Endothelin-1 impairs skeletal muscle myogenesis and development via ETB receptors and p38 MAPK signaling pathway.

Myopenia is a condition marked by progressive decline of muscle mass and strength and is associated with aging or obesity. It poses the risk of falling, with potential bone fractures, thereby also increasing the burden on family and society. Skeletal muscle wasting is characterized by a reduced number of myoblasts, impaired muscle regeneration and increased muscle atrophy markers (Atrogin-1, MuRF-1). Endothelin-1 (ET-1) is a potent vasoconstrictor peptide. Increased circulating levels of ET-1 is noted with aging and is associated with muscular fibrosis and decline of strength. However, the regulatory mechanism controlling its effect on myogenesis and atrophy remains unknown. In the present study, the effects of ET-1 on myoblast proliferation, differentiation and development were investigated in C2C12 cells and in ET-1-infused mice. The results show that ET-1, acting via ETB receptors, reduced insulin-stimulated cell proliferation, and also reduced MyoD, MyoG and MyHC expression in the differentiation processes of C2C12 myoblasts. ET-1 inhibited myoblast differentiation through ETB receptors and the p38 mitogen-activated protein kinase (MAPK)-dependent pathway. Additionally, ET-1 decreased MyHC expression in differentiated myotubes. Inhibition of proteasome activity by MG132 ameliorated the ET-1-stimulated protein degradation in differentiated C2C12 myotubes. Furthermore, chronic ET-1 infusion caused skeletal muscle atrophy and impaired exercise performance in mice. In conclusion, ET-1 inhibits insulin-induced cell proliferation, impairs myogenesis and induces muscle atrophy via ETB receptors and the p38 MAPK-dependent pathway.

Spin State Disproportionation in Insulating Ferromagnetic LaCoO3 Epitaxial Thin Films.

The origin of insulating ferromagnetism in epitaxial LaCoO3 films under tensile strain remains elusive despite extensive research efforts are devoted. Surprisingly, the spin state of its Co ions, the main parameter of its ferromagnetism, is still to be determined. Here, the spin state in epitaxial LaCoO3 thin films is systematically investigated to clarify the mechanism of strain-induced ferromagnetism using element-specific X-ray absorption spectroscopy and dichroism. Combining with the configuration interaction cluster calculations, it is unambiguously demonstrated that Co3+ in LaCoO3 films under compressive strain (on LaAlO3 substrate) is practically a low-spin state, whereas Co3+ in LaCoO3 films under tensile strain (on SrTiO3 substrate) have mixed high-spin and low-spin states with a ratio close to 1:3. From the identification of this spin state ratio, it is inferred that the dark strips observed by high-resolution scanning transmission electron microscopy indicate the position of Co3+ high-spin state, i.e., an observation of a spin state disproportionation in tensile-strained LaCoO3 films. This consequently explains the nature of ferromagnetism in LaCoO3 films. The study highlights the importance of spin state degrees of freedom, along with thin-film strain engineering, in creating new physical properties that do not exist in bulk materials.

Additive manufacturing of Schwann cell-laden collagen/alginate nerve guidance conduits by freeform reversible embedding regulate neurogenesis via exosomes secretion towards peripheral nerve regeneration.

Peripheral nerve injury is a common clinical problem that could be debilitating to one's quality of life. The complex nerve guidance conduits (NGCs) with cells in order to improve nerve regeneration. Therefore, we used freeform reversible embedding of suspended hydrogels to fabricate Schwann cells (SCs)-laden collagen/alginate (Col/Alg) NGCs. First, we evaluated Col influence on the characteristics of NGCs. After which, Wharton's jelly mesenchymal stem cells (WJMSC) are seeded onto the inner channel of NGCs and evaluated neural regeneration behaviors. Results indicated the SCs-laden NGCs with 2.5 % Col found the highest proliferation and secretion of neurotrophic protein. Furthermore, co-culture of SCs promoted differentiation of WJMSC as seen from the increased neurogenic-related protein in NGCs. To determine the molecular mechanism between SCs and WJMSC, we demonstrated the neurotrophic factors secreted by SCs act on tropomyosin receptor kinase A (TrkA) receptors of WJMSC to promote nerve regeneration. In addition, our study demonstrated SCs-derived exosomes had a critical role in regulating neural differentiation of WJMSC. Taken together, this study demonstrates the fabrication of SCs-laden Col/Alg NGCs for nerve regeneration and understanding regarding the synergistic regenerative mechanisms of different cells could bring us a step closer for clinical treatment of large nerve defects.

