Synthesis and novel fluorescence phenomenon of terbium(III) complex with N, N',N' -tris (2-benzimidazolmethyl) amine

International Nuclear Information System (INIS)

Yang, Tianlin; Gao, Min; Yang, Jinhui; Qin, Wenwu

2010-01-01

A benzimidazole ligand with a tripodal structure, N, N', N' -tris (2-benzimidazolmethyl) amine, and its terbium (III) complex has been synthesized. The complex has been characterized by element analysis, IR spectra, mass spectra, thermal analysis and molar conductivity. The terbium ion is found to coordinate with the nitrogen atoms (= N-) of imidazole ring and the bridgehead nitrogen atom. The fluorescence properties of the complex in aqueous solutions have been studied. Under excitation of UV light, the complex exhibits characteristic fluorescence of terbium ion. The luminescence of terbium complex in aqueous solutions is strongly enhanced by H + concentration. This phenomenon makes the new complex favorable for use in fluorescence switches and sensors. The mechanism of the fluorescence enhancement by protonation of the nitrogen atoms (-NH-) of imidazole ring is due to the suppressed photoinduced electron transfer fluorescence quenching on addition of acid. (author)

Nuclear magnetic resonance in ferromagnetic terbium metal

International Nuclear Information System (INIS)

Cha, C.L.T.

1974-01-01

The magnetic properties of terbium were studied by the method of zero field nuclear magnetic resonance at 1.5 to 4 and 85 to 160 0 K. Two unconventional experimental techniques have been employed: the swept frequency and the swept temperature technique. Near 4 0 K, triplet resonance line structures were found and interpreted in terms of the magnetic domain and wall structures of ferromagnetic terbium. In the higher temperature range, temperature dependence of the resonance frequency and the quadrupole splitting were measured. The former provides a measurement of the temperature dependence of the magnetization M, and it agrees with bulk M measurements as well as the latest spin wave theory of M(T) (Brooks 1968). The latter agrees well with a calculation using a very general single ion density matrix for collective excitations (Callen and Shtrikman 1965). In addition, the small temperature-independent contribution to the electric field gradient at the nucleus due to the lattice and conduction electrons was untangled from the P(T) data. Also an anomalous and unexplained relaxation phenomenon was also observed

Terbium nitrate luminescence quenching by eosin in he presence of lithium perchlorate in sulfolane solutions

International Nuclear Information System (INIS)

Ostakhov, S.S.; Kolosnitsyn, V.S.; Krasnogorskaya, N.N.; Kazakov, V.P.

2000-01-01

Quenching of terbium nitrate luminescence by anionic dye, eosin, in the presence of lithium perchlorate in sulfolane solutions was studied. Temperature dependence of terbium nitrate luminescence in sulfolane solutions in the presence of perchlorate anions were considered. The values of energy required for water molecular substitution in Tb 3+ ion coordination sphere for solvent molecule in electrolyte solution were ascertained [ru

Semiconductor composition containing iron, dysprosium, and terbium

Science.gov (United States)

Pooser, Raphael C.; Lawrie, Benjamin J.; Baddorf, Arthur P.; Malasi, Abhinav; Taz, Humaira; Farah, Annettee E.; Kalyanaraman, Ramakrishnan; Duscher, Gerd Josef Mansfred; Patel, Maulik K.

2017-09-26

An amorphous semiconductor composition includes 1 to 70 atomic percent iron, 15 to 65 atomic percent dysprosium, 15 to 35 atomic percent terbium, balance X, wherein X is at least one of an oxidizing element and a reducing element. The composition has an essentially amorphous microstructure, an optical transmittance of at least 50% in at least the visible spectrum and semiconductor electrical properties.

Low-temperature thermal conductivity of terbium-gallium garnet

International Nuclear Information System (INIS)

Inyushkin, A. V.; Taldenkov, A. N.

2010-01-01

Thermal conductivity of paramagnetic Tb 3 Ga 5 O 12 (TbGG) terbium-gallium garnet single crystals is investigated at temperatures from 0.4 to 300 K in magnetic fields up to 3.25 T. A minimum is observed in the temperature dependence κ(T) of thermal conductivity at T min = 0.52 K. This and other singularities on the κ(T) dependence are associated with scattering of phonons from terbium ions. The thermal conductivity at T = 5.1 K strongly depends on the magnetic field direction relative to the crystallographic axes of the crystal. Experimental data are considered using the Debye theory of thermal conductivity taking into account resonance scattering of phonons from Tb 3+ ions. Analysis of the temperature and field dependences of the thermal conductivity indicates the existence of a strong spin-phonon interaction in TbGG. The low-temperature behavior of the thermal conductivity (field and angular dependences) is mainly determined by resonance scattering of phonons at the first quasi-doublet of the electron spectrum of Tb 3+ ion.

Automated spectrofluorimetric determinations of terbium and dysprosium in rare earth mixtures

Energy Technology Data Exchange (ETDEWEB)

Lyle, S.J.; Za' tar, N. (Kent Univ., Canterbury (UK))

1983-12-01

Several methods involving the use of water-soluble binary and ternary complexes have been proposed for the spectrofluorimetric determination based on terbium(III) emission at 545 nm. These are terbium(III) with (A) ethylenediamine-N,N'-bis(o-hydroxyphenylacetic acid), (B) o-hydroxyphenyliminodiacetic acid, (C) EDTA + 5-sulphosalicylic acid, (D) EDTA + 1,2-dihydroxybenzene-3,5-disulphonic acid disodium salt (Tiron), and (E) iminodiacetic acid (IDA) + Tiron. Two of the reagent mixtures (D and E) can also be used for the fluorimetric determination of dysprosium(III) at 582 nm. A comparison has been made of these methods in order to select the most satisfactory procedure with respect to selectivity, sensitivity and suitability for adaption to automatic operation. Results are given and discussed.

Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

Energy Technology Data Exchange (ETDEWEB)

Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K. (Abbott Laboratories, Department 90M, Abbott Park, IL (United States))

1991-01-01

Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.

Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

International Nuclear Information System (INIS)

Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K.

1991-01-01

Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates

X-ray fluorescence analysis of terbium oxide for rare earth impurities

International Nuclear Information System (INIS)

Chandola, L.C.; Machado, I.J.; Mohile, A.N.

1975-01-01

A method for the determination of Sm 2 O 3 , Eu 2 O 3 , Gd 2 O 3 , Dy 2 O 3 , Ho 2 O 3 and Y 2 O 3 in terbium oxide is described. The sample is converted to terbium oxalate, mixed with boric acid binder in the ratio 2:1, pelleted at a pressure of 20 tons over a boric acid backing pellet and irradiated with x-rays from a tungsten tube operated by Philips PW 1140 generator. The secondary x-rays thus generated are analysed by a LiF (200) crystal in Philips PW 1220 x-ray fluorescence spectrometer using suitable detectors. The minimum determination limit (MDL) is 0.01% for all rare earth oxides determined except for Y 2 O 3 for which it is 0.005%. (author)

Investigation of terbium scandate as an alternative gate dielectric in fully depleted transistors

Science.gov (United States)

Roeckerath, M.; Lopes, J. M. J.; Özben, E. Durǧun; Urban, C.; Schubert, J.; Mantl, S.; Jia, Y.; Schlom, D. G.

2010-01-01

Terbium scandate thin films were deposited by e-gun evaporation on (100) silicon substrates. Rutherford backscattering spectrometry and x-ray diffraction studies revealed homogeneous chemical compositions of the films. A dielectric constant of 26 and CV-curves with small hystereses were measured as well as low leakage current densities of <1 nA/cm2. Fully depleted n-type field-effect transistors on thin silicon-on-insulator substrates with terbium scandate gate dielectrics were fabricated with a gate-last process. The devices show inverse subthreshold slopes of 80 mV/dec and a carrier mobility for electrons of 225 cm2/V•s was extracted.

Magneto-optical studies of valence instability in europium and terbium phosphors

Czech Academy of Sciences Publication Activity Database

Rodrigues, L.C.v.; Hölsä, J.; Brito, H.F.; Maryško, Miroslav; Matos, J.R.; Paturi, P.; Rodrigues, R.V.; Lastusaari, M.

2016-01-01

Roč. 170, Feb (2016), 701-706 ISSN 0022-2313 Institutional support: RVO:68378271 Keywords : valence * europium * terbium * oxysulfide and -sulfate * phosphors * paramagnetic susceptibility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.686, year: 2016

Cross sections from 800 MeV proton irradiation of terbium

Energy Technology Data Exchange (ETDEWEB)

Engle, J.W., E-mail: jwengle@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mashnik, S.G.; Bach, H.; Couture, A.; Jackman, K.; Gritzo, R.; Ballard, B.D.; Fassbender, M.; Smith, D.M.; Bitteker, L.J.; Ullmann, J.L.; Gulley, M.S.; Pillai, C.; John, K.D.; Birnbaum, E.R. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Nortier, F.M., E-mail: meiring@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2012-11-02

Terbium foils were irradiated with 800 MeV protons to ascertain the potential for production of lanthanide isotopes of interest in medical, astrophysical, and basic science research and to contribute to nuclear data repositories. Isotopes produced in the foil were quantified by gamma spectroscopy. Cross sections for 35 isotopes produced in the irradiation are reported and compared with predictions by the MCNP6 transport code using the CEM03.03, Bertini and INCL + ABLA event generators. Our results indicate the need to accurately consider fission and fragmentation of relatively light target nuclei like terbium in the modeling of nuclear reactions at 800 MeV. The predictive power of the code was found to be different for each event generator tested but was satisfactory for most of the product yields in the mass region where spallation reactions dominate. However, none of the event generators' results are in complete agreement with measured data.

Interaction of terbium group metal oxides with carbon

International Nuclear Information System (INIS)

Vodop'yanov, A.G.; Baranov, S.V.; Kozhevnikov, G.N.

1990-01-01

Mechanism of carbothermal reduction of terbium group metals from oxides is investigated using thermodynamic and kinetic analyses. Interaction of metal oxides with carbon covers dissociation of metal oxides and reduction by carbon monoxide, which contribution into general reduction depends on CO pressure. Temperatures of reaction beginning for batch initial components at P=1.3x10 -4 and P CO =0.1 MPa and of formation of oxycarbide melts are determined

Terbium oxide at high pressures

International Nuclear Information System (INIS)

Dogra, Sugandha; Sharma, Nita Dilawar; Singh, Jasveer; Bandhyopadhyay, A.K.

2011-01-01

In this work we report the behaviour of terbium oxide at high pressures. The as received sample was characterized at ambient by X-ray diffraction and Raman spectroscopy. The X-ray diffraction showed the sample to be predominantly cubic Tb 4 O 7 , although a few peaks also match closely with Tb 2 O 3 . In fact in a recent study done on the same sample, the sample has been shown to be a mixture of Tb 4 O 7 and Tb 2 O 3 . The sample was subjected to high pressures using a Mao-Bell type diamond anvil cell upto a pressure of about 42 GPa with ruby as pressure monitor

Terbium(III) ions as sensitizers of oxidation of indole and its derivatives in Fenton system

Energy Technology Data Exchange (ETDEWEB)

Kaczmarek, Małgorzata, E-mail: mkaczmar@amu.edu.pl; Staninski, Krzysztof

2017-03-15

Oxidation of indole and its derivatives in the Fenton system as a source of oxidising agents, in the presence of terbium(III) ions was studied by chemiluminescence methods to get the kinetic curves of emission decay and spectral distributions of chemiluminescence. Terbium(III) ions acted as a sensitizer of the mixtures Tb(III)-Fe(II)/Fe(III)-H{sub 2}O{sub 2}-indole or its derivative (tryptophan, tryptamine, indole-3-acetic acid and indole-3-acetyl aspartic acid). For the above indolic compounds, linear dependencies of integrated intensity of chemiluminescence on concentration of indolic compound in water and in water-acetonitrile solution were obtained. The limits of detection (LOD) and quantification (LOQ) of the indolic compounds studied were found to be by one or two orders of magnitude lower in the system with terbium(III) ions than without them. - Highlights: • Chemiluminescence emitted on oxidation of indolic compounds in Fenton system. • Tb (III) ions as sensitizers of indolic compounds oxidation in solutions. • Linear relations between CL intensity and indolic compound concentration.

Complex compounds of terbium(III) with some nonsteroidal anti-inflammatory drugs and their analytical applications

International Nuclear Information System (INIS)

Teslyuk, O.I.; Egorova, A.V.; Yagodkin, B.N.; Bel'tyukova, S.V.

2007-01-01

Luminescence properties of the complexes of terbium(III) with nonsteroidal anti-inflammatory drugs (ibuprofen and orthofen) were studied. It was demonstrated that in the presence of organic bases (2,2'-dipyridyl and 1,10-phenanthroline) mixed-ligand complexes are formed and the luminescence intensity of terbium(III) increases by a factor of up to 250. The optimum complexation conditions were determined. It was proposed to use these complexes as analytical forms for the luminescence determination of nonsteroidal anti-inflammatory drugs (ibuprofen and orthofen) in pharmaceutical dosage forms. The detection limits are 2 and 0.05 μg/ml, respectively [ru

Green light emission in aluminum oxide powders doped with different terbium concentrations

Energy Technology Data Exchange (ETDEWEB)

Mariscal B, L; Falcony, C. [IPN, Centro de Investigacion y de Estudios Avanzados, 07360 Ciudad de Mexico (Mexico); Carmona T, S.; Murrieta, H.; Sanchez A, M. A. [UNAM, Instituto de Fisica, 04510 Ciudad de Mexico (Mexico); Vazquez A, R. [IPN, Escuela Superior de Computo, 07738 Ciudad de Mexico (Mexico); Garcia R, C. M., E-mail: mariscal2005@gmail.com [UNAM, Facultad de Ciencias, 04510 Ciudad de Mexico (Mexico)

2016-11-01

Different emission intensities presented in aluminum oxide phosphors corresponding to different concentrations of doping performed with terbium are analyzed. The phosphors were synthesized by the evaporation technique and were characterized by photo and cathodoluminescence, X-ray diffraction and EDS techniques for different incorporation percentages of terbium as dopant; they show characteristic transitions in 494, 543, 587 and 622 nm, corresponding to {sup 5}D{sub 4} → {sup 7}F{sub 6}, {sup 5}D{sub 4} → {sup 7}F{sub 5}, {sup 5}D{sub 4} → {sup 7}F{sub 4} and {sup 5}D{sub 4} → {sup 7}F{sub 3}, respectively when they are excited with λ{sub exc} = 380 nm wavelength at room temperature. The results of X-ray diffraction show the presence of α-Al{sub 2}O{sub 3} phases with peaks located at 2θ = 25.78, 35.34, 37.96, 43.56, 45.8, 52.74, 57.7, 61.5, 66.74, 68.44, 77.12 and 80.94, and the δ-Al{sub 2}O-3 phase 2θ = 32.82, 45.8, 61.36 and 66.74. These compounds were heat treated for two hours at 1100 degrees Celsius. EDS analyzes indicate that these compounds have close to 60% oxygen around of 40% aluminum in the presence of terbium as dopant which indicates a stoichiometry close to the expected one for alumina. (Author)

Electroanalytical performance of a terbium(III)-selective sensor based on a neutral ionophore in environmental and medicinal samples

Energy Technology Data Exchange (ETDEWEB)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha [Indian Institute of Technology-Roorkee, Department of Chemistry, Roorkee (India)

2008-04-15

A new highly selective terbium(III) electrode was prepared with a polymeric film doped using S-2-benzothiazolyl-2-amino-{alpha}-(methoxyimino)-4-thiazolethiol acetate as an electroactive material, benzyl acetate (BA) as a plasticizer, and potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic site in the percentage ratio 3.17:1.58:63.4:31.7 (ionophore-KTpClPB-BA-PVC, w/w). The electrode exhibited a linear response with a near Nernstian slope of 19.5 mV/decade within the concentration range 1.5 x 10{sup -7}-1.0 x 10{sup -2} M terbium ions, with a working pH range from 2.0 to 8.0, and a fast response time of 10 s and presented satisfactory reproducibility. The limit of detection was 9.3 x 10{sup -8} M. The results show that this electrode can be used in ethanol media up to 30% (v/v) concentration without interference. It can be used for 3 months without any considerable divergence in the potentials. Selectivity coefficients for terbium(III) with respect to many cations were investigated. The electrode is highly selective for terbium(III) ions over a large number of monovalent, bivalent, and trivalent cations. This shows the valuable property of the proposed electrode. The stability constant of the ionophore towards Tb{sup 3+} ions was determined with the sandwich membrane method. It was successfully used as an indicator electrode in potentiometric determination of terbium(III) ions with EDTA and in direct determination in tap water and binary mixtures with quantitative results. The utility of the proposed electrode was also determined in the presence of ionic and nonionic surfactants and in the presence of fluoride ions in four pharmaceutical (mouthwash) preparations. (orig.)

Electroanalytical performance of a terbium(III)-selective sensor based on a neutral ionophore in environmental and medicinal samples

International Nuclear Information System (INIS)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha

2008-01-01

A new highly selective terbium(III) electrode was prepared with a polymeric film doped using S-2-benzothiazolyl-2-amino-α-(methoxyimino)-4-thiazolethiol acetate as an electroactive material, benzyl acetate (BA) as a plasticizer, and potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic site in the percentage ratio 3.17:1.58:63.4:31.7 (ionophore-KTpClPB-BA-PVC, w/w). The electrode exhibited a linear response with a near Nernstian slope of 19.5 mV/decade within the concentration range 1.5 x 10 -7 -1.0 x 10 -2 M terbium ions, with a working pH range from 2.0 to 8.0, and a fast response time of 10 s and presented satisfactory reproducibility. The limit of detection was 9.3 x 10 -8 M. The results show that this electrode can be used in ethanol media up to 30% (v/v) concentration without interference. It can be used for 3 months without any considerable divergence in the potentials. Selectivity coefficients for terbium(III) with respect to many cations were investigated. The electrode is highly selective for terbium(III) ions over a large number of monovalent, bivalent, and trivalent cations. This shows the valuable property of the proposed electrode. The stability constant of the ionophore towards Tb 3+ ions was determined with the sandwich membrane method. It was successfully used as an indicator electrode in potentiometric determination of terbium(III) ions with EDTA and in direct determination in tap water and binary mixtures with quantitative results. The utility of the proposed electrode was also determined in the presence of ionic and nonionic surfactants and in the presence of fluoride ions in four pharmaceutical (mouthwash) preparations. (orig.)

A terbium(III)-organic framework for highly selective sensing of cytidine triphosphate.

Science.gov (United States)

Zhao, Xi Juan; He, Rong Xing; Li, Yuan Fang

2012-11-21

Highly selective sensing of cytidine triphosphate (CTP) against other triphosphate nucleosides including ATP, GTP and UTP is successfully achieved with a luminescent terbium(III)-organic framework (TbOF) of [Tb(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)](n) (2,3-pzdc(2-) = 2,3-pyrazinedicarboxylate, ox(2-) = oxalate).

Raman spectra of terbium trichloride, phosphorus pentachloride and their molten mixtures

International Nuclear Information System (INIS)

Salyulev, A.B.; Zakir'yanova, I.D.

2008-01-01

Raman spectroscopy was used to study in situ the behavior of individual terbium trichloride and phosphorus pentachloride in different aggregative states as a function of temperature, and of solutions of PCl 5 vapors in molten TbCl 3 . A conclusion is drawn about their structure and the nature of phase transformations and chemical reactions in wide ranges of temperature and saturated vapor pressures [ru

Efficient green luminescence of terbium oxalate crystals: A case study with Judd-Ofelt theory and single crystal structure analysis and the effect of dehydration on luminescence

Science.gov (United States)

Alexander, Dinu; Joy, Monu; Thomas, Kukku; Sisira, S.; Biju, P. R.; Unnikrishnan, N. V.; Sudarsanakumar, C.; Ittyachen, M. A.; Joseph, Cyriac

2018-06-01

Design and synthesis of Lanthanide based metal organic framework is a frontier area of research owing to their structural diversity enabling specific applications. The luminescence properties of rare earths, tuned by the structural features of Ln-MOFs are investigated extensively. Rare earth oxalates which can be synthesized in a facile method, ensuring the structural features of MOFs with excellent photoluminescence characteristics deserves much attention. This work is the first time report on the single crystal structure and Judd-Ofelt (JO) theoretical analysis - their correlation with the intense and sharp green luminescence of Terbium oxalate crystals. The intense green luminescence observed for Terbium oxalate crystals for a wide range of excitation from DUV to visible region despite the luminescence limiting factors are discussed. The absence of concentration quenching and lifting up of forbidden nature of f-f transitions, allowing direct excitation of Terbium ions is analysed with the help of JO theory and single crystal structure analysis. The JO analysis predicted the asymmetry of Terbium sites, allowing the electric dipole transitions and from the JO intensity parameters, promising spectroscopic parameters - emission cross section, branching ratio, gain band width and gain coefficient of the material were calculated. The single crystal structure analysis revealed the asymmetry of Tb sites and structure of Terbium oxalate is formed by the hydrogen bonded stacking of overlapped six Terbium membered rings connected by the oxalate ligands. The molecularly thick layers thus formed on the crystal surface are imaged by the atomic force microscopy. The presence of water channels in the structure and the effect of lattice water molecules on the luminescence intensity are also investigated.

Spectrofluorimetric determination of cefixime using terbium-danofloxacin probe

Directory of Open Access Journals (Sweden)

Jamshid L Manzoori

2014-04-01

Full Text Available Objective(s:Cefixime (Cfx, is a semi-synthetic third-generation oral cephalosporin antibiotic that is prescribed for the treatment of susceptible infections. There are some procedures for the determination of Cfx in pharmaceutical formulations and biological samples. Herein a spectrofluorimetric method was proposed for Cfx determination based on the fluorescence quenching of terbium-danofloxacin (Tb3+-Dano in the presence of Cfx. Materials and Methods: Cfx was detected based on fluorescence quenching of terbium-danofloxacin (Tb3+-Dano in the presence of Cfx with maximum excitation and emission wavelengths at 347 nm and 545 nm, respectively. The quenched fluorescence intensity of Tb3+- Dano system is proportional to the concentration of Cfx. The optimum conditions for the determination of Cfx were studied. Results: The maximum response was achieved under optimum conditions of [Tris buffer]= 0.008 mol/l (pH 6.5, [Tb3+]=1×10-4 mol/l  and [Dano]=1×10-4 mol/l. The developed method was evaluated in terms of accuracy, precision and limit of detection. The linear concentration ranges for quantification of Cfx were 8.8×10-8-8.8×10-7 mol/l and 1.1×10-7-8.8×10-7 mol/l in standard and human serum samples with the detection limits (S/N=3 of 2.8×10-8 mol/l and 3.9×10-8 mol/l, respectively. The Cfx was determined in pharmaceutical tablets and spiked serum samples and the results were satisfactory.   Conclusion: This method is simple, practical and relatively interference-free for determination of Cfx in pharmaceutical tablets and serum samples.

Determination of fluoxetine in pharmaceutical and biological samples based on the silver nanoparticle enhanced fluorescence of fluoxetine-terbium complex.

Science.gov (United States)

Lotfi, Ali; Manzoori, Jamshid L

2016-11-01

In this study, a simple and sensitive spectrofluorimetric method is presented for the determination of fluoxetine based on the enhancing effect of silver nanoparticles (AgNPs) on the terbium-fluoxetine fluorescence emission. The AgNPs were prepared by a simple reduction method and characterized by UV-Vis spectroscopy and transmission electron microscopy. It was indicated that these AgNPs have a remarkable amplifying effect on the terbium-sensitized fluorescence of fluoxetine. The effects of various parameters such as AgNP and Tb 3+ concentration and the pH of the media were investigated. Under obtained optimal conditions, the fluorescence intensity of the terbium-fluoxetine-AgNP system was enhanced linearly by increasing the concentration of fluoxetine in the range of 0.008 to 19 mg/L. The limit of detection (b + 3s) was 8.3 × 10 -4 mg/L. The interference effects of common species found in real samples were also studied. The method had good linearity, recovery, reproducibility and sensitivity, and was satisfactorily applied for the determination of fluoxetine in tablet formulations, human urine and plasma samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Determination of fluoroquinolone antibiotics by microchip capillary electrophoresis along with time-resolved sensitized luminescence of their terbium(III) complexes

International Nuclear Information System (INIS)

Sierra-Rodero, Marina; Fernández -Romero, Juan Manuel; Gómez -Hens, Agustina

2014-01-01

We report on the time-resolved detection of the three fluoroquinolone (FQs) antibiotics ciprofloxacin (CIP), enrofloxacin (ENR) and flumequine (FLU). On addition of terbium(III) ions, the terbium(III)-FQs chelates are formed in-situ in an on-capillary derivatization reaction of a microfluidic system. The laser-induced terbium(III)-sensitized luminescence of the chelates is measured at excitation/emission wavelengths of 337/545 nm. The analytes can be separated and quantified within less than 4 min. A solid phase extraction step for analyte preconcentration can be included prior to chelation and microchip capillary electrophoresis. The analytical ranges of the calibration graphs for CIP, ENR and FLU are from 10.6 to 60.0, 10.3 to 51.0, and 11.5 to 58.8 ng mL −1 , respectively, and the detection limits are 3.2, 3.1 and 3.6 ng mL −1 , respectively. The precision was established at two concentration levels of each analyte and revealed relative standard deviations in the range from 3.0 to 10.2 %. The method was applied to the analysis of FQ-spiked water samples. (author)

{alpha}-particle induced reactions on yttrium and terbium

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, S.; Kumar, B.B. [School of Studies in Physics, Vikram University, Ujjain-456010 (India); Rashid, M.H. [Variable Energy Cyclotron Center, 1/AF, Bidhan Nagar, Calcutta (India); Chintalapudi, S.N. [Inter-University Consortium for DAE Facilities, 3/LB, Bidhan Nagar, Calcutta (India)

1997-05-01

The stacked foil activation technique has been employed for the investigation of {alpha}-particle induced reactions on the target elements yttrium and terbium up to 50 MeV. Six excitation functions for the ({alpha},xn) type of reactions were studied using high-resolution HPGe {gamma}-ray spectroscopy. A comparison with Blann{close_quote}s geometric dependent hybrid model has been made using the initial exciton number n{sub 0}=4(4p0h) and n{sub 0}=5(5p0h). A broad general agreement is observed between the experimental results and theoretical predictions with an initial exciton number n{sub 0}=4(4p0h). {copyright} {ital 1997} {ital The American Physical Society}

α-particle induced reactions on yttrium and terbium

International Nuclear Information System (INIS)

Mukherjee, S.; Kumar, B.B.; Rashid, M.H.; Chintalapudi, S.N.

1997-01-01

The stacked foil activation technique has been employed for the investigation of α-particle induced reactions on the target elements yttrium and terbium up to 50 MeV. Six excitation functions for the (α,xn) type of reactions were studied using high-resolution HPGe γ-ray spectroscopy. A comparison with Blann close-quote s geometric dependent hybrid model has been made using the initial exciton number n 0 =4(4p0h) and n 0 =5(5p0h). A broad general agreement is observed between the experimental results and theoretical predictions with an initial exciton number n 0 =4(4p0h). copyright 1997 The American Physical Society

Cerium(terbium, erbium)chloride-choline chloride aqueous systems

International Nuclear Information System (INIS)

Gajfutdinova, R.K.; Zhuravlev, E.F.; Bikbaeva, G.G.; Domrachev, V.N.; Vanskova, G.I.

1985-01-01

To clarify the effect of rare earth nature on mutual solubility of rare earth salts and amines the solubility of solid phases in the systems, consisting of choline chloride, water and cerium, terbium, erbium chlorides, has been studied. It is established, that solubility isotherms of all the systems, testify to the formation of new solid phases of the composition: Ce(Tb, Er)xCl 3 x2C 5 H 14 ONClx3H 2 O. Individuality of new solid phases is proved by DTA method, the composition is confirmed by chemical analysis and data of PMR spectra, for choline chloride and its complexes with rare earth chlorides of the given composition PMR and IR spectra are studied

A thermoluminescence study of Z2-centres in terbium-doped NaCl crystals

International Nuclear Information System (INIS)

Reddy, K.N.; Ahmed, I.M.; Pandaraiah, N.; Rao, U.V.S.; Babu, V.H.

1983-01-01

Thermoluminescence (TL), optical absorption are used to correlate thermal annealing of Z 2 -centres with TL peak occurring around 110 0 C in terbium-doped NaCl crystals. The TL glow peak occurring around 190 0 C is attributed to the thermal annealing of F-centres. The thermal activation parameters are calculated for both Z 2 - and F-centre peaks. (author)

A hydrometallurgical process for the recovery of terbium from fluorescent lamps: Experimental design, optimization of acid leaching process and process analysis.

Science.gov (United States)

Innocenzi, Valentina; Ippolito, Nicolò Maria; De Michelis, Ida; Medici, Franco; Vegliò, Francesco

2016-12-15

Terbium and rare earths recovery from fluorescent powders of exhausted lamps by acid leaching with hydrochloric acid was the objective of this study. In order to investigate the factors affecting leaching a series of experiments was performed in according to a full factorial plan with four variables and two levels (4 2 ). The factors studied were temperature, concentration of acid, pulp density and leaching time. Experimental conditions of terbium dissolution were optimized by statistical analysis. The results showed that temperature and pulp density were significant with a positive and negative effect, respectively. The empirical mathematical model deducted by experimental data demonstrated that terbium content was completely dissolved under the following conditions: 90 °C, 2 M hydrochloric acid and 5% of pulp density; while when the pulp density was 15% an extraction of 83% could be obtained at 90 °C and 5 M hydrochloric acid. Finally a flow sheet for the recovery of rare earth elements was proposed. The process was tested and simulated by commercial software for the chemical processes. The mass balance of the process was calculated: from 1 ton of initial powder it was possible to obtain around 160 kg of a concentrate of rare earths having a purity of 99%. The main rare earths elements in the final product was yttrium oxide (86.43%) following by cerium oxide (4.11%), lanthanum oxide (3.18%), europium oxide (3.08%) and terbium oxide (2.20%). The estimated total recovery of the rare earths elements was around 70% for yttrium and europium and 80% for the other rare earths. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination of trace amounts of rare earth elements in samarium, terbium and disprosium oxides by graphite furnace atomic-absorption spectrometry

International Nuclear Information System (INIS)

Dantas, E.S.K.

