Dry Mycelium Research Articles

Transcriptomic comparison of Aspergillus niger growing on two different sugars reveals coordinated regulation of the secretory pathway

BackgroundThe filamentous fungus, Aspergillus niger, responds to nutrient availability by modulating secretion of various substrate degrading hydrolases. This ability has made it an important organism in industrial production of secreted glycoproteins. The recent publication of the A. niger genome sequence and availability of microarrays allow high resolution studies of transcriptional regulation of basal cellular processes, like those of glycoprotein synthesis and secretion. It is known that the activities of certain secretory pathway enzymes involved N-glycosylation are elevated in response to carbon source induced secretion of the glycoprotein glucoamylase. We have investigated whether carbon source dependent enhancement of protein secretion can lead to upregulation of secretory pathway elements extending beyond those involved in N-glycosylation.ResultsThis study compares the physiology and transcriptome of A. niger growing at the same specific growth rate (0.16 h-1) on xylose or maltose in carbon-limited chemostat cultures. Transcription profiles were obtained using Affymetrix GeneChip analysis of six replicate cultures for each of the two growth-limiting carbon sources. The production rate of extracellular proteins per gram dry mycelium was about three times higher on maltose compared to xylose. The defined culture conditions resulted in high reproducibility, discriminating even low-fold differences in transcription, which is characteristic of genes encoding basal cellular functions. This included elements in the secretory pathway and central metabolic pathways. Increased protein secretion on maltose was accompanied by induced transcription of > 90 genes related to protein secretion. The upregulated genes encode key elements in protein translocation to the endoplasmic reticulum (ER), folding, N-glycosylation, quality control, and vesicle packaging and transport between ER and Golgi. The induction effect of maltose resembles the unfolded protein response (UPR), which results from ER-stress and has previously been defined by treatment with chemicals interfering with folding of glycoproteins or by expression of heterologous proteins.ConclusionWe show that upregulation of secretory pathway genes also occurs in conditions inducing secretion of endogenous glycoproteins – representing a more normal physiological state. Transcriptional regulation of protein synthesis and secretory pathway genes may thus reflect a general mechanism for modulation of secretion capacity in response to the conditional need for extracellular enzymes.

Nitrous oxide production by fungi in soils under different moisture levels

The production of nitrous oxide (N2O) by facultative anaerobic fungi from the Fusarium, Trichoderma, and Paecylomyces genera was detected. Representatives of the genus Mucorales did not produce N2O. The formation of N2O in sterile soddy-podzolic soil inoculated by Fusarium oxysporum and F. solani increased significantly with the rise of the soil water content from 16–20% (50–60% of the field water capacity) to 30% (the field water capacity) with maximum values reached at the water content of 50% (the total soil water capacity). The production of N2O by fungi at the soil water content of 50% was often higher under microaerobic conditions than under anaerobic conditions created via substitution of argon for atmospheric air in the flasks. The activity of N2O production by fungi in the soil increased by several times upon nitrite or nitrate amendments. The specific activity of N2 O formation in the soil was 0.38 ± 0.15 nmol N2O/(h per mg) of dry mycelium. It was significantly lower than the rate of N2O formation by Fusarium oxysporum 11dn1 in the nitrite-containing media and close to the rate of N2O formation by this fungus in the nitrate-containing media. A comparison of the rate of N2O release by active strain Fusarium oxysporum 11dn1 inoculated into the sterile soil with the rate of denitrification processes in the nonsterile soil showed that the contribution of soil fungi to the total emission of gaseous nitrogen compounds from the soil may reach 8% under optimum conditions.

Control of Aspergillus flavus with essential oil and methanol extract of Satureja hortensis

The essential oil and methanol extract of Satureja hortensis were tested for antifungal activity against Aspergillus flavus in vitro on Petri plates and liquid culture, and under storage conditions. The oil showed strong antifungal activity based on the inhibition zone and minimal inhibitory concentration values against the pathogen on Petri plates assays. The very low concentrations of them also reduced wet and dry mycelium weight of pathogen fungus in liquid culture. When the oils at 25, 12.5 and 6.25 µl/mL concentrations were applied to lemon fruits before seven days of pathogen inoculation on storage conditions, the decay on fruits caused by the pathogen could be prevent completely. The results in this study showed that the essential oil of S. hortensis had strong antifungal activity against pathogen fungi tested. So, the essential oil of S. hortensis could be used for management of this pathogen as a potential source of sustainable eco-friendly botanical fungicides.

