18 research outputs found

    Alternaria and Cercospora leaf spot diseases of Niger (Guizotia Abyssinica Cass.) – a traditional tribal crop of South Gujarat, India, with cost benefit ratio in relation to different fungicides

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    Niger (Guizotia abyssinica Cass.) is an important minor oil seed crop grown in dry areas grown mostly by tribal and interior places as life line of tribal segment. Tribal people mainly use its oil for cooking purpose, above than that there were also other uses. Hence, the niger crop should be protected from the infection. The crop is affected by number of fungal diseases. Therefore, a field experiment was formulated for three years with the four replications at the Niger Research Station (NRS) at Navsari Agricultural University (NAU), Vanarasi, Navsari (Gujarat) on the foliar diseases of GN-1 variety of niger crop. In this experiment, six different fungicides along with one control have been evaluated to control the Alternaria and Cercospora leaf spot diseases, out of which all the fungicidal treatments were significantly superior over the control. Here, foliar spray on the incidence of diseases was compared with the control (without any treatment). All the fungicidal treatments were significantly superior over the control to reduce Alternaria and Cercospora leaf spot diseases of Niger crop. Treatment of Carbendazim + Mancozeb (0.2 %) with two sprays first from the initiation of the disease and second after the interval of 15 days recorded the lowest incidence of Alternaria (14.56) and Cercospora (14.94) leaf spot diseases of niger and recorded the highest seed yield 337 seed yield kg/ha along with the net return with cost benefit ratio graph

    Seed yield increase in Niger crop in to relation to honeybee and other pollinators

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    Niger (Guizotia abyssinica Cass) is an important minor oilseed crop of hilly and tribal regions and it is used for oil as well as for various other purposes only by the tribal people. Therefore, a systematic study was arranged to document about the increase in the seed yield of niger crop in relation to honeybees (Aphis mellifera), as a pollinator in niger crop with paired plot technique at the Niger Research Station (NRS) at Navsari Agricultural University (NAU) and at farmer’s field, Vanarasi, Navsari, Gujarat (India) and also studied its relation in terms of cost benefit ratio (CB). The trial was conducted at Niger Research Station (NRS), Vanarasi for 3 years (2013- 14, 2014-15 and 2015-16) and also at farmer's field to ascertain the role and involvement of honey bees (Aphis mellifera) in swelling the seed yield of niger crop (due to pollination) and its effect on income due to increase in the niger seed yield. Significant differences were observed for number of capitula/plant, number of seeds/capitula, 1000 seed weight and seed yield in both the location for the consecutive 3 years. However, the seed yield and gross returns were considerably higher in first location of T1 Natural plot/ open pollinated with beehive (Aphis mellifera) in all the 3 years data with the maximum seed yield with the gross return was obtained in this treatment

    Structure, dynamics and RNA binding of the multi-domain splicing factor TIA-1.

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    Alternative pre-messenger ribonucleic acid (pre-mRNA) splicing is an essential process in eukaryotic gene regulation. The T-cell intracellular antigen-1 (TIA-1) is an apoptosis-promoting factor that modulates alternative splicing of transcripts, including the pre-mRNA encoding the membrane receptor Fas. TIA-1 is a multi-domain ribonucleic acid (RNA) binding protein that recognizes poly-uridine tract RNA sequences to facilitate 5' splice site recognition by the U1 small nuclear ribonucleoprotein (snRNP). Here, we characterize the RNA interaction and conformational dynamics of TIA-1 by nuclear magnetic resonance (NMR), isothermal titration calorimetry (ITC) and small angle X-ray scattering (SAXS). Our NMR-derived solution structure of TIA-1 RRM2-RRM3 (RRM2,3) reveals that RRM2 adopts a canonical RNA recognition motif (RRM) fold, while RRM3 is preceded by an non-canonical helix α0. NMR and SAXS data show that all three RRMs are largely independent structural modules in the absence of RNA, while RNA binding induces a compact arrangement. RRM2,3 binds to pyrimidine-rich FAS pre-mRNA or poly-uridine (U9) RNA with nanomolar affinities. RRM1 has little intrinsic RNA binding affinity and does not strongly contribute to RNA binding in the context of RRM1,2,3. Our data unravel the role of binding avidity and the contributions of the TIA-1 RRMs for recognition of pyrimidine-rich RNAs

    Rational design of cyclic peptide inhibitors of U2AF homology motif (UHM) domains to modulate pre-mRNA splicing.

