1,772 research outputs found

    Examination of Parental Effect on the Progeny Diapause by Reciprocal Cross Test in the Cabbage Beetle, Colaphellus bowringi

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    The cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae), a serious pest of crucifers in China, undergoes summer or winter diapause in the soil as an adult. In the present study, the incidence of diapause were measured in reciprocal crosses between a high—diapause strain (HD strain) and a laboratory—selected nondiapausing strain (ND strain) under different photoperiods and temperatures, to explore parental influences on the progeny diapause. Sensitivity to photoperiod in the selected nondiapausing strain was nearly eliminated at 25 °C, whereas sensitivity to temperature of the selected nondiapausing strain was retained under continuous darkness at 20 and 22 °C. Reciprocal crosses between the HD strain and the ND strain showed that the incidence of diapause in the progeny was always intermediate to that of the parents under different photoperiods and temperatures, suggesting that diapause induction was determined by both female and male parents. There was a significant effect of temperature; temperature interacted with reciprocal cross on diapause induction, whereas no significant effect of reciprocal cross was demonstrated. The incidence of diapause in ♀ND × ♂HD was the same as in ♀HD × ♂ND under continuous darkness at 18 °C (100%) and 26 °C (0%), but the former was higher than that in ♀HD × ♂ND under continuous darkness at 22 °C, suggesting that female parent does not exhibit strong influence on the diapause response to temperature. There was a significant effect of photoperiod and reciprocal cross on diapause induction, whereas no significant interactive effect on diapause induction was demonstrated. Incidence of diapause in ♀HD × ♂ND was always higher than in ♀ND × ♂HD at 25 °C and 12:12 L:D, 14:10 L:D, and 16:8 L:D, suggesting a strong maternal influence on the diapause response to photoperiod, though a significant difference was observed only at 14:10 L:D. Our results support the idea that diapause induction is determined by both female and male parents. However, results also indicated that a strong maternal influence on diapause was exhibited only in response to photoperiod

    Chemo- and Thermosensory Responsiveness of Grueneberg Ganglion Neurons Relies on Cyclic Guanosine Monophosphate Signaling Elements

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    Neurons of the Grueneberg ganglion (GG) in the anterior nasal region of mouse pups respond to cool temperatures and to a small set of odorants. While the thermosensory reactivity appears to be mediated by elements of a cyclic guanosine monophosphate (cGMP) cascade, the molecular mechanisms underlying the odor-induced responses are unclear. Since odor-responsive GG cells are endowed with elements of a cGMP pathway, specifically the transmembrane guanylyl cyclase subtype GC-G and the cyclic nucleotide-gated ion channel CNGA3, the possibility was explored whether these cGMP signaling elements may also be involved in chemosensory GG responses. Experiments with transgenic mice deficient for GC-G or CNGA3 revealed that GG responsiveness to given odorants was significantly diminished in these knockout animals. These findings suggest that a cGMP cascade may be important for both olfactory and thermosensory signaling in the GG. However, in contrast to the thermosensory reactivity, which did not decline over time, the chemosensory response underwent adaptation upon extended stimulation, suggesting that the two transduction processes only partially overlap. Copyright (C) 2011 S. Karger AG, Base

    RNA polymerase II stalling promotes nucleosome occlusion and pTEFb recruitment to drive immortalization by Epstein-Barr virus

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    Epstein-Barr virus (EBV) immortalizes resting B-cells and is a key etiologic agent in the development of numerous cancers. The essential EBV-encoded protein EBNA 2 activates the viral C promoter (Cp) producing a message of ~120 kb that is differentially spliced to encode all EBNAs required for immortalization. We have previously shown that EBNA 2-activated transcription is dependent on the activity of the RNA polymerase II (pol II) C-terminal domain (CTD) kinase pTEFb (CDK9/cyclin T1). We now demonstrate that Cp, in contrast to two shorter EBNA 2-activated viral genes (LMP 1 and 2A), displays high levels of promoter-proximally stalled pol II despite being constitutively active. Consistent with pol II stalling, we detect considerable pausing complex (NELF/DSIF) association with Cp. Significantly, we observe substantial Cp-specific pTEFb recruitment that stimulates high-level pol II CTD serine 2 phosphorylation at distal regions (up to +75 kb), promoting elongation. We reveal that Cp-specific pol II accumulation is directed by DNA sequences unfavourable for nucleosome assembly that increase TBP access and pol II recruitment. Stalled pol II then maintains Cp nucleosome depletion. Our data indicate that pTEFb is recruited to Cp by the bromodomain protein Brd4, with polymerase stalling facilitating stable association of pTEFb. The Brd4 inhibitor JQ1 and the pTEFb inhibitors DRB and Flavopiridol significantly reduce Cp, but not LMP1 transcript production indicating that Brd4 and pTEFb are required for Cp transcription. Taken together our data indicate that pol II stalling at Cp promotes transcription of essential immortalizing genes during EBV infection by (i) preventing promoter-proximal nucleosome assembly and ii) necessitating the recruitment of pTEFb thereby maintaining serine 2 CTD phosphorylation at distal regions

