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Sample records for original bla igpro20

  1. Efficacy and Safety of a New 20% Immunoglobulin Preparation for Subcutaneous Administration, IgPro20, in Patients With Primary Immunodeficiency

    PubMed Central

    Fasano, Mary B.; Spector, Sheldon; Wasserman, Richard L.; Melamed, Isaac; Rojavin, Mikhail A.; Zenker, Othmar; Orange, Jordan S.

    2010-01-01

    Subcutaneous human IgG (SCIG) therapy in primary immunodeficiency (PID) offers sustained IgG levels throughout the dosing cycle and fewer adverse events (AEs) compared to intravenous immunoglobulin (IVIG). A phase I study showed good local tolerability of IgPro20, a new 20% liquid SCIG stabilized with L-proline. A prospective, open-label, multicenter, single-arm, phase III study evaluated the efficacy and safety of IgPro20 in patients with PID over 15 months. Forty-nine patients (5–72 years) previously treated with IVIG received weekly subcutaneous infusions of IgPro20. The mean serum IgG level was 12.5 g/L. No serious bacterial infections were reported. There were 96 nonserious infections (rate 2.76/patient per year). The rate of days missed from work/school was 2.06/patient per year, and the rate of hospitalization was 0.2/patient per year. Ninety-nine percent of AEs were mild or moderate. No serious, IgPro20-related AEs were reported. IgPro20 effectively protected patients with PID against infections and maintained serum IgG levels without causing unexpected AEs. PMID:20454851

  2. Replicon typing of plasmids carrying blaCTX-M-1 in Enterobacteriaceae of animal, environmental and human origin

    PubMed Central

    Zurfluh, Katrin; Jakobi, Gianna; Stephan, Roger; Hächler, Herbert; Nüesch-Inderbinen, Magdalena

    2014-01-01

    Objectives: The aim of this work was to determine the plasmid replicon profiles of a collection of blaCTX-M-1-positive enterobacterial strains. The isolates originated from chicken in the production pyramid, healthy food-producing animals at slaughter (chicken, calves, and pigs), chicken retail meat, environmental isolates originating from water bodies, and isolates from humans. A selection of IncI and IncN plasmids were characterized by multilocus sequence typing in order to determine their epidemiological relatedness. Methods: Transconjugants of 74 blaCTX-M-1-positive isolates were analyzed by PCR-based replicon typing and by PCR-based plasmid multilocus sequence typing. Results: The incompatibility groups detected among the blaCTX-M-1-harboring plasmids included IncI1, IncN, IncHI1B, IncF, IncFIIS, IncFIB, and IncB/O, with plasmid lineage IncI1/ST3 predominating in isolates from chicken and from humans. Lineage IncN/ST1 was detected mainly in isolates from pigs. For the first time, blaCTX-M-1 genes encoded on IncHI1 plasmids were detected in isolates from cattle and from water bodies. Conclusions: This study identifies plasmid lineages that are contributing to the dissemination of blaCTX-M-1 genes in the food chain, the environment, and humans. PMID:25400623

  3. Worldwide Diversity of Klebsiella pneumoniae That Produce β-Lactamase blaKPC-2 Gene1

    PubMed Central

    Cuzon, Gaëlle; Truong, HaVy; Villegas, Maria-Virginia; Wisell, Karin T.; Carmeli, Yehuda; Gales, Ana. C.; Navon-Venezia, Shiri; Quinn, John P.; Nordmann, Patrice

    2010-01-01

    Klebsiella pneumoniae isolates that produce carbapenemases (KPCs) are rapidly disseminating worldwide. To determine their genetic background, we investigated 16 blaKPC-2-harboring K. pneumoniae isolates from 5 countries. The isolates were multidrug resistant, possessed the blaKPC-2 gene, and differed by additional β-lactamase content. They harbored a naturally chromosome-encoded bla gene (blaSHV-1 [12.5%], blaSHV-11 [68.7%], or blaOKP-A/B [18.8%]) and several acquired and plasmid-encoded genes (blaTEM-1 [81.3%], blaCTX-M-2 [31.3%], blaCTX-M-12 [12.5%], blaCTX-M-15 [18.7%], and blaOXA-9 [37.5%]). The blaKPC-2 gene was always associated with 1 of the Tn4401 isoforms (a, b, or c). Tn4401 was inserted on different-sized plasmids that belonged to different incompatibility groups. Several blaKPC-containing K. pneumoniae clones were found: 9 different pulsotypes with 1 major (sequence type 258) and 7 minor distinct allelic profiles. Different clones harboring different plasmids but having identical genetic structure, Tn4401, could be at the origin of the worldwide spread of this emerging resistance gene. PMID:20735917

  4. ISCR2, Another Vehicle for blaVEB Gene Acquisition▿

    PubMed Central

    Poirel, Laurent; Mugnier, Pauline D.; Toleman, Mark A.; Walsh, Timothy R.; Rapoport, Melina J.; Petroni, Alejandro; Nordmann, Patrice

    2009-01-01

    The expanded-spectrum β-lactamase (ESBL) gene blaVEB-1, identified worldwide in Enterobacteriaceae and Pseudomonas aeruginosa, is associated with either class 1 integrons or repeated elements. We report here the first association of blaVEB-1a with the insertion sequence ISCR2 in six Acinetobacter species isolates recovered from Argentina. That genetic structure was likely at the origin of the mobilization of this ESBL gene. PMID:19704129

  5. Escherichia coli of sequence type 3835 carrying bla NDM-1, bla CTX-M-15, bla CMY-42 and bla SHV-12.

    PubMed

    Feng, Yu; Yang, Ping; Xie, Yi; Wang, Xiaohui; McNally, Alan; Zong, Zhiyong

    2015-01-01

    New Delhi metallo-β-lactamase (NDM) represents a serious challenge for treatment and public health. A carbapenem-resistant Escherichia coli clinical strain WCHEC13-8 was subjected to antimicrobial susceptibility tests, whole genome sequencing and conjugation experiments. It was resistant to imipenem (MIC, >256 μg/ml) and meropenem (MIC, 128 μg/ml) and belonged to ST3835. bla NDM-1 was the only carbapenemase gene detected. Strain WCHEC13-8 also had a plasmid-borne AmpC gene (bla CMY-42) and two extended-spectrum β-lactamase genes (bla CTX-M-15 and bla SHV-12). bla NDM-1 and bla SHV-12 were carried by a 54-kb IncX3 self-transmissible plasmid, which is identical to plasmid pNDM-HF727 from Enterobacter cloacae. bla CMY-42 was carried by a 64-kb IncI1 plasmid and bla CTX-M-15 was located on a 141-kb plasmid with multiple F replicons (replicon type: F36:A4:B1). bla CMY-42 was in a complicated context and the mobilisation of bla CMY-42 was due to the transposition of ISEcp1 by misidentifying its right-end boundary. Genetic context of bla NDM-1 in strain WCHEC13-8 was closely related to those on IncX3 plasmids in various Enterobacteriaceae species in China. In conclusion, a multidrug-resistant ST3835 E. coli clinical strain carrying bla NDM-1, bla CTX-M-15, bla CMY-42 and bla SHV-12 was identified. IncX3 plasmids may be making a significant contribution to the dissemination of bla NDM among Enterobacteriaceae in China. PMID:26194736

  6. Dissemination of imipenem-resistant Acinetobacter baumannii with new plasmid-borne blaOXA-72 in Taiwan

    PubMed Central

    2013-01-01

    Background The systemic surveillance of imipenem-resistant Acinetobacter baumannii (IRAB) from multicenters in Taiwan revealed the emergence of isolates with blaOXA-72. This study described their genetic makeup, mechanism of spread, and contribution to carbapenem resistance. Methods Two hundred and ninety-one non-repetitive isolates of A. baumannii were collected from 10 teaching hospitals from different geographical regions in Taiwan from June 2007 to September 2007. Minimal inhibitory concentrations (MICs) were determined by agar dilution. Clonality was determined by pulsed-field gel electrophoresis. Plasmid was extracted and digested by restriction enzymes, and subsequently analyzed by electrophoresis and Southern blot for blaOXA-72. The flanking regions of blaOXA-72 were determined by inverse PCR. The contribution of blaOXA-72 to imipenem MIC was determined by transforming plasmids carrying blaOXA-72 into imipenem-susceptible A. baumannii. Results Among 142 IRAB in Taiwan, 27 harbored blaOXA-72; 22 originated from Southern Taiwan, 5 from Central Taiwan, and none from Northern Taiwan. There were two major clones. The blaOXA-72 was identified in the plasmids of all isolates. Two genetic structures flanking plasmid-borne blaOXA-72 were identified and shared identical sequences in certain regions; the one described in previous literature was present in only one isolate, and the new one was present in the remaining isolates. Introduction of blaOXA-72 resulted in an increase of imipenem MIC in the transformants. The overexpression of blaOXA-72 mRNA in response to imipenem further supported the contribution of blaOXA-72. Conclusions In conclusion, isolates with new plasmid-borne blaOXA-72 were found to be disseminated successfully in Southern Taiwan. The spread of the resistance gene depended on clonal spread and dissemination of a new plasmid. BlaOXA-72 in these isolates directly led to their imipenem-resistance. PMID:23849336

  7. Novel structure of cockroach allergen Bla g 1 has implications for allergenicity and exposure assessment

    PubMed Central

    Mueller, Geoffrey A.; Pedersen, Lars C.; Lih, Fred B.; Glesner, Jill; Moon, Andrea F.; Chapman, Martin D.; Tomer, Kenneth B.; London, Robert E.; Pomés, Anna

    2013-01-01

    Background Sensitization to cockroach allergens is a major risk factor for asthma. The cockroach allergen Bla g 1 has multiple repeats of ~100 amino acids, but the fold of the protein and the biological function are unknown. Objective To determine the structure of Bla g 1, investigate the implications for allergic disease, and standardize cockroach exposure assays. Methods Natural Bla g 1 and recombinant constructs were compared by ELISA using specific murine IgG and human IgE. The structure of Bla g 1 was determined by X-ray crystallography. Mass spectrometry and NMR were utilized to examine ligand-binding properties of the allergen. Results The structure of a recombinant Bla g 1 construct with comparable IgE and IgG reactivity to the natural allergen was solved by X-ray crystallography. The Bla g 1 repeat forms a novel fold with 6 helices. Two repeats encapsulate a large and nearly spherical hydrophobic cavity, defining the basic structural unit. Lipids in the cavity varied depending on the allergen origin. Palmitic, oleic and stearic acids were associated with nBla g 1 from cockroach frass. One Unit of Bla g 1 was equivalent to 104 ng of allergen. Conclusions Bla g 1 has a novel fold with a capacity to bind various lipids, which suggests a digestive function associated with non-specific transport of lipid molecules in cockroaches. Defining the basic structural unit of Bla g 1 facilitates the standardization of assays in absolute units for the assessment of environmental allergen exposure. PMID:23915714

  8. Characterisation of IncA/C2 plasmids carrying an In416-like integron with the blaVIM-19 gene from Klebsiella pneumoniae ST383 of Greek origin.

    PubMed

    Papagiannitsis, Costas C; Dolejska, Monika; Izdebski, Radosław; Giakkoupi, Panagiota; Skálová, Anna; Chudějová, Kateřina; Dobiasova, Hana; Vatopoulos, Alkiviadis C; Derde, Lennie P G; Bonten, Marc J M; Gniadkowski, Marek; Hrabák, Jaroslav

    2016-02-01

    The complete nucleotide sequences of three multidrug resistance (MDR) IncA/C-like plasmids from Enterobacteriaceae isolates carrying the VIM-type carbapenemase-encoding integrons In4863 (blaVIM-19-aacA7-dfrA1-ΔaadA1-smr2) or In4873 (blaVIM-1-aacA7-dfrA1-ΔaadA1-smr2) were determined, which are the first In416-like elements identified in Greece. Plasmids pKP-Gr642 and pKP-Gr8143 were from Klebsiella pneumoniae ST383 isolates, whereas plasmid pEcl-Gr4873 was from an Enterobacter cloacae ST88 isolate. Sequencing showed that pKP-Gr642 (162787bp) and pKP-Gr8143 (154395bp) consisted of the type 1 IncA/C2 conserved backbone, the blaCMY-2-like gene-containing region, and the ARI-B (with the sul2 gene) and ARI-A (with a class 1 integron) resistance islands, like the plasmid pUMNK88_161 from the USA. The third plasmid, pEcl-Gr4873 (153958bp), exhibited extensive similarity with the type 2 IncA/C2 plasmid pR55 from France. pEcl-Gr4873 carried only one resistance island of a hybrid transposon structure inserted in a different location to ARI-A in type 1 A/C2 plasmids. In all three plasmids, the In416-like integrons In4863 or In4873 were identified within non-identical class II transposon structures. All three In416-like-carrying regions presented significant similarities with the MDR region of the IncA/C2 plasmid pCC416 from Italy, carrying the prototype In416 integron (blaVIM-4-aacA7-dfrA1-ΔaadA1-smr2). These findings provided the basis for speculations regarding the evolution of IncA/C2 plasmids with In416-like integrons, and confirmed the rapid evolution of some IncA/C2 plasmid lineages. Considering the broad host range of IncA/C2 molecules, it seems that pKP-Gr642, pKP-Gr8143 and pEcl-Gr4873 plasmids might support the diffusion of In416-like integrons among Enterobacteriaceae. PMID:26795022

  9. Molecular Characterization of blaNDM-5 Carried on an IncFII Plasmid in an Escherichia coli Isolate from a Nontraveler Patient in Spain

    PubMed Central

    Pitart, Cristina; Solé, Mar; Román, Angely; Moreno, Asunción; Marco, Francesc

    2014-01-01

    A carbapenem-resistant Escherichia coli isolate (sequence type 448 [ST448]) was recovered from a urine culture of a female patient with no recent record of traveling. PCR screening identified the presence of blaNDM-5, blaTEM-1, blaOXA-1, blaCMY-42, and rmtB. blaNDM-5 was carried in a conjugative IncFII-type plasmid (90 kb) together with blaTEM-1 and rmtB. The genetic environment of blaNDM-5 showed a structure similar to those of pMC-NDM and pGUE-NDM, identified in Poland and France in E. coli of African and Indian origin, respectively. PMID:25313215

  10. Novel Conjugative Plasmid from Escherichia coli of Swine Origin That Coharbors the Multiresistance Gene cfr and the Extended-Spectrum-β-Lactamase Gene blaCTX-M-14b

    PubMed Central

    Zhang, Wan-Jiang; Wang, Xiu-Mei; Dai, Lei; Hua, Xin; Dong, Zhimin

    2014-01-01

    Two porcine Escherichia coli isolates harbored the cfr gene on conjugative plasmids of 38,405 bp (pGXEC6) and 41,646 bp (pGXEC3). In these two plasmids, the cfr gene was located within a 4,612-bp region containing a tnpA-IS26-cfr-IS26-Δhyp element. Plasmid pGXEC3 was almost identical to pGXEC6 except for a 3,235-bp ISEcp1-blaCTX-M-14b insertion. The colocation of the multiresistance cfr gene with an extended-spectrum-β-lactamase gene on a conjugative plasmid may support the dissemination of these genes by coselection. PMID:25421479

  11. Biochemical Characterization of PER-2 and Genetic Environment of blaPER-2▿

    PubMed Central

    Power, Pablo; Di Conza, José; Rodríguez, María Margarita; Ghiglione, Bárbara; Ayala, Juan A.; Casellas, José María; Radice, Marcela; Gutkind, Gabriel

    2007-01-01

    PER-2 was the first detected and the second most prevalent extended-spectrum β-lactamase in clinical pathogens isolated in Argentina and was also reported only in other South American countries. Citrobacter freundii 33587 was isolated in 1999 in Buenos Aires and was resistant to all tested β-lactams except cephamycins and carbapenems. The strain produced both plasmid-borne TEM-1 and PER-2 (pI 5.4), which could be transferred by conjugation. By PCR screening, thermal asymmetric interlaced PCR, and DNA sequencing, we detected an ISPa12/IS1387a insertion sequence upstream of blaPER-2, previously reported as also being associated with blaPER-1. The presence of similar structures upstream of blaPER-1 and blaPER-2 suggests a common origin and mobilization. Compared to blaPER-1 genes, an additional putative promoter for blaPER-2 was found. PER-2 kinetic analysis showed its high hydrolysis efficiencies toward both CTX and CAZ (kcat/Km, 0.76 and 0.43 μM−1·s−1, respectively). PMID:17438050

  12. Genetic Structure Associated with blaOXA-18, Encoding a Clavulanic Acid-Inhibited Extended-Spectrum Oxacillinase▿

    PubMed Central

    Naas, Thierry; Namdari, Fatemeh; Bogaerts, Pierre; Huang, Te-Din; Glupczynski, Youri; Nordmann, Patrice

    2008-01-01

    The genetic environment of the blaOXA-18 gene encoding a peculiar clavulanic acid-inhibitable Ambler class D extended-spectrum β-lactamase was determined from the prototype OXA-18-producing Pseudomonas aeruginosa MUS clinical isolate. An 8.2-kb genomic DNA fragment containing blaOXA-18 was cloned from P. aeruginosa MUS. Although most oxacillinases are located in integrons, blaOXA-18 lacked gene cassette-specific features. It was bracketed by two duplicated sequences containing ISCR19, a novel insertion sequence of the ISCR family of mobile elements; ΔintI1, a truncated integrase gene; and a truncated Δaac6′-Ib gene cassette. It is likely that ISCR19 was at the origin of the blaOXA-18 gene mobilization by a rolling-circle transposition event followed by homologous recombination. Furthermore, analysis of the cloned genomic DNA fragment revealed the presence of the integron-containing blaOXA-20 gene. Concomitantly, three P. aeruginosa clinical isolates, displaying a synergy image as determined by double-disk diffusion tests on cloxacillin-containing plates, were isolated from three patients hospitalized in different wards over a 9-month period at the Saint-Luc University hospital (Brussels, Belgium). These isolates were positive by PCR for blaOXA-18 and blaOXA-20 genes, genetically related to P. aeruginosa MUS as determined by pulsed-field gel electrophoresis, and carried the same blaOXA-18/blaOXA-20-associated genetic structures. This report characterized the genetic elements likely at the origin of blaOXA-18 gene mobilization in P. aeruginosa and suggests the spread of oxacillin-type extended-spectrum β-lactamases in P. aeruginosa at the Saint-Luc University hospital of Brussels, Belgium. PMID:18663027

  13. First occurrence of blaOXA-58 in Acinetobacter baumannii isolated from a clinical sample in Southern Brazil

    PubMed Central

    de Souza Gusatti, Carolina; Bertholdo, Lauren Martins; Otton, Letícia Muner; Marchetti, Desirée Padilha; Ferreira, Alessandra Einsfeld; Corção, Gertrudes

    2012-01-01

    This is the first report of an Acinetobacter baumannii from clinical origin carrying the blaOXA-58 gene in Brazil. The isolate included in this study was from a patient during an outbreak in Porto Alegre, RS, Southern Brazil, in 2007. It was resistant to most of the beta-lactams tested, it has also the blaOXA-65 gene and the ISAbal sequence located upstream to both blaOXA genes detected and it has a MIC of imipenem of 64 μg/mL. PMID:24031824

  14. Prevalence of blaNDM, blaPER, blaVEB, blaIMP, and blaVIM Genes among Acinetobacter baumannii Isolated from Two Hospitals of Tehran, Iran

    PubMed Central

    Fallah, Fatemeh; Noori, Maryam; Goudarzi, Hossein; Karimi, Abdollah; Erfanimanesh, Soroor; Alimehr, Shadi

    2014-01-01

    Background and Objectives. The aim of this study was to determine the frequency of blaNDM, blaPER, blaVEB, blaIMP, and blaVIM type genes among A. baumannii isolates from hospitalized patients in two hospitals in Tehran, Iran. Patients and Methods. Antibiotic susceptibility tests were performed by Kirby-Bauer disc diffusion and Broth microdilution methods. The frequency of MBL (metallo-beta-lactamase) and ESBL (extended-spectrum-beta-lactamase) producers was evaluated by CDDT. The β-lactamases genes were detected by PCR and sequencing methods. Results. The resistance of A. baumannii isolates against tested antibiotics was as follows: 103 (95.4%) to ceftazidime, 108 (100%) to cefotaxime, 105 (95.7%) to cefepime, 99 (91.7%) to imipenem, 99 (91.7%) to meropenem, 87 (80.6%) to amikacin, 105 (97.2%) to piperacillin, 100 (92.6%) to ciprofloxacin, 103 (95.4%) to piperacillin/tazobactam, 44 (40.7%) to gentamicin, 106 (98.1%) to ampicillin/sulbactam, 106 (98.1%) to co-trimoxazole, 87 (80.6%) to tetracycline, and 1 (1.8%) to colistin. Using combined disk diffusion test, 91 (84.2%) and 86 (86.86%) were ESBL and MBL producers, respectively. The prevalence of blaPER-1, blaVEB-1, blaIMP-1, and blaVIM-1 genes was 71 (78.03%), 36 (39.5%), 3 (3.48%), and 15 (17.44%), respectively. Conclusions. The prevalence of ESBLs and MBLs-producing A. baumannii strains detected in this study is a major concern and highlights the need of infection control measures. PMID:25133013

  15. Identification of blaOXA-51, blaOXA-58, blaDIM-1 and blaVIM carbapenemase genes in hospital enterobacteriaceae isolates from Sierra Leone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We describe the results of a molecular epidemiological survey of 15 carbapenemase-encoding genes from a recent collection of clinical isolates. The most salient findings revealed that (i) 60% of the isolates harbored multiple carbapenemase genes, (ii) the blaDIM-1 gene that has only been reported in...

  16. Co-occurrence of blaNDM-1 with blaOXA-23 or blaOXA-58 in clinical multidrug-resistant Acinetobacter baumannii isolates in Algeria.

    PubMed

    Ramoul, Abir; Loucif, Lotfi; Bakour, Sofiane; Amiri, Sabrina; Dekhil, Mazouz; Rolain, Jean-Marc

    2016-09-01

    The aim of this study was to characterise the mechanisms of carbapenem resistance in Acinetobacter baumannii strains isolated in an Algerian hospital. A total of 43 imipenem-resistant A. baumannii clinical isolates collected between 2010 and 2013 were identified using API 20NE and were confirmed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antibiotic susceptibility testing was performed by the disk diffusion and Etest methods. Carbapenemase activity was detected using microbiological tests and PCR. Genetic transfer of the blaNDM-1 gene was performed by conjugation using sodium azide-resistant Escherichia coli J53 as recipient strain. Clonal relationships were studied by multilocus sequence typing (MLST) using partial sequences of the csuE and blaOXA-51 genes. All 43 A. baumannii isolates were resistant to imipenem with high minimum inhibitory concentrations (MICs) (>32μg/mL). The strains harboured blaOXA-23, blaNDM-1, blaOXA-58 and/or blaOXA-24 genes. Co-existence of blaNDM-1 and blaOXA-23 or blaOXA-58 was detected in two isolates and one isolate, respectively. NDM-1 plasmid transfer to E. coli J53 was successful only for one of the three strains harbouring both blaNDM-1 and blaOXA-23 or blaOXA-58. The phylogenetic tree obtained from concatenation of the partial sequences of csuE and blaOXA-51 showed that there was no genetic relationship between the isolates and the blaNDM-1 resistance gene. Here we report for the first time the co-occurrence of blaNDM-1 along with blaOXA-23 or blaOXA-58 in recent clinical isolates of A. baumannii from Northeast Algeria. These findings re-emphasise the dissemination and rapid spread of blaNDM-1 carbapenemase genes in multidrug-resistant clinical A. baumannii isolates in Algeria. PMID:27530856

  17. Mechanisms Involved in Acquisition of blaNDM Genes by IncA/C2 and IncFIIY Plasmids.

    PubMed

    Wailan, Alexander M; Sidjabat, Hanna E; Yam, Wan Keat; Alikhan, Nabil-Fareed; Petty, Nicola K; Sartor, Anna L; Williamson, Deborah A; Forde, Brian M; Schembri, Mark A; Beatson, Scott A; Paterson, David L; Walsh, Timothy R; Partridge, Sally R

    2016-07-01

    blaNDM genes confer carbapenem resistance and have been identified on transferable plasmids belonging to different incompatibility (Inc) groups. Here we present the complete sequences of four plasmids carrying a blaNDM gene, pKP1-NDM-1, pEC2-NDM-3, pECL3-NDM-1, and pEC4-NDM-6, from four clinical samples originating from four different patients. Different plasmids carry segments that align to different parts of the blaNDM region found on Acinetobacter plasmids. pKP1-NDM-1 and pEC2-NDM-3, from Klebsiella pneumoniae and Escherichia coli, respectively, were identified as type 1 IncA/C2 plasmids with almost identical backbones. Different regions carrying blaNDM are inserted in different locations in the antibiotic resistance island known as ARI-A, and ISCR1 may have been involved in the acquisition of blaNDM-3 by pEC2-NDM-3. pECL3-NDM-1 and pEC4-NDM-6, from Enterobacter cloacae and E. coli, respectively, have similar IncFIIY backbones, but different regions carrying blaNDM are found in different locations. Tn3-derived inverted-repeat transposable elements (TIME) appear to have been involved in the acquisition of blaNDM-6 by pEC4-NDM-6 and the rmtC 16S rRNA methylase gene by IncFIIY plasmids. Characterization of these plasmids further demonstrates that even very closely related plasmids may have acquired blaNDM genes by different mechanisms. These findings also illustrate the complex relationships between antimicrobial resistance genes, transposable elements, and plasmids and provide insights into the possible routes for transmission of blaNDM genes among species of the Enterobacteriaceae family. PMID:27114281

  18. Citrobacter freundii carrying blaKPC-2 and blaNDM-1: characterization by whole genome sequencing

    PubMed Central

    Wu, Wenjing; Espedido, Björn; Feng, Yu; Zong, Zhiyong

    2016-01-01

    A carbapenem-resistant Citrobacter freundii strain WCHCF65 was recovered from hospital sewage and was characterized by genome sequencing and conjugation experiments. The strain carried nine genes encoding β-lactamases including two carbapenemase genes, blaNDM-1 and blaKPC-2. blaNDM-1 was carried on an IncX3 plasmid, which was identical to a plasmid found in a local Escherichia coli, suggesting interspecies horizontal transfer. blaKPC-2 was bracketed by two copies of insertion sequence ISKpn19, which could form a composite transposon with the potential to mobilize blaKPC-2, on a new type of plasmid. The coexistence of blaNDM-1 and blaKPC-2 conferred higher levels of resistance to carbapenems compared with blaNDM-1 or blaKPC-2 alone. The coexistence of these carbapenemase genes, on two different plasmids, in one strain may allow new genetic platforms to be generated to mediate their spread. PMID:27465241

  19. Characterization of the blaKPC-2 and blaKPC-3 genes and the novel blaKPC-15 gene in Klebsiella pneumoniae.

    PubMed

    Wang, Dongguo; Hou, Wei; Chen, Jiayu; Mou, Yonghua; Yang, Linjun; Yang, Liqin; Sun, Xiulian; Chen, Meiyun

    2014-07-01

    Three Klebsiella pneumoniae isolates exhibiting high-level resistance to carbapenem were analysed by PCR, PFGE, gene mapping, plasmid conjugation and Southern blot hybridization using a blaKPC probe. In addition to the frequently reported blaKPC-2 and blaKPC-3 genes, a novel blaKPC-15 gene was identified in one of the isolates. The results of plasmid analysis and Southern blot hybridization revealed that the three blaKPC genes were located on transferable plasmids exhibiting three different patterns. The patterns A, B and C were observed in the genetic makeup of each individual plasmid, and all three structures contained ISKpn6-like and ISKpn8 transposons. The results of the gene mapping and hybridization experiments performed with the blaKPC probe demonstrated that the plasmids harboured the three genes at approximately the 85.0, 54.0 and 73.0 kb positions. The study concluded that carbapenem resistance in the three isolates was primarily due to the production of carbapenem-hydrolysing β-lactamase. PMID:24713357

  20. Antigenic Determinants of the Bilobal Cockroach Allergen Bla g 2.

    PubMed

    Woodfolk, Judith A; Glesner, Jill; Wright, Paul W; Kepley, Christopher L; Li, Mi; Himly, Martin; Muehling, Lyndsey M; Gustchina, Alla; Wlodawer, Alexander; Chapman, Martin D; Pomés, Anna

    2016-01-29

    Bla g 2 is a major indoor cockroach allergen associated with the development of asthma. Antigenic determinants on Bla g 2 were analyzed by mutagenesis based on the structure of the allergen alone and in complex with monoclonal antibodies that interfere with IgE antibody binding. The structural analysis revealed mechanisms of allergen-antibody recognition through cation-π interactions. Single and multiple Bla g 2 mutants were expressed in Pichia pastoris and purified. The triple mutant K132A/K251A/F162Y showed an ∼100-fold reduced capacity to bind IgE, while preserving the native molecular fold, as proven by x-ray crystallography. This mutant was still able to induce mast cell release. T-cell responses were assessed by analyzing Th1/Th2 cytokine production and the CD4(+) T-cell phenotype in peripheral blood mononuclear cell cultures. Although T-cell activating capacity was similar for the KKF mutant and Bla g 2 based on CD25 expression, the KKF mutant was a weaker inducer of the Th2 cytokine IL-13. Furthermore, this mutant induced IL-10 from a non-T-cell source at higher levels that those induced by Bla g 2. Our findings demonstrate that a rational design of site-directed mutagenesis was effective in producing a mutant with only 3 amino acid substitutions that maintained the same fold as wild type Bla g 2. These residues, which were involved in IgE antibody binding, endowed Bla g 2 with a T-cell modulatory capacity. The antigenic analysis of Bla g 2 will be useful for the subsequent development of recombinant allergen vaccines. PMID:26644466

  1. Molecular Epidemiology and Genetic Characteristics of Various blaPER Genes in Shanghai, China.

    PubMed

    Xie, Lianyan; Wu, Jun; Zhang, Fangfang; Han, Lizhong; Guo, Xiaokui; Ni, Yuxing; Sun, Jingyong

    2016-06-01

    We describe the genetic characteristics and possible transmission mechanism of blaPER in 25 clinical Gram-negative bacilli in Shanghai. blaPER, including blaPER-1, blaPER-3, and blaPER-4, was located chromosomally or in different plasmids. Tn1213 harboring blaPER-1 was first identified in two Proteus mirabilis isolates in China. The other blaPER variants were preceded by an ISCR1 element inside the complex class 1 integron associated with IS26, Tn21, Tn1696, and a miniature inverted-repeat transposable element. PMID:27067315

  2. Presence of blaPER-1 and blaVEB-1 beta-lactamase genes among isolates of Pseudomonas aeruginosa from South West of Iran.

    PubMed

    Davodian, Elham; Sadeghifard, Nourkhoda; Ghasemian, Abdolmajid; Noorbakhsh, Samileh

    2016-09-01

    Pseudomonas aeruginosa isolates have acquired resistance to antibiotics such as novel beta-lactams. The aim of this study was to investigate the blaPER-1, blaVEB-1, and blaPSE-1 genes among isolates of P. aeruginosa among intensive care unit (ICU) patients. Sixty-five isolates were collected. The antibiotic susceptibility testing and combined disk tests were performed to detect the isolates producing extended spectrum beta-lactamases (ESBLs) among ceftazidime-resistant isolates. Polymerase chain reaction (PCR) amplification of blaPER-1, blaVEB-1, and blaPSE-1 genes was conducted. Ten (15.3%) isolates were ESBL-positive, of which 40% (n=4) belonged to males and 60% (n=6) were collected from females. Moreover, two and one isolates harbored blaPER-1 and blaVEB-1 genes, respectively. PMID:26944896

  3. Biochemical and Structural Characterization of Mycobacterium tuberculosis β-Lactamase (BlaC) with the Carbapenems Ertapenem and Doripenem

    PubMed Central

    Tremblay, Lee W.; Fan, Fan; Blanchard, John S

    2010-01-01

    Despite the enormous success of β-lactams as broad-spectrum antibacterials, they have never been widely used for the treatment of TB due to intrinsic resistance that is caused by the presence of a chromosomally-encoded gene (blaC) in Mycobacterium tuberculosis. Our previous studies of TB BlaC revealed that this enzyme is an extremely broad-spectrum β-lactamase hydrolyzing all β-lactam classes. Carbapenems are slow substrates that acylate the enzyme but are only slowly deacylated and can therefore act also as potent inhibitors of BlaC. We carried out the in vitro characterization of doripenem and ertapenem with BlaC. A steady-state kinetic burst was observed with both compounds with magnitudes proportional to the concentration of BlaC used. The results show apparent Km and kcat values of 0.18 µM and 0.016 min−1 for doripenem and 0.18 µM and 0.017 min−1 for ertapenem. FTICR mass spectrometry demonstrated that the doripenem and ertapenem acyl-enzyme complexes remain stable over a time period of 90 min. The BlaC-doripenem covalent complex obtained after 90 minutes of soaking was solved to 2.2 Å, while the BlaC-ertapenem complex obtained after a 90 minute soak was solved to 2.0 Å. The 1.3 Å diffraction data from a 10 minute ertapenem-soaked crystal revealed an isomerization occurring in the BlaC-ertapenem adduct in which the original Δ2 pyrroline ring was tautomerized to generate the Δ1 pyrroline ring. The isomerization leads to the flipping of the carbapenem-hydroxyethyl group to hydrogen bond to the carboxyl O2 of Glu166. The hydroxyethyl flip results in both decreased basicity of Glu166 and in a significant increase in the distance between the carboxyl O2 of Glu166 and the catalytic water molecule, slowing hydrolysis. PMID:20353175

  4. Identification of plasmid- and integron-borne blaIMP-1 and blaIMP-10 in clinical isolates of Serratia marcescens.

    PubMed

    Hu, Zhuting; Zhao, Wei-Hua

    2009-02-01

    The emergence of carbapenem-hydrolysing metallo-beta-lactamases (MBLs) is a serious threat to the clinical utility of carbapenems. This study identified plasmid- and integron-borne bla(IMP-1) and bla(IMP-10) in clinical isolates of Serratia marcescens. The bla(IMP-1) and bla(IMP-10) gene cassettes were carried by a class 1 integron and followed by the aac(6')-IIc gene cassette. The bla(IMP-1) and bla(IMP-10) gene cassettes were preceded by a weak P(ant) promoter, TGGACA(N)(17)TAAGCT, and an inactive P2 promoter, TTGTTA(N)(14)TACAGT. These genes were easily transferred to Escherichia coli by conjugation and transformation, indicating that they are located on transferable plasmids. Due to the acquisition of bla(IMP-1), the susceptibility of E. coli transconjugants to imipenem, meropenem, panipenem and biapenem decreased by 32-, 256-, 64- and 128-fold, respectively. In comparison, after gaining bla(IMP-10), the susceptibility of E. coli transconjugants to the four carbapenems decreased by 64-, 2048-, 256- and 64-fold, respectively. Strains harbouring bla(IMP-10) showed higher-level resistance to imipenem, meropenem and panipenem than the strains harbouring bla(IMP-1), although the nucleotide sequences of the class 1 integrons carrying bla(IMP-10) and bla(IMP-1) were identical except for a single point mutation. PMID:19141739

  5. Detection of blaSPM-1, blaKPC, blaTEM and blaCTX-M genes in isolates of Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella spp. from cancer patients with healthcare-associated infections.

    PubMed

    Jácome, Paula Regina Luna de Araújo; Alves, Lílian Rodrigues; Jácome-Júnior, Agenor Tavares; Silva, Maria Jesuíta Bezerra da; Lima, Jailton Lobo da Costa; Araújo, Paulo Sérgio Ramos; Lopes, Ana Catarina S; Maciel, Maria Amélia Vieira

    2016-07-01

    Pseudomonas aeruginosa, Acinetobacter spp. and Klebsiella spp. are three of the pathogens most frequently involved in infections of cancer patients, and the production of β -lactamases is a major mechanism of resistance due to its wide diversity of existing enzymes. Therefore, the aim of the present study was to investigate the microbiological profile and data related to patients and infections, and to search for β -lactamase genes in bacterial isolates from hospitalized cancer patients in a hospital in Recife, Pernambuco, Brazil. A total of 169 isolates were recovered between 2012 and 2014, of which 58 were P. aeruginosa, 36 were Acinetobacter spp. and 75 were Klebsiella spp. A high percentage of carbapenem resistance was observed in P. aeruginosa and Acinetobacter spp. Among the carbapenem-resistant bacteria, the blaSPM-1 gene was detected in P. aeruginosa (35.5 %) and Acinetobacter spp. (3.8 %), while blaKPC was detected in P. aeruginosa (25.8 %) only. Among the third- and fourth-generation cephalosporin-resistant strains, in Klebsiella spp. we detected the genes blaTEM (30.6 %), blaCTX-M (58.3 %) and blaKPC (5.6 %), and in Acinetobacter spp. only blaTEM (25.9 %). This the first report of an Acinetobacter baumannii blaSPM-1 gene carrier that has been isolated in Brazil. The most frequent cancer types were bowel tumour [14.8 %; 95 % confidence interval (CI95 %) 9.8-21.1 %], breast cancer (13.6 %; CI95 % 8.8-19.7 %) and prostate cancer (11.2%; CI95 % 6.9-17.0 %). These results therefore provide knowledge of susceptibility profile and resistance mechanisms and thus can contribute to the strategic formulation of hospital infection control plans and the rational use of antimicrobials, reducing mortality from infection levels in cancer patients. PMID:27217349

  6. Wide Dissemination of Pseudomonas aeruginosa Producing β-Lactamase blaKPC-2 Gene in Colombia▿

    PubMed Central

    Cuzon, Gaelle; Naas, Thierry; Villegas, Maria-Virginia; Correa, Adriana; Quinn, John P.; Nordmann, Patrice

    2011-01-01

    Ten blaKPC-2-harboring Pseudomonas aeruginosa isolates from hospitals located in five different Colombian cities have been characterized. Isolates were multidrug resistant, belonged to five different pulsotypes, and possessed naturally chromosome-encoded blaAmpC and blaOXA-50 genes and the acquired blaKPC-2 gene. In most cases, the blaKPC-2 genes were carried by plasmids of different sizes and were associated with Tn4401b or a new structure containing only part of the Tn4401 sequence. This study revealed that several clones of P. aeruginosa producing blaKPC-2 are disseminating in Colombia. PMID:21844315

  7. High Rate of Mobilization for blaCTX-Ms

    PubMed Central

    Reik, Rebecca A.; Jacobs, Stephen D.; Medina, Mónica; Meyer, Matthew P.; McGowan, John E.; Tenover, Fred C.

    2008-01-01

    We constructed a phylogenetic analysis of class A β-lactamases and found that the blaCTX-Ms have been mobilized to plasmids ≈10 times more frequently than other class A β-lactamases. We also found that the blaCTX-Ms are descended from a common ancestor that was incorporated in ancient times into the chromosome of the ancestor of Kluyvera species through horizontal transfer. Considerable sequence divergence has occurred among the descendents of that ancestral gene sequence since that gene was inserted. That divergence has mainly occurred in the presence of purifying selection, which indicates a slow rate of evolution for blaCTX-Ms in the pre–antimicrobial drug era. PMID:18325257

  8. Two Multiplex Real-Time PCR Assays to Detect and Differentiate Acinetobacter baumannii and Non- baumannii Acinetobacter spp. Carrying blaNDM, blaOXA-23-Like, blaOXA-40-Like, blaOXA-51-Like, and blaOXA-58-Like Genes.

    PubMed

    Yang, Qiu; Rui, Yongyu

    2016-01-01

    Nosocomial infections caused by Acinetobacter spp. resistant to carbapenems are increasingly reported worldwide. Carbapenem-resistant Acinetobacter (CRA) is becoming a serious concern with increasing patient morbidity, mortality, and lengths of hospital stay. Therefore, the rapid detection of CRA is essential for epidemiological surveillance. Polymerase chain reaction (PCR) has been extensively used for the rapid identification of most pathogens. In this study, we have developed two multiplex real-time PCR assays to detect and differentiate A. baumannii and non-A. baumannii Acinetobacter spp, and common carbapenemase genes, including blaNDM, blaOXA-23-like, blaOXA-40-like, blaOXA-51-like, and blaOXA-58-like. We demonstrate the potential utility of these assays for the direct detection of blaNDM-, blaOXA-23-like-, blaOXA-40-like-, blaOXA-51-like-, and blaOXA-58-like-positive CRA in clinical specimens. Primers were specifically designed, and two multiplex real-time PCR assays were developed: multiplex real-time PCR assay1 for the detection of Acinetobacter baumannii 16S-23S rRNA internal transcribed spacer sequence, the Acinetobacter recA gene, and class-B-metalloenzyme-encoding gene blaNDM; and multiplex real-time PCR assay2 to detect class-D-oxacillinase-encoding genes (blaOXA-23-like, blaOXA-40-like, blaOXA-51-like,and blaOXA-58-like). The assays were performed on an ABI Prism 7500 FAST Real-Time PCR System. CRA isolates were used to compare the assays with conventional PCR and sequencing. Known amounts of CRA cells were added to sputum and fecal specimens and used to test the multiplex real-time PCR assays. The results for target and nontarget amplification showed that the multiplex real-time PCR assays were specific, the limit of detection for each target was 10 copies per 20 μL reaction volume, the assays were linear over six log dilutions of the target genes (r2 > 0.99), and the Ct values of the coefficients of variation for intra- and interassay

  9. Two Multiplex Real-Time PCR Assays to Detect and Differentiate Acinetobacter baumannii and Non- baumannii Acinetobacter spp. Carrying blaNDM, blaOXA-23-Like, blaOXA-40-Like, blaOXA-51-Like, and blaOXA-58-Like Genes

    PubMed Central

    Yang, Qiu; Rui, Yongyu

    2016-01-01

    Nosocomial infections caused by Acinetobacter spp. resistant to carbapenems are increasingly reported worldwide. Carbapenem-resistant Acinetobacter (CRA) is becoming a serious concern with increasing patient morbidity, mortality, and lengths of hospital stay. Therefore, the rapid detection of CRA is essential for epidemiological surveillance. Polymerase chain reaction (PCR) has been extensively used for the rapid identification of most pathogens. In this study, we have developed two multiplex real-time PCR assays to detect and differentiate A. baumannii and non-A. baumannii Acinetobacter spp, and common carbapenemase genes, including blaNDM, blaOXA-23-like, blaOXA-40-like, blaOXA-51-like, and blaOXA-58-like. We demonstrate the potential utility of these assays for the direct detection of blaNDM-, blaOXA-23-like-, blaOXA-40-like-, blaOXA-51-like-, and blaOXA-58-like-positive CRA in clinical specimens. Primers were specifically designed, and two multiplex real-time PCR assays were developed: multiplex real-time PCR assay1 for the detection of Acinetobacter baumannii 16S–23S rRNA internal transcribed spacer sequence, the Acinetobacter recA gene, and class-B-metalloenzyme-encoding gene blaNDM; and multiplex real-time PCR assay2 to detect class-D-oxacillinase-encoding genes (blaOXA-23-like, blaOXA-40-like, blaOXA-51-like,and blaOXA-58-like). The assays were performed on an ABI Prism 7500 FAST Real-Time PCR System. CRA isolates were used to compare the assays with conventional PCR and sequencing. Known amounts of CRA cells were added to sputum and fecal specimens and used to test the multiplex real-time PCR assays. The results for target and nontarget amplification showed that the multiplex real-time PCR assays were specific, the limit of detection for each target was 10 copies per 20 μL reaction volume, the assays were linear over six log dilutions of the target genes (r2 > 0.99), and the Ct values of the coefficients of variation for intra- and interassay

  10. Intraspecies Transfer of the Chromosomal Acinetobacter baumannii blaNDM-1 Carbapenemase Gene.

    PubMed

    Krahn, Thomas; Wibberg, Daniel; Maus, Irena; Winkler, Anika; Bontron, Séverine; Sczyrba, Alexander; Nordmann, Patrice; Pühler, Alfred; Poirel, Laurent; Schlüter, Andreas

    2016-05-01

    The species Acinetobacter baumannii is one of the most important multidrug-resistant human pathogens. To determine its virulence and antibiotic resistance determinants, the genome of the nosocomial blaNDM-1-positive A. baumannii strain R2090 originating from Egypt was completely sequenced. Genome analysis revealed that strain R2090 is highly related to the community-acquired Australian A. baumannii strain D1279779. The two strains belong to sequence type 267 (ST267). Isolate R2090 harbored the chromosomally integrated transposon Tn125 carrying the carbapenemase gene blaNDM-1 that is not present in the D1279779 genome. To test the transferability of the metallo-β-lactamase (MBL) gene region, the clinical isolate R2090 was mated with the susceptible A. baumannii recipient CIP 70.10, and the carbapenem-resistant derivative R2091 was obtained. Genome sequencing of the R2091 derivative revealed that it had received an approximately 66-kb region comprising the transposon Tn125 embedding the blaNDM-1 gene. This region had integrated into the chromosome of the recipient strain CIP 70.10. From the four known mechanisms for horizontal gene transfer (conjugation, outer membrane vesicle-mediated transfer, transformation, and transduction), conjugation could be ruled out, since strain R2090 lacks any plasmid, and a type IV secretion system is not encoded in its chromosome. However, strain R2090 possesses three putative prophages, two of which were predicted to be complete and therefore functional. Accordingly, it was supposed that the transfer of the resistance gene region from the clinical isolate R2090 to the recipient occurred by general transduction facilitated by one of the prophages present in the R2090 genome. Hence, phage-mediated transduction has to be taken into account for the dissemination of antibiotic resistance genes within the species A. baumannii. PMID:26953198

  11. Origins.

    ERIC Educational Resources Information Center

    Online-Offline, 1999

    1999-01-01

    Provides an annotated list of resources dealing with the theme of origins of life, the universe, and traditions. Includes Web sites, videos, books, audio materials, and magazines with appropriate grade levels and/or subject disciplines indicated; professional resources; and learning activities. (LRW)

  12. Detection of blaIMP4 and blaNDM1 harboring Klebsiella pneumoniae isolates in a university hospital in Malaysia

    PubMed Central

    Hamzan, Nurul Izzati; Yean, Chan Yean; Rahman, Rosliza Abdul; Hasan, Habsah; Rahman, Zaidah Abdul

    2015-01-01

    Background Antibiotic resistance among Enterobacteriaceae posts a great challenge to the health care service. The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) is attracting significant attention due to its rapid and global dissemination. The infection is associated with significant morbidity and mortality, thus creating challenges for infection control and managing teams to curb the infection. In Southeast Asia, there have been limited reports and subsequent research regarding CRKP infections. Thus, the study was conducted to characterize CRKP that has been isolated in our setting. Methods A total of 321 K. pneumoniae were included in the study. Each isolate went through an identification process using an automated identification system. Phenotypic characterization was determined using disk diffusion, modified Hodge test, Epsilometer test, and inhibitor combined disk test. Further detection of carbapenemase genes was carried out using polymerase chain reaction and confirmed by gene sequence analysis. Results All together, 13 isolates (4.05%) were CRKP and the majority of them were resistant to tested antibiotics except colistin and tigercycline. Among seven different carbapenemase genes studied (bla KPC, bla IMP, bla SME, bla NDM, bla IMI, bla VIM, and bla OXA), only two, bla IMP4 (1.87%) and bla NDM1 (2.18%), were detected in our setting. Conclusion Evidence suggests that the prevalence of CRKP in our setting is low, and knowledge of Carbapenem-resistant Enterobacteriaceae and CRKP has improved and become available among clinicians. PMID:25765342

  13. Co-Carriage of blaKPC-2 and blaNDM-1 in Clinical Isolates of Pseudomonas aeruginosa Associated with Hospital Infections from India

    PubMed Central

    Paul, Deepjyoti; Dhar Chanda, Debadatta; Maurya, Anand Prakash; Mishra, Shweta; Chakravarty, Atanu; Sharma, Gauri Dutt; Bhattacharjee, Amitabha

    2015-01-01

    Global spread of KPC poses to be a serious threat complicating treatment options in hospital settings. The present study investigates the genetic environment of blaKPC-2 among clinical isolates of Pseudomonas aeruginosa from a tertiary referral hospital of India. The study isolates were collected from different wards and clinics of Silchar Medical College and Hospital, India, from 2012–2013. The presence of blaKPC was confirmed by genotypic characterization followed by sequencing. Cloning of the blaKPC-2 gene was performed and the genetic environment of this gene was characterized as well. Transferability of the resistance gene was determined by transformation assay and Southern hybridization. Additionally, restriction mapping was also carried out. Two isolates of P. aeruginosa were found to harbor blaKPC-2, were resistant towards aminoglycosides, quinolone and β-lactam-β-lactamase inhibitor combination. In both the isolates, the resistance determinant was associated with class 1 integron and horizontally transferable. Both the isolates were co-harboring blaNDM-1. The first detection of this integron mediated blaKPC-2 coexisting with blaNDM-1 in P. aeruginosa from India is worrisome, and further investigation is required to track the gene cassette mediated blaKPC-2 in terms of infection control and to prevent the spread of this gene in hospitals as well as in the community. PMID:26714034

  14. Within-Host and Population Transmission of blaOXA-48 in K. pneumoniae and E. coli

    PubMed Central

    Ossewaarde, Tjaco J. M.; van der Zee, Anneke; den Hollander, Jan G.; Troelstra, Annet; Bonten, Marc J. M.; Bootsma, Martin C. J.

    2015-01-01

    During a large hospital outbreak of OXA-48 producing bacteria, most K. pneumoniaeOXA-48 isolates were phenotypically resistant to meropenem or imipenem, whereas most E. coliOXA-48 isolates were phenotypically susceptible to these antibiotics. In the absence of molecular gene-detection E. coliOXA-48 could remain undetected, facilitating cross-transmission and horizontal gene transfer of blaOXA-48. Based on 868 longitudinal molecular microbiological screening results from patients carrying K. pneumoniaeOXA-48 (n = 24), E. coliOXA-48 (n = 17), or both (n = 40) and mathematical modelling we determined mean durations of colonisation (278 and 225 days for K. pneumoniaeOXA-48 and E. coliOXA-48, respectively), and horizontal gene transfer rates (0.0091/day from K. pneumoniae to E. coli and 0.0015/day vice versa). Based on these findings the maximum effect of horizontal gene transfer of blaOXA-48 originating from E. coliOXA-48 on the basic reproduction number (R0) is 1.9%, and it is, therefore, unlikely that phenotypically susceptible E. coliOXA-48 will contribute significantly to the spread of blaOXA-48. PMID:26485437

  15. Genetic properties of blaCTX-M and blaPER β-lactamase genes in clinical isolates of Enterobacteriaceae by polymerase chain reaction

    PubMed Central

    Moghaddam, Mahboobeh Nakhaei; Beidokhti, Mehrdad Hashemi; Jamehdar, Saeid Amel; Ghahraman, Martha

    2014-01-01

    Objective(s): blaCTX-M and blaPER are two genes that encode class A extended-spectrum β-lactamases (ESBLs) and can be responsible for therapeutic problems. This study was carried out to evaluate the molecular properties of these genes in clinical isolates of Enterobacteriaceae by polymerase chain reaction (PCR), restriction digestion and sequencing. Materials and Methods: During six months, starting from January 2012, one hundred clinical isolates of Enterobacteriaceae were collected from urinary samples. The ESBL-producing isolates were detected by phenotypic confirmation test. After plasmid extraction, blaPER and blaCTX-M genes were detected using PCR by specific primers. The blaCTX-M PCR products were digested with Taq1, and two of the blaCTX-M genes were sequenced. Results: Phenotypic tests showed that 27 (27%) isolates were ESBL producers with the highest frequency for Klebsiella pneumoniae (47.4%) and Escherichia coli (17.9%). Twenty six (26%) of Enterobacteriaceae isolates harbored the blaCTX-M gene, and none of them had blaPER. The restriction analysis of PCR products showed that all blaCTX-M amplified products had the same patterns. Both sequenced bacteria were CTX-M-15 type ESBL carriers. Conclusion: The results of this study showed the blaCTX-M-15 gene in Enterobacteriaceae isolates for the first time in Mashhad, Iran. High degrees of associated resistance to co-trimoxazole and gentamicin were found in ESBL producers. Therefore, an integrated and regular management of antibiotic prescription need to be trained in our society. PMID:24967067

  16. Spread of Enterobacter cloacae carrying blaNDM-1, blaCTX-M-15, blaSHV-12 and plasmid-mediated quinolone resistance genes in a surgical intensive care unit in Croatia.

    PubMed

    Petrosillo, N; Vranić-Ladavac, M; Feudi, C; Villa, L; Fortini, D; Barišić, N; Bedenić, B; Ladavac, R; D'Arezzo, S; Andrašević, A Tambić; Capone, A

    2016-03-01

    The objective of this study was to describe a hospital cluster of NDM-1-producing Enterobacter cloacae infections observed in the surgical intensive care unit (ICU) of a tertiary-care hospital at Pula, Croatia. NDM-1-producing E. cloacae strains isolated from clinical samples were screened by PCR for the presence of carbapenemases. Genetic relatedness of NDM-1-producing E. cloacae strains was determined by multilocus sequence typing (MLST). During the period October 2013 to April 2014, four patients, with overlapping hospital stay in the surgical ICU, developed severe infections caused by E. cloacae demonstrated to produce carbapenemases. According to MLST, all strains belonged to ST133 and were positive by PCR for the blaNDM-1 carbapenemase gene, for blaCTX-M-15 and blaSHV-12 extended-spectrum β-lactamase (ESBL) genes, and for blaTEM-1 and blaOXA-1 narrow-spectrum β-lactamase genes. They were negative for other carbapenemases genes including blaOXA-48, blaVIM and blaKPC as well as for AmpC and the armA and rmtB aminoglycoside resistance genes. All strains were positive for the HI2 replicon, suggesting that an IncHI2 plasmid is likely the plasmid carrying the blaNDM-1 gene. Infection control measures were implemented after the first case although they were not effective in avoiding spread of this organism to other patients in the surgical ICU. In conclusion, the evolving epidemiology of NDM-producing micro-organisms and the interspecies diffusion of this resistance mechanism to emerging pathogens such as E. cloacae necessitate the setting up of strong and urgent joint measures to control the spread of NDM carbapenemase especially in the ICU setting. PMID:27436392

  17. Predominance of carbapenem-resistant Pseudomonas aeruginosa isolates carrying blaIMP and blaVIM metallo-β-lactamases in a major hospital in Costa Rica.

    PubMed

    Toval, Francisco; Guzmán-Marte, Anel; Madriz, Vivian; Somogyi, Teresita; Rodríguez, César; García, Fernando

    2015-01-01

    This study aimed to assess the molecular basis of the resistance to carbapenems in clinical isolates of Pseudomonas aeruginosa recovered from a tertiary-level health facility in San José, Costa Rica. A total of 198 non-duplicated isolates were evaluated for their susceptibility to β-lactams, aminoglycosides and fluoroquinolones. The production of metallo-β-lactamases (MBLs), the presence of MBL encoding genes (blaIMP, blaVIM and blaGIM-1) and the occurrence of these genes within class 1 integrons were investigated. In addition, an ERIC2 PCR fingerprinting method was used to elucidate the distribution of the detected MBL genes within the strain collection. Of the 198 isolates tested, 125 (63.1 %) were categorized as carbapenem-resistant. The majority (88.8 %) of the carbapemen-resistant isolates also showed resistance to ceftazidime, cefepime, aztreonam, ticarcillin/clavulanic acid, amikacin, gentamicin, tobramycin, ciprofloxacin and gatifloxacin. Among the carbapenem-resistant isolates, 102 (81.6 %) showed MBL activity. Strikingly, both blaIMP and blaVIM genes were simultaneously detected in most (94.1 %) of the 102 MBL producers. Five carbapenem-resistant MBL producers were positive only for blaIMP genes. Almost 70 % of the isolates examined harboured the intI1 gene, accompanied by the sul1 and qacEΔ1 genes in 136 (99 %) and 122 (89 %) isolates, respectively. The majority (94.4 %) of the carbapenem-resistant isolates carried the intI1 gene, in contrast to 26 % of the carbapenem-susceptible isolates. Ninety-three out of 96 (96.9 %) isolates carrying both blaIMP and blaVIM genes also harboured the intI1, sul1 and qacEΔ1 genes. Gene cassettes from carbapenem-susceptible and MBL-negative carbapenem-resistant isolates encoded aminoglycoside-resistance enzymes (aadA2, aadA4 and aadA6) as well as orfD and qacF genes. RAPD analysis distributed 126 of the isolates in 29 clusters. Eighty of the 90 blaIMP (+) blaVIM (+) isolates were sorted into 16

  18. Beta-Lactamase Repressor BlaI Modulates Staphylococcus aureus Cathelicidin Antimicrobial Peptide Resistance and Virulence

    PubMed Central

    Pence, Morgan A.; Haste, Nina M.; Meharena, Hiruy S.; Olson, Joshua; Gallo, Richard L.; Nizet, Victor; Kristian, Sascha A.

    2015-01-01

    BlaI is a repressor of BlaZ, the beta-lactamase responsible for penicillin resistance in Staphylococcus aureus. Through screening a transposon library in S. aureus Newman for susceptibility to cathelicidin antimicrobial peptide, we discovered BlaI as a novel cathelicidin resistance factor. Additionally, through integrational mutagenesis in S. aureus Newman and MRSA Sanger 252 strains, we confirmed the role of BlaI in resistance to human and murine cathelidicin and showed that it contributes to virulence in human whole blood and murine infection models. We further demonstrated that BlaI could be a target for innate immune-based antimicrobial therapies; by removing BlaI through subinhibitory concentrations of 6-aminopenicillanic acid, we were able to sensitize S. aureus to LL-37 killing. PMID:26305782

  19. Clinical Performance of Check-Direct CPE, a Multiplex PCR for Direct Detection of bla(KPC), bla(NDM) and/or bla(VIM), and bla(OXA)-48 from Perirectal Swabs.

    PubMed

    Lau, Anna F; Fahle, Gary A; Kemp, Margaret A; Jassem, Agatha N; Dekker, John P; Frank, Karen M

    2015-12-01

    We evaluated the clinical performance of Check-Direct CPE for carbapenemase detection directly from 301 perirectal swabs (258 patients) in a nonoutbreak setting. Culture of a PCR-confirmed, carbapenemase-containing organism, or history of colonization with such organism within the previous 2 weeks, was used as the reference standard. Check-Direct CPE demonstrated a sensitivity value, specificity value, positive predictive value (PPV), and negative predictive value (NPV) of 100% (all bla(KPC)), 88%, 21%, and 100%, respectively. False positives accounted for 79% (n = 34) of samples for which a cycle threshold (C(T)) value was reached. Simulated studies to evaluate specimen pooling as an approach to minimize costs showed no difference in C(T) values for pooled groups of three or five that each contained a single specimen spiked with ∼1,500 CFU bla(KPC) Klebsiella pneumoniae; however, the detection rate dropped to 60% at a seeded concentration of ∼150 CFU. When data were pooled, C(T) values for bla(KPC) were higher for heavy-feces-containing than for light-feces-containing liquid-suspended specimens. Furthermore, C(T) values for liquid-suspended specimens were 4 to 5 C(T) values lower (i.e., represented greater sensitivity) than those seen in direct swab analysis. Culture was equivalent to or better than Check-Direct CPE for 13/15 (87%) isolates tested in a limit-of-detection analysis. Detection of a carbapenemase gene at a C(T) cutoff value of ≤35 was culture confirmed in 23/24 (96%) of cases; however, C(T) values of >35 overlapped broadly between culture-positive (n = 21) and culture-negative (n = 36) specimens. Check-Direct CPE will likely prove most useful in high-prevalence areas or in outbreak settings where rapid carbapenemase detection is critical for infection control management. PMID:26338860

  20. Complete Nucleotide Sequence of a Conjugative Plasmid Carrying blaPER-1

    PubMed Central

    Li, Ruichao; Zhou, Yuanjie; Chan, Edward Wai-chi

    2015-01-01

    The nucleotide sequence of a self-transmissible plasmid pVPH1 harboring blaPER-1 from Vibrio parahaemolyticus was determined. pVPH1 was 183,730 bp in size and shared a backbone similar to pAQU1 and pAQU2, differing mainly in an ∼40-kb multidrug resistance (MDR) region. A complex class 1 integron was identified together with ISCR1 and blaPER-1 (ISCR1-blaPER-1-gst-abct-qacEΔ1-sul1), which was shown to form a circular intermediate playing an important role in the dissemination of blaPER-1. PMID:25779581

  1. Molecular dissection of blaKPC-2-bearing plasmids evolving in Klebsiella pneumoniae isolated at one teaching hospital in Shanghai, China.

    PubMed

    Shen, Pinghua; Zhang, Ying; Tang, Yu; Liang, Wei; Jiang, Xiaofei

    2016-08-01

    The presence of carbapenemase gene blaKPC-2 in a wide variety of plasmids, especially conjugative plasmids, is key to the rapid, worldwide spread of carbapenemase enzymes. Thirty-eight, non-duplicated, carbapenem-resistant, clinical Klebsiella pneumoniae isolates were collected, all carrying blaKPC-2-bearing plasmids. Relaxase analysis was used to classify these plasmids; 8 and 30 plasmids belonged to the MOBP3 and MOBF12 subfamilies, respectively. Phylogenetic analysis revealed two genetic subclades in the MOBF12 subfamily and suggested that these subclades might not have originated from the same ancestor. Crossing PCR, used to sequence fully the type IV secretion system (T4SS, essential structures for conjugative plasmids) of the MOBF12 plasmids, found that T4SSs were distinctively different in certain functional genes, e.g. traS and traG. In conclusion, this study delineated the evolution of blaKPC-2-bearing plasmids at Huashan Hospital, Shanghai, China. The plasmids bearing blaKPC-2 were diverse and the MOBF12 plasmids were dominant in clinical K. pneumoniae isolates. PMID:27252157

  2. Pathotyping blaCTX-M Escherichia coli from Nigeria

    PubMed Central

    Olowe, Olugbenga Adekunle; Choudhary, Suman; Schierack, Peter; Wieler, Lothar H.; Olayemi, Albert B.; Anjum, Muna

    2013-01-01

    Background: Escherichia coli have become the enterobacteriaceae species most affected by extended-spectrum β-lactamases (ESBLs) in view of the emergence of CTX-M-type ESBLs. These CTX-M-positive E. coli have been reported in numerous regions worldwide. Virulence determinants of already reported CTX-M-positive E. coli were investigated. Methodology: To gain insights into the mechanism underlying this phenomenon, we assessed serogroup, susceptibility pattern and diversity of virulence profiles within a collection of nine blaCTX-M-positive E. coli strains and their virulent determinant using miniaturized DNA microarray techniques. The nine ESBL-positive E. coli isolates were from eight male and one female patient(s) selected for study based on previous work. Virulence potential was inferred by detection of 63 virulence factor (VF) genes. Results: Four (44.4%) of the 9 E. coli isolates exhibited the same set of core characteristics: serotype O8:Hnt, while all were positive for OXA-1, ciprofloxacin resistance. Five of the isolates exhibited highly similar (91% to 100%) VF profiles. Conclusion: The findings describe a broadly disseminated, blaCTX-M-positive and virulent E. coli serogroup with highly homogeneous virulence genotypes, suggesting recent emergence in this zone. Understanding how this clone has emerged and successfully disseminated within the hospital and community, including across national boundaries, should be a public health priority. PMID:24265928

  3. Klebsiella pneumoniae Isolate from a New York City Hospital Belonging to Sequence Type 258 and Carrying blaKPC-2 and blaVIM-4

    PubMed Central

    Deshpande, Lalitagauri M.; Mills, Janet C.; Jones, Ronald N.; Soave, Rosemary; Jenkins, Stephen G.; Schuetz, Audrey N.

    2016-01-01

    Among 69 of 139 (49.6%) carbapenem-nonsusceptible Enterobacteriaceae carrying blaKPC, 1 Klebsiella pneumoniae was also positive for blaVIM. The isolate belonged to sequence type 258 (ST258) and carried blaKPC-2 on a copy of Tn4401a and blaVIM-4 on a class 1 integron. Genes were located on distinct plasmids belonging to Inc types A/C and FII. Elevated expression of the efflux pump AcrAB-TolC (acrA, 15.3 times) and reduced expression of outer membrane protein genes ompK35 and ompK37 (0.16 and 0.081 times, respectively) associated with various amino acid alterations on OmpK37 were observed. The presence of two carbapenemases in ST258 K. pneumoniae is of great concern due to the ability of this organism to widely disseminate. PMID:26729504

  4. The establishment of a duplex real-time PCR assay for rapid and simultaneous detection of blaNDM and blaKPC genes in bacteria

    PubMed Central

    2013-01-01

    The latest threat of multidrug-resistant Gram-negative bacteria corresponds to the emergence of carbapenemase New Delhi metallo-β-lactamase (NDM) and Klebsiella pneumoniae carbapenemase (KPC) producers. Rapid molecular detection is essential to limit their spread. In this study, a duplex real-time polymerase chain reaction (PCR) that was specific for the detection of blaNDM and blaKPC with the same limit of detection of ten plasmid copies was developed. The assay was linear over eight log dilutions for blaNDM (R2 = 0.971; slope, -3.273) and blaKPC (R2 = 0.992; slope, -2.997) with efficiencies of 102% and 115%, respectively. The assay was validated with 157 clinical isolates and showed 100% concordance with conventional PCR. The excellent performance of the duplex PCR assay makes it a powerful tool for surveillance of the carbapenemases NDM and KPC. PMID:24143953

  5. [Distribution of blaOXA genes in Acinetobacter baumannii strains: a multicenter study].

    PubMed

    Ciftci, Ihsan Hakkı; Aşık, Gülşah; Karakeçe, Engin; Oksüz, Lütfiye; Yağcı, Server; Sesli Çetin, Emel; Ozdemir, Mehmet; Atasoy, Ali Rıza; Koçoğlu, Esra; Gül, Mustafa; Kurtoğlu, Muhammet Güzel; Köksal Çakırlar, Fatma; Seyrek, Adnan; Berktaş, Mustafa; Gültepe, Bilge; Ayyildiz, Ahmet

    2013-10-01

    Acinetobacter baumannii is the most important agent of nosocomial infections within the Acinetobacter genus. This gram-negative coccobacillus is intrinsically resistant to many antibiotics used in antimicrobial therapy, and capable of developing resistance including carbapenems. The objective of this study was to develop a multiplex real time polymerase chain reaction (qPCR) kit for OXA subgroups in A.baumannii, and to investigate the distribution of OXA subgroups in A.baumannii strains isolated from geographically different regions of Turkey. A total of 834 A.baumannii clinical isolates collected from different state and university medical centers in 13 provinces (Afyonkarahisar, Ankara, Bolu, Elazig, Erzurum, Isparta, Istanbul, Kahramanmaras, Konya, Sakarya, Van) between 2008-2011, were included in the study. The isolates were identified by conventional methods and automated systems [Vitek2 (bioMerieux, ABD) and Phoenix (BD Diagnostic, MD)]. The susceptibility profiles of the isolates were studied with automated systems and standard disc diffusion method. All samples were subjected to qPCR to detect blaOXA-51-like, blaOXA-23-like and blaOXA-58-like genes. A conventional PCR method was also used to detect blaOXA-24-like gene. The resistance rates observed during the study period were as follows: 96.8% for amoxicillin-clavulanate, 86.8% for ciprofloxacin, 74.7% for gentamicin, 71.7% for amikacin, 73.5% for cefaperozone-sulbactam, 72.1% for imipenem and 73% for meropenem. Six hundred and two (72.2 %) isolates were resistant to both imipenem and meropenem. Colistin was found to be the most effective antibiotic against A.baumannii isolates with 100% susceptibility rate. All isolates were positive for blaOXA-51-like, however blaOXA-24-like gene could not be demonstrated in any isolate. Total positivity rates of blaOXA-23-like and blaOXA-58-like genes were found as 53.7% and 12.5%, respectively, while these rates were 74.4% and 17.3% in carbapenem-resistant isolates

  6. Prevalence of extended-spectrum cephalosporin-resistant Escherichia coli in a farrowing farm: ST1121 clone harboring IncHI2 plasmid contributes to the dissemination of blaCMY-2

    PubMed Central

    Deng, Hui; Si, Hong-Bin; Zeng, Shu-Yi; Sun, Jian; Fang, Liang-Xing; Yang, Run-Shi; Liu, Ya-Hong; Liao, Xiao-Ping

    2015-01-01

    During a regular monitoring of antimicrobial resistance in a farrowing farm in Southern China, 117 Escherichia coli isolates were obtained from sows and piglets. Compared with the isolates from piglets, the isolates from sows exhibited higher resistance rates to the tested cephalosporins. Correspondingly, the total detection rate of the blaCMY-2/blaCTX-M genes in the sow isolates (34.2%) was also significantly higher than that of the piglet isolates (13.6%; p < 0.05). The blaCMY-2 gene had a relatively high prevalence (11.1%) in the E. coli isolates. MLST and PFGE analysis revealed the clonal spread of ST1121 E. coli in most (7/13) of the blaCMY-2-positive isolates. An indistinguishable IncHI2 plasmid harboring blaCMY-2 was also identified in each of the seven ST1121 E. coli isolates. Complete sequence analysis of this IncHI2 plasmid (pEC5207) revealed that pEC5207 may have originated through recombination of an IncHI2 plasmid with a blaCMY-2-carrying IncA/C plasmid like pCFSAN007427_01. In addition to blaCMY-2, pEC5207 also carried other resistance determinants for aminoglycosides (aacA7), sulfonamides (sul1), as well as heavy metals ions, such as Cu and Ag. The susceptibility testing showed that the pEC5207 can mediate both antibiotic and heavy metal resistance. This highlights the role of pEC5207 in co-selection of blaCMY-2-positive isolates under the selective pressure of heavy metals, cephalosporins, and other antimicrobials. In conclusion, clonal spread of an ST1121 type E. coli strain harboring an IncHI2 plasmid contributed to the dissemination of blaCMY-2 in a farrowing farm in Southern China. We also have determined the first complete sequence analysis of a blaCMY-2-carrying IncHI2 plasmid. PMID:26579110

  7. BLA to vHPC Inputs Modulate Anxiety-Related Behaviors

    PubMed Central

    Felix-Ortiz, Ada C.; Beyeler, Anna; Seo, Changwoo; Leppla, Christopher A.; Wildes, Craig P.; Tye, Kay M.

