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91.
Burkholderia cenocepacia is an important respiratory pathogen in persons with cystic fibrosis. We compared the proteomes of clinical and environmental isolates of B. cenocepacia by using a 2D liquid separation method coupled with mass spectrometry. Proteome maps of four B. cenocepacia isolates were generated. In the first dimension, 5 mg of protein from each isolate was fractionated by chromatofocusing (CF) in the range of pH 4.0-7.0. In the second dimension, each CF fraction was separated by NPS-RP-HPLC. Results of the 2D liquid separation were visualized as 2D UV maps, which allowed direct comparison of proteomes with high resolution and reproducibility. From the proteomic comparison of the four isolates, 38 of 96 differentially abundant proteins were identified by peptide mass fingerprinting and MS/MS sequence analysis using a partially annotated B. cenocepacia protein database. Many of the identified proteins in the clinical isolates are involved in gene translation and bacterial virulence such as transmissibility, resistance, and quorum sensing. 相似文献
92.
Hydrodynamic cavitation is a powerful tool for the enhancement of various processing applications. This study utilizes continuous hydrodynamic cavitation (CHC) for the inactivation of pathogens in milk for the first time. The thermal characteristics, inactivation performance, damage on the nutritional composition, product safety, and cost of the advanced rotational hydrodynamic cavitation reactor at pilot scale were comprehensively investigated. The inactivation results demonstrated that 5.89, 5.53, and 2.99 ± 0.08 log reductions of Escherichia coli, Staphylococcus aureus, and Bacillus cereus were achieved, respectively, at a final treatment temperature of 70 °C for 1–2 s. Moreover, the detrimental effect of CHC on the nutritional composition of milk, including mineral, fat, protein, and vitamin contents, was similar to that of high-temperature short-time method. The change in the concentrations of general bacteria and E. coli, as well as the pH value and acidity of the CHC treated milk stored at 5 °C for 14 days was found to be close to that of low-temperature long-time pasteurized milk. The cost of the present CHC treatment was $0.00268/L with a production rate of 4.2 L/min. CHC appears to be a remarkable method for the continuous processing of milk, as well as other liquid foods with high nutrition and “fresh-picked” flavor, due to its high efficacy, good scalability, high production capacity, and low operating and equipment costs. 相似文献
93.
In healthcare facilities, environmental microbes are responsible for numerous infections leading to patient’s health complications and even death. The detection of the pathogens present on contaminated surfaces is crucial, although not always possible with current microbial detection technologies requiring sample collection and transfer to the laboratory. Based on a simple sonochemical coating process, smart hospital fabrics with the capacity to detect live bacteria by a simple change of colour are presented here. Prussian Blue nanoparticles (PB-NPs) are sonochemically coated on polyester-cotton textiles in a single-step requiring 15 min. The presence of PB-NPs confers the textile with an intensive blue colour and with bacterial-sensing capacity. Live bacteria in the textile metabolize PB-NPs and reduce them to colourless Prussian White (PW), enabling in situ detection of bacterial presence in less than 6 h with the bare eye (complete colour change requires 40 h). The smart textile is sensitive to both Gram-positive and Gram-negative bacteria, responsible for most nosocomial infections. The redox reaction is completely reversible and the textile recovers its initial blue colour by re-oxidation with environmental oxygen, enabling its re-use. Due to its simplicity and versatility, the current technology can be employed in different types of materials for control and prevention of microbial infections in hospitals, industries, schools and at home. 相似文献
94.
