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Sample records for type abc transporter

  1. ABC transporter genes and risk of type 2 diabetes

    DEFF Research Database (Denmark)

    Schou, Jesper; Tybjærg-Hansen, Anne; Møller, Holger Jon

    2012-01-01

    Alterations of pancreatic β-cell cholesterol content may contribute to β-cell dysfunction. Two important determinants of intracellular cholesterol content are the ATP-binding cassette (ABC) transporters A1 (ABCA1) and -G1 (ABCG1). Whether genetic variation in ABCA1 and ABCG1 predicts risk of type 2...... diabetes in the general population is unknown....

  2. Structural and mechanistic insights into ABC-type ECF transporters for vitamin uptake

    NARCIS (Netherlands)

    Dosz-Majsnerowska, Maria

    2014-01-01

    Dit proefschrift gaat over de relatie tussen de structuur en het mechanisme van ABC-type ECF transporters voor vitamines, uit de bacterie Lactococcus lactis. Energy-Coupling Factor (ECF) transporters vormen een subgroep van de ATP-binding cassette (ABC) transporters en zijn betrokken bij de opname

  3. Thermodynamics of ABC transporters

    Directory of Open Access Journals (Sweden)

    Xuejun C. Zhang

    2015-09-01

    Full Text Available ABSTRACT ABC transporters form the largest of all transporter families, and their structural study has made tremendous progress over recent years. However, despite such advances, the precise mechanisms that determine the energy-coupling between ATP hydrolysis and the conformational changes following substrate binding remain to be elucidated. Here, we present our thermodynamic analysis for both ABC importers and exporters, and introduce the two new concepts of differential-binding energy and elastic conformational energy into the discussion. We hope that the structural analysis of ABC transporters will henceforth take thermodynamic aspects of transport mechanisms into account as well.

  4. Energy Coupling Efficiency in the Type I ABC Transporter GlnPQ.

    Science.gov (United States)

    Lycklama A Nijeholt, Jelger A; Vietrov, Ruslan; Schuurman-Wolters, Gea K; Poolman, Bert

    2018-03-16

    Solute transport via ATP binding cassette (ABC) importers involves receptor-mediated substrate binding, which is followed by ATP-driven translocation of the substrate across the membrane. How these steps are exactly initiated and coupled, and how much ATP it takes to complete a full transport cycle, are subject of debate. Here, we reconstitute the ABC importer GlnPQ in nanodiscs and in proteoliposomes and determine substrate-(in)dependent ATP hydrolysis and transmembrane transport. We determined the conformational states of the substrate-binding domains (SBDs) by single-molecule Förster resonance energy transfer measurements. We find that the basal ATPase activity (ATP hydrolysis in the absence of substrate) is mainly caused by the docking of the closed-unliganded state of the SBDs onto the transporter domain of GlnPQ and that, unlike glutamine, arginine binds both SBDs but does not trigger their closing. Furthermore, comparison of the ATPase activity in nanodiscs with glutamine transport in proteoliposomes shows that the stoichiometry of ATP per substrate is close to two. These findings help understand the mechanism of transport and the energy coupling efficiency in ABC transporters with covalently linked SBDs, which may aid our understanding of Type I ABC importers in general. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. The predicted ABC transporter AbcEDCBA is required for type IV secretion system expression and lysosomal evasion by Brucella ovis.

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    Teane M A Silva

    Full Text Available Brucella ovis is a major cause of reproductive failure in rams and it is one of the few well-described Brucella species that is not zoonotic. Previous work showed that a B. ovis mutant lacking a species-specific ABC transporterabcBA was attenuated in mice and was unable to survive in macrophages. The aim of this study was to evaluate the role of this ABC transporter during intracellular survival of B. ovis. In HeLa cells, B. ovis WT was able to survive and replicate at later time point (48 hpi, whereas an ΔabcBA mutant was attenuated at 24 hpi. The reduced survival of the ΔabcBA mutant was associated with a decreased ability to exclude the lysosomal marker LAMP1 from its vacuolar membrane, suggesting a failure to establish a replicative niche. The ΔabcBA mutant showed a reduced abundance of the Type IV secretion system (T4SS proteins VirB8 and VirB11 in both rich and acid media, when compared to WT B. ovis. However, mRNA levels of virB1, virB8, hutC, and vjbR were similar in both strains. These results support the notion that the ABC transporter encoded by abcEDCBA or its transported substrate acts at a post-transcriptional level to promote the optimal expression of the B. ovis T4SS within infected host cells.

  6. The role of ABCG-type ABC transporters in phytohormone transport.

    Science.gov (United States)

    Borghi, Lorenzo; Kang, Joohyun; Ko, Donghwi; Lee, Youngsook; Martinoia, Enrico

    2015-10-01

    Plant hormones (phytohormones) integrate endogenous and exogenous signals thus synchronizing plant growth with environmental and developmental changes. Similar to animals, phytohormones have distinct source and target tissues, hence controlled transport and focused targeting are required for their functions. Many evidences accumulated in the last years about the regulation of long-distance and directional transport of phytohormones. ATP-binding cassette (ABC) transporters turned out to play major roles in routing phytohormones not only in the plant body but also towards the outer environment. The ABCG-type proteins ABCG25 and ABCG40 are high affinity abscisic acid (ABA) transporters. ABCG14 is highly co-expressed with cytokinin biosynthesis and is the major root-to-shoot cytokinin transporter. Pleiotropic drug resistance1 (PDR1) from Petunia hybrida transports strigolactones (SLs) from the root tip to the plant shoot but also outside to the rhizosphere, where SLs are the main attractants to mycorrhizal fungi. Last but not least, ABCG36 and ABCG37 possibly play a dual role in coumarine and IBA transport. © 2015 Authors.

  7. ABC transporters in adaptive immunity.

    Science.gov (United States)

    Seyffer, Fabian; Tampé, Robert

    2015-03-01

    ABC transporters ubiquitously found in all kingdoms of life move a broad range of solutes across membranes. Crystal structures of four distinct types of ABC transport systems have been solved, shedding light on different conformational states within the transport process. Briefly, ATP-dependent flipping between inward- and outward-facing conformations allows directional transport of various solutes. The heterodimeric transporter associated with antigen processing TAP1/2 (ABCB2/3) is a crucial element of the adaptive immune system. The ABC transport complex shuttles proteasomal degradation products into the endoplasmic reticulum. These antigenic peptides are loaded onto major histocompatibility complex class I molecules and presented on the cell surface. We detail the functional modules of TAP, its ATPase and transport cycle, and its interaction with and modulation by other cellular components. In particular, we emphasize how viral factors inhibit TAP activity and thereby prevent detection of the infected host cell by cytotoxic T-cells. Merging functional details on TAP with structural insights from related ABC transporters refines the understanding of solute transport. Although human ABC transporters are extremely diverse, they still may employ conceptually related transport mechanisms. Appropriately, we delineate a working model of the transport cycle and how viral factors arrest TAP in distinct conformations. Deciphering the transport cycle of human ABC proteins is the major issue in the field. The defined peptidic substrate, various inhibitory viral factors, and its role in adaptive immunity provide unique tools for the investigation of TAP, making it an ideal model system for ABC transporters in general. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Evidence for an ABC-Type Riboflavin Transporter System in Pathogenic Spirochetes

    Science.gov (United States)

    Deka, Ranjit K.; Brautigam, Chad A.; Biddy, Brent A.; Liu, Wei Z.; Norgard, Michael V.

    2013-01-01

    ABSTRACT Bacterial transporter proteins are involved in the translocation of many essential nutrients and metabolites. However, many of these key bacterial transport systems remain to be identified, including those involved in the transport of riboflavin (vitamin B2). Pathogenic spirochetes lack riboflavin biosynthetic pathways, implying reliance on obtaining riboflavin from their hosts. Using structural and functional characterizations of possible ligand-binding components, we have identified an ABC-type riboflavin transport system within pathogenic spirochetes. The putative lipoprotein ligand-binding components of these systems from three different spirochetes were cloned, hyperexpressed in Escherichia coli, and purified to homogeneity. Solutions of all three of the purified recombinant proteins were bright yellow. UV-visible spectra demonstrated that these proteins were likely flavoproteins; electrospray ionization mass spectrometry and thin-layer chromatography confirmed that they contained riboflavin. A 1.3-Å crystal structure of the protein (TP0298) encoded by Treponema pallidum, the syphilis spirochete, demonstrated that the protein’s fold is similar to the ligand-binding components of ABC-type transporters. The structure also revealed other salient details of the riboflavin binding site. Comparative bioinformatics analyses of spirochetal genomes, coupled with experimental validation, facilitated the discovery of this new ABC-type riboflavin transport system(s). We denote the ligand-binding component as riboflavin uptake transporter A (RfuA). Taken together, it appears that pathogenic spirochetes have evolved an ABC-type transport system (RfuABCD) for survival in their host environments, particularly that of the human host. PMID:23404400

  9. Energy Coupling Factor-Type ABC Transporters for Vitamin Uptake in Prokaryotes

    NARCIS (Netherlands)

    Erkens, Guus B.; Dosz-Majsnerowska, Maria; ter Beek, Josy; Slotboom, Dirk Jan

    2012-01-01

    Energy coupling factor (ECF) transporters are a subgroup of ATP-binding cassette (ABC) transporters involved in the uptake of vitamins and micronutrients in prokaryotes. In contrast to classical ABC importers, ECF transporters do not make use of water-soluble substrate binding proteins or domains

  10. Plant ABC Transporters

    Science.gov (United States)

    Kang, Joohyun; Park, Jiyoung; Choi, Hyunju; Burla, Bo; Kretzschmar, Tobias; Lee, Youngsook; Martinoia, Enrico

    2011-01-01

    ABC transporters constitute one of the largest protein families found in all living organisms. ABC transporters are driven by ATP hydrolysis and can act as exporters as well as importers. The plant genome encodes for more than 100 ABC transporters, largely exceeding that of other organisms. In Arabidopsis, only 22 out of 130 have been functionally analyzed. They are localized in most membranes of a plant cell such as the plasma membrane, the tonoplast, chloroplasts, mitochondria and peroxisomes and fulfill a multitude of functions. Originally identified as transporters involved in detoxification processes, they have later been shown to be required for organ growth, plant nutrition, plant development, response to abiotic stresses, pathogen resistance and the interaction of the plant with its environment. To fulfill these roles they exhibit different substrate specifies by e.g. depositing surface lipids, accumulating phytate in seeds, and transporting the phytohormones auxin and abscisic acid. The aim of this review is to give an insight into the functions of plant ABC transporters and to show their importance for plant development and survival. PMID:22303277

  11. Structural diversity of ABC transporters

    Science.gov (United States)

    ter Beek, Josy; Guskov, Albert

    2014-01-01

    ATP-binding cassette (ABC) transporters form a large superfamily of ATP-dependent protein complexes that mediate transport of a vast array of substrates across membranes. The 14 currently available structures of ABC transporters have greatly advanced insight into the transport mechanism and revealed a tremendous structural diversity. Whereas the domains that hydrolyze ATP are structurally related in all ABC transporters, the membrane-embedded domains, where the substrates are translocated, adopt four different unrelated folds. Here, we review the structural characteristics of ABC transporters and discuss the implications of this structural diversity for mechanistic diversity. PMID:24638992

  12. The ABC transporters in Candidatus Liberibacter asiaticus

    Science.gov (United States)

    Li, Wenlin; Cong, Qian; Pei, Jimin; Kinch, Lisa N; Grishin, Nick V

    2012-01-01

    Candidatus Liberibacter asiaticus (Ca. L. asiaticus) is a Gram-negative bacterium and the pathogen of Citrus Greening disease (Huanglongbing, HLB). As a parasitic bacterium, Ca. L. asiaticus harbors ABC transporters that play important roles in exchanging chemical compounds between Ca. L. asiaticus and its host. Here, we analyzed all the ABC transporter-related proteins in Ca. L. asiaticus. We identified 14 ABC transporter systems and predicted their structures and substrate specificities. In-depth sequence and structure analysis including multiple sequence alignment, phylogenetic tree reconstruction, and structure comparison further support their function predictions. Our study shows that this bacterium could use these ABC transporters to import metabolites (amino acids and phosphates) and enzyme cofactors (choline, thiamine, iron, manganese, and zinc), resist to organic solvent, heavy metal, and lipid-like drugs, maintain the composition of the outer membrane (OM), and secrete virulence factors. Although the features of most ABC systems could be deduced from the abundant experimental data on their orthologs, we reported several novel observations within ABC system proteins. Moreover, we identified seven nontransport ABC systems that are likely involved in virulence gene expression regulation, transposon excision regulation, and DNA repair. Our analysis reveals several candidates for further studies to understand and control the disease, including the type I virulence factor secretion system and its substrate that are likely related to Ca. L. asiaticus pathogenicity and the ABC transporter systems responsible for bacterial OM biosynthesis that are good drug targets. PMID:22807026

  13. ABCdb: an ABC transporter database.

    Science.gov (United States)

    Quentin, Y; Fichant, G

    2000-10-01

    We present the first release of a database devoted to the ATP-binding cassette (ABC) protein domains (ABCdb). The ABC proteins are involved in a wide variety of physiological processes in Archea, Bacteria and Eucaryota where they are encoded by large families of paralogous genes. The majority of ABC domains energize the transport of compounds across the membranes. In bacteria, ABC transporters are involved in the uptake of a wide range of molecules and in mechanisms of virulence and antibiotic resistance. In eukaryotes, most of them are involved in drug resistance and in human cells, many are associated with diseases. Sequence analysis reveals that members of the ABC superfamily can be organized into sub-families and suggests that they have diverged from common ancestral forms. In this release, ABCdb includes the inventory and assembly of the ABC transporter systems of completely sequenced genomes. In addition to the protein entries, the database comprises information on functional domains, sequence motifs, predicted trans-membrane segments, and signal peptides. It also includes a classification in sub-families of the ABC systems as well as a classification of the different partners of the systems. Evolutionary trees and specific sequence patterns are provided for each sub-family. The database is endowed with a powerful query system and it was interfaced with blastP2 program for similarity searches. ABCdb has been developed in the ACeDB format, a database system developed by Jean Thierry-Mieg and Richard Durbin. ABCdb can be accessed via the World Wide Web (http://ir2lcb.cnrs-mrs.fr/ABCdb/).

  14. The ABC of ECF transporters : discovery and initial characterization of ECF-type ATP-binding casette (ABC) importers

    NARCIS (Netherlands)

    ter Beek, Josy

    2012-01-01

    Josy ter Beek heeft een nieuwe klasse transporteiwitten in de celmembraan ontdekt en gekarakteriseerd. Aangezien deze transporter alleen door bacteriën wordt gebruikt en voor het transport van verscheidene belangrijke stoffen zorgt, kan informatie over deze nieuwe klasse transporters in de toekomst

  15. The peroxisomal ABC transporter family

    NARCIS (Netherlands)

    Wanders, Ronald J. A.; Visser, Wouter F.; van Roermund, Carlo W. T.; Kemp, Stephan; Waterham, Hans R.

    2007-01-01

    This review describes the current state of knowledge about the ABCD family of peroxisomal half adenosine-triphosphate-binding cassette (ABC) transporters. ABCDs are predicted to be present in a variety of eukaryotic organisms, although at present, only ABCDs in the yeast Saccharomyces cerevisiae,

  16. ABC transporters in the CNS - an inventory.

    Science.gov (United States)

    Hartz, A M S; Bauer, B

    2011-04-01

    In the present review we provide a summary of ATP-binding cassette (ABC) transporters in the central nervous system (CNS). Our review is focused on transporters of the ABC A, B, C, D, and G families that have been detected in the cells of the neurovascular unit/blood-brain barrier including brain capillary endothelial cells, pericytes, astrocytes, and neurons, as well as in other brain cells, such as microglia, oligodendrocytes, and choroid plexus epithelial cells. In this review, we provide an overview, organized by ABC family, of transporter expression, localization, and function. We summarize recent findings on ABC transporter regulation in the CNS and address the role of ABC transporters in CNS diseases including brain cancer, seizures/epilepsy, and Alzheimer's disease. Finally, we discuss new therapeutic strategies focused on ABC transporters in CNS disease.

  17. Bioinformatic survey of ABC transporters in dermatophytes.

    Science.gov (United States)

    Gadzalski, Marek; Ciesielska, Anita; Stączek, Paweł

    2016-01-15

    ATP binding cassette (ABC) transporters constitute a very large and ubiquitous superfamily of membrane proteins. They are responsible for ATP hydrolysis driven translocation of countless substrates. Being a very old and diverse group of proteins present in all organisms they share a common feature, which is the presence of an evolutionary conservative nucleotide binding domain (NBD)--the engine that drives the transport. Another common domain is a transmembrane domain (TMD) which consists of several membrane-spanning helices. This part of protein is substrate-specific, thus it is much more variable. ABC transporters are known for driving drug efflux in many pathogens and cancer cells, therefore they are the subject of extensive studies. There are many examples of conferring a drug resistance phenotype in fungal pathogens by ABC transporters, however, little is known about these proteins in dermatophytes--a group of fungi causing superficial mycoses. So far only a single ABC transporter has been extensively studied in this group of pathogens. We analyzed available genomic sequences of seven dermatophyte species in order to provide an insight into dermatophyte ABC protein inventory. Phylogenetic studies of ABC transporter genes and their products were conducted and included ABC transporters of other fungi. Our results show that each dermatophyte genome studied possesses a great variety of ABC transporter genes. Detailed analysis of selected genes and their products indicates that relatively recent duplication of ABC transporter genes could lead to novel substrate specificity. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. An ABC-Type Cobalt Transport System Is Essential for Growth of Sinorhizobium melilotiat Trace Metal Concentrations ▿ †

    Science.gov (United States)

    Cheng, Jiujun; Poduska, Branislava; Morton, Richard A.; Finan, Turlough M.

    2011-01-01

    We report expression and mutant phenotypes for a gene cluster in Sinorhizobium meliloti, designated cbtJKL, that has been shown to encode an ABC-type cobalt transport system. Transcription of cbtJKLinitiated 384 nucleotides upstream from the cbtJtranslation start codon, and the resulting 5′ region contained a putative B12riboswitch. Expression of the cbtJKLgenes appeared to be controlled by (cobalt-loaded) cobalamin interacting at the B12riboswitch, since (i) a putative B12riboswitch was located within this large upstream region, (ii) cbtJtranscription was repressed upon addition of cobalt or vitamin B12, and (iii) deletions in the B12riboswitch resulted in constitutive cbtJKLtranscription. Insertion mutants in cbtJKLfailed to grow in LB medium, and growth was restored through the addition of cobalt but not other metals. This growth phenotype appeared to be due to the chelation of cobalt present in LB, and cbtJKLmutants also failed to grow in minimal medium containing the chelating agent EDTA unless the medium was supplemented with additional or excess cobalt. In uptake experiments, 57Co2+accumulation was high in wild-type cells expressing the cbtJKLgenes, whereas wild-type cells in which cbtJKLexpression was repressed showed reduced accumulation. In cbtJKLmutant cells, 57Co2+accumulation was reduced relative to that of the wild type, and presumably, this residual cobalt transport occurred via an alternate ion uptake system(s) that is not specific to cobalt. In symbiosis, the alternate system(s) appeared to mediate cobalt transport into bacteroid cells, as low cbtJKLexpression was detected in bacteroids and cbtJKLmutants formed N2-fixing nodules on alfalfa. PMID:21725018

  19. ABC transporters in megakaryopoiesis and platelet activity.

    Science.gov (United States)

    Wang, Wei; Buitrago, Lorena; Wang, Ying

    2017-08-01

    ATP-binding cassette (ABC) is a family of transporters that facilitates the translocation of substrates across cell membrane using its ATPase subunit. These transporters have key roles in multidrug resistance, lipid homeostasis, antigen processing, immunity, cell proliferation and hematopoiesis. Some ABC transporters are selectively expressed on megakaryocyte progenitor, megakaryocyte and its cellular fragment platelet. However, the role of ABC transporters in hemostasis and thrombosis were not well explored until recently. Studies of both human genetic diseases and genetically-manipulated animal models have greatly improved our understanding of ABC transporters in regulating hematopoiesis particularly megakaryopoiesis and/or platelet activity. Human genome wide association studies (GWAS) have also unraveled the association between ABC transporters and thrombopoiesis in general population. Therefore, this review aims to summarize the recent advances in our understanding of how ABC transporters regulate megakaryopoiesis and platelet activity, the underlining mechanisms and their association with atherosclerosis and atherothrombosis. Last, the emerging therapeutic targets to slow down atherosclerosis development and prevent atherothrombosis via ABC transporters or downstream pathways will also be discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The abcEDCBA-Encoded ABC Transporter and the virB Operon-Encoded Type IV Secretion System of Brucella ovis Are Critical for Intracellular Trafficking and Survival in Ovine Monocyte-Derived Macrophages.

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    Auricelio A Macedo

    Full Text Available Brucella ovis infection is associated with epididymitis, orchitis and infertility in rams. Most of the information available on B. ovis and host cell interaction has been generated using murine macrophages or epithelial cell lines, but the interaction between B. ovis and primary ovine macrophages has not been studied. The aim of this study was to evaluate the role of the B. ovis abcEDCBA-encoded ABC transporter and the virB operon-encoded Type IV Secretion System (T4SS during intracellular survival of B. ovis in ovine peripheral blood monocyte-derived macrophages. ΔabcBA and ΔvirB2 mutant strains were unable to survive in the intracellular environment when compared to the WT B. ovis at 48 hours post infection (hpi. In addition, these mutant strains cannot exclude the lysosomal marker LAMP1 from its vacuolar membrane, and their vacuoles do not acquire the endoplasmic reticulum marker calreticulin, which takes place in the WT B. ovis containing vacuole. Higher levels of nitric oxide production were observed in macrophages infected with WT B. ovis at 48 hpi when compared to macrophages infected with the ΔabcBA or ΔvirB2 mutant strains. Conversely, higher levels of reactive oxygen species were detected in macrophages infected with the ΔabcBA or ΔvirB2 mutant strains at 48 hpi when compared to macrophages infected with the WT strain. Our results demonstrate that B. ovis is able to persist and multiply in ovine macrophages, while ΔabcBA and ΔvirB2 mutations prevent intracellular multiplication, favor phagolysosome fusion, and impair maturation of the B. ovis vacuole towards an endoplasmic reticulum-derived compartment.

  1. Structural basis for the mechanism of ABC transporters.

    Science.gov (United States)

    Beis, Konstantinos

    2015-10-01

    The ATP-binding cassette (ABC) transporters are primary transporters that couple the energy stored in adenosine triphosphate (ATP) to the movement of molecules across the membrane. ABC transporters can be divided into exporters and importers; importers mediate the uptake of essential nutrients into cells and are found predominantly in prokaryotes whereas exporters transport molecules out of cells or into organelles and are found in all organisms. ABC exporters have been linked with multi-drug resistance in both bacterial and eukaryotic cells. ABC transporters are powered by the hydrolysis of ATP and transport their substrate via the alternating access mechanism, whereby the protein alternates between a conformation in which the substrate-binding site is accessible from the outside of the membrane, outward-facing and one in which it is inward-facing. In this mini-review, the structures of different ABC transporter types in different conformations are presented within the context of the alternating access mechanism and how they have shaped our current understanding of the mechanism of ABC transporters. © 2015 Authors; published by Portland Press Limited.

  2. ABC Transporters in Cancer Stem Cells: Beyond Chemoresistance.

    Science.gov (United States)

    Begicevic, Romana-Rea; Falasca, Marco

    2017-11-08

    The efficacy of chemotherapy is one of the main challenges in cancer treatment and one of the major obstacles to overcome in achieving lasting remission and a definitive cure in patients with cancer is the emergence of cancer resistance. Indeed, drug resistance is ultimately accountable for poor treatment outcomes and tumour relapse. There are various molecular mechanisms involved in multidrug resistance, such as the change in the activity of membrane transporters primarily belonging to the ATP binding cassette (ABC) transporter family. In addition, it has been proposed that this common feature could be attributed to a subpopulation of slow-cycling cancer stem cells (CSCs), endowed with enhanced tumorigenic potential and multidrug resistance. CSCs are characterized by the overexpression of specific surface markers that vary in different cancer cell types. Overexpression of ABC transporters has been reported in several cancers and more predominantly in CSCs. While the major focus on the role played by ABC transporters in cancer is polarized by their involvement in chemoresistance, emerging evidence supports a more active role of these proteins, in which they release specific bioactive molecules in the extracellular milieu. This review will outline our current understanding of the role played by ABC transporters in CSCs, how their expression is regulated and how they support the malignant metabolic phenotype. To summarize, we suggest that the increased expression of ABC transporters in CSCs may have precise functional roles and provide the opportunity to target, particularly these cells, by using specific ABC transporter inhibitors.

  3. ABC Transporters in Cancer Stem Cells: Beyond Chemoresistance

    Directory of Open Access Journals (Sweden)

    Romana-Rea Begicevic

    2017-11-01

    Full Text Available The efficacy of chemotherapy is one of the main challenges in cancer treatment and one of the major obstacles to overcome in achieving lasting remission and a definitive cure in patients with cancer is the emergence of cancer resistance. Indeed, drug resistance is ultimately accountable for poor treatment outcomes and tumour relapse. There are various molecular mechanisms involved in multidrug resistance, such as the change in the activity of membrane transporters primarily belonging to the ATP binding cassette (ABC transporter family. In addition, it has been proposed that this common feature could be attributed to a subpopulation of slow-cycling cancer stem cells (CSCs, endowed with enhanced tumorigenic potential and multidrug resistance. CSCs are characterized by the overexpression of specific surface markers that vary in different cancer cell types. Overexpression of ABC transporters has been reported in several cancers and more predominantly in CSCs. While the major focus on the role played by ABC transporters in cancer is polarized by their involvement in chemoresistance, emerging evidence supports a more active role of these proteins, in which they release specific bioactive molecules in the extracellular milieu. This review will outline our current understanding of the role played by ABC transporters in CSCs, how their expression is regulated and how they support the malignant metabolic phenotype. To summarize, we suggest that the increased expression of ABC transporters in CSCs may have precise functional roles and provide the opportunity to target, particularly these cells, by using specific ABC transporter inhibitors.

  4. Yeast ABC transporters in lipid trafficking.

    Science.gov (United States)

    Prasad, Rajendra; Khandelwal, Nitesh Kumar; Banerjee, Atanu

    2016-08-01

    Throughout its evolution, the ATP-binding cassette (ABC) transporter superfamily has experienced a rapid expansion in its substrate repertoire and functions. Of the diverse functions that these pumps offer, their drug transport properties have attracted considerable attention primarily owing to their clinical significance. Despite this fact, emerging evidence suggests that physiological substrates of transporters also affect the overall functioning of an organism. Lipids, as substrates of ABC transporters, constitute one feature found in all representative groups of the living kingdom. Due to the importance of lipid species in the cellular physiology of an organism, their proper distribution within cells is crucial. This fact is well exemplified by the vast number of medical conditions that have been caused as a result of perturbations in ABC transporter-mediated lipid transport in higher organisms. In yeasts, apart from providing transport functions, ABC transporters also coordinate regulatory networks with lipids. This review focuses on yeast ABC transporters involved in the transport of lipids and briefly discusses the integration of their regulatory network with that of the lipid species. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Export of recombinant proteins in Escherichia coli using ABC transporter with an attached lipase ABC transporter recognition domain (LARD

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    Moon Yuseok

    2009-01-01

    Full Text Available Abstract Background ATP binding cassette (ABC transporter secretes the protein through inner and outer membranes simultaneously in gram negative bacteria. Thermostable lipase (TliA of Pseudomonas fluorescens SIK W1 is secreted through the ABC transporter. TliA has four glycine-rich repeats (GGXGXD in its C-terminus, which appear in many ABC transporter-secreted proteins. From a homology model of TliA derived from the structure of P. aeruginosa alkaline protease (AprA, lipase ABC transporter domains (LARDs were designed for the secretion of fusion proteins. Results The LARDs included four glycine-rich repeats comprising a β-roll structure, and were added to the C-terminus of test proteins. Either Pro-Gly linker or Factor Xa site was added between fusion proteins and LARDs. We attached different length of LARDs such as LARD0, LARD1 or whole TliA (the longest LARD to three types of proteins; green fluorescent protein (GFP, epidermal growth factor (EGF and cytoplasmic transduction peptide (CTP. These fusion proteins were expressed in Escherichia coli together with ABC transporter of either P. fluorescens or Erwinia chrysanthemi. Export of fusion proteins with the whole TliA through the ABC transporter was evident on the basis of lipase enzymatic activity. Upon supplementation of E. coli with ABC transporter, GFP-LARDs and EGF-LARDs were excreted into the culture supernatant. Conclusion The LARDs or whole TliA were attached to C-termini of model proteins and enabled the export of the model proteins such as GFP and EGF in E. coli supplemented with ABC transporter. These results open the possibility for the extracellular production of recombinant proteins in Pseudomonas using LARDs or TliA as a C-terminal signal sequence.

  6. Tonoplast-localized Abc2 transporter mediates phytochelatin accumulation in vacuoles and confers cadmium tolerance.

    Science.gov (United States)

    Mendoza-Cózatl, David G; Zhai, Zhiyang; Jobe, Timothy O; Akmakjian, Garo Z; Song, Won-Yong; Limbo, Oliver; Russell, Matthew R; Kozlovskyy, Volodymyr I; Martinoia, Enrico; Vatamaniuk, Olena K; Russell, Paul; Schroeder, Julian I

    2010-12-24

    Phytochelatins mediate tolerance to heavy metals in plants and some fungi by sequestering phytochelatin-metal complexes into vacuoles. To date, only Schizosaccharomyces pombe Hmt1 has been described as a phytochelatin transporter and attempts to identify orthologous phytochelatin transporters in plants and other organisms have failed. Furthermore, recent data indicate that the hmt1 mutant accumulates significant phytochelatin levels in vacuoles, suggesting that unidentified phytochelatin transporters exist in fungi. Here, we show that deletion of all vacuolar ABC transporters abolishes phytochelatin accumulation in S. pombe vacuoles and abrogates (35)S-PC(2) uptake into S. pombe microsomal vesicles. Systematic analysis of the entire S. pombe ABC transporter family identified Abc2 as a full-size ABC transporter (ABCC-type) that mediates phytochelatin transport into vacuoles. The S. pombe abc1 abc2 abc3 abc4 hmt1 quintuple and abc2 hmt1 double mutant show no detectable phytochelatins in vacuoles. Abc2 expression restores phytochelatin accumulation into vacuoles and suppresses the cadmium sensitivity of the abc quintuple mutant. A novel, unexpected, function of Hmt1 in GS-conjugate transport is also shown. In contrast to Hmt1, Abc2 orthologs are widely distributed among kingdoms and are proposed as the long-sought vacuolar phytochelatin transporters in plants and other organisms.

  7. Phylogenetic analysis of fungal ABC transporters

    Directory of Open Access Journals (Sweden)

    Driessen Arnold JM

    2010-03-01

    Full Text Available Abstract Background The superfamily of ABC proteins is among the largest known in nature. Its members are mainly, but not exclusively, involved in the transport of a broad range of substrates across biological membranes. Many contribute to multidrug resistance in microbial pathogens and cancer cells. The diversity of ABC proteins in fungi is comparable with those in multicellular animals, but so far fungal ABC proteins have barely been studied. Results We performed a phylogenetic analysis of the ABC proteins extracted from the genomes of 27 fungal species from 18 orders representing 5 fungal phyla thereby covering the most important groups. Our analysis demonstrated that some of the subfamilies of ABC proteins remained highly conserved in fungi, while others have undergone a remarkable group-specific diversification. Members of the various fungal phyla also differed significantly in the number of ABC proteins found in their genomes, which is especially reduced in the yeast S. cerevisiae and S. pombe. Conclusions Data obtained during our analysis should contribute to a better understanding of the diversity of the fungal ABC proteins and provide important clues about their possible biological functions.

  8. Importance of ABC Transporters in Drug Development.

    Science.gov (United States)

    Benadiba, Marcel; Maor, Yehoshua

    2016-01-01

    ATP-binding cassette (ABC) transporters are a huge family of ATP-dependent transmembrane proteins whose main function is exporting or importing substances or molecules through the cell membranes, plasma cell membrane, or inner membranes in organelles. They fulfill these functions by maintaining cell integrity, metabolism, and homeostasis. They are expressed in a variety of tissues as they transport numerous essential compounds including lipids and other signaling molecules. ABC transporters became widely studied since the discovery of their ability to carry a multitude of xenobiotics, including therapeutic drugs, and in light of the fact that they represent a hurdle for the treatment of resistant cancers. In contrast, the role of ABC transporters in neurological diseases like Alzheimer`s and Parkinson`s, depression, schizophrenia, and epilepsy remains controversial and their mechanism of action in these pathologies remains elusive, thus hindering the implementation of therapies aimed at modulating the functions of these transporters. To date, a number of natural and synthetic compounds are known to act as inhibitors, substrates, and even inducers of these transporters, being able to modulate their expression and/or function; however, their implication as therapeutic agents is far from reaching wide clinical utilization. This review highlights the importance of overcoming the challenges posed by ABC transporters in drug development.

  9. Insight into Two ABC Transporter Families Involved in Lantibiotic Resistance

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    Rebecca Clemens

    2018-01-01

    Full Text Available Antimicrobial peptides, which contain (methyl-lanthionine-rings are called lantibiotics. They are produced by several Gram-positive bacteria and are mainly active against these bacteria. Although these are highly potent antimicrobials, some human pathogenic bacteria express specific ABC transporters that confer resistance and counteract their antimicrobial activity. Two distinct ABC transporter families are known to be involved in this process. These are the Cpr- and Bce-type ABC transporter families, named after their involvement in cationic peptide resistance in Clostridium difficile, and bacitracin efflux in Bacillus subtilis, respectively. Both resistance systems differentiate to each other in terms of the proteins involved. Here, we summarize the current knowledge and describe the divergence as well as the common features present in both the systems to confer lantibiotic resistance.

  10. ABC transporters in fish species: a review

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    Marta eFerreira

    2014-07-01

    Full Text Available ATP-binding cassette (ABC proteins were first recognized for their role in multidrug resistance (MDR in chemotherapeutic treatments, which is a major impediment for the successful treatment of many forms of malignant tumors in humans. These proteins, highly conserved throughout vertebrate species, were later related to cellular detoxification and accounted as responsible for protecting aquatic organisms from xenobiotic insults in the so-called multixenobiotic resistance mechanism (MXR. In recent years, research on these proteins in aquatic species has highlighted their importance in the detoxification mechanisms in fish thus it is of extreme added value to continue these studies. Several transporters have been pointed out as relevant in the ecotoxicological context associated to the transport of xenobiotics, such as P-glycoproteins (Pgps, multidrug-resistance-associated proteins (MRPs 1-5 and breast resistance associated protein (BCRP. In mammals, several nuclear receptors have been identified as mediators of phase I and II metabolizing enzymes and ABC transporters. In aquatic species, knowledge on co-regulation of detoxification mechanism is scarce and needs to be addressed. The interaction of emergent contaminants, with chemosensitizer potential, with ABC transporters in aquatic organisms can compromise detoxification processes and have population effects and should be studied in more detail. This review intends to summarize the recent advances in research on MXR mechanisms in fish species, focusing in 1 regulation and functioning of ABC proteins; 2 cooperation with phase I and II biotransformation enzymes; and 3 ecotoxicological relevance and information on emergent pollutants with ability to modulate ABC transporters expression and activity. Several lines of evidence are clear suggesting the important role of these transporters in detoxification mechanisms and must be further investigated in fish.

  11. Phylogenetic analysis of fungal ABC transporters

    NARCIS (Netherlands)

    Kovalchuk, Andriy; Driessen, Arnold J. M.

    2010-01-01

    Background: The superfamily of ABC proteins is among the largest known in nature. Its members are mainly, but not exclusively, involved in the transport of a broad range of substrates across biological membranes. Many contribute to multidrug resistance in microbial pathogens and cancer cells. The

  12. ABC transporters : Lessons from a bacterial oligopeptide uptake system

    NARCIS (Netherlands)

    Doeven, Mark Koop

    2006-01-01

    ABC transporters are proteins that are involved in the uptake of nutrients and excretion of harmful substances in biological cells. Defects in human ABC transporters can result in severe diseases. Too high ABC transporter activity can lead to non-responsiveness of cancercells to chemotherapy, and

  13. Functional analysis of candidate ABC transporter proteins for sitosterol transport

    DEFF Research Database (Denmark)

    Albrecht, C; Elliott, J I; Sardini, A

    2002-01-01

    Two ATP-binding cassette (ABC) proteins, ABCG5 and ABCG8, have recently been associated with the accumulation of dietary cholesterol in the sterol storage disease sitosterolemia. These two 'half-transporters' are assumed to dimerize to form the complete sitosterol transporter which reduces...... the absorption of sitosterol and related molecules in the intestine by pumping them back into the lumen. Although mutations altering ABCG5 and ABCG8 are found in affected patients, no functional demonstration of sitosterol transport has been achieved. In this study, we investigated whether other ABC transporters......-specific ABC transporters have acquired specificity to exclude sitosterol and related sterols like cholesterol presumably because the abundance of cholesterol in the membrane would interfere with their action; in consequence, specific transporters have evolved to handle these sterols....

  14. Abc1: a new ABC transporter from the fission yeast Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Christensen, P U; Davis, K; Nielsen, O

    1997-01-01

    We have isolated the abc1 gene from the fission yeast Schizosaccharomyces pombe. Sequence analysis suggests that the Abc1 protein is a member of the ABC superfamily of transporters and is composed of two structurally homologous halves, each consisting of a hydrophobic region of six transmembrane...... domains and a hydrophilic region containing one ATP-binding site. The abc1 gene appears to be expressed under all growth conditions but gene disruption experiments indicate that it is not essential for growth. The sequence of the abc1 gene has been deposited in the EMBL data library under the Accession...

  15. Functional analysis of candidate ABC transporter proteins for sitosterol transport

    DEFF Research Database (Denmark)

    Albrecht, C; Elliott, J I; Sardini, A

    2002-01-01

    Two ATP-binding cassette (ABC) proteins, ABCG5 and ABCG8, have recently been associated with the accumulation of dietary cholesterol in the sterol storage disease sitosterolemia. These two 'half-transporters' are assumed to dimerize to form the complete sitosterol transporter which reduces the ab...

  16. Isolation and Characterization of the Colletotrichum acutatum ABC Transporter CaABC1

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    Suyoung Kim

    2014-12-01

    Full Text Available Fungi tolerate exposure to various abiotic stresses, including cytotoxic compounds and fungicides, via their ATP-driven efflux pumps belonging to ATP-binding cassette (ABC transporters. To clarify the molecular basis of interaction between the fungus and various abiotic stresses including fungicides, we constructed a cDNA library from germinated conidia of Colletotrichum acutatum, a major anthracnose pathogen of pepper (Capsicum annum L.. Over 1,000 cDNA clones were sequenced, of which single clone exhibited significant nucleotide sequence homology to ABC transporter genes. We isolated three fosmid clones containing the C. acutatum ABC1 (CaABC1 gene in full-length from genomic DNA library screening. The CaABC1 gene consists of 4,059 bp transcript, predicting a 1,353-aa protein. The gene contains the typical ABC signature and Walker A and B motifs. The 5′-flanking region contains a CAAT motif, a TATA box, and a Kozak region. Phylogenetic and structural analysis suggested that the CaABC1 is a typical ABC transporter gene highly conserved in various fungal species, as well as in Chromista, Metazoans, and Viridiplantae. We also found that CaABC1 was up-regulated during conidiation and a minimal medium condition. Moreover, CaABC1 was induced in iprobenfos, kresoxim-methyl, thiophanate-methyl, and hygromycin B. These results demonstrate that CaABC1 is necessary for conidiation, abiotic stress, and various fungicide resistances. These results will provide the basis for further study on the function of ABC transporter genes in C. acutatum.

  17. Current advances on ABC drug transporters in fish.

    Science.gov (United States)

    Luckenbach, Till; Fischer, Stephan; Sturm, Armin

    2014-09-01

    Most members of the large ATP-binding cassette (ABC) gene family are transporters involved in substrate translocation across biological membranes. In eukaryotes, ABC proteins functioning as drug transporters are located in the plasma membrane and mediate the cellular efflux of a wide range of organic chemicals, with some transporters also transporting certain metals. As the enhanced expression of ABC drug transporters can confer multidrug resistance (MDR) to cancers and multixenobiotic resistance (MXR) to organisms from polluted habitats, these ABC family members are also referred to as MDR or MXR proteins. In mammals, ABC drug transporters show predominant expression in tissues involved in excretion or constituting internal or external body boundaries, where they facilitate the excretion of chemicals and their metabolites, and limit chemical uptake and penetration into "sanctuary" sites of the body. Available knowledge about ABC proteins is still limited in teleost fish, a large vertebrate group of high ecological and economic importance. Using transport activity measurements and immunochemical approaches, early studies demonstrated similarities in the tissue distribution of ABC drug transporters between teleosts and mammals, suggesting conserved roles of the transporters in the biochemical defence against toxicants. Recently, the availability of teleost genome assemblies has stimulated studies of the ABC family in this taxon. This review summarises the current knowledge regarding the genetics, functional properties, physiological function, and ecotoxicological relevance of teleostean ABC transporters. The available literature is reviewed with emphasis on recent studies addressing the tissue distribution, substrate spectrum, regulation, physiological function and phylogenetic origin of teleostean ABC transporters. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Human ATP-binding cassette (ABC transporter family

    Directory of Open Access Journals (Sweden)

    Vasiliou Vasilis

    2009-04-01

    Full Text Available Abstract There exist four fundamentally different classes of membrane-bound transport proteins: ion channels; transporters; aquaporins; and ATP-powered pumps. ATP-binding cassette (ABC transporters are an example of ATP-dependent pumps. ABC transporters are ubiquitous membrane-bound proteins, present in all prokaryotes, as well as plants, fungi, yeast and animals. These pumps can move substrates in (influx or out (efflux of cells. In mammals, ABC transporters are expressed predominantly in the liver, intestine, blood-brain barrier, blood-testis barrier, placenta and kidney. ABC proteins transport a number of endogenous substrates, including inorganic anions, metal ions, peptides, amino acids, sugars and a large number of hydrophobic compounds and metabolites across the plasma membrane, and also across intracellular membranes. The human genome contains 49 ABC genes, arranged in eight subfamilies and named via divergent evolution. That ABC genes are important is underscored by the fact that mutations in at least I I of these genes are already known to cause severe inherited diseases (eg cystic fibrosis and X-linked adrenoleukodystrophy [X-ALD]. ABC transporters also participate in the movement of most drugs and their metabolites across cell surface and cellular organelle membranes; thus, defects in these genes can be important in terms of cancer therapy, pharmacokinetics and innumerable pharmacogenetic disorders.

  19. Expression pattern of the human ABC transporters in pluripotent embryonic stem cells and in their derivatives.

    Science.gov (United States)

    Erdei, Zsuzsa; Lőrincz, Réka; Szebényi, Kornélia; Péntek, Adrienn; Varga, Nóra; Likó, István; Várady, György; Szakács, Gergely; Orbán, Tamás I; Sarkadi, Balázs; Apáti, Agota

    2014-09-01

    ATP-binding cassette (ABC) transporters have key roles in various physiological functions as well as providing chemical defense and stress tolerance in human tissues. In this study, we have examined the expression pattern of all ABC proteins in pluripotent human embryonic stem cells (hESCs) and in their differentiated progenies. We paid special attention to the cellular expression and localization of multidrug transporter ABC proteins. Stem cell differentiation was carried out without chemical induction or cell sorting, and specialized cell types were separated mechanically. Cellular features regarding pluripotency and tissue identity, as well as ABC transporter expression were studied by flow cytomtery, immuno-microscopy, and qPCR-based low-density arrays. Pluripotent hESCs and differentiated cell types (cardiomyocytes, neuronal cells, and mesenchymal stem cells) were distinguished by morphology, immunostaining markers, and selected mRNA expression patterns. We found that the mRNA expression levels of the 48 human ABC proteins also clearly distinguished the pluripotent and the respective differentiated cell types. When multidrug and lipid transporter ABC protein expression was examined by using well characterized specific antibodies by flow cytometry and confocal microscopy, the protein expression data corresponded well to the mRNA expression results. Moreover, the cellular localization of these important human ABC transporter proteins could be established in the pluripotent and differentiated hESC derived samples. These studies provide valuable information regarding ABC protein expression in human stem cells and their differentiated offspring. The results may also help to obtain further information concerning the specialized cellular functions of selected ABC transporters. © 2014 Clinical Cytometry Society.

  20. Polymorphism in ABC transporter genes of Dirofilaria immitis

    Directory of Open Access Journals (Sweden)

    Thangadurai Mani

    2017-08-01

    Full Text Available Dirofilaria immitis, a filarial nematode, causes dirofilariasis in dogs, cats and occasionally in humans. Prevention of the disease has been mainly by monthly use of the macrocyclic lactone (ML endectocides during the mosquito transmission season. Recently, ML resistance has been confirmed in D. immitis and therefore, there is a need to find new classes of anthelmintics. One of the mechanisms associated with ML resistance in nematodes has been the possible role of ATP binding cassette (ABC transporters in reducing drug concentrations at receptor sites. ABC transporters, mainly from sub-families B, C and G, may contribute to multidrug resistance (MDR by active efflux of drugs out of the cell. Gene products of ABC transporters may thus serve as the targets for agents that may modulate susceptibility to drugs, by inhibiting drug transport. ABC transporters are believed to be involved in a variety of physiological functions critical to the parasite, such as sterol transport, and therefore may also serve as the target for drugs that can act as anthelmintics on their own. Knowledge of polymorphism in these ABC transporter genes in nematode parasites could provide useful information for the process of drug design. We have identified 15 ABC transporter genes from sub-families A, B, C and G, in D. immitis, by comparative genomic approaches and analyzed them for polymorphism. Whole genome sequencing data from four ML susceptible (SUS and four loss of efficacy (LOE pooled populations were used for single nucleotide polymorphism (SNP genotyping. Out of 231 SNPs identified in those 15 ABC transporter genes, 89 and 75 of them were specific to the SUS or LOE populations, respectively. A few of the SNPs identified may affect gene expression, protein function, substrate specificity or resistance development and may be useful for transporter inhibitor/anthelmintic drug design, or in order to anticipate resistance development. Keywords: Dirofilaria immitis

  1. Identification of ABC transporters acting in vitamin B12metabolism in Caenorhabditis elegans.

    Science.gov (United States)

    McDonald, Megan K; Fritz, Julie-Anne; Jia, Dongxin; Scheuchner, Deborah; Snyder, Floyd F; Stanislaus, Avalyn; Curle, Jared; Li, Liang; Stabler, Sally P; Allen, Robert H; Mains, Paul E; Gravel, Roy A

    2017-12-01

    Vitamin B 12 (cobalamin, Cbl) is a micronutrient essential to human health. Cbl is not utilized as is but must go through complex subcellular and metabolic processing to generate two cofactor forms: methyl-Cbl for methionine synthase, a cytosolic enzyme; and adenosyl-Cbl for methylmalonyl-CoA mutase, a mitochondrial enzyme. Some 10-12 human genes have been identified responsible for the intracellular conversion of Cbl to cofactor forms, including genes that code for ATP-binding cassette (ABC) transporters acting at the lysosomal and plasma membranes. However, the gene for mitochondrial uptake is not known. We hypothesized that ABC transporters should be candidates for other uptake and efflux functions, including mitochondrial transport, and set out to screen ABC transporter mutants for blocks in Cbl utilization using the nematode roundworm Caenorhabditis elegans. Thirty-seven mutant ABC transporters were screened for the excretion of methylmalonic acid (MMA), which should result from loss of Cbl transport into the mitochondria. One mutant, wht-6, showed elevated MMA excretion and reduced [ 14 C]-propionate incorporation, pointing to a functional block in methylmalonyl-CoA mutase. In contrast, the wht-6 mutant appeared to have a normal cytosolic pathway based on analysis of cystathionine excretion, suggesting that cytosolic methionine synthase was functioning properly. Further, the MMA excretion in wht-6 could be partially reversed by including vitamin B 12 in the assay medium. The human ortholog of wht-6 is a member of the G family of ABC transporters. We propose wht-6 as a candidate for the transport of Cbl into mitochondria and suggest that a member of the corresponding ABCG family of ABC transporters has this role in humans. Our ABC transporter screen also revealed that mrp-1 and mrp-2 mutants excreted lower MMA than wild type, suggesting they were concentrating intracellular Cbl, consistent with the cellular efflux defect proposed for the mammalian MRP1 ABC

  2. ABC transporter research: going strong 40 years on.

    Science.gov (United States)

    Theodoulou, Frederica L; Kerr, Ian D

    2015-10-01

    In most organisms, ABC transporters constitute one of the largest families of membrane proteins. In humans, their functions are diverse and underpin numerous key physiological processes, as well as being causative factors in a number of clinically relevant pathologies. Advances in our understanding of these diseases have come about through combinations of genetic and protein biochemical investigations of these transporters and the power of in vitro and in vivo investigations is helping to develop genotype-phenotype understanding. However, the importance of ABC transporter research goes far beyond human biology; microbial ABC transporters are of great interest in terms of understanding virulence and drug resistance and industrial biotechnology researchers are exploring the potential of prokaryotic ABC exporters to increase the capacity of synthetic biology systems. Plant ABC transporters play important roles in transport of hormones, xenobiotics, metals and secondary metabolites, pathogen responses and numerous aspects of development, all of which are important in the global food security area. For 3 days in Chester, this Biochemical Society Focused Meeting brought together researchers with diverse experimental approaches and with different fundamental questions, all of which are linked by the commonality of ABC transporters. © 2015 Authors.

  3. ABC Transport Proteins in Cardiovascular Disease-A Brief Summary.

    Science.gov (United States)

    Schumacher, Toni; Benndorf, Ralf A

    2017-04-06

    Adenosine triphosphate (ATP)-binding cassette (ABC) transporters may play an important role in the pathogenesis of atherosclerotic vascular diseases due to their involvement in cholesterol homeostasis, blood pressure regulation, endothelial function, vascular inflammation, as well as platelet production and aggregation. In this regard, ABC transporters, such as ABCA1, ABCG5 and ABCG8, were initially found to be responsible for genetically-inherited syndromes like Tangier diseases and sitosterolemia. These findings led to the understanding of those transporter's function in cellular cholesterol efflux and thereby also linked them to atherosclerosis and cardiovascular diseases (CVD). Subsequently, further ABC transporters, i.e., ABCG1, ABCG4, ABCB6, ABCC1, ABCC6 or ABCC9, have been shown to directly or indirectly affect cellular cholesterol efflux, the inflammatory response in macrophages, megakaryocyte proliferation and thrombus formation, as well as vascular function and blood pressure, and may thereby contribute to the pathogenesis of CVD and its complications. Furthermore, ABC transporters, such as ABCB1, ABCC2 or ABCG2, may affect the safety and efficacy of several drug classes currently in use for CVD treatment. This review will give a brief overview of ABC transporters involved in the process of atherogenesis and CVD pathology. It also aims to briefly summarize the role of ABC transporters in the pharmacokinetics and disposition of drugs frequently used to treat CVD and CVD-related complications.

  4. ATP-binding cassette (ABC transporters in normal and pathological lung

    Directory of Open Access Journals (Sweden)

    Timmer-Bosscha Hetty

    2005-06-01

    Full Text Available Abstract ATP-binding cassette (ABC transporters are a family of transmembrane proteins that can transport a wide variety of substrates across biological membranes in an energy-dependent manner. Many ABC transporters such as P-glycoprotein (P-gp, multidrug resistance-associated protein 1 (MRP1 and breast cancer resistance protein (BCRP are highly expressed in bronchial epithelium. This review aims to give new insights in the possible functions of ABC molecules in the lung in view of their expression in different cell types. Furthermore, their role in protection against noxious compounds, e.g. air pollutants and cigarette smoke components, will be discussed as well as the (malfunction in normal and pathological lung. Several pulmonary drugs are substrates for ABC transporters and therefore, the delivery of these drugs to the site of action may be highly dependent on the presence and activity of many ABC transporters in several cell types. Three ABC transporters are known to play an important role in lung functioning. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR gene can cause cystic fibrosis, and mutations in ABCA1 and ABCA3 are responsible for respectively Tangier disease and fatal surfactant deficiency. The role of altered function of ABC transporters in highly prevalent pulmonary diseases such as asthma or chronic obstructive pulmonary disease (COPD have hardly been investigated so far. We especially focused on polymorphisms, knock-out mice models and in vitro results of pulmonary research. Insight in the function of ABC transporters in the lung may open new ways to facilitate treatment of lung diseases.

  5. ABC-B transporter genes in Dirofilaria immitis.

    Science.gov (United States)

    Bourguinat, Catherine; Che, Hua; Mani, Thangadurai; Keller, Kathy; Prichard, Roger K

    2016-08-01

    Dirofilaria immitis is a filarial nematode causing infection and heartworm disease in dogs and other canids, cats, and occasionally in humans. Prevention with macrocyclic lactones (ML) is recommended during the mosquito transmission season. Recently, ML resistance has been reported. ABC-B transporter genes are thought to be involved in the mechanism of ML resistance in other nematodes. This study aimed to identify all the ABC-B transporter genes in D. immitis using as a reference the nDi.2.2 D. immitis whole genome, which is not completely annotated. Using bioinformatic tools and PCR amplification on pooled D. immitis genomic DNA and on pooled cDNA, nine ABC transporter genes including one pseudogene were characterized. Bioinformatic and phylogenetic analyses allowed identification of three P-glycoproteins (Pgps) (Dim-pgp-3 Dim-pgp-10, Dim-pgp-11), of two ABC-B half transporter genes (one ortholog of Cel-haf-4 and Cel-haf-9; and one ortholog of Cel-haf-1 and Cel-haf-3), of one ABC half transporter gene (ortholog of Cel-haf-5) that contained an ABC-C motif, and of one additional half transporter that would require functional study for characterization. The number of ABC-B transporter genes identified was lower than in Caenorhabditis elegans and Haemonchus contortus. Further studies are needed to understand their possible role in ML resistance in D. immitis. These ABC transporters constitute a base for ML resistance investigation in D. immitis and advance our understanding of the molecular biology of this parasite. Copyright © 2016. Published by Elsevier Ltd.

  6. ATP binding cassette (ABC) transporters: expression and clinical value in glioblastoma.

    Science.gov (United States)

    Dréan, Antonin; Rosenberg, Shai; Lejeune, François-Xavier; Goli, Larissa; Nadaradjane, Aravindan Arun; Guehennec, Jérémy; Schmitt, Charlotte; Verreault, Maïté; Bielle, Franck; Mokhtari, Karima; Sanson, Marc; Carpentier, Alexandre; Delattre, Jean-Yves; Idbaih, Ahmed

    2018-03-08

    ATP-binding cassette transporters (ABC transporters) regulate traffic of multiple compounds, including chemotherapeutic agents, through biological membranes. They are expressed by multiple cell types and have been implicated in the drug resistance of some cancer cells. Despite significant research in ABC transporters in the context of many diseases, little is known about their expression and clinical value in glioblastoma (GBM). We analyzed expression of 49 ABC transporters in both commercial and patient-derived GBM cell lines as well as from 51 human GBM tumor biopsies. Using The Cancer Genome Atlas (TCGA) cohort as a training dataset and our cohort as a validation dataset, we also investigated the prognostic value of these ABC transporters in newly diagnosed GBM patients, treated with the standard of care. In contrast to commercial GBM cell lines, GBM-patient derived cell lines (PDCL), grown as neurospheres in a serum-free medium, express ABC transporters similarly to parental tumors. Serum appeared to slightly increase resistance to temozolomide correlating with a tendency for an increased expression of ABCB1. Some differences were observed mainly due to expression of ABC transporters by microenvironmental cells. Together, our data suggest that the efficacy of chemotherapeutic agents may be misestimated in vitro if they are the targets of efflux pumps whose expression can be modulated by serum. Interestingly, several ABC transporters have prognostic value in the TCGA dataset. In our cohort of 51 GBM patients treated with radiation therapy with concurrent and adjuvant temozolomide, ABCA13 overexpression is associated with a decreased progression free survival in univariate (p ABC transporters is: (i) detected in GBM and microenvironmental cells and (ii) better reproduced in GBM-PDCL. ABCA13 expression is an independent prognostic factor in newly diagnosed GBM patients. Further prospective studies are warranted to investigate whether ABCA13 expression can be

  7. Dual fluorescent labelling of the human malaria parasite Plasmodium falciparum for the analysis of the ABC type transporter pfmdr2

    Directory of Open Access Journals (Sweden)

    Rosental Benyamin

    2012-11-01

    Full Text Available Abstract Background The study of the Plasmodium falciparum heavy metal transporter gene pfmdr2 employed radioactive labelled heavy metal. As the use of radioactive isotopes shrank considerably during the last few years, resulting in the cessation of the production of some isotopes, amongst them Cadmium109 which was used for that purpose, a different approach had to be developed. Herein, a dual fluorescent labelling of heavy metals accumulation in the P. falciparum parasite is proposed as an alternative to the use of radioactive labelled heavy metals. Methods Plasmodium falciparum Cd resistant and sensitive strains at the trophozoite stage were used in this study. The cells were cultured at different CdCl2 concentrations and for different time periods followed by staining of the infected red blood cells with Fluo-3/AM for Cd detection and Hoechst 33342 for parasite DNA labelling. The fluorescent analysis was done by flow cytometry and confocal microscopy. Results The results show that the sensitive strain has a higher Fluo-3/AM fluorescence in a Cd concentration and time dependent manner, whereas in the resistant strain Fluo-3/AM fluorescence levels were negligible and increased only at high concentrations of Cd and at long incubation periods, but to a much lesser extent than the sensitive strain. No Cd uptake is observed in uninfected red blood cells populations originating from cultures infected with either sensitive or resistant strain. In addition, confocal microscopy overlay of Fluo-3/AM and Hoechst staining shows that the Cd metal accumulates in the parasite itself. Conclusions The dual fluorescent labelling is a valid method for detecting heavy metal accumulation in P. falciparum. Furthermore, in contrast to the use of radioactive labelled heavy metal, the fluorescent labelling enables us to differentiate between the different populations existing in a P. falciparum infected red blood cells cultures and thus actually study a phenomenon at

  8. Polymorphism in ABC transporter genes of Dirofilaria immitis.

    Science.gov (United States)

    Mani, Thangadurai; Bourguinat, Catherine; Prichard, Roger K

    2017-08-01

    Dirofilaria immitis, a filarial nematode, causes dirofilariasis in dogs, cats and occasionally in humans. Prevention of the disease has been mainly by monthly use of the macrocyclic lactone (ML) endectocides during the mosquito transmission season. Recently, ML resistance has been confirmed in D. immitis and therefore, there is a need to find new classes of anthelmintics. One of the mechanisms associated with ML resistance in nematodes has been the possible role of ATP binding cassette (ABC) transporters in reducing drug concentrations at receptor sites. ABC transporters, mainly from sub-families B, C and G, may contribute to multidrug resistance (MDR) by active efflux of drugs out of the cell. Gene products of ABC transporters may thus serve as the targets for agents that may modulate susceptibility to drugs, by inhibiting drug transport. ABC transporters are believed to be involved in a variety of physiological functions critical to the parasite, such as sterol transport, and therefore may also serve as the target for drugs that can act as anthelmintics on their own. Knowledge of polymorphism in these ABC transporter genes in nematode parasites could provide useful information for the process of drug design. We have identified 15 ABC transporter genes from sub-families A, B, C and G, in D. immitis, by comparative genomic approaches and analyzed them for polymorphism. Whole genome sequencing data from four ML susceptible (SUS) and four loss of efficacy (LOE) pooled populations were used for single nucleotide polymorphism (SNP) genotyping. Out of 231 SNPs identified in those 15 ABC transporter genes, 89 and 75 of them were specific to the SUS or LOE populations, respectively. A few of the SNPs identified may affect gene expression, protein function, substrate specificity or resistance development and may be useful for transporter inhibitor/anthelmintic drug design, or in order to anticipate resistance development. Copyright © 2017 The Authors. Published by

  9. An ABC-transporter and an outer membrane lipoprotein participate in posttranslational activation of type VI secretion in Pseudomonas aeruginosa

    Science.gov (United States)

    Casabona, Maria G.; Silverman, Julie M.; Sall, Khady M.; Boyer, Frédéric; Couté, Yohann; Poirel, Jessica; Grunwald, Didier; Mougous, Joseph D.; Elsen, Sylvie; Attree, Ina

    2012-01-01

    Pseudomonas aeruginosa is capable of injecting protein toxins into other bacterial cells through one of its three type VI secretion systems (T6SS). The activity of this T6SS is tightly regulated on the posttranslational level by phosphorylation-dependent and -independent pathways. The phosphorylation-dependent pathway consists of a Thr kinase/phosphatase pair (PpkA/PppA) that acts on a forkhead domain-containing protein Fha1, and a periplasmic protein, TagR, that positively regulates PpkA. In the present work, we biochemically and functionally characterize three additional proteins of the phosphorylation-dependent regulatory cascade that controls T6S activation: TagT, TagS and TagQ. We show that similar to TagR, these proteins act upstream of the PpkA/PppA checkpoint and influence phosphorylation of Fha1 and export of Hcp1 and Tse1. Localization studies demonstrate that TagQ is an outer membrane lipoprotein and TagR is associated with the outer membrane. Consistent with their homology to lipoprotein outer membrane localization (Lol) components, TagT and TagS form a stable inner membrane complex with ATPase activity. However, we find that outer membrane association of T6SS lipoproteins TagQ and TssJ1, and TagR, is unaltered in a ΔtagTS background. Notably, we found that TagQ is indispensible for anchoring of TagR to the outer membrane fraction. As T6S-dependent fitness of P. aeruginosa requires TagT, S, R and Q, we conclude that these proteins likely participate in a trans-membrane signaling pathway that promotes H1-T6SS activity under optimal environmental conditions. PMID:22765374

  10. An ABC transporter and an outer membrane lipoprotein participate in posttranslational activation of type VI secretion in Pseudomonas aeruginosa.

    Science.gov (United States)

    Casabona, Maria G; Silverman, Julie M; Sall, Khady M; Boyer, Frédéric; Couté, Yohann; Poirel, Jessica; Grunwald, Didier; Mougous, Joseph D; Elsen, Sylvie; Attree, Ina

    2013-02-01

    Pseudomonas aeruginosa is capable of injecting protein toxins into other bacterial cells through one of its three type VI secretion systems (T6SSs). The activity of this T6SS is tightly regulated on the posttranslational level by phosphorylation-dependent and -independent pathways. The phosphorylation-dependent pathway consists of a Threonine kinase/phosphatase pair (PpkA/PppA) that acts on a forkhead domain-containing protein, Fha1, and a periplasmic protein, TagR, that positively regulates PpkA. In the present work, we biochemically and functionally characterize three additional proteins of the phosphorylation-dependent regulatory cascade that controls T6S activation: TagT, TagS and TagQ. We show that similar to TagR, these proteins act upstream of the PpkA/PppA checkpoint and influence phosphorylation of Fha1 and, apparatus assembly and effector export. Localization studies demonstrate that TagQ is an outer membrane lipoprotein and TagR is associated with the outer membrane. Consistent with their homology to lipoprotein outer membrane localization (Lol) components, TagT and TagS form a stable inner membrane complex with ATPase activity. However, we find that outer membrane association of T6SS lipoproteins TagQ and TssJ1, and TagR, is unaltered in a ΔtagTS background. Notably, we found that TagQ is indispensible for anchoring of TagR to the outer membrane fraction. As T6S-dependent fitness of P. aeruginosa requires TagT, S, R and Q, we conclude that these proteins likely participate in a trans-membrane signalling pathway that promotes H1-T6SS activity under optimal environmental conditions. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  11. ABC transporters in the liver fluke Opisthorchis felineus.

    Science.gov (United States)

    Mordvinov, Viatcheslav A; Ershov, Nikita I; Pirozhkova, Darya S; Pakharukov, Yuri V; Pakharukova, Maria Y

    2017-09-01

    ATP-binding cassette transporters (ABC transporters) are essential components of normal cellular physiological machinery in all eukaryotic and prokaryotic species, including parasites. Some ABC transporters, e.g., P-glycoproteins, are involved in the efflux of toxins and xenobiotics from the cell. At present, nothing is known about ABC transporter genes in epidemiologically important liver flukes from the Opisthorchiidae family, including European liver fluke Opisthorchis felineus. Opisthorchiasis caused by O. felineus is a serious public health problem on the territory of Russia and other Eastern European countries. ABC drug transporters are attractive objects of research on molecular markers of resistance and on ways to potentiate sensitivity to anthelmintics through suppression of the transporters themselves with specific inhibitors. Here we aimed at the identification of ABC transporters in the O. felineus transcriptome and identification of P-glycoproteins. In addition, our aim was to assess ABC transcript abundance in the RNA-seq data, to study the mRNA expression of P-glycoprotein genes by Droplet Digital PCR throughout the life cycle of O. felineus, and to test the gene induction in response to xenobiotics or anthelminthic agents. We found 23 nucleotide sequences encoding ABC transporters belonging to different subfamilies, including four sequences of P-glycoproteins. According to the transcript abundance in the RNA-seq data, one of P-glycoproteins (P4) has the highest expression among all ABC genes in the adult worm. P-glycoproteins showed substantially differential mRNA expression throughout the fluke life cycle, with high expression in the adult worms. Putative activity of P-glycoproteins as xenobiotic efflux pumps was found to be linked to the excretory system of O. felineus and to be inhibited by verapamil or tariquidar. Thus, ABC drug transporters in the liver fluke O. felineus are functionally active, indicating that ABC drug transporters are likely

  12. Transportomics: screening for substrates of ABC transporters in body fluids using vesicular transport assays

    NARCIS (Netherlands)

    Krumpochova, Petra; Sapthu, Sunny; Brouwers, Jos F.; de Haas, Marcel; de Vos, Ric; Borst, Piet; van de Wetering, Koen

    2012-01-01

    The ATP-binding cassette (ABC) genes encode the largest family of transmembrane proteins. ABC transporters translocate a wide variety of substrates across membranes, but their physiological function is often incompletely understood. We describe a new method to study the substrate spectrum of ABC

  13. Comparison of mechanistic transport cycle models of ABC exporters.

    Science.gov (United States)

    Szöllősi, Dániel; Rose-Sperling, Dania; Hellmich, Ute A; Stockner, Thomas

    2018-04-01

    ABC (ATP binding cassette) transporters, ubiquitous in all kingdoms of life, carry out essential substrate transport reactions across cell membranes. Their transmembrane domains bind and translocate substrates and are connected to a pair of nucleotide binding domains, which bind and hydrolyze ATP to energize import or export of substrates. Over four decades of investigations into ABC transporters have revealed numerous details from atomic-level structural insights to their functional and physiological roles. Despite all these advances, a comprehensive understanding of the mechanistic principles of ABC transporter function remains elusive. The human multidrug resistance transporter ABCB1, also referred to as P-glycoprotein (P-gp), is one of the most intensively studied ABC exporters. Using ABCB1 as the reference point, we aim to compare the dominating mechanistic models of substrate transport and ATP hydrolysis for ABC exporters and to highlight the experimental and computational evidence in their support. In particular, we point out in silico studies that enhance and complement available biochemical data. "This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain." Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Asymmetric switching in a homodimeric ABC transporter: a simulation study.

    Directory of Open Access Journals (Sweden)

    Jussi Aittoniemi

    2010-04-01

    Full Text Available ABC transporters are a large family of membrane proteins involved in a variety of cellular processes, including multidrug and tumor resistance and ion channel regulation. Advances in the structural and functional understanding of ABC transporters have revealed that hydrolysis at the two canonical nucleotide-binding sites (NBSs is co-operative and non-simultaneous. A conserved core architecture of bacterial and eukaryotic ABC exporters has been established, as exemplified by the crystal structure of the homodimeric multidrug exporter Sav1866. Currently, it is unclear how sequential ATP hydrolysis arises in a symmetric homodimeric transporter, since it implies at least transient asymmetry at the NBSs. We show by molecular dynamics simulation that the initially symmetric structure of Sav1866 readily undergoes asymmetric transitions at its NBSs in a pre-hydrolytic nucleotide configuration. MgATP-binding residues and a network of charged residues at the dimer interface are shown to form a sequence of putative molecular switches that allow ATP hydrolysis only at one NBS. We extend our findings to eukaryotic ABC exporters which often consist of two non-identical half-transporters, frequently with degeneracy substitutions at one of their two NBSs. Interestingly, many residues involved in asymmetric conformational switching in Sav1866 are substituted in degenerate eukaryotic NBS. This finding strengthens recent suggestions that the interplay of a consensus and a degenerate NBS in eukaroytic ABC proteins pre-determines the sequence of hydrolysis at the two NBSs.

  15. ABC transporters in Arthropods: genomic comparison and role in insecticide transport and resistance

    NARCIS (Netherlands)

    Dermauw, W.; Van Leeuwen, T.

    2014-01-01

    About a 100 years ago, the Drosophila white mutant marked the birth of Drosophila genetics. The white gene turned out to encode the first well studied ABC transporter in arthropods. The ABC gene family is now recognized as one of the largest transporter families in all kingdoms of life. The majority

  16. ABC transporters of the wheat pathogen Mycosphaerella graminicola

    NARCIS (Netherlands)

    Zwiers, L.H.

    2002-01-01

    A TP- b inding c assette (ABC) transporters belong to one of the largest protein families known. They play a role in numerous vital processes in the cell and are characterised by their

  17. ABC transporters van Botrytis cinerea in biotische en abiotische interacties

    NARCIS (Netherlands)

    Schoonbeek, H.

    2005-01-01

    Op 29 november 2004 promoveerde Henk-jan Schoonbeek aan Wageningen Universiteit op het proefschrift getiteld 'ABC transporters from Botrytis cinerea in biotic and abiotic interactions'. Promotor was Prof. dr. ir. P.J.G.M. de Wit en co-promotor was dr.ir. M.A. de Waard, leerstoelgroep Fytopathologie,

  18. ABC transporters from Botrytis cinerea in biotic and abiotic interactions

    NARCIS (Netherlands)

    Schoonbeek, H.