    2014-01-01

    SUMMARY The basolateral amygdala (BLA) and ventral hippocampus (vHPC) have both been implicated in mediating anxiety-related behaviors, but the functional contribution of BLA inputs to the vHPC has never been directly investigated. Here we show that activation of BLA-vHPC synapses acutely and robustly increased anxiety-related behaviors, while inhibition of BLA-vHPC synapses decreased anxiety-related behaviors. We combined optogenetic approaches with in vivo pharmacological manipulations and ex vivo whole-cell patch-clamp recordings to dissect the local circuit mechanisms, demonstrating that activation of BLA terminals in the vHPC provided monosynaptic, glutamatergic inputs to vHPC pyramidal neurons. Furthermore, BLA inputs exerted polysynaptic, inhibitory effects mediated by local interneurons in the vHPC that may serve to balance the circuit locally. These data establish a role for BLA-vHPC synapses in bidirectionally controlling anxiety-related behaviors in an immediate, yet reversible, manner and a model for the local circuit mechanism of BLA inputs in the vHPC. PMID:23972595

  8. BLA to vHPC inputs modulate anxiety-related behaviors.

    PubMed

    Felix-Ortiz, Ada C; Beyeler, Anna; Seo, Changwoo; Leppla, Christopher A; Wildes, Craig P; Tye, Kay M

    2013-08-21

    The basolateral amygdala (BLA) and ventral hippocampus (vHPC) have both been implicated in mediating anxiety-related behaviors, but the functional contribution of BLA inputs to the vHPC has never been directly investigated. Here we show that activation of BLA-vHPC synapses acutely and robustly increased anxiety-related behaviors, while inhibition of BLA-vHPC synapses decreased anxiety-related behaviors. We combined optogenetic approaches with in vivo pharmacological manipulations and ex vivo whole-cell patch-clamp recordings to dissect the local circuit mechanisms, demonstrating that activation of BLA terminals in the vHPC provided monosynaptic, glutamatergic inputs to vHPC pyramidal neurons. Furthermore, BLA inputs exerted polysynaptic, inhibitory effects mediated by local interneurons in the vHPC that may serve to balance the circuit locally. These data establish a role for BLA-vHPC synapses in bidirectionally controlling anxiety-related behaviors in an immediate, yet reversible, manner and a model for the local circuit mechanism of BLA inputs in the vHPC. PMID:23972595

  9. The major cockroach allergen Bla g 4 binds tyramine and octopamine.

    PubMed

    Offermann, Lesa R; Chan, Siew Leong; Osinski, Tomasz; Tan, Yih Wan; Chew, Fook Tim; Sivaraman, J; Mok, Yu-Keung; Minor, Wladek; Chruszcz, Maksymilian

    2014-07-01

    Bla g 4 is a male cockroach specific protein and is one of the major allergens produced by Blattella germanica (German cockroach). This protein belongs to the lipocalin family that comprises a set of proteins that characteristically bind small hydrophobic molecules and play a role in a number of processes such as: retinoid and pheromone transport, prostaglandin synthesis and mammalian immune response. Using NMR and isothermal titration calorimetry we demonstrated that Bla g 4 binds tyramine and octopamine in solution. In addition, crystal structure analysis of the complex revealed details of tyramine binding. As tyramine and octopamine play important roles in invertebrates, and are counterparts to vertebrate adrenergic transmitters, we speculate that these molecules are physiological ligands for Bla g 4. The nature of binding these ligands to Bla g 4 sheds light on the possible biological function of the protein. In addition, we performed a large-scale analysis of Bla g 4 and Per a 4 (an allergen from American cockroach) homologs to get insights into the function of these proteins. This analysis together with a structural comparison of Blag 4 and Per a 4 suggests that these proteins may play different roles and most likely bind different ligands. Accession numbers: The atomic coordinates and the structure factors have been deposited to the Protein Data Band under accession codes: 4N7C for native Bla g 4 and 4N7D for the Se-Met Bla g 4 structure. PMID:24769496

  10. Complete Sequence of a blaKPC-Harboring Cointegrate Plasmid Isolated from Escherichia coli

    PubMed Central

    Chavda, Kalyan D.; Chen, Liang; Jacobs, Michael R.; Rojtman, Albert D.; Bonomo, Robert A.

    2015-01-01

    Horizontal transfer of blaKPC-harboring plasmids contributes significantly to the inter- and intraspecies spread of Klebsiella pneumoniae carbapenemase (KPC). Here we report the complete nucleotide sequence of a blaKPC-harboring IncFIA plasmid, pBK32533, from Escherichia coli. pBK32533 is a cointegrate plasmid comprising of a 72-kb sequence identical to that of the nonconjugative pBK30661 plasmid plus an additional 170-kb element that harbors the genes for plasmid transfer. pBK32533 demonstrates how blaKPC can be spread from a nonconjugative plasmid through cointegration. PMID:25753632

  11. Tn125-Related Acquisition of blaNDM-Like Genes in Acinetobacter baumannii

    PubMed Central

    Poirel, Laurent; Bonnin, Rémy A.; Boulanger, Anne; Schrenzel, Jacques; Kaase, Martin

    2012-01-01

    A multidrug-resistant Acinetobacter baumannii isolate recovered from a patient hospitalized in Switzerland after a transfer from Serbia produced the NDM-1 carbapenemase. The blaNDM-1 gene was part of a chromosomally located Tn125 composite transposon bracketed by two copies of the same insertion sequence, ISAba125. This transposon was also associated with the acquisition and expression of the blaNDM-2 gene in an A. baumannii isolate in Germany. Tn125 appears to be the main vehicle for dissemination of blaNDM genes in that species. PMID:22143526

  12. Molecular characterization of newly emerged blaKPC-2-producing Klebsiella pneumoniae in Singapore.

    PubMed

    Balm, Michelle N D; Ngan, Grace; Jureen, Roland; Lin, Raymond T P; Teo, Jeanette

    2012-02-01

    In Asia, bla(KPC) detection has been limited to East Asia and not yet seen in Southeast Asia. We report four bla(KPC-2)-containing Klebsiella pneumoniae isolates from two different hospitals in Singapore. All isolates belonged to strain type 11 (ST11) and were indistinguishable by pulsed-field gel electrophoresis (PFGE). bla(KPC-2) was located on nonconjugative plasmids and flanked by mobile genetic structures composed of a partial Tn4401 transposon and a Tn3-based transposon which previously have been described only in Chinese isolates. PMID:22116160

  13. IncI1 plasmids associated with the spread of CMY-2, CTX-M-1 and SHV-12 in Escherichia coli of animal and human origin.

    PubMed

    Accogli, M; Fortini, D; Giufrè, M; Graziani, C; Dolejska, M; Carattoli, A; Cerquetti, M

    2013-05-01

    Fourteen plasmids carrying blaCTX -M-1, blaSHV -12 or blaCMY -2 genes from Escherichia coli of both avian and human origin were analysed. IncI1 plasmids were largely predominant. Plasmid mutilocus sequence typing and comparative analysis revealed that the blaCMY -2 -ST12-IncI1 plasmids from avian E. coli were identical to those previously found in Salmonella from humans, but different to those associated with human E. coli. The IncI1-ST3 plasmids carrying blaCTX -M-1 or blaSHV -12 were related to those previously identified in avian E. coli, but different to those identified in human E. coli. Overall, no plasmids shared by E. coli of both origin (human/avian) were identified; however, further investigations are needed. PMID:23331857

  14. Occurrence and characteristics of extended spectrum beta-lactamases-producing Enterobacteriaceae from foods of animal origin.

    PubMed

    Tekiner, İsmail Hakkı; Özpınar, Haydar

    2016-01-01

    Presence of extended spectrum beta-lactamases (ESBL) in bacteria is a growing health concern of global significance. The local, regional, national, and international epidemiological studies for extended spectrum beta-lactamases-producing Enterobacteriaceae and their encoding genes in foods are still incomplete. The objective of this study was to determine the occurrence of extended spectrum beta-lactamases-producing Enterobacteriaceae and the characteristics of their encoding genes from a total of 250 samples of various foods of animal-origin (100 raw chicken meat, 100 raw cow milk, and 50 raw cow milk cheese) sold in Turkey. Overall, 55 isolates were positive as extended spectrum beta-lactamases-producing Enterobacteriaceae. The most prevalent extended spectrum beta-lactamases-producing strain were identified as Escherichia coli (80%), followed by Enterobacter cloacae (9.1%), Citrobacter braakii (5.5%), Klebsiella pneumoniae (3.6%), and Citrobacter werkmanii (1.8%) by Vitek(®) MS. The simultaneous production of extended spectrum beta-lactamases and AmpC was detected in five isolates (9.1%) in E. coli (80%) and E. cloacae (20%). The frequency rates of blaTEM, blaCTX-M, and blaSHV were 96.4%, 53.7%, and 34.5%, respectively. The co-existence of bla-genes was observed in 82% of extended spectrum beta-lactamases producers with a distribution of blaTEM &blaCTX-M (52.7%), blaTEM &blaSHV (20%), blaTEM &blaCTX-M &blaSHV (12.7%), and blaSHV &blaCTX-M (1.8%). The most prevalent variant of blaCTX-M clusters was defined as blaCTX-M-1 (97.2%), followed by blaCTX-M-8 (2.8%). In summary, the analysed foods were found to be posing a health risk for Turkish consumers due to contamination by Enterobacteriaceae with a diversity of extended spectrum beta-lactamases encoding genes. PMID:26991276

  15. Chromosomal beta-lactamase genes of Klebsiella oxytoca are divided into two main groups, blaOXY-1 and blaOXY-2.

    PubMed Central

    Fournier, B; Roy, P H; Lagrange, P H; Philippon, A

    1996-01-01

    The chromosomally encoded beta-lactamase gene (blaOXY-2) of the wild-type Klebsiella oxytoca SL911 was cloned and sequenced. Its nucleotide sequence similarity with the previously sequenced K. oxytoca beta-lactamase gene (blaOXY-1) (Y. Arakawa, M. Ohta, N. Kido, M. Mori, H. Ito, T. Komatsu, Y. Fujii, and N. Kato, Antimicrob. Agents Chemother. 33:63-70, 1989) is 87.3%, and its amino acid similarity is 89.7%. This group of K. oxytoca beta-lactamases is related to chromosomal beta-lactamases of Citrobacter diversus, Proteus vulgaris, and Yersinia enterocolitica and to the plasmid-mediated extended-spectrum beta-lactamases MEN-1 and Toho-1. By colony hybridization with 86 strains susceptible and resistant to aztreonam, isolated in six countries, K. oxytoca beta-lactamase genes hybridized with either a specific blaOXY-1 DNA probe (668 bp) or a blaOXY-2 DNA probe (723 bp). Thus, beta-lactamase genes could be divided into two groups: blaOXY-1 (47% of the strains) and blaOXY-2 (53% of the strains). A study of isoelectric points confirmed the great variability reported in the literature. However, the two beta-lactamase groups were each represented by four different pIs: for OXY-2, 5.2, 5.7, 6.4, and 6.8, with the 5.2 form representing 59% of all OXY-2 enzymes, and for OXY-1, 7.1, 7.5, 8.2, and 8.8, with the 7.5 form representing 88% of all OXY-1 enzymes. PMID:8834897

  16. Novel variant (bla(VIM-4)) of the metallo-beta-lactamase gene bla(VIM-1) in a clinical strain of Pseudomonas aeruginosa.

    PubMed

    Pournaras, Spyros; Tsakris, Athanassios; Maniati, Maria; Tzouvelekis, Leonidas S; Maniatis, Antonios N

    2002-12-01

    A Pseudomonas aeruginosa isolate highly resistant to carbapenems was collected from a patient with postsurgical cerebrospinal infection in Greece. The isolate carried a class 1 integron that contained as a sole cassette the gene bla(VIM-4), a novel variant of bla(VIM-1), with one nucleotide difference resulting in a Ser-to-Arg change at amino acid position 175 of the VIM-1 enzyme. This is the first detection of a VIM-1 variant after its appearance in Italy. PMID:12435718

  17. IncI1 Plasmids Carrying Various blaCTX-M Genes Contribute to Ceftriaxone Resistance in Salmonella enterica Serovar Enteritidis in China

    PubMed Central

    Kan, Biao; Chan, Edward Wai-chi

    2015-01-01

    Resistance to extended-spectrum β-lactams in Salmonella, in particular, in serotypes such as Salmonella enterica serovar Enteritidis that are frequently associated with clinical infections, is a serious public health concern. In this study, phenotypic characterization of 433 clinical S. Enteritidis strains obtained from a nationwide collection of the Chinese Center for Disease Control and Prevention during the period from 2005 to 2010 depicted a trend of increasing resistance to ceftriaxone from 2008 onwards. Seventeen (4%) of the strains were found to be resistant to ceftriaxone, 7% were found to be resistant to ciprofloxacin, and 0.7% were found to be resistant to both ciprofloxacin and ceftriaxone. Most of the ceftriaxone-resistant S. Enteritidis strains (15/17) were genetically unrelated and originated from Henan Province. The complete sequence of an IncI1 plasmid, pSE115, which belonged to a novel sequence type, was obtained. This 87,255-bp IncI1 plasmid was found to harbor a blaCTX-M-14 gene in a novel multidrug resistance region (MRR) within the tra locus. Although the majority of strains were also found to contain conjugative IncI1 plasmids with a size similar to that of pSE115 (∼90 kb) and harbor a variety of blaCTX-M group 1 and group 9 elements, the novel MRR site at the tra locus in pSE115 was not detectable in the other IncI1 plasmids. The findings from this study show that cephalosporin resistance in S. Enteritidis strains collected in China was mainly due to the dissemination of IncI1 plasmids carrying blaCTX-M, resembling the situation in which IncI1 plasmids serve as major vectors of blaCTX-M variants in other members of the Enterobacteriaceae. PMID:26643327

  18. Chromosomal location of blaCTX-M genes in clinical isolates of Escherichia coli from Germany, The Netherlands and the UK.

    PubMed

    Rodríguez, I; Thomas, K; Van Essen, A; Schink, A-K; Day, M; Chattaway, M; Wu, G; Mevius, D; Helmuth, R; Guerra, B

    2014-06-01

    This study aimed to detect and characterise clinical Escherichia coli isolates suspected of carrying chromosomally encoded CTX-M enzymes. Escherichia coli (n=356) obtained in Germany, The Netherlands and the UK (2005-2009) and resistant to third-generation cephalosporins were analysed for the presence of ESBL-/AmpC-encoding genes within the European SAFEFOODERA-ESBL project. β-Lactamases and their association with IS26 and ISEcp1 were investigated by PCR. Isolates were typed by phylogenetic grouping, MLST and PFGE. Plasmids were visualised by S1 nuclease PFGE, and the location of blaCTX-M genes was determined by Southern hybridisation of XbaI-, S1- and I-CeuI-digested DNA. ESBL enzymes could not be located on plasmids in 17/356 isolates (4.8%). These 17 isolates, from different countries and years, were ascribed to phylogenetic groups D (9), B2 (6) and B1 (2), and to seven sequence types, with ST38 being the most frequent (7 phylogroup D isolates). Eleven isolates produced CTX-M-15. blaCTX-M-15 genes were associated with ISEcp1. The remaining isolates expressed the CTX-M group 9 β-lactamases CTX-M-14 (4), CTX-M-9 (1) and CTX-M-51 (1). blaCTX-M probes hybridised with I-CeuI- and/or XbaI-digested DNA, but not with S1-digested DNA, corroborating their chromosomal location. To summarise, only 4.8% of a large collection of ESBL-producing E. coli isolates harboured chromosomal blaCTX-M genes. These isolates were of human origin and belonged predominantly to ST38 and ST131, which possibly indicates the role of these sequence types in this phenomenon. However, heterogeneity among isolates was found, suggesting that their spread is not only due to the dispersion of successful E. coli clones. PMID:24816185

  19. Beta-Lactamase Encoded Genes blaTEM and blaCTX Among Acinetobacter baumannii Species Isolated From Medical Devices of Intensive Care Units in Tehran Hospitals

    PubMed Central

    Khalilzadegan, Sara; Sade, Mojtaba; Godarzi, Hussein; Eslami, Gita; Hallajzade, Masoumeh; Fallah, Fatemeh; Yadegarnia, Davood

    2016-01-01

    Background Excessive consumption of antimicrobial materials in hospitals is considered as the main encoder leading to the emergence, development and acquisition of new bacterial resistance to beta-lactamase. Objectives Owing to the lack of proper information regarding the mechanism of the bacterial resistance to antibiotics and responsible genes in the country, the current study aimed to consider the resistance or sensitivity of the Acinetobacter baumannii multi drug resistant (MDR) isolates facing 2% glutaraldehyde. The study was conducted in the selected intensive care units in Tehran hospitals, Iran, in 2013. Materials and Methods In this study conducted over a period of 10 months, A. baumannii species were isolated by bacterial culture following biochemical tests from intensive care units (ICUs) of some hospitals in Tehran, Iran (Fayazbaksh, Taleghani, Imam Khomeini, Valiasr, Labafinejad). The resistance and sensitivity of the isolates to antibiotics were considered according to the clinical and laboratory standard institute CLSI (2012) guidelines. By multiplex PCR method, blaCTX and blaTEM genes were detected and finally, MDR strains were treated with 2% glutaraldehyde. PCR was used for each strain of MDR using specific primers. Results In the current study, 131 A. baumannii isolates (22.3%) out of 588 were studied. The level of resistance to various antibiotics was in the range of 69.4% to 100%. The frequencies of blaTEM and blaCTX genes were 3.2% and 19.4%, respectively. MIC50% and MIC90% of imipenem and meropenem antibiotics were 32 ± 1 µg/mL and 64 ± 1 µg/mL, respectively (P < 0.9). However no resistance to glutaraldehyde was observed. Different bands of MDR strains were observed in the PCR product by electrophoresis. Conclusions It seems that besides the variety and prevalence of blaTEM and blaCTX, enormous mechanisms such as porin and leaking systems (efflux pumps) are responsible for the information of the A. baumannii resistance to disinfectants

  20. Highly conjugative IncX4 plasmids carrying blaCTX-M in Escherichia coli from humans and food animals.

    PubMed

    Lo, Wai-U; Chow, Kin-Hung; Law, Pierra Y; Ng, Ka-Ying; Cheung, Yuk-Yam; Lai, Eileen L; Ho, Pak-Leung

    2014-06-01

    This study investigated the prevalence of IncX plasmid subtypes in commensal and pathogenic Escherichia coli isolates and the biological features of the IncX4 subtype. Two hundred and twenty-five E. coli isolates from multiple sources (47 chickens, 41 pigs, 30 cattle and 107 humans) obtained during the period 2006-2012 were tested for the presence of IncX1 to IncX5. Overall, the prevalence of IncX plasmids in chicken, pig, cattle and human isolates were 21.2 % (10/47), 19.5 % (8/41), 3.3 % (1/30) and 4.8 % (5/107), respectively. IncX4 was the most common subtype, followed by IncX1 and IncX3, while no IncX2 or IncX5 were found. Seven out of 16 (43.8 %) IncX4 plasmids were found to carry blaCTX-M genes and six of them originating from different host sources (four chickens, one pig and one human) had identical or highly similar RFLP patterns. Three IncX4 plasmids carrying blaCTX-M from different host sources were investigated further. It was found that the IncX4 plasmids had little effect on bacterial host growth parameters after their introduction to J53 recipients. Conjugation experiments demonstrated that the IncX4 plasmids could be efficiently transferred at 30-42 °C at rates which were generally 10(2)-10(5)-fold higher than those for the epidemic IncFII plasmid carrying blaCTX-M (pHK01). In conclusion, the IncX plasmids are more common than previously recognized. The efficient transfer of IncX4 plasmid at different temperatures and the lack of fitness burden on bacterial hosts highlight the ability of this plasmid replicon to be an important vehicle for dissemination of antimicrobial resistance. PMID:24595536

  1. Characterization of blaTEM-52-carrying plasmids of extended-spectrum-β-lactamase-producing Salmonella enterica isolates from chicken meat with a common supplier in Japan.

    PubMed

    Matsumoto, Yuko; Izumiya, Hidemasa; Sekizuka, Tsuyoshi; Kuroda, Makoto; Ohnishi, Makoto

    2014-12-01

    The acquisition of resistance to cephalosporins among Salmonella spp. is a major public health concern. This study identified clonal plasmids carrying bla(TEM-52) from 10 Salmonella enterica serovar Infantis and Manhattan isolates from retail chicken meats that originated from a common supplier in Japan. Whole-genome analyses of the representative plasmids, including pYM4, revealed that they are 38 kb in size and that pYM4 is identical to pDKX1 from beef in Denmark, suggesting a global dissemination of resistance mediated by the plasmids. PMID:25246394

  2. Initial Assessment of the Molecular Epidemiology of blaNDM-1 in Colombia.

    PubMed

    Rojas, Laura J; Wright, Meredith S; De La Cadena, Elsa; Motoa, Gabriel; Hujer, Kristine M; Villegas, Maria V; Adams, Mark D; Bonomo, Robert A

    2016-07-01

    We report complete genome sequences of four blaNDM-1-harboring Gram-negative multidrug-resistant (MDR) isolates from Colombia. The blaNDM-1 genes were located on 193-kb Inc FIA, 178-kb Inc A/C2, and 47-kb (unknown Inc type) plasmids. Multilocus sequence typing (MLST) revealed that these isolates belong to sequence type 10 (ST10) (Escherichia coli), ST392 (Klebsiella pneumoniae), and ST322 and ST464 (Acinetobacter baumannii and Acinetobacter nosocomialis, respectively). Our analysis identified that the Inc A/C2 plasmid in E. coli contained a novel complex transposon (Tn125 and Tn5393 with three copies of blaNDM-1) and a recombination "hot spot" for the acquisition of new resistance determinants. PMID:27067339

  3. Separation and confirmation of nine Enterobacteriaceae strains that carry the blaNDM-1 gene

    PubMed Central

    LI, TIAN-JIAO; LI, CHEN-XUE; CHENG, SHU-PING; WANG, XU-MING; FU, SHENG-MIAO; LI, XIAO-JUAN; HUANG, TAO; FU, HUI-QUN; LIN, SONG; LU, YE

    2015-01-01

    The aim of the present study was to confirm the existence of carbapenem-resistant Enterobacteriaceae carrying the blaNDM-1 gene in clinics in Hainan province, China. Collected clinical bacterial isolates that were Enterobacteriaceae strains suspected of producing carbapenemase were used as experimental strains. Drug resistance to imipenem, meropenem and other antibacterial agents was tested. Imipenem/imipenem inhibitor (IP/IPI) E-testing was conducted to identify the bacterial strains that produced metallo-β-lactamases. The blaNDM-1 drug resistance gene was amplified by polymerase chain reaction (PCR), and agarose gel electrophoresis (AGE) and sequencing were conducted to identify the products. The species of the strains carrying the blaNDM-1 gene were determined using a biochemical identification system. Through the IP/IPI E-test, 21 of the 30 collected Enterobacteriaceae strains were found to be positive, indicating that 70% of the strains produced metallo-β-lactamases. Following blaNDM-1 gene PCR amplification, AGE and sequencing tests confirmed that nine of the strains carried the blaNDM-1 drug resistance gene. The biochemical identification system indicated that four of the strains were Klebsiella pneumoniae, two were Escherichia coli, two were Enterobacter cloacae and one was Enterobacter aerogenes. Drug susceptibility testing in vitro demonstrated that the strains were 100% resistant to a broad spectrum antibiotic plus lactamase inhibitor, cephalosporins and carbapenems. However, they had high sensitivity rates to polymyxin B and tigecycline of 100 and 88.9%, respectively. The sensitivity rate to amikacin was also high at 77.8%, whereas sensitivity to ciprofloxacin and gentamicin was moderate at rates of 44.4 and 33.3% respectively. This clinical study of Enterobacteriaceae strains that carry the blaNDM-1 gene in Hainan shows a bacterial tolerance that is different from that in previous studies, which requires further in-depth study. PMID:25780416

  4. Antibiotic sensitivity pattern in blaNDM-1-positive and carbapenemase-producing Enterobacteriaceae

    PubMed Central

    Mulla, Summaiya; Charan, Jaykaran; Rajdev, Sangita

    2016-01-01

    Background: Some studies published in recent time revealed that many bacteria from Enterobacteriaceae group are multi-antibiotic-resistant because of the production enzymes carbapenemase particularly New Delhi metallo-beta-lactamase encoded by gene called blaNDM-1. Looking at public health importance of this issue there is a need for studies at other centers to confirm or refute published findings. Objectives: This study was designed with the aim of exploring antibiotic resistance in Enterobacteriaceae group of bacteria and also to explore gene and enzyme responsible for it. Materials and Methods: Samples of Enterobacteriaceae were collected from wards and outpatient departments. Antibiotic sensitivity was checked by an automated system (VITEK 2 COMPACT). Carbapenemase production was assessed by Modified Hodge Test. Presence of blaNDM-1 was assessed by polymerase chain reaction. Statistics: Frequency and percentage were used to describe the data. Frequency of sensitivity was compared between carbapenemase producers and noncarbapenemase producers by Fisher's exact test. Results: Forty-seven percent bacteria were found to be producing carbapenemase enzyme. These bacteria were significantly less sensitive to cefoperazone, cefepime, and amikacin. Among carbapenemase-producing organisms, 3% and 6% were resistant to tigecycline and colistin, respectively. Forty percent bacteria were found to be having blaNDM-1 gene. There was a significant difference between blaNDM-1-positive and blaNDM-1-negative for sensitivity toward cefoperazone + sulbactam, imipenem, meropenem, amikacin, tobramycine, ciprofloxacin, and levofloxacin. Conclusion: Presence of carbapenemase enzyme and blaNDM-1 gene is associated with high level of resistance in Enterobacteriaceae group of bacteria and only few antibiotics have good sensitivity for these organisms. PMID:26958516

  5. Crystal Structure of a Dimerized Cockroach Allergen Bla g 2 Complexed with a Monoclonal Antibody

    SciTech Connect

    Li, Mi; Gustchina, Alla; Alexandratos, Jerry; Wlodawer, Alexander; Wünschmann, Sabina; Kepley, Christopher L.; Chapman, Martin D.; Pomes, Anna

    2008-09-03

    The crystal structure of a 1:1 complex between the German cockroach allergen Bla g 2 and the Fab' fragment of a monoclonal antibody 7C11 was solved at 2.8-{angstrom} resolution. Bla g 2 binds to the antibody through four loops that include residues 60-70, 83-86, 98-100, and 129-132. Cation-{pi} interactions exist between Lys-65, Arg-83, and Lys-132 in Bla g 2 and several tyrosines in 7C11. In the complex with Fab', Bla g 2 forms a dimer, which is stabilized by a quasi-four-helix bundle comprised of an {alpha}-helix and a helical turn from each allergen monomer, exhibiting a novel dimerization mode for an aspartic protease. A disulfide bridge between C51a and C113, unique to the aspartic protease family, connects the two helical elements within each Bla g 2 monomer, thus facilitating formation of the bundle. Mutation of these cysteines, as well as the residues Asn-52, Gln-110, and Ile-114, involved in hydrophobic interactions within the bundle, resulted in a protein that did not dimerize. The mutant proteins induced less {beta}-hexosaminidase release from mast cells than the wild-type Bla g 2, suggesting a functional role of dimerization in allergenicity. Because 7C11 shares a binding epitope with IgE, the information gained by analysis of the crystal structure of its complex provided guidance for site-directed mutagenesis of the allergen epitope. We have now identified key residues involved in IgE antibody binding; this information will be useful for the design of vaccines for immunotherapy.

  6. Klebsiella pneumoniae carrying blaNDM-1 gene in orthopedic practice

    PubMed Central

    Gupta, Varsha; Bansal, Neha; Gupta, Ravi; Chander, Jagdish

    2014-01-01

    Emergence and spread of carbapenemases in Enterobacteriaceae is a cause of concern worldwide, the latest threat being New Delhi metallo-β-lactamase (NDM-1). This report is of an orthopedic case with fracture femur managed with internal fixation and bone grafting, who subsequently developed secondary infection with Klebsiella pneumoniae harboring blaNDM-1 gene. Minimum inhibitory concentration (MIC) of imipenem was ≥8 μg/ml by E-test, suggestive of carbapenemase production. Phenotypic and further genotypic detection confirmed the presence of blaNDM-1 gene. The isolate remained susceptible only to tigecycline, colistin, and polymyxin B. PMID:25298566

  7. New Small Plasmid Harboring blaKPC-2 in Pseudomonas aeruginosa.

    PubMed

    Galetti, Renata; Andrade, Leonardo Neves; Chandler, Michael; Varani, Alessandro de Mello; Darini, Ana Lúcia Costa

    2016-05-01

    The aim of this study was to characterize the genetic context of blaKPC-2 in Pseudomonas aeruginosa sequence type 244 from Brazil. The blaKPC-2 gene was detected in a new small plasmid, pBH6. Complete sequencing revealed that pBH6 was 3,652 bp long and included the Tn3 resolvase and Tn3 inverted repeat (IR), a partial copy of ISKpn6, and a putative ori region but no rep genes. pBH6 replicated stably into Escherichia coli strain DH10B and P. aeruginosa strain PAO. PMID:26953192

  8. Clonal spread of blaOXA-72-carrying Acinetobacter baumannii sequence type 512 in Taiwan.

    PubMed

    Kuo, Han-Yueh; Hsu, Po-Jui; Chen, Jiann-Yuan; Liao, Po-Cheng; Lu, Chia-Wei; Chen, Chang-Hua; Liou, Ming-Li

    2016-07-01

    This is the first report to show an insidious outbreak of armA- and blaOXA-72-carrying Acinetobacter baumannii sequence type 512 (ST512) at a study hospital in northern Taiwan. Multilocus sequence typing revealed that this was a ST512 clone. All of the isolates with ST512 carried a novel 12,056-bp repGR2 in combination with a repGR12-type plasmid. This plasmid, designated pAB-ML, had one copy of the blaOXA-72 gene that was flanked by XerC/XerD-like sites and conferred resistance to carbapenems. PMID:27242318

  9. Complete Genome Sequence of a Klebsiella pneumoniae Strain Carrying blaNDM-1 on a Multidrug Resistance Plasmid

    PubMed Central

    Lau, Anna F.; Palmore, Tara N.; Frank, Karen M.; Segre, Julia A.

    2016-01-01

    Here, we report the genome sequence of a blaNDM-1-positive Klebsiella pneumoniae AATZP isolate cultured from a perirectal surveillance swab collected upon admission of a patient to the NIH Clinical Center in 2014. Genome sequencing of this isolate revealed three plasmids, including one carrying the blaNDM-1 gene encoding resistance to carbapenems. PMID:27417839

  10. Genomic Characteristics of NDM-Producing Enterobacteriaceae Isolates in Australia and Their blaNDM Genetic Contexts

    PubMed Central

    Wailan, Alexander M.; Paterson, David L.; Kennedy, Karina; Ingram, Paul R.; Bursle, Evan

    2015-01-01

    blaNDM has been reported in different Enterobacteriaceae species and on numerous plasmid replicon types (Inc). Plasmid replicon typing, in combination with genomic characteristics of the bacterial host (e.g., sequence typing), is used to infer the spread of antimicrobial resistance determinants between genetically unrelated bacterial hosts. The genetic context of blaNDM is heterogeneous. In this study, we genomically characterized 12 NDM-producing Enterobacteriaceae isolated in Australia between 2012 and 2014: Escherichia coli (n = 6), Klebsiella pneumoniae (n = 3), Enterobacter cloacae (n = 2) and Providencia rettgeri (n = 1). We describe their blaNDM genetic contexts within Tn125, providing insights into the acquisition of blaNDM into Enterobacteriaceae. IncFII-type (n = 7) and IncX3 (n = 4) plasmids were the most common plasmid types found. The IncHI1B (n = 1) plasmid was also identified. Five different blaNDM genetic contexts were identified, indicating four particular plasmids with specific blaNDM genetic contexts (NGCs), three of which were IncFII plasmids (FII-A to -C). Of note, the blaNDM genetic context of P. rettgeri was not conjugative. Epidemiological links between our NDM-producing Enterobacteriaceae were established by their acquisition of these five particular plasmid types. The combination of different molecular and genetic characterization methods allowed us to provide insight into the spread of plasmids transmitting blaNDM. PMID:26482302

  11. Genomic Characteristics of NDM-Producing Enterobacteriaceae Isolates in Australia and Their blaNDM Genetic Contexts.

    PubMed

    Wailan, Alexander M; Paterson, David L; Kennedy, Karina; Ingram, Paul R; Bursle, Evan; Sidjabat, Hanna E

    2016-01-01

    blaNDM has been reported in different Enterobacteriaceae species and on numerous plasmid replicon types (Inc). Plasmid replicon typing, in combination with genomic characteristics of the bacterial host (e.g., sequence typing), is used to infer the spread of antimicrobial resistance determinants between genetically unrelated bacterial hosts. The genetic context of blaNDM is heterogeneous. In this study, we genomically characterized 12 NDM-producing Enterobacteriaceae isolated in Australia between 2012 and 2014: Escherichia coli (n = 6), Klebsiella pneumoniae (n = 3), Enterobacter cloacae (n = 2) and Providencia rettgeri (n = 1). We describe their blaNDM genetic contexts within Tn125, providing insights into the acquisition of blaNDM into Enterobacteriaceae. IncFII-type (n = 7) and IncX3 (n = 4) plasmids were the most common plasmid types found. The IncHI1B (n = 1) plasmid was also identified. Five different blaNDM genetic contexts were identified, indicating four particular plasmids with specific blaNDM genetic contexts (NGCs), three of which were IncFII plasmids (FII-A to -C). Of note, the blaNDM genetic context of P. rettgeri was not conjugative. Epidemiological links between our NDM-producing Enterobacteriaceae were established by their acquisition of these five particular plasmid types. The combination of different molecular and genetic characterization methods allowed us to provide insight into the spread of plasmids transmitting blaNDM. PMID:26482302

  12. Increased waterborne blaNDM-1 resistance gene abundances associated with seasonal human pilgrimages to the upper ganges river.

    PubMed

    Ahammad, Z S; Sreekrishnan, T R; Hands, C L; Knapp, C W; Graham, D W

    2014-01-01

    Antibiotic resistance (AR) is often rooted in inappropriate antibiotic use, but poor water quality and inadequate sanitation exacerbate the problem, especially in emerging countries. An example is increasing multi-AR due to mobile carbapenemases, such as NDM-1 protein (coded by blaNDM-1 genes), which can produce extreme drug-resistant phenotypes. In 2010, NDM-1 positive isolates and blaNDM-1 genes were detected in surface waters across Delhi and have since been detected across the urban world. However, little is known about blaNDM-1 levels in more pristine locations, such as the headwaters of the Upper Ganges River. This area is of particular interest because it receives massive numbers of visitors during seasonal pilgrimages in May/June, including visitors from urban India. Here we quantified blaNDM-1 abundances, other AR genes (ARG), and coliform bacteria in sediments and water column samples from seven sites in the Rishikesh-Haridwar region of the Upper Ganges and five sites on the Yamuna River in Delhi to contrast blaNDM-1 levels and water quality conditions between season and region. Water quality in the Yamuna was very poor (e.g., anoxia at all sites), and blaNDM-1 abundances were high across sites in water (5.4 ± 0.4 log(blaNDM-1·mL(-1)); 95% confidence interval) and sediment (6.3 ± 0.7 log(blaNDM-1·mg(-1))) samples from both seasons. In contrast, water column blaNDM-1 abundances were very low across all sites in the Upper Ganges in February (2.1 ± 0.6 log(blaNDM-1·mL(-1))), and water quality was good (e.g., near saturation oxygen). However, per capita blaNDM-1 levels were 20 times greater in June in the Ganges water column relative to February, and blaNDM-1 levels significantly correlated with fecal coliform levels (r = 0.61; p = 0.007). Given that waste management infrastructure is limited in Rishikesh-Haridwar, data imply blaNDM-1 levels are higher in visitor's wastes than local residents, which results in seasonally higher blaNDM-1 levels in the

  13. Increased Waterborne blaNDM-1 Resistance Gene Abundances Associated with Seasonal Human Pilgrimages to the Upper Ganges River

    PubMed Central

    2014-01-01

    Antibiotic resistance (AR) is often rooted in inappropriate antibiotic use, but poor water quality and inadequate sanitation exacerbate the problem, especially in emerging countries. An example is increasing multi-AR due to mobile carbapenemases, such as NDM-1 protein (coded by blaNDM-1 genes), which can produce extreme drug-resistant phenotypes. In 2010, NDM-1 positive isolates and blaNDM-1 genes were detected in surface waters across Delhi and have since been detected across the urban world. However, little is known about blaNDM-1 levels in more pristine locations, such as the headwaters of the Upper Ganges River. This area is of particular interest because it receives massive numbers of visitors during seasonal pilgrimages in May/June, including visitors from urban India. Here we quantified blaNDM-1 abundances, other AR genes (ARG), and coliform bacteria in sediments and water column samples from seven sites in the Rishikesh-Haridwar region of the Upper Ganges and five sites on the Yamuna River in Delhi to contrast blaNDM-1 levels and water quality conditions between season and region. Water quality in the Yamuna was very poor (e.g., anoxia at all sites), and blaNDM-1 abundances were high across sites in water (5.4 ± 0.4 log(blaNDM-1·mL–1); 95% confidence interval) and sediment (6.3 ± 0.7 log(blaNDM-1·mg–1)) samples from both seasons. In contrast, water column blaNDM-1 abundances were very low across all sites in the Upper Ganges in February (2.1 ± 0.6 log(blaNDM-1·mL–1)), and water quality was good (e.g., near saturation oxygen). However, per capita blaNDM-1 levels were 20 times greater in June in the Ganges water column relative to February, and blaNDM-1 levels significantly correlated with fecal coliform levels (r = 0.61; p = 0.007). Given that waste management infrastructure is limited in Rishikesh-Haridwar, data imply blaNDM-1 levels are higher in visitor’s wastes than local residents, which results in seasonally higher blaNDM-1 levels in the

  14. US biosimilar pathway unlikely to be used: developers will opt for a traditional BLA filing.

    PubMed

    Wiatr, Claudia

    2011-02-01

    In March 2010, the US passed the healthcare reform bill, including The Biologics Price Competition and Innovation Act of 2009, which established an abbreviated Biologic License Application (aBLA) pathway for the approval of biosimilars. The aBLA pathway may never be used. At the "Business of Biosimilars" meeting in Boston in September, developers of both innovator and generic biologics as well as representatives from the scientific, regulatory, and legal communities noted that, because of unclear requirements for clinical data and the need for public disclosure of proprietary data, manufacturers of generic biologics are unlikely to take advantage of the aBLA process, opting instead for a standard Biologic License Application (BLA). The implications of an unusable biosimilars pathway in the US dampen our already soft outlook for biosimilars. Companies will still develop follow-on biologics, but approved compounds will behave as new branded drugs. Biosimilars in the US are therefore not likely to lead to aggressive pricing, but will more likely mirror current situations where several similar biologics are available. For example, the interferon (IFN) β-1a products Avonex® and Rebif®, and Betaseron® (IFN β-1b) have all enjoyed >10% price increases for the last several years in spite of their clinical similarities. inThought reiterates its outlook for generic erosion of a typical biologic that projects a loss of revenue of 30% over 5 years compared to the 90% revenue loss for a typical branded small molecule. PMID:21222498

  15. DHPG Activation of Group 1 mGluRs in BLA Enhances Fear Conditioning

    ERIC Educational Resources Information Center

    Rudy, Jerry W.; Matus-Amat, Patricia

    2009-01-01

    Group 1 metabotropic glutamate receptors are known to play an important role in both synaptic plasticity and memory. We show that activating these receptors prior to fear conditioning by infusing the group 1 mGluR agonist, (R.S.)-3,5-dihydroxyphenylglycine (DHPG), into the basolateral region of the amygdala (BLA) of adult Sprague-Dawley rats…

  16. Molecular Characterization by Using Next-Generation Sequencing of Plasmids Containing blaNDM-7 in Enterobacteriaceae from Calgary, Canada.

    PubMed

    Chen, L; Peirano, G; Lynch, T; Chavda, K D; Gregson, D B; Church, D L; Conly, J; Kreiswirth, B N; Pitout, J D

    2016-03-01

    Enterobacteriaceae with blaNDM-7 are relatively uncommon and had previously been described in Europe, India, the United States, and Japan. This study describes the characteristics of Enterobacteriaceae (Klebsiella pneumoniae [n = 2], Escherichia coli [n = 2], Serratia marcescens [n = 1], and Enterobacter hormaechei [n = 1] isolates) with blaNDM-7 obtained from 4 patients from Calgary, Canada, from 2013 to 2014. The 46,161-bp IncX3 plasmids with blaNDM-7 are highly similar to other blaNDM-harboring IncX3 plasmids and, interestingly, showed identical structures within the different isolates. This finding may indicate horizontal transmission within our health region, or it may indicate contact with individuals from areas of endemicity within the hospital setting. Patients infected or colonized with bacteria containing blaNDM-7 IncX3 plasmids generate infection control challenges. Epidemiological and molecular studies are required to better understand the dynamics of transmission, the risk factors, and the reservoirs for bacteria harboring blaNDM-7. To the best of our knowledge, this is the first report of S. marcescens and E. hormaechei with blaNDM-7. PMID:26643346

  17. Colistin-Nonsusceptible Pseudomonas aeruginosa Sequence Type 654 with blaNDM-1 Arrives in North America

    PubMed Central

    Mataseje, L. F.; Peirano, G.; Church, D. L.; Conly, J.; Mulvey, M.

    2016-01-01

    This study describes 3 different blaNDM-1 genetic platforms in 3 different species obtained from the same patient who was directly transferred to an institution in Calgary, Alberta, Canada, following a prolonged hospital stay in India. The blaNDM-1 in the Escherichia coli isolate was located on a 176-kb IncA/C plasmid contained within an ISCR1 region. The blaNDM-1 in the Providencia rettgeri isolate was located on a 117-kb IncT plasmid contained within Tn3000, while the blaNDM-1 in the Pseudomonas aeruginosa isolate was located on the chromosome within an ISCR3 region. This report highlights the plasticity of the genetic regions and environments associated with blaNDM-1. To the best of our knowledge, this is the first report of P. aeruginosa with blaNDM-1 identified in North America and the first report of blaOXA-181 in P. rettgeri. The P. aeruginosa isolate belonged to the international high-risk sequence type 654 clone and was nonsusceptible to colistin. This case emphasizes the need for the use of appropriate infection prevention and control measures and vigilant screening for carbapenem-resistant Gram-negative bacteria in patients with a history of travel to areas of endemicity, such as the Indian subcontinent. PMID:26824951

  18. Colistin-Nonsusceptible Pseudomonas aeruginosa Sequence Type 654 with blaNDM-1 Arrives in North America.

    PubMed

    Mataseje, L F; Peirano, G; Church, D L; Conly, J; Mulvey, M; Pitout, J D

    2016-03-01

    This study describes 3 different blaNDM-1 genetic platforms in 3 different species obtained from the same patient who was directly transferred to an institution in Calgary, Alberta, Canada, following a prolonged hospital stay in India. The blaNDM-1 in the Escherichia coli isolate was located on a 176-kb IncA/C plasmid contained within an ISCR1 region. The blaNDM-1 in the Providencia rettgeri isolate was located on a 117-kb IncT plasmid contained within Tn3000, while the blaNDM-1 in the Pseudomonas aeruginosa isolate was located on the chromosome within an ISCR3 region. This report highlights the plasticity of the genetic regions and environments associated with blaNDM-1. To the best of our knowledge, this is the first report of P. aeruginosa with blaNDM-1 identified in North America and the first report of blaOXA-181 in P. rettgeri. The P. aeruginosa isolate belonged to the international high-risk sequence type 654 clone and was nonsusceptible to colistin. This case emphasizes the need for the use of appropriate infection prevention and control measures and vigilant screening for carbapenem-resistant Gram-negative bacteria in patients with a history of travel to areas of endemicity, such as the Indian subcontinent. PMID:26824951

  19. Hydrolysis of Clavulanate by Mycobacterium tuberculosis β-Lactamase BlaC Harboring a Canonical SDN Motif

    PubMed Central

    Soroka, Daria; Li de la Sierra-Gallay, Inès; Dubée, Vincent; Triboulet, Sébastien; van Tilbeurgh, Herman; Compain, Fabrice; Ballell, Lluis; Barros, David; Mainardi, Jean-Luc

    2015-01-01

    Combinations of β-lactams with clavulanate are currently being investigated for tuberculosis treatment. Since Mycobacterium tuberculosis produces a broad spectrum β-lactamase, BlaC, the success of this approach could be compromised by the emergence of clavulanate-resistant variants, as observed for inhibitor-resistant TEM variants in enterobacteria. Previous analyses based on site-directed mutagenesis of BlaC have led to the conclusion that this risk was limited. Here, we used a different approach based on determination of the crystal structure of β-lactamase BlaMAb of Mycobacterium abscessus, which efficiently hydrolyzes clavulanate. Comparison of BlaMAb and BlaC allowed for structure-assisted site-directed mutagenesis of BlaC and identification of the G132N substitution that was sufficient to switch the interaction of BlaC with clavulanate from irreversible inactivation to efficient hydrolysis. The substitution, which restored the canonical SDN motif (SDG→SDN), allowed for efficient hydrolysis of clavulanate, with a more than 104-fold increase in kcat (0.41 s−1), without affecting the hydrolysis of other β-lactams. Mass spectrometry revealed that acylation of BlaC and of its G132N variant by clavulanate follows similar paths, involving sequential formation of two acylenzymes. Decarboxylation of the first acylenzyme results in a stable secondary acylenzyme in BlaC, whereas hydrolysis occurs in the G132N variant. The SDN/SDG polymorphism defines two mycobacterial lineages comprising rapidly and slowly growing species, respectively. Together, these results suggest that the efficacy of β-lactam–clavulanate combinations may be limited by the emergence of resistance. β-Lactams active without clavulanate, such as faropenem, should be prioritized for the development of new therapies. PMID:26149997

  20. Hydrolysis of clavulanate by Mycobacterium tuberculosis β-lactamase BlaC harboring a canonical SDN motif.

    PubMed

    Soroka, Daria; Li de la Sierra-Gallay, Inès; Dubée, Vincent; Triboulet, Sébastien; van Tilbeurgh, Herman; Compain, Fabrice; Ballell, Lluis; Barros, David; Mainardi, Jean-Luc; Hugonnet, Jean-Emmanuel; Arthur, Michel

    2015-09-01

    Combinations of β-lactams with clavulanate are currently being investigated for tuberculosis treatment. Since Mycobacterium tuberculosis produces a broad spectrum β-lactamase, BlaC, the success of this approach could be compromised by the emergence of clavulanate-resistant variants, as observed for inhibitor-resistant TEM variants in enterobacteria. Previous analyses based on site-directed mutagenesis of BlaC have led to the conclusion that this risk was limited. Here, we used a different approach based on determination of the crystal structure of β-lactamase BlaMAb of Mycobacterium abscessus, which efficiently hydrolyzes clavulanate. Comparison of BlaMAb and BlaC allowed for structure-assisted site-directed mutagenesis of BlaC and identification of the G(132)N substitution that was sufficient to switch the interaction of BlaC with clavulanate from irreversible inactivation to efficient hydrolysis. The substitution, which restored the canonical SDN motif (SDG→SDN), allowed for efficient hydrolysis of clavulanate, with a more than 10(4)-fold increase in k cat (0.41 s(-1)), without affecting the hydrolysis of other β-lactams. Mass spectrometry revealed that acylation of BlaC and of its G(132)N variant by clavulanate follows similar paths, involving sequential formation of two acylenzymes. Decarboxylation of the first acylenzyme results in a stable secondary acylenzyme in BlaC, whereas hydrolysis occurs in the G(132)N variant. The SDN/SDG polymorphism defines two mycobacterial lineages comprising rapidly and slowly growing species, respectively. Together, these results suggest that the efficacy of β-lactam-clavulanate combinations may be limited by the emergence of resistance. β-Lactams active without clavulanate, such as faropenem, should be prioritized for the development of new therapies. PMID:26149997

  1. Nosocomial dissemination of plasmids carrying blaTEM-24, blaDHA-1, aac(6')-Ib-cr, and qnrA6 in Providencia spp. strains isolated from a Tunisian hospital.

    PubMed

    Mahrouki, Sihem; Chihi, Hela; Bourouis, Amel; Ayari, Khaoula; Ferjani, Mustapha; Moussa, Mohamed Ben; Belhadj, Omrane

    2015-01-01

    The aim of this study is to report the emergence of IncA/C conjugative plasmids harboring blaTEM-24, blaDHA-1, qnrA6, and aac(6')-Ib-cr genes among Providencia spp. isolates recovered in 2008 in Tunisia. The double-disk synergy test confirmed the phenotype extended-spectrum β-lactamase (ESBL) in 2 Providencia stuartii and 5 Providencia rettgeri. These ESBLs were coresistant to cefoxitin, chloramphenicol, ofloxacin, and sulfonamides but remained susceptible to imipenem. Three β-lactamases TEM-2, TEM-24, and DHA-1 were detected. blaTEM-24, blaDHA-1, aac(6')-Ib-cr, and qnrA6 genes were successfully transferred to Escherichia coli strain HB101, and they were found located on the conjugatifs IncA/C plasmids. Genetic relatedness showed similar and different patterns among P. stuartii and P. rettgeri strains, respectively. PMID:25315769

  2. Complete Nucleotide Sequences of blaKPC-4- and blaKPC-5-Harboring IncN and IncX Plasmids from Klebsiella pneumoniae Strains Isolated in New Jersey

    PubMed Central

    Chen, Liang; Chavda, Kalyan D.; Fraimow, Henry S.; Mediavilla, José R.; Melano, Roberto G.; Jacobs, Michael R.; Bonomo, Robert A.

    2013-01-01

    Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae have emerged as major nosocomial pathogens. blaKPC, commonly located on Tn4401, is found in Gram-negative bacterial strains, with the two most common variants, blaKPC-2 and blaKPC-3, identified in plasmids with diverse genetic backgrounds. In this study, we examined blaKPC-4- and blaKPC-5-bearing plasmids recovered from two K. pneumoniae strains, which were isolated from a single New Jersey hospital in 2005 and 2006, respectively. IncN plasmid pBK31551 is 84 kb in length and harbors blaKPC-4, blaTEM-1, qnrB2, aac(3)-Ib, aph(3′)-I, qacF, qacEΔ1, sul1, and dfrA14, which confer resistance to β-lactams, quinolones, aminoglycosides, quaternary ammonium compounds, and co-trimoxazole. The conserved regions within pBK31551 are similar to those of other IncN plasmids. Surprisingly, analysis of the Tn4401 sequence revealed a large IS110- and Tn6901-carrying element (8.3 kb) inserted into the istA gene, encoding glyoxalase/bleomycin resistance, alcohol dehydrogenase, and S-formylglutathione hydrolase. Plasmid pBK31567 is 47 kb in length and harbors blaKPC-5, dfrA5, qacEΔ1, and sul1. pBK31567 belongs to a novel IncX subgroup (IncX5) and possesses a highly syntenic plasmid backbone like other IncX plasmids; however, sequence similarity at the nucleotide level is divergent. The blaKPC-5 gene is carried on a Tn4401 element and differs from the genetic environment of blaKPC-5 described in Pseudomonas aeruginosa strain P28 from Puerto Rico. This study underscores the genetic diversity of multidrug-resistant plasmids involved in the spread of blaKPC genes and highlights the mobility and plasticity of Tn4401. Comparative genomic analysis provides new insights into the evolution and dissemination of KPC plasmids belonging to different incompatibility groups. PMID:23114770

  3. Isolation of Enterobacter aerogenes carrying blaTEM-1 and blaKPC-3 genes recovered from a hospital Intensive Care Unit.

    PubMed

    Pulcrano, Giovanna; Pignanelli, Salvatore; Vollaro, Adriana; Esposito, Matilde; Iula, Vita Dora; Roscetto, Emanuela; Soriano, Amata Amy; Catania, Maria Rosaria

    2016-06-01

    Enterobacter aerogenes has recently emerged as an important hospital pathogen. In this study, we showed the emergence of E. aerogenes isolates carrying the blaKPC gene in patients colonized by carbapenem-resistant Klebsiella pneumoniae strains. Two multiresistant E. aerogenes isolates were recovered from bronchial aspirates of two patients hospitalized in the Intensive Care Unit at the "Santa Maria della Scaletta" Hospital, Imola. The antimicrobial susceptibility test showed the high resistance to carbapenems and double-disk synergy test confirmed the phenotype of KPC and AmpC production. Other investigation revealed that ESBL and blaKPC genes were carried on the conjugative pKpQIL plasmid. This is a relevant report in Italy that describes a nosocomial infection due to the production of KPC beta-lactamases by an E. aerogenes isolate in patients previously colonized by K. pneumoniae carbapenem-resistant. In conclusion, it's necessary a continuous monitoring of multidrug-resistant strains for the detection of any KPC-producing bacteria that could expand the circulation of carbapenem-resistant pathogens. PMID:27004836

  4. Antibiotic Resistance Pattern and Evaluation of Metallo-Beta Lactamase Genes Including bla-IMP and bla-VIM Types in Pseudomonas aeruginosa Isolated from Patients in Tehran Hospitals

    PubMed Central

    Aghamiri, Samira; Amirmozafari, Nour; Fallah Mehrabadi, Jalil; Fouladtan, Babak; Samadi Kafil, Hossein

    2014-01-01

    Beta-lactamase producing strains of Pseudomonas aeruginosa are important etiological agents of hospital infections. Carbapenems are among the most effective antibiotics used against Pseudomonas infections, but they can be rendered infective by group B β-lactamase, commonly called metallo-beta lactamase. In this study, the antimicrobial sensitivity patterns of P. aeruginosa strains isolated from 9 different hospitals in Tehran, Iran, as well as the prevalence of MBLs genes (bla-VIM and bla-IMP) were determined. A total of 212 strains of P. aeruginosa recovered from patients in hospitals in Tehran were confirmed by both biochemical methods and PCR. Their antimicrobial sensitivity patterns were determined by Kirby-Bauer disk diffusion method. Following MIC determination, imipenem resistant strains were selected by DDST method which was followed by PCR tests for determination of MBLs genes: bla-IMP and bla-VIM. The results indicated that, in the DDST phenotypic method, among the 100 imipenem resistant isolates, 75 strains were MBLs positive. The PCR test indicated that 70 strains (33%) carried bla-VIM gene and 20 strains (9%) harbored bla-IMP. The results indicated that the extent of antibiotic resistance among Pseudomonas aeruginosa is on the rise. This may be due to production of MBLs enzymes. Therefore, determination of antibiotic sensitivity patterns and MBLs production by these bacteria, can be important in control of clinical Pseudomonas infection. PMID:24944839

  5. Complete Sequences of Two Plasmids in a blaNDM-1-Positive Klebsiella oxytoca Isolate from Taiwan

    PubMed Central

    Huang, Tzu-Wen; Wang, Jann-Tay; Lauderdale, Tsai-Ling; Liao, Tsai-Lien; Lai, Jui-Fen; Tan, Mei-Chen; Lin, Ann-Chi; Chen, Ying-Tsong; Tsai, Shih-Feng

    2013-01-01

    Genetic determinants of a blaNDM-1-positive, multidrug-resistant bacterial isolate that caused active infection was investigated by DNA sequencing. Two plasmids, pKOX_NDM1 and pKOX-R1, were identified for the Klebsiella oxytoca strain E718. Sequence annotation revealed a blaNDM-1 gene in pKOX_NDM1 and two extended-spectrum β-lactamase producers (blaCTX-M-3 and blaSHV-12) and a wide array of resistance genes in pKOX-R1. These findings highlight the difficulty in treating multidrug-resistant bacterial infections and the potential danger of emerging resistant enterobacteria. PMID:23752513

  6. Expression of blaA Underlies Unexpected Ampicillin-Induced Cell Lysis of Shewanella oneidensis

    PubMed Central

    Yin, Jianhua; Sun, Linlin; Dong, Yangyang; Chi, Xun; Zhu, Weiming; Qi, Shu-hua; Gao, Haichun

    2013-01-01

    Shewanella oneidensis is a facultative anaerobic γ-proteobacterium possessing remarkably diverse respiratory capacities for reducing various organic and inorganic substrates. As a veteran research model for investigating redox transformations of environmental contaminants the bacterium is well known to be a naturally ampicillin-resistant microorganism. However, in this study we discovered that ampicillin has a significant impact on growth of S. oneidensis. Particularly, cell lysis occurred only with ampicillin at levels ranging from 0.49 to 6.25 µg/ml but not at 50 µg/ml. This phenotype is attributable to insufficient expression of the β-lactamase BlaA. The subsequent analysis revealed that the blaA gene is strongly induced by ampicillin at high (50 µg/ml), but not at low levels (2.5 µg/ml). In addition, we demonstrated that penicillin binding protein 5 (PBP5), the most abundant low molecular weight PBP (LMW PBP), is the only one relevant to β-lactam resistance under the tested conditions. This nonessential PBP, largely resembling its Escherichia coli counterpart in functionality, mediates expression of the blaA gene. PMID:23555975

  7. Human β-defensin HBD3 binds to immobilized Bla g2 from the German cockroach (Blattella germanica).

    PubMed

    Dietrich, Deborah E; Martin, Aaron D; Brogden, Kim A

    2014-03-01

    Human β-defensin 3 (HBD3) is a small, well-characterized peptide in mucosal secretions with broad antimicrobial activities and diverse innate immune functions. Among these functions is the ability of HBD3 to bind to antigens. In this study, we hypothesize that HBD3 binds to the allergen Bla g2 from the German cockroach (Blattella germanica). The ability of HBD1 (used as a control β-defensin) and HBD3 to bind to Bla g2 and human serum albumin (HSA, used as a control ligand) was assessed using the SensíQ Pioneer surface plasmon resonance (SPR) spectroscopy biosensor system. HBD1 was observed to bind weakly to Bla g2, while HBD3 demonstrated a stronger affinity for the allergen. HBD3 was assessed under two buffer conditions using 0.15 M and 0.3 M NaCl to control the electrostatic attraction of the peptide to the chip surface. The apparent K(D) of HBD3 binding Bla g2 was 5.9±2.1 μM and for binding HSA was 4.2±0.7 μM, respectively. Thus, HBD3, found in mucosal secretions has the ability to bind to allergens like Bla g2 possibly by electrostatic interaction, and may alter the ability of Bla g2 to induce localized allergic and/or inflammatory mucosal responses. PMID:24495736

  8. Cockroach allergen Bla g 7 promotes TIM4 expression in dendritic cells leading to Th2 polarization.

    PubMed

    Xu, Lingxiao; Zhang, Miaojia; Ma, Wenjing; Jin, Shanshan; Song, Weijuan; He, Shaoheng

    2013-01-01

    As one of the most common sources of indoor aeroallergens worldwide, cockroach is important in causing rhinitis and asthma while the mechanisms underlying remain obscure. Since T helper (Th) type 2 polarization plays an important role in the pathogenesis of allergic diseases, we investigated the effect of Bla g 7, a pan-allergen from Blattella germanica (B. germanica), on Th polarization which is controlled by monocyte-derived dendritic cells (DCs). Challenged by recombinant Bla g 7 (rBla g 7), immature DCs obtained from human exhibited upregulated levels of TIM4, CD80, and CD86 and increased IL-13 secretion. Cocultured with CD4+ T cells, challenged DCs increased the ratio of IL-4+ versus IFN-γ+ of CD4+ T cells, suggesting a balance shift from Th1 to Th2. Moreover, antibodies against TIM4, CD80, and CD86 reversed the enhancement of IL-4+/IFN-γ+ ratio and alleviated the IL-13 release induced by rBla g 7, indicating that the Th2 polarization provoked by rBla g 7 challenged DCs is via TIM4-, CD80-, and CD86-dependent mechanisms. In conclusion, the present findings implied a crucial role of Bla g 7 in the development of cockroach allergy and highlighted an involvement of DCs-induced Th2 polarization in cockroach allergy. PMID:24204099

  9. An outbreak of blaOXA-51-like- and blaOXA-66-positive Acinetobacter baumannii ST208 in the emergency intensive care unit

    PubMed Central

    Umezawa, Kazuo; Iwashita, Hideo; Ohshima, Toshio; Ohashi, Maya; Sasaki, Mika; Hayashi, Hideki; Matsui, Mari; Shibayama, Keigo; Inokuchi, Sadaki; Miyachi, Hayato

    2014-01-01

    A series of clinical isolates of drug-resistant (DR) Acinetobacter baumannii with diverse drug susceptibility was detected from eight patients in the emergency intensive care unit of Tokai University Hospital. The initial isolate was obtained in March 2010 (A. baumannii Tokai strain 1); subsequently, seven isolates were obtained from patients (A. baumannii Tokai strains 2–8) and one isolate was obtained from an air-fluidized bed used by five of the patients during the 3 months from August to November 2011. The isolates were classified into three types of antimicrobial drug resistance patterns (RRR, SRR and SSR) according to their susceptibility (S) or resistance (R) to imipenem, amikacin and ciprofloxacin, respectively. Genotyping of these isolates by multilocus sequence typing revealed one sequence type, ST208, whilst that by a DiversiLab analysis revealed two subtypes. All the isolates were positive for blaOXA-51-like and blaOXA-66, as assessed by PCR and DNA sequencing. A. baumannii Tokai strains 1–8 and 10 (RRR, SRR and SSR) had quinolone resistance-associated mutations in gyrA/parC, as revealed by DNA sequencing. The ISAba1 upstream of blaOXA-51-like and aminoglycoside resistance-associated gene, armA, were detected in A. baumannii Tokai strains 1–7 and 10 (RRR and SRR) as assessed by PCR. Among the genes encoding resistance–nodulation–division family pumps (adeB, adeG and adeJ) and outer-membrane porins (oprD and carO), overexpression of adeB and adeJ and suppression of oprD and carO were seen in isolates of A. baumannii Tokai strain 2 (RRR), as assessed by real-time PCR. Thus, the molecular characterization of a series of isolates of DR A. baumannii revealed the outbreak of ST208 and diverse antimicrobial drug susceptibilities, which almost correlated with differential gene alterations responsible for each type of drug resistance. PMID:25142965

  10. A Swordless Knight: Epidemiology and Molecular Characteristics of the blaKPC-Negative Sequence Type 258 Klebsiella pneumoniae Clone

    PubMed Central

    Paikin, Svetlana; Sterlin, Yelena; Glick, Josef; Edgar, Rotem; Aronov, Rima; Schwaber, Mitchell J.; Carmeli, Yehuda

    2012-01-01

    In June 2010, a blaKPC-negative, ertapenem-resistant ST-258 Klebsiella pneumoniae strain was isolated from a patient in the Laniado Medical Center (LMC). Our aims were (i) to describe its molecular characteristics and resistance mechanisms and (ii) to assess whether the blaKPC-negative ST-258 K. pneumoniae clone spreads as efficiently as its KPC-producing isogenic strain. In a prospective study, surveillance of all ertapenem-resistant, carbapenemase-negative K. pneumoniae (ERCNKP) isolates was conducted from June 2010 to May 2011 at LMC (314 beds) and from July 2008 to December 2010 at the Tel Aviv Sourasky Medical Center (TASMC) (1,200 beds). Molecular typing was done by arbitrarily primed PCR, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). A total of 8 of 42 (19%) ERCNKP isolates in LMC and 1 of 32 (3.1%) in TASMC belonged to the ST-258 clone. These strains carried the blaCTX-M-2 or the blaCTX-M-25 extended-spectrum β-lactamase (ESBL) gene. Sequencing of the ompK genes showed a frameshift mutation in the ompK35 gene. The fate of the blaKPC-carrying plasmid, pKpQIL, was determined by S1 analysis and by PCR of the Tn4401 transposon, repA, and the truncated blaOXA-9. Plasmid analysis of the ERCNKP ST-258 isolates showed variability in plasmid composition and absence of the Tn4401 transposon and the pKpQIL plasmid. In addition, the ST-258 clone was identified in 35/35 (100%) of KPC-producing K. pneumoniae isolates but in none of 62 ertapenem-susceptible K. pneumoniae isolates collected in the two centers. Our results suggest that ERCNKP ST-258 evolved by loss of the blaKPC-carrying plasmid pKpQIL. ERCNKP ST-258 appears to have low epidemic potential. PMID:22814467

  11. In70 of plasmid pAX22, a bla(VIM-1)-containing integron carrying a new aminoglycoside phosphotransferase gene cassette.

