Modified polymeric biomaterials with antimicrobial and immunomodulating properties

The modification of the surgical polypropylene mesh and the polytetrafluoroethylene vascular prosthesis with cecropin A (small peptide) and puromycin (aminonucleoside) yielded very stable preparations of modified biomaterials. The main emphasis was placed on analyses of their antimicrobial activity and potential immunomodulatory and non-cytotoxic properties towards the CCD841 CoTr model cell line. Cecropin A did not significantly affect the viability or proliferation of the CCD 841 CoTr cells, regardless of its soluble or immobilized form. In contrast, puromycin did not induce a significant decrease in the cell viability or proliferation in the immobilized form but significantly decreased cell viability and proliferation when administered in the soluble form. The covalent immobilization of these two molecules on the surface of biomaterials resulted in stable preparations that were able to inhibit the multiplication of Staphylococcus aureus and S. epidermidis strains. It was also found that the preparations induced the production of cytokines involved in antibacterial protection mechanisms and stimulated the immune response. The key regulator of this activity may be related to TLR4, a receptor recognizing bacterial LPS. In the present study, these factors were produced not only in the conditions of LPS stimulation but also in the absence of LPS, which indicates that cecropin A- and puromycin-modified biomaterials may upregulate pathways leading to humoral antibacterial immune response.

A New Exopolysaccharide from a Wood-Decaying Fungus Spongipellis borealis for a Wide Range of Biotechnological Applications

Fungi are a unique natural resource rich in polysaccharides, proteins, and other components. Polysaccharides are considered one of the most important bioactive components in fungi. Increasing numbers of studies have confirmed that fungal polysaccharides have various biological activities. Given these facts, the main aim of this investigation was to carry out isolation, identification, and structural characterisation of a new polysaccharide (EPS) derived from laboratory-cultured vegetative mycelium of a new Spongipellis borealis strain isolated from the environment. The examination of monosaccharides in the EPS demonstrated that the isolated biopolymer was composed mainly of glucose, galactose, and mannose monomers. The analysis of the methylation of the studied polymer indicated that it contained mainly terminal, →3)-linked, →4)-linked, and →2,4)-linked hexoses. The effect of fungal polysaccharides on S. borealis proteolytic enzymes (pepsin, trypsin, and pycnoporopepsin) and laccase activity was determined for the first time. Incubation of the enzyme preparation and EPS showed an influence of EPS on the stability of these enzymes, compared to the control values (without EPS).

Immobilisation of Cellobiose Dehydrogenase and Laccase on Chitosan Particles as a Multi-Enzymatic System for the Synthesis of Lactobionic Acid

Lactobionic acid (LBA) is a bioactive compound that has become increasingly popular in medicine in recent years due to its unique properties. This chemical can be formed via the enzymatic oxidation of lactose using fungal oxidoreductive enzymes. This study aimed to intensify the synthesis of LBA using immobilised enzymes (cellobiose dehydrogenase from Phanerochaete chrysosporium (PchCDH) and laccase from Cerrena unicolor (CuLAC)) on chitosan microspheres. We used three different crosslinking agents: genipin, glutaraldehyde, and polyethyleneimine to activate the chitosan. The FTIR and CellDrop techniques were used to characterise the activated microspheres. Quantitative (HPLC) and qualitative (TLC) methods were used to determine the obtained LBA. The results show that the type of activator used influences the efficiency of the binding of the enzyme to the matrix. Furthermore, the amount of LBA formed depends on the type of system used. The use of a system in which one of the enzymes is immobilised on a PEI-activated carrier (PchCDH) and the other is free (CuLAC) proved to be the most optimal, as it yielded almost 100% conversion of lactose to lactobionic acid. Summarising the data obtained the following: lactobionic acid immobilised on chitosan microspheres has great potential for medical applications.

