Extraction, Bacteriostatic Effect and Synergistic Mechanism of Bacteriostatic Effect of Taxifolin in Larch in Combination with Leucocyanidin

Using larch as raw material, taxifolin was extracted by ultrasonic-assisted ethanol hot leaching. Escherichia coli and Staphylococcus aureus were used as typical test bacteria respectively, and the bacterial inhibitory effects of taxifolin was analyzed by observing the morphological structure of bacteria and measuring the changes in bacterial growth, cell membrane leakage and antioxidant enzyme system activities. The final product was obtained with 90% purity and 0.35% extraction rate of taxifolin. The minimum inhibitory concentration of taxifolin was 1.2 mg/mL for both strains, and the inhibition rate was 81.12% and 83.95%, respectively. After the electron microscopy analysis, the surface of the bacteria cells was disrupted and the contents inside the cells were leaked. In E. coli, the OD260 test values of 1/2 MIC, 1 MIC and 2 MIC were 1.18, 1.52 and 1.88 times higher than those of the control group after 24 h incubation. The relative activities of extracellular β-galactosidase were 79.15% and 70.1%, respectively, and the growth rate calculated by the the Bliss independent model was 0.0142. S. aureus showed a synergistic inhibition effect. Under the conditions of drug combination, the bacterial cell membrane disruption extent was significantly enhanced by the low concentration and the inhibition effect was more significant. The β-galactosidase activity in the culture supernatant was 87.01% higher than that of 2 MIC group alone for S. aureus by 16.91%, and the 24 h CAT, SOD and POD enzyme activities were higher than that of 1 MIC group alone for S. aureus, which were 1.28, 1.25 and 1.11 times higher, respectively. The study could lay the theoretical foundation for the development and application of taxifolin as a food preservation and preservative

Characterisation of a Novel White Laccase from the Deuteromycete Fungus Myrothecium verrucaria NF-05 and Its Decolourisation of Dyes

A novel ‘white’ laccase was purified from the deuteromycete fungus, Myrothecium verrucaria NF-05, which was a high laccase-producing strain (40.2 U·ml−1 on the thirteenth day during fermentation). SDS-PAGE and native-PAGE revealed a single band with laccase activity corresponding to a molecular weight of approximately 66 kDa. The enzyme had three copper and one iron atoms per protein molecule determined by ICP-AES. Furthermore, both UV/visible and EPR spectroscopy remained silence, indicating the enzyme a novel laccase with new metal compositions of active centre and spectral properties. The N-terminal amino acid sequence of the purified protein was APQISPQYPM. Together with MALDI-TOF analysis, the protein revealed a high homology of the protein with that from reported M. verrucaria. The highest activity was detected at pH 4.0 and at 30°C. The enzyme activity was significantly enhanced by Na+, Mn2+, Cu2+ and Zn2+ while inhibited by DTT, NaN3 and halogen anions. The kinetic constant (Km) showed the enzyme was more affinitive to ABTS than other tested aromatic substrates. Twelve structurally different dyes could be effectively decolourised by the laccase within 10 min. The high production of the strain and novel properties of the laccase suggested its potential for biotechnological applications

Corneal Surface Ablation Laser Refractive Surgery for the Correction of Myopia: A Network Meta-analysis