    2004-01-01

    Botrytis cinereais the causal agent of grey mould disease on a wide variety of crop plants. It is relatively insensitive to natural and synthetic fungitoxic compounds. This thesis describes how ABC (ATP-binding cassette) transporters contribute to protection by actively

  19. Inventory, assembly and analysis of Bacillus subtilis ABC transport systems.

    Science.gov (United States)

    Quentin, Y; Fichant, G; Denizot, F

    1999-04-02

    We have undertaken the inventory and assembly of the ATP binding cassette (ABC) transporter systems in the complete genome of Bacillus subtilis. We combined the identification of the three protein partners that compose an ABC transporter (nucleotide-binding domain, NBD; membrane spanning domain, MSD; and solute-binding protein, SBP) with constraints on the genetic organization. This strategy allowed the identification of 86 NBDs in 78 proteins, 103 MSD proteins and 37 SBPs. The analysis of transcriptional units allows the reconstruction of 59 ABC transporters, which include at least one NBD and one MSD. A particular class of five dimeric ATPases was not associated to MSD partners and is assumed to be involved either in macrolide resistance or regulation of translation elongation. In addition, we have detected five genes encoding ATPases without any gene coding for MSD protein in their neighborhood and 11 operons that encode only the membrane and solute-binding proteins. On the bases of similarities, three ATP-binding proteins are proposed to energize ten incomplete systems, suggesting that one ATPase may be recruited by more than one transporter. Finally, we estimate that the B. subtilis genome encodes for at least 78 ABC transporters that have been split in 38 importers and 40 extruders. The ABC systems have been further classified into 11 sub-families according to the tree obtained from the NBDs and the clustering of the MSDs and the SBPs. Comparisons with Escherichia coli show that the extruders are over-represented in B. subtilis, corresponding to an expansion of the sub-families of antibiotic and drug resistance systems. Copyright 1999 Academic Press.

  20. Hepatic ABC transporters and triglyceride metabolism.

    Science.gov (United States)

    Parks, John S; Chung, Soonkyu; Shelness, Gregory S

    2012-06-01

    Elevated plasma triglyceride and reduced HDL concentrations are prominent features of metabolic syndrome and type 2 diabetes. Individuals with Tangier disease also have elevated plasma triglyceride concentrations and very low HDL, resulting from mutations in ATP-binding cassette transporter A1 (ABCA1), an integral membrane protein that facilitates nascent HDL particle assembly. Past studies attributed the inverse relationship between plasma HDL and triglyceride to intravascular lipid exchange and catabolic events. However, recent studies also suggest that hepatic signaling and lipid mobilization and secretion may explain how HDL affects plasma triglyceride concentrations. Hepatocyte-specific ABCA1 knockout mice have markedly reduced plasma HDL and a two-fold increase in triglyceride due to failure to assemble nascent HDL particles by hepatocytes, causing increased catabolism of HDL apolipoprotein A-I and increased hepatic production of triglyceride-enriched VLDL. In-vitro studies suggest that nascent HDL particles may induce signaling to decrease triglyceride secretion. Inhibition of microRNA 33 expression in nonhuman primates augments hepatic ABCA1, genes involved in fatty acid oxidation, and decreases expression of lipogenic genes, causing increased plasma HDL and decreased triglyceride levels. New evidence suggests potential mechanisms by which hepatic ABCA1-mediated nascent HDL formation regulates VLDL-triglyceride production and contributes to the inverse relationship between plasma HDL and triglyceride.

  1. ABC Transporters and the Alzheimer’s Disease Enigma

    Directory of Open Access Journals (Sweden)

    Andrea eWolf

    2012-06-01

    Full Text Available Alzheimer’s disease (AD is considered the disease of the 21st century. With a 10-fold increase in global incidence over the past 100 years, AD is now reaching epidemic proportions and by all projections, AD patient numbers will continue to rise. Despite intense research efforts, AD remains a mystery and effective therapies are still unavailable. This represents an unmet need resulting in clinical, social, and economic problems.Over the last decade, a new AD research focus has emerged: ATP-binding cassette (ABC transporters. In this article, we provide an overview of the ABC transporters ABCA1, ABCA2, P-glycoprotein (ABCB1, Mrp1 (ABCC1 and BCRP (ABCG2, all of which are expressed in the brain and have been implicated in AD. We summarize recent findings on the role of these five transporters in AD, and discuss their potential to serve as therapeutic targets.

  2. Transportomics: screening for substrates of ABC transporters in body fluids using vesicular transport assays.

    NARCIS (Netherlands)

    Krumpochova, P; Sapthu, S.; Brouwers, J.F.H.M.; de Haas, M.; de Vos, R.; Borst, P.; van de Wetering, K.

    2013-01-01

    ABSTRACT The ATP-binding cassette (ABC) genes encode the largest family of transmembrane proteins. ABC transporters translocate a wide variety of substrates across membranes, but their physiological function is often incompletely understood. We describe a new method to study the substrate spectrum

  3. [Peroxisomal ABC transporters and X-linked adrenoleukodystrophy].

    Science.gov (United States)

    Geillon, Flore; Trompier, Doriane; Gondcaille, Catherine; Lizard, Gérard; Savary, Stéphane

    2012-12-01

    X-linked adrenoleukodystrophy (X-ALD) is a complex neurodegenerative disease associated with mutations in the ABCD1 gene, which encodes for a peroxisomal ABC transporter. Thanks to the efforts of the ELA foundation and to the recent successes of gene therapy published in Science in 2009, X-ALD is better known but still remains poorly understood. The exact role of ABCD1 and its homologs, as well as the exact link between the biochemical and metabolic peroxisomal defects and the clinical symptoms of the disease remain to be elucidated. This review summarizes the knowledge concerning the subfamily D of the ABC transporter family and concerning X-ALD, the most frequent peroxisomal disorder. © 2012 médecine/sciences – Inserm / SRMS.

  4. ABC and MFS transporters from Botrytis cinerea involved in sensitivity to fungicides and natural toxic compounds

    NARCIS (Netherlands)

    Hayashi, K.

    2003-01-01

    ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporters are two major classes of proteins involved in drug resistance. ABC transporter proteins are primary transporters that use the energy generated by ATP hydrolysis to transport drugs over membranes, while MFS transport

  5. A multidrug ABC transporter with a taste for salt.

    Directory of Open Access Journals (Sweden)

    Saroj Velamakanni

    2009-07-01

    Full Text Available LmrA is a multidrug ATP-binding cassette (ABC transporter from Lactococcus lactis with no known physiological substrate, which can transport a wide range of chemotherapeutic agents and toxins from the cell. The protein can functionally replace the human homologue ABCB1 (also termed multidrug resistance P-glycoprotein MDR1 in lung fibroblast cells. Even though LmrA mediates ATP-dependent transport, it can use the proton-motive force to transport substrates, such as ethidium bromide, across the membrane by a reversible, H(+-dependent, secondary-active transport reaction. The mechanism and physiological context of this reaction are not known.We examined ion transport by LmrA in electrophysiological experiments and in transport studies using radioactive ions and fluorescent ion-selective probes. Here we show that LmrA itself can transport NaCl by a similar secondary-active mechanism as observed for ethidium bromide, by mediating apparent H(+-Na(+-Cl(- symport. Remarkably, LmrA activity significantly enhances survival of high-salt adapted lactococcal cells during ionic downshift.The observations on H(+-Na(+-Cl(- co-transport substantiate earlier suggestions of H(+-coupled transport by LmrA, and indicate a novel link between the activity of LmrA and salt stress. Our findings demonstrate the relevance of investigations into the bioenergetics of substrate translocation by ABC transporters for our understanding of fundamental mechanisms in this superfamily. This study represents the first use of electrophysiological techniques to analyze substrate transport by a purified multidrug transporter.

  6. Functional expression and characterization of plant ABC transporters in Xenopus laevis oocytes for transport engineering purposes

    DEFF Research Database (Denmark)

    Xu, Deyang; Veres, Dorottya; Belew, Zeinu Mussa

    2016-01-01

    Transport engineering in bioengineering is aimed at efficient export of the final product to reduce toxicity and feedback inhibition and to increase yield. The ATP-binding cassette (ABC) transporters with their highly diverse substrate specificity and role in cellular efflux are potentially...... suitable in transport engineering approaches, although their size and high number of introns make them notoriously difficult to clone. Here, we report a novel in planta “exon engineering” strategy for cloning of full-length coding sequence of ABC transporters followed by methods for biochemical...... provided will hopefully contribute to more successful transport engineering in synthetic biology....

  7. Obstacles to Brain Tumor Therapy: Key ABC Transporters

    Directory of Open Access Journals (Sweden)

    Juwina Wijaya

    2017-11-01

    Full Text Available The delivery of cancer chemotherapy to treat brain tumors remains a challenge, in part, because of the inherent biological barrier, the blood–brain barrier. While its presence and role as a protector of the normal brain parenchyma has been acknowledged for decades, it is only recently that the important transporter components, expressed in the tightly knit capillary endothelial cells, have been deciphered. These transporters are ATP-binding cassette (ABC transporters and, so far, the major clinically important ones that functionally contribute to the blood–brain barrier are ABCG2 and ABCB1. A further limitation to cancer therapy of brain tumors or brain metastases is the blood–tumor barrier, where tumors erect a barrier of transporters that further impede drug entry. The expression and regulation of these two transporters at these barriers, as well as tumor derived alteration in expression and/or mutation, are likely obstacles to effective therapy.

  8. Second-order nonlinear optical metamaterials: ABC-type nanolaminates

    International Nuclear Information System (INIS)

    Alloatti, L.; Kieninger, C.; Lauermann, M.; Köhnle, K.; Froelich, A.; Wegener, M.; Frenzel, T.; Freude, W.; Leuthold, J.; Koos, C.

    2015-01-01

    We demonstrate a concept for second-order nonlinear metamaterials that can be obtained from non-metallic centrosymmetric constituents with inherently low optical absorption. The concept is based on iterative atomic-layer deposition of three different materials, A = Al 2 O 3 , B = TiO 2 , and C = HfO 2 . The centrosymmetry of the resulting ABC stack is broken since the ABC and the inverted CBA sequences are not equivalent—a necessary condition for non-zero second-order nonlinearity. In our experiments, we find that the bulk second-order nonlinear susceptibility depends on the density of interfaces, leading to a nonlinear susceptibility of 0.26 pm/V at a wavelength of 800 nm. ABC-type nanolaminates can be deposited on virtually any substrate and offer a promising route towards engineering of second-order optical nonlinearities at both infrared and visible wavelengths

  9. Describing the role of Drosophila melanogaster ABC transporters in insecticide biology using CRISPR-Cas9 knockouts.

    Science.gov (United States)

    Denecke, Shane; Fusetto, Roberto; Batterham, Philip

    2017-12-01

    ABC transporters have a well-established role in drug resistance, effluxing xenobiotics from cells and tissues within the organism. More recently, research has been dedicated to understanding the role insect ABC transporters play in insecticide toxicity, but progress in understanding the contribution of specific transporters has been hampered by the lack of functional genetic tools. Here, we report knockouts of three Drosophila melanogaster ABC transporter genes, Mdr49, Mdr50, and Mdr65, that are homologous to the well-studied mammalian ABCB1 (P-glycoprotein). Each knockout mutant was created in the same wild type background and tested against a panel of insecticides representing different chemical classes. Mdr65 knockouts were more susceptible to all neuroactive insecticides tested, but Mdr49 and Mdr50 knockouts showed increased susceptibility or resistance depending on the insecticide used. Mdr65 was chosen for further analysis. Calculation of LC 50 values for the Mdr65 knockout allowed the substrate specificity of this transporter to be examined. No obvious distinguishing structural features were shared among MDR65 substrates. A role for Mdr65 in insecticide transport was confirmed by testing the capacity of the knockout to synergize with the ABC inhibitor verapamil and by measuring the levels of insecticide retained in the body of knockout flies. These data unambiguously establish the influence of ABC transporters on the capacity of wild type D. melanogaster to tolerate insecticide exposure and suggest that both tissue and substrate specificity underpin this capacity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. ABC Transporter for Corrinoids in Halobacterium sp. Strain NRC-1†

    OpenAIRE

    Woodson, Jesse D.; Reynolds, April A.; Escalante-Semerena, Jorge C.

    2005-01-01

    We report evidence for the existence of a putative ABC transporter for corrinoid utilization in the extremely halophilic archaeon Halobacterium sp. strain NRC-1. Results from genetic and nutritional analyses of Halobacterium showed that mutants with lesions in open reading frames (ORFs) Vng1370G, Vng1371Gm, and Vng1369G required a 105-fold higher concentration of cobalamin for growth than the wild-type or parent strain. The data support the conclusion that these ORFs encode orthologs of the b...

  11. ABC transporters from Aspergillus nidulans are involved in protection against cytotoxic agents and antibiotic production

    NARCIS (Netherlands)

    Andrade, A.C.; Nistelrooy, van J.G.M.; Peery, R.B.; Skatrud, P.L.; Waard, de M.A.

    2000-01-01

    This paper describes the characterization of atrC and atrD (ABC transporters C and D), two novel ABC transporter-encoding genes from the filamentous fungus Aspergillus nidulans, and provides evidence for the involvement of atrD in multidrug transport and antibiotic production. BLAST analysis of the

  12. The ABC gene family in arthropods: comparative genomics and role in insecticide transport and resistance.

    Science.gov (United States)

    Dermauw, Wannes; Van Leeuwen, Thomas

    2014-02-01

    About a 100 years ago, the Drosophila white mutant marked the birth of Drosophila genetics. The white gene turned out to encode the first well studied ABC transporter in arthropods. The ABC gene family is now recognized as one of the largest transporter families in all kingdoms of life. The majority of ABC proteins function as primary-active transporters that bind and hydrolyze ATP while transporting a large diversity of substrates across lipid membranes. Although extremely well studied in vertebrates for their role in drug resistance, less is known about the role of this family in the transport of endogenous and exogenous substances in arthropods. The ABC families of five insect species, a crustacean and a chelicerate have been annotated in some detail. We conducted a thorough phylogenetic analysis of the seven arthropod and human ABC protein subfamilies, to infer orthologous relationships that might suggest conserved function. Most orthologous relationships were found in the ABCB half transporter, ABCD, ABCE and ABCF subfamilies, but specific expansions within species and lineages are frequently observed and discussed. We next surveyed the role of ABC transporters in the transport of xenobiotics/plant allelochemicals and their involvement in insecticide resistance. The involvement of ABC transporters in xenobiotic resistance in arthropods is historically not well documented, but an increasing number of studies using unbiased differential gene expression analysis now points to their importance. We give an overview of methods that can be used to link ABC transporters to resistance. ABC proteins have also recently been implicated in the mode of action and resistance to Bt toxins in Lepidoptera. Given the enormous interest in Bt toxicology in transgenic crops, such findings will provide an impetus to further reveal the role of ABC transporters in arthropods. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Transmembrane Domain Single-Nucleotide Polymorphisms Impair Expression and Transport Activity of ABC Transporter ABCG2

    NARCIS (Netherlands)

    Sjostedt, N.; Heuvel, J.J.M.W. van den; Koenderink, J.B.; Kidron, H.

    2017-01-01

    PURPOSE: To study the function and expression of nine naturally occurring single-nucleotide polymorphisms (G406R, F431L, S441N, P480L, F489L, M515R, L525R, A528T and T542A) that are predicted to reside in the transmembrane regions of the ABC transporter ABCG2. METHODS: The transport activity of the

  14. A Critical View on ABC Transporters and Their Interacting Partners in Auxin Transport.

    Science.gov (United States)

    Geisler, Markus; Aryal, Bibek; di Donato, Martin; Hao, Pengchao

    2017-10-01

    Different subclasses of ATP-binding cassette (ABC) transporters have been implicated in the transport of native variants of the phytohormone auxin. Here, the putative, individual roles of key members belonging to the ABCB, ABCD and ABCG families, respectively, are highlighted and the knowledge of their assumed expression and transport routes is reviewed and compared with their mutant phenotypes. Protein-protein interactions between ABC transporters and regulatory components during auxin transport are summarized and their importance is critically discussed. There is a focus on the functional interaction between members of the ABCB family and the FKBP42, TWISTED DWARF1, acting as a chaperone during plasma membrane trafficking of ABCBs. Further, the mode and relevance of functional ABCB-PIN interactions is diagnostically re-evaluated. A new nomenclature describing precisely the most likely ABCB-PIN interaction scenarios is suggested. Finally, available tools for the detection and prediction of ABC transporter interactomes are summarized and the potential of future ABC transporter interactome maps is highlighted. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  15. Transmembrane Domain Single-Nucleotide Polymorphisms Impair Expression and Transport Activity of ABC Transporter ABCG2.

    Science.gov (United States)

    Sjöstedt, Noora; van den Heuvel, Jeroen J M W; Koenderink, Jan B; Kidron, Heidi

    2017-08-01

    To study the function and expression of nine naturally occurring single-nucleotide polymorphisms (G406R, F431L, S441N, P480L, F489L, M515R, L525R, A528T and T542A) that are predicted to reside in the transmembrane regions of the ABC transporter ABCG2. The transport activity of the variants was tested in inside-out membrane vesicles from Sf9 insect and human derived HEK293 cells overexpressing ABCG2. Lucifer Yellow and estrone sulfate were used as probe substrates of activity. The expression levels and cellular localization of the variants was compared to the wild-type ABCG2 by western blotting and immunofluorescence microscopy. All studied variants of ABCG2 displayed markedly decreased transport in both Sf9-ABCG2 and HEK293-ABCG2 vesicles. Impaired transport could be explained for some variants by altered expression levels and cellular localization. Moreover, the destructive effect on transport activity of variants G406R, P480L, M515R and T542A is, to our knowledge, reported for the first time. These results indicate that the transmembrane region of ABCG2 is sensitive to amino acid substitution and that patients harboring these ABCG2 variant forms could suffer from unexpected pharmacokinetic events of ABCG2 substrate drugs or have an increased risk for diseases such as gout where ABCG2 is implicated.

  16. Transport mechanism of acyl-CoA into peroxisomes by a peroxisomal ABC transporter, ABCD1

    OpenAIRE

    Agustina, Rina

    2016-01-01

    Transport mechanism of acyl-CoA into peroxisomes by a peroxisomal ABC protein, ABCD1 ABCD1, belonging to the ABC protein subfamily D, is aperoxisomal membrane protein and involves in the transport of very long chain fatty acid (VLCFA)-CoA into peroxisomes. Its mutation causes X-linked adrenoleukodystophy; an inborn error of peroxisomal VLCFA ??-oxidation. It has been reported that COMATOSE, a homolog of human ABCD1 in plant possess acyl-CoA thioesterase (ACOT) activity and t...

  17. Diversity of ABC transporter genes across the plant kingdom and their potential utility in biotechnology.

    Science.gov (United States)

    Lane, Thomas S; Rempe, Caroline S; Davitt, Jack; Staton, Margaret E; Peng, Yanhui; Soltis, Douglas Edward; Melkonian, Michael; Deyholos, Michael; Leebens-Mack, James H; Chase, Mark; Rothfels, Carl J; Stevenson, Dennis; Graham, Sean W; Yu, Jun; Liu, Tao; Pires, J Chris; Edger, Patrick P; Zhang, Yong; Xie, Yinlong; Zhu, Ying; Carpenter, Eric; Wong, Gane Ka-Shu; Stewart, C Neal

    2016-05-31

    The ATP-binding cassette (ABC) transporter gene superfamily is ubiquitous among extant organisms and prominently represented in plants. ABC transporters act to transport compounds across cellular membranes and are involved in a diverse range of biological processes. Thus, the applicability to biotechnology is vast, including cancer resistance in humans, drug resistance among vertebrates, and herbicide and other xenobiotic resistance in plants. In addition, plants appear to harbor the highest diversity of ABC transporter genes compared with any other group of organisms. This study applied transcriptome analysis to survey the kingdom-wide ABC transporter diversity in plants and suggest biotechnology applications of this diversity. We utilized sequence similarity-based informatics techniques to infer the identity of ABC transporter gene candidates from 1295 phylogenetically-diverse plant transcriptomes. A total of 97,149 putative (approximately 25 % were full-length) ABC transporter gene members were identified; each RNA-Seq library (plant sample) had 88 ± 30 gene members. As expected, simpler organisms, such as algae, had fewer unique members than vascular land plants. Differences were also noted in the richness of certain ABC transporter subfamilies. Land plants had more unique ABCB, ABCC, and ABCG transporter gene members on average (p plant groups (p plant groups. An increase in the number of gene family members present in the ABCB, ABCC, and ABCD transporter subfamilies may indicate an expansion of the ABC transporter superfamily among green land plants, which include all crop species. The striking difference between the number of ABCA subfamily transporter gene members between ferns and other plant taxa is surprising and merits further investigation. Discussed is the potential exploitation of ABC transporters in plant biotechnology, with an emphasis on crops.

  18. Changes in metabolism affect expression of ABC transporters through ERK5 and depending on p53 status.

    Science.gov (United States)

    Belkahla, Sana; Haq Khan, Abrar Ul; Gitenay, Delphine; Alexia, Catherine; Gondeau, Claire; Vo, Dang-Nghiem; Orecchioni, Stefania; Talarico, Giovanna; Bertolini, Francesco; Cartron, Guillaume; Hernandez, Javier; Daujat-Chavanieu, Martine; Allende-Vega, Nerea; Gonzalez, Martin Villalba

    2018-01-02

    Changes in metabolism require the efflux and influx of a diverse variety of metabolites. The ABC superfamily of transporters regulates the exchange of hundreds of substrates through the impermeable cell membrane. We show here that a metabolic switch to oxidative phosphorylation (OXPHOS), either by treating cells with dichloroacetate (DCA) or by changing the available substrates, reduced expression of ABCB1, ABCC1, ABCC5 and ABCG2 in wild-type p53-expressing cells. This metabolic change reduced histone changes associated to active promoters. Notably, DCA also inhibited expression of these genes in two animal models in vivo . In contrast, OXPHOS increased the expression of the same transporters in mutated (mut) or null p53-expressing cells. ABC transporters control the export of drugs from cancer cells and render tumors resistant to chemotherapy, playing an important role in multiple drug resistance (MDR). Wtp53 cells forced to perform OXPHOS showed impaired drug clearance. In contrast mutp53 cells increased drug clearance when performing OXPHOS. ABC transporter promoters contain binding sites for the transcription factors MEF2, NRF1 and NRF2 that are targets of the MAPK ERK5. OXPHOS induced expression of the MAPK ERK5. Decreasing ERK5 levels in wtp53 cells increased ABC expression whereas it inhibited expression in mutp53 cells. Our results showed that the ERK5/MEF2 pathway controlled ABC expression depending on p53 status.

  19. Second-order nonlinear optical metamaterials: ABC-type nanolaminates

    Energy Technology Data Exchange (ETDEWEB)

    Alloatti, L., E-mail: alloatti@mit.edu; Kieninger, C.; Lauermann, M.; Köhnle, K. [Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Froelich, A.; Wegener, M. [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76021 Karlsruhe (Germany); Frenzel, T. [Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Freude, W. [Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Institute for Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); Leuthold, J.; Koos, C., E-mail: christian.koos@kit.edu [Institute of Photonics and Quantum Electronics (IPQ), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Institute for Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany)

    2015-09-21

    We demonstrate a concept for second-order nonlinear metamaterials that can be obtained from non-metallic centrosymmetric constituents with inherently low optical absorption. The concept is based on iterative atomic-layer deposition of three different materials, A = Al{sub 2}O{sub 3}, B = TiO{sub 2}, and C = HfO{sub 2}. The centrosymmetry of the resulting ABC stack is broken since the ABC and the inverted CBA sequences are not equivalent—a necessary condition for non-zero second-order nonlinearity. In our experiments, we find that the bulk second-order nonlinear susceptibility depends on the density of interfaces, leading to a nonlinear susceptibility of 0.26 pm/V at a wavelength of 800 nm. ABC-type nanolaminates can be deposited on virtually any substrate and offer a promising route towards engineering of second-order optical nonlinearities at both infrared and visible wavelengths.

  20. Hematopoietic stem cells exhibit a specific ABC transporter gene expression profile clearly distinct from other stem cells.

    NARCIS (Netherlands)

    Tang, L.; Bergevoet, S.M.; Gilissen, C.F.H.A.; Witte, T.J.M. de; Jansen, J.H.; Reijden, B.A. van der; Raymakers, R.A.P.

    2010-01-01

    BACKGROUND: ATP-binding cassette (ABC) transporters protect cells against unrelated (toxic) substances by pumping them across cell membranes. Earlier we showed that many ABC transporters are highly expressed in hematopoietic stem cells (HSCs) compared to more committed progenitor cells. The ABC

  1. Current Understanding of Interactions between Nanoparticles and ABC Transporters in Cancer Cells.

    Science.gov (United States)

    Yin, Jian; Deng, Xudong; Zhang, Jie; Lin, Jun

    2018-03-14

    Adenosine triphosphate-binding cassette (ABC) transporters-mediated multidrug resistance (MDR) remains as a obstacle for effective cancer therapy. Nanoparticles (NPs)-based delivery systems are promising to overcome MDR, but only a few of them have been accepted for clinical treatment, due to characteristics such as insufficient transportation and potential toxicity. In this respect, mounting attention has been attracted towards interactions between NPs and ABC transporters, which hold a key role in the treatment of multidrug-resistant cancer and NP toxicity. In this review article, current knowledge on the involvement of ABC transporters in MDR and their inhibitors is provided. More importantly, recent literatures about the interactions between NPs and ABC transporters are summarized here. Organic and inorganic NPs inhibit the function of ABC transporters based on distinct mechanisms. The effects of organic NPs are caused by several excipients like surfactants, polymers, lipids and cyclodextrin, whereas inorganic NPs act as substrates of ABC transporters and competitively inhibit the efflux of drugs. Based on these interesting phenomena, a more thorough understanding of the specific mechanisms is necessary and essential in the hope to develop more efficient NPs to overcome MDR and decrease environmental toxicity of NPs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  2. The ABC of Biofilm Drug Tolerance: the MerR-Like Regulator BrlR Is an Activator of ABC Transport Systems, with PA1874-77 Contributing to the Tolerance of Pseudomonas aeruginosa Biofilms to Tobramycin.

    Science.gov (United States)

    Poudyal, Bandita; Sauer, Karin

    2018-02-01

    A hallmark of biofilms is their tolerance to killing by antimicrobial agents. In Pseudomonas aeruginosa , biofilm drug tolerance requires the c-di-GMP-responsive MerR transcriptional regulator BrlR. However, the mechanism by which BrlR mediates biofilm drug tolerance has not been elucidated. Here, we demonstrate that BrlR activates the expression of at least 7 ABC transport systems, including the PA1874-PA1875-PA1876-PA1877 (PA1874-77) operon, with chromatin immunoprecipitation and DNA binding assays confirming BrlR binding to the promoter region of PA1874-77. Insertional inactivation of the 7 ABC transport systems rendered P. aeruginosa PAO1 biofilms susceptible to tobramycin or norfloxacin. Susceptibility was linked to drug accumulation, with BrlR contributing to norfloxacin accumulation in a manner dependent on multidrug efflux pumps and the PA1874-77 ABC transport system. Inactivation of the respective ABC transport system, furthermore, eliminated the recalcitrance of biofilms to killing by tobramycin but not norfloxacin, indicating that drug accumulation is not linked to biofilm drug tolerance. Our findings indicate for the first time that BrlR, a MerR-type transcriptional activator, activates genes encoding several ABC transport systems, in addition to multiple multidrug efflux pump genes. Moreover, our data confirm a BrlR target contributing to drug tolerance, likely countering the prevailing dogma that biofilm tolerance arises from a multiplicity of factors. Copyright © 2018 American Society for Microbiology.

  3. A putative ABC transporter is involved in negative regulation of biofilm formation by Listeria monocytogenes

    DEFF Research Database (Denmark)

    Zhu, Xinna; Long, Fei; Chen, Yonghui

    2008-01-01

    with enhanced ability of biofilm-formation generated via transposon Tn917 mutagenesis of L. monocytogenes 4b G. In this mutant, a Tn917 insertion has disrupted the coding region of the gene encoding a putative ATP binding cassette (ABC) transporter permease identical to Lmof2365_1771 (a putative ABC...... regulation of biofilm formation by L. monocytogenes 4b G. The immediate gene upstream of lm.G_1771 encoded an ATP-binding protein. Bioinformatics analysis suggested that these two genes were organized into an operon and that their proteins formed an export ABC transporter. Here, we report...... the characterization of the mutant and identification of a novel ABC transporter that functions in negative regulation of biofilm formation in L. monocytogenes....

  4. The multidrug-resistant phenotype associated with overexpression of the new ABC half-transporter, MXR (ABCG2)

    DEFF Research Database (Denmark)

    Litman, Thomas; Brangi, M; Hudson, E

    2000-01-01

    Mechanisms of drug resistance other than P-glycoprotein are of increasing interest as the list of newly identified members of the ABC transport family has grown. We sought to characterize the phenotype of the newly discovered ABC transporter encoded by the mitoxantrone resistance gene, MXR, also...... that the ABC half-transporter, MXR, is a potent, new mechanism for conferring multiple drug resistance. Definition of its mechanism of transport and its role in clinical oncology is required....

  5. Multi-Drug Resistance ABC Transporter Inhibition Enhances Murine Ventral Prostate Stem/Progenitor Cell Differentiation.

    Science.gov (United States)

    Samant, Mugdha D; Jackson, Courtney M; Felix, Carina L; Jones, Anthony J; Goodrich, David W; Foster, Barbara A; Huss, Wendy J

    2015-05-15

    Multi-drug resistance (MDR)-ATP binding cassette (ABC) transporters, ABCB1, ABCC1, and ABCG2 participate in the efflux of steroid hormones, estrogens, and androgens, which regulate prostate development and differentiation. The role of MDR-ABC efflux transporters in prostate epithelial proliferation and differentiation remains unclear. We hypothesized that MDR-ABC transporters regulate prostate differentiation and epithelium regeneration. Prostate epithelial differentiation was studied using histology, sphere formation assay, and prostate regeneration induced by cycles of repeated androgen withdrawal and replacement. Embryonic deletion of Abcg2 resulted in a decreased number of luminal cells in the prostate and increased sphere formation efficiency, indicating an imbalance in the prostate epithelial differentiation pattern. Decreased luminal cell number in the Abcg2 null prostate implies reduced differentiation. Enhanced sphere formation efficiency in Abcg2 null prostate cells implies activation of the stem/progenitor cells. Prostate regeneration was associated with profound activation of the stem/progenitor cells, indicating the role of Abcg2 in maintaining stem/progenitor cell pool. Since embryonic deletion of Abcg2 may result in compensation by other ABC transporters, pharmacological inhibition of MDR-ABC efflux was performed. Pharmacological inhibition of MDR-ABC efflux enhanced prostate epithelial differentiation in sphere culture and during prostate regeneration. In conclusion, Abcg2 deletion leads to activation of the stem/progenitor cells and enhances differentiating divisions; and pharmacological inhibition of MDR-ABC efflux leads to epithelial differentiation. Our study demonstrates for the first time that MDR-ABC efflux transporter inhibition results in enhanced prostate epithelial cell differentiation.

  6. Frequent down-regulation of ABC transporter genes in prostate cancer

    International Nuclear Information System (INIS)

    Demidenko, Rita; Razanauskas, Deividas; Daniunaite, Kristina; Lazutka, Juozas Rimantas; Jankevicius, Feliksas; Jarmalaite, Sonata

    2015-01-01

    ATP-binding cassette (ABC) transporters are transmembrane proteins responsible for the efflux of a wide variety of substrates, including steroid metabolites, through the cellular membranes. For better characterization of the role of ABC transporters in prostate cancer (PCa) development, the profile of ABC transporter gene expression was analyzed in PCa and noncancerous prostate tissues (NPT). TaqMan Low Density Array (TLDA) human ABC transporter plates were used for the gene expression profiling in 10 PCa and 6 NPT specimens. ABCB1 transcript level was evaluated in a larger set of PCa cases (N = 78) and NPT (N = 15) by real-time PCR, the same PCa cases were assessed for the gene promoter hypermethylation by methylation-specific PCR. Expression of eight ABC transporter genes (ABCA8, ABCB1, ABCC6, ABCC9, ABCC10, ABCD2, ABCG2, and ABCG4) was significantly down-regulated in PCa as compared to NPT, and only two genes (ABCC4 and ABCG1) were up-regulated. Down-regulation of ABC transporter genes was prevalent in the TMPRSS2-ERG-negative cases. A detailed analysis of ABCB1 expression confirmed TLDA results: a reduced level of the transcript was identified in PCa in comparison to NPT (p = 0.048). Moreover, the TMPRSS2-ERG-negative PCa cases showed significantly lower expression of ABCB1 in comparison to NPT (p = 0.003) or the fusion-positive tumors (p = 0.002). Promoter methylation of ABCB1 predominantly occurred in PCa and was rarely detected in NPT (p < 0.001). The study suggests frequent down-regulation of the ABC transporter genes in PCa, especially in the TMPRSS2-ERG-negative tumors. The online version of this article (doi:10.1186/s12885-015-1689-8) contains supplementary material, which is available to authorized users

  7. Identification of ABC transporter genes of Fusarium graminearum with roles in azole tolerance and/or virulence.

    Directory of Open Access Journals (Sweden)

    Ghada Abou Ammar

    Full Text Available Fusarium graminearum is a plant pathogen infecting several important cereals, resulting in substantial yield losses and mycotoxin contamination of the grain. Triazole fungicides are used to control diseases caused by this fungus on a worldwide scale. Our previous microarray study indicated that 15 ABC transporter genes were transcriptionally upregulated in response to tebuconazole treatment. Here, we deleted four ABC transporter genes in two genetic backgrounds of F. graminearum representing the DON (deoxynivalenol and the NIV (nivalenol trichothecene chemotypes. Deletion of FgABC3 and FgABC4 belonging to group I of ABC-G and to group V of ABC-C subfamilies of ABC transporters, respectively, considerably increased the sensitivity to the class I sterol biosynthesis inhibitors triazoles and fenarimol. Such effects were specific since they did not occur with any other fungicide class tested. Assessing the contribution of the four ABC transporters to virulence of F. graminearum revealed that, irrespective of their chemotypes, deletion mutants of FgABC1 (ABC-C subfamily group V and FgABC3 were impeded in virulence on wheat, barley and maize. Phylogenetic context and analyses of mycotoxin production suggests that FgABC3 may encode a transporter protecting the fungus from host-derived antifungal molecules. In contrast, FgABC1 may encode a transporter responsible for the secretion of fungal secondary metabolites alleviating defence of the host. Our results show that ABC transporters play important and diverse roles in both fungicide resistance and pathogenesis of F. graminearum.

  8. The AbcA Transporter of Staphylococcus aureus Affects Cell Autolysis

    Science.gov (United States)

    Schrader-Fischer, Gesine; Berger-Bächi, Brigitte

    2001-01-01

    Increased production of penicillin-binding protein PBP 4 is known to increase peptidoglycan cross-linking and contributes to methicillin resistance in Staphylococcus aureus. The pbp4 gene shares a 400-nucleotide intercistronic region with the divergently transcribed abcA gene, encoding an ATP-binding cassette transporter of unknown function. Our study revealed that methicillin stimulated abcA transcription but had no effects on pbp4 transcription. Analysis of abcA expression in mutants defective for global regulators showed that abcA is under the control of agr. Insertional inactivation of abcA by an erythromycin resistance determinant did not influence pbp4 transcription, nor did it alter resistance to methicillin and other cell wall-directed antibiotics. However, abcA mutants showed spontaneous partial lysis on plates containing subinhibitory concentrations of methicillin due to increased spontaneous autolysis. Since the autolytic zymograms of cell extracts were identical in mutants and parental strains, we postulate an indirect role of AbcA in control of autolytic activities and in protection of the cells against methicillin. PMID:11158733

  9. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana

    OpenAIRE

    Stefanato, Francesca L.; Abou-Mansour, Eliane; Buchala, Antony; Kretschmer, Matthias; Mosbach, Andreas; Hahn, Matthias; Bochet, Christian G.; Métraux, Jean-Pierre; Schoonbeek, Henk-jan

    2009-01-01

    Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mut...

  10. ABC transporters as multidrug resistance mechanisms and the development of chemosensitizers for their reversal

    Directory of Open Access Journals (Sweden)

    Choi Cheol-Hee

    2005-10-01

    Full Text Available Abstract One of the major problems related with anticancer chemotherapy is resistance against anticancer drugs. The ATP-binding cassette (ABC transporters are a family of transporter proteins that are responsible for drug resistance and a low bioavailability of drugs by pumping a variety of drugs out cells at the expense of ATP hydrolysis. One strategy for reversal of the resistance of tumor cells expressing ABC transporters is combined use of anticancer drugs with chemosensitizers. In this review, the physiological functions and structures of ABC transporters, and the development of chemosensitizers are described focusing on well-known proteins including P-glycoprotein, multidrug resistance associated protein, and breast cancer resistance protein.

  11. Glycolysis inhibition inactivates ABC transporters to restore drug sensitivity in malignant cells.

    Directory of Open Access Journals (Sweden)

    Ayako Nakano

    Full Text Available Cancer cells eventually acquire drug resistance largely via the aberrant expression of ATP-binding cassette (ABC transporters, ATP-dependent efflux pumps. Because cancer cells produce ATP mostly through glycolysis, in the present study we explored the effects of inhibiting glycolysis on the ABC transporter function and drug sensitivity of malignant cells. Inhibition of glycolysis by 3-bromopyruvate (3BrPA suppressed ATP production in malignant cells, and restored the retention of daunorubicin or mitoxantrone in ABC transporter-expressing, RPMI8226 (ABCG2, KG-1 (ABCB1 and HepG2 cells (ABCB1 and ABCG2. Interestingly, although side population (SP cells isolated from RPMI8226 cells exhibited higher levels of glycolysis with an increased expression of genes involved in the glycolytic pathway, 3BrPA abolished Hoechst 33342 exclusion in SP cells. 3BrPA also disrupted clonogenic capacity in malignant cell lines including RPMI8226, KG-1, and HepG2. Furthermore, 3BrPA restored cytotoxic effects of daunorubicin and doxorubicin on KG-1 and RPMI8226 cells, and markedly suppressed subcutaneous tumor growth in combination with doxorubicin in RPMI8226-implanted mice. These results collectively suggest that the inhibition of glycolysis is able to overcome drug resistance in ABC transporter-expressing malignant cells through the inactivation of ABC transporters and impairment of SP cells with enhanced glycolysis as well as clonogenic cells.

  12. The therapeutic potential of targeting ABC transporters to combat multi-drug resistance.

    Science.gov (United States)

    Bugde, Piyush; Biswas, Riya; Merien, Fabrice; Lu, Jun; Liu, Dong-Xu; Chen, Mingwei; Zhou, Shufeng; Li, Yan

    2017-05-01

    Most disseminated cancers remain fatal despite the availability of a variety of conventional and novel treatments including surgery, chemotherapy, radiotherapy, immunotherapy, and biologically targeted therapy. A major factor responsible for the failure of chemotherapy in the treatment of cancer is the development of multidrug resistance (MDR). The overexpression of various ABC transporters in cancer cells can efficiently remove the anticancer drug from the cell, thus causing the drug to lose its effect. Areas covered: In this review, we summarised the ongoing research related to the mechanism, function, and regulation of ABC transporters. We integrated our current knowledge at different levels from molecular biology to clinical trials. We also discussed potential therapeutic strategies of targeting ABC transporters to reverse MDR in cancer cells. Expert opinion: Involvement of various ABC transporters to cancer MDR lays the foundation for developing tailored therapies that can overcome MDR. An ideal MDR reversal agent should have broad-spectrum ABC-transporter inhibitory activity, be potent, have good pharmacokinetics, have no trans-stimulation effects, and have low or no toxicity. Alternatively, nanotechnology-based drug delivery systems containing both the cytotoxic drug and reversing agent may represent a useful approach to reversing MDR with minimal off-target toxicity.

  13. Structure of the MacAB-TolC ABC-type tripartite multidrug efflux pump

    Science.gov (United States)

    Llabrés, Salomé; Neuberger, Arthur; Blaza, James N.; Bai, Xiao-chen; Okada, Ui; Murakami, Satoshi; van Veen, Hendrik W.; Zachariae, Ulrich; Scheres, Sjors H.W.; Luisi, Ben F.

    2017-01-01

    The MacA-MacB-TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain (TMD) with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism. PMID:28504659

  14. Genome-wide analysis of ATP-binding cassette (ABC) transporters in the sweetpotato whitefly, Bemisia tabaci.

    Science.gov (United States)

    Tian, Lixia; Song, Tianxue; He, Rongjun; Zeng, Yang; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Zhou, Xuguo; Zhang, Youjun

    2017-04-26

    ABC transporter superfamily is one of the largest and ubiquitous groups of proteins. Because of their role in detoxification, insect ABC transporters have gained more attention in recent years. In this study, we annotated ABC transporters from a newly sequenced sweetpotato whitefly genome. Bemisia tabaci Q biotype is an emerging global invasive species that has caused extensive damages to field crops as well as ornamental plants. A total of 55 ABC transporters containing all eight described subfamilies (A to H) were identified in the B. tabaci Q genome, including 8 ABCAs, 3 ABCBs, 6 ABCCs, 2 ABCDs, 1 ABCE, 3 ABCFs, 23 ABCGs and 9 ABCHs. In comparison to other species, subfamilies G and H in both phloem- and blood-sucking arthropods are expanded. The temporal expression profiles of these 55 ABC transporters throughout B. tabaci developmental stages and their responses to imidacloprid, a neonicotinoid insecticide, were investigated using RNA-seq analysis. Furthermore, the mRNA expression of 24 ABC transporters (44% of the total) representing all eight subfamilies was confirmed by the quantitative real-time PCR (RT-qPCR). Furthermore, mRNA expression levels estimated by RT-qPCR and RNA-seq analyses were significantly correlated (r = 0.684, p ABC transporters in B. tabaci. The identification of these ABC transporters, their temporal expression profiles during B. tabaci development, and their response to a neonicotinoid insecticide lay the foundation for functional genomic understanding of their contribution to the invasiveness of B. tabaci.

  15. Plant ABC transporters enable many unique aspects of a terrestrial plant's lifestyle

    DEFF Research Database (Denmark)

    Hwang, Jae-Ung; Song, Won-Yong; Hong, Daewoong

    2016-01-01

    Terrestrial plants have two to four times more ATP-binding cassette (ABC) transporter genes than other organisms, including their ancestral microalgae. Recent studies found that plants harboring mutations in these transporters exhibit dramatic phenotypes, many of which are related to developmental...

  16. Transcriptome-based identification of ABC transporters in the western tarnished plant bug lygus hesperus

    Science.gov (United States)

    ATP-binding cassette (ABC) transporters are a large superfamily of proteins that mediate diverse physiological functions by coupling ATP hydrolysis with substrate transport across lipid membranes. In insects, these proteins play roles in metabolism, development, eye pigmentation, and xenobiotic cle...

  17. Functional Diversity of Tandem Substrate-Binding Domains in ABC Transporters from Pathogenic Bacteria

    NARCIS (Netherlands)

    Fulyani, Faizah; Schuurman-Wolters, Gea K.; Vujicic - Zagar, Andreja; Guskov, Albert; Slotboom, Dirk-Jan; Poolman, Bert

    2013-01-01

    The ATP-binding cassette (ABC) transporter GInPQ is an essential uptake system for amino acids in gram-positive pathogens and related nonpathogenic bacteria. The transporter has tandem substrate-binding domains (SBDs) fused to each transmembrane domain, giving rise to four SBDs per functional

  18. Molybdate transporter ModABC is important for Pseudomonas aeruginosa chronic lung infection.

    Science.gov (United States)

    Périnet, Simone; Jeukens, Julie; Kukavica-Ibrulj, Irena; Ouellet, Myriam M; Charette, Steve J; Levesque, Roger C

    2016-01-12

    Mechanisms underlying the success of Pseudomonas aeruginosa in chronic lung infection among cystic fibrosis (CF) patients are poorly defined. The modA gene was previously linked to in vivo competitiveness of P. aeruginosa by a genetic screening in the rat lung. This gene encodes a subunit of transporter ModABC, which is responsible for extracellular uptake of molybdate. This compound is essential for molybdoenzymes, including nitrate reductases. Since anaerobic growth conditions are known to occur during CF chronic lung infection, inactivation of a molybdate transporter could inhibit proliferation through the inactivation of denitrification enzymes. Hence, we performed phenotypic characterization of a modA mutant strain obtained by signature-tagged mutagenesis (STM_modA) and assessed its virulence in vivo with two host models. The STM_modA mutant was in fact defective for anaerobic growth and unable to use nitrates in the growth medium for anaerobic respiration. Bacterial growth and nitrate usage were restored when the medium was supplemented with molybdate. Most significantly, the mutant strain showed reduced virulence compared to wild-type strain PAO1 according to a competitive index in the rat model of chronic lung infection and a predation assay with Dictyostelium discoideum amoebae. As the latter took place in aerobic conditions, the in vivo impact of the mutation in modA appears to extend beyond its effect on anaerobic growth. These results support the modABC-encoded transporter as important for the pathogenesis of P. aeruginosa, and suggest that enzymatic machinery implicated in anaerobic growth during chronic lung infection in CF merits further investigation as a potential target for therapeutic intervention.

  19. The human ABC transporter pseudogene family: Evidence for transcription and gene-pseudogene interference.

    Science.gov (United States)

    Piehler, Armin P; Hellum, Marit; Wenzel, Jürgen J; Kaminski, Ellen; Haug, Kari Bente Foss; Kierulf, Peter; Kaminski, Wolfgang E

    2008-04-11

    Pseudogenes are an integral component of the human genome. Little attention, however, has so far been paid to the phenomenon that some pseudogenes are transcriptionally active. Recently, we demonstrated that the human ortholog of the rodent testis-specific ATP-binding cassette (ABC) transporter Abca17 is a ubiquitously transcribed pseudogene (ABCA17P). The aim of the present study was to establish a complete inventory of all ABC transporter pseudogenes in the human genome and to identify transcriptionally active ABC transporter pseudogenes. Moreover, we tested the hypothesis that a regulatory interdependency exists between ABC transporter pseudogenes and their parental protein coding equivalents. Systematic bioinformatic analysis revealed the existence of 22 ABC transporter pseudogenes within the human genome. We identified two clusters on chromosomes 15 and 16, respectively, which harbor almost half of all pseudogenes (n = 10). Available information from EST and mRNA databases and RT-PCR expression profiling indicate that a large portion of the ABC transporter pseudogenes (45%, n = 10) are transcriptionally active and some of them are expressed as alternative splice variants. We demonstrate that both pseudogenes of the pseudoxanthoma elasticum gene ABCC6, ABCC6P1 and ABCC6P2, are transcribed. ABCC6P1 and ABCC6 possess near-identical promoter sequences and their tissue-specific expression profiles are strikingly similar raising the possibility that they form a gene-pseudogene dual transcription unit. Intriguingly, targeted knockdown of the transcribed pseudogene ABCC6P1 resulted in a significant reduction of ABCC6 mRNA expression levels. The human genome contains a surprisingly small number of ABC transporter pseudogenes relative to other known gene families. They are unevenly distributed across the chromosomes. Importantly, a significant portion of the ABC transporter pseudogenes is transcriptionally active. The downregulation of ABCC6 mRNA levels by targeted

  20. The human ABC transporter pseudogene family: Evidence for transcription and gene-pseudogene interference

    Directory of Open Access Journals (Sweden)

    Haug Kari

    2008-04-01

    Full Text Available Abstract Background Pseudogenes are an integral component of the human genome. Little attention, however, has so far been paid to the phenomenon that some pseudogenes are transcriptionally active. Recently, we demonstrated that the human ortholog of the rodent testis-specific ATP-binding cassette (ABC transporter Abca17 is a ubiquitously transcribed pseudogene (ABCA17P. The aim of the present study was to establish a complete inventory of all ABC transporter pseudogenes in the human genome and to identify transcriptionally active ABC transporter pseudogenes. Moreover, we tested the hypothesis that a regulatory interdependency exists between ABC transporter pseudogenes and their parental protein coding equivalents. Results Systematic bioinformatic analysis revealed the existence of 22 ABC transporter pseudogenes within the human genome. We identified two clusters on chromosomes 15 and 16, respectively, which harbor almost half of all pseudogenes (n = 10. Available information from EST and mRNA databases and RT-PCR expression profiling indicate that a large portion of the ABC transporter pseudogenes (45%, n = 10 are transcriptionally active and some of them are expressed as alternative splice variants. We demonstrate that both pseudogenes of the pseudoxanthoma elasticum gene ABCC6, ABCC6P1 and ABCC6P2, are transcribed. ABCC6P1 and ABCC6 possess near-identical promoter sequences and their tissue-specific expression profiles are strikingly similar raising the possibility that they form a gene-pseudogene dual transcription unit. Intriguingly, targeted knockdown of the transcribed pseudogene ABCC6P1 resulted in a significant reduction of ABCC6 mRNA expression levels. Conclusion The human genome contains a surprisingly small number of ABC transporter pseudogenes relative to other known gene families. They are unevenly distributed across the chromosomes. Importantly, a significant portion of the ABC transporter pseudogenes is transcriptionally active

  1. Overcoming ABC transporter-mediated multidrug resistance: Molecular mechanisms and novel therapeutic drug strategies.

    Science.gov (United States)

    Li, Wen; Zhang, Han; Assaraf, Yehuda G; Zhao, Kun; Xu, Xiaojun; Xie, Jinbing; Yang, Dong-Hua; Chen, Zhe-Sheng

    2016-07-01

    Multidrug resistance is a key determinant of cancer chemotherapy failure. One of the major causes of multidrug resistance is the enhanced efflux of drugs by membrane ABC transporters. Targeting ABC transporters projects a promising approach to eliminating or suppressing drug resistance in cancer treatment. To reveal the functional mechanisms of ABC transporters in drug resistance, extensive studies have been conducted from identifying drug binding sites to elucidating structural dynamics. In this review article, we examined the recent crystal structures of ABC proteins to depict the functionally important structural elements, such as domains, conserved motifs, and critical amino acids that are involved in ATP-binding and drug efflux. We inspected the drug-binding sites on ABC proteins and the molecular mechanisms of various substrate interactions with the drug binding pocket. While our continuous battle against drug resistance is far from over, new approaches and technologies have emerged to push forward our frontier. Most recent developments in anti-MDR strategies include P-gp inhibitors, RNA-interference, nano-medicines, and delivering combination strategies. With the advent of the 'Omics' era - genomics, epigenomics, transcriptomics, proteomics, and metabolomics - these disciplines play an important role in fighting the battle against chemoresistance by further unraveling the molecular mechanisms of drug resistance and shed light on medical therapies that specifically target MDR. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. The Role of Eukaryotic and Prokaryotic ABC Transporter Family in Failure of Chemotherapy.

    Science.gov (United States)

    El-Awady, Raafat; Saleh, Ekram; Hashim, Amna; Soliman, Nehal; Dallah, Alaa; Elrasheed, Azza; Elakraa, Ghada

    2016-01-01

    Over the years chemotherapy failure has been a vital research topic as researchers have been striving to discover reasons behind it. The extensive studies carried out on chemotherapeutic agents confirm that resistance to chemotherapy is a major reason for treatment failure. "Resistance to chemotherapy," however, is a comprehensive phrase that refers to a variety of different mechanisms in which ATP-binding cassette (ABC) mediated efflux dominates. The ABC is one of the largest gene superfamily of transporters among both eukaryotes and prokaryotes; it represents a variety of genes that code for proteins, which perform countless functions, including drug efflux - a natural process that protects cells from foreign chemicals. Up to date, chemotherapy failure due to ABC drug efflux is an active research topic that continuously provides further evidence on multiple drug resistance (MDR), aiding scientists in tackling and overcoming this issue. This review focuses on drug resistance by ABC efflux transporters in human, viral, parasitic, fungal and bacterial cells and highlights the importance of the MDR permeability glycoprotein being the mutual ABC transporter among all studied organisms. Current developments and future directions to overcome this problem are also discussed.

  3. The role of ABC transporters of the blood-brain barrier in opioid tolerance development

    Directory of Open Access Journals (Sweden)

    Kamila Środa-Pomianek

    2018-02-01

    Full Text Available Opioids constitute an important group of drugs used in chronic pain treatment, e.g. cancer pain. Unfortunately, the development of the organism’s tolerance to the analgesic activity of opioids, the tendency to develop addictions and undesirable side effects are the main causes reducing opioid efficiency in chronic pain treatment. Among many mechanisms connected to emerging of opioid resistance the ATP-binding cassette (ABC transporters present at the blood-brain barrier may play an important role. These transporter proteins, especially P-glycoprotein (ABCB1, MDR1, affect pharmacokinetics of many drugs and xenobiotics that are their substrates. ABC transporters reduce cellular uptake of drugs and/or increase their export from brain tissue to blood. Substrate specificity of P-glycoprotein is extremely wide and comprises many structurally and functionally unrelated compounds. What is interesting, substrate specificity of P-glycoprotein overlaps to a great extent the specificity of the isoforms of cytochrome P450 involved in drug metabolism. In the present review, the ABC proteins-mediated transport of opioids was discussed as well as the mechanisms of transport regulation. Cellular metabolism of various opioid drugs and the role of ABC transporters in their absorption, distribution and elimination were also described.

  4. ATP binding and hydrolysis disrupt the high-affinity interaction between the heme ABC transporter HmuUV and its cognate substrate-binding protein.

    Science.gov (United States)

    Qasem-Abdullah, Hiba; Perach, Michal; Livnat-Levanon, Nurit; Lewinson, Oded

    2017-09-01

    Using the energy of ATP hydrolysis, ABC transporters catalyze the trans-membrane transport of molecules. In bacteria, these transporters partner with a high-affinity substrate-binding protein (SBP) to import essential micronutrients. ATP binding by Type I ABC transporters (importers of amino acids, sugars, peptides, and small ions) stabilizes the interaction between the transporter and the SBP, thus allowing transfer of the substrate from the latter to the former. In Type II ABC transporters (importers of trace elements, e.g. vitamin B 12 , heme, and iron-siderophores) the role of ATP remains debatable. Here we studied the interaction between the Yersinia pestis ABC heme importer (HmuUV) and its partner substrate-binding protein (HmuT). Using real-time surface plasmon resonance experiments and interaction studies in membrane vesicles, we find that in the absence of ATP the transporter and the SBP tightly bind. Substrate in excess inhibits this interaction, and ATP binding by the transporter completely abolishes it. To release the stable docked SBP from the transporter hydrolysis of ATP is required. Based on these results we propose a mechanism for heme acquisition by HmuUV-T where the substrate-loaded SBP docks to the nucleotide-free outward-facing conformation of the transporter. ATP binding leads to formation of an occluded state with the substrate trapped in the trans-membrane translocation cavity. Subsequent ATP hydrolysis leads to substrate delivery to the cytoplasm, release of the SBP, and resetting of the system. We propose that other Type II ABC transporters likely share the fundamentals of this mechanism. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Regulation of ABC transporters blood-brain barrier: the good, the bad, and the ugly.

    Science.gov (United States)

    Miller, David S

    2015-01-01

    The brain capillary endothelial cells that constitute the blood-brain barrier express multiple ABC transport proteins on the luminal, blood-facing, plasma membrane. These transporters function as ATP-driven efflux pumps for xenobiotics and endogenous metabolites. High expression of these ABC transporters at the barrier is a major obstacle to the delivery of therapeutics, including chemotherapeutics, to the CNS. Here, I review the signals that alter ABC transporter expression and transport function with an emphasis on P-glycoprotein, Mrp2, and breast cancer resistance protein (BCRP), the efflux transporters for which we have the most detailed picture of regulation. Recent work shows that transporter protein expression can be upregulated in response to inflammatory and oxidative stress, therapeutic drugs, diet, and persistent environmental pollutants; as a consequence, drug delivery to the brain is reduced (potentially bad and ugly). In contrast, basal transport activity of P-glycoprotein and BCRP can be reduced through complex signaling pathways that involve events in and on the brain capillary endothelial cells. Targeting these signaling events provides opportunities to rapidly and reversibly increase brain accumulation of drugs that are substrates for the transporters (potentially good). The clinical usefulness of targeting signaling to reduce efflux transporter activity and improve drug delivery to the CNS remains to be established. © 2015 Elsevier Inc. All rights reserved.

  6. Structural basis for antibacterial peptide self-immunity by the bacterial ABC transporter McjD.

    Science.gov (United States)

    Bountra, Kiran; Hagelueken, Gregor; Choudhury, Hassanul G; Corradi, Valentina; El Omari, Kamel; Wagner, Armin; Mathavan, Indran; Zirah, Séverine; Yuan Wahlgren, Weixiao; Tieleman, D Peter; Schiemann, Olav; Rebuffat, Sylvie; Beis, Konstantinos

    2017-10-16

    Certain pathogenic bacteria produce and release toxic peptides to ensure either nutrient availability or evasion from the immune system. These peptides are also toxic to the producing bacteria that utilize dedicated ABC transporters to provide self-immunity. The ABC transporter McjD exports the antibacterial peptide MccJ25 in Escherichia coli Our previously determined McjD structure provided some mechanistic insights into antibacterial peptide efflux. In this study, we have determined its structure in a novel conformation, apo inward-occluded and a new nucleotide-bound state, high-energy outward-occluded intermediate state, with a defined ligand binding cavity. Predictive cysteine cross-linking in E. coli membranes and PELDOR measurements along the transport cycle indicate that McjD does not undergo major conformational changes as previously proposed for multi-drug ABC exporters. Combined with transport assays and molecular dynamics simulations, we propose a novel mechanism for toxic peptide ABC exporters that only requires the transient opening of the cavity for release of the peptide. We propose that shielding of the cavity ensures that the transporter is available to export the newly synthesized peptides, preventing toxic-level build-up. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  7. A wheat ABC transporter contributes to both grain formation and mycotoxin tolerance

    Science.gov (United States)

    Deoxynivalenol (DON) is a mycotoxin produced by Fusarium fungi which acts as a disease virulence factor, aiding fungal pathogenesis of cereals spikelets and spread of the economically important Fusarium head blight (FHB) disease. Previously, a fragment of a wheat ABC transporter gene was shown to be...

  8. Genetic variation in ABC transporter A1 contributes to HDL cholesterol in the general population

    DEFF Research Database (Denmark)

    Frikke-Schmidt, Ruth; Nordestgaard, Børge G; Jensen, Gorm B

    2004-01-01

    Homozygosity for mutations in ABC transporter A1 (ABCA1) causes Tangier disease, a rare HDL-deficiency syndrome. Whether heterozygosity for genetic variation in ABCA1 also contributes to HDL cholesterol (HDL-C) levels in the general population is presently unclear. We determined whether mutations...

  9. Gangliosides do not affect ABC transporter function in human neuroblastoma cells

    NARCIS (Netherlands)

    Dijkhuis, Anne-Jan; Klappe, Karin; Kamps, Willem; Sietsma, Hannie; Kok, Jan Willem

    Previous studies have indicated a role for glucosylceramide synthase (GCS) in multidrug resistance (MDR), either related to turnover of ceramide (Cer) or generation of gangliosides, which modulate apoptosis and/or the activity of ABC transporters. This study challenges the hypothesis that

  10. Influence of detergents on the activity of the ABC transporter LmrA

    NARCIS (Netherlands)

    Infed, Nacera; Hanekop, Nils; Driessen, Arnold J. M.; Smits, Sander H. J.; Schmitt, Lutz

    The ABC transporter LmrA from Lactococcus lactis has been intensively studied and a role in multidrug resistance was proposed. Here, we performed a comprehensive detergent screen to analyze the impact of detergents for a successful solubilization, purification and retention of functional properties

  11. Phosphorylation is required for the pathogen defense function of the Arabidopsis PEN3 ABC transporter

    Science.gov (United States)

    The Arabidopsis PEN3 ABC transporter accumulates at sites of pathogen detection, where it is involved in defense against multiple pathogens. Perception of PAMPs by pattern recognition receptors initiates recruitment of PEN3 and also leads to PEN3 phosphorylation at multiple amino acid residues. Whet...

  12. Tissue-Specific Transcript Profiling for ABC Transporters in the Sequestering Larvae of the Phytophagous Leaf Beetle Chrysomela populi

    Science.gov (United States)

    Gretscher, René R.; Groth, Marco; Boland, Wilhelm; Burse, Antje

    2014-01-01

    Background Insects evolved ingenious adaptations to use extraordinary food sources. Particularly, the diet of herbivores enriched with noxious plant secondary metabolites requires detoxification mechanisms. Sequestration, which involves the uptake, transfer, and concentration of occasionally modified phytochemicals into specialized tissues or hemolymph, is one of the most successful detoxification strategies found in most insect orders. Due to the ability of ATP-binding cassette (ABC) carriers to transport a wide range of molecules including phytochemicals and xenobiotics, it is highly likely that they play a role in this sequestration process. To shed light on the role of ABC proteins in sequestration, we describe an inventory of putative ABC transporters in various tissues in the sequestering juvenile poplar leaf beetle, Chrysomela populi. Results In the transcriptome of C. populi, we predicted 65 ABC transporters. To link the proteins with a possible function, we performed comparative phylogenetic analyses with ABC transporters of other insects and of humans. While tissue-specific profiling of each ABC transporter subfamily suggests that ABCB, C and G influence the plant metabolite absorption in the gut, ABCC with 14 members is the preferred subfamily responsible for the excretion of these metabolites via Malpighian tubules. Moreover, salicin, which is sequestered from poplar plants, is translocated into the defensive glands for further deterrent production. In these glands and among all identified ABC transporters, an exceptionally high transcript level was observed only for Cpabc35 (Cpmrp). RNAi revealed the deficiency of other ABC pumps to compensate the function of CpABC35, demonstrating its key role during sequestration. Conclusion We provide the first comprehensive phylogenetic study of the ABC family in a phytophagous beetle species. RNA-seq data from different larval tissues propose the importance of ABC pumps to achieve a homeostasis of plant

  13. Tissue-specific transcript profiling for ABC transporters in the sequestering larvae of the phytophagous leaf beetle Chrysomela populi.

    Directory of Open Access Journals (Sweden)

    Anja S Strauss

    Full Text Available Insects evolved ingenious adaptations to use extraordinary food sources. Particularly, the diet of herbivores enriched with noxious plant secondary metabolites requires detoxification mechanisms. Sequestration, which involves the uptake, transfer, and concentration of occasionally modified phytochemicals into specialized tissues or hemolymph, is one of the most successful detoxification strategies found in most insect orders. Due to the ability of ATP-binding cassette (ABC carriers to transport a wide range of molecules including phytochemicals and xenobiotics, it is highly likely that they play a role in this sequestration process. To shed light on the role of ABC proteins in sequestration, we describe an inventory of putative ABC transporters in various tissues in the sequestering juvenile poplar leaf beetle, Chrysomela populi.In the transcriptome of C. populi, we predicted 65 ABC transporters. To link the proteins with a possible function, we performed comparative phylogenetic analyses with ABC transporters of other insects and of humans. While tissue-specific profiling of each ABC transporter subfamily suggests that ABCB, C and G influence the plant metabolite absorption in the gut, ABCC with 14 members is the preferred subfamily responsible for the excretion of these metabolites via Malpighian tubules. Moreover, salicin, which is sequestered from poplar plants, is translocated into the defensive glands for further deterrent production. In these glands and among all identified ABC transporters, an exceptionally high transcript level was observed only for Cpabc35 (Cpmrp. RNAi revealed the deficiency of other ABC pumps to compensate the function of CpABC35, demonstrating its key role during sequestration.We provide the first comprehensive phylogenetic study of the ABC family in a phytophagous beetle species. RNA-seq data from different larval tissues propose the importance of ABC pumps to achieve a homeostasis of plant-derived compounds and

  14. Tissue-specific transcript profiling for ABC transporters in the sequestering larvae of the phytophagous leaf beetle Chrysomela populi.

    Science.gov (United States)

    Strauss, Anja S; Wang, Ding; Stock, Magdalena; Gretscher, René R; Groth, Marco; Boland, Wilhelm; Burse, Antje

    2014-01-01

    Insects evolved ingenious adaptations to use extraordinary food sources. Particularly, the diet of herbivores enriched with noxious plant secondary metabolites requires detoxification mechanisms. Sequestration, which involves the uptake, transfer, and concentration of occasionally modified phytochemicals into specialized tissues or hemolymph, is one of the most successful detoxification strategies found in most insect orders. Due to the ability of ATP-binding cassette (ABC) carriers to transport a wide range of molecules including phytochemicals and xenobiotics, it is highly likely that they play a role in this sequestration process. To shed light on the role of ABC proteins in sequestration, we describe an inventory of putative ABC transporters in various tissues in the sequestering juvenile poplar leaf beetle, Chrysomela populi. In the transcriptome of C. populi, we predicted 65 ABC transporters. To link the proteins with a possible function, we performed comparative phylogenetic analyses with ABC transporters of other insects and of humans. While tissue-specific profiling of each ABC transporter subfamily suggests that ABCB, C and G influence the plant metabolite absorption in the gut, ABCC with 14 members is the preferred subfamily responsible for the excretion of these metabolites via Malpighian tubules. Moreover, salicin, which is sequestered from poplar plants, is translocated into the defensive glands for further deterrent production. In these glands and among all identified ABC transporters, an exceptionally high transcript level was observed only for Cpabc35 (Cpmrp). RNAi revealed the deficiency of other ABC pumps to compensate the function of CpABC35, demonstrating its key role during sequestration. We provide the first comprehensive phylogenetic study of the ABC family in a phytophagous beetle species. RNA-seq data from different larval tissues propose the importance of ABC pumps to achieve a homeostasis of plant-derived compounds and offer a basis for

  15. Congruence ABC implies ABC

    OpenAIRE

    Ellenberg, Jordan S.

    2000-01-01

    The ABC conjecture of Masser and Oesterle' states that if (a,b,c) are coprime integers with a + b + c = 0, then sup(|a|,|b|,|c|) 0. Oesterle' has observed that if the ABC conjecture holds for all (a,b,c) with 16 | abc, then the full ABC conjecture holds. We extend that result to show that, for every integer N, the "congruence ABC conjecture" that ABC holds for all (a,b,c) with N|abc implies the full ABC conjecture.

  16. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    Science.gov (United States)

    Bhattacharjee, Sourav; van Opstal, Edward J.; Alink, Gerrit M.; Marcelis, Antonius T. M.; Zuilhof, Han; Rietjens, Ivonne M. C. M.

    2013-06-01

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/size 45 nm) and polystyrene nanoparticles (PSNPs/size 50 nm), with different surface charges (positive and negative), was quantified. The positive PNPs showed a higher intracellular uptake and flux across the Caco-2 monolayers than the negative PNPs. Multidrug resistance/P-glycoprotein (MDR1/P-gp), a specific ATP-binding cassette (ABC) transporter, was found to play a major role in the cellular efflux of positive PNPs, whereas the multidrug resistance protein 1 took part in the efflux of negative PNPs from Caco-2 cells. The positive PNPs also caused an increased cellular uptake and apical to basolateral transport of the carcinogen PhIP across the Caco-2 monolayer. The flavonoid quercetin, which is known to interact with ABC transporters, promoted the intracellular uptake of different PNPs and interfered with the normal distribution patterns of PNPs in the transwell system. These results indicate that PNPs display surface charge-specific interactions with ABC transporters and can even affect the bioavailability of toxic food-borne compounds (like pro-carcinogens).

  17. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Sourav, E-mail: sourav.bhattacharjee@wur.nl [Wageningen University, Laboratory of Organic Chemistry (Netherlands); Opstal, Edward J. van; Alink, Gerrit M. [Wageningen University, Division of Toxicology (Netherlands); Marcelis, Antonius T. M.; Zuilhof, Han [Wageningen University, Laboratory of Organic Chemistry (Netherlands); Rietjens, Ivonne M. C. M. [Wageningen University, Division of Toxicology (Netherlands)

    2013-06-15

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/size {approx}45 nm) and polystyrene nanoparticles (PSNPs/size {approx}50 nm), with different surface charges (positive and negative), was quantified. The positive PNPs showed a higher intracellular uptake and flux across the Caco-2 monolayers than the negative PNPs. Multidrug resistance/P-glycoprotein (MDR1/P-gp), a specific ATP-binding cassette (ABC) transporter, was found to play a major role in the cellular efflux of positive PNPs, whereas the multidrug resistance protein 1 took part in the efflux of negative PNPs from Caco-2 cells. The positive PNPs also caused an increased cellular uptake and apical to basolateral transport of the carcinogen PhIP across the Caco-2 monolayer. The flavonoid quercetin, which is known to interact with ABC transporters, promoted the intracellular uptake of different PNPs and interfered with the normal distribution patterns of PNPs in the transwell system. These results indicate that PNPs display surface charge-specific interactions with ABC transporters and can even affect the bioavailability of toxic food-borne compounds (like pro-carcinogens).

  18. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    International Nuclear Information System (INIS)

    Bhattacharjee, Sourav; Opstal, Edward J. van; Alink, Gerrit M.; Marcelis, Antonius T. M.; Zuilhof, Han; Rietjens, Ivonne M. C. M.

    2013-01-01

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/size ∼45 nm) and polystyrene nanoparticles (PSNPs/size ∼50 nm), with different surface charges (positive and negative), was quantified. The positive PNPs showed a higher intracellular uptake and flux across the Caco-2 monolayers than the negative PNPs. Multidrug resistance/P-glycoprotein (MDR1/P-gp), a specific ATP-binding cassette (ABC) transporter, was found to play a major role in the cellular efflux of positive PNPs, whereas the multidrug resistance protein 1 took part in the efflux of negative PNPs from Caco-2 cells. The positive PNPs also caused an increased cellular uptake and apical to basolateral transport of the carcinogen PhIP across the Caco-2 monolayer. The flavonoid quercetin, which is known to interact with ABC transporters, promoted the intracellular uptake of different PNPs and interfered with the normal distribution patterns of PNPs in the transwell system. These results indicate that PNPs display surface charge-specific interactions with ABC transporters and can even affect the bioavailability of toxic food-borne compounds (like pro-carcinogens).

  19. ATP-binding cassette (ABC) transporter expression and localization in sea urchin development.

    Science.gov (United States)

    Shipp, Lauren E; Hamdoun, Amro

    2012-06-01

    ATP-binding cassette (ABC) transporters are membrane proteins that regulate intracellular concentrations of myriad compounds and ions. There are >100 ABC transporter predictions in the Strongylocentrotus purpuratus genome, including 40 annotated ABCB, ABCC, and ABCG "multidrug efflux" transporters. Despite the importance of multidrug transporters for protection and signaling, their expression patterns have not been characterized in deuterostome embryos. Sea urchin embryos expressed 20 ABCB, ABCC, and ABCG transporter genes in the first 58 hr of development, from unfertilized egg to early prism. We quantified transcripts of ABCB1a, ABCB4a, ABCC1, ABCC5a, ABCC9a, and ABCG2b, and found that ABCB1a mRNA was 10-100 times more abundant than other transporter mRNAs. In situ hybridization showed ABCB1a was expressed ubiquitously in embryos, while ABCC5a was restricted to secondary mesenchyme cells and their precursors. Fluorescent protein fusions showed localization of ABCB1a on apical cell surfaces, and ABCC5a on basolateral surfaces. Embryos use many ABC transporters with predicted functions in cell signaling, lysosomal and mitochondrial homeostasis, potassium channel regulation, pigmentation, and xenobiotic efflux. Detailed characterization of ABCB1a and ABCC5a revealed that they have different temporal and spatial gene expression profiles and protein localization patterns that correlate to their predicted functions in protection and development, respectively. Copyright © 2012 Wiley Periodicals, Inc.

