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Processing of rare earth concentrates

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Rare Metals 2005年第3期24卷 210-215页

作者： pamela Alex R.c. Hubli A.K. Suri Material Processing Division Bhabha Atomic Research Centre Trombay Mumbai-400085 IndiaMaterial Processing Division Bhabha Atomic Research Centre Trombay Mumbai-400085 IndiaMaterial Processing Division Bhabha Atomic Research Centre Trombay Mumbai-400085 India

The paper describes process details for extraction of rare earths from an intermediate grade concentrate of Madhya Pradesh region in India and a South African slag. The xenodme concentrate obtained from the former place was an intermediate grade （47%） rare earth phosphate containing both monazite and xenotime. The South African slag was a low-grade waste product typically containing only 4% of rare earths. The rare earth resource concentrates have been treated individually by different methods such as alkali fusion and alkali leaching to convert them into their mixed oxides. Both types of materials have been processed and greater than 98% solubilization of metal values has been achieved in the intermediate grade xenotime and 80% from the South African slag. The residue of xenotime hydroxide has been washed thoroughly to collect the sodium phosphate, as by-product and the slurry pH have been adjusted to separate rare earths from thorium effectively. Other impurities such as uranium and iron have been removed by precipitation of rare earths by oxalic acid. It has been possible to recover 〉95% yttrium along with other rare earth oxides.

关键词： xenotime slag fusion leaching calcining solubilization

Forecasting the impacts of chemical pollution and climate change interactions on the health of wildlife

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current Zoology 2015年第4期61卷 669-689页

作者： pamela D. NOYES Sean c. LEMA Department of Environmental & Molecular Toxicology Environmental Health Sciences Center Sinnhuber Aquatic ResearchLaboratory Oregon State University Corvallis OR USA Biological Sciences Department Center for Coastal Marine Sciences California Polytechnic State University San Luis Obispo CA 93407 USA

Global climate change is impacting organisms, biological communities and ecosystems around the world. While most research has focused on characterizing how the climate is changing, including modeling future climatic conditions and predicting the impacts of these conditions on biodiversity, it is also the case that climate change is altering the environmental impacts of chemical pollution. Future climate conditions are expected to influence both the worldwide distribution of chemicals and the toxi- cological consequences of chemical exposures to organisms. Many of the environmental changes associated with a warming global climate （e.g., increased average - and possibly extreme - temperatures; intense periods of drier and wetter conditions; reduced ocean pH; altered salinity dynamics in estuaries） have the potential to enhance organism susceptibility to chemical toxicity. Addi- tionally, chemical exposures themselves may impair the ability of organisms to cope with the changing environmental conditions of the shifting climate. Such reciprocity in the interactions between climate change and chemicals illustrates the complexity inherent in predicting the toxicological consequences of chemical exposures under future climate scenarios. Here, we summarize what is currently known about the potential reciprocal effects of climate change and chemical toxicity on wildlife, and depict current approaches and ongoing challenges for incorporating climate effects into chemical testing and assessment. Given the rapid pace of new man-made chemistries, the development of accurate and rapid methods to evaluate multiple chemical and non-chemical stressors in an ecologically relevant context will be critical to understanding toxic and endocrine-disrupting effects of chemical pollutants under future climate scenarios [current Zoology 61 （4）： 669-689, 2015].

关键词： Global wanning Toxicology Metals Endocrine disruptors Risk assessment

Strong Suppression of Systemic Acquired Resistance in Arabidopsis by NRR is Dependent on its Ability to Interact with NPRland its Putative Repression Domain

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Molecular Plant 2008年第3期1卷 552-559页

作者： Mawsheng chern Patrick E. canlas pamela c. Ronald Department of Plant Pathology University of California Davis CA 95616 USA

