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Sample records for atp-binding cassette abc

  1. Functional analysis of the ATP-binding cassette (ABC transporter gene family of Tribolium castaneum

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    Broehan Gunnar

    2013-01-01

    Full Text Available Abstract Background The ATP-binding cassette (ABC transporters belong to a large superfamily of proteins that have important physiological functions in all living organisms. Most are integral membrane proteins that transport a broad spectrum of substrates across lipid membranes. In insects, ABC transporters are of special interest because of their role in insecticide resistance. Results We have identified 73 ABC transporter genes in the genome of T. castaneum, which group into eight subfamilies (ABCA-H. This coleopteran ABC family is significantly larger than those reported for insects in other taxonomic groups. Phylogenetic analysis revealed that this increase is due to gene expansion within a single clade of subfamily ABCC. We performed an RNA interference (RNAi screen to study the function of ABC transporters during development. In ten cases, injection of double-stranded RNA (dsRNA into larvae caused developmental phenotypes, which included growth arrest and localized melanization, eye pigmentation defects, abnormal cuticle formation, egg-laying and egg-hatching defects, and mortality due to abortive molting and desiccation. Some of the ABC transporters we studied in closer detail to examine their role in lipid, ecdysteroid and eye pigment transport. Conclusions The results from our study provide new insights into the physiological function of ABC transporters in T. castaneum, and may help to establish new target sites for insect control.

  2. 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

  3. A Survey of the ATP-Binding Cassette (ABC Gene Superfamily in the Salmon Louse (Lepeophtheirus salmonis.

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    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.

  4. AztD, a Periplasmic Zinc Metallochaperone to an ATP-binding Cassette (ABC) Transporter System in Paracoccus denitrificans.

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    Handali, Melody; Roychowdhury, Hridindu; Neupane, Durga P; Yukl, Erik T

    2015-12-11

    Bacterial ATP-binding cassette (ABC) transporters of transition metals are essential for acquisition of necessary elements from the environment. A large number of Gram-negative bacteria, including human pathogens, have a fourth conserved gene of unknown function adjacent to the canonical permease, ATPase, and solute-binding protein (SBP) genes of the AztABC zinc transporter system. To assess the function of this putative accessory factor (AztD) from Paracoccus denitrificans, we have analyzed its transcriptional regulation, metal binding properties, and interaction with the SBP (AztC). Transcription of the aztD gene is significantly up-regulated under conditions of zinc starvation. Recombinantly expressed AztD purifies with slightly substoichiometric zinc from the periplasm of Escherichia coli and is capable of binding up to three zinc ions with high affinity. Size exclusion chromatography and a simple intrinsic fluorescence assay were used to determine that AztD as isolated is able to transfer bound zinc nearly quantitatively to apo-AztC. Transfer occurs through a direct, associative mechanism that prevents loss of metal to the solvent. These results indicate that AztD is a zinc chaperone to AztC and likely functions to maintain zinc homeostasis through interaction with the AztABC system. This work extends our understanding of periplasmic zinc trafficking and the function of chaperones in this process.

  5. Transmembrane gate movements in the type II ATP-binding cassette (ABC) importer BtuCD-F during nucleotide cycle.

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    Joseph, Benesh; Jeschke, Gunnar; Goetz, Birke A; Locher, Kaspar P; Bordignon, Enrica

    2011-11-25

    ATP-binding cassette (ABC) transporters are ubiquitous integral membrane proteins that translocate substrates across cell membranes. The alternating access of their transmembrane domains to opposite sides of the membrane powered by the closure and reopening of the nucleotide binding domains is proposed to drive the translocation events. Despite clear structural similarities, evidence for considerable mechanistic diversity starts to accumulate within the importers subfamily. We present here a detailed study of the gating mechanism of a type II ABC importer, the BtuCD-F vitamin B(12) importer from Escherichia coli, elucidated by EPR spectroscopy. Distance changes at key positions in the translocation gates in the nucleotide-free, ATP- and ADP-bound conformations of the transporter were measured in detergent micelles and liposomes. The translocation gates of the BtuCD-F complex undergo conformational changes in line with a "two-state" alternating access model. We provide the first direct evidence that binding of ATP drives the gates to an inward-facing conformation, in contrast to type I importers specific for maltose, molybdate, or methionine. Following ATP hydrolysis, the translocation gates restore to an apo-like conformation. In the presence of ATP, an excess of vitamin B(12) promotes the reopening of the gates toward the periplasm and the dislodgment of BtuF from the transporter. The EPR data allow a productive translocation cycle of the vitamin B(12) transporter to be modeled.

  6. Whole-transcriptome survey of the putative ATP-binding cassette (ABC) transporter family genes in the latex-producing laticifers of Hevea brasiliensis.

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    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.

  7. Whole-transcriptome survey of the putative ATP-binding cassette (ABC transporter family genes in the latex-producing laticifers of Hevea brasiliensis.

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    Nie Zhiyi

    Full Text Available 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.

  8. Genome-wide identification of ATP-binding cassette (ABC) transporters and their roles in response to polycyclic aromatic hydrocarbons (PAHs) in the copepod Paracyclopina nana.

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    Jeong, Chang-Bum; Kim, Duck-Hyun; Kang, Hye-Min; Lee, Young Hwan; Kim, Hui-Su; Kim, Il-Chan; Lee, Jae-Seong

    2017-02-01

    The ATP-binding cassette (ABC) protein superfamily is one of the largest gene families and is highly conserved in all domains. The ABC proteins play roles in several biological processes, including multi-xenobiotic resistance (MXR), by functioning as transporters in the cellular membrane. They also mediate the cellular efflux of a wide range of substrates against concentration gradients. In this study, 37 ABC genes belonging to eight distinct subfamilies were identified in the marine copepod Paracyclopina nana and annotated based on a phylogenetic analysis. Also, the functions of P-glycoproteins (P-gp) and multidrug resistance-associated proteins (MRPs), conferring MXR, were verified using fluorescent substrates and specific inhibitors. The activities of MXR-mediated ABC proteins and their transcriptional level were examined in response to polyaromatic hydrocarbons (PAHs), main components of the water-accommodated fraction. This study increases the understanding of the protective role of MXR in response to PAHs over the comparative evolution of ABC gene families.

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

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

    2013-01-01

    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

  10. Atovaquone and quinine anti-malarials inhibit ATP binding cassette transporter activity

    NARCIS (Netherlands)

    Rijpma, S.R.; Heuvel, J.J.; Velden, M. van der; Sauerwein, R.W.; Russel, F.G.; Koenderink, J.B.

    2014-01-01

    BACKGROUND: Therapeutic blood plasma concentrations of anti-malarial drugs are essential for successful treatment. Pharmacokinetics of pharmaceutical compounds are dependent of adsorption, distribution, metabolism, and excretion. ATP binding cassette (ABC) transport proteins are particularly involve

  11. Regulatory pathways for ATP-binding cassette transport proteins in kidney proximal tubules

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    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 elabor

  12. Host response transcriptional profiling reveals extracellular components and ABC (ATP-binding cassette transporters gene enrichment in typhoid fever-infected Nigerian children

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    Resau James H

    2011-09-01

    bacterial invasion. Distinct gene expression profiles can also be obtained from acute vs. convalescent phase during typhoid fever infection. We found novel down-regulation of ABC (ATP-binding cassette transporters genes such as ABCA7, ABCC5, and ABCD4 and ATPase activity as the highest enriched pathway. Conclusions We identified unique extracellular components and ABC transporters gene enrichments in typhoid fever-infected Nigerian children, which have never been reported. These enriched gene clusters may represent novel targeted pathways to improve diagnostic, prognostic, therapeutic and next-generation vaccine strategies for typhoid fever in Africa.

  13. Crystal structure of ATP-binding subunit of an ABC transporter from Geobacillus kaustophilus.

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    Manjula, M; Pampa, K J; Kumar, S M; Mukherjee, S; Kunishima, N; Rangappa, K S; Lokanath, N K

    2015-03-27

    The ATP binding cassette (ABC) transporters, represent one of the largest superfamilies of primary transporters, which are very essential for various biological functions. The crystal structure of ATP-binding subunit of an ABC transporter from Geobacillus kaustophilus has been determined at 1.77 Å resolution. The crystal structure revealed that the protomer has two thick arms, (arm I and II), which resemble 'L' shape. The ATP-binding pocket is located close to the end of arm I. ATP molecule is docked into the active site of the protein. The dimeric crystal structure of ATP-binding subunit of ABC transporter from G. kaustophilus has been compared with the previously reported crystal structure of ATP-binding subunit of ABC transporter from Salmonella typhimurium.

  14. Multidrug transport by ATP binding cassette transporters : a proposed two-cylinder engine mechanism

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    van Veen, HW; Higgins, CF; Konings, WN

    2001-01-01

    The elevated expression of ATP binding cassette (ABC) multidrug transporters in multidrug-resistant cells interferes with the drug-based control of cancers and infectious pathogenic microorganisms. Multidrug transporters interact directly with the drug substrates. This review summarizes current insi

  15. Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast

    DEFF Research Database (Denmark)

    Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D.;

    2014-01-01

    Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been i...

  16. ATP-Binding Cassette Systems of Brucella

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    Dominic C. Jenner

    2009-01-01

    Full Text Available Brucellosis is a prevalent zoonotic disease and is endemic in the Middle East, South America, and other areas of the world. In this study, complete inventories of putative functional ABC systems of five Brucella species have been compiled and compared. ABC systems of Brucella melitensis 16M, Brucella abortus 9-941, Brucella canis RM6/66, Brucella suis 1330, and Brucella ovis 63/290 were identified and aligned. High numbers of ABC systems, particularly nutrient importers, were found in all Brucella species. However, differences in the total numbers of ABC systems were identified (B. melitensis, 79; B. suis, 72; B. abortus 64; B. canis, 74; B. ovis, 59 as well as specific differences in the functional ABC systems of the Brucella species. Since B. ovis is not known to cause human brucellosis, functional ABC systems absent in the B. ovis genome may represent virulence factors in human brucellosis.

  17. Localization of the ATP-binding cassette (ABC transport proteins PfMRP1, PfMRP2, and PfMDR5 at the Plasmodium falciparum plasma membrane

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    Luty Adrian JF

    2009-08-01

    Full Text Available Abstract Background The spread of drug resistance has been a major obstacle to the control of malaria. The mechanisms underlying drug resistance in malaria seem to be complex and multigenic. The current literature on multiple drug resistance against anti-malarials has documented PfMDR1, an ATP-binding cassette (ABC protein, as an important determinant of resistance. In the Plasmodium falciparum genome, there are several ABC transporters some of which could be putative drug transporting proteins. In order to understand the molecular mechanisms underlying drug resistance, characterization of these transporters is essential. The aim of this study was to characterize and localize putative ABC transporters. Methods In the plasmoDB database, 16 members of the P. falciparum ABC family can be identified, 11 of which are putative transport proteins. A phylogenetic analysis of the aligned NBDs of the PfABC genes was performed. Antibodies against PfMRP1 (PfABCC1, PfMRP2 (PfABCC2, and PfMDR5 (PfABCB5 were generated, affinity purified and used in immunocytochemistry to localize the proteins in the asexual stages of the parasite. Results The ABC family members of P. falciparum were categorized into subfamilies. The ABC B subfamily was the largest and contained seven members. Other family members that could be involved in drug transport are PfABCC1, PfABCC2, PfABCG1, and PfABCI3. The expression and localization of three ABC transport proteins was determined. PfMRP1, PfMRP2, and PfMDR5 are localized to the plasma membrane in all asexual stages of the parasite. Conclusion In conclusion, 11 of the 16 ABC proteins in the P. falciparum genome are putative transport proteins, some of which might be involved in drug resistance. Moreover, it was demonstrated that three of these proteins are expressed on the parasite's plasma membrane.

  18. The saci_2123 gene of the hyperthermoacidophile Sulfolobus acidocaldarius encodes an ATP-binding cassette multidrug transporter

    NARCIS (Netherlands)

    Yang, Nuan; Driessen, Arnold J. M.

    2015-01-01

    Multidrug resistance (MDR) transporters are capable of secreting structurally and functionally unrelated toxic compounds from the cell. Among this group are ATP-binding cassette (ABC) transporters. These membrane proteins are typically arranged as either hetero- or homo-dimers of ABC half-transporte

  19. Mutating the Conserved Q-loop Glutamine 1291 Selectively Disrupts Adenylate Kinase-dependent Channel Gating of the ATP-binding Cassette (ABC) Adenylate Kinase Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and Reduces Channel Function in Primary Human Airway Epithelia.

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    Dong, Qian; Ernst, Sarah E; Ostedgaard, Lynda S; Shah, Viral S; Ver Heul, Amanda R; Welsh, Michael J; Randak, Christoph O

    2015-05-29

    The ATP-binding cassette (ABC) transporter cystic fibrosis transmembrane conductance regulator (CFTR) and two other non-membrane-bound ABC proteins, Rad50 and a structural maintenance of chromosome (SMC) protein, exhibit adenylate kinase activity in the presence of physiologic concentrations of ATP and AMP or ADP (ATP + AMP ⇆ 2 ADP). The crystal structure of the nucleotide-binding domain of an SMC protein in complex with the adenylate kinase bisubstrate inhibitor P(1),P(5)-di(adenosine-5') pentaphosphate (Ap5A) suggests that AMP binds to the conserved Q-loop glutamine during the adenylate kinase reaction. Therefore, we hypothesized that mutating the corresponding residue in CFTR, Gln-1291, selectively disrupts adenylate kinase-dependent channel gating at physiologic nucleotide concentrations. We found that substituting Gln-1291 with bulky side-chain amino acids abolished the effects of Ap5A, AMP, and adenosine 5'-monophosphoramidate on CFTR channel function. 8-Azidoadenosine 5'-monophosphate photolabeling of the AMP-binding site and adenylate kinase activity were disrupted in Q1291F CFTR. The Gln-1291 mutations did not alter the potency of ATP at stimulating current or ATP-dependent gating when ATP was the only nucleotide present. However, when physiologic concentrations of ADP and AMP were added, adenylate kinase-deficient Q1291F channels opened significantly less than wild type. Consistent with this result, we found that Q1291F CFTR displayed significantly reduced Cl(-) channel function in well differentiated primary human airway epithelia. These results indicate that a highly conserved residue of an ABC transporter plays an important role in adenylate kinase-dependent CFTR gating. Furthermore, the results suggest that adenylate kinase activity is important for normal CFTR channel function in airway epithelia.

  20. ROLE OF ATP BINDING CASSETTE SUB-FAMILY MEMBER 2 (ABCG2) IN MOUSE EMBRYONIC STEM CELL DEVELOPMENT.

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    ATP binding cassette sub-family member 2 (ABCG2), is a member of the ABC transporter superfamily and a principal xenobiotic transporter. ABCG2 is also highly expressed in certain stem cell populations where it is thought to be related to stem cell plasticity, although the role o...

  1. ATP-binding cassette transporters in tumor endothelial cells and resistance to metronomic chemotherapy.

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    Hida, Kyoko; Kikuchi, Hiroshi; Maishi, Nako; Hida, Yasuhiro

    2017-02-16

    Drug resistance is a major problem in anticancer therapy. ATP-binding cassette (ABC) transporters have a role in the multidrug resistance. A new regimen of chemotherapy has been proposed, called "metronomic chemotherapy". Metronomic chemotherapy is the frequent, regular administration of drug doses designed to maintain low, but active, concentrations of chemotherapeutic drugs over prolonged periods of time, without causing serious toxicities. Metronomic chemotherapy regimens were developed to optimize the antitumor efficacy of agents that target the tumor vasculature instead of tumor cells, and to reduce toxicity of antineoplastic drugs [1]. Nevertheless, recent studies revealed that ABC transporters are expressed at a higher level in the endothelium in the tumor. To avoid resistance to metronomic anti-angiogenic chemotherapy, ABC transporter inhibition of tumor endothelial cells may be a promising strategy. In this mini-review, we discuss the possible mechanism of resistance to metronomic chemotherapy from the viewpoint of tumor endothelial cell biology, focusing on ABC transporters.

  2. Receptor-transporter interactions of canonical ATP-binding cassette import systems in prokaryotes.

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    Schneider, Erwin; Eckey, Viola; Weidlich, Daniela; Wiesemann, Nicole; Vahedi-Faridi, Ardeshir; Thaben, Paul; Saenger, Wolfram

    2012-04-01

    ATP-binding cassette (ABC) transport systems mediate the translocation of solutes across biological membranes at the expense of ATP. They share a common modular architecture comprising two pore-forming transmembrane domains and two nucleotide binding domains. In prokaryotes, ABC transporters are involved in the uptake of a large variety of chemicals, including nutrients, osmoprotectants and signal molecules. In pathogenic bacteria, some ABC importers are virulence factors. Canonical ABC import systems require an additional component, a substrate-specific receptor or binding protein for function. Interaction of the liganded receptor with extracytoplasmic loop regions of the transmembrane domains initiate the transport cycle. In this review we summarize the current knowledge on receptor-transporter interplay provided by crystal structures as well as by biochemical and biophysical means. In particular, we focus on the maltose/maltodextrin transporter of enterobacteria and the transporters for positively charged amino acids from the thermophile Geobacillus stearothermophilus and Salmonella enterica serovar Typhimurium.

  3. Transport in technicolor: mapping ATP-binding cassette transporters in sea urchin embryos.

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    Gökirmak, Tufan; Shipp, Lauren E; Campanale, Joseph P; Nicklisch, Sascha C T; Hamdoun, Amro

    2014-09-01

    One quarter of eukaryotic genes encode membrane proteins. These include nearly 1,000 transporters that translocate nutrients, signaling molecules, and xenobiotics across membranes. While it is well appreciated that membrane transport is critical for development, the specific roles of many transporters have remained cryptic, in part because of their abundance and the diversity of their substrates. Multidrug resistance ATP-binding cassette (ABC) efflux transporters are one example of cryptic membrane proteins. Although most organisms utilize these ABC transporters during embryonic development, many of these transporters have broad substrate specificity, and their developmental functions remain incompletely understood. Here, we review advances in our understanding of ABC transporters in sea urchin embryos, and methods developed to spatially and temporally map these proteins. These studies reveal that multifunctional transporters are required for signaling, homeostasis, and protection of the embryo, and shed light on how they are integrated into ancestral developmental pathways recapitulated in disease.

  4. Polymorphisms in ATP-binding cassette transporter genes and interaction with diet and life style factors in relation to colorectal cancer in a Danish prospective case-cohort study

    DEFF Research Database (Denmark)

    Kopp, Tine Iskov; Andersen, Vibeke; Tjonneland, Anne;

    2015-01-01

    The ATP-binding cassette (ABC) transporter family transports various molecules across the enterocytes in the gut protecting the intestine against potentially harmful substances. Moreover, ABC transporters are involved in mucosal immune defence through interaction with cytokines. The study aimed...

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

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    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 (...

  6. The role of ATP-binding cassette transporter A2 in childhood acute lymphoblastic leukemia multidrug resistance

    OpenAIRE

    Aberuyi, N; Rahgozar, S; Moafi, A

    2014-01-01

    Acute lymphoblastic leukemia (ALL) is one of the most prevalent hematologic malignancies in children. Although the cure rate of ALL has improved over the past decades, the most important reason for ALL treatment failure is multidrug resistance (MDR) phenomenon. The current study aims to explain the mechanisms involved in multidrug resistance of childhood ALL, and introduces ATP-binding cassette transporterA2 (ABCA2) as an ABC transporter gene which may have a high impact on MDR. Benefiting fr...

  7. Protection against chemotherapy-induced alopecia: targeting ATP-binding cassette transporters in the hair follicle?

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    Haslam, Iain S; Pitre, Aaron; Schuetz, John D; Paus, Ralf

    2013-11-01

    Currently, efficacious treatments for chemotherapy-induced alopecia (hair loss) are lacking, and incidences of permanent hair loss following high-dose chemotherapy are on the increase. In this article, we describe mechanisms by which the pharmacological defense status of the hair follicle might be enhanced, thereby reducing the accumulation of cytotoxic cancer drugs and preventing or reducing hair loss and damage. We believe this could be achieved via the selective increase in ATP-binding cassette (ABC) transporter expression within the hair follicle epithelium, following application of topical agonists for regulatory nuclear receptors. Clinical application would require the development of hair follicle-targeted formulations, potentially utilizing nanoparticle technology. This novel approach has the potential to yield entirely new therapeutic options for the treatment and management of chemotherapy-induced alopecia, providing significant psychological and physical benefit to cancer patients.

  8. The role of ATP-binding cassette transporters in neuro-inflammation: relevance for bioactive lipids

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    Gijs eKooij

    2012-04-01

    Full Text Available ATP-binding cassette (ABC transporters are highly expressed by brain endothelial cells that form the blood-brain barrier (BBB. These efflux pumps play an important role in maintaining brain homeostasis as they actively hinder the entry of unwanted blood-derived compounds into the central nervous system (CNS. Consequently, their high activity at the BBB has been a major hurdle for the treatment of several brain diseases, as they prevent numerous drugs to reach their site of action within the brain. Importantly, recent data indicate that endogenous substrates for ABC transporters may include inflammatory mediators, such as prostaglandins, leukotrienes, cytokines, chemokines and bioactive lipids, suggesting a potential role for ABC transporters in immunological responses, and more specifically in inflammatory brain disorders, such as multiple sclerosis (MS. In this review, we will give a comprehensive overview of recent findings that illustrate this novel role for ABC transporters in neuro-inflammatory processes. Moreover, we will provide first insights into underlying mechanisms and focus on the importance for bioactive lipids, in particular platelet-activating factor (PAF, herein. A thorough understanding of these events may form the basis for the development for selective treatment modalities to dampen the neuro-inflammatory attack in MS and thereby reducing tissue damage.

  9. Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast.

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    Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D; Andersen, Tonni G; Pomorski, Thomas G

    2014-12-01

    Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been implicated in sterol uptake, but key features of their activity remain to be elucidated. Here, we apply fluorescent cholesterol (NBD-cholesterol) to monitor sterol uptake under anaerobic and aerobic conditions in two fungal species, Candida glabrata (Cg) and Saccharomyces cerevisiae (Sc). We found that in both fungal species, ABC transporter-dependent uptake of cholesterol under anaerobic conditions and in mutants lacking HEM1 gene is promoted in the presence of the serum protein albumin that is able to bind the sterol molecule. Furthermore, the C. glabrata ABC transporter CgAus1p expressed in S. cerevisiae requires the presence of serum or albumin for efficient cholesterol uptake. These results suggest that albumin can serve as sterol donor in ABC transporter-dependent sterol uptake, a process potentially important for growth of C. glabrata inside infected humans.

  10. The saci_2123 gene of the hyperthermoacidophile Sulfolobus acidocaldarius encodes an ATP-binding cassette multidrug transporter.

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    Yang, Nuan; Driessen, Arnold J M

    2015-01-01

    Multidrug resistance (MDR) transporters are capable of secreting structurally and functionally unrelated toxic compounds from the cell. Among this group are ATP-binding cassette (ABC) transporters. These membrane proteins are typically arranged as either hetero- or homo-dimers of ABC half-transporters with each subunit consisting of a membrane domain fused at the C-terminus to an ATP-binding domain, or as full transporters in which the two subunits are fused into a single polypeptide. The saci_2123 gene of the thermoacidophilic archaeon Sulfolobus acidocaldarius is the only gene in the genome that encodes an ATP-binding cassette half-transporter, while a homologous gene is present in the genomes of S. solfataricus, S. tokodaii and S islandicus. Saci_2123 shares homology with well-characterized bacterial and mammalian MDR transporters. The saci_2132 gene is up-regulated when cells are exposed to drugs. A deletion mutant of saci_2132 was found to be more vulnerable to a set of toxic compounds, including detergents, antibiotics and uncouplers as compared to the wild-type strain, while the drug resistance could be restored through the plasmid-based expression of saci_2132. These data demonstrate that Saci_2132 is an archaeal ABC-MDR transporter and therefore it was termed Smr1 (Sulfolobus multidrug resistance transporter 1).

  11. ATP-Binding Cassette Transporters Modulate Both Coelenterazine- and D-Luciferin-Based Bioluminescence Imaging

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    Ruimin Huang

    2011-05-01

    Full Text Available Bioluminescence imaging (BLI of luciferase reporters provides a cost-effective and sensitive means to image biological processes. However, transport of luciferase substrates across the cell membrane does affect BLI readout intensity from intact living cells. To investigate the effect of ATP-binding cassette (ABC transporters on BLI readout, we generated click beetle (cLuc, firefly (fLuc, Renilla (rLuc, and Gaussia (gLuc luciferase HEK-293 reporter cells that overexpressed different ABC transporters (ABCB1, ABCC1, and ABCG2. In vitro studies showed a significant BLI intensity decrease in intact cells compared to cell lysates, when ABCG2 was overexpressed in HEK-293/cLuc, fLuc, and rLuc cells. Selective ABC transporter inhibitors were also applied. Inhibition of ABCG2 activity increased the BLI intensity more than two-fold in HEK-293/cLuc, fLuc, and rLuc cells; inhibition of ABCB1 elevated the BLI intensity two-fold only in HEK-293/rLuc cells. BLI of xenografts derived from HEK-293/ABC transporter/luciferase reporter cells confirmed the results of inhibitor treatment in vivo. These findings demonstrate that coelenterazine-based rLuc-BLI intensity can be modulated by ABCB1 and ABCG2. ABCG2 modulates d-luciferin-based BLI in a luciferase type–independent manner. Little ABC transporter effect on gLuc-BLI intensity is observed because a large fraction of gLuc is secreted. The expression level of ABC transporters is one key factor affecting BLI intensity, and this may be particularly important in luciferase-based applications in stem cell research.

  12. 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

  13. Secretion of natural and synthetic toxic compounds from filamentous fungi by membrane transporters of the ATP-binding cassette and major facilitator superfamily

    NARCIS (Netherlands)

    Stergiopoulos, I.; Zwiers, L.H.; Waard, De M.A.

    2002-01-01

    This review provides an overview of members of the ATP-binding cassette (ABC) and major facilitator superfamily (MFS) of transporters identified in filamentous fungi. The most common function of these membrane proteins is to provide protection against natural toxic compounds present in the environme

  14. An ATP Binding Cassette Transporter Mediates the Uptake of α-(1,6)-Linked Dietary Oligosaccharides in Bifidobacterium and Correlates with Competitive Growth on These Substrates

    DEFF Research Database (Denmark)

    Hansen, Morten Ejby; Fredslund, Folmer; Andersen, Joakim Mark

    2016-01-01

    and lactobacilli in the human gut. Here we show that the solute binding protein (BlG16BP) associated with an ATP binding cassette (ABC) transporter from the probiotic Bifidobacterium animalis subsp. lactis Bl-04 binds -(1,6)-linked glucosides and galactosides of varying size, linkage, and monosaccharide...

  15. Control of Mycosphaerella graminicola on wheat seedlings by medical drugs known to modulate the activity of ATP-binding cassette transporters

    NARCIS (Netherlands)

    Roohparvar, R.; Huser, A.; Zwiers, L.H.; Waard, de M.A.

    2007-01-01

    Medical drugs known to modulate the activity of human ATP-binding cassette (ABC) transporter proteins (modulators) were tested for the ability to potentiate the activity of the azole fungicide cyproconazole against in vitro growth of Mycosphaerella graminicola and to control disease development due

  16. 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

  17. 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.

  18. 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.

  19. Repositioning of Tyrosine Kinase Inhibitors as Antagonists of ATP-Binding Cassette Transporters in Anticancer Drug Resistance

    Directory of Open Access Journals (Sweden)

    Yi-Jun Wang

    2014-09-01

    Full Text Available The phenomenon of multidrug resistance (MDR has attenuated the efficacy of anticancer drugs and the possibility of successful cancer chemotherapy. ATP-binding cassette (ABC transporters play an essential role in mediating MDR in cancer cells by increasing efflux of drugs from cancer cells, hence reducing the intracellular accumulation of chemotherapeutic drugs. Interestingly, small-molecule tyrosine kinase inhibitors (TKIs, such as AST1306, lapatinib, linsitinib, masitinib, motesanib, nilotinib, telatinib and WHI-P154, have been found to have the capability to overcome anticancer drug resistance by inhibiting ABC transporters in recent years. This review will focus on some of the latest and clinical developments with ABC transporters, TKIs and anticancer drug resistance.

  20. Localization of the ATP-binding cassette (ABC) transport proteins PfMRP1, PfMRP2, and PfMDR5 at the Plasmodium falciparum plasma membrane.

    NARCIS (Netherlands)

    Kavishe, R.A.; Heuvel, J.M.W. van den; Vegte-Bolmer, M. van de; Luty, A.J.; Russel, F.G.M.; Koenderink, J.B.

    2009-01-01

    BACKGROUND: The spread of drug resistance has been a major obstacle to the control of malaria. The mechanisms underlying drug resistance in malaria seem to be complex and multigenic. The current literature on multiple drug resistance against anti-malarials has documented PfMDR1, an ATP-binding casse

  1. Small substrate transport and mechanism of a molybdate ATP binding cassette transporter in a lipid environment.

    Science.gov (United States)

    Rice, Austin J; Harrison, Alistair; Alvarez, Frances J D; Davidson, Amy L; Pinkett, Heather W

    2014-05-23

    Embedded in the plasma membrane of all bacteria, ATP binding cassette (ABC) importers facilitate the uptake of several vital nutrients and cofactors. The ABC transporter, MolBC-A, imports molybdate by passing substrate from the binding protein MolA to a membrane-spanning translocation pathway of MolB. To understand the mechanism of transport in the biological membrane as a whole, the effects of the lipid bilayer on transport needed to be addressed. Continuous wave-electron paramagnetic resonance and in vivo molybdate uptake studies were used to test the impact of the lipid environment on the mechanism and function of MolBC-A. Working with the bacterium Haemophilus influenzae, we found that MolBC-A functions as a low affinity molybdate transporter in its native environment. In periods of high extracellular molybdate concentration, H. influenzae makes use of parallel molybdate transport systems (MolBC-A and ModBC-A) to take up a greater amount of molybdate than a strain with ModBC-A alone. In addition, the movement of the translocation pathway in response to nucleotide binding and hydrolysis in a lipid environment is conserved when compared with in-detergent analysis. However, electron paramagnetic resonance spectroscopy indicates that a lipid environment restricts the flexibility of the MolBC translocation pathway. By combining continuous wave-electron paramagnetic resonance spectroscopy and substrate uptake studies, we reveal details of molybdate transport and the logistics of uptake systems that employ multiple transporters for the same substrate, offering insight into the mechanisms of nutrient uptake in bacteria.

  2. Structure, function, and evolution of bacterial ATP-binding cassette systems

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, A.L.; Dassa, E.; Orelle, C.; Chen, J. (Purdue)

    2010-07-27

    The ATP-binding cassette (ABC) systems constitute one of the largest superfamilies of paralogous sequences. All ABC systems share a highly conserved ATP-hydrolyzing domain or protein (the ABC; also referred to as a nucleotide-binding domain [NBD]) that is unequivocally characterized by three short sequence motifs (Fig. 1): these are the Walker A and Walker B motifs, indicative of the presence of a nucleotide-binding site, and the signature motif, unique to ABC proteins, located upstream of the Walker B motif (426). Other motifs diagnostic of ABC proteins are also indicated in Fig. 1. The biological significance of these motifs is discussed in Structure, Function, and Dynamics of the ABC. ABC systems are widespread among living organisms and have been detected in all genera of the three kingdoms of life, with remarkable conservation in the primary sequence of the cassette and in the organization of the constitutive domains or subunits (203, 420). ABC systems couple the energy of ATP hydrolysis to an impressively large variety of essential biological phenomena, comprising not only transmembrane (TM) transport, for which they are best known, but also several non-transport-related processes, such as translation elongation (62) and DNA repair (174). Although ABC systems deserve much attention because they are involved in severe human inherited diseases (107), they were first discovered and characterized in detail in prokaryotes, as early as the 1970s (13, 148, 238, 468). The most extensively analyzed systems were the high-affinity histidine and maltose uptake systems of Salmonella enterica serovar Typhimurium and Escherichia coli. Over 2 decades ago, after the completion of the nucleotide sequences encoding these transporters in the respective laboratories of Giovanna Ames and Maurice Hofnung, Hiroshi Nikaido and colleagues noticed that the two systems displayed a global similarity in the nature of their components and, moreover, that the primary sequences of MalK and

  3. Evaluation of the role of ATP-binding cassette transporters as a defence mechanism against temephos in populations of Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Estelita Pereira Lima

    2014-11-01

    Full Text Available The role of ATP-binding cassette (ABC transporters in the efflux of the insecticide, temephos, was assessed in the larvae of Aedes aegypti. Bioassays were conducted using mosquito populations that were either susceptible or resistant to temephos by exposure to insecticide alone or in combination with sublethal doses of the ABC transporter inhibitor, verapamil (30, 35 and 40 μM. The best result in the series was obtained with the addition of verapamil (40 μM, which led to a 2x increase in the toxicity of temephos, suggesting that ABC transporters may be partially involved in conferring resistance to the populations evaluated.

  4. Genome-wide identification and characterization of ATP-binding cassette transporters in the silkworm, Bombyx mori

    Directory of Open Access Journals (Sweden)

    Zhang Jianzhen

    2011-10-01

    Full Text Available Abstract Background The ATP-binding cassette (ABC transporter superfamily is the largest transporter gene family responsible for transporting specific molecules across lipid membranes in all living organisms. In insects, ABC transporters not only have important functions in molecule transport, but also play roles in insecticide resistance, metabolism and development. Results From the genome of the silkworm, Bombyx mori, we have identified 51 putative ABC genes which are classified into eight subfamilies (A-H by phylogenetic analysis. Gene duplication is very evident in the ABCC and ABCG subfamilies, whereas gene numbers and structures are well conserved in the ABCD, ABCE, ABCF, and ABCH subfamilies. Microarray analysis revealed that expression of 32 silkworm ABC genes can be detected in at least one tissue during different developmental stages, and the expression patterns of some of them were confirmed by quantitative real-time PCR. A large number of ABC genes were highly expressed in the testis compared to other tissues. One of the ABCG genes, BmABC002712, was exclusively and abundantly expressed in the Malpighian tubule implying that BmABC002712 plays a tissue-specific role. At least 5 ABCG genes, including BmABC005226, BmABC005203, BmABC005202, BmABC010555, and BmABC010557, were preferentially expressed in the midgut, showing similar developmental expression profiles to those of 20-hydroxyecdysone (20E-response genes. 20E treatment induced the expression of these ABCG genes in the midgut and RNA interference-mediated knockdown of USP, a component of the 20E receptor, decreased their expression, indicating that these midgut-specific ABCG genes are 20E-responsive. Conclusion In this study, a genome-wide analysis of the silkworm ABC transporters has been conducted. A comparison of ABC transporters from 5 insect species provides an overview of this vital gene superfamily in insects. Moreover, tissue- and stage-specific expression data of the

  5. Computational characterization of TTHA0379: A potential glycerophosphocholine binding protein of Ugp ATP-binding cassette transporter.

    Science.gov (United States)

    Chandravanshi, Monika; Gogoi, Prerana; Kanaujia, Shankar Prasad

    2016-11-05

    For the de novo biosynthesis of phospholipids, byproducts such as sn-glycerol-3-phosphate (G3P) and glycerophosphocholine (GPC) of glycerophospholipid metabolic pathway are imported inside the cell by an ATP-binding cassette (ABC) transporter known as UgpABCE. Of which, UgpA and UgpE constitutes the transmembrane domains (TMDs), UgpC forms the dimer of ATP-hydrolyzing component and UgpB is the periplasmic substrate binding protein. Structurally, UgpABCE transporter displays similarity to the maltose ABC transporter of Escherichia coli; thus, has been grouped into the CUT1 (Carbohydrate Uptake Transporter-1) family of bacterial ABC transporters. Being a member of CUT1 family, several Ugp (Uptake glycerol phosphate) protein sequences in biological database(s) exhibit sequence and structure similarity to sugar ABC transporters and have been annotated as sugar binding proteins; one of such proteins is TTHA0379 from Thermus thermophilus HB8. Here, in this study, we used computational method(s) to distinguish UgpB and sugar binding proteins based on their primary and tertiary structure features. A comprehensive analysis of these proteins indicates that they are evolutionarily related to each other having common conserved features at their primary and tertiary structure levels. However, they display differences at their active sites owing to the dissimilarity in their ligand preferences. In addition, phylogenetic analysis of TTHA0379 along with UgpB and sugar binding proteins reveals that both the groups of proteins forms two distinct clades and TTHA0379 groups with UgpB proteins. Furthermore, analysis of the ligand binding pocket shows that all the essential features of glycerophosphocholine binding protein i.e. UgpB, are conserved in TTHA0379 as well. Combining these features, here, we designate TTHA0379 to be a GPC binding protein.

  6. ATP-binding cassette transporters and sterol O-acyltransferases interact at membrane microdomains to modulate sterol uptake and esterification.

    Science.gov (United States)

    Gulati, Sonia; Balderes, Dina; Kim, Christine; Guo, Zhongmin A; Wilcox, Lisa; Area-Gomez, Estela; Snider, Jamie; Wolinski, Heimo; Stagljar, Igor; Granato, Juliana T; Ruggles, Kelly V; DeGiorgis, Joseph A; Kohlwein, Sepp D; Schon, Eric A; Sturley, Stephen L

    2015-11-01

    A key component of eukaryotic lipid homeostasis is the esterification of sterols with fatty acids by sterol O-acyltransferases (SOATs). The esterification reactions are allosterically activated by their sterol substrates, the majority of which accumulate at the plasma membrane. We demonstrate that in yeast, sterol transport from the plasma membrane to the site of esterification is associated with the physical interaction of the major SOAT, acyl-coenzyme A:cholesterol acyltransferase (ACAT)-related enzyme (Are)2p, with 2 plasma membrane ATP-binding cassette (ABC) transporters: Aus1p and Pdr11p. Are2p, Aus1p, and Pdr11p, unlike the minor acyltransferase, Are1p, colocalize to sterol and sphingolipid-enriched, detergent-resistant microdomains (DRMs). Deletion of either ABC transporter results in Are2p relocalization to detergent-soluble membrane domains and a significant decrease (53-36%) in esterification of exogenous sterol. Similarly, in murine tissues, the SOAT1/Acat1 enzyme and activity localize to DRMs. This subcellular localization is diminished upon deletion of murine ABC transporters, such as Abcg1, which itself is DRM associated. We propose that the close proximity of sterol esterification and transport proteins to each other combined with their residence in lipid-enriched membrane microdomains facilitates rapid, high-capacity sterol transport and esterification, obviating any requirement for soluble intermediary proteins.

  7. High glucose decreases the expression of ATP-binding cassette transporter G1 in human vascular smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    Jiahong Xue; Zuyi Yuan; Yue Wu; Yan Zhao; Zhaofei Wan

    2008-01-01

    Objective:ATP-binding cassette transporters(ABC) A1 and G1 play an important role in mediating cholesterol efflux and preventing macrophage foam cell formation. In this study, we examined the regulation of ABC transporters by high glucose in human vascular smooth muscle cells(VSMCs), the other precursor of foam cells. Methods:Incubation of human VSMCs with D-ghicose(5 to 30 mM) for 1 to 7 days in the presence or absence of antioxidant and nuclear factor(NF)-kB inhibitors, the expressions of ABCA1 and ABCG1 were analyzed by real time PCR and Western blotting. Results:High glucose decreased ABCG1 mRNA and protein expression in cultured VSMCs, whereas the expression of ABCA1 was not significantly decreased. Down-regulation of ABCG1 mRNA expression by high glucose was abolished by antioxidant N-acetyl-L-cysteine(NAC) and NF-kB inhibitors, BAY 11-7085 and tosyl-phenylalanine chloromethyl-ketone(TPCK). Conclusion:High glucose suppresses the expression of ABCG1 in VSMCs, which is the possible mechanism of VSMC derived foam cell transformation.

  8. The ATP-binding cassette transporter-2 (ABCA2) regulates esterification of plasma membrane cholesterol by modulation of sphingolipid metabolism.

    Science.gov (United States)

    Davis, Warren

    2014-01-01

    The ATP-binding cassette transporters are a large family (~48 genes divided into seven families A-G) of proteins that utilize the energy of ATP-hydrolysis to pump substrates across lipid bilayers against a concentration gradient. The ABC "A" subfamily is comprised of 13 members and transport sterols, phospholipids and bile acids. ABCA2 is the most abundant ABC transporter in human and rodent brain with highest expression in oligodendrocytes, although it is also expressed in neurons. Several groups have studied a possible connection between ABCA2 and Alzheimer's disease as well as early atherosclerosis. ABCA2 expression levels have been associated with changes in cholesterol and sphingolipid metabolism. In this paper, we hypothesized that ABCA2 expression level may regulate esterification of plasma membrane-derived cholesterol by modulation of sphingolipid metabolism. ABCA2 overexpression in N2a neuroblastoma cells was associated with an altered bilayer distribution of the sphingolipid ceramide that inhibited acylCoA:cholesterol acyltransferase (ACAT) activity and cholesterol esterification. In contrast, depletion of endogenous ABCA2 in the rat schwannoma cell line D6P2T increased esterification of plasma membrane cholesterol following treatment with exogenous bacterial sphingomyelinase. These findings suggest that control of ABCA2 expression level may be a key locus of regulation for esterification of plasma membrane-derived cholesterol through modulation of sphingolipid metabolism.

  9. Purification, crystallization and preliminary X-ray diffraction analysis of the putative ABC transporter ATP-binding protein from Thermotoga maritima

    Science.gov (United States)

    Ethayathulla, Abdul S.; Bessho, Yoshitaka; Shinkai, Akeo; Padmanabhan, Balasundaram; Singh, Tej P.; Kaur, Punit; Yokoyama, Shigeyuki

    2008-01-01

    Adenosine triphosphate (ATP) binding cassette transporters (ABC transporters) are ATP hydrolysis-dependent transmembrane transporters. Here, the overproduction, purification and crystallization of the putative ABC transporter ATP-binding protein TM0222 from Thermotoga maritima are reported. The protein was crystallized in the hexagonal space group P6422, with unit-cell parameters a = b = 148.49, c = 106.96 Å, γ = 120.0°. Assuming the presence of two molecules in the asymmetric unit, the calculated V M is 2.84 Å3 Da−1, which corresponds to a solvent content of 56.6%. A three-wavelength MAD data set was collected to 2.3 Å resolution from SeMet-substituted TM0222 crystals. Data sets were collected on the BL38B1 beamline at SPring-8, Japan. PMID:18540059

  10. Genetic Analysis of the Mode of Interplay between an ATPase Subunit and Membrane Subunits of the Lipoprotein-Releasing ATP-Binding Cassette Transporter LolCDE†

    OpenAIRE

    Ito, Yasuko; Matsuzawa, Hitomi; Matsuyama, Shin-ichi; Narita, Shin-ichiro; Tokuda, Hajime

    2006-01-01

    The LolCDE complex, an ATP-binding cassette (ABC) transporter, releases lipoproteins from the inner membrane, thereby initiating lipoprotein sorting to the outer membrane of Escherichia coli. The LolCDE complex is composed of two copies of an ATPase subunit, LolD, and one copy each of integral membrane subunits LolC and LolE. LolD hydrolyzes ATP on the cytoplasmic side of the inner membrane, while LolC and/or LolE recognize and release lipoproteins anchored to the periplasmic leaflet of the i...

  11. Molecular cloning and functional characterization of an ATP-binding cassette transporter OtrC from Streptomyces rimosus

    Directory of Open Access Journals (Sweden)

    Yu Lan

    2012-08-01

    Full Text Available Abstract Background The otrC gene of Streptomyces rimosus was previously annotated as an oxytetracycline (OTC resistance protein. However, the amino acid sequence analysis of OtrC shows that it is a putative ATP-binding cassette (ABC transporter with multidrug resistance function. To our knowledge, none of the ABC transporters in S. rimosus have yet been characterized. In this study, we aimed to characterize the multidrug exporter function of OtrC and evaluate its relevancy to OTC production. Results In order to investigate OtrC’s function, otrC is cloned and expressed in E. coli The exporter function of OtrC was identified by ATPase activity determination and ethidium bromide efflux assays. Also, the susceptibilities of OtrC-overexpressing cells to several structurally unrelated drugs were compared with those of OtrC-non-expressing cells by minimal inhibitory concentration (MIC assays, indicating that OtrC functions as a drug exporter with a broad range of drug specificities. The OTC production was enhanced by 1.6-fold in M4018 (P = 0.000877 and 1.4-fold in SR16 (P = 0.00973 duplication mutants, while it decreased to 80% in disruption mutants (P = 0.0182 and 0.0124 in M4018 and SR16, respectively. Conclusions The results suggest that OtrC is an ABC transporter with multidrug resistance function, and plays an important role in self-protection by drug efflux mechanisms. This is the first report of such a protein in S. rimosus, and otrC could be a valuable target for genetic manipulation to improve the production of industrial antibiotics.

  12. Selective and ATP-dependent translocation of peptides by the homodimeric ATP binding cassette transporter TAP-like (ABCB9)

    NARCIS (Netherlands)

    Wolters, Justina Clarinda; Abele, Rupert; Tampé, Robert

    2005-01-01

    The transporter associated with antigen processing (TAP)-like (TAPL, ABCB9) belongs to the ATP-binding cassette transporter family, which translocates a vast variety of solutes across membranes. The function of this half-size transporter has not yet been determined. Here, we show that TAPL forms a h

  13. The ATP-binding Cassette Transporter OsABCG15 is Required for Anther Development and Pollen Fertility in Rice

    Institute of Scientific and Technical Information of China (English)

    Bai-Xiao Niu; Fu-Rong He; Ming He; Ding Ren; Le-Tian Chen; Yao-Guang Liu

    2013-01-01

    Plant male reproductive development is a complex biological process,but the underlying mechanism is not well understood.Here,we characterized a rice (Oryza sativa L.) male sterile mutant.Based on mapbased cloning and sequence analysis,we identified a 1,459-bp deletion in an adenosine triphosphate (ATP)-binding cassette (ABC) transporter gene,OsABCG15,causing abnormal anthers and male sterility.Therefore,we named this mutant osabcg15.Expression analysis showed that OsABCG15 is expressed specifically in developmental anthers from stage 8 (meiosis Ⅱ stage) to stage 10 (late microspore stage).Two genes CYP704B2 and WDA1,involved in the biosynthesis of very-long-chain fatty acids for the establishment of the anther cuticle and pollen exine,were downregulated in osabcg15 mutant,suggesting that OsABCG15 may play a key function in the processes related to sporopollenin biosynthesis or sporopollenin transfer from tapetal cells to anther locules.Consistently,histological analysis showed that osabcg15 mutants developed obvious abnormality in postmeiotic tapetum degeneration,leading to rapid degredation of young microspores.The results suggest that OsABCG15 plays a critical role in exine formation and pollen development,similar to the homologous gene of AtABCG26 in Arabidopsis.This work is helpful to understand the regulatory network in rice anther development.

  14. ATP-Binding Cassette Genes Genotype and Expression: A Potential Association with Pancreatic Cancer Development and Chemoresistance?

    Directory of Open Access Journals (Sweden)

    Li Pang

    2014-01-01

    Full Text Available Genetic polymorphisms in ABC (ATP-binding cassette transporter genes are associated with differential responses to chemotherapy in various cancers including pancreatic cancer. In this study, four SNPs in the ABCB1, ABCC1, and ABCG2 genes were investigated in normal and pancreatic cancerous specimens. The expression of the three transporters was also analyzed. The TT genotypes of G2677T and C3435T in ABCB1 gene were associated with lower risk of developing pancreatic cancer (P=0.013, OR = 0.35 and P=0.015, OR = 0.29, resp.. To our knowledge, this is the first report of the common polymorphisms in the ABCB1 gene affecting the genetic risk of developing pancreatic cancer. Moreover, the expression of ABCB1 in 2677TT and 3435TT carriers was lower compared to the wild-type homozygotes and heterozygotes. A cell viability assay, using standard pancreatic cancer cell lines, revealed that the ABCB1 2677TT-3455TT haplotype was more sensitive than the other haplotypes to gemcitabine. Conclusion. Polymorphisms in ABCB1 G2677T and G3435T were associated with differential susceptibility to pancreatic cancer and may predict responses to chemotherapy.

  15. Suppression of c-Myc is involved in multi-walled carbon nanotubes' down-regulation of ATP-binding cassette transporters in human colon adenocarcinoma cells.

    Science.gov (United States)

    Wang, Zhaojing; Xu, Yonghong; Meng, Xiangning; Watari, Fumio; Liu, Hudan; Chen, Xiao

    2015-01-01

    Over-expression of ATP-binding cassette (ABC) transporters, a large family of integral membrane proteins that decrease cellular drug uptake and accumulation by active extrusion, is one of the major causes of cancer multi-drug resistance (MDR) that frequently leads to failure of chemotherapy. Carbon nanotubes (CNTs)-based drug delivery devices hold great promise in enhancing the efficacy of cancer chemotherapy. However, CNTs' effects on the ABC transporters remain under-investigated. In this study, we found that multiwalled carbon nanotubes (MWCNTs) reduced transport activity and expression of ABC transporters including ABCB1/Pgp and ABCC4/MRP4 in human colon adenocarcinoma Caco-2 cells. Proto-oncogene c-Myc, which directly regulates ABC gene expression, was concurrently decreased in MWCNT-treated cells and forced over-expression of c-Myc reversed MWCNTs' inhibitory effects on ABCB1 and ABCC4 expression. MWCNT-cell membrane interaction and cell membrane oxidative damage were observed. However, antioxidants such as vitamin C, β-mecaptoethanol and dimethylthiourea failed to antagonize MWCNTs' down-regulation of ABC transporters. These data suggest that MWCNTs may act on c-Myc, but not through oxidative stress, to down-regulate ABC transporter expression. Our findings thus shed light on CNTs' novel cellular effects that may be utilized to develop CNTs-based drug delivery devices to overcome ABC transporter-mediated cancer chemoresistance.

  16. Effects of silencing the ATP-binding cassette protein E1 gene by electroporation on the proliferation and migration of EC109 human esophageal cancer cells.

    Science.gov (United States)

    Li, Xiao-Rui; Yang, Liu-Zhong; Huo, Xiao-Qing; Wang, Ying; Yang, Qing-Hui; Zhang, Qing-Qin

    2015-07-01

    In the present study, the gene expression of ATP-binding cassette protein E1 (ABCE1) in the EC109 human esophageal cancer cell line was silenced using electroporation to examine the effect if the ABCE1 gene on the growth migration and cell cycle of cancer cells. The small interference (si)RNA sequence of ABCE1 was designed and synthesized to transfect the EC109 cells by electroporation. The mRNA and protein expression levels of ABCE1 were then detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The analysis of the cell cycle and apoptosis was performed using flow cytometry. The effect of silencing the ABCE1 gene on the proliferation, migration and invasive ability of the EC109 human esophageal cancer cells were assessed using a Cell counting kit-8 (CCK-8) and with proliferation, wound-healing and cell invasion assays. The mRNA and protein expression levels of ABCE1 were significantly lower in the experimental group compared with the control group (Pmigration capacity of the cells in the experimental group was significantly decreased (Pmigration in esophageal cancer and silencing the ABCE1 gene by electroporation can significantly reduce the proliferation, invasion and migration capacity of EC109 cells in vitro.

  17. The role of ATP-binding cassette transporter A2 in childhood acute lymphoblastic leukemia multidrug resistance

    Science.gov (United States)

    Aberuyi, N; Rahgozar, S; Moafi, A

    2014-01-01

    Acute lymphoblastic leukemia (ALL) is one of the most prevalent hematologic malignancies in children. Although the cure rate of ALL has improved over the past decades, the most important reason for ALL treatment failure is multidrug resistance (MDR) phenomenon. The current study aims to explain the mechanisms involved in multidrug resistance of childhood ALL, and introduces ATP-binding cassette transporterA2 (ABCA2) as an ABC transporter gene which may have a high impact on MDR. Benefiting from articles published inreputable journals from1994 to date and experiments newly performed by our group, a comprehensive review is written about ABCA2 and its role in MDR regarding childhood ALL. ABCA2 transports drugs from the cytoplasm into the lysosomal compartment, where they may become degraded and exported from the cell. The aforementioned mechanism may contribute to MDR. It has been reported that ABCA2 may induce resistance to mitoxantrone, estrogen derivatives and estramustine. It is resistant to the aforementioned compounds. Furthermore, the overexpression ofABCA2 in methotrexate, vinblastine and/or doxorubicin treated Jurkat cells are observed in several publications. The recent study of our group showsthatthe overexpression ofABCA2 gene in children with ALL increases the risk of MDR by 15 times. ABCA2 is the second identified member of the ABCA; ABC transporters' subfamily. ABCA2 gene expression profile is suggested to be an unfavorable prognostic factor in ALL treatment. Better understanding of the MDR mechanisms and the factors involved may improve the therapeutic outcome of ALL by modifying the treatment protocols. PMID:25254091

  18. The role of ATP-binding cassette transporter A2 in childhood acute lymphoblastic leukemia multidrug resistance.

    Science.gov (United States)

    Aberuyi, N; Rahgozar, S; Moafi, A

    2014-01-01

    Acute lymphoblastic leukemia (ALL) is one of the most prevalent hematologic malignancies in children. Although the cure rate of ALL has improved over the past decades, the most important reason for ALL treatment failure is multidrug resistance (MDR) phenomenon. The current study aims to explain the mechanisms involved in multidrug resistance of childhood ALL, and introduces ATP-binding cassette transporterA2 (ABCA2) as an ABC transporter gene which may have a high impact on MDR. Benefiting from articles published inreputable journals from1994 to date and experiments newly performed by our group, a comprehensive review is written about ABCA2 and its role in MDR regarding childhood ALL. ABCA2 transports drugs from the cytoplasm into the lysosomal compartment, where they may become degraded and exported from the cell. The aforementioned mechanism may contribute to MDR. It has been reported that ABCA2 may induce resistance to mitoxantrone, estrogen derivatives and estramustine. It is resistant to the aforementioned compounds. Furthermore, the overexpression ofABCA2 in methotrexate, vinblastine and/or doxorubicin treated Jurkat cells are observed in several publications. The recent study of our group showsthatthe overexpression ofABCA2 gene in children with ALL increases the risk of MDR by 15 times. ABCA2 is the second identified member of the ABCA; ABC transporters' subfamily. ABCA2 gene expression profile is suggested to be an unfavorable prognostic factor in ALL treatment. Better understanding of the MDR mechanisms and the factors involved may improve the therapeutic outcome of ALL by modifying the treatment protocols.

  19. Molecular Characterization of LjABCG1, an ATP-Binding Cassette Protein in Lotus japonicus.

    Directory of Open Access Journals (Sweden)

    Akifumi Sugiyama

    Full Text Available LjABCG1, a full-size ABCG subfamily of ATP-binding cassette proteins of a model legume, Lotus japonicus, was reported as a gene highly expressed during the early stages of nodulation, but have not been characterized in detail. In this study we showed that the induction of LjABCG1 expression was remarkable by methyl jasmonate treatment, and reporter gene experiments indicated that LjABCG1 was strongly expressed in the nodule parenchyma and cell layers adjacent to the root vascular tissue toward the nodule. LjABCG1 was suggested to be localized at the plasma membrane based on the fractionation of microsomal membranes as well as separation via aqueous two-phase partitioning. The physiological functions of LjABCG1 in symbiosis and pathogenesis were analyzed in homologous and heterologous systems. LjABCG1 knock-down L. japonicus plants did not show clear phenotypic differences in nodule formation, and not in defense against Pseudomonas syringae, either. In contrast, when LjABCG1 was expressed in the Arabidopsis pdr8-1 mutant, the penetration frequency of Phytophthora infestans, a potato late blight pathogen, was significantly reduced in LjABCG1/pdr8-1 than in pdr8-1 plants. This finding indicated that LjABCG1, at least partially, complemented the phenotype of pdr8 in Arabidopsis, suggesting the multiple roles of this protein in plant-microbe interactions.

  20. A conserved mitochondrial ATP-binding cassette transporter exports glutathione polysulfide for cytosolic metal cofactor assembly.

    Science.gov (United States)

    Schaedler, Theresia A; Thornton, Jeremy D; Kruse, Inga; Schwarzländer, Markus; Meyer, Andreas J; van Veen, Hendrik W; Balk, Janneke

    2014-08-22

    An ATP-binding cassette transporter located in the inner mitochondrial membrane is involved in iron-sulfur cluster and molybdenum cofactor assembly in the cytosol, but the transported substrate is unknown. ATM3 (ABCB25) from Arabidopsis thaliana and its functional orthologue Atm1 from Saccharomyces cerevisiae were expressed in Lactococcus lactis and studied in inside-out membrane vesicles and in purified form. Both proteins selectively transported glutathione disulfide (GSSG) but not reduced glutathione in agreement with a 3-fold stimulation of ATPase activity by GSSG. By contrast, Fe(2+) alone or in combination with glutathione did not stimulate ATPase activity. Arabidopsis atm3 mutants were hypersensitive to an inhibitor of glutathione biosynthesis and accumulated GSSG in the mitochondria. The growth phenotype of atm3-1 was strongly enhanced by depletion of the mitochondrion-localized, GSH-dependent persulfide oxygenase ETHE1, suggesting that the physiological substrate of ATM3 contains persulfide in addition to glutathione. Consistent with this idea, a transportomics approach using mass spectrometry showed that glutathione trisulfide (GS-S-SG) was transported by Atm1. We propose that mitochondria export glutathione polysulfide, containing glutathione and persulfide, for iron-sulfur cluster assembly in the cytosol.

  1. Caveolin-1 and ATP binding cassette transporter A1 and G1-mediated cholesterol efflux.

    Science.gov (United States)

    Wang, Faqi; Gu, Hong-mei; Zhang, Da-wei

    2014-01-01

    Atherosclerosis is one major cause of cardiovascular diseases, the leading cause of death in industrialized countries. Reverse cholesterol transport (RCT) is thought to be one primary pathway to protect against atherosclerosis. The first and rate-limiting step of RCT is ATP-binding cassette transport A1 (ABCA1) and ABCG1-mediated cholesterol efflux from the cells. Recently, caveolin-1 (CAV1), a scaffolding protein that organizes and concentrates certain caveolin-interacting signaling molecules and receptors within caveolae membranes, has been shown to regulate ABCA1 and ABCG1-mediated cholesterol efflux probably via interacting with them. In the present review, we summarize the current knowledge and views on the regulatory role of CAV1 on the cholesterol homeostasis with emphasis on the association of CAV1 with ABCA1 and ABCG1. We conclude that the dominance of the positive regulation by CAV1 on the ABCA1 and ABCG1-mediated cholesterol efflux is depending on the species, cell types, as well as the levels of CAV1 expression.

  2. ATP结合盒蛋白E1在真核生物中的作用%Role of ATP-binding cassette protein E1 in eukaryote

    Institute of Scientific and Technical Information of China (English)

    尤锋; 李燕

    2012-01-01

    ATP结合盒(ATP-binding cassette,ABC)蛋白超家族是真核生物进化过程中最为保守的一类蛋白.ABCE1是ABC超家族中E亚家族的唯一成员,除可抑制哺乳动物核糖核酸酶L外,还参与真核生物蛋白合成的翻译起始、终止及核糖体循环,并有可能成为新的抗肿瘤靶点.本文对ABCE1的基本生物学特性及其生物学作用作一介绍.%ATP-binding cassette ( ABC) proteins are one of the most conserved protein families in eukaryote evolution. ABCE1 is the only member in ABC E subfamily. It was found that ABCE1, a ribonuclease L inhibitor in mammals, participates in the protein translation's initiation, termination and ribosome recycling of eukaryote, and may become a new antitumor target. This article reviews the basic biological characteristics and functions of ABCE1.

  3. ATP-binding cassette subfamily B member 1 (ABCB1) and subfamily C member 10 (ABCC10) are not primary resistance factors for cabazitaxel

    Institute of Scientific and Technical Information of China (English)

    Rishil J Kathawala; Yi-Jun Wang; Suneet Shukla; Yun-Kai Zhang; Saeed Alqahtani; Amal Kaddoumi; Suresh V Ambudkar; Charles R Ashby Jr; Zhe-Sheng Chen

    2015-01-01

    Introduction:ATP-binding cassette subfamily B member 1 (ABCB1) and subfamily C member 10 (ABCC10) proteins are efflux transporters that couple the energy derived from ATP hydrolysis to the translocation of toxic substances and chemotherapeutic drugs out of cells. Cabazitaxel is a novel taxane that differs from paclitaxel by its lower affinity for ATP-binding cassette (ABC) transporters. Methods:We determined the effects of cabazitaxel, a novel tubulin-binding taxane, and paclitaxel on paclitaxel-resistant, ABCB1-overexpressing KB-C2 and LLC-MDR1-WT cells and paclitaxel-resistant, ABCC10-overexpressing HEK293/ABCC10 cells by calculating the degree of drug resistance and measuring ATPase activity of the ABCB1 transporter. Results:Decreased resistance to cabazitaxel compared with paclitaxel was observed in KB-C2, LLC-MDR1-WT, and HEK293/ABCC10 cells. Moreover, cabazitaxel had low efficacy, whereas paclitaxel had high efficacy in stimulating the ATPase activity of ABCB1, indicating a direct interaction of both drugs with the transporter. Conclusion:ABCB1 and ABCC10 are not primary resistance factors for cabazitaxel compared with paclitaxel, suggesting that cabazitaxel may have a low affinity for these efflux transporters.

