1,398 research outputs found

    Spermatogonial Stem Cells (SSCs) in Buffalo (Bubalus bubalis) Testis

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    BACKGROUND: Water buffalo is an economically important livestock species and about half of its total world population exists in India. Development of stem cell technology in buffalo can find application in targeted genetic modification of this species. Testis has emerged as a source of pluripotent stem cells in mice and human; however, not much information is available in buffalo. OBJECTIVES AND METHODS: Pou5f1 (Oct 3/4) is a transcription factor expressed by pluripotent stem cells. Therefore, in the present study, expression of POU5F1 transcript and protein was examined in testes of both young and adult buffaloes by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemical analysis. Further, using the testis transplantation assay, a functional assay for spermatogonial stem cells (SSCs), stem cell potential of gonocytes/spermatogonia isolated from prepubertal buffalo testis was also determined. RESULTS: Expression of POU5F1 transcript and protein was detected in prepubertal and adult buffalo testes. Western blot analysis revealed that the POU5F1 protein in the buffalo testis exists in two isoforms; large (∼47 kDa) and small (∼21 kDa). Immunohistochemical analysis revealed that POU5F1 expression in prepubertal buffalo testis was present in gonocytes/spermatogonia and absent from somatic cells. In the adult testis, POU5F1 expression was present primarily in post-meiotic germ cells such as round spermatids, weakly in spermatogonia and spermatocytes, and absent from elongated spermatids. POU5F1 protein expression was seen both in cytoplasm and nuclei of the stained germ cells. Stem cell potential of prepubertal buffalo gonocytes/spermatogonia was confirmed by the presence of colonized DBA-stained cells in the basal membrane of seminiferous tubules of xenotransplanted mice testis. CONCLUSION/SIGNIFICANCE: These findings strongly indicate that gonocytes/spermatogonia, isolated for prepubertal buffalo testis can be a potential target for establishing a germ stem cell line that would enable genetic modification of buffaloes

    Simultaneous Screening of Multiple Mutations by Invader Assay Improves Molecular Diagnosis of Hereditary Hearing Loss: A Multicenter Study

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    Although etiological studies have shown genetic disorders to be a common cause of congenital/early-onset sensorineural hearing loss, there have been no detailed multicenter studies based on genetic testing. In the present report, 264 Japanese patients with bilateral sensorineural hearing loss from 33 ENT departments nationwide participated. For these patients, we first applied the Invader assay for screening 47 known mutations of 13 known deafness genes, followed by direct sequencing as necessary. A total of 78 (29.5%) subjects had at least one deafness gene mutation. Mutations were more frequently found in the patients with congenital or early-onset hearing loss, i.e., in those with an awareness age of 0–6 years, mutations were significantly higher (41.8%) than in patients with an older age of awareness (16.0%). Among the 13 genes, mutations in GJB2 and SLC26A4 were mainly found in congenital or early-onset patients, in contrast with mitochondrial mutations (12S rRNA m.1555A>G, tRNA(Leu(UUR)) m.3243A>G), which were predominantly found in older-onset patients. The present method of simultaneous screening of multiple deafness mutations by Invader assay followed by direct sequencing will enable us to detect deafness mutations in an efficient and practical manner for clinical use

    A New and Fast Technique to Generate Offspring after Germ Cells Transplantation in Adult Fish: The Nile Tilapia (Oreochromis niloticus) Model

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    Background: Germ cell transplantation results in fertile recipients and is the only available approach to functionally investigate the spermatogonial stem cell biology in mammals and probably in other vertebrates. In the current study, we describe a novel non-surgical methodology for efficient spermatogonial transplantation into the testes of adult tilapia (O. niloticus), in which endogenous spermatogenesis had been depleted with the cytostatic drug busulfan. Methodology/Principal Findings: Using two different tilapia strains, the production of fertile spermatozoa with donor characteristics was demonstrated in adult recipient, which also sired progeny with the donor genotype. Also, after cryopreservation tilapia spermatogonial cells were able to differentiate to spermatozoa in the testes of recipient fishes. These findings indicate that injecting germ cells directly into adult testis facilitates and enable fast generation of donor spermatogenesis and offspring compared to previously described methods. Conclusion: Therefore, a new suitable methodology for biotechnological investigations in aquaculture was established, with a high potential to improve the production of commercially valuable fish, generate transgenic animals and preserv