PURPOSE: To systematically compare the efficacy, predictability, safety, postoperative haze, pain scores, and epithelial healing time of four corneal surface ablation procedures. METHODS: PubMed, Embase, Cochrane Library, and the U.S. trial registry were searched up to June 2018. Randomized controlled trials were selected. Efficacy (uncorrected distance visual acuity of 20/20 or better), predictability (refractive spherical equivalent within ±0.50 diopters [D] of the target), and safety (loss of two or more lines of spectacle corrected distance visual acuity) were set as primary outcome measures. Haze, pain scores, and epithelial healing time were set as secondary outcome measures. RESULTS: Eighteen studies involving 1,423 eyes were included. According to the Grading of Recommendations Assessment, Development, and Evaluation, the quality of outcomes were moderate to high (70.6%). There were no differences in efficacy, predictability, safety, haze, day 1 pain, and epithelial healing time between treatments. Epithelial laser in situ keratomileusis (epi-LASIK) had statistically significantly higher pain scores on day 3 compared to photorefractive keratectomy (PRK) (weighted mean differences [WMD] = 2.2, 95% credible intervals [CrI] = 0.19 to 4.01) and transepithelial PRK (T-PRK) (WMD = 2.7, 95% CrI = 0.51 to 4.84). The surface under the cumulative ranking curve ranking results (best to worst) showed laser epithelial keratomileusis (LASEK) ranked highest for efficacy, predictability, safety, and day 1 pain scores. Epi-LASIK ranked best for grade 1 haze scores. T-PRK ranked best for haze of 0.5 or higher, haze scores day 3 pain scores, and epithelial healing time. CONCLUSIONS: Surface laser refractive surgeries are comparable in terms of efficacy, predictability, safety, and postoperative haze except for day 3 pain scores, with epi-LASIK being more painful compared to PRK and T-PRK. [J Refract Surg. 2018;34(11):726-735.]

The Comparative Study on the Rapid Decolorization of Azo, Anthraquinone and Triphenylmethane Dyes by Anaerobic Sludge

An anaerobic sludge (AS), capable of decolorizing a variety of synthetic dyes, was acclimated and is reported here. The sludge presented a much better dye decolorizing ability than that of different individual strains. A broad spectrum of dyes could be decolorized by the sludge. Continuous decolorization tests showed that the sludge exhibited the ability to decolorize repeated additions of dye. The chemical oxygen demand (COD) removal rate of the dye wastewater reached 52% after 12 h of incubation. Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) profiles revealed that the microbial community changed as a result of varying initial concentrations of dyes. Phylogenetic analysis indicated that microbial populations in the sludge belonged to the phyla Acidobacteria, Firmicutes, Bacteroidetes, Chloroflexi and Proteobacteria. The degradation products of the three types of dye were identified. For azo dyes, the anaerobic sludge converted Methyl Orange to N,N-dimethylbenzene-1,4-diamine and 4-aminobenzenesulfonic acid; for triphenylmethane dyes, after Malachite Green was decolorized, the analyzed products were found to be a mixture of N,N-dimethylbenzenamine, 3-dimethyl-aminophenol and 4-dimethylaminobenzophenone; for anthraquinone dyes, two products (acetophenone and 2-methylbenzoic acid) were observed after Reactive Blue 19 decolorization. Together, these results suggest that the anaerobic sludge has promising potential for use in the treatment of industrial wastewater containing various types of dyes

De Novo Iron Oxide Hydroxide, Ferrihydrite Produced by Comamonas testosteroni Exhibiting Intrinsic Peroxidase-Like Activity and Their Analytical Applications

Natural enzyme mimics have attracted considerable attention due to leakage of enzymes and their easy denaturation during their storage and immobilization procedure. Here in this study, for the first time, a new iron oxide hydroxide, ferrihydrite – Fe1.44O0.32 (OH) 3.68 magnetic nanoparticles were synthesized by bacterial strain named Comamonas testosteroni. The characterization of the produced magnetic nanoparticles was confirmed by transmission electron microscopy (TEM), Fourier-transform spectroscopy (FTIR), X-ray diffraction (XRD), and magnetization hysteresis loops. Further, these extracted nanoparticles were proven to have biogenic magnetic behavior and to exhibit enhanced peroxidase-like activity. It is capable of catalyzing the oxidation of 3, 3′, 5, 5′-Tetramethylbenzidine (TMB) by H2O2 to produce blue color (typical color reactions). Catalysis was examined to follow Michaelis-Menton kinetics and the good affinity to both H2O2 and TMB. The Km value of the Fe1.44O0.32 (OH) 3.68 with H2O2 and TMB as the substrate was 0.0775 and 0.0155 mM, respectively, which were lower than that of the natural enzyme (HRP). Experiments of electron spin resonance (ESR) spectroscopy proved that the BMNPs could catalyze H2O2 to produce hydroxyl radicals. As a new peroxidase mimetic, the BMNPs were exhibited to offer a simple, sensitive, and selective colorimetric method for determination of H2O2 and glucose and efficiently catalyze the detection of glucose in real blood samples