    PubMed

    Riccio, M L; Pallecchi, L; Fontana, R; Rossolini, G M

    2001-04-01

    An Achromobacter xylosoxydans strain showing broad-spectrum resistance to beta-lactams (including carbapenems) and aminoglycosides was isolated at the University Hospital of Verona (Verona, Italy). This strain was found to produce metallo-beta-lactamase activity and to harbor a 30-kb nonconjugative plasmid, named pAX22, carrying a bla(VIM-1) determinant inserted into a class 1 integron. Characterization of this integron, named In70, revealed an original array of four gene cassettes containing, respectively, the bla(VIM-1) gene and three different aminoglycoside resistance determinants, including an aacA4 allele, a new aph-like gene named aphA15, and an aadA1 allele. The aphA15 gene is the first example of an aph-like gene carried on a mobile gene cassette, and its product exhibits close similarity to the APH(3')-IIa aminoglycoside phosphotransferase encoded by Tn5 (36% amino acid identity) and to an APH(3')-IIb enzyme from Pseudomonas aeruginosa (38% amino acid identity). Expression of the cloned aphA15 gene in Escherichia coli reduced the susceptibility to kanamycin and neomycin as well as (slightly) to amikacin, netilmicin, and streptomycin. Characterization of the 5' and 3' conserved segments of In70 and of their flanking regions showed that In70 belongs to the group of class 1 integrons associated with defective transposon derivatives originating from Tn402-like elements. The structure of the 3' conserved segment indicates the closest ancestry with members of the In0-In2 lineage. In70, with its array of cassette-borne resistance genes, can mediate broad-spectrum resistance to most beta-lactams and aminoglycosides. PMID:11257042

  12. In70 of Plasmid pAX22, a blaVIM-1-Containing Integron Carrying a New Aminoglycoside Phosphotransferase Gene Cassette

    PubMed Central

    Riccio, Maria Letizia; Pallecchi, Lucia; Fontana, Roberta; Rossolini, Gian Maria

    2001-01-01

    An Achromobacter xylosoxydans strain showing broad-spectrum resistance to β-lactams (including carbapenems) and aminoglycosides was isolated at the University Hospital of Verona (Verona, Italy). This strain was found to produce metallo-β-lactamase activity and to harbor a 30-kb nonconjugative plasmid, named pAX22, carrying a blaVIM-1 determinant inserted into a class 1 integron. Characterization of this integron, named In70, revealed an original array of four gene cassettes containing, respectively, the blaVIM-1 gene and three different aminoglycoside resistance determinants, including an aacA4 allele, a new aph-like gene named aphA15, and an aadA1 allele. The aphA15 gene is the first example of an aph-like gene carried on a mobile gene cassette, and its product exhibits close similarity to the APH(3′)-IIa aminoglycoside phosphotransferase encoded by Tn5 (36% amino acid identity) and to an APH(3′)-IIb enzyme from Pseudomonas aeruginosa (38% amino acid identity). Expression of the cloned aphA15 gene in Escherichia coli reduced the susceptibility to kanamycin and neomycin as well as (slightly) to amikacin, netilmicin, and streptomycin. Characterization of the 5′ and 3′ conserved segments of In70 and of their flanking regions showed that In70 belongs to the group of class 1 integrons associated with defective transposon derivatives originating from Tn402-like elements. The structure of the 3′ conserved segment indicates the closest ancestry with members of the In0-In2 lineage. In70, with its array of cassette-borne resistance genes, can mediate broad-spectrum resistance to most β-lactams and aminoglycosides. PMID:11257042

  13. Susceptibility Pattern and Distribution of Oxacillinases and blaPER-1 Genes among Multidrug Resistant Acinetobacter baumannii in a Teaching Hospital in Iran

    PubMed Central

    Bagheri Josheghani, Sareh; Moniri, Rezvan; Firoozeh, Farzaneh; Sehat, Mojtaba; Dasteh Goli, Yasaman

    2015-01-01

    Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen in healthcare institutions. β-Lactamase-mediated resistance is the most common mechanism for carbapenem resistance in A. baumannii. The aim of this study was to determine the antibiotic resistance pattern, to detect OXA encoding genes, class A, blaPER-1, and to detect the presence of ISAba1. A total of 124 A. baumannii isolates were collected from hospitalized patients in a teaching hospital in Kashan, Iran. The susceptibility of isolates to different antibiotics was determined by disk-diffusion method. PCR was used to detect blaPER-1, blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, and ISAba1 genes. All isolates were resistant to ceftazidime, ceftriaxone, and cefotaxime. All of the isolates revealed susceptibility to polymyxin B and colistin. Ninety-six percent of the isolates were extensive drug resistance (XDR), 5.6% extended spectrum beta-lactamase (ESBL), and 54.8% metallo-beta-lactamase (MBL). All isolates were positive for blaOXA-51 and ISAba1. blaOXA-23,  blaOXA-24, and blaOXA-58 were found in 79.8%, 25%, and 3.2%, respectively. The frequency rate of blaPER-1 gene was 52.4%. Multidrug resistant A. baumannii isolates are increasing in our setting and extensively limit therapeutic options. The high rate presence of class D carbapenemase-encoding genes, mainly blaOXA-23 carbapenemases, is worrying and alarming as an emerging threat in our hospital. PMID:26881082

  14. Identification of emergent blaCMY-2-carrying Proteus mirabilis lineages by whole-genome sequencing

    PubMed Central

    Mac Aogáin, M.; Rogers, T.R.; Crowley, B.

    2015-01-01

    Whole-genome sequencing of 24 Proteus mirabilis isolates revealed the clonal expansion of two cefoxitin-resistant strains among patients with community-onset infection. These strains harboured blaCMY-2 within a chromosomally located integrative and conjugative element and exhibited multidrug resistance phenotypes. A predominant strain, identified in 18 patients, also harboured the PGI-1 genomic island and associated resistance genes, accounting for its broader antibiotic resistance profile. The identification of these novel multidrug-resistant strains among community-onset infections suggests that they are endemic to this region and represent emergent P. mirabilis lineages of clinical significance. PMID:26865983

  15. Rapid point-of-care detection of the tuberculosis pathogen using a BlaC-specific fluorogenic probe

    PubMed Central

    Xie, Hexin; Mire, Joseph; Kong, Ying; Chang, MiHee; Hassounah, Hany A.; Thornton, Chris N.; Sacchettini, James C.; Cirillo, Jeffrey D.; Rao, Jianghong

    2014-01-01

    Early diagnosis of tuberculosis can dramatically reduce both its transmission and the associated death rate. The extremely slow growth rate of the causative pathogen, Mycobacterium tuberculosis (Mtb), however, makes this challenging at the point of care, particularly in resource-limited settings. Here we report the use of BlaC (an enzyme naturally expressed/secreted by tubercle bacilli) as a marker and the design of BlaC-specific fluorogenic substrates as probes for Mtb detection. These probes showed an enhancement by 100–200 times in fluorescence emission on BlaC activation and a greater than 1,000-fold selectivity for BlaC over TEM-1 β-lactamase, an important factor in reducing false-positive diagnoses. Insight into the BlaC specificity was revealed by successful co-crystallization of the probe/enzyme mutant complex. A refined green fluorescent probe (CDG-OMe) enabled the successful detection of live pathogen in less than ten minutes, even in unprocessed human sputum. This system offers the opportunity for the rapid, accurate detection of very low numbers of Mtb for the clinical diagnosis of tuberculosis in sputum and other specimens. PMID:23000993

  16. Prevalence of β-lactam (blaTEM) and Metronidazole (nim) Resistance Genes in the Oral Cavity of Greek Subjects

    PubMed Central

    Koukos, Georgios; Konstantinidis, Antonios; Tsalikis, Lazaros; Arsenakis, Minas; Slini, Theodora; Sakellari, Dimitra

    2016-01-01

    Objectives: The aim of this study is to investigate the prevalence of blaTEM and nim genes that encode resistance to β-lactams and nitroimidazoles, respectively, in the oral cavity of systemically healthy Greek subjects. Materials and Methodology: After screening 720 potentially eligible subjects, 154 subjects were recruited for the study, including 50 periodontally healthy patients, 52 cases of gingivitis and 52 cases of chronic periodontitis. The clinical parameters were assessed with an automated probe. Various samples were collected from the tongue, first molars and pockets >6mm, and analysed by polymerase chain reaction-amplification of the blaTEM and nim genes, using primers and conditions previously described in the literature. Results: There was a high rate of detection of blaTEM in plaque and tongue samples alike in all periodontal conditions (37% of plaque and 60% of tongue samples, and 71% of participants). The blaTEM gene was detected more frequently in the tongue samples of the periodontally healthy (56%) and chronic periodontitis (62%) groups compared to the plaque samples from the same groups (36% and 29%, respectively; z-test with Bonferroni corrections-tests, P<0.05). The nim gene was not detected in any of the 343 samples analysed. Conclusion: The oral cavity of Greek subjects often harbours blaTEM but not nim genes, and therefore the antimicrobial activity of β-lactams might be compromised. PMID:27099637

  17. The Complex Genetic Context of blaPER-1 Flanked by Miniature Inverted-Repeat Transposable Elements in Acinetobacter johnsonii

    PubMed Central

    Zong, Zhiyong

    2014-01-01

    On a large plasmid of Acinetobacter johnsonii strain XBB1 from hospital sewage, blaPER-1 and ISCR1 were found in a complex Tn402-like integron carrying an arr3-aacA4 cassette array. The integron was truncated by the same 439-bp miniature inverted-repeat transposable element (MITE) at both ends. blaPER-1 and its complex surroundings might have been mobilized by the MITEst into an orf of unknown function, evidenced by the presence of the characteristic 5-bp direct target repeats. The same 439-bp MITEs have also been found flanking class 1 integrons carrying metallo-β-lactamases genes blaIMP-1, blaIMP-5 and blaVIM-2 before but without ISCR1. Although the cassette arrays are different, integrons have always been truncated by the 439-bp MITEs at the exact same locations. The results suggested that MITEs might be able to mobilize class 1 integrons via transposition or homologous recombination and therefore represent a possible common mechanism for mobilizing antimicrobial resistance determinants. PMID:24587208

  18. Rapid point-of-care detection of the tuberculosis pathogen using a BlaC-specific fluorogenic probe

    NASA Astrophysics Data System (ADS)

    Xie, Hexin; Mire, Joseph; Kong, Ying; Chang, Mihee; Hassounah, Hany A.; Thornton, Chris N.; Sacchettini, James C.; Cirillo, Jeffrey D.; Rao, Jianghong

    2012-10-01

    Early diagnosis of tuberculosis can dramatically reduce both its transmission and the associated death rate. The extremely slow growth rate of the causative pathogen, Mycobacterium tuberculosis (Mtb), however, makes this challenging at the point of care, particularly in resource-limited settings. Here we report the use of BlaC (an enzyme naturally expressed/secreted by tubercle bacilli) as a marker and the design of BlaC-specific fluorogenic substrates as probes for Mtb detection. These probes showed an enhancement by 100-200 times in fluorescence emission on BlaC activation and a greater than 1,000-fold selectivity for BlaC over TEM-1 β-lactamase, an important factor in reducing false-positive diagnoses. Insight into the BlaC specificity was revealed by successful co-crystallization of the probe/enzyme mutant complex. A refined green fluorescent probe (CDG-OMe) enabled the successful detection of live pathogen in less than ten minutes, even in unprocessed human sputum. This system offers the opportunity for the rapid, accurate detection of very low numbers of Mtb for the clinical diagnosis of tuberculosis in sputum and other specimens.

  19. Quantifying Nonspecific TEM β-Lactamase (blaTEM) Genes in a Wastewater Stream▿

    PubMed Central

    Lachmayr, Karen L.; Kerkhof, Lee J.; DiRienzo, A. Gregory; Cavanaugh, Colleen M.; Ford, Timothy E.

    2009-01-01

    To control the antibiotic resistance epidemic, it is necessary to understand the distribution of genetic material encoding antibiotic resistance in the environment and how anthropogenic inputs, such as wastewater, affect this distribution. Approximately two-thirds of antibiotics administered to humans are β-lactams, for which the predominant bacterial resistance mechanism is hydrolysis by β-lactamases. Of the β-lactamases, the TEM family is of overriding significance with regard to diversity, prevalence, and distribution. This paper describes the design of DNA probes universal for all known TEM β-lactamase genes and the application of a quantitative PCR assay (also known as Taqman) to quantify these genes in environmental samples. The primer set was used to study whether sewage, both treated and untreated, contributes to the spread of these genes in receiving waters. It was found that while modern sewage treatment technologies reduce the concentrations of these antibiotic resistance genes, the ratio of blaTEM genes to 16S rRNA genes increases with treatment, suggesting that bacteria harboring blaTEM are more likely to survive the treatment process. Thus, β-lactamase genes are being introduced into the environment in significantly higher concentrations than occur naturally, creating reservoirs of increased resistance potential. PMID:18997031

  20. Clonal and horizontal spread of the blaOXA-232 gene among Enterobacteriaceae in a Korean hospital.

    PubMed

    Jeong, Seok Hoon; Lee, Kyu Man; Lee, Jacob; Bae, Il Kwon; Kim, Jae-Seok; Kim, Han-Sung; Song, Wonkeun

    2015-05-01

    All 16 Klebsiella pneumoniae isolates and both Escherichia coli isolates harbored the bla(OXA-232) and bla(CTX-M-15) genes. Furthermore, all 16 K. pneumoniae isolates belonged to a unique pulsed-field gel electrophoresis clone and were assigned to an identical sequence type (ST14). The 2 E. coli isolates were identified as ST131 and ST457. The bla(OXA-232) gene underwent horizontal transfer to E. coli isolates via a conjugative ColE-type plasmid. The introduction of this K. pneumoniae ST14 strain to the Korean hospital was attributed to an index patient who was likely colonized during a prior hospitalization in India. PMID:25702524

  1. Further Spread of blaNDM-5 in Enterobacteriaceae via IncX3 Plasmids in Shanghai, China

    PubMed Central

    Zhang, Fangfang; Xie, Lianyan; Wang, Xiaoli; Han, Lizhong; Guo, Xiaokui; Ni, Yuxing; Qu, Hongping; Sun, Jingyong

    2016-01-01

    One hundred and two carbapenem-resistant Enterobacteriaceae (CRE) strains were isolated in a teaching hospital in Shanghai, China from 2012 to 2015. In a follow-up study, four New Delhi metallo-β-lactamase-5 (NDM-5)-producing strains were identified after screening these CRE strains, including 1 Klebsiella pneumoniae strain (RJ01), 1 Proteus mirabilis strain (RJ02), and 2 Escherichia coli strains (RJ03 and RJ04). All K. pneumoniae and E. coli isolates were resistant to carbapenems, third-generation cephalosporins, and piperacillin-tazobactam, but were susceptible to amikacin. No epidemiological links for either E. coli isolate were found by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). However, MLST revealed a novel sequence type, ST2250, of the K. pneumoniae RJ01 strain. Inc types and sizes of blaNDM-5-carrying plasmids differed among the four isolates, although in P. mirabilis RJ02 and E. coli RJ03, blaNDM-5 was carried by conjugative IncX3 plasmids of nearly the same size (∼40 kb). Investigation of the genetic background of sequences flanking the blaNDM-5 gene showed that all four isolates shared the same genetic content (IS3000-ΔISAba125-IS5-blaNDM-5-ble-trpF-dsbC-IS26-ΔumuD), which was identical to that of the pNDM_MGR194 plasmid circulating in India. This is the first identification of blaNDM-5 in P. mirabilis, which suggests its further spread to Enterobacteriaceae, and indicates that IncX3 plasmids may play an important role in potentiating the spread of blaNDM. PMID:27065982

  2. Molecular typing and genetic environment of the blaKPC gene in Chilean isolates of Klebsiella pneumoniae.

    PubMed

    Barría-Loaiza, Carla; Pincheira, Andrea; Quezada, Mario; Vera, Alejandra; Valenzuela, Pedro; Domínguez, Mariana; Lima, Celia A; Araya, Ingrid; Araya, Pamela; Prat, Soledad; Aguayo, Carolina; Fernández, Jorge; Hormazábal, Juan Carlos; Bello-Toledo, Helia; González-Rocha, Gerardo

    2016-03-01

    The aim of this work was to determine the genetic environment and transferability of blaKPC as well as the pulsotypes of KPC-producing Klebsiella pneumoniae strains isolated from clinical samples in Chilean hospitals. Seventeen strains, principally isolated in Santiago (the capital of Chile) during the years 2012 and 2013, were included. The genetic environment of blaKPC was elucidated by PCR mapping and sequencing. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Curing and conjugation experiments were performed with six strains of different sequence types (STs) and pulsotypes. Thirteen pulsotypes and six STs, mainly belonging to clonal complex 258, were found. In addition, seven strains belonged to a new ST assigned ST1161. The blaKPC sequence indicated that 16 strains had the KPC-2 variant; in only one strain (UC331) an amino acid change (R6P) was detected, corresponding to a new KPC variant designated KPC-24. Molecular characterisation of the blaKPC genetic environment revealed two distinct platforms, namely variant 1a and the Tn4401a isoform, with the first being the most common (11/17 strains). Mating experiments failed to produce transconjugants; however, loss of blaKPC was achieved by plasmid curing in all assayed strains. In conclusion, in Chilean strains of K. pneumoniae, blaKPC is primarily found associated with the variant 1a and is located in non-transferable plasmids. In addition, this study highlights the description of the new ST1161 and the new KPC-24 variant. PMID:27436389

  3. Further Spread of bla NDM-5 in Enterobacteriaceae via IncX3 Plasmids in Shanghai, China.

    PubMed

    Zhang, Fangfang; Xie, Lianyan; Wang, Xiaoli; Han, Lizhong; Guo, Xiaokui; Ni, Yuxing; Qu, Hongping; Sun, Jingyong

    2016-01-01

    One hundred and two carbapenem-resistant Enterobacteriaceae (CRE) strains were isolated in a teaching hospital in Shanghai, China from 2012 to 2015. In a follow-up study, four New Delhi metallo-β-lactamase-5 (NDM-5)-producing strains were identified after screening these CRE strains, including 1 Klebsiella pneumoniae strain (RJ01), 1 Proteus mirabilis strain (RJ02), and 2 Escherichia coli strains (RJ03 and RJ04). All K. pneumoniae and E. coli isolates were resistant to carbapenems, third-generation cephalosporins, and piperacillin-tazobactam, but were susceptible to amikacin. No epidemiological links for either E. coli isolate were found by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). However, MLST revealed a novel sequence type, ST2250, of the K. pneumoniae RJ01 strain. Inc types and sizes of bla NDM-5-carrying plasmids differed among the four isolates, although in P. mirabilis RJ02 and E. coli RJ03, bla NDM-5 was carried by conjugative IncX3 plasmids of nearly the same size (∼40 kb). Investigation of the genetic background of sequences flanking the bla NDM-5 gene showed that all four isolates shared the same genetic content (IS3000-ΔISAba125-IS5-bla NDM-5-ble-trpF-dsbC-IS26-ΔumuD), which was identical to that of the pNDM_MGR194 plasmid circulating in India. This is the first identification of bla NDM-5 in P. mirabilis, which suggests its further spread to Enterobacteriaceae, and indicates that IncX3 plasmids may play an important role in potentiating the spread of bla NDM. PMID:27065982

  4. Detection of New Delhi metallo-β-lactamase (encoded by blaNDM-1) in Acinetobacter schindleri during routine surveillance.

    PubMed

    McGann, Patrick; Milillo, Michael; Clifford, Robert J; Snesrud, Erik; Stevenson, Lindsay; Backlund, Michael G; Viscount, Helen B; Quintero, Reyes; Kwak, Yoon I; Zapor, Michael J; Waterman, Paige E; Lesho, Emil P

    2013-06-01

    A carbapenem-resistant Alcaligenes faecalis strain was isolated from a surveillance swab of a service member injured in Afghanistan. The isolate was positive for bla(NDM) by real-time PCR. Species identification was reevaluated on three identification systems but was inconclusive. Genome sequencing indicated that the closest relative was Acinetobacter schindleri and that bla(NDM-1) was carried on a plasmid that shared >99% identity with one identified in an Acinetobacter lwoffii isolate. The isolate also carried a novel chromosomally encoded class D oxacillinase. PMID:23554204

  5. Increased prevalence of carbapenem resistant Enterobacteriaceae in hospital setting due to cross-species transmission of the bla NDM-1 element and clonal spread of progenitor resistant strains.

    PubMed

    Wang, Xuan; Chen, Gongxiang; Wu, Xiaoyan; Wang, Liangping; Cai, Jiachang; Chan, Edward W; Chen, Sheng; Zhang, Rong

    2015-01-01

    This study investigated the transmission characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains collected from a hospital setting in China, in which consistent emergence of CRE strains were observable during the period of May 2013 to February 2014. Among the 45 CRE isolates tested, 21 (47%) strains were found to harbor the bla NDM-1 element, and the rest of 24 CRE strains were all positive for bla KPC-2. The 21 bla NDM-1-borne strains were found to comprise multiple Enterobacteriaceae species including nine Enterobacter cloacae, three Escherichia coli, three Citrobacter freundii, two Klebsiella pneumoniae, two Klebsiella oxytoca, and two Morganella morganii strains, indicating that cross-species transmission of bla NDM-1 is a common event. Genetic analyses by PFGE and MLST showed that, with the exception of E. coli and E. cloacae, strains belonging to the same species were often genetically unrelated. In addition to bla NDM-1, several CRE strains were also found to harbor the bla KPC-2, bla VIM-1, and bla IMP-4 elements. Conjugations experiments confirmed that the majority of carbapenem resistance determinants were transferable. Taken together, our findings suggest that transmission of mobile resistance elements among members of Enterobacteriaceae and clonal spread of CRE strains may contribute synergistically to a rapid increase in the population of CRE in clinical settings, prompting a need to implement more rigorous infection control measures to arrest such vicious transmission cycle in CRE-prevalent areas. PMID:26136735

  6. Genotypic and Antimicrobial Susceptibility of Carbapenem-resistant Acinetobacter baumannii: Analysis of ISAba Elements and blaOXA-23-like Genes Including a New Variant

    PubMed Central

    Bahador, Abbas; Raoofian, Reza; Pourakbari, Babak; Taheri, Mohammad; Hashemizadeh, Zahra; Hashemi, Farhad B.

    2015-01-01

    Carbapenem-resistant Acinetobacter baumannii (CR-AB) causes serious nosocomial infections, especially in ICU wards of hospitals, worldwide. Expression of blaOXA genes is the chief mechanism of conferring carbapenem resistance among CR-AB. Although some blaOXA genes have been studied among CR-AB isolates from Iran, their blaOXA-23-like genes have not been investigated. We used a multiplex-PCR to detect Ambler class A, B, and D carbapenemases of 85 isolates, and determined that 34 harbored blaOXA-23-like genes. Amplified fragment length polymorphism (AFLP) genotyping, followed by DNA sequencing of blaOXA-23-like amplicons of CR-AB from each AFLP group was used to characterize their blaOXA-23-like genes. We also assessed the antimicrobial susceptibility pattern of CR-AB isolates, and tested whether they harbored insertion sequences ISAba1 and ISAba4. Sequence comparison with reference strain A. baumannii (NCTC12156) revealed five types of mutations in blaOXA-23-like genes; including one novel variant and four mutants that were already reported from China and the USA. All of the blaOXA-23-like genes mutations were associated with increased minimum inhibitory concentrations (MICs) against imipenem. ISAba1 and ISAba4 sequences were detected upstream of blaOXA-23 genes in 19 and 7% of isolates, respectively. The isolation of CR-AB with new blaOXA-23 mutations including some that have been reported from the USA and China highlights CR-AB pervasive distribution, which underscores the importance of concerted national and global efforts to control the spread of CR-AB isolates worldwide. PMID:26617588

  7. Recent Emergence of Escherichia coli with Cephalosporin Resistance Conferred by blaCTX-M on Washington State Dairy Farms

    PubMed Central

    Sischo, William M.; Jones, Lisa P.; Moore, Dale A.; Ahmed, Sara; Short, Diana M.; Besser, Thomas E.

    2015-01-01

    Enterobacteriaceae-associated blaCTX-M genes have become globally widespread within the past 30 years. Among isolates from Washington State cattle, Escherichia coli strains carrying blaCTX-M (CTX-M E. coli strains) were absent from a set of 2008 isolates but present in a set of isolates from 2011. On 30 Washington State dairy farms sampled in 2012, CTX-M E. coli prevalence was significantly higher on eastern than on northwestern Washington farms, on farms with more than 3,000 adult cows, and on farms that recently received new animals. The addition of fresh bedding to calf hutches at least weekly and use of residual fly sprays were associated with lower prevalence of CTX-M E. coli. In Washington State, the occurrence of human pathogens carrying blaCTX-M genes preceded the emergence of blaCTX-M-associated E. coli in cattle, indicating that these resistance determinants and/or their bacterial hosts may have emerged in human populations prior to their dissemination to cattle populations. PMID:25911480

  8. blaCTX-M-I group extended spectrum beta lactamase-producing Salmonella typhi from hospitalized patients in Lagos, Nigeria

    PubMed Central

    Akinyemi, Kabiru O; Iwalokun, Bamidele A; Alafe, Olajide O; Mudashiru, Sulaiman A; Fakorede, Christopher

    2015-01-01

    Purpose The global spread of blaCTX-M-I extended-spectrum beta-lactamase (ESBL)-producing Salmonella spp. remains a major threat to treatment and control. Evidence of emergence and spread of this marker are lacking in Nigeria. This study investigated blaCTX-M-I ESBL production among Salmonella isolates from hospitalized patients. Methods Patients (158 total) made up of two groups were evaluated. Group A was composed of 135 patients with persistent pyrexia and group B was composed of 23 gastroenteritis patients and their stool samples. Samples were cultured, and isolates were identified and were subjected to antibiotic susceptibility testing by standard methods. Isolates were further screened for ESBL production, blaCTX-M-I genes and transferability by double disk synergy test, plasmid extraction, polymerase chain reaction, and conjugation experiment. Results Thirty-five (25.9%) Salmonella isolates were identified from group A, of which 74.3% were S. typhi, 22.9% were S. paratyphi and two (5.7%) were invasive non-typhoidal S. enteritidis. Nine Plasmodium falciparum infections were recorded, four of which were identified as co-infections with typhoidal Salmonella. Only two (8.7%) S. enteritidis samples were obtained from group B (P>0.05). A total of 24 isolates were ESBL-positive, eliciting resistance to five to seven antibiotics, and were multiple-drug resistant. ESBL production due to the blaCTX-M-I gene cluster was detected in eleven (45.8%) Salmonella isolates. Nine (81.8%) of the eleven blaCTX-M-I ESBL producers were S. typhi and two (18.2%) isolates were S. enteritidis. Four of nine S. typhi blaCTX-M-I ESBL-producing strains harbored 23 kb self-transmissible plasmid that was co-transferred with cefotaxime and augmentin resistance to Escherichia coli j53-2 transconjugants. Conclusion This study revealed the emergence of blaCTX-M-I S. typhi as an agent of persistent pyrexia with potential to spread to other Enterobacteriaceae in Lagos, Nigeria. Cautionary

  9. Nested Russian Doll-Like Genetic Mobility Drives Rapid Dissemination of the Carbapenem Resistance Gene blaKPC.

    PubMed

    Sheppard, Anna E; Stoesser, Nicole; Wilson, Daniel J; Sebra, Robert; Kasarskis, Andrew; Anson, Luke W; Giess, Adam; Pankhurst, Louise J; Vaughan, Alison; Grim, Christopher J; Cox, Heather L; Yeh, Anthony J; Sifri, Costi D; Walker, A Sarah; Peto, Tim E; Crook, Derrick W; Mathers, Amy J

    2016-06-01

    The recent widespread emergence of carbapenem resistance in Enterobacteriaceae is a major public health concern, as carbapenems are a therapy of last resort against this family of common bacterial pathogens. Resistance genes can mobilize via various mechanisms, including conjugation and transposition; however, the importance of this mobility in short-term evolution, such as within nosocomial outbreaks, is unknown. Using a combination of short- and long-read whole-genome sequencing of 281 blaKPC-positive Enterobacteriaceae isolates from a single hospital over 5 years, we demonstrate rapid dissemination of this carbapenem resistance gene to multiple species, strains, and plasmids. Mobility of blaKPC occurs at multiple nested genetic levels, with transmission of blaKPC strains between individuals, frequent transfer of blaKPC plasmids between strains/species, and frequent transposition of blaKPC transposon Tn4401 between plasmids. We also identify a common insertion site for Tn4401 within various Tn2-like elements, suggesting that homologous recombination between Tn2-like elements has enhanced the spread of Tn4401 between different plasmid vectors. Furthermore, while short-read sequencing has known limitations for plasmid assembly, various studies have attempted to overcome this by the use of reference-based methods. We also demonstrate that, as a consequence of the genetic mobility observed in this study, plasmid structures can be extremely dynamic, and therefore these reference-based methods, as well as traditional partial typing methods, can produce very misleading conclusions. Overall, our findings demonstrate that nonclonal resistance gene dissemination can be extremely rapid, presenting significant challenges for public health surveillance and achieving effective control of antibiotic resistance. PMID:27067320

  10. Combinatorial active-site variants confer sustained clavulanate resistance in BlaC β-lactamase from Mycobacterium tuberculosis

    PubMed Central

    Egesborg, Philippe; Carlettini, Hélène; Volpato, Jordan P; Doucet, Nicolas

    2015-01-01

    Bacterial resistance to β-lactam antibiotics is a global issue threatening the success of infectious disease treatments worldwide. Mycobacterium tuberculosis has been particularly resilient to β-lactam treatment, primarily due to the chromosomally encoded BlaC β-lactamase, a broad-spectrum hydrolase that renders ineffective the vast majority of relevant β-lactam compounds currently in use. Recent laboratory and clinical studies have nevertheless shown that specific β-lactam–BlaC inhibitor combinations can be used to inhibit the growth of extensively drug-resistant strains of M. tuberculosis, effectively offering new tools for combined treatment regimens against resistant strains. In the present work, we performed combinatorial active-site replacements in BlaC to demonstrate that specific inhibitor-resistant (IRT) substitutions at positions 69, 130, 220, and/or 234 can act synergistically to yield active-site variants with several thousand fold greater in vitro resistance to clavulanate, the most common clinical β-lactamase inhibitor. While most single and double variants remain sensitive to clavulanate, double mutants R220S-K234R and S130G-K234R are substantially less affected by time-dependent clavulanate inactivation, showing residual β-lactam hydrolytic activities of 46% and 83% after 24 h incubation with a clinically relevant inhibitor concentration (5 μg/ml, 25 µM). These results demonstrate that active-site alterations in BlaC yield resistant variants that remain active and stable over prolonged bacterial generation times compatible with mycobacterial proliferation. These results also emphasize the formidable adaptive potential of inhibitor-resistant substitutions in β-lactamases, potentially casting a shadow on specific β-lactam–BlaC inhibitor combination treatments against M. tuberculosis. PMID:25492589

  11. Nested Russian Doll-Like Genetic Mobility Drives Rapid Dissemination of the Carbapenem Resistance Gene blaKPC

    PubMed Central

    Wilson, Daniel J.; Sebra, Robert; Kasarskis, Andrew; Anson, Luke W.; Giess, Adam; Pankhurst, Louise J.; Vaughan, Alison; Grim, Christopher J.; Cox, Heather L.; Yeh, Anthony J.; Sifri, Costi D.; Walker, A. Sarah; Peto, Tim E.; Crook, Derrick W.

    2016-01-01

    The recent widespread emergence of carbapenem resistance in Enterobacteriaceae is a major public health concern, as carbapenems are a therapy of last resort against this family of common bacterial pathogens. Resistance genes can mobilize via various mechanisms, including conjugation and transposition; however, the importance of this mobility in short-term evolution, such as within nosocomial outbreaks, is unknown. Using a combination of short- and long-read whole-genome sequencing of 281 blaKPC-positive Enterobacteriaceae isolates from a single hospital over 5 years, we demonstrate rapid dissemination of this carbapenem resistance gene to multiple species, strains, and plasmids. Mobility of blaKPC occurs at multiple nested genetic levels, with transmission of blaKPC strains between individuals, frequent transfer of blaKPC plasmids between strains/species, and frequent transposition of blaKPC transposon Tn4401 between plasmids. We also identify a common insertion site for Tn4401 within various Tn2-like elements, suggesting that homologous recombination between Tn2-like elements has enhanced the spread of Tn4401 between different plasmid vectors. Furthermore, while short-read sequencing has known limitations for plasmid assembly, various studies have attempted to overcome this by the use of reference-based methods. We also demonstrate that, as a consequence of the genetic mobility observed in this study, plasmid structures can be extremely dynamic, and therefore these reference-based methods, as well as traditional partial typing methods, can produce very misleading conclusions. Overall, our findings demonstrate that nonclonal resistance gene dissemination can be extremely rapid, presenting significant challenges for public health surveillance and achieving effective control of antibiotic resistance. PMID:27067320

  12. Detection of chromosomal blaCTX-M-15 in Escherichia coli O25b-B2-ST131 isolates from the Kinki region of Japan.

    PubMed

    Hirai, Itaru; Fukui, Naoki; Taguchi, Masumi; Yamauchi, Kou; Nakamura, Tatsuya; Okano, Sho; Yamamoto, Yoshimasa

    2013-12-01

    Escherichia coli O25b-B2-ST131 isolates harbouring bla(CTX-M-15) are distributed worldwide. The bla(CTX-M-15) transposition unit has often been found on plasmids and the genetic contexts have been examined; however, less is known about the frequency and contexts of the bla(CTX-M-15) transposition unit on the chromosome. This study was performed to determine the chromosomal location of the bla(CTX-M-15) transposition unit and to analyse the molecular structure of the region surrounding the bla(CTX-M-15) transposition unit in E. coli O25b-B2-ST131 isolates. Twenty-two E. coli O25b-B2-ST131 strains harbouring bla(CTX-M-15) that had been isolated from university hospital patients and nursing home residents in the Kinki region of Japan were examined. Inverse PCR (iPCR) targeting bla(CTX-M-15) was performed to classify the molecular structure of the region surrounding the bla(CTX-M-15) transposition unit. The isolates were classified into nine types (types A-I) considering the iPCR results; type A was the most prevalent type (13/22 isolates). Sequences of the iPCR-amplified DNA fragments showed that the bla(CTX-M-15) transposition unit consisted of ISEcp1, bla(CTX-M-15) and orf477Δ. A homology search of the obtained sequences showed that the bla(CTX-M-15) transposition unit was inserted into different chromosomal regions in eight of the nine classified types. Although 21 of the 22 E. coli isolates possessed chromosomally located bla(CTX-M-15) transposition units, clonal spread was not evident on pulsed-field gel electrophoresis (PFGE) analysis. Taken together, these data indicate that certain E. coli O25b-B2-ST131 strains harbouring chromosomal bla(CTX-M-15) have emerged and spread in the Kinki region of Japan. PMID:24091130

  13. First Description of the Extended Spectrum-Beta-Lactamase Gene blaCTX-M-109 in Salmonella Grumpensis Strains Isolated from Neonatal Nosocomial Infections in Dakar, Senegal

    PubMed Central

    Seck, Abdoulaye; Dia, Mouhamadou Lamine; Timbiné, Lassina Gadi; Niang, Aïssatou Ameth; Ndiaye, El Hadji Momar; Sonko, Mouhamadou Abdoulaye; Wane, Abdoul Aziz; Bercion, Raymond; Ndiaye, Ousmane; Cissé, Moussa Fafa; Gassama-Sow, Amy

    2016-01-01

    Nosocomial infections are very common in African hospitals, particularly in neonatal units. These infections are most often caused by bacteria such as Escherichia coli, Klebsiella spp and Staphylococcus spp. Salmonella strains are rarely involved in nosocomial infections. Here, we report the first description of S. Grumpensis in neonatal infections in Senegal. Seventeen Salmonella strains were isolated from hospitalized infants’ stool samples. The following resistance phenotype was described in strains: AMXRTICRCFR FOXRCFXRCTXRCAZRIMPSATMRNARNORRCIPRTMRGMRTERSXTR. All isolates were susceptible to imipenem, 15 out of 17 produced an extended spectrum ß-lactamase (ESBL). blaOXA-1, blaSHV-1, blaTEM-1, blaCTX-M1 genes were detected in strains 8, 13, 5 and 8, respectively. blaCTX-M1 sequencing revealed the presence of blaCTX-M-109. Thirteen of the 17 Salmonella Grumpensis strains were analyzed by PFGE. These 13 isolates belonged to a single pulsotype and were genotypically identical. This is the first report of neonatal S. Grumpensis infections in Senegal, and the first report of blaCTX-M-109 in the genus Salmonella. PMID:27355480

  14. First Description of the Extended Spectrum-Beta-Lactamase Gene blaCTX-M-109 in Salmonella Grumpensis Strains Isolated from Neonatal Nosocomial Infections in Dakar, Senegal.

    PubMed

    Diop, Amadou; Sambe-Ba, Bissoume; Seck, Abdoulaye; Dia, Mouhamadou Lamine; Timbiné, Lassina Gadi; Niang, Aïssatou Ameth; Ndiaye, El Hadji Momar; Sonko, Mouhamadou Abdoulaye; Wane, Abdoul Aziz; Bercion, Raymond; Ndiaye, Ousmane; Cissé, Moussa Fafa; Gassama-Sow, Amy

    2016-01-01

    Nosocomial infections are very common in African hospitals, particularly in neonatal units. These infections are most often caused by bacteria such as Escherichia coli, Klebsiella spp and Staphylococcus spp. Salmonella strains are rarely involved in nosocomial infections. Here, we report the first description of S. Grumpensis in neonatal infections in Senegal. Seventeen Salmonella strains were isolated from hospitalized infants' stool samples. The following resistance phenotype was described in strains: AMXRTICRCFR FOXRCFXRCTXRCAZRIMPSATMRNARNORRCIPRTMRGMRTERSXTR. All isolates were susceptible to imipenem, 15 out of 17 produced an extended spectrum ß-lactamase (ESBL). blaOXA-1, blaSHV-1, blaTEM-1, blaCTX-M1 genes were detected in strains 8, 13, 5 and 8, respectively. blaCTX-M1 sequencing revealed the presence of blaCTX-M-109. Thirteen of the 17 Salmonella Grumpensis strains were analyzed by PFGE. These 13 isolates belonged to a single pulsotype and were genotypically identical. This is the first report of neonatal S. Grumpensis infections in Senegal, and the first report of blaCTX-M-109 in the genus Salmonella. PMID:27355480

  15. Genetic Characterization of ST195 and ST365 Carbapenem-Resistant Acinetobacter baumannii Harboring blaOXA-23 in Guangzhou, China.

    PubMed

    Zhou, Yong; Wu, Xinwei; Zhang, Xinqiang; Hu, Yushan; Yang, Xia; Yang, Zhicong; Wang, Ming

    2015-08-01

    We investigated the distribution of resistance genes and the clonal relationships among carbapenem-resistant Acinetobacter baumannii isolates from the intensive care unit wards of two hospitals in Guangzhou, China. From 2012 to 2013, 57 A. baumannii isolates were obtained from blood cultures from two hospitals in Guangzhou. The antibiotic resistance profiles were determined by using the Vitek2 system and Etest strips. PCR was used to detect the genes encoding OXA-type carbapenemases and metallo-β-lactamases and the presence of ISAba1 upstream of the bla(OXA-51-like) gene and the bla(OXA-23-like) gene. Multilocus sequence typing (MLST) and sequence-based typing of bla(OXA-51-like) genes (SBT-bla(OXA-51-like )genes) were performed to analyze the genetic relationship of the isolates. Among the 57 isolates, 46 were carbapenem-resistant A. baumannii (CRAB) isolates. The bla(OXA-51-like) gene was identified in all 57 isolates, while the bla(OXA-23-like) gene was present in all 46 CRAB isolates. The MLST analysis grouped the A. baumannii isolates into five existing sequence types (STs) and five new STs. Fifty-two isolates belonged to the worldwide spread of clonal complex 92 (CC92), among which ST195 and ST365 were the most common STs. The MLST data and SBT-bla(OXA-51-like) genes showed that all isolates harboring the major bla(OXA-51-like) alleles, such as bla(OXA-66), belonged to CC92. PMID:25602500

  16. First Report of blaIMP-14 on a Plasmid Harboring Multiple Drug Resistance Genes in Escherichia coli Sequence Type 131.

    PubMed

    Stoesser, Nicole; Sheppard, Anna E; Peirano, Gisele; Sebra, Robert P; Lynch, Tarah; Anson, Luke W; Kasarskis, Andrew; Motyl, Mary R; Crook, Derrick W; Pitout, Johann D

    2016-08-01

    The blaIMP-14 carbapenem resistance gene has largely previously been observed in Pseudomonas aeruginosa and Acinetobacter spp. As part of global surveillance and sequencing of carbapenem-resistant Escherichia coli, we identified a sequence type 131 strain harboring blaIMP-14 within a class 1 integron, itself nested within an ∼54-kb multidrug resistance region on an epidemic IncA/C2 plasmid. The emergence of blaIMP-14 in this context in the ST131 lineage is of potential clinical concern. PMID:27246777

  17. First Report of blaIMP-14 on a Plasmid Harboring Multiple Drug Resistance Genes in Escherichia coli Sequence Type 131

    PubMed Central

    Sheppard, Anna E.; Peirano, Gisele; Sebra, Robert P.; Lynch, Tarah; Anson, Luke W.; Kasarskis, Andrew; Motyl, Mary R.; Crook, Derrick W.; Pitout, Johann D.

    2016-01-01

    The blaIMP-14 carbapenem resistance gene has largely previously been observed in Pseudomonas aeruginosa and Acinetobacter spp. As part of global surveillance and sequencing of carbapenem-resistant Escherichia coli, we identified a sequence type 131 strain harboring blaIMP-14 within a class 1 integron, itself nested within an ∼54-kb multidrug resistance region on an epidemic IncA/C2 plasmid. The emergence of blaIMP-14 in this context in the ST131 lineage is of potential clinical concern. PMID:27246777

  18. Molecular characterisation of acquired and overproduced chromosomal blaAmpC in Escherichia coli clinical isolates.

    PubMed

    Alonso, Noemí; Miró, Elisenda; Pascual, Vanesa; Rivera, Alba; Simó, Maria; Garcia, Maria Consol; Xercavins, Mariona; Morera, Maria Antonia; Espejo, Elena; Gurguí, Mercè; Pérez, Josefa; Rodríguez-Carballeira, Mònica; Garau, Javier; Calbo, Esther; Navarro, Ferran; Mirelis, Beatriz; Coll, Pere

    2016-01-01

    Escherichia coli recovered from three hospitals in Barcelona (Spain) were studied to determine the prevalence of isolates with acquired AmpC (ac-AmpC) and/or overproduced chromosomal AmpC (c-AmpC). Mechanisms involved in blac-AmpC overexpression, blaac-AmpC and the plasmids associated with their distribution as well as the prevalence of plasmid-mediated quinolone resistance (PMQR) in AmpC-producing isolates were also determined. Isolates were selected according to their resistance phenotype. blaac-AmpC, alterations in the blac-AmpC promoter/attenuator, and PMQR genes [qnrA, qnrB, qnrS, aac(6')-Ib-cr and qepA] were characterised by PCR and sequencing. blac-AmpC expression was determined by qRT-PCR. Population structure analysis was performed using PFGE, MLST and phylogenetic group PCR. Plasmids carrying blaac-AmpC were characterised by PCR-based replicon typing and S1-PFGE. IncI1 and IncF plasmids were also analysed by plasmid MLST and replicon sequence typing, respectively. Among 21563 E. coli isolates, 240 (1.1%) overproduced AmpC β-lactamases, including 180 (75.0%) harbouring ac-AmpC (132 CMY-2 variants and 48 DHA-1) and 60 (25.0%) c-AmpC enzymes. Three mutation profiles in the blac-AmpC promoter/attenuator were associated with a 72.5-, 19.9- and 5.8-fold increased expression, respectively. Moreover, 63.3% of ac-AmpC and 43.3% of c-AmpC isolates belonged to B2, D, E or F phylogenetic groups. PMQR was found in 31% of ac-AmpC isolates [38 qnrB4, 8 aac(6')-Ib-cr, 6 qnrS1 and 3 qnrB19] and in 10% of c-AmpC isolates [5 aac(6')-Ib-cr and 1 qnrS1]. IncI1-ST12 and IncF were associated with blaCMY-2 and blaDHA-1, respectively. These results suggest that ac-AmpC β-lactamases were the main mechanism of AmpC production. Isolates and plasmids both showed high genetic diversity. PMID:26607336

  19. High prevalence of blaOXA-23 in Acinetobacter spp. and detection of blaNDM-1 in A. soli in Cuba: report from National Surveillance Program (2010–2012)

    PubMed Central

    Quiñones, D.; Carvajal, I.; Perez, Y.; Hart, M.; Perez, J.; Garcia, S.; Salazar, D.; Ghosh, S.; Kawaguchiya, M.; Aung, M.S.; Kobayashi, N.

    2015-01-01

    As a first national surveillance of Acinetobacter in Cuba, a total of 500 Acinetobacter spp. isolates recovered from 30 hospitals between 2010 and 2012 were studied. Acinetobacter baumannii–calcoaceticus complex accounted for 96.4% of all the Acinetobacter isolates, while other species were detected at low frequency (A. junii 1.6%, A. lwoffii 1%, A. haemolyticus 0.8%, A. soli 0.2%). Resistance rates of isolates were 34–61% to third-generation cephalosporins, 49–50% to β-lactams/inhibitor combinations, 42–47% to aminoglycosides, 42–44% to carbapenems and 55% to ciprofloxacin. However, resistance rates to colistin, doxycycline, tetracycline and rifampin were less than 5%. Among carbapenem-resistant isolates, 75% harboured different blaOXA genes (OXA-23, 73%; OXA-24, 18%; OXA-58, 3%). The blaNDM-1 gene was identified in an A. soli strain, of which the species was confirmed by sequence analysis of 16S rRNA gene, rpoB, rpoB–rpoC and rpoL–rpoB intergenic spacer regions and gyrB. The sequences of blaNDM-1 and its surrounding genes were identical to those reported for plasmids of A. baumannii and A. lwoffi strains. This is the first report of blaNDM-1 in A. soli, together with a high prevalence of OXA-23 carbapenemase for carbapenem resistance in Acinetobacter spp. in Cuba. PMID:26236494

  20. Diverse Genetic Array of blaCTXM-15 in Escherichia coli: A Single-Center Study from India.

    PubMed

    Maurya, Anand Prakash; Mishra, Shweta; Talukdar, Anupam Das; Dhar Chanda, Debadatta; Chakravarty, Atanu; Bhattacharjee, Amitabha

    2016-01-01

    CTX-M-15 is a chief contributor for expanded-spectrum cephalosporin and monobactam resistance in India, complicating treatment options. In this study, we have investigated genetic context of CTX-M-15 in Escherichia coli and their transmission dynamics in a tertiary referral hospital of India. A total of 198 isolates were collected, of which 66 were harboring blaCTXM-15. Among them, 14 isolates were carrying a single CTX-M-15 gene and 52 were harboring multiple extended-spectrum β-lactamase genes along with blaCTX-M-15. The resistance gene was flanked by tnpA, ISEcp1, IS26, and ORF477 in 10 different arrangements. The resistance determinant was horizontally transferable through F, W, I1, and P Inc types of plasmids. Restriction mapping of plasmids showed a variable band pattern even within the same Inc types. Minimum inhibitory concentration was found above the breakpoint level against expanded-spectrum cephalosporins and monobactam while susceptible against carbapenems. blaCTX-M-15 was highly stable and sustained in the cell after 115 serial passages. In pulse-field gel electrophoresis, eight pulsotypes of E. coli were found to be responsible for the spread of blaCTX-M-15 in the tertiary referral center. We conclude that the presence of CTX-M-15 in the heterogeneous group of E. coli is highly alarming in terms of infection control and it may require regular monitoring, so as to formulate appropriate antibiotic policy to stop the spread of this resistance determinant. PMID:26317445

  1. Association between β-Lactamase-Encoding blaOXA-51 Variants and DiversiLab Rep-PCR-Based Typing of Acinetobacter baumannii Isolates

    PubMed Central

    Zander, Esther; Nemec, Alexandr; Seifert, Harald

    2012-01-01

    This study investigated the correlation between blaOXA-51 variants and Acinetobacter baumannii worldwide clonal lineages 1 to 8 (WW1 to -8). The blaOXA-51-like genes of 102 A. baumannii isolates were sequenced. Using DiversiLab repetitive-sequence-based PCR (rep-PCR) typing, 92 of these isolates had previously been assigned to WW1 to -8 and 10 were unclustered. Clustering of DNA sequences was performed using the neighbor-joining method and the Jukes-Cantor phylogenetic correction. blaOXA-51 variants were in good correlation with DiversiLab-defined clonal lineages. Sequence-based typing of blaOXA-51 variants has the potential to be applied for epidemiologic characterization of A. baumannii and to identify worldwide clonal lineages 1 to 8. PMID:22422849

  2. The effect of BLA GABA(A) receptors in anxiolytic-like effect and aversive memory deficit induced by ACPA

    PubMed Central

    Kangarlu-Haghighi, Katayoon; Oryan, Shahrbanoo; Nasehi, Mohammad; Zarrindast, Mohammad-Reza

    2015-01-01

    The roles of GABAergic receptors of the Basolateral amygdala (BLA) in the cannabinoid CB1 receptor agonist (arachydonilcyclopropylamide; ACPA)-induced anxiolytic-like effect and aversive memory deficit in adult male mice were examined in elevated plus-maze task. Results showed that pre-test intra-peritoneal injection of ACPA induced anxiolytic-like effect (at dose of 0.05 mg/kg) and aversive memory deficit (at doses of 0.025 and 0.05 mg/kg). The results revealed that Pre-test intra-BLA infusion of muscimol (GABAA receptor agonist; at doses of 0.1 and 0.2 µg/mouse) or bicuculline (GABAA receptor antagonist; at all doses) impaired and did not alter aversive memory, respectively. All previous GABA agents did not have any effects on anxiety-like behaviors. Interestingly, pretreatment with a sub-threshold dose of muscimol (0.025 µg/mouse) and bicuculline (0.025 µg/mouse) did not alter anxiolytic-like behaviors induced by ACPA, while both drugs restored ACPA-induced amnesia. Moreover, muscimol or bicuculline increased and decreased ACPA-induced locomotor activity, respectively. Finally the data may indicate that BLA GABAA receptors have critical and different roles in anxiolytic-like effect, aversive memory deficit and locomotor activity induced by ACPA. PMID:26648818

  3. Molecular Evolution of a Klebsiella pneumoniae ST278 Isolate Harboring blaNDM-7 and Involved in Nosocomial Transmission.

    PubMed

    Lynch, Tarah; Chen, Liang; Peirano, Gisele; Gregson, Dan B; Church, Deirdre L; Conly, John; Kreiswirth, Barry N; Pitout, Johann D

    2016-09-01

    During 2013, ST278 Klebsiella pneumoniae with blaNDM-7 was isolated from the urine (KpN01) and rectum (KpN02) of a patient in Calgary, Canada. The same strain (KpN04) was subsequently isolated from another patient in the same unit. Interestingly, a carbapenem-susceptible K. pneumoniae ST278 (KpN06) was obtained 1 month later from the blood of the second patient. Next-generation sequencing (NGS) revealed that the loss of carbapenem-resistance in KpN06 was due to a 5-kb deletion on the blaNDM-7-harboring IncX3 plasmid. In addition, an IncFIB plasmid in KpN06 had a 27-kb deletion that removed genes encoding for heavy metal resistance. Phylogenetic analysis showed that the K. pneumoniae ST278 from patient 2 was likely a descendant of KpN02 and that KpN06 was a close progenitor of an environmental ST278. It is unclear whether KpN06 lost the blaNDM-7 gene in vivo. This study detailed the remarkable plasticity and speed of evolutionary changes in multidrug-resistant K. pneumoniae, demonstrating the highly recombinant nature of this species. It also highlights the ability of NGS to clarify molecular microevolutionary events within antibiotic-resistant organisms. PMID:27284091

  4. Cloning of cockroach allergen, Bla g 4, identifies ligand binding proteins (or calycins) as a cause of IgE antibody responses.

    PubMed

    Arruda, L K; Vailes, L D; Hayden, M L; Benjamin, D C; Chapman, M D

    1995-12-29

    An allergen cloned from a Blattella germanica (German cockroach) cDNA library, encoded a 182-amino acid protein of 20,904 Da. This protein, designated B. germanica allergen 4 (Bla g 4), was expressed as a glutathione S-transferase fusion protein in Escherichia coli and purified by affinity chromatography and high-performance liquid chromatography. The prevalence of serum IgE antibody to recombinant Bla g 4 in 73 cockroach allergic patients with asthma ranged from 40% (antigen binding radioimmunoassay) to 60% (plaque immunoassay). Cockroach allergic patients gave positive intradermal skin tests to recombinant Bla g 4 at concentrations of 10(-3)-10(-5) micrograms/ml, whereas non-allergic controls, or cockroach allergic patients with no detectable serum IgE antibody to Bla g 4, gave negative skin tests to 1 microgram/ml. Polymerase chain reaction and Southern analysis identified a 523-base pair DNA encoding Bla g 4 in both B. germanica and Periplaneta americana (American cockroach). However, Northern analysis showed that mRNA encoding Bla g 4 was transcribed in B. germanica but not in P. americana, suggesting that allergen expression was species specific. Sequence similarity searches showed that Bla g 4 was a ligand binding protein or calycin and unexpectedly revealed that this family contained several important allergens: beta-lactoglobulin, from cow milk, and rat and mouse urinary proteins. Although the overall sequence homology between these proteins was low (approximately 20%), macromolecular modeling techniques were used to generate two models of the tertiary structure of Bla g 4, based on comparisons with the x-ray crystal coordinates of bilin binding protein and rodent urinary proteins. The results show that members of the calycin protein family can cause IgE antibody responses by inhalation or ingestion and are associated with asthma and food hypersensitivity. PMID:8537384

  5. Characterization of the genetic environment of blaESBL genes, integrons and toxin-antitoxin systems identified on large transferrable plasmids in multi-drug resistant Escherichia coli

    PubMed Central

    Wang, Juan; Stephan, Roger; Zurfluh, Katrin; Hächler, Herbert; Fanning, Séamus

    2015-01-01

    Objectives: Previously 14 conjugative plasmids from multi-drug resistant (MDR) Escherichia coli from healthy humans and food-producing animals in Switzerland were sequenced. The aim of this study was to extend the genetic characterization of these plasmids with a focus on blaESBL genes including blaCTX-M-1 and blaTEM, class 1 integrons and toxin-antitoxin (TA) systems contained therein. Methods: The nucleotide sequences and subsequent annotation therein of 14 conjugative plasmids were previously determined from their corresponding transconjugants. The TA loci were confirmed by RASTA-Bacteria. Results: Eight of the conjugative plasmids identified were found to encode genes expressing ESBLs. Structural heterogeneity was noted in the regions flanking both the blaCTX-M-1 and blaTEM genes. The blaCTX-M-1 genes were associated with the common insertion sequences ISEcp1 and IS26, and uniquely with an IS5 element in one case; while blaTEM genes were found to be associated with IS26 and Tn2. A new blaTEM-210 gene was identified. Seven class 1 integrons were also identified and assigned into 3 groups, denoted as In54, In369 and In501. Sixteen TA loci belonging to 4 of the TA gene families (relBE, vapBC, ccd and mazEF) were identified on 11 of these plasmids. Conclusions: Comparative sequence analysis of these plasmids provided data on the structures likely to contribute to sequence diversity associated with these accessory genes, including IS26, ISEcp1 and Tn2. All of them contribute to the dissemination of the corresponding resistance genes located on the different plasmids. There appears to be no association between β-lactam encoding genes and TA systems. PMID:25610429

  6. β-Lactamases Encoded by blaCTX-M Group I Genes as Determinants of Resistance of Esbl-Positive Enterobacteriaceae in European Soldiers in Tropical Mali

    PubMed Central

    Hagen, Ralf Matthias; Hinz, Rebecca; Frickmann, Hagen

    2015-01-01

    ESBL (extended-spectrum-β-lactamase)-positive Enterobacteriaceae, which colonized European soldiers in tropical Western African Mali, were subjected to a molecular assessment of their resistance determinants. By doing so, a better insight into the locally endemic pattern of ESBL-associated β-lactamase genes was aspired. From a previous study on diarrhea in European soldiers on deployment in tropical Mali, 15 ESBL-positive Escherichia coli with demonstrated high clonal diversity and one positive Klebsiella pneumoniae were assessed. Polymerase chain reactions (PCRs) for blaTEM and blaSHV β-lactamase genes with subsequent sequencing for the discrimination of ESBL- and non-ESBL variants were performed, followed by four group-specific PCRs for blaCTX-M genes. Non-ESBL-associated blaTEM-1 was identified in six out of 15 (40%) E. coli strains, while 100% of the assessed strains were positive for group I blaCTX-M. Considering the known clonal diversity of the assessed strains, the striking restriction to one group of blaCTX-M genes accounting for the ESBL phenotypes of the isolates suggests little genetic exchange in the local setting. Under such circumstances of restricted numbers of locally endemic target genes, PCR-based screening approaches for ESBL colonization might be promising. PMID:26716016

  7. blaCTX-M-15 carried by IncF-type plasmids is the dominant ESBL gene in Escherichia coli and Klebsiella pneumoniae at a hospital in Ghana.

    PubMed

    Agyekum, Alex; Fajardo-Lubián, Alicia; Ansong, Daniel; Partridge, Sally R; Agbenyega, Tsiri; Iredell, Jonathan R

    2016-04-01

    Escherichia coli and Klebsiella pneumoniae producing extended-spectrum β-lactamases (ESBLs) are among the most multidrug-resistant pathogens in hospitals and are spreading worldwide. Horizontal gene transfer and spread of high-risk clones are involved in ESBL dissemination. Investigation of the resistance phenotypes of 101 consecutive clinical E. coli (n=58) and K. pneumoniae (n=43) isolated at the Komfo Anokye Teaching Hospital in Ghana over 3months revealed 63 (62%) with an ESBL phenotype. All 63 had a blaCTX-M gene, and sequence analysis showed that 62 of these were blaCTX-M-15. blaCTX-M-15 was linked to ISEcp1 and orf477Δ in all isolates, and most isolates also carried blaTEM, aac(3)-II, aacA4cr, and/or blaOXA-30 genes on IncF plasmids. XbaI/pulsed-field electrophoresis showed heterogeneity among isolates of both species, suggesting that blaCTX-M-15 dissemination is caused by horizontal gene transfer rather than clonal spread of these species in Ghana. PMID:26830052

  8. Exploring the potential reservoirs of non specific TEM beta lactamase (blaTEM) gene in the Indo-Gangetic region: A risk assessment approach to predict health hazards.

    PubMed

    Singh, Gulshan; Vajpayee, Poornima; Rani, Neetika; Amoah, Isaac Dennis; Stenström, Thor Axel; Shanker, Rishi

    2016-08-15

    The emergence of antimicrobial resistant bacteria is an important public health and environmental contamination issue. Antimicrobials of β-lactam group accounts for approximately two thirds, by weight, of all antimicrobials administered to humans due to high clinical efficacy and low toxicity. This study explores β-lactam resistance determinant gene (blaTEM) as emerging contaminant in Indo-Gangetic region using qPCR in molecular beacon format. Quantitative Microbial Risk Assessment (QMRA) approach was adopted to predict risk to human health associated with consumption/exposure of surface water, potable water and street foods contaminated with bacteria having blaTEM gene. It was observed that surface water and sediments of the river Ganga and Gomti showed high numbers of blaTEM gene copies and varied significantly (p<0.05) among the sampling locations. The potable water collected from drinking water facility and clinical settings exhibit significant number of blaTEM gene copies (13±0.44-10200±316 gene copies/100mL). It was observed that E.crassipes among aquatic flora encountered in both the rivers had high load of blaTEM gene copies. The information on prevalence of environmental reservoirs of blaTEM gene containing bacteria in Indo-Gangetic region and risk associated will be useful for formulating strategies to protect public from menace of clinical risks linked with antimicrobial resistant bacteria. PMID:27111425

  9. Pyrosequencing Using the Single-Nucleotide Polymorphism Protocol for Rapid Determination of TEM- and SHV-Type Extended-Spectrum β-Lactamases in Clinical Isolates and Identification of the Novel β-Lactamase Genes blaSHV-48, blaSHV-105, and blaTEM-155▿

    PubMed Central

    Jones, C. Hal; Ruzin, Alexey; Tuckman, Margareta; Visalli, Melissa A.; Petersen, Peter J.; Bradford, Patricia A.

    2009-01-01

    TEM- and SHV-type extended-spectrum β-lactamases (ESBLs) are the most common ESBLs found in the United States and are prevalent throughout the world. Amino acid substitutions at a number of positions in TEM-1 lead to the ESBL phenotype, although substitutions at residues 104 (E to K), 164 (R to S or H), 238 (G to S), and 240 (E to K) appear to be particularly important in modifying the spectrum of activity of the enzyme. The SHV-1-derived ESBLs are a less diverse collection of enzymes; however, the majority of amino acid substitutions resulting in an ESBL mirror those seen in the TEM-1-derived enzymes. Pyrosequencing by use of the single-nucleotide polymorphism (SNP) protocol was applied to provide sequence data at positions critical for the ESBL phenotype spanning the blaTEM and blaSHV genes. Three novel β-lactamases are described: the ESBLs TEM-155 (Q39K, R164S, E240K) and SHV-105 (I8F, R43S, G156D, G238S, E240K) and a non-ESBL, SHV-48 (V119I). The ceftazidime, ceftriaxone, and aztreonam MICs for an Escherichia coli isolate expressing blaSHV-105 were >128, 128, and >128 μg/ml, respectively. Likewise, the ceftazidime, ceftriaxone, and aztreonam MICs for an E. coli isolate expressing blaTEM-155 were >128, 64, and > 128 μg/ml, respectively. Pyrosequence analysis determined the true identity of the β-lactamase on plasmid R1010 to be SHV-11 rather than SHV-1, as previously reported. Pyrosequencing is a real-time sequencing-by-synthesis approach that was applied to SNP detection for TEM- and SHV-type ESBL identification and represents a robust tool for rapid sequence determination that may have a place in the clinical setting. PMID:19075050

  10. Impact of blaNDM-1 on fitness and pathogenicity of Escherichia coli and Klebsiella pneumoniae.

    PubMed

    Göttig, Stephan; Riedel-Christ, Sara; Saleh, Ahmad; Kempf, Volkhard A J; Hamprecht, Axel

    2016-06-01

    The objective of this study was to determine whether acquisition of New Delhi metallo-β-lactamase-1 (NDM-1) has an impact on the fitness and virulence of Escherichia coli and Klebsiella pneumoniae. Growth kinetics and the cost of fitness of NDM-1 plasmid carriage were assessed in isogenic E. coli J53 and K. pneumoniae PRZ in vitro by pairwise competition assays. The pathogenicity of NDM-1-expressing E. coli and K. pneumoniae strains and their isogenic controls was analysed in vivo using a Galleria mellonella infection model. The cytotoxicity of NDM-1 was assessed in A549 human lung epithelial cells using the lactate dehydrogenase (LDH) assay. No differences in growth kinetics were recorded between NDM-1-expressing strains and controls (P = 0.92). A reduction in fitness of NDM-1-carrying strains was observed both for E. coli J53 and K. pneumoniae PRZ [selection rate constant (s) = -1.27 ± 0.27 for E. coli J53 and -0.19 ± 0.14 for K. pneumoniae PRZ; P < 0.0001]. Survival of G. mellonella larvae infected with NDM-1-expressing strains and controls was similar for E. coli J53 and K. pneumoniae PRZ. Cytotoxicity in A549 cells was not affected by NDM-1 expression (P > 0.05). The presence of blaNDM-1 did not increase the virulence or cytotoxicity of isogenic strains. However, there was a considerable cost of fitness incurred by carriage of the pNDM-1 plasmid. Interestingly, the cost of fitness was significantly higher in E. coli J53 compared with K. pneumoniae PRZ. PMID:27179815

  11. Clonal Dissemination of Enterobacter cloacae Harboring blaKPC-3 in the Upper Midwestern United States

    PubMed Central

    Hargreaves, Melissa L.; Shaw, Kristin M.; Dobbins, Ginette; Snippes Vagnone, Paula M.; Harper, Jane E.; Boxrud, Dave; Lynfield, Ruth; Aziz, Maliha; Price, Lance B.; Silverstein, Kevin A. T.; Danzeisen, Jessica L.; Youmans, Bonnie; Case, Kyle; Sreevatsan, Srinand

    2015-01-01

    Carbapenemase-producing, carbapenem-resistant Enterobacteriaceae, or CP-CRE, are an emerging threat to human and animal health, because they are resistant to many of the last-line antimicrobials available for disease treatment. Carbapenemase-producing Enterobacter cloacae harboring blaKPC-3 recently was reported in the upper midwestern United States and implicated in a hospital outbreak in Fargo, North Dakota (L. M. Kiedrowski, D. M. Guerrero, F. Perez, R. A. Viau, L. J. Rojas, M. F. Mojica, S. D. Rudin, A. M. Hujer, S. H. Marshall, and R. A. Bonomo, Emerg Infect Dis 20:1583–1585, 2014, http://dx.doi.org/10.3201/eid2009.140344). In early 2009, the Minnesota Department of Health began collecting and screening CP-CRE from patients throughout Minnesota. Here, we analyzed a retrospective group of CP-E. cloacae isolates (n = 34) collected between 2009 and 2013. Whole-genome sequencing and analysis revealed that 32 of the strains were clonal, belonging to the ST171 clonal complex and differing collectively by 211 single-nucleotide polymorphisms, and it revealed a dynamic clone under positive selection. The phylogeography of these strains suggests that this clone existed in eastern North Dakota and western Minnesota prior to 2009 and subsequently was identified in the Minneapolis and St. Paul metropolitan area. All strains harbored identical IncFIA-like plasmids conferring a CP-CRE phenotype and an additional IncX3 plasmid. In a single patient with multiple isolates submitted over several months, we found evidence that these plasmids had transferred from the E. cloacae clone to an Escherichia coli ST131 bacterium, rendering it as a CP-CRE. The spread of this clone throughout the upper midwestern United States is unprecedented for E. cloacae and highlights the importance of continued surveillance to identify such threats to human health. PMID:26438492

  12. Epidemiological Characteristics of blaNDM-1 in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii Complex in China from 2011 to 2012

    PubMed Central

    Ou, Weimei; Cui, Lanqing; Li, Yun; Zheng, Bo; Lv, Yuan

    2014-01-01

    Objectives The study aimed to investigate the prevalence and epidemiological characteristics of blaNDM-1 (encoding New Delhi metallo-β-lactamase 1) in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii complex (ABC) in China from July 2011 to June 2012. Methods PCR was used to screen for the presence of blaNDM-1 in all organisms studied. For blaNDM-1-positive strains, 16S rRNA analysis and Analytical Profile Index (API) strips were used to identify the bacterial genus and species. The ABCs were reconfirmed by PCR detection of blaOXA-51-like. Antibiotic susceptibilities of the bacteria were assessed by determining minimum inhibitory concentration (MIC) of them using two-fold agar dilution test, as recommended by the Clinical and Laboratory Standards Institute (CLSI). Molecular typing was performed using pulsed-field gel electrophoresis (PFGE). S1 nuclease-pulsed-field gel electrophoresis (S1-PFGE) and Southern blot hybridization were conducted to ascertain the gene location of blaNDM-1. Conjugation experiments were conducted to determine the transmission of blaNDM-1-positive strains. Results Among 2,170 Enterobacteriaceae and 600 ABCs, seven Enterobacteriaceae strains and two A. calcoaceticus isolates from five different cities carried the blaNDM-1 gene. The seven Enterobacteriaceae strains comprised four Klebsiella pneumoniae, one Enterobacter cloacae, one Enterobacter aerogen and one Citrobacter freundii. All seven were non-susceptible to imipenem, meropenem or ertapenem. Two A. calcoaceticus species were resistant to imipenem and meropenem. Three K. pneumoniae showed the same PFGE profiles. The blaNDM-1 genes of eight strains were localized on plasmids, while one was chromosomal. Conclusions Compared with previous reports, the numbers and species containing the blaNDM-1 in Enterobacteriaceae have significantly increased in China. Most of them are able to disseminate the gene, which is cause for concern. Consecutive surveillance should

  13. Dispersal of carbapenemase blaVIM-1 gene associated with different Tn402 variants, mercury transposons, and conjugative plasmids in Enterobacteriaceae and Pseudomonas aeruginosa.

