Aachen, Germany
Aachen, Germany

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Niessen M.,Leibniz University of Hanover | Krause K.,Leibniz University of Hanover | Horst I.,Leibniz University of Hanover | Staebler N.,RWTH Aachen | And 9 more authors.
Journal of Experimental Botany | Year: 2012

The major photorespiratory pathway in higher plants is distributed over chloroplasts, mitochondria, and peroxisomes. In this pathway, glycolate oxidation takes place in peroxisomes. It was previously suggested that a mitochondrial glycolate dehydrogenase (GlcDH) that was conserved from green algae lacking leaf-type peroxisomes contributes to photorespiration in Arabidopsis thaliana. Here, the identification of two Arabidopsis mitochondrial alanine:glyoxylate aminotransferases (ALAATs) that link glycolate oxidation to glycine formation are described. By this reaction, the mitochondrial side pathway produces glycine from glyoxylate that can be used in the glycine decarboxylase (GCD) reaction of the major pathway. RNA interference (RNAi) suppression of mitochondrial ALAAT did not result in major changes in metabolite pools under standard conditions or enhanced photorespiratroy flux, respectively. However, RNAi lines showed reduced photorespiratory CO2 release and a lower CO2 compensation point. Mitochondria isolated from RNAi lines are incapable of converting glycolate to CO2, whereas simultaneous overexpression of GlcDH and ALAATs in transiently transformed tobacco leaves enhances glycolate conversion. Furthermore, analyses of rice mitochondria suggest that the side pathway for glycolate oxidation and glycine formation is conserved in monocotyledoneous plants. It is concluded that the photorespiratory pathway from green algae has been functionally conserved in higher plants. © 2012 The Author.


PubMed | University of Hamburg, University of Marburg, BLS Laboratories GmbH, TU Dresden and 2 more.
Type: | Journal: Journal of biomedical materials research. Part B, Applied biomaterials | Year: 2016

This study assesses the biocompatibility of novel silk protein membranes with and without modification, and evaluates their effect on facilitating bone formation and defect repair in guided bone regeneration. Two calvarian bone defects 12 mm in diameter were created in each of a total of 38 rabbits. Four different types of membranes, (silk-, hydroxyapatite-modified silk-, -TCP-modified silk- and commonly clinically used collagen-membranes) were implanted to cover one of the two defects in each animal. Histologic analysis did not show any adverse tissue reactions in any of the defect sites indicating good biocompatibility of all silk protein membranes. Histomorphometric and histologic evaluation revealed that collagen and -TCP modified silk membranes supported bone formation (collagen: bone area fraction p=0.025; significant; -TCP modified silk membranes bone area fraction: p=0.24, not significant), guided bone regeneration and defect bridging. The bone, which had formed in defects covered by -TCP modified silk membranes, displayed a more advanced stage of bone tissue maturation with restoration of the original calvarial bone microarchitecture when compared to the bone which had formed in defects, for which any of the other test membranes were used. Micro-CT analysis did not reveal any differences in the amount of bone formation between defects with and without membranes. In contrast to the collagen membranes, -TCP modified silk membranes were visible in all cases and may therefore be advantageous for further supporting bone formation beyond 10 weeks and preventing soft tissue ingrowth from the periphery. 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.


Woltje M.,Spintec Engineering GmbH | Bobel M.,Spintec Engineering GmbH | Rheinnecker M.,Spintec Engineering GmbH | Tettamanti G.,University of Insubria | And 3 more authors.
Applied Microbiology and Biotechnology | Year: 2014

The silkworm Bombyx mori represents an established in vivo system for the production of recombinant proteins. Baculoviruses have been extensively investigated and optimised for the expression of high protein levels inside the haemolymph of larvae and pupae of this lepidopteran insect. Current technology includes deletion of genes responsible for the activity of virus-borne proteases, which in wild-type viruses, cause liquefaction of the host insect and enhance horizontal transmission of newly synthesised virus particles. Besides the haemolymph, the silk gland of B. mori provides an additional expression system for recombinant proteins. In this paper, we investigated how silk gland can be efficiently infected by a Autographa californica multicapsid nuclear polyhedrosis virus (AcMNPV). We demonstrated that the viral chitinase and the cysteine protease cathepsin are necessary to permit viral entry into the silk gland cells of intrahaemocoelically infected B. mori larvae. Moreover, for the first time, we showed AcMNPV crossing the basal lamina of silk glands in B. mori larvae, and we assessed a new path of infection of silk gland cells that can be exploited for protein production. © 2014 Springer-Verlag.


