The effect of psychoactive bacteria, Bifidobacterium longum Rosell®-175 and Lactobacillus rhamnosus JB-1, on brain proteome profiles in mice

RATIONALE

The gut microbiota may play an important role in the development and functioning of the mammalian central nervous system. The assumption of the experiment was to prove that the use of probiotic bacterial strains in the diet of mice modifies the expression of brain proteins involved in metabolic and immunological processes.

OBJECTIVES AND RESULTS

Albino Swiss mice were administered with Bifidobacterium longum Rosell®-175 or Lactobacillus rhamnosus JB-1 every 24 h for 28 days. Protein maps were prepared from hippocampal homogenates of euthanized mice. Selected proteins that were statistically significant were purified and concentrated and identified using MALDI-TOF mass spectrometry. Among the analysed samples, 13 proteins were identified. The mean volumes of calcyon, secreted frizzled-associated protein 3, and catalase in the hippocampus of mice from both experimental groups were statistically significantly higher than in the control group. In mice supplemented with Lactobacillus rhamnosus JB-1, a lower mean volume of fragrance binding protein 2, shadow of prion protein, and glycine receptor α4 subunit was observed compared to the control.

CONCLUSION

The psychobiotics Bifidobacterium longum Rosell®-175 and Lactobacillus rhamnosus JB-1enhances expression of proteins involved in the activation and maturation of nerve cells, as well as myelination and homeostatic regulation of neurogenesis in mice. The tested psychobiotics cause a decrease in the expression of proteins associated with CNS development and in synaptic transmission, thereby reducing the capacity for communication between nerve cells. The results of the study indicate that psychobiotic bacteria can be used in auxiliary treatment of neurological disorders.

Effect of dietary supplementation with Lactobacillus helveticus R0052 on seizure thresholds and antiseizure potency of sodium valproate in mice

OBJECTIVE

Both animal and human studies, though limited, showed that multi-strain probiotic supplementation may reduce the number of seizures and/or seizure severity. Here, we evaluated the effect of a single strain probiotic supplementation on seizure susceptibility, antiseizure efficacy of sodium valproate, and several behavioral parameters in mice.

METHODS

Lactobacillus helveticus R0052 was given orally for 28 days. Its influence on seizure thresholds was evaluated in the ivPTZ- and electrically-induced seizure tests. The effect on the antiseizure potency of valproate was assessed in the scPTZ test. We also investigated the effects of probiotic supplementation on anxiety-related behavior (in the elevated plus maze and light/dark box tests), motor coordination (in the accelerating rotarod test), neuromuscular strength (in the grip-strength test), and spontaneous locomotor activity. Serum and brain concentrations of valproate as well as cecal contents of SCFAs and lactate were determined using HPLC method.

RESULTS

L. helveticus R0052 significantly increased the threshold for the 6 Hz-induced psychomotor seizure. There was also a slight increase in the threshold for myoclonic and clonic seizure in the ivPTZ test. L. helveticus R0052 did not affect the threshold for tonic seizures both in the maximal electroshock- and ivPTZ-induced seizure tests. No changes in the antiseizure potency of valproate against the PTZ-induced seizures were reported. Interestingly, L. helveticus R0052 increased valproate concentration in serum, but not in the brain. Moreover, L. helveticus R0052 did not produce any significant effects on anxiety-related behavior, motor coordination, neuromuscular strength, and locomotor activity. L. helveticus R0052 supplementation resulted in increased concentrations of total SCFAs, acetate, and butyrate.

CONCLUSIONS

Altogether, this study shows that a single-strain probiotic - L. helveticus R0052 may decrease seizure susceptibility and this effect can be mediated, at least in part, by increased production of SCFAs. In addition, L. helveticus R0052 may affect bioavailability of valproate, which warrants further investigations.

Investigation of the Membrane Localization and Interaction of Selected Flavonoids by NMR and FTIR Spectroscopy

In this report, we discuss the effects of undescribed flavone derivatives, HZ4 and SP9, newly isolated from the aerial parts of Hottonia palustris L. and Scleranthus perennis L. on membranes. Interaction of flavonoids with lipid bilayers is important for medicinal applications. The experiments were performed with FTIR and NMR techniques on liposomes prepared from DPPC (dipalmitoylphosphatidylcholine) and EYPC (egg yolk phosphatidylcholine). The data showed that the examined polyphenols incorporate into the polar head group region of DPPC phospholipids at both 25 °C and 45 °C. At the lower temperature, a slight effect in the spectral region of the ester carbonyl group is observed. In contrast, at 45 °C, both compounds bring about the changes in the spectral regions attributed to antisymmetric and symmetric stretching vibrations of CH2 and CH3 moieties. Similarly, as in DPPC lipids, the tested compounds interact with the fingerprint region of the polar head groups of the EYPC lipids and cause its reorganization. The outcomes obtained by NMR analyses confirmed the localization of both flavonoids in the polar heads zone. Unraveled effects of HZ4 and SP9 in respect to lipid bilayers can partly determine their biological activities and are crucial for their usability in medicine as disease-preventing phytochemicals.

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).