Multi-Enzymatic Synthesis of Lactobionic Acid Using Wood-Degrading Enzymes Produced by White Rot Fungi

Enzymes produced by white rot fungi are involved in the synthesis of secondary metabolites with valuable biotechnological properties. One of these metabolites is lactobionic acid (LBA). The aim of this study was to characterize a novel enzyme system consisting of a cellobiose dehydrogenase from Phlebia lindtneri (PlCDH), a laccase from Cerrena unicolor (CuLAC), a redox mediator (ABTS or DCPIP), and lactose as a substrate. We used quantitative (HPLC) and qualitative methods (TLC, FTIR) to characterise the obtained LBA. The free radical scavenging effect of the synthesised LBA was assessed with the DPPH method. Bactericidal properties were tested against Gram-negative and Gram-positive bacteria. We obtained LBA in all the systems tested; however, the study showed that the temperature of 50 °C with the addition of ABTS was the most advantageous condition for the synthesis of lactobionic acid. A mixture with 13 mM LBA synthesised at 50 °C with DCPIP showed the best antioxidant properties (40% higher compared with the commercial reagent). Furthermore, LBA had an inhibitory effect on all the bacteria tested, but the effect was better against Gram-negative bacteria with growth inhibition no lower than 70%. Summarizing the obtained data, lactobionic acid derived in a multienzymatic system is a compound with great biotechnological potential.

Natural microbial polysaccharides as effective factors for modification of the catalytic properties of fungal cellobiose dehydrogenase

Polysaccharides are biopolymers composed of simple sugars like glucose, galactose, mannose, fructose, etc. The major natural sources for the production of polysaccharides include plants and microorganisms. In the present work, four bacterial and two fungal polysaccharides (PS or EPS) were used for the modification and preservation of Pycnoporus sanguineus cellobiose dehydrogenase (CDH) activity. It was found that the presence of polysaccharide preparations clearly enhanced the stability of cellobiose dehydrogenase compared to the control value (4 °C). The highest stabilization effect was observed for CDH modified with Rh110EPS. Changes in the optimum pH in the samples of CDH incubated with the chosen polysaccharide modifiers were evidenced as well. The most significant effect was observed for Rh24EPS and Cu139PS (pH 3.5). Cyclic voltammetry used for the analysis of electrochemical parameters of modified CDH showed the highest peak values after 30 days of incubation with polysaccharides at 4 °C. In summary, natural polysaccharides seem to be an effective biotechnological tool for the modification of CDH activity to increase the possibilities of its practical applications in many fields of industry.

Differences in Production, Composition, and Antioxidant Activities of Exopolymeric Substances (EPS) Obtained from Cultures of Endophytic Fusarium culmorum Strains with Different Effects on Cereals

Exopolymeric substances (EPS) can determine plant-microorganism interactions and have great potential as bioactive compounds. The different amounts of EPS obtained from cultures of three endophytic Fusarium culmorum strains with different aggressiveness-growth promoting (PGPF), deleterious (DRMO), and pathogenic towards cereal plants-depended on growth conditions. The EPS concentrations (under optimized culture conditions) were the lowest (0.2 g/L) in the PGPF, about three times higher in the DRMO, and five times higher in the pathogen culture. The EPS of these strains differed in the content of proteins, phenolic components, total sugars, glycosidic linkages, and sugar composition (glucose, mannose, galactose, and smaller quantities of arabinose, galactosamine, and glucosamine). The pathogen EPS exhibited the highest total sugar and mannose concentration. FTIR analysis confirmed the β configuration of the sugars. The EPS differed in the number and weight of polysaccharidic subfractions. The EPS of PGPF and DRMO had two subfractions and the pathogen EPS exhibited a subfraction with the lowest weight (5 kDa). The three EPS preparations (ethanol-precipitated EP, crude C, and proteolysed P) had antioxidant activity (particularly high for the EP-EPS soluble in high concentrations). The EP-EPS of the PGPF strain had the highest antioxidant activity, most likely associated with the highest content of phenolic compounds in this EPS.

