排序方式: 共有182条查询结果,搜索用时 15 毫秒
41.
William G. Pitt Mahsa Alizadeh Ghaleb A. Husseini Daniel S. McClellan Clara M. Buchanan Colin G. Bledsoe Richard A. Robison Rae Blanco Beverly L. Roeder Madison Melville Alex K. Hunter 《Biotechnology progress》2016,32(4):823-839
The high morbidity and mortality rate of bloodstream infections involving antibiotic‐resistant bacteria necessitate a rapid identification of the infectious organism and its resistance profile. Traditional methods based on culturing the blood typically require at least 24 h, and genetic amplification by PCR in the presence of blood components has been problematic. The rapid separation of bacteria from blood would facilitate their genetic identification by PCR or other methods so that the proper antibiotic regimen can quickly be selected for the septic patient. Microfluidic systems that separate bacteria from whole blood have been developed, but these are designed to process only microliter quantities of whole blood or only highly diluted blood. However, symptoms of clinical blood infections can be manifest with bacterial burdens perhaps as low as 10 CFU/mL, and thus milliliter quantities of blood must be processed to collect enough bacteria for reliable genetic analysis. This review considers the advantages and shortcomings of various methods to separate bacteria from blood, with emphasis on techniques that can be done in less than 10 min on milliliter‐quantities of whole blood. These techniques include filtration, screening, centrifugation, sedimentation, hydrodynamic focusing, chemical capture on surfaces or beads, field‐flow fractionation, and dielectrophoresis. Techniques with the most promise include screening, sedimentation, and magnetic bead capture, as they allow large quantities of blood to be processed quickly. Some microfluidic techniques can be scaled up. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:823–839, 2016 相似文献
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A novel spray bioreactor for the proliferation of plant callus; Hyoscyamus niger and Arnebia pulchra
Goojgi Sara Tahmasebi Tavakoli Mahsa Haghbeen Kamahldin Mousavi Amir Piri Khosro 《Biotechnology letters》2022,44(2):333-340
Biotechnology Letters - Unlike plant cell suspension culture, the proliferation of callus in bioreactors has received inadequate attention. The magnificent potential of plant callus becomes more... 相似文献
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Barkhordarian A Ramchandani MH Dousti M Kelly-Gleason L Chiappelli F 《Bioinformation》2012,8(7):293-295
As a direct benefit of the Health Care Reform Act (2010), concerted effort has been deployed to define and characterize the process by which the best available evidence for diagnosis or treatment intervention prognosis can be obtained. The science of research synthesis in health care has established the systematic research protocol by which randomized clinical trials and other clinical studies must be reviewed and compared for the level and quality of the evidence presented, as well as the consensus of the best available evidence synthesized and shared. This process of systematic review yields a reliable and valid approach in comparing different interventions and strategies to prevent, diagnose, treat and monitor health conditions in terms of efficacy, and or of effectiveness. The resulting bioinformation outcome of comparative effectiveness and efficacy research review of the available clinical data is expressed as a consensus of the best available evidence, which finds its way in evidence-based clinical practice guidelines, standards of care and eventually, in policies: hence, the acronym CEERAP (comparative effectiveness and efficacy review and policy). The methodological and the procedural criteria that determine and regulate the public reporting dissemination of this sort of bioinformation, and the extent of benefit to the patient's health literacy, which have remained a bit more elusive to this date, are investigated and discussed in this paper. 相似文献
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David van der Poorten Mahsa Shahidi Enoch Tay Jayshree Sesha Kayla Tran Duncan McLeod Jane S. Milliken Vikki Ho Lionel W. Hebbard Mark W. Douglas Jacob George 《PloS one》2010,5(9)
Background
Activation of hepatic CB1 receptors (CB1) is associated with steatosis and fibrosis in experimental forms of liver disease. However, CB1 expression has not been assessed in patients with chronic hepatitis C (CHC), a disease associated with insulin resistance, steatosis and metabolic disturbance. We aimed to determine the importance and explore the associations of CB1 expression in CHC.Methods
CB1 receptor mRNA was measured by real time quantitative PCR on extracted liver tissue from 88 patients with CHC (genotypes 1 and 3), 12 controls and 10 patients with chronic hepatitis B (CHB). The Huh7/JFH1 Hepatitis C virus (HCV) cell culture model was used to validate results.Principal Findings
CB1 was expressed in all patients with CHC and levels were 6-fold higher than in controls (P<0.001). CB1 expression increased with fibrosis stage, with cirrhotics having up to a 2 fold up-regulation compared to those with low fibrosis stage (p<0.05). Even in mild CHC with no steatosis (F0-1), CB1 levels remained substantially greater than in controls (p<0.001) and in those with mild CHB (F0-1; p<0.001). Huh7 cells infected with JFH-1 HCV showed an 8-fold upregulation of CB1, and CB1 expression directly correlated with the percentage of cells infected over time, suggesting that CB1 is an HCV inducible gene. While HCV structural proteins appear essential for CB1 induction, there was no core genotype specific difference in CB1 expression. CB1 significantly increased with steatosis grade, primarily driven by patients with genotype 3 CHC. In genotype 3 patients, CB1 correlated with SREBP-1c and its downstream target FASN (SREBP-1c; R = 0.37, FASN; R = 0.39, p<0.05 for both).Conclusions/Significance
CB1 is up-regulated in CHC and is associated with increased steatosis in genotype 3. It is induced by the hepatitis C virus. 相似文献46.