(1→3)-α-d-Glucooligosaccharides Increase the Killing Capacity of NK Cells against Selected Human Colon Cancer Cells

Despite the progress of medicine, colorectal cancer has occupied one of the highest positions in the rankings of cancer morbidity and mortality for many years. Thus, alternative methods of its treatment are sought. One of the newer therapeutic strategies is immunotherapy based on NK cells (natural killers), which are the body's first line of defense against cancer. The aim of the study was to verify the possibility of using (1→3)-α-d-glucooligosaccharides (GOSs) obtained via acid hydrolysis of (1→3)-α-d-glucan from the fruiting body of Laetiporus sulphureus to improve the anticancer effect of NK-92 cells, with proven clinical utility, against selected human colon adenocarcinoma cell lines LS180 and HT-29. The study revealed that the investigated oligosaccharides significantly enhanced the ability of NK-92 cells to eliminate the examined colon cancer cells, mostly by an increase in their cytotoxic activity. The most significant effect was observed in LS180 and HT-29 cells exposed to a two-times higher quantity of NK cells activated by 500 µg/mL GOS, wherein NK-92 killing properties increased for 20.5% (p < 0.001) and 24.8% (p < 0.001), respectively. The beneficial impact of (1→3)-α-d-glucooligosaccharides on the anticancer properties of NK-92 suggests their use in colon cancer immunotherapy as adjuvants; however, the obtained data require further investigation and confirmation.

Polar localization of new flavonoids from aerial parts of Scleranthus perennis and Hottonia palustris and their modulatory action on lipid membranes properties

The aim of this study was to characterize, for the first time, the interactions, location, and influence of flavonoids isolated from aerial parts of Scleranthus perennis (Caryophyllaceae) and Hottonia palustris (Primulaceae) on the properties of model lipid membranes prepared from dipalmitoylphosphatidylcholine (DPPC) and egg yolk phosphatidylcholine (EYPC). The tested compounds incorporated into liposomes into the region of the polar heads or at the water/membrane interface of DPPC phospholipids. Spectral effects accompanying the presence of polyphenols revealed their effect on ester carbonyl groups apart from SP8. All polyphenols brought about reorganization of the polar zone of liposomes as it was observed by FTIR technique. Additionally, fluidization effect was noted in the region of symmetric and antisymmetric stretching vibrations of the CH₂ and CH₃ groups with exception to HZ2 and HZ3. Similarly, in EYPC liposomes, they interacted mainly with the regions of the choline heads of the lipids and had various effects on the carbonyl ester groups with exception to SP8. The region of polar head groups is restructured due to the presence of the additives in liposomes. The outcomes obtained using the NMR technique confirmed the locations of all of the tested compounds in the polar zone and indicated a flavonoid-dependent modifying effect towards lipid membranes. HZ1 and SP8 raised motional freedom in this region whereas opposite effect was revealed for HZ2 and HZ3. In the hydrophobic region restricted mobility was noted. In this report we discuss the mechanism of previously undescribed flavonoids in terms of their actions on membranes.

Response of murine gut microbiota to a prebiotic based on oligosaccharides derived via hydrolysis of fungal α-(1→3)-d-glucan: Preclinical trial study on mice

We investigated the modulating effect of α-(1→3)-glucooligosaccharides (GOS), i.e. a product of fungal α-(1→3)-d-glucan hydrolysis, on the gut microbiota composition. Mice were fed with a GOS-supplemented diet and two control diets for 21 days, and fecal samples were collected at 0, 1, and 3-week time points. The bacterial community composition was determined by 16S rRNA gene Illumina sequencing. The gut microbiota of the GOS-supplemented mice showed profound time-dependent changes in the taxonomic composition; however, we did not observe significant changes in α-diversity indices. The biggest number of genus abundance shifts after 1 week of the treatment was noticed between the group of the GOS-supplemented mice and the controls; however, the differences were still relevant after the 3-week treatment. The GOS-supplemented mice displayed higher abundance of Prevotella spp., with a concomitant decrease in the abundance of Escherichia-Shigella. Hence, GOS seems to be a promising candidate for a new prebiotic.

Phytochemical Profiling of Extracts from Rare Potentilla Species and Evaluation of Their Anticancer Potential

Despite the common use of Potentilla L. species (Rosaceae) as herbal medicines, a number of species still remain unexplored. Thus, the present study is a continuation of a study evaluating the phytochemical and biological profiles of aqueous acetone extracts from selected Potentilla species. Altogether, 10 aqueous acetone extracts were obtained from the aerial parts of P. aurea (PAU7), P. erecta (PER7), P. hyparctica (PHY7), P. megalantha (PME7), P. nepalensis (PNE7), P. pensylvanica (PPE7), P. pulcherrima (PPU7), P. rigoi (PRI7), and P. thuringiaca (PTH7), leaves of P. fruticosa (PFR7), as well as from the underground parts of P. alba (PAL7r) and P. erecta (PER7r). The phytochemical evaluation consisted of selected colourimetric methods, including total phenolic (TPC), tannin (TTC), proanthocyanidin (TPrC), phenolic acid (TPAC), and flavonoid (TFC) contents, as well as determination of the qualitative secondary metabolite composition by the employment of LC-HRMS (liquid chromatography-high-resolution mass spectrometry) analysis. The biological assessment included an evaluation of the cytotoxicity and antiproliferative properties of the extracts against human colon epithelial cell line CCD841 CoN and human colon adenocarcinoma cell line LS180. The highest TPC, TTC, and TPAC were found in PER7r (326.28 and 269.79 mg gallic acid equivalents (GAE)/g extract and 263.54 mg caffeic acid equivalents (CAE)/g extract, respectively). The highest TPrC was found in PAL7r (72.63 mg catechin equivalents (CE)/g extract), and the highest TFC was found in PHY7 (113.29 mg rutin equivalents (RE)/g extract). The LC-HRMS analysis showed the presence of a total of 198 compounds, including agrimoniin, pedunculagin, astragalin, ellagic acid, and tiliroside. An examination of the anticancer properties revealed the highest decrease in colon cancer cell viability in response to PAL7r (IC₅₀ = 82 µg/mL), while the strongest antiproliferative effect was observed in LS180 treated with PFR7 (IC₅₀ = 50 µg/mL) and PAL7r (IC₅₀ = 52 µg/mL). An LDH (lactate dehydrogenase) assay revealed that most of the extracts were not cytotoxic against colon epithelial cells. At the same time, the tested extracts for the whole range of concentrations damaged the membranes of colon cancer cells. The highest cytotoxicity was observed for PAL7r, which in concentrations from 25 to 250 µg/mL increased LDH levels by 145.7% and 479.0%, respectively. The previously and currently obtained results indicated that some aqueous acetone extracts from Potentilla species have anticancer potential and thus encourage further studies in order to develop a new efficient and safe therapeutic strategy for people who have been threatened by or suffered from colon cancer.

