76 research outputs found

    Kwanu Local – A High Yielding Traditional Maize Cultivar of Jaunsar Tribal Region of Uttarakhand and a Promising Genetic Resource for Maize Improvement

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    164-169Globally maize is the second most important crop in terms of acreage where as in India it ranks third after wheat and rice. Maize productivity has been breaking unprecedented barriers owing chiefly to wide scale cultivation of high yielding hybrids. Sustaining high yields of hybrids necessitates continued efforts for creation of novel gene assemblages and/or discovery of such naturally existing constellations. Traditional local cultivars are an important source of the latter. Kwanu Local is an example of such a traditional cultivar that contributes significantly towards sustaining food, fodder and fuel requirement of Jaunsari tribal community of Kwanu cluster in Dehradun district of Uttarakhand. It is a tall, high yielding, medium duration, semi-dent yellow bold-grained cultivar and owes its characteristic present form to multiple infusions from diverse populations that have taken place over the long history of its cultivation in the region. Its cultivation over a vast contiguous expanse and the selection practices followed by the farming community ensure maintenance of high heterozygosity in the population, assuring sustained high yields. The cultivar possesses many desirable features that make it a potential genetic resource for a variety of traits of agronomic importance (cob length, cob girth, number of kernels/row and kernel size). Its use for increasing kernel size has been well demonstrated. Kernel size in the backcross progenies involving inbreds VQL 1 (255 g) and V 400 (215 g) as recipients and Kwanu Local (343 g) as donor exhibited kernel size range of 260-293 g (VQL 1 x Kwanu Local) and 228-245 g (V 400 x Kwanu Local), showing increase of 6-14 and 2-15%, respectively, in the two crosses. With its local adaptability and high yield coupled with other desirable traits, Kwanu Local holds potential as a promising genetic resource for maize improvement

    G Protein Activation without a GEF in the Plant Kingdom

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    Animal heterotrimeric G proteins are activated by guanine nucleotide exchange factors (GEF), typically seven transmembrane receptors that trigger GDP release and subsequent GTP binding. In contrast, the Arabidopsis thaliana G protein (AtGPA1) rapidly activates itself without a GEF and is instead regulated by a seven transmembrane Regulator of G protein Signaling (7TM-RGS) protein that promotes GTP hydrolysis to reset the inactive (GDP-bound) state. It is not known if this unusual activation is a major and constraining part of the evolutionary history of G signaling in eukaryotes. In particular, it is not known if this is an ancestral form or if this mechanism is maintained, and therefore constrained, within the plant kingdom. To determine if this mode of signal regulation is conserved throughout the plant kingdom, we analyzed available plant genomes for G protein signaling components, and we purified individually the plant components encoded in an informative set of plant genomes in order to determine their activation properties in vitro. While the subunits of the heterotrimeric G protein complex are encoded in vascular plant genomes, the 7TM-RGS genes were lost in all investigated grasses. Despite the absence of a Gα-inactivating protein in grasses, all vascular plant Gα proteins examined rapidly released GDP without a receptor and slowly hydrolyzed GTP, indicating that these Gα are self-activating. We showed further that a single amino acid substitution found naturally in grass Gα proteins reduced the Gα-RGS interaction, and this amino acid substitution occurred before the loss of the RGS gene in the grass lineage. Like grasses, non-vascular plants also appear to lack RGS proteins. However, unlike grasses, one representative non-vascular plant Gα showed rapid GTP hydrolysis, likely compensating for the loss of the RGS gene. Our findings, the loss of a regulatory gene and the retention of the “self-activating” trait, indicate the existence of divergent Gα regulatory mechanisms in the plant kingdom. In the grasses, purifying selection on the regulatory gene was lost after the physical decoupling of the RGS protein and its cognate Gα partner. More broadly these findings show extreme divergence in Gα activation and regulation that played a critical role in the evolution of G protein signaling pathways

    Localization and broadband follow-up of the gravitational-wave transient GW150914

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    A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams

    Reactive oxygen species and male reproductive hormones

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    Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG) axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn could help in the management of male infertility

    Observation of Gravitational Waves from a Binary Black Hole Merger

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    On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 × 10−21. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410þ160 −180 Mpc corresponding to a redshift z ¼ 0.09þ0.03 −0.04 . In the source frame, the initial black hole masses are 36þ5 −4M⊙ and 29þ4 −4M⊙, and the final black hole mass is 62þ4 −4M⊙, with 3.0þ0.5 −0.5M⊙c2 radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger

    Localization and broadband follow-up of the gravitational-wave transient GW150914

    Get PDF
    A gravitational-wave transient was identified in data recorded by the Advanced LIGO detectors on 2015 September 14. The event candidate, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the gravitational wave data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network Circulars, giving an overview of the participating facilities, the gravitational wave sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the electromagnetic data and results of the electromagnetic follow-up campaign will be disseminated in the papers of the individual teams

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    Not AvailableGlobally maize is the second most important crop in terms of acreage where as in India it ranks third after wheat and rice. Maize productivity has been breaking unprecedented barriers owing chiefly to wide scale cultivation of high yielding hybrids. Sustaining high yields of hybrids necessitates continued efforts for creation of novel gene assemblages and/or discovery of such naturally existing constellations. Traditional local cultivars are an important source of the latter. Kwanu Local is an example of such a traditional cultivar that contributes significantly towards sustaining food, fodder and fuel requirement of Jaunsari tribal community of Kwanu cluster in Dehradun district of Uttarakhand. It is a tall, high yielding, medium duration, semi-dent yellow bold-grained cultivar and owes its characteristic present form to multiple infusions from diverse populations that have taken place over the long history of its cultivation in the region. Its cultivation over a vast contiguous expanse and the selection practices followed by the farming community ensure maintenance of high heterozygosity in the population, assuring sustained high yields. The cultivar possesses many desirable features that make it a potential genetic resource for a variety of traits of agronomic importance (cob length, cob girth, number of kernels/row and kernel size). Its use for increasing kernel size has been well demonstrated. Kernel size in the backcross progenies involving inbreds VQL 1 (255 g) and V 400 (215 g) as recipients and Kwanu Local (343 g) as donor exhibited kernel size range of 260-293 g (VQL 1 x Kwanu Local) and 228-245 g (V 400 x Kwanu Local), showing increase of 6-14 and 2-15%, respectively, in the two crosses. With its local adaptability and high yield coupled with other desirable traits, Kwanu Local holds potential as a promising genetic resource for maize improvement.Not Availabl
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