Science.gov

Sample records for exhibits high-level resistance

  1. The Chlamydia suis genome exhibits high levels of diversity, plasticity and mobile antibiotic resistance: comparative genomics of a recent livestock cohort shows influence of treatment regimes.

    PubMed

    Seth-Smith, Helena M B; Wanninger, Sabrina; Bachmann, Nathan; Marti, Hanna; Qi, Weihong; Donati, Manuela; di Francesco, Antonietta; Polkinghorne, Adam; Borel, Nicole

    2017-03-02

    Chlamydia suis is an endemic pig pathogen, belonging to a fascinating genus of obligate intracellular pathogens. Of particular interest, this is the only chlamydial species to have naturally acquired genes encoding for tetracycline resistance. To date, the distribution and mobility of the Tet-island is not well understood. Our study focused on whole genome sequencing of 29 C. suis isolates from a recent porcine cohort within Switzerland, combined with data from USA tetracycline-resistant isolates. Our findings show that the genome of C. suis is very plastic, with unprecedented diversity, highly affected by recombination and plasmid exchange. A large diversity of isolates circulates within Europe, even within individual Swiss farms, suggesting that C. suis originated around Europe. New World isolates have more restricted diversity and appear to derive from European isolates, indicating that historical strain transfers to the USA have occurred. The architecture of the Tet-island is variable, but the tetA(C) gene is always intact, and recombination has been a major factor in its transmission within C. suis. Selective pressure from tetracycline use within pigs leads to a higher number of Tet-island carrying isolates, which appear to be lost in the absence of such pressure, whereas the loss or gain of the Tet-island from individual strains is not observed. The Tet-island appears to be a recent import into the genome of C. suis, with a possible American origin.

  2. The Chlamydia suis Genome Exhibits High Levels of Diversity, Plasticity, and Mobile Antibiotic Resistance: Comparative Genomics of a Recent Livestock Cohort Shows Influence of Treatment Regimes

    PubMed Central

    Wanninger, Sabrina; Bachmann, Nathan; Marti, Hanna; Qi, Weihong; Donati, Manuela; di Francesco, Antonietta; Polkinghorne, Adam; Borel, Nicole

    2017-01-01

    Chlamydia suis is an endemic pig pathogen, belonging to a fascinating genus of obligate intracellular pathogens. Of particular interest, this is the only chlamydial species to have naturally acquired genes encoding for tetracycline resistance. To date, the distribution and mobility of the Tet-island are not well understood. Our study focused on whole genome sequencing of 29 C. suis isolates from a recent porcine cohort within Switzerland, combined with data from USA tetracycline-resistant isolates. Our findings show that the genome of C. suis is very plastic, with unprecedented diversity, highly affected by recombination and plasmid exchange. A large diversity of isolates circulates within Europe, even within individual Swiss farms, suggesting that C. suis originated around Europe. New World isolates have more restricted diversity and appear to derive from European isolates, indicating that historical strain transfers to the United States have occurred. The architecture of the Tet-island is variable, but the tetA(C) gene is always intact, and recombination has been a major factor in its transmission within C. suis. Selective pressure from tetracycline use within pigs leads to a higher number of Tet-island carrying isolates, which appear to be lost in the absence of such pressure, whereas the loss or gain of the Tet-island from individual strains is not observed. The Tet-island appears to be a recent import into the genome of C. suis, with a possible American origin. PMID:28338777

  3. High-level aminoglycoside resistant enterococci isolated from swine.

    PubMed Central

    Jackson, C. R.; Fedorka-Cray, P. J.; Barrett, J. B.; Ladely, S. R.

    2005-01-01

    Approximately 42% (187/444) of swine enterococci collected between the years 1999 and 2000 exhibited high-level resistance to gentamicin (MIC > or =500 microg/ml), kanamycin (MIC > or =500 microg/ml), or streptomycin (MIC > or =1000 microg/ml). Eight aminoglycoside resistance genes were detected using PCR, most frequently ant(6)-Ia and aac(6')-Ii from Enterococcus faecium. Twenty-four per cent (45/187) of total high-level aminoglycoside-resistant isolates and 26% (4/15) of isolates resistant to high levels of all three antimicrobials were negative for all genes tested. These data suggest that enterococci isolated from swine contain diverse and possibly unidentified aminoglycoside resistance genes. PMID:15816164

  4. High-level aminoglycoside resistant enterococci isolated from swine.

    PubMed

    Jackson, C R; Fedorka-Cray, P J; Barrett, J B; Ladely, S R

    2005-04-01

    Approximately 42% (187/444) of swine enterococci collected between the years 1999 and 2000 exhibited high-level resistance to gentamicin (MIC > or =500 microg/ml), kanamycin (MIC > or =500 microg/ml), or streptomycin (MIC > or =1000 microg/ml). Eight aminoglycoside resistance genes were detected using PCR, most frequently ant(6)-Ia and aac(6')-Ii from Enterococcus faecium. Twenty-four per cent (45/187) of total high-level aminoglycoside-resistant isolates and 26% (4/15) of isolates resistant to high levels of all three antimicrobials were negative for all genes tested. These data suggest that enterococci isolated from swine contain diverse and possibly unidentified aminoglycoside resistance genes.

  5. Development of high-level streptomycin resistance affected by a plasmid in lactic streptococci.

    PubMed

    Sinha, R P

    1986-08-01

    Some lactose-negative (Lac-) mutants of Streptococcus lactis C2 and ML3 exhibited development of very high level streptomycin resistance after incubation with subinhibitory concentrations of the drug for 18 to 22 h. These drug-resistant mutants showed no loss of resistance even after 6 months of subculturing in broth without any drug. The parental Lac+ strains did not show mutation to high-level streptomycin resistance. The Lac+ characteristic of the parental strain was conjugally transferred to Lac- derivatives of C2 and ML3, showing the ability to mutate to high-level resistance. When transconjugants were analyzed for this characteristic, they showed both mutable and nonmutable Lac+ types. The results suggested that genetic information for mutation to high-level streptomycin resistance in lactic streptococci resides on the chromosome, and its expression is affected by a plasmid. The plasmid profiles of strains C2, ML3, C2 Lac-, ML3 Lac-, and two kinds of transconjugants confirmed the presence of a plasmid of approximately 5.5 megadaltons in strains showing no mutation to high-level streptomycin resistance, while strains missing such a plasmid exhibited high-level streptomycin resistance after incubation with subinhibitory concentrations of the drug.

  6. High-level tetracycline resistant Neisseria gonorrhoeae isolated in Portugal.

    PubMed

    Ferreira, E; Louro, D; Gomes, J P; Catry, M A; Pato, M V

    1997-05-01

    The first high-level tetracycline resistance (MIC > or = 16 mg/l) isolates of Neisseria gonorrhoeae (TRNG) were reported in 1990 from patients attending a Sexual Transmitted Disease (STD) Center in Lisbon. The TRNG prevalence was 4% in 1991, 5.3% in 1992 and 10,8% in 1994, exploding to 52.2% in 1995. The tet M determinant was evaluated by PCR. The digests of PCRP using HpaII produced the restriction pattern 2 for all the strains, except one (pattern 3). 78.3% of the TRNG strains were beta-lactamase producers and the 4.5 MDa penicillinase plasmid was the dominant (83%), 90% and 93.3% of the TRNG strains belonged to the auxotype NR and to the serogroup IA, respectively. The IA-8/NR class represented 58.3% of the TRNG isolates, suggesting a clonal spreading.

  7. A New High-Level Gentamicin Resistance Gene, aph(2")-Id, in Enterococcus spp.

    PubMed Central

    Tsai, Shane F.; Zervos, Marcus J.; Clewell, Don B.; Donabedian, Susan M.; Sahm, Daniel F.; Chow, Joseph W.

    1998-01-01

    Enterococcus casseliflavus UC73 is a clinical blood isolate with high-level resistance to gentamicin. DNA preparations from UC73 failed to hybridize with intragenic probes for aac(6′)-Ie-aph(2")-Ia and aph(2")-Ic. A 4-kb fragment from UC73 was cloned and found to confer resistance to gentamicin in Escherichia coli DH5α transformants. Nucleotide sequence analysis revealed the presence of a 906-bp open reading frame whose deduced amino acid sequence had a region with homology to the aminoglycoside-modifying enzyme APH(2")-Ic and to the C-terminal domain of the bifunctional enzyme AAC(6′)-APH(2"). The gene is designated aph(2")-Id, and its observed phosphotransferase activity is designated APH(2")-Id. A PCR-generated intragenic probe hybridized to the genomic DNA from 17 of 118 enterococcal clinical isolates (108 with high-level gentamicin resistance) from five hospitals. All 17 were vancomycin-resistant Enterococcus faecium isolates, and pulsed-field typing revealed three distinct clones. The combination of ampicillin plus either amikacin or neomycin exhibited synergistic killing against E. casseliflavus UC73. Screening and interpretation of high-level aminoglycoside resistance in enterococci may need to be modified to include detection of APH(2")-Id. PMID:9593155

  8. Rapid Induction of High-Level Carbapenem Resistance in Heteroresistant KPC-Producing Klebsiella pneumoniae

    PubMed Central

    Adams-Sapper, Sheila; Nolen, Shantell; Donzelli, Grace Fox; Lal, Mallika; Chen, Kunihiko; Justo da Silva, Livia Helena; Moreira, Beatriz M.

    2015-01-01

    Enterobacteriaceae strains producing the Klebsiella pneumoniae carbapenemase (KPC) have disseminated worldwide, causing an urgent threat to public health. KPC-producing strains often exhibit low-level carbapenem resistance, which may be missed by automated clinical detection systems. In this study, eight Klebsiella pneumoniae strains with heterogeneous resistance to imipenem were used to elucidate the factors leading from imipenem susceptibility to high-level resistance as defined by clinical laboratory testing standards. Time-kill analysis with an inoculum as low as 3 × 106 CFU/ml and concentrations of imipenem 8- and 16-fold higher than the MIC resulted in the initial killing of 99.9% of the population. However, full recovery of the population occurred by 20 h of incubation in the same drug concentrations. Population profiles showed that recovery was mediated by a heteroresistant subpopulation at a frequency of 2 × 10−7 to 3 × 10−6. Samples selected 2 h after exposure to imipenem were as susceptible as the unexposed parental strain and produced the major outer membrane porin OmpK36. However, between 4 to 8 h after exposure, OmpK36 became absent, and the imipenem MIC increased at least 32-fold. Individual colonies isolated from cultures after 20 h of exposure revealed both susceptible and resistant subpopulations. Once induced, however, the high-level imipenem resistance was maintained, and OmpK36 remained unexpressed even without continued carbapenem exposure. This study demonstrates the essential coordination between blaKPC and ompK36 expression mediating high-level imipenem resistance from a population of bacteria that initially exhibits a carbapenem-susceptibility phenotype. PMID:25801565

  9. Superconductive microstrip exhibiting negative differential resistivity

    DOEpatents

    Huebener, R.P.; Gallus, D.E.

    1975-10-28

    A device capable of exhibiting negative differential electrical resistivity over a range of values of current and voltage is formed by vapor- depositing a thin layer of a material capable of exhibiting superconductivity on an insulating substrate, establishing electrical connections at opposite ends of the deposited strip, and cooling the alloy into its superconducting range. The device will exhibit negative differential resistivity when biased in the current- induced resistive state.

  10. High-level gentamicin resistance and vancomycin resistance in clinical isolates of enterococci in a tertiary care hospital in eastern Nepal.

    PubMed

    Nepal, H P; Khanal, B; Acharya, A; Gyawali, N; Jha, P K; Paudel, R

    2012-03-01

    High-level gentamicin resistance and vancomycin resistance in enterococci, a family of important opportunistic pathogens, have emerged as a significant clinical problem over recent years. The present study was conducted to determine the high-level gentamicin and vancomycin resistance among the clinical isolates of enterococci. A total of 110 phenotypically identified enterococcal isolates were subjected to determination of high-level gentamicin resistance (by disk diffusion and agar dilution methods) and vancomycin resistance (by agar screening and agar dilution methods). About 36% of the isolates were found to have high-level gentamicin resistance, which indicates that gentamicin no longer remains an appropriate choice for inclusion in combination therapy with cell wall-active agents. Ten percent isolates exhibited resisance to vancomycin during screening. However, agar dilution confirmed that the isolates did not have resistance to vancomycin but had reduced susceptibility to it, which indicates their impending emergence of resistance to vancomycin.

  11. A high level of transgenic viral small RNA is associated with broad potyvirus resistance in cucurbits.

    PubMed

    Leibman, Diana; Wolf, Dalia; Saharan, Vinod; Zelcer, Aaron; Arazi, Tzahi; Yoel, Shiboleth; Gaba, Victor; Gal-On, Amit

    2011-10-01

    Gene-silencing has been used to develop resistance against many plant viruses but little is known about the transgenic small-interfering RNA (t-siRNA) that confers this resistance. Transgenic cucumber and melon lines harboring a hairpin construct of the Zucchini yellow mosaic potyvirus (ZYMV) HC-Pro gene accumulated different levels of t-siRNA (6 to 44% of total siRNA) and exhibited resistance to systemic ZYMV infection. Resistance to Watermelon mosaic potyvirus and Papaya ring spot potyvirus-W was also observed in a cucumber line that accumulated high levels of t-siRNA (44% of total siRNA) and displayed significantly increased levels of RNA-dependent RNA (RDR)1 and Argonaute 1, as compared with the other transgenic and nontransformed plants. The majority of the t-siRNA sequences were 21 to 22 nucleotides in length and sense strand biased. The t-siRNA were not uniformly distributed throughout the transgene but concentrated in "hot spots" in a pattern resembling that of the viral siRNA peaks observed in ZYMV-infected cucumber and melon. Mutations in ZYMV at the loci associated with the siRNA peaks did not break this resistance, indicating that hot spot t-siRNA may not be essential for resistance. This study shows that resistance based on gene-silencing can be effective against related viruses and is probably correlated with t-siRNA accumulation and increased expression of RDR1.

  12. Blunted cardiac stress reactors exhibit relatively high levels of behavioural impulsivity.

    PubMed

    Bibbey, Adam; Ginty, Annie T; Brindle, Ryan C; Phillips, Anna C; Carroll, Douglas

    2016-05-15

    Blunted physiological reactions to acute psychological stress are associated with a range of adverse health and behavioural outcomes. This study examined whether extreme stress reactors differ in their behavioural impulsivity. Individuals showing blunted (N=23) and exaggerated (N=23) cardiovascular reactions to stress were selected by screening a healthy student population (N=276). Behavioural impulsivity was measured via inhibitory control and motor impulsivity tasks. Blunted reactors exhibited greater impulsivity than exaggerated reactors on both stop-signal, F(1,41)=4.99, p=0.03, ηp(2)=0.108, and circle drawing, F(1,43)=4.00, p=0.05, η p(2)=0.085, tasks. Individuals showing blunted cardiovascular stress reactions are characterized by greater impulsivity which may contribute to their increased susceptibility to outcomes such as obesity and addiction.

  13. PBP 4 Mediates High-Level Resistance to New-Generation Cephalosporins in Staphylococcus aureus

    PubMed Central

    Chan, Liana C.; Gilbert, Aubre; Basuino, Li; da Costa, Thaina M.; Hamilton, Stephanie M.; dos Santos, Katia R.; Chambers, Henry F.

    2016-01-01

    Staphylococcus aureus is an important cause of both hospital- and community-associated methicillin-resistant S. aureus (MRSA) infections worldwide. β-Lactam antibiotics are the drugs of choice to treat S. aureus infections, but resistance to these and other antibiotics make treatment problematic. High-level β-lactam resistance of S. aureus has always been attributed to the horizontally acquired penicillin binding protein 2a (PBP 2a) encoded by the mecA gene. Here, we show that S. aureus can also express high-level resistance to β-lactams, including new-generation broad-spectrum cephalosporins that are active against methicillin-resistant strains, through an uncanonical core genome-encoded penicillin binding protein, PBP 4, a nonessential enzyme previously considered not to be important for staphylococcal β-lactam resistance. Our results show that PBP 4 can mediate high-level resistance to β-lactams. PMID:27067335

  14. OCCURRENCE OF HIGH-LEVEL AMINOGLYCOSIDE RESISTANCE IN ENVIRONMENTAL ISOLATES OF ENTEROCOCCI

    EPA Science Inventory

    High-level resistance fo aminoglycosides was observed in environmental isolates of enterococci. Various aquatic habitats, including agricultural runoff, creeks, rivers, wastewater, and wells, were analyzed. Strains of Enterococcus faecalis, e.faecium, E. gallinarum, and other Ent...

  15. Enterococci from Bangkok, Thailand, with high-level resistance to currently available aminoglycosides.

    PubMed Central

    Murray, B E; Tsao, J; Panida, J

    1983-01-01

    Enterococcal endocarditis is usually treated with a combination of a penicillin and an aminoglycoside. Recent reports have documented the emergence of enterococci in France with high-level resistance to gentamicin, tobramycin, and kanamycin and the emergence of strains in Houston, Tex. with high-level resistance to all of these drugs and streptomycin. In this study, we examined strains from a geographic area where newer aminoglycosides have been less commonly used. Of 125 distinct patient isolates, 18 (14%) were resistant to greater than 2,000 micrograms of gentamicin and most other aminoglycosides per ml. Four of these strains transferred gentamicin resistance to a laboratory recipient. One strain, chosen for further study, was resistant to synergism between penicillin and gentamicin, tobramycin, kanamycin, streptomycin, and amikacin and demonstrated the following enzymatic activities: 3'- and 2"-aminoglycoside phosphotransferases, 6'-aminoglycoside acetyltransferase, and adenylylation of streptomycin. Optimal therapy for endocarditis caused by such highly resistant strains is currently unknown. PMID:6614889

  16. Comparative genome analysis of high-level penicillin resistance in Streptococcus pneumoniae.

    PubMed

    Tait-Kamradt, Amelia G; Cronan, Melissa; Dougherty, Thomas J

    2009-06-01

    Streptococcus pneumoniae strains with very high levels of penicillin resistance (minimum inhibitory concentration [MIC] >or=8 microg/ml) emerged in the 1990 s. Previous studies have traced the changes in penicillin binding proteins (PBP) that result in decreased penicillin susceptibility, and the role of several PBP genes in high-level resistance. In the present study, we investigated the changes that occurred at the two highest levels of penicillin resistance using NimbleGen's Comparative Genome Sequencing (CGS) technology. DNA from a highly resistant (Pen MIC 16 microg/ml) pneumococcus was used to serially transform the R6 strain to high-level resistance. Four distinct levels of penicillin resistance above the susceptible R6 strain (MIC 0.016 microg/ml) were identified. Using CGS technology, the entire genome sequences of the two highest levels of resistant transformants were examined for changes associated with the resistance phenotypes. At the third level of resistance, changes in PBPs 1a, 2b, and 2x were found, very similar to previous reports. At the fourth resistance level, two additional changes were observed in the R6 transformants. More changes were observed in PBP2x, as well as in peptidoglycan GlcNAc deacetylase (pdgA), which had a missense mutation in the coding region. Genetic transformation with polymerase chain reaction (PCR) products generated from the high-level resistant parent containing either the additional PBP2x or mutant pdgA gene did not increase the MIC of the third-level transformant. Only when both PCR products were simultaneously transformed into the third-level transformant did colonies emerge that were at the highest level of resistance (16-32 microg/ml), equivalent to the highly resistant parent strain. This is the first instance of the involvement of a variant pdgA gene in penicillin resistance. It is also clear from these experiments and the literature that there are multiple paths to the pneumococcus achieving high-level

  17. High Levels of Expression of P-glycoprotein/Multidrug Resistance Protein Result in Resistance to Vintafolide.

    PubMed

    Guertin, Amy D; O'Neil, Jennifer; Stoeck, Alexander; Reddy, Joseph A; Cristescu, Razvan; Haines, Brian B; Hinton, Marlene C; Dorton, Ryan; Bloomfield, Alicia; Nelson, Melissa; Vetzel, Marilynn; Lejnine, Serguei; Nebozhyn, Michael; Zhang, Theresa; Loboda, Andrey; Picard, Kristen L; Schmidt, Emmett V; Dussault, Isabelle; Leamon, Christopher P

    2016-08-01

    Targeting surface receptors overexpressed on cancer cells is one way to specifically treat cancer versus normal cells. Vintafolide (EC145), which consists of folate linked to a cytotoxic small molecule, desacetylvinblastine hydrazide (DAVLBH), takes advantage of the overexpression of folate receptor (FR) on cancer cells. Once bound to FR, vintafolide enters the cell by endocytosis, and the reducing environment of the endosome cleaves the linker, releasing DAVLBH to destabilize microtubules. Vintafolide has shown efficacy and improved tolerability compared with DAVLBH in FR-positive preclinical models. As the first FR-targeting drug to reach the clinic, vintafolide has achieved favorable responses in phase II clinical trials in FR-positive ovarian and lung cancer. However, some FR-positive patients in these clinical trials do not respond to vintafolide. We sought to identify potential biomarkers of resistance to aid in the future development of this and other FR-targeting drugs. Here, we confirm that high P-glycoprotein (P-gp) expression was the strongest predictor of resistance to DAVLBH in a panel of 359 cancer cell lines. Furthermore, targeted delivery of DAVLBH via the FR, as in vintafolide, fails to overcome P-gp-mediated efflux of DAVLBH in both in vitro and in vivo preclinical models. Therefore, we suggest that patients whose tumors express high levels of P-gp be excluded from future clinical trials for vintafolide as well as other FR-targeted therapeutics bearing a P-gp substrate. Mol Cancer Ther; 15(8); 1998-2008. ©2016 AACR.

  18. Molecular Characterization of High-Level Mupirocin Resistance in Staphylococcus pseudintermedius

    PubMed Central

    Pérez-Roth, Eduardo; Pintarić, Selma; Šeol Martinec, Branka

    2013-01-01

    The genetic analysis of high-level mupirocin resistance (Hi-Mupr) in a Staphylococcus pseudintermedius isolate from a dog is presented. The Hi-Mupr ileS2 gene flanked by a novel rearrangement of directly repeated insertion sequence IS257 elements was located, together with the aminoglycoside resistance aacA-aphD determinant, on a conjugative plasmid related to the pSK41/pGO1 family plasmids. PMID:23269741

  19. High Levels of Resistance in the Common Bed Bug, Cimex lectularius (Hemiptera: Cimicidae), to Neonicotinoid Insecticides.

    PubMed

    Romero, Alvaro; Anderson, Troy D

    2016-05-01

    The rapid increase of bed bug populations resistant to pyrethroids demands the development of novel control tactics. Products combining pyrethroids and neonicotinoids have become very popular for bed bug control in the United States, but there are concerns about evolution of resistance to these compounds. Laboratory assays were used to measure the toxicity of topical applications of four neonicotinoids to a susceptible population and three pyrethroid-resistant populations. Activity of esterases, glutathione S-transferases, and cytochrome P450s of all strains was also evaluated. High levels of resistance to four neonicotinoids, acetamiprid, imidacloprid, dinotefuran, and thiamethoxam, relative to the susceptible Fort Dix population, were detected in populations collected from human dwellings in Cincinnati and Michigan. Because activity of detoxifying enzymes was increased in these two populations, our results suggest that these enzymes have some involvement in neonicotinoid resistance, but other resistance mechanisms might be involved as well. Detection of high levels of resistance to neonicotinoids further limits the options for chemical control of bed bugs.

  20. High-level aminoglycoside resistance and virulence characteristics among Enterococci isolated from recreational beaches in Malaysia.

    PubMed

    Dada, Ayokunle Christopher; Ahmad, Asmat; Usup, Gires; Heng, Lee Yook; Hamid, Rahimi

    2013-09-01

    We report the first study on the occurrence of high-level aminoglycoside-resistant (HLAR) Enterococci in coastal bathing waters and beach sand in Malaysia. None of the encountered isolates were resistant to high levels of gentamicin (500 μg/mL). However, high-level resistance to kanamycin (2,000 μg/mL) was observed in 14.2 % of tested isolates, the highest proportions observed being among beach sand isolates. High-level resistance to kanamycin was higher among Enterococcus faecalis and Enterococcus faecium than Enterococcus spp. Chi-square analysis showed no significant association between responses to tested antibiotics and the species allocation or source of isolation of all tested Enterococci. The species classification of encountered Enterococci resistance to vancomycin was highest among Enterococcus spp. (5.89 %) followed by E. faecium (4.785) and least among E. faecalis. A total of 160 isolates were also tested for virulence characteristics. On the whole, caseinase production was profoundly highest (15.01 %) while the least prevalent virulence characteristic observed among tested beach Enterococci was haemolysis of rabbit blood (3.65 %). A strong association was observed between the source of isolation and responses for each of caseinase (C = 0.47, V = 0.53) and slime (C = 0.50, V = 0.58) assays. Analysis of obtained spearman's coefficient showed a strong correlation between caseinase and each of the slime production (p = 0.04), gelatinase (p = 0.0035) and haemolytic activity on horse blood (p = 0.004), respectively. Suggestively, these are the main virulent characteristics of the studied beach Enterococci. Our findings suggest that recreational beaches may contribute to the dissemination of Enterococci with HLAR and virulence characteristics.

  1. Antimicrobial susceptibility and mechanisms of high-level macrolide resistance in clinical isolates of Moraxella nonliquefaciens.

    PubMed

    Nonaka, Shotaro; Matsuzaki, Kosuke; Kazama, Tomoya; Nishiyama, Hiroyuki; Ida, Yoko; Koyano, Saho; Sonobe, Kazunari; Okamura, Noboru; Saito, Ryoichi

    2014-02-01

    We investigated antimicrobial susceptibility and the molecular mechanism involved in conferring high-level macrolide resistance in 47 clinical isolates of Moraxella nonliquefaciens from Japan. Antimicrobial susceptibility was determined using Etest and agar dilution methods. Thirty-two erythromycin-non-susceptible strains were evaluated for the possibility of clonal spreading, using PFGE. To analyse the mechanism related to macrolide resistance, mutations in the 23S rRNA gene and the ribosomal proteins, and the presence of methylase genes were investigated by PCR and sequencing. The efflux system was examined using appropriate inhibitors. Penicillin, ampicillin, amoxicillin, cefixime, levofloxacin and antimicrobials containing β-lactamase inhibitors showed strong activity against 47 M. nonliquefaciens isolates. Thirty-two (68.1 %) of the 47 isolates showed high-level MICs to macrolides (MIC ≥128 mg l(-1)) and shared the A2058T mutation in the 23S rRNA gene. The geometric mean MIC to macrolides of A2058T-mutated strains was significantly higher than that of WT strains (P<0.0001). Thirty-two isolates with high-level macrolide MICs clustered into 30 patterns on the basis of the PFGE dendrogram, indicating that the macrolide-resistant strains were not clonal. In contrast, no common mutations of the ribosomal proteins or methylase genes, or overproduction of the efflux system were observed in A2058T-mutated strains. Moreover, of the 47 M. nonliquefaciens strains, 43 (91.5 %) were bro-1 and 4 (8.5 %) were bro-2 positive. Our results suggest that most M. nonliquefaciens clinical isolates show high-level macrolide resistance conferred by the A2058T mutation in the 23S rRNA gene. This study represents the first characterization of M. nonliquefaciens.

  2. Assessment of pheromone response in biofilm forming clinical isolates of high level gentamicin resistant Enterococcus faecalis.

    PubMed

    Jayanthi, S; Ananthasubramanian, M; Appalaraju, B

    2008-01-01

    Twenty five clinical isolates of high level gentamicin resistant Enterococcus faecalis were tested for their biofilm formation and pheromone responsiveness. The biofilm assay was carried out using microtiter plate method. Two isolates out of the 25 (8%) were high biofilm formers and 19 (76%) and four (16%) isolates were moderate and weak biofilm formers respectively. All the isolates responded to pheromones of E. faecalis FA2-2 strain. On addition of pheromone producing E. faecalis FA2-2 strain to these isolates, seven of 19 (37%) moderate biofilm formers developed into high biofilm formers. Similarly one of the 4 (25%) weak biofilm formers developed into high level biofilm former. Twelve (48%) of the 25 isolates were transconjugated by cross streak method using gentamicin as selective marker. This proves that the genetic factor for gentamicin resistance is present in the pheromone responsive plasmid. Among these twelve transaconjugants, seven isolates and one isolate were high biofilm formers on addition of E. faecalis FA2-2 and prior to its addition respectively. Out of the total 25 isolates, eight transconjugants for gentamicin resistance could turn to high biofilm formers on addition of the pheromone producing strain. All the isolates were resistant to more than two antibiotics tested. All the isolates were sensitive to vancomycin. The results indicate the significance of this nosocomial pathogen in biofilm formation and the role of pheromone responding clinical isolates of E. faecalis in spread of multidrug resistance genes.

  3. High level resistance against rhizomania disease by simultaneously integrating two distinct defense mechanisms.

    PubMed

    Pavli, Ourania I; Tampakaki, Anastasia P; Skaracis, George N

    2012-01-01

    With the aim of achieving durable resistance against rhizomania disease of sugar beet, the employment of different sources of resistance to Beet necrotic yellow vein virus was pursued. To this purpose, Nicotiana benthamiana transgenic plants that simultaneously produce dsRNA originating from a conserved region of the BNYVV replicase gene and the HrpZ(Psph) protein in a secreted form (SP/HrpZ(Psph)) were produced. The integration and expression of both transgenes as well as proper production of the harpin protein were verified in all primary transformants and selfed progeny (T1, T2). Transgenic resistance was assessed by BNYVV-challenge inoculation on T2 progeny by scoring disease symptoms and DAS-ELISA at 20 and 30 dpi. Transgenic lines possessing single transformation events for both transgenes as well as wild type plants were included in inoculation experiments. Transgenic plants were highly resistant to virus infection, whereas in some cases immunity was achieved. In all cases, the resistant phenotype of transgenic plants carrying both transgenes was superior in comparison with the ones carrying a single transgene. Collectively, our findings demonstrate, for a first time, that the combination of two entirely different resistance mechanisms provide high level resistance or even immunity against the virus. Such a novel approach is anticipated to prevent a rapid virus adaptation that could potentially lead to the emergence of isolates with resistance breaking properties.

  4. PBP2a Mutations Causing High-Level Ceftaroline Resistance in Clinical Methicillin-Resistant Staphylococcus aureus Isolates

    PubMed Central

    Long, S. Wesley; Olsen, Randall J.; Mehta, Shrenik C.; Palzkill, Timothy; Cernoch, Patricia L.; Perez, Katherine K.; Musick, William L.; Rosato, Adriana E.

    2014-01-01

    Ceftaroline is the first member of a novel class of cephalosporins approved for use in the United States. Although prior studies have identified eight ceftaroline-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolates in Europe and Asia with MICs ranging from 4 to 8 mg/liter, high-level resistance to ceftaroline (>32 mg/liter) has not been described in MRSA strains isolated in the United States. We isolated a ceftaroline-resistant (MIC > 32 mg/liter) MRSA strain from the blood of a cystic fibrosis patient and five MRSA strains from the respiratory tract of this patient. Whole-genome sequencing identified two amino acid-altering mutations uniquely present in the ceftaroline-binding pocket of the transpeptidase region of penicillin-binding protein 2a (PBP2a) in ceftaroline-resistant isolates. Biochemical analyses and the study of isogenic mutant strains confirmed that these changes caused ceftaroline resistance. Thus, we identified the molecular mechanism of ceftaroline resistance in the first MRSA strain with high-level ceftaroline resistance isolated in the United States. PMID:25155594

  5. High-Level Vancomycin-Resistant Staphylococcus aureus Isolates Associated with a Polymicrobial Biofilm▿

    PubMed Central

    Weigel, Linda M.; Donlan, Rodney M.; Shin, Dong Hyeon; Jensen, Bette; Clark, Nancye C.; McDougal, Linda K.; Zhu, Wenming; Musser, Kimberlee A.; Thompson, Jill; Kohlerschmidt, Donna; Dumas, Nellie; Limberger, Ronald J.; Patel, Jean B.

    2007-01-01

    Glycopeptides such as vancomycin are the treatment of choice for infections due to methicillin-resistant Staphylococcus aureus. This study describes the identification of high-level vancomycin-resistant S. aureus (VRSA) isolates in a polymicrobial biofilm within an indwelling nephrostomy tube in a patient in New York. S. aureus, Enterococcus faecalis, Enterococcus faecium, Micrococcus species, Morganella morganii, and Pseudomonas aeruginosa were isolated from the biofilm. For VRSA isolates, vancomycin MICs ranged from 32 to >128 μg/ml. VRSA isolates were also resistant to aminoglycosides, fluoroquinolones, macrolides, penicillin, and tetracycline but remained susceptible to chloramphenicol, linezolid, rifampin, and trimethoprim-sulfamethoxazole. The vanA gene was localized to a plasmid of ∼100 kb in VRSA and E. faecium isolates from the biofilm. Plasmid analysis revealed that the VRSA isolate acquired the 100-kb E. faecium plasmid, which was then maintained without integration into the MRSA plasmid. The tetracycline resistance genes tet(U) and tet(S), not previously detected in S. aureus isolates, were identified in the VRSA isolates. Additional resistance elements in the VRSA isolate included a multiresistance gene cluster, ermB-aadE-sat4-aphA-3, msrA (macrolide efflux), and the bifunctional aminoglycoside resistance gene aac(6′)-aph(2")-Ia. Multiple combinations of resistance genes among the various isolates of staphylococci and enterococci, including vanA, tet(S), and tet(U), illustrate the dynamic nature of gene acquisition and loss within and between bacterial species throughout the course of infection. The potential for interspecies transfer of antimicrobial resistance genes, including resistance to vancomycin, may be enhanced by the microenvironment of a biofilm. PMID:17074796

  6. High-level amikacin resistance in Escherichia coli due to phosphorylation and impaired aminoglycoside uptake.

    PubMed Central

    Perlin, M H; Lerner, S A

    1986-01-01

    Plasmid pMP1-1 in Escherichia coli L-0 encodes aminoglycoside (AG) 3'-phosphotransferase II [APH(3')-II]. This enzyme modifies and confers high-level resistance to kanamycin. Although amikacin is a substrate for APH(3')-II, strain L-0(pMP1-1) is susceptible to amikacin. Plasmid pMP1-2 is a spontaneous mutant of pMP1-1 which determines increased APH(3')-II activity for amikacin, apparently as a result of an increase in the copy number of the plasmid. From amikacin-susceptible, gentamicin-susceptible transformants and transconjugants that bear the APH(3')-II gene on plasmid pMP1-1 or pMP1-2 or cloned into multicopy plasmid pBR322, we selected spontaneous mutants at concentrations of amikacin or gentamicin that were two to four times higher than the MICs of these antibiotics. In each case, whether they were selected by using amikacin or gentamicin, the mutants exhibited modest (two- to eightfold) increases in the MIC of gentamicin and major (64- to 128-fold) increases in the MIC of amikacin. Using these laboratory strains of E. coli, we examined the effects on AG susceptibility of the interaction of AG-modifying enzyme activity and generalized AG uptake. Increasing the level of activity of an AG phosphotransferase in these strains lowered their susceptibility to AGs which were substrates for which the enzyme had low Kms. However, an increase in AG-modifying activity alone did not result in large increases in the MICs for poor substrates of the enzyme. In strains which lacked AG-modifying enzymes, a decrease in the rate of AG uptake increased the MICs modestly for a broad spectrum of AGs. When a strain bore the phosphotransferase, a decrease in generalized AG uptake could raise the MIC further, not only for low-Km substrates, but even for AG substrates for which the enzyme had high Kms. Thus, increased modifying activity, together with a diminished rate of uptake, could produce even higher MICs for poor AG substrates. PMID:2424366

  7. High level methicillin resistance correlates with reduced Staphylococcus aureus endothelial cell damage.

    PubMed

    Seidl, Kati; Leemann, Michèle; Palheiros Marques, Miguel; Rachmühl, Carole; Leimer, Nadja; Andreoni, Federica; Achermann, Yvonne; Zinkernagel, Annelies S

    2017-01-01

    There has been controversy about the intrinsic virulence of methicillin-resistant Staphylococcus aureus (MRSA) as compared to methicillin-susceptible S. aureus (MSSA). To address this discrepancy, the intrinsic virulence of 42 MRSA and 40 MSSA clinical isolates was assessed by testing endothelial cell (EC) damage, a surrogate marker for virulence in blood stream infections. Since these clinical isolates represent a heterogeneous group, well characterized S. aureus laboratory strains with SCCmec loss- and gain-of-function mutations were used in addition. The clinical MRSA isolates carrying typical hospital acquired SCCmec types (I, II or III) induced significantly less damage (47.8%) as compared to isolates with other SCCmec types (62.3%, p=0.03) and MSSA isolates (64.2%, p<0.01). There was a strong inverse correlation between high-level oxacillin resistance and low EC damage induction (R(2)=0.4464, p<0.001). High-level oxacillin resistant strains (MIC >32μ/ml) grew significantly slower as compared to isolates with low-level resistance (p=0.047). The level of EC damage positively correlated with α- and δ-toxin production (p<0.0001 and p<0.05, respectively) but not with β-toxin production. Invasive MRSA isolates (n=21, 56.3%) were significantly less cytotoxic as compared to invasive MSSA isolates (n=20, 68.0%, p<0.05). There was no difference between EC damage induced by superficial versus invasive isolates in either MRSA or MSSA strains. Our data suggest that the intrinsic virulence of MRSA is similar or even reduced as compared to MSSA strains but is linked to the level of methicillin resistance.

  8. Inheritance of high levels of resistance to common bacterial blight caused by Xanthomonas Axonopodis pv. Phaseoli in common bean (Phaseolus vulgaris L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Common bacterial blight caused by the pathogen Xanthomonas axonopodis pv. phaseoli (Xap) is an important biotic factor limiting common bean (Phaseolus vulgaris L.) production. A few interspecific bean breeding lines such as VAX 6 exhibit a high level of resistance to a wide range of Xap strains repr...

  9. In vitro antibacterial activity of seven Indian spices against high level gentamicin resistant strains of enterococci

    PubMed Central

    Bipin, Chapagain; Chitra, Pai (Bhat); Minakshi, Bhattacharjee

    2015-01-01

    Introduction The aim of the study was to explore the in vitro antibacterial activity of seven ethanolic extracts of spices against high level gentamicin resistant (HLGR) enterococci isolated from human clinical samples. Material and methods Two hundred and fifteen enterococcal strains were isolated from clinical samples. High level gentamicin resistance in ethanolic extracts of cumin (Cuminum cyminum), cinnamon (Cinnamomum zeylanicum), ginger (Zingiber officinale), fenugreek (Trigonella foenum-graecum), cloves (Syzygium aromaticum), cardamom (Elettaria cardamomum Maton) and black pepper (Piper nigrum) were prepared using Soxhlet apparatus. The antibacterial effect of the extracts was studied using the well diffusion method. Statistical analysis was carried out by χ2 test using SPSS 17 software. Results Only cinnamon and ginger were found to have activity against all the isolates, whereas cumin and cloves had a variable effect on the strains. Fenugreek, black pepper and cardamom did not show any effect on the isolates. The zone diameter of inhibition obtained for cinnamon, ginger, cloves and cumin was in the range 31–34 mm, 27–30 mm, 25–26 mm and 19–20 mm respectively. Conclusions Cinnamomum zeylanicum and Z. officinale showed the maximum antibacterial activity against the enterococcal isolates followed by S. aromaticum and C. cyminum. The findings of the study show that spices used in the study can contribute to the development of potential antimicrobial agents for inclusion in the anti-enterococcal treatment regimen. PMID:26322099

  10. High-level fluoroquinolone resistance in Streptococcus pneumoniae requires mutations in parC and gyrA.

    PubMed Central

    Janoir, C; Zeller, V; Kitzis, M D; Moreau, N J; Gutmann, L

    1996-01-01

    The mechanism of high-level fluoroquinolone resistance was studied in strains of Streptococcus pneumoniae, either selected in vitro or isolated from clinical samples. By using DNA from these high-level-resistant strains, low-level-resistant transformants (MIC of pefloxacin, > or = 32 micrograms/ml; MIC of ciprofloxacin, 4 micrograms/ml; MIC of sparfloxacin, 0.50 micrograms/ml) were obtained at high frequencies (ca.10(-2)), while high-level-resistant transformants (MIC of pefloxacin, > or = 64 micrograms/ml; MIC of ciprofloxacin, 16 to 64 micrograms/ml; MIC of sparfloxacin, > or = 8 micrograms/ml) were obtained only at low frequencies (ca.10(-4)). This suggested that mutations in at least two unlinked genes were necessary to obtain high-level resistance. Low-level resistance was associated with ParC mutations (change from Ser to Tyr at position 79 [Ser79Tyr], Ser79Phe, or Asp83Gly). ParC mutations were associated, in high-level-resistant strains and transformants, with alterations in the quinolone resistance-determining region of GyrA (Ser84Tyr, Ser84Phe, and/or Glu88Lys). Low-level resistance was shown to be necessary for expression of the gyrA mutations. No mutation in the region corresponding to the quinolone resistance-determining region of GyrB and no alteration of drug accumulation were found. PMID:9124836

  11. Molecular Correlates of High-Level Antifolate Resistance in Rwandan Children with Plasmodium falciparum Malaria▿

    PubMed Central

    Karema, Corine; Imwong, Mallika; Fanello, Caterina I.; Stepniewska, Kasia; Uwimana, Aline; Nakeesathit, Supatchara; Dondorp, Arjen; Day, Nicholas P.; White, Nicholas J.

    2010-01-01

    Antifolate drugs have an important role in the treatment of malaria. Polymorphisms in the genes encoding the dihydrofolate reductase and dihydropteroate synthetase enzymes cause resistance to the antifol and sulfa drugs, respectively. Rwanda has the highest levels of antimalarial drug resistance in Africa. We correlated the efficacy of chlorproguanil-dapsone plus artesunate (CPG-DDS+A) and amodiaquine plus sulfadoxine-pyrimethamine (AQ+SP) in children with uncomplicated malaria caused by Plasmodium falciparum parasites with pfdhfr and pfdhps mutations, which are known to confer reduced drug susceptibility, in two areas of Rwanda. In the eastern province, where the cure rates were low, over 75% of isolates had three or more pfdhfr mutations and two or three pfdhps mutations and 11% had the pfdhfr 164-Leu polymorphism. In the western province, where the cure rates were significantly higher (P < 0.001), the prevalence of multiple resistance mutations was lower and the pfdhfr I164L polymorphism was not found. The risk of treatment failure following the administration of AQ+SP more than doubled for each additional pfdhfr resistance mutation (odds ratio [OR] = 2.4; 95% confidence interval [CI] = 1.01 to 5.55; P = 0.048) and each pfdhps mutation (OR = 2.1; 95% CI = 1.21 to 3.54; P = 0.008). The risk of failure following CPG-DDS+A treatment was 2.2 times higher (95% CI = 1.34 to 3.7) for each additional pfdhfr mutation, whereas there was no association with mutations in the pfdhps gene (P = 0.13). The pfdhfr 164-Leu polymorphism is prevalent in eastern Rwanda. Antimalarial treatments with currently available antifol-sulfa combinations are no longer effective in Rwanda because of high-level resistance. PMID:19841150

  12. Genotypic and phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clones with high-level mupirocin resistance.

    PubMed

    González-Domínguez, María; Seral, Cristina; Potel, Carmen; Sáenz, Yolanda; Álvarez, Maximiliano; Torres, Carmen; Castillo, Francisco Javier

    2016-06-01

    A high proportion of methicillin-resistant Staphylococcus aureus isolates recovered in one year period showed high-level mupirocin-resistance (HLMUPR-MRSA) in our environment (27.2%). HLMUPR-MRSA isolates were mainly collected from skin and soft tissue samples, and diabetes was the main related comorbidity condition. These isolates were more frequently found in vascular surgery. HLMUPR-MRSA was more resistant to aminoglycosides than mupirocin-susceptible MRSA, linked to the presence of bifunctional and/or nucleotidyltransferase enzymes with/without macrolide resistance associated with the msr(A) gene. Most of HLMUPR-MRSA isolates belonged to ST125/t067. Nine IS257-ileS2 amplification patterns (p3 was the most frequent) were observed in HLMUPR-MRSA isolates, suggesting the presence of several mupirocin-resistance-carrying plasmids in our environment and promoting the emergence of mupirocin resistance. The presence of the same IS257-ileS2 amplification pattern p3 in 65% of HLMUPR-MRSA, all of them ST125/t067, suggests a clonal spread in our hospital and community environment which could explain the high prevalence of HLMUPR-MRSA during the study period. An outbreak situation or an increase in mupirocin consumption was not observed.

  13. High Level Aminoglycoside Resistance and Distribution of Aminoglycoside Resistant Genes among Clinical Isolates of Enterococcus Species in Chennai, India

    PubMed Central

    Padmasini, Elango; Padmaraj, R.; Ramesh, S. Srivani

    2014-01-01

    Enterococci are nosocomial pathogen with multiple-drug resistance by intrinsic and extrinsic mechanisms. Aminoglycosides along with cell wall inhibitors are given clinically for treating enterococcal infections. 178 enterococcal isolates were analyzed in this study. E. faecalis is identified to be the predominant Enterococcus species, along with E. faecium, E. avium, E. hirae, E. durans, E. dispar and E. gallinarum. High level aminoglycoside resistance (HLAR) by MIC for gentamicin (GM), streptomycin (SM) and both (GM + SM) antibiotics was found to be 42.7%, 29.8%, and 21.9%, respectively. Detection of aminoglycoside modifying enzyme encoding genes (AME) in enterococci was identified by multiplex PCR for aac(6′)-Ie-aph(2′′)-Ia; aph(2′′)-Ib; aph(2′′)-Ic; aph(2′′)-Id and aph(3′)-IIIa genes. 38.2% isolates carried aac(6′)-Ie-aph(2′′)-Ia gene and 40.4% isolates carried aph(3′)-IIIa gene. aph(2′′)-Ib; aph(2′′)-Ic; aph(2′′)-Id were not detected among our study isolates. aac(6′)-Ie-aph(2′′)-Ia and aph(3′)-IIIa genes were also observed in HLAR E. durans, E. avium, E. hirae, and E. gallinarum isolates. This indicates that high level aminoglycoside resistance genes are widely disseminated among isolates of enterococci from Chennai. PMID:24672306

  14. Genetic basis of high level aminoglycoside resistance in Acinetobacter baumannii from Beijing, China

    PubMed Central

    Nie, Lu; Lv, Yuemeng; Yuan, Min; Hu, Xinxin; Nie, Tongying; Yang, Xinyi; Li, Guoqing; Pang, Jing; Zhang, Jingpu; Li, Congran; Wang, Xiukun; You, Xuefu

    2014-01-01

    The objective of this study was to investigate the genetic basis of high level aminoglycoside resistance in Acinetobacter baumannii clinical isolates from Beijing, China. 173 A. baumannii clinical isolates from hospitals in Beijing from 2006 to 2009 were first subjected to high level aminoglycoside resistance (HLAR, MIC to gentamicin and amikacin>512 µg/mL) phenotype selection by broth microdilution method. The strains were then subjected to genetic basis analysis by PCR detection of the aminoglycoside modifying enzyme genes (aac(3)-I, aac(3)-IIc, aac(6′)-Ib, aac(6′)-II, aph(4)-Ia, aph(3′)-I, aph(3′)-IIb, aph(3′)-IIIa, aph(3′)-VIa, aph(2″)-Ib, aph(2″)-Ic, aph(2″)-Id, ant(2″)-Ia, ant(3″)-I and ant(4′)-Ia) and the 16S rRNA methylase genes (armA, rmtB and rmtC). Correlation analysis between the presence of aminoglycoside resistance gene and HLAR phenotype were performed by SPSS. Totally 102 (58.96%) HLAR isolates were selected. The HLAR rates for year 2006, 2007, 2008 and 2009 were 52.63%, 65.22%, 51.11% and 70.83%, respectively. Five modifying enzyme genes (aac(3)-I, detection rate of 65.69%; aac(6′)-Ib, detection rate of 45.10%; aph(3′)-I, detection rate of 47.06%; aph(3′)-IIb, detection rate of 0.98%; ant(3″)-I, detection rate of 95.10%) and one methylase gene (armA, detection rate of 98.04%) were detected in the 102 A. baumannii with aac(3)-I+aac(6′)-Ib+ant(3″)-I+armA (detection rate of 25.49%), aac(3)-I+aph(3′)-I+ant(3″)-I+armA (detection rate of 21.57%) and ant(3″)-I+armA (detection rate of 12.75%) being the most prevalent gene profiles. The values of chi-square tests showed correlation of armA, ant(3″)-I, aac(3)-I, aph(3′)-I and aac(6′)-Ib with HLAR. armA had significant correlation (contingency coefficient 0.685) and good contingency with HLAR (kappa 0.940). The high rates of HLAR may cause a serious problem for combination therapy of aminoglycoside with β-lactams against A. baumannii infections. As armA was

  15. [Vancomycin and high-level aminoglycoside resistant Enterococcus carriage and the risk factors related to resistance in hospitalized patients].

    PubMed

    Yildirim, Mustafa; Sencan, Irfan; Ozdemir, Davut; Oksüz, Sükrü; Yilmaz, Zeynep; Sahin, Idris

    2007-04-01

    The aims of this study were to detect the prevalence of fecal vancomycin resistant Enterococcus (VRE) colonization with high-level resistance to aminoglycoside and other antibiotics and, the risk factors related to resistance in hospitalized patients in Düzce Medical Faculty Hospital, Turkey. A total of 105 patients (61 from internal medicine, 44 from surgery clinics; 54.3% female, mean age: 47.2 +/- 24.54 years) were included to the study and a single stool sample was collected from each of the patients. Specimens were cultivated in Enterococcus selective media (BioMerieux, France), and the isolates were identified by conventional microbiological methods together with the API 20 Strep test. Beta-lactamase activities of the isolates were tested with nitrocefin disk, and antibiotic susceptibilities were determined by the disk diffusion method. Enterococcus spp. were isolated from 81 (77%) of the patients' samples and 60.5% were identified as E. faecium, 13.6% as E. faecalis, 11.1% as E. gallinarum, 7.4% as E. durans, 2.5% as E. raffinosus, 2.5% as E. mundtii, 1.2% as E. casseliflavus, and 1.2% as E. avium. High-level streptomycin and gentamicin resistance rates were found in 19.8% and 9.9% of the isolates, respectively. The resistance rates for the other antibiotics were found as follows; 18.5% to ampicillin, 27.2% to penicilin, 34.6% to nitrofurantoin, 65.4% to norfloxacin, and 70.4% to both tetracycline and ciprofloxacin. No vancomycin resistance was detected, and none of the enterococci had beta-lactamase activity. Long hospitalization period, antibiotic usage and experience of intra-abdominal operation were found as the significant risk factors for colonization of the resistant bacteria. Our results demonstrated that there was no fecal VRE carriage in our hospital during the study period, however, it was concluded that the screening tests should be done periodically in order to detect resistant strains as soon as possible.

  16. Fall armyworm and corn earworm resistance in the breeding crosses of maize inbreds with high levels of phytoalexins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to develop maize germplasm with resistance to multiple insect pests and aflatoxin accumulation, a set of reciprocal breeding crosses was made using maize inbred lines with high levels of kauralexins or zealexins. The evaluation of the breeding crosses for insect resistance utilized the rand...

  17. Universal high-level primary metronidazole resistance in Helicobacter pylori isolated from children in Egypt.

    PubMed

    Sherif, May; Mohran, Zaynab; Fathy, Hanan; Rockabrand, David M; Rozmajzl, Patrick J; Frenck, Robert W

    2004-10-01

    Antimicrobial susceptibility testing was performed on 48 isolates of Helicobacter pylori recovered from Egyptian children undergoing routine endoscopies. The isolates were universally highly resistant to metronidazole, but resistance to other tested antimicrobial agents was rare (4% for clarithromycin, erythromycin, and azithromycin resistance versus 2% for ciprofloxacin and ampicillin resistance). Use of metronidazole for the treatment of H. pylori in Egypt should be avoided.

  18. Emergence of High-Level Daptomycin Resistance in Corynebacterium striatum in Two Patients with Left Ventricular Assist Device Infections

    PubMed Central

    Werth, Brian J.; Hahn, William O.; Butler-Wu, Susan M.

    2016-01-01

    Introduction: We describe the clinical and microbiologic courses of two patients with ventricular assist device infections secondary to Corynebacterium striatum treated with daptomycin. In both cases, the pathogen was initially susceptible to daptomycin (minimum inhibitory concentration [MIC] <0.125 mg/L) but became resistant (MIC >256 mg/L) during therapy. Methods: The clonal nature of the isolates was determined by pulse-field gel electrophoresis (PFGE). Daptomycin binding was assessed by fluorescence microscopy using daptomycin–boron-dipyrromethene (bodipy). Induction and stability of daptomycin resistance were assessed by culturing strains in the presence of low concentrations of daptomycin or passage of resistant strains on daptomycin-free medium and repeat MIC testing, respectively. Results: PFGE revealed that resistant clinical isolates were genetically indistinguishable from their parent strains, but the two pairs were unrelated to each other. The resistant strains had 7.5–15 times lower binding of daptomycin-bodipy compared to the related susceptible strains (p ≤ 0.0002). High-level daptomycin resistance (MIC >256 mg/L) was generated in vitro for both susceptible parent strains after overnight culture in the presence of daptomycin. One of the resistant strains maintained a high-level resistance phenotype up to 5 days of passage on daptomycin-free medium, whereas the other strain reverted back to a susceptible phenotype (MIC = 0.38 mg/L) after one passage on daptomycin-free medium, with a concomitant increase in daptomycin binding. Conclusions: High-level daptomycin resistance in C. striatum was readily generated in vitro and during the course of therapy in these patients. This resistance appears to be mediated by reduced daptomycin binding. Providers should be cautious about using long-term daptomycin monotherapy for C. striatum infections. PMID:26544621

  19. De Novo Characterization of Genes That Contribute to High-Level Ciprofloxacin Resistance in Escherichia coli

    PubMed Central

    Tran, Thu; Ran, Qinghong; Ostrer, Lev

    2016-01-01

    Sensitization of resistant bacteria to existing antibiotics depends on the identification of candidate targets whose activities contribute to resistance. Using a transposon insertion library in an Escherichia coli mutant that was 2,000 times less susceptible to ciprofloxacin than its parent and the relative fitness scores, we identified 19 genes that contributed to the acquired ciprofloxacin resistance and mapped the shortest genetic path that increased the antibiotic susceptibility of the resistant bacteria back to a near wild-type level. PMID:27431218

  20. Novel Plasmids and Resistance Phenotypes in Yersinia pestis: Unique Plasmid Inventory of Strain Java 9 Mediates High Levels of Arsenic Resistance

    PubMed Central

    Eppinger, Mark; Radnedge, Lyndsay; Andersen, Gary; Vietri, Nicholas; Severson, Grant; Mou, Sherry; Ravel, Jacques; Worsham, Patricia L.

    2012-01-01

    Growing evidence suggests that the plasmid repertoire of Yersinia pestis is not restricted to the three classical virulence plasmids. The Java 9 strain of Y. pestis is a biovar Orientalis isolate obtained from a rat in Indonesia. Although it lacks the Y. pestis-specific plasmid pMT, which encodes the F1 capsule, it retains virulence in mouse and non-human primate animal models. While comparing diverse Y. pestis strains using subtractive hybridization, we identified sequences in Java 9 that were homologous to a Y. enterocolitica strain carrying the transposon Tn2502, which is known to encode arsenic resistance. Here we demonstrate that Java 9 exhibits high levels of arsenic and arsenite resistance mediated by a novel promiscuous class II transposon, named Tn2503. Arsenic resistance was self-transmissible from Java 9 to other Y. pestis strains via conjugation. Genomic analysis of the atypical plasmid inventory of Java 9 identified pCD and pPCP plasmids of atypical size and two previously uncharacterized cryptic plasmids. Unlike the Tn2502-mediated arsenic resistance encoded on the Y. enterocolitica virulence plasmid; the resistance loci in Java 9 are found on all four indigenous plasmids, including the two novel cryptic plasmids. This unique mobilome introduces more than 105 genes into the species gene pool. The majority of these are encoded by the two entirely novel self-transmissible plasmids, which show partial homology and synteny to other enterics. In contrast to the reductive evolution in Y. pestis, this study underlines the major impact of a dynamic mobilome and lateral acquisition in the genome evolution of the plague bacterium. PMID:22479347

  1. High-level and novel mechanisms of carbapenem resistance in Gram-negative bacteria from tertiary hospitals in Nigeria.

    PubMed

    Ogbolu, D O; Webber, M A

    2014-05-01

    To determine the occurrence and molecular basis of carbapenem resistance in Gram-negative bacteria from tertiary hospitals in Nigeria, 182 non-duplicate Gram-negative bacterial isolates were investigated for antimicrobial susceptibility, presence of carbapenemases (tested phenotypically and genotypically), random amplified polymorphic DNA (RAPD) typing, plasmid sizing and replicon typing. Minimum inhibitory concentrations of carbapenems showed a high degree of resistance, with 67 isolates (36.8%) being resistant to all carbapenems, of which 40 (59.7%) produced enzymes able to hydrolyse imipenem. PCR and sequencing identified only 10 isolates (5.5%) carrying known carbapenemase genes, including bla(NDM), bla(VIM) and bla(GES). The majority of phenotypically carbapenem-resistant and carbapenemase-producing isolates did not carry a known carbapenemase gene. Transconjugant or transformant plasmid sizes were estimated to be 115 kb for bla(NDM)- and 93 kb for bla(VIM)-carrying plasmids. These plasmids were untypeable for replicon/incompatibility and transferred various other genes including plasmid-mediated quinolone resistance (PMQR) genes and bla(CTX-M-15). Typing showed that the isolates in this study were not clonally related. There is a high level of carbapenem resistance in Nigeria. As well as the globally relevant carbapenemases (bla(NDM), bla(VIM) and bla(GES)), there are other unknown gene(s) or variant(s) in circulation able to hydrolyse carbapenems and confer high-level resistance.

  2. High Levels of Transmitted HIV Drug Resistance in a Study in Papua New Guinea

    PubMed Central

    Lavu, Evelyn; Kave, Ellan; Mosoro, Euodia; Markby, Jessica; Aleksic, Eman; Gare, Janet; Elsum, Imogen A.; Nano, Gideon; Kaima, Petronia; Dala, Nick; Gurung, Anup; Bertagnolio, Silvia; Crowe, Suzanne M.; Myatt, Mark

    2017-01-01

    Introduction Papua New Guinea is a Pacific Island nation of 7.3 million people with an estimated HIV prevalence of 0.8%. ART initiation and monitoring are guided by clinical staging and CD4 cell counts, when available. Little is known about levels of transmitted HIV drug resistance in recently infected individuals in Papua New Guinea. Methods Surveillance of transmitted HIV drug resistance in a total of 123 individuals recently infected with HIV and aged less than 30 years was implemented in Port Moresby (n = 62) and Mount Hagen (n = 61) during the period May 2013-April 2014. HIV drug resistance testing was performed using dried blood spots. Transmitted HIV drug resistance was defined by the presence of one or more drug resistance mutations as defined by the World Health Organization surveillance drug resistance mutations list. Results The prevalence of non-nucleoside reverse transcriptase inhibitor transmitted HIV drug resistance was 16.1% (95% CI 8.8%-27.4%) and 8.2% (95% CI 3.2%-18.2%) in Port Moresby and Mount Hagen, respectively. The prevalence of nucleoside reverse transcriptase inhibitor transmitted HIV drug resistance was 3.2% (95% CI 0.2%-11.7%) and 3.3% (95% CI 0.2%-11.8%) in Port Moresby and Mount Hagen, respectively. No protease inhibitor transmitted HIV drug resistance was observed. Conclusions The level of non-nucleoside reverse transcriptase inhibitor drug resistance in antiretroviral drug naïve individuals recently infected with HIV in Port Moresby is amongst the highest reported globally. This alarming level of transmitted HIV drug resistance in a young sexually active population threatens to limit the on-going effective use of NNRTIs as a component of first-line ART in Papua New Guinea. To support the choice of nationally recommended first-line antiretroviral therapy, representative surveillance of HIV drug resistance among antiretroviral therapy initiators in Papua New Guinea should be urgently implemented. PMID:28146591

  3. Evolution of high-level, multiple anthelmintic resistance on a sheep farm in Malaysia.

    PubMed

    Chandrawathani, P; Waller, P J; Adnan, M; Höglund, J

    2003-02-01

    Anthelmintic resistance in nematode parasites of sheep and goats on a government farm in north Malaysia was monitored over a 3-year period (1997-2000). The faecal egg count reduction test (FECRT) was conducted on young sheep at the beginning and end of this period. Changes in management, designed to reduce the selection pressure for the development of anthelmintic resistance, were also implemented during this time. By far the most important parasite problem was Haemonchus contortus. In 1997, this nematode was found to be resistant to levamisole, with suspected resistance to closantel and moxidectin. However, when the FECRT was repeated 3 years later, its resistance status had become much more severe, with resistance to benzimidazole, levamisole and ivermectin, and suspected resistance to moxidectin. This rapid evolution to multiple anthelmintic resistance is a major concern that needs to be arrested. There is an urgent need to evaluate other control strategies that incorporate livestock management, the 'smart' use of drugs and non-chemotherapeutic approaches, such as biological control agents.

  4. High level of resistance to aztreonam and ticarcillin in Pseudomonas aeruginosa isolated from soil of different crops in Brazil.

    PubMed

    Pitondo-Silva, André; Martins, Vinicius Vicente; Fernandes, Ana Flavia Tonelli; Stehling, Eliana Guedes

    2014-03-01

    Pseudomonas aeruginosa can be found in water, soil, plants and, human and animal fecal samples. It is an important nosocomial pathogenic agent characterized by an intrinsic resistance to multiple antimicrobial agents and the ability to develop high-level (acquired) multidrug resistance through some mechanisms, among them, by the acquisition of plasmids and integrons, which are mobile genetic elements. In this study, 40 isolates from Brazilian soil were analyzed for antibiotic resistance, presence of integrons and plasmidial profile. The results demonstrated that the vast majority of the isolates have shown resistance for aztreonam (92.5%, n=37) and ticarcillin (85%, n=34), four isolates presented plasmids and eight isolates possess the class 1 integron. These results demonstrated that environmental isolates of P. aeruginosa possess surprising antibiotic resistance profile to aztreonam and ticarcillin, two antimicrobial agents for clinical treatment of cystic fibrosis patients and other infections occurred by P. aeruginosa.

  5. High-level Multi-Resistant and Virulent Escherichia coli in Abeokuta, Nigeria.

    PubMed

    Akinduti, Paul Akinniyi; Aboderin, Bukola W; Oloyede, Rasaq; Ogiogwa, Joseph I; Motayo, Babatunde O; Ejilude, Oluwaseun

    2016-01-01

    Multi-resistant Escherichia coli (E. coli) strains co-harboring virulence genes is a cause of high morbidity in Abeokuta, Nigeria. This study was designed to determine some virulent factors among enteropathogenic E. coli in Abeokuta, Nigeria. Approximately non-repetitive 102 isolates of E. coli were recovered from clinical samples from two health facilities in Abeokuta. Biotyping using API and antibiotic susceptibility was determined, and eae and flic genes were assayed by PCR. Antibiotic resistance relatedness was performed by DendroUPGMA. Results showed that 48.0% and 52.0 % were intestinal and extra-intestinal E. coli, ampicillin recorded 100% resistance, amoxycilli/clavulanic acid 64.7%, cotrimoxazole 57.8% and 56.8% resistance against cefotaxime, at MIC >16 ug/mL, 100%, 57.8%, and 50% have MIC50 to ampicillin, tetracycline, and ceftazidime, while 74.5% and 48.0% have MIC90 to ampicillin and ceftazidime. Significant rates of 4.9%, 7.8%, and 9.8% flic, eae, and flic/eae genes were found in intestinal isolates, while 2.9%, 2.0%, and 3.9% were found in extra-intestinal (P < 0.05). Two major clades of the resistant isolates reveal significant antibiotic relatedness among intestinal and extra-intestinal isolates, at 54% resistance similarities with very high multi-antibiotic resistance index of 1.0 (MARI). A high rate of undetected virulent E. coli pathotypes with high resistance could trigger unprecedented morbidity and mortality, mostly among children and the elderly.

  6. High-Level Nickel Resistance in Alcaligenes xylosoxydans 31A and Alcaligenes eutrophus KTO2

    PubMed Central

    Schmidt, Thomas; Stoppel, Ralf-D.; Schlegel, Hans G.

    1991-01-01

    Two new nickel-resistant strains of Alcaligenes species were selected from a large number (about 400) of strains isolated from ecosystems polluted by heavy metals and were studied on the physiological and molecular level. Alcaligenes xylosoxydans 31A is a heterotrophic bacterium, and Alcaligenes eutrophus KTO2 is an autotrophic aerobic hydrogen-oxidizing bacterium. Both strains carry—among other plasmids—a megaplasmid determining resistance to 20 to 50 mM NiCl2 and 20 mM CoCl2 (when growing in defined Tris-buffered media). Megaplasmids pTOM8, pTOM9 from strain 31A, and pGOE2 from strain KTO2 confer nickel resistance to the same degree to transconjugants of all strains of A. eutrophus tested but were not transferred to Escherichia coli. However, DNA fragments carrying the nickel resistance genes, cloned into broad-hostrange vector pVDZ'2, confer resistance to A. eutrophus derivatives as well as E. coli. The DNA fragments of both bacteria, TBA8, TBA9, and GBA (14.5-kb BamHI fragments), appear to be identical. They share equal size, restriction maps, and strong DNA homology but are largely different from fragment HKI of nickel-cobalt resistance plasmid pMOL28 of A. eutrophus CH34. Images PMID:16348590

  7. Draft Genome Sequence of a High-Level Colistin-Resistant Clinical Strain of the Enterobacter cloacae Complex

    PubMed Central

    Lin, Ji; Zhao, Feifei; Feng, Yu

    2017-01-01

    ABSTRACT Strain WCHECl-C4 of the Enterobacter cloacae complex, recovered from the blood of a patient with peritonitis, was high-level resistant to colistin. Here, we report its 5.1-Mb draft genome sequence, comprising 92 contigs with an average 55.74% G+C content. The genome contained 4,783 coding sequences and 68 tRNA genes. PMID:28385849

  8. Draft Genome Sequences of Streptococcus pneumoniae with High-Level Resistance to Respiratory Fluoroquinolones.

    PubMed

    Keness, Yoram; Bisharat, Naiel

    2016-03-31

    Streptococcus pneumoniaeis the leading cause of community-acquired pneumonia. Levofloxacin is a fluoroquinolone used for treatment of severe community-acquired pneumonia. Here, we describe the draft genome sequences ofS. pneumoniaewith emerging resistance to levofloxacin, resulting in failure of treatment of pneumococcal pneumonia.

  9. Abdominal Obesity and Insulin Resistance in People Exposed to Moderate-to-High Levels of Dioxin.

    PubMed

    Chang, Jung-Wei; Chen, Hsiu-Ling; Su, Huey-Jen; Lee, Ching-Chang

    2016-01-01

    Obesity, a risk factor for developing metabolic complications, is a major public health problem. Abdominal obesity is strongly accompanied by a cluster of metabolic abnormalities characterized by insulin resistance. The link between persistent organic pollutants (POPs) and insulin resistance has been investigated in animal and epidemiological studies. We aimed to examine whether insulin resistance is greater in people with abdominal obesity (AO) and concomitant exposure to serum dioxins (PCDD/Fs). We conducted a cross-sectional descriptive study of 2876 participants living near a PCDD/Fs contaminated area. Seventeen 2,3,7,8-substituted PCDD/Fs congeners were measured, and then the associations between the main predictor variable, serum TEQDF-1998, abdominal obesity (AO), dependent variables, and insulin resistance were examined. Twelve of the 17 congeners, widely distributed among PCDDs, and PCDFs, had trends for associations with abdominal adiposity. In men, the highest quintiles of 1,2,3,7,8-PeCDF; 1,2,3,7,8-PeCDD; 2,3,7,8-TCDD; 2,3,7,8-TCDF; and 2,3,4,7,8-PeCDF had the top five adjusted odds ratios (AORs) + 95% confidence intervals (CIs):[4.2; 2.7-6.4], [3.6; 2.3-5.7], [3.2; 2.1-5.0], [3.0; 2.0-4.5], and [2.9; 1.9-4.7], respectively. In women, the highest quintiles of 1,2,3,4,7,8,9-HpCDF; 1,2,3,6,7,8-HxCDF; and 1,2,3,4,6,7,8-HpCDF had the top three AORs + 95% CIs:[3.0; 1.9-4.7], [2.0; 1.3-3.1], and [1.9; 1.3-2.9], respectively. After confounding factors had been adjusted for, men, but not women, with higher serum TEQDF-1998 levels or abdominal obesity had a significantly (Ptrend < 0.001) greater risk for abnormal insulin resistance. The groups with the highest joint serum TEQDF-1998 and abdominal obesity levels were associated with elevated insulin resistance at 5.0 times the odds of the groups with the lowest joint levels (AOR 5.23; 95% CI: 3.53-7.77). We hypothesize that serum TEQDF-1998 and abdominal obesity affect the association with insulin resistance in

  10. Abdominal Obesity and Insulin Resistance in People Exposed to Moderate-to-High Levels of Dioxin

    PubMed Central

    Chang, Jung-Wei; Chen, Hsiu-Ling; Su, Huey-Jen; Lee, Ching-Chang

    2016-01-01

    Obesity, a risk factor for developing metabolic complications, is a major public health problem. Abdominal obesity is strongly accompanied by a cluster of metabolic abnormalities characterized by insulin resistance. The link between persistent organic pollutants (POPs) and insulin resistance has been investigated in animal and epidemiological studies. We aimed to examine whether insulin resistance is greater in people with abdominal obesity (AO) and concomitant exposure to serum dioxins (PCDD/Fs). We conducted a cross-sectional descriptive study of 2876 participants living near a PCDD/Fs contaminated area. Seventeen 2,3,7,8-substituted PCDD/Fs congeners were measured, and then the associations between the main predictor variable, serum TEQDF-1998, abdominal obesity (AO), dependent variables, and insulin resistance were examined. Twelve of the 17 congeners, widely distributed among PCDDs, and PCDFs, had trends for associations with abdominal adiposity. In men, the highest quintiles of 1,2,3,7,8-PeCDF; 1,2,3,7,8-PeCDD; 2,3,7,8-TCDD; 2,3,7,8-TCDF; and 2,3,4,7,8-PeCDF had the top five adjusted odds ratios (AORs) + 95% confidence intervals (CIs):[4.2; 2.7–6.4], [3.6; 2.3–5.7], [3.2; 2.1–5.0], [3.0; 2.0–4.5], and [2.9; 1.9–4.7], respectively. In women, the highest quintiles of 1,2,3,4,7,8,9-HpCDF; 1,2,3,6,7,8-HxCDF; and 1,2,3,4,6,7,8-HpCDF had the top three AORs + 95% CIs:[3.0; 1.9–4.7], [2.0; 1.3–3.1], and [1.9; 1.3–2.9], respectively. After confounding factors had been adjusted for, men, but not women, with higher serum TEQDF-1998 levels or abdominal obesity had a significantly (Ptrend < 0.001) greater risk for abnormal insulin resistance. The groups with the highest joint serum TEQDF-1998 and abdominal obesity levels were associated with elevated insulin resistance at 5.0 times the odds of the groups with the lowest joint levels (AOR 5.23; 95% CI: 3.53–7.77). We hypothesize that serum TEQDF-1998 and abdominal obesity affect the association with

  11. High-Level Chromate Resistance in Arthrobacter sp. strain FB24 Requires Previously Uncharacterized Accessory Genes

    SciTech Connect

    Henne, Kristene L.; Nakatsu, Cindy N.; Thompson, Dorothea K.; Konopka, Allan

    2009-09-24

    The annotated genome sequence of Arthrobacter sp. strain FB24 revealed a chromate resistance determinant (CRD): a cluster of 8 genes located on a 10.6 kb fragment of a 96 kb plasmid. The CRD includes chrA, which encodes a putative chromate efflux protein, and three genes with amino acid similarities to the amino and carboxy termini of ChrB, a putative regulatory protein. There are also three novel genes that have not been previously associated with chromate resistance in other bacteria; they encode an oxidoreductase (most similar to malate:quinone oxidoreductase), a functionally unknown protein with a WD40 repeat domain and a lipoprotein. A chromate-sensitive mutant (strain D11) was generated by curing FB24 of its 96-kb plasmid. Elemental analysis indicated that chromate-exposed cells of strain D11 accumulated three times more chromium than strain FB24. Introduction of the CRD into strain D11 conferred chromate resistance comparable to wild-type levels, whereas deletion of specific regions of the CRD led to decreased resistance. Using real-time reverse transcriptase PCR, we show that expression of each gene within the CRD is specifically induced in response to chromate but not by lead, hydrogen peroxide or arsenate. Higher levels of chrA expression were achieved when the chrB orthologs and the WD40 repeat domain genes were present, suggesting their regulatory roles. Collectively, our findings indicate that chromate resistance in strain FB24 is primarily achieved by plasmid-mediated chromate efflux with the contribution of previously unrecognized accessory genes.

  12. High level multiple antibiotic resistance among fish surface associated bacterial populations in non-aquaculture freshwater environment.

    PubMed

    Ozaktas, Tugba; Taskin, Bilgin; Gozen, Ayse G

    2012-12-01

    Freshwater fish, Alburnus alburnus (bleak), were captured from Lake Mogan, situated in Ankara, during spring. The surface mucus of the fish was collected and associated bacteria were cultured and isolated. By sequencing PCR-amplified 16S RNA encoding genes, the isolates were identified as members of 12 different genera: Acinetobacter, Aeromonas, Bacillus, Brevundimonas, Gordonia, Kocuria, Microbacterium, Mycobacterium, Pseudomonas, Rhodococcus, and Staphylococcus, in addition to one strain that was unidentified. The mucus-dwelling bacterial isolates were tested for resistance against ampicillin, kanamycin, streptomycin and chloramphenicol. About 95% of the isolates were found to be resistant to ampicillin, 93% to chloramphenicol, and 88% to kanamycin and streptomycin. A Microbacterium oxydans and the unidentified environmental isolate were resistant to all four antibiotics tested at very high levels (>1600 μg/ml ampicillin and streptomycin; >1120 μg/ml kanamycin; >960 μg/ml chloramphenicol). Only a Kocuria sp. was sensitive to all four antibiotics at the lowest concentrations tested (3.10 μg/ml ampicillin and streptomycin; 2.15 μg/ml kanamycin; 1.85 μg/ml chloramphenicol). The rest of the isolates showed different resistance levels. Plasmid isolations were carried out to determine if the multiple antibiotic resistance could be attributed to the presence of plasmids. However, no plasmid was detected in any of the isolates. The resistance appeared to be mediated by chromosome-associated functions. This study indicated that multiple antibiotic resistance at moderate to high levels is common among the current phenotypes of the fish mucus-dwelling bacterial populations in this temperate, shallow lake which has not been subjected to any aquaculturing so far but under anthropogenic effect being in a recreational area.

