Controlled Release of Curcumin by Graphene Oxide/Chitosan/Sodium Alginate Hydrogel Multilayer Nanocomposites and Evaluate its Synergistic Antibacterial Activity

Curcumin has many medical properties, such as anti-inflammatory, anti-microbial, antioxidant, and anti-tumor activities. However, its hydrophobic nature results in less solubility and fast metabolism. Nowadays, designing a cargo based on nano-biotechnology is an efficient method to overcome these limitations of curcumin. This study synthesized graphene oxide/chitosan/sodium alginate (GCA) multilayer nanocomposites according to a layer-by-layer (LBL) assembly to load curcumin. Firstly, for graphene oxide/chitosan (GC) nanocomposite synthesis, graphene oxide (G) suspension was added to the chitosan (CS) solution dropwise during stirring. Then, sodium alginate (A) in water was added to the GC suspension drop wisely, centrifuged, and lyophilized. This GCA multilayer nanocomposite showed a layered structure with negative zeta potential. Though the drug loading efficiency of this GCA multilayer was not as high as graphene oxide, its curcumin release was pH-dependent. The highest drug release belonged to GCA due to the presence of curcumin in the hydrogel network without tight binding. This release was pH-dependent as the curcumin release after 24 h was 80% in pH 5 for GCA, while this amount was 60 % in pH 7 because of hydrogel network disruption in the acidic environment. The antibacterial results exhibited that this GCA multilayer did not show any antibacterial activity. It was significant that curcumin did not affect E. coli, though the minimum inhibitory concentration (MIC) for S. aureus was 300 µg/ml. Ciprofloxacin has been used to investigate the effect of GCA nanocomposite’s synergetic release of curcumin and antibiotics. Results showed that ciprofloxacin increased the inhibition zone diameter for S. aureus, but this was not observed in E. coli. Overall, it can be concluded that the antibacterial activity of curcumin is not evitable. To explain this, the antioxidant activity of curcumin, which reduces the radicals due to ciprofloxacin activity, can be considered

A specific, rapid and high-throughput cascade catalytic method for determination of plasma uric acid by using uricase and trivalent peroxidase-mimicking DNAzyme

In this study, we report a facile and cost-effective system for selective measurement of uric acid (UA) using a cascade mechanism composed of Uricase and peroxidase-mimicking trivalent DNAzyme. A three G-quadruplex-hemin complex was engaged as the peroxidase-mimicking DNAzyme. In this cascade catalysis system, UA was oxidized by uricase to produce hydrogen peroxide, which was also acted as a substrate for the oxidation of 3, 3�, 5, 5� tetramethylbenzidine (TMB) by a peroxidase-mimicking trivalent DNAzyme. TMB oxidation showed a straight relationship with UA concentration. The cascade catalysis system displayed high selectivity toward UA because of the natural selectivity of uricase. This cascade uric acid sensing system revealed the best activity at 30 °C and pH 7.0, which indicated its capacity to uric acid sensing near physiological conditions. The linear regression equation for UA was quantified as A = 0.0072C + 0.0197, with a correlation coefficient of 0.9906. Results suggested that this system could identify as low as 0.66 μM of uric acid with a linear range from 2.5 to 40 μM. Results exhibited that the interfering public components had no noticeable absorbance values. Overall, these results indicated that this facile system would be valuable for uric acid measurement in the medical laboratory. © 2020 Elsevier Lt

Learning and Memory Impairment Induced by the Injection of Ascorbic Acid and Ascorbate Oxidase into the Hippocampus in the Morris Water Maze