Bacterial exopolysaccharides as a modern biotechnological tool for modification of fungal laccase properties and metal ion binding

Four bacterial EPSs extracted from Rhizobium leguminosarum bv. trifolii Rt24.2, Sinorhizobium meliloti Rm1021, Bradyrhizobium japonicum USDA110, and Bradyrhizobium elkanii USDA76 were determined towards their metal ion adsorption properties and possible modification of Cerrena unicolor laccase properties. The highest magnesium and iron ion-sorption capacity (~ 42 and ~ 14.5%, respectively) was observed for EPS isolated from B. japonicum USDA110. An evident influence of EPSs on the stability of laccase compared to the control values (without EPSs) was shown after 30-day incubation at 25 °C. The residual activity of laccases was obtained in the presence of Rh76EPS and Rh1021EPS, i.e., 49.5 and 41.5% of the initial catalytic activity, respectively. This result was confirmed by native PAGE electrophoresis. The EPS effect on laccase stability at different pH (from 3.8 to 7.0) was also estimated. The most significant changes at the optimum pH value (pH 5.8) was observed in samples of laccase stabilized by Rh76EPS and Rh1021EPS. Cyclic voltamperometry was used for analysis of electrochemical parameters of laccase stabilized by bacterial EPS and immobilized on single-walled carbon nanotubes (SWCNTs) with aryl residues. Laccases with Rh76EPS and Rh1021EPS had an evident shift of the value of the redox potential compared to the control without EPS addition. In conclusion, the results obtained in this work present a new potential use of bacterial EPSs as a metal-binding component and a modulator of laccase properties especially stability of enzyme activity, which can be a very effective tool in biotechnology and industrial applications.

Complex Biochemical Analysis of Fruiting Bodies from Newly Isolated Polish Flammulina velutipes Strains

The present study examined Polish strains of Flamulina velutipes as a potential source of nutraceuticals and found that their nutritional value is dependent on the fruiting bodies gathering time. To prove the above hypothesis protein, carbohydrate and phenolic substances concentration were determined. Moreover, catalase, superoxide dismutase, cellobiose dehydrogenase activities were assayed. In order to prove the healing properties of Enoki fruiting bodies the obtained extracts were tested for antioxidant and bacteriostatic abilities. We have proved that Polish F. velutipes fruiting bodies may be a rich source of antioxidants and that they are capable of inhibiting Staphylococcus aureus growth.

[Inhibitors of enzymes with potential medical applications]

From the earliest times, medicine has focused on finding the most suitable and effective treatment for every patient. At present, a dynamic development of diagnostic methods and techniques for designing new drugs allows to create therapies for many diseases at the molecular level. Among the many drugs appearing on the medical market every year, special attention should be paid to those whose action is based on the inhibition of proteolytic enzyme activity. Protease inhibitors are a diverse group of biologically active molecules for which antiviral, antimicrobial, antifungal, antiparasitic or anticancer effects have been documented. Successes in the treatment of HIV infection, hepatitis C and influenza diseases certainly encourage researchers to look for new inhibitors that could be used in new therapies. This paper provides an overview of selected information on enzyme inhibitors, especially protease inhibitors, which are already registered medicines and substances that are promising candidates for medical use.

The Influence of Biochemical Modification on the Properties of Adhesive Compounds

The main objective of this study was to determine the effect of biochemical modification of epoxy adhesive compounds on the mechanical properties of a cured adhesive exposed to various climatic factors. The epoxy adhesive was modified by lyophilized fungal metabolites and prepared by three methods. Additionally, the adhesive compound specimens were seasoned for two months at a temperature of 50 °C and 50% humidity in a climate test chamber, Espec SH 661. The tensile strength tests of the adhesive compounds were performed using a Zwick/Roell Z150 testing machine in compliance with the DIN EN ISO 527-1 standard. The examination of the adhesive specimens was performed using two microscopes: a LEO 912AB transmission electron microscope equipped with Quantax 200 for EDS X-ray spectroscopy and a Zeiss 510 META confocal microscope coupled to an AxioVert 200M. The experiments involved the use of a CT Skyscan 1172 tomograph. The results revealed that some mechanical properties of the modified adhesives were significantly affected by both the method of preparation of the adhesive compound and the content of the modifying agent. In addition, it was found that seasoning of the modified adhesives does not lead to a decrease in some of their mechanical properties.