  13. High-level vancomycin resistant Enterococcus faecium related to humans and pigs found in dust from pig breeding facilities.

    PubMed

    Braga, Teresa M; Pomba, Constança; Lopes, M Fátima Silva

    2013-01-25

    Environmental dust from animal breeding facilities was never screened for the presence of enterococci, nor of vancomycin-resistant enterococci (VRE), despite the possibility of being a vehicle of transmission of strains and antibiotic resistance genes between food-producing animals and man. Bio-security measures in pig facilities include disinfection with biocides to avoid the dissemination of opportunistic pathogenic bacteria, namely enterococci and in particular VRE. We thus undertook collection of enterococci and VRE in a representative number of breeding pig facilities in Portugal (n=171) and analyzed their susceptibility to benzalkonium chloride (BC) and chlorhexidine (CHX). A prevalence of 15% of VRE was found, with 6% high-level resistance found, and MIC values for CHX and BC were similar to those commonly found among enterococcal isolates from related environments, 8 μg/ml and 4 μg/ml, respectively. Among the isolated high-level vancomycin resistant Enterococcus faecium carrying the vanA genotype, we found multilocus sequence types closely related to pig and human isolates from European countries and Brazil. These results strongly advise constant surveillance of this environment and its inclusion in future epidemiologic studies on VRE.

  14. High levels of inflammation and insulin resistance in obstructive sleep apnea patients with hypertension.

    PubMed

    Qian, Xiaoshun; Yin, Tong; Li, Tianzhi; Kang, Chunyan; Guo, Ruibiao; Sun, Baojun; Liu, Changting

    2012-08-01

    Hypertension induced by obstructive sleep apnea (OSA) may be multifactorial in origin, and systemic inflammation is one of the major factors. However, OSA patients do not always have the identical probability with hypertension even in patients with the same history and degree of OSA. The aim of this study was to compare the levels of inflammation and insulin resistance in two groups of patients who had the same degree as well as the same long history of OSA, but with/without hypertension. OSA patients (Apnea Hyponea Index, AHI ≥ 40/h, n = 70) were examined by polysomnography and blood analysis for the measurements of fasting plasma glucose, serum insulin (FINS), high-sensitivity C-reactive protein (CRP), peptide C,TNF-α, IL-6, and IL-10. Patients with hypertension (n = 40) had higher level of LDL-C and lower HDL-C levels than patients without hypertension. Almost half (16/40) of OSA patients with hypertension had family history of hypertension. Moreover in OSA patients with hypertension, the levels of TNF-α, IL-6, and CRP were higher, but IL-10 was lower than those without hypertension. FINS, peptide C, HOMA-IR, and HOMA-islet were also higher in OSA patients with hypertension. OSA patients with hypertension have higher level of inflammation and insulin resistance. Systemic inflammation and insulin resistance are both important factors for the development of hypertension in OSA patients.

  15. High-Level Primary Clarithromycin Resistance of Helicobacter pylori in Algiers, Algeria: A Prospective Multicenter Molecular Study.

    PubMed

    Djennane-Hadibi, Fazia; Bachtarzi, Mohamed; Layaida, Karim; Ali Arous, Nassima; Nakmouche, Mhamed; Saadi, Berkane; Tazir, Mohamed; Ramdani-Bouguessa, Nadjia; Burucoa, Christophe

    2016-04-01

    Knowledge of local antibiotic resistance is crucial to adaptation for the choice of the optimal first-line treatment for Helicobacter pylori infection. Clarithromycin is a key component of the standard triple therapy largely used worldwide and, more particularly, in Algeria. Clarithromycin resistance is the main risk factor for treatment failure. The aim of this study was to evaluate, for the first time in Algeria, the prevalence of the primary resistance of H. pylori to clarithromycin. We conducted a prospective study (2008-2014) that included 195 Algerian patients referred for gastroduodenal endoscopy to two University Hospitals, one General Hospital, and several private gastroenterologists in Algiers (Algeria). One gastric biopsy was collected for the molecular detection of H. pylori and the mutations in 23S rRNA genes that confer resistance to clarithromycin with a quadruplex real-time PCR using Scorpion primers. The Scorpion PCR detected H. pylori DNA in 91 biopsies (47%). A mutation conferring resistance to clarithromycin was detected in 32 of the 91 positive patients (35%) and in 29 of the 88 positive patients never previously treated for an H. pylori infection (33%). The prevalence of primary resistance of H. pylori to clarithromycin was 33% in the Algerian population being studied. The high level of primary clarithromycin resistance in the H. pylori strains infecting the Algerian population that we report leads us to recommend the abandonment of the standard clarithromycin-based triple therapy as a first-line treatment in Algeria.

  16. Studies of Corrosion Resistant Materials Being Considered for High-Level Nuclear Waste Containment in Yucca Mountain Relevant Environments

    SciTech Connect

    McCright, R.D.; Ilevbare, G.; Estill, J.; Rebak, R.

    2001-12-09

    Containment of spent nuclear fuel and vitrified forms of high level nuclear waste require use of materials that are highly corrosion resistant to all of the anticipated environmental scenarios that can occur in a geological repository. Ni-Cr-Mo Alloy 22 (UNS N60622) is proposed for the corrosion resistant outer barrier of a two-layer waste package container at the potential repository site at Yucca Mountain. A range of water compositions that may contact the outer barrier is under consideration, and a testing program is underway to characterize the forms of corrosion and to quantify the corrosion rates. Results from the testing support models for long term prediction of the performance of the container. Results obtained to date indicate a very low general corrosion rate for Alloy 22 and very high resistance to all forms of localized and environmentally assisted cracking in environments tested to date.

  17. High levels of pre-treatment HIV drug resistance and treatment failure in Nigerian children

    PubMed Central

    Boerma, Ragna S; Boender, T Sonia; Sigaloff, Kim C.E.; Rinke de Wit, Tobias F; van Hensbroek, Michael Boele; Ndembi, Nicaise; Adeyemo, Titilope; Temiye, Edamisan O; Osibogun, Akin; Ondoa, Pascale; Calis, Job C; Akanmu, Alani Sulaimon

    2016-01-01

    Introduction Pre-treatment HIV drug resistance (PDR) is an increasing problem in sub-Saharan Africa. Children are an especially vulnerable population to develop PDR given that paediatric second-line treatment options are limited. Although monitoring of PDR is important, data on the paediatric prevalence in sub-Saharan Africa and its consequences for treatment outcomes are scarce. We designed a prospective paediatric cohort study to document the prevalence of PDR and its effect on subsequent treatment failure in Nigeria, the country with the second highest number of HIV-infected children in the world. Methods HIV-1-infected children ≤12 years, who had not been exposed to drugs for the prevention of mother-to-child transmission (PMTCT), were enrolled between 2012 and 2013, and followed up for 24 months in Lagos, Nigeria. Pre-antiretroviral treatment (ART) population-based pol genotypic testing and six-monthly viral load (VL) testing were performed. Logistic regression analysis was used to assess the effect of PDR (World Health Organization (WHO) list for transmitted drug resistance) on subsequent treatment failure (two consecutive VL measurements >1000 cps/ml or death). Results Of the total 82 PMTCT-naïve children, 13 (15.9%) had PDR. All 13 children harboured non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations, of whom seven also had nucleoside reverse transcriptase inhibitor resistance. After 24 months, 33% had experienced treatment failure. Treatment failure was associated with PDR and a higher log VL before treatment initiation (adjusted odds ratio (aOR) 7.53 (95%CI 1.61–35.15) and 2.85 (95%CI 1.04–7.78), respectively). Discussion PDR was present in one out of six Nigerian children. These high numbers corroborate with recent findings in other African countries. The presence of PDR was relevant as it was the strongest predictor of first-line treatment failure. Conclusions Our findings stress the importance of implementing fully active regimens

  18. Effects of medium and inoculum variations on screening for high-level aminoglycoside resistance in Enterococcus faecalis.

    PubMed Central

    Sahm, D F; Torres, C

    1988-01-01

    Enterococcus faecalis isolates that are refractory to aminoglycoside-penicillin synergy can be detected by their ability to grow in the presence of high concentrations of aminoglycoside (2,000 micrograms/ml). In past studies investigators have used a variety of media and inoculum sizes to perform high-level aminoglycoside resistance screens, but little is known about how these variations affect test accuracy. We screened 63 E. faecalis strains on different media by using various inoculum sizes and correlated the results with synergy test results obtained by time-kill studies. Screens were done with dextrose-phosphate agar, brain heart infusion agar, Trypticase soy agar with 5% sheep blood, Mueller-Hinton agar with 5% sheep blood, dextrose-phosphate broth, and Mueller-Hinton broth. Agar screens were inoculated with 10(2), 10(4), and 10(6) CFU; and broth screens contained a final inoculum of 10(5) CFU/ml. The E. faecalis isolates were tested for high-level resistance to streptomycin, kanamycin, amikacin, gentamicin, and tobramycin. Of the 63 isolates tested, 21 did not show high-level resistance to any of the aminoglycosides tested, and 42 demonstrated high-level resistance to one or more drugs. The sensitivity of most screens was greater than or equal to 90%. Regardless of the inoculum size or medium used, false-resistance results were seldom encountered. Screen specificity, which was used as the indicator of false susceptibility, was markedly influenced by both the inoculum size and the drug being tested. Specificity was low whenever a 10(2)-CFU inoculum was used, when amikacin was tested with any inoculum, and when tobramycin was tested in broth media. Data for kanamycin could be used to predict amikacin-penicillin synergy, and the highly accurate gentamicin screen obviated the need for the testing of tobramycin. We recommend a 10(6) -CFU inoculum for agar screens and a 10(5) -CFU/ml inoculum for broth screens. The type of medium used did not substantially

  19. In vitro activity of older and newer fluoroquinolones against efflux-mediated high-level ciprofloxacin-resistant Streptococcus pneumoniae.

    PubMed

    Daporta, Matilde Trigo; Muñoz Bellido, Juan Luis; Guirao, Genoveva Yagüe; Hernández, Manuel Segovia; García-Rodríguez, José Angel

    2004-08-01

    The effect of high-level efflux activity on the MICs of fluoroquinolones against Streptococcus pneumoniae in the absence of topoisomerase mutations leading to fluoroquinolones resistance was investigated. A S. pneumoniae ATCC 46619-derived strain with high-level efflux activity was obtained (SP-25A). Both the parent and obtained strains were tested against efflux substrates acriflavine (Acr) and ethidium bromide (EtBr), and against norfloxacin (NFX), ciprofloxacin (CFX), levofloxacin (LFX), moxifloxacin (MFX), trovafloxacin (TVX) and sitafloxacin (SFX), in presence and absence of the efflux pump inhibitor reserpine. gyrA, gyrB, parC and parE QRDR genes were amplified by PCR and sequenced. MICs of NFX and CFX against SP-25A were 64-fold higher than parent strain MICs (256 mg/L versus 4 mg/L and 64 mg/L versus 1mg/L, respectively). MIC of LFX increased from 1 to 4 mg/L and MICs of MFX, TVX and SFX remained virtually unchanged (0.1-0.2 mg/L). MICs of Acr and EtBr against SP-25A were 8- and 16-fold higher than against parent strains. In both cases, reserpine reverted MICs to the parent strain values (1 and 0.2 mg/L). Only parE showed two mutations leading to a Pro(454) --> Ser and Glu(443) changes, which have previously been shown not to lead to significant fluoroquinolones MIC increases. SP-25A showed a significant increase of MICs of the hydrophilic fluoroquinolones, apparently derived only from efflux activity. Efflux activity, at these high levels, can lead to high-level resistance to older hydrophilic fluoroquinolones, but does affect newer fluoroquinolones such as moxifloxacin, trovafloxacin and sitafloxacin.

  20. Prevalence of carbapenemases among high-level aminoglycoside-resistant Acinetobacter baumannii isolates in a university hospital in China

    PubMed Central

    Wang, Yanhong; Shen, Min; Yang, Jingni; Dai, Min; Chang, Yaowen; Zhang, Chi; Luan, Guangxin; Ling, Baodong; Jia, Xu

    2016-01-01

    The prevalence of aminoglycoside resistant enzymes has previously been reported and extended-spectrum β-lactamase among Acinetobacter baumannii. To track the risk of multidrug-resistant A. baumannii, the present study aimed to determine the prevalence of carbapenemases in high-level aminoglycoside resistant A. baumannii over two years. A total of 118 strains of A. baumannii were consecutively collected in the First Affiliated Hospital of Chengdu Medical College, Chengdu, China. These isolates were investigated on the genetic basis of their resistance to aminoglycosides. The results showed that 75 (63.56%) isolates were high-level resistant to aminoglycosides, including gentamicin and amikacin (minimum inhibitory concentration, ≥256 µg/ml). Aminoglycoside-resistant genes ant(2″)-Ia, aac(6′)-Ib, aph(3′)-Ia, aac(3)-Ia, aac(3)-IIa, armA, rmtA, rmtB, rmtC, rmtD, rmtE, rmtF, rmtG, rmtH and npmA, and carbapenem-resistant genes blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, blaSIM, blaIMP, blaNDM-1 and blaKPC, were analyzed using polymerase chain reaction. The positive rate of ant(2″)-Ia, aac(6′)-Ib, aph(3′)-Ia, aac(3)-Ia and aac(3)-IIa was 66.95, 69.49, 42.37, 39.83 and 14.41%, respectively. armA was present in 72.0% (54/75) of A. baumannii isolates with high-level resistance to aminoglycosides. The remaining nine 16S ribosomal RNA methlyase genes (rmtA, rmtB, rmtC, rmtD, rmtE, rmtF, rmtG, rmtH and npmA) and aminoglycoside-modifying enzyme gene aac(6′)-Ib-cr were not detected. Among the 54 armA-positive isolates, the prevalence of the carbapenem resistant blaOXA-23 and blaOXA-51 genes was 79.63 and 100%, respectively. armA, ant(2″)-Ia and aac(6′)-Ib were positive in 43 isolates. The results of multilocus sequence typing revealed 31 sequence types (STs) in all clinical strains. Among these STs, the high-level aminoglycoside-resistant A. baumannii ST92, which mostly harbored blaOXA-23, was the predominant clone (29/75). In conclusion, A. baumannii

  1. Investigation of the reformulated Remel Synergy Quad plate for detection of high-level aminoglycoside and vancomycin resistance among enterococci.

    PubMed

    Free, L; Sahm, D F

    1995-06-01

    We investigated the accuracy of the recently released Remel Synergy Quad plate, a commercially available agar screening method for detecting high-level aminoglycoside and vancomycin resistance among enterococci that is based on the National Committee for Clinical Laboratory Standards recommended guidelines (National Committee for Clinical Laboratory Standards, M7-A3, 1993). The Synergy Quad correctly determined the gentamicin and streptomycin resistance status for > or = 97% of 147 Enterococcus faecalis and Enterococcus faecium isolates tested. Detection of vancomycin resistance also was reliable, as no false susceptibility occurred with 36 vancomycin-resistant E. faecalis and E. faecium strains and false resistance occurred only once with the 47 susceptible strains tested. One strain each of Enterococcus gallinarum and Enterococcus casseliflavus failed to grow on the screen, but because the true nature and significance of resistance in such isolates is unknown the implication of their screen negativity is uncertain. In summary, the Remel Synergy Quad provides a highly accurate and convenient method for susceptibility testing of enterococci against gentamicin, streptomycin, and vancomycin.

  2. Evaluation of the Kirby-Bauer disc diffusion test as a screening test for high-level aminoglycoside resistance in enterococci.

    PubMed

    Pfaller, M A; Niles, A C; Murray, P R

    1984-10-01

    The Kirby-Bauer disc diffusion test was evaluated as a test to detect high-level aminoglycoside (streptomycin, kanamycin, tobramycin, and gentamicin) resistance in isolates of enterococci. The authors found that high-level resistance could not be predicted accurately with the diffusion test.

  3. Impaired fitness of human immunodeficiency virus type 1 variants with high-level resistance to protease inhibitors.

    PubMed Central

    Croteau, G; Doyon, L; Thibeault, D; McKercher, G; Pilote, L; Lamarre, D

    1997-01-01

    One hope to maintain the benefits of antiviral therapy against the human immunodeficiency virus type 1 (HIV-1), despite the development of resistance, is the possibility that resistant variants will show decreased viral fitness. To study this possibility, HIV-1 variants showing high-level resistance (up to 1,500-fold) to the substrate analog protease inhibitors BILA 1906 BS and BILA 2185 BS have been characterized. Active-site mutations V32I and I84V/A were consistently observed in the protease of highly resistant viruses, along with up to six other mutations. In vitro studies with recombinant mutant proteases demonstrated that these mutations resulted in up to 10(4)-fold increases in the Ki values toward BILA 1906 BS and BILA 2185 BS and a concomitant 2,200-fold decrease in catalytic efficiency of the enzymes toward a synthetic substrate. When introduced into viral molecular clones, the protease mutations impaired polyprotein processing, consistent with a decrease in enzyme activity in virions. Despite these observations, however, most mutations had little effect on viral replication except when the active-site mutations V32I and I84V/A were coexpressed in the protease. The latter combinations not only conferred a significant growth reduction of viral clones on peripheral blood mononuclear cells but also caused the complete disappearance of mutated clones when cocultured with wild-type virus on T-cell lines. Furthermore, the double nucleotide mutation I84A rapidly reverted to I84V upon drug removal, confirming its impact on viral fitness. Therefore, high-level resistance to protease inhibitors can be associated with impaired viral fitness, suggesting that antiviral therapies with such inhibitors may maintain some clinical benefits. PMID:8995629

  4. High-level carbapenem resistance in a Citrobacter freundii clinical isolate is due to a combination of KPC-2 production and decreased porin expression.

    PubMed

    Zhang, Rong; Yang, Lijiang; Cai, Jia Chang; Zhou, Hong Wei; Chen, Gong-Xiang

    2008-03-01

    An imipenem-resistant isolate of Citrobacter freundii ZJ163 (MIC 256 microg ml(-1)) isolated from a Chinese hospital was investigated. The C. freundii ZJ163 isolate exhibited high-level resistance to carbapenems, penicillins, cephalosporins, cefoxitin, aztreonam, quinolones and aminoglycosides. Isoelectric focusing (IEF) demonstrated three beta-lactamases with pIs of 5.4 (TEM-1), 6.7 (KPC-2) and 7.9 (CTX-M-14). Two different transconjugants (types A and B) were obtained by conjugation studies. The type A transconjugant exhibited reduced susceptibility or resistance to penicillins, cephalosporins and aztreonam, but was susceptible to carbapenems, quinolones and aminoglycosides. The antimicrobial susceptibility patterns of the type B transconjugant were similar to that of type A, except for its significantly reduced carbapenem susceptibility (imipenem MIC 2 microg ml(-1)). IEF, specific PCRs and DNA sequence analysis indicated that the type A transconjugant produced CTX-M-14 beta-lactamase with a pI of 7.9, that the type B transconjugant produced KPC-2 beta-lactamase with a pI of 6.7 and that the beta-lactamase with a pI of 5.4 was TEM-1. PCR analysis and sequencing confirmed the presence of the ampC gene in the chromosomal DNA from C. freundii ZJ163, although no activity of AmpC beta-lactamase was detected by IEF. Urea/SDS-PAGE analysis of outer-membrane proteins revealed that the levels of the 41 and 38 kDa porins were decreased in C. freundii ZJ163. It was concluded that production of KPC-2 combined with decreased expression of porins contributes to high-level resistance to carbapenems in C. freundii ZJ163.

  5. An Environmental Shiga Toxin-Producing Escherichia coli O145 Clonal Population Exhibits High-Level Phenotypic Variation That Includes Virulence Traits

    PubMed Central

    Quinones, Beatriz; He, Xiaohua; Zhong, Wayne; Louie, Jacqueline W.; Lee, Bertram G.; Yambao, Jaszemyn C.; Mandrell, Robert E.; Cooley, Michael B.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) serotype O145 is one of the major non-O157 serotypes associated with severe human disease. Here we examined the genetic diversity, population structure, virulence potential, and antimicrobial resistance profiles of environmental O145 strains recovered from a major produce production region in California. Multilocus sequence typing analyses revealed that sequence type 78 (ST-78), a common ST in clinical strains, was the predominant genotype among the environmental strains. Similarly, all California environmental strains belonged to H28, a common H serotype in clinical strains. Although most environmental strains carried an intact fliC gene, only one strain retained swimming motility. Diverse stx subtypes were identified, including stx1a, stx2a, stx2c, and stx2e. Although no correlation was detected between the stx genotype and Stx1 production, high Stx2 production was detected mainly in strains carrying stx2a only and was correlated positively with the cytotoxicity of Shiga toxin. All environmental strains were capable of producing enterohemolysin, whereas only 10 strains were positive for anaerobic hemolytic activity. Multidrug resistance appeared to be common, as nearly half of the tested O145 strains displayed resistance to at least two different classes of antibiotics. The core virulence determinants of enterohemorrhagic E. coli were conserved in the environmental STEC O145 strains; however, there was large variation in the expression of virulence traits among the strains that were highly related genotypically, implying a trend of clonal divergence. Several cattle isolates exhibited key virulence traits comparable to those of the STEC O145 outbreak strains, emphasizing the emergence of hypervirulent strains in agricultural environments. PMID:26637597

  6. High-level expression of alternative oxidase protein sequences enhances the spread of viral vectors in resistant and susceptible plants.

    PubMed

    Murphy, Alex M; Gilliland, Androulla; York, Caroline J; Hyman, Belinda; Carr, John P

    2004-12-01

    The alternative oxidase (AOX) is the terminal oxidase of the cyanide-resistant alternative respiratory pathway in plants and has been implicated in resistance to viruses. When tobacco mosaic virus (TMV) vectors were used to drive very high levels of expression of either AOX or AOX mutated in its active site (AOX-E), virus spread was enhanced. This was visualized as the induction of larger hypersensitive-response lesions after inoculation onto NN-genotype tobacco than those produced by vectors bearing sequences of comparable length [the green fluorescent protein (gfp) gene sequence or antisense aox] or the 'empty' viral vector. Also, in the highly susceptible host Nicotiana benthamiana, systemic movement of TMV vectors expressing AOX or AOX-E was faster than that of TMV constructs bearing gfp or antisense aox sequences. Notably, in N. benthamiana, TMV.AOX and TMV.AOX-E induced symptoms that were severe and ultimately included cell death, whereas the empty vector, TMV.GFP and the TMV vector expressing antisense aox sequences never induced necrosis. The results show that, if expressed at sufficiently high levels, active and inactive AOX proteins can affect virus spread and symptomology in plants.

  7. Arabidopsis Mutant bik1 Exhibits Strong Resistance to Plasmodiophora brassicae

    PubMed Central

    Chen, Tao; Bi, Kai; He, Zhangchao; Gao, Zhixiao; Zhao, Ying; Fu, Yanping; Cheng, Jiasen; Xie, Jiatao; Jiang, Daohong

    2016-01-01

    Botrytis-induced kinase1 (BIK1), a receptor-like cytoplasmic kinase, plays an important role in resistance against pathogens and insects in Arabidopsis thaliana. However, it remains unknown whether BIK1 functions against Plasmodiophora brassicae, an obligate biotrophic protist that attacks cruciferous plants and induces gall formation on roots. Here, we investigated the potential roles of receptors FLS2, BAK1, and BIK1 in the infection of P. brassicae cruciferous plants. Wild-type plants, fls2, and bak1 mutants showed typical symptom on roots, and the galls were filled with large quantities of resting spores, while bik1 mutant plants exhibited strong resistance to P. brassicae. Compared with that of the wild-type plants, the root hair and cortical infection rate of bik1 mutant were significantly reduced by about 40–50%. A considerable portion of bik1 roots failed to form typical galls. Even if some small galls were formed, they were filled with multinucleate secondary plasmodia. The bik1 plants accumulated less reactive oxygen species (ROS) at infected roots than other mutants and wild-type plants. Exogenous salicylic acid (SA) treatment alleviated the clubroot symptoms in wild-type plants, and the expression of the SA signaling marker gene PR1 was significantly increased in bik1. Both sid2 (salicylic acid induction-deficient 2) and npr1-1 [non-expresser of PR genes that regulate systemic acquired resistance (SAR)] mutants showed increased susceptibility to P. brassicae compared with wild-type plants. These results suggest that the resistance of bik1 to P. brassicae is possibly mediated by SA inducible mechanisms. PMID:27679580

  8. A three amino acid deletion in the transmembrane domain of the nicotinic acetylcholine receptor α6 subunit confers high-level resistance to spinosad in Plutella xylostella

    PubMed Central

    Wang, Jing; Wang, Xingliang; Lansdell, Stuart J.; Zhang, Jianheng; Millar, Neil S.; Wu, Yidong

    2016-01-01

    Spinosad is a macrocyclic lactone insecticide that acts primarily at the nicotinic acetylcholine receptors (nAChRs) of target insects. Here we describe evidence that high levels of resistance to spinosad in the diamondback moth (Plutella xylostella) are associated with a three amino acid (3-aa) deletion in the fourth transmembrane domain (TM4) of the nAChR α6 subunit (Pxα6). Following laboratory selection with spinosad, the SZ-SpinR strain of P. xylostella exhibited 940-fold resistance to spinosad. In addition, the selected insect population had 1060-fold cross-resistance to spinetoram but, in contrast, no cross-resistance to abamectin was observed. Genetic analysis indicates that spinosad resistance in SZ-SpinR is inherited as a recessive and autosomal trait, and that the 3-aa deletion (IIA) in TM4 of Pxα6 is tightly linked to spinosad resistance. Because of well-established difficulties in functional expression of cloned insect nAChRs, the analogous resistance-associated deletion mutation was introduced into a prototype nAChR (the cloned human α7 subunit). Two-electrode voltage-clamp recording with wild-type and mutated nAChRs expressed in Xenopus laevis oocytes indicated that the mutation causes a complete loss of agonist activation. In addition, radioligand binding studies indicated that the 3-aa deletion resulted in significantly lower-affinity binding of the extracellular neurotransmitter-binding site. These findings are consistent with the 3-amino acid (IIA) deletion within the transmembrane domain of Pxα6 being responsible for target-site resistance to spinosad in the SZ-SpinR strain of P. xylostella. PMID:26855198

  9. Frequency of biocide-resistant genes and susceptibility to chlorhexidine in high-level mupirocin-resistant, methicillin-resistant Staphylococcus aureus (MuH MRSA).

    PubMed

    Liu, Qingzhong; Zhao, Huanqiang; Han, Lizhong; Shu, Wen; Wu, Qiong; Ni, Yuxing

    2015-08-01

    The aim of this study was to determine the prevalence of biocide-resistant determinants and the susceptibility to chlorhexidine in high-level mupirocin-resistant, methicillin-resistant Staphylococcus aureus (MuH MRSA). Fifty-three MuH MRSA isolates were analyzed for plasmid-borne genes (qacA/B, smr, qacG, qacH, and qacJ) by polymerase chain reaction (PCR); for chromosome-mediated genes (norA, norB, norC, mepA, mdeA, sepA, and sdrM) by PCR and quantitative reverse transcription-PCR (qRT-PCR); and for susceptibility to chlorhexidine by MIC and minimum bactericidal concentration (MBC). Furthermore, disinfectant efficacy was tested in the presence of 3.0% bovine serum albumin (BSA) in MBC detection. The plasmid-borne genes qacA/B (83.0%) and smr (77.4%) and overexpressions of chromosome-mediated genes norA (49.0%) and norB (28.8%) were predominantly found in isolates studied, and 90.6% of the isolates revealed tolerance to chlorhexidine. In the presence of BSA, the average MBC of chlorhexidine for these isolates rose to 256 μg/mL. Altogether, our results suggest that surveillance of sensitivity to biocides among MuH MRSA isolates is essential for hospital infection control.

  10. High-level tolerance to triclosan may play a role in Pseudomonas aeruginosa antibiotic resistance in immunocompromised hosts: evidence from outbreak investigation

    PubMed Central

    2012-01-01

    Background and methods Pseudomonas aeruginosa is a major infectious threat to immunocompromised patients. We recently reported a fatal epidemic of multidrug-resistant P. aeruginosa in an onchoematology unit, linked to massive contamination of a triclosan-based disinfectant. The aim of this study is to evaluate the antimicrobial activity of triclosan and chlorhexidine digluconate against the epidemic strain of P. aeruginosa, to confirm the hypothesis that the soap dispenser acted as a continuous source of the infection during the outbreak, and to explore the potential role of triclosan in increasing the level of resistance to selected antibiotics. Susceptibility tests and time-kill assays for disinfectans were performed using two commercial formulations containing triclosan and chlorhexidine digluconate, respectively. Antibiotic susceptibility testing was performed by the broth microdilution method. Findings The P. aeruginosa epidemic strain exhibited an extremely high level of triclosan resistance (apparent MIC = 2,125 mg/L), while it was markedly susceptible to chlorhexidine digluconate (apparent MIC = 12.5 mg/L). Upon gradual adaptation to triclosan, the epidemic strain survived for a long period (> 120 h) in the presence of 3,400 mg/L (equivalent to 1.6 × MIC) of triclosan, concomitantly increasing the resistance to six antibiotics that are typical substrates of drug efflux pumps of the resistance nodulation division family. This effect was reversed by efflux pump inhibitors. Conclusions The epidemic P. aeruginosa strain was resistant to triclosan and its previous exposure to triclosan increases antibiotic resistance, likely through active efflux mechanisms. Since P. aeruginosa can become tolerant to elevated triclosan concentrations, the use of triclosan-based disinfectants should be avoided in those healthcare settings hosting patients at high risk for P. aeruginosa infection. PMID:22260715

  11. Interference in Pheromone-Responsive Conjugation of a High-Level Bacitracin Resistant Enterococcus faecalis Plasmid of Poultry Origin

    PubMed Central

    Tremblay, Cindy-Love; Archambault, Marie

    2013-01-01

    The current study reports on contact interference of a high-level bacitracin- resistant pheromone-responsive plasmid of Enterococcus faecalis strain 543 of poultry origin during conjugative transfer of bcr antimicrobial resistance genes using a polyclonal antiserum aggregation substance44–560 (AS). After induction with pheromones produced by the recipient strain E. faecalis JH2-2, clumping of the donor E. faecalis strain 543 was observed as well as high transfer frequencies of bcr in short time broth mating. Filter mating assays from donor strain E. faecalis 543 to the recipient strain E. faecalis JH2-2 revealed conjugative transfer of asa1 (AS), bcrRAB and traB (negative regulator pheromone response) genes. The presence of these genes in transconjugants was confirmed by antimicrobial susceptibility testing, PCR, Southern hybridization and sequencing. A significant reduction in formation of aggregates was observed when the polyclonal anti-AS44–560 was added in the pheromone-responsive conjugation experiments as compared to the induced state. Moreover, interference of anti-AS44–560 antibodies in pheromone-responsive conjugation was demonstrated by a reduction in horizontal transfer of asa1 and bcr genes between E. faecalis strain 543 and E. faecalis JH2-2. Reducing the pheromone-responsive conjugation of E. faecalis is of interest because of its clinical importance in the horizontal transfer of antimicrobial resistance. PMID:24030654

  12. Detection of the esp gene in high-level gentamicin resistant Enterococcus faecalis strains from pet animals in Japan.

    PubMed

    Harada, Tetsuya; Tsuji, Noboru; Otsuki, Koichi; Murase, Toshiyuki

    2005-03-20

    We investigated the prevalence of the esp gene and the susceptibility to gentamicin in Enterococcus faecalis and E. faecium strains obtained from pet animals. Nine of 30 E. faecalis and 2 of 38 E. faecium strains from the pet animals had the esp gene. Three esp-positive E. faecalis strains, which were isolated from two dogs and a cat, showed gentamicin MICs of > or =256 microg/ml and harbored the high-level gentamicin resistance (HLGR) gene, aac(6')-Ie-aph(2'')-Ia. Of the nine esp-positive E. faecalis strains, five, including the three strains with the HLGR gene, were closely related by numerical analysis of PFGE patterns. Longitudinal investigation needs to elucidate whether the HLGR gene was incorporated into a subpopulation of the esp-positive E. faecalis.

  13. Transgenic wheat carrying a barley UDP-glucosyltransferase exhibit high levels of Fusarium head blight resistance by detoxifying trichothecenes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight (FHB) is a worldwide disease of wheat and barley, mainly caused by Fusarium graminearum. During infection, the fungal pathogen produces trichothecene mycotoxins, such as deoxynivalenol (DON) and nivalenol (NIV) that increase fungal virulence. Moreover, grains contaminated with t...

  14. Characterisation of clinical meticillin-resistant Staphylococcus epidermidis demonstrating high levels of linezolid resistance (>256 μg/ml) resulting from transmissible and mutational mechanisms.

    PubMed

    Gabriel, Emma M; Fitzgibbon, Siobhan; Clair, James; Coffey, Aidan; O'Mahony, Jim M

    2015-07-01

    Staphylococcus epidermidis (S. epidermidis), one of the leading etiological agents of nosocomial infections poses a significant economic burden globally. Introduced in 2000, linezolid (LZD) has become an important antibiotic, used in nearly seventy countries worldwide to treat infections caused by Gram-positive pathogens such as meticillin-resistant Staphylococcus and Streptococcus species along with vancomycin-resistant enterococci. Resistance to LZD in clinical settings remains rare. Here, we report the emergence of meticillin resistant S. epidermidis (MRSE) clinical isolates from two voluntary general acute hospitals exhibiting higher than typically reported levels of LZD resistance (MIC>256 μg/ml). The MRSE ST-2 clone isolated from eight patients (2010-2011) not only possessed resistance-conferring mutations such as G2576T in domain V of 23S rRNA gene (as determined by HRM-PCR analysis) and R172C substitution in the ribosomal protein L3, but also carried the cfr gene (the only known transmissible mechanism of LZD resistance). All isolates possessed several key biofilm-associated genes (such as icaA, icaD, aap and atlE) and resistance to multiple clinically significant antibiotics was recorded. This study reports the earliest incidence (2010) of clinical MRSE in the Republic of Ireland demonstrating multiple LZD resistance mechanisms both mutational and potentially transmissible, and characterises this emerging resistance from a molecular perspective.

  15. Characterization of high-level daptomycin resistance in Viridans group Streptococci developed upon in vitro exposure to daptomycin.

    PubMed

    Akins, Ronda L; Katz, Bradley D; Monahan, Catherine; Alexander, Dylan

    2015-04-01

    Viridans group streptococci (VGS) are part of the normal flora that may cause bacteremia, often leading to endocarditis. We evaluated daptomycin against four clinical strains of VGS (MICs = 1 or 2 μg/ml) using an in vitro-simulated endocardial vegetation model, a simulated bacteremia model, and kill curves. Daptomycin exposure was simulated at 6 mg/kg of body weight and 8 mg/kg every 24 h for endocardial and bacteremia models. Total drug concentrations were used for analyses containing protein (albumin and pooled human serum), and free (unbound) drug concentrations (93% protein bound) were used for analyses not containing protein. Daptomycin MICs in the presence of protein were significantly higher than those in the absence of protein. Despite MICs below or at the susceptible breakpoint, all daptomycin regimens demonstrated limited kill in both pharmacodynamic models. A reduction of approximately 1 to 2 log10 CFU was seen for all isolates and dosages except daptomycin at 6 mg/kg, which achieved a reduction of 2.7 log10 CFU/g against one strain (Streptococcus gordonii 1649) in the endocardial model. Activity was similar in both pharmacodynamic models in the presence or absence of protein. Similar activity was noted in the kill curves over all multiples of the MIC. Regrowth by 24 h was seen even at 8× MIC. Postexposure daptomycin MICs for both pharmacodynamic models increased to >256 μg/ml for all isolates by 24 and 72 h. Despite susceptibility to daptomycin by standard MIC methods, these VGS developed high-level daptomycin resistance (HLDR) after a short duration following drug exposure not attributed to modification or inactivation of daptomycin. Further evaluation is warranted to determine the mechanism of resistance and clinical implications.

  16. Characterization of High-Level Daptomycin Resistance in Viridans Group Streptococci Developed upon In Vitro Exposure to Daptomycin

    PubMed Central

    Katz, Bradley D.; Monahan, Catherine; Alexander, Dylan

    2015-01-01

    Viridans group streptococci (VGS) are part of the normal flora that may cause bacteremia, often leading to endocarditis. We evaluated daptomycin against four clinical strains of VGS (MICs = 1 or 2 μg/ml) using an in vitro-simulated endocardial vegetation model, a simulated bacteremia model, and kill curves. Daptomycin exposure was simulated at 6 mg/kg of body weight and 8 mg/kg every 24 h for endocardial and bacteremia models. Total drug concentrations were used for analyses containing protein (albumin and pooled human serum), and free (unbound) drug concentrations (93% protein bound) were used for analyses not containing protein. Daptomycin MICs in the presence of protein were significantly higher than those in the absence of protein. Despite MICs below or at the susceptible breakpoint, all daptomycin regimens demonstrated limited kill in both pharmacodynamic models. A reduction of approximately 1 to 2 log10 CFU was seen for all isolates and dosages except daptomycin at 6 mg/kg, which achieved a reduction of 2.7 log10 CFU/g against one strain (Streptococcus gordonii 1649) in the endocardial model. Activity was similar in both pharmacodynamic models in the presence or absence of protein. Similar activity was noted in the kill curves over all multiples of the MIC. Regrowth by 24 h was seen even at 8× MIC. Postexposure daptomycin MICs for both pharmacodynamic models increased to >256 μg/ml for all isolates by 24 and 72 h. Despite susceptibility to daptomycin by standard MIC methods, these VGS developed high-level daptomycin resistance (HLDR) after a short duration following drug exposure not attributed to modification or inactivation of daptomycin. Further evaluation is warranted to determine the mechanism of resistance and clinical implications. PMID:25624330

  17. Comparative Study of Bacteremias Caused by Enterococcus spp. with and without High-Level Resistance to Gentamicin

    PubMed Central

    Caballero-Granado, Francisco Javier; Cisneros, J. M.; Luque, R.; Torres-Tortosa, M.; Gamboa, F.; Díez, F.; Villanueva, J. L.; Pérez-Cano, R.; Pasquau, J.; Merino, D.; Menchero, A.; Mora, D.; López-Ruz, M. A.; Vergara, A.; Infecciosas, for the Grupo Andaluz Para El Estudio De Las Enfermedades

    1998-01-01

    A prospective, multicenter study was carried out over a period of 10 months. All patients with clinically significant bacteremia caused by Enterococcus spp. were included. The epidemiological, microbiological, clinical, and prognostic features and the relationship of these features to the presence of high-level resistance to gentamicin (HLRG) were studied. Ninety-three patients with enterococcal bacteremia were included, and 31 of these cases were caused by HLRG (33%). The multivariate analysis selected chronic renal failure, intensive care unit stay, previous use of antimicrobial agents, and Enterococcus faecalis species as the independent risk factors that influenced the development of HLRG. The strains with HLRG showed lower levels of susceptibility to penicillin and ciprofloxacin. Clinical features (except for chronic renal failure) were similar in both groups of patients. HLRG did not influence the prognosis for patients with enterococcal bacteremia in terms of either the crude mortality rate (29% for patients with bacteremia caused by enterococci with HLRG and 28% for patients not infected with strains with HLRG) or the hospital stay after the acquisition of enterococcal bacteremia. Hemodynamic compromise, inappropriate antimicrobial therapy, and mechanical ventilation were revealed in the multivariate analysis to be the independent risk factors for mortality. Prolonged hospitalization was associated with the nosocomial acquisition of bacteremia and polymicrobial infections. PMID:9466769

  18. BRCA2-deficient sarcomatoid mammary tumors exhibit multidrug resistance.

    PubMed

    Jaspers, Janneke E; Sol, Wendy; Kersbergen, Ariena; Schlicker, Andreas; Guyader, Charlotte; Xu, Guotai; Wessels, Lodewyk; Borst, Piet; Jonkers, Jos; Rottenberg, Sven

    2015-02-15

    Pan- or multidrug resistance is a central problem in clinical oncology. Here, we use a genetically engineered mouse model of BRCA2-associated hereditary breast cancer to study drug resistance to several types of chemotherapy and PARP inhibition. We found that multidrug resistance was strongly associated with an EMT-like sarcomatoid phenotype and high expression of the Abcb1b gene, which encodes the drug efflux transporter P-glycoprotein. Inhibition of P-glycoprotein could partly resensitize sarcomatoid tumors to the PARP inhibitor olaparib, docetaxel, and doxorubicin. We propose that multidrug resistance is a multifactorial process and that mouse models are useful to unravel this.

  19. An environmental shiga toxin-producing Escherichia coli O145 clonal population exhibits high-level phenotypic variation that includes virulence traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) serotype O145 is one of the major non-O157 serotypes associated with severe human disease. Here we examined the genetic diversity, population structure, virulence potential, and antibiotic resistance profile of environmental O145 strains isolated from a ...

  20. Canine osteosarcoma cells exhibit resistance to aurora kinase inhibitors.

    PubMed

    Cannon, C M; Pozniak, J; Scott, M C; Ito, D; Gorden, B H; Graef, A J; Modiano, J F

    2015-03-01

    We evaluated the effect of Aurora kinase inhibitors AZD1152 and VX680 on canine osteosarcoma cells. Cytotoxicity was seen in all four cell lines; however, half-maximal inhibitory concentrations were significantly higher than in human leukaemia and canine lymphoma cells. AZD1152 reduced Aurora kinase B phosphorylation, indicating resistance was not because of failure of target recognition. Efflux mediated by ABCB1 and ABCG2 transporters is one known mechanism of resistance against these drugs and verapamil enhanced AZD1152-induced apoptosis; however, these transporters were only expressed by a small percentage of cells in each line and the effects of verapamil were modest, suggesting other mechanisms contribute to resistance. Our results indicate that canine osteosarcoma cells are resistant to Aurora kinase inhibitors and suggest that these compounds are unlikely to be useful as single agents for this disease. Further investigation of these resistance mechanisms and the potential utility of Aurora kinase inhibitors in multi-agent protocols is warranted.

  1. Corrosion resistant iron aluminides exhibiting improved mechanical properties and corrosion resistance

    DOEpatents

    Liu, C.T.; McKamey, C.G.; Tortorelli, P.F.; David, S.A.

    1994-06-14

    The specification discloses a corrosion-resistant intermetallic alloy comprising, in atomic percent, an FeAl iron aluminide containing from about 30 to about 40% aluminum alloyed with from about 0.01 to 0.4% zirconium and from 0.01 to about 0.8% boron. The alloy exhibits considerably improved room temperature ductility for enhanced usefulness in structural applications. The high temperature strength and fabricability is improved by alloying with molybdenum, carbon, chromium and vanadium. 9 figs.

  2. Corrosion resistant iron aluminides exhibiting improved mechanical properties and corrosion resistance

    DOEpatents

    Liu, Chain T.; McKamey, Claudette G.; Tortorelli, Peter F.; David, Stan A.

    1994-01-01

    The specification discloses a corrosion-resistant intermetallic alloy comprising, in atomic percent, an FeAl iron aluminide containing from about 30 to about 40% aluminum alloyed with from about 0.01 to 0.4% zirconium and from 0.01 to about 0.8% boron. The alloy exhibits considerably improved room temperature ductility for enhanced usefulness in structural applications. The high temperature strength and fabricability is improved by alloying with molybdenum, carbon, chromium and vanadium.

  3. Evolution of high-level ethambutol-resistant tuberculosis through interacting mutations in decaprenylphosphoryl-β-D-arabinose biosynthetic and utilization pathway genes.

    PubMed

    Safi, Hassan; Lingaraju, Subramanya; Amin, Anita; Kim, Soyeon; Jones, Marcus; Holmes, Michael; McNeil, Michael; Peterson, Scott N; Chatterjee, Delphi; Fleischmann, Robert; Alland, David

    2013-10-01

    To study the evolution of drug resistance, we genetically and biochemically characterized Mycobacterium tuberculosis strains selected in vitro for ethambutol resistance. Mutations in decaprenylphosphoryl-β-D-arabinose (DPA) biosynthetic and utilization pathway genes Rv3806c, Rv3792, embB and embC accumulated to produce a wide range of ethambutol minimal inhibitory concentrations (MICs) that depended on mutation type and number. Rv3806c mutations increased DPA synthesis, causing MICs to double from 2 to 4 μg/ml in a wild-type background and to increase from 16 to 32 μg/ml in an embB codon 306 mutant background. Synonymous mutations in Rv3792 increased the expression of downstream embC, an ethambutol target, resulting in MICs of 8 μg/ml. Multistep selection was required for high-level resistance. Mutations in embC or very high embC expression were observed at the highest resistance level. In clinical isolates, Rv3806c mutations were associated with high-level resistance and had multiplicative effects with embB mutations on MICs. Ethambutol resistance is acquired through the acquisition of mutations that interact in complex ways to produce a range of MICs, from those falling below breakpoint values to ones representing high-level resistance.

  4. MAMA-PCR assay for the detection of point mutations associated with high-level erythromycin resistance in Campylobacter jejuni and Campylobacter coli strains.

    PubMed

    Alonso, Rodrigo; Mateo, Estibaliz; Churruca, Estibaliz; Martinez, Irati; Girbau, Cecilia; Fernández-Astorga, Aurora

    2005-10-01

    Twenty Campylobacter jejuni and 16 Campylobacter coli strains isolated from humans and food/animals, including 17 isolates resistant to erythromycin, were analyzed. A combined mismatch amplification mutation assay-PCR technique was developed to detect the mutations A 2074 C and A 2075 G in the 23S rRNA gene associated with erythromycin resistance. All high-level erythromycin-resistant strains examined by DNA sequencing carried the transition mutation A 2075 G, whereas no isolate carried the A 2074 C mutation. No mutations were found among the susceptible and low-level erythromycin-resistant strains.

  5. Descendants of primed Arabidopsis plants exhibit resistance to biotic stress.

    PubMed

    Slaughter, Ana; Daniel, Xavier; Flors, Victor; Luna, Estrella; Hohn, Barbara; Mauch-Mani, Brigitte

    2012-02-01

    An attack of plants by pathogens or treatment with certain resistance-inducing compounds can lead to the establishment of a unique primed state of defense. Primed plants show enhanced defense reactions upon further challenge with biotic or abiotic stress. Here, we report that the primed state in Arabidopsis (Arabidopsis thaliana) is still functional in the next generation without additional treatment. We compared the reactions of Arabidopsis plants that had been either primed with β-amino-butyric acid (BABA) or with an avirulent isolate of the bacteria Pseudomonas syringae pv tomato (PstavrRpt2). The descendants of primed plants showed a faster and higher accumulation of transcripts of defense-related genes in the salicylic acid signaling pathway and enhanced disease resistance upon challenge inoculation with a virulent isolate of P. syringae. In addition, the progeny of primed plants was also more resistant against the oomycete pathogen Hyaloperonospora arabidopsidis. When transgenerationally primed plants were subjected to an additional priming treatment, their descendants displayed an even stronger primed phenotype, suggesting that plants can inherit a sensitization for the priming phenomenon. Interestingly, this primed to be primed phenotype was much reduced in the Arabidopsis β-amino-butyric acid priming mutant ibs1 (induced BABA sterility1). Our results demonstrate that the primed state of plants is transferred to their progeny and confers improved protection from pathogen attack as compared to the descendants of unprimed plants.

  6. Genetic linkage analysis of the lesser grain borer Rhyzopertha dominica identifies two loci that confer high-level resistance to the fumigant phosphine.

    PubMed Central

    Schlipalius, David I; Cheng, Qiang; Reilly, Paul E B; Collins, Patrick J; Ebert, Paul R

    2002-01-01

    High levels of inheritable resistance to phosphine in Rhyzopertha dominica have recently been detected in Australia and in an effort to isolate the genes responsible for resistance we have used random amplified DNA fingerprinting (RAF) to produce a genetic linkage map of R. dominica. The map consists of 94 dominant DNA markers with an average distance between markers of 4.6 cM and defines nine linkage groups with a total recombination distance of 390.1 cM. We have identified two loci that are responsible for high-level resistance. One provides approximately 50x resistance to phosphine while the other provides 12.5x resistance and in combination, the two genes act synergistically to provide a resistance level 250x greater than that of fully susceptible beetles. The haploid genome size has been determined to be 4.76 x 10(8) bp, resulting in an average physical distance of 1.2 Mbp per map unit. No recombination has been observed between either of the two resistance loci and their adjacent DNA markers in a population of 44 fully resistant F5 individuals, which indicates that the genes are likely to reside within 0.91 cM (1.1 Mbp) of the DNA markers. PMID:12072472

  7. High-Level Heat Resistance of Spores of Bacillus amyloliquefaciens and Bacillus licheniformis Results from the Presence of a spoVA Operon in a Tn1546 Transposon.

    PubMed

    Berendsen, Erwin M; Koning, Rosella A; Boekhorst, Jos; de Jong, Anne; Kuipers, Oscar P; Wells-Bennik, Marjon H J

    2016-01-01

    Bacterial endospore formers can produce spores that are resistant to many food processing conditions, including heat. Some spores may survive heating processes aimed at production of commercially sterile foods. Recently, it was shown that a spoVA operon, designated spoVA(2mob), present on a Tn1546 transposon in Bacillus subtilis, leads to profoundly increased wet heat resistance of B. subtilis spores. Such Tn1546 transposon elements including the spoVA(2mob) operon were also found in several strains of Bacillus amyloliquefaciens and Bacillus licheniformis, and these strains were shown to produce spores with significantly higher resistances to wet heat than their counterparts lacking this transposon. In this study, the locations and compositions of Tn1546 transposons encompassing the spoVA(2mob) operons in B. amyloliquefaciens and B. licheniformis were analyzed. Introduction of these spoVA(2mob) operons into B. subtilis 168 (producing spores that are not highly heat resistant) rendered mutant 168 strains that produced high-level heat resistant spores, demonstrating that these elements in B. amyloliquefaciens and B. licheniformis are responsible for high level heat resistance of spores. Assessment of growth of the nine strains of each species between 5.2°C and 57.7°C showed some differences between strains, especially at lower temperatures, but all strains were able to grow at 57.7°C. Strains of B. amyloliquefaciens and B. licheniformis that contain the Tn1546 elements (and produce high-level heat resistant spores) grew at temperatures similar to those of their Tn1546-negative counterparts that produce low-level heat resistant spores. The findings presented in this study allow for detection of B. amyloliquefaciens and B. licheniformis strains that produce highly heat resistant spores in the food chain.

  8. High-Level Heat Resistance of Spores of Bacillus amyloliquefaciens and Bacillus licheniformis Results from the Presence of a spoVA Operon in a Tn1546 Transposon

    PubMed Central

    Berendsen, Erwin M.; Koning, Rosella A.; Boekhorst, Jos; de Jong, Anne; Kuipers, Oscar P.; Wells-Bennik, Marjon H. J.

    2016-01-01

    Bacterial endospore formers can produce spores that are resistant to many food processing conditions, including heat. Some spores may survive heating processes aimed at production of commercially sterile foods. Recently, it was shown that a spoVA operon, designated spoVA2mob, present on a Tn1546 transposon in Bacillus subtilis, leads to profoundly increased wet heat resistance of B. subtilis spores. Such Tn1546 transposon elements including the spoVA2mob operon were also found in several strains of Bacillus amyloliquefaciens and Bacillus licheniformis, and these strains were shown to produce spores with significantly higher resistances to wet heat than their counterparts lacking this transposon. In this study, the locations and compositions of Tn1546 transposons encompassing the spoVA2mob operons in B. amyloliquefaciens and B. licheniformis were analyzed. Introduction of these spoVA2mob operons into B. subtilis 168 (producing spores that are not highly heat resistant) rendered mutant 168 strains that produced high-level heat resistant spores, demonstrating that these elements in B. amyloliquefaciens and B. licheniformis are responsible for high level heat resistance of spores. Assessment of growth of the nine strains of each species between 5.2°C and 57.7°C showed some differences between strains, especially at lower temperatures, but all strains were able to grow at 57.7°C. Strains of B. amyloliquefaciens and B. licheniformis that contain the Tn1546 elements (and produce high-level heat resistant spores) grew at temperatures similar to those of their Tn1546-negative counterparts that produce low-level heat resistant spores. The findings presented in this study allow for detection of B. amyloliquefaciens and B. licheniformis strains that produce highly heat resistant spores in the food chain. PMID:27994575

  9. Mycobacterium tuberculosis rrs A1401G mutation correlates with high-level resistance to kanamycin, amikacin, and capreomycin in clinical isolates from mainland China.

    PubMed

    Du, Qinglin; Dai, Guangming; Long, Quanxin; Yu, Xia; Dong, Lingling; Huang, Hairong; Xie, Jianping

    2013-10-01

    Mutations correlating phenotypic resistance level with the injectable second-line anti-tuberculosis drugs (SLDs) including kanamycin (KAN), amikacin (AMK), and capreomycin (CAP) remain elusive. A collection of 114 Mycobacterium tuberculosis clinical isolates from mainland China was analyzed. The minimum inhibitory concentration (MIC) of each strain was determined and the sequences of rrs, tlyA, promoter of eis as well as 5' untranslated region (UTR) of whiB7 were amplified and sequenced. No mutation in tlyA, promoter of eis and 5' UTR of whiB7, was found to be associated with resistance among these samples. Sequencing data of 1400 rrs region demonstrated the A1401G mutation in rrs was prevalent, which presented in 84% of the KAN resistant isolates while only in about 50% of the AMK or CAP resistant isolates. Furthermore, most of the resistant isolates with A1401G mutation showed high-level resistance to these injectable SLDs. In conclusion, our results suggest the rrs A1401G mutation was related to high-level resistance to KAN, AMK, and CAP in M. tuberculosis isolates from mainland China.

  10. Evolution of a Double Amino Acid Substitution in the 5-Enolpyruvylshikimate-3-Phosphate Synthase in Eleusine indica Conferring High-Level Glyphosate Resistance1

    PubMed Central

    Yu, Qin; Jalaludin, Adam; Han, Heping; Chen, Ming; Sammons, R. Douglas; Powles, Stephen B.

    2015-01-01

    Glyphosate is the most important and widely used herbicide in world agriculture. Intensive glyphosate selection has resulted in the widespread evolution of glyphosate-resistant weed populations, threatening the sustainability of this valuable once-in-a-century agrochemical. Field-evolved glyphosate resistance due to known resistance mechanisms is generally low to modest. Here, working with a highly glyphosate-resistant Eleusine indica population, we identified a double amino acid substitution (T102I + P106S [TIPS]) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene in glyphosate-resistant individuals. This TIPS mutation recreates the biotechnology-engineered commercial first generation glyphosate-tolerant EPSPS in corn (Zea mays) and now in other crops. In E. indica, the naturally evolved TIPS mutants are highly (more than 180-fold) resistant to glyphosate compared with the wild type and more resistant (more than 32-fold) than the previously known P106S mutants. The E. indica TIPS EPSPS showed very high-level (2,647-fold) in vitro resistance to glyphosate relative to the wild type and is more resistant (600-fold) than the P106S variant. The evolution of the TIPS mutation in crop fields under glyphosate selection is likely a sequential event, with the P106S mutation being selected first and fixed, followed by the T102I mutation to create the highly resistant TIPS EPSPS. The sequential evolution of the TIPS mutation endowing high-level glyphosate resistance is an important mechanism by which plants adapt to intense herbicide selection and a dramatic example of evolution in action. PMID:25717039

  11. Evolution of a double amino acid substitution in the 5-enolpyruvylshikimate-3-phosphate synthase in Eleusine indica conferring high-level glyphosate resistance.

    PubMed

    Yu, Qin; Jalaludin, Adam; Han, Heping; Chen, Ming; Sammons, R Douglas; Powles, Stephen B

    2015-04-01

    Glyphosate is the most important and widely used herbicide in world agriculture. Intensive glyphosate selection has resulted in the widespread evolution of glyphosate-resistant weed populations, threatening the sustainability of this valuable once-in-a-century agrochemical. Field-evolved glyphosate resistance due to known resistance mechanisms is generally low to modest. Here, working with a highly glyphosate-resistant Eleusine indica population, we identified a double amino acid substitution (T102I+P106S [TIPS]) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene in glyphosate-resistant individuals. This TIPS mutation recreates the biotechnology-engineered commercial first generation glyphosate-tolerant EPSPS in corn (Zea mays) and now in other crops. In E. indica, the naturally evolved TIPS mutants are highly (more than 180-fold) resistant to glyphosate compared with the wild type and more resistant (more than 32-fold) than the previously known P106S mutants. The E. indica TIPS EPSPS showed very high-level (2,647-fold) in vitro resistance to glyphosate relative to the wild type and is more resistant (600-fold) than the P106S variant. The evolution of the TIPS mutation in crop fields under glyphosate selection is likely a sequential event, with the P106S mutation being selected first and fixed, followed by the T102I mutation to create the highly resistant TIPS EPSPS. The sequential evolution of the TIPS mutation endowing high-level glyphosate resistance is an important mechanism by which plants adapt to intense herbicide selection and a dramatic example of evolution in action.

  12. High level of cross-resistance between kanamycin, amikacin, and capreomycin among Mycobacterium tuberculosis isolates from Georgia and a close relation with mutations in the rrs gene.

    PubMed

    Jugheli, Levan; Bzekalava, Nino; de Rijk, Pim; Fissette, Krista; Portaels, Françoise; Rigouts, Leen

    2009-12-01

    The aminoglycosides kanamycin and amikacin and the macrocyclic peptide capreomycin are key drugs for the treatment of multidrug-resistant tuberculosis (MDR-TB). The increasing rates of resistance to these drugs and the possible cross-resistance between them are concerns for MDR-TB therapy. Mutations in the 16S rRNA gene (rrs) have been associated with resistance to each of the drugs, and mutations of the tlyA gene, which encodes a putative rRNA methyltransferase, are thought to confer capreomycin resistance in Mycobacterium tuberculosis bacteria. Studies of possible cross-resistance have shown variable results. In this study, the MICs of these drugs for 145 clinical isolates from Georgia and the sequences of the rrs and tlyA genes of the isolates were determined. Of 78 kanamycin-resistant strains, 9 (11.5%) were susceptible to amikacin and 16 (20.5%) were susceptible to capreomycin. Four strains were resistant to capreomycin but were susceptible to the other drugs, whereas all amikacin-resistant isolates were resistant to kanamycin. Sequencing revealed six types of mutations in the rrs gene (A514C, C517T, A1401G, C1402T, C1443G, T1521C) but no mutations in the tlyA gene. The A514C, C517T, C1443G, and T1521C mutations showed no association with resistance to any of the drugs. The A1401G and C1402T mutations were observed in 65 kanamycin-resistant isolates and the 4 capreomycin-resistant isolates, respectively, whereas none of the susceptible isolates showed either of those mutations. The four mutants with the C1402T mutations showed high levels of resistance to capreomycin but no resistance to kanamycin and amikacin. Detection of the A1401G mutation appeared to be 100% specific for the detection of resistance to kanamycin and amikacin, while the sensitivities reached 85.9% and 94.2%, respectively.

  13. Identification of QTL controlling high levels of partial resistance to Fusarium solani f. sp. pisi in pea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium root rot is a common biotic restraint on pea yields worldwide and genetic resistance is the most feasible method for improving pea production. This study was conducted to discover quantitative trait loci (QTL) controlling genetic partial resistance to Fusarium root rot caused by Fusarium s...

  14. Evaluations of melon germplasm reported to exhibit host plant resistance to sweetpotato whitefly

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sweetpotato whitefly (MEAM1 cryptic species of Bemisia tabaci; SPWF) displaced B. tabaci biotype A in 1991 in the lower desert area of southern California and the adjoining areas of Arizona and western Mexico. The search for high-level host plant resistance to this devastating insect has been ongoin...

  15. Repression of Invasion Genes and Decreased Invasion in a High-Level Fluoroquinolone-Resistant Salmonella Typhimurium Mutant

    PubMed Central

    Fàbrega, Anna; du Merle, Laurence; Le Bouguénec, Chantal; Jiménez de Anta, M. Teresa; Vila, Jordi

    2009-01-01

    Background Nalidixic acid resistance among Salmonella Typhimurium clinical isolates has steadily increased, whereas the level of ciprofloxacin resistance remains low. The main objective of this study was to characterize the fluoroquinolone resistance mechanisms acquired in a S. Typhimurium mutant selected with ciprofloxacin from a susceptible isolate and to investigate its invasion ability. Methodology/Principal Findings Three different amino acid substitutions were detected in the quinolone target proteins of the resistant mutant (MIC of ciprofloxacin, 64 µg/ml): D87G and G81C in GyrA, and a novel mutation, E470K, in ParE. A protein analysis revealed an increased expression of AcrAB/TolC and decreased expression of OmpC. Sequencing of the marRAB, soxRS, ramR and acrR operons did not show any mutation and neither did their expression levels in a microarray analysis. A decreased percentage of invasion ability was detected when compared with the susceptible clinical isolate in a gentamicin protection assay. The microarray results revealed a decreased expression of genes which play a role during the invasion process, such as hilA, invF and the flhDC operon. Of note was the impaired growth detected in the resistant strain. A strain with a reverted phenotype (mainly concerning the resistance phenotype) was obtained from the resistant mutant. Conclusions/Significance In conclusion, a possible link between fluoroquinolone resistance and decreased cell invasion ability may exist explaining the low prevalence of fluoroquinolone-resistant S. Typhimurium clinical isolates. The impaired growth may appear as a consequence of fluoroquinolone resistance acquisition and down-regulate the expression of the invasion genes. PMID:19946377

  16. Vip3A Resistance Alleles Exist at High Levels in Australian Targets before Release of Cotton Expressing This Toxin

    PubMed Central

    Mahon, Rod J.; Downes, Sharon J.; James, Bill

    2012-01-01

    Crops engineered to produce insecticidal crystal (Cry) proteins from the soil bacterium Bacillus thuringiensis (Bt) have revolutionised pest control in agriculture. However field-level resistance to Bt has developed in some targets. Utilising novel vegetative insecticidal proteins (Vips), also derived from Bt but genetically distinct from Cry toxins, is a possible solution that biotechnical companies intend to employ. Using data collected over two seasons we determined that, before deployment of Vip-expressing plants in Australia, resistance alleles exist in key targets as polymorphisms at frequencies of 0.027 (n = 273 lines, 95% CI = 0.019–0.038) in H. armigera and 0.008 (n = 248 lines, 0.004–0.015) in H. punctigera. These frequencies are above mutation rates normally encountered. Homozygous resistant neonates survived doses of Vip3A higher than those estimated in field-grown plants. Fortunately the resistance is largely, if not completely, recessive and does not confer resistance to the Bt toxins Cry1Ac or Cry2Ab already deployed in cotton crops. These later characteristics are favourable for resistance management; however the robustness of Vip3A inclusive varieties will depend on resistance frequencies to the Cry toxins when it is released (anticipated 2016) and the efficacy of Vip3A throughout the season. It is appropriate to pre-emptively screen key targets of Bt crops elsewhere, especially those such as H. zea in the USA, which is not only closely related to H. armigera but also will be exposed to Vip in several varieties of cotton and corn. PMID:22761737

  17. Vip3A resistance alleles exist at high levels in Australian targets before release of cotton expressing this toxin.

    PubMed

    Mahon, Rod J; Downes, Sharon J; James, Bill

    2012-01-01

    Crops engineered to produce insecticidal crystal (Cry) proteins from the soil bacterium Bacillus thuringiensis (Bt) have revolutionised pest control in agriculture. However field-level resistance to Bt has developed in some targets. Utilising novel vegetative insecticidal proteins (Vips), also derived from Bt but genetically distinct from Cry toxins, is a possible solution that biotechnical companies intend to employ. Using data collected over two seasons we determined that, before deployment of Vip-expressing plants in Australia, resistance alleles exist in key targets as polymorphisms at frequencies of 0.027 (n = 273 lines, 95% CI = 0.019-0.038) in H. armigera and 0.008 (n = 248 lines, 0.004-0.015) in H. punctigera. These frequencies are above mutation rates normally encountered. Homozygous resistant neonates survived doses of Vip3A higher than those estimated in field-grown plants. Fortunately the resistance is largely, if not completely, recessive and does not confer resistance to the Bt toxins Cry1Ac or Cry2Ab already deployed in cotton crops. These later characteristics are favourable for resistance management; however the robustness of Vip3A inclusive varieties will depend on resistance frequencies to the Cry toxins when it is released (anticipated 2016) and the efficacy of Vip3A throughout the season. It is appropriate to pre-emptively screen key targets of Bt crops elsewhere, especially those such as H. zea in the USA, which is not only closely related to H. armigera but also will be exposed to Vip in several varieties of cotton and corn.

  18. High-level quinolone resistance is associated with the overexpression of smeVWX in Stenotrophomonas maltophilia clinical isolates.

    PubMed

    García-León, G; Ruiz de Alegría Puig, C; García de la Fuente, C; Martínez-Martínez, L; Martínez, J L; Sánchez, M B

    2015-05-01

    Stenotrophomonas maltophilia is the only known bacterium in which quinolone-resistant isolates do not present mutations in the genes encoding bacterial topoisomerases. The expression of the intrinsic quinolone resistance elements smeDEF, smeVWX and Smqnr was analysed in 31 clinical S. maltophilia isolates presenting a minimum inhibitory concentration (MIC) range to ciprofloxacin between 0.5 and > 32 μg/mL; 11 (35.5%) overexpressed smeDEF, 2 (6.5%) presenting the highest quinolone MICs overexpressed smeVWX and 1 (3.2%) overexpressed Smqnr. Both strains overexpressing smeVWX presented changes at the Gly266 position of SmeRv, the repressor of smeVWX. Changes at the same position were previously observed in in vitro selected S. maltophilia quinolone-resistant mutants, indicating this amino acid is highly relevant for the activity of SmeRv in repressing smeVWX expression. For the first time SmeVWX overexpression is associated with quinolone resistance of S. maltophilia clinical isolates.

  19. Identification of tolerance to Fusarium root rot in wild pea germplasm with high levels of partial resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium root rot, caused by Fusarium solani f. sp. pisi, is a serious root rot pathogen affecting peas in all pea growing areas of the USA and is damaging in both dryland and irrigated pea fields. Partial resistance to Fusarium root rot in 44 accessions from the Pisum Core Collection located in Pu...

  20. Fasciola hepatica demonstrates high levels of genetic diversity, a lack of population structure and high gene flow: possible implications for drug resistance.

    PubMed

    Beesley, Nicola J; Williams, Diana J L; Paterson, Steve; Hodgkinson, Jane

    2017-01-01

    Fasciola hepatica, the liver fluke, is a trematode parasite of considerable economic importance to the livestock industry and is a re-emerging zoonosis that poses a risk to human health in F. hepatica-endemic areas worldwide. Drug resistance is a substantial threat to the current and future control of F. hepatica, yet little is known about how the biology of the parasite influences the development and spread of resistance. Given that F. hepatica can self-fertilise and therefore inbreed, there is the potential for greater population differentiation and an increased likelihood of recessive alleles, such as drug resistance genes, coming together. This could be compounded by clonal expansion within the snail intermediate host and aggregation of parasites of the same genotype on pasture. Alternatively, widespread movement of animals that typically occurs in the UK could promote high levels of gene flow and prevent population differentiation. We identified clonal parasites with identical multilocus genotypes in 61% of hosts. Despite this, 84% of 1579 adult parasites had unique multilocus genotypes, which supports high levels of genotypic diversity within F. hepatica populations. Our analyses indicate a selfing rate no greater than 2%, suggesting that this diversity is in part due to the propensity for F. hepatica to cross-fertilise. Finally, although we identified high genetic diversity within a given host, there was little evidence for differentiation between populations from different hosts, indicating a single panmictic population. This implies that, once those emerge, anthelmintic resistance genes have the potential to spread rapidly through liver fluke populations.

  1. High-level carbapenem-resistant OXA-48-producing Klebsiella pneumoniae with a novel OmpK36 variant and low-level, carbapenem-resistant, non-porin-deficient, OXA-181-producing Escherichia coli from Thailand.

    PubMed

    Lunha, Kamonwan; Chanawong, Aroonwadee; Lulitanond, Aroonlug; Wilailuckana, Chotechana; Charoensri, Nicha; Wonglakorn, Lumyai; Saenjamla, Pimjai; Chaimanee, Prajuab; Angkititrakul, Sunpetch; Chetchotisakd, Ploenchan

    2016-06-01

    Five blaOXA-48-like-carrying Enterobacteriaceae isolates collected from two Thai patients in December 2012 were characterized. Three Klebsiella pneumoniae isolates giving two different pulsed-field gel electrophoresis patterns and sequence types (ST11 and ST37) from patient 1 harbored blaOXA-48 locating on Tn1999.2, whereas two Escherichia coli isolates with the same pulsotype and ST5 from Patient 2 carried ISEcp1-associated blaOXA-181. One K. pneumoniae strain had blaSHV-12, blaDHA-1, qnrB, and qnrS, while another strain harbored blaCTX-M-15, qnrS and aac(6')-Ib-cr. The E. coli strain contained blaCTX-M-15, blaCMY-2, qnrS, and aac(6')-Ib-cr. Interestingly, the OXA-48 producers with a novel OmpK36 variant by a substitution of Gly to Asp in the L3 loop-borne PEFXG motif exhibited high-level resistance to ertapenem, imipenem, and meropenem. In contrast, the OXA-181 producer with non-porin-deficient background showed low-level resistance to ertapenem only. Both patients died because of either septic shock or pneumonia. This study showed the impact of OXA-48-like carbapenemases in porin-defective clinical isolate background, which may lead to serious therapeutic problems in the near future.

  2. Five carboxin-resistant mutants exhibited various responses to carboxin and related fungicides.

    PubMed

    Shima, Yoko; Ito, Yasuhiro; Hatabayashi, Hidemi; Koma, Akemi; Yabe, Kimiko

    2011-01-01

    Five carboxin-resistant mutants from Aspergillus oryzae were characterized by the sensitivities of their mycelial growth and succinate dehydrogenase (SDH) activity to carboxin and three related fungicides. Despite a significant resistance to carboxin, exhibited by all the mutants, their patterns of sensitivity to the other fungicides was distinct. This provides clues to the molecular interaction between SDH and these fungicides.

  3. 4-Isoxazolyl-1,4-dihydropyridines exhibit binding at the multidrug-resistance transporter.

    PubMed

    Hulubei, Victoria; Meikrantz, Scott B; Quincy, David A; Houle, Tina; McKenna, John I; Rogers, Mark E; Steiger, Scott; Natale, N R

    2012-11-15

    The 4-isoxazolyl-dihydropyridines (IDHPs) exhibit inhibition of the multidrug-resistance transporter (MDR-1), and exhibit an SAR distinct from their activity at voltage gated calcium channels (VGCC). Among the four most active IDHPs, three were branched at C-5 of the isoxazole, including the most active analog, 1k.

  4. Mature-stem expression of a silencing-resistant sucrose isomerase gene drives isomaltulose accumulation to high levels in sugarcane.

    PubMed

    Mudge, Stephen R; Basnayake, Shiromi W V; Moyle, Richard L; Osabe, Kenji; Graham, Michael W; Morgan, Terence E; Birch, Robert G

    2013-05-01

    Isomaltulose (IM) is a natural isomer of sucrose. It is widely approved as a food with properties including slower digestion, lower glycaemic index and low cariogenicity, which can benefit consumers. Availability is currently limited by the cost of fermentative conversion from sucrose. Transgenic sugarcane plants with developmentally-controlled expression of a silencing-resistant gene encoding a vacuole-targeted IM synthase were tested under field conditions typical of commercial sugarcane cultivation. High yields of IM were obtained, up to 483 mm or 81% of total sugars in whole-cane juice from plants aged 13 months. Using promoters from sugarcane to drive expression preferentially in the sugarcane stem, IM levels were consistent between stalks and stools within a transgenic line and across consecutive vegetative field generations of tested high-isomer lines. Germination and early growth of plants from setts were unaffected by IM accumulation, up to the tested level around 500 mm in flanking stem internodes. These are the highest yields ever achieved of value-added materials through plant metabolic engineering. The sugarcane stem promoters are promising for strategies to achieve even higher IM levels and for other applications in sugarcane molecular improvement. Silencing-resistant transgenes are critical to deliver the potential of these promoters in practical sugarcane improvement. At the IM levels now achieved in field-grown sugarcane, direct production of IM in plants is feasible at a cost approaching that of sucrose, which should make the benefits of IM affordable on a much wider scale.

  5. High-level fluoroquinolone resistant Salmonella enterica serovar Kentucky ST198 epidemic clone with IncA/C conjugative plasmid carrying bla(CTX-M-25) gene.

    PubMed

    Wasyl, Dariusz; Kern-Zdanowicz, Izabela; Domańska-Blicharz, Katarzyna; Zając, Magdalena; Hoszowski, Andrzej

    2015-01-30

    Multidrug resistant Salmonella Kentucky strains have been isolated from turkeys in Poland since 2009. Multiple mutations within chromosomal genes gyrA and parC were responsible for high-level ciprofloxacin resistance. One of the isolates was extended spectrum β-lactamase- (ESBL) positive: the strain 1643/2010 carried a conjugative 167,779 bps plasmid of IncA/C family. The sequence analysis revealed that it carried a blaCTX-M-25 gene and an integron with another β-lactamase encoding gene-blaOXA-21. This is the first known report of a CTX-M-25 encoding gene both in Poland and in Salmonella Kentucky world-wide, as well as in the IncA/C plasmid. Analysis of the integron showed a novel arrangement of gene cassettes-aacA4, aacC-A1 and blaOXA-21 where the latter might result from an intergeneric gene transfer. The study confirmed Salmonella Kentucky population isolated in Poland belongs to global epidemics of high level fluoroquinolone resistant clone ST198 that can carry rare β-lactamase genes.

  6. Abamectin is metabolized by CYP392A16, a cytochrome P450 associated with high levels of acaricide resistance in Tetranychus urticae.

