The in vivo healing process of vascular grafts involves the interaction of many contributing factors. The ability of vascular grafts to provide an environment which allows successful accomplishment of this process is extremely difficult. Poor endothelisation, inflammation, infection, occlusion, thrombosis, hyperplasia and pseudoaneurysms are common issues with synthetic grafts in vivo. Advanced materials composed of decellularised extracellular matrices (ECM) have been shown to promote the healing process via modulation of the host immune response, resistance to bacterial infections, allowing re-innervation and reestablishing homeostasis in the healing region. The physiological balance within the newly developed vascular tissue is maintained via the recreation of correct biorheology and mechanotransduction factors including host immune response, infection control, homing and the attraction of progenitor cells and infiltration by host tissue. Here, we review the progress in this tissue engineering approach, the enhancement potential of ECM materials and future prospects to reach the clinical environment.
A novel R391-like ICE (integrating conjugative element) has been detected in the 4.2 MB genome of Shewanella putrefaciens W3-18-1 located on three different contigs. Assembly of the ICE encoding contigs based on similarity with R391 revealed a mosaic element of plasmid, phage and transposon-like sequences typical of SXT/R391 ICE-like elements. The element, which is 110 057 bp in length, was highly similar to R391 sequences, with most related ORFs showing >96% amino acid sequence identity. The element, designated ICESpuPO1, contained a number of inserts determining resistance to copper and other heavy metals and a broad-spectrum RND efflux pump similar to antibiotic efflux systems. The element was integrated into the Shewanella prfC gene in a manner similar to related ICE-like elements. The chromosomal element junctions contained a 17-bp SXT/R391-like attL and attR site and an unannotated ORF between attL and the ICE integrase encoding a putative recombinational directional factor necessary for excision, with 100% amino acid identity to the R391 ORF4 product.
Molecular analysis of the bacterial community structure associated with sludge processed by autothermal thermophilic aerobic digestion (ATAD), was performed using a number of extraction and amplification procedures which differed in yield, integrity, ability to amplify extracted templates and specificity in recovering species present. Interference to PCR and qPCR amplification was observed due to chelation, nuclease activity and the presence of thermolabile components derived from the ATAD sludge. Addition of selected adjuvant restored the ability to amplify community DNA, derived from the thermophilic sludge, via a number of primer sets of ecological importance and various DNA polymerases. Resolution of community profiles by molecular techniques was also influenced by the ATAD sludge extraction procedure as demonstrated by PCR-DGGE profiling and comparison of taxonomic affiliations of the most predominant members within 16S rRNA gene libraries constructed from ATAD DNA extracted by different methods. Several modifications have been shown to be necessary to optimize the molecular analysis of the ATAD thermal niche which may have general applicability to diversity recovery from similar environments.
OPEN ACCESSDiversity 2010, 2 506
The potential suitability of 10 commercial protease and lipase products for cleaning-in-place (CIP) application in the dairy industry was investigated on a laboratory scale. Assessment was based primarily on the ability of the enzymes to remove an experimentally generated milk fouling deposit from stainless steel (SS) panels. Three protease products were identified as being most suitable for this application on the basis of their cleaning performance at 40 °C, which was comparable to that of the commonly used cleaning agent, 1% NaOH at 60 °C. This was judged by quantification of residual organic matter and protein on the SS surface after cleaning and analysis by laser scanning confocal microscopy (LSCM). Enzyme activity was removed/inactivated under conditions simulating those normally undertaken after cleaning (rinsing with water, acid circulation, sanitation). Preliminary process-scale studies strongly suggest that enzyme-based CIP achieves satisfactory cleaning at an industrial scale. Cost analysis indicates that replacing caustic-based cleaning procedures with biodegradable enzymes operating at lower temperatures would be economically viable. Additional potential benefits include decreased energy and water consumption, improved safety, reduced waste generation, greater compatibility with wastewater treatment processes and a reduction in the environmental impact of the cleaning process.
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