Purification and characterization of laccase from Sinorhizobium meliloti and analysis of the lacc gene

The soil native bacterial strains were screened for laccase activity. Bacterial strain L3.8 with high laccase activity was identified as Sinorhizobium meliloti. The crude intracellular L3.8 enzyme extract was able to oxidize typical diagnostic substrates of plant and fungal laccases. Laccase L3.8 was purified 81-fold with a yield of 19.5%. The molecular mass of the purified bacterial laccase was found to be 70.0kDa and its pI was 4.77. UV-vis spectrum showed that L3.8 protein is a multicopper oxidase. The carbohydrate content of the purified enzyme was estimated at 3.2%. Moreover, the laccase active fraction was characterized in terms of kinetics, temperature, and pH optima as well as the effect of various chemical compounds on the laccase activity, and antioxidant properties, which indicated that the L3.8 laccase had unique properties that might be important in biotechnological applications. The lacc gene encoding S. meliloti laccase was cloned and characterized. The full-length sequence of 1950bp encoded a protein of 649 aa preceded by a signal peptide consisting of 26aa. Laccase L3.8 shared significant structural features characteristic of other laccases, including the conserved regions of four histidine-rich copper-binding sites. Potential biotechnological importance of a newly identified laccase is discussed.

Effect of exopolysaccharide from Ganoderma applanatum on the electrical properties of mouse fibroblast cells line L929 culture using an electric cell-substrate impedance sensing (ECIS) - Preliminary study

IIntroduction and objective. In recent years there has been intensified research on medicinal preparations of fungal origin. Some fungal polysaccharides may directly affect the inhibition of cancer cells proliferation which, stopping the cell cycle, leads to apoptosis. One of these substances (component of extract of Ganoderma spp) is extensively tested for its anti-cancer properties on the tumor cell lines. Electric cell-substrate impedance sensing (ECIS) is an in vitro impedance measuring system using alternating current (AC) to determinate the behaviour of the cells in physiological conditions.

OBJECTIVE

The aim of the study was to examine the electric properties (resistance, capacitance and impedance) of mouse fibroblasts cell line L929 after treatment by different concentration of crude exopolysaccharides from Ganoderma applanatum (GpEPS) in real time by ECIS technique.

MATERIALS AND METHODS

For the study, the L929 cell line culture was treated by different concentrations of GpEPS: C1=228.5 µg/mL; C2=22.85 µg/mL; C3=2.285 µg/mL; C4=0.2285 µg/mL; and C5=0.02285 µg/mL. Default optimal frequencies were used: Resistance (R) 4000Hz, Impedance (Z) 16000Hz, Capacitance (C) 64000Hz.

RESULTS

The study demonstrated that GpEPS had no significant effect on the resistance, capacitance and impedance cells cultures, which implies that there is no significant effect on the physiological processes of L929 fibroblasts. This indicates the possibility of using GpEPS preparation in anti-cancer therapy.

CONCLUSIONS

In the future, following further studies (comprising in preventive and therapeutic actions), GpEPS can be safely used in anti-cancer therapy which does not cause side-effects or damage to healthy cells.

Effect of different wavelengths of light on laccase, cellobiose dehydrogenase, and proteases produced by Cerrena unicolor, Pycnoporus sanguineus and Phlebia lindtneri

Three species of white rot fungi: Cerrena unicolor, Phlebia lindtneri and Pycnoporus sanguineus were cultured in two different media under five different lighting conditions: dark, white, red, blue, and green light. Laccase, cellobiose dehydrogenase, and protease activities were examined in the samples. Blue light efficiently boosted laccase synthesis in C. unicolor and P. sanguineus, whereas the highest activities (20 654 nkat/l) of P. lindtneri laccase were observed when this fungus was maintained in green light. On the contrary, the green light allowed obtaining the highest activities of cellobiose dehydrogenase of C. unicolor and P. lindtneri, while CDH of P. sanguineus seems to be dependent on white light. It is clearly visible that differences in protease activities are noticeable not only between the lights variants but also among the media used. However, high proteases activities are correlated with light variants inducing laccase in Lindeberg and Holm medium. Contrary to the cellulose-based medium, where they are weak in light variants that lead to high CDH activities.