1990-01-01

A graphite furnace atomic-absorption spectrometry method for the determination of neodymium, europium, terbium, dysprosium and yttrium at trace level in samarium oxide; of samarium, europium, dysprosium, holmium, erbium and yttrium in terbium oxide and of europium, terbium, holmium, erbium and yttrium in dysprosium oxide was established. The best pyrolysis and atomization temperatures were determined for each lanthanide considered. Calibration curves were obtained for the pure elements, for binary mixtures formed by the matrix and each of the lanthanides studied and, finally, for the complex mixtures constituted by the matrix and all the other lanthanide of the group under scrutiny. This study has been carried out to examine the interference of the presence of one lanthanide on the behaviour of the other, since a lack of linearity on the calibration curves has been observed in some cases. Detection and determination limits have been determined as well. The detection limits encountered were within the range 0.002 to 0.3% for different elements. The precision of the method expressed as the relative standard deviation was calculated for each element present in each of the matrices studied. The conclusion arrived at is that the method can be applied for determining the above mentioned lanthanides present in the matrices studied with purity up to 99.50%. (author)

Synthesis and luminescence properties of europium and terbium complexes with pyridine- or bipyridine-linked oligothiophene ligand

International Nuclear Information System (INIS)

Liu Ping; Huang Mingsheng; Pan Wanzhang; Zhang Yamin; Hu Jianhua; Deng Wenji

2006-01-01

With an aim to develop novel luminescence materials, europium and terbium complexes of 2,5-(2-thiophene)-pyridine (TPY) and 5,5'-bis(5-(2,2'-bithiophene))-2,2'-bipyridine (B2TBPY) were synthesized, and their luminescence properties studied. The complexes exhibit ligand-sensitized emission, which is typical of Eu(III) and Tb(III) ions

Preparation and photoluminescence enhancement in terbium(III ternary complexes with β-diketone and monodentate auxiliary ligands

Directory of Open Access Journals (Sweden)

Devender Singh

2016-12-01

Full Text Available A series of new solid ternary complexes of terbium(III ion based on β-diketone ligand acetylacetone (acac and monodentate auxiliary ligands (aqua/urea/triphenylphosphineoxide/pyridine-N-oxide had been prepared. The structural characterizations of synthesized ternary compounds were studied by means of elemental analysis, infrared (IR, and proton nuclear magnetic resonance (NMR spectral techniques. The optical characteristics were investigated with absorption as well as photoluminescence spectroscopy. Thermal behavior of compounds was examined by TGA/DTA analysis and all metal complexes were found to have good thermal stability. The luminescence decay time of complexes were also calculated by monitoring at emission wavelength corresponding to 5D4 → 7F5 transition. A comparative inspection of the luminescent behavior of prepared ternary compounds was performed in order to determine the function of auxiliary ligands in the enhancement of luminescence intensity produced by central terbium(III ion. The color coordinates values suggested that compounds showed bright green emission in visible region in electromagnetic spectrum. Complexes producing green light could play a significant role in the fabrication of efficient light conversion molecular devices for display purposes and lightning systems.

Autofluorescence-Free Live-Cell Imaging Using Terbium Nanoparticles.

Science.gov (United States)

Cardoso Dos Santos, M; Goetz, J; Bartenlian, H; Wong, K-L; Charbonnière, L J; Hildebrandt, N

2018-04-18

Fluorescent nanoparticles (NPs) have become irreplaceable tools for advanced cellular and subcellular imaging. While very bright NPs require excitation with UV or visible light, which can create strong autofluorescence of biological components, NIR-excitable NPs without autofluorescence issues exhibit much lower brightness. Here, we show the application of a new type of surface-photosensitized terbium NPs (Tb-NPs) for autofluorescence-free intracellular imaging in live HeLa cells. The combination of exceptionally high brightness, high photostability, and long photoluminecence (PL) lifetimes for highly efficient suppression of the short-lived autofluorescence allowed for time-gated PL imaging of intracellular vesicles over 72 h without toxicity and at extremely low Tb-NP concentrations down to 12 pM. Detection of highly resolved long-lifetime (ms) PL decay curves from small (∼10 μm 2 ) areas within single cells within a few seconds emphasized the unprecedented photophysical properties of Tb-NPs for live-cell imaging that extend well beyond currently available nanometric imaging agents.

Investigation of the luminescent properties of terbium-anthranilate complexes and application to the determination of anthranilic acid derivatives in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Arnaud, N.; Georges, J

2003-01-10

The luminescent properties of terbium complexes with furosemide (FR), flufenamic (FF) acid, tolfenamic (TF) acid and mefenamic (MF) acid have been investigated in aqueous solutions. For all four compounds, complexation occurs when the carboxylic acid of the aminobenzoic group is dissociated and is greatly favoured in the presence of trioctylphosphine oxide as co-ligand and Triton X-100 as surfactant. Under optimum conditions, luminescence of the lanthanide ion is efficiently sensitised and the lifetime of the {sup 5}D{sub 4} resonance level of terbium in the complex is ranging between 1 and 1.9 ms, against 0.4 ms for the aqua ion. The sensitivity of the method for the determination of anthranilic acid derivatives is improved by one to two orders of magnitude with respect to that achieved using native fluorescence or terbium-sensitised luminescence in methanol. The limits of detection are 2x10{sup -10}, 5x10{sup -10} and 2x10{sup -9} mol l{sup -1} for flufenamic acid, furosemide and tolfenamic acid, and mefenamic acid, respectively, with within-run RSD values of less than 1%. The method has been applied to the determination of flufenamic acid in spiked calf sera with and without sample pretreatment. Depending on the method and the analyte concentration, the recovery was ranging between 83 and 113% and the lowest concentration attainable in serum samples was close to 1x10{sup -7} mol l{sup -1}.

Resonance energy transfer from quinolinone modified polystyrene-block-poly(styrene-alt-maleic anhydride) copolymer to terbium(III) metal ions

Czech Academy of Sciences Publication Activity Database

Výprachtický, Drahomír; Mikeš, F.; Lokaj, Jan; Pokorná, Veronika; Cimrová, Věra

2015-01-01

Roč. 160, April (2015), s. 27-34 ISSN 0022-2313 R&D Projects: GA ČR GAP106/12/0827; GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : energy transfer * terbium luminescence * quinolinone donor Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.693, year: 2015

Detection of Bacterial Endospores in Soil by Terbium Fluorescence

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Andrea Brandes Ammann

2011-01-01

Full Text Available Spore formation is a survival mechanism of microorganisms when facing unfavorable environmental conditions resulting in “dormant” states. We investigated the occurrence of bacterial endospores in soils from various locations including grasslands (pasture, meadow, allotment gardens, and forests, as well as fluvial sediments. Bacterial spores are characterized by their high content of dipicolinic acid (DPA. In the presence of terbium, DPA forms a complex showing a distinctive photoluminescence spectrum. DPA was released from soil by microwaving or autoclaving. The addition of aluminium chloride reduced signal quenching by interfering compounds such as phosphate. The highest spore content (up to 109 spores per gram of dry soil was found in grassland soils. Spore content is related to soil type, to soil depth, and to soil carbon-to-nitrogen ratio. Our study might provide a basis for the detection of “hot spots” of bacterial spores in soil.

Magnetoresistance in terbium and holmium single crystals

International Nuclear Information System (INIS)

Singh, R.L.; Jericho, M.H.; Geldart, D.J.W.

1976-01-01

The longitudinal magnetoresistance of single crystals of terbium and holmium metals in their low-temperature ferromagnetic phase has been investigated in magnetic fields up to 80 kOe. Typical magnetoresistance isotherms exhibit a minimum which increases in depth and moves to higher fields as the temperature increases. The magnetoresistance around 1 0 K, where inelastic scattering is negligible, has been interpreted as the sum of a negative contribution due to changes in the domain structure and a positive contribution due to normal magnetoresistance. At higher temperatures, a phenomenological approach has been developed to extract the inelastic phonon and spin-wave components from the total measured magnetoresistance. In the temperature range 4--20 0 K (approximately), the phonon resistivity varies as T 3 . 7 for all samples. Approximate upper and lower bounds have been placed on the spin-wave resistivity which is also found to be described by a simple power law in this temperature range. The implications of this result for theoretical treatments of spin-wave resistivity due to s-f exchange interactions are considered. It is concluded that the role played by the magnon energy gap is far less transparent than previously suggested

Compact all-fiber optical Faraday components using 65-wt%-terbium-doped fiber with a record Verdet constant of -32 rad/(Tm).

Science.gov (United States)

Sun, L; Jiang, S; Marciante, J R

2010-06-07

A compact all-fiber Faraday isolator and a Faraday mirror are demonstrated. At the core of each of these components is an all-fiber Faraday rotator made of a 4-cm-long, 65-wt%-terbium-doped silicate fiber. The effective Verdet constant of the terbium-doped fiber is measured to be -32 rad/(Tm), which is 27 x larger than that of silica fiber. This effective Verdet constant is the largest value measured to date in any fiber and is 83% of the Verdet constant of commercially available crystal used in bulk optics-based isolators. Combining the all-fiber Faraday rotator with fiber polarizers results in a fully fusion spliced all-fiber isolator whose isolation is measured to be 19 dB. Combining the all-fiber Faraday rotator with a fiber Bragg grating results in an all-fiber Faraday mirror that rotates the polarization state of the reflected light by 88 +/- 4 degrees .

33 CFR 157.126 - Pumps.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Pumps. 157.126 Section 157.126... Washing (COW) System on Tank Vessels Design, Equipment, and Installation § 157.126 Pumps. (a) Crude oil must be supplied to the COW machines by COW system pumps or cargo pumps. (b) The pumps under paragraph...

Origin of gigantic magnetostriction and crystal field effects in terbium dititanate

International Nuclear Information System (INIS)

Aleksandrov, I.V.; Lidskij, B.V.; Mamsurova, L.G.

1985-01-01

The temperature and magnetic field dependences of the magnetostriction and magnetization and the temperature dependences of the magnetic susceptibility, specific heat and lattice parameter are investigated experimentally in a broad range of temperature and field strength for polycrystalline and single crystal Tb 2 Ti 2 O 7 . A conclusion is drawn regarding the structure of the energy levels of Tb 3+ in Tb 2 Ti 2 O 7 . A qualitative and quantitative explanation of all observed magnetic effects, and in particular of gigantic magnetostriction in Tb 2 Ti 2 O 7 , is presented which is based on the crystal field theory. It is shown that the huge magnitude of the magnetostriction in terbium dititanate is due to the specificity of the energy spectrum of Tb 3+ in Tb 2 Ti 2 O 7

33 CFR 157.155 - COW operations: General.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false COW operations: General. 157.155... Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.155 COW operations: General. (a) The master of a tank vessel having a COW system under § 157.10(e), § 157.10a(a)(2), or 157.10c(b)(2) shall...

Electronic structure of surface-supported bis(phthalocyaninato) terbium(III) single molecular magnets.

Science.gov (United States)

Vitali, Lucia; Fabris, Stefano; Conte, Adriano Mosca; Brink, Susan; Ruben, Mario; Baroni, Stefano; Kern, Klaus

2008-10-01

The electronic structure of isolated bis(phthalocyaninato) terbium(III) molecules, a novel single-molecular-magnet (SMM), supported on the Cu(111) surface has been characterized by density functional theory and scanning tunneling spectroscopy. These studies reveal that the interaction with the metal surface preserves both the molecular structure and the large spin magnetic moment of the metal center. The 4f electron states are not perturbed by the adsorption while a strong molecular/metal interaction can induce the suppression of the minor spin contribution delocalized over the molecular ligands. The calculations show that the inherent spin magnetic moment of the molecule is only weakly affected by the interaction with the surface and suggest that the SMM character might be preserved.

Folate Receptor Targeted Alpha-Therapy Using Terbium-149

CERN Document Server

Müller, Cristina; Haller, Stephanie; Dorrer, Holger; Köster, Ulli; Johnston, Karl; Zhernosekov, Konstantin; Türler, Andreas; Schibli, Roger

2014-01-01

Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range α-particles (Eα = 3.967 MeV) with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09) using folate receptor (FR)-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A) or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq). A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d) compared to untreated controls (A: 21 d). Analysis of blood parameters rev...

40 CFR 157.27 - Unit packaging.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Unit packaging. 157.27 Section 157.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PACKAGING REQUIREMENTS FOR PESTICIDES AND DEVICES Child-Resistant Packaging § 157.27 Unit packaging. Pesticide products...

Crystal structures of two mononuclear complexes of terbium(III nitrate with the tripodal alcohol 1,1,1-tris(hydroxymethylpropane

Directory of Open Access Journals (Sweden)

Thaiane Gregório

2017-02-01

Full Text Available Two new mononuclear cationic complexes in which the TbIII ion is bis-chelated by the tripodal alcohol 1,1,1-tris(hydroxymethylpropane (H3LEt, C6H14O3 were prepared from Tb(NO33·5H2O and had their crystal and molecular structures solved by single-crystal X-ray diffraction analysis after data collection at 100 K. Both products were isolated in reasonable yields from the same reaction mixture by using different crystallization conditions. The higher-symmetry complex dinitratobis[1,1,1-tris(hydroxymethylpropane]terbium(III nitrate dimethoxyethane hemisolvate, [Tb(NO32(H3LEt2]NO3·0.5C4H10O2, 1, in which the lanthanide ion is 10-coordinate and adopts an s-bicapped square-antiprismatic coordination geometry, contains two bidentate nitrate ions bound to the metal atom; another nitrate ion functions as a counter-ion and a half-molecule of dimethoxyethane (completed by a crystallographic twofold rotation axis is also present. In product aquanitratobis[1,1,1-tris(hydroxymethylpropane]terbium(III dinitrate, [Tb(NO3(H3LEt2(H2O](NO32, 2, one bidentate nitrate ion and one water molecule are bound to the nine-coordinate terbium(III centre, while two free nitrate ions contribute to charge balance outside the tricapped trigonal-prismatic coordination polyhedron. No free water molecule was found in either of the crystal structures and, only in the case of 1, dimethoxyethane acts as a crystallizing solvent. In both molecular structures, the two tripodal ligands are bent to one side of the coordination sphere, leaving room for the anionic and water ligands. In complex 2, the methyl group of one of the H3LEt ligands is disordered over two alternative orientations. Strong hydrogen bonds, both intra- and intermolecular, are found in the crystal structures due to the number of different donor and acceptor groups present.

14 CFR 157.7 - FAA determinations.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false FAA determinations. 157.7 Section 157.7... NOTICE OF CONSTRUCTION, ALTERATION, ACTIVATION, AND DEACTIVATION OF AIRPORTS § 157.7 FAA determinations. (a) The FAA will conduct an aeronautical study of an airport proposal and, after consultations with...

33 CFR 157.166 - Hydrocarbon emissions.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Hydrocarbon emissions. 157.166 Section 157.166 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.166 Hydrocarbon emissions. If the...

Hyperfine structure of the odd parity level system in the terbium atom

International Nuclear Information System (INIS)

Stefanska, D; Furmann, B

2017-01-01

Within this work new experimental results concerning the hyperfine structure ( hfs ) in the terbium atom are presented, concerning the odd parity levels system, hitherto only scarcely investigated (apart from the ground term). hfs constants A and B for 113 levels were determined for the first time, and for another 16 levels, which already occurred in our earlier works, supplementary results were obtained; additionally, our earlier results for 93 levels were compiled. The hfs of the odd parity levels was investigated using the method of laser induced fluorescence in a hollow cathode discharge. The hfs of 165 spectral lines, where the levels in question were involved as the upper levels, was recorded. Literature values of hfs constants of the even-parity lower levels (including our own earlier results) greatly facilitated the present data evaluation. (paper)

Terbium fluorescence as a sensitive, inexpensive probe for UV-induced damage in nucleic acids

International Nuclear Information System (INIS)

El-Yazbi, Amira F.; Loppnow, Glen R.

2013-01-01

Graphical abstract: -- Highlights: •Simple, inexpensive, mix-and-read assay for positive detection of DNA damage. •Recognition of undamaged DNA via hybridization to a hairpin probe. •Terbium(III) fluorescence reports the amount of damage by binding to ssDNA. •Tb/hairpin is a highly selective and sensitive fluorescent probe for DNA damage. -- Abstract: Much effort has been focused on developing methods for detecting damaged nucleic acids. However, almost all of the proposed methods consist of multi-step procedures, are limited, require expensive instruments, or suffer from a high level of interferences. In this paper, we present a novel simple, inexpensive, mix-and-read assay that is generally applicable to nucleic acid damage and uses the enhanced luminescence due to energy transfer from nucleic acids to terbium(III) (Tb 3+ ). Single-stranded oligonucleotides greatly enhance the Tb 3+ emission, but duplex DNA does not. With the use of a DNA hairpin probe complementary to the oligonucleotide of interest, the Tb 3+ /hairpin probe is applied to detect ultraviolet (UV)-induced DNA damage. The hairpin probe hybridizes only with the undamaged DNA. However, the damaged DNA remains single-stranded and enhances the intrinsic fluorescence of Tb 3+ , producing a detectable signal directly proportional to the amount of DNA damage. This allows the Tb 3+ /hairpin probe to be used for sensitive quantification of UV-induced DNA damage. The Tb 3+ /hairpin probe showed superior selectivity to DNA damage compared to conventional molecular beacons probes (MBs) and its sensitivity is more than 2.5 times higher than MBs with a limit of detection of 4.36 ± 1.2 nM. In addition, this probe is easier to synthesize and more than eight times cheaper than MBs, which makes its use recommended for high-throughput, quantitative analysis of DNA damage

7 CFR 1900.157-1900.200 - [Reserved

Science.gov (United States)

2010-01-01

... 7 Agriculture 12 2010-01-01 2010-01-01 false [Reserved] 1900.157-1900.200 Section 1900.157-1900... BUSINESS-COOPERATIVE SERVICE, RURAL UTILITIES SERVICE, AND FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE... Assistance to Employees, Relatives, and Associates §§ 1900.157-1900.200 [Reserved] ...

Construction of the energy matrix for complex atoms. Part VIII: Hyperfine structure HPC calculations for terbium atom

Science.gov (United States)

Elantkowska, Magdalena; Ruczkowski, Jarosław; Sikorski, Andrzej; Dembczyński, Jerzy

2017-11-01

A parametric analysis of the hyperfine structure (hfs) for the even parity configurations of atomic terbium (Tb I) is presented in this work. We introduce the complete set of 4fN-core states in our high-performance computing (HPC) calculations. For calculations of the huge hyperfine structure matrix, requiring approximately 5000 hours when run on a single CPU, we propose the methods utilizing a personal computer cluster or, alternatively a cluster of Microsoft Azure virtual machines (VM). These methods give a factor 12 performance boost, enabling the calculations to complete in an acceptable time.

Synthesis and crystal structure of terbium(III) meta-oxoborate Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}); Synthese und Kristallstruktur von Terbium(III)-meta-Oxoborat Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6})

Energy Technology Data Exchange (ETDEWEB)

Nikelski, Tanja; Schleid, Thomas [Institut fuer Anorganische Chemie der Universitaet Stuttgart (Germany)

2003-06-01

The terbium meta-oxoborate Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}) is obtained as single crystals by the reaction of terbium, Tb{sub 4}O{sub 7} and TbCl{sub 3} with an excess of B{sub 2}O{sub 3} in gastight sealed platinum ampoules at 950 C after three weeks. The compound appears to be air- and water-resistant and crystallizes as long, thin, colourless needles which tend to growth-twinning due to their marked fibrous habit. The crystal structure of Tb(BO{sub 2}){sub 3} (orthorhombic, Pnma; a = 1598.97(9), b = 741.39(4), c = 1229.58(7) pm; Z = 16) contains strongly corrugated oxoborate layers {sub {infinity}}{sup 2}{l_brace}(BO{sub 2}){sup -}{r_brace} built of vertex-linked [BO{sub 4}]{sup 5-} tetrahedra (d(B-O) = 143 - 154 pm, and angsph;(O-B-O) = 102-115 ) which spread out parallel (100). The four crystallographically different Tb{sup 3+} cations all exhibit coordination numbers of eight towards the oxygen atoms (d(Tb-O) = 228-287 pm). The corresponding metal cation polyhedra [TbO{sub 8}]{sup 13+} too convene to layers (composition: {sub {infinity}}{sup 2}{l_brace}(Tb{sub 2}O{sub 11}){sup 16-}{r_brace}) which are likewise oriented parallel to the (100) plane. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Das Terbium-meta-Oxoborat Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}) entsteht einkristallin bei der Reaktion von Terbium, Tb{sub 4}O{sub 7} und TbCl{sub 3} mit einem Ueberschuss von B{sub 2}O{sub 3} in gasdicht verschlossenen Platinampullen nach drei Wochen bei 950 C. Die Verbindung ist luft- und wasserstabil und faellt in langen, duennen, farblosen Nadeln an, die aufgrund ihres ausgepraegt faserigen Habitus zur Wachstumsverzwillingung neigen. Die Kristallstruktur von Tb(BO{sub 2}){sub 3} (orthorhombisch, Pnma; a = 1598, 97(9), b = 741, 39(4), c = 1229, 58(7) pm; Z = 16) enthaelt parallel (100) verlaufende, stark gewellte Oxoborat-Schichten {sub {infinity}}{sup 2}{l_brace}(BO{sub 2}){sup -}{r_brace} aus

E.coli O157:H7

Directory of Open Access Journals (Sweden)

Treor Francis Fernandez

2008-06-01

Full Text Available The serious nature of the symptoms of haemorrhagic colitis and HUS and the apparent low infectious dose (<100 cells of E.coli O157:H7 places this food borne pathogen a most serious of known food borne pathogens. Persuasive evidence suggests that healthy cattle are a reservoir of O157 and they can enter the food chain to provide a source of exposure for humans. A possible route of transmission of O157 VTEC may involve infections initially in calves that shed their organism into faecal slurry that may be used on grazing grass. This provides potential for infection of other animals from which the organism may contaminate milk or carcasses at slaughter. Possible sources of VTEC in healthy animals other E.coli O157:H7 than cattle and a wider range of foodstuffs require further investigation. Many features of E.coli O157:H7 strains remain poorly understood. It includes: (i Role of virulent genes in the animal, (ii Mechanism of evolution of the organism, (iii The progress of individual cases of E.coli O157:H7 infection, and (iv The difference in incidence of infection in different geographical areas. [Veterinary World 2008; 1(3.000: 83-87

Sensitive luminescent determination of DNA using the terbium(III)-difloxacin complex

International Nuclear Information System (INIS)

Yegorova, Alla V.; Scripinets, Yulia V.; Duerkop, Axel; Karasyov, Alexander A.; Antonovich, Valery P.; Wolfbeis, Otto S.

2007-01-01

The interaction of the terbium-difloxacin complex (Tb-DFX) with DNA has been examined by using UV-vis absorption and luminescence spectroscopy. The Tb-DFX complex shows an up to 85-fold enhancement of luminescence intensity upon titration with DNA. The long decay times allow additional detection schemes like time-resolved measurements in microplate readers to enhance sensitivity by off-gating short-lived background luminescence. Optimal conditions are found at equimolar concentrations of Tb 3+ and DFX (0.1 or 1 μM) at pH 7.4. Under these conditions, the luminescence intensity is linearly dependent on the concentration of ds-DNAs and ss-DNA between 1-1500 ng mL -1 and 4.5-270 ng mL -1 , respectively. The detection limit is 0.5 ng mL -1 for ds-DNAs and 2 ng mL -1 for ss-DNA. The mechanism for the luminescence enhancement was also studied

Monoxides of small terbium clusters: A density functional theory investigation

Energy Technology Data Exchange (ETDEWEB)

Zhang, G. L.; Yuan, H. K., E-mail: yhk10@swu.edu.cn; Chen, H.; Kuang, A. L.; Li, Y.; Wang, J. Z.; Chen, J. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China)

2014-12-28

To investigate the effect of oxygen atom on the geometrical structures, electronic, and magnetic properties of small terbium clusters, we carried out the first-principles calculations on Tb{sub n}O (n = 1-14) clusters. The capping of an oxygen atom on one trigonal-facet of Tb{sub n} structures is always favored energetically, which can significantly improve the structural stability. The far-infrared vibrational spectroscopies are found to be different from those of corresponding bare clusters, providing a distinct signal to detect the characteristic structures of Tb{sub n}O clusters. The primary effect of oxygen atom on magnetic properties is to change the magnetic orderings among Tb atoms and to reduce small of local magnetic moments of the O-coordinated Tb atoms, both of which serve as the key reasons for the experimental magnetic evolution of an oscillating behavior. These calculations are consistent with, and help to account for, the experimentally observed magnetic properties of monoxide Tb{sub n}O clusters [C. N. Van Dijk et al., J. Appl. Phys. 107, 09B526 (2010)].

Evaluating United States and world consumption of neodymium, dysprosium, terbium, and praseodymium in final products

Science.gov (United States)

Hart, Matthew

This paper develops scenarios of future rare-earth-magnet metal (neodymium, dysprosium, terbium, and praseodymium) consumption in the permanent magnets used in wind turbines and hybrid electric vehicles. The scenarios start with naive base-case scenarios for growth in wind-turbine and hybrid-electric-vehicle sales over the period 2011 to 2020, using historical data for each good. These naive scenarios assume that future growth follows time trends in historical data and does not depend on any exogenous variable. Specifically, growth of each technological market follows historical time trends, and the amount of rare earths used per unit of technology remains fixed. The chosen reference year is 2010. Implied consumptions of the rare earth magnet metals are calculated from these scenarios. Assumptions are made for the material composition of permanent magnets, the market share of permanent-magnet wind turbines and vehicles, and magnet weight per unit of technology. Different scenarios estimate how changes in factors like the material composition of magnets, growth of the economy, and the price of a substitute could affect future consumption. Each scenario presents a different method for reducing rare earth consumption and could be interpreted as potential policy choices. In 2010, the consumption (metric tons, rare-earth-oxide equivalent) of each rare-earth-magnet metal was as follows. Total neodymium consumption in the world for both technologies was 995 tons; dysprosium consumption was 133 tons; terbium consumption was 50 tons; praseodymium consumption was zero tons. The base scenario for wind turbines shows there could be strong, exponential growth in the global wind turbine market. New U.S. sales of hybrid vehicles would decline (in line with the current economic recession) while non-U.S. sales increase through 2020. There would be an overall increase in the total amount of magnetic rare earths consumed in the world. Total consumption of each rare earth in the short

Determination of sertraline in pharmaceutical and biological samples using 1, 10-phenanthroline-terbium probe and silver nanoparticles enhanced fluorescence

Energy Technology Data Exchange (ETDEWEB)

Lotfi, Ali, E-mail: alilotfi67@gmail.com [Young Researchers and Elite Club, Tabriz Branch, Islamic Azad University, Tabriz (Iran, Islamic Republic of); Manzoori, Jamshid L. [Department of Chemistry, Tabriz Branch, Islamic Azad University, Tabriz (Iran, Islamic Republic of); Mohagheghi, Arash [Clinical Psychiatry Research Center, Tabriz University of Medical Sciences, Tabriz (Iran, Islamic Republic of)

2017-05-15

Sertraline is an antidepressant widely prescribed for major depressive disorders. In this contribution we report a novel, rapid and sensitive spectrofluorimetric technique, developed and validated for the determination of sertraline in pharmaceutical, human urine and human plasma samples, based on the fluorescence enhancement of the sertraline by 1, 10-phenanthroline-terbium probe with Ag nanoparticles (AgNPs). The effect of pH, buffer concentration, the order of addition of reagents, terbium and 1, 10-phenanthroline concentrations, and concentration of Ag nanoparticles (AgNPs) as well as reaction time on the fluorescence intensity were investigated and the optimum conditions were determined. The linear range for determination of sertraline was obtained as 0.001–3 mg L{sup −1}. The limit of detection (b+3s) and the limit of quantification was calculated as 2.9×10{sup −4} mg L{sup −1} and 9.8×10{sup −4} mg L{sup −1}, respectively. The interference effects of common excipients found in pharmaceutical preparations were studied. The presented technique was used to determine the sertraline in pharmaceutical samples, human urine and plasma as real samples. The presented method was indicated a comparable results with the standard analytical techniques for sertraline. Good linearity, reproducibility, recovery and limit of detection have made this method suitable for determination of sertraline in various types of samples.

Determination of sertraline in pharmaceutical and biological samples using 1, 10-phenanthroline-terbium probe and silver nanoparticles enhanced fluorescence

International Nuclear Information System (INIS)

Lotfi, Ali; Manzoori, Jamshid L.; Mohagheghi, Arash

2017-01-01

Sertraline is an antidepressant widely prescribed for major depressive disorders. In this contribution we report a novel, rapid and sensitive spectrofluorimetric technique, developed and validated for the determination of sertraline in pharmaceutical, human urine and human plasma samples, based on the fluorescence enhancement of the sertraline by 1, 10-phenanthroline-terbium probe with Ag nanoparticles (AgNPs). The effect of pH, buffer concentration, the order of addition of reagents, terbium and 1, 10-phenanthroline concentrations, and concentration of Ag nanoparticles (AgNPs) as well as reaction time on the fluorescence intensity were investigated and the optimum conditions were determined. The linear range for determination of sertraline was obtained as 0.001–3 mg L −1 . The limit of detection (b+3s) and the limit of quantification was calculated as 2.9×10 −4 mg L −1 and 9.8×10 −4 mg L −1 , respectively. The interference effects of common excipients found in pharmaceutical preparations were studied. The presented technique was used to determine the sertraline in pharmaceutical samples, human urine and plasma as real samples. The presented method was indicated a comparable results with the standard analytical techniques for sertraline. Good linearity, reproducibility, recovery and limit of detection have made this method suitable for determination of sertraline in various types of samples.

Self-assembly of Terbium(III)-based metal-organic complexes with two-photon absorbing active

Science.gov (United States)

Li, Dandan; Shao, Nanqi; Sun, Xianshun; Zhang, Guocui; Li, Shengli; Zhou, Hongping; Wu, Jieying; Tian, Yupeng

2014-12-01

Hybrid complexes based on D-π-A type dyes p-aminostyryl-pyridinum and Terbium(III) complex anion (1, 2) have been synthesized by ionic exchange reaction. Meanwhile two different alkyl-substituted amino groups were used as electron donors in organic dyes cations. The synthesized complexes were characterized by element analysis. In addition, the structural features of them were systematic studied by single crystal X-ray diffraction analysis. Their linear properties have been systematically investigated by absorption spectra and fluorescence, the results show that the energy transfer takes place from the trans-4-[4‧-(N,N-diethylamino)styryl]-N-methyl pyridinium (2‧) cation to Tb(III). In addition, complex 2 exhibit a large two-photon absorption coefficient β: 0.044 cm/GW at 710 nm.