    PubMed

    Tato, Marta; Coque, Teresa M; Baquero, Fernando; Cantón, Rafael

    2010-01-01

    The emergence of bla(VIM-1) within four different genetic platforms from distinct Enterobacteriaceae and Pseudomonas aeruginosa isolates in an area with a low prevalence of metallo-beta-lactamase producers is reported. Forty-three VIM-1-producing isolates (including 19 Enterobacter cloacae, 2 Escherichia coli, and 2 P. aeruginosa isolates, 18 Klebsiella pneumoniae isolate, and 2 Klebsiella oxytoca isolate) recovered from 2005 to 2007 and corresponding to 15 pulsed-field gel electrophoresis types were studied. The Enterobacteriaceae isolates corresponded to a hospital outbreak, and the P. aeruginosa isolates were sporadically recovered. The genetic context of the integrons carrying bla(VIM-1) (arbitrarily designated types A, B, C, and D) was characterized by PCR mapping based on known Tn402 and mercury transposons and further sequencing. Among Enterobacteriaceae isolates, bla(VIM-1) was part of integrons located either in an In2-Tn402 element linked to Tn21 (type A; In110-bla(VIM-1)-aacA4-aadA1) or in a Tn402 transposon lacking the whole tni module [type B; In113-bla(VIM-1)-aacA4-dhfrII (also called dfrB1)-aadA1-catB2] and the transposon was associated with an IncHI2 or IncI1 plasmid, respectively. Among P. aeruginosa isolates, bla(VIM-1) was part of a new gene cassette array located in a defective Tn402 transposon carrying either tniBDelta3 and tniA (type C; bla(VIM-1)-aadA1) or tniC and DeltatniQ (type D; bla(VIM-1)-aadB), and both Tn402 variants were associated with conjugative plasmids of 30 kb. The dissemination of bla(VIM-1) was associated with different genetic structures and bacterial hosts, depicting a complex emergence and evolutionary network scenario in our facility, Ramón y Cajal University Hospital, Madrid, Spain. Knowledge of the complex epidemiology of bla(VIM-1) is necessary to control this emerging threat. PMID:19901094

  14. Preponderance of Fis-binding sites in the R6K gamma origin and the curious effect of the penicillin resistance marker on replication of this origin in the absence of Fis.

    PubMed Central

    Wu, F; Wu, J; Ehley, J; Filutowicz, M

    1996-01-01

    Fis protein is shown here to bind to 10 sites in the gamma origin of plasmid R6K. The Fis-binding sites overlap all the previously identified binding sites in the gamma origin for the plasmid-encoded pi initiator protein and three host-encoded proteins, DnaA, integration host factor, and RNA polymerase. However, the requirement of Fis for R6K replication depends on the use of copy-up pi-protein variants and, oddly, the antibiotic resistance marker on the plasmid. In Fis-deficient cells, copy-up pi variants cannot drive replication of R6K gamma-origin plasmids carrying the bla gene encoding resistance to penicillin (Penr) but can drive replication of plasmids with the same origin but carrying the chloramphenicol acetyltransferase gene encoding chloramphenicol resistance (Cmr). In contrast, R6K replication driven by wild-type pi is unaffected by the antibiotic resistance marker in the absence of Fis protein. Individually, none of these elements (copy-up pi, Fis deficiency, or drug markers) prevents R6K replication. The replication defect is not caused by penicillin in the medium or runaway replication and is unaffected by the orientation of the bla gene relative to the origin. Replication remains inhibited when part of the bla coding segment is deleted but the bla promoter is left intact. However, replication is restored by insertion of transcriptional terminators on either side of the gamma origin, suggesting that excess transcription from the bla gene may inactivate replication driven by pi copy-up mutants in the absence of Fis. This study suggests that vector sequences such as drug markers may not be inconsequential in replication studies, as is generally assumed. PMID:8759862

  15. Whole-animal imaging of bacterial infection using endoscopic excitation of β-lactamase (BlaC)-specific fluorogenic probe

    NASA Astrophysics Data System (ADS)

    Nooshabadi, Fatemeh; Yang, Hee-Jeong; Cheng, Yunfeng; Xie, Hexin; Rao, Jianghong; Cirillo, Jeffrey D.; Maitland, Kristen C.

    2016-03-01

    Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains one of the most frequent causes of death worldwide. The slow growth rate of Mtb limits progress toward understanding tuberculosis including diagnosis of infections and evaluating therapeutic efficacy. Development of near-infrared (NIR) β-lactamase (BlaC)-specific fluorogenic substrate has made a significant breakthrough in the whole-animal imaging to detect Mtb infection. The reporter enzyme fluorescence (REF) system using a BlaC-specific fluorogenic substrate has improved the detection sensitivity in whole-animal optical imaging down to ~104 colony forming units (CFU) of bacteria, about 100-fold improvement over recombinant strains. However, improvement of detection sensitivity is strongly needed for clinical diagnosis of early stage infection at greater tissue depth. In order to improve detection sensitivity, we have integrated a fiber-based microendoscpe into a whole-animal imaging system to transmit the excitation light from the fiber bundle to the fluorescent target directly and measure fluorescent level using BlaC-specific REF substrate in the mouse lung. REF substrate, CNIR800, was delivered via aerosol route to the pulmonary infected mice with M. bovis BCG strain at 24 hours post-infection and groups of mice were imaged at 1-4 hours post-administration of the substrate using the integrated imaging system. In this study we evaluated the kinetics of CNIR800 substrate using REF technology using the integrated imaging system. Integration of these technologies has great promise for improved detection sensitivity allowing pre-clinical imaging for evaluation of new therapeutic agents.

  16. Association of blaOXA-23 and bap with the persistence of Acinetobacter baumannii within a major healthcare system

    PubMed Central

    Luo, Ting L.; Rickard, Alexander H.; Srinivasan, Usha; Kaye, Keith S.; Foxman, Betsy

    2015-01-01

    Objectives: Acinetobacter baumannii is an emerging opportunistic nosocomial pathogen. Two factors that may enhance persistence in healthcare settings are antimicrobial resistance and biofilm-forming ability. The aim of this work was to determine whether A. baumannii isolates that persist in healthcare settings (endemic), can be differentiated from sporadic isolates based upon their ability to resist antibiotics and their biofilm-forming capability. Methods: Two hundred and ninety A. baumannii isolates were isolated over 17 months in the Detroit Medical Center (DMC). The isolates were genotyped using repetitive extragenic palindromic-PCR (REP-PCR). REP-types appearing greater than 10 times during active surveillance were considered endemic. The in vitro biofilm-forming ability and antibiotic resistance profile of each isolate were evaluated. Isolates were tested for the presence of two genetic markers—one implicated in biofilm formation (bap) and the other in antibiotic resistance (blaOXA-23). Results: Of the 290 isolates evaluated, 84% carried bap and 36% carried blaOXA-23. Five unique REP-PCR banding-types were detected >10 times (endemic) and constituted 58% of the 290 isolates. These five endemic REP-PCR types were 5.1 times more likely than sporadic isolates to carry both bap and blaOXA-23. Furthermore, endemic isolates were resistant to 3 more antibiotic classes, on average, than sporadic isolates and four of the five endemic REP-PCR types formed denser biofilms in vitro than sporadic isolates. Conclusions: Endemic A. baumannii isolates are more likely than sporadic isolates to possess factors that increase virulence and enhance survival within a large healthcare system. PMID:25814985

  17. Different IncI1 plasmids from Escherichia coli carry ISEcp1-blaCTX-M-15 associated with different Tn2-derived elements.

    PubMed

    Zong, Zhiyong; Ginn, Andrew N; Dobiasova, Hana; Iredell, Jonathan R; Partridge, Sally R

    2015-07-01

    The bla(CTX-M-15) gene, encoding the globally dominant CTX-M-15 extended-spectrum β-lactamase, has generally been found in a 2.971-kb ISEcp1-bla(CTX-M-15)-orf477Δ transposition unit, with ISEcp1 providing a promoter. In available IncF plasmid sequences from Escherichia coli, this transposition unit interrupts a truncated copy of transposon Tn2 that lies within larger multiresistance regions. In E. coli, bla(CTX-M-15) is also commonly associated with IncI1 plasmids and here three such plasmids from E. coli clinical isolates from western Sydney 2006-2007 have been sequenced. The plasmid backbones are organised similarly to those of other IncI1 plasmids, but have insertions and/or deletions and sequence differences. Each plasmid also has a different insertion carrying bla(CTX-M-15). pJIE113 (IncI1 sequence type ST31) is almost identical to plasmids isolated from the 2011 E. coli O104:H4 outbreak in Europe, where the typical bla(CTX-M-15) transposition unit interrupts a complete Tn2 inserted directly in the plasmid backbone. In the novel plasmid pJIE139 (ST88), ISEcp1-blaC(TX-M-15)-orf477Δ lies within a Tn2/3 hybrid transposon. Homologous recombination could explain movement of ISEcp1-bla(CTX-M-15)-orf477Δ between copies of Tn2 on IncF and IncI1 plasmids and generation of the Tn2/3 hybrid. pJIE174 (ST37) is almost identical to pESBL-12 from the Netherlands and in these plasmids bla(CTX-M-15) is flanked by two copies of IS26 that truncate the transposition unit within a larger region bounded by the ends of Tn2. bla(CTX-M-15) and the associated ISEcp1-derived promoter may be able to move from this structure by the actions of IS26, independently of both ISEcp1 and Tn2. PMID:25929173

  18. Molecular characterization of carbapenem-resistant strains of Klebsiella pneumoniae isolated from Iranian patients: first identification of blaKPC gene in Iran.

    PubMed

    Nobari, Saman; Shahcheraghi, Fereshteh; Rahmati Ghezelgeh, Fatemeh; Valizadeh, Babak

    2014-08-01

    Multi-resistant Klebsiella pneumoniae has been considered a serious global threat. This study was initiated to investigate carbapenem resistance among K. pneumoniae isolates in Iran and to detect carbapenemases in resistant strains. From 2009 to 2012, 180 K. pneumoniae strains were collected from Tehran hospitals. Of the isolates, 42 isolates (23.3%) were resistant to meropenem, 29 isolates (16.1%) were resistant to ertapenem, and 14 isolates (7.7%) were resistant to imipenem. All of carbapenem-resistant isolates were also resistant to the third generation of cephalosporins. modified Hodge test was positive in 25 (59.5%) of carbapenem-resistant isolates showing carbapenemase production. bla(NDM) and bla(VIM) genes were identified in three and five carbapenem-resistant isolates, respectively. One isolate showed presence of bla(KPC) gene. Class 1 integrons were detected in 14 carbapenem-resistant isolates. The most important finding about class 1 integrons was identification of an integron containing metallo-β-lactamase gene VIM-1 that also harbored dfrA27 and arr3 genes. It is important to note that K. pneumoniae carbapenemase and New Delhi metallo-beta-lactamase-positive isolates identified in this study showed resistance to the majority of routine antimicrobial agents, including all β-lactams and other classes of antibiotics. To our knowledge, this is the first identification of bla(KPC) and bla(VIM-1) genes among isolates of K. pneumoniae in Iran. PMID:24428238

  19. Structures of Two Major Allergens, Bla g 4 and Per a 4, From Cockroaches and Their IgE Binding Epitopes

    SciTech Connect

    Tan, Y.; Chan, S; Ong, T; Yit, L; Tiong, Y; Chew, F; Sivaraman, J; Mok, Y

    2009-01-01

    Inhalant allergens from cockroaches are an important cause of asthma to millions of individuals worldwide. Here we report for the first time the structures of two major cockroach allergens, Bla g 4 and Per a 4, that adopt a typical lipocalin fold but with distinct structural features as compared with other known lipocalin allergens. Both Bla g 4 and Per a 4 contain two long-range disulfide bonds linking the N and C termini to a beta-barrel. The C-terminal helix of Bla g 4 is bent and greatly extended toward the N terminus. Bla g 4 is found to be a monomer, whereas Per a 4 exists as a dimer in solution with a novel dimeric interface involving residues from loops at the top and bottom of the beta-barrel. Putative ligand binding sites of both allergens are determined by docking of the juvenile hormone III inside the beta-barrel and found to interact with the ligand using non-conserved residues. Bla g 4 and Per a 4 are found to be cross-reactive in sera IgE binding, at least in the Singaporean Chinese population tested. A major IgE binding epitope unique to Per a 4 is found on the loops at the bottom of the beta-barrel that may aid the development of hypoallergens for immunotherapy.

  20. Complete Nucleotide Sequence of IncP-1β Plasmid pDTC28 Reveals a Non-Functional Variant of the blaGES-Type Gene.

    PubMed

    Dang, Bingjun; Mao, Daqing; Luo, Yi

    2016-01-01

    Plasmid pDTC28 was isolated from the sediments of Haihe River using E. coli CV601 (gfp-tagged) as recipient and indigenous bacteria from the sediment as donors. This plasmid confers reduced susceptibility to tetracycline and sulfamethoxazole. The complete sequence of plasmid pDTC28 was 61,503 bp in length with an average G+C content of 64.09%. Plasmid pDTC28 belongs to the IncP-1β group by phylogenetic analysis. The backbones of plasmid pDTC28 and other IncP-1β plasmids are very classical and conserved, whereas the accessory regions of these plasmids are diverse. A blaGES-5-like gene was found on the accessory region, and this blaGES-5-like gene contained 18 silent mutations and 7 missense mutations compared with the blaGES-5 gene. The mutations resulted in 7 amino acid substitutions in GES-5 carbapenemase, causing the loss of function of the blaGES-5-like gene on plasmid pDTC28 against carbapenems and even β-lactams. The enzyme produced by the blaGES-5-like gene cassette may be a new variant of GES-type enzymes. Thus, the plasmid sequenced in this study will expand our understanding of GES-type β-lactamases and provide insights into the genetic platforms used for the dissemination of GES-type genes. PMID:27152950

  1. Complete Nucleotide Sequence of IncP-1β Plasmid pDTC28 Reveals a Non-Functional Variant of the blaGES-Type Gene

    PubMed Central

    Dang, Bingjun; Mao, Daqing; Luo, Yi

    2016-01-01

    Plasmid pDTC28 was isolated from the sediments of Haihe River using E. coli CV601 (gfp-tagged) as recipient and indigenous bacteria from the sediment as donors. This plasmid confers reduced susceptibility to tetracycline and sulfamethoxazole. The complete sequence of plasmid pDTC28 was 61,503 bp in length with an average G+C content of 64.09%. Plasmid pDTC28 belongs to the IncP-1β group by phylogenetic analysis. The backbones of plasmid pDTC28 and other IncP-1β plasmids are very classical and conserved, whereas the accessory regions of these plasmids are diverse. A blaGES-5-like gene was found on the accessory region, and this blaGES-5-like gene contained 18 silent mutations and 7 missense mutations compared with the blaGES-5 gene. The mutations resulted in 7 amino acid substitutions in GES-5 carbapenemase, causing the loss of function of the blaGES-5-like gene on plasmid pDTC28 against carbapenems and even β-lactams. The enzyme produced by the blaGES-5-like gene cassette may be a new variant of GES-type enzymes. Thus, the plasmid sequenced in this study will expand our understanding of GES-type β-lactamases and provide insights into the genetic platforms used for the dissemination of GES-type genes. PMID:27152950

  2. Comparative characterization of the cephamycinase blaCMY-1 gene and its relationship with other beta-lactamase genes.

    PubMed Central

    Bauernfeind, A; Stemplinger, I; Jungwirth, R; Wilhelm, R; Chong, Y

    1996-01-01

    A plasmidic beta-lactamase which hydrolyzed cephamycins was first detected and reported in 1989. At that time its description was restricted to phenotypic characteristics. We analyzed nucleotide sequence of its gene and explored it genetic relationship with other bla genes. The deduced amino acid sequence of the blaCMY-1 product was compared with those of other known plasmidic cephamycinases and of chromosomal AmpC beta-lactamases. The results indicate that the relationship of CMY-1 is closest to MOX-1 among the plasmidic cephamycinases and to AmpC of Pseudomonas aeruginosa among the chromosomal cephalosporinases. We conclude that the plasmidic cephamycinases described up to now may be classified into three families, as follows: CMY-1, MOX-1, and FOX-1 with AmpC of P. aeruginosa; CMY-2, BIL-1 and LAT-1 with AmpC of Citrobacter freundii; and MIR-1 with AmpC of Enterobacter cloacae. Plasmidic cephamycinases are now recognized as clinically relevant class C beta-lactamases. PMID:8843306

  3. Characterization of Tn3000, a Transposon Responsible for blaNDM-1 Dissemination among Enterobacteriaceae in Brazil, Nepal, Morocco, and India

    PubMed Central

    Campos, Juliana Coutinho; da Silva, Maria José Félix; dos Santos, Paulo Roberto Nascimento; Barros, Elaine Menezes; Pereira, Mayne de Oliveira; Seco, Bruna Mara Silva; Magagnin, Cibele Massotti; Leiroz, Leonardo Kalab; de Oliveira, Théo Gremen Mimary; de Faria-Júnior, Célio; Cerdeira, Louise Teixeira; Barth, Afonso Luís; Sampaio, Suely Carlos Ferreira; Zavascki, Alexandre Prehn; Poirel, Laurent

    2015-01-01

    In Enterobacteriaceae, the blaNDM genes have been found in many different genetic contexts, and a wide diversity of plasmid scaffolds bearing those genes has been found. In August 2013, we identified NDM-1-producing Escherichia coli and Enterobacter hormaechei strains from a single rectal swab sample from a patient hospitalized in Rio de Janeiro, Brazil, who had no history of travel abroad. Complete DNA sequencing using the Illumina platform and annotation of the two plasmids harboring the blaNDM-1 gene, one from each strain, showed that they belonged to incompatibility groups IncFIIK and IncX3 and harbored a novel transposon named Tn3000. Similar genetic structures have been identified among other isolates in Brazil but also on plasmids from other continents. Our findings suggest that the blaNDM-1 gene may be transmitted by Tn3000 in different parts of the world. PMID:26392506

  4. Molecular Epidemiological Analysis of Escherichia coli Sequence Type ST131 (O25:H4) and blaCTX-M-15 among Extended-Spectrum-β-Lactamase-Producing E. coli from the United States, 2000 to 2009

    PubMed Central

    Urban, Carl; Weissman, Scott J.; Jorgensen, James H.; Lewis, James S.; Hansen, Glen; Edelstein, Paul H.; Robicsek, Ari; Cleary, Timothy; Adachi, Javier; Paterson, David; Quinn, John; Hanson, Nancy D.; Johnston, Brian D.; Clabots, Connie; Kuskowski, Michael A.

    2012-01-01

    Escherichia coli sequence type ST131 (from phylogenetic group B2), often carrying the extended-spectrum-β-lactamase (ESBL) gene blaCTX-M-15, is an emerging globally disseminated pathogen that has received comparatively little attention in the United States. Accordingly, a convenience sample of 351 ESBL-producing E. coli isolates from 15 U.S. centers (collected in 2000 to 2009) underwent PCR-based phylotyping and detection of ST131 and blaCTX-M-15. A total of 200 isolates, comprising 4 groups of 50 isolates each that were (i) blaCTX-M-15 negative non-ST131, (ii) blaCTX-M-15 positive non-ST131, (iii) blaCTX-M-15 negative ST131, or (iv) blaCTX-M-15 positive ST131, also underwent virulence genotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis (PFGE). Overall, 201 (57%) isolates exhibited blaCTX-M-15, whereas 165 (47%) were ST131. ST131 accounted for 56% of blaCTX-M-15-positive- versus 35% of blaCTX-M-15-negative isolates (P < 0.001). Whereas ST131 accounted for 94% of the 175 total group B2 isolates, non-ST131 isolates were phylogenetically distributed by blaCTX-M-15 status, with groups A (blaCTX-M-15-positive isolates) and D (blaCTX-M-15-negative isolates) predominating. Both blaCTX-M-15 and ST131 occurred at all participating centers, were recovered from children and adults, increased significantly in prevalence post-2003, and were associated with molecularly inferred virulence. Compared with non-ST131 isolates, ST131 isolates had higher virulence scores, distinctive virulence profiles, and more-homogeneous PFGE profiles. blaCTX-M-15 was associated with extensive antimicrobial resistance and ST131 with fluoroquinolone resistance. Thus, E. coli ST131 and blaCTX-M-15 are emergent, widely distributed, and predominant among ESBL-positive E. coli strains in the United States, among children and adults alike. Enhanced virulence and antimicrobial resistance have likely promoted the epidemiological success of these emerging public health

  5. Influence of agricultural practice on mobile bla genes: IncI1-bearing CTX-M, SHV, CMY and TEM in Escherichia coli from intensive farming soils.

    PubMed

    Jones-Dias, Daniela; Manageiro, Vera; Caniça, Manuela

    2016-01-01

    Many calls have been made to address antibiotic resistance in an environmental perspective. With this study, we showed the widespread presence of high-level antibiotic resistant isolates on a collection of non-susceptible Gram-negative bacteria (n = 232) recovered from soils. Bacteria were selected using amoxicillin, cefotaxime and imipenem, from sites representing different agricultural practices (extensive, intensive and organic). Striking levels of non-susceptibility were noticed in intensive soils for norfloxacin (74%), streptomycin (50.7%) and tetracycline (46.6%); indeed, the exposure to intensive agricultural practices constituted a risk factor for non-susceptibility to many antibiotics, multidrug resistance and production of extended-spectrum β-lactamases (ESBL). Analyses of non-susceptibility highlighted that environmental and clinical bacteria from the same species might not share the same intrinsic resistance patterns, raising concerns for therapy choices in environment-borne infections. The multiple sequence-type IncI1-driven spread of penicillinases (blaTEM-1, blaTEM-135), ESBL (blaSHV-12 and blaCTX-M-1) and plasmid-mediated AmpC β-lactamases (blaCMY-2), produced by isolates that share their molecular features with isolates from humans and animals, suggests contamination of agricultural soils. This is also the first appearance of IncI1/ST28-harbouring blaCTX-M-1, which should be monitored to prevent their establishment as successfully dispersed plasmids. This research may help disclose paths of contamination by mobile antibiotic resistance determinants and the risks for their dissemination. PMID:26279315

  6. Chromosomal Integration of the Extended-Spectrum β-Lactamase Gene blaCTX-M-15 in Salmonella enterica Serotype Concord Isolates from Internationally Adopted Children▿

    PubMed Central

    Fabre, Laëtitia; Delauné, Aurélia; Espié, Emmanuelle; Nygard, Karin; Pardos, Maria; Polomack, Lucette; Guesnier, Françoise; Galimand, Marc; Lassen, Jørgen; Weill, François-Xavier

    2009-01-01

    We report the emergence of Salmonella enterica isolates of serotype Concord (and its monophasic variant 6,7:l,v:-) producing the extended-spectrum β-lactamases (ESBLs) SHV-12 and CTX-M-15 in France and Norway between 2001 and 2006 (43 in France and 26 in Norway). The majority of these isolates were from adopted children from Ethiopia, most of whom were healthy carriers. Several symptomatic secondary cases were found in the adoptive families and health care facilities in France. Serotype Concord isolates collected before 2003 produced SHV-12 encoded on a 340-kb conjugative plasmid of replicon IncI1. Isolates collected after 2003 produced CTX-M-15. We detected two conjugative plasmids carrying blaCTX-M-15. One plasmid, approximately 300 kb in size, was positive for the IncHI2 replicon and the plasmid-mediated quinolone resistance gene qnrA1. The other plasmid, from one of the earliest CTX-M-15-producing isolates collected, was a fusion plasmid with IncY and IncA/C2 replicons and was 200 kb in size. However, we showed, using Southern hybridization of I-CeuI-digested chromosomal DNA and S1 nuclease analysis of plasmid DNA, that most isolates had a blaCTX-M-15 gene located on chromosomal DNA. Analysis of the flanking regions of the chromosomally located blaCTX-M-15 gene by cloning revealed an ISEcp1 truncated by an intact IS26 upstream from the blaCTX-M-15 gene and a truncated orf477 gene downstream from blaCTX-M-15. We found regions beyond the IS26 and the orf477 genes that were derived from IncA/C2 plasmids, suggesting the chromosomal integration of part of the blaCTX-M-15-carrying IncY and IncA/C2 fusion plasmid from early CTX-M-15-producing isolates. PMID:19273688

  7. Multidrug resistance and transferability of blaCTX-M among extended-spectrum β-lactamase-producing enteric bacteria in biofilm.

    PubMed

    Maheshwari, Meenu; Ahmad, Iqbal; Althubiani, Abdullah Safar

    2016-09-01

    This study aimed to investigate the occurrence of biofilm-forming extended-spectrum β-lactamase (ESBL)-producing enteric bacteria in hospital wastewater and to evaluate their antibiotic resistance behaviour and transferability of the plasmid-encoded blaCTX-M gene in biofilm. ESBL production was confirmed using the combined disc test and Etest. Amplification of blaCTX-M was performed by PCR. Antibiotic susceptibility was evaluated using the disc diffusion assay and broth dilution method. Transfer of blaCTX-M in planktonic and biofilm state was performed by broth mating and filter mating experiments, respectively. Among 110 enteric bacteria, 24 (21.8%) isolates belonging to Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae were found to produce ESBL and formed varying levels of biofilm in vitro. Presence of blaCTX-M was detected in 18 (75%) ESBL-producing isolates. A many fold increase in resistance to antibiotics was observed in biofilm. Among ESBL-producers, seven isolates could transfer the blaCTX-M gene by conjugation, with transfer frequencies ranging from 2.22×10(-4) to 7.14×10(-2) transconjugants/recipient cell in the planktonic state and from 3.04×10(-3) to 9.15×10(-1) in biofilm. The transfer frequency of blaCTX-M was significantly higher in biofilm compared with the planktonic state, and co-transfer of ciprofloxacin resistance was also detected in five isolates. This study demonstrates that biofilm-forming ESBL-producing enteric bacteria with a greater transfer frequency of resistance genes will lead to frequent dissemination of β-lactam and fluoroquinolone resistance genes in environmental settings. The emergence and spread of such multidrug resistance is a serious threat to animal and public health. PMID:27530857

  8. A Plasmid Bearing the bla(CTX-M-15) Gene and Phage P1-Like Sequences from a Sequence Type 11 Klebsiella pneumoniae Isolate.

    PubMed

    Shin, Juyoun; Ko, Kwan Soo

    2015-10-01

    Plasmid pKP12226 was extracted and analyzed from a CTX-M-15-producing Klebsiella pneumoniae sequence type 11 (ST11) isolate collected in South Korea. The plasmid represents chimeric characteristics consisting of a pIP1206-like backbone and lysogenized phage P1-like sequences. It bears a resistance region that includes resistance genes to several antibiotics and is different from previously characterized plasmids from South Korea bearing blaCTX-M-15. It may have resulted from recombination between an Escherichia coli plasmid backbone, a blaCTX-M-15-bearing resistance region, and lysogenized phage P1-like sequences. PMID:26195513

  9. Complete Nucleotide Sequence of pKOI-34, an IncL/M Plasmid Carrying blaIMP-34 in Klebsiella oxytoca Isolated in Japan.

    PubMed

    Shimada, Norimitsu; Kayama, Shizuo; Shigemoto, Norifumi; Hisatsune, Junzo; Kuwahara, Ryuichi; Nishio, Hisaaki; Yamasaki, Katsutoshi; Wada, Yasunao; Sueda, Taijiro; Ohge, Hiroki; Sugai, Motoyuki

    2016-05-01

    We determined the complete nucleotide sequence of a self-transmissible IncL/M plasmid, pKOI-34, from a Klebsiella oxytoca isolate. pKOI-34 possessed the core structure of an IncL/M plasmid found in Erwinia amylovora, pEL60, with two mobile elements inserted, a transposon carrying the arsenic resistance operon and a Tn21-like core module (tnp and mer modules) piggybacking blaIMP-34 as a class 1 integron, In808, where blaIMP-34 confers a resistance to carbapenems in K. oxytoca and Klebsiella pneumoniae. PMID:26902770

  10. High Prevalence of SXT/R391-Related Integrative and Conjugative Elements Carrying blaCMY-2 in Proteus mirabilis Isolates from Gulls in the South of France.

    PubMed

    Aberkane, Salim; Compain, Fabrice; Decré, Dominique; Dupont, Chloé; Laurens, Chrislène; Vittecoq, Marion; Pantel, Alix; Solassol, Jérôme; Carrière, Christian; Renaud, François; Brieu, Nathalie; Lavigne, Jean-Philippe; Bouzinbi, Nicolas; Ouédraogo, Abdoul-Salam; Jean-Pierre, Hélène; Godreuil, Sylvain

    2016-02-01

    The genetic structures involved in the dissemination of blaCMY-2 carried by Proteus mirabilis isolates recovered from different gull species in the South of France were characterized and compared to clinical isolates. blaCMY-2 was identified in P. mirabilis isolates from 27/93 yellow-legged gulls and from 37/65 slender-billed gulls. It was carried by a conjugative SXT/R391-like integrative and conjugative element (ICE) in all avian strains and in 3/7 human strains. Two clinical isolates had the same genetic background as six avian isolates. PMID:26643344

  11. Increased prevalence of carbapenem resistant Enterobacteriaceae in hospital setting due to cross-species transmission of the blaNDM-1 element and clonal spread of progenitor resistant strains

    PubMed Central

    Wang, Xuan; Chen, Gongxiang; Wu, Xiaoyan; Wang, Liangping; Cai, Jiachang; Chan, Edward W.; Chen, Sheng; Zhang, Rong

    2015-01-01

    This study investigated the transmission characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains collected from a hospital setting in China, in which consistent emergence of CRE strains were observable during the period of May 2013 to February 2014. Among the 45 CRE isolates tested, 21 (47%) strains were found to harbor the blaNDM-1 element, and the rest of 24 CRE strains were all positive for blaKPC-2. The 21 blaNDM-1—borne strains were found to comprise multiple Enterobacteriaceae species including nine Enterobacter cloacae, three Escherichia coli, three Citrobacter freundii, two Klebsiella pneumoniae, two Klebsiella oxytoca, and two Morganella morganii strains, indicating that cross-species transmission of blaNDM-1 is a common event. Genetic analyses by PFGE and MLST showed that, with the exception of E. coli and E. cloacae, strains belonging to the same species were often genetically unrelated. In addition to blaNDM-1, several CRE strains were also found to harbor the blaKPC-2, blaVIM-1, and blaIMP-4 elements. Conjugations experiments confirmed that the majority of carbapenem resistance determinants were transferable. Taken together, our findings suggest that transmission of mobile resistance elements among members of Enterobacteriaceae and clonal spread of CRE strains may contribute synergistically to a rapid increase in the population of CRE in clinical settings, prompting a need to implement more rigorous infection control measures to arrest such vicious transmission cycle in CRE-prevalent areas. PMID:26136735

  12. Draft genome sequence of a multidrug-resistant blaOXA-23-producing Acinetobacter baumannii ST208 isolate from China.

    PubMed

    Chen, Yan; Wu, Liyan; Chen, Yu; Xu, Zhijun; Xu, Liqun

    2016-03-01

    Acinetobacter baumannii has emerged worldwide as an important opportunistic nosocomial pathogen and has become a major public health concern. In this study, the draft genome sequence of A. baumannii TCM331 (ST208/CC92), a multidrug-resistant (MDR) isolate harbouring the blaOXA-23 gene isolated in China, was determined. The genome of TCM331 was sequenced via Illumina HiSeq™ 2000, and bioinformatics analysis was performed. Important antimicrobial resistance determinants were observed in an estimated genome size of 4,058,691bp with 3838 predicted coding regions. In conclusion, these data might facilitate further understanding of the specific genomic features of MDR A. baumannii in China. PMID:27436391

  13. In silico prediction of the T-cell and IgE-binding epitopes of Per a 6 and Bla g 6 allergens in cockroaches.

    PubMed

    Chen, Hao; Yang, Hai-Wei; Wei, Ji-Fu; Tao, Ai-Lin

    2014-10-01

    Per a 6 and Bla g 6 are cockroach allergens found in Periplaneta americana and Blattella germanica, respectively. The objective of the present study was to predict the B‑ and T‑cell epitopes of the Per a 6 and Bla g 6 allergens. Three immunoinformatics tools, the DNAStar Protean system, the Bioinformatics Predicted Antigenic Peptides system and the BepiPred 1.0 server, were used to predict the potential B‑cell epitopes, while Net‑MHCIIpan‑2.0 and NetMHCII‑2.2 were used to predict the T‑cell epitopes of the two allergens. As a result, seven peptides were predicted in the Per a 6 allergen and seven peptides were predicted in the Bla g 6 allergen in the B‑cell epitope predictions. In the T‑cell prediction, the Per a 6 allergen was predicted to have nine strongly binding nonamer core epitope sequences (IC50<50 nm) and 28 weakly binding sequences (50 nmBla g 6 allergen was predicted to have nine strong binders and 25 weak binders. These results may be useful for peptide‑based vaccine designs. PMID:25050891

  14. A Carbapenem-Resistant Pseudomonas aeruginosa Isolate Harboring Two Copies of blaIMP-34 Encoding a Metallo-β-Lactamase

    PubMed Central

    Tada, Tatsuya; Miyoshi-Akiyama, Tohru; Shimada, Kayo; Shiroma, Akino; Nakano, Kazuma; Teruya, Kuniko; Satou, Kazuhito; Hirano, Takashi; Shimojima, Masahiro; Kirikae, Teruo

    2016-01-01

    A carbapenem-resistant strain of Pseudomonas aeruginosa, NCGM1984, was isolated in 2012 from a hospitalized patient in Japan. Immunochromatographic assay showed that the isolate was positive for IMP-type metallo-β-lactamase. Complete genome sequencing revealed that NCGM1984 harbored two copies of blaIMP-34, located at different sites on the chromosome. Each blaIMP-34 was present in the same structures of the class 1 integrons, tnpA(ISPa7)-intI1-qacG-blaIMP-34-aac(6')-Ib-qacEdelta1-sul1-orf5-tniBdelta-tniA. The isolate belonged to multilocus sequence typing ST235, one of the international high-risk clones. IMP-34, with an amino acid substitution (Glu126Gly) compared with IMP-1, hydrolyzed all β-lactamases tested except aztreonam, and its catalytic activities were similar to IMP-1. This is the first report of a clinical isolate of an IMP-34-producing P. aeruginosa harboring two copies of blaIMP-34 on its chromosome. PMID:27055243

  15. Molecular Analysis of the Sequences Surrounding blaOXA-45 Reveals Acquisition of This Gene by Pseudomonas aeruginosa via a Novel ISCR Element, ISCR5▿

    PubMed Central

    Li, Hongyang; Walsh, Timothy R.; Toleman, Mark A.

    2009-01-01

    The blaOXA-45 gene of Pseudomonas aeruginosa 07-406 is driven by a promoter found within a truncated ISPme1 insertion sequence. The gene is located between nonidentical repeats of a new ISCR element, ISCR5, which is likely responsible for its acquisition. Sequence analysis indicates that ISCR5 is a chimera of ISCR3 and ISCR16. PMID:19064894

  16. Complete Nucleotide Sequence of pGA45, a 140,698-bp IncFIIY Plasmid Encoding bla IMI-3-Mediated Carbapenem Resistance, from River Sediment.

    PubMed

    Dang, Bingjun; Mao, Daqing; Luo, Yi

    2016-01-01

    Plasmid pGA45 was isolated from the sediments of Haihe River using Escherichia coli CV601 (gfp-tagged) as recipients and indigenous bacteria from sediment as donors. This plasmid confers reduced susceptibility to imipenem which belongs to carbapenem group. Plasmid pGA45 was fully sequenced on an Illumina HiSeq 2000 sequencing system. The complete sequence of plasmid pGA45 was 140,698 bp in length with an average G + C content of 52.03%. Sequence analysis shows that pGA45 belongs to IncFIIY group and harbors a backbone region which shares high homology and gene synteny to several other IncF plasmids including pNDM1_EC14653, pYDC644, pNDM-Ec1GN574, pRJF866, pKOX_NDM1, and pP10164-NDM. In addition to the backbone region, plasmid pGA45 harbors two notable features including one bla IMI-3-containing region and one type VI secretion system region. The bla IMI-3-containing region is responsible for bacteria carbapenem resistance and the type VI secretion system region is probably involved in bacteria virulence, respectively. Plasmid pGA45 represents the first complete nucleotide sequence of the bla IMI-harboring plasmid from environment sample and the sequencing of this plasmid provided insight into the architecture used for the dissemination of bla IMI carbapenemase genes. PMID:26941718

  17. The IncP-6 Plasmid p10265-KPC from Pseudomonas aeruginosa Carries a Novel ΔISEc33-Associated bla KPC-2 Gene Cluster.

    PubMed

    Dai, Xiaotian; Zhou, Dongsheng; Xiong, Wei; Feng, Jiao; Luo, Wenbo; Luo, Guangming; Wang, Haijing; Sun, Fengjun; Zhou, Xiangdong

    2016-01-01

    Pseudomonas aeruginosa strain 10265 was recovered from a patient with pneumonia in a Chinese public hospital, and it displays the carbapenem resistance phenotype due to the acquisition of a non-conjugative but mobilizable IncP-6-type plasmid p10265-KPC. p10265-KPC carries a Tn5563-borne defective mer locus, and a novel ΔISEc33-associated bla KPC-2 gene cluster without paired inverted repeats and paired direct repeats at both ends. Mobilization of this ΔISEc33-associated element in p10265-KPC would be attributed to homologous recombination-based insertion of a foreign structure Tn3-ISApu1-orf7-ISApu2- ISKpn27-Δbla TEM-1 -bla KPC-2 -ΔISKpn6- korC-orf6-klcA-ΔrepB into a pre-existent intact ISEc33, making ISEc33 truncated at the 3' end. The previously reported pCOL-1 represents the first sequenced KPC-producing IncP-6 plasmid, while p10265-KPC is the second one. These two plasmids carry two distinct bla KPC-2 gene clusters, which are inserted into the different sites of the IncP-6 backbone and have different evolutionary histories of assembly and mobilization. This is the first report of identification of the IncP-6-type resistance plasmid in China. PMID:27014233

  18. The IncP-6 Plasmid p10265-KPC from Pseudomonas aeruginosa Carries a Novel ΔISEc33-Associated blaKPC-2 Gene Cluster

    PubMed Central

    Dai, Xiaotian; Zhou, Dongsheng; Xiong, Wei; Feng, Jiao; Luo, Wenbo; Luo, Guangming; Wang, Haijing; Sun, Fengjun; Zhou, Xiangdong

    2016-01-01

    Pseudomonas aeruginosa strain 10265 was recovered from a patient with pneumonia in a Chinese public hospital, and it displays the carbapenem resistance phenotype due to the acquisition of a non-conjugative but mobilizable IncP-6-type plasmid p10265-KPC. p10265-KPC carries a Tn5563-borne defective mer locus, and a novel ΔISEc33-associated blaKPC-2 gene cluster without paired inverted repeats and paired direct repeats at both ends. Mobilization of this ΔISEc33-associated element in p10265-KPC would be attributed to homologous recombination-based insertion of a foreign structure Tn3-ISApu1-orf7-ISApu2- ISKpn27-ΔblaTEM-1-blaKPC-2-ΔISKpn6- korC-orf6-klcA-ΔrepB into a pre-existent intact ISEc33, making ISEc33 truncated at the 3′ end. The previously reported pCOL-1 represents the first sequenced KPC-producing IncP-6 plasmid, while p10265-KPC is the second one. These two plasmids carry two distinct blaKPC-2 gene clusters, which are inserted into the different sites of the IncP-6 backbone and have different evolutionary histories of assembly and mobilization. This is the first report of identification of the IncP-6-type resistance plasmid in China. PMID:27014233

  19. Complete Nucleotide Sequence of pGA45, a 140,698-bp IncFIIY Plasmid Encoding blaIMI-3-Mediated Carbapenem Resistance, from River Sediment

    PubMed Central

    Dang, Bingjun; Mao, Daqing; Luo, Yi

    2016-01-01

    Plasmid pGA45 was isolated from the sediments of Haihe River using Escherichia coli CV601 (gfp-tagged) as recipients and indigenous bacteria from sediment as donors. This plasmid confers reduced susceptibility to imipenem which belongs to carbapenem group. Plasmid pGA45 was fully sequenced on an Illumina HiSeq 2000 sequencing system. The complete sequence of plasmid pGA45 was 140,698 bp in length with an average G + C content of 52.03%. Sequence analysis shows that pGA45 belongs to IncFIIY group and harbors a backbone region which shares high homology and gene synteny to several other IncF plasmids including pNDM1_EC14653, pYDC644, pNDM-Ec1GN574, pRJF866, pKOX_NDM1, and pP10164-NDM. In addition to the backbone region, plasmid pGA45 harbors two notable features including one blaIMI-3-containing region and one type VI secretion system region. The blaIMI-3-containing region is responsible for bacteria carbapenem resistance and the type VI secretion system region is probably involved in bacteria virulence, respectively. Plasmid pGA45 represents the first complete nucleotide sequence of the blaIMI-harboring plasmid from environment sample and the sequencing of this plasmid provided insight into the architecture used for the dissemination of blaIMI carbapenemase genes. PMID:26941718

  20. IncN plasmids carrying bla CTX-M-1 in Escherichia coli isolates on a dairy farm.

    PubMed

    Dolejska, Monika; Jurcickova, Zuzana; Literak, Ivan; Pokludova, Lucie; Bures, Jiri; Hera, Alfred; Kohoutova, Ludmila; Smola, Jiri; Cizek, Alois

    2011-05-01

    The aim of the study was to compare the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli bovine isolates on a conventional dairy cattle farm with high consumption of parenteral and intramammary cephalosporins (farm A) and on an organic dairy farm with no cephalosporin use (farm B). ESBL-producing E. coli were isolated from rectal swabs and milk filters by selective cultivation on MacConkey agar with cefotaxime (2mg/l). ESBL genes were identified by polymerase chain reaction (PCR) and sequencing, and the genetic diversity of the isolates was determined by XbaI pulsed field gel electrophoresis (PFGE). Conjugative transfer, incompatibility group, and restriction fragment length polymorphism (RFLP) profiles of the ESBL-carrying plasmids were studied. Higher prevalence (39%, n(rectal samples in cows)=309) of CTX-M-1-producing E. coli isolates was found on farm A compared to farm B (<1%, n(rectal samples in cows)=154; 0%, n(rectal samples in calves)=46). Using PFGE, the isolates from farm A were divided into nine pulsotypes. In all ESBL-positive isolates, the bla(CTX-M-1) gene was carried on 40 kb IncN conjugative plasmids of three related HincII restriction profiles. Horizontal gene transfer through transmission of IncN plasmids harboring bla(CTX-M-1) as well as clonal dissemination of a particular clone seems to be involved in dissemination of CTX-M-1-producing E. coli isolates in cows on the farm using cephalosporins in treating bacterial infections. The study demonstrates a possible role of cephalosporin use in the widespread occurrence of CTX-M-1-producing E. coli on the conventional dairy cattle farm compared to the organic farm. PMID:21276666

  1. Carbapenem-resistant Acinetobacter baumannii from Brazil: role of carO alleles expression and blaOXA-23 gene

    PubMed Central

    2013-01-01

    Background Carbapenems are the antibiotics of choice to treat infections caused by Acinetobacter baumannii, and resistance to this class can be determined by loss of membrane permeability and enzymatic mechanisms. Here, we analyzed the basis of carbapenem resistance in clinical A. baumannii isolates from different Brazilian regions. Results The analyses addressed the carbapenemase activity of OXA-23, CarO expression and alterations in its primary structure. Susceptibility test revealed that the strains presented the COS (Colistin-Only-Sensitive) profile. PCR and sequencing showed the presence of the chromosomally-encoded blaOXA-51 in all isolates. The majority of strains (53%) carried the carbapenemase blaOXA-23 gene associated with ISAba1. The Hodge test indicated that these strains are carbapenemase producers. PFGE revealed 14 genotypes among strains from Rio de Janeiro and Maranhão. The influence of carO on imipenem resistance was evaluated considering two aspects: the composition of the primary amino acid sequence; and the expression level of this porin. Sequencing and in silico analyses showed the occurrence of CarOa, CarOb and undefined CarO types, and Real Time RT-PCR revealed basal and reduced carO transcription levels among isolates. Conclusions We concluded that, in general, for these Brazilian isolates, the major carbapenem resistance mechanism was due to OXA-23 carbapenemase activity and that loss of CarO porin plays a minor role in this phenotype. However, it was possible to associate the carO alleles and their expression with imipenem resistance. Therefore, these findings underline the complexity in addressing the role of different mechanisms in carbapenem resistance and highlight the possible influence of CarO type in this phenotype. PMID:24195496

  2. First report of novel genetic array aacA4-blaIMP-25-oxa30-catB3 and identification of novel metallo-β-lactamase gene blaIMP25: A Retrospective Study of antibiotic resistance surveillance on Psuedomonas aeruginosa in Guangzhou of South China, 2003-2007.

    PubMed

    Yu, Guangchao; Wen, Wangrong; Peters, Brian M; Liu, Junyan; Ye, Congxiu; Che, Yuchuan; Liu, Juzhen; Cao, Kaiyuan; Xu, Zhenbo; Shirtliff, Mark E

    2016-06-01

    Carbapenem, imipenem and meropenem have been broadly prescribed contributing to the global occurrence and prevalence of carbapenem resistance in Psuedomonas aeruginosa, and the associated resistance genotypes remains clinically significant. A retrospective surveillance had been conducted on 499 P. aeruginosa isolates in South China during 2003-2007, including antimicrobial resistance and characterization of MBLs on carbapenem-resistant strains. One hundred and sixty-four out of 499 strains were carbapenem-resistant, with 11, 4 and 5 strains positive for blaIMP-9, blaIMP-25 and blaVIM-2, respectively. Sixteen out of 20 isolates were positive for intI1 and contained identical flanking regions (as indicated in KM384735), and all tested isolates containing the qacE△1-sul1 of the typical 3'-conserved region. A novel blaIMP-25 metallo-β-lactamase and a genetic array of aacA4-blaIMP-25-oxa30-catB3 have been discovered from this retrospective surveillance on antimicrobial resistance of P. aeruginosa. PMID:26997650

  3. Identification of VIM-2-Producing Pseudomonas aeruginosa from Tanzania Is Associated with Sequence Types 244 and 640 and the Location of blaVIM-2 in a TniC Integron

    PubMed Central

    Moyo, Sabrina; Haldorsen, Bjørg; Aboud, Said; Blomberg, Bjørn; Maselle, Samuel Y.; Sundsfjord, Arnfinn; Langeland, Nina

    2014-01-01

    Epidemiological data on carbapenemase-producing Gram-negative bacteria on the African continent are limited. Here, we report the identification of VIM-2-producing Pseudomonas aeruginosa isolates in Tanzania. Eight out of 90 clinical isolates of P. aeruginosa from a tertiary care hospital in Dar es Salaam were shown to harbor blaVIM-2. The blaVIM-2-positive isolates belonged to two different sequence types (ST), ST244 and ST640, with blaVIM-2 located in an unusual integron structure lacking the 3′ conserved region of qacΔE1-sul1. PMID:25331700

  4. Spread of blaCTX-M-14 Is Driven Mainly by IncK Plasmids Disseminated among Escherichia coli Phylogroups A, B1, and D in Spain▿

    PubMed Central

    Valverde, Aránzazu; Cantón, Rafael; Garcillán-Barcia, M. Pilar; Novais, Ângela; Galán, Juan Carlos; Alvarado, Andrés; de la Cruz, Fernando; Baquero, Fernando; Coque, Teresa M.

    2009-01-01

    Since its first description in 2000, CTX-M-14 has become one of the most widespread extended-spectrum β-lactamases in Spain. In the present Escherichia coli multilevel population genetic study involving the characterization of phylogroups, clones, plasmids, and genetic platforms, 61 isolates from 16 hospitalized patients and 40 outpatients and healthy volunteers recovered from 2000 to 2005 were analyzed. Clonal relatedness (XbaI pulsed-field gel electrophoresis [PFGE] type, phylogenetic group, multilocus sequence type [MLST]) was established by standard methods. Analysis of transferred plasmids (I-CeuI; S1 nuclease; restriction fragment length polymorphism analysis; and analysis of RNA interference, replicase, and relaxase) was performed by PCR, sequencing, and hybridization. The genetic environment of blaCTX-M-14 was characterized by PCR on the basis of known associated structures (ISEcp1, IS903, ISCR1). The isolates were mainly recovered from patients in the community (73.8%; 45/61) with urinary tract infections (62.2%; 28/45). They were clonally unrelated by PFGE and corresponded to phylogenetic groups A (36.1%), D (34.4%), and B1 (29.5%). MLST revealed a high degree of sequence type (ST) diversity among phylogroup D isolates and the overrepresentation of the ST10 complex among phylogroup A isolates and ST359/ST155 among phylogroup B1 isolates. Two variants of blaCTX-M-14 previously designated blaCTX-M-14a (n = 59/61) and blaCTX-M-14b (n = 2/61) were detected. blaCTX-M-14a was associated with either ISEcp1 within IncK plasmids (n = 27), ISCR1 linked to an IncHI2 plasmid (n = 1), or ISCR1 linked to IncI-like plasmids (n = 3). The blaCTX-M-14b identified was associated with an ISCR1 element located in an IncHI2 plasmid (n = 1) or with ISEcp1 located in IncK (n = 1). The CTX-M-14-producing E. coli isolates in our geographic area are frequent causes of community-acquired urinary tract infections. The increase in the incidence of such isolates is mostly due to the

  5. Phosphorylation of BlaR1 in Manifestation of Antibiotic Resistance in Methicillin-Resistant Staphylococcus aureus and Its Abrogation by Small Molecules.

    PubMed

    Boudreau, Marc A; Fishovitz, Jennifer; Llarrull, Leticia I; Xiao, Qiaobin; Mobashery, Shahriar

    2015-10-01

    Methicillin-resistant Staphylococcus aureus (MRSA), an important human pathogen, has evolved an inducible mechanism for resistance to β-lactam antibiotics. We report herein that the integral membrane protein BlaR1, the β-lactam sensor/signal transducer protein, is phosphorylated on exposure to β-lactam antibiotics. This event is critical to the onset of the induction of antibiotic resistance. Furthermore, we document that BlaR1 phosphorylation and the antibiotic-resistance phenotype are both reversed in the presence of synthetic protein kinase inhibitors of our design, restoring susceptibility of the organism to a penicillin, resurrecting it from obsolescence in treatment of these intransigent bacteria. PMID:27623311

  6. Plasmid Profile Analysis and bla VIM Gene Detection of Metalo β-lactamase (MBL) Producing Pseudomonas aeruginosa Isolates from Clinical Samples

    PubMed Central

    M, Jeya

    2014-01-01

    Introduction:Pseudomonas aeruginosa is a frequent colonizer of hospitalized patients. They are responsible for serious infections such as meningitis, urological infections, septicemia and pneumonia. Carbapenem resistance of Pseudomonas aeruginosa is currently increasingly reported which is often mediated by production of metallo-β-lactamase (MBL). Multidrug resistant Pseudomonas aeruginosa isolates may involve reduced cell wall permeability, production of chromosomal and plasmid mediated β lactamases, aminoglycosides modifying enzymes and an active multidrug efflux mechanism. Objective: This study is aimed to detect the presence and the nature of plasmids among metallo-β-lactamase producing Pseudomonas aeruginosa isolates. Also to detect the presence of bla VIM gene from these isolates. Materials and Methods: Clinical isolates of Pseudomonas aeruginosa showing the metalo-β-lactamase enzyme (MBL) production were isolated. The MBL production was confirmed by three different methods. From the MBL producing isolates plasmid extraction was done by alkaline lysis method. Plasmid positive isolates were subjected for blaVIM gene detection by PCR method. Results: Two thousand seventy six clinical samples yielded 316 (15.22%) Pseudomonas aeruginosa isolates, out of which 141 (44.62%) were multidrug resistant. Among them 25 (17.73%) were metallo-β-lactamase enzyme producers. Plasmids were extracted from 18 out of 25 isolates tested. Five out of 18 isolates were positive for the blaVIM gene detection by the PCR amplification. Conclusion: The MBL producers were susceptible to polymyxin /colistin with MIC ranging from 0.5 – 2μg/ml. Molecular detection of specific genes bla VIM were positive among the carbapenem resistant isolates. PMID:25120980

  7. Vibrio cholerae InV117, a Class 1 Integron Harboring aac(6′)-Ib and blaCTX-M-2, Is Linked to Transposition Genes

    PubMed Central

    Soler Bistué, Alfonso J. C.; Martín, Fernando A.; Petroni, Alejandro; Faccone, Diego; Galas, Marcelo; Tolmasky, Marcelo E.; Zorreguieta, Angeles

    2006-01-01

    A ca. 150-kbp Vibrio cholerae O1 biotype El Tor plasmid includes blaCTX-M-2 and a variant of aac(6′)-Ib within InV117, an orf513-bearing class 1 integron. InV117 is linked to a tnp1696 module in which IRl carries an insertion of IS4321R. The complete structure could be a potential mobile element. PMID:16641475

  8. Draft genome sequence of blaVeb-1, blaoxa-10producing multi-drug resistant (MDR) Pseudomonas aeruginosastrain VRFPA09 recovered from bloodstream infection

    PubMed Central

    Murugan, Nandagopal; Malathi, Jambulingam; Umashankar, Vetrivel; Madhavan, Hajib NarahariRao

    2015-01-01

    Pseudomonas aeruginosa (P. aeruginosa) bacteremia causes significant mortality rate due to emergence of multidrug resistant (MDR) nosocomial infections. We report the draft genome sequence of P. aeruginosa strain VRFPA09, a human bloodstream isolate, phenotypically proven as MDR strain. Whole genome sequencing on VRFPA09, deciphered betalactamase encoding blaveb-1 and blaOXA-10genes and multiple drug resistance, virulence factor encoding genes. PMID:26413042

  9. Draft genome sequence of blaVeb-1, blaoxa-10 producing multi-drug resistant (MDR) Pseudomonas aeruginosa strain VRFPA09 recovered from bloodstream infection.

    PubMed

    Murugan, Nandagopal; Malathi, Jambulingam; Umashankar, Vetrivel; Madhavan, Hajib NarahariRao

    2015-01-01

    Pseudomonas aeruginosa (P. aeruginosa) bacteremia causes significant mortality rate due to emergence of multidrug resistant (MDR) nosocomial infections. We report the draft genome sequence of P. aeruginosa strain VRFPA09, a human bloodstream isolate, phenotypically proven as MDR strain. Whole genome sequencing on VRFPA09, deciphered betalactamase encoding blav(eb-1) and bla(OXA-10) genes and multiple drug resistance, virulence factor encoding genes. PMID:26413042

  10. Complex integrons containing qnrB4-ampC (bla(DHA-1)) in plasmids of multidrug-resistant Citrobacter freundii from wastewater.

    PubMed

    Yim, Grace; Kwong, Waldan; Davies, Julian; Miao, Vivian

    2013-02-01

    Microbial populations in wastewater treatment plants (WWTPs) are increasingly being recognized as environmental reservoirs of antibiotic resistance genes. PCR amplicons for plasmid-mediated quinolone resistance determinants qnrA, qnrB, and qnrS were recorded in samples from a WWTP in Vancouver, British Columbia. Six strains of ciprofloxacin-resistant Citrobacter freundii were isolated and found to carry mutations in gyrA and parC, as well as multiple plasmid-borne resistance genes, collectively including qnrB; aac(6')-Ib-cr; β-lactamase-encoding genes from molecular classes A (blaTEM-1), C (ampC), D (blaOXA-1, blaOXA-10); and genes for resistance to 5 other types of antibiotics. In 3 strains, large (>60 kb) plasmids carried qnrB4 and ampC as part of a complex integron in a 14 kb arrangement that has been reported worldwide but, until recently, only among pathogenic strains of Klebsiella. Analysis of single-nucleotide polymorphisms in the qnrB4-ampC regions infers 2 introductions into the WWTP environment. These results suggest recent passage of plasmid-borne fluoroquinolone and β-lactam resistance genes from pathogens to bacteria that may be indigenous inhabitants of WWTPs, thus contributing to an environmental pool of antibiotic resistance. PMID:23461518

  11. Crystal Structure of Cockroach Allergen Bla g 2, an Unusual Zinc Binding Aspartic Protease with a Novel Mode of Self-inhibition

    SciTech Connect

    Gustchina, Alla; Li, Mi; Wunschmann, Sabina; Chapman, Martin D.; Pomes, Anna; Wlodawer, Alexander

    2010-07-19

    The crystal structure of Bla g 2 was solved in order to investigate the structural basis for the allergenic properties of this unusual protein. This is the first structure of an aspartic protease in which conserved glycine residues, in two canonical DTG triads, are substituted by different amino acid residues. Another unprecedented feature revealed by the structure is the single phenylalanine residue insertion on the tip of the flap, with the side-chain occupying the S1 binding pocket. This and other important amino acid substitutions in the active site region of Bla g 2 modify the interactions in the vicinity of the catalytic aspartate residues, increasing the distance between them to {approx}4 {angstrom} and establishing unique direct contacts between the flap and the catalytic residues. We attribute the absence of substantial catalytic activity in Bla g 2 to these unusual features of the active site. Five disulfide bridges and a Zn-binding site confer stability to the protein, which may contribute to sensitization at lower levels of exposure than other allergens.

  12. Identification and characterization of a novel aac(6')-Iag associated with the blaIMP-1-integron in a multidrug-resistant Pseudomonas aeruginosa.

    PubMed

    Kobayashi, Kanao; Hayashi, Ikue; Kouda, Syuntaro; Kato, Fuminori; Fujiwara, Tamaki; Kayama, Shizuo; Hirakawa, Hideki; Itaha, Hideyuki; Ohge, Hiroki; Gotoh, Naomasa; Usui, Tsuguru; Matsubara, Akio; Sugai, Motoyuki

    2013-01-01

    In a continuing study from Dec 2006 to Apr 2008, we characterized nine multi-drug resistant Pseudomonas aeruginosa strains isolated from four patients in a ward at the Hiroshima University Hospital, Japan. Pulsed-field gel electrophoresis of SpeI-digested genomic DNAs from the isolates suggested the clonal expansion of a single strain; however, only one strain, NK0009, was found to produce metallo-β-lactamase. PCR and subsequent sequencing analysis indicated NK0009 possessed a novel class 1 integron, designated as In124, that carries an array of four gene cassettes: a novel aminoglycoside (AG) resistance gene, aac(6')-Iag, blaIMP-1, a truncated form of blaIMP-1, and a truncated form of aac(6')-Iag. The aac(6')-Iag encoded a 167-amino-acid protein that shows 40% identity with AAC(6')-Iz. Recombinant AAC(6')-Iag protein showed aminoglycoside 6'-N-acetyltransferase activity using thin-layer chromatography (TLC) and MS spectrometric analysis. Escherichia coli carrying aac(6')-Iag showed resistance to amikacin, arbekacin, dibekacin, isepamicin, kanamycin, sisomicin, and tobramycin; but not to gentamicin. A conjugation experiment and subsequent Southern hybridization with the gene probes for blaIMP-1 and aac(6')-Ig strongly suggested In124 is on a conjugal plasmid. Transconjugants acquired resistance to gentamicin and were resistant to virtually all AGs, suggesting that the In124 conjugal plasmid also possesses a gene conferring resistance to gentamicin. PMID:23950962

  13. Original Misunderstanding

    ERIC Educational Resources Information Center

    Holtzman, Alexander

    2009-01-01

    Humorist Josh Billings quipped, "About the most originality that any writer can hope to achieve honestly is to steal with good judgment." Billings was harsh in his view of originality, but his critique reveals a tension faced by students every time they write a history paper. Research is the essence of any history paper. Especially in high school,…

  14. Clinical Performance of a Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method for Detection of Certain blaKPC-Containing Plasmids

    PubMed Central

    Youn, Jung-Ho; Drake, Steven K.; Weingarten, Rebecca A.; Frank, Karen M.; Dekker, John P.

    2015-01-01

    Rapid detection of blaKPC-containing organisms can significantly impact infection control and clinical practices, as well as therapeutic choices. Current molecular and phenotypic methods to detect these organisms, however, require additional testing beyond routine organism identification. In this study, we evaluated the clinical performance of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) to detect pKpQIL_p019 (p019)—an ∼11,109-Da protein associated with certain blaKPC-containing plasmids that was previously shown to successfully track a clonal outbreak of blaKPC-pKpQIL-Klebsiella pneumoniae in a proof-of-principle study (A. F. Lau, H. Wang, R. A. Weingarten, S. K. Drake, A. F. Suffredini, M. K. Garfield, Y. Chen, M. Gucek, J. H. Youn, F. Stock, H. Tso, J. DeLeo, J. J. Cimino, K. M. Frank, and J. P. Dekker, J Clin Microbiol 52:2804–2812, 2014, http://dx.doi.org/10.1128/JCM.00694-14). PCR for the p019 gene was used as the reference method. Here, blind analysis of 140 characterized Enterobacteriaceae isolates using two protein extraction methods (plate extraction and tube extraction) and two peak detection methods (manual and automated) showed sensitivities and specificities ranging from 96% to 100% and from 95% to 100%, respectively (2,520 spectra analyzed). Feasible laboratory implementation methods (plate extraction and automated analysis) demonstrated 96% sensitivity and 99% specificity. All p019-positive isolates (n = 26) contained blaKPC and were carbapenem resistant. Retrospective analysis of an additional 720 clinical Enterobacteriaceae spectra found an ∼11,109-Da signal in nine spectra (1.3%), including seven from p019-containing, carbapenem-resistant isolates (positive predictive value [PPV], 78%). Instrument tuning had a significant effect on assay sensitivity, highlighting important factors that must be considered as MALDI-TOF MS moves into applications beyond microbial identification. Using a large

  15. Loop-mediated isothermal amplification assay targeting the blaCTX-M9 gene for detection of extended spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae.

    PubMed

    Thirapanmethee, Krit; Pothisamutyothin, Kanokporn; Nathisuwan, Surakit; Chomnawang, Mullika T; Wiwat, Chanpen

    2014-12-01

    Extended-spectrum β-lactamases (ESBLs) produced by Enterobacteriaceae are one of the resistance mechanisms to most β-lactam antibiotics. ESBLs are currently a major problem in both hospitals and community settings worldwide. Rapid and reliable means of detecting ESBL-producing bacteria is necessary for identification, prevention and treatment. Loop-mediated isothermal amplification (LAMP) is a technique that rapidly amplifies DNA with high specificity and sensitivity under isothermal conditions. This study was aimed to develop a convenient, accurate and inexpensive method for detecting ESBL-producing bacteria by a LAMP technique. ESBLs-producing Escherichia coli and Klebsiella pneumoniae were isolated from a tertiary hospital in Bangkok, Thailand and reconfirmed by double-disk synergy test. A set of four specific oligonucleotide primers of LAMP for detection of bla(CTX-M9) gene was designed based on bla(CTX-M9) from E. coli (GenBank Accession No. AJ416345). The LAMP reaction was amplified under isothermal temperature at 63°C for 60 min. Ladder-like patterns of band sizes from 226 bp of the bla(CTX-M9) DNA target was observed. The LAMP product was further analyzed by restriction digestion with MboI and TaqI endonucleases. The fragments generated were approximately 168, 177 and 250 bp in size for MboI digestion and 165, 193, 229, 281 and 314 bp for TaqI digestion, which is in agreement with the predicted sizes. The sensitivity of the LAMP technique to bla(CTX-M9) was greater than that of the PCR method by at least 10,000-fold. These results showed that the LAMP primers specifically amplified only the bla(CTX-M9) gene. Moreover, the presence of LAMP amplicon was simply determined by adding SYBR Green I in the reaction. In conclusion, this technique for detection of ESBLs is convenient, reliable and easy to perform routinely in hospitals or laboratory units in developing countries. PMID:25284314

  16. bla CTX-M-152, a Novel Variant of CTX-M-group-25, Identified in a Study Performed on the Prevalence of Multidrug Resistance among Natural Inhabitants of River Yamuna, India.

    PubMed

    Azam, Mudsser; Jan, Arif T; Haq, Qazi M R

    2016-01-01

    Natural environment influenced by anthropogenic activities creates selective pressure for acquisition and spread of resistance genes. In this study, we determined the prevalence of Extended Spectrum β-Lactamases producing gram negative bacteria from the River Yamuna, India, and report the identification and characterization of a novel CTX-M gene variant bla CTX-M-152 . Of the total 230 non-duplicate isolates obtained from collected water samples, 40 isolates were found positive for ESBL production through Inhibitor-Potentiation Disc Diffusion test. Based on their resistance profile, 3% were found exhibiting pandrug resistance (PDR), 47% extensively drug resistance (XDR), and remaining 50% showing multidrug resistant (MDR). Following screening and antimicrobial profiling, characterization of ESBLs (bla TEM and bla CTX-M ), and mercury tolerance determinants (merP, merT, and merB) were performed. In addition to abundance of bla TEM-116 (57.5%) and bla CTX-M-15 (37.5%), bacteria were also found to harbor other variants of ESBLs like bla CTX-M-71 (5%), bla CTX-M-3 (7.5%), bla CTX-M-32 (2.5%), bla CTX-M-152 (7.5%), bla CTX-M-55 (2.5%), along with some non-ESBLs; bla TEM-1 (25%) and bla OXY (5%). Additionally, co-occurrence of mercury tolerance genes were observed among 40% of isolates. In silico studies of the new variant, bla CTX-M-152 were conducted through modeling for the generation of structure followed by docking to determine its catalytic profile. CTX-M-152 was found to be an out-member of CTX-M-group-25 due to Q26H, T154A, G89D, P99S, and D146G substitutions. Five residues Ser70, Asn132, Ser237, Gly238, and Arg273 were found responsible for positioning of cefotaxime into the active site through seven H-bonds with binding energy of -7.6 Kcal/mol. Despite small active site, co-operative interactions of Ser237 and Arg276 were found actively contributing to its high catalytic efficiency. To the best of our knowledge, this is the first report of bla CTX-M-152 of CTX

  17. blaCTX-M-152, a Novel Variant of CTX-M-group-25, Identified in a Study Performed on the Prevalence of Multidrug Resistance among Natural Inhabitants of River Yamuna, India

    PubMed Central

    Azam, Mudsser; Jan, Arif T.; Haq, Qazi M. R.

    2016-01-01

    Natural environment influenced by anthropogenic activities creates selective pressure for acquisition and spread of resistance genes. In this study, we determined the prevalence of Extended Spectrum β-Lactamases producing gram negative bacteria from the River Yamuna, India, and report the identification and characterization of a novel CTX-M gene variant blaCTX-M-152. Of the total 230 non-duplicate isolates obtained from collected water samples, 40 isolates were found positive for ESBL production through Inhibitor-Potentiation Disc Diffusion test. Based on their resistance profile, 3% were found exhibiting pandrug resistance (PDR), 47% extensively drug resistance (XDR), and remaining 50% showing multidrug resistant (MDR). Following screening and antimicrobial profiling, characterization of ESBLs (blaTEM and blaCTX-M), and mercury tolerance determinants (merP, merT, and merB) were performed. In addition to abundance of blaTEM-116 (57.5%) and blaCTX-M-15 (37.5%), bacteria were also found to harbor other variants of ESBLs like blaCTX-M-71 (5%), blaCTX-M-3 (7.5%), blaCTX-M-32 (2.5%), blaCTX-M-152 (7.5%), blaCTX-M-55 (2.5%), along with some non-ESBLs; blaTEM-1 (25%) and blaOXY (5%). Additionally, co-occurrence of mercury tolerance genes were observed among 40% of isolates. In silico studies of the new variant, blaCTX-M-152were conducted through modeling for the generation of structure followed by docking to determine its catalytic profile. CTX-M-152 was found to be an out-member of CTX-M-group-25 due to Q26H, T154A, G89D, P99S, and D146G substitutions. Five residues Ser70, Asn132, Ser237, Gly238, and Arg273 were found responsible for positioning of cefotaxime into the active site through seven H-bonds with binding energy of -7.6 Kcal/mol. Despite small active site, co-operative interactions of Ser237 and Arg276 were found actively contributing to its high catalytic efficiency. To the best of our knowledge, this is the first report of blaCTX-M-152 of CTX-M-group-25 from

  18. Eukaryotic origins

    PubMed Central

    Lake, James A.