  4. Oxidized LDL upregulated ATP binding cassette transporter-1 in THP-1 macrophages

    Institute of Scientific and Technical Information of China (English)

    Chao-ke TANG; Guang-hui YI; Jun-hao YANG; Lu-shan LIU; Zuo WANG; Chang-geng RUAN; Yong-zong YANG

    2004-01-01

    AIM: To study the effect of oxidized low density lipoprotein (ox-LDL) on ATP binding cassette transporter A1 (ABCA1) in THP-1 macrophages. METHODS: After exposing the cultured THP-1 macrophages to ox-LDL for different periods, cholesterol efflux was determined by FJ-2107P type liquid scintillator. ABCA1 mRNA and protein level were determined by reverse trancriptase-polymerase chain reaction (RT-PCR) and Western blot, respectively.The cholesterol level in THP-1 macrophage foam cells was detected by high performance liquid chromatography.RESULTS: ox-LDL elevated AB CA1 in both protein and mRNA levels and increased apolipoprotein (apo) A-I-mediated cholesterol efflux in a time- and dose-dependent manner. 22(R)-hydroxyeholesterol and 9-cis-retinoic acid did significantly increase cholesterol efflux in THP-1 macrophage foam cells (P<0.05), respectively. Both of them further promoted cholesterol efflux (P<0.01). As expected, liver X receptor (LXR) agonist decreased content of esterified cholesterol in the macrophage foam cells compared with control, whereas only a slight decrease of free cholesterol was observed. LXR activity was slightly increased by oxidized LDL by 12 % at 12 h compared with 6 h.However, LXR activity was increased about 1.8 times at 24 h, and oxidized LDL further increased LXR activity by about 2.6 times at 48 h. CONCLUSION: ABCA1 gene expression was markedly increased in cholesterol-loaded cells as a result of activation of LXR/RXR. ABCA1 plays an important role in the homeostasis of cholesterol in the macrophages.

  5. Molecular Events Involved in a Single Cycle of Ligand Transfer from an ATP Binding Cassette Transporter, LolCDE, to a Molecular Chaperone, LolA*

    OpenAIRE

    Taniguchi, Naohiro; Tokuda, Hajime

    2008-01-01

    An ATP binding cassette transporter LolCDE complex releases lipoproteins from the inner membrane of Escherichia coli in an ATP-dependent manner, leading to the formation of a complex between a lipoprotein and a periplasmic chaperone, LolA. LolA is proposed to undergo a conformational change upon the lipoprotein binding. The lipoprotein is then transferred from the LolA-lipoprotein complex to the outer membrane via LolB. Unlike most ATP binding cassette transporters med...

  6. Overexpression of the ATP-binding cassette half-transporter, ABCG2 (Mxr/BCrp/ABCP1), in flavopiridol-resistant human breast cancer cells

    DEFF Research Database (Denmark)

    Robey, R W; Medina-Pérez, W Y; Nishiyama, K

    2001-01-01

    microM. To determine putative mechanisms of resistance to flavopiridol, we exposed the human breast cancer cell line MCF-7 to incrementally increasing concentrations of flavopiridol. The resulting resistant subline, MCF-7 FLV1000, is maintained in 1,000 nM flavopiridol and was found to be 24-fold......We sought to characterize the interactions of flavopiridol with members of the ATP-binding cassette (ABC) transporter family. Cells overexpressing multidrug resistance-1 (MDR-1) and multidrug resistance-associated protein (MRP) did not exhibit appreciable flavopiridol resistance, whereas cell lines...... resistant to flavopiridol, as well as highly cross-resistant to mitoxantrone (675-fold), topotecan (423-fold), and SN-38 (950-fold), the active metabolite of irinotecan. Because this cross-resistance pattern is consistent with that reported for ABCG2-overexpressing cells, cytotoxicity studies were repeated...

  7. ABCC4与人类肿瘤%ATP-binding cassette transporter family class C4 and human cancer

    Institute of Scientific and Technical Information of China (English)

    石妮; 赵晓航

    2011-01-01

    ATP-binding cassette transporter family class C4 (ABCC4) is known as a member of the ATP-binding cassette transporter super-family, involved in the active transport of endogenous anions and xenobiotic, which is not normally produced or expected to be present in human, such as antibiotics. Recently it has been found that the copy number variations of Abcc4 gene and overexpression of ABCC4 protein in many kinds of human cancers, which might involved in tumorigenesis, progress and chemotherapeutic response. This review will focus on the ectopic expression of Abcc4 in human cancer and the potential role of ABCC4 in tumorigenesis and progress.%ABCC4(ATP-binding cassette transporter family class C4,ABCC4)是ABC蛋白家族成员,主要参与转运机体物质代谢中产生的有机阴离子和一些异型生物质等生物学功能.近年研究发现某些人类肿瘤存在Abcc4基因的拷贝数变异,主要表现为Abcc4基因拷贝数增加和ABCC4蛋白过表达,这些改变与肿瘤发生发展、耐药,以及治疗疗效具有相关性.该文综述了Abcc4基因的拷贝数变异和异常表达与肿瘤生物学特性的关系,探讨ABCC4在肿瘤发生发展中的作用机制.

  8. Involvement of CjMDR1, a plant multidrug-resistance-type ATP-binding cassette protein, in alkaloid transport in Coptis japonica

    Science.gov (United States)

    Shitan, Nobukazu; Bazin, Ingrid; Dan, Kazuyuki; Obata, Kazuaki; Kigawa, Koji; Ueda, Kazumitsu; Sato, Fumihiko; Forestier, Cyrille; Yazaki, Kazufumi

    2003-01-01

    Alkaloids comprise one of the largest groups of plant secondary metabolites. Berberine, a benzylisoquinoline alkaloid, is preferentially accumulated in the rhizome of Coptis japonica, a ranunculaceous plant, whereas gene expression for berberine biosynthetic enzymes has been observed specifically in root tissues, which suggests that berberine synthesized in the root is transported to the rhizome, where there is high accumulation. We recently isolated a cDNA encoding a multidrug-resistance protein (MDR)-type ATP-binding cassette (ABC) transporter (Cjmdr1) from berberine-producing cultured C. japonica cells, which is highly expressed in the rhizome. Functional analysis of Cjmdr1 by using a Xenopus oocyte expression system showed that CjMDR1 transported berberine in an inward direction, resulting in a higher accumulation of berberine in Cjmdr1-injected oocytes than in the control. Typical inhibitors of ABC proteins, such as vanadate, nifedipine, and glibenclamide, as well as ATP depletion, clearly inhibited this CjMDR1-dependent berberine uptake, suggesting that CjMDR1 functioned as an ABC transporter. Conventional membrane separation methods showed that CjMDR1 was localized in the plasma membrane of C. japonica cells. In situ hybridization indicated that Cjmdr1 mRNA was expressed preferentially in xylem tissues of the rhizome. These findings strongly suggest that CjMDR1 is involved in the translocation of berberine from the root to the rhizome. PMID:12524452

  9. ATP-binding cassette-like transporters are involved in the transport of lignin precursors across plasma and vacuolar membranes

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Y.C.; Liu, C.

    2010-12-28

    Lignin is a complex biopolymer derived primarily from the condensation of three monomeric precursors, the monolignols. The synthesis of monolignols occurs in the cytoplasm. To reach the cell wall where they are oxidized and polymerized, they must be transported across the cell membrane. However, the molecular mechanisms underlying the transport process are unclear. There are conflicting views about whether the transport of these precursors occurs by passive diffusion or is an energized active process; further, we know little about what chemical forms are required. Using isolated plasma and vacuolar membrane vesicles prepared from Arabidopsis, together with applying different transporter inhibitors in the assays, we examined the uptake of monolignols and their derivatives by these native membrane vesicles. We demonstrate that the transport of lignin precursors across plasmalemma and their sequestration into vacuoles are ATP-dependent primary-transport processes, involving ATP-binding cassette-like transporters. Moreover, we show that both plasma and vacuolar membrane vesicles selectively transport different forms of lignin precursors. In the presence of ATP, the inverted plasma membrane vesicles preferentially take up monolignol aglycones, whereas the vacuolar vesicles are more specific for glucoconjugates, suggesting that the different ATP-binding cassette-like transporters recognize different chemical forms in conveying them to distinct sites, and that glucosylation of monolignols is necessary for their vacuolar storage but not required for direct transport into the cell wall in Arabidopsis.

  10. Distinct alterations in ATP-binding cassette transporter expression in liver, kidney, small intestine, and brain in adjuvant-induced arthritic rats.

    Science.gov (United States)

    Kawase, Atsushi; Norikane, Sari; Okada, Ayaka; Adachi, Mamiko; Kato, Yukio; Iwaki, Masahiro

    2014-08-01

    Pathophysiological changes of infection or inflammation are associated with alterations in the production of numerous absorption, distribution, metabolism and excretion-related proteins. However, little information is available on the effects of inflammation on the expression levels and activities of ATP-binding cassette (ABC) transporters. We examined the effect of acute (on day 7) and chronic (on day 21) inflammation on the expression of ABC transporters in some major tissues in rat. Adjuvant-induced arthritis (AA) in rats was used as an animal model for inflammation. The mRNA levels of mdr1a and mdr1b encoding P-glycoprotein (P-gp) decreased significantly in livers of AA rats on day 21. Hepatic protein levels of P-gp, Mrp2, and Bcrp decreased significantly in membranes but not homogenates of AA rats after 7 days and after 21 days of treatment with adjuvant. Contrary to liver, protein levels of P-gp and Mrp2, but not Bcrp in kidney, increased significantly in membranes. The biliary excretion of rhodamine 123 was decreased in rats with chronic inflammation owing to decreases in efflux activities of P-gp. Our results showed that the expression of transporters in response to inflammation was organ dependent. In particular, hepatic and renal P-gp and Mrp2 exhibited opposite changes in membrane protein levels.

  11. Conformational changes of the bacterial type I ATP-binding cassette importer HisQMP2 at distinct steps of the catalytic cycle.

    Science.gov (United States)

    Heuveling, Johanna; Frochaux, Violette; Ziomkowska, Joanna; Wawrzinek, Robert; Wessig, Pablo; Herrmann, Andreas; Schneider, Erwin

    2014-01-01

    Prokaryotic solute binding protein-dependent ATP-binding cassette import systems are divided into type I and type II and mechanistic differences in the transport process going along with this classification are under intensive investigation. Little is known about the conformational dynamics during the catalytic cycle especially concerning the transmembrane domains. The type I transporter for positively charged amino acids from Salmonella enterica serovar Typhimurium (LAO-HisQMP2) was studied by limited proteolysis in detergent solution in the absence and presence of co-factors including ATP, ADP, LAO/arginine, and Mg(2+) ions. Stable peptide fragments could be obtained and differentially susceptible cleavage sites were determined by mass spectrometry as Lys-258 in the nucleotide-binding subunit, HisP, and Arg-217/Arg-218 in the transmembrane subunit, HisQ. In contrast, transmembrane subunit HisM was gradually degraded but no stable fragment could be detected. HisP and HisQ were equally resistant under pre- and post-hydrolysis conditions in the presence of arginine-loaded solute-binding protein LAO and ATP/ADP. Some protection was also observed with LAO/arginine alone, thus reflecting binding to the transporter in the apo-state and transmembrane signaling. Comparable digestion patterns were obtained with the transporter reconstituted into proteoliposomes and nanodiscs. Fluorescence lifetime spectroscopy confirmed the change of HisQ(R218) to a more apolar microenvironment upon ATP binding and hydrolysis. Limited proteolysis was subsequently used as a tool to study the consequences of mutations on the transport cycle. Together, our data suggest similar conformational changes during the transport cycle as described for the maltose ABC transporter of Escherichia coli, despite distinct structural differences between both systems.

  12. 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.

  13. Drug resistance is conferred on the model yeast Saccharomyces cerevisiae by expression of full-length melanoma-associated human ATP-binding cassette transporter ABCB5.

    Science.gov (United States)

    Keniya, Mikhail V; Holmes, Ann R; Niimi, Masakazu; Lamping, Erwin; Gillet, Jean-Pierre; Gottesman, Michael M; Cannon, Richard D

    2014-10-01

    ABCB5, an ATP-binding cassette (ABC) transporter, is highly expressed in melanoma cells, and may contribute to the extreme resistance of melanomas to chemotherapy by efflux of anti-cancer drugs. Our goal was to determine whether we could functionally express human ABCB5 in the model yeast Saccharomyces cerevisiae, in order to demonstrate an efflux function for ABCB5 in the absence of background pump activity from other human transporters. Heterologous expression would also facilitate drug discovery for this important target. DNAs encoding ABCB5 sequences were cloned into the chromosomal PDR5 locus of a S. cerevisiae strain in which seven endogenous ABC transporters have been deleted. Protein expression in the yeast cells was monitored by immunodetection using both a specific anti-ABCB5 antibody and a cross-reactive anti-ABCB1 antibody. ABCB5 function in recombinant yeast cells was measured by determining whether the cells possessed increased resistance to known pump substrates, compared to the host yeast strain, in assays of yeast growth. Three ABCB5 constructs were made in yeast. One was derived from the ABCB5-β mRNA, which is highly expressed in human tissues but is a truncation of a canonical full-size ABC transporter. Two constructs contained full-length ABCB5 sequences: either a native sequence from cDNA or a synthetic sequence codon-harmonized for S. cerevisiae. Expression of all three constructs in yeast was confirmed by immunodetection. Expression of the codon-harmonized full-length ABCB5 DNA conferred increased resistance, relative to the host yeast strain, to the putative substrates rhodamine 123, daunorubicin, tetramethylrhodamine, FK506, or clorgyline. We conclude that full-length ABCB5 can be functionally expressed in S. cerevisiae and confers drug resistance.

  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

    Science.gov (United States)

    Ceruso, Marina; Fratamico, Pina; Chirollo, Claudia; Taglialatela, Rosanna; Cortesi, Maria Luisa

    2014-01-01

    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 ΔLMOf2365_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. PMID:27800311

  15. Substrate Specificity and Ionic Regulation of GlnPQ from Lactococcus lactis. An ATP-Binding Cassette Transporter with Four Extracytoplasmic Substrate-Binding Domains

    NARCIS (Netherlands)

    Schuurman-Wolters, Gea K.; Poolman, Bert

    2005-01-01

    We report on the functional characterization of GlnPQ, an ATP-binding cassette transporter with four extracytoplasmic substrate-binding domains. The first predicted transmembrane helix of GlnP was cleaved off in the mature protein and most likely serves as the signal sequence for the extracytoplasmi

  16. Role of NH{sub 2}-terminal hydrophobic motif in the subcellular localization of ATP-binding cassette protein subfamily D: Common features in eukaryotic organisms

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Asaka; Asahina, Kota; Okamoto, Takumi; Kawaguchi, Kosuke [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Kostsin, Dzmitry G. [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Institute of Biophysics and Cell Engineering, National Academy of Sciences of Belarus, Academicheskaya Str. 27, Minsk 220072 (Belarus); Kashiwayama, Yoshinori [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Takanashi, Kojiro; Yazaki, Kazufumi [Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoko University, Uji, Kyoto 611-0011 (Japan); Imanaka, Tsuneo, E-mail: imanaka@pha.u-toyama.ac.jp [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Morita, Masashi [Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan)

    2014-10-24

    Highlights: • ABCD proteins classifies based on with or without NH{sub 2}-terminal hydrophobic segment. • The ABCD proteins with the segment are targeted peroxisomes. • The ABCD proteins without the segment are targeted to the endoplasmic reticulum. • The role of the segment in organelle targeting is conserved in eukaryotic organisms. - Abstract: In mammals, four ATP-binding cassette (ABC) proteins belonging to subfamily D have been identified. ABCD1–3 possesses the NH{sub 2}-terminal hydrophobic region and are targeted to peroxisomes, while ABCD4 lacking the region is targeted to the endoplasmic reticulum (ER). Based on hydropathy plot analysis, we found that several eukaryotes have ABCD protein homologs lacking the NH{sub 2}-terminal hydrophobic segment (H0 motif). To investigate whether the role of the NH{sub 2}-terminal H0 motif in subcellular localization is conserved across species, we expressed ABCD proteins from several species (metazoan, plant and fungi) in fusion with GFP in CHO cells and examined their subcellular localization. ABCD proteins possessing the NH{sub 2}-terminal H0 motif were localized to peroxisomes, while ABCD proteins lacking this region lost this capacity. In addition, the deletion of the NH{sub 2}-terminal H0 motif of ABCD protein resulted in their localization to the ER. These results suggest that the role of the NH{sub 2}-terminal H0 motif in organelle targeting is widely conserved in living organisms.

  17. The ABCC6 transporter: what lessons can be learnt from other ATP-binding cassette transporters?

    Directory of Open Access Journals (Sweden)

    Olivier M. Vanakker

    2013-10-01

    Full Text Available ABC transporters represent a large family of ATP-driven transmembrane transporters involved in uni- or bidirectional transfer of a variety of substrates. Divided in 7 families, they represent 48 transporter proteins, several of which are associated with human disease. Among the latter is ABCC6, a unidirectional exporter protein primarily expressed in liver and kidney. ABCC6 deficiency causes pseudoxanthoma elasticum (PXE, characterised by calcification and fragmentation of elastic fibres, resulting in oculocutaneous and cardiovascular symptoms. Unique among connective tissue disorders, the relation between the ABCC6 transporter and ectopic mineralization in PXE remains enigmatic, not in the least because of lack of knowledge on the substrate(s of ABCC6 and its unusual expression pattern. Because many features, including structure and transport mechanism, are shared by ABC transporters, it is worthwhile to evaluate if and to what extent the knowledge on the (pathophysiology of other transporters may provide useful clues towards understanding the (pathophysiological role of ABCC6. In this paper, we summarize relevant knowledge and methods for analysis on ABC transporters which may be useful for the further study of ABCC6.

  18. Suppression of c-Myc is involved in multi-walled carbon nanotubes' down-regulation of ATP-binding cassette transporters in human colon adenocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaojing [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China); Xu, Yonghong [Institute of Ophthalmological Research, Department of Ophthalmology, Renmin Hospital of Wuhan University, 430060 Wuhan (China); Meng, Xiangning [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Watari, Fumio [Department of Biomedical, Dental Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Sapporo 060-8586 (Japan); Liu, Hudan, E-mail: hudanliu@hust.edu.cn [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China); Chen, Xiao, E-mail: mornsmile@yahoo.com [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China)

    2015-01-01

    Over-expression of ATP-binding cassette (ABC) transporters, a large family of integral membrane proteins that decrease cellular drug uptake and accumulation by active extrusion, is one of the major causes of cancer multi-drug resistance (MDR) that frequently leads to failure of chemotherapy. Carbon nanotubes (CNTs)-based drug delivery devices hold great promise in enhancing the efficacy of cancer chemotherapy. However, CNTs' effects on the ABC transporters remain under-investigated. In this study, we found that multiwalled carbon nanotubes (MWCNTs) reduced transport activity and expression of ABC transporters including ABCB1/Pgp and ABCC4/MRP4 in human colon adenocarcinoma Caco-2 cells. Proto-oncogene c-Myc, which directly regulates ABC gene expression, was concurrently decreased in MWCNT-treated cells and forced over-expression of c-Myc reversed MWCNTs' inhibitory effects on ABCB1 and ABCC4 expression. MWCNT-cell membrane interaction and cell membrane oxidative damage were observed. However, antioxidants such as vitamin C, β-mecaptoethanol and dimethylthiourea failed to antagonize MWCNTs' down-regulation of ABC transporters. These data suggest that MWCNTs may act on c-Myc, but not through oxidative stress, to down-regulate ABC transporter expression. Our findings thus shed light on CNTs' novel cellular effects that may be utilized to develop CNTs-based drug delivery devices to overcome ABC transporter-mediated cancer chemoresistance.

  19. Galectin-3 silencing inhibits epirubicin-induced ATP binding cassette transporters and activates the mitochondrial apoptosis pathway via β-catenin/GSK-3β modulation in colorectal carcinoma.

    Directory of Open Access Journals (Sweden)

    Yung-Kuo Lee

    Full Text Available Multidrug resistance (MDR, an unfavorable factor compromising the treatment efficacy of anticancer drugs, involves the upregulation of ATP binding cassette (ABC transporters and induction of galectin-3 signaling. Galectin-3 plays an anti-apoptotic role in many cancer cells and regulates various pathways to activate MDR. Thus, the inhibition of galectin-3 has the potential to enhance the efficacy of the anticancer drug epirubicin. In this study, we examined the effects and mechanisms of silencing galectin-3 via RNA interference (RNAi on the β-catenin/GSK-3β pathway in human colon adenocarcinoma Caco-2 cells. Galectin-3 knockdown increased the intracellular accumulation of epirubicin in Caco-2 cells; suppressed the mRNA expression of galectin-3, β-catenin, cyclin D1, c-myc, P-glycoprotein (P-gp, MDR-associated protein (MRP 1, and MRP2; and downregulated the protein expression of P-gp, cyclin D1, galectin-3, β-catenin, c-Myc, and Bcl-2. Moreover, galectin-3 RNAi treatment significantly increased the mRNA level of GSK-3β, Bax, caspase-3, and caspase-9; remarkably increased the Bax-to-Bcl-2 ratio; and upregulated the GSK-3β and Bax protein expressions. Apoptosis was induced by galectin-3 RNAi and/or epirubicin as demonstrated by chromatin condensation, a higher sub-G1 phase proportion, and increased caspase-3 and caspase-9 activity, indicating an intrinsic/mitochondrial apoptosis pathway. Epirubicin-mediated resistance was effectively inhibited via galectin-3 RNAi treatment. However, these phenomena could be rescued after galectin-3 overexpression. We show for the first time that the silencing of galectin-3 sensitizes MDR cells to epirubicin by inhibiting ABC transporters and activating the mitochondrial pathway of apoptosis through modulation of the β-catenin/GSK-3β pathway in human colon cancer cells.

  20. Modulating the function of ATP-binding cassette subfamily G member 2 (ABCG2) with inhibitor cabozantinib.

    Science.gov (United States)

    Zhang, Guan-Nan; Zhang, Yun-Kai; Wang, Yi-Jun; Barbuti, Anna Maria; Zhu, Xi-Jun; Yu, Xin-Yue; Wen, Ai-Wen; Wurpel, John N D; Chen, Zhe-Sheng

    2017-01-25

    Cabozantinib (XL184) is a small molecule tyrosine kinase receptor inhibitor, which targets c-Met and VEGFR2. Cabozantinib has been approved by the Food and Drug Administration to treat advanced medullary thyroid cancer and renal cell carcinoma. In the present study, we evaluated the ability of cabozantinib to modulate the function of the ATP-binding cassette subfamily G member 2 (ABCG2) by sensitizing cells that are resistant to ABCG2 substrate antineoplastic drugs. We used a drug-selected resistant cell line H460/MX20 and three ABCG2 stable transfected cell lines ABCG2-482-R2, ABCG2-482-G2, and ABCG2-482-T7, which overexpress ABCG2. Cabozantinib, at non-toxic concentrations (3 or 5μM), sensitized the ABCG2-overexpressing cells to mitoxantrone, SN-38, and topotecan. Our results indicate that cabozantinib reverses ABCG2-mediated multidrug resistance by antagonizing the drug efflux function of the ABCG2 transporter instead of downregulating its expression. The molecular docking analysis indicates that cabozantinib binds to the drug-binding site of the ABCG2 transporter. Overall, our findings demonstrate that cabozantinib inhibits the ABCG2 transporter function and consequently enhances the effect of the antineoplastic agents that are substrates of ABCG2. Cabozantinib may be a useful agent in anticancer treatment regimens for patients who are resistant to ABCG2 substrate drugs.

  1. ATP-binding cassette transporter enhances tolerance to DDT in Tetrahymena.

    Science.gov (United States)

    Ning, YingZhi; Dang, Huai; Liu, GuangLong; Xiong, Jie; Yuan, DongXia; Feng, LiFang; Miao, Wei

    2015-03-01

    The reuse of dichlorodiphenyltrichloroethane (DDT) as an indoor residual spray was permitted by the World Health Organization in 2007, and approximately 14 countries still use DDT to control disease vectors. The extensive exposure of insects to DDT has resulted in the emergence of DDT resistance, especially in mosquitoes, and the mechanism for this resistance in mosquitoes has been widely reported. Spraying can also introduce DDT directly into surface water, and DDT can subsequently accumulate in microorganisms, but the mechanism for the resistance to DDT degradation in microorganisms is unclear. Using whole-genome microarray analysis, we detected an abcb15 gene that was up-regulated in a specific manner by DDT treatment in T. thermophile. The deduced ABCB15 peptide sequence had two transmembrane domains (TMDs) and two nucleotide-binding domains (NBDs) to form the structure TMD-NBD-TMD-NBD, and each NBD contained three conserved motifs: Walker-A, C-loop, and Walker-B, which indicated the T. thermophila abcb15 was a typical ABC transporter gene. The expression of ABCB15 fused with a C-terminal green fluorescent protein was found to be on the periphery of the cell, suggesting that ABCB15 was a membrane pump protein. In addition, cells with abcb15 partially knocked down (abcb15-KD) grew slower than wild-type cells in the presence of 256 mg L(-1) DDT, indicating the tolerance of abcb15-KD strain to DDT exposure was decreased. Thus, we suggest that in Tetrahymena, the membrane pump protein encoded by ABCT gene abcb15 can enhance the tolerance to DDT and protect cells from this exogenous toxin by efficiently pumping it to the extracellular space.

  2. Retinoic acid receptor agonists regulate expression of ATP-binding cassette transporter G1 in macrophages.

    Science.gov (United States)

    Ayaori, Makoto; Yakushiji, Emi; Ogura, Masatsune; Nakaya, Kazuhiro; Hisada, Tetsuya; Uto-Kondo, Harumi; Takiguchi, Shunichi; Terao, Yoshio; Sasaki, Makoto; Komatsu, Tomohiro; Iizuka, Maki; Yogo, Makiko; Uehara, Yoshinari; Kagechika, Hiroyuki; Nakanishi, Tsuyoshi; Ikewaki, Katsunori

    2012-04-01

    ABC transporter G1 (ABCG1) plays a pivotal role in HDL-mediated cholesterol efflux and atherogenesis. We investigated whether, and how, retinoic acid receptors (RARs) regulate ABCG1 expression in macrophages. All-trans retinoic acid (ATRA), an RAR ligand, increased ABCG1 protein levels and apoA-I/HDL-mediated cholesterol efflux from the macrophages. Both ATRA and other RAR agonists, TTNPB and Am580, increased major transcripts driven by promoter B upstream of exon 5, though minor transcripts driven by promoter A upstream of exon 1 were only increased by ATRA. The stimulatory effects of ATRA on ABCG1 expression were completely abolished in the presence of RAR/RXR antagonists but were only partially canceled in the presence of an LXR antagonist. Adenovirus with overexpressed oxysterol sulfotransferase abolished the LXR pathway, as previously reported, and ATRA-responsiveness in ABCA1/ABCG1 expressions were respectively attenuated by 38 and 22% compared to the control virus. Promoter assays revealed that ABCG1 levels were regulated more by promoter B than promoter A, and ATRA activated promoter B in a liver X receptor-responsive element (LXRE)-dependent manner. Further, LXRE-B in intron 7, but not LXRE-A in intron 5, enhanced ATRA responsiveness under overexpression of all RAR isoforms-RARα/β/γ. In contrast, the activation of promoter B by TTNPB depended on LXRE-B and RARα, but not on RARβ/γ. Finally, chromatin immunoprecipitation and gel-shift assays revealed a specific and direct repeat 4-dependent binding of RARα to LXRE-B. In conclusion, RAR ligands increase ABCA1/G1 expression and apoA-I/HDL-mediated cholesterol efflux from macrophages, and modulate ABCG1 promoter activity via LXRE-dependent mechanisms.

  3. Multidrug efflux pumps: the structures of prokaryotic ATP-binding cassette transporter efflux pumps and implications for our understanding of eukaryotic P-glycoproteins and homologues.

    Science.gov (United States)

    Kerr, Ian D; Jones, Peter M; George, Anthony M

    2010-02-01

    One of the Holy Grails of ATP-binding cassette transporter research is a structural understanding of drug binding and transport in a eukaryotic multidrug resistance pump. These transporters are front-line mediators of drug resistance in cancers and represent an important therapeutic target in future chemotherapy. Although there has been intensive biochemical research into the human multidrug pumps, their 3D structure at atomic resolution remains unknown. The recent determination of the structure of a mouse P-glycoprotein at subatomic resolution is complemented by structures for a number of prokaryotic homologues. These structures have provided advances into our knowledge of the ATP-binding cassette exporter structure and mechanism, and have provided the template data for a number of homology modelling studies designed to reconcile biochemical data on these clinically important proteins.

  4. Plant Vacuolar ATP-binding Cassette Transporters That Translocate Folates and Antifolates in Vitro and Contribute to Antifolate Tolerance in Vivo*

    OpenAIRE

    Raichaudhuri, Ayan; Peng, Mingsheng; Naponelli, Valeria; Chen, Sixue; Sánchez-Fernández, Rocío; Gu, Honglan; Gregory, Jesse F.; Hanson, Andrew D; Rea, Philip A.

    2009-01-01

    The vacuoles of pea (Pisum sativum) leaves and red beet (Beta vulgaris) storage root are major sites for the intracellular compartmentation of folates. In the light of these findings and preliminary experiments indicating that some plant multidrug resistance-associated protein (MRP) subfamily ATP-binding cassette transporters are able to transport compounds of this type, the Arabidopsis thaliana vacuolar MRP, AtMRP1 (AtABCC1), and its functional equivalent(s) in vacuol...

  5. Disruption of lolCDE, Encoding an ATP-Binding Cassette Transporter, Is Lethal for Escherichia coli and Prevents Release of Lipoproteins from the Inner Membrane

    OpenAIRE

    Narita, Shin-ichiro; Tanaka, Kimie; Matsuyama, Shin-ichi; Tokuda, Hajime

    2002-01-01

    ATP-binding cassette transporter LolCDE was previously identified, by using reconstituted proteoliposomes, as an apparatus catalyzing the release of outer membrane-specific lipoproteins from the inner membrane of Escherichia coli. Mutations resulting in defective LolD were previously shown to be lethal for E. coli. The amino acid sequences of LolC and LolE are similar to each other, but the necessity of both proteins for lipoprotein release has not been proved. Moreover, previous reconstituti...

  6. Biotin uptake in prokaryotes by solute transporters with an optional ATP-binding cassette-containing module.

    Science.gov (United States)

    Hebbeln, Peter; Rodionov, Dmitry A; Alfandega, Anja; Eitinger, Thomas

    2007-02-20

    BioMNY proteins are considered to constitute tripartite biotin transporters in prokaryotes. Recent comparative genomic and experimental analyses pointed to the similarity of BioMN to homologous modules of prokaryotic transporters mediating uptake of metals, amino acids, and vitamins. These systems resemble ATP-binding cassette-containing transporters and include typical ATPases (e.g., BioM). Absence of extracytoplasmic solute-binding proteins among the members of this group, however, is a distinctive feature. Genome context analyses uncovered that only one-third of the widespread bioY genes are linked to bioMN. Many bioY genes are located at loci encoding biotin biosynthesis, and others are unlinked to biotin metabolic or transport genes. Heterologous expression of the bioMNY operon and of the single bioY of the alpha-proteobacterium Rhodobacter capsulatus conferred biotin-transport activity on recombinant Escherichia coli cells. Kinetic analyses identified BioY as a high-capacity transporter that was converted into a high-affinity system in the presence of BioMN. BioMNY-mediated biotin uptake was severely impaired by replacement of the Walker A lysine residue in BioM, demonstrating dependency of high-affinity transport on a functional ATPase. Biochemical assays revealed that BioM, BioN, and BioY proteins form stable complexes in membranes of the heterologous host. Expression of truncated bio transport operons, each with one gene deleted, resulted in stable BioMN complexes but revealed only low amounts of BioMY and BioNY aggregates in the absence of the respective third partner. The results substantiate our earlier suggestion of a mechanistically novel group of membrane transporters.

  7. HIV-1 Protein Nef Inhibits Activity of ATP-binding Cassette Transporter A1 by Targeting Endoplasmic Reticulum Chaperone Calnexin*

    Science.gov (United States)

    Jennelle, Lucas; Hunegnaw, Ruth; Dubrovsky, Larisa; Pushkarsky, Tatiana; Fitzgerald, Michael L.; Sviridov, Dmitri; Popratiloff, Anastas; Brichacek, Beda; Bukrinsky, Michael

    2014-01-01

    HIV-infected patients are at increased risk of developing atherosclerosis, in part due to an altered high density lipoprotein profile exacerbated by down-modulation and impairment of ATP-binding cassette transporter A1 (ABCA1) activity by the HIV-1 protein Nef. However, the mechanisms of this Nef effect remain unknown. Here, we show that Nef interacts with an endoplasmic reticulum chaperone calnexin, which regulates folding and maturation of glycosylated proteins. Nef disrupted interaction between calnexin and ABCA1 but increased affinity and enhanced interaction of calnexin with HIV-1 gp160. The Nef mutant that did not bind to calnexin did not affect the calnexin-ABCA1 interaction. Interaction with calnexin was essential for functionality of ABCA1, as knockdown of calnexin blocked the ABCA1 exit from the endoplasmic reticulum, reduced ABCA1 abundance, and inhibited cholesterol efflux; the same effects were observed after Nef overexpression. However, the effects of calnexin knockdown and Nef on cholesterol efflux were not additive; in fact, the combined effect of these two factors together did not differ significantly from the effect of calnexin knockdown alone. Interestingly, gp160 and ABCA1 interacted with calnexin differently; although gp160 binding to calnexin was dependent on glycosylation, glycosylation was of little importance for the interaction between ABCA1 and calnexin. Thus, Nef regulates the activity of calnexin to stimulate its interaction with gp160 at the expense of ABCA1. This study identifies a mechanism for Nef-dependent inactivation of ABCA1 and dysregulation of cholesterol metabolism. PMID:25170080

  8. Up-regulation of the ATP-binding cassette transporter A1 inhibits hepatitis C virus infection.

    Directory of Open Access Journals (Sweden)

    Simone Bocchetta

    Full Text Available Hepatitis C virus (HCV establishes infection using host lipid metabolism pathways that are thus considered potential targets for indirect anti-HCV strategies. HCV enters the cell via clathrin-dependent endocytosis, interacting with several receptors, and virus-cell fusion, which depends on acidic pH and the integrity of cholesterol-rich domains of the hepatocyte membrane. The ATP-binding Cassette Transporter A1 (ABCA1 mediates cholesterol efflux from hepatocytes to extracellular Apolipoprotein A1 and moves cholesterol within cell membranes. Furthermore, it generates high-density lipoprotein (HDL particles. HDL protects against arteriosclerosis and cardiovascular disease. We show that the up-regulation of ABCA1 gene expression and its cholesterol efflux function in Huh7.5 hepatoma cells, using the liver X receptor (LXR agonist GW3965, impairs HCV infection and decreases levels of virus produced. ABCA1-stimulation inhibited HCV cell entry, acting on virus-host cell fusion, but had no impact on virus attachment, replication, or assembly/secretion. It did not affect infectivity or properties of virus particles produced. Silencing of the ABCA1 gene and reduction of the specific cholesterol efflux function counteracted the inhibitory effect of the GW3965 on HCV infection, providing evidence for a key role of ABCA1 in this process. Impaired virus-cell entry correlated with the reorganisation of cholesterol-rich membrane microdomains (lipid rafts. The inhibitory effect could be reversed by an exogenous cholesterol supply, indicating that restriction of HCV infection was induced by changes of cholesterol content/distribution in membrane regions essential for virus-cell fusion. Stimulation of ABCA1 expression by GW3965 inhibited HCV infection of both human primary hepatocytes and isolated human liver slices. This study reveals that pharmacological stimulation of the ABCA1-dependent cholesterol efflux pathway disrupts membrane cholesterol homeostasis

  9. Retinoic acid isomers up-regulate ATP binding cassette A1 and G1 and cholesterol efflux in rat astrocytes: implications for their therapeutic and teratogenic effects.

    Science.gov (United States)

    Chen, Jing; Costa, Lucio G; Guizzetti, Marina

    2011-09-01

    Recent studies suggest that retinoids may be effective in the treatment of Alzheimer's disease, although exposure to an excess of retinoids during gestation causes teratogenesis. Cholesterol is essential for brain development, but high levels of cholesterol have been associated with Alzheimer's disease. We hypothesized that retinoic acid may affect cholesterol homeostasis in rat astrocytes, which regulate cholesterol distribution in the brain, through the up-regulation of cholesterol transporters ATP binding cassette (Abc)a1 and Abcg1. Tretinoin, 13-cis retinoic acid (13-cis-RA), 9-cis-RA, and the selective retinoid X receptor (RXR) agonist methoprene significantly increased cholesterol efflux induced by cholesterol acceptors and protein levels of Abca1 by 2.3- (± 0.25), 3.6- (± 0.42), 4.1- (± 0.5), and 1.75- (± 0.43) fold, respectively, and Abcg1 by 2.1- (± 0.26), 2.2- (± 0.33), 2.5- (± 0.23), and 2.2- (± 0.21) fold, respectively. 13-cis-RA and 9-cis-RA also significantly increased mRNA levels of Abca1 (maximal induction 7.3 ± 0.42 and 2.7 ± 0.17, respectively) and Abcg1 (maximal induction 2.0 ± 0.18 and 1.8 ± 0.09, respectively), and the levels of membrane-bound Abca1 (2.5 ± 0.3 and 2.5 ± 0.40-fold increase, respectively), whereas they significantly decreased intracellular cholesterol content without affecting cholesterol synthesis. The effect of 9-cis-RA on cholesterol homeostasis in astrocytes can be ascribed to the activation of RXR, whereas the effects of 13-cis-RA and tretinoin were independent of either RXRs or retinoic acid receptors. These findings suggest that retinoids affect cholesterol homeostasis in astrocytes and that this effect may be involved in both their therapeutic and teratogenic actions.

  10. Single amino acid mutation in an ATP-binding cassette transporter gene causes resistance to Bt toxin Cry1Ab in the silkworm, Bombyx mori.

    Science.gov (United States)

    Atsumi, Shogo; Miyamoto, Kazuhisa; Yamamoto, Kimiko; Narukawa, Junko; Kawai, Sawako; Sezutsu, Hideki; Kobayashi, Isao; Uchino, Keiro; Tamura, Toshiki; Mita, Kazuei; Kadono-Okuda, Keiko; Wada, Sanae; Kanda, Kohzo; Goldsmith, Marian R; Noda, Hiroaki

    2012-06-19

    Bt toxins derived from the arthropod bacterial pathogen Bacillus thuringiensis are widely used for insect control as insecticides or in transgenic crops. Bt resistance has been found in field populations of several lepidopteran pests and in laboratory strains selected with Bt toxin. Widespread planting of crops expressing Bt toxins has raised concerns about the potential increase of resistance mutations in targeted insects. By using Bombyx mori as a model, we identified a candidate gene for a recessive form of resistance to Cry1Ab toxin on chromosome 15 by positional cloning. BGIBMGA007792-93, which encodes an ATP-binding cassette transporter similar to human multidrug resistance protein 4 and orthologous to genes associated with recessive resistance to Cry1Ac in Heliothis virescens and two other lepidopteran species, was expressed in the midgut. Sequences of 10 susceptible and seven resistant silkworm strains revealed a common tyrosine insertion in an outer loop of the predicted transmembrane structure of resistant alleles. We confirmed the role of this ATP-binding cassette transporter gene in Bt resistance by converting a resistant silkworm strain into a susceptible one by using germline transformation. This study represents a direct demonstration of Bt resistance gene function in insects with the use of transgenesis.

  11. Change in ATP-binding cassette B1/19, glutamine synthetase and alcohol dehydrogenase gene expression during root elongation in Betula pendula Roth and Alnus glutinosa L. Gaertn in response to leachate and leonardite humic substances.

    Science.gov (United States)

    Tahiri, Abdelghani; Delporte, Fabienne; Muhovski, Yordan; Ongena, Marc; Thonart, Philippe; Druart, Philippe

    2016-01-01

    Humic substances (HS) are complex and heterogeneous compounds of humified organic matter resulting from the chemical and microbiological decomposition of organic residues. HS have a positive effect on plant growth and development by improving soil structure and fertility. They have long been recognized as plant growth-promoting substances, particularly with regard to influencing nutrient uptake, root growth and architecture. The biochemical and molecular mechanisms through which HS influence plant physiology are not well understood. This study evaluated the bioactivity of landfill leachate and leonardite HS on alder (Alnus glutinosa L. Gaertn) and birch (Betula pendula Roth) during root elongation in vitro. Changes in root development were studied in relation to auxin, carbon and nitrogen metabolisms, as well as to the stress adaptive response. The cDNA fragments of putative genes encoding two ATP-binding cassette (ABC) transporters (ABCB1 and ABCB19) belonging to the B subfamily of plant ABC auxin transporters were cloned and sequenced. Molecular data indicate that HS and their humic acid (HA) fractions induce root growth by influencing polar auxin transport (PAT), as illustrated by the modulation of the ABCB transporter transcript levels (ABCB1 and ABCB19). There were also changes in alcohol dehydrogenase (ADH) and glutamine synthetase (GS) gene transcript levels in response to HS exposure. These findings confirmed that humic matter affects plant growth and development through various metabolic pathways, including hormonal, carbon and nitrogen metabolisms and stress response or signalization.

  12. Afatinib reverses multidrug resistance in ovarian cancer via dually inhibiting ATP binding cassette subfamily B member 1.

    Science.gov (United States)

    Wang, Sheng-qi; Liu, Shi-ting; Zhao, Bo-xin; Yang, Fu-heng; Wang, Ya-tian; Liang, Qian-Ying; Sun, Ya-bin; Liu, Yuan; Song, Zhi-hua; Cai, Yun; Li, Guo-feng

    2015-09-22

    ABCB1-mediated multidrug resistance (MDR) remains a major obstacle to successful chemotherapy in ovarian cancer. Herein, afatinib at nontoxic concentrations significantly reversed ABCB1-mediated MDR in ovarian cancer cells in vitro (p afatinib caused tumor regressions and tumor necrosis in A2780T xenografts in vivo. More interestingly, unlike reversible TKIs, afatinib had a distinctive dual-mode action. Afatinib not only inhibited the efflux function of ABCB1, but also attenuated its expression transcriptionally via down-regulation of PI3K/AKT and MAPK/p38-dependent activation of NF-κB. Furthermore, apart from a substrate binding domain, afatinib could also bind to an ATP binding domain of ABCB1 through forming hydrogen bonds with Gly533, Gly534, Lys536 and Ala560 sites. Importantly, mutations in these four binding sites of ABCB1 and the tyrosine kinase domain of EGFR were not correlated with the reversal activity of afatinib on MDR. Given that afatinib is a clinically approved drug, our results suggest combining afatinib with chemotherapeutic drugs in ovarian cancer. This study can facilitate the rediscovery of superior MDR reversal agents from molecular targeted drugs to provide a more effective and safer way of resensitizing MDR.

  13. Cholesterol efflux via ATP-binding cassette transporter A1 (ABCA1) and cholesterol uptake via the LDL receptor influences cholesterol-induced impairment of beta cell function in mice

    NARCIS (Netherlands)

    Kruit, J. K.; Kremer, P. H. C.; Dai, L.; Tang, R.; Ruddle, P.; de Haan, W.; Brunham, L. R.; Verchere, C. B.; Hayden, M. R.

    2010-01-01

    Cellular cholesterol accumulation is an emerging mechanism for beta cell dysfunction in type 2 diabetes. Absence of the cholesterol transporter ATP-binding cassette transporter A1 (ABCA1) results in increased islet cholesterol and impaired insulin secretion, indicating that impaired cholesterol effl

  14. Pharmacophore modeling of nilotinib as an inhibitor of ATP-binding cassette drug transporters and BCR-ABL kinase using a three-dimensional quantitative structure-activity relationship approach.

    Science.gov (United States)

    Shukla, Suneet; Kouanda, Abdul; Silverton, Latoya; Talele, Tanaji T; Ambudkar, Suresh V

    2014-07-07

    Nilotinib (Tasigna) is a tyrosine kinase inhibitor approved by the FDA to treat chronic phase chronic myeloid leukemia patients. It is also a transport substrate of the ATP-binding cassette (ABC) drug efflux transporters ABCB1 (P-glycoprotein, P-gp) and ABCG2 (BCRP), which may have an effect on the pharmacokinetics and toxicity of this drug. The goal of this study was to identify pharmacophoric features of nilotinib in order to potentially develop specific inhibitors of BCR-ABL kinase with minimal interactions with ABC drug transporters. Three-dimensional pharmacophore modeling and quantitative structure-activity relationship (QSAR) studies were carried out on a series of nilotinib analogues to identify chemical features that contribute to inhibitory activity of nilotinib against BCR-ABL kinase activity, P-gp, and ABCG2. Twenty-five derivatives of nilotinib were synthesized and were then tested to measure their activity to inhibit BCR-ABL kinase and to inhibit the function of ABC drug transporters. A set of in vitro experiments including kinase activity and cell-based transport assays and photolabeling of P-gp and ABCG2 with a transport substrate, [(125)I]-iodoarylazido-prazosin (IAAP), were carried out in isolated membranes to evaluate the potency of the derivatives to inhibit the function of ABC drug transporters and BCR-ABL kinase. Sixteen, fourteen, and ten compounds were selected as QSAR data sets, respectively, to generate PHASE v3.1 pharmacophore models for BCR-ABL kinase, ABCG2, and P-gp inhibitors. The IC50 values of these derivatives against P-gp, ABCG2, or BCR-ABL kinase were used to generate pharmacophore features required for optimal interactions with these targets. A seven-point pharmacophore (AADDRRR) for BCR-ABL kinase inhibitory activity, a six-point pharmacophore (ADHRRR) for ABCG2 inhibitory activity, and a seven-point pharmacophore (AADDRRR) for P-gp inhibitory activity were generated. The derived models clearly demonstrate high predictive power

  15. Heterocyclic cyclohexanone monocarbonyl analogs of curcumin can inhibit the activity of ATP-binding cassette transporters in cancer multidrug resistance.

    Science.gov (United States)

    Revalde, Jezrael L; Li, Yan; Hawkins, Bill C; Rosengren, Rhonda J; Paxton, James W

    2015-02-01

    Curcumin (CUR) is a phytochemical that inhibits the xenobiotic ABC efflux transporters implicated in cancer multidrug resistance (MDR), such as P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins 1 and 5 (MRP1 and MRP5). The use of CUR in the clinic however, is complicated by its instability and poor pharmacokinetic profile. Monocarbonyl analogs of CUR (MACs) are compounds without CUR's unstable β-diketone moiety and were reported to have improved stability and in vivo disposition. Whether the MACs can be used as MDR reversal agents is less clear, as the absence of a β-diketone may negatively impact transporter inhibition. In this study, we investigated 23 heterocyclic cyclohexanone MACs for inhibitory effects against P-gp, BCRP, MRP1 and MRP5. Using flow cytometry and resistance reversal assays, we found that many of these compounds inhibited the transport activity of the ABC transporters investigated, often with much greater potency than CUR. Overall the analogs were most effective at inhibiting BCRP and we identified three compounds, A12 (2,6-bis((E)-2,5-dimethoxy-benzylidene)cyclohexanone), A13 (2,6-bis((E)-4-hydroxyl-3-methoxybenzylidene)-cyclohexanone) and B11 (3,5-bis((E)-2-fluoro-4,5-dimethoxybenzylidene)-1-methylpiperidin-4-one), as the most promising BCRP inhibitors. These compounds inhibited BCRP activity in a non-cell line, non-substrate-specific manner. Their inhibition occurred by direct transporter interaction rather than modulating protein or cell surface expression. From these results, we concluded that MACs, such as the heterocyclic cyclohexanone analogs in this study, also have potential as MDR reversal agents and may be superior alternatives to the unstable parent compound, CUR.

  16. Inherited surfactant deficiency due to uniparental disomy of rare mutations in the surfactant protein-B and ATP binding cassette, subfamily A, member 3 genes

    Science.gov (United States)

    Hamvas, Aaron; Nogee, Lawrence M.; Wegner, Daniel J.; DePass, Kelcey; Christodoulou, John; Bennetts, Bruce; McQuade, Leon R.; Gray, Peter H.; Deterding, Robin R.; Carroll, Travis R.; Kammesheidt, Anja; Kasch, Laura M.; Kulkarni, Shashikant; Cole, F. Sessions

    2009-01-01

    Objective To characterize inheritance of homozygous, rare, recessive loss-of-function mutations in the surfactant protein-B (SFTPB) or ATP binding cassette, subfamily A, member 3 (ABCA3) genes in newborns with lethal respiratory failure. Study design We resequenced parents whose infants were homozygous for mutations in SFTPB or ABCA3. For infants with only one heterozygous parent, we performed microsatellite analysis for chromosomes 2 (SFTPB) and 16 (ABCA3). Results We identified one infant homozygous for the c.1549C>GAA mutation (121ins2) in SFTPB for whom only the mother was heterozygous and 3 infants homozygous for mutations in ABCA3 (p.K914R, p.P147L, and c.806_7insGCT) for whom only the fathers were heterozygous. For the SP-B deficient infant, microsatellite markers confirmed maternal heterodisomy with segmental isodisomy. Microsatellite analysis confirmed paternal isodisomy for the three ABCA3 deficient infants. Two ABCA3 deficient infants underwent lung transplantation at 3 and 5 months of age, respectively, and two infants died. None exhibited any non-pulmonary phenotype. Conclusions Uniparental disomy should be suspected in infants with rare homozygous mutations in SFTPB or ABCA3. Confirmation of parental carrier status is important to provide recurrence risk and to monitor expression of other phenotypes that may emerge through reduction to homozygosity of recessive alleles. PMID:19647838

  17. Seminal Plasma Characteristics and Expression of ATP-binding Cassette Transporter A1 (ABCA1) in Canine Spermatozoa from Ejaculates with Good and Bad Freezability.

    Science.gov (United States)

    Schäfer-Somi, S; Palme, N

    2016-04-01

    The composition of seminal plasma and the localization of the ATP-binding cassette transporter A1 (ABCA1) in spermatozoa from good and bad freezers were compared to frozen-thawed spermatozoa from the same dog. Ejaculates were obtained from 31 stud dogs, and the sperm-rich fraction (SRF) was kept for analysis. One aliquot was used for the analysis of concentration, progressive motility (P; CASA), viability (V; CASA) and leucocyte count, and the analysis was performed by flow cytometry (FITC-PNA/PI), SCSA and HOST. In seminal plasma, concentration of albumin, cholesterol, calcium, inorganic phosphate, sodium, potassium, zinc and copper was measured. Semen smears were prepared and evaluated for the expression of ABCA1. The remainder of each ejaculate was frozen. After thawing, the quality assessment was repeated and further smears were prepared. According to post-thaw semen quality, dogs were assigned to good freezers (n = 20) or bad freezers (n = 11), the latter were defined as 40% morphologically abnormal sperm and/or Bad freezers were older than good freezers (5.3 vs 3.4 years, p bad freezers, the percentage of sperm with ABCA1 signal in the acrosome was lower (26.3% vs 35.7%, p good freezers (p bad freezer sperm, an increase in acrosome damages coincided with an increased loss of cholesterol transporters and cell death, and a lower cholesterol concentration in seminal plasma. Follow-up studies revealed whether a relation exists between these findings.

  18. Lipid absorption defects in intestine-specific microsomal triglyceride transfer protein and ATP-binding cassette transporter A1-deficient mice.

    Science.gov (United States)

    Iqbal, Jahangir; Parks, John S; Hussain, M Mahmood

    2013-10-18

    We have previously described apolipoprotein B (apoB)-dependent and -independent cholesterol absorption pathways and the role of microsomal triglyceride transfer protein (MTP) and ATP-binding cassette transporter A1 (ABCA1) in these pathways. To assess the contribution of these pathways to cholesterol absorption and to determine whether there are other pathways, we generated mice that lack MTP and ABCA1, individually and in combination, in the intestine. Intestinal deletions of Mttp and Abca1 decreased plasma cholesterol concentrations by 45 and 24%, respectively, whereas their combined deletion reduced it by 59%. Acute cholesterol absorption was reduced by 28% in the absence of ABCA1, and it was reduced by 92-95% when MTP was deleted in the intestine alone or together with ABCA1. MTP deficiency significantly reduced triglyceride absorption, although ABCA1 deficiency had no effect. ABCA1 deficiency did not affect cellular lipids, but Mttp deficiency significantly increased intestinal levels of triglycerides and free fatty acids. Accumulation of intestinal free fatty acids, but not triglycerides, in Mttp-deficient intestines was prevented when mice were also deficient in intestinal ABCA1. Combined deficiency of these genes increased intestinal fatty acid oxidation as a consequence of increased expression of peroxisome proliferator-activated receptor-γ (PPARγ) and carnitine palmitoyltransferase 1α (CPT1α). These studies show that intestinal MTP and ABCA1 are critical for lipid absorption and are the main determinants of plasma and intestinal lipid levels. Reducing their activities might lower plasma lipid concentrations.

  19. Lobular Distribution and Variability in Hepatic ATP Binding Cassette Protein B1 (ABCB1, P-gp): Ontogenetic Differences and Potential for Toxicity

    Science.gov (United States)

    Abanda, Ngu Njei; Riches, Zoe; Collier, Abby C.

    2017-01-01

    The ATP Binding Cassette B1 (ABCB1) transporter has critical roles in endo- and xenobiotic efficacy and toxicity. To understand population variability in hepatic transport we determined ABCB1 mRNA and protein levels in total liver lysates sampled from 8 pre-defined sites (n = 24, 18–69 years), and in S9 from randomly acquired samples (n = 87, 7 days–87 years). ABCB1 levels did not differ significantly throughout individual livers and showed 4.4-fold protein variation between subjects. Neither mRNA nor protein levels varied with sex, ethnicity, obesity or triglycerides in lysates or S9 (that showed the same relationships), but protein levels were lower in pediatric S9 (p < 0.0001), with 76% of adult ABCB1 present at birth and predicted to mature in 5 years. Pediatric total liver lysates were not available. In summary, opportunistic collection for studying human hepatic ABCB1 is acceptable. Additionally, ABCB1 may be lower in children, indicating differential potential for toxicity and response to therapy in this special population. PMID:28218636

  20. Enhancement of avermectin and ivermectin production by overexpression of the maltose ATP-binding cassette transporter in Streptomyces avermitilis.

    Science.gov (United States)

    Li, Meng; Chen, Zhi; Zhang, Xuan; Song, Yuan; Wen, Ying; Li, Jilun

    2010-12-01

    We investigated the function of maltose ABC transporter system encoded by malEFG-a and the effect of its overexpression on antibiotic production in Streptomyces avermitilis. A malEFG-a deletion mutant was unable to grow in a minimal medium with maltose as sole carbon source and produce avermectin. Maltose utilization and avermectin production were restored by introduction of a single copy of malEFG-a. RT-PCR analysis showed that the expression of malE-a was induced by maltose, and was strongly repressed by glucose. When multi-copy, integrative malEFG-a gene expression vectors were introduced into wild-type strain ATCC31267 and ivermectin-producer OI-31, antibiotic production increased by 2.6- to 3.3-fold and the time required for fermentation decreased by about 10%. The overexpression of malEFG-a improved the utilization rate of starch, and thereby enhanced avermectin production. Such an approach would be useful for the improvement of commercial antibiotic production using starch as the main carbon source in the fermentation process.

  1. The multi-xenobiotic resistance (MXR) efflux activity in hemocytes of Mytilus edulis is mediated by an ATP binding cassette transporter of class C (ABCC) principally inducible in eosinophilic granulocytes.

    Science.gov (United States)

    Rioult, Damien; Pasquier, Jennifer; Boulangé-Lecomte, Céline; Poret, Agnès; Abbas, Imane; Marin, Matthieu; Minier, Christophe; Le Foll, Frank

    2014-08-01

    In marine and estuarine species, immunotoxic and/or immunomodulatory mechanisms are the crossroad of interactions between xenobiotics, microorganisms and physicochemical variations of the environment. In mussels, immunity relies exclusively on innate responses carried out by cells collectively called hemocytes and found in the open hemolymphatic circulatory system of these organisms. However, hemocytes do not form a homogenous population of immune cells since distinct subtypes of mussel blood cells can be distinguished by cytochemistry, flow cytometry or cell motility analysis. Previous studies have also shown that these cells are able to efflux xenobiotics by means of ATP binding cassette (ABC) transporter activities conferring a multixenobiotic resistance (MXR) phenotype. ABC transporters corresponding to vertebrate class B/P-glycoprotein (P-gp) and to class C/multidrug resistance related protein (MRP) are characterized in Mytilidae. Herein, we have investigated the relative contributions of ABCB- and ABCC-mediated efflux within the different hemocyte subpopulations of Mytilus edulis mussels, collected from areas differentially impacted by chemical contaminants in Normandy (France). RT-PCR analyses provide evidence for the presence of ABCB and ABCC transporters transcripts in hemocytes. Immunodetection of ABCB/P-gp with the monoclonal antibody UIC2 in living hemocytes revealed that expression was restricted to granular structures of spread cells. Efflux transporter activities, with calcein-AM as fluorescent probe, were measured by combining flow cytometry to accurate Coulter cell size measurements in order to get a cell-volume normalized fluorescence concentration. In these conditions, basal fluorescence levels were higher in hemocytes originating from Yport (control site) than in cells collected from the harbor of Le Havre, where mussels are more exposed to with persistent pollutants. By using specific ABCB/P-gp (verapamil, PSC833, zosuquidar) and ABCC/MRP (MK

  2. Lipid raft involved in drug resistance: relationship between multidrug resistance ATP-binding cassette transporters and lipid raft%脂筏参与耐药: 多药耐药相关ABC转运蛋白与脂筏的关系

    Institute of Scientific and Technical Information of China (English)

    王琳; 贾宇; 姜远英

    2011-01-01

    Lipid rafts have been implicated in many cellular functions, including protein and lipid transport and signal transduction. Recently ATP-binding cassette (ABC) transporters, which are associated with multidrug resistance, have been found in lipid rafts; therefore they might be related to drug resistance. Here we introduce the relationship between the localization and functions of three multi-drug related ABC transporters, including two relevant to multidrug resistance in tumor cells(Pgp/ABCB1 and MRP1/ABCC1) and one relevant to multidrug resistance in Candida albicans (Cdrlp). We also discuss the influence of sphingolipids and cholesterol, two major components of lipid rafts, on the localization and function of the above three ABC transporters.%脂筏(lipid raft)和细胞的许多功能,如信号转导、蛋白质和脂类的转运等都相关.近来有研究发现,与多药耐药密切相关的ABC转运蛋白(ATP-binding cassette transporter)定位于脂筏中,因此推测脂筏可能与耐药性有一定关系.本文综述了3种和耐药相关的ABC转运蛋白的定位与其功能之间的联系,分别是和肿瘤细胞多药耐药相关的ABC转运蛋白Pgp/ABCB1、MRP1/ABCC1以及与白假丝酵母菌(白念珠菌)多药耐药相关的ABC转运蛋白Cdr1p;并进一步讨论了脂筏的重要组成成分胆固醇和鞘脂对上述3种ABC转运蛋白的定位和功能的影响.

  3. Natural allelic variants of bovine ATP-binding cassette transporter ABCG2: increased activity of the Ser581 variant and development of tools for the discovery of new ABCG2 inhibitors.

    Science.gov (United States)

    Merino, Gracia; Real, Rebeca; Baro, Marta F; Gonzalez-Lobato, Lucia; Prieto, Julio G; Alvarez, Ana I; Marques, Margarita M

    2009-01-01

    ATP-binding cassette transporter ABCG2 [breast cancer resistance protein (BCRP)] is a member of the ABC transporter superfamily that actively extrudes xenotoxins from cells and is a major determinant of the bioavailability of many compounds. ABCG2 expression is strongly induced during lactation in the mammary gland and is related to the active secretion of drugs into the milk. The presence of drug residues and environmental pollutants in milk is an outstanding problem for human milk consumption and milk industrial processes, involving important risks to public health and the dairy industry. In cows, a single nucleotide polymorphism (SNP) in this protein has been described previously (Tyr581) and is associated with higher fat and protein percentages and lower milk yield. However, whether this amino acid substitution affects ABCG2-mediated drug transport in cows, including milk secretion, required further exploration. We cloned the two variants of bovine ABCG2 and evaluated the effect of this SNP on mitoxantrone accumulation assays performed in ovine primary fibroblasts transiently expressing either of the variants. It is interesting to note that statistically significant differences in activity between both variants were observed, and the Ser581 variant was related with an increased efflux activity. In addition, we demonstrated that genistein is a very good inhibitor of bovine ABCG2 and identified new inhibitors of the transporter, such as the macrocyclic lactones, ivermectin, and selamectin. Moreover, the inhibitory effect of these compounds on human and murine ABCG2 homologs was confirmed using transduced Marbin-Dabin canine kidney II cells. These findings may have important implications regarding the presence of drug residues in milk and drug interactions affecting the pharmacological behavior of ABCG2 substrates.

  4. Effect of Apolipoprotein A-I on ATP Binding Cassette Transporter A1 Degradation and Cholesterol Efflux in THP-1 Macrophage-derived Foam Cells

    Institute of Scientific and Technical Information of China (English)

    Chao-Ke TANG; Chang-Geng RUAN; Yong-Zong YANG; Guo-Hua TANG; Guang-Hui IY; Zuo WANG; Lu-Shan LIU; Shuang WAN; Zhong-Hua YUAN; Xiu-Sheng HE; Jun-Hao YANG

    2004-01-01

    Cholesterol-loaded macrophage foam cells are a central componentof atherosclerotic lesions ATP binding cassette transporter A1(ABCA1),the defective molecule in Tangier disease,mediates the efflux ofphospholipid and cholesterol from cells to apolipoprotein A-I(apoA-I),reversing foam cell formation.This study investigated the effect of apoA-I on ABCA1 degradation and cholesterol efflux in THP-1 macrophagederived foam cells.After exposure of the cultured THP-1 macrophage-derived foam cells to apoA-I for different time,cholesterol efflux,ABCA1 mRNA and protein levels were determined by FJ-2107P type liquid scintillator,RT-PCR and Western blot,respectively.The mean ABCA1 fluorescence intensity on THP-1macrophage-derived foam cells was detected by flow cytometry.Results showed that apoA-I markedly increased ABCAl-mediated cholesterol efflux from THP-1 macrophage-derived foam cells.This was accompanied by an increase in the content of ABCA1.ApoA-I did not alter ABCA 1 mRNA abundance.Significantly,thiol protease inhibitors increased the level ofABCA1 protein and slowed its decay in THP-1macrophage-derived foam cells,whereas none of the proteosome-specific inhibitor lactacystin,other protease inhibitors,or the lysosomal inhibitor NH4Cl showed such effects.The apoA-I-mediated cellular cholesterol efflux was enhanced by thiol protease inhibitors.Our results suggested that thiol protease inhibitors mightprovide an alternative way to upregulate ABCA1 protein.This strategy is especially appealing since it may mimic the stabilizing effect of the natural ligands apoA-I.

