Biotehnološka razgradnja i molekularni mehanizmi razgradnje drveta pomoću selektivnih gljiva, uzročnika bijele truleži

Microbial mechanisms of lignin degradation may be utilised for solid-state fermentations other than biopulping, during which the selective conversion of lignin is required. The current paper reviews current work into selective lignin conversion, with emphasis on the contributions made by our research group, which consists of researchers from five different laboratories. Three of them cooperate within Wood K plus. The recent research of this group has focussed on fermentations utilising the unique metabolism of selective white-rot fungi to modify wood surfaces during relatively short fermentation times of less than one week and on research into the molecular mechanisms causing these modifications. Lignin degradation by selective fungi (e.g. Ceriporiopsis subvermispora and species of the genus Phlebia) on the wood surfaces was significant after three days. After seven days the overall lignin content of spruce wood shavings was reduced by more than 3.5 %. Lignin loss was accompanied by an increase of extractable substances. To evaluate small changes and to trace the fungal modification processes, Fourier transform infrared spectroscopic (FTIR) techniques and electron paramagnetic resonance (EPR) spectroscopy were applied and adapted. The spectra recorded in the near infrared region (FT-NIR) turned out to be very useful for kinetic studies of the biopulping/biomodification processes and a good method to evaluate the capabilities of fungi to modify wood surfaces within this short period.Mikrobiološki mehanizmi razgradnje lignina, osim biološke proizvodnje pulpe tijekom koje dolazi do selektivne pretvorbe lignina, mogu se primijeniti tijekom fermentacije na krutoj podlozi. U ovom je revijalnom prikazu dan pregled istraživanja selektivne pretvorbe lignina, a osobito rad znanstvenoga tima, koji se sastoji od istraživača iz pet raznih laboratorija. Troje istraživaa surađuju u centru Wood K plus. Istraživanja te skupine bila su usmjerena na fermentaciju primjenom jedinstvenog metabolizma selektivne gljive, uzročnika bijele truleži, u razgradnji površine drveta tijekom relativno kratkog vremena fermentacije (manje od tjedan dana) i na istraživanje molekularnih mehanizama koji uzrokuju te promjene. Razgradnja lignina s pomoću selektivnih gljiva (npr. Ceriporiopsis subvermispora i vrste roda Phlebia) na površini drveta bila je značajna nakon tri dana. Nakon sedam dana ukupni udjel lignina u piljevini drva smreke smanjen je za više od 3,5 %. Gubitak lignina praćen je povećanjem količine ekstraktibilnih tvari. Da bi se pratio proces modifikacije s pomoću gljiva, primijenjene su prilagođene metode Fourier transformacijske infracrvene spektroskopije (FTIR) i elektronske paramagnetske rezonancije (EPR). Spektar snimljen blizu infracrvenog područja (FT-NIR) bio je vrlo koristan za istraživanje kinetike biološke proizvodnje pulpe odnosno procesa biomodifikacije i dobra je metoda za procjenu sposobnosti gljiva da u vrlo kratkom vremenskom roku razgrađuju površinu drveta

Dietary Silicon Deficiency Does Not Exacerbate Diet-Induced Fatty Lesions in Female ApoE Knockout Mice.