  20. Putative ABC transporter responsible for acetic acid resistance in Acetobacter aceti.

    Science.gov (United States)

    Nakano, Shigeru; Fukaya, Masahiro; Horinouchi, Sueharu

    2006-01-01

    Two-dimensional gel electrophoretic analysis of the membrane fraction of Acetobacter aceti revealed the presence of several proteins that were produced in response to acetic acid. A 60-kDa protein, named AatA, which was mostly induced by acetic acid, was prepared; aatA was cloned on the basis of its NH2-terminal amino acid sequence. AatA, consisting of 591 amino acids and containing ATP-binding cassette (ABC) sequences and ABC signature sequences, belonged to the ABC transporter superfamily. The aatA mutation with an insertion of the neomycin resistance gene within the aatA coding region showed reduced resistance to acetic acid, formic acid, propionic acid, and lactic acid, whereas the aatA mutation exerted no effects on resistance to various drugs, growth at low pH (adjusted with HCl), assimilation of acetic acid, or resistance to citric acid. Introduction of plasmid pABC101 containing aatA under the control of the Escherichia coli lac promoter into the aatA mutant restored the defect in acetic acid resistance. In addition, pABC101 conferred acetic acid resistance on E. coli. These findings showed that AatA was a putative ABC transporter conferring acetic acid resistance on the host cell. Southern blot analysis and subsequent nucleotide sequencing predicted the presence of aatA orthologues in a variety of acetic acid bacteria belonging to the genera Acetobacter and Gluconacetobacter. The fermentation with A. aceti containing aatA on a multicopy plasmid resulted in an increase in the final yield of acetic acid.

  1. The mitochondrial transporter ABC-me (ABCB10), a downstream target of GATA-1, is essential for erythropoiesis in vivo

    Science.gov (United States)

    Hyde, B B; Liesa, M; Elorza, A A; Qiu, W; Haigh, S E; Richey, L; Mikkola, H K; Schlaeger, T M; Shirihai, O S

    2012-01-01

    The mitochondrial transporter ATP binding cassette mitochondrial erythroid (ABC-me/ABCB10) is highly induced during erythroid differentiation by GATA-1 and its overexpression increases hemoglobin production rates in vitro. However, the role of ABC-me in erythropoiesis in vivo is unknown. Here we report for the first time that erythrocyte development in mice requires ABC-me. ABC-me−/− mice die at day 12.5 of gestation, showing nearly complete eradication of primitive erythropoiesis and lack of hemoglobinized cells at day 10.5. ABC-me−/− erythroid cells fail to differentiate because they exhibit a marked increase in apoptosis, both in vivo and ex vivo. Erythroid precursors are particularly sensitive to oxidative stress and ABC-me in the heart and its yeast ortholog multidrug resistance-like 1 have been shown to protect against oxidative stress. Thus, we hypothesized that increased apoptosis in ABC-me−/− erythroid precursors was caused by oxidative stress. Within this context, ABC-me deletion causes an increase in mitochondrial superoxide production and protein carbonylation in erythroid precursors. Furthermore, treatment of ABC-me−/− erythroid progenitors with the mitochondrial antioxidant MnTBAP (superoxide dismutase 2 mimetic) supports survival, ex vivo differentiation and increased hemoglobin production. Altogether, our findings demonstrate that ABC-me is essential for erythropoiesis in vivo. PMID:22240895

  2. Functional analysis of ABC transporter genes from Botrytis cinerea identifies BcatrB as a transporter of eugenol

    NARCIS (Netherlands)

    Schoonbeek, H.; Nistelrooy, van J.G.M.; Waard, de M.A.

    2003-01-01

    The role of multiple ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporter genes from the plant pathogenic fungus Botrytis cinerea in protection against natural fungitoxic compounds was studied by expression analysis and phenotyping of gene-replacement mutants. The

  3. Genome-wide identification, characterization and phylogenetic analysis of 50 catfish ATP-binding cassette (ABC transporter genes.

    Directory of Open Access Journals (Sweden)

    Shikai Liu

    Full Text Available Although a large set of full-length transcripts was recently assembled in catfish, annotation of large gene families, especially those with duplications, is still a great challenge. Most often, complexities in annotation cause mis-identification and thereby much confusion in the scientific literature. As such, detailed phylogenetic analysis and/or orthology analysis are required for annotation of genes involved in gene families. The ATP-binding cassette (ABC transporter gene superfamily is a large gene family that encodes membrane proteins that transport a diverse set of substrates across membranes, playing important roles in protecting organisms from diverse environment.In this work, we identified a set of 50 ABC transporters in catfish genome. Phylogenetic analysis allowed their identification and annotation into seven subfamilies, including 9 ABCA genes, 12 ABCB genes, 12 ABCC genes, 5 ABCD genes, 2 ABCE genes, 4 ABCF genes and 6 ABCG genes. Most ABC transporters are conserved among vertebrates, though cases of recent gene duplications and gene losses do exist. Gene duplications in catfish were found for ABCA1, ABCB3, ABCB6, ABCC5, ABCD3, ABCE1, ABCF2 and ABCG2.The whole set of catfish ABC transporters provide the essential genomic resources for future biochemical, toxicological and physiological studies of ABC drug efflux transporters. The establishment of orthologies should allow functional inferences with the information from model species, though the function of lineage-specific genes can be distinct because of specific living environment with different selection pressure.

  4. Role of ABC transporters in veterinary medicine: pharmaco-toxicological implications.

    Science.gov (United States)

    Virkel, Guillermo; Ballent, Mariana; Lanusse, Carlos; Lifschitz, Adrian

    2018-01-31

    Unlike physicians, veterinary practitioners must deal with a number of animal species with crucial differences in anatomy, physiology and metabolism. Accordingly, the pharmacokinetic behaviour, the clinical efficacy and the adverse or toxic effects of drugs may differ across domestic animals. Moreover, the use of drugs in food-producing species may impose a risk for humans due to the generation of chemical residues in edible products, a major concern for public health and consumer's safety. As is clearly known in human beings, the ATP binding cassette (ABC) of transport proteins may influence the bioavailability and elimination of numerous drugs and other xenobiotics in domestic animals as well. A number of drugs, currently available in the veterinary market, are substrates of one or more transporters. Therefore, significant drug-drug interactions among ABC substrates may have unpredictable pharmaco-toxicological consequences in different species of veterinary interest. In this context, different investigations revealed the major relevance of P-gp and other transport proteins, like breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins (MRPs), in both companion and livestock animals. Undoubtedly, the discovery of the ABC transporters and the deep understanding of their physiological role in the different species introduced a new paradigm into the veterinary pharmacology. This review focus on the expression and function of the major transport proteins expressed in species of veterinary interest, and their impact in drug disposition, efficacy and toxicity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. ABC transporters and xenobiotic defense systems in early life stages of rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Kropf, Christian; Segner, Helmut; Fent, Karl

    2016-01-01

    Embryos of oviparous fish, in contrast to (ovo) viviparous species, develop in the aquatic environment, and therefore need solute transport systems at their body surfaces for maintaining internal homeostasis and defending against potentially harmful substances. We hypothesized that solute transporters undergo changes in tissue distribution from the embryo to the larval stage. We therefore studied the mRNA profiles of eight ABC transporters (abcb1a, abcb1b, abcc1, abcc2, abcc3, abcc4, abcc5, abcg2) and three solute carriers (oatp1d, putative oatp2 putative, mate1) in different body regions (head, yolk sac epithelium, abdominal viscera, skin/muscles) of developing rainbow trout. Additionally, we investigated mRNA levels of phase I (cyp1a, cyp3a) and phase II (gstp, putative ugt1, putative ugt2) biotransformation enzymes. The study covered the developmental period from the eleuthero-embryo stage to the first-feeding larval stage (1-20days post-hatch, dph). At 1dph, transcripts of abcc2, abcc4, abcg2, cyp3a, gstp, putative mate1, and putative oatp2 occurred primarily in the yolk sac epithelium, whereas at later stages expression of these genes was predominantly observed in the abdominal viscera. The functional activity of ABC transporters in fish early life stages was assessed by rhodamine B accumulation assays. Finally, we investigated the potential impact of xenobiotics (clotrimazole, clofibric acid) on the ABC and biotransformation systems of trout early life stages. While clofibric acid had no effect, clotrimazole lead to an increased rhodamine B accumulation. The results provide evidence that the transition from the eleuthero-embryo to the larval stage is accompanied by a major alteration in tissue expression of ABC transporters. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Predictive Structure and Topology of Peroxisomal ATP-Binding Cassette (ABC) Transporters

    Science.gov (United States)

    Andreoletti, Pierre; Raas, Quentin; Gondcaille, Catherine; Cherkaoui-Malki, Mustapha; Trompier, Doriane; Savary, Stéphane

    2017-01-01

    The peroxisomal ATP-binding Cassette (ABC) transporters, which are called ABCD1, ABCD2 and ABCD3, are transmembrane proteins involved in the transport of various lipids that allow their degradation inside the organelle. Defective ABCD1 leads to the accumulation of very long-chain fatty acids and is associated with a complex and severe neurodegenerative disorder called X-linked adrenoleukodystrophy (X-ALD). Although the nucleotide-binding domain is highly conserved and characterized within the ABC transporters family, solid data are missing for the transmembrane domain (TMD) of ABCD proteins. The lack of a clear consensus on the secondary and tertiary structure of the TMDs weakens any structure-function hypothesis based on the very diverse ABCD1 mutations found in X-ALD patients. Therefore, we first reinvestigated thoroughly the structure-function data available and performed refined alignments of ABCD protein sequences. Based on the 2.85  Å resolution crystal structure of the mitochondrial ABC transporter ABCB10, here we propose a structural model of peroxisomal ABCD proteins that specifies the position of the transmembrane and coupling helices, and highlight functional motifs and putative important amino acid residues. PMID:28737695

  7. Predictive Structure and Topology of Peroxisomal ATP-Binding Cassette (ABC Transporters

    Directory of Open Access Journals (Sweden)

    Pierre Andreoletti

    2017-07-01

    Full Text Available The peroxisomal ATP-binding Cassette (ABC transporters, which are called ABCD1, ABCD2 and ABCD3, are transmembrane proteins involved in the transport of various lipids that allow their degradation inside the organelle. Defective ABCD1 leads to the accumulation of very long-chain fatty acids and is associated with a complex and severe neurodegenerative disorder called X-linked adrenoleukodystrophy (X-ALD. Although the nucleotide-binding domain is highly conserved and characterized within the ABC transporters family, solid data are missing for the transmembrane domain (TMD of ABCD proteins. The lack of a clear consensus on the secondary and tertiary structure of the TMDs weakens any structure-function hypothesis based on the very diverse ABCD1 mutations found in X-ALD patients. Therefore, we first reinvestigated thoroughly the structure-function data available and performed refined alignments of ABCD protein sequences. Based on the 2.85  Å resolution crystal structure of the mitochondrial ABC transporter ABCB10, here we propose a structural model of peroxisomal ABCD proteins that specifies the position of the transmembrane and coupling helices, and highlight functional motifs and putative important amino acid residues.

  8. Discovery of an auto-regulation mechanism for the maltose ABC transporter MalFGK2.

    Directory of Open Access Journals (Sweden)

    Huan Bao

    Full Text Available The maltose transporter MalFGK(2, together with the substrate-binding protein MalE, is one of the best-characterized ABC transporters. In the conventional model, MalE captures maltose in the periplasm and delivers the sugar to the transporter. Here, using nanodiscs and proteoliposomes, we instead find that MalE is bound with high-affinity to MalFGK2 to facilitate the acquisition of the sugar. When the maltose concentration exceeds the transport capacity, MalE captures maltose and dissociates from the transporter. This mechanism explains why the transport rate is high when MalE has low affinity for maltose, and low when MalE has high affinity for maltose. Transporter-bound MalE facilitates the acquisition of the sugar at low concentrations, but also captures and dissociates from the transporter past a threshold maltose concentration. In vivo, this maltose-forced dissociation limits the rate of transport. Given the conservation of the substrate-binding proteins, this mode of allosteric regulation may be universal to ABC importers.

  9. Brain barriers and functional interfaces with sequential appearance of ABC efflux transporters during human development

    DEFF Research Database (Denmark)

    Møllgård, Kjeld; Dziegielewska, Katarzyna M.; Holst, Camilla B.

    2017-01-01

    Adult brain is protected from entry of drugs and toxins by specific mechanisms such as ABC (ATP-binding Cassette) efflux transporters. Little is known when these appear in human brain during development. Cellular distribution of three main ABC transporters (ABCC1, ABCG2, ABCB1) was determined...... at blood-brain barriers and interfaces in human embryos and fetuses in first half of gestation. Antibodies against claudin-5 and-11 and antibodies to α-fetoprotein were used to describe morphological and functional aspects of brain barriers. First exchange interfaces to be established, probably at 4......-5 weeks post conception, are between brain and embryonic cerebrospinal fluid (eCSF) and between outer surface of brain anlage and primary meninx. They already exclude α-fetoprotein and are immunopositive for both claudins, ABCC1 and ABCG2. ABCB1 is detectable within a week of blood vessels first...

  10. Multidrug ABC transporter Cdr1 of Candida albicans harbors specific and overlapping binding sites for human steroid hormones transport.

    Science.gov (United States)

    Baghel, Pratima; Rawal, Manpreet Kaur; Khan, Mohammad Firoz; Sen, Sobhan; Siddiqui, Mohammed Haris; Chaptal, Vincent; Falson, Pierre; Prasad, Rajendra

    2017-10-01

    The present study examines the kinetics of steroids efflux mediated by the Candida drug resistance protein 1 (Cdr1p) and evaluates their interaction with the protein. We exploited our in-house mutant library for targeting the 252 residues forming the twelve transmembrane helices (TMHs) of Cdr1p. The screening revealed 65 and 58 residues critical for β-estradiol and corticosterone transport, respectively. Notably, up to 83% critical residues for corticosterone face the lipid interface compared to 54% for β-estradiol. Molecular docking identified a possible peripheral corticosterone-binding site made of 8/14 critical/non-critical residues between TMHs 3, 4 and 6. β-estradiol transport was severely hampered by alanine replacements of Cdr1p core residues involving TMHs 2, 5 and 8, in a binding site made of 10/14 critical residues mainly shared with rhodamine 6G with which it competes. By contrast, TMH11 was poorly impacted, although being part of the core domain. Finally, we observed the presence of several contiguous stretches of 3-5 critical residues in TMHs 2, 5 and 10 that points to a rotation motion of these helices during the substrate transport cycle. The selective structural arrangement of the steroid-binding pockets in the core region and at the lipid-TMD interface, which was never reported before, together with the possible rotation of some TMHs may be the structural basis of the drug-transport mechanism achieved by these type II ABC transporters. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. How to move an amphipathic molecule across a lipid bilayer: different mechanisms for different ABC transporters?

    Science.gov (United States)

    Theodoulou, Frederica L; Carrier, David J; Schaedler, Theresia A; Baldwin, Stephen A; Baker, Alison

    2016-06-15

    Import of β-oxidation substrates into peroxisomes is mediated by ATP binding cassette (ABC) transporters belonging to subfamily D. In order to enter the β-oxidation pathway, fatty acids are activated by conversion to fatty acyl-CoA esters, a reaction which is catalysed by acyl-CoA synthetases (ACSs). Here, we present evidence for an unusual transport mechanism, in which fatty acyl-CoA substrates are accepted by ABC subclass D protein (ABCD) transporters, cleaved by the transporters during transit across the lipid bilayer to release CoA, and ultimately re-esterified in the peroxisome lumen by ACSs which interact with the transporter. We propose that this solves the biophysical problem of moving an amphipathic molecule across the peroxisomal membrane, since the intrinsic thioesterase activity of the transporter permits separate membrane translocation pathways for the hydrophobic fatty acid moiety and the polar CoA moiety. The cleavage/re-esterification mechanism also has the potential to control entry of disparate substrates into the β-oxidation pathway when coupled with distinct peroxisomal ACSs. A different solution to the movement of amphipathic molecules across a lipid bilayer is deployed by the bacterial lipid-linked oligosaccharide (LLO) flippase, PglK, in which the hydrophilic head group and the hydrophobic polyprenyl tail of the substrate are proposed to have distinct translocation pathways but are not chemically separated during transport. We discuss a speculative alternating access model for ABCD proteins based on the mammalian ABC transporter associated with antigen processing (TAP) and compare it to the novel mechanism suggested by the recent PglK crystal structures and biochemical data. © 2016 The Author(s).

  12. Alzheimer's and ABC transporters--new opportunities for diagnostics and treatment.

    Science.gov (United States)

    Pahnke, Jens; Langer, Oliver; Krohn, Markus

    2014-12-01

    Much has been said about the increasing number of demented patients and the main risk factor 'age'. Frustratingly, we do not know the precise pattern and all modulating factors that provoke the pathologic changes in the brains of affected elderly. We have to diagnose early to be able to stop the progression of diseases that irreversibly destroy brain substance. Familiar AD cases have mislead some researchers for almost 20 years, which has unfortunately narrowed the scientific understanding and has, thus, lead to insufficient funding of independent approaches. Therefore, basic researchers hardly have been able to develop causative treatments and clinicians still do not have access to prognostic and early diagnostic tools. During the recent years it became clear that insufficient Aβ export, physiologically facilitated by the ABC transporter superfamily at the brain's barriers, plays a fundamental role in disease initiation and progression. Furthermore, export mechanisms that are deficient in affected elderly are new targets for activation and, thus, treatment, but ideally also for prevention. In sporadic AD disturbed clearance of β-amyloid from the brain is so far the most important factor for its accumulation in the parenchyma and vessel walls. Here, we review findings about the contribution of ABC transporters and of the perivascular drainage/glymphatic system on β-amyloid clearance. We highlight their potential value for innovative early diagnostics using PET and describe recently described, effective ABC transporter-targeting agents as potential causative treatment for neurodegenerative proteopathies/dementias. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. The ABC family of multidrug transporters in microorganisms

    NARCIS (Netherlands)

    van Veen, H.W; Konings, W.N

    1998-01-01

    Multidrug transporters are membrane proteins that are able to expel a broad range of toxic molecules from the cell. In humans, the overexpression of the multidrug resistance P-glycoprotein (Pgp) and the multidrug resistance-associated protein MRP1 (MRP) is a principal cause of resistance of cancers

  14. Maltose and maltodextrin utilization by Listeria monocytogenes depend on an inducible ABC transporter which is repressed by glucose.

    Directory of Open Access Journals (Sweden)

    Shubha Gopal

    2010-04-01

    Full Text Available In the environment as well as in the vertebrate intestine, Listeriae have access to complex carbohydrates like maltodextrins. Bacterial exploitation of such compounds requires specific uptake and utilization systems.We could show that Listeria monocytogenes and other Listeria species contain genes/gene products with high homology to the maltodextrin ABC transporter and utilization system of B. subtilis. Mutant construction and growth tests revealed that the L. monocytogenes gene cluster was required for the efficient utilization of maltodextrins as well as maltose. The gene for the ATP binding protein of the transporter was located distant from the cluster. Transcription analyses demonstrated that the system was induced by maltose/maltodextrins and repressed by glucose. Its induction was dependent on a LacI type transcriptional regulator. Repression by glucose was independent of the catabolite control protein CcpA, but was relieved in a mutant defective for Hpr kinase/phosphorylase.The data obtained show that in L. monocytogenes the uptake of maltodextrin and, in contrast to B. subtilis, also maltose is exclusively mediated by an ABC transporter. Furthermore, the results suggest that glucose repression of the uptake system possibly is by inducer exclusion, a mechanism not described so far in this organism.

  15. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana.

    Science.gov (United States)

    Stefanato, Francesca L; Abou-Mansour, Eliane; Buchala, Antony; Kretschmer, Matthias; Mosbach, Andreas; Hahn, Matthias; Bochet, Christian G; Métraux, Jean-Pierre; Schoonbeek, Henk-jan

    2009-05-01

    Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mutants. A B. cinerea strain lacking functional BcatrB is more sensitive to camalexin in vitro and less virulent on wild-type plants, but is still fully virulent on camalexin-deficient mutants. Pre-treatment of A. thaliana with UV-C leads to increased camalexin accumulation and substantial resistance to B. cinerea. UV-C-induced resistance was not seen in the camalexin-deficient mutants cyp79B2/B3, cyp71A13, pad3 or pad2, and was strongly reduced in ups1. Here we demonstrate that an ABC transporter is a virulence factor that increases tolerance of the pathogen towards a phytoalexin, and the complete restoration of virulence on host plants lacking this phytoalexin.

  16. Effect of Oxidative Stress on ABC Transporters: Contribution to Epilepsy Pharmacoresistance

    Directory of Open Access Journals (Sweden)

    Gurpreet Kaur Grewal

    2017-02-01

    Full Text Available Epilepsy is a neurological disorder affecting around 1%–2% of population worldwide and its treatment includes use of antiepileptic drugs to control seizures. Failure to respond to antiepileptic drug therapy is a major clinical problem and over expression of ATP-binding cassette transporters is considered one of the major reasons for pharmacoresistance. In this review, we have summarized the regulation of ABC transporters in response to oxidative stress due to disease and antiepileptic drugs. Further, ketogenic diet and antioxidants were examined for their role in pharmacoresistance. The understanding of signalling pathways and mechanism involved may help in identifying potential therapeutic targets and improving drug response.

  17. Computer-Aided Recognition of ABC Transporters Substrates and Its Application to the Development of New Drugs for Refractory Epilepsy.

    Science.gov (United States)

    Couyoupetrou, Manuel; Gantner, Melisa E; Di Ianni, Mauricio E; Palestro, Pablo H; Enrique, Andrea V; Gavernet, Luciana; Ruiz, Maria E; Pesce, Guido; Bruno-Blanch, Luis E; Talevi, Alan

    2017-01-01

    Despite the introduction of more than 15 third generation antiepileptic drugs to the market from 1990 to the moment, about one third of the epileptic patients still suffer from refractory to intractable epilepsy. Several hypotheses seek to explain the failure of drug treatments to control epilepsy symptoms in such patients. The most studied one proposes that drug resistance might be related with regional overactivity of efflux transporters from the ATP-Binding Cassette (ABC) superfamily at the blood-brain barrier and/or the epileptic foci in the brain. Different strategies have been conceived to address the transporter hypothesis, among them inhibiting or down-regulating the efflux transporters or bypassing them through a diversity of artifices. Here, we review scientific evidence supporting the transporter hypothesis along with its limitations, as well as computer-assisted early recognition of ABC transporter substrates as an interesting strategy to develop novel antiepileptic drugs capable of treating refractory epilepsy linked to ABC transporters overactivity.

  18. Early Observations of the Type Ia Supernova iPTF 16abc

    Science.gov (United States)

    Miller, Adam; iPTF Collaboration

    2018-01-01

    Early observations of Type Ia supernovae (SNe) provide a unique probe of their progenitor systems and explosion physics. Here, we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN only occurred 0.15 +0.15-0.07 d before our first detection. In the ~24 hr after discovery, iPTF 16abc rose by ~2 mag, following a near-linear rise in flux for ~3 d. Strong C II absorption is detected in the early spectra of iPTF 16abc, before disappearing after ~7 d. Unlike the extensively-observed Type Ia SN 2011fe, the (B-V)_0 colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling, or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including: (i) the rapid, near-linear rise, (ii) the non-evolving blue colors, and (iii) the strong absorption from ionized carbon, are the result of either vigorous mixing of radioactive-Ni in the SN ejecta, or ejecta interaction with diffuse material, or a combination of the two. In the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.

  19. Simulation of the coupling between nucleotide binding and transmembrane domains in the ABC transporter BtuCD

    DEFF Research Database (Denmark)

    Sonne, Jacob; Kandt, C.; Peters, Günther H.j.

    2007-01-01

    binding domains and the shared role of ATP in ABC transporters. The rearrangements in the cytoplasmic gate region do not provide enough space for B12 to diffuse from the transporter pore into the cytoplasm, which could suggest that peristaltic forces are needed to exclude B12 from the transporter pore....

  20. TetAB46, a predicted heterodimeric ABC transporter conferring tetracycline resistance in Streptococcus australis isolated from the oral cavity.

    Science.gov (United States)

    Warburton, Philip J; Ciric, Lena; Lerner, Avigdor; Seville, Lorna A; Roberts, Adam P; Mullany, Peter; Allan, Elaine

    2013-01-01

    To identify the genes responsible for tetracycline resistance in a strain of Streptococcus australis isolated from pooled saliva from healthy volunteers in France. S. australis is a viridans Streptococcus, originally isolated from the oral cavity of children in Australia, and subsequently reported in the lungs of cystic fibrosis patients and as a cause of invasive disease in an elderly patient. Agar containing 2 mg/L tetracycline was used for the isolation of tetracycline-resistant organisms. A genomic library in Escherichia coli was used to isolate the tetracycline resistance determinant. In-frame deletions and chromosomal repair were used to confirm function. Antibiotic susceptibility was determined by agar dilution and disc diffusion assay. The tetracycline resistance determinant from S. australis FRStet12 was isolated from a genomic library in E. coli and DNA sequencing showed two open reading frames predicted to encode proteins with similarity to multidrug resistance-type ABC transporters. Both genes were required for tetracycline resistance (to both the naturally occurring and semi-synthetic tetracyclines) and they were designated tetAB(46). This is the first report of a predicted ABC transporter conferring tetracycline resistance in a member of the oral microbiota.

  1. ATP-Binding Cassette (ABC) Transporters of the Human Respiratory Tract Pathogen, Moraxella catarrhalis: Role in Virulence.

    Science.gov (United States)

    Murphy, Timothy F; Brauer, Aimee L; Johnson, Antoinette; Kirkham, Charmaine

    2016-01-01

    Moraxella catarrhalis is a human respiratory tract pathogen that causes otitis media (middle ear infections) in children and respiratory tract infections in adults with chronic obstructive pulmonary disease. In view of the huge global burden of disease caused by M. catarrhalis, the development of vaccines to prevent these infections and better approaches to treatment have become priorities. In previous work, we used a genome mining approach that identified three substrate binding proteins (SBPs) of ATP-binding cassette (ABC) transporters as promising candidate vaccine antigens. In the present study, we performed a comprehensive assessment of 19 SBPs of 15 ABC transporter systems in the M. catarrhalis genome by engineering knockout mutants and studying their role in assays that assess mechanisms of infection. The capacity of M. catarrhalis to survive and grow in the nutrient-limited and hostile environment of the human respiratory tract, including intracellular growth, account in part for its virulence. The results show that ABC transporters that mediate uptake of peptides, amino acids, cations and anions play important roles in pathogenesis by enabling M. catarrhalis to 1) grow in nutrient-limited conditions, 2) invade and survive in human respiratory epithelial cells and 3) persist in the lungs in a murine pulmonary clearance model. The knockout mutants of SBPs and ABC transporters showed different patterns of activity in the assay systems, supporting the conclusion that different SBPs and ABC transporters function at different stages in the pathogenesis of infection. These results indicate that ABC transporters are nutritional virulence factors, functioning to enable the survival of M catarrhalis in the diverse microenvironments of the respiratory tract. Based on the role of ABC transporters as virulence factors of M. catarrhalis, these molecules represent potential drug targets to eradicate the organism from the human respiratory tract.

  2. An ABC transporter mutation is correlated with insect resistance to Bacillus thuringiensis Cry1Ac toxin.

    Directory of Open Access Journals (Sweden)

    Linda J Gahan

    2010-12-01

    Full Text Available Transgenic crops producing insecticidal toxins from Bacillus thuringiensis (Bt are commercially successful in reducing pest damage, yet knowledge of resistance mechanisms that threaten their sustainability is incomplete. Insect resistance to the pore-forming Cry1Ac toxin is correlated with the loss of high-affinity, irreversible binding to the mid-gut membrane, but the genetic factors responsible for this change have been elusive. Mutations in a 12-cadherin-domain protein confer some Cry1Ac resistance but do not block this toxin binding in in vitro assays. We sought to identify mutations in other genes that might be responsible for the loss of binding. We employed a map-based cloning approach using a series of backcrosses with 1,060 progeny to identify a resistance gene in the cotton pest Heliothis virescens that segregated independently from the cadherin mutation. We found an inactivating mutation of the ABC transporter ABCC2 that is genetically linked to Cry1Ac resistance and is correlated with loss of Cry1Ac binding to membrane vesicles. ABC proteins are integral membrane proteins with many functions, including export of toxic molecules from the cell, but have not been implicated in the mode of action of Bt toxins before. The reduction in toxin binding due to the inactivating mutation suggests that ABCC2 is involved in membrane integration of the toxin pore. Our findings suggest that ABC proteins may play a key role in the mode of action of Bt toxins and that ABC protein mutations can confer high levels of resistance that could threaten the continued utilization of Bt-expressing crops. However, such mutations may impose a physiological cost on resistant insects, by reducing export of other toxins such as plant secondary compounds from the cell. This weakness could be exploited to manage this mechanism of Bt resistance in the field.

  3. An ABC transporter mutation is correlated with insect resistance to Bacillus thuringiensis Cry1Ac toxin.

    Science.gov (United States)

    Gahan, Linda J; Pauchet, Yannick; Vogel, Heiko; Heckel, David G

    2010-12-16

    Transgenic crops producing insecticidal toxins from Bacillus thuringiensis (Bt) are commercially successful in reducing pest damage, yet knowledge of resistance mechanisms that threaten their sustainability is incomplete. Insect resistance to the pore-forming Cry1Ac toxin is correlated with the loss of high-affinity, irreversible binding to the mid-gut membrane, but the genetic factors responsible for this change have been elusive. Mutations in a 12-cadherin-domain protein confer some Cry1Ac resistance but do not block this toxin binding in in vitro assays. We sought to identify mutations in other genes that might be responsible for the loss of binding. We employed a map-based cloning approach using a series of backcrosses with 1,060 progeny to identify a resistance gene in the cotton pest Heliothis virescens that segregated independently from the cadherin mutation. We found an inactivating mutation of the ABC transporter ABCC2 that is genetically linked to Cry1Ac resistance and is correlated with loss of Cry1Ac binding to membrane vesicles. ABC proteins are integral membrane proteins with many functions, including export of toxic molecules from the cell, but have not been implicated in the mode of action of Bt toxins before. The reduction in toxin binding due to the inactivating mutation suggests that ABCC2 is involved in membrane integration of the toxin pore. Our findings suggest that ABC proteins may play a key role in the mode of action of Bt toxins and that ABC protein mutations can confer high levels of resistance that could threaten the continued utilization of Bt-expressing crops. However, such mutations may impose a physiological cost on resistant insects, by reducing export of other toxins such as plant secondary compounds from the cell. This weakness could be exploited to manage this mechanism of Bt resistance in the field.

  4. Reversal of resistance by GF120918 in cell lines expressing the ABC half-transporter, MXR

    DEFF Research Database (Denmark)

    de Bruin, M; Miyake, K; Litman, Thomas

    1999-01-01

    The emergence of several newly identified members of the ABC transporter family has necessitated the development of antagonists that are able to inhibit more than one transporter. We assessed the ability of the chemosensitizer GF120918 to function as a multispecific antagonist using cytotoxicity...... assays, rhodamine and calcein efflux assays, and confocal microscopy in cell lines expressing different multidrug resistance transporters. At a concentration of 1 microM in cytotoxicity assays, GF120918 was able to sensitize both S1-B1-20, a subline expressing P-glycoprotein (Pgp), and S1-M1......-80, a subline expressing a newly identified mitoxantrone transporter, MXR. GF120918 was ineffective in sensitizing MRP-overexpressing MCF-7 VP-16 cells to etoposide as determined by cytotoxicity studies. In flow cytometry experiments, rhodamine 123 efflux in S1-B1-20 cells was decreased at GF120918...

  5. Transcriptional expression analysis of ABC efflux transporters and xenobiotic-metabolizing enzymes in the Chinese rare minnow.

    Science.gov (United States)

    Yuan, Lilai; Lv, Biping; Zha, Jinmiao; Wang, Zijian

    2014-05-01

    In the present study, the cDNA fragments of five ABC transporter genes (ABCB1, ABCB11, ABCC1, ABCC2, and ABCG2) in the rare minnow were cloned, and their tissue-specific expression patterns were evaluated across eight rare minnow tissues (liver, gill, intestine, kidney, spleen, brain, skin, and muscle). Furthermore, the transcriptional effects on these ABC transporter genes and five xenobiotic-metabolizing enzyme genes (CYP1A, GSTm, GSTp1, GCLC, and UGT1a) were determined in the rare minnow liver after 12 days of pyrene exposure. Basal expression analysis showed that the tissues with high expression of the ABC transporters included the liver, kidney, and intestine. Moreover, the most highly expressed of the ABC genes were ABCB1 and ABCC2 in all eight of the tissues tested. The ABCB11 gene was almost exclusively expressed in the liver of the rare minnow, whereas ABCC1 and ABCG2 showed weak expression in all eight tissues compared to ABCB1 and ABCC2. Our results provide the first thorough examination of the expression patterns of toxicologically relevant ABC transporters in the rare minnow and serve as a necessary basis for further studies of these ABC transporters in fish. Furthermore, synergistic up-regulation of CYP1A, GSTp1, GCLC, UGT1a, and ABCC2 was observed in the rare minnow liver following pyrene exposure, while GSTm, ABCB1, ABCB11, ABCC1, and ABCG2 were not significantly affected (p ABC transporters by pyrene suggests a possible involvement and cooperation of these genes in the detoxification process in rare minnows. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Purification and biochemical characterisation of the yeast ABC transporter Pdr11p

    DEFF Research Database (Denmark)

    Laub, Katrine Rude

    Sterols constitute an essential lipid class in eukaryotic membranes where intracellular distributions are highly regulated. In the yeast Saccharomyces cerevisiae sterol uptake has been attributed to the two plasma membrane-localised ATP-binding cassette (ABC) transporters, Aus1p and Pdr11p...... understanding of their action and molecular functioning, it is helpful to focus on homogeneous preparations of membrane proteins reconstituted into model membranes like detergent micelles, liposomes, and nanodiscs. In the present study, I report the first successful expression, purification, and reconstitution...

  7. Molecular characterization of ABC transporters in marine ciliate, Euplotes crassus: Identification and response to cadmium and benzo[a]pyrene.

    Science.gov (United States)

    Kim, Hokyun; Yim, Bora; Kim, Jisoo; Kim, Haeyeon; Lee, Young-Mi

    2017-11-30

    ATP-binding cassette (ABC) transporters participate in transporting various substances, including xenobiotics, in or out of cells. However, their genetic information and function in ciliates remain still unclear. In this study, we sequenced and characterized two ABC transporter genes (EcABCB and EcABCC), and investigated the effect of cadmium (Cd) and benzo[a]pyrene (B[a]P) on their function and gene expression, using efflux assay and real-time reverse transcription-polymerase chain reaction (qRT-PCR), respectively, in the marine ciliate, Euplotes crassus. Sequencing analysis and efflux assay showed that EcABCB and EcABCC are typical ABC transporters, possessing conserved function. Exposure to Cd (≥5mg/L) and B[a]P (≥50.5μg/L) enhanced accumulation of a substrate. A significant increase in the expression of EcABCB and EcABC mRNA was observed at lower concentration in response to Cd and B[a]P. Our findings indicate that Cd and B[a]P could inhibit the efflux function of ABC transporters, leading to cellular toxicity in the ciliate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Nucleotide dependent packing differences in helical crystals of the ABC transporter MsbA.

    Science.gov (United States)

    Ward, Andrew; Mulligan, Sheila; Carragher, Bridget; Chang, Geoffrey; Milligan, Ronald A

    2009-03-01

    Bacterial ATP binding cassette (ABC) exporters fulfill a wide variety of transmembrane transport roles and are homologous to the human multidrug resistance P-glycoprotein. Recent X-ray structures of the exporters MsbA and Sav1866 have begun to describe the conformational changes that accompany the ABC transport cycle. Here we present cryo-electron microscopy structures of MsbA reconstituted into a lipid bilayer. Using ATPase inhibitors, we captured three nucleotide transition states of the transporter that were subsequently reconstituted into helical arrays. The enzyme-substrate complex (trapped by ADP-aluminum fluoride or AMPPNP) crystallized in a different helical lattice than the enzyme-product complex (trapped by ADP-vanadate). Approximately 20A resolution maps were calculated for each state and revealed MsbA to be a dimer with a large channel between the membrane spanning domains, similar to the outward facing crystal structures of MsbA and Sav1866. This suggests that while there are likely structural differences between the nucleotide transition states, membrane embedded MsbA remains in an outward facing conformation while nucleotide is bound.

  9. The Crystal Structure of the YknZ Extracellular Domain of ABC Transporter YknWXYZ from Bacillus amyloliquefaciens.

    Directory of Open Access Journals (Sweden)

    Yongbin Xu

    Full Text Available Bacillus possesses the peptide toxin Sporulation-Delaying Protein (SDP, which can kill cells within a biofilm to support continued growth, thereby delaying the onset of biofilm sporulation. The four-component transporter YknWXYZ acts as a major SDP efflux pump to protect cells against the endogenous SDP toxin, for which YknYZ is a non-canonical ATP-binding cassette (ABC-type transporter. YknYZ consists of the following two components: (1 an individual protein (YknY and (2 a respective permease (YknZ. To date, the crystal structure, molecular function, and mechanism of action of the integral membrane protein YknZ remain to be elucidated. In this study, to characterize the structural and biochemical roles of YknZ in the functional assembly of YknWXYZ, we predicted and overexpressed the YknZ extracellular domain. We determined the crystal structure of B. amyloliquefaciens YknZ at a resolution of 2.0 Å. The structure revealed that the YknZ extracellular region exhibits significant structural similarity with the MacB periplasmic domain, which is a non-canonical ABC-type transporter in the tripartite macrolide-specific efflux pump in Gram-negative bacteria. We also found that the YknZ extracellular domain can directly bind to an extracellular component of YknX. This structural and biochemical study provides insights into the assembly of YknWXYZ, which may be relevant to understanding cannibalistic peptide toxin resistance in Bacillus and controlling bacterial growth.

  10. ABC transporters P-gp and Bcrp do not limit the brain uptake of the novel antipsychotic and anticonvulsant drug cannabidiol in mice

    Directory of Open Access Journals (Sweden)

    Natalia Brzozowska

    2016-05-01

    Full Text Available Cannabidiol (CBD is currently being investigated as a novel therapeutic for the treatment of CNS disorders like schizophrenia and epilepsy. ABC transporters such as P-glycoprotein (P-gp and breast cancer resistance protein (Bcrp mediate pharmacoresistance in these disorders. P-gp and Bcrp are expressed at the blood brain barrier (BBB and reduce the brain uptake of substrate drugs including various antipsychotics and anticonvulsants. It is therefore important to assess whether CBD is prone to treatment resistance mediated by P-gp and Bcrp. Moreover, it has become common practice in the drug development of CNS agents to screen against ABC transporters to help isolate lead compounds with optimal pharmacokinetic properties. The current study aimed to assess whether P-gp and Bcrp impacts the brain transport of CBD by comparing CBD tissue concentrations in wild-type (WT mice versus mice devoid of ABC transporter genes. P-gp knockout (Abcb1a/b−∕−, Bcrp knockout (Abcg2−∕−, combined P-gp/Bcrp knockout (Abcb1a/b−∕−Abcg2−∕− and WT mice were injected with CBD, before brain and plasma samples were collected at various time-points. CBD results were compared with the positive control risperidone and 9-hydroxy risperidone, antipsychotic drugs that are established ABC transporter substrates. Brain and plasma concentrations of CBD were not greater in P-gp, Bcrp or P-gp/Bcrp knockout mice than WT mice. In comparison, the brain/plasma concentration ratios of risperidone and 9-hydroxy risperidone were profoundly higher in P-gp knockout mice than WT mice. These results suggest that CBD is not a substrate of P-gp or Bcrp and may be free from the complication of reduced brain uptake by these transporters. Such findings provide favorable evidence for the therapeutic development of CBD in the treatment of various CNS disorders.

  11. ABC transporters P-gp and Bcrp do not limit the brain uptake of the novel antipsychotic and anticonvulsant drug cannabidiol in mice.

    Science.gov (United States)

    Brzozowska, Natalia; Li, Kong M; Wang, Xiao Suo; Booth, Jessica; Stuart, Jordyn; McGregor, Iain S; Arnold, Jonathon C

    2016-01-01

    Cannabidiol (CBD) is currently being investigated as a novel therapeutic for the treatment of CNS disorders like schizophrenia and epilepsy. ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) mediate pharmacoresistance in these disorders. P-gp and Bcrp are expressed at the blood brain barrier (BBB) and reduce the brain uptake of substrate drugs including various antipsychotics and anticonvulsants. It is therefore important to assess whether CBD is prone to treatment resistance mediated by P-gp and Bcrp. Moreover, it has become common practice in the drug development of CNS agents to screen against ABC transporters to help isolate lead compounds with optimal pharmacokinetic properties. The current study aimed to assess whether P-gp and Bcrp impacts the brain transport of CBD by comparing CBD tissue concentrations in wild-type (WT) mice versus mice devoid of ABC transporter genes. P-gp knockout (Abcb1a/b (-∕-)), Bcrp knockout (Abcg2 (-∕-)), combined P-gp/Bcrp knockout (Abcb1a/b (-∕-) Abcg2 (-∕-)) and WT mice were injected with CBD, before brain and plasma samples were collected at various time-points. CBD results were compared with the positive control risperidone and 9-hydroxy risperidone, antipsychotic drugs that are established ABC transporter substrates. Brain and plasma concentrations of CBD were not greater in P-gp, Bcrp or P-gp/Bcrp knockout mice than WT mice. In comparison, the brain/plasma concentration ratios of risperidone and 9-hydroxy risperidone were profoundly higher in P-gp knockout mice than WT mice. These results suggest that CBD is not a substrate of P-gp or Bcrp and may be free from the complication of reduced brain uptake by these transporters. Such findings provide favorable evidence for the therapeutic development of CBD in the treatment of various CNS disorders.

  12. The role of ATP-binding cassette (ABC) transporters in pathogenesis and multidrug resistance of the wheat pathogen Mycosphaerella graminicola

    NARCIS (Netherlands)

    Stergiopoulos, I.

    2003-01-01

    ATP-binding cassette (ABC) transporters are membrane proteins that utilise the energy derived from the hydrolysis of ATP to drive the transport of compounds over biological membranes. They are members of one of the largest protein families to date, present in both pro- and eukaryotic

  13. Mercury toxicokinetics of the healthy human term placenta involve amino acid transporters and ABC transporters

    International Nuclear Information System (INIS)

    Straka, Elisabeth; Ellinger, Isabella; Balthasar, Christina; Scheinast, Matthias; Schatz, Jasmin; Szattler, Tamara; Bleichert, Sonja; Saleh, Leila; Knöfler, Martin; Zeisler, Harald; Hengstschläger, Markus; Rosner, Margit; Salzer, Hans; Gundacker, Claudia

    2016-01-01

    Highlights: • It is known that MeHg is able to pass the placenta and to affect fetal brain development. • Uptake and efflux transporters were examined in human primary trophoblast cells and BeWo cells. • Involvement in mercury transfer was assessed by measurement of cellular mercury content upon siRNA mediated gene knockdown. • Localization of transporters was determined by immunofluorescence microscopy. • LAT1 and rBAT at the apical membrane of the syncytiotrophoblast (STB) are involved in MeHg uptake. • MRP1 located at basal membrane of STB mediates mercury efflux. - Abstract: Background: The capacity of the human placenta to handle exogenous stressors is poorly understood. The heavy metal mercury is well-known to pass the placenta and to affect brain development. An active transport across the placenta has been assumed. The underlying mechanisms however are virtually unknown. Objectives: Uptake and efflux transporters (17 candidate proteins) assumed to play a key role in placental mercury transfer were examined for expression, localization and function in human primary trophoblast cells and the trophoblast-derived choriocarcinoma cell line BeWo. Methods: To prove involvement of the transporters, we used small interfering RNA (siRNA) and exposed cells to methylmercury (MeHg). Total mercury contents of cells were analyzed by Cold vapor-atomic fluorescence spectrometry (CV-AFS). Localization of the proteins in human term placenta sections was determined via immunofluorescence microscopy. Results: We found the amino acid transporter subunits L-type amino acid transporter (LAT)1 and rBAT (related to b 0,+ type amino acid transporter) as well as the efflux transporter multidrug resistance associated protein (MRP)1 to be involved in mercury kinetics of trophoblast cells (t-test P < 0.05). Conclusion: The amino acid transporters located at the apical side of the syncytiotrophoblast (STB) manage uptake of MeHg. Mercury conjugated to glutathione (GSH) is

  14. ABC transporters in Mycoplasma hyopneumoniae and Mycoplasma synoviae: insights into evolution and pathogenicity

    Directory of Open Access Journals (Sweden)

    Marisa Fabiana Nicolás

    2007-01-01

    Full Text Available ABC transporters represent one of the largest superfamilies of active membrane transport proteins (MTPs with a highly conserved ATPase domain that binds and hydrolyzes ATP, supplying energy for the uptake of a variety of nutrients and for the extrusion of drugs and metabolic wastes. The complete genomes of a non-pathogenic (J and pathogenic (7448 strain of Mycoplasma hyopneumoniae, as well as of a pathogenic (53 strain of Mycoplasma synoviae have been recently sequenced. A detailed study revealed a high percentage of CDSs encoding MTPs in M. hyopneumoniae strains J (13.4%, 7448 (13.8%, and in M. synoviae 53 (11.2%, and the ABC systems represented from 85.0 to 88.6% of those CDSs. Uptake systems are mainly involved in cell nutrition and some might be associated with virulence. Exporter systems include both drug and multidrug resistant systems (MDR, which may represent mechanisms of resistance to toxic molecules. No relation was found between the phylogeny of the ATPase domains and the lifestyle or pathogenicity of Mycoplasma, but several proteins, potentially useful as targets for the control of infections, were identified.

  15. Using mass spectrometry for identification of ABC transporters from Xanthomonas citri and mutants expressed in different growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Faria, J.N.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil); Paes Leme, A.F. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)

    2012-07-01

    Full text: Xanthomonas citri is a phytopathogenic bacterium that infects citrus plants causing significant losses for the economy. In our group, we have focused on the identification and characterization of ABC transport proteins of this bacterium, in order to determinate their function for growth in vitro and in vivo, during infection. ABC transporters represent one of the largest families of proteins, which transport since small molecules as ions up to oligopeptides and sugars. In prokaryotic cells many works have reported the ABC transport function in pathogenesis, resistance, biofilm formation, infectivity and DNA repair, but until our knowledge, there is no data related to these transporters and X. citri. So, In order to determinate which transporters are expressed in X. citri, we started a proteomic analysis based on mono and bi-dimensional gels associated to mass spectrometry analyses. After growing X. citri and two different mutants deleted for ssuA and nitA genes in LB and minimum media, cellular extracts were obtained and used for preparation of mono and bi-dimensional gels. Seven bands covering the expected mass of ABC transporter components (20 kDa to 50 kDa) in SDS-PAGE were cut off the gel, treated with trypsin and submitted to the MS for protein identification. The results of 2D gels were good enough and will serve as a standard for development of similar experiments in large scale. (author)

  16. Molecular insights into the mechanism of ATP-hydrolysis by the NBD of the ABC-transporter HlyB.

    Science.gov (United States)

    Hanekop, N; Zaitseva, J; Jenewein, S; Holland, I B; Schmitt, L

    2006-02-13

    The ABC-transporter HlyB is a central element of the Type I protein secretion machinery, dedicated to export the E. coli toxin HlyA in a single step across the two membranes of the cell envelope. Here, we discuss recent insights into the structure and the mechanism of ATP-hydrolysis by the NBD of HlyB. Combining structural and biochemical data, we have suggested that substrate-assisted catalysis (SAC), but not general base catalysis, is responsible for ATP-hydrolysis in this NBD and might also operate in other NBDs. Finally, the implications and advantages of SAC are discussed in the context of ATP-induced dimerization of the NBDs.

  17. Genome-Wide Identification, Characterization and Phylogenetic Analysis of ATP-Binding Cassette (ABC) Transporter Genes in Common Carp (Cyprinus carpio).

    Science.gov (United States)

    Liu, Xiang; Li, Shangqi; Peng, Wenzhu; Feng, Shuaisheng; Feng, Jianxin; Mahboob, Shahid; Al-Ghanim, Khalid A; Xu, Peng

    2016-01-01

    The ATP-binding cassette (ABC) gene family is considered to be one of the largest gene families in all forms of prokaryotic and eukaryotic life. Although the ABC transporter genes have been annotated in some species, detailed information about the ABC superfamily and the evolutionary characterization of ABC genes in common carp (Cyprinus carpio) are still unclear. In this research, we identified 61 ABC transporter genes in the common carp genome. Phylogenetic analysis revealed that they could be classified into seven subfamilies, namely 11 ABCAs, six ABCBs, 19 ABCCs, eight ABCDs, two ABCEs, four ABCFs, and 11 ABCGs. Comparative analysis of the ABC genes in seven vertebrate species including common carp, showed that at least 10 common carp genes were retained from the third round of whole genome duplication, while 12 duplicated ABC genes may have come from the fourth round of whole genome duplication. Gene losses were also observed for 14 ABC genes. Expression profiles of the 61 ABC genes in six common carp tissues (brain, heart, spleen, kidney, intestine, and gill) revealed extensive functional divergence among the ABC genes. Different copies of some genes had tissue-specific expression patterns, which may indicate some gene function specialization. This study provides essential genomic resources for future studies in common carp.

  18. The product of the ABC half-transporter gene ABCG2 (BCRP/MXR/ABCP) is expressed in the plasma membrane

    DEFF Research Database (Denmark)

    Rocchi, E; Khodjakov, A; Volk, E L

    2000-01-01

    The products of the ABC gene family can be generally classified as either full-transporters of half-transporters. Full-transporters are expressed in the plasma membrane, whereas half-transporters are usually found in intracellular membranes. Recently, an ABC half-transporter, the ABCG2 gene product...... by Western blot and immunohistochemistry. This protein is highly overexpressed in several drug-resistant cell lines and localizes predominantly to the plasma membrane, instead of to intracellular membranes as seen with all other known half-transporters. Therefore, BCRP/MXR is unique among the ABC half...

  19. The Schizosaccharomyces pombe mam1 gene encodes an ABC transporter mediating secretion of M-factor

    DEFF Research Database (Denmark)

    Christensen, P U; Davey, William John; Nielsen, O

    1997-01-01

    In the fission yeast Schizosaccharomyces pombe, cells of opposite mating type communicate via diffusible peptide pheromones prior to mating. We have cloned the S. pombe mam1 gene, which encodes a 1336-amino acid protein belonging to the ATP-binding cassette (ABC) superfamily. The mam1 gene is only...... expressed in M cells and the gene product is responsible for the secretion of the mating pheromone. M-factor, a nonapeptide that is S-farnesylated and carboxy-methylated on its C-terminal cysteine residue. The predicted Mam1 protein is highly homologous to mammalian multiple drug-resistance proteins...

  20. Identification of Residues in the Lipopolysaccharide ABC Transporter That Coordinate ATPase Activity with Extractor Function.

    Science.gov (United States)

    Simpson, Brent W; Owens, Tristan W; Orabella, Matthew J; Davis, Rebecca M; May, Janine M; Trauger, Sunia A; Kahne, Daniel; Ruiz, Natividad

    2016-10-18

    The surface of most Gram-negative bacteria is covered with lipopolysaccharide (LPS), creating a permeability barrier against toxic molecules, including many antimicrobials. To assemble LPS on their surface, Gram-negative bacteria must extract newly synthesized LPS from the inner membrane, transport it across the aqueous periplasm, and translocate it across the outer membrane. The LptA to -G proteins assemble into a transenvelope complex that transports LPS from the inner membrane to the cell surface. The Lpt system powers LPS transport from the inner membrane by using a poorly characterized ATP-binding cassette system composed of the ATPase LptB and the transmembrane domains LptFG. Here, we characterize a cluster of residues in the groove region of LptB that is important for controlling LPS transport. We also provide the first functional characterization of LptFG and identify their coupling helices that interact with the LptB groove. Substitutions at conserved residues in these coupling helices compromise both the assembly and function of the LptB 2 FG complex. Defects in LPS transport conferred by alterations in the LptFG coupling helices can be rescued by changing a residue in LptB that is adjacent to functionally important residues in the groove region. This suppression is achieved by increasing the ATPase activity of the LptB 2 FG complex. Taken together, these data identify a specific binding site in LptB for the coupling helices of LptFG that is responsible for coupling of ATP hydrolysis by LptB with LptFG function to achieve LPS extraction. Lipopolysaccharide (LPS) is synthesized at the cytoplasmic membrane of Gram-negative bacteria and transported across several compartments to the cell surface, where it forms a barrier that protects these organisms from antibiotics. The LptB 2 FG proteins form an ATP-binding cassette (ABC) transporter that uses energy from ATP hydrolysis in the cytoplasm to facilitate extraction of LPS from the outer face of the

  1. ABC- and SLC-Transporters in Murine and Bovine Mammary Epithelium--Effects of Prochloraz.

    Directory of Open Access Journals (Sweden)

    Yagmur Yagdiran

    Full Text Available Some chemicals are ligands to efflux transporters which may result in high concentrations in milk. Limited knowledge is available on the influence of maternal exposure to chemicals on the expression and function of transporters in the lactating mammary gland. We determined gene expression of ABC and SLC transporters in murine mammary tissue of different gestation and lactation stages, in murine mammary cells (HC11 featuring resting and secreting phenotypes and in bovine mammary tissue and cells (BME-UV. Effects on transporter expression and function of the imidazole fungicide prochloraz, previously reported to influence BCRP in mammary cells, was investigated on transporter expression and function in the two cell lines. Transporters studied were BCRP, MDR1, MRP1, OATP1A5/OATP1A2, OCTN1 and OCT1. Gene expressions of BCRP and OCT1 in murine mammary glands were increased during gestation and lactation, whereas MDR1, MRP1, OATP1A5 and OCTN1 were decreased, compared to expressions in virgins. All transporters measured in mammary glands of mice were detected in bovine mammary tissue and in HC11 cells, while only MDR1 and MRP1 were detected in BME-UV cells. Prochloraz treatment induced MDR1 gene and protein expression in both differentiated HC11 and BME-UV cells and increased protein function in HC11 cells, resulting in decreased accumulation of the MDR1 substrate digoxin. In conclusion, our results demonstrate that murine (HC11 and bovine (BME-UV mammary epithelial cells can be applied to characterize expression and function of transporters as well as effects of contaminants on the mammary transporters. An altered expression, induced by a drug or toxic chemical, on any of the transporters expressed in the mammary epithelial cells during lactation may modulate the well-balanced composition of nutrients and/or secretion of contaminants in milk with potential adverse effects on breast-fed infants and dairy consumers.

  2. Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Svenningsen, Katrine; Almind Knudsen, Lina

    2015-01-01

    AIM: To evaluate ATP-binding cassette (ABC) transporters in colonic pathophysiology as they had recently been related to colorectal cancer (CRC) development. METHODS: Literature search was conducted on PubMed using combinations of the following terms: ABC transporters, ATP binding cassette....../Mdr1a, abcc2/Mrp2, abcg2/Bcrp, knock-out mice, tight junction, membrane lipid function. RESULTS: Recently, human studies reported that changes in the levels of ABC transporters were early events in the adenoma-carcinoma sequence leading to CRC. A link between ABCB1, high fat diet and gut microbes...... translocation from one side to the other of the cell membrane lipid bilayer by ABC transporters affecting inflammatory response and/or function of tight junctions, phagocytosis and vesicle trafficking. Also, diet and microbes give rise to molecules which are potential substrates for the ABC transporters...

  3. Investigation of the quaternary structure of an ABC transporter in living cells using spectrally resolved resonance energy transfer

    Science.gov (United States)

    Singh, Deo Raj

    Forster resonance energy transfer (FRET) has become an important tool to study proteins inside living cells. It has been used to explore membrane protein folding and dynamics, determine stoichiometry and geometry of protein complexes, and measure the distance between two molecules. In this dissertation, we use a method based on FRET and optical micro-spectroscopy (OptiMiS) technology, developed in our lab, to probe the structure of dynamic (as opposed to static) protein complexes in living cells. We use this method to determine the association stoichiometry and quaternary structure of an ABC transporter in living cells. Specifically, the transporter we investigate originates from the pathogen Pseudomonas aeruginosa, which is a Gram-negative bacterium with several virulence factors, lipopolysaccharides being one of them. This pathogen coexpresses two unique forms of lipopolysaccharides on its surface, the A- and B-bands. The A-band polysaccharides, synthesized in the cytoplasm, are translocated into the periplasm through an ATP-binding-cassette (ABC) transporter consisting of a transmembranar protein, Wzm, and a nucleotide-binding protein, Wzt. In P. aeruginosa, all of the biochemical studies of A-band LPS are concentrated on the stages of the synthesis and ligation of polysaccharides (PSs), leaving the export stage involving ABC transporter unexplored. The mode of PS export through ABC transporters is still unknown. This difficulty is due to the lack of information about sub-unit composition and structure of this bi-component ABC transporter. Using the FRET-OptiMiS combination method developed by our lab, we found that Wzt forms a rhombus-shaped homo-tetramer which becomes a square upon co-expression with Wzm, and that Wzm forms a square-shaped homo-tetramer both in the presence and absence of Wzt. Based on these results, we propose a structural model for the double-tetramer complex formed by the bi-component ABC transporter in living cells. An understanding of the

  4. Specificity of the second binding protein of the peptide ABC-transporter (Dpp) of Lactococcus lactis IL1403

    NARCIS (Netherlands)

    Sanz, Y; Toldra, F; Renault, P; Poolman, B

    2003-01-01

    The genome sequence of Lactococcus lactis IL1403 revealed the presence of a putative peptide-binding protein-dependent ABC-transporter (Dpp). The genes for two peptide-binding proteins (dppA and dppP) precede the membrane components, which include two transmembrane protein genes (dppB and dppC) and

  5. Human and Rat ABC Transporter Efflux of Bisphenol A and Bisphenol A Glucuronide: Interspecies Comparison and Implications for Pharmacokinetic Assessment

    Science.gov (United States)

    Significant interspecies differences exist between human and rodent with respect to absorption, distribution, and excretion of bisphenol A (BPA) and its primary metabolite, BPA-glucuronide (BPA-G). ATP-Binding Cassette (ABC) transporter enzymes play important roles in these physi...

  6. The substrate-binding protein in bacterial ABC transporters: dissecting roles in the evolution of substrate specificity.

    Science.gov (United States)

    Maqbool, Abbas; Horler, Richard S P; Muller, Axel; Wilkinson, Anthony J; Wilson, Keith S; Thomas, Gavin H

    2015-10-01

    ATP-binding cassette (ABC) transporters, although being ubiquitous in biology, often feature a subunit that is limited primarily to bacteria and archaea. This subunit, the substrate-binding protein (SBP), is a key determinant of the substrate specificity and high affinity of ABC uptake systems in these organisms. Most prokaryotes have many SBP-dependent ABC transporters that recognize a broad range of ligands from metal ions to amino acids, sugars and peptides. Herein, we review the structure and function of a number of more unusual SBPs, including an ABC transporter involved in the transport of rare furanose forms of sugars and an SBP that has evolved to specifically recognize the bacterial cell wall-derived murein tripeptide (Mtp). Both these examples illustrate that subtle changes in binding-site architecture, including changes in side chains not directly involved in ligand co-ordination, can result in significant alteration of substrate range in novel and unpredictable ways. © 2015 Authors; published by Portland Press Limited.

  7. An ABC transporter controls export of a Drosophila germ cell attractant.

    Science.gov (United States)

    Ricardo, Sara; Lehmann, Ruth

    2009-02-13

    Directed cell migration, which is critical for embryonic development, leukocyte trafficking, and cell metastasis, depends on chemoattraction. 3-hydroxy-3-methylglutaryl coenzyme A reductase regulates the production of an attractant for Drosophila germ cells that may itself be geranylated. Chemoattractants are commonly secreted through a classical, signal peptide-dependent pathway, but a geranyl-modified attractant would require an alternative pathway. In budding yeast, pheromones produced by a-cells are farnesylated and secreted in a signal peptide-independent manner, requiring the adenosine triphosphate-binding cassette (ABC) transporter Ste6p. Here we show that Drosophila germ cell migration uses a similar pathway, demonstrating that invertebrate germ cells, like yeast cells, are attracted to lipid-modified peptides. Components of this unconventional export pathway are highly conserved, suggesting that this pathway may control the production of similarly modified chemoattractants in organisms ranging from yeast to humans.

  8. Genetic variation in ABC transporter A1 contributes to HDL cholesterol in the general population

    DEFF Research Database (Denmark)

    Frikke-Schmidt, Ruth; Nordestgaard, Børge G; Jensen, Gorm B

    2004-01-01

    or single-nucleotide polymorphisms (SNPs) in ABCA1 were overrepresented in individuals with the lowest 1% (n=95) or highest 1% (n=95) HDL-C levels in the general population by screening the core promoter and coding region of ABCA1. For all nonsynonymous SNPs identified, we determined the effect of genotype......Homozygosity for mutations in ABC transporter A1 (ABCA1) causes Tangier disease, a rare HDL-deficiency syndrome. Whether heterozygosity for genetic variation in ABCA1 also contributes to HDL cholesterol (HDL-C) levels in the general population is presently unclear. We determined whether mutations...... on lipid traits in 9,259 individuals from the general population. Heterozygosity for ABCA1 mutations was identified in 10% of individuals with low HDL-C only. Three of 6 nonsynonymous SNPs (V771M, V825I, and R1587K) were associated with increases or decreases in HDL-C in women in the general population...

  9. Inhibition of the Human ABC Efflux Transporters P-gp and ...

    Science.gov (United States)

    High body burdens of polybrominated diphenyl ethers (PBDEs) in infants and young children have led to increased concern over their potential impact on human development. PBDE exposure can alter the expression of genes involved in thyroid homeostasis, including those of ATP-binding cassette (ABC) transporters, which mediate cellular xenobiotic efflux. However, little information exists on how PBDEs interact with ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). The purpose of this study was to evaluate the interactions of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and its hydroxylated metabolite 6-OH-BDE-47 with P-gp and BCRP, using human MDR1- and BCRP-expressing membrane vesicles and stably transfected NIH-3T3-MDR1 and MDCK-BCRP cells. In P-gp membranes, BDE-47 did not affect P-gp activity; however, 6-OH-BDE-47 inhibited P-gp activity at low µM concentrations (IC50 = 11.7 µM). In BCRP membranes, BDE-47 inhibited BCRP activity; however, 6-OH-BDE-47 was a stronger inhibitor [IC50 = 45.9 µM (BDE-47) vs. IC50 = 9.4 µM (6-OH-BDE-47)]. Intracellular concentrations of known P-gp and BCRP substrates [(3H)-paclitaxel and (3H)-prazosin, respectively] were significantly higher (indicating less efflux) in NIH-3T3-MDR1 and MDCK-BCRP cells in the presence of 6-OH-BDE-47, but not BDE-47. Collectively, our results indicate that the BDE-47 metabolite 6-OH-BDE-47 is an inhibitor of both P-gp and BCRP efflux activity.

  10. The ABC transporter Rv1272c of Mycobacterium tuberculosis enhances the import of long-chain fatty acids in Escherichia coli.

    Science.gov (United States)

    Martin, Audrey; Daniel, Jaiyanth

    2018-02-05

    Mycobacterium tuberculosis (Mtb), which causes tuberculosis, is capable of accumulating triacylglycerol (TAG) by utilizing fatty acids from host cells. ATP-binding cassette (ABC) transporters are involved in transport processes in all organisms. Among the classical ABC transporters in Mtb none have been implicated in fatty acid import. Since the transport of fatty acids from the host cell is important for dormancy-associated TAG synthesis in the pathogen, mycobacterial ABC transporter(s) could potentially be involved in this process. Based on sequence identities with a bacterial ABC transporter that mediates fatty acid import for TAG synthesis, we identified Rv1272c, a hitherto uncharacterized ABC-transporter in Mtb that also shows sequence identities with a plant ABC transporter involved in fatty acid transport. We expressed Rv1272c in E. coli and show that it enhances the import of radiolabeled fatty acids. We also show that Rv1272c causes a significant increase in the metabolic incorporation of radiolabeled long-chain fatty acids into cardiolipin, a tetra-acylated phospholipid, and phosphatidylglycerol in E. coli. This is the first report on the function of Rv1272c showing that it displays a long-chain fatty acid transport function. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. The Schizosaccharomyces pombe mam1 gene encodes an ABC transporter mediating secretion of M-factor

    DEFF Research Database (Denmark)

    Christensen, P U; Davey, William John; Nielsen, O

    1997-01-01

    In the fission yeast Schizosaccharomyces pombe, cells of opposite mating type communicate via diffusible peptide pheromones prior to mating. We have cloned the S. pombe mam1 gene, which encodes a 1336-amino acid protein belonging to the ATP-binding cassette (ABC) superfamily. The mam1 gene is only...... expressed in M cells and the gene product is responsible for the secretion of the mating pheromone. M-factor, a nonapeptide that is S-farnesylated and carboxy-methylated on its C-terminal cysteine residue. The predicted Mam1 protein is highly homologous to mammalian multiple drug-resistance proteins...... and to the Saccharomyces cerevisiae STE6 gene product, which mediates export of a-factor mating pheromone. We show that STE6 can also mediate secretion of M-factor in S. pombe....

  12. Enterococcus faecalis Uses a Phosphotransferase System Permease and a Host Colonization-Related ABC Transporter for Maltodextrin Uptake.

    Science.gov (United States)

    Sauvageot, Nicolas; Mokhtari, Abdelhamid; Joyet, Philippe; Budin-Verneuil, Aurélie; Blancato, Víctor S; Repizo, Guillermo D; Henry, Céline; Pikis, Andreas; Thompson, John; Magni, Christian; Hartke, Axel; Deutscher, Josef

    2017-05-01

    Maltodextrin is a mixture of maltooligosaccharides, which are produced by the degradation of starch or glycogen. They are mostly composed of α-1,4- and some α-1,6-linked glucose residues. Genes presumed to code for the Enterococcus faecalis maltodextrin transporter were induced during enterococcal infection. We therefore carried out a detailed study of maltodextrin transport in this organism. Depending on their length (3 to 7 glucose residues), E. faecalis takes up maltodextrins either via MalT, a maltose-specific permease of the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS), or the ATP binding cassette (ABC) transporter MdxEFG-MsmX. Maltotriose, the smallest maltodextrin, is primarily transported by the PTS permease. A malT mutant therefore exhibits significantly reduced growth on maltose and maltotriose. The residual uptake of the trisaccharide is catalyzed by the ABC transporter, because a malT mdxF double mutant no longer grows on maltotriose. The trisaccharide arrives as maltotriose-6″-P in the cell. MapP, which dephosphorylates maltose-6'-P, also releases P i from maltotriose-6″-P. Maltotetraose and longer maltodextrins are mainly (or exclusively) taken up via the ABC transporter, because inactivation of the membrane protein MdxF prevents growth on maltotetraose and longer maltodextrins up to at least maltoheptaose. E. faecalis also utilizes panose and isopanose, and we show for the first time, to our knowledge, that in contrast to maltotriose, its two isomers are primarily transported via the ABC transporter. We confirm that maltodextrin utilization via MdxEFG-MsmX affects the colonization capacity of E. faecalis , because inactivation of mdxF significantly reduced enterococcal colonization and/or survival in kidneys and liver of mice after intraperitoneal infection. IMPORTANCE Infections by enterococci, which are major health care-associated pathogens, are difficult to treat due to their increasing resistance to clinically

  13. LrABCF1, a GCN-type ATP-binding cassette transporter from lilium regale, is involved in defense responses against viral and fungal pathogens

    Science.gov (United States)

    ATP-binding cassette (ABC) transporters are essential for membrane translocation in diverse biological processes, such as plant development and defense response. Here, a general control non-derepressible (GCN)-type ABC transporter gene, designated LrABCF1, was identified from Cucumber mosaic virus (...

  14. Arbuscular mycorrhiza affects nickel translocation and expression of ABC transporter and metallothionein genes in Festuca arundinacea.

    Science.gov (United States)

    Shabani, Leila; Sabzalian, Mohammad R; Mostafavi pour, Sodabeh

    2016-01-01

    Mycorrhizal fungi are key microorganisms for enhancing phytoremediation of soils contaminated with heavy metals. In this study, the effects of the arbuscular mycorrhizal fungus (AMF) Funneliformis mosseae (=Glomus mosseae) on physiological and molecular mechanisms involved in the nickel (Ni) tolerance of tall fescue (Festuca arundinacea = Schedonorus arundinaceus) were investigated. Nickel addition had a pronounced negative effect on tall fescue growth and photosynthetic pigment contents, as well as on AMF colonization. Phosphorus content increased markedly in mycorrhizal plants (M) compared to non-inoculated (NM) ones. However, no significant difference was observed in root carbohydrate content between AMF-inoculated and non-inoculated plants. For both M and NM plants, Ni concentrations in shoots and roots increased according to the addition of the metal into soil, but inoculation with F. mosseae led to significantly lower Ni translocation from roots to the aboveground parts compared to non-inoculated plants. ABC transporter and metallothionein transcripts accumulated to considerably higher levels in tall fescue plants colonized by F. mosseae than in the corresponding non-mycorrhizal plants. These results highlight the importance of mycorrhizal colonization in alleviating Ni-induced stress by reducing Ni transport from roots to shoots of tall fescue plants.

  15. Detoxification of multiple heavy metals by a half-molecule ABC transporter, HMT-1, and coelomocytes of Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Marc S Schwartz

    2010-03-01

    Full Text Available Developing methods for protecting organisms in metal-polluted environments is contingent upon our understanding of cellular detoxification mechanisms. In this regard, half-molecule ATP-binding cassette (ABC transporters of the HMT-1 subfamily are required for cadmium (Cd detoxification. HMTs have conserved structural architecture that distinguishes them from other ABC transporters and allows the identification of homologs in genomes of different species including humans. We recently discovered that HMT-1 from the simple, unicellular organism, Schizosaccharomyces pombe, SpHMT1, acts independently of phytochelatin synthase (PCS and detoxifies Cd, but not other heavy metals. Whether HMTs from multicellular organisms confer tolerance only to Cd or also to other heavy metals is not known.Using molecular genetics approaches and functional in vivo assays we showed that HMT-1 from a multicellular organism, Caenorhabditis elegans, functions distinctly from its S. pombe counterpart in that in addition to Cd it confers tolerance to arsenic (As and copper (Cu while acting independently of pcs-1. Further investigation of hmt-1 and pcs-1 revealed that these genes are expressed in different cell types, supporting the notion that hmt-1 and pcs-1 operate in distinct detoxification pathways. Interestingly, pcs-1 and hmt-1 are co-expressed in highly endocytic C. elegans cells with unknown function, the coelomocytes. By analyzing heavy metal and oxidative stress sensitivities of the coelomocyte-deficient C. elegans strain we discovered that coelomocytes are essential mainly for detoxification of heavy metals, but not of oxidative stress, a by-product of heavy metal toxicity.We established that HMT-1 from the multicellular organism confers tolerance to multiple heavy metals and is expressed in liver-like cells, the coelomocytes, as well as head neurons and intestinal cells, which are cell types that are affected by heavy metal poisoning in humans. We also showed

  16. Involvement of the carboxyl-terminal region of the yeast peroxisomal half ABC transporter Pxa2p in its interaction with Pxa1p and in transporter function.

