 46 publications

References 35 publications

Response of Aquatic Hyphomycete Communities to Changes in Heavy Metal Exposure

Response of Aquatic Hyphomycete Communities to Changes in Heavy Metal Exposure

Decomposition of alder leaves in two heavy metal-polluted streams in central Germany

Species-specific Cd-stress Response in the White Rot Basidiomycetes Abortiporus biennis and Cerrena unicolor

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