    Nitrogen and sulphur management: challenges for organic sources in temperate agricultural systems

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    A current global trend towards intensification or specialization of agricultural enterprises has been accompanied by increasing public awareness of associated environmental consequences. Air and water pollution from losses of nutrients, such as nitrogen (N) and sulphur (S), are a major concern. Governments have initiated extensive regulatory frameworks, including various land use policies, in an attempt to control or reduce the losses. This paper presents an overview of critical input and loss processes affecting N and S for temperate climates, and provides some background to the discussion in subsequent papers evaluating specific farming systems. Management effects on potential gaseous and leaching losses, the lack of synchrony between supply of nutrients and plant demand, and options for optimizing the efficiency of N and S use are reviewed. Integration of inorganic and organic fertilizer inputs and the equitable re-distribution of nutrients from manure are discussed. The paper concludes by highlighting a need for innovative research that is also targeted to practical approaches for reducing N and S losses, and improving the overall synchrony between supply and demand

    Parity-Violating Electron Scattering from 4He and the Strange Electric Form Factor of the Nucleon

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    We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from ^4He at an average scattering angle = 5.7 degrees and a four-momentum transfer Q^2 = 0.091 GeV^2. From these data, for the first time, the strange electric form factor of the nucleon G^s_E can be isolated. The measured asymmetry of A_PV = (6.72 +/- 0.84 (stat) +/- 0.21 (syst) parts per million yields a value of G^s_E = -0.038 +/- 0.042 (stat) +/- 0.010 (syst), consistent with zero

    Factors affecting the outcome of surgically treated non-iatrogenic traumatic cervical esophageal perforation: 28 years experience at a single center

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    <p>Abstract</p> <p>Background</p> <p>We reviewed our experience with non-iatrogenic traumatic cervical esophageal perforations, paying particular attention to factors affecting the outcome of such cases.</p> <p>Methods</p> <p>In total, 30 patients treated surgically between 1980 and 2008 for non-iatrogenic traumatic cervical esophageal perforation in our clinic were reviewed.</p> <p>Results</p> <p>There were 25 male and 5 female patients with a median age of 27.5 years. The type of injury was external trauma in 21 (70%) patients and endoluminal injury in the remaining 9 (30%) patients. The mechanism of injury was gunshot in 16 patients, stabbing in 4, falling in 1 (extraluminal injury), and foreign body in 9 (endoluminal injuries). The overall mortality rate was 16.6% (5/30). The mortality rate for extraluminal injuries was 19%, and for endoluminal injuries was 11.1%. Mortality in patients treated within 24 h of sustaining injury was substantially less than in those for whom diagnosis and treatment were delayed (12.5 and 21.4%, respectively). The mortality rate was 33.3% (3/9) for patients with tracheal injuries and 9.5% (2/21) for those without tracheal injuries.</p> <p>Conclusions</p> <p>A treatment delay greater than 24 h, the presence of tracheal injury, or extraluminal perforation significantly affected the outcome of surgically treated non iatrogenic traumatic cervical esophageal perforation.</p

    Endothelium Derived Nitric Oxide Synthase Negatively Regulates the PDGF-Survivin Pathway during Flow-Dependent Vascular Remodeling

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    Chronic alterations in blood flow initiate structural changes in vessel lumen caliber to normalize shear stress. The loss of endothelial derived nitric oxide synthase (eNOS) in mice promotes abnormal flow dependent vascular remodeling, thus uncoupling mechanotransduction from adaptive vascular remodeling. However, the mechanisms of how the loss of eNOS promotes abnormal remodeling are not known. Here we show that abnormal flow-dependent remodeling in eNOS knockout mice (eNOS (−/−)) is associated with activation of the platelet derived growth factor (PDGF) signaling pathway leading to the induction of the inhibitor of apoptosis, survivin. Interfering with PDGF signaling or survivin function corrects the abnormal remodeling seen in eNOS (−/−) mice. Moreover, nitric oxide (NO) negatively regulates PDGF driven survivin expression and cellular proliferation in cultured vascular smooth muscle cells. Collectively, our data suggests that eNOS negatively regulates the PDGF-survivin axis to maintain proportional flow-dependent luminal remodeling and vascular quiescence
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