BACKGROUND: Dietary silicon has been positively linked with vascular health and protection against atherosclerotic plaque formation, but the mechanism of action is unclear. OBJECTIVES: We investigated the effect of dietary silicon on 1) serum and aorta silicon concentrations, 2) the development of aortic lesions and serum lipid concentrations, and 3) the structural and biomechanic properties of the aorta. METHODS: Two studies, of the same design, were conducted to address the above objectives. Female mice, lacking the apolipoprotein E (apoE) gene, and therefore susceptible to atherosclerosis, were separated into 3 groups of 10-15 mice, each exposed to a high-fat diet (21% wt milk fat and 1.5% wt cholesterol) but with differing concentrations of dietary silicon, namely: silicon-deprived (-Si; <3-μg silicon/g feed), silicon-replete in feed (+Si-feed; 100-μg silicon/g feed), and silicon-replete in drinking water (+Si-water; 115-μg silicon/mL) for 15-19 wk. Silicon supplementation was in the form of sodium metasilicate (feed) or monomethylsilanetriol (drinking water). RESULTS: The serum silicon concentration in the -Si group was significantly lower than in the +Si-feed (by up to 78%; P < 0.003) and the +Si-water (by up to 84%; P < 0.006) groups. The aorta silicon concentration was also lower in the -Si group than in the +Si-feed group (by 65%; P = 0.025), but not compared with the +Si-water group. There were no differences in serum and aorta silicon concentrations between the silicon-replete groups. Body weights, tissue wet weights at necropsy, and structural, biomechanic, and morphologic properties of the aorta were not affected by dietary silicon; nor were the development of fatty lesions and serum lipid concentrations. CONCLUSIONS: These findings suggest that dietary silicon has no effect on atherosclerosis development and vascular health in the apoE mouse model of diet-induced atherosclerosis, contrary to the reported findings in the cholesterol-fed rabbit model

A Novel Endothelial Damage Inhibitor Reduces Oxidative Stress and Improves Cellular Integrity in Radial Artery Grafts for Coronary Artery Bypass

The radial artery (RA) is a frequently used conduit in coronary artery bypass grafting (CABG). Endothelial injury incurred during graft harvesting promotes oxidative damage, which leads to graft disease and graft failure. We evaluated the protective effect of DuraGraft®, an endothelial damage inhibitor (EDI), on RA grafts. We further compared the protective effect of the EDI between RA grafts and saphenous vein grafts (SVG). Samples of RA (n = 10) and SVG (n = 13) from 23 patients undergoing CABG were flushed and preserved with either EDI or heparinized Ringer's lactate solution (RL). The effect of EDI vs. RL on endothelial damage was evaluated ex vivo and in vitro using histological analysis, immunofluorescence staining, Western blot, and scanning electron microscopy. EDI-treated RA grafts showed a significant reduction of endothelial and sub-endothelial damage. Lower level of reactive oxygen species (ROS) after EDI treatment was correlated with a reduction of hypoxic damage (eNOS and Caveolin-1) and significant increase of oxidation-reduction potential. Additionally, an increased expression of TGFβ, PDGFα/β, and HO-1 which are indicative for vascular protective function were observed after EDI exposure. EDI treatment preserves functionality and integrity of endothelial and intimal cells. Therefore, EDI may have the potential to reduce the occurrence of graft disease and failure in RA grafts in patients undergoing CABG

Insights from a Murine Aortic Transplantation Model

Transplant vasculopathy (TV) represents a major obstacle to long-term graft survival and correlates with severity of ischemia reperfusion injury (IRI). Donor administration of the nitric oxide synthases (NOS) co-factor tetrahydrobiopterin has been shown to prevent IRI. Herein, we analysed whether tetrahydrobiopterin is also involved in TV development. Using a fully allogeneic mismatched (BALB/c to C57BL/6) murine aortic transplantation model grafts subjected to long cold ischemia time developed severe TV with intimal hyperplasia (α-smooth muscle actin positive cells in the neointima) and endothelial activation (increased P-selectin expression). Donor pretreatment with tetrahydrobiopterin significantly minimised these changes resulting in only marginal TV development. Severe TV observed in the non-treated group was associated with increased protein oxidation and increased occurrence of endothelial NOS monomers in the aortic grafts already during graft procurement. Tetrahydrobiopterin supplementation of the donor prevented all these early oxidative changes in the graft. Non-treated allogeneic grafts without cold ischemia time and syngeneic grafts did not develop any TV. We identified early protein oxidation and impaired endothelial NOS homodimer formation as plausible mechanistic explanation for the crucial role of IRI in triggering TV in transplanted aortic grafts. Therefore, targeting endothelial NOS in the donor represents a promising strategy to minimise TV