    Avoiding obscure topics and generalising findings produces higher impact research

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    Much academic research is never cited and may be rarely read, indicating wasted effort from the authors, referees and publishers. One reason that an article could be ignored is that its topic is, or appears to be, too obscure to be of wide interest, even if excellent scholarship produced it. This paper reports a word frequency analysis of 874,411 English article titles from 18 different Scopus natural, formal, life and health sciences categories 2009-2015 to assess the likelihood that research on obscure (rarely researched) topics is less cited. In all categories examined, unusual words in article titles associate with below average citation impact research. Thus, researchers considering obscure topics may wish to reconsider, generalise their study, or to choose a title that reflects the wider lessons that can be drawn. Authors should also consider including multiple concepts and purposes within their titles in order to attract a wider audience

    Autoregulation of the Drosophila Noncoding roX1 RNA Gene

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    Most genes along the male single X chromosome in Drosophila are hypertranscribed about two-fold relative to each of the two female X chromosomes. This is accomplished by the MSL (male-specific lethal) complex that acetylates histone H4 at lysine 16. The MSL complex contains two large noncoding RNAs, roX1 (RNA on X) and roX2, that help target chromatin modifying enzymes to the X. The roX RNAs are functionally redundant but differ in size, sequence, and transcriptional control. We wanted to find out how roX1 production is regulated. Ectopic DC can be induced in wild-type (roX1+ roX2+) females if we provide a heterologous source of MSL2. However, in the absence of roX2, we found that roX1 expression failed to come on reliably. Using an in situ hybridization probe that is specific only to endogenous roX1, we found that expression was restored if we introduced either roX2 or a truncated but functional version of roX1. This shows that pre-existing roX RNA is required to positively autoregulate roX1 expression. We also observed massive cis spreading of the MSL complex from the site of roX1 transcription at its endogenous location on the X chromosome. We propose that retention of newly assembled MSL complex around the roX gene is needed to drive sustained transcription and that spreading into flanking chromatin contributes to the X chromosome targeting specificity. Finally, we found that the gene encoding the key male-limited protein subunit, msl2, is transcribed predominantly during DNA replication. This suggests that new MSL complex is made as the chromatin template doubles. We offer a model describing how the production of roX1 and msl2, two key components of the MSL complex, are coordinated to meet the dosage compensation demands of the male cell

    Modafinil modulation of the default mode network

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    RationaleThe default mode network (DMN) is a functional network which is implicated in a range of cognitive processes. This network is proposed to consist of hubs located in the ventromedial prefrontal cortex (vmPFC), posterior cingulate/retrosplenial cortex (PCC/rSpl), and inferior parietal lobule (IPL), with other midline cortical and temporal lobe nodes connected to these hubs. How this network is modulated by neurochemical systems during functional brain activity is not yet understood.ObjectivesIn the present study, we used the norepinephrine/dopamine transporter inhibitor modafinil to test the hypothesis that this drug modulates the DMN.MethodsEighteen healthy right-handed adults participated in a double-blind, placebo-controlled study of single oral dose modafinil 200 mg. They performed a simple visual sensorimotor task during slow event-related fMRI. Drug effects were interrogated within the DMN defined by task-induced deactivation (TID) on placebo.ResultsThere was a trend toward faster reaction time (RT) on modafinil (Cohen's d = 0.38). Brain regions within the DMN which exhibited significant modafinil-induced augmentation of TID included vmPFC, PCC/rSpl, and left IPL. Across subjects, the modafinil effect on TID in the vmPFC was significantly and specifically associated with drug effects on RT speeding.ConclusionsModafinil augments TID in the DMN to facilitate sensorimotor processing speed, an effect which may be particularly dependent on changes in vmPFC activity. This is consistent with the gain control function of catecholamine systems and may represent an important aspect of the pro-cognitive effects of modafinil

    Plastisol Foaming Process. Decomposition of the Foaming Agent, Polymer Behavior in the Corresponding Temperature Range and Resulting Foam Properties