Phoma tracheiphila

<i>Phoma tracheiphila</i>

Integrative Extraction of Ergosterol, (1→3)-α-D-Glucan and Chitosan from Penicillium chrysogenum Mycelia

Ergosterol,(1→3)-α-D-glucan and chitosan are important biomaterials. In this research, a process has been developed to integratively extract ergosterol, (1→3)-α-D-glucan, and chitosan from Penicillium chrysongenum mycelium. First, the mycelia are pretreated with 0.1mol · L −1 of NaOH. After recovery by centrifugation, the solid portion is made to undergo saponification and deacetylation reactions by addition of 2mol · L −1 NaOH and ethanol. After reaction, extraction is carried out by addition of petroleum ether, which separates the reaction mixture into two phases. The upper layer of petroleum ether contains extracted ergosterol, and the bottom layer of NaOH solution contains (1→3)-α-D-glucan; the chitosan is on the mycelia residuum. After isolation, the recovery yield of ergosterol is 0.52% of dry mycelium. That of (1→3)-α-D-glucan is about 8.2%; and chitosan is 5.7% with 86% deacetylation. The compositions have been characterized by IR, HPLC analyses.

Resolution of ( R, S)-flurbiprofen catalysed by dry mycelia in organic solvent

Mycelia of Aspergillus oryzae display high enantioselectivity towards ( R)-flurbiprofen and can be efficiently used in pure organic solvent for the resolution of ( R, S)-flurbiprofen through esterification. The use of the lyophilized mycelia facilitates the separation process so that in one step the two enantiomers of flurbiprofen, which are both valuable for pharmaceutical applications, can be easily separated. The biotransformation can be carried out in different apolar solvents using different primary alcohols as nucleophiles under very mild conditions.

Decolorization of synthetic dyes by white rot fungi, involving laccase enzyme in the process

In this study, decolorization of Remazol Brillant Blue Royal (RBBR) and Drimaren Blue CL-BR (DB) was investigated using three white rot fungi named as Pleurotus ostreatus ( P. ostreatus), Coriolus versicolor ( C. versicolor) and Funalia trogii ( F. trogii). Decolorization studies were continued for 48 h under static conditions at 30 °C and pH 5.0. The degree of pH, dry mycelium weight (DMW), dye concentration, laccase activity and protein content were analyzed; the enzyme responsible for decolorization was detected for both dyes. Maximum and minimum decolorizations were obtained by F. trogii and P. ostreatus, respectively. Both dyes at all concentrations were found to be toxic for P. ostreatus growth, whereas only DB above 60 mg/L was found to be toxic for C. versicolor growth. Maximum and minimum laccase activities were detected in decolorization media of F. trogii and P. ostreatus, respectively. Results of activity staining following SDS-PAGE showed that laccase is the only enzyme that is responsible for decolorization of DB and RBBR.

Cadmium(II) Removal by a Hyperaccumulator Fungus Phoma sp. F2 Isolated from Blende Soil

A cadmium(II)-resistant fungus, strain F2, isolated from blende soil was identified as Phoma sp. by morphological study and internal transcribed spacer sequencing. This strain could accumulate 280 mg of Cd(II)/g dry weight mycelium. In liquid medium containing 163.8 mg Cd(II)/L, 96% of Cd(II) was removed by the actively growing mycelium. In addition, both oven-dried and lyophilized mycelium could effectively adsorb Cd(II). There were removed 91% and 46.2% of Cd(II) from 51.6 mg Cd(II)/L solution by lyophilized biomass and oven-dried biomass respectively. Transmission electron microscopy and energy-dispersive X-ray analysis showed the accumulation of Cd(II) in the mycelium cell walls. Our results demonstrated that Phoma sp. F2 was a hyperaccumulator for the removal of Cd(II) from contaminated soil and water.

First Report of Southern Blight Caused by Sclerotium rolfsii on Hemp (Cannabis sativa) in Sicily and Southern Italy.