Solid-phase synthesis of compounds of europium and terbium with nitrogen-containing heterocyclic compounds under mechanical activation

International Nuclear Information System (INIS)

Kalinovskaya, I.V.; Karasev, V.E.

2000-01-01

Effect of solvents and parameters of mechanical treatment on basic regularities of synthesis of rare earth compounds with nitrogen-containing heterocyclic compounds is studied. It is shown that interaction on europium (3) and terbium (3) nitrates with nitrogen-containing heterocyclic compounds leads to formation of compounds of Ln(NO 3 )·2D composition, where Ln=Eu, Tb; D=2,2-dipyridyl, 1,10-phenanthroline, diphenylguanidine. Effect of conditions of mechanical treatment and different additions on process and yield of products is studied. Compounds prepared are characterized by the methods of chemical element analysis, IR spectroscopy and luminescent spectroscopy [ru

Luminescent hybrid films obtained by covalent grafting of terbium complex to silica network

International Nuclear Information System (INIS)

Liu Fengyi; Fu Lianshe; Wang Jun; Liu Ze; Li Huanrong; Zhang Hongjie

2002-01-01

Luminescent hybrid thin films consisting of terbium complex covalently bonded to a silica-based network have been obtained in situ via a sol-gel approach. A new monomer, N-(4-benzoic acid-yl), N'-(propyltriethoxysilyl)urea (PABI), has been synthesized by grafting isocyanatopropyltriethoxysilane (ICPTES) to p-aminobenzoic acid and characterized by 1 H NMR, IR and MS. The monomer acts as a ligand for Tb 3+ ion and as a sol-gel precursor. Band emission from Tb 3+ ion due to an efficient ligand-to-metal energy transfer was observed by UV excitation. The decay curves of Tb 3+ in the hybrid films were measured. The energy difference between the triplet state energy of PABI and the 5 D 4 level of Tb 3+ ion falls in the exciting range to sensitize Tb 3+ ion fluorescence

Stable gastric pentadecapeptide BPC 157 and bupivacaine.

Science.gov (United States)

Zivanovic-Posilovic, Gordana; Balenovic, Diana; Barisic, Ivan; Strinic, Dean; Stambolija, Vasilije; Udovicic, Mario; Uzun, Sandra; Drmic, Domagoj; Vlainic, Josipa; Bencic, Martina Lovric; Sindic, Aleksandra; Seiwerth, Sven; Sikiric, Predrag

2016-12-15

Bupivacaine toxicity following accidental overdose still lacks therapeutic solution. However, there are major arguments for testing BPC 157 against bupivacaine toxicity in vivo in rats, in particular, and then finally, in vitro. These are: the lack of any known BPC 157 toxicity, a lifesaving effect via the mitigation of arrhythmias in rats underwent hyperkalemia or digitalis toxicity, the elimination of hyperkalemia and arrhythmias in rats underwent succinylcholine toxicity and finally, the reduction of potassium-induced depolarization in vitro (in HEK293 cells) in severe hyperkalemia. Most importantly, BPC 157 successfully prevents and counteracts bupivacaine cardiotoxicity; BPC 157 is effective even against the worst outcomes such as a severely prolonged QRS complex. Here, rats injected with bupivacaine (100mg/kg IP) exhibited bradycardia, AV-block, ventricular ectopies, ventricular tachycardia, T-wave elevation and asystole. All of the fatalities had developed T-wave elevation, high-degree AV-block, respiratory arrest and asystole. These were largely counteracted by BPC 157 administration (50µg/kg, 10µg/kg, 10ng/kg, or 10pg/kg IP) given 30min before or 1min after the bupivacaine injection. When BPC 157 was given 6min after bupivacaine administration, and after the development of prolonged QRS intervals (20ms), the fatal outcome was markedly postponed. Additionally, the effect of bupivacaine on cell membrane depolarization was explored by measuring membrane voltages (Vm) in HEK293 cells. Bupivacaine (1mM) alone caused depolarization of the cells, while in combination with BPC 157 (1µm), the bupivacaine-induced depolarization was inhibited. Together, these findings suggest that the stable gastric pentadecapeptide BPC 157 should be a potential antidote for bupivacaine cardiotoxicity. Copyright © 2016 Elsevier B.V. All rights reserved.

15 CFR 930.157 - Mediation and informal negotiations.

Science.gov (United States)

2010-01-01

... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Mediation and informal negotiations. 930.157 Section 930.157 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... Activities Having Interstate Coastal Effects § 930.157 Mediation and informal negotiations. The relevant...

Nanostructured Layered Terbium Hydroxide Containing NASIDs: In Vitro Physicochemical and Biological Evaluations.

Science.gov (United States)

Gu, Qing-Yang; Qiu, Xiao; Liu, Jing-Jing; Fu, Min; Chao, Jian-Ping; Ju, Rui-Jun; Li, Xue-Tao

2018-08-01

Diclofenac sodium (abrr. DS) and indomethacin (abrr. IMC) have been intercalated into the layered terbium hydroxide (LTbH) by anion exchange method. Chemical compositions, thermostability, morphology, luminescence property, release behaviors and cytotoxic effects have been investigated. The DS molecules may embed between layers with a bilayered arrangement and the IMC may correspond to a monolayered arrangement. The Tb3+ luminescence in DS-LTbH and IMC-LTbH composites were enhanced compared with LTbH precusor and the luminescence intensity increases with the deprotonation degree. Drug release was measured with HPLC, and LTbH showed sustained release behavior on both drugs. Further In Vitro evaluation were carried out on cancer cells. Cytotoxic effect of LTbH was observed with a sulforhodamine B colorimetric assay on a variety of cancer cell lines, which revealed that the LTbH showed little cytotoxic effect. Results indicate LTbH may offer a potential vehicle as an effective drug delivery system along with diagnostic integration.

Raman spectra of terbium trichloride, phosphorus pentachloride and their molten mixtures; Spektry kombinatsionnogo rasseyaniya sveta trikhlorida terbiya, pentakhlorida fosfora i ikh rasplavlennykh smesej

Energy Technology Data Exchange (ETDEWEB)

Salyulev, A B; Zakir' yanova, I D [UrO RAN, Inst. Vysokotemperaturnoj Ehlektrokhimii, Ekaterinburg (Russian Federation)

2008-03-15

Raman spectroscopy was used to study in situ the behavior of individual terbium trichloride and phosphorus pentachloride in different aggregative states as a function of temperature, and of solutions of PCl{sub 5} vapors in molten TbCl{sub 3}. A conclusion is drawn about their structure and the nature of phase transformations and chemical reactions in wide ranges of temperature and saturated vapor pressures.

18 CFR 157.211 - Delivery points.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Delivery points. 157... for Certain Transactions and Abandonment § 157.211 Delivery points. (a) Construction and operation—(1... delivery point, excluding the construction of certain delivery points subject to the prior notice...

46 CFR 45.157 - Scuppers and gravity drains.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Scuppers and gravity drains. 45.157 Section 45.157 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Conditions of Assignment § 45.157 Scuppers and gravity drains. Scuppers and gravity deck drains from spaces...

33 CFR 157.156 - COW operations: Meeting manual requirements.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false COW operations: Meeting manual... CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.156 COW operations... COW system under §§ 157.10(e), 157.10a(a)(2), or 157.10c(b)(2) that has the Crude Oil Washing...

Thermoluminescence of cerium and terbium -doped calcium pyrophosphate

Energy Technology Data Exchange (ETDEWEB)

Roman L, J.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Lozano R, I. B.; Diaz G, J. A. I., E-mail: jesus.roman@nucleares.unam.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)

2015-10-15

The aim of this work is to report the thermoluminescence (Tl) response of Calcium Pyrophosphate phosphor doped with Cerium and Terbium impurities (Ca{sub 2}P{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+}). The phosphors were synthesized using the co-precipitation method and annealed at 900 degrees C by two hours for obtain the β phase. The intentional doping with Ce and Tb ions was 1 at.% and 0.1 at.%, whereas in the EDS results the concentration of impurities was 0.39 at.% and 0.05 at.%, respectively. The superficial morphology of phosphor is mainly composed by thin wafers of different size. All samples were exposed to gamma rays from {sup 60}Co in the Gammacell-200 irradiator. The Tl response of the phosphor was measured from Rt up to 350 degrees C and under nitrogen atmosphere in a Harshaw TLD 3500 reader. The glow curves of the Ca{sub 2}P{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} powders showed a broad intense Tl peak centered at 165 degrees C and a shoulder at approximate 260 degrees C was observed. A linear Tl response in the range of absorbed dose of 0.2 to 10 Gy was obtained. Tl glow curves were analyzed using the initial rise (IR)and computerized glow curve deconvolution methods to evaluate the kinetics parameters such as activation energy (E), frequency factor (s) and kinetic order (b). (Author)

18 CFR 157.37 - Project design.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Project design. 157.37... Seasons for Alaska Natural Gas Transportation Projects § 157.37 Project design. In reviewing any... proposed project has been designed to accommodate the needs of shippers who have made conforming bids...

Topological data analysis of Escherichia coli O157:H7 and non-O157 survival in soils

Science.gov (United States)

Shiga toxin-producing E. coli O157:H7 and non-O157 have been implicated in many foodborne illnesses caused by the consumption of contaminated fresh produce. However, data on their persistence in major fresh produce-growing soils are limited due to the complexity in datasets generated from different ...

Effects of time on the magnetic properties of terbium-doped LaMnO3

International Nuclear Information System (INIS)

Liu Weibin; Zhang Yingtang; Guan Wen; Kinsman, William; Yuan Xinqiang; Chen Ziyu

2012-01-01

The magnetic properties of the perovskite form of LaMnO 3 have been shown strong interest in recent years due to its high potential for use in magnetic devices. In this paper, the magnetic properties of a 30% terbium-doped LaMnO 3 (LMTO) perovskite manganite synthesized by a conventional solid-state reaction were investigated. Data on these properties was recorded periodically via SQUID and VSM to reveal it to be best described magnetically as a spin glass system. Thus, the time effect must be taken into consideration in instantaneously determining this material’s spin glass state as well as the overall magnetic properties in the absence of a magnetic field. The results of this paper point to a more in-depth understanding of the change in magnetic properties associated with doped LaMnO 3 .

Escherichia coli O157:H7 and rectoanal junction cell interactome

Science.gov (United States)

Introduction. Cattle are the primary E. coli O157 (O157) reservoir and principal source of human infection. The anatomical site of O157 persistence is the bovine recto-anal (RAJ) junction; hence, an in-depth understanding of O157-RAJ interactions will help develop novel modalities to limit O157 in c...

Influence of crystallite size and temperature on the antiferromagnetic helices of terbium and holmium metal

Energy Technology Data Exchange (ETDEWEB)

Bick, Jens-Peter; Michels, Andreas [Universitaet des Saarlandes, D-66041 Saarbruecken (Germany); University of Luxembourg, L-1511 Luxembourg (Luxembourg); Ferdinand, Adrian; Birringer, Rainer [Universitaet des Saarlandes, D-66041 Saarbruecken (Germany); Baller, Joerg; Sanctuary, Roland [University of Luxembourg, L-1511 Luxembourg (Luxembourg); Philippi, Stefan [Leibniz Institute for Solid State and Materials Research, D-01069 Dresden (Germany); Lott, Dieter [GKSS Research Center, D-21502 Geesthacht (Germany); Balog, Sandor [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Rotenberg, Eli [Lawrence Berkeley National Laboratory, California 94720 (United States); Kaindl, Guenter [Freie Universitaet Berlin, D-14195 Berlin-Dahlem (Germany); Doebrich, Kristian M. [Freie Universitaet Berlin, D-14195 Berlin-Dahlem (Germany); Max-Born-Institut, D-12489 Berlin (Germany)

2011-07-01

We report on the results of grain-size and temperature-dependent magnetization, specific-heat, neutron-scattering, and angle-resolved photoelectron spectroscopy (ARPES) experiments on the heavy rare-earth metals terbium and holmium, with particular emphasis on the temperature regions where the helical antiferromagnetic phases exist. In contrast to Ho, we find that the helical structure in Tb is relative strongly affected by microstructural disorder, specifically, it can no longer be detected for the smallest studied grain size of D=18 nm. Moreover, in coarse-grained Tb a helical structure persists even in the ferromagnetic regime, down to about T=215 K, in agreement with the ARPES data, which reveal a nesting feature of the Fermi surface at the L point of the Brillouin zone at T=210 K.

Isolation and genomic characterization of Escherichia coli O157:NM ...

African Journals Online (AJOL)

Human diseases caused by Escherichia coli O157:NM and E. coli O157:H7 strains have been reported throughout the world. In developed countries, serotype O157:H7 represents the major cause of human diseases; however, there have been increasing reports of non-O157 Shiga toxin (Stx)-producing E. coli strains ...

40 CFR 205.157-3 - Configuration identification.

Science.gov (United States)

2010-07-01

...-3 Section 205.157-3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.157-3 Configuration...) intake ducting; and (iii) air cleaner element. (3) Vehicle drive train: (i) Chain; and (ii) shaft. (4...

33 CFR 157.12f - Workshop functional test requirements.

Science.gov (United States)

2010-07-01

... CARRYING OIL IN BULK Design, Equipment, and Installation § 157.12f Workshop functional test requirements... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Workshop functional test requirements. 157.12f Section 157.12f Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND...

Functional role and prognostic significance of CD157 in ovarian carcinoma.

Science.gov (United States)

Ortolan, Erika; Arisio, Riccardo; Morone, Simona; Bovino, Paola; Lo-Buono, Nicola; Nacci, Giulia; Parrotta, Rossella; Katsaros, Dionyssios; Rapa, Ida; Migliaretti, Giuseppe; Ferrero, Enza; Volante, Marco; Funaro, Ada

2010-08-04

CD157, an ADP-ribosyl cyclase-related cell surface molecule, regulates leukocyte diapedesis during inflammation. Because CD157 is expressed in mesothelial cells and diapedesis resembles tumor cell migration, we investigated the role of CD157 in ovarian carcinoma. We assayed surgically obtained ovarian cancer and mesothelial cells and both native and engineered ovarian cancer cell lines for CD157 expression using flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR), and for adhesion to extracellular matrices, migration, and invasion using cell-based assays. We investigated invasion of human peritoneal mesothelial cells by serous ovarian cancer cells with a three-dimensional coculture model. Experiments were performed with or without CD157-blocking antibodies. CD157 expression in tissue sections from ovarian cancer patients (n = 88) was examined by immunohistochemistry, quantified by histological score (H score), and categorized as at or above or below the median value of 60, and compared with clinical parameters. Statistical tests were two-sided. CD157 was expressed by ovarian cancer cells and mesothelium, and it potentiated the adhesion, migration, and invasion of serous ovarian cancer cells through different extracellular matrices. CD157-transfected ovarian cancer cells migrated twice as much as CD157-negative control cells (P = .001). Blockage of CD157 inhibited mesothelial invasion by serous ovarian cancer cells in a three-dimensional model. CD157 was expressed in 82 (93%) of the 88 epithelial ovarian cancer tissue specimens. In serous ovarian cancer, patients with CD157 H scores of 60 or greater had statistically significantly shorter disease-free survival and overall survival than patients with lower CD157 H scores (CD157 H score > or =60 vs or =60 vs <60: median overall survival = 45 months, 95% CI = 21.21 to 68.79 vs unreached, P = .024). Multivariable Cox regression showed that CD157 is an independent prognostic factor for recurrence

Effects of time on the magnetic properties of terbium-doped LaMnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Liu Weibin [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Zhang Yingtang, E-mail: zhangyingtang76@mail.xjtu.edu.cn [School of Material Science and Engineering, Institute of Functional Material, Shaanxi University of Technology, Hanzhong 723003 (China); State Key Laboratory of Electrical Insulation and Power Equipment and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Guan Wen [State Key Laboratory of Electrical Insulation and Power Equipment and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Kinsman, William [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Yuan Xinqiang [School of Material Science and Engineering, Institute of Functional Material, Shaanxi University of Technology, Hanzhong 723003 (China); Chen Ziyu [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

2012-09-01

The magnetic properties of the perovskite form of LaMnO{sub 3} have been shown strong interest in recent years due to its high potential for use in magnetic devices. In this paper, the magnetic properties of a 30% terbium-doped LaMnO{sub 3} (LMTO) perovskite manganite synthesized by a conventional solid-state reaction were investigated. Data on these properties was recorded periodically via SQUID and VSM to reveal it to be best described magnetically as a spin glass system. Thus, the time effect must be taken into consideration in instantaneously determining this material's spin glass state as well as the overall magnetic properties in the absence of a magnetic field. The results of this paper point to a more in-depth understanding of the change in magnetic properties associated with doped LaMnO{sub 3}.

33 CFR 157.600 - Purpose and applicability.

Science.gov (United States)

2010-07-01

... (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING...-Petroleum Oil § 157.600 Purpose and applicability. (a) The purpose of this subpart is to establish mandatory... non-petroleum oil. (b) This subpart applies to each tank vessel specified in § 157.01 of this part...

33 CFR 157.170 - COW equipment: Removal.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false COW equipment: Removal. 157.170... Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.170 COW equipment: Removal. (a) Whenever a deck mounted COW machine is removed from the tank, the master shall ensure that: (1) The supply...

24 CFR 982.157 - Budget and expenditure.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Budget and expenditure. 982.157... and PHA Administration of Program § 982.157 Budget and expenditure. (a) Budget submission. Each PHA fiscal year, the PHA must submit its proposed budget for the program to HUD for approval at such time and...

40 CFR 157.30 - Voluntary use of child-resistant packaging.

Science.gov (United States)

2010-07-01

... packaging. 157.30 Section 157.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PACKAGING REQUIREMENTS FOR PESTICIDES AND DEVICES Child-Resistant Packaging § 157.30 Voluntary use of child-resistant packaging. A registrant whose product is not required to be in child...

Sensitivity improvement of Cerenkov luminescence endoscope with terbium doped Gd{sub 2}O{sub 2}S nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Cao, Xin; Chen, Xueli, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn; Cao, Xu; Zhan, Yonghua; Liang, Jimin, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn [Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education and School of Life Science and Technology, Xidian University, Xi' an, Shaanxi 710071 (China); Kang, Fei; Wang, Jing [Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China); Wu, Kaichun [Department of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China)

2015-05-25

Our previous study showed a great attenuation for the Cerenkov luminescence endoscope (CLE), resulting in relatively low detection sensitivity of radiotracers. Here, a kind of radioluminescence nanoparticles (RLNPs), terbium doped Gd{sub 2}O{sub 2}S was mixed with the radionuclide {sup 68}Ga to enhance the intensity of emitted luminescence, which finally improved the detection sensitivity of the CLE by using the radioluminescence imaging technique. With the in vitro and in vivo pseudotumor experiments, we showed that the use of RLNPs mixed with the radionuclide {sup 68}Ga enabled superior sensitivity compared with the radionuclide {sup 68}Ga only, with 50-fold improvement on detection sensitivity, which guaranteed meeting the demands of the clinical diagnosis of gastrointestinal tract tumors.

Sonochemical synthesis of terbium tungstate for developing high power supercapacitors with enhanced energy densities.

Science.gov (United States)

Sobhani-Nasab, Ali; Rahimi-Nasrabadi, Mehdi; Naderi, Hamid Reza; Pourmohamadian, Vafa; Ahmadi, Farhad; Ganjali, Mohammad Reza; Ehrlich, Hermann

2018-07-01

Sonochemically prepared nanoparticles of terbium tungstate (TWNPs) were evaluated through scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, and the optimal products were further characterized in terms of their electrochemical properties using conventional and continuous cyclic voltammetry (CV, and CCV), galvanostatic charge/discharge technique, and electrochemical impedance spectroscopy (EIS). The CV studies indicated the TWNPs to have specific capacitance (SC) values of 336 and 205 F g -1 at 1 and 200 mV s -1 , and galvanostatic charge-discharge tests revealed the SC of the TWNP-based electrodes to be 300 F g -1 at 1 Ag -1 . Also continuous cyclic voltammetry evaluations proved the sample as having a capacitance retention value of 95.3% after applying 4000 potential cycles. In the light of the results TWNPs were concluded as favorable electrode materials for use in hybrid vehicle systems. Copyright © 2018 Elsevier B.V. All rights reserved.

27 CFR 25.157 - Determination of tax on bottled beer.

Science.gov (United States)

2010-04-01

... bottled beer. 25.157 Section 25.157 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS BEER Tax on Beer Determination of Tax § 25.157 Determination of tax on bottled beer. The quantities of bottled beer removed subject to tax shall be computed to...

Incidence of Escherichia coli O157:H7 in Thailand

International Nuclear Information System (INIS)

Sukhumungoon, P.

2015-01-01

Entero hemorrhagic Escherichia coli (EHEC) especially serotype O157:H7 is one of the important food-borne pathogens because it is able to produce crucial toxins Shiga. However, the outbreak of this organism in Thailand has not been reported. Antibody to O157 antigen was detected in some Thai populations and Shiga toxin-producing E. coli were detected in low numbers of clinical specimens. Interestingly, some E. coli that showed positive to O157 fimbriae probe and lack of virulence gene were isolated from certain patients and one isolate of E. coli O157:H7 which possessed stx1, stx2v was detected in a normal child. In addition, the incidence of E. coli O157:H7 strains were monitored by the samples from cattle and retail beef in Thailand although their inability to produce toxins or produce in a low concentration was demonstrated. This review discusses the incidences of E. coli O157 in clinical and environmental samples of Thailand including the transmission possibility of this bacterium across the Thai border through food trade. (author)

Study of the nucleotide binding site of the yeast Schizosaccharomyces pombe plasma membrane H+-ATPase using formycin triphosphate-terbium complex

International Nuclear Information System (INIS)

Ronjat, M.; Lacapere, J.J.; Dufour, J.P.; Dupont, Y.

1987-01-01

The plasma membrane of yeasts contains an H+-ATPase similar to the other cation transport ATPases of eukaryotic organisms. This enzyme has been purified and shows H+ transport in reconstituted vesicles. In the presence of Mg2+, formycin triphosphate (FTP) is hydrolyzed by the H+-ATPase and supports H+ transport. When combined with terbium ion, FTP (Tb-FTP) and ATP (Tb-ATP) are no longer hydrolyzed. Competition between Mg-ATP and Tb-FTP for ATP hydrolysis indicates that terbium-associated nucleotides bind to the catalytic site of the H+-ATPase. The fluorescent properties of the Tb-FTP complex were used to study the active site of the H+-ATPase. Fluorescence of Tb-FTP is greatly enhanced upon binding into the nucleotide site of H+-ATPase with a dissociation constant of 1 microM. Tb-ATP, Tb-ADP, and Tb-ITP are competitive inhibitors of Tb-FTP binding with Ki = 4.5, 5.0, and 6.0 microM, respectively. Binding of Tb-FTP is observed only in the presence of an excess of Tb3+ with an activation constant Ka = 25 microM for Tb3+. Analysis of the data reveals that the sites for Tb-FTP and Tb3+ binding are independent entities. In standard conditions these sites would be occupied by Mg-ATP and Mg2+, respectively. These findings suggest an important regulatory role of divalent cations on the activity of H+-ATPase. Replacement of H 2 O by D 2 O in the medium suggests the existence of two types of nucleotide binding sites differing by the hydration state of the Tb3+ ion in the bound Tb-FTP complex

Protection against an infectious disease by enterohaemorrhagic E. coli 0-157.

Science.gov (United States)

Ota, A

1999-07-01

Preventive measures against infection by enterohaemorrhagic E. coli 0-157 are described. Eating yoghurt and Kefir supposedly induces more bifid bacteria and lactic acid bacteria to colonize in the intestines, thereby protecting humans from infection by E. coli 0-157. Some foods, such as plum extract, act as a mild antibiotic and produce an acidic environment within the intestine, thus interfering with growth of the E. coli 0-157. The natural colonization of harmless E. coli or other bacteria that are more powerful than E. coli 0-157 can possibly protect against infection. A vaccination against E. coli 0-157 H7 may also be effective. In addition, it has been suggested that the correct levels of nitric oxide and calcium in the blood may activate immunity and protect against infection by E. coli 0-157.

Complete Stokes polarimetry of magneto-optical Faraday effect in a terbium gallium garnet crystal at cryogenic temperatures.

Science.gov (United States)

Majeed, Hassaan; Shaheen, Amrozia; Anwar, Muhammad Sabieh

2013-10-21

We report the complete determination of the polarization changes caused in linearly polarized incident light due to propagation in a magneto-optically active terbium gallium garnet (TGG) single crystal, at temperatures ranging from 6.3 to 300 K. A 28-fold increase in the Verdet constant of the TGG crystal is seen as its temperature decreases to 6.3 K. In contrast with polarimetry of light emerging from a Faraday material at room temperature, polarimetry at cryogenic temperatures cannot be carried out using the conventional fixed polarizer-analyzer technique because the assumption that ellipticity is negligible becomes increasingly invalid as temperature is lowered. It is shown that complete determination of light polarization in such a case requires the determination of its Stokes parameters, otherwise inaccurate measurements will result with negative implications for practical devices.

TRUPACT-II 157 Examination Report

International Nuclear Information System (INIS)

Barry H. O'Brien; Jeffrey M. Lacy; Kip E. Archibald

2003-01-01

This report presents the results of examination and recovery activities performed on the TRUPACT-II 157 shipping container. The container was part of a contact-handled transuranic waste shipment being transported on a truck to the Waste Isolation Pilot Plant in New Mexico when an accident occurred. Although the transport vehicle sustained only minor damage, airborne transuranic contamination was detected in air samples extracted from inside TRUPACT-II 157 at the Waste Isolation Pilot Plant. Consequently, the shipping container was rejected, resealed, and returned to the Idaho National Engineering and Environmental Laboratory where the payload was disassembled, examined, and recovered for subsequent reshipment to the Waste Isolation Pilot Plant. This report documents the results of those activities

TRUPACT-II 157 Examination Report

Energy Technology Data Exchange (ETDEWEB)

Barry H. O& #39; Brien; Jeffrey M. Lacy; Kip E. Archibald

2003-12-01

This report presents the results of examination and recovery activities performed on the TRUPACT-II 157 shipping container. The container was part of a contact-handled transuranic waste shipment being transported on a truck to the Waste Isolation Pilot Plant in New Mexico when an accident occurred. Although the transport vehicle sustained only minor damage, airborne transuranic contamination was detected in air samples extracted from inside TRUPACT-II 157 at the Waste Isolation Pilot Plant. Consequently, the shipping container was rejected, resealed, and returned to the Idaho National Engineering and Environmental Laboratory where the payload was disassembled, examined, and recovered for subsequent reshipment to the Waste Isolation Pilot Plant. This report documents the results of those activities.

33 CFR 157.124 - COW tank washing machines.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false COW tank washing machines. 157... OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Design, Equipment, and Installation § 157.124 COW tank washing machines. (a) COW machines must be permanently mounted in each cargo tank. (b...

Effect of carvacrol on O157 and non-O157 Shiga toxin producing Escherichia coli

Directory of Open Access Journals (Sweden)

Alexandros Stratakos

2017-06-01

Full Text Available Shiga toxin Escherichia coli (STEC strains are important foodborne bacteria linked to diarrhea, enteritis, hemolytic-uremic syndrome and in some cases death. E. coli O157:H7 is the most common strain amongst STECs however non-O157 STECs have been connected with several outbreaks on an international level.  The use of natural plant extracts to reduce the risk from foodborne pathogens is gaining increasing importance. Therefore in this study, we tested the antibacterial effect of carvacrol, a major component of oregano essential oil, on E. coli serogroups O157, O26, O45, O103, O111, O121, O145 as well as serogroup O104 responsible for the massive outbreak in Germany in 2011. Carvacrol showed antibacterial effect on all strains tested. The relative electric conductivity was assessed in order to investigate the changes in membrane permeability and thus to investigate the antimicrobial mechanism of carvacrol. Results showed that the relative conductivity increased with increasing concentrations of carvacrol which showed that there was an increasing leakage of electrolytes due to disruption of the cell membrane. The data presented here revealed that carvacrol has the potential to be used as a natural antimicrobial against STECs.

[Survival of VTEC O157 and non-O157 in water troughs and bovine feces].

Science.gov (United States)

Polifroni, Rosana; Etcheverría, Analía I; Arroyo, Guillermo H; Padola, Nora L

2014-01-01

Verotoxin-producing Escherichia coli (VTEC) is the etiologic agent of hemolytic-uremic syndrome (HUS), which typically affects children ranging in age from six months to five years old. Transmission is produced by consumption of contaminated food, by direct contact with animals or the environment and from person to person. In previous studies we determined that the environment of a dairy farm is a non-animal reservoir; thus, we proposed to study the survival of 4 VTEC isolates (O20:H19; O91:H21; O157:H7 and O178:H19) in sterile water troughs and bovine feces by viable bacteria count and detection of virulence genes by PCR. It was demonstrated that the survival of different VTEC isolates (O157 and non-O157) varied in terms of their own characteristics as well as of the environmental conditions where they were found. The main differences between isolates were their survival time and the maximal counts reached. The competitive and adaptive characteristics of some isolates increase the infection risk for people that are visiting or working on a farm, as well as the risk for reinfection of the animals and food contamination. Copyright © 2014 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Picomolar traces of americium(III) introduce drastic changes in the structural chemistry of terbium(III). A break in the ''gadolinium break''

Energy Technology Data Exchange (ETDEWEB)

Welch, Jan M. [TU Wien, Atominstitut, Vienna (Austria); Mueller, Danny; Knoll, Christian; Wilkovitsch, Martin; Weinberger, Peter [TU Wien, Institute of Applied Synthetic Chemistry, Vienna (Austria); Giester, Gerald [University of Vienna, Institute of Mineralogy and Crystallography, Vienna (Austria); Ofner, Johannes; Lendl, Bernhard [TU Wien, Institute of Chemical Technologies and Analytics, Vienna (Austria); Steinhauser, Georg [Leibniz Universitaet Hannover, Institute of Radioecology and Radiation Protection (Germany)

2017-10-16

The crystallization of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H{sub 2}O){sub 7}ZT]{sub 2} ZT.10 H{sub 2}O is isostructural to light lanthanide (Ce-Gd) 5,5{sup '}-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5{sup '}-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H{sub 2}O){sub 8}]{sub 2}ZT{sub 3}.6 H{sub 2}O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 10{sup 8}-fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microscopy. In addition, the inclusion properties of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Solar Thermochemical Hydrogen Production via Terbium Oxide Based Redox Reactions

Directory of Open Access Journals (Sweden)

Rahul Bhosale

2016-01-01

Full Text Available The computational thermodynamic modeling of the terbium oxide based two-step solar thermochemical water splitting (Tb-WS cycle is reported. The 1st step of the Tb-WS cycle involves thermal reduction of TbO2 into Tb and O2, whereas the 2nd step corresponds to the production of H2 through Tb oxidation by water splitting reaction. Equilibrium compositions associated with the thermal reduction and water splitting steps were determined via HSC simulations. Influence of oxygen partial pressure in the inert gas on thermal reduction of TbO2 and effect of water splitting temperature (TL on Gibbs free energy related to the H2 production step were examined in detail. The cycle (ηcycle and solar-to-fuel energy conversion (ηsolar-to-fuel efficiency of the Tb-WS cycle were determined by performing the second-law thermodynamic analysis. Results obtained indicate that ηcycle and ηsolar-to-fuel increase with the decrease in oxygen partial pressure in the inert flushing gas and thermal reduction temperature (TH. It was also realized that the recuperation of the heat released by the water splitting reactor and quench unit further enhances the solar reactor efficiency. At TH=2280 K, by applying 60% heat recuperation, maximum ηcycle of 39.0% and ηsolar-to-fuel of 47.1% for the Tb-WS cycle can be attained.

