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Bhusal L, Amgain K, Dangal G, Tamang PD, Shahi P, Budhathoki P, Paudel AK. Virology, Clinical Features and Diagnosis of COVID 19: Review Analysis. Kathmandu Univ Med J (KUMJ) 2021; 18:75-79. [PMID: 33605243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
COVID-19 requires unprecedented mobilization of the health systems to prevent the rapid spread of this unique virus, which spreads via respiratory droplet and causes respiratory disease. There is an urgent need for an accurate and rapid test method to quickly identify many infected patients and asymptomatic carriers to prevent virus transmission and assure timely treatment of the patients. This article aims as an outcome of review of the evidence on viral load and its virulence of SARS-CoV2,so that it will help in further understanding the fact useful for investigating and managing the COVID-19 cases. A search of available evidence was conducted in pub-med "COVID-19 viral load and virulence" and its associated characters world-wide and Google Scholar to capture the most recently published articles. The WHO and Centre for Disease Control and Prevention (CDC) database of publications on novel coronavirus were also screened for relevant publications. Abstracts of 55 articles were screened by two authors and 15 were included in this study based on the inclusion criteria. SARS-coV2, the causative agent of COVID-19 falls under the coronavirus family but it has higher infectivity compared to SARS and MERS with higher reproduction numbers(Ro). Virulence has been found to be different throughout the world,however lower compared to SARS and MERS,till date. The most common clinical features have been found to be cough and fever. RT - PCR remains the most sensitive and specific method for the diagnosis of COVID-19 although it is time consuming, costly and requires highly skilled human resources. Hence, newer modalities like RT- LAMP can be alternative for point of care diagnosis as this is both cost effective and requires less skilled human resources. Despite recent advances in disease diagnosis and treatment outcomes using latest technological advances in molecular biology, the global pandemic COVID-19 remains a major headache for governments across the world due to limited testing capacity and lack of appropriate treatment and vaccine.
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Affiliation(s)
- L Bhusal
- Department of Emergency and General Practise, Shree Birendra Hospital, Kathmandu, Nepal
| | - K Amgain
- Department of Clinical Anatomy and Cell Biology, Karnali Academy of Health Sciences, Jumla, Nepal
| | - G Dangal
- Department of Obstetric and Gynecology, Kathmandu Model Hospital
| | | | - P Shahi
- Research and Development, Manavta, Nepal
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Su N, Qin BC, Zhu KJ, Liu ZY, Shahi P, Sun JP, Wang BS, Sui Y, Shi YG, Zhao LD, Cheng JG. Pressure-induced enhancement of thermoelectric power factor in pristine and hole-doped SnSe crystals. RSC Adv 2019; 9:26831-26837. [PMID: 35528554 PMCID: PMC9070544 DOI: 10.1039/c9ra05134a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 08/21/2019] [Indexed: 11/21/2022] Open
Abstract
We evaluate the influence of pressure on the thermoelectric power factors PF ≡ S2σ of pristine and Na-doped SnSe crystals by measuring their electrical conductivity σ(T) and Seebeck coefficient S(T) up to ∼22 kbar with a self-clamped piston-cylinder cell. For both cases, σ(T) is enhanced while S(T) reduced with increasing pressure as expected, but their imbalanced variations lead to a monotonic enhancement of PF under pressure. For pristine SnSe, σ(290 K) increases by ∼4 times from ∼10.1 to 38 S cm−1, while S(290 K) decreases by only ∼12% from 474 to 415 μV K−1, leading to about three-fold enhancement of PF from 2.24 to 6.61 μW cm−1 K−2, which is very close to the optimal value of SnSe above the structural transition at ∼800 K at ambient pressure. In comparison, the PF of Na-doped SnSe at 290 K is enhanced moderately by ∼30% up to 20 kbar. In contrast, the PF of isostructural black phosphorus with a simple band structure was found to decrease under pressure. The comparison with black phosphorus indicates that the multi-valley valence band structure of SnSe is beneficial for the enhancement of PF by retaining a large Seebeck coefficient under pressure. Our results also provide experimental confirmation on the previous theoretical prediction that high pressure can be used to optimize the thermoelectric efficiency of SnSe. The thermoelectric power factor of SnSe is enhanced by three times under a hydrostatic pressure of 22.5 kbar.![]()
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Singh R, Hansen T, Ritter C, Sharma N, Shahi P, Chatterjee S, Das A. Pressure induced effects on the chemical and magnetic structure of spinel MnV 2O 4. J Phys Condens Matter 2017; 29:345802. [PMID: 28657548 DOI: 10.1088/1361-648x/aa7c3e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The influence of external pressure (P ⩽ 5 GPa) on both the structural and magnetic ordering in MnV2O4 has been investigated using neutron diffraction technique. The volume and the V-V distance decrease with pressure while the c/a ratio increases, suggesting a lowering of the distortion with pressure. Under ambient conditions this compound exhibits a structural transition (T S) from tetragonal to cubic at ~53 K and a magnetic transition (T N ) at ~56 K. It is found that with an increase in pressure to 5 GPa, T N increases (from 56 K to 80 K), dT N /dP > 0, while T S decreases (from 53 K to 37 K). The non collinear magnetic structure in the tetragonal phase at 5 GPa and 10 K remains the same as at ambient pressure. However, the Mn and V sublattice, now exhibits distinct transition temperatures, [Formula: see text] ~ 80 K, and [Formula: see text] ~ 60 K. The transition to the cubic phase at T S is accompanied by a collinear alignment of the Mn and V spins and a reduction in the Mn moment. The region in which the structure remains in the cubic phase with collinear magnetic structure increases with pressure from ~3 K at ambient pressure to ~43 K at 5 GPa pressure.