Hemp (Cannabis sativa L.), family Cannabaceae, is an annual herbaceous plant that is 1.5 to 4.0 m tall and native to the Caucasus Region, northern India, and Iran. It is cultivated in warm to temperate regions worldwide for its fiber, oil, and psychoactive substances. In Europe, commercial plantings have decreased from 52,872 ha in 1989 to 18,716 ha in 2005. Recently however, cultivation of hemp as a natural fiber species has been encouraged by European Union policy (2). During the summer of 2003, patches of dead plants were observed in test plots of 12 monoecious and dioecious hemp cultivars (Beniko, Epsylon 68, Felina 34, Ferimon, Fedora 17, Futura 75, Bialobrzeskie, Dioica 88, Fibranova, Tiborszallasi, Lovrin, and Carmagnola) in an experimental field near Catania (eastern Sicily) previously planted to artichoke (Cynara scolymus L.). Plots were irrigated with a drip irrigation system. Symptoms were first detected in July with day/night temperatures between 35 and 26°C. Infected plants showed a dark brown-to-tan discoloration of the stem near the soil line. As disease progressed, the rot extended down to the crown and taproot, foliage became yellow, and the entire plant eventually collapsed. An extensive white, cottony mycelium and numerous spherical tan-to-dark brown sclerotia (0.5 to 4.0 mm in diameter) developed externally on infected tissues and soil. As much as 60% of the plants were affected in a single plot. Monoecious cultivars that had been planted earlier escaped the disease. Isolations from diseased tissues were performed by plating symptomatic tissues previously disinfected for 1 min in 1% NaOCl and rinsed in sterile water on acidified potato dextrose agar (pH 4.5). Isolations consistently yielded a fungus whose characters corresponded to Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough). Pathogenicity of two isolates obtained from infected plants was confirmed by inoculating 120-day-old hemp plants grown in individual pots. Twenty plants for each of the above listed cultivars (10 plants for each isolate) were inoculated by applying toothpick tips (5 mm) colonized by S. rolfsii to the lower part of the stem. Ten noninoculated plants served as controls. Plants were kept in a greenhouse with temperatures between 26 and 32°C and 95% relative humidity. High soil moisture was maintained with frequent watering. All inoculated plants showed blight and basal stem rot after 2 weeks, irrespective of the cultivar. By the third week, plants began to dry up and mycelium and sclerotia developed on the crown. Noninoculated controls remained symptomless. S. rolfsii was reisolated from inoculated plants. Although S. rolfsii has been reported on hemp in India since the 1930s (3), to our knowledge, this is the first report of southern blight caused by this fungus on C. sativa in Sicily and southern Italy. Residues of artichoke, a very susceptible host of S. rolfsii (1), might have been the source of inoculum for this outbreak on hemp. Most likely, high summer temperatures and overirrigation exacerbated the disease severity.

Submerged culture conditions for mycelial yield and polysaccharides production by Lyophyllum decastes

The effects of various carbon and nitrogen sources, their concentrations, initial pH and fermentation duration on the production of mycelia in terms of dry weight, exo-polysaccharide (EPS) and inner polysaccharide (IPS) by Lyophyllum decastes, a culinary-medicinal mushroom, were investigated in shake-flask cultures. Lactose, glucose and fructose were the top three best carbon sources for mycelial growth with corresponding yields of 6.73 g/l, 6.36 g/l and 6.10 g/l, respectively. Glucose was the best for production of EPS and IPS with 1.65 g/l and 317 mg/g dry mycelia, respectively. Maltose also performed well for EPS production. Yeast extract was the best nitrogen source for the production of mycelia (7.03 g/l) and IPS (325 mg/g dry mycelia), whereas EPS was improved further by increasing the yeast extract concentration (2.46 g/l at 2%). Similarly, initial pH 7 and 8 were best for polysaccharides production (EPS 1.73 g/l and IPS 320 mg/g) and mycelial growth (7.10 g/l), respectively. Maximum mycelial growth peaked at 15 days of cultivation whereas polysaccharides peaked at 10 days, and then tapered off. A concentration of glucose 3% and yeast extract 1% (mycelial yield and IPS) were found to be a suitable condition for submerged culture.