Terbium(III)/gold nanocluster conjugates: the development of a novel ratiometric fluorescent probe for mercury(II) and a paper-based visual sensor.

Science.gov (United States)

Qi, Yan-Xia; Zhang, Min; Zhu, Anwei; Shi, Guoyue

2015-08-21

In this work, a novel ratiometric fluorescent probe was developed for rapid, highly accurate, sensitive and selective detection of mercury(II) (Hg(2+)) based on terbium(III)/gold nanocluster conjugates (Tb(3+)/BSA-AuNCs), in which bovine serum albumin capped gold nanoclusters (BSA-AuNCs) acted as the signal indicator and terbium(III) (Tb(3+)) was used as the build-in reference. Our proposed ratiometric fluorescent probe exhibited unique specificity toward Hg(2+) against other common environmentally and biologically important metal ions, and had high accuracy and sensitivity with a low detection limit of 1 nM. In addition, our proposed probe was effectively employed to detect Hg(2+) in the biological samples from the artificial Hg(2+)-infected rats. More significantly, an appealing paper-based visual sensor for Hg(2+) was designed by using filter paper embedded with Tb(3+)/BSA-AuNC conjugates, and we have further demonstrated its feasibility for facile fluorescent sensing of Hg(2+) in a visual format, in which only a handheld UV lamp is used. In the presence of Hg(2+), the paper-based visual sensor, illuminated by a handheld UV lamp, would undergo a distinct fluorescence color change from red to green, which can be readily observed with naked eyes even in trace Hg(2+) concentrations. The Tb(3+)/BSA-AuNC-derived paper-based visual sensor is cost-effective, portable, disposable and easy-to-use. This work unveiled a facile approach for accurate, sensitive and selective measuring of Hg(2+) with self-calibration.

Removing foxing stains from old paper at 157 nm

International Nuclear Information System (INIS)

Sarantopoulou, E.; Samardzija, Z.; Kobe, S.; Kollia, Z.; Cefalas, A.C.

2003-01-01

Using a molecular fluorine laser at 157 nm foxing stains were removed successfully from a 16th century old paper. Laser cleaning of stains and foxing from old paper manuscripts is far more effective at 157 nm in comparison to different wavelengths without leaving any yellowish after-effect on the paper. This is because at 157 nm illumination of old paper, complete bond breaking of all the organic molecules of the paper is taking place. Mass spectroscopy at 157 nm and for moderate laser intensities up to 1 mJ/cm 2 of old paper suffering from foxing indicate organic matter disintegration to small photofragments atomic, diatomic or triatomic, which are flying apart with supersonic speed. In addition high spatial resolution energy dispersive X-ray system (EDXS) analysis over the effected areas indicate the presence of iron, suggesting that biological activity is taking place preferentially in paper areas containing iron

Preparation and luminescence properties of terbium-doped lanthanum oxide nanofibers by electrospinning

Energy Technology Data Exchange (ETDEWEB)

Song Lixin; Du Pingfan [Key Laboratory of Advanced Textile Materials and Manufacturing Technology (Zhejiang Sci-Tech University), Ministry of Education, Hangzhou 310018 (China); Xiong Jie, E-mail: jxiong@zstu.edu.cn [Key Laboratory of Advanced Textile Materials and Manufacturing Technology (Zhejiang Sci-Tech University), Ministry of Education, Hangzhou 310018 (China); Fan Xiaona; Jiao Yuxue [Key Laboratory of Advanced Textile Materials and Manufacturing Technology (Zhejiang Sci-Tech University), Ministry of Education, Hangzhou 310018 (China)

2012-01-15

Terbium-doped lanthanum oxide (La{sub 2}O{sub 3}:Tb{sup 3+}) nanofibers were prepared by electrospinning followed by calcination at high temperature. Thermogravimetric analyzer (TGA), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) were used to characterize the obtained fibers. The results reveal that the nanofibers have an average diameter of ca. 95{+-}25 nm and are composed of pure La{sub 2}O{sub 3} phase. Under the excitation of 274 nm light, the La{sub 2}O{sub 3}:Tb{sup 3+} nanofibers exhibit the characteristic emission resulting from the {sup 5}D{sub 4}{yields}{sup 7}F{sub J} (J=3, 4, 5, 6) transitions of Tb{sup 3+} ions. And the PL emission intensity is stronger than that of their nanoparticle counterparts. - Highlights: > Tb{sup 3+}-doped La{sub 2}O{sub 3} (La{sub 2}O{sub 3}:Tb{sup 3+}) fluorescent nanofibers were prepared via a simple electrospinning technique. > Luminescent properties and other characteristics of the nanofibers were investigated in details. > Potential applications of La{sub 2}O{sub 3}:Tb{sup 3+} nanofibers and electrospinning technique described in this paper are suggested.

Sensitization effects of supramolecular assemblies on the luminescence of terbium-ion prulifloxacin complexes

Energy Technology Data Exchange (ETDEWEB)

Wang Hong; Yi Chongyue; Li Xue; Fang Fang [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yang Yajiang, E-mail: yjyang@mail.hust.edu.c [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2011-04-15

Luminescence enhancement of terbium-ion prulifloxacin complexes (Tb(III)-PUFX) in supramolecular hydrogels formed by assembly of 1,3:2,4-di-O-benzylidene-D-sorbitol (DBS) was investigated by steady-state fluorescence, varying temperature fluorescence and time-resolved fluorescence. The luminescence images show that Tb(III)-PUFX were dispersed in the DBS gels. The luminescence intensity of Tb(III)-PUFX in the DBS gels was significantly increased in comparison with that in corresponding aqueous solutions. The varying temperature fluorescent spectra show that the luminescence intensity of Tb(III)-PUFX decreased with an increase in the temperature. This implies that the luminescence enhancement of Tb(III)-PUFX is related to the dissociation and the formation of the DBS assemblies. Time-resolved fluorescence measurements show slower rotational motion in DBS gels in comparison with that in the corresponding aqueous solutions. This may be ascribed to a unique microstructure of three-dimensional network formed by DBC aggregates, resulting in deactivation of the nonradiative relaxation. The images of field emission scanning electron microscopy and polarized optical microscopy indicate that the morphology of the DBS assemblies was not influenced upon addition of Tb(III)-PUFX to the DBS gels.

Multiplex real-time PCR assay for detection of Escherichia coli O157:H7 and screening for non-O157 Shiga toxin-producing E. coli.

Science.gov (United States)

Li, Baoguang; Liu, Huanli; Wang, Weimin

2017-11-09

Shiga toxin-producing Escherichia coli (STEC), including E. coli O157:H7, are responsible for numerous foodborne outbreaks annually worldwide. E. coli O157:H7, as well as pathogenic non-O157:H7 STECs, can cause life-threating complications, such as bloody diarrhea (hemolytic colitis) and hemolytic-uremic syndrome (HUS). Previously, we developed a real-time PCR assay to detect E. coli O157:H7 in foods by targeting a unique putative fimbriae protein Z3276. To extend the detection spectrum of the assay, we report a multiplex real-time PCR assay to specifically detect E. coli O157:H7 and screen for non-O157 STEC by targeting Z3276 and Shiga toxin genes (stx1 and stx2). Also, an internal amplification control (IAC) was incorporated into the assay to monitor the amplification efficiency. The multiplex real-time PCR assay was developed using the Life Technology ABI 7500 System platform and the standard chemistry. The optimal amplification mixture of the assay contains 12.5 μl of 2 × Universal Master Mix (Life Technology), 200 nM forward and reverse primers, appropriate concentrations of four probes [(Z3276 (80 nM), stx1 (80 nM), stx2 (20 nM), and IAC (40 nM)], 2 μl of template DNA, and water (to make up to 25 μl in total volume). The amplification conditions of the assay were set as follows: activation of TaqMan at 95 °C for 10 min, then 40 cycles of denaturation at 95 °C for 10 s and annealing/extension at 60 °C for 60 s. The multiplex assay was optimized for amplification conditions. The limit of detection (LOD) for the multiplex assay was determined to be 200 fg of bacterial DNA, which is equivalent to 40 CFU per reaction which is similar to the LOD generated in single targeted PCRs. Inclusivity and exclusivity determinants were performed with 196 bacterial strains. All E. coli O157:H7 (n = 135) were detected as positive and all STEC strains (n = 33) were positive for stx1, or stx2, or stx1 and stx2 (Table 1). No cross reactivity was detected with Salmonella

18 CFR 157.5 - Purpose and intent of rules.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Purpose and intent of rules. 157.5 Section 157.5 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... the market contemplated by the proposed project and the nature and disposition of such other project...

Fluorometric determination of proteins using the terbium (III)-2-thenoyltrifluoroacetone-sodium dodecyl benzene sulfonate-protein system

Energy Technology Data Exchange (ETDEWEB)

Jia Zhen [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Department of Chemistry, Dezhou University, Dezhou 253023 (China); Yang Jinghe [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)]. E-mail: yjh@sdu.edu.cn; Wu Xia [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Wang Fei [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Guo Changying [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Liu Shufang [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

2006-12-15

It is found that in hexamethylene tetramine (HMTA)-HCl buffer of pH=8.00, proteins can enhance the fluorescence of terbium (III) (Tb{sup 3+})-2-thenoyltrifluoroacetone (TTA)-sodium dodecyl benzene sulfonate (SDBS) system. Based on this, a sensitive method for the determination of proteins is proposed. The experiments indicate that under the optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of proteins in the range of 4.0x10{sup -9}-7.5x10{sup -6}g/mL for bovine serum albumin (BSA), 5.0x10{sup -9}-1.5x10{sup -5}g/mL for human serum albumin (HSA), 1.0x10{sup -8}-7.5x10{sup -6}g/mL for egg albumin (EA). Their detection limits (S/N=3) are 0.5, 0.8 and 2.0ng/mL, respectively. The interaction mechanism is also studied.

Spectrofluorimetric determination of trace amount of coenzyme II using ciprofloxacin-terbium complex as a fluorescent probe

International Nuclear Information System (INIS)

Bian Weiwei; Wang Yusheng; Zhu Xiaojing; Jiang Chongqiu

2006-01-01

A new spectrofluorimetric method was developed for the determination of trace amount of nicotinamide adenine dinucleotide phosphate (NADP). Using terbium ion (Tb 3+ )-ciprofloxacin (CIP) complex as a fluorescent probe, in the buffer solution of pH=9.00, NADP can remarkably enhance the fluorescence intensity of the Tb 3+ -CIP complex at λ=545nm and the enhanced fluorescence intensity of Tb 3+ ion is in proportion to the concentration of NADP. Optimum conditions for the determination of NADP were also investigated. The dynamic range for the determination of NADP is 4.9x10 -7 -3.7x10 -6 molL -1 with detection limit of 1.3x10 -7 molL -1 . This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of NADP in synthetic water samples. Moreover, the enhancement mechanisms of the fluorescence intensity in the Tb 3+ -CIP system and the Tb 3+ -CIP-NADP system have been also discussed

33 CFR 157.148 - COW system: Evidence for inspections.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false COW system: Evidence for... CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Inspections § 157.148 COW system... inspector evidence that the COW system has been installed in accordance with the plans accepted under § 157...

9 CFR 381.157 - Canned boned poultry and baby or geriatric food.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Canned boned poultry and baby or geriatric food. 381.157 Section 381.157 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... Standards of Identity or Composition § 381.157 Canned boned poultry and baby or geriatric food. (a) Canned...

A search for long-lived radionuclides produced by fast-neutron irradiations of copper, silver, europium, terbium, and hafnium

International Nuclear Information System (INIS)

Meadows, J.W.; Smith, D.L.; Ikeda, Y.; Konno, C.

1990-01-01

Identical sample packets, each containing samples of elemental copper, silver, europium, terbium, and hafnium, as well as titanium, iron and nickel as dosimeters, have been irradiated in three distinct accelerator neutron fields (at Argonne National Laboratory and Los Alamos National Laboratory in the U.S.A., and Japan Atomic Energy Research Institute, Tokai, Japan) as part of an interlaboratory research collaboration to search for the production of long-lived radionuclides for fusion waste disposal applications. This paper is a progress report on this project. To date, we have detected the following activities, and have obtained preliminary experimental cross section values for several of these: Ag-106m,108m,110m; Eu-150m,152g,154; Tb-158,160; and Hf-175,178m2,179m2,181. (author). 11 refs, 1 fig., 4 tabs

The prevalence of Escherichia coli O157 and O157:H7 in ground beef and raw meatball by immunomagnetic separation and the detection of virulence genes using multiplex PCR.

Science.gov (United States)

Cadirci, Ozgür; Siriken, Belgin; Inat, Gökhan; Kevenk, Tahsin Onur

2010-03-01

The present study was conducted to investigate the presence of Escherichia coli O157 and O157:H7 strains and to detect the presence of the stx1, stx2, and eaeA genes in isolates derived from 200 samples (100 samples from fresh ground beef and 100 samples from raw meatball). The samples were purchased from the Samsun Province in Turkey, over a period of 1 year. Enrichment-based immunomagnetic separation and multiplex polymerase chain reaction were applied for these analyses. E. coli O157 was detected in five of the 200 (2.5%) samples tested (one isolated from ground beef and four from meatball samples), whereas E. coli O157: H7 was not detected in any sample. During the analysis, eight strains of E. coli O157 were obtained. The genes stx1, stx2, and eaeA were detected in two E. coli O157 isolates obtained from two meatball samples, whereas only the eaeA and the stx2 genes were detected in four E. coli O157 strains that were isolated from one meatball sample. None of the stx1, stx2, and eaeA was detected in the E. coli O157 isolates obtained from the ground beef and the one meatball samples. Copyright 2009 Elsevier Ltd. All rights reserved.

18 CFR 157.212 - Synthetic and liquefied natural gas facilities.

Science.gov (United States)

2010-04-01

... natural gas facilities. 157.212 Section 157.212 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER NATURAL GAS ACT APPLICATIONS FOR CERTIFICATES... 7 OF THE NATURAL GAS ACT Interstate Pipeline Blanket Certificates and Authorization Under Section 7...

the occurrence of escherichia coli o157:h7 in market and abattoir

African Journals Online (AJOL)

user

Escherichia coli O157:H7 is a newly emerging pathogen frequently associated with the consumption of foods of ... KEY WORDS: E. coli O157:H7, Pathogen, Abattoir, Market, and Infections ..... pathogen. Escherichia coli O157:H7 as a model of.

Pentadecapeptide BPC 157 Enhances the Growth Hormone Receptor Expression in Tendon Fibroblasts

Directory of Open Access Journals (Sweden)

Chung-Hsun Chang

2014-11-01

Full Text Available BPC 157, a pentadecapeptide derived from human gastric juice, has been demonstrated to promote the healing of different tissues, including skin, muscle, bone, ligament and tendon in many animal studies. However, the underlying mechanism has not been fully clarified. The present study aimed to explore the effect of BPC 157 on tendon fibroblasts isolated from Achilles tendon of male Sprague-Dawley rat. From the result of cDNA microarray analysis, growth hormone receptor was revealed as one of the most abundantly up-regulated genes in tendon fibroblasts by BPC 157. BPC 157 dose- and time-dependently increased the expression of growth hormone receptor in tendon fibroblasts at both the mRNA and protein levels as measured by RT/real-time PCR and Western blot, respectively. The addition of growth hormone to BPC 157-treated tendon fibroblasts dose- and time-dependently increased the cell proliferation as determined by MTT assay and PCNA expression by RT/real-time PCR. Janus kinase 2, the downstream signal pathway of growth hormone receptor, was activated time-dependently by stimulating the BPC 157-treated tendon fibroblasts with growth hormone. In conclusion, the BPC 157-induced increase of growth hormone receptor in tendon fibroblasts may potentiate the proliferation-promoting effect of growth hormone and contribute to the healing of tendon.

A Terbium Sensitized Luminescence Method for the Assay of Flubiprofen in Pharmaceutical Formulations

Directory of Open Access Journals (Sweden)

Salma M.Z. Al-Kindy

2014-12-01

Full Text Available A sensitive time-resolved luminescence method for the determination of flubiprofen (FLP in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+ by the formation of a ternary complex with FLP in the presence of 4,7 diphenyl 1,10 phenanthroline (DPP as co-ligand, and Tween-20 as surfactant. The signal for Tb-FLP-DPP was monitored at λex  = 285 nm and λem  = 552 nm. Optimum conditions for the formation of the complex in an aqueous system were TRIS buffer, pH 8.0, DPP (2.5Å~10−7  M, Tween-20 (0.30% and 4Å~10-5  mol L-1  of Tb3+  which allowed the determination of 20–1000 ng mL-1  of FLP with a limit of detection (LOD of 10 ng mL-1 . The relative standard deviations of the method ranged between 0.6 and 1.4% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assays of FLP in pharmaceutical formulations and spiked tap water samples with average recoveries of 87% – 95%.

The CD157-integrin partnership controls transendothelial migration and adhesion of human monocytes.

Science.gov (United States)

Lo Buono, Nicola; Parrotta, Rossella; Morone, Simona; Bovino, Paola; Nacci, Giulia; Ortolan, Erika; Horenstein, Alberto L; Inzhutova, Alona; Ferrero, Enza; Funaro, Ada

2011-05-27

CD157, a member of the CD38 gene family, is an NAD-metabolizing ectoenzyme and a signaling molecule whose role in polarization, migration, and diapedesis of human granulocytes has been documented; however, the molecular events underpinning this role remain to be elucidated. This study focused on the role exerted by CD157 in monocyte migration across the endothelial lining and adhesion to extracellular matrix proteins. The results demonstrated that anti-CD157 antibodies block monocyte transmigration and adhesion to fibronectin and fibrinogen but that CD157 cross-linking is sufficient to overcome the block, suggesting an active signaling role for the molecule. Consistent with this is the observation that CD157 is prevalently located within the detergent-resistant membrane microdomains to which, upon clustering, it promotes the recruitment of β(1) and β(2) integrin, which, in turn, leads to the formation of a multimolecular complex favoring signal transduction. This functional cross-talk with integrins allows CD157 to act as a receptor despite its intrinsic structural inability to do so on its own. Intracellular signals mediated by CD157 rely on the integrin/Src/FAK (focal adhesion kinase) pathway, resulting in increased activity of the MAPK/ERK1/2 and the PI3K/Akt downstream signaling pathways, which are crucial in the control of monocyte transendothelial migration. Collectively, these findings indicate that CD157 acts as a molecular organizer of signaling-competent membrane microdomains and that it forms part of a larger molecular machine ruled by integrins. The CD157-integrin partnership provides optimal adhesion and transmigration of human monocytes.

Search for Enterohaemorrhagic Escherichia coli O157:H7 and ...

African Journals Online (AJOL)

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 and Salmonella enterica are important zoonotic bacteria responsible for enteric infections in humans. The present study investigated the possible role of kittens in the zoonotic transmission of antimicrobial resistant EHEC O157 and Salmonella enterica to human using ...

17 CFR 1.57 - Operations and activities of introducing brokers.

Science.gov (United States)

2010-04-01

... introducing brokers. 1.57 Section 1.57 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION... introducing brokers. (a) Each introducing broker must: (1) Open and carry each customer's and option customer..., That an introducing broker which has entered into a guarantee agreement with a futures commission...

Antibiotic susceptibility-resistance profiles of super-shed Escherichia coli O157:H7

Science.gov (United States)

Introduction: Escherichia coli O157:H7 (O157) can cause diarrhea and serious secondary sequelae including kidney failure and death in humans. With antibiotics like fosfomycin, colistin and azithromycin, that do not stimulate toxin expression by O157, being considered for treatment of early gastroint...

PCR and ELISA (VIDAS ECO O157® Escherichia coli O157:H7 identification in Minas Frescal cheese commercialized in Goiânia, GO

Directory of Open Access Journals (Sweden)

Rosangela Nunes Carvalho

2014-01-01

Full Text Available Escherichia coli O157:H7 has been incriminated in food poisoning outbreaks and sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome in many countries. Considering the high susceptibility of Minas Frescal cheese to contamination by E. coli O157:H7, the aim of this study was to determine the occurrence of this pathogen through PCR (Polymerase Chain Reaction and ELISA (VIDAS ECO O157®, bioMérieux, Lyon, France test. Thirty cheese samples manufactured by artisan farmhouse producers were collected from open-air markets in Goiânia and thirty from industries under Federal Inspection located in Goiás State which trade their products in supermarkets in Goiânia. E. coli O157:H7 was detected in 6.67% samples collected in open air markets using ELISA, and 23,33% with PCR. The pathogen was not detected in samples from industries under Federal Inspection.

PCR and ELISA (VIDAS ECO O157®) Escherichia coli O157:H7 identification in Minas Frescal cheese commercialized in Goiânia, GO

Science.gov (United States)

Carvalho, Rosangela Nunes; de Oliveira, Antonio Nonato; de Mesquita, Albenones José; Minafra e Rezende, Cíntia Silva; de Mesquita, Adriano Queiroz; Romero, Rolando Alfredo Mazzoni

2014-01-01

Escherichia coli O157:H7 has been incriminated in food poisoning outbreaks and sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome in many countries. Considering the high susceptibility of Minas Frescal cheese to contamination by E. coli O157:H7, the aim of this study was to determine the occurrence of this pathogen through PCR (Polymerase Chain Reaction) and ELISA (VIDAS ECO O157®, bioMérieux, Lyon, France) test. Thirty cheese samples manufactured by artisan farmhouse producers were collected from open-air markets in Goiânia and thirty from industries under Federal Inspection located in Goiás State which trade their products in supermarkets in Goiânia. E. coli O157:H7 was detected in 6.67% samples collected in open air markets using ELISA, and 23,33% with PCR. The pathogen was not detected in samples from industries under Federal Inspection. PMID:24948907

Evidence of mass exchange between inside and outside of sonoluminescing bubble in aqueous solution of terbium chloride

Energy Technology Data Exchange (ETDEWEB)

Liang, Jinfu, E-mail: liang.shi2007@163.com [School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550001 (China); Chen, Weizhong, E-mail: wzchen@nju.edu.cn [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China); Wang, Xun; Yang, Jing; Chen, Zhan [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China)

2016-12-16

Highlights: • Time-resolved spectra of SBSL were obtained for Tb{sup 3+} ions emission lines. • Mass exchange between inside and outside of SL bubble was probed via Tb{sup 3+} ions lines. • The argon rectification hypothesis was tested by time-resolved spectra of SBSL. • The rate of mass exchange inside an SBSL bubble increases with increasing sound pressure. - Abstract: Spectra of single-bubble sonoluminescence (SBSL) were obtained for Tb{sup 3+} ions emission lines from bubbles in an aqueous solution of terbium chloride (TbCl{sub 3}). The spectra provide experimental evidence to prove that an air bubble driven by strong ultrasound will not eventually become a rectified pure argon bubble, which is not as predicted by the argon rectification hypothesis. The time-resolved spectra of SBSL show a mass exchange of material such as Tb{sup 3+} ions between the inside and outside of the bubble. With increasing sound pressure, the rate of mass exchange and the SBSL intensity increases.

The CD157-Integrin Partnership Controls Transendothelial Migration and Adhesion of Human Monocytes*

Science.gov (United States)

Lo Buono, Nicola; Parrotta, Rossella; Morone, Simona; Bovino, Paola; Nacci, Giulia; Ortolan, Erika; Horenstein, Alberto L.; Inzhutova, Alona; Ferrero, Enza; Funaro, Ada

2011-01-01

CD157, a member of the CD38 gene family, is an NAD-metabolizing ectoenzyme and a signaling molecule whose role in polarization, migration, and diapedesis of human granulocytes has been documented; however, the molecular events underpinning this role remain to be elucidated. This study focused on the role exerted by CD157 in monocyte migration across the endothelial lining and adhesion to extracellular matrix proteins. The results demonstrated that anti-CD157 antibodies block monocyte transmigration and adhesion to fibronectin and fibrinogen but that CD157 cross-linking is sufficient to overcome the block, suggesting an active signaling role for the molecule. Consistent with this is the observation that CD157 is prevalently located within the detergent-resistant membrane microdomains to which, upon clustering, it promotes the recruitment of β1 and β2 integrin, which, in turn, leads to the formation of a multimolecular complex favoring signal transduction. This functional cross-talk with integrins allows CD157 to act as a receptor despite its intrinsic structural inability to do so on its own. Intracellular signals mediated by CD157 rely on the integrin/Src/FAK (focal adhesion kinase) pathway, resulting in increased activity of the MAPK/ERK1/2 and the PI3K/Akt downstream signaling pathways, which are crucial in the control of monocyte transendothelial migration. Collectively, these findings indicate that CD157 acts as a molecular organizer of signaling-competent membrane microdomains and that it forms part of a larger molecular machine ruled by integrins. The CD157-integrin partnership provides optimal adhesion and transmigration of human monocytes. PMID:21478153

Determination of the Thermal Inactivation Kinetics of Listeria monocytogenes, Salmonella enterica, and Escherichia coli O157:H7 and non-O157 in Buffer and a Spinach Homogenate.

Science.gov (United States)

Monu, Emefa Angelica; Valladares, Malcond; D'Souza, Doris H; Davidson, P Michael

2015-08-01

Produce has been associated with a rising number of foodborne illness outbreaks. While much produce is consumed raw, some is treated with mild heat, such as blanching or cooking. The objectives of this research were to compare the thermal inactivation kinetics of Listeria monocytogenes, Salmonella enterica, Shiga toxin-producing Escherichia coli (STEC) O157:H7, and non-O157 STEC in phosphate-buffered saline (PBS; pH 7.2) and a spinach homogenate and to provide an estimate of the safety of mild heat processes for spinach. Five individual strains of S. enterica, L. monocytogenes, STEC O157:H7, and non-O157 STEC were tested in PBS in 2-ml glass vials, and cocktails of the organisms were tested in blended spinach in vacuum-sealed bags. For Listeria and Salmonella at 56 to 60°C, D-values in PBS ranged from 4.42 ± 0.94 to 0.35 ± 0.03 min and 2.11 ± 0.14 to 0.16 ± 0.03 min, respectively. D-values at 54 to 58°C were 5.18 ± 0.21 to 0.53 ± 0.04 min for STEC O157:H7 and 5.01 ± 0.60 to 0.60 ± 0.13 min for non-O157 STEC. In spinach at 56 to 60°C, Listeria D-values were 11.77 ± 2.18 to 1.22 ± 0.12 min and Salmonella D-values were 3.51 ± 0.06 to 0.47 ± 0.06 min. D-values for STEC O157:H7 and non-O157 STEC were 7.21 ± 0.17 to 1.07 ± 0.11 min and 5.57 ± 0.38 to 0.99 ± 0.07 min, respectively, at 56 to 60°C. In spinach, z-values were 4.07 ± 0.16, 4.59 ± 0.26, 4.80 ± 0.92, and 5.22 ± 0.20°C for Listeria, Salmonella, STEC O157:H7, and non-O157 STEC, respectively. Results indicated that a mild thermal treatment of blended spinach at 70°C for less than 1 min would result in a 6-log reduction of all pathogens tested. These findings may assist the food industry in the design of suitable mild thermal processes to ensure food safety.

ADP ribosyl-cyclases (CD38/CD157), social skills and friendship.

Science.gov (United States)

Chong, Anne; Malavasi, Fabio; Israel, Salomon; Khor, Chiea Chuen; Yap, Von Bing; Monakhov, Mikhail; Chew, Soo Hong; Lai, Poh San; Ebstein, Richard P

2017-04-01

Why some individuals seek social engagement while others shy away has profound implications for normal and pathological human behavior. Evidence suggests that oxytocin (OT), the paramount human social hormone, and CD38 that governs OT release, contribute to individual differences in social skills from intense social involvement to extreme avoidance that characterize autism. To explore the neurochemical underpinnings of sociality, CD38 expression of peripheral blood leukocytes (PBL) was measured in Han Chinese undergraduates. First, CD38 mRNA levels were correlated with lower Autism Quotient (AQ), indicating enhanced social skills. AQ assesses the extent of autistic-like traits including the propensity and dexterity needed for successful social engagement in the general population. Second, three CD157 eQTL SNPs in the CD38/CD157 gene region were associated with CD38 expression. CD157 is a paralogue of CD38 and is contiguous with it on chromosome 4p15. Third, association was also observed between the CD157 eQTL SNPs, CD38 expression and AQ. In the full model, CD38 expression and CD157 eQTL SNPs altogether account for a substantial 14% of the variance in sociality. Fourth, functionality of CD157 eQTL SNPs was suggested by a significant association with plasma oxytocin immunoreactivity products. Fifth, the ecological validity of these findings was demonstrated with subjects with higher PBL CD38 expression having more friends, especially for males. Furthermore, CD157 sequence variation predicts scores on the Friendship questionnaire. To summarize, this study by uniquely leveraging various measures reveals salient elements contributing to nonkin sociality and friendship, revealing a likely pathway underpinning the transition from normality to psychopathology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Persistence of Escherichia coli O157:H7 in dairy fermentation systems.

