POLYOLS IN SCHIZOPHYLLUM COMMUNE

Sugars and sugar alcohols present in extracts of the wood-rotting mushroom Schizophyllum commune were identified by paper chromatography during fruiting, basidiospore germination, and growth of vegetative mycelium. Homokaryotic fruitbodies and dikaryotic fruits derived from several compatible matings of S. commune contained mannitol and arabitol. Basidiospores shed from dikaryotic fruits also contained mannitol and arabitol while the latter disappeared during spore germination. Vegetative mycelium (strain 699) contained glucose, fructose, mannitol and glycerol while these compounds as well as arabitol occurred in mycelium of strain 845. Polyols are not, therefore, associated exclusively with the sporulation process in S. commune.     

The mycelial response of the white-rot fungus, Schizophyllum commune to the biocontrol agent, Trichoderma viride

In this study, agar plate interaction between Schizophyllum commune and Trichoderma viride was investigated to characterise the physiological responses occurring during interspecific mycelial combat. The metabolite profiles and morphological changes in both fungi paired on agar were studied relative to the modulation of phenoloxidase activity in S. commune. The calcium ionophore A23187 was incorporated in self-paired cultures of S. commune to explore possible involvement of calcium influx in the response of S. commune to T. viride. The levels of lipid peroxides and protein carbonyls in the confronted mycelia of S. commune were also measured. Contact with T. viride induced pigmentation and cell wall hydrolysis in S. commune with concomitant increase in phenoloxidase activity, rise in the levels of oxidative stress indicators and increased levels of phenolic compounds, antioxidant γ-amino butyric acid, and pyridoxine and osmo-protective sugar alcohols. Calcium ionophore mimicked the pigmentation in the T. viride-confronted mycelia of S. commune, implicating calcium influx in the response to T. viride. The changes in S. commune are indicative of targeted responses to osmotic and oxidative stresses and phenoloxidase-mediated detoxification of noxious compounds in the contact interface with T. viride, which may confer resistance in natural environments.     

Enhanced decolorization of Solar brilliant red 80 textile dye by an indigenous white rot fungus Schizophyllum commune IBL-06

An indigenously isolated white rot fungus, Schizophyllum commune IBL-06 was used to decolorize Solar brilliant red 80 direct dye in Kirk’s basal salts medium. In initial screening study, the maximum decolorization (84.8%) of Solar brilliant red 80 was achieved in 7 days shaking incubation period at pH 4.5 and 30 °C. Different physical and nutritional factors including pH, temperature and fungal inoculum density were statistically optimized through Completely Randomized Design (CRD), to enhance the efficiency of S. commune IBL-06 for maximum decolorization of Solar brilliant red 80 dye. The effects of inexpensive carbon and nitrogen sources were also investigated. Percent dye decolorization was determined by a reduction in optical density at the wavelength of maximum absorbance (λ_max, 590 nm). Under optimum conditions, the S. commune IBL-06 completely decolorized (100%) the Solar brilliant red 80 dye using maltose and ammonium sulfate as inexpensive carbon and nitrogen sources, respectively in 3 days. S. commune IBL-06 produced the three major ligninolytic enzymes lignin peroxidase (LiP), manganase peroxidase (MnP) and lacaase (Lac) during the decolorization of Solar brilliant red 80. LiP was the major enzyme (944 U/mL) secreted by S. commune IBL-06 along with comparatively lower activities of MnP and Laccase.     

Identification of Long Non-Coding RNAs and Their Target Genes from Mycelium and Primordium in Model Mushroom Schizophyllum commune

Schizophyllum commune has emerged as the most promising model mushroom to study developmental stages (mycelium, primordium), which are two primary processes of fruit body development. Long non-coding RNA (lncRNA) has been proved to participate in fruit development and sex differentiation in fungi. However, potential lncRNAs have not been identified in S. commune from mycelium to primordium developmental stages. In this study, lncRNA-seq was performed in S. commune and 61.56 Gb clean data were generated from mycelium and primordium developmental stages. Furthermore, 191 lncRNAs had been obtained and a total of 49 lncRNAs were classified as differently expressed lncRNAs. Additionally, 26 up-regulated differently expressed lncRNAs and 23 down-regulated between mycelium and primordia libraries were detected. Further, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that differentially expressed lncRNAs target genes from the MAPK pathway, phosphatidylinositol signal, ubiquitin-mediated proteolysis, autophagy, and cell cycle. This study provides a new resource for further research on the relationship between lncRNA and two developmental stages (mycelium, primordium) in S. commune.     