  5. Polycyclic aromatic hydrocarbons (PAHs) mediate transcriptional activation of the ATP binding cassette transporter ABCB6 gene via the aryl hydrocarbon receptor (AhR).

    Science.gov (United States)

    Chavan, Hemantkumar; Krishnamurthy, Partha

    2012-09-14

    Liver is endowed with a mechanism to induce hepatic cytochromes P450 (CYP450s) in response to therapeutic drugs and environmental contaminants, leading to increased detoxification and elimination of the xenobiotics. Each CYP450 is composed of an apoprotein moiety and a heme prosthetic group, which is required for CYP450 activity. Thus, under conditions of CYP450 induction, there is a coordinate increase in heme biosynthesis to compensate for the increased expression of CYP450s. ABCB6, a mitochondrial ATP binding cassette transporter, which regulates coproporphyrinogen transport from the cytoplasm into the mitochondria to complete heme biosynthesis, represents a previously unrecognized rate-limiting step in heme biosynthesis. However, it is not known if exposure to drugs and environmental contaminants induces ABCB6 expression, to assure an adequate and apparently coordinated supply of heme for the generation of functional cytochrome holoprotein. In the present study, we demonstrate that polycyclic aromatic hydrocarbons (PAHs), the widely distributed environmental toxicants shown to induce porphyrin accumulation causing hepatic porphyria, up-regulate ABCB6 expression in both mice and humans. Using siRNA technology and Abcb6 knock-out mice, we demonstrate that PAH-mediated increase in hepatic porphyrins is compromised in the absence of ABCB6. Moreover, in vivo studies in aryl hydrocarbon receptor (AhR) knock-out mice demonstrate that PAH induction of ABCB6 is mediated by AhR. Promoter activation studies combined with electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrate direct interactions between the AhR binding sites in the ABCB6 promoter and the AhR receptor, implicating drug activation mechanisms for ABCB6 similar to those found in inducible cytochrome P450s. These studies are the first to describe direct transcriptional activation of both mouse and human ABCB6 by xenobiotics.

  6. Prognostic significance and molecular mechanism of ATP-binding cassette subfamily C member 4 in resistance to neoadjuvant radiotherapy of locally advanced rectal carcinoma.

    Directory of Open Access Journals (Sweden)

    Zhiqi Yu

    Full Text Available BACKGROUND: Mechanism of radioresistance in rectal carcinoma remains largely unknown. We aimed to evaluate the predictive role of ATP-binding cassette subfamily C member 4 (ABCC4 in locally advanced rectal carcinoma and explore possible molecular mechanisms by which ABCC4 confers the resistance to neoadjuvant radiotherapy. METHODS: The expression of ABCC4 and P53 mutant in biopsy tissue specimens from 121 locally advanced rectal carcinoma patients was examined using immunohistochemistry. The factors contributing to 3-year overall survival and disease-free survival were evaluated using the Kaplan-Meier method and Cox proportional hazard model. Lentivirus-mediated small hairpin RNA was applied to inhibit ABCC4 expression in colorectal carcinoma cell line RKO, and investigate the radiosensitivity in xenograft model. Intracellular cyclic adenosine monophosphate concentration and cell cycle distribution following irradiation were detected. RESULTS: High expression of ABCC4 and p53 mutant in pretreated tumors, poor pathological response, and high final tumor staging were significant factors independently predicted an unfavorable prognosis of locally advanced rectal carcinoma patients after neoadjuvant radiotherapy. Down-regulation of ABCC4 expression significantly enhanced irradiation-induced suppression of tumor growth in xenograft model. Furthermore, down-regulation of ABCC4 expression enhanced intracellular cyclic adenosine monophosphate production and noticeable deficiency of G1-S phase checkpoint in cell cycle following irradiation. CONCLUSIONS: Our study suggests that ABCC4 serves as a novel predictive biomarker that is responsible for the radioresistance and predicts a poor prognosis for locally advanced rectal carcinoma after neoadjuvant radiotherapy.

  7. Role of ATP binding and hydrolysis in the gating of the cystic fibrosis transmembrane conductance regulator

    Directory of Open Access Journals (Sweden)

    Taras Gout

    2012-01-01

    Full Text Available The CFTR gene is unique within the ATP-binding cassette (ABC protein family, predominantly of transporters, by coding a chloride channel. The gating mechanism of ABC proteins has been characterized by the ATP Switch model in terms cycles of dimer formation and dissociation linked to ATP binding and hydrolysis, respectively. It would be of interest to assess the extent that Cystic Fibrosis Transmembrane Conductance Regulator (CFTR, a functional channel, fits the ATP Switch model for ABC transporters. Additional transporter mechanisms, namely those of Pgp and HlyB, are discussed for perspective. Literature search of databases selected key references in comparing and contrasting the gating mechanism. CFTR is a functional chloride channel facilitating transmembrane anion flow down electrochemical gradients. A dysfunctional CFTR protein results in cystic fibrosis, a fatal pleiotropic disease currently managed symptomatically. Understanding the gating mechanism will help target drug development aimed at alleviating and curing the disease.

  8. Kaempferol suppresses lipid accumulation in macrophages through the downregulation of cluster of differentiation 36 and the upregulation of scavenger receptor class B type I and ATP-binding cassette transporters A1 and G1.

    Science.gov (United States)

    Li, Xiu-Ying; Kong, Ling-Xi; Li, Juan; He, Hai-Xia; Zhou, Yuan-Da

    2013-02-01

    The accumulation of foam cells in atherosclerotic lesions is a hallmark of early-stage atherosclerosis. Kaempferol has been shown to inhibit oxidized low-density lipoprotein (oxLDL) uptake by macrophages; however, the underlying molecular mechanisms are not yet fully investigated. In this study, we shown that treatment with kaempferol markedly suppresses oxLDL-induced macrophage foam cell formation, which occurs due to a decrease in lipid accumulation and an increase in cholesterol efflux from THP-1-derived macrophages. Additionally, the kaempferol treatment of macrophages led to the downregulation of cluster of differentiation 36 (CD36) protein levels, the upregulation of ATP-binding cassette (ABC) transporter A1 (ABCA1), scavenger receptor class B type I (SR-BI) and ABCG1 protein levels, while no effects on scavenger receptor A (SR-A) expression were observed. Kaempferol had similar effects on the mRNA and protein expression of ABCA1, SR-BI, SR-A, CD36 and ABCG1. The reduced CD36 expression following kaempferol treatment involved the inhibition of c-Jun-activator protein-1 (AP-1) nuclear translocation. The inhibition of AP-1 using the inhibitor, SP600125, confirmed this involvement, as the AP-1 inhibition significantly augmented the kaempferol-induced reduction in CD36 expression. Accordingly, the kaempferol-mediated suppression of lipid accumulation in macrophages was also augmented by SP600125. The increased expression of ABCA1, SR-BI and ABCG1 following kaempferol treatment was accompanied by the enhanced protein expression of heme oxygenase-1 (HO-1). This increase was reversed following the knockdown of the HO-1 gene using small hairpin RNA (shRNA). Moreover, the kaempferol-mediated attenuation of lipid accumulation and the promotion of cholesterol efflux was also inhibited by HO-1 shRNA. In conclusion, the c-Jun-AP‑1-dependent downregulation of CD36 and the HO-1-dependent upregulation of ABCG1, SR-BI and ABCA1 may mediate the beneficial effects of

  9. Struktur von ABCE1

    OpenAIRE

    Karcher, Annette

    2007-01-01

    ABCE1 ist ein Mitglied der ATP Binding Cassette (ABC) Superfamilie. ABC Proteine binden und hydrolysieren ATP und verändern dabei ihre Konformation. Dadurch können sie mechanochemische Arbeit leisten. Durch drei zusätzliche Domänen unterscheidet sich ABCE1 von allen bislang bekannten und charakterisierten Mitgliedern dieser Familie. Neben den ATP-bindenden Regionen enthält ABCE1 eine cysteinreiche, N-terminale Domäne, welche zwei Eisen-Schwefel-Cluster bindet. Diese Domäne hat hohe s...

  10. Advances in research of ATP-binding cassette transporters in drug resistance mechanisms of intractable epilepsy%ATP结合盒式蛋白在难治性癫(痫)耐药性机制的研究进展

    Institute of Scientific and Technical Information of China (English)

    付帅

    2014-01-01

    Epilepsy is one of the common diseases in the nervous system with its complicated pathogenesis still remains unknown.The drug resistance mechanism of intractable epilepsy has always been a key point in the research of neuroscience.A possible cause for the drug resistance is the over expression of efflux drug transporters,e.g.ATP-binding cassette transporters,which may decrease extracellular antiepileptic drugs levels in brains of intractable epilepsy patients.ATP-binding cassette transporters are super family of transporter proteins that require ATP hydrolysis for the transport of substrates across membranes,including P-glycoprotein,multidrug resistance-associated protein,major vault protein and breast cancer resistance associated protein.They are major impediment for the AED successful treatment of many forms of refractory epilepsy in human.This paper reviews the research progress on over-expression of ATP-binding cassette transporters and mechanism of drug resistance in intractable epilepsy.%难治性癫(痫)因其耐药机制的复杂性,迄今尚未清楚,目前探究其对抗癫(痫)药物的多重耐药性的一大热点是外流性药物转运蛋白.ATP结合盒式蛋白是外流性药物转运蛋白的代表,其中包括P糖蛋白、多药耐药蛋白、穹窿体主蛋白、乳腺癌耐药蛋白等,它们可以决定抗癫(痫)药物能否有效地作用于癫(痫)部位,而难治性癫(痫)患者对这些蛋白的高表达普遍存在,但是否与疾病耐药性相关仍需进一步探讨.该文从癫(痫)患者的ATP结合盒式蛋白高表达原因和蛋白对药物转运的作用机制方面对患者耐药性影响方面作一综述.

  11. Genome-wide identification and evolution of ATP-binding cassette transporters in the ciliate Tetrahymena thermophila: A case of functional divergence in a multigene family

    Directory of Open Access Journals (Sweden)

    Yuan Dongxia

    2010-10-01

    Full Text Available Abstract Background In eukaryotes, ABC transporters that utilize the energy of ATP hydrolysis to expel cellular substrates into the environment are responsible for most of the efflux from cells. Many members of the superfamily of ABC transporters have been linked with resistance to multiple drugs or toxins. Owing to their medical and toxicological importance, members of the ABC superfamily have been studied in several model organisms and warrant examination in newly sequenced genomes. Results A total of 165 ABC transporter genes, constituting a highly expanded superfamily relative to its size in other eukaryotes, were identified in the macronuclear genome of the ciliate Tetrahymena thermophila. Based on ortholog comparisons, phylogenetic topologies and intron characterizations, each highly expanded ABC transporter family of T. thermophila was classified into several distinct groups, and hypotheses about their evolutionary relationships are presented. A comprehensive microarray analysis revealed divergent expression patterns among the members of the ABC transporter superfamily during different states of physiology and development. Many of the relatively recently formed duplicate pairs within individual ABC transporter families exhibit significantly different expression patterns. Further analysis showed that multiple mechanisms have led to functional divergence that is responsible for the preservation of duplicated genes. Conclusion Gene duplications have resulted in an extensive expansion of the superfamily of ABC transporters in the Tetrahymena genome, making it the largest example of its kind reported in any organism to date. Multiple independent duplications and subsequent divergence contributed to the formation of different families of ABC transporter genes. Many of the members within a gene family exhibit different expression patterns. The combination of gene duplication followed by both sequence divergence and acquisition of new patterns of

  12. ABC transporter architecture and regulatory roles of accessory domains

    NARCIS (Netherlands)

    Biemans-Oldehinkel, E; Doeven, MK; Poolman, B

    2006-01-01

    We present an overview of the architecture of ATP-binding cassette (ABC) transporters and dissect the systems in core and accessory domains. The ABC transporter core is formed by the transmembrane domains (TMDs) and the nucleotide binding domains (NBDs) that constitute the actual translocator. The a

  13. ATP Binding Cassette Transporter ABCA7 Regulates NKT Cell Development and Function by Controlling CD1d Expression and Lipid Raft Content

    Science.gov (United States)

    Nowyhed, Heba N.; Chandra, Shilpi; Kiosses, William; Marcovecchio, Paola; Andary, Farah; Zhao, Meng; Fitzgerald, Michael L.; Kronenberg, Mitchell; Hedrick, Catherine C.

    2017-01-01

    ABCA7 is an ABC transporter expressed on the plasma membrane, and actively exports phospholipid complexes from the cytoplasmic to the exocytoplasmic leaflet of membranes. Invariant NKT (iNKT) cells are a subpopulation of T lymphocytes that recognize glycolipid antigens in the context of CD1d-mediated antigen presentation. In this study, we demonstrate that ABCA7 regulates the development of NKT cells in a cell-extrinsic manner. We found that in Abca7−/− mice there is reduced expression of CD1d accompanied by an alteration in lipid raft content on the plasma membrane of thymocytes and antigen presenting cells. Together, these alterations caused by absence of ABCA7 negatively affect NKT cell development and function. PMID:28091533

  14. 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 v

  15. 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 o

  16. The power stroke driven by ATP binding in CFTR as studied by molecular dynamics simulations.

    Science.gov (United States)

    Furukawa-Hagiya, Tomoka; Furuta, Tadaomi; Chiba, Shuntaro; Sohma, Yoshiro; Sakurai, Minoru

    2013-01-10

    Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel belonging to the ATP binding cassette (ABC) protein superfamily. Currently, it remains unclear how ATP binding causes the opening of the channel gate at the molecular level. To clarify this mechanism, we first constructed an atomic model of the inward-facing CFTR using the X-ray structures of other ABC proteins. Molecular dynamics (MD) simulations were then performed to explore the structure and dynamics of the inward-facing CFTR in a membrane environment. In the MgATP-bound state, two nucleotide-binding domains (NBDs) formed a head-to-tail type of dimer, in which the ATP molecules were sandwiched between the Walker A and signature motifs. Alternatively, one of the final MD structures in the apo state was similar to that of a "closed-apo" conformation found in the X-ray analysis of ATP-free MsbA. Principal component analysis for the MD trajectory indicated that NBD dimerization causes significant structural and dynamical changes in the transmembrane domains (TMDs), which is likely indicative of the formation of a chloride ion access path. This study suggests that the free energy gain from ATP binding acts as a driving force not only for NBD dimerization but also for NBD-TMD concerted motions.

  17. An attenuated mutant of the Rv1747 ATP-binding cassette transporter of Mycobacterium tuberculosis and a mutant of its cognate kinase, PknF, show increased expression of the efflux pump-related iniBAC operon

    Science.gov (United States)

    Spivey, Vicky L; Whalan, Rachael H; Hirst, Elizabeth M A; Smerdon, Stephen J; Buxton, Roger S

    2013-01-01

    The ATP-binding cassette transporter Rv1747 is required for the growth of Mycobacterium tuberculosis in mice and in macrophages. Its structure suggests it is an exporter. Rv1747 forms a two-gene operon with pknF coding for the serine/threonine protein kinase PknF, which positively modulates the function of the transporter. We show that deletion of Rv1747 or pknF results in a number of transcriptional changes which could be complemented by the wild type allele, most significantly up-regulation of the iniBAC genes. This operon is inducible by isoniazid and ethambutol and by a broad range of inhibitors of cell wall biosynthesis and is required for efflux pump functioning. However, neither the Rv1747 or pknF mutant showed increased susceptibility to a range of drugs and cell wall stress reagents including isoniazid and ethambutol, cell wall structure and cell division appear normal by electron microscopy, and no differences in lipoarabinomannan were found. Transcription from the pknF promoter was not induced by a range of stress reagents. We conclude that the loss of Rv1747 affects cell wall biosynthesis leading to the production of intermediates that cause induction of iniBAC transcription and implicates it in exporting a component of the cell wall, which is necessary for virulence. PMID:23915284

  18. The bovine ATP-binding cassette transporter ABCG2 Tyr581Ser single-nucleotide polymorphism increases milk secretion of the fluoroquinolone danofloxacin.

    Science.gov (United States)

    Otero, Jon A; Real, Rebeca; de la Fuente, Álvaro; Prieto, Julio G; Marqués, Margarita; Álvarez, Ana I; Merino, Gracia

    2013-03-01

    The bovine adenosine triphosphate-binding cassette transporter G2 (ABCG2/breast cancer resistance protein) polymorphism Tyr581Ser (Y581S) has recently been shown to increase in vitro transepithelial transport of antibiotics. Since this transporter has been extensively related to the active secretion of drugs into milk, the potential in vivo effect of this polymorphism on secretion of xenobiotics in livestock could have striking consequences for milk production, the dairy industry, and public health. Our purpose was to study the in vivo effect of this polymorphism on the secretion of danofloxacin, a widely used veterinary antibiotic, into milk. Danofloxacin (1.25 mg/kg) was administered to six Y/Y 581 homozygous and six Y/S 581 heterozygous lactating cows, and plasma and milk samples were collected and analyzed by high-performance liquid chromatography. No differences were found in the pharmacokinetic parameters of danofloxacin in plasma between the two groups of animals. In contrast, Y/S heterozygous cows showed a 2-fold increase in danofloxacin levels in milk. In addition, the pharmacokinetic elimination parameters, mean residence time and elimination half-life, were significantly lower in the milk of the animals carrying the Y/S polymorphism. These in vivo results are in agreement with our previously published in vitro data, which showed a greater capacity of the S581 variant in accumulation assays, and demonstrate, for the first time, an important effect of the Y581S single-nucleotide polymorphism on antibiotic secretion into cow milk. These findings could be extended to other ABCG2 substrates, and may be relevant for the treatment of mastitis and for the design of accurate and novel strategies to handle milk residues.

  19. On the role of the two extracytoplasmic substrate-binding domains in the ABC transporter OpuA

    NARCIS (Netherlands)

    Biemans-Oldehinkel, E; Poolman, B

    2003-01-01

    Members of two transporter families of the ATP-binding cassette (ABC) superfamily use two or even four extracytoplasmic substrate-binding domains (SBDs) for transport. We report on the role of the two SBDs in the translocation cycle of the ABC transporter OpuA from Lactococcus lactis. Heterooligomer

  20. Binding of PDZ-RhoGEF to ATP-binding cassette transporter A1 (ABCA1) induces cholesterol efflux through RhoA activation and prevention of transporter degradation.

    Science.gov (United States)

    Okuhira, Keiichiro; Fitzgerald, Michael L; Tamehiro, Norimasa; Ohoka, Nobumichi; Suzuki, Kazuhiro; Sawada, Jun-ichi; Naito, Mikihiko; Nishimaki-Mogami, Tomoko

    2010-05-21

    ATP-binding cassette transporter A1 (ABCA1)-mediated lipid efflux to apolipoprotein A1 (apoA-I) initiates the biogenesis of high density lipoprotein. Here we show that the Rho guanine nucleotide exchange factors PDZ-RhoGEF and LARG bind to the C terminus of ABCA1 by a PDZ-PDZ interaction and prevent ABCA1 protein degradation by activating RhoA. ABCA1 is a protein with a short half-life, and apoA-I stabilizes ABCA1 protein; however, depletion of PDZ-RhoGEF/LARG by RNA interference suppressed the apoA-I stabilization of ABCA1 protein in human primary fibroblasts. Exogenous PDZ-RhoGEF expression activated RhoA and increased ABCA1 protein levels and cholesterol efflux activity. Likewise, forced expression of a constitutively active RhoA mutant significantly increased ABCA1 protein levels, whereas a dominant negative RhoA mutant decreased them. The constitutively active RhoA retarded ABCA1 degradation, thus accounting for its ability to increase ABCA1 protein. Moreover, stimulation with apoA-I transiently activated RhoA, and the pharmacological inhibition of RhoA or the dominant negative RhoA blocked the ability of apoA-I to stabilize ABCA1. Finally, depletion of RhoA or RhoGEFs/RhoA reduces the cholesterol efflux when transcriptional regulation via PPARgamma is eliminated. Taken together, our results have identified a novel physical and functional interaction between ABCA1 and PDZ-RhoGEF/LARG, which activates RhoA, resulting in ABCA1 stabilization and cholesterol efflux activity.

  1. Brucella abortus mutants lacking ATP-binding cassette transporter proteins are highly attenuated in virulence and confer protective immunity against virulent B. abortus challenge in BALB/c mice.

    Science.gov (United States)

    Truong, Quang Lam; Cho, Youngjae; Park, Soyeon; Park, Bo-Kyoung; Hahn, Tae-Wook

    2016-06-01

    Brucella abortus RB51 is an attenuated vaccine strain that has been most frequently used for bovine brucellosis. Although it is known to provide good protection in cattle, it still has some drawbacks including resistance to rifampicin, residual virulence and pathogenicity in humans. Thus, there has been a continuous interest on new safe and effective bovine vaccine candidates. In the present study, we have constructed unmarked mutants by deleting singly cydD and cydC genes, which encode ATP-binding cassette transporter proteins, from the chromosome of the virulent Brucella abortus isolate from Korean cow (referred to as IVK15). Both IVK15ΔcydD and ΔcydC mutants showed increased sensitivity to metal ions, hydrogen peroxide and acidic pH, which are mimic to intracellular environment during host infection. Additionally, the mutants exhibited a significant growth defect in RAW264.7 cells and greatly attenuated in mice. Vaccination of mice with either IVK15ΔcydC or IVK15ΔcydD mutant could elicit an anti-Brucella specific immunoglobulin G (IgG) and IgG subclass responses as well as enhance the secretion of interferon-gamma, and provided better protection against challenge with B. abortus strain 2308 than with the commercial B. abortus strain RB51 vaccine. Collectively, these results suggest that both IVK15ΔcydC and IVK15ΔcydD mutants could be an attenuated vaccine candidate against B. abortus.

  2. 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 secre

  3. Lipid dependence of ABC transporter localization and function

    NARCIS (Netherlands)

    Klappe, Karin; Hummel, Ina; Hoekstra, Dick; Kok, Jan Willem

    2009-01-01

    Lipid rafts have been implicated in many cellular functions, including protein and lipid transport and signal transduction. ATP-binding cassette (ABC) transporters have also been localized in these membrane domains. In this review the evidence for this specific localization will be evaluated and dis

  4. Cystic fibrosis transmembrane conductance regulator: a chloride channel gated by ATP binding and hydrolysis.

    Science.gov (United States)

    Bompadre, Silvia G; Hwang, Tzyh-Chang

    2007-08-25

    The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that belongs to the ATP-binding cassette (ABC) transporter superfamily. Defective function of CFTR is responsible for cystic fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasian populations. The disease is manifested in defective chloride transport across the epithelial cells in various tissues. To date, more than 1400 different mutations have been identified as CF-associated. CFTR is regulated by phosphorylation in its regulatory (R) domain, and gated by ATP binding and hydrolysis at its two nucleotide-binding domains (NBD1 and NBD2). Recent studies reveal that the NBDs of CFTR may dimerize as observed in other ABC proteins. Upon dimerization of CFTR's two NBDs, in a head-to-tail configuration, the two ATP-binding pockets (ABP1 and ABP2) are formed by the canonical Walker A and B motifs from one NBD and the signature sequence from the partner NBD. Mutations of the amino acids that interact with ATP reveal that the two ABPs play distinct roles in controlling ATP-dependent gating of CFTR. It was proposed that binding of ATP to the ABP2, which is formed by the Walker A and B in NBD2 and the signature sequence in NBD1, is critical for catalyzing channel opening. While binding of ATP to the ABP1 alone may not increase the opening rate, it does contribute to the stabilization of the open channel conformation. Several disease-associated mutations of the CFTR channel are characterized by gating defects. Understanding how CFTR's two NBDs work together to gate the channel could provide considerable mechanistic information for future pharmacological studies, which could pave the way for tailored drug design for therapeutical interventions in CF.

  5. Functional reconstitution and osmoregulatory properties of the ProU ABC transporter from Escherichia coli

    NARCIS (Netherlands)

    Gul, Nadia; Poolman, Bert

    2013-01-01

    The ATP-binding cassette (ABC) transporter ProU from Escherichia coli translocates a wide range of compatible solutes and contributes to the regulation of cell volume, which is particularly important when the osmolality of the environment fluctuates. We have purified the components of ProU, i.e., th

  6. Are lipid rafts involved in ABC transporter-mediated drug resistance of tumor cells?

    NARCIS (Netherlands)

    Kok, Jan Willem; Klappe, Karin; Hummel, Ina; Kroesen, Bart-Jan; Sietsma, Hannie; Meszaros, Peter

    2008-01-01

    Since their discovery, lipid rafts have been implicated in several cellular functions, including protein transport in polarized cells and signal transduction. Also in multidrug resistance lipid rafts may be important with regard to the localization of ATP-binding cassette (ABC) transporters in these

  7. Beauvericin counteracted multi-drug resistant Candida albicans by blocking ABC transporters

    DEFF Research Database (Denmark)

    Tong, Yaojun; Liu, Mei; Zhang, Yu

    2016-01-01

    screening and whole-cell based mechanism study, identified a natural product, beauvericin (BEA) as a drug efflux pump modulator, which can reverse the multi-drug resistant phenotype of Candida albicans by specifically blocking the ATP-binding cassette (ABC) transporters; meantime, BEA alone has fungicidal...

  8. 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 transp

  9. 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 onl...

  10. Role of ABC transporters in cancer chemotherapy

    Institute of Scientific and Technical Information of China (English)

    Yue-Li Sun; Atish Patel; Priyank Kumar; Zhe-Sheng Chen

    2012-01-01

    Multidrug resistance (MDR) in cancer cells can significantly attenuate the response to chemotherapy and increase the likelihood of mortality.The major mechanism involved in conferring MDR is the overexpression of ATP-binding cassette (ABC) transporters,which can increase efflux of drugs from cancer cells,thereby decreasing intracellular drug concentration.Modulators of ABC transporters have the potential to augment the efficacy of anticancer drugs.This editorial highlights some major findings related to ABC transporters and current strategies to overcome MDR.

  11. Cystathionine beta-Synthase (CBS) Domains 1 and 2 Fulfill Different Roles in Ionic Strength Sensing of the ATP-binding Cassette (ABC) Transporter OpuA

    NARCIS (Netherlands)

    Karasawa, Akira; Erkens, Guus B.; Berntsson, Ronnie P. -A.; Otten, Renee; Schuurman-Wolters, Gea K.; Mulder, Frans A. A.; Poolman, Bert

    2011-01-01

    The cystathionine beta-synthase module of OpuA in conjunction with an anionic membrane surface acts as a sensor of internal ionic strength, which allows the protein to respond to osmotic stress. We now show by chemical modification and cross-linking studies that CBS2-CBS2 interface residues are crit

  12. Biochemical evidence for the presence of two α-glucoside ABC-transport systems in the hyperthermophilic archaeon Pyrococcus furiosus

    NARCIS (Netherlands)

    Koning, Sonja M.; Konings, Wil N.; Driessen, Arnold J.M.

    2002-01-01

    The hyperthermophilic archaeon Pyrococcus furiosus can utilize different carbohydrates, such as starch, maltose and trehalose. Uptake of α-glucosides is mediated by two different, binding protein-dependent, ATP-binding cassette (ABC)-type transport systems. The maltose transporter also transports tr

  13. 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 expressio

  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; 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...

  15. 三磷酸腺苷结合盒转运体A1在巨噬细胞胆固醇流出中的作用%Effects of ATP binding cassette transporter A1 on cholesterol efflux in macrophages

    Institute of Scientific and Technical Information of China (English)

    唐朝克; 严鹏科; 杨永宗

    2003-01-01

    Tangier disease is caused by mutations in ATP binding cassette transporter AI( ABCA1).ABCA1 interacts with lipid-free apolipoproteins, promoting phospholipid and cholesterol ettlux fzom cells and giving rise to HDL particles. ABCA1 may act as a phospholipid translocase facilitating phospholipid binding to apoA-Ⅰ. ABCA1 gene expression is upregulated in cholesterol-loaded cells as a result of activation of IXR/RXR- mediated gene transcription. LXR and RXR coordinately induce a battery of genes mediating cellular cholesterol efllux, centripetal cholesterol tramport, and cholesterol excretion in bile. Small- molecule activators of LXR/RXR or other stimulators of macrophage or intestinal cholesterol efl]ux hold great promise as future treat-ments for atherosclerosis.

  16. Equilibrated Atomic Models of Outward-Facing P-glycoprotein and Effect of ATP Binding on Structural Dynamics

    Science.gov (United States)

    Pan, Lurong; Aller, Stephen G.

    2015-01-01

    P-glycoprotein (Pgp) is an ATP-binding cassette (ABC) transporter that alternates between inward- and outward-facing conformations to capture and force substrates out of cells like a peristaltic pump. The high degree of similarity in outward-facing structures across evolution of ABC transporters allowed construction of a high-confidence outward-facing Pgp atomic model based on crystal structures of outward-facing Sav1866 and inward-facing Pgp. The model adhered to previous experimentally determined secondary- and tertiary- configurations during all-atom molecular dynamics simulations in the presence or absence of MgATP. Three long lasting (>100 ns) meta-stable states were apparent in the presence of MgATP revealing new insights into alternating access. The two ATP-binding pockets are highly asymmetric resulting in differential control of overall structural dynamics and allosteric regulation of the drug-binding pocket. Equilibrated Pgp has a considerably different electrostatic profile compared to Sav1866 that implicates significant kinetic and thermodynamic differences in transport mechanisms. PMID:25600711

  17. Conservation and distribution of the benzalkonium chloride resistance cassette bcrABC in Listeria monocytogenes.

    Science.gov (United States)

    Dutta, Vikrant; Elhanafi, Driss; Kathariou, Sophia

    2013-10-01

    Analysis of a panel of 116 Listeria monocytogenes strains of diverse serotypes and sources (clinical, environment of food processing plants, and food) revealed that all but one of the 71 benzalkonium chloride-resistant (BC(r)) isolates harbored bcrABC, previously identified on a large plasmid (pLM80) of the 1998-1999 hot dog outbreak strain H7858. In contrast, bcrABC was not detected among BC-susceptible (BC(s)) isolates. The bcrABC sequences were highly conserved among strains of different serotypes, but variability was noted in sequences flanking bcrABC. The majority of the BC(r) isolates had either the pLM80-type of organization of the bcrABC region or appeared to harbor bcrABC on the chromosome, adjacent to novel sequences. Transcription of bcrABC was induced by BC (10 μg/ml) in strains of different serotypes and diverse bcrABC region organization. These findings reveal widespread dissemination of bcrABC across BC(r) L. monocytogenes strains regardless of serotype and source, while also suggesting possible mechanisms of bcrABC dissemination across L. monocytogenes genomes.

  18. Mitochondrial ABC transporters.

    Science.gov (United States)

    Lill, R; Kispal, G

    2001-01-01

    In contrast to bacteria, mitochondria contain only a few ATP binding cassette (ABC) transporters in their inner membrane. The known mitochondrial ABC proteins fall into two major classes that, in the yeast Saccharomyces cerevisiae, are represented by the half-transporter Atm1p and the two closely homologous proteins Mdl1p and Mdl2p. In humans two Atm1p orthologues (ABC7 and MTABC3) and two proteins homologous to Mdll/2p have been localized to mitochondria. The Atm1p-like proteins perform an important function in mitochondrial iron homeostasis and in the maturation of Fe/S proteins in the cytosol. Mutations in ABC7 are causative of hereditary X-linked sideroblastic anemia and cerebellar ataxia (XLSA/A). MTABC3 may be a candidate gene for the lethal neonatal syndrome. The function of the mitochondrial Mdl1/2p-like proteins is not clear at present with the notable exception of murine ABC-me that may transport intermediates of heme biosynthesis from the matrix to the cytosol in erythroid tissues.

  19. Coupled ATPase-adenylate kinase activity in ABC transporters

    Science.gov (United States)

    Kaur, Hundeep; Lakatos-Karoly, Andrea; Vogel, Ramona; Nöll, Anne; Tampé, Robert; Glaubitz, Clemens

    2016-01-01

    ATP-binding cassette (ABC) transporters, a superfamily of integral membrane proteins, catalyse the translocation of substrates across the cellular membrane by ATP hydrolysis. Here we demonstrate by nucleotide turnover and binding studies based on 31P solid-state NMR spectroscopy that the ABC exporter and lipid A flippase MsbA can couple ATP hydrolysis to an adenylate kinase activity, where ADP is converted into AMP and ATP. Single-point mutations reveal that both ATPase and adenylate kinase mechanisms are associated with the same conserved motifs of the nucleotide-binding domain. Based on these results, we propose a model for the coupled ATPase-adenylate kinase mechanism, involving the canonical and an additional nucleotide-binding site. We extend these findings to other prokaryotic ABC exporters, namely LmrA and TmrAB, suggesting that the coupled activities are a general feature of ABC exporters. PMID:28004795

  20. ABC Transporters and the Alzheimer's Disease Enigma.

    Science.gov (United States)

    Wolf, Andrea; Bauer, Björn; Hartz, Anika M S

    2012-01-01

    Alzheimer's disease (AD) is considered the "disease of the twenty-first 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Effect of 5-fluorouracil on the expression of ATP-binding cassette superfamily G member 2 in human colon cancer cell SW480%氟尿嘧啶对人结肠癌SW480细胞ABCG2表达的影响

    Institute of Scientific and Technical Information of China (English)

    瞿金妙; 尤捷; 刘海光; 黄奇迪; 郭贵龙

    2013-01-01

    目的 观察氟尿嘧啶(5-FU)对人结肠癌SW480细胞ABCG2表达的影响.方法 用不同药物浓度的5-FU处理SW480细胞,用CCK8法检测5-FU在SW480中的IC50,流式细胞仪检测SW480细胞ABCG2的阳性表达率,RT-PCR检测ABCG2的mRNA在SW480细胞中的表达差异.结果 5-FU对SW480细胞的IC50随着药物浓度的增加而升高(P<0.05).流式细胞仪检测发现,正常SW480细胞(A组)中ABCG2阳性表达率为(6.26±0.86)%;在药物处理48 h后即刻检测时(B组)的阳性表达率下降至(3.43±1.18)%(P<0.05);在药物处理48 h后的第2代细胞检测时(C组)则升高至(12.91±3.42)%(P<0.05).3组ABCG2 mRNA表达趋势与流式细胞仪检测结果的趋势一致.结论 不同浓度的5-FU可以影响人结肠癌SW480细胞ABCG2的表达.%Objective To investigate the effect of 5-fluorouracil (5-FU) on the expression of ATP-binding cassette superfamily G member 2(ABCG2) in human colon cancer cell SW480.Methods SW480 cells were treated with various concentrations of 5-FU.CCK8 assay was utilized to detect the 5-FU IC50 to SW480 cells.Positive expression of ABCG2 was detected by flow cytometry,and mRNA expression of ABCG2 was detected by real time polymerase chain reaction (RT-PCR).Results The 5-FU IC50 to SW480 cells increased as the drug concentration increased(P<0.05).Flow cytometry revealed that positive expression rate of ABCG2 in normal SW480 cells (group A) was (6.26±0.86)%.Immediately after treatment with 5-FU for 48 hours,the positive expression rate of ABCG2 (group B) was (3.43±1.18)%(P<0.05).In the second passage of cells after treatment with 5-FU for 48 hours,the positive expression rate of ABCG2 (group C) was (12.91±3.42)%(P<0.05).The mRNA expression of ABCG2 detected by RT-PCR was in accordance with the results from flow cytometry.Conclusion Expression of ABCG2 in SW480 cells can be affected by various concentrations of 5-FU.

  3. 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

    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......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...... characterization of ABC exporters in Xenopus oocytes. Although the Xenopus oocyte expression system is particularly suitable for expression of membrane proteins and powerful in screening for novel transporter activity, only few examples of successful expression of ABC transporter has been reported. This raises...

  4. 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.

  5. 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.

  6. ABCE1 is a highly conserved RNA silencing suppressor.

    Directory of Open Access Journals (Sweden)

    Kairi Kärblane

    Full Text Available ATP-binding cassette sub-family E member 1 (ABCE1 is a highly conserved protein among eukaryotes and archaea. Recent studies have identified ABCE1 as a ribosome-recycling factor important for translation termination in mammalian cells, yeast and also archaea. Here we report another conserved function of ABCE1. We have previously described AtRLI2, the homolog of ABCE1 in the plant Arabidopsis thaliana, as an endogenous suppressor of RNA silencing. In this study we show that this function is conserved: human ABCE1 is able to suppress RNA silencing in Nicotiana benthamiana plants, in mammalian HEK293 cells and in the worm Caenorhabditis elegans. Using co-immunoprecipitation and mass spectrometry, we found a number of potential ABCE1-interacting proteins that might support its function as an endogenous suppressor of RNA interference. The interactor candidates are associated with epigenetic regulation, transcription, RNA processing and mRNA surveillance. In addition, one of the identified proteins is translin, which together with its binding partner TRAX supports RNA interference.

  7. Effects of ATP-binding cassette exporters on virulence factors in Streptococcus mutans%三磷酸腺苷结合盒外排子对变异链球菌毒力因子影响的研究进展

    Institute of Scientific and Technical Information of China (English)

    曾荟荟; 凌均棨

    2015-01-01

    ABC transporters have been proved to be integral membrane proteins that actively transported a diverse range of substrates across cell membranes. ABC transporters had varied functions, and took part in gene competence, (p)ppGpp accumulation, bacteriocin secretion and immunity in Streptococcus mutans. The structures, functions, mechanisms and inhibitors of the known ABC exporters in Streptococcus mutans were summarized.%三磷酸腺苷结合盒(ABC)转运子是膜蛋白的一部分,透过细胞膜转运各种生物分子,参与多种生理功能。在变异链球菌中,ABC外排子与基因感受态、四(五)磷酸鸟苷[(p)ppGpp]累积、细菌素分泌与免疫密切相关。本文就变异链球菌ABC外排子的结构、生理功能、作用机制和抑制剂作一综述。

  8. ABC multidrug transporters in schistosomes and other parasitic flatworms.

    Science.gov (United States)

    Greenberg, Robert M

    2013-12-01

    Schistosomiasis, a neglected tropical disease affecting hundreds of millions, is caused by parasitic flatworms of the genus Schistosoma. Treatment and control of schistosomiasis relies almost exclusively on a single drug, praziquantel (PZQ), a dangerous situation for a disease of this magnitude. Though PZQ is highly effective overall, it has drawbacks, and reports of worms showing PZQ resistance, either induced in the laboratory or isolated from the field, are disconcerting. Multidrug transporters underlie multidrug resistance (MDR), a phenomenon in which resistance to a single drug is accompanied by unexpected cross-resistance to several structurally unrelated compounds. Some of the best studied multidrug transporters are members of the ancient and very large ATP-binding cassette (ABC) superfamily of efflux transporters. ABC multidrug transporters such as P-glycoprotein (Pgp; ABCB1) are also associated with drug resistance in parasites, including helminths such as schistosomes. In addition to their association with drug resistance, however, ABC transporters also function in a wide variety of physiological processes in metazoans. In this review, we examine recent studies that help define the role of schistosome ABC transporters in regulating drug susceptibility, and in normal schistosome physiology, including reproduction and excretory activity. We postulate that schistosome ABC transporters could be useful targets for compounds that enhance the effectiveness of current therapeutics as well as for agents that act as antischistosomals on their own.

  9. A PhoPQ-Regulated ABC Transporter System Exports Tetracycline in Pseudomonas aeruginosa.

    Science.gov (United States)

    Chen, Lin; Duan, Kangmin

    2016-05-01

    Pseudomonas aeruginosa is an important human pathogen whose infections are difficult to treat due to its high intrinsic resistance to many antibiotics. Here, we show that the disruption of PA4456, encoding the ATP binding component of a putative ATP-binding cassette (ABC) transporter, increased the bacterium's susceptible to tetracycline and other antibiotics or toxic chemicals. Fluorescence spectroscopy and antibiotic accumulation tests showed that the interruption of the ABC transporter caused increased intracellular accumulation of tetracycline, demonstrating a role of the ABC transporter in tetracycline expulsion. Site-directed mutagenesis proved that the conserved residues of E170 in the Walker B motif and H203 in the H-loop, which are important for ATP hydrolysis, were essential for the function of PA4456. Through a genome-wide search, the PhoPQ two-component system was identified as a regulator of the computationally predicted PA4456-4452 operon that encodes the ABC transporter system. A >5-fold increase of the expression of this operon was observed in the phoQ mutant. The results obtained also show that the expression of the phzA1B1C1D1E1 operon and the production of pyocyanin were significantly higher in the ABC transporter mutant, signifying a connection between the ABC transporter and pyocyanin production. These results indicated that the PhoPQ-regulated ABC transporter is associated with intrinsic resistance to antibiotics and other adverse compounds in P. aeruginosa, probably by extruding them out of the cell.

  10. Enantioselective Induction of a Glutathione-S-Transferase, a Glutathione Transporter and an ABC Transporter in Maize by Metolachlor and Its (S)-Isomer

    OpenAIRE

    Sen Pang; Zhaojin Ran; Zhiqian Liu; Xiaoyu Song; Liusheng Duan; Xuefeng Li; Chengju Wang

    2012-01-01

    The metabolism of chiral herbicides in plants remains poorly understood. Glutathione conjugation reactions are one of the principal mechanisms that plants utilize to detoxify xenobiotics. The induction by rac- and S-metolachlor of 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 of rac- and S-...

  11. Functionally Relevant Residues of Cdr1p: A Multidrug ABC Transporter of Human Pathogenic Candida albicans

    Directory of Open Access Journals (Sweden)

    Rajendra Prasad

    2011-01-01

    Full Text Available Reduced intracellular accumulation of drugs (due to rapid efflux mediated by the efflux pump proteins belonging to ABC (ATP Binding Cassette and MFS (Major Facilitators superfamily is one of the most common strategies adopted by multidrug resistance (MDR pathogenic yeasts. To combat MDR, it is essential to understand the structure and function of these transporters so that inhibitors/modulators to these can be developed. The sequence alignments of the ABC transporters reveal selective divergence within much conserved domains of Nucleotide-Binding Domains (NBDs which is unique to all fungal transporters. Recently, the role of conserved but divergent residues of Candida Drug Resistance 1 (CDR1, an ABC drug transporter of human pathogenic Candida albicans, has been examined with regard to ATP binding and hydrolysis. In this paper, we focus on some of the recent advances on the relevance of divergent and conserved amino acids of CaCdr1p and also discuss as to how drug interacts with Trans Membrane Domains (TMDs residues for its extrusion from MDR cells.

  12. 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

    Listeria monocytogenes may persist for long periods in food processing environments. In some instances, this may be due to aggregation or biofilm formation. To investigate the mechanism controlling biofilm formation in the food-borne pathogen L. monocytogenes, we characterized LM-49, a mutant...... 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......-transporter permease) presented in the sequenced strain L. monocytogenes str. 4b F2365. This disrupted gene, denoted lm.G_1771, encoded a protein with 10 transmembrane helixes. The revertant, LM-49RE, was obtained by replacing lm.G_1771::Tn917 with lm.G_1771 via homologous recombination. We found that LM-49RE formed...

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

    Directory of Open Access Journals (Sweden)

    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.

  14. ABC转运蛋白与巴西橡胶树产胶代谢%ABC Transporters and the Latex Regeneration Metabolism of Hevea brasiliensis

    Institute of Scientific and Technical Information of China (English)

    聂智毅; 黎瑜; 曾日中

    2013-01-01

    ABC转运蛋白(ATP Binding Cassette transporter)是目前已知最大、功能最广泛的蛋白家族之一。大多数ABC转运蛋白都能利用水解ATP释放的能量直接转运底物。许多研究结果显示,植物ABC转运蛋白在各种代谢产物的跨膜转运中起着重要作用。橡胶的产胶代谢是一种典型的植物类异戊二烯次生代谢,是影响橡胶产量的首要因素。相关实验结果显示, ABC转运蛋白可能参与橡胶树产胶代谢。本文介绍了模式植物拟南芥中的ABC转运蛋白研究进展,并对ABC转运蛋白与橡胶树产胶代谢的关系进行讨论。%ATP Binding Cassette transporters (ABC transporters) constitute the largest protein family with the most variety of functions. Most ABC transporters can utilize the energy of ATP hydrolysis to transport substances, and many researches reveal that ABC transporters play important roles in translocation of plant metabolites across membranes. Latex regeneration metabolism of Hevea brasiliensis is a typical of plant isoprenoid secondary metabolism and is the primary factor affecting rubber production. Researches reveal that ABC-transporters may be involved in the latex regeneration metabolism of Hevea brasiliensis. Base on the new advances in ABC-transporters in A rabidopsis thaliana, the relation between ABC-transporters and latex regeneration of Hevea brasiliensis was discussed in the review.

  15. ω-carboxyl Like Linoleic Acid Oxides Promoting the Expression of ATP-binding Cassette Transporter A1 (ABCA1)%ω-羧基样亚油酸氧化物促进ATP结合盒转运子A1(ABCA1)表达

    Institute of Scientific and Technical Information of China (English)

    马艳华; 刘庆平; 娜琴; 苑红; 扈瑞平

    2015-01-01

    ω-羧基样亚油酸氧化物(7-KC-9-COOH)是由Cu2+氧化低密度脂蛋白(oxLDL)中得到的负性胆固醇氧化物.研究其对ATP结合盒(ABC)转运子超家族成员ABCA1表达的调控作用,并探讨其对高密度脂蛋白(HDL)介导的胆固醇流出的影响.THP-1单核细胞经佛波酯(PMA)诱导分化为巨噬细胞,化学合成的7-KC-9-COOH以时间梯度孵育细胞,随后采用RTPCR,western blot研究其对ABCA1基因和蛋白水平表达的影响.7-KC-9-COOH显著促进了ABCAl mRNA和蛋白水平表达,其中作用2h效果最为显著,基因水平增加48.6%(*P<0.05),蛋白水平增加285.3%,较空白组升高近3倍(**P<0.01).抑制其上游核转录因子PPARγ与LXRα,其蛋白表达量下降51.2%.ω-COOH亚油酸氧化物7-KC-9-COOH经由PPARγ-LXRα信号通路提高了ABCA1的表达,促进了胆固醇逆转运(RCT)和HDL介导的胆固醇流出.

  16. 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.

  17. 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

    2017-01-01

    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. PMID:28119610

  18. The Nucleotide-Free State of the Multidrug Resistance ABC Transporter LmrA: Sulfhydryl Cross-Linking Supports a Constant Contact, Head-to-Tail Configuration of the Nucleotide-Binding Domains.

    Directory of Open Access Journals (Sweden)

    Peter M Jones

    Full Text Available ABC transporters are integral membrane pumps that are responsible for the import or export of a diverse range of molecules across cell membranes. ABC transporters have been implicated in many phenomena of medical importance, including cystic fibrosis and multidrug resistance in humans. The molecular architecture of ABC transporters comprises two transmembrane domains and two ATP-binding cassettes, or nucleotide-binding domains (NBDs, which are highly conserved and contain motifs that are crucial to ATP binding and hydrolysis. Despite the improved clarity of recent structural, biophysical, and biochemical data, the seemingly simple process of ATP binding and hydrolysis remains controversial, with a major unresolved issue being whether the NBD protomers separate during the catalytic cycle. Here chemical cross-linking data is presented for the bacterial ABC multidrug resistance (MDR transporter LmrA. These indicate that in the absence of nucleotide or substrate, the NBDs come into contact to a significant extent, even at 4°C, where ATPase activity is abrogated. The data are clearly not in accord with an inward-closed conformation akin to that observed in a crystal structure of V. cholerae MsbA. Rather, they suggest a head-to-tail configuration 'sandwich' dimer similar to that observed in crystal structures of nucleotide-bound ABC NBDs. We argue the data are more readily reconciled with the notion that the NBDs are in proximity while undergoing intra-domain motions, than with an NBD 'Switch' mechanism in which the NBD monomers separate in between ATP hydrolysis cycles.

  19. ATP-binding cassette transporter controls leaf surface secretion of anticancer drug components in Catharanthus roseus.

    Science.gov (United States)

    Yu, Fang; De Luca, Vincenzo

    2013-09-24

    The Madagascar periwinkle (Catharanthus roseus) is highly specialized for the biosynthesis of many different monoterpenoid indole alkaloids (MIAs), many of which have powerful biological activities. Such MIAs include the commercially important chemotherapy drugs vinblastine, vincristine, and other synthetic derivatives that are derived from the coupling of catharanthine and vindoline. However, previous studies have shown that biosynthesis of these MIAs involves extensive movement of metabolites between specialized internal leaf cells and the leaf epidermis that require the involvement of unknown secretory processes for mobilizing catharanthine to the leaf surface and vindoline to internal leaf cells. Spatial separation of vindoline and catharanthine provides a clear explanation for the low levels of dimers that accumulate in intact plants. The present work describes the molecular cloning and functional identification of a unique catharanthine transporter (CrTPT2) that is expressed predominantly in the epidermis of young leaves. CrTPT2 gene expression is activated by treatment with catharanthine, and its in planta silencing redistributes catharanthine to increase the levels of catharanthine-vindoline drug dimers in the leaves. Phylogenetic analysis shows that CrTPT2 is closely related to a key transporter involved in cuticle assembly in plants and that may be unique to MIA-producing plant species, where it mediates secretion of alkaloids to the plant surface.

  20. ATP binding cassette transporters modulate both coelenterazine- and D-luciferin- based bioluminescence imaging

    OpenAIRE

    Huang, Ruimin; Vider, Jelena; Serganova, Inna; Blasberg, Ronald G.

    2011-01-01

    Bioluminescence imaging (BLI) of luciferase reporters provides a cost-effective and sensitive means to image biological processes. However, transport of luciferase substrates across the cell membrane does affect BLI-readout-intensity from intact living cells.

  1. Transcriptome-based identification of ABC transporters in the western tarnished plant bug Lygus hesperus.

    Directory of Open Access Journals (Sweden)

    J Joe Hull

    Full Text Available 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 clearance. While ABC transporters have been extensively studied in vertebrates, less is known concerning this superfamily in insects, particularly hemipteran pests. We used RNA-Seq transcriptome sequencing to identify 65 putative ABC transporter sequences (including 36 full-length sequences from the eight ABC subfamilies in the western tarnished plant bug (Lygus hesperus, a polyphagous agricultural pest. Phylogenetic analyses revealed clear orthologous relationships with ABC transporters linked to insecticide/xenobiotic clearance and indicated lineage specific expansion of the L. hesperus ABCG and ABCH subfamilies. The transcriptional profile of 13 LhABCs representative of the ABCA, ABCB, ABCC, ABCG, and ABCH subfamilies was examined across L. hesperus development and within sex-specific adult tissues. All of the transcripts were amplified from both reproductively immature and mature adults and all but LhABCA8 were expressed to some degree in eggs. Expression of LhABCA8 was spatially localized to the testis and temporally timed with male reproductive development, suggesting a potential role in sexual maturation and/or spermatozoa protection. Elevated expression of LhABCC5 in Malpighian tubules suggests a possible role in xenobiotic clearance. Our results provide the first transcriptome-wide analysis of ABC transporters in an agriculturally important hemipteran pest and, because ABC transporters are known to be important mediators of insecticidal resistance, will provide the basis for future biochemical and toxicological studies on the role of this protein family in insecticide resistance in Lygus species.

  2. ABC-F Proteins Mediate Antibiotic Resistance through Ribosomal Protection.

    Science.gov (United States)

    Sharkey, Liam K R; Edwards, Thomas A; O'Neill, Alex J

    2016-03-22

    Members of the ABC-F subfamily of ATP-binding cassette proteins mediate resistance to a broad array of clinically important antibiotic classes that target the ribosome of Gram-positive pathogens. The mechanism by which these proteins act has been a subject of long-standing controversy, with two competing hypotheses each having gained considerable support: antibiotic efflux versus ribosomal protection. Here, we report on studies employing a combination of bacteriological and biochemical techniques to unravel the mechanism of resistance of these proteins, and provide several lines of evidence that together offer clear support to the ribosomal protection hypothesis. Of particular note, we show that addition of purified ABC-F proteins to anin vitrotranslation assay prompts dose-dependent rescue of translation, and demonstrate that such proteins are capable of displacing antibiotic from the ribosomein vitro To our knowledge, these experiments constitute the first direct evidence that ABC-F proteins mediate antibiotic resistance through ribosomal protection.IMPORTANCEAntimicrobial resistance ranks among the greatest threats currently facing human health. Elucidation of the mechanisms by which microorganisms resist the effect of antibiotics is central to understanding the biology of this phenomenon and has the potential to inform the development of new drugs capable of blocking or circumventing resistance. Members of the ABC-F family, which includelsa(A),msr(A),optr(A), andvga(A), collectively yield resistance to a broader range of clinically significant antibiotic classes than any other family of resistance determinants, although their mechanism of action has been controversial since their discovery 25 years ago. Here we present the first direct evidence that proteins of the ABC-F family act to protect the bacterial ribosome from antibiotic-mediated inhibition.

  3. Placental ABC transporters, cellular toxicity and stress in pregnancy.

    Science.gov (United States)

    Aye, Irving L M H; Keelan, Jeffrey A

    2013-04-25

    The human placenta, in addition to its roles as a nutrient transfer and endocrine organ, functions as a selective barrier to protect the fetus against the harmful effects of exogenous and endogenous toxins. Members of the ATP-binding cassette (ABC) family of transport proteins limit the entry of xenobiotics into the fetal circulation via vectorial efflux from the placenta to the maternal circulation. Several members of the ABC family, including proteins from the ABCA, ABCB, ABCC and ABCG subfamilies, have been shown to be functional in the placenta with clinically significant roles in xenobiotic efflux. However, recent findings suggest that these transporters also protect placental tissue by preventing the cellular accumulation of cytotoxic compounds such as lipids, sterols and their derivatives. Such protective functions are likely to be particularly important in pregnancies complicated by inflammatory or oxidative stress, where the generation of toxic metabolites is enhanced. For example, ABC transporters have been shown to protect against the harmful effects of hypoxia and oxidative stress through increased expression and efflux of oxysterols and glutathione conjugated xenobiotics. However, this protective capacity may be diminished in response to the same stressors. Several studies in primary human trophoblast cells and animal models have demonstrated decreased expression and activity of placental ABC transporters with inflammatory, oxidative or metabolic stress. Several clinical studies in pregnancies complicated by inflammatory conditions such as preeclampsia and gestational diabetes support these findings, although further studies are required to determine the clinical relevance of the relationships between placental ABC transporter expression and activity, and placental function in stressed pregnancies. Such studies are necessary to fully understand the consequences of pregnancy disorders on placental function and viability in order to optimise pregnancy

  4. Two molybdate/tungstate ABC transporters that interact very differently with their substrate binding proteins.

    Science.gov (United States)

    Vigonsky, Elena; Ovcharenko, Elena; Lewinson, Oded

    2013-04-02

    In all kingdoms of life, ATP Binding Cassette (ABC) transporters participate in many physiological and pathological processes. Despite the diversity of their functions, they have been considered to operate by a largely conserved mechanism. One deviant is the vitamin B12 transporter BtuCD that has been shown to operate by a distinct mechanism. However, it is unknown if this deviation is an exotic example, perhaps arising from the nature of the transported moiety. Here we compared two ABC importers of identical substrate specificity (molybdate/tungstate), and find that their interactions with their substrate binding proteins are utterly different. One system forms a high-affinity, slow-dissociating complex that is destabilized by nucleotide and substrate binding. The other forms a low-affinity, transient complex that is stabilized by ligands. The results highlight significant mechanistic divergence among ABC transporters, even when they share the same substrate specificity. We propose that these differences are correlated with the different folds of the transmembrane domains of ABC transporters.

  5. Mammalian P4-ATPases and ABC transporters and their role in phospholipid transport.

    Science.gov (United States)

    Coleman, Jonathan A; Quazi, Faraz; Molday, Robert S

    2013-03-01

    Transport of phospholipids across cell membranes plays a key role in a wide variety of biological processes. These include membrane biosynthesis, generation and maintenance of membrane asymmetry, cell and organelle shape determination, phagocytosis, vesicle trafficking, blood coagulation, lipid homeostasis, regulation of membrane protein function, apoptosis, etc. P(4)-ATPases and ATP binding cassette (ABC) transporters are the two principal classes of membrane proteins that actively transport phospholipids across cellular membranes. P(4)-ATPases utilize the energy from ATP hydrolysis to flip aminophospholipids from the exocytoplasmic (extracellular/lumen) to the cytoplasmic leaflet of cell membranes generating membrane lipid asymmetry and lipid imbalance which can induce membrane curvature. Many ABC transporters play crucial roles in lipid homeostasis by actively transporting phospholipids from the cytoplasmic to the exocytoplasmic leaflet of cell membranes or exporting phospholipids to protein acceptors or micelles. Recent studies indicate that some ABC proteins can also transport phospholipids in the opposite direction. The importance of P(4)-ATPases and ABC transporters is evident from the findings that mutations in many of these transporters are responsible for severe human genetic diseases linked to defective phospholipid transport. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.

  6. Toward Determining ATPase Mechanism in ABC Transporters: Development of the Reaction Path–Force Matching QM/MM Method

    Science.gov (United States)

    Zhou, Y.; Ojeda-May, P.; Nagaraju, M.; Pu, J.

    2016-01-01

    Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are ubiquitous ATP-dependent membrane proteins involved in translocations of a wide variety of substrates across cellular membranes. To understand the chemomechanical coupling mechanism as well as functional asymmetry in these systems, a quantitative description of how ABC transporters hydrolyze ATP is needed. Complementary to experimental approaches, computer simulations based on combined quantum mechanical and molecular mechanical (QM/MM) potentials have provided new insights into the catalytic mechanism in ABC transporters. Quantitatively reliable determination of the free energy requirement for enzymatic ATP hydrolysis, however, requires substantial statistical sampling on QM/MM potential. A case study shows that brute force sampling of ab initio QM/MM (AI/MM) potential energy surfaces is computationally impractical for enzyme simulations of ABC transporters. On the other hand, existing semiempirical QM/MM (SE/MM) methods, although affordable for free energy sampling, are unreliable for studying ATP hydrolysis. To close this gap, a multiscale QM/MM approach named reaction path–force matching (RP–FM) has been developed. In RP–FM, specific reaction parameters for a selected SE method are optimized against AI reference data along reaction paths by employing the force matching technique. The feasibility of the method is demonstrated for a proton transfer reaction in the gas phase and in solution. The RP–FM method may offer a general tool for simulating complex enzyme systems such as ABC transporters. PMID:27498639

  7. Cystic fibrosis transmembrane conductance regulator: a chloride channel gated by ATP binding and hydrolysis%囊性纤维化跨膜电导调节体:ATP结合和水解门控Cl-通道

    Institute of Scientific and Technical Information of China (English)

    BOMPADRE; Silvia; G; HWANG; Tzyh-Chang

    2007-01-01

    囊性纤维化跨膜电导调节体(cystic fibrosis transmembrane conductance regulator,CFTR)是一种Cl-通道,属于ATP结合(ATP-binding cassette,ABC)转运体超家族.CFTR功能缺陷是高加索人种中普遍存在的致死性常染色体隐性遗传疾病囊性纤维化(cystic fibrosis,CF)发生的主要原因.这种疾病患者各组织上皮细胞内Cl-转运失调.目前,与CF相关的不同突变超过1 400种.CFTR调节(regulatory,R)域负责调控,核苷酸结合域(nucleotide-binding domains,NBDs)NBD1和NBD2负责ATP结合和水解门控.近期研究发现CFTR的NBDs与其它ABC蛋白一样可以二聚化.二聚化过程中,NBD1和NBD2首-尾相连,一个NBD上的WalkerA和B模块与另一个NBD提供的标签序列(signature sequence)形成ATP结合袋(ATP-binding pockets,ABPs)ABP1和ABP2.ABPs中与ATP结合相关的氨基酸突变实验揭示,ABP1和ABP2在CFTR的ATP依赖门控中发挥不同作用.ABP2由NBD2上的Walk A和B模块与NBD1提供的标签序列形成,它与ATP结合催化通道开放,而ABP1单独与ATP结合不能促进通道开放,只能稳定通道构象.有一些CFTR突变相关疾病的特征就是门控失调,进一步深入研究CFTR的NBD1和NBD2如何通过相互作用而达到通道门控,将为药理学研究提供更多所需的机制信息,有利于为CF治疗的药物设计铺平道路.%The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that belongs to the ATP-binding cassette (ABC) transporter superfamily. Defective function of CFTR is responsible for cystic fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasian populations. The disease is manifested in defective chloride transport across the epithelial cells in various tissues. To date, more than 1400 different mutations have been identified as CF-associated. CFTR is regulated by phosphorylation in its regulatory (R) domain, and gated by ATP binding and hydrolysis at its two nucleotide-binding domains (NBD1

  8. Differential contributions of five ABC transporters to mutidrug resistance, antioxidion and virulence of Beauveria bassiana, an entomopathogenic fungus.