Chemical Composition and Antimicrobial Activity of New Honey Varietals

Due to a widespread occurrence of multidrug-resistant pathogenic strains of bacteria, there is an urgent need to look for antimicrobial substances, and honey with its antimicrobial properties is a very promising substance. In this study, we examined for the first time antimicrobial properties of novel varietal honeys, i.e., plum, rapeseed, Lime, Phacelia, honeydew, sunflower, willow, and multifloral-P (Prunus spinosa L.), multifloral-AP (Acer negundo L., Prunus spinosa L.), multifloral-Sa (Salix sp.), multifloral-Br (Brassica napus L.). Their antimicrobial activity was tested against bacteria (such as Escherichia coli, Bacillus circulans, Staphylococcus aureus, Pseudomonas aeruginosa), yeasts (such as Saccharomyces cerevisiae and Candida albicans) and mold fungi (such as Aspergillus niger). In tested honeys, phenolic acids constituted one of the most important groups of compounds with antimicrobial properties. Our study found phenolic acids to occur in greatest amount in honeydew honey (808.05 µg GAE/g), with the highest antifungal activity aiming at A. niger. It was caffeic acid that was discovered in the greatest amount (in comparison with all phenolic acids tested). It was found in the highest amount in such honeys as phacelia-356.72 µg/g, multifloral (MSa) and multifloral (MBr)-318.9 µg/g. The highest bactericidal activity against S. aureus was found in multifloral honeys MSa and MBr. Additionally, the highest amount of syringic acid and cinnamic acid was identified in rapeseed honey. Multifloral honey (MAP) showed the highest bactericidal activity against E. coli, and multifloral honey (MSa) against S. aureus. Additionally, multifloral honey (MBr) was effective against E. coli and S. aureus. Compounds in honeys, such as lysozyme-like and phenolic acids, i.e., coumaric, caffeic, cinnamic and syringic acids, played key roles in the health-benefit properties of honeys tested in our study.

EVALUATION OF THE CARIOGENICITY OF PREBIOTIC (1→3)-α-D-GLUCOOLIGOSACCHARIDES

One of the important features of prebiotics is their beneficial effect on the health of the host, which consists in the inhibition of the growth of harmful bacteria, including strains causing caries. The aim of the present study was to evaluate the cariogenic potential of a hydrolyzate of (1→3)-α-D-glucan (GOS) isolated from fruiting bodies of Laetiporus sulphureus, consisting of (1→3)-α-D-glucooligosaccharides (85.6%) and glucose (14.4%). The study was conducted in cultures of cariogenic bacteria belonging to the genus Streptococcus (S. mutans CAPM 6067, S. sobrinus DSMZ 20381, S. sobrinus/downei CCUG 21020, and S. sanguis ATCC 10556). The investigation of the cariogenicity of GOS included examination of the influence of the preparation on the growth of the above mentioned bacteria, their ability to synthesize mutan, and the formation of a sucrose-dependent biofilm. GOS significantly inhibited the growth of the investigated streptococci, and the observed beneficial effect was stronger than the changes induced by a commercial prebiotic preparation containing a mixture of fructooligosaccharides (FOS). Furthermore, GOS inhibited the mutan synthesis by the above mentioned bacteria but did not exert an impact on the formation of artificial dental plaque. In conclusion, the studies conducted showed low cariogenicity of GOS and confirmed the safety of its use as a dietary supplement.

Anticancer potential of acetone extracts from selected Potentilla species against human colorectal cancer cells

Cinquefoils have been widely used in local folk medicine in Europe and Asia to manage various gastrointestinal inflammations and/or infections, certain forms of cancer, thyroid gland disorders, and wound healing. In the present paper, acetone extracts from aerial parts of selected Potentilla species, namely P. alba (PAL7), P. argentea (PAR7), P. grandiflora (PGR7), P. norvegica (PN7), P. recta (PRE7), and the closely related Drymocalis rupestris (syn. P. rupestris) (PRU7), were analysed for their cytotoxicity and antiproliferative activities against human colon adenocarcinoma cell line LS180 and human colon epithelial cell line CCD841 CoN. Moreover, quantitative assessments of the total polyphenolic (TPC), total tannin (TTC), total proanthocyanidins (TPrC), total flavonoid (TFC), and total phenolic acid (TPAC) were conducted. The analysis of secondary metabolite composition was carried out by LC-PDA-HRMS. The highest TPC and TTC were found in PAR7 (339.72 and 246.92 mg gallic acid equivalents (GAE)/g extract, respectively) and PN7 (332.11 and 252.3 mg GAE/g extract, respectively). The highest TPrC, TFC, and TPAC levels were found for PAL7 (21.28 mg catechin equivalents (CAT)/g extract, 71.85 mg rutin equivalents (RE)/g extract, and 124.18 mg caffeic acid equivalents (CAE)/g extract, respectively). LC-PDA-HRMS analysis revealed the presence of 83 compounds, including brevifolincarboxylic acid, ellagic acid, pedunculagin, agrimoniin, chlorogenic acid, astragalin, and tiliroside. Moreover, the presence of tri-coumaroyl spermidine was demonstrated for the first time in the genus Potentilla. Results of the MTT assay revealed that all tested extracts decreased the viability of both cell lines; however, a markedly stronger effect was observed in the colon cancer cells. The highest selectivity was demonstrated by PAR7, which effectively inhibited the metabolic activity of LS180 cells (IC₅₀ = 38 μg/ml), while at the same time causing the lowest unwanted effects in CCD841 CoN cells (IC₅₀ = 1,134 μg/ml). BrdU assay revealed a significant decrease in DNA synthesis in both examined cell lines in response to all investigated extracts. It should be emphasized that the tested extracts had a stronger effect on colon cancer cells than normal colon cells, and the most significant antiproliferative properties were observed in the case of PAR7 (IC₅₀ LS180 = 174 μg/ml) and PN7 (IC₅₀ LS180 = 169 μg/ml). The results of LDH assay revealed that all tested extracts were not cytotoxic against normal colon epithelial cells, whereas in the cancer cells, all compounds significantly damaged cell membranes, and the observed effect was dose-dependent. The highest cytotoxicity was observed in LS180 cells in response to PAR7, which, in concentrations ranging from 25 to 250 μg/ml, increased LDH release by 110%–1,062%, respectively. Performed studies have revealed that all Potentilla species may be useful sources for anti-colorectal cancer agents; however, additional research is required to prove this definitively.