    Directory of Open Access Journals (Sweden)

    Cheng-Yi Chuang

    Full Text Available The peroxisome is a single membrane-bound organelle in eukaryotic cells involved in lipid metabolism, including β-oxidation of fatty acids. The human genetic disorder X-linked adrenoleukodystrophy (X-ALD is caused by mutations in the ABCD1 gene (encoding ALDP, a peroxisomal half ATP-binding cassette [ABC] transporter. This disease is characterized by defective peroxisomal β-oxidation and a large accumulation of very long-chain fatty acids in brain white matter, adrenal cortex, and testis. ALDP forms a homodimer proposed to be the functional transporter, whereas the peroxisomal transporter in yeast is a heterodimer comprising two half ABC transporters, Pxa1p and Pxa2p, both orthologs of human ALDP. While the carboxyl-terminal domain of ALDP is engaged in dimerization, it remains unknown whether the same region is involved in the interaction between Pxa1p and Pxa2p.Using a yeast two-hybrid assay, we found that the carboxyl-terminal region (CT of Pxa2p, but not of Pxa1p, is required for their interaction. Further analysis indicated that the central part of the CT (designated CT2 of Pxa2p was indispensable for its interaction with the carboxyl terminally truncated Pxa1_NBD. An interaction between the CT of Pxa2p and Pxa1_NBD was not detected, but could be identified in the presence of Pxa2_NBD-CT1. A single mutation of two conserved residues (aligned with X-ALD-associated mutations at the same positions in ALDP in the CT2 of the Pxa2_NBD-CT protein impaired its interaction with Pxa1_NBD or Pxa1_NBD-CT, resulting in a mutant protein that exhibited a proteinase K digestion profile different from that of the wild-type protein. Functional analysis of these mutant proteins on oleate plates indicated that they were defective in transporter function.The CT of Pxa2p is involved in its interaction with Pxa1p and in transporter function. This concept may be applied to human ALDP studies, helping to establish the pathological mechanism for CT-related X

  17. In Vitro and Ex Vivo Model Systems to Measure ABC Transporter Activity at the Blood-Brain Barrier.

    Science.gov (United States)

    de Wit, Nienke M; Kooij, Gijs; de Vries, Helga E

    2016-01-01

    With the aging population the occurrence of central nervous system diseases such as cancer, mental disorders and neurodegenerative diseases, is expected to increase and hence, the demand for effective drugs. However, the passage of drugs across the blood-brain barrier represents a major challenge in accomplishing efficient brain delivery of therapeutic agents. This highly efficient barrier is composed of a monolayer of capillary endothelial cells supported by pericytes and astrocytic end-feet, that together effectively shield the brain from the blood. The brain microvascular endothelial cells form a physical and metabolic barrier where paracellular and transcellular transport of molecules in and out of the brain is closely regulated, allowing nutrients to pass but preventing the entry of harmful neurotoxic substances, including drugs. For this purpose brain endothelial cells express efficient efflux pumps, such as ATP binding cassette (ABC) transporters, which limit the delivery of drugs into the brain. To treat the above-mentioned chronic central nervous system disorders, it is crucial to design compounds that can pass the blood-brain barrier and thus the ABC transporters. In order to achieve this, representative models of the blood-brain barrier with predictive validity are necessary. This review discusses the current in vitro and ex vivo model systems that are used to measure ABC transporter activity in order to study potential in vivo efficacy of blood-brain barrier-drug passage.

  18. Tuning the drug efflux activity of an ABC transporter in vivo by in vitro selected DARPin binders.

    Directory of Open Access Journals (Sweden)

    Markus A Seeger

    Full Text Available ABC transporters use the energy from binding and hydrolysis of ATP to import or extrude substrates across the membrane. Using ribosome display, we raised designed ankyrin repeat proteins (DARPins against detergent solubilized LmrCD, a heterodimeric multidrug ABC exporter from Lactococcus lactis. Several target-specific DARPin binders were identified that bind to at least three distinct, partially overlapping epitopes on LmrD in detergent solution as well as in native membranes. Remarkably, functional screening of the LmrCD-specific DARPin pools in L. lactis revealed three homologous DARPins which, when generated in LmrCD-expressing cells, strongly activated LmrCD-mediated drug transport. As LmrCD expression in the cell membrane was unaltered upon the co-expression of activator DARPins, the activation is suggested to occur at the level of LmrCD activity. Consistent with this, purified activator DARPins were found to stimulate the ATPase activity of LmrCD in vitro when reconstituted in proteoliposomes. This study suggests that membrane transporters are tunable in vivo by in vitro selected binding proteins. Our approach could be of biopharmaceutical importance and might facilitate studies on molecular mechanisms of ABC transporters.

  19. Chorioamnionitis Induces a Specific Signature of Placental ABC Transporters Associated with an Increase of miR-331-5p in the Human Preterm Placenta.

    Science.gov (United States)

    do Imperio, Guinever Eustaquio; Bloise, Enrrico; Javam, Mohsen; Lye, Phetcharawan; Constantinof, Andrea; Dunk, Caroline; Dos Reis, Fernando Marcos; Lye, Stephen James; Gibb, William; Ortiga-Carvalho, Tania M; Matthews, Stephen Giles

    2018-01-01

    The ATP-binding cassette (ABC) transporters mediate drug biodisposition and immunological responses in the placental barrier. In vitro infective challenges alter expression of specific placental ABC transporters. We hypothesized that chorioamnionitis induces a distinct pattern of ABC transporter expression. Gene expression of 50 ABC transporters was assessed using TaqMan® Human ABC Transporter Array, in preterm human placentas without (PTD; n=6) or with histological chorioamnionitis (PTDC; n=6). Validation was performed using qPCR, immunohistochemistry and Western blot. MicroRNAs known to regulate P-glycoprotein (P-gp) were examined by qPCR. Up-regulation of ABCB9, ABCC2 and ABCF2 mRNA was detected in chorioamnionitis (pABC transporters will likely lead to modified transport of clinically relevant compounds at the inflamed placenta. A better understanding of the potential role of these transporters in the events surrounding PTD may also enable new strategies to be developed for prevention and treatment of PTD. © 2018 The Author(s). Published by S. Karger AG, Basel.

  20. Beyond Competitive Inhibition: Regulation of ABC Transporters by Kinases and Protein-Protein Interactions as Potential Mechanisms of Drug-Drug Interactions.

    Science.gov (United States)

    Crawford, Rebecca R; Potukuchi, Praveen K; Schuetz, Erin G; Schuetz, John D

    2018-03-07

    ATP-binding cassette (ABC) transporters are transmembrane efflux transporters mediating the extrusion of an array of substrates ranging from amino acids and lipids to xenobiotics, and many therapeutic compounds, including anticancer drugs. The ABC transporters are also recognized as important contributors to pharmacokinetics, especially in drug-drug interactions and adverse drug effects. Drugs and xenobiotics, as well as pathological conditions, can influence the transcription of ABC transporters, or modify their activity or intracellular localization. Kinases can affect the aforementioned processes for ABC transporters as do protein interactions. In this review, we focus on the ABC transporters ABCB1, ABCB11, ABCC1, ABCC4 and ABCG2 and illustrate how kinases and protein-protein interactions affect these transporters. The clinical relevance of these factors is currently unknown, however these examples suggest that our understanding of drug-drug interactions will benefit from further knowledge of how kinases and protein-protein interactions affect ABC transporters. The American Society for Pharmacology and Experimental Therapeutics.

  1. Co-Induction of a Glutathione-S-transferase, a Glutathione Transporter and an ABC Transporter in Maize by Xenobiotics

    Science.gov (United States)

    Liu, Zhiqian; Song, Xiaoyu; Li, Xuefeng; Wang, Chengju

    2012-01-01

    Glutathione conjugation reactions are one of the principal mechanisms that plants utilize to detoxify xenobiotics. The induction by four herbicides (2,4-D, atrazine, metolachlor and primisulfuron) and a herbicide safener (dichlormid) on the expression of three genes, ZmGST27, ZmGT1 and ZmMRP1, encoding respectively a glutathione-S-transferase, a glutathione transporter and an ATP-binding cassette (ABC) transporter was studied in maize. The results demonstrate that the inducing effect on gene expression varies with both chemicals and genes. The expression of ZmGST27 and ZmMRP1 was up-regulated by all five compounds, whereas that of ZmGT1 was increased by atrazine, metolachlor, primisulfuron and dichlormid, but not by 2,4-D. For all chemicals, the inducing effect was first detected on ZmGST27. The finding that ZmGT1 is activated alongside ZmGST27 and ZmMRP1 suggests that glutathione transporters are an important component in the xenobiotic detoxification system of plants. PMID:22792398

  2. Quantitative structure-activity relationship (QSAR) analysis to predict drug-drug interactions of ABC transporter ABCG2.

    Science.gov (United States)

    Ishikawa, T; Hirano, H; Saito, H; Sano, K; Ikegami, Y; Yamaotsu, N; Hirono, S

    2012-06-01

    Quantitative structure-activity relationship (QSAR) analysis is a practical approach by which chemical structure is quantitatively correlated with biological activity or chemical reactivity. Human ABC transporter ABCG2 exhibits broad substrate specificity toward structurally diverse compounds. To gain insight into the relationship between the molecular structures of compounds and the interaction with ABCG2, we have developed an algorithm that analyzes QSAR to evaluate ABCG2-drug interactions. In addition, to support QSAR analysis, we developed a high-speed screening method for analyzing the drug-drug interactions of ABCG2. Based on both experimental results and computational QSAR analysis data, we propose a hypothetical mechanism underlying ABC-mediated drug transport and its interaction with drugs.

  3. Evolution of mal ABC transporter operons in the Thermococcales and Thermotogales

    Directory of Open Access Journals (Sweden)

    Gogarten J Peter

    2008-01-01

    Full Text Available Abstract Background The mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry. Results We demonstrate that the two maltose ATP binding cassette (ABC transporter operons now found in Tc. litoralis and P. furiosus (termed mal and mdx genes, respectively are not closely related to one another. The Tc. litoralis and P. furiosus mal genes are most closely related to bacterial mal genes while their respective mdx genes are archaeal. The genes of the two mal operons in Tt. maritima are not related to genes in either of these archaeal operons. They are highly similar to one another and belong to a phylogenetic lineage that includes mal genes from the enteric bacteria. A unique domain of the enteric MalF membrane spanning proteins found also in these Thermotogales MalF homologs supports their relatively close relationship with these enteric proteins. Analyses of genome sequence data from other Thermotogales species, Fervidobacterium nodosum, Thermosipho melanesiensis, Thermotoga petrophila, Thermotoga lettingae, and Thermotoga neapolitana, revealed a third apparent mal operon, absent from the published genome sequence of Tt. maritima strain MSB8. This third operon, mal3, is more closely related to the Thermococcales' bacteria-derived mal genes than are mal1 and mal2. F. nodosum, Ts. melanesiensis, and Tt. lettingae have only one of the mal1-mal2 paralogs. The mal2 operon from an unknown species of Thermotoga appears to

  4. Survey of ABC transporter and metallothionein genes expressions in tall fescue inoculated with Funneliformis intraradices under Nickel toxicity

    Directory of Open Access Journals (Sweden)

    Massomeh Rafiei-Demneh

    2016-09-01

    Full Text Available In plants, there are complex network of transport, chelation, and sequestration processes that functions in maintaining concentrations of essential metal ions in different cellular compartments, thus minimizing the damage caused by entry of non-essential metal ions into the cytosol. In the presence of toxic ones, arbuscular mycorrhizal (AM fungi are able to alleviate metal toxicity in the plant. In this study the effect of an arbuscular mycorrhizal fungi Funneliformis intraradices on growth, Nickel tolerance, and ABC transporter and metallothionein expression in leaves and roots of tall fescue (Festuca arundinacea plants cultivated in Ni polluted soil were evaluated. The fungi infected (M+ and uninfected (M- fescue plants were cultivated in soil under different Ni concentrations (0, 30, 90 and 180 ppm for 3 months. Results demonstrated the positive effect of fungi colonization on the increase in growth and reduction in Ni uptake (90 and 180 ppm and Ni translocation from roots to shoot of tall fescue under Ni stress. The results also demonstrated that the level of ABC transporterand metallothionein transcripts accumulation in roots was considerably higher for both M- and M+ plants compared to the control. Also, M+ plants showed less ABC and MET expression compared to the M- plants. These results demonstrated the importance of mycorrhizal colonization of F. intraradices in reduction of Ni transport from root to shoot of tall fescue which alleviates Ni-induced stress.

  5. A mutation within the extended X loop abolished substrate-induced ATPase activity of the human liver ATP-binding cassette (ABC) transporter MDR3.

    Science.gov (United States)

    Kluth, Marianne; Stindt, Jan; Dröge, Carola; Linnemann, Doris; Kubitz, Ralf; Schmitt, Lutz

    2015-02-20

    The human multidrug resistance protein 3 (MDR3/ABCB4) belongs to the ubiquitous family of ATP-binding cassette (ABC) transporters and is located in the canalicular membrane of hepatocytes. There it flops the phospholipids of the phosphatidylcholine (PC) family from the inner to the outer leaflet. Here, we report the characterization of wild type MDR3 and the Q1174E mutant, which was identified previously in a patient with progressive familial intrahepatic cholestasis type 3 (PFIC-3). We expressed different variants of MDR3 in the yeast Pichia pastoris, purified the proteins via tandem affinity chromatography, and determined MDR3-specific ATPase activity in the presence or absence of phospholipids. The ATPase activity of wild type MDR3 was stimulated 2-fold by liver PC or 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine lipids. Furthermore, the cross-linking of MDR3 with a thiol-reactive fluorophore blocked ATP hydrolysis and exhibited no PC stimulation. Similarly, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin lipids did not induce an increase of wild type MDR3 ATPase activity. The phosphate analogues beryllium fluoride and aluminum fluoride led to complete inhibition of ATPase activity, whereas orthovanadate inhibited exclusively the PC-stimulated ATPase activity of MDR3. The Q1174E mutation is located in the nucleotide-binding domain in direct proximity of the leucine of the ABC signature motif and extended the X loop, which is found in ABC exporters. Our data on the Q1174E mutant demonstrated basal ATPase activity, but PC lipids were incapable of stimulating ATPase activity highlighting the role of the extended X loop in the cross-talk of the nucleotide-binding domain and the transmembrane domain. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Active transmembrane drug transport in microgravity: a validation study using an ABC transporter model [v1; ref status: indexed, http://f1000r.es/41n

    Directory of Open Access Journals (Sweden)

    Sergi Vaquer

    2014-08-01

    Full Text Available Abstract Microgravity has been shown to influence the expression of ABC (ATP-Binding Cassette transporters in bacteria, fungi and mammals, but also to modify the activity of certain cellular components with structural and functional similarities to ABC transporters. Changes in activity of ABC transporters could lead to important metabolic disorders and undesired pharmacological effects during spaceflights. However, no current means exist to study the functionality of these transporters in microgravity. To this end, a Vesicular Transport Assay® (Solvo Biotechnology, Hungary was adapted to evaluate multi-drug resistance-associated protein 2 (MRP2 trans-membrane estradiol-17-β-glucuronide (E17βG transport activity, when activated by adenosine-tri-phosphate (ATP during parabolic flights. Simple diffusion, ATP-independent transport and benzbromarone inhibition were also evaluated. A high accuracy engineering system was designed to perform, monitor and synchronize all procedures. Samples were analysed using a validated high sensitivity drug detection protocol. Experiments were performed in microgravity during parabolic flights, and compared to 1g on ground results using identical equipment and procedures in all cases. Our results revealed that sufficient equipment accuracy and analytical sensitivity were reached to detect transport activity in both gravitational conditions. Additionally, transport activity levels of on ground samples were within commercial transport standards, proving the validity of the methods and equipment used. MRP2 net transport activity was significantly reduced in microgravity, so was signal detected in simple diffusion samples. Ultra-structural changes induced by gravitational stress upon vesicle membranes or transporters could explain the current results, although alternative explanations are possible. Further research is needed to provide a conclusive answer in this regard. Nevertheless, the present validated technology

  7. A lower isoelectric point increases signal sequence-mediated secretion of recombinant proteins through a bacterial ABC transporter.

    Science.gov (United States)

    Byun, Hyunjong; Park, Jiyeon; Kim, Sun Chang; Ahn, Jung Hoon

    2017-12-01

    Efficient protein production for industrial and academic purposes often involves engineering microorganisms to produce and secrete target proteins into the culture. Pseudomonas fluorescens has a TliDEF ATP-binding cassette transporter, a type I secretion system, which recognizes C-terminal LARD3 signal sequence of thermostable lipase TliA. Many proteins are secreted by TliDEF in vivo when recombined with LARD3, but there are still others that cannot be secreted by TliDEF even when LARD3 is attached. However, the factors that determine whether or not a recombinant protein can be secreted through TliDEF are still unknown. Here, we recombined LARD3 with several proteins and examined their secretion through TliDEF. We found that the proteins secreted via LARD3 are highly negatively charged with highly-acidic isoelectric points (pI) lower than 5.5. Attaching oligo-aspartate to lower the pI of negatively-charged recombinant proteins improved their secretion, and attaching oligo-arginine to negatively-charged proteins blocked their secretion by LARD3. In addition, negatively supercharged green fluorescent protein (GFP) showed improved secretion, whereas positively supercharged GFP did not secrete. These results disclosed that proteins' acidic pI and net negative charge are major factors that determine their secretion through TliDEF. Homology modeling for TliDEF revealed that TliD dimer forms evolutionarily-conserved positively-charged clusters in its pore and substrate entrance site, which also partially explains the pI dependence of the TliDEF-dependent secretions. In conclusion, lowering the isoelectric point improved LARD3-mediated protein secretion, both widening the range of protein targets for efficient production via secretion and signifying an important aspect of ABC transporter-mediated secretions. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Magnetic type transportation system

    International Nuclear Information System (INIS)

    Kobama, Masao.

    1981-01-01

    Purpose: To enable automatic transportation of nuclear substances with optional setting for the transportation distance, even for a long distance, facilitating the automation of the transportation and decreasing the space for the installation of a direction converging section of the transporting path. Constitution: A transporting vehicle having a pair of permanent magnets or ferromagnetic bodies mounted with a predetermined gap to each other along the transporting direction is provided in the transporting path including a bent direction change section for transporting specimens such as nuclear materials, and a plurality of driving vehicles having permanent magnets or ferromagnetic bodies for magnetically attracting the transporting vehicle from outside of the transporting path are arranged to the outside of the transporting path. At least one of the driving vehicles is made to run along the transporting direction of the transporting path by a driving mechanism incorporating running section such as an endless chain to drive the transportation vehicle, and the transporting vehicle is successively driven by each of the driving mechanisms. (Kawakami, Y.)

  9. Whole-Transcriptome Survey of the Putative ATP-Binding Cassette (ABC) Transporter Family Genes in the Latex-Producing Laticifers of Hevea brasiliensis

    Science.gov (United States)

    Zhiyi, Nie; Guijuan, Kang; Yu, Li; Longjun, Dai; Rizhong, Zeng

    2015-01-01

    The ATP-binding cassette (ABC) proteins or transporters constitute a large protein family in plants and are involved in many different cellular functions and processes, including solute transportation, channel regulation and molecular switches, etc. Through transcriptome sequencing, a transcriptome-wide survey and expression analysis of the ABC protein genes were carried out using the laticiferous latex from Hevea brasiliensis (rubber tree). A total of 46 putative ABC family proteins were identified in the H. brasiliensis latex. These consisted of 12 ‘full-size’, 21 ‘half-size’ and 13 other putative ABC proteins, and all of them showed strong conservation with their Arabidopsis thaliana counterparts. This study indicated that all eight plant ABC protein paralog subfamilies were identified in the H. brasiliensis latex, of which ABCB, ABCG and ABCI were the most abundant. Real-time quantitative reverse transcription-polymerase chain reaction assays demonstrated that gene expression of several latex ABC proteins was regulated by ethylene, jasmonic acid or bark tapping (a wound stress) stimulation, and that HbABCB15, HbABCB19, HbABCD1 and HbABCG21 responded most significantly of all to the abiotic stresses. The identification and expression analysis of the latex ABC family proteins could facilitate further investigation into their physiological involvement in latex metabolism and rubber biosynthesis by H. brasiliensis. PMID:25615936

  10. Drosophila ABC transporter mutants white, brown and scarlet have altered contents and distribution of biogenic amines in the brain.

    Science.gov (United States)

    Borycz, J; Borycz, J A; Kubów, A; Lloyd, V; Meinertzhagen, I A

    2008-11-01

    Monoamines such as dopamine, histamine and serotonin (5-HT) are widely distributed throughout the brain of the fruit fly Drosophila melanogaster, where many of their actions have been investigated. For example, histamine is released from photoreceptor synapses in the lamina neuropile of the visual system. Mutations of the genes white, an important eye pigmentation marker in fly genetics that encodes an ABC transporter, and its binding partner brown, cause neural phenotypes not readily reconciled solely with actions in eye pigmentation. We find that flies mutant for these genes, and another binding partner, scarlet, have about half the wild-type amount of histamine in the head, as well as reduced 5-HT and dopamine. These differences parallel reductions in immunoreactivity to the corresponding biogenic amines. They also correlate with the amine content of fractions after differential centrifugation of head homogenates. Thus, most of the amine is found in the vesicle-rich fraction of wild-type head homogenates, whereas it is found in the supernatant fractions from white, brown and scarlet flies. White co-expresses in lamina epithelial glia with Ebony, which conjugates histamine to beta-alanine. Histamine is then released when the conjugate is hydrolyzed in photoreceptors, by Tan. Mutant white ameliorates the effects of tan on head histamine whereas it exacerbates the effects of ebony. Our results are consistent with the proposal that histamine uptake by the epithelial glia may be white dependent. Behavioral abnormalities in white, brown and scarlet mutants could arise because aminergic neurons in the Drosophila brain have reduced amine for release.

  11. Iowa ABC connections.

    Science.gov (United States)

    2015-06-01

    For several years the Iowa Department of Transportation (DOT), Iowa State University, the Federal Highway Administration, : and several Iowa counties have been working to develop accelerated bridge construction (ABC) concepts, details, and processes....

  12. Mutational analysis of the binding affinity and transport activity for N-acetylglucosamine of the novel ABC transporter Ngc in the chitin-degrader Streptomyces olivaceoviridis.

    Science.gov (United States)

    Saito, A; Schrempf, H

    2004-06-01

    The highly differentiated bacterium Streptomyces olivaceoviridis efficiently hydrolyses chitin, a highly abundant natural polysaccharide, to low molecular weight products including N-acetylglucosamine (NAG) and N,N' -diacetylchitobiose (chitobiose). NAG is taken up by a PTS (phosphoenolpyruvate-dependent phosphotransferase system) which includes the PtsC2 protein, and via the ABC (ATP-binding cassette) transporter Ngc, which itself includes the substrate-binding protein NgcE. This is at present the only ABC transporter which is known to mediate specific uptake of NAG (K(m) 0.48 microM, V(max) 1.3 nmol/min/mg dry weight) and is competitively inhibited by chitobiose (K(i) 0.68 microM). The latter finding suggests that the Ngc system transports both NAG and chitobiose efficiently. To identify amino acid residues required for the function of NgcE, either the wild-type or one of several mutant forms of the ngcE gene was introduced into the strain S. olivaceoviridis DeltaNgcE/DeltaPtsC1/DeltaPtsC2, which lacks both functional transport systems for NAG, and chromosomal recombinants were selected. Based on the in vivo transport parameters of the recombinants, and the in vitro binding characteristics of the corresponding purified proteins, the following conclusions can be drawn. (1) Replacement of the C-terminally located residue Y396 by A (Y396A) has little effect on ligand-binding or transport parameters. The W395A mutation also induced little change in the substrate affinity in vitro, but it led in vivo to a marked increase (11 fold) in K(m), and enhanced V(max) (by 1.5 fold). (2) The amino acids Y201 and W280 both contribute (51% and 38%) to the ligand-binding capacity of NgcE. They are both very important for the in vivo function of the complete transport apparatus; strains expressing either Y201A or W280A show drastically (100 or 150 times) enhanced K(m) values. (3) The concomitant presence of either Y200 and W280 or Y201 and W280 is essential for the function of Ngc

  13. Structure and function of the universal stress protein TeaD and its role in regulating the ectoine transporter TeaABC of Halomonas elongata DSM 2581(T).

    Science.gov (United States)

    Schweikhard, Eva S; Kuhlmann, Sonja I; Kunte, Hans-Jörg; Grammann, Katrin; Ziegler, Christine M

    2010-03-16

    The halophilic bacterium Halomonas elongata takes up the compatible solute ectoine via the osmoregulated TRAP transporter TeaABC. A fourth orf (teaD) is located adjacent to the teaABC locus that encodes a putative universal stress protein (USP). By RT-PCR experiments we proved a cotranscription of teaD along with teaABC. Deletion of teaD resulted in an enhanced uptake for ectoine by the transporter TeaABC and hence a negative activity regulation of TeaABC by TeaD. A transcriptional regulation via DNA binding could be excluded. ATP binding to native TeaD was shown by HPLC, and the crystal structure of TeaD was solved in complex with ATP to a resolution of 1.9 A by molecular replacement. TeaD forms a dimer-dimer complex with one ATP molecule bound to each monomer, which has a Rossmann-like alpha/beta overall fold. Our results reveal an ATP-dependent oligomerization of TeaD, which might have a functional role in the regulatory mechanism of TeaD. USP-encoding orfs, which are located adjacent to genes encoding for TeaABC homologues, could be identified in several other organisms, and their physiological role in balancing the internal cellular ectoine pool is discussed.

  14. Investigating the dynamic nature of the ABC transporters: ABCB1 and MsbA as examples for the potential synergies of MD theory and EPR applications.

    Science.gov (United States)

    Stockner, Thomas; Mullen, Anna; MacMillan, Fraser

    2015-10-01

    ABC transporters are primary active transporters found in all kingdoms of life. Human multidrug resistance transporter ABCB1, or P-glycoprotein, has an extremely broad substrate spectrum and confers resistance against chemotherapy drug treatment in cancer cells. The bacterial ABC transporter MsbA is a lipid A flippase and a homolog to the human ABCB1 transporter, with which it partially shares its substrate spectrum. Crystal structures of MsbA and ABCB1 have been solved in multiple conformations, providing a glimpse into the possible conformational changes the transporter could be going through during the transport cycle. Crystal structures are inherently static, while a dynamic picture of the transporter in motion is needed for a complete understanding of transporter function. Molecular dynamics (MD) simulations and electron paramagnetic resonance (EPR) spectroscopy can provide structural information on ABC transporters, but the strength of these two methods lies in the potential to characterise the dynamic regime of these transporters. Information from the two methods is quite complementary. MD simulations provide an all atom dynamic picture of the time evolution of the molecular system, though with a narrow time window. EPR spectroscopy can probe structural, environmental and dynamic properties of the transporter in several time regimes, but only through the attachment sites of an exogenous spin label. In this review the synergistic effects that can be achieved by combining the two methods are highlighted, and a brief methodological background is also presented. © 2015 Authors; published by Portland Press Limited.

  15. Identification of the minimal region in lipase ABC transporter recognition domain of Pseudomonas fluorescens for secretion and fluorescence of green fluorescent protein

    Directory of Open Access Journals (Sweden)

    Park Yeonwoo

    2012-05-01

    Full Text Available Abstract Background TliA is a thermostable lipase secreted by the type 1 secretion system (T1SS of Pseudomonas fluorescens. The secretion is promoted by its secretion/chaperone domain located near the C-terminus, which is composed mainly of four Repeat-in-Toxin (RTX repeats. In order to identify the minimal region of TliA responsible for its secretion, five different copies of the secretion/chaperone domain, each involving truncated N-terminal residues and a common C-terminus, were acquired and named as lipase ABC transporter recognition domains (LARDs. Each LARD was fused to epidermal growth factor (EGF or green fluorescent protein (GFP, and the secretion of EGF-LARD or GFP-LARD fusion proteins was assessed in Escherichia coli with ABC transporter. Results Among the fusion proteins, GFP or EGF with 105-residue LARD3 was most efficiently secreted. In addition, GFP-LARD3 emitted wild type GFP fluorescence. Structurally, LARD3 had the 4 RTX repeats exposed at the N-terminus, while other LARDs had additional residues prior to them or missed some of the RTX repeats. LARD3 was both necessary and sufficient for efficient secretion and maintenance of GFP fluorescence in E. coli, which was also confirmed in P. fluorescens and P. fluorescens ▵tliA, a knock-out mutant of tliA. Conclusion LARD3 was a potent secretion signal in T1SS for its fusion flanking RTX motif, which enhanced secretion and preserved the fluorescence of GFP. LARD3-mediated secretion in E. coli or P. fluorescens will enable the development of enhanced protein manufacturing factory and recombinant microbe secreting protein of interest in situ.

  16. Diversity and evolution of ABC proteins in mycorrhiza-forming fungi

    OpenAIRE

    Kovalchuk, Andriy; Kohler, Annegret; Martin, Francis; Asiegbu, Fred O

    2015-01-01

    Abstract Background Transporter proteins are predicted to have an important role in the mycorrhizal symbiosis, due to the fact that this type of an interaction between plants and fungi requires a continuous nutrient and signalling exchange. ABC transporters are one of the large groups of transporter proteins found both in plants and in fungi. The crucial role of plant ABC transporters in the formation of the mycorrhizal symbiosis has bee...

  17. Conserved ABC Transport System Regulated by the General Stress Response Pathways of Alpha- and Gammaproteobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Herrou, Julien; Willett, Jonathan W.; Czyż, Daniel M.; Babnigg, Gyorgy; Kim, Youngchang; Crosson, Sean; Stock, Ann M.

    2016-12-19

    ABSTRACT

    type='genus-species'>Brucella abortusσE1is an EcfG family sigma factor that regulates the transcription of dozens of genes in response to diverse stress conditions and is required for maintenance of chronic infection in a mouse model. A putative ATP-binding cassette transporter operon,bab1_0223-bab1_0226, is among the most highly activated gene sets in the σE1regulon. The proteins encoded by the operon resemble quaternary ammonium-compatible solute importers but are most similar in sequence to the broadly conserved YehZYXW system, which remains largely uncharacterized. Transcription ofyehZYXWis activated by the general stress sigma factor σSintype='genus-species'>Enterobacteriaceae, which suggests a functional role for this transport system in bacterial stress response across the classestype='genus-species'>Alphaproteobacteriaandtype='genus-species'>Gammaproteobacteria. We present evidence thattype='genus-species'>B. abortusYehZYXW does not function as an importer of known compatible solutes under physiological conditions and does not contribute to the virulence defect of a σE1-null strain. The solein vitrophenotype associated with genetic disruption of this putative transport system is reduced growth in the presence of high Li+ion concentrations. A crystal structure oftype='genus-species'>B. abortusYehZ revealed a class II periplasmic binding protein fold with significant structural homology totype='genus-species'>Archaeoglobus fulgidusProX, which binds glycine betaine. However, the structure

  18. Diversity and evolution of ABC proteins in mycorrhiza-forming fungi.

    Science.gov (United States)

    Kovalchuk, Andriy; Kohler, Annegret; Martin, Francis; Asiegbu, Fred O

    2015-12-28

    Transporter proteins are predicted to have an important role in the mycorrhizal symbiosis, due to the fact that this type of an interaction between plants and fungi requires a continuous nutrient and signalling exchange. ABC transporters are one of the large groups of transporter proteins found both in plants and in fungi. The crucial role of plant ABC transporters in the formation of the mycorrhizal symbiosis has been demonstrated recently. Some of the fungal ABC transporter-encoding genes are also induced during the mycorrhiza formation. However, no experimental evidences of the direct involvement of fungal ABC transporters in this process are available so far. To facilitate the identification of fungal ABC proteins with a potential role in the establishment of the mycorrhizal symbiosis, we have performed an inventory of the ABC protein-encoding genes in the genomes of 25 species of mycorrhiza-forming fungi. We have identified, manually annotated and curated more than 1300 gene models of putative ABC protein-encoding genes. Out of those, more than 1000 models are predicted to encode functional proteins, whereas about 300 models represent gene fragments or putative pseudogenes. We have also performed the phylogenetic analysis of the identified sequences. The sets of ABC proteins in the mycorrhiza-forming species were compared to the related saprotrophic or plant-pathogenic fungal species. Our results demonstrate the high diversity of ABC genes in the genomes of mycorrhiza-forming fungi. Via comparison of transcriptomics data from different species, we have identified candidate groups of ABC transporters that might have a role in the process of the mycorrhiza formation. Results of our inventory will facilitate the identification of fungal transporters with a role in the mycorrhiza formation. We also provide the first data on ABC protein-coding genes for the phylum Glomeromycota and for orders Pezizales, Atheliales, Cantharellales and Sebacinales, contributing to

  19. Secondary metabolites inhibiting ABC transporters and reversing resistance of cancer cells and fungi to cytotoxic and antimicrobial agents

    Directory of Open Access Journals (Sweden)

    Michael eWink

    2012-04-01

    Full Text Available Fungal, bacterial and cancer cells can develop resistance against antifungal, antibacterial or anticancer agents. Mechanisms of resistance are complex and often multifactorial. Mechanisms include: 1. Activation of ABC transporters, such as P-gp, which pump out lipophilic compounds that have entered a cell, 2. Activation of cytochrome p450 oxidases which can oxidise lipophilic agents to make them more hydrophilic and accessible for conjugation reaction with glucuronic acid, sulphate or amino acids, and 3. Activation of glutathione transferase, which can conjugate xenobiotics. This review summarises the evidence that secondary metabolites of plants, such as alkaloids, phenolics and terpenoids can interfere with ABC transporters in cancer cells, parasites, bacteria and fungi. Among the active natural products several lipophilic terpenoids ( monoterpenes, diterpenes, triterpenes (including saponins, steroids (including cardiac glycosides and tetraterpenes but also some alkaloids (isoquinoline, protoberberine, quinoline, indole, monoterpene indole, and steroidal alkaloids function probably as competitive inhibitors of P-gp, MRP1 and BCRP in cancer cells, or efflux pumps in bacteria (NorA and fungi. More polar phenolics (phenolic acids, flavonoids, catechins, chalcones, xanthones, stilbenes, anthocyanins, tannins, anthraquinones, and naphthoquinones directly inhibit proteins forming several hydrogen and ionic bonds and thus disturbing the 3D structure of the transporters. The natural products may be interesting in medicine or agriculture as they can enhance the activity of active chemotherapeutics or pesticides or even reverse MDR, at least partially, of adapted and resistant cells. If these secondary metabolites are applied in combination with a cytotoxic or antimicrobial agent, they may reverse resistance in a synergistic fashion.

  20. ABC protein transport of MRI contrast agents in canalicular rat liver plasma vesicles and yeast vacuoles

    International Nuclear Information System (INIS)

    Pascolo, Lorella; Petrovic, Sinisa; Cupelli, Felicia; Bruschi, Carlo V.; Anelli, Pier Lucio; Lorusso, Vito; Visigalli, Massimo; Uggeri, Fulvio; Tiribelli, Claudio

    2001-01-01

    The mechanism of excretion into bile of hepatospecific magnetic resonance imaging (MRI) contrast media employed labeled Gd-reagents EOB.DTPA, BOPTA, B 20790 (iopanoate-linked), and B 21690 (glycocholate-linked) for measurement in rat liver canalicular plasma membrane vesicles and yeast vacuoles. The presence of ATP gave threefold greater transport of B 20790 and B 21690 than of EOB.DTPA and BOPTA. In yeast vacuoles the ATP stimulatory effect was eightfold with B 20790 and fivefold greater for B 21690, whereas in YCF1- or YLLO115w-deleted yeast cells the transport was significantly reduced and absent from double mutants, YCF1 and YLLO15w. The transport was similar in wild-type and deletant cells for B 21690; taurocholate gave 85% inhibition. These data suggest that bilary secretion of structurally related MRI agents depend on molecular structure. The findings are suggestive as of possible value for clinical diagnosis of inherited hyperbilirubinemias and other liver disorders

  1. Iowa ABC connections : [tech transfer summary].

    Science.gov (United States)

    2015-06-01

    The Iowa Department of Transportation (DOT) and other organizations have : been developing accelerated bridge construction (ABC) concepts, details, and : processes, and Iowa has come to be viewed as a national leader in the area of : ABC. However, th...

  2. The expression of superoxide dismutase (SOD) and a putative ABC transporter permease is inversely correlated during biofilm formation in Listeria monocytogenes 4b G

    Science.gov (United States)

    Little is known about the molecular basis of biofilm formation in Listeria monocytogenes. The superoxide dismutase (SOD) of the deletion mutant of lm.G_1771 gene, which encodes for a putative ABC_transporter permease, is highly expressed in biofilm. In this study, the sod gene deletion mutant delta ...

  3. X-linked adrenoleukodystrophy: very long-chain fatty acid metabolism, ABC half-transporters and the complicated route to treatment

    NARCIS (Netherlands)

    Kemp, Stephan; Wanders, Ronald J. A.

    2007-01-01

    X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene that encodes a peroxisomal membrane located ABC half-transporter named ALDP. Mutations in ALDP result in elevated levels of very long-chain fatty acids (VLCFA) and reduced VLCFA beta-oxidation in peroxisomes. The

  4. Pharmacological activation of LXR in utero directly influences ABC transporter expression and function in mice but does not affect adult cholesterol metabolism

    NARCIS (Netherlands)

    van Straten, E. M. E.; Huijkman, N. C. A.; Baller, J. F. W.; Kuipers, F.; Plosch, T.

    2008-01-01

    van Straten EM, Huijkman NC, Baller JF, Kuipers F, Plosch T. Pharmacological activation of LXR in utero directly influences ABC transporter expression and function in mice but does not affect adult cholesterol metabolism. Am J Physiol Endocrinol Metab 295: E1341-E1348, 2008. First published October

  5. Salinomycin overcomes ABC transporter-mediated multidrug and apoptosis resistance in human leukemia stem cell-like KG-1a cells

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Dominik [Research Group Molecular Neuro-Oncology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany); Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany); Daniel, Volker; Sadeghi, Mahmoud; Opelz, Gerhard [Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany); Naujokat, Cord, E-mail: cord.naujokat@med.uni-heidelberg.de [Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg (Germany)

    2010-04-16

    Leukemia stem cells are known to exhibit multidrug resistance by expression of ATP-binding cassette (ABC) transporters which constitute transmembrane proteins capable of exporting a wide variety of chemotherapeutic drugs from the cytosol. We show here that human promyeloblastic leukemia KG-1a cells exposed to the histone deacetylase inhibitor phenylbutyrate resemble many characteristics of leukemia stem cells, including expression of functional ABC transporters such as P-glycoprotein, BCRP and MRP8. Consequently, KG-1a cells display resistance to the induction of apoptosis by various chemotherapeutic drugs. Resistance to apoptosis induction by chemotherapeutic drugs can be reversed by cyclosporine A, which effectively inhibits the activity of P-glycoprotein and BCRP, thus demonstrating ABC transporter-mediated drug resistance in KG-1a cells. However, KG-1a are highly sensitive to apoptosis induction by salinomycin, a polyether ionophore antibiotic that has recently been shown to kill human breast cancer stem cell-like cells and to induce apoptosis in human cancer cells displaying multiple mechanisms of drug and apoptosis resistance. Whereas KG-1a cells can be adapted to proliferate in the presence of apoptosis-inducing concentrations of bortezomib and doxorubicin, salinomycin does not permit long-term adaptation of the cells to apoptosis-inducing concentrations. Thus, salinomycin should be regarded as a novel and effective agent for the elimination of leukemia stem cells and other tumor cells exhibiting ABC transporter-mediated multidrug resistance.

  6. Conservation of targeting but divergence in function and quality control of peroxisomal ABC transporters: an analysis using cross-kingdom expression

    NARCIS (Netherlands)

    Zhang, Xuebin; de Marcos Lousa, Carine; Schutte-Lensink, Nellie; Ofman, Rob; Wanders, Ronald J.; Baldwin, Stephen A.; Baker, Alison; Kemp, Stephan; Theodoulou, Frederica L.

    2011-01-01

    ABC (ATP-binding cassette) subfamily D transporters are found in all eukaryotic kingdoms and are known to play essential roles in mammals and plants; however, their number, organization and physiological contexts differ. Via cross-kingdom expression experiments, we have explored the conservation of

  7. Antagonistic changes in sensitivity to antifungal drugs by mutations of an important ABC transporter gene in a fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Wenjun Guan

    2010-06-01

    Full Text Available Fungal pathogens can be lethal, especially among immunocompromised populations, such as patients with AIDS and recipients of tissue transplantation or chemotherapy. Prolonged usage of antifungal reagents can lead to drug resistance and treatment failure. Understanding mechanisms that underlie drug resistance by pathogenic microorganisms is thus vital for dealing with this emerging issue. In this study, we show that dramatic sequence changes in PDR5, an ABC (ATP-binding cassette efflux transporter protein gene in an opportunistic fungal pathogen, caused the organism to become hypersensitive to azole, a widely used antifungal drug. Surprisingly, the same mutations conferred growth advantages to the organism on polyenes, which are also commonly used antimycotics. Our results indicate that Pdr5p might be important for ergosterol homeostasis. The observed remarkable sequence divergence in the PDR5 gene in yeast strain YJM789 may represent an interesting case of adaptive loss of gene function with significant clinical implications.

  8. Backbone NMR resonance assignments of the nucleotide binding domain of the ABC multidrug transporter LmrA from Lactococcus lactis in its ADP-bound state.

    Science.gov (United States)

    Hellmich, Ute A; Duchardt-Ferner, Elke; Glaubitz, Clemens; Wöhnert, Jens

    2012-04-01

    LmrA from Lactococcus lactis is a multidrug transporter and a member of the ATP binding cassette (ABC) transporter family. ABC transporters consist of a transmembrane domain (TMD) and a nucleotide binding domain (NBD). The NBD contains the highly conserved signature motifs of this transporter superfamily. In the case of LmrA, the TMD and the NBD are expressed as a single polypeptide. LmrA catalyzes the extrusion of hydrophobic compounds including antibiotics from the cell membrane at the expense of ATP hydrolysis. ATP binds to the NBD, where binding and hydrolysis induce conformational changes that lead to the extrusion of the substrate via the TMD. Here, we report the (1)H, (13)C and (15)N backbone chemical shift assignments of the isolated 263 amino acid containing NBD of LmrA in its ADP bound state.

  9. Professionsbachelorens ABC

    DEFF Research Database (Denmark)

    Svendsen, Christian Bundgaard

    2008-01-01

    På baggrund af Lars-Henrik Schmidts "Sociale ABC" og Bloom og Dreyfus' taksonomier gives der et teoretiske bud på professionsbachelorbegrebet......På baggrund af Lars-Henrik Schmidts "Sociale ABC" og Bloom og Dreyfus' taksonomier gives der et teoretiske bud på professionsbachelorbegrebet...

  10. The multidrug ABC transporter BmrC/BmrD of Bacillus subtilis is regulated via a ribosome-mediated transcriptional attenuation mechanism

    OpenAIRE

    Reilman, E.; Mars, R. A. T.; van Dijl, J. M.; Denham, Emma

    2014-01-01

    Expression of particular drug transporters in response to antibiotic pressure is a critical element in the development of bacterial multidrug resistance, and represents a serious concern for human health. To obtain a better understanding of underlying regulatory mechanisms, we have dissected the transcriptional activation of the ATP-binding cassette (ABC) transporter BmrC/BmrD of the Gram-positive model bacterium Bacillus subtilis. By using promoter-GFP fusions and live cell array technology,...

  11. The ABC transporter MalFGK2 sequesters the MalT transcription factor at the membrane in the absence of cognate substrate

    OpenAIRE

    Richet, Evelyne; Davidson, Amy L.; Joly, Nicolas

    2012-01-01

    MalK, the cytoplasmic component of the maltose ABC transporter from Escherichia coli is known to control negatively the activity of MalT, the activator of the maltose regulon, through complex formation. Here we further investigate this regulatory process by monitoring MalT activity and performing fluorescence microscopy analyses under various conditions. We establish that, under physiological conditions, the molecular entity that interacts with MalT is not free MalK, but the maltose transport...

  12. 9-Deazapurines as Broad-Spectrum Inhibitors of the ABC Transport Proteins P-Glycoprotein, Multidrug Resistance-Associated Protein 1, and Breast Cancer Resistance Protein.

    Science.gov (United States)

    Stefan, Katja; Schmitt, Sven Marcel; Wiese, Michael

    2017-11-09

    P-Glycoprotein (P-gp, ABCB1), multidrug resistance-associated protein 1 (MRP1, ABCC1), and breast cancer resistance protein (BCRP, ABCG2) are the three major ABC transport proteins conferring resistance to many structurally diverse anticancer agents, leading to the phenomenon called multidrug resistance (MDR). Much effort has been put into the development of clinically useful compounds to reverse MDR. Broad-spectrum inhibitors of ABC transport proteins can be of great use in cancers that simultaneously coexpress two or three transporters. In this work, we continued our effort to generate new, potent, nontoxic, and multiply effective inhibitors of the three major ABC transporters. The best compound was active in a very low micromolar concentration range against all three transporters and restored sensitivity toward daunorubicin (P-gp and MRP1) and SN-38 (BCRP) in A2780/ADR (P-gp), H69AR (MRP1), and MDCK II BCRP (BCRP) cells. Additionally, the compound is a noncompetitive inhibitor of daunorubicin (MRP1), calcein AM (P-gp), and pheophorbide A (BCRP) transport.

  13. Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

    NARCIS (Netherlands)

    Bhattacharjee, S.; Opstal, van E.J.; Alink, G.M.; Marcelis, A.T.M.; Zuilhof, H.; Rietjens, I.M.C.M.

    2013-01-01

    The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles

  14. Low Temperature ABC-Type Ru Atomic Layer Deposition through Consecutive Dissociative Chemisorption, Combustion, and Reduction Steps

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Junling; Elam, Jeffrey W.

    2015-07-28

    Thermal atomic layer deposition (ALD) of noble metals is frequently performed using molecular oxygen as the nonmetal precursor to effect a combustion-type chemistry at relatively high temperatures of 300 °C. Bis(ethylcyclopentadienyl)ruthenium (Ru(EtCp)2) is one of the common used metal precursors for Ru ALD. Using Ru(EtCp)2 and oxygen as reactants, Ru ALD was acheived at near 300 °C. Here, we demonstrate that Ru ALD can proceed at as low as 150 °C by using successive exposures to oxygen and hydrogen as the co-reactants. In situ quartz crystal microbalance (QCM) and quadrupole mass spectroscopy (QMS) measurements both suggest that this ABC-type ALD occurs through dissociative chemisorption, combustion, and reduction for the Ru(EtCp)2, oxygen and hydrogen steps, respectively, in a similar manner to processes using ozone and hydrogen as co-reactants reported previously. Moreover, we believe this molecular O2 and H2 based ABC-type ALD could be exploited for the ALD of other noble metals to decrease the deposition temperature and reduce oxygen impurities.

  15. YehZYXW of Escherichia coli Is a Low-Affinity, Non-Osmoregulatory Betaine-Specific ABC Transporter.

    Science.gov (United States)

    Lang, Shenhui; Cressatti, Marisa; Mendoza, Kris E; Coumoundouros, Chelsea N; Plater, Samantha M; Culham, Doreen E; Kimber, Matthew S; Wood, Janet M

    2015-09-22

    Transporter-mediated osmolyte accumulation stimulates the growth of Escherichia coli in high-osmolality environments. YehZYXW was predicted to be an osmoregulatory transporter because (1) osmotic and stationary phase induction of yehZYXW is mediated by RpoS, (2) the Yeh proteins are homologous to the components of known osmoregulatory ABC transporters (e.g., ProU of E. coli), and (3) YehZ models based on the structures of periplasmic betaine-binding proteins suggested that YehZ retains key betaine-binding residues. The betaines choline-O-sulfate, glycine betaine, and dimethylsulfoniopropionate bound YehZ and ProX with millimolar and micromolar affinities, respectively, as determined by equilibrium dialysis and isothermal titration calorimetry. The crystal structure of the YehZ apoprotein, determined at 1.5 Å resolution (PDB ID: 4WEP ), confirmed its similarity to other betaine-binding proteins. Small and nonpolar residues in the hinge region of YehZ (e.g., Gly223) pack more closely than the corresponding residues in ProX, stabilizing the apoprotein. Betaines bound YehZ-Gly223Ser an order of magnitude more tightly than YehZ, suggesting that weak substrate binding in YehZ is at least partially due to apo state stabilization. Neither ProX nor YehZ bound proline. Assays based on osmoprotection or proline auxotrophy failed to detect YehZYXW-mediated uptake of proline, betaines, or other osmolytes. However, transport assays revealed low-affinity glycine betaine uptake, mediated by YehZYXW, that was inhibited at high salinity. Thus, YehZYXW is a betaine transporter that shares substrate specificity, but not an osmoregulatory function, with homologues like E. coli ProU. Other work suggests that yehZYXW may be an antivirulence locus whose expression promotes persistent, asymptomatic bacterial infection.

  16. RCN1/OsABCG5, an ATP-binding cassette (ABC) transporter, is required for hypodermal suberization of roots in rice (Oryza sativa).

    Science.gov (United States)

    Shiono, Katsuhiro; Ando, Miho; Nishiuchi, Shunsaku; Takahashi, Hirokazu; Watanabe, Kohtaro; Nakamura, Motoaki; Matsuo, Yuichi; Yasuno, Naoko; Yamanouchi, Utako; Fujimoto, Masaru; Takanashi, Hideki; Ranathunge, Kosala; Franke, Rochus B; Shitan, Nobukazu; Nishizawa, Naoko K; Takamure, Itsuro; Yano, Masahiro; Tsutsumi, Nobuhiro; Schreiber, Lukas; Yazaki, Kazufumi; Nakazono, Mikio; Kato, Kiyoaki

    2014-10-01

    Suberin is a complex polymer composed of aliphatic and phenolic compounds. It is a constituent of apoplastic plant interfaces. In many plant species, including rice (Oryza sativa), the hypodermis in the outer part of roots forms a suberized cell wall (the Casparian strip and/or suberin lamellae), which inhibits the flow of water and ions and protects against pathogens. To date, there is no genetic evidence that suberin forms an apoplastic transport barrier in the hypodermis. We discovered that a rice reduced culm number1 (rcn1) mutant could not develop roots longer than 100 mm in waterlogged soil. The mutated gene encoded an ATP-binding cassette (ABC) transporter named RCN1/OsABCG5. RCN1/OsABCG5 gene expression in the wild type was increased in most hypodermal and some endodermal roots cells under stagnant deoxygenated conditions. A GFP-RCN1/OsABCG5 fusion protein localized at the plasma membrane of the wild type. Under stagnant deoxygenated conditions, well suberized hypodermis developed in wild types but not in rcn1 mutants. Under stagnant deoxygenated conditions, apoplastic tracers (periodic acid and berberine) were blocked at the hypodermis in the wild type but not in rcn1, indicating that the apoplastic barrier in the mutant was impaired. The amount of the major aliphatic suberin monomers originating from C(28) and C(30) fatty acids or ω-OH fatty acids was much lower in rcn1 than in the wild type. These findings suggest that RCN1/OsABCG5 has a role in the suberization of the hypodermis of rice roots, which contributes to formation of the apoplastic barrier. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  17. Cholestasis: The ABCs of Cellular Mechanisms for Impaired Bile Secretion – Transporters and Genes

    Directory of Open Access Journals (Sweden)

    Eldon A Shaffer

    2002-01-01

    Full Text Available The transport of bile salts, organic anions and cations, bilirubin and other substances from the portal blood into the biliary system is accomplished through the action of an array of transporter proteins in the hepatocyte. Transporters on the basolateral membrane, which faces the space of Disse, are responsible for the uptake of bile salts and organic anions. Once translocated through the hepatocyte to the canalicular membrane, other ATP pumps provide the energy to export bile salts, phospholipids and organic ions into the bile. Canalicular transport is rate limiting. Defects in specific canalicular transporters are responsible for many of the intrahepatic cholestatic syndromes that occur in children and adults. Moreover, cholestasis provokes changes in several transport mechanisms, many of which appear to be compensatory and serve to protect the liver from the toxic effects of accumulated materials. The identification and characterization of the major transporters responsible for bile formation have yielded a more precise classification of the cholestatic syndromes of infancy and childhood, and are unlocking the molecular mechanism of acquired cholestasis in adults. This review identifies the basic physiology of bile production and the actions of the key transporters, indicates the clinical relevance and possible treatments of transport disorders, and provides an illustrative case.

  18. Ion specificity and ionic strength dependence of the osmoregulatory ABC transporter OpuA

    NARCIS (Netherlands)

    Mahmood, N. A. B. Nik; Biemans-Oldehinkel, Esther; Patzlaff, Jason S.; Schuurman-Wolters, Gea K.; Poolman, Bert

    2006-01-01

    The ATPase subunit of the osmoregulatory ATP- binding cassette transporterOpuAfrom Lactococcus lactis has a C- terminal extension, the tandem cystathionine beta- synthase ( CBS) domain, which constitutes the sensor that allows the transporter to sense and respond to osmotic stress ( Biemans-

  19. Drug trafficking in mice: In vivo functions of OATP uptake and ABC efflux transporters

    NARCIS (Netherlands)

    Iusuf, D.

    2013-01-01

    In recent years, there has been increasing attention for drug uptake transporters of the Organic Anion-Transporting Polypeptide (human OATP, mouse Oatp, gene names SLCO, Slco) superfamily. Especially the OATP1A and OATP1B subfamilies turn out to have important physiological and pharmacological

  20. Insect Resistance to Bacillus thuringiensis Toxin Cry2Ab Is Conferred by Mutations in an ABC Transporter Subfamily A Protein.

    Directory of Open Access Journals (Sweden)

    Wee Tek Tay

    2015-11-01

    Full Text Available The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g., cotton expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the

  1. The ABCs of membrane transporters in health and disease (SLC series): introduction.

    Science.gov (United States)

    Hediger, Matthias A; Clémençon, Benjamin; Burrier, Robert E; Bruford, Elspeth A

    2013-01-01

    The field of transport biology has steadily grown over the past decade and is now recognized as playing an important role in manifestation and treatment of disease. The SLC (solute carrier) gene series has grown to now include 52 families and 395 transporter genes in the human genome. A list of these genes can be found at the HUGO Gene Nomenclature Committee (HGNC) website (see www.genenames.org/genefamilies/SLC). This special issue features mini-reviews for each of these SLC families written by the experts in each field. The existing online resource for solute carriers, the Bioparadigms SLC Tables (www.bioparadigms.org), has been updated and significantly extended with additional information and cross-links to other relevant databases, and the nomenclature used in this database has been validated and approved by the HGNC. In addition, the Bioparadigms SLC Tables functionality has been improved to allow easier access by the scientific community. This introduction includes: an overview of all known SLC and "non-SLC" transporter genes; a list of transporters of water soluble vitamins; a summary of recent progress in the structure determination of transporters (including GLUT1/SLC2A1); roles of transporters in human diseases and roles in drug approval and pharmaceutical perspectives. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Classification of a Haemophilus influenzae ABC Transporter HI1470/71 through Its Cognate Molybdate Periplasmic Binding Protein, MolA

    Energy Technology Data Exchange (ETDEWEB)

    Tirado-Lee, Leidamarie; Lee, Allen; Rees, Douglas C.; Pinkett, Heather W. (CIT); (NWU)

    2014-10-02

    molA (HI1472) from H. influenzae encodes a periplasmic binding protein (PBP) that delivers substrate to the ABC transporter MolB{sub 2}C{sub 2} (formerly HI1470/71). The structures of MolA with molybdate and tungstate in the binding pocket were solved to 1.6 and 1.7 {angstrom} resolution, respectively. The MolA-binding protein binds molybdate and tungstate, but not other oxyanions such as sulfate and phosphate, making it the first class III molybdate-binding protein structurally solved. The {approx}100 {mu}M binding affinity for tungstate and molybdate is significantly lower than observed for the class II ModA molybdate-binding proteins that have nanomolar to low micromolar affinity for molybdate. The presence of two molybdate loci in H. influenzae suggests multiple transport systems for one substrate, with molABC constituting a low-affinity molybdate locus.

  3. Effects of advanced carbohydrate counting guided by an automated bolus calculator in Type 1 diabetes mellitus (StenoABC)

    DEFF Research Database (Denmark)

    Hommel, E; Schmidt, S; Vistisen, D

    2017-01-01

    AIMS: To test whether concomitant use of an automated bolus calculator for people with Type 1 diabetes carrying out advanced carbohydrate counting would induce further improvements in metabolic control. METHODS: We conducted a 12-month, randomized, parallel-group, open-label, single-centre, inves......AIMS: To test whether concomitant use of an automated bolus calculator for people with Type 1 diabetes carrying out advanced carbohydrate counting would induce further improvements in metabolic control. METHODS: We conducted a 12-month, randomized, parallel-group, open-label, single...... carbohydrate counting using mental calculations (MC group) or advanced carbohydrate counting using an automated bolus calculator (ABC group) during a 3.5-h group training course. For 12 months after training, participants attended a specialized diabetes centre quarterly. The primary outcome was change in HbA1c...... HbA1c reductions when guided by an automated bolus calculator (NCT02084498)....

  4. Development, Maintenance, and Reversal of Multiple Drug Resistance: At the Crossroads of TFPI1, ABC Transporters, and HIF1

    Directory of Open Access Journals (Sweden)

    Terra Arnason

    2015-10-01

    Full Text Available Early detection and improved therapies for many cancers are enhancing survival rates. Although many cytotoxic therapies are approved for aggressive or metastatic cancer; response rates are low and acquisition of de novo resistance is virtually universal. For decades; chemotherapeutic treatments for cancer have included anthracyclines such as Doxorubicin (DOX; and its use in aggressive tumors appears to remain a viable option; but drug resistance arises against DOX; as for all other classes of compounds. Our recent work suggests the anticoagulant protein Tissue Factor Pathway Inhibitor 1α (TFPI1α plays a role in driving the development of multiple drug resistance (MDR; but not maintenance; of the MDR state. Other factors; such as the ABC transporter drug efflux pumps MDR-1/P-gp (ABCB1 and BCRP (ABCG2; are required for MDR maintenance; as well as development. The patient population struggling with therapeutic resistance specifically requires novel treatment options to resensitize these tumor cells to therapy. In this review we discuss the development, maintenance, and reversal of MDR as three distinct phases of cancer biology. Possible means to exploit these stages to reverse MDR will be explored. Early molecular detection of MDRcancers before clinical failure has the potential to offer new approaches to fighting MDRcancer.

  5. ABC- and SLC-Transporters in Murine and Bovine Mammary Epithelium

    DEFF Research Database (Denmark)

    Yagdiran, Yagmur; Oskarsson, Agneta; Knight, Christopher H.

    2016-01-01

    and SLC transporters in murine mammary tissue of different gestation and lactation stages, in murine mammary cells (HC11) featuring resting and secreting phenotypes and in bovine mammary tissue and cells (BME-UV). Effects on transporter expression and function of the imidazole fungicide prochloraz...... and lactation, whereas MDR1, MRP1, OATP1A5 and OCTN1 were decreased, compared to expressions in virgins. All transporters measured inmammary glands of mice were detected in bovine mammary tissue and in HC11 cells, while only MDR1 and MRP1 were detected in BME-UV cells. Prochloraz treatment induced MDR1 gene...... and protein expression in both differentiated HC11 and BME-UV cells and increased protein function in HC11 cells, resulting in decreased accumulation of the MDR1substrate digoxin. In conclusion, our results demonstrate that murine (HC11) and bovine (BME-UV) mammary epithelial cells can be applied...

  6. Reversal of resistance by GF120918 in cell lines expressing the ABC half-transporter, MXR

    DEFF Research Database (Denmark)

    de Bruin, M; Miyake, K; Litman, Thomas

    1999-01-01

    -80, a subline expressing a newly identified mitoxantrone transporter, MXR. GF120918 was ineffective in sensitizing MRP-overexpressing MCF-7 VP-16 cells to etoposide as determined by cytotoxicity studies. In flow cytometry experiments, rhodamine 123 efflux in S1-B1-20 cells was decreased at GF120918...

  7. ABC Transporter Subfamily D: Distinct Differences in Behavior between ABCD1–3 and ABCD4 in Subcellular Localization, Function, and Human Disease

    Science.gov (United States)

    2016-01-01

    ATP-binding cassette (ABC) transporters are one of the largest families of membrane-bound proteins and transport a wide variety of substrates across both extra- and intracellular membranes. They play a critical role in maintaining cellular homeostasis. To date, four ABC transporters belonging to subfamily D have been identified. ABCD1–3 and ABCD4 are localized to peroxisomes and lysosomes, respectively. ABCD1 and ABCD2 are involved in the transport of long and very long chain fatty acids (VLCFA) or their CoA-derivatives into peroxisomes with different substrate specificities, while ABCD3 is involved in the transport of branched chain acyl-CoA into peroxisomes. On the other hand, ABCD4 is deduced to take part in the transport of vitamin B12 from lysosomes into the cytosol. It is well known that the dysfunction of ABCD1 results in X-linked adrenoleukodystrophy, a severe neurodegenerative disease. Recently, it is reported that ABCD3 and ABCD4 are responsible for hepatosplenomegaly and vitamin B12 deficiency, respectively. In this review, the targeting mechanism and physiological functions of the ABCD transporters are summarized along with the related disease. PMID:27766264

  8. ABC Transporter Subfamily D: Distinct Differences in Behavior between ABCD1-3 and ABCD4 in Subcellular Localization, Function, and Human Disease.

    Science.gov (United States)

    Kawaguchi, Kosuke; Morita, Masashi

    2016-01-01

    ATP-binding cassette (ABC) transporters are one of the largest families of membrane-bound proteins and transport a wide variety of substrates across both extra- and intracellular membranes. They play a critical role in maintaining cellular homeostasis. To date, four ABC transporters belonging to subfamily D have been identified. ABCD1-3 and ABCD4 are localized to peroxisomes and lysosomes, respectively. ABCD1 and ABCD2 are involved in the transport of long and very long chain fatty acids (VLCFA) or their CoA-derivatives into peroxisomes with different substrate specificities, while ABCD3 is involved in the transport of branched chain acyl-CoA into peroxisomes. On the other hand, ABCD4 is deduced to take part in the transport of vitamin B 12 from lysosomes into the cytosol. It is well known that the dysfunction of ABCD1 results in X-linked adrenoleukodystrophy, a severe neurodegenerative disease. Recently, it is reported that ABCD3 and ABCD4 are responsible for hepatosplenomegaly and vitamin B 12 deficiency, respectively. In this review, the targeting mechanism and physiological functions of the ABCD transporters are summarized along with the related disease.

  9. ABC Transporter Subfamily D: Distinct Differences in Behavior between ABCD1–3 and ABCD4 in Subcellular Localization, Function, and Human Disease

    Directory of Open Access Journals (Sweden)

    Kosuke Kawaguchi

    2016-01-01

    Full Text Available ATP-binding cassette (ABC transporters are one of the largest families of membrane-bound proteins and transport a wide variety of substrates across both extra- and intracellular membranes. They play a critical role in maintaining cellular homeostasis. To date, four ABC transporters belonging to subfamily D have been identified. ABCD1–3 and ABCD4 are localized to peroxisomes and lysosomes, respectively. ABCD1 and ABCD2 are involved in the transport of long and very long chain fatty acids (VLCFA or their CoA-derivatives into peroxisomes with different substrate specificities, while ABCD3 is involved in the transport of branched chain acyl-CoA into peroxisomes. On the other hand, ABCD4 is deduced to take part in the transport of vitamin B12 from lysosomes into the cytosol. It is well known that the dysfunction of ABCD1 results in X-linked adrenoleukodystrophy, a severe neurodegenerative disease. Recently, it is reported that ABCD3 and ABCD4 are responsible for hepatosplenomegaly and vitamin B12 deficiency, respectively. In this review, the targeting mechanism and physiological functions of the ABCD transporters are summarized along with the related disease.

  10. Downregulation of eIF4G by microRNA-503 enhances drug sensitivity of MCF-7/ADR cells through suppressing the expression of ABC transport proteins.

    Science.gov (United States)

    Pan, Xia; Yang, Xiaoyan; Zang, Jinglei; Zhang, Si; Huang, Nan; Guan, Xinxin; Zhang, Jianhua; Wang, Zhihui; Li, Xi; Lei, Xiaoyong

    2017-06-01

    Overexpression of adenosine triphosphate-binding cassette (ABC) transport protein is emerging as a critical contributor to anticancer drug resistance. The eukaryotic translation initiation factor (eIF) 4F complex, the key modulator of mRNA translation, is regulated by the phosphoinositide 3-kinase-AKT-mammalian target of rapamycin pathway in anticancer drug-resistant tumors. The present study demonstrated the roles of ABC translation protein alterations in the acquisition of the Adriamycin (ADM)-resistant phenotype of MCF-7 human breast cells. Quantitative polymerase chain reaction and western blot analysis were applied to examine the differences in mRNA and protein levels, respectively. It was found that the expression of the ABC sub-family B member 1, ABC sub-family C member 1 and ABC sub-family G member 2 transport proteins were upregulated in MCF-7/ADR cells. An MTT assay was used to detect the cell viability, from the results MCF-7/ADR cells were less sensitive to ADM, tamoxifen (TAM) and taxol (TAX) treatment compared with MCF-7 cells. We predicted that the 3'-untranslated region of eukaryotic translation initiation factor 4-γ 1 (eIF4G) contains a potential miRNA binding site for microRNA (miR)-503 through using computational programs. These binding sites were confirmed by luciferase reporter assays. eIF4G mRNA degradation was accelerated in cells transfected with miR-503 mimics. Furthermore, it was demonstrated that eIF4G and ABC translation proteins were significantly downregulated in MCF-7/ADR cells after transfection with miR-503. It was found that miR-503 mimics could sensitize the cells to treatment with ADM, TAM and TAX. These findings demonstrated for the first time that eIF4G acted as a key factor in MCF-7/ADR cells, and may be an efficient agent for preventing and reversing multi-drug resistance in breast cancer.

  11. ABC Transporters and Their Role in the Neoadjuvant Treatment of Esophageal Cancer

    Directory of Open Access Journals (Sweden)

    David Vrana

    2018-03-01

    Full Text Available The prognosis of esophageal cancer (EC is poor, despite considerable effort of both experimental scientists and clinicians. The tri-modality treatment consisting of neoadjuvant chemoradiation followed by surgery has remained the gold standard over decades, unfortunately, without significant progress in recent years. Suitable prognostic factors indicating which patients will benefit from this tri-modality treatment are missing. Some patients rapidly progress on the neoadjuvant chemoradiotherapy, which is thus useless and sometimes even harmful. At the same time, other patients achieve complete remission on neoadjuvant chemoradiotherapy and subsequent surgery may increase their risk of morbidity and mortality. The prognosis of patients ranges from excellent to extremely poor. Considering these differences, the role of drug metabolizing enzymes and transporters, among other factors, in the EC response to chemotherapy may be more important compared, for example, with pancreatic cancer where all patients progress on chemotherapy regardless of the treatment or disease stage. This review surveys published literature describing the potential role of ATP-binding cassette transporters, the genetic polymorphisms, epigenetic regulations, and phenotypic changes in the prognosis and therapy of EC. The review provides knowledge base for further research of potential predictive biomarkers that will allow the stratification of patients into defined groups for optimal therapeutic outcome.

  12. Lateral gene transfer of an ABC transporter complex between major constituents of the human gut microbiome

    Directory of Open Access Journals (Sweden)

    Meehan Conor J

    2012-11-01

    Full Text Available Abstract Background Several links have been established between the human gut microbiome and conditions such as obesity and inflammatory bowel syndrome. This highlights the importance of understanding what properties of the gut microbiome can affect the health of the human host. Studies have been undertaken to determine the species composition of this microbiome and infer functional profiles associated with such host properties. However, lateral gene transfer (LGT between community members may result in misleading taxonomic attributions for the recipient organisms, thus making species-function links difficult to establish. Results We identified a peptides/nickel transport complex whose components differed in abundance based upon levels of host obesity, and assigned the encoded proteins to members of the microbial community. Each protein was assigned to several distinct taxonomic groups, with moderate levels of agreement observed among different proteins in the complex. Phylogenetic trees of these proteins produced clusters that differed greatly from taxonomic attributions and indicated that habitat-directed LGT of this complex is likely to have occurred, though not always between the same partners. Conclusions These findings demonstrate that certain membrane transport systems may be an important factor within an obese-associated gut microbiome and that such complexes may be acquired several times by different strains of the same species. Additionally, an example of individual proteins from different organisms being transferred into one operon was observed, potentially demonstrating a functional complex despite the donors of the subunits being taxonomically disparate. Our results also highlight the potential impact of habitat-directed LGT on the resident microbiota.

  13. Control of Insulin Granule Formation and Function by the ABC Transporters ABCG1 and ABCA1 and by Oxysterol Binding Protein OSBP.

    Science.gov (United States)

    Hussain, Syed Saad; Harris, Megan T; Kreutzberger, Alex J B; Inouye, Candice M; Doyle, Catherine A; Castle, Anna M; Arvan, Peter; Castle, J David

    2018-03-14

    In pancreatic β cells, insulin granule membranes are enriched in cholesterol and are both recycled and newly generated. Cholesterol's role in supporting granule membrane formation and function is poorly understood. A TP b inding c assette transporters ABCG1 and ABCA1 regulate intracellular cholesterol and are important for insulin secretion. RNAi-induced depletion in cultured pancreatic β cells shows that ABCG1 is needed to stabilize newly made insulin granules against lysosomal degradation; ABCA1 is also involved but to a lesser extent. Both transporters are also required for optimum glucose-stimulated insulin secretion, likely via complementary roles. Exogenous cholesterol addition rescues knockdown-induced granule loss (ABCG1) and reduced secretion (both transporters). Another cholesterol transport protein, oxysterol binding protein (OSBP) appears to act proximally as a source of endogenous cholesterol for granule formation. Its knockdown caused similar defective stability of young granules and glucose-stimulated insulin secretion, neither of which were rescued with exogenous cholesterol. Dual knockdowns of OSBP and ABC transporters support their serial function in supplying and concentrating cholesterol for granule formation. OSBP knockdown also decreased proinsulin synthesis consistent with a proximal ER defect. Thus, membrane cholesterol distribution contributes to insulin homeostasis at production, packaging and export levels through the actions of OSBP and ABCs G1 and A1. © 2018 by The American Society for Cell Biology.

  14. Gene cloning and characteristics of the RND-type multidrug efflux pump MuxABC-OpmB possessing two RND components in Pseudomonas aeruginosa.

