Author
Todd A. Anderson
Other affiliations: Wildlife Conservation Society, University of Tennessee, Iowa State University ...read more
Bio: Todd A. Anderson is an academic researcher from Texas Tech University. The author has contributed to research in topics: Perchlorate & Loam. The author has an hindex of 56, co-authored 243 publications receiving 14624 citations. Previous affiliations of Todd A. Anderson include Wildlife Conservation Society & University of Tennessee.
Papers published on a yearly basis
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TL;DR: More than 50% of miRNA genes are located in cancer-associated genomic regions or in fragile sites, suggesting that miRNAs may play a more important role in the pathogenesis of a limited range of human cancers than previously thought.
2,299 citations
TL;DR: The results indicate that many miRNA families are evolutionarily conserved across all major lineages of plants, including mosses, gymnosperms, monocots and eudicots, and that miRNAs are conserved and little phylogenetic signal exists in the presence or absence of these mi RNAs.
Abstract: MicroRNA (miRNA) is one class of newly identified, small, non-coding RNAs that play versatile and important roles in post-transcriptional gene regulation. All miRNAs have similar secondary hairpin structures; many of these are evolutionarily conserved. This suggests a powerful approach to predict the existence of new miRNA orthologs or homologs in other species. We developed a comprehensive strategy to identify new miRNA homologs by mining the repository of available ESTs. A total of 481 miRNAs, belonging to 37 miRNA families in 71 different plant species, were identified from more than 6 million EST sequences in plants. The potential targets of the EST-predicted miRNAs were also elucidated from the EST and protein databases, providing additional evidence for the real existence of these miRNAs in the given plant species. Some plant miRNAs were physically clustered together, suggesting that these miRNAs have similar gene expression patterns and are transcribed together as a polycistron, as observed among animal miRNAs. The uracil nucleotide is dominant in the first position of 5' mature miRNAs. Our results indicate that many miRNA families are evolutionarily conserved across all major lineages of plants, including mosses, gymnosperms, monocots and eudicots. Additionally, the number of miRNAs discovered was directly related to the number of available ESTs and not to evolutionary relatedness to Arabidopsis thaliana, indicating that miRNAs are conserved and little phylogenetic signal exists in the presence or absence of these miRNAs. Regulation of gene expression by miRNAs appears to have existed at the earliest stages of plant evolution and has been tightly constrained (functionally) for more than 425 million years.
717 citations
TL;DR: Plant miRNAs are involved in plant development, signal transduction, protein degradation, response to environmental stress and pathogen invasion, and regulate their own biogenesis, and play important roles in plant post-transcriptional gene regulation.
677 citations
671 citations
TL;DR: It is revealed that miRNAs were significantly different from other RNAs (p < 0.001) and miRNA genes were less conserved than other RNA genes, although their mature miRNA sequences were highly conserved.
Abstract: An examination of 513 known pre-miRNAs and 237 other RNAs (tRNA, rRNA, and mRNA) revealed that miRNAs were significantly different from other RNAs (p < 0.001). miRNA genes were less conserved than other RNA genes, although their mature miRNA sequences were highly conserved. The A+U content of pre-miRNAs was higher than non-coding RNA (p < 0.001), but lower than mRNAs. The nucleotides in pre-miRNAs formed more hydrogen bonds and base pairs than in other RNAs. miRNAs had higher negative adjusted minimal folding free energies than other RNAs except tRNAs (p < 0.001). The MFE index (MFEI) was a sufficient criterion to distinguish miRNAs from all coding and non-coding RNAs (p < 0.001). The MFEI for miRNAs was 0.97, significantly higher than tRNAs (0.64), rRNAs (0.59), or mRNAs (0.65). Our findings should facilitate the prediction and identification of new miRNAs using computational and experimental strategies.
522 citations
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TL;DR: The current understanding of alterations in the epigenetic landscape that occur in cancer compared with normal cells, the roles of these changes in cancer initiation and progression, including the cancer stem cell model, and the potential use of this knowledge in designing more effective treatment strategies are discussed.
Abstract: Epigenetic mechanisms are essential for normal development and maintenance of tissue-specific gene expression patterns in mammals. Disruption of epigenetic processes can lead to altered gene function and malignant cellular transformation. Global changes in the epigenetic landscape are a hallmark of cancer. The initiation and progression of cancer, traditionally seen as a genetic disease, is now realized to involve epigenetic abnormalities along with genetic alterations. Recent advancements in the rapidly evolving field of cancer epigenetics have shown extensive reprogramming of every component of the epigenetic machinery in cancer including DNA methylation, histone modifications, nucleosome positioning and non-coding RNAs, specifically microRNA expression. The reversible nature of epigenetic aberrations has led to the emergence of the promising field of epigenetic therapy, which is already making progress with the recent FDA approval of three epigenetic drugs for cancer treatment. In this review, we discuss the current understanding of alterations in the epigenetic landscape that occur in cancer compared with normal cells, the roles of these changes in cancer initiation and progression, including the cancer stem cell model, and the potential use of this knowledge in designing more effective treatment strategies.
4,033 citations
TL;DR: Strong acids and bases seem to be the best desorbing agents to produce arsenic concentrates, and some commercial adsorbents which include resins, gels, silica, treated silica tested for arsenic removal come out to be superior.
3,168 citations
TL;DR: This Review summarizes the current knowledge of how these intriguing molecules are generated in animal cells.
Abstract: Small RNAs of 20-30 nucleotides can target both chromatin and transcripts, and thereby keep both the genome and the transcriptome under extensive surveillance. Recent progress in high-throughput sequencing has uncovered an astounding landscape of small RNAs in eukaryotic cells. Various small RNAs of distinctive characteristics have been found and can be classified into three classes based on their biogenesis mechanism and the type of Argonaute protein that they are associated with: microRNAs (miRNAs), endogenous small interfering RNAs (endo-siRNAs or esiRNAs) and Piwi-interacting RNAs (piRNAs). This Review summarizes our current knowledge of how these intriguing molecules are generated in animal cells.
3,081 citations
TL;DR: This review provides a summary of the recent occurrence of micropollutants in the aquatic environment including sewage, surface water, groundwater and drinking water.
2,933 citations
TL;DR: It is concluded that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses, and fundamental changes in chemical testing and safety determination are needed to protect human health.
Abstract: For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from...
2,475 citations