Organic Acid Production by Basidiomycetes: I. Screening of Acid-Producing Strains

Sixty-seven strains belonging to 47 species of Basidiomycetes were examined for their acid-producing abilities in glucose media, in both the presence and absence of CaCO₃, in stationary and shake cultures. Some strains were found to produce large quantities of oxalic acid. The oxalic acid-producing strains could be separated into two groups. Strains of one group (mostly brown-rot fungi) were able to produce oxalic acid, regardless of whether CaCO₃ was present in the medium. Strains of the other group (mostly white-rot fungi) were characterized by their ability to produce oxalic acid only when CaCO₃ was added to the medium. With the latter group, shake-culturing was generally more effective than stationary culturing in respect to acid production. In the CaCO₃-containing media, Schizophyllum commune, Merulius tremellosus, and Porodisculus pendulus were found to produce substantial amounts of L-malic acid as a main metabolic product, along with small quantities of oxalic and other acids in shake cultures. Especially, S. commune and M. tremellosus may be employed as malic acid-producing species.     

Identification and characterization of Schizophyllum commune type I metacaspases

The role of programmed cell death in filamentous fungi is not well-understood, but is important due to the role of fungi in opportunistic infections. Plants, fungi and protozoa do not have caspase genes, but instead express the homologous proteins denoted metacaspases. To better understand the role of metacaspases in fungi we present an analysis of the sequences and activities of all five Type I metacaspases from Schizophyllum commune (ScMC), a mushroom-forming basiodmycete that undergoes sexual reproduction. The five Type I metacaspases of S. commune can be divided into two groups based on sequence similarity. Enzymes both with and without the N-terminal prodomain are active, but here we report on the constructs without the prodomains (Δpro). All five ScMCΔpro proteins show the highest enzymatic activity between pH 7 and 8 and require calcium for optimal activity. Optimal Ca²⁺ concentrations for ScMC1Δpro and ScMC2Δpro are 50 mM, while ScMC3, ScMC4Δpro and ScMC5Δpro activity is optimal around 5 mM calcium. All five S. commune metacaspases have similar substrate specificity. They are most active with Arg in the P1 position and inactive with Asp in the P1 position.     

Schizophillum commune Causing Sinusitis with Nasal Polyposis in the Sub-Himalayan Region: First Case Report and Review

Schizophillum commune is an environmental fungus rarely causing human infections of diverse nature. Sinusitis occurs in immunocompromised persons and seldom in healthy subjects. Though easily isolated, the lack of awareness of its virulence is a bottleneck in the diagnosis of this infection. We report the first case of S. commune sinusitis with nasal polyps in an immunocompetent male from the sub-Himalayan region. The computerized tomography scan findings established the clinical diagnosis, and causative agent was confirmed as S. commune. A white, woolly mold with septate, hyaline hyphae and characteristic spicules but unclamped connections suggested a monokaryotic isolate. Patient was treated successfully with fiberoptic endoscopic sinus surgery, and no antifungal therapy was instituted. There was no recurrence at review after 1 year.     

Isolation and in silico analysis of Fe-superoxide dismutase in the cyanobacterium Nostoc commune

Cyanobacteria are known to endure various stress conditions due to the inbuilt potential for oxidative stress alleviation owing to the presence of an array of antioxidants. The present study shows that Antarctic cyanobacterium Nostoc commune possesses two antioxidative enzymes viz., superoxide dismutase (SOD) and catalase that jointly cope with environmental stresses prevailing at its natural habitat. Native-PAGE analysis illustrates the presence of a single prominent isoform recognized as Fe-SOD and three distinct isoforms of catalase. The protein sequence of Fe-SOD in N. commune retrieved from NCBI protein sequence database was used for in silico analysis. 3D structure of N. commune was predicted by comparative modeling using MODELLER 9v11. Further, this model was validated for its quality by Ramachandran plot, ERRAT, Verify 3D and ProSA-web which revealed good structure quality of the model. Multiple sequence alignment showed high conservation in N and C-terminal domain regions along with all metal binding positions in Fe-SOD which were also found to be highly conserved in all 28 cyanobacterial species under study, including N. commune. In silico prediction of isoelectric point and molecular weight of Fe-SOD was found to be 5.48 and 22,342.98 Da respectively. The phylogenetic tree revealed that among 28 cyanobacterial species, Fe-SOD in N. commune was the closest evolutionary homolog of Fe-SOD in Nostoc punctiforme as evident by strong bootstrap value. Thus, N. commune may serve as a good biological model for studies related to survival of life under extreme conditions prevailing at the Antarctic region. Moreover cyanobacteria may be exploited for biochemical and biotechnological applications of enzymatic antioxidants.     