Comparative Nanopore Sequencing-Based Evaluation of the Midgut Microbiota of the Summer Chafer (Amphimallon solstitiale L.) Associated with Possible Resistance to Entomopathogenic Nematodes

Root-feeding Amphimallon solstitiale larvae and certain other scarab beetles are the main soil-dwelling pests found in Europe, while entomopathogenic nematodes (EPN) have been used as a biocontrol agent against these species. Our study provides the first detailed characterization of the bacterial community of the midgut in wild A. solstitiale larvae, based on the nanopore sequencing of the 16S rRNA gene. In the whole dataset, we detected 2586 different genera and 11,641 species, with only 83 diverse bacterial genera shared by all studied individuals, which may represent members of the core midgut microbiota of A. solstitiale larvae. Subsequently, we compared the midgut microbiota of EPN-resistant and T0 (prior to EPN exposure) individuals, hypothesizing that resistance to this parasitic infection may be linked to the altered gut community. Compared to the control, the resistant insect microbiota demonstrated lower Shannon and Evenness indices and significant differences in the community structure. Our studies confirmed that the gut microbiota alternation is associated with resistant insects; however, there are many processes involved that can affect the bacterial community. Further research on the role of gut microbiota in insect-parasitic nematode interaction may ultimately lead to the improvement of biological control strategies in insect pest management.

Screening and Molecular Identification of Bacteria from the Midgut of Amphimallon solstitiale Larvae Exhibiting Antagonistic Activity against Bacterial Symbionts of Entomopathogenic Nematodes

Entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) are a group of organisms capable of infecting larvae of insects living in soil, including representatives of the family Scarabaeidae. Their insecticidal activity is related to the presence of symbiotic bacteria Xenorhabdus spp. or Photorhabdus spp. in the alimentary tract, which are released into the insect body, leading to its death caused by bacterial toxins and septicemia. Although the antibacterial activities of symbionts of entomopathogenic nematodes have been well described, there is insufficient knowledge of the interactions between these bacteria and microorganisms that naturally inhabit the alimentary tract of insects infested by nematodes. In this study, 900 bacterial strains isolated from midgut samples of Amphimallon solstitiale larvae were tested for their antagonistic activity against the selected five Xenorhabdus and Photorhabdus species. Cross-streak tests showed significant antibacterial activity of 20 isolates. These bacteria were identified as Bacillus [Brevibacterium] frigoritolerans, Bacillus toyonensis, Bacillus wiedmannii, Chryseobacterium lathyri, Chryseobacterium sp., Citrobacter murliniae, Enterococcus malodoratus, Paenibacillus sp., Serratia marcescens and Serratia sp. Since some representatives of the intestinal microbiota of A. solstitiale are able to inhibit the growth of Xenorhabdus and Photorhrhabdus bacteria in vitro, it can be assumed that this type of bacterial interaction may occur at certain stages of insect infection by Steinernema or Heterorhabditis nematodes.

Activation of cellular immune response in insect model host Galleria mellonella by fungal α-1,3-glucan

Alpha-1,3-glucan, in addition to β-1,3-glucan, is an important polysaccharide component of fungal cell walls. It is reported for many fungal species, including human pathogenic genera: Aspergillus, Blastomyces, Coccidioides, Cryptococcus, Histoplasma and Pneumocystis, plant pathogens, e.g. Magnaporthe oryzae and entomopathogens, e.g. Metarhizium acridum. In human and plant pathogenic fungi, α-1,3-glucan is considered as a shield for the β-1,3-glucan layer preventing recognition of the pathogen by the host. However, its role in induction of immune response is not clear. In the present study, the cellular immune response of the greater wax moth Galleria mellonella to Aspergillus niger α-1,3-glucan was investigated for the first time. The changes detected in the total hemocyte count (THC) and differential hemocyte count (DHC), formation of hemocyte aggregates and changes in apolipophorin III localization indicated activation of G. mellonella cellular mechanisms in response to immunization with A. niger α-1,3-glucan. Our results, which have clearly demonstrated the response of the insect immune system to this fungal cell wall component, will help in understanding the α-1,3-glucan role in immune response against fungal pathogens not only in insects but also in mammals, including humans.