Systemic Acquired Resistance （SAR） in plants confers lasting broad-spectrum resistance to pathogens and requires the phytohormone salicylic acid （SA）. Arabidopsis NPR1/NIM1 is a key regulator of the SAR response. Studies attempting to reveal the function of NPR1 and how it mediates SA signaling have led to isolation of two classes of proteins that interact with NPRI＂ the first class includes rice NRR, Arabidopsis NIMIN1, NIMIN2, and NIMIN3, and tobacco NIMIN2-1ike proteins; the second class belongs to TGA transcription factors. We have previously shown that overexpression of N RR in rice suppresses both basal and Xa21-mediated resistance. In order to test whether NRR affects SA-induced, NPRl-mediated SAR, we have transformed Arabidopsis with the rice NRR gene and tested its effects on the defense response. Expression of NRR in Arabidopsis results in suppression of PR gene induction by SAR inducer and resistance to pathogens. These phenotypes are even more severe than those of the nprl-1 mutant. The ability of NRR to suppress PR gene induction and disease resistance is correlated with its ability to bind to NPR1 because two point mutations in NRR, which reduce NPR1 binding, fail to suppress NPR1. In contrast, wild-type and a mutant NRR, which still binds to NPR1 strongly, retain the ability to suppress the SAR response. Replacing the c-terminal 79 amino acids of NRR with the VP16 activation domain turns the fusion protein into a transcriptional co-activator. These results indicate that NRR binds to NPR1 in vivo in a protein complex to inhibit transcriptional activation of PR genes and that NRR contains a transcription repression domain for active repression.

关键词： NRR NPR1 SA SAR disease resistance.

construction of a Rice Glycosyltransferase Phylogenomic Database and Identification of Rice-Diverged Glycosyltransferases

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Molecular Plant 2008年第5期1卷 858-877页

作者： Pei-Jian cao Laura E. Bartley Ki-Hong Jung pamela c. Ronald Department of Plant Pathology University of California Davis CA 95616 and the Joint BioEnergy Institute Emeryville CA 94710 USA Institute of Bioinformatics Zhejiang University Hangzhou Zhejiang 310029 China

Glycosyltransferases （GTs; Ec 2.4.x.y） constitute a large group of enzymes that form glycosidic bonds through transfer of sugars from activated donor molecules to acceptor molecules. GTs are critical to the biosynthesis of plant cell walls, among other diverse functions. Based on the carbohydrate-Active enZymes （cAZy） database and sequence ***, we have identified 609 potential GT genes （loci） corresponding to 769 transcripts （gene models） in rice （Oryza sativa）, the reference monocotyledonous species. Using domain composition and sequence similarity, these rice GTs were classified into 40 cAZy families plus an additional unknown class. We found that two Pfam domains of unknown function, PF04577 and PF04646, are associated with GT families GT61 and GT31, respectively. To facilitate functional analysis of this important and large gene family, we created a phylogenomic Rice GT Database （http：//ricephylogenomics. ***/cellwalls/gtJ）. Through the database, several classes of functional genomic data, including mutant lines and gene expression data, can be displayed for each rice GT in the context of a phylogenetic tree, allowing for comparative analysis both within and between GT families. comprehensive digital expression analysis of public gene expression data revealed that most （-80%） rice GTs are expressed. Based on analysis with Inparanoid, we identified 282 ‘rice-diverged＇ GTs that lack orthologs in sequenced dicots （Arabidopsis thaliana, Populus tricocarpa, Medicago truncatula, and Ricinus communis）. combining these analyses, we identified 33 rice-diverged GT genes （45 gene models） that are highly expressed in above-ground, vegetative tissues. From the literature and this analysis, 21 of these loci are excellent targets for functional examination toward understanding and manipulating grass cell wall qualities. Study of the remainder may reveal aspects of hormone and protein metabolism that are critical for rice biology. This list of 33 genes a

关键词： glycosyltransferases GT phylogenetic tree orthologs expression pattern mutant lines phylogenomic database rice cell wall.

Recent Advances in Dissecting Stress-Regulatory crosstalk in Rice

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Molecular Plant 2013年第2期6卷 250-260页

作者： Rita Sharma David De Vleesschauwer Manoj K. Sharma pamela c. Ronald Department of Plant Pathology and Genome center University of California Davis CA 95616 USA Joint BioEnergy Institute Emeryville CA 94710 USA Laboratory of Phytopathology Faculty of Bioscience Engineering Ghent University B-9000 Ghent Belgium Department of Plant Molecular Systems Biotechnology and crop Biotech Institute Kyung Hee University Yongin 446-701 Korea