Dry mycelium of Penicillium chrysogenum induces expression of pathogenesis-related protein genes and resistance against wilt diseases in Bt transgenic cotton

Dry mycelium (DM) of Penicillium chrysogenum (PEN), a waste product of the pharmaceutical industry, is used as an organic fertilizer for agricultural production. Our previous studies have indicated that DM of PEN is effective in controlling a number of soil born fungal diseases, but the mode of action is unclear. In the present study, DM of PEN was extracted with water and applied to the roots of the Bt (Bacillus thuringiensis) transgenic cotton (Gossypium hirsutum) cultivar SCRC 21. The efficacy in controlling Fusarium oxysporum f.sp vasinfectum (Fov) and Verticillium dahliae Kleb (Vd), as well as the accumulation of pathogenesis-related (PR) protein transcripts in the plants were examined. The results showed that soil drench with PEN provided significant protection against Fov and Vd. The controlling efficacy of PEN was dose-dependent, and the highest efficacy was obtained with 5–7% PEN. Soil drench with 5% induced the accumulation of six PR protein transcripts, PR-1a, PR-1b, PR-2, PR-3, A-C and B-C in cotyledons of cotton seedlings, suggesting that these PR proteins may be involved in induced resistance against wilt diseases in cotton by PEN. It seems that DM of PEN represents a new agent capable of inducing both resistance and the accumulation of PR protein transcripts.

Kinetic resolution of ( R, S)-1,2- O-isopropylideneglycerol by esterification with dry mycelia of moulds

The esterification of ( R, S)-1,2- O-isopropylideneglycerol catalysed by dry mycelia of different moulds in organic solvent was studied. Dry mycelium of Rhizopus oryzae CBS 112.07 and Aspergillus oryzae MIM gave the ( R)-ester with moderate optical purity; the kinetic data of the esterification with butyric acid in n-heptane showed an enantiomeric ratio of 3.4 with Rhizopus oryzae and 8.0 with Aspergillus oryzae. The esterification catalysed by Aspergillus oryzae was performed on larger scale (operative volume 2.3 l) allowing for the production of 2.3 g l −1 of ( R)-IPG butyrate with an e.e. = 56% and a molar conversion of 52%. The enantiomerically enriched ester was hydrolysed with thermally-treated cells of Bacillus coagulans: the ( S)-ester was obtained as enantiomerically pure molecule, while the alcohol was recovered with e.e. = 90%.

Identification and production of n−8 odd‐numbered polyunsaturated fatty acids by a Δ12 desaturation‐defective mutant of Mortierella alpina 1S‐4

A mutant of Mortierella alpina, JT-180, which is defective in its delta12 desaturase activity but exhibits enhanced activities of delta5 and delta6 desaturases, produced a high proportion (up to 80%) of odd-chain FA when grown on 3% n-heptadecane. Following growth of the mutant on n-heptadecane, three unusual odd-chain fatty acyl residues were identified as 6,9-heptadecadienoic acid (17:2), 8,11 -nonadecadienoic acid (19:2), and 5,8,11-nonadecatrienoic acid (19:3) by means of GC-MS, MS-MS, and NMR analyses. The mycelial contents of these FA reached 20.3, 3.6, and 5.8 mg/g dry mycelia, respectively, when it was cultivated in medium comprising 4% (vol/vol) n-heptadecane and 1% (wt/vol) yeast extract, pH 6.0, at 28 degrees C for 7 d. The biosynthetic route (n-8 route) to 19:3 was presumed to mimic the n-9 route to Mead acid (20:3n-9) in mammals: 17:0 --> 9-17:1 --> 6,9-17:2 --> 8,11-19:2 --> 5,8,11-19:3.

An Aqueous Extract of the Dry Mycelium of Penicillium chrysogenum Induces Resistance in Several Crops under Controlled and Field Conditions

We have examined the effect of Pen, an aqueous extract of the dry mycelium of Penicillium chrysogenum, on plant–pathogen interactions. Pen controlled a broad range of pathogens on several crop plants under greenhouse and field conditions. Pen protected grapevine from downy and powdery mildew (caused by Plasmopara viticola and Uncinula necator), tomato from early blight (caused by Phytophthora infestans), onion from downy mildew (Peronospora destructor) and apple trees from apple scab (caused by Venturia inaequalis) to a similar extent as fungicides such as copper and sulphur or well-known inducers such as benzothiadiazole or β-aminobutyric acid. Pen had no major direct fungicidal effect and is thus supposed to protect plants by activating their defense mechanisms. The raw material for extraction of Pen was available in constant quality, a prerequisite for commercial application. Under certain conditions, Pen caused phytotoxic side effects. The symptoms mostly consisted of small necrotic spots or, more rarely, of larger necrotic areas. The development of the symptoms was dependent on several parameters, including concentration of Pen, the number of applications, the persistence on the plant tissue, the plant species and variety and environmental conditions. In grapevine, a partially purified fraction of Pen was much less toxic than the crude Pen extract, but protected the plants to a similar extent against P. viticola. Our data show that Pen has interesting and unique properties as a plant protection agent, but more research is needed to further reduce its phytotoxic side effects.