Impedimetric investigation of dual electrical properties of reduced graphene-oxide-based biosensors in the detection of dopamine.

Because of the properties of high charge mobility, large detection area and chemical stability of graphene, it has been applied in many biomedical applications. Graphene oxide (GO) with abundant oxygenated functional groups is easily to form an aqueous suspension by sonication. Here, the exposed areas on the patterned-circuit silicon-based chips were first modified by (3-aminopropyl) trimethoxysilane (APTMS) for later chemically immobilized GO. After that, solution-based reduction process using hydrazine was used to gain reduced GO (RGO)-based biosensors. ESCA survey spectra showed oxygen-containing functional groups of GO decreased from 47% to 5.7%, 4.1%, 3.8%, and 3.6% under varied reduction times of 30 min, 40 min, 50 min, and 60 min, respectively. D/G intensity ratio (ID/IG) in Raman spectra showed 1.03 after 60-min reduction process. The 60-min reduction process was further used in the electrical sensing experiments. Since different deposited layers of graphene were obtained in our experimental processes, 60-min-RGO-based biosensors have been found that those immobilized RGO possessed semiconductive property as the layers are less than 11. By contrary, when the layers were above 11, the immobilized RGO would resemble metallic material. In addition, the impedimetric analyses indicated obvious signal responses above 86 kHz and showed a concentration-dependent trend in dopamine sensing in physiological phosphate buffered saline (PBS) using 60-min-RGO-based biosensors which were feature of semiconductor.

Microwave-Assisted Direct Thioesterification of Carboxylic Acids.

A one-pot synthesis of thioesters directly from carboxylic acids, N,N'-diphenylthiourea, triethylamine, and primary alkyl halides is described. Microwave-assisted heating and a catalytic amount of 4-(dimethylamino)pyridine (DMAP) further improved the yields. Both aromatic and aliphatic carboxylic acids were converted to the corresponding thioesters, and many functional groups were compatible with this reaction. Several possible reaction intermediates were investigated, and the quaternary ammonium salts, derived from alkyl halides and tertiary amines, were the intermediates to yield thioesters. A new reaction mechanism for this thioesterification is proposed.

Magnetic Properties of Cluster Glassy Ni/NiO Core-Shell Nanoparticles: an Investigation of Their Static and Dynamic Magnetization.

We review the phenomenology of the exchange bias and its related effects in core-shell nanocrystals. The static and dynamic properties of the magnetization for ferromagnetic Ni-core and antiferromagnetic NiO-shell cluster glassy nanoparticles are examined, along with the pinning-depinning process, through the measurement of the conventional exchange bias, and associated with different cooling fields and particle sizes. Two significant indexes for the dipolar interaction n and multi-anisotropic barrier ß derived from the dynamic magnetization are proposed, which provide a unified picture of the exchange bias mechanism and insight into the influence of the cooling field.

A highly selective and turn-on fluorescence sensor for detection of cyanide.

2-Hydroxy-1-naphthaldehyde (receptor 1) serves as a selective chemosensor for cyanide anion (CN(-)). In the presence of CN(-), an enhanced fluorescent intensity and red shift were observed. The observed complexation between receptor 1 and CN(-) may cause from a formation of phenoxide anion by nucleophilic addition of the CN(-) to carbonyl group.

Investigation of the interfacial effects of small chemical-modified TiO2 nanotubes on 3T3 fibroblast responses.

In order to gain insight into how interfacial effects influence cell responses, chemically modified anodized TiO2 nanotubes (ATNs) were used to simultaneously investigate the effects of nanoscale substrate structure and angstrom-scale chemicals on cell morphological change and cell growth. Two small chemicals were used to modify the ATNs, namely, 3-aminopropyltrimethoxysilane (APTMS) and 3-mercaptopropyltrimethoxysilane (MPTMS), resulting in APTMS-modified ATNs (APTMS-ATNs) and MPTMS-modified ATNs (MPTMS-ATNs), respectively. In our in vitro observation of NIH/3T3 fibroblasts, cells thrived on both unmodified and modified ATNs. Quantitative analyses of cell numbers exhibited that APTMS-ATNs effectively facilitated cell proliferation and directed cell orientation owing to full cell-substrate contact caused by positively charged amino groups (-NH3(+)) on the surface. In addition, scanning electron microscopy and fluorescence images showed different cell morphologies on APTMS-ATNs and MPTMS-ATNs. APTMS-ATNs resulted in flat spreading of fibroblasts, while MPTMS-ATNs resulted in fibroblasts with a three-dimensional solid shape and clear contours. The results indicate that the synergistic effects of nanotube surface topology and small chemical modification and, to a lesser extent, surface hydrophilicity, alter the interfacial interactions between cells and substrates, significantly affecting cell morphology, attachment, and growth. Using ATNs with different interfacial effects from various small chemicals, orientation of cells into various patterns can be achieved and investigation of cell fates, such as proliferation or stem cell differentiation, can be performed for future advanced medical or biological applications.

