Changes in skeletal muscle gene expression following clenbuterol administration

BACKGROUND: Beta-adrenergic receptor agonists (BA) induce skeletal muscle hypertrophy, yet specific mechanisms that lead to this effect are not well understood. The objective of this research was to identify novel genes and physiological pathways that potentially facilitate BA induced skeletal muscle growth. The Affymetrix platform was utilized to identify gene expression changes in mouse skeletal muscle 24 hours and 10 days after administration of the BA clenbuterol. RESULTS: Administration of clenbuterol stimulated anabolic activity, as indicated by decreased blood urea nitrogen (BUN; P < 0.01) and increased body weight gain (P < 0.05) 24 hours or 10 days, respectively, after initiation of clenbuterol treatment. A total of 22,605 probesets were evaluated with 52 probesets defined as differentially expressed based on a false discovery rate of 10%. Differential mRNA abundance of four of these genes was validated in an independent experiment by quantitative PCR. Functional characterization of differentially expressed genes revealed several categories that participate in biological processes important to skeletal muscle growth, including regulators of transcription and translation, mediators of cell-signalling pathways, and genes involved in polyamine metabolism. CONCLUSION: Global evaluation of gene expression after administration of clenbuterol identified changes in gene expression and overrepresented functional categories of genes that may regulate BA-induced muscle hypertrophy. Changes in mRNA abundance of multiple genes associated with myogenic differentiation may indicate an important effect of BA on proliferation, differentiation, and/or recruitment of satellite cells into muscle fibers to promote muscle hypertrophy. Increased mRNA abundance of genes involved in the initiation of translation suggests that increased levels of protein synthesis often associated with BA administration may result from a general up-regulation of translational initiators. Additionally, numerous other genes and physiological pathways were identified that will be important targets for further investigations of the hypertrophic effect of BA on skeletal muscle

Про авторів

Paleotethys was a highly mobile oceanic realm pinching into the supercontinent Pangea between Gondwana and Eurasia in the late Paleozoic/early Mesozoic. Published Paleotethyan reconstructions reveal that the time of Paleotethys closure and the position of its suture are highly debated. We present new magmatic and detrital zircon ages, separated from pre-Alpine basement and Permian to Triassic cover rocks exposed in the External Hellenides of Crete. These age data reveal Variscan and Cimmerian docking of microplates along the southern margin of Laurasia and help to constrain the time of Paleotethys closure.46% of detrital zircons from quartzite in the Variscan basement, are Pennsylvanian with concordant ages at 321. ±. 2. Ma, 310. ±. 3. Ma, and 300. ±. 3. Ma. The basement is unconformably overlain by arc-related volcanics of the Tyros Unit, magmatic zircons of which yielded a concordant U-Pb zircon age at 285. ±. 2. Ma. Thus, the metasediments of the basement, interpreted as former trench sediments, were deposited, metamorphosed and exhumed in latest Carboniferous to early Permian times (302-283. Ma). Magmatic activity during this late Variscan phase is also indicated by igneous boulders within Olenekian (meta)conglomerates of the Tyros Unit, which yielded concordant U-Pb zircon ages at 291. ±. 2 and 310. ±. 2. Ma. The late Variscan orogenic phase is attributed to the collision of the Gondwana-derived southern Minoan terrane (SMT) with Laurasia subsequent to northward subduction of Paleotethys lithosphere and Viséan collision of the northern Minoan terrane (NMT).Magmatic activity ceased during the late Permian, but revived in the Lower Triassic as is indicated by felsic volcanics (249. ±. 2. Ma, concordant U-Pb zircon) and by detrital zircons (242. ±. 3, 240. ±. 5. Ma, 237. ±. 3. Ma concordant U-Pb zircon) of the Tyros Unit. At the same time the Variscan chain was exhumed and removed as is shown by the detritus in the Lower to Middle Triassic Tyros sediments, which includes high-grade metamorphic rocks and detrital zircons with U-Pb ages ranging from 280 to 335. Ma.A significant change in the detrital components occurred in the Ladinian when the Variscan basement with its Permo-Triassic cover was thrust on top of clastic sediments, today represented by the Phyllite-Quartzite Unit s.str. The Phyllite-Quartzite Unit s.str. shows Cadomian and older - but no Variscan - detritus because of its position along the northern margin of the Cimmerian ribbon continent. Thus, in the eastern Mediterranean, Paleotethys was closed during the Ladinian and the related suture in the External Hellenides is situated between the Variscan basement (active margin in the north) and the Phyllite-Quartzite Unit s.str (passive margin in the south). Carnian crustal extension led to subsidence of the Variscan/Cimmerian chain, most parts of which merged below sea level. This is the reason why 90% of the detritus of the Carnian Tyros Beds are not related to the Variscan, but to the Cadomian and Grenvillian basement of the E-Gondwana derived Cimmerian ribbon continent

