Prenatal ketamine exposure causes abnormal development of prefrontal cortex in rat.

Ketamine is commonly used for anesthesia and as a recreational drug. In pregnant users, a potential neurotoxicity in offspring has been noted. Our previous work demonstrated that ketamine exposure of pregnant rats induces affective disorders and cognitive impairments in offspring. As the prefrontal cortex (PFC) is critically involved in emotional and cognitive processes, here we studied whether maternal ketamine exposure influences the development of the PFC in offspring. Pregnant rats on gestational day 14 were treated with ketamine at a sedative dose for 2 hrs, and pups were studied at postnatal day 0 (P0) or P30. We found that maternal ketamine exposure resulted in cell apoptosis and neuronal loss in fetal brain. Upon ketamine exposure in utero, PFC neurons at P30 showed more dendritic branching, while cultured neurons from P0 PFC extended shorter neurites than controls. In addition, maternal ketamine exposure postponed the switch of NR2B/2A expression, and perturbed pre- and postsynaptic protein expression in the PFC. These data suggest that prenatal ketamine exposure impairs neuronal development of the PFC, which may be associated with abnormal behavior in offsprings

Enhanced Steroid Metabolites Production by Resting Cell Phytosterol Bioconversion

The steroid metabolites 9-hydroxy-androstenedione (9-OH-AD), androstadienedione (ADD) and androstenedione (AD) are important steroidal pharmaceuticals. In order to raise the production of steroid metabolites, an efficient resting cell phytosterol bioconversion process was developed to produce 9-OH-AD in the presence of hydroxypropyl-β-cyclodextrin (HP-β-CD). Cell growth medium containing phytosterol as an inducer positively improved cell activity. Under aerobic conditions, bioconversion proceeded at 70 g L–1 phytosterol in the presence of HP-β-CD (the optimized molar ratio of HP-β-CD/phytosterol was 1:1) with 30 g L–1 resting Mycobacterium neoaurum NwIB-yV cells (cell dry mass) in a 5-L bioreactor, where 9-OH-AD production and space-time yield reached 36.4 g L–1 and 9.1 g L–1 d–1, respectively. The recycling of cells and HP-β-CD enables cost-saving and industrial applications. This bioprocess was also applied for the production of ADD and AD. The production of these steroid metabolites was much higher than that reported in previous studies

Antibunching photons in a cavity coupled to an optomechanical system

We study the photon statistics of a cavity linearly coupled to an optomechanical system via second order correlation functions. Our calculations show that the cavity can exhibit strong photon antibunching even when optomechanical interaction in the optomechanical system is weak. The cooperation between the weak optomechanical interaction and the destructive interference between different paths for two-photon excitation leads to the efficient antibunching effect. Compared with the standard optomechanical system, the coupling between a cavity and an optomechanical system provides a method to relax the constraints to obtain single photon by optomechanical interaction.Comment: 7 papes, 5 figure

High-level Production of Bovine Enterokinase Light Chain Using Fed-batches by Recombinant Pichia pastoris

A recombinant Pichia pastoris containing enterokinase light chain gene from bovine was cultured in flasks firstly at different pH, methanol addition, and cell mass concentration for enterokinase production. Activity of enterokinase increased as cell mass concentration increased at more than γ = 6 % methanol added. No significant change of activity of enterokinase was observed when methanol added was less than γ = 4 %. No activity of enterokinase lost after 120 h conservation at different pH. Secondly, high-level enterokinase production was achieved in 3.7 L bioreactor at pH 4.0, γ = 0.6 % methanol, p = 52.5 kPa. Activity of enterokinase was not cell mass concentration dependent at γ = 0.6 % methanol in bioreactor. Yield of enterokinase was 479.99 mg L–1 after 97.5 h induction. Maintenance coefficient and methanol consumed were calculated to analyse the enterokinase production