    2015-01-01

    The origin of the eukaryotes is a fundamental scientific question that for over 30 years has generated a spirited debate between the competing Archaea (or three domains) tree and the eocyte tree. As eukaryotes ourselves, humans have a personal interest in our origins. Eukaryotes contain their defining organelle, the nucleus, after which they are named. They have a complex evolutionary history, over time acquiring multiple organelles, including mitochondria, chloroplasts, smooth and rough endoplasmic reticula, and other organelles all of which may hint at their origins. It is the evolutionary history of the nucleus and their other organelles that have intrigued molecular evolutionists, myself included, for the past 30 years and which continues to hold our interest as increasingly compelling evidence favours the eocyte tree. As with any orthodoxy, it takes time to embrace new concepts and techniques. PMID:26323753

  19. War Wound Treatment Complications Due to Transfer of an IncN Plasmid Harboring blaOXA-181 from Morganella morganii to CTX-M-27-Producing Sequence Type 131 Escherichia coli

    PubMed Central

    Snesrud, Erik; Ong, Ana C.; Appalla, Lakshmi; Koren, Michael; Kwak, Yoon I.; Waterman, Paige E.; Lesho, Emil P.

    2015-01-01

    A 22-year-old male developed a recurrent sacral abscess associated with embedded shrapnel following a blast injury. Cultures grew extended-spectrum β-lactamase (ESBL)-producing, carbapenem-susceptible Escherichia coli. Ertapenem was administered, but the infection recurred after each course of antibiotics. Initial surgical interventions were unsuccessful, and subsequent cultures yielded E. coli and Morganella morganii, both nonsusceptible to carbapenems. The isolates were Carba NP test negative, gave ambiguous results with the modified Hodge test, and amplified the blaOXA48-like gene by real-time PCR. All E. coli isolates were sequence type 131 (ST131), carried nine resistance genes (including blaCTX-M-27) on an IncF plasmid, and were identical by genome sequencing, except for 150 kb of plasmid DNA in carbapenem-nonsusceptible isolates only. Sixty kilobases of this was shared by M. morganii and represented an IncN plasmid harboring blaOXA-181. In M. morganii, the gene was flanked by IS3000 and ISKpn19, but in all but one of the E. coli isolates containing blaOXA-181, a second copy of ISKpn19 had inserted adjacent to IS3000. To the best of our knowledge, this is the first report of blaOXA-181 in the virulent ST131 clonal group and carried by the promiscuous IncN family of plasmids. The tendency of M. morganii to have high MICs of imipenem, a blaOXA-181 substrate profile that includes penicillins but not extended-spectrum cephalosporins, and weak carbapenemase activity almost resulted in the presence of blaOXA-181 being overlooked. We highlight the importance of surveillance for carbapenem resistance in all species, even those with intrinsic resistances, and the value of advanced molecular techniques in detecting subtle genetic changes. PMID:25870058

  20. Original Version

    Cancer.gov

    The EPEC-O (Education in Palliative and End-of-Life Care for Oncology) Self-Study Original Version is a free comprehensive multimedia curricula for health professionals caring for persons with cancer and their families. The curricula is available as an online Self-Study Section and as a CD-ROM you can order.

  1. The IncI1 plasmid carrying the blaCTX-M-1 gene persists in in vitro culture of a Escherichia coli strain from broilers

    PubMed Central

    2014-01-01

    Background Commensal bacteria are a reservoir for antimicrobial-resistance genes. In the Netherlands, bacteria producing Extended Spectrum Beta-Lactamases (ESBL) are found on chicken-meat and in the gut of broilers at a high prevalence and the predominant ESBL-gene is the blaCTX-M-1 located on IncI1 plasmids. We aim to determine the fitness costs of this plasmid for the bacterium. We investigated the conjugation dynamics of IncI1 plasmids carrying the blaCTX-M-1 gene in a batch culture and its impact on the population dynamics of three E. coli populations: donors, recipients and transconjugants. The intrinsic growth rate (ψ), maximum density (K) and lag-phase (λ) of the populations were estimated as well as the conjugation coefficient. Loss of the plasmid by transconjugants was either assumed constant or depended on the effective growth rate of the transconjugants. Parameters were estimated from experiments with pure culture of donors, recipients and transconjugants and with mixed culture of donors and recipients with a duration of 24 or 48 hours. Extrapolation of the results was compared to a 3-months experiment in which a mixed culture of recipient and transconjugant was regularly diluted in new medium. Results No differences in estimated growth parameters (ψ, K or λ) were found between donor, recipient and transconjugant, and plasmid loss was not observed. The conjugation coefficient of transconjugants was 104 times larger than that of the donor. In the 3-months experiment, the proportion of transconjugants did not decrease, indicating no or very small fitness costs. Conclusions In vitro the IncI1 plasmid carrying the blaCTX-M-1 gene imposes no or negligible fitness costs on its E. coli host, and persists without antimicrobial usage. PMID:24666793

  2. Development of a direct ELISA based on carboxy-terminal of penicillin-binding protein BlaR for the detection of β-lactam antibiotics in foods.

    PubMed

    Peng, Juan; Cheng, Guyue; Huang, Lingli; Wang, Yulian; Hao, Haihong; Peng, Dapeng; Liu, Zhenli; Yuan, Zonghui

    2013-11-01

    β-Lactam antibiotics, including penicillins and cephalosporins, are commonly used in veterinary medicine. Illegal use and abuse of β-lactams could cause allergy and selected bacterial resistance. BlaR-CTD, the carboxy-terminal of penicillin-recognizing protein BlaR from Bacillus licheniformis ATCC 14580, was utilized in this study to develop a receptor-based ELISA for detection and determination of β-lactam antibiotics in milk, beef, and chicken. This assay was based on directly competitive inhibition of binding of horseradish peroxidase-labeled ampicillin to the immobilized BlaR-CTD by β-lactams. The assay was developed as screening test with the option as semiquantitative assay, when the identity of a single type of residual β-lactam was known. The IC50 values of 15 β-lactam antibiotics, including benzylpenicillin, ampicillin, amoxicillin, dicloxacillin, oxacillin, nafcillin, cefapirin, cefoperazone, cefalotin, cefazolin, cefquinome, ceftriaxone, cefotaxime, cefalexin, ceftiofur and its metabolite desfuroylceftiofur were evaluated and ranged from 0.18 to 170.81 μg L(-1). Simple sample extraction method was carried out with only phosphate-buffered saline, and the recoveries of selected β-lactam antibiotics in milk, beef, and chicken were in the range of 53.27 to 128.29 %, most ranging from 60 to 120 %. The inter-assay variability was below 30 %. Limits of detection in milk, beef, and chicken muscles with cefquinome matrix calibration were 2.10, 30.68, and 31.13 μg kg(-1), respectively. This study firstly established a rapid, simple, and accurate method for simultaneous detection of 15 β-lactams in edible tissues, among which 11 β-lactams controlled by European Union could be detected below maximum residue limits. PMID:24013636

  3. blaVIM-2 Cassette-Containing Novel Integrons in Metallo-β-Lactamase-Producing Pseudomonas aeruginosa and Pseudomonas putida Isolates Disseminated in a Korean Hospital

    PubMed Central

    Lee, Kyungwon; Lim, Jong Back; Yum, Jong Hwa; Yong, Dongeun; Chong, Yunsop; Kim, June Myung; Livermore, David M.

    2002-01-01

    We investigated the phenotypic and genetic properties of metallo-β-lactamase-producing Pseudomonas isolates collected at a tertiary-care hospital in Korea since 1995. The prevalence of imipenem resistance among Pseudomonas aeruginosa isolates reached 16% in 1997, when 9% of the resistant organisms were found to produce VIM-2 β-lactamase, a class B enzyme previously found only in P. aeruginosa isolates from Europe. VIM-2-producing isolates of Pseudomonas putida were also detected. Resistance was transferable from both these species to P. aeruginosa PAO4089Rp by filter mating, although the resistance determinant could not be found on any detectable plasmid. Serotyping showed that many of the VIM-2-producing P. aeruginosa isolates belonged to serotypes O:11 and O:12, and pulsed-field gel electrophoresis of XbaI-digested genomic DNA revealed that many had identical profiles, whereas the P. putida isolates were diverse. Sequencing showed that the blaVIM-2 genes resided as cassettes in class 1 integrons. In contrast to previous VIM-encoding integrons, the integron sequenced from a P. aeruginosa isolate had blaVIM located downstream of a variant of aacA4. blaVIM also lay in a class 1 integron in a representative P. putida strain, but the organization of this integron was different from that sequenced from the P. aeruginosa strain. In conclusion, the metallo-β-lactamase produced by these imipenem-resistant Pseudomonas isolates was VIM-2, and the accumulation of producers reflected clonal dissemination as well as horizontal spread. Strict measures are required in order to control a further spread of resistance. PMID:11897589

  4. Extensively Drug-Resistant Pseudomonas aeruginosa Isolates Containing blaVIM-2 and Elements of Salmonella Genomic Island 2: a New Genetic Resistance Determinant in Northeast Ohio

    PubMed Central

    Perez, Federico; Hujer, Andrea M.; Marshall, Steven H.; Ray, Amy J.; Rather, Philip N.; Suwantarat, Nuntra; Dumford, Donald; O'Shea, Patrick; Domitrovic, T. Nicholas J.; Salata, Robert A.; Chavda, Kalyan D.; Chen, Liang; Kreiswirth, Barry N.; Vila, Alejandro J.; Haussler, Susanne; Jacobs, Michael R.

    2014-01-01

    Carbapenems are a mainstay of treatment for infections caused by Pseudomonas aeruginosa. Carbapenem resistance mediated by metallo-β-lactamases (MBLs) remains uncommon in the United States, despite the worldwide emergence of this group of enzymes. Between March 2012 and May 2013, we detected MBL-producing P. aeruginosa in a university-affiliated health care system in northeast Ohio. We examined the clinical characteristics and outcomes of patients, defined the resistance determinants and structure of the genetic element harboring the blaMBL gene through genome sequencing, and typed MBL-producing P. aeruginosa isolates using pulsed-field gel electrophoresis (PFGE), repetitive sequence-based PCR (rep-PCR), and multilocus sequence typing (MLST). Seven patients were affected that were hospitalized at three community hospitals, a long-term-care facility, and a tertiary care center; one of the patients died as a result of infection. Isolates belonged to sequence type 233 (ST233) and were extensively drug resistant (XDR), including resistance to all fluoroquinolones, aminoglycosides, and β-lactams; two isolates were nonsusceptible to colistin. The blaMBL gene was identified as blaVIM-2 contained within a class 1 integron (In559), similar to the cassette array previously detected in isolates from Norway, Russia, Taiwan, and Chicago, IL. Genomic sequencing and assembly revealed that In559 was part of a novel 35-kb region that also included a Tn501-like transposon and Salmonella genomic island 2 (SGI2)-homologous sequences. This analysis of XDR strains producing VIM-2 from northeast Ohio revealed a novel recombination event between Salmonella and P. aeruginosa, heralding a new antibiotic resistance threat in this region's health care system. PMID:25070102

  5. Draft Genome Sequences of Acinetobacter baumannii Strains Harboring the blaNDM-1 Gene Isolated in Lebanon from Civilians Wounded during the Syrian Civil War

    PubMed Central

    Eisen, Jonathan A.; Jospin, Guillaume; Hamze, Monzer; Rafei, Rayane; Salloum, Tamara; Ibrahim, Joe; Coil, David A.

    2016-01-01

    We present here the draft genome sequences of multidrug-resistant blaNDM-1-positive Acinetobacter baumannii strains ACMH-6200 and ACMH-6201, isolated in north Lebanon from civilians wounded during the Syrian civil war. The draft genomes were contained in 217 contigs for ACMH-6200 and 83 contigs for ACMH-6201, including a combined 3,997,237 bases for ACMH-6200 and 3,983,110 bases for ACMH-6201, with 39% and 38.9% G+C content, respectively. PMID:26823599

  6. Draft Genome Sequences of Acinetobacter baumannii Strains Harboring the blaNDM-1 Gene Isolated in Lebanon from Civilians Wounded during the Syrian Civil War.

    PubMed

    Tokajian, Sima; Eisen, Jonathan A; Jospin, Guillaume; Hamze, Monzer; Rafei, Rayane; Salloum, Tamara; Ibrahim, Joe; Coil, David A

    2016-01-01

    We present here the draft genome sequences of multidrug-resistant blaNDM-1-positive Acinetobacter baumannii strains ACMH-6200 and ACMH-6201, isolated in north Lebanon from civilians wounded during the Syrian civil war. The draft genomes were contained in 217 contigs for ACMH-6200 and 83 contigs for ACMH-6201, including a combined 3,997,237 bases for ACMH-6200 and 3,983,110 bases for ACMH-6201, with 39% and 38.9% G+C content, respectively. PMID:26823599

  7. Role of OXA-23 and AdeABC efflux pump for acquiring carbapenem resistance in an Acinetobacter baumannii strain carrying the blaOXA-66 gene.

    PubMed

    Lee, Yangsoon; Yum, Jong Hwa; Kim, Chang-Ki; Yong, Dongeun; Jeon, Eun Hee; Jeong, Seok Hoon; Ahn, Jee Young; Lee, Kyungwon

    2010-01-01

    This study was performed to determine the mechanisms for acquiring carbapenem resistance in six clinical isolates of Acinetobacter baumannii. All isolates showed similar SmaI-macrorestriction patterns with less than 3 band differences by PFGE. The isolates showed a high level resistance (>32 mg/L) to both imipenem and meropenem by Etest. Phe-Arg-beta-naphthylamide lowered the MICs of carbapenems. Real-time PCR experiments showed that expression levels of the adeB gene in the six A. baumannii isolates were 10- to 40-times higher than those of imipenem-susceptible strains. Direct sequencing of PCR products showed that all isolates carried the bla(OXA-23) gene, which was preceded by ISAba1. The bla(OXA-23) probe hybridized with approximately 500-kb I-CeuI chromosomal fragments, but not with a plasmid. These findings suggest that overexpression of the AdeABC efflux pump as well as chromosome-borne OXA-23 may play a role in acquiring carbapenem resistance in our A. baumannii isolates. PMID:20124329

  8. The first report of detecting the blaSIM-2 gene and determining the complete sequence of the SIM-encoding plasmid.

    PubMed

    Sun, F; Zhou, D; Wang, Q; Feng, J; Feng, W; Luo, W; Zhang, D; Liu, Y; Qiu, X; Yin, Z; Chen, W; Xia, P

    2016-04-01

    An imipenem-resistant Pseudomonas aeruginosa strain HN39 that harbours a blaSIM-2-carrying plasmid pHN39-SIM, was isolated from a patient with craniocerebral infections in China. The SIM-2 protein differs from SIM-1 by a single amino acid substitution Gly198Asp. pHN39-SIM is a novel 282-kb megaplasmid and it possesses the replication and partition systems of an unknown incompatibility group. pHN39-SIM carries a total of ten separate accessory modules especially including a novel 38.8-kb multidrug resistance region. In addition to the known transposable elements ISPst3, a Tn5563a remnant, IS1071, Tn5046, ΔTn4662a and ΔTn512, harboured in these accessory modules are six novel ones ISPa59 to ISPa62, In1208 and Tn6284. The multidrug resistance region is composed of Tn6284 generated from the insertion of an In4-family integron In1208 into Tn5046, and a Tn4662a-derived element with the insertion of ΔTn512 connected with two other genes. In1208 carries not only blaSIM-2 but several additional genes accounting for resistance to erythromycin, chloramphenicol, rifampicin, streptomycin, quaternary ammonium compounds, sulphonamides and mercury. PMID:26706613

  9. MALDI-TOF Mass Spectrometry for Multilocus Sequence Typing of Escherichia coli Reveals Diversity among Isolates Carrying blaCMY₋₂-Like Genes.

    PubMed

    Tagg, Kaitlin A; Ginn, Andrew N; Partridge, Sally R; Iredell, Jonathan R

    2015-01-01

    Effective surveillance and management of pathogenic Escherichia coli relies on robust and reproducible typing methods such as multilocus sequence typing (MLST). Typing of E. coli by MLST enables tracking of pathogenic clones that are known to carry virulence factors or spread resistance, such as the globally-prevalent ST131 lineage. Standard MLST for E. coli requires sequencing of seven alleles, or a whole genome, and can take several days. Here, we have developed and validated a nucleic-acid-based MALDI-TOF mass spectrometry (MS) method for MLST as a rapid alternative to sequencing that requires minimal operator expertise. Identification of alleles was 99.6% concordant with sequencing. We employed MLST by MALDI-TOF MS to investigate diversity among 62 E. coli isolates from Sydney, Australia, carrying a blaCMY-2-like gene on an IncI1 plasmid to determine whether any dominant clonal lineages are associated with the spread of this globally-disseminated resistance gene. Thirty-four known sequence types were identified, including lineages associated with human disease, animal and environmental sources. This suggests that the dissemination of blaCMY-2-like-genes is more complex than the simple spread of successful pathogenic clones. E. coli MLST by MALDI-TOF MS, employed here for the first time, can be utilised as an automated tool for large-scale population analyses or for targeted screening for known high-risk clones in a diagnostic setting. PMID:26588228

  10. MALDI-TOF Mass Spectrometry for Multilocus Sequence Typing of Escherichia coli Reveals Diversity among Isolates Carrying blaCMY-2-Like Genes

    PubMed Central

    Tagg, Kaitlin A.; Ginn, Andrew N.; Partridge, Sally R.; Iredell, Jonathan R.

    2015-01-01

    Effective surveillance and management of pathogenic Escherichia coli relies on robust and reproducible typing methods such as multilocus sequence typing (MLST). Typing of E. coli by MLST enables tracking of pathogenic clones that are known to carry virulence factors or spread resistance, such as the globally-prevalent ST131 lineage. Standard MLST for E. coli requires sequencing of seven alleles, or a whole genome, and can take several days. Here, we have developed and validated a nucleic-acid-based MALDI-TOF mass spectrometry (MS) method for MLST as a rapid alternative to sequencing that requires minimal operator expertise. Identification of alleles was 99.6% concordant with sequencing. We employed MLST by MALDI-TOF MS to investigate diversity among 62 E. coli isolates from Sydney, Australia, carrying a blaCMY-2-like gene on an IncI1 plasmid to determine whether any dominant clonal lineages are associated with the spread of this globally-disseminated resistance gene. Thirty-four known sequence types were identified, including lineages associated with human disease, animal and environmental sources. This suggests that the dissemination of blaCMY-2-like-genes is more complex than the simple spread of successful pathogenic clones. E. coli MLST by MALDI-TOF MS, employed here for the first time, can be utilised as an automated tool for large-scale population analyses or for targeted screening for known high-risk clones in a diagnostic setting. PMID:26588228

  11. Colistin- and Carbapenem-Resistant Escherichia coli Harboring mcr-1 and blaNDM-5, Causing a Complicated Urinary Tract Infection in a Patient from the United States

    PubMed Central

    Mediavilla, José R.; Patrawalla, Amee; Chen, Liang; Chavda, Kalyan D.; Mathema, Barun; Vinnard, Christopher; Dever, Lisa L.

    2016-01-01

    ABSTRACT Colistin is increasingly used as an antibiotic of last resort for the treatment of carbapenem-resistant Gram-negative infections. The plasmid-borne colistin resistance gene mcr-1 was initially identified in animal and clinical samples from China and subsequently reported worldwide, including in the United States. Of particular concern is the spread of mcr-1 into carbapenem-resistant bacteria, thereby creating strains that approach pan-resistance. While several reports of mcr-1 have involved carbapenem-resistant strains, no such isolates have been described in the United States. Here, we report the isolation and identification of an Escherichia coli strain harboring both mcr-1 and carbapenemase gene blaNDM-5 from a urine sample in a patient without recent travel outside the United States. The isolate exhibited resistance to both colistin and carbapenems, but was susceptible to amikacin, aztreonam, gentamicin, nitrofurantoin, tigecycline, and trimethoprim-sulfamethoxazole. The mcr-1- and blaNDM-5-harboring plasmids were completely sequenced and shown to be highly similar to plasmids previously reported from China. The strain in this report was first isolated in August 2014, highlighting an earlier presence of mcr-1 within the United States than previously recognized. PMID:27578755

  12. Antibiotic-Resistant Klebsiella pneumoniae and Escherichia coli High-Risk Clones and an IncFIIk Mosaic Plasmid Hosting Tn1 (blaTEM-4) in Isolates from 1990 to 2004

    PubMed Central

    Rodríguez, Irene; Novais, Ângela; Lira, Felipe; Valverde, Aránzazu; Curião, Tânia; Martínez, José Luis; Baquero, Fernando; Cantón, Rafael

    2015-01-01

    We describe the genetic background of blaTEM-4 and the complete sequence of pRYC11::blaTEM-4, a mosaic plasmid that is highly similar to pKpQIL-like variants, predominant among TEM-4 producers in a Spanish hospital (1990 to 2004), which belong to Klebsiella pneumoniae and Escherichia coli high-risk clones responsible for the current spread of different antibiotic resistance genes. Predominant populations of plasmids and host adapted clonal lineages seem to have greatly contributed to the spread of resistance to extended-spectrum cephalosporins. PMID:25691645

  13. In71, an Enterobacter cloacae blaVIM-1-carrying integron related to In70.2 from Italian Pseudomonas aeruginosa isolates: a SENTRY Antimicrobial Surveillance Program report.

    PubMed

    Castanheira, Mariana; Sader, Hélio S; Jones, Ronald N; Debbia, Eugenio; Picão, Renata C; Gales, Ana C

    2007-01-01

    An Enterobacter cloacae strain showing decreased susceptibility to carbapenems was isolated from a blood culture of a patient hospitalized in Genoa, Italy, and screened for the presence of metallo-beta-lactamase (MBL) genes as part of the SENTRY Antimicrobial Surveillance Program. A bla(VIM-1)-carrying integron named In71 nearly identical to In70.2 reported in Pseudomonas aeruginosa strains isolated from various Italian cities since 2001 was identified in this strain. Interestingly, the In71 did not carry aadA1 nor possess the ISPa7 usually found in the P. aeruginosa integron In70.2. Mobilization of MBL genes from P. aeruginosa to members of the Enterobacteriaceae family is very worrisome because the rapid and wide dissemination of these potent antimicrobial resistance mechanisms could jeopardize the clinical use of carbapenems for the treatment of multidrug-resistant Enterobacteriaceae infections. PMID:17650966

  14. OXA-46, a new class D beta-lactamase of narrow substrate specificity encoded by a blaVIM-1-containing integron from a Pseudomonas aeruginosa clinical isolate.

    PubMed

    Giuliani, Francesco; Docquier, Jean-Denis; Riccio, Maria Letizia; Pagani, Laura; Rossolini, Gian Maria

    2005-05-01

    A novel OXA-type enzyme, named OXA-46, was found to be encoded by a gene cassette inserted into a class 1 integron from a multidrug-resistant Pseudomonas aeruginosa clinical isolate. The variable region of the integron also contained a bla(VIM-1) metallo-beta-lactamase cassette and a duplicated aacA4 aminoglycoside acetyltransferase cassette. OXA-46 belongs to the OXA-2 lineage of class D beta-lactamases. It exhibits 78% sequence identity with OXA-2 and the highest similarity (around 92% identity) with another OXA-type enzyme detected in clinical isolates of Burkholderia cepacia and in unidentified bacteria from a wastewater plant. Expression of bla(OXA-46) in Escherichia coli decreased susceptibility to penicillins and narrow-spectrum cephalosporins but not to extended-spectrum cephalosporins, cefsulodin, aztreonam, or carbapenems. The enzyme was overproduced in E. coli and purified by two anion-exchange chromatography steps (approximate yield, 6 mg/liter). OXA-46 was made of a 28.5-kDa polypeptide and exhibited an alkaline pI (7.8). In its native form OXA-46 appeared to be dimeric, and the oligomerization state was not affected by EDTA. Kinetic analysis of OXA-46 revealed a specificity for narrow-spectrum substrates, including oxacillin, other penicillins (but not temocillin), and narrow-spectrum cephalosporins. The enzyme apparently did not interact with temocillin, oxyimino-cephalosporins, or aztreonam. OXA-46 was inactivated by tazobactam and carbapenems and, although less efficiently, also by clavulanic acid. Enzyme activity was not affected either by EDTA or by divalent cations and exhibited low susceptibility to NaCl. These findings underscore the functional and structural diversity that can be encountered among class D beta-lactamases. PMID:15855521

  15. Interspecies Dissemination of a Mobilizable Plasmid Harboring blaIMP-19 and the Possibility of Horizontal Gene Transfer in a Single Patient.

    PubMed

    Yamamoto, Masaki; Matsumura, Yasufumi; Gomi, Ryota; Matsuda, Tomonari; Tanaka, Michio; Nagao, Miki; Takakura, Shunji; Uemoto, Shinji; Ichiyama, Satoshi

    2016-09-01

    Carbapenemase-producing Gram-negative bacilli have been a global concern over the past 2 decades because these organisms can cause severe infections with high mortality rates. Carbapenemase genes are often carried by mobile genetic elements, and resistance plasmids can be transferred through conjugation. We conducted whole-genome sequencing (WGS) to demonstrate that the same plasmid harboring a metallo-β-lactamase gene was detected in two different species isolated from a single patient. Metallo-β-lactamase-producing Achromobacter xylosoxidans (KUN4507), non-metallo-β-lactamase-producing Klebsiella pneumoniae (KUN4843), and metallo-β-lactamase-producing K. pneumoniae (KUN5033) were sequentially isolated from a single patient and then analyzed in this study. Antimicrobial susceptibility testing, molecular typing (pulsed-field gel electrophoresis and multilocus sequence typing), and conjugation analyses were performed by conventional methods. Phylogenetic and molecular clock analysis of K. pneumoniae isolates were performed with WGS, and the nucleotide sequences of plasmids detected from these isolates were determined using WGS. Conventional molecular typing revealed that KUN4843 and KUN5033 were identical, whereas the phylogenetic tree analysis revealed a slight difference. These two isolates were separated from the most recent common ancestor 0.74 years before they were isolated. The same resistance plasmid harboring blaIMP-19 was detected in metallo-β-lactamase-producing A. xylosoxidans and K. pneumoniae Although this plasmid was not self-transferable, the conjugation of this plasmid from A. xylosoxidans to non-metallo-β-lactamase-producing K. pneumoniae was successfully performed. The susceptibility patterns for metallo-β-lactamase-producing K. pneumoniae and the transconjugant were similar. These findings supported the possibility of the horizontal transfer of plasmid-borne blaIMP-19 from A. xylosoxidans to K. pneumoniae in a single patient. PMID:27381397

  16. Complete Sequence of the FII Plasmid p42-2, Carrying blaCTX-M-55, oqxAB, fosA3, and floR from Escherichia coli.

    PubMed

    Yang, Qiu E; Walsh, Timothy Rutland; Liu, Bao Tao; Zou, Meng Ting; Deng, Hui; Fang, Liang Xing; Liao, Xiao Ping; Sun, Jian; Liu, Ya Hong

    2016-07-01

    We sequenced a novel conjugative multidrug resistance IncF plasmid, p42-2, isolated from Escherichia coli strain 42-2, previously identified in China. p42-2 is 106,886 bp long, composed of a typical IncFII-type backbone (∼54 kb) and one distinct acquired DNA region spanning ∼53 kb, harboring 12 antibiotic resistance genes [blaCTX-M-55, oqxA, oqxB, fosA3, floR, tetA(A), tetA(R), strA, strB, sul2, aph(3')-II, and ΔblaTEM-1]. The spread of these multidrug resistance determinants on the same plasmid is of great concern and, because of coresistance to antibiotics from different classes, is therapeutically challenging. PMID:27067314

  17. New Delhi Metallo-β-Lactamase-Mediated Carbapenem Resistance: Origin, Diagnosis, Treatment and Public Health Concern

    PubMed Central

    Wei, Wen-Juan; Yang, Hai-Fei; Ye, Ying; Li, Jia-Bin

    2015-01-01

    Objective: To review the origin, diagnosis, treatment and public health concern of New Delhi metallo-β-lactamase (NDM)-producing bacteria. Data Sources: We searched database for studies published in English. The database of PubMed from 2007 to 2015 was used to conduct a search using the keyword term “NDM and Acinetobacter or Enterobacteriaceae or Pseudomonas aeruginosa.” Study Selection: We collected data including the relevant articles on international transmission, testing methods and treatment strategies of NDM-positive bacteria. Worldwide NDM cases were reviewed based on 22 case reports. Results: The first documented case of infection caused by bacteria producing NDM-1 occurred in India, in 2008. Since then, 13 blaNDM variants have been reported. The rise of NDM is not only due to its high rate of genetic transfer among unrelated bacterial species, but also to human factors such as travel, sanitation and food production and preparation. With limited treatment options, scientists try to improve available therapies and create new ones. Conclusions: In order to slow down the spread of these NDM-positive bacteria, a series of measures must be implemented. The creation and transmission of blaNDM are potentially global health issues, which are not issues for one country or one medical community, but for global priorities in general and for individual wound care practitioners specifically. PMID:26168840

  18. Successful international clones of blaCTX-M-15-producing Klebsiella pneumoniae with coexpression of plasmid-mediated quinolone resistance (PMQR) determinants in Tehran hospitals.

    PubMed

    Nematzadeh, Shoeib; Shahcheraghi, Fereshteh; Iversen, Aina; Giske, Christian G

    2015-12-01

    The dissemination of plasmid-mediated multidrug resistance in Enterobacteriaceae is a major public health concern. We investigated the prevalence of plasmid-mediated quinolone resistance (PMQR), 16S rRNA methylases, CTX-M, and acquired AmpC enzymes in ESBL-producing Klebsiella pneumoniae (n=40) from Tehran hospitals. Plasmid replicon typing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) were carried out for typing. CTX-M group 1 (confirmed as bla(CTX-M-15) in selected isolates) was found in 35/40 isolates. Thirty-two isolates hosted PMQR genes. Twenty isolates featured aac(6')-Ib-CR only; 9 isolates had aac(6')-Ib-CR and qnrB; 2 isolates had aac(6')-Ib-CR and qnrS; and 1 isolate had aac(6')-Ib-CR, qnrS, and qepA. The 16S rRNA methylase RmtB was found in 1 isolate; and acquired AmpC enzymes, in 6 isolates. PFGE detected 7 pulsotypes, the largest corresponded to sequence type 16. The successful clone ST101 was also found. The emergence of successful clones of K. pneumoniae in Tehran hospitals is concerning. PMID:26458278

  19. Molecular Characterization of Escherichia coli Strains Isolated from Retail Meat That Harbor blaCTX-M and fosA3 Genes.

    PubMed

    Xie, Miaomiao; Lin, Dachuan; Chen, Kaichao; Chan, Edward Wai Chi; Yao, Wen; Chen, Sheng

    2016-04-01

    A total of 55 cefotaxime-resistantEscherichia coliisolates were obtained from retail meat products purchased in Shenzhen, China, during the period November 2012 to May 2013. Thirty-seven of these 55 isolates were found to harbor ablaCTX-Mgene, with theblaCTX-M-1group being the most common type.blaCMY-2was detected in 16 isolates, alone or in combination with other extended-spectrum β-lactamase (ESBL) determinants. Importantly, thefosA3gene, which encodes fosfomycin resistance, was detected in 12 isolates, with several being found to reside in the conjugative plasmid that harbored theblaCTX-Mgene. The insertion sequence IS26was observed upstream of some of theblaCTX-M-55andfosA3genes. Conjugation experiments showed thatblaCTX-Mgenes from 15 isolates were transferrable, with Inc I1 and Inc FII being the most prevalent replicons. High clonal diversity was observed among theblaCTX-Mproducers, suggesting that horizontal transfer of theblaCTX-Mgenes amongE. colistrains in retail meats is a common event and that such strains may constitute an important reservoir ofblaCTX-Mgenes, which may be readily disseminated to other potential human pathogens. PMID:26856843

  20. Mosaic structure of p1658/97, a 125-kilobase plasmid harboring an active amplicon with the extended-spectrum beta-lactamase gene blaSHV-5.

    PubMed

    Zienkiewicz, M; Kern-Zdanowicz, I; Gołebiewski, M; Zyliñska, J; Mieczkowski, P; Gniadkowski, M; Bardowski, J; Cegłowski, P

    2007-04-01

    Escherichia coli isolates recovered from patients during a clonal outbreak in a Warsaw, Poland, hospital in 1997 produced different levels of an extended-spectrum beta-lactamase (ESBL) of the SHV type. The beta-lactamase hyperproduction correlated with the multiplication of ESBL gene copies within a plasmid. Here, we present the complete nucleotide sequence of plasmid p1658/97 carried by the isolates recovered during the outbreak. The plasmid is 125,491 bp and shows a mosaic structure in which all modules constituting the plasmid core are homologous to those found in plasmids F and R100 and are separated by segments of homology to other known regions (plasmid R64, Providencia rettgeri genomic island R391, Vibrio cholerae STX transposon, Klebsiella pneumoniae or E. coli chromosomes). Plasmid p1658/97 bears two replication systems, IncFII and IncFIB; we demonstrated that both are active in E. coli. The presence of an active partition system (sopABC locus) and two postsegregational killing systems (pemIK and hok/sok) indicates that the plasmid should be stably maintained in E. coli populations. The conjugative transfer is ensured by the operons of the tra and trb genes. We also demonstrate that the plasmidic segment undergoing amplification contains the blaSHV-5 gene and is homologous to a 7.9-kb fragment of the K. pneumoniae chromosome. The amplicon displays the structure of a composite transposon of type I. PMID:17220406

  1. Absence of co-localization between pathovar-associated virulence factors and extended-spectrum β-lactamase (blaCTX-M) genes on a single plasmid.

    PubMed

    Valat, Charlotte; Forest, Karine; Billet, Méganne; Polizzi, Charlène; Saras, Estelle; Madec, Jean-Yves; Haenni, Marisa

    2016-08-30

    Extended-spectrum β-lactamases (ESBLs) were reported in virulent food-borne Escherichia coli clones, and numerous genes encoding ESBLs and virulence factors (VFs) are plasmid-mediated. We investigated the plasmidic co-localization of ESBL genes and pathovar-associated VF genes isolated in 18 E. coli isolates from faecal samples of diseased cattle. From the rare ESBL-producing E. coli among the various pathovars, no plasmid co-localization was found between VF and blaCTX-M genes on a single plasmid. However, a link between replicon types and VFs was highlighted: EspP was associated with IncFIB and ToxB with IncB/O. Associations of IncF alleles to VF or CTX-M-types were also identified: CS31A was linked to the allele FIB38 and CTX-M-14 to IncFII2. Also, as illustrated here, IncFII and IncFIB were carried by two different plasmids in a single cell. PMID:27527778

  2. Full-Genome Sequence of Escherichia coli K-15KW01, a Uropathogenic E. coli B2 Sequence Type 127 Isolate Harboring a Chromosomally Carried blaCTX-M-15 Gene.

    PubMed

    Zurfluh, Katrin; Tasara, Taurai; Stephan, Roger

    2016-01-01

    We present here the full-genome sequence of Escherichia coli K-15KW01, an extended-spectrum-β-lactamase-producing uropathogenic strain. Assembly and annotation of the draft genome resulted in a 5,154,641-bp chromosome and revealed a chromosomally contained blaCTX-M-15 gene embedded at the right-hand extremity of an ISEcp1 element in a plasmid-like structure (36,907 bp). PMID:27587831

  3. Full-Genome Sequence of Escherichia coli K-15KW01, a Uropathogenic E. coli B2 Sequence Type 127 Isolate Harboring a Chromosomally Carried blaCTX-M-15 Gene

    PubMed Central

    Zurfluh, Katrin; Tasara, Taurai

    2016-01-01

    We present here the full-genome sequence of Escherichia coli K-15KW01, an extended-spectrum-β-lactamase-producing uropathogenic strain. Assembly and annotation of the draft genome resulted in a 5,154,641-bp chromosome and revealed a chromosomally contained blaCTX-M-15 gene embedded at the right-hand extremity of an ISEcp1 element in a plasmid-like structure (36,907 bp). PMID:27587831

  4. Complete Genome Sequence of a Human-Invasive Salmonella enterica Serovar Typhimurium Strain of the Emerging Sequence Type 213 Harboring a Multidrug Resistance IncA/C Plasmid and a blaCMY-2-Carrying IncF Plasmid

    PubMed Central

    Calva, Edmundo; Calva, Juan J.; Wiesner, Magdalena; Fernández-Mora, Marcos; Puente, José L.

    2015-01-01

    Salmonella enterica subsp. enterica serovar Typhimurium strain 33676 was isolated in Mexico City, Mexico, from a patient with a systemic infection, and its complete genome sequence was determined using PacBio single-molecule real-time technology. Strain 33676 harbors an IncF plasmid carrying the extended-spectrum cephalosporin gene blaCMY-2 and a multidrug resistance IncA/C plasmid. PMID:26564044

  5. Analysis of the beta-lactamase plasmid of borderline methicillin-susceptible Staphylococcus aureus: focus on bla complex genes and cadmium resistance determinants cadD and cadX.

    PubMed

    Massidda, Orietta; Mingoia, Marina; Fadda, Daniela; Whalen, Michael B; Montanari, Maria Pia; Varaldo, Pietro E

    2006-03-01

    Borderline methicillin-susceptible Staphylococcus aureus strains are a rather homogeneous group, characterized by MICs of penicillinase-resistant penicillins (PRPs) at or just below the susceptibility breakpoint. Other features unique to this group include the presence of a pBW15-like beta-lactamase plasmid, the association with phage complex 94/96, and the production of a PRP-hydrolyzing beta-lactamase activity in addition to the classical penicillinase activity. The four HindIII fragments of pBORa53, a pBW15-like plasmid from the well-studied borderline S. aureus strain a53, were cloned in Escherichia coli, sequenced and analyzed. The plasmid (17,334 bp in size) contains 14 open reading frames (ORFs) and a complete copy of transposon Tn552, which harbors the three genes of the bla complex (blaZ, blaR1, and blaI) necessary for penicillinase production. Among the other 11 ORFs identified, two were homologous to cadmium resistance determinants of Staphylococcus lugdunensis and to the cadD and cadX genes recently detected in S. aureus. Consistent with this, strain a53 was found to be cadmium resistant. From a collection of 30 S. aureus isolates with borderline PRP MIC levels, 27 matched strain a53 in the positive amplification reactions with all of the four primer pairs targeting the cadD-cadX region, the presence of the 17.3-kb plasmid, and the level of cadmium resistance. The well-established S. aureus laboratory strain ATCC 29213 was also found to express cadD-cadX-mediated cadmium resistance. pBORa53 could be re-isolated from transformants obtained by transferring it into a PRP-susceptible recipient. However, while the transformants demonstrated levels of cadmium and penicillin resistance similar to those of strain a53, they remained fully susceptible to PRPs. PMID:16229889

  6. Occurrence of blaCTX-M-1, qnrB1 and virulence genes in avian ESBL-producing Escherichia coli isolates from Tunisia

    PubMed Central

    Kilani, Hajer; Abbassi, Mohamed Salah; Ferjani, Sana; Mansouri, Riadh; Sghaier, Senda; Ben Salem, Rakia; Jaouani, Imen; Douja, Gtari; Brahim, Sana; Hammami, Salah; Ben Chehida, Noureddine; Boubaker, Ilhem Boutiba-Ben

    2015-01-01

    Avian ESBL-producing Escherichia coli isolates have been increasingly reported worldwide. Animal to human dissemination, via food chain or direct contact, of these resistant bacteria has been reported. In Tunisia, little is known about avian ESBL- producing E. coli and further studies are needed. Seventeen ESBL-producing Escherichia coli isolates from poultry feces from two farms (Farm 1 and farm 2) in the North of Tunisia have been used in this study. Eleven of these isolates (from farm 1) have the same resistance profile to nalidixic acid, sulfonamides, streptomycin, tetracycline, and norfloxacine (intermediately resistant). Out of the six isolates recovered from farm 2, only one was co-resistant to tetracycline. All isolates, except one, harbored blaCTX-M-1 gene, and one strain co-harbored the blaTEM-1 gene. The genes tetA and tetB were carried, respectively, by 11 and 1 amongst the 12 tetracycline-resistant isolates. Sulfonamides resistance was encoded by sul1, sul2, and sul3 genes in 3, 17, and 5 isolates, respectively. The qnrB1 was detected in nine strains, one of which co-harbored qnrS1 gene. The search for the class 1 and 2 integrons by PCR showed that in farm 1, class 1 and 2 integrons were found in one and ten isolates, respectively. In farm 2, class 1 integron was found in only one isolate, class 2 was not detected. Only one gene cassette arrangement was demonstrated in the variable regions (VR) of the 10 int2-positive isolates: dfrA1- sat2-aadA1. The size of the VR of the class 1 integron was approximately 250 bp in one int1-positive isolate, whereas in the second isolate, no amplification was observed. All isolates of farm 1 belong to the phylogroup A (sub-group A0). However, different types of phylogroups in farm 2 were detected. Each of the phylogroups A1, B22, B23 was detected in one strain, while the D2 phylogroup was found in 3 isolates. The virulence genes iutA, fimH, and traT were detected in 3, 7, and 3 isolates, respectively. Two types of

  7. Novel blaROB-1-bearing plasmid conferring resistance to β-lactams in Haemophilus parasuis isolates from healthy weaning pigs.

    PubMed

    Moleres, Javier; Santos-López, Alfonso; Lázaro, Isidro; Labairu, Javier; Prat, Cristina; Ardanuy, Carmen; González-Zorn, Bruno; Aragon, Virginia; Garmendia, Junkal

    2015-05-01

    Haemophilus parasuis, the causative agent of Glässer's disease, is one of the early colonizers of the nasal mucosa of piglets. It is prevalent in swine herds, and lesions associated with disease are fibrinous polyserositis and bronchopneumonia. Antibiotics are commonly used in disease control, and resistance to several antibiotics has been described in H. parasuis. Prediction of H. parasuis virulence is currently limited by our scarce understanding of its pathogenicity. Some genes have been associated with H. parasuis virulence, such as lsgB and group 1 vtaA, while biofilm growth has been associated with nonvirulent strains. In this study, 86 H. parasuis nasal isolates from farms that had not had a case of disease for more than 10 years were obtained by sampling piglets at weaning. Isolates were studied by enterobacterial repetitive intergenic consensus PCR and determination of the presence of lsgB and group 1 vtaA, biofilm formation, inflammatory cell response, and resistance to antibiotics. As part of the diversity encountered, a novel 2,661-bp plasmid, named pJMA-1, bearing the blaROB-1 β-lactamase was detected in eight colonizing strains. pJMA-1 was shown to share a backbone with other small plasmids described in the Pasteurellaceae, to be 100% stable, and to have a lower biological cost than the previously described plasmid pB1000. pJMA-1 was also found in nine H. parasuis nasal strains from a separate collection, but it was not detected in isolates from the lesions of animals with Glässer's disease or in nontypeable Haemophilus influenzae isolates. Altogether, we show that commensal H. parasuis isolates represent a reservoir of β-lactam resistance genes which can be transferred to pathogens or other bacteria. PMID:25747001

  8. Novel blaROB-1-Bearing Plasmid Conferring Resistance to β-Lactams in Haemophilus parasuis Isolates from Healthy Weaning Pigs

    PubMed Central

    Moleres, Javier; Santos-López, Alfonso; Lázaro, Isidro; Labairu, Javier; Prat, Cristina; Ardanuy, Carmen; González-Zorn, Bruno

    2015-01-01

    Haemophilus parasuis, the causative agent of Glässer's disease, is one of the early colonizers of the nasal mucosa of piglets. It is prevalent in swine herds, and lesions associated with disease are fibrinous polyserositis and bronchopneumonia. Antibiotics are commonly used in disease control, and resistance to several antibiotics has been described in H. parasuis. Prediction of H. parasuis virulence is currently limited by our scarce understanding of its pathogenicity. Some genes have been associated with H. parasuis virulence, such as lsgB and group 1 vtaA, while biofilm growth has been associated with nonvirulent strains. In this study, 86 H. parasuis nasal isolates from farms that had not had a case of disease for more than 10 years were obtained by sampling piglets at weaning. Isolates were studied by enterobacterial repetitive intergenic consensus PCR and determination of the presence of lsgB and group 1 vtaA, biofilm formation, inflammatory cell response, and resistance to antibiotics. As part of the diversity encountered, a novel 2,661-bp plasmid, named pJMA-1, bearing the blaROB-1 β-lactamase was detected in eight colonizing strains. pJMA-1 was shown to share a backbone with other small plasmids described in the Pasteurellaceae, to be 100% stable, and to have a lower biological cost than the previously described plasmid pB1000. pJMA-1 was also found in nine H. parasuis nasal strains from a separate collection, but it was not detected in isolates from the lesions of animals with Glässer's disease or in nontypeable Haemophilus influenzae isolates. Altogether, we show that commensal H. parasuis isolates represent a reservoir of β-lactam resistance genes which can be transferred to pathogens or other bacteria. PMID:25747001

  9. Detection of Staphylococcal Cassette Chromosome mec Type XI Carrying Highly Divergent mecA, mecI, mecR1, blaZ, and ccr Genes in Human Clinical Isolates of Clonal Complex 130 Methicillin-Resistant Staphylococcus aureus▿†

    PubMed Central

    Shore, Anna C.; Deasy, Emily C.; Slickers, Peter; Brennan, Grainne; O'Connell, Brian; Monecke, Stefan; Ehricht, Ralf; Coleman, David C.

    2011-01-01

    Methicillin resistance in staphylococci is mediated by penicillin binding protein 2a (PBP 2a), encoded by mecA on mobile staphylococcal cassette chromosome mec (SCCmec) elements. In this study, two clonal complex 130 (CC130) methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients in Irish hospitals were identified that were phenotypically PBP 2a positive but lacked mecA by conventional PCR and by DNA microarray screening. The isolates were identified as methicillin-susceptible S. aureus using the GeneXpert real-time PCR assay. Whole-genome sequencing of one isolate (M10/0061) revealed a 30-kb SCCmec element encoding a class E mec complex with highly divergent blaZ-mecA-mecR1-mecI, a type 8 cassette chromosome recombinase (ccr) complex consisting of ccrA1-ccrB3, an arsenic resistance operon, and flanking direct repeats (DRs). The SCCmec element was almost identical to that of SCCmec type XI (SCCmec XI) identified by the Sanger Institute in sequence type 425 bovine MRSA strain LGA251 listed on the website of the International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements. The open reading frames (ORFs) identified within SCCmec XI of M10/0061 exhibited 21 to 93% amino acid identity to ORFs in GenBank. A third DR was identified ca. 3 kb downstream of SCCmec XI, indicating the presence of a possible SCC remnant. SCCmec XI was also identified in the second CC130 MRSA isolate by PCR and sequencing. The CC130 MRSA isolates may be of animal origin as previously reported CC130 S. aureus strains were predominantly from bovine sources. The highly divergent nature of SCCmec XI relative to other SCCmec elements indicates that it may have originated in another taxon. PMID:21636525

  10. Sequence of pNL194, a 79.3-Kilobase IncN Plasmid Carrying the blaVIM-1 Metallo-β-Lactamase Gene in Klebsiella pneumoniae▿

    PubMed Central

    Miriagou, V.; Papagiannitsis, C. C.; Kotsakis, S. D.; Loli, A.; Tzelepi, E.; Legakis, N. J.; Tzouvelekis, L. S.

    2010-01-01

    The nucleotide sequence of pNL194, a VIM-1-encoding plasmid, is described in this study. pNL194 (79,307 bp) comprised an IncN-characteristic segment (38,940 bp) and a mosaic structure (40,367 bp) including blaVIM-1, aacA7, aadA1, aadA2, dfrA1, dfrA12, aphA1, strA, strB, and sul1. Tn1000 or Tn5501 insertion within fipA probably facilitated recruitment of additional mobile elements carrying resistance genes. PMID:20660690

  11. Sequence of pNL194, a 79.3-kilobase IncN plasmid carrying the blaVIM-1 metallo-beta-lactamase gene in Klebsiella pneumoniae.

    PubMed

    Miriagou, V; Papagiannitsis, C C; Kotsakis, S D; Loli, A; Tzelepi, E; Legakis, N J; Tzouvelekis, L S

    2010-10-01

    The nucleotide sequence of pNL194, a VIM-1-encoding plasmid, is described in this study. pNL194 (79,307 bp) comprised an IncN-characteristic segment (38,940 bp) and a mosaic structure (40,367 bp) including bla(VIM-1), aacA7, aadA1, aadA2, dfrA1, dfrA12, aphA1, strA, strB, and sul1. Tn1000 or Tn5501 insertion within fipA probably facilitated recruitment of additional mobile elements carrying resistance genes. PMID:20660690

  12. The Origin(s) of Whales

    NASA Astrophysics Data System (ADS)

    Uhen, Mark D.

    2010-05-01

    Whales are first found in the fossil record approximately 52.5 million years ago (Mya) during the early Eocene in Indo-Pakistan. Our knowledge of early and middle Eocene whales has increased dramatically during the past three decades to the point where hypotheses of whale origins can be supported with a great deal of evidence from paleontology, anatomy, stratigraphy, and molecular biology. Fossils also provide preserved evidence of behavior and habitats, allowing the reconstruction of the modes of life of these semiaquatic animals during their transition from land to sea. Modern whales originated from ancient whales at or near the Eocene/Oligocene boundary, approximately 33.7 Mya. During the Oligocene, ancient whales coexisted with early baleen whales and early toothed whales. By the end of the Miocene, most modern families had originated, and most archaic forms had gone extinct. Whale diversity peaked in the late middle Miocene and fell thereafter toward the Recent, yielding our depauperate modern whale fauna.

  13. Genetic and Biochemical Characterization of an Acquired Subgroup B3 Metallo-β-Lactamase Gene, blaAIM-1, and Its Unique Genetic Context in Pseudomonas aeruginosa from Australia

    PubMed Central

    Yong, Dongeun; Toleman, Mark A.; Bell, Jan; Ritchie, Brett; Pratt, Rachael; Ryley, Henry

    2012-01-01

    Three clinical Pseudomonas aeruginosa isolates (WCH2677, WCH2813, and WCH2837) isolated from the Women's and Children's Hospital, Adelaide, Australia, produced a metallo-β-lactamase (MBL)-positive Etest result. All isolates were PCR negative for known MBL genes. A gene bank was created, and an MBL gene, designated blaAIM-1, was cloned and fully characterized. The encoded enzyme, AIM-1, is a group B3 MBL that has the highest level of identity to THIN-B and L1. It is chromosomal and flanked by two copies (one intact and one truncated) of an ISCR element, ISCR15. Southern hybridization studies indicated the movement of both ISCR15 and blaAIM-1 within the three different clinical isolates. AIM-1 hydrolyzes most β-lactams, with the exception of aztreonam and, to a lesser extent, ceftazidime; however, it possesses significantly higher kcat values for cefepime and carbapenems than most other MBLs. AIM-1 was the first mobile group B3 enzyme detected and signals further problems for already beleaguered antimicrobial regimes to treat serious P. aeruginosa and other Gram-negative infections. PMID:22985886

  14. Genetic and biochemical characterization of an acquired subgroup B3 metallo-β-lactamase gene, blaAIM-1, and its unique genetic context in Pseudomonas aeruginosa from Australia.

    PubMed

    Yong, Dongeun; Toleman, Mark A; Bell, Jan; Ritchie, Brett; Pratt, Rachael; Ryley, Henry; Walsh, Timothy R

    2012-12-01

    Three clinical Pseudomonas aeruginosa isolates (WCH2677, WCH2813, and WCH2837) isolated from the Women's and Children's Hospital, Adelaide, Australia, produced a metallo-β-lactamase (MBL)-positive Etest result. All isolates were PCR negative for known MBL genes. A gene bank was created, and an MBL gene, designated bla(AIM-1), was cloned and fully characterized. The encoded enzyme, AIM-1, is a group B3 MBL that has the highest level of identity to THIN-B and L1. It is chromosomal and flanked by two copies (one intact and one truncated) of an ISCR element, ISCR15. Southern hybridization studies indicated the movement of both ISCR15 and bla(AIM-1) within the three different clinical isolates. AIM-1 hydrolyzes most β-lactams, with the exception of aztreonam and, to a lesser extent, ceftazidime; however, it possesses significantly higher k(cat) values for cefepime and carbapenems than most other MBLs. AIM-1 was the first mobile group B3 enzyme detected and signals further problems for already beleaguered antimicrobial regimes to treat serious P. aeruginosa and other Gram-negative infections. PMID:22985886

  15. Lysine N[superscript zeta]-Decarboxylation Switch and Activation of the [beta]-Lactam Sensor Domain of BlaR1 Protein of Methicillin-resistant Staphylococcus aureus

    SciTech Connect

    Borbulevych, Oleg; Kumarasiri, Malika; Wilson, Brian; Llarrull1, Leticia I.; Lee, Mijoon; Hesek, Dusan; Shi, Qicun; Peng, Jeffrey; Baker, Brian M.; Mobashery, Shahriar

    2012-10-29

    The integral membrane protein BlaR1 of methicillin-resistant Staphylococcus aureus senses the presence of {beta}-lactam antibiotics in the milieu and transduces the information to the cytoplasm, where the biochemical events that unleash induction of antibiotic resistance mechanisms take place. We report herein by two-dimensional and three-dimensional NMR experiments of the sensor domain of BlaR1 in solution and by determination of an x-ray structure for the apo protein that Lys-392 of the antibiotic-binding site is posttranslationally modified by N{sup {zeta}}-carboxylation. Additional crystallographic and NMR data reveal that on acylation of Ser-389 by antibiotics, Lys-392 experiences N{sup {zeta}}-decarboxylation. This unique process, termed the lysine N{sup {zeta}}-decarboxylation switch, arrests the sensor domain in the activated ('on') state, necessary for signal transduction and all the subsequent biochemical processes. We present structural information on how this receptor activation process takes place, imparting longevity to the antibiotic-receptor complex that is needed for the induction of the antibiotic-resistant phenotype in methicillin-resistant S. aureus.

  16. Multiple origins of life

    NASA Technical Reports Server (NTRS)

    Raup, D. M.; Valentine, J. W.

    1983-01-01

    There is some indication that life may have originated readily under primitive earth conditions. If there were multiple origins of life, the result could have been a polyphyletic biota today. Using simple stochastic models for diversification and extinction, we conclude: (1) the probability of survival of life is low unless there are multiple origins, and (2) given survival of life and given as many as 10 independent origins of life, the odds are that all but one would have gone extinct, yielding the monophyletic biota we have now. The fact of the survival of our particular form of life does not imply that it was unique or superior.

  17. Local tolerance and stability up to 24 months of a new 20% proline-stabilized polyclonal immunoglobulin for subcutaneous administration.

    PubMed

    Maeder, Werner; Lieby, Patricia; Sebald, Andrea; Spycher, Martin; Pedrussio, Renzo; Bolli, Reinhard

    2011-01-01

    Subcutaneous administration of human IgG is an alternative to intravenous replacement therapy that is associated with more stable serum IgG levels and fewer systemic adverse events. Highly concentrated IgG solutions are most convenient to minimize infusion volume, but their preparation and stability presents substantial technical difficulties. We report on the stability and local tolerance of IgPro20, an l-proline-stabilized, 20% polyvalent human IgG developed for subcutaneous administration. Stability was tested according to ICH guidelines. Local tolerance and vasoactivity were examined in rabbit and rat models, respectively. The presence of l-proline in IgPro20 reduced viscosity and addition of Polysorbate 80 and inert gassing improved the appearance of the solution. After storage at 25 °C for 24 months, monomer + dimer content, aggregates, and fragments were within specification (≥ 90.0%, ≤ 4.0%, and ≤ 10.0%, respectively), and Fc function and antibody activities were maintained. In rats, intravenous injection of IgPro20 produced mild and transient hypotension comparable to that seen with intravenous IgG products. Local tolerance of IgPro20 in rabbits was comparable to that of a marketed subcutaneous IgG, Beriglobin P. Functionality and quality of IgPro20 are maintained during storage at 25 °C for at least 24 months. The product is well tolerated as assessed in animal models. PMID:21257320

  18. Chemical Origins of Life

    ERIC Educational Resources Information Center

    Fox, J. Lawrence

    1972-01-01

    Reviews ideas and evidence bearing on the origin of life. Shows that evidence to support modifications of Oparin's theories of the origin of biological constituents from inorganic materials is accumulating, and that the necessary components are readily obtained from the simple gases found in the universe. (AL)

  19. The Moon's Origin.

    ERIC Educational Resources Information Center

    Cadogan, Peter

    1983-01-01

    Presents findings and conclusions about the origin of the moon, favoring the capture hypothesis of lunar origin. Advantage of the hypothesis is that it allows the moon to have been formed elsewhere, specifically in a hotter part of the solar nebula, accounting for chemical differences between earth and moon. (JN)

  20. DNA Replication Origins

    PubMed Central

    Leonard, Alan C.; Méchali, Marcel

    2013-01-01

    The onset of genomic DNA synthesis requires precise interactions of specialized initiator proteins with DNA at sites where the replication machinery can be loaded. These sites, defined as replication origins, are found at a few unique locations in all of the prokaryotic chromosomes examined so far. However, replication origins are dispersed among tens of thousands of loci in metazoan chromosomes, thereby raising questions regarding the role of specific nucleotide sequences and chromatin environment in origin selection and the mechanisms used by initiators to recognize replication origins. Close examination of bacterial and archaeal replication origins reveals an array of DNA sequence motifs that position individual initiator protein molecules and promote initiator oligomerization on origin DNA. Conversely, the need for specific recognition sequences in eukaryotic replication origins is relaxed. In fact, the primary rule for origin selection appears to be flexibility, a feature that is modulated either by structural elements or by epigenetic mechanisms at least partly linked to the organization of the genome for gene expression. PMID:23838439

  1. The Growth of Originalism

    ERIC Educational Resources Information Center

    Bork, Robert H.

    2011-01-01

    The latest episode in the long-running struggle for control of the Constitution, and the political power that goes with it, is playing out in the federal courts in California. The contending philosophies are originalism, which holds that the Constitution should be read as it was originally understood by the framers and ratifiers, and the congeries…

  2. Originalism in the Classroom

    ERIC Educational Resources Information Center

    Forte, David F.

    2011-01-01

    In this article, the author provides a detailed legal history of originalism and investigates whether, and to what extent, originalism is a part of law school teaching on the Constitution. He shares the results of an examination of the leading constitutional law textbooks used in the top fifty law schools and a selection of responses gathered from…

  3. Religion: Origins and Evolution.

    ERIC Educational Resources Information Center

    Meyer, John K.

    2004-01-01

    We present the purpose of study of the origins and development of affect-relevant and religion-relevant hypotheses, and conjectured prediction of proto-religious sequences in pre-human anthropoids and primitive human cultures. We anticipate more comprehensive study of modern cultural outcomes of these origins and developments.

  4. Extended-spectrum beta-lactamase-producing Shiga toxin gene (stx1)-positive Escherichia coli O91:H14 carrying blaCTX-M-15 on an IncI1-ST31 plasmid isolated from a human patient in Germany.

    PubMed

    Arvand, Mardjan; Bettge-Weller, Gudrun; Fruth, Angelika; Uphoff, Helmut; Pfeifer, Yvonne

    2015-05-01

    In 2011, the Shiga toxin- and extended-spectrum β-lactamase (ESBL)-producing Escherichia coli O104:H4 caused a serious outbreak of gastroenteritis in Germany. This strain carried bla(CTX-M-15) and bla(TEM-1) on an IncI1-ST31 plasmid. During screening of individuals at risk for acquisition of the epidemic E. coli O104:H4, we isolated another ESBL-producing and Shiga toxin-positive E. coli belonging to serotype O91:H14 from feces of a human patient. Interestingly, the patient also carried a further ESBL-producing but Shiga toxin-negative E. coli. Both strains harbored bla(CTX-M-15) and bla(TEM-1) on an IncI1-ST31 plasmid, which was indistinguishable regarding size and plasmid restriction pattern from the plasmid of the epidemic E. coli O104:H4 strain. The patient had traveled to India 6 months prior to the isolation of the E. coli strains. This is the first report of an ESBL-producing, Shiga toxin-positive E. coli of serogroup O91. Our data suggest a high propensity of the IncI1-ST31 plasmid to spread in the human and/or animal population. PMID:25801683

  5. [Hypotension from endocrine origin].

    PubMed

    Vantyghem, Marie-Christine; Douillard, Claire; Balavoine, Anne-Sophie

    2012-11-01

    Hypotension is defined by a low blood pressure either permanently or only in upright posture (orthostatic hypotension). In contrast to hypertension, there is no threshold defining hypotension. The occurrence of symptoms for systolic and diastolic measurements respectively below 90 and 60 mm Hg establishes the diagnosis. Every acute hypotensive event should suggest shock, adrenal failure or an iatrogenic cause. Chronic hypotension from endocrine origin may be linked to adrenal failure from adrenal or central origin, isolated hypoaldosteronism, pseudohypoaldosteronism, pheochromocytoma, neuro-endocrine tumors (carcinoïd syndrome) or diabetic dysautonomia. Hypotension related to hypoaldosteronism associates low blood sodium and above all high blood potassium levels. They are generally classified according to their primary (hyperreninism) or secondary (hyporeninism) adrenal origin. Isolated primary hypoaldosteronisms are rare in adults (intensive care unit, selective injury of the glomerulosa area) and in children (aldosterone synthase deficiency). Isolated secondary hypoaldosteronism is related to mellitus diabetes complicated with dysautonomia, kidney failure, age, iatrogenic factors, and HIV infections. In both cases, they can be associated to glucocorticoid insufficiency from primary adrenal origin (adrenal failure of various origins with hyperreninism, among which congenital 21 hydroxylase deficiency with salt loss) or from central origin (hypopituitarism with hypo-reninism). Pseudohypoaldosteronisms are linked to congenital (type 1 pseudohypoaldosteronism) or acquired states of resistance to aldosterone. Acquired salt losses from enteric (total colectomy with ileostomy) or renal (interstitial nephropathy, Bartter and Gitelman syndromes…) origin might be responsible for hypotension and are associated with hyperreninism-hyperaldosteronism. Hypotension is a rare manifestation of pheochromocytomas, especially during surgical removal when the patient has not been

  6. blaCMY-2-positive IncA/C plasmids from escherichia coli and salmonella enterica are a distinct component of a larger lineage of plasmids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large multidrug resistance plasmids of the A/C incompatibility complex (IncA/C) have been found in a diverse group of Gram-negative commensal and pathogenic bacteria. We present three completed sequences from IncA/C plasmids that originated from Escherichia coli (cattle) and Salmonella enterica sero...

  7. Molecular Characterization and Computational Modelling of New Delhi Metallo-β-Lactamase-5 from an Escherichia coli Isolate (KOEC3) of Bovine Origin.

    PubMed

    Purkait, D; Ahuja, A; Bhattacharjee, U; Singha, A; Rhetso, K; Dey, T K; Das, S; Sanjukta, R K; Puro, K; Shakuntala, I; Sen, A; Banerjee, A; Sharma, I; Bhatta, R S; Mawlong, M; Guha, C; Pradhan, N R; Ghatak, S

    2016-06-01

    Emergence of antimicrobial resistance mediated through New Delhi metallo-β-lactamases (NDMs) is a serious therapeutic challenge. Till date, 16 different NDMs have been described. In this study, we report the molecular and structural characteristics of NDM-5 isolated from an Escherichia coli isolate (KOEC3) of bovine origin. Using PCR amplification, cloning and sequencing of full blaNDM gene, we identified the NDM type as NDM-5. Cloning of full gene in E. coli DH5α and subsequent assessment of antibiotic susceptibility of the transformed cells indicated possible role of native promoter in expression blaNDM-5. Translated amino acid sequence had two substitutions (Val88Leu and Met154Leu) compared to NDM-1. Theoretically deduced isoelectric pH of NDM-5 was 5.88 and instability index was 36.99, indicating a stable protein. From the amino acids sequence, a 3D model of the protein was computed. Analysis of the protein structure elucidated zinc coordination and also revealed a large binding cleft and flexible nature of the protein, which might be the reason for broad substrate range. Docking experiments revealed plausible binding poses for five carbapenem drugs in the vicinity of metal ions. In conclusion, results provided possible explanation for wide range of antibiotics catalyzed by NDM-5 and likely interaction modes with five carbapenem drugs. PMID:27570310

  8. Tektites and their origin

    NASA Technical Reports Server (NTRS)

    Okeefe, J. A.

    1976-01-01

    Questions concerning the tektite distribution are examined, taking into account the Australasian strewn field, the Ivory Coast strewn field, the Moldavite strewn field, the North American strewn field, the Libyan desert glass, the Aouelloul crater glass, and amerikanites. Attention is given to the shapes of tektites, the internal structure of tektites, the physical properties of tektite glass, the chemical composition of tektites, isotopes, fission tracks, cosmic ray tracks, and arguments in favor and against the terrestrial origin of tektites. It is concluded that tektites cannot be terrestrial in origin. They are probably volcanic ejects, of geologically recent epochs, from one or a number of lunar volcanoes.

  9. Conscientiousness: Origins in Childhood?

    ERIC Educational Resources Information Center

    Eisenberg, Nancy; Duckworth, Angela L.; Spinrad, Tracy L.; Valiente, Carlos

    2014-01-01

    In this review, we evaluate developmental and personality research with the aim of determining whether the personality trait of conscientiousness can be identified in children and adolescents. After concluding that conscientiousness does emerge in childhood, we discuss the developmental origins of conscientiousness with a specific focus on…

  10. The Origins of Mass

    SciTech Connect

    Lincoln, Don

    2014-07-30

    The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

  11. Origins of Coordinate Searching.

    ERIC Educational Resources Information Center

    Kilgour, Frederick G.

    1997-01-01

    Reviews the origins of post-coordinate searching and emphasizes that the focal point should be on the searcher, not on the item being indexed. Highlights include the history of the term information retrieval; edge notched punch cards; the "peek-a-boo" system; the Uniterm system; and using computers to search for information. (LRW)

  12. Origin of Fire.

    ERIC Educational Resources Information Center

    Bennett, Ruth, Ed.

    Intended for use with college students, this booklet contains a traditional Hupa story (in Hupa and English) followed by information to aid in a critical literary analysis of the story and topics for student discussion. The introduction explains that "Origin of Fire"--first written down by P.E. Goddard in 1902 and still told by contemporary…

  13. The Origin of Life

    ERIC Educational Resources Information Center

    Hodson, D.

    1975-01-01

    Presents an outline of lectures given on this topic to British secondary students. Man's various ideas about the origin of life are included in three categories: those that consider life to have been created by a Divine Being; those that consider life to have developed from non-living matter; and those that consider life to be eternal. (MLH)

  14. Originality and Creativity.

    ERIC Educational Resources Information Center

    Tan, Shaun

    This paper discusses the creative process of one author, a professional author/illustrator of picture books. The paper muses about the meaning of creativity and originality and states inspiration has to do with careful research and looking for a challenge. Creativity is about testing one proposition against another and seeing how things combine…

  15. The Origins of Mass

    ScienceCinema

    Lincoln, Don

    2014-08-07

    The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

  16. The Origins of Writing.

    ERIC Educational Resources Information Center

    Schmandt-Besserat, Denise

    Writing appears to have originated from a modest system of counters or tokens used to keep track of economic goods and transactions. This system of recording appeared in 8000 B. C. in Mesopotamia, or what is now Iraq. The tokens' consistency in shape and size during the next 4,000 years attests to the stability of the agricultural economy and way…

  17. The Origin of Gravitation

    NASA Astrophysics Data System (ADS)

    Zheng, Sheng Ming

    2012-10-01

    In the natural world, people have discovered four kinds of forces: electromagnetic force, gravitation, weak force, and strong force. Although the gravitation has been discovered more than three hundred years, its mechanism of origin is unclear until today. While investigating the origin of gravitation, I do some experiments discover the moving photons produce gravitation. This discovery shows the origin of gravitation. Meanwhile I do some experiments discover the light interference fringes are produced by the gravitation: my discovery demonstrate light is a particle, but is not a wave-particle duality. Furthermore, applications of this discovery to other moving particles show a similar effect. In a word: the micro particle moving produce gravitation and electromagnetic force. Then I do quantity experiment get a general formula: Reveal the essence of gravitational mass and the essence of electric charge; reveal the origin of gravitation and the essence of matter wave. Along this way, I unify the gravitation and electromagnetic force. Namely I find a natural law that from atomic world to star world play in moving track. See website: https://www.lap-publishing.com/catalog/details/store/gb/book/978-3-8473-2658-8/mechanism-of-interaction-in-moving-matter

  18. The origin of comets

    NASA Astrophysics Data System (ADS)

    Bailey, M. E.; Clube, S. V. M.; Napier, W. M.