Comparison of Sclerotinia Minor Inocula for differentiating the Reaction of Peanut genotypes to Sclerotinia Blight

Abstract Efficacy of four types of Sclerotinia minor inocula were compared for disease incidence, lesion development, and differentiating a disease response on susceptible and moderately resistant peanut genotypes. Inocula were evaluated on intact and detached peanut main stem tissue. Three inocula lacked an exogenous nutrient source, which included germinating sclerotia produced on peanut stem, 3-day-old dry mycelia, and perlite granules coated with fresh mycelial fragments. Inoculum with an exogenous nutrient source consisted of an agar plug with mycelium. The mycelial agar plug inoculum resulted in a greater disease incidence and a longer mean lesion length/day compared to other inocula on intact stem or detached stem tissue. All inocula produced longer (P < 0.05) lesions 6 d after inoculation on intact stem tissue for susceptible control and shorter lesions on three of the four moderately resistant genotypes. All inocula produced longer (P < 0.05) lesions 6 d after inoculation on detached stem tissue ...

Dry mycelium of Penicillium chrysogenum protects cotton plants against wilt diseases and increases yield under field conditions

Previous studies have indicated that dry mycelium (DM) of Penicillium chrysogenum ( PEN), a waste product of the pharmaceutical industry, is effective in controlling fungal diseases in crop plants under greenhouse or shade-house conditions. In the present study, cotton was grown in fields amended with DM before planting, or squaring, or both, in Linqing and Liaocheng, Shandong province, China, and disease severity of Fusarium oxysporum f.sp vasinfectum ( Fov) and Verticillium dahliae ( Vd) was monitored from 2001 to 2004. Results from the first experiment in 2001 and 2002 showed that DM was effective in protecting, in an application mode-dependent manner, against these two pathogens. At a dose of 30 g m −2, either basal application alone or basal application plus side dressing of DM provided significant protection against Fusarium wilt and Verticillium wilt, but side dressing alone was not significantly effective in controlling the two diseases. In the second experiment in 2003 and 2004, it was shown that disease-control efficacy of DM was dependent on application rates. Averaged across two sites and both years (2003 and 2004), basal application plus side dressing at doses of 30, 90 and 150 g m −2 provided protection of 20.1, 34.6 and 42.7% against Fov, and of 26.8, 47.8 and 49.6% against Vd, respectively, compared to their corresponding DM-free controls. Increases in lint yield of cotton was also obtained by application of DM each year, which could be attributed to both disease control and nutritional effects of DM. DM (⩽2%) had no effect on mycelial growth of the pathogens in vitro, suggesting that the protection was probably attributable to induced resistance. It is concluded that DM of PEN may serve as an organic product for both disease control and plant nutrition in cotton production.

Newly isolated Streptomyces spp. as enantioselective biocatalysts: hydrolysis of 1,2-O-isopropylidene glycerol racemic esters

To identify microbial strains with esterase activity able to enantioselectively hydrolyse esters of (R,S)-1,2-O-isopropylidene glycerol. The microbial hydrolysis of various racemic esters of 1,2-O-isopropylidene glycerol (IPG) was attempted by screening among Streptomyces spp. previously selected on the basis of their carboxylesterase activity. The best results were observed in the hydrolysis of butyrate ester and two strains appeared promising as they showed opposite enantioselectivity: Streptomyces sp. 90852 gave predominantly (S)-IPG, while strain 90930 mostly gave the R-alcohol. Streptomyces sp. 90930 was identified as Streptomyces violaceusniger, whereas Streptomyces sp. 90852 is a new species belonging to the Streptomyces violaceus taxon. The carboxylesterase belonging to strain 90852 gave a maximum value of enantiomeric ratio (E) of 14-16. This strain was lyophilized and used as dry mycelium for catalysing the synthesis of isopropylidene glycerol butyrate in heptane showing reaction rate and enantioselectivity (E = 6.6) lower than what observed for the hydrolysis. A new esterase with enantioselective activity towards (R,S)-IPG butyrate has been selected. The best enantioselectivity is similar or even better than the highest reported value in the literature with commercial enzymes. The enzyme is produced by a new species belonging to the S. violaceus taxon. New esterases from streptomycetes can be employed for the enantioselective hydrolysis of chiral esters derived from primary alcohols, not efficiently resolved with commercial enzymes.