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    U2AF homology motifs (UHMs) are atypical RNA recognition motif domains that mediate critical protein-protein interactions during the regulation of alternative pre-mRNA splicing and other processes. The recognition of UHM domains by UHM ligand motif (Ulm) peptide sequences plays important roles during early steps of spliceosome assembly. Splicing factor 45 kDa (SPF45) is an alternative splicing factor implicated in breast and lung cancers, and splicing regulation of apoptosis-linked pre-mRNAs by SPF45 was shown to depend on interactions between its UHM domain and Ulm motifs in constitutive splicing factors. We have developed cyclic peptide inhibitors that target UHM domains. By screening a focused library of linear and cyclic peptides and performing structure-activity relationship analysis, we designed cyclic peptides with 4-fold improved binding affinity for the SPF45 UHM domain compared to native Ulm ligands and 270-fold selectivity to discriminate UHM domains from alternative and constitutive splicing factors. These inhibitors are useful tools to modulate and dissect mechanisms of alternative splicing regulation

    Identification of phenothiazine derivatives as UHM-binding inhibitors of early spliceosome assembly.

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    Interactions between U2AF homology motifs (UHMs) and U2AF ligand motifs (ULMs) play a crucial role in early spliceosome assembly in eukaryotic gene regulation. UHM-ULM interactions mediate heterodimerization of the constitutive splicing factors U2AF65 and U2AF35 and between other splicing factors that regulate spliceosome assembly at the 3′ splice site, where UHM domains of alternative splicing factors, such as SPF45 and PUF60, contribute to alternative splicing regulation. Here, we performed high-throughput screening using fluorescence polarization assays with hit validation by NMR and identified phenothiazines as general inhibitors of UHM-ULM interactions. NMR studies show that these compounds occupy the tryptophan binding pocket of UHM domains. Co-crystal structures of the inhibitors with the PUF60 UHM domain and medicinal chemistry provide structure-activity-relationships and reveal functional groups important for binding. These inhibitors inhibit early spliceosome assembly on pre-mRNA substrates in vitro. Our data show that spliceosome assembly can be inhibited by targeting UHM-ULM interactions by small molecules, thus extending the toolkit of splicing modulators for structural and biochemical studies of the spliceosome and splicing regulation

    Structural model of the dimeric Parkinson's protein LRRK2 reveals a compact architecture involving distant interdomain contacts.

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    Leucine-rich repeat kinase 2 (LRRK2) is a large, multidomain protein containing two catalytic domains: a Ras of complex proteins (Roc) G-domain and a kinase domain. Mutations associated with familial and sporadic Parkinson's disease (PD) have been identified in both catalytic domains, as well as in several of its multiple putative regulatory domains. Several of these mutations have been linked to increased kinase activity. Despite the role of LRRK2 in the pathogenesis of PD, little is known about its overall architecture and how PD-linked mutations alter its function and enzymatic activities. Here, we have modeled the 3D structure of dimeric, full-length LRRK2 by combining domain-based homology models with multiple experimental constraints provided by chemical cross-linking combined with mass spectrometry, negative-stain EM, and small-angle X-ray scattering. Our model reveals dimeric LRRK2 has a compact overall architecture with a tight, multidomain organization. Close contacts between the N-terminal ankyrin and C-terminal WD40 domains, and their proximity-together with the LRR domain-to the kinase domain suggest an intramolecular mechanism for LRRK2 kinase activity regulation. Overall, our studies provide, to our knowledge, the first structural framework for understanding the role of the different domains of full-length LRRK2 in the pathogenesis of PD
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