    Theories of the nature and origin of comets are discussed in a historical review covering the period from ancient times to the present. Consideration is given to the ancient controversy as to the atmospheric or celestial nature of comets, Renaissance theories of comet orbits, superstitions regarding the effects of comets, Kant's (1755) theory of solar-system origin, the nineteenth-century discovery of the relationship between comets and meteor showers, and the continuing solar-system/interstellar debate. Oort's (1950) model of a comet swarm surrounding the solar system is examined in detail; arguments advanced to explain the formation of comets within this model are summarized; and the question of cometary catastrophism is addressed.

  19. Bioenergetics and Life's Origins

    PubMed Central

    Deamer, David; Weber, Arthur L.

    2010-01-01

    Bioenergetics is central to our understanding of living systems, yet has attracted relatively little attention in origins of life research. This article focuses on energy resources available to drive primitive metabolism and the synthesis of polymers that could be incorporated into molecular systems having properties associated with the living state. The compartmented systems are referred to as protocells, each different from all the rest and representing a kind of natural experiment. The origin of life was marked when a rare few protocells happened to have the ability to capture energy from the environment to initiate catalyzed heterotrophic growth directed by heritable genetic information in the polymers. This article examines potential sources of energy available to protocells, and mechanisms by which the energy could be used to drive polymer synthesis. PMID:20182625

  20. Origin of Life

    NASA Astrophysics Data System (ADS)

    Lal, Ashwini Kumar

    2008-10-01

    The evolution of life has been a big enigma despite rapid advancements in the field of astrobiology, microbiology and genetics in recent years. The answer to this puzzle is as mindboggling as the riddle relating to evolution of the universe itself. Despite the fact that panspermia has gained considerable support as a viable explanation for origin of life on the earth and elsewhere in the universe, the issue, however, remains far from a tangible solution. This paper examines the various prevailing hypotheses regarding origin of life-like abiogenesis, RNA world, iron-sulphur world and panspermia, and concludes that delivery of life-bearing organic molecules by the comets in the early epoch of the earth alone possibly was not responsible for kick-starting the process of evolution of life on our planet.

  1. Endosymbionts and mitochondrial origins

    NASA Technical Reports Server (NTRS)

    Woese, C. R.

    1977-01-01

    The possibility is put forth that the mitochondrion did not originate from an endosymbiosis 1-2 billion years ago involving an aerobic bacterium. Rather, it arose by endosymbiosis in a much earlier anaerobic period and was initially a photosynthetic organelle analogous to the modern chloroplast. This suggestion arises from a reconsideration of the nature of endosymbiosis. It explains the remarkable diversity in mitochondrial information storage and processing systems.

  2. The origin of ozone

    NASA Astrophysics Data System (ADS)

    Grewe, V.

    2006-05-01

    Highest atmospheric ozone production rates can be found at around 30 km in the tropical stratosphere, leading to ozone mixing ratios of about 10 ppmv. Those stratospheric air masses are then transported to extra-tropical latitudes via the Brewer-Dobson circulation. This is considered the main mechanism to generate mid- and high latitude ozone. By applying the climate-chemistry models E39/C and MAECHAM4/CHEM, this view is investigated in more detail. The origin of ozone in the troposphere and stratosphere is analysed, by incorporating a diagnostics ("marked ozone origin tracers") into the models, which allows to identify the origin of ozone. In most regions the simulated local ozone concentration is dominated by local ozone production, i.e. less than 50% of the ozone at higher latitudes of the stratosphere is produced in the tropics, which conflicts with the idea that the tropics are the global source for stratospheric ozone. Although episodic stratospheric intrusions occur basically everywhere, the main ozone stratosphere-to-troposphere exchange is connected to exchange processes at the sub-tropical jet-stream. The simulated tropospheric influx of ozone amounts to 420 Tg per year, and originates in the Northern Hemisphere from the extra-tropical stratosphere, whereas in the Southern Hemisphere a re-circulation of tropical tropospheric ozone contributes most to the influx of ozone into the troposphere. In the model E39/C, the upper troposphere of both hemispheres is clearly dominated by tropical tropospheric ozone (40%-50%) except for northern summer hemisphere, where the tropospheric contribution (from the tropics as well as from the Northern Hemisphere) does not exceed 20%.

  3. Origins of magnetospheric plasma

    SciTech Connect

    Moore, T.E. )

    1991-01-01

    A review is given of recent (1987-1990) progress in understanding of the origins of plasmas in the earth's magnetosphere. In counterpoint to the early supposition that geomagnetic phenomena are produced by energetic plasmas of solar origin, 1987 saw the publication of a provocative argument that accelerated ionospheric plasma could supply all magnetospheric auroral and ring current particles. Significant new developments of existing data sets, as well as the establishment of entirely new data sets, have improved the ability to identify plasma source regions and to track plasma through the magnetospheric system of boundary layers and reservoirs. These developments suggest that the boundary between ionospheric and solar plasmas, once taken to lie at the plasmapause, actually lies much nearer to the magnetopause. Defining this boundary as the surface where solar wind and ionosphere contribute equally to the plasma, it is referred to herein as the 'geopause'. It is now well established that the infusion of ionospheric O(+) plays a major role in the storm-time distention of the magnetotail and inflation of the inner magnetosphere. After more than two decades of observation and debate, the question remains whether magnetosheric are protons of solar or terrestrial origin. 161 refs.

  4. Origins of flower morphology.

    PubMed

    Endress, P K

    2001-08-15

    Flowers evolved in many steps, probably starting long before flowering plants (angiophytes) originated. Certain parts of flowers are conservative and have not changed much during evolution; others are evolutionarily highly plastic. Here conservative features are discussed and an attempt is made to trace them back through their evolutionary history. Microsporangia and ovules (which develop into seeds) are preangiophyte floral elements. Angiospermy, combined with postgenital fusion, was the most prominent key innovation in angiophytes. Angiospermy and thecal organization of stamens originated earlier than all clades of extant angiosperms (the crown group of angiophytes). Differentiation of a perianth into calyx and corolla and syncarpy appeared after the first branching of the basalmost clades of extant angiosperms. Sympetaly and floral tubes as well as tenuinucellar, unitegmic ovules originated as major innovations in the clade that led to asterids. An obvious trend in flower evolution is increased synorganisation of parts, which led to new structures. Fixation of floral organ number and position was a precondition for synorganization. Concomitantly, plasticity changed from number and position of organs to shape of the new structures. Character distribution mapped onto cladograms indicates that key innovations do not appear suddenly, but start with trials and only later become deeply rooted genetically in the organization. This is implied from the common occurrence of reversals in the early history of an innovation. J. Exp. Zool. (Mol. Dev. Evol.) 291:105-115, 2001. PMID:11479912

  5. Origin of tektites

    NASA Technical Reports Server (NTRS)

    O'Keefe, John A.

    1994-01-01

    The origin of tektites has been obscure because of the following dilemma. The application of physical principles to the data available on tektites points strongly to origin from one or more lunar volcanoes; but few glasses of tektite composition have hitherto been reported from the lunar samples. Instead, the lunar silicic glasses consist chiefly of a material very rich in K2O and poor in MgO. The ratio of K2O/MgO is higher in these glasses than in any tektites reported. The solution of the dilemma seems to come from the study of some recently discovered terrestrial deposits of tektite glass with high values of K2O/MgO at the Cretaceous Tertiary boundary. These glasses are found to be very vulnerable to crystallization into sandine or to alteration to smectite. These end products are known and are more abundant than any terrestrial deposits of tektite glass. It seems possible that, in fact, the moon produces tektite glass, mostly of the high K2O-low MgO type; but on Earth these deposits are destroyed. The much less abundant deposits with lower K and higher Mg are observed because they survive. Other objections to the lunar origin hypothesis appear to be answerable.

  6. COSMIC ORIGINS SPECTROGRAPH AND FUSE OBSERVATIONS OF T {approx} 10{sup 5} K GAS IN A NEARBY GALAXY FILAMENT

    SciTech Connect

    Narayanan, Anand; Wakker, Bart P.; Savage, Blair D.; Keeney, Brian A.; Shull, J. Michael; Stocke, John T.; Sembach, Kenneth R. E-mail: wakker@astro.wisc.ed

    2010-10-01

    We present a clear detection of a broad Ly{alpha} absorber (BLA) with a matching O VI line in the nearby universe. The BLA is detected at z(Ly{alpha})=0.01028 in the high signal-to-noise ratio spectrum of Mrk 290 obtained using the Cosmic Origins Spectrograph. The Ly{alpha} absorption has two components, with b(H i) = 55{+-}1 km s{sup -1} and b(H i) = 33{+-}1 km s{sup -1}, separated in velocity by v {approx} 115 km s{sup -1}. The O VI, detected by the Far-Ultraviolet Spectroscopic Explorer at z(O vi) = 0.01027, has a b(O vi) = 29{+-}3 km s{sup -1} and is kinematically well aligned with the broader H I component. The non-detection of other ions such as C II, Si II, Fe II, C III, Si III, C IV, Si IV, and N V at the same velocity as the BLA and the O VI implies that the absorber is tracing highly ionized gas. The different line widths of the BLA and O VI suggest a temperature of T = 1.4 x 10{sup 5} K in the absorber. Photoionization, collisional ionization equilibrium as well as non-equilibrium collisional ionization models do not explain the ion ratios at this temperature. The observed line strength ratios and line widths favor an ionization scenario in which both ion-electron collisions and UV photons contribute to the ionization in the gas. Such a model requires a low metallicity of {approx}-1.7 dex, ionization parameter of log U {approx} -1.4, a large total hydrogen column density of N(H) {approx} 4 x 10{sup 19} cm{sup -2}, and a path length of {approx}400 kpc. The line of sight to Mrk 290 intercepts at the redshift of the absorber, a megaparsec scale filamentary structure extending over {approx}20{sup 0} in the sky, with several luminous galaxies distributed within {approx}1.5 h {sup -1} Mpc projected distance from the absorber. The collisionally ionized gas phase of this absorber is most likely tracing a shock-heated gaseous structure, consistent with a few different scenarios for the origin including an overdense region of the warm-hot intergalactic medium in

  7. [Carriage of class 1 and 2 integrons in Acinetobacter baumannii and Pseudomonas aeruginosa isolated from clinical specimens and a novel gene cassette array: blaOXA-11-cmlA7].

    PubMed

    Mengeloğlu, Fırat Zafer; Copur Çiçek, Ayşegül; Koçoğlu, Esra; Sandallı, Cemal; Budak, Emine Esra; Ozgümüş, Osman Birol

    2014-01-01

    cassettes. IntI2 gene was not detected in any of the isolates. Resistance to piperacillin/tazobactam, ceftazidime, cefepime, ceftriaxone and ampicillin/sulbactam was detected as the common resistance pattern in all integron-positive A.baumannii strains, whereas resistance to ceftazidime, gentamicin and ciprofloxacin was the common pattern in all integron-positive P.aeruginosa strains. DNA sequence analysis of variable regions of integrons indicated that two separate gene cassette arrays (aacC1-aadA1 and aac(3)-1) were carried by A.baumannii strains, and two types of gene cassette arrays (blaOXA-30-aadA1 and blaOXA-11-cmlA7) were carried by P.aeruginosa strains. To our best knowledge, this is the first report of the gene sequence of blaOXA-11-cmlA7 defined in an integron gene cassette of P.aeruginosa. PMID:24506715

  8. Origin of earth's moon

    NASA Technical Reports Server (NTRS)

    Wood, J. A.

    1977-01-01

    The major geochemical properties of the moon are briefly considered along with the significant facts of the moon's geologic history, and then the three current hypotheses regarding the moon's origin, namely, fission, capture, and binary accretion, are reviewed. The individual merits and improbabilities associated with each mechanism are taken into consideration. Special attention is given to the binary accretion model as the most promising one. In the variants of this model, of crucial importance is the nature of the more general hypothesis assumed for planetary formation from the solar nebula. The two main models differ considerably in the amount of chemical fractionation they allow to accompany planetary formation.

  9. The Origin of Echocardiography

    PubMed Central

    Singh, Siddharth; Goyal, Abha

    2007-01-01

    The original description of M-mode echocardiography in 1953, by Inge Edler (1911–2001) and his physicist friend Hellmuth Hertz, marked the beginning of a new diagnostic noninvasive technique. Edler used this technique primarily for the preoperative study of mitral stenosis and diagnosis of mitral regurgitation. His work was carried forward by cardiologists all over the world, who developed Doppler, 2-dimensional, contrast, and transesophageal echocardiography. These are now standard in cardiologic examinations. Edler also influenced neurologists and obstetricians at Lund University (Sweden) to use ultrasound in their fields. For his landmark discovery, Edler is recognized as the “Father of Echocardiography.” PMID:18172524

  10. Origin of Tektites.

    PubMed

    O'keefe, J A; Shute, B E

    1963-03-29

    A comet of the size recently postulated by H. C. Urey would leave a large crater. It is shown, from aerodynamic theory, from observations of distribution around terrestrial impact craters, and from experimental nuclear explosions, that the observed distribution of tektites cannot be the result of impact on the earth, whether cometary or meteoritic. It is further shown, from aerodynamic theory, from observation of a meteor shower, and from study of the breakup of artificial satellites, that the distribution of tektites can be accounted for as a result of fusion stripping of a satellite, as originally suggested by Suess. PMID:17757065

  11. Origins of Bladder Cancer.

    PubMed

    Czerniak, Bogdan; Dinney, Colin; McConkey, David

    2016-05-23

    Bladder cancer, one of the most frequently occurring human cancers, develops via two tracks referred to as papillary and nonpapillary that correspond to clinically different forms of the disease. Most bladder cancers are chemically induced, with tobacco smoking being the leading risk factor. Recent advances in bladder cancer research have enhanced our understanding of the origin of this disease from urothelial progenitor cells via field effects along papillary/luminal and nonpapillary/basal pathways. Evident from the outset of the disease, the diversity of the luminal and basal pathways, together with cell lineage tracing studies, postulates the origin of molecularly distinct subtypes from different uroprogenitor cells. The molecular mechanisms initiating field effects involve a new class of genes referred to as forerunner (FR) genes that generally map around major tumor suppressors such as RB1. These genes are silenced, predominantly by hypermethylation and less frequently by mutations, and drive the expansion of intraurothelial preneoplastic cells. Different FR genes are involved in various molecular subtypes of bladder cancer and they sensitize the uroprogenitor cells to the development of luminal and basal bladder cancers in animal models. In human bladder cancer, luminal and basal forms have dissimilar clinical behavior and response to conventional and targeted chemotherapeutic manipulations. These new research developments hold the promise of expanding our armamentarium of diagnostic and treatment options for patients with bladder cancer and improving our ability to select patients most likely to respond to a specific therapy. PMID:26907529

  12. The Origins of Options

    PubMed Central

    Smaldino, Paul E.; Richerson, Peter J.

    2012-01-01

    Most research on decision making has focused on how human or animal decision makers choose between two or more options, posed in advance by the researchers. The mechanisms by which options are generated for most decisions, however, are not well understood. Models of sequential search have examined the trade-off between continued exploration and choosing one’s current best option, but still cannot explain the processes by which new options are generated. We argue that understanding the origins of options is a crucial but untapped area for decision making research. We explore a number of factors which influence the generation of options, which fall broadly into two categories: psycho-biological and socio-cultural. The former category includes factors such as perceptual biases and associative memory networks. The latter category relies on the incredible human capacity for culture and social learning, which doubtless shape not only our choices but the options available for choice. Our intention is to start a discussion that brings us closer toward understanding the origins of options. PMID:22514515

  13. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Dry dock 2 with six destroyers; 1922 - Mare Island Naval Shipyard, Drydock No. 2, California Avenue, east side near Ninth Street, Vallejo, Solano County, CA

  14. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Building 253; 1920. - Mare Island Naval Shipyard, Supply Building, Walnut Avenue, southeast corner of Walnut Avenue & Fifth Street, Vallejo, Solano County, CA

  15. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Coal sheds with coals; 1906. - Mare Island Naval Shipyard, Coal Sheds, Waterfront Avenue, northwest corner of Waterfront Avenue & Fourth Street, Vallejo, Solano County, CA

  16. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. View of waterfront during World War II; N.D. - Mare Island Naval Shipyard, East of Nave Drive, Vallejo, Solano County, CA

  17. 10. Photographic copy of original drawings (originals at Amtrack, Philadelphia, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Photographic copy of original drawings (originals at Amtrack, Philadelphia, Pennsylvania) PLANS FOR FLOORBEAMS, SWAYS AND RAIL POSTS - Water Street Bridge, US Route 1 spanning Metro-North Commuter Railroad, New Haven, New Haven County, CT

  18. 11. Photographic copy of original drawings (originals at Amtrack, Philadelphia, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Photographic copy of original drawings (originals at Amtrack, Philadelphia, Pennsylvania) END POST AND CHORDS - Water Street Bridge, US Route 1 spanning Metro-North Commuter Railroad, New Haven, New Haven County, CT

  19. 2. Photocopy of original photograph (Original in collection of Historical ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Photocopy of original photograph (Original in collection of Historical Society of Montana) MAIN AND SIDE ELEVATIONS, SHOWING AWNINGS LOWERED OVER PORCH - W. C. Child Ranch, State Highway 279, Helena, Lewis and Clark County, MT

  20. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Building H1; 1920. - Mare Island Naval Shipyard, Hospital Headquarters, Johnson Lane, west side at intersection of Johnson Lane & Cossey Street, Vallejo, Solano County, CA

  1. 26. Photocopy of Original Drawing (original in the State of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. Photocopy of Original Drawing (original in the State of Michigan Record Center) ELEVATION, COMBINED LIGHT AND TROLLEY STANDARD AND DETAIL OF CAST IRON MANHOLE COVER - Monroe Street Bridge, Spanning River Raisin at Monroe Street, Monroe, Monroe County, MI

  2. 23. Photocopy of Original Drawing (original in the State of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. Photocopy of Original Drawing (original in the State of Michigan Record Center) PLAN, SIDE ELEVATION, AND SECTIONAL PLAN FOR PIERS 1, 2, AND 3 - Monroe Street Bridge, Spanning River Raisin at Monroe Street, Monroe, Monroe County, MI

  3. 24. Photocopy of Original Drawing (original in the State of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. Photocopy of Original Drawing (original in the State of Michigan Record Center) SECTIONS OF TYPICAL GIRDERS - Monroe Street Bridge, Spanning River Raisin at Monroe Street, Monroe, Monroe County, MI

  4. 13. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) ARMY SUPPLY BASE-PLAN OF CONSTRUCTION PLANT - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  5. 15. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) TYPICAL DETAILS-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  6. 21. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) ERECTION PLAN-PIER NO. 4 - Brooklyn Army Supply Base, Pier 4, Brooklyn, Kings County, NY

  7. 19. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) BRIDGES BETWEEN WAREHOUSE A AND PIERS - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  8. 14. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) SECTIONS AND DETAILS-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  9. 18. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) PLANS AND SECTIONS, MECHANICAL EQUIPMENT-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  10. 16. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) DETAILS OF INSHORE ENDS-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  11. 17. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) DETAILS OF OUTSHORE ENDS-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  12. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. QUARTERS A IN THE SNOW; 1913. - Mare Island Naval Shipyard, Commandant's Quarters, Walnut Avenue, west side near Eighth Street, Vallejo, Solano County, CA

  13. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Dry dock 1 with sailing ship, 1899. - Mare Island Naval Shipyard, Drydock No. 1, California Avenue, east side near Ninth Street, Vallejo, Solano County, CA

  14. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. View of sawmill after earthquake of 1898. - Mare Island Naval Shipyard, East of Nave Drive, Vallejo, Solano County, CA

  15. Persistence of related bla-IMP-4 metallo-beta-lactamase producing Enterobacteriaceae from clinical and environmental specimens within a burns unit in Australia - a six-year retrospective study

    PubMed Central

    2013-01-01

    Background To describe the clinical epidemiology, environmental surveillance and infection control interventions undertaken in a six-year persistence of bla-IMP-4 metallo-beta-lactamase (MBL) producing Enterobacteriaceae within a separately confined hospital burns unit in a tertiary hospital in Sydney, Australia. Methods MBL positive clinical and environmental isolates were collected from the Burns Unit, from the first detection of isolates in September 2006 to August 2012. Unit-acquired clinical isolates were included, and patient outcomes analyzed amongst those who acquired clinically significant infections. Environmental isolates were analyzed with regard to relationship to clinical isolates, bacterial species, and persistence despite cleaning efforts. Results Thirty clinical isolates detected from 23 patients were identified. Clinically significant infection developed in 7 (30%) patients – 2 bacteremias, 2 central venous catheter tip infections without bacteremia, and 3 wound infections. All patients survived at 30 days. Seventy-one environmental isolates were confirmed to be MBL-positive, with 85% sourced from shower facilities or equipment. MBL organisms persisted at these sites despite both usual hospital cleaning, and following targeted environmental disinfection interventions. Conclusions Clear association exists between environmental Burns Unit contamination by MBLs and subsequent patient colonization. Clinical infection occurred in a small proportion of patients colonized by MBLs, and with generally favorable outcomes. Its persistence in the Burns Unit environment, despite concerted infection control measures, pose concern for ongoing clinical transmission. PMID:24345195

  16. Mechanical origin of aftershocks.

    PubMed

    Lippiello, E; Giacco, F; Marzocchi, W; Godano, C; de Arcangelis, L

    2015-01-01

    Aftershocks are the most striking evidence of earthquake interactions and the physical mechanisms at the origin of their occurrence are still intensively debated. Novel insights stem from recent results on the influence of the faulting style on the aftershock organisation in magnitude and time. Our study shows that the size of the aftershock zone depends on the fault geometry. We find that positive correlations among parameters controlling aftershock occurrence in time, energy and space are a stable feature of seismicity independently of magnitude range and geographic areas. We explain the ensemble of experimental findings by means of a description of the Earth Crust as an heterogeneous elastic medium coupled with a Maxwell viscoelastic asthenosphere. Our results show that heterogeneous stress distribution in an elastic layer combined with a coupling to a viscous flow are sufficient ingredients to describe the physics of aftershock triggering. PMID:26497720

  17. Origins of adaptive immunity.

    PubMed

    Liongue, Clifford; John, Liza B; Ward, Alister

    2011-01-01

    Adaptive immunity, involving distinctive antibody- and cell-mediated responses to specific antigens based on "memory" of previous exposure, is a hallmark of higher vertebrates. It has been argued that adaptive immunity arose rapidly, as articulated in the "big bang theory" surrounding its origins, which stresses the importance of coincident whole-genome duplications. Through a close examination of the key molecules and molecular processes underpinning adaptive immunity, this review suggests a less-extreme model, in which adaptive immunity emerged as part of longer evolutionary journey. Clearly, whole-genome duplications provided additional raw genetic materials that were vital to the emergence of adaptive immunity, but a variety of other genetic events were also required to generate some of the key molecules, whereas others were preexisting and simply co-opted into adaptive immunity. PMID:21395512

  18. Mechanical origin of aftershocks

    NASA Astrophysics Data System (ADS)

    Lippiello, E.; Giacco, F.; Marzocchi, W.; Godano, C.; de Arcangelis, L.

    2015-10-01

    Aftershocks are the most striking evidence of earthquake interactions and the physical mechanisms at the origin of their occurrence are still intensively debated. Novel insights stem from recent results on the influence of the faulting style on the aftershock organisation in magnitude and time. Our study shows that the size of the aftershock zone depends on the fault geometry. We find that positive correlations among parameters controlling aftershock occurrence in time, energy and space are a stable feature of seismicity independently of magnitude range and geographic areas. We explain the ensemble of experimental findings by means of a description of the Earth Crust as an heterogeneous elastic medium coupled with a Maxwell viscoelastic asthenosphere. Our results show that heterogeneous stress distribution in an elastic layer combined with a coupling to a viscous flow are sufficient ingredients to describe the physics of aftershock triggering.

  19. Origins of hydration lubrication

    NASA Astrophysics Data System (ADS)

    Ma, Liran; Gaisinskaya-Kipnis, Anastasia; Kampf, Nir; Klein, Jacob

    2015-01-01

    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4-1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication.

  20. The origins of informatics.

    PubMed Central

    Collen, M F

    1994-01-01

    This article summarizes the origins of informatics, which is based on the science, engineering, and technology of computer hardware, software, and communications. In just four decades, from the 1950s to the 1990s, computer technology has progressed from slow, first-generation vacuum tubes, through the invention of the transistor and its incorporation into microprocessor chips, and ultimately, to fast, fourth-generation very-large-scale-integrated silicon chips. Programming has undergone a parallel transformation, from cumbersome, first-generation, machine languages to efficient, fourth-generation application-oriented languages. Communication has evolved from simple copper wires to complex fiberoptic cables in computer-linked networks. The digital computer has profound implications for the development and practice of clinical medicine. PMID:7719803

  1. Conscientiousness: Origins in Childhood?

    PubMed Central

    Eisenberg, Nancy; Duckworth, Angela L.; Spinrad, Tracy L.; Valiente, Carlos

    2012-01-01

    In this review, we evaluate developmental and personality research with the aim of determining if the personality trait of conscientiousness can be identified in children and adolescents. After concluding that conscientiousness does emerge in childhood, we discuss the developmental origins of conscientiousness with a specific focus on self-regulation, academic motivation, and internalized compliance/internalization of standards. Based on the accumulated body of evidence, we conclude that self-regulation fosters conscientiousness later in life, both directly and via academic motivation and internalized compliance with norms. We argue that elements of conscientiousness are evident by early childhood, self-regulation skills are likely a core developmental component of conscientiousness, and despite the contribution of heredity to the aforementioned aspects of functioning, environmental factors likely contribute to conscientiousness. PMID:23244405

  2. Origins of hydration lubrication.

    PubMed

    Ma, Liran; Gaisinskaya-Kipnis, Anastasia; Kampf, Nir; Klein, Jacob

    2015-01-01

    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4-1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication. PMID:25585501

  3. Mechanical origin of aftershocks

    PubMed Central

    Lippiello, E.; Giacco, F.; Marzocchi, W.; Godano, C.; de Arcangelis, L.

    2015-01-01

    Aftershocks are the most striking evidence of earthquake interactions and the physical mechanisms at the origin of their occurrence are still intensively debated. Novel insights stem from recent results on the influence of the faulting style on the aftershock organisation in magnitude and time. Our study shows that the size of the aftershock zone depends on the fault geometry. We find that positive correlations among parameters controlling aftershock occurrence in time, energy and space are a stable feature of seismicity independently of magnitude range and geographic areas. We explain the ensemble of experimental findings by means of a description of the Earth Crust as an heterogeneous elastic medium coupled with a Maxwell viscoelastic asthenosphere. Our results show that heterogeneous stress distribution in an elastic layer combined with a coupling to a viscous flow are sufficient ingredients to describe the physics of aftershock triggering. PMID:26497720

  4. Actinides and Life's Origins

    NASA Astrophysics Data System (ADS)

    Adam, Zachary

    2007-12-01

    There are growing indications that life began in a radioactive beach environment. A geologic framework for the origin or support of life in a Hadean heavy mineral placer beach has been developed, based on the unique chemical properties of the lower-electronic actinides, which act as nuclear fissile and fertile fuels, radiolytic energy sources, oligomer catalysts, and coordinating ions (along with mineralogically associated lanthanides) for prototypical prebiotic homonuclear and dinuclear metalloenzymes. A four-factor nuclear reactor model was constructed to estimate how much uranium would have been required to initiate a sustainable fission reaction within a placer beach sand 4.3 billion years ago. It was calculated that about 1-8 weight percent of the sand would have to have been uraninite, depending on the weight percent, uranium enrichment, and quantity of neutron poisons present within the remaining placer minerals. Radiolysis experiments were conducted with various solvents with the use of uranium- and thorium-rich minerals (metatorbernite and monazite, respectively) as proxies for radioactive beach sand in contact with different carbon, hydrogen, oxygen, and nitrogen reactants. Radiation bombardment ranged in duration of exposure from 3 weeks to 6 months. Low levels of acetonitrile (estimated to be on the order of parts per billion in concentration) were conclusively identified in 2 setups and tentatively indicated in a 3rd by gas chromatography/mass spectrometry. These low levels have been interpreted within the context of a Hadean placer beach prebiotic framework to demonstrate the promise of investigating natural nuclear reactors as power production sites that might have assisted the origins of life on young rocky planets with a sufficiently differentiated crust/mantle structure. Future investigations are recommended to better quantify the complex relationships between energy release, radioactive grain size, fissionability, reactant phase, phosphorus

  5. Actinides and Life's Origins.

    PubMed

    Adam, Zachary

    2007-12-01

    There are growing indications that life began in a radioactive beach environment. A geologic framework for the origin or support of life in a Hadean heavy mineral placer beach has been developed, based on the unique chemical properties of the lower-electronic actinides, which act as nuclear fissile and fertile fuels, radiolytic energy sources, oligomer catalysts, and coordinating ions (along with mineralogically associated lanthanides) for prototypical prebiotic homonuclear and dinuclear metalloenzymes. A four-factor nuclear reactor model was constructed to estimate how much uranium would have been required to initiate a sustainable fission reaction within a placer beach sand 4.3 billion years ago. It was calculated that about 1-8 weight percent of the sand would have to have been uraninite, depending on the weight percent, uranium enrichment, and quantity of neutron poisons present within the remaining placer minerals. Radiolysis experiments were conducted with various solvents with the use of uraniumand thorium-rich minerals (metatorbernite and monazite, respectively) as proxies for radioactive beach sand in contact with different carbon, hydrogen, oxygen, and nitrogen reactants. Radiation bombardment ranged in duration of exposure from 3 weeks to 6 months. Low levels of acetonitrile (estimated to be on the order of parts per billion in concentration) were conclusively identified in 2 setups and tentatively indicated in a 3(rd) by gas chromatography/mass spectrometry. These low levels have been interpreted within the context of a Hadean placer beach prebiotic framework to demonstrate the promise of investigating natural nuclear reactors as power production sites that might have assisted the origins of life on young rocky planets with a sufficiently differentiated crust/mantle structure. Future investigations are recommended to better quantify the complex relationships between energy release, radioactive grain size, fissionability, reactant phase, phosphorus

  6. Origin of Sex Revisited

    NASA Astrophysics Data System (ADS)

    Santos, Mauro; Zintzaras, Elias; Szathmáry, Eörs

    2003-10-01

    Why did sex ever arise in the first place? Why it does not disappear in view of the greater efficiency of asexuals? These are clearly two different questions, and we suggest here that the solution for the origin of sex does not necessarily come from theoretical considerations based on currently existing genetic systems. Thus, while we agree with a number of authors in that the emergence of sex (understood as the exchange of genetic material between genomes) is deeply rooted in the origin of life and happened during the very early stages in the transition from individual genes (`replicators') to bacteria-like cells (`reproducers'), we challenge the idea that recombinational repair was the major selective force for the emergence of sex. Taking the stochastic corrector model as a starting point, we provide arguments that question the putative costs of redundancy in primitive protocells. In addition, if genes that cause intragenomic conflict (i.e., parasites) are taken into account, it is certainly wrong to suggest that cellular fusion would be beneficial at the population level (although this strong claim needs some qualifications). However, when a continuous input of deleterious mutations that impair the fitness of the protocell as a whole is considered in the model (in the realistic range in which stable mutant distributions of quasi-species within compartments are established), there are circumstances when sex could be beneficial as a side effect of the dynamic equilibrium between cellular fusion-mutation-selection. The scenario we have explored numerically is fully consistent with the idea that the universal ancestor was not a discrete entity but an ensemble of proto-organisms that exchanged much genetic information.

  7. Complete Sequence of pEC012, a Multidrug-Resistant IncI1 ST71 Plasmid Carrying blaCTX-M-65, rmtB, fosA3, floR, and oqxAB in an Avian Escherichia coli ST117 Strain

    PubMed Central

    Pan, Yu-Shan; Zong, Zhi-Yong; Yuan, Li; Du, Xiang-Dang; Huang, Hui; Zhong, Xing-Hao; Hu, Gong-Zheng

    2016-01-01

    A 139,622-bp IncI1 ST71 conjugative plasmid pEC012 from an avian Escherichia coli D-ST117 strain was sequenced, which carried five IS26-bracketed resistance modules: IS26-fosA3-orf1-orf2-Δorf3-IS26, IS26-fip-ΔISEcp1-blaCTX-M-65-IS903D-iroN-IS26, IS26-ΔtnpR-blaTEM-1-rmtB-IS26, IS26-oqxAB-IS26, and IS26-floR-aac(3)-IV-IS26. The backbone of pEC012 was similar to that of several other IncI1 ST71 plasmids: pV408, pM105, and pC271, but these plasmids had different arrangements of multidrug resistance region. In addition, the novel ISEc57 element was identified, which is in the IS21 family. The stepwise emergence of multi-resistance regions demonstrated the accumulation of different resistance determinants through homologous recombination. To the best of our knowledge, this is the first study to identify a multidrug-resistant IncI1 ST71 plasmid carrying blaCTX-M-65, rmtB, fosA3, floR, and oqxAB in an avian E. coli ST117 strain. PMID:27486449

  8. Complete Sequence of pEC012, a Multidrug-Resistant IncI1 ST71 Plasmid Carrying bla CTX-M-65, rmtB, fosA3, floR, and oqxAB in an Avian Escherichia coli ST117 Strain.

    PubMed

    Pan, Yu-Shan; Zong, Zhi-Yong; Yuan, Li; Du, Xiang-Dang; Huang, Hui; Zhong, Xing-Hao; Hu, Gong-Zheng

    2016-01-01

    A 139,622-bp IncI1 ST71 conjugative plasmid pEC012 from an avian Escherichia coli D-ST117 strain was sequenced, which carried five IS26-bracketed resistance modules: IS26-fosA3-orf1-orf2-Δorf3-IS26, IS26-fip-ΔISEcp1-bla CTX-M-65-IS903D-iroN-IS26, IS26-ΔtnpR-bla TEM-1-rmtB-IS26, IS26-oqxAB-IS26, and IS26-floR-aac(3)-IV-IS26. The backbone of pEC012 was similar to that of several other IncI1 ST71 plasmids: pV408, pM105, and pC271, but these plasmids had different arrangements of multidrug resistance region. In addition, the novel ISEc57 element was identified, which is in the IS21 family. The stepwise emergence of multi-resistance regions demonstrated the accumulation of different resistance determinants through homologous recombination. To the best of our knowledge, this is the first study to identify a multidrug-resistant IncI1 ST71 plasmid carrying bla CTX-M-65, rmtB, fosA3, floR, and oqxAB in an avian E. coli ST117 strain. PMID:27486449

  9. The Origin of Alcohol Proof

    ERIC Educational Resources Information Center

    Jensen, William B.

    2004-01-01

    The origin of the "proof" system for measuring the ethanol content of alcoholic beverages is presented. The proof system was originally established for purposes of taxing liquors according to their alcohol content and is different in different countries.

  10. Origins of GEMS Grains

    NASA Technical Reports Server (NTRS)

    Messenger, S.; Walker, R. M.

    2012-01-01

    Interplanetary dust particles (IDPs) collected in the Earth s stratosphere contain high abundances of submicrometer amorphous silicates known as GEMS grains. From their birth as condensates in the outflows of oxygen-rich evolved stars, processing in interstellar space, and incorporation into disks around new stars, amorphous silicates predominate in most astrophysical environments. Amorphous silicates were a major building block of our Solar System and are prominent in infrared spectra of comets. Anhydrous interplanetary dust particles (IDPs) thought to derive from comets contain abundant amorphous silicates known as GEMS (glass with embedded metal and sulfides) grains. GEMS grains have been proposed to be isotopically and chemically homogenized interstellar amorphous silicate dust. We evaluated this hypothesis through coordinated chemical and isotopic analyses of GEMS grains in a suite of IDPs to constrain their origins. GEMS grains show order of magnitude variations in Mg, Fe, Ca, and S abundances. GEMS grains do not match the average element abundances inferred for ISM dust containing on average, too little Mg, Fe, and Ca, and too much S. GEMS grains have complementary compositions to the crystalline components in IDPs suggesting that they formed from the same reservoir. We did not observe any unequivocal microstructural or chemical evidence that GEMS grains experienced prolonged exposure to radiation. We identified four GEMS grains having O isotopic compositions that point to origins in red giant branch or asymptotic giant branch stars and supernovae. Based on their O isotopic compositions, we estimate that 1-6% of GEMS grains are surviving circumstellar grains. The remaining 94-99% of GEMS grains have O isotopic compositions that are indistinguishable from terrestrial materials and carbonaceous chondrites. These isotopically solar GEMS grains either formed in the Solar System or were completely homogenized in the interstellar medium (ISM). However, the

  11. Gould Belt Origin

    NASA Astrophysics Data System (ADS)

    Rivera, Leticia; Loinard, Laurent; Dzib, Sergio

    2013-07-01

    Using archive VLA data and recent observations on the Karl G. Jansky Very Large Array it is worked on a semi-automatic python/CASA code to select, reduce and plot several young stars belonging to the Ophiuchus core. This code mean to help to select observations made along the 30 years of the VLA done in the selected area with the wide configurations A and B, and in the X and C band, to determine their position and compare it with the most recent ones. In this way it is possible to determinate their proper motion with very high precision. It is presented the phases of the process and our first results worked on three well know stars: S1, DoAr 21 and VLA1623. This is the tip of a bigger work that includes Taurus molecular cloud and other important recent star formation regions belonging to the Gould Belt. Our goal is to support the most suitable among several theories about Gould Belt origin or provide a new one taking in count the dynamics of those regions.

  12. Eusociality: Origin and consequences

    PubMed Central

    Wilson, Edward O.; Hölldobler, Bert

    2005-01-01

    In this new assessment of the empirical evidence, an alternative to the standard model is proposed: group selection is the strong binding force in eusocial evolution; individual selection, the strong dissolutive force; and kin selection (narrowly defined), either a weak binding or weak dissolutive force, according to circumstance. Close kinship may be more a consequence of eusociality than a factor promoting its origin. A point of no return to the solitary state exists, as a rule when workers become anatomically differentiated. Eusociality has been rare in evolution, evidently due to the scarcity of environmental pressures adequate to tip the balance among countervailing forces in favor of group selection. Eusociality in ants and termites in the irreversible stage is the key to their ecological dominance and has (at least in ants) shaped some features of internal phylogeny. Their colonies are consistently superior to solitary and preeusocial competitors, due to the altruistic behavior among nestmates and their ability to organize coordinated action by pheromonal communication. PMID:16157878

  13. Origin of Neutron Stars

    NASA Astrophysics Data System (ADS)

    Brecher, K.

    1999-12-01

    The origin of the concept of neutron stars can be traced to two brief, incredibly insightful publications. Work on the earlier paper by Lev Landau (Phys. Z. Sowjetunion, 1, 285, 1932) actually predated the discovery of neutrons. Nonetheless, Landau arrived at the notion of a collapsed star with the density of a nucleus (really a "nucleus star") and demonstrated (at about the same time as, and independent of, Chandrasekhar) that there is an upper mass limit for dense stellar objects of about 1.5 solar masses. Perhaps even more remarkable is the abstract of a talk presented at the December 1933 meeting of the American Physical Society published by Walter Baade and Fritz Zwicky in 1934 (Phys. Rev. 45, 138). It followed the discovery of the neutron by just over a year. Their report, which was about the same length as the present abstract: (1) invented the concept and word supernova; (2) suggested that cosmic rays are produced by supernovae; and (3) in the authors own words, proposed "with all reserve ... the view that supernovae represent the transitions from ordinary stars to neutron stars (italics), which in their final stages consist of extremely closely packed neutrons." The abstract by Baade and Zwicky probably contains the highest density of new, important (and correct) ideas in high energy astrophysics ever published in a single paper. In this talk, we will discuss some of the facts and myths surrounding these two publications.

  14. Origins of magnetospheric physics

    SciTech Connect

    Van Allen, J.A.

    1983-01-01

    The history of the scientific investigation of the earth magnetosphere during the period 1946-1960 is reviewed, with a focus on satellite missions leading to the discovery of the inner and outer radiation belts. Chapters are devoted to ground-based studies of the earth magnetic field through the 1930s, the first U.S. rocket flights carrying scientific instruments, the rockoon flights from the polar regions (1952-1957), U.S. planning for scientific use of artificial satellites (1956), the launch of Sputnik I (1957), the discovery of the inner belt by Explorers I and III (1958), the Argus high-altitude atomic-explosion tests (1958), the confirmation of the inner belt and discovery of the outer belt by Explorer IV and Pioneers I-V, related studies by Sputniks II and III and Luniks I-III, and the observational and theoretical advances of 1959-1961. Photographs, drawings, diagrams, graphs, and copies of original notes and research proposals are provided. 227 references.

  15. DHCP Origin Traceback

    NASA Astrophysics Data System (ADS)

    Majumdar, Saugat; Kulkarni, Dhananjay; Ravishankar, Chinya V.

    Imagine that the DHCP server is under attack from malicious hosts in your network. How would you know where these DHCP packets are coming from, or which path they took in the network? This paper investigates the problem of determining the origin of a DHCP packet in a network. We propose a practical method for adding a new option field that does not violate any RFC's, which we believe should be a crucial requirement while proposing any related solution. The new DHCP option will contain the ingress port and the switch MAC address. We recommend that this new option be added at the edge so that we can use the recorded value for performing traceback. The computational overhead of our solution is low, and the related network management tasks are low as well. We also address issues related to securing the field in order to maintain privacy of switch MAC addresses, fragmentation of packets, and possible attack scenarios. Our study shows that the traceback scheme is effective and practical to use in most network environments.

  16. DNA replication origins in archaea

    PubMed Central

    Wu, Zhenfang; Liu, Jingfang; Yang, Haibo; Xiang, Hua

    2014-01-01

    DNA replication initiation, which starts at specific chromosomal site (known as replication origins), is the key regulatory stage of chromosome replication. Archaea, the third domain of life, use a single or multiple origin(s) to initiate replication of their circular chromosomes. The basic structure of replication origins is conserved among archaea, typically including an AT-rich unwinding region flanked by several conserved repeats (origin recognition box, ORB) that are located adjacent to a replication initiator gene. Both the ORB sequence and the adjacent initiator gene are considerably diverse among different replication origins, while in silico and genetic analyses have indicated the specificity between the initiator genes and their cognate origins. These replicator–initiator pairings are reminiscent of the oriC-dnaA system in bacteria, and a model for the negative regulation of origin activity by a downstream cluster of ORB elements has been recently proposed in haloarchaea. Moreover, comparative genomic analyses have revealed that the mosaics of replicator-initiator pairings in archaeal chromosomes originated from the integration of extrachromosomal elements. This review summarizes the research progress in understanding of archaeal replication origins with particular focus on the utilization, control and evolution of multiple replication origins in haloarchaea. PMID:24808892

  17. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2014-05-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. . As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  18. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2015-04-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. . As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  19. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2016-04-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. . As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  20. THE COSMIC ORIGINS SPECTROGRAPH

    SciTech Connect

    Green, James C.; Michael Shull, J.; Snow, Theodore P.; Stocke, John; Froning, Cynthia S.; Osterman, Steve; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Sembach, Kenneth; Linsky, Jeffrey L.; Savage, Blair D.; Siegmund, Oswald H. W.; Spencer, John; Alan Stern, S.; Welsh, Barry; and others

    2012-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in 2009 May, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F{sub {lambda}} Almost-Equal-To 1.0 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} A{sup -1}, COS can achieve comparable signal to noise (when compared to Space Telescope Imaging Spectrograph echelle modes) in 1%-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (2009 September-2011 June) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is nine times than sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of 2011 June. COS has measured, for the first time with high reliability, broad Ly{alpha} absorbers and Ne VIII in the intergalactic medium, and observed the He II reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  1. The Cosmic Origins Spectrograph

    NASA Technical Reports Server (NTRS)

    Green, James C.; Froning, Cynthia S.; Osterman, Steve; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Linsky, Jeffrey L.; Savage, Blair D.; Sembach, Kenneth; Shull, J. Michael; Siegmund, Oswald H. W.; Snow, Theodore P.; Spencer, John; Stern, S. Alan; Stocke, John; Welsh, Barry; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin; Keeney, Brian; McPhate, Jason; Penton, Steven V; Andrews, John; Morse, Jon

    2010-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F(sub lambda) approximates 1.0 X 10(exp -14) ergs/s/cm2/Angstrom, COS can achieve comparable signal to noise (when compared to STIS echelle modes) in 1-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (September 2009 - June 2011) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is 9 times that sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of June 2011. COS has measured, for the first time with high reliability, broad Lya absorbers and Ne VIII in the intergalactic medium, and observed the HeII reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  2. "Origin," "creation," and "origin of life" some conceptual considerations.

    PubMed

    Charpa, Ulrich

    2012-01-01

    This paper opens by drawing attention to the fact that there is some conceptual confusion with regard to "origin" and "creation." This has its historical roots in the beginnings of modern science and undoubtedly affects our positioning towards the evolutionism/creationism-debate. This article argues that there are relevant ontological, epistemological, thematic, methodological, and logical differences between "origin" and "creation." As a result, the analysis suggests keeping the usage of both concepts strictly quite separate. Creation is not simply another word for origin nor does it stand for an (from a rigid scientific point of view) awkward example of an origin. Irrespective of the apparent similarities as explanatory factors, origin and creation belong to fundamentally different types of concepts. Consequently, "origin of life" and those scientific projects connected to it present themselves as something distinct that neither competes nor meshes with thinking about creation. PMID:23316571

  3. Generating original ideas: The neural underpinning of originality.

    PubMed

    Mayseless, Naama; Eran, Ayelet; Shamay-Tsoory, Simone G

    2015-08-01

    One of the key aspects of creativity is the ability to produce original ideas. Originality is defined in terms of the novelty and rarity of an idea and is measured by the infrequency of the idea compared to other ideas. In the current study we focused on divergent thinking (DT) - the ability to produce many alternate ideas - and assessed the neural pathways associated with originality. Considering that generation of original ideas involves both the ability to generate new associations and the ability to overcome automatic common responses, we hypothesized that originality would be associated with activations in regions related to associative thinking, including areas of the default mode network (DMN) such as medial prefrontal areas, as well as with areas involved in cognitive control and inhibition. Thirty participants were scanned while performing a DT task that required the generation of original uses for common objects. The results indicate that the ability to produce original ideas is mediated by activity in several regions that are part of the DMN including the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC). Furthermore, individuals who are more original exhibited enhanced activation in the ventral anterior cingulate cortex (vACC), which was also positively coupled with activity in the left occipital-temporal area. These results are in line with the dual model of creativity, according to which original ideas are a product of the interaction between a system that generates ideas and a control system that evaluates these ideas. PMID:26003860

  4. 56. Photograph of Original Plan (original plans in the possession ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. Photograph of Original Plan (original plans in the possession of the Los Angeles Union Passenger Terminal Corporation) BAGGAGE AND EXPRESS UNIT, MAIN FLOOR AND BOILER ROOM PLANS, SECTIONS IV-V - Los Angeles Union Passenger Terminal, Tracks & Shed, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  5. 55. Photograph of Original Plan (original plans in the possession ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    55. Photograph of Original Plan (original plans in the possession of the Los Angeles Union Passenger Terminal Corporation) BAGGAGE AND EXPRESS UNITY, STREET LEVEL FLOOR PLAN, SECTION III - Los Angeles Union Passenger Terminal, Tracks & Shed, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  6. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-22), showing current floor plan. Department of the Navy, Bureau of Yards and Docks, "Record drawing, N.D. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  7. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-4, showing organ recess. Dept. yards & docks, U.S. Navy, Mare Island, Cal., "Plan & Sections, proposed addition, St. Peter's Chapel, December 1904 - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  8. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-5). Depts. Yards & docks, U.S. Navy Mare Island, Cal., "full sized detail of fretwork panels in back of organ recess, St. Peter's Chapel, Mare Island, Cal., December 1904. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  9. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-7. "Full size sketch of 2 candelabra stands for St. Peters Chapel, Mare Island, Calif.," October 1908. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  10. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-14). Dept. of yards and docks, "Chapel amplifier support," October 1945. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  11. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-1), showing ground plan. Albert Sutton, plan for yard chapel at U.S. Navy Yard, Mare Island, Cal., November 1900. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  12. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-2), showing front elevation and section. Albert Sutton, plan for yard chapel at U.S. Navy Yard, Mare Island, Cal., November 1900. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  13. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-3, showing side and rear elevation. Albert Sutton, "plan for yard chapel at the U.S. Navy Yard, Mare Island, Cal.," November 1900. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  14. 16. Photocopy of original USRS photograph (from original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Photocopy of original USRS photograph (from original print in the Umatilla Project History 1918, on file at National Archives, Rocky Mountain Region, Denver, Colorado) Photographer unknown, ca. 1918. Office of U.S. Reclamation Service - Hermiston, Umatilla Project, Oregon - Former Umatilla Project Headquarters Buildings, Office, Hermiston, Umatilla County, OR

  15. Photograph of original drawing (original in possession of National Passenger ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photograph of original drawing (original in possession of National Passenger Railroad Corporation). STATION BUILDING: Foundation Plan / Alterations and Additions (dated: 7/17/14) - North Philadelphia Station, 2900 North Broad Street, on northwest corner of Broad Street & Glenwood Avenue, Philadelphia, Philadelphia County, PA

  16. 12. Photocopy of original construction drawing, dated November 1932 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Photocopy of original construction drawing, dated November 1932 (original print in possession of Veterans Administration, Oakland Branch, Pittsburgh, Pennsylvania). DRAWING 32-2 -- ADMINISTRATION BUILDING, BUILDING NO. 32 -- BASEMENT PLAN AND CUPOLA DETAIL. - VA Medical Center, Aspinwall Division, Administration Building, 5103 Delafield Avenue, Aspinwall, Allegheny County, PA

  17. 13. Photocopy of original construction drawing, dated November 1932 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Photocopy of original construction drawing, dated November 1932 (original print in possession of Veterans Administration, Oakland Branch, Pittsburgh, Pennsylvania). DRAWING 32-3 -- ADMINISTRATION BUILDING, BUILDING NO. 32 -- FIRST AND SECOND FLOOR PLANS. - VA Medical Center, Aspinwall Division, Administration Building, 5103 Delafield Avenue, Aspinwall, Allegheny County, PA

  18. 25. Photocopy of Original Drawing (original in the State of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. Photocopy of Original Drawing (original in the State of Michigan Record Center) FALSEWORK DETAILS, TYPICAL HALF ELEVATION OF AN INTERIOR RIB, SECTION NEAR END OF SPAN, AND SECTION NEAR PIER - Monroe Street Bridge, Spanning River Raisin at Monroe Street, Monroe, Monroe County, MI

  19. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # A-21). Dept. of the Navy District Public Works Office, "additions, floor plan, elevations & details; architectural, mechanical & electrical," May 1963. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  20. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-25) William Jeffries Associates, A.I.A., "Repair to stained glass window, building 104, elevation & details," September 1952. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  1. 21. Photocopy of Original Drawing (original in Michigan Department of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. Photocopy of Original Drawing (original in Michigan Department of Transportation, 425 West Ottawa, Lansing, MI 48909), Bridge X2 of 11-2-21, Sheet 9, July 23, 1935. EAST ELEVATION, LOOKING WEST - State Route M-139 Bridge, Spanning Ox Creek, Fair Plain, Berrien County, MI

  2. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-9). (Signed) Ralph Whitman, public works officer, "Yard chapel addition to house organ, etc., plans, elevations, details," September 1929. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  3. Photocopy of original drawings (original located at the National Archives, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-13). (Signed) Ralph Whitman, public works officer, "Yard chapel organ addition mill details, exterior window," September 1929. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  4. 8. Photocopy of original USRS glass plate slide (from original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Photocopy of original USRS glass plate slide (from original slide on file at National Archives, Rocky Mountain Region, Denver, Colorado) Photographer unknown, ca. 1908 The diversion weir of the Okanogan National Irrigation Project - Salmon Creek Diversion Dam, Salmon Creek, Okanogan, Okanogan County, WA

  5. 11. Photocopy of original construction drawing, dated 1934. (Original print ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Photocopy of original construction drawing, dated 1934. (Original print in the possession of U.S. Army Corps of Engineers, Portland District, Portland, OR.) ADMINISTRATION BUILDING MAIN FLOOR PLAN. - Bonneville Project, Administration Building, South side of main entrance, Bonneville Project, Bonneville, Multnomah County, OR

  6. 12. Photocopy of original construction drawing, undated. (Original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Photocopy of original construction drawing, undated. (Original print in the possession of U.S. Army Corps of Engineers, Portland District, Portland, OR.) PROPOSED EXTENSION TO ADMINISTRATION BUILDING. - Bonneville Project, Administration Building, South side of main entrance, Bonneville Project, Bonneville, Multnomah County, OR

  7. 58. Photograph of Original Plan (original plans in the possession ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    58. Photograph of Original Plan (original plans in the possession of the Los Angeles Union Passenger Terminal Corporation) BAGGAGE AND EXPRESS UNIT, ELEVATIONS AND SECTIONS, SECTION IV-V - Los Angeles Union Passenger Terminal, Tracks & Shed, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  8. 19. Photocopy of original construction drawing, dated April 1924 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Photocopy of original construction drawing, dated April 1924 (original print in possession of Veterans Administration, Oakland Branch, Pittsburgh, Pennsylvania). DRAWING 1-1 -- INFIRMARY, BUILDING NO. 1 -- CENTER PORTION -- BASEMENT PLAN. - VA Medical Center, Aspinwall Division, Infirmary Building, 5103 Delafield Avenue (O'Hara Township), Aspinwall, Allegheny County, PA

  9. 29. Photocopy of original construction drawing, dated February 1932 (original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. Photocopy of original construction drawing, dated February 1932 (original print in possession of Veterans Administration, Oakland Branch, Pittsburgh, Pennsylvania). DRAWING 1-1 -- INFIRMARY, BUILDING NO. 1 -- ADDITION TO INFIRMARY -- BASEMENT PLAN. - VA Medical Center, Aspinwall Division, Infirmary Building, 5103 Delafield Avenue (O'Hara Township), Aspinwall, Allegheny County, PA

  10. Photocopy of photograph (original located at Mare Island Archives). Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Dry dock 2 with three submarines and one sailing ship; 1914. - Mare Island Naval Shipyard, Drydock No. 2, California Avenue, east side near Ninth Street, Vallejo, Solano County, CA

  11. 114. Photocopy of original construction drawing, 14 August 1935. (Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    114. Photocopy of original construction drawing, 14 August 1935. (Original print in the possession of U.S. Army Corps of Engineers, Portland District, Portland, OR.) (M-5-8, Sheet No. 14) SPILLWAY DAM FISHWAY ENTRANCE BAY DIFFUSION CHAMBER BEAN DETAILS. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  12. CTX-M Enzymes: Origin and Diffusion

    PubMed Central

    Cantón, Rafael; González-Alba, José María; Galán, Juan Carlos

    2012-01-01

    CTX-M β-lactamases are considered a paradigm in the evolution of a resistance mechanism. Incorporation of different chromosomal blaCTX-M related genes from different species of Kluyvera has derived in different CTX-M clusters. In silico analyses have shown that this event has occurred at least nine times; in CTX-M-1 cluster (3), CTX-M-2 and CTX-M-9 clusters (2 each), and CTX-M-8 and CTX-M-25 clusters (1 each). This has been mainly produced by the participation of genetic mobilization units such as insertion sequences (ISEcp1 or ISCR1) and the later incorporation in hierarchical structures associated with multifaceted genetic structures including complex class 1 integrons and transposons. The capture of these blaCTX-M genes from the environment by highly mobilizable structures could have been a random event. Moreover, after incorporation within these structures, β-lactam selective force such as that exerted by cefotaxime and ceftazidime has fueled mutational events underscoring diversification of different clusters. Nevertheless, more variants of CTX-M enzymes, including those not inhibited by β-lactamase inhibitors such as clavulanic acid (IR-CTX-M variants), only obtained under in in vitro experiments, are still waiting to emerge in the clinical setting. Penetration and the later global spread of CTX-M producing organisms have been produced with the participation of the so-called “epidemic resistance plasmids” often carried in multi-drug resistant and virulent high-risk clones. All these facts but also the incorporation and co-selection of emerging resistance determinants within CTX-M producing bacteria, such as those encoding carbapenemases, depict the currently complex pandemic scenario of multi-drug resistant isolates. PMID:22485109

  13. Editing Paperback Reprints and Originals.

    ERIC Educational Resources Information Center

    Feiwel, Janet

    1982-01-01

    Outlines the functions of an editor of paperback reprint and original children's books at Avon Books, describes the strategies that go into the selection of books for paperback reprinting or original publication, and reviews the approaches to marketing paperback children's books, such as cover art, which distinguish them from hardcovers. (JL)

  14. The Origins of Soviet Sociolinguistics.

    ERIC Educational Resources Information Center

    Brandist, Craig

    2003-01-01

    Discusses the origins of Soviet sociolinguistics and suggests that the historical significance of the reception and reinterpretation of these ideas is considerable, leading to a reconsideration of the origins of sociolinguistics and the relationship between Marxism and the language sciences in the early years of the Soviet Union. (Author/VWL)

  15. The Origin of Malignant Malaria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plasmodium falciparum is the causative agent of malignant malaria, which is among the most severe human infectious diseases. Despite its overwhelming significance to human health, the parasite’s origins remain unclear. The favored origin hypothesis holds that P. falciparum and its closest known rel...

  16. 17. Photocopy of original USRS photograph (from original print in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Photocopy of original USRS photograph (from original print in the Umatilla Project History 1920, on file at National Archives, Rocky Mountain Region, Denver, Colorado) Photographer unknown, ca. 1920. Project office and employees - reading from left to right: Una H. Keck, Geo. C. Patterson, H.M. Schilling, Maurice D. Scroggs, Carl M. Voyen, Chas. Taylor, C.D. Porter - Former Umatilla Project Headquarters Buildings, Office, Hermiston, Umatilla County, OR

  17. The origins of originality: the neural bases of creative thinking and originality.

    PubMed

    Shamay-Tsoory, S G; Adler, N; Aharon-Peretz, J; Perry, D; Mayseless, N

    2011-01-01

    Although creativity has been related to prefrontal activity, recent neurological case studies postulate that patients who have left frontal and temporal degeneration involving deterioration of language abilities may actually develop de novo artistic abilities. In this study, we propose a neural and cognitive model according to which a balance between the two hemispheres affects a major aspect of creative cognition, namely, originality. In order to examine the neural basis of originality, that is, the ability to produce statistically infrequent ideas, patients with localized lesions in the medial prefrontal cortex (mPFC), inferior frontal gyrus (IFG), and posterior parietal and temporal cortex (PC), were assessed by two tasks involving divergent thinking and originality. Results indicate that lesions in the mPFC involved the most profound impairment in originality. Furthermore, precise anatomical mapping of lesions indicated that while the extent of lesion in the right mPFC was associated with impaired originality, lesions in the left PC were associated with somewhat elevated levels of originality. A positive correlation between creativity scores and left PC lesions indicated that the larger the lesion is in this area the greater the originality. On the other hand, a negative correlation was observed between originality scores and lesions in the right mPFC. It is concluded that the right mPFC is part of a right fronto-parietal network which is responsible for producing original ideas. It is possible that more linear cognitive processing such as language, mediated by left hemisphere structures interferes with creative cognition. Therefore, lesions in the left hemisphere may be associated with elevated levels of originality. PMID:21126528

  18. Origines de la nomenclature astrale

    NASA Astrophysics Data System (ADS)

    Duchesne-Guillemin, J.

    Within a survey of the Indo-European, Sumero-Babylonian, Greek, Arabic, and modern origins of the names of the constellations, stars, planets, satellites, asteroids, etc., an explanation is offered of the Omega sign used in Greek horoscopes for the lunar nodes but already appearing on Babylonian reliefs. Its origin is traced back to the Sumerian constellations of the Yoke, later called the Dragon.

  19. Origin of the sinus impulse.

    PubMed

    Schuessler, R B; Boineau, J P; Bromberg, B I

    1996-03-01

    It was generally accepted that the site of normal impulse origin within the atria was a single static focus within the sinus node. This review will examine how this model of impulse origin came about and has evolved. Early on, conflicting data suggested that the sinus node focus was not static and changed with interventions that changed heart rate, such as vagal stimulation. Furthermore, even with removal of the sinus node, a normal atrial rhythm was generated. High-resolution mapping in humans and dogs showed that the initiation of the impulse was dynamic and could be multicentric, with more than one focus initiating a single beat. Shifts in the site of origin correlated with changes in rate and were consistent with P wave changes routinely observed in the standard ECG. These studies suggested multiple pacemakers were responsible for impulse initiation. However, it was not clear how these widespread pacemakers were coordinated to function synchronously. Recent canine data suggest that the node may be partially insulated from the surrounding atrium, resulting in multicentric origin starting from a single site within the node. What has evolved is a model of impulse origin with a sinus node having discrete exit sites and a dominant pacemaker within the node that can shift to other nodal sites. Complex and changing conduction out of the node, coupled with extranodal pacemakers, which can assume dominance over the node, combine with the autonomic nervous system to control heart rate and the pattern of impulse origin within the atria. PMID:8867301

  20. The origins of research into the origins of life.

    PubMed

    Fry, Iris

    2006-03-01

    Most scientists at the end of the 19th and the beginning of the 20th century chose to ignore the question of the origin of life on Earth, regarding it as too mysterious and complex to handle. Yet, in the early 1950s an experimental field devoted to the study of the problem made its first steps. The pioneering theories of several scientists in the first decades of the 20th century played a major role in this transformation, notably those of the Russian biochemist Alexander I. Oparin and the British geneticist and biochemist J.B.S. Haldane. The ideas of the lesser-known American psycho-physiologist Leonard Troland also made a significant contribution to subsequent developments in origin-of-life research. Therefore, it is well worth taking a look at the professional, philosophical and ideological commitments that shaped the approaches of the three scientists to origin-of-life research. PMID:16469383

  1. Endosymbiotic theories for eukaryote origin

    PubMed Central

    Martin, William F.; Garg, Sriram; Zimorski, Verena

    2015-01-01

    For over 100 years, endosymbiotic theories have figured in thoughts about the differences between prokaryotic and eukaryotic cells. More than 20 different versions of endosymbiotic theory have been presented in the literature to explain the origin of eukaryotes and their mitochondria. Very few of those models account for eukaryotic anaerobes. The role of energy and the energetic constraints that prokaryotic cell organization placed on evolutionary innovation in cell history has recently come to bear on endosymbiotic theory. Only cells that possessed mitochondria had the bioenergetic means to attain eukaryotic cell complexity, which is why there are no true intermediates in the prokaryote-to-eukaryote transition. Current versions of endosymbiotic theory have it that the host was an archaeon (an archaebacterium), not a eukaryote. Hence the evolutionary history and biology of archaea increasingly comes to bear on eukaryotic origins, more than ever before. Here, we have compiled a survey of endosymbiotic theories for the origin of eukaryotes and mitochondria, and for the origin of the eukaryotic nucleus, summarizing the essentials of each and contrasting some of their predictions to the observations. A new aspect of endosymbiosis in eukaryote evolution comes into focus from these considerations: the host for the origin of plastids was a facultative anaerobe. PMID:26323761

  2. Endosymbiotic theories for eukaryote origin.

    PubMed

    Martin, William F; Garg, Sriram; Zimorski, Verena

    2015-09-26

    For over 100 years, endosymbiotic theories have figured in thoughts about the differences between prokaryotic and eukaryotic cells. More than 20 different versions of endosymbiotic theory have been presented in the literature to explain the origin of eukaryotes and their mitochondria. Very few of those models account for eukaryotic anaerobes. The role of energy and the energetic constraints that prokaryotic cell organization placed on evolutionary innovation in cell history has recently come to bear on endosymbiotic theory. Only cells that possessed mitochondria had the bioenergetic means to attain eukaryotic cell complexity, which is why there are no true intermediates in the prokaryote-to-eukaryote transition. Current versions of endosymbiotic theory have it that the host was an archaeon (an archaebacterium), not a eukaryote. Hence the evolutionary history and biology of archaea increasingly comes to bear on eukaryotic origins, more than ever before. Here, we have compiled a survey of endosymbiotic theories for the origin of eukaryotes and mitochondria, and for the origin of the eukaryotic nucleus, summarizing the essentials of each and contrasting some of their predictions to the observations. A new aspect of endosymbiosis in eukaryote evolution comes into focus from these considerations: the host for the origin of plastids was a facultative anaerobe. PMID:26323761

  3. A Hubble Space Telescope/Cosmic Origins Spectrograph Search for Warm-hot Baryons in the Mrk 421 Sight Line

    NASA Astrophysics Data System (ADS)

    Danforth, Charles W.; Stocke, John T.; Keeney, Brian A.; Penton, Steven V.; Shull, J. Michael; Yao, Yangsen; Green, James C.

    2011-12-01

    Thermally broadened Lyα absorbers (BLAs) offer an alternate method to using highly ionized metal absorbers (O VI, O VII, etc.) to probe the warm-hot intergalactic medium (WHIM, T = 105-107 K). Until now, WHIM surveys via BLAs have been no less ambiguous than those via far-UV and X-ray metal-ion probes. Detecting these weak, broad features requires background sources with a well-characterized far-UV continuum and data of very high quality. However, a recent Hubble Space Telescope/Cosmic Origins Spectrograph (COS) observation of the z = 0.03 blazar Mrk 421 allows us to perform a metal-independent search for WHIM gas with unprecedented precision. The data have high signal-to-noise ratio (S/N ≈ 50 per ~20 km s-1 resolution element) and the smooth, power-law blazar spectrum allows a fully parametric continuum model. We analyze the Mrk 421 sight line for BLA absorbers, particularly for counterparts to the proposed O VII WHIM systems reported by Nicastro et al. based on Chandra/Low Energy Transmission Grating observations. We derive the Lyα profiles predicted by the X-ray observations. The S/N of the COS data is high (S/N ≈ 25 pixel-1), but much higher S/N can be obtained by binning the data to widths characteristic of the expected BLA profiles. With this technique, we are sensitive to WHIM gas over a large (N H, T) parameter range in the Mrk 421 sight line. We rule out the claimed Nicastro et al. O VII detections at their nominal temperatures (T ~ 1-2 × 106 K) and metallicities (Z = 0.1 Z ⊙) at >~ 2σ level. However, WHIM gas at higher temperatures and/or higher metallicities is consistent with our COS non-detections. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS5-26555.

  4. A HUBBLE SPACE TELESCOPE/COSMIC ORIGINS SPECTROGRAPH SEARCH FOR WARM-HOT BARYONS IN THE Mrk 421 SIGHT LINE

    SciTech Connect

    Danforth, Charles W.; Stocke, John T.; Keeney, Brian A.; Penton, Steven V.; Shull, J. Michael; Yao Yangsen; Green, James C.