    Science.gov (United States)

    Song, Ting-Ting; Zhao, Jing; Ying, Sheng-Hua; Feng, Ming-Guang

    2013-01-01

    Multidrug resistance (MDR) confers agrochemical compatibility to fungal cells-based mycoinsecticdes but mechanisms involved in MDR remain poorly understood for entomopathogenic fungi, which have been widely applied as biocontrol agents against arthropod pests. Here we characterized the functions of five ATP-binding cassette (ABC) transporters, which were classified to the subfamilies ABC-B (Mdr1), ABC-C (Mrp1) and ABC-G (Pdr1, Pdr2 and Pdr5) and selected from 54 full-size ABC proteins of Beauveria bassiana based on their main domain architecture, membrane topology and transcriptional responses to three antifungal inducers. Disruption of each transporter gene resulted in significant reduction in resistance to four to six of eight fungicides or antifungal drugs tested due to their differences in structure and function. Compared with wild-type and complemented (control) strains, disruption mutants of all the five transporter genes became significantly less tolerant to the oxidants menadione and H₂O₂ based on 22-41% and 10-31% reductions of their effective concentrations required for the suppression of 50% colony growth at 25°C. Under a standardized spray, the killing actions of ΔPdr5 and ΔMrp1 mutants against Spodoptera litura second-instar larvae were delayed by 59% and 33% respectively. However, no significant virulence change was observed in three other delta mutants. Taken together, the examined five ABC transporters contribute differentially to not only the fungal MDR but antioxidant capability, a phenotype rarely associated with ABC efflux pumps in previous reports; at least some of them are required for the full virulence of B. bassiana, thereby affecting the fungal biocontrol potential. Our results indicate that ABC pump-dependent MDR mechanisms exist in entomopathogenic fungi as do in yeasts and human and plant pathogenic fungi.

  9. Differential contributions of five ABC transporters to mutidrug resistance, antioxidion and virulence of Beauveria bassiana, an entomopathogenic fungus.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Song

    Full Text Available Multidrug resistance (MDR confers agrochemical compatibility to fungal cells-based mycoinsecticdes but mechanisms involved in MDR remain poorly understood for entomopathogenic fungi, which have been widely applied as biocontrol agents against arthropod pests. Here we characterized the functions of five ATP-binding cassette (ABC transporters, which were classified to the subfamilies ABC-B (Mdr1, ABC-C (Mrp1 and ABC-G (Pdr1, Pdr2 and Pdr5 and selected from 54 full-size ABC proteins of Beauveria bassiana based on their main domain architecture, membrane topology and transcriptional responses to three antifungal inducers. Disruption of each transporter gene resulted in significant reduction in resistance to four to six of eight fungicides or antifungal drugs tested due to their differences in structure and function. Compared with wild-type and complemented (control strains, disruption mutants of all the five transporter genes became significantly less tolerant to the oxidants menadione and H₂O₂ based on 22-41% and 10-31% reductions of their effective concentrations required for the suppression of 50% colony growth at 25°C. Under a standardized spray, the killing actions of ΔPdr5 and ΔMrp1 mutants against Spodoptera litura second-instar larvae were delayed by 59% and 33% respectively. However, no significant virulence change was observed in three other delta mutants. Taken together, the examined five ABC transporters contribute differentially to not only the fungal MDR but antioxidant capability, a phenotype rarely associated with ABC efflux pumps in previous reports; at least some of them are required for the full virulence of B. bassiana, thereby affecting the fungal biocontrol potential. Our results indicate that ABC pump-dependent MDR mechanisms exist in entomopathogenic fungi as do in yeasts and human and plant pathogenic fungi.

  10. Recent advances regarding the role of ABC subfamily C member 10 (ABCC10) in the efflux of antitumor drugs

    Institute of Scientific and Technical Information of China (English)

    Rishil J. Kathawala; Yi-Jun Wang; Charles R. Ashby Jr; Zhe-Sheng Chen

    2014-01-01

    ABCC10, also known as multidrug-resistant protein 7 (MRP7), is the tenth member of the C subfamily of the ATP-binding cassette (ABC) superfamily. ABCC10 mediates multidrug resistance (MDR) in cancer cells by preventing the intracellular accumulation of certain antitumor drugs. The ABCC10 transporter is a 171-kDa protein that is localized on the basolateral cell membrane. ABCC10 is a broad-specificity transporter of xenobiotics, including antitumor drugs, such as taxanes, epothilone B, vinca alkaloids, and cytarabine, as wel as modulators of the estrogen pathway, such as tamoxifen. In recent years, ABCC10 inhibitors, including cepharanthine, lapatinib, erlotinib, nilotinib, imatinib, sildenafil, and vardenafil, have been reported to overcome ABCC10-mediated MDR. This review discusses some recent and clinically relevant aspects of the ABCC10 drug efflux transporter from the perspective of current chemotherapy, particularly its inhibition by tyrosine kinase inhibitors and phosphodiesterase type 5 inhibitors.

  11. 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

    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.

  12. Cloning and Expression Analysis of a MDR-type ABC Transporter Abundant in Rubber Tree Latex%橡胶树一个胶乳高表达MDR型ABC转运蛋白的克隆与表达研究

    Institute of Scientific and Technical Information of China (English)

    聂智毅; 李波; 白瑞璞; 黎瑜

    2011-01-01

    ABC (ATP-Binding Cassette) transporters constitute the largest protein family with the most variety of functions.They are involved in the excretion, accumulation and the transmembrane transport of plant secondary metabolites.Through screening an ethylene-induced latex SSH cDNA library combined with RACE,one ABC transporter gene EST and its full-length cDNA were obtained, which was 3753 bp with an ORF that encoded a polypeptide of 1251 amino acids.The results showed that the ABC transporter gene had multiple copies in rubber tree genome and was primarily expressed in latex.Under ethylene or jasmonic acid induction,its expression was up-regulated.Base on above analysis, we speculated that the ABC transporter was closely correlated to the transport of rubber biosynthesis metabolites.%ABC转运蛋白(ATP-Binding Cassette)是目前已知最大、功能最广泛的蛋白家族之一,与植物次生代谢物的排泌、积累及跨膜运转密切相关.本研究筛选已构建的乙烯刺激橡胶树胶乳消减文库,克隆了1个ABC转运蛋白基因EST,通过RACE技术获得其全长cDNA序列,该基因开放阅读框(ORF)共3753 bp,编码1251个氨基酸残基.研究表明其在橡胶树基因组中存在多个拷贝,主要在胶乳中表达,且在乙烯或茉莉酸刺激(刺激产胶)条件下上调表达.推测其可能与橡胶生物合成过程中的物质转运密切相关.

  13. ATP Binding Turns Plant Cryptochrome Into an Efficient Natural Photoswitch

    Science.gov (United States)

    Müller, Pavel; Bouly, Jean-Pierre; Hitomi, Kenichi; Balland, Véronique; Getzoff, Elizabeth D.; Ritz, Thorsten; Brettel, Klaus

    2014-06-01

    Cryptochromes are flavoproteins that drive diverse developmental light-responses in plants and participate in the circadian clock in animals. Plant cryptochromes have found application as photoswitches in optogenetics. We have studied effects of pH and ATP on the functionally relevant photoreduction of the oxidized FAD cofactor to the semi-reduced FADH. radical in isolated Arabidopsis cryptochrome 1 by transient absorption spectroscopy on nanosecond to millisecond timescales. In the absence of ATP, the yield of light-induced radicals strongly decreased with increasing pH from 6.5 to 8.5. With ATP present, these yields were significantly higher and virtually pH-independent up to pH 9. Analysis of our data in light of the crystallographic structure suggests that ATP-binding shifts the pKa of aspartic acid D396, the putative proton donor to FAD.-, from ~7.4 to >9, and favours a reaction pathway yielding long-lived aspartate D396-. Its negative charge could trigger conformational changes necessary for signal transduction.

  14. Growth Hormone Receptor Knockdown Sensitizes Human Melanoma Cells to Chemotherapy by Attenuating Expression of ABC Drug Efflux Pumps.

    Science.gov (United States)

    Basu, Reetobrata; Baumgaertel, Nicholas; Wu, Shiyong; Kopchick, John J

    2017-03-14

    Melanoma remains one of the most therapy-resistant forms of human cancer despite recent introductions of highly efficacious targeted therapies. The intrinsic therapy resistance of human melanoma is largely due to abundant expression of a repertoire of xenobiotic efflux pumps of the ATP-binding cassette (ABC) transporter family. Here, we report that GH action is a key mediator of chemotherapeutic resistance in human melanoma cells. We investigated multiple ABC efflux pumps (ABCB1, ABCB5, ABCB8, ABCC1, ABCC2, ABCG1, and ABCG2) reportedly associated with melanoma drug resistance in different human melanoma cells and tested the efficacy of five different anti-cancer compounds (cisplatin, doxorubicin, oridonin, paclitaxel, vemurafenib) with decreased GH action. We found that GH treatment of human melanoma cells upregulates expression of multiple ABC transporters and increases the EC50 of melanoma drug vemurafenib. Also, vemurafenib-resistant melanoma cells had upregulated levels of GH receptor (GHR) expression as well as ABC efflux pumps. GHR knockdown (KD) using siRNA in human melanoma cells treated with sub-EC50 doses of anti-tumor compounds resulted in significantly increased drug retention, decreased cell proliferation and increased drug efficacy, compared to mock-transfected controls. Our set of findings identify an unknown mechanism of GH regulation in mediating melanoma drug resistance and validates GHR as a unique therapeutic target for sensitizing highly therapy-resistant human melanoma cells to lower doses of anti-cancer drugs.

  15. Variation and evolution of the ABC transporter genes ABCB1, ABCC1, ABCG2, ABCG5 and ABCG8: implication for pharmacogenetics and disease.

    Science.gov (United States)

    Silverton, Latoya; Dean, Michael; Moitra, Karobi

    2011-01-01

    The ATP-binding cassette (ABC) transporter genes are ubiquitous in the genomes of all vertebrates. Some of these transporters play a key role in xenobiotic defense and are endowed with the capacity to efflux harmful toxic substances. A major role in the evolution of the vertebrate ABC genes is played by gene duplication. Multiple gene duplication and deletion events have been identified in ABC genes, resulting in either gene birth or gene death indicating that the process of gene evolution is still ongoing in this group of transporters. Additionally, polymorphisms in these genes are linked to variations in expression, function, drug disposition and drug response. Single nucleotide polymorphisms in the ABC genes may be considered as markers of individual risk for adverse drug reactions or susceptibility to complex diseases as they can uniquely influence the quality and quantity of gene product. As the ABC genes continue to evolve, globalization will yield additional migration and racial admixtures that will have far reaching implications for the pharmacogenetics of this unique family of transporters in the context of human health.

  16. Inhibition or knockdown of ABC transporters enhances susceptibility of adult and juvenile schistosomes to Praziquantel.

    Directory of Open Access Journals (Sweden)

    Ravi S Kasinathan

    2014-10-01

    Full Text Available Parasitic flatworms of the genus Schistosoma cause schistosomiasis, a neglected tropical disease that affects hundreds of millions. Treatment of schistosomiasis depends almost entirely on the drug praziquantel (PZQ. Though essential to treating and controlling schistosomiasis, a major limitation of PZQ is that it is not active against immature mammalian-stage schistosomes. Furthermore, there are reports of field isolates with heritable reductions in PZQ susceptibility, and researchers have selected for PZQ-resistant schistosomes in the laboratory. P-glycoprotein (Pgp; ABCB1 and other ATP binding cassette (ABC transporters remove a wide variety of toxins and xenobiotics from cells, and have been implicated in multidrug resistance (MDR. Changes in ABC transporter structure or expression levels are also associated with reduced drug susceptibility in parasitic helminths, including schistosomes. Here, we show that the activity of PZQ against schistosome adults and juveniles ex vivo is potentiated by co-administration of either the highly potent Pgp inhibitor tariquidar or combinations of inhibitors targeting multiple ABC multidrug transporters. Adult worms exposed to sublethal PZQ concentrations remain active, but co-administration of ABC transporter inhibitors results in complete loss of motility and disruption of the tegument. Notably, juvenile schistosomes (3-4 weeks post infection, normally refractory to 2 µM PZQ, become paralyzed when transporter inhibitors are added in combination with the PZQ. Experiments using the fluorescent PZQ derivative (R-PZQ-BODIPY are consistent with the transporter inhibitors increasing effective intraworm concentrations of PZQ. Adult worms in which expression of ABC transporters has been suppressed by RNA interference show increased responsiveness to PZQ and increased retention of (R-PZQ-BODIPY consistent with an important role for these proteins in setting levels of PZQ susceptibility. These results indicate that

  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. The ABC transporter ABCG29 is involved in H2O2 tolerance and biocontrol traits in the fungus Clonostachys rosea.

    Science.gov (United States)

    Dubey, Mukesh; Jensen, Dan Funck; Karlsson, Magnus

    2016-04-01

    For successful biocontrol interactions, biological control organisms must tolerate toxic metabolites produced by themselves or plant pathogens during mycoparasitic/antagonistic interactions, by host plant during colonization of the plant, and xenobiotics present in the environment. ATP-binding cassette (ABC) transporters can play a significant role in tolerance of toxic compounds by mediating active transport across the cellular membrane. This paper reports on functional characterization of an ABC transporter ABCG29 in the biocontrol fungus Clonostachys rosea strain IK726. Gene expression analysis showed induced expression of abcG29 during exposure to the Fusarium spp. mycotoxin zearalenone (ZEA) and the fungicides Cantus, Chipco Green and Apron. Expression of abcG29 in C. rosea was significantly higher during C. rosea-C. rosea (Cr-Cr) interaction or in exposure to C. rosea culture filtrate for 2 h, compared to interaction with Fusarium graminearum or 2 h exposure to F. graminearum culture filtrate. In contrast with gene expression data, ΔabcG29 strains did not display reduced tolerance towards ZEA, fungicides or chemical agents known for inducing oxidative, cell wall or osmotic stress, compared to C. rosea WT. The exception was a significant reduction in tolerance to H2O2 (10 mM) in ΔabcG29 strains when conidia were used as an inoculum. The antagonistic ability of ΔabcG29 strains towards F. graminearum, Fusarium oxysporum or Botrytis cinerea in dual plate assays were not different compared with WT. However, in biocontrol assays ΔabcG29 strains displayed reduced ability to protect Arabidopsis thaliana leaves from B. cinerea, and barley seedling from F. graminearum as measured by an A. thaliana detached leaf assay and a barley foot rot disease assay, respectively. These data show that the ABCG29 is dispensable for ZEA and fungicides tolerance, and antagonism but not H2O2 tolerance and biocontrol effects in C. rosea.

  19. The role of ABC proteins Aus1p and Pdr11p in the uptake of external sterols in yeast: dehydroergosterol fluorescence study

    DEFF Research Database (Denmark)

    Kohut, Peter; Wüstner, Daniel; Hronska, L;

    2011-01-01

    applied the fluorescent ergosterol analog dehydroergosterol (DHE) to monitor the initial steps of sterol uptake by three independent approaches: fluorescence spectroscopy, fluorescence microscopy and sterol quantification by HPLC. Using specific fluorescence characteristics of DHE we showed that the entry...... of sterol molecules into plasma membrane is not spontaneous but requires assistance of two ABC (ATP-binding cassette) pumps--Aus1p or Pdr11p. DHE taken up by uptake-competent hem1ΔAUS1PDR11 cells could be directly visualized by UV-sensitive wide field fluorescence microscopy. HPLC analysis of sterols...... revealed significant amounts of exogenous ergosterol and DHE (but not cholesterol) associated with uptake-deficient hem1Δaus1Δpdr11Δ cells. Fluorescent sterol associated with these cells did not show the characteristic emission spectrum of membrane-integrated DHE. The amount of cell-associated DHE...

  20. 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.

  1. H-loop histidine catalyzes ATP hydrolysis in the E. coli ABC-transporter HlyB.

    Science.gov (United States)

    Zhou, Yan; Ojeda-May, Pedro; Pu, Jingzhi

    2013-10-14

    Adenosine triphosphate (ATP)-binding cassette (ABC) transporters form a family of molecular motor proteins that couple ATP hydrolysis to substrate translocation across cell membranes. Each nucleotide binding domain of ABC-transporters contains a highly conserved H-loop histidine residue, whose precise mechanistic role in motor functions has remained elusive. By using combined quantum mechanical and molecular mechanical (QM/MM) calculations, we showed that the conserved H-loop residue H662 in E. coli HlyB, a bacterial ABC-transporter, can act first as a general acid and then as a general base to facilitate proton transfer in ATP hydrolysis. Without the assistance of H662, direct proton transfer from the lytic water to ATP results in a substantially higher barrier height. Our findings suggest that the essential function of the H-loop residue H662 is to provide a "chemical linchpin" that shuttles protons between reactants through a relay mechanism, thereby catalyzing ATP hydrolysis in HlyB.

  2. Key Role of Human ABC Transporter ABCG2 in Photodynamic Therapy and Photodynamic Diagnosis

    Directory of Open Access Journals (Sweden)

    Toshihisa Ishikawa

    2010-01-01

    Full Text Available Accumulating evidence indicates that ATP-binding cassette (ABC transporter ABCG2 plays a key role in regulating the cellular accumulation of porphyrin derivatives in cancer cells and thereby affects the efficacy of photodynamic therapy and photodynamic diagnosis. The activity of porphyrin efflux can be affected by genetic polymorphisms in the ABCG2 gene. On the other hand, Nrf2, an NF-E2-related transcription factor, has been shown to be involved in oxidative stress-mediated induction of the ABCG2 gene. Since patients have demonstrated individual differences in their response to photodynamic therapy, transcriptional activation and/or genetic polymorphisms of the ABCG2 gene in cancer cells may affect patients' responses to photodynamic therapy. Protein kinase inhibitors, including imatinib mesylate and gefitinib, are suggested to potentially enhance the efficacy of photodynamic therapy by blocking ABCG2-mediated porphyrin efflux from cancer cells. This review article provides an overview on the role of human ABC transporter ABCG2 in photodynamic therapy and photodynamic diagnosis.

  3. Structure, biosynthesis, and function of bacterial capsular polysaccharides synthesized by ABC transporter-dependent pathways.

    Science.gov (United States)

    Willis, Lisa M; Whitfield, Chris

    2013-08-30

    Bacterial capsules are formed primarily from long-chain polysaccharides with repeat-unit structures. A given bacterial species can produce a range of capsular polysaccharides (CPSs) with different structures and these help distinguish isolates by serotyping, as is the case with Escherichia coli K antigens. Capsules are important virulence factors for many pathogens and this review focuses on CPSs synthesized via ATP-binding cassette (ABC) transporter-dependent processes in Gram-negative bacteria. Bacteria utilizing this pathway are often associated with urinary tract infections, septicemia, and meningitis, and E. coli and Neisseria meningitidis provide well-studied examples. CPSs from ABC transporter-dependent pathways are synthesized at the cytoplasmic face of the inner membrane through the concerted action of glycosyltransferases before being exported across the inner membrane and translocated to the cell surface. A hallmark of these CPSs is a conserved reducing terminal glycolipid composed of phosphatidylglycerol and a poly-3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) linker. Recent discovery of the structure of this conserved lipid terminus provides new insights into the early steps in CPS biosynthesis.

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

    Directory of Open Access Journals (Sweden)

    Saroj Velamakanni

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

  5. Molecular mechanism of ATP binding and ion channel activation in P2X receptors

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, Motoyuki; Gouaux, Eric (Oregon HSU)

    2012-10-24

    P2X receptors are trimeric ATP-activated ion channels permeable to Na{sup +}, K{sup +} and Ca{sup 2+}. The seven P2X receptor subtypes are implicated in physiological processes that include modulation of synaptic transmission, contraction of smooth muscle, secretion of chemical transmitters and regulation of immune responses. Despite the importance of P2X receptors in cellular physiology, the three-dimensional composition of the ATP-binding site, the structural mechanism of ATP-dependent ion channel gating and the architecture of the open ion channel pore are unknown. Here we report the crystal structure of the zebrafish P2X4 receptor in complex with ATP and a new structure of the apo receptor. The agonist-bound structure reveals a previously unseen ATP-binding motif and an open ion channel pore. ATP binding induces cleft closure of the nucleotide-binding pocket, flexing of the lower body {beta}-sheet and a radial expansion of the extracellular vestibule. The structural widening of the extracellular vestibule is directly coupled to the opening of the ion channel pore by way of an iris-like expansion of the transmembrane helices. The structural delineation of the ATP-binding site and the ion channel pore, together with the conformational changes associated with ion channel gating, will stimulate development of new pharmacological agents.

  6. Linoleic acid suppresses cholesterol efflux and ATP-binding cassette transporters in murine bone marrow-derived macrophages

    Science.gov (United States)

    Individuals with type 2 diabetes mellitus (T2DM) are at increased risk of developing cardiovascular disease (CVD), possibly associated with elevated plasma free fatty acid concentrations. Paradoxically, evidence suggests that unsaturated, compared to saturated fatty acids, suppress macrophage chole...

  7. Function and regulation of ATP-binding cassette transport proteins involved in hepatobiliary transport (vol 12, pg 13, 2000)

    NARCIS (Netherlands)

    Hooiveld, GJEJ; van Montfoort, JE; Meijer, DKF; Muller, M

    2001-01-01

    Hepatobiliary transport of endogenous and exogenous compounds is mediated by the coordinated action of multiple transport systems present at the sinusoidal (basolateral) and canalicular (apical) membrane domains of hepatocytes. During the last few years many of these transporters have been cloned an

  8. Conformational plasticity of the type I maltose ABC importer.

    Science.gov (United States)

    Böhm, Simon; Licht, Anke; Wuttge, Steven; Schneider, Erwin; Bordignon, Enrica

    2013-04-01

    ATP-binding cassette (ABC) transporters couple the translocation of solutes across membranes to ATP hydrolysis. Crystal structures of the Escherichia coli maltose importer (MalFGK2) in complex with its substrate binding protein (MalE) provided unprecedented insights in the mechanism of substrate translocation, leaving the MalE-transporter interactions still poorly understood. Using pulsed EPR and cross-linking methods we investigated the effects of maltose and MalE on complex formation and correlated motions of the MalK2 nucleotide-binding domains (NBDs). We found that both substrate-free (open) and liganded (closed) MalE interact with the transporter with similar affinity in all nucleotide states. In the apo-state, binding of open MalE occurs via the N-lobe, leaving the C-lobe disordered, but upon maltose binding, closed MalE associates tighter to the transporter. In both cases the NBDs remain open. In the presence of ATP, the transporter binds both substrate-free and liganded MalE, both inducing the outward-facing conformation trapped in the crystal with open MalE at the periplasmic side and NBDs tightly closed. In contrast to ATP, ADP-Mg(2+) alone is sufficient to induce a semiopen conformation in the NBDs. In this nucleotide-driven state, the transporter binds both open and closed MalE with slightly different periplasmic configurations. We also found that dissociation of MalE is not a required step for substrate translocation since a supercomplex with MalE cross-linked to MalG retains the ability to hydrolyze ATP and to transport maltose. These features of MalE-MalFGK2 interactions highlight the conformational plasticity of the maltose importer, providing insights into the ATPase stimulation by unliganded MalE.

  9. Hamiltonian ABC

    NARCIS (Netherlands)

    Meeds, E.; Leenders, R.; Welling, M.; Meila, M.; Heskes, T.

    2015-01-01

    Approximate Bayesian computation (ABC) is a powerful and elegant framework for performing inference in simulation-based models. However, due to the difficulty in scaling likelihood estimates, ABC remains useful for relatively lowdimensional problems. We introduce Hamiltonian ABC (HABC), a set of lik

  10. Inter-domain communication mechanisms in an ABC importer: a molecular dynamics study of the MalFGK2E complex.

    Science.gov (United States)

    Oliveira, A Sofia F; Baptista, António M; Soares, Cláudio M

    2011-08-01

    ATP-Binding Cassette transporters are ubiquitous membrane proteins that convert the energy from ATP-binding and hydrolysis into conformational changes of the transmembrane region to allow the translocation of substrates against their concentration gradient. Despite the large amount of structural and biochemical data available for this family, it is still not clear how the energy obtained from ATP hydrolysis in the ATPase domains is "transmitted" to the transmembrane domains. In this work, we focus our attention on the consequences of hydrolysis and inorganic phosphate exit in the maltose uptake system (MalFGK(2)E) from Escherichia coli. The prime goal is to identify and map the structural changes occurring during an ATP-hydrolytic cycle. For that, we use extensive molecular dynamics simulations to study three potential intermediate states (with 10 replicates each): an ATP-bound, an ADP plus inorganic phosphate-bound and an ADP-bound state. Our results show that the residues presenting major rearrangements are located in the A-loop, in the helical sub-domain, and in the "EAA motif" (especially in the "coupling helices" region). Additionally, in one of the simulations with ADP we were able to observe the opening of the NBD dimer accompanied by the dissociation of ADP from the ABC signature motif, but not from its corresponding P-loop motif. This work, together with several other MD studies, suggests a common communication mechanism both for importers and exporters, in which ATP-hydrolysis induces conformational changes in the helical sub-domain region, in turn transferred to the transmembrane domains via the "coupling helices".

  11. Inter-domain communication mechanisms in an ABC importer: a molecular dynamics study of the MalFGK2E complex.

    Directory of Open Access Journals (Sweden)

    A Sofia F Oliveira

    2011-08-01

    Full Text Available ATP-Binding Cassette transporters are ubiquitous membrane proteins that convert the energy from ATP-binding and hydrolysis into conformational changes of the transmembrane region to allow the translocation of substrates against their concentration gradient. Despite the large amount of structural and biochemical data available for this family, it is still not clear how the energy obtained from ATP hydrolysis in the ATPase domains is "transmitted" to the transmembrane domains. In this work, we focus our attention on the consequences of hydrolysis and inorganic phosphate exit in the maltose uptake system (MalFGK(2E from Escherichia coli. The prime goal is to identify and map the structural changes occurring during an ATP-hydrolytic cycle. For that, we use extensive molecular dynamics simulations to study three potential intermediate states (with 10 replicates each: an ATP-bound, an ADP plus inorganic phosphate-bound and an ADP-bound state. Our results show that the residues presenting major rearrangements are located in the A-loop, in the helical sub-domain, and in the "EAA motif" (especially in the "coupling helices" region. Additionally, in one of the simulations with ADP we were able to observe the opening of the NBD dimer accompanied by the dissociation of ADP from the ABC signature motif, but not from its corresponding P-loop motif. This work, together with several other MD studies, suggests a common communication mechanism both for importers and exporters, in which ATP-hydrolysis induces conformational changes in the helical sub-domain region, in turn transferred to the transmembrane domains via the "coupling helices".

  12. Functional genetic identification of PRP1, an ABC transporter superfamily member conferring pentamidine resistance in Leishmania major.

    Science.gov (United States)

    Coelho, Adriano C; Beverley, Stephen M; Cotrim, Paulo C

    2003-08-31

    Pentamidine (PEN) is a second-line agent in the treatment of leishmaniasis whose mode of action and resistance is not well understood. Here, we used a genetic strategy to search for loci able to mediate PEN resistance (PENr) when overexpressed in Leishmania major. A shuttle cosmid library containing genomic DNA inserts was transfected into wild-type promastigotes and screened for PEN-resistant transfectants. Two different cosmids identifying the same locus were found, which differed from other known Leishmania drug resistance genes. The PENr gene was mapped by deletion and transposon mutagenesis to an open reading frame (ORF) belonging to the P-glycoprotein (PGP)/MRP ATP-binding cassette (ABC) transporter superfamily that we named pentamidine resistance protein 1 (PRP1). The predicted PRP1 protein encodes 1,807 amino acids with the typical dimeric structure involving 10 transmembrane domains and two nucleotide-binding domains (NBDs). PRP1-mediated PENr could be reversed by verapamil and PRP1 overexpressors showed cross-resistance to trivalent antimony but not to pentavalent antimony (glucantime). Although the degree of PENr was modest (1.7- to 3.7-fold), this may be significant in clinical drug resistance given the marginal efficacy of PEN against Leishmania.

  13. ATP-Binding Cassettee Transporter Signals Salt-Induced Stomatal Closure in Arabidopsis thaliana L. by H2S Pathway%ABC转运体位于H2S上游参与盐胁迫诱导的拟南芥气孔关闭

    Institute of Scientific and Technical Information of China (English)

    吴延朋; 李洪旺; 侯丽霞; 张丹丹; 刘新

    2014-01-01

    本文以拟南芥野生型、ABC转运体缺失突变体(Atmrp4、Atmrp5和Atmrp4/5)为材料研究了硫化氢(hydrogen sulfide, H2S)和ABC转运体在盐胁迫诱导拟南芥气孔关闭中的作用及其相互关系。结果表明,盐胁迫能够引起拟南芥叶片AtMRP4及AtMRP5表达量显著升高,诱导野生型拟南芥叶片气孔关闭,但对Atmrp4、Atmrp5及Atmrp4/5气孔开度无显著影响;而ABC转运体抑制剂格列本脲(glibenclamide, Gli)可减弱盐胁迫诱导的拟南芥气孔关闭的作用,表明ABC转运体参与盐胁迫诱导的拟南芥气孔关闭过程。盐胁迫能够引起野生型拟南芥H2S合成相关酶L-/D-半胱氨酸脱巯基酶(L-/D-CDes)活性及H2S含量显著升高,而ABC转运体抑制剂格列本脲处理后则没有这种变化,同时盐胁迫也不能引起Atmrp4、Atmrp5及Atmrp4/5的L-/D-CDes活性及H2S含量显著升高,表明ABC转运体位于H2S上游参与盐胁迫诱导气孔关闭过程。%Using Arabidopsis thaliana wild type, ATP-binding cassette (ABC) transporter deficient mutants Atmrp4, Atmrp5, Atmrp4/5 as materials, the participation of hydrogen sulifde (H2S) and ABC transporter signal pathway in salt-induced stomatal closure were studied. These results showed that AtMRP4 and AtMRP5 transcription rate in Arabidopsis leaves increased dramaticly under salt stress, and salt stress induced stomata closure in wild type, but had no effect on Atmrp4, Atmrp5 and Atmrp4/5. The ABC transporter inhibitor glibenclamide (Gli) inhibited the inducing effects of salt stress on stomata closure in wild type, it could be deduced that ABC transporter participate in salt-induced stomatal closure in Arabidopsis. Salt-induced increase in L-/D-cysteine desulfhydrase (L-/D-CDes, enzymes participate in H2S production) activities and H2S content could be seen in wild type, but had no effect on wild type treated by Gli as well as Atmrp4, Atmrp5, Atmrp4/5. All these results indicated that ABC transporter functions upstream

  14. ATP binding and aspartate protonation enhance photoinduced electron transfer in plant cryptochrome.

    Science.gov (United States)

    Cailliez, Fabien; Müller, Pavel; Gallois, Michaël; de la Lande, Aurélien

    2014-09-17

    Cryptochromes are flavoproteins encountered in most vegetal and animal species. They play a role of blue-light receptors in plants and in invertebrates. The putative resting state of the FAD cofactor in these proteins is its fully oxidized form, FADox. Upon blue-light excitation, the isoalloxazine ring (ISO) may undergo an ultrafast reduction by a nearby tryptophan residue W400. This primary reduction triggers a cascade of electron and proton transfers, ultimately leading to the formation of the FADH° radical. A recent experimental study has shown that the yield of FADH° formation in Arabidopsis cryptochrome can be strongly modulated by ATP binding and by pH, affecting the protonation state of D396 (proton donor to FAD°(-)). Here we provide a detailed molecular analysis of these effects by means of combined classical molecular dynamics simulations and time-dependent density functional theory calculations. When ATP is present and D396 protonated, FAD remains in close contact with W400, thereby enhancing electron transfer (ET) from W400 to ISO*. In contrast, deprotonation of D396 and absence of ATP introduce flexibility to the photoactive site prior to FAD excitation, with the consequence of increased ISO-W400 distance and diminished tunneling rate by almost two orders of magnitude. We show that under these conditions, ET from the adenine moiety of FAD becomes a competitive relaxation pathway. Overall, our data suggest that the observed effects of ATP and pH on the FAD photoreduction find their roots in the earliest stage of the photoreduction process; i.e., ATP binding and the protonation state of D396 determine the preferred pathway of ISO* relaxation.

  15. NCBI nr-aa BLAST: CBRC-TTRU-01-0272 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-0272 ref|ZP_03055167.1| cyclodextrin ABC superfamily ATP binding casse...tte transporter, membrane protein [Bacillus pumilus ATCC 7061] gb|EDW21594.1| cyclodextrin ABC superfamily A

  16. 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

  17. Enterococcus faecalis uses a PTS 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

    2017-02-27

    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 Pi 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 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, major health-care associated pathogens, are difficult to treat due to their increasing resistance to clinically relevant antibiotics and new

  18. 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

  19. 巴西橡胶树胶乳表达ABC转运蛋白HbGCN1的克隆与表达研究%loning and Expression Analysis of HbGCN1 Encoding an ABC Transporter in the Latex of Rubber Tree (Hevea brasiliensis Müll.Arg.)

    Institute of Scientific and Technical Information of China (English)

    聂智毅; 黎瑜; 李波; 夏可灿; 段翠芳

    2012-01-01

    橡胶生物合成是一种典型的植物类异戊二烯次生代谢,它是影响橡胶产量的首要因素.ABC转运蛋白(ATP Binding Cassette transporter,ABC transporter)是一类与植物次生代谢密切相关的蛋白大家族.筛选已构建的茉莉酸诱导橡胶树胶乳消减文库,并克隆了1个GCN(general control non-repressible)亚族ABC转运蛋白基因EST,通过RACE技术获得其全长cDNA序列,命名为HbGCN1.该基因开放阅读框共1 815 bp,编码605个氨基酸残基.表达分析表明:HbGCN1主要在橡胶树树皮及胶乳中表达,且在乙烯、茉莉酸或伤害诱导下上调表达,推测其可能与橡胶生物合成相关.原核表达该基因,为进一步的研究奠定基础.%Rubber biosynthesis, a typical isoprenoid biosynthesis pathway, has been the key important factor limiting rubber latex yield. ABC (ATP-BindingCassette)transporters are a large protein family which is closely involved in the plant secondary metabolites. Through screening a jasmonic -induced latex SSH cDNA library combined with RACE, one EST encoding ABC transporter of GCN subgroup and its full-length cDNA, named as HbGCNl were obtained. HbGCNl contains a ORF with 1 815 bp and encodes a polypeptide of 605 amino acids. The expression patterns show that HbGCNl is primarily expressed in latex or bark. Under ethylene, jasmonic acid and wounding induction, its expression is up-regulated. Based on the above analysis, it is speculated that HbGCNl may be closely correlated to the rubber biosynthesis. Moreover, the prokaryotie expression of the gene lay the foundation for further research.

  20. Genetic variation in the proximal promoter of ABC and SLC superfamilies: liver and kidney specific expression and promoter activity predict variation.

    Directory of Open Access Journals (Sweden)

    Stephanie E Hesselson

    Full Text Available Membrane transporters play crucial roles in the cellular uptake and efflux of an array of small molecules including nutrients, environmental toxins, and many clinically used drugs. We hypothesized that common genetic variation in the proximal promoter regions of transporter genes contribute to observed variation in drug response. A total of 579 polymorphisms were identified in the proximal promoters (-250 to +50 bp and flanking 5' sequence of 107 transporters in the ATP Binding Cassette (ABC and Solute Carrier (SLC superfamilies in 272 DNA samples from ethnically diverse populations. Many transporter promoters contained multiple common polymorphisms. Using a sliding window analysis, we observed that, on average, nucleotide diversity (pi was lowest at approximately 300 bp upstream of the transcription start site, suggesting that this region may harbor important functional elements. The proximal promoters of transporters that were highly expressed in the liver had greater nucleotide diversity than those that were highly expressed in the kidney consistent with greater negative selective pressure on the promoters of kidney transporters. Twenty-one promoters were evaluated for activity using reporter assays. Greater nucleotide diversity was observed in promoters with strong activity compared to promoters with weak activity, suggesting that weak promoters are under more negative selective pressure than promoters with high activity. Collectively, these results suggest that the proximal promoter region of membrane transporters is rich in variation and that variants in these regions may play a role in interindividual variation in drug disposition and response.

  1. The Half-Size ABC Transporter FOLDED PETALS 2/ABCG13 Is Involved in Petal Elongation through Narrow Spaces in Arabidopsis thaliana Floral Buds

    Directory of Open Access Journals (Sweden)

    Seiji Takeda

    2014-08-01

    Full Text Available Flowers are vital for attracting pollinators to plants and in horticulture for humans. Petal morphogenesis is a central process of floral development. Petal development can be divided into three main processes: the establishment of organ identity in a concentric pattern, primordia initiation at fixed positions within a whorl, and morphogenesis, which includes petal elongation through the narrow spaces within the bud. Here, we show that the FOLDED PETALS 2 (FOP2 gene, encoding a member of the half-size ATP binding cassette (ABC transporter family ABCG13, is involved in straight elongation of petals in Arabidopsis thaliana. In fop2 mutants, flowers open with folded petals, instead of straight-elongated ones found in the wild type. The epicuticular nanoridge structures are absent in many abaxial epidermal cells of fop2 petals, and surgical or genetic generation of space in young fop2 buds restores the straight elongation of petals, suggesting that the physical contact of sepals and petals causes the petal folding. Similar petal folding has been reported in the fop1 mutant, and the petals of fop2 fop1 double mutants resemble those of both the fop1 and fop2 single mutants, although the epidermal structure and permeability of the petal surface is more affected in fop2. Our results suggest that synthesis and transport of cutin or wax in growing petals play an important role for their smooth elongation through the narrow spaces of floral buds.

  2. A rice ABC transporter, OsABCC1, reduces arsenic accumulation in the grain

    Science.gov (United States)

    Song, Won-Yong; Yamaki, Tomohiro; Yamaji, Naoki; Ko, Donghwi; Jung, Ki-Hong; Fujii-Kashino, Miho; An, Gynheung; Martinoia, Enrico; Lee, Youngsook; Ma, Jian Feng

    2014-01-01

    Arsenic (As) is a chronic poison that causes severe skin lesions and cancer. Rice (Oryza sativa L.) is a major dietary source of As; therefore, reducing As accumulation in the rice grain and thereby diminishing the amount of As that enters the food chain is of critical importance. Here, we report that a member of the Oryza sativa C-type ATP-binding cassette (ABC) transporter (OsABCC) family, OsABCC1, is involved in the detoxification and reduction of As in rice grains. We found that OsABCC1 was expressed in many organs, including the roots, leaves, nodes, peduncle, and rachis. Expression was not affected when plants were exposed to low levels of As but was up-regulated in response to high levels of As. In both the basal nodes and upper nodes, which are connected to the panicle, OsABCC1 was localized to the phloem region of vascular bundles. Furthermore, OsABCC1 was localized to the tonoplast and conferred phytochelatin-dependent As resistance in yeast. Knockout of OsABCC1 in rice resulted in decreased tolerance to As, but did not affect cadmium toxicity. At the reproductive growth stage, the As content was higher in the nodes and in other tissues of wild-type rice than in those of OsABCC1 knockout mutants, but was significantly lower in the grain. Taken together, our results indicate that OsABCC1 limits As transport to the grains by sequestering As in the vacuoles of the phloem companion cells of the nodes in rice. PMID:25331872

  3. Data for proteomic analysis of ATP-binding proteins and kinase inhibitor target proteins using an ATP probe

    Directory of Open Access Journals (Sweden)

    Jun Adachi

    2015-12-01

    Full Text Available Interactions between ATP and ATP-binding proteins (ATPome are common and are required for most cellular processes. Thus, it is clearly important to identify and quantify these interactions for understanding basic cellular mechanisms and the pathogenesis of various diseases. We used an ATP competition assay (competition between ATP and acyl-ATP probes that enabled us to distinguish specific ATP-binding proteins from non-specific proteins (Adachi et al., 2014 [1]. As a result, we identified 539 proteins, including 178 novel ATP-binding protein candidates. We also established an ATPome selectivity profiling method for kinase inhibitors using our cataloged ATPome list. Normally only kinome selectivity is profiled in selectivity profiling of kinase inhibitors. In this data, we expand the profiled targets from the kinome to the ATPome through performance of ATPome selectivity profiling and obtained target profiles of staurosporine and (S-crizotinib. The data accompanying the manuscript on this approach (Adachi et al., 2014 [1] have been deposited to the ProteomeXchange with identifier PXD001200.

  4. Molecular determinants for ATP-binding in proteins: a data mining and quantum chemical analysis.

    Science.gov (United States)

    Mao, Lisong; Wang, Yanli; Liu, Yuemin; Hu, Xiche

    2004-02-20

    intermolecular interactions of large biomolecular systems becomes computationally feasible. The establishment of the molecular basis for recognition of the adenine moiety of ATP in proteins will directly impact molecular design of ATP-binding site targeted enzyme inhibitors such as kinase inhibitors.

  5. 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.

  6. 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

  7. Inhibition of the Human ABC Efflux Transporters P-gp and BCRP by the BDE-47 Hydroxylated Metabolite 6-OH-BDE-47: Considerations for Human Exposure.

    Science.gov (United States)

    Marchitti, Satori A; Mazur, Christopher S; Dillingham, Caleb M; Rawat, Swati; Sharma, Anshika; Zastre, Jason; Kenneke, John F

    2017-01-01

    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 [((3)H)-paclitaxel and ((3)H)-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. These findings suggest that some effects previously attributed to BDE-47 in biological systems may actually be due to 6-OH-BDE-47. Considerations for human exposure are discussed.

  8. Activity-Based Proteomics Reveals Heterogeneous Kinome and ATP-Binding Proteome Responses to MEK Inhibition in KRAS Mutant Lung Cancer.

    Science.gov (United States)

    Kim, Jae-Young; Stewart, Paul A; Borne, Adam L; Fang, Bin; Welsh, Eric A; Chen, Yian Ann; Eschrich, Steven A; Koomen, John M; Haura, Eric B

    2016-06-01

    One way cancer cells can escape from targeted agents is through their ability to evade drug effects by rapidly rewiring signaling networks. Many protein classes, such as kinases and metabolic enzymes, are regulated by ATP binding and hydrolysis. We hypothesized that a system-level profiling of drug-induced alterations in ATP-binding proteomes could offer novel insights into adaptive responses. Here, we mapped global ATP-binding proteomes perturbed by two clinical MEK inhibitors, AZD6244 and MEK162, in KRAS mutant lung cancer cells as a model system harnessing a desthiobiotin-ATP probe coupled with LC-MS/MS. We observed strikingly unique ATP-binding proteome responses to MEK inhibition, which revealed heterogeneous drug-induced pathway signatures in each cell line. We also identified diverse kinome responses, indicating each cell adapts to MEK inhibition in unique ways. Despite the heterogeneity of kinome responses, decreased probe labeling of mitotic kinases and an increase of kinases linked to autophagy were identified to be common responses. Taken together, our study revealed a diversity of adaptive ATP-binding proteome and kinome responses to MEK inhibition in KRAS mutant lung cancer cells, and our study further demonstrated the utility of our approach to identify potential candidates of targetable ATP-binding enzymes involved in adaptive resistance and to develop rational drug combinations.

  9. Activity-Based Proteomics Reveals Heterogeneous Kinome and ATP-Binding Proteome Responses to MEK Inhibition in KRAS Mutant Lung Cancer

    Directory of Open Access Journals (Sweden)

    Jae-Young Kim

    2016-04-01

    Full Text Available One way cancer cells can escape from targeted agents is through their ability to evade drug effects by rapidly rewiring signaling networks. Many protein classes, such as kinases and metabolic enzymes, are regulated by ATP binding and hydrolysis. We hypothesized that a system-level profiling of drug-induced alterations in ATP-binding proteomes could offer novel insights into adaptive responses. Here, we mapped global ATP-binding proteomes perturbed by two clinical MEK inhibitors, AZD6244 and MEK162, in KRAS mutant lung cancer cells as a model system harnessing a desthiobiotin-ATP probe coupled with LC-MS/MS. We observed strikingly unique ATP-binding proteome responses to MEK inhibition, which revealed heterogeneous drug-induced pathway signatures in each cell line. We also identified diverse kinome responses, indicating each cell adapts to MEK inhibition in unique ways. Despite the heterogeneity of kinome responses, decreased probe labeling of mitotic kinases and an increase of kinases linked to autophagy were identified to be common responses. Taken together, our study revealed a diversity of adaptive ATP-binding proteome and kinome responses to MEK inhibition in KRAS mutant lung cancer cells, and our study further demonstrated the utility of our approach to identify potential candidates of targetable ATP-binding enzymes involved in adaptive resistance and to develop rational drug combinations.

  10. ATP binding and hydrolysis-driven rate-determining events in the RFC-catalyzed PCNA clamp loading reaction.

    Science.gov (United States)

    Sakato, Miho; Zhou, Yayan; Hingorani, Manju M

    2012-02-17

    The multi-subunit replication factor C (RFC) complex loads circular proliferating cell nuclear antigen (PCNA) clamps onto DNA where they serve as mobile tethers for polymerases and coordinate the functions of many other DNA metabolic proteins. The clamp loading reaction is complex, involving multiple components (RFC, PCNA, DNA, and ATP) and events (minimally: PCNA opening/closing, DNA binding/release, and ATP binding/hydrolysis) that yield a topologically linked clamp·DNA product in less than a second. Here, we report pre-steady-state measurements of several steps in the reaction catalyzed by Saccharomyces cerevisiae RFC and present a comprehensive kinetic model based on global analysis of the data. Highlights of the reaction mechanism are that ATP binding to RFC initiates slow activation of the clamp loader, enabling it to open PCNA (at ~2 s(-1)) and bind primer-template DNA (ptDNA). Rapid binding of ptDNA leads to formation of the RFC·ATP·PCNA(open)·ptDNA complex, which catalyzes a burst of ATP hydrolysis. Another slow step in the reaction follows ATP hydrolysis and is associated with PCNA closure around ptDNA (8 s(-1)). Dissociation of PCNA·ptDNA from RFC leads to catalytic turnover. We propose that these early and late rate-determining events are intramolecular conformational changes in RFC and PCNA that control clamp opening and closure, and that ATP binding and hydrolysis switch RFC between conformations with high and low affinities, respectively, for open PCNA and ptDNA, and thus bookend the clamp loading reaction.

  11. Variants in the ATP-Binding Cassette Transporter (ABCA7), Apolipoprotein E ε4, and the Risk of Late-Onset Alzheimer Disease in African Americans

    Science.gov (United States)

    Reitz, Christiane; Jun, Gyungah; Naj, Adam; Rajbhandary, Ruchita; Vardarajan, Badri Narayan; Wang, Li-San; Valladares, Otto; Lin, Chiao-Feng; Larson, Eric B.; Graff-Radford, Neill R.; Evans, Denis; De Jager, Philip L.; Crane, Paul K.; Buxbaum, Joseph D.; Murrell, Jill R.; Raj, Towfique; Ertekin-Taner, Nilufer; Logue, Mark; Baldwin, Clinton T.; Green, Robert C.; Barnes, Lisa L.; Cantwell, Laura B.; Fallin, M. Daniele; Go, Rodney C. P.; Griffith, Patrick; Obisesan, Thomas O.; Manly, Jennifer J.; Lunetta, Kathryn L.; Kamboh, M. Ilyas; Lopez, Oscar L.; Bennett, David A.; Hendrie, Hugh; Hall, Kathleen S.; Goate, Alison M.; Byrd, Goldie S.; Kukull, Walter A.; Foroud, Tatiana M.; Haines, Jonathan L.; Farrer, Lindsay A.; Pericak-Vance, Margaret A.; Schellenberg, Gerard D.; Mayeux, Richard

    2013-01-01

    Importance Genetic variants associated with susceptibility to late-onset Alzheimer disease are known for individuals of European ancestry, but whether the same or different variants account for the genetic risk of Alzheimer disease in African American individuals is unknown. Identification of disease-associated variants helps identify targets for genetic testing, prevention, and treatment. Objective To identify genetic loci associated with late-onset Alzheimer disease in African Americans. Design, Setting, and Participants The Alzheimer Disease Genetics Consortium (ADGC) assembled multiple data sets representing a total of 5896 African Americans (1968 case participants, 3928 control participants) 60 years or older that were collected between 1989 and 2011 at multiple sites. The association of Alzheimer disease with genotyped and imputed single-nucleotide polymorphisms (SNPs) was assessed in case-control and in family-based data sets. Results from individual data sets were combined to perform an inverse variance–weighted meta-analysis, first with genome-wide analyses and subsequently with gene-based tests for previously reported loci. Main Outcomes and Measures Presence of Alzheimer disease according to standardized criteria. Results Genome-wide significance in fully adjusted models (sex, age, APOE genotype, population stratification) was observed for a SNP in ABCA7 (rs115550680, allele = G; frequency, 0.09 cases and 0.06 controls; odds ratio [OR], 1.79 [95% CI, 1.47-2.12]; P = 2.2 × 10–9), which is in linkage disequilibrium with SNPs previously associated with Alzheimer disease in Europeans (0.8

  12. AtMRP1 gene of Arabidopsis encodes a glutathione S-conjugate pump: Isolation and functional definition of a plant ATP-binding cassette transporter gene

    OpenAIRE

    Lu, Yu-Ping; Li, Ze-Sheng; Rea, Philip A.

    1997-01-01

    Because plants produce cytotoxic compounds to which they, themselves, are susceptible and are exposed to exogenous toxins (microbial products, allelochemicals, and agrochemicals), cell survival is contingent on mechanisms for detoxifying these agents. One detoxification mechanism is the glutathione S-transferase-catalyzed glutathionation of the toxin, or an activated derivative, and transport of the conjugate out of the cytosol. We show here that a transporter responsible for the removal of g...

  13. ABC转运蛋白提升四膜虫对DDT的耐受能力%ATP-binding cassette transporter enhances Tetrahymena tolerance to DDT

    Institute of Scientific and Technical Information of China (English)

    宁应之; 党怀; 刘光龙; 熊杰; 袁冬霞; 冯立芳; 缪炜

    2014-01-01

    世界卫生组织允许DDT在部分国家和地区使用.大规模频繁使用杀虫剂造成了蚊子的抗药性,大大降低了DDT的防治效果.目前对于DDT的耐受主要集中在蚊子,但对于喷洒的DDT进入水生态系统后,造成食物链底层水生生物体对DDT耐受还未见报道.本研究对DDT胁迫下的四膜虫全基因组中筛选出一个ATP结合盒转运蛋白基因(abcb15),它能够识别DDT作为其转运的底物.绿色荧光蛋白标记显示ABCB 15蛋白定位于细胞膜上,是一个细胞膜泵蛋白.基因敲降技术造成的abcb15基因敲降株在DDT胁迫下表现出更低的生长速率,这表明ABCB15膜泵蛋白能够将进入细胞内的DDT转运至细胞膜外,藉以提高四膜虫对DDT的耐受能力,以减轻DDT对细胞的损伤.

  14. Genetic association analysis of ATP binding cassette protein family reveals a novel association of ABCB1 genetic variants with epilepsy risk, but not with drug-resistance.

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    Shabeesh Balan

    Full Text Available Epilepsy constitutes a heterogeneous group of disorders that is characterized by recurrent unprovoked seizures due to widely different etiologies. Multidrug resistance remains a major issue in clinical epileptology, where one third of patients with epilepsy continue to have seizures. Role of efflux transporters in multidrug resistant epilepsy has been attributed to drug-resistant epilepsy although, with discrepant observation in genetic studies. These discrepancies could be attributed to variety of factors such as variable definition of the anti-epileptic drug (AED-resistance, variable epilepsy phenotypes and ethnicities among the studies. In the present study we inquired the role of multidrug transporters ABCB1 and ABCG2 variants in determining AED-resistance and susceptibility to epilepsy in three well-characterized cohorts comprising of mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS (prototype for AED-resistant epilepsy; juvenile myoclonic epilepsy (JME (prototype for AED-responsive epilepsy; and healthy non-epileptic controls, in 738 subjects of Malayalam speaking south Indian ancestry. ABCB1 and ABCG2 variants were not found to be associated with drug resistance when AED-resistant and AED-responsive cohorts were compared. However, a significant association was observed between ABCB1 (C3435T rs1045642 and risk of having epilepsy (MTLE-HS and JME pooled cohort; genotypic p-value = 0.0002; allelic p-value = 0.004. This association was seen persistent with MTLE-HS (genotypic p-value = 0.0008; allelic p-value = 0.004 and also with JME (genotypic p-value = 0.01; allelic p-value = 0.05 cohort individually. In-silico functional prediction indicated that ABCB1 rs1045642 has a deleterious impact on protein coding function and in splicing regulation. We conclude that the ABCB1 and ABCG2 variants do not confer to AED-resistance in the study population. However, ABCB1 rs1045642 increases vulnerability to epilepsy with greater tendency for MTLE-HS in south Indian ancestry from Kerala.

  15. Genetic association analysis of ATP binding cassette protein family reveals a novel association of ABCB1 genetic variants with epilepsy risk, but not with drug-resistance.

    Science.gov (United States)

    Balan, Shabeesh; Bharathan, Sumitha Prameela; Vellichiramal, Neetha Nanoth; Sathyan, Sanish; Joseph, Vijai; Radhakrishnan, Kurupath; Banerjee, Moinak

    2014-01-01

    Epilepsy constitutes a heterogeneous group of disorders that is characterized by recurrent unprovoked seizures due to widely different etiologies. Multidrug resistance remains a major issue in clinical epileptology, where one third of patients with epilepsy continue to have seizures. Role of efflux transporters in multidrug resistant epilepsy has been attributed to drug-resistant epilepsy although, with discrepant observation in genetic studies. These discrepancies could be attributed to variety of factors such as variable definition of the anti-epileptic drug (AED)-resistance, variable epilepsy phenotypes and ethnicities among the studies. In the present study we inquired the role of multidrug transporters ABCB1 and ABCG2 variants in determining AED-resistance and susceptibility to epilepsy in three well-characterized cohorts comprising of mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) (prototype for AED-resistant epilepsy); juvenile myoclonic epilepsy (JME) (prototype for AED-responsive epilepsy); and healthy non-epileptic controls, in 738 subjects of Malayalam speaking south Indian ancestry. ABCB1 and ABCG2 variants were not found to be associated with drug resistance when AED-resistant and AED-responsive cohorts were compared. However, a significant association was observed between ABCB1 (C3435T) rs1045642 and risk of having epilepsy (MTLE-HS and JME pooled cohort; genotypic p-value = 0.0002; allelic p-value = 0.004). This association was seen persistent with MTLE-HS (genotypic p-value = 0.0008; allelic p-value = 0.004) and also with JME (genotypic p-value = 0.01; allelic p-value = 0.05) cohort individually. In-silico functional prediction indicated that ABCB1 rs1045642 has a deleterious impact on protein coding function and in splicing regulation. We conclude that the ABCB1 and ABCG2 variants do not confer to AED-resistance in the study population. However, ABCB1 rs1045642 increases vulnerability to epilepsy with greater tendency for MTLE-HS in south Indian ancestry from Kerala.

  16. Association of three common single nucleotide polymorphisms of ATP binding cassette G8 gene with gallstone disease: a meta-analysis.

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    Zhao-Yan Jiang

    Full Text Available BACKGROUND: In this study, we evaluated the association between these polymorphisms and gallstone disease using meta-analysis and compared the hepatic ABCG5/G8 mRNA expression and biliary lipids composition in patients with different genotypes of T400K and Y54C. METHODS: Data were analyzed using the Stata/SE 11.0 software and a random- effects model was applied irrespective of between-study heterogeneity. Hepatic mRNA expression of ABCG5/G8 genes in 182 patients with gallstone disease and 35 gallstone-free patients who underwent cholecystectomy were determined using real-time PCR. Genotypes of Y54C and T400K in the ABCG8 gene were determined by allelic discrimination using either genomic DNA or hepatic cDNA as template by Taqman assays. Biliary compostion in gallbladder bile was assayed in these patients as well. RESULTS: Ten papers including 13 cohorts were included for the final analysis. In the genotype model, the overall association between genotype with gallstone was significant for D19H (OR = 2.43, 95%CI: 2.23-2.64, P<0.001, and for Y54C (OR = 1.36, 95%CI: 1.01-1.83, P = 0.044, or T400K (OR = 1.17, 95%CI: 0.96-1.43. P = 0.110. In allele model, minor alleles of D19H polymorphism (allele D: OR = 2.25, 95%CI: 2.10-2.42, P<0.001 and of T400K polymorphism (allele K: OR = 1.18, 95%CI: 1.06-1.31, P<0.001 were related with an increased risk of gallstone disease. However, minor allele of Y54C polymorphism (allele Y, OR = 1.08, 95%CI: 0.96-1.21, P = 0.146 was not related with gallstone disease. I(2 statistics indicated no significant between-study heterogeneity for all genetic models for any of the three polymorphisms. Funnel plot and Egger's test suggested the absence of publication bias as well. However, no association of T400K and Y54C polymorphism with hepatic ABCG8/G5 mRNA expression or biliary lipids composition was found. CONCLUSIONS: Our study showed strong association of D19H polymorphism with gallstone disease. T400K and Y54C polymorphism, though to a less extent, may also relate with gallstone disease.

  17. ATP-binding cassette transporters are enriched in non-caveolar detergent-insoluble glycosphingolipid-enriched membrane domains (DIGs) in human multidrug-resistant cancer cells

    NARCIS (Netherlands)

    Hinrichs, JWJ; Klappe, K; Hummel, [No Value; Kok, JW

    2004-01-01

    In this study we show that P-glycoprotein in multi-drug-resistant 2780AD human ovarian carcinoma cells and multidrug resistance-associated protein 1 in multi-drug-resistant HT29(col) human colon carcinoma cells are predominantly located in Lubrol-based detergent-insoluble glycosphingolipid-enriched

  18. Hop resistance in the beer spoilage bacterium Lactobacillus brevis is mediated by the ATP-binding cassette multidrug transporter HorA

    NARCIS (Netherlands)

    Sakamoto, K; Margolles, A; van Veen, HW; Konings, WN

    2001-01-01

    Lactobacillus brevis is a major contaminant of spoiled beer. The organism can grow in beer in spite of the presence of antibacterial hop compounds that give the beer a bitter taste. The hop resistance in L. brevis is, at least in part, dependent on the expression of the horA gene. The deduced amino

  19. Tiaozhi Tongmai Granules reduce atherogenesis and promote the expression of ATP-binding cassette transporter A1 in rabbit atherosclerotic plaque macrophages and the liver

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    Qing Sun

    2014-07-01

    Conclusions: Tiaozhi Tongmai Granules appear to have an anti-atherogenic effect that is most likely mediated by simultaneously upregulating the protein expression of ABCA1 in rabbit atherosclerotic plaque macrophages and in the liver.

  20. Construction of deletion mutants in the phosphotransferase transport system and adenosine triphosphate-binding cassette transporters in Listeria monocytogenes and analysis of their growth under different stress conditions

    Directory of Open Access Journals (Sweden)

    Marina Ceruso

    2013-10-01

    Full Text Available Functional genomics approaches enable us to investigate the biochemical, cellular, and physiological properties of each gene product and are nowadays applied to enhance food safety by understanding microbial stress responses in food and host-pathogen interactions. Listeria monocytogenes is a food-borne pathogen that causes listeriosis and is difficult to eliminate this pathogen since it can survive under multiple stress conditions such as low pH and low temperature. Detailed studies are needed to determine its mode of action and to understand the mechanisms that protect the pathogen when it is subjected to stress. In this study, deletion mutants of phosphotransferase transport system genes (PTS and adenosine triphosphate(ATP-binding cassette transporters (ABC of Listeria monocytogenes F2365 were created using molecular techniques. These mutants and the wild-type were tested under different stress conditions, such as in solutions with different NaCl concentration, pH value and for nisin resistance. Results demonstrate that the behaviour of these deletion mutants is different from the wild type. In particular, deleted genes may be involved in L. monocytogenes resistance to nisin and to acid and salt concentrations. Functional genomics research on L. monocytogenes allows a better understanding of the genes related to stress responses and this knowledge may help in intervention strategies to control this food-borne pathogen. Furthermore, specific gene markers can be used to identify and subtype L. monocytogenes. Thus, future development of this study will focus on additional functional analyses of important stress response-related genes, as well as on methods for rapid and sensitive detection of L. monocytogenes such as using DNA microarrays.

  1. Gene expression profiling of cytochromes P450, ABC transporters and their principal transcription factors in the amygdala and prefrontal cortex of alcoholics, smokers and drug-free controls by qRT-PCR.

    Science.gov (United States)

    Toselli, Francesca; de Waziers, Isabelle; Dutheil, Mary; Vincent, Marc; Wilce, Peter A; Dodd, Peter R; Beaune, Philippe; Loriot, Marie-Anne; Gillam, Elizabeth M J

    2015-01-01

    1. Ethanol consumption and smoking alter the expression of certain drug-metabolizing enzymes and transporters, potentially influencing the tissue-specific effects of xenobiotics. 2. Amygdala (AMG) and prefrontal cortex (PFC) are brain regions that modulate the effects of alcohol and smoking, yet little is known about the expression of cytochrome P450 enzymes (P450s) and ATP-binding cassette (ABC) transporters in these tissues. 3. Here, we describe the first study on the expression of 19 P450s, their redox partners, three ABC transporters and four related transcription factors in the AMG and PFC of smokers and alcoholics by quantitative RT-PCR. 4. CYP1A1, CYP1B1, CYP2B6, CYP2C8, CYP2C18, CYP2D6, CYP2E1, CYP2J2, CYP2S1, CYP2U1, CYP4X1, CYP46, adrenodoxin and NADPH-P450 reductase, ABCB1, ABCG2, ABCA1, and transcription factors aryl hydrocarbon receptor AhR and proliferator-activated receptor α were quantified in both areas. CYP2A6, CYP2C9, CYP2C19, CYP3A4, CYP3A5, adrenodoxin reductase and the nuclear receptors pregnane X receptor and constitutive androstane receptor were detected but below the limit of quantification. CYP1A2 and CYP2W1 were not detected. 5. Adrenodoxin expression was elevated in all case groups over controls, and smokers showed a trend toward higher CYP1A1 and CYP1B1 expression. 6. Our study shows that most xenobiotic-metabolizing P450s and associated redox partners, transporters and transcription factors are expressed in human AMG and PFC.

