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result(s) for
"Mahadevan, Padmanabhan"
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CoreGenes5.0: An Updated User-Friendly Webserver for the Determination of Core Genes from Sets of Viral and Bacterial Genomes
2022
The determination of core genes in viral and bacterial genomes is crucial for a better understanding of their relatedness and for their classification. CoreGenes5.0 is an updated user-friendly web-based software tool for the identification of core genes in and data mining of viral and bacterial genomes. This tool has been useful in the resolution of several issues arising in the taxonomic analysis of bacteriophages and has incorporated many suggestions from researchers in that community. The webserver displays result in a format that is easy to understand and allows for automated batch processing, without the need for any user-installed bioinformatics software. CoreGenes5.0 uses group protein clustering of genomes with one of three algorithm options to output a table of core genes from the input genomes. Previously annotated “unknown genes” may be identified with homologues in the output. The updated version of CoreGenes is able to handle more genomes, is faster, and is more robust, providing easier analysis of custom or proprietary datasets. CoreGenes5.0 is accessible at coregenes.org, migrating from a previous site.
Journal Article
Classification of Myoviridae bacteriophages using protein sequence similarity
by
Summer, Elizabeth J
,
Kropinski, Andrew M
,
Mahadevan, Padmanabhan
in
Amino acid sequence
,
Bacteriophages
,
Biological Microscopy
2009
Background
We advocate unifying classical and genomic classification of bacteriophages by integration of proteomic data and physicochemical parameters. Our previous application of this approach to the entirely sequenced members of the
Podoviridae
fully supported the current phage classification of the International Committee on Taxonomy of Viruses (ICTV). It appears that horizontal gene transfer generally does not totally obliterate evolutionary relationships between phages.
Results
CoreGenes/CoreExtractor proteome comparison techniques applied to 102
Myoviridae
suggest the establishment of three subfamilies (
Peduovirinae
,
Teequatrovirinae
, the
Spounavirinae
) and eight new independent genera (Bcep781, BcepMu, FelixO1, HAP1, Bzx1, PB1, phiCD119, and phiKZ-like viruses). The
Peduovirinae
subfamily, derived from the P2-related phages, is composed of two distinct genera: the \"P2-like viruses\", and the \"HP1-like viruses\". At present, the more complex
Teequatrovirinae
subfamily has two genera, the \"T4-like\" and \"KVP40-like viruses\". In the genus \"T4-like viruses\" proper, four groups sharing >70% proteins are distinguished: T4-type, 44RR-type, RB43-type, and RB49-type viruses. The
Spounavirinae
contain the \"SPO1-\"and \"Twort-like viruses.\"
Conclusion
The hierarchical clustering of these groupings provide biologically significant subdivisions, which are consistent with our previous analysis of the
Podoviridae
.
Journal Article
From Orphan Phage to a Proposed New Family–The Diversity of N4-Like Viruses
by
Millard, Andrew D.
,
Kropinski, Andrew M.
,
Turner, Dann
in
Bacteria
,
bacterial viruses
,
Bacteriophages
2020
Escherichia phage N4 was isolated in 1966 in Italy and has remained a genomic orphan for a long time. It encodes an extremely large virion-associated RNA polymerase unique for bacterial viruses that became characteristic for this group. In recent years, due to new and relatively inexpensive sequencing techniques the number of publicly available phage genome sequences expanded rapidly. This revealed new members of the N4-like phage group, from 33 members in 2015 to 115 N4-like viruses in 2020. Using new technologies and methods for classification, the Bacterial and Archaeal Viruses Subcommittee of the International Committee on Taxonomy of Viruses (ICTV) has moved the classification and taxonomy of bacterial viruses from mere morphological approaches to genomic and proteomic methods. The analysis of 115 N4-like genomes resulted in a huge reassessment of this group and the proposal of a new family “Schitoviridae”, including eight subfamilies and numerous new genera.
Journal Article
Bacterial diversity in the clarki ecotype of the photosynthetic sacoglossan, Elysia crispata
2020
Few studies have examined the bacterial communities associated with photosynthetic sacoglossan sea slugs. In this study, we determined the bacterial diversity in the clarki ecotype, Elysia crispata using 16S rRNA sequencing. Computational analysis using QIIME2 revealed variability between individual samples, with the Spirochaetes and Bacteroidetes phyla dominating most samples. Tenericutes and Proteobacteria were also found, among other phyla. Computational metabolic profiling of the bacteria revealed a variety of metabolic pathways involving carbohydrate metabolism, lipid metabolism, nucleotide metabolism, and amino acid metabolism. Although associated bacteria may be involved in mutually beneficial metabolic pathways, there was a high degree of variation in the bacterial community of individual slugs. This suggests that many of these relationships are likely opportunistic rather than obligate and that many of these bacteria may live commensally providing no major benefit to the slugs. The bacterial diversity of the solar‐powered sea slug, Elysia crispata (clarki ecotype), was investigated. The results showed inter‐individual variability in bacterial diversity, suggesting that the bacteria live commensally with these sea slugs.
