Tension Fields in Originally Curved, Thin Sheets During Shearing Stresses

The analysis of the stresses in the sheet and stiffeners is predicated upon the direction of the wrinkles, particularly the tensile stresses (principal stresses). This analysis and the calculation of stresses after buckling form the subject of the present article. It includes: 1) metal cylinders with closely spaced longitudinal stiffeners; 2) metal cylinders with closely spaced transverse rings

Transcriptome analysis of a phenol-producing Pseudomonas putida S12 construct: Genetic and physiological basis for improved production

The unknown genetic basis for improved phenol production by a recombinant Pseudomonas putida S12 derivative bearing the tpl (tyrosine-phenol lyase) gene was investigated via comparative transcriptomics, nucleotide sequence analysis, and targeted gene disruption. We show upregulation of tyrosine biosynthetic genes and possibly decreased biosynthesis of tryptophan caused by a mutation in the trpE gene as the genetic basis for the enhanced phenol production. In addition, several genes in degradation routes connected to the tyrosine biosynthetic pathway were upregulated. This either may be a side effect that negatively affects phenol production or may point to intracellular accumulation of tyrosine or its intermediates. A number of genes identified by the transcriptome analysis were selected for targeted disruption in P. putida S12TPL3. Physiological and biochemical examination of P. putida S12TPL3 and these mutants led to the conclusion that the metabolic flux toward tyrosine in P. putida S12TPL3 was improved to such an extent that the heterologous tyrosine-phenol lyase enzyme had become the rate-limiting step in phenol biosynthesis. Copyright © 2008, American Society for Microbiology. All Rights Reserved

Comparative transcriptomics and proteomics of p-hydroxybenzoate producing Pseudomonas putida S12: novel responses and implications for strain improvement

A transcriptomics and proteomics approach was employed to study the expression changes associated with p-hydroxybenzoate production by the engineered Pseudomonas putida strain S12palB1. To establish p-hydroxybenzoate production, phenylalanine-tyrosine ammonia lyase (pal/tal) was introduced to connect the tyrosine biosynthetic and p-coumarate degradation pathways. In agreement with the efficient p-hydroxybenzoate production, the tyrosine biosynthetic and p-coumarate catabolic pathways were upregulated. Also many transporters were differentially expressed, one of which—a previously uncharacterized multidrug efflux transporter with locus tags PP1271-PP1273—was found to be associated with p-hydroxybenzoate export. In addition to tyrosine biosynthesis, also tyrosine degradative pathways were upregulated. Eliminating the most prominent of these resulted in a 22% p-hydroxybenzoate yield improvement. Remarkably, the upregulation of genes contributing to p-hydroxybenzoate formation was much higher in glucose than in glycerol-cultured cells

NACA Technical Memorandums

The analysis of the stresses in the sheet and stiffeners is predicated upon the direction of the wrinkles, particularly the tensile stresses (principal stresses). This analysis and the calculation of stresses after buckling form the subject of the present article. It includes: 1) metal cylinders with closely spaced longitudinal stiffeners; 2) metal cylinders with closely spaced transverse rings

Bioremediation of BTEX hydrocarbons: Effect of soil inoculation with the toluenegrowing fungus Cladophialophora sp strain T1

The biodegradation of a mixture of benzene, toluene, ethylbenzene, xylene, (BTEX) and methyl-tert-butyl ether (MTBE) was studied in soil microcosms. Soil inoculation with the toluene-metabolising fungusCladophialophora sp. strain T1 was evaluated in sterile and non-sterile soil. Induction of biodegradation capacity following BTEX addition was faster in the soil native microflora than in axenic soil cultures of the fungus. Toluene, ethylbenzenes, and the xylenes were metabolized by the fungus but biodegradation of benzene required the activity of the indigenous soil microorganisms. MTBE was not biodegraded under the tested environmental conditions. Biodegradation profiles were also examined under two pH conditions after a long term exposure to BTEX. At neutral conditions the presence of the fungus had little effect on the intrinsic soil biodegradation capacity. At an acidic pH, however, the activity of the indigenous degraders was inhibited and the presence of Cladophialophora sp. increased significantly the biodegradation rates of toluene and ethylbenzene. Comparison of the BTEX biodegradation rates measured in soil batches combining presence and absence of indigenous degraders and the fungal inoculum indicated that no severe antagonism occurred between the indigenous bacteria and Cladophialophora sp. The presence of the fungal inoculum at the end of the experiments was confirmed by PCR-TGGE analysis of small subunits of 18S rDN

Anaerobic oxidation of 2-chloroethanol under denitrifying conditions by Pseudomonas stutzeri

A bacterium that uses 2-chloroethanol as sole energy and carbon source coupled to denitrification was isolated from 1,2-dichloroethane-contaminated soil. Its 16 S rDNA sequence showed 98% similarity with the type strain of Pseudomonas stutzeri (DSM 5190) and the isolate was tentatively identified as Pseudomonas stutzeri strain JJ. Strain JJ oxidized 2-chloroethanol completely to CO2 with NO3- or O-2 as electron acceptor, with a preference for O-2 if supplied in combination. Optimum growth on 2-chloroethanol with nitrate occurred at 30 degreesC with a mu(max) of 0.14 h(-1) and a yield of 4.4 g protein per mol 2-chloroethanol metabolized. Under aerobic conditions, the mu(max) was 0.31 h(-1). NO2- also served as electron acceptor, but reduction of Fe(OH)(3), MnO2, SO42-, fumarate or ClO3- was not observed. Another chlorinated compound used as sole energy and carbon source under aerobic and denitrifying conditions was chloroacetate. Various different bacterial strains, including some closely related Pseudomonas stutzeri strains, were tested for their ability to grow on 2-chloroethanol as sole energy and carbon source under aerobic and denitrifying conditions, respectively. Only three strains, Pseudomonas stutzeri strain LMD 76.42, Pseudomonas putida US2 and Xanthobacter autotrophicus GJ10, grew aerobically on 2-chloroethanol. This is the first report of oxidation of 2-chloroethanol under denitrifying conditions by a pure bacterial culture

A Comparative Analysis of Equine Mesenchymal Stromal Cells and Dermal Fibroblasts

The aim of this study was to isolate and characterise equine mesenchymal stromal cells from various sources and to compare their biological properties to that of dermal fibroblasts. By using multiple conventional methods a comparative analysis of the different populations could be made. The results showed that little distinguishes mesenchymal stromal cells from dermal fibroblasts, they have the same morphology and growth characteristics, the same cell surface markers as demonstrated with immunocytochemistry and flow cytometry and the capacity to undergo trilineage differentiation into adipo-, chondro- and osteogenic lineages essentially becoming fat, cartilage and bone. An allogenic synovial fluid model was shown to induce a chondrogenic phenotype in equine mesenchymal stromal cells as well as dermal fibroblasts. A bio-activation assay was performed to evaluate cytokine production of cell populations after activation with Tumour necrosis factor alpha or inflammatory synovial fluid. All of the analysed cell populations demonstrated up-regulation of production of the anti-inflammatory cytokines IL-10 and TGF-β1, after activation with inflammatory synovial fluid, although significant values could not be obtained for every source. As for Prostaglandin E2, results were obtained for bone marrow stromal cells and dermal fibroblasts populations only. Their effects were in opposite; dermal fibroblast reduced the production of Prostaglandin E2 post activation. A functional bio-activation assay has shown promise as a method to distinguish equine mesenchymal stromal cells from dermal fibroblast populations