To Be Or Not to Be: the "Smoker's Paradox" - An in-Vitro Study

Background/Aims: Clinical studies have reported a better outcome of smokers after myocardial infarction compared to non-smokers. The data are controversial, as some clinical studies did not observe this effect. The cell biological processes involved, which might account for a 'Smoker's Paradox', have not been investigated yet. Therefore, the aim was to elucidate the effect of cigarette smoke on the viability of cardiomyocytes in the context of hypoxia and reperfusion. Methods: HL-1 cells were incubated with different concentrations of cigarette smoke extract (CSE) and subjected to hypoxia/reperfusion to further evaluate influence of CSE on viability of HL-1 cells using flow cytometry analyses, Western Blot and immunofluorescence staining. Results: Incubation with CSE led to a concentration-dependent reduction in HL-1 viability. Adding hypoxia as a stressor enhanced cell death. Caspase-independent apoptosis was the observed type of cell death partly induced by P53 and apoptosis-inducing-factor. Yet a significant increase in LDH release in cardiomyocytes incubated with 4%, 8% and 16% CSE suggests necrosis with rapid DNA depletion. Interestingly, after hypoxia a decreased LDH release under lower CSE concentrations was observed. Moreover, a concentration-dependent increase in proliferation and a trend for increased ATP availability under hypoxic conditions was shown. Conclusions: The trend for less LDH release in hypoxia after low-level CSE incubation might represent a switch from necrosis to apoptosis, which in combination with the increase in metabolic activity and ATP availability might account for the 'Smoker's Paradox'. These findings could partly explain inconsistent results of previous clinical studies as the data showed strong evidence for the crucial relevance of the amount of cigarettes smoked. We are in need of future studies distinguishing between different types of smokers to finally verify or falsify the 'Smoker's Paradox'

Biotehnološka razgradnja i molekularni mehanizmi razgradnje drveta pomoću selektivnih gljiva, uzročnika bijele truleži

Microbial mechanisms of lignin degradation may be utilised for solid-state fermentations other than biopulping, during which the selective conversion of lignin is required. The current paper reviews current work into selective lignin conversion, with emphasis on the contributions made by our research group, which consists of researchers from five different laboratories. Three of them cooperate within Wood K plus. The recent research of this group has focussed on fermentations utilising the unique metabolism of selective white-rot fungi to modify wood surfaces during relatively short fermentation times of less than one week and on research into the molecular mechanisms causing these modifications. Lignin degradation by selective fungi (e.g. Ceriporiopsis subvermispora and species of the genus Phlebia) on the wood surfaces was significant after three days. After seven days the overall lignin content of spruce wood shavings was reduced by more than 3.5 %. Lignin loss was accompanied by an increase of extractable substances. To evaluate small changes and to trace the fungal modification processes, Fourier transform infrared spectroscopic (FTIR) techniques and electron paramagnetic resonance (EPR) spectroscopy were applied and adapted. The spectra recorded in the near infrared region (FT-NIR) turned out to be very useful for kinetic studies of the biopulping/biomodification processes and a good method to evaluate the capabilities of fungi to modify wood surfaces within this short period.Mikrobiološki mehanizmi razgradnje lignina, osim biološke proizvodnje pulpe tijekom koje dolazi do selektivne pretvorbe lignina, mogu se primijeniti tijekom fermentacije na krutoj podlozi. U ovom je revijalnom prikazu dan pregled istraživanja selektivne pretvorbe lignina, a osobito rad znanstvenoga tima, koji se sastoji od istraživača iz pet raznih laboratorija. Troje istraživaa surađuju u centru Wood K plus. Istraživanja te skupine bila su usmjerena na fermentaciju primjenom jedinstvenog metabolizma selektivne gljive, uzročnika bijele truleži, u razgradnji površine drveta tijekom relativno kratkog vremena fermentacije (manje od tjedan dana) i na istraživanje molekularnih mehanizama koji uzrokuju te promjene. Razgradnja lignina s pomoću selektivnih gljiva (npr. Ceriporiopsis subvermispora i vrste roda Phlebia) na površini drveta bila je značajna nakon tri dana. Nakon sedam dana ukupni udjel lignina u piljevini drva smreke smanjen je za više od 3,5 %. Gubitak lignina praćen je povećanjem količine ekstraktibilnih tvari. Da bi se pratio proces modifikacije s pomoću gljiva, primijenjene su prilagođene metode Fourier transformacijske infracrvene spektroskopije (FTIR) i elektronske paramagnetske rezonancije (EPR). Spektar snimljen blizu infracrvenog područja (FT-NIR) bio je vrlo koristan za istraživanje kinetike biološke proizvodnje pulpe odnosno procesa biomodifikacije i dobra je metoda za procjenu sposobnosti gljiva da u vrlo kratkom vremenskom roku razgrađuju površinu drveta