Diacylglycerol lipase regulates lifespan and oxidative stress response by inversely modulating TOR signaling in Drosophila and C. elegans.

Target of rapamycin (TOR) signaling is a nutrient-sensing pathway controlling metabolism and lifespan. Although TOR signaling can be activated by a metabolite of diacylglycerol (DAG), phosphatidic acid (PA), the precise genetic mechanism through which DAG metabolism influences lifespan remains unknown. DAG is metabolized to either PA via the action of DAG kinase or 2-arachidonoyl-sn-glycerol by diacylglycerol lipase (DAGL). Here, we report that in Drosophila and Caenorhabditis elegans, overexpression of diacylglycerol lipase (DAGL/inaE/dagl-1) or knockdown of diacylglycerol kinase (DGK/rdgA/dgk-5) extends lifespan and enhances response to oxidative stress. Phosphorylated S6 kinase (p-S6K) levels are reduced following these manipulations, implying the involvement of TOR signaling. Conversely, DAGL/inaE/dagl-1 mutants exhibit shortened lifespan, reduced tolerance to oxidative stress, and elevated levels of p-S6K. Additional results from genetic interaction studies are consistent with the hypothesis that DAG metabolism interacts with TOR and S6K signaling to affect longevity and oxidative stress resistance. These findings highlight conserved metabolic and genetic pathways that regulate aging.

A quinoline derivative as an efficient sensor to detect selectively Al³âº ion.

A quinoline-based Schiff base 1 has been utilized as a fluorescence chemosensor for the selective detection of Al(3+). The receptor 1 exhibited a high association constant (3.67 × 10(5) M(-1)) with submicromolar detection limit (0.18 ppm) towards Al(3+) in CH3CN solution.

The comparative chloroplast genomic analysis of photosynthetic orchids and developing DNA markers to distinguish Phalaenopsis orchids.

The chloroplast genome of Phalaenopsis equestris was determined and compared to those of Phalaenopsis aphrodite and Oncidium Gower Ramsey in Orchidaceae. The chloroplast genome of P. equestris is 148,959 bp, and a pair of inverted repeats (25,846 bp) separates the genome into large single-copy (85,967 bp) and small single-copy (11,300 bp) regions. The genome encodes 109 genes, including 4 rRNA, 30 tRNA and 75 protein-coding genes, but loses four ndh genes (ndhA, E, F and H) and seven other ndh genes are pseudogenes. The rate of inter-species variation between the two moth orchids was 0.74% (1107 sites) for single nucleotide substitution and 0.24% for insertions (161 sites; 1388 bp) and deletions (189 sites; 1393 bp). The IR regions have a lower rate of nucleotide substitution (3.5-5.8-fold) and indels (4.3-7.1-fold) than single-copy regions. The intergenic spacers are the most divergent, and based on the length variation of the three intergenic spacers, 11 native Phalaenopsis orchids could be successfully distinguished. The coding genes, IR junction and RNA editing sites are relatively more conserved between the two moth orchids than between those of Phalaenopsis and Oncidium spp.

Spontaneous self-organization of Cu2O/CuO core-shell nanowires from copper nanoparticles.

We report on the formation and spontaneous self-organization of Cu(2)O/CuO core-shell nanowires from individual copper nanoparticles. The growth process is interpreted using the results of time-dependent in situ x-ray diffraction. High-resolution transmission electron microscopy is used to observe the intermediate state of pearl-necklace-like aggregates that form a chain-like configuration of Cu(2)O nanoparticles intertwined into nanowires. The existence of an amorphous CuO shell is confirmed by the XANES technique and explained through an intensity simulation using a proposed core-shell nanowire model.