Journal Article
Evidence for a Retroviral Insertion in TRPM1 as the Cause of Congenital Stationary Night Blindness and Leopard Complex Spotting in the Horse
by
Bellone, Rebecca R.
,
Pruvost, Melanie
,
Hofreiter, Michael
in
Adenylation
,
Animal sciences
,
Animals
2013
Leopard complex spotting is a group of white spotting patterns in horses caused by an incompletely dominant gene (LP) where homozygotes (LP/LP) are also affected with congenital stationary night blindness. Previous studies implicated Transient Receptor Potential Cation Channel, Subfamily M, Member 1 (TRPM1) as the best candidate gene for both CSNB and LP. RNA-Seq data pinpointed a 1378 bp insertion in intron 1 of TRPM1 as the potential cause. This insertion, a long terminal repeat (LTR) of an endogenous retrovirus, was completely associated with LP, testing 511 horses (χ(2)=1022.00, p<<0.0005), and CSNB, testing 43 horses (χ(2)=43, p<<0.0005). The LTR was shown to disrupt TRPM1 transcription by premature poly-adenylation. Furthermore, while deleterious transposable element insertions should be quickly selected against the identification of this insertion in three ancient DNA samples suggests it has been maintained in the horse gene pool for at least 17,000 years. This study represents the first description of an LTR insertion being associated with both a pigmentation phenotype and an eye disorder.
Journal Article
Spectral tuning and deactivation kinetics of marine mammal melanopsins
by
Mahadevan, Padmanabhan
,
Algrain, Haya
,
Schweikert, Lorian E.
in
Amino Acid Sequence
,
Amino acids
,
Analysis
2021
In mammals, the photopigment melanopsin (Opn4) is found in a subset of retinal ganglion cells that serve light detection for circadian photoentrainment and pupil constriction (i.e., mydriasis). For a given species, the efficiency of photoentrainment and length of time that mydriasis occurs is determined by the spectral sensitivity and deactivation kinetics of melanopsin, respectively, and to date, neither of these properties have been described in marine mammals. Previous work has indicated that the absorbance maxima (λ max ) of marine mammal rhodopsins (Rh1) have diversified to match the available light spectra at foraging depths. However, similar to the melanopsin λ max of terrestrial mammals (~480 nm), the melanopsins of marine mammals may be conserved, with λ max values tuned to the spectrum of solar irradiance at the water’s surface. Here, we investigated the Opn4 pigments of 17 marine mammal species inhabiting diverse photic environments including the Infraorder Cetacea, as well as the Orders Sirenia and Carnivora. Both genomic and cDNA sequences were used to deduce amino acid sequences to identify substitutions most likely involved in spectral tuning and deactivation kinetics of the Opn4 pigments. Our results show that there appears to be no amino acid substitutions in marine mammal Opn4 opsins that would result in any significant change in λ max values relative to their terrestrial counterparts. We also found some marine mammal species to lack several phosphorylation sites in the carboxyl terminal domain of their Opn4 pigments that result in significantly slower deactivation kinetics, and thus longer mydriasis, compared to terrestrial controls. This finding was restricted to cetacean species previously found to lack cone photoreceptor opsins, a condition known as rod monochromacy. These results suggest that the rod monochromat whales rely on extended pupillary constriction to prevent photobleaching of the highly photosensitive all-rod retina when moving between photopic and scotopic conditions.
Journal Article
Nutritional assessment, phytochemical composition and antioxidant analysis of the pulp and seed of medjool date grown in Mexico
by
Rosas-González, Navor
,
Mahadevan, Padmanabhan
,
Haro-Vázquez, María del Pilar
in
Agricultural Science
,
Analysis
,
Antioxidant activities
2019
The aim of this study was the characterization of fatty acids, antioxidant activity, some physical properties, nutrient content, sugars, and minerals in the pulp and seeds of the date cultivar ‘Medjool’ ( Phoenix dactylifera L.) grown in Mexico. The samples were obtained at maturity (Tamar) in the 2017 harvest season in the valleys of San Luis Rio Colorado and Mexicali, Mexico. The following average values were obtained on a % dry weight basis for pulp and seeds, respectively: protein, 3.14% and 4.84%; lipids, 0.75% and 9.94%; fiber, 6.34% and 66.79%; total sugars, 75.32% and 5.88%; reducing sugars, 70.26% and 4.40%; and sucrose, 5.06% and 1.46%. Analysis of the minerals revealed that the most abundant elements for the pulp were: potassium, 851.98 mg/100 g; magnesium, 142.97 mg/100 g; and phosphorus, 139.40 mg/100 g, whereas for the seeds, they were potassium, 413.36 mg/100 g; sulfur, 151.36 mg/100 g; and phosphorus, 92.42 mg/100 g. Gas chromatography-mass spectrometry analysis revealed that the major unsaturated fatty acid was oleic acid, at 52.34% and 45.92%, respectively, for pulp and seeds. The main saturated fatty acids were palmitic acid (6.75%) and lauric acid (17.24%) in pulp and seeds, respectively. The total phenolic content was 1.16 and 13.73 mg GAE/100 g for pulp and seeds, respectively. Finally, the antioxidant activities were: b-carotene, 65.50% and 47.75%; DPPH, 0.079 IC 50 g/L and 0.0046 IC 50 g/L; and ABTS, 13.72 IC 50 g/L and 0.238 IC 50 g/L, respectively. The results obtained in this study confirm that the ‘Medjool’ cultivar grown in Mexico has the same quality of nutrients and antioxidants as those grown in the other main date-producing countries.