The effect of media, oil type and rate on the mycelia wet and dry weights of Lentinus squarrosulus (Mont.) singer and psathyrella patroumbonata pegler in submerged liquid culture

Lentinus squarrosulus and Psathyrella atroumbonata, two edible indigenous mushroom species, were cultured in four different submerged liquid media supplemented with coconut, cotton, groundnut, butterfat, palm kernel and palm oil at 5 different rates. The differences in the means due to the different media types were highly significant (p<0.01) for the mean mycelia wet and dry weights of bothL. squarrosulus and P. atroumbonata. SLCM3, which contained twice the glucose level present in each of the other three liquid culture media, induced the heaviest mean wet and dry mycelia weights of both mushroom species. Oil type had a highly significant (p<0.01) effect on the wet and dry mycelia weights of L. squarrosulus as well as the mycelia wet weight of P. atroumbonata. Butterfat induced the heaviest weights. In addition, oil rate also had a significant effect (p<0.01) on the mean mycelia wet and dry weights of both mushroom species. The oil rates of 0.003, 0.005 and 0.007 ml/ml produced comparable optimum mean mycelia wet and dry weights of the mushrooms. Key words: Lentinus squarrosulus, Psathyrella atroumbonata, supplemented media, submerged liquid media, oil type and rate.

Enhanced production of manganese peroxidase from immobilized Phanerochaete chrysosporium due to the increased autolysis of chlamydospore-like cells

The autolysis of chlamydospore-like cells in Phanerochaete chrysosporium immobilized in polyurethane foam correlated with the production of manganese peroxidase (MnP). The maximum specific activity of MnP was 1055 U g dry mycelium(-1) in the immobilized culture, compared with 260 U g dry mycelium(-1) in the submerged culture. Scattered mycelial pellets were formed in the immobilized culture in which almost all of the chlamydospore-like cells were subject to autolysis. However, highly crowded pellets were formed in the free culture, in which only the chlamydospore-like cells in the exterior were subject to autolysis. We propose that the enhanced production of MnP in immobilized cultures of P. chrysosporium is due to increased autolysis of the chlamydospore-like cells.

Lead and cadmium uptake in the marine fungi Corollospora lacera and Monodictys pelagica

This study provides observations on the effects of lead and cadmium ions on the growth of two species of marine fungi, Corollospora lacera and Monodictys pelagica. On solid media lead appeared to have no effect on the radial rate of growth of fungi. Exposure to increasing cadmium concentrations on solid media resulted in significant reduction ( p < 0.05) in the radial mycelial growth rates of both fungi, especially in M. pelagica. These results reveal significant difference in species sensitivity toward cadmium and, essentially, insensitivity toward lead exposure. In liquid cultures, the metal content of mycelia (metal mass found in mycelium, in mg), and the concentration of metal in dry mycelium (metal mass in 1 g of mycelium, in mg g −1) were both found to increase ( p < 0.05) with the increase in the metal cation concentration, while mycelium dry mass decreased. As it was observed on solid media, cadmium cation affected more severely ( p < 0.05) the growth of M. pelagica in liquid cultures. Ergosterol content of mycelia of C. lacera exposed to increasing cadmium cation concentration decreased, similarly to the trend observed for dry mycelial mass. It was found that ca. 93% of all lead sequestered by C. lacera is located extracellularly. M. pelagica was found to bioaccumulate over 60 mg of cadmium and over 6 mg of lead per 1 g of mycelium, while C. lacera bioaccumulated over 7 mg of cadmium and up to 250 mg of lead per 1 g of mycelium. Overall, the results indicate that both metal ions affect the growth of marine fungi with lead being accumulated extracellularly in the mycelia. Both metals accumulated by fungi may then enter the marine ecosystem food web, of which marine fungi are integral members.