  2. Screening of miRNA regulating ABCE1 gene in non-small-cell lung cancer%ABCE1基因在非小细胞肺癌内相关调节miRNA的筛选

    Institute of Scientific and Technical Information of China (English)

    田野; 刘思洋; 许辉; 姜文军; 赵希彤; 王晴; 田大力

    2015-01-01

    Objective To screen the miRNAs regulating ATP-binding cassette transporter E1(ABCE1) gene in non-small-cell lung cancer, and explore new strategies in lung cancer diagnosis and therapy. Methods The 20 patients with non-small-cell lung cancer(11 squamous cell carcinoma and 9 adenocarcinoma) were enrolled, included 13 males and 7 females, which aged 45-73 years old with mean age of 62.9 years old. Bioinformatics was used to predict the miRNAs regulated ABCE1 gene;statistical analysis was then done to screen out the purpose miRNA by real-time quantitative PCR(RT-Q-PCR) and detected miRNAs and ABCE1 mRNA and protein. Results The result of bioinformatics software predicted that seven miRNAs had highest possibility to regulate ABCE1 gene, which were miR-29a/b/c, miR-135a/b, miR-203 and miR-141. The expression of miR-29a/b/c, miR-135a, miR-203, especially miR-135a and miR-29c in carcinoma tissues, compared to those in pericarcinomatous tissues experienced decrease to different degrees, while the expression of mRNA and protein of ABCE1 increased in carcinoma tissues ( P < 0.05). Moreover, there appeared to be negative correlation between miR-135a and ABCE1 in lung cancer tissues(r=-0.665,P=0.001). Conclusion It is demonstrated that the miR-135a negatively regulates ABCE1 gene, and the combination of them might be the new target for diagnosis and treatment of non-small-cell lung cancer.%目的:筛选ATP结合盒E1(ABCE1)基因的相关调节miRNA,为诊治肺癌提供新思路。方法选取20例非小细胞肺癌患者,其中男性13例,女性7例;年龄45~73岁,平均年龄62.9岁。鳞癌11例,腺癌9例。应用生物信息学预测ABCE1基因上游的miRNA,通过实时定量聚合酶链反应(RT-Q-PCR)及免疫组织化学方法,对标本非小细胞癌组织和癌旁组织进行检测,并进行统计学分析,从中筛选出目的miRNA。结果生物信息软件预测7个最有可能调节 ABCE1基因的miRNA,分别为miR-29a

  3. A man-made ATP-binding protein evolved independent of nature causes abnormal growth in bacterial cells.

    Directory of Open Access Journals (Sweden)

    Joshua M Stomel

    Full Text Available Recent advances in de novo protein evolution have made it possible to create synthetic proteins from unbiased libraries that fold into stable tertiary structures with predefined functions. However, it is not known whether such proteins will be functional when expressed inside living cells or how a host organism would respond to an encounter with a non-biological protein. Here, we examine the physiology and morphology of Escherichia coli cells engineered to express a synthetic ATP-binding protein evolved entirely from non-biological origins. We show that this man-made protein disrupts the normal energetic balance of the cell by altering the levels of intracellular ATP. This disruption cascades into a series of events that ultimately limit reproductive competency by inhibiting cell division. We now describe a detailed investigation into the synthetic biology of this man-made protein in a living bacterial organism, and the effect that this protein has on normal cell physiology.

  4. Mycobacterium tuberculosis universal stress protein Rv2623 regulates bacillary growth by ATP-Binding: requirement for establishing chronic persistent infection.

    Directory of Open Access Journals (Sweden)

    Joshua E Drumm

    2009-05-01

    Full Text Available Tuberculous latency and reactivation play a significant role in the pathogenesis of tuberculosis, yet the mechanisms that regulate these processes remain unclear. The Mycobacterium tuberculosisuniversal stress protein (USP homolog, rv2623, is among the most highly induced genes when the tubercle bacillus is subjected to hypoxia and nitrosative stress, conditions thought to promote latency. Induction of rv2623 also occurs when M. tuberculosis encounters conditions associated with growth arrest, such as the intracellular milieu of macrophages and in the lungs of mice with chronic tuberculosis. Therefore, we tested the hypothesis that Rv2623 regulates tuberculosis latency. We observed that an Rv2623-deficient mutant fails to establish chronic tuberculous infection in guinea pigs and mice, exhibiting a hypervirulence phenotype associated with increased bacterial burden and mortality. Consistent with this in vivo growth-regulatory role, constitutive overexpression of rv2623 attenuates mycobacterial growth in vitro. Biochemical analysis of purified Rv2623 suggested that this mycobacterial USP binds ATP, and the 2.9-A-resolution crystal structure revealed that Rv2623 engages ATP in a novel nucleotide-binding pocket. Structure-guided mutagenesis yielded Rv2623 mutants with reduced ATP-binding capacity. Analysis of mycobacteria overexpressing these mutants revealed that the in vitro growth-inhibitory property of Rv2623 correlates with its ability to bind ATP. Together, the results indicate that i M. tuberculosis Rv2623 regulates mycobacterial growth in vitro and in vivo, and ii Rv2623 is required for the entry of the tubercle bacillus into the chronic phase of infection in the host; in addition, iii Rv2623 binds ATP; and iv the growth-regulatory attribute of this USP is dependent on its ATP-binding activity. We propose that Rv2623 may function as an ATP-dependent signaling intermediate in a pathway that promotes persistent infection.

  5. The Q Motif Is Involved in DNA Binding but Not ATP Binding in ChlR1 Helicase.

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    Hao Ding

    Full Text Available Helicases are molecular motors that couple the energy of ATP hydrolysis to the unwinding of structured DNA or RNA and chromatin remodeling. The conversion of energy derived from ATP hydrolysis into unwinding and remodeling is coordinated by seven sequence motifs (I, Ia, II, III, IV, V, and VI. The Q motif, consisting of nine amino acids (GFXXPXPIQ with an invariant glutamine (Q residue, has been identified in some, but not all helicases. Compared to the seven well-recognized conserved helicase motifs, the role of the Q motif is less acknowledged. Mutations in the human ChlR1 (DDX11 gene are associated with a unique genetic disorder known as Warsaw Breakage Syndrome, which is characterized by cellular defects in genome maintenance. To examine the roles of the Q motif in ChlR1 helicase, we performed site directed mutagenesis of glutamine to alanine at residue 23 in the Q motif of ChlR1. ChlR1 recombinant protein was overexpressed and purified from HEK293T cells. ChlR1-Q23A mutant abolished the helicase activity of ChlR1 and displayed reduced DNA binding ability. The mutant showed impaired ATPase activity but normal ATP binding. A thermal shift assay revealed that ChlR1-Q23A has a melting point value similar to ChlR1-WT. Partial proteolysis mapping demonstrated that ChlR1-WT and Q23A have a similar globular structure, although some subtle conformational differences in these two proteins are evident. Finally, we found ChlR1 exists and functions as a monomer in solution, which is different from FANCJ, in which the Q motif is involved in protein dimerization. Taken together, our results suggest that the Q motif is involved in DNA binding but not ATP binding in ChlR1 helicase.

  6. Mycobacterium tuberculosis Universal Stress Protein Rv2623 Regulates Bacillary Growth by ATP Binding: Requirement for Establishing Chronic Persistent Infection

    Energy Technology Data Exchange (ETDEWEB)

    Drumm, J.; Mi, K; Bilder, P; Sun, M; Lim, J; Bielefeldt-Ohmann, H; Basaraba, R; So, M; Zhu, G; et. al.

    2009-01-01

    Tuberculous latency and reactivation play a significant role in the pathogenesis of tuberculosis, yet the mechanisms that regulate these processes remain unclear. The Mycobacterium tuberculosisuniversal stress protein (USP) homolog, rv2623, is among the most highly induced genes when the tubercle bacillus is subjected to hypoxia and nitrosative stress, conditions thought to promote latency. Induction of rv2623 also occurs when M. tuberculosis encounters conditions associated with growth arrest, such as the intracellular milieu of macrophages and in the lungs of mice with chronic tuberculosis. Therefore, we tested the hypothesis that Rv2623 regulates tuberculosis latency. We observed that an Rv2623-deficient mutant fails to establish chronic tuberculous infection in guinea pigs and mice, exhibiting a hypervirulence phenotype associated with increased bacterial burden and mortality. Consistent with this in vivo growth-regulatory role, constitutive overexpression of rv2623 attenuates mycobacterial growth in vitro. Biochemical analysis of purified Rv2623 suggested that this mycobacterial USP binds ATP, and the 2.9-A-resolution crystal structure revealed that Rv2623 engages ATP in a novel nucleotide-binding pocket. Structure-guided mutagenesis yielded Rv2623 mutants with reduced ATP-binding capacity. Analysis of mycobacteria overexpressing these mutants revealed that the in vitro growth-inhibitory property of Rv2623 correlates with its ability to bind ATP. Together, the results indicate that i M. tuberculosis Rv2623 regulates mycobacterial growth in vitro and in vivo, and ii Rv2623 is required for the entry of the tubercle bacillus into the chronic phase of infection in the host; in addition, iii Rv2623 binds ATP; and iv the growth-regulatory attribute of this USP is dependent on its ATP-binding activity. We propose that Rv2623 may function as an ATP-dependent signaling intermediate in a pathway that promotes persistent infection.

  7. DDRT-PCR Analysis of Wheat Roots Under Iron-Deficient Condition and Differential Expression of ABC Gene

    Institute of Scientific and Technical Information of China (English)

    YIN Li-ping; LIU Wei-zhong; LIU Xiang-lin; HUANG Qin-ni; ZHANG Fu-suo

    2002-01-01

    Differential expression of gene in iron-efficient wheat cultivar Jing411 and iron-inefficient cul-tivar Sanshumai3 under iron-deficiency and iron-sufficiency conditions was revealed by differential display re-verse transcript PCR (DDRT-PCR) method. Northern blotting was carried out using ATP-binding transporter(ABC) cDNA obtained from DDRT-PCR products of the cuitivar Jing411 as probe. Our results suggested thatABC gene expression was suppressed under iron-deficiency condition.

  8. Automated cassette-to-cassette substrate handling system

    Science.gov (United States)

    Kraus, Joseph Arthur; Boyer, Jeremy James; Mack, Joseph; DeChellis, Michael; Koo, Michael

    2014-03-18

    An automated cassette-to-cassette substrate handling system includes a cassette storage module for storing a plurality of substrates in cassettes before and after processing. A substrate carrier storage module stores a plurality of substrate carriers. A substrate carrier loading/unloading module loads substrates from the cassette storage module onto the plurality of substrate carriers and unloads substrates from the plurality of substrate carriers to the cassette storage module. A transport mechanism transports the plurality of substrates between the cassette storage module and the plurality of substrate carriers and transports the plurality of substrate carriers between the substrate carrier loading/unloading module and a processing chamber. A vision system recognizes recesses in the plurality of substrate carriers corresponding to empty substrate positions in the substrate carrier. A processor receives data from the vision system and instructs the transport mechanism to transport substrates to positions on the substrate carrier in response to the received data.

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

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    Marc S Schwartz

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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

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

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    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

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

    Science.gov (United States)

    Tay, Wee Tek; Mahon, Rod J.; Heckel, David G.; Walsh, Thomas K.; Downes, Sharon; James, William J.; Lee, Sui-Fai; Reineke, Annette; Williams, Adam K.; Gordon, Karl H. J.

    2015-01-01

    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 detailed mode

  12. 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 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.

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

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    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

  14. Characterization of a PDR type ABC transporter gene from wheat (Triticum aestivum L.)

    Institute of Scientific and Technical Information of China (English)

    SHANG Yi; XIAO Jin; MA LuLin; WANG HaiYan; QI ZengJun; CHEN PeiDu; LIU DaJun; WANG XiuE

    2009-01-01

    DON,as a virulence factor,plays an important role in the infection of Fusarium graminearum in wheat.The infection ability of F. graminearum depends on its capacity of producing DON. The production of DON by F. graminearum is significantly decreased in the wheat varieties with scab resistance. In this study,GeneChip analysis indicated that an EST encoding an ATP-binding cassette (ABC) transporter was up-regulated by 45 times in a wheat landrace Wangshuibai,which is resistant to DON accumulation.A pair of EST-derived primers were designed based on the EST sequence,and a clone was then isolated from a wheat genomic DNA TAC library. The TAC clone was sequenced using chromosome walking and gene prediction was conducted using Softberry. A cDNA clone of this gene was subsequently isolated from Wangshuibai induced by DON using gene-specific primers designed according to the untranslated sequence of the gene. The genome size of the gene is 7377 bp,consisting of 19 exons with coding sequences of 4308 bp. It encodes a protein with 1435 amino acid residues and the calculated molecular weight is about 161 kD. BLAST analysis indicated that the gene may belong to pleiotropic drug resistance (PDR) sub-family,and hence designated as TaPDR1 (Triticum aestivum pleiotropic drug resistance). TaPDR1 was located on chromosome 5A of wheat using nulliaomic-tetrasomic lines of Chinese Spring. TaPDR1 was up-regulated by induction of both DON and F. graminearum. Expression patterns of TaPDR1 were different in wild-type Wangshuibai and the fast-neutron induced Wangshuibai mutant lacking FHB1,a major QTL of FHB resistance and DON resistance in chromosome arm 3BS. These results suggested that TaPDR1 might be a candidate gene responsible for DON accumulation resistance. The expression profile showed that TaPDR1 expression was neither induced by hormones typically involved in biotic stress,such as JA and SA,nor by abiotic stresses,such as heat,cold,wounding and NaCI. However,TaPDR1 expression was

  15. Simulated microgravity alters the expression of cytoskeleton- and ATP-binding-related genes in MLO-Y4 osteocytes

    Science.gov (United States)

    Chen, Zhihao; Zhao, Fan; Qi, Yiduo; Hu, Lifang; Li, Dijie; Yin, Chong; Su, Peihong; Zhang, Yan; Ma, Jianhua; Qian, Jing; Zhou, Hongpo; Zou, Yiwei; Qian, Airong

    2016-12-01

    Bone undergoes dynamic modelling and remodelling processes, and it requires gravity-mediated mechanical stimulation for the maintenance of mineral content and structure. Osteocytes are the most commonly found cells in the mature bone, and they are sensitive to mechanical changes. The purpose of this study was to investigate the effects of microgravity simulated with a random position machine (RPM) on the gene expression profile of osteocytes. Genes sensitive to RPM treatment were sorted on the basis of biological processes, interactions and signalling pathways. Overall, 504 differentially expressed genes (DEGs) in osteocytes cultured under RPM conditions were found. The DEGs were further analysed using bioinformatics tools such as DAVID and iReport. A total of 15 ATP-binding and cytoskeleton-related genes were further confirmed by quantitative real-time PCR (qRT-PCR). Our findings demonstrate that the RPM affected the expression of genes involved in cytoskeleton remodelling and the energy-transfer process in osteocytes. The identification of mechanosensitive genes may enhance our understanding of the roles of osteocytes in mechanosensation and may provide some potential targets for preventing and treating bone-related diseases.

  16. Solution structure and function in trifluoroethanol of PP-50, an ATP-binding peptide from F1ATPase.

    Science.gov (United States)

    Chuang, W J; Abeygunawardana, C; Gittis, A G; Pedersen, P L; Mildvan, A S

    1995-05-10

    PP-50, a synthetic peptide, based on residues 141-190 of the beta-subunit of mitochondrial F1ATPase, containing the GX4GKT consensus sequence for nucleoside triphosphate binding, binds ATP tightly (Kd = 17.5 microM) as found by fluorescence titration at pH 4.0. CD and 2D proton NMR studies at pH 4.0 revealed two beta-turns, regions of extended secondary structure, transient tertiary structure, and flexibility in the GX4GKT region (W.J. Chuang, C. Abeygunawardana, P. L. Pedersen, and A. S. Mildvan, 1992, Biochemistry 31, 7915-7921). CD titration of PP-50 with trifluoroethanol (TFE) reveals a decrease in ellipticity at 208 and 222 nm, saturating at 25% TFE. Computer analysis indicates that 25% TFE increases the helix content from 5.8 to 28.6%, decreases the beta-structure from 30.2 to 20.2% and decreases the coil content from 64 to 51.2%. Fluorescence titrations of H2ATP2- with PP-50 in 25% TFE yields a Kd of 7.3 microM, 2.4-fold tighter than in H2O, probably due to TFE increasing the activity of H2ATP2- . PP-50 completely quenches the fluorescence of H2ATP2- in 25% TFE, while in H2O the fluorescence quenching is only 62%. In H2O the binding of H2ATP2- increases the structure of PP-50 as detected by CD, but in 25% TFE no significant change in CD is found on binding either H2ATP2- or Mg2+ HATP (Kd = 14 microM). The complete proton NMR spectrum of PP-50 in 25% TFE has been assigned. The solution structure, determined by distance geometry, molecular dynamics with simulated annealing, and energy minimization, consists of a coil (residues 1-8), a strand (residues 9-12), a loop (residues 13-22) containing the GX4GKT consensus sequence (residues 16-23), an alpha-helix (residues 23-36), a turn (residues 38-41), and a coil (residues 42-50), similar to that of the corresponding region of the X-ray structure of F1ATPase (J.P. Abrahams, A.G.W. Leslie, R. Lutter, and J. E. Walker, 1994 Nature 370, 621-628) and to the structure of a homologous peptide from the ATP-binding site of

  17. Discovery of a novel allosteric inhibitor-binding site in ERK5: comparison with the canonical kinase hinge ATP-binding site.

    Science.gov (United States)

    Chen, Hongming; Tucker, Julie; Wang, Xiaotao; Gavine, Paul R; Phillips, Chris; Augustin, Martin A; Schreiner, Patrick; Steinbacher, Stefan; Preston, Marian; Ogg, Derek

    2016-05-01

    MAP kinases act as an integration point for multiple biochemical signals and are involved in a wide variety of cellular processes such as proliferation, differentiation, regulation of transcription and development. As a member of the MAP kinase family, ERK5 (MAPK7) is involved in the downstream signalling pathways of various cell-surface receptors, including receptor tyrosine kinases and G protein-coupled receptors. In the current study, five structures of the ERK5 kinase domain co-crystallized with ERK5 inhibitors are reported. Interestingly, three of the compounds bind at a novel allosteric binding site in ERK5, while the other two bind at the typical ATP-binding site. Binding of inhibitors at the allosteric site is accompanied by displacement of the P-loop into the ATP-binding site and is shown to be ATP-competitive in an enzymatic assay of ERK5 kinase activity. Kinase selectivity data show that the most potent allosteric inhibitor exhibits superior kinase selectivity compared with the two inhibitors that bind at the canonical ATP-binding site. An analysis of these structures and comparison with both a previously published ERK5-inhibitor complex structure (PDB entry 4b99) and the structures of three other kinases (CDK2, ITK and MEK) in complex with allosteric inhibitors are presented.

  18. Main: SB3NPABC1 [PLACE

    Lifescience Database Archive (English)

    Full Text Available SB3NPABC1 S000434 27-Jan-2004 (last modified) kehi Sclareol box3 (SB3) found at -21...6 of a plasma membrane ATP binding cassette (ABC) transporter gene (NpABC1) in N. plumbaginifolia; Mutation ...in SB3 completely abolished sclareolide-mediated expression; See S ; sclareol; ABC; transporter; SB3; Nicotiana plumbaginifolia (tobacco); TTATGAACAGTAATT ...

  19. Main: SB1NPABC1 [PLACE

    Lifescience Database Archive (English)

    Full Text Available SB1NPABC1 S000435 27-Jan-2004 (last modified) kehi Sclareol box1 (SB1) found at -82...7 of a plasma membrane ATP binding cassette (ABC) transporter gene (NpABC1) in N. plumbaginifolia; Mutation ...in SB3 completely abolished sclareolide-mediated expression; See S ; scalareol; diterpene; ABC; transporter; Nicotiana plumbaginifolia (tobacco); CACTAACACAAAGTAA ...

  20. 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 BACKGROUND: 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. METHODS/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: The CT of Pxa2p is involved in its interaction with Pxa1p and in transporter function. This concept may be applied to human ALDP studies

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

    Science.gov (United States)

    Raza, Ali; Kopp, Steven R; Bagnall, Neil H; Jabbar, Abdul; Kotze, Andrew C

    2016-08-01

    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.

  2. 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.

  3. 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

  4. Structural models of zebrafish (Danio rerio NOD1 and NOD2 NACHT domains suggest differential ATP binding orientations: insights from computational modeling, docking and molecular dynamics simulations.

    Directory of Open Access Journals (Sweden)

    Jitendra Maharana

    Full Text Available Nucleotide-binding oligomerization domain-containing protein 1 (NOD1 and NOD2 are cytosolic pattern recognition receptors playing pivotal roles in innate immune signaling. NOD1 and NOD2 recognize bacterial peptidoglycan derivatives iE-DAP and MDP, respectively and undergoes conformational alternation and ATP-dependent self-oligomerization of NACHT domain followed by downstream signaling. Lack of structural adequacy of NACHT domain confines our understanding about the NOD-mediated signaling mechanism. Here, we predicted the structure of NACHT domain of both NOD1 and NOD2 from model organism zebrafish (Danio rerio using computational methods. Our study highlighted the differential ATP binding modes in NOD1 and NOD2. In NOD1, γ-phosphate of ATP faced toward the central nucleotide binding cavity like NLRC4, whereas in NOD2 the cavity was occupied by adenine moiety. The conserved 'Lysine' at Walker A formed hydrogen bonds (H-bonds and Aspartic acid (Walker B formed electrostatic interaction with ATP. At Sensor 1, Arg328 of NOD1 exhibited an H-bond with ATP, whereas corresponding Arg404 of NOD2 did not. 'Proline' of GxP motif (Pro386 of NOD1 and Pro464 of NOD2 interacted with adenine moiety and His511 at Sensor 2 of NOD1 interacted with γ-phosphate group of ATP. In contrast, His579 of NOD2 interacted with the adenine moiety having a relatively inverted orientation. Our findings are well supplemented with the molecular interaction of ATP with NLRC4, and consistent with mutagenesis data reported for human, which indicates evolutionary shared NOD signaling mechanism. Together, this study provides novel insights into ATP binding mechanism, and highlights the differential ATP binding modes in zebrafish NOD1 and NOD2.

  5. Characterization of a novel domain ‘GATE’ in the ABC protein DrrA and its role in drug efflux by the DrrAB complex

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Han; Rahman, Sadia; Li, Wen; Fu, Guoxing; Kaur, Parjit, E-mail: pkaur@gsu.edu

    2015-03-27

    A novel domain, GATE (Glycine-loop And Transducer Element), is identified in the ABC protein DrrA. This domain shows sequence and structural conservation among close homologs of DrrA as well as distantly-related ABC proteins. Among the highly conserved residues in this domain are three glycines, G215, G221 and G231, of which G215 was found to be critical for stable expression of the DrrAB complex. Other conserved residues, including E201, G221, K227 and G231, were found to be critical for the catalytic and transport functions of the DrrAB transporter. Structural analysis of both the previously published crystal structure of the DrrA homolog MalK and the modeled structure of DrrA showed that G215 makes close contacts with residues in and around the Walker A motif, suggesting that these interactions may be critical for maintaining the integrity of the ATP binding pocket as well as the complex. It is also shown that G215A or K227R mutation diminishes some of the atomic interactions essential for ATP catalysis and overall transport function. Therefore, based on both the biochemical and structural analyses, it is proposed that the GATE domain, located outside of the previously identified ATP binding and hydrolysis motifs, is an additional element involved in ATP catalysis. - Highlights: • A novel domain ‘GATE’ is identified in the ABC protein DrrA. • GATE shows high sequence and structural conservation among diverse ABC proteins. • GATE is located outside of the previously studied ATP binding and hydrolysis motifs. • Conserved GATE residues are critical for stability of DrrAB and for ATP catalysis.

  6. The rem Mutations in the ATP-Binding Groove of the Rad3/XPD Helicase Lead to Xeroderma pigmentosum-Cockayne Syndrome-Like Phenotypes

    Science.gov (United States)

    Montelone, Beth A.; Aguilera, Andrés

    2014-01-01

    The eukaryotic TFIIH complex is involved in Nucleotide Excision Repair and transcription initiation. We analyzed three yeast mutations of the Rad3/XPD helicase of TFIIH known as rem (recombination and mutation phenotypes). We found that, in these mutants, incomplete NER reactions lead to replication fork breaking and the subsequent engagement of the homologous recombination machinery to restore them. Nevertheless, the penetrance varies among mutants, giving rise to a phenotype gradient. Interestingly, the mutations analyzed reside at the ATP-binding groove of Rad3 and in vivo experiments reveal a gain of DNA affinity upon damage of the mutant Rad3 proteins. Since mutations at the ATP-binding groove of XPD in humans are present in the Xeroderma pigmentosum-Cockayne Syndrome (XP-CS), we recreated rem mutations in human cells, and found that these are XP-CS-like. We propose that the balance between the loss of helicase activity and the gain of DNA affinity controls the capacity of TFIIH to open DNA during NER, and its persistence at both DNA lesions and promoters. This conditions NER efficiency and transcription resumption after damage, which in human cells would explain the XP-CS phenotype, opening new perspectives to understand the molecular basis of the role of XPD in human disease. PMID:25500814

  7. Optimizing expression and purification of an ATP-binding gene gsiA from Escherichia coli k-12 by using GFP fusion

    Directory of Open Access Journals (Sweden)

    Zhongshan Wang

    2011-01-01

    Full Text Available The cloning, expression and purification of the glutathione (sulfur import system ATP-binding protein (gsiA was carried out. The coding sequence of Escherichia coli gsiA, which encodes the ATP-binding protein of a glutathione importer, was amplified by PCR, and then inserted into a prokaryotic expression vector pWaldo-GFPe harboring green fluorescent protein (GFP reporter gene. The resulting recombinant plasmid pWaldo-GFP-GsiA was transformed into various E. coli strains, and expression conditions were optimized. The effect of five E. coli expression strains on the production of the recombinant gsiA protein was evaluated. E. coli BL21 (DE3 was found to be the most productive strain for GsiA-GFP fusion-protein expression, most of which was insoluble fraction. However, results from in-gel and Western blot analysis suggested that expression of recombinant GsiA in Rosetta (DE3 provides an efficient source in soluble form. By using GFP as reporter, the most suitable host strain was conveniently obtained, whereby optimizing conditions for overexpression and purification of the proteins for further functional and structural studies, became, not only less laborious, but also time-saving.

  8. Long-range coupling between the extracellular gates and the intracellular ATP binding domains of multidrug resistance protein pumps and cystic fibrosis transmembrane conductance regulator channels.

    Science.gov (United States)

    Wei, Shipeng; Roessler, Bryan C; Icyuz, Mert; Chauvet, Sylvain; Tao, Binli; Hartman, John L; Kirk, Kevin L

    2016-03-01

    The ABCC transporter subfamily includes pumps, the long and short multidrug resistance proteins (MRPs), and an ATP-gated anion channel, the cystic fibrosis transmembrane conductance regulator (CFTR). We show that despite their thermodynamic differences, these ABCC transporter subtypes use broadly similar mechanisms to couple their extracellular gates to the ATP occupancies of their cytosolic nucleotide binding domains. A conserved extracellular phenylalanine at this gate was a prime location for producing gain of function (GOF) mutants of a long MRP in yeast (Ycf1p cadmium transporter), a short yeast MRP (Yor1p oligomycin exporter), and human CFTR channels. Extracellular gate mutations rescued ATP binding mutants of the yeast MRPs and CFTR by increasing ATP sensitivity. Control ATPase-defective MRP mutants could not be rescued by this mechanism. A CFTR double mutant with an extracellular gate mutation plus a cytosolic GOF mutation was highly active (single-channel open probability >0.3) in the absence of ATP and protein kinase A, each normally required for CFTR activity. We conclude that all 3 ABCC transporter subtypes use similar mechanisms to couple their extracellular gates to ATP occupancy, and highly active CFTR channels that bypass defects in ATP binding or phosphorylation can be produced.

  9. ATP-binding site of adenylate kinase: mechanistic implications of its homology with ras-encoded p21, F1-ATPase, and other nucleotide-binding proteins.

    Science.gov (United States)

    Fry, D C; Kuby, S A; Mildvan, A S

    1986-02-01

    The MgATP binding site of adenylate kinase, located by a combination of NMR and x-ray diffraction, is near three protein segments, five to seven amino acids in length, that are homologous in sequence to segments found in other nucleotide-binding phosphotransferases, such as myosin and F1-ATPase, ras p21 and transducin GTPases, and cAMP-dependent and src protein kinases, suggesting equivalent mechanistic roles of these segments in all of these proteins. Segment 1 is a glycine-rich flexible loop that, on adenylate kinase, may control access to the ATP-binding site by changing its conformation. Segment 2 is an alpha-helix containing two hydrophobic residues that interact with the adenine-ribose moiety of ATP, and a lysine that may bind to the beta- and gamma-phosphates of ATP. Segment 3 is a hydrophobic strand of parallel beta-pleated sheet, terminated by a carboxylate, that flanks the triphosphate binding site. The various reported mutations of ras p21 that convert it to a transforming agent all appear to involve segment 1, and such substitutions may alter the properties of p21 by hindering a conformational change at this segment. In F1-ATPase, the flexible loop may, by its position, control both the accessibility and the ATP/ADP equilibrium constant on the enzyme.

  10. Thermodynamics of ABC transporters.

    Science.gov (United States)

    Zhang, Xuejun C; Han, Lei; Zhao, Yan

    2016-01-01

    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.

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

    OpenAIRE

    Iwao Ohtsu; Yusuke Kawano; Marina Suzuki; Susumu Morigasaki; Kyohei Saiki; Shunsuke Yamazaki; Gen Nonaka; Hiroshi Takagi

    2015-01-01

    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 (K m = 1.1 μM) that is ...

  12. Decipher the mechanisms of protein conformational changes induced by nucleotide binding through free-energy landscape analysis: ATP binding to Hsp70.

    Directory of Open Access Journals (Sweden)

    Adrien Nicolaï

    Full Text Available ATP regulates the function of many proteins in the cell by transducing its binding and hydrolysis energies into protein conformational changes by mechanisms which are challenging to identify at the atomic scale. Based on molecular dynamics (MD simulations, a method is proposed to analyze the structural changes induced by ATP binding to a protein by computing the effective free-energy landscape (FEL of a subset of its coordinates along its amino-acid sequence. The method is applied to characterize the mechanism by which the binding of ATP to the nucleotide-binding domain (NBD of Hsp70 propagates a signal to its substrate-binding domain (SBD. Unbiased MD simulations were performed for Hsp70-DnaK chaperone in nucleotide-free, ADP-bound and ATP-bound states. The simulations revealed that the SBD does not interact with the NBD for DnaK in its nucleotide-free and ADP-bound states whereas the docking of the SBD was found in the ATP-bound state. The docked state induced by ATP binding found in MD is an intermediate state between the initial nucleotide-free and final ATP-bound states of Hsp70. The analysis of the FEL projected along the amino-acid sequence permitted to identify a subset of 27 protein internal coordinates corresponding to a network of 91 key residues involved in the conformational change induced by ATP binding. Among the 91 residues, 26 are identified for the first time, whereas the others were shown relevant for the allosteric communication of Hsp70 s in several experiments and bioinformatics analysis. The FEL analysis revealed also the origin of the ATP-induced structural modifications of the SBD recently measured by Electron Paramagnetic Resonance. The pathway between the nucleotide-free and the intermediate state of DnaK was extracted by applying principal component analysis to the subset of internal coordinates describing the transition. The methodology proposed is general and could be applied to analyze allosteric communication in

  13. 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 a

  14. Effect of (mixtures of) flavonoids on the in vitro and in vivo bioavailability of 2-mino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) : a biologically based modelling approach

    NARCIS (Netherlands)

    Schutte, M.E.

    2007-01-01

    The transport of food ingredients across the intestinal epithelium is an important factor determining the absorption upon oral intake. Uptake of compounds in the intestine may be influenced by transport proteins such as the ATP binding cassette transporters (ABC transporters). ABC transporters have

  15. Role of ABC transporters in fluoropyrimidine-based chemotherapy response.

    Science.gov (United States)

    Nies, Anne T; Magdy, Tarek; Schwab, Matthias; Zanger, Ulrich M

    2015-01-01

    Since over 50 years, 5-fluorouracil (5-FU) is in use as backbone of chemotherapy treatment regimens for a wide range of cancers including colon, breast, and head and neck carcinomas. However, drug resistance and severe toxicities such as mucositis, diarrhea, neutropenia, and vomiting in up to 40% of treated patients often lead to dose limitation or treatment discontinuation. Because the oral bioavailability of 5-FU is unpredictable and highly variable, 5-FU is commonly administered intravenously. To overcome medical complications and inconvenience associated with intravenous administration, the oral prodrugs capecitabine and tegafur have been developed. Both fluoropyrimidines are metabolically converted intracellularly to 5-FU, which then needs metabolic activation to exert its damaging activity on RNA and DNA. The low response rates of 10-15% of 5-FU monotherapy can be improved by combination regimens of infusional 5-FU and leucovorin together with oxaliplatin (FOLFOX) or irinotecan (FOLFIRI), thereby increasing response rates to 30-40%. The impact of metabolizing enzymes in the development of fluoropyrimidine toxicity and resistance has been studied in great detail. In addition, membrane drug transporters, which are critical determinants of intracellular drug concentrations, may play a role in occurrence of toxicity and development of resistance against fluoropyrimidine-based therapy as well. This review therefore summarizes current knowledge on the role of drug transporters with particular focus on ATP-binding cassette transporters in fluoropyrimidine-based chemotherapy response.

  16. Inhibiting NF-K B increases cholesterol efflux from THP-1 derived- foam cells treated with Angll via up-regulating the expression of ATP-binding cassette transporter A1

    Institute of Scientific and Technical Information of China (English)

    Kun Liu; Yanfu Wang; Zhijian Chen; Yuhua Liao; Xiang Gao; Jian Chen

    2008-01-01

    Objective:To study the role of nuclear factor-kappa B(NF- K B) in cholesterol efflux from THP-I derived-foam cells treated with Angiotensin Ⅱ (Ang Ⅱ ). Methods:Cultured THP-l derived-foam cells were treated with Ang Ⅱ or preincubated with tosyl-phenylalan inechloromethyl-ketone(TPCK) NF-K B inhibitor. The levels of activated NF-K B in the cells were examined by sandwich ELISA. Cellular cholesterol content was studied by electron microscopy scanning and zymochemistry via fluorospectrophotometer and cholesterol efflux was detected by scintillation counting technique. ABCAI mRNA and protein were quantified by RT-PCR and Western blotting. Results:Addition of TPCK to the cells before Ang Ⅱ stimulation attenuated the response of NF- K B p65 nuclear translocation induced by Ang Ⅱ and showed no peak in foam cells group and caused a reduction in cholesterol content and an increase in cholesterol effiux by 24.1%(P < 0.05) and 41.1%(P < 0.05) respectively, when compared with Ang Ⅱ group. In accordance, the ABCAl mRNA and protein were increased by 30% and 19%(P< 0.05) respectively, when compared with Ang Ⅱ group. Conclusion:Ang Ⅱ can down- regulate ABCAI in THP-l derived-foam cells via NF- K B, which leads to less cholesterol effiux and the increase of cholesterol content with the consequence of the promotion of atherosclerosis.

  17. EFFECTS OF ANTHOCYANIN ON ATP BINDING CASSETTE TRANSPORTER G1 EXPRESSION AND ANALYSIS OF THE MECHANISMS%花色苷对THP-1细胞中ABCG1表达的影响及机制分析

    Institute of Scientific and Technical Information of China (English)

    张英慧; 董华强; 钟希琼; 黄剑波

    2011-01-01

    目的 研究花色苷矢车菊素-3-O-β-葡萄糖苷(C3G)对人巨噬细胞THP-1中ABCG1表达的影响,并分析相关作用机制.方法 以C3G干预培养诱导分化的THP-1细胞,荧光实时定量RT-PCR检测ATP结合盒式转运蛋白G1(ABCG1)以及其直接调节因子肝脏X受体α(liver X receptotα,LXRα)的mRNA表达,时间分辨荧光共振能量转移(time-resolved fluorescence resonance energy transfer,TR-FRET)方法检测C3G与LXRα配体结合域的结合能力.结果 100μ mol/L C3G处理THP-1细胞16 h显著增加了ABCG1 mRNA的表达(为对照组的1.98倍,P<0.05);尽管在TR-FRET试验中,C3G并未呈现典型的配体结合曲线,而50 μ mol/L和100μmol/L C3G显著增加了THP-1细胞中LXRαmRNA的表达(分别为对照组的2.21倍和2.83倍,P<0.05).结论 C3G促进了ABCG1表达,该机制可能通过增加核受体LXRαmRNA表达来实现.

  18. 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...

  19. 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).

  20. 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.

  1. Computer modelling reveals new conformers of the ATP binding loop of Na+/K+-ATPase involved in the transphosphorylation process of the sodium pump

    Directory of Open Access Journals (Sweden)

    Gracian Tejral

    2017-03-01

    Full Text Available Hydrolysis of ATP by Na+/K+-ATPase, a P-Type ATPase, catalyzing active Na+ and K+ transport through cellular membranes leads transiently to a phosphorylation of its catalytical α-subunit. Surprisingly, three-dimensional molecular structure analysis of P-type ATPases reveals that binding of ATP to the N-domain connected by a hinge to the P-domain is much too far away from the Asp369 to allow the transfer of ATP’s terminal phosphate to its aspartyl-phosphorylation site. In order to get information for how the transfer of the γ-phosphate group of ATP to the Asp369 is achieved, analogous molecular modeling of the M4–M5 loop of ATPase was performed using the crystal data of Na+/K+-ATPase of different species. Analogous molecular modeling of the cytoplasmic loop between Thr338 and Ile760 of the α2-subunit of Na+/K+-ATPase and the analysis of distances between the ATP binding site and phosphorylation site revealed the existence of two ATP binding sites in the open conformation; the first one close to Phe475 in the N-domain, the other one close to Asp369 in the P-domain. However, binding of Mg2+•ATP to any of these sites in the “open conformation” may not lead to phosphorylation of Asp369. Additional conformations of the cytoplasmic loop were found wobbling between “open conformation”  “semi-open conformation  “closed conformation” in the absence of 2Mg2+•ATP. The cytoplasmic loop’s conformational change to the “semi-open conformation”—characterized by a hydrogen bond between Arg543 and Asp611—triggers by binding of 2Mg2+•ATP to a single ATP site and conversion to the “closed conformation” the phosphorylation of Asp369 in the P-domain, and hence the start of Na+/K+-activated ATP hydrolysis.

  2. Computer modelling reveals new conformers of the ATP binding loop of Na+/K+-ATPase involved in the transphosphorylation process of the sodium pump

    Science.gov (United States)

    Tejral, Gracian; Sopko, Bruno; Necas, Alois; Schoner, Wilhelm

    2017-01-01

    Hydrolysis of ATP by Na+/K+-ATPase, a P-Type ATPase, catalyzing active Na+ and K+ transport through cellular membranes leads transiently to a phosphorylation of its catalytical α-subunit. Surprisingly, three-dimensional molecular structure analysis of P-type ATPases reveals that binding of ATP to the N-domain connected by a hinge to the P-domain is much too far away from the Asp369 to allow the transfer of ATP’s terminal phosphate to its aspartyl-phosphorylation site. In order to get information for how the transfer of the γ-phosphate group of ATP to the Asp369 is achieved, analogous molecular modeling of the M4–M5 loop of ATPase was performed using the crystal data of Na+/K+-ATPase of different species. Analogous molecular modeling of the cytoplasmic loop between Thr338 and Ile760 of the α2-subunit of Na+/K+-ATPase and the analysis of distances between the ATP binding site and phosphorylation site revealed the existence of two ATP binding sites in the open conformation; the first one close to Phe475 in the N-domain, the other one close to Asp369 in the P-domain. However, binding of Mg2+•ATP to any of these sites in the “open conformation” may not lead to phosphorylation of Asp369. Additional conformations of the cytoplasmic loop were found wobbling between “open conformation”  “semi-open conformation  “closed conformation” in the absence of 2Mg2+•ATP. The cytoplasmic loop’s conformational change to the “semi-open conformation”—characterized by a hydrogen bond between Arg543 and Asp611—triggers by binding of 2Mg2+•ATP to a single ATP site and conversion to the “closed conformation” the phosphorylation of Asp369 in the P-domain, and hence the start of Na+/K+-activated ATP hydrolysis. PMID:28316890

  3. ATP regulation of type-1 inositol 1,4,5-trisphosphate receptor activity does not require walker A-type ATP-binding motifs.

    Science.gov (United States)

    Betzenhauser, Matthew J; Wagner, Larry E; Park, Hyung Seo; Yule, David I

    2009-06-12

    ATP is known to increase the activity of the type-1 inositol 1,4,5-trisphosphate receptor (InsP3R1). This effect is attributed to the binding of ATP to glycine rich Walker A-type motifs present in the regulatory domain of the receptor. Only two such motifs are present in neuronal S2+ splice variant of InsP3R1 and are designated the ATPA and ATPB sites. The ATPA site is unique to InsP3R1, and the ATPB site is conserved among all three InsP3R isoforms. Despite the fact that both the ATPA and ATPB sites are known to bind ATP, the relative contribution of these two sites to the enhancing effects of ATP on InsP3R1 function is not known. We report here a mutational analysis of the ATPA and ATPB sites and conclude neither of these sites is required for ATP modulation of InsP3R1. ATP augmented InsP3-induced Ca2+ release from permeabilized cells expressing wild type and ATP-binding site-deficient InsP3R1. Similarly, ATP increased the single channel open probability of the mutated InsP3R1 to the same extent as wild type. ATP likely exerts its effects on InsP3R1 channel function via a novel and as yet unidentified mechanism.

  4. Two different point mutations in ABL gene ATP-binding domain conferring Primary Imatinib resistance in a Chronic Myeloid Leukemia (CML patient: A case report

    Directory of Open Access Journals (Sweden)

    Iqbal Zafar

    2004-01-01

    Full Text Available Imatinib (Gleevec is the effective therapy for BCR-ABL positive CML patients. Point mutations have been detected in ATP-binding domain of ABL gene which disturbs the binding of Gleevec to this target leading to resistance. Detection of mutations is helpful in clinical management of imatinib resistance. We established a very sensitive (ASO PCR to detect mutations in an imatinib-resistant CML patient. Mutations C944T and T1052C were detected which cause complete partial imatinib resistance, respectively. This is the first report of multiple point mutations conferring primary imatinib resistance in same patient at the same time. Understanding the biological reasons of primary imatinib resistance is one of the emerging issues of pharmacogenomics and will be helpful in understanding primary resistance of molecularly-targeted cancer therapies. It will also be of great utilization in clinical management of imatinib resistance. Moreover, this ASO-PCR assay is very effective in detecting mutations related to imatinib resistance.

  5. ATP binding by the P-loop NTPase OsYchF1 (an unconventional G protein) contributes to biotic but not abiotic stress responses.

    Science.gov (United States)

    Cheung, Ming-Yan; Li, Xiaorong; Miao, Rui; Fong, Yu-Hang; Li, Kwan-Pok; Yung, Yuk-Lin; Yu, Mei-Hui; Wong, Kam-Bo; Chen, Zhongzhou; Lam, Hon-Ming

    2016-03-01

    G proteins are involved in almost all aspects of the cellular regulatory pathways through their ability to bind and hydrolyze GTP. The YchF subfamily, interestingly, possesses the unique ability to bind both ATP and GTP, and is possibly an ancestral form of G proteins based on phylogenetic studies and is present in all kingdoms of life. However, the biological significance of such a relaxed ligand specificity has long eluded researchers. Here, we have elucidated the different conformational changes caused by the binding of a YchF homolog in rice (OsYchF1) to ATP versus GTP by X-ray crystallography. Furthermore, by comparing the 3D relationships of the ligand position and the various amino acid residues at the binding sites in the crystal structures of the apo-bound and ligand-bound versions, a mechanism for the protein's ability to bind both ligands is revealed. Mutation of the noncanonical G4 motif of the OsYchF1 to the canonical sequence for GTP specificity precludes the binding/hydrolysis of ATP and prevents OsYchF1 from functioning as a negative regulator of plant-defense responses, while retaining its ability to bind/hydrolyze GTP and its function as a negative regulator of abiotic stress responses, demonstrating the specific role of ATP-binding/hydrolysis in disease resistance. This discovery will have a significant impact on our understanding of the structure-function relationships of the YchF subfamily of G proteins in all kingdoms of life.

  6. Solution structure of the 45-residue MgATP-binding peptide of adenylate kinase as examined by 2-D NMR, FTIR, and CD spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fry, D.C.; Byler, D.M.; Susi, H.; Brown, M.; Kuby, S.A.; Mildvan A.S.

    1988-05-17

    The structure of a synthetic peptide corresponding to residues 1-45 of rabbit muscle adenylate kinase has been studied in aqueous solution by two-dimensional NMR, FTIR, and CD spectroscopy. This peptide, which binds MgATP and is believed to represent most of the MgATP-binding site of the enzyme, appears to maintain a conformation similar to that of residues 1-45 in the X-ray structure of intact porcine adenylate kinase, with 42% of the residues of the peptide showing NOEs indicative of phi and psi angles corresponding to those found in the protein. The NMR studies suggest that the peptide is composed of two helical regions of residues 4-7 and 23-29, and three stretches of ..beta..-strand at residues 8-15, 30-32, and 35-40, yielding an overall secondary structure consisting of 24% ..cap alpha..-helix, 38% ..beta..-structure, and 38% aperiodic. Although the resolution-enhanced amide I band of the peptide FTIR spectrum is broad and rather featureless, possible due to disorder, it can be fit by using methods developed on well-characterized globular proteins. The CD spectrum is best fit by assuming the presence of at most 13% ..cap alpha..-helix in the peptide, 24 +/- 2% ..beta..-structure, and 66 +/- 4% aperiodic. The inability of the high-frequency FTIR and CD methods to detect helices in the amount found by NMR may result from the short helical lengths as well as from static and dynamic disorder in the peptide. Upon binding of MgATP, numerous conformation changes in the backbone of the peptide are detected by NMR, with smaller alterations in the overall secondary structure as assess by CD.

  7. Solution structure of the 45-residue ATP-binding peptide of adenylate kinase as determined by 2-D NMR, FTIR, and CD spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fry, D.C.; Byler, D.M.; Susi, H.; Brown, E.M.; Kuby, S.A.; Mildyan, A.S.

    1986-05-01

    In the X-ray structure of adenylate kinase residues 1-45 exist as 47% ..cap alpha..-helix, 29% ..beta..-structure (strands and turns) and 24% coil. The solution structure of a synthetic peptide corresponding to residues 1-45, which constitutes the MgATP binding site was studied by 3 independent spectroscopic methods. Globularity of the peptide was shown by its broad NMR resonances which narrow upon denaturation, and by its ability to bind MgATP with similar affinity and conformation as the intact enzyme does. COSY and NOESY NMR methods at 250 and 500 MHz reveal proximities among NH, C..cap alpha.., and C..beta.. protons indicative of >20% ..cap alpha..-helix, and >20% ..beta..-structure. Correlation of regions of secondary structure with the primary sequence by 2D NMR indicates at least one ..cap alpha..-helix (res. 23 to 29) and two ..beta..-strands (res. 12 to 15 and 34 to 38). The broad amide I band in the deconvoluted FTIR spectrum could be fit as the sum of 4 peaks due to specific secondary structures, yielding less than or equal to=45% ..cap alpha..-helix, less than or equal to=40% ..beta..-structure and greater than or equal to=15% coil. The CD spectrum, from 185-250 nm, interpreted with a 3-parameter basis set, yielded 20 +/- 5% ..cap alpha..=helix, and less than or equal to=20% ..beta..-structure. The solution structure of peptide 1-45 thus approximates that of residues 1-45 in the crystal.

  8. ABC Technology Development Program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-10-14

    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.

  9. Whatever happened to cassette-dosing pharmacokinetics?

    Science.gov (United States)

    Manitpisitkul, Prasarn; White, Ronald E

    2004-08-01

    Cassette dosing is a procedure that is used for rapidly assessing the pharmacokinetics of a series of discovery drug candidates by dosing a mixture of compounds rather than a single compound. Cassette dosing has advantages and disadvantages associated with its use, which leads to controversy about how and if it should be used. To assess the current practices of the pharmaceutical industry regarding cassette dosing, a survey of several pharmaceutical companies was conducted. Analysis of the survey revealed that opinion on this subject is divided within the pharmaceutical industry. In addition, it was determined that approximately only a half of those companies that perform in vivo pharmacokinetic screening use cassette dosing for this purpose.

  10. Solution structure of the 45-residue MgATP-binding peptide of adenylate kinase as examined by 2-D NMR, FTIR, and CD spectroscopy.

    Science.gov (United States)

    Fry, D C; Byler, D M; Susi, H; Brown, E M; Kuby, S A; Mildvan, A S

    1988-05-17

    The structure of a synthetic peptide corresponding to residues 1-45 of rabbit muscle adenylate kinase has been studied in aqueous solution by two-dimensional NMR, FTIR, and CD spectroscopy. This peptide, which binds MgATP and is believed to represent most of the MgATP-binding site of the enzyme [Fry, D.C., Kuby, S.A., & Mildvan, A.S. (1985) Biochemistry 24, 4680-4694], appears to maintain a conformation similar to that of residues 1-45 in the X-ray structure of intact porcine adenylate kinase [Sachsenheimer, W., & Schulz, G.E. (1977) J. Mol. Biol. 114, 23-26], with 42% of the residues of the peptide showing NOEs indicative of phi and psi angles corresponding to those found in the protein. The NMR studies suggest that the peptide is composed of two helical regions of residues 4-7 and 23-29, and three stretches of beta-strand at residues 8-15, 30-32, and 35-40, yielding an overall secondary structure consisting of 24% alpha-helix, 38% beta-structure, and 38% aperiodic. Although the resolution-enhanced amide I band of the peptide FTIR spectrum is broad and rather featureless, possibly due to disorder, it can be fit by using methods developed on well-characterized globular proteins. On this basis, the peptide consists of 35 +/- 10% beta-structure, 60 +/- 12% turns and aperiodic structure, and not more than 10% alpha-helix. The CD spectrum is best fit by assuming the presence of at most 13% alpha-helix in the peptide, 24 +/- 2% beta-structure, and 66 +/- 4% aperiodic. The inability of the high-frequency FTIR and CD methods to detect helices in the amount found by NMR may result from the short helical lengths as well as from static and dynamic disorder in the peptide. Upon binding of MgATP, numerous conformational changes in the backbone of the peptide are detected by NMR, with smaller alterations in the overall secondary structure as assessed by CD. Detailed assignments of resonances in the peptide spectrum and intermolecular NOEs between protons of bound MgATP and

  11. A sensor for intracellular ionic strength

    NARCIS (Netherlands)

    Biemans-Oldehinkel, Esther; Mahmood, Nik A.B.N.; Poolman, Bert

    2006-01-01

    Cystathionine-β-synthase (CBS) domains are found in >4,000 proteins in species from all kingdoms of life, yet their functions are largely unknown. Tandem CBS domains are associated with membrane transport proteins, most notably members of the ATP-binding cassette (ABC) superfamily; voltage-gated chl

  12. sphingosine-1-phosphate transport and its role in immunology

    NARCIS (Netherlands)

    Reitsema, V.; Bouma, Hjalmar; Kok, Jan

    2014-01-01

    Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite with many important functions in cellular and systemic physiology, including the immune system. As it cannot traverse the membrane, it is exported from cells by transporters. Several members of the ATP-binding cassette (ABC) transporter fami

  13. PfMDR2 and PfMDR5 are dispensable for Plasmodium falciparum asexual parasite multiplication but change in vitro susceptibility to anti-malarial drugs

    NARCIS (Netherlands)

    Velden, M. van der; Rijpma, S.R.; Russel, F.G.M.; Sauerwein, R.W.; Koenderink, J.B.

    2015-01-01

    BACKGROUND: Membrane-associated ATP binding cassette (ABC) transport proteins hydrolyze ATP in order to translocate a broad spectrum of substrates, from single ions to macromolecules across membranes. In humans, members from this transport family have been linked to drug resistance phenotypes, e.g.,

  14. Pharmacological functions of multidrug transporters: studies employing combination transporter knockout mice

    NARCIS (Netherlands)

    Lagas, J.S.

    2009-01-01

    ATP-binding cassette (ABC) multidrug transporters are drug efflux pumps located in the plasma membrane that utilize the energy of ATP hydrolysis to extrude a wide spectrum of endogenous and exogenous compounds from cells, including numerous (anticancer) drugs and/or their metabolites. The studies de

  15. AcEST: DK962825 [AcEST

    Lifescience Database Archive (English)

    Full Text Available ly A member 1... 34 0.43 sp|Q8WWZ4|ABCAA_HUMAN ATP-binding cassette sub-family A ...ctase chain 5 OS=C... 31 3.6 sp|Q54R52|ABCAA_DICDI ABC transporter A family member 10 OS=Dict... 31 3.7 sp|P

  16. Transcriptional control of hepatocanalicular transporter gene expression

    NARCIS (Netherlands)

    Muller, M

    2000-01-01

    Transport processes for larger organic solutes at the canalicular membrane are mainly driven by members of the superfamily of ATP-binding cassette (ABC) transporters. The funct ions of these transporters range from bile component secretion to xenobiotica and phase II-conjugate export. The transcript

  17. the role of the actin cytoskeleton and lipid rafts in the localization and function of the ABCC1 transporter

    NARCIS (Netherlands)

    Kok, Jan; Klappe, Katharina; Hummel, Ina

    2014-01-01

    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 A

  18. Inhibition of multixenobiotic resistance transporters (MXR) by silver nanoparticles and ions in vitro and in Daphnia magna

    NARCIS (Netherlands)

    Georgantzopoulou, Anastasia; Cambier, Sébastien; Serchi, Tommaso; Kruszewski, Marcin; Balachandran, Yekkuni L.; Grysan, Patrick; Audinot, Jean Nicolas; Ziebel, Johanna; Guignard, Cédric; Gutleb, Arno C.; Murk, Tinka

    2016-01-01

    The P-glycoprotein (P-gp, ABCB1) and multidrug resistance associated protein 1 (MRP1), important members of the ABC (ATP-binding cassette) transporters, protect cells and organisms via efflux of xenobiotics and are responsible for the phenomenon of multidrug or multixenobiotic resistance (MXR). I

  19. Drug Transporters in the Intestine

    DEFF Research Database (Denmark)

    Steffansen, Bente

    2016-01-01

    The enterocyte monolayer in the intestinal membrane impacts on the bioavailability (BA) of many orally administered active pharmaceutical ingredients (APIs). The monolayer expresses a multitude of membrane transporters belonging to the solute carrier (SLC) and ATP-binding cassette (ABC) families ...

  20. The Liver X Receptor (LXR) and its Target Gene ABCA1 are Regulated Upon Low Oxygen in Human Trophoblast Cells : A Reason for Alterations in Preeclampsia?

    NARCIS (Netherlands)

    Plosch, T.; Gellhaus, A.; van Straten, E. M. E.; Wolf, N.; Huijkman, N. C. A.; Schmidt, M.; Dunk, C. E.; Kuipers, F.; Winterhager, E.

    2010-01-01

    Objectives: The Liver X receptors (LXR) alpha and beta and their target genes such as the ATP-binding cassette (ABC) transporters have been shown to be crucially involved in the regulation of cellular cholesterol homeostasis. The aim of this study was to characterize the role of LXR alpha/beta in th

  1. Gclust Server: 76160 [Gclust Server

    Lifescience Database Archive (English)

    Full Text Available 76160 SCE_YLR188W=MDL1 Cluster Sequences Related Sequences(340) 695 Half-type ATP-b...es(340) Sequence length 695 Representative annotation Half-type ATP-binding cassette (ABC) transporter of th

  2. ABCs in College English Education

    Institute of Scientific and Technical Information of China (English)

    李利文

    2011-01-01

    As is known to us all, human beings are always brought under control by such many things as the hormone in our body, the mood produced in our brain and the external world, which leads us to a topic of how to create an atmosphere for the undergraduates to fit well in with the college English education. In our teaching management, the ABCs about college English education works as an assistant. Here, ABCs about college English education refer to some fundamental skills with regard to the undergraduates English education. The ABCs, which always encourage students' involvement, would work effectively if teachers understand them well.

  3. 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)

  4. 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.

  5. Not as Simple as ABC

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Agricultural Bank of China finds it tough as it moves toward marketization The Agricultural Bank of China (ABC) is sailing through rough seas as it weathers the storm of problems uncovered during its current stage of reform.With non-performing assets making up nearly 97 percent of the total of China’ s four large state-owned commercial banks, alarm bells are going off in ABC halls of power.

  6. An asymmetric post-hydrolysis state of the ABC transporter ATPase dimer.

    Directory of Open Access Journals (Sweden)

    Anthony M George

    Full Text Available ABC transporters are a superfamily of enzyme pumps that hydrolyse ATP in exchange for translocation of substrates across cellular membranes. Architecturally, ABC transporters are a dimer of transmembrane domains coupled to a dimer of nucleotide binding domains (NBDs: the NBD dimer contains two ATP-binding sites at the intersubunit interface. A current controversy is whether the protomers of the NBD dimer separate during ATP hydrolysis cycling, or remain in constant contact. In order to investigate the ABC ATPase catalytic mechanism, MD simulations using the recent structure of the ADP+Pi-bound MJ0796 isolated NBD dimer were performed. In three independent simulations of the ADP+Pi/apo state, comprising a total of >0.5 µs, significant opening of the apo (empty active site was observed; occurring by way of intrasubunit rotations between the core and helical subdomains within both NBD monomers. In contrast, in three equivalent simulations of the ATP/apo state, the NBD dimer remained close to the crystal structure, and no opening of either active site occurred. The results thus showed allosteric coupling between the active sites, mediated by intrasubunit conformational changes. Opening of the apo site is exquisitely tuned to the nature of the ligand, and thus to the stage of the reaction cycle, in the opposite site. In addition to this, in also showing how one active site can open, sufficient to bind nucleotide, while the opposite site remains occluded and bound to the hydrolysis products ADP+Pi, the results are consistent with a Constant Contact Model. Conversely, they show how there may be no requirement for the NBD protomers to separate to complete the catalytic cycle.

  7. The H-loop in the Second Nucleotide-binding Domain of the Cystic Fibrosis Transmembrane Conductance Regulator is Required for Efficient Chloride Channel Closing

    OpenAIRE

    Kloch, Monika; Milewski, Michał; Nurowska, Ewa; Dworakowska, Beata; Cutting, Garry R.; Dołowy, Krzysztof

    2010-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a cAMP-activated chloride channel. The recent model of CFTR gating predicts that the ATP binding to both nucleotide-binding domains (NBD1 and NBD2) of CFTR is required for the opening of the channel, while the ATP hydrolysis at NBD2 induces subsequent channel closing. In most ABC proteins, efficient hydrolysis of ATP requires the presence of the invariant histidine res...

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

    Science.gov (United States)

    Ohtsu, Iwao; Kawano, Yusuke; Suzuki, Marina; Morigasaki, Susumu; Saiki, Kyohei; Yamazaki, Shunsuke; Nonaka, Gen; Takagi, Hiroshi

    2015-01-01

    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.

  9. 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.

  10. Reference: 698 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available r ATP-binding cassette (ABC) transporters in root exudation of phytochemicals, we identified 25 ABC transpor...ter for in-depth molecular and biochemical analyses. We compared the exuded root phytochemical profiles of t...hese seven ABC transporter mutants to those of the wild type. There were three nonpolar phytochemical... one ABC transporter can be involved in the secretion of a given phytochemical an...ype. We conclude that the release of phytochemicals by roots is partially controlled by ABC transporters. Al

  11. Multidrug resistance associated proteins in multidrug resistance

    OpenAIRE

    Sodani, Kamlesh; Patel, Atish; Kathawala, Rishil J.; Chen, Zhe-Sheng

    2012-01-01

    Multidrug resistance proteins (MRPs) are members of the C family of a group of proteins named ATP-binding cassette (ABC) transporters. These ABC transporters together form the largest branch of proteins within the human body. The MRP family comprises of 13 members, of which MRP1 to MRP9 are the major transporters indicated to cause multidrug resistance in tumor cells by extruding anticancer drugs out of the cell. They are mainly lipophilic anionic transporters and are reported to transport fr...

  12. Identification of a novel post-hydrolytic state in CFTR gating

    OpenAIRE

    Jih, Kang-Yang; Sohma, Yoshiro; Li, Min; Hwang, Tzyh-Chang

    2012-01-01

    Adenosine triphosphate (ATP)-binding cassette (ABC) transporters, ubiquitous proteins found in all kingdoms of life, catalyze substrates translocation across biological membranes using the free energy of ATP hydrolysis. Cystic fibrosis transmembrane conductance regulator (CFTR) is a unique member of this superfamily in that it functions as an ATP-gated chloride channel. Despite difference in function, recent studies suggest that the CFTR chloride channel and the exporter members of the ABC pr...

  13. Localizing a gate in CFTR

    OpenAIRE

    Gao, Xiaolong; Hwang, Tzyh-Chang

    2015-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR), albeit a bona fide member of the ATP-binding cassette (ABC) transporter superfamily, is an ATP-gated chloride channel. However, phylogenetic analysis has led to a popular conjecture that CFTR evolves from a primordial ABC exporter by simply degenerating the cytoplasmic gate. This degraded transporter hypothesis predicts that CFTR’s gate is located at the external end of the substrate translocation pathway as the one documented in the...

  14. WBC27, an Adenosine Tri-phosphate-binding Cassette Protein, Controls Pollen Wall Formation and Patterning in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ying Dou; Ke-Zhen Yang; Yi Zhang; Wei Wang; Xiao-Lei Liu; Li-Qun Chen; Xue-Qin Zhang; De Ye

    2011-01-01

    In flowering plants, the exine components are derived from tapetum. Despite its importance to sexual plant reproduction, little is known about the translocation of exine materials from tapetum to developing microspores. Here we report functional characterization of the arabidopsis WBC27 gene. WBC27 encodes an adenosine tri-phosphate binding cassette (ABC) transporter and is expressed preferentially in tapetum. Mutation of WBC27 disrupted the exine formation. The wbc27 mutant microspores began to degenerate once released from tetrads and most of the microspores collapsed at the uninucleate stage. Only a small number of wbc27-1 microspores could develop into tricellular pollen grains. These survival pollen grains lacked exine and germinated in the anther before anthesis. All of these results suggest that the ABC transporter, WBC27 plays important roles in the formation of arabidopsis exine, possibly by translocation of lipidic precursors of sporopollenin from tapetum to developing microspores.