Steinernema sandneri n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Poland

A new species of entomopathogenic nematodes, Steinernema sandneri n. sp., was recovered by baiting from Poland. Its morphological traits indicate that the new species is a member of the feltiae-kraussei group. A body length of 843 (708-965) μm, a more anterior position of excretory pore (56 μm), and the lower D% value (40 vs > 46) discriminate this species from most of the other group members. The first-generation males of S. sandneri n. sp. can be distinguished from the other clade members by a 60 μm long spicule, a relatively long gubernaculum (GS% = 79), and the position of the excretory pore (80 μm). Phylogenetic analysis of the ITS rDNA, D2D3 of 28 S rDNA, and cox1 sequences confirmed that S. sandneri n. sp. is a new species of the feltiae-kraussei group, closely related to S. kraussei and S. silvaticum.

[German S1 guideline: obstructive sleep apnea in the context of tonsil surgery with or without adenoidectomy in children-perioperative management]

Otolaryngologic surgery is one of the most frequent operative interventions performed in children. Tonsil surgery with or without adenoidectomy due to hyperplasia of the tonsils and adenoids with obstruction of the upper airways with or without tympanic ventilation disorder is the most common of these procedures. Children with a history of sleep apnoea (OSA) suffer from a significantly increased risk of perioperative respiratory complications. Cases of death and severe permanent neurologic damage have been reported due to apnoea and increased opioid sensitivity. The current guideline represents a pragmatic risk-adjusted approach. Patients with confirmed or suspected OSA should be treated perioperatively according to their individual risks and requirements, in order to avoid severe permanent damage.

The FT-IR and Raman Spectroscopies as Tools for Biofilm Characterization Created by Cariogenic Streptococci

Fourier transform infrared (FT-IR) and Raman spectroscopy and mapping were applied to the analysis of biofilms produced by bacteria of the genus Streptococcus. Bacterial biofilm, also called dental plaque, is the main cause of periodontal disease and tooth decay. It consists of a complex microbial community embedded in an extracellular matrix composed of highly hydrated extracellular polymeric substances and is a combination of salivary and bacterial proteins, lipids, polysaccharides, nucleic acids, and inorganic ions. This study confirms the value of Raman and FT-IR spectroscopies in biology, medicine, and pharmacy as effective tools for bacterial product characterization.

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.

Bacteria from the Midgut of Common Cockchafer (Melolontha melolontha L.) Larvae Exhibiting Antagonistic Activity Against Bacterial Symbionts of Entomopathogenic Nematodes: Isolation and Molecular Identification

The mechanisms of action of the complex including entomopathogenic nematodes of the genera Steinernema and Heterorhabditis and their mutualistic partners, i.e., bacteria Xenorhabdus and Photorhabdus, have been well explained, and the nematodes have been commercialized as biological control agents against many soil insect pests. However, little is known regarding the nature of the relationships between these bacteria and the gut microbiota of infected insects. In the present study, 900 bacterial isolates that were obtained from the midgut samples of Melolontha melolontha larvae were screened for their antagonistic activity against the selected species of the genera Xenorhabdus and Photorhabdus. Twelve strains exhibited significant antibacterial activity in the applied tests. They were identified based on 16S rRNA and rpoB, rpoD, or recA gene sequences as Pseudomonas chlororaphis, Citrobacter murliniae, Acinetobacter calcoaceticus, Chryseobacterium lathyri, Chryseobacterium sp., Serratia liquefaciens, and Serratia sp. The culture filtrate of the isolate P. chlororaphis MMC3 L3 04 exerted the strongest inhibitory effect on the tested bacteria. The results of the preliminary study that are presented here, which focused on interactions between the insect gut microbiota and mutualistic bacteria of entomopathogenic nematodes, show that bacteria inhabiting the gut of insects might play a key role in insect resistance to entomopathogenic nematode pressure.

The Effect of Water-Soluble Polysaccharide from Jackfruit (Artocarpus heterophyllus Lam.) on Human Colon Carcinoma Cells Cultured In Vitro

Various phytochemical studies have revealed that jackfruit (Artocarpus heterophyllus Lam.) is rich in bioactive compounds, including carotenoids, flavonoids, volatile acids, tannins, and lectins. The aim of the study was to analyze the biological activity of water-soluble polysaccharide (WSP) isolated from jackfruit and to assess its immunomodulatory, cytotoxic, and anti-oxidative effects on human colon carcinoma cells in vitro. The neutral red (NR) uptake assay revealed no toxic influence of the polymer on the viability of tumor cells (HT29 and SW620). After 24 h and 48 h of incubation, the cellular viability was not lower than 94%. The metabolic activity of the cells (MTT) at the compound concentration of 250 µg/mL was higher than 92% in comparison to the control. WSP (250 µg/mL) exerted no significant effect on the morphology of the cells was determined by May-Grünwald-Giemsa staining. WSP changed nitric oxide (NOx) production by the tumor cells depending on the time of incubation and prior 2-h stimulation of the cells with E. coli 0111:B4 LPS. It significantly stimulated IL-1β production by the tumor cells. The IL-6 level increased but that of IL-10 decreased by a WSP concentration-dependent manner. No such effect was detected in SW620. The WSP had antioxidant properties. In conclusion, water-soluble polysaccharide isolated from A. heterophyllus exhibits significant biological activity towards many types of both normal and cancerous cells. Therefore, it may be considered as a useful agent in the protection of human health or in functional and dietary nutrition.