Bacterial cellulose/lotus root starch (BC/LRS) composites were prepared by cultivating Acetobacter xylinum in nutrient media containing gelatinized lotus root starch. Low concentrations of gelatinized LRS had increased BC production with the maximum value at 6.67 g/L when 5 g/L of LRS was added in the culture media and the composites had thicker and denser fibrils compared with those of BC with low concentrations of LRS (2.5 and 5 g/L). When the concentration of LRS was increased above 7.5 g/L, the morphology of the BC/LRS composites contained more fibril layers that were linked with LRS. The results from X-ray diffraction (XRD) demonstrated that there was no significant difference in structure between BC and BC/LRS composites except a slight increase in crystallinity for BC/LRS composites as the concentration of LRS was lifted up. The tensile tests were performed to display BC/LRS composites prepared with LRS concentration at 2.5 and 5 g/L in media had the tensile strength of 54 and 60 MPa, respectively, which indicated an improvement in mechanical property compared to the unmodified BC (45 MPa). Live/dead assay with chondrocytes seeded on BC/LRS composite revealed higher cell viability ranging from 85% to 90% than BC. Furthermore, cell morphology with typical spindle shape was observed on the surfaces of BC/LRS composite by confocal microscope. Through the overall results, it shows that this study has provided a guidance to prepare BC/LRS composites with better cell biocompatibility and higher mechanical strength than those of BC for the potential use in cartilage tissue engineering. 相似文献
95.
d-glycero-d-manno-Heptose 1,7-bisphosphate (HBP) plays a unique role in bacteriology. We describe in this study a very efficient synthesis of HBP, featuring a highly 6-D-selective construction of the heptose scaffold as well as a double phosphorylation step installing, in a single operation and in a β-stereoselective manner, the 1- and the 7-phosphates. 相似文献
96.
97.
ZhanboWen Wenhui Yang Na Li Jie wang Lingfei Hu Jinsong Li Zhe Yin Ke Zhang Xiaokai Dong 《Particuology》2014,(2):82-87
To assess the risk of infectious bacterial aerosols leaking to the environment, the filtration efficiency of a biosafety level 3 (BSL-3) laboratory high-efficiency particulate (HEPA) filter was investigated using the aerosolized bacteria Serratia marcescens. The aerosol size was measured using an Andersen sampler. Eight first stage HEPA filters (numbered 1-87 were distributed in contaminated labs and exhausts from each of the first stage HEPA filters were aggregated and filtered through one second stage HEPA filter before being released to the environment. In total, 8 first-stage and I second-stage HEPA filters from the BSL-3 air purification system were analyzed. No S. marcescens was detected in first stage filters 1,2, 4, 5, 7 and 8 and the second stage HEPA filter. The filtration efficiencies against aerosolized S. marcescens were 〉99.9999%. First stage filter numbers 3 and 6 had filtration efficiencies of 99.9825% and 99.9906% respectively. When filter number 3 was replaced by a new filter and the bracket for filter number 6 was sealed, no aerosolized S. marcescens was detected in the filtered air. Our work suggests that the BSL-3 laboratory HEPA filter air purification system is effective against bacterial aerosols, with little to no bacterial leakage into the environment. 相似文献
98.
Gardner JY Brillhart DE Benjamin MM Dixon LG Mitchell LM Dimandja JM 《Journal of separation science》2011,34(2):176-185
The cellular fatty acid profiles of eight strains of Bacillus, Staphylococcus, and Enterobacteriacae (Escherichia coli and Salmonella) were analyzed by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry. A novel template method was developed to standardize the raw two-dimensional gas chromatography retention data through the use of a chemical indexing mixture. Analyte retention coordinates were normalized in the primary dimension with respect to a series of n-alkanes (Kovats index) and in the secondary dimension with respect to a series of aromatic hydrocarbons (Lee index). Fatty acid profiles extracted from the templates were compared by multidimensional scaling and principal component analysis. Differences in the profiles of Gram-positive and Gram-negative bacteria were observed, and a series of heterogeneous mixtures comprising different fractions (containing one Gram-positive and one Gram-negative bacteria strain) were also distinguished from their homogeneous constituents. 相似文献
99.
100.
《Analytical letters》2012,45(16):1291-1302
Abstract The selectivity of a previously reported bacterial arginine electrode has been greatly enhanced, with no loss of response to arginine. The response of this sensor to glutamine and asparagine was found to be due to a contaminant growing in the bacterial layer of the electrode. The addition of 1 × 10?3 M sodium azide to the working buffer and cold storage of the electrode effectively controlled the growth of the contaminating bacteria and maintained the low initial response of the electrode to these amino acids in the concentration range of 4 × 10?5 to 1.5 × 10?3 M. At these optimum conditions, the response of the sensor to arginine was unaffected by the presence of a mixture of amino acids at physiological levels. 相似文献