Science.gov (United States)

Dineen, S S; Takeuchi, K; Soudah, J E; Boor, K J

1998-12-01

We examined (i) the persistence of Escherichia coli O157:H7 as a postpasteurization contaminant in fermented dairy products; (ii) the ability of E. coli O157:H7 strains with and without the general stress regulatory protein, RpoS, to compete with commercial starter cultures in fermentation systems; and (iii) the survival of E. coli O157:H7 in the yogurt production process. In commercial products inoculated with 10(3) CFU/ml, E. coli O157:H7 was recovered for up to 12 days in yogurt (pH 4.0), 28 days in sour cream (pH 4.3), and at levels > 10(2) CFU/ml at 35 days in buttermilk (pH 4.1). For the starter culture competition trials, the relative inhibition of E. coli O157:H7 in the experimental fermentation systems was, in decreasing order, thermophilic culture mixture, Lactobacillus delbrueckii subsp. bulgaricus R110 alone, Lactococcus lactis subsp. lactis D280 alone, Lactococcus lactis subsp. cremoris D62 alone, and Streptococcus thermophilus C90 alone showing the least inhibition. Recovery of the rpoS mutant was lower than recovery of its wild-type parent by 72 h or earlier in the presence of individual starter cultures. No E. coli O157:H7 were recovered after the curd formation step in yogurt manufactured with milk inoculated with 10(5) CFU/ml. Our results show that (i) postprocessing entry of E. coli O157:H7 into fermented dairy products represents a potential health hazard; (ii) commercial starter cultures differ in their ability to reduce E. coli O157:H7 CFU numbers in fermentation systems; and (iii) the RpoS protein appears to most effectively contribute to bacterial survival in the presence of conditions that are moderately lethal to the cell.

High power single-frequency and frequency-doubled laser with active compensation for the thermal lens effect of terbium gallium garnet crystal.

Science.gov (United States)

Yin, Qiwei; Lu, Huadong; Su, Jing; Peng, Kunchi

2016-05-01

The thermal lens effect of terbium gallium garnet (TGG) crystal in a high power single-frequency laser severely limits the output power and the beam quality of the laser. By inserting a potassium dideuterium phosphate (DKDP) slice with negative thermo-optical coefficient into the laser resonator, the harmful influence of the thermal lens effect of the TGG crystal can be effectively mitigated. Using this method, the stable range of the laser is broadened, the bistability phenomenon of the laser during the process of changing the pump power is completely eliminated, the highest output power of an all-solid-state continuous-wave intracavity-frequency-doubling single-frequency laser at 532 nm is enhanced to 30.2 W, and the beam quality of the laser is significantly improved.

20 CFR 655.157 - Withholding of U.S. workers prohibited.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Withholding of U.S. workers prohibited. 655.157 Section 655.157 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR... of H-2A workers in order to force the hiring of U.S. workers during the recruitment period, as set...

Effect of solvents on relation of intensities of bands of luminescence spectra of terbium and dysprosium ions in solutions of their complexes with acetoacetic ester

International Nuclear Information System (INIS)

Kononenko, L.I.; Bel'tyukova, S.V.; Meshkova, S.B.; Kravchenko, T.B.; Poluehktov, N.S.

1978-01-01

An investigation is made of the effect of different solvents on the ratio of the intensity of luminescence spectrum bands of terbium and dysprosium ions, corresponding and not corresponding to ''supersensitive'' transitions in complex compounds with acetoacetic ether. A dependence is established between these values and the dielectric constant of the solvent, and also parallels in their changes, which indicate the similar manifestation of the effect of solvents in both elements. A correlation is observed between ratios of the intensity of luminescence spectrum bands and values of forces of neodymium complex absorption band oscillators in different solvents

Synthesis and characterization of bright green terbium coordination complex derived from 1,4-bis(carbonylmethyl)terephthalate: Structure and luminescence properties

Science.gov (United States)

Ma, Mengjiao; Li, Congcong; Shu, Dengkun; Wang, Chaohua; Xi, Peng

2018-02-01

A photoluminescent terbium (Tb) complex involving a novel benzoic-acid compound with a unique coordinated structure, namely 1,4-bis(carbonylmethyl)terephthalate (BCMT), has been designed and synthesized. The new coordinate structure and energy-transfer mechanism between the ligand and Tb(III) ions were investigated in detail. The results demonstrated that the BCMT-Tb(III) complex shows strong fluorescence intensity (4 × 106 a.u.) and long fluorescence lifetime (1.302 ms), owing to the favorable degree of energy matching between the triplet excited level of the ligand and the resonant level of Tb(III) ions. Based on the analysis of three-dimensional luminescence spectra, the as-prepared Tb(III) complex can be effectively excited in the range of 250-310 nm, and it shows high color purity, with a bright green appearance.

Escherichia coli O157:H7: Animal Reservoir and Sources of Human Infection

Science.gov (United States)

Ferens, Witold A.

2011-01-01

Abstract This review surveys the literature on carriage and transmission of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in the context of virulence factors and sampling/culture technique. EHEC of the O157:H7 serotype are worldwide zoonotic pathogens responsible for the majority of severe cases of human EHEC disease. EHEC O157:H7 strains are carried primarily by healthy cattle and other ruminants, but most of the bovine strains are not transmitted to people, and do not exhibit virulence factors associated with human disease. Prevalence of EHEC O157:H7 is probably underestimated. Carriage of EHEC O157:H7 by individual animals is typically short-lived, but pen and farm prevalence of specific isolates may extend for months or years and some carriers, designated as supershedders, may harbor high intestinal numbers of the pathogen for extended periods. The prevalence of EHEC O157:H7 in cattle peaks in the summer and is higher in postweaned calves and heifers than in younger and older animals. Virulent strains of EHEC O157:H7 are rarely harbored by pigs or chickens, but are found in turkeys. The bacteria rarely occur in wildlife with the exception of deer and are only sporadically carried by domestic animals and synanthropic rodents and birds. EHEC O157:H7 occur in amphibian, fish, and invertebrate carriers, and can colonize plant surfaces and tissues via attachment mechanisms different from those mediating intestinal attachment. Strains of EHEC O157:H7 exhibit high genetic variability but typically a small number of genetic types predominate in groups of cattle and a farm environment. Transmission to people occurs primarily via ingestion of inadequately processed contaminated food or water and less frequently through contact with manure, animals, or infected people. PMID:21117940

Stable gastric pentadecapeptide BPC 157 heals rat colovesical fistula.

Science.gov (United States)

Grgic, Tihomir; Grgic, Dora; Drmic, Domagoj; Sever, Anita Zenko; Petrovic, Igor; Sucic, Mario; Kokot, Antonio; Klicek, Robert; Sever, Marko; Seiwerth, Sven; Sikiric, Predrag

2016-06-05

To establish the effects of BPC 157 on the healing of rat colovesical fistulas, Wistar Albino male rats were randomly assigned to different groups. BPC 157, a stable gastric pentadecapeptide, has been used in clinical applications-specifically, in ulcerative colitis-and was successful in treating both external and internal fistulas. BPC 157 was provided daily, perorally, in drinking water (10µg/kg, 12ml/rat/day) until sacrifice or, alternatively, 10µg/kg or 10ng/kg intraperitoneally, with the first application at 30min after surgery and the last at 24h before sacrifice. Controls simultaneously received an equivolume of saline (5.0ml/kg ip) or water only (12ml/rat/day). Assessment (i.e., colon and vesical defects, fistula leaking, fecaluria and defecation through the fistula, adhesions and intestinal obstruction as healing processes) took place on days 7, 14 and 28. Control colovesical fistulas regularly exhibited poor healing, with both of the defects persisting; continuous fistula leakage; fecaluria and defecation through the fistula; advanced adhesion formation; and intestinal obstruction. By contrast, BPC 157 given perorally or intraperitoneally and in µg- and ng-regimens rapidly improved the whole presentation, with both colon and vesical defects simultaneously ameliorated and eventually healed. The maximal instilled volume was continuously raised until it reached the values of healthy rats, there were no signs of fecaluria and no defecation through the fistula, there was counteraction of advanced adhesion formation or there was an intestinal obstruction. In conclusion, BPC 157 effects appear to be suited to inducing full healing of colocutaneous fistulas in rats. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification of protozoa in dairy lagoon wastewater that consume Escherichia coli O157:H7 preferentially.

Directory of Open Access Journals (Sweden)

Subbarao V Ravva

Full Text Available Escherichia coli O157:H7 (EcO157, an agent of life threatening hemolytic-uremic syndrome, resides in ruminants and is released in feces at numbers as high as 10 million cells/gram. EcO157 could survive in manure for as long as 21 months, but we observed a 90% decrease in cells of an outbreak strain of EcO157 within half a day in wastewater from dairy lagoons. Although chemical, environmental and biological factors may be responsible for this decrease, we observed an 11-fold increase in native protozoa when wastewater was re-inoculated with 2×10(7 cells of EcO157/mL. These protozoa engulfed the green fluorescent protein labeled EcO157 within 2 hours after inoculation, but expelled vacuoles filled with live EcO157 cells within 3 days into surrounding wastewater, whereas other protozoa retained the EcO157-filled vacuoles for 7 days. EcO157 was not detected by confocal microscopy either inside or outside protozoa after 7 days. Mixed cultures of protozoa enriched from wastewater consumed EcO157 preferentially as compared to native aerobic bacteria, but failed to eliminate them when EcO157 cells declined to 10(4/mL. We isolated three protozoa from mixed cultures and typed them by 18S sequencing as Vorticella microstoma, Platyophyra sp. and Colpoda aspera. While all three protozoa internalized EcO157, only Platyophyra and Colpoda acted as predators. Similar to mixed cultures, these protozoa failed to eliminate EcO157 from PBS containing no other supplemental nutrients or prey. However, spiking PBS with cereal grass medium as nutrients induced predation of EcO157 by Platyophyra sp. after 3 days or enhanced predation by Colpoda after 5 days. Therefore, attempts to enrich protozoa to decrease EcO157 from dairy lagoons, may correspond to an increase in protozoa similar to Vorticella and possibly facilitate transport of bacterial pathogens to food crops grown in proximity.

26 CFR 157.5891-1 - Imposition of excise tax on structured settlement factoring transactions.

Science.gov (United States)

2010-04-01

... settlement factoring transactions. 157.5891-1 Section 157.5891-1 Internal Revenue INTERNAL REVENUE SERVICE... SETTLEMENT FACTORING TRANSACTIONS Tax on Structured Settlement Factoring Transactions § 157.5891-1 Imposition of excise tax on structured settlement factoring transactions. (a) In general. Section 5891 imposes...

33 CFR 157.152 - Person in charge of COW operations.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Person in charge of COW... CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Personnel § 157.152 Person in charge of COW operations. The owner, operator, and master of a tank vessel having a COW system under § 157.10(e...

Prevalence and antibiogram of Escherichia coli O157 isolated from ...

African Journals Online (AJOL)

E. coli O157 is an important serotype that caused many food borne outbreaks worldwide in the past decades. This study was carried out to estimate the prevalence and determine the antimicrobial susceptibility of E. coli O157 isolated from bovine carcasses and cecal contents at one abattoir in Jimma. A total of 300 samples ...

Vaccination with killed whole-cells of Escherichia coli O157:H7 hha mutant emulsified with an adjuvant induced vaccine strain-specific serum antibodies and reduced E. coli O157:H7 fecal shedding in cattle

Science.gov (United States)

Escherichia coli O157:H7 (O157) can cause from a mild diarrheal illness to hemorrhagic colitis and hemolytic uremic syndrome in humans. Cattle are the primary reservoir for O157 and fecal shedding of O157 by these animals is a major risk factor in contamination of cattle hides and carcasses at slaug...

British Escherichia coli O157 in Cattle Study (BECS): to determine the prevalence of E. coli O157 in herds with cattle destined for the food chain.

Science.gov (United States)

Henry, M K; Tongue, S C; Evans, J; Webster, C; McKENDRICK, I J; Morgan, M; Willett, A; Reeves, A; Humphry, R W; Gally, D L; Gunn, G J; Chase-Topping, M E

2017-11-01

Escherichia coli O157 are zoonotic bacteria for which cattle are an important reservoir. Prevalence estimates for E. coli O157 in British cattle for human consumption are over 10 years old. A new baseline is needed to inform current human health risk. The British E. coli O157 in Cattle Study (BECS) ran between September 2014 and November 2015 on 270 farms across Scotland and England & Wales. This is the first study to be conducted contemporaneously across Great Britain, thus enabling comparison between Scotland and England & Wales. Herd-level prevalence estimates for E. coli O157 did not differ significantly for Scotland (0·236, 95% CI 0·166-0·325) and England & Wales (0·213, 95% CI 0·156-0·283) (P = 0·65). The majority of isolates were verocytotoxin positive. A higher proportion of samples from Scotland were in the super-shedder category, though there was no difference between the surveys in the likelihood of a positive farm having at least one super-shedder sample. E. coli O157 continues to be common in British beef cattle, reaffirming public health policy that contact with cattle and their environments is a potential infection source.

Commercializing potassium terbium fluoride, KTF (KTb3F10) faraday crystals for high laser power optical isolator applications

Science.gov (United States)

Schlichting, Wolfgang; Stevens, Kevin; Foundos, Greg; Payne, Alexis

2017-10-01

Many scientific lasers and increasingly industrial laser systems operate in manufacture. However, for high-power laser applications TGG is limited by its absorption at 1064nm and its thermo-optic coefficient, dn/dT. Specifically, thermal lensing and depolarization effects become a limiting factor at high laser powers. While TGG absorption has improved significantly over the past few years, there is an intrinsic limit. Now, SYNOPTICS is commercializing the enhanced new crystal Potassium Terbium Fluoride KTF (KTb3F10) that exhibits much smaller nonlinear refractive index and thermo-optic coefficients, and still exhibits a Verdet constant near that of TGG. This cubic crystal has relatively low absorption and thermo-optic coefficients. It is now fully characterized and available for select production orders. At OPTIFAB in October 2017 we present recent results comparing the performance of KTF to TGG in optical isolators and show SYNOPTICS advances in large volume crystal growth and the production ramp up.

The new 157Tm isotope, Tsub(1/2)=(3.6+-0.3) min

International Nuclear Information System (INIS)

Latuszynski, A.; Mikulski, J.; Potempa, A.W.; Zielinski, A.; Zuber, K.; Penev, I.; Zuber, J.

1975-01-01

The new isotope 157 Tm was discovered, and its half-life Tsub(1/2) (3.6+-0.3)min was measured. On the basis of the balance of energies and intensities of γ-transitions occurring in the 157 Tm decay a number of excited states of the 157 Er nucleus with energies of 110.2; 241.3; 357.3 and 457.1 keV were found. (author)

18 CFR 157.8 - Acceptance for filing or rejection of applications.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Acceptance for filing or rejection of applications. 157.8 Section 157.8 Conservation of Power and Water Resources FEDERAL..., the Director of the Office of Energy Projects or the Director of the Office of Energy Market...

Shiga toxin-producing Escherichia coli in Central Greece: prevalence and virulence genes of O157:H7 and non-O157 in animal feces, vegetables, and humans.

Science.gov (United States)

Pinaka, O; Pournaras, S; Mouchtouri, V; Plakokefalos, E; Katsiaflaka, A; Kolokythopoulou, F; Barboutsi, E; Bitsolas, N; Hadjichristodoulou, C

2013-11-01

In Greece, Shiga toxin-producing Escherichia coli (STEC) have only been sporadically reported. The objective of this study was to estimate the prevalence of STEC and Escherichia coli O157:H7 in farm animals, vegetables, and humans in Greece. A total number of 1,010 fecal samples were collected from farm animals (sheep, goats, cattle, chickens, pigs), 667 diarrheal samples from humans, and 60 from vegetables, which were cultured in specific media for STEC isolates. Enzyme-linked immunosorbent assay (ELISA) was used to detect toxin-producing colonies, which, subsequently, were subjected to a multiplex polymerase chain reaction (PCR) for stx1, stx2, eae, rfbE O157, and fliC h7 genes. Eighty isolates (7.9 %) from animal samples were found to produce Shiga toxin by ELISA, while by PCR, O157 STEC isolates were detected from 8 (0.8 %) samples and non-O157 STEC isolates from 43 (4.2 %) samples. STEC isolates were recovered mainly from sheep and goats, rarely from cattle, and not from pigs and chickens, suggesting that small ruminants constitute a potential risk for human infections. However, only three human specimens (0.4 %) were positive for the detection of Shiga toxins and all were PCR-negative. Similarly, all 60 vegetable samples were negative for toxin production and for toxin genes, but three samples (two roman rockets and one spinach) were positive by PCR for rfbE O157 and fliC h7 genes. These findings indicate that sheep, goats, cattle, and leafy vegetables can be a reservoir of STEC and Escherichia coli O157:H7 isolates in Greece, which are still rarely detected among humans.

Ectoenzymes and innate immunity: the role of human CD157 in leukocyte trafficking.

Science.gov (United States)

Funaro, Ada; Ortolan, Erika; Bovino, Paola; Lo Buono, Nicola; Nacci, Giulia; Parrotta, Rossella; Ferrero, Enza; Malavasi, Fabio

2009-01-01

CD157 is a glycosylphosphatidylinositol-anchored molecule encoded by a member of the CD38/ADP-ribosyl cyclase gene family, involved in the metabolism of NAD. Expressed mainly by cells of the myeloid lineage and by vascular endothelial cells, CD157 has a dual nature behaving both as an ectoenzyme and as a receptor. Although it lacks a cytoplasmic domain, and cannot transduce signals on its own, the molecule compensates for this structural limit by interacting with conventional receptors. Recent experimental evidence suggests that CD157 orchestrates critical functions of human neutrophils. Indeed, CD157-mediated signals promote cell polarization, regulate chemotaxis induced through the high affinity fMLP receptor and control transendothelial migration.

33 CFR 157.435 - Vital systems surveys.

Science.gov (United States)

2010-07-01

...) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Interim Measures for Certain Tank Vessels Without Double Hulls Carrying Petroleum Oils § 157.435 Vital...

The Escherichia coli O157:H7 bovine rumen fluid proteome reflects adaptive bacterial responses.

Science.gov (United States)

Kudva, Indira T; Stanton, Thaddeus B; Lippolis, John D

2014-02-21

To obtain insights into Escherichia coli O157:H7 (O157) survival mechanisms in the bovine rumen, we defined the growth characteristics and proteome of O157 cultured in rumen fluid (RF; pH 6.0-7.2 and low volatile fatty acid content) obtained from rumen-fistulated cattle fed low protein content "maintenance diet" under diverse in vitro conditions. Bottom-up proteomics (LC-MS/MS) of whole cell-lysates of O157 cultured under anaerobic conditions in filter-sterilized RF (fRF; devoid of normal ruminal microbiota) and nutrient-depleted and filtered RF (dRF) resulted in an anaerobic O157 fRF-and dRF-proteome comprising 35 proteins functionally associated with cell structure, motility, transport, metabolism and regulation, but interestingly, not with O157 virulence. Shotgun proteomics-based analysis using isobaric tags for relative and absolute quantitation used to further study differential protein expression in unfiltered RF (uRF; RF containing normal rumen microbial flora) complemented these results. Our results indicate that in the rumen, the first anatomical compartment encountered by this human pathogen within the cattle gastrointestinal tract (GIT), O157 initiates a program of specific gene expression that enables it to adapt to the in vivo environment, and successfully transit to its colonization sites in the bovine GIT. Further experiments in vitro using uRF from animals fed different diets and with additional O157 strains, and in vivo using rumen-fistulated cattle will provide a comprehensive understanding of the adaptive mechanisms involved, and help direct evolution of novel modalities for blocking O157 infection of cattle.

27 CFR 19.157 - Operating permits.

Science.gov (United States)

2010-04-01

... OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Qualification of Distilled Spirits Plants § 19.157... file an application for registration under § 19.151 shall make application for and obtain an operating permit before commencing any of the following operations: (1) Distilling for industrial use. (2...

Recto-anal junction (RAJ) microbiota composition in Escherichia coli O157:H7 shedding cattle

Science.gov (United States)

Introduction: Cattle are the asymptomatic reservoirs of Escherichia coli O157:H7 (O157) that tend to preferentially colonize the bovine recto-anal junction (RAJ). Therefore, understanding the taxonomic profile, microbial diversity, and microbiota-O157 interactions at the RAJ could give insights into...

33 CFR 157.150 - Crude Oil Washing Operations and Equipment Manual: Recording information after inspections.

Science.gov (United States)

2010-07-01

... Equipment Manual: Recording information after inspections. 157.150 Section 157.150 Navigation and Navigable... Vessels Inspections § 157.150 Crude Oil Washing Operations and Equipment Manual: Recording information... machines. (2) Revolutions, number of cycles, and length of cycles of each COW machine. (3) Pressure and...

Antibioticumresistentie in Escherichia coli O 157 geisoleerd tussen 1998 en 2003 in Nederland = Antibiotic resistance in Escherichia coli O157 isolated between 1998 and 2003 in The Netherlands

NARCIS (Netherlands)

Roest, H.I.J.; Liebana, E.; Wannet, W.; Duynhoven, van Y.; Veldman, K.T.; Mevius, D.J.

2007-01-01

Nederlands: Over het vóórkomen van antibioticumresistentie bij E. coli O157 in Nederland is weinig bekend. In deze studie werden tussen 1998 en 2003 218 humane en 247 niethumane isolaten onderzocht op antibioticumgevoeligheid. Het antibioticumresistentieniveau van E. coli O157 geïsoleerd uit de

Microbiota response to Escherichia coli O157:H7 colonization in cattle

Science.gov (United States)

Cattle are primary reservoir of Shiga toxin-producing Escherichia coli (STEC). Field studies indicate STEC colonization influences gut microbiota composition in beef and dairy cattle. In this pilot study, we evaluated the bovine gut microbiota after STEC O157 (O157) challenge under experimental con...

Enrichment of gadolinium-157 and gadolinium-155 by laser method

International Nuclear Information System (INIS)

Xinjun, Su; Xiaowei, Zhang; Zhiquan, Li

2008-01-01

Laser isotope separation experiments of gadolinium by atomic vapor method have been performed. Gadolinium-157 and gadolinium-155 were selectively photoionized by means of three linearly polarized dye lasers, the excitation process of which is based on the polarization selection rules. Gramme-magnitude of enriched gadolinium was obtained and the total abundance of gadolinium-157 and gadolinium-155 was in excess of 80%, and the product rating exceeded 200 mg/h. (author)

Molecular Orientation of a Terbium(III)-Phthalocyaninato Double-Decker Complex for Effective Suppression of Quantum Tunneling of the Magnetization.

Science.gov (United States)

Yamabayashi, Tsutomu; Katoh, Keiichi; Breedlove, Brian K; Yamashita, Masahiro

2017-06-15

Single-molecule magnet (SMM) properties of crystals of a terbium(III)-phthalocyaninato double-decker complex with different molecular packings ( 1 : TbPc₂, 2 : TbPc₂·CH₂Cl₂) were studied to elucidate the relationship between the molecular packing and SMM properties. From single crystal X-ray analyses, the high symmetry of the coordination environment of 2 suggested that the SMM properties were improved. Furthermore, the shorter intermolecular Tb-Tb distance and relative collinear alignment of the magnetic dipole in 2 indicated that the magnetic dipole-dipole interactions were stronger than those in 1 . This was confirmed by using direct current magnetic measurements. From alternating current magnetic measurements, the activation energy for spin reversal for 1 and 2 were similar. However, the relaxation time for 2 is three orders of magnitude slower than that for 1 in the low- T region due to effective suppression of the quantum tunneling of the magnetization. These results suggest that the SMM properties of TbPc₂ highly depend on the molecular packing.

Effect of heat treatment on the survival of Escherichia Coli O157:H7 ...

African Journals Online (AJOL)

The survival of Escherichia coli O157:H7 in raw milk treated in experimental pasteurizer was investigated in the year 2010. Raw milk was inoculated with different initial concentrations of E. coli O157:H7 and heated for 15 seconds at temperatures ranging from 69OC to 73OC. E. coli O157:H7 cells were not isolated from the ...

The Escherichia coli O157:H7 bovine rumen fluid proteome reflects adaptive bacterial responses

OpenAIRE

Kudva, Indira T; Stanton, Thaddeus B; Lippolis, John D

2014-01-01

Background To obtain insights into Escherichia coli O157:H7 (O157) survival mechanisms in the bovine rumen, we defined the growth characteristics and proteome of O157 cultured in rumen fluid (RF; pH 6.0-7.2 and low volatile fatty acid content) obtained from rumen-fistulated cattle fed low protein content “maintenance diet” under diverse in vitro conditions. Results Bottom-up proteomics (LC-MS/MS) of whole cell-lysates of O157 cultured under anaerobic conditions in filter-sterilized RF (fRF; d...

Escherichia coli O157:H7 - An Emerging Pathogen in foods of Animal Origin

Directory of Open Access Journals (Sweden)

Ch. Bindu Kiranmayi

Full Text Available Escherichia coli O157:H7 is an emerging public health concern in most countries of the world. E. coli O157:H7 was known to be a human pathogen for nearly 24 years. EHEC O157 infection is estimated to be the fourth most costly food borne disease in Canada and USA, not counting the cost of possible litigation. E. coli O157:H7 and Salmonella are the leading causes of produce related outbreaks, accounting for 20 and 30% respectively. The authority of the Federal Meat Inspection Act, FSIS (Food Safety and Inspection Service declared Escherichia coli O157:H7, an adulterant in raw ground beef and enforced “zero tolerance” (USDA-FSIS, 17 December 1998. Because of the severity of these illnesses and the apparent low infective dose (less than 10 cells, Escherichia coli O157:H7 is considered one of the most serious of known food borne pathogens. Escherichia coli O157:H7 is mainly pathogenic to human but in cattle and other animals, it did not induce any clinical disease except diarrhea. So, these animals act as carriers to Escherichia coli O157:H7. The majority transmission is through eating of undercooked contaminated ground meat and consumption of raw milk, raw vegetables, fruits contaminated by water, cheese, curd and also through consumption of sprouts, lettuce and juice. The conventional isolation procedure includes growth in enrichment broth like modified EC (E. coli broth or modified tryptic soy broth (mTSB Since the infection primarily occurs via faeco-oral route, the preventive measures include food hygiene measures like proper cooking of meat, consumption of pasteurized milk, washing fruits and vegetables especially those to be eaten raw and drinking chlorine treated water and personnel hygiene measures like washing hands after toilet visits. [Veterinary World 2010; 3(8.000: 382-389

33 CFR 157.610 - Operational measures.

Science.gov (United States)

2010-07-01

...) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Interim Measures for Certain Tank Vessels Without Double Hulls Carrying Other Non-Petroleum Oil § 157.610 Operational measures. An owner or operator of a tank vessel that carries other non-petroleum oil in bulk as...

Temperature-Dependent Fermentation of d-Sorbitol in Escherichia coli O157:H7

OpenAIRE

Bouvet, O. M. M.; Pernoud, S.; Grimont, P. A. D.

1999-01-01

The influence of growth temperature on the ability to ferment d-sorbitol was investigated in Escherichia coli O157:H7. It was found that O157:H7 strains have a temperature-sensitive sorbitol phenotype. d-Sorbitol transport and sorbitol-6-phosphate dehydrogenase activities were expressed in sorbitol-fermenting cells grown at 30°C but only at a low level at 40°C. Sorbitol-positive variants able to transport d-sorbitol were easily selected at 30°C from culture of Sor− E. coli O157:H7 strains.

Growth of Escherichia coli O157:H7, Non-O157 Shiga Toxin-Producing Escherichia coli , and Salmonella in Water and Hydroponic Fertilizer Solutions.

Science.gov (United States)

Shaw, Angela; Helterbran, Kara; Evans, Michael R; Currey, Christopher

2016-12-01

The desire for local, fresh produce year round is driving the growth of hydroponic growing systems in the United States. Many food crops, such as leafy greens and culinary herbs, grown within hydroponics systems have their root systems submerged in recirculating nutrient-dense fertilizer solutions from planting through harvest. If a foodborne pathogen were introduced into this water system, the risk of contamination to the entire crop would be high. Hence, this study was designed to determine whether Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli , and Salmonella were able to survive and reproduce in two common hydroponic fertilizer solutions and in water or whether the bacteria would be killed or suppressed by the fertilizer solutions. All the pathogens grew by 1 to 6 log CFU/ml over a 24-h period, depending on the solution. E. coli O157:H7 reached higher levels in the fertilizer solution with plants (3.12 log CFU/ml), whereas non-O157 Shiga toxin-producing E. coli and Salmonella reached higher levels in the fertilizer solution without plants (1.36 to 3.77 log CFU/ml). The foodborne pathogens evaluated here survived for 24 h in the fertilizer solution, and populations grew more rapidly in these solutions than in plain water. Therefore, human pathogens entering the fertilizer solution tanks in hydroponic systems would be expected to rapidly propagate and spread throughout the system and potentially contaminate the entire crop.

Detection and characterization of Escherichia coli O157:H7 from feral pigeon in Qom province, Iran

Directory of Open Access Journals (Sweden)

Hossein Esameili

2015-02-01

Full Text Available Objective: To detect and characterize Escherichia coli (E. coli O157:H7 in feral pigeons in Qom province, Iran. Methods: In this survey, 290 cloacal samples were obtained from trapped feral pigeons in Qom province. Microbiological, biochemical and serological examinations were done to detect the E. coli O157:H7. Isolates were subjected to multiplex polymerase chain reaction for the detection of stx1, stx2, eaeA and hlyA genes. Results: Four samples (1.38% were positive for E. coli O157:H7 by using O157 and H7 antisera and only one E. coli O157:H7 strain isolated showed the presence of stx1, stx2, eaeA and hlyA genes. Conclusions: The results of present survey revealed that feral pigeons in Qom province had the potential to be a reservoir of E. coli O157:H7. The low prevalence of E. coli O157:H7 can be attributed to sampling each pigeon just once and fecal culture limits, and true prevalence of the E. coli O157:H7 might be higher than our findings.

Studies of binary cerium(IV)-praseodymium(IV) and cerium(IV)-terbium(IV) oxides as pigments for ceramic applications

International Nuclear Information System (INIS)

Furtado, L.M.L.

1991-01-01

It was investigated a series of pigments of general composition Ce 1-x Pr x O 2 , and Ce x Tb y O 2 , exhibiting radish and brown colors, respectively, and high temperature stability. The pigments were obtained by dissolving appropriate amounts of the pure lanthanide oxides in acids and precipitating the rare earths as mixed oxalates, which were isolated and calcined under air, at 1000 0 C. X-Ray powder diffractograms were consistent with a cubic structure for the pigments. Magnetic susceptibility measurements, using Gouy method, indicated the presence of Pr(IV) ions in the Ce 1-x Pr x O 2 pigments and of Terbium predominantly as Tb(III) ions in the Ce-tb mixed oxides. A new method, based on suspension of solid samples in PVA-STB gels (STB = sodium tetradecaborate), was employed for the measurements of the electronic spectra of the pigments. The thermal behaviour the pigments was investigated by the calcination of the oxalates in the temperature range of 500 to 1200 O C, from 10 to 60 minutes. (author)

Functional metagenomics of Escherichia coli O157:H7 interactions with spinach indigenous microorganisms during biofilm formation.