In Vitro Antifungal Activity of Dihydrochelerythrine and Proteomic Analysis in Ustilaginoidea virens

Dihydrochelerythrine (DHCHE) is an isoquinoline compound, which has distinct antifungal activity and can induce apoptosis. The antifungal activity of DHCHE against five rice pathogenic fungi was studied in vitro. At the concentration of 7.5 mg/L, DHCHE exhibited the highest efficacy among tested compounds in inhibiting mycelium growth, with an inhibition rate of 68.8% in Ustilaginoidea virens, which was approximately 2.4 times of that of validamycin (28.7%). After exposure to DHCHE, transmission electron micrographs revealed spores showed incomplete organelles, malformed cell walls and nuclear membranes, as well as irregular lipid spheres. Reactive oxygen species accumulation in treated spores was markedly higher than that in control spores. DHCHE induced cell damage increased in a dose-dependent manner, as indicated by the decrease in mitochondrial membrane potential and initiation of apoptosis. The differences of expression levels of Fip1, ACP1, PMS2 and COX13 that are important for oxidative phosphorylation and mismatch repair pathway were significant, which may be some of the reasons for the induction of apoptosis in DHCHE-treated U. virens. The protein levels of Fip1, ACP1, PMS2 and COX13 agreed with protein fold change ratio from parallel reaction monitoring Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathway of differentially expressed proteins were further analyzed. These findings will help to elucidate the mechanisms associated with antifungal and pro-apoptotic effects of DHCHE on U. virens, thereby aiding the potential development of novel pesticides

The Comparative Study on the Rapid Decolorization of Azo, Anthraquinone and Triphenylmethane Dyes by Anaerobic Sludge

An anaerobic sludge (AS), capable of decolorizing a variety of synthetic dyes, was acclimated and is reported here. The sludge presented a much better dye decolorizing ability than that of different individual strains. A broad spectrum of dyes could be decolorized by the sludge. Continuous decolorization tests showed that the sludge exhibited the ability to decolorize repeated additions of dye. The chemical oxygen demand (COD) removal rate of the dye wastewater reached 52% after 12 h of incubation. Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) profiles revealed that the microbial community changed as a result of varying initial concentrations of dyes. Phylogenetic analysis indicated that microbial populations in the sludge belonged to the phyla Acidobacteria, Firmicutes, Bacteroidetes, Chloroflexi and Proteobacteria. The degradation products of the three types of dye were identified. For azo dyes, the anaerobic sludge converted Methyl Orange to N,N-dimethylbenzene-1,4-diamine and 4-aminobenzenesulfonic acid; for triphenylmethane dyes, after Malachite Green was decolorized, the analyzed products were found to be a mixture of N,N-dimethylbenzenamine, 3-dimethyl-aminophenol and 4-dimethylaminobenzophenone; for anthraquinone dyes, two products (acetophenone and 2-methylbenzoic acid) were observed after Reactive Blue 19 decolorization. Together, these results suggest that the anaerobic sludge has promising potential for use in the treatment of industrial wastewater containing various types of dyes

SDS–PAGE (a) and native PAGE (b) of purified laccase from <i>M.verrucaria</i> NF-05.

<p>(a) Lane 1: denatured protein marker, Lane 2: purified laccase; (b) Lane 1: purified laccase with Coomassie Brilliant Blue R-250staining, Lane 2: purified laccase with ABTS staining.</p