Laccase purified from Cerrena unicolor exerts antitumor activity against leukemic cells

Chronic lymphocytic leukemia (CLL) is the most commonly observed adult hematological malignancy in Western countries. Despite the fact that recent improvements in CLL treatment have led to an increased percentage of complete remissions, CLL remains an incurable disease. Cerrena unicolor is a novel fungal source of highly active extracellular laccase (ex-LAC) that is currently used in industry. However, to the best of our knowledge, no reports regarding its anti-leukemic activity have been published thus far. In the present study, it was hypothesized that C. unicolor ex-LAC may possess cytotoxic activity against leukemic cell lines and CLL primary cells. C. unicolor ex-LAC was separated using anion exchange chromatography on diethylaminoethyl cellulose-Sepharose and Sephadex G-50 columns. The cytotoxic effects of ex-LAC upon 24- and 48-h treatment on HL-60, Jurkat, RPMI 8226 and K562 cell lines, as well as CLL primary cells of nine patients with CLL, were evaluated using 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay. Annexin V/propidium iodide staining of Jurkat cells treated with ex-LAC was used to investigate apoptosis via flow cytometry. Ex-LAC induced changes in Jurkat and RPMI 8226 cells, as visualized by fluorescence and scanning electron microscopy (SEM). The XTT assay revealed high cytotoxic rates following treatment with various concentrations of ex-LAC on all the cell lines and CLL primary cells analyzed, with a half maximal inhibitory concentration ranging from 0.4 to 1.1 µg/ml. Fluorescence microscopy and SEM observations additionally revealed apoptotic changes in Jurkat and RPMI 8226 cells treated with ex-LAC, compared with control cells. These results were in agreement with the apoptosis analysis of Jurkat cells on flow cytometry. In conclusion, C. unicolor ex-LAC was able to significantly induce cell apoptosis, and may represent a novel therapeutic agent for the treatment of various hematological neoplasms.

Extracellular polysaccharides from Ascomycota and Basidiomycota: production conditions, biochemical characteristics, and biological properties

Fungal polysaccharides (PSs) are the subject of research in many fields of science and industry. Many properties of PSs have already been confirmed and the list of postulated functions continues to grow. Fungal PSs are classified into different groups according to systematic affinity, structure (linear and branched), sugar composition (homo- and heteropolysaccharides), type of bonds between the monomers (β-(1 → 3), β-(1 → 6), and α-(1 → 3)) and their location in the cell (cell wall PSs, exoPSs, and endoPSs). Exopolysaccharides (EPSs) are most frequently studied fungal PSs but their definition, classification, and origin are still not clear and should be explained. Ascomycota and Basidiomycota fungi producing EPS have different ecological positions (saprotrophic and endophytic, pathogenic or symbiotic-mycorrhizae fungi); therefore, EPSs play different biological functions, for example in the protection against environmental stress factors and in interactions with other organisms. EPSs obtained from Ascomycota and Basidiomycota fungal cultures are known for their antioxidant, immunostimulating, antitumor, and antimicrobial properties. The major objective of the presented review article was to provide a detailed description of the state-of-the-art knowledge of the effectiveness of EPS production by filamentous and yeast Ascomycota and Basidiomycota fungi and techniques of derivation of EPSs, their biochemical characteristics, and biological properties allowing comprehensive analysis as well as indication of similarities and differences between these fungal groups. Understanding the role of EPSs in a variety of processes and their application in food or pharmaceutical industries requires improvement of the techniques of their derivation, purification, and characterization. The detailed analyses of data concerning the derivation and application of Ascomycota and Basidiomycota EPSs can facilitate development and trace the direction of application of these EPSs in different branches of industry, agriculture, and medicine.

Laccase-mediated synthesis of a phenoxazine compound with antioxidative and dyeing properties--the optimisation process

This study demonstrates the optimisation of the main parameters of the laccase-mediated biosynthesis of high-intensity-coloured orange phenoxazine compound, 2-amino-3-oxo-3H-phenoxazine-8-sulfonic acid, and the antioxidative and dyeing properties. Among optimised parameters were the pH value, the activity of laccase, and the high concentration of the precursor as the necessary step in terms of dye synthesis scale-up. The high concentration of the precursor of ca. 10 g/L can be transformed totally by laccase at the activity of 30 U/g during 12 hours, in an optimised and standardised process in nearly 100% yield of synthesis. The obtained dye exhibited good dyeing properties determined according to the ISO standards. Antioxidative activities were detected for phenoxazinone dye using two independent methods, the chemiluminescence assay and the ABTS free radical-scavenging test, with the values of EC50 for the tested phenoxazine dye amounting 189.8 μg/mL and 1428 μg/mL, respectively. Despite the presence of the phenoxazine core in the structure of this dye, no antibacterial capacity was noted.