The Effect of Mushroom Extracts on Human Platelet and Blood Coagulation: In vitro Screening of Eight Edible Species

Cardiovascular diseases remain the leading global cause of mortality indicating the need to identify all possible factors reducing primary and secondary risk. This study screened the in vitro antiplatelet and anticoagulant activities of hot water extracts of eight edible mushroom species (Agaricus bisporus, Auricularia auricularia-judae, Coprinuscomatus, Ganodermalucidum, Hericium erinaceus, Lentinulaedodes, Pleurotuseryngii, and Pleurotusostreatus) increasingly cultivated for human consumption, and compared them to those evoked by acetylsalicylic acid (ASA). The antioxidant capacity and concentration of polysaccharides, phenolic compounds, organic acids, ergosterol, macro elements, and trace elements were also characterized. The most promising antiplatelet effect was exhibited by A. auricularia-judae and P. eryngii extracts as demonstrated by the highest rate of inhibition of adenosine-5′-diphosphate (ADP)-induced and arachidonic acid (AA)-induced aggregation. The response to both extracts exceeded the one evoked by 140 µmol/L of ASA in the ADP test and was comparable to it in the case of the AA test. Such a dual effect was also observed for G. lucidum extract, even though it was proven to be cytotoxic in platelets and leukocytes. The extract of P. ostreatus revealed an additive effect on AA-induced platelet aggregation. None of the mushroom extracts altered the monitored coagulation parameters (prothrombin time, prothrombin ratio, and International Normalized Ratio). The effect of mushroom extracts on platelet function was positively related to their antioxidative properties and concentration of polysaccharides and ergosterol, and inversely related to zinc concentration. The study suggests that selected mushrooms may exert favorable antiplatelet effects, highlighting the need for further experimental and clinical research in this regard.

A Report on Fungal (1→3)-α-d-glucans: Properties, Functions and Application

The cell walls of fungi are composed of glycoproteins, chitin, and α- and β-glucans. Although there are many reports on β-glucans, α-glucan polysaccharides are not yet fully understood. This review characterizes the physicochemical properties and functions of (1→3)-α-d-glucans. Particular attention has been paid to practical application and the effect of glucans in various respects, taking into account unfavourable effects and potential use. The role of α-glucans in plant infection has been proven, and collected facts have confirmed the characteristics of Aspergillus fumigatus infection associated with the presence of glucan in fungal cell wall. Like β-glucans, there are now evidence that α-glucans can also stimulate the immune system. Moreover, α-d-glucans have the ability to induce mutanases and can thus decompose plaque.

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.

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.

Hydrogel Containing an Extract of Tormentillae Rhizoma for the Treatment of Biofilm-Related Oral Diseases

In the present study, hydrogels containing the dried extract of tormentil ( Potentilla erecta (L.) Raeusch., Rosaceae) were designed and qualitatively evaluated regarding their viscosity, thixotropy, and texture properties. As mucoadhesiveness is a crucial factor determining drug retention within the oral cavity, mucoadhesive properties expressed as the work of adhesion and maximum detachment force under the presence of porcine buccal mucosa and two different models of mucoadhesive layers: mucin and gelatin discs were evaluated. The fingerprints of the analyzed tormentil extract were established by using a LC-ESI-MS method. The dominating compounds of the tested extract are oligomeric proanthocyanidins and agrimoniin. This study reveals that designed hydrogels are promising semi-solid delivery systems for the dry extract of tormentil with beneficial mucoadhesive, thixotropic, and texture characteristics and may be utilized as platforms for tormentil delivery to the oral cavity in periodontal diseases. In vitro evaluation of the efficacy of the tormentil hydrogel against cariogenic Streptococcus mutans biofilms was also performed. The hydrogel significantly reduced artificial biofilm formation. For all Streptococci, complete inhibition was revealed at a final concentration of the extract of 2 mg/mL. These beneficial characteristics, as well as the anti-biofilm activity, enable its use for dental care, but further clinical studies are required.

[Positionpaper on Telemonitoring in Sleep-Related Breathing Disorders]

The use of telemonitoring in the care of patients with Sleep-related Breathing Disorders (SBD) can enhance medical support significantly. Telemonitoring aims at helping physicians to detect therapy problems early and thus improve patients' therapy adherence. Diagnostics and therapy decisions in the telemonitoring process nevertheless remain the responsibility of sleep specialists. The selection of data monitored, their evaluation and resulting consequences fall to the physician, who makes decisions and prescribes therapy in consultation with the patient. In light of professional legal and ethical requirements, it must be ensured that the extensive changes to the process flow in sleep medicine are designed in a way to guarantee high-quality patient care. In this position paper, the German Sleep Society, the German Respiratory Society, the Association of Pneumological Hospitals and the Federal Association of German Pneumologists comment on important aspects for implementation of telemonitoring for SRBD and describe the basic conditions required for its use.

In Vitro Antiproliferative and Antioxidant Effects of Extracts from Rubus caesius Leaves and Their Quality Evaluation

The present study was performed to evaluate the effect of different extracts and subfractions from Rubus caesius leaves on two human colon cancer cell lines obtained from two stages of the disease progression lines HT29 and SW948. Tested samples inhibited the viability of cells, both HT29 and SW948 lines, in a concentration-dependent manner. The most active was the ethyl acetate fraction which, applied at the highest concentration (250 μg/mL), decreased the viability of cells (HT29 and SW948) below 66%. The extracts and subfractions were also investigated for antioxidant activities on DPPH and FRAP assays. All extracts, with the exception of water extract at a dose of 250 μg/mL, almost totally reduced DPPH. The highest Fe3+ ion reduction was shown for the diethyl and ethyl acetate fractions. It was more than 6.5 times higher (at a dose 250 μg/mL) as compared to the control. The LC-MS studies of the analysed preparations showed that all samples contain a wide variety of polyphenolics, among which ellagitannins turned out to be the main constituents with dominant ellagic acid, sanguiin H-6, and flavonol derivatives.