Journal Article
CGUG: in silico proteome and genome parsing tool for the determination of \core\ and unique genes in the analysis of genomes up to ca. 1.9 Mb
by
Mahadevan, Padmanabhan
,
Seto, Donald
,
King, John F
in
Biomedical and Life Sciences
,
Biomedicine
,
Life Sciences
2009
Background
Viruses and small-genome bacteria (~2 megabases and smaller) comprise a considerable population in the biosphere and are of interest to many researchers. These genomes are now sequenced at an unprecedented rate and require complementary computational tools to analyze. \"CoreGenesUniqueGenes\" (CGUG) is an
in silico
genome data mining tool that determines a \"core\" set of genes from two to five organisms with genomes in this size range. Core and unique genes may reflect similar niches and needs, and may be used in classifying organisms.
Findings
CGUG is available at
http://binf.gmu.edu/geneorder.html
as a web-based on-the-fly tool that performs iterative BLASTP analyses using a reference genome and up to four query genomes to provide a table of genes common to these genomes. The result is an
in silico
display of genomes and their proteomes, allowing for further analysis. CGUG can be used for \"genome annotation by homology\", as demonstrated with
Chlamydophila
and
Francisella
genomes.
Conclusion
CGUG is used to reanalyze the ICTV-based classifications of bacteriophages, to reconfirm long-standing relationships and to explore new classifications. These genomes have been problematic in the past, due largely to horizontal gene transfers. CGUG is validated as a tool for reannotating small genome bacteria using more up-to-date annotations by similarity or homology. These serve as an entry point for wet-bench experiments to confirm the functions of these \"hypothetical\" and \"unknown\" proteins.
Journal Article
Genome-Wide SNP Signal Intensity Scanning Revealed Genes Differentiating Cows with Ovarian Pathologies from Healthy Cows
by
Villa-Angulo, Carlos
,
Ortiz-Uribe, Noé
,
Salomón-Torres, Ricardo
in
Axiom Genome-Wide Bos 1 array
,
bioinformatics
,
Genomes
2017
Hypoplasia and ovarian cysts are the most common ovarian pathologies in cattle. In this genome-wide study we analyzed the signal intensity of 648,315 Single Nucleotide Polymorphisms (SNPs) and identified 1338 genes differentiating cows with ovarian pathologies from healthy cows. The sample consisted of six cows presenting an ovarian pathology and six healthy cows. SNP signal intensities were measured with a genotyping process using the Axiom Genome-Wide BOS 1 SNPchip. Statistical tests for equality of variance and mean were applied to SNP intensities, and significance p-values were obtained. A Benjamini-Hochberg multiple testing correction reveled significant SNPs. Corresponding genes were identified using the Bovine Genome UMD 3.1 annotation. Principal Components Analysis (PCA) confirmed differentiation. An analysis of Copy Number Variations (CNVs), obtained from signal intensities, revealed no evidence of association between ovarian pathologies and CNVs. In addition, a haplotype frequency analysis showed no association with ovarian pathologies. Results show that SNP signal intensity, which captures not only information for base-pair genotypes elucidation, but the amount of fluorescence nucleotide synthetization produced in an enzymatic reaction, is a rich source of information that, by itself or in combination with base-pair genotypes, might be used to implement differentiation, prediction and diagnostic procedures, increasing the scope of applications for Genotyping Microarrays.
Journal Article
Rapid pair-wise synteny analysis of large bacterial genomes using web-based GeneOrder4.0
by
Mahadevan, Padmanabhan
,
Seto, Donald
in
Bacterial genetics
,
Biomedical and Life Sciences
,
Biomedicine
2010
Background
The growing whole genome sequence databases necessitate the development of user-friendly software tools to mine these data. Web-based tools are particularly useful to wet-bench biologists as they enable platform-independent analysis of sequence data, without having to perform complex programming tasks and software compiling.
Findings
GeneOrder4.0 is a web-based \"on-the-fly\" synteny and gene order analysis tool for comparative bacterial genomics (
ca
. 8 Mb). It enables the visualization of synteny by plotting protein similarity scores between two genomes and it also provides visual annotation of \"hypothetical\" proteins from older archived genomes based on more recent annotations.
Conclusions
The web-based software tool GeneOrder4.0 is a user-friendly application that has been updated to allow the rapid analysis of synteny and gene order in large bacterial genomes. It is developed with the wet-bench researcher in mind.
Journal Article