Directory of Open Access Journals (Sweden)

Michelle Q Carter

Full Text Available The increase in foodborne outbreaks worldwide attributed to fresh fruit and vegetables suggests that produce may serve as an ecological niche for enteric pathogens. Here we examined the interaction of E. coli O157:H7 (EcO157 with spinach leaf indigenous microorganisms during co-colonization and establishment of a mixed biofilm on a stainless steel surface. Stainless steel surface was selected to mimic the surface of produce-processing equipment, where retention of foodborne pathogens such as EcO157 could serve as a potential source for transmission. We observed a positive effect of spinach-associated microbes on the initial attachment of EcO157, but an antagonistic effect on the EcO157 population at the later stage of biofilm formation. Metagenomic analyses of the biofilm community with the GeoChip revealed an extremely diverse community (gene richness, 23409; Shannon-Weiner index H, 9.55. Presence of EcO157 in the mixed biofilm resulted in a significant decrease in the community α-diversity (t test, P<0.05, indicating a putative competition between the pathogen and indigenous spinach microbes. The decrease in the β-diversity of the EcO157-inoculated biofilm at 48 h (ANOVA, P<0.05 suggested a convergent shift in functional composition in response to EcO157 invasion. The success of EcO157 in the mixed biofilm is likely associated with its metabolic potential in utilizing spinach nutrients: the generation time of EcO157 in spinach lysates at 28°C is ~ 38 min, which is comparable to that in rich broth. The significant decrease in the abundance of many genes involved in carbon, nitrogen, and phosphorus cycling in the EcO157-inoculated biofilms (t test, P<0.05 further support our conclusion that competition for essential macronutrients is likely the primary interaction between the EcO157 and indigenous spinach-biofilm species.

Combination of CD157 and FLAER to Detect Peripheral Blood Eosinophils by Multiparameter Flow Cytometry.

Science.gov (United States)

Carulli, Giovanni; Marini, Alessandra; Sammuri, Paola; Domenichini, Cristiana; Ottaviano, Virginia; Pacini, Simone; Petrini, Mario

2015-01-01

The identification of eosinophils by flow cytometry is difficult because most of the surface antigens expressed by eosinophils are shared with neutrophils. Some methods have been proposed, generally based on differential light scatter properties, enhanced autofluorescence, lack of CD16 or selective positivity of CD52. Such methods, however, show several limitations. In the present study we report a novel method based on the analysis of glycosylphosphatidylinositol (GPI)-linked molecules. The combination of CD157 and FLAER was used, since FLAER recognizes all GPI-linked molecules, while CD157 is absent on the membrane of eosinophils and expressed by neutrophils. Peripheral blood samples from normal subjects and patients with variable percentages of eosinophils (n = 31), and without any evidence for circulating immature myeloid cells, were stained with the combination of FLAER-Alexa Fluor and CD157-PE. A FascCanto II cytometer was used. Granulocytes were gated after CD33 staining and eosinophils were identified as CD157(-)/FLAER(+) events. Neutrophils were identified as CD157(+)/FLAER(+) events. The percentages of eosinophils detected by this method showed a very significant correlation both with automated counting and with manual counting (r = 0.981 and 0.989, respectively). Sorting assays were carried out by a S3 Cell Sorter: cytospins obtained from CD157(-)/FLAER(+) events consisted of 100% eosinophils, while samples from CD157(+)/FLAER(+) events were represented only by neutrophils. In conclusion, this method shows high sensitivity and specificity in order to distinguish eosinophils from neutrophils by flow cytometry. However, since CD157 is gradually up-regulated throughout bone marrow myeloid maturation, our method cannot be applied to cases characterized by immature myeloid cells.

30 CFR 210.157 - What reports must I submit to suspend an MMS order under appeal?

Science.gov (United States)

2010-07-01

... accepts the following surety types: Form MMS-4435, Administrative Appeal Bond; Form MMS-4436, Letter of... order under appeal? 210.157 Section 210.157 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF..., and Geothermal Resources § 210.157 What reports must I submit to suspend an MMS order under appeal? (a...

Risk of Escherichia coli O157:H7 infection linked to the consumption of beef

Directory of Open Access Journals (Sweden)

Premarathne, J.M.K.J.K

2017-05-01

Full Text Available Escherichia coli O157:H7 is a major food-borne pathogen that has resulted in numerous outbreaks around the world. Widespread distribution of the organism in various ecological niches impedes the control measures. This study aimed to detect and quantify E. coli O157:H7 in beef sold in wet markets and hypermarkets in Malaysia and to determine the risk of E. coli O157:H7 infection linked to consumption of beef. The rfbO157 and flicH7 primers targeted on somatic antigen (O157 and flagellar antigen (H7 respectively of E. coli O157:H7 was used for the MPN-PCR method. A total of 99 beef samples were collected from local wet markets and hypermarkets. The highest E. coli O157:H7 contamination rate was observed in beef samples collected from wet markets (89.50%, whereas the contamination rate in hyper market A and B were compratively low (35.35 and 20% respectively. However, the microbial load was highest in the beef samples from hypermarket A (1100 MPN/g while E. coli O157:H7 bacterial load in beef samples from hypermarket B and wet market ranged from 3 to 93 MPN/g and 3 to 240 MPN/g, respectively. Using the Quantitative Microbial Risk Assessment (QMRA approach the risk was estimated incorporating the findings of the prevalence study and predictions based on home storage, cooking and consumption patterns. Three different exposure pathways were investigated to estimate the risk associated with contaminated beef and Monte Carlo simulation was used to determine the level of uncertainty. The developed model predicated that consumption of contaminated beef can be accountable for 1.83E+06 E. coli O157:H7 cases per year in Malaysia. The reliability of the model, data gaps and further research needs, is discussed. Through continuous improvement Quantitative Microbial Risk Assessment provides valuable insight into controlling and prevention strategies.

Sources of Escherichia coli O157 and experiences over the past 15 years in Sheffield, UK.

Science.gov (United States)

Chapman, P A

2000-01-01

In the first documented outbreak of HC caused by Escherichia coli O157, which occurred in the North-west USA in 1982, there was a strong association between infection and prior consumption of ground beef from a chain of fast food restaurants. Foods of bovine origin, including beef, milk and dairy products, have since been implicated in many outbreaks of infection world-wide. Investigations during the course of outbreaks, or at random, have shown that cattle are a major reservoir of E. coli O157. E. coli O157 was isolated from cattle at slaughter in Sheffield in 1987, this being the first isolation from cattle in the UK. Following a cluster of cases in May/June 1992, an abattoir study showed the organism to be present in 4% of cattle at slaughter and on up to a third of carcasses from rectal swab-positive animals. E. coli O157 was isolated from a food source (unpasteurized milk), for the first time in the UK, in Sheffield in May 1993. During surveillance in 1995-6, E. coli O157 was isolated from 15.7% of cattle, with a monthly prevalence which varied from 5 to 37%. E. coli O157 was also isolated from 2.2% of sheep. During surveillance in 1996, E. coli O157 was isolated from 5.9% of samples of lamb products and from 1.5% of samples of beef products, despite the prevalence in cattle being much higher than in sheep. Work is in progress to try to explain this higher prevalence in lamb products. During 1997 in Sheffield, the only cases of E. coli O157 for which a confirmed source was established were associated with direct animal contact on farm visits. During on-farm investigations of these cases, E. coli O157 was isolated from faecal samples from adult cattle, calves, three different breeds of sheep, two different breeds of pigs, goats and a pony.

Verocytotoxin producing E. Coli O157 on farms : prevalences, risk factors and transmission

NARCIS (Netherlands)

Schouten, J.M.

2005-01-01

Infection with verocytotoxin producing Escherichia coli (VTEC) O157 in humans can lead to mild or bloody diarrhoea, with e.g. the haemolytic uraemic syndrome (HUS) as possible complication. Cattle appear to be important reservoirs of O157 VTEC. The main

Study for the determination of samarium, europium,terbium, dysprosium and yttrium in gadolinium oxide matrix by means of atomic absorption spectrophotometry using a graphite furnace

International Nuclear Information System (INIS)

Caires, A.C.F.

1985-01-01

A study for determination of samarium, europium, terbium, dysprosium and yttrium in a gadolinium oxide matrix by atomic absorption spectrophotometry using a graphite furnace is presented. The best charrring and atomization conditions were estabilished for each element, the most convenient ressonance lines being selected as well. The study was carried out for the mentioned lanthanides both when pure and when in binary mixtures with gadolinium, besides those where all for them were together with gadolinium. The determination limits for pure lanthanides were found to be between 1.3 and 9.6 ng assuming a 20% relative standard deviation as acceptable. The detection limits were in the range 0.51 and 7.5 ng, assuming as positive any answer higher than twofold the standard deviation. (author) [pt

Sparkle/PM3 for the modeling of europium(III), gadolinium(III), and terbium(III) complexes

International Nuclear Information System (INIS)

Freire, Ricardo O.; Rocha, Gerd B.; Simas, Alfredo M.

2009-01-01

The Sparkle/PM3 model is extended to europium(III), gadolinium(III), and terbium(III) complexes. The validation procedure was carried out using only high quality crystallographic structures, for a total of ninety-six Eu(III) complexes, seventy Gd(III) complexes, and forty-two Tb(III) complexes. The Sparkle/PM3 unsigned mean error, for all interatomic distances between the trivalent lanthanide ion and the ligand atoms of the first sphere of coordination, is: 0.080 A for Eu(III); 0.063 A for Gd(III); and 0.070 A for Tb(III). These figures are similar to the Sparkle/AM1 ones of 0.082 A, 0.061 A, and 0.068 A respectively, indicating they are all comparable parameterizations. Moreover, their accuracy is similar to what can be obtained by present-day ab initio effective core potential full geometry optimization calculations on such lanthanide complexes. Finally, we report a preliminary attempt to show that Sparkle/PM3 geometry predictions are reliable. For one of the Eu(III) complexes, BAFZEO, we created hundreds of different input geometries by randomly varying the distances and angles of the ligands to the central Eu(III) ion, which were all subsequently fully optimized. A significant trend was unveiled, indicating that more accurate local minima geometries cluster at lower total energies, thus reinforcing the validity of sparkle model calculations. (author)

Characterization of biofilms produced by Escherichia coli O157 isolated from cattle hides

Science.gov (United States)

Milojević, L.; Velebit, B.; Baltić, T.; Nikolić, A.; Mitrović, R.; Đorđević, V.

2017-09-01

This study aimed to investigate possibility E. coli O157 from cattle hides to produced biofilms. We had 28 suspect primoisolates and 17 were confirmed to be E. coli O157. Biofilm production test showed that more than 50% of this isolates did not produce biofilm. From the other half of the isolates, 5 of them were weakly adherent, 3 were moderately adherent. Since E. coli O157 are one of the main foodborne hazards in meat processing industry and the discovery that some of them can produce moderately adherent biofilms, request necessity of strict implementation of HACCP procedures to prevent further expansion this pathogen.

Comparison of methods for the identification and sub-typing of O157 and non-O157 Escherichia coli serotypes and their integration into a polyphasic taxonomy approach

OpenAIRE

Prieto-Calvo M.A.; Omer M.K.; Alvseike O.; López M.; Alvarez-Ordóñez A.; Prieto M.

2016-01-01

Phenotypic, chemotaxonomic and genotypic data from 12 strains of Escherichia coli were collected, including carbon source utilisation profiles, ribotypes, sequencing data of the 16S–23S rRNA internal transcribed region (ITS) and Fourier transform-infrared (FT-IR) spectroscopic profiles. The objectives were to compare several identification systems for E. coli and to develop and test a polyphasic taxonomic approach using the four methodologies combined for the sub-typing of O157 and non-O157 E...

VUV and UV–vis optical study on KGd2F7 luminescent host doped with terbium and co-doped with europium

International Nuclear Information System (INIS)

Lisiecki, Radosław

2013-01-01

The KGd 2 F 7 :Tb and KGd 2 F 7 :Tb,Eu samples were obtained using a solid state reaction. Excitation spectra and emission spectra are reported and analyzed within the VUV–UV–vis spectral range. The intense green luminescence is observed in the KGd 2 F 7 :Tb while the combined emission of terbium and europium in the KGd 2 F 7 :Tb,Eu covers substantially the region of white light. The materials under study can be effectively excited making use of intense f–d transitions of Tb 3+ in the VUV–UV region. Experimental lifetimes of luminescent levels have been measured and discussed. It was found that the considerable energy transfer from Tb 3+ to Eu 3+ occurs. -- Highlights: • The prospective green and white emitting phosphors. • The effective VUV and UV–vis excitation process. • The considerable energy transfer among optically active ions. • The influence of (Tb, Eu) co-doping on relaxation dynamic of excited states

Functional Metagenomics of Escherichia coli O157:H7 Interactions with Spinach Indigenous Microorganisms during Biofilm Formation

Science.gov (United States)

Carter, Michelle Q.; Xue, Kai; Brandl, Maria T.; Liu, Feifei; Wu, Liyou; Louie, Jacqueline W.; Mandrell, Robert E.; Zhou, Jizhong

2012-01-01

The increase in foodborne outbreaks worldwide attributed to fresh fruit and vegetables suggests that produce may serve as an ecological niche for enteric pathogens. Here we examined the interaction of E. coli O157:H7 (EcO157) with spinach leaf indigenous microorganisms during co-colonization and establishment of a mixed biofilm on a stainless steel surface. Stainless steel surface was selected to mimic the surface of produce-processing equipment, where retention of foodborne pathogens such as EcO157 could serve as a potential source for transmission. We observed a positive effect of spinach-associated microbes on the initial attachment of EcO157, but an antagonistic effect on the EcO157 population at the later stage of biofilm formation. Metagenomic analyses of the biofilm community with the GeoChip revealed an extremely diverse community (gene richness, 23409; Shannon-Weiner index H, 9.55). Presence of EcO157 in the mixed biofilm resulted in a significant decrease in the community α-diversity (t test, Pbiofilm at 48 h (ANOVA, Pbiofilm is likely associated with its metabolic potential in utilizing spinach nutrients: the generation time of EcO157 in spinach lysates at 28°C is ∼ 38 min, which is comparable to that in rich broth. The significant decrease in the abundance of many genes involved in carbon, nitrogen, and phosphorus cycling in the EcO157-inoculated biofilms (t test, Pbiofilm species. PMID:22957052

Antibacterial effect of lactoferricin B on Escherichia coli O157:H7 in ground beef.

Science.gov (United States)

Venkitanarayanan, K S; Zhao, T; Doyle, M P

1999-07-01

The antibacterial activity of lactoferricin B on enterohemorrhagic Escherichia coli O157:H7 in 1% peptone medium and ground beef was studied at 4 and 10 degrees C. In 1% peptone medium, 50 and 100 microg of lactoferricin B per ml reduced E. coli O157:H7 populations by approximately 0.7 and 2.0 log CFU/ml, respectively. Studies comparing the antibacterial effect of lactoferricin B on E. coli O157:H7 in 1% peptone at pH 5.5 and 7.2 did not reveal any significant difference (P > 0.5) at the two pH values. Lactoferricin B (100 microg/g) reduced E. coli O157:H7 population in ground beef by about 0.8 log CFU/g (P 0.5) was observed in the total plate count between treatment and control ground beef samples stored at 4 and 10 degrees C. The antibacterial effect of lactoferricin B on E. coli O157:H7 observed in this study is not of sufficient magnitude to merit its use in ground beef for controlling the pathogen.

Structural, elastic, mechanical and thermodynamic properties of Terbium oxide: First-principles investigations

Directory of Open Access Journals (Sweden)

Samah Al-Qaisi

Full Text Available First-principles investigations of the Terbium oxide TbO are performed on structural, elastic, mechanical and thermodynamic properties. The investigations are accomplished by employing full potential augmented plane wave FP-LAPW method framed within density functional theory DFT as implemented in the WIEN2k package. The exchange-correlation energy functional, a part of the total energy functional, is treated through Perdew Burke Ernzerhof scheme of the Generalized Gradient Approximation PBEGGA. The calculations of the ground state structural parameters, like lattice constants a0, bulk moduli B and their pressure derivative B′ values, are done for the rock-salt RS, zinc-blende ZB, cesium chloride CsCl, wurtzite WZ and nickel arsenide NiAs polymorphs of the TbO compound. The elastic constants (C11, C12, C13, C33, and C44 and mechanical properties (Young’s modulus Y, Shear modulus S, Poisson’s ratio σ, Anisotropic ratio A and compressibility β, were also calculated to comprehend its potential for valuable applications. From our calculations, the RS phase of TbO compound was found strongest one mechanically amongst the studied cubic structures whereas from hexagonal phases, the NiAs type structure was found stronger than WZ phase of the TbO. To analyze the ductility of the different structures of the TbO, Pugh’s rule (B/SH and Cauchy pressure (C12–C44 approaches are used. It was found that ZB, CsCl and WZ type structures of the TbO were of ductile nature with the obvious dominance of the ionic bonding while RS and NiAs structures exhibited brittle nature with the covalent bonding dominance. Moreover, Debye temperature was calculated for both cubic and hexagonal structures of TbO in question by averaging the computed sound velocities. Keywords: DFT, TbO, Elastic properties, Thermodynamic properties

Reducing of escherichia coli O 157 serotype and cohabitant flora by irradiation in minced meat

International Nuclear Information System (INIS)

Halkman, A.K.; Dogan, H.B.; Yazici, N.

2001-01-01

Escherichia coli O157:H7 was conclusively identified as a pathogen in 1982 following its association with two food-related outbreaks of an unusual gastrointestinal illness. The infectious dose of E. coli O157 is very low, and as a result the organism can be transmitted efficiently not only via contaminated foods but also person to person (Doyle 1991, Karch et al. 1996). Although not definitely linked, consumption of undercooked meats and mainly hamburgers has been strongly implicated in hemorrhagic uremic colitis and hemolytic uremic syndrome. Water and unpasteurized milk are also recognized as sources of outbreaks (Yu and Bruno 1996 , Venkateswaran et al. 1997). Meat and milk products are the most important foods for E. coli O157:H7 outbreaks. Apple cider, drinking and swimming waters are also important for outbreaks. Literature reveals that E. coli O157:H7 is not resistant to the application of radiations. Gamma rays obtained from ''6''0Co ve ''1''3''7Gs sources find wide application in the food protection as these rays eliminate various pathogen including E.coli O157:H7 in the solid foods. Irradiation of food is less effective at temperature below freezing point. In USA beef is allowed to prevent E.coli O157:H7 infection (Farkas et al.1998;Fujikawa et al.1992; Harewood et al.1994;Park et al.1999)

Selection of antibiotics in detection procedure of Escherichia coli O157:H7 in vegetables

Science.gov (United States)

Hoang, Hoang A.; Nhung, Nguyen T. T.

2017-09-01

Detection of Escherichia coli O157:H7 in ready-to-eat fresh vegetables is important since this bacteria is considered as one of the most important pathogens in relation to public health. However, it could be a big challenge for detection of initial low concentrations of E. coli O157:H7 in the samples. In this study, selection of antibiotics that suppress growth of background bacteria to enable detection of E. coli O157:H7 in ready-to-eat fresh vegetables was investigated. Firstly, different combinations of two antibiotics, i.e. novobiocin (N) and vancomycin (V), in BHI broth were conducted. The three antibiotic combinations were preliminary examined their effect on the growth of E. coli O157:H7 and Bacillus spp. in broth based on OD600nm measurement. The combination of both the antibiotics was selected to examine their possibility to support detection of E. coli O157:H7 in vegetables. It was successful when two antibiotics showed their support in detection of E. coli O157:H7 at very low concentration of 2 CFU per one gram of lettuce. Usage of these antibiotics is simple and cheap in the detection procedure and could be applied to other types of ready-to-eat fresh vegetables popular in Vietnam.

78 FR 54168 - Special Local Regulation, Cumberland River, Mile 157.0 to 159.0; Ashland City, TN

Science.gov (United States)

2013-09-03

... Local Regulation, Cumberland River, Mile 157.0 to 159.0; Ashland City, TN AGENCY: Coast Guard, DHS... Special local regulation; Cumberland River, Miles 157.0 to 159.0, Ashland City, TN. (a) Location. The... regulation for the waters of the Cumberland River beginning at mile marker 157.0 and ending at mile marker...

Cloacael Carriage and Multidrug Resistance Escherichia coli O157:H7 from Poultry Farms, Eastern Ethiopia.

Science.gov (United States)

Shecho, Mude; Thomas, Naod; Kemal, Jelalu; Muktar, Yimer

2017-01-01

A cross-sectional study was carried out to determine antimicrobial drug resistance patterns of E. coli O157:H7 isolates and estimate the level of the pathogen. A total of 194 cloacae swab samples were collected randomly in two poultry farms. Standard cultural, biochemical, and serological (latex agglutination) methods were used to isolate E. coli O157:H7. The isolates were subjected to antimicrobial susceptibility testing using disc diffusion method. Out of 194 cloacae samples examined, 13.4% ( n = 26) were found to be positive for E. coli O157:H7. The finding indicated differences in E. coli O157:H7 infection among the different risk factors. Chicken from Adele Poultry Farm showed higher E. coli O157:H7 infection (OR = 3.89) than Haramaya University poultry farm and young birds had more infection (OR = 4.62) than adult birds. Of the total 14 antimicrobials included in the panel of study, the susceptibility results were varied with 96.15% and 0% E. coli O157:H7 isolates expressing resistance to erythromycin, clindamycin, spectinomycin, and ciprofloxacin, respectively. Multidrug resistance to more than two antimicrobial agents was detected in 24 (92.30%) of the isolates. The study showed high presence of antimicrobial resistant isolates of E. coli O157:H7. Further study is required to better understand the ecology and evolution of bacterial resistance to antimicrobial agents.

Cloacael Carriage and Multidrug Resistance Escherichia coli O157:H7 from Poultry Farms, Eastern Ethiopia

Directory of Open Access Journals (Sweden)

Mude Shecho

2017-01-01

Full Text Available A cross-sectional study was carried out to determine antimicrobial drug resistance patterns of E. coli O157:H7 isolates and estimate the level of the pathogen. A total of 194 cloacae swab samples were collected randomly in two poultry farms. Standard cultural, biochemical, and serological (latex agglutination methods were used to isolate E. coli O157:H7. The isolates were subjected to antimicrobial susceptibility testing using disc diffusion method. Out of 194 cloacae samples examined, 13.4% (n=26 were found to be positive for E. coli O157:H7. The finding indicated differences in E. coli O157:H7 infection among the different risk factors. Chicken from Adele Poultry Farm showed higher E. coli O157:H7 infection (OR = 3.89 than Haramaya University poultry farm and young birds had more infection (OR = 4.62 than adult birds. Of the total 14 antimicrobials included in the panel of study, the susceptibility results were varied with 96.15% and 0% E. coli O157:H7 isolates expressing resistance to erythromycin, clindamycin, spectinomycin, and ciprofloxacin, respectively. Multidrug resistance to more than two antimicrobial agents was detected in 24 (92.30% of the isolates. The study showed high presence of antimicrobial resistant isolates of E. coli O157:H7. Further study is required to better understand the ecology and evolution of bacterial resistance to antimicrobial agents.

Molecular Characterization of Human Atypical Sorbitol-Fermenting Enteropathogenic Escherichia coli O157 Reveals High Diversity.

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Kossow, Annelene; Zhang, Wenlan; Bielaszewska, Martina; Rhode, Sophie; Hansen, Kevin; Fruth, Angelika; Rüter, Christian; Karch, Helge; Mellmann, Alexander

2016-05-01

Alongside the well-characterized enterohemorrhagic Escherichia coli (EHEC) O157:H7, serogroup O157 comprises sorbitol-fermenting typical and atypical enteropathogenic E. coli (EPEC/aEPEC) strains that carry the intimin-encoding gene eae but not Shiga toxin-encoding genes (stx). Since little is known about these pathogens, we characterized 30 clinical isolates from patients with hemolytic uremic syndrome (HUS) or uncomplicated diarrhea with respect to their flagellin gene (fliC) type and multilocus sequence type (MLST). Moreover, we applied whole-genome sequencing (WGS) to determine the phylogenetic relationship with other eae-positive EHEC serotypes and the composition of the rfbO157 region. fliC typing resulted in five fliC types (H7, H16, H34, H39, and H45). Isolates of each fliC type shared a unique ST. In comparison to the 42 HUS-associated E. coli (HUSEC) strains, only the stx-negative isolates with fliCH7 shared their ST with EHEC O157:H7/H(-) strains. With the exception of one O157:H(-) fliCH16 isolate, HUS was exclusively associated with fliCH7. WGS corroborated the separation of the fliCH7 isolates, which were closely related to the EHEC O157:H7/H(-) isolates, and the diverse group of isolates exhibiting different fliC types, indicating independent evolution of the different serotypes. This was also supported by the heterogeneity within the rfbO157 region that exhibited extensive recombinations. The genotypic subtypes and distribution of clinical symptoms suggested that the stx-negative O157 strains with fliCH7 were originally EHEC strains that lost stx The remaining isolates form a distinct and diverse group of atypical EPEC isolates that do not possess the full spectrum of virulence genes, underlining the importance of identifying the H antigen for clinical risk assessment. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Inhibition of Escherichia coli O157:H7 on stainless steel using Pseudomonas veronii biofilms.

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Kim, Y; Kim, H; Beuchat, L R; Ryu, J-H

2018-05-01

We produced a Pseudomonas veronii biofilm on the surface of a stainless steel that is inhibitory to Escherichia coli O157:H7. Pseudomonas veronii strain KACC 81051BP, isolated from lettuce, readily formed biofilm on the surface of stainless steel coupons (SSCs) immersed in tryptic soy broth at 25°C. Cells showed significantly (P ≤ 0·05) enhanced tolerance to desiccation stress (43% relative humidity (RH)) and retained antimicrobial activity against E. coli O157:H7. The number of E. coli O157:H7 (control; 4·1 ± 0·1 log CFU per coupon) on sterile SSCs decreased to 2·7 ± 0·2 log CFU per coupon after exposure to 43% RH at 25°C for 48 h, while the population of E. coli O157:H7 (4·1 ± 0·0 log CFU per coupon) on SSCs containing P. veronii biofilm decreased to below the theoretical detection limit (1·5 log CFU per coupon) within 24 h. The antimicrobial biofilm produced on stainless steel may have application in preventing cross-contamination by E. coli O157:H7 on other abiotic surfaces in food-contact environments. The presence of Escherichia coli O157:H7 on environmental surfaces of food manufacturing, transportation and storage facilities is a significant food safety concern because it can result in cross-contamination of food products. In this study, we developed a Pseudomonas veronii biofilm on the surface of a stainless steel that inhibits the growth of E. coli O157:H7. Since P. veronii in biofilm resists desiccation, it provides persistent antimicrobial activity. Information presented here provides novel and practical insights to developing biological strategies to inactivate E. coli O157:H7 on diverse surfaces in food processing and handling environments. © 2018 The Society for Applied Microbiology.

Comparison of the fate of the top six non-O157 shiga-toxin producing Escherichia coli (STEC) and E. coli O157:H7 during the manufacture of dry fermented sausages.

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Balamurugan, S; Ahmed, Rafath; Gao, Anli; Strange, Phil

2017-10-16

The study examined the relative fate of the top six non-O157 shiga-toxin producing Escherichia coli (STEC) and E. coli O157:H7 during the manufacture of dry fermented sausages (DFS). Three separate batches of sausages containing a five-strain cocktail for each serogroup and uninoculated control were manufactured and subjected to identical fermentation, maturation and dry curing conditions. Changes in physicochemical properties and inoculated STEC numbers were enumerated during the DFS production stages and log reduction and log reduction rates were calculated. Inoculation of very high concentrations (8logCFUg -1 ) of STEC in the sausage batter did not significantly (P>0.05) affect the changes in the pH, a w , moisture, protein, fat content compared to the uninoculated DFS. There was a significant (P0.05) from each other. These results indicate that the lethality of DFS production processes observed against E. coli O157:H7 would result in a similar inactivation of the top six non-O157 STEC. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Earthworms as vectors of Escherichia coli O157:H7 in soil and vermicomposts.

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Williams, A Prysor; Roberts, Paula; Avery, Lisa M; Killham, Ken; Jones, David L

2006-10-01

Survival and movement of Escherichia coli O157:H7 in both soil and vermicompost is of concern with regards to human health. Whilst it is accepted that E. coli O157:H7 can persist for considerable periods in soils, it is not expected to survive thermophilic composting processes. However, the natural behavior of earthworms is increasingly utilized for composting (vermicomposting), and the extent to which earthworms promote the survival and dispersal of the bacterium within such systems is unknown. The faecal material produced by earthworms provides a ready supply of labile organic substrates to surrounding microbes within soil and compost, thus promoting microbial activity. Earthworms can also cause significant movement of organisms through the channels they form. Survival and dispersal of E. coli O157:H7 were monitored in contaminated soil and farmyard manure subjected to earthworm digestion over 21 days. Our findings lead to the conclusion that anecic earthworms such as Lumbricus terrestris may significantly aid vertical movement of E. coli O157 in soil, whereas epigeic earthworms such as Dendrobaena veneta significantly aid lateral movement within compost. Although the presence of earthworms in soil and compost may aid proliferation of E. coli O157 in early stages of contamination, long-term persistence of the pathogen appears to be unaffected.

Protease-Activated Receptor 4 Variant p.Tyr157Cys Reduces Platelet Functional Responses and Alters Receptor Trafficking.