    PubMed

    Riga, M; Tsakireli, D; Ilias, A; Morou, E; Myridakis, A; Stephanou, E G; Nauen, R; Dermauw, W; Van Leeuwen, T; Paine, M; Vontas, J

    2014-03-01

    Abamectin is one of the most important insecticides worldwide. It is used against major agricultural pests and insects of public health importance, as well as against endoparasites in animal health. Abamectin has been used successfully for the control of the spider mite Tetranychus urticae, a major agricultural pest with global distribution, an extremely diverse host range, and a remarkable ability to develop resistance against insecticides including abamectin. Target site resistance mutations may explain a large part of resistance, although genetic evidence and transcriptomic data indicated that additional mechanisms may also be implicated in the abamectin resistant phenotype. To investigate a functional link between cytochrome P450-mediated metabolism and abamectin resistance, we recombinantly expressed three cytochrome P450s (CYP392A16, CYP392D8 and CYP392D10) that have been associated with high levels of abamectin resistance in a resistant T. urticae strain isolated from Greece. CYP392A16 was expressed predominately in its P450 form however, both CYP392D8 and CYP392D10 were expressed predominately as P420, despite optimization efforts on expression conditions. CYP392A16 catalyses the hydroxylation of abamectin (Kcat=0.54 pmol/min/pmol P450; Km=45.9 μM), resulting in a substantially less toxic compound as confirmed by bioassays with the partially purified metabolite. However, CYP392A16 did not metabolize hexythiazox, clofentezine and bifenthrin, active ingredients that also showed reduced toxicity in the abamectin resistant strain. Among a number of fluorescent and luminescent substrates screened, Luciferin-ME EGE was preferentially metabolized by CYP392A16, and it may be a potential diagnostic probe for metabolic resistance detection and monitoring.

  7. Artemisinin-Resistant Plasmodium falciparum Parasites Exhibit Altered Patterns of Development in Infected Erythrocytes

    PubMed Central

    Hott, Amanda; Casandra, Debora; Sparks, Kansas N.; Morton, Lindsay C.; Castanares, Geocel-Grace; Rutter, Amanda

    2015-01-01

    Artemisinin derivatives are used in combination with other antimalarial drugs for treatment of multidrug-resistant malaria worldwide. Clinical resistance to artemisinin recently emerged in southeast Asia, yet in vitro phenotypes for discerning mechanism(s) of resistance remain elusive. Here, we describe novel phenotypic resistance traits expressed by artemisinin-resistant Plasmodium falciparum. The resistant parasites exhibit altered patterns of development that result in reduced exposure to drug at the most susceptible stage of development in erythrocytes (trophozoites) and increased exposure in the most resistant stage (rings). In addition, a novel in vitro delayed clearance assay (DCA) that assesses drug effects on asexual stages was found to correlate with parasite clearance half-life in vivo as well as with mutations in the Kelch domain gene associated with resistance (Pf3D7_1343700). Importantly, all of the resistance phenotypes were stable in cloned parasites for more than 2 years without drug pressure. The results demonstrate artemisinin-resistant P. falciparum has evolved a novel mechanism of phenotypic resistance to artemisinin drugs linked to abnormal cell cycle regulation. These results offer insights into a novel mechanism of drug resistance in P. falciparum and new tools for monitoring the spread of artemisinin resistance. PMID:25779582

  8. Combined expression of multidrug resistance protein (MRP) and glutathione S-transferase P1-1 (GSTP1-1) in MCF7 cells and high level resistance to the cytotoxicities of ethacrynic acid but not oxazaphosphorines or cisplatin.

    PubMed

    Morrow, C S; Smitherman, P K; Townsend, A J

    1998-10-15

    We tested the hypothesis that combined increased expression of human glutathione S-transferase P1-1 (GSTP1-1), an enzyme that catalyzes the conjugation with glutathione of several toxic electrophiles, and the glutathione-conjugate efflux pump, multidrug resistance protein (MRP), confers high level resistance to the cytotoxicities of anticancer and other drugs. To accomplish this, we developed MCF7 breast carcinoma cell derivatives that express high levels of GSTP1-1 and MRP, alone and in combination. Parental MCF7 cells, which express no GSTP1-1 and negligible MRP, served as control cells. We found that either MRP or GSTP1-1 alone conferred significant resistance to ethacrynic acid cytotoxicity. Moreover, combined expression of GSTP1-1 and MRP conferred a high level of resistance to ethacrynic acid that was greater than resistance conferred by either protein alone. Increased MRP was also associated with modest resistance to the oxazaphosphorine compounds mafosfamide, 4-hydroxycyclophosphamide, and 4-hydroperoxycyclophosphamide. However, coordinated expression of GSTP1-1 with MRP failed to augment this modest resistance. Similarly, GSTP1-1 had no effect on the sensitivities to cisplatin of MCF7 cells regardless of MRP expression. These results establish that coordinated expression of MRP and GSTP1-1 can confer high level resistance to the cytotoxicities of some drugs, including ethacrynic acid, but that such resistance is variable and does not apply to all toxic drugs that can potentially form glutathione conjugates in either spontaneous or GSTP1-1-catalyzed reactions.

  9. High-level aminoglycoside resistance in Enterococcus faecalis and Enterococcus faecium causing invasive infection: Twelve-year surveillance in the Minami Ibaraki Area.

    PubMed

    Osuka, Hanako; Nakajima, Jun; Oishi, Tsuyoshi; Funayama, Yasunori; Ebihara, Tsugio; Ishikawa, Hiroichi; Saito, Kazuto; Koganemaru, Hiroshi; Hitomi, Shigemi

    2016-01-01

    We examined prevalence of high-level aminoglycoside resistance (HLAR) in Enterococcus faecalis and Enterococcus faecium causing invasive infection in the Minami Ibaraki Area. Ten strains of both species each, recovered from the blood or the cerebrospinal fluid between 2003 and 2014, were randomly selected every year. High-level resistance to gentamicin (HLR-GM) and streptomycin (HLR-SM) was detected in 34% (41 of 120 strains) and 18% (21) of E. faecalis and 9% (11) and 39% (48) of E. faecium, respectively. In comparisons of the proportions among three four-year periods, HLR-SM among E. faecium was significantly lower in the 2011-2014 period. All strains with HLR-GM were positive for the aac(6')-Ie-aph(2″)-Ia gene. The ant(6')-Ia gene was detected in all with HLR-SM except for one E. faecalis strain. The present study showed that prevalence of HLR-GM among E. faecalis and E. faecium causing invasive infection in this area was nearly equivalent to that described in previous studies in Japan and that proportions of strains with HLAR did not vary during the study period except for that of HLR-SM among E. faecium.

  10. Rapid and Sensitive Oligonucleotide Ligation Assay for Detection of Mutations in Human Immunodeficiency Virus Type 1 Associated with High-Level Resistance to Protease Inhibitors

    PubMed Central

    Beck, Ingrid A.; Mahalanabis, Madhumita; Pepper, Gregory; Wright, Amy; Hamilton, Shannon; Langston, Erika; Frenkel, Lisa M.

    2002-01-01

    A sensitive, specific, and high-throughput oligonucleotide ligation assay (OLA) for the detection of genotypic human immunodeficiency virus type 1 (HIV-1) resistance to Food and Drug Administration-approved protease inhibitors was developed and evaluated. This ligation-based assay uses differentially modified oligonucleotides specific for wild-type or mutant sequences, allowing sensitive and simple detection of both genotypes in a single well of a microtiter plate. Oligonucleotides were designed to detect primary mutations associated with high-level resistance to amprenavir, nelfinavir, indinavir, ritonavir, saquinavir, and lopinavir, including amino acid substitutions D30N, I50V, V82A/S/T, I84V, N88D, and L90M. Plasma HIV-1 RNA from 54 infected patients was amplified by reverse transcription-PCR and sequenced by using dideoxynucleotide chain terminators for evaluation of mutations associated with drug resistance. These same amplicons were genotyped by the OLA at positions 30, 50, 82, 88, 84, and 90 for a total of 312 codons. The sensitivity of detection of drug-resistant genotypes was 96.7% (87 of 90 mutant codons) in the OLA compared to 92.2% (83 of 90) in consensus sequencing, presumably due to the increased sensitivity of the OLA. The OLA detected genetic subpopulations more often than sequencing, detecting 30 mixtures of mutant and wild-type sequences and two mixtures of drug-resistant sequences compared to 15 detected by DNA sequencing. Reproducible and semiquantitative detection of the mutant and the wild-type genomes by the OLA was observed by analysis of wild-type and mutant plasmid mixtures containing as little as 5% of either genotype in a background of the opposite genome. This rapid, simple, economical, and highly sensitive assay provides a practical alternative to dideoxy sequencing for genotypic evaluation of HIV-1 resistance to antiretrovirals. PMID:11923366

  11. RmtC introduces G1405 methylation in 16S rRNA and confers high-level aminoglycoside resistance on Gram-positive microorganisms.

    PubMed

    Wachino, Jun-Ichi; Shibayama, Keigo; Kimura, Kouji; Yamane, Kunikazu; Suzuki, Satowa; Arakawa, Yoshichika

    2010-10-01

    Seven plasmid-mediated 16S rRNA methyltransferases (MTases), RmtA, RmtB, RmtC, RmtD, RmtE, ArmA, and NpmA, conferring aminoglycoside resistance have so far been found in Gram-negative pathogenic microorganisms. In the present study, by performing an RNase protection assay, primer extension, and HPLC, we confirmed that RmtC indeed methylates at the N7 position of nucleotide G1405 in 16S rRNA as found in ArmA and RmtB. RmtC has an MTase activity specific for the bacterial 30S ribosomal subunit consisting of 16S rRNA and several ribosomal proteins, but not for the naked 16S rRNA, as seen in ArmA, RmtB, and NpmA. All seven 16S rRNA MTases have been found exclusively in Gram-negative bacilli to date, and no plasmid-mediated 16S rRNA MTase has been reported in Gram-positive pathogenic microorganisms. Thus, we checked whether or not the RmtC could function in Gram-positive bacilli, and found that RmtC could indeed confer high-level resistance to gentamicin and kanamycin in Bacillus subtilis and Staphylococcus aureus. 16S rRNA MTases seemed to be functional to some extent in any bacterial species, regardless of the provenance of the 16S rRNA MTase gene responsible for aminoglycoside resistance.

  12. FECAL SOURCE TRACKING BY ANTIBIOTIC RESISTANCE ANALYSIS ON A WATERSHED EXHIBITING LOW RESISTANCE

    EPA Science Inventory

    The ongoing development of microbial source tracking has made it possible to identify contamination sources with varying accuracy, depending on the method used. The purpose of this study was done to test the efficiency of the antibiotic resistance analysis (ARA) method under low ...

  13. Fitness Costs and Stability of a High-Level Ciprofloxacin Resistance Phenotype in Salmonella enterica Serotype Enteritidis: Reduced Infectivity Associated with Decreased Expression of Salmonella Pathogenicity Island 1 Genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fitness costs associated with high-level fluoroquinolone resistance were examined in phenotypically and genotypically characterized ciprofloxacin-resistant Salmonella Enteritidis mutants (104-cip and 5408-cip, MIC > 32 µg/ml). The stability of the fluoroquinolone resistance phenotype in both mut...

  14. Catalytic properties of an organic solvent-resistant tyrosinase from Streptomyces sp. REN-21 and its high-level production in E. coli.

    PubMed

    Ito, Masaaki; Inouye, Kuniyo

    2005-10-01

    An organic solvent-resistant tyrosinase (OSRT) from Streptomyces sp. REN-21 is a unique enzyme showing high activity in the presence of organic solvents. The OSRT-catalyzed oxidation of monophenols such as tyrosine-containing peptides and proteins was examined. The catalytic properties of OSRT were compared with those of mushroom tyrosinase. OSRT was shown to oxidize Gly-l-Tyr most effectively among four peptide substrates tested. On the other hand, mushroom tyrosinase showed the highest activity toward l-Tyr-Gly under the condition of 1 mM substrate. OSRT oxidized several proteins, including casein and hemoglobin, with relatively higher activity compared with mushroom tyrosinase under the condition of 1% (w/v) substrate. Thus, it was clarified that the catalytic properties of OSRT toward tyrosine-containing peptides and proteins are different from those of mushroom tyrosinase under these conditions. The OSRT-encoding gene operon was cloned, and found to consist of two genes, designated ORF-OSRT and ORF-393. The former encodes apo-OSRT, and the latter encodes the putative activator protein of apo-OSRT. A binuclear copper-binding site (type-3 copper site) characteristic of tyrosinases is contained in the deduced amino acid sequence for apo-OSRT. A high-level production system for the OSRT was constructed using pET20b(+) and Escherichia coli BL21(DE3)pLysS. Approximately 54 mg of active OSRT was synthesized in a 1-liter broth culture by this system. The properties of the recombinant OSRT were similar to those of the wild-type enzyme. In conclusion, we succeeded in constructing a high-level production system for OSRT.

  15. Epitaxial electrodeposition of metal oxide films and superlattices which exhibit resistance switching

    NASA Astrophysics Data System (ADS)

    Gudavarthy, Rakesh Vathsal

    This dissertation presents an investigation of the electrodeposition of metal oxide films and superlattices on conducting polycrystalline and single crystal substrates. In the first part of the study, electrodeposition of magnetite (Fe3O4) films and superlattices in the magnetite/zinc ferrite system which exhibit resistance switching is studied. Paper I reports the electrodeposition of superlattices in the magnetite/zinc ferrite system and shows that only superlattices exhibit multi state resistance switching. In paper II, simple polycrystalline magnetite films electrodeposited on stainless steel crystals exhibit multistate resistance switching which can be tuned by controlling the composition of the films. Paper III describes the epitaxial electrodeposition of Fe3O4films on Ni(111) substrates. In the second part, electrodeposited epitaxial films of CuO onto achiral Cu single crystals using chiral precursors are studied. Paper IV describes chiral electrodeposition of CuO from copper(II) complexes of malic acid on Cu single crystals. X-ray pole figures in conjunction with stereographic projections are used to determine the absolute configuration of the films. X-ray crystal structures of copper(II) malate crystals are analyzed to understand the mechanism of chiral electrodeposition.

  16. Transgenic Citrus Expressing an Arabidopsis NPR1 Gene Exhibit Enhanced Resistance against Huanglongbing (HLB; Citrus Greening)

    PubMed Central

    Dutt, Manjul; Barthe, Gary; Irey, Michael; Grosser, Jude

    2015-01-01

    Commercial sweet orange cultivars lack resistance to Huanglongbing (HLB), a serious phloem limited bacterial disease that is usually fatal. In order to develop sustained disease resistance to HLB, transgenic sweet orange cultivars ‘Hamlin’ and ‘Valencia’ expressing an Arabidopsis thaliana NPR1 gene under the control of a constitutive CaMV 35S promoter or a phloem specific Arabidopsis SUC2 (AtSUC2) promoter were produced. Overexpression of AtNPR1 resulted in trees with normal phenotypes that exhibited enhanced resistance to HLB. Phloem specific expression of NPR1 was equally effective for enhancing disease resistance. Transgenic trees exhibited reduced diseased severity and a few lines remained disease-free even after 36 months of planting in a high-disease pressure field site. Expression of the NPR1 gene induced expression of several native genes involved in the plant defense signaling pathways. The AtNPR1 gene being plant derived can serve as a component for the development of an all plant T-DNA derived consumer friendly GM tree. PMID:26398891

  17. Comparative study of bacteremias caused by Enterococcus spp. with and without high-level resistance to gentamicin. The Grupo Andaluz para el estudio de las Enfermedades Infecciosas.

    PubMed

    Caballero-Granado, F J; Cisneros, J M; Luque, R; Torres-Tortosa, M; Gamboa, F; Díez, F; Villanueva, J L; Pérez-Cano, R; Pasquau, J; Merino, D; Menchero, A; Mora, D; López-Ruz, M A; Vergara, A

    1998-02-01

    A prospective, multicenter study was carried out over a period of 10 months. All patients with clinically significant bacteremia caused by Enterococcus spp. were included. The epidemiological, microbiological, clinical, and prognostic features and the relationship of these features to the presence of high-level resistance to gentamicin (HLRG) were studied. Ninety-three patients with enterococcal bacteremia were included, and 31 of these cases were caused by HLRG (33%). The multivariate analysis selected chronic renal failure, intensive care unit stay, previous use of antimicrobial agents, and Enterococcus faecalis species as the independent risk factors that influenced the development of HLRG. The strains with HLRG showed lower levels of susceptibility to penicillin and ciprofloxacin. Clinical features (except for chronic renal failure) were similar in both groups of patients. HLRG did not influence the prognosis for patients with enterococcal bacteremia in terms of either the crude mortality rate (29% for patients with bacteremia caused by enterococci with HLRG and 28% for patients not infected with strains with HLRG) or the hospital stay after the acquisition of enterococcal bacteremia. Hemodynamic compromise, inappropriate antimicrobial therapy, and mechanical ventilation were revealed in the multivariate analysis to be the independent risk factors for mortality. Prolonged hospitalization was associated with the nosocomial acquisition of bacteremia and polymicrobial infections.

  18. Exposing a β-Lactamase “Twist”: the Mechanistic Basis for the High Level of Ceftazidime Resistance in the C69F Variant of the Burkholderia pseudomallei PenI β-Lactamase

    PubMed Central

    Becka, Scott A.; Taracila, Magdalena A.; Winkler, Marisa L.; Gatta, Julian A.; Rholl, Drew A.; Schweizer, Herbert P.

    2015-01-01

    Around the world, Burkholderia spp. are emerging as pathogens highly resistant to β-lactam antibiotics, especially ceftazidime. Clinical variants of Burkholderia pseudomallei possessing the class A β-lactamase PenI with substitutions at positions C69 and P167 are known to demonstrate ceftazidime resistance. However, the biochemical basis for ceftazidime resistance in class A β-lactamases in B. pseudomallei is largely undefined. Here, we performed site saturation mutagenesis of the C69 position and investigated the kinetic properties of the C69F variant of PenI from B. pseudomallei that results in a high level of ceftazidime resistance (2 to 64 mg/liter) when expressed in Escherichia coli. Surprisingly, quantitative immunoblotting showed that the steady-state protein levels of the C69F variant β-lactamase were ∼4-fold lower than those of wild-type PenI (0.76 fg of protein/cell versus 4.1 fg of protein/cell, respectively). However, growth in the presence of ceftazidime increases the relative amount of the C69F variant to greater than wild-type PenI levels. The C69F variant exhibits a branched kinetic mechanism for ceftazidime hydrolysis, suggesting there are two different conformations of the enzyme. When incubated with an anti-PenI antibody, one conformation of the C69F variant rapidly hydrolyzes ceftazidime and most likely contributes to the higher levels of ceftazidime resistance observed in cell-based assays. Molecular dynamics simulations suggest that the electrostatic characteristics of the oxyanion hole are altered in the C69F variant. When ceftazidime was positioned in the active site, the C69F variant is predicted to form a greater number of hydrogen-bonding interactions than PenI with ceftazidime. In conclusion, we propose “a new twist” for enhanced ceftazidime resistance mediated by the C69F variant of the PenI β-lactamase based on conformational changes in the C69F variant. Our findings explain the biochemical basis of ceftazidime resistance in

  19. Cognitively impaired elderly exhibit insulin resistance and no memory improvement with infused insulin.

    PubMed

    Morris, Jill K; Vidoni, Eric D; Mahnken, Jonathan D; Montgomery, Robert N; Johnson, David K; Thyfault, John P; Burns, Jeffrey M

    2016-03-01

    Insulin resistance is a risk factor for Alzheimer's disease (AD), although its role in AD etiology is unclear. We assessed insulin resistance using fasting and insulin-stimulated measures in 51 elderly subjects with no dementia (ND; n = 37) and with cognitive impairment (CI; n = 14). CI subjects exhibited either mild CI or AD. Fasting insulin resistance was measured using the homeostatic model assessment of insulin resistance (HOMA-IR). Insulin-stimulated glucose disposal was assessed using the hyperinsulinemic-euglycemic clamp to calculate glucose disposal rate into lean mass, the primary site of insulin-stimulated glucose disposal. Because insulin crosses the blood-brain barrier, we also assessed whether insulin infusion would improve verbal episodic memory compared to baseline. Different but equivalent versions of cognitive tests were administered in counterbalanced order in the basal and insulin-stimulated state. Groups did not differ in age or body mass index. Cognitively impaired subjects exhibited greater insulin resistance as measured at fasting (HOMA-IR; ND: 1.09 [1.1] vs. CI: 2.01 [2.3], p = 0.028) and during the hyperinsulinemic clamp (glucose disposal rate into lean mass; ND: 9.9 (4.5) vs. AD 7.2 (3.2), p = 0.040). Cognitively impaired subjects also exhibited higher fasting insulin compared to ND subjects, (CI: 8.7 [7.8] vs. ND: 4.2 [3.8] μU/mL; p = 0.023) and higher fasting amylin (CI: 24.1 [39.1] vs. 8.37 [14.2]; p = 0.050) with no difference in fasting glucose. Insulin infusion elicited a detrimental effect on one test of verbal episodic memory (Free and Cued Selective Reminding Test) in both groups (p < 0.0001) and no change in performance on an additional task (delayed logical memory). In this study, although insulin resistance was observed in cognitively impaired subjects compared to ND controls, insulin infusion did not improve memory. Furthermore, a significant correlation between HOMA-IR and glucose disposal rate was present only in ND

  20. High-temperature corrosion-resistant iron-aluminide (FeAl) alloys exhibiting improved weldability

    DOEpatents

    Maziasz, Philip J.; Goodwin, Gene M.; Liu, Chain T.

    1996-01-01

    This invention relates to improved corrosion-resistant iron-aluminide intermetallic alloys. The alloys of this invention comprise, in atomic percent, from about 30% to about 40% aluminum alloyed with from about 0.1% to about 0.5% carbon, no more than about 0.04% boron such that the atomic weight ratio of boron to carbon in the alloy is in the range of from about 0.01:1 to about 0.08:1, from about 0.01 to about 3.5% of one or more transition metals selected from Group IVB, VB, and VIB elements and the balance iron wherein the alloy exhibits improved resistance to hot cracking during welding.

  1. High-temperature corrosion-resistant iron-aluminide (FeAl) alloys exhibiting improved weldability

    DOEpatents

    Maziasz, P.J.; Goodwin, G.M.; Liu, C.T.

    1996-08-13

    This invention relates to improved corrosion-resistant iron-aluminide intermetallic alloys. The alloys of this invention comprise, in atomic percent, from about 30% to about 40% aluminum alloyed with from about 0.1% to about 0.5% carbon, no more than about 0.04% boron such that the atomic weight ratio of boron to carbon in the alloy is in the range of from about 0.01:1 to about 0.08:1, from about 0.01 to about 3.5% of one or more transition metals selected from Group IVB, VB, and VIB elements and the balance iron wherein the alloy exhibits improved resistance to hot cracking during welding. 13 figs.

  2. High-level hemicellulosic arabinose predominately affects lignocellulose crystallinity for genetically enhancing both plant lodging resistance and biomass enzymatic digestibility in rice mutants.

    PubMed

    Li, Fengcheng; Zhang, Mingliang; Guo, Kai; Hu, Zhen; Zhang, Ran; Feng, Yongqing; Yi, Xiaoyan; Zou, Weihua; Wang, Lingqiang; Wu, Changyin; Tian, Jinshan; Lu, Tiegang; Xie, Guosheng; Peng, Liangcai

    2015-05-01

    Rice is a major food crop with enormous biomass residue for biofuels. As plant cell wall recalcitrance basically decides a costly biomass process, genetic modification of plant cell walls has been regarded as a promising solution. However, due to structural complexity and functional diversity of plant cell walls, it becomes essential to identify the key factors of cell wall modifications that could not much alter plant growth, but cause an enhancement in biomass enzymatic digestibility. To address this issue, we performed systems biology analyses of a total of 36 distinct cell wall mutants of rice. As a result, cellulose crystallinity (CrI) was examined to be the key factor that negatively determines either the biomass enzymatic saccharification upon various chemical pretreatments or the plant lodging resistance, an integrated agronomic trait in plant growth and grain production. Notably, hemicellulosic arabinose (Ara) was detected to be the major factor that negatively affects cellulose CrI probably through its interlinking with β-1,4-glucans. In addition, lignin and G monomer also exhibited the positive impact on biomass digestion and lodging resistance. Further characterization of two elite mutants, Osfc17 and Osfc30, showing normal plant growth and high biomass enzymatic digestion in situ and in vitro, revealed the multiple GH9B candidate genes for reducing cellulose CrI and XAT genes for increasing hemicellulosic Ara level. Hence, the results have suggested the potential cell wall modifications for enhancing both biomass enzymatic digestibility and plant lodging resistance by synchronically overexpressing GH9B and XAT genes in rice.

  3. Grizzly bears exhibit augmented insulin sensitivity while obese prior to a reversible insulin resistance during hibernation.

    PubMed

    Nelson, O Lynne; Jansen, Heiko T; Galbreath, Elizabeth; Morgenstern, Kurt; Gehring, Jamie Lauren; Rigano, Kimberly Scott; Lee, Jae; Gong, Jianhua; Shaywitz, Adam J; Vella, Chantal A; Robbins, Charles T; Corbit, Kevin C

    2014-08-05

    The confluence of obesity and diabetes as a worldwide epidemic necessitates the discovery of new therapies. Success in this endeavor requires translatable preclinical studies, which traditionally employ rodent models. As an alternative approach, we explored hibernation where obesity is a natural adaptation to survive months of fasting. Here we report that grizzly bears exhibit seasonal tripartite insulin responsiveness such that obese animals augment insulin sensitivity but only weeks later enter hibernation-specific insulin resistance (IR) and subsequently reinitiate responsiveness upon awakening. Preparation for hibernation is characterized by adiposity coupled to increased insulin sensitivity via modified PTEN/AKT signaling specifically in adipose tissue, suggesting a state of "healthy" obesity analogous to humans with PTEN haploinsufficiency. Collectively, we show that bears reversibly cope with homeostatic perturbations considered detrimental to humans and describe a mechanism whereby IR functions not as a late-stage metabolic adaptation to obesity, but rather a gatekeeper of the fed-fasting transition.

  4. A cleavage-resistant urokinase plasminogen activator receptor exhibits dysregulated cell-surface clearance.

    PubMed

    Nieves, Evelyn C; Manchanda, Naveen

    2010-04-23

    Urokinase plasminogen activator receptor (u-PAR) binds urokinase plasminogen activator (u-PA) and participates in plasminogen activation in addition to modulating several cellular processes such as adhesion, proliferation, and migration. u-PAR is susceptible to proteolysis by its cognate ligand and several other proteases. To elucidate the biological significance of receptor cleavage by u-PA, we engineered and expressed a two-chain urokinase plasminogen activator (tcu-PA) cleavage-resistant u-PAR (cr-u-PAR). This mutated receptor was similar to wild-type u-PAR in binding u-PA and initiating plasminogen activation. However, cr-u-PAR exhibited accelerated internalization and resurfacing due to direct association with the endocytic receptor alpha(2)-macroglobulin receptor/low density lipoprotein receptor-related protein in the absence of the enzyme x inhibitor complex of tcu-PA and plasminogen activator inhibitor-1 (tcu-PA.PAI-1). cr-u-PAR-expressing cells had enhanced migration compared with wild-type u-PAR-expressing cells, and cr-u-PAR was less sensitive to chymotrypsin cleavage as compared with wt u-PAR. Our studies suggest that these mutations in the linker region result in a rearrangement within the cr-u-PAR structure that makes it resemble its ligand-bound form. This constitutively active variant may mimic highly glycosylated cleavage-resistant u-PAR expressed in certain highly malignant cancer-cells.

  5. Bulbispermine: a crinine-type Amaryllidaceae alkaloid exhibiting cytostatic activity toward apoptosis-resistant glioma cells.

    PubMed

    Luchetti, Giovanni; Johnston, Robert; Mathieu, Véronique; Lefranc, Florence; Hayden, Kathryn; Andolfi, Anna; Lamoral-Theys, Delphine; Reisenauer, Mary R; Champion, Cody; Pelly, Stephen C; van Otterlo, Willem A L; Magedov, Igor V; Kiss, Robert; Evidente, Antonio; Rogelj, Snezna; Kornienko, Alexander

    2012-05-01

    The Amaryllidaceae alkaloid bulbispermine was derivatized to produce a small group of synthetic analogues. These, together with bulbispermine's natural crinine-type congeners, were evaluated in vitro against a panel of cancer cell lines with various levels of resistance to pro-apoptotic stimuli. Bulbispermine, haemanthamine, and haemanthidine showed the most potent antiproliferative activities as determined by the MTT colorimetric assay. Among the synthetic bulbispermine analogues, only the C1,C2-dicarbamate derivative exhibited notable growth inhibitory properties. All active compounds were found not to discriminate between the cancer cell lines based on the apoptosis sensitivity criterion; they displayed similar potencies in both cell types, indicating that the induction of apoptosis is not the primary mechanism responsible for antiproliferative activity in this series of compounds. It was also found that bulbispermine inhibits the proliferation of glioblastoma cells through cytostatic effects, possibly arising from rigidification of the actin cytoskeleton. These findings lead us to argue that crinine-type alkaloids are potentially useful drug leads for the treatment of apoptosis-resistant cancers and glioblastoma in particular.

  6. Bulbispermine: A Crinine-Type Amaryllidaceae Alkaloid Exhibiting Cytostatic Activity towards Apoptosis-Resistant Glioma Cells

    PubMed Central

    Luchetti, Giovanni; Johnston, Robert; Mathieu, Véronique; Lefranc, Florence; Hayden, Kathryn; Andolfi, Anna; Lamoral-Theys, Delphine; Reisenauer, Mary R.; Champion, Cody; Pelly, Stephen C.; van Otterlo, Willem A. L.; Magedov, Igor V.; Kiss, Robert; Evidente, Antonio; Rogelj, Snezna; Kornienko, Alexander

    2012-01-01

    The Amaryllidaceae alkaloid bulbispermine was derivatized to produce a small group of synthetic analogues. These, together with bulbispermine’s natural crinine-type congeners, were evaluated in vitro against a panel of cancer cell lines with various levels of resistance to proapoptotic stimuli. Bulbispermine, haemanthamine and haemanthidine showed the most potent antiproliferative activities as determined by the MTT colorimetric assay. Among the synthetic bulbispermine analogues, only the C1,C2-dicarbamate derivative exhibited noteworthy growth inhibitory properties. All active compounds were found not to discriminate between the cancer cell lines based on the apoptosis sensitivity criterion and displayed comparable potencies in both cell types, indicating that apoptosis induction is not the primary mechanism responsible for antiproliferative activity in this series of compounds. It was also found that bulbispermine inhibits the proliferation of glioblastoma cells through cytostatic effects, possibly arising from the rigidification of the actin cytoskeleton. These findings lead us to argue that crinine-type alkaloids are potentially useful drug leads for the treatment of apoptosis resistant cancers and glioblastoma in particular. PMID:22389235

  7. ANAEROBIC RESISTANCE TO HIGH LEVELS OF CADMIUM AND OTHER TOXIC METALS IN A FACULTATIVE ANAEROBE ISOLATED FROM PRISTINE SALT MARSH SEDIMENTS

    SciTech Connect

    SHARMA,P.K.; VAIRAVAMURTHY,A.; KIELECZAWA,J.

    1999-06-20

    The authors have isolated many Cd (II) resistant bacterial strains from relatively pristine sediments collected from salt marshes in Shelter Island, New York. Detailed studies are being performed on one isolate, strain Cd-1. Strain Cd-1 is metabolically diverse, halotolerant, Gram-negative, facultative anaerobe. It can resist high amounts of Cd (II), Cr (VI), As (V), Se (IV), Co (II), Pb (II), or Zn (II) under defined anaerobic conditions. With pyruvate as the energy source, Cd-1 can grow well at examined Cd (II) concentrations ranging up to 15 mM. It can resist Cd (II) with or without marine level NaCl concentration, under acidic or neutral conditions. It can resist Cd (II) under aerobic conditions as well. These features are novel for a heavy metal resistant bacterium.

  8. High-level ciprofloxacin resistance from point mutations in gyrA and parC confined to global hospital-adapted clonal lineage CC17 of Enterococcus faecium.

    PubMed

    Leavis, Helen L; Willems, Rob J L; Top, Janetta; Bonten, Marc J M

    2006-03-01

    To substantiate a common genetic background of ciprofloxacin-resistant Enterococcus faecium, 32 ciprofloxacin-resistant (Cip(r)) and 31 ciprofloxacin-susceptible (Cip(s)) isolates from outbreaks, clinical infections, surveillances, and animals from 10 different countries were genotyped by multilocus sequence typing. Additionally, susceptibilities to ampicillin and vancomycin and the presence of esp were determined and the quinolone resistance-determining regions of parC, gyrA, parB, and gyrE were sequenced. High-level Cip(r) (MIC > or = 64 microg/ml) due to point mutations in the quinolone resistance-determining region was unique to a distinct hospital-adapted genetic complex in E. faecium, previously designated CC17. Low-level Cip(r) (MIC = 4 microg/ml) in non-CC17 strains is not attributable to point mutations in any subunit of the topoisomerase genes, and the mechanism of resistance remains unclear. Acquisition of mutations in parC and gyrA, leading to high-level Cip(r), is, in addition to ampicillin resistance and the presence of a putative pathogenicity island, another cumulative step in hospital adaptation of CC17.

  9. Transgenic banana plants expressing small interfering RNAs targeted against viral replication initiation gene display high-level resistance to banana bunchy top virus infection.

    PubMed

    Shekhawat, Upendra K S; Ganapathi, Thumballi R; Hadapad, Ashok B

    2012-08-01

    The banana aphid-transmitted Banana bunchy top virus (BBTV) is the most destructive viral pathogen of bananas and plantains worldwide. Lack of natural sources of resistance to BBTV has necessitated the exploitation of proven transgenic technologies for obtaining BBTV-resistant banana cultivars. In this study, we have explored the concept of using intron-hairpin-RNA (ihpRNA) transcripts corresponding to viral master replication initiation protein (Rep) to generate BBTV-resistant transgenic banana plants. Two ihpRNA constructs namely ihpRNA-Rep and ihpRNA-ProRep generated using Rep full coding sequence or Rep partial coding sequence together with its 5' upstream regulatory region, respectively, and castor bean catalase intron were successfully transformed into banana embryogenic cells. ihpRNA-Rep- and ihpRNA-ProRep-derived transgenic banana plants, selected based on preliminary screening for efficient reporter gene expression, were completely resistant to BBTV infection as indicated by the absence of disease symptoms after 6 months of viruliferous aphid inoculation. The resistance to BBTV infection was also evident by the inability to detect cDNAs coding for viral coat protein, movement protein and Rep protein by RT-PCR from inoculated transgenic leaf extracts. Southern analysis of the two groups of transgenics showed that ihpRNA transgene was stably integrated into the banana genome. The detection of small interfering RNAs (siRNAs) derived from the ihpRNA transgene sequence in transformed BBTV-resistant plants positively established RNA interference as the mechanism underlying the observed resistance to BBTV. Efficient screening of optimal transformants in this vegetatively propagated non-segregating fruit crop ensured that all the transgenic plants assayed were resistant to BBTV infection.

  10. Successful low-dose leflunomide treatment for ganciclovir-resistant cytomegalovirus infection with high-level antigenemia in a kidney transplant: A case report and literature review.

    PubMed

    Morita, Shinya; Shinoda, Kazunobu; Tamaki, Satoshi; Kono, Hidaka; Asanuma, Hiroshi; Nakagawa, Ken; Oya, Mototsugu

    2016-09-01

    Ganciclovir-resistant cytomegalovirus infection is sometimes life-threatening for organ transplant recipients. Foscarnet is an alternative, although it may potentially worsen the preexistent impaired renal function. Here we report the case of a successful low-dose leflunomide treatment in a kidney transplant recipient with very high viral replication, who underwent kidney transplantation 10 years before. Administering 10mg leflunomide daily for 5 months without a loading dose completely cleared the ganciclovir-resistant cytomegalovirus strains.

  11. Important Mutations Contributing to High-Level Penicillin Resistance in Taiwan(19F)-14, Taiwan(23F)-15, and Spain(23F)-1 of Streptococcus pneumoniae Isolated from Taiwan.

    PubMed

    Liu, Esther Yip-Mei; Chang, Jen-Chang; Lin, Jung-Chung; Chang, Feng-Yee; Fung, Chang-Phone

    2016-12-01

    Penicillin-resistant Streptococcus pneumoniae is a serious concern worldwide. In this study, we analyzed the cause of β-lactam resistance in pandemic multidrug-resistant clones. A total of 41 penicillin-nonsusceptible clinical isolates were collected from 1996 to 2012. Sero- and molecular typing confirmed that these isolates were clonal types of Taiwan(19F)-14, Taiwan(23F)-15, and Spain(23F)-1. Sero-switching was found in four isolates. All isolates were multidrug resistant. Sequencing analysis of the penicillin binding proteins (PBPs) was performed on PBP1a, 2b, and 2x, and a large number of mutations were identified in comparing to clinical penicillin-susceptible isolates and the recipient strain R6 used for homologous recombination. The T451A substitution was the key amino acid in PBP2b that contributed to penicillin resistance. T338A in PBP2x played a role in resistance and reached the highest level of resistance when combined with other mutations in PBP2x. High-level penicillin resistance could not be obtained without the combination of mutations in PBP1a with PBP2b and 2x. The amino acid substitutions in PBP1a, 2b, and 2x were the crucial factors for β-lactam resistance.

  12. High levels of extended-spectrum beta-lactamases in a major teaching hospital in Ghana: the need for regular monitoring and evaluation of antibiotic resistance.

    PubMed

    Obeng-Nkrumah, Noah; Twum-Danso, Kingsley; Krogfelt, Karen A; Newman, Mercy J

    2013-11-01

    Infections with bacteria producing extended-spectrum beta-lactamases (ESBLs) are increasing across Africa. This study reports on ESBL-producing Enterobacteriaceae as significant causes of infections and antibiotic resistance at Korle-Bu Teaching Hospital in Accra, Ghana. Of 300 isolates examined, 49.3% produced ESBLs. The prevalence of ESBLs was significantly high among isolates from neonates (28 of 43, 65.1%; relative risk = 1.62, 95% confidence interval = 1.33-2.13, P = 0.002) and adult patients > 65 years of age (36 of 51, 70.5%; relative risk = 1.89, 95% confidence interval = 1.41-2.40, P = 0.001). A marked increase in minimum inhibitory concentrations of ESBL-positive species was noticed compared with those for the other strains. Using these concentrations, we found that 26 (17%) ESBL producers were resistant to two or more antibiotics (aminoglycosides, fluoroquinolones, sulfonamide, and carbapenems) whereas 5 (3.2%) non-ESBL producers were multidrug resistant. Regular ESBL detection and evaluation of antibiotic resistance may help reduce the spread of ESBLs and antibiotic resistance in Ghana.

  13. Characterization and growth of epitaxial layers of Gs exhibiting high resistivity for ionic implantation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Either classical or low temperature epitaxial growth techniques can be used to control the deposition of buffer layers of GaAs on semiconducting substrates and to obtain the resistivity and purity desired. Techniques developed to study, as a function of thickness, the evolution of mobilities by photoHall, and the spectroscopy of shallow and deep centers by cathodoluminescence and current transients reveal one very pure layer of medium resistivity and high mobility, and another "dead layer" of elevated resistivity far from the surface. The highly resistive layer remains pure over several microns, which appears interesting for implantation.

  14. The efficacy of long-lasting nets with declining physical integrity may be compromised in areas with high levels of pyrethroid resistance

    PubMed Central

    2013-01-01

    Background Long-lasting insecticide-treated mosquito nets (LLINs) are a primary malaria prevention strategy in sub-Saharan Africa. However, emergence of insecticide resistance threatens the effectiveness of LLINs. Methods Cross-sectional surveys of LLINs were conducted in houses of seven and four villages in Gem and Bungoma Districts in western Kenya, respectively. Condition (number and area of holes in the nets), number and species of mosquitoes resting inside them, and insecticidal activity of nets were quantified. Mosquitoes collected inside nets were allowed to lay eggs and progeny tested for susceptibility to deltamethrin and permethrin, pyrethoids commonly deployed in LLINs in western Kenya. Results In Gem, 83.3% of nets were less than three years old and 32.4% had at least one hole of any size; while in Bungoma, 92% were less than three years old and 48% had at least one hole. No anopheline and five Culex spp. mosquitoes were found resting inside nets in Gem regardless of the number and size of holes, while 552 Anopheles gambiae s.l., five Anopheles funestus s.l. and 137 Culex spp. were in nets in Bungoma. The number of mosquitoes resting inside nets increased with hole areas >50 cm in Bungoma. In WHO resistance assays, f1 offspring of samples collected in nets in Bungoma were 94 and 65% resistant to deltamethrin and permethrin, respectively. Nets from Bungoma retained strong activity against a susceptible laboratory strain, but not against f1 offspring of field-collected An. gambiae s.s. All An. gambiae s.s. samples collected in nets were homozygous for the kdr genotype L1014S. Conclusions In areas with pyrethroid resistant vectors, LLINs with modest hole areas permit mosquito entry and feeding, providing little protection against the vectors. LLIN formulations develop large holes within three years of use, diminishing their presupposed lifetime effectiveness. PMID:24156715

  15. Cyt1Aa Protein of Bacillus thuringiensis Is Toxic to the Cottonwood Leaf Beetle, Chrysomela scripta, and Suppresses High Levels of Resistance to Cry3Aa

    PubMed Central

    Federici, Brian A.; Bauer, Leah S.

    1998-01-01

    The insecticidal activity of Bacillus thuringiensis is due primarily to Cry and Cyt proteins. Cry proteins are typically toxic to lepidopterous, coleopterous, or dipterous insects, whereas the known toxicity of Cyt proteins is limited to dipterans. We report here that a Cyt protein, Cyt1Aa, is also highly toxic to the cottonwood leaf beetle, Chrysomela scripta, with a median lethal concentration of 2.5 ng/mm2 of leaf surface for second-instar larvae. Additionally, we show that Cyt1Aa suppresses resistance to Cry3Aa greater than 5,000-fold in C. scripta, a level only partially overcome by Cry1Ba due to cross-resistance. Studies of the histopathology of C. scripta larvae treated with Cyt1Aa revealed disruption and sloughing of midgut epithelial cells, indicating that its mechanism of action against C. scripta is similar to that observed in mosquito and blackfly larvae. These novel properties suggest that Cyt proteins may have an even broader spectrum of activity against insects and, owing to their different mechanism of action in comparison to Cry proteins, might be useful in managing resistance to Cry3 and possibly other Cry toxins used in microbial insecticides and transgenic plants. PMID:9797292

  16. High Levels of Antibiotic Resistance Genes and Their Correlations with Bacterial Community and Mobile Genetic Elements in Pharmaceutical Wastewater Treatment Bioreactors

    PubMed Central

    Tao, Wenda; Zhang, Xu-Xiang; Zhao, Fuzheng; Huang, Kailong; Ma, Haijun; Wang, Zhu; Ye, Lin; Ren, Hongqiang

    2016-01-01

    To understand the diversity and abundance of antibiotic resistance genes (ARGs) in pharmaceutical wastewater treatment bioreactors, the ARGs in sludge from two full-scale pharmaceutical wastewater treatment plants (PWWTPs) were investigated and compared with sludge samples from three sewage treatment plants (STPs) using metagenomic approach. The results showed that the ARG abundances in PWWTP sludge ranged from 54.7 to 585.0 ppm, which were higher than those in STP sludge (27.2 to 86.4 ppm). Moreover, the diversity of ARGs in PWWTP aerobic sludge (153 subtypes) was higher than that in STP aerobic sludge (118 subtypes). In addition, it was found that the profiles of ARGs in PWWTP aerobic sludge were similar to those in STP aerobic sludge but different from those in PWWTP anaerobic sludge, suggesting that dissolve oxygen (DO) could be one of the important factors affecting the profiles of ARGs. In PWWTP aerobic sludge, aminoglycoside, sulfonamide and multidrug resistance genes were frequently detected. While, tetracycline, macrolide-lincosamide-streptogramin and polypeptide resistance genes were abundantly present in PWWTP anaerobic sludge. Furthermore, we investigated the microbial community and the correlation between microbial community and ARGs in PWWTP sludge. And, significant correlations between ARG types and seven bacterial genera were found. In addition, the mobile genetic elements (MGEs) were also examined and correlations between the ARGs and MGEs in PWWTP sludge were observed. Collectively, our results suggested that the microbial community and MGEs, which could be affected by DO, might be the main factors shaping the profiles of ARGs in PWWTP sludge. PMID:27294780

  17. A Novel Mechanism of High-Level, Broad-Spectrum Antibiotic Resistance Caused by a Single Base Pair Change in Neisseria gonorrhoeae

    DTIC Science & Technology

    2011-09-20

    originally isolated in the 1960s from a patient with an un- complicated cervical infection (13) and since used extensively by many researchers, exhibits...promoters (P). mtrR and mtrCDE are divergently transcribed on opposite strands. The locations of the mtr120 mutation and the mtrC-lacZ fusion start...bio.asm .org on S eptem ber 27, 2011 - P ublished by m bio.asm .org D ow nloaded from mtr120 mtrCF-lacZ fusion showed significantly higher

  18. Intraspecific variation in aphid resistance and constitutive phenolics exhibited by the wild blueberry Vaccinium darrowi.

    PubMed

    Ranger, C M; Singh, A P; Johnson-Cicalese, J; Polavarapu, S; Vorsa, N

    2007-04-01

    Illinoia pepperi (MacGillivray) infests cultivated highbush blueberries, Vaccinium corymbosum L., in the Northeastern United States. Allopatric resistance to I. pepperi was examined in Vaccinium darrowi Camp, which evolved in the absence of I. pepperi in the Southeastern U.S. V. corymbosum cv. "Elliott", was used as a susceptible control. Between population variability in I. pepperi resistance was assessed by measuring length of the prereproductive period, fecundity, and survivorship on 14 V. darrowi accessions representing 11 discrete wild populations. Length of I. pepperi's prereproductive period and survivorship were not significantly affected. However, differences were detected in fecundity and the intrinsic rate of increase (r ( m )). Within population variability in resistance was measured by confining first instars to 24 accessions from a single wild population of V. darrowi (NJ88-06). Significant differences in the mean total number of aphids occurring after 20 d were only detected between 2 of the 24 V. darrowi accessions. A greater degree of diversity in I. pepperi resistance exists between populations of V. darrowi compared to within a population. Constitutive leaf and stem polyphenolics were identified by HPLC-MS and quantified from 14 of the V. darrowi accessions. The accessions varied in concentrations of five phenolic acids and seven flavonol glycosides, but a correlation was not found between individual or total phenolics and aphid performance. Overall, screening within and between populations of V. darrowi identified promising sources of aphid resistance, but phenolic acid and flavonol glycoside profiles did not predict resistance levels. The mechanism of resistance remains to be identified.

  19. An Escherichia coli strain, PGB01, isolated from feral pigeon Faeces, thermally fit to survive in pigeon, shows high level resistance to trimethoprim.

    PubMed

    Kumar, Arvind; Tiwary, Bipransh Kumar; Kachhap, Sangita; Nanda, Ashis Kumar; Chakraborty, Ranadhir

    2015-01-01

    In this study, of the hundred Escherichia coli strains isolated from feral Pigeon faeces, eighty five strains were resistant to one or more antibiotics and fifteen sensitive to all the antibiotics tested. The only strain (among all antibiotic-resistant E. coli isolates) that possessed class 1 integron was PGB01. The dihydrofolate reductase gene of the said integron was cloned, sequenced and expressed in E. coli JM109. Since PGB01 was native to pigeon's gut, we have compared the growth of PGB01 at two different temperatures, 42°C (normal body temperature of pigeon) and 37°C (optimal growth temperature of E. coli; also the human body temperature), with E. coli K12. It was found that PGB01 grew better than the laboratory strain E. coli K12 at 37°C as well as at 42°C. In the thermal fitness assay, it was observed that the cells of PGB01 were better adapted to 42°C, resembling the average body temperature of pigeon. The strain PGB01 also sustained more microwave mediated thermal stress than E. coli K12 cells. The NMR spectra of the whole cells of PGB01 varied from E. coli K12 in several spectral peaks relating some metabolic adaptation to thermotolerance. On elevating the growth temperature from 37°C to 42°C, susceptibility to kanamycin (both strains were sensitive to it) of E. coli K12 was increased, but in case of PGB01 no change in susceptibility took place. We have also attempted to reveal the basis of trimethoprim resistance phenotype conferred by the dfrA7 gene homologue of PGB01. Molecular Dynamics (MD) simulation study of docked complexes, PGB01-DfrA7 and E. coli TMP-sensitive-Dfr with trimethoprim (TMP) showed loss of some of the hydrogen and hydrophobic interaction between TMP and mutated residues in PGB01-DfrA7-TMP complex compared to TMP-sensitive-Dfr-TMP complex. This loss of interaction entails decrease in affinity of TMP for PGB01-DfrA7 compared to TMP-sensitive-Dfr.

  20. Spice oil cinnamaldehyde exhibits potent anticandidal activity against fluconazole resistant clinical isolates.

    PubMed

    Shreaz, Sheikh; Bhatia, Rimple; Khan, Neelofar; Muralidhar, Sumathi; Basir, Seemi F; Manzoor, Nikhat; Khan, Luqman Ahmad

    2011-10-01

    Fluconazole resistance is becoming an important clinical concern. We studied the in vitro effects of cinnamaldehyde against 18 fluconazole-resistant Candida isolates. MIC(90) of cinnamaldehyde against different Candida isolates ranged 100-500 μg/ml. Growth and sensitivity of the organisms were significantly affected by cinnamaldehyde at different concentrations. The rapid irreversible action of this compound on fungal cells suggested membrane-located targets for its action. Insight studies to mechanism suggested that cinnamaldehyde exerts its antifungal activity by targeting sterol biosynthesis and plasma membrane ATPase activity. Inhibition of H(+) (-)ATPase leads to intracellular acidification and cell death. Toxicity against H9c2 rat cardiac myoblasts was studied to exclude the possibility of further associated cytotoxicity. The observed selectively fungicidal characteristics against fluconazole-resistant Candida isolates signify a promising candidature of this essential oil as an antifungal agent in treatments for candidosis.

  1. Kinetics of high-Level of ß-glucosidase production by a 2-deoxyglucose-resistant mutant of Humicola lanuginosa in submerged fermentation

    PubMed Central

    Bokhari, Syed Ali Imran; Latif, Farooq; Rajoka, Muhammad Ibrahim

    2008-01-01

    A 2-deoxyglucose-resistant mutant (M7) of Humicola lanuginosa was obtained by exposing conidia to γ-rays and permitting expression in broth containing 0.6% 2-deoxyglucose (DG) and cellobiose (1%) before plating on DG esculin-ferric ammonium citrate agar medium from which colonies showing faster and bigger blackening zones were selected. Kinetic parameters for enhanced ß-glucosidase (BGL) synthesis by M7 were achieved when corncobs acted as the carbon source. The combination between corncobs and corn steep liquor was the best to support higher values of all product formation kinetic parameters. Effect of temperature on the kinetic and thermodynamic attributes of BGL production equilibrium in the wild organism and M7 was studied using batch process at eight different temperatures in shake-flask studies. The best performance was found at 45°C and 20 g L−1 corncobs in 64 h. Both growth and product formation (17.93 U mL−1) were remarkably high at 45°C and both were coupled under optimum working conditions. Product yield of BGL from the mutant M7 (1556.5 U g−1 dry corncobs) was significantly higher than the values reported on all fungal and bacterial systems. Mutation had thermo-stabilization influence on the organism and mutant required lower activation energy for growth and lower magnitudes of enthalpy and entropy for product formation than those demanded by the wild organism, other mesophilic and thermo-tolerant organisms. In the inactivation phase, the organisms needed lower values of activation energy, enthalpy and entropy for product formation equilibrium, confirming thermophilic nature of metabolic network possessed by the mutant organism. PMID:24031297

  2. Excreting and non-excreting grasses exhibit different salt resistance strategies

    PubMed Central

    Moinuddin, Muhammad; Gulzar, Salman; Ahmed, Muhammad Zaheer; Gul, Bilquees; Koyro, Hans-Werner; Khan, Muhammad Ajmal

    2014-01-01

    The combination of traits that makes a plant successful under saline conditions varies with the type of plant and its interaction with the environmental conditions. Knowledge about the contribution of these traits towards salt resistance in grasses has great potential for improving the salt resistance of conventional crops. We attempted to identify differential adaptive response patterns of salt-excreting versus non-excreting grasses. More specifically, we studied the growth, osmotic, ionic and nutrient (carbon/nitrogen) relations of two salt-excreting (Aeluropus lagopoides and Sporobolus tremulus) and two non-excreting (Paspalum paspalodes and Paspalidium geminatum) perennial C4 grasses under non-saline and saline (0, 200 and 400 mM NaCl) conditions. Growth and relative growth rate decreased under saline conditions in the order P. geminatum > S. tremulus = A. lagopoides > P. paspalodes. The root-to-shoot biomass allocation was unaffected in salt-excreting grasses, increased in P. paspalodes but decreased in P. geminatum. Salt-excreting grasses had a higher shoot/root Na+ ratio than non-excreting grasses. K+, Ca2+ and Mg2+ homoeostasis remained undisturbed among test grasses possibly through improved ion selectivity with rising substrate salinity. Salt-excreting grasses increased leaf succulence, decreased ψs and xylem pressure potential, and accumulated proline and glycinebetaine with increasing salinity. Higher salt resistance of P. paspalodes could be attributed to lower Na+ uptake, higher nitrogen-use efficiency and higher water-use efficiency among the test species. However, P. geminatum was unable to cope with salt-induced physiological drought. More information is required to adequately document the differential strategies of salt resistance in salt-excreting and non-excreting grasses. PMID:24996428

  3. Physical Cross-Linking Starch-Based Zwitterionic Hydrogel Exhibiting Excellent Biocompatibility, Protein Resistance, and Biodegradability.

    PubMed

    Ye, Lei; Zhang, Yabin; Wang, Qiangsong; Zhou, Xin; Yang, Boguang; Ji, Feng; Dong, Dianyu; Gao, Lina; Cui, Yuanlu; Yao, Fanglian

    2016-06-22

    In this work, a novel starch-based zwitterionic copolymer, starch-graft-poly(sulfobetaine methacrylate) (ST-g-PSBMA), was synthesized via Atom Transfer Radical Polymerization. Starch, which formed the main chain, can be degraded completely in vivo, and the pendent segments of PSBMA endowed the copolymer with excellent protein resistance properties. This ST-g-PSBMA copolymer could self-assemble into a physical hydrogel in normal saline, and studies of the formation mechanism indicated that the generation of the physical hydrogel was driven by electrostatic interactions between PSBMA segments. The obtained hydrogels were subjected to detailed analysis by scanning electron microscopy, swelling ratio, protein resistance, and rheology tests. Toxicity and hemolysis analysis demonstrated that the ST-g-PSBMA hydrogels possess excellent biocompatibility and hemocompatibility. Moreover, the cytokine secretion assays (IL-6, TNF-α, and NO) confirmed that ST-g-PSBMA hydrogels had low potential to trigger the activation of macrophages and were suitable for in vivo biomedical applications. On the basis of these in vitro results, the ST-g-PSBMA hydrogels were implanted in SD rats. The tissue responses to hydrogel implantation and the hydrogel degradation in vivo were determined by histological analysis (Hematoxylin and eosin, Van Gieson, and Masson's Trichrome stains). The results presented in this study demonstrate that the physical cross-linking, starch-based zwitterionic hydrogels possess excellent protein resistance, low macrophage-activation properties, and good biocompatibility, and they are a promising candidate for an in vivo biomedical application platform.

  4. Microvascular endothelial cells exhibit optimal aspect ratio for minimizing flow resistance.

    PubMed

    Sumagin, Ronen; Brown, Carl W; Sarelius, Ingrid H; King, Michael R

    2008-04-01

    A recent analytical solution of the three-dimensional Stokes flow through a bumpy tube predicts that for a given bump area, there exists an optimal circumferential wavenumber which minimizes flow resistance. This study uses measurements of microvessel endothelial cell morphology to test whether this prediction holds in the microvasculature. Endothelial cell (EC) morphology was measured in blood perfused in situ microvessels in anesthetized mice using confocal intravital microscopy. EC borders were identified by immunofluorescently labeling the EC surface molecule ICAM-1 which is expressed on the surface but not in the EC border regions. Comparison of this theory with extensive in situ measurements of microvascular EC geometry in mouse cremaster muscle using intravital microscopy reveals that the spacing of EC nuclei in venules ranging from 27 to 106 microm in diameter indeed lies quite close to this predicted optimal configuration. Interestingly, arteriolar ECs are configured to minimize flow resistance not in the resting state, but at the dilated vessel diameter. These results raise the question of whether less organized circulatory systems, such as that found in newly formed solid tumors or in the developing embryo, may deviate from the optimal bump spacing predicted to minimize flow resistance.

  5. [In vitro susceptibility of Enterococcus strains to high level aminoglycosides and heavy metals].

    PubMed

    Nakipoğlu, Yaşar; Gümüş, Defne; Sertel Selale, Deniz; Küçüker, Mine Ang

    2009-10-01

    The widespread use of antimicrobial agents in the hospitals and environmental contamination with heavy metals are increasingly related to resistance progression in microorganisms. The aim of this study was to investigate the resistance of enterococci to high level aminoglycosides and some heavy metals [lead (Pb+2), cadmium (Cd+2), mercury (Hg+2), arsenic (As+5)]. A total of 39 Enterococcus strains, isolated from stool and rectal swabs of hospitalized patients were included to the study. Twenty of the strains were resistant to glycopeptides (11 were resistant to vancomycin + teicoplanin and 9 were resistant to only vancomycin). Disk diffusion method was performed to determine the high level resistance to aminoglycosides (gentamicin 120 microg and streptomycin 300 microg), and agar dilution method was used to detect the sensitivities of the strains against different concentrations (0.005-20 mM) of heavy metals. Since there is no specified minimum inhibitory concentration (MIC) breakpoints for heavy metals, resistance criteria described in previous studies were used. Accordingly, enterococci which exhibited MIC > or = 1 mM for lead and cadmium, MIC > or = 0.1 mM for mercury, and MIC > or = 10 mM for arsenic were accepted as resistant. High level aminoglycoside (HLAG) resistance rates were found as 91% (10/11) for vancomycin (V) + teicoplanin (T) resistant and 42% (8/19) for glycopeptide susceptible strains. While all of the isolates were resistant to lead (100%), arsenic (2.6%) and mercury (2.6%) resistance was detected in one isolate for each metal. No cadmium resistance has been detected. In our study, enterococci have exhibited seven different resistance profiles (10 strains were resistant to V + T + HLAG + Pb; 1 was resistant to V + T + Pb; 1 was resistant to V + As + Pb; 1 was resistant to HLAG + Hg + Pb; 8 were resistant to V + Pb; 7 were resistant to HLAG + Pb; 11 were only resistant to Pb). Resistance to antibiotics (aminoglycosides and/or vancomycin and

  6. Acrylic coatings exhibiting improved hardness, solvent resistance and glossiness by using silica nano-composites

    NASA Astrophysics Data System (ADS)

    Dashtizadeh, Ahmad; Abdouss, Majid; Mahdavi, Hossein; Khorassani, Manuchehr

    2011-01-01

    To prepare nano-composite emulsion acrylic resins with improved surface hardness and solvent resistance, nano-silica particles were treated with surfactants. The monomers of methyl methacrylate/butylacrylate were co-polymerized on the surface of dispersed silica particles. Several emulsions with different silica contents and copolymer mole fractions were prepared. Finally the emulsions were modified to water-based acrylic coatings and improved properties such as surface hardness, solvent resistance and glossiness were determined. The study of coatings was directed to find the improved resin by optimum surface properties. Size distribution and morphology of latexes were characterized by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy and scanning electron microscopy. The glass transition temperature of nano-composites was measured and discussed its relation with silica contents, monomer mole fractions and improved properties of coatings. The optimum pendulum hardness of coatings was on 0.46 methyl methacrylate mole fraction and 120 g silica content. An increase in pendulum hardness of nano-composites with the addition of modified silica was observed. DLS and TEM studies indicate that silica particles were dispersed homogenously through the polymer matrix.

  7. Bacillus thermoamylovorans Spores with Very-High-Level Heat Resistance Germinate Poorly in Rich Medium despite the Presence of ger Clusters but Efficiently upon Exposure to Calcium-Dipicolinic Acid

    PubMed Central

    Berendsen, Erwin M.; Krawczyk, Antonina O.; Klaus, Verena; de Jong, Anne; Boekhorst, Jos; Eijlander, Robyn T.

    2015-01-01

    High-level heat resistance of spores of Bacillus thermoamylovorans poses challenges to the food industry, as industrial sterilization processes may not inactivate such spores, resulting in food spoilage upon germination and outgrowth. In this study, the germination and heat resistance properties of spores of four food-spoiling isolates were determined. Flow cytometry counts of spores were much higher than their counts on rich medium (maximum, 5%). Microscopic analysis revealed inefficient nutrient-induced germination of spores of all four isolates despite the presence of most known germination-related genes, including two operons encoding nutrient germinant receptors (GRs), in their genomes. In contrast, exposure to nonnutrient germinant calcium-dipicolinic acid (Ca-DPA) resulted in efficient (50 to 98%) spore germination. All four strains harbored cwlJ and gerQ genes, which are known to be essential for Ca-DPA-induced germination in Bacillus subtilis. When determining spore survival upon heating, low viable counts can be due to spore inactivation and an inability to germinate. To dissect these two phenomena, the recoveries of spores upon heat treatment were determined on plates with and without preexposure to Ca-DPA. The high-level heat resistance of spores as observed in this study (D120°C, 1.9 ± 0.2 and 1.3 ± 0.1 min; z value, 12.2 ± 1.8°C) is in line with survival of sterilization processes in the food industry. The recovery of B. thermoamylovorans spores can be improved via nonnutrient germination, thereby avoiding gross underestimation of their levels in food ingredients. PMID:26341201

  8. Epac2a-null mice exhibit obesity-prone nature more susceptible to leptin resistance

    PubMed Central

    Hwang, M; Go, Y; Park, J-H; Shin, S-K; Song, S E; Oh, B-C; Im, S-S; Hwang, I; Jeon, Y H; Lee, I-K; Seino, S; Song, D-K

    2017-01-01

    Background: The exchange protein directly activated by cAMP (Epac), which is primarily involved in cAMP signaling, has been known to be essential for controlling body energy metabolism. Epac has two isoforms: Epac1 and Epac2. The function of Epac1 on obesity was unveiled using Epac1 knockout (KO) mice. However, the role of Epac2 in obesity remains unclear. Methods: To evaluate the role of Epac2 in obesity, we used Epac2a KO mice, which is dominantly expressed in neurons and endocrine tissues. Physiological factors related to obesity were analyzed: body weight, fat mass, food intake, plasma leptin and adiponectin levels, energy expenditure, glucose tolerance, and insulin and leptin resistance. To determine the mechanism of Epac2a, mice received exogenous leptin and then hypothalamic leptin signaling was analyzed. Results: Epac2a KO mice appeared to have normal glucose tolerance and insulin sensitivity until 12 weeks of age, but an early onset increase of plasma leptin levels and decrease of plasma adiponectin levels compared with wild-type mice. Acute leptin injection revealed impaired hypothalamic leptin signaling in KO mice. Consistently, KO mice fed a high-fat diet (HFD) were significantly obese, presenting greater food intake and lower energy expenditure. HFD-fed KO mice were also characterized by greater impairment of hypothalamic leptin signaling and by weaker leptin-induced decrease in food consumption compared with HFD-fed wild-type mice. In wild-type mice, acute exogenous leptin injection or chronic HFD feeding tended to induce hypothalamic Epac2a expression. Conclusions: Considering that HFD is an inducer of hypothalamic leptin resistance and that Epac2a functions in pancreatic beta cells during demands of greater work load, hypothalamic Epac2a may have a role in facilitating leptin signaling, at least in response to higher metabolic demands. Thus, our data indicate that Epac2a is critical for preventing obesity and thus Epac2a activators may be used to

  9. D-β-aspartyl residue exhibiting uncommon high resistance to spontaneous peptide bond cleavage

    NASA Astrophysics Data System (ADS)

    Aki, Kenzo; Okamura, Emiko

    2016-02-01

    Although L-amino acids were selected as main constituents of peptides and proteins during chemical evolution, D-aspartyl (Asp) residue is found in a variety of living tissues. In particular, D-β-Asp is thought to be stable than any other Asp isomers, and this could be a reason for gradual accumulation in abnormal proteins and peptides to modify their structures and functions. It is predicted that D-β-Asp shows high resistance to biomolecular reactions. For instance, less reactivity of D-β-Asp is expected to bond cleavage, although such information has not been provided yet. In this work, the spontaneous peptide bond cleavage was compared between Asp isomers, by applying real-time solution-state NMR to eye lens αΑ-crystallin 51–60 fragment, S51LFRTVLD58SG60 and αΒ-crystallin 61–67 analog, F61D62TGLSG67 consisting of L-α- and D-β-Asp 58 and 62, respectively. Kinetic analysis showed how tough the uncommon D-β-Asp residue was against the peptide bond cleavage as compared to natural L-α-Asp. Differences in pKa and conformation between L-α- and D-β-Asp side chains were plausible factors to determine reactivity of Asp isomers. The present study, for the first time, provides a rationale to explain less reactivity of D-β-Asp to allow abnormal accumulation.

  10. Alx3-deficient mice exhibit folic acid-resistant craniofacial midline and neural tube closure defects.

    PubMed

    Lakhwani, Sita; García-Sanz, Patricia; Vallejo, Mario

    2010-08-15

    Neural tube closure defects are among the most frequent congenital malformations in humans. Supplemental maternal intake of folic acid before and during pregnancy reduces their incidence significantly, but the mechanism underlying this preventive effect is unknown. As a number of genes that cause neural tube closure defects encode transcriptional regulators in mice, one possibility is that folic acid could induce the expression of transcription factors to compensate for the primary genetic defect. We report that folic acid is required in mouse embryos for the specific expression of the homeodomain gene Alx3 in the head mesenchyme, an important tissue for cranial neural tube closure. Alx3-deficient mice exhibit increased failure of cranial neural tube closure and increased cell death in the craniofacial region, two effects that are also observed in wild type embryos developing in the absence of folic acid. Folic acid cannot prevent these defects in Alx3-deficient embryos, indicating that one mechanism of folic acid action is through induced expression of Alx3. Thus, Alx3 emerges as a candidate gene for human neural tube defects and reveals the existence of induced transcription factor gene expression as a previously unknown mechanism by which folic acid prevents neural tube closure defects.

  11. Trichosporon inkin biofilms produce extracellular proteases and exhibit resistance to antifungals.

    PubMed

    de Aguiar Cordeiro, Rossana; Serpa, Rosana; Flávia Uchoa Alexandre, Camila; de Farias Marques, Francisca Jakelyne; Vladia Silva de Melo, Charlline; da Silva Franco, Jônatas; José de Jesus Evangelista, Antonio; Pires de Camargo, Zoilo; Samia Nogueira Brilhante, Raimunda; Fabio Gadelha Rocha, Marcos; Luciano Bezerra Moreira, José; de Jesus Pinheiro Gomes Bandeira, Tereza; Júlio Costa Sidrim, José

    2015-11-01

    The aim of this study was to determine experimental conditions for in vitro biofilm formation of clinical isolates of Trichosporon inkin, an important opportunistic pathogen in immunocompromised patients. Biofilms were formed in microtitre plates in three different media (RPMI, Sabouraud and CLED), with inocula of 104, 105 or 106 cells ml- 1, at pH 5.5 and 7.0, and at 35 and 28 °C, under static and shaking conditions for 72 h. Growth kinetics of biofilms were evaluated at 6, 24, 48 and 72 h. Biofilm milieu analysis were assessed by counting viable cells and quantification of nucleic acids released into biofilm supernatants. Biofilms were also analysed for proteolytic activity and antifungal resistance against amphotericin B, caspofungin, fluconazole, itraconazole and voriconazole. Finally, ultrastructural characterization of biofilms formed in microtitre plates and catheter disks was performed by scanning electron microscopy. Greater biofilm formation was observed with a starter inoculum of 106 cells ml- 1, at pH 7.0 at 35 °C and 80 r.p.m., in both RPMI and Sabouraud media. Growth kinetics showed an increase in both viable cells and biomass with increasing incubation time, with maximum production at 48 h. Biofilms were able to disperse viable cells and nucleic acids into the supernatant throughout the developmental cycle. T. inkin biofilms produced more protease than planktonic cells and showed high tolerance to amphotericin B, caspofungin and azole derivatives. Mature biofilms were formed by different morphotypes, such as blastoconidia, arthroconidia and hyphae, in a strain-specific manner. The present article details the multicellular lifestyle of T. inkin and provides perspectives for further research.

  12. Blastocystis Isolate B Exhibits Multiple Modes of Resistance against Antimicrobial Peptide LL-37

    PubMed Central

    Yason, John Anthony; Ajjampur, Sitara Swarna Rao

    2016-01-01

    Blastocystis is one of the most common eukaryotic organisms found in humans and many types of animals. Several reports have identified its role in gastrointestinal disorders, although its pathogenicity is yet to be clarified. Blastocystis is transmitted via the fecal-to-oral route and colonizes the large intestines. Epithelial cells lining the intestine secrete antimicrobial peptides (AMPs), including beta-defensins and cathelicidin, as a response to infection. This study explores the effects of host colonic antimicrobial peptides, particularly LL-37, a fragment of cathelicidin, on different Blastocystis subtypes. Blastocystis is composed of several subtypes that have genetic, metabolic, and biological differences. These subtypes also have various outcomes in terms of drug treatment and immune response. In this study, Blastocystis isolates from three different subtypes were found to induce intestinal epithelial cells to secrete LL-37. We also show that among the antimicrobial peptides tested, only LL-37 has broad activity on all the subtypes. LL-37 causes membrane disruption and causes Blastocystis to change shape. Blastocystis subtype 7 (ST7), however, showed relative resistance to LL-37. An isolate, ST7 isolate B (ST7-B), from this subtype releases proteases that can degrade the peptide. It also makes the environment acidic, which causes attenuation of LL-37 activity. The Blastocystis ST7-B isolate was also observed to have a thicker surface coat, which may protect the parasite from direct killing by LL-37. This study determined the effects of LL-37 on different Blastocystis isolates and indicates that AMPs have significant roles in Blastocystis infections. PMID:27217421

  13. Fabrication and Characterization of a Micromachined Swirl-Shaped Ionic Polymer Metal Composite Actuator with Electrodes Exhibiting Asymmetric Resistance

    PubMed Central

    Feng, Guo-Hua; Liu, Kim-Min

    2014-01-01

    This paper presents a swirl-shaped microfeatured ionic polymer-metal composite (IPMC) actuator. A novel micromachining process was developed to fabricate an array of IPMC actuators on a glass substrate and to ensure that no shortcircuits occur between the electrodes of the actuator. We demonstrated a microfluidic scheme in which surface tension was used to construct swirl-shaped planar IPMC devices of microfeature size and investigated the flow velocity of Nafion solutions, which formed the backbone polymer of the actuator, within the microchannel. The unique fabrication process yielded top and bottom electrodes that exhibited asymmetric surface resistance. A tool for measuring surface resistance was developed and used to characterize the resistances of the electrodes for the fabricated IPMC device. The actuator, which featured asymmetric electrode resistance, caused a nonzero-bias current when the device was driven using a zero-bias square wave, and we propose a circuit model to describe this phenomenon. Moreover, we discovered and characterized a bending and rotating motion when the IPMC actuator was driven using a square wave. We observed a strain rate of 14.6% and a displacement of 700 μm in the direction perpendicular to the electrode surfaces during 4.5-V actuation. PMID:24824370

  14. Fabrication and characterization of a micromachined swirl-shaped ionic polymer metal composite actuator with electrodes exhibiting asymmetric resistance.

    PubMed

    Feng, Guo-Hua; Liu, Kim-Min

    2014-05-12

    This paper presents a swirl-shaped microfeatured ionic polymer-metal composite (IPMC) actuator. A novel micromachining process was developed to fabricate an array of IPMC actuators on a glass substrate and to ensure that no shortcircuits occur between the electrodes of the actuator. We demonstrated a microfluidic scheme in which surface tension was used to construct swirl-shaped planar IPMC devices of microfeature size and investigated the flow velocity of Nafion solutions, which formed the backbone polymer of the actuator, within the microchannel. The unique fabrication process yielded top and bottom electrodes that exhibited asymmetric surface resistance. A tool for measuring surface resistance was developed and used to characterize the resistances of the electrodes for the fabricated IPMC device. The actuator, which featured asymmetric electrode resistance, caused a nonzero-bias current when the device was driven using a zero-bias square wave, and we propose a circuit model to describe this phenomenon. Moreover, we discovered and characterized a bending and rotating motion when the IPMC actuator was driven using a square wave. We observed a strain rate of 14.6% and a displacement of 700 μm in the direction perpendicular to the electrode surfaces during 4.5-V actuation.

  15. Identification and characterization of a Streptomyces sp. isolate exhibiting activity against multidrug-resistant coagulase-negative Staphylococci.

    PubMed

    Sadigh-Eteghad, Saeed; Dehnad, Alireza; Shanebandi, Dariush; Khalili, Iraj; Razmarayii, Nasser; Namvaran, Ali

    2011-12-01

    The resistance of 220 coagulase-negative Staphylococci (CNS) (associated with animal disease) to 13 antibiotics were determined using the disk diffusion method. 35.9% of multidrug-resistant coagulase-negative Staphylococci (MR-CNS) exhibited resistance to five or more than five antibiotics; all of these bacteria were resistant to methicillin too. The new Streptomyces sp. ABRIINW111 was isolated from the Zagros Mountains Hamadan, Iran. The 16S rDNA sequence of the isolate indicated that it has 98% similarity to S. levis, but some mutations in the alpha and gamma regions of the 16S rDNA sequence emphasize the probability of the existence of a new species. Preliminary and secondary antibacterial screenings revealed that the isolate is active against gram negative and positive bacteria. The diethyl ether extracted metabolite of the Streptomyces sp. ABRIINW111 showed an effective antibacterial activity against MR-CNS. So the diethyl ether extract of the new Streptomyces sp. strain ABRIINW111 can inhibit the MR-CNS in vitro, and it can offer a new approach to treat MR-CNS infectious patients.