High Production of β-Glucosidase in Schizophyllum commune: Isolation of the Enzyme and Effect of the Culture Filtrate on Cellulose Hydrolysis

Optimization experiments with response surface statistical analysis were performed with Schizophyllum commune to obtain high β-glucosidase yields. The factors in the optimization experiment were the concentrations of cellulose, peptone, and KH₂PO₄. Their optimal values were 3.2, 3.0, and 0.2 g/100 ml, respectively. Enzyme assays revealed very high β-glucosidase (22.2 U/ml) and cellobiase (68.9 U/ml) yields. The avicelase yield was low as compared with that from Trichoderma reesei. Mixtures of S. commune and T. reesei culture filtrates caused faster and more extensive saccharification of Avicel than could be achieved by either filtrate alone. A β-glucosidase was isolated and purified from the optimized culture filtrate of S. commune. The electrophoretic mobility of the purified β-glucosidase indicated a molecular weight of 97,000. The amino acid composition was similar to that of β-glucosidase from T. reesei. The acidic (aspartate and glutamate) residues or their amides or both made up approximately 20% of the protein. The NH₂-terminal amino acid of the enzyme was histidine.     

Rice straw fermentation by Schizophyllum commune ARC-11 to produce high level of xylanase for its application in pre-bleaching

Rice straw is valuable resource that has been used as substrate for cost effective production of xylanase under solid-state fermentation by a newly isolated white rot fungi, S. commune ARC-11. Out of eleven carbon sources tested, rice straw was found most effective for the induction of xylanase that produced 4288.3?IU/gds of xylanase by S. commune ARC-11. Maximum xylanase production (6721.9?IU/gds) was observed on 8^th day of incubation at temperature (30?°C), initial pH (7.0) and initial moisture content (70.0%). The supplementation of ammonium sulphate (0.08% N, as available nitrogen) enhanced the xylanase production up to 8591.4?IU/gds. The xylanase production by S. commune ARC-11 was further improved by the addition of 0.10%, (w/v) of Tween-20 as surfactant. The maximum xylanase activities were found at pH 5.0 and temperature 55?°C with a longer stability (180?min) at temperature 45, 50 and 55?°C. This xylanase preparation was also evaluated for the pre-bleaching of ethanol-soda pulp from Eulaliopsis binata. An enzyme dosage of 10?IU/g of xylanase resulted maximum decrease in kappa number (14.51%) with a maximum improvement 2.9% in ISO brightness compared to control.     

Protective antifungal effect of neem (Azadirachta indica) extracts on mango (Mangifera indica) and rain tree (Albizia saman) wood

Neem (Azadirachta indica) extract (NE) and NE combined with copper sulfate and boric acid (NECB) were examined for their protective effect against fungal deterioration of mango (Mangifera indica) and rain tree (Albizia saman) wood. Growth of the white-rot fungus Schizophyllum commune was completely inhibited on solid medium containing 1.8% (w/w) NE or 5% (w/w) NECB. The average weight losses of NE and NECB treated wood blocks inoculated with S. commune were respectively 4.7% and 3.3% for M. indica and 4.1% and 3.0% for A. saman. These numbers were significantly lower compared to those obtained in the untreated condition. Similar observations were also noticed in the case of field tests. An average increase of life span of M. indica and A. saman due to NE treatment compared to untreated samples was about 6–7 times higher. Therefore, both NE and NECB treatments are promising preservation options for enhancing the durability of both M. indica and A. saman woods.     

