Here, we studied the potential role of inorganic polyphosphate (polyP) as an energy source for ADP and ATP formation in the extracellular space. In SaOS-2 cells, we show that matrix vesicles are ...released into the extracellular space after incubation with polyP. These vesicles contain both alkaline phosphatase (ALP) and adenylate kinase (AK) activities (mediated by ALPL and AK1 enzymes). Both enzymes translocate to the cell membrane in response to polyP. To distinguish the process(es) of AMP and ADP formation during ALP hydrolysis from the ATP generated via the AK reaction, inhibition studies with the AK inhibitor A(5')P5(5')A were performed. We found that ADP formation in the extracellular space occurs after enzymatic ATP synthesis. After exposure to polyP, a significant increase of the ADP level was observed, which is likely to be been catalyzed by ALP. This increase is not due to an intensified ATP release via exocytosis. The ATP level in the extracellular space of SaOS-2 cells is strongly increased in response to polyP, very likely mediated by the AK. We propose that the ALP and AK enzymes are involved in the extracellular ADP and ATP synthesis.
We investigated the effect of bioglass (bioactive glass) on growth and mineralization of bone-related SaOS-2 cells, encapsulated into a printable and biodegradable alginate/gelatine hydrogel. The ...hydrogel was supplemented either with polyphosphate (polyP), administered as polyP • Ca2+-complex, or silica, or as biosilica that had been enzymatically prepared from ortho-silicate by silicatein. These hydrogels, together with SaOS-2 cells, were bioprinted to computer-designed scaffolds. The results revealed that bioglass (nano)particles, with a size of 55 nm and a molar ratio of SiO2 : CaO : P2O5 of 55 : 40 : 5, did not affect the growth of the encapsulated cells. If silica, biosilica, or polyP • Ca2+-complex is co-added to the cell-containing alginate/gelatin hydrogel the growth behavior of the cells is not changed. Addition of 5 mg/ml of bioglass particles to this hydrogel significantly enhanced the potency of the entrapped SaOS-2 cells to mineralize. If compared with the extent of the cells to form mineral deposits in the absence of bioglass, the cells exposed to bioglass together with 100 µmoles/L polyP • Ca2+-complex increased their mineralization activity from 2.1- to 3.9-fold, or with 50 µmoles/L silica from 1.8- to 2.9-fold, or with 50 µmoles/L biosilica from 2.7- to 4.8-fold or with the two components together (100 µmoles/L polyP • Ca2+-complex and 50 µmoles/L biosilica) from 4.1- to 6.8-fold. Element analysis by EDX spectrometry of the mineral nodules formed by SaOS-2 revealed an accumulation of O, P, Ca and C, indicating that the mineral deposits contain, besides Ca-phosphate also Ca-carbonate. The results show that bioglass added to alginate/gelatin hydrogel increases the proliferation and mineralization of bioprinted SaOS-2 cells. We conclude that the development of cell-containing scaffolds consisting of a bioprintable, solid and cell-compatible inner matrix surrounded by a printable hard and flexible outer matrix containing bioglass, provide a suitable strategy for the fabrication of morphogenetically active and biodegradable implants.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Inorganic polyphosphates (polyP) consist of linear chains of orthophosphate residues, linked by high-energy phosphoanhydride bonds. They are evolutionarily old biopolymers that are present from ...bacteria to man. No other molecule concentrates as much (bio)chemically usable energy as polyP. However, the function and metabolism of this long-neglected polymer are scarcely known, especially in higher eukaryotes. In recent years, interest in polyP experienced a renaissance, beginning with the discovery of polyP as phosphate source in bone mineralization. Later, two discoveries placed polyP into the focus of regenerative medicine applications. First, polyP shows morphogenetic activity, i.e., induces cell differentiation via gene induction, and, second, acts as an energy storage and donor in the extracellular space. Studies on acidocalcisomes and mitochondria provided first insights into the enzymatic basis of eukaryotic polyP formation. In addition, a concerted action of alkaline phosphatase and adenylate kinase proved crucial for ADP/ATP generation from polyP. PolyP added extracellularly to mammalian cells resulted in a 3-fold increase of ATP. The importance and mechanism of this phosphotransfer reaction for energy-consuming processes in the extracellular matrix are discussed. This review aims to give a critical overview about the formation and function of this unique polymer that is capable of storing (bio)chemically useful energy.