  16. Perovskite-type metal oxides exhibiting negligible grain boundary resistance to total electrical conductivity.

    PubMed

    Pannu, Tania; Pannu, Kanwar Gulsher Singh; Thangadurai, Venkataraman

    2011-01-17

    In this paper, we report the synthesis, structure and electrical properties of the perovskite-type AZn0.33+xNb0.67-xO3-δ (A = Sr or Ba; 0 ≤ x ≤ 0.08). The investigated compounds were prepared by employing the solid-state (ceramic) reaction using alkaline nitrates, zinc oxide, and niobium oxide at elevated temperatures in air. Powder X-ray diffraction (PXRD) showed the formation of disordered Zn and Nb at the B-sites of space group Pm3̅m with cubic structure and a lattice constant comparable to that of the literature. The AC impedance study showed mainly bulk contribution to the total electrical conductivity over the investigated frequency range of 0.01 Hz to 1 MHz in all the investigated atmospheres even at low temperatures, which is significantly different from that of the well-known perovskite-type B-site ordered BaCa0.33+xNb0.67-xO3-δ and the disordered acceptor-doped BaCeO3. The bulk dielectric constant determined at 500 and 700 °C in air was found to be in the range of 35-100. In air, the isothermal bulk dielectric constant seems to increase with an increasing Zn content, and a similar trend was observed for total electrical conductivity. In dry and wet H2, the electrical conductivity decreases with an increasing Zn content in AZn0.33+xNb0.67-xO3-δ, and the x = 0 member of the Ba compound exhibits the highest total conductivity of 7.2 × 10(-3) S cm(-1) in dry H2 at 800 °C. Both Sr and Ba compounds were found to be stable against the reaction with pure CO2 at 700 °C and H2O at 100 °C for a long period of time. SrZn0.33+xNb0.67-xO3-δ was found to be stable in 30 ppm H2S at 800 °C, while the corresponding Ba compound formed reaction products such as BaS (JCPDS Card 01-0757), BaS2 (JCPDS Card 21-0087), and BaS3 (JCPDS Card 03-0824).

  17. The presence of the region on pBR322 that encodes resistance to tetracycline is responsible for high levels of plasmid DNA knotting in Escherichia coli DNA topoisomerase I deletion mutant.

    PubMed Central

    Shishido, K; Ishii, S; Komiyama, N

    1989-01-01

    Plasmid pBR322 DNA isolated from Escherichia coli DNA topoisomerase I deletion mutant DM800 is estimated to contain about 10% of the knotted forms (Shishido et al., 1987). These knotted DNA species were shown to have the same primary structure as usual, unknotted pBR322 DNA. Analysis of the knotting level of deletion, insertion and sequence-rearranged derivatives of pBR322 in DM800 showed that the presence of the region on pBR322 encoding resistance to tetracycline (tet) is required for high levels of plasmid knotting. When the entire tet region is present in a native orientation, the level of knotting is highest. Inactivating the tet promoter is manifested by a middle level of knotting. For deletion derivatives lacking various portions of the tet region, the level of knotting ranges from lowest to high depending on the site and length of the tet gene remaining. Inverting the orientation of tet region on the pBR322 genome results in a middle level of knotting. Deleting the ampicillin-resistance (bla)gene outside of its second promoter does not affect the level of knotting, if the entire tet gene remains. A possible mechanism of regulation of plasmid knotting is discussed. Images PMID:2557587

  18. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

    Presents a method to calculate the amount of high-level radioactive waste by taking into consideration the following factors: the fission process that yields the waste, identification of the waste, the energy required to run a 1-GWe plant for one year, and the uranium mass required to produce that energy. Briefly discusses waste disposal and…

  19. Process for solidifying high-level nuclear waste

    DOEpatents

    Ross, Wayne A.

    1978-01-01

    The addition of a small amount of reducing agent to a mixture of a high-level radioactive waste calcine and glass frit before the mixture is melted will produce a more homogeneous glass which is leach-resistant and suitable for long-term storage of high-level radioactive waste products.

  20. RPython high-level synthesis

    NASA Astrophysics Data System (ADS)

    Cieszewski, Radoslaw; Linczuk, Maciej

    2016-09-01

    The development of FPGA technology and the increasing complexity of applications in recent decades have forced compilers to move to higher abstraction levels. Compilers interprets an algorithmic description of a desired behavior written in High-Level Languages (HLLs) and translate it to Hardware Description Languages (HDLs). This paper presents a RPython based High-Level synthesis (HLS) compiler. The compiler get the configuration parameters and map RPython program to VHDL. Then, VHDL code can be used to program FPGA chips. In comparison of other technologies usage, FPGAs have the potential to achieve far greater performance than software as a result of omitting the fetch-decode-execute operations of General Purpose Processors (GPUs), and introduce more parallel computation. This can be exploited by utilizing many resources at the same time. Creating parallel algorithms computed with FPGAs in pure HDL is difficult and time consuming. Implementation time can be greatly reduced with High-Level Synthesis compiler. This article describes design methodologies and tools, implementation and first results of created VHDL backend for RPython compiler.

  1. The CMS High Level Trigger

    NASA Astrophysics Data System (ADS)

    Trocino, Daniele

    2014-06-01

    The CMS experiment has been designed with a two-level trigger system: the Level-1 Trigger, implemented in custom-designed electronics, and the High-Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. A software trigger system requires a tradeoff between the complexity of the algorithms running with the available computing power, the sustainable output rate, and the selection efficiency. We present the performance of the main triggers used during the 2012 data taking, ranging from simple single-object selections to more complex algorithms combining different objects, and applying analysis-level reconstruction and selection. We discuss the optimisation of the trigger and the specific techniques to cope with the increasing LHC pile-up, reducing its impact on the physics performance.

  2. Optimizing High Level Waste Disposal

    SciTech Connect

    Dirk Gombert

    2005-09-01

    If society is ever to reap the potential benefits of nuclear energy, technologists must close the fuel-cycle completely. A closed cycle equates to a continued supply of fuel and safe reactors, but also reliable and comprehensive closure of waste issues. High level waste (HLW) disposal in borosilicate glass (BSG) is based on 1970s era evaluations. This host matrix is very adaptable to sequestering a wide variety of radionuclides found in raffinates from spent fuel reprocessing. However, it is now known that the current system is far from optimal for disposal of the diverse HLW streams, and proven alternatives are available to reduce costs by billions of dollars. The basis for HLW disposal should be reassessed to consider extensive waste form and process technology research and development efforts, which have been conducted by the United States Department of Energy (USDOE), international agencies and the private sector. Matching the waste form to the waste chemistry and using currently available technology could increase the waste content in waste forms to 50% or more and double processing rates. Optimization of the HLW disposal system would accelerate HLW disposition and increase repository capacity. This does not necessarily require developing new waste forms, the emphasis should be on qualifying existing matrices to demonstrate protection equal to or better than the baseline glass performance. Also, this proposed effort does not necessarily require developing new technology concepts. The emphasis is on demonstrating existing technology that is clearly better (reliability, productivity, cost) than current technology, and justifying its use in future facilities or retrofitted facilities. Higher waste processing and disposal efficiency can be realized by performing the engineering analyses and trade-studies necessary to select the most efficient methods for processing the full spectrum of wastes across the nuclear complex. This paper will describe technologies being

  3. A Redesigned Vancomycin Engineered for Dual D-Ala-D-Ala and D-Ala-D-Lac Binding Exhibits Potent Antimicrobial Activity Against Vancomycin-Resistant Bacteria

    PubMed Central

    Xie, Jian; Pierce, Joshua G.; James, Robert C.; Okano, Akinori; Boger, Dale L.

    2011-01-01

    The emergence of bacteria resistant to vancomycin, often the antibiotic of last resort, poses a major health problem. Vancomycin-resistant bacteria sense a glycopeptide antibiotic challenge and remodel their cell wall precursor peptidoglycan terminus from D-Ala-d-Ala to D-Ala-D-Lac, reducing the binding of vancomycin to its target 1000-fold and accounting for the loss in antimicrobial activity. Here, we report [Φ[C(=NH)NH]Tpg4]-vancomycin aglycon designed to exhibit the dual binding to D-Ala-D-Ala and D-Ala-D-Lac needed to reinstate activity against vancomycin-resistant bacteria. Its binding to a model D-Ala-D-Ala ligand was found to be only two-fold less than vancomycin aglycon and this affinity was maintained with a model D-Ala-D-Lac ligand, representing a 600-fold increase relative to vancomycin aglycon. Accurately reflecting these binding characteristics, it exhibits potent antimicrobial activity against vancomycin-resistant bacteria (MIC = 0.31 g/mL, VanA VRE). Thus, a complementary single atom exchange in the vancomycin core structure (O NH) to counter the single atom exchange in the cell wall precursors of resistant bacteria (NH O) reinstates potent antimicrobial activity and charts a rational path forward for the development of antibiotics for the treatment of vancomycin-resistant bacterial infections. PMID:21823662

  4. Candidate Genes That May Be Responsible for the Unusual Resistances Exhibited by Bacillus pumilus SAFR-032 Spores

    PubMed Central

    Tirumalai, Madhan R.; Rastogi, Rajat; Zamani, Nader; O’Bryant Williams, Elisha; Allen, Shamail; Diouf, Fatma; Kwende, Sharon; Weinstock, George M.; Venkateswaran, Kasthuri J.; Fox, George E.

    2013-01-01

    The spores of several Bacillus species, including Bacillus pumilus SAFR-032 and B. safensis FO-36b, which were isolated from the spacecraft assembly facility at NASA's Jet Propulsion Laboratory, are unusually resistant to UV radiation and hydrogen peroxide. In order to identify candidate genes that might be associated with these resistances, the whole genome of B. pumilus SAFR-032, and the draft genome of B. safensis FO-36b were compared in detail with the very closely related type strain B. pumilus ATCC7061T. 170 genes are considered characteristic of SAFR-032, because they are absent from both FO-36b and ATCC7061T. Forty of these SAFR-032 characteristic genes are entirely unique open reading frames. In addition, four genes are unique to the genomes of the resistant SAFR-032 and FO-36b. Fifty three genes involved in spore coat formation, regulation and germination, DNA repair, and peroxide resistance, are missing from all three genomes. The vast majority of these are cleanly deleted from their usual genomic context without any obvious replacement. Several DNA repair and peroxide resistance genes earlier reported to be unique to SAFR-032 are in fact shared with ATCC7061T and no longer considered to be promising candidates for association with the elevated resistances. Instead, several SAFR-032 characteristic genes were identified, which along with one or more of the unique SAFR-032 genes may be responsible for the elevated resistances. These new candidates include five genes associated with DNA repair, namely, BPUM_0608 a helicase, BPUM_0652 an ATP binding protein, BPUM_0653 an endonuclease, BPUM_0656 a DNA cytosine-5- methyltransferase, and BPUM_3674 a DNA helicase. Three of these candidate genes are in immediate proximity of two conserved hypothetical proteins, BPUM_0654 and BPUM_0655 that are also absent from both FO-36b and ATCC7061T. This cluster of five genes is considered to be an especially promising target for future experimental work. PMID:23799069

  5. Candidate genes that may be responsible for the unusual resistances exhibited by Bacillus pumilus SAFR-032 spores.

    PubMed

    Tirumalai, Madhan R; Rastogi, Rajat; Zamani, Nader; O'Bryant Williams, Elisha; Allen, Shamail; Diouf, Fatma; Kwende, Sharon; Weinstock, George M; Venkateswaran, Kasthuri J; Fox, George E

    2013-01-01

    The spores of several Bacillus species, including Bacillus pumilus SAFR-032 and B. safensis FO-36b, which were isolated from the spacecraft assembly facility at NASA's Jet Propulsion Laboratory, are unusually resistant to UV radiation and hydrogen peroxide. In order to identify candidate genes that might be associated with these resistances, the whole genome of B. pumilus SAFR-032, and the draft genome of B. safensis FO-36b were compared in detail with the very closely related type strain B. pumilus ATCC7061(T). 170 genes are considered characteristic of SAFR-032, because they are absent from both FO-36b and ATCC7061(T). Forty of these SAFR-032 characteristic genes are entirely unique open reading frames. In addition, four genes are unique to the genomes of the resistant SAFR-032 and FO-36b. Fifty three genes involved in spore coat formation, regulation and germination, DNA repair, and peroxide resistance, are missing from all three genomes. The vast majority of these are cleanly deleted from their usual genomic context without any obvious replacement. Several DNA repair and peroxide resistance genes earlier reported to be unique to SAFR-032 are in fact shared with ATCC7061(T) and no longer considered to be promising candidates for association with the elevated resistances. Instead, several SAFR-032 characteristic genes were identified, which along with one or more of the unique SAFR-032 genes may be responsible for the elevated resistances. These new candidates include five genes associated with DNA repair, namely, BPUM_0608 a helicase, BPUM_0652 an ATP binding protein, BPUM_0653 an endonuclease, BPUM_0656 a DNA cytosine-5- methyltransferase, and BPUM_3674 a DNA helicase. Three of these candidate genes are in immediate proximity of two conserved hypothetical proteins, BPUM_0654 and BPUM_0655 that are also absent from both FO-36b and ATCC7061(T). This cluster of five genes is considered to be an especially promising target for future experimental work.

  6. KPC-Producing Klebsiella pneumoniae Strains That Harbor AAC(6′)-Ib Exhibit Intermediate Resistance to Amikacin

    PubMed Central

    Bremmer, Derek N.; Clancy, Cornelius J.; Press, Ellen G.; Almaghrabi, Reem; Chen, Liang; Doi, Yohei; Nguyen, M. Hong

    2014-01-01

    The aminoglycoside-modifying enzyme AAC(6′)-Ib is common among carbapenem-resistant Klebsiella pneumoniae (CR-Kp) strains. We investigated amikacin (AMK) activity against 20 AAC(6′)-Ib-producing CR-Kp strains. MICs clustered at 16 to 32 μg/ml. By the time-kill study, AMK (1× and 4× the MIC) was bactericidal against 30% and 85% of the strains, respectively. At achievable human serum concentrations, however, the majority of strains showed regrowth, suggesting that AAC(6′)-Ib confers intermediate AMK resistance. AMK and trimethoprim-sulfamethoxazole (TMP-SMX) were synergistic against 90% of the strains, indicating that the combination may overcome resistance. PMID:25288089

  7. Histones from Avian Erythrocytes Exhibit Antibiofilm activity against methicillin-sensitive and methicillin-resistant Staphylococcus aureus

    PubMed Central

    Rose-Martel, Megan; Kulshreshtha, Garima; Ahferom Berhane, Nahom; Jodoin, Joelle; Hincke, Maxwell T.

    2017-01-01

    Staphylococcus aureus, a human pathogen associated with many illnesses and post-surgical infections, can resist treatment due to the emergence of antibiotic-resistant strains and through biofilm formation. The current treatments for chronic biofilm infections are antibiotics and/or surgical removal of the contaminated medical device. Due to higher morbidity and mortality rates associated with overuse/misuse of antibiotics, alternate treatments are essential. This study reports the antibiofilm activity of avian erythrocyte histones against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). Fluorescence and scanning electron microscopy revealed membrane damage to bacteria in histone-treated biofilms. Histones and indolicidin (positive control) increased the expression of apsS and apsR, which are associated with the Antimicrobial Peptide (AMP) sensor/regulator system in S. aureus. The expression of dltB, and vraF, associated with AMP resistance mechanisms, were under histone inducible control in the biofilm-embedded bacterial cells. The time kill kinetics for histones against S. aureus revealed a rapid biocidal activity (<5 min). Purified erythrocyte-specific histone H5 possessed 3–4 fold enhanced antimicrobial activity against planktonic cells compared to the histone mixture (H1, H2A, H2B, H3, H4, H5). These results demonstrate the promise of histones and histone-like derivatives as novel antibiotics against pathogens in their planktonic and biofilm forms. PMID:28378802

  8. Transcriptomic analysis of multidrug-resistant Salmonella enterica serovar Typhimurium isolates that exhibit a tetracycline-induced invasion phenotype

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella is a highly prevalent bacterial food-borne disease in the U.S. and is estimated to cause over 1 million cases, 19,000 hospitalizations, and 350 deaths every year. Multidrug-resistant (MDR) Salmonella has emerged as an important food safety concern as it is associated with increased morbi...

  9. Phenylthiazole Antibacterial Agents Targeting Cell Wall Synthesis Exhibit Potent Activity in Vitro and in Vivo against Vancomycin-Resistant Enterococci.

    PubMed

    Mohammad, Haroon; Younis, Waleed; Chen, Lu; Peters, Christine E; Pogliano, Joe; Pogliano, Kit; Cooper, Bruce; Zhang, Jianan; Mayhoub, Abdelrahman; Oldfield, Eric; Cushman, Mark; Seleem, Mohamed N

    2017-03-23

    The emergence of antibiotic-resistant bacterial species, such as vancomycin-resistant enterococci (VRE), necessitates the development of new antimicrobials. Here, we investigate the spectrum of antibacterial activity of three phenylthiazole-substituted aminoguanidines. These compounds possess potent activity against VRE, inhibiting growth of clinical isolates at concentrations as low as 0.5 μg/mL. The compounds exerted a rapid bactericidal effect, targeting cell wall synthesis. Transposon mutagenesis suggested three possible targets: YubA, YubB (undecaprenyl diphosphate phosphatase (UPPP)), and YubD. Both UPPP as well as undecaprenyl diphosphate synthase were inhibited by compound 1. YubA and YubD are annotated as transporters and may also be targets because 1 collapsed the proton motive force in membrane vesicles. Using Caenorhabditis elegans, we demonstrate that two compounds (1, 3, at 20 μg/mL) retain potent activity in vivo, significantly reducing the burden of VRE in infected worms. Taken altogether, the results indicate that compounds 1 and 3 warrant further investigation as novel antibacterial agents against drug-resistant enterococci.

  10. Transgenic Sugarcane with a cry1Ac Gene Exhibited Better Phenotypic Traits and Enhanced Resistance against Sugarcane Borer

    PubMed Central

    Gao, Shiwu; Yang, Yingying; Wang, Chunfeng; Guo, Jinlong; Zhou, Dinggang; Wu, Qibin; Su, Yachun; Xu, Liping

    2016-01-01

    We developed sugarcane plants with improved resistance to the sugarcane borer, Diatraea saccharalis (F). An expression vector pGcry1Ac0229, harboring the cry1Ac gene and the selectable marker gene, bar, was constructed. This construct was introduced into the sugarcane cultivar FN15 by particle bombardment. Transformed plantlets were identified after selection with Phosphinothricin (PPT) and Basta. Plantlets were then screened by PCR based on the presence of cry1Ac and 14 cry1Ac positive plantlets were identified. Real-time quantitative PCR (RT-qPCR) revealed that the copy number of cry1Ac gene in the transgenic lines varied from 1 to 148. ELISA analysis showed that Cry1Ac protein levels in 7 transgenic lines ranged from 0.85 μg/FWg to 70.92 μg/FWg in leaves and 0.04 μg/FWg to 7.22 μg/FWg in stems, and negatively correlated to the rate of insect damage that ranged from 36.67% to 13.33%, respectively. Agronomic traits of six transgenic sugarcane lines with medium copy numbers were similar to the non-transgenic parental line. However, phenotype was poor in lines with high or low copy numbers. Compared to the non-transgenic control plants, all transgenic lines with medium copy numbers had relatively equal or lower sucrose yield and significantly improved sugarcane borer resistance, which lowered susceptibility to damage by insects. This suggests that the transgenic sugarcane lines harboring medium copy numbers of the cry1Ac gene may have significantly higher resistance to sugarcane borer but the sugarcane yield in these lines is similar to the non-transgenic control thus making them superior to the control lines. PMID:27093437

  11. Transgenic Sugarcane with a cry1Ac Gene Exhibited Better Phenotypic Traits and Enhanced Resistance against Sugarcane Borer.

    PubMed

    Gao, Shiwu; Yang, Yingying; Wang, Chunfeng; Guo, Jinlong; Zhou, Dinggang; Wu, Qibin; Su, Yachun; Xu, Liping; Que, Youxiong

    2016-01-01

    We developed sugarcane plants with improved resistance to the sugarcane borer, Diatraea saccharalis (F). An expression vector pGcry1Ac0229, harboring the cry1Ac gene and the selectable marker gene, bar, was constructed. This construct was introduced into the sugarcane cultivar FN15 by particle bombardment. Transformed plantlets were identified after selection with Phosphinothricin (PPT) and Basta. Plantlets were then screened by PCR based on the presence of cry1Ac and 14 cry1Ac positive plantlets were identified. Real-time quantitative PCR (RT-qPCR) revealed that the copy number of cry1Ac gene in the transgenic lines varied from 1 to 148. ELISA analysis showed that Cry1Ac protein levels in 7 transgenic lines ranged from 0.85 μg/FWg to 70.92 μg/FWg in leaves and 0.04 μg/FWg to 7.22 μg/FWg in stems, and negatively correlated to the rate of insect damage that ranged from 36.67% to 13.33%, respectively. Agronomic traits of six transgenic sugarcane lines with medium copy numbers were similar to the non-transgenic parental line. However, phenotype was poor in lines with high or low copy numbers. Compared to the non-transgenic control plants, all transgenic lines with medium copy numbers had relatively equal or lower sucrose yield and significantly improved sugarcane borer resistance, which lowered susceptibility to damage by insects. This suggests that the transgenic sugarcane lines harboring medium copy numbers of the cry1Ac gene may have significantly higher resistance to sugarcane borer but the sugarcane yield in these lines is similar to the non-transgenic control thus making them superior to the control lines.

  12. Transgenic soybean overexpressing GmSAMT1 exhibits resistance to multiple-HG types of soybean cyst nematode Heterodera glycines.

    PubMed

    Lin, Jingyu; Mazarei, Mitra; Zhao, Nan; Hatcher, Catherine N; Wuddineh, Wegi A; Rudis, Mary; Tschaplinski, Timothy J; Pantalone, Vincent R; Arelli, Prakash R; Hewezi, Tarek; Chen, Feng; Stewart, Charles Neal

    2016-11-01

    Soybean (Glycine max (L.) Merr.) salicylic acid methyl transferase (GmSAMT1) catalyses the conversion of salicylic acid to methyl salicylate. Prior results showed that when GmSAMT1 was overexpressed in transgenic soybean hairy roots, resistance is conferred against soybean cyst nematode (SCN), Heterodera glycines Ichinohe. In this study, we produced transgenic soybean overexpressing GmSAMT1 and characterized their response to various SCN races. Transgenic plants conferred a significant reduction in the development of SCN HG type 1.2.5.7 (race 2), HG type 0 (race 3) and HG type 2.5.7 (race 5). Among transgenic lines, GmSAMT1 expression in roots was positively associated with SCN resistance. In some transgenic lines, there was a significant decrease in salicylic acid titer relative to control plants. No significant seed yield differences were observed between transgenics and control soybean plants grown in one greenhouse with 22 °C day/night temperature, whereas transgenic soybean had higher yield than controls grown a warmer greenhouse (27 °C day/23 °C night) temperature. In a 1-year field experiment in Knoxville, TN, there was no significant difference in seed yield between the transgenic and nontransgenic soybean under conditions with negligible SCN infection. We hypothesize that GmSAMT1 expression affects salicylic acid biosynthesis, which, in turn, attenuates SCN development, without negative consequences to soybean yield or other morphological traits. Thus, we conclude that GmSAMT1 overexpression confers broad resistance to multiple SCN races, which would be potentially applicable to commercial production.

  13. Transgenic soybean overexpressing GmSAMT1 exhibits resistance to multiple-HG types of soybean cyst nematode Heterodera glycines

    DOE PAGES

    Lin, Jingyu; Mazarei, Mitra; Zhao, Nan; ...

    2016-05-23

    Soybean (Glycine max (L.) Merr.) salicylic acid methyl transferase (GmSAMT1) catalyses the conversion of salicylic acid to methyl salicylate. Prior results showed that when GmSAMT1 was overexpressed in transgenic soybean hairy roots, resistance is conferred against soybean cyst nematode (SCN), Heterodera glycines Ichinohe. In this study, we produced transgenic soybean overexpressing GmSAMT1 and characterized their response to various SCN races. Transgenic plants conferred a significant reduction in the development of SCN HG type 1.2.5.7 (race 2), HG type 0 (race 3) and HG type 2.5.7 (race 5). Among transgenic lines, GmSAMT1 expression in roots was positively associated with SCN resistance.more » In some transgenic lines, there was a significant decrease in salicylic acid titer relative to control plants. No significant seed yield differences were observed between transgenics and control soybean plants grown in one greenhouse with 22 °C day/night temperature, whereas transgenic soybean had higher yield than controls grown a warmer greenhouse (27 °C day/23 °C night) temperature. In a 1-year field experiment in Knoxville, TN, there was no significant difference in seed yield between the transgenic and nontransgenic soybean under conditions with negligible SCN infection. We hypothesize that GmSAMT1 expression affects salicylic acid biosynthesis, which, in turn, attenuates SCN development, without negative consequences to soybean yield or other morphological traits. Furthermore, we conclude that GmSAMT1 overexpression confers broad resistance to multiple SCN races, which would be potentially applicable to commercial production.« less

  14. Multidrug-resistant hela cells overexpressing MRP1 exhibit sensitivity to cell killing by hyperthermia: Interactions with etoposide

    SciTech Connect

    Souslova, Tatiana; Averill-Bates, Diana A. . E-mail: averill.diana@uqam.ca

    2004-12-01

    Purpose: Multidrug resistance (MDR) remains one of the primary obstacles in cancer chemotherapy and often involves overexpression of drug efflux transporters such as P-glycoprotein and multidrug resistance protein 1 (MRP1). Regional hyperthermia is undergoing clinical investigation in combination with chemotherapy or radiotherapy. This study evaluates whether hyperthermia can reverse MDR mediated by MRP1 in human cervical adenocarcinoma (HeLa) cells. Methods and materials: Cytotoxicity of hyperthermia and/or etoposide was evaluated using sulforhodamine-B in HeLa cells overexpressing MRP1 and their drug-sensitive counterparts. Glutathione, glutathione peroxidase (GPx), and glutathione S-transferase (GST) were quantified by spectrophotometry. GST isoenzymes were quantified by immunodetection. Caspase activation was evaluated by fluorometry and chromatin condensation by fluorescence microscopy using Hoechst 33258. Necrosis was determined using propidium iodide. Results: The major finding is that HeLa and HeLaMRP cells are both sensitive to cytotoxicity of hyperthermia (41-45 deg C). Hyperthermia induced activation of caspase 3 and chromatin condensation. Although total levels of cell killing were similar, there was a switch from apoptotic to necrotic cell death in MDR cells. This could be explained by decreased glutathione and GPx in MDR cells. MDR cells also contained very low levels of GST and were resistant to etoposide-induced apoptosis. Hyperthermia caused a modest increase in etoposide-induced apoptosis in HeLa and HeLaMRP cells, which required appropriate heat-drug scheduling. Conclusions: Hyperthermia could be useful in eliminating MDR cells that overexpress MRP1.

  15. Transgenic Brassica juncea plants expressing MsrA1, a synthetic cationic antimicrobial peptide, exhibit resistance to fungal phytopathogens.

    PubMed

    Rustagi, Anjana; Kumar, Deepak; Shekhar, Shashi; Yusuf, Mohd Aslam; Misra, Santosh; Sarin, Neera Bhalla

    2014-06-01

    Cationic antimicrobial peptides (CAPs) have shown potential against broad spectrum of phytopathogens. Synthetic versions with desirable properties have been modeled on these natural peptides. MsrA1 is a synthetic chimera of cecropin A and melittin CAPs with antimicrobial properties. We generated transgenic Brassica juncea plants expressing the msrA1 gene aimed at conferring fungal resistance. Five independent transgenic lines were evaluated for resistance to Alternaria brassicae and Sclerotinia sclerotiorum, two of the most devastating pathogens of B. juncea crops. In vitro assays showed inhibition by MsrA1 of Alternaria hyphae growth by 44-62 %. As assessed by the number and size of lesions and time taken for complete leaf necrosis, the Alternaria infection was delayed and restricted in the transgenic plants with the protection varying from 69 to 85 % in different transgenic lines. In case of S. sclerotiorum infection, the lesions were more severe and spread profusely in untransformed control compared with transgenic plants. The sclerotia formed in the stem of untransformed control plants were significantly more in number and larger in size than those present in the transgenic plants where disease protection of 56-71.5 % was obtained. We discuss the potential of engineering broad spectrum biotic stress tolerance by transgenic expression of CAPs in crop plants.

  16. Transgenic rice plants expressing synthetic cry2AX1 gene exhibits resistance to rice leaffolder (Cnaphalocrosis medinalis).

    PubMed

    Manikandan, R; Balakrishnan, N; Sudhakar, D; Udayasuriyan, V

    2016-06-01

    Bacillus thuringiensis is a major source of insecticidal genes imparting insect resistance in transgenic plants. Level of expression of transgenes in transgenic plants is important to achieve desirable level of resistance against target insects. In order to achieve desirable level of expression, rice chloroplast transit peptide sequence was fused with synthetic cry2AX1 gene to target its protein in chloroplasts. Sixteen PCR positive lines of rice were generated by Agrobacterium mediated transformation using immature embryos. Southern blot hybridization analysis of T0 transgenic plants confirmed the integration of cry2AX1 gene in two to five locations of rice genome and ELISA demonstrated its expression. Concentration of Cry2AX1 in transgenic rice events ranged 5.0-120 ng/g of fresh leaf tissue. Insect bioassay of T0 transgenic rice plants against neonate larvae of rice leaffolder showed larval mortality ranging between 20 and 80 % in comparison to control plant. Stable inheritance and expression of cry2AX1 gene was demonstrated in T1 progenies through Southern and ELISA. In T1 progenies, the highest concentration of Cry2AX1 and mortality of rice leaffolder larvae were recorded as 150 ng/g of fresh leaf tissue and 80 %, respectively. The Cry2AX1 expression even at a very low concentration (120-150 ng/g) in transgenic rice plants was found effective against rice leaffolder larvae.

  17. Bell and banana pepper exhibit mature-plant resistance to tomato spotted wilt Tospovirus transmitted by Frankliniella fusca (Thysanoptera: Thripidae).

    PubMed

    Beaudoin, A L P; Kahn, N D; Kennedy, G G

    2009-02-01

    Tomato spotted wilt virus (family Bunyaviridae, genus Tospovirus, TSWV) causes annual economic losses in pepper, Capsicum annuum L., across the southern United States and is transmitted by several species of thrips, including the tobacco thrips, Frankliniella fusca (Hinds). Reduced virus transmission and symptom severity as plant age increases is known as mature-plant resistance. TSWV transmission to pepper plants was examined in three and four age classes in field and greenhouse trials, respectively. In the field trial, 'Camelot' bell pepper plants were exposed to potentially viruliferous F. fusca 37, 51, or 65 d postsowing. Two greenhouse trials of Camelot bell and one trial each of 'Bounty' and 'Pageant' banana pepper plants were exposed to potentially viruliferous F. fusca, 43, 57, 71, or 85; 48, 62, 75, or 90; 42, 56, 70, or 84; and 43, 57, 71, or 85 d postsowing, respectively. Linear and hyperbolic regressions of percentage of infected plants per block on days postsowing indicated mature-plant resistance in all trials. All models were significant, but hyperbolic curves better fit the data than linear models. Hyperbolic models were used to calculate the number of days posttransplant at which a 50% decrease from the predicted percentage of infected plants at transplant age (42 d postsowing) was expected. This was referred to as days posttransplant-50 (DPT50). DPRT50 occurred within 9 days posttransplant age for all trials, indicating that early TSWV management in pepper is critical.

  18. Cry3Bb1-Resistant Western Corn Rootworm, Diabrotica virgifera virgifera (LeConte) Does Not Exhibit Cross-Resistance to DvSnf7 dsRNA

    PubMed Central

    Khajuria, Chitvan; Pleau, Michael; Ilagan, Oliver; Chen, Mao; Jiang, Changjian; Price, Paula; McNulty, Brian; Clark, Thomas; Head, Graham

    2017-01-01

    Background and Methodology There is a continuing need to express new insect control compounds in transgenic maize against western corn rootworm, Diabrotica virgifera virgifera (LeConte) (WCR). In this study three experiments were conducted to determine cross-resistance between the new insecticidal DvSnf7 dsRNA, and Bacillus thuringiensis (Bt) Cry3Bb1; used to control WCR since 2003, with field-evolved resistance being reported. Laboratory susceptible and Cry3Bb1-resistant WCR were evaluated against DvSnf7 dsRNA in larval diet-incorporation bioassays. Additionally, the susceptibility of seven field and one field-derived WCR populations to DvSnf7 (and Cry3Bb1) was assessed in larval diet-overlay bioassays. Finally, beetle emergence of laboratory susceptible and Cry3Bb1-resistant WCR was evaluated with maize plants in the greenhouse expressing Cry3Bb1, Cry34Ab1/Cry35Ab1, or DvSnf7 dsRNA singly, or in combination. Principal Findings and Conclusions The Cry3Bb1-resistant colony had slight but significantly (2.7-fold; P<0.05) decreased susceptibility to DvSnf7 compared to the susceptible colony, but when repeated using a field-derived WCR population selected for reduced Cry3Bb1 susceptibility, there was no significant difference (P<0.05) in DvSnf7 susceptibility compared to that same susceptible population. Additionally, this 2.7-fold difference in susceptibility falls within the range of DvSnf7 susceptibility among the seven field populations tested. Additionally, there was no correlation between susceptibility to DvSnf7 and Cry3Bb1 for all populations evaluated. In greenhouse studies, there were no significant differences (P<0.05) between beetle emergence of susceptible and Cry3Bb1-resistant colonies on DvSnf7 and Cry34Ab1/Cry35Ab1, and between DvSnf7 and MON 87411 (DvSnf7 + Cry3Bb1) for the Cry3Bb1-resistant colony. These results demonstrate no cross-resistance between DvSnf7 and Cry3Bb1 against WCR. Therefore, pyramiding DvSnf7 with Bt proteins such as Cry3Bb1 and

  19. Mice deficient in Group VIB phospholipase A2 (iPLA2γ) exhibit relative resistance to obesity and metabolic abnormalities induced by a Western diet

    PubMed Central

    Song, Haowei; Wohltmann, Mary; Bao, Shunzhong; Ladenson, Jack H.; Semenkovich, Clay F.

    2010-01-01

    Phospholipases A2 (PLA2) play important roles in metabolic processes, and the Group VI PLA2 family is comprised of intracellular enzymes that do not require Ca2+ for catalysis. Mice deficient in Group VIA PLA2 (iPLA2β) develop more severe glucose intolerance than wild-type (WT) mice in response to dietary stress. Group VIB PLA2 (iPLA2γ) is a related enzyme distributed in membranous organelles, including mitochondria, and iPLA2γ knockout (KO) mice exhibit altered mitochondrial morphology and function. We have compared metabolic responses of iPLA2γ-KO and WT mice fed a Western diet (WD) with a high fat content. We find that KO mice are resistant to WD-induced increases in body weight and adiposity and in blood levels of cholesterol, glucose, and insulin, even though WT and KO mice exhibit similar food consumption and dietary fat digestion and absorption. KO mice are also relatively resistant to WD-induced insulin resistance, glucose intolerance, and altered patterns of fat vs. carbohydrate fuel utilization. KO skeletal muscle exhibits impaired mitochondrial β-oxidation of fatty acids, as reflected by accumulation of larger amounts of long-chain acylcarnitine (LCAC) species in KO muscle and liver compared with WT in response to WD feeding. This is associated with increased urinary excretion of LCAC and much reduced deposition of triacylglycerols in liver by WD-fed KO compared with WT mice. The iPLA2γ-deficient genotype thus results in a phenotype characterized by impaired mitochondrial oxidation of fatty acids and relative resistance to the metabolic abnormalities induced by WD. PMID:20179248

  20. Characterization and Genetic Analysis of Rice Mutant crr1 Exhibiting Compromised Non-host Resistance to Puccinia striiformis f. sp. tritici (Pst)

    PubMed Central

    Zhao, Jing; Yang, Yuheng; Yang, Donghe; Cheng, Yulin; Jiao, Min; Zhan, Gangming; Zhang, Hongchang; Wang, Junyi; Zhou, Kai; Huang, Lili; Kang, Zhensheng

    2016-01-01

    Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most devastating diseases of wheat in China. Rapid change to virulence following release of resistant cultivars necessitates ongoing discovery and exploitation of new resistance resources. Considerable effort has been directed at non-host resistance (NHR) which is believed to be durable. In the present study we identified rice mutant crr1 (compromised resistance to rust 1) that exhibited compromised NHR to Pst. Compared with wild type rice variety Nipponbare, crr1 mutant displayed a threefold increase in penetration rate by Pst, and enhanced hyphal growth. The pathogen also developed haustoria in crr1 mesophyll cells, but failed to sporulate. The response to the adapted rice pathogen Magnaporthe oryzae was unchanged in crr1 relative to the wild type. Several defense-related genes involved in the SA- and JA-mediated defense pathways response and in phytoalexin synthesis (such as OsPR1a, OsLOX1, and OsCPS4) were more rapidly and strongly induced in infected crr1 leaves than in the wild type, suggesting that other layers of defense are still in effect. Genetic analysis and mapping located the mutant loci at a region between markers ID14 and RM25792, which cover about 290 kb genome sequence on chromosome 10. Further fine mapping and cloning of the locus should provide further insights into NHR to rust fungi in rice, and may reveal new strategies for improving rust resistance in wheat. PMID:27965705

  1. Cunninghamella bertholletiae exhibits increased resistance to human neutrophils with or without antifungal agents as compared to Rhizopus spp.

    PubMed

    Simitsopoulou, Maria; Georgiadou, Elpiniki; Walsh, Thomas J; Roilides, Emmanuel

    2010-08-01

    Among Zygomycetes, Cunninghamella bertholletiae occurs less frequently as the etiologic agent of human disease but causes more aggressive, refractory, and fatal infections despite antifungal therapy. Little is known about the differential innate host response against Cunninghamella and other Zygomycetes in the presence of antifungal agents. We therefore studied the activity of human neutrophils (PMNs) alone or in combination with caspofungin, posaconazole (PSC), and voriconazole (VRC) against hyphae of Rhizopus oryzae, Rhizopus microsporus and C. bertholletiae. Hyphal damage was measured by XTT metabolic assay and release of IL-6, IL-8 and TNF-alpha from PMNs by ELISA. Cunninghamella bertholletiae was more resistant to PMN-induced hyphal damage than either Rhizopus spp. at effector:target (E:T) ratios of 1:1, 5:1 and 10:1 (P < 0.05). The hyphal damage caused by caspofungin at 0.1 microg/ml or PSC and VRC at 0.5 microg/ml with C. bertholletiae and R. oryzae and by caspofungin against R. microsporus ranged from 18-29%. The PMN-induced hyphal damage was not modulated by combination with antifungal agents. Cunninghamella bertholletiae induced significantly decreased IL-8 (P < 0.05), but increased TNF-alpha release from PMNs compared to both Rhizopus spp. (P < 0.01). No IL-6 was released from PMNs exposed to the three Zygomycetes. In comparison to R. oryzae and R. microsporus, C. bertholletiae is more resistant to PMN-induced hyphal damage with or without antifungal therapy and is more capable of suppressing release of IL-8.

  2. Biofilm-Forming Methicillin-Resistant Staphylococcus aureus Survive in Kupffer Cells and Exhibit High Virulence in Mice

    PubMed Central

    Oyama, Takuto; Miyazaki, Motoyasu; Yoshimura, Michinobu; Takata, Tohru; Ohjimi, Hiroyuki; Jimi, Shiro

    2016-01-01

    Although Staphylococcus aureus is part of the normal body flora, heavy usage of antibiotics has resulted in the emergence of methicillin-resistant strains (MRSA). MRSA can form biofilms and cause indwelling foreign body infections, bacteremia, soft tissue infections, endocarditis, and osteomyelitis. Using an in vitro assay, we screened 173 clinical blood isolates of MRSA and selected 20 high-biofilm formers (H-BF) and low-biofilm formers (L-BF). These were intravenously administered to mice and the general condition of mice, the distribution of bacteria, and biofilm in the liver, lung, spleen, and kidney were investigated. MRSA count was the highest in the liver, especially within Kupffer cells, which were positive for acid polysaccharides that are associated with intracellular biofilm. After 24 h, the general condition of the mice worsened significantly in the H-BF group. In the liver, bacterial deposition and aggregation and the biofilm-forming spot number were all significantly greater for H-BF group than for L-BF. CFU analysis revealed that bacteria in the H-BF group survived for long periods in the liver. These results indicate that the biofilm-forming ability of MRSA is a crucial factor for intracellular persistence, which could lead to chronic infections. PMID:27376326

  3. Transgenic tomato plants overexpressing tyramine N-hydroxycinnamoyltransferase exhibit elevated hydroxycinnamic acid amide levels and enhanced resistance to Pseudomonas syringae.

    PubMed

    Campos, Laura; Lisón, Purificación; López-Gresa, María Pilar; Rodrigo, Ismael; Zacarés, Laura; Conejero, Vicente; Bellés, José María

    2014-10-01

    Hydroxycinnamic acid amides (HCAA) are secondary metabolites involved in plant development and defense that have been widely reported throughout the plant kingdom. These phenolics show antioxidant, antiviral, antibacterial, and antifungal activities. Hydroxycinnamoyl-CoA:tyramine N-hydroxycinnamoyl transferase (THT) is the key enzyme in HCAA synthesis and is induced in response to pathogen infection, wounding, or elicitor treatments, preceding HCAA accumulation. We have engineered transgenic tomato plants overexpressing tomato THT. These plants displayed an enhanced THT gene expression in leaves as compared with wild type (WT) plants. Consequently, leaves of THT-overexpressing plants showed a higher constitutive accumulation of the amide coumaroyltyramine (CT). Similar results were found in flowers and fruits. Moreover, feruloyltyramine (FT) also accumulated in these tissues, being present at higher levels in transgenic plants. Accumulation of CT, FT and octopamine, and noradrenaline HCAA in response to Pseudomonas syringae pv. tomato infection was higher in transgenic plants than in the WT plants. Transgenic plants showed an enhanced resistance to the bacterial infection. In addition, this HCAA accumulation was accompanied by an increase in salicylic acid levels and pathogenesis-related gene induction. Taken together, these results suggest that HCAA may play an important role in the defense of tomato plants against P. syringae infection.

  4. Canine Mammary Cancer Stem Cells are Radio- and Chemo- Resistant and Exhibit an Epithelial-Mesenchymal Transition Phenotype.

    PubMed

    Pang, Lisa Y; Cervantes-Arias, Alejandro; Else, Rod W; Argyle, David J

    2011-03-30

    Canine mammary carcinoma is the most common cancer among female dogs and is often fatal due to the development of distant metastases. In humans, solid tumors are made up of heterogeneous cell populations, which perform different roles in the tumor economy. A small subset of tumor cells can hold or acquire stem cell characteristics, enabling them to drive tumor growth, recurrence and metastasis. In veterinary medicine, the molecular drivers of canine mammary carcinoma are as yet undefined. Here we report that putative cancer stem cells (CSCs) can be isolated form a canine mammary carcinoma cell line, REM134. We show that these cells have an increased ability to form tumorspheres, a characteristic of stem cells, and that they express embryonic stem cell markers associated with pluripotency. Moreover, canine CSCs are relatively resistant to the cytotoxic effects of common chemotherapeutic drugs and ionizing radiation, indicating that failure of clinical therapy to eradicate canine mammary cancer may be due to the survival of CSCs. The epithelial to mesenchymal transition (EMT) has been associated with cancer invasion, metastasis, and the acquisition of stem cell characteristics. Our results show that canine CSCs predominantly express mesenchymal markers and are more invasive than parental cells, indicating that these cells have a mesenchymal phenotype. Furthermore, we show that canine mammary cancer cells can be induced to undergo EMT by TGFβ and that these cells have an increased ability to form tumorspheres. Our findings indicate that EMT induction can enrich for cells with CSC properties, and provide further insight into canine CSC biology.

  5. Carbapenem-Resistant Klebsiella pneumoniae Strains Exhibit Diversity in Aminoglycoside-Modifying Enzymes, Which Exert Differing Effects on Plazomicin and Other Agents

    PubMed Central

    Almaghrabi, Reem; Doi, Yohei; Hao, Binghua; Chen, Liang; Shields, Ryan K.; Press, Ellen G.; Iovine, Nicole M.; Townsend, Bethany M.; Wagener, Marilyn M.; Kreiswirth, Barry; Nguyen, M. Hong

    2014-01-01

    We measured in vitro activity of plazomicin, a next-generation aminoglycoside, and other aminoglycosides against 50 carbapenem-resistant Klebsiella pneumoniae strains from two centers and correlated the results with the presence of various aminoglycoside-modifying enzymes (AMEs). Ninety-four percent of strains were sequence type 258 (ST258) clones, which exhibited 5 ompK36 genotypes; 80% and 10% of strains produced Klebsiella pneumoniae carbapenemase 2 (KPC-2) and KPC-3, respectively. Ninety-eight percent of strains possessed AMEs, including AAC(6′)-Ib (98%), APH(3′)-Ia (56%), AAC(3)-IV (38%), and ANT(2″)-Ia (2%). Gentamicin, tobramycin, and amikacin nonsusceptibility rates were 40, 98, and 16%, respectively. Plazomicin MICs ranged from 0.25 to 1 μg/ml. Tobramycin and plazomicin MICs correlated with gentamicin MICs (r = 0.75 and 0.57, respectively). Plazomicin exerted bactericidal activity against 17% (1× MIC) and 94% (4× MIC) of strains. All strains with AAC(6′)-Ib were tobramycin-resistant; 16% were nonsusceptible to amikacin. AAC(6′)-Ib combined with another AME was associated with higher gentamicin, tobramycin, and plazomicin MICs than AAC(6′)-Ib alone (P = 0.01, 0.0008, and 0.046, respectively). The presence of AAC(3)-IV in a strain was also associated with higher gentamicin, tobramycin, and plazomicin MICs (P = 0.0006, P < 0.0001, and P = 0.01, respectively). The combination of AAC(6′)-Ib and another AME, the presence of AAC(3)-IV, and the presence of APH(3′)-Ia were each associated with gentamicin resistance (P = 0.0002, 0.003, and 0.01, respectively). In conclusion, carbapenem-resistant K. pneumoniae strains (including ST258 clones) exhibit highly diverse antimicrobial resistance genotypes and phenotypes. Plazomicin may offer a treatment option against strains resistant to other aminoglycosides. The development of molecular assays that predict antimicrobial responses among carbapenem-resistant K. pneumoniae strains should be a research

  6. A spontaneous mutation in kdsD, a biosynthesis gene for 3 Deoxy-D-manno-Octulosonic Acid, occurred in a ciprofloxacin resistant strain of Francisella tularensis and caused a high level of attenuation in murine models of tularemia.

    PubMed

    Chance, Taylor; Chua, Jennifer; Toothman, Ronald G; Ladner, Jason T; Nuss, Jonathan E; Raymond, Jo Lynne; Biot, Fabrice V; Demons, Samandra; Miller, Lynda; Halasohoris, Stephanie; Mou, Sherry; Koroleva, Galina; Lovett, Sean; Palacios, Gustavo; Vietri, Nicholas J; Worsham, Patricia L; Cote, Christopher K; Kijek, Todd M; Bozue, Joel A

    2017-01-01

    Francisella tularensis, a gram-negative facultative intracellular bacterial pathogen, is the causative agent of tularemia and able to infect many mammalian species, including humans. Because of its ability to cause a lethal infection, low infectious dose, and aerosolizable nature, F. tularensis subspecies tularensis is considered a potential biowarfare agent. Due to its in vitro efficacy, ciprofloxacin is one of the antibiotics recommended for post-exposure prophylaxis of tularemia. In order to identify therapeutics that will be efficacious against infections caused by drug resistant select-agents and to better understand the threat, we sought to characterize an existing ciprofloxacin resistant (CipR) mutant in the Schu S4 strain of F. tularensis by determining its phenotypic characteristics and sequencing the chromosome to identify additional genetic alterations that may have occurred during the selection process. In addition to the previously described genetic alterations, the sequence of the CipR mutant strain revealed several additional mutations. Of particular interest was a frameshift mutation within kdsD which encodes for an enzyme necessary for the production of 3-Deoxy-D-manno-Octulosonic Acid (KDO), an integral component of the lipopolysaccharide (LPS). A kdsD mutant was constructed in the Schu S4 strain. Although it was not resistant to ciprofloxacin, the kdsD mutant shared many phenotypic characteristics with the CipR mutant, including growth defects under different conditions, sensitivity to hydrophobic agents, altered LPS profiles, and attenuation in multiple models of murine tularemia. This study demonstrates that the KdsD enzyme is essential for Francisella virulence and may be an attractive therapeutic target for developing novel medical countermeasures.

  7. A spontaneous mutation in kdsD, a biosynthesis gene for 3 Deoxy-D-manno-Octulosonic Acid, occurred in a ciprofloxacin resistant strain of Francisella tularensis and caused a high level of attenuation in murine models of tularemia

    PubMed Central

    Chance, Taylor; Toothman, Ronald G.; Nuss, Jonathan E.; Raymond, Jo Lynne; Biot, Fabrice V.; Demons, Samandra; Miller, Lynda; Halasohoris, Stephanie; Mou, Sherry; Koroleva, Galina; Lovett, Sean; Palacios, Gustavo; Vietri, Nicholas J.; Worsham, Patricia L.; Cote, Christopher K.; Kijek, Todd M.; Bozue, Joel A.

    2017-01-01

    Francisella tularensis, a gram–negative facultative intracellular bacterial pathogen, is the causative agent of tularemia and able to infect many mammalian species, including humans. Because of its ability to cause a lethal infection, low infectious dose, and aerosolizable nature, F. tularensis subspecies tularensis is considered a potential biowarfare agent. Due to its in vitro efficacy, ciprofloxacin is one of the antibiotics recommended for post-exposure prophylaxis of tularemia. In order to identify therapeutics that will be efficacious against infections caused by drug resistant select-agents and to better understand the threat, we sought to characterize an existing ciprofloxacin resistant (CipR) mutant in the Schu S4 strain of F. tularensis by determining its phenotypic characteristics and sequencing the chromosome to identify additional genetic alterations that may have occurred during the selection process. In addition to the previously described genetic alterations, the sequence of the CipR mutant strain revealed several additional mutations. Of particular interest was a frameshift mutation within kdsD which encodes for an enzyme necessary for the production of 3-Deoxy-D-manno-Octulosonic Acid (KDO), an integral component of the lipopolysaccharide (LPS). A kdsD mutant was constructed in the Schu S4 strain. Although it was not resistant to ciprofloxacin, the kdsD mutant shared many phenotypic characteristics with the CipR mutant, including growth defects under different conditions, sensitivity to hydrophobic agents, altered LPS profiles, and attenuation in multiple models of murine tularemia. This study demonstrates that the KdsD enzyme is essential for Francisella virulence and may be an attractive therapeutic target for developing novel medical countermeasures. PMID:28328947

  8. Mutations in aarE, the ubiA homolog of Providencia stuartii, result in high-level aminoglycoside resistance and reduced expression of the chromosomal aminoglycoside 2'-N-acetyltransferase.

    PubMed

    Paradise, M R; Cook, G; Poole, R K; Rather, P N

    1998-04-01

    The aarE1 allele was identified on the basis of the resulting phenotype of increased aminoglycoside resistance. The aarE1 mutation also resulted in a small-colony phenotype and decreased levels of aac(2')-Ia mRNA. The deduced AarE gene product displayed 61% amino acid identity to the Escherichia coli UbiA protein, an octaprenyltransferase required for the second step of ubiquinone biosynthesis. Complementation experiments in both Providencia stuartii and E. coli demonstrated that aarE and ubiA are functionally equivalent.

  9. Characterization of a Nosocomial Outbreak Caused by a Multiresistant Acinetobacter baumannii Strain with a Carbapenem-Hydrolyzing Enzyme: High-Level Carbapenem Resistance in A. baumannii Is Not Due Solely to the Presence of β-Lactamases

    PubMed Central

    Bou, Germán; Cerveró, Gonzalo; Domínguez, M. Angeles; Quereda, Carmen; Martínez-Beltrán, Jesús

    2000-01-01

    From February to November 1997, 29 inpatients at Ramón y Cajal Hospital, Madrid, Spain, were determined to be either colonized or infected with imipenem- and meropenem-resistant Acinetobacter baumannii (IMRAB) strains (MICs, 128 to 256 μg/ml). A wide antibiotic multiresistance profile was observed with IMRAB strains. For typing IMRAB isolates, pulsed-field gel electrophoresis was used. For comparative purposes, 30 imipenem- and meropenem-susceptible A. baumannii (IMSAB) strains isolated before, during, and after the outbreak were included in this study. The molecular-typing results showed that the outbreak was caused by a single IMRAB strain (genotype A). By cloning experiments we identified a class D β-lactamase (OXA-24) encoded in the chromosomal DNA of this IMRAB strain which showed carbapenem hydrolysis. Moreover, the outer membrane profile of the IMRAB strain showed a reduction in the expression of two porins at 22 and 33 kDa when compared with genetically related IMSAB isolates. In addition no efflux mechanisms were identified in the IMRAB strains. In summary, we report here the molecular characterization of a nosocomial outbreak caused by one multiresistant A. baumannii epidemic strain that harbors a carbapenem-hydrolyzing enzyme. Although alterations in the penicillin-binding proteins cannot be ruled out, the reduction in the expression of two porins and the presence of this OXA-derived β-lactamase are involved in the carbapenem resistance of the epidemic nosocomial IMRAB strain. PMID:10970374

  10. Peptidomimetic furin inhibitor MI-701 in combination with oseltamivir and ribavirin efficiently blocks propagation of highly pathogenic avian influenza viruses and delays high level oseltamivir resistance in MDCK cells.

    PubMed

    Lu, Yinghui; Hardes, Kornelia; Dahms, Sven O; Böttcher-Friebertshäuser, Eva; Steinmetzer, Torsten; Than, Manuel E; Klenk, Hans-Dieter; Garten, Wolfgang

    2015-08-01

    Antiviral medication is used for the treatment of severe influenza infections, of which the neuraminidase inhibitors (NAIs) are the most effective drugs, approved so far. Here, we investigated the antiviral efficacy of the peptidomimetic furin inhibitor MI-701 in combination with oseltamivir carboxylate and ribavirin against the infection of highly pathogenic avian influenza viruses (HPAIV) that are activated by the host protease furin. Cell cultures infected with the strains A/Thailand/1(KAN-1)/2004 (H5N1) and A/FPV/Rostock/1934 (H7N1) were treated with each agent alone, or in double and triple combinations. MI-701 alone achieved a concentration-dependent reduction of virus propagation. Double treatment of MI-701 with oseltamivir carboxylate and triple combination with ribavirin showed synergistic inhibition and a pronounced delay of virus propagation. MI-701 resistant mutants were not observed. Emergence of NA mutation H275Y conferring high oseltamivir resistance was significantly delayed in the presence of MI-701. Our data indicate that combination with a potent furin inhibitor significantly enhances the therapeutic efficacy of conventional antivirals drugs against HPAIV infection.

  11. Exhibiting Lives

    ERIC Educational Resources Information Center

    Golden, Deborah; Elbaz-Luwisch, Freema

    2007-01-01

    This paper examines some of the dilemmas that accompany the emergence of the personal voice in scholarly work, by taking a close, grounded look at the way in which these unfolded in a specific academic course. As part of the course, entitled "A cultural approach to the life cycle", students were asked to participate in a group exhibition in which…

  12. Museum Exhibit

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A TSP from NASA Tech Briefs provided the solution to an electrical problem at a Florida museum. When a model train would not start without a jerk, a Marshall Space Flight Center development called pulse width control was adapted. The new circuit enables the train to start smoothly and reduces construction and maintenance costs. The same technology is also used in another hands-on exhibit. Applications of other TSPs are anticipated.

  13. Lead iron phosphate glass as a containment medium for disposal of high-level nuclear waste

    DOEpatents

    Boatner, Lynn A.; Sales, Brian C.

    1989-01-01

    Lead-iron phosphate glasses containing a high level of Fe.sub.2 O.sub.3 for use as a storage medium for high-level radioactive nuclear waste. By combining lead-iron phosphate glass with various types of simulated high-level nuclear waste, a highly corrosion resistant, homogeneous, easily processed glass can be formed. For corroding solutions at 90.degree. C., with solution pH values in the range between 5 and 9, the corrosion rate of the lead-iron phosphate nuclear waste glass is at least 10.sup.2 to 10.sup.3 times lower than the corrosion rate of a comparable borosilicate nuclear waste glass. The presence of Fe.sub.2 O.sub.3 in forming the lead-iron phosphate glass is critical. Lead-iron phosphate nuclear waste glass can be prepared at temperatures as low as 800.degree. C., since they exhibit very low melt viscosities in the 800.degree. to 1050.degree. C. temperature range. These waste-loaded glasses do not readily devitrify at temperatures as high as 550.degree. C. and are not adversely affected by large doses of gamma radiation in H.sub.2 O at 135.degree. C. The lead-iron phosphate waste glasses can be prepared with minimal modification of the technology developed for processing borosilicate glass nuclear wasteforms.

  14. Outdoor Exhibits

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The National Data Buoy Center (NDBC) at the John C. Stennis Space Center has exhibits located in front of the Visitors Center. These boat-shaped buoys are moored in areas of the ocean that experience hostile environmental conditions. The instruments installed gather information and relay it to the National Weather Service by satellite. Nomad buoys are 20 feet long and weigh 13,900 pounds. They provide information on wind speed and direction, humidity levels, air and sea surface temperature and air pressure. U.S. Coast Guard ships transport buoys to their mooring sites.

  15. Young overweight and obese women with lower circulating osteocalcin concentrations exhibit higher insulin resistance and concentrations of C-reactive protein.

    PubMed

    Lucey, Alice J; Paschos, Georgios K; Thorsdottir, Inga; Martínéz, J Alfredo; Cashman, Kevin D; Kiely, Máireád

    2013-01-01

    The role of the skeleton in the regulation of energy metabolism in humans is not clear. This study investigates the hypothesis that biomarkers of bone turnover are associated with indices of glucose homeostasis and systemic inflammation in young adults. A cross-sectional study investigating the relationships between biomarkers of bone turnover (serum total and uncarboxylated osteocalcin, bone-specific alkaline phosphatase, C-telopeptide of type I collagen, urinary N-telopeptide of type I collagen) and glucose metabolism (fasting plasma glucose [FPG], insulin, insulin resistance [homeostatic model assessment of insulin resistance]), systemic inflammation (high-sensitivity C-reactive protein [hsCRP] and interleukin-6), adipokines (leptin and adiponectin), and body composition was conducted in 268 young, nondiabetic overweight and obese adults aged 20 to 40 years (116 men, 152 women; body mass index, 27.5-32.5 kg/m(2)). Data on diet, physical activity, serum 25-hydroxyvitamin D, and parathyroid hormone were also collected. In women, there was a stepwise increase in lean body mass (P < .05) and a decrease in serum hsCRP (P < .001) across tertiles of total osteocalcin. Multiple linear regression analysis showed significant inverse associations between total osteocalcin and FPG (β = -0.350; P = .016; 95% confidence interval [CI], -0.35 to -0.04), insulin (β = -0.455; P = .002; 95% CI, -1.9 to -0.46), and homeostatic model assessment of insulin resistance (β = -0.508; P = .001; 95% CI, -10.93 to -3.17) in women with total osteocalcin concentrations below the group median. Men in the lowest tertile of uncarboxylated osteocalcin had twice the concentration of hsCRP than did other men (P = .05). In this sample, women with less lean body mass had lower circulating total osteocalcin concentrations and exhibited higher FPG, insulin resistance, and hsCRP compared with their similarly sized counterparts, suggesting that associations between osteocalcin and systemic

  16. Design and membrane-disruption mechanism of charge-enriched AMPs exhibiting cell selectivity, high-salt resistance, and anti-biofilm properties.

    PubMed

    Han, Hyo Mi; Gopal, Ramamourthy; Park, Yoonkyung

    2016-02-01

    Cationic antimicrobial peptides (AMPs) are essential components of the innate immune system, offering protection against invading pathogenic bacteria. In nature, AMPs serve as antibiotics with broad-spectrum antimicrobial and anti-biofilm properties. However, low effective stability in high-salt environments and physiological instability in biological membranes limit the applicability of naturally occurring AMPs as novel therapeutics. We therefore designed short synthetic cationic peptides by substituting key residues in myxinidin, an AMP derived from the epidermal mucus of hagfish, with lysine (Lys, K), arginine (Arg, R), and tryptophan (Trp, W). The resultant myxinidin analogs exhibited strong antimicrobial activity against both Gram-positive and Gram-negative bacteria, including multidrug-resistant strains, even under high-salt conditions. Moreover, these peptides showed high binding affinity for both lipopolysaccharides and lipoteichoic acids and inhibited biofilm formation by most bacteria, but did not cause significant lysis of human red blood cells and were not cytotoxic to normal human keratinocytes. Circular dichroism analysis revealed that myxinidin and its analogs assumed α-helical or β-sheet structures within artificial liposomes and bacterial membranes. In addition, bacterial killing and membrane permeation experiments demonstrated that the myxinidin analogs permeated through bacterial membranes, leading to cytoplasmic disruption and cell death. Taken together, these findings suggest myxinidin analogs may be promising candidate antibiotic agents for therapeutic application against antibiotic-resistant bacteria.

  17. A Software Architecture for High Level Applications

    SciTech Connect

    Shen,G.

    2009-05-04

    A modular software platform for high level applications is under development at the National Synchrotron Light Source II project. This platform is based on client-server architecture, and the components of high level applications on this platform will be modular and distributed, and therefore reusable. An online model server is indispensable for model based control. Different accelerator facilities have different requirements for the online simulation. To supply various accelerator simulators, a set of narrow and general application programming interfaces is developed based on Tracy-3 and Elegant. This paper describes the system architecture for the modular high level applications, the design of narrow and general application programming interface for an online model server, and the prototype of online model server.

  18. High-Level Application Framework for LCLS

    SciTech Connect

    Chu, P; Chevtsov, S.; Fairley, D.; Larrieu, C.; Rock, J.; Rogind, D.; White, G.; Zalazny, M.; /SLAC

    2008-04-22

    A framework for high level accelerator application software is being developed for the Linac Coherent Light Source (LCLS). The framework is based on plug-in technology developed by an open source project, Eclipse. Many existing functionalities provided by Eclipse are available to high-level applications written within this framework. The framework also contains static data storage configuration and dynamic data connectivity. Because the framework is Eclipse-based, it is highly compatible with any other Eclipse plug-ins. The entire infrastructure of the software framework will be presented. Planned applications and plug-ins based on the framework are also presented.

  19. PAIRWISE BLENDING OF HIGH LEVEL WASTE (HLW)

    SciTech Connect

    CERTA, P.J.

    2006-02-22

    The primary objective of this study is to demonstrate a mission scenario that uses pairwise and incidental blending of high level waste (HLW) to reduce the total mass of HLW glass. Secondary objectives include understanding how recent refinements to the tank waste inventory and solubility assumptions affect the mass of HLW glass and how logistical constraints may affect the efficacy of HLW blending.

  20. High-level radioactive wastes. Supplement 1

    SciTech Connect

    McLaren, L.H.

    1984-09-01

    This bibliography contains information on high-level radioactive wastes included in the Department of Energy's Energy Data Base from August 1982 through December 1983. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number. 1452 citations.

  1. Overexpression of ShCYP51B and ShatrD in Sclerotinia homoeocarpa isolates exhibiting practical field resistance to a demethylation inhibitor fungicide.

    PubMed

    Hulvey, Jon; Popko, James T; Sang, Hyunkyu; Berg, Andrew; Jung, Geunhwa

    2012-09-01

    We investigated genetic factors that govern the reduced propiconazole sensitivity of Sclerotinia homoeocarpa field isolates collected during a 2-year field efficacy study on dollar spot disease of turf in five New England sites. These isolates displayed a >50-fold range of in vitro sensitivity to a sterol demethylation inhibitor (DMI) fungicide, propiconazole, making them ideal for investigations of genetic mechanisms of reduced DMI sensitivity. The CYP51 gene homolog in S. homoeocarpa (ShCYP51B), encoding the enzyme target of DMIs, is likely a minor genetic factor for reduced propiconazole sensitivity, since there were no differences in constitutive relative expression (RE) values and only 2-fold-higher induced RE values for insensitive than for sensitive isolate groups. Next, we mined RNA-Seq transcriptome data for additional genetic factors and found evidence for the overexpression of a homolog of Botrytis cinerea atrD (BcatrD), ShatrD, a known efflux transporter of DMI fungicides. The ShatrD gene showed much higher constitutive and induced RE values for insensitive isolates. Several polymorphisms were found upstream of ShatrD but were not definitively linked to overexpression. The screening of constitutive RE values of ShCYP51B and ShatrD in isolates from two golf courses that exhibited practical field resistance to propiconazole uncovered evidence for significant population-specific overexpression of both genes. However, linear regression demonstrated that the RE of ShatrD displays a more significant relationship with propiconazole sensitivity than that of ShCYP51B. In summary, our results suggest that efflux is a major determinant of the reduced DMI sensitivity of S. homoeocarpa genotypes in New England, which may have implications for the emergence of practical field resistance in this important turfgrass pathogen.

  2. BPR1K653, a Novel Aurora Kinase Inhibitor, Exhibits Potent Anti-Proliferative Activity in MDR1 (P-gp170)-Mediated Multidrug-Resistant Cancer Cells

    PubMed Central

    Cheung, Chun Hei Antonio; Lin, Wen-Hsing; Hsu, John Tsu-An; Hour, Tzyh-Chyuan; Yeh, Teng-Kuang; Ko, Shengkai; Lien, Tzu-Wen; Coumar, Mohane Selvaraj; Liu, Jin-Fen; Lai, Wen-Yang; Shiao, Hui-Yi; Lee, Tian-Ren; Hsieh, Hsing-Pang; Chang, Jang-Yang

    2011-01-01

    Background Over-expression of Aurora kinases promotes the tumorigenesis of cells. The aim of this study was to determine the preclinical profile of a novel pan-Aurora kinase inhibitor, BPR1K653, as a candidate for anti-cancer therapy. Since expression of the drug efflux pump, MDR1, reduces the effectiveness of various chemotherapeutic compounds in human cancers, this study also aimed to determine whether the potency of BPR1K653 could be affected by the expression of MDR1 in cancer cells. Principal Findings BPR1K653 specifically inhibited the activity of Aurora-A and Aurora-B kinase at low nano-molar concentrations in vitro. Anti-proliferative activity of BPR1K653 was evaluated in various human cancer cell lines. Results of the clonogenic assay showed that BPR1K653 was potent in targeting a variety of cancer cell lines regardless of the tissue origin, p53 status, or expression of MDR1. At the cellular level, BPR1K653 induced endo-replication and subsequent apoptosis in both MDR1-negative and MDR1-positive cancer cells. Importantly, it showed potent activity against the growth of xenograft tumors of the human cervical carcinoma KB and KB-derived MDR1-positive KB-VIN10 cells in nude mice. Finally, BPR1K653 also exhibited favorable pharmacokinetic properties in rats. Conclusions and Significance BPR1K653 is a novel potent anti-cancer compound, and its potency is not affected by the expression of the multiple drug resistant protein, MDR1, in cancer cells. Therefore, BPR1K653 is a promising anti-cancer compound that has potential for the management of various malignancies, particularly for patients with MDR1-related drug resistance after prolonged chemotherapeutic treatments. PMID:21887256

  3. BAC Transgenic Mice Expressing a Truncated Mutant Parkin Exhibit Age-dependent Hypokinetic Motor Deficits, Dopaminergic Neuron Degeneration, and Accumulation of Proteinase K-Resistant Alpha-Synuclein

    PubMed Central

    Lu, Xiao-Hong; Fleming, Sheila M.; Meurers, Bernhard; Ackerson, Larry C.; Mortazavi, Farzad; Lo, Victor; Hernandez, Daniela; Sulzer, David; Jackson, George R.; Maidment, Nigel T.; Chesselet, Marie-Francoise; Yang, X. William

    2009-01-01

    Summary Recessive mutations in parkin are the most common cause of familial early onset Parkinson's disease (PD). Recent studies suggest that certain parkin mutants may exert dominant toxic effects to cultured cells and such dominant toxicity can lead to progressive dopaminergic (DA) neuron degeneration in Drosophila. To explore whether mutant parkin could exert similar pathogenic effects to mammalian DA neurons in vivo, we developed a Bacterial Artificial Chromosome (BAC) transgenic mouse model expressing a C-terminal truncated human mutant parkin (Parkin-Q311X) in DA neurons driven by a dopamine transporter promoter. Parkin-Q311X mice exhibit multiple late-onset and progressive hypokinetic motor deficits. Stereological analyses reveal that the mutant mice develop age-dependent DA neuron degeneration in substantia nigra accompanied by a significant loss of DA neuron terminals in the striatum. Neurochemical analyses reveal a significant reduction of the striatal dopamine level in mutant mice, which is significantly correlated with their hypokinetic motor deficits. Finally, mutant Parkin-Q311X mice, but not wild-type controls, exhibit age-dependent accumulation of proteinase-K resistant endogenous α-synuclein in substantia nigra and co-localized with 3-nitrotyrosine, a marker for oxidative protein damage. Hence, our study provides the first mammalian genetic evidence that dominant toxicity of a parkin mutant is sufficient to elicit age-dependent hypokinetic motor deficits and DA neuron loss in vivo, and uncovers a causal relationship between dominant parkin toxicity and progressive α-synuclein accumulation in DA neurons. Our study underscores the need to further explore the putative link between parkin dominant toxicity and PD. PMID:19228951

  4. Mice Deficient in Proglucagon-Derived Peptides Exhibit Glucose Intolerance on a High-Fat Diet but Are Resistant to Obesity.

    PubMed

    Takagi, Yusuke; Kinoshita, Keita; Ozaki, Nobuaki; Seino, Yusuke; Murata, Yoshiharu; Oshida, Yoshiharu; Hayashi, Yoshitaka

    2015-01-01

    Homozygous glucagon-GFP knock-in mice (Gcggfp/gfp) lack proglucagon derived-peptides including glucagon and GLP-1, and are normoglycemic. We have previously shown that Gcggfp/gfp show improved glucose tolerance with enhanced insulin secretion. Here, we studied glucose and energy metabolism in Gcggfp/gfp mice fed a high-fat diet (HFD). Male Gcggfp/gfp and Gcggfp/+ mice were fed either a normal chow diet (NCD) or an HFD for 15-20 weeks. Regardless of the genotype, mice on an HFD showed glucose intolerance, and Gcggfp/gfp mice on HFD exhibited impaired insulin secretion whereas Gcggfp/+ mice on HFD exhibited increased insulin secretion. A compensatory increase in β-cell mass was observed in Gcggfp/+mice on HFD, but not in Gcggfp/gfp mice on the same diet. Weight gain was significantly lower in Gcggfp/gfp mice than in Gcggfp/+mice. Oxygen consumption was enhanced in Gcggfp/gfp mice compared to Gcggfp/+ mice on an HFD. HFD feeding significantly increased uncoupling protein 1 mRNA expression in brown adipose and inguinal white adipose tissues of Gcggfp/gfp mice, but not of Gcggfp/+mice. Treatment with the glucagon-like peptide-1 receptor agonist liraglutide (200 mg/kg) improved glucose tolerance in Gcggfp/gfp mice and insulin content in Gcggfp/gfp and Gcggfp/+ mice was similar after liraglutide treatment. Our findings demonstrate that Gcggfp/gfp mice develop diabetes upon HFD-feeding in the absence of proglucagon-derived peptides, although they are resistant to diet-induced obesity.

  5. High-Level Waste Melter Study Report

    SciTech Connect

    Perez Jr, Joseph M; Bickford, Dennis F; Day, Delbert E; Kim, Dong-Sang; Lambert, Steven L; Marra, Sharon L; Peeler, David K; Strachan, Denis M; Triplett, Mark B; Vienna, John D; Wittman, Richard S

    2001-07-13

    At the Hanford Site in Richland, Washington, the path to site cleanup involves vitrification of the majority of the wastes that currently reside in large underground tanks. A Joule-heated glass melter is the equipment of choice for vitrifying the high-level fraction of these wastes. Even though this technology has general national and international acceptance, opportunities may exist to improve or change the technology to reduce the enormous cost of accomplishing the mission of site cleanup. Consequently, the U.S. Department of Energy requested the staff of the Tanks Focus Area to review immobilization technologies, waste forms, and modifications to requirements for solidification of the high-level waste fraction at Hanford to determine what aspects could affect cost reductions with reasonable long-term risk. The results of this study are summarized in this report.

  6. A hybrid cationic peptide composed of human β-defensin-1 and humanized θ-defensin sequences exhibits salt-resistant antimicrobial activity.

    PubMed

    Olli, Sudar; Nagaraj, Ramakrishnan; Motukupally, Swapna R

    2015-01-01

    We have designed a hybrid peptide by combining sequences of human β-defensin-1 (HBD-1) and θ-defensin, in an attempt to generate a molecule that combines the diversity in structure and biological activity of two different peptides to yield a promising therapeutic candidate. HBD-1 was chosen as it is a natural defensin of humans that is constitutively expressed, but its antibacterial activity is considerably impaired by elevated ionic strength. θ-Defensins are expressed in human bone marrow as a pseudogene and are homologous to rhesus monkey circular minidefensins. Retrocyclins are synthetic human θ-defensins. The cyclic nature of the θ-defensin peptides makes them salt resistant, nonhemolytic, and virtually noncytotoxic in vitro. However, a nonhuman circular molecule developed for clinical use would be less viable than a linear molecule. In this study, we have fused the C-terminal region of HBD-1 to the nonapeptide sequence of a synthetic retrocyclin. Cyclization was achieved by joining the terminal ends of the hybrid peptide by a disulfide bridge. The hybrid peptide with or without the disulfide bridge exhibited enhanced antimicrobial activity against both Gram-negative and Gram-positive bacteria as well as against fungi, including clinical bacterial isolates from eye infections. The peptide retained activity in the presence of NaCl and serum and was nonhemolytic in vitro. Thus, the hybrid peptide generated holds potential as a new class of antibiotics.

  7. EAP high-level product architecture

    NASA Astrophysics Data System (ADS)

    Gudlaugsson, T. V.; Mortensen, N. H.; Sarban, R.

    2013-04-01

    EAP technology has the potential to be used in a wide range of applications. This poses the challenge to the EAP component manufacturers to develop components for a wide variety of products. Danfoss Polypower A/S is developing an EAP technology platform, which can form the basis for a variety of EAP technology products while keeping complexity under control. High level product architecture has been developed for the mechanical part of EAP transducers, as the foundation for platform development. A generic description of an EAP transducer forms the core of the high level product architecture. This description breaks down the EAP transducer into organs that perform the functions that may be present in an EAP transducer. A physical instance of an EAP transducer contains a combination of the organs needed to fulfill the task of actuator, sensor, and generation. Alternative principles for each organ allow the function of the EAP transducers to be changed, by basing the EAP transducers on a different combination of organ alternatives. A model providing an overview of the high level product architecture has been developed to support daily development and cooperation across development teams. The platform approach has resulted in the first version of an EAP technology platform, on which multiple EAP products can be based. The contents of the platform have been the result of multi-disciplinary development work at Danfoss PolyPower, as well as collaboration with potential customers and research institutions. Initial results from applying the platform on demonstrator design for potential applications are promising. The scope of the article does not include technical details.