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Affiliation(s)
- Ripandeep Singh
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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Shahi P, Wang CY, Chou J, Hagerling C, Gonzalez Velozo H, Ruderisch A, Yu Y, Lai MD, Werb Z. GATA3 targets semaphorin 3B in mammary epithelial cells to suppress breast cancer progression and metastasis. Oncogene 2017; 36:5567-5575. [PMID: 28581515 PMCID: PMC5629104 DOI: 10.1038/onc.2017.165] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 03/23/2017] [Accepted: 04/25/2017] [Indexed: 12/23/2022]
Abstract
Semaphorin 3B (SEMA3B) is a secreted axonal guidance molecule that is expressed during development and throughout adulthood. Recently, SEMA3B has emerged as a tumor suppressor in non-neuronal cells. Here we show that SEMA3B is a direct target of GATA3 transcriptional activity. GATA3 is a key transcription factor that regulates genes involved in mammary luminal cell differentiation and tumor suppression. We show that GATA3 relies on SEMA3B for suppression of tumor growth. Loss of SEMA3B renders GATA3 inactive and promotes aggressive breast cancer development. Overexpression of SEMA3B in cells lacking GATA3 induces a GATA3-like phenotype and higher levels of SEMA3B are associated with better cancer patient prognosis. Moreover, SEMA3B interferes with activation of LIM kinases (LIMK1 and LIMK2) to abrogate breast cancer progression. Our data provide new insights into the role of SEMA3B in mammary gland and provides a new branch of GATA3 signaling that is pivotal for inhibition of breast cancer progression and metastasis.
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Affiliation(s)
- P Shahi
- Department of Anatomy and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA.,Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - C-Y Wang
- Department of Anatomy and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA.,Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - J Chou
- Department of Anatomy and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - C Hagerling
- Department of Anatomy and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - H Gonzalez Velozo
- Department of Anatomy and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - A Ruderisch
- Department of Anatomy and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Y Yu
- Department of Anatomy and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - M-D Lai
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Z Werb
- Department of Anatomy and the Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
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Sun JP, Ye GZ, Shahi P, Yan JQ, Matsuura K, Kontani H, Zhang GM, Zhou Q, Sales BC, Shibauchi T, Uwatoko Y, Singh DJ, Cheng JG. High-T_{c} Superconductivity in FeSe at High Pressure: Dominant Hole Carriers and Enhanced Spin Fluctuations. Phys Rev Lett 2017; 118:147004. [PMID: 28430492 DOI: 10.1103/physrevlett.118.147004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Indexed: 06/07/2023]
Abstract
The importance of electron-hole interband interactions is widely acknowledged for iron-pnictide superconductors with high transition temperatures (T_{c}). However, the absence of hole pockets near the Fermi level of the iron-selenide (FeSe) derived high-T_{c} superconductors raises a fundamental question of whether iron pnictides and chalcogenides have different pairing mechanisms. Here, we study the properties of electronic structure in the high-T_{c} phase induced by pressure in bulk FeSe from magnetotransport measurements and first-principles calculations. With increasing pressure, the low-T_{c} superconducting phase transforms into the high-T_{c} phase, where we find the normal-state Hall resistivity changes sign from negative to positive, demonstrating dominant hole carriers in contrast to other FeSe-derived high-T_{c} systems. Moreover, the Hall coefficient is enlarged and the magnetoresistance exhibits anomalous scaling behaviors, evidencing strongly enhanced interband spin fluctuations in the high-T_{c} phase. These results in FeSe highlight similarities with high-T_{c} phases of iron pnictides, constituting a step toward a unified understanding of iron-based superconductivity.