  15. 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

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

  16. 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.”

  17. The ABCs of Student Engagement

    Science.gov (United States)

    Parsons, Seth A.; Nuland, Leila Richey; Parsons, Allison Ward

    2014-01-01

    Student engagement is an important consideration for teachers and administrators because it is explicitly associated with achievement. What the authors call the ABC's of engagement they outline as: Affective engagement, Behavioral engagement, and Cognitive engagement. They also present "Three Things Every Teacher Needs to Know about…

  18. Wireless technology for ABC Assessment

    DEFF Research Database (Denmark)

    Kristensen, Margit; Kyng, Morten; Christensen, Erika Frischknecht;

      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 ...

  19. Concept design of the cassette toroidal mover

    Energy Technology Data Exchange (ETDEWEB)

    Maekinen, H., E-mail: harri.makinen@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1300, FI-33101 Tampere (Finland); Jaervenpaeae, J. [VTT Technical Research Centre of Finland, P.O. Box 1300, FI-33101 Tampere (Finland); Valkama, P.; Vaeyrynen, J.; Amjad, F. [Tampere University of Technology, Korkeakoulunkatu 6, 33720 Tampere (Finland); Siuko, M. [VTT Technical Research Centre of Finland, P.O. Box 1300, FI-33101 Tampere (Finland); Mattila, J. [Tampere University of Technology, Korkeakoulunkatu 6, 33720 Tampere (Finland); Semeraro, L.; Esque, S. [Fusion for Energy, Torres Diagonal Litoral B3, Josep Pla 2, 08019 Barcelona (Spain)

    2011-10-15

    A full scale physical development and test facility, Divertor Test Platform 2 (DTP2), has been established in Finland for the purpose of demonstrating and developing the remote handling (RH) equipment designs for ITER using prototypes and virtual models. The major objective of the DTP2 environment is to verify and develop ITER divertor RH devices and operations. In practice this means various test trials and measurements of performance characteristics. This paper describes the design process of the Cassette Toroidal Mover (CTM). The main purpose of this design task was the development of the CTM concept. The goal of the design process was to achieve compatibility between CTM and the latest ITER divertor design. The design process was based on using a variety of tools, i.e. Catia V5, Delmia, Ansys, Mathcad and project management tools. Applicable European Standards were applied to the concept design. CTM is the cassette transporter, which carries divertor cassettes on the toroidal rails inside the ITER Vacuum Vessel (VV) during the divertor maintenance. The operation environment differs from a common industrial environment. Radiation level is 100 Gy/h. The temperature during RH operations can be 50 {sup o}C. Clearances are less than 20 mm and the loads carried weigh 9000 kg. These conditions require special solutions during the product development process. The design process consisted of defining and developing of the CTM operational sequence. This sequence includes the procedure of how the CTM - with it is onboard manipulator - prepares for and handles the divertor cassettes during RH operations. RH operations are essential part when defining CTM functions. High reliability is required in order to carry out RH tasks successfully. The recoverability of CTM is also an important design criteria. This paper describes the design process and the structure of the CTM concept.

  20. CryoEM and Molecular Dynamics of the Circadian KaiB-KaiC Complex Indicates That KaiB Monomers Interact with KaiC and Block ATP Binding Clefts

    Energy Technology Data Exchange (ETDEWEB)

    Villarreal, Seth A.; Pattanayek, Rekha; Williams, Dewight R.; Mori, Tetsuya; Qin, Ximing; Johnson, Carl H.; Egli, Martin; Stewart, Phoebe L. [Case Western; (Vanderbilt); (Vanderbilt-MED)

    2014-10-02

    The circadian control of cellular processes in cyanobacteria is regulated by a posttranslational oscillator formed by three Kai proteins. During the oscillator cycle, KaiA serves to promote autophosphorylation of KaiC while KaiB counteracts this effect. Here, we present a crystallographic structure of the wild-type Synechococcus elongatus KaiB and a cryo-electron microscopy (cryoEM) structure of a KaiBC complex. The crystal structure shows the expected dimer core structure and significant conformational variations of the KaiB C-terminal region, which is functionally important in maintaining rhythmicity. The KaiBC sample was formed with a C-terminally truncated form of KaiC, KaiC-Δ489, which is persistently phosphorylated. The KaiB–KaiC-Δ489 structure reveals that the KaiC hexamer can bind six monomers of KaiB, which form a continuous ring of density in the KaiBC complex. We performed cryoEM-guided molecular dynamics flexible fitting simulations with crystal structures of KaiB and KaiC to probe the KaiBC protein–protein interface. This analysis indicated a favorable binding mode for the KaiB monomer on the CII end of KaiC, involving two adjacent KaiC subunits and spanning an ATP binding cleft. A KaiC mutation, R468C, which has been shown to affect the affinity of KaiB for KaiC and lengthen the period in a bioluminescence rhythm assay, is found within the middle of the predicted KaiBC interface. The proposed KaiB binding mode blocks access to the ATP binding cleft in the CII ring of KaiC, which provides insight into how KaiB might influence the phosphorylation status of KaiC.

  1. Phosphorylation at Ser²⁶ in the ATP-binding site of Ca²⁺/calmodulin-dependent kinase II as a mechanism for switching off the kinase activity.

    Science.gov (United States)

    Yilmaz, Mehtap; Gangopadhyay, Samudra S; Leavis, Paul; Grabarek, Zenon; Morgan, Kathleen G

    2013-02-07

    CaMKII (Ca²⁺/calmodulin-dependent kinase II) is a serine/threonine phosphotransferase that is capable of long-term retention of activity due to autophosphorylation at a specific threonine residue within each subunit of its oligomeric structure. The γ isoform of CaMKII is a significant regulator of vascular contractility. Here, we show that phosphorylation of CaMKII γ at Ser²⁶, a residue located within the ATP-binding site, terminates the sustained activity of the enzyme. To test the physiological importance of phosphorylation at Ser²⁶, we generated a phosphospecific Ser²⁶ antibody and demonstrated an increase in Ser²⁶ phosphorylation upon depolarization and contraction of blood vessels. To determine if the phosphorylation of Ser²⁶ affects the kinase activity, we mutated Ser²⁶ to alanine or aspartic acid. The S26D mutation mimicking the phosphorylated state of CaMKII causes a dramatic decrease in Thr²⁸⁷ autophosphorylation levels and greatly reduces the catalytic activity towards an exogenous substrate (autocamtide-3), whereas the S26A mutation has no effect. These data combined with molecular modelling indicate that a negative charge at Ser²⁶ of CaMKII γ inhibits the catalytic activity of the enzyme towards its autophosphorylation site at Thr²⁸⁷ most probably by blocking ATP binding. We propose that Ser²⁶ phosphorylation constitutes an important mechanism for switching off CaMKII activity.

  2. Sustaining an Effective ABC-ABM System

    Directory of Open Access Journals (Sweden)

    Gary COKINS

    2011-02-01

    Full Text Available The purpose of this paper is to describe the Activity- Based Costing (ABC and Activity-Based Management (ABM system and techniques to sustain them as a permanent and repeatable production reporting system, not just for one-off analysis. A comparison is made between ABC/ABM modeling software that extracts source data and business systems that include ABC/ABM modeling features. There are presented the stages of updating, running and rerunning the ABC/ABM system. The resulting information calculated and provided by the ABC/ABM system are analyzed and interpreted in terms of a multidimensional data analysis. The article ends with the authors' conclusions about the benefits of continued operation of sustaining the ABC/ABM system.

  3. A Cassette Based System for Hydrogen Storage and Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Britton Wayne E.

    2006-11-29

    A hydrogen storage system is described and evaluated. This is based upon a cassette, that is a container for managing hydrogen storage materials. The container is designed to be safe, modular, adaptable to different chemistries, inexpensive, and transportable. A second module receives the cassette and provides the necessary infrastructure to deliver hydrogen from the cassette according to enduser requirements. The modular concept has a number of advantages over approaches that are all in one stand alone systems. The advantages of a cassette based system are discussed, along with results from model and laboratory testing.

  4. 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

    Efflux transporters of the ATP-binding cassette superfamily including breast cancer resistance protein (Bcrp/Abcg2), P-glycoprotein (P-gp/Abcb1) and multidrug resistance-associated proteins (Mrp's/Abcc's) are expressed in the blood-brain barrier (BBB). The aim of this study was to investigate......, zosuquidar, reversan and MK 571 alone or in combinations. Digoxin was mainly transported via P-gp, estrone-3-sulphate via Bcrp and Mrp's and etoposide via P-gp and Mrp's. The expression of P-gp, Bcrp and Mrp-1 was confirmed using immunocytochemistry. The findings indicate that P-gp, Bcrp and at least one...... isoform of Mrp are functionally expressed in our bovine/rat co-culture model and that the model is suitable for investigations of small molecule transport....

  5. ABC model and floral evolution

    Institute of Scientific and Technical Information of China (English)

    LI Guisheng; MENG Zheng; KONG Hongzhi; CHEN Zhiduan; LU Anming

    2003-01-01

    The paper introduces the classical ABC model of floral development and thereafter ABCD, ABCDE and quartet models, and presents achievements in the studies on floral evolution such as the improved understanding on the relationship of reproductive organs between gnetophytes and angiosperms, new results in perianth evolution and identified homology of floral organs between dicots and monocots. The evo-devo studies on plant taxa at different evolutionary levels are useful to better understanding the homology of floral organs, and to clarifying the mysteries of the origin and subsequent diversification of flowers.

  6. Therapeutic potential of inhibiting ABCE1 and eRF3 genes via siRNA strategy using chitosan nanoparticles in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Cengiz, Bagdat Burcu; Asik, Mehmet Dogan [Hacettepe University, Nanotechnology and Nanomedicine Division (Turkey); Kara, Goknur [Hacettepe University, Biochemistry Division, Chemistry Department (Turkey); Turk, Mustafa [Kirikkale University, Bioengineering Department (Turkey); Denkbas, Emir Baki, E-mail: denkbas@hacettepe.edu.tr [Hacettepe University, Biochemistry Division, Chemistry Department (Turkey)

    2015-04-15

    In recent years, targeted cancer therapy strategies have begun to take the place of the conventional treatments. Inhibition of the specific genes, involved in cancer progress, via small interfering RNA (siRNA) has become one of the promising therapeutic approaches for cancer therapy. However, due to rapid nuclease degradation and poor cellular uptake of siRNA, a suitable carrier for siRNA penetration inside the cells is required. We used chitosan nanoparticles (CS-NPs) to efficiently deliver ATP-binding casette E1 (ABCE1) and eukaryotic release factor 3 (eRF3)-targeting siRNAs, individually and together, to reduce the proliferation and induce the apoptosis of breast cancer cells. The CS-NPs were generated by ionic gelation method using tripolyphosphate (TPP) as a crosslinker. Nanoparticles (NPs) were obtained with diameters ranging between 110 and 230 nm and the zeta potential of approximately 27 mV optimizing the solution pH to 4.5 and CS/TPP mass ratio to 3:1. Loading efficiencies of 98.69 % ± 0.051 and 98.83 % ± 0.047 were achieved when ABCE1 siRNA and eRF3 siRNA were entrapped into the NPs, respectively. Cell proliferation assay demonstrated that siRNA-loaded CS-NPs were more effective on cancer cells when compared to siRNAs without CS-NPs. Parallel results were also obtained by apoptosis/necrosis, double-staining analysis. Within our study, the potency of ABCE1 and eRF3 siRNAs were shown for the first time with this kind of polymeric delivery system. The results also indicated that ABCE1 and eRF3, important molecules in protein synthesis, could serve as effective targets to inhibit the cancer cells.

  7. Metabolic Interactions of Purine Derivatives with Human ABC Transporter ABCG2: Genetic Testing to Assess Gout Risk

    Directory of Open Access Journals (Sweden)

    Kiyoko Kaneko

    2013-11-01

    Full Text Available In mammals, excess purine nucleosides are removed from the body by breakdown in the liver and excretion from the kidneys. Uric acid is the end product of purine metabolism in humans. Two-thirds of uric acid in the human body is normally excreted through the kidney, whereas one-third undergoes uricolysis (decomposition of uric acid in the gut. Elevated serum uric acid levels result in gout and could be a risk factor for cardiovascular disease and diabetes. Recent studies have shown that human ATP-binding cassette transporter ABCG2 plays a role of renal excretion of uric acid. Two non-synonymous single nucleotide polymorphisms (SNPs, i.e., 421C>A (major and 376C>T (minor, in the ABCG2 gene result in impaired transport activity, owing to ubiquitination-mediated proteosomal degradation and truncation of ABCG2, respectively. These genetic polymorphisms are associated with hyperuricemia and gout. Allele frequencies of those SNPs are significantly higher in Asian populations than they are in African and Caucasian populations. A rapid and isothermal genotyping method has been developed to detect the SNP 421C>A, where one drop of peripheral blood is sufficient for the detection. Development of simple genotyping methods would serve to improve prevention and early therapeutic intervention for high-risk individuals in personalized healthcare.

  8. Ectoine-induced proteins in Sinorhizobium meliloti include an Ectoine ABC-type transporter involved in osmoprotection and ectoine catabolism.

    Science.gov (United States)

    Jebbar, Mohamed; Sohn-Bösser, Linda; Bremer, Erhard; Bernard, Théophile; Blanco, Carlos

    2005-02-01

    To understand the mechanisms of ectoine-induced osmoprotection in Sinorhizobium meliloti, a proteomic examination of S. meliloti cells grown in minimal medium supplemented with ectoine was undertaken. This revealed the induction of 10 proteins. The protein products of eight genes were identified by using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. Five of these genes, with four other genes whose products were not detected on two-dimensional gels, belong to the same gene cluster, which is localized on the pSymB megaplasmid. Four of the nine genes encode the characteristic components of an ATP-binding cassette transporter that was named ehu, for ectoine/hydroxyectoine uptake. This transporter was encoded by four genes (ehuA, ehuB, ehuC, and ehuD) that formed an operon with another gene cluster that contains five genes, named eutABCDE for ectoine utilization. On the basis of sequence homologies, eutABCDE encode enzymes with putative and hypothetical functions in ectoine catabolism. Analysis of the properties of ehuA and eutA mutants suggests that S. meliloti possesses at least one additional ectoine catabolic pathway as well as a lower-affinity transport system for ectoine and hydroxyectoine. The expression of ehuB, as determined by measurements of UidA activity, was shown to be induced by ectoine and hydroxyectoine but not by glycine betaine or by high osmolality.

  9. 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.

  10. Human small cell lung cancer NYH cells selected for resistance to the bisdioxopiperazine topoisomerase II catalytic inhibitor ICRF-187 demonstrate a functional R162Q mutation in the Walker A consensus ATP binding domain of the alpha isoform

    DEFF Research Database (Denmark)

    Wessel, I; Jensen, L H; Jensen, P B;

    1999-01-01

    -AMSA), which act by stabilizing enzyme-DNA-drug complexes at a stage in which the DNA gate strand is cleaved and the protein is covalently attached to DNA. Human small cell lung cancer NYH cells selected for resistance to ICRF-187 (NYH/187) showed a 25% increase in topoisomerase IIalpha level and no change...... in expression of the beta isoform. Sequencing of the entire topoisomerase IIalpha cDNA from NYH/187 cells demonstrated a homozygous G-->A point mutation at nucleotide 485, leading to a R162Q conversion in the Walker A consensus ATP binding site (residues 161-165 in the alpha isoform), this being the first drug......-selected mutation described at this site. Western blotting after incubation with ICRF-187 showed no depletion of the alpha isoform in NYH/187 cells in contrast to wild-type (wt) cells, whereas equal depletion of the beta isoform was observed in the two sublines. Alkaline elution assay demonstrated a lack...

  11. 4,6-Substituted-1,3,5-triazin-2(1H)-ones as monocyclic catalytic inhibitors of human DNA topoisomerase IIα targeting the ATP binding site.

    Science.gov (United States)

    Pogorelčnik, Barbara; Janežič, Matej; Sosič, Izidor; Gobec, Stanislav; Solmajer, Tom; Perdih, Andrej

    2015-08-01

    Human DNA topoisomerase IIα (htIIα) is a validated target for the development of novel anticancer agents. Starting from our discovered 4-amino-1,3,5-triazine inhibitors of htIIα, we investigated a library of 2,4,6-trisubstituted-1,3,5-triazines for novel inhibitors that bind to the htIIα ATP binding site using a combination of structure-based and ligand-based pharmacophore models and molecular docking. 4,6-substituted-1,3,5-triazin-2(1H)-ones 8, 9 and 14 were identified as novel inhibitors with activity comparable to the established drug etoposide (1). Compound 8 inhibits the htIIα decatenation in a superior fashion to etoposide. Cleavage assays demonstrated that selected compounds 8 and 14 do not act as poisons and antagonize the poison effect of etoposide. Microscale thermophoresis (MST) confirmed binding of compound 8 to the htIIα ATPase domain and compound 14 effectively inhibits the htIIα mediated ATP hydrolysis. The molecular dynamics simulation study provides further insight into the molecular recognition. The 4,6-disubstituted-1,3,5-triazin-2(1H)-ones represent the first validated monocyclic class of catalytic inhibitors that bind to the to the htIIα ATPase domain.

  12. 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)

  13. An ABC for decision making.

    Science.gov (United States)

    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.

  14. 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.

  15. 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.

  16. Applying the ABCs in provider organizations.

    Science.gov (United States)

    Pandey, Seema

    2012-11-01

    Activity-based costing (ABC) is an accounting technique designed to guard against potentially serious financial problems that can arise when an organization's accounting costs deviate significantly from its actual costs. In general, an ABC analysis considers two factors: a cost element (a directly measurable unit of cost, such as the cost of an item) and a cost driver (a directly measurable feature of the service, such as how often the item is used). ABC is best applied to specific service areas, orservice packages, for which consumption of resources is largely predictable and atomic units of services can be accurately identified.

  17. ABCs of Oral Health: Nutrition - Children

    Science.gov (United States)

    ... abnormal facial and dental development More ABCs of Oral Health A | B | C | D | E | F | G | H | ... games Home | InfoBites | Find a Dentist | Your Family's Oral Health | Newsroom | RSS About AGD | Contact AGD | Site Map | ...

  18. Transcription, Processing, and Function of CRISPR Cassettes in Escherichia coli

    OpenAIRE

    Pougach, Ksenia; Semenova, Ekaterina; Bogdanova, Ekaterina; Datsenko, Kirill A; Djordjevic, Marko; Wanner, Barry L.; Severinov, Konstantin

    2010-01-01

    CRISPR/Cas, bacterial and archaeal systems of interference with foreign genetic elements such as viruses or plasmids, consist of DNA loci called CRISPR cassettes (a set of variable spacers regularly separated by palindromic repeats) and associated cas genes. When a CRISPR spacer sequence exactly matches a sequence in a viral genome, the cell can become resistant to the virus. The CRISPR/Cas systems function through small RNAs originating from longer CRISPR cassette transcripts. While laborato...

  19. Sertraline and Its Metabolite Desmethylsertraline, but not Bupropion or Its Three Major Metabolites, Have High Affinity for P-Glycoprotein

    OpenAIRE

    Wang, Jun-Sheng; Zhu, Hao-Jie; Gibson, Bryan Bradford; Markowitz, John Seth; Donovan, Jennifer Lyn; DeVane, Carl Lindsay

    2008-01-01

    The ATP-binding cassette (ABC) transporter protein subfamily Bl line (ABCBl) transporter P-glycoprotein (P-gp) plays an important role in the blood–brain barrier limiting a broad spectrum of substrates from entering the central nervous system. In the present study, the transport activity of P-gp for sertraline, desmethylsertralin, bupropion, and the major metabolites of bupropion, threo-amino alcohol (TB), erythro-amino alchhol (EB), and hydroxy metabolite (HB) was studied using an ATPase ass...

  20. Bacterial transport of sulfate, molybdate, and related oxyanions.

    Science.gov (United States)

    Aguilar-Barajas, Esther; Díaz-Pérez, César; Ramírez-Díaz, Martha I; Riveros-Rosas, Héctor; Cervantes, Carlos

    2011-08-01

    Sulfur is an essential element for microorganisms and it can be obtained from varied compounds, sulfate being the preferred source. The first step for sulfate assimilation, sulfate uptake, has been studied in several bacterial species. This article reviews the properties of different bacterial (and archaeal) transporters for sulfate, molybdate, and related oxyanions. Sulfate uptake is carried out by sulfate permeases that belong to the SulT (CysPTWA), SulP, CysP/(PiT), and CysZ families. The oxyanions molybdate, tungstate, selenate and chromate are structurally related to sulfate. Molybdate is transported mainly by the high-affinity ModABC system and tungstate by the TupABC and WtpABC systems. CysPTWA, ModABC, TupABC, and WtpABC are homologous ATP-binding cassette (ABC)-type transporters with similar organization and properties. Uptake of selenate and chromate oxyanions occurs mainly through sulfate permeases.

  1. The ABC-paradox: is Time Driven ABC relevant for small and Medium sized enterprises (SME)?

    DEFF Research Database (Denmark)

    Fladkjær, Henrik Find; Jensen, Erling

    Several articles suggest that Activity Based Costing (ABC) has failed to succeed in practical use. It is even argued that we have an ABC-paradox. Activity Based Costing has won theoretically in nu-merous articles in journals, through books, being included in all major Business Accounting text...

  2. 姜黄素对脂变肝细胞胆固醇流出及ABCA1表达的影响%Effects of Curcumin on ATP Binding Cassette Transporter A1 Expression and Cholesterol Effiux in Human L-02 Hepatocyte

    Institute of Scientific and Technical Information of China (English)

    余其林; 阳学风

    2009-01-01

    目的 研究姜黄素对脂变肝细胞胆固醇的转运机制. 方法 取正常人肝L-02细胞作为研究对象.用10%(V/V)医用脂肪乳注射液和10%(V/V)胎牛血清的RPMI-1640完全培养基孵育24 h建立的脂肪变性肝细胞模型.实验分为为6个组,即正常肝细胞组、人肝L-02细胞脂肪变性模型组、姜黄素处理组(脂变细胞模型建立后,分别加入不等量姜黄素,使其终浓度分别为12.5、25、50、100 μmol/L).RT-PCR检测细胞ABCA1表达;高效液相色谱法定量检测细胞内外胆固醇含量. 结果 姜黄素呈浓度依赖性地减少细胞内脂变肝细胞内总胆固醇(TC)、胆固醇酯(CE)含量,增加培养基中游离胆固醇(FC)含量,同时增加ABCA1的表达. 结论 姜黄素能降低脂变人肝L-02细胞TC及CE含量,增加FC的外流;姜黄素增加脂变肝细胞胆固醇转运可能与ABCA1的上调有关.

  3. ATP结合盒转运子1R219K基因多态性与阿尔茨海默病相关性研究%Research on association between polymorphism of ATP-binding cassette transporter A1 and Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    王娟; 陈卫蓉; 肖志杰

    2013-01-01

    Objective To assess the effect of single-nucleotide polymorphisms (SNPs) in the cholesterol-related genes ABCA1 exon R219K variation on the risk of AD and cognitive function.Methods Using case-control study,a total of sporadic 104 AD patients and 104 individuals above 60 years without cognitive impairment from a population of Chinese Han nationality in Changsha area were studied to determine the polymorphisms of ABCA1 R219K.Adopt SPSS 13.0 for statistical analysis.Results There were significant differences in the frequencies of three genotypes (RR、RK and KK) between the AD patients and controls (x2 =8.777,P =0.012).The frequency of KK genotype in AD group is obviously lower than that of controls (x2 =5.261,P =0.022).The frequency of KK+RK genotype in AD patients was 54.8%,was significantly lower than that of controls (70.2%,P =0.022).There was significantly higher levels of HDL-C,apoA-I and cognitive scores in the carriers of KK genotype and K allele (P < 0.05).There was significantly higher levels of MMSE and WMS scores in the carriers of K K genotype and K allele (P < 0.05).Further in accordance with memory types including long-term memory,short-term memory,transient memory,compared with RR genotype,the scores of short-term memory,transient memory of RK,KK and RK + KK genotypes were higher (P < 0.05),but there was no significant difference in the score of long-term memory (P > 0.05).Multifactor logistic regression analysis showed that carrying K allele was a single protective factor for AD.Conclusions The polymorphism of ABCA1R219K is associated with AD.Carrying K allele may play a positive role in serum lipids and cognition,and produce a protective effect on risk of AD.%目的 探讨胆固醇相关基因ABCA1外显子R219K遗传变异对阿尔茨海默病(AD)发病风险及认知功能的影响.方法 采用病例对照研究方法测定湖南长沙地区汉族人群104例散发性AD患者以及104名60岁以上认知功能正常者的ABCA1R219K基因多态性.采用SPSS 13.0软件进行统计分析.结果 两组间RR、RK及KK 3种基因型分布差异有统计学意义(x2=8.777,P=0.012),AD组KK型频率显著低于对照组(x2=5.261,P=0.022).AD组(RK+KK)型频率较对照组显著降低(54.8% & 70.2%,P=0.022).KK型及K等位基因携带者血浆HDL—C、apoA-I水平增高,差异有统计学意义(P<0.05).在总体研究人群中,KK型及RK+ KK型携带者的MMSE评分以及WMS评分显著增高(P<0.05);进一步按照长时记忆、短时记忆和瞬时记忆3种记忆类型分析,与RR型相比,RK、KK型及RK+KK型携带者的短时记忆及瞬时记忆得分显著增高(P<0.05),而长时记忆得分的比较差异无统计学意义(P>0.05).Logistic回归结果表明K等位基因携带是AD发病的独立保护因素.结论 ABCA1R219K变异与AD的发病有关,K等住基因携带对血脂及认知功能可能产生有益作用,并对AD的发生可能有一定保护作用.

  4. An ABC analysis for power generation project

    Directory of Open Access Journals (Sweden)

    Batool Hasani

    2013-07-01

    Full Text Available One of the primary concerns on performance measurement is to know how much a particular project cost. However, using traditional method on project-based products often leads to inappropriate results. In this paper, we re-examine this issue by comparing the cost of a power station construction project using ABC versus traditional method. The results of survey show that ABC method is capable of providing better estimates for overhead costs compared with traditional method. In other words, ABC method helps reduce some of the unnecessary overhead cost items and increase on some other cost components. This helps increase the relative efficiency of the system by reducing total cost of project.

  5. Structural characterization of two metastable ATP-bound states of P-glycoprotein.

    Directory of Open Access Journals (Sweden)

    Megan L O'Mara

    Full Text Available ATP Binding Cassette (ABC transporters couple the binding and hydrolysis of ATP to the transport of substrate molecules across the membrane. The mechanism by which ATP binding and/or hydrolysis drives the conformational changes associated with substrate transport has not yet been characterized fully. Here, changes in the conformation of the ABC export protein P-glycoprotein on ATP binding are examined in a series of molecular dynamics simulations. When one molecule of ATP is placed at the ATP binding site associated with each of the two nucleotide binding domains (NBDs, the membrane-embedded P-glycoprotein crystal structure adopts two distinct metastable conformations. In one, each ATP molecule interacts primarily with the Walker A motif of the corresponding NBD. In the other, the ATP molecules interacts with both Walker A motif of one NBD and the Signature motif of the opposite NBD inducing the partial dimerization of the NBDs. This interaction is more extensive in one of the two ATP binding site, leading to an asymmetric structure. The overall conformation of the transmembrane domains is not altered in either of these metastable states, indicating that the conformational changes associated with ATP binding observed in the simulations in the absence of substrate do not lead to the outward-facing conformation and thus would be insufficient in themselves to drive transport. Nevertheless, the metastable intermediate ATP-bound conformations observed are compatible with a wide range of experimental cross-linking data demonstrating the simulations do capture physiologically important conformations. Analysis of the interaction between ATP and its cofactor Mg(2+ with each NBD indicates that the coordination of ATP and Mg(2+ differs between the two NBDs. The role structural asymmetry may play in ATP binding and hydrolysis is discussed. Furthermore, we demonstrate that our results are not heavily influenced by the crystal structure chosen for initiation

  6. Conformational cycle of the vitamin B12 ABC importer in liposomes detected by double electron-electron resonance (DEER).

    Science.gov (United States)

    Joseph, Benesh; Korkhov, Vladimir M; Yulikov, Maxim; Jeschke, Gunnar; Bordignon, Enrica

    2014-02-01

    Double electron-electron resonance is used here to investigate intermediates of the transport cycle of the Escherichia coli vitamin B12 ATP-binding cassette importer BtuCD-F. Previously, we showed the ATP-induced opening of the cytoplasmic gate I in TM5 helices, later confirmed by the AMP-PNP-bound BtuCD-F crystal structure. Here, other key residues are analyzed in TM10 helices (positions 307 and 322) and in the cytoplasmic gate II, i.e. the loop between TM2 and TM3 (positions 82 and 85). Without BtuF, binding of ATP induces detectable changes at positions 307 and 85 in BtuCD in liposomes. Together with BtuF, ATP triggers the closure of the cytoplasmic gate II in liposomes (reported by both positions 82 and 85). This forms a sealed cavity in the translocation channel in agreement with the AMP-PNP·BtuCD-F x-ray structure. When vitamin B12 and AMP-PNP are simultaneously present, the extent of complex formation is reduced, but the short 82-82 interspin distance detected indicates that the substrate does not affect the closed conformation of this gate. The existence of the BtuCD-F complex under these conditions is verified with spectroscopically orthogonal nitroxide and Gd(III)-based labels. The cytoplasmic gate II remains closed also in the vanadate-trapped state, but it reopens in the ADP-bound state of the complex. Therefore, we suggest that the substrate likely trapped in ATP·BtuCD-F can be released after ATP hydrolysis but before the occluded ADP-bound conformation is reached.

  7. New Broom To Sweep Clean At ABC

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Agricultural Bank of China (ABC) has a new president. The last non- publicly traded state-owned lender in China announced on July 6 that Xiang Junbo, former Vice Governor of the People’s Bank of China, or the central bank, had beenappointed to take o

  8. WeltABC | kinderKAMERA

    Directory of Open Access Journals (Sweden)

    Christian Schreger

    2013-09-01

    Full Text Available Das WeltABC ist eine Einladung zur Reise durch Sprache(n und damit verknüpften Bildern. Es ist eine Sammlung scheinbar klarer Begriffe, deren Ausgangspunkt die Sprache Deutsch ist. Diese Begriffe werden mit weiteren Begriffen assoziiert und durch Fotos illustriert.

  9. The ABC transporter ABC40 encodes a phenylacetic acid export system in Penicillium chrysogenum

    OpenAIRE

    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 phenylacetic acid (PAA) that is used for the biosynthesis of penicillin G. To identify ABC transporters related to beta-lactam biosynthesis, we analyzed the expression of all 48 ABC transporters presen...

  10. EFEKTIVITAS IMPLEMENTASI CORPORATE SOCIAL RESPOSIBILITY PT. ABC

    Directory of Open Access Journals (Sweden)

    Rizkiaji Rikky Djunaedi

    2015-12-01

    Full Text Available The purposes of this study were 1 to analyze public perceptions on the effectiveness of the implementation of CSR of PT. A B C; 2 to analyze the implementation of CSR activities by PT. A B C; 3 to formulate strategies to improve the effectiveness of the implementation of CSR of PT. A B C. The method used in this research was descriptive analysis with a survey approach to measure expectations and performance assessment on the CSR implemented programs by the public, and there were respondents 104 respondents involved in this study. This study used the Importance-Performance Analysis (IPA aiming to determine the effectiveness of the programs that have been implemented and to map the relationship between the expectations and the performance of each variable. Furthermore, using a SWOT analysis of the data processing and of the objectives of the program made by CSR is expected to provide recommendations to develop strategies in order to increase the effectiveness of CSR program of ABC Company.Keywords: corporate social responsibility (CSR, mining industry, implementation analysis, IPA, SWOTAbstrakTujuan dari  penelitian ini adalah 1 menganalisis persepsi masyarakat teradap efektivitas implementasi CSR PT. ABC; 2 menganalisis pelaksanaan  kegiatan CSR oleh PT. ABC; 3 merumuskan strategi untuk meningkatkan efektivitas implementasi CSR PT. ABC. Metode yang digunakan dalam penelitian ini adalah analisis deskriptif dengan pendekatan survey untuk mengukur harapan dan penilaian kinerja oleh masyarakat atas program CSR yang diterapkan. Jumlah responden sebanyak 104 orang.  Dalam penelitian ini digunakan Analisis Importance-Performance Analysis (IPA bertujuan untuk mengetahui efektifitas dari program-program yang telah dijalankan serta  memetakan hubungan antara harapan dengan kinerja dari masing-masing variabel. Selanjutnya menggunakan analisis SWOT dari hasil pengolahan data dan dari tujuan program dibuat oleh CSR sehingga dapat memberikan rekomendasi

  11. Co-assortment in integron-associated gene cassette assemblages in environmental DNA samples

    Directory of Open Access Journals (Sweden)

    Michael Carolyn A

    2010-08-01

    Full Text Available Abstract Background It has been shown that integron-associated gene cassettes exist largely in tandem arrays of variable size, ranging from antibiotic resistance arrays of three to five cassettes up to arrays of more than 100 cassettes associated with the vibrios. Further, the ecology of the integron/gene cassette system has been investigated by showing that very many different cassettes are present in even small environmental samples. In this study, we seek to extend the ecological perspective on the integron/gene cassette system by investigating the way in which this diverse cassette metagenome is apportioned amongst prokaryote lineages in a natural environment. Results We used a combination of PCR-based techniques applied to environmental DNA samples and ecological analytical techniques to establish co-assortment within cassette populations, then establishing the relationship between this co-assortment and genomic structures. We then assessed the distribution of gene cassettes within the environment and found that the majority of gene cassettes existed in large co-assorting groups. Conclusions Our results suggested that the gene cassette diversity of a relatively pristine sampling environment was structured into co-assorting groups, predominantly containing large numbers of cassettes per group. These co-assorting groups consisted of different gene cassettes in stoichiometric relationship. Conservatively, we then attributed co-assorting cassettes to the gene cassette complements of single prokaryote lineages and by implication, to large integron-associated arrays. The prevalence of large arrays in the environment raises new questions about the assembly, maintenance and utility of large cassette arrays in prokaryote populations.

  12. 21 CFR 892.1880 - Wall-mounted radiographic cassette holder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wall-mounted radiographic cassette holder. 892.1880 Section 892.1880 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... radiographic cassette holder. (a) Identification. A wall-mounted radiographic cassette holder is a device...

  13. THE ROLE OF MULTIDRUG RESISTANCE ASSOCIATED PROTEIN (MRP) IN THE BLOOD-BRAIN BARRIER AND OPIOID ANALGESIA

    OpenAIRE

    Su, Wendy; Pasternak, Gavril W.

    2013-01-01

    The blood brain barrier protects the brain from circulating compounds and drugs. The ATP-binding cassette (ABC) transporter P-glycoprotein (Pgp) is involved with the barrier, both preventing the influx of agent from the blood into the brain and facilitating the efflux of compounds from the brain into the blood, raising the possibility of a similar role for other transporters. Multidrug resistance associated protein (MRP), a 190 kDa protein similar to Pgp is also ABC transport that has been im...

  14. Nonintegral stoichiometry in CFTR gating revealed by a pore-lining mutation

    OpenAIRE

    Jih, Kang-Yang; Sohma, Yoshiro; Hwang, Tzyh-Chang

    2012-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) is a unique member of the ATP-binding cassette (ABC) protein superfamily. Unlike most other ABC proteins that function as active transporters, CFTR is an ATP-gated chloride channel. The opening of CFTR’s gate is associated with ATP-induced dimerization of its two nucleotide-binding domains (NBD1 and NBD2), whereas gate closure is facilitated by ATP hydrolysis-triggered partial separation of the NBDs. This generally held theme of CFTR ...

  15. MANFAAT DATA WAREHOUSE PADA PT ABC

    Directory of Open Access Journals (Sweden)

    Evaristus Didik Madyatmadja

    2013-11-01

    Full Text Available The purpose of this paper is to analyze the current system to find out problems faced by the company and propose alternative solutions and generate information needed by management by designing a data warehouse according to the information needs of PT ABC. This research implements analysis and design of data warehouse by Ralph Kimball and Ross cited by Connolly and Begg, known as Nine-Step Methodology. The result obtained is a data warehouse application that may present a multidimensional historical data that can assist the management in decisions. Designing data warehouse at PT ABC makes concise the enterprise data and can be viewed from several dimensions. It helps users analyze data for strategic decision quickly and accurately.

  16. ABC of physics a very brief guide

    CERN Document Server

    Okun, Lev Borisovich

    2012-01-01

    This little book concentrates on the foundations of modern physics (its "ABC's") and its most fundamental constants: c - the velocity of light and ? - the quantum of action. First of all, the book is addressed to professional physicists, but in order to achieve maximal concentration and clarity it uses the simplest (high school) mathematics. As a result many pages of the book will be useful to college students and may appeal to a more general audience.

  17. Fast correlation attack on stream cipher ABC v3

    Institute of Scientific and Technical Information of China (English)

    ZHANG HaiNa; LI Lin; WANG XiaoYun

    2008-01-01

    ABC v3 is a stream cipher submitted to the ECRYPT eStream project and has entered the second evaluation phase.Its key length is 128 bits.In this paper,we find large numbers of new weak keys of ABC family and introduce a method to search for them,and then apply a fast correlation attack to break ABC v3 with weak keys.We show that there are at least 2103.71 new weak keys in ABC v3.Recovering the internal state of a weak key requires 236.05 keystream words and 250.56 operations.The attack can be applied to ABC v1 and v2 with the same complexity as that of ABC v3.However,the number of weak keys of ABC v1 as well as ABC v2 decreases to 297+295.19.It reveals that ABC v3 incurs more weak keys than that of ABC v1 and v2.

  18. Expression of antibiotic resistance genes in the integrated cassettes of integrons.

    Science.gov (United States)

    Collis, C M; Hall, R M

    1995-01-01

    Plasmids containing cloned integron fragments which differ only with respect to either the sequence of the promoter(s) or the number and order of inserted cassettes were used to examine the expression of resistance genes encoded in integron-associated gene cassettes. All transcripts detected commenced at the common promoter P(ant), and alterations in the sequence of P(ant) affected the level of resistance expressed by cassette genes. When both P(ant) and the secondary promoter P2 were present, transcription from both promoters was detected. When more than one cassette was present, the position of the cassette in the array influenced the level of antibiotic resistance expressed by the cassette gene. In all cases, the resistance level was highest when the gene was in the first cassette, i.e., closest to P(ant), and was reduced to different extents by the presence of individual upstream cassettes. In Northern (RNA) blots, multiple discrete transcripts originating at P(ant) were detected, and only the longer transcripts contained the distal genes. Together, these data suggest that premature transcription termination occurs within the cassettes. The most abundant transcripts appeared to contain one or more complete cassettes, and is possible that the 59-base elements found at the end of the cassettes (3' to the coding region) not only function as recombination sites but may also function as transcription terminators. PMID:7695299

  19. p21-ras effector domain mutants constructed by "cassette" mutagenesis

    DEFF Research Database (Denmark)

    Stone, J C; Vass, W C; Willumsen, B M;

    1988-01-01

    A series of mutations encoding single-amino-acid substitutions within the v-rasH effector domain were constructed, and the ability of the mutants to induce focal transformation of NIH 3T3 cells was studied. The mutations, which spanned codons 32 to 40, were made by a "cassette" mutagenesis...... technique that involved replacing this portion of the v-rasH effector domain with a linker carrying two BspMI sites in opposite orientations. Since BspMI cleaves outside its recognition sequence, BspMI digestion of the plasmid completely removed the linker, creating a double-stranded gap whose missing ras...... sequences were reconstructed as an oligonucleotide cassette. Based upon the ability of the mutants to induce focal transformation of NIH 3T3 cells, a range of phenotypes from virtually full activity to none (null mutants) was seen. Three classes of codons were present in this segment: one which could...

  20. A simplified erythromycin resistance cassette for Treponema denticola mutagenesis

    Science.gov (United States)

    Goetting-Minesky, M. Paula; Fenno, J. Christopher

    2010-01-01

    The primary selectable marker for genetic studies of Treponema denticola is a hybrid gene cassette containing both ermF and ermAM (ermB) genes. ErmB functions in Escherichia coli, while ErmF has been assumed to confer resistance in T. denticola. We demonstrate here that ErmB is sufficient for erythromycin selection in T. denticola and that the native ermB promoter drives ErmB expression. PMID:20691222

  1. Cassette less SOFC stack and method of assembly

    Science.gov (United States)

    Meinhardt, Kerry D

    2014-11-18

    A cassette less SOFC assembly and a method for creating such an assembly. The SOFC stack is characterized by an electrically isolated stack current path which allows welded interconnection between frame portions of the stack. In one embodiment electrically isolating a current path comprises the step of sealing a interconnect plate to a interconnect plate frame with an insulating seal. This enables the current path portion to be isolated from the structural frame an enables the cell frame to be welded together.

  2. Polycistronic transcription of fused cassettes and identification of translation initiation signals in an unusual gene cassette array from Pseudomonas aeruginosa [version 3; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Érica L. Fonseca

    2015-11-01

    Full Text Available The gene cassettes found in class 1 integrons are generally promoterless units composed by an open reading frame (ORF, a short 5’ untranslated region (UTR and a 3’ recombination site (attC. Fused gene cassettes are generated by partial or total loss of the attC from the first cassette in an array, creating, in some cases, a fusion with the ORF from the next cassette. These structures are rare and little is known about their mechanisms of mobilization and expression. The aim of this study was to evaluate the dynamic of mobilization and transcription of the gcu14-blaGES-1/aacA4 gene cassette array, which harbours a fused gene cassette represented by blaGES-1/aacA4. The cassette array was analyzed by Northern blot and real-time reverse transcription-polymerase chain reaction (RT-PCR in order to assess the transcription mechanism of blaGES-1/aacA4 fused cassette. Also, inverse polymerase chain reactions (PCR were performed to detect the free circular forms of gcu14, blaGES-1 and aacA4. The Northern blot and real time RT-PCR revealed a polycistronic transcription, in which the fused cassette blaGES-1/aacA4 is transcribed as a unique gene, while gcu14 (with a canonical attC recombination site has a monocistronic transcription. The gcu14 cassette, closer to the weak configuration of cassette promoter (PcW, had a higher transcription level than blaGES-1/aacA4, indicating that the cassette position affects the transcript amounts. The presence of ORF-11 at attI1, immediately preceding gcu14, and of a Shine-Dalgarno sequence upstream blaGES-1/aacA4 composes a scenario for the occurrence of array translation. Inverse PCR generated amplicons corresponding to gcu14, gcu14-aacA4 and gcu14-blaGES-1/aacA4 free circular forms, but not to blaGES-1 and aacA4 alone, indicating that the GES-1 truncated attC is not substrate of integrase activity and that these genes are mobilized together as a unique cassette. This study was original in showing the transcription

  3. Overcoming Multidrug Resistance in Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Karobi Moitra

    2015-01-01

    Full Text Available The principle mechanism of protection of stem cells is through the expression of ATP-binding cassette (ABC transporters. These transporters serve as the guardians of the stem cell population in the body. Unfortunately these very same ABC efflux pumps afford protection to cancer stem cells in tumors, shielding them from the adverse effects of chemotherapy. A number of strategies to circumvent the function of these transporters in cancer stem cells are currently under investigation. These strategies include the development of competitive and allosteric modulators, nanoparticle mediated delivery of inhibitors, targeted transcriptional regulation of ABC transporters, miRNA mediated inhibition, and targeting of signaling pathways that modulate ABC transporters. The role of ABC transporters in cancer stem cells will be explored in this paper and strategies aimed at overcoming drug resistance caused by these particular transporters will also be discussed.

  4. Smooth solutions to the equation A+B=C

    CERN Document Server

    Lagarias, Jeffrey C

    2009-01-01

    This paper studies integer solutions to the ABC equation A+B+C=0 in which none of A, B, C has a large prime factor. Set H(A,B, C)= max(|A|,|B|,|C|) and set the smoothness S(A, B, C) to be the largest prime factor of ABC. We consider primitive solutions (gcd(A, B, C)=1) having smoothness no larger than a fixed power p of log H. Assuming the abc Conjecture we show that there are finitely many solutions if p8. We sketch some details of the proof of the latter result.

  5. APOLLO 13: A News Bulletin from ABC

    Science.gov (United States)

    1974-01-01

    APOLLO 13: ABC breaks the news of a mishap aboard the spacecraft From the film documentary 'APOLLO 13: 'Houston, We've got a problem'', part of a documentary series on the APOLLO missions made in the early '70's and narrated by Burgess Meredith. APOLO 13 : Third manned lunar landing attempt with James A. Lovell, Jr., John L. Swigert, Jr., and Fred W. Haise, Jr. Pressure lost in SM oxygen system; mission aborted; LM used for life support. Mission Duration 142hrs 54mins 41sec

  6. 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...... 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...

  7. The A-B-C of recycling

    DEFF Research Database (Denmark)

    Thøgersen, John; Ølander, Carl Folke

    specifically the source separation of compostable kitchen waste. The investigation was carried out before and after the introduction of a system, facilitating such separation, in a Danish community. Hypotheses derived from the A-B-C model, predicting that changes over time in the correlation between attitude......A general framework for interpreting behaviour as co-determined by attitudes and structural conditions, developed by Guagnano, Stern, and Dietz for the field of environmental psychology but with general applicability, is used to identify determinants of consumers' recycling behaviour, more...

  8. 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.

  9. Cassettes for solid-oxide fuel cell stacks and methods of making the same

    Science.gov (United States)

    Weil, K. Scott; Meinhardt, Kerry D; Sprenkle, Vincent L

    2012-10-23

    Solid-oxide fuel cell (SOFC) stack assembly designs are consistently investigated to develop an assembly that provides optimal performance, and durability, within desired cost parameters. A new design includes a repeat unit having a SOFC cassette and being characterized by a three-component construct. The three components include an oxidation-resistant, metal window frame hermetically joined to an electrolyte layer of a multi-layer, anode-supported ceramic cell and a pre-cassette including a separator plate having a plurality of vias that provide electrical contact between an anode-side collector within the pre-cassette and a cathode-side current collector of an adjacent cell. The third component is a cathode-side seal, which includes a standoff that supports a cathode channel spacing between each of the cassettes in a stack. Cassettes are formed by joining the pre-cassette and the window frame.

  10. Recombinogenic engineering of conjugative plasmids with fluorescent marker cassettes

    DEFF Research Database (Denmark)

    Reisner, A.; Molin, Søren; Zechner, E.L.

    2002-01-01

    An efficient approach for the insertion of fluorescent marker genes with sequence specificity into conjugative plasmids in Escherichia coli is described. For this purpose, homologous recombination of linear double-stranded targeting DNA was mediated by the bacteriophage lambda recombination...... resistance genes and fluorescent markers. The choice of 5' non-homologous extensions in primer pairs used for amplifying the marker cassettes determines the site specificity of the targeting DNA. This methodology is applicable to the modification of all plasmids that replicate in E coli and is not restricted...

  11. 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- c assette (ABC) superfamily. The ABC tr

  12. abc: The AspectBench Compiler for AspectJ

    DEFF Research Database (Denmark)

    Allan, Chris; Avgustinov, Pavel; Christensen, Aske Simon;

    2005-01-01

    abc is an extensible, optimising compiler for AspectJ. It has been designed as a workbench for experimental research in aspect-oriented programming languages and compilers. We outline a programme of research in these areas, and we review how abc can help in achieving those research goals...

  13. 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.

  14. Resistance to Bacillus thuringiensis Mediated by an ABC Transporter Mutation Increases Susceptibility to Toxins from Other Bacteria in an Invasive Insect.

    Directory of Open Access Journals (Sweden)

    Yutao Xiao

    2016-02-01

    Full Text Available 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.

  15. 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

  16. Gene amplification, ABC transporters and cytochrome P450s: unraveling the molecular basis of pyrethroid resistance in the dengue vector, Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Vassiliki Bariami

    Full Text Available BACKGROUND: Pyrethroid insecticides are widely utilized in dengue control. However, the major vector, Aedes aegypti, is becoming increasingly resistant to these insecticides and this is impacting on the efficacy of control measures. The near complete transcriptome of two pyrethroid resistant populations from the Caribbean was examined to explore the molecular basis of this resistance. PRINCIPAL FINDINGS: Two previously described target site mutations, 1016I and 1534C were detected in pyrethroid resistant populations from Grand Cayman and Cuba. In addition between two and five per cent of the Ae. aegypti transcriptome was differentially expressed in the resistant populations compared to a laboratory susceptible population. Approximately 20 per cent of the genes over-expressed in resistant mosquitoes were up-regulated in both Caribbean populations (107 genes. Genes with putative monooxygenase activity were significantly over represented in the up-regulated subset, including five CYP9 P450 genes. Quantitative PCR was used to confirm the higher transcript levels of multiple cytochrome P450 genes from the CYP9J family and an ATP binding cassette transporter. Over expression of two genes, CYP9J26 and ABCB4, is due, at least in part, to gene amplification. SIGNIFICANCE: These results, and those from other studies, strongly suggest that increases in the amount of the CYP9J cytochrome P450s are an important mechanism of pyrethroid resistance in Ae. aegypti. The genetic redundancy resulting from the expansion of this gene family makes it unlikely that a single gene or mutation responsible for pyrethroid resistance will be identified in this mosquito species. However, the results from this study do pave the way for the development of new pyrethroid synergists and improved resistance diagnostics. The role of copy number polymorphisms in detoxification and transporter genes in providing protection against insecticide exposure requires further investigation.

  17. An AC electrokinetics facilitated biosensor cassette for rapid pathogen identification.

    Science.gov (United States)

    Ouyang, Mengxing; Mohan, Ruchika; Lu, Yi; Liu, Tingting; Mach, Kathleen E; Sin, Mandy L Y; McComb, Mason; Joshi, Janhvi; Gau, Vincent; Wong, Pak Kin; Liao, Joseph C

    2013-07-01

    To develop a portable point-of-care system based on biosensors for common infectious diseases such as urinary tract infection, the sensing process needs to be implemented within an enclosed fluidic system. On chip sample preparation of clinical samples remains a significant obstacle to achieving robust sensor performance. Herein AC electrokinetics is applied in an electrochemical biosensor cassette to enhance molecular convection and hybridization efficiency through electrokinetics induced fluid motion and Joule heating induced temperature elevation. Using E. coli as an exemplary pathogen, we determined the optimal electrokinetic parameters for detecting bacterial 16S rRNA in the biosensor cassette based on the current output, signal-to-noise ratio, and limit of detection. In addition, a panel of six probe sets targeting common uropathogenic bacteria was demonstrated. The optimized parameters were also validated using patient-derived clinical urine samples. The effectiveness of electrokinetics for on chip sample preparation will facilitate the implementation of point-of-care diagnosis of urinary tract infection in the future.

  18. Recovery and evolutionary analysis of complete integron gene cassette arrays from Vibrio

    Directory of Open Access Journals (Sweden)

    Gillings Michael R

    2006-01-01

    Full Text Available Abstract Background Integrons are genetic elements capable of the acquisition, rearrangement and expression of genes contained in gene cassettes. Gene cassettes generally consist of a promoterless gene associated with a recombination site known as a 59-base element (59-be. Multiple insertion events can lead to the assembly of large integron-associated cassette arrays. The most striking examples are found in Vibrio, where such cassette arrays are widespread and can range from 30 kb to 150 kb. Besides those found in completely sequenced genomes, no such array has yet been recovered in its entirety. We describe an approach to systematically isolate, sequence and annotate large integron gene cassette arrays from bacterial strains. Results The complete Vibrio sp. DAT722 integron cassette array was determined through the streamlined approach described here. To place it in an evolutionary context, we compare the DAT722 array to known vibrio arrays and performed phylogenetic analyses for all of its components (integrase, 59-be sites, gene cassette encoded genes. It differs extensively in terms of genomic context as well as gene cassette content and organization. The phylogenetic tree of the 59-be sites collectively found in the Vibrio gene cassette pool suggests frequent transfer of cassettes within and between Vibrio species, with slower transfer rates between more phylogenetically distant relatives. We also identify multiple cases where non-integron chromosomal genes seem to have been assembled into gene cassettes and others where cassettes have been inserted into chromosomal locations outside integrons. Conclusion Our systematic approach greatly facilitates the isolation and annotation of large integrons gene cassette arrays. Comparative analysis of the Vibrio sp. DAT722 integron obtained through this approach to those found in other vibrios confirms the role of this genetic element in promoting lateral gene transfer and suggests a high rate of gene

  19. An investigation of infection control for x-ray cassettes in a diagnostic imaging department

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Matthew [School of Allied Health Professions and Science, Faculty of Health, Wellbeing and Science, University Campus Suffolk, Rope Walk, Ipswich, Suffolk, IP4 1LT (United Kingdom); Harvey, Jane M. [School of Allied Health Professions and Science, Faculty of Health, Wellbeing and Science, University Campus Suffolk, Rope Walk, Ipswich, Suffolk, IP4 1LT (United Kingdom)], E-mail: j.harvey@ucs.ac.uk

    2008-11-15

    Introduction: This research was conducted to investigate if X-ray cassettes could be a possible source of pathogens capable of causing nosocomial infections, and if they could be a possible vector for cross infection within the hospital environment. Method: The research involved the swabbing of X-ray cassettes in a Diagnostic Imaging Department of a large hospital in the east of England. Two areas of the Diagnostic Imaging Department were included in the study. Research concentrated on X-ray cassettes used for mobile radiography, accident and emergency and inpatient use. Forty cassettes were swabbed in total specifically for general levels of bacterial contamination, also for the presence or absence of methicillin-resistant Staphylococcus aureus (MRSA). A mapping exercise was completed following the location of an X-ray cassette typically used in mobile radiography. The exercise noted the level of direct contact with patient's skin and other possible routes of infection. Results: The results demonstrated that there were large levels of growth of samples taken from cassettes and developed in the Microbiology Department. Coagulase-negative Staphylococcus, Micrococci, Diptheroids and species of Bacillus were all identified. The mapping exercise in which the journey of a 35/43 cm cassette used for mobile radiography was tracked found that contact with patient's skin and potential pathogens or routes of cross infection was a common occurrence whilst undertaking mobile radiography. Conclusion: The research has identified the presence of bacterial contamination on cassettes. The research established that X-ray cassettes/imaging plates are often exposed to pathogens and possible routes of cross infection; also that patient's skin often comes directly in contact with the X-ray cassette/imaging plate. The research also shows that as cassettes/imaging plates are a potential source of cross infection, the Diagnostic Imaging Department may be partly responsible

  20. ABC for network managers. Key to efficiency improvement; ABC voor netbeheerders. Sleutel tot efficiencyverbetering

    Energy Technology Data Exchange (ETDEWEB)

    Osse, M.J.E. [Ernst and Young Consulting, Utrecht (Netherlands)

    1999-12-01

    In order to give everyone who wants to supply electricity a fair chance, network managers must make costs transparent. Next to the rules for the tariff code, they can also make use of a cost charging method, the so-called ABC-N (Activity Based Costing for Networks). This method makes the costs transparent and therefore also helps the network managers to improve their efficiency. That is essential in view of the pressure from the supervisor for the Dutch electric power sector.

  1. 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.

  2. Syntheses, photophysical properties, and application of through-bond energy-transfer cassettes for biotechnology.

    Science.gov (United States)

    Jiao, Guan-Sheng; Thoresen, Lars H; Kim, Taeg Gyum; Haaland, Wade C; Gao, Feng; Topp, Michael R; Hochstrasser, Robin M; Metzker, Michael L; Burgess, Kevin

    2006-10-16

    We have designed fluorescent "through-bond energy-transfer cassettes" that can harvest energy of a relatively short wavelength (e.g., 490 nm), and emit it at appreciably longer wavelengths without significant loss of intensity. Probes of this type could be particularly useful in biotechnology for multiplexing experiments in which several different outputs are to be observed from a single excitation source. Cassettes 1-4 were designed, prepared, and studied as model systems to achieve this end. They were synthesized through convergent routes that feature coupling of specially prepared fluorescein- and rhodamine-derived fragments. The four cassettes were shown to emit strongly, with highly efficient energy transfer. Their emission maxima cover a broad range of wavelengths (broader than the four dye cassettes currently used for most high-throughput DNA sequencing), and they exhibit faster energy-transfer rates than a similar through-space energy-transfer cassette. Specifically, energy-transfer rates in these cassettes is around 6-7 ps, in contrast to a similar through-space energy-transfer system shown to have a decay time of around 35 ps. Moreover, the cassettes are considerably more stable to photobleaching than fluorescein, even though they each contain fluorescein-derived donors. This was confirmed by bulk fluorescent measurements, and in single-molecule-detection studies. Modification of a commercial automated DNA-sequencing apparatus to detect the emissions of these four energy-transfer cassettes enabled single-color dye-primer sequencing.

  3. Natural transformation with synthetic gene cassettes: new tools for integron research and biotechnology.

    Science.gov (United States)

    Gestal, Alicia M; Liew, Elissa F; Coleman, Nicholas V

    2011-12-01

    Integrons are genetic elements that can capture and express genes packaged as gene cassettes. Here we report new methods that allow integrons to be studied and manipulated in their native bacterial hosts. Synthetic gene cassettes encoding gentamicin resistance (aadB) and green fluorescence (gfp), or lactose metabolism (lacZY), were made by PCR and self-ligation, converted to large tandem arrays by multiple displacement amplification, and introduced into Escherichia coli or Pseudomonas stutzeri strains via electroporation or natural transformation. Recombinants (Gm(R) or Lac(+)) were obtained at frequencies ranging from 10(1) to 10(6) c.f.u. (µg DNA)(-1). Cassettes were integrated by site-specific recombination at the integron attI site in nearly all cases examined (370/384), including both promoterless and promoter-containing cassettes. Fluorometric analysis of gfp-containing recombinants revealed that expression levels from the integron-associated promoter P(C) were five- to 10-fold higher in the plasmid-borne integron In3 compared with the P. stutzeri chromosomal integrons. Integration of lacZY cassettes into P. stutzeri integrons allowed the bacteria to grow on lactose, and the lacZY gene cassette was stably maintained in the absence of selection. This study is believed to be the first to show natural transformation by gene cassettes, and integron-mediated capture of catabolic gene cassettes.

  4. A New Activity-Based Cost (ABC) Mathematical Model

    Institute of Scientific and Technical Information of China (English)

    JIANG Shuo; SONG Lei

    2003-01-01

    Along with the product price competition growing intensely, it is apparently important for reasonably distributing and counting cost. But, in sharing indirect cost, traditional cost accounting unveils the limitations increasingly, especially in authenticity of cost information. And the accounting theory circles and industry circles begin seeking one kind of new accurate cost calculation method, and the activity-based cost (ABC) method emerges as the times require. In this paper, we will build its mathematical model by the basic principle of ABC, and will improve its mathematical model further. We will establish its comparison mathematical model and make the ABC method go a step further to its practical application.

  5. The intact CFTR protein mediates ATPase rather than adenylate kinase activity.

    Science.gov (United States)

    Ramjeesingh, Mohabir; Ugwu, Francisca; Stratford, Fiona L L; Huan, Ling-Jun; Li, Canhui; Bear, Christine E

    2008-06-01

    The two NBDs (nucleotide-binding domains) of ABC (ATP-binding-cassette) proteins function in a complex to mediate ATPase activity and this activity has been linked to their regulated transport activity. A similar model has been proposed for CFTR (cystic fibrosis transmembrane conductance regulator), the chloride channel defective in cystic fibrosis, wherein ATP binding and hydrolysis regulate the channel gate. Recently, it was shown that the individual NBDs isolated from CFTR primarily mediate adenylate kinase activity, raising the possibility that this activity may also contribute to gating of the CFTR channel. However, this present study shows that whereas the isolated NBDs exhibit adenylate kinase activity, the full-length purified and reconstituted CFTR protein functions as an ATPase, arguing that the enzymatic activity of the NBDs is dependent on their molecular context and appropriate domain-domain assembly. As expected, the disease-causing mutant bearing a mutation in the ABC signature motif, CFTR-G551D, exhibited a markedly reduced ATPase activity. Furthermore, mutation of the putative catalytic base in CFTR caused a reduction in ATPase activity, with the CFTR-E1371Q mutant supporting a low level of residual activity. Neither of these mutants exhibited detectable adenylate kinase activity. Together, these findings support the concept that the molecular mechanism of action of CFTR is dependent on ATP binding and hydrolysis, and that the structure of prokaryotic ABC ATPases provide a useful template for understanding their mechanism of action.

  6. Examination of the nature of the ABC effect

    Science.gov (United States)

    Bashkanov, M.; Clement, H.; Skorodko, T.

    2017-02-01

    Recently it has been shown by exclusive and kinematically complete experiments that the appearance of a narrow resonance structure in double-pionic fusion reactions is strictly correlated with the appearance of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the ππ-invariant mass spectrum. Whereas the resonance structure got its explanation by the d* (2380) dibaryonic resonance, a satisfactory explanation for the ABC effect is still pending. In this paper we discuss possible explanations of the ABC effect and their consequences for the internal structure of the d* dibaryon. To this end we examine and review a variety of proposed explanations for the ABC effect, add a new hypothesis and confront all of them with the experimental results for the np → dπ0π0 and np → npπ0π0 reactions, which are the most challenging ones for this topic.

