Radio-frequency exposure of the yellow fever mosquito (A. aegypti) from 2 to 240 GHz

Fifth generation networks (5G) will be associated with a partial shift to higher carrier frequencies, including wavelengths comparable in size to insects. This may lead to higher absorption of radio frequency (RF) electromagnetic fields (EMF) by insects and could cause dielectric heating. The yellow fever mosquito (Aedes aegypti), a vector for diseases such as yellow and dengue fever, favors warm climates. Being exposed to higher frequency RF EMFs causing possible dielectric heating, could have an influence on behavior, physiology and morphology, and could be a possible factor for introduction of the species in regions where the yellow fever mosquito normally does not appear. In this study, the influence of far field RF exposure on A. aegypti was examined between 2 and 240 GHz. Using Finite Difference Time Domain (FDTD) simulations, the distribution of the electric field in and around the insect and the absorbed RF power were found for six different mosquito models (three male, three female). The 3D models were created from micro-CT scans of real mosquitoes. The dielectric properties used in the simulation were measured from a mixture of homogenized A. aegypti. For a given incident RF power, the absorption increases with increasing frequency between 2 and 90 GHz with a maximum between 90 and 240 GHz. The absorption was maximal in the region where the wavelength matches the size of the mosquito. For a same incident field strength, the power absorption by the mosquito is 16 times higher at 60 GHz than at 6 GHz. The higher absorption of RF power by future technologies can result in dielectric heating and potentially influence the biology of this mosquito.     

Optimization of simultaneous production of tyrosinase and laccase by Neurospora crassa

Increasing demand for efficient and environmentally benign oxidation technologies has resulted in a focus on the use of oxidoreductases. Laccases and tyrosinases, which utilize molecular oxygen and produce water as by-product, are particularly attractive. Simultaneous production of laccase and tyrosinase was studied in Neurospora crassa FGSC #321 as the fungal strain which has the ability to produce tyrosinase intracellularly while producing laccase extracellularly. Using one-variable-at-a-time experiments and a Taguchi orthogonal L9 array demonstrated that a Vogel minimal medium containing 2.5% sucrose at pH 6.5 and 25?°C with no agitation or oxygen purging were the optimum conditions for N. crassa FGSC #321 growth. Conditions were adjusted to obtain the highest laccase and tyrosinase production. Results indicate that the control mechanisms for the production of both enzymes in N. crassa FGSC #321 are similar but not necessarily identical. Results revealed that transferring the harvested cells from the growth medium into the phosphate buffer (pH 6.8, 0.1M) containing cycloheximide (2?μM) and fluorouracil (2?mM) and increasing the temperature to 30?°C were the best conditions for simultaneous production of laccase and tyrosinase (1278 and 410?U/g of biomass, respectively). Nonetheless, starvation at 35?°C is proposed as the most cost-effective means for inducing laccase. The N. crassa laccase was characterized by using its molecular weight, pI value, optimal pH and temperature and stability.     

A potent peroxidase from solid cell culture of Ocimum basilicum with high sensitivity for blood glucose determination

Extensive applications of peroxidase (POX) have raised the global market demand at a considerable rate during the forecast period of 2020–2025. Nonetheless, the large-scale POX preparation still relies on the extraction from agricultural products, while there is an accumulative driving force toward employing biotechnological processes with agricultural hassle free identity. Consequently, a novel heme peroxidase was purified to homogeneity (MW of 40 kD) from the callus culture of basil in darkness on Murashige-Skoog medium supplemented by 2,4-dichlorophenoxyacetic acid (10^–6 M) and kinetin (10^–5 M). The highest activity of the purified peroxidase (ObPOX) was observed in Tris-base buffer at pH 7.5 and 80 °C. ObPOX showed high stability over pH(s) 5 to 7.5 and temperatures of 15 to 60 °C. ObPOX specific activity was 1245.142 AU mg^?1 in the presence of phenol, 4 times higher than that of HRP. ObPOX showed moderate affinity for guaiacol (K_m?=?21.5 mM), but obtained an exceptionally high specificity constant (k_cat/K_m?=?66,743.7 s^?1 M^?1) for GASA (4-[(4-Hydroxy-3-methoxyphenyl) azo]-benzenesulfonic acid), the introduced substrate for determination of blood sugar. Applying ObPOX instead of HRP in glucose measurements of the real samples improved the regression constant of the correlation diagram between the tests and the lab results from 0.958 to 0.981. Physicochemical properties of ObPOX as well as the growth rate of basil callus (5.04 g L^?1 per day) and the yield of ObPOX production (35 mg per 100 g dry biomass per subculture) designates O. basilicum cell culture for large-scale production of a robust peroxidase.