  8. Materials Science of High-Level Nuclear Waste Immobilization

    SciTech Connect

    Weber, William J.; Navrotsky, Alexandra; Stefanovsky, S. V.; Vance, E. R.; Vernaz, Etienne Y.

    2009-01-09

    With the increasing demand for the development of more nuclear power comes the responsibility to address the technical challenges of immobilizing high-level nuclear wastes in stable solid forms for interim storage or disposition in geologic repositories. The immobilization of high-level nuclear wastes has been an active area of research and development for over 50 years. Borosilicate glasses and complex ceramic composites have been developed to meet many technical challenges and current needs, although regulatory issues, which vary widely from country to country, have yet to be resolved. Cooperative international programs to develop advanced proliferation-resistant nuclear technologies to close the nuclear fuel cycle and increase the efficiency of nuclear energy production might create new separation waste streams that could demand new concepts and materials for nuclear waste immobilization. This article reviews the current state-of-the-art understanding regarding the materials science of glasses and ceramics for the immobilization of high-level nuclear waste and excess nuclear materials and discusses approaches to address new waste streams.

  9. Python based high-level synthesis compiler

    NASA Astrophysics Data System (ADS)

    Cieszewski, Radosław; Pozniak, Krzysztof; Romaniuk, Ryszard

    2014-11-01

    This paper presents a python based High-Level synthesis (HLS) compiler. The compiler interprets an algorithmic description of a desired behavior written in Python and map it to VHDL. FPGA combines many benefits of both software and ASIC implementations. Like software, the mapped circuit is flexible, and can be reconfigured over the lifetime of the system. FPGAs therefore have the potential to achieve far greater performance than software as a result of bypassing the fetch-decode-execute operations of traditional processors, and possibly exploiting a greater level of parallelism. Creating parallel programs implemented in FPGAs is not trivial. This article describes design, implementation and first results of created Python based compiler.

  10. Service Oriented Architecture for High Level Applications

    SciTech Connect

    Chu, Chungming; Chevtsov, Sergei; Wu, Juhao; Shen, Guobao; /Brookhaven

    2012-06-28

    Standalone high level applications often suffer from poor performance and reliability due to lengthy initialization, heavy computation and rapid graphical update. Service-oriented architecture (SOA) is trying to separate the initialization and computation from applications and to distribute such work to various service providers. Heavy computation such as beam tracking will be done periodically on a dedicated server and data will be available to client applications at all time. Industrial standard service architecture can help to improve the performance, reliability and maintainability of the service. Robustness will also be improved by reducing the complexity of individual client applications.

  11. Chlamydia trachomatis clinical isolates identified as tetracycline resistant do not exhibit resistance in vitro: whole-genome sequencing reveals a mutation in porB but no evidence for tetracycline resistance genes.

    PubMed

    O'Neill, C E; Seth-Smith, H M B; Van Der Pol, B; Harris, S R; Thomson, N R; Cutcliffe, L T; Clarke, I N

    2013-04-01

    Chlamydia trachomatis is the most common bacterial sexually transmitted infection worldwide and the leading cause of preventable blindness in developing countries. Tetracycline is commonly the drug of choice for treating C. trachomatis infections, but cases of antibiotic resistance in clinical isolates have previously been reported. Here, we used antibiotic resistance assays and whole-genome sequencing to interrogate the hypothesis that two clinical isolates (IU824 and IU888) have acquired mechanisms of antibiotic resistance. Immunofluorescence staining was used to identify C. trachomatis inclusions in cell cultures grown in the presence of tetracycline; however, only antibiotic-free control cultures yielded the strong fluorescence associated with the presence of chlamydial inclusions. Infectivity was lost upon passage of harvested cultures grown in the presence of tetracycline into antibiotic-free medium, so we conclude that these isolates were phenotypically sensitive to tetracycline. Comparisons of the genome and plasmid sequences for the two isolates with tetracycline-sensitive strains did not identify regions of low sequence identity that could accommodate horizontally acquired resistance genes, and the tetracycline binding region of the 16S rRNA gene was identical to that of the sensitive control strains. The porB gene of strain IU824, however, was found to contain a premature stop codon not previously identified, which is noteworthy but unlikely to be related to tetracycline resistance. In conclusion, we found no evidence of tetracycline resistance in the two strains investigated, and it seems most likely that the small, aberrant inclusions previously identified resulted from the high chlamydial load used in the original antibiotic resistance assays.

  12. Commissioning of the CMS High Level Trigger

    SciTech Connect

    Agostino, Lorenzo; et al.

    2009-08-01

    The CMS experiment will collect data from the proton-proton collisions delivered by the Large Hadron Collider (LHC) at a centre-of-mass energy up to 14 TeV. The CMS trigger system is designed to cope with unprecedented luminosities and LHC bunch-crossing rates up to 40 MHz. The unique CMS trigger architecture only employs two trigger levels. The Level-1 trigger is implemented using custom electronics, while the High Level Trigger (HLT) is based on software algorithms running on a large cluster of commercial processors, the Event Filter Farm. We present the major functionalities of the CMS High Level Trigger system as of the starting of LHC beams operations in September 2008. The validation of the HLT system in the online environment with Monte Carlo simulated data and its commissioning during cosmic rays data taking campaigns are discussed in detail. We conclude with the description of the HLT operations with the first circulating LHC beams before the incident occurred the 19th September 2008.

  13. High Level Waste Disposal System Optimization

    SciTech Connect

    Dirk Gombert; M. Connolly; J. Roach; W. Holtzscheiter

    2005-02-01

    The high level waste (HLW) disposal system consists of the Yucca Mountain Facility (YMF) and waste product (e.g. glass) generation facilities. Responsibility for management is shared between the U. S. Department of Energy (DOE) Offices of Civilian Radioactive Waste Management (DOE-RW) and Environmental Management (DOE-EM). The DOE-RW license application and the Waste Acceptance System Requirements Document (WASRD), as well as the DOE-EM Waste Acceptance Product Specification for Vitrified High Level Waste Forms (WAPS) govern the overall performance of the system. This basis for HLW disposal should be reassessed to consider waste form and process technology research and development (R&D), which have been conducted by DOE-EM, international agencies (i.e. ANSTO, CEA), and the private sector; as well as the technical bases for including additional waste forms in the final license application. This will yield a more optimized HLW disposal system to accelerate HLW disposition, more efficient utilization of the YMF, and overall system cost reduction.

  14. Hot-wall corrosion testing of simulated high level nuclear waste

    SciTech Connect

    Chandler, G.T.; Zapp, P.E.; Mickalonis, J.I.

    1995-01-01

    Three materials of construction for steam tubes used in the evaporation of high level radioactive waste were tested under heat flux conditions, referred to as hot-wall tests. The materials were type 304L stainless steel alloy C276, and alloy G3. Non-radioactive acidic and alkaline salt solutions containing halides and mercury simulated different high level waste solutions stored or processed at the United States Department of Energy`s Savannah River Site. Alloy C276 was also tested for corrosion susceptibility under steady-state conditions. The nickel-based alloys C276 and G3 exhibited excellent corrosion resistance under the conditions studied. Alloy C276 was not susceptible to localized corrosion and had a corrosion rate of 0.01 mpy (0.25 {mu}m/y) when exposed to acidic waste sludge and precipitate slurry at a hot-wall temperature of 150{degrees}C. Type 304L was susceptible to localized corrosion under the same conditions. Alloy G3 had a corrosion rate of 0.1 mpy (2.5 {mu}m/y) when exposed to caustic high level waste evaporator solution at a hot-wall temperature of 220{degrees}C compared to 1.1 mpy (28.0 {mu}/y) for type 304L. Under extreme caustic conditions (45 weight percent sodium hydroxide) G3 had a corrosion rate of 0.1 mpy (2.5 {mu}m/y) at a hot-wall temperature of 180{degrees}C while type 304L had a high corrosion rate of 69.4 mpy (1.8 mm/y).

  15. Umbra's High Level Architecture (HLA) Interface

    SciTech Connect

    GOTTLIEB, ERIC JOSEPH; MCDONALD, MICHAEL J.; OPPEL III, FRED J.

    2002-04-01

    This report describes Umbra's High Level Architecture HLA library. This library serves as an interface to the Defense Simulation and Modeling Office's (DMSO) Run Time Infrastructure Next Generation Version 1.3 (RTI NG1.3) software library and enables Umbra-based models to be federated into HLA environments. The Umbra library was built to enable the modeling of robots for military and security system concept evaluation. A first application provides component technologies that ideally fit the US Army JPSD's Joint Virtual Battlespace (JVB) simulation framework for Objective Force concept analysis. In addition to describing the Umbra HLA library, the report describes general issues of integrating Umbra with RTI code and outlines ways of building models to support particular HLA simulation frameworks like the JVB.

  16. The High Level Data Reduction Library

    NASA Astrophysics Data System (ADS)

    Ballester, P.; Gabasch, A.; Jung, Y.; Modigliani, A.; Taylor, J.; Coccato, L.; Freudling, W.; Neeser, M.; Marchetti, E.

    2015-09-01

    The European Southern Observatory (ESO) provides pipelines to reduce data for most of the instruments at its Very Large telescope (VLT). These pipelines are written as part of the development of VLT instruments, and are used both in the ESO's operational environment and by science users who receive VLT data. All the pipelines are highly specific geared toward instruments. However, experience showed that the independently developed pipelines include significant overlap, duplication and slight variations of similar algorithms. In order to reduce the cost of development, verification and maintenance of ESO pipelines, and at the same time improve the scientific quality of pipelines data products, ESO decided to develop a limited set of versatile high-level scientific functions that are to be used in all future pipelines. The routines are provided by the High-level Data Reduction Library (HDRL). To reach this goal, we first compare several candidate algorithms and verify them during a prototype phase using data sets from several instruments. Once the best algorithm and error model have been chosen, we start a design and implementation phase. The coding of HDRL is done in plain C and using the Common Pipeline Library (CPL) functionality. HDRL adopts consistent function naming conventions and a well defined API to minimise future maintenance costs, implements error propagation, uses pixel quality information, employs OpenMP to take advantage of multi-core processors, and is verified with extensive unit and regression tests. This poster describes the status of the project and the lesson learned during the development of reusable code implementing algorithms of high scientific quality.

  17. New Rice for Africa (NERICA) cultivars exhibit different levels of post-attachment resistance against the parasitic weeds Striga hermonthica and Striga asiatica.

    PubMed

    Cissoko, Mamadou; Boisnard, Arnaud; Rodenburg, Jonne; Press, Malcolm C; Scholes, Julie D

    2011-12-01

    Striga hermonthica and S. asiatica are root parasitic weeds that infect the major cereal crops of sub-Saharan Africa causing severe losses in yield. The interspecific upland NEw RICe for Africa (NERICA) cultivars are popular amongst subsistence farmers, but little is known about their post-attachment resistance against Striga. Here, we evaluate the post-attachment resistance levels of the NERICA cultivars and their parents against ecotypes of S. hermonthica and S.asiatica, characterize the phenotype of the resistance mechanisms and determine the effect of Striga on host biomass. Some NERICA cultivars showed good broad-spectrum resistance against several Striga ecotypes, whereas others showed intermediate resistance or were very susceptible. The phenotype of a resistant interaction was often characterized by an inability of the parasite to penetrate the endodermis. Moreover, some parasites formed only a few connections to the host xylem, grew slowly and remained small. The most resistant NERICA cultivars were least damaged by Striga, although even a small number of parasites caused a reduction in above-ground host biomass. The elucidation of the molecular genetic basis of the resistance mechanisms and tolerance would allow the development of cultivars with multiple, durable resistance for use in farmers' fields.

  18. Proton Affinity Calculations with High Level Methods.

    PubMed

    Kolboe, Stein

    2014-08-12

    Proton affinities, stretching from small reference compounds, up to the methylbenzenes and naphthalene and anthracene, have been calculated with high accuracy computational methods, viz. W1BD, G4, G3B3, CBS-QB3, and M06-2X. Computed and the currently accepted reference proton affinities are generally in excellent accord, but there are deviations. The literature value for propene appears to be 6-7 kJ/mol too high. Reported proton affinities for the methylbenzenes seem 4-5 kJ/mol too high. G4 and G3 computations generally give results in good accord with the high level W1BD. Proton affinity values computed with the CBS-QB3 scheme are too low, and the error increases with increasing molecule size, reaching nearly 10 kJ/mol for the xylenes. The functional M06-2X fails markedly for some of the small reference compounds, in particular, for CO and ketene, but calculates methylbenzene proton affinities with high accuracy.

  19. HIGH LEVEL RF FOR THE SNS RING.

    SciTech Connect

    ZALTSMAN,A.; BLASKIEWICZ,M.; BRENNAN,J.; BRODOWSKI,J.; METH,M.; SPITZ,R.; SEVERINO,F.

    2002-06-03

    A high level RF system (HLRF) consisting of power amplifiers (PA's) and ferrite loaded cavities is being designed and built by Brookhaven National Laboratory (BNL) for the Spallation Neutron Source (SNS) project. It is a fixed frequency, two harmonic system whose main function is to maintain a gap for the kicker rise time. Three cavities running at the fundamental harmonic (h=l) will provide 40 kV and one cavity at the second harmonic (h=2) will provide 20 kV. Each cavity has two gaps with a design voltage of 10 kV per gap and will be driven by a power amplifier (PA) directly adjacent to it. The PA uses a 600kW tetrode to provide the necessary drive current. The anode of the tetrode is magnetically coupled to the downstream cell of the cavity. Drive to the PA will be provided by a wide band, solid state amplifier located remotely. A dynamic tuning scheme will be implemented to help compensate for the effect of beam loading.

  20. Decontamination of high-level waste canisters

    SciTech Connect

    Nesbitt, J.F.; Slate, S.C.; Fetrow, L.K.

    1980-12-01

    This report presents evaluations of several methods for the in-process decontamination of metallic canisters containing any one of a number of solidified high-level waste (HLW) forms. The use of steam-water, steam, abrasive blasting, electropolishing, liquid honing, vibratory finishing and soaking have been tested or evaluated as potential techniques to decontaminate the outer surfaces of HLW canisters. Either these techniques have been tested or available literature has been examined to assess their applicability to the decontamination of HLW canisters. Electropolishing has been found to be the most thorough method to remove radionuclides and other foreign material that may be deposited on or in the outer surface of a canister during any of the HLW processes. Steam or steam-water spraying techniques may be adequate for some applications but fail to remove all contaminated forms that could be present in some of the HLW processes. Liquid honing and abrasive blasting remove contamination and foreign material very quickly and effectively from small areas and components although these blasting techniques tend to disperse the material removed from the cleaned surfaces. Vibratory finishing is very capable of removing the bulk of contamination and foreign matter from a variety of materials. However, special vibratory finishing equipment would have to be designed and adapted for a remote process. Soaking techniques take long periods of time and may not remove all of the smearable contamination. If soaking involves pickling baths that use corrosive agents, these agents may cause erosion of grain boundaries that results in rough surfaces.

  1. Performance of the CMS High Level Trigger

    NASA Astrophysics Data System (ADS)

    Perrotta, Andrea

    2015-12-01

    The CMS experiment has been designed with a 2-level trigger system. The first level is implemented using custom-designed electronics. The second level is the so-called High Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. For Run II of the Large Hadron Collider, the increases in center-of-mass energy and luminosity will raise the event rate to a level challenging for the HLT algorithms. The increase in the number of interactions per bunch crossing, on average 25 in 2012, and expected to be around 40 in Run II, will be an additional complication. We present here the expected performance of the main triggers that will be used during the 2015 data taking campaign, paying particular attention to the new approaches that have been developed to cope with the challenges of the new run. This includes improvements in HLT electron and photon reconstruction as well as better performing muon triggers. We will also present the performance of the improved tracking and vertexing algorithms, discussing their impact on the b-tagging performance as well as on the jet and missing energy reconstruction.

  2. Defense High Level Waste Disposal Container System Description Document

    SciTech Connect

    N. E. Pettit

    2001-07-13

    The Defense High Level Waste Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers are loaded and sealed in the surface waste handling facilities, transferred to the underground through the accesses using a rail mounted transporter, and emplaced in emplacement drifts. The defense high level waste (HLW) disposal container provides long-term confinement of the commercial HLW and defense HLW (including immobilized plutonium waste forms [IPWF]) placed within disposable canisters, and withstands the loading, transfer, emplacement, and retrieval loads and environments. US Department of Energy (DOE)-owned spent nuclear fuel (SNF) in disposable canisters may also be placed in a defense HLW disposal container along with commercial HLW waste forms, which is known as co-disposal. The Defense High Level Waste Disposal Container System provides containment of waste for a designated period of time, and limits radionuclide release. The disposal container/waste package maintains the waste in a designated configuration, withstands maximum handling and rockfall loads, limits the individual canister temperatures after emplacement, resists corrosion in the expected handling and repository environments, and provides containment of waste in the event of an accident. Defense HLW disposal containers for HLW disposal will hold up to five HLW canisters. Defense HLW disposal containers for co-disposal will hold up to five HLW canisters arranged in a ring and one DOE SNF canister inserted in the center and/or one or more DOE SNF canisters displacing a HLW canister in the ring. Defense HLW disposal containers also will hold two Multi-Canister Overpacks (MCOs) and two HLW canisters in one disposal container. The disposal container will include outer and inner cylinders, outer and inner cylinder lids, and may include a canister guide. An exterior label will provide a means by

  3. DEFENSE HIGH LEVEL WASTE GLASS DEGRADATION

    SciTech Connect

    W. Ebert

    2001-09-20

    The purpose of this Analysis/Model Report (AMR) is to document the analyses that were done to develop models for radionuclide release from high-level waste (HLW) glass dissolution that can be integrated into performance assessment (PA) calculations conducted to support site recommendation and license application for the Yucca Mountain site. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M&O 2000a). It specifically addresses the item, ''Defense High Level Waste Glass Degradation'', of the product technical work plan. The AP-3.15Q Attachment 1 screening criteria determines the importance for its intended use of the HLW glass model derived herein to be in the category ''Other Factors for the Postclosure Safety Case-Waste Form Performance'', and thus indicates that this factor does not contribute significantly to the postclosure safety strategy. Because the release of radionuclides from the glass will depend on the prior dissolution of the glass, the dissolution rate of the glass imposes an upper bound on the radionuclide release rate. The approach taken to provide a bound for the radionuclide release is to develop models that can be used to calculate the dissolution rate of waste glass when contacted by water in the disposal site. The release rate of a particular radionuclide can then be calculated by multiplying the glass dissolution rate by the mass fraction of that radionuclide in the glass and by the surface area of glass contacted by water. The scope includes consideration of the three modes by which water may contact waste glass in the disposal system: contact by humid air, dripping water, and immersion. The models for glass dissolution under these contact modes are all based on the rate expression for aqueous dissolution of borosilicate glasses. The mechanism and rate expression for aqueous dissolution are adequately understood; the analyses in this AMR were conducted to

  4. Tomato cystine-knot miniproteins possessing anti-angiogenic activity exhibit in vitro gastrointestinal stability, intestinal absorption and resistance to food industrial processing.

    PubMed

    Treggiari, Davide; Zoccatelli, Gianni; Chignola, Roberto; Molesini, Barbara; Minuz, Pietro; Pandolfini, Tiziana

    2017-04-15

    The cystine-knot miniproteins present in tomato fruit (TCMPs) have been shown to exert anti-angiogenic effects by inhibiting endothelial cell migration and to display resistance to gastrointestinal proteolytic attack. To better define the pharmacological potential of TCMPs, their oral bioavailability and their resistance to industrial processing must be assessed. To explore the intestinal transport of TCMPs we used the differentiated Caco-2 cells model. After 24h incubation, 37.73±9.34% of TCMPs crossed the epithelium, without altering the integrity of the cell layer. To assess the effects of the industrial processing on the biochemical features and the biological activity of TCMPs, we developed a method for purifying the proteins from tomato paste. The tomato-paste purified TCMPs retained the resistance to gastrointestinal digestion and the inhibitory activity towards endothelial cell migration. Our previous and present results collectively demonstrate that TCMPs possess interesting features for drug development.

  5. Transgenic soybean overexpressing GmSamT1 exhibits resistance to multiple-HG types of soybean cysts nematode heterodera glycines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean (Glycine max (L.) Merr.) salicylic acid methyl transferase (GmSAMT1) catalyzes the conversion of salicylic acid to methyl salicylate. Prior results showed that when GmSAMT1 was overexpressed in transgenic soybean hairy roots, resistance is conferred against soybean cyst nematode (SCN), Heter...

  6. Influenza A(H1N1)pdm09 virus exhibiting enhanced cross-resistance to oseltamivir and peramivir due to a dual H275Y/G147R substitution, Japan, March 2016.

    PubMed

    Takashita, Emi; Fujisaki, Seiichiro; Shirakura, Masayuki; Nakamura, Kazuya; Kishida, Noriko; Kuwahara, Tomoko; Shimazu, Yukie; Shimomura, Takeshi; Watanabe, Shinji; Odagiri, Takato

    2016-06-16

    An influenza A(H1N1)pdm09 virus carrying a G147R substitution in combination with an H275Y substitution in the neuraminidase protein, which confers cross-resistance to oseltamivir and peramivir, was detected from an immunocompromised inpatient in Japan, March 2016. This dual H275Y/G147R mutant virus exhibited enhanced cross-resistance to both drugs compared with the single H275Y mutant virus and reduced susceptibility to zanamivir, although it showed normal inhibition by laninamivir.

  7. Transgenic soybean overexpressing GmSAMT1 exhibits resistance to multiple-HG types of soybean cyst nematode Heterodera glycines

    SciTech Connect

    Lin, Jingyu; Mazarei, Mitra; Zhao, Nan; Hatcher, Catherine N.; Wuddineh, Wegi A.; Rudis, Mary; Tschaplinski, Timothy J.; Pantalone, Vincent R.; Arelli, Prakash R.; Hewezi, Tarek; Chen, Feng; Stewart, Jr., Charles Neal

    2016-05-23

    Soybean (Glycine max (L.) Merr.) salicylic acid methyl transferase (GmSAMT1) catalyses the conversion of salicylic acid to methyl salicylate. Prior results showed that when GmSAMT1 was overexpressed in transgenic soybean hairy roots, resistance is conferred against soybean cyst nematode (SCN), Heterodera glycines Ichinohe. In this study, we produced transgenic soybean overexpressing GmSAMT1 and characterized their response to various SCN races. Transgenic plants conferred a significant reduction in the development of SCN HG type 1.2.5.7 (race 2), HG type 0 (race 3) and HG type 2.5.7 (race 5). Among transgenic lines, GmSAMT1 expression in roots was positively associated with SCN resistance. In some transgenic lines, there was a significant decrease in salicylic acid titer relative to control plants. No significant seed yield differences were observed between transgenics and control soybean plants grown in one greenhouse with 22 °C day/night temperature, whereas transgenic soybean had higher yield than controls grown a warmer greenhouse (27 °C day/23 °C night) temperature. In a 1-year field experiment in Knoxville, TN, there was no significant difference in seed yield between the transgenic and nontransgenic soybean under conditions with negligible SCN infection. We hypothesize that GmSAMT1 expression affects salicylic acid biosynthesis, which, in turn, attenuates SCN development, without negative consequences to soybean yield or other morphological traits. Furthermore, we conclude that GmSAMT1 overexpression confers broad resistance to multiple SCN races, which would be potentially applicable to commercial production.

  8. Penetration barrier contributes to bacterial biofilm-associated resistance against only select antibiotics, and exhibits genus-, strain- and antibiotic-specific differences.

    PubMed

    Singh, Rachna; Sahore, Simmi; Kaur, Preetinder; Rani, Alka; Ray, Pallab

    2016-08-01

    Bacterial biofilms are implicated in a wide range of implant-based and chronic infections. These infections are often associated with adverse therapeutic outcomes, owing to the decreased antibiotic susceptibility of biofilms compared with their planktonic counterparts. This altered biofilm susceptibility has been attributed to multiple factors, including a reduced antibiotic penetration. Although several studies have addressed the role of penetration barrier in biofilm-associated drug resistance, it remains inconclusive. This study was done to elucidate antibiotic penetration through biofilms formed by Staphylococcus aureus, S. epidermidis, Escherichia coli and Klebsiella pneumoniae, using an agar disk diffusion assay. Penetration capacity of six antimicrobial drugs from different classes (β-lactams, aminoglycosides, tetracyclines, phenicols, fluoroquinolones and glycopeptides) through biofilms formed by standard strains and clinical isolates from catheter-related bloodstream infections (CRBSI) was elucidated by measuring their growth-inhibition zones in lawn cultures on Mueller-Hinton agar, following diffusion of an antibiotic from an overlying disk through their biofilm to the agar medium. Penetration of only select antimicrobials (vancomycin and chloramphenicol) was hindered through biofilms. There was considerable variation in biofilm-permeating capacity depending upon the genus, strain/CRBSI isolate and antibiotic tested. Furthermore, antibiotics failed to kill the biofilm cells independent of penetration, indicating that other factors contributed substantially to biofilm resistance.

  9. Characterization of Klebsiella sp. strain 10982, a colonizer of humans that contains novel antibiotic resistance alleles and exhibits genetic similarities to plant and clinical Klebsiella isolates.

    PubMed

    Hazen, Tracy H; Zhao, LiCheng; Sahl, Jason W; Robinson, Gwen; Harris, Anthony D; Rasko, David A; Johnson, J Kristie

    2014-01-01

    A unique Klebsiella species strain, 10982, was cultured from a perianal swab specimen obtained from a patient in the University of Maryland Medical Center intensive care unit. Klebsiella sp. 10982 possesses a large IncA/C multidrug resistance plasmid encoding a novel FOX AmpC β-lactamase designated FOX-10. A novel variant of the LEN β-lactamase was also identified. Genome sequencing and bioinformatic analysis demonstrated that this isolate contains genes associated with nitrogen fixation, allantoin metabolism, and citrate fermentation. These three gene regions are typically present in either Klebsiella pneumoniae clinical isolates or Klebsiella nitrogen-fixing endophytes but usually not in the same organism. Phylogenomic analysis of Klebsiella sp. 10982 and sequenced Klebsiella genomes demonstrated that Klebsiella sp. 10982 is present on a branch that is located intermediate between the genomes of nitrogen-fixing endophytes and K. pneumoniae clinical isolates. Metabolic features identified in the genome of Klebsiella sp. 10982 distinguish this isolate from other Klebsiella clinical isolates. These features include the nitrogen fixation (nif) gene cluster, which is typically present in endophytic Klebsiella isolates and is absent from Klebsiella clinical isolates. Additionally, the Klebsiella sp. 10982 genome contains genes associated with allantoin metabolism, which have been detected primarily in K. pneumoniae isolates from liver abscesses. Comparative genomic analysis of Klebsiella sp. 10982 demonstrated that this organism has acquired genes conferring new metabolic strategies and novel antibiotic resistance alleles, both of which may enhance its ability to colonize the human body.

  10. Transgenic Pearl Millet Male Fertility Restorer Line (ICMP451) and Hybrid (ICMH451) Expressing Brassica juncea Nonexpressor of Pathogenesis Related Genes 1 (BjNPR1) Exhibit Resistance to Downy Mildew Disease

    PubMed Central

    Khareedu, Venkateswara Rao; Vudem, Dashavantha Reddy

    2014-01-01

    Brassica juncea Nonexpressor of pathogenesis-related genes 1 (BjNPR1) has been introduced into pearl millet male fertility restorer line ICMP451 by Agrobacterium tumefaciens-mediated genetic transformation. Transgenic pearl millet plants were regenerated from the phosphinothricin-resistant calli obtained after co-cultivation with A. tumefaciens strain LBA4404 harbouring Ti plasmid pSB111-bar-BjNPR1. Molecular analyses confirmed the stable integration and expression of BjNPR1 in transgenic pearl millet lines. Transgenes BjNPR1 and bar were stably inherited and disclosed co-segregation in subsequent generations in a Mendelian fashion. Transgenic pearl millet hybrid ICMH451-BjNPR1 was developed by crossing male-sterile line 81A X homozygous transgenic line ICMP451-BjNPR1. T3 and T4 homozygous lines of ICMP451-BjNPR1 and hybrid ICMH451-BjNPR1 exhibited resistance to three strains of downy mildew pathogen, while the untransformed ICMP451 and the isogenic hybrid ICMH451 plants were found susceptible. Following infection with S. graminicola, differential expression of systemic acquired resistance pathway genes, UDP-glucose salicylic acid glucosyl transferase and pathogenesis related gene 1 was observed in transgenic ICMP451-BjNPR1 and untransformed plants indicating the activation of systemic acquired resistance pathway contributing to the transgene-mediated resistance against downy mildew. The transgenic pearl millet expressing BjNPR1 showed resistance to multiple strains of S. graminicola and, as such, seems promising for the development of durable downy mildew resistant hybrids. PMID:24603762

  11. Plastid-expressed 5-enolpyruvylshikimate-3-phosphate synthase genes provide high level glyphosate tolerance in tobacco.

    PubMed

    Ye, G N; Hajdukiewicz, P T; Broyles, D; Rodriguez, D; Xu, C W; Nehra, N; Staub, J M

    2001-02-01

    Plastid transformation (transplastomic) technology has several potential advantages for biotechnological applications including the use of unmodified prokaryotic genes for engineering, potential high-level gene expression and gene containment due to maternal inheritance in most crop plants. However, the efficacy of a plastid-encoded trait may change depending on plastid number and tissue type. We report a feasibility study in tobacco plastids to achieve high-level herbicide resistance in both vegetative tissues and reproductive organs. We chose to test glyphosate resistance via over-expression in plastids of tolerant forms of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Immunological, enzymatic and whole-plant assays were used to prove the efficacy of three different prokaryotic (Achromobacter, Agrobacterium and Bacillus) EPSPS genes. Using the Agrobacterium strain CP4 EPSPS as a model we identified translational control sequences that direct a 10,000-fold range of protein accumulation (to >10% total soluble protein in leaves). Plastid-expressed EPSPS could provide very high levels of glyphosate resistance, although levels of resistance in vegetative and reproductive tissues differed depending on EPSPS accumulation levels, and correlated to the plastid abundance in these tissues. Paradoxically, higher levels of plastid-expressed EPSPS protein accumulation were apparently required for efficacy than from a similar nuclear-encoded gene. Nevertheless, the demonstration of high-level glyphosate tolerance in vegetative and reproductive organs using transplastomic technology provides a necessary step for transfer of this technology to other crop species.

  12. High-level waste-form-product performance evaluation. [Leaching; waste loading; mechanical stability

    SciTech Connect

    Bernadzikowski, T A; Allender, J S; Stone, J A; Gordon, D E; Gould, Jr, T H; Westberry, III, C F

    1982-01-01

    Seven candidate waste forms were evaluated for immobilization and geologic disposal of high-level radioactive wastes. The waste forms were compared on the basis of leach resistance, mechanical stability, and waste loading. All forms performed well at leaching temperatures of 40, 90, and 150/sup 0/C. Ceramic forms ranked highest, followed by glasses, a metal matrix form, and concrete. 11 tables.

  13. Allium stipitatum Extract Exhibits In Vivo Antibacterial Activity against Methicillin-Resistant Staphylococcus aureus and Accelerates Burn Wound Healing in a Full-Thickness Murine Burn Model.

    PubMed

    Karunanidhi, Arunkumar; Ghaznavi-Rad, Ehsanollah; Jeevajothi Nathan, Jayakayatri; Abba, Yusuf; van Belkum, Alex; Neela, Vasanthakumari

    2017-01-01

    The in vivo antibacterial and burn wound healing potency of Persian shallot bulbs (Allium stipitatum) were explored in a mice burn model infected with methicillin-resistant Staphylococcus aureus (MRSA). Hexane (ASHE) and dichloromethane (ASDE) extracts were tested. Female BALB/c mice were inflicted with third-degree thermal injury followed by infection with MRSA. ASHE and ASDE formulated with simple ointment base (SOB) at concentrations of 1%, 2%, and 5% (w/w) were topically applied to burn wounds twice a day for 20 days. Silver sulfadiazine (1%) served as drug positive control. Microbiological analysis was carried out on 1, 2, 3, 4, and 5 days postwounding (dpw) and histopathological analysis at the end of the experiment (20 dpw). Both ointments demonstrated strong antibacterial activity with complete elimination of MRSA at 48-72 h after infection. The rate of wound contraction was higher (95-100%) in mice groups treated with ASHE and ASDE ointments after 15 dpw. Histological analysis revealed significant increase (p < 0.05) in epithelialization and collagenation in treated groups. The ASHE and ASDE were found to be relatively noncytotoxic and safe to Vero cell line (383.4 μg mL(-1); 390.6 μg mL(-1)), suggesting the extracts as safe topical antibacterial as well as promising alternatives in managing thermal injuries.

  14. Allium stipitatum Extract Exhibits In Vivo Antibacterial Activity against Methicillin-Resistant Staphylococcus aureus and Accelerates Burn Wound Healing in a Full-Thickness Murine Burn Model

    PubMed Central

    Karunanidhi, Arunkumar; Jeevajothi Nathan, Jayakayatri; van Belkum, Alex

    2017-01-01

    The in vivo antibacterial and burn wound healing potency of Persian shallot bulbs (Allium stipitatum) were explored in a mice burn model infected with methicillin-resistant Staphylococcus aureus (MRSA). Hexane (ASHE) and dichloromethane (ASDE) extracts were tested. Female BALB/c mice were inflicted with third-degree thermal injury followed by infection with MRSA. ASHE and ASDE formulated with simple ointment base (SOB) at concentrations of 1%, 2%, and 5% (w/w) were topically applied to burn wounds twice a day for 20 days. Silver sulfadiazine (1%) served as drug positive control. Microbiological analysis was carried out on 1, 2, 3, 4, and 5 days postwounding (dpw) and histopathological analysis at the end of the experiment (20 dpw). Both ointments demonstrated strong antibacterial activity with complete elimination of MRSA at 48–72 h after infection. The rate of wound contraction was higher (95–100%) in mice groups treated with ASHE and ASDE ointments after 15 dpw. Histological analysis revealed significant increase (p < 0.05) in epithelialization and collagenation in treated groups. The ASHE and ASDE were found to be relatively noncytotoxic and safe to Vero cell line (383.4 μg mL−1; 390.6 μg mL−1), suggesting the extracts as safe topical antibacterial as well as promising alternatives in managing thermal injuries. PMID:28321262

  15. Phenotypic- and Genotypic-Resistance Detection for Adaptive Resistance Management in Tetranychus urticae Koch

    PubMed Central

    Kwon, Deok Ho; Kang, Taek-Jun; Kim, Young Ho; Lee, Si Hyeock

    2015-01-01

    Rapid resistance detection is necessary for the adaptive management of acaricide-resistant populations of Tetranychus urticae. Detection of phenotypic and genotypic resistance was conducted by employing residual contact vial bioassay (RCV) and quantitative sequencing (QS) methods, respectively. RCV was useful for detecting the acaricide resistance levels of T. urticae, particularly for on-site resistance detection; however, it was only applicable for rapid-acting acaricides (12 out of 19 tested acaricides). QS was effective for determining the frequencies of resistance alleles on a population basis, which corresponded to 12 nonsynonymous point mutations associated with target-site resistance to five types of acaricides [organophosphates (monocrotophos, pirimiphos-methyl, dimethoate and chlorpyrifos), pyrethroids (fenpropathrin and bifenthrin), abamectin, bifenazate and etoxazole]. Most field-collected mites exhibited high levels of multiple resistance, as determined by RCV and QS data, suggesting the seriousness of their current acaricide resistance status in rose cultivation areas in Korea. The correlation analyses revealed moderate to high levels of positive relationships between the resistance allele frequencies and the actual resistance levels in only five of the acaricides evaluated, which limits the general application of allele frequency as a direct indicator for estimating actual resistance levels. Nevertheless, the resistance allele frequency data alone allowed for the evaluation of the genetic resistance potential and background of test mite populations. The combined use of RCV and QS provides basic information on resistance levels, which is essential for choosing appropriate acaricides for the management of resistant T. urticae. PMID:26545209

  16. Coping with naturally high levels of soil salinity and boron in the westside of central California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Westside of central California, over 200,000 ha exhibit naturally high levels of salinity and boron (B). The Coast Ranges of the west central California evolved from complex folding and faulting of sedimentary and igneous rocks of Mesozoic and Tertiary age. Cretaceous and Tertiary marine sedi...

  17. A peptide derived from phage display library exhibits anti-tumor activity by targeting GRP78 in gastric cancer multidrug resistance cells.

    PubMed

    Kang, Jianqin; Zhao, Guohong; Lin, Tao; Tang, Shanhong; Xu, Guanghui; Hu, Sijun; Bi, Qian; Guo, Changcun; Sun, Li; Han, Shuang; Xu, Qian; Nie, Yongzhan; Wang, Biaoluo; Liang, Shuhui; Ding, Jie; Wu, Kaichun

    2013-10-10

    Multidrug resistance (MDR) remains a significant challenge to the clinical treatment of gastric cancer (GC). In the present study, using a phage display approach combined with MTT assays, we screened a specific peptide GMBP1 (Gastric cancer MDR cell-specific binding peptide), ETAPLSTMLSPY, which could bind to the surface of GC MDR cells specifically and reverse their MDR phenotypes. Immunocytochemical staining showed that the potential receptor of GMBP1 was located at the membrane and cytoplasm of MDR cells. In vitro and in vivo drug sensitivity assays, FACS analysis and Western blotting confirmed that GMBP1 was able to re-sensitize MDR cells to chemical drugs. Western blotting and proteomic approaches were used to screen the receptor of GMBP1, and GRP78, a MDR-related protein, was identified as a receptor of GMBP1. This result was further supported by immunofluoresence microscopy and Western blot. Additionally, Western blotting demonstrated that pre-incubation of GMBP1 in MDR cells greatly diminished MDR1, Bcl-2 and GRP78 expression but increased the expression of Bax, whereas downregulation of GRP78, function as a receptor and directly target for GMBP1, only inhibited MDR1 expression. Our findings suggest that GMBP1 could re-sensitize GC MDR cells to a variety of chemotherapeutic agents and this role might be mediated partly through down-regulating GRP78 expression and then inhibiting MDR1 expression. These findings indicate that peptide GMBP1 likely recognizes a novel GRP78 receptor and mediates cellular activities associated with the MDR phenotype, which provides new insight into research on the management of MDR in gastric cancer cells.

  18. Defense High Level Waste Disposal Container System Description

    SciTech Connect

    2000-10-12

    The Defense High Level Waste Disposal Container System supports the confinement and isolation of waste within the Engineered Barrier System of the Monitored Geologic Repository (MGR). Disposal containers are loaded and sealed in the surface waste handling facilities, transferred to the underground through the accesses using a rail mounted transporter, and emplaced in emplacement drifts. The defense high level waste (HLW) disposal container provides long-term confinement of the commercial HLW and defense HLW (including immobilized plutonium waste forms (IPWF)) placed within disposable canisters, and withstands the loading, transfer, emplacement, and retrieval loads and environments. U.S. Department of Energy (DOE)-owned spent nuclear fuel (SNF) in disposable canisters may also be placed in a defense HLW disposal container along with commercial HLW waste forms, which is known as 'co-disposal'. The Defense High Level Waste Disposal Container System provides containment of waste for a designated period of time, and limits radionuclide release. The disposal container/waste package maintains the waste in a designated configuration, withstands maximum handling and rockfall loads, limits the individual canister temperatures after emplacement, resists corrosion in the expected handling and repository environments, and provides containment of waste in the event of an accident. Defense HLW disposal containers for HLW disposal will hold up to five HLW canisters. Defense HLW disposal containers for co-disposal will hold up to five HLW canisters arranged in a ring and one DOE SNF canister in the ring. Defense HLW disposal containers also will hold two Multi-Canister Overpacks (MCOs) and two HLW canisters in one disposal container. The disposal container will include outer and inner cylinders, outer and inner cylinder lids, and may include a canister guide. An exterior label will provide a means by which to identify the disposal container and its contents. Different materials

  19. Recessive resistance to Cucurbit yellow stunting disorder virus in melon TGR 1551

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cucurbit yellow stunting disorder virus (CYSDV) reduces melon (Cucumis melo L.) fruit quality and yield in many parts of the world. Host plant resistance of melon to CYSDV is a high priority for sustainable melon production in affected production areas. High-level resistance to CYSDV exhibited by TG...

  20. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  1. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  2. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  3. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  4. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false High-level radioactive waste. 227.30...-level radioactive waste. High-level radioactive waste means the aqueous waste resulting from the operation of the first cycle solvent extraction system, or equivalent, and the concentrated waste...

  5. 46 CFR 119.530 - Bilge high level alarms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Bilge high level alarms. 119.530 Section 119.530... Bilge and Ballast Systems § 119.530 Bilge high level alarms. (a) Each vessel must be provided with a visual and audible alarm at the operating station to indicate a high water level in each of the...

  6. 46 CFR 182.530 - Bilge high level alarms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Bilge high level alarms. 182.530 Section 182.530... TONS) MACHINERY INSTALLATION Bilge and Ballast Systems § 182.530 Bilge high level alarms. (a) On a... operating station to indicate a high water level in each of the following normally unmanned spaces: (1)...

  7. Evaluation of high-level clouds in cloud resolving model simulations with ARM and KWAJEX observations

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Muhlbauer, Andreas; Ackerman, Thomas

    2015-12-01

    In this study, we evaluate high-level clouds in a cloud resolving model during two convective cases, ARM9707 and KWAJEX. The simulated joint histograms of cloud occurrence and radar reflectivity compare well with cloud radar and satellite observations when using a two-moment microphysics scheme. However, simulations performed with a single moment microphysical scheme exhibit low biases of approximately 20 dB. During convective events, two-moment microphysical overestimate the amount of high-level cloud and one-moment microphysics precipitate too readily and underestimate the amount and height of high-level cloud. For ARM9707, persistent large positive biases in high-level cloud are found, which are not sensitive to changes in ice particle fall velocity and ice nuclei number concentration in the two-moment microphysics. These biases are caused by biases in large-scale forcing and maintained by the periodic lateral boundary conditions. The combined effects include significant biases in high-level cloud amount, radiation, and high sensitivity of cloud amount to nudging time scale in both convective cases. The high sensitivity of high-level cloud amount to the thermodynamic nudging time scale suggests that thermodynamic nudging can be a powerful "tuning" parameter for the simulated cloud and radiation but should be applied with caution. The role of the periodic lateral boundary conditions in reinforcing the biases in cloud and radiation suggests that reducing the uncertainty in the large-scale forcing in high levels is important for similar convective cases and has far reaching implications for simulating high-level clouds in super-parameterized global climate models such as the multiscale modeling framework.

  8. Deep borehole disposal of high-level radioactive waste.

    SciTech Connect

    Stein, Joshua S.; Freeze, Geoffrey A.; Brady, Patrick Vane; Swift, Peter N.; Rechard, Robert Paul; Arnold, Bill Walter; Kanney, Joseph F.; Bauer, Stephen J.

    2009-07-01

    Preliminary evaluation of deep borehole disposal of high-level radioactive waste and spent nuclear fuel indicates the potential for excellent long-term safety performance at costs competitive with mined repositories. Significant fluid flow through basement rock is prevented, in part, by low permeabilities, poorly connected transport pathways, and overburden self-sealing. Deep fluids also resist vertical movement because they are density stratified. Thermal hydrologic calculations estimate the thermal pulse from emplaced waste to be small (less than 20 C at 10 meters from the borehole, for less than a few hundred years), and to result in maximum total vertical fluid movement of {approx}100 m. Reducing conditions will sharply limit solubilities of most dose-critical radionuclides at depth, and high ionic strengths of deep fluids will prevent colloidal transport. For the bounding analysis of this report, waste is envisioned to be emplaced as fuel assemblies stacked inside drill casing that are lowered, and emplaced using off-the-shelf oilfield and geothermal drilling techniques, into the lower 1-2 km portion of a vertical borehole {approx}45 cm in diameter and 3-5 km deep, followed by borehole sealing. Deep borehole disposal of radioactive waste in the United States would require modifications to the Nuclear Waste Policy Act and to applicable regulatory standards for long-term performance set by the US Environmental Protection Agency (40 CFR part 191) and US Nuclear Regulatory Commission (10 CFR part 60). The performance analysis described here is based on the assumption that long-term standards for deep borehole disposal would be identical in the key regards to those prescribed for existing repositories (40 CFR part 197 and 10 CFR part 63).

  9. Perceptual learning of parametric face categories leads to the integration of high-level class-based information but not to high-level pop-out.

    PubMed

    Kietzmann, Tim C; König, Peter

    2010-11-24

    To date, the relative contribution of the different levels of the visual hierarchy during perceptual decisions remains unclear. Typical models of visual processing, with the reverse hierarchy theory (RHT) as a prominent example, strongly emphasize the role of higher levels and interpret lower levels as sequence of simple feature detectors. Here, we investigate this issue based on two analyses. Using a novel combination of perceptual learning based on two classes of parametric faces and a subsequent odd-one-out paradigm, we first test a vital prediction of RHT: high-level pop-out. With this experimental approach, we overcome the low-level confounds of previous studies while still introducing distinct high-level representations. Contrary to previous findings, our analyses show that there is no high-level pop-out, despite very early, near-perfect classification accuracy and extensive training of our subjects. Second, we explore the underlying form of category representation during subsequent stages of perceptual training. This is accomplished by including class-external and class-internal target-distractor combinations. Whereas the subjects' responses during the first sessions are best explained instance-based and dependent on low-level metric differences, later patterns exhibit the inclusion of high-level, class-based information that is independent of target-stimulus similarity. Finally, we show that the utilized level of information is highly task-dependent.

  10. An in vivo highly antitumor-active tetrazolato-bridged dinuclear platinum(II) complex largely circumvents in vitro cisplatin resistance: two linkage isomers yield the same product upon reaction with 9-ethylguanine but exhibit different cytotoxic profiles.

    PubMed

    Uemura, Masako; Suzuki, Toshihiro; Nishio, Kazuto; Chikuma, Masahiko; Komeda, Seiji

    2012-07-01

    Cytotoxicity assays of azolato-bridged dinuclear Pt(II) complexes, [{cis-Pt(NH(3))(2)}(2)(μ-OH)(μ-azolato)](2+), where the azolato was pyrazolato (1), 1,2,3-triazolato-N1,N2 (2), tetrazolato-N1,N2 (3), or tetrazolato-N2,N3 (4), were performed in cisplatin-sensitive and -resistant human non-small-cell lung cancer cell lines (PC-9 and PC-14). These complexes largely circumvented the cisplatin resistance in both cell lines, with resistance factors for 1-4 in the range of 0.5-0.8 and 0.9-2.0 for PC-9 and PC-14 cells, respectively. Complex 4 exhibited approximately 10 times the cytotoxicity of 3. When 3 and 4 were reacted with 2 molar equiv. of 9-ethylguanine (9EtG), they yielded an identical product, [{cis-Pt(NH(3))(2)(9EtG-N7)}(2)(μ-tetrazolato-N1,N3)](3+), that had N1,N3 platinum coordination through a Pt(II) migration process on the tetrazolate ring. The second-order rate kinetics of these isomers were almost the same as each other and faster than those of 1 and 2. The cytotoxicity of azolato-bridged complexes, except for 3, increases as their kinetic rates in the 9EtG reaction increase.

  11. In-Use Evaluation of Peracetic Acid for High-Level Disinfection of Endoscopes.

    PubMed

    Chenjiao, Wu; Hongyan, Zhang; Qing, Gu; Xiaoqi, Zhong; Liying, Gu; Ying, Fang

    2016-01-01

    Many high-level disinfectants have been used for disinfection of endoscopes such as 2% glutaraldehyde (GA), 0.55% ortho-phthalaldehyde (OPA), and peracetic acid (PAA). Both GA and OPA are widely used in disinfection of endoscopes and have been previously discussed, but there is little research on the practical use of PAA as an endoscope disinfectant. An experimental model of a flexible gastrointestinal endoscope being contaminated with 9 strains of microorganism was designed. After the cleaning and disinfecting procedure was completed, we evaluated the biocidal activity (850 ppm PAA, 2% GA, and 0.55% OPA) on our flexible gastrointestinal endoscope model. We also evaluated sterilization effectiveness of PAA on other bacteria, including some antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile). The residual bacterial colony count number of the PAA-disinfected endoscope was significantly lower than that of the GA- and OPA-disinfected endoscopes. The biocidal effect and efficiency of the endoscope disinfection by PAA appeared to be better than either the GA- or OPA-disinfected endoscope. PAA has demonstrated a good sterilization effect on other bacterial species; of particular note are common antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile. The results of this study demonstrate that PAA is a fast and effective high-level disinfectant for use in the reprocessing of flexible endoscopes.

  12. Reference commercial high-level waste glass and canister definition.

    SciTech Connect

    Slate, S.C.; Ross, W.A.; Partain, W.L.

    1981-09-01

    This report presents technical data and performance characteristics of a high-level waste glass and canister intended for use in the design of a complete waste encapsulation package suitable for disposal in a geologic repository. The borosilicate glass contained in the stainless steel canister represents the probable type of high-level waste product that will be produced in a commercial nuclear-fuel reprocessing plant. Development history is summarized for high-level liquid waste compositions, waste glass composition and characteristics, and canister design. The decay histories of the fission products and actinides (plus daughters) calculated by the ORIGEN-II code are presented.

  13. Chicken albumin exhibits natural resistance to glycation.

    PubMed

    Zuck, Jessica; Borges, Chad R; Braun, Eldon J; Sweazea, Karen L

    2017-01-01

    Glycation of proteins and subsequent production of advanced glycation end products (AGEs) is a major contributor to the pathophysiology of diabetes. The objective of the present study was to compare the glycation of avian and human serum albumin to elucidate the mechanisms by which protein glycation in birds is prevented in the presence of naturally high plasma glucose concentrations. Solutions of purified chicken and human serum albumin (CSA and HSA) were prepared with four different glucose concentrations (0, 5.56, 11.1, and 22.2mM) and incubated at three temperatures (37.0, 39.8, and 41.4°C) for seven days. The solutions were sampled on Days 0, 3, and 7 and analyzed by liquid chromatography-electrospray ionization-mass spectrometry for the presence of glycated albumin. Four-way repeated measures ANOVA (p=0.032) indicate that all independent variables (albumin type, glucose concentration, temperature and time) interacted to affect the degree of glycation. With increasing glucose concentration, the glycation of both HSA and CSA increased with time at all temperatures. In addition, HSA was glycated to a greater extent than CSA at the two higher glucose concentrations for all temperature conditions. Glycation was elevated with increasing temperatures for HSA but not CSA. The results suggest an inherent difference between human and chicken albumin that contributes to the observed differences in glycation. Further research is needed to characterize this inherent difference in an effort to elucidate mechanisms by which avian plasma protein is glycated to a lesser degree than that of mammals (humans).

  14. Ethics on Exhibit

    ERIC Educational Resources Information Center

    Vick, Randy M.

    2011-01-01

    This article discusses ethical questions raised by an exhibition of work by an artist with a history of mental illness and the exhibition's relevance to art therapy and “outsider art” discourse on the subject. Considerations for how such an exhibit could be handled had the circumstances included an art therapist and art therapy client are…

  15. Neptunium estimation in dissolver and high-level-waste solutions

    SciTech Connect

    Pathak, P.N.; Prabhu, D.R.; Kanekar, A.S.; Manchanda, V.K.

    2008-07-01

    This papers deals with the optimization of the experimental conditions for the estimation of {sup 237}Np in spent-fuel dissolver/high-level waste solutions using thenoyltrifluoroacetone as the extractant. (authors)

  16. Holism and High Level Wellness in the Treatment of Alcoholism.

    ERIC Educational Resources Information Center

    Bartha, Robert; Davis, Tom

    1982-01-01

    Discusses how a holistic and wellness philosophy is a viable alternative in the treatment of alcoholism. Describes five major dimensions of high-level wellness: nutritional awareness, physical fitness, stress management, environmental sensitivity, and self-responsibility. (RC)

  17. High-Level Waste System Process Interface Description

    SciTech Connect

    d'Entremont, P.D.

    1999-01-14

    The High-Level Waste System is a set of six different processes interconnected by pipelines. These processes function as one large treatment plant that receives, stores, and treats high-level wastes from various generators at SRS and converts them into forms suitable for final disposal. The three major forms are borosilicate glass, which will be eventually disposed of in a Federal Repository, Saltstone to be buried on site, and treated water effluent that is released to the environment.

  18. Changes in insecticide resistance of the rice striped stem borer (Lepidoptera: Crambidae).

    PubMed

    Su, Jianya; Zhang, Zhenzhen; Wu, Min; Gao, Congfen

    2014-02-01

    Application of insecticides is the most important method to control Chilo suppressalis (Walker) (Lepidoptera: Crambidae), and continuous use of individual insecticides has driven the rapid development of insecticide resistance in C. suppressalis during the past 30 yr. Monitoring insecticide resistance provides information essential for integrated pest management. Insecticide resistance of field populations to monosultap, triazophos, chlorpyrifos, and abamectin in China was examined in 2010 and 2011. The results indicated that the resistance levels of 14 field populations to four insecticides were significantly different. Four populations showed moderate resistance, and other populations possessed low-level resistance or were susceptible to monosultap. Nine populations displayed an extremely high or a high level of resistance to triazophos, whereas four populations were sensitive to this agent. Five populations exhibited a low level of resistance to abamectin, while the others remained sensitive. When compared with historical data, resistance to monosultap and triazophos decreased significantly, and the percentage of populations with high-level or extremely high-level resistance was obviously reduced. By contrast, the resistance to abamectin increased slightly. The increasing and decreasing resistance levels reported in this study highlight the different evolutionary patterns of insecticide resistance in C. suppressalis. An overreliance on one or two insecticides may promote rapid development of resistance. Slow development of resistance to abamectin, which was used mainly in mixtures with other insecticides, implies that the use of insecticide mixtures may be an effective method to delay the evolution of resistance to insecticides.

  19. High-Level Carbapenem Resistance in a Klebsiella pneumoniae Clinical Isolate Is Due to the Combination of blaACT-1 β-Lactamase Production, Porin OmpK35/36 Insertional Inactivation, and Down-Regulation of the Phosphate Transport Porin PhoE

    PubMed Central

    Kaczmarek, Frank M.; Dib-Hajj, Fadia; Shang, Wenchi; Gootz, Thomas D.

    2006-01-01

    Clinical isolates of Klebsiella pneumoniae resistant to carbapenems and essentially all other antibiotics (multidrug resistant) are being isolated from some hospitals in New York City with increasing frequency. A highly related pair of K. pneumoniae strains isolated on the same day from one patient in a hospital in New York City were studied for antibiotic resistance. One (KP-2) was resistant to imipenem, meropenem, and sulopenem (MICs of 16 to 32 μg/ml) while the other (KP-1) was susceptible (MIC of 0.5 μg/ml); both contained the blaACT-1, blaSHV-1, and blaTEM-1 β-lactamases. blaACT-1 in both strains was encoded on a large ∼150-kb plasmid. Both isolates contained an identical class 1 integron encoding resistance to aminoglycosides and chloramphenicol. They each had identical insertions in ompK35 and ompK36, resulting in disruption of these key porin genes. The carbapenem-resistant and -susceptible isolates were extensively studied for differences in the structural and regulatory genes for the operons acrRAB, marORAB, romA-ramA, soxRS, micF, micC, phoE, phoBR, rpoS, and hfq. No changes were detected between the isolates except for a significant down-regulation of ompK37, phoB, and phoE in KP-2 as deduced from reverse transcription-PCR analysis of mRNA and polyacrylamide gel electrophoresis separation of outer membrane proteins. Backcross analysis was conducted using the wild-type phoE gene cloned into the vector pGEM under regulation of its native promoter as well as the lacZ promoter following transformation into the resistant KP-2 isolate. The wild-type gene reversed carbapenem resistance only when under control of the heterologous lacZ promoter. In the background of ompK35-ompK36 gene disruption, the up-regulation of phoE in KP-1 apparently compensated for porin loss and conferred carbapenem susceptibility. Down-regulation of phoE in KP-2 may represent the normal state of this gene, or it may have been selected from KP-1 in vivo under antibiotic pressure

  20. High-level carbapenem resistance in a Klebsiella pneumoniae clinical isolate is due to the combination of bla(ACT-1) beta-lactamase production, porin OmpK35/36 insertional inactivation, and down-regulation of the phosphate transport porin phoe.

    PubMed

    Kaczmarek, Frank M; Dib-Hajj, Fadia; Shang, Wenchi; Gootz, Thomas D

    2006-10-01

    Clinical isolates of Klebsiella pneumoniae resistant to carbapenems and essentially all other antibiotics (multidrug resistant) are being isolated from some hospitals in New York City with increasing frequency. A highly related pair of K. pneumoniae strains isolated on the same day from one patient in a hospital in New York City were studied for antibiotic resistance. One (KP-2) was resistant to imipenem, meropenem, and sulopenem (MICs of 16 to 32 microg/ml) while the other (KP-1) was susceptible (MIC of 0.5 microg/ml); both contained the bla(ACT-1), bla(SHV-1), and bla(TEM-1) beta-lactamases. bla(ACT-1) in both strains was encoded on a large approximately 150-kb plasmid. Both isolates contained an identical class 1 integron encoding resistance to aminoglycosides and chloramphenicol. They each had identical insertions in ompK35 and ompK36, resulting in disruption of these key porin genes. The carbapenem-resistant and -susceptible isolates were extensively studied for differences in the structural and regulatory genes for the operons acrRAB, marORAB, romA-ramA, soxRS, micF, micC, phoE, phoBR, rpoS, and hfq. No changes were detected between the isolates except for a significant down-regulation of ompK37, phoB, and phoE in KP-2 as deduced from reverse transcription-PCR analysis of mRNA and polyacrylamide gel electrophoresis separation of outer membrane proteins. Backcross analysis was conducted using the wild-type phoE gene cloned into the vector pGEM under regulation of its native promoter as well as the lacZ promoter following transformation into the resistant KP-2 isolate. The wild-type gene reversed carbapenem resistance only when under control of the heterologous lacZ promoter. In the background of ompK35-ompK36 gene disruption, the up-regulation of phoE in KP-1 apparently compensated for porin loss and conferred carbapenem susceptibility. Down-regulation of phoE in KP-2 may represent the normal state of this gene, or it may have been selected from KP-1 in vivo

  1. Lycorine, the Main Phenanthridine Amaryllidaceae Alkaloid, Exhibits Significant Anti-Tumor Activity in Cancer Cells that Display Resistance to Proapoptotic Stimuli: an Investigation of Structure-Activity Relationship and Mechanistic Insight

    PubMed Central

    Lamoral-Theys, Delphine; Andolfi, Anna; Van Goietsenoven, Gwendoline; Cimmino, Alessio; Le Calvé, Benjamin; Wauthoz, Nathalie; Mégalizzi, Véronique; Gras, Thierry; Bruyère, Céline; Dubois, Jacques; Mathieu, Véronique; Kornienko, Alexander; Kiss, Robert; Evidente, Antonio

    2011-01-01

    Twenty-two lycorine-related compounds were investigated for in vitro anti-tumor activity using four cancer cell lines displaying different levels of resistance to pro-apoptotic stimuli and two cancer cell lines sensitive to pro-apoptotic stimuli. Lycorine and six of its congeners exhibited potency in the single-digit micromolar range, while no compound appeared more active than lycorine. Lycorine also displayed the highest potential (in vitro) therapeutic ratio, being at least 15 times more active against cancer than normal cells. Our studies also showed that lycorine exerts its in vitro anti-tumor activity through cytostatic rather than cytotoxic effects. Furthermore, lycorine provided significant therapeutic benefit in mice bearing brain grafts of the B16F10 melanoma model at non-toxic doses. Thus, the results of the current study make lycorine an excellent lead for the generation of compounds able to combat cancers, which are naturally resistant to pro-apoptotic stimuli, such as glioblastoma, melanoma, non-small-cell-lung cancers, metastatic cancers, among others. PMID:19788245

  2. Lycorine, the main phenanthridine Amaryllidaceae alkaloid, exhibits significant antitumor activity in cancer cells that display resistance to proapoptotic stimuli: an investigation of structure-activity relationship and mechanistic insight.

    PubMed

    Lamoral-Theys, Delphine; Andolfi, Anna; Van Goietsenoven, Gwendoline; Cimmino, Alessio; Le Calvé, Benjamin; Wauthoz, Nathalie; Mégalizzi, Véronique; Gras, Thierry; Bruyère, Céline; Dubois, Jacques; Mathieu, Véronique; Kornienko, Alexander; Kiss, Robert; Evidente, Antonio

    2009-10-22

    Twenty-two lycorine-related compounds were investigated for in vitro antitumor activity using four cancer cell lines displaying different levels of resistance to proapoptotic stimuli and two cancer cell lines sensitive to proapoptotic stimuli. Lycorine and six of its congeners exhibited potency in the single-digit micromolar range, while no compound appeared more active than lycorine. Lycorine also displayed the highest potential (in vitro) therapeutic ratio, being at least 15 times more active against cancer than normal cells. Our studies also showed that lycorine exerts its in vitro antitumor activity through cytostatic rather than cytotoxic effects. Furthermore, lycorine provided significant therapeutic benefit in mice bearing brain grafts of the B16F10 melanoma model at nontoxic doses. Thus, the results of the current study make lycorine an excellent lead for the generation of compounds able to combat cancers, which are naturally resistant to proapoptotic stimuli, such as glioblastoma, melanoma, non-small-cell-lung cancers, and metastatic cancers, among others.

  3. An Exhibit for Touching.

    ERIC Educational Resources Information Center

    Hunt, Susan

    1979-01-01

    An exhibit designed for visually handicapped persons presented by the Kalamazoo (Michigan) Institute of Art included bronze sculptures and oil paintings from the institute's permanent collection. (CL)

  4. An overview of very high level software design methods

    NASA Technical Reports Server (NTRS)

    Asdjodi, Maryam; Hooper, James W.

    1988-01-01

    Very High Level design methods emphasize automatic transfer of requirements to formal design specifications, and/or may concentrate on automatic transformation of formal design specifications that include some semantic information of the system into machine executable form. Very high level design methods range from general domain independent methods to approaches implementable for specific applications or domains. Applying AI techniques, abstract programming methods, domain heuristics, software engineering tools, library-based programming and other methods different approaches for higher level software design are being developed. Though one finds that a given approach does not always fall exactly in any specific class, this paper provides a classification for very high level design methods including examples for each class. These methods are analyzed and compared based on their basic approaches, strengths and feasibility for future expansion toward automatic development of software systems.

  5. A Teaching Aids Exhibition.

    ERIC Educational Resources Information Center

    Mahanja, Salah

    1985-01-01

    Describes an exhibition for the benefit of teachers of English in Arab Primary Schools, which was prepared by third-year students at the Teachers College for Arab Teachers. The exhibition included games, songs, audiovisual aids, crossword puzzles, vocabulary, spelling booklets, preposition aids, and worksheet and lesson planning aids. (SED)

  6. High Level Waste (HLW) Feed Process Control Strategy

    SciTech Connect

    STAEHR, T.W.

    2000-06-14

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

  7. High level radioactive waste management facility design criteria

    SciTech Connect

    Sheikh, N.A.; Salaymeh, S.R.

    1993-10-01

    This paper discusses the engineering systems for the structural design of the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS). At the DWPF, high level radioactive liquids will be mixed with glass particles and heated in a melter. This molten glass will then be poured into stainless steel canisters where it will harden. This process will transform the high level waste into a more stable, manageable substance. This paper discuss the structural design requirements for this unique one of a kind facility. A special emphasis will be concentrated on the design criteria pertaining to earthquake, wind and tornado, and flooding.

  8. Final report on cermet high-level waste forms

    SciTech Connect

    Kobisk, E.H.; Quinby, T.C.; Aaron, W.S.

    1981-08-01

    Cermets are being developed as an alternate method for the fixation of defense and commercial high level radioactive waste in a terminal disposal form. Following initial feasibility assessments of this waste form, consisting of ceramic particles dispersed in an iron-nickel base alloy, significantly improved processing methods were developed. The characterization of cermets has continued through property determinations on samples prepared by various methods from a variety of simulated and actual high-level wastes. This report describes the status of development of the cermet waste form as it has evolved since 1977. 6 tables, 18 figures.

  9. High-Level Event Recognition in Unconstrained Videos

    DTIC Science & Technology

    2013-01-01

    for polyphonic music. J Acoust Soc Am 122( 2 ):881–891 6. Aytar Y, ShahM, Luo J (2008) Utilizing semantic word similarity measures for video retrieval...Int J Multimed Info Retr (2013) 2 :73–101 DOI 10.1007/s13735-012-0024- 2 TRENDS AND SURVEYS High-level event recognition in unconstrained videos Yu...mob”). Techniques for recognizing such high-level events are essential for many practical applications such as Web video search, consumer video

  10. Communicating Science through Exhibitions

    NASA Astrophysics Data System (ADS)

    Dusenbery, P.; Harold, J.; Morrow, C.

    It is critically important for the public to better understand the scientific process. Museum exhibitions are an important part of informal science education that can effectively reach public audiences as well as school groups. They provide an important gateway for the public to learn about compelling scientific endeavors. There are many ways for scientists to help develop science exhibitions. The Space Science Institute (SSI) is a national leader in producing traveling science exhibitions and their associated educational programming (i.e. interactive websites, educator workshops, public talks, instructional materials). Two of its exhibitions, Space Weather Center and MarsQuest, are currently on tour. Another exhibition, Alien Earths, is in development. The Space Weather Center was developed in partnership with various research missions at NASA's Goddard Space Flight Center. MarsQuest is a 5000 square-foot traveling exhibition. The exhibit's second 3-year tour began this January at the Detroit Science Center. It is enabling millions of Americans to share in the excitement of the scientific exploration of Mars and to learn more about their own planet in the process. The 3,000 square-foot traveling exhibition, called Alien Earths, will bring origins-related research and discoveries to students and the American public. Alien Earths has four interrelated exhibit areas: Our Place in Space, Star Birth, PlanetQuest, and Search for Life. Exhibit visitors will explore the awesome events surrounding the birth of stars and planets; they will join scientists in the hunt for planets outside our solar system including those that may be in ``habitable zones'' around other stars; and finally they will be able to learn about how scientists are looking for signs of life beyond Earth. Besides the exhibits, SSI is also developing interactive web sites based on exhibit themes. New technologies are transforming the Web from a static medium to an interactive environment with tremendous

  11. New Hurricane Exhibit

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A new exhibit in StenniSphere depicting NASA's role in hurricane prediction and research and SSC's role in helping the region recover from Hurricane Katrina. The cyclone-shaped exhibit focuses on the effects of the Aug. 29, 2005 storm and outlines how NASA is working to improve weather forecasting. Through photos, 3-D models and digital animations, the exhibit tells the story of what happened inside the storm and how NASA's scientific research can increase the accuracy of hurricane tracking and modeling.

  12. High-Level Overview of Data Needs for RE Analysis

    SciTech Connect

    Lopez, Anthony

    2016-12-22

    This presentation provides a high level overview of analysis topics and associated data needs. Types of renewable energy analysis are grouped into two buckets: First, analysis for renewable energy potential, and second, analysis for other goals. Data requirements are similar but and they build upon one another.

  13. High-level manpower movement and Japan's foreign aid.

    PubMed

    Furuya, K

    1992-01-01

    "Japan's technical assistance programs to Asian countries are summarized. Movements of high-level manpower accompanying direct foreign investments by private enterprise are also reviewed. Proposals for increased human resources development include education and training of foreigners in Japan as well as the training of Japanese aid experts and the development of networks for information exchange."

  14. Typewriter Modifications for Persons Who Are High-Level Quadriplegics.

    ERIC Educational Resources Information Center

    O'Reagan, James R.; And Others

    Standard, common electric typewriters are not completely suited to the needs of a high-level quadriplegic typing with a mouthstick. Experiences show that for complete control of a typewriter a mouthstick user needs the combined features of one-button correction, electric forward and reverse indexing, and easy character viewing. To modify a…

  15. Structuring Peer Interaction To Promote High-Level Cognitive Processing.

    ERIC Educational Resources Information Center

    King, Alison

    2002-01-01

    Examines the kind of peer learning that demands high-level cognitive processing, discussing how peer interaction influences cognitive processes (structuring peer interaction and using guided reciprocal peer questioning); how to promote cognitive processing (knowledge construction and integration and socio- cognitive conflict); metacognition; and…

  16. A comparison of high-level waste form characteristics

    SciTech Connect

    Salmon, R.; Notz, K.J.

    1991-01-01

    There are currently about 1055 million curies of high-level waste with a thermal output of about 2950 kilowatts (KW) at four sites in the United States: West Valley Demonstration Project (WVDP), Savannah River Site (SRS), Hanford Site (HANF), and Idaho National Engineering Laboratory (INEL). These quantities are expected to increase to about 1200 million curies and 3570 kw by the end of year 2020. Under the Nuclear Waste Policy Act, this high-level waste must ultimately be disposed of in a geologic repository. Accordingly, canisters of high-level waste immobilized in borosilicate glass or glass-ceramic mixtures are to be produced at the four sites and stored there until a repository becomes available. Data on the estimated production schedules and on the physical, chemical, and radiological characteristics of the canisters of immobilized high-level waste have been collected in OCRWM's Waste Characteristics Data Base, including recent updates an revisions. Comparisons of some of these data for the four sites are presented in this report. 14 refs., 3 tabs.

  17. THE XAL INFRASTRUCTURE FOR HIGH LEVEL CONTROL ROOM APPLICATIONS

    SciTech Connect

    Shishlo, Andrei P; Allen, Christopher K; Chu, Paul; Galambos, John D; Pelaia II, Tom

    2009-01-01

    XAL is a Java programming framework for building high-level control applications related to accelerator physics. The structure, details of implementation, and interaction between components, auxiliary XAL packages, and the latest modifications are discussed. A general overview of XAL applications created for the SNS project is presented.

  18. High levels of virological failure with major genotypic resistance mutations in HIV-1-infected children after 5 years of care according to WHO-recommended 1st-line and 2nd-line antiretroviral regimens in the Central African Republic: A cross-sectional study.

    PubMed

    Mossoro-Kpinde, Christian Diamant; Gody, Jean-Chrysostome; Mboumba Bouassa, Ralph-Sydney; Mbitikon, Olivia; Jenabian, Mohammad-Ali; Robin, Leman; Matta, Mathieu; Zeitouni, Kamal; Longo, Jean De Dieu; Costiniuk, Cecilia; Grésenguet, Gérard; Touré Kane, Ndèye Coumba; Bélec, Laurent

    2017-03-01

    A large cohort of 220 HIV-1-infected children (median [range] age: 12 [4-17] years) was cared and followed up in the Central African Republic, including 198 in 1st-line and 22 in 2nd-line antiretroviral regimens. Patients were monitored clinically and biologically for HIV-1 RNA load and drug resistance mutations (DRMs) genotyping. A total of 87 (40%) study children were virological responders and 133 (60%) nonresponders. In children with detectable viral load, the majority (129; 97%) represented a virological failure. In children receiving 1st-line regimens in virological failure for whom genotypic resistance test was available, 45% displayed viruses harboring at least 1 DRM to NNRTI or NRTI, and 26% showed at least 1 major DRM to NNRTI or NRTI; more than half of children in 1st-line regimens were resistant to 1st-generation NNRTI and 24% of the children in 1st-line regimens had a major DRMs to PI. Virological failure and selection of DRMs were both associated with poor adherence. These observations demonstrate high rate of virological failure after 3 to 5 years of 1st-line or 2nd-line antiretroviral treatment, which is generally associated with DRMs and therapeutic failure. Overall, more than half (55%) of children receiving 1st-line antiretroviral treatment for a median of 3.4 years showed virological failure and antiretroviral-resistance and thus eligible to 2nd-line treatment. Furthermore, two-third (64%) of children under 2nd-line therapy were eligible to 3rd-line regimen. Taken together, these observations point the necessity to monitor antiretroviral-treated children by plasma HIV-1 RNA load to diagnose as early as possible the therapeutic failure and operate switch to a new therapeutic line.

  19. High levels of virological failure with major genotypic resistance mutations in HIV-1-infected children after 5 years of care according to WHO-recommended 1st-line and 2nd-line antiretroviral regimens in the Central African Republic

    PubMed Central

    Mossoro-Kpinde, Christian Diamant; Gody, Jean-Chrysostome; Mboumba Bouassa, Ralph-Sydney; Mbitikon, Olivia; Jenabian, Mohammad-Ali; Robin, Leman; Matta, Mathieu; Zeitouni, Kamal; Longo, Jean De Dieu; Costiniuk, Cecilia; Grésenguet, Gérard; Touré Kane, Ndèye Coumba; Bélec, Laurent

    2017-01-01

    Abstract A large cohort of 220 HIV-1-infected children (median [range] age: 12 [4–17] years) was cared and followed up in the Central African Republic, including 198 in 1st-line and 22 in 2nd-line antiretroviral regimens. Patients were monitored clinically and biologically for HIV-1 RNA load and drug resistance mutations (DRMs) genotyping. A total of 87 (40%) study children were virological responders and 133 (60%) nonresponders. In children with detectable viral load, the majority (129; 97%) represented a virological failure. In children receiving 1st-line regimens in virological failure for whom genotypic resistance test was available, 45% displayed viruses harboring at least 1 DRM to NNRTI or NRTI, and 26% showed at least 1 major DRM to NNRTI or NRTI; more than half of children in 1st-line regimens were resistant to 1st-generation NNRTI and 24% of the children in 1st-line regimens had a major DRMs to PI. Virological failure and selection of DRMs were both associated with poor adherence. These observations demonstrate high rate of virological failure after 3 to 5 years of 1st-line or 2nd-line antiretroviral treatment, which is generally associated with DRMs and therapeutic failure. Overall, more than half (55%) of children receiving 1st-line antiretroviral treatment for a median of 3.4 years showed virological failure and antiretroviral-resistance and thus eligible to 2nd-line treatment. Furthermore, two-third (64%) of children under 2nd-line therapy were eligible to 3rd-line regimen. Taken together, these observations point the necessity to monitor antiretroviral-treated children by plasma HIV-1 RNA load to diagnose as early as possible the therapeutic failure and operate switch to a new therapeutic line. PMID:28272247

  20. High-Level Waste Vitrification Facility Feasibility Study

    SciTech Connect

    D. A. Lopez

    1999-08-01

    A ''Settlement Agreement'' between the Department of Energy and the State of Idaho mandates that all radioactive high-level waste now stored at the Idaho Nuclear Technology and Engineering Center will be treated so that it is ready to be moved out of Idaho for disposal by a compliance date of 2035. This report investigates vitrification treatment of the high-level waste in a High-Level Waste Vitrification Facility based on the assumption that no more New Waste Calcining Facility campaigns will be conducted after June 2000. Under this option, the sodium-bearing waste remaining in the Idaho Nuclear Technology and Engineering Center Tank Farm, and newly generated liquid waste produced between now and the start of 2013, will be processed using a different option, such as a Cesium Ion Exchange Facility. The cesium-saturated waste from this other option will be sent to the Calcine Solids Storage Facilities to be mixed with existing calcine. The calcine and cesium-saturated waste will be processed in the High-Level Waste Vitrification Facility by the end of calendar year 2035. In addition, the High-Level Waste Vitrification Facility will process all newly-generated liquid waste produced between 2013 and the end of 2035. Vitrification of this waste is an acceptable treatment method for complying with the Settlement Agreement. This method involves vitrifying the waste and pouring it into stainless-steel canisters that will be ready for shipment out of Idaho to a disposal facility by 2035. These canisters will be stored at the Idaho National Engineering and Environmental Laboratory until they are sent to a national geologic repository. The operating period for vitrification treatment will be from the end of 2015 through 2035.