    2011-12-10

    Thermally broadened Ly{alpha} absorbers (BLAs) offer an alternate method to using highly ionized metal absorbers (O VI, O VII, etc.) to probe the warm-hot intergalactic medium (WHIM, T = 10{sup 5}-10{sup 7} K). Until now, WHIM surveys via BLAs have been no less ambiguous than those via far-UV and X-ray metal-ion probes. Detecting these weak, broad features requires background sources with a well-characterized far-UV continuum and data of very high quality. However, a recent Hubble Space Telescope/Cosmic Origins Spectrograph (COS) observation of the z = 0.03 blazar Mrk 421 allows us to perform a metal-independent search for WHIM gas with unprecedented precision. The data have high signal-to-noise ratio (S/N Almost-Equal-To 50 per {approx}20 km s{sup -1} resolution element) and the smooth, power-law blazar spectrum allows a fully parametric continuum model. We analyze the Mrk 421 sight line for BLA absorbers, particularly for counterparts to the proposed O VII WHIM systems reported by Nicastro et al. based on Chandra/Low Energy Transmission Grating observations. We derive the Ly{alpha} profiles predicted by the X-ray observations. The S/N of the COS data is high (S/N Almost-Equal-To 25 pixel{sup -1}), but much higher S/N can be obtained by binning the data to widths characteristic of the expected BLA profiles. With this technique, we are sensitive to WHIM gas over a large (N{sub H}, T) parameter range in the Mrk 421 sight line. We rule out the claimed Nicastro et al. O VII detections at their nominal temperatures (T {approx} 1-2 Multiplication-Sign 10{sup 6} K) and metallicities (Z = 0.1 Z{sub Sun }) at {approx}> 2{sigma} level. However, WHIM gas at higher temperatures and/or higher metallicities is consistent with our COS non-detections.

  5. The origin of the moon.

    PubMed

    Boss, A P

    1986-01-24

    The origin of the moon is considered within the theory of formation of the terrestrial planets by accumulation of planetesimals. The theory predicts the occurrence of giant impacts, suggesting that the moon formed after a roughly Mars-sized body impacted on the protoearth. The impact blasted portions of the protoearth and the impacting body into geocentric orbit, forming a prelunar disk from which the moon later accreted. Although other mechanisms for formation of the moon appear to be dynamically impossible or implausible, fundamental questions must be answered before a giant impact origin can be considered both possible and probable. PMID:17735007

  6. The Origin of Roman Numerals

    ERIC Educational Resources Information Center

    Dapre, P. A.

    1977-01-01

    A theory on the origin of Roman numerals proposes that the principal numbers can be stylized in terms of a square. It is speculated that the abacus or its equivalents, such as the counter or chequer-board, was used to count before the alphabet became common. (SW)

  7. The Moon and Its Origin

    ERIC Educational Resources Information Center

    Urey, Harold C.

    1973-01-01

    Describes the origin of the Moon on the basis of the Apollo expeditions as an accumulated gas sphere at its very beginning and, later, a satellite captured by the Earth. Indicates that the model would be substantially believable if further observations should be proved to exist as estimated. (CC)

  8. Origin of Water on Mars

    NASA Technical Reports Server (NTRS)

    Lunine, J. I.; Morbidelli, A.; Chambers, J. E.

    2002-01-01

    Dynamical simulations suggest that the Earth's water budget was delivered primarily from the asteroid belt, in the form of large planetary embryos. The same simulations present a very different picture for Mars its water came from a mixture of cometary and small asteroidal bodies. Additional information is contained in the original extended abstract.

  9. The origin of the constellations

    NASA Astrophysics Data System (ADS)

    Roy, Archie E.

    The problem of the origin of the stellar constellations familiar to western astronomers from ancient times is discussed in an attempt to answer the classical detective story questions: Who? When? Why? and Where? The available astronomical, literary and archaeological evidence is examined to suggest a possible solution.

  10. Hybrid origin of Audubon's warbler.

    PubMed

    Brelsford, Alan; Milá, Borja; Irwin, Darren E

    2011-06-01

    Several animal species have recently been shown to have hybrid origins, but no avian examples have been documented with molecular evidence. We investigate whether the Audubon's warbler (Dendroica auduboni), one of four visually distinct species in the yellow-rumped warbler complex, has originated through hybridization between two other species in this group, the myrtle warbler (D. coronata) and black-fronted warbler (D. nigrifrons). Analysis of nuclear amplified fragment length polymorphism (AFLP) and sequence markers shows that Audubon's warblers are genetically intermediate and carry a mixture of alleles otherwise found only in one or the other of their putative parental species. Audubon's warblers also carry two deeply divergent mitochondrial DNA lineages, each shared with only one putative parental form. Broad clines between Audubon's and black-fronted warblers in AFLP markers call into question the validity of these two forms as full species; nevertheless, our results suggest that the Audubon's warbler probably originated through hybridization between two long-diverged species. It is likely that more cases of avian species of hybrid origin will be revealed by surveys of variation in nuclear DNA and other traits. PMID:21435063

  11. Climate Drives Polar Bear Origins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  12. Originism - Ethics and Extraterrestrial Life

    NASA Astrophysics Data System (ADS)

    Cockell, C. S.

    How should we treat extraterrestrial life, if we ever find it, and does a different origin of life imply a different ethical status? The most likely source of an ethical difference, or `originism,' is the inability to find a coherent definition of `life,' required to assess moral relevance in the first place. Although from a normative point of view biochemical architecture, in itself, does not provide a reason for a difference, there are numerous positions that might encourage us to treat an independent origin of life differently to life that is related to life on Earth. For example, from an instrumental point of view it would provide an opportunity to study another biological data point; it will be a new source of information about the evolution of life, and thus it might be afforded special status. We might consider extraterrestrial life to be special as prudence against the possibility of its mistreatment through an erroneous moral assessment of its worth. Whether extraterrestrial life exists of an independent origin or not, this analysis ultimately can provide a useful device for considering how we should treat entities on Earth whose status as `living' organisms is disputed, specifically viruses.

  13. Origin of the 'Extra Entropy'

    NASA Technical Reports Server (NTRS)

    Mushotzky, R.

    2008-01-01

    I will discuss how one can determine the origin of the 'extra entropy' in groups and clusters and the feedback needed in models of galaxy formation. I will stress the use of x-ray spectroscopy and imaging and the critical value that Con-X has in this regard.

  14. Increasing Originality in Written Expression.

    ERIC Educational Resources Information Center

    Belasco, Jack Thomas

    This study partially replicated Moss's "A Study of the Effect of Selected Methods of Instruction Designed to Increase Originality in Written Expression," except for the fact that this investigator taught a 5th grade and an 11th grade class for most of a school year. Some of the conclusions of the study were: no particular teaching technique was…

  15. The Chemistry of Life's Origin.

    ERIC Educational Resources Information Center

    Ferris, James P.

    1984-01-01

    From an understanding of how the solar system was formed, scientists have determined the conditions under which life probably originated on earth and, by experiment, have demonstrated a number of possible theories. These conditions, experiments, theories, and related topics are discussed. (JN)

  16. Historical Development of Origins Research

    PubMed Central

    Lazcano, Antonio

    2010-01-01

    Following the publication of the Origin of Species in 1859, many naturalists adopted the idea that living organisms were the historical outcome of gradual transformation of lifeless matter. These views soon merged with the developments of biochemistry and cell biology and led to proposals in which the origin of protoplasm was equated with the origin of life. The heterotrophic origin of life proposed by Oparin and Haldane in the 1920s was part of this tradition, which Oparin enriched by transforming the discussion of the emergence of the first cells into a workable multidisciplinary research program. On the other hand, the scientific trend toward understanding biological phenomena at the molecular level led authors like Troland, Muller, and others to propose that single molecules or viruses represented primordial living systems. The contrast between these opposing views on the origin of life represents not only contrasting views of the nature of life itself, but also major ideological discussions that reached a surprising intensity in the years following Stanley Miller’s seminal result which showed the ease with which organic compounds of biochemical significance could be synthesized under putative primitive conditions. In fact, during the years following the Miller experiment, attempts to understand the origin of life were strongly influenced by research on DNA replication and protein biosynthesis, and, in socio-political terms, by the atmosphere created by Cold War tensions. The catalytic versatility of RNA molecules clearly merits a critical reappraisal of Muller’s viewpoint. However, the discovery of ribozymes does not imply that autocatalytic nucleic acid molecules ready to be used as primordial genes were floating in the primitive oceans, or that the RNA world emerged completely assembled from simple precursors present in the prebiotic soup. The evidence supporting the presence of a wide range of organic molecules on the primitive Earth, including membrane

  17. Massive ascites of unknown origin

    PubMed Central

    Yuan, Shi-Min

    2014-01-01

    Massive ascites of unknown origin is an uncommon condition, which represent a diagnostic challenge. Patients with delayed diagnosis and treatment may have a poor prognosis. A 22-year-old female was referred to this hospital due to a 4-year progressive abdominal distension with massive ascites of unknown origin. By thorough investigations, she was eventually diagnosed as chronic calcified constrictive pericarditis. She received pericardiectomy and had an uneventful postoperative course. With a few day paracentesis, ascites did not progress any more. She was doing well at 5-month follow-up and has returned to work. Extracardiac manifestations, such as massive ascites and liver cirrhosis, were rare in patients with constrictive pericarditis. Pericardiectomy can be a radical solution for the treatment of chronic constrictive pericarditis. In order to avoid delayed diagnosis and treatment, physicians have to bear in mind this rare manifestation of chronic calcified constrictive pericarditis. PMID:24600502

  18. The origin of risk aversion

    PubMed Central

    Zhang, Ruixun; Brennan, Thomas J.; Lo, Andrew W.

    2014-01-01

    Risk aversion is one of the most basic assumptions of economic behavior, but few studies have addressed the question of where risk preferences come from and why they differ from one individual to the next. Here, we propose an evolutionary explanation for the origin of risk aversion. In the context of a simple binary-choice model, we show that risk aversion emerges by natural selection if reproductive risk is systematic (i.e., correlated across individuals in a given generation). In contrast, risk neutrality emerges if reproductive risk is idiosyncratic (i.e., uncorrelated across each given generation). More generally, our framework implies that the degree of risk aversion is determined by the stochastic nature of reproductive rates, and we show that different statistical properties lead to different utility functions. The simplicity and generality of our model suggest that these implications are primitive and cut across species, physiology, and genetic origins. PMID:25453072

  19. The Origin of the Elements

    SciTech Connect

    Murphy, Edward

    2012-11-20

    The world around us is made of atoms. Did you ever wonder where these atoms came from? How was the gold in our jewelry, the carbon in our bodies, and the iron in our cars made? In this lecture, we will trace the origin of a gold atom from the Big Bang to the present day, and beyond. You will learn how the elements were forged in the nuclear furnaces inside stars, and how, when they die, these massive stars spread the elements into space. You will learn about the origin of the building blocks of matter in the Big Bang, and we will speculate on the future of the atoms around us today.

  20. The Origin of the Elements

    ScienceCinema

    Murphy, Edward

    2014-08-06

    The world around us is made of atoms. Did you ever wonder where these atoms came from? How was the gold in our jewelry, the carbon in our bodies, and the iron in our cars made? In this lecture, we will trace the origin of a gold atom from the Big Bang to the present day, and beyond. You will learn how the elements were forged in the nuclear furnaces inside stars, and how, when they die, these massive stars spread the elements into space. You will learn about the origin of the building blocks of matter in the Big Bang, and we will speculate on the future of the atoms around us today.

  1. The diapsid origin of turtles.

    PubMed

    Schoch, Rainer R; Sues, Hans-Dieter

    2016-06-01

    The origin of turtles has been a persistent unresolved problem involving unsettled questions in embryology, morphology, and paleontology. New fossil taxa from the early Late Triassic of China (Odontochelys) and the Late Middle Triassic of Germany (Pappochelys) now add to the understanding of (i) the evolutionary origin of the turtle shell, (ii) the ancestral structural pattern of the turtle skull, and (iii) the phylogenetic position of Testudines. As has long been postulated on the basis of molecular data, turtles evolved from diapsid reptiles and are more closely related to extant diapsids than to parareptiles, which had been suggested as stem group by some paleontologists. The turtle cranium with its secondarily closed temporal region represents a derived rather than a primitive condition and the plastron partially evolved through the fusion of gastralia. PMID:26934902

  2. The Enigma of Angiosperm Origins

    NASA Astrophysics Data System (ADS)

    Hughes, Norman Francis

    2005-07-01

    The origins of angiosperms are still debated, despite many years of work by scientists from differing disciplines. The progress made toward resolving the problem is reviewed in this book. The author suggests that the only fruitful method of study is the total integrated use of the fossil record, particularly dispersed palynomorphs. This includes the use of electron microscopy and refined data handling to record the occurrence of microscopic fossils, rather than the extensive use of morphology and cladistics. The methods advocated in this book could result in a rethinking of the current classification of living plants, and it is hoped that the ideas presented will initiate discussion between both professionals and students of paleontology and plant science on the wider possibilities that may clarify the enigmatic origins of the dominant flowering plant groups.

  3. The Enigma of Angiosperm Origins

    NASA Astrophysics Data System (ADS)

    Hughes, Norman Francis

    1994-09-01

    The origins of angiosperms are still debated, despite many years of work by scientists from differing disciplines. The progress made toward resolving the problem is reviewed in this book. The author suggests that the only fruitful method of study is the total integrated use of the fossil record, particularly dispersed palynomorphs. This includes the use of electron microscopy and refined data handling to record the occurrence of microscopic fossils, rather than the extensive use of morphology and cladistics. The methods advocated in this book could result in a rethinking of the current classification of living plants, and it is hoped that the ideas presented will initiate discussion between both professionals and students of paleontology and plant science on the wider possibilities that may clarify the enigmatic origins of the dominant flowering plant groups.

  4. Origin of lunar light plains

    NASA Technical Reports Server (NTRS)

    Chao, E. C. T.; Hodges, C. A.; Boyce, J. M.; Soderblom, L. A.

    1975-01-01

    In order to determine the origin of Cayley-type lunar light plains, their physical properties, distribution, and relative ages are examined from Apollo orbital and Lunar Orbiter photographs. The distribution and apparent age of the plains deposits and data on highly feldspathic breccias indicate that these superficial materials are neither locally derived nor part of the Imbrium ejecta. The existence of a planar facies of continuous ejecta at Orientale and in the ejecta blankets of small craters is demonstrated. The data and interpretation presented support the hypothesis that the surface and near-surface materials of some light plains, including those at the Apollo 16 site, are at least partly composed of ejecta from the Orientale basin and that the materials of many rugged areas, such as the Descartes highlands, are overlain by similar material. The possibility that some Cayley-type plains may have a different origin is not excluded.

  5. Determination of plutonium metal origins

    SciTech Connect

    Moody, K.J.

    1995-02-01

    Forensic signatures are present in any Pu sample that can determine the sample`s origin: isotopic ratio of Pu, progeny species that grow into the sample, and contaminant species left over from incomplete purification of the Pu in fuel reprocessing. In the context of intelligence information, this can result in attribution of responsibility for the product of clandestine proliferant operations or material smuggled from existing stockpiles. A list of signature elements and what can be determined from them have been developed. Work needs to be done in converting concentrations of signature species into a quantitative forensic analysis, particularly in regard to reactor performance, but this should require only a small effort. A radiochemical analysis scheme has been developed for measuring these nuclides; more work is needed, particularly for determining fission product concentrations. A sample of Pu metal has been analyzed and several parameters determined that are strong indicators of its point of origin.

  6. The origin of risk aversion.

    PubMed

    Zhang, Ruixun; Brennan, Thomas J; Lo, Andrew W

    2014-12-16

    Risk aversion is one of the most basic assumptions of economic behavior, but few studies have addressed the question of where risk preferences come from and why they differ from one individual to the next. Here, we propose an evolutionary explanation for the origin of risk aversion. In the context of a simple binary-choice model, we show that risk aversion emerges by natural selection if reproductive risk is systematic (i.e., correlated across individuals in a given generation). In contrast, risk neutrality emerges if reproductive risk is idiosyncratic (i.e., uncorrelated across each given generation). More generally, our framework implies that the degree of risk aversion is determined by the stochastic nature of reproductive rates, and we show that different statistical properties lead to different utility functions. The simplicity and generality of our model suggest that these implications are primitive and cut across species, physiology, and genetic origins. PMID:25453072

  7. The origins of human ageing.

    PubMed Central

    Kirkwood, T B

    1997-01-01

    The origins of human ageing are to be found in the origins and evolution of senescence as a general feature in the life histories of higher animals. Ageing is an intriguing problem in evolutionary biology because a trait that limits the duration of life, including the fertile period, has a negative impact on Darwinian fitness. Current theory suggests that senescence occurs because the force of natural selection declines with age and because longevity is only acquired at some metabolic cost. In effect, organisms may trade late survival for enhanced reproductive investments in earlier life. The comparative study of ageing supports the general evolutionary theory and reveals that human senescence, while broadly similar to senescence in other mammalian species, has distinct features, such as menopause, that may derive from the interplay of biological and social evolution. PMID:9460059

  8. Dual origin of avian lymphatics.

    PubMed

    Wilting, Jörg; Aref, Yama; Huang, Ruijin; Tomarev, Stanislav I; Schweigerer, Lothar; Christ, Bodo; Valasek, Petr; Papoutsi, Maria

    2006-04-01

    The earliest signs of the lymphatic vascular system are the lymph sacs, which develop adjacent to specific embryonic veins. It has been suggested that sprouts from the lymph sacs form the complete lymphatic vascular system. We have studied the origin of the jugular lymph sacs (JLS), the dermal lymphatics and the lymph hearts of avian embryos. In day 6.5 embryos, the JLS is an endothelial-lined sinusoidal structure. The lymphatic endothelial cells (LECs) stain (in the quail) positive for QH1 antibody and soybean agglutinin. As early as day 4, the anlagen of the JLS can be recognized by their Prox1 expression. Prox1 is found in the jugular section of the cardinal veins, and in scattered cells located in the dermatomes along the cranio-caudal axis and in the splanchnopleura. In the quail, such cells are positive for Prox1 and QH1. In the jugular region, the veins co-express the angiopoietin receptor Tie2. Quail-chick-chimera studies show that the peripheral parts of the JLS form by integration of cells from the paraxial mesoderm. Intra-venous application of DiI-conjugated acetylated low-density lipoprotein into day 4 embryos suggests a venous origin of the deep parts of the JLS. Superficial lymphatics are directly derived from the dermatomes, as shown by dermatome grafting. The lymph hearts in the lumbo-sacral region develop from a plexus of Prox1-positive lymphatic capillaries. Both LECs and muscle cells of the lymph hearts are of somitic origin. In sum, avian lymphatics are of dual origin. The deep parts of the lymph sacs are derived from adjacent veins, the superficial parts of the JLS and the dermal lymphatics from local lymphangioblasts. PMID:16457798

  9. [Severe hemobilia of cholecystic origin].

    PubMed

    Miguil, M; Abassi, O; Margad, B; Harti, A; Benslama, A; Benaguida, M

    1991-02-01

    The authors report a case of severe hematobilia originating in the gall bladder itself ans associated with a cholecysto-colic fistula. They review the different etiologies of hematobilia and stress the major value of selective arteriography of the coeliac trunk and possible pitfalls in this condition. This case highlights the rare complications of cholelithiasis (hematobilia and cholecyto-colic fistula) and the severity of blood spoliation. Therapy is reviewed as a function of the lesion causing hematobilia. PMID:2026679

  10. Microbial origin of desert varnish.

    PubMed

    Dorn, R I; Oberlander, T M

    1981-09-11

    Scanning electron microscopy and energy dispersive x-ray analyses of desert varnish reveal that microorganisms concentrate ambient manganese that becomes greatly enhanced in brown to black varnish. Specific characteristics of desert varnish and of varnish bacteria support a microbial origin for manganese-rich films. Varnish microbes can be cultured and produce laboratory manganese films. Accordingly, natural desert varnish and also manganese-rich rock varnishes in nondesert environments appear to be a product of microbial activity. PMID:17744757

  11. The prenatal origins of cancer

    PubMed Central

    Marshall, Glenn M.; Carter, Daniel R.; Cheung, Belamy B.; Liu, Tao; Mateos, Marion K.; Meyerowitz, Justin G.; Weiss, William A.

    2014-01-01

    The concept that some childhood malignancies arise from postnatally persistent embryonal remnant or rest cells has a long history. Recent research has strengthened the links between driver mutations, and, embryonal and early postnatal development. This evidence, coupled with much greater detail on the cell of origin and the initial steps in embryonal cancer initiation, has identified important therapeutic targets and provided renewed interest in strategies for the early detection and prevention of childhood cancer. PMID:24599217

  12. Swine origin influenza (swine flu).

    PubMed

    Sebastian, Meghna R; Lodha, Rakesh; Kabra, S K

    2009-08-01

    Swine origin influenza was first recognized in the border area of Mexico and United States in April 2009 and during a short span of two months became the first pandemic. The currently circulating strain of swine origin influenza virus of the H1N1 strain has undergone triple reassortment and contains genes from the avian, swine and human viruses. It is transmitted by droplets or fomites. Incubation period is 2 to 7 days. Common clinical symptoms are indistinguishable by any viral respiratory illness, and include fever, cough, sore throat and myalgia. A feature seen more frequently with swine origin influenza is GI upset. Less than 10% of patients require hospitalization. Patients at risk of developing severe disease are - younger than five years, elderly, pregnant women, with chronic systemic illnesses, adolescents on aspirin. Of the severe manifestations of swine origin influenza, pneumonia and respiratory failure are the most common. Unusual symptoms reported are conjunctivitis, parotitis, hemophagocytic syndrome. Infants may present with fever and lethargy with no respiratory symptoms. Diagnosis is based on RT PCR, Viral culture or increasing neutralizing antibodies. Principle of treatment consist of isolation, universal precautions, good infection control practices, supportive care and use of antiviral drugs. Antiviral drugs effective against H1N1 virus include: oseltamivir and zamanavir. With good supportive care case fatality is less than 1%. Preventive measures include: social distancing, practicing respiratory etiquette, hand hygiene and use of chemoprohylaxis with antiviral drugs. Vaccine against H1N1 is not available at present, but will be available in near future. PMID:19802552

  13. Mechanisms and origin of multiferroicity

    NASA Astrophysics Data System (ADS)

    Barone, Paolo; Picozzi, Silvia

    2015-03-01

    Motivated by the potential applications of their intrinsic cross-coupling properties, the interest in multiferroic materials has constantly increased recently, leading to significant experimental and theoretical advances. From the theoretical point of view, recent progresses have allowed one to identify different mechanisms responsible for the appearance of ferroelectric polarization coexisting-and coupled-with magnetic properties. This chapter aims at reviewing the fundamental mechanisms devised so far, mainly in transition-metal oxides, which lie at the origin of multiferroicity.

  14. Fetal Origins of Adult Disease

    PubMed Central

    Calkins, Kara; Devaskar, Sherin U.

    2015-01-01

    Dr. David Barker first popularized the concept of fetal origins of adult disease (FOAD). Since its inception, FOAD has received considerable attention. The FOAD hypothesis holds that events during early development have a profound impact on one’s risk for development of future adult disease. Low birth weight, a surrogate marker of poor fetal growth and nutrition, is linked to coronary artery disease, hypertension, obesity, and insulin resistance. Clues originally arose from large 20th century, European birth registries. Today, large, diverse human cohorts and various animal models have extensively replicated these original observations. This review will focus on the pathogenesis related to FOAD and examines Dr. David Barker’s landmark studies, along with additional human and animal model data. Implications of the FOAD extend beyond the low birth weight population and include babies exposed to stress, both nutritional and non-nutritional, during different critical periods of development, which ultimately result in a disease state. By understanding FOAD, health care professionals and policy makers will make this issue a high healthcare priority and implement preventative measures and treatment for those at higher risk for chronic diseases. PMID:21684471

  15. Fetal origins of adult disease.

    PubMed

    Calkins, Kara; Devaskar, Sherin U

    2011-07-01

    Dr. David Barker first popularized the concept of fetal origins of adult disease (FOAD). Since its inception, FOAD has received considerable attention. The FOAD hypothesis holds that events during early development have a profound impact on one's risk for development of future adult disease. Low birth weight, a surrogate marker of poor fetal growth and nutrition, is linked to coronary artery disease, hypertension, obesity, and insulin resistance. Clues originally arose from large 20th century, European birth registries. Today, large, diverse human cohorts and various animal models have extensively replicated these original observations. This review focuses on the pathogenesis related to FOAD and examines Dr. David Barker's landmark studies, along with additional human and animal model data. Implications of the FOAD extend beyond the low birth weight population and include babies exposed to stress, both nutritional and nonnutritional, during different critical periods of development, which ultimately result in a disease state. By understanding FOAD, health care professionals and policy makers will make this issue a high health care priority and implement preventive measures and treatment for those at higher risk for chronic diseases. PMID:21684471

  16. The HORUS Origins Science Mission

    NASA Astrophysics Data System (ADS)

    Morse, J.; Scowen, P.; Beasley, M.; Woodruff, R.; HORUS MIssion Development

    2004-12-01

    The HORUS Origins Science Mission is a 2.4-meter class space observatory that will address key components in the NASA Origins Roadmap. HORUS will provide 100 times greater imaging efficiency than currently exists on HST and will restore UV spectroscopic capabilities with >10 times greater sensitivity than previous HST instruments. We present a synopsis of the requirements, technical implementation, and technology roadmap for this mission for conducting critical observations of the formation of planets, stars, and galaxies. The HORUS mission has a well-defined Origins scientific program at its heart: a systematic survey of local, intermediate, and high-redshift sites and indicators of star formation to investigate and understand the range of environments, feedback mechanisms, and other factors that most affect the outcome of the star and planet formation process and the path from the Big Bang to people. This program relies on focused capabilities unique to space and that no other planned NASA mission will provide: near-UV/visible (200-1100nm) wide-field, diffraction-limited imaging; and high-sensitivity, low- and medium-resolution UV (100-320nm) spectroscopy. This work is supported by NASA grant number NNG04GR33G to the Arizona State University.

  17. Changing ideas about eukaryotic origins

    PubMed Central

    Williams, Tom A.; Embley, T. Martin

    2015-01-01

    The origin of eukaryotic cells is one of the most fascinating challenges in biology, and has inspired decades of controversy and debate. Recent work has led to major upheavals in our understanding of eukaryotic origins and has catalysed new debates about the roles of endosymbiosis and gene flow across the tree of life. Improved methods of phylogenetic analysis support scenarios in which the host cell for the mitochondrial endosymbiont was a member of the Archaea, and new technologies for sampling the genomes of environmental prokaryotes have allowed investigators to home in on closer relatives of founding symbiotic partners. The inference and interpretation of phylogenetic trees from genomic data remains at the centre of many of these debates, and there is increasing recognition that trees built using inadequate methods can prove misleading, whether describing the relationship of eukaryotes to other cells or the root of the universal tree. New statistical approaches show promise for addressing these questions but they come with their own computational challenges. The papers in this theme issue discuss recent progress on the origin of eukaryotic cells and genomes, highlight some of the ongoing debates, and suggest possible routes to future progress. PMID:26323752

  18. [The origin of eukaryotic cells and origination of apoptosis].

    PubMed

    Galitskiĭ, V A

    2005-01-01

    The unified conception of the origin of eukaryotic cells has been proposed. In the author's opinion, evolutionary transformation of prokaryotic cell into eukaryotic cell took place 3.3-1.4 billion years ago and involved the next four stages: 1) the appearance of intracellular membranes due to prokaryotic cell plasmalemma invaginating into its cytoplasm; 2) the cell nucleus formation by the double sheet of intracellular membrane surrounding and sequestrating genetic material of the cell; 3) the appearance of cytoskeleton in parallel with mitotic spindle formation and gradual transition from prokaryotic way of cell division to mitosis; 4) the establishment of symbiosis between the evolving nucleated cell and prokaryotic microorganicsms that subsequently transform into mitochondria and chloroplasts. Apoptosis of cells of the present day multicellular eukaryotic organisms is supposed to be an evolutionary altered response of mitochondrian predecessors to the influence of factors, which are able to damage eukaryotic host cell. The initial biological significance of this reaction pertained to attempts of endosymbionts to leave the host cell as soon as possible, if the probability of its irreversible injury was very high, and by this to escape from their death. It is possible that numerous proteins, known as sensors or transducers of proapoptotic signals in Bcl-2--p53-dependent apoptotic pathway, were initially encoded by mitochondrial genome, whereas antiapoptotic factors and also components of receptor-mediated and granzyme B perforin dependent apoptotic pathways have cellular origin. PMID:16706173

  19. 7 CFR 201.14 - Origin.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Labeling Agricultural Seeds § 201.14 Origin. (a) Alfalfa, red clover, white clover, and field corn (except hybrid seed corn) shall be labeled to show: (1) The origin, if known; or (2) if the origin is not known... 7 Agriculture 3 2012-01-01 2012-01-01 false Origin. 201.14 Section 201.14 Agriculture...

  20. Musical emotions: functions, origins, evolution.

    PubMed

    Perlovsky, Leonid

    2010-03-01

    Theories of music origins and the role of musical emotions in the mind are reviewed. Most existing theories contradict each other, and cannot explain mechanisms or roles of musical emotions in workings of the mind, nor evolutionary reasons for music origins. Music seems to be an enigma. Nevertheless, a synthesis of cognitive science and mathematical models of the mind has been proposed describing a fundamental role of music in the functioning and evolution of the mind, consciousness, and cultures. The review considers ancient theories of music as well as contemporary theories advanced by leading authors in this field. It addresses one hypothesis that promises to unify the field and proposes a theory of musical origin based on a fundamental role of music in cognition and evolution of consciousness and culture. We consider a split in the vocalizations of proto-humans into two types: one less emotional and more concretely-semantic, evolving into language, and the other preserving emotional connections along with semantic ambiguity, evolving into music. The proposed hypothesis departs from other theories in considering specific mechanisms of the mind-brain, which required the evolution of music parallel with the evolution of cultures and languages. Arguments are reviewed that the evolution of language toward becoming the semantically powerful tool of today required emancipation from emotional encumbrances. The opposite, no less powerful mechanisms required a compensatory evolution of music toward more differentiated and refined emotionality. The need for refined music in the process of cultural evolution is grounded in fundamental mechanisms of the mind. This is why today's human mind and cultures cannot exist without today's music. The reviewed hypothesis gives a basis for future analysis of why different evolutionary paths of languages were paralleled by different evolutionary paths of music. Approaches toward experimental verification of this hypothesis in

  1. On the Origin of Monsoon

    NASA Technical Reports Server (NTRS)

    Chao, Winston C.; Chen, Baode; Einaudi, Franco (Technical Monitor)

    2000-01-01

    It is a long-held fundamental belief that the basic cause of a monsoon is land-sea thermal contrast on the continental scale. Through general circulation model experiments we demonstrate that this belief should be changed. The Asian and Australian summer monsoon circulations are largely intact in an experiment in which Asia, maritime continent, and Australia are replaced by ocean. It is also shown that the change resulting from such replacement is in general due more to the removal of topography than to the removal of land-sea contrast. Therefore, land-sea contrast plays only a minor modifying role in Asian and Australian summer monsoons. This also happens to the Central American summer monsoon. However, the same thing cannot be said of the African and South American summer monsoons. In Asian and Australian winter monsoons land-sea contrast also plays only a minor role. Our interpretation for the origin of monsoon is that the summer monsoon is the result of ITCZ's (intertropical convergence zones) peak being substantially (more than 10 degrees) away from the equator. The origin of the ITCZ has been previously interpreted by Chao. The circulation around thus located ITCZ, previously interpreted by Chao and Chen through the modified Gill solution and briefly described in this paper, explains the monsoon circulation. The longitudinal location of the ITCZs is determined by the distribution of surface conditions. ITCZ's favor locations of higher SST as in western Pacific and Indian Ocean, or tropical landmass, due to land-sea contrast, as in tropical Africa and South America. Thus, the role of landmass in the origin of monsoon can be replaced by ocean of sufficiently high SST. Furthermore, the ITCZ circulation extends into the tropics in the other hemisphere to give rise to the winter monsoon circulation there. Also through the equivalence of land-sea contrast and higher SST, it is argued that the basic monsoon onset mechanism proposed by Chao is valid for all monsoons.

  2. Musical emotions: Functions, origins, evolution

    NASA Astrophysics Data System (ADS)

    Perlovsky, Leonid

    2010-03-01

    Theories of music origins and the role of musical emotions in the mind are reviewed. Most existing theories contradict each other, and cannot explain mechanisms or roles of musical emotions in workings of the mind, nor evolutionary reasons for music origins. Music seems to be an enigma. Nevertheless, a synthesis of cognitive science and mathematical models of the mind has been proposed describing a fundamental role of music in the functioning and evolution of the mind, consciousness, and cultures. The review considers ancient theories of music as well as contemporary theories advanced by leading authors in this field. It addresses one hypothesis that promises to unify the field and proposes a theory of musical origin based on a fundamental role of music in cognition and evolution of consciousness and culture. We consider a split in the vocalizations of proto-humans into two types: one less emotional and more concretely-semantic, evolving into language, and the other preserving emotional connections along with semantic ambiguity, evolving into music. The proposed hypothesis departs from other theories in considering specific mechanisms of the mind-brain, which required the evolution of music parallel with the evolution of cultures and languages. Arguments are reviewed that the evolution of language toward becoming the semantically powerful tool of today required emancipation from emotional encumbrances. The opposite, no less powerful mechanisms required a compensatory evolution of music toward more differentiated and refined emotionality. The need for refined music in the process of cultural evolution is grounded in fundamental mechanisms of the mind. This is why today's human mind and cultures cannot exist without today's music. The reviewed hypothesis gives a basis for future analysis of why different evolutionary paths of languages were paralleled by different evolutionary paths of music. Approaches toward experimental verification of this hypothesis in

  3. Planetary Origin Evolution and Structure

    NASA Technical Reports Server (NTRS)

    Stevenson, David J.

    2005-01-01

    This wide-ranging grant supported theoretical modeling on many aspects of the formation, evolution and structure of planets and satellites. Many topics were studied during this grant period, including the evolution of icy bodies; the origin of magnetic fields in Ganymede; the thermal histories of terrestrial planets; the nature of flow inside giant planets (especially the coupling to the magnetic field) and the dynamics of silicate/iron mixing during giant impacts and terrestrial planet core formation. Many of these activities are ongoing and have not reached completion. This is the nature of this kind of research.

  4. The origin of membrane bioenergetics.

    PubMed

    Lane, Nick; Martin, William F

    2012-12-21

    Harnessing energy as ion gradients across membranes is as universal as the genetic code. We leverage new insights into anaerobe metabolism to propose geochemical origins that account for the ubiquity of chemiosmotic coupling, and Na(+)/H(+) transporters in particular. Natural proton gradients acting across thin FeS walls within alkaline hydrothermal vents could drive carbon assimilation, leading to the emergence of protocells within vent pores. Protocell membranes that were initially leaky would eventually become less permeable, forcing cells dependent on natural H(+) gradients to pump Na(+) ions. Our hypothesis accounts for the Na(+)/H(+) promiscuity of bioenergetic proteins, as well as the deep divergence between bacteria and archaea. PMID:23260134

  5. Olmec origins of Mesoamerican writing.

    PubMed

    Pohl, Mary E D; Pope, Kevin O; von Nagy, Christopher

    2002-12-01

    A cylinder seal and carved greenstone plaque bearing glyphs dating to approximately 650 B.C. have been uncovered near the Olmec center of La Venta in Tabasco, Mexico. These artifacts, which predate others containing writing, reveal that the key aspects of the Mesoamerican scripts were present in Olmec writing: the combination of pictographic and glyphic elements to represent speech; the use of the sacred 260-day calendar; and the connection between writing, the calendar, and kingship. They imply that Mesoamerican writing originated in the La Venta polity. PMID:12471256

  6. "Magic melters" have geometrical origin.

    PubMed

    Joshi, Kavita; Krishnamurty, Sailaja; Kanhere, D G

    2006-04-01

    Recent experimental reports bring out extreme size sensitivity in the heat capacities of gallium and aluminum clusters. In the present work we report results of our extensive ab initio molecular dynamical simulations on Ga30 and Ga31, the pair which has shown rather dramatic size sensitivity. We trace the origin of this size sensitive heat capacities to the relative order in their respective ground state geometries. Such an effect of nature of the ground state on the characteristics of heat capacity is also seen in case of small gallium and sodium clusters, indicating that the observed size sensitivity is a generic feature of small clusters. PMID:16712002

  7. ``Magic Melters'' Have Geometrical Origin

    NASA Astrophysics Data System (ADS)

    Joshi, Kavita; Krishnamurty, Sailaja; Kanhere, D. G.

    2006-04-01

    Recent experimental reports bring out extreme size sensitivity in the heat capacities of gallium and aluminum clusters. In the present work we report results of our extensive ab initio molecular dynamical simulations on Ga30 and Ga31, the pair which has shown rather dramatic size sensitivity. We trace the origin of this size sensitive heat capacities to the relative order in their respective ground state geometries. Such an effect of nature of the ground state on the characteristics of heat capacity is also seen in case of small gallium and sodium clusters, indicating that the observed size sensitivity is a generic feature of small clusters.

  8. Origin and History of Magnolias

    NASA Astrophysics Data System (ADS)

    Hebda, R. J.; Irving, E.

    2004-12-01

    The classic disjunct distribution of living magnolias between southeast Asia and the Americas has been a puzzle for more than a century and a half. We propose a scheme for the origin and history of magnolias to explain this distribution by integrating paleogeographic, paleoclimatic, paleobotanical, and phytogeographic data. Our scheme is based on paleomagnetically determined latitudes. We assume that the moist warm temperate climate favoured by most extant magnolias has always been their preference. Molecular analyses (largely chloroplast DNA) reveal that several North American species are distinct and basal forms suggesting that magnolias likely originated in North America, a conclusion supported by the fossil record. We identify four evolutionary stages: (1) Ancestral magnolias originate in the Late Cretaceous of North America in high mid-latitudes (45° -60° N) at low altitudes under greenhouse climates. (2) During the exceptionally warm climate (super-greenhouse) of the Eocene, magnolias spread eastwards via the Iceland-Faroes isthmuses, to Europe and then across west and central Asia possibly to east Asia, still at low altitudes and high mid-latitudes. (3) With global cooling from the mid-Cenozoic, magnolias shift their core range to lower mid-latitudes (30° -45° N), become extinct in Europe and southern Siberia, breaking the once continuous distribution into two. (4) In the late Cenozoic, as ice-house conditions develop, magnolias diversify rapidly and expand southward into moist warm temperate uplands in newly uplifted mountain ranges of South and Central America, southeast Asia and the High Archipelago between southeast Asia and Australia. The late Cenozoic evolution of magnolias is characterized by the impoverishment of northerly species and diversification of southerly species. Thus, the centre of origin is not the center of diversity today. Disjunction at the generic level likely occurred as part of the mid-Tertiary southward displacement of the

  9. On the origin of leprosy.

    PubMed

    Monot, Marc; Honoré, Nadine; Garnier, Thierry; Araoz, Romulo; Coppée, Jean-Yves; Lacroix, Céline; Sow, Samba; Spencer, John S; Truman, Richard W; Williams, Diana L; Gelber, Robert; Virmond, Marcos; Flageul, Béatrice; Cho, Sang-Nae; Ji, Baohong; Paniz-Mondolfi, Alberto; Convit, Jacinto; Young, Saroj; Fine, Paul E; Rasolofo, Voahangy; Brennan, Patrick J; Cole, Stewart T

    2005-05-13

    Leprosy, a chronic human disease with potentially debilitating neurological consequences, results from infection with Mycobacterium leprae. This unculturable pathogen has undergone extensive reductive evolution, with half of its genome now occupied by pseudogenes. Using comparative genomics, we demonstrated that all extant cases of leprosy are attributable to a single clone whose dissemination worldwide can be retraced from analysis of very rare single-nucleotide polymorphisms. The disease seems to have originated in Eastern Africa or the Near East and spread with successive human migrations. Europeans or North Africans introduced leprosy into West Africa and the Americas within the past 500 years. PMID:15894530

  10. Origins of the "Western" Constellations

    NASA Astrophysics Data System (ADS)

    Frank, Roslyn M.

    The development of the 48 Greek constellations is analyzed as a complex mixture of cognitive layers deriving from different cultural traditions and dating back to different epochs. The analysis begins with a discussion of the zodiacal constellations, goes on to discuss the stellar lore in Homer and Hesiod, and then examines several theories concerning the origins of the southern non-zodiacal constellations. It concludes with a commentary concerning the age and possible cultural significance of stars of the Great Bear constellation in light of ethnohistorical documentation, folklore, and beliefs related to European bear ceremonialism.

  11. New perspectives on anthropoid origins

    PubMed Central

    Williams, Blythe A.; Kay, Richard F.; Kirk, E. Christopher

    2010-01-01

    Adaptive shifts associated with human origins are brought to light as we examine the human fossil record and study our own genome and that of our closest ape relatives. However, the more ancient roots of many human characteristics are revealed through the study of a broader array of living anthropoids and the increasingly dense fossil record of the earliest anthropoid radiations. Genomic data and fossils of early primates in Asia and Africa clarify relationships among the major clades of primates. Progress in comparative anatomy, genomics, and molecular biology point to key changes in sensory ecology and brain organization that ultimately set the stage for the emergence of the human lineage. PMID:20212104

  12. Activation of a dormant replication origin is essential for Haloferax mediterranei lacking the primary origins

    PubMed Central

    Yang, Haibo; Wu, Zhenfang; Liu, Jingfang; Liu, Xiaoqing; Wang, Lei; Cai, Shuangfeng; Xiang, Hua

    2015-01-01

    The use of multiple origins for chromosome replication has been demonstrated in archaea. Similar to the dormant origins in eukaryotes, some potential origins in archaea appear to be inactive during genome replication. We have comprehensively explored the origin utilization in Haloferax mediterranei. Here we report three active chromosomal origins by genome-wide replication profiling, and demonstrate that when these three origins are deleted, a dormant origin becomes activated. Notably, this dormant origin cannot be further deleted when the other origins are already absent and vice versa. Interestingly, a potential origin that appears to stay dormant in its native host H. volcanii lacking the main active origins becomes activated and competent for replication of the entire chromosome when integrated into the chromosome of origin-deleted H. mediterranei. These results indicate that origin-dependent replication is strictly required for H. mediterranei and that dormant replication origins in archaea can be activated if needed. PMID:26374389

  13. Origin of marine planktonic cyanobacteria

    PubMed Central

    Sánchez-Baracaldo, Patricia

    2015-01-01

    Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600–2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500–542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600–1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000–542 Mya). PMID:26621203

  14. The Origin of Cosmic Rays

    ScienceCinema

    Blasi, Pasquale [INAF/Arcetri-Italy and Fermilab, Italy

    2010-01-08

    Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the ?end? of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform ?cosmic ray astronomy?, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

  15. Origins of Giant Molecular Clouds

    NASA Astrophysics Data System (ADS)

    Ostriker, E. C.; Kim, W.-T.

    2004-12-01

    The material in giant molecular clouds (GMCs) constitutes a large proportion of the Milky Way's ISM, and determining how cloud-formation processes affect the properties and spatial distribution of GMCs is important to understanding the structure of the Milky Way. Understanding the formation of GMCs is also key to theories of galactic evolution because it represents the first stage in the overall process of star formation. Several lines of evidence point to a need for relatively rapid GMC formation via coherent dynamical instabilities, and both Parker- and Jeans- type modes have been proposed as potential cloud-forming mechanisms. Recent numerical simulations have investigated these instabilities directly, using spatially-localized models of the interstellar medium that self-consistently incorporate rotational shear, self-gravity, and magnetic fields, as well as the effects of stellar spiral arms. These models have demonstrated that condensation via gravitational instability, aided by magnetic torques, is the most likely candidate for explaining the formation of GMCs. The models have also shown that spiral arm ``spurs'' -- clearly seen as regular projections from dust lanes in at least one external galaxy -- may originate as magneto-gravitational instabilities of the ISM within the dense portions of stellar spiral arms. This raises the interesting possibility that spur structures with similar dynamical origins could potentially be present in the Milky Way as well.

  16. Ancient voyaging and Polynesian origins.

    PubMed

    Soares, Pedro; Rito, Teresa; Trejaut, Jean; Mormina, Maru; Hill, Catherine; Tinkler-Hundal, Emma; Braid, Michelle; Clarke, Douglas J; Loo, Jun-Hun; Thomson, Noel; Denham, Tim; Donohue, Mark; Macaulay, Vincent; Lin, Marie; Oppenheimer, Stephen; Richards, Martin B

    2011-02-11

    The "Polynesian motif" defines a lineage of human mtDNA that is restricted to Austronesian-speaking populations and is almost fixed in Polynesians. It is widely thought to support a rapid dispersal of maternal lineages from Taiwan ~4000 years ago (4 ka), but the chronological resolution of existing control-region data is poor, and an East Indonesian origin has also been proposed. By analyzing 157 complete mtDNA genomes, we show that the motif itself most likely originated >6 ka in the vicinity of the Bismarck Archipelago, and its immediate ancestor is >8 ka old and virtually restricted to Near Oceania. This indicates that Polynesian maternal lineages from Island Southeast Asia gained a foothold in Near Oceania much earlier than dispersal from either Taiwan or Indonesia 3-4 ka would predict. However, we find evidence in minor lineages for more recent two-way maternal gene flow between Island Southeast Asia and Near Oceania, likely reflecting movements along a "voyaging corridor" between them, as previously proposed on archaeological grounds. Small-scale mid-Holocene movements from Island Southeast Asia likely transmitted Austronesian languages to the long-established Southeast Asian colonies in the Bismarcks carrying the Polynesian motif, perhaps also providing the impetus for the expansion into Polynesia. PMID:21295281

  17. Entropic origin of allometry relations

    NASA Astrophysics Data System (ADS)

    West, Bruce J.; West, Damien

    2015-03-01

    The theoretical allometry relation (AR) between the size of a network Y and a property of the network X is of the form X = aYb and has been known for nearly two centuries. The allometry coefficient a and allometry exponent b have been fit by various data sets over that time. The ubiquity of ARs in biology, sociology, ecology and indeed in virtually all the other science disciplines entreats science to find the origin of ARs. Data analysis indicates that the empirical AR is obtained with the replacements X → and Y → and the brackets denote an average over an ensemble of realizations of the network. It has been shown that the empirical AR cannot usually be derived from the theoretical one by simple averaging due to the fractal statistics of the fluctuations. Consequently we hypothesize that a possible origin of AR is the Principle of Minimum Entropy Generation (PMEG). We establish in support of this hypothesis that if the fluctuations in the allometry variables have fractal statistics then the PMEG entails the AR between a complex host network and a subnetwork strongly coupled to it.

  18. The origin of light hydrocarbons

    SciTech Connect

    Mango, F.D.

    2000-04-01

    The light hydrocarbons (LHs) are probably intermediates in the catalytic decomposition of oil to gas. Two lines of evidence support this possibility. First, the reaction was duplicated experimentally under moderate conditions. Second, natural LHs exhibit the characteristics of catalytic products, in particular a proportionality between isomers: (xy{sub i})/(x{sub i}y) = {alpha} (where x and x{sub i} are isomers; y and y{sub i} are isomers that are structurally similar to x and x{sub i}; and {alpha} is a constant). All oils exhibit this relationship with coefficients of correlation reaching 0.99. Isomer ratios change systematically with concentrations, some approaching thermodynamic equilibrium, others not. The correlations reported are the strongest yet disclosed for the LHs. Isomers are related in triads (e.g., n-hexane {leftrightarrow} 2-methylpentane {leftrightarrow} 3-methylpentane), consistent with cyclopropane precursors. The LHs obtained experimentally are indistinguishable from natural LHs in (xy{sub i})/(x{sub i}y). These relationships are not explained by physical fractionations, equilibrium control, or noncatalytic modes of origin. A catalytic origin, on the other hand, has precedence, economy and experimental support.

  19. Langerhans cell origin and regulation

    PubMed Central

    Collin, Matthew; Milne, Paul

    2015-01-01

    Purpose To summarize recent research on the ontogeny of Langerhans cells and regulation of their homeostasis in quiescent and inflamed conditions Recent findings Langerhans cells (LCs) originate pre-natally and may endure throughout life, independently of bone marrow derived precursors. Fate mapping experiments have recently resolved the relative contribution of primitive yolk sac and fetal liver hematopoiesis to the initial formation of LCs. In post-natal life, local self-renewal restores LC numbers following chronic or low grade inflammatory insults. However, severe inflammation recruits de novo bone marrow derived precursors in two waves; a transient population of classical monocytes followed by uncharacterized myeloid precursors that form a stable self-renewing LC network as inflammation subsides. Human CD1c+ dendritic cells have LC potential in vitro, raising the possibility that DC progenitors provide the second wave. LC development depends upon TGFβ receptor signaling with distinct pathways active during differentiation and homeostasis. LC survival is mediated by multiple pathways including mTOR and ERK signaling, mechanisms that become highly relevant in LC neoplasia. Summary The study of LCs continues to provide novel and unexpected insights into the origin and regulation of myeloid cell populations. The melding of macrophage and DC biology, shaped by a unique habitat, is a special feature of LCs. PMID:26554892

  20. Origin of marine planktonic cyanobacteria.

    PubMed

    Sánchez-Baracaldo, Patricia

    2015-01-01

    Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600-2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500-542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600-1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000-542 Mya). PMID:26621203

  1. The origins of modern divorce.

    PubMed

    Coontz, Stephanie

    2007-03-01

    High rates of marital dissolution and easy access to divorce are not unprecedented, historically or cross-culturally. But contemporary divorce in North America and Western Europe has different origins and features than divorce in previous cultures. The origins of modern divorce patterns date back more than 200 years, to the invention of the historically unprecedented idea that marriage should be based on love and mutual affection. Ironically, then, the fragility of modern marriage stems from the same values that have elevated the marital relationship above all other personal and familial commitments: the concentration of emotion, passion, personal identity, and self-validation in the couple relationship and the attenuation of emotional attachments and obligations beyond the conjugal unit. The immediate causes of divorce may range from factors as diverse as the personal psychological characteristics of one or both spouses to the stresses of economic hardship and community disintegration. But in a larger perspective, the role of divorce in modern societies and its relatively high occurrence both flow from the same complex of factors that have made good marriages so much more central to people's happiness than through most of the past, and deterioration of a marital relationship so much more traumatic. PMID:17375725

  2. Origins of narcissism in children

    PubMed Central

    Brummelman, Eddie; Thomaes, Sander; Nelemans, Stefanie A.; Orobio de Castro, Bram; Overbeek, Geertjan; Bushman, Brad J.

    2015-01-01

    Narcissism levels have been increasing among Western youth, and contribute to societal problems such as aggression and violence. The origins of narcissism, however, are not well understood. Here, we report, to our knowledge, the first prospective longitudinal evidence on the origins of narcissism in children. We compared two perspectives: social learning theory (positing that narcissism is cultivated by parental overvaluation) and psychoanalytic theory (positing that narcissism is cultivated by lack of parental warmth). We timed the study in late childhood (ages 7–12), when individual differences in narcissism first emerge. In four 6-mo waves, 565 children and their parents reported child narcissism, child self-esteem, parental overvaluation, and parental warmth. Four-wave cross-lagged panel models were conducted. Results support social learning theory and contradict psychoanalytic theory: Narcissism was predicted by parental overvaluation, not by lack of parental warmth. Thus, children seem to acquire narcissism, in part, by internalizing parents’ inflated views of them (e.g., “I am superior to others” and “I am entitled to privileges”). Attesting to the specificity of this finding, self-esteem was predicted by parental warmth, not by parental overvaluation. These findings uncover early socialization experiences that cultivate narcissism, and may inform interventions to curtail narcissistic development at an early age. PMID:25775577

  3. Origins of narcissism in children.

    PubMed

    Brummelman, Eddie; Thomaes, Sander; Nelemans, Stefanie A; Orobio de Castro, Bram; Overbeek, Geertjan; Bushman, Brad J

    2015-03-24

    Narcissism levels have been increasing among Western youth, and contribute to societal problems such as aggression and violence. The origins of narcissism, however, are not well understood. Here, we report, to our knowledge, the first prospective longitudinal evidence on the origins of narcissism in children. We compared two perspectives: social learning theory (positing that narcissism is cultivated by parental overvaluation) and psychoanalytic theory (positing that narcissism is cultivated by lack of parental warmth). We timed the study in late childhood (ages 7-12), when individual differences in narcissism first emerge. In four 6-mo waves, 565 children and their parents reported child narcissism, child self-esteem, parental overvaluation, and parental warmth. Four-wave cross-lagged panel models were conducted. Results support social learning theory and contradict psychoanalytic theory: Narcissism was predicted by parental overvaluation, not by lack of parental warmth. Thus, children seem to acquire narcissism, in part, by internalizing parents' inflated views of them (e.g., "I am superior to others" and "I am entitled to privileges"). Attesting to the specificity of this finding, self-esteem was predicted by parental warmth, not by parental overvaluation. These findings uncover early socialization experiences that cultivate narcissism, and may inform interventions to curtail narcissistic development at an early age. PMID:25775577

  4. On the Origin of Heterotrophy.

    PubMed

    Schönheit, Peter; Buckel, Wolfgang; Martin, William F

    2016-01-01

    The theory of autotrophic origins of life posits that the first cells on Earth satisfied their carbon needs from CO2. At hydrothermal vents, spontaneous synthesis of methane via serpentinization links an energy metabolic reaction with a geochemical homologue. If the first cells were autotrophs, how did the first heterotrophs arise, and what was their substrate? We propose that cell mass roughly similar to the composition of Escherichia coli was the substrate for the first chemoorganoheterotrophs. Amino acid fermentations, pathways typical of anaerobic clostridia and common among anaerobic archaea, in addition to clostridial type purine fermentations, might have been the first forms of heterotrophic carbon and energy metabolism. Ribose was probably the first abundant sugar, and the archaeal type III RubisCO pathway of nucleoside monophosphate conversion to 3-phosphoglycerate might be a relic of ancient heterotrophy. Participation of chemiosmotic coupling and flavin-based electron bifurcation--a soluble energy coupling process--in clostridial amino acid and purine fermentations is consistent with an autotrophic origin of both metabolism and heterotrophy, as is the involvement of S(0) as an electron acceptor in the facilitated fermentations of anaerobic heterotrophic archaea. PMID:26578093

  5. On the origin of life.

    PubMed

    Szostak, Jack W

    2016-01-01

    The origin of life is a very rich field, filled with possibilities and ripe for discovery. RNA replication requires chemical energy and vesicle division is easy to do with mechanical energy. These requirements point to a surface lake, perhaps at some time following the period of concentrated cyanide chemistry that gave rise to nucleotides, amino acids and (maybe) fatty acids. A second requirement follows specifically from the nature of the RNA replication cycle, which requires generally cool to moderate temperatures for the copying chemistry, punctuated by brief periods of high temperature for strand separation. Remarkably, lakes in a geothermal active area provide just such a fluctuating temperature environment, because lakes similar to Yellowstone can be generally cool (even ice covered in winter), but they contain numerous hydrothermal vents that emit streams of hot water. Protocells in such an environment would occasionally be swept into these hot water streams, where the transient high temperature exposure would cause RNA strand separation. However, the protocells would be quickly mixed with surrounding cold water, and would therefore cool quickly, before their delicate RNA molecules could be destroyed by heat. Because of the combination of favorable chemical and physical environments, this could be the most likely scenario for the early Earth environment that nurtured the origin of life. PMID:27576276

  6. Ancient origin of mast cells.

    PubMed

    Wong, G William; Zhuo, Lisheng; Kimata, Koji; Lam, Bing K; Satoh, Nori; Stevens, Richard L

    2014-08-22

    The sentinel roles of mammalian mast cells (MCs) in varied infections raised the question of their evolutionary origin. We discovered that the test cells in the sea squirt Ciona intestinalis morphologically and histochemically resembled cutaneous human MCs. Like the latter, C. intestinalis test cells stored histamine and varied heparin·serine protease complexes in their granules. Moreover, they exocytosed these preformed mediators when exposed to compound 48/80. In support of the histamine data, a C. intestinalis-derived cDNA was isolated that resembled that which encodes histidine decarboxylase in human MCs. Like heparin-expressing mammalian MCs, activated test cells produced prostaglandin D2 and contained cDNAs that encode a protein that resembles the synthase needed for its biosynthesis in human MCs. The accumulated morphological, histochemical, biochemical, and molecular biology data suggest that the test cells in C. intestinalis are the counterparts of mammalian MCs that reside in varied connective tissues. The accumulated data point to an ancient origin of MCs that predates the emergence of the chordates >500million years ago, well before the development of adaptive immunity. The remarkable conservation of MCs throughout evolution is consistent with their importance in innate immunity. PMID:25094046

  7. Geochemical Origin of Biological Molecules

    NASA Astrophysics Data System (ADS)

    Bassez, Marie-Paule

    2013-04-01

    A model for the geochemical origin of biological molecules is presented. Rocks such as peridotites and basalts, which contain ferromagnesian minerals, evolve in the presence of water. Their hydrolysis is an exothermic reaction which generates heat and a release of H2 and of minerals with modified structures. The hydrogen reacts with the CO2 embedded inside the rock or with the CO2 of the environment to form CO in an hydrothermal process. With the N2 of the environment, and with an activation source arising from cosmic radiation, ferromagnesian rocks might evolve towards the abiotic formation of biological molecules, such as peptide like macromolecules which produce amino acids after acid hydrolysis. The reactions concerned are described. The production of hydrothermal CO is discussed in geological sites containing ferromagnesian silicate minerals and the low intensity of the Earth's magnetic field during Paleoarchaean Era is also discussed. It is concluded that excitation sources arising from cosmic radiation were much more abundant during Paleoarchaean Era and that macromolecular structures of biological relevance might consequently form during Archaean Eon, as a product of the chemical evolution of the rocks and of their mineral contents. This synthesis of abiotically formed biological molecules is consecutively discussed for meteorites and other planets such as Mars. This model for the geochemical origin of biological molecules has first been proposed in 2008 in the context of reactions involving catalysers such as kaolinite [Bassez 2008a] and then presented in conferences and articles [Bassez 2008b, 2009, 2012; Bassez et al. 2009a to 2012b]. BASSEZ M.P. 2008a Synthèse prébiotique dans les conditions hydrothermales, CNRIUT'08, Lyon 29-30/05/2008, Conf. and open access article:http://liris.cnrs.fr/~cnriut08/actes/ 29 mai 11h-12h40. BASSEZ M.P. 2008b Prebiotic synthesis under hydrothermal conditions, ISSOL'08, P2-6, Firenze-Italy, 24-29/08/2008. Poster at the

  8. Origins and Evolution of Life

    NASA Astrophysics Data System (ADS)

    Gargaud, Muriel; López-García, Purificación; Martin, Hervé

    2011-01-01

    Part I. What Is Life?: 1. Problems raised by a definition of life M. Morange; 2. Some remarks about uses of cosmological anthropic 'principles' D. Lambert; 3. Minimal cell: the biologist point of view C. Brochier-Armanet; 4. Minimal cell: the computer scientist point of view H. Bersini; 5. Origins of life: computing and simulation approaches B. Billoud; Part II. Astronomical and Geophysical Context of the Emergence of Life: 6. Organic molecules in interstellar medium C. Ceccarelli and C. Cernicharo; 7. Cosmochemical evolution and the origin of life: insights from meteorites S. Pizzarello; 8. Astronomical constraints on the emergence of life M. Gounelle and T. Montmerle; 9. Formation of habitable planets J. Chambers; 10. The concept of galactic habitable zone N. Prantzos; 11. The young Sun and its influence on planetary atmospheres M. Güdel and J. Kasting; 12. Climates of the Earth G. Ramstein; Part III. Role of Water in the Emergence of Life: 13. Liquid water: a necessary condition to all forms of life K. Bartik, G. Bruylants, E. Locci and J. Reisse; 14. The role of water in the formation and evolution of planets T. Encrenaz; 15. Water on Mars J. P. Bibring; Part IV. From Non-Living Systems to Life: 16. Energetic constraints on prebiotic pathways: application to the emergence of translation R. Pascal and L. Boiteau; 17. Comparative genomics and early cell evolution A. Lazcano; 18. Origin and evolution of metabolisms J. Peretó; Part V. Mechanisms for Life Evolution: 19. Molecular phylogeny: inferring the patterns of evolution E. Douzery; 20. Horizontal gene transfer: mechanisms and evolutionary consequences D. Moreira; 21. The role of symbiosis in eukaryotic evolution A. Latorre, A. Durbán, A. Moya and J. Peretó; Part VI. Life in Extreme Conditions: 22. Life in extreme conditions: Deinococcus radiodurans, an organism able to survive prolonged desiccation and high doses of ionising radiation S. Sommer and M. Toueille; 23. Molecular effects of UV and ionizing

  9. Multiple origins of asteroid pairs

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.

    2016-01-01

    Rotationally fissioned asteroids produce unbound asteroid pairs that have very similar heliocentric orbits. Backward integration of their current heliocentric orbits provides an age of closest proximity that can be used to date the rotational fission event. Most asteroid pairs follow a predicted theoretical relationship between the primary spin period and the mass ratio of the two pair members that is a direct consequence of the YORP-induced rotational fission hypothesis. If the progenitor asteroid has strength, asteroid pairs may have higher mass ratios or faster rotating primaries. However, the process of secondary fission leaves the originally predicted trend unaltered. We also describe the characteristics of pair members produced by four alternative routes from a rotational fission event to an asteroid pair. Unlike direct formation from the event itself, the age of closest proximity of these pairs cannot generally be used to date the rotational fission event since considerable time may have passed.

  10. Evolutionary Origins of Rhizarian Parasites.

    PubMed

    Sierra, Roberto; Cañas-Duarte, Silvia J; Burki, Fabien; Schwelm, Arne; Fogelqvist, Johan; Dixelius, Christina; González-García, Laura N; Gile, Gillian H; Slamovits, Claudio H; Klopp, Christophe; Restrepo, Silvia; Arzul, Isabelle; Pawlowski, Jan

    2016-04-01

    The SAR group (Stramenopila, Alveolata, Rhizaria) is one of the largest clades in the tree of eukaryotes and includes a great number of parasitic lineages. Rhizarian parasites are obligate and have devastating effects on commercially important plants and animals but despite this fact, our knowledge of their biology and evolution is limited. Here, we present rhizarian transcriptomes from all major parasitic lineages in order to elucidate their evolutionary relationships using a phylogenomic approach. Our results suggest that Ascetosporea, parasites of marine invertebrates, are sister to the novel clade Apofilosa. The phytomyxean plant parasites branch sister to the vampyrellid algal ectoparasites in the novel clade Phytorhiza. They also show that Ascetosporea + Apofilosa + Retaria + Filosa + Phytorhiza form a monophyletic clade, although the branching pattern within this clade is difficult to resolve and appears to be model-dependent. Our study does not support the monophyly of the rhizarian parasitic lineages (Endomyxa), suggesting independent origins for rhizarian animal and plant parasites. PMID:26681153

  11. On the origin of Triton

    NASA Astrophysics Data System (ADS)

    Celebonovic, V.

    1986-01-01

    The origin of Triton, based on the theory of materials under high pressure by Savic and Kasanin (1962, 1965), is described. The mean molecular weight (A) and the volume of one gram mole of Triton's material (V) are evaluated using its values of mass and radius; it is calculated that A = 67 + or - 2 and V = 3 + or - 2. These values are compared with Celebonovic's (1983) model of Neptune; it is observed that the mean molecular weight of Triton is ten times larger than Neptune's. The cause of this large variation in chemical composition is investigated. It is hypothesized that Triton and Neptune formed in different regions of the solar system, and that Triton was ejected from its primordial orbit and was later captured by Neptune.

  12. Magnetars: Properties, Origin and Evolution

    NASA Astrophysics Data System (ADS)

    Mereghetti, Sandro; Pons, José A.; Melatos, Andrew

    2015-10-01

    Magnetars are neutron stars in which a strong magnetic field is the main energy source. About two dozens of magnetars, plus several candidates, are currently known in our Galaxy and in the Magellanic Clouds. They appear as highly variable X-ray sources and, in some cases, also as radio and/or optical pulsars. Their spin periods (2-12 s) and spin-down rates (˜10-13-10-10 s s-1) indicate external dipole fields of ˜1013-15 G, and there is evidence that even stronger magnetic fields are present inside the star and in non-dipolar magnetospheric components. Here we review the observed properties of the persistent emission from magnetars, discuss the main models proposed to explain the origin of their magnetic field and present recent developments in the study of their evolution and connection with other classes of neutron stars.

  13. Origins of life systems chemistry

    NASA Astrophysics Data System (ADS)

    Sutherland, J.

    2015-10-01

    By reconciling previously conflicting views about the origin of life - in which one or other cellular subsystem emerges first, and then 'invents' the others - a new modus operandi for its study is suggested. Guided by this, a cyanosulfidic protometabolism is uncovered which uses UV light and the stoichiometric reducing power of hydrogen sulfide to convert hydrogen cyanide, and a couple of other prebiotic feedstock molecules which can be derived therefrom, into nucleic acid, peptide and lipid building blocks. Copper plays several key roles in this chemistry, thus, for example, copper(I) catalysed cross coupling and copper(II) driven oxidative crosscoupling reactions generate key feedstock molecules. Geochemical scenarios consistent with this protometabolism are outlined. Finally, the transition of a system from the inanimate to the animate state is considered in the context of there being intermediate stages of partial 'aliveness'.

  14. The evolutionary origins of friendship.

    PubMed

    Seyfarth, Robert M; Cheney, Dorothy L

    2012-01-01

    Convergent evidence from many species reveals the evolutionary origins of human friendship. In horses, elephants, hyenas, dolphins, monkeys, and chimpanzees, some individuals form friendships that last for years. Bonds occur among females, among males, or between males and females. Genetic relatedness affects friendships. In species where males disperse, friendships are more likely among females. If females disperse, friendships are more likely among males. Not all friendships, however, depend on kinship; many are formed between unrelated individuals. Friendships often involve cooperative interactions that are separated in time. They depend, at least in part, on the memory and emotions associated with past interactions. Applying the term "friendship" to animals is not anthropomorphic: Many studies have shown that the animals themselves recognize others' relationships. Friendships are adaptive. Male allies have superior competitive ability and improved reproductive success; females with the strongest, most enduring friendships experience less stress, higher infant survival, and live longer. PMID:21740224

  15. The origin of cellular life

    NASA Technical Reports Server (NTRS)

    Ingber, D. E.

    2000-01-01

    This essay presents a scenario of the origin of life that is based on analysis of biological architecture and mechanical design at the microstructural level. My thesis is that the same architectural and energetic constraints that shape cells today also guided the evolution of the first cells and that the molecular scaffolds that support solid-phase biochemistry in modern cells represent living microfossils of past life forms. This concept emerged from the discovery that cells mechanically stabilize themselves using tensegrity architecture and that these same building rules guide hierarchical self-assembly at all size scales (Sci. Amer 278:48-57;1998). When combined with other fundamental design principles (e.g., energy minimization, topological constraints, structural hierarchies, autocatalytic sets, solid-state biochemistry), tensegrity provides a physical basis to explain how atomic and molecular elements progressively self-assembled to create hierarchical structures with increasingly complex functions, including living cells that can self-reproduce.

  16. The origin of electrochemical nomenclature.

    PubMed

    Giddens, W R

    2001-09-01

    This article is about the origin and development of certain words that are important in the vocabulary of all physicians and scientists. The words that make up the electrochemical nomenclature were created in 1833 by Michael Faraday and several of his friends. Terms such as electrolyte, ion, and electrode were invented in a fashion that ignored theory but fitted the experimental facts of the laboratory. This nomenclature, derived from Greek, was so accurate and functional that is has been completely incorporated into modern chemistry, a fact that seems remarkable since the structure of the atom was completely unknown at the time. To fully develop the etymology of these words, the life of Faraday is summarized and the deliberations of the men involved are reviewed. PMID:11686262

  17. Huge waves of meteorite origin

    NASA Astrophysics Data System (ADS)

    Pelinovsky, Efim; Kozelkov, Andrey; Kurkin, Andrey

    2016-04-01

    Asteroid and meteorite risk is now actively investigated in various aspects. If the meteorite falls in the ocean it can generate huge waves with heights exceeded 10 m. For whole history about 10-20 events related with entry of meteorite in water are known. The last event occurred on February 15, 2013 when the meteorite exploded in sky of Chelyabinsk (Russia) and its big piece entered in the Chebarkul Lake. Very often, huge waves of meteorite origin are computed using the conception of equivalent (parametrical) source, whose parameters are determined through meteorite characteristics. Recently, direct methods based on numerical simulations of the Reynolds-averaged Navier-Stokes equations (RANS) have been applied to study wave processes generated by the entry of meteorite. These approaches and their applications to the historic events are discussed in paper.

