Effects of pre-existing hydrogen to stress triaxiality and damage evolution on ultra high strength steel

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Risk factors of ocular involvement in children with mitochondrial respiratory chain complex defect

PurposeMitochondrial dysfunction can present with various symptoms depending on the organ it has affected. This research tried to analyze the ophthalmologic symptoms and ophthalmologic examination (OE) results in patients with mitochondrial disease (MD).MethodsSeventy-four patients diagnosed with mitochondrial respiratory chain complex defect with biochemical enzyme assay were included in the study. They were divided into 2 groups based on the OE results by funduscopy and were analyzed on the basis of their clinical features, biochemical test results, morphological analysis, and neuroimaging findings.ResultsThirty-seven (50%) of the 74 MD patients developed ophthalmologic symptoms. Abnormal findings were observed in 36 (48.6%) patients during an OE, and 16 (21.6%) of them had no ocular symptoms. Significantly higher rates of prematurity, clinical history of epilepsy or frequent apnea events, abnormal light microscopic findings in muscle pathology, diffuse cerebral atrophy in magnetic resonance imaging, and brainstem hyperintensity and lactate peaks in magnetic resonance spectroscopy were noted in the group with abnormal OE results.ConclusionAlthough the ophthalmologic symptoms are not very remarkable in MD patients, an OE is required. When the risk factors mentioned above are observed, a more active approach should be taken in the OE because a higher frequency of ocular involvement can be expected

Characterization of diverse natural variants of CYP102A1 found within a species of Bacillus megaterium

An extreme diversity of substrates and catalytic reactions of cytochrome P450 (P450) enzymes is considered to be the consequence of evolutionary adaptation driven by different metabolic or environmental demands. Here we report the presence of numerous natural variants of P450 BM3 (CYP102A1) within a species of Bacillus megaterium. Extensive amino acid substitutions (up to 5% of the total 1049 amino acid residues) were identified from the variants. Phylogenetic analyses suggest that this P450 gene evolve more rapidly than the rRNA gene locus. It was found that key catalytic residues in the substrate channel and active site are retained. Although there were no apparent variations in hydroxylation activity towards myristic acid (C14) and palmitic acid (C16), the hydroxylation rates of lauric acid (C12) by the variants varied in the range of >25-fold. Interestingly, catalytic activities of the variants are promiscuous towards non-natural substrates including human P450 substrates. It can be suggested that CYP102A1 variants can acquire new catalytic activities through site-specific mutations distal to the active site

Prevalence and risk factors of Helicobacter pylori infection in Korea: Nationwide multicenter study over 13 years

Background : The aim of this study was to evaluate the time trend of seropositivity of Helicobacter pylori (H. pylori) over the period of 13 years in an asymptomatic Korean population, and investigate associated risk factors. Methods : This cross-sectional nationwide multicentre study surveyed anti-H. pylori IgG antibodies in 19,272 health check-up subjects (aged [greater than and equal to]16 years) in 2011. Risk factors for H. pylori infection were investigated using logistic regression. Seropositivity in asymptomatic subjects without H. pylori eradication was compared between the years 1998 and 2005. Birth cohort effects were also evaluated. Results : After exclusion of subjects with a history of H. pylori eradication therapy (n = 3,712, 19.3%) and gastric symptoms (n = 4,764, 24.7%), the seroprevalence of H. pylori infection was 54.4% in 10,796 subjects. This was significantly lower than the seroprevalence of 59.6% in 2005 and that of 66.9% in 1998, and this decrease of seropositivity of H. pylori became widespread across all ages and in most areas of the country. This decreasing trend could be explained by cohort analysis. All younger birth cohorts had a lower seroprevalence of H. pylori than older birth cohorts at the same age. Decreased seroprevalence within the same birth cohorts also accounted for this phenomenon. Clinical risk factors of H. pylori infection were higher cholesterol level ([greater than and equal to] 240 mg/dl) (OR = 1.33; 95% CI = 1.14-1.54), male gender, older age, low income, and residence in a rural area. Conclusions : A decreasing trend of H. pylori seroprevalence due to a birth cohort effect requires further studies on its related human host factors as well as socio-economic and hygienic factors. In addition, the relationship between H. pylori infection and high cholesterol level needs more investigation regarding underlying pathogenesis.This work was supported by the National Research Foundation of Korea (NRF) grant for the Global Core Research Center (GCRC) funded by the Korea government (MSIP) (No. 2011-0030001)Peer Reviewe

2013 Annual Interior Detail

ANNUAL INTERIOR DETAIL introduces recent detail works of Korean interior designs. This series\u27 new edition with full description of detailed architectural drawings makes it different from other interior books with all photos but no details. Total 70 works are categorized according to their uses; Cafe·Restaurant / Club·Lounge·Hotel / Culture·Education·Housing / Commerce / Office·Showroom / Clinic. In detail, sorting by function and area of buildings is also possible. This composition will help you easily access what you are trying to find with more concrete and detailed information of selected interior design

Display of a thermostable lipase on the surface of a solvent-resistant bacterium, <it>Pseudomonas putida </it>GM730, and its applications in whole-cell biocatalysis

