Fomitopsis betulina (formerly Piptoporus betulinus): the Iceman's polypore fungus with modern biotechnological potential.

Higher Basidiomycota have been used in natural medicine throughout the world for centuries. One of such fungi is Fomitopsis betulina (formerly Piptoporus betulinus), which causes brown rot of birch wood. Annual white to brownish fruiting bodies of the species can be found on trees in the northern hemisphere but F. betulina can also be cultured as a mycelium and fruiting body. The fungus has a long tradition of being applied in folk medicine as an antimicrobial, anticancer, and anti-inflammatory agent. Probably due to the curative properties, pieces of its fruiting body were carried by Ötzi the Iceman. Modern research confirms the health-promoting benefits of F. betulina. Pharmacological studies have provided evidence supporting the antibacterial, anti-parasitic, antiviral, anti-inflammatory, anticancer, neuroprotective, and immunomodulating activities of F. betulina preparations. Biologically active compounds such as triterpenoids have been isolated. The mushroom is also a reservoir of valuable enzymes and other substances such as cell wall (1→3)-α-D-glucan which can be used for induction of microbial enzymes degrading cariogenic dental biofilm. In conclusion, F. betulina can be considered as a promising source for the development of new products for healthcare and other biotechnological uses.

(1→3)-α-D-Glucan hydrolases in dental biofilm prevention and control: A review.

Dental plaque is a highly diverse biofilm, which has an important function in maintenance of oral and systemic health but in some conditions becomes a cause of oral diseases. In addition to mechanical plaque removal, current methods of dental plaque control involve the use of chemical agents against biofilm pathogens, which however, given the complexity of the oral microbiome, is not sufficiently effective. Hence, there is a need for development of new anti-biofilm approaches. Polysaccharides, especially (1→3),(1→6)-α-D-glucans, which are key structural and functional constituents of the biofilm matrix, seem to be a good target for future therapeutic strategies. In this review, we have focused on (1→3)-α-glucanases, which can limit the cariogenic properties of the dental plaque extracellular polysaccharides. These enzymes are not widely known and have not been exhaustively described in literature.

The influence of aqueous extracts of selected Potentilla species on normal human colon cells.

Potentilla L. (Rosaceae) species have been used in traditional medicine in Asia, Europe and Northern America. This study analyzed the biological activity of aqueous extracts of Potentilla species (Rosaceae): Dasiphora fruticosa (syn. P. fruticosa), P. norvegica, P. pensylvanica, P. thuringiaca, P. crantzii and P. nepalensis. The activities were tested using MTT, NR and DPPH assays on normal human colon epithelium (CCD 841 CoTr) and colon myofibroblast (CCD-18Co) cells. Moreover, cell morphology using the May-Grünwald-Giemsa method, IL-6 by ELISA, and nitric oxide (NO) analysis with the Griess method in culture supernatants were performed after 24 h. Extracts were tested at dose levels between 25 and 250 microg/mL. For ELISA, 15 microg/mL was chosen. All extracts suppressed the metabolism of myofibroblasts, while epithelial cells' mitochondrial dehydrogenase activity decreased after incubation with extracts. All extracts showed a free radical scavenging (DPPH) effect in a concentration-dependent manner. The most potent was the extract from D. fruticosa, while the least action was observed for P. thuringiaca. Potentilla extracts stimulated, IL-6 production in tested cells but the level of the cytokine was found to decrease in epithelial cells. Pre-incubation of cells with LPS resulted in increased IL-6 secretion. Modulation of NO production after extract addition and cell pre-incubation with LPS was also observed. Potentilla extracts may be interesting natural factors modulating the main features of cells forming the colon wall, and thus may be potentially useful in the prophylaxis or healing of colon disorders.

Water-soluble (1→3),(1→4)-α-D-glucan from mango as a novel inducer of cariogenic biofilm-degrading enzyme.

A water-soluble polysaccharide (WSP) extracted from mango (Mangifera indica L.) fruits has been suggested as a new alternative to mutan for mutanase induction in Trichoderma harzianum. Structural analyses revealed that the purified WSP was a (1→3),(1→4)-α-D-glucan with the molecular mass of ca. 760 kDa in which the (1→4)-linked and (1→3)-linked α-Glcp residues were in a ratio of 1:2.4. When the strain T harzianum CCM F-340 was grown in the presence of WSP, the maximal enzyme productivity obtained after 3 days of cultivation was 34 mU/mL. The mango WSP proved to be a very effective stimulus of mutanase expression giving a 5.1-fold higher than without WSP, transcription. It was shown that the mixture of WSP-induced mutanase and commercial dextranase had a high hydrolytic potential in the reaction with streptococcal mutan, where maximal degrees of solubilization and saccharification of this biopolymer (93.4% and 80%, respectively) were reached within 9h (solubilization) and 24h (saccharification). The mixed enzymatic preparation was also effective in degradation of streptococcal mutan and its removal from cariogenic biofilms. After 3h hydrolysis, only 18.2% of the biofilm remained adhered to the glass surface.

Effects of culture conditions on production of extracellular laccase by Rhizoctonia praticola.

It was found that the soil-dwelling fungus Rhizoctonia praticola 93A was capable to produce laccase in submerged cultures. Effects of culture conditions on the enzyme biosynthesis in shaken flask and aerated bioreactor cultures were evaluated to improve the yields of the process. Production of extracellular laccase was considerably intensified by the addition of Cu2+ to a carbon-limited and nitrogen-sufficient culture medium (C/N = 0.98). When an optimized medium containing glucose (2 g/l) and L-asparagine (1.5 g/l) was used and enzyme synthesis was stimulated by addition of 5 microM Cu2+ before inoculation, maximal laccase activities obtained in a batch cultivation were, approximately, 1000 nkat/l. Under these conditions, addition to the medium of the aromatic inducer 2,5-xylidine (1 mM) led to a 10-fold increase in laccase activity. Laccase productivity in shaken flask cultures was also enhanced (to more than 4000 nkat/l on day 3) by using a medium with the initial pH of 7.5. Such a high value of the optimal medium pH for laccase production by R. praticola is exceptional among the ligninolytic fungi. In fermenter fungal cultures supplemented with cupric ions, the highest laccase activity (about 4000 nkat/l after 3 days' cultivation) was reached after 24-h incubation using a bioreactor with the aeration rate of 21/min, the agitation speed of 200 rpm, and a constant medium pH of 8.0.