Biotic and abiotic stresses impose a serious limitation on crop productivity worldwide. Prior or simultaneous exposure to one type of stress often affects the plant response to other stresses, indicating extensive overlap and cross-talk between stress-response signaling pathways. Systems biology approaches that integrate large genomic and prot-eomic data sets have facilitated identification of candidate genes that govern this stress-regulatory crosstalk. Recently, we constructed a yeast two-hybrid map around three rice proteins that control the response to biotic and abiotic stresses, namely the immune receptor XA21, which confers resistance to the Gram-negative bacterium, Xanthomonas oryzae pv. oryzae; NH1, the rice ortholog of NPR1, a key regulator of systemic acquired resistance; and the ethylene-responsive transcription factor, SUBIA, which confers tolerance to submergence stress. These studies coupled with transcriptional profiling and co-expression analyses identified a suite of proteins that are positioned at the interface of biotic and abiotic stress responses, including mitogen-activated protein kinase 5 （OsMPK5）, wall-associated kinase 25 （WAK25）, sucrose non-fermenting-l-related protein kinase-1 （SnRK1）, SUBIA binding protein 23 （SAB23）, and several WRKY family tran- scription factors. Emerging evidence suggests that these genes orchestrate crosstalk between biotic and abiotic stresses through a variety of mechanisms, including regulation of cellular energy homeostasis and modification of synergistic and/or antagonistic interactions between the stress hormones salicylic acid, ethylene, jasmonic acid, and abscisic acid.

关键词： abiotic biotic crosstalk defense response hormone systems biology stress.

Heating Up the Environmental context of chemical Pollution： Ecotoxicology in a changing Global climate

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current Zoology 2015年第4期61卷 614-616页

作者： pamela D. NOYES Sean c. LEMA Guest Editors Department of Environmental & Molecular Toxicology Sinnhuber Aquatic Research Laboratory Oregon State University Corvallis OR USA Biological Sciences Department Center for Coastal Marine Sciences California Polytechnic State University San Luis Obispo CA USA

Humans and wildlife are exposed to an ever-increasing array of man-made chemicals that are now meas-ured in every habitat on our planet from the Earth＇s highest mountain peaks to sediments in the deep ocean （e.g., Farrington and Takada, 2014; Quiroz et al., 2009; Veron et al., 1987; Villa et al., 2006）. In addition to the expanding variety of synthetic chemistries in use, there are many substances that are components of the Earth that may through human activities concentrate at high- levels or be released into the environment in forms that enhance their bioavailability, exposure, and toxicity potential.

关键词：光环境生态毒理学全球气候化学污染加热化学物质人类活动生物利用度

Rice Protein Tagging Project:A call for International collaborations on Genome-wide In-Locus Tagging of Rice Proteins

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Molecular Plant 2020年第12期13卷 1663-1665页

作者： Yuming Lu pamela c.Ronald Bin Han Jiayang Li Jian-Kang Zhu Shanghai center for Plant Stress Biology CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina Department of Plant Pathology and the Genome center University of CaliforniaDavisCAUSA National center for Gene Research CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghaiChina State Key Laboratory of Plant Genomics and National Center for Plant Gene Research(Beijing)Institute of Genetics and Developmental BiologyInnovation Academy for Seed DesignChinese Academy of SciencesBeijingChina Department of Horticulture and Landscape Architecture Purdue UniversityWest LafayetteINUSA

In September 1997,the International Rice Genome Sequencing Project was *** initiative pooled the resources of ten nations to obtain the first complete rice genome sequence,and promoted rice research and breeding into the post-genomics era(Li et al.,2018).In 2008,an internationally coordinated project named "RIcE2020" was proposed to systematically and fully characterize all rice genes,transcripts,and proteins(Zhang et al.,2008).While genes and their transcripts can be readily characterized by sequencing-and PcR-based methods,the characterization of protein dynamics including protein levels,subcellular localizations,post-transla-tional modifications,and interactions with macromolecules(e.g.,proteins,DNA,RNA,carbohydrates,and lipids)and small molecules(e.g.,metabolites and ligands)is much more challenging and usually requires antibodies that specifically recognize the protein of *** it is very difficult to systematically produce reliable antibodies for the specific recognition of individual plant proteins,a common practice is to transform a tag-fused open reading frame(ORF)of a gene to the corresponding loss-of-function mutant ***,such an ectopically expressed tagged protein may not fully reca-pitulate the properties of the endogenous protein due to the random insertion of the transgene,even when the transgene is expressed under the endogenous gene promoter.A preferred so-lution is to genetically label the coding sequence of the gene of interest,at its in vivo locus,with a sequence encoding a fluores-cent protein tag or an affinity tag such as FLAG or *** "in-locus" protein tagging,as we are naming it here,has been carried out genome-wide in yeast,caenorhabditis elegans,fly,and mammalian cultured cells,greatly facilitating the characterization of proteins in these organisms(Jiang et al.,2018).In 2017,a Genome Tagging Project was launched in mice,aiming to label every protein using a cRISPR/cas9-based "artificial spermatids"method(