    Science.gov (United States)

    Mima, Takehiko; Kohira, Naoki; Li, Yang; Sekiya, Hiroshi; Ogawa, Wakano; Kuroda, Teruo; Tsuchiya, Tomofusa

    2009-11-01

    muxA-muxB-muxC-opmB (formerly PA2528-PA2527-PA2526-opmB), encoding a putative resistance nodulation cell division (RND)-type multidrug efflux pump system, was cloned from Pseudomonas aeruginosa PAO1. Introduction of muxABC-opmB into P. aeruginosa YM64, a drug-hypersusceptible strain, led to elevated MICs of aztreonam, macrolides, novobiocin and tetracycline. Since muxB and muxC, both of which encode RND components, were essential for function, MuxABC-OpmB is thought to be a drug efflux pump with four components. One novobiocin-resistant mutant, PMX725, isolated from P. aeruginosa PMX7 showed elevated resistance not only to novobiocin but also to aztreonam, macrolides and tetracycline. Increased mRNA expression of muxABC-opmB was observed in the mutant PMX725 compared with the parental strain. Sequencing analysis revealed that a single-nucleotide insertion had occurred in the deduced promoter region for muxABC-opmB in PMX725. In this study, we have characterized the last RND-type multidrug efflux pump predicted from the genome sequence in P. aeruginosa.

  15. Live cell FRET microscopy: homo- and heterodimerization of two human peroxisomal ABC transporters, the adrenoleukodystrophy protein (ALDP, ABCD1) and PMP70 (ABCD3).

    Science.gov (United States)

    Hillebrand, Merle; Verrier, Sophie E; Ohlenbusch, Andreas; Schäfer, Annika; Söling, Hans-Dieter; Wouters, Fred S; Gärtner, Jutta

    2007-09-14

    The adrenoleukodystrophy protein (ALDP) and the 70-kDa peroxisomal membrane protein (PMP70) are half-ATP-binding cassette (ABC) transporters in the mammalian peroxisome membrane. Mutations in the gene encoding ALDP result in a devastating neurodegenerative disorder, X-linked adrenoleukodystrophy (X-ALD) that is associated with elevated levels of very long chain fatty acids because of impaired peroxisomal beta-oxidation. The interactions of peroxisomal ABC transporters, their role in the peroxisomal membrane, and their functions in disease pathogenesis are poorly understood. Studies on ABC transporters revealed that half-transporters have to dimerize to gain functionality. So far, conflicting observations are described for ALDP. By the use of in vitro methods (yeast two-hybrid and immunoprecipitation assays) on the one hand, it was shown that ALDP can form homodimers as well as heterodimers with PMP70 and ALDR, while on the other hand, it was demonstrated that ALDP and PMP70 exclusively homodimerize. To circumvent the problems of artificial interactions due to biochemical sample preparation in vitro, we investigated protein-protein interaction of ALDP in its physiological environment by FRET microscopy in intact living cells. The statistical relevance of FRET data was determined in two different ways using probability distribution shift analysis and Kolmogorov-Smirnov statistics. We demonstrate in vivo that ALDP and PMP70 form homodimers as well as ALDP/PMP70 heterodimers where ALDP homodimers predominate. Using C-terminal deletion constructs of ALDP, we demonstrate that the last 87 C-terminal amino acids harbor the most important protein domain mediating these interactions, and that the N-terminal transmembrane region of ALDP has an additional stabilization effect on ALDP homodimers. Loss of ALDP homo- or heterodimerization is highly relevant for understanding the disease mechanisms of X-ALD.

  16. Combined phylogeny and neighborhood analysis of the evolution of the ABC transporters conferring multiple drug resistance in hemiascomycete yeasts

    Directory of Open Access Journals (Sweden)

    Goffeau André

    2009-10-01

    Full Text Available Abstract Background Pleiotropic Drug Resistant transporters (PDR are members of the ATP-Binding Cassette (ABC subfamily which export antifungals and other xenobiotics in fungi and plants. This subfamily of transmembrane transporters has nine known members in Saccharomyces cerevisiae. We have analyzed the complex evolution of the pleiotropic drug resistance proteins (Pdrp subfamily where gene duplications and deletions occur independently in individual genomes. This study was carried out on 62 Pdrp from nine hemiascomycetous species, seven of which span 6 of the 14 clades of the Saccharomyces complex while the two others species, Debaryomyces hansenii and Yarrowia lipolytica, are further apart from an evolutive point of view. Results Combined phylogenetic and neighborhood analyses enabled us to identify five Pdrp clusters in the Saccharomyces complex. Three of them comprise orthologs of the Pdrp sensu stricto, Pdr5p, Pdr10p, Pdr12p, Pdr15p, Snq2p and YNR070wp. The evolutive pathway of the orthologs of Snq2 and YNR070w is particularly complex due to a tandem gene array in Eremothecium gossypii, Kluyveromyces lactis and Saccharomyces (Lachancea kluyveri. This pathway and different cases of duplications and deletions were clarified by using a neighborhood analysis based on synteny. For the two distant species, Yarrowia lipolytica and Debaryomyces hansenii, no neighborhood evidence is available for these clusters and many homologs of Pdr5 and Pdr15 are phylogenetically assigned to species-based clusters. Two other clusters comprise the orthologs of the sensu lato Pdrp, Aus1p/Pdr11p and YOL075cp respectively. The evolutionary pathway of these clusters is simpler. Nevertheless, orthologs of these genes are missing in some species. Conclusion Numerous duplications were traced among the Hemiascomycetous Pdrp studied. The role of the Whole Genome Duplication (WGD is sorted out and our analyses confirm the common ancestrality of Pdr5p and Pdr15p. A tandem

  17. Combined phylogeny and neighborhood analysis of the evolution of the ABC transporters conferring multiple drug resistance in hemiascomycete yeasts.

    Science.gov (United States)

    Seret, Marie-Line; Diffels, Julie F; Goffeau, André; Baret, Philippe V

    2009-10-01

    Pleiotropic Drug Resistant transporters (PDR) are members of the ATP-Binding Cassette (ABC) subfamily which export antifungals and other xenobiotics in fungi and plants. This subfamily of transmembrane transporters has nine known members in Saccharomyces cerevisiae. We have analyzed the complex evolution of the pleiotropic drug resistance proteins (Pdrp) subfamily where gene duplications and deletions occur independently in individual genomes. This study was carried out on 62 Pdrp from nine hemiascomycetous species, seven of which span 6 of the 14 clades of the Saccharomyces complex while the two others species, Debaryomyces hansenii and Yarrowia lipolytica, are further apart from an evolutive point of view. Combined phylogenetic and neighborhood analyses enabled us to identify five Pdrp clusters in the Saccharomyces complex. Three of them comprise orthologs of the Pdrp sensu stricto, Pdr5p, Pdr10p, Pdr12p, Pdr15p, Snq2p and YNR070wp. The evolutive pathway of the orthologs of Snq2 and YNR070w is particularly complex due to a tandem gene array in Eremothecium gossypii, Kluyveromyces lactis and Saccharomyces (Lachancea) kluyveri. This pathway and different cases of duplications and deletions were clarified by using a neighborhood analysis based on synteny. For the two distant species, Yarrowia lipolytica and Debaryomyces hansenii, no neighborhood evidence is available for these clusters and many homologs of Pdr5 and Pdr15 are phylogenetically assigned to species-based clusters. Two other clusters comprise the orthologs of the sensu lato Pdrp, Aus1p/Pdr11p and YOL075cp respectively. The evolutionary pathway of these clusters is simpler. Nevertheless, orthologs of these genes are missing in some species. Numerous duplications were traced among the Hemiascomycetous Pdrp studied. The role of the Whole Genome Duplication (WGD) is sorted out and our analyses confirm the common ancestrality of Pdr5p and Pdr15p. A tandem gene array is observed in Eremothecium gossypii. One

  18. Association of ABC (HbA1c, blood pressure, LDL-cholesterol) goal attainment with depression and health-related quality of life among adults with type 2 diabetes.

    Science.gov (United States)

    Shah, Bijal M; Mezzio, Dylan J; Ho, Jackie; Ip, Eric J

    2015-08-01

    To determine the relationship between ABC goal attainment, depression, and health-related quality of life (HRQoL) among a national sample of patients with type 2 diabetes (T2DM). A retrospective, cross-sectional analysis was performed examining 808 non-pregnant patients ≥20 years old with T2DM from the National Health and Nutrition Examination Survey (NHANES) 2007-2012. ABC goals were defined as HbA1cABC goal attainment were examined. Overall, 23.7% of participants achieved simultaneous ABC goals. Severe depression was significantly associated with lower rates of ABC goal attainment compared to those with no depression (5.0% vs. 25.4%, p=0.048). ABC goal attainment rates were lower among females, Hispanic and non-Hispanic black minority groups, and patients with a duration of diabetes over five years, while increased visits with health care professionals were significantly associated with meeting all three ABC goals for patients with T2DM. The relationship between simultaneous ABC goal attainment, depression and HRQoL is complex. Patients with T2DM unable to meet ABC goals may benefit from increased contact with health care professionals. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Validation of inhibitors of an ABC transporter required to transport lipopolysaccharide to the cell surface in Escherichia coli

    Science.gov (United States)

    Sherman, David J.; Okuda, Suguru; Denny, William A.; Kahne, Daniel

    2013-01-01

    The presence of lipopolysaccharide (LPS) in the outer leaflet of the outer membrane (OM) of Gram-negative bacteria creates a permeability barrier that prevents the entry of most currently available antibiotics. The seven lipopolysaccharide transport (Lpt) proteins involved in transporting and assembling this glycolipid are essential for growth and division in Escherichia coli; therefore, inhibiting their functions leads to cell death. LptB, the ATPase that provides energy for LPS transport and assembly, forms a complex with three other inner membrane (IM) components, LptC, F, and G. We demonstrate that inhibitors of pure LptB can also inhibit the full IM complex, LptBFGC, purified in detergent. We also compare inhibition of LptB and the LptBFGC complex with the antibiotic activity of these compounds. Our long-term goal is to develop tools to study inhibitors of LPS biogenesis that could serve as potentiators by disrupting the OM permeability barrier, facilitating entry of clinically used antibiotics not normally used to treat Gram-negative infections, or that can serve as antibiotics themselves. PMID:23665139

  20. Phytosterols Differentially Influence ABC transporter Expression, Cholesterol Efflux and Inflammatory Cytokine Secretion in Macrophage Foam Cells

    Science.gov (United States)

    Sabeva, Nadezhda S; McPhaul, Christopher M; Li, Xiangan; Cory, Theodore J.; Feola, David J.; Graf, Gregory A

    2010-01-01

    Phytosterol supplements lower low density lipoprotein (LDL) cholesterol, but accumulate in vascular lesions of patients and limit the anti-atherosclerotic effects of LDL lowering in apolipoprotein E deficient mice, suggesting that the cholesterol lowering benefit of phytosterol supplementation may not be fully realized. Individual phytosterols have cell-type specific effects that may either be beneficial or deleterious with respect to atherosclerosis, but little is known concerning their effects on macrophage function. The effects of phytosterols on ABCA1 and ABCG1 abundance, cholesterol efflux, and inflammatory cytokine secretion were determined in cultured macrophage foam cells. Among the commonly consumed phytosterols, stigmasterol increased expression of ABCA1 and ABCG1 and increased efflux of cholesterol to apolipoprotein (Apo) AI and high density lipoprotein (HDL). Campesterol and sitosterol had no effect on ABCA1 or ABCG1 levels. Sitosterol had no effect of cholesterol efflux to Apo AI or HDL, whereas campesterol had a modest, but significant reduction in cholesterol efflux to HDL in THP-1 macrophages. Whereas stigmasterol blunted aggregated LDL-induced increases in tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β secretion, sitosterol exacerbated these effects. The presence of campesterol had no effect on agLDL-induced inflammatory cytokine secretion from THP-1 macrophages. In conclusion, the presence of stigmasterol in modified lipoproteins promoted cholesterol efflux and suppressed inflammatory cytokine secretion in response to lipid loading in macrophage foam cells. While campesterol was largely inert, the presence of sitosterol increased the proinflammatory cytokine secretion. PMID:21111593

  1. A 6-Nucleotide Regulatory Motif within the AbcR Small RNAs of Brucella abortus Mediates Host-Pathogen Interactions

    Science.gov (United States)

    Sheehan, Lauren M.

    2017-01-01

    ABSTRACT In Brucella abortus, two small RNAs (sRNAs), AbcR1 and AbcR2, are responsible for regulating transcripts encoding ABC-type transport systems. AbcR1 and AbcR2 are required for Brucella virulence, as a double chromosomal deletion of both sRNAs results in attenuation in mice. Although these sRNAs are responsible for targeting transcripts for degradation, the mechanism utilized by the AbcR sRNAs to regulate mRNA in Brucella has not been described. Here, two motifs (M1 and M2) were identified in AbcR1 and AbcR2, and complementary motif sequences were defined in AbcR-regulated transcripts. Site-directed mutagenesis of M1 or M2 or of both M1 and M2 in the sRNAs revealed transcripts to be targeted by one or both motifs. Electrophoretic mobility shift assays revealed direct, concentration-dependent binding of both AbcR sRNAs to a target mRNA sequence. These experiments genetically and biochemically characterized two indispensable motifs within the AbcR sRNAs that bind to and regulate transcripts. Additionally, cellular and animal models of infection demonstrated that only M2 in the AbcR sRNAs is required for Brucella virulence. Furthermore, one of the M2-regulated targets, BAB2_0612, was found to be critical for the virulence of B. abortus in a mouse model of infection. Although these sRNAs are highly conserved among Alphaproteobacteria, the present report displays how gene regulation mediated by the AbcR sRNAs has diverged to meet the intricate regulatory requirements of each particular organism and its unique biological niche. PMID:28588127

  2. Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

    Science.gov (United States)

    Miller, A. A.; Cao, Y.; Piro, A. L.; Blagorodnova, N.; Bue, B. D.; Cenko, S. B.; Dhawan, S.; Ferretti, R.; Fox, O. D.; Fremling, C.; Goobar, A.; Howell, D. A.; Hosseinzadeh, G.; Kasliwal, M. M.; Laher, R. R.; Lunnan, R.; Masci, F. J.; McCully, C.; Nugent, P. E.; Sollerman, J.; Taddia, F.; Kulkarni, S. R.

    2018-01-01

    Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is, when the SN could have first been detected by our survey, occurred only 0.15{+/- }0.070.15 days before our first detection. In the ∼24 hr after discovery, iPTF 16abc rose by ∼2 mag, featuring a near-linear rise in flux for ≳ 3 days. Early spectra show strong C II absorption, which disappears after ∼7 days. Unlike the extensively observed Type Ia SN 2011fe, the {(B-V)}0 colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive 56Ni in the SN ejecta, or a combination of the two. In the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.

  3. The cystic-fibrosis-associated ΔF508 mutation confers post-transcriptional destabilization on the C. elegans ABC transporter PGP-3

    Directory of Open Access Journals (Sweden)

    Liping He

    2012-11-01

    Membrane proteins make up ∼30% of the proteome. During the early stages of maturation, this class of proteins can experience localized misfolding in distinct cellular compartments, such as the cytoplasm, endoplasmic reticulum (ER lumen and ER membrane. ER quality control (ERQC mechanisms monitor folding and determine whether a membrane protein is appropriately folded or is misfolded and warrants degradation. ERQC plays crucial roles in human diseases, such as cystic fibrosis, in which deletion of a single amino acid (F508 results in the misfolding and degradation of the cystic fibrosis transmembrane conductance regulator (CFTR Cl– channel. We introduced the ΔF508 mutation into Caenorhabditis elegans PGP-3, a 12-transmembrane ABC transporter with 15% identity to CFTR. When expressed in intestinal epithelial cells, PGP-3wt was stable and efficiently trafficked to the apical plasma membrane through a COPII-dependent mechanism. However, PGP-3ΔF508 was post-transcriptionally destabilized, resulting in reduced total and apical membrane protein levels. Genetic or physiological activation of the osmotic stress response pathway, which causes accumulation of the chemical chaperone glycerol, stabilized PGP-3ΔF508. Efficient degradation of PGP-3ΔF508 required the function of several C. elegans ER-associated degradation (ERAD homologs, suggesting that destabilization occurs through an ERAD-type mechanism. Our studies show that the ΔF508 mutation causes post-transcriptional destabilization and degradation of PGP-3 in C. elegans epithelial cells. This model, combined with the power of C. elegans genetics, provides a new opportunity to genetically dissect metazoan ERQC.

  4. In Vitro Assessment of the Effect of Antiepileptic Drugs on Expression and Function of ABC Transporters and Their Interactions with ABCC2

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    Gurpreet Kaur Grewal

    2017-09-01

    Full Text Available ABC transporters have a significant role in drug disposition and response and various studies have implicated their involvement in epilepsy pharmacoresistance. Since genetic studies till now are inconclusive, we thought of investigating the role of xenobiotics as transcriptional modulators of ABC transporters. Here, we investigated the effect of six antiepileptic drugs (AEDs viz. phenytoin, carbamazepine, valproate, lamotrigine, topiramate and levetiracetam, on the expression and function of ABCB1, ABCC1, ABCC2 and ABCG2 in Caco2 and HepG2 cell lines through real time PCR, western blot and functional activity assays. Further, the interaction of AEDs with maximally induced ABCC2 was studied. Carbamazepine caused a significant induction in expression of ABCB1 and ABCC2 in HepG2 and Caco2 cells, both at the transcript and protein level, together with increased functional activity. Valproate caused a significant increase in the expression and functional activity of ABCB1 in HepG2 only. No significant effect of phenytoin, lamotrigine, topiramate and levetiracetam on the transporters under study was observed in either of the cell lines. We demonstrated the interaction of carbamazepine and valproate with ABCC2 with ATPase and 5,6-carboxyfluorescein inhibition assays. Thus, altered functionality of ABCB1 and ABCC2 can affect the disposition and bioavailability of administered drugs, interfering with AED therapy.

  5. ABC+SCM=Sant?

    OpenAIRE

    Dahl, Jonas; Porelius, Jesper

    2006-01-01

    Background: Companies of today commonly search to gain competitive advantages throughout different forms of co-operation, one of which is referred to as Supply Chain Management. Although little research has been assigned to the topic of how to manage and control this type of relation, lately a growing number of academics has been arguing that ABC is an appropriate mean of controlling this type of relationships. Purpose: The purpose of this thesis is to investigate to what degree the ongoing d...

  6. Civilsamfundets ABC

    DEFF Research Database (Denmark)

    Lund, Anker Brink; Meyer, Gitte

    Filantropiske fonde og foreninger får stadig større indflydelse på udviklingen af det danske samfund – fra kunst, kultur, byggeri og byudvikling til forskning og udvikling af den danske velfærdsstat. Gennem 32 essays giver Anker Brink Lund og Gitte Meyer en oplysende – og polemisk – analyse af de...... for almenvelllet? CIVILSAMFUNDETS ABC er skrevet på baggrund af et udredningsprojekt om civilsamfundets rolle i det danske samfund. Såvel udredningsprojektet som ABC’en er finansieret af Realdania...

  7. A 6-Nucleotide Regulatory Motif within the AbcR Small RNAs of Brucella abortus Mediates Host-Pathogen Interactions.

    Science.gov (United States)

    Sheehan, Lauren M; Caswell, Clayton C

    2017-06-06

    In Brucella abortus , two small RNAs (sRNAs), AbcR1 and AbcR2, are responsible for regulating transcripts encoding ABC-type transport systems. AbcR1 and AbcR2 are required for Brucella virulence, as a double chromosomal deletion of both sRNAs results in attenuation in mice. Although these sRNAs are responsible for targeting transcripts for degradation, the mechanism utilized by the AbcR sRNAs to regulate mRNA in Brucella has not been described. Here, two motifs (M1 and M2) were identified in AbcR1 and AbcR2, and complementary motif sequences were defined in AbcR-regulated transcripts. Site-directed mutagenesis of M1 or M2 or of both M1 and M2 in the sRNAs revealed transcripts to be targeted by one or both motifs. Electrophoretic mobility shift assays revealed direct, concentration-dependent binding of both AbcR sRNAs to a target mRNA sequence. These experiments genetically and biochemically characterized two indispensable motifs within the AbcR sRNAs that bind to and regulate transcripts. Additionally, cellular and animal models of infection demonstrated that only M2 in the AbcR sRNAs is required for Brucella virulence. Furthermore, one of the M2-regulated targets, BAB2_0612, was found to be critical for the virulence of B. abortus in a mouse model of infection. Although these sRNAs are highly conserved among Alphaproteobacteria , the present report displays how gene regulation mediated by the AbcR sRNAs has diverged to meet the intricate regulatory requirements of each particular organism and its unique biological niche. IMPORTANCE Small RNAs (sRNAs) are important components of bacterial regulation, allowing organisms to quickly adapt to changes in their environments. The AbcR sRNAs are highly conserved throughout the Alphaproteobacteria and negatively regulate myriad transcripts, many encoding ABC-type transport systems. In Brucella abortus , AbcR1 and AbcR2 are functionally redundant, as only a double abcR1 abcR2 ( abcR1 / 2 ) deletion results in attenuation in

  8. Detergent screening and purification of the human liver ABC transporters BSEP (ABCB11 and MDR3 (ABCB4 expressed in the yeast Pichia pastoris.

    Directory of Open Access Journals (Sweden)

    Philipp Ellinger

    Full Text Available The human liver ATP-binding cassette (ABC transporters bile salt export pump (BSEP/ABCB11 and the multidrug resistance protein 3 (MDR3/ABCB4 fulfill the translocation of bile salts and phosphatidylcholine across the apical membrane of hepatocytes. In concert with ABCG5/G8, these two transporters are responsible for the formation of bile and mutations within these transporters can lead to severe hereditary diseases. In this study, we report the heterologous overexpression and purification of human BSEP and MDR3 as well as the expression of the corresponding C-terminal GFP-fusion proteins in the yeast Pichia pastoris. Confocal laser scanning microscopy revealed that BSEP-GFP and MDR3-GFP are localized in the plasma membrane of P. pastoris. Furthermore, we demonstrate the first purification of human BSEP and MDR3 yielding ∼1 mg and ∼6 mg per 100 g of wet cell weight, respectively. By screening over 100 detergents using a dot blot technique, we found that only zwitterionic, lipid-like detergents such as Fos-cholines or Cyclofos were able to extract both transporters in sufficient amounts for subsequent functional analysis. For MDR3, fluorescence-detection size exclusion chromatography (FSEC screens revealed that increasing the acyl chain length of Fos-Cholines improved monodispersity. BSEP purified in n-dodecyl-β-D-maltoside or Cymal-5 after solubilization with Fos-choline 16 from P. pastoris membranes showed binding to ATP-agarose. Furthermore, detergent-solubilized and purified MDR3 showed a substrate-inducible ATPase activity upon addition of phosphatidylcholine lipids. These results form the basis for further biochemical analysis of human BSEP and MDR3 to elucidate the function of these clinically relevant ABC transporters.

  9. Detergent Screening and Purification of the Human Liver ABC Transporters BSEP (ABCB11) and MDR3 (ABCB4) Expressed in the Yeast Pichia pastoris

    Science.gov (United States)

    Stindt, Jan; Smits, Sander H. J.; Schmitt, Lutz

    2013-01-01

    The human liver ATP-binding cassette (ABC) transporters bile salt export pump (BSEP/ABCB11) and the multidrug resistance protein 3 (MDR3/ABCB4) fulfill the translocation of bile salts and phosphatidylcholine across the apical membrane of hepatocytes. In concert with ABCG5/G8, these two transporters are responsible for the formation of bile and mutations within these transporters can lead to severe hereditary diseases. In this study, we report the heterologous overexpression and purification of human BSEP and MDR3 as well as the expression of the corresponding C-terminal GFP-fusion proteins in the yeast Pichia pastoris. Confocal laser scanning microscopy revealed that BSEP-GFP and MDR3-GFP are localized in the plasma membrane of P. pastoris. Furthermore, we demonstrate the first purification of human BSEP and MDR3 yielding ∼1 mg and ∼6 mg per 100 g of wet cell weight, respectively. By screening over 100 detergents using a dot blot technique, we found that only zwitterionic, lipid-like detergents such as Fos-cholines or Cyclofos were able to extract both transporters in sufficient amounts for subsequent functional analysis. For MDR3, fluorescence-detection size exclusion chromatography (FSEC) screens revealed that increasing the acyl chain length of Fos-Cholines improved monodispersity. BSEP purified in n-dodecyl-β-D-maltoside or Cymal-5 after solubilization with Fos-choline 16 from P. pastoris membranes showed binding to ATP-agarose. Furthermore, detergent-solubilized and purified MDR3 showed a substrate-inducible ATPase activity upon addition of phosphatidylcholine lipids. These results form the basis for further biochemical analysis of human BSEP and MDR3 to elucidate the function of these clinically relevant ABC transporters. PMID:23593265

  10. A burst of ABC genes in the genome of the polyphagous spider mite Tetranychus urticae

    NARCIS (Netherlands)

    Dermauw, W.; Osborne, E.J.; Clark, R.M.; Grbić, M.; Tirry, L.; Van Leeuwen, T.

    2013-01-01

    Background: The ABC (ATP-binding cassette) gene superfamily is widespread across all living species. The majority of ABC genes encode ABC transporters, which are membrane-spanning proteins capable of transferring substrates across biological membranes by hydrolyzing ATP. Although ABC transporters

  11. Classification of E-Nose Aroma Data of Four Fruit Types by ABC-Based Neural Network

    Directory of Open Access Journals (Sweden)

    M. Fatih Adak

    2016-02-01

    Full Text Available Electronic nose technology is used in many areas, and frequently in the beverage industry for classification and quality-control purposes. In this study, four different aroma data (strawberry, lemon, cherry, and melon were obtained using a MOSES II electronic nose for the purpose of fruit classification. To improve the performance of the classification, the training phase of the neural network with two hidden layers was optimized using artificial bee colony algorithm (ABC, which is known to be successful in exploration. Test data were given to two different neural networks, each of which were trained separately with backpropagation (BP and ABC, and average test performances were measured as 60% for the artificial neural network trained with BP and 76.39% for the artificial neural network trained with ABC. Training and test phases were repeated 30 times to obtain these average performance measurements. This level of performance shows that the artificial neural network trained with ABC is successful in classifying aroma data.

  12. Interaction of BDE-47 and its Hydroxylated Metabolite 6-OH-BDE-47 with the Human ABC Efflux Transporters P-gp and BCRP: Considerations for Human Exposure and Risk Assessment

    Science.gov (United States)

    ATP binding cassette (ABC) transporters, including P-glycoprotein (P-gp; also known as MDR1, ABCB1) and breast cancer resistance protein (BCRP; also known as ABCG2), are membrane-bound proteins that mediate the cellular efflux of xenobiotics as an important defense against chemic...

  13. Reduction of U(VI) by the deep subsurface bacterium, Thermus scotoductus SA-01, and the involvement of the ABC transporter protein.

    Science.gov (United States)

    Cason, Errol Duncan; Piater, Lizelle Ann; van Heerden, Esta

    2012-02-01

    In this study we investigated the effect of uranium on the growth of the bacterium Thermus scotoductus strain SA-01 as well as the whole cell U(VI) reduction capabilities of the organism. Also, site-directed mutagenesis confirmed the identity of a protein capable of a possible alternative mechanism of U(VI) reduction. SA-01 can grow aerobically in up to 1.25 mM uranium and has the capability to reduce low levels of U(VI) in under 20 h. TEM analysis performed on cells exposed to uranium showed extracellular and membrane-bound accumulation of uranium. The reductase-like protein was surprisingly identified as a peptide ABC transporter, peptide-binding protein. This study showcases the concept of protein promiscuity, where this protein with a distinct function in situ can also have the unintended function of a reactant for the reduction of U(VI). Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation

    Science.gov (United States)

    2012-01-01

    Background The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC) Superfamily and Major Facilitator Superfamily (MFS) in S. cerevisiae were scrutinized for a role in ethanol stress resistance. Results A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased 3 H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. Conclusions PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to improve alcoholic

  15. Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation.

    Science.gov (United States)

    Teixeira, Miguel C; Godinho, Cláudia P; Cabrito, Tânia R; Mira, Nuno P; Sá-Correia, Isabel

    2012-07-27

    The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC) Superfamily and Major Facilitator Superfamily (MFS) in S. cerevisiae were scrutinized for a role in ethanol stress resistance. A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased ³H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to improve alcoholic fermentation performance for sustainable bio

  16. Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation

    Directory of Open Access Journals (Sweden)

    Teixeira Miguel C

    2012-07-01

    Full Text Available Abstract Background The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC Superfamily and Major Facilitator Superfamily (MFS in S. cerevisiae were scrutinized for a role in ethanol stress resistance. Results A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased 3 H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. Conclusions PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to

  17. Effects of deletion of the Streptococcus pneumoniae lipoprotein diacylglyceryl transferase gene lgt on ABC transporter function and on growth in vivo.

    Directory of Open Access Journals (Sweden)

    Suneeta Chimalapati

    Full Text Available Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt, deletion of the corresponding gene potentially allows the characterisation of the overall importance of lipoproteins for specific bacterial functions. We have used a Δlgt mutant strain of Streptococcus pneumoniae to investigate the effects of loss of lipoprotein attachment on cation acquisition, growth in media containing specific carbon sources, and virulence in different infection models. Immunoblots of triton X-114 extracts, flow cytometry and immuno-fluorescence microscopy confirmed the Δlgt mutant had markedly reduced lipoprotein expression on the cell surface. The Δlgt mutant had reduced growth in cation depleted medium, increased sensitivity to oxidative stress, reduced zinc uptake, and reduced intracellular levels of several cations. Doubling time of the Δlgt mutant was also increased slightly when grown in medium with glucose, raffinose and maltotriose as sole carbon sources. These multiple defects in cation and sugar ABC transporter function for the Δlgt mutant were associated with only slightly delayed growth in complete medium. However the Δlgt mutant had significantly reduced growth in blood or bronchoalveolar lavage fluid and a marked impairment in virulence in mouse models of nasopharyngeal colonisation, sepsis and pneumonia. These data suggest that for S. pneumoniae loss of surface localisation of lipoproteins has widespread effects on ABC transporter functions that collectively prevent the Δlgt mutant from establishing invasive infection.

  18. Human ATP-binding cassette transporter 1 (ABC1): Genomic organization and identification of the genetic defect in the original Tangier disease kindred

    Science.gov (United States)

    Remaley, Alan T.; Rust, Stephan; Rosier, Marie; Knapper, Cathy; Naudin, Laurent; Broccardo, Cyril; Peterson, Katherine M.; Koch, Christine; Arnould, Isabelle; Prades, Catherine; Duverger, Nicholas; Funke, Harald; Assman, Gerd; Dinger, Maria; Dean, Michael; Chimini, Giovanna; Santamarina-Fojo, Silvia; Fredrickson, Donald S.; Denefle, Patrice; Brewer, H. Bryan

    1999-01-01

    Tangier disease is characterized by low serum high density lipoproteins and a biochemical defect in the cellular efflux of lipids to high density lipoproteins. ABC1, a member of the ATP-binding cassette family, recently has been identified as the defective gene in Tangier disease. We report here the organization of the human ABC1 gene and the identification of a mutation in the ABC1 gene from the original Tangier disease kindred. The organization of the human ABC1 gene is similar to that of the mouse ABC1 gene and other related ABC genes. The ABC1 gene contains 49 exons that range in size from 33 to 249 bp and is over 70 kb in length. Sequence analysis of the ABC1 gene revealed that the proband for Tangier disease was homozygous for a deletion of nucleotides 3283 and 3284 (TC) in exon 22. The deletion results in a frameshift mutation and a premature stop codon starting at nucleotide 3375. The product is predicted to encode a nonfunctional protein of 1,084 aa, which is approximately half the size of the full-length ABC1 protein. The loss of a Mnl1 restriction site, which results from the deletion, was used to establish the genotype of the rest of the kindred. In summary, we report on the genomic organization of the human ABC1 gene and identify a frameshift mutation in the ABC1 gene of the index case of Tangier disease. These results will be useful in the future characterization of the structure and function of the ABC1 gene and the analysis of additional ABC1 mutations in patients with Tangier disease. PMID:10535983

  19. Type III apical transportation of root canal

    Directory of Open Access Journals (Sweden)

    Shiv P Mantri

    2012-01-01

    Full Text Available Procedural accidents leading to complications such as canal transportation have been ascribed to inapt cleaning and shaping concepts. Canal transportation is an undesirable deviation from the natural canal path. Herewith a case of apical transportation of root canal resulting in endodontic retreatment failure and its management is presented. A healthy 21-year-old young male presented discomfort and swelling associated with painful endodontically retreated maxillary incisor. Radiograph revealed periradicular radiolucency involving underfilled 11 and overfilled 12. Insufficiently obturated 11 exhibited apical transportation of canal. This type III transportation was treated by periradicular surgery and repair using white mineral trioxide aggregate (MTA. Comfortable asymptomatic patient presented uneventful healing at third and fourth month recall visits. A decrease in the size of radiolucency in radiograph supported the clinical finding. In the present case, MTA is useful in repairing the transportation defect. The result of these procedures is predictable and successful.

  20. Effects of in vitro exposure to ivermectin and levamisole on the expression patterns of ABC transporters in Haemonchus contortus larvae

    Directory of Open Access Journals (Sweden)

    Ali Raza

    2016-08-01

    Full Text Available This study investigated the interaction of ATP binding cassette (ABC transport proteins with ivermectin (IVM and levamisole (LEV in larvae of susceptible and resistant isolates of Haemonchus contortus in vitro by measuring transcription patterns following exposure to these anthelmintics. Furthermore, we studied the consequences of drug exposure by measuring the sensitivity of L3 to subsequent exposure to higher drug concentrations using larval migration assays. The most highly transcribed transporter genes in both susceptible and resistant L3 were pgp-9.3, abcf-1, mrp-5, abcf-2, pgp-3, and pgp-10. The resistant isolate showed significantly higher transcription of pgp-1, pgp-9.1 and pgp-9.2 compared to the susceptible isolate. Five P-gp genes and the haf-6 gene showed significantly higher transcription (up to 12.6-fold after 3 h exposure to IVM in the resistant isolate. Similarly, five P-gp genes, haf-6 and abcf-1 were transcribed at significantly higher levels (up to 10.3-fold following 3 h exposure to LEV in this isolate. On the other hand, there were no significant changes in transcriptional patterns of all transporter genes in the susceptible isolate following 3 and 6 h exposure to IVM or LEV. In contrast to these isolate-specific transcription changes, both isolates showed an increase in R-123 efflux following exposure to the drugs, suggesting that the drugs stimulated activity of existing transporter proteins in both isolates. Exposure of resistant larvae to IVM or LEV resulted, in some instances, in an increase in the proportion of the population able to migrate at the highest IVM concentrations in subsequent migration assays. The significant increase in transcription of some ABC transporter genes following 3 h exposure to both IVM and LEV in the resistant isolate only, suggests that an ability to rapidly upregulate protective pathways in response to drugs may be a component of the resistance displayed by this isolate.

  1. ABC Technology Development Program

    International Nuclear Information System (INIS)

    1994-01-01

    The Accelerator-Based Conversion (ABC) facility will be designed to accomplish the following mission: 'Provide a weapon's grade plutonium disposition capability in a safe, economical, and environmentally sound manner on a prudent schedule for [50] tons of weapon's grade plutonium to be disposed on in [20] years.' This mission is supported by four major objectives: provide a reliable plutonium disposition capability within the next [15] years; provide a level of safety and of safety assurance that meets or exceeds that afforded to the public by modern commercial nuclear power plants; meet or exceed all applicable federal, state, and local regulations or standards for environmental compliance; manage the program in a cost effective manner. The ABC Technology Development Program defines the technology development activities that are required to accomplish this mission. The technology development tasks are related to the following topics: blanket system; vessel systems; reactivity control systems; heat transport system components; energy conversion systems; shutdown heat transport systems components; auxiliary systems; technology demonstrations - large scale experiments

  2. RNA-seq analysis of the effect of kanamycin and the ABC transporter AtWBC19 on Arabidopsis thaliana seedlings reveals changes in metal content.

    Directory of Open Access Journals (Sweden)

    Ayalew Mentewab

    Full Text Available Plants are exposed to antibiotics produced by soil microorganisms, but little is known about their responses at the transcriptional level. Likewise, few endogenous mechanisms of antibiotic resistance have been reported. The Arabidopsis thaliana ATP Binding Cassette (ABC transporter AtWBC19 (ABCG19 is known to confer kanamycin resistance, but the exact mechanism of resistance is not well understood. Here we examined the transcriptomes of control seedlings and wbc19 mutant seedlings using RNA-seq analysis. Exposure to kanamycin indicated changes in the organization of the photosynthetic apparatus, metabolic fluxes and metal uptake. Elemental analysis showed a 60% and 80% reduction of iron uptake in control and wbc19 mutant seedlings respectively, upon exposure to kanamycin. The drop in iron content was accompanied by the upregulation of the gene encoding for FERRIC REDUCTION OXIDASE 6 (FRO6 in mutant seedlings but not by the differential expression of other transport genes known to be induced by iron deficiency. In addition, wbc19 mutants displayed a distinct expression profile in the absence of kanamycin. Most notably the expression of several zinc ion binding proteins, including ZINC TRANSPORTER 1 PRECURSOR (ZIP1 was increased, suggesting abnormal zinc uptake. Elemental analysis confirmed a 50% decrease of zinc content in wbc19 mutants. Thus, the antibiotic resistance gene WBC19 appears to also have a role in zinc uptake.

  3. Yeast ABC proteins involved in multidrug resistance.

    Science.gov (United States)

    Piecuch, Agata; Obłąk, Ewa

    2014-03-01

    Pleiotropic drug resistance is a complex phenomenon that involves many proteins that together create a network. One of the common mechanisms of multidrug resistance in eukaryotic cells is the active efflux of a broad range of xenobiotics through ATP-binding cassette (ABC) transporters. Saccharomyces cerevisiae is often used as a model to study such activity because of the functional and structural similarities of its ABC transporters to mammalian ones. Numerous ABC transporters are found in humans and some are associated with the resistance of tumors to chemotherapeutics. Efflux pump modulators that change the activity of ABC proteins are the most promising candidate drugs to overcome such resistance. These modulators can be chemically synthesized or isolated from natural sources (e.g., plant alkaloids) and might also be used in the treatment of fungal infections. There are several generations of synthetic modulators that differ in specificity, toxicity and effectiveness, and are often used for other clinical effects.

  4. 75 FR 49549 - ABC & D Recycling, Inc.-Lease and Operation Exemption-a Line of Railroad in Ware, MA

    Science.gov (United States)

    2010-08-13

    ... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35397] ABC & D Recycling, Inc.--Lease and Operation Exemption--a Line of Railroad in Ware, MA ABC & D Recycling, Inc. (ABC & D...\\ The line is currently operated by the Massachusetts Central Railroad Corporation.\\2\\ \\1\\ ABC & D...

  5. Preliminary time-of-flight neutron diffraction studies of Escherichia coli ABC transport receptor phosphate-binding protein at the Protein Crystallography Station.

    Science.gov (United States)

    Sippel, K H; Bacik, J; Quiocho, F A; Fisher, S Z

    2014-06-01

    Inorganic phosphate is an essential molecule for all known life. Organisms have developed many mechanisms to ensure an adequate supply, even in low-phosphate conditions. In prokaryotes phosphate transport is instigated by the phosphate-binding protein (PBP), the initial receptor for the ATP-binding cassette (ABC) phosphate transporter. In the crystal structure of the PBP-phosphate complex, the phosphate is completely desolvated and sequestered in a deep cleft and is bound by 13 hydrogen bonds: 12 to protein NH and OH donor groups and one to a carboxylate acceptor group. The carboxylate plays a key recognition role by accepting a phosphate hydrogen. PBP phosphate affinity is relatively consistent across a broad pH range, indicating the capacity to bind monobasic (H2PO4-) and dibasic (HPO4(2-)) phosphate; however, the mechanism by which it might accommodate the second hydrogen of monobasic phosphate is unclear. To answer this question, neutron diffraction studies were initiated. Large single crystals with a volume of 8 mm3 were grown and subjected to hydrogen/deuterium exchange. A 2.5 Å resolution data set was collected on the Protein Crystallography Station at the Los Alamos Neutron Science Center. Initial refinement of the neutron data shows significant nuclear density, and refinement is ongoing. This is the first report of a neutron study from this superfamily.

  6. In vitro characterization of ABC transporters involved in the absorption and distribution of liensinine and its analogs.

    Science.gov (United States)

    Yu, Lushan; Shen, Qi; Zhou, Quan; Jiang, Huidi; Bi, Huichang; Huang, Min; Zhou, Hui; Zeng, Su

    2013-11-25

    Lotus plumule, the dried young cotyledon and radicle of the Nelumbo nucifera Gaertn. (Fam. Nymphaeaceae) ripe seed, is a famous Traditional Chinese Medicine to remove heat from the heart, anchor the mind, improve seminal emission, and arrest bleeding for centuries in China. Liensinine and its analogs neferine and isoliensinine are the major active components in lotus plumule. Aim of the study is to investigate the association of liensinine, neferine, and isoliensinine with efflux transporters. Caco-2, MDCK, MDCK-MDR1, and MDCK-MRP2 were used as cell models for the transcellular transport and accumulation studies. The results obtained in Caco-2 cells suggested that P-glycoprotein (P-gp) might be involved in transcellular transport. Cellular accumulation and transport experiments were further performed in MDCK-MDR1 cells. GF120918 and cyclosporine A were found to completely inhibit the efflux, and the net efflux ratios of these alkaloids exhibited saturation over the concentration range. No significant differences in liensinine accumulation and transport were observed between MDCK and MDCK-MRP2 cells. These results demonstrated that liensinine, neferine, and isoliensinine are substrates of P-gp, whereas MRP2 is not involved in the transport process, suggesting that P-gp might be responsible for the absorption and distribution of the 3 alkaloids. © 2013 Elsevier Ireland Ltd. All rights reserved.

  7. Diet Treatment Glucose Transporter Type 1 Deficiency (G1D)

    Science.gov (United States)

    2017-10-17

    GLUT1DS1; Epilepsy; Glut1 Deficiency Syndrome 1, Autosomal Recessive; Glucose Metabolism Disorders; Glucose Transport Defect; Glucose Transporter Type 1 Deficiency Syndrome; Glucose Transporter Protein Type 1 Deficiency Syndrome

  8. The Absence of the Transcription Factor Yrr1p, Identified from Comparative Genome Profiling, Increased Vanillin Tolerance Due to Enhancements of ABC Transporters Expressing, rRNA Processing and Ribosome Biogenesis in Saccharomyces cerevisiae.

    Science.gov (United States)

    Wang, Xinning; Liang, Zhenzhen; Hou, Jin; Shen, Yu; Bao, Xiaoming

    2017-01-01

    Enhancing the tolerance of Saccharomyces cerevisiae to inhibitors derived from lignocellulose is conducive to producing biofuel and chemicals using abundant lignocellulosic materials. Vanillin is a major type of phenolic inhibitor in lignocellulose hydrolysates for S. cerevisiae . In the present work, the factors beneficial to vanillin resistance in yeast were identified from the vanillin-resistant strain EMV-8, which was derived from strain NAN-27 by adaptive evolution. We found 450 SNPs and 44 genes with InDels in the vanillin-tolerant strain EMV-8 by comparing the genome sequences of EMV-8 and NAN-27. To investigate the effects of InDels, InDels were deleted in BY4741, respectively. We demonstrated that the deletion of YRR1 improved vanillin tolerance of strain. In the presence of 6 mM vanillin, deleting YRR1 increase the maximum specific growth rate and the vanillin consumption rate by 142 and 51%, respectively. The subsequent transcriptome analysis revealed that deleting YRR1 resulted in changed expression of over 200 genes in the presence of 5 mM vanillin. The most marked changes were the significant up-regulation of the dehydrogenase ADH7 , several ATP-binding cassette (ABC) transporters, and dozens of genes involved in ribosome biogenesis and rRNA processing. Coincidently, the crude enzyme solution of BY4741( yrr1 Δ) exhibited higher NADPH-dependent vanillin reduction activity than control. In addition, overexpressing the ABC transporter genes PDR5, YOR1 , and SNQ2 , as well as the RNA helicase gene DBP2 , increased the vanillin tolerance of strain. Interestingly, unlike the marked changes we mentioned above, under vanillin-free conditions, there are only limited transcriptional differences between wildtype and yrr1 Δ. This indicated that vanillin might act as an effector in Yrr1p-related regulatory processes. The new findings of the relationship between YRR1 and vanillin tolerance, as well as the contribution of rRNA processing and ribosome biogenesis to

  9. ABC Kinga kauplused = ABC King shoe stores

    Index Scriptorium Estoniae

    2011-01-01

    Tallinnas Kristiine keskuses, Tartu Kaubamajas ja Pärnus Port Artur 2 asuvate ABC Kinga kaupluste sisekujundusest. Sisearhitekid Andres Labi ja Janno Roos (Ruumilabor OÜ), loetletud nende ühiselt tehtud töid

  10. Characterization of a lactose-responsive promoter of ATP-binding cassette (ABC) transporter gene from Lactobacillus acidophilus 05-172.

    Science.gov (United States)

    Zeng, Zhu; Zuo, Fanglei; Yu, Rui; Zhang, Bo; Ma, Huiqin; Chen, Shangwu

    2017-09-01

    A novel lactose-responsive promoter of the ATP-binding cassette (ABC) transporter gene Lba1680 of Lactobacillus acidophilus strain 05-172 isolated from a traditionally fermented dairy product koumiss was characterized. In L. acidophilus 05-172, expression of Lba1680 was induced by lactose, with lactose-induced transcription of Lba1680 being 6.1-fold higher than that induced by glucose. This is in contrast to L. acidophilus NCFM, a strain isolated from human feces, in which expression of Lba1680 and Lba1679 is induced by glucose. Both gene expression and enzyme activity assays in L. paracasei transformed with a vector containing the inducible Lba1680 promoter (PLba1680) of strain 05-172 and a heme-dependent catalase gene as reporter confirmed that PLba1680 is specifically induced by lactose. Its regulatory expression could not be repressed by glucose, and was independent of cAMP receptor protein. This lactose-responsive promoter might be used in the expression of functional genes in L. paracasei incorporated into a lactose-rich environment, such as dairy products. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. The ABC model of recombination reinterpreted: Impact on understanding carrier transport and efficiency droop in InGaN/GaN light emitting diodes

    Science.gov (United States)

    Hopkins, M. A.; Allsopp, D. W. E.; Kappers, M. J.; Oliver, R. A.; Humphreys, C. J.

    2017-12-01

    The efficiency of light emitting diodes (LEDs) remains a topic of great contemporary interest due to their potential to reduce the amount of energy consumed in lighting. The current consensus is that electrons and holes distribute themselves through the emissive region by a drift-diffusion process which results in a highly non-uniform distribution of the light emission and can reduce efficiency. In this paper, the measured variations in the external quantum efficiency of a range of InGaN/GaN LEDs with different numbers of quantum wells (QWs) are shown to compare closely with the predictions of a revised ABC model, in which it is assumed that the electrically injected electrons and holes are uniformly distributed through the multi-quantum well (MQW) region, or nearly so, and hence carrier recombination occurs equally in all the quantum wells. The implications of the reported results are that drift-diffusion plays a far lesser role in cross-well carrier transport than previously thought; that the dominant cause of efficiency droop is intrinsic to the quantum wells and that reductions in the density of non-radiative recombination centers in the MQW would enable the use of more QWs and thereby reduce Auger losses by spreading carriers more evenly across a wider emissive region.

  12. ABC transporter PEN3/PDR8/ABCG36 interacts with calmodulin that, like PEN3, is required for Arabidopsis nonhost resistance.

    Science.gov (United States)

    Campe, Ruth; Langenbach, Caspar; Leissing, Franz; Popescu, George V; Popescu, Sorina C; Goellner, Katharina; Beckers, Gerold J M; Conrath, Uwe

    2016-01-01

    Nonhost resistance (NHR) is the most prevalent form of plant immunity. In Arabidopsis, NHR requires membrane-localized ATP-binding cassette (ABC) transporter PENETRATION (PEN) 3. Upon perception of pathogen-associated molecular patterns, PEN3 becomes phosphorylated, suggestive of PEN3 regulation by post-translational modification. Here, we investigated the PEN3 protein interaction network. We probed the Arabidopsis protein microarray AtPMA-5000 with the N-terminal cytoplasmic domain of PEN3. Several of the proteins identified to interact with PEN3 in vitro represent cellular Ca(2+) sensors, including calmodulin (CaM) 3, CaM7 and several CaM-like proteins, pointing to the importance of Ca(2+) sensing to PEN3-mediated NHR. We demonstrated co-localization of PEN3 and CaM7, and we confirmed PEN3-CaM interaction in vitro and in vivo by PEN3 pull-down with CaM Sepharose, CaM overlay assay and bimolecular fluorescence complementation. We also show that just like in pen3, NHR to the nonadapted fungal pathogens Phakopsora pachyrhizi and Blumeria graminis f.sp. hordei is compromised in the Arabidopsis cam7 and pen3 cam7 mutants. Our study discloses CaM7 as a PEN3-interacting protein crucial to Arabidopsis NHR and emphasizes the importance of Ca(2+) sensing to plant immunity. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  13. The function of the ATP-binding cassette (ABC) transporter ABCB1 is not susceptible to actin disruption

    NARCIS (Netherlands)

    Meszaros, Peter; Hummel, Ina; Klappe, Karin; Draghiciu, Oana; Hoekstra, Dick; Kok, Jan W.

    Previously we have shown that the activity of the multidrug transporter ABCC1 (multidrug resistance protein 1), and its localization in lipid rafts, depends on cortical actin (Hummel I, Klappe K, Ercan C, Kok JW. Mol. Pharm. 2011 79, 229-40). Here we show that the efflux activity of the ATP-binding

  14. Relative rates of amino acid import via the ABC transporter GlnPQ determine the growth performance of Lactococcus lactis

    NARCIS (Netherlands)

    Fulyani, Faizah; Schuurman-Wolters, Geesina; Slotboom, Dirk-Jan; Poolman, Bert

    The GlnPQ transporter from Lactococcus lactis has the remarkable feature of having two substrate-binding domains (SBD) fused to the N-terminus of the transmembrane domain (TMD), and thus four SBDs are present in the homodimeric complex. Although X-ray structures and ligand binding data are available

  15. The role of peroxisomal ABC transporters in the mouse adrenal gland: the loss of Abcd2 (ALDR), Not Abcd1 (ALD), causes oxidative damage.

    Science.gov (United States)

    Lu, Jyh-Feng; Barron-Casella, Emily; Deering, Rebecca; Heinzer, Ann K; Moser, Ann B; deMesy Bentley, Karen L; Wand, Gary S; C McGuinness, Martina; Pei, Zhengtong; Watkins, Paul A; Pujol, Aurora; Smith, Kirby D; Powers, James M

    2007-03-01

    X-linked adreno-leukodystrophy is a progressive, systemic peroxisomal disorder that primarily affects the adrenal cortex, as well as myelin and axons of the central nervous system. Marked phenotypic heterogeneity does not correlate with disease-causing mutations in ABCD1, which encodes a peroxisomal membrane protein that is a member of the ABC transmembrane transporter proteins. The precise physiological functions of ABCD1 and ABCD2, a closely related peroxisomal membrane half-transporter, are unknown. The abcd1 knockout mouse does not develop the inflammatory demyelination so typical and devastating in adreno-leukodystrophy, but it does display the same lamellae and lipid profiles in adrenocortical cells under the electron microscope as the human patients. The adrenocortical cells in the mouse also exhibit immunohistochemical evidence of oxidative stress at 12 weeks but no evidence of oxidative damage. To better understand the pathogenesis of this complex disease, we evaluate the adrenal lesion of the abcd1 knockout mouse as a function of normal aging, dietary or therapeutic manipulations, and abcd genotype. The loss of abcd2 causes oxidative stress in the adrenal at 12 weeks, as judged by increased immunoreactivity for the mitochondrial manganese superoxide dismutase, in both the inner cortex and medulla. The loss of abcd2 (n=20), but not abcd1 (n=27), results in the spontaneous and premature deposition of ceroid, a known end-product of oxidative damage, predominantly in adrenal medullary cells. These data indicate that the loss of abcd2 results in greater oxidative stress in murine adrenal cells than the loss of abcd1, providing a clue to its cellular function. We also find that the adrenocortical lesion of the abcd1 knockout mouse does not produce functional impairment at ten to nineteen months or overt hypocortisolism at any age, nor does it progress histologically; these and other data align this mouse model closer to human female heterozygotes than to male

  16. Enhancing the ABC Cross

    OpenAIRE

    Euske, K.J.; Vercio, Alan

    2007-01-01

    The purpose of the ABC Cross was to portray both a cost and process view of an organization as simply as possible. Unfortunately, the model’s simplified form does not capture the real value of activity-based costing (ABC) for cost accounting that emerged in the mid-1980s. Here we present several ABC models that can help functional and process managers make better decisions.

  17. Multidrug resistance mediated by ABC transporters in osteosarcoma cell lines: mRNA analysis and functional radiotracer studies

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Celia Maria Freitas [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal)]. E-mail: cgomes@ibili.uc.pt; van Paassen, Heidi [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Romeo, Salvatore [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Welling, Mick M. [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Feitsma, R.I.J. [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Abrunhosa, Antero J. [Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal); Botelho, M. Filomena [Faculty of Medicine, Institute of Biophysics/Biomathematics, IBILI, 3000-354 Coimbra (Portugal); Hogendoorn, Pancras C.W. [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Pauwels, Ernest [Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, 2300 RC Leiden (Netherlands); Cleton-Jansen, Anne Marie [Department of Pathology, Leiden University Medical Center, 2300 RC Leiden (Netherlands)

    2006-10-15

    Drug resistance remains a significant impediment to successful chemotherapy and constitutes a major prognostic factor in osteosarcoma (OS) patients. This study was designed to identify the role and prognostic significance of multidrug-resistance (MDR)-related transporters, such as multidrug resistance protein 1 (MDR1), multidrug-resistance-associated protein (MRP1) and breast-cancer-related protein (BCRP), in OS using cationic lipophilic radiotracers. We evaluated the chemosensitivity of four OS cell lines (Saos-2, 143B, MNNG/HOS and U-2OS) to doxorubicin (DOX), cisplatin (CIS) and methotrexate. The expression of MDR-related transporters was analyzed at mRNA level by quantitative polymerase chain reaction and at functional level by {sup 99m}Tc sestamibi and {sup 99m}Tc tetrofosmin. The effectiveness of MDR modulators [cyclosporin A (CsA) and imatinib] on transporter inhibition and on the reversal of resistance was also assessed. MNNG/HOS and U-2OS cells expressing high levels of MDR1 were highly resistant to DOX and showed reduced accumulation and higher efflux for radiotracers. Although MRP1 was uniformly expressed in all cells, only U-2OS was resistant to CIS. CsA restored sensitivity to DOX and CIS, and enhanced the accumulation and efflux half-life of radiotracers in MDR1-expressing cell lines. The chemosensitivity of OS cells to DOX was strongly dependent on mRNA MDR1 expression and could be circumvented by adding CsA. The kinetic parameters of radiotracers correlated with MDR1 expression levels, hence predicting DOX resistance. We concluded that sensitivity to chemotherapy is strongly dependent on the expression of MDR1 transporter and that radiotracer studies could prove clinically useful in predicting chemotherapy response and in evaluating the efficacy of MDR-reversing agents.

  18. An ABC transporter B family protein, ABCB19, is required for cytoplasmic streaming and gravitropism of the inflorescence stems.

    Science.gov (United States)

    Okamoto, Keishi; Ueda, Haruko; Shimada, Tomoo; Tamura, Kentaro; Koumoto, Yasuko; Tasaka, Masao; Morita, Miyo Terao; Hara-Nishimura, Ikuko

    2016-01-01

    A significant feature of plant cells is the extensive motility of organelles and the cytosol, which was originally defined as cytoplasmic streaming. We suggested previously that a three-way interaction between plant-specific motor proteins myosin XIs, actin filaments, and the endoplasmic reticulum (ER) was responsible for cytoplasmic streaming. (1) Currently, however, there are no reports of molecular components for cytoplasmic streaming other than the actin-myosin-cytoskeleton and ER-related proteins. In the present study, we found that elongated cells of inflorescence stems of Arabidopsis thaliana exhibit vigorous cytoplasmic streaming. Statistical analysis showed that the maximal velocity of plastid movements is 7.26 µm/s, which is much faster than the previously reported velocities of organelles. Surprisingly, the maximal velocity of streaming in the inflorescence stem cells was significantly reduced to 1.11 µm/s in an Arabidopsis mutant, abcb19-101, which lacks ATP BINDING CASSETTE SUBFAMILY B19 (ABCB19) that mediates the polar transport of the phytohormone auxin together with PIN-FORMED (PIN) proteins. Polar auxin transport establishes the auxin concentration gradient essential for plant development and tropisms. Deficiency of ABCB19 activity eventually caused enhanced gravitropic responses of the inflorescence stems and abnormally flexed inflorescence stems. These results suggest that ABCB19-mediated auxin transport plays a role not only in tropism regulation, but also in cytoplasmic streaming.

  19. Loss of AtPDR11, a plasma membrane-localized ABC transporter, confers paraquat tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Xi, Jing; Xu, Ping; Xiang, Cheng-Bin

    2012-03-01

    Paraquat is one of the most widely used herbicides in the world. However, no paraquat transporter has been isolated in plants. Here, we describe paraquat-tolerant mutant pqt24-1, isolated from an activation-tagging library on the basis of its tolerance to 2 μm paraquat in the seedling stage. Molecular analysis revealed that the T-DNA was inserted in the 13th exon of At1g66950, which encodes AtPDR11, a member of the ATP-binding cassette transporter superfamily. As a result, AtPDR11 was knocked out in the mutant. Loss-of-function mutations of AtPDR11 led to reduced paraquat accumulation in plant cells. In addition, the AtPDR11 protein was specifically localized in the plasmalemma, suggesting AtPDR11 as a potential transporter of paraquat. This conclusion was supported by kinetic analysis of paraquat import. Further studies showed that the transcript level of AtPDR11 could be strongly induced by paraquat and other abiotic stresses including H(2) O(2) , indicating possible up-regulation of AtPDR11 expression by oxidative stress signaling. Thus, our data suggest that paraquat is an opportunistic substrate of AtPDR11 and the enhanced paraquat tolerance of pqt24-1 is due to reduced uptake of paraquat into plant cells. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  20. An ABC transporter B family protein, ABCB19, is required for cytoplasmic streaming and gravitropism of the inflorescence stems

    Science.gov (United States)

    Okamoto, Keishi; Ueda, Haruko; Shimada, Tomoo; Tamura, Kentaro; Koumoto, Yasuko; Tasaka, Masao; Morita, Miyo Terao; Hara-Nishimura, Ikuko

    2016-01-01

    Abstract A significant feature of plant cells is the extensive motility of organelles and the cytosol, which was originally defined as cytoplasmic streaming. We suggested previously that a three-way interaction between plant-specific motor proteins myosin XIs, actin filaments, and the endoplasmic reticulum (ER) was responsible for cytoplasmic streaming.1 Currently, however, there are no reports of molecular components for cytoplasmic streaming other than the actin-myosin-cytoskeleton and ER-related proteins. In the present study, we found that elongated cells of inflorescence stems of Arabidopsis thaliana exhibit vigorous cytoplasmic streaming. Statistical analysis showed that the maximal velocity of plastid movements is 7.26 µm/s, which is much faster than the previously reported velocities of organelles. Surprisingly, the maximal velocity of streaming in the inflorescence stem cells was significantly reduced to 1.11 µm/s in an Arabidopsis mutant, abcb19-101, which lacks ATP BINDING CASSETTE SUBFAMILY B19 (ABCB19) that mediates the polar transport of the phytohormone auxin together with PIN-FORMED (PIN) proteins. Polar auxin transport establishes the auxin concentration gradient essential for plant development and tropisms. Deficiency of ABCB19 activity eventually caused enhanced gravitropic responses of the inflorescence stems and abnormally flexed inflorescence stems. These results suggest that ABCB19-mediated auxin transport plays a role not only in tropism regulation, but also in cytoplasmic streaming. PMID:26337543

  1. Probing gas and dust in the tidal tail of NGC 5221 with the type Ia supernova iPTF16abc

    Science.gov (United States)

    Ferretti, R.; Amanullah, R.; Goobar, A.; Petrushevska, T.; Borthakur, S.; Bulla, M.; Fox, O.; Freeland, E.; Fremling, C.; Hangard, L.; Hayes, M.

    2017-10-01

    Context. Type Ia supernovae (SNe Ia) can be used to address numerous questions in astrophysics and cosmology. Due to their well known spectral and photometric properties, SNe Ia are well suited to study gas and dust along the lines-of-sight to the explosions. For example, narrow Na I D and Ca II H&K absorption lines can be studied easily, because of the well-defined spectral continuum of SNe Ia around these features. Aims: We aim to study the gas and dust along the line-of-sight to iPTF16abc, which occurred in an unusual location, in a tidal arm, 80 kpc from centre of the galaxy NGC 5221. Methods: Using a time-series of high-resolution spectra, we have examined narrow Na I D and Ca II H&K absorption features for variations in time, which would be indicative for circumstellar (CS) matter. Furthermore, we have taken advantage of the well known photometric properties of SNe Ia to determine reddening due to dust along the line-of-sight. Results: From the lack of variations in Na I D and Ca II H&K, we determine that none of the detected absorption features originate from the CS medium of iPTF16abc. While the Na I D and Ca II H&K absorption is found to be optically thick, a negligible amount of reddening points to a small column of interstellar dust. Conclusions: We find that the gas along the line-of-sight to iPTF16abc is typical of what might be found in the interstellar medium (ISM) within a galaxy. It suggests that we are observing gas that has been tidally stripped during an interaction of NGC 5221 with one of its neighbouring galaxies in the past 109 yr. In the future, the gas clouds could become the locations of star formation. On a longer time scale, the clouds might diffuse, enriching the circum-galactic medium (CGM) with metals. The gas profile along the line-of-sight should be useful for future studies of the dynamics of the galaxy group containing NGC 5221. Based on observations collected at the European Organisation for Astronomical Research in the Southern

  2. PPAR Medicines and Human Disease: The ABCs of It All

    Directory of Open Access Journals (Sweden)

    Anthony J. Apostoli

    2012-01-01

    Full Text Available ATP-dependent binding cassette (ABC transporters are a family of transmembrane proteins that pump a variety of hydrophobic compounds across cellular and subcellular barriers and are implicated in human diseases such as cancer and atherosclerosis. Inhibition of ABC transporter activity showed promise in early preclinical studies; however, the outcomes in clinical trials with these agents have not been as encouraging. Peroxisome proliferator-activated receptors (PPARs are ligand-activated transcription factors that regulate genes involved in fat and glucose metabolism, and inflammation. Activation of PPAR signaling is also reported to regulate ABC gene expression. This suggests the potential of PPAR medicines as a novel means of controlling ABC transporter activity at the transcriptional level. This paper summarizes the advances made in understanding how PPAR medicines affect ABC transporters, and the potential implications for impacting on human diseases, in particular with respect to cancer and atherosclerosis.

  3. Genotyping Candida albicans from Candida leukoplakia and non-Candida leukoplakia shows no enrichment of multilocus sequence typing clades but enrichment of ABC genotype C in Candida leukoplakia.

    Directory of Open Access Journals (Sweden)

    Mohammed H Abdulrahim

    Full Text Available Oral leukoplakias are histopathologically-diagnosed as Candida leukoplakia or non-Candida leukoplakia by the presence or absence of hyphae in the superficial epithelium. Candida leukoplakia lesions have significantly increased malignant potential. Candida albicans is the most prevalent fungal species associated with oral leukoplakia and may contribute to malignant transformation of Candida leukoplakia. To date, no detailed population analysis of C. albicans isolates from oral leukoplakia patients has been undertaken. This study investigated whether specific C. albicans genotypes were associated with Candida leukoplakia and non-Candida leukoplakia in a cohort of Irish patients. Patients with histopathologically-defined Candida leukoplakia (n = 31 or non-Candida leukoplakia (n = 47 were screened for Candida species by culture of oral rinse and lesional swab samples. Selected C. albicans isolates from Candida leukoplakia patients (n = 25, non-Candida leukoplakia patients (n = 19 and oral carriage isolates from age and sex matched healthy subjects without leukoplakia (n = 34 were subjected to multilocus sequence typing (MLST and ABC genotyping. MLST revealed that the clade distribution of C. albicans from both Candida leukoplakia and non-Candida leukoplakia lesions overlapped with the corresponding clade distributions of oral carriage isolates and global reference isolates from the MLST database indicating no enrichment of leukoplakia-associated clones. Oral leukoplakia isolates were significantly enriched with ABC genotype C (12/44, 27.3%, particularly Candida leukoplakia isolates (9/25, 36%, relative to oral carriage isolates (3/34, 8.8%. Genotype C oral leukoplakia isolates were distributed in MLST clades 1,3,4,5,8,9 and 15, whereas genotype C oral carriage isolates were distributed in MLST clades 4 and 11.

  4. Genotyping Candida albicans from Candida Leukoplakia and Non-Candida Leukoplakia Shows No Enrichment of Multilocus Sequence Typing Clades but Enrichment of ABC Genotype C in Candida Leukoplakia

    Science.gov (United States)

    Flint, Stephen R.; Coleman, David C.

    2013-01-01

    Oral leukoplakias are histopathologically-diagnosed as Candida leukoplakia or non-Candida leukoplakia by the presence or absence of hyphae in the superficial epithelium. Candida leukoplakia lesions have significantly increased malignant potential. Candida albicans is the most prevalent fungal species associated with oral leukoplakia and may contribute to malignant transformation of Candida leukoplakia. To date, no detailed population analysis of C. albicans isolates from oral leukoplakia patients has been undertaken. This study investigated whether specific C. albicans genotypes were associated with Candida leukoplakia and non-Candida leukoplakia in a cohort of Irish patients. Patients with histopathologically-defined Candida leukoplakia (n = 31) or non-Candida leukoplakia (n = 47) were screened for Candida species by culture of oral rinse and lesional swab samples. Selected C. albicans isolates from Candida leukoplakia patients (n = 25), non-Candida leukoplakia patients (n = 19) and oral carriage isolates from age and sex matched healthy subjects without leukoplakia (n = 34) were subjected to multilocus sequence typing (MLST) and ABC genotyping. MLST revealed that the clade distribution of C. albicans from both Candida leukoplakia and non-Candida leukoplakia lesions overlapped with the corresponding clade distributions of oral carriage isolates and global reference isolates from the MLST database indicating no enrichment of leukoplakia-associated clones. Oral leukoplakia isolates were significantly enriched with ABC genotype C (12/44, 27.3%), particularly Candida leukoplakia isolates (9/25, 36%), relative to oral carriage isolates (3/34, 8.8%). Genotype C oral leukoplakia isolates were distributed in MLST clades 1,3,4,5,8,9 and 15, whereas genotype C oral carriage isolates were distributed in MLST clades 4 and 11. PMID:24058485

  5. A Putative ABC Transporter Permease is Necessary For Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa Under Aerobic, Anaerobic, Planktonic or Biofilm Conditions

    Directory of Open Access Journals (Sweden)

    Cameron eMcDaniel

    2016-04-01

    Full Text Available Pseudomonas aeruginosa (PA is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite (A-NO2-, pH 6.5 at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to A-NO2-. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to A-NO2-, but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin and chloramphenicol, respectively. Treatment of bacteria with A-NO2- plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 25 mM (aerobic, 15 mM (anaerobic A-NO2- and EDTA (1 mM, aerobic, anaerobic, respectively. Most importantly, the PA4455 mutant was also sensitive to A-NO2- in biofilms. A-NO2- sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, A-NO2- as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains.

  6. A Putative ABC Transporter Permease Is Necessary for Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa under Aerobic and Anaerobic Planktonic and Biofilm Conditions.

    Science.gov (United States)

    McDaniel, Cameron; Su, Shengchang; Panmanee, Warunya; Lau, Gee W; Browne, Tristan; Cox, Kevin; Paul, Andrew T; Ko, Seung-Hyun B; Mortensen, Joel E; Lam, Joseph S; Muruve, Daniel A; Hassett, Daniel J

    2016-01-01

    Pseudomonas aeruginosa (PA) is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite ([Formula: see text], pH 6.5) at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to [Formula: see text]. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to [Formula: see text], but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin, and chloramphenicol, respectively. Treatment of bacteria with [Formula: see text] plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 10 mM [Formula: see text], and EDTA (1 mM, aerobic, anaerobic). Most importantly, the PA4455 mutant was also sensitive to [Formula: see text] in biofilms. [Formula: see text] sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM) that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, [Formula: see text] as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains.

  7. ABC transporters and the proteasome complex are implicated in susceptibility to Stevens-Johnson syndrome and toxic epidermal necrolysis across multiple drugs.

    Directory of Open Access Journals (Sweden)

    Paola Nicoletti

    Full Text Available Stevens-Johnson syndrome (SJS and Toxic Epidermal Necrolysis (TEN represent rare but serious adverse drug reactions (ADRs. Both are characterized by distinctive blistering lesions and significant mortality rates. While there is evidence for strong drug-specific genetic predisposition related to HLA alleles, recent genome wide association studies (GWAS on European and Asian populations have failed to identify genetic susceptibility alleles that are common across multiple drugs. We hypothesize that this is a consequence of the low to moderate effect size of individual genetic risk factors. To test this hypothesis we developed Pointer, a new algorithm that assesses the aggregate effect of multiple low risk variants on a pathway using a gene set enrichment approach. A key advantage of our method is the capability to associate SNPs with genes by exploiting physical proximity as well as by using expression quantitative trait loci (eQTLs that capture information about both cis- and trans-acting regulatory effects. We control for known bias-inducing aspects of enrichment based analyses, such as: 1 gene length, 2 gene set size, 3 presence of biologically related genes within the same linkage disequilibrium (LD region, and, 4 genes shared among multiple gene sets. We applied this approach to publicly available SJS/TEN genome-wide genotype data and identified the ABC transporter and Proteasome pathways as potentially implicated in the genetic susceptibility of non-drug-specific SJS/TEN. We demonstrated that the innovative SNP-to-gene mapping phase of the method was essential in detecting the significant enrichment for those pathways. Analysis of an independent gene expression dataset provides supportive functional evidence for the involvement of Proteasome pathways in SJS/TEN cutaneous lesions. These results suggest that Pointer provides a useful framework for the integrative analysis of pharmacogenetic GWAS data, by increasing the power to detect

  8. The ABC and AUSSAT.

    Science.gov (United States)

    McGarritty, Ian

    1985-01-01

    Discusses the Australian Broadcasting Corporation's (ABC) utilization of the AUSSAT telecommunications satellite to extend its television and radio transmission range to reach remote Australian audiences; the satellite's program gathering and interchange capabilities; and ABC's generation of other benefits to offset cost of satellite services.…

  9. Impaired phloem loading in zmsweet13a,b,c sucrose transporter triple knock-out mutants in Zea mays.

    Science.gov (United States)

    Bezrutczyk, Margaret; Hartwig, Thomas; Horschman, Marc; Char, Si Nian; Yang, Jinliang; Yang, Bing; Frommer, Wolf B; Sosso, Davide

    2018-04-01

    Crop yield depends on efficient allocation of sucrose from leaves to seeds. In Arabidopsis, phloem loading is mediated by a combination of SWEET sucrose effluxers and subsequent uptake by SUT1/SUC2 sucrose/H + symporters. ZmSUT1 is essential for carbon allocation in maize, but the relative contribution to apoplasmic phloem loading and retrieval of sucrose leaking from the translocation path is not known. Here we analysed the contribution of SWEETs to phloem loading in maize. We identified three leaf-expressed SWEET sucrose transporters as key components of apoplasmic phloem loading in Zea mays L. ZmSWEET13 paralogues (a, b, c) are among the most highly expressed genes in the leaf vasculature. Genome-edited triple knock-out mutants were severely stunted. Photosynthesis of mutants was impaired and leaves accumulated high levels of soluble sugars and starch. RNA-seq revealed profound transcriptional deregulation of genes associated with photosynthesis and carbohydrate metabolism. Genome-wide association study (GWAS) analyses may indicate that variability in ZmSWEET13s correlates with agronomical traits, especifically flowering time and leaf angle. This work provides support for cooperation of three ZmSWEET13s with ZmSUT1 in phloem loading in Z. mays. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  10. Plant ABC proteins--a unified nomenclature and updated inventory.

