Transcriptional peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1α) regulates transformation of muscle fiber type in Schizothorax prenanti

Peroxisome proliferator-activated receptor γ coactivator (PGC)-1ɑ, a well-known member of PGC-1 transcriptional coactivator’s family, plays a key role in various metabolic pathways. Here, we investigated the role of PGC-1ɑ in the transformation of muscle fiber type in Schizothorax prenanti. The expression of PGC-1ɑ was induced in S. prenanti muscles following fasting. Following the induction of PGC-1ɑ, the expressions of mitochondrial-related enzyme cytochrome c oxidase (COX), citrate synthase (CS) and cytochrome c oxidase IV was also increased in white muscles, but the expression of carnitine palmitoyltransferase II (CPT II) has no change in this condition. Notably, when the levels of PGC-1ɑ was upregulated in the condition of fasting, muscle fibres type II showed the characteristics of muscle fibres type I, with expressed myosin heavy chain I (MyHC I) and myoglobin (Mb), and suppressed myosin heavy chain II (MyHC II) in response to fasting. Therefore, we can draw conclusion that PGC-1ɑ up-regulates slow fiber type formation during the transformation of muscle fiber type in S. prenanti.Keywords: PGC-1ɑ, muscle fiber type, transformation, Schizothorax prenanti, MyHC I, MyHC I

Strong-Field Nonsequential Double Ionization of Ar and Ne

We investigate the nonsequential double ionization (NSDI) of Ar and Ne based on quantitative rescattering theory (QRS). According to QRS theory, each elementary NSDI process can be calculated by multiplying the returning electron wave packet with appropriate differential electron-ion scattering cross sections. We include (e, 2e) and electron-impact excitation cross sections of Ar+ to obtain the correlated electron momentum spectra for the NSDI of Ar by few-cycle pulses to check the dependence of NSDI on the carrier-envelope phase. The results are compared to the ion momentum spectra from the recent experiment of Johnson [Phys. Rev. APLRAAN1050-294710.1103/ PhysRevA.83.013412 83, 013412 (2011)]. Calculations have also been performed for Ar at another intensity to illustrate the intensity dependence of NSDI and to compare with the earlier data of Feuerstein [Phys. Rev. Lett.PRLTAO0031-900710. 1103/PhysRevLett.87.043003 87, 043003 (2001)] and for Ne to illustrate the target dependence. We also address the presence of resonant capture processes in electron-ion collisions in the NSDI spectra

Calibration of distorted wave Born approximation for electron impact excitation of Ne and Ar at incident energies below 100 eV

We calibrate the distorted wave Born approximation (DWBA) for electron impact excitation processes empirically. Differential cross sections (DCS) for the excitation of the $2p^53s$, $2p^53p$,$2p^54s$, and $2p^54p$ configurations of Ne and the $3p^54s$ and $3p^54p$ configurations of Ar by electron impact are calculated using DWBA for incident energies between 20 and 100 eV. The calculated results are compared with the absolute experimental measurements and other theoretical results. We found that the structure of the DCS can be well reproduced by the DWBA model while the magnitude is overestimated for most cases considered here. The differences in magnitude between DWBA and experiment are used to test the calibration of DWBA such that the DWBA can be used to describe laser-induced electron impact excitation processes. These processes are involved in the non-sequential double ionization of atoms in strong laser fields.Comment: 10 pages, 8 figure

Electromagnetic Wave Theory and Remote Sensing

Contains reports on eight research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)National Science Foundation (Grant ECS82-03390)Schlumberger-Doll Research CenterNational Aeronautics and Space Administration (Contract NAG5-141)National Aeronautics and Space Administration (Contract NAS5-26861)National Aeronautics and Space Administration (Contract NAG5-270)U.S. Navy - Office of Naval Research (Contract N00014-83-K-0258)International Business Machines, Inc

Electromagnetic Wave Theory and Applications

Contains reports on eleven research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)Joint Services Electronics Program (Contract DAAL03-86-K-0002)National Science Foundation (Grant ECS82-03390)National Science Foundation (Grant ECS85-04381)Schlumberger-Doll Research CenterNational Aeronautics and Space Administration (Contract NAG 5-141)National Aeronautics and Space Administration (Contract NAS 5-26861)National Aeronautics and Space Administration (Contract NAG 5-270)U.S. Navy - Office of Naval Research (Contract N00014-83-K-0258)National Aeronautics and Space Administration (Contract NAG 5-725)International Business Machines, Inc.Lincoln Laborator