  7. MDR-ABC transporters: biomarkers in rheumatoid arthritis.

    Science.gov (United States)

    Márki-Zay, János; Tauberné Jakab, Katalin; Szerémy, Péter; Krajcsi, Peter

    2013-01-01

    MDR-ABC transporters are widely expressed in cell types relevant to pathogenesis of rheumatoid arthritis. Many reports demonstrate the interaction of small molecule drugs with MDR-ABC transporters. Cell-based assays for disease relevant cell types can be easily gated and could reveal specific drug targets and may increase significance and utilisation of data in clinical practice. Many commonly used DMARDs (e.g. methotrexate, sulfasalazine, leflunomide/teriflunomide, hydroxychloroquine) are ABCG2 substrates. Consequently, the activity of this transporter in patients should be determined to understand the disposition and pharmacokinetics of the therapy. In addition, MDR-ABC transporters transport a variety of endobiotics that play important roles in cell proliferation, cell migration, angiogenesis and inflammation. Therefore, MDR-ABC transporters are important biomarkers in rheumatoid arthritis.

  8. Yang-Mills Theory and the ABC Conjecture

    CERN Document Server

    He, Yang-Hui; Probst, Malte; Read, James

    2016-01-01

    We establish a precise correspondence between the ABC Conjecture and N=4 super-Yang-Mills theory. This is achieved by combining three ingredients: (i) Elkies' method of mapping ABC-triples to elliptic curves in his demonstration that ABC implies Mordell/Faltings; (ii) an explicit pair of elliptic curve and associated Belyi map given by Khadjavi-Scharaschkin; and (iii) the fact that the bipartite brane-tiling/dimer model for a gauge theory with toric moduli space is a particular dessin d'enfant in the sense of Grothendieck. We explore this correspondence for the highest quality ABC-triples as well as large samples of random triples. The Conjecture itself is mapped to a statement about the fundamental domain of the toroidal compactification of the string realization of N=4 SYM.

  9. Multicompartment Micelles From π-Shaped ABC Block Copolymers

    Institute of Scientific and Technical Information of China (English)

    XIA Jun; ZHONG Chong-Li

    2007-01-01

    Dissipative particle dynamics simulations were performed on the morphology and structure of multicompartment micelles formed from n-shaped ABC block copolymers in water. The influences of chain architectures were studied in a systematic way, and a rich variety of morphologies were observed, such as spherical, wormlike,X-shaped, Y-shaped, ribbon-like, layered rod-like, layered disk-like, as well as network morphologies. The simulations show that the distance between the two grafts plays an important role in control of the morphology. Since π-shaped ABC block copolymers can be reduced to linear ABC and star ABC block copolymers, they are good model copolymers for studying the self-assembly of complex block copolymers into micelles. The knowledge obtained in this work as well as the new morphologies identified provide useful information for future rational design and synthesis of novel multicompartment micelles.

  10. 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...... language. The use of Polyglot gives flexibility of syntax and type checking. The back end 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 of how to use abc to implement an extension. We illustrate the extension mechanisms of abc through a number of small, but nontrivial, examples. We then proceed to contrast the design goals of abc with those of the original AspectJ compiler, and how these different goals have led to different...

  11. Redundancy Level Optimization in Modular Software System Models using ABC

    Directory of Open Access Journals (Sweden)

    Tarun Kumar Sharma

    2014-03-01

    Full Text Available The performance of optimization algorithms is problem dependent and as per no free lunch theorem, there exists no such algorithm which can be efficiently applied to every type of problem(s. However, we can modify the algorithm/ technique in a manner such that it is able to deal with a maximum type of problems. In this study we have modified the structure of basic Artificial Bee Colony (ABC, a recently proposed metaheuristic algorithm based on the concept of swarm intelligence to optimize the models of software reliability. The modified variant of ABC is termed as balanced ABC (B-ABC. The simulated results show the efficiency and capability of the variant to solve such type of the problems.

  12. The ABC daycare disaster of Hermosillo, Mexico.

    Science.gov (United States)

    Greenhalgh, David G; Chang, Philip; Maguina, Pirko; Combs, Elena; Sen, Soman; Palmieri, Tina L

    2012-01-01

    On June 5, 2009, the ABC Daycare facility in Hermosillo, Mexico, caught on fire with an estimated 142 children and 6 adult caregivers inside. The purpose of this article is to describe the factors contributing to the disaster including care of the survivors, tertiary burn center triage, patient transport, and treatment for this international mass casualty event. Finally, the results of an investigation performed by the Mexican Government are reviewed. A summary of the Mexican Government's investigation of the circumstances of fire and an examination of prevention lapses in other Mexican daycare centers was obtained from their public Web site. The demographic and clinical characteristics of the children transported to the burn center were obtained from the patients' medical records and transport data sheets. The ABC Daycare had many fire safety breaches that contributed to the severity of the tragedy. Twenty-nine children died at the scene and more than 35 children were hospitalized throughout Mexico. A total of 12 children were transported to two Shriners Hospitals, 9 to Sacramento, and 3 to Cincinnati. The mean age of patients sent to the Shriners Hospitals was 2.9 ± 0.16 years (2-4 years), with 5 being male and 7 female. The mean duration between injury and arrival was 9.2 ± 2.1 days, the burn size was 43.0 ± 6.8% TBSA (6.5-80%), and there were 3.75 operations per patient. Four had fourth-degree burns requiring finger amputations (2), flaps to cover bone (1), or a through-knee amputation (1). Ten patients were admitted to the intensive care unit, and nine patients (seven with inhalation injury) required mechanical ventilation for a mean of 23.6 ± 10.3 days. All the surviving children were discharged after a mean length of stay of 45.9 ± 8.7 days. In the first year postinjury, seven children were readmitted a total of 11 times for reconstructive surgery, wound care, or rehabilitation. Ultimately, a total of 49 children died. A review of other daycare centers

  13. ABC transporters and multidrug resistance in Aspergillus nidulans

    OpenAIRE

    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- c assette (ABC) superfamily. The ABC transporters comprise a large and multifunctional family of proteins. Besides multidrug transporters, the superfamily includes proteins involved in transmembrane transport of various substances such as ions, amino acids, peptides, sugars, vitamins, s...

  14. ABC-B transporter genes in Dirofilaria immitis

    Directory of Open Access Journals (Sweden)

    Catherine Bourguinat

    2016-08-01

    Full Text Available 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.

  15. The superintegron integrase and the cassette promoters are co-regulated in Vibrio cholerae.

    Directory of Open Access Journals (Sweden)

    Evelyne Krin

    Full Text Available Chromosome 2 of Vibrio cholerae carries a chromosomal superintegron, composed of an integrase, a cassette integration site (attI and an array of mostly promoterless gene cassettes. We determined the precise location of the promoter, Pc, which drives the transcription of the first cassettes of the V. cholerae superintegron. We found that cassette mRNA starts 65 bp upstream of the attI site, so that the inversely oriented promoters Pc and Pint (integrase promoter partly overlap, allowing for their potential co-regulation. Pint was previously shown to be induced during the SOS response and is further controlled by the catabolite repression cAMP-CRP complex. We found that cassette expression from Pc was also controlled by the cAMP-CRP complex, but is not part of the SOS regulon. Pint and Pc promoters were both found to be induced in rich medium, at high temperature, high salinity and at the end of exponential growth phase, although at very different levels and independently of sigma factor RpoS. All these results show that expression from the integrase and cassette promoters can take place at the same time, thus leading to coordinated excisions and integrations within the superintegron and potentially coupling cassette shuffling to immediate selective advantage.

  16. Flipase-mediated cassette exchange in Sf9 insect cells for stable gene expression.

    Science.gov (United States)

    Fernandes, Fabiana; Vidigal, João; Dias, Mafalda M; Prather, Kristala L J; Coroadinha, Ana S; Teixeira, Ana P; Alves, Paula M

    2012-11-01

    Site-specific DNA integration allows predictable heterologous gene expression and circumvents extensive clone screening. Herein, the establishment of a Flipase (Flp)-mediated cassette exchange system in Sf9 insect cells for targeted gene integration is described. A tagging cassette harboring a reporter dsRed gene was randomly introduced into the cell genome after screening different transfection protocols. Single-copy integration clones were then co-transfected with both Flp-containing plasmid and an EGFP-containing targeting cassette. Successful cassette exchange was suggested by emergence of G418-resistant green colonies and confirmed by PCR analysis, showing the absence of the tagging cassette and single integration of the targeting cassette in the same locus. Upon cassette exchange, uniform EGFP expression between clones derived from the same integration site was obtained. Moreover, the resulting cell clones exhibited the expression properties of the parental cell line. EGFP production titers over 40 mg/L were of the same order of magnitude as those achieved through baculovirus infection. This Sf9 master cell line constitutes a versatile and re-usable platform to produce multiple recombinant proteins for fundamental and applied research.

  17. Radiation exposure reduction by use of Kevlar cassettes in the neonatal nursery.

    Science.gov (United States)

    Herman, M W; Mak, H K; Lachman, R S

    1987-05-01

    A study was performed to determine whether the use of Kevlar cassettes in the neonatal intensive care nursery would reduce radiation exposure to patients. The radiation dose to the neonates was measured by using thermoluminescent dosimeters. In addition, the attenuation of the Kevlar cassettes and the sensitivity of the film-screen combination were compared with the previously used system. The greatest radiation reduction using a mobile X-ray unit was 27%; based on sensitivity measurements, the theoretical reduction averaged 38%. The reduction in radiation exposure resulted from reduced attenuation by the Kevlar cassette.

  18. Conserved allosteric hot spots in the transmembrane domains of cystic fibrosis transmembrane conductance regulator (CFTR) channels and multidrug resistance protein (MRP) pumps.

    Science.gov (United States)

    Wei, Shipeng; Roessler, Bryan C; Chauvet, Sylvain; Guo, Jingyu; Hartman, John L; Kirk, Kevin L

    2014-07-18

    ATP-binding cassette (ABC) transporters are an ancient family of transmembrane proteins that utilize ATPase activity to move substrates across cell membranes. The ABCC subfamily of the ABC transporters includes active drug exporters (the multidrug resistance proteins (MRPs)) and a unique ATP-gated ion channel (cystic fibrosis transmembrane conductance regulator (CFTR)). The CFTR channel shares gating principles with conventional ligand-gated ion channels, but the allosteric network that couples ATP binding at its nucleotide binding domains (NBDs) with conformational changes in its transmembrane helices (TMs) is poorly defined. It is also unclear whether the mechanisms that govern CFTR gating are conserved with the thermodynamically distinct MRPs. Here we report a new class of gain of function (GOF) mutation of a conserved proline at the base of the pore-lining TM6. Multiple substitutions of this proline promoted ATP-free CFTR activity and activation by the weak agonist, 5'-adenylyl-β,γ-imidodiphosphate (AMP-PNP). TM6 proline mutations exhibited additive GOF effects when combined with a previously reported GOF mutation located in an outer collar of TMs that surrounds the pore-lining TMs. Each TM substitution allosterically rescued the ATP sensitivity of CFTR gating when introduced into an NBD mutant with defective ATP binding. Both classes of GOF mutations also rescued defective drug export by a yeast MRP (Yor1p) with ATP binding defects in its NBDs. We conclude that the conserved TM6 proline helps set the energy barrier to both CFTR channel opening and MRP-mediated drug efflux and that CFTR channels and MRP pumps utilize similar allosteric mechanisms for coupling conformational changes in their translocation pathways to ATP binding at their NBDs.

  19. Metodologia ABC: implantação numa microempresa ABC methodology: implementation on a micro firm

    Directory of Open Access Journals (Sweden)

    Orlando Duran

    2000-08-01

    Full Text Available Este trabalho relata a implantação da metodologia de custos baseados em atividades numa microempresa do ramo metalúrgico. A proposta pretende demonstrar a viabilidade de aplicar esta técnica em empresas sem importar seu tamanho, só realizando algumas adaptações que garantam baixo investimento e curto espaço de tempo para obter os resultados. Na parte final do trabalho se realiza uma análise dos resultados obtidos verificando-se o potencial da informação gerada pela metodologia e seu uso como ferramenta de gestão.This paper presents an implementation of the activity based costing (ABC methodology in a small firm. The approach presented is intended to demonstrate the feasibility of applying the ABC methodology at any sized firm, only through few adaptations for ensuring low investments fees and speed in obtaining results and information from the system. Discussion about the results obtained during the implementation case are presented and the potential of using the information generated from the system as a managing tool is commented.

  20. Modulation of breast cancer resistance protein mediated atypical multidrug resistance using RNA interference delivered by adenovirus

    Institute of Scientific and Technical Information of China (English)

    LI Wen-tong; ZHOU Geng-yin; WANG Chun-ling; GUO Cheng-hao; SONG Xian-rang; CHI Wei-ling

    2005-01-01

    @@ Clinical multidrug resistance (MDR) of malignancies to many antineoplastic agents is the major obstacle in the successful treatment of cancer. The emergence of breast cancer resistance protein (BCRP), a member of the adenosine triphosphate (ATP) binding cassette (ABC) transporter family, has necessitated the development of antagonists. To overcome the BCRP-mediated atypical MDR, RNA interference (RNAi) delivered by adenovirus targeting BCRP mRNA was used to inhibit the atypical MDR expression by infecting MCF-7/MX100 cell lines with constructed RNAi adenovirus.

  1. Identification of multidrug resistance protein 1 (MRP1/ABCC1) as a molecular gate for cellular export of cobalamin

    DEFF Research Database (Denmark)

    Beedholm-Ebsen, Rasmus; van de Wetering, Koen; Hardlei, Tore;

    2010-01-01

    transporters by cellular gene silencing showed a role in cellular Cbl efflux of the ATP-binding cassette (ABC)-drug transporter, ABCC1, alias multidrug resistance protein 1 (MRP1), which is present in the basolateral membrane of intestinal epithelium and in other cells. The ability of MRP1 to mediate ATP...... and kidney. In contrast, Cbl accumulates in the terminal part of the intestine of these mice, suggesting a functional malabsorption because of a lower epithelial basolateral Cbl efflux. The identification of this Cbl export mechanism now allows the delineation of a coherent pathway for Cbl trafficking from...

  2. Moving out: from sterol transport to drug resistance - the ABCG subfamily of efflux pumps.

    Science.gov (United States)

    Moitra, Karobi; Silverton, Latoya; Limpert, Katy; Im, Kate; Dean, Michael

    2011-01-01

    The ATP binding cassette (ABC) proteins are typically ATP-driven transmembrane pumps that have been evolutionarily conserved from bacteria to humans. In humans these transporters are subdivided into seven subfamilies, ranging from A to G. The ABCG subfamily of transporters is the primary focus of this review. This subfamily of proteins has been conserved throughout evolution and plays a central role in several cellular processes, such as sterol homeostasis and multidrug resistance. Functional polymorphisms/mutations in some of these G-subfamily transporters have clinical consequences in humans.

  3. Searching for the fastest dynamo: laminar ABC flows.

    Science.gov (United States)

    Alexakis, Alexandros

    2011-08-01

    The growth rate of the dynamo instability as a function of the magnetic Reynolds number R(M) is investigated by means of numerical simulations for the family of the Arnold-Beltrami-Childress (ABC) flows and for two different forcing scales. For the ABC flows that are driven at the largest available length scale, it is found that, as the magnetic Reynolds number is increased: (a) The flow that results first in a dynamo is the 2 1/2-dimensional flow for which A=B and C=0 (and all permutations). (b) The second type of flow that results in a dynamo is the one for which A=B≃2C/5 (and permutations). (c) The most symmetric flow, A=B=C, is the third type of flow that results in a dynamo. (d) As R(M) is increased, the A=B=C flow stops being a dynamo and transitions from a local maximum to a third-order saddle point. (e) At larger R(M), the A=B=C flow reestablishes itself as a dynamo but remains a saddle point. (f) At the largest examined R(M), the growth rate of the 2 1/2-dimensional flows starts to decay, the A=B=C flow comes close to a local maximum again, and the flow A=B≃2C/5 (and permutations) results in the fastest dynamo with growth rate γ≃0.12 at the largest examined R(M). For the ABC flows that are driven at the second largest available length scale, it is found that (a) the 2 1/2-dimensional flows A=B,C=0 (and permutations) are again the first flows that result in a dynamo with a decreased onset. (b) The most symmetric flow, A=B=C, is the second type of flow that results in a dynamo. It is, and it remains, a local maximum. (c) At larger R(M), the flow A=B≃2C/5 (and permutations) appears as the third type of flow that results in a dynamo. As R(M) is increased, it becomes the flow with the largest growth rate. The growth rates appear to have some correlation with the Lyapunov exponents, but constructive refolding of the field lines appears equally important in determining the fastest dynamo flow.

  4. The function of integron-associated genes cassettes in Vibrio species: the tip of the iceberg

    Directory of Open Access Journals (Sweden)

    Rita A Rapa

    2013-12-01

    Full Text Available The integron is a genetic element that incorporates mobile genes termed gene cassettes into a reserved genetic site via site-specific recombination. It is best known for its role in antibiotic resistance with one type of integron, the class 1 integron, a major player in the dissemination of antibiotic resistance genes across Gram negative pathogens and commensals. However, integrons are ancient structures with over 100 classes (including class 1 present in bacteria from the broader environment. While, the class 1 integron is only one example of an integron being mobilised into the clinical environment, it is by far the most successful. Unlike clinical class 1 integrons which are largely found on plasmids, other integron classes are found on the chromosomes of bacteria and carry diverse gene cassettes indicating a non-antibiotic resistance role(s. However, there is very limited knowledge on what these alternative roles are. This is particularly relevant to Vibrio species where gene cassettes make up approximately 1-3% of their entire genome. In this review, we discuss how emphasis on class 1 integron research has resulted in a limited understanding by the wider research community on the role of integrons in the broader environment. This has the capacity to be counterproductive in solving or improving the antibiotic resistance problem into the future. Furthermore, there is still a significant lack of knowledge on how gene cassettes in Vibrio species drive adaptation and evolution. From research in V. rotiferianus DAT722, new insight on how gene cassettes affect cellular physiology offers new alternative roles for the gene cassette resource. At least a subset of gene cassettes are involved in host surface polysaccharide modification suggesting that gene cassette may be important in processes such as bacteriophage resistance, adhesion/biofilm formation, protection from grazers and bacterial aggregation.

  5. Influence of cassette design on three-dimensional perfusion culture of artificial bone.

    Science.gov (United States)

    Du, Dajiang; Ushida, Takashi; Furukawa, Katsuko S

    2015-01-01

    Media perfusion is often required to maintain cell viability within topographically complex 3-dimensional scaffold cultures. Osteoblast-seeded scaffolds for bone regeneration require robust cell proliferation and survival both within the scaffold and over the exterior for optimal osteogenic capacity. Conventional press-fitting cassettes ensure internal fluid flow through the scaffold but may restrict external flow around the scaffold, resulting in a barren (cell-free) external scaffold surface. In this study, we aimed to solve this problem by modifying the cassette structure to enhance external flow in an oscillatory perfusion culture system. Mouse osteoblast-like MC 3T3-E1 cells were seeded in porous ceramic scaffolds and incubated for 3 days either under static culture conditions or in an oscillatory perfusion bioreactor. Scaffolds were held in the bioreactor with either conventional press-fitting cassettes or cassettes with rings to separate the scaffold exterior from the internal cassette wall. The external surfaces of scaffolds maintained under static conditions were well seeded, but cells failed to grow deeply into the core, reflecting poor internal chemotransport. Alternatively, scaffolds cultured by perfusion with press-fitting cassettes had poor cell viability at the cassette-external scaffold surface interface, but cells were widely distributed within the scaffold core. Scaffolds cultured using the modified cassettes with 1 or 2 rings exhibited uniformly distributed living cells throughout the internal pores and over the entire external surface, possibly because of the improved medium flow over the scaffold surface. This modified oscillatory perfusion culture system may facilitate the production of engineered bone with superior osteogenic capacity for grafting.

  6. Independent activity of the homologous small regulatory RNAs AbcR1 and AbcR2 in the legume symbiont Sinorhizobium meliloti.

    Directory of Open Access Journals (Sweden)

    Omar Torres-Quesada

    Full Text Available The legume symbiont Sinorhizobium meliloti expresses a plethora of small noncoding RNAs (sRNAs whose function is mostly unknown. Here, we have functionally characterized two tandemly encoded S. meliloti Rm1021 sRNAs that are similar in sequence and structure. Homologous sRNAs (designated AbcR1 and AbcR2 have been shown to regulate several ABC transporters in the related α-proteobacteria Agrobacterium tumefaciens and Brucella abortus. In Rm1021, AbcR1 and AbcR2 exhibit divergent unlinked regulation and are stabilized by the RNA chaperone Hfq. AbcR1 is transcribed in actively dividing bacteria, either in culture, rhizosphere or within the invasion zone of mature alfalfa nodules. Conversely, AbcR2 expression is induced upon entry into stationary phase and under abiotic stress. Only deletion of AbcR1 resulted into a discrete growth delay in rich medium, but both are dispensable for symbiosis. Periplasmic proteome profiling revealed down-regulation of the branched-chain amino acid binding protein LivK by AbcR1, but not by AbcR2. A double-plasmid reporter assay confirmed the predicted specific targeting of the 5'-untranslated region of the livK mRNA by AbcR1 in vivo. Our findings provide evidences of independent regulatory functions of these sRNAs, probably to fine-tune nutrient uptake in free-living and undifferentiated symbiotic rhizobia.

  7. Integron gene cassettes: a repository of novel protein folds with distinct interaction sites.

    Directory of Open Access Journals (Sweden)

    Visaahini Sureshan

    Full Text Available Mobile gene cassettes captured within integron arrays encompass a vast and diverse pool of genetic novelty. In most cases, functional annotation of gene cassettes directly recovered by cassette-PCR is obscured by their characteristically high sequence novelty. This inhibits identification of those specific functions or biological features that might constitute preferential factors for lateral gene transfer via the integron system. A structural genomics approach incorporating x-ray crystallography has been utilised on a selection of cassettes to investigate evolutionary relationships hidden at the sequence level. Gene cassettes were accessed from marine sediments (pristine and contaminated sites, as well as a range of Vibrio spp. We present six crystal structures, a remarkably high proportion of our survey of soluble proteins, which were found to possess novel folds. These entirely new structures are diverse, encompassing all-α, α+β and α/β fold classes, and many contain clear binding pocket features for small molecule substrates. The new structures emphasise the large repertoire of protein families encoded within the integron cassette metagenome and which remain to be characterised. Oligomeric association is a notable recurring property common to these new integron-derived proteins. In some cases, the protein-protein contact sites utilised in homomeric assembly could instead form suitable contact points for heterogeneous regulator/activator proteins or domains. Such functional features are ideal for a flexible molecular componentry needed to ensure responsive and adaptive bacterial functions.

  8. Cassette loaded with a resilient packing to connect socket ends on the sea bed

    Energy Technology Data Exchange (ETDEWEB)

    Tuson, S.P.R.

    1983-06-08

    A cassette loaded with a resilient packing is used to connect a pipe on the sea bed to one end of a hollow shaft forming part of the crosspiece of a cardan joint at the base of an articulated columns mounted on the sea bed. The resilient packing comprises a stack of rubber rings and metallic washers disposed between end rings and capable of being derformed in torsion, the packing in use being compressed between an abutment on the end of the hollow shaft in the cardan joint and an abutment on the adjacent end of the pipe. The cassette comprises a tubular body which can be fitted in or removed from a housing for a bearing of the cardan joint, the end rings of the packing projecting through the opposite ends of the tubular body of the cassette. The cassette is fitted with jacks for compressing the packing, and wedges for retaining the packing in a compressed state until the cassette is fitted in the bearing housing, whereupon the jacks are again operated to compress further the packing and enable the wedges to be removed. Release of the jacks then allows the packing to expand within the cassette and engage the ends of the packing against the ends of the hollow shaft and pipe so as to form a connection therebetween. 2 drawings.

  9. 基于ABC-PCNN模型的图像分割%Image segmentation based on ABC-PCNN model

    Institute of Scientific and Technical Information of China (English)

    廖传柱; 张旦; 江铭炎

    2014-01-01

    为使标准脉冲耦合神经网络( Pulse coupled neural network,PCNN)模型在图像分割中能够自适应地调整模型参数与全局阈值,提高分割效果,该文提出一种基于人工蜂群( Artificial bee colony,ABC)算法改进的自适应PCNN 模型,即人工蜂群算法-脉冲耦合神经网络( ABC-PCNN)模型;提出了改进后的乘积型交叉熵函数,并利用ABC算法将此函数作为其适应度函数优化输出其连接系数和阈值。采用Lena图像和血细胞图像评估PCNN模型和ABC-PCNN模型的性能。实验结果表明:ABC-PCNN模型对图像的自适应分割效果优于PCNN模型。针对血细胞分割图像中存在的重叠区域,该文结合角点和质点坐标定位重叠区域的二次分割线得到最终分割图像,所提算法高效且能得到较好的分割结果。%In order to adjust the model parameters and the global threshold for image segmentation, an improved pulse coupled neural network ( PCNN ) model based on artificial bee colony ( ABC ) algorithm,namely ABC-PCNN,is proposed here. It combines a new criterion of product cross entropy with the standard simplified PCNN model. The product cross entropy is used as the fitness function to optimize the connection output coefficient and threshold value by the ABC algorithm. Lena image and blood cell image are used to evaluate the PCNN model and the ABC-PCNN model respectively. The experimental results show that the adaptive image segmentation by the ABC-PCNN model outperforms that by the PCNN model. As the overlapping areas need secondary segmentation in the segmented blood cell image,corners and center coordinates are used to locate the dividing line and to get the final image segmentation. The method proposed here is effective and can obtain better segmentation results.

  10. Observation of the ABC effect and final-state isospin

    Science.gov (United States)

    Doroshkevich, E. A.; Bashkanov, M. A.; Clement, H.; Perez del Rio, E.; Pricking, A.; Skorodko, T. Yu.; Wagner, G. J.

    2014-07-01

    Despite the number of inclusive measurements of the pionic fusion reactions, the nature of the ABC effect discovered in 1960 was not completely established. Exclusive measurements of the doublepion-production reactions leading to either fused d, 3He and 4He nuclear final states or pp pairs are analyzed. A significant ABC effect—enhancement in the region of low ππ mass—is found only in the isoscalar ππ channel while in the isovector channels it is small or absent. For the reaction with isovector pp final state an ABC effect was not observed even at the special kinematic conditions to reproduce a quasi-bound two-proton state. The total cross sections for the d and 4He fusion reactions show similar resonance-like energy dependence.

  11. 如何实现ABC/ABM与ERP的集成

    Institute of Scientific and Technical Information of China (English)

    伍冬凤

    2006-01-01

    上世纪70年代之后,高新技术的蓬勃发展和广泛应用,为作业成本计算(Activity-Based Cost,ABC)和作业管理(Activity Based Management,ABM)的出现奠定了基础.本文以成本管理理论为起点,结合分析企业资源计划(Enterprise Resources Planning,ERP)系统基本原理与成本管理功能,据以提出一种将ABC/ABM与ERP集成的策略,并描述了ABC/ABM模块主要数据维护流程图.

  12. Chondroitinase ABC improves recovery of long sciatic nerve defects

    Institute of Scientific and Technical Information of China (English)

    Hailong Yu; Liangbi Xiang; Wenjing Xu; Bin Zhao; Yu Wang; Jiang Peng; Shibi Lu

    2012-01-01

    Sciatic nerves from allogeneic Sprague-Dawley rats were pretreated with chondroitinase ABC and were used to bridge damaged sciatic nerves in Wistar rats. Chondroitin sulfate proteoglycans were removed from the chemically extracted acellular nerves. At 3 months after grafting, the footplate pinch test result was positive in the Wistar rats. Autotomy scores decreased, and increased muscular contraction tension appeared when triceps surae muscles were stimulated. In addition, the recovery rate of wet triceps surae muscle weight increased, and the distal segment of the chondroitinase ABC-treated graft exhibited Schwann cells next to the nerve fibers. These results suggested that chondroitinase ABC pretreatment enhanced repair of long nerve defects via acellular nerve grafting.

  13. Investigating the compatibility of the biocontrol agent Clonostachys rosea IK726 with prodigiosin-producing Serratia rubidaea S55 and phenazine-producing Pseudomonas chlororaphis ToZa7.

    Science.gov (United States)

    Kamou, Nathalie N; Dubey, Mukesh; Tzelepis, Georgios; Menexes, Georgios; Papadakis, Emmanouil N; Karlsson, Magnus; Lagopodi, Anastasia L; Jensen, Dan Funck

    2016-05-01

    This study was carried out to assess the compatibility of the biocontrol fungus Clonostachys rosea IK726 with the phenazine-producing Pseudomonas chlororaphis ToZa7 or with the prodigiosin-producing Serratia rubidaea S55 against Fusarium oxysporum f. sp. radicis-lycopersici. The pathogen was inhibited by both strains in vitro, whereas C. rosea displayed high tolerance to S. rubidaea but not to P. chlororaphis. We hypothesized that this could be attributed to the ATP-binding cassette (ABC) proteins. The results of the reverse transcription quantitative PCR showed an induction of seven genes (abcB1, abcB20, abcB26, abcC12, abcC12, abcG8 and abcG25) from subfamilies B, C and G. In planta experiments showed a significant reduction in foot and root rot on tomato plants inoculated with C. rosea and P. chlororaphis. This study demonstrates the potential for combining different biocontrol agents and suggests an involvement of ABC transporters in secondary metabolite tolerance in C. rosea.

  14. Circumvention of multi-drug resistance of cancer cells by Chinese herbal medicines

    Directory of Open Access Journals (Sweden)

    Lin Ge

    2010-07-01

    Full Text Available Abstract Multi-drug resistance (MDR of cancer cells severely limits therapeutic outcomes. A proposed mechanism for MDR involves the efflux of anti-cancer drugs from cancer cells, primarily mediated by ATP-binding cassette (ABC membrane transporters including P-glycoprotein. This article reviews the recent progress of using active ingredients, extracts and formulae from Chinese medicine (CM in circumventing ABC transporters-mediated MDR. Among the ABC transporters, Pgp is the most extensively studied for its role in MDR reversal effects. While other MDR reversal mechanisms remain unclear, Pgp inhibition is a criterion for further mechanistic study. More mechanistic studies are needed to fully establish the pharmacological effects of potential MDR reversing agents.

  15. Optimization of the drug management by the ABC-VEN method%ABC-VEN法优化药品管理

    Institute of Scientific and Technical Information of China (English)

    陶萍

    2010-01-01

    目的 优化药品库存,提高药品管理水平,节约药品管理成本.方法 使用ABC-VEN法对药品进行科学分类,根据分类采用不同的库存管理.结果 使用ABC-VEN法对药品实行优化管理,保证了临床药品供应,压缩了药品库存,提高了药品管理效率.结论 运用ABC-VEN法对药品进行优化管理切实可行,为医院药品管理提供了一定的理论和实践参考.

  16. Ground Testing of the EMCS Seed Cassette for Biocompatibility with the Tardigrade, Hypsibius dujardini

    Science.gov (United States)

    Reinsch, Sigrid; Myers, Zachary Alan; DeSimone, Julia Carol; Freeman, John L.; Steele, Marianne K.; Sun, Gwo-Shing; Heathcote, David

    2014-01-01

    The European Modular Cultivation System, EMCS, was developed by ESA for plant experiments. We performed ground testing to determine whether ARC EMCS seed cassettes could be adapted for use with tardigrades for future spaceflight experiments. Tardigrades (water bears) are small invertebrates that enter the tun state in response to desiccation or other environmental stresses. Tardigrade tuns have suspended metabolism and have been shown to be survive exposure to space vacuum, high pressure, temperature and other stresses. For spaceflight experiments using the EMCS, the organisms ideally must be able to survive desiccation and storage in the cassette at ambient temperature for several weeks prior to the initiation of the experiment by the infusion of water to the cassette during spaceflight. The ability of tardigrades to survive extremes by entering the tun state make them ideal candidates for growth experiments in the EMCS cassettes. The growth substratum in the cassettes is a gridded polyether sulfone (PES) membrane. A blotter beneath the PES membrane contains dried growth medium. The goals of our study were to (1) determine whether tardigrades survive and reproduce on PES membranes, (2) develop a consistent method for dehydration of the tardigrades with high recovery rates upon rehydration, (3) to determine an appropriate food source for the tardigrades that can also be dehydrated/rehydrated and (4) successful mock rehydration experiment in cassettes with appropriate food source. We present results that show successful multigenerational growth of tardigrades on PES membranes with a variety of wet food sources. We have successfully performed a mock rehydration with tardigrades and at least one candidate food, protonema of the moss Polytrichum, that supports multigenerational growth and whose spores germinate quickly enough to match tardigrade feeding patterns post rehydration. Our results indicate that experiments on the ISS using the tardigrade, Hypsibius dujardini

  17. On Application of ABC Approach in Management of Agri- scientific Research Cost

    Institute of Scientific and Technical Information of China (English)

    Liangchun; ZHA

    2014-01-01

    This paper firstly introduced theoretical background of the Activity-Based Costing(ABC). Then,it analyzed necessity,extension resistance and difficulty of ABC approach in agri-scientific research institutions. Finally,it came up with some recommendations for scientifically learning and steadily promoting ABC method in agri-scientific research field.

  18. ABCs of Being Smart... G Is for Gifted!

    Science.gov (United States)

    Foster, Joanne

    2012-01-01

    Giftedness can generate speculation, misconceptions, expectations, pride, innuendo, apprehension, puzzlement--and the list goes on. What does it mean to be a gifted learner? In this installment of the series "ABCs of Being Smart," the author grapples with the term gifted, giving a glimpse into giftedness, along with some general guidelines for…

  19. I am Calm: Towards a Psychoneurological Evaluation of ABC Ringtones

    Directory of Open Access Journals (Sweden)

    John N.A. Brown

    2015-10-01

    Full Text Available Anthropology-Based Computing (ABC suggests that socio-cultural, neurological, and physiological parameters of normal human interaction with the world can be applied to current technology in order to improve Human-Computer Interaction (HCI. To challenge this theory, we hypothesized smartphone ringtones that could be targeted to specific people in a manner that would inform them without disturbing their work or the work of others. In this paper we report the quantitative data from the first formal trials of these ‘ABC ringtones’. Beta Wave activity patterns were recorded in the brains of 10 participants exposed to 5 different ringtones at three different volumes while they were focused on performing a typing test in a noisy environment. Our preliminary findings seem to show that the ABC ringtones - at a volume too low to be consciously heard - triggered a response in the pre-attentive part of the brain, and that the embedded information was transferred to the attentive part of the brain by an internal mechanism that did not disrupt the work being done in the typing task. We propose that these results provide preliminary evidence for the ABC model of HCI and its explanation of the centering mechanism that is requisite if Peripheral Interaction is to be applied in changing Ubiquitous Computing into Calm Technology.

  20. 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,

  1. Dynamics of 'abc' and 'qd' constant parameters induction generator model

    DEFF Research Database (Denmark)

    Fajardo-R, L.A.; Medina, A.; Iov, F.

    2009-01-01

    In this paper, parametric sensibility effects on dynamics of the induction generator in the presence of local perturbations are investigated. The study is conducted in a 3x2 MW wind park dealing with abc, qd0 and qd reduced order, induction generator model respectively, and with fluxes as state v...

  2. Selections from the ABC 2012 Annual Convention, Honolulu, Hawaii

    Science.gov (United States)

    Whalen, D. Joel

    2013-01-01

    The 13 Favorite Assignments featured here were presented at the 2012 Association for Business Communication (ABC) Annual Convention, Honolulu, Hawaii. A variety of learning objectives are featured, including the following: enhancing resume's visual impact, interpersonal skills, social media, team building, web design, community service…

  3. 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 capacity to transport a broad variety of substrates, ranging fr

  4. Dissociations among ABA, ABC, and AAB Recovery Effects

    Science.gov (United States)

    Ungor, Metin; Lachnit, Harald

    2008-01-01

    In a human predictive learning experiment, the strengths of ABA, ABC, and AAB recovery effects after discrimination reversal learning were compared. Initially, a discrimination between two stimuli (X+, Y-) was trained in Context A. During Phase 2, participants received discrimination reversal training (X-, Y+) either in Context A (Group AAB) or in…

  5. Effect of attC structure on cassette excision by integron integrases

    Directory of Open Access Journals (Sweden)

    Larouche André

    2011-02-01

    Full Text Available Abstract Background Integrons are genetic elements able to integrate and disseminate genes as cassettes by a site-specific recombination mechanism. These elements contain a gene coding for an integrase that carries out recombination by interacting with two different target sites; the attI site in cis with the integrase and the palindromic attC site of a gene cassette. Integron integrases (IntIs bind specifically to the bottom strand of attC sites. The extrahelical bases resulting from folding of attC bottom strands are important for the recognition by integrases. These enzymes are directly involved in the accumulation and formation of new cassette arrangements in the variable region of integrons. Thus, it is important to better understand interactions between IntIs and their substrates. Results We compared the ability of five IntIs to carry out excision of several cassettes flanked by different attC sites. The results showed that for most cassettes, IntI1 was the most active integrase. However, IntI2*179E and SonIntIA could easily excise cassettes containing the attCdfrA1 site located upstream, whereas IntI1 and IntI3 had only a weak excision activity for these cassettes. Analysis of the secondary structure adopted by the bottom strand of attCdfrA1 has shown that the identity of the extrahelical bases and the distance between them (A-N7-8-C differ from those of attCs contained in the cassettes most easily excisable by IntI1 (T-N6-G. We used the attCdfrA1 site upstream of the sat2 gene cassette as a template and varied the identity and spacing between the extrahelical bases in order to determine how these modifications influence the ability of IntI1, IntI2*179E, IntI3 and SonIntIA to excise cassettes. Our results show that IntI1 is more efficient in cassette excision using T-N6-G or T-N6-C attCs while IntI3 recognizes only a limited range of attCs. IntI2*179E and SonIntIA are more tolerant of changes to the identity and spacing of extrahelical

  6. The effects of ABCG5/G8 polymorphisms on HDL-cholesterol concentrations depend on ABCA1 genetic variants in the Boston Puerto Rican health study

    Science.gov (United States)

    Background and aims: ATP-binding cassette transporters G5/G8 (ABCG5/G8) are associated with HDL-C concentrations. To assess whether the effect of ABCG5/G8 genetic variants on HDL-C concentrations is dependent on ATP-binding cassette transporters A1 (ABCA1), we studied potential interactions between ...

  7. NCBI nr-aa BLAST: CBRC-TTRU-01-1060 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-1060 ref|XP_002523691.1| ATP-binding cassette transporter, putative [Ricinus... communis] gb|EEF38631.1| ATP-binding cassette transporter, putative [Ricinus communis] XP_002523691.1 0.012 25% ...

  8. NCBI nr-aa BLAST: CBRC-MLUC-01-0864 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-MLUC-01-0864 ref|XP_002522797.1| ATP-binding cassette transporter, putative [Ricinus... communis] gb|EEF39648.1| ATP-binding cassette transporter, putative [Ricinus communis] XP_002522797.1 1.3 24% ...

  9. A Compute Environment of ABC95 Array Computer Based on Multi-FPGA Chip

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    ABC95 array computer is a multi-function network's computer based on FPGA technology, The multi-function network supports processors conflict-free access data from memory and supports processors access data from processors based on enhanced MESH network.ABC95 instruction's system includes control instructions, scalar instructions, vectors instructions.Mostly net-work instructions are introduced.A programming environment of ABC95 array computer assemble language is designed.A programming environment of ABC95 array computer for VC++ is advanced.It includes load function of ABC95 array computer program and data, store function, run function and so on.Specially, The data type of ABC95 array computer conflict-free access is defined.The results show that these technologies can develop programmer of ABC95 array computer effectively.

  10. Analysis of the effect of the bovine adenosine triphosphate-binding cassette transporter G2 single nucleotide polymorphism Y581S on transcellular transport of veterinary drugs using new cell culture models.

    Science.gov (United States)

    Real, R; González-Lobato, L; Baro, M F; Valbuena, S; de la Fuente, A; Prieto, J G; Alvarez, A I; Marques, M M; Merino, G

    2011-12-01

    In commercial dairy production, the risk of drug residues and environmental pollutants in milk from ruminants has become an outstanding problem. One of the main determinants of active drug secretion into milk is the ATP-binding cassette transporter G2/breast cancer resistance protein (ABCG2/BCRP). It is located in several organs associated with drug absorption, metabolism, and excretion, and its expression is highly induced during lactation in the mammary gland of ruminants, mice, and humans. As a consequence, potential contamination of milk could expose suckling infants to xenotoxins. In cows, a SNP for this protein affecting quality and quantity of milk production has been described previously (Y581S). In this study, our main purpose was to determine whether this polymorphism has an effect on transcellular transport of veterinary drugs because this could alter substrate pharmacokinetics and milk residues. We stably expressed the wild-type bovine ABCG2 and the Y581S variant in Madin-Darby canine kidney epithelial cells (MDCKII) and MEF3.8 cell lines generating cell models in which the functionality of the bovine transporter could be addressed. Functional studies confirmed the greater functional activity in mitoxantrone accumulation assays for the Y581S variant with a greater relative V(MAX) value (P = 0.040) and showed for the first time that the Y581S variant presents greater transcellular transport of the model ABCG2 substrate nitrofurantoin (P = 0.024) and of 3 veterinary antibiotics, the fluoroquinolone agents enrofloxacin (P = 0.035), danofloxacin (P = 0.001), and difloxacin (P = 0.008), identified as new substrates of the bovine ABCG2. In addition, the inhibitory effect of the macrocyclic lactone ivermectin on the activity of wild-type bovine ABCG2 and the Y581S variant was also confirmed, showing a greater inhibitory potency on the wild-type protein at all the concentrations tested (5 μM, P = 0.017; 10 μM, P = 0.001; 25 μM, P = 0.008; and 50 μM, P = 0

  11. Control model for compressible cake filtration of green liquor in cassette filter

    OpenAIRE

    Bornefelt, Kajsa

    2006-01-01

    In the closed chemical recovery cycle in the sulphate pulp mill it is important to remove non-process elements. This is done by clarification of the green liquor, either in clarifiers or in filters. This project focuses on a cassette filter developed by Kvaerner Pulping AB. The cassette filter is semi-continuous and the aim of the project was to model the filter in order to be able to control cycle time and feed towards optimization of the capacity. The green liquor sludge forms a compressibl...

  12. Construction of New Campylobacter Cloning Vectors and a New Mutational Cat Cassette

    Science.gov (United States)

    1993-01-01

    mutational cat cassette PE - 61102A PR - 3M161102 6. AUTHOR(S) TA - BS13AK Yao R, Aim RA, Trust TJ, Guerry P WU- 1291 7. PERFORMING ORGANIZATION NAME(S) AND...mutational cat cassette %~ccesion For (Site-specific mutagenesis; recombinant DNA; multiple cloning site; PCR; shuttle vectors) NTIS CRA&I OTIC TAB E...incompatibility plasmids can mobilize shuttle vectors containing E. coi and C. coi plasmid Systems of experimental genetics are in the early stages replicons

  13. 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

    ... Surface Transportation Board ABC & D Recycling, Inc.--Lease and Operation Exemption--a Line of Railroad in Ware, MA ABC & D Recycling, Inc. (ABC & D), a noncarrier, has filed a verified notice of exemption... operation of this trackage in FD 35356, ABC & D Recycling, Inc.--Lease and Operation Exemption--a Line...

  14. IMPLEMENTATION OF THE ABC COSTING IN A SERVICES PROVIDER COMPANY

    Directory of Open Access Journals (Sweden)

    Luiz Ricardo Aguena Jacintho Gil de Castro

    2012-12-01

    Full Text Available This paper describes the implementation of the Activity-Based Cost (ABC method in a company of taxes and accounting services and outlines the positive and negative aspects encountered during implementation. It should be taken into account that this work has been developed in the fiscal area of cost verification. Bibliographical references, internal company documents and interviews with industry officials and the administrator responsible for the company were used. In the evolving of operations, the costs of the fiscal area and their main activities have been described monthly and through this information, drivers have been developed and the ABC (Activity-Based Costing method has been adopted. With the implementation it became clear that the system provides better visualization for the decision making process, it also provided learning for the company, so that the method should be used for an undetermined period of time.

  15. Ensemble inequivalence: Landau theory and the ABC model

    Science.gov (United States)

    Cohen, O.; Mukamel, D.

    2012-12-01

    It is well known that systems with long-range interactions may exhibit different phase diagrams when studied within two different ensembles. In many of the previously studied examples of ensemble inequivalence, the phase diagrams differ only when the transition in one of the ensembles is first order. By contrast, in a recent study of a generalized ABC model, the canonical and grand-canonical ensembles of the model were shown to differ even when they both exhibit a continuous transition. Here we show that the order of the transition where ensemble inequivalence may occur is related to the symmetry properties of the order parameter associated with the transition. This is done by analyzing the Landau expansion of a generic model with long-range interactions. The conclusions drawn from the generic analysis are demonstrated for the ABC model by explicit calculation of its Landau expansion.

  16. ABC Effect in Double-Pionic Fusion - a New Resonance?

    Science.gov (United States)

    Pricking, A.; Bashkanov, M.; Clement, H.; Doroshkevich, E.; Perez del Rio, E.; Skorodko, T.; Wagner, G. J.

    2012-12-01

    ABC effect, an intriguing low-mass enhancement in the ππ invariant mass spectrum — known since more than 50 years from inclusive measurements of double-pionic fusion reactions — is reexamined. To this end exclusive and kinematically complete high-statistics experiments of the fusion reactions to d, 3He and 4He have been carried out with WASA at COSY. These measurements cover the full energy region, where the ABC effect has been observed previously. They also complement the systematic measurements of nucleon-nucleon induced two-pion production. An isospin decomposition of all three basic double-pionic fusion reactions leading to the deuteron uniquely shows that solely the isoscalar reaction part exhibits the ABC effect tightly correlated with a narrow resonance structure in the total cross section. The peak energy of the resonance structure is about 90 MeV below the nominal ΔΔ threshold of 2 mΔ and its width of only 70 MeV is much less than the 2 ГΔ expected from the conventional t-channel ΔΔ process. Based on angular distributions the quantum numbers I(JP) = 0(3+) have been assigned. In the double-pionic fusion reaction dd→4Heπ0π0 again the ABC effect is observed to be correlated with the appearance of a resonance-like structure in the total cross section at the same excess energy. From this we conclude that this resonance structure obviously is strong enough to survive even in nuclei.

  17. The ABC of Simulation Estimation with Auxiliary Statistics

    OpenAIRE

    Forneron, Jean-Jacques; Ng, Serena

    2015-01-01

    The frequentist method of simulated minimum distance (SMD) is widely used in economics to estimate complex models with an intractable likelihood. In other disciplines, a Bayesian approach known as Approximate Bayesian Computation (ABC) is far more popular. This paper connects these two seemingly related approaches to likelihood-free estimation by means of a Reverse Sampler that uses both optimization and importance weighting to target the posterior distribution. Its hybrid features enable us ...

  18. Goethe and the ABC model of flower development.

    Science.gov (United States)

    Coen, E

    2001-06-01

    About 10 years ago, the ABC model for the genetic control of flower development was proposed. This model was initially based on the analysis of mutant flowers but has subsequently been confirmed by molecular analysis. This paper describes the 200-year history behind this model, from the late 18th century when Goethe arrived at his idea of plant metamorphosis, to the genetic studies on flower mutants carried out on Arabidopsis and Antirrhinum in the late 20th century.

  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. A fluorescent cassette-based strategy for engineering multiple domain fusion proteins

    Directory of Open Access Journals (Sweden)

    Khorchid Ahmad

    2003-07-01

    Full Text Available Abstract Background The engineering of fusion proteins has become increasingly important and most recently has formed the basis of many biosensors, protein purification systems, and classes of new drugs. Currently, most fusion proteins consist of three or fewer domains, however, more sophisticated designs could easily involve three or more domains. Using traditional subcloning strategies, this requires micromanagement of restriction enzymes sites that results in complex workaround solutions, if any at all. Results Therefore, to aid in the efficient construction of fusion proteins involving multiple domains, we have created a new expression vector that allows us to rapidly generate a library of cassettes. Cassettes have a standard vector structure based on four specific restriction endonuclease sites and using a subtle property of blunt or compatible cohesive end restriction enzymes, they can be fused in any order and number of times. Furthermore, the insertion of PCR products into our expression vector or the recombination of cassettes can be dramatically simplified by screening for the presence or absence of fluorescence. Conclusions Finally, the utility of this new strategy was demonstrated by the creation of basic cassettes for protein targeting to subcellular organelles and for protein purification using multiple affinity tags.

  1. amdSYM, a new dominant recyclable marker cassette for Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Solis-Escalante, D.; Kuijpers, N.G.A.; Bongaerts, N.; Bolat, I.; Bosman, L.; Pronk, J.T.; Daran, J.M.; Daran-Lapujade, P.A.S.

    2012-01-01

    Despite the large collection of selectable marker genes available for Saccharomyces cerevisiae, marker availability can still present a hurdle when dozens of genetic manipulations are required. Recyclable markers, counterselectable cassettes that can be removed from the targeted genome after use, ar

  2. Expression of heterologous genes from an IRES translational cassette in replication competent murine leukemia virus vectors

    DEFF Research Database (Denmark)

    Jespersen, Thomas; Duch, Mogens R.; Carrasco, M L;

    1999-01-01

    of spliced env mRNA for the SL3-3 derived vector relative to the Akv derived vectors, seemingly contributing to its low replication capacity. The EGFP expressing Akv-MLV was genetically stable for multiple rounds of infection; marker-cassette deletion revertants appeared after several replication rounds...

  3. Transgene organisation in potato after particle bombardment-mediated (co-) transformation using plasmids and gene cassettes

    NARCIS (Netherlands)

    Romano, A.; Raemakers, C.J.J.M.; Bernardi, J.; Visser, R.G.F.; Mooibroek, A.

    2003-01-01

    Protocols for efficient co-transformation of potato internodes with genes contained in separate plasmids or gene cassettes (i.e., linear PCR fragments comprising a promoter-gene-terminator) using particle bombardment were established. Twenty-eight out of 62 (45%) and 11 out of 65 (17%) plants transf

  4. Trinucleotide cassettes increase diversity of T7 phage-displayed peptide library

    Directory of Open Access Journals (Sweden)

    McMahon James B

    2007-10-01

    Full Text Available Abstract Background Amino acid sequence diversity is introduced into a phage-displayed peptide library by randomizing library oligonucleotide DNA. We recently evaluated the diversity of peptide libraries displayed on T7 lytic phage and M13 filamentous phage and showed that T7 phage can display a more diverse amino acid sequence repertoire due to differing processes of viral morphogenesis. Methods In this study, we evaluated and compared the diversity of a 12-mer T7 phage-displayed peptide library randomized using codon-corrected trinucleotide cassettes with a T7 and an M13 12-mer phage-displayed peptide library constructed using the degenerate codon randomization method. Results We herein demonstrate that the combination of trinucleotide cassette amino acid codon randomization and T7 phage display construction methods resulted in a significant enhancement to the functional diversity of a 12-mer peptide library. This novel library exhibited superior amino acid uniformity and order-of-magnitude increases in amino acid sequence diversity as compared to degenerate codon randomized peptide libraries. Comparative analyses of the biophysical characteristics of the 12-mer peptide libraries revealed the trinucleotide cassette-randomized library to be a unique resource. Conclusion The combination of T7 phage display and trinucleotide cassette randomization resulted in a novel resource for the potential isolation of binding peptides for new and previously studied molecular targets.

  5. Identification of a novel streptococcal gene cassette mediating SOS mutagenesis in Streptococcus uberis

    NARCIS (Netherlands)

    Varhimo, Emilia; Savijoki, Kirsi; Jalava, Jari; Kuipers, Oscar P.; Varmanen, Pekka

    2007-01-01

    Streptococci have been considered to lack the classical SOS response, defined by increased mutation after UV exposure and regulation by LexA. Here we report the identification of a potential self-regulated SOS mutagenesis gene cassette in the Streptococcaceae family. Exposure to UV light was found t

  6. Temperature variations around medication cassette and carry bag in routine use of epoprostenol administration in healthy volunteers.

    Directory of Open Access Journals (Sweden)

    Yuichi Tamura

    Full Text Available BACKGROUND: According to several treatment guidelines, epoprostenol is an important treatment option for pulmonary arterial hypertension. However, the pharmacokinetic characteristics and poor stability of epoprostenol at room temperature make its administration challenging. We therefore studied temperature fluctuations between the drug administration cassette and atmosphere to promote the safe use of epoprostenol. METHODS AND FINDINGS: Five healthy volunteers carried a portable intravenous infusion pump attached to a medication cassette containing saline in a bag during their ordinary activities over 16 days during which the mean atmospheric temperature was 29.6 ± 1.5°C. The temperature around the medication cassette was not less than 25°C on any occasion, and the mean period over 24 h during which the temperature around the cassette exceeded 35°C and 40°C was 96.9 ± 156.4 min and 24.4 ± 77.3 min, respectively. Significant correlations were observed between the temperatures outside the bag and around the cassette, as well as between temperatures around the cassette and of the saline solution in the cassette (r = 0.9258 and 0.8276, respectively. There were no differences in the temperatures outside the bag or around the cassette with respect to the bag material. CONCLUSIONS: Temperatures around a medication cassette and outside the bag containing the medication increase with sunlight exposure. The temperature around cassettes used for administering epoprostenol must therefore be kept low for as long as possible during hot summer conditions to maintain the drug stability.

  7. Utilizing ARC EMCS Seedling Cassettes as Highly Versatile Miniature Growth Chambers for Model Organism Experiments

    Science.gov (United States)

    Freeman, John L.; Steele, Marianne K.; Sun, Gwo-Shing; Heathcote, David; Reinsch, S.; DeSimone, Julia C.; Myers, Zachary A.

    2014-01-01

    The aim of our ground testing was to demonstrate the capability of safely putting specific model organisms into dehydrated stasis, and to later rehydrate and successfully grow them inside flight proven ARC EMCS seedling cassettes. The ARC EMCS seedling cassettes were originally developed to support seedling growth during space flight. The seeds are attached to a solid substrate, launched dry, and then rehydrated in a small volume of media on orbit to initiate the experiment. We hypothesized that the same seedling cassettes should be capable of acting as culture chambers for a wide range of organisms with minimal or no modification. The ability to safely preserve live organisms in a dehydrated state allows for on orbit experiments to be conducted at the best time for crew operations and more importantly provides a tightly controlled physiologically relevant growth experiment with specific environmental parameters. Thus, we performed a series of ground tests that involved growing the organisms, preparing them for dehydration on gridded Polyether Sulfone (PES) membranes, dry storage at ambient temperatures for varying periods of time, followed by rehydration. Inside the culture cassettes, the PES membranes were mounted above blotters containing dehydrated growth media. These were mounted on stainless steel bases and sealed with plastic covers that have permeable membrane covered ports for gas exchange. The results showed we were able to demonstrate acceptable normal growth of C.elegans (nematodes), E.coli (bacteria), S.cerevisiae (yeast), Polytrichum (moss) spores and protonemata, C.thalictroides (fern), D.discoideum (amoeba), and H.dujardini (tardigrades). All organisms showed acceptable growth and rehydration in both petri dishes and culture cassettes initially, and after various time lengths of dehydration. At the end of on orbit ISS European Modular Cultivation System experiments the cassettes could be frozen at ultra-low temperatures, refrigerated, or chemically

  8. NCBI nr-aa BLAST: CBRC-OLAT-26-0102 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-OLAT-26-0102 ref|YP_634760.1| molybdate ABC transporter, ATP-binding protein [...Myxococcus xanthus DK 1622] gb|ABF91211.1| molybdate ABC transporter, ATP-binding protein [Myxococcus xanthus DK 1622] YP_634760.1 0.26 28% ...

  9. NCBI nr-aa BLAST: CBRC-DRER-26-0282 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DRER-26-0282 ref|NP_325897.1| ABC TRANSPORTER ATP-BINDING PROTEIN [Mycoplasma ...pulmonis UAB CTIP] emb|CAC13239.1| ABC TRANSPORTER ATP-BINDING PROTEIN [Mycoplasma pulmonis] NP_325897.1 0.20 24% ...

  10. NCBI nr-aa BLAST: CBRC-CINT-01-0025 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CINT-01-0025 ref|NP_692020.1| ABC transporter ATP-binding protein [Oceanobacil...lus iheyensis HTE831] dbj|BAC13055.1| ABC transporter ATP-binding protein [Oceanobacillus iheyensis HTE831] NP_692020.1 0.013 24% ...

  11. NCBI nr-aa BLAST: CBRC-CINT-01-0024 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CINT-01-0024 ref|NP_692020.1| ABC transporter ATP-binding protein [Oceanobacil...lus iheyensis HTE831] dbj|BAC13055.1| ABC transporter ATP-binding protein [Oceanobacillus iheyensis HTE831] NP_692020.1 0.008 24% ...

  12. NCBI nr-aa BLAST: CBRC-CINT-01-0088 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CINT-01-0088 ref|ZP_00997731.1| ABC transporter, ATP binding/permease protein [Oceanicola bats...ensis HTCC2597] gb|EAQ04798.1| ABC transporter, ATP binding/permease protein [Oceanicola batsensis HTCC2597] ZP_00997731.1 0.040 24% ...

  13. NCBI nr-aa BLAST: CBRC-DDIS-04-0000 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DDIS-04-0000 ref|NP_889639.1| ABC transporter, ATP-binding protein [Bordetella bronchiseptic...a RB50] emb|CAE33595.1| ABC transporter, ATP-binding protein [Bordetella bronchiseptica RB50] NP_889639.1 4e-68 38% ...

  14. Ground Testing of the EMCS Seed Cassette for Biocompatibility with the Cellular Slime Mold, Dictyostelium Discoideum

    Science.gov (United States)

    Hanely, Julia C.; Reinsch, Sigrid; Myers, Zachary A.; Freeman, John; Steele, Marianne K.; Sun, Gwo-Shing; Heathcote, David G.

    2014-01-01

    The European Modular Cultivation System, EMCS, was developed by ESA for plant experiments. To expand the use of flight verified hardware for various model organisms, we performed ground experiments to determine whether ARC EMCS Seed Cassettes could be adapted for use with cellular slime mold for future space flight experiments. Dictyostelium is a cellular slime mold that can exist both as a single-celled independent organism and as a part of a multicellular colony which functions as a unit (pseudoplasmodium). Under certain stress conditions, individual amoebae will aggregate to form multicellular structures. Developmental pathways are very similar to those found in Eukaryotic organisms, making this a uniquely interesting organism for use in genetic studies. Dictyostelium has been used as a genetic model organism for prior space flight experiments. Due to the formation of spores that are resistant to unfavorable conditions such as desiccation, Dictyostelium is also a good candidate for use in the EMCS Seed Cassettes. The growth substratum in the cassettes is a gridded polyether sulfone (PES) membrane. A blotter beneath the PES membranes contains dried growth medium. The goals of this study were to (1) verify that Dictyostelium are capable of normal growth and development on PES membranes, (2) develop a method for dehydration of Dictyostelium spores with successful recovery and development after rehydration, and (3) successful mock rehydration experiments in cassettes. Our results show normal developmental progression in two strains of Dictyostelium discoideum on PES membranes with a bacterial food source. We have successfully performed a mock rehydration of spores with developmental progression from aggregation to slug formation, and production of morphologically normal spores within 9 days of rehydration. Our results indicate that experiments on the ISS using the slime mold, Dictyostelium discoideum could potentially be performed in the flight verified hardware of

  15. Object Detection Based on Template Matching through Use of Best-So-Far ABC

    Directory of Open Access Journals (Sweden)

    Anan Banharnsakun

    2014-01-01

    Full Text Available Best-so-far ABC is a modified version of the artificial bee colony (ABC algorithm used for optimization tasks. This algorithm is one of the swarm intelligence (SI algorithms proposed in recent literature, in which the results demonstrated that the best-so-far ABC can produce higher quality solutions with faster convergence than either the ordinary ABC or the current state-of-the-art ABC-based algorithm. In this work, we aim to apply the best-so-far ABC-based approach for object detection based on template matching by using the difference between the RGB level histograms corresponding to the target object and the template object as the objective function. Results confirm that the proposed method was successful in both detecting objects and optimizing the time used to reach the solution.

  16. Nanoparticle-delivered VEGF-silencing cassette and suicide gene expression cassettes inhibit colon carcinoma growth in vitro and in vivo.

    Science.gov (United States)

    Leng, Aimin; Yang, Jing; Liu, Ting; Cui, Jianfang; Li, Xiu-Hua; Zhu, Yanan; Xiong, Ting; Chen, Yuxiang

    2011-12-01

    The strategies for tumor-specific expression of suicide genes and target tumor angiogenesis have been tested in tumors. However, the anti-tumor efficacy of the combination of these two strategies, particularly, delivering suicide gene and anti-angiogenesis agent by nanoparticles, has not yet been evaluated in colon carcinoma. We constructed a cassette to silence VEGF-A expression and express a fused yCDglyTK gene driven by tumor-specific promoter (shVEGF-CDTK). The DNA carrying shVEGF-CDTK was delivered into colon carcinoma cells by calcium phosphate nanoparticles (CPNPs). Cell proliferation was measured by MTT assay, and apoptosis was detected by flow cytometry. The anti-tumor effect of the combined cassette was tested in xenograft animal model. With 5-fluorocytosine (5-FC), CPNP-delivered shVEGF-CDTK DNA (CPNP-shVEGF-CDTK) showed high expression of fused yCDglyTK gene and effectively silenced VEGF-A expression in vitro and in vivo, which significantly inhibited colon carcinoma cell proliferation and induced apoptosis in vitro. With 5-FC, the systemic delivery of CPNP-shVEGF-CDTK significantly inhibited tumor growth in the colon carcinoma xenograft animal model. The combined cassette is obviously effective in inhibiting tumor cell proliferation and inducing apoptosis in vitro and tumor growth in vivo than the CPNP-shVEGF or CPNP-CDTK alone. The combination of VEGF-A-silencing and tumor-specific expression of suicide gene is an effective strategy for colon carcinoma treatment.