  1. Test Control Center exhibit

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Have you ever wondered how the engineers at John C. Stennis Space Center in Hancock County, Miss., test fire a Space Shuttle Main Engine? The Test Control Center exhibit at StenniSphere can answer your questions by simulating the test firing of a Space Shuttle Main Engine. A recreation of one of NASA's test control centers, the exhibit explains and portrays the 'shake, rattle and roar' that happens during a real test firing.

  2. Communicating Science through Exhibitions

    NASA Astrophysics Data System (ADS)

    Dusenbery, Paul

    2005-04-01

    It is critically important for the public to better understand the scientific process. Museum exhibitions are an important part of informal science education that can effectively reach public audiences as well as school groups. They provide an important gateway for the public to learn about compelling scientific endeavors. Science exhibitions also provide a marvelous opportunity for scientists to become engaged in the exhibit development process. The Space Science Institute (SSI) is a national leader in producing traveling science exhibitions and their associated educational programming (i.e. interactive websites, educator workshops, public talks, instructional materials). The focus of this presentation will be on two of its exhibit projects: MarsQuest (on tour for four years) and Alien Earths (its tour began early in 2005). MarsQuest is enabling millions of Americans to share in the excitement of the scientific exploration of Mars and to learn more about their own planet in the process. Alien Earths will bring origins-related research and discoveries to students and the American public. It has four interrelated exhibit areas: Our Place in Space, Star Birth, Planet Quest, and Search for Life. Exhibit visitors will explore the awesome events surrounding the birth of stars and planets; they will join scientists in the hunt for planets outside our solar system including those that may be in ``habitable zones'' around other stars; and finally they will be able to learn about how scientists are looking for signs of life beyond Earth. SSI is also developing interactive web sites based on exhibit themes. New technologies are transforming the Web from a static medium to an interactive environment with tremendous potential for informal education and inquiry-based investigations. This talk will focus on the role informal science projects play in effectively communicating science to a broad, public audience.

  3. Susceptibility of Drug-Resistant Clinical Herpes Simplex Virus Type 1 Strains to Essential Oils of Ginger, Thyme, Hyssop, and Sandalwood▿

    PubMed Central

    Schnitzler, Paul; Koch, Christine; Reichling, Jürgen

    2007-01-01

    Acyclovir-resistant clinical isolates of herpes simplex virus type 1 (HSV-1) were analyzed in vitro for their susceptibilities to essential oils of ginger, thyme, hyssop, and sandalwood. All essential oils exhibited high levels of virucidal activity against acyclovir-sensitive strain KOS and acyclovir-resistant HSV-1 clinical isolates and reduced plaque formation significantly. PMID:17353250

  4. Vaccine Vector for Sustained High-Level Antitumor CTL Response

    DTIC Science & Technology

    2011-01-01

    vector pCMV-Kan/neo which contains a CMV promoter immediately upstream of the insert site. A kanamycin resistant gene flanked by two FRT sequences...the entire MCMV genome and the NEU expression cassette. Following selection of recombinant BACs on the basis of kanamycin resistance, the Kan marker...was removed by flp-mediated recombination. [ polyA, polyadenylation site; Kan, kanamycin resistance gene for selection in bacteria; Frt, flp

  5. Multipurpose optimization models for high level waste vitrification

    SciTech Connect

    Hoza, M.

    1994-08-01

    Optimal Waste Loading (OWL) models have been developed as multipurpose tools for high-level waste studies for the Tank Waste Remediation Program at Hanford. Using nonlinear programming techniques, these models maximize the waste loading of the vitrified waste and optimize the glass formers composition such that the glass produced has the appropriate properties within the melter, and the resultant vitrified waste form meets the requirements for disposal. The OWL model can be used for a single waste stream or for blended streams. The models can determine optimal continuous blends or optimal discrete blends of a number of different wastes. The OWL models have been used to identify the most restrictive constraints, to evaluate prospective waste pretreatment methods, to formulate and evaluate blending strategies, and to determine the impacts of variability in the wastes. The OWL models will be used to aid in the design of frits and the maximize the waste in the glass for High-Level Waste (HLW) vitrification.

  6. RETENTION OF SULFATE IN HIGH LEVEL RADIOACTIVE WASTE GLASS

    SciTech Connect

    Fox, K.

    2010-09-07

    High level radioactive wastes are being vitrified at the Savannah River Site for long term disposal. Many of the wastes contain sulfate at concentrations that can be difficult to retain in borosilicate glass. This study involves efforts to optimize the composition of a glass frit for combination with the waste to improve sulfate retention while meeting other process and product performance constraints. The fabrication and characterization of several series of simulated waste glasses are described. The experiments are detailed chronologically, to provide insight into part of the engineering studies used in developing frit compositions for an operating high level waste vitrification facility. The results lead to the recommendation of a specific frit composition and a concentration limit for sulfate in the glass for the next batch of sludge to be processed at Savannah River.

  7. Management of data quality of high level waste characterization

    SciTech Connect

    Winters, W.I., Westinghouse Hanford

    1996-06-12

    Over the past 10 years, the Hanford Site has been transitioning from nuclear materials production to Site cleanup operations. High-level waste characterization at the Hanford Site provides data to support present waste processing operations, tank safety programs, and future waste disposal programs. Quality elements in the high-level waste characterization program will be presented by following a sample through the data quality objective, sampling, laboratory analysis and data review process. Transition from production to cleanup has resulted in changes in quality systems and program; the changes, as well as other issues in these quality programs, will be described. Laboratory assessment through quality control and performance evaluation programs will be described, and data assessments in the laboratory and final reporting in the tank characterization reports will be discussed.

  8. Life Extension of Aging High Level Waste (HLW) Tanks

    SciTech Connect

    BRYSON, D.

    2002-02-04

    The Double Shell Tanks (DSTs) play a critical role in the Hanford High-Level Waste Treatment Complex, and therefore activities are underway to protect and better understand these tanks. The DST Life Extension Program is focused on both tank life extension and on evaluation of tank integrity. Tank life extension activities focus on understanding tank failure modes and have produced key chemistry and operations controls to minimize tank corrosion and extend useful tank life. Tank integrity program activities have developed and applied key technologies to evaluate the condition of the tank structure and predict useful tank life. Program results to date indicate that DST useful life can be extended well beyond the original design life and allow the existing tanks to fill a critical function within the Hanford High-Level Waste Treatment Complex. In addition the tank life may now be more reliably predicted, facilitating improved planning for the use and possible future replacement of these tanks.

  9. Long-term high-level waste technology

    NASA Astrophysics Data System (ADS)

    Cornman, W. R.

    1980-07-01

    This series of reports summarizes research and development studies on the immobilization of high level wastes from the chemical reprocessing of nuclear reactor fuels. Immobilization of the wastes (defense and commercial) consists of placing them in a high integrity form with a very low potential for radionuclide release. Immobilization of commercial wastes is being considered on a contingency basis in the event that reprocessing is resumed. The basic plan for meeting the goal of immobilization of the DOE high level wastes is: (1) to develop technology to support a realistic choice of waste form alternatives for each of the three DOE sites; (2) to develop product and processing technology with sufficient scaleup to provide design data for full scale facilities; and (3) to construct and operate the facilities.

  10. Mixing Processes in High-Level Waste Tanks - Final Report

    SciTech Connect

    Peterson, P.F.

    1999-05-24

    The mixing processes in large, complex enclosures using one-dimensional differential equations, with transport in free and wall jets is modeled using standard integral techniques. With this goal in mind, we have constructed a simple, computationally efficient numerical tool, the Berkeley Mechanistic Mixing Model, which can be used to predict the transient evolution of fuel and oxygen concentrations in DOE high-level waste tanks following loss of ventilation, and validate the model against a series of experiments.

  11. Hierarchical High Level Information Fusion (H2LIFT)

    DTIC Science & Technology

    2008-09-15

    National Strategy for Maritime Security‖, 2005. 11. J. Morgan and B. Wimmer, ― Enhancing Awareness in the Maritime Domain‖, CHIPS Magazine, 14-15, 2005...Intelligence, vol. 18, no. 3, pp. 475–496, 2004. 30. K. Sambhoos, et al., ― Enhancements to high level data fusion using graph matching and state space search...range and bearing calculations over long distances. Loran -C and GPS navigation receivers use ellipsoidal earth models to compute position and waypoint

  12. Automatic rule generation for high-level vision

    NASA Technical Reports Server (NTRS)

    Rhee, Frank Chung-Hoon; Krishnapuram, Raghu

    1992-01-01

    Many high-level vision systems use rule-based approaches to solving problems such as autonomous navigation and image understanding. The rules are usually elaborated by experts. However, this procedure may be rather tedious. In this paper, we propose a method to generate such rules automatically from training data. The proposed method is also capable of filtering out irrelevant features and criteria from the rules.

  13. Trustworthy System Development Through High-Level Synthesis

    DTIC Science & Technology

    2014-09-01

    processor manufacturers have embraced the high-level synthesis ( HLS ) design philosophy. HLS offers the potential to explore the design space of electronic...circuits and systems more efficiently than traditional methods. In this thesis, we investigate the ap- plication of HLS to hardware-oriented security and...level synthesis ( HLS ) design phi- losophy. HLS offers the potential to explore the design space of electronic circuits and systems more efficiently than

  14. Case for retrievable high-level nuclear waste disposal

    USGS Publications Warehouse

    Roseboom, Eugene H.

    1994-01-01

    Plans for the nation's first high-level nuclear waste repository have called for permanently closing and sealing the repository soon after it is filled. However, the hydrologic environment of the proposed site at Yucca Mountain, Nevada, should allow the repository to be kept open and the waste retrievable indefinitely. This would allow direct monitoring of the repository and maintain the options for future generations to improve upon the disposal methods or use the uranium in the spent fuel as an energy resource.

  15. The tracking of high level waste shipments-TRANSCOM system

    SciTech Connect

    Johnson, P.E.; Joy, D.S.; Pope, R.B.

    1995-12-31

    The TRANSCOM (transportation tracking and communication) system is the U.S. Department of Energy`s (DOE`s) real-time system for tracking shipments of spent fuel, high-level wastes, and other high-visibility shipments of radioactive material. The TRANSCOM system has been operational since 1988. The system was used during FY1993 to track almost 100 shipments within the US.DOE complex, and it is accessed weekly by 10 to 20 users.

  16. Swamp to Space exhibit

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The menacing-looking alligator is really harmless. It is one of the realistic props to help convince visitors that the feel of the swamp is real in StenniSphere's Swamp to Space exhibit at John C. Stennis Space Center in Hancock County, Miss. The historical section of the Swamp to Space exhibit tells the story of why and how Stennis Space Center came to be. It also pays tribute to the families who moved their homes to make way for the space age in Mississippi.

  17. Handbook of high-level radioactive waste transportation

    SciTech Connect

    Sattler, L.R.

    1992-10-01

    The High-Level Radioactive Waste Transportation Handbook serves as a reference to which state officials and members of the general public may turn for information on radioactive waste transportation and on the federal government`s system for transporting this waste under the Civilian Radioactive Waste Management Program. The Handbook condenses and updates information contained in the Midwestern High-Level Radioactive Waste Transportation Primer. It is intended primarily to assist legislators who, in the future, may be called upon to enact legislation pertaining to the transportation of radioactive waste through their jurisdictions. The Handbook is divided into two sections. The first section places the federal government`s program for transporting radioactive waste in context. It provides background information on nuclear waste production in the United States and traces the emergence of federal policy for disposing of radioactive waste. The second section covers the history of radioactive waste transportation; summarizes major pieces of legislation pertaining to the transportation of radioactive waste; and provides an overview of the radioactive waste transportation program developed by the US Department of Energy (DOE). To supplement this information, a summary of pertinent federal and state legislation and a glossary of terms are included as appendices, as is a list of publications produced by the Midwestern Office of The Council of State Governments (CSG-MW) as part of the Midwestern High-Level Radioactive Waste Transportation Project.

  18. High level cognitive information processing in neural networks

    NASA Technical Reports Server (NTRS)

    Barnden, John A.; Fields, Christopher A.

    1992-01-01

    Two related research efforts were addressed: (1) high-level connectionist cognitive modeling; and (2) local neural circuit modeling. The goals of the first effort were to develop connectionist models of high-level cognitive processes such as problem solving or natural language understanding, and to understand the computational requirements of such models. The goals of the second effort were to develop biologically-realistic model of local neural circuits, and to understand the computational behavior of such models. In keeping with the nature of NASA's Innovative Research Program, all the work conducted under the grant was highly innovative. For instance, the following ideas, all summarized, are contributions to the study of connectionist/neural networks: (1) the temporal-winner-take-all, relative-position encoding, and pattern-similarity association techniques; (2) the importation of logical combinators into connection; (3) the use of analogy-based reasoning as a bridge across the gap between the traditional symbolic paradigm and the connectionist paradigm; and (4) the application of connectionism to the domain of belief representation/reasoning. The work on local neural circuit modeling also departs significantly from the work of related researchers. In particular, its concentration on low-level neural phenomena that could support high-level cognitive processing is unusual within the area of biological local circuit modeling, and also serves to expand the horizons of the artificial neural net field.

  19. Pictures at an Exhibition.

    ERIC Educational Resources Information Center

    Kunz, Walter S., Jr.

    1997-01-01

    Describes the Youth Art Month exhibit in Howard County (Maryland) where students submitted their art focusing on school buildings and their interiors. Their art reveals concerns and desires about overcrowding, space utilization, school building height, outside lighting, solitude needs, and visual stimulation. The artwork is discussed in terms of…

  20. Exhibitions in Sight.

    ERIC Educational Resources Information Center

    Wasserman, Burton

    1978-01-01

    Early in the eighteenth century, Pompeii was discovered, a city that had been hidden for sixteen centuries by volcanic lava. There is a traveling exhibition of the sculptures, friezes, mosaics, and paintings being shown around the United States. Described is the history and contents of "Pompeii--A.D. 79." (RK)

  1. 1989 Architectural Exhibition Winners.

    ERIC Educational Resources Information Center

    School Business Affairs, 1990

    1990-01-01

    Winners of the 1989 Architectural Exhibition sponsored annually by the ASBO International's School Facilities Research Committee include the Brevard Performing Arts Center (Melbourne, Florida), the Capital High School (Santa Fe, New Mexico), Gage Elementary School (Rochester, Minnesota), the Lakewood (Ohio) High School Natatorium, and three other…

  2. Exhibition in Sight

    ERIC Educational Resources Information Center

    Wasserman, Burton

    1978-01-01

    Ludwig Mies van der Rohe is known primarily as an architect. However, he also designed chairs and tables. Discusses an exhibit held in New York City a few months ago which showed how well the famous architect achieved his goals in the area of furniture design. (Author/RK)

  3. Crevice corrosion and pitting of high-level waste containers: Integration of deterministic and probabilistic models

    SciTech Connect

    Farmer, J.C.; McCright, R.D.

    1998-12-31

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as carbon steel or Alloy 400. An integrated predictive model is being developed to account for the effects of localized environmental conditions in the CRM-CAM crevice on the initiation and propagation of pits through the CRM.

  4. Crevice corrosion {ampersand} pitting of high-level waste containers: integration of deterministic {ampersand} probabilistic models

    SciTech Connect

    Farmer, J.C.; McCright, R.D.

    1997-10-01

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as carbon steel or Monel 400. An integrated predictive model is being developed to account for the effects of localized environmental conditions in the CRM-CAM crevice on the initiation and propagation of pits through the CRM.

  5. CREVICE CORROSION & PITTING OF HIGH-LEVEL WASTE CONTAINERS: INTEGRATION OF DETERMINISTIC & PROBABILISTIC MODELS

    SciTech Connect

    JOSEPH C. FARMER AND R. DANIEL MCCRIGHT

    1997-10-01

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as carbon steel or Monel 400. An integrated predictive model is being developed to account for the effects of localized environmental conditions in the CRM-CAM crevice on the initiation and propagation of pits through the CRM.

  6. Screening and incorporation of rust resistance from Allium cepa into bunching onion (Allium fistulosum) via alien chromosome addition.

    PubMed

    Wako, Tadayuki; Yamashita, Ken-ichiro; Tsukazaki, Hikaru; Ohara, Takayoshi; Kojima, Akio; Yaguchi, Shigenori; Shimazaki, Satoshi; Midorikawa, Naoko; Sakai, Takako; Yamauchi, Naoki; Shigyo, Masayoshi

    2015-04-01

    Bunching onion (Allium fistulosum L.; 2n = 16), bulb onion (Allium cepa L. Common onion group), and shallot (Allium cepa L. Aggregatum group) cultivars were inoculated with rust fungus, Puccinia allii, isolated from bunching onion. Bulb onions and shallots are highly resistant to rust, suggesting they would serve as useful resources for breeding rust resistant bunching onions. To identify the A. cepa chromosome(s) related to rust resistance, a complete set of eight A. fistulosum - shallot monosomic alien addition lines (MAALs) were inoculated with P. allii. At the seedling stage, FF+1A showed a high level of resistance in controlled-environment experiments, suggesting that the genes related to rust resistance could be located on shallot chromosome 1A. While MAAL, multi-chromosome addition line, and hypoallotriploid adult plants did not exhibit strong resistance to rust. In contrast to the high resistance of shallot, the addition line FF+1A+5A showed reproducibly high levels of rust resistance.

  7. Starship 2040 Exhibit

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This photograph shows the Starship 2040 leaving the Marshall Space Flight Center (MSFC) for the exhibit site. Developed by the Space Transportation Directorate at MSFC, the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit, automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids and emergency and safety systems, are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a 'real' Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

  8. Starship 2040 Exhibit

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This photograph shows onlookers viewing displays within the Starship 2040 exhibit on display at Joe Davis Stadium in Huntsville, Alabama. Developed by the Space Transportation Directorate at Marshall Space Flight Center (MSFC), the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit (automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids, and emergency and safety systems) are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the Nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a 'real' Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

  9. Starship 2040 Exhibit

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This photograph shows Justin Varnadore, son of a Marshall TV employee, at the controls of one of the many displays within the Starship 2040 exhibit on display at Joe Davis Stadium in Huntsville, Alabama. Developed by the Space Transportation Directorate at Marshall Space Flight Center (MSFC), the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit (automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids, and emergency and safety systems) are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the Nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a 'real' Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

  10. Development of a High Level Waste Tank Inspection System

    SciTech Connect

    Appel, D.K.; Loibl, M.W.; Meese, D.C.

    1995-03-21

    The Westinghouse Savannah River Technology Center was requested by it`s sister site, West Valley Nuclear Service (WVNS), to develop a remote inspection system to gather wall thickness readings of their High Level Waste Tanks. WVNS management chose to take a proactive approach to gain current information on two tanks t hat had been in service since the early 70`s. The tanks contain high level waste, are buried underground, and have only two access ports to an annular space between the tank and the secondary concrete vault. A specialized remote system was proposed to provide both a visual surveillance and ultrasonic thickness measurements of the tank walls. A magnetic wheeled crawler was the basis for the remote delivery system integrated with an off-the-shelf Ultrasonic Data Acquisition System. A development program was initiated for Savannah River Technology Center (SRTC) to design, fabricate, and test a remote system based on the Crawler. The system was completed and involved three crawlers to perform the needed tasks, an Ultrasonic Crawler, a Camera Crawler, and a Surface Prep Crawler. The crawlers were computer controlled so that their operation could be done remotely and their position on the wall could be tracked. The Ultrasonic Crawler controls were interfaced with ABB Amdata`s I-PC, Ultrasonic Data Acquisition System so that thickness mapping of the wall could be obtained. A second system was requested by Westinghouse Savannah River Company (WSRC), to perform just ultrasonic mapping on their similar Waste Storage Tanks; however, the system needed to be interfaced with the P-scan Ultrasonic Data Acquisition System. Both remote inspection systems were completed 9/94. Qualifications tests were conducted by WVNS prior to implementation on the actual tank and tank development was achieved 10/94. The second inspection system was deployed at WSRC 11/94 with success, and the system is now in continuous service inspecting the remaining high level waste tanks at WSRC.

  11. High-level waste management technology program plan

    SciTech Connect

    Harmon, H.D.

    1995-01-01

    The purpose of this plan is to document the integrated technology program plan for the Savannah River Site (SRS) High-Level Waste (HLW) Management System. The mission of the SRS HLW System is to receive and store SRS high-level wastes in a see and environmentally sound, and to convert these wastes into forms suitable for final disposal. These final disposal forms are borosilicate glass to be sent to the Federal Repository, Saltstone grout to be disposed of on site, and treated waste water to be released to the environment via a permitted outfall. Thus, the technology development activities described herein are those activities required to enable successful accomplishment of this mission. The technology program is based on specific needs of the SRS HLW System and organized following the systems engineering level 3 functions. Technology needs for each level 3 function are listed as reference, enhancements, and alternatives. Finally, FY-95 funding, deliverables, and schedules are s in Chapter IV with details on the specific tasks that are funded in FY-95 provided in Appendix A. The information in this report represents the vision of activities as defined at the beginning of the fiscal year. Depending on emergent issues, funding changes, and other factors, programs and milestones may be adjusted during the fiscal year. The FY-95 SRS HLW technology program strongly emphasizes startup support for the Defense Waste Processing Facility and In-Tank Precipitation. Closure of technical issues associated with these operations has been given highest priority. Consequently, efforts on longer term enhancements and alternatives are receiving minimal funding. However, High-Level Waste Management is committed to participation in the national Radioactive Waste Tank Remediation Technology Focus Area. 4 refs., 5 figs., 9 tabs.

  12. Modeling of Boehmite Leaching from Actual Hanford High-Level Waste Samples

    SciTech Connect

    Peterson, Reid A.; Lumetta, Gregg J.; Rapko, Brian M.; Poloski, Adam P.

    2007-06-27

    The Department of Energy plans to vitrify approximately 60,000 metric tons of high level waste sludge from underground storage tanks at the Hanford Nuclear Reservation. To reduce the volume of high level waste requiring treatment, a goal has been set to remove about 90 percent of the aluminum, which comprises nearly 70 percent of the sludge. Aluminum in the form of gibbsite and sodium aluminate can be easily dissolved by washing the waste stream with caustic, but boehmite, which comprises nearly half of the total aluminum, is more resistant to caustic dissolution and requires higher treatment temperatures and hydroxide concentrations. In this work, the dissolution kinetics of aluminum species during caustic leaching of actual Hanford high level waste samples is examined. The experimental results are used to develop a shrinking core model that provides a basis for prediction of dissolution dynamics from known process temperature and hydroxide concentration. This model is further developed to include the effects of particle size polydispersity, which is found to strongly influence the rate of dissolution.

  13. High-level neutron coincidence counter maintenance manual

    SciTech Connect

    Swansen, J.; Collinsworth, P.

    1983-05-01

    High-level neutron coincidence counter operational (field) calibration and usage is well known. This manual makes explicit basic (shop) check-out, calibration, and testing of new units and is a guide for repair of failed in-service units. Operational criteria for the major electronic functions are detailed, as are adjustments and calibration procedures, and recurrent mechanical/electromechanical problems are addressed. Some system tests are included for quality assurance. Data on nonstandard large-scale integrated (circuit) components and a schematic set are also included.

  14. Market Designs for High Levels of Variable Generation: Preprint

    SciTech Connect

    Milligan, M.; Holttinen, H.; Kiviluoma, J.; Orths, A.; Lynch, M.; Soder, L.

    2014-10-01

    Variable renewable generation is increasing in penetration in modern power systems, leading to higher variability in the supply and price of electricity as well as lower average spot prices. This raises new challenges, particularly in ensuring sufficient capacity and flexibility from conventional technologies. Because the fixed costs and lifetimes of electricity generation investments are significant, designing markets and regulations that ensure the efficient integration of renewable generation is a significant challenge. This papers reviews the state of play of market designs for high levels of variable generation in the United States and Europe and considers new developments in both regions.

  15. Modern Alchemy: Solidifying high-level nuclear waste

    SciTech Connect

    Newton, C.C.

    1997-07-01

    The U.S. Department of Energy is putting a modern version of alchemy to work to produce an answer to a decades-old problem. It is taking place at the Savannah River Site (SRS) in Aiken, South Carolina and at the West Valley Demonstration Project (WVDP) near Buffalo, New York. At both locations, contractor Westinghouse Electric Corporation is applying technology that is turning liquid high-level radioactive waste (HLW) into a stabilized, durable glass for safer and easier management. The process is called vitrification. SRS and WVDP are now operating the nation`s first full-scale HLW vitrification plants.

  16. Corrosion and failure processes in high-level waste tanks

    SciTech Connect

    Mahidhara, R.K.; Elleman, T.S.; Murty, K.L.

    1992-11-01

    A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

  17. High-level wastes: DOE names three sites for characterization

    SciTech Connect

    1986-07-01

    DOE announced in May 1986 that there will be there site characterization studies made to determine suitability for a high-level radioactive waste repository. The studies will include several test drillings to the proposed disposal depths. Yucca Mountain, Nevada; Deaf Smith Country, Texas, and Hanford, Washington were identified as the study sites, and further studies for a second repository site in the East were postponed. The affected states all filed suits in federal circuit courts because they were given no advance warning of the announcement of their selection or the decision to suspend work on a second repository. Criticisms of the selection process include the narrowing or DOE options.

  18. Online Exhibits & Concept Maps

    NASA Astrophysics Data System (ADS)

    Douma, M.

    2009-12-01

    Presenting the complexity of geosciences to the public via the Internet poses a number of challenges. For example, utilizing various - and sometimes redundant - Web 2.0 tools can quickly devour limited time. Do you tweet? Do you write press releases? Do you create an exhibit or concept map? The presentation will provide participants with a context for utilizing Web 2.0 tools by briefly highlighting methods of online scientific communication across several dimensions. It will address issues of: * breadth and depth (e.g. from narrow topics to well-rounded views), * presentation methods (e.g. from text to multimedia, from momentary to enduring), * sources and audiences (e.g. for experts or for the public, content developed by producers to that developed by users), * content display (e.g. from linear to non-linear, from instructive to entertaining), * barriers to entry (e.g. from an incumbent advantage to neophyte accessible, from amateur to professional), * cost and reach (e.g. from cheap to expensive), and * impact (e.g. the amount learned, from anonymity to brand awareness). Against this backdrop, the presentation will provide an overview of two methods of online information dissemination, exhibits and concept maps, using the WebExhibits online museum (www.webexhibits.org) and SpicyNodes information visualization tool (www.spicynodes.org) as examples, with tips on how geoscientists can use either to communicate their science. Richly interactive online exhibits can serve to engage a large audience, appeal to visitors with multiple learning styles, prompt exploration and discovery, and present a topic’s breadth and depth. WebExhibits, which was among the first online museums, delivers interactive information, virtual experiments, and hands-on activities to the public. While large, multidisciplinary exhibits on topics like “Color Vision and Art” or “Calendars Through the Ages” require teams of scholars, user interface experts, professional writers and editors

  19. Burning high-level TRU waste in fusion fission reactors

    NASA Astrophysics Data System (ADS)

    Shen, Yaosong

    2016-09-01

    Recently, the concept of actinide burning instead of a once-through fuel cycle for disposing spent nuclear fuel seems to get much more attention. A new method of burning high-level transuranic (TRU) waste combined with Thorium-Uranium (Th-U) fuel in the subcritical reactors driven by external fusion neutron sources is proposed in this paper. The thorium-based TRU fuel burns all of the long-lived actinides via a hard neutron spectrum while outputting power. A one-dimensional model of the reactor concept was built by means of the ONESN_BURN code with new data libraries. The numerical results included actinide radioactivity, biological hazard potential, and much higher burnup rate of high-level transuranic waste. The comparison of the fusion-fission reactor with the thermal reactor shows that the harder neutron spectrum is more efficient than the soft. The Th-U cycle produces less TRU, less radiotoxicity and fewer long-lived actinides. The Th-U cycle provides breeding of 233U with a long operation time (>20 years), hence significantly reducing the reactivity swing while improving safety and burnup.

  20. Learning high-level features for chord recognition using Autoencoder

    NASA Astrophysics Data System (ADS)

    Phongthongloa, Vilailukkana; Kamonsantiroj, Suwatchai; Pipanmaekaporn, Luepol

    2016-07-01

    Chord transcription is valuable to do by itself. It is known that the manual transcription of chords is very tiresome, time-consuming. It requires, moreover, musical knowledge. Automatic chord recognition has recently attracted a number of researches in the Music Information Retrieval field. It has known that a pitch class profile (PCP) is the commonly signal representation of musical harmonic analysis. However, the PCP may contain additional non-harmonic noise such as harmonic overtones and transient noise. The problem of non-harmonic might be generating the sound energy in term of frequency more than the actual notes of the respective chord. Autoencoder neural network may be trained to learn a mapping from low level feature to one or more higher-level representation. These high-level representations can explain dependencies of the inputs and reduce the effect of non-harmonic noise. Then these improve features are fed into neural network classifier. The proposed high-level musical features show 80.90% of accuracy. The experimental results have shown that the proposed approach can achieve better performance in comparison with other based method.

  1. High level language-based robotic control system

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo (Inventor); Kreutz, Kenneth K. (Inventor); Jain, Abhinandan (Inventor)

    1996-01-01

    This invention is a robot control system based on a high level language implementing a spatial operator algebra. There are two high level languages included within the system. At the highest level, applications programs can be written in a robot-oriented applications language including broad operators such as MOVE and GRASP. The robot-oriented applications language statements are translated into statements in the spatial operator algebra language. Programming can also take place using the spatial operator algebra language. The statements in the spatial operator algebra language from either source are then translated into machine language statements for execution by a digital control computer. The system also includes the capability of executing the control code sequences in a simulation mode before actual execution to assure proper action at execution time. The robot's environment is checked as part of the process and dynamic reconfiguration is also possible. The languages and system allow the programming and control of multiple arms and the use of inward/outward spatial recursions in which every computational step can be related to a transformation from one point in the mechanical robot to another point to name two major advantages.

  2. High level language-based robotic control system

    NASA Technical Reports Server (NTRS)

    Rodriguez, Guillermo (Inventor); Kruetz, Kenneth K. (Inventor); Jain, Abhinandan (Inventor)

    1994-01-01

    This invention is a robot control system based on a high level language implementing a spatial operator algebra. There are two high level languages included within the system. At the highest level, applications programs can be written in a robot-oriented applications language including broad operators such as MOVE and GRASP. The robot-oriented applications language statements are translated into statements in the spatial operator algebra language. Programming can also take place using the spatial operator algebra language. The statements in the spatial operator algebra language from either source are then translated into machine language statements for execution by a digital control computer. The system also includes the capability of executing the control code sequences in a simulation mode before actual execution to assure proper action at execution time. The robot's environment is checked as part of the process and dynamic reconfiguration is also possible. The languages and system allow the programming and control of multiple arms and the use of inward/outward spatial recursions in which every computational step can be related to a transformation from one point in the mechanical robot to another point to name two major advantages.

  3. Local acceptance of a high-level nuclear waste repository.

    PubMed

    Sjöberg, Lennart

    2004-06-01

    The siting of nuclear waste facilities has been very difficult in all countries. Recent experience in Sweden indicates, however, that it may be possible, under certain circumstances, to gain local support for the siting of a high-level nuclear waste (HLNW) repository. The article reports on a study of attitudes and risk perceptions of people living in four municipalities in Sweden where HLNW siting was being intensely discussed at the political level, in media, and among the public. Data showed a relatively high level of consensus on acceptability of at least further investigation of the issue; in two cases local councils have since voted in favor of a go-ahead, and in one case only a very small majority defeated the issue. Models of policy attitudes showed that these were related to attitude to nuclear power, attributes of the perceived HLNW risk, and trust. Factors responsible for acceptance are discussed at several levels. One is the attitude to nuclear power, which is becoming more positive, probably because no viable alternatives are in sight. Other factors have to do with the extensive information programs conducted in these municipalities, and with the logical nature of the conclusion that they would be good candidates for hosting the national HLNW repository.

  4. VITRIFICATION OF HIGH LEVEL WASTE AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Fox, K.; Peeler, D.

    2009-06-17

    The objective of this study was to experimentally measure the properties and performance of a series of glasses with compositions that could represent high level waste Sludge Batch 5 (SB5) as vitrified at the Savannah River Site Defense Waste Processing Facility. These data were used to guide frit optimization efforts as the SB5 composition was finalized. Glass compositions for this study were developed by combining a series of SB5 composition projections with a group of candidate frits. The study glasses were fabricated using depleted uranium and their chemical compositions, crystalline contents and chemical durabilities were characterized. Trevorite was the only crystalline phase that was identified in a few of the study glasses after slow cooling, and is not of concern as spinels have been shown to have little impact on the durability of high level waste glasses. Chemical durability was quantified using the Product Consistency Test (PCT). All of the glasses had very acceptable durability performance. The results of this study indicate that a frit composition can be identified that will provide a processable and durable glass when combined with SB5.

  5. High level radioactive waste glass production and product description

    SciTech Connect

    Sproull, J.F.; Marra, S.L.; Jantzen, C.M.

    1993-12-01

    This report examines borosilicate glass as a means of immobilizing high-level radioactive wastes. Borosilicate glass will encapsulate most of the defense and some of the commercial HLW in the US. The resulting waste forms must meet the requirements of the WA-SRD and the WAPS, which include a short term PCT durability test. The waste form producer must report the composition(s) of the borosilicate waste glass(es) produced but can choose the composition(s) to meet site-specific requirements. Although the waste form composition is the primary determinant of durability, the redox state of the glass; the existence, content, and composition of crystals; and the presence of glass-in-glass phase separation can affect durability. The waste glass should be formulated to avoid phase separation regions. The ultimate result of this effort will be a waste form which is much more stable and potentially less mobile than the liquid high level radioactive waste is currently.

  6. Spent fuel and high-level radioactive waste transportation report

    SciTech Connect

    Not Available

    1989-11-01

    This publication is intended to provide its readers with an introduction to the issues surrounding the subject of transportation of spent nuclear fuel and high-level radioactive waste, especially as those issues impact the southern region of the United States. It was originally issued by the Southern States Energy Board (SSEB) in July 1987 as the Spent Nuclear Fuel and High-Level Radioactive Waste Transportation Primer, a document patterned on work performed by the Western Interstate Energy Board and designed as a ``comprehensive overview of the issues.`` This work differs from that earlier effort in that it is designed for the educated layman with little or no background in nuclear waste issues. In addition, this document is not a comprehensive examination of nuclear waste issues but should instead serve as a general introduction to the subject. Owing to changes in the nuclear waste management system, program activities by the US Department of Energy and other federal agencies and developing technologies, much of this information is dated quickly. While this report uses the most recent data available, readers should keep in mind that some of the material is subject to rapid change. SSEB plans periodic updates in the future to account for changes in the program. Replacement pages sew be supplied to all parties in receipt of this publication provided they remain on the SSEB mailing list.

  7. How to achieve high-level expression of microbial enzymes

    PubMed Central

    Liu, Long; Yang, Haiquan; Shin, Hyun-dong; Chen, Rachel R.; Li, Jianghua; Du, Guocheng; Chen, Jian

    2013-01-01

    Microbial enzymes have been used in a large number of fields, such as chemical, agricultural and biopharmaceutical industries. The enzyme production rate and yield are the main factors to consider when choosing the appropriate expression system for the production of recombinant proteins. Recombinant enzymes have been expressed in bacteria (e.g., Escherichia coli, Bacillus and lactic acid bacteria), filamentous fungi (e.g., Aspergillus) and yeasts (e.g., Pichia pastoris). The favorable and very advantageous characteristics of these species have resulted in an increasing number of biotechnological applications. Bacterial hosts (e.g., E. coli) can be used to quickly and easily overexpress recombinant enzymes; however, bacterial systems cannot express very large proteins and proteins that require post-translational modifications. The main bacterial expression hosts, with the exception of lactic acid bacteria and filamentous fungi, can produce several toxins which are not compatible with the expression of recombinant enzymes in food and drugs. However, due to the multiplicity of the physiological impacts arising from high-level expression of genes encoding the enzymes and expression hosts, the goal of overproduction can hardly be achieved, and therefore, the yield of recombinant enzymes is limited. In this review, the recent strategies used for the high-level expression of microbial enzymes in the hosts mentioned above are summarized and the prospects are also discussed. We hope this review will contribute to the development of the enzyme-related research field. PMID:23686280

  8. Spent fuel and high-level radioactive waste transportation report

    SciTech Connect

    Not Available

    1990-11-01

    This publication is intended to provide its readers with an introduction to the issues surrounding the subject of transportation of spent nuclear fuel and high-level radioactive waste, especially as those issues impact the southern region of the United States. It was originally issued by the Southern States Energy Board (SSEB) in July 1987 as the Spent Nuclear Fuel and High-Level Radioactive Waste Transportation Primer, a document patterned on work performed by the Western Interstate Energy Board and designed as a ``comprehensive overview of the issues.`` This work differs from that earlier effort in that it is designed for the educated layman with little or no background in nuclear waste issues. In addition, this document is not a comprehensive examination of nuclear waste issues but should instead serve as a general introduction to the subject. Owing to changes in the nuclear waste management system, program activities by the US Department of Energy and other federal agencies and developing technologies, much of this information is dated quickly. While this report uses the most recent data available, readers should keep in mind that some of the material is subject to rapid change. SSEB plans periodic updates in the future to account for changes in the program. Replacement pages will be supplied to all parties in receipt of this publication provided they remain on the SSEB mailing list.

  9. FLUIDIZED BED STEAM REFORMING ENABLING ORGANIC HIGH LEVEL WASTE DISPOSAL

    SciTech Connect

    Williams, M

    2008-05-09

    Waste streams planned for generation by the Global Nuclear Energy Partnership (GNEP) and existing radioactive High Level Waste (HLW) streams containing organic compounds such as the Tank 48H waste stream at Savannah River Site have completed simulant and radioactive testing, respectfully, by Savannah River National Laboratory (SRNL). GNEP waste streams will include up to 53 wt% organic compounds and nitrates up to 56 wt%. Decomposition of high nitrate streams requires reducing conditions, e.g. provided by organic additives such as sugar or coal, to reduce NOX in the off-gas to N2 to meet Clean Air Act (CAA) standards during processing. Thus, organics will be present during the waste form stabilization process regardless of the GNEP processes utilized and exists in some of the high level radioactive waste tanks at Savannah River Site and Hanford Tank Farms, e.g. organics in the feed or organics used for nitrate destruction. Waste streams containing high organic concentrations cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by pretreatment. The alternative waste stabilization pretreatment process of Fluidized Bed Steam Reforming (FBSR) operates at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). The FBSR process has been demonstrated on GNEP simulated waste and radioactive waste containing high organics from Tank 48H to convert organics to CAA compliant gases, create no secondary liquid waste streams and create a stable mineral waste form.

  10. Space augmentation of military high-level waste disposal

    NASA Technical Reports Server (NTRS)

    English, T.; Lees, L.; Divita, E.

    1979-01-01

    Space disposal of selected components of military high-level waste (HLW) is considered. This disposal option offers the promise of eliminating the long-lived radionuclides in military HLW from the earth. A space mission which meets the dual requirements of long-term orbital stability and a maximum of one space shuttle launch per week over a period of 20-40 years, is a heliocentric orbit about halfway between the orbits of earth and Venus. Space disposal of high-level radioactive waste is characterized by long-term predictability and short-term uncertainties which must be reduced to acceptably low levels. For example, failure of either the Orbit Transfer Vehicle after leaving low earth orbit, or the storable propellant stage failure at perihelion would leave the nuclear waste package in an unplanned and potentially unstable orbit. Since potential earth reencounter and subsequent burn-up in the earth's atmosphere is unacceptable, a deep space rendezvous, docking, and retrieval capability must be developed.

  11. Status of high-level waste processing at West Valley

    SciTech Connect

    Howell, A.J.; Baker, M.N. )

    1991-11-01

    The US Department of Energy is charged with the solidification of high-level liquid waste remaining from nuclear fuel reprocessing activities that were conducted at West Valley, New York, between 1966 and 1972. The 2.27 million liters (600,000 gal) of waste in an underground storage tank has separated into a sludge layer, {approximately}10% of the original volume, and a liquid layer. Prior to the high-level waste (HLW) vitrification, volume reduction of the waste is necessary. Sine May 1988, West Valley has successfully processed >1.59 million liters (420,000 gal) of HLW. Processing to date has involved the removal of {sup 139}Cs from the HLW effluent by ion exchange, evaporation to concentrate the effluent to a predetermined salt concentration, and finally cementation. This process has removed {approximately}80% of the {sup 137}Cs from the HLW liquid phase. Modifications are currently being made to begin the second phase of the HLW processing at West Valley. The second phase of HLW processing will include the removal of plutonium as well as cesium from the HLW sludge. This paper describes the progress made to date and the modifications being made to the process and to the feed stream to begin the second phase of HLW processing.

  12. Permitting plan for the high-level waste interim storage

    SciTech Connect

    Deffenbaugh, M.L.

    1997-04-23

    This document addresses the environmental permitting requirements for the transportation and interim storage of solidified high-level waste (HLW) produced during Phase 1 of the Hanford Site privatization effort. Solidified HLW consists of canisters containing vitrified HLW (glass) and containers that hold cesium separated during low-level waste pretreatment. The glass canisters and cesium containers will be transported to the Canister Storage Building (CSB) in a U.S. Department of Energy (DOE)-provided transportation cask via diesel-powered tractor trailer. Tri-Party Agreement (TPA) Milestone M-90 establishes a new major milestone, and associated interim milestones and target dates, governing acquisition and/or modification of facilities necessary for: (1) interim storage of Tank Waste Remediation Systems (TWRS) immobilized HLW (IHLW) and other canistered high-level waste forms; and (2) interim storage and disposal of TWRS immobilized low-activity tank waste (ILAW). An environmental requirements checklist and narrative was developed to identify the permitting path forward for the HLW interim storage (HLWIS) project (See Appendix B). This permitting plan will follow the permitting logic developed in that checklist.

  13. Space Shuttle Cockpit exhibit

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Want to sit in the cockpit of the Space Shuttle and watch astronauts work in outer space? At StenniSphere, you can do that and much more. StenniSphere, the visitor center at John C. Stennis Space Center in Hancock County, Miss., presents 14,000-square-feet of interactive exhibits that depict America's race for space as well as a glimpse of the future. StenniSphere is open free of charge from 9 a.m. to 5 p.m. daily.

  14. Wide-Range Temperature Sensors with High-Level Pulse Train Output

    NASA Technical Reports Server (NTRS)

    Hammoud, Ahmad; Patterson, Richard L.

    2009-01-01

    Two types of temperature sensors have been developed for wide-range temperature applications. The two sensors measure temperature in the range of -190 to +200 C and utilize a thin-film platinum RTD (resistance temperature detector) as the temperature-sensing element. Other parts used in the fabrication of these sensors include NPO (negative-positive- zero) type ceramic capacitors for timing, thermally-stable film or wirewound resistors, and high-temperature circuit boards and solder. The first type of temperature sensor is a relaxation oscillator circuit using an SOI (silicon-on-insulator) operational amplifier as a comparator. The output is a pulse train with a period that is roughly proportional to the temperature being measured. The voltage level of the pulse train is high-level, for example 10 V. The high-level output makes the sensor less sensitive to noise or electromagnetic interference. The output can be read by a frequency or period meter and then converted into a temperature reading. The second type of temperature sensor is made up of various types of multivibrator circuits using an SOI type 555 timer and the passive components mentioned above. Three configurations have been developed that were based on the technique of charging and discharging a capacitor through a resistive element to create a train of pulses governed by the capacitor-resistor time constant. Both types of sensors, which operated successfully over the wide temperature range, have potential use in extreme temperature environments including jet engines and space exploration missions.

  15. Strontium and Actinide Separations from High Level Nuclear Waste Solutions using Monosodium Titanate - Actual Waste Testing

    SciTech Connect

    Peters, T.B.; Barnes, M.J.; Hobbs,D.T.; Walker, D.D.; Fondeur, F.F.; Norato, M.A.; Pulmano, R.L.; Fink, S.D.

    2005-11-01

    Pretreatment processes at the Savannah River Site will separate {sup 90}Sr, alpha-emitting and radionuclides (i.e., actinides) and {sup 137}Cs prior to disposal of the high-level nuclear waste. Separation of {sup 90}Sr and alpha-emitting radionuclides occurs by ion exchange/adsorption using an inorganic material, monosodium titanate (MST). Previously reported testing with simulants indicates that the MST exhibits high selectivity for strontium and actinides in high ionic strength and strongly alkaline salt solutions. This paper provides a summary of data acquired to measure the performance of MST to remove strontium and actinides from actual waste solutions. These tests evaluated the effects of ionic strength, mixing, elevated alpha activities, and multiple contacts of the waste with MST. Tests also provided confirmation that MST performs well at much larger laboratory scales (300-700 times larger) and exhibits little affinity for desorption of strontium and plutonium during washing.

  16. Starship 2040 Exhibit

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This photograph shows the Starship 2040 on display at Joe Davis Stadium in Huntsville, Alabama. Developed by the Space Transportation Directorate at Marshall Space Flight Center (MSFC), the Starship 2040 exhibit is housed in a 48-ft (14.6-m) tractor and trailer rig, permitting it to travel around the Nation, demonstrating NASA's vision of what commercial spaceflight might be like 40 years from now. All the irnovations suggested aboard the exhibit (automated vehicle health monitoring systems, high-energy propulsion drive, navigational aids, and emergency and safety systems) are based on concepts and technologies now being studied at NASA Centers and partner institutions around the Nation. NASA is the Nation's premier agency for development of the space transportation system, including future-generation reusable launch vehicles. Such systems, the keys to a 'real' Starship 2040, require revolutionary advances in critical aerospace technologies, from thermal, magnetic, chemical, and propellantless propulsion systems to new energy sources such as space solar power or antimatter propulsion. These and other advances are now being studied, developed, and tested at NASA field centers and partner institutions all over the Nation.

  17. High-Level Language Production in Parkinson's Disease: A Review

    PubMed Central

    Altmann, Lori J. P.; Troche, Michelle S.

    2011-01-01

    This paper discusses impairments of high-level, complex language production in Parkinson's disease (PD), defined as sentence and discourse production, and situates these impairments within the framework of current psycholinguistic theories of language production. The paper comprises three major sections, an overview of the effects of PD on the brain and cognition, a review of the literature on language production in PD, and a discussion of the stages of the language production process that are impaired in PD. Overall, the literature converges on a few common characteristics of language production in PD: reduced information content, impaired grammaticality, disrupted fluency, and reduced syntactic complexity. Many studies also document the strong impact of differences in cognitive ability on language production. Based on the data, PD affects all stages of language production including conceptualization and functional and positional processing. Furthermore, impairments at all stages appear to be exacerbated by impairments in cognitive abilities. PMID:21860777

  18. A high-level language for rule-based modelling.

    PubMed

    Pedersen, Michael; Phillips, Andrew; Plotkin, Gordon D

    2015-01-01

    Rule-based languages such as Kappa excel in their support for handling the combinatorial complexities prevalent in many biological systems, including signalling pathways. But Kappa provides little structure for organising rules, and large models can therefore be hard to read and maintain. This paper introduces a high-level, modular extension of Kappa called LBS-κ. We demonstrate the constructs of the language through examples and three case studies: a chemotaxis switch ring, a MAPK cascade, and an insulin signalling pathway. We then provide a formal definition of LBS-κ through an abstract syntax and a translation to plain Kappa. The translation is implemented in a compiler tool which is available as a web application. We finally demonstrate how to increase the expressivity of LBS-κ through embedded scripts in a general-purpose programming language, a technique which we view as generally applicable to other domain specific languages.

  19. Midwestern High-Level Radioactive Waste Transportation Project

    SciTech Connect

    Dantoin, T.S.

    1990-12-01

    For more than half a century, the Council of State Governments has served as a common ground for the states of the nation. The Council is a nonprofit, state-supported and -directed service organization that provides research and resources, identifies trends, supplies answers and creates a network for legislative, executive and judicial branch representatives. This List of Available Resources was prepared with the support of the US Department of Energy, Cooperative Agreement No. DE-FC02-89CH10402. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of DOE. The purpose of the agreement, and reports issued pursuant to it, is to identify and analyze regional issues pertaining to the transportation of high-level radioactive waste and to inform Midwestern state officials with respect to technical issues and regulatory concerns related to waste transportation.

  20. The SEISMED High Level Security Policy for Health Care.

    PubMed

    Katsikas, S K

    1996-01-01

    The proliferation of the use of automated Health Information Systems in the everyday practice of health professionals has brought a number of issues related to the security of health information to a critical point. The preservation of security of health-related information can only be achieved through a concerted approach, comprising legal, organisational, technical and educational actions. These classes of actions constitute a complete "security framework", a key aspect of which is the set of rules, laws and regulations that govern the usage of information within a Health Care Establishment. This set is commonly referred to as "Security Policy". In this paper, the SEISMED High Level Security Policy for Health Care Establishments is presented.

  1. High Level Waste System Impacts from Acid Dissolution of Sludge

    SciTech Connect

    KETUSKY, EDWARD

    2006-04-20

    This research evaluates the ability of OLI{copyright} equilibrium based software to forecast Savannah River Site High Level Waste system impacts from oxalic acid dissolution of Tank 1-15 sludge heels. Without further laboratory and field testing, only the use of oxalic acid can be considered plausible to support sludge heel dissolution on multiple tanks. Using OLI{copyright} and available test results, a dissolution model is constructed and validated. Material and energy balances, coupled with the model, identify potential safety concerns. Overpressurization and overheating are shown to be unlikely. Corrosion induced hydrogen could, however, overwhelm the tank ventilation. While pH adjustment can restore the minimal hydrogen generation, resultant precipitates will notably increase the sludge volume. OLI{copyright} is used to develop a flowsheet such that additional sludge vitrification canisters and other negative system impacts are minimized. Sensitivity analyses are used to assess the processability impacts from variations in the sludge/quantities of acids.

  2. High-level theoretical rovibrational spectroscopy of HCS+ isotopologues

    NASA Astrophysics Data System (ADS)

    Schröder, B.; Sebald, P.

    2016-12-01

    In this work the rovibrational spectrum of the HCS+ molecular cation is revisited through high-level electronic structure and variational rovibrational calculations. A local potential energy function is built from explicitly correlated coupled-cluster results, incorporating corrections for core-valence, scalar relativistic and higher-order excitation effects. The computed spectroscopic parameters, based on variational calculations with Watson's isomorphic Hamiltonian for linear molecules lead to a nearly perfect agreement with experimentally reported values (Rosenbaum et al., 1989). Furthermore, the documented Fermi resonance within the (0,00, 1) / (0,20, 0) and (1,00, 1) / (1,20, 0) pairs of states is clarified. Based on a newly developed electric dipole moment function transition dipole moments of fundamental transitions are predicted for the most important isotopologues.

  3. High level radioactive waste vitrification process equipment component testing

    SciTech Connect

    Siemens, D.H.; Heath, W.O.; Larson, D.E.; Craig, S.N.; Berger, D.N.; Goles, R.W.

    1985-04-01

    Remote operability and maintainability of vitrification equipment were assessed under shielded-cell conditions. The equipment tested will be applied to immobilize high-level and transuranic liquid waste slurries that resulted from plutonium production for defense weapons. Equipment tested included: a turntable for handling waste canisters under the melter; a removable discharge cone in the melter overflow section; a thermocouple jumper that extends into a shielded cell; remote instrument and electrical connectors; remote, mechanical, and heat transfer aspects of the melter glass overflow section; a reamer to clean out plugged nozzles in the melter top; a closed circuit camera to view the melter interior; and a device to retrieve samples of the glass product. A test was also conducted to evaluate liquid metals for use in a liquid metal sealing system.

  4. Quasimonomorphic mononucleotide repeats for high-level microsatellite instability analysis.

    PubMed

    Buhard, Olivier; Suraweera, Nirosha; Lectard, Aude; Duval, Alex; Hamelin, Richard

    2004-01-01

    Microsatellite instability (MSI) analysis is becoming more and more important to detect sporadic primary tumors of the MSI phenotype as well as in helping to determine Hereditary Non-Polyposis Colorectal Cancer (HNPCC) cases. After some years of conflicting data due to the absence of consensus markers for the MSI phenotype, a meeting held in Bethesda to clarify the situation proposed a set of 5 microsatellites (2 mononucleotide repeats and 3 dinucleotide repeats) to determine MSI tumors. A second Bethesda consensus meeting was held at the end of 2002. It was discussed here that the 1998 microsatellite panel could underestimate high-level MSI tumors and overestimate low-level MSI tumors. Amongst the suggested changes was the exclusive use of mononucleotide repeats in place of dinucleotide repeats. We have already proposed a pentaplex MSI screening test comprising 5 quasimonomorphic mononucleotide repeats. This article compares the advantages of mono or dinucleotide repeats in determining microsatellite instability.

  5. Quasimonomorphic Mononucleotide Repeats for High-Level Microsatellite Instability Analysis

    PubMed Central

    Buhard, Olivier; Suraweera, Nirosha; Lectard, Aude; Duval, Alex; Hamelin, Richard

    2004-01-01

    Microsatellite instability (MSI) analysis is becoming more and more important to detect sporadic primary tumors of the MSI phenotype as well as in helping to determine Hereditary Non-Polyposis Colorectal Cancer (HNPCC) cases. After some years of conflicting data due to the absence of consensus markers for the MSI phenotype, a meeting held in Bethesda to clarify the situation proposed a set of 5 microsatellites (2 mononucleotide repeats and 3 dinucleotide repeats) to determine MSI tumors. A second Bethesda consensus meeting was held at the end of 2002. It was discussed here that the 1998 microsatellite panel could underestimate high-level MSI tumors and overestimate low-level MSI tumors. Amongst the suggested changes was the exclusive use of mononucleotide repeats in place of dinucleotide repeats. We have already proposed a pentaplex MSI screening test comprising 5 quasimonomorphic mononucleotide repeats. This article compares the advantages of mono or dinucleotide repeats in determining microsatellite instability. PMID:15528790

  6. Socioeconomic studies of high-level nuclear waste disposal.

    PubMed Central

    White, G F; Bronzini, M S; Colglazier, E W; Dohrenwend, B; Erikson, K; Hansen, R; Kneese, A V; Moore, R; Page, E B; Rappaport, R A

    1994-01-01

    The socioeconomic investigations of possible impacts of the proposed repository for high-level nuclear waste at Yucca Mountain, Nevada, have been unprecedented in several respects. They bear on the public decision that sooner or later will be made as to where and how to dispose permanently of the waste presently at military weapons installations and that continues to accumulate at nuclear power stations. No final decision has yet been made. There is no clear precedent from other countries. The organization of state and federal studies is unique. The state studies involve more disciplines than any previous efforts. They have been carried out in parallel to federal studies and have pioneered in defining some problems and appropriate research methods. A recent annotated bibliography provides interested scientists with a compact guide to the 178 published reports, as well as to relevant journal articles and related documents. PMID:7971963

  7. SIMULANT DEVELOPMENT FOR SAVANNAH RIVER SITE HIGH LEVEL WASTE

    SciTech Connect

    Stone, M; Russell Eibling, R; David Koopman, D; Dan Lambert, D; Paul Burket, P

    2007-09-04

    The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The HLW is processed in large batches through DWPF; DWPF has recently completed processing Sludge Batch 3 (SB3) and is currently processing Sludge Batch 4 (SB4). The composition of metal species in SB4 is shown in Table 1 as a function of the ratio of a metal to iron. Simulants remove radioactive species and renormalize the remaining species. Supernate composition is shown in Table 2.

  8. Exceptionally high levels of multiple mating in an army ant

    NASA Astrophysics Data System (ADS)

    Denny, A. Jay; Franks, Nigel R.; Powell, Scott; Edwards, Keith J.

    Most species of social insects have singly mated queens, although there are notable exceptions. Competing hypotheses have been proposed to explain the evolution of high levels of multiple mating, but this issue is far from resolved. Here we use microsatellites to investigate mating frequency in the army ant Eciton burchellii and show that queens mate with an exceptionally large number of males, eclipsing all but one other social insect species for which data are available. In addition we present evidence that suggests that mating is serial, continuing throughout the lifetime of the queen. This is the first demonstration of serial mating among social hymenoptera. We propose that high paternity within colonies is most likely to have evolved to increase genetic diversity and to counter high pathogen and parasite loads.

  9. Review of High Level Waste Tanks Ultrasonic Inspection Data

    SciTech Connect

    Wiersma, B

    2006-03-09

    A review of the data collected during ultrasonic inspection of the Type I high level waste tanks has been completed. The data was analyzed for relevance to the possibility of vapor space corrosion and liquid/air interface corrosion. The review of the Type I tank UT inspection data has confirmed that the vapor space general corrosion is not an unusually aggressive phenomena and correlates well with predicted corrosion rates for steel exposed to bulk solution. The corrosion rates are seen to decrease with time as expected. The review of the temperature data did not reveal any obvious correlations between high temperatures and the occurrences of leaks. The complex nature of temperature-humidity interaction, particularly with respect to vapor corrosion requires further understanding to infer any correlation. The review of the waste level data also did not reveal any obvious correlations.

  10. Reinforcement learning for high-level fuzzy Petri nets.

    PubMed

    Shen, V L

    2003-01-01

    The author has developed a reinforcement learning algorithm for the high-level fuzzy Petri net (HLFPN) models in order to perform structure and parameter learning simultaneously. In addition to the HLFPN itself, the difference and similarity among a variety of subclasses concerning Petri nets are also discussed. As compared with the fuzzy adaptive learning control network (FALCON), the HLFPN model preserves the advantages that: 1) it offers more flexible learning capability because it is able to model both IF-THEN and IF-THEN-ELSE rules; 2) it allows multiple heterogeneous outputs to be drawn if they exist; 3) it offers a more compact data structure for fuzzy production rules so as to save information storage; and 4) it is able to learn faster due to its structural reduction. Finally, main results are presented in the form of seven propositions and supported by some experiments.

  11. ALICE: Project Overview and High Level Science Products

    NASA Astrophysics Data System (ADS)

    Soummer, Remi; Choquet, Elodie; Pueyo, Laurent; Brendan Hagan, J.; Gofas-Salas, Elena; Rajan, Abhijith; Perrin, Marshall D.; Chen, Christine; Debes, John H.; Golimowski, David A.; Hines, Dean C.; Schneider, Glenn; N'Diaye, Mamadou; Mawet, Dimitri; Marois, Christian; Barman, Travis

    2015-01-01

    We report on the status of the ALICE project (Archival Legacy Investigation of Circumstellar Environments), which consists in a consistent reanalysis of the entire HST-NICMOS coronagraphic archive. Over the last two years, we have developed a sophisticated pipeline able to handle the data of the 400 stars of the archive. This pipeline builds on the Karhunen-Loeve Image Projection (KLIP) algorithm, and was completed in the fall of 2014. We discuss the first processing and analysis results of the overall reduction campaign. As we will deliver high-level science products to the STScI MAST archive, we are defining a new standard format for high-contrast science products, which will be compatible with every new high-contrast imaging instrument (GPI, SPHERE, P1640, CHARIS, etc.) and used by the JWST coronagraphs. We present here the specifications of this standard.

  12. High-level waste tank farm set point document

    SciTech Connect

    Anthony, J.A. III

    1995-01-15

    Setpoints for nuclear safety-related instrumentation are required for actions determined by the design authorization basis. Minimum requirements need to be established for assuring that setpoints are established and held within specified limits. This document establishes the controlling methodology for changing setpoints of all classifications. The instrumentation under consideration involve the transfer, storage, and volume reduction of radioactive liquid waste in the F- and H-Area High-Level Radioactive Waste Tank Farms. The setpoint document will encompass the PROCESS AREA listed in the Safety Analysis Report (SAR) (DPSTSA-200-10 Sup 18) which includes the diversion box HDB-8 facility. In addition to the PROCESS AREAS listed in the SAR, Building 299-H and the Effluent Transfer Facility (ETF) are also included in the scope.

  13. High Level Information Fusion (HLIF) with nested fusion loops

    NASA Astrophysics Data System (ADS)

    Woodley, Robert; Gosnell, Michael; Fischer, Amber

    2013-05-01

    Situation modeling and threat prediction require higher levels of data fusion in order to provide actionable information. Beyond the sensor data and sources the analyst has access to, the use of out-sourced and re-sourced data is becoming common. Through the years, some common frameworks have emerged for dealing with information fusion—perhaps the most ubiquitous being the JDL Data Fusion Group and their initial 4-level data fusion model. Since these initial developments, numerous models of information fusion have emerged, hoping to better capture the human-centric process of data analyses within a machine-centric framework. 21st Century Systems, Inc. has developed Fusion with Uncertainty Reasoning using Nested Assessment Characterizer Elements (FURNACE) to address challenges of high level information fusion and handle bias, ambiguity, and uncertainty (BAU) for Situation Modeling, Threat Modeling, and Threat Prediction. It combines JDL fusion levels with nested fusion loops and state-of-the-art data reasoning. Initial research has shown that FURNACE is able to reduce BAU and improve the fusion process by allowing high level information fusion (HLIF) to affect lower levels without the double counting of information or other biasing issues. The initial FURNACE project was focused on the underlying algorithms to produce a fusion system able to handle BAU and repurposed data in a cohesive manner. FURNACE supports analyst's efforts to develop situation models, threat models, and threat predictions to increase situational awareness of the battlespace. FURNACE will not only revolutionize the military intelligence realm, but also benefit the larger homeland defense, law enforcement, and business intelligence markets.

  14. High-level waste melter alternatives assessment report

    SciTech Connect

    Calmus, R.B.

    1995-02-01

    This document describes the Tank Waste Remediation System (TWRS) High-Level Waste (HLW) Program`s (hereafter referred to as HLW Program) Melter Candidate Assessment Activity performed in fiscal year (FY) 1994. The mission of the TWRS Program is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and encapsulated strontium and cesium isotopic sources) in an environmentally sound, safe, and cost-effective manner. The goal of the HLW Program is to immobilize the HLW fraction of pretreated tank waste into a vitrified product suitable for interim onsite storage and eventual offsite disposal at a geologic repository. Preparation of the encapsulated strontium and cesium isotopic sources for final disposal is also included in the HLW Program. As a result of trade studies performed in 1992 and 1993, processes planned for pretreatment of tank wastes were modified substantially because of increasing estimates of the quantity of high-level and transuranic tank waste remaining after pretreatment. This resulted in substantial increases in needed vitrification plant capacity compared to the capacity of original Hanford Waste Vitrification Plant (HWVP). The required capacity has not been finalized, but is expected to be four to eight times that of the HWVP design. The increased capacity requirements for the HLW vitrification plant`s melter prompted the assessment of candidate high-capacity HLW melter technologies to determine the most viable candidates and the required development and testing (D and T) focus required to select the Hanford Site HLW vitrification plant melter system. An assessment process was developed in early 1994. This document describes the assessment team, roles of team members, the phased assessment process and results, resulting recommendations, and the implementation strategy.

  15. High-level waste program integration within the DOE complex

    SciTech Connect

    Valentine, J.H.; Davis, N.R.; Malone, K.; Schaus, P.S.

    1998-03-01

    Eleven major Department of Energy (DOE) site contractors were chartered by the Assistant Secretary to use a systems engineering approach to develop and evaluate technically defensible cost savings opportunities across the complex. Known as the complex-wide Environmental Management Integration (EMI), this process evaluated all the major DOE waste streams including high level waste (HLW). Across the DOE complex, this waste stream has the highest life cycle cost and is scheduled to take until at least 2035 before all HLW is processed for disposal. Technical contract experts from the four DOE sites that manage high level waste participated in the integration analysis: Hanford, Savannah River Site (SRS), Idaho National Engineering and Environmental Laboratory (INEEL), and West Valley Demonstration Project (WVDP). In addition, subject matter experts from the Yucca Mountain Project and the Tanks Focus Area participated in the analysis. Also, departmental representatives from the US Department of Energy Headquarters (DOE-HQ) monitored the analysis and results. Workouts were held throughout the year to develop recommendations to achieve a complex-wide integrated program. From this effort, the HLW Environmental Management (EM) Team identified a set of programmatic and technical opportunities that could result in potential cost savings and avoidance in excess of $18 billion and an accelerated completion of the HLW mission by seven years. The cost savings, schedule improvements, and volume reduction are attributed to a multifaceted HLW treatment disposal strategy which involves waste pretreatment, standardized waste matrices, risk-based retrieval, early development and deployment of a shipping system for glass canisters, and reasonable, low cost tank closure.

  16. Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

    SciTech Connect

    Farmer, J.C.; Van Konynenburg, R.A.; McCright, R.D. ); Bullen, D.B. )

    1988-04-01

    Three iron- to nickel-based austenitic alloys (Types 304L and 316L stainless steels and Alloy 825) are being considered as candidate materials for the fabrication of high-level radioactive-waste containers. Waste will include fuel assemblies from reactors as well as high-level waste in borosilicate glass forms, and will be sent to the prospective repository at Yucca Mountain, Nevada. The decay of radionuclides in the repository will result in the generation of substantial heat and in fluences of gamma radiation. Container materials may undergo any of several modes of degradation in this environment, including atmospheric oxidation; uniform aqueous phase corrosion; pitting; crevice corrosion; sensitization and intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This report is an analysis of data relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of the three austenitic candidate alloys. The candidates are compared in terms of their susceptibilities to these forms of corrosion. Although all three candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these types of localized corrosion (LC); such resistance is important because pits can penetrate the metal and serve as crack initiation sites. Both Types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented in Alloy 825 under comparable conditions. Gamma radiation has been found to enhance SCC in Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while the effects of microbiologically induced corrosion have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. 211 refs., 49 figs., 10 tabs.

  17. Creating a Positive School Climate at the Junior High Level.

    ERIC Educational Resources Information Center

    Licata, Vincent F.

    One of the seven correlates of an effective school, as identified by the Effective Schools Research, is a positive school climate: a positive attitude on the part of the entire staff and student body exhibited through overt behavior that creates a warm, orderly learning environment. Development of such an environment depends upon: (1) strong…

  18. EstDZ3: A New Esterolytic Enzyme Exhibiting Remarkable Thermostability

    PubMed Central

    Zarafeta, Dimitra; Szabo, Zalan; Moschidi, Danai; Phan, Hien; Chrysina, Evangelia D.; Peng, Xu; Ingham, Colin J.; Kolisis, Fragiskos N.; Skretas, Georgios

    2016-01-01

    Lipolytic enzymes that retain high levels of catalytic activity when exposed to a variety of denaturing conditions are of high importance for a number of biotechnological applications. In this study, we aimed to identify new lipolytic enzymes, which are highly resistant to prolonged exposure to elevated temperatures. To achieve this, we searched for genes encoding for such proteins in the genomes of a microbial consortium residing in a hot spring located in China. After performing functional genomic screening on a bacterium of the genus Dictyoglomus, which was isolated from this hot spring following in situ enrichment, we identified a new esterolytic enzyme, termed EstDZ3. Detailed biochemical characterization of the recombinant enzyme, revealed that it constitutes a slightly alkalophilic and highly active esterase against esters of fatty acids with short to medium chain lengths. Importantly, EstDZ3 exhibits remarkable thermostability, as it retains high levels of catalytic activity after exposure to temperatures as high as 95°C for several hours. Furthermore, it exhibits very good stability against exposure to high concentrations of a variety of organic solvents. Interestingly, EstDZ3 was found to have very little similarity to previously characterized esterolytic enzymes. Computational modeling of the three-dimensional structure of this new enzyme predicted that it exhibits a typical α/β hydrolase fold that seems to include a “subdomain insertion”, which is similar to the one present in its closest homolog of known function and structure, the cinnamoyl esterase Lj0536 from Lactobacillus johnsonii. As it was found in the case of Lj0536, this structural feature is expected to be an important determinant of the catalytic properties of EstDZ3. The high levels of esterolytic activity of EstDZ3, combined with its remarkable thermostability and good stability against a range of organic solvents and other denaturing agents, render this new enzyme a candidate

  19. Spent nuclear fuel project high-level information management plan

    SciTech Connect

    Main, G.C.

    1996-09-13

    This document presents the results of the Spent Nuclear Fuel Project (SNFP) Information Management Planning Project (IMPP), a short-term project that identified information management (IM) issues and opportunities within the SNFP and outlined a high-level plan to address them. This high-level plan for the SNMFP IM focuses on specific examples from within the SNFP. The plan`s recommendations can be characterized in several ways. Some recommendations address specific challenges that the SNFP faces. Others form the basis for making smooth transitions in several important IM areas. Still others identify areas where further study and planning are indicated. The team`s knowledge of developments in the IM industry and at the Hanford Site were crucial in deciding where to recommend that the SNFP act and where they should wait for Site plans to be made. Because of the fast pace of the SNFP and demands on SNFP staff, input and interaction were primarily between the IMPP team and members of the SNFP Information Management Steering Committee (IMSC). Key input to the IMPP came from a workshop where IMSC members and their delegates developed a set of draft IM principles. These principles, described in Section 2, became the foundation for the recommendations found in the transition plan outlined in Section 5. Availability of SNFP staff was limited, so project documents were used as a basis for much of the work. The team, realizing that the status of the project and the environment are continually changing, tried to keep abreast of major developments since those documents were generated. To the extent possible, the information contained in this document is current as of the end of fiscal year (FY) 1995. Programs and organizations on the Hanford Site as a whole are trying to maximize their return on IM investments. They are coordinating IM activities and trying to leverage existing capabilities. However, the SNFP cannot just rely on Sitewide activities to meet its IM requirements

  20. Interventions for Individuals With High Levels of Needle Fear

    PubMed Central

    Noel, Melanie; Taddio, Anna; Antony, Martin M.; Asmundson, Gordon J.G.; Riddell, Rebecca Pillai; Chambers, Christine T.; Shah, Vibhuti

    2015-01-01

    Background: This systematic review evaluated the effectiveness of exposure-based psychological and physical interventions for the management of high levels of needle fear and/or phobia and fainting in children and adults. Design/Methods: A systematic review identified relevant randomized and quasi-randomized controlled trials of children, adults, or both with high levels of needle fear, including phobia (if not available, then populations with other specific phobias were included). Critically important outcomes were self-reported fear specific to the feared situation and stimulus (psychological interventions) or fainting (applied muscle tension). Data were pooled using standardized mean difference (SMD) or relative risk with 95% confidence intervals. Results: The systematic review included 11 trials. In vivo exposure-based therapy for children 7 years and above showed benefit on specific fear (n=234; SMD: −1.71 [95% CI: −2.72, −0.7]). In vivo exposure-based therapy with adults reduced fear of needles posttreatment (n=20; SMD: −1.09 [−2.04, −0.14]) but not at 1-year follow-up (n=20; SMD: −0.28 [−1.16, 0.6]). Compared with single session, a benefit was observed for multiple sessions of exposure-based therapy posttreatment (n=93; SMD: −0.66 [−1.08, −0.24]) but not after 1 year (n=83; SMD: −0.37 [−0.87, 0.13]). Non in vivo e.g., imaginal exposure-based therapy in children reduced specific fear posttreatment (n=41; SMD: −0.88 [−1.7, −0.05]) and at 3 months (n=24; SMD: −0.89 [−1.73, −0.04]). Non in vivo exposure-based therapy for adults showed benefit on specific fear (n=68; SMD: −0.62 [−1.11, −0.14]) but not procedural fear (n=17; SMD: 0.18 [−0.87, 1.23]). Applied tension showed benefit on fainting posttreatment (n=20; SMD: −1.16 [−2.12, −0.19]) and after 1 year (n=20; SMD: −0.97 [−1.91, −0.03]) compared with exposure alone. Conclusions: Exposure-based psychological interventions and applied muscle tension show

  1. CEMENTITIOUS GROUT FOR CLOSING SRS HIGH LEVEL WASTE TANKS - #12315

    SciTech Connect

    Langton, C.; Burns, H.; Stefanko, D.

    2012-01-10

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. The closure will also fill, physically stabilize and isolate ancillary equipment abandoned in the tanks. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and chemically reduction potential (Eh) of -200 to -400 to stabilize selected potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted, respectively, to support the mass placement strategy developed by closure

  2. Defense High-Level Waste Leaching Mechanisms Program. Final report

    SciTech Connect

    Mendel, J.E.

    1984-08-01

    The Defense High-Level Waste Leaching Mechanisms Program brought six major US laboratories together for three years of cooperative research. The participants reached a consensus that solubility of the leached glass species, particularly solubility in the altered surface layer, is the dominant factor controlling the leaching behavior of defense waste glass in a system in which the flow of leachant is constrained, as it will be in a deep geologic repository. Also, once the surface of waste glass is contacted by ground water, the kinetics of establishing solubility control are relatively rapid. The concentrations of leached species reach saturation, or steady-state concentrations, within a few months to a year at 70 to 90/sup 0/C. Thus, reaction kinetics, which were the main subject of earlier leaching mechanisms studies, are now shown to assume much less importance. The dominance of solubility means that the leach rate is, in fact, directly proportional to ground water flow rate. Doubling the flow rate doubles the effective leach rate. This relationship is expected to obtain in most, if not all, repository situations.