The proton and deuteron F_2 structure function at low Q^2

Measurements of the proton and deuteron $F_2$ structure functions are presented. The data, taken at Jefferson Lab Hall C, span the four-momentum transfer range $0.06 < Q^2 < 2.8$ GeV$^2$, and Bjorken $x$ values from 0.009 to 0.45, thus extending the knowledge of $F_2$ to low values of $Q^2$ at low $x$. Next-to-next-to-leading order calculations using recent parton distribution functions start to deviate from the data for $Q^2<2$ GeV$^2$ at the low and high $x$-values. Down to the lowest value of $Q^2$, the structure function is in good agreement with a parameterization of $F_2$ based on data that have been taken at much higher values of $Q^2$ or much lower values of $x$, and which is constrained by data at the photon point. The ratio of the deuteron and proton structure functions at low $x$ remains well described by a logarithmic dependence on $Q^2$ at low $Q^2$.Comment: 3 figures, submitted pape

Longitudinal-Transverse Separations of Structure Functions at Low Q2Q^{2} for Hydrogen and Deuterium

We report on a study of the longitudinal to transverse cross section ratio, $R=\sigma_L/\sigma_T$, at low values of $x$ and $Q^{2}$, as determined from inclusive inelastic electron-hydrogen and electron-deuterium scattering data from Jefferson Lab Hall C spanning the four-momentum transfer range 0.06 $< Q^{2} < 2.8$ GeV$^{2}$. Even at the lowest values of $Q^{2}$, $R$ remains nearly constant and does not disappear with decreasing $Q^{2}$, as expected. We find a nearly identical behaviour for hydrogen and deuterium.Comment: 4 pages, 2 gigure

Using estrus detection patches to optimally time insemination improved pregnancy risk in suckled beef cows enrolled in a fixed-time artificial insemination program

Citation: Hill, S. L., Grieger, D. M., Olson, K. C., Jaeger, J. R., Dahlen, C. R., Bridges, G. A., . . . Stevenson, J. S. (2016). Using estrus detection patches to optimally time insemination improved pregnancy risk in suckled beef cows enrolled in a fixed-time artificial insemination program. Journal of Animal Science, 94(9), 3703-3710. doi:10.2527/jas2016-0469A multilocation study examined pregnancy risk (PR) after delaying AI in suckled beef cows from 60 to 75 h when estrus had not been detected by 60 h in response to a 7-d CO-Synch + progesterone insert (CIDR) timed AI (TAI) program (d-7: CIDR insert concurrent with an injection of GnRH; d 0: PGF(2 alpha) injection and removal of CIDR insert; and GnRH injection at TAI [ 60 or 75 h after CIDR removal]). A total of 1,611 suckled beef cows at 15 locations in 9 states (CO, IL, KS, MN, MS, MT, ND, SD, and VA) were enrolled. Before applying the fixed-time AI program, BCS was assessed, and blood samples were collected. Estrus was defined to have occurred when an estrus detection patch was >50% colored (activated). Pregnancy was determined 35 d after AI via transrectal ultrasound. Cows (n = 746) detected in estrus by 60 h (46.3%) after CIDR removal were inseminated and treated with GnRH at AI (Control). Remaining nonestrous cows were allocated within location to 3 treatments on the basis of parity and days postpartum: 1) GnRH injection and AI at 60 h (early-early = EE; n = 292), 2) GnRH injection at 60 h and AI at 75 h (early-delayed = ED; n = 282), or 3) GnRH injection and AI at 75 h (delayed-delayed = DD; n = 291). Control cows had a greater (P < 0.01) PR (64.2%) than other treatments (EE = 41.7%, ED = 52.8%, DD = 50.0%). Use of estrus detection patches to delay AI in cows not in estrus by 60 h after CIDR insert removal (ED and DD treatments) increased (P < 0.05) PR to TAI when compared with cows in the EE treatment. More (P < 0.001) cows that showed estrus by 60 h conceived to AI at 60 h than those not showing estrus (64.2% vs. 48.1%). Approximately half (49.2%) of the cows not in estrus by 60 h had activated patches by 75 h, resulting in a greater (P < 0.05) PR than their nonestrous herd mates in the EE (46.1% vs. 34.5%), ED (64.2% vs. 39.2%), and DD (64.8% vs. 31.5%) treatments, respectively. Overall, cows showing estrus by 75 h (72.7%) had greater (P < 0.001) PR to AI (61.3% vs. 37.9%) than cows not showing estrus. Use of estrus detection patches to allow for a delayed AI in cows not in estrus by 60 h after removal of the CIDR insert improved PR to TAI by optimizing the timing of the AI in those cows