  17. The ABC protein turned chloride channel whose failure causes cystic fibrosis

    OpenAIRE

    Gadsby, David C.; Vergani, Paola; Csanády, László

    2006-01-01

    CFTR chloride channels are encoded by the gene mutated in patients with cystic fibrosis. These channels belong to the superfamily of ABC transporter ATPases. ATP-driven conformational changes, which in other ABC proteins fuel uphill substrate transport across cellular membranes, in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. New structural and biochemical information from prokaryotic ABC proteins and functional information from CFTR ch...

  18. Creating an iPhone application for collecting continuous ABC data.

    Science.gov (United States)

    Whiting, Seth W; Dixon, Mark R

    2012-01-01

    This paper provides an overview and task analysis for creating a continuous ABC data-collection application using Xcode on a Mac computer. Behavior analysts can program an ABC data collection system, complete with a customized list of target clients, antecedents, behaviors, and consequences to be recorded, and have the data automatically sent to an e-mail account after observations have concluded. Further suggestions are provided to customize the ABC data- collection system for individual preferences and clinical needs.

  19. Cystic Fibrosis Transmembrane Conductance Regulator (CFTR): CLOSED AND OPEN STATE CHANNEL MODELS.

    Science.gov (United States)

    Corradi, Valentina; Vergani, Paola; Tieleman, D Peter

    2015-09-18

    The cystic fibrosis transmembrane conductance regulator (CFTR) is a member of the ATP-binding cassette (ABC) transporter superfamily. CFTR controls the flow of anions through the apical membrane of epithelia. Dysfunctional CFTR causes the common lethal genetic disease cystic fibrosis. Transitions between open and closed states of CFTR are regulated by ATP binding and hydrolysis on the cytosolic nucleotide binding domains, which are coupled with the transmembrane (TM) domains forming the pathway for anion permeation. Lack of structural data hampers a global understanding of CFTR and thus the development of "rational" approaches directly targeting defective CFTR. In this work, we explored possible conformational states of the CFTR gating cycle by means of homology modeling. As templates, we used structures of homologous ABC transporters, namely TM(287-288), ABC-B10, McjD, and Sav1866. In the light of published experimental results, structural analysis of the transmembrane cavity suggests that the TM(287-288)-based CFTR model could correspond to a commonly occupied closed state, whereas the McjD-based model could represent an open state. The models capture the important role played by Phe-337 as a filter/gating residue and provide structural information on the conformational transition from closed to open channel.

  20. 基于 ABC-LS的传感器节点定位算法%SENSOR NODE LOCALISATION ALGORITHM BASED ON ABC-LS

    Institute of Scientific and Technical Information of China (English)

    程丽玲

    2015-01-01

    为了减少无线传感器网络节点的定位误差,提出一种人工蜂群算法(ABC)修正最小二乘(LS)定位误差的传感器节点定位算法( ABC-LS). 首先估计未知传感器节点与信标节点间距离,然后采用LS算法初步确定未知传感器节点位置,最后采用ABC算法对LS算法的节点定位误差进行修正,并采用仿真实验测试ABC-LS与其他节点定位算法的优劣. 结果表明,ABC-LS提高了无线传感器节点的定位精度.%In order to reduce the localisation error of wireless sensor network node, we propose a sensor node localisation algorithm ( ABC-LS), in which the artificial bee colony (ABC) algorithm is used to correct least squares (LS) algorithm.First, the distance between unknown sensor node and anchor node is estimated;then the location of unknown sensor node is initially determined by LS algorithm;finally, ABC algorithm is used to correct the node localisation error of LS algorithm.The pros and cons of ABC-LS algorithm and other node localisation algorithms are tested by simulation experiment, the experimental results show that ABC-LS improves the localisation accuracy of wireless sensor node.

  1. Synthesis of 5-oxyquinoline derivatives for reversal of multidrug resistance

    Directory of Open Access Journals (Sweden)

    Torsten Dittrich

    2012-10-01

    Full Text Available The inhibition of ABC (ATP binding cassette transporters is considered a powerful tool to reverse multidrug resistance. Zosuquidar featuring a difluorocyclopropyl-annulated dibenzosuberyl moiety has been found to be an inhibitor of the P-glycoprotein, one of the best-studied multidrug efflux pumps. Twelve 5-oxyisoquinoline derivatives, which are analogues of zosuquidar wherein the dibenzosuberyl-piperazine moiety is replaced by either a diarylaminopiperidine or a piperidone-derived acetal or thioacetal group, have been synthesized as pure enantiomers. Their inhibitory power has been evaluated for the bacterial multidrug-resistance ABC transporter LmrCD and fungal Pdr5. Four of the newly synthesized compounds reduced the transport activity to a higher degree than zosuquidar, being up to fourfold more efficient than the lead compound in the case of LmrCD and about two times better for Pdr5.

  2. Computer Simulations of Lipid Bilayers and Proteins

    DEFF Research Database (Denmark)

    Sonne, Jacob

    2006-01-01

    , the improved force field makes it possible to simulate the biologically relevant fluid ($L_{\\alpha}$) phase in an NPT ensemble, which is an important prerequisite for taking full advantage of the predictive power of MD simulations since the area per lipid need not be known prior to simulation. Chapter 4...... in the pressure profile since the pressure profile cannot be measured in traditional experiments. Even so, pressure profile calculations from MD simulations are not trivial due to both fundamental and technical issues. We addressed two such issues namely the uniqueness of the pressure profile and the effect......CD belongs to the adonesine triphosphate (ATP) binding cassette (ABC) transporter family that use ATP to drive active transport of a wide variety of compounds across cell membranes. BtuCD accounts for vitamin B12 import into Escherichia coli and is one of the only ABC transporters for which a reliable...

  3. Molecular Structure of the Human CFTR Ion Channel.

    Science.gov (United States)

    Liu, Fangyu; Zhang, Zhe; Csanády, László; Gadsby, David C; Chen, Jue

    2017-03-23

    The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that uniquely functions as an ion channel. Here, we present a 3.9 Å structure of dephosphorylated human CFTR without nucleotides, determined by electron cryomicroscopy (cryo-EM). Close resemblance of this human CFTR structure to zebrafish CFTR under identical conditions reinforces its relevance for understanding CFTR function. The human CFTR structure reveals a previously unresolved helix belonging to the R domain docked inside the intracellular vestibule, precluding channel opening. By analyzing the sigmoid time course of CFTR current activation, we propose that PKA phosphorylation of the R domain is enabled by its infrequent spontaneous disengagement, which also explains residual ATPase and gating activity of dephosphorylated CFTR. From comparison with MRP1, a feature distinguishing CFTR from all other ABC transporters is the helix-loop transition in transmembrane helix 8, which likely forms the structural basis for CFTR's channel function.

  4. Design of the storage location based on the ABC analyses

    Science.gov (United States)

    Jemelka, Milan; Chramcov, Bronislav; Kříž, Pavel

    2016-06-01

    The paper focuses on process efficiency and saving storage costs. Maintaining inventory through putaway strategy takes personnel time and costs money. The aim is to control inventory in the best way. The ABC classification based on Villefredo Pareto theory is used for a design of warehouse layout. New design of storage location reduces the distance of fork-lifters, total costs and it increases inventory process efficiency. The suggested solutions and evaluation of achieved results are described in detail. Proposed solutions were realized in real warehouse operation.

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    implicated in lipid movement and expressed in tissues with a role in sterol synthesis and absorption, might also be involved in sitosterol transport. Transport by the multidrug resistance P-glycoprotein (P-gp; Abcb1), the multidrug resistance-associated protein (Mrp1; Abcc1), the breast cancer resistance...... 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...

  6. Improved avidin-biotin-peroxidase complex (ABC) staining.

    Science.gov (United States)

    Cattoretti, G; Berti, E; Schiró, R; D'Amato, L; Valeggio, C; Rilke, F

    1988-02-01

    A considerable intensification of the avidin-biotin-peroxidase complex staining system (ABC) was obtained by sequentially overlaying the sections to be immunostained with an avidin-rich and a biotin-rich complex. Each sequential addition contributed to the deposition of horseradish peroxidase on the immunostained site and allowed the subsequent binding of a complementary complex. With this technique a higher dilution of the antisera could be used and minute amounts of antigen masked by the fixative could be demonstrated on paraffin sections.

  7. Light without substrate amendment: the bacterial luciferase gene cassette as a mammalian bioreporter

    Science.gov (United States)

    Close, Dan M.; Xu, Tingting; Smartt, Abby E.; Jegier, Pat; Ripp, Steven A.; Sayler, Gary S.

    2011-06-01

    Bioluminescent production represents a facile method for bioreporter detection in mammalian tissues. The lack of endogenous bioluminescent reactions in these tissues allows for high signal to noise ratios even at low signal strength compared to fluorescent signal detection. While the luciferase enzymes commonly employed for bioluminescent detection are those from class Insecta (firefly and click beetle luciferases), these are handicapped in that they require concurrent administration of a luciferin compound to elicit a bioluminescent signal. The bacterial luciferase (lux) gene cassette offers the advantages common to other bioluminescent proteins, but is simultaneously capable of synthesizing its own luciferin substrates using endogenously available cellular compounds. The longstanding shortcoming of the lux cassette has been its recalcitrance to function in the mammalian cellular environment. This paper will present an overview of the work completed to date to overcome this limitation and provide examples of mammalian lux-based bioreporter technologies that could provide the framework for advanced, biomedically relevant real-time sensor development.

  8. Methicillin-resistant Staphylococcus saprophyticus in Sweden carries various types of staphylococcal cassette chromosome mec (SCCmec).

    Science.gov (United States)

    Söderquist, B; Berglund, C

    2009-12-01

    Staphylococcus saprophyticus is a common cause of uncomplicated urinary tract infections and is usually susceptible to the antimicrobial agents used for their treatment. However, S. saprophyticus resistant to beta-lactam antibiotics and carrying mecA has been reported. Eight Swedish isolates of mecA-positive S. saprophyticus with diverse origin carrying at least three different types of staphylococcal cassette chromosome mec (SCCmec) are described here.

  9. Integration of multiple expression cassettes into mammalian genomes in a single step

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Andrijana Kriz, Katharina Schmid, Kurt Ballmer & Philipp Berger ### Abstract The modification of mammalian cells by the expression of multiple genes is a crucial technology in modern biological research. MultiLabel allows the modular assembly of independent expression units in a single plasmid which can be used for transient and stable modification of cells. In contrast to other methods, the assembly of the expression cassettes does not require restriction enzymes since i...

  10. Comparativa entre ABC y TDABC, aplicaci??n pr??ctica real = Comparison between ABC and TDABC, actual practical application

    OpenAIRE

    R??o Blanco, Nuria del

    2015-01-01

    Con este trabajo se pretende realizar un estudio comparativo de los sistemas de costeo ABC (Activity Based Costing, Costeo Basado en las Actividades) y TDABC (Time- Driven Activity Based Costing, Costeo basado en el tiempo invertido por actividad). En el trabajo se determinan las bases te??ricas de ambos m??todos, realizando una aplicaci??n pr??ctica real, lo que permite una comparativa entre ellos. Las bases te??ricas se fundamentan en la teor??a de los propulsores de estos m??todos. Por su ...

  11. Conservation of gene cassettes among diverse viruses of the human gut.

    Directory of Open Access Journals (Sweden)

    Samuel Minot

    Full Text Available Viruses are a crucial component of the human microbiome, but large population sizes, high sequence diversity, and high frequencies of novel genes have hindered genomic analysis by high-throughput sequencing. Here we investigate approaches to metagenomic assembly to probe genome structure in a sample of 5.6 Gb of gut viral DNA sequence from six individuals. Tests showed that a new pipeline based on DeBruijn graph assembly yielded longer contigs that were able to recruit more reads than the equivalent non-optimized, single-pass approach. To characterize gene content, the database of viral RefSeq proteins was compared to the assembled viral contigs, generating a bipartite graph with functional cassettes linking together viral contigs, which revealed a high degree of connectivity between diverse genomes involving multiple genes of the same functional class. In a second step, open reading frames were grouped by their co-occurrence on contigs in a database-independent manner, revealing conserved cassettes of co-oriented ORFs. These methods reveal that free-living bacteriophages, while usually dissimilar at the nucleotide level, often have significant similarity at the level of encoded amino acid motifs, gene order, and gene orientation. These findings thus connect contemporary metagenomic analysis with classical studies of bacteriophage genomic cassettes. Software is available at https://sourceforge.net/projects/optitdba/.

  12. Modulation of Gene Expression by Polymer Nanocapsule Delivery of DNA Cassettes Encoding Small RNAs.

    Directory of Open Access Journals (Sweden)

    Ming Yan

    Full Text Available Small RNAs, including siRNAs, gRNAs and miRNAs, modulate gene expression and serve as potential therapies for human diseases. Delivery to target cells remains the fundamental limitation for use of these RNAs in humans. To address this challenge, we have developed a nanocapsule delivery technology that encapsulates small DNA molecules encoding RNAs into a small (30 nm polymer nanocapsule. For proof of concept, we transduced DNA expression cassettes for three small RNAs. In one application, the DNA cassette encodes an shRNA transcriptional unit that downregulates CCR5 and protects from HIV-1 infection. The DNA cassette nanocapsules were further engineered for timed release of the DNA cargo for prolonged knockdown of CCR5. Secondly, the nanocapsules provide an efficient means for delivery of gRNAs in the CRISPR/Cas9 system to mutate integrated HIV-1. Finally, delivery of microRNA-125b to mobilized human CD34+ cells enhances survival and expansion of the CD34+ cells in culture.

  13. Linear friction weld process monitoring of fixture cassette deformations using empirical mode decomposition

    Science.gov (United States)

    Bakker, O. J.; Gibson, C.; Wilson, P.; Lohse, N.; Popov, A. A.

    2015-10-01

    Due to its inherent advantages, linear friction welding is a solid-state joining process of increasing importance to the aerospace, automotive, medical and power generation equipment industries. Tangential oscillations and forge stroke during the burn-off phase of the joining process introduce essential dynamic forces, which can also be detrimental to the welding process. Since burn-off is a critical phase in the manufacturing stage, process monitoring is fundamental for quality and stability control purposes. This study aims to improve workholding stability through the analysis of fixture cassette deformations. Methods and procedures for process monitoring are developed and implemented in a fail-or-pass assessment system for fixture cassette deformations during the burn-off phase. Additionally, the de-noised signals are compared to results from previous production runs. The observed deformations as a consequence of the forces acting on the fixture cassette are measured directly during the welding process. Data on the linear friction-welding machine are acquired and de-noised using empirical mode decomposition, before the burn-off phase is extracted. This approach enables a direct, objective comparison of the signal features with trends from previous successful welds. The capacity of the whole process monitoring system is validated and demonstrated through the analysis of a large number of signals obtained from welding experiments.

  14. Genomic donor cassette sharing during VLRA and VLRC assembly in jawless vertebrates.

    Science.gov (United States)

    Das, Sabyasachi; Li, Jianxu; Holland, Stephen J; Iyer, Lakshminarayan M; Hirano, Masayuki; Schorpp, Michael; Aravind, L; Cooper, Max D; Boehm, Thomas

    2014-10-14

    Lampreys possess two T-like lymphocyte lineages that express either variable lymphocyte receptor (VLR) A or VLRC antigen receptors. VLRA(+) and VLRC(+) lymphocytes share many similarities with the two principal T-cell lineages of jawed vertebrates expressing the αβ and γδ T-cell receptors (TCRs). During the assembly of VLR genes, several types of genomic cassettes are inserted, in step-wise fashion, into incomplete germ-line genes to generate the mature forms of antigen receptor genes. Unexpectedly, the structurally variable components of VLRA and VLRC receptors often possess partially identical sequences; this phenomenon of module sharing between these two VLR isotypes occurs in both lampreys and hagfishes. By contrast, VLRA and VLRC molecules typically do not share their building blocks with the structurally analogous VLRB receptors that are expressed by B-like lymphocytes. Our studies reveal that VLRA and VLRC germ-line genes are situated in close proximity to each other in the lamprey genome and indicate the interspersed arrangement of isotype-specific and shared genomic donor cassettes; these features may facilitate the shared cassette use. The genomic structure of the VLRA/VLRC locus in lampreys is reminiscent of the interspersed nature of the TCRA/TCRD locus in jawed vertebrates that also allows the sharing of some variable gene segments during the recombinatorial assembly of TCR genes.

  15. Circulating cathodic antigen cassette test versus haematuria strip test in diagnosis of urinary schistosomiasis.

    Science.gov (United States)

    El-Ghareeb, Azza S; Abd El Motaleb, Ghada S; Waked, Nevien Maher; Osman Hany Kamel, Nancy; Aly, Nagwa Shaban

    2016-12-01

    Urinary schistosomiasis caused by Schistosoma haematobium constitutes a major public health problem in many tropical and sub-tropical countries. This study was conducted to evaluate circulating cathodic antigen cassette test and haematuria strip test for detection of S. haematobium in urine samples and to evaluate their screening performance among the study population. Microscopy was used as a gold standard. A total of 600 urine samples were examined by microscopy for detection of S. haematobium eggs, screened for microhaematuria using Self-Stik reagent strips and screened for circulating cathodic antigen (CCA) using the urine-CCA cassette test. The specificity of CCA, microhaematuria and macrohaematuria was 96.4, 40.6 and 31.2 % respectively while the sensitivity was 88.2, 99.3 and 100 % respectively which was statistically significant (P < 0.001). These findings suggest that using of urine-CCA cassette test in diagnosis of urinary schistosomiasis is highly specific (96.4 %) compared with the highly sensitive haematuria strip test (100 %). The degree of agreement between microscopic examination and CCA detection was 99.3 % with highly statistically significant difference (P < 0.001). The combination of two techniques could potentially use for screening and mapping of S. haematobium infection.

  16. Extending the Glucosyl Ceramide Cassette Approach: Application in the Total Synthesis of Ganglioside GalNAc-GM1b

    Directory of Open Access Journals (Sweden)

    Miku Konishi

    2013-12-01

    Full Text Available The development of a novel cyclic glucosyl ceramide cassette acceptor for efficient glycolipid syntheses was investigated. p-Methoxybenzyl (PMB groups were selected as protecting groups at C2 and C3 of the glucose residue with the aim of improving the functionality of the cassette acceptor. The choice of the PMB group resulted in a loss of β-selectivity, which was corrected by using an appropriate tether to control the spatial arrangement and the nitrile solvent effect. To investigate the effect of linker structure on the β-selectivity of intramolecular glycosylation, several linkers for tethering the glucose and ceramide moiety were designed and prepared, namely, succinyl, glutaryl, dimethylmalonyl, and phthaloyl esters. The succinyl ester linker was the best for accessing the cassette form. The newly designed glucosyl ceramide cassette acceptor was then applied in the total synthesis of ganglioside GalNAc-GM1b.

  17. Structure of a Type-1 Secretion System ABC Transporter.

    Science.gov (United States)

    Morgan, Jacob L W; Acheson, Justin F; Zimmer, Jochen

    2017-03-07

    Type-1 secretion systems (T1SSs) represent a widespread mode of protein secretion across the cell envelope in Gram-negative bacteria. The T1SS is composed of an inner-membrane ABC transporter, a periplasmic membrane-fusion protein, and an outer-membrane porin. These three components assemble into a complex spanning both membranes and providing a conduit for the translocation of unfolded polypeptides. We show that ATP hydrolysis and assembly of the entire T1SS complex is necessary for protein secretion. Furthermore, we present a 3.15-Å crystal structure of AaPrtD, the ABC transporter found in the Aquifex aeolicus T1SS. The structure suggests a substrate entry window just above the transporter's nucleotide binding domains. In addition, highly kinked transmembrane helices, which frame a narrow channel not observed in canonical peptide transporters, are likely involved in substrate translocation. Overall, the AaPrtD structure supports a polypeptide transport mechanism distinct from alternating access.

  18. THE IMPACT OF ACQUISITION ON FINANCIAL PERFORMANCE OF PT. ABC

    Directory of Open Access Journals (Sweden)

    Novian Zen

    2016-09-01

    Full Text Available This study aimed to analyze the financial performance of the subsidiary company (PT ABC before and after acquired by the holding company (PT XYZ. The examined ratios of the financial performance were profitability and capital structure for the period of 2010-2014. This study utilized the t test tool. In the first and second year after the acquisition, the result shows that with the existence of business synergy, there was a change in financial performance although it was insignificant. Furthermore, in the third year, there was absolutely no change; however, in the fourth year, there was an insignifant change. The implications of this research indicates the motive or objective of the shareholders (K-State-owned Enterprises in assigning the holding company (XYZ to restructure the financial performance and improve capital structure of its subsidiary company (PT ABC by conducting a business synergy has not been reached.Keywords: acquisition, financial performance, improved capital structure, business synergy and financial reports

  19. Bicontinuous Porous Carbon Films Templated with ABC Triblock Copolymers

    Science.gov (United States)

    Cavicchi, Kevin; Deng, Guodong; Vogt, Bryan

    2014-03-01

    Mesoporous carbons are useful for a range of applications such as separation and catalysis. A route to prepare porous materials is through cooperative self-assembly of a carbon precursor (e.g. phenolic resin) and a block copolymer, in which the precursor is selectively soluble, to drive mesophase formation. Typical soft templating uses AB or ABA block copolymers, which form classical morphologies, such as spheres, cylinders, and lamellae. Switching to an ABC type block copolymer provides greater flexibility in the design of the morphology potentially opening up larger processing windows for complex structures, such as bicontinuous morphologies. This presentation will discuss efforts to prepare bicontinuous porous carbon thin films using an ABC triblock copolymer of poly(ethylene oxide)-block-poly(ethyl acrylate)-block-polystyrene via spin-coating and a series of thermal annealing steps. It will be shown that direct thermal annealing can produce high porosity (~60%) carbon fiber networks. In addition, adding a solvent annealing step prior to the thermal annealing steps is able to produce longer range order structures with a small window of an ordered bicontinuous morphology. These high porosity films with organized fibers are promising for energy and separation applications.

  20. 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

  1. The ABCs of Activity-Based Costing: A Cost Containment and Reallocation Tool.

    Science.gov (United States)

    Turk, Frederick J.

    1992-01-01

    This article describes activity-based costing (ABC) and how this tool may help management understand the costs of major activities and identify possible alternatives. Also discussed are the traditional costing systems used by higher education and ways of applying ABC to higher education. (GLR)

  2. The Role of Activity Based Costing (ABC) in Educational Support Services: A White Paper.

    Science.gov (United States)

    Edds, Daniel B.

    Many front-line managers who are assuming more financial responsibility for their organizations find traditional cost accounting inadequate for their needs and are turning to Activity Based Costing (ABC). ABC is not a financial reporting system to serve the needs of regulatory agencies, but a tool that tracks costs from the general ledger…

  3. Creating an iPhone Application for Collecting Continuous ABC Data

    Science.gov (United States)

    Whiting, Seth W.; Dixon, Mark R.

    2012-01-01

    This paper provides an overview and task analysis for creating a continuous ABC data- collection application using Xcode on a Mac computer. Behavior analysts can program an ABC data collection system, complete with a customized list of target clients, antecedents, behaviors, and consequences to be recorded, and have the data automatically sent to…

  4. Applying the Post-Modern Double ABC-X Model to Family Food Insecurity

    Science.gov (United States)

    Hutson, Samantha; Anderson, Melinda; Swafford, Melinda

    2015-01-01

    This paper develops the argument that using the Double ABC-X model in family and consumer sciences (FCS) curricula is a way to educate nutrition and dietetics students regarding a family's perceptions of food insecurity. The Double ABC-X model incorporates ecological theory as a basis to explain family stress and the resulting adjustment and…

  5. A Quantitative Analysis of the Behavioral Checklist of the Movement ABC Motor Test

    Science.gov (United States)

    Ruiz, Luis Miguel; Gomez, Marta; Graupera, Jose Luis; Gutierrez, Melchor; Linaza, Jose Luis

    2007-01-01

    The fifth section of the Henderson and Sugden's Movement ABC Checklist is part of the general Checklist that accompanies The Movement ABC Battery. The authors maintain that the analysis of this section must be mainly qualitative instead of quantitative. The main objective of this study was to employ a quantitative analysis of this behavioural…

  6. Conformational dynamics in substrate-binding domains influences transport in the ABC importer GlnPQ

    NARCIS (Netherlands)

    Gouridis, Giorgos; Schuurman-Wolters, Geesina; Ploetz, Evelyn; Husada, Florence; Vietrov, Ruslan; de Boer, Marijn; Cordes, Thorben; Poolman, Bert

    2015-01-01

    The conformational dynamics in ABC transporters is largely elusive. The ABC importer GlnPQ from Lactococcus lactis has different covalently linked substrate-binding domains (SBDs), thus making it an excellent model system to elucidate the dynamics and role of the SBDs in transport. We demonstrate by

  7. Parents' Perspectives on Braille Literacy: Results from the ABC Braille Study

    Science.gov (United States)

    Kamei-Hannan, Cheryl; Sacks, Sharon Zell

    2012-01-01

    Introduction: Parents who were the primary caretakers of children in the Alphabetic and Contracted Braille Study (ABC Braille Study) revealed their perspectives about braille literacy. Methods: A 30-item questionnaire was constructed by the ABC Braille research team, and researchers conducted telephone interviews with 31 parents who were the…

  8. The ABCs of highly effective presentations: a customer-centered approach.

    Science.gov (United States)

    Clark, V B

    1999-01-01

    In the world of adult education where the learners have complex expectations, the educator must make an extra effort to meet the customers' (learners') needs. This article describes how an educator can make every presentation customer-centered by knowing the ABCs of highly effective presentations. The ABCs, when applied, can jump-start presentations and help the presenter meet or exceed learners' expectations.

  9. Enhanced performance of methamphetamine lateral flow cassettes using an electronic lateral flow reader.

    Science.gov (United States)

    Smith, Jerome P; Sammons, Deborah L; Robertson, Shirley A; Snawder, John E

    2015-01-01

    Surface contamination from methamphetamine in meth labs continues to be a problem. We had previously developed a lateral flow assay cassette for field detection of methamphetamine contamination that is commercially available and has been used by a number of groups to assess contamination. This cassette uses the complete disappearance of the test line as an end point for detection of 50 ng/100 cm2 of methamphetamine contamination for surface sampling with cotton swabs. In the present study, we further evaluate the response of the cassettes using an electronic lateral flow reader to measure the intensities of the test and control lines. The cassettes were capable of detecting 0.25 ng/ml for calibration solutions. For 100 cm2 ceramic tiles that were spiked with methamphetamine and wiped with cotton-tipped wooden swabs wetted in assay/sampling buffer, 1 ng/tile was detected using the reader. Semi-quantitative results can be produced over the range 0-10 ng/ml for calibration solutions and 0-25 ng/tile for spiked tiles using either a 4-parameter logistic fit of test line intensity versus concentration or spiked mass or the ratio of the control line to the test line intensity fit to concentration or spiked mass. Recovery from the tiles was determined to be about 30% using the fitted curves. Comparison of the control line to the test line was also examined as a possible visual detection end point and it was found that the control line became more intense than the test line at 0.5 to 1 ng/ml for calibration solutions or 1 to 2 ng/tile for spiked tiles. Thus the lateral flow cassettes for methamphetamine have the potential to produce more sensitive semi-quantitative results if an electronic lateral flow reader is used and can be more sensitive for detection if the comparison of the control line to the test line is used as the visual end point.

  10. Accuracy of the ABC/2 score for intracerebral hemorrhage: Systematic review and analysis of MISTIE, CLEAR-IVH, CLEAR III

    Science.gov (United States)

    Webb, Alastair JS; 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

    2015-01-01

    Background and Purpose 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 CT-based planimetry (CTP). Methods In MISTIE-II, 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 5ml and relative difference within 20%. Determinants of ABC/2 accuracy were assessed by logistic regression. Results In 4369 scans from 507 patients, CTP was more strongly correlated with RC-ABC (r2=0.93) than site-ABC (r2=0.87). Although RC-ABC overestimated CTP-based volume on average (RC-ABC=15.2cm3, CTP=12.7cm3), agreement was reasonable when categorised into mild, moderate and severe ICH (kappa 0.75, p<0.001). This was consistent with overestimation of ICH volume in 6/8 previous studies. Agreement with CTP was greater for RC-ABC (84% within 5ml; 48% of scans within 20%) than for site-ABC (81% within 5ml; 41% within 20%). RC-ABC had moderate accuracy for detecting ≥ 5ml change in CTP volume between consecutive scans (sensitivity 0.76, specificity 0.86) and was more accurate with smaller ICH, thalamic haemorrhage and homogeneous clots. Conclusions ABC/2 scores at local or central sites are sufficiently accurate to categorise 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. Clinical Trial Registration MISTIE-II NCT00224770; CLEAR-III NCT00784134; www.clinicaltrials.gov PMID:26243227

  11. Application of activity-based costing (ABC) for a Peruvian NGO healthcare provider.

    Science.gov (United States)

    Waters, H; Abdallah, H; Santillán, D

    2001-01-01

    This article describes the application of activity-based costing (ABC) to calculate the unit costs of the services for a health care provider in Peru. While traditional costing allocates overhead and indirect costs in proportion to production volume or to direct costs, ABC assigns costs through activities within an organization. ABC uses personnel interviews to determine principal activities and the distribution of individual's time among these activities. Indirect costs are linked to services through time allocation and other tracing methods, and the result is a more accurate estimate of unit costs. The study concludes that applying ABC in a developing country setting is feasible, yielding results that are directly applicable to pricing and management. ABC determines costs for individual clinics, departments and services according to the activities that originate these costs, showing where an organization spends its money. With this information, it is possible to identify services that are generating extra revenue and those operating at a loss, and to calculate cross subsidies across services. ABC also highlights areas in the health care process where efficiency improvements are possible. Conclusions about the ultimate impact of the methodology are not drawn here, since the study was not repeated and changes in utilization patterns and the addition of new clinics affected applicability of the results. A potential constraint to implementing ABC is the availability and organization of cost information. Applying ABC efficiently requires information to be readily available, by cost category and department, since the greatest benefits of ABC come from frequent, systematic application of the methodology in order to monitor efficiency and provide feedback for management. The article concludes with a discussion of the potential applications of ABC in the health sector in developing countries.

  12. Systematic Identification of Rice ABC1 Gene Family and Its Response to Abiotic Stress

    Institute of Scientific and Technical Information of China (English)

    GAO Qing-song; ZHANG Dan; Xu Liang; XU Chen-wu

    2011-01-01

    Members of the activity of bc1 complex (ABC1) family are protein kinases that are widely found in prokaryotes and eukaryotes.Previous studies showed that several plant ABC1 genes participated in the abiotic stress response.Here,we present the systematic identification of rice and Arabidopsis ABC1 genes and the expression analysis of rice ABC1 genes.A total of 15 and 17 ABC1 genes from the rice and Arabidopsis genomes,respectively,were identified using a bioinformatics approach.Phylogenetic analyses of these proteins suggested that the divergence of this family had occurred and their main characteristics were established before the monocot-dicot split.Indeed,species-specific expansion contributed to the evolution of this family in rice and Arabidopsis after the monocot-dicot split.Intron/exon structure analysis indicated that most of the orthologous genes had similar exon sizes,but diverse intron sizes,and the rice genes contained larger introns,moreover,intron gain was an important event accompanying the recent evolution of the rice ABC1 family.Multiple sequence alignment revealed one conserved amino acid segment and four conserved amino acids in the ABC1 domain.Online subcellular localization predicted that nine rice ABC1 proteins were localized in chloroplasts.Real-time RT-PCR established that the rice ABC1 genes were primarily expressed in leaves and the expression could be modulated by a broad range of abiotic factors such as H2O2,abscisic acid,low temperature,drought,darkness and high salinity.These results reveal that the rice ABC1 gene family plays roles in the environmental stress response and specific biological processes of rice.

  13. Low levels of graphene and graphene oxide inhibit cellular xenobiotic defense system mediated by efflux transporters.

    Science.gov (United States)

    Liu, Su; Jiang, Wei; Wu, Bing; Yu, Jing; Yu, Haiyan; Zhang, Xu-Xiang; Torres-Duarte, Cristina; Cherr, Gary N

    2016-01-01

    Low levels of graphene and graphene oxide (GO) are considered to be environmentally safe. In this study, we analyzed the potential effects of graphene and GO at relatively low concentrations on cellular xenobiotic defense system mediated by efflux transporters. The results showed that graphene (graphene and GO at the nontoxic concentrations could increase calcein-AM (CAM, an indicator of membrane ATP-binding cassette (ABC) transporter) activity) accumulation, indicating inhibition of ABC transporters' efflux capabilities. This inhibition was observed even at 0.005 μg/mL graphene and 0.05 μg/mL GO, which are 100 times and 400 times lower than their lowest toxic concentration from cytotoxicity experiments, respectively. The inhibition of ABC transporters significantly increased the toxicity of paraquat and arsenic, known substrates of ABC transporters. The inhibition of ABC transporters was found to be based on graphene and GO damaging the plasma membrane structure and fluidity, thus altering functions of transmembrane ABC transporters. This study demonstrates that low levels of graphene and GO are not environmentally safe since they can significantly make cell more susceptible to other xenobiotics, and this chemosensitizing activity should be considered in the risk assessment of graphene and GO.

  14. MgAtr7, a new type of ABC transporter from Mycosphaerella graminicola involved in iron homeostasis

    NARCIS (Netherlands)

    Zwiers, L.H.; Roohparvar, R.; Waard, de M.A.

    2007-01-01

    The ABC transporter-encoding gene MgAtr7 from the wheat pathogen Mycosphaerella graminicola was cloned based upon its high homology to ABC transporters involved in azole-fungicide sensitivity. Genomic and cDNA sequences indicated that the N-terminus of this ABC transporter contains a motif character

  15. The replication origin of a repABC plasmid

    Directory of Open Access Journals (Sweden)

    Cevallos Miguel A

    2011-06-01

    Full Text Available Abstract Background repABC operons are present on large, low copy-number plasmids and on some secondary chromosomes in at least 19 α-proteobacterial genera, and are responsible for the replication and segregation properties of these replicons. These operons consist, with some variations, of three genes: repA, repB, and repC. RepA and RepB are involved in plasmid partitioning and in the negative regulation of their own transcription, and RepC is the limiting factor for replication. An antisense RNA encoded between the repB-repC genes modulates repC expression. Results To identify the minimal region of the Rhizobium etli p42d plasmid that is capable of autonomous replication, we amplified different regions of the repABC operon using PCR and cloned the regions into a suicide vector. The resulting vectors were then introduced into R. etli strains that did or did not contain p42d. The minimal replicon consisted of a repC open reading frame under the control of a constitutive promoter with a Shine-Dalgarno sequence that we designed. A sequence analysis of repC revealed the presence of a large A+T-rich region but no iterons or DnaA boxes. Silent mutations that modified the A+T content of this region eliminated the replication capability of the plasmid. The minimal replicon could not be introduced into R. etli strain containing p42d, but similar constructs that carried repC from Sinorhizobium meliloti pSymA or the linear chromosome of Agrobacterium tumefaciens replicated in the presence or absence of p42d, indicating that RepC is an incompatibility factor. A hybrid gene construct expressing a RepC protein with the first 362 amino acid residues from p42d RepC and the last 39 amino acid residues of RepC from SymA was able to replicate in the presence of p42d. Conclusions RepC is the only element encoded in the repABC operon of the R. etli p42d plasmid that is necessary and sufficient for plasmid replication and is probably the initiator protein. The ori

  16. Monte Carlo simulations of ABC stacked kagome lattice films

    Science.gov (United States)

    Yerzhakov, H. V.; Plumer, M. L.; Whitehead, J. P.

    2016-05-01

    Properties of films of geometrically frustrated ABC stacked antiferromagnetic kagome layers are examined using Metropolis Monte Carlo simulations. The impact of having an easy-axis anisotropy on the surface layers and cubic anisotropy in the interior layers is explored. The spin structure at the surface is shown to be different from that of the bulk 3D fcc system, where surface axial anisotropy tends to align spins along the surface [1 1 1] normal axis. This alignment then propagates only weakly to the interior layers through exchange coupling. Results are shown for the specific heat, magnetization and sub-lattice order parameters for both surface and interior spins in three and six layer films as a function of increasing axial surface anisotropy. Relevance to the exchange bias phenomenon in IrMn3 films is discussed.

  17. Counting Smooth Solutions to the Equation A+B=C

    CERN Document Server

    Lagarias, J C

    2011-01-01

    This paper studies integer solutions to the Diophantine equation A+B=C in which none of A, B, C have a large prime factor. We set H(A, B,C) = max(|A|, |B|, |C|), and consider primitive solutions (gcd}(A, B, C)=1) having no prime factor p larger than (log H(A, B,C))^K, for a given finite K. On the assumption that the Generalized Riemann hypothesis (GRH) holds, we show that for any K > 8 there are infinitely many such primitive solutions having no prime factor larger than (log H(A, B, C))^K. We obtain in this range an asymptotic formula for the number of such suitably weighted primitive solutions.

  18. Monte Carlo simulations of ABC stacked kagome lattice films.

    Science.gov (United States)

    Yerzhakov, H V; Plumer, M L; Whitehead, J P

    2016-05-18

    Properties of films of geometrically frustrated ABC stacked antiferromagnetic kagome layers are examined using Metropolis Monte Carlo simulations. The impact of having an easy-axis anisotropy on the surface layers and cubic anisotropy in the interior layers is explored. The spin structure at the surface is shown to be different from that of the bulk 3D fcc system, where surface axial anisotropy tends to align spins along the surface [1 1 1] normal axis. This alignment then propagates only weakly to the interior layers through exchange coupling. Results are shown for the specific heat, magnetization and sub-lattice order parameters for both surface and interior spins in three and six layer films as a function of increasing axial surface anisotropy. Relevance to the exchange bias phenomenon in IrMn3 films is discussed.

  19. Observation of an ABC effect in proton-proton collisions

    CERN Document Server

    Dymov, S; Kacharava, A; Khoukaz, A; Komarov, V; Kulessa, P; Kulikov, A; Kurbatov, V; Macharashvili, G; Merzliakov, S; Mielke, M; Mikirtychiants, S; Nekipelov, M; Nioradze, M; Ohm, H; Rathmann, F; Ströher, H; Tsirkov, D; Uzikov, Yu; Valdau, Yu; Wilkin, C; Yaschenko, S; Zalikhanov, B

    2009-01-01

    The cross section for inclusive multipion production in the pp->ppX reaction was measured at COSY-ANKE at four beam energies, 0.8, 1.1, 1.4, and 2.0 GeV, for low excitation energy in the final pp system, such that the diproton quasi-particle is in the 1S0 state. At the three higher energies the missing mass Mx spectra show a strong enhancement at low Mx, corresponding to an ABC effect that moves steadily to larger values as the energy is increased. Despite the missing-mass structure looking very different at 0.8 GeV, the variation with Mx and beam energy are consistent with two-pion production being mediated through the excitation of two Delta(1232) isobars, coupled to S-- and D-- states of the initial pp system.

  20. Supersymmetric Theory of Stochastic ABC Model: A Numerical Study

    CERN Document Server

    Ovchinnikov, Igor V; Ensslin, Torsten A; Wang, Kang L

    2016-01-01

    In this paper, we investigate numerically the stochastic ABC model, a toy model in the theory of astrophysical kinematic dynamos, within the recently proposed supersymmetric theory of stochastics (STS). STS characterises stochastic differential equations (SDEs) by the spectrum of the stochastic evolution operator (SEO) on elements of the exterior algebra or differentials forms over the system's phase space, X. STS can thereby classify SDEs as chaotic or non-chaotic by identifying the phenomenon of stochastic chaos with the spontaneously broken topological supersymmetry that all SDEs possess. We demonstrate the following three properties of the SEO, deduced previously analytically and from physical arguments: the SEO spectra for zeroth and top degree forms never break topological supersymmetry, all SDEs possesses pseudo-time-reversal symmetry, and each de Rahm cohomology class provides one supersymmetric eigenstate. Our results also suggests that the SEO spectra for forms of complementary degrees, i.e., k and ...

  1. 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.

    Science.gov (United States)

    Helms, Hans Christian; Hersom, Maria; Kuhlmann, Louise Borella; Badolo, Lasina; Nielsen, Carsten Uhd; Brodin, Birger

    2014-09-01

    Efflux transporters of the ATP-binding cassette superfamily including breast cancer resistance protein (Bcrp/Abcg2), P-glycoprotein (P-gp/Abcb1) and multidrug resistance-associated proteins (Mrp's/Abcc's) are expressed in the blood-brain barrier (BBB). The aim of this study was to investigate 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). Bidirectional transport studies with (3)H-digoxin, (3)H-estrone-3-sulphate and (3)H-etoposide revealed polarized transport favouring the brain-to-blood direction for all substrates. Steady state efflux ratios of 2.5 ± 0.2 for digoxin, 4.4 ± 0.5 for estrone-3-sulphate and 2.4 ± 0.1 for etoposide were observed. These were reduced to 1.1 ± 0.08, 1.4 ± 0.2 and 1.5 ± 0.1, by addition of verapamil (digoxin), Ko143 (estrone-3-sulphate) or zosuquidar + reversan (etoposide), respectively. Brain-to-blood permeability of all substrates was investigated in the presence of the efflux transporter inhibitors verapamil, Ko143, zosuquidar, reversan and MK 571 alone or in combinations. Digoxin was mainly transported via P-gp, estrone-3-sulphate via Bcrp and Mrp's and etoposide via P-gp and Mrp's. The expression of P-gp, Bcrp and Mrp-1 was confirmed using immunocytochemistry. The findings indicate that P-gp, Bcrp and at least one isoform of Mrp are functionally expressed in our bovine/rat co-culture model and that the model is suitable for investigations of small molecule transport.

  2. Applying Activity Based Costing (ABC Method to Calculate Cost Price in Hospital and Remedy Services

    Directory of Open Access Journals (Sweden)

    A Dabiri

    2012-04-01

    Full Text Available Background: Activity Based Costing (ABC is one of the new methods began appearing as a costing methodology in the 1990. It calculates cost price by determining the usage of resources. In this study, ABC method was used for calculating cost price of remedial services in hospitals.Methods: To apply ABC method, Shahid Faghihi Hospital was selected. First, hospital units were divided into three main departments: administrative, diagnostic, and hospitalized. Second, activity centers were defined by the activity analysis method. Third, costs of administrative activity centers were allocated into diagnostic and operational departments based on the cost driver. Finally, with regard to the usage of cost objectives from services of activity centers, the cost price of medical services was calculated.Results: The cost price from ABC method significantly differs from tariff method. In addition, high amount of indirect costs in the hospital indicates that capacities of resources are not used properly.Conclusion: Cost price of remedial services with tariff method is not properly calculated when compared with ABC method. ABC calculates cost price by applying suitable mechanisms but tariff method is based on the fixed price. In addition, ABC represents useful information about the amount and combination of cost price services.

  3. 整合作业成本与经济附加值的ABC&EVA系统

    Institute of Scientific and Technical Information of China (English)

    白明

    2006-01-01

    整合作业成本(activity-based costing,缩写ABC)与经济附加值(economic value added,缩写EVA)的产物是ABC&EVA系统.ABC&EVA系统不仅能够揭示成本对象所创造的经济价值,而且还能够将ABC从单纯的成本计算扩展到业绩评价.本文在分析ABC&EVA系统原理的基础上,结合案例对ABC&EVA系统运行步骤加以说明.

  4. Staphylococcal Cassette Chromosome mec Types Among Methicillin-Resistant Staphylococcus aureus in Northern Iran

    Science.gov (United States)

    Taherirad, Akram; Jahanbakhsh, Roghayeh; Shakeri, Fatemeh; Anvary, Shaghayegh; Ghaemi, Ezzat Allah

    2016-01-01

    Background Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial and community-acquired infections around the world. Staphylococcal cassette chromosome mec (SCCmec) typing methods are often used to study MRSA molecular epidemiology. Objectives The current study was designed to explore the distribution profiles of different SCCmec types among methicillin-resistant S. aureus strains isolated from hospitals in Gorgan, in northern Iran, and to correlate the types into observed bacterial virulence factors. Materials and Methods Staphylococcal cassette chromosome mec typing of 62 MRSA strains isolated from patients and health-care workers in Gorgan was performed using multiplex polymerase chain reaction (PCR) assay. The prevalence of the strains was then compared according to isolation source, antibiotic susceptibility profiles, biofilm production, and the presence of the Panton-Valentine gene in isolates. Results The most common SCCmec type was type III, with a frequency rate of 76%, followed by types IV, I, and V, with frequency rates of 11.2%, 4.8%, and 3.2%, respectively; three isolates (4.8%) were not typeable by this method. SCCmec type I was only isolated from blood culture, and types IV and V were mainly isolated from wounds and urine samples; SCCmec type III was isolated from all of the clinically samples. All of the MRSA strains that were isolated from healthy carriers were type III. Multidrug resistance in the type III strains was higher compared to the other types. The frequencies of Panton-Valentine and biofilm production were significantly lower in the type III strains compared to the other SCCmec types (P < 0.05). Conclusions Similarly to other geographical regions of Iran, the SCCmec type III MRSA strain was the most frequently isolated strain from patients in Gorgan. Staphylococcal cassette chromosome mec type III showed fewer virulence factors compared to other SCCmec types. PMID:27800133

  5. Hygromycin B and apramycin antibiotic resistance cassettes for use in Campylobacter jejuni.

    Directory of Open Access Journals (Sweden)

    Andrew Cameron

    Full Text Available Campylobacter jejuni genetic manipulation is restricted by the limited number of antibiotic resistance cassettes available for use in this diarrheal pathogen. In this study, two antibiotic resistance cassettes were developed, encoding for hygromycin B and apramycin resistance, for use in mutagenesis or for selection of gene expression and complementation constructs in C. jejuni. First, the marker genes were successfully modified to allow for insertional mutagenesis or deletion of a gene-of-interest, and were bracketed with restriction sites for the facilitation of site-specific cloning. These hygromycin B and apramycin markers are encoded by plasmids pAC1H and pAC1A, respectively. We also modified an insertional gene-delivery vector to create pRRH and pRRA, containing the hygromycin B and apramycin resistance genes, and 3 unique restriction sites for the directional introduction of genes into the conserved multi-copy rRNA gene clusters of the C. jejuni chromosome. We determined the effective antibiotic concentrations required for selection, and established that no harmful effects or fitness costs were associated with carrying hygromycin B or apramycin resistance under standard C. jejuni laboratory conditions. Using these markers, the arylsulfatase reporter gene astA was deleted, and the ability to genetically complement the astA deletion using pRRH and pRRA for astA gene insertion was demonstrated. Furthermore, the relative levels of expression from the endogenous astA promoter were compared to that of polycistronic mRNA expression from the constitutive promoter upstream of the resistance gene. The development of additional antibiotic resistance cassettes for use in Campylobacter will enable multiple gene deletion and expression combinations as well as more in-depth study of multi-gene systems important for the survival and pathogenesis of this important bacterium.

  6. A new tocograph with cassette recording system and separate servo graphic recorder.

    Science.gov (United States)

    Zahn, V; Seitz, P

    1979-01-01

    In order to register contractional activity, especially in the case of high-risk pregnancies, a tocograph was develop by means of which the contractions are registered by a small cassette recorder, which the patient can carry by about with her. A separate graphic recorder is responsible for the playback and this recorder remains at the doctor's practice. The patient is able to register her contractions herself as the unit is so simple to use. The recording section weighs only 500 grams, including the specially developed pressure transducer with optical distance-meter. The tocograph is produced in series.

  7. The ABC Catering Services Ltd.ABC食品供应服务公司

    Institute of Scientific and Technical Information of China (English)

    黄权初

    2001-01-01

    @@ 1 Introduction ABC Catering Services Ltd. has long recognized its needs to compete effectively in its key markets in the Pacific Rim. With ABC' s historical focus on delivering almost faultless service, comparatively little attention has been given to the supply chain cost of that delivery. However, the new kitchen at Seoul, was open in 1997, added more workload to the company. Things have not been working well since then.The ABC Corporation realizes that it is necessary to reduce supply chain costs and to improve its operation efficiency in order to retain and expand customer base.

  8. The ABC protein turned chloride channel whose failure causes cystic fibrosis.

    Science.gov (United States)

    Gadsby, David C; Vergani, Paola; Csanády, László

    2006-03-23

    CFTR chloride channels are encoded by the gene mutated in patients with cystic fibrosis. These channels belong to the superfamily of ABC transporter ATPases. ATP-driven conformational changes, which in other ABC proteins fuel uphill substrate transport across cellular membranes, in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. New structural and biochemical information from prokaryotic ABC proteins and functional information from CFTR channels has led to a unifying mechanism explaining those ATP-driven conformational changes.

  9. A Design of ABC95 Array Computer Multi-function Interconnection Chips

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    ABC95 array computer is a multi-function network computer based on FPGA technology. A notable feature of ABC95 array computer is the support of complex interconnection, which determines that the computer must have enough I/O band and flexible communications between Pes. The authors designed the interconnecting network chips of ABC95 and realized a form of multi-function interconnection. The multi-function interconnecting network supports conflict-free access from processors to memory matrix and the MESH network of enhanced processors to processor communications. The design scheme has been proved feasible by experiment.

  10. The ABC protein turned chloride channel whose failure causes cystic fibrosis

    Science.gov (United States)

    Gadsby, David C.; Vergani, Paola; Csanády, László

    2006-03-01

    CFTR chloride channels are encoded by the gene mutated in patients with cystic fibrosis. These channels belong to the superfamily of ABC transporter ATPases. ATP-driven conformational changes, which in other ABC proteins fuel uphill substrate transport across cellular membranes, in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. New structural and biochemical information from prokaryotic ABC proteins and functional information from CFTR channels has led to a unifying mechanism explaining those ATP-driven conformational changes.

  11. Activity of the dietary flavonoid, apigenin, against multidrug-resistant tumor cells as determined by pharmacogenomics and molecular docking.

    Science.gov (United States)

    Saeed, Mohamed; Kadioglu, Onat; Khalid, Hassan; Sugimoto, Yoshikazu; Efferth, Thomas

    2015-01-01

    Apigenin is a common dietary flavonoid with considerable cytotoxic activity in vitro and in vivo. Despite many mechanistic studies, less is known about resistance factors hampering apigenin's activity. We investigated the ATP-binding cassette (ABC) transporters BCRP/ABCG2, P-glycoprotein/ABCB1 and its close relative ABCB5. Multidrug-resistant cells overexpressing these ABC transporters were not cross-resistant toward apigenin. Moreover, apigenin inhibited not only P-glycoprotein but also BCRP by increasing cellular uptake of doxorubicin and synergistic inhibition of cell viability in combination with doxorubicin or docetaxel in multidrug-resistant cells. To perform in silico molecular docking studies, we first generated homology models for human P-glycoprotein and ABCB5 based on the crystal structure of murine P-glycoprotein. Their nucleotide binding domains (NDBs) revealed the highest degrees of sequence homologies (89%-100%), indicating that ATP binding and cleavage is of crucial importance for ABC transporters. Molecular docking of apigenin bound to the NDBs of P-glycoprotein and ABCB5 in molecular docking studies. Hence, apigenin may compete with ATP for NDB-binding leading to energy depletion to fuel the transport of ABC transporter substrates. Furthermore, we performed COMPARE and hierarchical cluster analyses of transcriptome-wide mRNA expression profiles of the National Cancer Institute tumor cell line panel. Microarray-based mRNA expressions of genes of diverse biological functions (signal transduction, transcriptional regulation, ubiquitination, autophagy, metabolic activity, xenobiotic detoxification and microtubule formation) significantly predicted responsiveness of tumor cells to apigenin. In conclusion, apigenin's activity is not hampered by classical mechanisms of multidrug resistance and the inhibition of ABC transporters by apigenin indicates that apigenin may overcome multidrug resistance in otherwise refractory tumors.

  12. Formation of the productive ATP-Mg2+-bound dimer of GlcV, an ABC-ATPase from Sulfolobus solfataricus

    NARCIS (Netherlands)

    Verdon, G; Albers, SV; van Oosterwijk, N; Dijkstra, BW; Driessen, AJM; Thunnissen, AMWH; Dijkstra, Bauke W.

    2003-01-01

    The ABC-ATPase GlcV from Sulfolobus solfataricus energizes an ABC transporter mediating glucose uptake. In ABC transporters, two ABC-ATPases are believed to form a head-to-tail dimer, with both monomers contributing conserved residues to each of the two productive active sites. In contrast, isolated

  13. 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.

  14. The H-loop in the second nucleotide-binding domain of the cystic fibrosis transmembrane conductance regulator is required for efficient chloride channel closing.

    Science.gov (United States)

    Kloch, Monika; Milewski, Michał; Nurowska, Ewa; Dworakowska, Beata; Cutting, Garry R; Dołowy, Krzysztof

    2010-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a cAMP-activated chloride channel. The recent model of CFTR gating predicts that the ATP binding to both nucleotide-binding domains (NBD1 and NBD2) of CFTR is required for the opening of the channel, while the ATP hydrolysis at NBD2 induces subsequent channel closing. In most ABC proteins, efficient hydrolysis of ATP requires the presence of the invariant histidine residue within the H-loop located in the C-terminal part of the NBD. However, the contribution of the corresponding region (H-loop) of NBD2 to the CFTR channel gating has not been examined so far. Here we report that the alanine substitution of the conserved dipeptide HR motif (HR-->AA) in the H-loop of NBD2 leads to prolonged open states of CFTR channel, indicating that the H-loop is required for efficient channel closing. On the other hand, the HR-->AA substitution lead to the substantial decrease of CFTR-mediated current density (pA/pF) in transfected HEK 293 cells, as recorded in the whole-cell patch-clamp analysis. These results suggest that the H-loop of NBD2, apart from being required for CFTR channel closing, may be involved in regulating CFTR trafficking to the cell surface.

  15. THE REAL ISSUE WITH WALL DEPOSITS IN CLOSED FILTER CASSETTES - WHAT'S THE SAMPLE?

    Energy Technology Data Exchange (ETDEWEB)

    Brisson, M.

    2009-09-12

    The measurement of aerosol dusts has long been utilized to assess the exposure of workers to metals. Tools used to sample and measure aerosol dusts have gone through many transitions over the past century. In particular, there have been several different techniques used to sample for beryllium, not all of which might be expected to produce the same result. Today, beryllium samples are generally collected using filters housed in holders of several different designs, some of which are expected to produce a sample that mimics the human capacity for dust inhalation. The presence of dust on the interior walls of cassettes used to hold filters during metals sampling has been discussed in the literature for a number of metals, including beryllium, with widely varying data. It appears that even in the best designs, particulates can enter the sampling cassette and deposit on the interior walls rather than on the sampling medium. The causes are not well understood but are believed to include particle bounce, electrostatic forces, particle size, particle density, and airflow turbulence. Historically, the filter catch has been considered to be the sample, but the presence of wall deposits, and the potential that the filter catch is not representative of the exposure to the worker, puts that historical position into question. This leads to a fundamental question: What is the sample? This article reviews the background behind the issue, poses the above-mentioned question, and discusses options and a possible path forward for addressing that question.

  16. Fully Automated Data Collection Using PAM and the Development of PAM/SPACE Reversible Cassettes

    Science.gov (United States)

    Hiraki, Masahiko; Watanabe, Shokei; Chavas, Leonard M. G.; Yamada, Yusuke; Matsugaki, Naohiro; Igarashi, Noriyuki; Wakatsuki, Soichi; Fujihashi, Masahiro; Miki, Kunio; Baba, Seiki; Ueno, Go; Yamamoto, Masaki; Suzuki, Mamoru; Nakagawa, Atsushi; Watanabe, Nobuhisa; Tanaka, Isao

    2010-06-01

    To remotely control and automatically collect data in high-throughput X-ray data collection experiments, the Structural Biology Research Center at the Photon Factory (PF) developed and installed sample exchange robots PAM (PF Automated Mounting system) at PF macromolecular crystallography beamlines; BL-5A, BL-17A, AR-NW12A and AR-NE3A. We developed and installed software that manages the flow of the automated X-ray experiments; sample exchanges, loop-centering and X-ray diffraction data collection. The fully automated data collection function has been available since February 2009. To identify sample cassettes, PAM employs a two-dimensional bar code reader. New beamlines, BL-1A at the Photon Factory and BL32XU at SPring-8, are currently under construction as part of Targeted Proteins Research Program (TPRP) by the Ministry of Education, Culture, Sports, Science and Technology of Japan. However, different robots, PAM and SPACE (SPring-8 Precise Automatic Cryo-sample Exchanger), will be installed at BL-1A and BL32XU, respectively. For the convenience of the users of both facilities, pins and cassettes for PAM and SPACE are developed as part of the TPRP.

  17. Site-specific recombination in the chicken genome using Flipase recombinase-mediated cassette exchange.

    Science.gov (United States)

    Lee, Hong Jo; Lee, Hyung Chul; Kim, Young Min; Hwang, Young Sun; Park, Young Hyun; Park, Tae Sub; Han, Jae Yong

    2016-02-01

    Targeted genome recombination has been applied in diverse research fields and has a wide range of possible applications. In particular, the discovery of specific loci in the genome that support robust and ubiquitous expression of integrated genes and the development of genome-editing technology have facilitated rapid advances in various scientific areas. In this study, we produced transgenic (TG) chickens that can induce recombinase-mediated gene cassette exchange (RMCE), one of the site-specific recombination technologies, and confirmed RMCE in TG chicken-derived cells. As a result, we established TG chicken lines that have, Flipase (Flp) recognition target (FRT) pairs in the chicken genome, mediated by piggyBac transposition. The transgene integration patterns were diverse in each TG chicken line, and the integration diversity resulted in diverse levels of expression of exogenous genes in each tissue of the TG chickens. In addition, the replaced gene cassette was expressed successfully and maintained by RMCE in the FRT predominant loci of TG chicken-derived cells. These results indicate that targeted genome recombination technology with RMCE could be adaptable to TG chicken models and that the technology would be applicable to specific gene regulation by cis-element insertion and customized expression of functional proteins at predicted levels without epigenetic influence.

  18. Recent advances on host plants and expression cassettes' structure and function in plant molecular pharming.

    Science.gov (United States)

    Makhzoum, Abdullah; Benyammi, Roukia; Moustafa, Khaled; Trémouillaux-Guiller, Jocelyne

    2014-04-01

    Plant molecular pharming is a promising system to produce important recombinant proteins such as therapeutic antibodies, pharmaceuticals, enzymes, growth factors, and vaccines. The system provides an interesting alternative method to the direct extraction of proteins from inappropriate source material while offering the possibility to overcome problems related to product safety and source availability. Multiple factors including plant hosts, genes of interest, expression vector cassettes, and extraction and purification techniques play important roles in the plant molecular pharming. Plant species, as a biosynthesis platform, are a crucial factor in achieving high yields of recombinant protein in plant. The choice of recombinant gene and its expression strategy is also of great importance in ensuring a high amount of the recombinant proteins. Many studies have been conducted to improve expression, accumulation, and purification of the recombinant protein from molecular pharming systems. Re-engineered vectors and expression cassettes are also pivotal tools in enhancing gene expression at the transcription and translation level, and increasing protein accumulation, stability, retention and targeting of specific organelles. In this review, we report recent advances and strategies of plant molecular pharming while focusing on the choice of plant hosts and the role of some molecular pharming elements and approaches: promoters, codon optimization, signal sequences, and peptides used for upstream design, purification and downstream processing.

  19. Site-specific integration and tailoring of cassette design for sustainable gene transfer.

    Science.gov (United States)

    Lombardo, Angelo; Cesana, Daniela; Genovese, Pietro; Di Stefano, Bruno; Provasi, Elena; Colombo, Daniele F; Neri, Margherita; Magnani, Zulma; Cantore, Alessio; Lo Riso, Pietro; Damo, Martina; Pello, Oscar M; Holmes, Michael C; Gregory, Philip D; Gritti, Angela; Broccoli, Vania; Bonini, Chiara; Naldini, Luigi

    2011-08-21

    Integrative gene transfer methods are limited by variable transgene expression and by the consequences of random insertional mutagenesis that confound interpretation in gene-function studies and may cause adverse events in gene therapy. Site-specific integration may overcome these hurdles. Toward this goal, we studied the transcriptional and epigenetic impact of different transgene expression cassettes, targeted by engineered zinc-finger nucleases to the CCR5 and AAVS1 genomic loci of human cells. Analyses performed before and after integration defined features of the locus and cassette design that together allow robust transgene expression without detectable transcriptional perturbation of the targeted locus and its flanking genes in many cell types, including primary human lymphocytes. We thus provide a framework for sustainable gene transfer in AAVS1 that can be used for dependable genetic manipulation, neutral marking of the cell and improved safety of therapeutic applications, and demonstrate its feasibility by rapidly generating human lymphocytes and stem cells carrying targeted and benign transgene insertions.

  20. Electricity generation from cattle manure slurry by cassette-electrode microbial fuel cells.

    Science.gov (United States)

    Inoue, Kengo; Ito, Toshihiro; Kawano, Yoshihiro; Iguchi, Atsushi; Miyahara, Morio; Suzuki, Yoshihiro; Watanabe, Kazuya

    2013-11-01

    Cassette-electrode microbial fuel cells (CE-MFCs) are efficient and scalable devices for electricity production from organic waste. Previous studies have demonstrated that CE-MFCs are capable of generating electricity from artificial wastewater at relatively high efficiencies. In this study, a single-cassette CE-MFC was constructed, and its capacity for electricity generation from cattle manure suspended in water (solid to water ratio of 1:50) was examined. The CE-MFC reactor was operated in batch mode for 49 days; electricity generation became stable 2 weeks after initiating the operation. The maximum power density was measured at 16.3 W m⁻³ on day 26. Sequencing analysis of PCR-amplified 16S rRNA gene fragments obtained from the original manure and from anode biofilms suggested that Chloroflexi and Geobacteraceae were abundant in the anode biofilm (29% and 18%, respectively), whereas no Geobacteraceae sequences were detected in the original manure sample. The results of this study suggest that CE-MFCs can be used to generate electricity from water-suspended cattle manure in a scalable MFC system.