<p>Abstract</p> <p>Background</p> <p>Whole-cell biocatalysis in organic solvents has been widely applied to industrial bioprocesses. In two-phase water-solvent processes, substrate conversion yields and volumetric productivities can be limited by the toxicity of solvents to host cells and by the low mass transfer rates of the substrates from the solvent phase to the whole-cell biocatalysts in water.</p> <p>Results</p> <p>To solve the problem of solvent toxicity, we immobilized a thermostable lipase (TliA) from <it>Pseudomonas fluorescens </it>on the cell surface of a solvent-resistant bacterium, <it>Pseudomonas putida </it>GM730. Surface immobilization of enzymes eliminates the mass-transfer limitation imposed by the cell wall and membranes. TliA was successfully immobilized on the surface of <it>P. putida </it>cells using the ice-nucleation protein (INP) anchoring motif from <it>Pseudomonas syrinage</it>. The surface location was confirmed by flow cytometry, protease accessibility and whole-cell enzyme activity using a membrane-impermeable substrate. Three hundred and fifty units of whole-cell hydrolytic activity per gram dry cell mass were obtained when the enzyme was immobilized with a shorter INP anchoring motif (INPNC). The surface-immobilized TliA retained full enzyme activity in a two-phase water-isooctane reaction system after incubation at 37°C for 12 h, while the activity of the free form enzyme decreased to 65% of its initial value. Whole cells presenting immobilized TliA were shown to catalyze three representative lipase reactions: hydrolysis of olive oil, synthesis of triacylglycerol and chiral resolution.</p> <p>Conclusion</p> <p><it>In vivo </it>surface immobilization of enzymes on solvent-resistant bacteria was demonstrated, and appears to be useful for a variety of whole-cell bioconversions in the presence of organic solvents.</p

Bacterial Cell Surface Display of an Enzyme Library for Selective Screening of Improved Cellulase Variants

The bacterial surface display method was used to selectively screen for improved variants of carboxymethyl cellulase (CMCase). A library of mutated CMCase genes generated by DNA shuffling was fused to the ice nucleation protein (Inp) gene so that the resulting fusion proteins would be displayed on the bacterial cell surface. Some cells displaying mutant proteins grew more rapidly on carboxymethyl cellulose plates than controls, forming heterogeneous colonies. In contrast, cells displaying the nonmutated parent CMCase formed uniform tiny colonies. These variations in growth rate were assumed to result from altered availability of glucose caused by differences in the activity of variant CMCases at the cell surface. Staining assays indicate that large, rapidly growing colonies have increased CMCase activity. Increased CMCase activity was confirmed by assaying the specific activities of cell extracts after the expression of unfused forms of the variant genes in the cytoplasm. The best-evolved CMCases showed about a 5- and 2.2-fold increase in activity in the fused and free forms, respectively. Sequencing of nine evolved CMCase variant genes showed that most amino acid substitutions occurred within the catalytic domain of the enzyme. These results demonstrate that the bacterial surface display of enzyme libraries provides a direct way to correlate evolved enzyme activity with cell growth rates. This technique will provide a useful technology platform for directed evolution and high-throughput screening of industrial enzymes, including hydrolases

Homofermentative Production of d- or l-Lactate in Metabolically Engineered Escherichia coli RR1

We investigated metabolic engineering of fermentation pathways in Escherichia coli for production of optically pure d- or l-lactate. Several pta mutant strains were examined, and a pta mutant of E. coli RR1 which was deficient in the phosphotransacetylase of the Pta-AckA pathway was found to metabolize glucose to d-lactate and to produce a small amount of succinate by-product under anaerobic conditions. An additional mutation in ppc made the mutant produce d-lactate like a homofermentative lactic acid bacterium. When the pta ppc double mutant was grown to higher biomass concentrations under aerobic conditions before it shifted to the anaerobic phase of d-lactate production, more than 62.2 g of d-lactate per liter was produced in 60 h, and the volumetric productivity was 1.04 g/liter/h. To examine whether the blocked acetate flux could be reoriented to a nonindigenous l-lactate pathway, an l-lactate dehydrogenase gene from Lactobacillus casei was introduced into a pta ldhA strain which lacked phosphotransacetylase and d-lactate dehydrogenase. This recombinant strain was able to metabolize glucose to l-lactate as the major fermentation product, and up to 45 g of l-lactate per liter was produced in 67 h. These results demonstrate that the central fermentation metabolism of E. coli can be reoriented to the production of d-lactate, an indigenous fermentation product, or to the production of l-lactate, a nonindigenous fermentation product

Stability of lipase displayed on the surface of GM730/pJHC13 cells (■) and free form lipase (▲) during incubation at 37°C in a two-phase water-isooctane reaction system

<p><b>Copyright information:</b></p><p>Taken from "Display of a thermostable lipase on the surface of a solvent-resistant bacterium, GM730, and its applications in whole-cell biocatalysis"</p><p>BMC Biotechnology 2006;6():23-23.</p><p>Published online 19 Apr 2006</p><p>PMCID:PMC1459859.</p><p>Copyright © 2006 Jung et al; licensee BioMed Central Ltd.</p> Residual lipase activities were measured spectrophotometrically with pNPP as a substrate and calculated by assuming the initial activity was 100%