    Science.gov (United States)

    Verrier, Paul J; Bird, David; Burla, Bo; Dassa, Elie; Forestier, Cyrille; Geisler, Markus; Klein, Markus; Kolukisaoglu, Uner; Lee, Youngsook; Martinoia, Enrico; Murphy, Angus; Rea, Philip A; Samuels, Lacey; Schulz, Burkhard; Spalding, Edgar J; Yazaki, Kazufumi; Theodoulou, Frederica L

    2008-04-01

    The ABC superfamily comprises both membrane-bound transporters and soluble proteins involved in a broad range of processes, many of which are of considerable agricultural, biotechnological and medical potential. Completion of the Arabidopsis and rice genome sequences has revealed a particularly large and diverse complement of plant ABC proteins in comparison with other organisms. Forward and reverse genetics, together with heterologous expression, have uncovered many novel roles for plant ABC proteins, but this progress has been accompanied by a confusing proliferation of names for plant ABC genes and their products. A consolidated nomenclature will provide much-needed clarity and a framework for future research.

  11. Rhizobium leguminosarum has a second general amino acid permease with unusually broad substrate specificity and high similarity to branched-chain amino acid transporters (Bra/LIV) of the ABC family.

    Science.gov (United States)

    Hosie, A H F; Allaway, D; Galloway, C S; Dunsby, H A; Poole, P S

    2002-08-01

    Amino acid uptake by Rhizobium leguminosarum is dominated by two ABC transporters, the general amino acid permease (Aap) and the branched-chain amino acid permease (Bra(Rl)). Characterization of the solute specificity of Bra(Rl) shows it to be the second general amino acid permease of R. leguminosarum. Although Bra(Rl) has high sequence identity to members of the family of hydrophobic amino acid transporters (HAAT), it transports a broad range of solutes, including acidic and basic polar amino acids (L-glutamate, L-arginine, and L-histidine), in addition to neutral amino acids (L-alanine and L-leucine). While amino and carboxyl groups are required for transport, solutes do not have to be alpha-amino acids. Consistent with this, Bra(Rl) is the first ABC transporter to be shown to transport gamma-aminobutyric acid (GABA). All previously identified bacterial GABA transporters are secondary carriers of the amino acid-polyamine-organocation (APC) superfamily. Also, transport by Bra(Rl) does not appear to be stereospecific as D amino acids cause significant inhibition of uptake of L-glutamate and L-leucine. Unlike all other solutes tested, L-alanine uptake is not dependent on solute binding protein BraC(Rl). Therefore, a second, unidentified solute binding protein may interact with the BraDEFG(Rl) membrane complex during L-alanine uptake. Overall, the data indicate that Bra(Rl) is a general amino acid permease of the HAAT family. Furthermore, Bra(Rl) has the broadest solute specificity of any characterized bacterial amino acid transporter.

  12. The Arabidopsis Peroxisomal ABC Transporter, Comatose, Complements the Saccharomyces cerevisiae pxa1 pxa2Δ Mutant for Metabolism of Long-chain Fatty Acids and Exhibits Fatty Acyl-CoA-stimulated ATPase Activity*

    Science.gov (United States)

    Nyathi, Yvonne; De Marcos Lousa, Carine; van Roermund, Carlo W.; Wanders, Ronald J. A.; Johnson, Barbara; Baldwin, Stephen A.; Theodoulou, Frederica L.; Baker, Alison

    2010-01-01

    The Arabidopsis ABC transporter Comatose (CTS; AtABCD1) is required for uptake into the peroxisome of a wide range of substrates for β-oxidation, but it is uncertain whether CTS itself is the transporter or if the transported substrates are free acids or CoA esters. To establish a system for its biochemical analysis, CTS was expressed in Saccharomyces cerevisiae. The plant protein was correctly targeted to yeast peroxisomes, was assembled into the membrane with its nucleotide binding domains in the cytosol, and exhibited basal ATPase activity that was sensitive to aluminum fluoride and abrogated by mutation of a conserved Walker A motif lysine residue. The yeast pxa1 pxa2Δ mutant lacks the homologous peroxisomal ABC transporter and is unable to grow on oleic acid. Consistent with its exhibiting a function in yeast akin to that in the plant, CTS rescued the oleate growth phenotype of the pxa1 pxa2Δ mutant, and restored β-oxidation of fatty acids with a range of chain lengths and varying degrees of desaturation. When expressed in yeast peroxisomal membranes, the basal ATPase activity of CTS could be stimulated by fatty acyl-CoAs but not by fatty acids. The implications of these findings for the function and substrate specificity of CTS are discussed. PMID:20659892

  13. The Arabidopsis peroxisomal ABC transporter, comatose, complements the Saccharomyces cerevisiae pxa1 pxa2Delta mutant for metabolism of long-chain fatty acids and exhibits fatty acyl-CoA-stimulated ATPase activity.

    Science.gov (United States)

    Nyathi, Yvonne; De Marcos Lousa, Carine; van Roermund, Carlo W; Wanders, Ronald J A; Johnson, Barbara; Baldwin, Stephen A; Theodoulou, Frederica L; Baker, Alison

    2010-09-24

    The Arabidopsis ABC transporter Comatose (CTS; AtABCD1) is required for uptake into the peroxisome of a wide range of substrates for β-oxidation, but it is uncertain whether CTS itself is the transporter or if the transported substrates are free acids or CoA esters. To establish a system for its biochemical analysis, CTS was expressed in Saccharomyces cerevisiae. The plant protein was correctly targeted to yeast peroxisomes, was assembled into the membrane with its nucleotide binding domains in the cytosol, and exhibited basal ATPase activity that was sensitive to aluminum fluoride and abrogated by mutation of a conserved Walker A motif lysine residue. The yeast pxa1 pxa2Δ mutant lacks the homologous peroxisomal ABC transporter and is unable to grow on oleic acid. Consistent with its exhibiting a function in yeast akin to that in the plant, CTS rescued the oleate growth phenotype of the pxa1 pxa2Δ mutant, and restored β-oxidation of fatty acids with a range of chain lengths and varying degrees of desaturation. When expressed in yeast peroxisomal membranes, the basal ATPase activity of CTS could be stimulated by fatty acyl-CoAs but not by fatty acids. The implications of these findings for the function and substrate specificity of CTS are discussed.

  14. Rapportering med ABC modellen

    DEFF Research Database (Denmark)

    Wiese, Lars Ole

    2006-01-01

    I denne artikel diskuteres Activity Based Costing (ABC) som rapporterings-teknik for kunde profitabilitet. Der argumenteres for, at indtægtserhvervel-sen inkl. dens direkte omkostningsforbrug bør adskilles fra omkostnings-beskrivelsen til produktfremstilling. Dvs. der gennemføres en aktivitetsba......-seret rapportering for indtægter og en ABC model for omkostningsforbrug til produktfremstilling. Modellen er tilført logiske beslutningsobjekter (klas-sifikationer), som er opbygget niveaubaseret. Samtidigt føres belæg for, at ABC modellen bør baseres på logiske fordelinger til kalkulationsobjektet i stedet...

  15. A putative amino acid ABC transporter substrate-binding protein, NMB1612, from Neisseria meningitidis, induces murine bactericidal antibodies against meningococci expressing heterologous NMB1612 proteins.

    Science.gov (United States)

    Hung, Miao-Chiu; Humbert, María Victoria; Laver, Jay R; Phillips, Renee; Heckels, John E; Christodoulides, Myron

    2015-08-26

    The nmb1612 (NEIS1533) gene encoding the ~27-kDa putative amino acid ATP-binding cassette (ABC) transporter, periplasmic substrate-binding protein from Neisseria meningitidis serogroup B (MenB) strain MC58 was cloned and expressed in Escherichia coli, and the purified recombinant (r)NMB1612 was used for animal immunization studies. Immunization of mice with rNMB1612 adsorbed to Al(OH)3 and in liposomes with and without MPLA, induced antiserum with bactericidal activity in an assay using baby rabbit complement, against the homologous strain MC58 (encoding protein representative of Allele 62) and killed heterologous strains encoding proteins of three other alleles (representative of Alleles 1, 64 and 68), with similar SBA titres. However, strain MC58 was not killed (titre bactericidal assay (hSBA) using anti-rNMB1612 sera, although another strain (MC168) expressing the same protein was killed (median titres of 16-64 in the hSBA). Analysis of the NMB1612 amino acid sequences from 4351 meningococcal strains in the pubmlst.org/Neisseria database and a collection of 13 isolates from colonized individuals and from patients, showed that antibodies raised against rNMB1612 could potentially kill at least 72% of the MenB strains in the complete sequence database. For MenB disease occurring specifically in the UK from 2013 to 2015, >91% of the isolates causing disease in this recent period expressed NMB1612 protein encoded by Allele 1 and could be potentially killed by sera raised to the recombinant antigen in the current study. The NMB1612 protein was surface-accessible and expressed by different meningococcal strains. In summary, the properties of (i) NMB1612 protein conservation and expression, (ii) limited amino acid sequence variation between proteins encoded by different alleles, and (iii) the ability of a recombinant protein to induce cross-strain bactericidal antibodies, would all suggest a promising antigen for consideration for inclusion in new meningococcal vaccines

  16. Identification of ABC transporter genes conferring combined pleuromutilin-lincosamide-streptogramin A resistance in bovine methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci.

    Science.gov (United States)

    Wendlandt, Sarah; Kadlec, Kristina; Feßler, Andrea T; Schwarz, Stefan

    2015-06-12

    The aim of this study was to investigate the genetic basis of combined pleuromutilin-lincosamide-streptogramin A resistance in 26 unrelated methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (CoNS) from dairy cows suffering from mastitis. The 26 pleuromutilin-resistant staphylococcal isolates were screened for the presence of the genes vga(A), vga(B), vga(C), vga(E), vga(E) variant, sal(A), vmlR, cfr, lsa(A), lsa(B), lsa(C), and lsa(E) by PCR. None of the 26 isolates carried the genes vga(B), vga(C), vga(E), vga(E) variant, vmlR, cfr, lsa(A), lsa(B), or lsa(C). Two Staphylococcus haemolyticus and single Staphylococcus xylosus, Staphylococcus lentus, and Staphylococcus hominis were vga(A)-positive. Twelve S. aureus, two Staphylococcus warneri, as well as single S. lentus and S. xylosus carried the lsa(E) gene. Moreover, single S. aureus, S. haemolyticus, S. xylosus, and Staphylococcus epidermidis were positive for both genes, vga(A) and lsa(E). The sal(A) gene was found in a single Staphylococcus sciuri. All ABC transporter genes were located in the chromosomal DNA, except for a plasmid-borne vga(A) gene in the S. epidermidis isolate. The genetic environment of the lsa(E)-positive isolates was analyzed using previously described PCR assays. Except for the S. warneri and S. xylosus, all lsa(E)-positive isolates harbored a part of the previously described enterococcal multiresistance gene cluster. This is the first report of the novel lsa(E) gene in the aforementioned bovine CoNS species. This is also the first identification of the sal(A) gene in a S. sciuri from a case of bovine mastitis. Moreover, the sal(A) gene was shown to also confer pleuromutilin resistance. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. ABC proteins protect the human body and maintain optimal health.

    Science.gov (United States)

    Ueda, Kazumitsu

    2011-01-01

    Human MDR1, a multi-drug transporter gene, was isolated as the first of the eukaryote ATP Binding Cassette (ABC) proteins from a multidrug-resistant carcinoma cell line in 1986. To date, over 25 years, many ABC proteins have been found to play important physiological roles by transporting hydrophobic compounds. Defects in their functions cause various diseases, indicating that endogenous hydrophobic compounds, as well as water-soluble compounds, are properly transported by transmembrane proteins. MDR1 transports a large number of structurally unrelated drugs and is involved in their pharmacokinetics, and thus is a key factor in drug interaction. ABCA1, an ABC protein, eliminates excess cholesterol in peripheral cells by generating HDL. Because ABCA1 is a key molecule in cholesterol homeostasis, its function and expression are highly regulated. Eukaryote ABC proteins function on the body surface facing the outside and in organ pathways to adapt to the extracellular environment and protect the body to maintain optimal health.

  18. Type VI Secretion System Transports Zn2+ to Combat Multiple Stresses and Host Immunity.

    Directory of Open Access Journals (Sweden)

    Tietao Wang

    2015-07-01

    Full Text Available Type VI secretion systems (T6SSs are widespread multi-component machineries that translocate effectors into either eukaryotic or prokaryotic cells, for virulence or for interbacterial competition. Herein, we report that the T6SS-4 from Yersinia pseudotuberculosis displays an unexpected function in the transportation of Zn2+ to combat diverse stresses and host immunity. Environmental insults such as oxidative stress induce the expression of T6SS-4 via OxyR, the transcriptional factor that also regulates many oxidative response genes. Zinc transportation is achieved by T6SS-4-mediated translocation of a novel Zn2+-binding protein substrate YezP (YPK_3549, which has the capacity to rescue the sensitivity to oxidative stress exhibited by T6SS-4 mutants when added to extracellular milieu. Disruption of the classic zinc transporter ZnuABC together with T6SS-4 or yezP results in mutants that almost completely lost virulence against mice, further highlighting the importance of T6SS-4 in resistance to host immunity. These results assigned an unconventional role to T6SSs, which will lay the foundation for studying novel mechanisms of metal ion uptake by bacteria and the role of this process in their resistance to host immunity and survival in harmful environments.

  19. ABC's "Person of the Week": American Values in Television News.

    Science.gov (United States)

    Larson, Stephanie Greco; Bailey, Martha

    1998-01-01

    Contributes to scholarship on values and ideologies in the media by analyzing five years of ABC's "Person of the Week" segments to identify prominent types of people and values endorsed by mainstream news media. Finds that individuals most frequently selected for ABC's honor lived in the United States; worked in politics and…

  20. abc: An extensible AspectJ compiler

    DEFF Research Database (Denmark)

    Avgustinov, Pavel; Christensen, Aske Simon; Hendren, Laurie

    2005-01-01

    Research in the design of aspect-oriented programming languages requires a workbench that facilitates easy experimentation with new language features and implementation techniques. In particular, new features for AspectJ have been proposed that require extensions in many dimensions: syntax, type...... checking and code generation, as well as data flow and control flow analyses. The AspectBench Compiler (abc) is an implementation of such a workbench. The base version of abc implements the full AspectJ language. Its frontend is built, using the Polyglot framework, as a modular extension of the Java...... language. The use of Polyglot gives flexibility of syntax and type checking. The backend is built using the Soot framework, to give modular code generation and analyses. In this paper, we outline the design of abc, focusing mostly on how the design supports extensibility. We then provide a general overview...

  1. The role of the atypical kinases ABC1K7 and ABC1K8 in abscisic acid responses

    Directory of Open Access Journals (Sweden)

    Anna eManara

    2016-03-01

    Full Text Available The ABC1K family of atypical kinases (activity of bc1 complex kinase is represented in bacteria, archaea and eukaryotes. In plants they regulate diverse physiological processes in the chloroplasts and mitochondria, but their precise functions are poorly defined. ABC1K7 and ABC1K8 are probably involved in oxidative stress responses, isoprenyl lipid synthesis and distribution of iron within chloroplasts. Because reactive oxygen species take part in abscisic acid (ABA-mediated processes, we investigated the functions of ABC1K7 and ABC1K8 during germination, stomatal movement and leaf senescence. Both genes were upregulated by ABA treatment and some ABA-responsive physiological processes were affected in abc1k7 and abc1k8 mutants. Germination was more severely affected by ABA, osmotic stress and salt stress in the single and double mutants; the stomatal aperture was smaller in the mutants under standard growth conditions and was not further reduced by exogenous ABA application; ABA-induced senescence symptoms were more severe in the leaves of the single and double mutants compared to wild type leaves. Taken together, our results suggest that ABC1K7 and ABC1K8 might be involved in the cross-talk between ABA and ROS signaling.

  2. The Yeast ATP-binding Cassette (ABC) Transporter Ycf1p Enhances the Recruitment of the Soluble SNARE Vam7p to Vacuoles for Efficient Membrane Fusion*

    Science.gov (United States)

    Sasser, Terry L.; Lawrence, Gus; Karunakaran, Surya; Brown, Christopher; Fratti, Rutilio A.

    2013-01-01

    The Saccharomyces cerevisiae vacuole contains five ATP-binding cassette class C (ABCC) transporters, including Ycf1p, a family member that was originally characterized as a Cd2+ transporter. Ycf1p has also been found to physically interact with a wide array of proteins, including factors that regulate vacuole homeostasis. In this study, we examined the role of Ycf1p and other ABCC transporters in the regulation of vacuole homotypic fusion. We found that deletion of YCF1 attenuated in vitro vacuole fusion by up to 40% relative to wild-type vacuoles. Plasmid-expressed wild-type Ycf1p rescued the deletion phenotype; however, Ycf1p containing a mutation of the conserved Lys-669 to Met in the Walker A box of the first nucleotide-binding domain (Ycf1pK669M) was unable to complement the fusion defect of ycf1Δ vacuoles. This indicates that the ATPase activity of Ycf1p is required for its function in regulating fusion. In addition, we found that deleting YCF1 caused a striking decrease in vacuolar levels of the soluble SNARE Vam7p, whereas total cellular levels were not altered. The attenuated fusion of ycf1Δ vacuoles was rescued by the addition of recombinant Vam7p to in vitro experiments. Thus, Ycf1p contributes in the recruitment of Vam7p to the vacuole for efficient membrane fusion. PMID:23658021

  3. ABC's of Being Smart

    Science.gov (United States)

    Foster, Joanne

    2011-01-01

    Determining what giftedness is all about means focusing on many aspects of the individual. In this paper, the author focuses on letter D of the ABC's of being smart. She starts with specifics about giftedness (details), and then moves on to some ways of thinking (dispositions).

  4. Membrane porters of ATP-binding cassette transport systems are polyphyletic.

    Science.gov (United States)

    Wang, Bin; Dukarevich, Maxim; Sun, Eric I; Yen, Ming Ren; Saier, Milton H

    2009-09-01

    The ATP-binding cassette (ABC) superfamily consists of both importers and exporters. These transporters have, by tradition, been classified according to the ATP hydrolyzing constituents, which are monophyletic. The evolutionary origins of the transmembrane porter proteins/domains are not known. Using five distinct computer programs, we here provide convincing statistical data suggesting that the transmembrane domains of ABC exporters are polyphyletic, having arisen at least three times independently. ABC1 porters arose by intragenic triplication of a primordial two-transmembrane segment (TMS)-encoding genetic element, yielding six TMS proteins. ABC2 porters arose by intragenic duplication of a dissimilar primordial three-TMS-encoding genetic element, yielding a distinctive protein family, nonhomologous to the ABC1 proteins. ABC3 porters arose by duplication of a primordial four-TMS-encoding genetic element, yielding either eight- or 10-TMS proteins. We assign each of 48 of the 50 currently recognized families of ABC exporters to one of the three evolutionarily distinct ABC types. Currently available high-resolution structural data for ABC porters are fully consistent with our findings. These results provide guides for future structural and mechanistic studies of these important transport systems.

  5. Step 2: Know Your Diabetes ABCs

    Science.gov (United States)

    ... page please turn JavaScript on. Feature: Type 2 Diabetes Step 2: Know Your Diabetes ABCs Past Issues / Fall 2014 Table of Contents ... cholesterol helps remove cholesterol from your blood vessels. Diabetes HealthSense Find tools and programs that can help ...

  6. Inventory and analysis of ATP-binding cassette (ABC) systems in Brugia malayi.

    Science.gov (United States)

    Ardelli, B F; Stitt, L E; Tompkins, J B

    2010-07-01

    ABC systems are one of the largest described protein superfamilies. These systems have a domain organization that may contain 1 or more transmembrane domains (ABC_TM1F) and 1 or 2 ATP-binding domains (ABC_2). The functions (e.g., import, export and DNA repair) of these proteins distinguish the 3 classes of ABC systems. Mining and PCR-based cloning were used to identify 33 putative ABC systems from the Brugia malayi genome. There were 31 class 2 genes, commonly called ABC transporters, and 2 class 3 genes. The ABC transporters were divided into subfamilies. Three belonged to subfamily A, 16 to subfamily B, 5 to subfamily C, 1 to subfamily E and 3 to subfamilies F and G, respectively. None were placed in subfamilies D and H. Similar to other ABC systems, the ABC_2 domain of B. malayi genes was conserved and contained the Walker A and B motifs, the signature sequence/linker region and the switch region with the conserved histidine. The ABC_TM1F domain was less conserved. The relative abundance of ABC systems was quantified using real-time reverse transcription PCR and was significantly higher in female adults of B. malayi than in males and microfilaria, particularly those in subfamilies B and C, which are associated with drug resistance.

  7. [Research progress in chondroitinase ABC].

    Science.gov (United States)

    Li, Ye; Chen, Zhenya; Yuan, Qipeng

    2015-05-01

    As the components of proteoglycans, glycosaminoglycans (GAGs) are linear polysaccharides consisting of hexose and uronic acid units linked by β-1,3-glycosidic bond. GAGs mainly distribute in extracellular matrix and on cell surfaces. They guide many biological processes, such as proliferation of cells, transmission of signals and mediation of inflammation. Because of their large molecular weights, GAGs have limited biological functions in vitro. However, the appearance of chondroitinase ABC (ChSase ABC), which can lyse polysaccharides, solves the difficulties. Based on our work, we summarized the classification and the crystal structure of ChSase ABC, as well as other recent research progress on ChSase ABCs. The separation and purification methods of ChSase ABC and construction of engineering bacteria are illustrated. The stability and immobilization are also analyzed by taking account of the characterization of ChSase ABC. Finally, problems and future prospect of the ChSase ABC study are summarized.

  8. A burst of ABC genes in the genome of the polyphagous spider mite Tetranychus urticae

    Science.gov (United States)

    2013-01-01

    Background The ABC (ATP-binding cassette) gene superfamily is widespread across all living species. The majority of ABC genes encode ABC transporters, which are membrane-spanning proteins capable of transferring substrates across biological membranes by hydrolyzing ATP. Although ABC transporters have often been associated with resistance to drugs and toxic compounds, within the Arthropoda ABC gene families have only been characterized in detail in several insects and a crustacean. In this study, we report a genome-wide survey and expression analysis of the ABC gene superfamily in the spider mite, Tetranychus urticae, a chelicerate ~ 450 million years diverged from other Arthropod lineages. T. urticae is a major agricultural pest, and is among of the most polyphagous arthropod herbivores known. The species resists a staggering array of toxic plant secondary metabolites, and has developed resistance to all major classes of pesticides in use for its control. Results We identified 103 ABC genes in the T. urticae genome, the highest number discovered in a metazoan species to date. Within the T. urticae ABC gene set, all members of the eight currently described subfamilies (A to H) were detected. A phylogenetic analysis revealed that the high number of ABC genes in T. urticae is due primarily to lineage-specific expansions of ABC genes within the ABCC, ABCG and ABCH subfamilies. In particular, the ABCC subfamily harbors the highest number of T. urticae ABC genes (39). In a comparative genomic analysis, we found clear orthologous relationships between a subset of T. urticae ABC proteins and ABC proteins in both vertebrates and invertebrates known to be involved in fundamental cellular processes. These included members of the ABCB-half transporters, and the ABCD, ABCE and ABCF families. Furthermore, one-to-one orthologues could be distinguished between T. urticae proteins and human ABCC10, ABCG5 and ABCG8, the Drosophila melanogaster sulfonylurea receptor and ecdysone

  9. Transport of iodothyronines by human l-type amino acid transporters

    NARCIS (Netherlands)

    C. Zevenbergen (Chantal); M.E. Meima (Marcel); E.C.L. De Souza; R.P. Peeters (Robin); Kinne, A. (Anita); Krause, G. (Gerd); W. Edward Visser (W.); T.J. Visser (Theo)

    2015-01-01

    textabstractThyroid hormone (TH) transporters facilitate cellular TH influx and efflux, which is paramount for normal physiology. The L-type amino acid transporters LAT1 and LAT2 are known to facilitate TH transport. However, the role of LAT3, LAT4, and LAT5 is still unclear. Therefore, the aim of

  10. Evolutionary relationships of ATP-Binding Cassette (ABC) uptake porters.

    Science.gov (United States)

    Zheng, Wei Hao; Västermark, Åke; Shlykov, Maksim A; Reddy, Vamsee; Sun, Eric I; Saier, Milton H

    2013-05-06

    The ATP-Binding Cassette (ABC) functional superfamily includes integral transmembrane exporters that have evolved three times independently, forming three families termed ABC1, ABC2 and ABC3, upon which monophyletic ATPases have been superimposed for energy-coupling purposes [e.g., J Membr Biol 231(1):1-10, 2009]. The goal of the work reported in this communication was to understand how the integral membrane constituents of ABC uptake transporters with different numbers of predicted or established transmembrane segments (TMSs) evolved. In a few cases, high resolution 3-dimensional structures were available, and in these cases, their structures plus primary sequence analyses allowed us to predict evolutionary pathways of origin. All of the 35 currently recognized families of ABC uptake proteins except for one (family 21) were shown to be homologous using quantitative statistical methods. These methods involved using established programs that compare native protein sequences with each other, after having compared each sequence with thousands of its own shuffled sequences, to gain evidence for homology. Topological analyses suggested that these porters contain numbers of TMSs ranging from four or five to twenty. Intragenic duplication events occurred multiple times during the evolution of these porters. They originated from a simple primordial protein containing 3 TMSs which duplicated to 6 TMSs, and then produced porters of the various topologies via insertions, deletions and further duplications. Except for family 21 which proved to be related to ABC1 exporters, they are all related to members of the previously identified ABC2 exporter family. Duplications that occurred in addition to the primordial 3 → 6 duplication included 5 → 10, 6 → 12 and 10 → 20 TMSs. In one case, protein topologies were uncertain as different programs gave discrepant predictions. It could not be concluded with certainty whether a 4 TMS ancestral protein or a 5 TMS ancestral protein

  11. Effect of Walker A mutation (K86M) on oligomerization and surface targeting of the multidrug resistance transporter ABCG2

    DEFF Research Database (Denmark)

    Henriksen, Ulla Birk; Gether, Ulrik; Litman, Thomas

    2005-01-01

    of the nucleotide binding domain (NBD) known to be critical for ATP binding and/or hydrolysis in ABC transporters. The mutant (ABCG2-K86M) was inactive as expected but was expressed at similar levels as the wild-type (wt) protein. The mutation did not affect the predicted oligomerization properties......The ATP binding cassette (ABC) half-transporter ABCG2 (MXR/BCRP/ABCP) is associated with mitoxantrone resistance accompanied by cross-resistance to a broad spectrum of cytotoxic drugs. Here we investigate the functional consequences of mutating a highly conserved lysine in the Walker A motif...... of the NBDs in assisting proper surface targeting of ABC transporters....

  12. A Type Calculus for Mathematical Programming Modeling Languages

    Science.gov (United States)

    1990-09-01

    verification, the APPLY-OPERATOR procedure 60 TABLE 4.8 EQUIVALENT EXPRESSIONS Infix Prefix Postfix a a a a+b +ab ab+ a+b-c -+ abc ab+c- a+(b-c) +a-bc... abc -+ a/b/c / abc ab/c/ a*b-c -* abc ab*c- a*(b-c) *a-bc abc -* a+b*c-d +a-*bcd abc *+d- (a+b)*(c-d) *+ab-cd ab+cd-* manipulates canonical types...FUNCTIONS OBJECTIVE: SUM(J,k) {ACTIVITY (PROD COSTQ~k) *PRODU,k) + FAG COSTO ,k) OPEN FAC(J,k)) *+ SUMQ(k) {PLANT) (PLANT-COST(k) * OPENLANT(k)); CONSTRAINTS

  13. Milder phenotypes of glucose transporter type 1 deficiency syndrome

    NARCIS (Netherlands)

    Anand, G.; Padeniya, A.; Hanrahan, D.; Scheffer, H.; Zaiwalla, Z.; Cox, D.; Mann, N.; Hewertson, J.; Price, S.; Nemeth, A.; Arsov, T.; Scheffer, I.; Jayawant, S.; Pike, M.; McShane, T.

    2011-01-01

    Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a treatable condition resulting from impaired glucose transport into the brain. The classical presentation is with infantile-onset epilepsy and severe developmental delay. Non-classical phenotypes with movement disorders and early-onset

  14. The capacity of Listeria monocytogenes mutants with in-frame deletions in putative ATP-binding cassette transporters to form biofilms and comparison with the wild type

    Directory of Open Access Journals (Sweden)

    Marina Ceruso

    2014-02-01

    Full Text Available Listeria monocytogenes (Lm is a food-borne pathogen responsible for human listeriosis, an invasive infection with high mortality rates. Lm has developed efficient strategies for survival under stress conditions such as starvation and wide variations in temperature, pH, and osmolarity. Therefore, Lm can survive in food under multiple stress conditions. Detailed studies to determine the mode of action of this pathogen for survival under stress conditions are important to control Lm in food. It has been shown that genes encoding for ATP-binding cassette (ABC transporters are induced in Lm in food, in particular under stress conditions. Previous studies showed that these genes are involved in sensitivity to nisin, acids, and salt. The aim of this study was to determine the involvement of some ABC transporters in biofilm formation. Therefore, deletion mutants of ABC transporter genes (LMOf2365_1875 and LMOf2365_1877 were created in Lm F2365, and then were compared to the wild type for their capacity to form biofilms. Lm strain F2365 was chosen as reference since the genome is fully sequenced and furthermore this strain is particularly involved in food-borne outbreaks of listeriosis. Our results showed that DLMOf2365_1875 had an increased capacity to form biofilms compared to the wild type, indicating that LMOf2365_1875 negatively regulates biofilm formation. A deeper knowledge on the ability to form biofilms in these mutants may help in the development of intervention strategies to control Lm in food and in the environment.

  15. Purification and crystallization of the ABC-type transport substrate-binding protein OppA from Thermoanaerobacter tengcongensis

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Jinlan; Li, Xiaolu [State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Tsinghua University, Beijing 100005, People' s Republic of China (China); Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, People' s Republic of China (China); Feng, Yue; Zhang, Bo [Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, People' s Republic of China (China); Miao, Shiying [State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Tsinghua University, Beijing 100005, People' s Republic of China (China); Wang, Linfang, E-mail: lfwangz@yahoo.com [State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Tsinghua University, Beijing 100005, People' s Republic of China (China); Wang, Na, E-mail: nawang@tsinghua.edu.cn [Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, People' s Republic of China (China)

    2012-06-22

    Highlights: Black-Right-Pointing-Pointer We truncated the signal peptide of OppA{sub TTE0054} to make it express in Escherichia coli as a soluble protein. Black-Right-Pointing-Pointer Crystals of OppA{sub TTE0054} were grown by sitting-drop vapor diffusion method. Black-Right-Pointing-Pointer The crystal of OppA{sub TTE0054} diffracted to 2.25 A. -- Abstract: Di- and oligopeptide- binding protein OppAs play important roles in solute and nutrient uptake, sporulation, biofilm formation, cell wall muropeptides recycling, peptide-dependent quorum-sensing responses, adherence to host cells, and a variety of other biological processes. Soluble OppA from Thermoanaerobacter tengcongensis was expressed in Escherichia coli. The protein was found to be >95% pure with SDS-PAGE after a series of purification steps and the purity was further verified by mass spectrometry. The protein was crystallized using the sitting-drop vapour-diffusion method with PEG 400 as the precipitant. Crystal diffraction extended to 2.25 A. The crystal belonged to space group C222{sub 1}, with unit-cell parameters of a = 69.395, b = 199.572, c = 131.673 A, and {alpha} = {beta} = {gamma} = 90 Degree-Sign .

  16. Flavonoid-mediated inhibition of intestinal ABC transporters may affect the oral bioavailability of drugs, food-borne toxic compounds and bioactive ingredients

    NARCIS (Netherlands)

    Brand, W.; Schutte, M.E.; Williamson, G.; Zanden, J.J. van; Cnubben, N.H.P.; Groten, J.P.; Bladeren, P.J. van; Rietjens, I.M.C.M.

    2006-01-01

    The transcellular transport of ingested food ingredients across the intestinal epithelial barrier is an important factor determining bioavailability upon oral intake. This transcellular transport of many chemicals, food ingredients, drugs or toxic compounds over the intestinal epithelium can be

  17. Thermodynamics of the ATPase cycle of GlcV, the nucleotide-binding domain of the glucose ABC transporter of Sulfolobus solfataricus

    NARCIS (Netherlands)

    Pretz, Monika G.; Albers, Sonja-Verena; Schuurman-Wolters, Gea; Tampe, Robert; Driessen, Arnold J. M.; van der Does, Chris

    2006-01-01

    ATP-binding cassette transporters drive the transport of substrates across the membrane by the hydrolysis of ATP. They typically have a conserved domain structure with two membrane-spanning domains that form the transport channel and two cytosolic nucleotide-binding domains ( NBDs) that energize the

  18. LrABCF1, a GCN-type ATP-binding cassette transporter from Lilium regale, is involved in defense responses against viral and fungal pathogens.

    Science.gov (United States)

    Sun, Daoyang; Zhang, Xinguo; Li, Shaohua; Jiang, Cai-Zhong; Zhang, Yanlong; Niu, Lixin

    2016-12-01

    The L. regale ATP-binding cassette transporter gene, LrABCF1 belonging to GCN subfamily, functions as a positive regulator of plant defense against Cucumber mosaic virus, Tobacco rattle virus , and Botrytis cinerea in petunia. ATP-binding cassette (ABC) transporters are essential for membrane translocation in diverse biological processes, such as plant development and defense response. Here, a general control non-derepressible (GCN)-type ABC transporter gene, designated LrABCF1, was identified from Cucumber mosaic virus (CMV)-induced cDNA library of L. regale. LrABCF1 was up-regulated upon inoculation with CMV and Lily mottle virus (LMoV). Salicylic acid (SA) and ethylene (ET) application and treatments with abiotic stresses such as cold, high salinity, and wounding increased the transcript abundances of LrABCF1. Constitutive overexpression of LrABCF1 in petunia (Petunia × hybrida) resulted in an impairment of plant growth and development. LrABCF1 overexpression conferred reduced susceptibility to CMV, Tobacco rattle virus (TRV), and B. cinerea infection in transgenic petunia plants, accompanying by elevated transcripts of PhGCN2 and a few defense-related genes in SA-signaling pathway. Our data indicate that LrABCF1 positively modulates viral and fungal resistance.

  19. Curva ABC de fornecedores

    OpenAIRE

    Solano, Renato da Silva

    2003-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção. Este trabalho faz uma revisão e busca dar uma contribuição aos gerentes de Planejamento, Programação, Controle e Gerenciamento de Empreendimentos e Obras através do uso das Curvas ABC. O trabalho utilizou 10 empreendimentos de classificação Alta (NBR 12721), incorporados por oito empresas do setor e fez uma análise dos projetos-padrão da NBR 12721. Foi f...

  20. Do You Know Your ABC?

    Science.gov (United States)

    Neale, Claire

    2013-01-01

    Within primary schools, the core subjects of literacy and numeracy are highly regarded, and rightly so, as children need to learn to read, write and be numerically literate. This means that all children learn their ABCs at an early age, But, what about the "other ABC"--"Airway, Breathing and Circulation?" Accidents and medical…

  1. The putative response regulator BaeR stimulates multidrug resistance of Escherichia coli via a novel multidrug exporter system, MdtABC.

    Science.gov (United States)

    Nagakubo, Satoshi; Nishino, Kunihiko; Hirata, Takahiro; Yamaguchi, Akihito

    2002-08-01

    Overproduction of the response regulator BaeR confers resistance to novobiocin and bile salts in a DeltaacrAB mutant by stimulating drug exporter gene expression. The mdtABC (multidrug transporter ABC, formerly known as yegMNO) genes, which encode a resistance-nodulation-cell division (RND) drug efflux system, are responsible for resistance. The MdtABC system comprises the transmembrane MdtB/MdtC heteromultimer and MdtA membrane fusion protein. MdtAC also confers bile salt, but not novobiocin, resistance. This indicates that the evolution from an MdtC homomultimer to an MdtBC heteromultimer contributed to extend the drug resistance spectrum. A BLAST search suggested that such a heteromultimer-type RND exporter constitutes a unique family among gram-negative organisms.

  2. Genome-wide comparative analysis of ABC systems in the Bdellovibrio-and-like organisms.

    Science.gov (United States)

    Li, Nan; Chen, Huan; Williams, Henry N

    2015-05-10

    Bdellovibrio-and-like organisms (BALOs) are gram-negative, predatory bacteria with wide variations in genome sizes and GC content and ecological habitats. The ATP-binding cassette (ABC) systems have been identified in several prokaryotes, fungi and plants and have a role in transport of materials in and out of cells and in cellular processes. However, knowledge of the ABC systems of BALOs remains obscure. A total of 269 putative ABC proteins were identified in BALOs. The genes encoding these ABC systems occupy nearly 1.3% of the gene content in freshwater Bdellovibrio strains and about 0.7% in their saltwater counterparts. The proteins found belong to 25 ABC system families based on their structural characteristics and functions. Among these, 16 families function as importers, 6 as exporters and 3 are involved in various cellular processes. Eight of these 25 ABC system families were deduced to be the core set of ABC systems conserved in all BALOs. All Bacteriovorax strains have 28 or less ABC systems. On the contrary, the freshwater Bdellovibrio strains have more ABC systems, typically around 51. In the genome of Bdellovibrio exovorus JSS (CP003537.1), 53 putative ABC systems were detected, representing the highest number among all the BALO genomes examined in this study. Unexpected high numbers of ABC systems involved in cellular processes were found in all BALOs. Phylogenetic analysis suggests that the majority of ABC proteins can be assigned into many separate families with high bootstrap supports (>50%). In this study, a general framework of sequence-structure-function connections for the ABC systems in BALOs was revealed providing novel insights for future investigations. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Genome organisation and expression profiling of ABC protein-encoding genes in Heterobasidion annosum s.l. complex.

    Science.gov (United States)

    Baral, Bikash; Kovalchuk, Andriy; Asiegbu, Fred O

    2016-03-01

    Members of Heterobasidion annosum species complex are widely regarded as the most destructive fungal pathogens of conifer trees in the boreal and temperate zones of Northern hemisphere. To invade and colonise their host trees, Heterobasidion fungi must overcome components of host chemical defence, including terpenoid oleoresin and phenolic compounds. ABC transporters may play an important role in this process participating in the export of toxic host metabolites and maintaining their intracellular concentration below the critical level. We have identified and phylogenetically classified Heterobasidion genes encoding ABC transporters and closely related ABC proteins. The number of ABC proteins in the Heterobasidion genome is one of the lowest among analysed species of Agaricomycotina. Using quantitative RT-PCR, we have analysed transcriptional response of Heterobasidion ABC transporter-encoding genes to monoterpenes as well as their expression profile during growth on pine wood in comparison to the growth on defined media. Several ABC transporters were up-regulated during growth on pine wood. The ABC-transporter encoding gene ABCG1.1 was induced both during growth of H. annosum on pine wood and upon exposure to monoterpenes. Our experimental data demonstrate the differential responses of Heterobasidion ABC genes to growth conditions and chemical stressors. The presented results suggest a potential role of Heterobasidion ABC-G transporters in the resistance to the components of conifer chemical defence. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  4. The chemistry of ABC

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, R.J. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    ABC stand for accelerator based conversion of Pu. It is a unique approach to Pu destruction that allows for a well controlled and complete burn of Pu as may be required by treaty or policy. The central idea of the approach is to provide a spallation source of neutrons that allows the operation of a fissioning system without a critical mass and at a K effective less than one. Material to be fissioned is suspended in a molten salt medium for high temperature control and on-line removal of neutron absorbing fission products. This paper discusses the issues associated with the selection and operation of a molten salt chemical system: redox control, product removal, material feed, solubilities, deposition control, and a host of operational procedures.

  5. The Role of RaxST, a Prokaryotic Sulfotransferase, and RaxABC, a Putative Type I Secretion System, in Activation of the Rice XA21-Mediated Immune Response

    Directory of Open Access Journals (Sweden)

    Pamela C. Ronald

    2014-01-01

    Full Text Available Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals. We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo carries a functional sulfotransferase (RaxST. raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction. The raxST gene resides in the same operon (raxSTAB as components of a predicted type I secretion and processing system (RaxA and RaxB. These observations suggest a model where RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.

  6. The domain II loops of Bacillus thuringiensis Cry1Aa form an overlapping interaction site for two Bombyx mori larvae functional receptors, ABC transporter C2 and cadherin-like receptor.

    Science.gov (United States)

    Adegawa, Satomi; Nakama, Yui; Endo, Haruka; Shinkawa, Naoki; Kikuta, Shingo; Sato, Ryoichi

    2017-02-01

    Information about the receptor-interaction region of Cry toxins, insecticidal proteins produced by Bacillus thuringiensis, is needed to elucidate the mode of action of Cry toxins and improve their toxicity through protein engineering. We analyzed the interaction sites on Cry1Aa with ABC transporter C2 (ABCC2), one of the most important Cry1A toxin receptors. A competitive binding assay revealed that the Bombyx mori ABCC2 (BmABCC2) Cry1A binding site was the same as the BtR175 binding site, suggesting that the loop region of Cry1Aa domain II is a binding site. Next, we constructed several domain II loop mutant toxins and tested their binding affinity in an SPR analysis, and also performed a cell swelling assay to evaluate receptor-mediated cytotoxicity. Our results indicate that the loop regions required for BtR175 and BmABCC2 binding and the regions important for cytotoxicity partially overlap. Our results also suggest that receptor binding is necessary but not sufficient for cytotoxicity. This is the first report showing the region of interaction between ABCC2 and Cry1Aa and the cytotoxicity-relevant properties of the Cry1Aa domain II loop region. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Purification, crystallization and preliminary X-ray analysis of the galacto-N-biose-/lacto-N-biose I-binding protein (GL-BP) of the ABC transporter from Bifidobacterium longum JCM1217

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Jun [Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Suzuki, Ryuichiro; Fushinobu, Shinya [Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan); Kitaoka, Motomitsu [National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642 (Japan); Wakagi, Takayoshi; Shoun, Hirofumi [Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657 (Japan); Ashida, Hisashi [Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Kumagai, Hidehiko; Katayama, Takane, E-mail: takane@ishikawa-pu.ac.jp [Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836 (Japan); Yamamoto, Kenji [Graduate School of Biostudies, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

    2007-09-01

    Preliminary X-ray analysis of the galacto-N-biose-/lacto-N-biose I-binding protein (GL-BP) of the ABC transporter from B. longum is described. A recombinant galacto-N-biose-/lacto-N-biose I-binding protein (GL-BP) from Bifidobacterium longum JCM1217 has been prepared and crystallized by the hanging-drop vapour-diffusion method using 10 mg ml{sup −1} purified enzyme, 0.01 M zinc sulfate, 0.1 M MES buffer pH 5.9–6.4 and 20–22%(v/v) PEG MME 550 in the presence of 5 mM disaccharide ligands. Suitable crystals grew after 10 d incubation at 293 K. The crystals belong to space group C222{sub 1}, with unit-cell parameters a = 106.3, b = 143.6, c = 114.6 Å for the lacto-N-biose I complex and a = 106.4, b = 143.4, c = 115.5 Å for the galacto-N-biose complex, and diffracted to 1.85 and 1.99 Å resolution, respectively.

  8. Transport of Iodothyronines by Human L-Type Amino Acid Transporters.

    Science.gov (United States)

    Zevenbergen, Chantal; Meima, Marcel E; Lima de Souza, Elaine C; Peeters, Robin P; Kinne, Anita; Krause, Gerd; Visser, W Edward; Visser, Theo J

    2015-11-01

    Thyroid hormone (TH) transporters facilitate cellular TH influx and efflux, which is paramount for normal physiology. The L-type amino acid transporters LAT1 and LAT2 are known to facilitate TH transport. However, the role of LAT3, LAT4, and LAT5 is still unclear. Therefore, the aim of this study was to further characterize TH transport by LAT1 and LAT2 and to explore possible TH transport by LAT3, LAT4, and LAT5. FLAG-LAT1-5 constructs were transiently expressed in COS1 cells. LAT1 and LAT2 were cotransfected with the CD98 heavy chain. Cellular transport was measured using 10 nM (125)I-labeled T4, T3, rT3, 3,3'-T2, and 10 μM [(125)I]3'-iodotyrosine (MIT) as substrates. Intracellular metabolism of these substrates was determined in cells cotransfected with either of the LATs with type 1 or type 3 deiodinase. LAT1 facilitated cellular uptake of all substrates and LAT2 showed a net uptake of T3, 3,3'-T2, and MIT. Expression of LAT3 or LAT4 did not affect transport of T4 and T3 but resulted in the decreased cellular accumulation of 3,3'-T2 and MIT. LAT5 did not facilitate the transport of any substrate. Cotransfection with LAT3 or LAT4 strongly diminished the cellular accumulation of 3,3'-T2 and MIT by LAT1 and LAT2. These data were confirmed by metabolism studies. LAT1 and LAT2 show distinct preferences for the uptake of the different iodocompounds, whereas LAT3 and LAT4 specifically facilitate the 3,3'-T2 and MIT efflux. Together our findings suggest that different sets of transporters with specific influx or efflux capacities may cooperate to regulate the cellular thyroid state.

  9. The Arabidopsis thaliana ABC protein superfamily, a complete inventory.

    Science.gov (United States)

    Sánchez-Fernández, R; Davies, T G; Coleman, J O; Rea, P A

    2001-08-10

    We describe the first complete inventory of ATP-binding cassette (ABC) proteins from a multicellular organism, the model plant Arabidopsis thaliana. By the application of several search criteria, Arabidopsis was found to contain a total of 129 open reading frames (ORFs) capable of encoding ABC proteins, of which 103 possessed contiguous transmembrane spans and were identified as putative intrinsic membrane proteins. Fifty-two of the putative intrinsic membrane proteins contained at least two transmembrane domains (TMDs) and two nucleotide-binding folds (NBFs) and could be classified as belonging to one of five subfamilies of full-molecule transporters. The other 51 putative membrane proteins, all of which were half-molecule transporters, fell into five subfamilies. Of the remaining ORFs identified, all of which encoded proteins lacking TMDs, 11 could be classified into three subfamilies. There were no obvious homologs in other organisms for 15 of the ORFs which encoded a heterogeneous group of non-intrinsic ABC proteins (NAPs). Unrooted phylogenetic analyses substantiated the subfamily designations. Notable features of the Arabidopsis ABC superfamily was the presence of a large yeast-like PDR subfamily, and the absence of genes encoding bona fide cystic fibrosis transmembrane conductance regulator (CFTR), sulfonylurea receptor (SUR), and heavy metal tolerance factor 1 (HMT1) homologs. Arabidopsis was unusual in its large allocation of ORFs (a minimum of 0.5%) to members of the ABC protein superfamily.

  10. Applying ABC Analysis to the Navy’s Inventory Management System

    Science.gov (United States)

    2014-09-01

    TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE APPLYING ABC ANALYSIS TO THE NAVY’S INVENTORY MANAGEMENT SYSTEM 5. FUNDING NUMBERS 6...Parts, Navy Enterprise Resource Planning, ABC Inventory Classification. 15. NUMBER OF PAGES 101 16. PRICE CODE 17. SECURITY CLASSIFICATION OF...for public release; distribution is unlimited APPLYING ABC ANALYSIS TO THE NAVY’S INVENTORY MANAGEMENT SYSTEM Benjamin May Lieutenant

  11. Uptake of L-cystine via an ABC transporter contributes defense of oxidative stress in the L-cystine export-dependent manner in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Iwao Ohtsu

    Full Text Available Intracellular thiols like L-cystine and L-cystine play a critical role in the regulation of cellular processes. Here we show that Escherichia coli has two L-cystine transporters, the symporter YdjN and the ATP-binding cassette importer FliY-YecSC. These proteins import L-cystine, an oxidized product of L-cystine from the periplasm to the cytoplasm. The symporter YdjN, which is expected to be a new member of the L-cystine regulon, is a low affinity L-cystine transporter (Km = 1.1 μM that is mainly involved in L-cystine uptake from outside as a nutrient. E. coli has only two L-cystine importers because ΔydjNΔyecS mutant cells are not capable of growing in the minimal medium containing L-cystine as a sole sulfur source. Another protein YecSC is the FliY-dependent L-cystine transporter that functions cooperatively with the L-cystine transporter YdeD, which exports L-cystine as reducing equivalents from the cytoplasm to the periplasm, to prevent E. coli cells from oxidative stress. The exported L-cystine can reduce the periplasmic hydrogen peroxide to water, and then generated L-cystine is imported back into the cytoplasm via the ATP-binding cassette transporter YecSC with a high affinity to L-cystine (Km = 110 nM in a manner dependent on FliY, the periplasmic L-cystine-binding protein. The double disruption of ydeD and fliY increased cellular levels of lipid peroxides. From these findings, we propose that the hydrogen peroxide-inducible L-cystine/L-cystine shuttle system plays a role of detoxification of hydrogen peroxide before lipid peroxidation occurs, and then might specific prevent damage to membrane lipids.

  12. The ABCs of Sex Ed.

    Science.gov (United States)

    Sroka, Stephen R.

    2002-01-01

    Cites statistics on extent of sexually transmitted diseases and pregnancies among adolescents; describes ideological dispute over how to teach sex education; advocates teaching the ABCs of sex education: Abstinence, Be Monogamous, and Condoms. (PKP)

  13. Politseiniku lustlik ABC / Pekka Erelt

    Index Scriptorium Estoniae

    Erelt, Pekka, 1965-

    1999-01-01

    Politsei on välja andnud 'Politseiniku ABC', mis antakse igale politseinikule. Karikaturist Heiki Ernits on peaaegu igale taskuraamatu leheküljele joonistanud pildikese mundrimeestest kentsakates situatsioonides.

  14. Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Svenningsen, Katrine; Knudsen, Lina Almind

    2015-01-01

    transporter proteins, inflammatory bowel disease, ulcerative, colitis, Crohns disease, colorectal cancer, colitis, intestinal inflammation, intestinal carcinogenesis, ABCB1/P-glycoprotein (P-gp/CD243/MDR1), ABCC2/multidrug resistance protein 2 (MRP2) and ABCG2/breast cancer resistance protein (BCRP), Abcb1...... with glucocorticoids. The evidence for the involvement of ABCC2 and ABCG2 in colonic pathophysiology was weak. CONCLUSION: ABCB1, diet, and gut microbes mutually interact in colonic inflammation, a well-known risk factor for CRC. Further insight may be translated into preventive and treatment strategies....... pathogen-free Abcb1 KO mice. The Abcb1 KO mice might thus serve as a model in which diet/environmental factors and microbes may be controlled and investigated in relation to intestinal inflammation. Potential molecular mechanisms include defective transport of inflammatory mediators and/or phospholipid...

  15. The yeast ABC transporter Pdr18 (ORF YNR070w) controls plasma membrane sterol composition, playing a role in multidrug resistance

    Science.gov (United States)

    Cabrito, Tânia R.; Teixeira, Miguel C.; Singh, Ashutosh; Prasad, Rajendra; Sá-Correia, Isabel

    2011-01-01

    The action of multidrug efflux pumps in MDR (multidrug resistance) acquisition has been proposed to partially depend on the transport of physiological substrates which may indirectly affect drug partition and transport across cell membranes. In the present study, the PDR18 gene [ORF (open reading frame) YNR070w], encoding a putative PDR (pleiotropic drug resistance) transporter of the ATP-binding cassette superfamily, was found to mediate plasma membrane sterol incorporation in yeast. The physiological role of Pdr18 is demonstrated to affect plasma membrane potential and is proposed to underlie its action as a MDR determinant, conferring resistance to the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid). The action of Pdr18 in yeast tolerance to 2,4-D, which was found to contribute to reduce [14C]2,4-D intracellular accumulation, may be indirect, given the observation that 2,4-D exposure deeply affects the sterol plasma membrane composition, this effect being much stronger in a Δpdr18 background. PDR18 activation under 2,4-D stress is regulated by the transcription factors Nrg1, controlling carbon source availability and the stress response, and, less significantly, Yap1, involved in oxidative stress and MDR, and Pdr3, a key regulator of the yeast PDR network, consistent with a broad role in stress defence. Taken together, the results of the present study suggest that Pdr18 plays a role in plasma membrane sterol incorporation, this physiological trait contributing to an MDR phenotype. PMID:21831043

  16. Accelerated bridge construction (ABC) decision making and economic modeling tool.

    Science.gov (United States)

    2011-12-01

    In this FHWA-sponsored pool funded study, a set of decision making tools, based on the Analytic Hierarchy Process (AHP) was developed. This tool set is prepared for transportation specialists and decision-makers to determine if ABC is more effective ...

  17. Genome-Wide Identification and Expression Profiling of ATP-Binding Cassette (ABC Transporter Gene Family in Pineapple (Ananas comosus (L. Merr. Reveal the Role of AcABCG38 in Pollen Development

    Directory of Open Access Journals (Sweden)

    Piaojuan Chen

    2017-12-01

    Full Text Available Pineapple (Ananas comosus L. cultivation commonly relies on asexual reproduction which is easily impeded by many factors in agriculture production. Sexual reproduction might be a novel approach to improve the pineapple planting. However, genes controlling pineapple sexual reproduction are still remain elusive. In different organisms a conserved superfamily proteins known as ATP binding cassette (ABC participate in various biological processes. Whereas, till today the ABC gene family has not been identified in pineapple. Here 100 ABC genes were identified in the pineapple genome and grouped into eight subfamilies (5 ABCAs, 20 ABCBs, 16 ABCCs, 2 ABCDs, one ABCEs, 5 ABCFs, 42 ABCGs and 9 ABCIs. Gene expression profiling revealed the dynamic expression pattern of ABC gene family in various tissues and different developmental stages. AcABCA5, AcABCB6, AcABCC4, AcABCC7, AcABCC9, AcABCG26, AcABCG38 and AcABCG42 exhibited preferential expression in ovule and stamen. Over-expression of AcABCG38 in the Arabidopsis double mutant abcg1-2abcg16-2 partially restored its pollen abortion defects, indicating that AcABCG38 plays important roles in pollen development. Our study on ABC gene family in pineapple provides useful information for developing sexual pineapple plantation which could be utilized to improve pineapple agricultural production.

  18. Aging management assessment of type B transportation packages

    International Nuclear Information System (INIS)

    Sullivan, G.J.; Stahmer, U.; Freeman, E.L.

    2004-01-01

    The condition of a physical system such as a radioactive materials transportation package can change as it ages. The degree to which aging effects are identified, prevented or mitigated will depend on the types of inspections and maintenance performed on the critical components of the system. Routine inspections and maintenance may not address degradation mechanisms that are difficult to observe and can act over long periods of time. Aging management is a systematic effort to ensure that the system performs as designed over its entire service life and that degradation mechanisms do not prematurely end the service life. The Nuclear Waste Management Division (NWMD) of Ontario Power Generation (OPG) has developed an Aging Management Procedure and began performing aging management assessments on its Type B(U) packages. This paper discusses the Procedure and briefly describes the aging management assessment performed on the Roadrunner Transportation Package to demonstrate a practical application of the aging management process

  19. A Survey of the ATP-Binding Cassette (ABC Gene Superfamily in the Salmon Louse (Lepeophtheirus salmonis.

    Directory of Open Access Journals (Sweden)

    Greta Carmona-Antoñanzas

    Full Text Available Salmon lice, Lepeophtheirus salmonis (Krøyer, 1837, are fish ectoparasites causing significant economic damage in the mariculture of Atlantic salmon, Salmo salar Linnaeus, 1758. The control of L. salmonis at fish farms relies to a large extent on treatment with anti-parasitic drugs. A problem related to chemical control is the potential for development of resistance, which in L. salmonis is documented for a number of drug classes including organophosphates, pyrethroids and avermectins. The ATP-binding cassette (ABC gene superfamily is found in all biota and includes a range of drug efflux transporters that can confer drug resistance to cancers and pathogens. Furthermore, some ABC transporters are recognised to be involved in conferral of insecticide resistance. While a number of studies have investigated ABC transporters in L. salmonis, no systematic analysis of the ABC gene family exists for this species. This study presents a genome-wide survey of ABC genes in L. salmonis for which, ABC superfamily members were identified through homology searching of the L. salmonis genome. In addition, ABC proteins were identified in a reference transcriptome of the parasite generated by high-throughput RNA sequencing (RNA-seq of a multi-stage RNA library. Searches of both genome and transcriptome allowed the identification of a total of 33 genes / transcripts coding for ABC proteins, of which 3 were represented only in the genome and 4 only in the transcriptome. Eighteen sequences were assigned to ABC subfamilies known to contain drug transporters, i.e. subfamilies B (4 sequences, C (11 and G (2. The results suggest that the ABC gene family of L. salmonis possesses fewer members than recorded for other arthropods. The present survey of the L. salmonis ABC gene superfamily will provide the basis for further research into potential roles of ABC transporters in the toxicity of salmon delousing agents and as potential mechanisms of drug resistance.

  20. A Survey of the ATP-Binding Cassette (ABC) Gene Superfamily in the Salmon Louse (Lepeophtheirus salmonis).

    Science.gov (United States)

    Carmona-Antoñanzas, Greta; Carmichael, Stephen N; Heumann, Jan; Taggart, John B; Gharbi, Karim; Bron, James E; Bekaert, Michaël; Sturm, Armin

    2015-01-01

    Salmon lice, Lepeophtheirus salmonis (Krøyer, 1837), are fish ectoparasites causing significant economic damage in the mariculture of Atlantic salmon, Salmo salar Linnaeus, 1758. The control of L. salmonis at fish farms relies to a large extent on treatment with anti-parasitic drugs. A problem related to chemical control is the potential for development of resistance, which in L. salmonis is documented for a number of drug classes including organophosphates, pyrethroids and avermectins. The ATP-binding cassette (ABC) gene superfamily is found in all biota and includes a range of drug efflux transporters that can confer drug resistance to cancers and pathogens. Furthermore, some ABC transporters are recognised to be involved in conferral of insecticide resistance. While a number of studies have investigated ABC transporters in L. salmonis, no systematic analysis of the ABC gene family exists for this species. This study presents a genome-wide survey of ABC genes in L. salmonis for which, ABC superfamily members were identified through homology searching of the L. salmonis genome. In addition, ABC proteins were identified in a reference transcriptome of the parasite generated by high-throughput RNA sequencing (RNA-seq) of a multi-stage RNA library. Searches of both genome and transcriptome allowed the identification of a total of 33 genes / transcripts coding for ABC proteins, of which 3 were represented only in the genome and 4 only in the transcriptome. Eighteen sequences were assigned to ABC subfamilies known to contain drug transporters, i.e. subfamilies B (4 sequences), C (11) and G (2). The results suggest that the ABC gene family of L. salmonis possesses fewer members than recorded for other arthropods. The present survey of the L. salmonis ABC gene superfamily will provide the basis for further research into potential roles of ABC transporters in the toxicity of salmon delousing agents and as potential mechanisms of drug resistance.

  1. ATP-binding Cassette (ABC) Transport System Solute-binding Protein-guided Identification of Novel d-Altritol and Galactitol Catabolic Pathways in Agrobacterium tumefaciens C58.

    Science.gov (United States)

    Wichelecki, Daniel J; Vetting, Matthew W; Chou, Liyushang; Al-Obaidi, Nawar; Bouvier, Jason T; Almo, Steven C; Gerlt, John A

    2015-11-27

    Innovations in the discovery of the functions of uncharacterized proteins/enzymes have become increasingly important as advances in sequencing technology flood protein databases with an exponentially growing number of open reading frames. This study documents one such innovation developed by the Enzyme Function Initiative (EFI; U54GM093342), the use of solute-binding proteins for transport systems to identify novel metabolic pathways. In a previous study, this strategy was applied to the tripartite ATP-independent periplasmic transporters. Here, we apply this strategy to the ATP-binding cassette transporters and report the discovery of novel catabolic pathways for d-altritol and galactitol in Agrobacterium tumefaciens C58. These efforts resulted in the description of three novel enzymatic reactions as follows: 1) oxidation of d-altritol to d-tagatose via a dehydrogenase in Pfam family PF00107, a previously unknown reaction; 2) phosphorylation of d-tagatose to d-tagatose 6-phosphate via a kinase in Pfam family PF00294, a previously orphan EC number; and 3) epimerization of d-tagatose 6-phosphate C-4 to d-fructose 6-phosphate via a member of Pfam family PF08013, another previously unknown reaction. The epimerization reaction catalyzed by a member of PF08013 is especially noteworthy, because the functions of members of PF08013 have been unknown. These discoveries were assisted by the following two synergistic bioinformatics web tools made available by the Enzyme Function Initiative: the EFI-Enzyme Similarity Tool and the EFI-Genome Neighborhood Tool. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. ATP-binding Cassette (ABC) Transport System Solute-binding Protein-guided Identification of Novel d-Altritol and Galactitol Catabolic Pathways in Agrobacterium tumefaciens C58*

    Science.gov (United States)

    Wichelecki, Daniel J.; Vetting, Matthew W.; Chou, Liyushang; Al-Obaidi, Nawar; Bouvier, Jason T.; Almo, Steven C.; Gerlt, John A.

    2015-01-01

    Innovations in the discovery of the functions of uncharacterized proteins/enzymes have become increasingly important as advances in sequencing technology flood protein databases with an exponentially growing number of open reading frames. This study documents one such innovation developed by the Enzyme Function Initiative (EFI; U54GM093342), the use of solute-binding proteins for transport systems to identify novel metabolic pathways. In a previous study, this strategy was applied to the tripartite ATP-independent periplasmic transporters. Here, we apply this strategy to the ATP-binding cassette transporters and report the discovery of novel catabolic pathways for d-altritol and galactitol in Agrobacterium tumefaciens C58. These efforts resulted in the description of three novel enzymatic reactions as follows: 1) oxidation of d-altritol to d-tagatose via a dehydrogenase in Pfam family PF00107, a previously unknown reaction; 2) phosphorylation of d-tagatose to d-tagatose 6-phosphate via a kinase in Pfam family PF00294, a previously orphan EC number; and 3) epimerization of d-tagatose 6-phosphate C-4 to d-fructose 6-phosphate via a member of Pfam family PF08013, another previously unknown reaction. The epimerization reaction catalyzed by a member of PF08013 is especially noteworthy, because the functions of members of PF08013 have been unknown. These discoveries were assisted by the following two synergistic bioinformatics web tools made available by the Enzyme Function Initiative: the EFI-Enzyme Similarity Tool and the EFI-Genome Neighborhood Tool. PMID:26472925

  3. The Role of ABC Proteins in Drug Resistant Breast Cancer Cells

    National Research Council Canada - National Science Library

    Lekostaj, Jacqueline K

    2008-01-01

    ...) of the Office of the Congressionally Directed Medical Research Programs (CDMRP), aims to study the possible role of ABC transporters in pleitropic drug resistance, using a combination of molecular biological, biochemical, and biophysical methods...

  4. Pentobarbital inhibits glucose uptake, but not water transport by glucose transporter type 3.

    Science.gov (United States)

    Tomioka, Shigemasa; Kaneko, Miyuki; Nakajo, Nobuyoshi

    2012-08-01

    To understand the mechanisms underlying the neuroprotective efficacy of barbiturates, the effect of pentobarbital on glucose uptake and water transport was determined in Xenopus oocytes expressing glucose transporter type 3 (GLUT3). Pentobarbital induced a 50% concentration-dependent inhibition in glucose uptake, but exerted no effect on water transport by GLUT3. Eadie-Hofstee analysis showed that pentobarbital decreased Vmax significantly, but not Km of GLUT3 for 2-deoxy-D-glucose. Although the protein kinase C (PKC) activator significantly decreased glucose uptake by GLUT3, no additive or synergistic interactions were observed between the PKC activator and pentobarbital. Our results suggest that pentobarbital may play an important role in neuroprotection by inhibition of glucose uptake by GLUT3 by a mechanism involving PKC.

  5. Resistance to Bacillus thuringiensis Mediated by an ABC Transporter Mutation Increases Susceptibility to Toxins from Other Bacteria in an Invasive Insect

    Science.gov (United States)

    Zhang, Dandan; Gong, Lingling; He, Fei; Soberón, Mario; Bravo, Alejandra; Tabashnik, Bruce E.; Wu, Kongming

    2016-01-01

    Evolution of pest resistance reduces the efficacy of insecticidal proteins from the gram-positive bacterium Bacillus thuringiensis (Bt) used widely in sprays and transgenic crops. Recent efforts to delay pest adaptation to Bt crops focus primarily on combinations of two or more Bt toxins that kill the same pest, but this approach is often compromised because resistance to one Bt toxin causes cross-resistance to others. Thus, integration of Bt toxins with alternative controls that do not exhibit such cross-resistance is urgently needed. The ideal scenario of negative cross-resistance, where selection for resistance to a Bt toxin increases susceptibility to alternative controls, has been elusive. Here we discovered that selection of the global crop pest, Helicoverpa armigera, for >1000-fold resistance to Bt toxin Cry1Ac increased susceptibility to abamectin and spineotram, insecticides derived from the soil bacteria Streptomyces avermitilis and Saccharopolyspora spinosa, respectively. Resistance to Cry1Ac did not affect susceptibility to the cyclodiene, organophospate, or pyrethroid insecticides tested. Whereas previous work demonstrated that the resistance to Cry1Ac in the strain analyzed here is conferred by a mutation disrupting an ATP-binding cassette protein named ABCC2, the new results show that increased susceptibility to abamectin is genetically linked with the same mutation. Moreover, RNAi silencing of HaABCC2 not only decreased susceptibility to Cry1Ac, it also increased susceptibility to abamectin. The mutation disrupting ABCC2 reduced removal of abamectin in live larvae and in transfected Hi5 cells. The results imply that negative cross-resistance occurs because the wild type ABCC2 protein plays a key role in conferring susceptibility to Cry1Ac and in decreasing susceptibility to abamectin. The negative cross-resistance between a Bt toxin and other bacterial insecticides reported here may facilitate more sustainable pest control. PMID:26872031

  6. The ABCs of particle physics

    CERN Document Server

    Biron, Lauren

    2016-01-01

    For lovers of rhymes and anthropomorphic Higgs bosons, Symmetry presents its first published board book, The ABCs of Particle Physics. Use it as an illustrated guide to basic particle- and astrophysics terms, or read it to your infant at bedtime, if you don’t mind their first word being “quark.”

  7. Preconceptual ABC design definition and system configuration layout

    International Nuclear Information System (INIS)

    Barthold, W.

    1995-03-01

    This document is the conceptual design document for the follow-on to the Molten Salt Breeder Reactor, known as the ABC type reactor. It addresses blanket design options, containment options, off-gas systems, drainage systems, and components/layouts of the primary, secondary, and tertiary systems, and it contains a number of diagrams for the configuration of the major systems

  8. abc: An Extensible AspectJ Compiler

    DEFF Research Database (Denmark)

    Avgustinov, Pavel; Christensen, Aske Simon; Hendren, Laurie J.

    2006-01-01

    Research in the design of aspect-oriented programming languages requires a workbench that facilitates easy experimentation with new language features and implementation techniques. In particular, new features for AspectJ have been proposed that require extensions in many dimensions: syntax, type ...... design decisions. Finally, we review a few examples of projects by others that extend abc in interesting ways...

  9. [Glucose transporter protein type 1 (GLUT-1) deficiency syndrome].

    Science.gov (United States)

    Ramm-Pettersen, Anette; Selmer, Kaja Kristine; Nakken, Karl O

    2011-05-06

    Glucose is the brain's main source of energy. To pass the blood-brain barrier, glucose transporter protein type 1 (GLUT-1) is essential. Mutations in the SLC2A1 gene which codes for GLUT-1 may therefore compromise the supply of glucose to the brain. The aim of this review is to describe the clinical consequences of such mutations, with special emphasis on GLUT-1 encephalopathy. This review is based on a non-systematic literature search in PubMed and the authors' experience within the field. Epileptic or epilepsy-like are usually the first symptom in children with the GLUT-1 deficiency syndrome. Later on these children suffer delayed psychomotor development, microcephaly, ataxia, spasticity or movement disorders. EEG abnormalities may develop. GLUT-1 deficiency syndrome should be suspected in children with epilepsy-like seizures and delayed development combined with a low content of glucose in spinal fluid. The diagnosis is confirmed by genetic testing. Treatment is a ketogenic diet, as ketone bodies pass the blood-brain barrier using other transport proteins than GLUT-1. GLUT-1-deficiency syndrome is a rare metabolic encephalopathy which is not well known and probably underdiagnosed. An early diagnosis and early start of a ketogenic diet may give these children a normal or nearly normal life.

  10. Wireless technology for ABC Assessment

    DEFF Research Database (Denmark)

    Kristensen, Margit; Kyng, Morten; Christensen, Erika Frischknecht

    be just beside a victim to assess the ABC status. Consequently - in situations with many victims - monitoring equipment is only used for the (few) most seriously injured. Our ongoing research builds on data collected through extensive field studies and is described in several published papers. We......  In medical emergency service (EMS) the ABC status (Airway-Breathing-Circulation) of victims is essential in the decision making process regarding prioritizing and treatment. Today's use of information technology does, however, not inform directly about "A" and "B". The parameters are evaluated...... indirectly through assessment of collected biosensor data, such as ECG, and directly by the rescuer regarding how the patient looks and sounds. Moreover, the monitoring equipment used today is connected with displays by wires and thus only utilizes one display at a time. This means that the rescuers must...

  11. INVENTORY CLASSIFICATION WITH ABC ANALYSIS

    OpenAIRE

    Kıyak, Erkan; Timuş, Oğuz Han; Karayel, Mehmet

    2015-01-01

    For a substantial organization, managing the expansive inventory is a serious problem. One of the methods to solve this problem used widely is classifying the inventory according to some criteria and managing inventory according to this classisifation. In this study, ABC classification methods are researched and Ng's model, which is one of the most widely used, selected for further investigation. An illustrative example is presented to show the usability of the Ng's method.

  12. Study of Statewide Type II Noise Abatement Program for the Texas Department of Transportation

    Science.gov (United States)

    2000-02-01

    This project will provide sufficient information to the Texas Department of Transportation and the Texas Transportation Commission to make an informed decision regarding the development and implementation of a statewide Type II Noise Abatement Progra...

