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391.
    
In recent years, thermophoresis has emerged as a promising tool for quantifying biomolecular interactions. The underlying microscopic physical effect is still not understood, but often attributed to changes in the hydration layer once the binding occurs. To gain deeper insight, we investigate whether non-equilibrium coefficients can be related to equilibrium properties. Therefore, we compare thermophoretic data measured by thermal diffusion forced Rayleigh scattering (TDFRS) (which is a non-equilibrium process) with thermodynamic data obtained by isothermal titration calorimetry (ITC) (which is an equilibrium process). As a reference system, we studied the chelation reaction between ethylenediaminetetraacetic acid (EDTA) and calcium chloride (CaCl2) to relate the thermophoretic behavior quantified by the Soret coefficient ST to the Gibb’s free energy ΔG determined in the ITC experiment using an expression proposed by Eastman. Finally, we have studied the binding of the protein Bovine Carbonic Anhydrase I (BCA I) to two different benzenesulfonamide derivatives: 4-fluorobenzenesulfonamide (4FBS) and pentafluorobenzenesulfonamide (PFBS). For all three systems, we find that the Gibb’s free energies calculated from ST agree with ΔG from the ITC experiment. In addition, we also investigate the influence of fluorescent labeling, which allows measurements in a thermophoretic microfluidic cell. Re-examination of the fluorescently labeled system using ITC showed a strong influence of the dye on the binding behavior.  相似文献   
392.
    
Natural aldolase enzymes and created retro-aldolase protein catalysts often catalyze both aldol and retro-aldol reactions depending on the concentrations of the reactants and the products. Here, we report that the directionality of protein catalysts can be altered by replacing one amino acid. The protein catalyst derived from a scaffold of a previously reported retro-aldolase catalyst, catalyzed aldol reactions more efficiently than the previously reported retro-aldolase catalyst. The retro-aldolase catalyst efficiently catalyzed the retro-aldol reaction but was less efficient in catalyzing the aldol reaction. The results indicate that protein catalysts with varying levels of directionality in usually reversibly catalyzed aldol and retro-aldol reactions can be generated from the same protein scaffold.  相似文献   
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Salmonella continues to be a major food safety and public health threat. In the present study, Salmonella enterica subsp. enterica serotypes Enteritidis (SE) and Typhimurium (ST) were isolated from poultry and characterized for virulence, antimicrobial susceptibility, and biofilm formation. Prevalence of Salmonella serotypes in poultry was 3.35%; predominant serotypes isolated were S. Enteritidis (68.1%) and S. Typhimurium (31.8%). Source-wise, Salmonella were isolated from retail market chicken meat (4.8%), live chicken at farm (2.5%), and table eggs (2.1%). Salmonella isolates produced invA gene of 284 bp (100%), spvR gene of 310 bp (77.27%), spvC gene of 571 bp (22.72%), and stn gene of 260 bp (100%) as virulence/ pathogenicity determinants. Salmonella isolates exhibited resistance to common antimicrobials; 72.7% isolates showed multiple resistance (≥3 antimicrobial class), highest resistance was observed for polymyxin-B (81.8%) followed by nalidixic acid (72.7%), colistin (59.1%), ampicillin/tetracyline (45.5%), ampicillin + sulbactam (40.9%), cefodroxil (18.2%), streptomycin (9.1%), and cefazidine/ceftriaxone-tazobactam (4.5%). Multiple antimicrobial resistance (MAR) index of poultry Salmonella isolates ranged from 0.11 to 0.35; wherein, 59.1% isolates showed MAR of >0.2. About 81.8% Salmonella isolates produced biofilm and were categorized as strong (13.6%), moderate (45.4%), and weak (22.7%) biofilm producers. Occurrence of antimicrobial resistant virulent Salmonella strains in poultry requires implementation of suitable strategies so as to protect the public health.  相似文献   
395.
    
