A facile and promising approach was developed to fabricate enzyme-based 3D-ordered macroporous biocatalysts (enzyme-based inverse opals) by using the colloidal crystal templating method. Horseradish peroxidase- and amylase-based inverse opals were prepared, which verified that this method is suitable for various enzymes.
Aim
Abnormally high levels of homocysteine (Hcy) are associated with autism spectrum disorder. Betaine is a methyl group donor in Hcy metabolism, and is known to prevent noxious Hcy accumulation. This study explored whether betaine could influence Hcy metabolism in a mouse model of autism and ameliorate behavioral abnormalities.
Methods
Pregnant ICR mice were administered valproic acid (VPA) intraperitoneally on Embryonic Day 12.5. Serum Hcy concentrations in the offspring were measured by enzyme‐linked immunosorbent assay. Expressions of Hcy‐metabolism‐related enzymes, betaine‐Hcy methyltransferase, cystathionine β‐synthase, and methionine synthase, were measured by quantitative reverse transcription polymerase chain reaction and western blotting. Offspring were treated by either betaine or saline at the age of 8 weeks and serum Hcy concentrations were measured. Social behaviors were assessed by sniff‐duration test and three‐chamber test. Repetitive behavior was evaluated by marble‐burying test. Tail‐flick test was performed to measure nociceptive sensitivity.
Results
Prenatal VPA‐exposed mice showed significantly elevated Hcy concentrations and decreased betaine‐Hcy methyltransferase expression. Treatment with betaine could reduce Hcy level in VPA‐exposed mice, attenuate social impairment and repetitive behavior, and normalize nociceptive sensitivity in this model.
Conclusion
Betaine could ameliorate autism‐like features and play a beneficial role in a mouse autism model induced by prenatal VPA exposure.
The nonlinear dynamics of an optically injected semiconductor laser are explored for radio-over-fiber uplink transmission. Under optical injection locking, the laser at the base station is operated in the period-one oscillation state, where its intensity oscillates at a tunable microwave frequency. When the oscillation is tuned to the subcarrier frequency, it is further locked by the uplink microwave signal. By simply using an ordinary 2.5-Gbps-grade semiconductor laser, uplink transmission of the phase-shift keying (PSK) signal at a subcarrier of 16 GHz with bit-error rate of less than 10(-11) is demonstrated experimentally. Microwave PSK to optical PSK is achieved at the double-locked laser, which allows all-optical demodulation without any high-speed microwave electronics.
In this article, a simple, versatile, and mild method was used to fabricate porous enzyme microspheres using CaCO 3 microparticles as templates. The preparation process involved three steps including coprecipitation of enzyme with CaCO 3 , cross-linking, and template removal. The preparation process was optimized and the obtained porous horseradish peroxidase (HRP) microspheres (p-HRP) were characterized. The p-HRP exhibited improved thermal stability and was more stable under alkali conditions than its free counterpart. These features are attractive for practical applications. Compared to free HRP, the K m value of p-HRP was increased and the V max value was decreased. The catalytic performance of p-HRP in removing phenolic compound and dye from aqueous solution was explored by using phenol and Direct Black-38 as model substrates. The results indicated that p-HRP exhibited high removal efficiency and moderately good reusability.
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