Enzymes in therapy of biofilm-related oral diseases

Biofilm-related infections of the oral cavity, including dental caries and periodontitis, represent the most prevalent health problems. For years, the treatment thereof was largely based on antibacterial chemical agents. Recently, however, there has been growing interest in the application of more preventive and minimally invasive biotechnological methods. This review focuses on the potential applications of enzymes in the treatment and prevention of oral diseases. Dental plaque is a microbial community that develops on the tooth surface, embedded in a matrix of extracellular polymeric substances of bacterial and host origin. Both cariogenic microorganisms and the key components of oral biofilm matrix may be the targets of the enzymes. Oxidative salivary enzymes inhibit or limit the growth of oral pathogens, thereby supporting the natural host defense system; polysaccharide hydrolases (mutanases and dextranases) degrade important carbohydrate components of the biofilm matrix, whereas proteases disrupt bacterial adhesion to oral surfaces or affect cell-cell interactions. The efficiency of the enzymes in in vitro and in vivo studies, advantages and limitations, as well as future perspectives for improving the enzymatic strategy are discussed.

Cultivation and utility of Piptoporus betulinus fruiting bodies as a source of anticancer agents

Piptoporus betulinus is a wood-rotting basidiomycete used in medicine and biotechnology. However, to date, no indoor method for cultivation of this mushroom fruiting bodies has been developed. Here we present the first report of successful production of P. betulinus mature fruiting bodies in artificial conditions. Four P. betulinus strains were isolated from natural habitats and their mycelia were inoculated into birch sawdust substrate supplemented with organic additives. All the strains effectively colonized the medium but only one of them produced fruiting bodies. Moisture and organic supplementation of the substrate significantly determined the fruiting process. The biological efficiency of the P. betulinus PB01 strain cultivated on optimal substrate (moisture and organic substance content of 55 and 65 and 25 or 35 %, respectively) ranged from 12 to 16 %. The mature fruiting bodies reached weight in the range from 50 to 120 g. Anticancer properties of water and ethanol extracts isolated from both cultured and nature-derived fruiting bodies of P. betulinus were examined in human colon adenocarcinoma, human lung carcinoma and human breast cancer cell lines. The studies revealed antiproliferative and antimigrative properties of all the investigated extracts. Nevertheless the most pronounced effects demonstrated the ethanol extracts, obtained from fruiting bodies of cultured P. betulinus. Summarizing, our studies proved that P. betulinus can be induced to fruit in indoor artificial culture and the cultured fruiting bodies can be used as a source of potential anticancer agents. In this respect, they are at least as valuable as those sourced from nature.

[Cologne Statement for Medical Care of Refugees]

The Cologne statement resulted from both regional and nationwide controversial discussions about meaning and purpose of an initial examination for infectious diseases of refugees with respect to limited time, personnel and financial resources. Refugees per se are no increased infection risk factors for the general population as well as aiders, when the aiders comply with general hygiene rules and are vaccinated according to the recommendations of the German Standing Committee on Vaccination (STIKO). This is supported by our own data. Based on individual medical history, refugees need medical care, which is offered purposeful, economic, humanitarian and ethical. In addition to medical confidentiality, the reporting obligation according § 34 Infection Protection Act (IPA) and the examination concerning infectious pulmonary tuberculosis according to § 36 (4) IPA must be considered.

(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.

Purification and properties of an α-(1 → 3)-glucanase (EC 3.2.1.84) from Trichoderma harzianum and its use for reduction of artificial dental plaque accumulation

Extracellular α-(1 → 3)-glucanase (mutanase, EC 3.2.1.84) produced by Trichoderma harzianum CCM F-340 was purified to homogeneity by ultrafiltration followed by ion exchange and hydrophobic interaction chromatography, and final chromatofocusing. The enzyme was recovered with an 18.4-fold increase in specific activity and a yield of 4.3%. Some properties of the α-(1 → 3)-glucanase were investigated. The molecular mass of the enzyme is 67 kDa, as estimated by SDS/PAGE, its isoelectric point 7.1, and the carbohydrate content 3%. The pH and temperature optima are 5.5 and 45°C, respectively. The enzyme is stable over a pH range of 4.5-6.0 and up to 45°C for 1 h. The Km and Vmax under standard assay conditions are 0.73 mg/ml and 11.39 x 10(-2) µmol/min/mg protein, respectively. The enzyme activity is stimulated by addition of Mg(2+) and Na(+), and significantly inhibited by Hg(2+). The α-(1 → 3)-glucanase preparation preferentially catalyzed the hydrolysis of various streptococcal mutans and fungal α-(1 → 3)-glucans. The 20-residue N-terminal sequence of the enzyme is identical with those of other α-(1 → 3)-glucanases from the genus Trichoderma, and highly similar to those from other fungi. The purified α-(1 → 3)-glucanase was effective in preventing artificial dental plaque formation. The easy purification from fermentation broth and high stability, and the effective inhibition of oral biofilm accumulation make this α-(1 → 3)-glucanase highly useful for industrial and medical application.

Purification and properties of an α-(1 → 3)-glucanase (EC 3.2.1.84) from Trichoderma harzianum and its use for reduction of artificial dental plaque accumulation

Extracellular α-(1 → 3)-glucanase (mutanase, EC 3.2.1.84) produced by Trichoderma harzianum CCM F-340 was purified to homogeneity by ultrafiltration followed by ion exchange and hydrophobic interaction chromatography, and final chromatofocusing. The enzyme was recovered with an 18.4-fold increase in specific activity and a yield of 4.3%. Some properties of the α-(1 → 3)-glucanase were investigated. The molecular mass of the enzyme is 67 kDa, as estimated by SDS/PAGE, its isoelectric point 7.1, and the carbohydrate content 3%. The pH and temperature optima are 5.5 and 45°C, respectively. The enzyme is stable over a pH range of 4.5-6.0 and up to 45°C for 1 h. The Km and Vmax under standard assay conditions are 0.73 mg/ml and 11.39 x 10(-2) µmol/min/mg protein, respectively. The enzyme activity is stimulated by addition of Mg(2+) and Na(+), and significantly inhibited by Hg(2+). The α-(1 → 3)-glucanase preparation preferentially catalyzed the hydrolysis of various streptococcal mutans and fungal α-(1 → 3)-glucans. The 20-residue N-terminal sequence of the enzyme is identical with those of other α-(1 → 3)-glucanases from the genus Trichoderma, and highly similar to those from other fungi. The purified α-(1 → 3)-glucanase was effective in preventing artificial dental plaque formation. The easy purification from fermentation broth and high stability, and the effective inhibition of oral biofilm accumulation make this α-(1 → 3)-glucanase highly useful for industrial and medical application.

