Expression of glucoamylase gene usingSUC2 promoter inSaccharomyces cerevisiae

Summary The cloning of glucoamylase geneSTA using theSUC2 promoter intoSaccharomyces cerevisiae was performed. The signal sequence ofSTA gene was used for the secretion of glucoamylase protein. The plasmid constructed in this way was named YEpSUCSTA and its expression was identified. The expression of YEpSUCSTA was repressed in the presence of glucose in growth medium, but derepressed when glucose became depleted. YEpSUCSTA showed the similar efficiency of glucoamylase secretion as YEpSTA-F which has the entireSTA gene. Glucoamylase activity in starch-glucose medium was largely increased because cell mass and plasmid stability were high in biosynthesis phase compared to extracellular glucoamylase activities in media which starch or glucose was the only carbon source.     

Direct fluorometric analysis of benzo(a)pyrene metabolite formation by mouse liver microsomes

We have examined the metabolites produced by in vitro incubation of benzo(a)pyrene with 3-methylcholanthrene-induced mice liver microsomes. Our objective was to observe directly a possible difference in microsomal enzyme systems of animal models having different susceptibility to chemical carcinogens. The metabolites produced by the two animal models,$\text{C57BL}\text{6J}$ and $\text{DBA}\text{2}$ mice, were analyzed by a highly sensitive, “three-dimensional” fluorescence plotting technique. The fluorescence spectra of the total ethyl acetate-soluble metabolites clearly indicate that the metabolites produced by $\text{DBA}\text{2}$ enzymes were predominantly monohydroxylated benzo(a)pyrene while those produced by the liver microsomes of $\text{C57BL}\text{6J}$ were highly enriched with the 7,8-dihydrodihydroxybenzo(a)pyrene type.     

Lab-scale study of an anaerobic membrane bioreactor (AnMBR) for dilute municipal wastewater treatment

Anaerobic bioreactors supplemented with membrane technology have become quite popular, owing to their favorable energy recovery characteristics. In this study, a lab-scale anaerobic Membrane Bioreactor (AnMBR) was assessed in experimental treatments of pre-settled dilute municipal wastewater obtained from a full-scaled wastewater treatment plant. The MBR system was operated in continuous flow mode for 440 days. To evaluate the performance of the AnMBR under various loading rates, the hydraulic retention time (HRT) was reduced in a stepwise manner (from 2 to 0.5 days). Afterward, the mixed liquor suspended solids (MLSS) were reduced from 7,000 to 3,000 mg/L in increments of 1,000 mg/L, resulting in a decrease in solids retention time (SRT) at a constant HRT of 1.0 day. The soluble chemical oxygen demand (SCOD) concentration in the feed varied between 38 and 131 mg/L, whereas the average permeate SCOD ranged between 18 and 37 mg/L, reflecting excellent effluent quality. The AnMBR performance in terms of COD removal proved stable, despite variations in influent characteristics and HRT and SRT changes. The concentration of extracellular polymeric substance (EPS) was reduced with decreases in HRT from 42 to 22 mg VS/mg of MLSS, thereby indicating that the increased biomass concentration biodegraded the EPS at lower HRTs. AnMBR is, therefore, demonstrably a feasible option for the treatment of dilute wastewater with separate stage nitrogen and phosphorus removal processes.     

Dopamine D3 Receptor Mediates Preadolescent Stress-Induced Adult Psychiatric Disorders

Several studies have shown that repeated stressful experiences during childhood increases the likelihood of developing depression- and anxiety-related disorders in adulthood; however, the underlying mechanisms are not well understood. We subjected drd3-EGFP and drd3-null mice to daily, two hour restraint stress episodes over a five day period during preadolescence (postnatal day 35 to 39), followed by social isolation. When these mice reached adulthood (post-natal day > 90), we assessed locomotor behavior in a novel environment, and assessed depression-related behavior in the Porsolt Forced Swim test. We also measured the expression and function of dopamine D3 receptor in limbic brain areas such as hippocampus, nucleus accumbens and amygdala in control and stressed drd3-EGFP mice in adulthood. Adult male mice subjected to restraint stress during preadolescence exhibited both anxiety- and depression-related behaviors; however, adult female mice subjected to preadolescent restraint stress exhibited only depression-related behaviors. The development of preadolescent stress-derived psychiatric disorders was blocked by D3 receptor selective antagonist, SB 277011-A, and absent in D3 receptor null mice. Adult male mice that experienced stress during preadolescence exhibited a loss of D3 receptor expression and function in the amygdala but not in hippocampus or nucleus accumbens. In contrast, adult female mice that experienced preadolescent stress exhibited increased D3 receptor expression in the nucleus accumbens but not in amygdala or hippocampus. Our results suggest that the dopamine D3 receptor is centrally involved in the etiology of adult anxiety- and depression-related behaviors that arise from repeated stressful experiences during childhood.     

Acetylcholinesterase distribution in chick spinal cord cultures

Summary Explants of 10–12 day chick embryo spinal cord were cultured by coverslip-roller tube method for 3–80 days. The cellular and subcellular localization of acetylcholinesterase activity in cultured neurons was studied by the thiocholine techniques of Karnovsky and Roots and Lewis and Shute.At the light microscopic level, acetylcholinesterase was demonstrated in the neurons of both ventral and dorsal horn regions. Occasionally neurons migrated in the outgrowth zone exhibited strong intracellular activity.At the electron microscopic level, acetylcholinesterase activity was found in the nuclear envelope, granular endoplasmic reticulum and the Golgi apparatus of the neurons. No enzyme reaction was detected in the glial cell cytoplasm.     

Strategically Functionalized Adenosines: Agonists for Adenosine Receptors

Abstract

The syntheses of three classes of adenosine analogues involving cyclosubstitution at the 6-position and functionalization at the 2-position are reported. The target molecules synthesized are stable with respect to hydrolytic deamination by mammalian adenosine deaminase, and, because of major structural changes at the 2- and 6-positions, these compounds are expected to be poor phosphorylation substrates for the kinases. Adenosine receptor binding data reveal that several of the compounds synthesized show excellent A₁ receptor affinity and A₂/A₁ selectivity.     

Caffeic Acid Phenethyl Ester Loaded in Microemulsions: Enhanced In Vitro Activity against Colon and Breast Cancer Cells and Possible Cellular Mechanisms

Food Biophysics - Caffeic acid phenethyl ester (CAPE) has high cytotoxicity against various cancer cells but has low water solubility and poor bioavailability. The objective of this work was to...     

An Antiaging Electrolyte Additive for High‐Energy‐Density Lithium‐Ion Batteries

High‐capacity Li‐rich layered oxide cathodes along with Si‐incorporated graphite anodes have high reversible capacity, outperforming the electrode materials used in existing commercial products. Hence, they are potential candidates for the development of high‐energy‐density lithium‐ion batteries (LIBs). However, structural degradation induced by loss of interfacial stability is a roadblock to their practical use. Here, the use of malonic acid‐decorated fullerene (MA‐C₆₀) with superoxide dismutase activity and water scavenging capability as an electrolyte additive to overcome the structural instability of high‐capacity electrodes that hampers the battery quality is reported. Deactivation of PF₅ by water scavenging leads to the long‐term stability of the interfacial structures of electrodes. Moreover, an MA‐C₆₀‐added electrolyte deactivates the reactive oxygen species and constructs an electrochemically robust cathode‐electrolyte interface for Li‐rich cathodes. This work paves the way for new possibilities in the design of electrolyte additives by eliminating undesirable reactive substances and tuning the interfacial structures of high‐capacity electrodes in LIBs.