BACKGROUND AND OBJECTIVE: Ascorbic acid has a wide range of functions in the central nervous system such as neuromodulator and antioxidant. Ascorbic acid intervenes with the neurotransmitters involved in learning and memory. In this study, we examined the effects of its injection and its removal enzyme in the hippocampal CA1 region on spatial learning and retention. METHODS: We used 49 Wistar rats in this study (220-270 mg/kg) and we divided them into seven groups including: control, sham (recipients of solvent), ascorbate oxidase (0.2, 0.4 &micro;g/kg), ascorbic acid (24, 12&micro;g/kg), and inactive ascorbate oxidase (0.2 &micro;g/kg). Bilateral cannula was performed in the hippocampal CA1 region using stereotaxy device. After one week of recovery, one microliter of the drugs was injected by a Hamilton syringe. Spatial learning and retention was measured by using the Morris water maze. FINDINGS:&nbsp;The results show that 12 &micro;g/kg dose of ascorbic acid increases mileage (1012.98&plusmn;63.55) and escape latency (55.48&plusmn;2.38) compared to the control group (633.33&plusmn;18.46) (45.9&plusmn;1.84) (p<0.05). Also mileage (1123.73&plusmn;108.89) and escape latency delay (57.31&plusmn;1.18) were raised with 24 &micro;g/kg dose of ascorbic acid compared to the control group (p<0.01). It was determined that ascorbate oxidase with both 0.2&micro;g/kg (p<0.01) and 0.4&micro;g/kg (p<0.001) dose increased the mileage and escape latency compared to the control group. CONCLUSION: The results showed that the injection of ascorbic acid and its removal enzyme in the hippocampal CA1 region leads to spatial learning and retention loss

Production and characterization of an acido-thermophilic, organic solvent stable cellulase from Bacillus sonorensis HSC7 by conversion of lignocellulosic wastes

The acidophilic and thermophilic cellulase would facilitate the conversion of lignocellulosic biomass to biofuel. In this study, Bacillus sonorensis HSC7 isolated as the best thermophilic cellulose degrading bacterium from Gorooh hot spring. 16S rRNA gene sequencing showed that, this strain closely related to the B. sonorensis. CMCase production was considered under varying environmental parameters. Results showed that, sucrose and (NH4)2SO4 were obtained as the best carbon and nitrogen sources for CMCase production. B. sonorensis HSC7 produced CMCase during the growth in optimized medium supplemented with agricultural wastes as sole carbon sources. The enzyme was active with optimum temperature of 70 °C and the optimum CMCase activity and stability observed at pH 4.0 and 5.0, respectively. These are characteristics indicating that, this enzyme could be an acidophilic and thermophilic CMCase. Furthermore, the CMCase activity improved by methanol (166%), chloroform (152%), while it was inhibited by DMF (61%). The CMCase activity was enhanced in the presence of Mg+2 (110%), Cu+2 (116%), Triton X-100 (118%) and it retained 57% of its activity at 30% NaCl. The compatibility of HSC7 CMCase varied for each laundry detergent, with higher stability being observed in the presence of Taj® and darya®. This enzyme, that is able to work under extreme conditions, has potential applications in various industries

Isolation, identification and characterization of organic solvent tolerant protease from Bacillus sp. DAF-01

Introduction: Organic solvent-tolerant bacteria are relatively novel extermophilic microorganisms, which can produce organic tolerant protease with capacity of being used in industrial biotechnology for producing high-value compounds. Therefore, finding of these bacteria has drawn much researchers attention nowadays. Materials and Methods: In this project, samples were collected from a hot spring, located in Jiroft. Samples were incubated in medium supplemented with cyclohexane and toluene for 3 days. Screening of protease producing bacteria was performed on the specific media, SKM (Skim milk agar), based on clear area diameter. The best bacterium was identified based on 16s rDNA gene. Protease activity was considered in different temperatures, pH and organic solvents.Results: Sequence alignment and phylogenetic tree results showed that this bacteria was closely related to Bacillus niacini, with 97% homology. Enzymatic studies showed that, this enzyme was active at a wide range of temperatures, 20-90 °C and it,s optimal activity was in 60 °C. In addition, maximum protease activity was obtained in the 8-9 range of pH, and optimal stability was also at pH 9.0. Protease activity in the presence of methanol, toluene, isopropanol, cyclohexane and DMF ‏showed that, remaining activity was at least 80% compared to the control (without organic solvent) Discussion and Conclusion: Thermopilic capacity, being active in alkaline protease and high protease stability in the presence of organic solvents all herald a remarkable application for using in different industries