  3. High-Level Performance Modeling of SAR Systems

    NASA Technical Reports Server (NTRS)

    Chen, Curtis

    2006-01-01

    SAUSAGE (Still Another Utility for SAR Analysis that s General and Extensible) is a computer program for modeling (see figure) the performance of synthetic- aperture radar (SAR) or interferometric synthetic-aperture radar (InSAR or IFSAR) systems. The user is assumed to be familiar with the basic principles of SAR imaging and interferometry. Given design parameters (e.g., altitude, power, and bandwidth) that characterize a radar system, the software predicts various performance metrics (e.g., signal-to-noise ratio and resolution). SAUSAGE is intended to be a general software tool for quick, high-level evaluation of radar designs; it is not meant to capture all the subtleties, nuances, and particulars of specific systems. SAUSAGE was written to facilitate the exploration of engineering tradeoffs within the multidimensional space of design parameters. Typically, this space is examined through an iterative process of adjusting the values of the design parameters and examining the effects of the adjustments on the overall performance of the system at each iteration. The software is designed to be modular and extensible to enable consideration of a variety of operating modes and antenna beam patterns, including, for example, strip-map and spotlight SAR acquisitions, polarimetry, burst modes, and squinted geometries.

  4. Wind resource quality affected by high levels of renewables

    DOE PAGES

    Diakov, Victor

    2015-06-17

    For solar photovoltaic (PV) and wind resources, the capacity factor is an important parameter describing the quality of the resource. As the share of variable renewable resources (such as PV and wind) on the electric system is increasing, so does curtailment (and the fraction of time when it cannot be avoided). At high levels of renewable generation, curtailments effectively change the practical measure of resource quality from capacity factor to the incremental capacity factor. The latter accounts only for generation during hours of no curtailment and is directly connected with the marginal capital cost of renewable generators for a givenmore » level of renewable generation during the year. The Western U.S. wind generation is analyzed hourly for a system with 75% of annual generation from wind, and it is found that the value for the system of resources with equal capacity factors can vary by a factor of 2, which highlights the importance of using the incremental capacity factor instead. Finally, the effect is expected to be more pronounced in smaller geographic areas (or when transmission limitations imposed) and less pronounced at lower levels of renewable energy in the system with less curtailment.« less

  5. Wind resource quality affected by high levels of renewables

    SciTech Connect

    Diakov, Victor

    2015-06-17

    For solar photovoltaic (PV) and wind resources, the capacity factor is an important parameter describing the quality of the resource. As the share of variable renewable resources (such as PV and wind) on the electric system is increasing, so does curtailment (and the fraction of time when it cannot be avoided). At high levels of renewable generation, curtailments effectively change the practical measure of resource quality from capacity factor to the incremental capacity factor. The latter accounts only for generation during hours of no curtailment and is directly connected with the marginal capital cost of renewable generators for a given level of renewable generation during the year. The Western U.S. wind generation is analyzed hourly for a system with 75% of annual generation from wind, and it is found that the value for the system of resources with equal capacity factors can vary by a factor of 2, which highlights the importance of using the incremental capacity factor instead. Finally, the effect is expected to be more pronounced in smaller geographic areas (or when transmission limitations imposed) and less pronounced at lower levels of renewable energy in the system with less curtailment.

  6. Vestibular contributions to high-level sensorimotor functions.

    PubMed

    Medendorp, W Pieter; Selen, Luc J P

    2017-02-02

    The vestibular system, which detects motion and orientation of the head in space, is known to be important in controlling gaze to stabilize vision, to ensure postural stability and to provide our sense of self-motion. While the brain's computations underlying these functions are extensively studied, the role of the vestibular system in higher level sensorimotor functions is less clear. This review covers new research on the vestibular influence on perceptual judgments, motor decisions, and the ability to learn multiple motor actions. Guided by concepts such as optimization, inference, estimation and control, we focus on how the brain determines causal relationships between memorized and visual representations in the updating of visual space, and how vestibular, visual and efferent motor information are integrated in the estimation of body motion. We also discuss evidence that these computations involve multiple coordinate representations, some of which can be probed in parietal cortex using neuronal oscillations derived from EEG. In addition, we describe work on decision making during self-motion, showing a clear modulation of bottom-up acceleration signals on decisions in the saccadic system. Finally, we consider the importance of vestibular signals as contextual cues in motor learning and recall. Taken together, these results emphasize the impact of vestibular information on high-level sensorimotor functions, and identify future directions for theoretical, behavioral, and neurophysiological investigations.

  7. Control of high level radioactive waste-glass melters

    SciTech Connect

    Bickford, D.F.; Choi, A.S.

    1991-01-01

    Slurry Fed Melters (SFM) are being developed in the United States, Europe and Japan for the conversion of high-level radioactive waste to borosilicate glass for permanent disposal. The high transition metal, noble metal, nitrate, organic, and sulfate contents of these wastes lead to unique melter redox control requirements. Pilot waste-glass melter operations have indicated the possibility of nickel sulfide or noble-metal fission-product accumulation on melter floors, which can lead to distortion of electric heating patterns, and decrease melter life. Sulfide formation is prevented by control of the redox chemistry of the melter feed. The redox state of waste-glass melters is determined by balance between the reducing potential of organic compounds in the feed, and the oxidizing potential of gases above the melt, and nitrates and polyvalent elements in the waste. Semiquantitative models predicting limitations of organic content have been developed based on crucible testing. Computerized thermodynamic computations are being developed to predict the sequence and products of redox reactions and is assessing process variations. Continuous melter test results have been compared to improved computer staged-thermodynamic-models of redox behavior. Feed chemistry control to prevent sulfide and moderate noble metal accumulations are discussed. 17 refs., 3 figs.

  8. Potential for erosion corrosion of SRS high level waste tanks

    SciTech Connect

    Zapp, P.E.

    1994-01-01

    SRS high-level radioactive waste tanks will not experience erosion corrosion to any significant degree during slurry pump operations. Erosion corrosion in carbon steel structures at reported pump discharge velocities is dominated by electrochemical (corrosion) processes. Interruption of those processes, as by the addition of corrosion inhibitors, sharply reduces the rate of metal loss from erosion corrosion. The well-inhibited SRS waste tanks have a near-zero general corrosion rate, and therefore will be essentially immune to erosion corrosion. The experimental data on carbon steel erosion corrosion most relevant to SRS operations was obtained at the Hanford Site on simulated Purex waste. A metal loss rate of 2.4 mils per year was measured at a temperature of 102 C and a slurry velocity comparable to calculated SRS slurry velocities on ground specimens of the same carbon steel used in SRS waste tanks. Based on these data and the much lower expected temperatures, the metal loss rate of SRS tanks under waste removal and processing conditions should be insignificant, i.e. less than 1 mil per year.

  9. Metrics associated with NIH funding: a high-level view

    PubMed Central

    Jordan, Paul

    2011-01-01

    Objective To introduce the availability of grant-to-article linkage data associated with National Institutes of Health (NIH) grants and to perform a high-level analysis of the publication outputs and impacts associated with those grants. Design Articles were linked to the grants they acknowledge using the grant acknowledgment strings in PubMed using a parsing and matching process as embodied in the NIH Scientific Publication Information Retrieval & Evaluation System system. Additional data from PubMed and citation counts from Scopus were added to the linkage data. The data comprise 2 572 576 records from 1980 to 2009. Results The data show that synergies between NIH institutes are increasing over time; 29% of current articles acknowledge grants from multiple institutes. The median time lag to publication for a new grant is 3 years. Each grant contributes to approximately 1.7 articles per year, averaged over all grant types. Articles acknowledging US Public Health Service (PHS, which includes NIH) funding are cited twice as much as US-authored articles acknowledging no funding source. Articles acknowledging both PHS funding and a non-US government funding source receive on average 40% more citations that those acknowledging PHS funding sources alone. Conclusion The US PHS is effective at funding research with a higher-than-average impact. The data are amenable to further and much more detailed analysis. PMID:21527408

  10. Hemipelvectomy: high-level amputation surgery and prosthetic rehabilitation.

    PubMed

    Houdek, Matthew T; Kralovec, Michael E; Andrews, Karen L

    2014-07-01

    The hemipelvectomy, most commonly performed for pelvic tumor resection, is one of the most technically demanding and invasive surgical procedures performed today. Adequate soft tissue coverage and wound complications after hemipelvectomy are important considerations. Rehabilitation after hemipelvectomy is optimally managed by a multidisciplinary integrated team. Understanding the functional outcomes for this population assists the rehabilitation team to counsel patients, plan goals, and determine discharge needs. The most important rehabilitation goal is the optimal restoration of the patient's functional independence. Factors such as age, sex, etiology, level of amputation, and general health play important roles in determining prosthetic use. The three main criteria for successful prosthetic rehabilitation of patients with high-level amputation are comfort, function, and cosmesis. Recent advances in hip and knee joints have contributed to increased function. Prosthetic use after hemipelvectomy improves balance and decreases the need for a gait aid. Using a prosthesis helps maintain muscle strength and tone, cardiovascular health, and functional mobility. With new advances in prosthetic components, patients are choosing to use their prostheses for primary mobility.

  11. ATW system impact on high-level waste

    SciTech Connect

    Arthur, E.D.

    1992-12-01

    This report discusses the Accelerator Transmutation of Waste (ATW) concept which aims at destruction of key long-lived radionuclides in high-level nuclear waste (HLW), both fission products and actinides. This focus makes it different from most other transmutation concepts which concentrate primarily on actinide burning. The ATW system uses an accelerator-driven, sub-critical assembly to create an intense thermal neutron environment for radionuclide transmutation. This feature allows rapid transmutation under low-inventory system conditions, which in turn, has a direct impact on the size of chemical separations and materials handling components of the system. Inventories in ATW are factors of eight to thirty times smaller than reactor systems of equivalent thermal power. Chemical separations systems are relatively small in scale and can be optimized to achieve high decontamination factors and minimized waste streams. The low-inventory feature also directly impacts material amounts remaining in the system at its end of life. In addition to its low-inventory operation, the accelerator-driven neutron source features of ATW are key to providing a sufficient level of neutrons to allow transmutation of long-lived fission products.

  12. High-level fluorescence labeling of gram-positive pathogens.

    PubMed

    Aymanns, Simone; Mauerer, Stefanie; van Zandbergen, Ger; Wolz, Christiane; Spellerberg, Barbara

    2011-01-01

    Fluorescence labeling of bacterial pathogens has a broad range of interesting applications including the observation of living bacteria within host cells. We constructed a novel vector based on the E. coli streptococcal shuttle plasmid pAT28 that can propagate in numerous bacterial species from different genera. The plasmid harbors a promoterless copy of the green fluorescent variant gene egfp under the control of the CAMP-factor gene (cfb) promoter of Streptococcus agalactiae and was designated pBSU101. Upon transfer of the plasmid into streptococci, the bacteria show a distinct and easily detectable fluorescence using a standard fluorescence microscope and quantification by FACS-analysis demonstrated values that were 10-50 times increased over the respective controls. To assess the suitability of the construct for high efficiency fluorescence labeling in different gram-positive pathogens, numerous species were transformed. We successfully labeled Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus dysgalactiae subsp. equisimilis, Enterococcus faecalis, Enterococcus faecium, Streptococcus mutans, Streptococcus anginosus and Staphylococcus aureus strains utilizing the EGFP reporter plasmid pBSU101. In all of these species the presence of the cfb promoter construct resulted in high-level EGFP expression that could be further increased by growing the streptococcal and enterococcal cultures under high oxygen conditions through continuous aeration.

  13. High Level Waste Feed Certification in Hanford Double Shell Tanks

    SciTech Connect

    Thien, Micheal G.; Wells, Beric E.; Adamson, Duane J.

    2010-03-01

    The ability to effectively mix, sample, certify, and deliver consistent batches of High Level Waste (HLW) feed from the Hanford Double Shell Tanks (DST) to the Waste Treatment and Immobilization Plant (WTP) presents a significant mission risk with potential to impact mission length and the quantity of HLW glass produced. DOE’s River Protection Project (RPP) mission modeling and WTP facility modeling assume that individual 3785 cubic meter (1 million gallon) HLW feed tanks are homogenously mixed, representatively sampled, and consistently delivered to the WTP. It has been demonstrated that homogenous mixing of HLW sludge in Hanford DSTs is not likely achievable with the baseline design thereby causing representative sampling and consistent feed delivery to be more difficult. Inconsistent feed to the WTP could cause additional batch to batch operational adjustments that reduces operating efficiency and has the potential to increase the overall mission length. The Hanford mixing and sampling demonstration program will identify DST mixing performance capability, will evaluate representative sampling techniques, and will estimate feed batch consistency. An evaluation of demonstration program results will identify potential mission improvement considerations that will help ensure successful mission completion. This paper will discuss the history, progress, and future activities that will define and mitigate the mission risk.

  14. Identification of areas with high levels of untreated dental caries.

    PubMed

    Ellwood, R P; O'Mullane, D M

    1996-02-01

    In order to examine the geographical variation of dental health within 10 county districts in North Wales, 3538 children were examined. The associations between three demographic indicators, based on the 1981 OPCS census, and dental health outcomes were assessed for electoral wards within the county districts. The Townsend and Jarman indices were the first two indicators employed and the third was based on a mathematical model representing the variation in the mean number of untreated decayed surfaces per person for the wards. This model was developed using the children examined in the five most westerly county districts. Using the data derived from the five most easterly county districts, the three indicators were assessed. All three showed strong correlations (r > or = 0.88) with dental health. These results indicate that measures of dental health based on large administrative units may obscure variation within them. It is concluded that geographical methods of this type may be useful for targeting dental resources at small areas with high levels of need.

  15. Why consider subseabed disposal of high-level nuclear waste

    SciTech Connect

    Heath, G. R.; Hollister, C. D.; Anderson, D. R.; Leinen, M.

    1980-01-01

    Large areas of the deep seabed warrant assessment as potential disposal sites for high-level radioactive waste because: (1) they are far from seismically and tectonically active lithospheric plate boundaries; (2) they are far from active or young volcanos; (3) they contain thick layers of very uniform fine-grained clays; (4) they are devoid of natural resources likely to be exploited in the forseeable future; (5) the geologic and oceanographic processes governing the deposition of sediments in such areas are well understood, and are remarkably insensitive to past oceanographic and climatic changes; and (6) sedmentary records of tens of millions of years of slow, uninterrupted deposition of fine grained clay support predictions of the future stability of such sites. Data accumulated to date on the permeability, ion-retardation properties, and mechanical strength of pelagic clay sediments indicate that they can act as a primary barrier to the escape of buried nuclides. Work in progress should determine within the current decade whether subseabed disposal is environmentally acceptable and technically feasible, as well as address the legal, political and social issues raised by this new concept.

  16. Pupil responses to high-level image content.

    PubMed

    Naber, Marnix; Nakayama, Ken

    2013-05-17

    The link between arousal and pupil dilation is well studied, but it is less known that other cognitive processes can trigger pupil responses. Here we present evidence that pupil responses can be induced by high-level scene processing, independent of changes in low-level features or arousal. In Experiment 1, we recorded changes in pupil diameter of observers while they viewed a variety of natural scenes with or without a sun that were presented either upright or inverted. Image inversion had the strongest effect on the pupil responses. The pupil constricted more to the onset of upright images as compared to inverted images. Furthermore, the amplitudes of pupil constrictions to viewing images containing a sun were larger relative to control images. In Experiment 2, we presented cartoon versions of upright and inverted pictures that included either a sun or a moon. The image backgrounds were kept identical across conditions. Similar to Experiment 1, upright images triggered pupil constrictions with larger amplitudes than inverted images and images of the sun evoked greater pupil contraction than images of the moon. We suggest that the modulations of pupil responses were due to higher-level interpretations of image content.

  17. Ultrafilter Conditions for High Level Waste Sludge Processing

    SciTech Connect

    Geeting, John GH; Hallen, Richard T.; Peterson, Reid A.

    2006-08-28

    An evaluation of the optimal filtration conditions was performed based on test data obtained from filtration of a High Level Waste Sludge sample from the Hanford tank farms. This evaluation was performed using the anticipated configuration for the Waste Treatment Plant at the Hanford site. Testing was performed to identify the optimal pressure drop and cross flow velocity for filtration at both high and low solids loading. However, this analysis indicates that the actual filtration rate achieved is relatively insensitive to these conditions under anticipated operating conditions. The maximum filter flux was obtained by adjusting the system control valve pressure from 400 to 650 kPa while the filter feed concentration increased from 5 to 20 wt%. However, operating the system with a constant control valve pressure drop of 500 kPa resulted in a less than 1% reduction in the average filter flux. Also note that allowing the control valve pressure to swing as much as +/- 20% resulted in less than a 5% decrease in filter flux.

  18. High-level simulation of JWST event-driven operations

    NASA Astrophysics Data System (ADS)

    Henry, R.; Kinzel, W.

    2012-09-01

    The James Webb Space Telescope (JWST) has an event-driven architecture: an onboard Observation Plan Executive (OPE) executes an Observation Plan (OP) consisting of a sequence of observing units (visits). During normal operations, ground action to update the OP is only expected to be necessary about once a week. This architecture is designed to tolerate uncertainty in visit duration, and occasional visit failures due to inability to acquire guide stars, without creating gaps in the observing timeline. The operations concept is complicated by the need for occasional scheduling of timecritical science and engineering visits that cannot tolerate much slippage without inducing gaps, and also by onboard momentum management. A prototype Python tool called the JWST Observation Plan Execution Simulator (JOPES) has recently been developed to simulate OP execution at a high level and analyze the response of the Observatory and OPE to both nominal and contingency scenarios. Incorporating both deterministic and stochastic behavior, JOPES has potential to be a powerful tool for several purposes: requirements analysis, system verification, systems engineering studies, and test data generation. It has already been successfully applied to a study of overhead estimation bias: whether to use conservative or average-case estimates for timing components that are inherently uncertain, such as those involving guide-star acquisition. JOPES is being enhanced to support interfaces to the operational Proposal Planning Subsystem (PPS) now being developed, with the objective of "closing the loop" between testing and simulation by feeding simulated event logs back into the PPS.

  19. The GRAVITY instrument software/high-level software

    NASA Astrophysics Data System (ADS)

    Burtscher, Leonard; Wieprecht, Ekkehard; Ott, Thomas; Kok, Yitping; Yazici, Senol; Anugu, Narsireddy; Dembet, Roderick; Fedou, Pierre; Lacour, Sylvestre; Ott, Jürgen; Paumard, Thibaut; Lapeyrere, Vincent; Kervella, Pierre; Abuter, Roberto; Pozna, Eszter; Eisenhauer, Frank; Blind, Nicolas; Genzel, Reinhard; Gillessen, Stefan; Hans, Oliver; Haug, Marcus; Haussmann, Frank; Kellner, Stefan; Lippa, Magdalena; Pfuhl, Oliver; Sturm, Eckhard; Weber, Johannes; Amorim, Antonio; Brandner, Wolfgang; Rousselet-Perraut, Karine; Perrin, Guy S.; Straubmeier, Christian; Schöller, Markus

    2014-07-01

    GRAVITY is the four-beam, near-infrared, AO-assisted, fringe tracking, astrometric and imaging instrument for the Very Large Telescope Interferometer (VLTI). It is requiring the development of one of the most complex instrument software systems ever built for an ESO instrument. Apart from its many interfaces and interdependencies, one of the most challenging aspects is the overall performance and stability of this complex system. The three infrared detectors and the fast reflective memory network (RMN) recorder contribute a total data rate of up to 20 MiB/s accumulating to a maximum of 250 GiB of data per night. The detectors, the two instrument Local Control Units (LCUs) as well as the five LCUs running applications under TAC (Tools for Advanced Control) architecture, are interconnected with fast Ethernet, RMN fibers and dedicated fiber connections as well as signals for the time synchronization. Here we give a simplified overview of all subsystems of GRAVITY and their interfaces and discuss two examples of high-level applications during observations: the acquisition procedure and the gathering and merging of data to the final FITS file.

  20. The LHCb Data Acquisition and High Level Trigger Processing Architecture

    NASA Astrophysics Data System (ADS)

    Frank, M.; Gaspar, C.; Jost, B.; Neufeld, N.

    2015-12-01

    The LHCb experiment at the LHC accelerator at CERN collects collisions of particle bunches at 40 MHz. After a first level of hardware trigger with an output rate of 1 MHz, the physically interesting collisions are selected by running dedicated trigger algorithms in the High Level Trigger (HLT) computing farm. This farm consists of up to roughly 25000 CPU cores in roughly 1750 physical nodes each equipped with up to 4 TB local storage space. This work describes the LHCb online system with an emphasis on the developments implemented during the current long shutdown (LS1). We will elaborate the architecture to treble the available CPU power of the HLT farm and the technicalities to determine and verify precise calibration and alignment constants which are fed to the HLT event selection procedure. We will describe how the constants are fed into a two stage HLT event selection facility using extensively the local disk buffering capabilities on the worker nodes. With the installed disk buffers, the CPU resources can be used during periods of up to ten days without beams. These periods in the past accounted to more than 70% of the total time.

  1. Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

    SciTech Connect

    Gdowski, G.E.; Bullen, D.B. )

    1988-08-01

    Three copper-based alloys and three iron- to nickel-based austenitic alloys are being considered as possible materials for fabrication of containers for disposal of high-level radioactive waste. This waste will include spent fuel assemblies from reactors as well as high-level waste in borosilicate glass and will be sent to the prospective site at Yucca Mountain, Nevada, for disposal. The containers must maintain substantially complete containment for at least 300 yr and perhaps as long as 1000 yr. During the first 50 yr after emplacement, they must be retrievable from the disposal site. Shortly after the containers are emplaced in the repository, they will be exposed to high temperatures and high gamma radiation fields from the decay of the high-level waste. This volume surveys the available data on oxidation and corrosion of the iron- to nickel-based austenitic materials (Types 304L and 316L stainless steels and Alloy 825) and the copper-based alloy materials (CDA 102 (oxygen-free copper), CDA 613 (Cu-7Al), and CDA 715 (Cu-30Ni)), which are the present candidates for fabrication of the containers. Studies that provided a large amount of data are highlighted, and those areas in which little data exists are identified. Examples of successful applications of these materials are given. On the basis of resistance to oxidation and general corrosion, the austenitic materials are ranked as follows: Alloy 825 (best), Type 316L stainless steel, and then Type 304L stainless steel (worst). For the copper-based materials, the ranking is as follows: CDA 715 and CDA 613 (both best), and CDA 102 (worst). 110 refs., 30 figs., 13 tabs.

  2. High-level resistance to cefotaxime and ceftazidime in Klebsiella pneumoniae isolates from Cleveland, Ohio.

    PubMed Central

    Thomson, K S; Sanders, C C; Washington, J A

    1991-01-01

    Two isolates of Klebsiella pneumoniae possessing both TEM-1 and SHV-2 beta-lactamases were isolated from patients at the Cleveland Clinic in 1988. The beta-lactamases were discriminated and identified by using substrate hydrolysis data and an isoelectric focusing procedure in which the gel was overlaid with beta-lactamase inhibitors. Images PMID:1854155

  3. Identification of potato breeding clones that confer high levels of late blight resistance to their progeny

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 1996, potato seedling minitubers derived from greenhouse crosses have been grown out under heavy late blight pressure in Toluca, Mexico. A total of 2500 individuals were planted each year along with cv. Alpha as a susceptible control. Percent defoliation readings were taken on a weekly basis u...

  4. Qualification of Innovative High Level Waste Pipeline Unplugging Technologies

    SciTech Connect

    McDaniel, D.; Gokaltun, S.; Varona, J.; Awwad, A.; Roelant, D.; Srivastava, R.

    2008-07-01

    In the past, some of the pipelines have plugged during high level waste (HLW) transfers resulting in schedule delays and increased costs. Furthermore, pipeline plugging has been cited by the 'best and brightest' technical review as one of the major issues that can result in unplanned outages at the Waste Treatment Plant causing inconsistent operation. As the DOE moves toward a more active high level waste retrieval, the site engineers will be faced with increasing cross-site pipeline waste slurry transfers that will result in increased probability of a pipeline getting plugged. Hence, availability of a pipeline unplugging tool/technology is crucial to ensure smooth operation of the waste transfers and in ensuring tank farm cleanup milestones are met. FIU had earlier tested and evaluated various unplugging technologies through an industry call. Based on mockup testing, two technologies were identified that could withstand the rigors of operation in a radioactive environment and with the ability to handle sharp 90 elbows. We present results of the second phase of detailed testing and evaluation of pipeline unplugging technologies and the objective is to qualify these pipeline unplugging technologies for subsequent deployment at a DOE facility. The current phase of testing and qualification comprises of a heavily instrumented 3-inch diameter (full-scale) pipeline facilitating extensive data acquisition for design optimization and performance evaluation, as it applies to three types of plugs atypical of the DOE HLW waste. Furthermore, the data from testing at three different lengths of pipe in conjunction with the physics of the process will assist in modeling the unplugging phenomenon that will then be used to scale-up process parameters and system variables for longer and site typical pipe lengths, which can extend as much as up to 19,000 ft. Detailed information resulting from the testing will provide the DOE end-user with sufficient data and understanding of the

  5. High Levels of Molecular Chlorine found in the Arctic Atmosphere

    NASA Astrophysics Data System (ADS)

    Liao, J.; Huey, L. G.; Liu, Z.; Tanner, D.; Cantrell, C. A.; Orlando, J. J.; Flocke, F. M.; Shepson, P. B.; Weinheimer, A. J.; Hall, S. R.; Beine, H.; Wang, Y.; Ingall, E. D.; Thompson, C. R.; Hornbrook, R. S.; Apel, E. C.; Fried, A.; Mauldin, L.; Smith, J. N.; Staebler, R. M.; Neuman, J. A.; Nowak, J. B.

    2014-12-01

    Chlorine radicals are a strong atmospheric oxidant, particularly in polar regions where levels of hydroxyl radicals can be quite low. In the atmosphere, chlorine radicals expedite the degradation of methane and tropospheric ozone and the oxidation of mercury to more toxic forms. Here, we present direct measurements of molecular chlorine levels in the Arctic marine boundary layer in Barrow, Alaska, collected in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. We detected high levels of molecular chlorine of up to 400 pptv. Concentrations peaked in the early morning and late afternoon and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone are required for molecular chlorine formation. Using a time-dependent box model, we estimated that the chlorine radicals produced from the photolysis of molecular chlorine on average oxidized more methane than hydroxyl radicals and enhanced the abundance of short-lived peroxy radicals. Elevated hydroperoxyl radical levels, in turn, promoted the formation of hypobromous acid, which catalyzed mercury oxidation and the breakdown of tropospheric ozone. Therefore, we propose that molecular chlorine exerts a significant effect on the atmospheric chemistry in the Arctic. While the formation mechanisms of molecular chlorine are not yet understood, the main potential sources of chlorine include snowpack, sea salt, and sea ice. There is recent evidence of molecular halogen (Br2 and Cl2) formation in the Arctic snowpack. The coverage and composition of the snow may control halogen chemistry in the Arctic. Changes of sea ice and snow cover in the changing climate may affect air-snow-ice interaction and have a significant impact on the levels of radicals, ozone, mercury and methane in the Arctic troposphere.

  6. Engineering neural systems for high-level problem solving.

    PubMed

    Sylvester, Jared; Reggia, James

    2016-07-01

    There is a long-standing, sometimes contentious debate in AI concerning the relative merits of a symbolic, top-down approach vs. a neural, bottom-up approach to engineering intelligent machine behaviors. While neurocomputational methods excel at lower-level cognitive tasks (incremental learning for pattern classification, low-level sensorimotor control, fault tolerance and processing of noisy data, etc.), they are largely non-competitive with top-down symbolic methods for tasks involving high-level cognitive problem solving (goal-directed reasoning, metacognition, planning, etc.). Here we take a step towards addressing this limitation by developing a purely neural framework named galis. Our goal in this work is to integrate top-down (non-symbolic) control of a neural network system with more traditional bottom-up neural computations. galis is based on attractor networks that can be "programmed" with temporal sequences of hand-crafted instructions that control problem solving by gating the activity retention of, communication between, and learning done by other neural networks. We demonstrate the effectiveness of this approach by showing that it can be applied successfully to solve sequential card matching problems, using both human performance and a top-down symbolic algorithm as experimental controls. Solving this kind of problem makes use of top-down attention control and the binding together of visual features in ways that are easy for symbolic AI systems but not for neural networks to achieve. Our model can not only be instructed on how to solve card matching problems successfully, but its performance also qualitatively (and sometimes quantitatively) matches the performance of both human subjects that we had perform the same task and the top-down symbolic algorithm that we used as an experimental control. We conclude that the core principles underlying the galis framework provide a promising approach to engineering purely neurocomputational systems for problem

  7. Review of high-level waste form properties. [146 bibliographies

    SciTech Connect

    Rusin, J.M.

    1980-12-01

    This report is a review of waste form options for the immobilization of high-level-liquid wastes from the nuclear fuel cycle. This review covers the status of international research and development on waste forms as of May 1979. Although the emphasis in this report is on waste form properties, process parameters are discussed where they may affect final waste form properties. A summary table is provided listing properties of various nuclear waste form options. It is concluded that proposed waste forms have properties falling within a relatively narrow range. In regard to crystalline versus glass waste forms, the conclusion is that either glass of crystalline materials can be shown to have some advantage when a single property is considered; however, at this date no single waste form offers optimum properties over the entire range of characteristics investigated. A long-term effort has been applied to the development of glass and calcine waste forms. Several additional waste forms have enough promise to warrant continued research and development to bring their state of development up to that of glass and calcine. Synthetic minerals, the multibarrier approach with coated particles in a metal matrix, and high pressure-high temperature ceramics offer potential advantages and need further study. Although this report discusses waste form properties, the total waste management system should be considered in the final selection of a waste form option. Canister design, canister materials, overpacks, engineered barriers, and repository characteristics, as well as the waste form, affect the overall performance of a waste management system. These parameters were not considered in this comparison.

  8. High-level waste issues and resolutions document

    SciTech Connect

    Not Available

    1994-05-01

    The High-Level Waste (HLW) Issues and Resolutions Document recognizes US Department of Energy (DOE) complex-wide HLW issues and offers potential corrective actions for resolving these issues. Westinghouse Management and Operations (M&O) Contractors are effectively managing HLW for the Department of Energy at four sites: Idaho National Engineering Laboratory (INEL), Savannah River Site (SRS), West Valley Demonstration Project (WVDP), and Hanford Reservation. Each site is at varying stages of processing HLW into a more manageable form. This HLW Issues and Resolutions Document identifies five primary issues that must be resolved in order to reach the long-term objective of HLW repository disposal. As the current M&O contractor at DOE`s most difficult waste problem sites, Westinghouse recognizes that they have the responsibility to help solve some of the complexes` HLW problems in a cost effective manner by encouraging the M&Os to work together by sharing expertise, eliminating duplicate efforts, and sharing best practices. Pending an action plan, Westinghouse M&Os will take the initiative on those corrective actions identified as the responsibility of an M&O. This document captures issues important to the management of HLW. The proposed resolutions contained within this document set the framework for the M&Os and DOE work cooperatively to develop an action plan to solve some of the major complex-wide problems. Dialogue will continue between the M&Os, DOE, and other regulatory agencies to work jointly toward the goal of storing, treating, and immobilizing HLW for disposal in an environmentally sound, safe, and cost effective manner.

  9. Stability of High-Level Radioactive Waste Forms

    SciTech Connect

    Besmann, T.M.

    2001-06-22

    High-level waste (HLW) glass compositions, processing schemes, limits on waste content, and corrosion/dissolution release models are dependent on an accurate knowledge of melting temperatures and thermochemical values. Unfortunately, existing models for predicting these temperatures are empirically-based, depending on extrapolations of experimental information. In addition, present models of leaching behavior of glass waste forms use simplistic assumptions or experimentally measured values obtained under non-realistic conditions. There is thus a critical need for both more accurate and more widely applicable models for HLW glass behavior, which this project addressed. Significant progress was made in this project on modeling HLW glass. Borosilicate glass was accurately represented along with the additional important components that contain iron, lithium, potassium, magnesium, and calcium. The formation of crystalline inclusions in the glass, an issue in Hanford HLW formulations, was modeled and shown to be predictive. Thus the results of this work have already demonstrated practical benefits with the ability to map compositional regions where crystalline material forms, and therefore avoid that detrimental effect. With regard to a fundamental understanding, added insights on the behavior of the components of glass have been obtained, including the potential formation of molecular clusters. The EMSP project had very significant effects beyond the confines of Environmental Management. The models developed for glass have been used to solve a very costly problem in the corrosion of refractories for glass production. The effort resulted in another laboratory, Sandia National Laboratories-Livermore, to become conversant in the techniques and to apply those through a DOE Office of Industrial Technologies project joint with PPG Industries. The glass industry as a whole is now cognizant of these capabilities, and there is a Glass Manufacturer's Research Institute proposal

  10. PLUTONIUM/HIGH-LEVEL VITRIFIED WASTE BDBE DOSE CALCULATION

    SciTech Connect

    D.C. Richardson

    2003-03-19

    In accordance with the Nuclear Waste Policy Amendments Act of 1987, Yucca Mountain was designated as the site to be investigated as a potential repository for the disposal of high-level radioactive waste. The Yucca Mountain site is an undeveloped area located on the southwestern edge of the Nevada Test Site (NTS), about 100 miles northwest of Las Vegas. The site currently lacks rail service or an existing right-of-way. If the Yucca Mountain site is found suitable for the repository, rail service is desirable to the Office of Civilian Waste Management (OCRWM) Program because of the potential of rail transportation to reduce costs and to reduce the number of shipments relative to highway transportation. A Preliminary Rail Access Study evaluated 13 potential rail spur options. Alternative routes within the major options were also developed. Each of these options was then evaluated for potential land use conflicts and access to regional rail carriers. Three potential routes having few land use conflicts and having access to regional carriers were recommended for further investigation. Figure 1-1 shows these three routes. The Jean route is estimated to be about 120 miles long, the Carlin route to be about 365 miles long, and Caliente route to be about 365 miles long. The remaining ten routes continue to be monitored and should any of the present conflicts change, a re-evaluation of that route will be made. Complete details of the evaluation of the 13 routes can be found in the previous study. The DOE has not identified any preferred route and recognizes that the transportation issues need a full and open treatment under the National Environmental Policy Act. The issue of transportation will be included in public hearings to support development of the Environmental Impact Statement (EIS) proceedings for either the Monitored Retrievable Storage Facility or the Yucca Mountain Project or both.

  11. Radiative Lifetimes for High Levels of Neutral Fe

    NASA Astrophysics Data System (ADS)

    Lawler, James E.; Den Hartog, E.; Guzman, A.

    2013-01-01

    New radiative lifetime measurements for ~ 50 high lying levels of Fe I are reported. Laboratory astrophysics faces a challenge to provide basic spectroscopic data, especially reliable atomic transition probabilities, in the IR region for abundance studies. The availability of HgCdTe (HAWAII) detector arrays has opened IR spectral regions for extensive new spectroscopic studies. The SDSS III APOGEE project in the H-Band is an important example which will penetrate the dust obscuring the Galactic bulge. APOGEE will survey elemental abundances of 100,000 red giant stars in the bulge, bar, disk, and halo of the Milky Way. Many stellar spectra in the H-Band are, as expected, dominated by transitions of Fe I. Most of these IR transitions connect high levels of Fe. Our program has started an effort to meet this challenge with new radiative lifetime measurements on high lying levels of Fe I using time resolved laser induced fluorescence (TRLIF). The TRLIF method is typically accurate to 5% and is efficient. Our goal is to combine these accurate, absolute radiative lifetimes with emission branching fractions [1] to determine log(gf) values of the highest quality for Fe I lines in the UV, visible, and IR. This method was used very successfully by O’Brian et al. [2] on lower levels of Fe I. This method is still the best available for all but very simple spectra for which ab-initio theory is more accurate. Supported by NSF grant AST-0907732. [1] Branching fractions are being measured by M. Ruffoni and J. C. Pickering at Imperial College London. [2] O'Brian, T. R., Wickliffe, M. E., Lawler, J. E., Whaling, W., & Brault, J. W. 1991, J. Opt. Soc. Am. B 8, 1185

  12. High-level disinfection of gastrointestinal endoscope reprocessing.

    PubMed

    Chiu, King-Wah; Lu, Lung-Sheng; Chiou, Shue-Shian

    2015-02-20

    High level disinfection (HLD) of the gastrointestinal (GI) endoscope is not simply a slogan, but rather is a form of experimental monitoring-based medicine. By definition, GI endoscopy is a semicritical medical device. Hence, such medical devices require major quality assurance for disinfection. And because many of these items are temperature sensitive, low-temperature chemical methods, such as liquid chemical germicide, must be used rather than steam sterilization. In summarizing guidelines for infection prevention and control for GI endoscopy, there are three important steps that must be highlighted: manual washing, HLD with automated endoscope reprocessor, and drying. Strict adherence to current guidelines is required because compared to any other medical device, the GI endoscope is associated with more outbreaks linked to inadequate cleaning or disinfecting during HLD. Both experimental evaluation on the surveillance bacterial cultures and in-use clinical results have shown that, the monitoring of the stringent processes to prevent and control infection is an essential component of the broader strategy to ensure the delivery of safe endoscopy services, because endoscope reprocessing is a multistep procedure involving numerous factors that can interfere with its efficacy. Based on our years of experience in the surveillance of culture monitoring of endoscopic reprocessing, we aim in this study to carefully describe what details require attention in the GI endoscopy disinfection and to share our experience so that patients can be provided with high quality and safe medical practices. Quality management encompasses all aspects of pre- and post-procedural care including the efficiency of the endoscopy unit and reprocessing area, as well as the endoscopic procedure itself.

  13. Activity profile of high-level Australian lacrosse players.

    PubMed

    Polley, Chris S; Cormack, Stuart J; Gabbett, Tim J; Polglaze, Ted

    2015-01-01

    Despite lacrosse being one of the fastest growing team sports in the world, there is a paucity of information detailing the activity profile of high-level players. Microtechnology systems (global positioning systems and accelerometers) provide the opportunity to obtain detailed information on the activity profile in lacrosse. Therefore, this study aimed to analyze the activity profile of lacrosse match-play using microtechnology. Activity profile variables assessed relative to minutes of playing time included relative distance (meter per minute), distance spent standing (0-0.1 m·min), walking (0.2-1.7 m·min), jogging (1.8-3.2 m·min), running (3.3-5.6 m·min), sprinting (≥5.7 m·min), number of high, moderate, low accelerations and decelerations, and player load (PL per minute), calculated as the square root of the sum of the squared instantaneous rate of change in acceleration in 3 vectors (medio-lateral, anterior-posterior, and vertical). Activity was recorded from 14 lacrosse players over 4 matches during a national tournament. Players were separated into positions of attack, midfield, or defense. Differences (effect size [ES] ± 90% confidence interval) between positions and periods of play were considered likely positive when there was ≥75% likelihood of the difference exceeding an ES threshold of 0.2. Midfielders had likely covered higher (mean ± SD) meters per minute (100 ± 11) compared with attackers (87 ± 14; ES = 0.89 ± 1.04) and defenders (79 ± 14; ES = 1.54 ± 0.94) and more moderate and high accelerations and decelerations. Almost all variables across positions were reduced in quarter 4 compared with quarter 1. Coaches should accommodate for positional differences when preparing lacrosse players for competition.

  14. Hydrothermal transformations in an aluminophosphate glass matrix containing simulators of high-level radioactive wastes

    NASA Astrophysics Data System (ADS)

    Yudintsev, S. V.; Mal'kovsky, V. I.; Mokhov, A. V.

    2016-05-01

    The interaction of aluminophosphate glass with water at 95°C for 35 days results in glass heterogenization and in the appearance of a gel layer and various phases. The leaching rate of elements is low owing to the formation of a protective layer on the glass surface. It is shown that over 80% of uranium leached from the glass matrix occurs as colloids below 450 nm in size characterized by high migration ability in the geological environment. To determine the composition of these colloids is a primary task for further studies. Water vapor is a crystallization factor for glasses. The conditions as such may appear even at early stages of glass storage because of the failure of seals on containers of high-level radioactive wastes. The examination of water resistance of crystallized matrices and determination of the fraction of radionuclide in colloids are also subjects for further studies.

  15. Modeling the corrosion of high-level waste containers: CAM-CRM interface

    SciTech Connect

    Farmer, J.C.; Bedrossian, P.J.; McCright, R.D.

    1998-06-01

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological respository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 825, 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as A516 or Monel 400. At the present time, Alloy C-22 and A516 are favored. This publication addresses the development of models to account for corrosion of Alloy C-22 surfaces exposed directly to the Near Field Environmental (NFE), as well as to the exacerbated conditions in the CAM-CRM crevice.

  16. Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

    SciTech Connect

    Strum, M.J.; Weiss, H.; Farmer, J.C. ); Bullen, D.B. )

    1988-06-01

    This volume surveys the effects of welding on the degradation modes of three austenitic alloys: Types 304L and 316L stainless steels and Alloy 825. These materials are candidates for the fabrication of containers for the long-term storage of high-level nuclear waste. The metallurgical characteristics of fusion welds are reviewed here and related to potential degradation modes of the containers. Three specific areas are discussed in depth: (1) decreased resistance to corrosion in the forms of preferential corrosion, sensitization, and susceptibility to stress corrosion cracking, (2) hot cracking in the heat-affected zone and the weld zone, and (3) formation of intermetallic phases. The austenitic alloys are ranked as follows in terms of overall weldability: Alloy 825 (best) > Type 316L stainless steel > Type 304L stainless steel (worst). 108 refs., 31 figs., 7 tabs.

  17. Modeling the corrosion of high-level waste containers: CAM-CRM interface

    SciTech Connect

    Farmer, J. C., LLNL

    1998-06-01

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 825, 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as A516 or Monel 400. At the present time, Alloy C-22 and A516 are favored. This publication addresses the development of models to account for corrosion of Alloy C-22 surfaces exposed directly to the Near Field Environment (NFE), as well as to the exacerbated conditions in the CAM-CRM crevice.

  18. Test methods for selection of materials of construction for high-level radioactive waste vitrification. Revision

    SciTech Connect

    Bickford, D F; Corbett, R A; Morrison, W S

    1986-01-01

    Candidate materials of construction were evaluated for a facility at the Department of Energy's Savannah River Plant to vitrify high-level radioactive waste. Limited operating experience was available under the corrosive conditions of the complex vitrification process. The objective of the testing program was to provide a high degree of assurance that equipment will meet or exceed design lifetimes. To meet this objective in reasonable time and minimum cost, a program was designed consisting of a combination of coupon immersion and electrochemical laboratory tests and pilot-scale tests. Stainless steels and nickel-based alloys were tested. Alloys that were most resistant to general and local attack contained nickel, molybdenum (>9%), and chromium (where Cr + Mo > 30%). Alloy C-276 was selected as the reference material for process equipment. Stellite 6 was selected for abrasive service in the presence of formic acid. Alloy 690 and ALLCORR were selected for specific applications.

  19. Incorporation of simulated high-level nuclear waste in gel spheres

    SciTech Connect

    Arnold, W.D.; Bond, W.D.; Robinson, S.M.

    1982-12-01

    Gel sphere technology developed for reactor fuel fabrication was applied to the fixation of simulated high-level radioactive waste in crystalline ceramic form for permanent disposal. Gel spheres containing simulated alkaline defense waste sludges and ceramic matrix materials were prepared by internal gelation at waste loadings as high as 90%. The gel spheres were amenable to subsequent drying, sintering, and coating procedures to produce crystalline waste forms with extremely high leach resistances. Potential application of this technique to the processing of commercial power reactor waste was demonstrated by incorporating simulated Purex solvent extraction waste in gel spheres with up to 20% waste loading. Cesium present in the simulated waste was adsorbed on zeolite and immobilized by coating with carbon.

  20. Development and testing of SYNROC for high level radioactive waste fixation

    SciTech Connect

    Reeve, K.D.; Levins, D.M.; Ramm, E.J.; Woolfrey, J.L.; Buykx, W.J.; Ryan, R.K.; Chapman, J.F.

    1981-01-01

    Research and development on the SYNROC concept for high level radioactive waste fixation commenced at the Australian Atomic Energy Commission Research Establishment, Lucas Heights, in March 1979, in collaboration with a complementary program at The Australian National University (ANU). The present paper reports progress in the project's second year and reviews its current status. An inactive 30 kg-scale SYNROC fabrication line incorporating in-can hot pressing as the fabrication step has been built for operation in mid-1981. Atmospheric pressure and hydrothermal leach tests are demonstrating the excellent leach resistance of SYNROC. Accelerated radiation damage tests using fast neutrons are simulating damage in SYNROC for periods of close to 10/sup 6/ years. In supporting research, mineral phase development, impact friability and thermophysical properties of SYNROC are being studied. 21 refs.

  1. Task alters category representations in prefrontal but not high-level visual cortex.

    PubMed

    Bugatus, Lior; Weiner, Kevin S; Grill-Spector, Kalanit

    2017-04-04

    A central question in neuroscience is how cognitive tasks affect category representations across the human brain. Regions in lateral occipito-temporal cortex (LOTC), ventral temporal cortex (VTC), and ventro-lateral prefrontal cortex (VLFPC) constitute the extended "what" pathway, which is considered instrumental for visual category processing. However, it is unknown (1) whether distributed responses across LOTC, VTC, and VLPC explicitly represent category, task, or some combination of both, and (2) in what way representations across these subdivisions of the extended 'what' pathway may differ. To fill these gaps in knowledge, we scanned 12 participants using fMRI to test the effect of category and task on distributed responses across LOTC, VTC, and VLPFC. Results reveal that task and category modulate responses in both high-level visual regions, as well as prefrontal cortex. However, we found fundamentally different types of representations across the brain. Distributed responses in high-level visual regions are more strongly driven by category than task, and exhibit task-independent category representations. In contrast, distributed responses in prefrontal cortex are more strongly driven by task than category, and contain task-dependent category representations. Together, these findings of differential representations across the brain support a new idea that LOTC and VTC maintain stable and separable category representations allowing efficient processing of visual information, while prefrontal cortex contains flexible representations in which separable category information may emerge only when relevant to the task.

  2. Development of Concentration and Calcination Technology For High Level Liquid Waste

    SciTech Connect

    Pande, D.P.

    2006-07-01

    The concentrated medium and high-level liquid radio chemicals effluents contain nitric acid, water along with the dissolved chemicals including the nitrates of the radio nuclides. High level liquid waste contain mainly nitrates of cesium, strontium, cerium, zirconium, chromium, barium, calcium, cobalt, copper, pickle, iron etc. and other fission products. This concentrated solution requires further evaporation, dehydration, drying and decomposition in temperature range of 150 to 700 deg. C. The addition of the calcined solids in vitrification pot, instead of liquid feed, helps to avoid low temperature zone because the vaporization of the liquid and decomposition of nitrates do not take place inside the melter. In our work Differential and thermo gravimetric studies has been carried out in the various stages of thermal treatment including drying, dehydration and conversion to oxide forms. Experimental studies were done to characterize the chemicals present in high-level radioactive waste. A Rotary Ball Kiln Calciner was used for development of the process because this is amenable for continuous operation and moderately good heat transfer can be achieved inside the kiln. This also has minimum secondary waste and off gases generation. The Rotary Ball Kiln Calciner Demonstration facility system was designed and installed for the demonstration of calcination process. The Rotary Ball Kiln Calciner is a slowly rotating slightly inclined horizontal tube that is externally heated by means of electric resistance heating. The liquid feed is sprayed onto the moving bed of metal balls in a slowly rotating calciner by a peristaltic type-metering pump. The vaporization of the liquid occurs in the pre-calcination zone due to counter current flow of hot gases. The dehydration and denitration of the solids occurs in the calcination zone, which is externally heated by electrical furnace. The calcined powder is cooled in the post calcination portion. It has been demonstrated that the

  3. JET MIXING ANALYSIS FOR SRS HIGH-LEVEL WASTE RECOVERY

    SciTech Connect

    Lee, S.

    2011-07-05

    The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank to ensure uniformity of the discharge stream. Mixing is accomplished with one to four slurry pumps located within the tank liquid. The slurry pump may be fixed in position or they may rotate depending on the specific mixing requirements. The high-level waste in Tank 48 contains insoluble solids in the form of potassium tetraphenyl borate compounds (KTPB), monosodium titanate (MST), and sludge. Tank 48 is equipped with 4 slurry pumps, which are intended to suspend the insoluble solids prior to transfer of the waste to the Fluidized Bed Steam Reformer (FBSR) process. The FBSR process is being designed for a normal feed of 3.05 wt% insoluble solids. A chemical characterization study has shown the insoluble solids concentration is approximately 3.05 wt% when well-mixed. The project is requesting a Computational Fluid Dynamics (CFD) mixing study from SRNL to determine the solids behavior with 2, 3, and 4 slurry pumps in operation and an estimate of the insoluble solids concentration at the suction of the transfer pump to the FBSR process. The impact of cooling coils is not considered in the current work. The work consists of two principal objectives by taking a CFD approach: (1) To estimate insoluble solids concentration transferred from Tank 48 to the Waste Feed Tank in the FBSR process and (2) To assess the impact of different combinations of four slurry pumps on insoluble solids suspension and mixing in Tank 48. For this work, several different combinations of a maximum of four pumps are considered to determine the resulting flow patterns and local flow velocities which are thought to be associated with sludge particle mixing. Two different elevations of pump nozzles are used for an assessment of the flow patterns on the tank mixing. Pump design and operating parameters used for the analysis are summarized in Table 1. The baseline

  4. Phylogeographic reconstruction of a bacterial species with high levels of lateral gene transfer

    USGS Publications Warehouse

    Pearson, T.; Giffard, P.; Beckstrom-Sternberg, S.; Auerbach, R.; Hornstra, H.; Tuanyok, A.; Price, E.P.; Glass, M.B.; Leadem, B.; Beckstrom-Sternberg, J. S.; Allan, G.J.; Foster, J.T.; Wagner, D.M.; Okinaka, R.T.; Sim, S.H.; Pearson, O.; Wu, Z.; Chang, J.; Kaul, R.; Hoffmaster, A.R.; Brettin, T.S.; Robison, R.A.; Mayo, M.; Gee, J.E.; Tan, P.; Currie, B.J.; Keim, P.

    2009-01-01

    Background: Phylogeographic reconstruction of some bacterial populations is hindered by low diversity coupled with high levels of lateral gene transfer. A comparison of recombination levels and diversity at seven housekeeping genes for eleven bacterial species, most of which are commonly cited as having high levels of lateral gene transfer shows that the relative contributions of homologous recombination versus mutation for Burkholderia pseudomallei is over two times higher than for Streptococcus pneumoniae and is thus the highest value yet reported in bacteria. Despite the potential for homologous recombination to increase diversity, B. pseudomallei exhibits a relative lack of diversity at these loci. In these situations, whole genome genotyping of orthologous shared single nucleotide polymorphism loci, discovered using next generation sequencing technologies, can provide very large data sets capable of estimating core phylogenetic relationships. We compared and searched 43 whole genome sequences of B. pseudomallei and its closest relatives for single nucleotide polymorphisms in orthologous shared regions to use in phylogenetic reconstruction. Results: Bayesian phylogenetic analyses of >14,000 single nucleotide polymorphisms yielded completely resolved trees for these 43 strains with high levels of statistical support. These results enable a better understanding of a separate analysis of population differentiation among >1,700 B. pseudomallei isolates as defined by sequence data from seven housekeeping genes. We analyzed this larger data set for population structure and allele sharing that can be attributed to lateral gene transfer. Our results suggest that despite an almost panmictic population, we can detect two distinct populations of B. pseudomallei that conform to biogeographic patterns found in many plant and animal species. That is, separation along Wallace's Line, a biogeographic boundary between Southeast Asia and Australia. Conclusion: We describe an

  5. Phylogeographic reconstruction of a bacterial species with high levels of lateral gene transfer

    PubMed Central

    2009-01-01

    Background Phylogeographic reconstruction of some bacterial populations is hindered by low diversity coupled with high levels of lateral gene transfer. A comparison of recombination levels and diversity at seven housekeeping genes for eleven bacterial species, most of which are commonly cited as having high levels of lateral gene transfer shows that the relative contributions of homologous recombination versus mutation for Burkholderia pseudomallei is over two times higher than for Streptococcus pneumoniae and is thus the highest value yet reported in bacteria. Despite the potential for homologous recombination to increase diversity, B. pseudomallei exhibits a relative lack of diversity at these loci. In these situations, whole genome genotyping of orthologous shared single nucleotide polymorphism loci, discovered using next generation sequencing technologies, can provide very large data sets capable of estimating core phylogenetic relationships. We compared and searched 43 whole genome sequences of B. pseudomallei and its closest relatives for single nucleotide polymorphisms in orthologous shared regions to use in phylogenetic reconstruction. Results Bayesian phylogenetic analyses of >14,000 single nucleotide polymorphisms yielded completely resolved trees for these 43 strains with high levels of statistical support. These results enable a better understanding of a separate analysis of population differentiation among >1,700 B. pseudomallei isolates as defined by sequence data from seven housekeeping genes. We analyzed this larger data set for population structure and allele sharing that can be attributed to lateral gene transfer. Our results suggest that despite an almost panmictic population, we can detect two distinct populations of B. pseudomallei that conform to biogeographic patterns found in many plant and animal species. That is, separation along Wallace's Line, a biogeographic boundary between Southeast Asia and Australia. Conclusion We describe an

  6. Cementitious Grout for Closing SRS High Level Waste Tanks - 12315

    SciTech Connect

    Langton, C.A.; Stefanko, D.B.; Burns, H.H.; Waymer, J.; Mhyre, W.B.; Herbert, J.E.; Jolly, J.C. Jr.

    2012-07-01

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. Ancillary equipment abandoned in the tanks will also be filled to the extent practical. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and to be chemically reducing with a reduction potential (Eh) of -200 to -400. Grouts with this chemistry stabilize potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted to support the mass placement strategy developed by

  7. Advanced High-Level Waste Glass Research and Development Plan

    SciTech Connect

    Peeler, David K.; Vienna, John D.; Schweiger, Michael J.; Fox, Kevin M.

    2015-07-01

    The U.S. Department of Energy Office of River Protection (ORP) has implemented an integrated program to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. The integrated ORP program is focused on providing a technical, science-based foundation from which key decisions can be made regarding the successful operation of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) facilities. The fundamental data stemming from this program will support development of advanced glass formulations, key process control models, and tactical processing strategies to ensure safe and successful operations for both the low-activity waste (LAW) and high-level waste (HLW) vitrification facilities with an appreciation toward reducing overall mission life. The purpose of this advanced HLW glass research and development plan is to identify the near-, mid-, and longer-term research and development activities required to develop and validate advanced HLW glasses and their associated models to support facility operations at WTP, including both direct feed and full pretreatment flowsheets. This plan also integrates technical support of facility operations and waste qualification activities to show the interdependence of these activities with the advanced waste glass (AWG) program to support the full WTP mission. Figure ES-1 shows these key ORP programmatic activities and their interfaces with both WTP facility operations and qualification needs. The plan is a living document that will be updated to reflect key advancements and mission strategy changes. The research outlined here is motivated by the potential for substantial economic benefits (e.g., significant increases in waste throughput and reductions in glass volumes) that will be realized when advancements in glass formulation continue and models supporting facility operations are implemented. Developing and applying advanced

  8. Development of Crystal-Tolerant High-Level Waste Glasses

    SciTech Connect

    Matyas, Josef; Vienna, John D.; Schaible, Micah J.; Rodriguez, Carmen P.; Crum, Jarrod V.; Arrigoni, Alyssa L.; Tate, Rachel M.

    2010-12-17

    Twenty five glasses were formulated. They were batched from HLW AZ-101 simulant or raw chemicals and melted and tested with a series of tests to elucidate the effect of spinel-forming components (Ni, Fe, Cr, Mn, and Zn), Al, and noble metals (Rh2O3 and RuO2) on the accumulation rate of spinel crystals in the glass discharge riser of the high-level waste (HLW) melter. In addition, the processing properties of glasses, such as the viscosity and TL, were measured as a function of temperature and composition. Furthermore, the settling of spinel crystals in transparent low-viscosity fluids was studied at room temperature to access the shape factor and hindered settling coefficient of spinel crystals in the Stokes equation. The experimental results suggest that Ni is the most troublesome component of all the studied spinel-forming components producing settling layers of up to 10.5 mm in just 20 days in Ni-rich glasses if noble metals or a higher concentration of Fe was not introduced in the glass. The layer of this thickness can potentially plug the bottom of the riser, preventing glass from being discharged from the melter. The noble metals, Fe, and Al were the components that significantly slowed down or stopped the accumulation of spinel at the bottom. Particles of Rh2O3 and RuO2, hematite and nepheline, acted as nucleation sites significantly increasing the number of crystals and therefore decreasing the average crystal size. The settling rate of ≤10-μm crystal size around the settling velocity of crystals was too low to produce thick layers. The experimental data for the thickness of settled layers in the glasses prepared from AZ-101 simulant were used to build a linear empirical model that can predict crystal accumulation in the riser of the melter as a function of concentration of spinel-forming components in glass. The developed model predicts the thicknesses of accumulated layers quite well, R2 = 0.985, and can be become an efficient tool for the formulation

  9. Anticipated Degradation Modes of Metallic Engineered Barriers for High-Level Nuclear Waste Repositories

    NASA Astrophysics Data System (ADS)

    Rodríguez, Martín A.

    2014-03-01

    Metallic engineered barriers must provide a period of absolute containment to high-level radioactive waste in geological repositories. Candidate materials include copper alloys, carbon steels, stainless steels, nickel alloys, and titanium alloys. The national programs of nuclear waste management have to identify and assess the anticipated degradation modes of the selected materials in the corresponding repository environment, which evolves in time. Commonly assessed degradation modes include general corrosion, localized corrosion, stress-corrosion cracking, hydrogen-assisted cracking, and microbiologically influenced corrosion. Laboratory testing and modeling in metallurgical and environmental conditions of similar and higher aggressiveness than those expected in service conditions are used to evaluate the corrosion resistance of the materials. This review focuses on the anticipated degradation modes of the selected or reference materials as corrosion-resistant barriers in nuclear repositories. These degradation modes depend not only on the selected alloy but also on the near-field environment. The evolution of the near-field environment varies for saturated and unsaturated repositories considering backfilled and unbackfilled conditions. In saturated repositories, localized corrosion and stress-corrosion cracking may occur in the initial aerobic stage, while general corrosion and hydrogen-assisted cracking are the main degradation modes in the anaerobic stage. Unsaturated repositories would provide an oxidizing environment during the entire repository lifetime. Microbiologically influenced corrosion may be avoided or minimized by selecting an appropriate backfill material. Radiation effects are negligible provided that a thick-walled container or an inner shielding container is used.

  10. Corrosion issues in high-level nuclear waste containers

    NASA Astrophysics Data System (ADS)

    Asl, Samin Sharifi

    In this dissertation different aspects of corrosion and electrochemistry of copper, candidate canister material in Scandinavian high-level nuclear waste disposal program, including the thermodynamics and kinetics of the reactions that are predicted to occur in the practical system have been studied. A comprehensive thermodynamic study of copper in contact with granitic groundwater of the type and composition that is expected in the Forsmark repository in Sweden has been performed. Our primary objective was to ascertain whether copper would exist in the thermodynamically immune state in the repository, in which case corrosion could not occur and the issue of corrosion in the assessment of the storage technology would be moot. In spite of the fact that metallic copper has been found to exist for geological times in granitic geological formations, copper is well-known to be activated from the immune state to corrode by specific species that may exist in the environment. The principal activator of copper is known to be sulfur in its various forms, including sulfide (H2S, HS-, S2-), polysulfide (H2Sx, HSx -, Sx 2-), poly sulfur thiosulfate ( SxO3 2-), and polythionates (SxO6 2-). A comprehensive study of this aspect of copper chemistry has never been reported, and yet an understanding of this issue is vital for assessing whether copper is a suitable material for fabricating canisters for the disposal of HLNW. Our study identifies and explores those species that activate copper; these species include sulfur-containing entities as well as other, non-sulfur species that may be present in the repository. The effects of temperature, solution pH, and hydrogen pressure on the kinetics of the hydrogen electrode reaction (HER) on copper in borate buffer solution have been studied by means of steady-state polarization measurements, including electrochemical impedance spectroscopy (EIS). In order to obtain electrokinetic parameters, such as the exchange current density and the

  11. Cost evaluation of a DSN high level real-time language

    NASA Technical Reports Server (NTRS)

    Mckenzie, M.

    1977-01-01

    The hypothesis that the implementation of a DSN High Level Real Time Language will reduce real time software expenditures is explored. The High Level Real Time Language is found to be both affordable and cost-effective.

  12. High-level waste program progress report, April 1, 1980-June 30, 1980

    SciTech Connect

    1980-08-01

    The highlights of this report are on: waste management analysis for nuclear fuel cycles; fixation of waste in concrete; study of ceramic and cermet waste forms; alternative high-level waste forms development; and high-level waste container development.

  13. Contribution of rpoB Mutations to Development of Rifamycin Cross-Resistance in Mycobacterium tuberculosis

    PubMed Central

    Williams, D. L.; Spring, L.; Collins, L.; Miller, L. P.; Heifets, L. B.; Gangadharam, P. R. J.; Gillis, T. P.

    1998-01-01

    The contributions of 23 insertion, deletion, or missense mutations within an 81-bp fragment of rpoB, the gene encoding the β-subunit of the DNA-dependent RNA polymerase of Mycobacterium tuberculosis, to the development of resistance to rifamycins (rifampin, rifabutin, rifapentine, and KRM-1648) in 29 rifampin-resistant clinical isolates were defined. Specific mutant rpoB alleles led to the development of cross-resistance to all rifamycins tested, while a subset of mutations were associated with resistance to rifampin and rifapentine but not to KRM-1648 or rifabutin. To further study the impact of specific rpoB mutant alleles on the development of rifamycin resistance, mutations were incorporated into the rpoB gene of M. tuberculosis H37Rv, contained on a mycobacterial shuttle plasmid, by in vitro mutagenesis. Recombinant M. tuberculosis clones containing plasmids with specific mutations in either codon 531 or 526 of rpoB exhibited high-level resistance to all rifamycins tested, whereas clones containing a plasmid with a mutation in codon 516 exhibited high-level resistance to rifampin and rifapentine but were susceptible to both rifabutin and KRM-1648. These results provided additional proof of the association of specific rpoB mutations with the development of rifamycin resistance and corroborate previous reports of the usefulness of rpoB genotyping for predicting rifamycin-resistant phenotypes. PMID:9661035

  14. International program to study subseabed disposal of high-level radioactive wastes

    SciTech Connect

    Carlin, E.M.; Hinga, K.R.; Knauss, J.A.

    1984-01-01

    This report provides an overview of the international program to study seabed disposal of nuclear wastes. Its purpose is to inform legislators, other policy makers, and the general public as to the history of the program, technological requirements necessary for feasibility assessment, legal questions involved, international coordination of research, national policies, and research and development activities. Each of these major aspects of the program is presented in a separate section. The objective of seabed burial, similar to its continental counterparts, is to contain and to isolate the wastes. The subseabed option should not be confuesed with past practices of ocean dumping which have introduced wastes into ocean waters. Seabed disposal refers to the emplacement of solidified high-level radioactive waste (with or without reprocessing) in certain geologically stable sediments of the deep ocean floor. Specially designed surface ships would transport waste canisters from a port facility to the disposal site. Canisters would be buried from a few tens to a few hundreds of meters below the surface of ocean bottom sediments, and hence would not be in contact with the overlying ocean water. The concept is a multi-barrier approach for disposal. Barriers, including waste form, canister, ad deep ocean sediments, will separate wastes from the ocean environment. High-level wastes (HLW) would be stabilized by conversion into a leach-resistant solid form such as glass. This solid would be placed inside a metallic canister or other type of package which represents a second barrier. The deep ocean sediments, a third barrier, are discussed in the Feasibility Assessment section. The waste form and canister would provide a barrier for several hundred years, and the sediments would be relied upon as a barrier for thousands of years. 62 references, 3 figures, 2 tables.

  15. Interspecific hybridization between the cultivated potato Solanum tuberosum subspecies tuberosum L. and the wild species S. circaeifolium subsp. circaeifolium Bitter exhibiting resistance to Phytophthora infestans (Mont.) de Bary and Globodera pallida (Stone) Behrens : 2. Sexual hybrids.

    PubMed

    Louwes, K M; Hoekstra, R; Mattheij, W M

    1992-07-01

    Crossability between the diploid species S. circaeifolium subsp. circaeifolium (crc) and other diploid species, primarily diploid S. tuberosum subsp. tuberosum (tbr-2x), was studied. Forty-seven hybrids were obtained from crosses between crc as female parent and tbr-2x and some other species from series Tuberosa as male parents. Of these hybrids 17% were diploids; the other 83% were triploids, probably carrying two genomes of crc. Female fertility was sufficient to obtain offspring from backcrosses with the cultivated parent. Pollen stainability of the f1 varied, and micro-pollen as well as unreduced pollen occurred. During meiosis of the diploids and triploids a rather high proportion of univalents was found, and in the triploids on average two or three trivalents per cell were found. All hybrids were resistant to Globodera pallida pathotypes 2 and 3, and 75% of the tested genotypes were highly resistant to Phytophthora infestans. Solanidine, tomatidine, tomatidenol, and demissidine glycosides were found in tubers of the hybrids. Comparisons with somatic hybrids between crc and tbr-2x are made. It is concluded that crc is a valuable Solanum species that can and should be included in potato breeding programs.

  16. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  17. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  18. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  19. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  20. 21 CFR 880.6885 - Liquid chemical sterilants/high level disinfectants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Liquid chemical sterilants/high level... and Personal Use Miscellaneous Devices § 880.6885 Liquid chemical sterilants/high level disinfectants. (a) Identification. A liquid chemical sterilant/high level disinfectant is a germicide that...

  1. 40 CFR 1065.725 - High-level ethanol-gasoline blends.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false High-level ethanol-gasoline blends... Calibration Standards § 1065.725 High-level ethanol-gasoline blends. For testing vehicles capable of operating on a high-level ethanol-gasoline blend, create a test fuel as follows: (a) Add ethanol to an E10...

  2. Mechanisms of resistance to paraquat in plants.

    PubMed

    Hawkes, Timothy R

    2014-09-01

    The aim of this brief review is to draw information from studies of the mechanism of evolved resistance in weeds, together with information from laboratory studies of paraquat tolerance in model plants. Plants having mutations that limit paraquat uptake into cytoplasm, that confer various stress tolerances or that have transgenes that co-express two or more of the chloroplast Halliwell-Asada cycle enzymes can all exhibit enhanced tolerance to paraquat. However, none of these mechanisms correspond to the high-level resistances that have evolved naturally in weeds. Most, but not all, of the evidence from studies of paraquat-resistant biotypes of weeds can reasonably be reconciled with the proposal of a single major gene mechanism that sequesters paraquat away from chloroplasts and into the vacuole. However, the molecular details of this putative mechanism remain ill-defined.

  3. Traveling Exhibitions: translating current science into effective science exhibitions

    NASA Astrophysics Data System (ADS)

    Dusenbery, P.; Morrow, C.; Harold, J.

    The Space Science Institute (SSI) of Boulder, Colorado has recently developed two museum exhibits called the Space Weather Center and MarsQuest. It is currently planning to develop two other exhibitions called Cosmic Origins and InterActive Earth. Museum exhibitions provide research scientists the opportunity to engage in a number of activities that are vital to the success of earth and space outreach programs. The Space Weather Center was developed in partnership with various research missions at NASA's Goddard Space Flight Center. The focus of the presentation will be on the Institute's MarsQuest exhibition. This project is a 5000 square-foot, 2.5M, traveling exhibition that is now touring the country. The exhibit's 3-year tour is enabling millions of Americans to share in the excitement of the scientific exploration of Mars and learn more about their own planet in the process. The associated planetarium show and education program will also be described, with particular emphasis on workshops to orient host museum staff (e.g. museum educators and docents). The workshops make innovative connections between the exhibitions interactive experiences and lesson plans aligned with the National Science Education Standards. SSI is also developing an interactive web site called MarsQuest On-line. The linkage between the web site, education program and exhibit will be discussed. MarsQuest and SSI's other exhibitions are good models for actively involving scientists and their discoveries to help improve informal science education in the museum community and for forging a stronger connection between formal and informal education.

  4. Effect of Tulathromycin on Colonization Resistance, Antimicrobial Resistance, and Virulence of Human Gut Microbiota in Chemostats

    PubMed Central

    Hao, Haihong; Zhou, Shengxi; Cheng, Guyue; Dai, Menghong; Wang, Xu; Liu, Zhenli; Wang, Yulian; Yuan, Zonghui

    2016-01-01

    To evaluate microbiological safety of tulathromycin on human intestinal bacteria, tulathromycin (0, 0.1, 1, 10, and 100 μg/mL) was added into Chemostats. Before and after drug exposure, we monitored (1) population, SCFA products, antimicrobial resistance, and colonization resistance of gut microbiota, and (2) the antimicrobial resistance genes, transferability, virulent genes, pathogenicity of Enterococus faecalis. Results showed that low level of tulathromycin did not exhibit microbiological hazard on resistance selection and colonization resistance. However, high level of tulathromycin (10 and 100 μg/mL) may disturb colonization resistance of human gut microbiota and select antimicrobial resistant E. faecalis. Most of the selected resistant E. faecalis carried resistant gene of ermB, transferable element of Tn1545 and three virulence genes (esp, cylA, and ace). One of them (E. faecalis 143) was confirmed to have higher horizontal transfer risk and higher pathogenicity. The calculated no observable adverse effect concentration (NOAEC) and microbiological acceptable daily intake (mADI) in our study was 1 μg/mL and 14.66 μg/kg.bw/day, respectively. PMID:27092131

  5. Development of integraded mechanistically-based degradation-mode models for performance assessment of high-level waste containers

    SciTech Connect

    Farmer, J. C., LLNL

    1998-06-01

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-tayer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 825, 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as A516 Gr 55 or Monel 400. At the present time, Alloy C- 22 and A516 Gr 55 are favored.

  6. Development of integrated mechanistically-based degradation-mode models for performance assessment of high-level waste containers

    SciTech Connect

    Bedrossian, P; Estill, J; Farmer, J; Hopper, R; Horn, J; Huang, J S; McCright, D; Roy, A; Wang, F; Wilfinger, K

    1999-02-08

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 825, 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as A516 Gr 55, a carbon steel, or Monel 400. At the present time, Alloy C-22 and A516 G4 55 are favored.

  7. MODELING THE CORROSION OF HIGH-LEVEL WASTE CONTAINERS CAM-CRM INTERFACE

    SciTech Connect

    Farmer, Joseph; McCright, Daniel

    1998-06-01

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as carbon steel or Monel400. Initially, the containers will be hot and dry due to the heat generated by radioactive decay. However, the temperature will eventually drop to levels where both humid air and aqueous phase corrosion will be possible. As the outer barrier is penetrated, uniform corrosion of the CRM will be possible in exfoliated areas. The possibility for crevice formation between the CAM and CRM will also exist. In the case of either Alloy 625 or C-22, a crevice will have to form before significant penetration of the CRM can occur. Crevice corrosion of the CRMs has been well documented. Lillard and Scully have induced crevice corrosion in Alloy 625 during exposure to artificial sea water. Jones and Wilde have prepared simulated crevice solutions of FeCl{sub 2}, NiCl{sub 2} and CrCl{sub 3}, and measured substantial pH suppression. Asphahani measured the dissolution rates of Alloys 625 and C-22 in such artificial crevice solutions at various temperatures. Others have observed no significant localized attack in less severe environments.

  8. Modeling the corrosion of high-level waste containers CAM-CRM interface

    SciTech Connect

    Farmer, J.C.; McCright, M.

    1997-12-09

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design,the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 625 and C-22, while the outer barrier is made of a corrosion allowance material (CAM) such as carbon steel or Monel 400. Initially, the containers will be hot and dry due to the heat generated by radioactive decay. However, the temperature will eventually drop to levels where both humid air and aqueous phase corrosion will be possible. As the outer barrier is penetrated, uniform corrosion of the CRM will be possible of exfoliated areas. The possibility of crevice formation between the CAM and CRM will also exist. In the case of either Alloy 625 or C-22, a crevice will have to form before significant penetration of the CRM can occur. Crevice corrosion of the CRMs has been well documented.

  9. Modeling of Boehmite Leaching from Actual Hanford High-Level Waste Samples

    SciTech Connect

    Snow, L.A.; Rapko, B.M.; Poloski, A.P.; Peterson, R.A.

    2007-07-01

    The U.S. Department of Energy plans to vitrify approximately 60,000 metric tons of high-level waste (HLW) sludge from underground storage tanks at the Hanford Site in Southwest Washington State. To reduce the volume of HLW requiring treatment, a goal has been set to remove a significant quantity of the aluminum, which comprises nearly 70 percent of the sludge. Aluminum is found in the form of gibbsite and sodium aluminate, which can be easily dissolved by washing the waste stream with caustic, and boehmite, which comprises nearly half of the total aluminum, but is more resistant to caustic dissolution and requires higher treatment temperatures and hydroxide concentrations. Chromium, which makes up a much smaller amount ({approx}3%) of the sludge, must also be removed because there is a low tolerance for chromium in the HLW immobilization process. In this work, the coupled dissolution kinetics of aluminum and chromium species during caustic leaching of actual Hanford HLW samples is examined. The experimental results are used to develop a model that provides a basis for predicting dissolution dynamics from known process temperature and hydroxide concentration. (authors)

  10. Modeling the corrosion of high-level waste containers: CAM-CRM interface

    SciTech Connect

    Bedrossian, P J; Farmer, J C; McCright, R D

    1998-06-01

    A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 825, 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as A5 16 or Monel 400. At the present time, Alloy C-22 and A516 are favored. This publication addresses the development of models to account for corrosion of Alloy C-22 surfaces exposed directly to the Near Field Environment (NFE), as well as to the exacerbated conditions in the CAM-CRM crevice. [5]. Haynes International has published corrosion rates of Alloys 625 and C-22 in artificial crevice solutions (5-10 wt. % FeCl,) at various temperatures (25, 50 and 75 C) [6,7]. In this case, the observed rates for Alloy C-22 appear to be due to passive dissolution. It is believed that Alloy C-22 must be at an electrochemical potential above the repassivation potential to initiate localized corrosion.