Successful large-scale production of fruiting bodies of Laetiporus sulphureus (Bull.: Fr.) Murrill on an artificial substrate

Laetiporus sulphureus is an edible wood-rotting basidiomycete fungus whose fruiting bodies contain substances with verified therapeutic evidences and large amounts of α-(1 → 3)-glucan which is used as an effective inducer of microbial α-(1 → 3)-glucanases. However, production of mature fruiting bodies of this species under artificially controlled conditions has not been reported until now. Here, we provide the first report of successful initiation and development of L. sulphureus fruiting bodies in large-scale experiments. Twelve Laetiporus strains were isolated from a natural habitat. A synthetic log production system with a substrate composed of a mixture of sawdust enriched with organic and inorganic additives was developed. It was found that shocking the fungus mycelium with cold water or low temperature was the only suitable method for forced fruiting of L. sulphureus strains. Primordia of two strains were initiated already after 5-6 days from induction, and after another 2 days, they began to develop into fruiting bodies. Carpophores appeared fastest on substrates with high organic supplementation (40-45 %) and a low moisture content (40 %). The resulting mature fruiting bodies reached a weight of 200-300 g. The method of cultivation presented in this paper opens the way to commercial production of this valuable basidiomycete.

Structural diversity of streptococcal mutans synthesized under different culture and environmental conditions and its effect on mutanase synthesis

Streptococcal mutans synthesized under different conditions by growing cultures or by their glucosyltransferases were shown to exhibit a great structural and property diversity. Culturing and environmental factors causing structural differences in mutans were specified. All of the obtained biopolymers (76 samples) were water-insoluble and most of them (72) had a structure with a predominance of α-(1→3)-linked glucose (i.e., the content of α-(1→3)-linkages in the glucan was always higher than 50%, but did not exceed 76%). An exception were four glucans containing more than 50% of α-(1→6)-sequences. In these structurally unique mutans, the ratio of α-(1→3)- to α-(1→6)-bonds ranged from 0.75 to 0.97. Aside from one polymer, all others had a heavily branched structures and differed in the number of α-(1→3), α-(1→6), and α-(1→3,6) linkages and their mutual proportion. The induction of mutanase production in shaken flask cultures of Trichoderma harzianum by the structurally diverse mutans resulted in enzyme activities ranging from 0.144 to 1.051 U/mL. No statistical correlation was found between the total percentage content of α-(1→3)-linkages in the α-glucan and mutanase activity. Thus, despite biosynthetic differences causing structural variation in the mutans, it did not matter which mutan structures were used to induce mutanase production.

Gene cloning, expression, and characterization of mutanase from Paenibacillus curdlanolyticus MP-1

Mutanases hydrolyze d-glucosidic linkages of α-1,3-linked polysaccharides which are important components of dental plaque. Therefore, these enzymes can be useful in preventive oral hygiene. A gene encoding mutanase was cloned from soil-isolated Paenibacillus curdlanolyticus MP-1 and expressed in Escherichia coli, and the resulting recombinant enzyme was characterized. The nucleotide sequence of the mutanase gene consisted of 3786 nucleotides encoding a protein of 1261 amino acids with a theoretical molecular weight of 131.62kDa. The deduced amino acid sequence exhibited a high degree of similarity with mutanases of Paenibacillus sp. KSM-M126 and Paenibacillus humicus NA1123, with 84% and 80% identity, respectively. The recombinant enzyme was purified 17.5-fold to homogeneity with a recovery of 37%. The purified mutanase showed optimal activity at pH 6.0 and 45°C, and was completely stable at pH 4.0-9.5 and up to 45°C. The enzyme was specific for α-1,3-glucosidic linkages and effectively solubilized fungal α-1,3-glucans and streptococcal mutans, releasing nigerooligosaccharides. The mutanase did not hydrolyze a synthetic substrate readily hydrolyzed by exoglucanases and the enzyme activity was not suppressed in the presence of deoxynojirimycin, an inhibitor of exo-type enzymes. These results suggest an endohydrolytic mode of action.

Comparative studies on the induction of Trichoderma harzianum mutanase by α-(1→3)-glucan-rich fruiting bodies and mycelia of Laetiporus sulphureus

Mutanase (α-(1→3)-glucanase) is a little-known inductive enzyme that is potentially useful in dentistry. Here, it was shown that the cell wall preparation (CWP) obtained from the fruiting body or vegetative mycelium of polypore fungus Laetiporus sulphureus is rich in α-(1→3)-glucan and can be successfully used for mutanase induction in Trichoderma harzianum. The content of this biopolymer in the CWP depended on the age of fruiting bodies and increased along with their maturation. In the case of CWP prepared from vegetative mycelia, the amount of α-(1→3)-glucan depended on the mycelium age and also on the kind of medium used for its cultivation. All CWPs prepared from the individually harvested fruiting body specimens induced high mutanase activity (0.53–0.82 U/mL) in T. harzianum after 3 days of cultivation. As for the CWPs obtained from the hyphal mycelia of L. sulpureus, the maximal enzyme productivity (0.34 U/mL after 3 days of incubation) was recorded for CWP prepared from the 3 week-old mycelium cultivated in Sabouraud medium. Statistically, a high positive correlation was found between the total percentage content of α-(1→3)-glucan in the CWP and the mutanase activity.