Publications by authors named "Srividya Ramakrishnan"

Modern maize (Zea mays ssp. mays) was domesticated from Teosinte parviglumis (Zea mays ssp. parviglumis), with subsequent introgressions from Teosinte mexicana (Zea mays ssp.

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An enduring question in evolutionary biology concerns the degree to which episodes of convergent trait evolution depend on the same genetic programs, particularly over long timescales. In this work, we genetically dissected repeated origins and losses of prickles-sharp epidermal projections-that convergently evolved in numerous plant lineages. Mutations in a cytokinin hormone biosynthetic gene caused at least 16 independent losses of prickles in eggplants and wild relatives in the genus .

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We present the genome of the living fossil, , a southern hemisphere conifer morphologically unchanged since the Cretaceous. Presumed extinct until rediscovery in 1994, the Wollemi pine is critically endangered with less than 60 wild adults threatened by intensifying bushfires in the Blue Mountains of Australia. The 12 Gb genome is among the most contiguous large plant genomes assembled, with extremely low heterozygosity and unusual abundance of DNA transposons.

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  • Carbapenem-resistant Enterobacterales (CRE) pose a significant public health threat, and understanding their spread in healthcare settings is crucial for containment.
  • The study collected and analyzed CRE isolates from The Johns Hopkins Medical Institutions between 2016 and 2018, identifying a small percentage as carbapenem-resistant and revealing genetic diversity among them.
  • Key findings indicate a high prevalence of KPC-producing CRE and specific plasmids that may aid in the spread of resistance genes, suggesting targeted interventions are needed to curb their transmission in healthcare environments.
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  • * A deep-learning model can predict allele-specific activity using only local nucleotide sequences, emphasizing key transcription-factor-binding motifs affected by genetic variants.
  • * Combining EN-TEx with previous genome annotations shows significant connections between allele-specific loci and GWAS loci, and aids in transferring known eQTLs to challenging tissue types, improving personal functional genomics research.
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The highly diverse Solanaceae family contains several widely studied models and crop species. Fully exploring, appreciating, and exploiting this diversity requires additional model systems. Particularly promising are orphan fruit crops in the genus Physalis, which occupy a key evolutionary position in the Solanaceae and capture understudied variation in traits such as inflorescence complexity, fruit ripening and metabolites, disease and insect resistance, self-compatibility, and most notable, the striking inflated calyx syndrome (ICS), an evolutionary novelty found across angiosperms where sepals grow exceptionally large to encapsulate fruits in a protective husk.

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In this paper, continuous crystallization of Atorvastatin calcium (ASC) using a continuous oscillatory baffled crystallizer (COBC) has been investigated. Like most API manufacturing, ASC is manufactured batchwise and the pure API is recovered via batch combined cooling and antisolvent crystallization (CCAC) process, which has the challenges of low productivity, wide crystal size distribution (CSD) and sometimes polymorphic form contamination. To overcome the limitations of the batch crystallization, continuous crystallization of ASC was studied in a NiTech (United Kingdom) DN15 COBC, manufactured by Alconbury Weston Ltd.

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There are many short-read variant-calling tools, with different strengths and weaknesses. We present a tool, Minos, which combines outputs from arbitrary variant callers, increasing recall without loss of precision. We benchmark on 62 samples from three bacterial species and an outbreak of 385 Mycobacterium tuberculosis samples.

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  • - Klebsiella pneumoniae (Kp) is a major cause of healthcare-related infections, leading to increased patient illness and healthcare costs, particularly linked to gut colonization where the infecting strain often originates.
  • - A study identified a specific tellurite-resistance (ter) operon that seems to have a crucial but not fully understood role in Kp infections, separate from other virulence factors and antibiotic resistance genes.
  • - Research using mouse models demonstrated that the ter operon boosts Kp's survival in the gut but is not essential during severe infections; its effect is influenced by the gut microbiota, particularly those that produce short-chain fatty acids.
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The early COVID-19 pandemic was characterized by rapid global spread. In Maryland and Washington, DC, United States, more than 2500 cases were reported within 3 weeks of the first COVID-19 detection in March 2020. We aimed to use genomic sequencing to understand the initial spread of SARS-CoV-2 - the virus that causes COVID-19 - in the region.

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  • Positive COVID-19 tests can occur even after negative results, and prolonged viral RNA shedding has been linked to infectiousness, particularly in symptomatic individuals.
  • A study using over 29,000 specimens found that virus growth in culture was more likely with lower cycle threshold (Ct) values, specifically a mean Ct of 18.8, indicating active infection.
  • Whole-genome sequencing confirmed that patients often carried the same virus over time, and high Ct values (greater than 29.5) were generally associated with non-infectious positivity.
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Background: The early COVID-19 pandemic has been characterized by rapid global spread. In the United States National Capital Region, over 2,000 cases were reported within three weeks of its first detection in March 2020. We aimed to use genomic sequencing to understand the initial spread of SARS-CoV-2, the virus that causes COVID-19, in the region.

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Structural variants (SVs) underlie important crop improvement and domestication traits. However, resolving the extent, diversity, and quantitative impact of SVs has been challenging. We used long-read nanopore sequencing to capture 238,490 SVs in 100 diverse tomato lines.

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We present RaGOO, a reference-guided contig ordering and orienting tool that leverages the speed and sensitivity of Minimap2 to accurately achieve chromosome-scale assemblies in minutes. After the pseudomolecules are constructed, RaGOO identifies structural variants, including those spanning sequencing gaps. We show that RaGOO accurately orders and orients 3 de novo tomato genome assemblies, including the widely used M82 reference cultivar.

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  • Researchers sequenced the genome of the pineapple variety Ananas comosus var. bracteatus CB5, revealing insights into its genetic structure with 29,412 identified genes across 25 chromosomes.
  • The study compared multiple pineapple genomes and revealed specific genetic traits related to fiber production, sugar accumulation, and fruit maturation, confirming varied domestication processes across cultivars.
  • The findings indicate a blend of sexual and asexual reproduction in the domestication of clonally propagated crops, encouraging further investigation into these processes for other similar species.
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Triboluminescence (TL) is shown to enable selective detection of trace crystallinity within nominally amorphous solid dispersions (ASDs). ASDs are increasingly used for the preparation of pharmaceutical formulations, the physical stability of which can be negatively impacted by trace crystallinity introduced during manufacturing or storage. In the present study, TL measurements of a model ASD consisting of griseofulvin in polyethylene glycol produced limits of detection of 140 ppm.

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Linked-Read sequencing technology has recently been employed successfully for assembly of human genomes, however, the utility of this technology for complex plant genomes is unproven. We evaluated the technology for this purpose by sequencing the 3.5-gigabase (Gb) diploid pepper () genome with a single Linked-Read library.

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Second harmonic generation (SHG) was integrated with Raman spectroscopy for the analysis of pharmaceutical materials. Particulate formulations of clopidogrel bisulfate were prepared in two crystal forms (Form I and Form II). Image analysis approaches enable automated identification of particles by bright field imaging, followed by classification by SHG.

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Background: Determining interacting SNPs in genome-wide association studies is computationally expensive yet of considerable interest in genomics.

Findings: We present a program Chi8 that calculates the Chi-square 8 degree of freedom test between all pairs of SNPs in a brute force manner on a Graphics Processing Unit. We analyze each of the seven WTCCC genome-wide association studies that have about 5000 total case and controls and 400,000 SNPs in an average of 9.

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