  11. Nitrogen Addition Significantly Affects Forest Litter Decomposition under High Levels of Ambient Nitrogen Deposition

    PubMed Central

    Chen, Gang; Peng, Yong; Xiao, Yin-long; Hu, Ting-xing; Zhang, Jian; Li, Xian-wei; Liu, Li; Tang, Yi

    2014-01-01

    Background Forest litter decomposition is a major component of the global carbon (C) budget, and is greatly affected by the atmospheric nitrogen (N) deposition observed globally. However, the effects of N addition on forest litter decomposition, in ecosystems receiving increasingly higher levels of ambient N deposition, are poorly understood. Methodology/Principal Findings We conducted a two-year field experiment in five forests along the western edge of the Sichuan Basin in China, where atmospheric N deposition was up to 82–114 kg N ha–1 in the study sites. Four levels of N treatments were applied: (1) control (no N added), (2) low-N (50 kg N ha–1 year–1), (3) medium-N (150 kg N ha–1 year–1), and (4) high-N (300 kg N ha–1 year–1), N additions ranging from 40% to 370% of ambient N deposition. The decomposition processes of ten types of forest litters were then studied. Nitrogen additions significantly decreased the decomposition rates of six types of forest litters. N additions decreased forest litter decomposition, and the mass of residual litter was closely correlated to residual lignin during the decomposition process over the study period. The inhibitory effect of N addition on litter decomposition can be primarily explained by the inhibition of lignin decomposition by exogenous inorganic N. The overall decomposition rate of ten investigated substrates exhibited a significant negative linear relationship with initial tissue C/N and lignin/N, and significant positive relationships with initial tissue K and N concentrations; these relationships exhibited linear and logarithmic curves, respectively. Conclusions/Significance This study suggests that the expected progressive increases in N deposition may have a potential important impact on forest litter decomposition in the study area in the presence of high levels of ambient N deposition. PMID:24551152

  12. Population genetic structure of a centipede species with high levels of developmental instability.

    PubMed

    Fusco, Giuseppe; Leśniewska, Małgorzata; Congiu, Leonardo; Bertorelle, Giorgio

    2015-01-01

    European populations of the geophilomorph centipede Haplophilus subterraneus show a high proportion of individuals with morphological anomalies, suggesting high levels of developmental instability. The broad geographic distribution of this phenomenon seems to exclude local environmental causes, but the source of instability is still to be identified. The goal of the present study was to collect quantitative data on the occurrence of phenodeviants in different populations, along with data on the patterns of genetic variation within and between populations, in order to investigate possible association between developmental instability and genetic features. In a sample of 11 populations of H. subterraneus, distributed in western and central Europe, we looked for phenodeviants, in particular with respect to trunk morphology, and studied genetic variation through the genotyping of microsatellite loci. Overall, no support was found to the idea that developmental instability in H. subterraneus is related to a specific patterns of genetic variation, including inbreeding estimates. We identified a major genetic partition that subdivides French populations from the others, and a low divergence among northwestern areas, which are possibly related to the post-glacial recolonization from southern refugia and/or to recent anthropogenic soil displacements. A weak correlation between individual number of leg bearing segments and the occurrence of trunk anomalies seems to support a trade-off between these two developmental traits. These results, complemented by preliminary data on developmental stability in two related species, suggest that the phenomenon has not a simple taxonomic distribution, while it exhibits an apparent localization in central and eastern Europe.

  13. Antibiotic free selection for the high level biosynthesis of a silk-elastin-like protein

    PubMed Central

    Barroca, Mário; Rodrigues, Paulo; Sobral, Rómulo; Costa, M. Manuela R.; Chaves, Susana R.; Machado, Raul; Casal, Margarida; Collins, Tony

    2016-01-01

    Silk-elastin-like proteins (SELPs) are a family of genetically engineered recombinant protein polymers exhibiting mechanical and biological properties suited for a wide range of applications in the biomedicine and materials fields. They are being explored as the next generation of biomaterials but low productivities and use of antibiotics during production undermine their economic viability and safety. We have developed an industrially relevant, scalable, fed-batch process for the high level production of a novel SELP in E. coli in which the commonly used antibiotic selection marker of the expression vector is exchanged for a post segregational suicide system, the separate-component-stabilisation system (SCS). SCS significantly augments SELP productivity but also enhances the product safety profile and reduces process costs by eliminating the use of antibiotics. Plasmid content increased following induction but no significant differences in plasmid levels were discerned when using SCS or the antibiotic selection markers under the controlled fed-batch conditions employed. It is suggested that the absence of competing plasmid-free cells improves host cell viability and enables increased productivity with SCS. With the process developed, 12.8 g L−1 purified SELP was obtained, this is the highest SELP productivity reported to date and clearly demonstrates the commercial viability of these promising polymers. PMID:27982135

  14. Evaluation of New Inorganic Sorbents for Strontium and Actinide Removal from High-Level Nuclear Waste Solutions

    SciTech Connect

    Hobbs, D.T.; Nyman, M.; Medvedev, D.G.; Tripathi, A.; Clearfield, A.

    2004-03-28

    Monosodium titanate (MST), a hydrous metal oxide sorbent, is the baseline material for the removal of 90Sr and alpha-emitting radionuclides (principally 238Pu, 239Pu, 240Pu and 237Np) from alkaline waste solutions generated during the processing of irradiated nuclear materials at the Savannah River Site. This material exhibits excellent performance characteristics for strontium removal. Plutonium removal is also good, but problematic at the estimated bonding concentration. We are currently developing new inorganic materials for improved sorption characteristics. These materials include sodium nonatitanates, pharmacosiderites and heteropolyniobates. We will present results evaluating the performance of these materials with simulated and actual high level nuclear waste solutions.

  15. High levels of dietary stearate promote adiposity and deteriorate hepatic insulin sensitivity

    PubMed Central

    2010-01-01

    Background Relatively little is known about the role of specific saturated fatty acids in the development of high fat diet induced obesity and insulin resistance. Here, we have studied the effect of stearate in high fat diets (45% energy as fat) on whole body energy metabolism and tissue specific insulin sensitivity. Methods C57Bl/6 mice were fed a low stearate diet based on palm oil or one of two stearate rich diets, one diet based on lard and one diet based on palm oil supplemented with tristearin (to the stearate level of the lard based diet), for a period of 5 weeks. Ad libitum fed Oxidative metabolism was assessed by indirect calorimetry at week 5. Changes in body mass and composition was assessed by DEXA scan analysis. Tissue specific insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp analysis and Western blot at the end of week 5. Results Indirect calorimetry analysis revealed that high levels of dietary stearate resulted in lower caloric energy expenditure characterized by lower oxidation of fatty acids. In agreement with this metabolic phenotype, mice on the stearate rich diets gained more adipose tissue mass. Whole body and tissue specific insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp and analysis of insulin induced PKBser473 phosphorylation. Whole body insulin sensitivity was decreased by all high fat diets. However, while insulin-stimulated glucose uptake by peripheral tissues was impaired by all high fat diets, hepatic insulin sensitivity was affected only by the stearate rich diets. This tissue-specific pattern of reduced insulin sensitivity was confirmed by similar impairment in insulin-induced phosphorylation of PKBser473 in both liver and skeletal muscle. Conclusion In C57Bl/6 mice, 5 weeks of a high fat diet rich in stearate induces a metabolic state favoring low oxidative metabolism, increased adiposity and whole body insulin resistance characterized by severe hepatic insulin resistance. These results

  16. Modeling of Stress Corrosion Cracking for High Level Radioactive-Waste Packages

    SciTech Connect

    Lu, S C; Gordon, G M; Andresen, P L; Herrera, M L

    2003-06-20

    A stress corrosion cracking (SCC) model has been adapted for performance prediction of high level radioactive-waste packages to be emplaced in the proposed Yucca Mountain radioactive-waste repository. SCC is one form of environmentally assisted cracking due to three factors, which must be present simultaneously: metallurgical susceptibility, critical environment, and static (or sustained) tensile stresses. For waste packages of the proposed Yucca Mountain repository, the outer barrier material is Alloy 22, a highly corrosion resistant alloy, the environment is represented by the water film present on the surface of the waste package from dripping or deliquescence of soluble salts present in any surface deposits, and the stress is principally the weld induced residual stress. SCC has historically been separated into ''initiation'' and ''propagation'' phases. Initiation of SCC will not occur on a smooth surface if the surface stress is below a threshold value defined as the threshold stress. Cracks can also initiate at and propagate from flaws (or defects) resulting from manufacturing processes (such as welding). To account for crack propagation, the slip dissolution/film rupture (SDFR) model is adopted to provide mathematical formulas for prediction of the crack growth rate. Once the crack growth rate at an initiated SCC is determined, the time to through-wall penetration for the waste package can be calculated. The SDFR model relates the advance (or propagation) of cracks, subsequent to the crack initiation from bare metal surface, to the metal oxidation transients that occur when the protective film at the crack tip is continually ruptured and repassivated. A crack, however, may reach the ''arrest'' state before it enters the ''propagation'' phase. There exists a threshold stress intensity factor, which provides a criterion for determining if an initiated crack or pre-existing manufacturing flaw will reach the ''arrest'' state. This paper presents the research

  17. Cytotoxic Th1 and Th17 cells infiltrate the intestinal mucosa of Behcet patients and exhibit high levels of TNF-α in early phases of the disease

    PubMed Central

    Emmi, Giacomo; Silvestri, Elena; Bella, Chiara Della; Grassi, Alessia; Benagiano, Marisa; Cianchi, Fabio; Squatrito, Danilo; Cantarini, Luca; Emmi, Lorenzo; Selmi, Carlo; Prisco, Domenico; D’Elios, Mario Milco

    2016-01-01

    Abstract Background: Gastrointestinal involvement is one of the most serious in Behçet disease, potentially leading to severe complications. Aim of this study was to investigate at mucosal level the T-cell responses in Behçet patients with early intestinal involvement. Methods: We isolated T cells from intestinal mucosa of 8 patients with intestinal symptoms started within 6 months. T lymphocytes were cloned and analyzed for surface phenotype and cytokines production. Results: We obtained 382 T-cell clones: 324 were CD4+ and 58 were CD8+. Within the 324 CD4+ clones, 195 were able to secrete IFN-γ and TNF-α, but not IL-4, nor IL-17 thus showing a polarized Th1 profile, whereas CD4 clones producing both IFN-γ and IL-17 (Th1/Th17 profile) were 79. Likewise, the number of CD8 clones producing type 1 cytokines was higher than those of CD8 clones producing both type 1 and 2 cytokines. Almost all intestinal-derived T-cell clones expressed perforin-mediated cytotoxicity and Fas–Fas Ligand-mediated pro-apoptotic activity. Conclusions: Our results indicate that in the early stages of the disease, both Th1 and Th17 cells drive inflammation leading to mucosal damage via abnormal and long-lasting cytokines production as well as via both perforin- and Fas–Fas ligand-mediated cytotoxicity. Finally, all the T cells at mucosal level were able to produce large amount of TNF-α, suggesting that its production is a property of intestinal T cells of patients with early active intestinal disease. These results support the therapy with anti-TNF-α agents and suggest the use of anti-IL-17 monoclonal antibodies in Behçet patients with early intestinal involvement. PMID:27930541

  18. Honey bees (Apis mellifera) reared in brood combs containing high levels of pesticide residues exhibit increased susceptibility to Nosema (Microsporidia) infection.

    PubMed

    Wu, Judy Y; Smart, Matthew D; Anelli, Carol M; Sheppard, Walter S

    2012-03-01

    Nosema ceranae and pesticide exposure can contribute to honey bee health decline. Bees reared from brood comb containing high or low levels of pesticide residues were placed in two common colony environments. One colony was inoculated weekly with N. ceranae spores in sugar syrup and the other colony received sugar syrup only. Worker honey bees were sampled weekly from the treatment and control colonies and analyzed for Nosema spore levels. Regardless of the colony environment (spores+syrup added or syrup only added), a higher proportion of bees reared from the high pesticide residue brood comb became infected with N. ceranae, and at a younger age, compared to those reared in low residue brood combs. These data suggest that developmental exposure to pesticides in brood comb increases the susceptibility of bees to N. ceranae infection.

  19. Nasal Polyp-Derived Mesenchymal Stromal Cells Exhibit Lack of Immune-Associated Molecules and High Levels of Stem/Progenitor Cells Markers

    PubMed Central

    de Oliveira, Pedro Wey Barbosa; Pezato, Rogério; Agudelo, Juan Sebastian Henao; Perez-Novo, Claudina Angela; Berghe, Wim Vanden; Câmara, Niels Olsen; de Almeida, Danilo Candido; Gregorio, Luís Carlos

    2017-01-01

    Mesenchymal stromal cells (MSCs) are considered adult progenitor stem cells and have been studied in a multitude of tissues. In this context, the microenvironment of nasal polyp tissue has several inflammatory cells, but their stroma compartment remains little elucidated. Hence, we isolated MSCs from nasal polyps Polyp-MSCs (PO-MSCs) and compared their molecular features and gene expression pattern with bone marrow-derived MSCs (BM-MSCs). Initially, both PO-MSCs and BM-MSCs were isolated, cultivated, and submitted to morphologic, differentiation, phenotypic, immunosuppressive, and gene expression assays. Compared to BM-MSCs, PO-MSCs showed normal morphology and similar osteogenic/adipogenic differentiation potential, but their immunophenotyping showed lack of immune-associated molecules (e.g., CD117, HLA-DR, PDL-1, and PDL-2), which was linked with less immunoregulatory abilities such as (i) inhibition of lymphocytes proliferation and (ii) regulatory T cell expansion. Furthermore, we detected in the PO-MSCs a distinct gene expression profile in comparison with BM-MSCs. PO-MSC expressed higher levels of progenitor stem cells specific markers (e.g., CD133 and ABCB1), while BM-MSCs showed elevated expression of cytokines and growth factors (e.g., FGF10, KDR, and GDF6). The gene ontology analysis showed that the differentially modulated genes in PO-MSC were related with matrix remodeling process and hexose and glucose transport. For BM-MSCs, the highly expressed genes were associated with behavior, angiogenesis, blood vessel morphogenesis, cell–cell signaling, and regulation of response to external stimulus. Thus, these results suggest that PO-MSCs, while sharing similar aspects with BM-MSCs, express a different profile of molecules, which presumably can be implicated in the development of nasal polyp tissue. PMID:28194153

  20. Does high serum uric acid level cause aspirin resistance?

    PubMed

    Yildiz, Bekir S; Ozkan, Emel; Esin, Fatma; Alihanoglu, Yusuf I; Ozkan, Hayrettin; Bilgin, Murat; Kilic, Ismail D; Ergin, Ahmet; Kaftan, Havane A; Evrengul, Harun

    2016-06-01

    In patients with coronary artery disease (CAD), though aspirin inhibits platelet activation and reduces atherothrombotic complications, it does not always sufficiently inhibit platelet function, thereby causing a clinical situation known as aspirin resistance. As hyperuricemia activates platelet turnover, aspirin resistance may be specifically induced by increased serum uric acid (SUA) levels. In this study, we thus investigated the association between SUA level and aspirin resistance in patients with CAD. We analyzed 245 consecutive patients with stable angina pectoris (SAP) who in coronary angiography showed more than 50% occlusion in a major coronary artery. According to aspirin resistance, two groups were formed: the aspirin resistance group (Group 1) and the aspirin-sensitive group (Group 2). Compared with those of Group 2, patients with aspirin resistance exhibited significantly higher white blood cell counts, neutrophil counts, neutrophil-to-lymphocyte ratios, SUA levels, high-sensitivity C-reactive protein levels, and fasting blood glucose levels. After multivariate analysis, a high level of SUA emerged as an independent predictor of aspirin resistance. The receiver-operating characteristic analysis provided a cutoff value of 6.45 mg/dl for SUA to predict aspirin resistance with 79% sensitivity and 65% specificity. Hyperuricemia may cause aspirin resistance in patients with CAD and high SUA levels may indicate aspirin-resistant patients. Such levels should thus recommend avoiding heart attack and stroke by adjusting aspirin dosage.

  1. Surprising Alteration of Antibacterial Activity of 5″-Modified Neomycin against Resistant Bacteria

    PubMed Central

    Zhang, Jianjun; Chiang, Fang-I; Wu, Long; Czyryca, Przemyslaw Greg; Li, Ding; Chang, Cheng-Wei Tom

    2009-01-01

    A facile synthetic protocol for the production of neomycin B derivatives with various modifications at the 5″ position has been developed. Structural activity relationship (SAR) against aminoglycoside resistant bacteria equipped with various aminoglycoside-modifying enzymes (AME's) was investigated. Enzymatic and molecular modeling studies reveal that the superb substrate promiscuity of AME's allows the resistant bacteria to cope with diverse structural modifications despite the observation that several derivatives show enhanced antibacterial activity than the parent neomycin. Surprisingly, when testing synthetic neomycin derivatives against other human pathogens, two leads exhibit prominent activity against both Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) that are known to exert high level of resistance against clinically used aminoglycosides. These findings can be extremely useful in developing new aminoglycoside antibiotics against resistant bacteria. Our result also suggests that new biological and antimicrobial activities can be obtained by chemical modifications of old drugs. PMID:19012394

  2. Antimicrobial resistance of Escherichia coli isolated from chickens with colibacillosis in and around Harare, Zimbabwe.

    PubMed

    Saidi, Bamusi; Mafirakureva, Prettimore; Mbanga, Joshua

    2013-03-01

    Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC), can lead to great economic losses in the poultry industry. The aim of this study was to determine the prevalence of antibiotic resistance and antibiotic resistance patterns in APEC in Zimbabwe. From 503 chickens diagnosed with colibacillosis, 103 E. coli isolates were obtained. Isolation and identification of E. coli were carried out using microscopy and biochemical tests. The disc diffusion method was used to determine antibiotic susceptibility of the isolates to 8 commercial antibiotics. Many isolates exhibited resistance to more than one antibiotic. Antibiogram profiles indicated maximum resistance to tetracycline (100%), bacitracin (100%), and cloxacillin (100%) and a high prevalence of resistance to ampicillin (94.1%). However; there were high prevalences of sensitivity to ciprofloxacin (100%) and gentamycin (97.1%). The isolates showed moderate rates of sensitivity to chloramphenicol and neomycin. All isolates in this study showed multidrug resistance because they were all resistant to 3 or more antibiotics. Seven multidrug resistance patterns were observed. The most common pattern (resistance to ampicillin, bacitracin, cloxacillin, and tetracycline) was exhibited by 30 isolates. Our findings show that there is emerging drug resistance in APEC associated with colibacillosis in Zimbabwe. The observed high level of multidrug resistance could hamper the treatment of colibacillosis in Zimbabwe.

  3. Alternatives Generation and Analysis for Heat Removal from High Level Waste Tanks

    SciTech Connect

    WILLIS, W.L.

    2000-06-15

    This document addresses the preferred combination of design and operational configurations to provide heat removal from high-level waste tanks during Phase 1 waste feed delivery to prevent the waste temperature from exceeding tank safety requirement limits. An interim decision for the preferred method to remove the heat from the high-level waste tanks during waste feed delivery operations is presented herein.

  4. Hi-LAB: A New Measure of Aptitude for High-Level Language Proficiency

    ERIC Educational Resources Information Center

    Linck, Jared A.; Hughes, Meredith M.; Campbell, Susan G.; Silbert, Noah H.; Tare, Medha; Jackson, Scott R.; Smith, Benjamin K.; Bunting, Michael F.; Doughty, Catherine J.

    2013-01-01

    Few adult second language (L2) learners successfully attain high-level proficiency. Although decades of research on beginning to intermediate stages of L2 learning have identified a number of predictors of the rate of acquisition, little research has examined factors relevant to predicting very high levels of L2 proficiency. The current study,…

  5. Inspection and evaluation of Nuclear Fuel Services high-level waste storage system, program plan

    NASA Astrophysics Data System (ADS)

    1980-01-01

    Information concerning the condition of the high-level waste tanks at the Western New York State Nuclear Service center near West Valley, New York is presented. This information is to be used in evaluating the safety of continued storage and in the development of alternatives for final disposition of the high-level waste.

  6. 78 FR 14840 - U.S.-EU High Level Regulatory Cooperation Forum-Stakeholder Session

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-07

    ... BUDGET U.S.-EU High Level Regulatory Cooperation Forum--Stakeholder Session AGENCY: Office of Management... will hold a public meeting of the U.S.-EU High Level Regulatory Cooperation Forum (the ``Forum'') in...-cooperation-forum . Oral Presentations: Any persons wishing to present an oral statement at the public...

  7. 78 FR 70281 - United States-Mexico High Level Economic Dialogue

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-25

    ... United States-Mexico High Level Economic Dialogue AGENCY: International Trade Administration, Commerce... Register notice on the United States-Mexico High Level Economic Dialogue. DATES: The agency must receive... largest export market and third largest overall trading partner. The United States, in turn, is...

  8. High level language for measurement complex control based on the computer E-100I

    NASA Technical Reports Server (NTRS)

    Zubkov, B. V.

    1980-01-01

    A high level language was designed to control the process of conducting an experiment using the computer "Elektrinika-1001". Program examples are given to control the measuring and actuating devices. The procedure of including these programs in the suggested high level language is described.

  9. Characteristics Data Base: Programmer's guide to the High-Level Waste Data Base

    SciTech Connect

    Jones, K.E. ); Salmon, R. )

    1990-08-01

    The High-Level Waste Data Base is a menu-driven PC data base developed as part of OCRWM's technical data base on the characteristics of potential repository wastes, which also includes spent fuel and other materials. This programmer's guide completes the documentation for the High-Level Waste Data Base, the user's guide having been published previously. 3 figs.

  10. F14512, a polyamine-vectorized inhibitor of topoisomerase II, exhibits a marked anti-tumor activity in ovarian cancer.

    PubMed

    Thibault, Benoît; Clement, Emily; Zorza, Grégoire; Meignan, Samuel; Delord, Jean-Pierre; Couderc, Bettina; Bailly, Christian; Narducci, Fabrice; Vandenberghe, Isabelle; Kruczynski, Anna; Guilbaud, Nicolas; Ferré, Pierre; Annereau, Jean-Philippe

    2016-01-01

    Epithelial ovarian cancer is the fourth cause of death among cancer-bearing women and frequently associated with carboplatin resistance, underlining the need for more efficient and targeted therapies. F14512 is an epipodophylotoxin-core linked to a spermine chain which enters cells via the polyamine transport system (PTS). Here, we investigate this novel concept of vectorization in ovarian cancer. We compared the effects of etoposide and F14512 on a panel of five carboplatin-sensitive or resistant ovarian cancer models. We assessed the incorporation of F17073, a spermine-linked fluorescent probe, in these cells and in 18 clinical samples. We then showed that F14512 exhibits a high anti-proliferative and pro-apoptotic activity, particularly in cells with high levels of F17073 incorporation. Consistently, F14512 significantly inhibited tumor growth compared to etoposide, in a cisplatin-resistant A2780R subcutaneous model, at a dose of 1.25 mg/kg. In addition, ex vivo analysis indicated that 15 out of 18 patients presented a higher F17073 incorporation into tumor cells compared to normal cells. Overall, our data suggest that F14512, a targeted drug with a potent anti-tumor efficacy, constitutes a potential new therapy for highly PTS-positive and platinum-resistant ovarian cancer-bearing patients.

  11. Precautionary Practices of Healthcare Workers Who Disinfect Medical and Dental Devices Using High-Level Disinfectants

    PubMed Central

    Henn, Scott A.; Boiano, James M.; Steege, Andrea L.

    2016-01-01

    Background High-level disinfectants (HLDs) are used throughout the healthcare industry to chemically disinfect reusable, semicritical medical and dental devices to control and prevent healthcare-associated infections among patient populations. Workers who use HLDs are at risk of exposure to these chemicals, some of which are respiratory and skin irritants and sensitizers. Objective To evaluate exposure controls used and to better understand impediments to healthcare workers using personal protective equipment while handling HLDs. Design Web-based survey. Participants A targeted sample of members of professional practice organizations representing nurses, technologists/technicians, dental professionals, respiratory therapists, and others who reported handling HLDs in the previous 7 calendar days. Participating organizations invited either all or a random sample of members via email, which included a hyperlink to the survey. Methods Descriptive analyses were conducted including simple frequencies and prevalences. Results A total of 4,657 respondents completed the survey. The HLDs used most often were glutaraldehyde (59%), peracetic acid (16%), and ortho-phthalaldehyde (15%). Examples of work practices or events that could increase exposure risk included failure to wear water-resistant gowns (44%); absence of standard procedures for minimizing exposure (19%); lack of safe handling training (17%); failure to wear protective gloves (9%); and a spill/leak of HLD during handling (5%). Among all respondents, 12% reported skin contact with HLDs, and 33% of these respondents reported that they did not always wear gloves. Conclusion Findings indicated that precautionary practices were not always used, underscoring the importance of improved employer and worker training and education regarding HLD hazards. PMID:25633000

  12. Precautionary practices of healthcare workers who disinfect medical and dental devices using high-level disinfectants.

    PubMed

    Henn, Scott A; Boiano, James M; Steege, Andrea L

    2015-02-01

    BACKGROUND High-level disinfectants (HLDs) are used throughout the healthcare industry to chemically disinfect reusable, semicritical medical and dental devices to control and prevent healthcare-associated infections among patient populations. Workers who use HLDs are at risk of exposure to these chemicals, some of which are respiratory and skin irritants and sensitizers. OBJECTIVE To evaluate exposure controls used and to better understand impediments to healthcare workers using personal protective equipment while handling HLDs. DESIGN Web-based survey. PARTICIPANTS A targeted sample of members of professional practice organizations representing nurses, technologists/technicians, dental professionals, respiratory therapists, and others who reported handling HLDs in the previous 7 calendar days. Participating organizations invited either all or a random sample of members via email, which included a hyperlink to the survey. METHODS Descriptive analyses were conducted including simple frequencies and prevalences. RESULTS A total of 4,657 respondents completed the survey. The HLDs used most often were glutaraldehyde (59%), peracetic acid (16%), and ortho-phthalaldehyde (15%). Examples of work practices or events that could increase exposure risk included failure to wear water-resistant gowns (44%); absence of standard procedures for minimizing exposure (19%); lack of safe handling training (17%); failure to wear protective gloves (9%); and a spill/leak of HLD during handling (5%). Among all respondents, 12% reported skin contact with HLDs, and 33% of these respondents reported that they did not always wear gloves. CONCLUSION Findings indicated that precautionary practices were not always used, underscoring the importance of improved employer and worker training and education regarding HLD hazards.

  13. Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

    SciTech Connect

    Farmer, J.C.; Van Konynenburg, R.A.; McCright, R.D. ); Gdowski, G.E. )

    1988-06-01

    Three copper-based alloys, CDA 102 (oxygen-free, high-purity copper), CDA 613 (aluminum bronze), and CDA 715 (Cu-30Ni), are candidates for the fabrication of high-level radioactive-waste disposal containers. Waste will include spent fuel assemblies from reactors as well as borosilicate glass, and will be sent to the prospective repository site at Yucca Mountain in Nye County, Nevada. The decay of radionuclides will result in the generation of substantial heat and in fluxes of gamma radiation outside the containers. In this environment, container materials might degrade by atmospheric oxidation, general aqueous phase corrosion, localized corrosion (LC), and stress corrosion cracking (SCC). This volume is a critical survey of available data on pitting and crevice corrosion of the copper-based candidates. Pitting and crevice corrosion are two of the most common forms of LC of these materials. Data on the SCC of these alloys is surveyed in Volume 4. Pitting usually occurs in water that contains low concentrations of bicarbonate and chloride anions, such as water from Well J-13 at the Nevada Test Site. Consequently, this mode of degradation might occur in the repository environment. Though few quantitative data on LC were found, a tentative ranking based on pitting corrosion, local dealloying, crevice corrosion, and biofouling is presented. CDA 102 performs well in the categories of pitting corrosion, local dealloying, and biofouling, but susceptibility to crevice corrosion diminishes its attractiveness as a candidate. The cupronickel alloy, CDA 715, probably has the best overall resistance to such localized forms of attack. 123 refs., 11 figs., 3 tabs.

  14. High level seismic/vibrational tests at the HDR: An overview

    SciTech Connect

    Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J.; Schrammel, D.; Malcher, L.; Steinhilber, H.; Costello, J.F.

    1991-12-31

    As part of the Phase II testing at the HDR Test Facility in Kahl/Main, FRG, two series of high-level seismic/vibrational experiments were performed. In the first of these (SHAG) a coast-down shaker, mounted on the reactor operating floor and capable of generating 1000 tonnes of force, was used to investigate full-scale structural response, soil-structure interaction (SSI), and piping/equipment response at load levels equivalent to those of a design basis earthquake. The HDR soil/structure system was tested to incipient failure exhibiting highly nonlinear response. In the load transmission from structure to piping/equipment significant response amplifications and shifts to higher frequencies occurred. The performance of various pipe support configurations was evaluated. This latter effort was continued in the second series of tests (SHAM), in which an in-plant piping system was investigated at simulated seismic loads (generated by two servo-hydraulic actuators each capable of generating 40 tonnes of force), that exceeded design levels manifold and resulted in considerable pipe plastification and failure of some supports (snubbers). The evaluation of six different support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is essential to limiting pipe stresses. Pipe strains at loads exceeding the design level eightfold were still tolerable, indicating that pipe failure even under extreme seismic loads is unlikely inspite of multiple support failures. Conservatively, an excess capacity (margin) of at least four was estimated for the piping system, and the pipe damping was found to be 4%. Comparisons of linear and nonlinear computational results with measurements showed that analytical predictions have wide scatter and do not necessarily yield conservative responses, underpredicting, in particular, peak support forces.

  15. High level seismic/vibrational tests at the HDR: An overview

    SciTech Connect

    Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J. ); Schrammel, D.; Malcher, L. ); Steinhilber, H. ); Costello, J.F. . Office of Nuclear Regulatory Research)

    1991-01-01

    As part of the Phase II testing at the HDR Test Facility in Kahl/Main, FRG, two series of high-level seismic/vibrational experiments were performed. In the first of these (SHAG) a coast-down shaker, mounted on the reactor operating floor and capable of generating 1000 tonnes of force, was used to investigate full-scale structural response, soil-structure interaction (SSI), and piping/equipment response at load levels equivalent to those of a design basis earthquake. The HDR soil/structure system was tested to incipient failure exhibiting highly nonlinear response. In the load transmission from structure to piping/equipment significant response amplifications and shifts to higher frequencies occurred. The performance of various pipe support configurations was evaluated. This latter effort was continued in the second series of tests (SHAM), in which an in-plant piping system was investigated at simulated seismic loads (generated by two servo-hydraulic actuators each capable of generating 40 tonnes of force), that exceeded design levels manifold and resulted in considerable pipe plastification and failure of some supports (snubbers). The evaluation of six different support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is essential to limiting pipe stresses. Pipe strains at loads exceeding the design level eightfold were still tolerable, indicating that pipe failure even under extreme seismic loads is unlikely inspite of multiple support failures. Conservatively, an excess capacity (margin) of at least four was estimated for the piping system, and the pipe damping was found to be 4%. Comparisons of linear and nonlinear computational results with measurements showed that analytical predictions have wide scatter and do not necessarily yield conservative responses, underpredicting, in particular, peak support forces.

  16. Production of Cloned Miniature Pigs Expressing High Levels of Human Apolipoprotein(a) in Plasma

    PubMed Central

    Ozawa, Masayuki; Himaki, Takehiro; Ookutsu, Shoji; Mizobe, Yamato; Ogawa, Junki; Miyoshi, Kazuchika; Yabuki, Akira; Fan, Jianglin; Yoshida, Mitsutoshi

    2015-01-01

    High lipoprotein(a) [Lp(a)] levels are a major risk factor for the development of atherosclerosis. However, because apolipoprotein(a) [apo(a)], the unique component of Lp(a), is found only in primates and humans, the study of human Lp(a) has been hampered due to the lack of appropriate animal models. Using somatic cell nuclear transfer (SCNT) techniques, we produced transgenic miniature pigs expressing human apo(a) in the plasma. First, we placed the hemagglutinin (HA)-tagged cDNA of human apo(a) under the control of the β-actin promoter and cytomegalovirus enhancer, and then introduced this construct into kidney epithelial cells. Immunostaining of cells with anti-HA antibody allowed identification of cells stably expressing apo(a); one of the positive clones was used to provide donor cells for SCNT, yielding blastocysts that expressed apo(a). Immunohistochemical analysis of tissue sections and RT-PCR analysis of total RNA from organs of cloned piglet revealed that apo(a) is expressed in various tissues/organs including heart, liver, kidney, and intestine. More importantly, a transgenic line exhibited a high level (>400 mg/dL) of Lp(a) in plasma, and the transgenic apo(a) gene was transmitted to the offspring. Thus, we generated a human apo(a)–transgenic miniature pig that can be used as a model system to study advanced atherosclerosis related to human disease. The anatomical and physiological similarities between the swine and human cardiovascular systems will make this pig model a valuable source of information on the role of apo(a) in the formation of atherosclerosis, as well as the mechanisms underlying vascular health and disease. PMID:26147378

  17. Population Genetic Structure of a Centipede Species with High Levels of Developmental Instability

    PubMed Central

    Fusco, Giuseppe; Leśniewska, Małgorzata; Congiu, Leonardo; Bertorelle, Giorgio

    2015-01-01

    European populations of the geophilomorph centipede Haplophilus subterraneus show a high proportion of individuals with morphological anomalies, suggesting high levels of developmental instability. The broad geographic distribution of this phenomenon seems to exclude local environmental causes, but the source of instability is still to be identified. The goal of the present study was to collect quantitative data on the occurrence of phenodeviants in different populations, along with data on the patterns of genetic variation within and between populations, in order to investigate possible association between developmental instability and genetic features. In a sample of 11 populations of H. subterraneus, distributed in western and central Europe, we looked for phenodeviants, in particular with respect to trunk morphology, and studied genetic variation through the genotyping of microsatellite loci. Overall, no support was found to the idea that developmental instability in H. subterraneus is related to a specific patterns of genetic variation, including inbreeding estimates. We identified a major genetic partition that subdivides French populations from the others, and a low divergence among northwestern areas, which are possibly related to the post-glacial recolonization from southern refugia and/or to recent anthropogenic soil displacements. A weak correlation between individual number of leg bearing segments and the occurrence of trunk anomalies seems to support a trade-off between these two developmental traits. These results, complemented by preliminary data on developmental stability in two related species, suggest that the phenomenon has not a simple taxonomic distribution, while it exhibits an apparent localization in central and eastern Europe. PMID:26029915

  18. Low-temperature lithium diffusion in simulated high-level boroaluminosilicate nuclear waste glasses

    SciTech Connect

    Neeway, James J.; Kerisit, Sebastien N.; Gin, Stephane; Wang, Zhaoying; Zhu, Zihua; Ryan, Joseph V.

    2014-12-01

    Ion exchange is recognized as an integral, if underrepresented, mechanism influencing glass corrosion. However, due to the formation of various alteration layers in the presence of water, it is difficult to conclusively deconvolute the mechanisms of ion exchange from other processes occurring simultaneously during corrosion. In this work, an operationally inert non-aqueous solution was used as an alkali source material to isolate ion exchange and study the solid-state diffusion of lithium. Specifically, the experiments involved contacting glass coupons relevant to the immobilization of high-level nuclear waste, SON68 and CJ-6, which contained Li in natural isotope abundance, with a non-aqueous solution of 6LiCl dissolved in dimethyl sulfoxide at 90 °C for various time periods. The depth profiles of major elements in the glass coupons were measured using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Lithium interdiffusion coefficients, DLi, were then calculated based on the measured depth profiles. The results indicate that the penetration of 6Li is rapid in both glasses with the simplified CJ-6 glass (D6Li ≈ 4.0-8.0 × 10-21 m2/s) exhibiting faster exchange than the more complex SON68 glass (DLi ≈ 2.0-4.0 × 10-21 m2/s). Additionally, sodium ions present in the glass were observed to participate in ion exchange reactions; however, different diffusion coefficients were necessary to fit the diffusion profiles of the two alkali ions. Implications of the diffusion coefficients obtained in the absence of alteration layers to the long-term performance of nuclear waste glasses in a geological repository system are also discussed.

  19. Mitochondrial DNA exhibits resistance to induced point and deletion mutations

    PubMed Central

    Valente, William J.; Ericson, Nolan G.; Long, Alexandra S.; White, Paul A.; Marchetti, Francesco; Bielas, Jason H.

    2016-01-01

    The accumulation of somatic mitochondrial DNA (mtDNA) mutations contributes to the pathogenesis of human disease. Currently, mitochondrial mutations are largely considered results of inaccurate processing of its heavily damaged genome. However, mainly from a lack of methods to monitor mtDNA mutations with sufficient sensitivity and accuracy, a link between mtDNA damage and mutation has not been established. To test the hypothesis that mtDNA-damaging agents induce mtDNA mutations, we exposed MutaTMMouse mice to benzo[a]pyrene (B[a]P) or N-ethyl-N-nitrosourea (ENU), daily for 28 consecutive days, and quantified mtDNA point and deletion mutations in bone marrow and liver using our newly developed Digital Random Mutation Capture (dRMC) and Digital Deletion Detection (3D) assays. Surprisingly, our results demonstrate mutagen treatment did not increase mitochondrial point or deletion mutation frequencies, despite evidence both compounds increase nuclear DNA mutations and demonstrated B[a]P adduct formation in mtDNA. These findings contradict models of mtDNA mutagenesis that assert the elevated rate of mtDNA mutation stems from damage sensitivity and abridged repair capacity. Rather, our results demonstrate induced mtDNA damage does not readily convert into mutation. These findings suggest robust mitochondrial damage responses repress induced mutations after mutagen exposure. PMID:27550180

  20. Why Low Bounce Balls Exhibit High Rolling Resistance

    ERIC Educational Resources Information Center

    Cross, Rod

    2015-01-01

    A simple experiment is described to measure the coefficient of rolling friction for a low bounce ball rolling on a horizontal surface. As observed previously by others, the coefficient increased with rolling speed. The energy loss due to rolling friction can be explained in terms of the measured coefficient of restitution for the ball, meaning…

  1. Ontological Problem-Solving Framework for Assigning Sensor Systems and Algorithms to High-Level Missions

    PubMed Central

    Qualls, Joseph; Russomanno, David J.

    2011-01-01

    The lack of knowledge models to represent sensor systems, algorithms, and missions makes opportunistically discovering a synthesis of systems and algorithms that can satisfy high-level mission specifications impractical. A novel ontological problem-solving framework has been designed that leverages knowledge models describing sensors, algorithms, and high-level missions to facilitate automated inference of assigning systems to subtasks that may satisfy a given mission specification. To demonstrate the efficacy of the ontological problem-solving architecture, a family of persistence surveillance sensor systems and algorithms has been instantiated in a prototype environment to demonstrate the assignment of systems to subtasks of high-level missions. PMID:22164081

  2. Incorporation of Bacterial Blight Resistance Genes Into Lowland Rice Cultivar Through Marker-Assisted Backcross Breeding.

    PubMed

    Pradhan, Sharat Kumar; Nayak, Deepak Kumar; Pandit, Elssa; Behera, Lambodar; Anandan, Annamalai; Mukherjee, Arup Kumar; Lenka, Srikanta; Barik, Durga Prasad

    2016-07-01

    Bacterial blight (BB) of rice caused by Xanthomonas oryzae pv. oryzae is a major disease of rice in many rice growing countries. Pyramided lines carrying two BB resistance gene combinations (Xa21+xa13 and Xa21+xa5) were developed in a lowland cultivar Jalmagna background through backcross breeding by integrating molecular markers. In each backcross generation, markers closely linked to the disease resistance genes were used to select plants possessing the target genes. Background selection was continued in those plants carrying resistant genes until BC(3) generation. Plants having the maximum contribution from the recurrent parent genome were selected in each generation and hybridized with the recipient parent. The BB-pyramided line having the maximum recipient parent genome recovery of 95% was selected among BC3F1 plants and selfed to isolate homozygous BC(3)F(2) plants with different combinations of BB resistance genes. Twenty pyramided lines with two resistance gene combinations exhibited high levels of tolerance against the BB pathogen. In order to confirm the resistance, the pyramided lines were inoculated with different X. oryzae pv. oryzae strains of Odisha for bioassay. The genotypes with combination of two BB resistance genes conferred high levels of resistance to the predominant X. oryzae pv. oryzae isolates prevalent in the region. The pyramided lines showed similarity with the recipient parent with respect to major agro-morphologic traits.

  3. Retrieved waste properties and high-level waste critical component ratios for privatization waste feed delivery

    SciTech Connect

    Peters, B.B.

    1998-03-04

    The purpose for this document is to provide the basis for the retrieved waste properties and high-level waste critical component ratios specified in the System Specification for the Double-Shell Tank System.

  4. Thermoelectric device exhibiting decreased stress

    SciTech Connect

    Heath, D.L.; Chou, D.J.

    1985-02-05

    A thermoelectric device exhibiting both structural integrity and decreased stress across the device notwithstanding the application of thermally cycled temperature differentials thereacross includes, electrically interconnected thermoelectric elements and a rigidly affixed substrate. Thermal stress is relieved by using flexible conductors to interconnect the thermoelectric elements, and by the use of a flexile joint to attach a second substrate to the remainder of the device. Complete elimination of the second substrate may also be used to eliminate stress. Presence of the rigidly affixed substrate gives the device sufficient structural integrity to enable it to withstand rugged conditions.

  5. Large holograms in traveling exhibitions

    NASA Astrophysics Data System (ADS)

    Christakis, Anne-Marie

    1994-01-01

    The presentation of large holograms in travelling exhibitions has always posed problems, mainly due to lack of space. The Museum of Holography was consequently required to develop, with Jean-Francois Moreau, display consoles which are light, affordable and completely detachable. In a permanent exposition at the Forum des Halles in Paris, the Museum displays a room with 22 holograms, each measuring 1 m X 1 m, in a structure designed by the architect Fabien Vienne. The different systems used by the Museum are presented here.

  6. Integrated Corrosion Facility for long-term testing of candidate materials for high-level radioactive waste containment

    SciTech Connect

    Estill, J.C.; Dalder, E.N.C.; Gdowski, G.E.; McCright, R.D.

    1994-10-01

    A long-term-testing facility, the Integrated Corrosion Facility (I.C.F.), is being developed to investigate the corrosion behavior of candidate construction materials for high-level-radioactive waste packages for the potential repository at Yucca Mountain, Nevada. Corrosion phenomena will be characterized in environments considered possible under various scenarios of water contact with the waste packages. The testing of the materials will be conducted both in the liquid and high humidity vapor phases at 60 and 90{degrees}C. Three classes of materials with different degrees of corrosion resistance will be investigated in order to encompass the various design configurations of waste packages. The facility is expected to be in operation for a minimum of five years, and operation could be extended to longer times if warranted. A sufficient number of specimens will be emplaced in the test environments so that some can be removed and characterized periodically. The corrosion phenomena to be characterized are general, localized, galvanic, and stress corrosion cracking. The long-term data obtained from this study will be used in corrosion mechanism modeling, performance assessment, and waste package design. Three classes of materials are under consideration. The corrosion resistant materials are high-nickel alloys and titanium alloys; the corrosion allowance materials are low-alloy and carbon steels; and the intermediate corrosion resistant materials are copper-nickel alloys.

  7. The antibiotic resistance arrow of time: efflux pump induction is a general first step in the evolution of mycobacterial drug resistance.

    PubMed

    Schmalstieg, Aurelia M; Srivastava, Shashikant; Belkaya, Serkan; Deshpande, Devyani; Meek, Claudia; Leff, Richard; van Oers, Nicolai S C; Gumbo, Tawanda

    2012-09-01

    We hypothesize that low-level efflux pump expression is the first step in the development of high-level drug resistance in mycobacteria. We performed 28-day azithromycin dose-effect and dose-scheduling studies in our hollow-fiber model of disseminated Mycobacterium avium-M. intracellulare complex. Both microbial kill and resistance emergence were most closely linked to the within-macrophage area under the concentration-time curve (AUC)/MIC ratio. Quantitative PCR revealed that subtherapeutic azithromycin exposures over 3 days led to a 56-fold increase in expression of MAV_3306, which encodes a putative ABC transporter, and MAV_1406, which encodes a putative major facilitator superfamily pump, in M. avium. By day 7, a subpopulation of M. avium with low-level resistance was encountered and exhibited the classic inverted U curve versus AUC/MIC ratios. The resistance was abolished by an efflux pump inhibitor. While the maximal microbial kill started to decrease after day 7, a population with high-level azithromycin resistance appeared at day 28. This resistance could not be reversed by efflux pump inhibitors. Orthologs of pumps encoded by MAV_3306 and MAV_1406 were identified in Mycobacterium tuberculosis, Mycobacterium leprae, Mycobacterium marinum, Mycobacterium abscessus, and Mycobacterium ulcerans. All had highly conserved protein secondary structures. We propose that induction of several efflux pumps is the first step in a general pathway to drug resistance that eventually leads to high-level chromosomal-mutation-related resistance in mycobacteria as ordered events in an "antibiotic resistance arrow of time."

  8. Combined strength and power training in high-level amateur football during the competitive season: a randomised-controlled trial.

    PubMed

    Faude, Oliver; Roth, Ralf; Di Giovine, Dario; Zahner, Lukas; Donath, Lars

    2013-01-01

    We aimed to analyse the effects of combined strength and power training during the competitive season on physical fitness in high-level amateur football players. Sixteen male players (22.5 (SD 2.5) years, 1.79 (0.05) m, 76.8 (6.1) kg) from one team were randomly assigned to either a strength training (ST, N = 8) or a control (CON, N = 8) group. ST conducted lower extremity resistance exercises combined with plyometrics and/or sprints 2 × 30 min per week for 7 weeks. CON performed technical-tactical training during the same time period. Before and after training several physical fitness parameters were assessed: one-repetition maximum (1-RM, half squat), isometric peak strength and rate of force development (RFD, leg press), jump height (countermovement, CMJ, drop jump, DJ), sprint times, agility, and intermittent endurance. Large significant test × group interactions were found for 1-RM, CMJ, and DJ reactivity index with increases in CT relative to CON(+11 to 18%). Although not significant (P < 0.20), likely practically relevant effects were observed for isometric peak strength and RFD (+24 to 29%). We found no relevant interaction effects for agility, sprint times, and intermittent endurance. A 7-week in-season combined strength and power training program can improve relevant strength and jump parameters in high-level amateur football players.

  9. Collaborative virtual environments art exhibition

    NASA Astrophysics Data System (ADS)

    Dolinsky, Margaret; Anstey, Josephine; Pape, Dave E.; Aguilera, Julieta C.; Kostis, Helen-Nicole; Tsoupikova, Daria

    2005-03-01

    This panel presentation will exhibit artwork developed in CAVEs and discuss how art methodologies enhance the science of VR through collaboration, interaction and aesthetics. Artists and scientists work alongside one another to expand scientific research and artistic expression and are motivated by exhibiting collaborative virtual environments. Looking towards the arts, such as painting and sculpture, computer graphics captures a visual tradition. Virtual reality expands this tradition to not only what we face, but to what surrounds us and even what responds to our body and its gestures. Art making that once was isolated to the static frame and an optimal point of view is now out and about, in fully immersive mode within CAVEs. Art knowledge is a guide to how the aesthetics of 2D and 3D worlds affect, transform, and influence the social, intellectual and physical condition of the human body through attention to psychology, spiritual thinking, education, and cognition. The psychological interacts with the physical in the virtual in such a way that each facilitates, enhances and extends the other, culminating in a "go together" world. Attention to sharing art experience across high-speed networks introduces a dimension of liveliness and aliveness when we "become virtual" in real time with others.

  10. Contributions of low- and high-level properties to neural processing of visual scenes in the human brain.

    PubMed

    Groen, Iris I A; Silson, Edward H; Baker, Chris I

    2017-02-19

    Visual scene analysis in humans has been characterized by the presence of regions in extrastriate cortex that are selectively responsive to scenes compared with objects or faces. While these regions have often been interpreted as representing high-level properties of scenes (e.g. category), they also exhibit substantial sensitivity to low-level (e.g. spatial frequency) and mid-level (e.g. spatial layout) properties, and it is unclear how these disparate findings can be united in a single framework. In this opinion piece, we suggest that this problem can be resolved by questioning the utility of the classical low- to high-level framework of visual perception for scene processing, and discuss why low- and mid-level properties may be particularly diagnostic for the behavioural goals specific to scene perception as compared to object recognition. In particular, we highlight the contributions of low-level vision to scene representation by reviewing (i) retinotopic biases and receptive field properties of scene-selective regions and (ii) the temporal dynamics of scene perception that demonstrate overlap of low- and mid-level feature representations with those of scene category. We discuss the relevance of these findings for scene perception and suggest a more expansive framework for visual scene analysis.This article is part of the themed issue 'Auditory and visual scene analysis'.

  11. Sunflower (Helianthus annuus) long-chain acyl-coenzyme A synthetases expressed at high levels in developing seeds.

    PubMed

    Aznar-Moreno, Jose A; Venegas Calerón, Mónica; Martínez-Force, Enrique; Garcés, Rafael; Mullen, Robert; Gidda, Satinder K; Salas, Joaquín J

    2014-03-01

    Long chain fatty acid synthetases (LACSs) activate the fatty acid chains produced by plastidial de novo biosynthesis to generate acyl-CoA derivatives, important intermediates in lipid metabolism. Oilseeds, like sunflower, accumulate high levels of triacylglycerols (TAGs) in their seeds to nourish the embryo during germination. This requires that sunflower seed endosperm supports very active glycerolipid synthesis during development. Sunflower seed plastids produce large amounts of fatty acids, which must be activated through the action of LACSs, in order to be incorporated into TAGs. We cloned two different LACS genes from developing sunflower endosperm, HaLACS1 and HaLACS2, which displayed sequence homology with Arabidopsis LACS9 and LACS8 genes, respectively. These genes were expressed at high levels in developing seeds and exhibited distinct subcellular distributions. We generated constructs in which these proteins were fused to green fluorescent protein and performed transient expression experiments in tobacco cells. The HaLACS1 protein associated with the external envelope of tobacco chloroplasts, whereas HaLACS2 was strongly bound to the endoplasmic reticulum. Finally, both proteins were overexpressed in Escherichia coli and recovered as active enzymes in the bacterial membranes. Both enzymes displayed similar substrate specificities, with a very high preference for oleic acid and weaker activity toward stearic acid. On the basis of our findings, we discuss the role of these enzymes in sunflower oil synthesis.

  12. Rapid High-Level Production of Functional HIV Broadly Neutralizing Monoclonal Antibodies in Transient Plant Expression Systems

    PubMed Central

    Rosenberg, Yvonne; Sack, Markus; Montefiori, David; Forthal, Donald; Mao, Lingjun; -Abanto, Segundo Hernandez; Urban, Lori; Landucci, Gary; Fischer, Rainer; Jiang, Xiaoming

    2013-01-01

    Passive immunotherapy using anti-HIV broadly neutralizing monoclonal antibodies (mAbs) has shown promise as an HIV treatment, reducing mother-to-child-transmission (MTCT) of simian/human immunodeficiency virus (SHIV) in non-human primates and decreasing viral rebound in patients who ceased receiving anti-viral drugs. In addition, a cocktail of potent mAbs may be useful as mucosal microbicides and provide an effective therapy for post-exposure prophylaxis. However, even highly neutralizing HIV mAbs used today may lose their effectiveness if resistance occurs, requiring the rapid production of new or engineered mAbs on an ongoing basis in order to counteract the viral resistance or the spread of a certain HIV-1 clade in a particular region or patient. Plant-based expression systems are fast, inexpensive and scalable and are becoming increasingly popular for the production of proteins and monoclonal antibodies. In the present study, Agrobacterium-mediated transient transfection of plants, utilizing two species of Nicotiana, have been tested to rapidly produce high levels of an HIV 89.6PΔ140env and several well-studied anti-HIV neutralizing monoclonal antibodies (b12, 2G12, 2F5, 4E10, m43, VRC01) or a single chain antibody construct (m9), for evaluation in cell-based viral inhibition assays. The protein-A purified plant-derived antibodies were intact, efficiently bound HIV envelope, and were equivalent to, or in one case better than, their counterparts produced in mammalian CHO or HEK-293 cells in both neutralization and antibody dependent viral inhibition assays. These data indicate that transient plant-based transient expression systems are very adaptable and could rapidly generate high levels of newly identified functional recombinant HIV neutralizing antibodies when required. In addition, they warrant detailed cost-benefit analysis of prolonged incubation in plants to further increase mAb production. PMID:23533588

  13. Mechanisms of drug resistance: quinolone resistance

    PubMed Central

    Hooper, David C.; Jacoby, George A.

    2015-01-01

    Quinolone antimicrobials are synthetic and widely used in clinical medicine. Resistance emerged with clinical use and became common in some bacterial pathogens. Mechanisms of resistance include two categories of mutation and acquisition of resistance-conferring genes. Resistance mutations in one or both of the two drug target enzymes, DNA gyrase and DNA topoisomerase IV, are commonly in a localized domain of the GyrA and ParE subunits of the respective enzymes and reduce drug binding to the enzyme-DNA complex. Other resistance mutations occur in regulatory genes that control the expression of native efflux pumps localized in the bacterial membrane(s). These pumps have broad substrate profiles that include quinolones as well as other antimicrobials, disinfectants, and dyes. Mutations of both types can accumulate with selection pressure and produce highly resistant strains. Resistance genes acquired on plasmids can confer low-level resistance that promotes the selection of mutational high-level resistance. Plasmid-encoded resistance is due to Qnr proteins that protect the target enzymes from quinolone action, one mutant aminoglycoside-modifying enzyme that also modifies certain quinolones, and mobile efflux pumps. Plasmids with these mechanisms often encode additional antimicrobial resistances and can transfer multidrug resistance that includes quinolones. Thus, the bacterial quinolone resistance armamentarium is large. PMID:26190223

  14. Mechanisms of drug resistance: quinolone resistance.

    PubMed

    Hooper, David C; Jacoby, George A

    2015-09-01

    Quinolone antimicrobials are synthetic and widely used in clinical medicine. Resistance emerged with clinical use and became common in some bacterial pathogens. Mechanisms of resistance include two categories of mutation and acquisition of resistance-conferring genes. Resistance mutations in one or both of the two drug target enzymes, DNA gyrase and DNA topoisomerase IV, are commonly in a localized domain of the GyrA and ParE subunits of the respective enzymes and reduce drug binding to the enzyme-DNA complex. Other resistance mutations occur in regulatory genes that control the expression of native efflux pumps localized in the bacterial membrane(s). These pumps have broad substrate profiles that include quinolones as well as other antimicrobials, disinfectants, and dyes. Mutations of both types can accumulate with selection pressure and produce highly resistant strains. Resistance genes acquired on plasmids can confer low-level resistance that promotes the selection of mutational high-level resistance. Plasmid-encoded resistance is due to Qnr proteins that protect the target enzymes from quinolone action, one mutant aminoglycoside-modifying enzyme that also modifies certain quinolones, and mobile efflux pumps. Plasmids with these mechanisms often encode additional antimicrobial resistances and can transfer multidrug resistance that includes quinolones. Thus, the bacterial quinolone resistance armamentarium is large.

  15. Advanced waste form and Melter development for treatment of troublesome high-level wastes

    SciTech Connect

    Marra, James; Kim, Dong -Sang; Maio, Vincent

    2015-10-01

    A number of waste components in US defense high level radioactive wastes (HLW) have proven challenging for current Joule heated ceramic melter (JHCM) operations and have limited the ability to increase waste loadings beyond already realized levels. Many of these “troublesome" waste species cause crystallization in the glass melt that can negatively impact product quality or have a deleterious effect on melter processing. Recent efforts at US Department of Energy laboratories have focused on understanding crystallization behavior within HLW glass melts and investigating approaches to mitigate the impacts of crystallization so that increases in waste loading can be realized. Advanced glass formulations have been developed to highlight the unique benefits of next-generation melter technologies such as the Cold Crucible Induction Melter (CCIM). Crystal-tolerant HLW glasses have been investigated to allow sparingly soluble components such as chromium to crystallize in the melter but pass out of the melter before accumulating.The Hanford site AZ-101 tank waste composition represents a waste group that is waste loading limited primarily due to high concentrations of Fe2O3 (also with high Al2O3 concentrations). Systematic glass formulation development utilizing slightly higher process temperatures and higher tolerance to spinel crystals demonstrated that an increase in waste loading of more than 20% could be achieved for this waste composition, and by extension higher loadings for wastes in the same group. An extended duration CCIM melter test was conducted on an AZ-101 waste simulant using the CCIM platform at the Idaho National Laboratory (INL). The melter was continually operated for approximately 80 hours demonstrating that the AZ-101 high waste loading glass composition could be readily processed using the CCIM technology. The resulting glass was close to the targeted composition and exhibited excellent durability in both

  16. DEVELOPMENT OF AN IMPROVED SODIUM TITANATE FOR THE PRETREATMENT OF HIGH LEVEL NUCLEAR WASTE AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Hobbs, D

    2007-11-15

    High-level nuclear waste produced from fuel reprocessing operations at the Savannah River Site (SRS) requires pretreatment to remove Cs-137, Sr-90 and alpha-emitting radionuclides (i.e., actinides) prior to disposal onsite as low level waste. Separation processes planned at SRS include sorption of Sr-90 and alpha-emitting radionuclides onto monosodium titanate (MST) and caustic side solvent extraction, for {sup 137}Cs removal. The predominant alpha-emitting radionuclides in the highly alkaline waste solutions include plutonium isotopes Pu-238, Pu-239 and Pu-240. This paper describes recent results to produce an improved sodium titanate material that exhibits increased removal kinetics and capacity for Sr-90 and alpha-emitting radionuclides compared to the baseline MST material.

  17. DEVELOPMENT OF AN IMPROVED SODIUM TITANATE FOR THE PRETREATMENT OF HIGH LEVEL NUCLEAR WASTE AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Hobbs D. T.; Poirier, M. R.; Barnes, M. J.; Stallings, M. E.; Nyman, M. D.

    2005-11-22

    High-level nuclear waste produced from fuel reprocessing operations at the Savannah River Site (SRS) requires pretreatment to remove {sup 137}Cs, {sup 90}Sr and alpha-emitting radionuclides (i.e., actinides) prior to disposal onsite as low level waste. Separation processes planned at SRS include caustic side solvent extraction, for {sup 137}Cs removal, and sorption of {sup 90}Sr and alpha-emitting radionuclides onto monosodium titanate (MST). The predominant alpha-emitting radionuclides in the highly alkaline waste solutions include plutonium isotopes {sup 238}Pu, {sup 239}Pu and {sup 240}Pu. This paper describes recent results to produce an improved sodium titanate material that exhibits increased removal kinetics and capacity for {sup 90}Sr and alpha-emitting radionuclides compared to the baseline MST material.

  18. RESULTS OF THE FY09 ENHANCED DOE HIGH LEVEL WASTE MELTER THROUGHPUT STUDIES AT SRNL

    SciTech Connect

    Johnson, F.; Edwards, T.

    2010-06-23

    High-level waste (HLW) throughput (i.e., the amount of waste processed per unit time) is a function of two critical parameters: waste loading (WL) and melt rate. For the Waste Treatment and Immobilization Plant (WTP) at the Hanford Site and the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS), increasing HLW throughput would significantly reduce the overall mission life cycle costs for the Department of Energy (DOE). The objective of this task is to develop data, assess property models, and refine or develop the necessary models to support increased WL of HLW at SRS. It is a continuation of the studies initiated in FY07, but is under the specific guidance of a Task Change Request (TCR)/Work Authorization received from DOE headquarters (Project Number RV071301). Using the data generated in FY07, FY08 and historical data, two test matrices (60 glasses total) were developed at the Savannah River National Laboratory (SRNL) in order to generate data in broader compositional regions. These glasses were fabricated and characterized using chemical composition analysis, X-ray Diffraction (XRD), viscosity, liquidus temperature (TL) measurement and durability as defined by the Product Consistency Test (PCT). The results of this study are summarized below: (1) In general, the current durability model predicts the durabilities of higher waste loading glasses quite well. A few of the glasses exhibited poorer durability than predicted. (2) Some of the glasses exhibited anomalous behavior with respect to durability (normalized leachate for boron (NL [B])). The quenched samples of FY09EM21-02, -07 and -21 contained no nepheline or other wasteform affecting crystals, but have unacceptable NL [B] values (> 10 g/L). The ccc sample of FY09EM21-07 has a NL [B] value that is more than one half the value of the quenched sample. These glasses also have lower concentrations of Al{sub 2}O{sub 3} and SiO{sub 2}. (3) Five of the ccc samples (EM-13, -14, -15, -29 and

  19. High-Level Clonal FGFR Amplification and Response to FGFR Inhibition in a Translational Clinical Trial

    PubMed Central

    Babina, Irina S.; Herrera-Abreu, Maria Teresa; Tarazona, Noelia; Peckitt, Clare; Kilgour, Elaine; Smith, Neil R.; Geh, Catherine; Rooney, Claire; Cutts, Ros; Campbell, James; Ning, Jian; Fenwick, Kerry; Swain, Amanda; Brown, Gina; Chua, Sue; Thomas, Anne; Johnston, Stephen R.D.; Ajaz, Mazhar; Sumpter, Katherine; Gillbanks, Angela; Watkins, David; Chau, Ian; Popat, Sanjay; Cunningham, David; Turner, Nicholas C.

    2017-01-01

    FGFR1 and FGFR2 are amplified in many tumor types, yet what determines response to FGFR inhibition in amplified cancers is unknown. In a translational clinical trial, we show that gastric cancers with high-level clonal FGFR2 amplification have a high response rate to the selective FGFR inhibitor AZD4547, whereas cancers with subclonal or low-level amplification did not respond. Using cell lines and patient-derived xenograft models, we show that high-level FGFR2 amplification initiates a distinct oncogene addiction phenotype, characterized by FGFR2-mediated transactivation of alternative receptor kinases, bringing PI3K/mTOR signaling under FGFR control. Signaling in low-level FGFR1-amplified cancers is more restricted to MAPK signaling, limiting sensitivity to FGFR inhibition. Finally, we show that circulating tumor DNA screening can identify high-level clonally amplified cancers. Our data provide a mechanistic understanding of the distinct pattern of oncogene addiction seen in highly amplified cancers and demonstrate the importance of clonality in predicting response to targeted therapy. Significance Robust single-agent response to FGFR inhibition is seen only in high-level FGFR-amplified cancers, with copy-number level dictating response to FGFR inhibition in vitro, in vivo, and in the clinic. High-level amplification of FGFR2 is relatively rare in gastric and breast cancers, and we show that screening for amplification in circulating tumor DNA may present a viable strategy to screen patients. PMID:27179038

  20. The audit of the Replacement High Level Waste Evaporator at the Savannah River Site

    SciTech Connect

    1995-06-26

    The Savannah River Site (Site), owned by the Departmen Energy (Department) and managed by Westinghouse Savannah River Company (Westinghouse), recently changed its primary mission from producing nuclear materials to environmental restoration and waste management. A major focus in the Site`s mission is the storage, treatment, stabilization, and disposal of high level radioactive waste materials. To accomplish this mission, the Site will integrate its high level waste treatment facilities into a High Level Waste System (System), which will process the radioactive waste material in six distinct batches. An integral part of the System is the Replacement High Level Waste Evaporator (Replacement Evaporator) which will evaporate water added to the high level waste during processing, thereby minimizing the volume of the waste stream. Currently, the System has the evaporator and tank farm capacity to accommodate the processing of the first batch of radioactive waste, which is scheduled to begin in March 1996. However, the system will need the Replacement Evaporator to accommodate the volume of water and solvent added during processing of the second batch of radioactive waste scheduled to begin processing in 2004.

  1. Factors related to high-level mobility in male servicemembers with traumatic lower-limb loss.

    PubMed

    Gaunaurd, Ignacio A; Roach, Kathryn E; Raya, Michele A; Hooper, Rebecca; Linberg, Alison A; Laferrier, Justin Z; Campbell, Stuart M; Scoville, Charles; Gailey, Robert S

    2013-01-01

    The purpose of this study was to examine the possible relationship between factors modifiable by rehabilitation interventions (rehabilitation factors), other factors related to lower-limb loss (other factors), and high-level mobility as measured by the Comprehensive High-Level Activity Mobility Predictor (CHAMP) in servicemembers (SMs) with traumatic lower-limb loss. One-hundred eighteen male SMs with either unilateral transtibial amputation (TTA), unilateral transfemoral amputation (TFA), or bilateral lower-limb amputation (BLLA) participated. Stepwise regression analysis was used to develop separate regression models of factors predicting CHAMP score. Regression models containing both rehabilitation factors and other factors explained 81% (TTA), 36% (TFA), and 91% (BLLA) of the variance in CHAMP score. Rehabilitation factors such as lower-limb strength and dynamic balance were found to be significantly related to CHAMP score and can be enhanced with the appropriate intervention. Further, the findings support the importance of salvaging the knee joint and its effect on high-level mobility capabilities. Lastly, the J-shaped energy storage and return feet were found to improve high-level mobility for SMs with TTA. These results could help guide rehabilitation and aid in developing appropriate interventions to assist in maximizing high-level mobility capabilities for SMs with traumatic lower-limb loss.

  2. Extending Automatic Parallelization to Optimize High-Level Abstractions for Multicore

    SciTech Connect

    Liao, C; Quinlan, D J; Willcock, J J; Panas, T

    2008-12-12

    Automatic introduction of OpenMP for sequential applications has attracted significant attention recently because of the proliferation of multicore processors and the simplicity of using OpenMP to express parallelism for shared-memory systems. However, most previous research has only focused on C and Fortran applications operating on primitive data types. C++ applications using high-level abstractions, such as STL containers and complex user-defined types, are largely ignored due to the lack of research compilers that are readily able to recognize high-level object-oriented abstractions and leverage their associated semantics. In this paper, we automatically parallelize C++ applications using ROSE, a multiple-language source-to-source compiler infrastructure which preserves the high-level abstractions and gives us access to their semantics. Several representative parallelization candidate kernels are used to explore semantic-aware parallelization strategies for high-level abstractions, combined with extended compiler analyses. Those kernels include an array-base computation loop, a loop with task-level parallelism, and a domain-specific tree traversal. Our work extends the applicability of automatic parallelization to modern applications using high-level abstractions and exposes more opportunities to take advantage of multicore processors.

  3. Comparative Genomics Study of Multi-Drug-Resistance Mechanisms in the Antibiotic-Resistant Streptococcus suis R61 Strain

    PubMed Central

    Zhang, Anding; Wu, Jiayan; Chen, Bo; Hua, Yafeng; Yu, Jun; Chen, Huanchun; Xiao, Jingfa; Jin, Meilin

    2011-01-01

    Background Streptococcus suis infections are a serious problem for both humans and pigs worldwide. The emergence and increasing prevalence of antibiotic-resistant S. suis strains pose significant clinical and societal challenges. Results In our study, we sequenced one multi-drug-resistant S. suis strain, R61, and one S. suis strain, A7, which is fully sensitive to all tested antibiotics. Comparative genomic analysis revealed that the R61 strain is phylogenetically distinct from other S. suis strains, and the genome of R61 exhibits extreme levels of evolutionary plasticity with high levels of gene gain and loss. Our results indicate that the multi-drug-resistant strain R61 has evolved three main categories of resistance. Conclusions Comparative genomic analysis of S. suis strains with diverse drug-resistant phenotypes provided evidence that horizontal gene transfer is an important evolutionary force in shaping the genome of multi-drug-resistant strain R61. In this study, we discovered novel and previously unexamined mutations that are strong candidates for conferring drug resistance. We believe that these mutations will provide crucial clues for designing new drugs against this pathogen. In addition, our work provides a clear demonstration that the use of drugs has driven the emergence of the multi-drug-resistant strain R61. PMID:21966396

  4. Spirotetramat Resistance Selected in the Phenacoccus solenopsis (Homoptera: Pseudococcidae): Cross-Resistance Patterns, Stability, and Fitness Costs Analysis.

    PubMed

    Ejaz, Masood; Ali Shad, Sarfraz

    2017-03-02

    The Phenacoccus solenopsis Tinsley (Homoptera: Pseudococcidae) is a major agricultural and horticultural pest of crops throughout the world. To develop a better resistance management strategy for P. solenopsis, we conducted a study on life history parameters of different populations of this pest, one selected with spirotetramat (Spiro-SEL), an unselected (UNSEL) population, and their reciprocal crosses. We also studied the cross-resistance and the stability of spirotetramat resistance. The Spiro-SEL of P. solenopsis exhibited a 328.69-fold resistance compared to the susceptible population (Lab-PK). The Spiro-SEL population also displayed a moderate level of cross-resistance to profenofos and bifenthrin and a high level of cross-resistance to abamectin. Resistance to spirotetramat in Spiro-SEL was unstable in the absence of selection. The study of life history parameters showed that there was a significant reduction in fitness parameters of Spiro-SEL population with a relative fitness value of 0.14. There was a significant decrease in survival rate, pupal weight, fecundity, egg hatching percentage, male and female generation time, intrinsic rate of population increase of males and females, biotic potential, and mean relative growth rate. It is concluded that selection with spirotetramat had marked effect on resistance development in P. solenopsis and upon removal of selection pressure spirotetramat resistance declined significantly, indicating unstable resistance. Development of resistance led to high fitness costs for the spirotetramat-selected population. Our study may provide the basic information on spirotetramat resistance and its mechanism to help develop the resistance management strategies.

  5. Antibiotic resistance among cultured bacterial isolates from bioethanol fermentation facilities across the United States.

    PubMed

    Murphree, Colin A; Heist, E Patrick; Moe, Luke A

    2014-09-01

    Bacterial contamination of fuel ethanol fermentations by lactic acid bacteria (LAB) can have crippling effects on bioethanol production. Producers have had success controlling bacterial growth through prophylactic addition of antibiotics to fermentors, yet concerns have arisen about antibiotic resistance among the LAB. Here, we report on mechanisms used by 32 LAB isolates from eight different US bioethanol facilities to persist under conditions of antibiotic stress. Minimum inhibitory concentration assays with penicillin, erythromycin, and virginiamycin revealed broad resistance to each of the antibiotics as well as high levels of resistance to individual antibiotics. Phenotypic assays revealed that antibiotic inactivation mechanisms contributed to the high levels of individual resistances among the isolates, especially to erythromycin and virginiamycin, yet none of the isolates appeared to use a β-lactamase. Biofilm formation was noted among the majority of the isolates and may contribute to persistence under low levels of antibiotics. Nearly all of the isolates carried at least one canonical antibiotic resistance gene and many carried more than one. The erythromycin ribosomal methyltransferase (erm) gene class was found in 19 of 32 isolates, yet a number of these isolates exhibit little to no resistance to erythromycin. The erm genes were present in 15 isolates that encoded more than one antibiotic resistance mechanism, suggestive of potential genetic linkages.

  6. Heat transfer analysis of the geologic disposal of spent fuel and high level waste storage canisters

    NASA Astrophysics Data System (ADS)

    Allen, G. K.

    1980-08-01

    Near-field temperatures resulting from the storage of high-level waste canisters and spent unreprocessed fuel assembly canisters in geologic formations were determined. Preliminary design of the repository was modeled for a heat transfer computer code, HEATING5, which used the finite difference method to evaluate transient heat transfer. The heat transfer system was evaluated with several two and three dimensional models which transfer heat by a combination of conduction, natural convention, and radiation. Physical properties of the materials in the model were based upon experimental values for the various geologic formations. The effects of canister spacing, fuel age, and use of an overpack were studied for the analysis of the spent fuel canisters; salt, granite, and basalt were considered as the storage media. The effects of canister diameter and use of an overpack were studied for the analysis of the high-level waste canisters; salt was considered as the only storage media for high-level waste canisters.

  7. High-level waste processing at the Savannah River Site: An update

    SciTech Connect

    Marra, J.E.; Bennett, W.M.; Elder, H.H.; Lee, E.D.; Marra, S.L.; Rutland, P.L.

    1997-09-01

    The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) in Aiken, SC mg began immobilizing high-level radioactive waste in borosilicate glass in 1996. Currently, the radioactive glass is being produced as a ``sludge-only`` composition by combining washed high-level waste sludge with glass frit. The glass is poured in stainless steel canisters which will eventually be disposed of in a permanent, geological repository. To date, DWPF has produced about 100 canisters of vitrified waste. Future processing operations will, be based on a ``coupled`` feed of washed high-level waste sludge, precipitated cesium, and glass frit. This paper provides an update of the processing activities completed to date, operational/flowsheet problems encountered, and programs underway to increase production rates.

  8. Predictors of High Level of Hostility among Homeless Men on Parole.

    PubMed

    Nyamathi, Adeline; Salem, Benissa; Farabee, David; Hall, Elizabeth; Zhang, Sheldon; Khalilifard, Farinaz; Faucette, Mark; Leake, Barbara

    2014-02-01

    High levels of hostility present a formidable challenge among homeless ex-offenders. This cross-sectional study assessed correlates of high levels of hostility using baseline data collected on recently-released male parolees (N=472; age 18-60) participating in a randomized trial focused on prevention of illicit drug use and recidivism. Predictors of high levels of hostility included greater depressive symptomatology, lower self-esteem, having a mother who was treated for alcohol/drugs, belonging to a gang, more tangible support, having used methamphetamine and having a history of cognitive difficulties. These findings highlight the need to understand predictors of hostility among recently released homeless men and how these predictors may relate to recidivism. Research implications are discussed as these findings will shape future nurse-led harm reduction and community-based interventions.

  9. Determination of total cyanide in Hanford Site high-level wastes

    SciTech Connect

    Winters, W.I.; Pool, K.H.

    1994-05-01

    Nickel ferrocyanide compounds (Na{sub 2-x}Cs{sub x}NiFe (CN){sub 6}) were produced in a scavenging process to remove {sup 137}Cs from Hanford Site single-shell tank waste supernates. Methods for determining total cyanide in Hanford Site high-level wastes are needed for the evaluation of potential exothermic reactions between cyanide and oxidizers such as nitrate and for safe storage, processing, and management of the wastes in compliance with regulatory requirements. Hanford Site laboratory experience in determining cyanide in high-level wastes is summarized. Modifications were made to standard cyanide methods to permit improved handling of high-level waste samples and to eliminate interferences found in Hanford Site waste matrices. Interferences and associated procedure modifications caused by high nitrates/nitrite concentrations, insoluble nickel ferrocyanides, and organic complexants are described.

  10. Antibiotic resistance among aquatic bacteria in natural freshwater environments of Korea.

    PubMed

    Kim, Tae Woon; Joung, Yochan; Han, Ji-Hye; Jung, Wonwha; Kim, Seung Bum

    2015-12-01

    The taxonomic diversity and antibiotic resistance among freshwater bacterial communities in the major water bodies of Korea was examined using 437 penicillin-resistant, and 110 tetracycline-resistant bacterial isolates. Based on 16S rRNA gene sequence analysis, most isolates were assigned to Proteobacteria, which was then followed by Bacteroidetes. Strains of Aeromonas were found as the most abundant penicillin-resistant populations, whereas those affiliated to diverse species including enteric groups were found as the most abundant tetracycline-resistant populations. Most strains exhibited multiple antibiotic resistance, and all tested strains were resistant<