An examination of marine organisms with disulfide- and multisulfide-containing metabolites is presented. Polysulfides from various marine organisms exhibit different biological activities.
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•A comprehensive review on phthalocyanines (Pc) in important applications.•Targeting chemical sensors, non-linear optics (NLO), and energy storage technologies.•Review focuses on ...recent advances (2014–2020) of phthalocyanines.•Perspectives for huge research opportunities are highlighted.
Phthalocyanines (Pcs) are intensely coloured, robust macrocycles that possess admirable chemical, thermal and photo- stability as a result of its extensive π-network. The Pc family has established their fundamental and technological importance in numerous applications due to structural versatility and unique properties that result from the incorporation of a variety of inorganic and organic components into its framework. The diversity of Pc structures allows for the optimisation of certain properties to obtain functional, high-performance materials. The combination of aromaticity, relatively simple synthesis and structural flexibility makes Pcs a great asset for numerous scientific and industrial advancements. This review focuses on recent advances (2014–2020) of phthalocyanines in the specific technologies of chemical sensors, non-linear optics (NLO), and energy storage applications. Many MPc complexes reported to date favour select metals and ligand derivatives which leaves huge opportunities for further exploration.
Recent developments in the field of biomaterials for tissue engineering open up new opportunities for regenerative therapy and prevention of progression of osteo-articular damage/impairment. A key ...advancement was the discovery of the regenerative activity of a group of physiologically occurring high-energy polymers, inorganic polyphosphates (polyP). These bio-polymers, in suitable bioinspired formulations, turned out to be capable of inducing proliferation and differentiation of mesenchymal stem cells into osteogenic or chondrogenic lineages through differential gene expression (morphogenetic activity). Unprecedented is the property of these biopolymers to deliver high-energy phosphate in the extracellular space to promote anabolic processes including extracellular matrix synthesis in bradytrophic tissues such as cartilage and mineralized bone. This review summarizes the biological effects of these unique bio-polymers, not yet met by other biomaterials and depending on their specific formulation as smart amorphous nanoparticles/microparticles with different counterions. In addition, polyP in combination with other, hydrogel-forming polymers provides the basis for the fabrication of hardenable bio-inks applicable in additive manufacturing/3D printing and 3D cell bioprinting of regeneratively active patient-specific osteo-articular implants. The future prospects of this innovative technology are discussed.
Physiological amorphous polyphosphate nano/micro-particles, injectable and implantable, attract and stimulate MSCs into implants for tissue regeneration.
A clear picture of animal relationships is a prerequisite to understand how the morphological and ecological diversity of animals evolved over time. Among others, the placement of the acoelomorph ...flatworms, Acoela and Nemertodermatida, has fundamental implications for the origin and evolution of various animal organ systems. Their position, however, has been inconsistent in phylogenetic studies using one or several genes. Furthermore, Acoela has been among the least stable taxa in recent animal phylogenomic analyses, which simultaneously examine many genes from many species, while Nemertodermatida has not been sampled in any phylogenomic study. New sequence data are presented here from organisms targeted for their instability or lack of representation in prior analyses, and are analysed in combination with other publicly available data. We also designed new automated explicit methods for identifying and selecting common genes across different species, and developed highly optimized supercomputing tools to reconstruct relationships from gene sequences. The results of the work corroborate several recently established findings about animal relationships and provide new support for the placement of other groups. These new data and methods strongly uphold previous suggestions that Acoelomorpha is sister clade to all other bilaterian animals, find diminishing evidence for the placement of the enigmatic Xenoturbella within Deuterostomia, and place Cycliophora with Entoprocta and Ectoprocta. The work highlights the implications that these arrangements have for metazoan evolution and permits a clearer picture of ancestral morphologies and life histories in the deep past.