  18. Evolutionary origin of cardiac malformations.

    PubMed

    Taussig, H B

    1988-10-01

    The author has proposed in previous publications that isolated cardiac malformations have an evolutionary origin. This is partly supported by the fact that isolated cardiac malformations found in humans occur also in other placental mammals as well as in birds. External gross examination of the heart in just over 5,000 birds was carried out during a 3 year period. Anomalies included one instance of duplicate hearts, two specimens in which no heart could be identified and in a fourth, a yellow-rumped warbler, the heart lay in the neck outside of the thoracic cavity. Published reports of similar occurrences of an ectopically placed heart concern birds, cattle and humans. The fact that various species of both placental mammals and birds show evidence of heritability for heart defects, and that these species cannot interbreed, combined with the fact that birds and mammals have many similar malformations, points to either a common external causative factor or a common origin. Genes that code the malformed heart must be transmitted with that part of the genetic makeup common to all birds and mammals. Malformations caused by teratogens produce widespread organ injury to a potentially normal embryo whereas the evolutionary malformation is an organ-specific anomaly in an otherwise normal mammal or bird and occurs in widely separated species. The implications of this theory are important for parents of children with an isolated congenital heart defect who may have ingested one or another drug or chemical or have been exposed to toxins or infectious agents before or after conception of the affected offspring. PMID:3047192

  19. Impact origin of the Moon

    SciTech Connect

    Slattery, W.L.

    1998-12-31

    A few years after the Apollo flights to the Moon, it became clear that all of the existing theories on the origin of the Moon would not satisfy the growing body of constraints which appeared with the data gathered by the Apollo flights. About the same time, researchers began to realize that the inner (terrestrial) planets were not born quietly -- all had evidences of impacts on their surfaces. This fact reinforced the idea that the planets had formed by the accumulation of planetesimals. Since the Earth`s moon is unique among the terrestrial planets, a few researchers realized that perhaps the Moon originated in a singular event; an event that was quite probable, but not so probable that one would expect all the terrestrial planets to have a large moon. And thus was born the idea that a giant impact formed the Moon. Impacts would be common in the early solar system; perhaps a really large impact of two almost fully formed planets of disparate sizes would lead to material orbiting the proto-earth, a proto-moon. This idea remained to be tested. Using a relatively new, but robust, method of doing the hydrodynamics of the collision (Smoothed-Particle Hydrodynamics), the author and his colleagues (W. Benz, Univ. of Arizona, and A.G.W. Cameron, Harvard College Obs.) did a large number of collision simulations on a supercomputer. The author found two major scenarios which would result in the formation of the Moon. The first was direct formation; a moon-sized object is boosted into orbit by gravitational torques. The second is when the orbiting material forms a disk, which, with subsequent evolution can form the Moon. In either case the physical and chemical properties of the newly formed Moon would very neatly satisfy the physical and chemical constraints of the current Moon. Also, in both scenarios the surface of the Earth would be quite hot after the collision. This aspect remains to be explored.

  20. Gene losses during human origins.

    PubMed

    Wang, Xiaoxia; Grus, Wendy E; Zhang, Jianzhi

    2006-03-01

    Pseudogenization is a widespread phenomenon in genome evolution, and it has been proposed to serve as an engine of evolutionary change, especially during human origins (the "less-is-more" hypothesis). However, there has been no comprehensive analysis of human-specific pseudogenes. Furthermore, it is unclear whether pseudogenization itself can be selectively favored and thus play an active role in human evolution. Here we conduct a comparative genomic analysis and a literature survey to identify 80 nonprocessed pseudogenes that were inactivated in the human lineage after its separation from the chimpanzee lineage. Many functions are involved among these genes, with chemoreception and immune response being outstandingly overrepresented, suggesting potential species-specific features in these aspects of human physiology. To explore the possibility of adaptive pseudogenization, we focus on CASPASE12, a cysteinyl aspartate proteinase participating in inflammatory and innate immune response to endotoxins. We provide population genetic evidence that the nearly complete fixation of a null allele at CASPASE12 has been driven by positive selection, probably because the null allele confers protection from severe sepsis. We estimate that the selective advantage of the null allele is about 0.9% and the pseudogenization started shortly before the out-of-Africa migration of modern humans. Interestingly, two other genes related to sepsis were also pseudogenized in humans, possibly by selection. These adaptive gene losses might have occurred because of changes in our environment or genetic background that altered the threat from or response to sepsis. The identification and analysis of human-specific pseudogenes open the door for understanding the roles of gene losses in human origins, and the demonstration that gene loss itself can be adaptive supports and extends the "less-is-more" hypothesis. PMID:16464126

  1. 5 CFR 2500.3 - Original classification.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2500.3 Administrative Personnel OFFICE OF ADMINISTRATION, EXECUTIVE OFFICE OF THE PRESIDENT INFORMATION SECURITY REGULATION § 2500.3 Original classification. No one in the Office of Administration has been granted authority for original classification of information....

  2. The interplanetary superhighway and the Origins Program

    NASA Technical Reports Server (NTRS)

    Lo, M. W.

    2002-01-01

    The origin of the universe and of life itself have been central to human inquiries since the dawn of consciousness. To develop and use the technologies to answer these timeless and profound questions is the mission of NASA's Origins Program.

  3. 2009 Swine Flu Originated in Mexico

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_159679.html 2009 Swine Flu Originated in Mexico Genetic analysis pinpoints source ... FRIDAY, July 1, 2016 (HealthDay News) -- The 2009 swine flu pandemic originated in pigs in a small ...

  4. The Origin of the Chemical Elements, 1

    ERIC Educational Resources Information Center

    Selbin, Joel

    1973-01-01

    The problem of the origin is inextricably interwoven with such matters as the origin of the universe, the structure and evolution of galaxies, stars and other astronomical objects, and with nuclear physics. (Author/DF)

  5. 5 CFR 2500.3 - Original classification.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2500.3 Administrative Personnel OFFICE OF ADMINISTRATION, EXECUTIVE OFFICE OF THE PRESIDENT INFORMATION SECURITY REGULATION § 2500.3 Original classification. No one in the Office of Administration has been granted authority for original classification of information....

  6. Ambient neutrons of natural origin

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Martin, Inacio; Shkevov, Rumen; Alves, Mauro

    2016-07-01

    The laboratory of environmental radiation of ITA (São José dos Campos, 23°11'11″S, 45°52'43″W, 650 MAMSL) performs simultaneous monitoring of a natural radiation background and meteorological parameters. Neutron flux in the energy range of 0.02 eV - 10 MeV is registered with two sets of proportional ^{3}He tubes placed into cylindrical paraffin thermalizers: an {bf outdoor detector }of 250 cm² area and {bf indoor detector }of 70 cm² area located on the second floor of a concrete building. The counter efficiency for thermal neutrons is 80%. The characteristics of the observed flux variation are quite different from those inherent to the neutrons of the cosmic ray origin. {bf Four types of the outdoor flux variations }are observed: 1) {bf seasonal }with a maxima in wet seasons; 2) {bf diurnal }with maximum at about 6 h local time and an amplitude up to several dozens; 3) {bf abrupt transient} ( 1 min) increases with magnitudes up to two orders higher than the mean daily flux; 4) short (several days) {bf quasi-periodic enhancements }with amplitudes up to several times higher than the mean daily flux. A large variation of the outdoor flux and its phase synchronism with that of the radon decay products means with a high probability their common origin. An apparent source of the neutrons observed is nuclear reactions of decay α-particles with the ground matter. In this case the dynamics of the outdoor flux variations of the first two types is controlled by those of the meteorological parameters in the locality. The third type events correlate with lightning strokes in the vicinity (<200 m) of the detector. The more rare fourth type correlate neither with geomagnetic disturbances nor with meteorological phenomena and are probably a result of natural radon release from the Earth's crust triggered by minor seismological activity. The indoor flux is quite stable with a possible weak maximum at16 h not exceeding 0.1.

  7. 19 CFR 10.2014 - Originating goods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Originating goods. 10.2014 Section 10.2014 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... Rules of Origin § 10.2014 Originating goods. Except as otherwise provided in this subpart and...

  8. 7 CFR 201.14 - Origin.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origin. (a) Alfalfa, red clover, white clover, and field corn (except hybrid seed corn) shall be labeled to show: (1) The origin, if known; or (2) if the origin is not...

  9. The Origins of Competency-Based Training

    ERIC Educational Resources Information Center

    Hodge, Steven

    2007-01-01

    This article attempts to trace the origins of competency-based training (CBT), the theory of vocational education that underpins the National Training Framework in Australia. A distinction is made between societal and theoretical origins. This paper argues that CBT has its societal origins in the United States of America during the 1950s, 60s and…

  10. 22 CFR 9.4 - Original classification.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Original classification. 9.4 Section 9.4 Foreign Relations DEPARTMENT OF STATE GENERAL SECURITY INFORMATION REGULATIONS § 9.4 Original classification. (a) Definition. Original classification is the initial determination that certain information requires protection against unauthorized...

  11. Darwin's Book: On the Origin of Species

    NASA Astrophysics Data System (ADS)

    Hodge, Jonathan

    2013-09-01

    This essay is an interpretation of Charles Darwin's Origin of Species. It focuses on the contents of the Origin as Darwin intended them to be understood and the background to the work, thus revealing the originality (or otherwise) of the work.

  12. 7 CFR 201.14 - Origin.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origin. (a) Alfalfa, red clover, white clover, and field corn (except hybrid seed corn) shall be labeled to show: (1) The origin, if known; or (2) if the origin is not...

  13. 7 CFR 201.14 - Origin.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origin. (a) Alfalfa, red clover, white clover, and field corn (except hybrid seed corn) shall be labeled to show: (1) The origin, if known; or (2) if the origin is not...

  14. 7 CFR 201.5 - Origin.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... declaration of origin could not be obtained. (b) Each country shipper shall retain a copy of each declaration... 7 Agriculture 3 2010-01-01 2010-01-01 false Origin. 201.5 Section 201.5 Agriculture Regulations of... Records for Agricultural and Vegetable Seeds § 201.5 Origin. (a) The complete record for any lot of...

  15. The Origin of Runaway Stars

    NASA Astrophysics Data System (ADS)

    Hoogerwerf, R.; de Bruijne, J. H. J.; de Zeeuw, P. T.

    2000-12-01

    Milliarcsecond astrometry provided by Hipparcos and by radio observations makes it possible to retrace the orbits of some of the nearest runaway stars and pulsars to determine their site of origin. The orbits of the runaways AE Aurigae and μ Columbae and of the eccentric binary ι Orionis intersected each other ~2.5 Myr ago in the nascent Trapezium cluster, confirming that these runaways were formed in a binary-binary encounter. The path of the runaway star ζ Ophiuchi intersected that of the nearby pulsar PSR J1932+1059, ~1 Myr ago, in the young stellar group Upper Scorpius. We propose that this neutron star is the remnant of a supernova that occurred in a binary system that also contained ζ Oph and deduce that the pulsar received a kick velocity of ~350 km s-1 in the explosion. These two cases provide the first specific kinematic evidence that both mechanisms proposed for the production of runaway stars, the dynamical ejection scenario and the binary-supernova scenario, operate in nature.

  16. Origin and properties of GEMS

    SciTech Connect

    Dai, Z R; Bradley, J P

    2006-04-11

    GEMS are to the outer solar system what chondrules are to the inner solar system. Ten years after it was first proposed that GEMS are the long-sought interstellar amorphous silicates, ion microprobe measurements have confirmed that some of them are indeed interstellar amorphous silicates. The new challenges are to obtain even higher precision isotope measurements from these submicrometer-sized objects and to clarify how and where they originally formed. Individual GEMS exhibit a strikingly narrow (0.1-0.5 {micro}m diameter) size distribution and they are systematically depleted from solar abundances in S/Si, Mg/Si, Ca/Si and Fe/Si, implying that they formed by a common mechanism. Mineralogical and petrographic evidence suggest that irradiation processing may be that mechanism. Recent nanometer-scale compositional mapping using new-generation transmission electron microscopes reveals that truly pristine GEMS may be relatively rare and new metrics need to be developed to distinguish the primordial properties of GEMS from more recent secondary alteration effects.

  17. On the Origin of Sequence.

    PubMed

    Gulik, Peter T S van der

    2015-01-01

    Three aspects which make planet Earth special, and which must be taken in consideration with respect to the emergence of peptides, are the mineralogical composition, the Moon which is in the same size class, and the triple environment consisting of ocean, atmosphere, and continent. GlyGly is a remarkable peptide because it stimulates peptide bond formation in the Salt-Induced Peptide Formation reaction. The role glycine and aspartic acid play in the active site of RNA polymerase is remarkable too. GlyGly might have been the original product of coded peptide synthesis because of its importance in stimulating the production of oligopeptides with a high aspartic acid content, which protected small RNA molecules by binding Mg2+ ions. The feedback loop, which is closed by having RNA molecules producing GlyGly, is proposed as the essential element fundamental to life. Having this system running, longer sequences could evolve, gradually solving the problem of error catastrophe. The basic structure of the standard genetic code (8 fourfold degenerate codon boxes and 8 split codon boxes) is an example of the way information concerning the emergence of life is frozen in the biological constitution of organisms: the structure of the code contains historical information. PMID:26580656

  18. Human origins: Out of Africa

    PubMed Central

    Tattersall, Ian

    2009-01-01

    Our species, Homo sapiens, is highly autapomorphic (uniquely derived) among hominids in the structure of its skull and postcranial skeleton. It is also sharply distinguished from other organisms by its unique symbolic mode of cognition. The fossil and archaeological records combine to show fairly clearly that our physical and cognitive attributes both first appeared in Africa, but at different times. Essentially modern bony conformation was established in that continent by the 200–150 Ka range (a dating in good agreement with dates for the origin of H. sapiens derived from modern molecular diversity). The event concerned was apparently short-term because it is essentially unanticipated in the fossil record. In contrast, the first convincing stirrings of symbolic behavior are not currently detectable until (possibly well) after 100 Ka. The radical reorganization of gene expression that underwrote the distinctive physical appearance of H. sapiens was probably also responsible for the neural substrate that permits symbolic cognition. This exaptively acquired potential lay unexploited until it was “discovered” via a cultural stimulus, plausibly the invention of language. Modern humans appear to have definitively exited Africa to populate the rest of the globe only after both their physical and cognitive peculiarities had been acquired within that continent. PMID:19805256

  19. Tuberculosis origin: The Neolithic scenario.

    PubMed

    Hershkovitz, Israel; Donoghue, Helen D; Minnikin, David E; May, Hila; Lee, Oona Y-C; Feldman, Michal; Galili, Ehud; Spigelman, Mark; Rothschild, Bruce M; Bar-Gal, Gila Kahila

    2015-06-01

    This paper follows the dramatic changes in scientific research during the last 20 years regarding the relationship between the Mycobacterium tuberculosis complex and its hosts - bovids and/or humans. Once the M. tuberculosis and Mycobacterium bovis genomes were sequenced, it became obvious that the old story of M. bovis evolving into the human pathogen should be reversed, as M. tuberculosis is more ancestral than M. bovis. Nevertheless, the timescale and geographical origin remained an enigma. In the current study human and cattle bone samples were examined for evidence of tuberculosis from the site of Atlit-Yam in the Eastern Mediterranean, dating from 9250 to 8160 (calibrated) years ago. Strict precautions were used to prevent contamination in the DNA analysis, and independent centers used to confirm authenticity of findings. DNA from five M. tuberculosis genetic loci was detected and had characteristics consistent with extant genetic lineages. High performance liquid chromatography was used as an independent method of verification and it directly detected mycolic acid lipid biomarkers, specific for the M. tuberculosis complex. These, together with pathological changes detected in some of the bones, confirm the presence of the disease in the Levantine populations during the Pre-pottery Neolithic C period, more than 8000 years ago. PMID:25726364

  20. On the Origin of Sequence

    PubMed Central

    van der Gulik, Peter T. S.

    2015-01-01

    Three aspects which make planet Earth special, and which must be taken in consideration with respect to the emergence of peptides, are the mineralogical composition, the Moon which is in the same size class, and the triple environment consisting of ocean, atmosphere, and continent. GlyGly is a remarkable peptide because it stimulates peptide bond formation in the Salt-Induced Peptide Formation reaction. The role glycine and aspartic acid play in the active site of RNA polymerase is remarkable too. GlyGly might have been the original product of coded peptide synthesis because of its importance in stimulating the production of oligopeptides with a high aspartic acid content, which protected small RNA molecules by binding Mg2+ ions. The feedback loop, which is closed by having RNA molecules producing GlyGly, is proposed as the essential element fundamental to life. Having this system running, longer sequences could evolve, gradually solving the problem of error catastrophe. The basic structure of the standard genetic code (8 fourfold degenerate codon boxes and 8 split codon boxes) is an example of the way information concerning the emergence of life is frozen in the biological constitution of organisms: the structure of the code contains historical information. PMID:26580656

  1. The origin of intermediary metabolism.

    PubMed

    Morowitz, H J; Kostelnik, J D; Yang, J; Cody, G D

    2000-07-01

    The core of intermediary metabolism in autotrophs is the citric acid cycle. In a certain group of chemoautotrophs, the reductive citric acid cycle is an engine of synthesis, taking in CO(2) and synthesizing the molecules of the cycle. We have examined the chemistry of a model system of C, H, and O that starts with carbon dioxide and reductants and uses redox couples as the energy source. To inquire into the reaction networks that might emerge, we start with the largest available database of organic molecules, Beilstein on-line, and prune by a set of physical and chemical constraints applicable to the model system. From the 3.5 million entries in Beilstein we emerge with 153 molecules that contain all 11 members of the reductive citric acid cycle. A small number of selection rules generates a very constrained subset, suggesting that this is the type of reaction model that will prove useful in the study of biogenesis. The model indicates that the metabolism shown in the universal chart of pathways may be central to the origin of life, is emergent from organic chemistry, and may be unique. PMID:10859347

  2. Phylogenetic Origins of Brain Organisers

    PubMed Central

    Robertshaw, Ellen; Kiecker, Clemens

    2012-01-01

    The regionalisation of the nervous system begins early in embryogenesis, concomitant with the establishment of the anteroposterior (AP) and dorsoventral (DV) body axes. The molecular mechanisms that drive axis induction appear to be conserved throughout the animal kingdom and may be phylogenetically older than the emergence of bilateral symmetry. As a result of this process, groups of patterning genes that are equally well conserved are expressed at specific AP and DV coordinates of the embryo. In the emerging nervous system of vertebrate embryos, this initial pattern is refined by local signalling centres, secondary organisers, that regulate patterning, proliferation, and axonal pathfinding in adjacent neuroepithelium. The main secondary organisers for the AP neuraxis are the midbrain-hindbrain boundary, zona limitans intrathalamica, and anterior neural ridge and for the DV neuraxis the notochord, floor plate, and roof plate. A search for homologous secondary organisers in nonvertebrate lineages has led to controversy over their phylogenetic origins. Based on a recent study in hemichordates, it has been suggested that the AP secondary organisers evolved at the base of the deuterostome superphylum, earlier than previously thought. According to this view, the lack of signalling centres in some deuterostome lineages is likely to reflect a secondary loss due to adaptive processes. We propose that the relative evolutionary flexibility of secondary organisers has contributed to a broader morphological complexity of nervous systems in different clades. PMID:24278699

  3. The origin of intermediary metabolism

    NASA Technical Reports Server (NTRS)

    Morowitz, H. J.; Kostelnik, J. D.; Yang, J.; Cody, G. D.

    2000-01-01

    The core of intermediary metabolism in autotrophs is the citric acid cycle. In a certain group of chemoautotrophs, the reductive citric acid cycle is an engine of synthesis, taking in CO(2) and synthesizing the molecules of the cycle. We have examined the chemistry of a model system of C, H, and O that starts with carbon dioxide and reductants and uses redox couples as the energy source. To inquire into the reaction networks that might emerge, we start with the largest available database of organic molecules, Beilstein on-line, and prune by a set of physical and chemical constraints applicable to the model system. From the 3.5 million entries in Beilstein we emerge with 153 molecules that contain all 11 members of the reductive citric acid cycle. A small number of selection rules generates a very constrained subset, suggesting that this is the type of reaction model that will prove useful in the study of biogenesis. The model indicates that the metabolism shown in the universal chart of pathways may be central to the origin of life, is emergent from organic chemistry, and may be unique.

  4. Nanogranular origin of concrete creep

    PubMed Central

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-01-01

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium–silicate–hydrates (C–S–H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C–S–H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C–S–H forms: low density, high density, ultra-high density. We demonstrate that the creep rate (≈1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years. PMID:19541652

  5. The origin of intermediary metabolism

    PubMed Central

    Morowitz, Harold J.; Kostelnik, Jennifer D.; Yang, Jeremy; Cody, George D.

    2000-01-01

    The core of intermediary metabolism in autotrophs is the citric acid cycle. In a certain group of chemoautotrophs, the reductive citric acid cycle is an engine of synthesis, taking in CO2 and synthesizing the molecules of the cycle. We have examined the chemistry of a model system of C, H, and O that starts with carbon dioxide and reductants and uses redox couples as the energy source. To inquire into the reaction networks that might emerge, we start with the largest available database of organic molecules, Beilstein on-line, and prune by a set of physical and chemical constraints applicable to the model system. From the 3.5 million entries in Beilstein we emerge with 153 molecules that contain all 11 members of the reductive citric acid cycle. A small number of selection rules generates a very constrained subset, suggesting that this is the type of reaction model that will prove useful in the study of biogenesis. The model indicates that the metabolism shown in the universal chart of pathways may be central to the origin of life, is emergent from organic chemistry, and may be unique. PMID:10859347

  6. Evolutionary origins of invasive populations

    PubMed Central

    Lee, Carol Eunmi; Gelembiuk, Gregory William

    2008-01-01

    What factors shape the evolution of invasive populations? Recent theoretical and empirical studies suggest that an evolutionary history of disturbance might be an important factor. This perspective presents hypotheses regarding the impact of disturbance on the evolution of invasive populations, based on a synthesis of the existing literature. Disturbance might select for life-history traits that are favorable for colonizing novel habitats, such as rapid population growth and persistence. Theoretical results suggest that disturbance in the form of fluctuating environments might select for organismal flexibility, or alternatively, the evolution of evolvability. Rapidly fluctuating environments might favor organismal flexibility, such as broad tolerance or plasticity. Alternatively, longer fluctuations or environmental stress might lead to the evolution of evolvability by acting on features of the mutation matrix. Once genetic variance is generated via mutations, temporally fluctuating selection across generations might promote the accumulation and maintenance of genetic variation. Deeper insights into how disturbance in native habitats affects evolutionary and physiological responses of populations would give us greater capacity to predict the populations that are most likely to tolerate or adapt to novel environments during habitat invasions. Moreover, we would gain fundamental insights into the evolutionary origins of invasive populations. PMID:25567726

  7. On the Origin of Interoception.

    PubMed

    Ceunen, Erik; Vlaeyen, Johan W S; Van Diest, Ilse

    2016-01-01

    Over the course of a century, the meaning of interoception has changed from the restrictive to the inclusive. In its inclusive sense, it bears relevance to every individual via its link to emotion, decision making, time-perception, health, pain, and various other areas of life. While the label for the perception of the body state changes over time, the need for an overarching concept remains. Many aspects can make any particular interoceptive sensation unique and distinct from any other interoceptive sensation. This can range from the sense of agency, to the physical cause of a sensation, the ontogenetic origin, the efferent innervation, and afferent pathways of the tissue involved amongst others. In its overarching meaning, interoception primarily is a product of the central nervous system, a construct based on an integration of various sources, not per se including afferent information. This paper proposes a definition of interoception as based on subjective experience, and pleas for the use of specific vocabulary in addressing the many aspects that contribute to it. PMID:27242642

  8. Endosymbiotic theory for organelle origins.

    PubMed

    Zimorski, Verena; Ku, Chuan; Martin, William F; Gould, Sven B

    2014-12-01

    Endosymbiotic theory goes back over 100 years. It explains the similarity of chloroplasts and mitochondria to free-living prokaryotes by suggesting that the organelles arose from prokaryotes through (endo)symbiosis. Gene trees provide important evidence in favour of symbiotic theory at a coarse-grained level, but the finer we get into the details of branches in trees containing dozens or hundreds of taxa, the more equivocal evidence for endosymbiotic events sometimes becomes. It seems that either the interpretation of some endosymbiotic events are wrong, or something is wrong with the interpretations of some gene trees having many leaves. There is a need for evidence that is independent of gene trees and that can help outline the course of symbiosis in eukaryote evolution. Protein import is the strongest evidence we have for the single origin of chloroplasts and mitochondria. It is probably also the strongest evidence we have to sort out the number and nature of secondary endosymbiotic events that have occurred in evolution involving the red plastid lineage. If we relax our interpretation of individual gene trees, endosymbiotic theory can tell us a lot. PMID:25306530

  9. On the origin of Laurentia

    SciTech Connect

    Dalziel, I.W.D. . Inst. for Geophysics)

    1992-01-01

    Laurentia, the Precambrian core of the North American continent, is surrounded by late Precambrian rift systems and therefore constitutes a suspect terrane''. A geometric and geological fit can be achieved between the Atlantic margin of Laurentia and the Pacific margin of the Gondwana craton. The enigmatic Arequipa massif along the southern Peruvian coast, that yields ca. 2.0 Ga radiometric ages, is juxtaposed with the Makkovik-Ketilidian province of the same age range in Labrador and southern Greenland. The Greenville belt continues beneath the ensialic Andes of the present day to join up with the 1.3--1.0 Ga San Ignacio and Sonsas-Aguapei orogens of the Transamazonian craton. Together with the recent identification of possible continuations of the Greenville orogen in East Antarctica and of the Taconic Appalachians in southern South America, the fit supports suggestions that Laurentia originated between East Antarctica-Australia and embryonic South America prior to the opening of the Pacific Ocean basin and amalgamation of the Gondwana Cordilleran and Appalachian margins, this implies that there may have been two supercontinents during the Neoproterozoic, before and after opening of the Pacific Ocean. As Laurentia and Gondwana appear to have collided on at least two occasions during the Paleozoic, this scenario therefore calls to question the existence of so-called supercontinental cycles. The Arica bight of the present day may reflect a primary reentrant in the South American continental margin that controlled subduction processes along the Andean margin and eventually led to uplift of the Altiplano.

  10. Nanogranular origin of concrete creep.

    PubMed

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-06-30

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium-silicate-hydrates (C-S-H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C-S-H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C-S-H forms: low density, high density, ultra-high density. We demonstrate that the creep rate ( approximately 1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years. PMID:19541652

  11. Tectonic earthquakes of anthropogenic origin

    NASA Astrophysics Data System (ADS)

    Adushkin, V. V.

    2016-03-01

    The enhancement of seismicity induced by industrial activity in Russia in the conditions of present-day anthropization is noted. In particular, the growth in the intensity and number of strong tectonic earthquakes with magnitudes M ≥ 3 (seismic energy 109 J) due to human activity is revealed. These man-made tectonic earthquakes have started to occur in the regions of the East European Platform which were previously aseismic. The development of such seismicity is noted in the areas of intense long-term mineral extraction due to the increasing production depth and extended mining and production. The mechanisms and generation conditions of man-made tectonic earthquakes in the anthropogenically disturbed medium with the changed geodynamical and fluid regime is discussed. The source zones of these shallow-focus tectonic earthquakes of anthropogenic origin are formed in the setting of stress state rearrangement under anthropogenic loading both near these zones and at a significant distance from them. This distance is determined by the tectonic structure of the rock mass and the character of its energy saturation, in particular, by the level of the formation pressure or pore pressure. These earthquakes occur at any time of the day, have a triggered character, and are frequently accompanied by catastrophic phenomena in the underground mines and on the surface due to the closeness to the source zones.

  12. On the Origin of Interoception

    PubMed Central

    Ceunen, Erik; Vlaeyen, Johan W. S.; Van Diest, Ilse

    2016-01-01

    Over the course of a century, the meaning of interoception has changed from the restrictive to the inclusive. In its inclusive sense, it bears relevance to every individual via its link to emotion, decision making, time-perception, health, pain, and various other areas of life. While the label for the perception of the body state changes over time, the need for an overarching concept remains. Many aspects can make any particular interoceptive sensation unique and distinct from any other interoceptive sensation. This can range from the sense of agency, to the physical cause of a sensation, the ontogenetic origin, the efferent innervation, and afferent pathways of the tissue involved amongst others. In its overarching meaning, interoception primarily is a product of the central nervous system, a construct based on an integration of various sources, not per se including afferent information. This paper proposes a definition of interoception as based on subjective experience, and pleas for the use of specific vocabulary in addressing the many aspects that contribute to it. PMID:27242642

  13. First hyperpolarizabilities of 1,3,5-tricyanobenzene derivatives: origin of larger beta values for the octupoles than for the dipoles.

    PubMed

    Lee, Sang Hae; Park, Jo Ryoung; Jeong, Mi-Yun; Kim, Hwan Myung; Li, Shaojun; Song, Jongwon; Ham, Sihyun; Jeon, Seung-Joon; Cho, Bong Rae

    2006-01-16

    A series of donor-acceptor substituted stilbene and diphenylacetylene derivatives and their octupolar analogues have been synthesized and the linear and nonlinear optical properties (beta) studied by both experiments and theoretical calculation. The lambda(max) of the dipoles increases with the conjugation length and is always larger when the C=C bond is used, instead of the C[triple bond]C bond, as the conjugation bridge. Although the lambda(max) values of the octupoles show no clear trend, they are much larger than those of the dipoles. The beta(0) values of the dipoles increase with conjugation length and as the conjugation bridge is changed from the C[triple bond]C to C=C bond. This increase is accompanied by an increase in either lambda(max) or the oscillator strength. Similarly, the beta(0) values of the octupoles increase with the conjugation length and with a change in the donor in the order: NEt2 < N(i-amyl)Ph < NPh2. Moreover, beta(yyy)/beta(zzz) ratios are in the range of 1.6-3.9 and decrease with the conjugation length. Beta values calculated by the finite-field and sum-over-states methods are in good agreement with the experimental data. Also, there is a parallel relationship between the calculated beta values and bond length alternation (BLA). From these results, the origin of the larger beta values for octupoles than for dipoles is assessed. PMID:16323225

  14. Cosmic Origin and Theology of the Revelation

    NASA Astrophysics Data System (ADS)

    Guijarro, José Francisco

    2007-04-01

    All along cultural history man has asked himself about the origin of man, the origin of life ante the origin of the cosmos. Regarding the question about the origin of the cosmos, any theological research must settle before any other goal the question of its language: what we understand as scientific, mythical or theological language. The biblical texts on Creation are analyzed in their historical, cultural and theological context. It is concluded that the fundamental religious meanings of the biblical texts are not in opposition to scientific interpretation of cosmic origin.

  15. [The origin of informed consent].

    PubMed

    Mallardi, V

    2005-10-01

    The principle of informed consent, aimed at the lawfulness of health assistance, tends to reflect the concept of autonomy and of decisional autodetermination of the person requiring and requesting medical and/or surgical interventions. This legal formula, over the last few years, has gained not only considerable space but also importance in the doctrinal elaboration and approaches, as well as juridical interpretations, thereby influencing the everyday activities of the medical profession. Informed consent is still the object of continuous explorations, not only asfar as concerns the already confirmed theoretical profile but, instead, the ambiguous practical and consequential aspect. Analysing how the concept and role of consensus was born and developed with the more adequate and reasonable excursions to make it valid and obtain it, it is impossible not to take into consideration, on the one hand, the very ancient philosophical origins and, on the other, the fact that it was conditioned by religion with the moral aspects and the accelerated deontological evolution with pathways parallel to the needs and the progress offered by new forms of treatment and novel biotechnological applications. The principle of consent is a relatively new condition. In fact, already in the times of not only the Egyptian civilisation, but also the Greek and Roman, documents have been found which show how the doctor's intervention had, in some way, first to be approved by the patient. Plato (law IV) had already foreseen the problems, the procedures and the modes of information which are, in synthesis, at the root of the principles of the present formula of informed consent and correlated the practice of the information and consensus with the quality and social position of the patient. The only guarantee that the patient might have, derived from a fundamental principle of medicine of all times: "in disease, focus on two aims, to improve and not to cause damage". A figure can be recognised

  16. Unique origin of the cystic artery.

    PubMed

    Hlaing, K P P; Thwin, S S; Shwe, N

    2011-12-01

    The cystic artery (CA) is known to exhibit variations in its origin and branching pattern. This is attributed to the developmental changes occurring in the primitive ventral splanchnic arteries. During routine dissection of a male cadaver, we observed that the CA originated from the middle hepatic artery (MHA) at a distance of about 1 cm from its origin, and the MHA originated from the right hepatic artery at a distance of 2.1 cm from its origin. The CA traversed for a distance of 1.5 cm, giving off a branch to the cystic duct. It then passed anterior to the cystic duct. The origin of the CA was located to the left of the common hepatic duct, outside the Calot's triangle. The topographical anatomy of the arterial system of the hepatobiliary region and their anomalous origin should be considered during hepatobiliary surgeries. This knowledge is also important for interventional radiologists in routine clinical practice. PMID:22159949

  17. Fascia Origin of Adipose Cells.

    PubMed

    Su, Xueying; Lyu, Ying; Wang, Weiyi; Zhang, Yanfei; Li, Danhua; Wei, Suning; Du, Congkuo; Geng, Bin; Sztalryd, Carole; Xu, Guoheng

    2016-05-01

    Adipocytes might arise from vascular stromal cells, pericytes and endothelia within adipose tissue or from bone marrow cells resident in nonadipose tissue. Here, we identified adipose precursor cells resident in fascia, an uninterrupted sheet of connective tissue that extends throughout the body. The cells and fragments of superficial fascia from the rat hindlimb were highly capable of spontaneous and induced adipogenic differentiation but not myogenic and osteogenic differentiation. Fascial preadipocytes expressed multiple markers of adipogenic progenitors, similar to subcutaneous adipose-derived stromal cells (ASCs) but discriminative from visceral ASCs. Such preadipocytes resided in fascial vasculature and were physiologically active in vivo. In growing rats, adipocytes dynamically arose from the adventitia to form a thin adipose layer in the fascia. Later, some adipocytes appeared to overlay on top of other adipocytes, an early sign for the formation of three-dimensional adipose tissue in fascia. The primitive adipose lobules extended invariably along blood vessels toward the distal fascia areas. At the lobule front, nascent capillaries wrapped and passed ahead of mature adipocytes to form the distal neovasculature niche, which might replenish the pool of preadipocytes and supply nutrients and hormones necessary for continuous adipogenesis. Our findings suggest a novel model for the origin of adipocytes from the fascia, which explains both neogenesis and expansion of adipose tissue. Fascial preadipocytes generate adipose cells to form primitive adipose lobules in superficial fascia, a subcutaneous nonadipose tissue. With continuous adipogenesis, these primitive adipose lobules newly formed in superficial fascia may be the rudiment of subcutaneous adipose tissue. Stem Cells 2016;34:1407-1419. PMID:26867029

  18. The origin of ambling horses.

    PubMed

    Wutke, Saskia; Andersson, Leif; Benecke, Norbert; Sandoval-Castellanos, Edson; Gonzalez, Javier; Hallsson, Jón Hallsteinn; Lõugas, Lembi; Magnell, Ola; Morales-Muniz, Arturo; Orlando, Ludovic; Pálsdóttir, Albína Hulda; Reissmann, Monika; Muñoz-Rodríguez, Mariana B; Ruttkay, Matej; Trinks, Alexandra; Hofreiter, Michael; Ludwig, Arne

    2016-08-01

    Horseback riding is the most fundamental use of domestic horses and has had a huge influence on the development of human societies for millennia. Over time, riding techniques and the style of riding improved. Therefore, horses with the ability to perform comfortable gaits (e.g. ambling or pacing), so-called 'gaited' horses, have been highly valued by humans, especially for long distance travel. Recently, the causative mutation for gaitedness in horses has been linked to a substitution causing a premature stop codon in the DMRT3 gene (DMRT3_Ser301STOP) [1]. In mice, Dmrt3 is expressed in spinal cord interneurons and plays an important role in the development of limb movement coordination [1]. Genotyping the position in 4396 modern horses from 141 breeds revealed that nowadays the mutated allele is distributed worldwide with an especially high frequency in gaited horses and breeds used for harness racing [2]. Here, we examine historic horse remains for the DMRT3 SNP, tracking the origin of gaitedness to Medieval England between 850 and 900 AD. The presence of the corresponding allele in Icelandic horses (9(th)-11(th) century) strongly suggests that ambling horses were brought from the British Isles to Iceland by Norse people. Considering the high frequency of the ambling allele in early Icelandic horses, we believe that Norse settlers selected for this comfortable mode of horse riding soon after arrival. The absence of the allele in samples from continental Europe (including Scandinavia) at this time implies that ambling horses may have spread from Iceland and maybe also the British Isles across the continent at a later date. PMID:27505236

  19. On the origin of EDSS.

    PubMed

    Kurtzke, John F

    2015-03-01

    The origin of EDSS, the Expanded Disability Status Scale for multiple sclerosis, was some 30 years before its only publication in 1983 when we were trying to assess a potential treatment and found no published methods. Findings from the complete neurologic examinations in over 200 patients were consolidated into mutually exclusive but all-inclusive neurophysiologic entities called Functional Systems (FS), and these provided the basis for an 11 step 0-10 rank order scale, the Disability Status Scale (DSS). This was used successfully, as well as in the first two Class I treatment trials performed, with the second one also incorporating the 8 FS. Both measures were part of an assessment of a natural history series derived from men hospitalized for MS in the US Army in World War II and followed for some 20 years. Describing each of the 8 FS as affected (1) or normal (0) defined 256 possible patterns of involvement for all patients. Half the patients at diagnosis had one of the 14 most common patterns. Each FS worsened in frequency and severity of involvement in correlation with the DSS, which overall showed a unimodal distribution, until in another series of patients 16 years post onset bimodality first appeared. Observations that the 11 step DSS might have too few steps for treatment trials led to the EDSS of 20 steps with each grade between 1 and 9 divided into two. The system of EDSS+FS to summarize all the CNS involvement as defined by objective findings on neurologic examination thereafter remained unchanged to the present. I just learned that the unpublished system copyrighted in Switzerland as "neurostatus" has been called and referenced as my EDSS. It is not. PMID:25787185

  20. Origin of Small Tectonic Plates

    NASA Astrophysics Data System (ADS)

    Mallard, C.; Coltice, N.; Seton, M.; Müller, D.; Tackley, P.

    2015-12-01

    The plate tectonic theory allowed to split the Earth surface into 6 (Le Pichon 1968) to 52 tectonic plates (Bird 2003). These plates are separated into two groups: the first of 7 large plates and the second of numerous smaller plates (Morra et al 2013). Previous studies using the reconstruction of the past 200 My, suggest that the size of large plates is driven by mantle flow. But the tools employed are descriptive (Morra et al 2013, Sornette and Pisarenko 2003), hence ignoring forces and physical principles within the lithosphere and the mantle. The processes at the origin of small plates remain unknown. We developed a new approach to explain the plate sizes. We demonstrate that the physics of convection drives it. We applied plate tectonics theory on 3D spherical convection models generating plate-like motions, which give access to a complete survey of data: velocities, viscosity and heat flow. Our data show that (1) the large plates depend on the dominating scale of the convective flow due to the initiation or the shutdown of subductions; (2) the smaller plates are generated thanks to large variability of regional stresses along subduction zone by slab pull and suction influenced by the geometry of trenches. Our results are consistent with the quick reorganizations of back-arc basins occuring synchronously with the modification of subduction zones geometry around the Pacific plate (Sdrolias et al 2004). Hence, we conclude that (1) the decreasing number of small plates in the plate reconstructions back in time is an artifact induced by their short lifetime, that is why they are artificially ignored; (2) the geometry of past trenches is simplified leading to an underestimation of the length of subduction zones.

  1. Origin of cosmic chemical abundances

    NASA Astrophysics Data System (ADS)

    Maio, Umberto; Tescari, Edoardo

    2015-11-01

    Cosmological N-body hydrodynamic computations following atomic and molecular chemistry (e-, H, H+, H-, He, He+, He++, D, D+, H2, H_2^+, HD, HeH+), gas cooling, star formation and production of heavy elements (C, N, O, Ne, Mg, Si, S, Ca, Fe, etc.) from stars covering a range of mass and metallicity are used to explore the origin of several chemical abundance patterns and to study both the metal and molecular content during simulated galaxy assembly. The resulting trends show a remarkable similarity to up-to-date observations of the most metal-poor damped Lyman α absorbers at redshift z ≳ 2. These exhibit a transient nature and represent collapsing gaseous structures captured while cooling is becoming effective in lowering the temperature below ˜ 104 K, before they are disrupted by episodes of star formation or tidal effects. Our theoretical results agree with the available data for typical elemental ratios, such as [C/O], [Si/Fe], [O/Fe], [Si/O], [Fe/H], [O/H] at redshifts z ˜ 2-7. Correlations between H I and H2 abundances show temporal and local variations and large spreads as a result of the increasing cosmic star formation activity from z ˜ 6 to 3. The scatter we find in the abundance ratios is compatible with the observational data and is explained by simultaneous enrichment by sources from different stellar phases or belonging to different stellar populations. Simulated synthetic spectra support the existence of metal-poor cold clumps with large optical depth at z ˜ 6 that could be potential Population III sites at low or intermediate redshift. The expected dust content is in line with recent determinations.

  2. Magnetofossils: Characteristics, Origins and Distribution

    NASA Astrophysics Data System (ADS)

    Vali, H.

    2005-12-01

    The term magnetofossil was introduced by Joseph Kirschvink and co-workers in the mid-eighties to describe fossil remains of magnetosomes in marine sediments after the discovery of magnetotactic bacteria by Richard Blakemore in the mid-seventies. Magnetofossils were initially considered as stable carriers of natural remanent magnetization (NRM) in sedimentary rocks. In the protracted debate over the possible bacterial origin of magnetite in carbonate in Martian meteorite ALH84001, the term magnetofossil has also been used as evidence for biological activity (i.e., biosignature) in ancient terrestrial and extraterrestrial environments. Magnetic methods sensitive to the single domain (SD) size specificity have been developed to detect the magnetosomes, distinction between biogenic and non-biogenic magnetic phases based upon magnetic analysis is difficult. In addition, with the discovery of SD magnetite formed by thermophilic bacteria isolated from deep subsurface and biogenic magnetite produced through reduction of Fe(III) by a variety of dissimilatory Fe(III)-reducing bacteria (DIRB) in diverse environments and a wide range of temperatures, new criteria has to be established to enable the distinction between biogenic and non-biogenic magnetic phases. Laboratory experiments have shown that the size and shape of magnetic phases formed by these bacteria strongly depend upon the growth culture conditions. Slight variation in the chemical composition, temperature and/or redox condition of the growth medium resulted in deviation in crystal morphology of magnetite making the morphological distinction between biogenic (magnetofossils) and non-biogenic magnetic minerals difficult. Magnetic phases with unique shape, morphology and organization have been observed in a variety of bacteria cultures. The existence of these types of magnetofossils in the natural environment, however, has not been explored. Although alternative preparation and analytical techniques have been

  3. The Doctorate as an Original Contribution to Knowledge: Considering Relationships between Originality, Creativity, and Innovation

    ERIC Educational Resources Information Center

    Baptista, Ana; Frick, Liezel; Holley, Karri; Remmik, Marvi; Tesch, Jakob; Âkerlind, Gerlese

    2015-01-01

    This article explores the meaning of originality in doctoral studies and its relationship with creativity and innovation. Doctoral theses are expected to provide an original contribution to knowledge in their field all over the world. However, originality is not well defined. Using the literature on concepts of originality as a foundation, this…

  4. COSMIC ORIGINS SPECTROGRAPH OBSERVATIONS OF WARM INTERVENING GAS AT z {approx} 0.325 TOWARD 3C 263

    SciTech Connect

    Narayanan, Anand; Savage, Blair D.; Wakker, Bart P. E-mail: savage@astro.wisc.edu

    2012-06-10

    We present HST/COS high-S/N observations of the z = 0.32566 multiphase absorber toward 3C 263. The Cosmic Origins Spectrograph (COS) data show absorption from H I (Ly{alpha} to Ly{theta}), O VI, C III, N III, Si III, and C II. The Ne VIII in this absorber is detected in the FUSE spectrum along with O III, O IV, and N IV. The low and intermediate ions are kinematically aligned with each other and H I and display narrow line widths of b {approx} 6-8 km s{sup -1}. The O VI {lambda}{lambda}1031, 1037 lines are kinematically offset by {Delta}v {approx} 12 km s{sup -1} from the low ions and are a factor of {approx}4 broader. All metal ions except O VI and Ne VIII are consistent with an origin in gas photoionized by the extragalactic background radiation. The bulk of the observed H I is also traced by this photoionized medium. The metallicity in this gas phase is Z {approx}> 0.15 Z{sub Sun} with carbon having near-solar abundances. The O VI and Ne VIII favor an origin in collisionally ionized gas at T = 5.2 Multiplication-Sign 10{sup 5} K. The H I absorption associated with this warm absorber is a broad-Ly{alpha} absorber (BLA) marginally detected in the COS spectrum. This warm gas phase has a metallicity of [X/H] {approx}-0.12 dex, and a total hydrogen column density of N( H) {approx} 3 Multiplication-Sign 10{sup 19} cm{sup -2}, which is {approx}2 dex higher than what is traced by the photoionized gas. Simultaneous detection of O VI, Ne VIII, and BLAs in an absorber can be a strong diagnostic of gas with T {approx} 10{sup 5}-10{sup 6} K corresponding to the warm phase of the warm-hot intergalactic medium or shock-heated gas in the extended halos of galaxies.

  5. Modern human origins: progress and prospects.

    PubMed Central

    Stringer, Chris

    2002-01-01

    The question of the mode of origin of modern humans (Homo sapiens) has dominated palaeoanthropological debate over the last decade. This review discusses the main models proposed to explain modern human origins, and examines relevant fossil evidence from Eurasia, Africa and Australasia. Archaeological and genetic data are also discussed, as well as problems with the concept of 'modernity' itself. It is concluded that a recent African origin can be supported for H. sapiens, morphologically, behaviourally and genetically, but that more evidence will be needed, both from Africa and elsewhere, before an absolute African origin for our species and its behavioural characteristics can be established and explained. PMID:12028792

  6. 17 CFR 200.505 - Original classification.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Original classification. 200...; CONDUCT AND ETHICS; AND INFORMATION AND REQUESTS Classification and Declassification of National Security Information and Material § 200.505 Original classification. (a) No Commission Member or employee has...

  7. Internet: A Vehicle for Original Student Research.

    ERIC Educational Resources Information Center

    Cutler-Landsman, Donna; Wrzesinski, Conrad J.

    1994-01-01

    The study described in this article investigated original student research using student-to-student telecommunications. Sixth graders gathered original data through Internet to answer their own questions about education in other countries. Student surveys and teacher observation indicated students found telecommunications highly motivating. (SM)

  8. 19 CFR 10.303 - Originating goods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Originating goods. 10.303 Section 10.303 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Canada Free Trade Agreement § 10.303 Originating goods. (a) General....

  9. Family Background Factors and Originality in Children.

    ERIC Educational Resources Information Center

    Aldous, Joan

    Results from a study of family background variables as related to third graders' performance on non-verbal tests of creativity provide suggestions to teachers concerned with creating a climate conducive to originality. Sex did not differentiate the sample, but children from large, working class families appeared less original. This was also true…

  10. The Gestural Theory of Language Origins

    ERIC Educational Resources Information Center

    Armstrong, David F.

    2008-01-01

    The idea that iconic visible gesture had something to do with the origin of language, particularly speech, is a frequent element in speculation about this phenomenon and appears early in its history. Socrates hypothesizes about the origins of Greek words in Plato's satirical dialogue, "Cratylus", and his speculation includes a possible role for…

  11. 19 CFR 10.594 - Originating goods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... States Free Trade Agreement Rules of Origin § 10.594 Originating goods. Except as otherwise provided in this subpart and General Note 29(m), HTSUS, a good imported into the customs territory of the...

  12. 19 CFR 10.594 - Originating goods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... States Free Trade Agreement Rules of Origin § 10.594 Originating goods. Except as otherwise provided in this subpart and General Note 29(m), HTSUS, a good imported into the customs territory of the...

  13. 19 CFR 10.594 - Originating goods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... States Free Trade Agreement Rules of Origin § 10.594 Originating goods. Except as otherwise provided in this subpart and General Note 29(m), HTSUS, a good imported into the customs territory of the...

  14. 19 CFR 10.594 - Originating goods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... States Free Trade Agreement Rules of Origin § 10.594 Originating goods. Except as otherwise provided in this subpart and General Note 29(m), HTSUS, a good imported into the customs territory of the...

  15. Origins of Small Volcanic Cones on Mars

    NASA Technical Reports Server (NTRS)

    Fagents, S. A.; Pace, K.; Greeley, R.

    2002-01-01

    Studies of volcanic cones identified in the MGS data indicate a range of possible origins, from primary vent constructs (cinder cones, tuff cones) to rootless cones formed by lava-ice interaction. Additional information is contained in the original extended abstract.

  16. Starkweather Originality Test for Young Children.

    ERIC Educational Resources Information Center

    Starkweather, Elizabeth K.

    The Starkweather Originality Test is designed to measure the creative potential of children ranging in age from 3 years, 6 months to 6 years, 6 months. Children younger than 3 years, 6 months can be given the Originality Test if their ability to communicate verbally is satisfactorily demonstrated during the pretest. The test is individually…

  17. Impacts and the origin of life

    NASA Technical Reports Server (NTRS)

    Kasting, J. F.

    1990-01-01

    As living creatures, all of us have some interest in the question of how life originated. To some, the question is more religious than scientific; nonetheless, a small but dedicated group of scientists spend their careers trying to answer it from a rational standpoint. Logically, the question can be broken down into the three standard divisions of any mystery: When did life originate? Where did it originate? And how did it originate? Of these three sub-questions the last is by far the most difficult and I will make no attempt to address it here. I will however take a personal look at the two easier parts of the problem. In particular, I will outline my current view of the physical environment of the early Earth, and I will try to show how observations of other solar system bodies, especially our own Moon, provide clues as to when and where life could have originated.

  18. The origin of turtles: a paleontological perspective.

    PubMed

    Joyce, Walter G

    2015-05-01

    The origin of turtles and their unusual body plan has fascinated scientists for the last two centuries. Over the course of the last decades, a broad sample of molecular analyses have favored a sister group relationship of turtles with archosaurs, but recent studies reveal that this signal may be the result of systematic biases affecting molecular approaches, in particular sampling, non-randomly distributed rate heterogeneity among taxa, and the use of concatenated data sets. Morphological studies, by contrast, disfavor archosaurian relationships for turtles, but the proposed alternative topologies are poorly supported as well. The recently revived paleontological hypothesis that the Middle Permian Eunotosaurus africanus is an intermediate stem turtle is now robustly supported by numerous characters that were previously thought to be unique to turtles and that are now shown to have originated over the course of tens of millions of years unrelated to the origin of the turtle shell. Although E. africanus does not solve the placement of turtles within Amniota, it successfully extends the stem lineage of turtles to the Permian and helps resolve some questions associated with the origin of turtles, in particular the non-composite origin of the shell, the slow origin of the shell, and the terrestrial setting for the origin of turtles. PMID:25712176

  19. Prediction of Saccharomyces cerevisiae replication origins

    PubMed Central

    Breier, Adam M; Chatterji, Sourav; Cozzarelli, Nicholas R

    2004-01-01

    Background Autonomously replicating sequences (ARSs) function as replication origins in Saccharomyces cerevisiae. ARSs contain the 17 bp ARS consensus sequence (ACS), which binds the origin recognition complex. The yeast genome contains more than 10,000 ACS matches, but there are only a few hundred origins, and little flanking sequence similarity has been found. Thus, identification of origins by sequence alone has not been possible. Results We developed an algorithm, Oriscan, to predict yeast origins using similarity to 26 characterized origins. Oriscan used 268 bp of sequence, including the T-rich ACS and a 3' A-rich region. The predictions identified the exact location of the ACS. A total of 84 of the top 100 Oriscan predictions, and 56% of the top 350, matched known ARSs or replication protein binding sites. The true accuracy was even higher because we tested 25 discrepancies, and 15 were in fact ARSs. Thus, 94% of the top 100 predictions and an estimated 70% of the top 350 were correct. We compared the predictions to corresponding sequences in related Saccharomyces species and found that the ACSs of experimentally supported predictions show significant conservation. Conclusions The high accuracy of the predictions indicates that we have defined near-sufficient conditions for ARS activity, the A-rich region is a recognizable feature of ARS elements with a probable role in replication initiation, and nucleotide sequence is a reliable predictor of yeast origins. Oriscan detected most origins in the genome, demonstrating previously unrecognized generality in yeast replication origins and significant discriminatory power in the algorithm. PMID:15059255

  20. The RNA World and its origins

    NASA Technical Reports Server (NTRS)

    Schwartz, A. W.

    1995-01-01

    The theory of the "RNA World" states that the first molecular systems to display the properties of self-replication and evolution were RNA molecules. The origin of life not only depended crucially upon this event, but RNA molecules can even be viewed as the first "living" things. In recent years this theory has gained ascendancy over competing ideas and is now largely accepted by biologists as the most satisfactory explanation for the origin of life. The reasons for this development will be reviewed and the problem of the origin of the first RNA molecules will be discussed.

  1. Origin and Functions of Tissue Macrophages

    PubMed Central

    Epelman, Slava; Lavine, Kory J.; Randolph, Gwendalyn J.

    2015-01-01

    Macrophages are distributed in tissues throughout the body and contribute to both homeostasis and disease. Recently, it has become evident that most adult tissue macrophages originate during embryonic development and not from circulating monocytes. Each tissue has its own composition of embryonically derived and adult-derived macrophages, but it is unclear whether macrophages of distinct origins are functionally interchangeable or have unique roles at steady state. This new understanding also prompts reconsideration of the function of circulating monocytes. Classical Ly6chi monocytes patrol the extravascular space in resting organs, and Ly6clo nonclassical monocytes patrol the vasculature. Inflammation triggers monocytes to differentiate into macrophages, but whether resident and newly recruited macrophages possess similar functions during inflammation is unclear. Here, we define the tools used for identifying the complex origin of tissue macrophages and discuss the relative contributions of tissue niche versus ontological origin to the regulation of macrophage functions during steady state and inflammation. PMID:25035951

  2. Blue Origin Conducts Pad Escape Test

    NASA Video Gallery

    Blue Origin conducted a successful pad escape test Oct. 19 at the company's West Texas launch site, firing its pusher escape motor and launching a full-scale suborbital crew capsule from a simulate...

  3. 31 CFR 538.312 - Sudanese origin.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., manufactured, grown, extracted, or processed within Sudan; (b) Goods which have entered into Sudanese commerce... United States. (e) The term goods or services of Sudanese origin does not include goods or services...

  4. The Solar System and Its Origin

    ERIC Educational Resources Information Center

    Dormand, J. R.

    1973-01-01

    Presents a brief explanation of the solar system, including planets, asteroids, satellites, comets, planetary orbits, as well as, old and recent cosmogonic theories. Indicates that man is nearer a solution to the origin of the planetary system than ever before.

  5. Blue Origin Tests BE-3 Engine

    NASA Video Gallery

    Blue Origin successfully fires the thrust chamber assembly for its new 100,000 pound thrust BE-3 liquid oxygen, liquid hydrogen rocket engine. As part of the company's Reusable Booster System (RBS)...

  6. Geochemistry and the origin of life

    NASA Technical Reports Server (NTRS)

    Kvenvolden, K. A.

    1974-01-01

    The origin of life on earth is examined from a viewpoint stressing the validity of the concept of chemical evolution. The different geological formations supporting the mechanisms of the theory are described; the stage of chemical evolution (preceding that of biological evolution) would have taken place from the time of the origin of the earth and meteorites, 4.6 billion years ago, to the early Precambrian period, about 3.2 billion years ago. Specific aspects of the problem discussed include amino acids from spark discharges and their comparison with the Murchison meteorite amino acids, the properties and theory of genesis of the carbonaceous complex within the cold Bokevelt meteorite, ammonion ion concentration in the primitive ocean, the oxygen isotope chemistry of ancient charts, the origin and rise of oxygen concentration in the earth's atmosphere, Precambrian microorganisms and evolutionary events prior to the origin of vascular plants, and biogenicity and significance of the oldest known stromatolites.

  7. An Introduction to Comets and Their Origin.

    ERIC Educational Resources Information Center

    Chapman, Robert D.; Brandt, John C.

    1985-01-01

    Presents excerpts from "The Comet Book," a nontechnical primer on comets. Various topics discusses in these excerpts include such basic information about comets as their components, paths, and origins. (DH)

  8. Anomalous biceps origin from the rotator cuff

    PubMed Central

    Banerjee, Samik; Patel, Vipul R

    2015-01-01

    Variations in the origin of the long head of biceps tendon (LHBT) have been described in literature; however, its clinical significance remains uncertain. We describe in this report, the history, physical examination and the arthroscopic findings in a patient who had an anomalous origin of the LHBT from the rotator cuff, resulting in restriction of range of motion. This anomalous origin of the long head of biceps tendon causing capsular contracture and restriction of movements leading to secondary internal impingement, has not been extensively reported in the literature. Shoulder arthroscopists should be aware that, although, an uncommon clinical condition, the aberrant congenital origin of the LHBT from the rotator cuff can rarely become pathologic in middle age and lead to shoulder dysfunction. In such cases, release of the anomalous band may be required, along with the treatment of other concomitant intraarticular pathologies in the glenohumeral joint. PMID:25593361

  9. 46 CFR 503.54 - Original classification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... FEDERAL MARITIME COMMISSION GENERAL AND ADMINISTRATIVE PROVISIONS PUBLIC INFORMATION Information Security... subject matter, or to the Information Security Oversight Office, for review and a classification... originally classify information. (b) If a Commission Member or employee develops information that appears...

  10. Geochemistry and origin of regional dolomites

    SciTech Connect

    Hanson, G.N.; Meyers, W.J.

    1992-01-01

    This grant supports research on the origins and geochemical aspects of regional dolomites. Eight graduate students are involved in research on dolomite allowing a diverse range of studies. This report outlines their work in the field. (JL)

  11. The chromatin environment shapes DNA replication origin organization and defines origin classes

    PubMed Central

    Cayrou, Christelle; Ballester, Benoit; Peiffer, Isabelle; Fenouil, Romain; Coulombe, Philippe; Andrau, Jean-Christophe; van Helden, Jacques; Méchali, Marcel

    2015-01-01

    To unveil the still-elusive nature of metazoan replication origins, we identified them genome-wide and at unprecedented high-resolution in mouse ES cells. This allowed initiation sites (IS) and initiation zones (IZ) to be differentiated. We then characterized their genetic signatures and organization and integrated these data with 43 chromatin marks and factors. Our results reveal that replication origins can be grouped into three main classes with distinct organization, chromatin environment, and sequence motifs. Class 1 contains relatively isolated, low-efficiency origins that are poor in epigenetic marks and are enriched in an asymmetric AC repeat at the initiation site. Late origins are mainly found in this class. Class 2 origins are particularly rich in enhancer elements. Class 3 origins are the most efficient and are associated with open chromatin and polycomb protein-enriched regions. The presence of Origin G-rich Repeated elements (OGRE) potentially forming G-quadruplexes (G4) was confirmed at most origins. These coincide with nucleosome-depleted regions located upstream of the initiation sites, which are associated with a labile nucleosome containing H3K64ac. These data demonstrate that specific chromatin landscapes and combinations of specific signatures regulate origin localization. They explain the frequently observed links between DNA replication and transcription. They also emphasize the plasticity of metazoan replication origins and suggest that in multicellular eukaryotes, the combination of distinct genetic features and chromatin configurations act in synergy to define and adapt the origin profile. PMID:26560631

  12. Luna 24 origins - Some trace element constraints

    NASA Technical Reports Server (NTRS)

    Jovanovic, S.; Jensen, K. J.; Reed, G. W., Jr.

    1978-01-01

    Luna 24 basaltic material originated in the particular volume of the lunar crust that produced Apollo 11 and Luna 16 basaltic material; it has the same Clr/P2O5 (r = residual) signature. Ru-Os contents (Barsukov et al., 1977) and a number of radiogenic age measurements place Luna 24 basalt origins stratigraphically in a layer between those from which Apollo 15 and Apollo 11 and 17 basalts were derived.

  13. Origin of homochirality in biological systems

    NASA Astrophysics Data System (ADS)

    Toxvaerd, S.

    2005-01-01

    Models for segregation of racemic mixtures of chiral amphiphiles and lipophiles in aqueous solutions show that the amphiphiles with active isomerization kinetics can perform a spontaneous symmetry break during the segregation and self-assemble to homochiral matter. Based on physico-chemical facts, it is argued that D-glyceraldehyde, which was synthesized from the volatiles at the hydrothermal reactors at the origin of life, could be the origin of homochirality in biological systems.

  14. Fisheries. Population of origin of Atlantic cod.

    PubMed

    Nielsen, E E; Hansen, M M; Schmidt, C; Meldrup, D; Grønkjaer, P

    2001-09-20

    Most of the world's cod (Gadus morhua) fisheries are now tightly regulated or closed altogether. Being able to link individual fish to their population of origin would assist enormously in policing regulations and in identifying poachers. Here we show that microsatellite genetic markers can be used to assign individual cod from three different populations in the northeastern Atlantic Ocean to their population of origin. PMID:11565021

  15. Original and future cometary orbits. IV

    NASA Astrophysics Data System (ADS)

    Marsden, B. G.

    1990-06-01

    The values of the 'original' and 'future' reciprocal semimajor axes are calulcated for 36 recent osculating cometary orbits. The results are compared with the computations of Yabushita and Hasegawa (1989). Adjustments for deriving original and future orbits are given for nine other recent comets for which only parabolic orbit determinations are available. Specific attention is given to the physical comet pair 1987 XXX/1988 III.

  16. Contextualising primate origins--an ecomorphological framework.

    PubMed

    Soligo, Christophe; Smaers, Jeroen B

    2016-04-01

    Ecomorphology - the characterisation of the adaptive relationship between an organism's morphology and its ecological role - has long been central to theories of the origin and early evolution of the primate order. This is exemplified by two of the most influential theories of primate origins: Matt Cartmill's Visual Predation Hypothesis, and Bob Sussman's Angiosperm Co-Evolution Hypothesis. However, the study of primate origins is constrained by the absence of data directly documenting the events under investigation, and has to rely instead on a fragmentary fossil record and the methodological assumptions inherent in phylogenetic comparative analyses of extant species. These constraints introduce particular challenges for inferring the ecomorphology of primate origins, as morphology and environmental context must first be inferred before the relationship between the two can be considered. Fossils can be integrated in comparative analyses and observations of extant model species and laboratory experiments of form-function relationships are critical for the functional interpretation of the morphology of extinct species. Recent developments have led to important advancements, including phylogenetic comparative methods based on more realistic models of evolution, and improved methods for the inference of clade divergence times, as well as an improved fossil record. This contribution will review current perspectives on the origin and early evolution of primates, paying particular attention to their phylogenetic (including cladistic relationships and character evolution) and environmental (including chronology, geography, and physical environments) contextualisation, before attempting an up-to-date ecomorphological synthesis of primate origins. PMID:26830706

  17. The number of symbiotic origins of organelles.

    PubMed

    Cavalier-Smith, T

    1992-01-01

    Mitochondria and chloroplasts both originated from bacterial endosymbionts. The available evidence strongly supports a single origin for mitochondria and only somewhat less strongly a single, slightly later, origin for chloroplasts. The arguments and evidence that have sometimes been presented in favor of the alternative theories of the multiple or polyphyletic origins of these two organelles are evaluated and the kinds of data that are needed to test more rigorously the monophyletic theory are discussed. Although chloroplasts probably originated only once, eukaryotic algae are polyphyletic because chloroplasts have been secondarily transferred to new lineages by the permanent incorporation of a photosynthetic eukaryotic algal cell into a phagotrophic protozoan host. How often this has happened is much less clear. It is particularly unclear whether or not the chloroplasts of typical dinoflagellates and euglenoids originated in this way from a eukaryotic symbiont: their direct divergence from the ancestral chloroplast cannot be ruled out and indeed has several arguments in its favor. The evidence for and against the view that the chloroplast of the kingdom Chromista was acquired in a single endosymbiotic event is discussed. The possibility that even the chloroplast of Chlorarachnion might have been acquired during the same symbiosis that created the cryptomonad cell, if the symbiont was a primitive alga that had chlorophyll a, b and c as well as phycobilins, is also considered. An alga with such a combination of pigments might have been ancestral to all eukaryote algae. PMID:1292670

  18. A Review of Ideas Concerning Life Origin

    NASA Astrophysics Data System (ADS)

    Gindilis, L. M.

    2014-10-01

    Since the times of Antiquity the and for a long time the idea of self-origination of life was the dominant one. It reappeared again after microorganisms were discovered (XVII century). The possibility of abiogenesis at microbial level was discussed for more than a century. Pateur demonstrated that spontaneous origination of microorganisms in sterile broth was due to those same microorganisms transported by dust particles. Thus proving that every form of life originates from the parental life form. So the question arises: how did the first microorganisms appear on the Earth. There are three possible versions: 1) accidental origination of a viable form; 2) primal organisms were transported to the Earth from outer space; 3) they were formed on the Earth in the process of prebiotic chemical evolution. We discuss the problems of prebiotic evolution from simple monomers up to living cells. An important item of nowadays conceptions of life origination is the hypothesis of the ancient world of RNA as possible precursor of life on Earth. The discovery in carbonaceous chondrites of traces of bacterial life evidences the existence of life in the Solar System even before the formation of the Earth. The idea of life as brought to the Earth out of Cosmos originated under the impression of self-origination hypothesis downfall. It went through several stages (Helmholtz, W. Thompson, XIX century; Arrhenius, early XX century; Hoyle and Wickramasinghe, second half of XX century) and presently evokes constantly growing interest. The panspermia theory does not solve the problem of origination of life, only moves it onto other planets. According to V.A. Mazur, the probability of accidental formation of RNA molecule is negligible not only on the Earth, but in the whole Universe over all the time span of its existence. But it is practically equal to unit in the domain formed at the inflation stage of the evolution of the Universe. A.D.Panov considered panspermia in the Galaxy at the level

  19. An integrative approach to understanding bird origins.

    PubMed

    Xu, Xing; Zhou, Zhonghe; Dudley, Robert; Mackem, Susan; Chuong, Cheng-Ming; Erickson, Gregory M; Varricchio, David J

    2014-12-12

    Recent discoveries of spectacular dinosaur fossils overwhelmingly support the hypothesis that birds are descended from maniraptoran theropod dinosaurs, and furthermore, demonstrate that distinctive bird characteristics such as feathers, flight, endothermic physiology, unique strategies for reproduction and growth, and a novel pulmonary system originated among Mesozoic terrestrial dinosaurs. The transition from ground-living to flight-capable theropod dinosaurs now probably represents one of the best-documented major evolutionary transitions in life history. Recent studies in developmental biology and other disciplines provide additional insights into how bird characteristics originated and evolved. The iconic features of extant birds for the most part evolved in a gradual and stepwise fashion throughout archosaur evolution. However, new data also highlight occasional bursts of morphological novelty at certain stages particularly close to the origin of birds and an unavoidable complex, mosaic evolutionary distribution of major bird characteristics on the theropod tree. Research into bird origins provides a premier example of how paleontological and neontological data can interact to reveal the complexity of major innovations, to answer key evolutionary questions, and to lead to new research directions. A better understanding of bird origins requires multifaceted and integrative approaches, yet fossils necessarily provide the final test of any evolutionary model. PMID:25504729

  20. The precise temporal calibration of dinosaur origins

    NASA Astrophysics Data System (ADS)

    Marsicano, Claudia A.; Irmis, Randall B.; Mancuso, Adriana C.; Mundil, Roland; Chemale, Farid

    2016-01-01

    Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U-Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic-Jurassic boundary.