COBALT AS A MITOCHONDRIAL DENSITY MARKER IN A STUDY OF CYTOPLASMIC EXCHANGE DURING MATING OF SCHIZOPHYLLUM COMMUNE

A slow in vivo uptake of cobalt from a growth medium resulted in an increase in density of mitochondria of Schizophyllum commune. Differential labeling of donor and resident mycelia, and subsequent analysis of resident mycelia surrounding donor implants, detected cobalt-dense mitochondria and demonstrated exchange of mitochondria after hyphal fusion. Transfer of mitochondria occurred in fully compatible, common-A, and common-AB matings, but was not detected in common-B matings of the tetrapolar Basidiomycete S. commune.     

Schizophyllum commune: A New Organism in Eye Infection

Purpose

We report a case of mycotic keratitis caused by a rare fungus Schizophyllum commune.

Methods

Clinical examination, slit-lamp examination, and microbiological evaluation of the corneal ulcer were done, and its treatment outcome was studied. The fungal etiology was established by conventional microbiological techniques, polymerase chain reaction and speciation by DNA sequencing.

Results

Corneal scraping showed the presence of fungal filaments. The fungus was identified as S. commune based on DNA sequence analysis of the internal transcribed spacer region. The organism was susceptible to amphotericin B and voriconazole and demonstrated resistance to anidulafungin, itraconazole, and fluconazole. Therapeutic keratoplasty was performed but there was recurrence of the infection in the graft, which was controlled with topical voriconazole and intracameral amphotericin B. At the end of 3 months, the affected eye had developed phthisis bulbi.

Conclusion

The best of our knowledge, this is the first reported case of keratitis caused by the rare fungus S. commune. Management of these cases is difficult, and surgical procedures may be needed.     

RNA-Mediated Gene Silencing in Monokaryons and Dikaryons of Schizophyllum commune

Disruption of genes by homologous recombination occurs at a low frequency in the basidiomycete Schizophyllum commune. For instance, the SC3 and SC15 genes were inactivated at frequencies of 1 and 5%, respectively. As an alternative to disruption, we used gene silencing through the introduction of a hairpin construct. The SC15 gene, which encodes an abundantly secreted structural protein, was silenced at a frequency of 80% in monokaryons of S. commune after introduction of a hairpin construct of the gene. Silencing also occurred in dikaryons in which one of the partners was not a silenced strain. The silencing mechanism resembles RNAi in other filamentous fungi and is a powerful tool for the functional analysis of genes expressed in monokaryons or dikaryons.     

Production of extracellular β-1,3-/β-1,6-glucan by mono- and dikaryons ofSchizophyllum commune

From the dikaryotic mycelium ofSchizophyllum commune ATCC 38548 several monokaryotic strains were obtained by isolating the two types of monokaryotic protoplasts and their reversion to hyphal growth. The dikaryoticS. commune ATCC 38548 produced about 10 g/liter of extracellular β-1,3-/β-1,6-glucan (schizophyllan) after 96 h of growth, while the monokaryons excreted much less of this polysaccharide. During growth of strains of both types of monokaryons indigo and β-1,3-glucanase activities were excreted. Two selected monokaryons were mated with other monokaryoticS. commune strains and some of the dikaryotic mycelia obtained produced about 12 g/liter of extracellular β-1,3-/β-1,6-glucan after 120 h of cultivation.     

Effects of fermenter type,xylanase addition and dual cultures on fungal fermentations of wheat pollard and bran

Pollard and bran were fermented by a selection of filamentous fungi to increase the protein content and availability for use as animal feed. Aspergillus terreus produced a product containing 32·6% crude protein (CP) after 16 days. Under identical environmental conditions, shallow-layer solid-state fermentations achieved higher CP yields than did tumbled or packed-column systems. When crude xylanase was added with A. terreus inoculum, a 5-day reduction in fermentation time was achieved resulting in a maximum CP content of 27%. A. terreus, Chaetomium virescens, Schizophyllum commune or Trichoderma reesei, in dual culture with one another or in combination with Phanerochaete chrysosporium, did not achieve higher final CP yields (after 16 days) than A. terreus alone. P. chrysosporium in combination with T. reesei and with S. commune resulted in the most rapid CP development of 26·1% and 26·4%, respectively, during the first 10 days.