Dispersal of human and plant pathogens biofilms via nitric oxide donors at 4°C

Recent studies suggest that nitric oxide donors capable of manipulating nitric oxide-mediated signaling in bacteria could induce dispersal of biofilms. Encased in extracellular polymeric substances, human and plant pathogens within biofilms are significantly more resistant to sanitizers. This is particularly a problem in refrigerated environments where food is processed. In an exercise aimed to study the potential of nitric oxide donors as biofilm dispersal in refrigerated conditions, we compared the ability of different nitric oxide donors (SNAP, NO-aspirin and Noc-5) to dislodge biofilms formed by foodborne, human and plant pathogens treated at 4 °C. The donors SNAP and Noc-5 were efficient in dispersing biofilms formed by Salmonella enterica, pathogenic Escherichia coli and Listeria innocua. The biomasses were decreased up to 30 % when compared with the untreated controls. When the plant pathogens Pectobacterium sp. and Xanthomonas sp. were tested the dispersion was mainly limited to Pectobacterium carotovorum biofilms, decreasing up to 15 % after exposure to molsidomine. Finally, the association of selected nitric oxide donors with sanitizers (DiQuat, H2O2, peracetic acid and PhenoTek II) was effective in dispersing biofilms. The best dispersal was achieved by pre-treating P. carotovorum with molsidomine and then peracetic acid. The synergistic effect was estimated up to ~35 % in dispersal when compared with peracetic acid alone. The association of nitric oxide donors with sanitizers could provide a foundation for an improved sanitization procedure for cleaning refrigerate environments

Genomic variation in myeloma: design, content, and initial application of the Bank On A Cure SNP Panel to detect associations with progression-free survival

<p>Abstract</p> <p>Background</p> <p>We have engaged in an international program designated the <it>Bank On A Cure</it>, which has established DNA banks from multiple cooperative and institutional clinical trials, and a platform for examining the association of genetic variations with disease risk and outcomes in multiple myeloma.</p> <p>We describe the development and content of a novel custom SNP panel that contains 3404 SNPs in 983 genes, representing cellular functions and pathways that may influence disease severity at diagnosis, toxicity, progression or other treatment outcomes. A systematic search of national databases was used to identify non-synonymous coding SNPs and SNPs within transcriptional regulatory regions. To explore SNP associations with PFS we compared SNP profiles of short term (less than 1 year, <it>n </it>= 70) versus long term progression-free survivors (greater than 3 years, <it>n </it>= 73) in two phase III clinical trials.</p> <p>Results</p> <p>Quality controls were established, demonstrating an accurate and robust screening panel for genetic variations, and some initial racial comparisons of allelic variation were done. A variety of analytical approaches, including machine learning tools for data mining and recursive partitioning analyses, demonstrated predictive value of the SNP panel in survival. While the entire SNP panel showed genotype predictive association with PFS, some SNP subsets were identified within drug response, cellular signaling and cell cycle genes.</p> <p>Conclusion</p> <p>A targeted gene approach was undertaken to develop an SNP panel that can test for associations with clinical outcomes in myeloma. The initial analysis provided some predictive power, demonstrating that genetic variations in the myeloma patient population may influence PFS.</p

Eliminating acetate formation improves citramalate production by metabolically engineered Escherichia coli

Abstract Background Citramalate, a chemical precursor to the industrially important methacrylic acid (MAA), can be synthesized using Escherichia coli overexpressing citramalate synthase (cimA gene). Deletion of gltA encoding citrate synthase and leuC encoding 3-isopropylmalate dehydratase were critical to achieving high citramalate yields. Acetate is an undesirable by-product potentially formed from pyruvate and acetyl-CoA, the precursors of citramalate during aerobic growth of E. coli. This study investigated strategies to minimize acetate and maximize citramalate production in E. coli mutants expressing the cimA gene. Results Key knockouts that minimized acetate formation included acetate kinase (ackA), phosphotransacetylase (pta), and in particular pyruvate oxidase (poxB). Deletion of glucose 6-phosphate dehydrogenase (zwf) and ATP synthase (atpFH) aimed at improving glycolytic flux negatively impacted cell growth and citramalate accumulation in shake flasks. In a repetitive fed-batch process, E. coli gltA leuC ackA-pta poxB overexpressing cimA generated 54.1 g/L citramalate with a yield of 0.64 g/g glucose (78% of theoretical maximum yield), and only 1.4 g/L acetate in 87 h. Conclusions This study identified the gene deletions critical to reducing acetate accumulation during aerobic growth and citramalate production in metabolically engineered E. coli strains. The citramalate yield and final titer relative to acetate at the end of the fed-batch process are the highest reported to date (a mass ratio of citramalate to acetate of nearly 40) without being detrimental to citramalate productivity, significantly improving a potential process for the production of this five-carbon chemical

Conservation of the vendace (Coregonus albula), the U.K.'s rarest freshwater fish

Although also formerly present in two lochs in South West Scotland, populations of vendace (Coregonus albula) were until recently believed to persist in only two U.K. lakes, i.e., Bassenthwaite Lake and Derwent Water in North West England. However, although Derwent Water has retained its natural mesotrophic conditions and the status of its vendace population is acceptable, monitoring at Bassenthwaite Lake has failed to record any specimens since 2000 and the species has recently been declared locally extinct. Bassenthwaite Lake has experienced increasing problems from eutrophication, sedimentation and the introduction of fi sh species including roach (Rutilus rutilus) and ruffe (Gymnocephalus cernuus), both of which have more recently also been introduced to Derwent Water and give concern over possible food competition and egg predation. In addition to monitoring, considerable efforts have been made in recent years to conserve vendace through the protection and improvement of their habitats and the establishment of refuge populations. The latter has resulted in the establishment of a population originating from Bassenthwaite Lake in Loch Skeen of South West Scotland, with further attempts still in progress at two other sites. Public awareness of the conservation of this species, which is the U.K.'s rarest freshwater fish, has also been actively promoted