Publications by authors named "Subramani Rajkumar"

Doubled haploid (DH) technology has accelerated the development of inbreds in maize. Worldwide, breeding efforts have led to the development of diverse maternal haploid inducer (HI) lines adapted to temperate and tropical conditions. So far, no HI line adapted to subtropical conditions has been developed.

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Objectives: A composite core collection (CCC) in sesame (Sesamum indicum L.) will help utilize genetic resources efficiently. This study reports, using genomics tools, a representative minimal set (CCC) that capture maximal genetic diversity from a set of 5,856 sesame accessions being conserved at the National Genebank (NGB) of the ICAR-NBPGR.

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Unlabelled: Diverse haploid inducer lines with > 6% of haploid induction rate are now routinely used to develop doubled haploid lines. Though gene regulates haploid induction, its molecular characterization and haplotype analysis in maize and its related species have not been undertaken so far. In the present study, the entire 1812 bp long gene was sequenced among two mutant and eight wild-type inbreds.

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Sesame (Sesamum indicum L.) is an ancient oilseed crop belonging to the family Pedaliaceae and a globally cultivated crop for its use as oil and food. In this study, 2496 sesame accessions, being conserved at the National Genebank of ICAR-National Bureau of Plant Genetic Resources (NBPGR), were genotyped using genomics-assisted double-digest restriction-associated DNA sequencing (ddRAD-seq) approach.

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Article Synopsis
  • * A genome analysis of five amaranth species revealed that repetitive sequences, primarily Long Terminal Repeat (LTR) elements, made up a significant portion of their genomes, with repeat content varying between 54.49% to 63.26%.
  • * The phylogenetic analysis indicated close genetic relationships between certain species and distinct classifications for dioecious species, providing crucial insights to identify key genes for agricultural improvement and genomic studies.
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  • The study focused on creating a long-term storage method for pollen from specific plant species to help enhance crop improvement.
  • Different species required different pollen germination media, with varying sucrose concentrations found to be optimal.
  • Cryopreservation at -196°C proved to maintain pollen viability effectively for two months, offering a reliable technique for long-term pollen storage and its application in agriculture.
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Unlabelled: The genome size variation is an important attribute in evolutionary and species characterization. L. is regarded as one of the taxonomically complicated genera within the order Zingiberales, with more than 75 species from wild seeded to seedless cultivars that may be diploid, triploid or tetraploid.

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Article Synopsis
  • Researchers studied sesame plants using a method called RAD-seq to see which technique, single-digest or double-digest, worked better for analyzing their DNA.
  • They found big differences in the genetic details between the sesame samples, which helped them identify the most diverse types of sesame in their study.
  • The study also gave suggestions on how to improve RAD-seq methods for analyzing larger groups of plants in future research.
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Cryopreservation approaches have been implemented in gene banks as a strategy to back up plant genetic resource collections that are vegetatively propagated. Different strategies have been employed to effectively cryopreserve plant tissue. There is little information on the cellular processes and molecular adjustments that confer resilience to the multiple stresses imposed during a cryoprotocol.

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Over the last decade, Cu-labeling of monoclonal antibody (mAb) via inverse electron demand Diels-Alder click chemistry (IEDDA) have received much attention. Despite the tetrazine-transcyclooctene (Tz-TCO) click chemistry's convenience and efficiency in mAb labeling, there is limited information about the ideal parameters in the development of click chemistry mediated (radio)immunoconjugates. This encourages us to conduct a systematic optimization while concurrently determining the physiochemical characteristics of the model mAb, trastuzumab, and TCO conjugates.

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Sesame, one of the ancient oil crops, is an important oilseed due to its nutritionally rich seeds with high protein content. Genomic scale information for sesame has become available in the public databases in recent years. The genes and their families involved in oil biosynthesis in sesame are less studied than in other oilseed crops.

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Triple-negative breast cancer (TNBC) does not express estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Because TNBC lacks the expression of commonly targeted receptors, it is challenging to develop a new imaging agent for this cancer subtype. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are RNA-protein complexes that have been linked to tumor development and progression.

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Purpose: Hydrogen sulfide (HS) plays important roles in brain pathophysiology. However, nuclear imaging probes for the in vivo detection of brain HS in living animals have not been developed. Here, we report the first nuclear imaging probe that enables in vivo imaging of endogenous HS in the brain of live mice.

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Carbon concentrating mechanisms (CCMs) in plants are abaptive features that have evolved to sustain plant growth in unfavorable environments, especially at low atmospheric carbon levels and high temperatures. Uptake of CO and its storage in the aerenchyma tissues of Lycopsids and diurnal acidity fluctuation in aquatic plants during the Palaeozoic era (ca. 300 Ma.