V2O5 nanowires exhibit an intrinsic catalytic activity towards classical peroxidase substrates such as 2,2‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) and 3,3,5,5,‐tetramethylbenzdine ...(TMB) in the presence of H2O2. These V2O5 nanowires show an optimum reactivity at a pH of 4.0 and the catalytic activity is dependent on the concentration. The Michaelis‐Menten kinetics of the ABTS oxidation over these nanowires reveals a behavior similar to that of their natural vanadium‐dependent haloperoxidase (V‐HPO) counterparts. The V2O5 nanowires mediate the oxidation of ABTS in the presence of H2O2 with a turnover frequency (kcat) of 2.5 × 103 s−1. The KM values of the V2O5 nanowires for ABTS oxidation (0.4 μM) and for H2O2 (2.9 μM) at a pH of 4.0 are significantly smaller than those reported for horseradish peroxidases (HRP) and V‐HPO indicating a higher affinity of the substrates for the V2O5 nanowire surface. Based on the kinetic parameters and similarity with vanadium‐based complexes a mechanism is proposed where an intermediate metastable peroxo complex is formed as the first catalytic step. The nanostructured vanadium‐based material can be re‐used up to 10 times and retains its catalytic activity in a wide range of organic solvents (up to 90%) making it a promising mimic of peroxidase catalysts.
V2O5 nanowires show an intrinsic catalytic activity towards classical peroxidase of substrates such as 2,2‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) and 3,3,5,5,‐tetramethylbenzadine (TMB) in the presence of H2O2. The Michaelis–Menten kinetics of the ABTS oxidation over these nanowires reveal behavior that is similar to that of their natural vanadium‐dependent haloperoxidase (V‐HPO) counterparts. The nanostructured vanadium‐based material can be re‐used up to 10 times and retains its catalytic activity making it a promising mimic of peroxidase catalysts.
Recently two approaches were reported that addressed a vitally important problem in regenerative medicine, i. e. the successful treatment of wounds even under diabetic conditions. Accordingly, these ...studies with diabetic rabbits Sarojini et al. PLoS One 2017, 12(4):e0174899 and diabetic mice Müller et al. Polymers 2017, 9, 300 identified a novel (potential) target for the acceleration of wound healing in diabetes. Both studies propose a raise of the intracellular metabolic energy status via exogenous administration either of ATP, encapsulated into lipid vesicles, or of polyphosphate (polyP) micro-/nanoparticles. Recently this physiological polymer, polyP, was found to release metabolic energy in form of ATP into both the extra- and also intra-cellular space. In the present work the uptake mechanism of the amorphous polyP microparticles "Ca-polyP-MP" has been described and found to be a clathrin-dependent endocytosis import, based on inhibition studies with the inhibitor trifluoperazine, which blocks the clathrin-dependent endocytosis import. The experiments had been performed with SaOS-2 cells, by studying the uptake and distribution of the electron-dense particles into the cells, and with HUVEC cells, for analysis of the intracellular accumulation of polyP, visualized by fluorescent staining of polyP. Concurrently with the uptake of particular polyP the intracellular ATP level increased as well. In contrast to "Ca-polyP-MP" the soluble polyP, administered as "Na-polyPCa2+", did not cause an increase in the intracellular Ca2+ level, suggesting a different mode of action of these two forms of polyP. Based on existing data on the effect of polyP and ATP on the induction of vascularization during wound repair, both groups (Sarojini et al. and Müller et al.) propose that the acceleration of wound repair is based on an increased metabolic energy supply directly to the regenerating wound area.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Silicatein-α is responsible for the biomineralization of silicates in sponges. We used silicatein-α to guide the self-assembly of calcite "spicules" similar to the spicules of the calcareous sponge ...Sycon sp. The self-assembled spicules, 10 to 300 micrometers (μm) in length and 5 to 10 μm in diameter, are composed of aligned calcite nanocrystals. The spicules are initially amorphous but transform into calcite within months, exhibiting unusual growth along 100. They scatter x-rays like twinned calcite crystals. Whereas natural spicules evidence brittle failure, the synthetic spicules show an elastic response, which greatly enhances bending strength. This remarkable feature is linked to a high protein content. With nano-thermogravimetric analysis, we measured the organic content of a single spicule to be 10 to 16%. In addition, the spicules exhibit waveguiding properties even when they are bent.
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