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Affiliation(s)
- J P Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - G Z Ye
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Science and Astronomy, Yunnan University, Kunming 650091, China
| | - P Shahi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - J-Q Yan
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - K Matsuura
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - H Kontani
- Department of Physics, Nagoya University, Furo-cho, Nagoya 464-8602, Japan
| | - G M Zhang
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
| | - Q Zhou
- School of Physical Science and Astronomy, Yunnan University, Kunming 650091, China
| | - B C Sales
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Shibauchi
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
| | - Y Uwatoko
- The Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - D J Singh
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211-7010, USA
| | - J-G Cheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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Shukla KK, Shahi P, S. G, Kumar A, Ghosh AK, Singh R, Sharma N, Das A, Sinha AK, Joshi AG, Nigam AK, Chatterjee S. Magnetic and optical properties of Fe doped crednerite CuMnO2. RSC Adv 2015. [DOI: 10.1039/c5ra13305j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A geometrically frustrated magnetic CuMnO2 system has been investigated because of its rich magnetic properties.
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Affiliation(s)
- Kaushal K. Shukla
- Department of Physics
- Indian Institute of Technology (Banaras Hindu University)
- Varanasi-221005
- India
| | - P. Shahi
- Department of Physics
- Indian Institute of Technology (Banaras Hindu University)
- Varanasi-221005
- India
| | - Gopal S.
- School of Material Science & Technology
- Indian Institute of Technology, (Banaras Hindu University)
- Varanasi 221005
- India
| | - A. Kumar
- Department of Physics
- Indian Institute of Technology (Banaras Hindu University)
- Varanasi-221005
- India
| | - A. K. Ghosh
- Department of Physics
- Banaras Hindu University
- Varanasi 221005
- India
| | - Ripandeep Singh
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - Neetika Sharma
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - A. Das
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai 400085
- India
| | - A. K. Sinha
- Indus Synchrotrons Utilization Division
- Raja Ramanna Centre for Advanced Technology
- Indore 452013
- India
| | | | - A. K. Nigam
- Department of CMP & MS Tata Institute of Fundamental Research
- Mumbai
- India
| | - Sandip Chatterjee
- Department of Physics
- Indian Institute of Technology (Banaras Hindu University)
- Varanasi-221005
- India
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Srivastava PK, Küffer S, Brors B, Shahi P, Li L, Kenzelmann M, Gretz N, Gröne HJ. A cut-off based approach for gene expression analysis of formalin-fixed and paraffin-embedded tissue samples. Genomics 2008; 91:522-9. [PMID: 18490134 DOI: 10.1016/j.ygeno.2008.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 02/27/2008] [Accepted: 03/04/2008] [Indexed: 01/09/2023]
Abstract
Microarray analysis of formalin-fixed and paraffin-embedded (FFPE) tissue seems to be of importance for the detection of molecular marker sets in prostate cancer (PC). The compromised RNA integrity of FFPE tissue results in a high degree of variability at the probe level of microarray data as shown by degradation plot. We tested methods that reduce the variability by including all probes within 300 nucleotides, within 600 nucleotides, or up to a calculated breakpoint with reference to the 3'-end. Accepted PC pathways such as the Wnt signaling pathway could be observed to be significantly regulated within FFPE microarray datasets. The best representation of PC gene expression, as well as better comparability to meta-analysis and fresh-frozen microarray data, could be obtained with a 600-nucleotide cutoff. Beyond the specific impact for PC microarray data analysis we propose a cutoff of 600 nucleotides for samples for which the integrity of the RNA cannot be guaranteed.