Dietary Silicon Deficiency Does Not Exacerbate Diet-Induced Fatty Lesions in Female ApoE Knockout Mice.

BACKGROUND: Dietary silicon has been positively linked with vascular health and protection against atherosclerotic plaque formation, but the mechanism of action is unclear. OBJECTIVES: We investigated the effect of dietary silicon on 1) serum and aorta silicon concentrations, 2) the development of aortic lesions and serum lipid concentrations, and 3) the structural and biomechanic properties of the aorta. METHODS: Two studies, of the same design, were conducted to address the above objectives. Female mice, lacking the apolipoprotein E (apoE) gene, and therefore susceptible to atherosclerosis, were separated into 3 groups of 10-15 mice, each exposed to a high-fat diet (21% wt milk fat and 1.5% wt cholesterol) but with differing concentrations of dietary silicon, namely: silicon-deprived (-Si; <3-μg silicon/g feed), silicon-replete in feed (+Si-feed; 100-μg silicon/g feed), and silicon-replete in drinking water (+Si-water; 115-μg silicon/mL) for 15-19 wk. Silicon supplementation was in the form of sodium metasilicate (feed) or monomethylsilanetriol (drinking water). RESULTS: The serum silicon concentration in the -Si group was significantly lower than in the +Si-feed (by up to 78%; P < 0.003) and the +Si-water (by up to 84%; P < 0.006) groups. The aorta silicon concentration was also lower in the -Si group than in the +Si-feed group (by 65%; P = 0.025), but not compared with the +Si-water group. There were no differences in serum and aorta silicon concentrations between the silicon-replete groups. Body weights, tissue wet weights at necropsy, and structural, biomechanic, and morphologic properties of the aorta were not affected by dietary silicon; nor were the development of fatty lesions and serum lipid concentrations. CONCLUSIONS: These findings suggest that dietary silicon has no effect on atherosclerosis development and vascular health in the apoE mouse model of diet-induced atherosclerosis, contrary to the reported findings in the cholesterol-fed rabbit model

Multivalent glycoconjugates as anti-pathogenic agents

Multivalency plays a major role in biological processes and particularly in the relationship between pathogenic microorganisms and their host that involves protein–glycan recognition. These interactions occur during the first steps of infection, for specific recognition between host and bacteria, but also at different stages of the immune response. The search for high-affinity ligands for studying such interactions involves the combination of carbohydrate head groups with different scaffolds and linkers generating multivalent glycocompounds with controlled spatial and topology parameters. By interfering with pathogen adhesion, such glycocompounds including glycopolymers, glycoclusters, glycodendrimers and glyconanoparticles have the potential to improve or replace antibiotic treatments that are now subverted by resistance. Multivalent glycoconjugates have also been used for stimulating the innate and adaptive immune systems, for example with carbohydrate-based vaccines. Bacteria present on their surfaces natural multivalent glycoconjugates such as lipopolysaccharides and S-layers that can also be exploited or targeted in anti-infectious strategie

Multivalent glycoconjugates as anti-pathogenic agents

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