关键词： breeding Genome endogenous

Alcohol-induced protein hyperacetylation: Mechanisms and consequences

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World Journal of Gastroenterology 2009年第10期15卷 1219-1230页

作者： Blythe D Shepard pamela L Tuma Department of Biology The Catholic University of America 620 Michigan Avenue NE Washington DC 20064 United States

Although the clinical manifestations of alcoholic liver disease are well-described, little is known about the molecular basis of liver injury. Recent studies have indicated that ethanol exposure induces global protein hyperacetylationo This reversible, post- translational modification on the E-amino groups of lysine residues has been shown to modulate multiple, diverse cellular processes ranging from transcriptional activation to microtubule stability. Thus, alcohol- induced protein hyperacetylation likely leads to major physiological consequences that contribute to alcohol-induced hepatotoxicity. Lysine acetylation is controlled by the activities of two opposing enzymes, histone acetyltransferases and histone deacetylases. currently, efforts are aimed at determining which enzymes are responsible for the increased acetylation of specific substrates. However, the greater challenge will be to determine the physiological ramifications of protein hyperacetylation and how they might contribute to the progression of liver disease. In this review, we will first list and discuss the proteins known to be hyperacetylated in the presence of ethanol. We will then describe what is known about the mechanisms leading to increased protein acetylation and how hyperacetylation may perturb hepatic function.

关键词： Ethanol Hepatotoxicity Acetylation Deacetylases Acetyltransferases

SFRP4 expression correlates with epithelial mesenchymal transitionlinked genes and poor overall survival in colon cancer patients

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World Journal of Gastrointestinal Oncology 2019年第8期11卷 589-598页

作者： Landry E Nfonsam Jana Jandova Hunter c Jecius pamela N Omesiete Valentine N Nfonsam Department of Genetics Children’s Hospital of Eastern OntarioOttawaOntario K1H 8L1Canada Department of Surgery University of ArizonaTucsonAZ 85724United States

BAcKGROUND colon cancer is among the most commonly diagnosed cancers in the United States with an estimated 97220 new cases expected by the end of *** affects 1.2 million people around the world and is responsible for about 0.6 million deaths every *** decline in overall incidence and mortality over the past 30 years,there continues to be an alarming rise in early-onset colon cancer cases(creted frizzled-related protein 4(SFRP4),is over-expressed in early-onset colon ***4 is speculated to play an essential role in cancer by inhibiting the epithelial mesenchymal transition(EMT).AIM To investigate the correlation between SFRP4 expression and EMT-linked genes in colon cancer and how it affects patient *** SFRP4 expression relative to that of EMT-linked genes and survival analysis were performed using the University of california Santa cruz cancer Browser *** SFRP4 was found to be co-expressed with the EMT-linked markers cDH2,FN1,VIM,TWIST1,TWIST2,SNAI1,SNAI2,ZEB1,ZEB2,POSTN,MMP2,MMP7,MMP9,and ***4 expression negatively correlated with the EMTlinked suppressors cLDN4,cLDN7,TJP3,MUc1,and *** expression of SFRP4 and the EMT-linked markers was higher in mesenchymal-like samples compared to epithelial-like samples which potentially implicates SFRP4-EMT mechanism in colon ***,patients overexpressing SFRP4 presented with poor overall survival(P=0.0293).cONcLUSION considering the implication of SFRP4 in early-onset colon cancer,particularly in the context of EMT,tumor metastasis,and invasion,and the effect of increased expression on colon cancer patient survival,SFRP4 might be a potential biomarker for early-onset colon cancer that could be targeted for diagnosis and/or disease therapy.

关键词： Secreted frizzled-related protein 4 Epithelial mesenchymal transition colon cancer Survival