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Affiliation(s)
- Prashant K Srivastava
- Department of Cellular and Molecular Pathology, German Cancer Research Center, D-69120 Heidelberg, Germany
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Pandey SP, Shahi P, Gase K, Baldwin IT. Herbivory-induced changes in the small-RNA transcriptome and phytohormone signaling in Nicotiana attenuata. Proc Natl Acad Sci U S A 2008; 105:4559-64. [PMID: 18339806 PMCID: PMC2290812 DOI: 10.1073/pnas.0711363105] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Indexed: 01/18/2023] Open
Abstract
Phytohormones mediate the perception of insect-specific signals and the elicitation of defenses during insect attack. Large-scale changes in a plant's transcriptome ensue, but how these changes are regulated remains unknown. Silencing of RNA-directed RNA polymerase 1 (RdR1) makes Nicotiana attenuata highly susceptible to insect herbivores, suggesting that defense elicitation is under the direct control of small-RNAs (smRNAs). Using 454-sequencing, we characterized N. attenuata's smRNA transcriptome before and after insect-specific elicitation in wild-type (WT) and RdR1-silenced (irRdR1) plants. We predicted the targets of N. attenuata smRNAs in the genes related to phytohormone signaling (jasmonic acid, JA-Ile, and ethylene) known to mediate resistance responses, and we measured the elicited dynamics of phytohormone biosynthetic transcripts and phytohormone levels in time-course experiments with field- and glasshouse-grown plants. RdR1 silencing severely altered the induced transcript accumulation of 8 of the 10 genes, reduced JA, and enhanced ethylene levels after elicitation. Adding JA completely restored the insect resistance of irRdR1 plants. irRdR1 plants had photosynthetic rates, growth, and reproductive output indistinguishable from that of WT plants, suggesting unaltered primary metabolism. We conclude that the susceptibility of irRdR1 plants to herbivores is due to altered phytohormone signaling and that smRNAs play a central role in coordinating the large-scale transcriptional changes that occur after herbivore attack. Given the diversity of smRNAs that are elicited after insect attack and the recent demonstration of the ability of ingested smRNAs to silence transcript accumulation in lepidopteran larvae midguts, the smRNA responses of plants may also function as direct defenses.
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Affiliation(s)
- Shree P. Pandey
- *Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745 Jena, Germany; and
| | - Priyanka Shahi
- Medical Research Center, University Hospital Mannheim, 68167 Mannheim, Germany
| | - Klaus Gase
- *Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745 Jena, Germany; and
| | - Ian T. Baldwin
- *Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745 Jena, Germany; and
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Pandey SP, Sharma S, Chand R, Shahi P, Joshi AK. Clonal Variability and Its Relevance in Generation of New Pathotypes in the Spot Blotch Pathogen, Bipolaris sorokiniana. Curr Microbiol 2007; 56:33-41. [PMID: 17909887 DOI: 10.1007/s00284-007-9034-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Spot blotch pathogen Bipolaris sorokiniana of wheat was investigated with threefold objectives: to establish a relationship between morphological and pathological variability of isolates, identify clonal genotype(s) acting as a source for the generation of new variability, and to determine the mechanism of generation of such variability in the pathogen. Isolates were collected from the leaves and seeds of field-grown wheat crop at four different sites in eastern Gangetic plains of India. Eighty-six clonal isolates derived from a single isolate (gray with white patches, Group III), which segregated in an equal proportion of parental and nonparental types, were studied. Morphological characters-i.e., colony morphology, growth rate, and sporulation-were studied along with disease-causing ability of the isolate clones. Clonal isolates were grouped into three categories. Microscopic analysis of nuclei was done to determine the causes of such variability. Morphological variability appeared to be related to the pathological variability. The isolate having epidemic potential appeared different than that acting as the reservoir for variability. The cause of such variability could be attributed either to hyphal fusion and heterokaryosis, nuclear migration and occurrence of multinucleate state, or a combination of these factors. Random Amplified Polymorphic DNA (RAPD) assay suggested that the unique fragments for different groups could be utilized as molecular markers to identify the isolates of specific groups.
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Affiliation(s)
- Shree P Pandey
- Department of Genetics and Plant Breeding, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221 005, India
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Shahi P, Loukianiouk S, Bohne-Lang A, Kenzelmann M, Küffer S, Maertens S, Eils R, Gröne HJ, Gretz N, Brors B. Argonaute--a database for gene regulation by mammalian microRNAs. Nucleic Acids Res 2006; 34:D115-8. [PMID: 16381827 PMCID: PMC1347455 DOI: 10.1093/nar/gkj093] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
MicroRNAs (miRNAs) constitute a recently discovered class of small non-coding RNAs that regulate expression of target genes either by decreasing the stability of the target mRNA or by translational inhibition. They are involved in diverse processes, including cellular differentiation, proliferation and apoptosis. Recent evidence also suggests their importance for cancerogenesis. By far the most important model systems in cancer research are mammalian organisms. Thus, we decided to compile comprehensive information on mammalian miRNAs, their origin and regulated target genes in an exhaustive, curated database called Argonaute (). Argonaute collects latest information from both literature and other databases. In contrast to current databases on miRNAs like miRBase::Sequences, NONCODE or RNAdb, Argonaute hosts additional information on the origin of an miRNA, i.e. in which host gene it is encoded, its expression in different tissues and its known or proposed function, its potential target genes including Gene Ontology annotation, as well as miRNA families and proteins known to be involved in miRNA processing. Additionally, target genes are linked to an information retrieval system that provides comprehensive information from sequence databases and a simultaneous search of MEDLINE with all synonyms of a given gene. The web interface allows the user to get information for a single or multiple miRNAs, either selected or uploaded through a text file. Argonaute currently has information on 839 miRNAs from human, mouse and rat.