Science.gov (United States)

Norman, Jane E; Cunningham, Margaret R; Jones, Matthew L; Walker, Mary E; Westbury, Sarah K; Sessions, Richard B; Mundell, Stuart J; Mumford, Andrew D

2016-05-01

Protease-activated receptor 4 (PAR4) is a key regulator of platelet reactivity and is encoded by F2RL3, which has abundant rare missense variants. We aimed to provide proof of principle that rare F2LR3 variants potentially affect platelet reactivity and responsiveness to PAR1 antagonist drugs and to explore underlying molecular mechanisms. We identified 6 rare F2RL3 missense variants in 236 cardiac patients, of which the variant causing a tyrosine 157 to cysteine substitution (Y157C) was predicted computationally to have the greatest effect on PAR4 structure. Y157C platelets from 3 cases showed reduced responses to PAR4-activating peptide and to α-thrombin compared with controls, but no reduction in responses to PAR1-activating peptide. Pretreatment with the PAR1 antagonist vorapaxar caused lower residual α-thrombin responses in Y157C platelets than in controls, indicating greater platelet inhibition. HEK293 cells transfected with a PAR4 Y157C expression construct had reduced PAR4 functional responses, unchanged total PAR4 expression but reduced surface expression. PAR4 Y157C was partially retained in the endoplasmic reticulum and displayed an expression pattern consistent with defective N-glycosylation. Mutagenesis of Y322, which is the putative hydrogen bond partner of Y157, also reduced PAR4 surface expression in HEK293 cells. Reduced PAR4 responses associated with Y157C result from aberrant anterograde surface receptor trafficking, in part, because of disrupted intramolecular hydrogen bonding. Characterization of PAR4 Y157C establishes that rare F2RL3 variants have the potential to markedly alter platelet PAR4 reactivity particularly after exposure to therapeutic PAR1 antagonists. © 2016 American Heart Association, Inc.

75 FR 10460 - Improving Tracing Procedures for E. coli O157:H7 Positive Raw Beef Product

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2010-03-08

... Tracing Procedures for E. coli O157:H7 Positive Raw Beef Product AGENCY: Food Safety and Inspection... has found positive for Escherichia coli (E. coli) O157:H7. FSIS will also discuss additional verification activities the Agency will conduct at suppliers in response to positive E. coli O157:H7 results...

Plant lesions promote the rapid multiplication of Escherichia coli O157:H7 on post-harvest lettuce

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Several outbreaks of Escherichia coli O157:H7 (EcO157) infections have been associated with minimally processed leafy vegetables in the U.S. Harvesting and processing cause plant tissue damage. In order to assess the role of plant tissue damage in the contamination of leafy greens with EcO157, the e...

10 CFR 52.157 - Contents of applications; technical information in final safety analysis report.

Science.gov (United States)

2010-01-01

...; technical information in final safety analysis report. The application must contain a final safety analysis... 10 Energy 2 2010-01-01 2010-01-01 false Contents of applications; technical information in final safety analysis report. 52.157 Section 52.157 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) LICENSES...

Fate of Escherichia coli O157: H7 in agricultural soils amended with different organic fertilizers.

Science.gov (United States)

Yao, Zhiyuan; Yang, Li; Wang, Haizhen; Wu, Jianjun; Xu, Jianming

2015-10-15

Five organic fertilizers (vermicompost, pig manure, chicken manure, peat and oil residue) were applied to agricultural soils to study their effects on the survival of Escherichia coli O157:H7 (E. coli O157:H7). Results showed that E. coli O157:H7 survival changed greatly after organic fertilizers application, with shorter td values (survival time needed to reach the detection limit of 100 CFU g(-1)) (12.57±6.57 days) in soils amended with chicken manure and the longest (25.65±7.12 days) in soils amended with pig manure. Soil pH, EC and free Fe/Al (hydro) oxides were significant explanatory factors for E. coli O157:H7 survival in the original soils. Soil constituents (minerals and organic matter) and changes in their surface charges with pH increased the effect of soil pH on E. coli O157:H7 survival. However, electrical conductivity played a more important role in regulating E. coli O157:H7 survival in fertilizer-amended soils. This study highlighted the importance of choosing appropriate organic fertilizers in the preharvest environment to reduce food-borne bacterial contamination. Copyright © 2015 Elsevier B.V. All rights reserved.

Prevalence and Genomic Characterization of Escherichia coli O157:H7 in Cow-Calf Herds throughout California.

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Worley, Jay N; Flores, Kristopher A; Yang, Xun; Chase, Jennifer A; Cao, Guojie; Tang, Shuai; Meng, Jianghong; Atwill, Edward R

2017-08-15

Escherichia coli serotype O157:H7 is a zoonotic food- and waterborne bacterial pathogen that causes a high hospitalization rate and can cause life-threatening complications. Increasingly, E. coli O157:H7 infections appear to originate from fresh produce. Ruminants, such as cattle, are a prominent reservoir of E. coli O157:H7 in the United States. California is one of the most agriculturally productive regions in the world for fresh produce, beef, and milk. The close proximity of fresh produce and cattle presents food safety challenges on a uniquely large scale. We performed a survey of E. coli O157:H7 on 20 farms in California to observe the regional diversity and prevalence of E. coli O157:H7. Isolates were obtained from enrichment cultures of cow feces. Some farms were sampled on two dates. Genomes from isolates were sequenced to determine their relatedness and pathogenic potential. E. coli O157:H7 was isolated from approximately half of the farms. The point prevalence of E. coli O157:H7 on farms was highly variable, ranging from zero to nearly 90%. Within farms, generally one or a few lineages were found, even when the rate of isolation was high. On farms with high isolation rates, a single clonal lineage accounted for most of the isolates. Farms that were visited months after the first visit might have had the same lineages of E. coli O157:H7. Strains of E. coli O157:H7 may be persistent for months on farms. IMPORTANCE This survey of 20 cow-calf operations from different regions of California provides an in depth look at resident Escherichia coli O157:H7 populations at the molecular level. E. coli O157:H7 is found to have a highly variable prevalence, and with whole-genome sequencing, high prevalences in herds were found to be due to a single lineage shed from multiple cows. Few repeat lineages were found between farms in this area; therefore, we predict that E. coli O157:H7 has significant diversity in this area beyond what is detected in this survey. All

Survival of Escherichia coli O157:H7 in needle-tenderized dry cured Westphalian ham.

Science.gov (United States)

Graumann, Gary H; Holley, Richard A

2007-09-15

Westphalian ham is a dry cured, ready-to-eat product that is manufactured without a lethal heat treatment. Hams are preserved by a process that involves curing, fermenting, smoking and drying, which may take 3 months or more to complete. The process can be accelerated by tenderizing the meat with solid needles, to increase the rate of cure-salt diffusion throughout muscle tissues. In this study, intact hams were immersed in a solution containing a five strain cocktail of Escherichia coli O157:H7 at 8 log cfu/mL, to determine whether needle treatment before cure application would internalize organisms from the surface. In two trials, the survival of E. coli O157:H7 on external surfaces and within deep tissues after needle treatment was followed during the ripening of hams. The injured E. coli O157:H7 cells were recovered by plating samples on pre-poured Tryptic Soy Agar plates which were incubated for 3 to 4 h at 35 degrees C, overlaid with Sorbitol MacConkey Agar containing cefixime and tellurite and re-incubated at 35 degrees C for 48 to 72 h. Inoculated-injected hams initially carried E. coli O157:H7 at numbers of 7.3 and 4.6 log cfu/g E. coli O157:H7 on the surface and inside, respectively. After 112 d of ripening, which included 79 d of drying, no E. coli O157:H7 were detected at the surface of hams following enrichment, whereas in deep tissue the organism was recovered at numbers of 3.1 log cfu/g. The Westphalian ham ripening procedure evidently was not adequate to eliminate E. coli O157:H7 internalized by needle tenderization.

Spread and change in stress resistance of Shiga toxin-producing Escherichia coli O157 on fungal colonies.

Science.gov (United States)

Lee, Ken-Ichi; Kobayashi, Naoki; Watanabe, Maiko; Sugita-Konishi, Yoshiko; Tsubone, Hirokazu; Kumagai, Susumu; Hara-Kudo, Yukiko

2014-11-01

To elucidate the effect of fungal hyphae on the behaviour of Shiga toxin-producing Escherichia coli (STEC) O157, the spread and change in stress resistance of the bacterium were evaluated after coculture with 11 species of food-related fungi including fermentation starters. Spread distances of STEC O157 varied depending on the co-cultured fungal species, and the motile bacterial strain spread for longer distances than the non-motile strain. The population of STEC O157 increased when co-cultured on colonies of nine fungal species but decreased on colonies of Emericella nidulans and Aspergillus ochraceus. Confocal scanning microscopy visualization of green fluorescent protein-tagged STEC O157 on fungal hyphae revealed that the bacterium colonized in the water film that existed on and between hyphae. To investigate the physiological changes in STEC O157 caused by co-culturing with fungi, the bacterium was harvested after 7 days of co-culturing and tested for acid resistance. After co-culture with eight fungal species, STEC O157 showed greater acid resistance compared to those cultured without fungi. Our results indicate that fungal hyphae can spread the contamination of STEC O157 and can also enhance the stress resistance of the bacteria. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

A new luminescent terbium 4-methylsalicylate complex as a novel sensor for detecting the purity of methanol.

Science.gov (United States)

Zeng, Cheng-Hui; Yang, Yang-Yi; Zhu, Yi-Min; Wang, Hong-Ming; Chu, Tian-Shu; Ng, Seik Weng

2012-01-01

A new dinuclear terbium complex [Tb(2)(4-msal)(6)(H(2)O)(4)]·6H(2)O (1) (4-msal = 4-methylsalcylate) was synthesized. Its structure was determined by single crystal X-ray diffraction, and the complex was characterized by PXRD, FT-IR, fluorescence, TGA and DTA. Complex 1 exists as discrete molecules that are linked by extensive O-H … O hydrogen bonds into a 3D network. The luminescence lifetimes of 3 μM methanol solution and solid sample of 1 are 1.321 and 1.009 ms, respectively. The quantum yield of solid sample is 6.0%. The luminescence quenched more than 50% when 3% (vol/vol) different impurities (acetone, acetonitrile, chloroform, dichloromethane, dioxane, DMF, DMSO, ethanol, ether, ethyl acetate, glycol, H(2)O, hexane, TEA, THF and toluene or their mixture) were added. The inverse linear relationship between the Lg value of fluorescence intensity and the volume ratio of the minor component (to a maximum of 20%) is interpreted in terms of LgI = a-bX (I: luminescence intensity; X: volume ratio of impurities in methanol; a, b are constants). So 1 is a potential luminescent sensor for analyzing the purity of methanol. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

Acid and alcohol tolerance of Escherichia coli O157:H7 in pulque, a typical Mexican beverage.

Science.gov (United States)

Gómez-Aldapa, Carlos A; Díaz-Cruz, Claudio A; Villarruel-López, Angelica; Del Refugio Torres-Vitela, M; Rangel-Vargas, Esmeralda; Castro-Rosas, Javier

2012-03-01

Pulque is a traditional Mexican fermented alcoholic beverage produced from the nectar of maguey agave plants. No data exist on the behavior of Escherichia coli O157:H7 in agave nectar and pulque. An initial trial was done of the behavior of E. coli O157:H7 during fermentation of nectar from a single producer, a nectar mixture from different producers and "seed" pulque. A second trial simulating artisanal pulque production was done by contaminating fresh nectar with a cocktail of three E. coli O157:H7 strains, storing at 16 ° and 22 °C for 14 h, adding seed pulque and fermenting until pulque was formed. A third trial used pulque from the second trial stored at 22 °C as seed to ferment fresh nectar at 22 °C for 48 h (fermentation cycle). This procedure was repeated for an additional two fermentation cycles. During incubation at 16 ° or 22 °C in the first trial, the E. coli O157:H7 strains multiplied in both the single producer nectar and nectar mixture, reaching maximum concentration at 12h. E. coli O157:H7 cell concentration then decreased slowly, although it survived at least 72 h in both fermented nectars. E. coli O157:H7 did not multiply in the seed pulque but did survive at least 72 h. In the second trial, the numbers of E. coli O157:H7 increased approximately 1.5 log CFU/ml at 22 °C and 1.2 log CFU/ml at 16 °C after 14 h. After seed pulque was added, E. coli O157:H7 concentration decreased to approximately 2 log CFU/ml, and then remained constant until pulque was produced. In the third trial, the E. coli O157:H7 cells multiplied and survived during at least three nectar fermentation cycles. The results suggest that E. coli O157:H7 can develop acid and alcohol tolerance in pulque, and constitutes a public health risk for pulque consumers. Copyright © 2011 Elsevier B.V. All rights reserved.

18 CFR 157.9 - Notice of application and notice of schedule for environmental review.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Notice of application and notice of schedule for environmental review. 157.9 Section 157.9 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER NATURAL GAS ACT APPLICATIONS FOR CERTIFICATES OF PUBLIC...

Effect of Neem (Azadirachta indica on the Survival of Escherichia coli O157:H7 in Dairy Manure

Directory of Open Access Journals (Sweden)

Subbarao V. Ravva

2015-07-01

Full Text Available Escherichia coli O157:H7 (EcO157 shed in cattle manure can survive for extended periods of time and intervention strategies to control this pathogen at the source are critical as produce crops are often grown in proximity to animal raising operations. This study evaluated whether neem (Azadirachta indica, known for its antimicrobial and insecticidal properties, can be used to amend manure to control EcO157. The influence of neem materials (leaf, bark, and oil on the survival of an apple juice outbreak strain of EcO157 in dairy manure was monitored. Neem leaf and bark supplements eliminated the pathogen in less than 10 d with a D-value (days for 90% elimination of 1.3 d. In contrast, nearly 4 log CFU EcO157/g remained after 10 d in neem-free manure control. The ethyl acetate extractable fraction of neem leaves was inhibitory to the growth of EcO157 in LB broth. Azadirachtin, a neem product with insect antifeedant properties, failed to inhibit EcO157. Application of inexpensive neem supplements to control pathogens in manure and possibly in produce fields may be an option for controlling the transfer of foodborne pathogens from farm to fork.

Subtractive Inhibition Assay for the Detection of E. coli O157:H7 Using Surface Plasmon Resonance

Directory of Open Access Journals (Sweden)

Chengyan Si

2011-03-01

Full Text Available A surface plasmon resonance (SPR immunosensor was developed for the detection of E. coli O157:H7 by means of a new subtractive inhibition assay. In the subtractive inhibition assay, E. coli O157:H7 cells and goat polyclonal antibodies for E. coli O157:H7 were incubated for a short of time, and then the E. coli O157:H7 cells which bound antibodies were removed by a stepwise centrifugation process. The remaining free unbound antibodies were detected through interaction with rabbit anti-goat IgG polyclonal antibodies immobilized on the sensor chip using a BIAcore 3000 biosensor. The results showed that the signal was inversely correlated with the concentration of E. coli O157:H7 cells in a range from 3.0 × 104 to 3.0 × 108 cfu/mL with a detection limit of 3.0 × 104 cfu/mL. Compared with direct SPR by immobilizing antibodies on the chip surface to capture the bacterial cells and ELISA for E. coli O157:H7 (detection limit: both 3.0 × 105 cfu/mL in this paper, the detection limit of subtractive inhibition assay method was reduced by one order of magnitude. The method simplifies bacterial cell detection to protein-protein interaction, which has the potential for providing a practical alternative for the monitoring of E. coli O157:H7 and other pathogens.

Survival of Escherichia coli O157:H7 in ground beef jerky assessed on two plating media.

Science.gov (United States)

Harrison, J A; Harrison, M A; Rose, R A

1998-01-01

Recent outbreaks of food-borne illness due to Salmonella spp. in beef jerky and Escherichia coli O157:H7 in venison jerky, coupled with the fact that a variety of preparation methods and dying procedures abound, raise concern over the safety of processed meat products made in the home. The potential of injured bacterial cells to regain the ability to cause illness is a particular threat with pathogens such as E. coli O157:H7, which is believed to have a low infectious dose. This study examined the efficacy of various methods of jerky preparation in reducing populations of E, coli O157:H7 in ground beef jerky and compared the recovery rate of E. coli O157:H7 on two selective plating media, modified sorbitol MacConkey agar (MSMA) and modified eosin methylene blue agar (MEMB). Populations of E. coli O157:H7 in both heated and unheated samples exhibited a greater decline during drying when a nitrite and salt cure mix was added during jerky preparation. When recovery of E. coli O157:H7 on MSMA and MEMB was compared, a trend toward slightly higher recovery rates with MEMB was observed. On the basis of these results, MEMB is a suitable alternative to MSMA for the recovery of E. coli O157:H7 from heated and dried meat samples similar to beef jerky.

The antimicrobial peptide cathelicidin protects mice from Escherichia coli O157:H7-mediated disease.

Directory of Open Access Journals (Sweden)

Milan Chromek

Full Text Available This study investigated the role of the antimicrobial peptide cathelicidin in Escherichia coli O157:H7 infection and subsequent renal damage. Mouse and human cathelicidin, CRAMP and LL-37, respectively, killed E. coli O157:H7 in vitro. Intestines from healthy wild-type (129/SvJ and cathelicidin-knock-out (Camp(-/- mice were investigated, showing that cathelicidin-deficient mice had a thinner colonic mucus layer compared with wild-type mice. Wild-type (n = 11 and cathelicidin-knock-out (n = 11 mice were inoculated with E. coli O157:H7. Cathelicidin-deficient animals exhibited higher fecal counts of E. coli O157:H7 and bacteria penetrated the mucus forming attaching-and-effacing lesions to a much higher extent than in wild-type animals. Cathelicidin knock-out mice developed symptoms (9/11 as well as anemia, thrombocytopenia and extensive renal tubular damage while all cathelicidin-producing mice remained asymptomatic with normal laboratory findings. When injected with Shiga toxin intraperitoneally, both murine strains developed the same degree of renal tubular damage and clinical disease indicating that differences in sensitivity to infection between the murine strains were related to the initial intestinal response. In conclusion, cathelicidin substantially influenced the antimicrobial barrier in the mouse colon mucosa. Cathelicidin deficiency lead to increased susceptibility to E. coli O157:H7 infection and subsequent renal damage. Administration of cathelicidin or stimulation of endogenous production may prove to be novel treatments for E. coli O157:H7-induced hemolytic uremic syndrome.

Reversible Inhibitors of Monoamine Oxidase-A (RIMAs): Robust, Reversible Inhibition of Human Brain MAO-A by CX157

Science.gov (United States)

Fowler, Joanna S; Logan, Jean; Azzaro, Albert J; Fielding, Robert M; Zhu, Wei; Poshusta, Amy K; Burch, Daniel; Brand, Barry; Free, James; Asgharnejad, Mahnaz; Wang, Gene-Jack; Telang, Frank; Hubbard, Barbara; Jayne, Millard; King, Payton; Carter, Pauline; Carter, Scott; Xu, Youwen; Shea, Colleen; Muench, Lisa; Alexoff, David; Shumay, Elena; Schueller, Michael; Warner, Donald; Apelskog-Torres, Karen

2010-01-01

Reversible inhibitors of monoamine oxidase-A (RIMA) inhibit the breakdown of three major neurotransmitters, serotonin, norepinephrine and dopamine, offering a multi-neurotransmitter strategy for the treatment of depression. CX157 (3-fluoro-7-(2,2,2-trifluoroethoxy)phenoxathiin-10,10-dioxide) is a RIMA, which is currently in development for the treatment of major depressive disorder. We examined the degree and reversibility of the inhibition of brain monoamine oxidase-A (MAO-A) and plasma CX157 levels at different times after oral dosing to establish a dosing paradigm for future clinical efficacy studies, and to determine whether plasma CX157 levels reflect the degree of brain MAO-A inhibition. Brain MAO-A levels were measured with positron emission tomography (PET) imaging and [11C]clorgyline in 15 normal men after oral dosing of CX157 (20–80 mg). PET imaging was conducted after single and repeated doses of CX157 over a 24-h time course. We found that 60 and 80 mg doses of CX157 produced a robust dose-related inhibition (47–72%) of [11C]clorgyline binding to brain MAO-A at 2 h after administration and that brain MAO-A recovered completely by 24 h post drug. Plasma CX157 concentration was highly correlated with the inhibition of brain MAO-A (EC50: 19.3 ng/ml). Thus, CX157 is the first agent in the RIMA class with documented reversible inhibition of human brain MAO-A, supporting its classification as a RIMA, and the first RIMA with observed plasma levels that can serve as a biomarker for the degree of brain MAO-A inhibition. These data were used to establish the dosing regimen for a current clinical efficacy trial with CX157. PMID:19890267

29 CFR 1952.157 - Changes to approved plan.

Science.gov (United States)

2010-07-01

... (CONTINUED) APPROVED STATE PLANS FOR ENFORCEMENT OF STATE STANDARDS North Carolina § 1952.157 Changes to approved plan. (a) Legislation. (1) On March 29, 1994, the Assistant Secretary approved North Carolina's... section 17 of the Act as amended on November 5, 1990. (2) [Reserved] (b) The Voluntary Protection Program...

33 CFR 157.460 - Additional operational requirements for tank barges.

Science.gov (United States)

2010-07-01

... OF HOMELAND SECURITY (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT... Hulls Carrying Petroleum Oils § 157.460 Additional operational requirements for tank barges. (a...

Severe Outbreak of Sorbitol-Fermenting Escherichia coli O157 via Unpasteurized Milk and Farm Visits, Finland 2012.

Science.gov (United States)

Jaakkonen, A; Salmenlinna, S; Rimhanen-Finne, R; Lundström, H; Heinikainen, S; Hakkinen, M; Hallanvuo, S

2017-09-01

Shiga toxin-producing, sorbitol-fermenting Escherichia coli O157 (SF O157) has emerged as a cause of severe human illness. Despite frequent human findings, its transmission routes and reservoirs remain largely unknown. Foodborne transmission and reservoir in cattle have been suspected, but with limited supporting evidence. This study describes the outbreak of SF O157 that occurred in Finland in 2012. The outbreak originated from a recreational farm selling unpasteurized milk, as revealed by epidemiologic and microbiological investigations, and involved six hospitalized children and two asymptomatic adults with culture-confirmed infection. An identical strain of SF O157 was isolated from patients, cattle and the farm environment, and epidemiologic analysis suggested unpasteurized milk as the vehicle of transmission. This study reports the first milkborne outbreak of SF O157, provides supporting evidence of cattle as a reservoir and highlights the health risks related to the consumption of unpasteurized milk. © 2017 The Authors. Zoonoses and Public Health Published by Blackwell Verlag GmbH.

Lytic bacteriophages reduce Escherichia coli O157: H7 on fresh cut lettuce introduced through cross-contamination.

Science.gov (United States)

Ferguson, Sean; Roberts, Cheryl; Handy, Eric; Sharma, Manan

2013-01-01

The role of lytic bacteriophages in preventing cross contamination of produce has not been evaluated. A cocktail of three lytic phages specific for E. coli O157:H7 (EcoShield™) or a control (phosphate buffered saline, PBS) was applied to lettuce by either; (1) immersion of lettuce in 500 ml of EcoShield™ 8.3 log PFU/ml or 9.8 log PFU/ml for up to 2 min before inoculation with E. coli O157:H7; (2) spray-application of EcoShield™ (9.3 log PFU/ml) to lettuce after inoculation with E. coli O157:H7 (4.10 CFU/cm 2 ) following exposure to 50 μg/ml chlorine for 30 sec. After immersion studies, lettuce was spot-inoculated with E. coli O157:H7 (2.38 CFU/cm 2 ). Phage-treated, inoculated lettuce pieces were stored at 4°C for and analyzed for E. coli O157:H7 populations for up to 7 d. Immersion of lettuce in 9.8 log PFU/ml EcoShield™ for 2 min significantly (p PFU/ml) resulted in the deposition of high concentrations (7.8 log log PFU/cm 2 ) of bacteriophages on the surface of fresh cut lettuce, potentially contributing to the efficacy of the lytic phages on lettuce. Spraying phages on to inoculated fresh cut lettuce after being washed in hypochlorite solution was significantly more effective in reducing E. coli O157:H7 populations (2.22 log CFU/cm 2 ) on day 0 compared with control treatments (4.10 log CFU/cm 2 ). Both immersion and spray treatments provided protection from E. coli O157:H7 contamination on lettuce, but spray application of lytic bacteriophages to lettuce was more effective in immediately reducing E. coli O157:H7 populations fresh cut lettuce.

Anxiety- and depression-like behavior in mice lacking the CD157/BST1 gene, a risk factor for Parkinson’s disease

Directory of Open Access Journals (Sweden)

Olga eLopatina

2014-04-01

Full Text Available CD157, known as bone marrow stromal cell antigen-1, is a glycosylphosphatidylinositol-anchored ADP-ribosyl cyclase that supports the survival and function of B-lymphocytes and hematopoietic or intestinal stem cells. Although CD157/Bst1 is a risk locus in Parkinson’s disease (PD, little is known about the function of CD157 in the nervous system and contribution to PD progression. Here, we show that no apparent motor dysfunction was observed in young knockout (CD157-/- male mice under less aging-related effects on behaviors. CD157-/- mice exhibited anxiety-related and depression-like behaviors compared with wild-type mice. These behaviors were rescued through treatment with anti-psychiatric drugs and oxytocin. CD157 was weakly expressed in the amygdala and c-Fos immunoreactivity was less evident in CD157-/- mice than in wild-type mice. These results demonstrate for the first time that CD157 plays a role as a neuro-regulator and suggest a potential role in pre-motor symptoms in PD.

Modified Vero cell induced by Bifidobacterium bifidum inhibits enterohemorrhagic Escherichia coli O157:H7 cytopathic effect

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Tahamtan, Y.

2014-11-01

Full Text Available Enterohemorrhagic Escherichia coli (EHEC, such as E. coli O157:H7, are emerging food-borne pathogens worldwide. This micro-organism can damage the epithelial tissue of the large intestine. The cytotoxic effects can be neutralized by probiotics such as Bifidobacterium bifidum. Probiotics are viable cells that have beneficial effects on the health of the host. The preventing activity of B. bifidum against E. coli O157 was studied using a Vero cell model. Vero cell was pretreated with viable B. bifidum and incubated for either 3 h to 24 h and then collected from the cell to make modified Vero cell (MVC. Indirect antibacterial effects of B. bifidum were demonstrated by reduction of attachment of E. coli O157:H7 to MVC. The maximum reduction was resulted in pretreatment of Vero cell with B. bifidum for 24 h before infection. B. bifidum attenuated E. coli O157:H7 attachment to MVC up to 10 days of incubation. To our knowledge, MCV prevented Vero cell line injury induced by E. coli O157:H7. Therefore, B. bifidum can be used for inhibition of E. coli O157:H7 cytopathic effect (CPE in Vero cell model, even as pretreatment of the cell line.

33 CFR 157.158 - COW operations: Changed characteristics.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false COW operations: Changed... CARRYING OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.158 COW operations: Changed characteristics. The COW system may be operated with characteristics that do not meet those...

18 CFR 157.218 - Changes in customer name.

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2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Changes in customer... Act for Certain Transactions and Abandonment § 157.218 Changes in customer name. (a) Automatic... reflect the change in the name of an existing customer, if the certificate holder has filed any necessary...

Relative nephroprotection during Escherichia coli O157:H7 infections: association with intravenous volume expansion.

Science.gov (United States)

Ake, Julie A; Jelacic, Srdjan; Ciol, Marcia A; Watkins, Sandra L; Murray, Karen F; Christie, Dennis L; Klein, Eileen J; Tarr, Phillip I

2005-06-01

The hemolytic uremic syndrome (HUS) consists of hemolytic anemia, thrombocytopenia, and renal failure. HUS is often precipitated by gastrointestinal infection with Shiga toxin-producing Escherichia coli and is characterized by a variety of prothrombotic host abnormalities. In much of the world, E coli O157:H7 is the major cause of HUS. HUS can be categorized as either oligoanuric (which probably signifies acute tubular necrosis) or nonoligoanuric. Children with oligoanuric renal failure during HUS generally require dialysis, have more complicated courses, and are probably at increased risk for chronic sequelae than are children who experience nonoligoanuric HUS. Oligoanuric HUS should be avoided, if possible. The presentation to medical care of a child with definite or possible E coli O157:H7 infections but before HUS ensues affords a potential opportunity to ameliorate the course of the subsequent renal failure. However, it is not known whether events that occur early in E coli O157:H7 infections, particularly measures to expand circulating volume, affect the likelihood of experiencing oligoanuric HUS if renal failure develops. We attempted to assess whether pre-HUS interventions and events, especially the volume and sodium content of intravenous fluids administered early in illness, affect the risk for developing oligoanuric HUS after E coli O157:H7 infections. We performed a prospective cohort study of 29 children with HUS that was confirmed microbiologically to be caused by E coli O157:H7. Infected children were enrolled when they presented with acute bloody diarrhea or as contacts of patients who were known to be infected with E coli O157:H7, or if they had culture-confirmed infection, or if they presented with HUS. HUS was defined as hemolytic anemia (hematocrit parenteral fluid administered, were recorded and entered into analysis. Estimates of odds ratios were adjusted for possible confounding effects using logistic regression analysis. Twenty-nine children

Use of Bacteriophages to Control Escherichia coli O157:H7 in Domestic Ruminants, Meat Products, and Fruits and Vegetables.

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Wang, Lili; Qu, Kunli; Li, Xiaoyu; Cao, Zhenhui; Wang, Xitao; Li, Zhen; Song, Yaxiong; Xu, Yongping

2017-09-01

Escherichia coli O157:H7 is an important foodborne pathogen that causes severe bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Ruminant manure is a primary source of E. coli O157:H7 contaminating the environment and food sources. Therefore, effective interventions targeted at reducing the prevalence of fecal excretion of E. coli O157:H7 by cattle and sheep and the elimination of E. coli O157:H7 contamination of meat products as well as fruits and vegetables are required. Bacteriophages offer the prospect of sustainable alternative approaches against bacterial pathogens with the flexibility of being applied therapeutically or for biological control purposes. This article reviews the use of phages administered orally or rectally to ruminants and by spraying or immersion of fruits and vegetables as an antimicrobial strategy for controlling E. coli O157:H7. The few reports available demonstrate the potential of phage therapy to reduce E. coli O157:H7 carriage in cattle and sheep, and preparation of commercial phage products was recently launched into commercial markets. However, a better ecological understanding of the phage E. coli O157:H7 will improve antimicrobial effectiveness of phages for elimination of E. coli O157:H7 in vivo.

Comparative Effect of Heat Shock on Survival of O157:H7 and Non-O157 Shiga Toxigenic Escherichia coli and Salmonella in Lean Beef with or without Moisture-Enhancing Ingredients.