Search for single vector-like quarks in ppbar collisions at sqrt(s) = 1.96 TeV

We present a search for hypothetical vector-like quarks in ppbar collisions at sqrt(s) = 1.96 TeV. The data were collected by the D0 detector at the Fermilab Tevatron Collider and correspond to an integrated luminosity of 5.4 fb^(-1). We select events with a final state composed of a W or Z boson and a jet consistent with a heavy object decay. We observe no significant excess in comparison to the background prediction and set limits on production cross sections for vector-like quarks decaying to W+jet and Z+jet. These are the most stringent mass limits for electroweak single vector-like quark production at hadron colliders.Comment: submitted to Phys. Rev. Let

Measurement of the top quark pair production cross section in the lepton+jets channel in proton-antiproton collisions at s\sqrt{s}=1.96 TeV

We present a measurement of the inclusive top quark pair production cross section in \ppbar collisions at (\sqrt{s}=1.96) TeV utilizing data corresponding to an integrated luminosity of \lumi\ collected with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing one high-$p_{T}$ isolated electron or muon and at least two jets, and we perform three analyses: one exploiting specific kinematic features of \ttbar events, the second using $b$-jet identification, and the third using both techniques to separate \ttbar\ signal from background. In the third case, we determine simultaneously the $t\bar{t}$ cross section and the ratio of the production rates of $W$+heavy flavor jets and $W$+light flavor jets, which reduces the impact of the systematic uncertainties related to the background estimation. Assuming a top quark mass of 172.5 GeV, we obtain $\sigma_{t\bar{t}} = 7.78^{+0.77}_{-0.64}$ pb. This result agrees with predictions of the standard model.Comment: 19 pages, 6 figures, submitted to Phys. Rev.

Search for new fermions ("quirks") at the Fermilab Tevatron Collider

We report results of a search for particles with anomalously high ionization in events with a high transverse energy jet and large missing transverse energy in $2.4$ fb$^{-1}$ of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron $p\bar{p}$ collider. Production of such particles (quirks) is expected in scenarios with extra QCD-like {\it SU(N)} sectors, and this study is the first dedicated search for such signatures. We find no evidence of a signal and set a lower mass limit of 107 ~GeV for the mass of a charged quirk with strong dynamics scale $\Lambda$ in the range from 10 keV to 1 MeV.Comment: submitted to Phys. Rev. Letter

Evidence for an anomalous like-sign dimuon charge asymmetry

We measure the charge asymmetry A of like-sign dimuon events in 6.1 fb(-1) of p (p) over bar collisions recorded with the D0 detector at a center-of-mass energy root s = 1.96 TeV at the Fermilab Tevatron collider. From A, we extract the like-sign dimuon charge asymmetry in semileptonic b-hadron decays: A(sl)(b) = -0.00957 +/- 0.00251 (stat) +/- 0.00146 (syst). This result differs by 3.2 standard deviations from the standard model prediction A(sl)(b)(SM) = (-2.3(0.6)(+0.5)) x 10(-4) and provides first evidence of anomalous CP violation in the mixing of neutral B mesons