  13. An inventory of the human ABC proteins.

    Science.gov (United States)

    Klein, I; Sarkadi, B; Váradi, A

    1999-12-06

    Currently 30 human ABC proteins are represented by full sequences in various databases, and this paper provides a brief overview of these proteins. ABC proteins are composed of transmembrane domains (TMDs), and nucleotide binding domains (NBDs, or ATP-binding cassettes, ABSs). The arrangement of these domains, together with available membrane topology models of the family members, are presented. Based on their sequence similarity scores, the members of the human ABC protein family can be grouped into eight subfamilies. At present the MDR/TAP, the ALD, the MRP/CFTR, the ABC1, the White, the RNAseL inhibitor, the ANSA, and the GCN20 subfamilies are identified. Mutations of many human ABC proteins are known to be causative in inherited diseases, and a short description of the molecular pathology of these ABC gene-related genetic diseases is also provided.

  14. Transport Properties Of Type-I Sn Clathrates

    Science.gov (United States)

    Egbele, Peter; Joubert, Daniel; Shoko, Elvis

    The conversion of 'waste' heat into useful energy can contribute to the efficient use of available energy. This includes converting heat energy from internal combustion engines, conventional power plants and solar cells into usable energy. Thermoelectric devices can convert heat into an electric current and have immense potential for utilizing heat energy. One of the desired features of an efficient thermoelectric material is a low lattice thermal conductivity. In this study thermal transport properties of type-I Sn clathrates are investigated. We study the dynamics of the guest atoms Cs and K in the compound A8 Sn44 (A = Cs, K). We find that the guest atom are responsible for scattering of the heat in these systems, and hence responsible for the low thermal conductivity in these materials. These compounds are formed in a cubic lattice. A low thermal conductivity value of 0.17 and 0.18 W m-1 K-1 at 300 K respectively, was calculated for Cs8 Sn44 and K8 Sn44 . These are low values which makes these and similar materials attractive for further study. NRF South Africa.

  15. Steviol Glycosides Modulate Glucose Transport in Different Cell Types

    Science.gov (United States)

    Rizzo, Benedetta; Zambonin, Laura; Leoncini, Emanuela; Vieceli Dalla Sega, Francesco; Prata, Cecilia; Fiorentini, Diana; Hrelia, Silvana

    2013-01-01

    Extracts from Stevia rebaudiana Bertoni, a plant native to Central and South America, have been used as a sweetener since ancient times. Currently, Stevia extracts are largely used as a noncaloric high-potency biosweetener alternative to sugar, due to the growing incidence of type 2 diabetes mellitus, obesity, and metabolic disorders worldwide. Despite the large number of studies on Stevia and steviol glycosides in vivo, little is reported concerning the cellular and molecular mechanisms underpinning the beneficial effects on human health. The effect of four commercial Stevia extracts on glucose transport activity was evaluated in HL-60 human leukaemia and in SH-SY5Y human neuroblastoma cells. The extracts were able to enhance glucose uptake in both cellular lines, as efficiently as insulin. Our data suggest that steviol glycosides could act by modulating GLUT translocation through the PI3K/Akt pathway since treatments with both insulin and Stevia extracts increased the phosphorylation of PI3K and Akt. Furthermore, Stevia extracts were able to revert the effect of the reduction of glucose uptake caused by methylglyoxal, an inhibitor of the insulin receptor/PI3K/Akt pathway. These results corroborate the hypothesis that Stevia extracts could mimic insulin effects modulating PI3K/Akt pathway. PMID:24327825

  16. Maltose-binding protein effectively stabilizes the partially closed conformation of the ATP-binding cassette transporter MalFGK2

    KAUST Repository

    Weng, Jingwei

    2017-02-23

    Maltose transporter MalFGK2 is a type-I importer in the ATP-binding cassette (ABC) transporter superfamily. Upon the binding of its periplasmic binding protein, MalE, the ATPase activity of MalFGK2 can be greatly enhanced. Crystal structures of the MalFGK2-MalE-maltose complex in a so-called

  17. Enterprise Architecture Data Pada Hotel ABC

    OpenAIRE

    Soesatyo, Stephanie; Wibowo, Adi; Handojo, Andreas

    2015-01-01

    Hotel ABC is a company engaged in hospitality management, i.e. room rental, rental of meeting rooms and coffee shop. Hotel ABC has a branch that has the same specifications of the hotel. In business process, Hotel ABC has information systems to support existing business processes. However, existing information systems have not been integrated as a whole. Based on the condition stated above, analysis and design of enterprise architecture information system is created for the company. The proce...

  18. Structural and functional diversity of substrate-binding domains in ABC importers

    NARCIS (Netherlands)

    Fulyani, Faizah

    2015-01-01

    In dit proefschrift heb ik de structuur en functie van GlnPQ, een ATP- bindingscassette (ABC) transporter, bepaald. GlnPQ heeft twee verschillende, met elkaar verbonden substraatbindende domeinen (SBDs), die aan het transmembraan domein van de transporter vast zitten. Ondanks het feit dat de

  19. Learning the ABCs: Activity based costing in waste operations

    International Nuclear Information System (INIS)

    Zocher, Marc A.

    1992-01-01

    The United States Department of Energy (DOE) is facing a challenging new national role based on current world events, changing public perception and awareness, and a legacy of wastes generated in the past. Clearly, the DOE must put mechanisms in place to comply with environmental rules, regulations, and good management practices so that public health risk is minimized while programmatic costs are controlled. DOE has begun this process and has developed a Five-Year Plan to describe the activities necessary to comply with both cleanup, or environmental restoration, and waste management of existing waste streams. The focus of this paper is how to best manage the treatment, storage, disposal, and transportation of waste throughout the DOE weapons complex by using Activity Based Costing (ABC) to both plan and control expenditures in DOE Waste Management (WM). The basics of ABC, along with an example, will be detailed. (author)

  20. Transport studies in p-type double quantum well samples

    International Nuclear Information System (INIS)

    Hyndman, R.J.

    2000-01-01

    The motivation for the study of double quantum well samples is that the extra spatial degree of freedom can modify the ground state energies of the system, leading to new and interesting many body effects. Electron bi-layers have been widely studied but the work presented here is the first systematic study of transport properties of a p-type, double quantum well system. The samples, grown on the 311 plane, consisted of two 100A GaAs wells separated by a 30A AlAs barrier. The thin barrier in our structures, gives rise to very strong inter-layer Coulombic interactions but in contrast to electron double quantum well samples, tunnelling between the two wells is very weak. This is due to the large effective mass of holes compared with electrons. It is possible to accurately control the total density of a sample and the relative occupancy of each well using front and back gates. A systematic study of the magnetoresistance properties of the p-type bi-layers, was carried out at low temperatures and in high magnetic fields, for samples covering a range of densities. Considerable care was required to obtain reliable results as the samples were extremely susceptible to electrical shock and were prone to drift in density slowly over time. With balanced wells, the very low tunnelling in the p-type bi-layer leads to a complete absence of all odd integers in both resistance and thermopower except for the v=1 state, ( v 1/2 in each layer) where v is the total Landau level filling factor. Unlike other FQHE features the v=1 state strengthens with increased density as inter-layer interactions increase in strength over intra-layer interactions. The state is also destroyed at a critical temperature, which is much lower than the measured activation temperature. This is taken as evidence for a finite temperature phase transition predicted for the bi-layer v=1. From the experimental observations, we construct a phase diagram for the state, which agree closely with theoretical predictions

  1. Playware ABC: Engineering Play for Everybody

    DEFF Research Database (Denmark)

    Lund, Henrik Hautop

    2017-01-01

    This paper describes the Playware ABC concept, and how it allows anybody, anywhere, anytime to be building bodies and brains, which facilitates users to construct, combine and create. The Playware ABC concept focuses engineering and IT system development on creating solutions that are usable by a...

  2. ABC classification : service levels and inventory costs

    NARCIS (Netherlands)

    Teunter, R.H.; Babai, M.; Syntetos, A.

    2010-01-01

    ABC inventory classifications are widely used in practice, with demand value and demand volume as the most common ranking criteria. The standard approach in ABC applications is to set the same service level for all stock keeping units (SKUs) in a class. In this paper, we show (for three large real

  3. Structural and Thermal Safety Analysis Report for the Type B Radioactive Waste Transport Package

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. H.; Seo, K. S.; Lee, J. C.; Bang, K. S

    2007-09-15

    We carried out structural safety evaluation for the type B radioactive waste transport package. Requirements for type B packages according to the related regulations such as IAEA Safety Standard Series No. TS-R-1, Korea Most Act. 2001-23 and US 10 CFR Part 71 were evaluated. General requirements for packages such as those for a lifting attachment, a tie-down attachment and pressure condition were considered. For the type B radioactive waste transport package, the structural, thermal and containment analyses were carried out under the normal transport conditions. Also the safety analysis were conducted under the accidental transport conditions. The 9 m drop test, 1 m puncture test, fire test and water immersion test under the accidental transport conditions were consecutively done. The type B radioactive waste transport packages were maintained the structural and thermal integrities.

  4. A common highly conserved cadmium detoxification mechanism from bacteria to humans: heavy metal tolerance conferred by the ATP-binding cassette (ABC) transporter SpHMT1 requires glutathione but not metal-chelating phytochelatin peptides.

    Science.gov (United States)

    Prévéral, Sandra; Gayet, Landry; Moldes, Cristina; Hoffmann, Jonathan; Mounicou, Sandra; Gruet, Antoine; Reynaud, Florie; Lobinski, Ryszard; Verbavatz, Jean-Marc; Vavasseur, Alain; Forestier, Cyrille

    2009-02-20

    Cadmium poses a significant threat to human health due to its toxicity. In mammals and in bakers' yeast, cadmium is detoxified by ATP-binding cassette transporters after conjugation to glutathione. In fission yeast, phytochelatins constitute the co-substrate with cadmium for the transporter SpHMT1. In plants, a detoxification mechanism similar to the one in fission yeast is supposed, but the molecular nature of the transporter is still lacking. To investigate further the relationship between SpHMT1 and its co-substrate, we overexpressed the transporter in a Schizosaccharomyces pombe strain deleted for the phytochelatin synthase gene and heterologously in Saccharomyces cerevisiae and in Escherichia coli. In all organisms, overexpression of SpHMT1 conferred a markedly enhanced tolerance to cadmium but not to Sb(III), AgNO(3), As(III), As(V), CuSO(4), or HgCl(2). Abolishment of the catalytic activity by expression of SpHMT1(K623M) mutant suppressed the cadmium tolerance phenotype independently of the presence of phytochelatins. Depletion of the glutathione pool inhibited the SpHMT1 activity but not that of AtHMA4, a P-type ATPase, indicating that GSH is necessary for the SpHMT1-mediated cadmium resistance. In E. coli, SpHMT1 was targeted to the periplasmic membrane and led to an increased amount of cadmium in the periplasm. These results demonstrate that SpHMT1 confers cadmium tolerance in the absence of phytochelatins but depending on the presence of GSH and ATP. Our results challenge the dogma of the two separate cadmium detoxification pathways and demonstrate that a common highly conserved mechanism has been selected during the evolution from bacteria to humans.

  5. Membrane Anchoring and Ion-Entry Dynamics in P-type ATPase Copper Transport

    DEFF Research Database (Denmark)

    Grønberg, Christina; Sitsel, Oleg; Lindahl, Erik

    2016-01-01

    Cu(+)-specific P-type ATPase membrane protein transporters regulate cellular copper levels. The lack of crystal structures in Cu(+)-binding states has limited our understanding of how ion entry and binding are achieved. Here, we characterize the molecular basis of Cu(+) entry using molecular...... and provide a molecular understanding of ion entry in Cu(+)-transporting P-type ATPases....

  6. ATP-binding cassette (ABC) proteins in aquatic invertebrates: Evolutionary significance and application in marine ecotoxicology.

    Science.gov (United States)

    Jeong, Chang-Bum; Kim, Hui-Su; Kang, Hye-Min; Lee, Jae-Seong

    2017-04-01

    The ATP-binding cassette (ABC) protein superfamily is known to play a fundamental role in biological processes and is highly conserved across animal taxa. The ABC proteins function as active transporters for multiple substrates across the cellular membrane by ATP hydrolysis. As this superfamily is derived from a common ancestor, ABC genes have evolved via lineage-specific duplications through the process of adaptation. In this review, we summarized information about the ABC gene families in aquatic invertebrates, considering their evolution and putative functions in defense mechanisms. Phylogenetic analysis was conducted to examine the evolutionary significance of ABC gene families in aquatic invertebrates. Particularly, a massive expansion of multixenobiotic resistance (MXR)-mediated efflux transporters was identified in the absence of the ABCG2 (BCRP) gene in Ecdysozoa and Platyzoa, suggesting that a loss of Abcg2 gene occurred sporadically in these species during divergence of Protostome to Lophotrochozoa. Furthermore, in aquatic invertebrates, the ecotoxicological significance of MXR is discussed while considering the role of MXR-mediated efflux transporters in response to various environmental pollutants. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Lactate/H+ transport kinetics in rat skeletal muscle related to fibre type and changes in transport capacity

    DEFF Research Database (Denmark)

    Juel; Pilegaard

    1998-01-01

    and hypothyroidism was due to a decrease in Vmax. The denervation-induced decline in lactate/H+ transport capacity resulted from both an increased Km and a reduced Vmax. The present data show that muscle type differences and most changes in the lactate/H+ transport capacity are mediated by modifications in Vmax......Lactate/H+ transport kinetics were determined by means of the pH-sensitive probe BCECF in sarcolemmal giant vesicles, obtained from rat skeletal muscle, and related to variations in lactate/H+ transport capacity. Vesicle preparations were made from red and white muscles, mixed muscles, denervated...... muscles, muscles of old rats and rats that had been subjected to high-intensity training, endurance training, repeated exposure to hypoxia, and hypothyroid or hyperthyroid treatments. The lactate/H+ transport capacity of red muscles was greater than that of white muscles, and this difference...

  8. Lactate/H+ transport kinetics in rat skeletal muscle related to fibre type and changes in transport capacity

    DEFF Research Database (Denmark)

    Juel; Pilegaard

    1998-01-01

    muscles, muscles of old rats and rats that had been subjected to high-intensity training, endurance training, repeated exposure to hypoxia, and hypothyroid or hyperthyroid treatments. The lactate/H+ transport capacity of red muscles was greater than that of white muscles, and this difference......Lactate/H+ transport kinetics were determined by means of the pH-sensitive probe BCECF in sarcolemmal giant vesicles, obtained from rat skeletal muscle, and related to variations in lactate/H+ transport capacity. Vesicle preparations were made from red and white muscles, mixed muscles, denervated...... and hypothyroidism was due to a decrease in Vmax. The denervation-induced decline in lactate/H+ transport capacity resulted from both an increased Km and a reduced Vmax. The present data show that muscle type differences and most changes in the lactate/H+ transport capacity are mediated by modifications in Vmax...

  9. Inventory and general analysis of the ATP-binding cassette (ABC) gene superfamily in maize (Zea mays L.).

    Science.gov (United States)

    Pang, Kaiyuan; Li, Yanjiao; Liu, Menghan; Meng, Zhaodong; Yu, Yanli

    2013-09-10

    The metabolic functions of ATP-binding cassette (or ABC) proteins, one of the largest families of proteins presented in all organisms, have been investigated in many protozoan, animal and plant species. To facilitate more systematic and complicated studies on maize ABC proteins in the future, we present the first complete inventory of these proteins, including 130 open reading frames (ORFs), and provide general descriptions of their classifications, basic structures, typical functions, evolution track analysis and expression profiles. The 130 ORFs were assigned to eight subfamilies based on their structures and homological features. Five of these subfamilies consist of 109 proteins, containing transmembrane domains (TM) performing as transporters. The rest three subfamilies contain 21 soluble proteins involved in various functions other than molecular transport. A comparison of ABC proteins among nine selected species revealed either convergence or divergence in each of the ABC subfamilies. Generally, plant genomes contain far more ABC genes than animal genomes. The expression profiles and evolution track of each maize ABC gene were further investigated, the results of which could provide clues for analyzing their functions. Quantitative real-time polymerase chain reaction experiments (PCR) were conducted to detect induced expression in select ABC genes under several common stresses. This investigation provides valuable information for future research on stress tolerance in plants and potential strategies for enhancing maize production under stressful conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. ABCB1 and ABCC1-like transporters in immune system cells from sea urchins Echinometra lucunter and Echinus esculentus and oysters Crassostrea gasar and Crassostrea gigas.

    Science.gov (United States)

    Marques-Santos, Luis Fernando; Hégaret, Hélène; Lima-Santos, Leonardo; Queiroga, Fernando Ramos; da Silva, Patricia Mirella

    2017-11-01

    ABC transporters activity and expression have been associated with the multixenobiotic resistance phenotype (MXR). The activity of these proteins leads to a reduction in the intracellular concentration of several xenobiotics, thus reducing their toxicity. However, little attention has been given to the expression of ABC transporters in marine invertebrates and few studies have investigated their role in immune system cells of sea urchins and shellfish bivalves. The aim of the present study was to investigate the activity of the ABC transporters ABCB1 and ABCC1 in immune system cells of sea urchins (coelomocytes) and oysters (hemocytes) from different climatic regions (Brazil and France). Sea urchins and oysters were collected at Paraíba coast; Brazil (Echinometra lucunter and Crassostrea gasar) and Rade of Brest; France (Echinus esculentus and Crassostrea gigas). Coelomocytes and hemocytes were stained with the ABC transporter substrate calcein-AM and dye accumulation analyzed under flow cytometry. Reversin 205 (ABCB1 transporter blocker) and MK571 (ABCC1 transporter blocker) were used as pharmacological tools to investigate ABC transporter activity. A different pattern of calcein accumulation was observed in coelomocytes: phagocytes > colorless spherulocytes > vibrate cells > red spherulocytes. The treatment with MK571 increased calcein fluorescence levels in coelomocytes from both species. However, reversin 205 treatment was not able to increase calcein fluorescence in E. esculentus coelomocytes. These data suggest that ABCC1-like transporter activity is present in both sea urchin species, but ABCB1-like transporter activity might only be present in E. lucunter coelomocytes. The activity of ABCC1-like transporter was observed in all cell types from both bivalve species. However, reversin 205 only increased calcein accumulation in hyalinocytes of the oyster C. gasar, suggesting the absence of ABCB1-like transporter activity in all other cell types

  11. An ABC for decision making

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Luiz Henrique Costa, E-mail: luiz_mogi@yahoo.com.br [Associacao de Medicina Intensiva Brasileira (AMIB), Sao Paulo, SP (Brazil); Irmandade da Santa Casa de Misericordia de Sao Paulo, SP (Brazil); Ferreira, Bruna Cortez [Hospital de Base de Sao Jose do Rio Preto, SP (Brazil)

    2015-03-15

    The present study was aimed at proposing a systematic evaluation of cranial computed tomography, identifying the main aspects to be analyzed in order to facilitate the decision making process regarding diagnosis and management in emergency settings. The present descriptive study comprised a literature review at the following databases: Access Medicine and Access Emergency Medicine (McGraw-Hill Education); British Medical Journal Evidence Center; UptoDate; Bireme; PubMed; Lilacs; SciELO; ProQuest; Micromedex (Thomson Reuters); Embase. Once the literature review was completed, the authors identified the main diseases with tomographic repercussions and proposed the present system to evaluate cranial computed tomography images. An easy-to-memorize ABC system will facilitate the decision making in emergency settings, as it covers the main diseases encountered by intensivists and emergency physicians, and provides a sequential guidance about anatomical structures to be investigated as well as their respective alterations. (author)

  12. An ABC for decision making

    International Nuclear Information System (INIS)

    Garcia, Luiz Henrique Costa; Ferreira, Bruna Cortez

    2015-01-01

    The present study was aimed at proposing a systematic evaluation of cranial computed tomography, identifying the main aspects to be analyzed in order to facilitate the decision making process regarding diagnosis and management in emergency settings. The present descriptive study comprised a literature review at the following databases: Access Medicine and Access Emergency Medicine (McGraw-Hill Education); British Medical Journal Evidence Center; UptoDate; Bireme; PubMed; Lilacs; SciELO; ProQuest; Micromedex (Thomson Reuters); Embase. Once the literature review was completed, the authors identified the main diseases with tomographic repercussions and proposed the present system to evaluate cranial computed tomography images. An easy-to-memorize ABC system will facilitate the decision making in emergency settings, as it covers the main diseases encountered by intensivists and emergency physicians, and provides a sequential guidance about anatomical structures to be investigated as well as their respective alterations. (author)

  13. An ABC for decision making

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Costa Garcia

    2015-04-01

    Full Text Available The present study was aimed at proposing a systematic evaluation of cranial computed tomography, identifying the main aspects to be analyzed in order to facilitate the decision making process regarding diagnosis and management in emergency settings. The present descriptive study comprised a literature review at the following databases: Access Medicine and Access Emergency Medicine (McGraw- Hill Education; British Medical Journal Evidence Center; UptoDate; Bireme; PubMed; Lilacs; SciELO; ProQuest; Micromedex (Thomson Reuters; Embase. Once the literature review was completed, the authors identified the main diseases with tomographic repercussions and proposed the present system to evaluate cranial computed tomography images. An easy-to-memorize ABC system will facilitate the decision making in emergency settings, as it covers the main diseases encountered by intensivists and emergency physicians, and provides a sequential guidance about anatomical structures to be investigated as well as their respective alterations.

  14. Sodium-glucose co-transporter type 2 inhibitors reduce evening home blood pressure in type 2 diabetes with nephropathy.

    Science.gov (United States)

    Takenaka, Tsuneo; Kishimoto, Miyako; Ohta, Mari; Tomonaga, Osamu; Suzuki, Hiromichi

    2017-05-01

    The effects of sodium-glucose co-transporter type 2 inhibitors on home blood pressure were examined in type 2 diabetes with nephropathy. The patients with diabetic nephropathy were screened from medical records in our hospitals. Among them, 52 patients who measured home blood pressure and started to take sodium-glucose co-transporter type 2 inhibitors were selected. Clinical parameters including estimated glomerular filtration rate, albuminuria and home blood pressure for 6 months were analysed. Sodium-glucose co-transporter type 2 inhibitors (luseogliflozin 5 mg/day or canagliflozin 100 mg/day) reduced body weight, HbA1c, albuminuria, estimated glomerular filtration rate and office blood pressure. Although sodium-glucose co-transporter type 2 inhibitors did not alter morning blood pressure, it reduced evening systolic blood pressure. Regression analyses revealed that decreases in evening blood pressure predicted decrements in albuminuria. The present data suggest that sodium-glucose co-transporter type 2 inhibitors suppress sodium overload during daytime to reduce evening blood pressure and albuminuria.

  15. Arnold Diffusion of Charged Particles in ABC Magnetic Fields

    Science.gov (United States)

    Luque, Alejandro; Peralta-Salas, Daniel

    2017-06-01

    We prove the existence of diffusing solutions in the motion of a charged particle in the presence of ABC magnetic fields. The equations of motion are modeled by a 3DOF Hamiltonian system depending on two parameters. For small values of these parameters, we obtain a normally hyperbolic invariant manifold and we apply the so-called geometric methods for a priori unstable systems developed by A. Delshams, R. de la Llave and T.M. Seara. We characterize explicitly sufficient conditions for the existence of a transition chain of invariant tori having heteroclinic connections, thus obtaining global instability (Arnold diffusion). We also check the obtained conditions in a computer-assisted proof. ABC magnetic fields are the simplest force-free-type solutions of the magnetohydrodynamics equations with periodic boundary conditions, and can be considered as an elementary model for the motion of plasma-charged particles in a tokamak.

  16. Sucrose transporters in two members of the Scrophulariaceae with different types of transport sugar.

    Science.gov (United States)

    Knop, C; Voitsekhovskaja, O; Lohaus, G

    2001-05-01

    In order to study differences between sugar transport in oligosaccharide-translocating and sucrose-translocating species, two members of the Scrophulariaceae, Asarina barclaiana Pennell and Alonsoa meridionalis O. Kuntze, were analysed regarding minor-vein anatomy, sugar concentrations in leaves and phloem sap, and expression of sucrose transporters. The minor veins of Asarina barclaiana possess mainly transfer cells and modified intermediary cells and those of Alonsoa meridionalis have intermediary cells and ordinary companion cells. Phloem sap from these plants was collected by the laser-aphid-stylet technique. The main carbon transport forms in Asarina were sucrose and in Alonsoa raffinose and stachyose. The sum of the carbohydrate concentrations in the phloem sap of both species was as high as that in apoplastic phloem loaders. In Asarina the ratio of the sucrose concentration in the phloem to that in the cytosol of source cells was about 35 and the corresponding ratio in Alonsoa was about two. Sucrose transporter cDNAs were isolated from leaves of both species. By means of semi-quantitative reverse transcription-polymerase chain reaction, sucrose transporter mRNA was detected in different organs and also in the phloem sap. This is the first time that sucrose transporters have been found in oligosaccharide-translocating species and that the mRNA of these sucrose transporters has been localized directly in the phloem sap. Taken together, our observations indicate that Asarina is an apoplastic phloem loader, while the results for Alonsoa are ambiguous: some properties are typical of the symplastic phloem-loading mechanism, but probably a sucrose transporter is involved in loading and/or retrieval of sucrose into the phloem.

  17. ATP Binding Cassette Transporter Mediates Both Heme and Pesticide Detoxification in Tick Midgut Cells.

    Directory of Open Access Journals (Sweden)

    Flavio Alves Lara

    Full Text Available In ticks, the digestion of blood occurs intracellularly and proteolytic digestion of hemoglobin takes place in a dedicated type of lysosome, the digest vesicle, followed by transfer of the heme moiety of hemoglobin to a specialized organelle that accumulates large heme aggregates, called hemosomes. In the present work, we studied the uptake of fluorescent metalloporphyrins, used as heme analogs, and amitraz, one of the most regularly used acaricides to control cattle tick infestations, by Rhipicephalus (Boophilus microplus midgut cells. Both compounds were taken up by midgut cells in vitro and accumulated inside the hemosomes. Transport of both molecules was sensitive to cyclosporine A (CsA, a well-known inhibitor of ATP binding cassette (ABC transporters. Rhodamine 123, a fluorescent probe that is also a recognized ABC substrate, was similarly directed to the hemosome in a CsA-sensitive manner. Using an antibody against conserved domain of PgP-1-type ABC transporter, we were able to immunolocalize PgP-1 in the digest vesicle membranes. Comparison between two R. microplus strains that were resistant and susceptible to amitraz revealed that the resistant strain detoxified both amitraz and Sn-Pp IX more efficiently than the susceptible strain, a process that was also sensitive to CsA. A transcript containing an ABC transporter signature exhibited 2.5-fold increased expression in the amitraz-resistant strain when compared with the susceptible strain. RNAi-induced down-regulation of this ABC transporter led to the accumulation of metalloporphyrin in the digestive vacuole, interrupting heme traffic to the hemosome. This evidence further confirms that this transcript codes for a heme transporter. This is the first report of heme transport in a blood-feeding organism. While the primary physiological function of the hemosome is to detoxify heme and attenuate its toxicity, we suggest that the use of this acaricide detoxification pathway by ticks may

  18. ATP Binding Cassette Transporter Mediates Both Heme and Pesticide Detoxification in Tick Midgut Cells

    Science.gov (United States)

    Lara, Flavio Alves; Pohl, Paula C.; Gandara, Ana Caroline; Ferreira, Jessica da Silva; Nascimento-Silva, Maria Clara; Bechara, Gervásio Henrique; Sorgine, Marcos H. F.; Almeida, Igor C.; Vaz, Itabajara da Silva; Oliveira, Pedro L.

    2015-01-01

    In ticks, the digestion of blood occurs intracellularly and proteolytic digestion of hemoglobin takes place in a dedicated type of lysosome, the digest vesicle, followed by transfer of the heme moiety of hemoglobin to a specialized organelle that accumulates large heme aggregates, called hemosomes. In the present work, we studied the uptake of fluorescent metalloporphyrins, used as heme analogs, and amitraz, one of the most regularly used acaricides to control cattle tick infestations, by Rhipicephalus (Boophilus) microplus midgut cells. Both compounds were taken up by midgut cells in vitro and accumulated inside the hemosomes. Transport of both molecules was sensitive to cyclosporine A (CsA), a well-known inhibitor of ATP binding cassette (ABC) transporters. Rhodamine 123, a fluorescent probe that is also a recognized ABC substrate, was similarly directed to the hemosome in a CsA-sensitive manner. Using an antibody against conserved domain of PgP-1-type ABC transporter, we were able to immunolocalize PgP-1 in the digest vesicle membranes. Comparison between two R. microplus strains that were resistant and susceptible to amitraz revealed that the resistant strain detoxified both amitraz and Sn-Pp IX more efficiently than the susceptible strain, a process that was also sensitive to CsA. A transcript containing an ABC transporter signature exhibited 2.5-fold increased expression in the amitraz-resistant strain when compared with the susceptible strain. RNAi-induced down-regulation of this ABC transporter led to the accumulation of metalloporphyrin in the digestive vacuole, interrupting heme traffic to the hemosome. This evidence further confirms that this transcript codes for a heme transporter. This is the first report of heme transport in a blood-feeding organism. While the primary physiological function of the hemosome is to detoxify heme and attenuate its toxicity, we suggest that the use of this acaricide detoxification pathway by ticks may represent a new

  19. Complete inventory of ABC proteins in human pathogenic yeast, Candida albicans.

    Science.gov (United States)

    Gaur, Manisha; Choudhury, Devapriya; Prasad, Rajendra

    2005-01-01

    The recent completion of the sequencing project of the opportunistic human pathogenic yeast, Candida albicans (http://www.ncbi.nlm.nih.gov/), led us to analyze and classify its ATP-binding cassette (ABC) proteins, which constitute one of the largest superfamilies of proteins. Some of its members are multidrug transporters responsible for the commonly encountered problem of antifungal resistance. TBLASTN searches together with domain analysis identified 81 nucleotide-binding domains, which belong to 51 different putative open reading frames. Considering that each allelic pair represents a single ABC protein of the Candida genome, the total number of putative members of this superfamily is 28. Domain organization, sequence-based analysis and self-organizing map-based clustering led to the classification of Candida ABC proteins into 6 distinct subfamilies. Each subfamily from C. albicans has an equivalent in Saccharomyces cerevisiae suggesting a close evolutionary relationship between the two yeasts. Our searches also led to the identification of a new motif to each subfamily in Candida that could be used to identify sequences from the corresponding subfamily in other organisms. It is hoped that the inventory of Candida ABC transporters thus created will provide new insights into the role of ABC proteins in antifungal resistance as well as help in the functional characterization of the superfamily of these proteins. 2005 S. Karger AG, Basel

  20. Effective removal of a range of Ti/Ri plasmids using a pBBR1-type vector having a repABC operon and a lux reporter system.

    Science.gov (United States)

    Yamamoto, Shinji; Sakai, Ayako; Agustina, Vita; Moriguchi, Kazuki; Suzuki, Katsunori

    2018-02-01

    Ti and Ri plasmids of pathogenic Agrobacterium strains are stably maintained by the function of a repABC operon and have been classified into four incompatibility groups, namely, incRh1, incRh2, incRh3, and incRh4. Removal of these plasmids from their bacterial cells is an important step in determining strain-specific virulence characteristics and to construct strains useful for transformation. Here, we developed two powerful tools to improve this process. We first established a reporter system to detect the presence and absence of Ti/Ri plasmids in cells by using an acetosyringone (AS)-inducible promoter of the Ti2 small RNA and luxAB from Vibrio harveyi. This system distinguished a Ti/Ri plasmid-free cell colony among plasmid-harboring cell colonies by causing the latter colonies to emit light in response to AS. We then constructed new "Ti/Ri eviction plasmids," each of which carries a repABC from one of four Ti/Ri plasmids that belonged to incRh1, incRh2, incRh3, and incRh4 groups in the suicidal plasmid pK18mobsacB and in a broad-host-range pBBR1 vector. Introduction of the new eviction plasmids into Agrobacterium cells harboring the corresponding Ti/Ri plasmids led to Ti/Ri plasmid-free cells in every incRh group. The Ti/Ri eviction was more effective by plasmids with the pBBR1 backbone than by those with the pK18mobsacB backbone. Furthermore, the highly stable cryptic plasmid pAtC58 in A. tumefaciens C58 was effectively evicted by the introduction of a pBBR1 vector containing the repABC of pAtC58. These results indicate that the set of pBBR1-repABC plasmids is a powerful tool for the removal of stable rhizobial plasmids.

  1. Experience of air transport of nuclear fuel material as type A package

    International Nuclear Information System (INIS)

    Kawasaki, Masashi; Kageyama, Tomio; Suzuki, Toru

    2004-01-01

    Special law on nuclear disaster countermeasures (hereafter called as to nuclear disaster countermeasures low) that is domestic law for dealing with measures for nuclear disaster, was enforced in June, 2000. Therefore, nuclear enterprise was obliged to report accidents as required by nuclear disaster countermeasures law, besides meeting the technical requirement of existent transport regulation. For overseas procurement of plutonium reference materials that are needed for material accountability, A Type package must be transported by air. Therefore, concept of air transport of nuclear fuel materials according to the nuclear disaster countermeasures law was discussed, and the manual including measures against accident in air transport was prepared for the oversea procurement. In this presentation, the concept of air transport of A Type package containing nuclear fuel materials according to the nuclear disaster countermeasures law, and the experience of a transportation of plutonium solution from France are shown. (author)

  2. ABCs of Oral Health: Nutrition - Children

    Science.gov (United States)

    ... higher risk for heart attacks More ABCs of Oral Health A | B | C | D | E | F | G | H | ... Children Home | InfoBites | Find a Dentist | Your Family's Oral Health | RSS About AGD | Contact AGD | Site Map | Reprints ...

  3. ABC Inventory classification application: Özdemirler

    OpenAIRE

    Duru, Mehmet

    1989-01-01

    Ankara : The Department of Management and the Institute of Management Sciences of Bilkent Univ. , 1989. Thesis (Master's) -- Bilkent University, 1989. Includes bibliographical references leaves 37. ABC inventory classification can result in more effective control of business. In this work, ABC method is applied to Ozdemirler to examine the inventory profile of the store, and to be able to aid the management in allocating control effort among items more effectively. Dur...

  4. A mathematical model of amphibian skin epithelium with two types of transporting cellular units

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E

    1985-01-01

    A computer model of ion transport across amphibian skin epithelium containing two types of cellular units, their relative number and sizes, and a paracellular pathway has been developed. The two cellular units are, a large Na+ transporting compartment representing the major epithelium from stratum...

  5. Glucose Transporter Type 1 Deficiency Syndrome with Carbohydrate-Responsive Symptoms but without Epilepsy

    Science.gov (United States)

    Koy, Anne; Assmann, Birgit; Klepper, Joerg; Mayatepek, Ertan

    2011-01-01

    Glucose transporter type 1 deficiency syndrome (GLUT1-DS) is caused by a defect in glucose transport across the blood-brain barrier. The main symptoms are epilepsy, developmental delay, movement disorders, and deceleration of head circumference. A ketogenic diet has been shown to be effective in controlling epilepsy in GLUT1-DS. We report a female…

  6. Electric transport in N-type Fe2O3

    NARCIS (Netherlands)

    Acket, G.A.; Volger, J.

    Resistivity, Seebeck-coefficient, Hall-coefficient and magneto-resistance of n-type single crystal ferric oxide (hematite), containing Sn4+ as an impurity, are reported. The resistivity does not show important anisotropy. The Hall- and magneto-resistance effects are probably related to the parasitic

  7. Assessment of the radiological risks of road transport accidents involving type A package shipments

    International Nuclear Information System (INIS)

    Lange, F.; Fett, H.J.; Schwarz, G.; Raffestin, D.; Schneider, T.; Gelder, R.; Hughes, J.S.; Shaw, K.B.; Hedberg, B.; Simenstad, P.; Svahn, B.; Hienen, J.F.A.; Jansma, R.

    1998-01-01

    This paper is an account of work performed within a multi-lateral research project on the radiological risks associated with the transportation of Type A packaged radioactive material. The research project has been performed on behalf of the European Commission and various national agencies of the participating countries and involved organizations and institutes of five EU Member States, France, Germany, The Netherlands, Sweden, and the UK. The main objectives of the research project were the assessment and appraisal of the potential radiological risks of road transport accidents involving Type A package shipments in participating EU Member States. Data were collected and include harmonized sets information related to the type, quantity and characteristics of Type A package shipments by road. Such databases were basically non-existent until recently. The results are expected to be valuable to both national agencies and international organizations, with responsibilities for the safe transport of radioactive materials by providing some insight in the carriage of radioactive materials by road making up a major fraction of radioactive material transports. Similarly, a wide body of information has been collected and compiled on road transport accidents in terms of the frequency of occurrence and the severity of accidental impact loads potentially experienced by a Type A package.In addition, the results will facilitate judgement of the adequacy of the IAEA Transport Regulations as far as Type A packages are concerned. (O.M.)

  8. Marketing Research of Construction Sites based on ABC-XYZ Analysis and Relational Data

    Directory of Open Access Journals (Sweden)

    Konikov Aleksandr

    2017-01-01

    Full Text Available ABC-XYZ analysis is well known in marketing. It allows identifying sites that yield maximum profits when sold, sites that enjoy stable demand, or sites have both qualities specified above. However, the methods are quite abstract and are not designed to study specific factors that impact the results of ABC-XYZ analysis. Meanwhile, for some applications, particularly for marketing research of construction sites, it is critical not only to identify high-profit and stable sites but also to find out what combination of technical parameters, factors related to their location, transport accessibility, etc. are typical of them. This work suggests an approach to address the issue.

  9. A mathematical model of amphibian skin epithelium with two types of transporting cellular units

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E

    1985-01-01

    A computer model of ion transport across amphibian skin epithelium containing two types of cellular units, their relative number and sizes, and a paracellular pathway has been developed. The two cellular units are, a large Na+ transporting compartment representing the major epithelium from stratum...... granulosum to str. germinativum, and a small, Cl- transporting compartment representing the mitochondria rich cell. The cellular units both contain dissipative and active pathways according to the two-membrane model. The Na+ transporting unit includes a (Na+, K+, 2 Cl-) co-transport system in the inward...... facing membrane. The outward facing membrane of the Cl- transporting units contains a potential gated Cl- permeability. Effects of ion distributions and changes in gating variables on the time course of transepithelial voltage clamp currents and their steady states are analyzed. The model predicts...

  10. Semiclassical theory of anomalous transport in type-II topological Weyl semimetals

    Science.gov (United States)

    McCormick, Timothy M.; McKay, Robert C.; Trivedi, Nandini

    2017-12-01

    Weyl semimetals possess low-energy excitations which act as monopoles of Berry curvature in momentum space. These emergent monopoles are at the heart of the many novel transport properties that Weyl semimetals exhibit. The singular nature of the Berry curvature around the nodal points in Weyl semimetals allows for the possibility of large anomalous transport coefficients in zero applied magnetic field. Recently, a new class, termed type-II Weyl semimetals, has been demonstrated in a variety of materials, where the Weyl nodes are tilted. We present here a theoretical study of anomalous transport in this new class of Weyl semimetals. We find that the parameter governing the tilt of these type-II Weyl points is intimately related to the zero-field transverse transport properties. We also find that the temperature dependence of the chemical potential plays an important role in determining how the transport coefficients can effectively probe the Berry curvature of the type-II Weyl points. In particular, we find that the transverse thermoelectric transport coefficient Lxy E T is strongly enhanced with the tilt of the type-II Weyl nodes and with increasing temperature. We also discuss the experimental implications of our work for time-reversal breaking type-II Weyl semimetals.

  11. Type B plutonium transport package development that uses metallic filaments and composite materials

    International Nuclear Information System (INIS)

    Pierce, J.D.; Moya, J.L.; McClure, J.D.; Hohnstreiter, G.F.; Golliher, K.G.

    1992-01-01

    A new design concept for a Type B transport packaging for transporting plutonium and uranium has been developed by the Transportation Systems Department at Sandia National Laboratories (SNL). The new design came about following a review of current packagings, projected future transportation needs, and current and future regulatory requirements. United States packaging, regulations specified in Title 49, Code of Federal Regulations Parts 173.416 and 173.417 (for fissile materials) offer parallel paths under the heading of authorized Type B packages for the transport of greater than A 1 or A 2 quantities of radioactive material. These pathways are for certified Type B packagings and specification packagings. Consequently, a review was made of both type B and specification packages. A request for comment has been issued by the US Nuclear Regulatory Commission (NRC) for proposed changes to Title 10, Code of Federal Regulations Part 71. These regulations may therefore change in the near future. The principle proposed regulation change that would affect this type of package is the addition of a dynamic crush requirement for certain packagings. The US Department of Transportation (DOT) may also re-evaluate the specifications in 49 CFR that authorize the fabrication and use of specification packagings. Therefore, packaging, options were considered that will meet expected new regulations and provide shipment capability for the US Department of Energy well into the future

  12. A novel ATP-binding cassette transporter is responsible for resistance to viologen herbicides in the cyanobacterium Synechocystis sp. PCC 6803

    Czech Academy of Sciences Publication Activity Database

    Prosecká, J.; Orlov, V. N.; Fantin, Y. S.; Zinchenko, V. V.; Babykin, M. M.; Tichý, Martin

    2009-01-01

    Roč. 276, č. 15 (2009), s. 4001-4011 ISSN 1742-464X R&D Projects: GA MŠk ME 881 Institutional research plan: CEZ:AV0Z50200510 Keywords : ABC-type transporter * cyanobacteria * oxidative stress Subject RIV: EE - Microbiology, Virology Impact factor: 3.042, year: 2009

  13. The prospects of use of alternative types of fuel in road transport ...

    African Journals Online (AJOL)

    The article is devoted to the analysis of possibilities of using alternative types of fuel in transport. Gas engine fuels are considered as potential energy carriers for diesel engines. Since the constructions of vehicles, using gas and traditional types of fuel, have some differences, the most important are the issues of ensuring ...

  14. Potassium transport of Salmonella is important for type III secretion and pathogenesis

    Science.gov (United States)

    Liu, Yehao; Ho, Katharina Kim; Su, Jing; Gong, Hao; Chang, Alexander C.

    2013-01-01

    Intracellular cations are essential for the physiology of all living organisms including bacteria. Cations such as potassium ion (K+), sodium ion (Na+) and proton (H+) are involved in nearly all aspects of bacterial growth and survival. K+ is the most abundant cation and its homeostasis in Escherichia coli and Salmonella is regulated by three major K+ transporters: high affinity transporter Kdp and low affinity transporters Kup and Trk. Previous studies have demonstrated the roles of cations and cation transport in the physiology of Escherichia coli; their roles in the virulence and physiology of pathogenic bacteria are not well characterized. We have previously reported that the Salmonella K+ transporter Trk is important for the secretion of effector proteins of the type III secretion system (TTSS) of Salmonella pathogenicity island 1 (SPI-1). Here we further explore the role of Salmonella cation transport in virulence in vitro and pathogenesis in animal models. Impairment of K+ transport through deletion of K+ transporters or exposure to the chemical modulators of cation transport, gramicidin and valinomycin, results in a severe defect in the TTSS of SPI-1, and this defect in the TTSS was not due to a failure to regulate intrabacterial pH or ATP. Our results also show that K+ transporters are critical to the pathogenesis of Salmonella in mice and chicks and are involved in multiple growth and virulence characteristics in vitro, including protein secretion, motility and invasion of epithelial cells. These results suggest that cation transport of the pathogenic bacterium Salmonella, especially K+ transport, contributes to its virulence in addition to previously characterized roles in maintaining homeostasis of bacteria. PMID:23728623

  15. Preliminary Analysis of Radiation Shielding for B-type HIC Transport Package

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dohyung; Lee, Unjang; Ko, Jaehoon; Choi, Kyu-Sup [Korea Nuclear Engineering and Service Corporation, Seoul (Korea, Republic of)

    2007-10-15

    A radiation shielding analysis has been conducted using a computer program MCNP5 for a B-type HIC (High Integrated Container) Transport Package, which contains HIC with radioactive waste or Spent Resin, for transportation from nuclear power plant sites to disposal repository. Radiation source term is first carefully determined from the safety analysis reports related to HIC for appropriate calculation. And then MCNP (v.5) is performed to obtain the minimum thickness of HIC transport package, which meets the dose rate limit for HIC transport package prescribed in Korea Nuclear Law and IAEA Safety Standards for Radioactive Material Transport. In addition, some other analyses are done about the trend of dose rates depending on the thickness of shielding material and distance from the package.

  16. An Electrically Tight In Vitro Blood-Brain Barrier Model Displays Net Brain-to-Blood Efflux of Substrates for the ABC Transporters, P-gp, Bcrp and Mrp-1

    DEFF Research Database (Denmark)

    Helms, Hans Christian; Hersom, Maria; Kuhlmann, Louise Borella

    2014-01-01

    if a bovine endothelial/rat astrocyte in vitro BBB co-culture model displayed polarized transport of known efflux transporter substrates. The co-culture model displayed low mannitol permeabilities of 0.95 ± 0.1 · 10(-6) cm·s(-1) and high transendothelial electrical resistances of 1,177 ± 101 Ω·cm(2...

  17. ABC model and the management of costs

    Directory of Open Access Journals (Sweden)

    Pravdić Predrag

    2016-01-01

    Full Text Available When a company has multiple objectives at the same time, they all must be considered and balanced when making any business decisions. Linking the markets, capital and resources so as to thus ensure the highest yield is, In fact, the search for competitive advantage as a basic condition for survival in a market economy. In highly detailed systems based on the management of costs or ABC (activity based costing systems, the cost of activities often result in erroneous evaluation of aggregate costs of the action. Improvements in information technology and monitoring decrease of technology costs enabled the ABC system to become a feasible system calculating costs in many organizations.

  18. Analysis and model testing of a Super Tiger Type B waste transport system in accident environments

    International Nuclear Information System (INIS)

    May, R.A.; Yoshimura, H.R.; Romesberg, L.E.; Joseph, B.J.

    1980-01-01

    Sandia National Laboratories is investigating the response of a Type B packaging containing drums of contact-handled transuranic waste (CH-TRU) as a part of a program to evaluate the adequacy of experimental and analytical methods for assessing the safety of waste transport systems in accident environments. A US NRC certified Type B package known as the Super Tiger was selected for the study. This overpack consists of inner and outer steel shells separated by rigid polyurethane foam and can be used for either highway or rail transportation. Tests using scale models of the vehicular system are being conducted in conjunction with computer analyses

  19. Transvascular low-density lipoprotein transport in patients with diabetes mellitus (type 2)

    DEFF Research Database (Denmark)

    Kornerup, Karen; Nordestgaard, Børge Grønne; Feldt-Rasmussen, Bo

    2002-01-01

    accumulation and, thus, atherosclerosis. METHODS AND RESULTS: We developed an in vivo method for measurement of transvascular transport of low density lipoprotein (LDL) and applied it in 16 patients with maturity-onset diabetes (type 2) and 29 healthy control subjects. Autologous 131I-labeled LDL...... plasma insulin levels in diabetic patients. CONCLUSIONS: Transvascular LDL transport may be increased in patients with type 2 diabetes. This suggests that lipoprotein flux into the arterial wall is increased in people with diabetes, possibly explaining the accelerated development of atherosclerosis....... in patients with diabetes and control subjects, respectively (P2.5%/h and 5.3+/-1.6%/h (P

  20. The ABC-paradox: is Time Driven ABC relevant for small and Medium sized enterprises (SME)?

    DEFF Research Database (Denmark)

    Fladkjær, Henrik Find; Jensen, Erling

    -books and in curriculum at most business schools. But ABC is not used very much by the compa-nies. Especially in small and medium enterprises ABC is rarely implemented. This is primarily due to two things: First, the ABC model is too difficult to implement. Second, the data foundation for the model is not available...... in the required quality in the ERP systems used by the businesses. In this article we will explore ways of overcoming these two related problems. We will explore these issues particularly in relation to small and medium enterprises. Through a theoretical analysis and practical implementation in a medium sized...... manufacturing company we will analyse whether it is possible to create a satisfactory decision making foundation using a TDABC as a less complex cost model in the company. We have analysed our way to the conclusion that compared to ABC, the TDABC model provides the management with a number of pragmatic...

  1. Regulation of expression of the tricarballylate utilization operon (tcuABC) of Salmonella enterica

    OpenAIRE

    Lewis, Jeffrey A.; Stamper, Lisa W.; Escalante-Semerena, Jorge C.

    2009-01-01

    The tricarballylate utilization locus (tcuRABC) of Salmonella enterica serovar Typhimurium is comprised of a 3-gene operon (tcuABC) that encodes functions that allow this bacterium to use tricarballylate as a source of carbon and energy, and the tcuR gene, which encodes a putative LysR-type transcriptional regulator. In our studies, transcription of the tcuABC operon peaked at mid-log phase, and declined moderately during stationary phase. This pattern was not due to a change in the amount of...

  2. Amino Acid Transporters and Release of Hydrophobic Amino Acids in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120

    Directory of Open Access Journals (Sweden)

    Rafael Pernil

    2015-04-01

    Full Text Available Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can use inorganic compounds such as nitrate or ammonium as nitrogen sources. In the absence of combined nitrogen, it can fix N2 in differentiated cells called heterocysts. Anabaena also shows substantial activities of amino acid uptake, and three ABC-type transporters for amino acids have been previously characterized. Seven new loci encoding predicted amino acid transporters were identified in the Anabaena genomic sequence and inactivated. Two of them were involved in amino acid uptake. Locus alr2535-alr2541 encodes the elements of a hydrophobic amino acid ABC-type transporter that is mainly involved in the uptake of glycine. ORF all0342 encodes a putative transporter from the dicarboxylate/amino acid:cation symporter (DAACS family whose inactivation resulted in an increased uptake of a broad range of amino acids. An assay to study amino acid release from Anabaena filaments to the external medium was set up. Net release of the alanine analogue α-aminoisobutyric acid (AIB was observed when transport system N-I (a hydrophobic amino acid ABC-type transporter was engaged in the uptake of a specific substrate. The rate of AIB release was directly proportional to the intracellular AIB concentration, suggesting leakage from the cells by diffusion.

  3. The influence of the type of road, the type of vehicle and the age structure on the road transport emission

    Directory of Open Access Journals (Sweden)

    Aleksandra KUTRZYK

    2010-01-01

    Full Text Available The total emission level is heavily dependent on the number of vehicles. Additionally, the type of vehicles and their age structures are very important. The structure of vehicles also depends on the type of the road. The article presents the results of calculations of the pollutants emission from the road transport. Total emission was calculated with combination of the investigation results i.e. the type of vehicles and their age structures for different types of roads. The investigations have been made for different classes of roads with different types of vehicles. The traffic line has been recorded in the same length of time. On the basis of analysis of the recorded traffic line, the number and the type of vehicles have been estimated. The classification of vehicles have been made according to the level of emission i.e. passenger cars, light duty vehicles, heavy duty vehicles, busses and others, taking into consideration the age structures of vehicles. The level of total traffic emission has been calculated on the basis of results. There has been used the Copert programme methodology. The results of the calculations have been made with combination of the type of road, the speed of vehicles, the type of vehicles and their age structure, are presented.

  4. Functional and cytometric examination of different human lung epithelial cell types as drug transport barriers.

    Science.gov (United States)

    Min, Kyoung Ah; Rosania, Gus R; Kim, Chong-Kook; Shin, Meong Cheol

    2016-03-01

    To develop inhaled medications, various cell culture models have been used to examine the transcellular transport or cellular uptake properties of small molecules. For the reproducible high throughput screening of the inhaled drug candidates, a further verification of cell architectures as drug transport barriers can contribute to establishing appropriate in vitro cell models. In the present study, side-by-side experiments were performed to compare the structure and transport function of three lung epithelial cells (Calu-3, normal human bronchial primary cells (NHBE), and NL-20). The cells were cultured on the nucleopore membranes in the air-liquid interface (ALI) culture conditions, with cell culture medium in the basolateral side only, starting from day 1. In transport assays, paracellular transport across all three types of cells appeared to be markedly different with the NHBE or Calu-3 cells, showing low paracellular permeability and high TEER values, while the NL-20 cells showed high paracellular permeability and low TEER. Quantitative image analysis of the confocal microscope sections further confirmed that the Calu-3 cells formed intact cell monolayers in contrast to the NHBE and NL-20 cells with multilayers. Among three lung epithelial cell types, the Calu-3 cell cultures under the ALI condition showed optimal cytometric features for mimicking the biophysical characteristics of in vivo airway epithelium. Therefore, the Calu-3 cell monolayers could be used as functional cell barriers for the lung-targeted drug transport studies.

  5. ABC – Advocates for Breast Cancer

    African Journals Online (AJOL)

    Cancer 2008;113(S8):221-224. [http://dx.doi.org/10.1002/cncr.23844]. ARTICLE. ABC – Advocates for Breast Cancer. A Steyn,1 Dip DA (Lond), LRAM (Speech and Drama) (Lond); J du Plessis;2 S Meyer,3 MSocSc (SW). 1 Immediate Past President, Reach to Recovery International, Queensland, Australia. 2 Chief Executive ...

  6. Red phosphorescent organic light-emitting diodes using pyridine based electron transport type triplet host materials

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Soon Ok [Department of Polymer Science and Engineering, Dankook University, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of); Lee, Jun Yeob, E-mail: leej17@dankook.ac.kr [Department of Polymer Science and Engineering, Dankook University, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do 448-701 (Korea, Republic of)

    2011-05-16

    Research highlights: {yields} Pyridine based host material for red phosphorescent organic light emitting diode. {yields} Device optimization at low doping concentration of 2%. {yields} Simplified red phosphorescent organic light emitting diodes. - Abstract: Pyridine based electron transport type host materials were developed and their device performances were investigated according to doping concentration. The pyridine substituent was combined with a spirofluorenebenzofluorene core unit and a high quantum efficiency of 13.3% was achieved in red phosphorescent organic light-emitting diodes at a low doping concentration of 2%. A simple red device without any electron transport layer could be fabricated and a simple device without any electron transport layer showed better power efficiency than the standard device with an electron transport layer.

  7. Structure and mechanism of Zn2+-transporting P-type ATPases

    DEFF Research Database (Denmark)

    Wang, Kaituo; Sitsel, Oleg; Meloni, Gabriele

    2014-01-01

    A) are crucial for cellular redistribution and detoxification of Zn2+ and related elements2, 3. Here we present crystal structures representing the phosphoenzyme ground state (E2P) and a dephosphorylation intermediate (E2·Pi) of ZntA from Shigella sonnei, determined at 3.2 Å and 2.7 Å resolution, respectively....... The structures reveal a similar fold to Cu+-ATPases, with an amphipathic helix at the membrane interface. A conserved electronegative funnel connects this region to the intramembranous high-affinity ion-binding site and may promote specific uptake of cellular Zn2+ ions by the transporter. The E2P structure...... been proposed for H+-ATPases. Indeed, transport studies in liposomes provide experimental support for ZntA activity without counter transport. These findings suggest a mechanistic link between PIB-type Zn2+-ATPases and PIII-type H+-ATPases and at the same time show structural features...

  8. Light harvesting and chloroplast electron transport in NADP-malic enzyme type C4 plants.

    Science.gov (United States)

    Nakajima Munekage, Yuri

    2016-06-01

    The structure of thylakoids in chloroplasts and the organization of the electron transport chain changed dynamically during the evolution of C4 photosynthesis, especially in the nicotinamide adenine dinucleotide phosphate (NADP)-malic enzyme type C4 species. Stacked grana membranes are strongly reduced in the bundle sheath chloroplasts of these plants, where photosystem II activity is diminished and cyclic electron transport around photosystem I mainly occurs. This change optimizes the ATP/NADPH production ratio in bundle sheath chloroplasts to drive the metabolic cycle of C4 photosynthesis. This review summarizes the current model of light harvesting and electron transport in the NADP-malic enzyme type C4 plants and discusses how it changed during the evolution of C4 photosynthesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. The Putative Response Regulator BaeR Stimulates Multidrug Resistance of Escherichia coli via a Novel Multidrug Exporter System, MdtABC

    OpenAIRE

    Nagakubo, Satoshi; Nishino, Kunihiko; Hirata, Takahiro; Yamaguchi, Akihito

    2002-01-01

    Overproduction of the response regulator BaeR confers resistance to novobiocin and bile salts in a ΔacrAB mutant by stimulating drug exporter gene expression. The mdtABC (multidrug transporter ABC, formerly known as yegMNO) genes, which encode a resistance-nodulation-cell division (RND) drug efflux system, are responsible for resistance. The MdtABC system comprises the transmembrane MdtB/MdtC heteromultimer and MdtA membrane fusion protein. MdtAC also confers bile salt, but not novobiocin, re...

  10. Regulatory pathways for ATP-binding cassette transport proteins in kidney proximal tubules

    NARCIS (Netherlands)

    Masereeuw, R.; Russel, F.G.M.

    2012-01-01

    The ATP-binding cassette transport proteins (ABC transporters) represent important determinants of drug excretion. Protective or excretory tissues where these transporters mediate substrate efflux include the kidney proximal tubule. Regulation of the transport proteins in this tissue requires

  11. Accuracy of the ABC/2 Score for Intracerebral Hemorrhage: Systematic Review and Analysis of MISTIE, CLEAR-IVH, and CLEAR III.

    Science.gov (United States)

    Webb, Alastair J S; Ullman, Natalie L; Morgan, Tim C; Muschelli, John; Kornbluth, Joshua; Awad, Issam A; Mayo, Stephen; Rosenblum, Michael; Ziai, Wendy; Zuccarrello, Mario; Aldrich, Francois; John, Sayona; Harnof, Sagi; Lopez, George; Broaddus, William C; Wijman, Christine; Vespa, Paul; Bullock, Ross; Haines, Stephen J; Cruz-Flores, Salvador; Tuhrim, Stan; Hill, Michael D; Narayan, Raj; Hanley, Daniel F

    2015-09-01

    The ABC/2 score estimates intracerebral hemorrhage (ICH) volume, yet validations have been limited by small samples and inappropriate outcome measures. We determined accuracy of the ABC/2 score calculated at a specialized reading center (RC-ABC) or local site (site-ABC) versus the reference-standard computed tomography-based planimetry (CTP). In Minimally Invasive Surgery Plus Recombinant Tissue-Type Plasminogen Activator for Intracerebral Hemorrhage Evacuation-II (MISTIE-II), Clot Lysis Evaluation of Accelerated Resolution of Intraventricular Hemorrhage (CLEAR-IVH) and CLEAR-III trials. ICH volume was prospectively calculated by CTP, RC-ABC, and site-ABC. Agreement between CTP and ABC/2 was defined as an absolute difference up to 5 mL and relative difference within 20%. Determinants of ABC/2 accuracy were assessed by logistic regression. In 4369 scans from 507 patients, CTP was more strongly correlated with RC-ABC (r(2)=0.93) than with site-ABC (r(2)=0.87). Although RC-ABC overestimated CTP-based volume on average (RC-ABC, 15.2 cm(3); CTP, 12.7 cm3), agreement was reasonable when categorized into mild, moderate, and severe ICH (κ=0.75; PABC (84% within 5 mL; 48% of scans within 20%) than for site-ABC (81% within 5 mL; 41% within 20%). RC-ABC had moderate accuracy for detecting ≥5 mL change in CTP volume between consecutive scans (sensitivity, 0.76; specificity, 0.86) and was more accurate with smaller ICH, thalamic hemorrhage, and homogeneous clots. ABC/2 scores at local or central sites are sufficiently accurate to categorize ICH volume and assess eligibility for the CLEAR-III and MISTIE III studies and moderately accurate for change in ICH volume. However, accuracy decreases with large, irregular, or lobar clots. URL: http://www.clinicaltrials.gov. Unique identifier: MISTIE-II NCT00224770; CLEAR-III NCT00784134. © 2015 American Heart Association, Inc.

  12. Membrane transport mechanism 3D structure and beyond

    CERN Document Server

    Ziegler, Christine

    2014-01-01

    This book provides a molecular view of membrane transport by means of numerous biochemical and biophysical techniques. The rapidly growing number of atomic structures of transporters in different conformations and the constant progress in bioinformatics have recently added deeper insights.   The unifying mechanism of energized solute transport across membranes is assumed to consist of the conformational cycling of a carrier protein to provide access to substrate binding sites from either side of a cellular membrane. Due to the central role of active membrane transport there is considerable interest in deciphering the principles of one of the most fundamental processes in nature: the alternating access mechanism.   This book brings together particularly significant structure-function studies on a variety of carrier systems from different transporter families: Glutamate symporters, LeuT-like fold transporters, MFS transporters and SMR (RND) exporters, as well as ABC-type importers.   The selected examples im...

  13. Tripartite ATP-Independent Periplasmic (TRAP Transporters and Tripartite Tricarboxylate Transporters (TTT: From Uptake to Pathogenicity

    Directory of Open Access Journals (Sweden)

    Leonardo T. Rosa

    2018-02-01

    Full Text Available The ability to efficiently scavenge nutrients in the host is essential for the viability of any pathogen. All catabolic pathways must begin with the transport of substrate from the environment through the cytoplasmic membrane, a role executed by membrane transporters. Although several classes of cytoplasmic membrane transporters are described, high-affinity uptake of substrates occurs through Solute Binding-Protein (SBP dependent systems. Three families of SBP dependant transporters are known; the primary ATP-binding cassette (ABC transporters, and the secondary Tripartite ATP-independent periplasmic (TRAP transporters and Tripartite Tricarboxylate Transporters (TTT. Far less well understood than the ABC family, the TRAP transporters are found to be abundant among bacteria from marine environments, and the TTT transporters are the most abundant family of proteins in many species of β-proteobacteria. In this review, recent knowledge about these families is covered, with emphasis on their physiological and structural mechanisms, relating to several examples of relevant uptake systems in pathogenicity and colonization, using the SiaPQM sialic acid uptake system from Haemophilus influenzae and the TctCBA citrate uptake system of Salmonella typhimurium as the prototypes for the TRAP and TTT transporters, respectively. High-throughput analysis of SBPs has recently expanded considerably the range of putative substrates known for TRAP transporters, while the repertoire for the TTT family has yet to be fully explored but both types of systems most commonly transport carboxylates. Specialized spectroscopic techniques and site-directed mutagenesis have enriched our knowledge of the way TRAP binding proteins capture their substrate, while structural comparisons show conserved regions for substrate coordination in both families. Genomic and protein sequence analyses show TTT SBP genes are strikingly overrepresented in some bacteria, especially in the

  14. Agrobacterium tumefaciens Zur Regulates the High-Affinity Zinc Uptake System TroCBA and the Putative Metal Chaperone YciC, along with ZinT and ZnuABC, for Survival under Zinc-Limiting Conditions.

    Science.gov (United States)

    Chaoprasid, Paweena; Dokpikul, Thanittra; Johnrod, Jaruwan; Sirirakphaisarn, Sirin; Nookabkaew, Sumontha; Sukchawalit, Rojana; Mongkolsuk, Skorn

    2016-06-15

    Agrobacterium tumefaciens has a cluster of genes (Atu3178, Atu3179, and Atu3180) encoding an ABC-type transporter, here named troA, troB, and troC, respectively, which is shown here to be a zinc-specific uptake system. Reverse transcription (RT)-PCR analysis confirmed that troA, troB, and troC are cotranscribed, with troC as the first gene of the operon. The yciC (Atu3181) gene is transcribed in the opposite orientation to that of the troCBA operon and belongs to a metal-binding GTPase family. Expression of troCBA and yciC was inducible under zinc-limiting conditions and was controlled by the zinc uptake regulator, Zur. Compared to the wild type, the mutant strain lacking troC was hypersensitive to a metal chelator, EDTA, and the phenotype could be rescued by the addition of zinc, while the strain with a single yciC mutation showed no phenotype. However, yciC was important for survival under zinc limitation when either troC or zinT was inactivated. The periplasmic zinc-binding protein, ZinT, could not function when TroC was inactivated, suggesting that ZinT may interact with TroCBA in zinc uptake. Unlike many other bacteria, the ABC-type transporter ZnuABC was not the major zinc uptake system in A. tumefaciens However, the important role of A. tumefaciens ZnuABC was revealed when TroCBA was impaired. The strain containing double mutations in the znuA and troC genes exhibited a growth defect in minimal medium. A. tumefaciens requires cooperation of zinc uptake systems and zinc chaperones, including TroCBA, ZnuABC, ZinT, and YciC, for survival under a wide range of zinc-limiting conditions. Both host and pathogen battle over access to essential metals, including zinc. In low-zinc environments, physiological responses that make it possible to acquire enough zinc are important for bacterial survival and could determine the outcome of host-pathogen interactions. A. tumefaciens was found to operate a novel pathway for zinc uptake in which ZinT functions in concert with

  15. Transport proteins promoting Escherichia coli pathogenesis

    Science.gov (United States)

    Tang, Fengyi; Saier, Milton H.

    2014-01-01

    Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies. PMID:24747185

  16. Transport proteins promoting Escherichia coli pathogenesis.

    Science.gov (United States)

    Tang, Fengyi; Saier, Milton H

    2014-01-01

    Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Molecular Simulation and Biochemical Studies Support an Elevator-type Transport Mechanism in EIIC.

    Science.gov (United States)

    Lee, Jumin; Ren, Zhenning; Zhou, Ming; Im, Wonpil

    2017-06-06

    Enzyme IIC (EIIC) is a membrane-embedded sugar transport protein that is part of the phosphoenolpyruvate-dependent phosphotransferases. Crystal structures of two members of the glucose EIIC superfamily, bcChbC in the inward-facing conformation and bcMalT in the outward-facing conformation, were previously solved. Comparing the two structures led us to the hypothesis that sugar translocation could be achieved by an elevator-type transport mechanism in which a transport domain binds to the substrate and, through rigid body motions, transports it across the membrane. To test this hypothesis and to obtain more accurate descriptions of alternate conformations of the two proteins, we first performed collective variable-based steered molecular dynamics (CVSMD) simulations starting with the two crystal structures embedded in model lipid bilayers, and steered their transport domain toward their own alternative conformation. Our simulations show that large rigid-body motions of the transport domain (55° in rotation and 8 Å in translation) lead to access of the substrate binding site to the alternate side of the membrane. H-bonding interactions between the sugar and the protein are intact, although the side chains of the binding-site residues were not restrained in the simulation. Pairs of residues in bcMalT that are far apart in the crystal structure become close to each other in the simulated model. Some of these pairs can be cross-linked by a mercury ion when mutated to cysteines, providing further support for the CVSMD-generated model. In addition, bcMalT binds to maltose with similar affinities before and after the cross-linking, suggesting that the binding site is preserved after the conformational change. In combination, these results support an elevator-type transport mechanism in EIIC. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  18. Loss of plastoglobule kinases ABC1K1 and ABC1K3 causes conditional degreening, modified prenyl-lipids, and recruitment of the jasmonic acid pathway

    Science.gov (United States)

    Plastoglobules (PGs) are plastid lipid-protein particles. This study examines the function of PG-localized kinases ABC1K1 and ABC1K3 in Arabidopsis thaliana. Several lines of evidence suggested that ABC1K1 and ABC1K3 form a protein complex. Null mutants for both genes (abc1k1 and abc1k3) and the dou...

  19. Split tasks of asymmetric nucleotide-binding sites in the heterodimeric ABC exporter EfrCD.

    Science.gov (United States)

    Hürlimann, Lea M; Hohl, Michael; Seeger, Markus A

    2017-06-01

    Many heterodimeric ATP-binding cassette (ABC) exporters evolved asymmetric ATP-binding sites containing a degenerate site incapable of ATP hydrolysis due to noncanonical substitutions in conserved sequence motifs. Recent studies revealed that nucleotide binding to the degenerate site stabilizes contacts between the nucleotide-binding domains (NBDs) of the inward-facing transporter and regulates ATP hydrolysis at the consensus site via allosteric coupling mediated by the D-loops. However, it is unclear whether nucleotide binding to the degenerate site is strictly required for substrate transport. In this study, we examined the functional consequences of a systematic set of mutations introduced at the degenerate and consensus site of the multidrug efflux pump EfrCD of Enterococcus faecalis. Mutating motifs which differ among the two ATP-binding sites (Walker B, switch loop, and ABC signature) or which are involved in interdomain communication (D-loop and Q-loop) led to asymmetric results in the functional assays and were better tolerated at the degenerate site. This highlights the importance of the degenerate site to allosterically regulate the events at the consensus site. Mutating invariant motifs involved in ATP binding and NBD closure (A-loop and Walker A) resulted in equally reduced transport activities, regardless at which ATP-binding site they were introduced. In contrast to previously investigated heterodimeric ABC exporters, mutation of the degenerate site Walker A lysine completely inactivated ATPase activity and substrate transport, indicating that ATP binding to the degenerate site is essential for EfrCD. This study provides novel insights into the split tasks of asymmetric ATP-binding sites of heterodimeric ABC exporters. © 2017 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  20. Interactions among the A and T units of an ECF-type biotin transporter analyzed by site-specific crosslinking.

    Directory of Open Access Journals (Sweden)

    Olivia Neubauer

    Full Text Available Energy-coupling factor (ECF transporters are a huge group of micronutrient importers in prokaryotes. They are composed of a substrate-specific transmembrane protein (S component and a module consisting of a moderately conserved transmembrane protein (T component and two ABC ATPase domains (A components. Modules of A and T units may be dedicated to a specific S component or shared by many different S units in an organism. The mode of subunit interactions in ECF transporters is largely unknown. BioMNY, the focus of the present study, is a biotin transporter with a dedicated AT module. It consists of the S unit BioY, the A unit BioM and the T unit BioN. Like all T units, BioN contains two three-amino-acid signatures with a central Arg residue in a cytoplasmic helical region. Our previous work had demonstrated a central role of the two motifs in T units for stability and function of BioMNY and other ECF transporters. Here we show by site-specific crosslinking of pairs of mono-cysteine variants that the Ala-Arg-Ser and Ala-Arg-Gly signatures in BioN are coupling sites to the BioM ATPases. Analysis of 64 BioN-BioM pairs uncovered interactions of both signatures predominantly with a segment of ~13 amino acid residues C-terminal of the Q loop of BioM. Our results further demonstrate that portions of all BioN variants with single Cys residues in the two signatures are crosslinked to homodimers. This finding may point to a dimeric architecture of the T unit in BioMNY complexes.