Fungus Cerrena unicolor as an effective source of new antiviral, immunomodulatory, and anticancer compounds

In the report, three bioactive fractions from Cerrena unicolor: laccase (LAC), endopolysaccharides (c-EPL), and low molecular weight (ex-LMS) were tested for the first time towards their antiviral, immunostimulatory, cytotoxic and antiproliferative effect. The immunomodulatory activity was studied by means of THP-1-derived macrophages able to synthesize and secrete IL-6 and TNF-α. We used cervical carcinoma cell lines SiHa (ATCC, HTB-35) and CaSki (ATCC, CRL 1550) to determine antitumor activity and human skin fibroblasts (HSF) as a control. SiHa and L929 cell lines were used in the antiviral activity assay to propagate HHV-1 and EMCV, respectively. LAC was the most active against HSV at an early stage of viral replication, whereas the activity of laccase against EMCV was evident after incubation of the virus with LAC before and after the adsorption step. Moreover, the investigations showed that the fungal c-EPL fraction stimulated the production and secretion of TNF-α and IL-6 by THP-1-derived macrophages up to a level of 2000 pg/ml and 400 pg/ml, respectively. It was indicated for the first time that the LAC and ex-LMS fractions exhibited anticancer activity. This resulted from their cytotoxic or antiproliferative action against the investigated tumor cells at concentrations above 250 μg/ml and 10 μg/ml, respectively.

Correlation between the production of exopolysaccharides and oxalic acid secretion by Ganoderma applanatum and Tyromyces palustris

The secretion of exopolysaccharides and oxalic acid in cultures of a white rot Ganoderma applanatum strain and a brown rot Tyromyces palustris strain were tested in terms of culture time, pH range, and temperature. The high yield of exopolysaccharides (EPS) required a moderate temperature of 28 °C for G. applanatum and 20 °C for T. palustris. G. applanatum and T. palustris accumulated more EPS when the concentration of the carbon source (maltose for G. applanatum and fructose for T. palustris) was 30 g/L. The results indicate that the production of oxalic acid by G. applanatum is correlated with the initial pH value of the culture medium and the concentration of oxalic acid increased to 1.66 ± 0.2 mM at the initial pH of 6.5 during the fungal growth. During the growth of T. palustris, the reduction of the initial pH value of the growing medium lowered the oxalic acid concentration from 7.7 ± 0.6 mM at pH 6.0 to 1.99 ± 0.2 mM at pH 3.5. T. palustris accumulated considerably more oxalic acid than G. applanatum and its presence did not affect significantly the production of exopolysaccharides. We also observed that the maximum amounts of exopolysaccharides secreted during cultivation of G. applanatum and T. palustris were 45.8 ± 1.2 and 19.1 ± 1.2 g/L, respectively.

Effective stimulation of the biotechnological potential of the medicinal white rot fungus: Phellinus pini by menadione-mediated oxidative stress

The effect of menadione (MQ; 2-methyl-1,4-naphtoquinone), a superoxide-generating agent, on the natural biodegradation system in the medicinal white rot fungus Phellinus pini was determined. While measuring the activities of extracellular manganese-dependent peroxidase (MnP) and intracellular chitinase, it was found that the application of MQ (0.75 mM) distinctly stimulated the activities of these enzymes in comparison to the control values (without MQ). Using the capillary electrophoresis (CE) method, an increase in the extracellular oxalic acid (OXA) concentration was detected during the first days after the addition of MQ. It was observed that the rate of intracellular proteolysis at pH 3.5 evidently decreased under oxidative stress conditions. Contrary to these results, the activities of serine proteases at pH 9.5 measured against fluorogenic peptide substrates distinctly increased in stressed cultures. The MQ treatment also caused an evident increase in the catalase (CAT) activity, as well as the levels of superoxide anion radicals (SORs), formaldehyde (FA), and phenolic compounds (PHC) in the experimental cultures. The results obtained confirm that prooxidants may find application as an effective way to stimulate biotechnological production of MnP and chitinase by white rot fungi.