The study explored biological synthesis of metallic silver nanoparticles (AgNPs) from the less explored non‐pathogenic coprophilous fungus, sterile mycelium, PM0651419 and evaluates the antimicrobial efficacy of biosynthesised AgNPs when impregnated in wound fabrics and in combination with six antimicrobial agents. AgNPs alone proved to be potent antibacterial agents and in combination they enhanced the antibacterial activity and spectrum of antibacterials used in the study against a microbiologically diverse battery of Gram positive, Gram negative and multidrug‐resistant bacteria. AgNPs impregnated on the wound dressings established their antibacterial activity by significantly reducing the bacterial load of pathogenic bacteria like Staphylococcus aureus and Bacillus subtilis e stablishing potential as effective antimicrobial wound dressings for treatment of polymicrobial wound infections. This study presents the first report on the potential of biosynthesis of AgNPs from the under explored class of coprophilous fungi. Their promise to be used in wound dressings and as potent antibacterials alone and in combination is evaluatedInspec keywords: silver, nanoparticles, nanofabrication, nanomedicine, biomedical materials, microorganisms, antibacterial activity, wounds, fabricsOther keywords: antibacterial activity, coprophilous fungus PM0651419, biological synthesis, metallic silver nanoparticles, nonpathogenic coprophilous fungus, sterile mycelium, antimicrobial efficacy, biosynthesised AgNPs, wound fabrics, microbiologically diverse battery, Gram positive bacteria, Gram negative bacteria, multidrug‐resistant bacteria, wound dressings, bacterial load, pathogenic bacteria, Staphylococcus aureus, Bacillus subtilis, polymicrobial wound infections, Ag  相似文献   
396.
The males of the decorator wasps Eucerceris have been observed to display abdomen-dragging behavior on plants surrounding their nest. It is thought that this applies a territorial-marking sex pheromone that serve to alert females to the males' territory for courtship and mating. The extracts of three species E. rubripes, E. conata, and E. tricolor have been analyzed by GC-MS. The gas chromatograms revealed the presence, in large quantities, of one common volatile compound in the male head extracts. By analogy with the closely related bee wolves Philanthus, we believe the pheromone is produced in the mandibular glands. Utilizing mass spectrometry, microreactions, FT-IR, and 1H and 13C NMR spectroscopy the structure of the pheromone was proposed to be (Z)-3-hexenyl 3-hydroxybutanoate, which was confirmed by synthesis. The absolute configuration of the chiral center was determined to be R for the three species by preparing the Mosher esters of the insect samples and comparing their GC retention times with a synthetic sample of known absolute configuration. In addition 2- and 3-hexenoic acid and some aromatic compounds were also found in varying quantities in both males and females along with hydrocarbons and fatty acids, although no species-specific profiles emerged.  相似文献   
397.
    
Mitochondria are dynamic organelles that undergo rounds of fission and fusion and exhibit a wide range of morphologies that contribute to the regulation of different signaling pathways and various cellular functions. It is important to understand the differences between mitochondrial structure in health and disease so that therapies can be developed to maintain the homeostatic balance of mitochondrial dynamics. Mitochondrial disorders are multisystemic and characterized by complex and variable clinical pathologies. The dynamics of mitochondria in mitochondrial disorders is thus worthy of investigation. Therefore, in this study, we performed a comprehensive analysis of mitochondrial dynamics in ten patient-derived fibroblasts containing different mutations and deletions associated with various mitochondrial disorders. Our results suggest that the most predominant morphological signature for mitochondria in the diseased state is fragmentation, with eight out of the ten cell lines exhibiting characteristics consistent with fragmented mitochondria. To our knowledge, this is the first comprehensive study that quantifies mitochondrial dynamics in cell lines with a wide array of developmental and mitochondrial disorders. A more thorough analysis of the correlations between mitochondrial dynamics, mitochondrial genome perturbations, and bioenergetic dysfunction will aid in identifying unique morphological signatures of various mitochondrial disorders in the future.  相似文献   
398.
Incubation of carcinogens with post-mitochondrial supernatant (PMS) and NADPH releases ribosomes from microsomes resulting in increased RNA concentration in post-microsomal supernatant. However, non-carcinogens fail to do so. Enhanced concentration of RNA in test over control samples can provide a useful index for the carcinogenicity of environmental pollutants.  相似文献   
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400.
The effectiveness of ambroxol in the prevention of neonatal respiratory distress syndrome and in reducing the need for intermittent mandatory ventilation and oxygen therapy was studied in 88 mothers whose infants was born between 24 and 34 weeks of gestation and who were randomized either for treatment with ambroxol (group A = 42) or served as control (group B = 46). There were no significant differences in the mean gestational age, birth weight or Apgar score between the two groups. We found no significant differences in occurrence of respiratory distress syndrome (55% vs 45%), in support by intermittent mandatory ventilation (71% vs 72%) or oxygen therapy (74% vs 75%) at 12 h of age between groups A and B. CONCLUSION: This study does not suggest the efficacy of antenatal ambroxol treatment both for the prevention of neonatal respiratory distress syndrome and for the reduction of its severity.  相似文献   
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