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Immuno-positron emission tomography (immuno-PET) is a rapidly growing imaging technique in which antibodies are radiolabeled to monitor their in vivo behavior in real time. However, effecting the controlled conjugation of a chelate-bearing radioactive atom to a bulky antibody without affecting its immunoreactivity at a specific site is always challenging. The in vivo stability of the radiolabeled chelate is also a key issue for successful tumor imaging.

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An efficient protocol for kinetic resolution of tertiary alcohols has been developed through an unprecedented asymmetric enamide-imine tautomerism process enabled by chiral phosphoric acid catalysis. A broad range of racemic 2-arylsulfonamido tertiary allyl alcohols could be kinetically resolved with excellent kinetic resolution performances (with s-factor up to >200). This method is particularly effective for a series of 1,1-dialkyl substituted allyl alcohols, which produced chiral tertiary alcohols that would be difficult to access via other asymmetric methods.

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Correction for 'A short PEG linker alters the in vivo pharmacokinetics of trastuzumab to yield high-contrast immuno-PET images' by Woonghee Lee et al., J. Mater.

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The prolonged blood circulation of the radiolabeled antibody conjugates is problematic when using immuno-PET imaging due to the increased radiation exposure and longer hospitalization required until sufficient contrast develops. In contrast to the prevailing belief that PEGylation prolongs blood retention time, we observed that a PEGylated antibody with a short PEG linker cleared much faster from the blood while maintaining tumor uptake compared to its non-PEGylated counterpart. Breast tumors were clearly visualized with a very high tumor-to-background ratio as early as 24 h after injection in immuno-positron emission tomography (PET) imaging.

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Chiral molecules with multiple stereocenters are widely present in natural products and pharmaceuticals, whose absolute and relative configurations are both critically important for their physiological activities. In spite of the fact that a series of ingenious strategies have been developed for asymmetric diastereodivergent catalysis, most of these methods are limited to the divergent construction of point chirality. Here we report an enantioselective and diastereodivergent synthesis of trisubstituted allenes by asymmetric additions of oxazolones to activated 1,3-enynes enabled by chiral phosphoric acid (CPA) catalysis, where the divergence of the allenic axial stereogenicity is realized by modifications of CPA catalysts.

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An efficient method for the asymmetric synthesis of 4H-3,1-benzoxazines was developed by kinetic resolution of 2-amido benzyl alcohols using chiral phosphoric acid catalyzed intramolecular cyclizations. A broad range of benzyl alcohols (both secondary and tertiary alcohols) were kinetically resolved with high selectivities, with an s factor of up to 94. Mechanistic studies were performed to elucidate the mechanism of these reactions, wherein the amide moieties reacted as the electrophiles.

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A highly enantioselective kinetic resolution of tertiary 2-alkoxycarboxamido allylic alcohols has been achieved through a chiral phosphoric acid catalyzed intramolecular transesterification reaction. Both alkyl,aryl- and dialkyl-substituted tertiary allylic alcohols were resolved with excellent efficiencies, affording both the recovered tertiary alcohols and the carbamate products with high enantioselectivities (with s factors up to 164.6).

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The asymmetric Friedel-Crafts alkylation reactions of indoles with β-substituted cyclopentenimines enabled by chiral phosphoric acid catalysis has been developed, which affords adducts possessing an all-carbon stereocenter with high levels of enantioselectivities. Furthermore, the addition products could be readily converted into two types of useful but previously challenging chiral building blocks, such as β-alkyl-β-indolyl cyclopentanones and β-alkyl-β-indolyl cyclopentylamides, in one pot via in situ hydrolysis or reduction without erosion of chiral information.

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The regioselective and enantioselective synthesis of β-indolyl cyclopentenamides, a versatile chiral building block, by asymmetric addition of indoles to α,β-unsaturated iminium intermediates has been achieved through chiral anion catalysis. Key to the success of this methodology is the generation of a chiral anion-paired ketone-type α,β-unsaturated iminium intermediate from α-hydroxy enamides. Preliminary mechanistic studies and DFT calculations are consistent with a mechanism involving multiple, concurrent pathways for isomerization of the initially formed azaallylcation into the key α,β-unsaturated iminium intermediate, all mediated by the phosphoric acid catalyst.

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Article Synopsis
  • Bipolaris sorghicola is a significant seed-borne pathogen affecting sorghum, and 32 strains were collected from various regions in India for study.
  • Molecular characterization utilized three different marker systems—URP, ISSR, and RAPD—to reveal geographic clustering and genetic variability among the strains.
  • The study found that the combined use of these three markers showed high cophenetic correlation, suggesting that this approach is effective for analyzing genetic diversity in B. sorghicola.
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Coarse grains are important group of crops that constitutes staple food for large population residing primarily in the arid and semi-arid regions of the world. Coarse grains are designated as nutri-cereals as they are rich in essential amino acids, minerals and vitamins. In spite of having several nutritional virtues in coarse grain as mentioned above, there is still scope for improvement in quality parameters such as cooking qualities, modulation of nutritional constituents and reduction or elimination of anti-nutritional factors.

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