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Affiliation(s)
- Priyanka Shahi
- Medical Research Center, University Hospital MannheimD-68167 Mannheim, Germany
- Department of Cellular and Molecular Pathology, German Cancer Research CenterD-69120 Heidelberg, Germany
- Department of Theoretical Bioinformatics, German Cancer Research CenterIm Neuenheimer Feld 580, D-69120 Heidelberg, Germany
| | - Serguei Loukianiouk
- Medical Research Center, University Hospital MannheimD-68167 Mannheim, Germany
| | - Andreas Bohne-Lang
- Medical Research Center, University Hospital MannheimD-68167 Mannheim, Germany
| | - Marc Kenzelmann
- Department of Cellular and Molecular Pathology, German Cancer Research CenterD-69120 Heidelberg, Germany
| | - Stefan Küffer
- Department of Cellular and Molecular Pathology, German Cancer Research CenterD-69120 Heidelberg, Germany
| | - Sabine Maertens
- Department of Cellular and Molecular Pathology, German Cancer Research CenterD-69120 Heidelberg, Germany
| | - Roland Eils
- Department of Theoretical Bioinformatics, German Cancer Research CenterIm Neuenheimer Feld 580, D-69120 Heidelberg, Germany
| | - Herrmann-Josef Gröne
- Department of Cellular and Molecular Pathology, German Cancer Research CenterD-69120 Heidelberg, Germany
| | - Norbert Gretz
- Medical Research Center, University Hospital MannheimD-68167 Mannheim, Germany
| | - Benedikt Brors
- Department of Theoretical Bioinformatics, German Cancer Research CenterIm Neuenheimer Feld 580, D-69120 Heidelberg, Germany
- To whom correspondence should be addressed. Tel: +49 6221 42 3614; Fax: +49 6221 42 3620;
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Abstract
We screened for transposon-generated mutants of Synechocystis sp. strain PCC 6803 that exhibited aberrant phototactic movement. Of the 300 mutants generated, about 50 have been partially characterized; several contained transposons in genes encoding chemotaxis-related proteins, while others mapped to novel genes. These novel genes and their possible roles in motility are discussed.
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Affiliation(s)
- D Bhaya
- Department of Plant Biology, Carnegie Institution, Stanford, California 94305, USA.
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Bourbouloux A, Shahi P, Chakladar A, Delrot S, Bachhawat AK. Hgt1p, a high affinity glutathione transporter from the yeast Saccharomyces cerevisiae. J Biol Chem 2000; 275:13259-65. [PMID: 10788431 DOI: 10.1074/jbc.275.18.13259] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A high affinity glutathione transporter has been identified, cloned, and characterized from the yeast Saccharomyces cerevisiae. This transporter, Hgt1p, represents the first high affinity glutathione transporter to be described from any system so far. The strategy for the identification involved investigating candidate glutathione transporters from the yeast genome sequence project followed by genetic and physiological investigations. This approach revealed HGT1 (open reading frame YJL212c) as encoding a high affinity glutathione transporter. Yeast strains deleted in HGT1 did not show any detectable plasma membrane glutathione transport, and hgt1Delta disruptants were non-viable in a glutathione biosynthetic mutant (gsh1Delta) background. The glutathione repressible transport activity observed in wild type cells was also absent in the hgt1Delta strains. The transporter was cloned and kinetic studies indicated that Hgt1p had a high affinity for glutathione (K(m) = 54 micrometer)) and was not sensitive to competition by amino acids, dipeptides, or other tripeptides. Significant inhibition was observed, however, with oxidized glutathione and glutathione conjugates. The transporter reveals a novel class of transporters that has homologues in other yeasts and plants but with no apparent homologues in either Escherichia coli or in higher eukaryotes other than plants.
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Affiliation(s)
- A Bourbouloux
- ESA CNRS 6161, Laboratoire de Physiologie et Biochimie Végétales, University of Poitiers, UFR Sciences, 40 Avenue du Recteur Pineau, 86022 Poitiers Cédex, France
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