When grown at acidic pH, Escherichia coli cells secrete cadaverine, a polyamine known to inhibit porin-mediated outer membrane permeability. In order to understand the physiological significance of cadaverine excretion and the inhibition of porins, we isolated an OmpC mutant that showed resistance to spermine during growth and polyamine-resistant porin-mediated fluxes. Here, we show that the addition of exogenous cadaverine allows wild-type cells to survive a 30-min exposure to pH 3.6 better than cells expressing the cadaverine-insensitive OmpC porin. Competition experiments between strains expressing either wild-type or mutant OmpC showed that the lack of sensitivity of the porin to cadaverine confers a survival disadvantage to the mutant cells at reduced pH. On the basis of these results, we propose that the inhibition of porins by excreted cadaverine represents a novel mechanism that provides bacterial cells with the ability to survive acid stress. 相似文献
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Scott A. Read Enoch S. Tay Mahsa Shahidi Kate S. O’Connor David R. Booth Jacob George Mark W. Douglas 《PloS one》2015,10(8)
Treatment of chronic hepatitis C virus (HCV) infection is evolving rapidly with the development of novel direct acting antivirals (DAAs), however viral clearance remains intimately linked to the hepatic innate immune system. Patients demonstrating a high baseline activation of interferon stimulated genes (ISGs), termed interferon refractoriness, are less likely to mount a strong antiviral response and achieve viral clearance when placed on treatment. As a result, suppressor of cytokine signalling (SOCS) 3 and other regulators of the IFN response have been identified as key candidates for the IFN refractory phenotype due to their regulatory role on the IFN response. AXL is a receptor tyrosine kinase that has been identified as a key regulator of interferon (IFN) signalling in myeloid cells of the immune system, but has not been examined in the context of chronic HCV infection. Here, we show that AXL is up-regulated following HCV infection, both in vitro and in vivo and is likely induced by type I/III IFNs and inflammatory signalling pathways. AXL inhibited type IFNα mediated ISG expression resulting in a decrease in its antiviral efficacy against HCV in vitro. Furthermore, patients possessing the favourable IFNL3 rs12979860 genotype associated with treatment response, showed lower AXL expression in the liver and a stronger induction of AXL in the blood, following their first dose of IFN. Together, these data suggest that elevated AXL expression in the liver may mediate an IFN-refractory phenotype characteristic of patients possessing the unfavourable rs12979860 genotype, which is associated with lower rates of viral clearance. 相似文献
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The binding geometry of fluorouracil/cucurbit[n]urils (CB[n]s) complexes with n?=?5–8 is investigated using the first-principles van der Waals density functional (vdW-DF) method, involving full geometry optimization. Such host-guest complexes are typically calculated using conventional DFT method, which significantly underestimates non-local dispersion forces (or vdW contributions) and therefore affects interactions between respected entities. We address here the role of vdW forces for the fluorouracil and CB[n]s molecules which can form directional hydrogen bonds with each other. It was found that the inclusion of dispersion interactions significantly affects the host-guest binding properties and the hydrogen bonding between the molecules provides the main binding mechanism, while results in the same geometries for the considered complexes. The 0.84 eV binding energy, for the thermodynamically favorable state, reveals that the interaction of fluorouracil with CB[n]s is an exothermic interaction and typical for strong hydrogen bonding. Furthermore, we have investigated the binding nature of these host-guest systems in aqueous solution with ab initio MD simulations adopting vdW-DF method. These findings afford evidence for the applicability of the vdW-DF approach and provide a realistic benchmark for the investigation of the host-guest complexes. Figure
The binding geometry of fluorouracil/CB[n]s complexes is investigated using the first-principles vdW-DF method, involving full geometry optimization. 相似文献
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Mahsa Moshfegh Ahmad Reza Shahverdi Gholamreza Zarrini Mohammad Ali Faramarzi 《Extremophiles : life under extreme conditions》2013,17(4):677-687
An extracellular haloalkaliphilic thermostable α-amylase producing archaeon was isolated from the saltwater Lake Urmia and identified as Halorubrum xinjiangense on the basis of morphological, biochemical, and molecular properties. The enzyme was purified to an electrophoretically homogenous state by 80 % cold ethanol precipitation, followed by affinity chromatography. The concentrated pure amylase was eluted as a single peak on fast protein liquid chromatography. The molecular mass of the purified enzyme was about 60 kDa, with a pI value of 4.5. Maximum amylase activity was at 4 M NaCl or 4.5 M KCl, 70 °C, and pH 8.5. The K m and V max of the enzyme were determined as 3.8 mg ml?1 and 12.4 U mg?1, respectively. The pure amylase was stable in the presence of SDS, detergents, and organic solvents. In addition, the enzyme (20 U) hydrolyzed 69 % of the wheat starch after a 2-h incubation at 70 °C in an aqueous/hexadecane two-phase system. 相似文献