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    The decomposition of azodicarbonamide, used as foaming agent in PVC - plasticizer (1/1) plastisols was studied by DSC. Nineteen different plasticizers, all belonging to the ester family, two being polymeric (polyadipates), were compared. The temperature of maximum decomposition rate (in anisothermal regime at 5 K min-1 scanning rate), ranges between 434 and 452 K. The heat of decomposition ranges between 8.7 and 12.5 J g -1. Some trends of variation of these parameters appear significant and are discussed in terms of solvent (matrix) and viscosity effects on the decomposition reactions. The shear modulus at 1 Hz frequency was determined at the temperature of maximum rate of foaming agent decomposition, and differs significantly from a sample to another. The foam density was determined at ambient temperature and the volume fraction of bubbles was used as criterion to judge the efficiency of the foaming process. The results reveal the existence of an optimal shear modulus of the order of 2 kPa that corresponds roughly to plasticizer molar masses of the order of 450 ± 50 g mol-1. Heavier plasticizers, especially polymeric ones are too difficult to deform. Lighter plasticizers such as diethyl phthalate (DEP) deform too easily and presumably facilitate bubble collapse

    Search for Pair Production of Scalar Top Quarks Decaying to a tau Lepton and a b Quark in ppbar Collisions at sqrt{s}=1.96 TeV

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    We search for pair production of supersymmetric top quarks (~t_1), followed by R-parity violating decay ~t_1 -> tau b with a branching ratio beta, using 322 pb^-1 of ppbar collisions at sqrt{s}=1.96 TeV collected by the CDF II detector at Fermilab. Two candidate events pass our final selection criteria, consistent with the standard model expectation. We set upper limits on the cross section sigma(~t_1 ~tbar_1)*beta^2 as a function of the stop mass m(~t_1). Assuming beta=1, we set a 95% confidence level limit m(~t_1)>153 GeV/c^2. The limits are also applicable to the case of a third generation scalar leptoquark (LQ_3) decaying LQ_3 -> tau b.Comment: 7 pages, 2 eps figure

    Precision measurement of the top quark mass from dilepton events at CDF II

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    We report a measurement of the top quark mass, M_t, in the dilepton decay channel of ttˉb+νbˉνˉt\bar{t}\to b\ell'^{+}\nu_{\ell'}\bar{b}\ell^{-}\bar{\nu}_{\ell} using an integrated luminosity of 1.0 fb^{-1} of p\bar{p} collisions collected with the CDF II detector. We apply a method that convolutes a leading-order matrix element with detector resolution functions to form event-by-event likelihoods; we have enhanced the leading-order description to describe the effects of initial-state radiation. The joint likelihood is the product of the likelihoods from 78 candidate events in this sample, which yields a measurement of M_{t} = 164.5 \pm 3.9(\textrm{stat.}) \pm 3.9(\textrm{syst.}) \mathrm{GeV}/c^2, the most precise measurement of M_t in the dilepton channel.Comment: 7 pages, 2 figures, version includes changes made prior to publication by journa

    Measurement of the Ratios of Branching Fractions B(Bs -> Ds pi pi pi) / B(Bd -> Dd pi pi pi) and B(Bs -> Ds pi) / B(Bd -> Dd pi)

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    Using 355 pb^-1 of data collected by the CDF II detector in \ppbar collisions at sqrt{s} = 1.96 TeV at the Fermilab Tevatron, we study the fully reconstructed hadronic decays B -> D pi and B -> D pi pi pi. We present the first measurement of the ratio of branching fractions B(Bs -> Ds pi pi pi) / B(Bd -> Dd pi pi pi) = 1.05 pm 0.10 (stat) pm 0.22 (syst). We also update our measurement of B(Bs -> Ds pi) / B(Bd -> Dd pi) to 1.13 pm 0.08 (stat) pm 0.23 (syst) improving the statistical uncertainty by more than a factor of two. We find B(Bs -> Ds pi) = [3.8 pm 0.3 (stat) pm 1.3 (syst)] \times 10^{-3} and B(Bs -> Ds pi pi pi) = [8.4 pm 0.8 (stat) pm 3.2 (syst)] \times 10^{-3}.Comment: 7 pages, 2 figure
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