  1. Interactions among the A and T Units of an ECF-Type Biotin Transporter Analyzed by Site-Specific Crosslinking

    Science.gov (United States)

    Neubauer, Olivia; Reiffler, Christin; Behrendt, Laura; Eitinger, Thomas

    2011-01-01

    Energy-coupling factor (ECF) transporters are a huge group of micronutrient importers in prokaryotes. They are composed of a substrate-specific transmembrane protein (S component) and a module consisting of a moderately conserved transmembrane protein (T component) and two ABC ATPase domains (A components). Modules of A and T units may be dedicated to a specific S component or shared by many different S units in an organism. The mode of subunit interactions in ECF transporters is largely unknown. BioMNY, the focus of the present study, is a biotin transporter with a dedicated AT module. It consists of the S unit BioY, the A unit BioM and the T unit BioN. Like all T units, BioN contains two three-amino-acid signatures with a central Arg residue in a cytoplasmic helical region. Our previous work had demonstrated a central role of the two motifs in T units for stability and function of BioMNY and other ECF transporters. Here we show by site-specific crosslinking of pairs of mono-cysteine variants that the Ala-Arg-Ser and Ala-Arg-Gly signatures in BioN are coupling sites to the BioM ATPases. Analysis of 64 BioN-BioM pairs uncovered interactions of both signatures predominantly with a segment of ∼13 amino acid residues C-terminal of the Q loop of BioM. Our results further demonstrate that portions of all BioN variants with single Cys residues in the two signatures are crosslinked to homodimers. This finding may point to a dimeric architecture of the T unit in BioMNY complexes. PMID:22216173

  2. Design of a type - a transport package for 99Mo-99mTc Coltech generator

    International Nuclear Information System (INIS)

    Kothalkar, Chetan; Suryanarayana, G.V.; Dey, A.C.; Sachdev, S.S.; Choughule, N.; Murali, S.

    2012-01-01

    BRIT is launching a new product called 99 Mo- 99m Tc Coltech generator. The Coltech generator is a devise designed for the transport of 99 Mo radioisotope adsorbed on the acidic alumina in a sealed glass column (max dimensions: 13 mm diameter, 70 mm height) as the primary containment. At hospital end, 99m Tc, the daughter product of 99 Mo, can be eluted out from the generator using saline. The active column is fitted with a leak proof network of stainless steel needles. The glass column carrying 99 Mo is housed inside a lead shielding having minimum thickness of 50 mm all around, which serves as secondary containment. The shielding is housed inside the ABS shell which acts as tertiary containment, also provides protection to the needles, filters etc. Total weight of the generator is 16 kg. Based on the AERB code SC/TR-1 (being revised), 99 Mo- 99m Tc Coltech generator will be transported in a Type-A transport container. A transport package has been designed by following the code SC/TR-1. Principle design of the package is based on the package for transportation of the similar generator produced by POLATOM, Poland and the package is approved by the Polish regulatory authority. Components are manufactured locally taking care of lndian conditions. The package comprised of a MS drum (HOBBOCK) with tamper proof lockable MS lid and a handle to assist in lifting. For absorbing the shock during transportation, the generator assembly is packed inside the two pieces EPS top and bottom support. The package has been designed for transportation by all modes of transport. Since radioactive material is solid in form and sealed a glass column, it has been designed to sustain a free drop test of 1.2 m, in addition to other tests specified in SC/TR-1. During trial batches upto ∼ 1 Ci of 99 Mo generators were produced, packed in the same Type-A package and supplied to local nuclear medicine center RMC, Mumbai in BRIT vehicle in consultation with AERB. The radiometry of the packages

  3. The ABC of ABC-transport in the hyperthermophilic archaeon Pyrococcus furiosus

    NARCIS (Netherlands)

    Koning, S

    2003-01-01

    Living organisms of our earth can be divided into two groups, the prokaryotes and the eukaryotes. Eukaryotic cells have a nucleus, a special compartment in the cell, where the genetic material, the DNA is located. The DNA in the prokaryotic cell is floating freely in the cell. The eukaryotes, that

  4. The ABC transporter ABC40 encodes a phenylacetic acid export system in Penicillium chrysogenum

    NARCIS (Netherlands)

    Weber, Stefan S.; Kovalchuk, Andriy; Bovenberg, Roe A. L.; Driessen, Arnold J. M.

    2012-01-01

    The filamentous fungus Penicillium chrysogenum is used for the industrial production of beta-lactam antibiotics. The pathway for beta-lactam biosynthesis has been resolved and involves the enzyme phenylacetic acid CoA ligase that is responsible for the CoA activation of the side chain precursor

  5. Individualizing Treatment Approaches for Epileptic Patients with Glucose Transporter Type1 (GLUT-1 Deficiency

    Directory of Open Access Journals (Sweden)

    Armond Daci

    2018-01-01

    Full Text Available Monogenic and polygenic mutations are important contributors in patients suffering from epilepsy, including metabolic epilepsies which are inborn errors of metabolism with a good respond to specific dietetic treatments. Heterozygous variation in solute carrier family 2, facilitated glucose transporter member 1 (SLC2A1 and mutations of the GLUT1/SLC2A2 gene results in the failure of glucose transport, which is related with a glucose type-1 transporter (GLUT1 deficiency syndrome (GLUT1DS. GLUT1 deficiency syndrome is a treatable disorder of glucose transport into the brain caused by a variety of mutations in the SLC2A1 gene which are the cause of different neurological disorders also with different types of epilepsy and related clinical phenotypes. Since patients continue to experience seizures due to a pharmacoresistance, an early clinical diagnosis associated with specific genetic testing in SLC2A1 pathogenic variants in clinical phenotypes could predict pure drug response and might improve safety and efficacy of treatment with the initiation of an alternative energy source including ketogenic or analog diets in such patients providing individualized strategy approaches.

  6. Effects of road type during transport on lamb welfare and meat quality in dry hot climates.

    Science.gov (United States)

    Miranda-de la Lama, Genaro C; Monge, Paula; Villarroel, Morris; Olleta, Jose Luis; García-Belenguer, Sylvia; María, Gustavo A

    2011-06-01

    This study determined whether transporting lambs on paved (PR) or unpaved roads (UR) for 3 h had an effect on plasma stress indicators (cortisol, lactate, glucose, creatine kinase [CK], red blood cells, white blood cells, hematocrit, and neutrophil/lymphocyte [N/L] ratio) and instrumental meat quality (pH24, bruising score, water holding capacity [WHC], color, and texture). A total of 48 Rasa Aragonesa male lambs were used that were approximately 100 days old (12.5 kg ± 1.64, carcass weight). The results suggest that transport on unpaved roads had a significant influence on physiological and hematological stress parameters. Road type had a significant effect on all variables, except for white and red blood cells, and hematocrit levels. The UR lambs had significantly higher (at least p ≤ 0.01) cortisol, lactate, glucose, and CK levels and a higher N/L ratio than PR lambs. Meat from UR lambs had some dark-cutting characteristics, with a darker color, higher ultimate pH, and higher tenderness values than PR. In conclusion, lambs transported on unpaved roads had a more intense stress response and poorer meat quality than lambs transported on paved roads. An effort to improve the logistics associated with route planning is necessary to prevent welfare problems during transport to slaughter.

  7. Assessment of the radiological risks of road transport accidents involving type A-packages

    International Nuclear Information System (INIS)

    Lange, F.; Fett, H.J.; Schwarz, G.; Raffestin, D.; Schneider, T.; Gelder, R.; Hughes, J.S.; Shaw, K.B.; Hedberg, B.; Simenstad, P.; Svahn, B.; Van Hienen, J.F.A.; Jansma, R.

    1998-10-01

    This document, prepared in the framework of a study for the European Commission, presents the evaluation of the risks of accidents associated to the road transport of type A-packages (primarily packages of radio-pharmaceutic or radiography products) for five countries of the European Union. The annual transport of type A-packages varies considerably from one country to another, some countries being producers of radio-pharmaceutic products, others not. These packages are also very different one from each another: the weight varies generally from 1 to 25 kg and the activity from some Mega-Becquerels to few tens of Giga-Becquerels, the average activity expressed in A 2 is 0,01. (A.L.B.)

  8. Asymmetric electron and hole transport in a high-mobility n-type conjugated polymer

    NARCIS (Netherlands)

    Wetzelaer, Gert-Jan A. H.; Kuik, Martijn; Olivier, Yoann; Lemaur, Vincent; Cornil, Jerome; Fabiano, Simone; Loi, Maria Antonietta; Blom, Paul W. M.; Cornil, Jérôme

    2012-01-01

    Electron-and hole-transport properties of the n-type copolymer poly{[N, N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-dithiophene)} [P(NDI2OD-T2), PolyeraActivInk (TM) N2200] are investigated. Electron- and hole-only devices with Ohmic contacts are

  9. Vibrations control of light rail transportation vehicle via PID type fuzzy controller using parameters adaptive method

    OpenAIRE

    METİN, Muzaffer; GÜÇLÜ, Rahmi

    2014-01-01

    In this study, a conventional PID type fuzzy controller and parameter adaptive fuzzy controller are designed to control vibrations actively of a light rail transport vehicle which modeled as 6 degree-of-freedom system and compared performances of these two controllers. Rail vehicle model consists of a passenger seat and its suspension system, vehicle body, bogie, primary and secondary suspensions and wheels. The similarity between mathematical model and real system is shown by compar...

  10. Functional characterization of the Bradyrhizobium japonicum modA and modB genes involved in molybdenum transport.

    Science.gov (United States)

    Delgado, María J; Tresierra-Ayala, Alvaro; Talbi, Chouhra; Bedmar, Eulogio J

    2006-01-01

    A modABC gene cluster that encodes an ABC-type, high-affinity molybdate transporter from Bradyrhizobium japonicum has been isolated and characterized. B. japonicum modA and modB mutant strains were unable to grow aerobically or anaerobically with nitrate as nitrogen source or as respiratory substrate, respectively, and lacked nitrate reductase activity. The nitrogen-fixing ability of the mod mutants in symbiotic association with soybean plants grown in a Mo-deficient mineral solution was severely impaired. Addition of molybdate to the bacterial growth medium or to the plant mineral solution fully restored the wild-type phenotype. Because the amount of molybdate required for suppression of the mutant phenotype either under free-living or under symbiotic conditions was dependent on sulphate concentration, it is likely that a sulphate transporter is also involved in Mo uptake in B. japonicum. The promoter region of the modABC genes has been characterized by primer extension. Reverse transcription and expression of a transcriptional fusion, P(modA)-lacZ, was detected only in a B. japonicum modA mutant grown in a medium without molybdate supplementation. These findings indicate that transcription of the B. japonicum modABC genes is repressed by molybdate.

  11. Identification of Conserved ABC Importers Necessary for Intracellular Survival of Legionella pneumophila in Multiple Hosts

    Directory of Open Access Journals (Sweden)

    Amrita Lama

    2017-11-01

    Full Text Available It is established that the human pathogen Legionella pneumophila becomes significantly augmented for infection of macrophages after intracellular growth in amoebae when compared to like-strains cultivated in laboratory media. Based on this observation, we reasoned that the most critical virulence determinants of L.p. are expressed by responding to stimuli generated by the protozoan host specifically; a process we term “protozoan-priming.” We sought to identify L.p. virulence factors that were required for replication in amoebae in order to highlight the genes necessary for production of the most infectious form of the bacterium. Using a transposon mutagenesis screen, we successfully identified 12 insertions that produced bacteria severely attenuated for growth in amoebae, while retaining a functional Dot/Icm type IVb secretion system. Seven of these insertion mutants were found dispensable for growth in macrophages, revealing attractive therapeutic targets that reside upstream of the pathogen-human interface. Two candidates identified, lpg0730 and lpg0122 were required for survival and replication in amoebae and macrophage host cells. Both genes are conserved among numerous important human pathogenic bacteria that can persist or replicate in amoebae. Each gene encodes a component of an ATP binding cassette (ABC transport complex of unknown function. We demonstrate the lpg0730 ortholog in Francisella tularensis subsp. novicida to be essential for colonization of both protozoan and mammalian host cells, highlighting conserved survival mechanisms employed by bacteria that utilize protozoa as an environmental reservoir for replication.

  12. A putative P-type Cu(2+)-transporting ATPase gene on chromosome II of Saccharomyces cerevisiae.

    Science.gov (United States)

    Rad, M R; Kirchrath, L; Hollenberg, C P

    1994-09-01

    We have sequenced a gene on the right arm near the telomere of chromosome II of Saccharomyces cerevisiae which codes for a putative P-type cation-transporting ATPase (PCA1). The gene codes for a 1216 amino acids protein. The PCA1 gene expresses a 3.5 kb message in both haploid and diploid cells when grown in glucose-based rich medium YPD. The gene product is most similar at the C-terminal region to a human copper-transporting ATPase and Enterococcus hirae copper-transporting ATPases and also an N-terminal dithiol region that was proposed to be a 'metal-binding motif'. Cells lacking PCA1 display no obvious phenotype when tested under standard conditions: whereas they cease growth much earlier than the isogenic wild-type cells in a minimal medium with high copper concentration. Overexpression of PCA1 under GAL1/10 promoter in yeast cells causes poor growth. We also show that yeast strains carrying PCA1 in multiple copies grow slower than isogenic wild-type strains in a minimal synthetic medium containing 0.3 mM-CuSO4.

  13. Response to Bile Salts in Clinical Strains of Acinetobacter baumannii Lacking the AdeABC Efflux Pump: Virulence Associated with Quorum Sensing

    Science.gov (United States)

    López, Maria; Blasco, Lucia; Gato, Eva; Perez, Astrid; Fernández-Garcia, Laura; Martínez-Martinez, Luis; Fernández-Cuenca, Felipe; Rodríguez-Baño, Jesús; Pascual, Alvaro; Bou, German; Tomás, Maria

    2017-01-01

    Introduction: Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of A. baumannii are scarce. Material and Methods: Microbiological and transcriptional studies (arrays and RT-PCR) in the response to bile salts were carried out in isogenic (A. baumanni ΔadeB ATCC 17978 and A. baumannii ΔadeL ATCC 17978) and clinical strains from clone ST79/PFGE-HUI-1 which is characterized by lacking the AdeABC efflux pump and by overexpression the AdeFGH efflux pump. Results and Discussion: In presence of bile salts, in addition to the glutamate/aspartate transporter were found overexpressed in A. baumannii ΔadeB ATCC 17978, the virulence factors (surface motility, biofilm, and Type VI Secretion System) which are associated with activation of the Quorum Sensing system. Overexpression of these factors was confirmed in clinical strains of clone ST79/PFGE-HUI-1. Conclusions: This the first study about the adaptive response to bile salts investigating the molecular and microbiological characteristics in response to bile salts of an isogenic model of A. baumannii ATCC 17978 and clinical isolates of A. baumannii (clinical strains of ST79/PFGE-HUI-1) lacking the main RND efflux pump (AdeABC). Clinical isolates of A. baumannii lacking the AdeABC efflux pump (clone ST79/PFGE-HUI-1) displayed a new clinical profile (increased invasiveness) possibly associated with the response to stress conditions (such as the presence of bile salts). PMID:28536672

  14. Response to Bile Salts in Clinical Strains of Acinetobacter baumannii Lacking the AdeABC Efflux Pump: Virulence Associated with Quorum Sensing.

    Science.gov (United States)

    López, Maria; Blasco, Lucia; Gato, Eva; Perez, Astrid; Fernández-Garcia, Laura; Martínez-Martinez, Luis; Fernández-Cuenca, Felipe; Rodríguez-Baño, Jesús; Pascual, Alvaro; Bou, German; Tomás, Maria

    2017-01-01

    Introduction: Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of A. baumannii are scarce. Material and Methods: Microbiological and transcriptional studies (arrays and RT-PCR) in the response to bile salts were carried out in isogenic ( A. baumanni Δ adeB ATCC 17978 and A. baumannii Δ adeL ATCC 17978) and clinical strains from clone ST79/PFGE-HUI-1 which is characterized by lacking the AdeABC efflux pump and by overexpression the AdeFGH efflux pump. Results and Discussion: In presence of bile salts, in addition to the glutamate/aspartate transporter were found overexpressed in A. baumannii Δ adeB ATCC 17978, the virulence factors (surface motility, biofilm, and Type VI Secretion System) which are associated with activation of the Quorum Sensing system. Overexpression of these factors was confirmed in clinical strains of clone ST79/PFGE-HUI-1. Conclusions: This the first study about the adaptive response to bile salts investigating the molecular and microbiological characteristics in response to bile salts of an isogenic model of A. baumannii ATCC 17978 and clinical isolates of A. baumannii (clinical strains of ST79/PFGE-HUI-1) lacking the main RND efflux pump (AdeABC). Clinical isolates of A. baumannii lacking the AdeABC efflux pump (clone ST79/PFGE-HUI-1) displayed a new clinical profile (increased invasiveness) possibly associated with the response to stress conditions (such as the presence of bile salts).

  15. Effect of the deletion of qmoABC and the promoter distal gene encoding a hypothetical protein on sulfate-reduction in Desulfovibrio vulgaris Hildenborough

    Energy Technology Data Exchange (ETDEWEB)

    Zane, Grant M.; Yen, Huei-chi Bill; Wall, Judy D.

    2010-03-18

    The pathway of electrons required for the reduction of sulfate in sulfate-reducing bacteria (SRB) is not yet fully characterized. In order to determine the role of a transmembrane protein complex suggested to be involved in this process, a deletion of Desulfovibrio vulgaris Hildenborough was created by marker exchange mutagenesis that eliminated four genes putatively encoding the QmoABC complex and a hypothetical protein (DVU0851). The Qmo complex (quinone-interacting membrane-bound oxidoreductase) is proposed to be responsible for transporting electrons to the dissimilatory adenosine-5?phosphosulfate (APS) reductase in SRB. In support of the predicted role of this complex, the deletion mutant was unable to grow using sulfate as its sole electron acceptor with a range of electron donors. To explore a possible role for the hypothetical protein in sulfate reduction, a second mutant was constructed that had lost only the gene that codes for DVU0851. The second constructed mutant grew with sulfate as the sole electron acceptor; however, there was a lag that was not present with the wild-type or complemented strain. Neither deletion strain was significantly impaired for growth with sulfite or thiosulfate as terminal electron acceptor. Complementation of the D(qmoABC-DVU0851) mutant with all four genes or only the qmoABC genes restored its ability to grow by sulfate respiration. These results confirmed the prediction that the Qmo complex is in the electron pathway for sulfate-reduction and revealed that no other transmembrane complex could compensate when Qmo was lacking.

  16. The Role of the Actin Cytoskeleton and Lipid Rafts in the Localization and Function of the ABCC1 Transporter

    Directory of Open Access Journals (Sweden)

    Jan Willem Kok

    2014-01-01

    Full Text Available ATP-binding cassette (ABC transporters are known to be important factors in multidrug resistance of tumor cells. Lipid rafts have been implicated in their localization in the plasma membrane, where they function as drug efflux pumps. This specific localization in rafts may support the activity of ABC/Abc transporters. This raises questions regarding the nature and composition of the lipid rafts that harbor ABC/Abc transporters and the dependence of ABC/Abc transporters—concerning their localization and activity—on lipid raft constituents. Here we review our work of the past 10 years aimed at evaluating whether ABC/Abc transporters are dependent on a particular membrane environment for their function. What is the nature of this membrane environment and which of the lipid raft constituents are important for this dependency? It turns out that cortical actin is of major importance for stabilizing the localization and function of the ABC/Abc transporter, provided it is localized in an actin-dependent subtype of lipid rafts, as is the case for human ABCC1/multidrug resistance-related protein 1 (MRP1 and rodent Abcc1/Mrp1 but not human ABCB1/P-glycoprotein (PGP. On the other hand, sphingolipids do not appear to be modulators of ABCC1/MRP1 (or Abcc1/Mrp1, even though they are coregulated during drug resistance development.

  17. Assessment of the radiological risks of road transport accidents involving Type A packages

    International Nuclear Information System (INIS)

    Lange, F.; Fett, H.J.; Schwarz, G.; Raffestin, D.; Schneider, T.; Gelder, R.; S. Hughes, J.; B. Shaw, K.; Hedberg, B.; Simenstad, P.; Svahn, B.; Heinen, J.F.A. van; Jansma, R.

    2001-01-01

    An assessment and evaluation of the potential radiological risks of transport accidents involving Type A package shipments by road have been performed by five EU Member States, France, Germany, Sweden, The Netherlands, and the UK. The analysis involved collection and analysis of information on a national basis related to the type, volume, and characteristics of Type A package consignments, the associated radioactive traffic, and the expected frequency and consequences of potential vehicular road transport accidents. It was found that the majority of Type A packaged radioactive material shipments by road is related to applications of non-special form radioactive material, i.e. radiopharmaceuticals, radiochemicals etc., in medicine, research, and industry and special form material contained in radiography and other radiation sources, e.g. gauging equipment. The annual volumes of Type A package shipments of radiopharmaceuticals and radiochemicals by road differ considerably between the participating EU Member States from about 12,000 Type A packages in Sweden to about 240,000 in the Netherlands. The broad range reflects to a large extent the supply of radioactive material for the national populations and the production and distribution operations prevailing in the participating EU Member States (some are producer countries, others are not!). Very few standard package designs weighing from about 1-25 kg are predominant in Type A package shipments in all participating countries. Type A packages contain typically a range of radioactivity from a few mega becquerels to a few tens of giga becquerels, the average package activity contents is in terms of fractions of A 2 about 0.01, i.e. about one hundredth of a Type A package contents limits. Based on a probabilistic risk assessment method it has been concluded that the expected frequencies of occurrence of vehicular road transport accidents with the potential to result in an environmental release - including radiologically

  18. Normal conditions of transport thermal analysis and testing of a Type B drum package

    International Nuclear Information System (INIS)

    Jerrell, J.W.; Alstine, M.N. van; Gromada, R.J.

    1995-01-01

    Increasing the content limits of radioactive material packagings can save money and increase transportation safety by decreasing the total number of shipments required to transport large quantities of material. The contents of drum packages can be limited by unacceptable containment vessel pressures and temperatures due to the thermal properties of the insulation. The purpose of this work is to understand and predict the effects of insulation properties on containment system performance. The type B shipping container used in the study is a double containment fiberboard drum package. The package is primarily used to transport uranium and plutonium metals and oxides. A normal condition of transport (NCT) thermal test was performed to benchmark an NCT analysis of the package. A 21 W heater was placed in an instrumented package to simulate the maximum source decay heat. The package reached thermal equilibrium 120 hours after the heater was turned on. Testing took place indoors to minimize ambient temperature fluctuations. The thermal analysis of the package used fiberboard properties reported in the literature and resulted in temperature significantly greater than those measured during the test. Details of the NCT test will be described and transient temperatures at key thermocouple locations within the package will be presented. Analytical results using nominal fiberboard properties will be presented. Explanations of the results and the attempt to benchmark the analysis will be presented. The discovery that fiberboard has an anisotropic thermal conductivity and its effect on thermal performance will also be discussed

  19. Targeting L-type amino acid transporter 1 for anticancer therapy: clinical impact from diagnostics to therapeutics.

    Science.gov (United States)

    Jin, Su-Eon; Jin, Hyo-Eon; Hong, Soon-Sun

    2015-01-01

    L-type amino acid transporter 1 (LAT1) is one of the amino acid transporters. It is overexpressed in various types of cancer cells, while it is produced restrictedly in normal tissues. We discuss its characteristics in cancer cells compared with normal cells. We also mention the current applications to target LAT1 for anticancer therapy focusing on prognostic biomarkers, radio-labeled tumor imaging reagents, amino acid-stapled prodrugs, LAT1-mediated enhanced transport of anticancer drugs and LAT1 inhibitors. LAT1 can be a versatile target to promisingly develop transporter-based drugs with enhanced drug delivery potential for anticancer therapy.

  20. Infection and Transport of Herpes Simplex Virus Type 1 in Neurons: Role of the Cytoskeleton

    Directory of Open Access Journals (Sweden)

    Monica Miranda-Saksena

    2018-02-01

    Full Text Available Herpes simplex virus type 1 (HSV-1 is a neuroinvasive human pathogen that has the ability to infect and replicate within epithelial cells and neurons and establish a life-long latent infection in sensory neurons. HSV-1 depends on the host cellular cytoskeleton for entry, replication, and exit. Therefore, HSV-1 has adapted mechanisms to promote its survival by exploiting the microtubule and actin cytoskeletons to direct its active transport, infection, and spread between neurons and epithelial cells during primary and recurrent infections. This review will focus on the currently known mechanisms utilized by HSV-1 to harness the neuronal cytoskeleton, molecular motors, and the secretory and exocytic pathways for efficient virus entry, axonal transport, replication, assembly, and exit from the distinct functional compartments (cell body and axon of the highly polarized sensory neurons.

  1. Infection and Transport of Herpes Simplex Virus Type 1 in Neurons: Role of the Cytoskeleton

    Science.gov (United States)

    2018-01-01

    Herpes simplex virus type 1 (HSV-1) is a neuroinvasive human pathogen that has the ability to infect and replicate within epithelial cells and neurons and establish a life-long latent infection in sensory neurons. HSV-1 depends on the host cellular cytoskeleton for entry, replication, and exit. Therefore, HSV-1 has adapted mechanisms to promote its survival by exploiting the microtubule and actin cytoskeletons to direct its active transport, infection, and spread between neurons and epithelial cells during primary and recurrent infections. This review will focus on the currently known mechanisms utilized by HSV-1 to harness the neuronal cytoskeleton, molecular motors, and the secretory and exocytic pathways for efficient virus entry, axonal transport, replication, assembly, and exit from the distinct functional compartments (cell body and axon) of the highly polarized sensory neurons. PMID:29473915

  2. Overland Transport of Rotavirus and the Effect of Soil Type and Vegetation

    Directory of Open Access Journals (Sweden)

    Paul C. Davidson

    2016-03-01

    Full Text Available Soil and vegetation are two critical factors for controlling the overland transport kinetics of pathogens in a natural environment. With livestock operations moving more towards concentrated animal operations, the need to dispose of a very large amount of manure in a localized area is becoming increasingly important. Animal manure contains a substantial amount of microbial pathogens, including rotavirus, which may pose a threat of contamination of water resources. This study examined the kinetics of rotavirus in overland transport, with an overall objective of optimizing the design of best management practices, especially vegetative filter strips. The overland transport of rotavirus was studied using three soil types (Catlin silt-loam, Darwin silty-clay, Alvin fine sandy-loam, spanning the entire spectrum of typical Illinois soil textures. A 20-min rainfall event was produced using a small-scale (1.07 m × 0.66 m laboratory rainfall simulator over a soil box measuring 0.610 m × 0.305 m. Each soil type was tested for rotavirus transport kinetics with bare surface conditions, as well as with Smooth Brome and Fescue vegetative covers. Surface runoff, near-surface runoff, soil cores, and vegetation were each analyzed for infective rotavirus particles using cell-culture infectivity assays. Results show that vegetation reduces the recovery of infective rotavirus particles in surface runoff by an average of 73%, in addition to delaying the time to peak recovery. The vegetation, in general, appeared to decrease the recovery of infective rotavirus particles in surface runoff by impeding surface flow and increasing the potential for infiltration into the soil profile.

  3. Nonlinear resonances in the ABC-flow

    Science.gov (United States)

    Didov, A. A.; Uleysky, M. Yu.

    2018-01-01

    In this paper, we study resonances of the ABC-flow in the near integrable case ( C ≪1 ). This is an interesting example of a Hamiltonian system with 3/2 degrees of freedom in which simultaneous existence of two resonances of the same order is possible. Analytical conditions of the resonance existence are received. It is shown numerically that the largest n :1 (n = 1, 2, 3) resonances exist, and their energies are equal to theoretical energies in the near integrable case. We provide analytical and numerical evidences for existence of two branches of the two largest n :1 (n = 1, 2) resonances in the region of finite motion.

  4. The criticality problem in reflected slab type reactor in the two-group transport theory

    International Nuclear Information System (INIS)

    Garcia, R.D.M.

    1978-01-01

    The criticality problem in reflected slab type reactor is solved for the first time in the two group neutron transport theory, by singular eingenfunctions expansion, the singular integrals obtained through continuity conditions of angular distributions at the interface are regularized by a recently proposed method. The result is a coupled system of regular integral equations for the expansion coefficients, this system is solved by an ordinary interactive method. Numerical results that can be utilized as a comparative standard for aproximation methods, are presented [pt

  5. Diversity of transport mechanisms: common structural principles

    NARCIS (Netherlands)

    Driessen, A.J.M.; Rosen, B.P.; Konings, W.N

    2000-01-01

    Traditionally, prokaryotic solute transport systems are classified into major groups based on the energetic requirement of the transport process. These include the secondary transporters that are driven by a proton or sodium motive force, and the ATP-binding cassette (ABC) primary transporters,

  6. Measuring Academic Behavioural Confidence: The ABC Scale Revisited

    Science.gov (United States)

    Sander, Paul; Sanders, Lalage

    2009-01-01

    The Academic Behavioural Confidence (ABC) scale has been shown to be valid and can be useful to teachers in understanding their students, enabling the design of more effective teaching sessions with large cohorts. However, some of the between-group differences have been smaller than expected, leading to the hypothesis that the ABC scale many not…

  7. Dashboard Auditing of Activity-Based Costing (ABC

    Directory of Open Access Journals (Sweden)

    Sorinel Capusneanu

    2009-03-01

    Full Text Available This article aims to define the dashboard auditing according to the specifics of Activity-Based Costing method (ABC. It describes the main objectives of dashboard auditing, the criteria that a dashboard auditor should meet and the step-by-step stages of the entire dashboard auditing process according to the Activity-Based Costing method (ABC.

  8. Dashboard Auditing of Activity-Based Costing (ABC)

    OpenAIRE

    Sorinel Capusneanu

    2009-01-01

    This article aims to define the dashboard auditing according to the specifics of Activity-Based Costing method (ABC). It describes the main objectives of dashboard auditing, the criteria that a dashboard auditor should meet and the step-by-step stages of the entire dashboard auditing process according to the Activity-Based Costing method (ABC).

  9. Dashboard auditing of ABC (Activity-Based Costing). Theoretical approaches

    OpenAIRE

    Căpuşneanu, Sorinel/I

    2009-01-01

    This article aims to define the dashboard auditing according to the specifics of Activity-Based Costing method (ABC). It describes the main objectives of dashboard auditing, the criteria that a dashboard auditor should meet and the step-by-step stages of the entire dashboard auditing process of an enterprise from steel industry according to the Activity-Based Costing method (ABC).

  10. Transporter-Mediated Drug–Drug Interactions with Oral Antidiabetic Drugs

    Directory of Open Access Journals (Sweden)

    Jörg König

    2011-10-01

    Full Text Available Uptake transporters (e.g., members of the SLC superfamily of solute carriers and export proteins (e.g., members of the ABC transporter superfamily are important determinants for the pharmacokinetics of drugs. Alterations of drug transport due to concomitantly administered drugs that interfere with drug transport may alter the kinetics of drug substrates. In vitro and in vivo studies indicate that many drugs used for the treatment of metabolic disorders and cardiovascular diseases (e.g., oral antidiabetic drugs, statins are substrates for uptake transporters and export proteins expressed in the intestine, the liver and the kidney. Since most patients with type 2 diabetes receive more than one drug, transporter-mediated drug-drug interactions are important molecular mechanisms leading to alterations in oral antidiabetic drug pharmacokinetics with the risk of adverse drug reactions. This review focuses on uptake transporters of the SLCO/SLC21 (OATP and SLC22 (OCT/OAT family of solute carriers and export pumps of the ABC (ATP-binding cassette transporter superfamily (especially P-glycoprotein as well as the export proteins of the SLC47 (MATE family and their role for transporter-mediated drug-drug interactions with oral antidiabetic drugs.

  11. Induction of Heavy-Metal-Transporting CPX-Type ATPases during Acid Adaptation in Lactobacillus bulgaricus▿

    Science.gov (United States)

    Penaud, S.; Fernandez, A.; Boudebbouze, S.; Ehrlich, S. D.; Maguin, E.; van de Guchte, M.

    2006-01-01

    Lactobacillus bulgaricus is a lactic acid bacteria (LAB) that, through the production of lactic acid, gradually acidifies its environment during growth. In the course of this process, L. bulgaricus acquires an improved tolerance to acidity. A survey of the recently established genome sequence shows that this bacterium possesses few of the pH control functions that have been described in other LAB and raises the question of what other mechanisms could be involved in its adaptation to the decreasing environmental pH. In some bacteria other than LAB, ion transport systems have been implicated in acid adaptation. We therefore studied the expression of this type of transport system during acid adaptation in L. bulgaricus by reverse transcription and real-time quantitative PCR and mapped transcription start sites. Intriguingly, the most significantly induced were three ATPases carrying the CPX signature of heavy-metal transporters. Protein homology and the presence of a conserved sequence motif in the promoter regions of the genes encoding these proteins strongly suggest that they are involved in copper homeostasis. Induction of this system is thought to assist in avoiding indirect damage that could result from medium acidification. PMID:16997986

  12. Hybrid-Type Organic Thermoelectric Materials Containing Nanoparticles as a Carrier Transport Promoter

    Science.gov (United States)

    Oshima, Keisuke; Inoue, Junta; Sadakata, Shifumi; Shiraishi, Yukihide; Toshima, Naoki

    2017-05-01

    Carbon nanotubes (CNTs) have recently received much attention as thermoelectric materials. Although the carrier mobility within a single CNT is very high, the charge carrier transport between CNTs is quite slow. We have utilized nanoparticles (NPs) for promotion of the carrier transport between CNTs for improving their thermoelectric performance. Poly(vinyl chloride) (PVC) was used as a binder of the CNTs. Thus, hybrid-type organic thermoelectric materials containing the NPs were constructed from Pd NPs, CNTs, and PVC. The thermoelectric properties were slightly improved in the three-component films by only mixing the separately-prepared Pd NPs. The NPs of a polymer complex, poly(nickel 1,1,2,2-ethenetetrathiolate) (n-PETT), were also used as a charge carrier transport promoter instead of the Pd NPs to produce n-PETT/CNT/PVC hybrid films. Treatment of the three-component films with methanol produced a high thermoelectric power factor and low thermal conductivity, resulting in a high "apparent" thermoelectric performance ( ZT ˜ 0.3 near room temperature) although the thermal conductivity was measured in the through-plane direction, which is a different direction from that for the electrical conductivity.

  13. 14 CFR Appendix J to Part 141 - Aircraft Type Rating Course, For Other Than an Airline Transport Pilot Certificate

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Aircraft Type Rating Course, For Other Than an Airline Transport Pilot Certificate J Appendix J to Part 141 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SCHOOLS AND OTHER CERTIFICATED AGENCIES PILOT SCHOOLS Pt. 141, App. J Appendix J to Part...

  14. Transportation

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    Here is the decree of the thirtieth of July 1998 relative to road transportation, to trade and brokerage of wastes. It requires to firms which carry out a road transportation as well as to traders and to brokers of wastes to declare their operations to the prefect. The declaration has to be renewed every five years. (O.M.)

  15. Sustained Delivery of Chondroitinase ABC from Hydrogel System

    Directory of Open Access Journals (Sweden)

    Filippo Rossi

    2012-03-01

    Full Text Available In the injured spinal cord, chondroitin sulfate proteoglycans (CSPGs are the principal responsible of axon growth inhibition and they contribute to regenerative failure, promoting glial scar formation. Chondroitinase ABC (chABC is known for being able to digest proteoglycans, thus degrading glial scar and favoring axonal regrowth. However, its classic administration is invasive, infection-prone and clinically problematic. An agarose-carbomer (AC1 hydrogel, already used in SCI repair strategies, was here investigated as a delivery system capable of an effective chABC administration: the material ability to include chABC within its pores and the possibility to be injected into the target tissue were firstly proved. Subsequently, release kinetic and the maintenance of enzymatic activity were positively assessed: AC1 hydrogel was thus confirmed to be a feasible tool for chABC delivery and a promising device for spinal cord injury topic repair strategies.

  16. Copper-transporting P-type ATPases use a unique ion-release pathway

    DEFF Research Database (Denmark)

    Andersson, Magnus; Mattle, Daniel; Sitsel, Oleg

    2014-01-01

    Heavy metals in cells are typically regulated by PIB-type ATPases. The first structure of the class, a Cu(+)-ATPase from Legionella pneumophila (LpCopA), outlined a copper transport pathway across the membrane, which was inferred to be occluded. Here we show by molecular dynamics simulations...... that extracellular water solvated the transmembrane (TM) domain, results indicative of a Cu(+)-release pathway. Furthermore, a new LpCopA crystal structure determined at 2.8-Å resolution, trapped in the preceding E2P state, delineated the same passage, and site-directed-mutagenesis activity assays support...... a functional role for the conduit. The structural similarities between the TM domains of the two conformations suggest that Cu(+)-ATPases couple dephosphorylation and ion extrusion differently than do the well-characterized PII-type ATPases. The ion pathway explains why certain Menkes' and Wilson's disease...

  17. Polymorphism in a second ABC transproter gene located within the class II region of the human major histocompatibility complex

    Energy Technology Data Exchange (ETDEWEB)

    Powis, S.H.; Mockridge, I.; Kelly, A.; Glynne, R.; Beck, S.; Trowsdale, J. (Imperial Cancer Research Fund Labs., London (United Kingdom)); Kerr, L.A. (Guy' s Campus, London (United Kingdom)); Gileadi, U. (Univ. of Oxford (United Kingdom))

    1992-02-15

    Recent studies have identified genes within the major histocompatibility complex (MHC) that may play a role in presentation of antigenic peptides to T cells. The authors have previously described RING4, a gene within the human MHC class II region that has sequence homology with members of the ABC (ATP-binding cassette) transporter superfamily. They now report the nucleotide sequence of RING11, a second ABC transporter gene located approximately 7 kilobases telomeric to RING4. RING11 is {gamma}-interferon inducible, a property shared with other genes involved in antigen presentation. Comparison between the amino acid sequences of RING11 and RING4 reveals strong homology. They propose that they form a heterodimer that transports peptides from the cytoplasm into the endoplasmic reticulum. They have identified two RING11 alleles, which differ in length of their derived protein sequence by 17 amino acids. The more common of these alleles is present in a Caucasoid population at a frequency of 79%.

  18. ABC transporters and multidrug resistance in Aspergillus nidulans

    NARCIS (Netherlands)

    Andrade, A.C.

    2000-01-01

    The term multidrug resistance (MDR) stands for simultaneous cellular resistance to chemically unrelated toxicants and is often associated with overproduction of multidrug-efflux proteins of the A TP- b inding-

  19. Commuters? Exposure to Particulate Matter Air Pollution Is Affected by Mode of Transport, Fuel Type, and Route

    OpenAIRE

    Zuurbier, Moniek; Hoek, Gerard; Oldenwening, Marieke; Lenters, Virissa; Meliefste, Kees; van den Hazel, Peter; Brunekreef, Bert

    2010-01-01

    Background Commuters are exposed to high concentrations of air pollutants, but little quantitative information is currently available on differences in exposure between different modes of transport, routes, and fuel types. Objectives The aim of our study was to assess differences in commuters? exposure to traffic-related air pollution related to transport mode, route, and fuel type. Methods We measured particle number counts (PNCs) and concentrations of PM2.5 (particulate matter ? 2.5 ?m in a...

  20. The ABC of ABC : An analysis of attribute-based credentials in the light of data protection, privacy and identity.

    NARCIS (Netherlands)

    Korenhof, P.E.I.; Koning, Merel; Alpár, Gergely; Hoepman, J.H.; Padullés, Joan Balcells; i Martínez, Agustí Cerrillo; Poch, Miquel Peguera; López, Ismael Peña; de Moner, María José Pifarré; Solana, Mònica Vilasau

    2014-01-01

    Our networked society increasingly needs secure identity sys- tems. The Attribute-based credential (ABC) technology is designed to be privacy-friendlier than contemporary authentication methods, which often suffer from information leakage. So far, however, some of the wider implications of ABC have

  1. The role of transporters on drug therapy

    Directory of Open Access Journals (Sweden)

    . Ngatidjan

    2016-02-01

    Full Text Available ABSTRACT Pharmacodynamical studies showed that most drugs elicit their effects by acting on 3 kinds of protein molecules known as receptors, enzymes or transporters. Although their detail properties had not been explained for decades the roles of transporters in drug kinetics and dynamics has been well understood, even have been applied in the therapy. Transporters are classified into 2 major classes, the solute carriers (SLC and ATP-binding cassette (ABC families. SLC transporters do not possess ATP binding site property as those of ABC transporters. SLC transporters consist of 3 SLC subfamilies i.e. organic cation transporters (OCTs, organic anion transporters (OATs and organic anion transporting polypeptides (OATPs. In contrast, ABC transporters require ATP hydrolysis to transport substrate across cell membrane. Human ABC-transporters consist of ABCA1- 13, ABCB1-11, ABCC1-12, ABCD1-4, ABCE1, ABCF1-3 and ABCG1-8 subfamily. Although the originally funtion of transporter is to transport specific physiological substrate such as nutrient, hormone, cytokines, neurotransmitters and other physiological subtances across cell membrane the specificity is not restricted to each substrate. Drugs and other xenobiotics which have structural similarity to the physiological substrates are recognized and transported by the related transporters. The competition of them on transporters therefore may lead to the occurence of drug-drug interactions (DDI or drugphysiological substrate interaction in the drug-kinetics phase. Many transporters located in the liver, intestinal and renal epithelial cell membranes involve in the transport of endogenous substance or xenobiotics including drugs play important roles as protective barrier. Since transporters also serve as the targets of drug action it is understood that transporters play important role in the pathogenesis of diseases as well as in the drug therapy of diseases.

  2. Structural safety test and analysis of type IP-2 transport packages with bolted lid type and thick steel plate for radioactive waste drums in a NPP

    International Nuclear Information System (INIS)

    Kim, Dong Hak; Seo, Ki Seog; Lee, Sang Jin; Lee, Kyung Ho; Kim, Jeong Mook

    2007-01-01

    If a type IP-2 transport package were to be subjected to a free drop test and a penetration test under the normal conditions of transport, it should prevent a loss or dispersal of the radioactive contents and a more than 20% increase in the maximum radiation level at any external surface of the package. In this paper, we suggested the analytic method to evaluate the structural safety of a type IP-2 transport package using a thick steel plate for a structure part and a bolt for tying a bolt. Using an analysis a loss or disposal of the radioactive contents and a loss of shielding integrity were confirmed for two kinds of type IP-2 transport packages to transport radioactive waste drums from a waste facility to a temporary storage site in a nuclear power plant. Under the free drop condition the maximum average stress at the bolts and the maximum opening displacement of a lid were compared with the tensile stress of a bolt and the steps in a lid, which were made to avoid a streaming radiation in the shielding path, to evaluate a loss or dispersal of radioactive waste contents. Also a loss of shielding integrity was evaluated using the maximum decrease in a shielding thickness. To verify the impact dynamic analysis for free drop test condition and evaluate experimentally the safety of two kinds of type IP-2 transport packages, free drop tests were conducted with various drop directions

  3. Development and potential role of type-2 sodium-glucose transporter inhibitors for management of type 2 diabetes.

    Science.gov (United States)

    Hardman, Timothy Colin; Dubrey, Simon William

    2011-09-01

    There is a recognized need for new treatment options for type 2 diabetes mellitus (T2DM). Recovery of glucose from the glomerular filtrate represents an important mechanism in maintaining glucose homeostasis and represents a novel target for the management of T2DM. Recovery of glucose from the glomerular filtrate is executed principally by the type 2 sodium-glucose cotransporter (SGLT2). Inhibition of SGLT2 promotes glucose excretion and normalizes glycemia in animal models. First reports of specifically designed SGLT2 inhibitors began to appear in the second half of the 1990s. Several candidate SGLT2 inhibitors are currently under development, with four in the later stages of clinical testing. The safety profile of SGLT2 inhibitors is expected to be good, as their target is a highly specific membrane transporter expressed almost exclusively within the renal tubules. One safety concern is that of glycosuria, which could predispose patients to increased urinary tract infections. So far the reported safety profile of SGLT2 inhibitors in clinical studies appears to confirm that the class is well tolerated. Where SGLT2 inhibitors will fit in the current cascade of treatments for T2DM has yet to be established. The expected favorable safety profile and insulin-independent mechanism of action appear to support their use in combination with other antidiabetic drugs. Promotion of glucose excretion introduces the opportunity to clear calories (80-90 g [300-400 calories] of glucose per day) in patients that are generally overweight, and is expected to work synergistically with weight reduction programs. Experience will most likely lead to better understanding of which patients are likely to respond best to SGLT2 inhibitors, and under what circumstances.

  4. Electron transport properties of degenerate n-type GaN prepared by pulsed sputtering

    Science.gov (United States)

    Ueno, Kohei; Fudetani, Taiga; Arakawa, Yasuaki; Kobayashi, Atsushi; Ohta, Jitsuo; Fujioka, Hiroshi

    2017-12-01

    We report a systematic investigation of the transport properties of highly degenerate electrons in Ge-doped and Si-doped GaN epilayers prepared using the pulsed sputtering deposition (PSD) technique. Secondary-ion mass spectrometry and Hall-effect measurements revealed that the doping efficiency of PSD n-type GaN is close to unity at electron concentrations as high as 5.1 × 1020 cm-3. A record low resistivity for n-type GaN of 0.16 mΩ cm was achieved with an electron mobility of 100 cm2 V-1 s-1 at a carrier concentration of 3.9 × 1020 cm-3. We explain this unusually high electron mobility of PSD n-type GaN within the framework of conventional scattering theory by modifying a parameter related to nonparabolicity of the conduction band. The Ge-doped GaN films show a slightly lower electron mobility compared with Si-doped films with the same carrier concentrations, which is likely a consequence of the formation of a small number of compensation centers. The excellent electrical properties presented in this letter clearly demonstrate the striking advantages of the low-temperature PSD technique for growing high-quality and highly conductive n-type GaN.

  5. Transportation

    National Research Council Canada - National Science Library

    Allshouse, Michael; Armstrong, Frederick Henry; Burns, Stephen; Courts, Michael; Denn, Douglas; Fortunato, Paul; Gettings, Daniel; Hansen, David; Hoffman, Douglas; Jones, Robert

    2007-01-01

    .... The ability of the global transportation industry to rapidly move passengers and products from one corner of the globe to another continues to amaze even those wise to the dynamics of such operations...

  6. Bacterial multidrug resistance mediated by a homologue of the human multidrug transporter P-glycoprotein

    NARCIS (Netherlands)

    Konings, WN; Poelarends, GJ

    2002-01-01

    Most ATP-binding cassette (ABC) multidrug transporters known to date are of eukaryotic origin, such as the P-glycoproteins (Pgps) and multidrug resistance-associated proteins (MRPs). Only one well-characterized ABC multidrug transporter, LmrA, is of bacterial origin. On the basis of its structural

  7. ABCA Transporter Gene Expression and Poor Outcome in Epithelial Ovarian Cancer

    DEFF Research Database (Denmark)

    Hedditch, Ellen L; Gao, Bo; Russell, Amanda J

    2014-01-01

    BACKGROUND: ATP-binding cassette (ABC) transporters play various roles in cancer biology and drug resistance, but their association with outcomes in serous epithelial ovarian cancer (EOC) is unknown. METHODS: The relationship between clinical outcomes and ABC transporter gene expression in two in...

  8. Molecular Characterization of CTR-type Copper Transporters in an Oceanic Diatom, Thalassiosira oceanica 1005

    Science.gov (United States)

    Kong, L.; Price, N. M.

    2016-02-01

    Copper is an essential micronutrient for phytoplankton growth because of its role as a redox cofactor in electron transfer proteins in photosynthesis and respiration, and a potentially limiting resource in parts of the open sea. Thalassiosira oceanica 1005 can grow at inorganic copper concentrations varying from 10 fmol/L to 10 nmol/L by regulating copper uptake across plasma membrane. Four putative CTR-type copper transporter genes (ToCTR1, ToCTR2, ToCTR3.1 and ToCTR3.2) were identified by BLASTP search against the T. oceanica genome. Predicted gene models were revised by assembled mRNA sequencing transcripts and updated gene models contained all conserved features of characterized CTR-type copper transporters. ToCTR3.1 and ToCTR3.2 may arise from one another by gene duplication as they shared a sequence similarity of 97.6% with a peptide insertion of 5 amino acids at N-terminus of ToCTR3.1. The expression of ToCTR1, ToCTR2 and ToCTR3.1/3.2 was upregulated in low copper concentrations, but only ToCTR3.1/3.2 showed a significant increase (2.5 fold) in copper-starved cells. Both ToCTR3.1 and ToCTR3.2 restored growth of a yeast double mutant, Saccharomyces cerevisiae ctr1Δctr3Δ, in copper deficient medium. GFP-fused ToCTR expression showed that some ToCTR3.1 localized to the plasma membrane but a large portion was retained in the endoplasmic reticulum. Inefficient targeting of ToCTR3.1 to the yeast outer membrane may explain poorer growth compared to the Saccharomyces native ScCTR1 transformant. Thus, diatom CTR genes encoding CTR-type copper transporters show high-affinity copper uptake and their regulation may enable diatoms to survive in ocean environments containing a wide range of copper concentrations.

  9. A critical role of glutamate transporter type 3 in the learning and memory of mice.

    Science.gov (United States)

    Wang, Zhi; Park, Sang-Hon; Zhao, Huijuan; Peng, Shuling; Zuo, Zhiyi

    2014-10-01

    Hippocampus-dependent learning and memory are associated with trafficking of excitatory amino acid transporter type 3 (EAAT3) to the plasma membrane. To assess whether this trafficking is an intrinsic component of the biochemical responses underlying learning and memory, 7- to 9-week old male EAAT3 knockout mice and CD-1 wild-type mice were subjected to fear conditioning. Their hippocampal CA1 regions, amygdalae and entorhinal cortices were harvested before, or 30 min or 3 h after the fear conditioning stimulation. We found that EAAT3 knockout mice had worse contextual and tone-related learning and memory than did the wild-type mice. The expression of EAAT3, glutamate receptor (GluR)1 and GluR2 in the plasma membrane and of phospho-GluR1 (at Ser 831) and phospho-CaMKII in the hippocampus of the wild-type mice was increased at 30 min after the fear conditioning stimulation. Similar biochemical changes occurred in the amygdala. Fear conditioning also increased the expression of c-Fos and activity-regulated cytoskeleton-associated protein (Arc) in the CA1 regions and of Arc in the entorhinal cortices of the wild-type mice. These biochemical responses were attenuated in the EAAT3 knockout mice. These results suggest that EAAT3 plays a critical role in learning and memory. Our results also provide initial evidence that EAAT3 may have receptor-like functions to participate in the biochemical reactions underlying learning and memory. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Be together, not the same: Spatiotemporal organization of different cilia types generates distinct transport functions

    Science.gov (United States)

    Nawroth, Janna; Guo, Hanliang; Ruby, Edward; Dabiri, John; McFall-Ngai, Margaret; Kanso, Eva

    2016-11-01

    Motile cilia are microscopic, hair-like structures on the cell surface that can sense and propel the extracellular fluid environment. Cilia are often thought to be limited to stereotypic morphologies, beat kinematics and non-discriminatory clearance functions, but we find that the spatiotemporal organization of different cilia types and beat behaviors can generate complex flow patterns and transport functions. Here, we present a case study in the Hawaiian bobtail squid where collective ciliary activity and resulting flow fields help recruit symbiont bacteria to the animal host. In particular, we demonstrate empirically and computationally how the squid's internal cilia act like a microfluidic device that actively filters the water for potential bacterial candidates and also provides a sheltered zone allowing for accumulation of mucus and bacteria into a biofilm. Moreover, in this sheltered zone, different cilia-driven flows enhance diffusion of biochemical signals, which could accelerate specific bacteria-host recognition. These results suggest that studying cilia activity on the population level might reveal a diverse range of biological transport and sensing functions. Moreover, understanding cilia as functional building blocks could inspire the design of ciliated robots and devices.

  11. The development of a type B(U) transport container design in cast and forged stainless steel for the transport of immobilised intermediate level waste

    Energy Technology Data Exchange (ETDEWEB)

    Sievwright, B. [United Kingdom Nirex Ltd, Harwell (United Kingdom); Dixon, P. [RWE NUKEM, Harwell (United Kingdom); Tso, C.F. [Ove Arup and Partners, London (United Kingdom)

    2004-07-01

    United Kingdom Nirex Limited (Nirex) is responsible for providing the United Kingdom with safe, environmentally sound and publicly acceptable options for the long-term management of radioactive materials. This includes intermediate level (ILW) and some low level (LLW) wastes. As part of its role Nirex has defined standards and specifications for the conditioning and packaging of these wastes, and carries out assessments of packaging proposals to ensure compatibility with the requirements for future phases of waste management. In order to facilitate this process and to provide a basis for the production of waste package specifications, Nirex has developed the Phased Disposal Concept, and produced a suite of underpinning safety and performance assessments. It has also undertaken work to assess the compatibility of its waste packaging specifications with other waste management options. The Phased Disposal Concept continues to be developed and updated to incorporate issues arising from dialogue with stakeholders, including members of the public; future changes arising from Government policy, legislation and regulations; information from waste producers, and the results from on-going research and development. One of the documents describing the Phased Disposal Concept is the Generic Transport System Design (GTSD). The GTSD outlines the range of waste packages to be transported and disposed of, and describes the design of the transport system needed to transport wastes from their sites of production or storage to a centralised phased disposal facility site. It also describes a range of re-usable transport containers which could be used to transport those waste packages, which require Type B standards for transport, through the public domain. This paper describes the development to date of such a design of reusable transport container, known as the SWTC-285, the Standard Waste Transport Container (SWTC) with 285 mm of shielding.

  12. Crystal structure of a copper-transporting PIB-type ATPase

    DEFF Research Database (Denmark)

    Gourdon, Pontus Emanuel; Liu, Xiang-Yu; Skjørringe, Tina

    2011-01-01

    Heavy-metal homeostasis and detoxification is crucial for cell viability. P-type ATPases of the class IB (PIB) are essential in these processes, actively extruding heavy metals from the cytoplasm of cells. Here we present the structure of a PIB-ATPase, a Legionella pneumophila CopA Cu......(+)-ATPase, in a copper-free form, as determined by X-ray crystallography at 3.2 Å resolution. The structure indicates a three-stage copper transport pathway involving several conserved residues. A PIB-specific transmembrane helix kinks at a double-glycine motif displaying an amphipathic helix that lines a putative...... copper entry point at the intracellular interface. Comparisons to Ca(2+)-ATPase suggest an ATPase-coupled copper release mechanism from the binding sites in the membrane via an extracellular exit site. The structure also provides a framework to analyse missense mutations in the human ATP7A and ATP7B...

  13. High-impact concrete for fill in US Department of Transportation type shipping containers

    International Nuclear Information System (INIS)

    Greenhalgh, W.O.; Cash, R.J.

    1990-01-01

    This report describes the use of light-weight, high-impact concrete in U.S. Department of Transportation-type shipments. The formulations described are substantially lighter in weight (20 to 50 percent) than construction concrete, but product test specimens generally yield superior impact characteristics. The use of this specialty concrete for container fill, encapsulations, or liquid-waste solidification can be advantageous. Use of the material for container or cask construction has the advantage of lighter weight for easier handling, and the container consistently exhibits better performance on drop tests. High-impact concrete does have the disadvantage of less gamma radiation shielding per volume, but some formulation changes discussed in this report can be used to prepare better shielding concrete. Test characteristics of high-impact concrete are included. 3 refs., 6 figs., 7 tabs

  14. Effect of fiber type and nutritional state on AICAR- and contraction-stimulated glucose transport in rat muscle

    DEFF Research Database (Denmark)

    Ai, Hua; Ihlemann, Jacob; Hellsten, Ylva

    2002-01-01

    )- and alpha(2)-isoforms of AMPK. Expression of both isoforms varied with fiber types, and alpha(2) was highly expressed in nuclei. In conclusion, AICAR-stimulated glucose transport varies with muscle fiber type and nutritional state. AMPK is unlikely to be the sole mediator of contraction-stimulated glucose...

  15. PmSUC3: characterization of a SUT2/SUC3-type sucrose transporter from Plantago major.

    Science.gov (United States)

    Barth, Inga; Meyer, Stefan; Sauer, Norbert

    2003-06-01

    Higher plants possess medium-sized gene families that encode plasma membrane-localized sucrose transporters. For several plant species, it has been shown that at least one of these genes (e.g., AtSUC3 in Arabidopsis and LeSUT2 in tomato) differs from all other family members in several features, such as the length of the open reading frame, the number of introns, and the codon usage bias. For these reasons, and because two of these proteins did not rescue a yeast mutant defective in sucrose utilization, it had been speculated that this subgroup of transporters might have sensor functions. Here, we describe the detailed functional characterization and cellular localization of PmSUC3, the orthologous transporter from the Plantago major transporter family. The PmSUC3 protein is localized in the sieve elements of the Plantago phloem and mediates the energy-dependent transport of sucrose and maltose. In contrast to the situation in solanaceous plants, PmSUC3 is not colocalized with PmSUC2, the source-specific, phloem-loading sucrose transporter of Plantago. Moreover, PmSUC3 also was identified in sieve elements of sink leaves and in several nonphloem cells and tissues. Arguments for and against a potential sensor function for this type of sucrose transporter are presented, and the role of this type of transporter in the regulation of sucrose fluxes is discussed.

  16. Transporter-Guided Delivery of Nanoparticles to Improve Drug Permeation across Cellular Barriers and Drug Exposure to Selective Cell Types

    Directory of Open Access Journals (Sweden)

    Longfa Kou

    2018-01-01

    Full Text Available Targeted nano-drug delivery systems conjugated with specific ligands to target selective cell-surface receptors or transporters could enhance the efficacy of drug delivery and therapy. Transporters are expressed differentially on the cell-surface of different cell types, and also specific transporters are expressed at higher than normal levels in selective cell types under pathological conditions. They also play a key role in intestinal absorption, delivery via non-oral routes (e.g., pulmonary route and nasal route, and transfer across biological barriers (e.g., blood–brain barrier and blood–retinal barrier. As such, the cell-surface transporters represent ideal targets for nano-drug delivery systems to facilitate drug delivery to selective cell types under normal or pathological conditions and also to avoid off-target adverse side effects of the drugs. There is increasing evidence in recent years supporting the utility of cell-surface transporters in the field of nano-drug delivery to increase oral bioavailability, to improve transfer across the blood–brain barrier, and to enhance delivery of therapeutics in a cell-type selective manner in disease states. Here we provide a comprehensive review of recent advancements in this interesting and important area. We also highlight certain key aspects that need to be taken into account for optimal development of transporter-assisted nano-drug delivery systems.

  17. Taurine Transporter Gene Expression in Mononuclear Blood Cells of Type 1 Diabetes Patients.

    Science.gov (United States)

    Napoli, Zaleida; Seghieri, Giuseppe; Bianchi, Loria; Anichini, Roberto; De Bellis, Alessandra; Campesi, Ilaria; Carru, Ciriaco; Occhioni, Stefano; Zinellu, Angelo; Franconi, Flavia

    2016-01-01

    Taurine transporter gene expression (RNA-TauT) has a role in retinal cell function and is modulated in vitro and in vivo by hyperglycemia and/or oxidative stress. This study was aimed at testing whether RNA-TauT gene expression is modified in blood mononuclear peripheral cells (MPCs) of type 1 diabetic patients, is related to plasma markers of oxidative stress or endothelial dysfunction, or, finally, is related to presence of retinopathy. RNA-TauT was measured in MPCs by real-time PCR-analysis in 35 type 1 diabetic patients and in 33 age- and sex-matched controls, additionally measuring plasma and cell taurine and markers of oxidative stress and endothelial dysfunction. RNA-TauT, expressed as 2(-ΔΔCt), was significantly higher in MPCs of type 1 diabetic patients than in controls [median (interquartile range): 1.32(0.31) versus 1.00(0.15); P = 0.01]. In diabetic patients RNA-TauT was related to HbA1c (r = 0.42; P = 0.01) and inversely to plasma homocysteine (r = -0.39; P = 0.02) being additionally significantly higher in MPCs of patients without retinopathy [(n = 22); 1.36(0.34)] compared to those with retinopathy [(n = 13); 1.16(0.20)], independently from HbA1c or diabetes duration. RNA-TauT gene expression is significantly upregulated in MPCs of type 1 diabetes patients and is related to HbA1c levels and inversely to plasma homocysteine. Finally, in diabetes patients, RNA-TauT upregulation seems to be blunted in patients with retinopathy independently of their metabolic control or longer diabetes duration.

  18. Whole-genome survey of the putative ATP-binding cassette transporter family genes in Vitis vinifera.

    Science.gov (United States)

    Çakır, Birsen; Kılıçkaya, Ozan

    2013-01-01

    The ATP-binding cassette (ABC) protein superfamily constitutes one of the largest protein families known in plants. In this report, we performed a complete inventory of ABC protein genes in Vitis vinifera, the whole genome of which has been sequenced. By comparison with ABC protein members of Arabidopsis thaliana, we identified 135 putative ABC proteins with 1 or 2 NBDs in V. vinifera. Of these, 120 encode intrinsic membrane proteins, and 15 encode proteins missing TMDs. V. vinifera ABC proteins can be divided into 13 subfamilies with 79 "full-size," 41 "half-size," and 15 "soluble" putative ABC proteins. The main feature of the Vitis ABC superfamily is the presence of 2 large subfamilies, ABCG (pleiotropic drug resistance and white-brown complex homolog) and ABCC (multidrug resistance-associated protein). We identified orthologs of V. vinifera putative ABC transporters in different species. This work represents the first complete inventory of ABC transporters in V. vinifera. The identification of Vitis ABC transporters and their comparative analysis with the Arabidopsis counterparts revealed a strong conservation between the 2 species. This inventory could help elucidate the biological and physiological functions of these transporters in V. vinifera.

  19. Whole-genome survey of the putative ATP-binding cassette transporter family genes in Vitis vinifera.

    Directory of Open Access Journals (Sweden)

    Birsen Çakır

    Full Text Available The ATP-binding cassette (ABC protein superfamily constitutes one of the largest protein families known in plants. In this report, we performed a complete inventory of ABC protein genes in Vitis vinifera, the whole genome of which has been sequenced. By comparison with ABC protein members of Arabidopsis thaliana, we identified 135 putative ABC proteins with 1 or 2 NBDs in V. vinifera. Of these, 120 encode intrinsic membrane proteins, and 15 encode proteins missing TMDs. V. vinifera ABC proteins can be divided into 13 subfamilies with 79 "full-size," 41 "half-size," and 15 "soluble" putative ABC proteins. The main feature of the Vitis ABC superfamily is the presence of 2 large subfamilies, ABCG (pleiotropic drug resistance and white-brown complex homolog and ABCC (multidrug resistance-associated protein. We identified orthologs of V. vinifera putative ABC transporters in different species. This work represents the first complete inventory of ABC transporters in V. vinifera. The identification of Vitis ABC transporters and their comparative analysis with the Arabidopsis counterparts revealed a strong conservation between the 2 species. This inventory could help elucidate the biological and physiological functions of these transporters in V. vinifera.

  20. Production, regulation and transportation of bacillibactin in bacillus subtilis

    International Nuclear Information System (INIS)

    Raza, W.; Hussain, Q.; Shen, Q.

    2012-01-01

    Bacillus subtilis produces a catecholate type siderophore 'Bacillibactin'. This review focuses on the non-ribosomal synthesis, transport and regulation of bacillibactin. Bacillibactin biosynthetic operon contains five genes (dhbACEBF). The uptake of bacillibactin requires the FeuABC transporter, inner-membrane permease, FepDG and YusV ATPase and an esterase encoding gene, besA and while export required YmfE major facilitator super-family (MFS)-type transporter. Fur is the major iron-controlled transcriptional regulator in B. subtilis, which acts as an iron-dependent repressor of the dhb operon in vivo while an iron-independent repressor in vitro. Knowledge of the Fur regulon will be useful in interpreting other global analysis of transcriptional responses. (author)

  1. Bulk oxides: asymmetry between p-and n-type transport properties

    Science.gov (United States)

    Maignan, Antioine

    2015-03-01

    The thermoelectric power (TEP) of transition metal oxides shows large difference depending on the sign of the charge carriers. In electron-doped oxides, the best TEs in terms of the figure of merit are heavily doped transparent conductors (as doped ZnO). The physics is very similar to that of semiconductors, though the defects chemistry differs: the existence of planar defects created by the doping elements, is far from the random distribution in semiconductors. In contrast the best p-types are layered cobaltites (CdI2 -type layers with edge-shared CoO6 octahedras). The Co cations adopt a low spin state. Both electronic correlations and spin entropy have to be considered to explain the S(T) curve for T 150K, the spin/orbital configurations and the doping level in the generalized Heikes formula are dominating. This description supported by the results obtained for perovskite ruthenates was recently unvalidated for the quadruple perovskite ACu3Ru4O12, showing very different S(T) without S saturation up to ~ 900K. Their Pauli paramagnetism enlights the role of the spins upon thermopower. Similarly, searching for other n-types, interesting TE properties have been found in Ba1.2Mn8O16: the S(T) evidences a charge/orbital ordering in this manganite (vMn = 3.7) coupled to an abrupt change in the unit-cell volume. Ba1.2Mn8O16, although of n-type, exhibits a cst. | S | ~ 92 μV.K-1 for T>400K, explained by the generalized Heikes formula rather used for p-type. This difference with other n-type oxides is related to the Mn3+/Mn4+ magnetism and the contribution of eg orbitals for the transport properties. In this presentation, the richness of the TE properties of metal transition oxides will be emphasized focusing on the important role of the spins.

  2. Modulation of bacterial Type III secretion system by a spermidine transporter dependent signaling pathway.

    Directory of Open Access Journals (Sweden)

    Lian Zhou

    Full Text Available BACKGROUND: Many gram-negative bacterial pathogens employ Type III secretion systems (T3SS to inject effector proteins into host cells in infectious processes. METHODOLOGY/PRINCIPAL FINDINGS: By screening a transposon mutant library of P. aeruginosa, we found that mutation of spuDEFGH, which encode a major spermidine uptake system, abolished the expression of the exsCEBA operon that codes for key T3SS regulators under inducing conditions (low calcium. Whole genome microarray analysis revealed that inactivation of the spermidine uptake system significantly decreased the transcriptional expression of most, if not all, T3SS genes. Consistently, the spermidine uptake mutants showed decreased expression of the T3SS genes in responding to host cell extract and attenuated cytotoxicity. Furthermore, exogenous addition of spermidine to the wild type strain PAO1 enhanced the expression of exsCEBA and also the effector protein genes. CONCLUSION/SIGNIFICANCE: Cumulatively, these data have depicted a novel spermidine transporter-dependent signaling pathway, which appears to play an essential role in modulation of T3SS expression in P. aeruginosa.

  3. Inactivation of the peroxisomal ABCD2 transporter in the mouse leads to late-onset ataxia involving mitochondria, Golgi and endoplasmic reticulum damage

    NARCIS (Netherlands)

    Ferrer, Isidre; Kapfhammer, Josef P.; Hindelang, Colette; Kemp, Stephan; Troffer-Charlier, Nathalie; Broccoli, Vania; Callyzot, Noëlle; Mooyer, Petra; Selhorst, Jacqueline; Vreken, Peter; Wanders, Ronald J. A.; Mandel, Jean Louis; Pujol, Aurora

    2005-01-01

    ATP-binding cassette (ABC) transporters facilitate unidirectional translocation of chemically diverse substances, ranging from peptides to lipids, across cell or organelle membranes. In peroxisomes, a subfamily of four ABC transporters (ABCD1 to ABCD4) has been related to fatty acid transport,

  4. ABC's of Being Smart: I Can "C" Clearly Now

    Science.gov (United States)

    Foster, Joanne

    2011-01-01

    In this paper, the author focuses on C of the ABC's of being smart. She continues to categorize the points for readers. These categories include the following: (1) being; (2) doing; and (3) stretching.

  5. Compilation of accelerated bridge construction (ABC) bridges : final report.

    Science.gov (United States)

    2016-01-01

    Development of accelerated bridge construction (ABC) technologies has been occurring across the country, many times in : isolation. Although FHWA and others have worked to facilitate communication between these efforts, there was not a : comprehensiv...

  6. Lenalidomide modulates gene expression in human ABC-DLBCL cells by regulating IKAROS interaction with an intronic control region of SPIB.

    Science.gov (United States)

    Solomon, Lauren A; Batista, Carolina R; DeKoter, Rodney P

    2017-12-01

    Activated B-cell diffuse large B-cell lymphoma (ABC-DLBCL) is associated with a poor prognosis compared with other DLBCL types and therefore represents a top priority for developing novel therapies. Lenalidomide, an immunomodulatory drug in trials for treatment of ABC-DLBCL, targets the transcription factor IKAROS for degradation by the cereblon E3 ubiquitin ligase complex. In this study, we investigated whether the gene encoding the transcription factor SPI-B is a target of IKAROS. Using cultured ABC-DLBCL cell lines, we found that high levels of SPI-B expression conferred resistance to lenalidomide. Lenalidomide treatment of ABC-DLBCL cells resulted in downregulation of SPIB at the level of transcription. SPIB was regulated directly by IKAROS through a binding site located in the first intron of the gene. Inhibition of IKAROS binding using CRISPR/Cas9-mediated transcriptional repression downregulated endogenous SPIB transcription. Finally, ectopic expression of IKAROS protected SPIB from downregulation. These results show that the mechanism of action of lenalidomide in ABC-DLBCL cells involves downregulation of SPIB transcription by cereblon-induced degradation of IKAROS. These results have implications for the design of synthetic lethal therapy for the treatment of ABC-DLBCL. Copyright © 2017 ISEH – Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.

  7. Application of the ABC analysis in management of food inventory

    OpenAIRE

    Radek Toušek

    2009-01-01

    The article is focused on managing stock inventory with help of the ABC method. The theory is explained on an actual company dealing with retail grocery distribution within the south bohemian region. The ABC method is applied on 4,405 inventory items regarding their 2008 year turnover. Results of the analysis are processed into a system plan to reduce the asset liability and decrease the stock inventory while maintaining the requested quality of logistic services.

  8. Polymorphism of the dopamine transporter type 1 gene modifies the treatment response in Parkinson's disease.

    Science.gov (United States)

    Moreau, Caroline; Meguig, Sayah; Corvol, Jean-Christophe; Labreuche, Julien; Vasseur, Francis; Duhamel, Alain; Delval, Arnaud; Bardyn, Thomas; Devedjian, Jean-Christophe; Rouaix, Nathalie; Petyt, Gregory; Brefel-Courbon, Christine; Ory-Magne, Fabienne; Guehl, Dominique; Eusebio, Alexandre; Fraix, Valérie; Saulnier, Pierre-Jean; Lagha-Boukbiza, Ouhaid; Durif, Frank; Faighel, Mirela; Giordana, Caroline; Drapier, Sophie; Maltête, David; Tranchant, Christine; Houeto, Jean-Luc; Debû, Bettina; Azulay, Jean-Philippe; Tison, François; Destée, Alain; Vidailhet, Marie; Rascol, Olivier; Dujardin, Kathy; Defebvre, Luc; Bordet, Régis; Sablonnière, Bernard; Devos, David

    2015-05-01

    After more than 50 years of treating Parkinson's disease with l-DOPA, there are still no guidelines on setting the optimal dose for a given patient. The dopamine transporter type 1, now known as solute carrier family 6 (neurotransmitter transporter), member 3 (SLC6A3) is the most powerful determinant of dopamine neurotransmission and might therefore influence the treatment response. We recently demonstrated that methylphenidate (a dopamine transporter inhibitor) is effective in patients with Parkinson's disease with motor and gait disorders. The objective of the present study was to