Characterization of cellobiose dehydrogenase and its FAD-domain from the ligninolytic basidiomycete Pycnoporus sanguineus

Cellobiose dehydrogenase (CDH), an extracellular flavocytochrome produced by several wood-degrading fungi, was detected in the culture supernatant of the selective delignifier Pycnoporus sanguineus maintained on a cellulose-based liquid medium. Cellobiose dehydrogenase was purified as two active fractions: CDH1-FAD (flavin domain) (40.4 fold) with recovery of 10.9% and CDH1 (flavo-heme enzyme) (54.7 fold) with recovery of 9.8%. As determined by SDS-PAGE, the molecular mass of the purified enzyme was found to be 113.4kDa and its isoelectric point was 4.2, whereas these values for the FAD-domain were 82.7kDa and pI=6.7. The carbohydrate content of the purified enzymes was 9.2%. In this work, the cellobiose dehydrogenase gene cdh1 and its corresponding cDNA from fungus P. sanguineus were isolated, cloned, and characterized. The 2310bp full-length cDNA of cdh1 encoded a mature CDH protein containing 769 amino acids, which was preceded by a signal peptide of 19 amino acids. Moreover, both active fractions were characterized in terms of kinetics, temperature and pH optima, and antioxidant properties.

New bioactive fungal molecules with high antioxidant and antimicrobial capacity isolated from Cerrena unicolor idiophasic cultures

Three bioactive fractions, extracellular laccase (ex-LAC), crude endopolysaccharides (c-EPL), and a low molecular subfraction of secondary metabolites (ex-LMS), were isolated from the idiophasic cultures of the white rot fungus Cerrena unicolor. For the first time, we determined the antioxidant properties of these samples by chemiluminometric measurement (a) and assessment of the scavenging effect on ABTS (b) and the DPPH reduction rate (c). The highest reducing capability was found for the ex-LMS fraction: 39-90% for (a), 20-90% for (b), and 10-59% for (c) at the concentration of 6.25-800 µg/mL. The scavenging abilities of the C. unicolor c-EPL were between 36 and 70% for (a), 2 and 60% for (b), and 28 and 32% for (c) at the concentration of 6.25-800 µg/mL. A very high prooxidative potential was observed for the ex-LAC probes. The preliminary toxicity tests were done using the Microtox system and revealed the following percentage of the toxic effect against Vibrio fischeri: 85.37% for c-EPL, 50.67% for ex-LAC, and 99.8% for ex-LMS, respectively. The ex-LAC sample showed the antibacterial activity against Escherichia coli, c-EPL against Staphylococcus aureus, and ex-LMS against both bacterial strains, respectively, but the stronger inhibitory effect was exerted on S. aureus.

Vascular prostheses with covalently bound gentamicin and amikacin reveal superior antibacterial properties than silver-impregnated ones--an in vitro study

OBJECTIVE

This study aims to compare the antibacterial activities of vascular prostheses: silver-impregnated and modified with covalently immobilised antibiotics.

MATERIALS AND METHODS

Six types of protein-sealed vascular prostheses were modified with amikacin and gentamicin according to the method described in the Polish Patent Office. Their antimicrobial properties were estimated against 14 reference and clinical strains and compared with those of InterGard Silver grafts. Cytotoxicity of the tested grafts was estimated against human skin fibroblasts.

RESULTS

Prostheses modified with antibiotics in a stable covalent mode were found to be much more effective against bacterial growth and biofilm formation, as well as in case of methicillin-resistant Staphylococcus aureus (MRSA), than InterGard Silver. They inhibited the bacterial growth for at least 30 days, without losing higher than 10% of the initial amount of its drug content. They were also good, non-toxic matrices for growth of human skin fibroblasts.

CONCLUSIONS

Prostheses modified with covalently immobilised antibiotic according to our technique are much more effective than InterGard Silver at protection against bacterial growth. They are also compatible with human skin fibroblasts.