Characterization of Basal and Morphine-Induced Uridine Release in the Striatum: An In Vivo Microdialysis Study in Mice

Uridine, a pyrimidine nucleoside, has been proposed to be a potential signaling molecule in the central nervous system. The understanding of uridine release in the brain is therefore of fundamental importance. The present study was performed to determine the characteristics of basal and morphine-induced uridine release in the striatum of freely moving mice by using the microdialysis technique. To ascertain whether extracellular uridine was derived from neuronal release, the following criteria were applied: sensitivity to (a) K⁺ depolarization, (b) Na⁺ channel blockade and (c) removal of extracellular Ca²⁺. Uridine levels were not greatly affected by infusion of tetrodotoxin (TTX) and were unaffected by either Ca²⁺-free medium or in the presence of EGTA (a calcium chelator), suggesting that basal extracellular uridine levels were maintained mainly by non-vesicular release mechanisms. In addition, both systemic and local application of morphine increased striatal uridine release. The morphine-induced release was reversed by naloxone pretreatment, but was unaffected by TTX or EGTA infusion. Moreover, co-administration of morphine and nitrobenzylthioinosine (NBTI, an inhibitor of nucleotide transporter) produced increases of uridine levels similar to that produced by NBTI or morphine alone, suggesting a nucleotide transporter mechanism involved. Taken together, these findings suggest that morphine produces a μ-opioid receptor-mediated uridine release via nucleoside transporters in a TTX- and calcium-independent manner.     

Actinoplanes hulinensis sp. nov., a novel actinomycete isolated from soybean root (Glycine max (L.) Merr)

A novel actinomycete, designated strain NEAU-M9^T, was isolated from soybean root (Glycine max (L.) Merr) and characterized using a polyphasic approach. 16S rRNA gene sequence similarity studies showed that strain NEAU-M9^T belonged to the genus Actinoplanes, being most closely related to Actinoplanes campanulatus DSM 43148^T (98.85 %), Actinoplanes capillaceus DSM 44859^T (98.70 %), Actinoplanes lobatus DSM 43150^T (98.30 %), Actinoplanes auranticolor DSM 43031^T (98.23 %) and Actinoplanes sichuanensis 03-723^T (98.06 %); similarity to other type strains of the genus Actinoplanes ranged from 95.87 to 97.56 %. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that the isolate formed a distinct phyletic line with A. campanulatus DSM 43148^T and A. capillaceus DSM 44859^T. This branching pattern was also supported by the tree constructed with the maximum-likelihood method. However, the low level of DNA–DNA relatedness allowed the isolate to be differentiated from the above-mentioned two Actinoplanes species. Moreover, strain NEAU-M9^T could also be distinguished from the most closely related species by morphological, physiological and characteristics. Therefore, it is proposed that strain NEAU-M9^T represents a novel Actinoplanes species, Actinoplanes hulinensis sp. nov. The type strain of Actinoplanes hulinensis is NEAU-M9^T (= CGMCC 4.7036^T = DSM 45728^T).     

Features of Pro-σK Important for Cleavage by SpoIVFB,an Intramembrane Metalloprotease

Intramembrane proteases regulate diverse processes by cleaving substrates within a transmembrane segment or near the membrane surface. Bacillus subtilis SpoIVFB is an intramembrane metalloprotease that cleaves Pro-σ^K during sporulation. To elucidate features of Pro-σ^K important for cleavage by SpoIVFB, coexpression of the two proteins in Escherichia coli was used along with cell fractionation. In the absence of SpoIVFB, a portion of the Pro-σ^K was peripherally membrane associated. This portion was not observed in the presence of SpoIVFB, suggesting that it serves as the substrate. Deletion of Pro-σ^K residues 2 to 8, addition of residues at its N terminus, or certain single-residue substitutions near the cleavage site impaired cleavage. Certain multiresidue substitutions near the cleavage site changed the position of cleavage, revealing preferences for a small residue preceding the cleavage site N-terminally (i.e., at the P1 position) and a hydrophobic residue at the second position following the cleavage site C-terminally (i.e., P2′). These features appear to be conserved among Pro-σ^K orthologs. SpoIVFB did not tolerate an aromatic residue at P1 or P2′ of Pro-σ^K. A Lys residue at P3′ of Pro-σ^K could not be replaced with Ala unless a Lys was provided farther C-terminally (e.g., at P9′). α-Helix-destabilizing residues near the cleavage site were not crucial for SpoIVFB to cleave Pro-σ^K. The preferences and tolerances of SpoIVFB are somewhat different from those of other intramembrane metalloproteases, perhaps reflecting differences in the interaction of the substrate with the membrane and the enzyme.     

Surface Properties and Corrosion Behavior of Co–Cr Alloy Fabricated with Selective Laser Melting Technique

We sought to study the corrosion behavior and surface properties of a commercial cobalt–chromium (Co–Cr) alloy which was fabricated with selective laser melting (SLM) technique. For this purpose, specimens were fabricated using different techniques, such as SLM system and casting methods. Surface hardness testing, microstructure observation, surface analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test were carried out to evaluate the corrosion properties and surface properties of the specimens. We found that microstructure of SLM specimens was more homogeneous than that of cast specimens. The mean surface hardness values of SLM and cast specimens were 458.3 and 384.8, respectively; SLM specimens showed higher values than cast ones in hardness. Both specimens exhibited no differences in their electrochemical corrosion properties in the artificial saliva through potentiodynamic curves and EIS, and no significant difference via XPS. Therefore, we concluded that within the scope of this study, SLM-fabricated restorations revealed good surface properties, such as proper hardness, homogeneous microstructure, and also showed sufficient corrosion resistance which could meet the needs of dental clinics.     

Structural Evolution Design and Optimization for the Metamaterials with Broadband Frequency-Independent Negative Permeability

Plasmonics - Broadband frequency-independent operations are strongly desired in metamaterial applications. In this work, we unveil the roles of each element acting in the metamaterial unit with a...     

MicroRNA-32 targeting PTEN enhances M2 macrophage polarization in the glioma microenvironment and further promotes the progression of glioma

Molecular and Cellular Biochemistry - T cells are involved in bone marrow failure in aplastic anemia (AA). MEG3 is a long, non-coding RNA that can modulate target gene expression and T cell...     

High-sorgoleone producing sorghum genetic stocks suppress soil nitrification and N2O emissions better than low-sorgoleone producing genetic stocks

Plant and Soil - Rapid nitrification leads to loss of nitrogen (N) fertilizer in agricultural systems. Plant produced/derived biological nitrification inhibitors (BNIs) are an effective...