PGC-1α is associated with Schizothorax prenanti myoblast differentiation

PGC-1α has been considered as an important mediator of functional capacity of muscle. Our previous study indicated that the mRNA level of PGC-1α increased in muscle during Schizothorax prenanti (S. prenanti) growth. To understand the biological significance of PGC-1α up-regulation, S. prenanti myosatellite cells were isolated and the function of PGC-1α in myoblast differentiation was further investigated. The results indicated that PGC-1α over-expressing transfectants fused to form myotubes with higher mRNA level of myosin heavy chain isoform I (MyHCI). No obvious differentiation was observed in PGC-1α-targeted shRNA-transfected cells with a marked decrement of MyHCI expression. Furthermore, S. prenanti PGC-1α increased the expression of MyoD and MyoG, which controlled the commitment of precursor cells to myotubes. In contrast, the levels of MyoD and MyoG mRNA were down-regulated with shRNA-targeting PGC-1α transfection. These investigations indicate that PGC-1α is associated with myoblast differentiation and it elevates MyoD and MyoG expression levels in S. prenanti myoblast cells

Knockdown of LXRα Inhibits Goat Intramuscular Preadipocyte Differentiation

Goat intramuscular fat (IMF) content is mainly determined by the processes of intramuscular preadipocytes adipogenic differentiation and mature adipocyte lipid accumulation. However, the underlying regulators of these biological processes remain largely unknown. Here, we report that the expression of Liver X receptor alpha (LXRα) reaches a peak at early stage and then gradually decreases during goat intramuscular adipogenesis. Knockdown of LXRα mediated by two independent siRNAs significantly inhibits intramuscular adipocytes lipid accumulation and upregulates preadipocytes marker- preadipocyte factor 1 (pref1) expression. Consistently, siRNA treatments robustly decrease mRNA level of adipogenic related genes, including CCAAT enhancer binding protein alpha (Cebpα), Peroxisome proliferator activated receptor gamma (Pparg), Sterol regulatory element binding protein isoform 1c (Srebp1c), Fatty acids binding protein (aP2) and Lipoprotein lipase (Lpl). Next, adenovirus overexpression of LXRα does not affect intramuscular adipocytes adipogenesis manifested by Oil Red O signal measurement and adipogenic specific genes detection. Mechanically, we found that both CCAAT enhancer binding protein beta (Cebpβ) and Kruppel like factor 8 (Klf8) are potential targets of LXRα, indicated by having putative binding sites of LXRα at the promoter of these genes and similar expression pattern during adipogenesis comparing to LXRα. Importantly, mRNA levels of Cebpβ and Klf8 are downregulated significantly in goat LXRα knockdown intramuscular adipocyte. These results demonstrate that loss function of LXRα inhibits intramuscular adipogenesis possibly through down-regulation of Cebpβ and Klf8. Our research will provide new insights into mechanical regulation of goat IMF deposition

Comparative analysis of tissue expression and methylation reveal the crucial hypoxia genes in hypoxia resistant animals

Tibetan goat and Tibetan sheep are species peculiar to Qinghai-Tibetan Plateau which is the highest plateau in the world, and have high hypoxia resistance to the extremely bad environment. Unlike monogastrics, how the genes change responding to hypoxia in ruminants remains unclear. In the present study, three healthy animals of every breeds, including Tibetan sheep, Tibetan goat, Chuanzhong goat and Small-Tailed Han sheep were selected. The expression of factor inhibiting HIF 1 (FIH-1), hypoxia inducible factor 1α (HIF-1α), HIF-3α and erythropoietin (EPO) in various tissues, including heart, liver, lungs, kidney, muscle and brain, were investigated. EPO was observed highly expressed in all the tissues of Tibetan goats and Tibetan sheep compared with low-altitude animals respectively, implied that higher expression of EPO may give the explanation for the hypoxia resistance of plateau animals. Besides, we also cloned the promoters of FIH-1, HIF-1α, HIF-3α and EPO in goats and sheep, analyzed their core regions and CpG islands. Higher methylation rate was observed in HIF-1α, HIF-3α and EPO, while lower methylation rate hit on FIH-1. These data may be beneficial for revealing the response mechanism to hypoxia of plateau animals.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author