Grant
Agency: Cordis | Branch: FP7 | Program: CP-TP | Phase: NMP.2013.2.2-1 | Award Amount: 5.87M | Year: 2014

Active therapeutic biodegradable and biocompatible materials are highly in demand. These are required for the production of medicinal products in a variety of areas including implant technology, tissue engineering, drug delivery and wound healing. Within implant technology such biomaterials can be used for dental, bone and cardiovascular implants. Tailored mechanical properties, biocompatibility and degradation rate is the key to the development for a specific implant. Stents are tubular type implants that are deployed most commonly to recover the shape of narrowed arterial segments. Although, the clinical use of stents is widespread, they cause adverse responses including inflammation, in-stent restenosis and thrombosis. Endothelialisation of the stent greatly reduces these adverse reactions. In contrast to permanent stents there is great attraction in the notion of a biodegradable stent that recovers and maintains arterial shape and then gradually disappears and avoids further complications. In this multi-institution & disciplinary SME focussed project we will aim to provide the technological framework that leads to the production of reinforced polymeric biomaterials tailored towards stent manufacturing without adverse effects. Both natural and synthetic polymers will be produced and used. These will be reinforced and functionalised using a variety of techniques. Controlled delivery of suitable positive additives including antimitotic factors will be aimed for and their release monitored. These highly functionalised active biomaterials will be characterised thoroughly for material properties, biocompatibility, rate of biodegradation and used for the production of ideal stents. These will be characterized thoroughly leading to preclinical validation. All required production and manufacturing guidelines will be followed.


PubMed | Spintec Engineering GmbH and University of Hamburg
Type: Journal Article | Journal: Oral surgery, oral medicine, oral pathology and oral radiology | Year: 2016

To evaluate a novel microvascular anastomosis technique using N-fibroin stents.Cylinder stents of 1mm diameter and 5mm length were fabricated using N-fibroin from silkworms. In 22 rats, aortas were dissected, and the stent was inserted into the two ends of the aorta and fixed using methylmethacrylate.Stent anastomosis was successful in 21 (96%) rats. The mean ischemia time was 7.4minutes, significantly shorter than the 15.9minutes in the control group with conventional sutures (P<.0001). After 4months, anastomosis was functionally patent in all cases. However, elastic fibers remained interrupted in all stent anastomosis cases, and marked host rejection was evident at the stent anastomosis sites. Around the stents, thrombi were frequent (52%).Our study demonstrated the basic feasibility of stent anastomosis using N-fibroin stents and reduced ischemia time. However, thrombus formation, frequent and severe abdominal infections, and heavy host rejection remain critical issues.


A silk medical device is described, which is useful for the treatment of wounds to prevent infection. The silk medical device is manufactured from a silk protein material that is loaded with a polymeric cationic antimicrobial, such as polyhexamethylene biguanide (PHMB).


Patent
Spintec Engineering GmbH | Date: 2014-04-16

The invention relates to a device and kit for introducing at least one physiologically active compound into an organ or cavity of a human or animal body. The device comprises at least one silk material and is loaded with the physiologically active compound, wherein the silk material comprises at least one cleavage site that is cleavable by at least one degrading agent. For example, the incorporation of cleavage sites 10 in the form of thinner regions compared to a ring-shaped silk material 20 allows for controlled destruction of the silk material into smaller elements 30.


A method and an apparatus (20) for the manufacture of a single silk mono filament (60). The single silk mono filament (60) has a tensile strength of above 40 Ncwtons. The single silk mono filament (60) has applications as a musical string or a medical device.


Patent
Spintec Engineering Gmbh | Date: 2011-01-20

A method for the extrusion of a silk fibre from a water-soluble material which comprises providing the water-soluble material (25) in a liquid form, extruding the water-soluble material (25) through an opening (40) to form a precursor of the extruded silk fibre (53) and receiving the precursor on a moving surface (50). The precursor is treated on the moving surface (50) to form the silk fibre.


A silk medical device (60). The silk medical device (60) is manufactured from a silk protein material (15) which is loaded with a polymeric cationic antimicrobial (55). The polymeric cationic antimicrobial (55) is polyhexamethylene biguanide (PHMB). The silk medical device (60) is used for the treatment of wounds (70) to prevent infection.

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