Science.gov (United States)

Vasan, Akhila; Ingham, Steven C; Ingham, Barbara H

2017-06-01

Thermal tolerance of pathogenic bacteria has been shown to increase after exposure to sublethal elevated temperatures, or heat shock. We evaluated the effect of heat shock at 48°C on thermal tolerance (D 55°C ) of cocktails of O157 and non-O157 Shiga toxigenic Escherichia coli (STEC) and Salmonella in lean ground beef with or without moisture-enhancing ingredients. Beef was moisture enhanced to 110% (w) with a 5% NaCl-2.5% sodium tripolyphosphate (w/w) brine. Meat, with or without added brine, was inoculated (∼10 8 CFU/g) and heat shocked at 48°C for 0, 5, or 30 min, followed by isothermal heating at 55°C. Inoculated control samples were unenhanced and were not subject to heat shock. From the linear portion of the log CFU per gram surviving cells over time plots, D 55°C -values (minutes) were calculated. D 55°C was 20.43, 28.78, and 21.15 min for O157, non-O157, and Salmonella controls, respectively. Overall, heat shock significantly increased D 55°C , regardless of pathogen (P moisture-enhanced meat (P Moisture-enhancing ingredients significantly increased D 55°C , regardless of pathogen (P moisture-enhanced beef products.

Detection of Escherichia Coli O157:H7 in Fecal Samples in Meat Goats

Science.gov (United States)

Mobley, Ray; Madden, Uford; Brooks-Walter, Alexis

2004-01-01

Studies have reported the isolation of Escherichia coli (E. coli)O157:H7 from pork, lamb and poultry products, and from other animals including deer, horses, dogs, birds and humans. There is limited or no information on the presence of the organism in goats. The objectives of this study were to determine if E. coli O157:H7 was naturally occurring…

Irradiation effect of escherichia coli O157 : H7 in meats

International Nuclear Information System (INIS)

Ito, Hitoshi; Harsojo

1998-01-01

Escherichia coli O157 : H7 is a rapidly emerging food-born pathogen which has been linked to outbreaks of hemorrhagic diarrhea in Japan, USA or many European countries. From this study, two strains of E. coli O157 : H7 were isolated from beef and chicken meats in each one sample of 4 replicates. Some of the biochemical characteristics of these isolates were different from type strain IID959. These isolates could grow quickly at 10degC on cultivation of nutrient agar. D 10 value of these isolates were obtained to be 0.06kGy in 0.067M phosphate buffer suspension which were highly sensitive than D 10 value of 0.12kGy on type strain IID959. On the irradiation effect of type strain IID959 in ground beef, D 10 value was obtained as 0.26kGy at fresh condition and 0.46kGy at frozen condition, respectively. From these results, necessary dose for elimination of E. coli O157 : H7 was decided as 1.5kGy for fresh meats and 3kGy for frozen meats. (author)

Development, validation, and standardization of polymerase chain reaction-based detection of E-coli O157

DEFF Research Database (Denmark)

Abdulmawjood, A.; Bulte, M.; Roth, S.

2004-01-01

A diagnostic polymerase chain reaction assay was developed for the detection of E. coli O157 as the first part of a multicenter validation and standardization project. The assay is based on amplification of sequences of the rfbE O157 gene and includes an internal amplification control. The select...

Patient survival and tumor characteristics associated with CHEK2:p.I157T - findings from the Breast Cancer Association Consortium.

Science.gov (United States)

Muranen, Taru A; Blomqvist, Carl; Dörk, Thilo; Jakubowska, Anna; Heikkilä, Päivi; Fagerholm, Rainer; Greco, Dario; Aittomäki, Kristiina; Bojesen, Stig E; Shah, Mitul; Dunning, Alison M; Rhenius, Valerie; Hall, Per; Czene, Kamila; Brand, Judith S; Darabi, Hatef; Chang-Claude, Jenny; Rudolph, Anja; Nordestgaard, Børge G; Couch, Fergus J; Hart, Steven N; Figueroa, Jonine; García-Closas, Montserrat; Fasching, Peter A; Beckmann, Matthias W; Li, Jingmei; Liu, Jianjun; Andrulis, Irene L; Winqvist, Robert; Pylkäs, Katri; Mannermaa, Arto; Kataja, Vesa; Lindblom, Annika; Margolin, Sara; Lubinski, Jan; Dubrowinskaja, Natalia; Bolla, Manjeet K; Dennis, Joe; Michailidou, Kyriaki; Wang, Qin; Easton, Douglas F; Pharoah, Paul D P; Schmidt, Marjanka K; Nevanlinna, Heli

2016-10-03

P.I157T is a CHEK2 missense mutation associated with a modest increase in breast cancer risk. Previously, another CHEK2 mutation, the protein truncating c.1100delC has been associated with poor prognosis of breast cancer patients. Here, we have investigated patient survival and characteristics of breast tumors of germ line p.I157T carriers. We included in the analyses 26,801 European female breast cancer patients from 15 studies participating in the Breast Cancer Association Consortium. We analyzed the association between p.I157T and the clinico-pathological breast cancer characteristics by comparing the p.I157T carrier tumors to non-carrier and c.1100delC carrier tumors. Similarly, we investigated the p.I157T associated risk of early death, breast cancer-associated death, distant metastasis, locoregional relapse and second breast cancer using Cox proportional hazards models. Additionally, we explored the p.I157T-associated genomic gene expression profile using data from breast tumors of 183 Finnish female breast cancer patients (ten p.I157T carriers) (GEO: GSE24450). Differential gene expression analysis was performed using a moderated t test. Functional enrichment was investigated using the DAVID functional annotation tool and gene set enrichment analysis (GSEA). The tumors were classified into molecular subtypes according to the St Gallen 2013 criteria and the PAM50 gene expression signature. P.I157T was not associated with increased risk of early death, breast cancer-associated death or distant metastasis relapse, and there was a significant difference in prognosis associated with the two CHEK2 mutations, p.I157T and c.1100delC. Furthermore, p.I157T was associated with lobular histological type and clinico-pathological markers of good prognosis, such as ER and PR expression, low TP53 expression and low grade. Gene expression analysis suggested luminal A to be the most common subtype for p.I157T carriers and CDH1 (cadherin 1) target genes to be significantly

Rapid and selective detection of E. coli O157:H7 combining phagomagnetic separation with enzymatic colorimetry.

Science.gov (United States)

Zhang, Yun; Yan, Chenghui; Yang, Hang; Yu, Junping; Wei, Hongping

2017-11-01

Mammal IgG antibodies are normally used in conventional immunoassays for E. coli O157:H7, which could lead to false positive results from the presence of protein A producing S. aureus. In this study, a natural specific bacteriophage was isolated and then conjugated with magnetic beads as a capture element in a sandwich format for the rapid and selective detection of E. coli O157:H7. To the best of our knowledge, it was the first time to utilize a natural bacteriophage to develop a phagomagnetic separation combined with colorimetric assay for E. coli O157:H7. The method has an overall time less than 2h with a detection limit of 4.9×10 4 CFU/mL. No interference from S. aureus was observed. Furthermore, the proposed method was successfully applied to detect E. coli O157:H7 in spiked skim milk. The proposed detection system provided a potential method for E. coli O157:H7 and other pathogenic bacteria in food samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Escherichia coli O157:H7 Outbreak Associated with Restaurant Beef Grinding.

Science.gov (United States)

Torso, Lauren M; Voorhees, Ronald E; Forest, Stephen A; Gordon, Andrew Z; Silvestri, Sharon A; Kissler, Bonnie; Schlackman, Jessica; Sandt, Carol H; Toma, Paul; Bachert, Joel; Mertz, Kristen J; Harrison, Lee H

2015-07-01

Escherichia coli O157:H7 is a common cause of foodborne illness in the United States. Beef ground at establishments regulated by the U.S. Department of Agriculture, Food Safety and Inspection Service is routinely tested for E. coli O157:H7. Prior to December 2013, boxed beef product (wholesale cuts of beef, such as beef loin, packaged into bags and boxed for shipping) was not always tested for this pathogen. Downstream processors or retailers may grind the product; and, if the ground beef is not cooked to the recommended temperature, pathogens on the exterior of the beef introduced to the interior through grinding may survive. On 18 October 2013, the Allegheny County Health Department identified two E. coli O157:H7 cases, both of whom were food handlers at restaurant A, a restaurant that ground locally produced boxed beef for hamburgers on site. Case finding was conducted through public messaging, employee surveys, and disease surveillance. All potential cases were interviewed using a standard questionnaire. A confirmed case was defined as laboratory-confirmed E. coli O157:H7 with exposure to restaurant A. A probable case was defined as a patient with compatible symptoms and exposure to restaurant A but without laboratory confirmation. All human and food isolates were characterized by pulsed-field gel electrophoresis and multilocus variable-number tandem repeat analysis. The analysis identified 14 confirmed and 10 probable cases of E. coli; 18 nonintact ground beef samples tested positive for E. coli O157:H7. Nine confirmed cases were restaurant A employees. All confirmed cases recalled eating a restaurant A hamburger in the 10 days before illness onset; most cases reported consuming medium to rare hamburgers. Multiple pulsed-field gel electrophoresis and multilocus variable-number tandem repeat analysis patterns were identified among both the human and ground beef isolates, and the patient isolates matched those found in ground beef samples. Restaurant A

33 CFR 157.410 - Emergency lightering requirements for oil tankers.

Science.gov (United States)

2010-07-01

... HOMELAND SECURITY (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK... Petroleum Oils § 157.410 Emergency lightering requirements for oil tankers. Each oil tanker, to which this...

33 CFR 157.415 - Bridge resource management policy and procedures.

Science.gov (United States)

2010-07-01

... HOMELAND SECURITY (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK... Petroleum Oils § 157.415 Bridge resource management policy and procedures. (a) Not later than February 1...

Assumptions of acceptance sampling and the implications for lot contamination: Escherichia coli O157 in lots of Australian manufacturing beef.

Science.gov (United States)

Kiermeier, Andreas; Mellor, Glen; Barlow, Robert; Jenson, Ian

2011-04-01

The aims of this work were to determine the distribution and concentration of Escherichia coli O157 in lots of beef destined for grinding (manufacturing beef) that failed to meet Australian requirements for export, to use these data to better understand the performance of sampling plans based on the binomial distribution, and to consider alternative approaches for evaluating sampling plans. For each of five lots from which E. coli O157 had been detected, 900 samples from the external carcass surface were tested. E. coli O157 was not detected in three lots, whereas in two lots E. coli O157 was detected in 2 and 74 samples. For lots in which E. coli O157 was not detected in the present study, the E. coli O157 level was estimated to be contaminated carton, the total number of E. coli O157 cells was estimated to be 813. In the two lots in which E. coli O157 was detected, the pathogen was detected in 1 of 12 and 2 of 12 cartons. The use of acceptance sampling plans based on a binomial distribution can provide a falsely optimistic view of the value of sampling as a control measure when applied to assessment of E. coli O157 contamination in manufacturing beef. Alternative approaches to understanding sampling plans, which do not assume homogeneous contamination throughout the lot, appear more realistic. These results indicate that despite the application of stringent sampling plans, sampling and testing approaches are inefficient for controlling microbiological quality.

An aptamer-based biosensor for colorimetric detection of Escherichia coli O157:H7.

Directory of Open Access Journals (Sweden)

Wenhe Wu

Full Text Available BACKGROUND: An aptamer based biosensor (aptasensor was developed and evaluated for rapid colorimetric detection of Escherichia coli (E. coli O157:H7. METHODOLOGY/PRINCIPAL FINDINGS: The aptasensor was assembled by modifying the truncated lipopolysaccharides (LPS-binding aptamer on the surface of nanoscale polydiacetylene (PDA vesicle using peptide bonding between the carboxyl group of the vesicle and the amine group of the aptamer. Molecular recognition between E. coli O157:H7 and aptamer at the interface of the vesicle lead to blue-red transition of PDA which was readily visible to the naked eyes and could be quantified by colorimetric responses (CR. Confocal laser scanning microscope (CLSM and transmission electron microscopy (TEM was used to confirm the specific interactions between the truncated aptamer and E. coli O157:H7. The aptasensor could detect cellular concentrations in a range of 10(4~ 10(8 colony-forming units (CFU/ml within 2 hours and its specificity was 100% for detection of E. coli O157:H7. Compared with the standard culture method, the correspondent rate was 98.5% for the detection of E. coli O157:H7 on 203 clinical fecal specimens with our aptasensor. CONCLUSIONS: The new aptasensor represents a significant advancement in detection capabilities based on the combination of nucleic acid aptamer with PDA vesicle, and offers a specific and convenient screening method for the detection of pathogenic bacteria. This technic could also be applied in areas from clinical analysis to biological terrorism defense, especially in low-resource settings.

Threshold-dependent repression of SPL gene expression by miR156/miR157 controls vegetative phase change in Arabidopsis thaliana.

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Jia He

2018-04-01

Full Text Available Vegetative phase change is regulated by a decrease in the abundance of the miRNAs, miR156 and miR157, and the resulting increase in the expression of their targets, SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL transcription factors. To determine how miR156/miR157 specify the quantitative and qualitative changes in leaf morphology that occur during vegetative phase change, we measured their abundance in successive leaves and characterized the phenotype of mutations in different MIR156 and MIR157 genes. miR156/miR157 decline rapidly between leaf 1&2 and leaf 3 and decrease more slowly after this point. The amount of miR156/miR157 in leaves 1&2 greatly exceeds the threshold required to specify their identity. Subsequent leaves have relatively low levels of miR156/miR157 and are sensitive to small changes in their abundance. In these later-formed leaves, the amount of miR156/miR157 is close to the threshold required to specify juvenile vs. adult identity; a relatively small decrease in the abundance of miR156/157 in these leaves produces a disproportionately large increase in SPL proteins and a significant change in leaf morphology. miR157 is more abundant than miR156 but has a smaller effect on shoot morphology and SPL gene expression than miR156. This may be attributable to the inefficiency with which miR157 is loaded onto AGO1, as well as to the presence of an extra nucleotide at the 5' end of miR157 that is mis-paired in the miR157:SPL13 duplex. miR156 represses different targets by different mechanisms: it regulates SPL9 by a combination of transcript cleavage and translational repression and regulates SPL13 primarily by translational repression. Our results offer a molecular explanation for the changes in leaf morphology that occur during shoot development in Arabidopsis and provide new insights into the mechanism by which miR156 and miR157 regulate gene expression.

The Development of a Portable SPR Bioanalyzer for Sensitive Detection of Escherichia coli O157:H7

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Shun Wang

2016-11-01

Full Text Available The purpose of this study was to develop a portable surface plasmon resonance (SPR bioanalyzer for the sensitive detection of Escherichia coli O157:H7 in comparison with an enzyme-linked immunosorbent assay (ELISA. The experimental setup mainly consisted of an integrated biosensor and a homemade microfluidic cell with a three-way solenoid valve. In order to detect Escherichia coli O157:H7 using the SPR immunoassay, 3-mercaptopropionic acid (3-MPA was chemisorbed onto a gold surface via covalent bond for the immobilization of biological species. 1-ethyl-3-(3-dimethylaminopropyl carbodiimide hydrochloride (EDC and N-hydroxysuccinimide (NHS were used as crosslinker reagents to enable the reaction between 3-MPA and Escherichia coli O157:H7 antibodies by covalent –CO–NH– amide bonding. The experimental results were obtained from the Escherichia coli O157:H7 positive samples prepared by 10-, 20-, 40-, 80-, and 160-fold dilution respectively, which show that a good linear relationship with the correlation coefficient R of 0.982 existed between the response units from the portable SPR bioanalyzer and the concentration of Escherichia coli O157:H7 positive samples. Moreover, the theoretical detection limit of 1.87 × 103 cfu/mL was calculated from the positive control samples. Compared with the Escherichia coli O157:H7 ELISA kit, the sensitivity of this portable SPR bioanalyzer is four orders of magnitude higher than the ELISA kit. The results demonstrate that the portable SPR bioanalyzer could provide an alternative method for the quantitative and sensitive determination of Escherichia coli O157:H7 in field.

Antagonistic Activity of Probiotic Bacteria Isolated from Traditional Dairy Products against E. coli O157:H7

Directory of Open Access Journals (Sweden)

Maryam Rahimpour Hesari

2017-10-01

Full Text Available Background:    Probiotics are living microorganisms that have useful effects on health of digestive system when acquired in a defined dosage. E. coli O157:H7 is known as one of the most important agents of diarrhea in developing countries. Therefore, attention to the treatment of such gastrointestinal disease is essential. The aim of this study was to determine antagonistic activity of food born lactobacilli against E. coli O157:H7.Methods:     Lactobacilli were isolated from traditional dairy products (yogurt and buttermilk samples. Then, they were characterized using biochemical and molecular tests. Bifidobacterium bifidum PTCC 1644 was obtained from the microbial collection of Iranian Research Organization for Science and Technology in Lyophilized form. Similarly, E. coli O157:H7 PTCC12900 was obtained from faculty of veterinary medicine university of Tehran. The antagonistic activity of probiotics supernatants against E. coli O157:H7 was investigated using the disk diffusion agar, well diffusion agar and pour plate methods.Results:   The isolates were characterized as Lactobacillus plantarum and Lactobacillus fermentum. All isolates showed antagonistic activities against E. coli O157:H7 in all of the three methods, where the activity of L. plantarum and B. bidifum PTCC 1644 was greater than that of L. fermentum. Conclusion:   Metabolites produced by the probiotic bacteria are able to inhibit the growth of E. coli O157:H7. This can be an important solution for the prevention and treatment of E. coli O157:H7 infection and ultimately improve human health.

Assessments of Total and Viable Escherichia coli O157:H7 on Field and Laboratory Grown Lettuce

Science.gov (United States)

Moyne, Anne-Laure; Harris, Linda J.; Marco, Maria L.

2013-01-01

Leafy green produce has been associated with numerous outbreaks of foodborne illness caused by strains of Escherichia coli O157:H7. While the amounts of culturable E. coli O157:H7 rapidly decline after introduction onto lettuce in the field, it remains to be determined whether the reduction in cell numbers is due to losses in cell viability, cell injury and a subsequent inability to be detected by standard laboratory culturing methods, or a lack of adherence and hence rapid removal of the organism from the plants during application. To assess which of these options is most relevant for E. coli O157:H7 on leafy green produce, we developed and applied a propidium monoazide (PMA) real-time PCR assay to quantify viable (with PMA) and total (without PMA) E. coli O157:H7 cells on growth chamber and field-grown lettuce. E. coli O157:H7, suspended in 0.1% peptone, was inoculated onto 4-week-old lettuce plants at a level of approximately 106 CFU/plant. In the growth chamber at low relative humidity (30%), culturable amounts of the nontoxigenic E. coli O157:H7 strain ATCC 700728 and the virulent strain EC4045 declined 100 to 1000-fold in 24 h. Fewer E. coli O157:H7 cells survived when applied onto plants in droplets with a pipette compared with a fine spray inoculation. Total cells for both strains were equivalent to inoculum levels for 7 days after application, and viable cell quantities determined by PMA real-time PCR were approximately 104 greater than found by colony enumeration. Within 2 h after application onto plants in the field, the number of culturable E. coli ATCC 700728 was reduced by up to 1000-fold, whereas PCR-based assessments showed that total cell amounts were equivalent to inoculum levels. These findings show that shortly after inoculation onto plants, the majority of E. coli O157:H7 cells either die or are no longer culturable. PMID:23936235

A rapid two dot filter assay for the detection of E. coli O157 in water samples.

Science.gov (United States)

Kamma, Sujatha; Tang, Lily; Leung, Kelvin; Ashton, Edie; Newman, Norman; Suresh, Mavanur R

2008-07-31

E. coli O157:H7 is an enterohemorrhagic bacteria that cause deadly water-borne infections implicated in outbreaks of a wide spectrum of human gastrointestinal diseases. It is therefore important to have a rapid convenient, simple and sensitive range of detection of E. coli O157:H7. A new E. coli O157 MAb designated P124 was developed for ultrasensitive detection of E. coli O157 in water, apple juice and beef for routine use. A prototype filter dot assay was designed with anti-E. coli O157 MAb bound to 0.2 microm nitrocellulose filter disk as the capture antibody. A 100 ml water sample spiked with 1-50 CFU of E. coli O157 either in the presence or absence of other non-specific bacteria were filtered for capture of the pathogen on the antibody coated nitrocellulose disk. The detection of the pathogen was successfully accomplished by the same antibody both as a capture and detecting antibody as a homosandwich. In a non-enriched format, detection of E. coli was possible with a sensitivity of 2500 CFU/100 ml. Ultrasensitive detection of ~1 CFU/100 ml sample could be achieved by a prior pathogen enrichment step before the addition of the labeled antibody. The design of this diagnostic test is based on the common architecture of all bacteria, viruses and spores, namely the manifestation of repeat lipopolysaccharide epitopes on the surface. We have developed an easy-to-use two dot visual filter assay for translation into current water testing in public health laboratories to detect E. coli O157:H7. In a 5 h assay approximately 1 CFU and approximately 5 CFU of E. coli O157 could be detected in 100 ml of water or juice and lake samples respectively. This simple homosandwich enrichment strategy can also be used to detect low levels of other water-borne pathogens.

Development and Validation of A Spectrofluorimetric Determination of Calf Thymus DNA Using a Terbium-Danofloxacin Probe

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Naser Soltani

2016-03-01

Full Text Available Background: Analysis of biomolecules is required in many biomedical research areas. A spectrofluorimetric method is proposed for determination of calf thymus DNA (ctDNA based on the fluorescence enhancement of terbium-danofloxacin (Tb3+-Dano in the presence of ctDNA. Methods: A probe with maximum excitation and emission wavelengths of 347 nm and 545 nm, respectively, was developed. The enhanced fluorescence intensity of Tb3+-Dano system was proportional to the concentration of ctDNA. The effective factors and the optimum conditions for the determination of ctDNA were studied. Under the optimum conditions of [Tris buffer]= 0.01 mol L-1 (pH 7.8, [ Tb3+]= 1×10-5 mol L-1 and [Dano]= 5×10-5 mol L-1, the maximum response was achieved. The developed method was evaluated in terms of accuracy, precision and limit of detection. Results: The linear concentration range for quantification of ctDNA was 36-3289 ng mL-1 and the detection limit (S/N=3 was 8 ng mL-1. The concentration of DNA extracted from Escherichia coli as an extracted sample was also determined using the developed probe. The concentration of DNA in extracted sample was determined using UV assay and developed method, the results were satisfactory. Conclusion: The proposed method is a simple, practical and relatively interference free method to follow up the concentrations of ctDNA.

Antibacterial activities of wasabi against Escherichia coli O157:H7 and Staphylococcus aureus

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Zhongjing Lu

2016-09-01

Full Text Available Escherichia coli O157:H7 and Staphylococcus aureus are two of the major pathogens frequently involved in foodborne outbreaks. Control of these pathogens in foods is essential to food safety. It is of great interest in the use of natural antimicrobial compounds present in edible plants to control foodborne pathogens as consumers prefer more natural green foods. Allyl isothiocyanate (AITC is an antimicrobial compound naturally present in wasabi (Japanese horseradish and several other edible plants. Although the antibacterial effects of pure AITC and wasabi extract (essential oil against several bacteria have been reported, the antibacterial property of natural wasabi has not been well studied. This study investigated the antibacterial activities of wasabi as well as AITC against E. coli O157:H7 and S. aureus. Chemical analysis showed that AITC is the major isothiocyanate in wasabi. The AITC concentration in the wasabi powder used in this study was 5.91±0.59 mg/g. The minimum inhibitory concentration (MIC of wasabi against E. coli O157:H7 or S. aureus was 1% (or 10 mg/ml. Wasabi at 4% displayed higher bactericidal activity against S. aureus than against E. coli O157:H7. The MIC of AITC against either pathogen was between 10 and 100 µg/ml. AITC at 500 µg/ml was bactericidal against both pathogens while AITC at 1000 µg/ml eliminated E. coli O157:H7 much faster than S. aureus. The results from this study showed that wasabi has strong antibacterial property and has high potential to effectively control E. coli O157:H7 and S. aureus in foods. The antibacterial property along with its natural green color, unique flavor, and advantage to safeguard foods at the point of ingestion makes wasabi a promising natural edible antibacterial plant. The results from this study may be of significant interest to the food industry as they develop new and safe foods. These results may also stimulate more research to evaluate the antibacterial effect of wasabi

Antibacterial Activities of Wasabi against Escherichia coli O157:H7 and Staphylococcus aureus.

Science.gov (United States)

Lu, Zhongjing; Dockery, Christopher R; Crosby, Michael; Chavarria, Katherine; Patterson, Brett; Giedd, Matthew

2016-01-01

Escherichia coli O157:H7 and Staphylococcus aureus are two of the major pathogens frequently involved in foodborne outbreaks. Control of these pathogens in foods is essential to food safety. It is of great interest in the use of natural antimicrobial compounds present in edible plants to control foodborne pathogens as consumers prefer more natural "green" foods. Allyl isothiocyanate (AITC) is an antimicrobial compound naturally present in wasabi (Japanese horseradish) and several other edible plants. Although the antibacterial effects of pure AITC and wasabi extract (essential oil) against several bacteria have been reported, the antibacterial property of natural wasabi has not been well studied. This study investigated the antibacterial activities of wasabi as well as AITC against E . coli O157:H7 and S . aureus . Chemical analysis showed that AITC is the major isothiocyanate in wasabi. The AITC concentration in the wasabi powder used in this study was 5.91 ± 0.59 mg/g. The minimum inhibitory concentration (MIC) of wasabi against E. coli O157:H7 or S. aureus was 1% (or 10 mg/ml). Wasabi at 4% displayed higher bactericidal activity against S. aureus than against E. coli O157:H7. The MIC of AITC against either pathogen was between 10 and 100 μg/ml. AITC at 500 μg/ml was bactericidal against both pathogens while AITC at 1000 μg/ml eliminated E. coli O157:H7 much faster than S. aureus . The results from this study showed that wasabi has strong antibacterial property and has high potential to effectively control E. coli O157:H7 and S. aureus in foods. The antibacterial property along with its natural green color, unique flavor, and advantage to safeguard foods at the point of ingestion makes wasabi a promising natural edible antibacterial plant. The results from this study may be of significant interest to the food industry as they develop new and safe foods. These results may also stimulate more research to evaluate the antibacterial effect of wasabi against other

Gene Expression during Survival of Escherichia coli O157:H7 in Soil and Water

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Ashley D. Duffitt

2011-01-01

Full Text Available The in vitro survival of Escherichia coli O157:H7 at 15∘C under two experimental conditions (sterile soil and sterile natural water was examined. DNA microarrays of the entire set of E. coli O157:H7 genes were used to measure the genomic expression patterns after 14 days. Although the populations declined, some E. coli O157:H7 cells survived in sterile stream water up to 234 days and in sterile soil for up to 179 days. Cells incubated in soil microcosms for 14 days expressed genes for antibiotic resistance, biosynthesis, DNA replication and modification, metabolism, phages, transposons, plasmids, pathogenesis and virulence, antibiotic resistance, ribosomal proteins, the stress response, transcription, translation, and transport and binding proteins at significantly higher levels than cells grown in Luria broth. These results suggest that E. coli O157:H7 may develop a different phenotype during transport through the environment. Furthermore, this pathogen may become more resistant to antibiotics making subsequent infections more difficult to treat.

40 CFR 93.157 - Frequency of conformity determinations.

Science.gov (United States)

2010-07-01

... convenience of the user, the revised text is set forth as follows: § 93.157 Reevaluation of conformity. (a... were below the limits in § 93.153(b) and changes to the action would result in the total emissions from the action being above the limits in § 93.153(b), then the Federal agency must make a conformity...

Correction of 157-nm lens based on phase ring aberration extraction method

Science.gov (United States)

Meute, Jeff; Rich, Georgia K.; Conley, Will; Smith, Bruce W.; Zavyalova, Lena V.; Cashmore, Julian S.; Ashworth, Dominic; Webb, James E.; Rich, Lisa

2004-05-01

Early manufacture and use of 157nm high NA lenses has presented significant challenges including: intrinsic birefringence correction, control of optical surface contamination, and the use of relatively unproven materials, coatings, and metrology. Many of these issues were addressed during the manufacture and use of International SEMATECH"s 0.85NA lens. Most significantly, we were the first to employ 157nm phase measurement interferometry (PMI) and birefringence modeling software for lens optimization. These efforts yielded significant wavefront improvement and produced one of the best wavefront-corrected 157nm lenses to date. After applying the best practices to the manufacture of the lens, we still had to overcome the difficulties of integrating the lens into the tool platform at International SEMATECH instead of at the supplier facility. After lens integration, alignment, and field optimization were complete, conventional lithography and phase ring aberration extraction techniques were used to characterize system performance. These techniques suggested a wavefront error of approximately 0.05 waves RMS--much larger than the 0.03 waves RMS predicted by 157nm PMI. In-situ wavefront correction was planned for in the early stages of this project to mitigate risks introduced by the use of development materials and techniques and field integration of the lens. In this publication, we document the development and use of a phase ring aberration extraction method for characterizing imaging performance and a technique for correcting aberrations with the addition of an optical compensation plate. Imaging results before and after the lens correction are presented and differences between actual and predicted results are discussed.

Investigation of concentration-dependence of thermodynamic properties of lanthanum, yttrium, scandium and terbium in eutectic LiCl-KCl molten salt

Energy Technology Data Exchange (ETDEWEB)

Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo, E-mail: zhang.3558@osu.edu

2016-09-15

Thermodynamic properties of rare earth metals in LiCl-KCl molten salt electrolyte are crucial to the development of electrochemical separation for the treatment of used nuclear fuels. In the present study, activity coefficient, apparent potential, and diffusion coefficient of lanthanum, yttrium, scandium, and terbium in the molten salt (58 at% LiCl and 42 at% KCl) were calculated by the method of molecular dynamics simulation up to a concentration around 3 at% at temperatures of 723 K and 773 K. It was found that the activity coefficient and the apparent potential increase with the species concentration while diffusion coefficient shows a trend of increase followed by decrease. The calculated results were validated by available measurement data of dilution cases. This research extends the range of data to a wide component and would provide further insight to the pyroprocessing design and safeguards. - Highlights: • Investigation of activity coefficient, apparent potential and diffusion coefficient at different concentrations. • MD simulation was studied for the calculation of thermodynamic properties of rare earth elements in molten salt. • The present study is a pioneering work focusing on the concentration dependence of thermodynamic properties.

42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

Science.gov (United States)

2010-10-01

... test; Type C supplied-air respirator, pressure-demand class; minimum requirements. (a) The static... 42 Public Health 1 2010-10-01 2010-10-01 false Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum requirements. 84.157 Section 84.157 Public Health PUBLIC HEALTH...

Inactivation of Escherichia coli O157:H7 on stainless steel upon exposure to Paenibacillus polymyxa biofilms.

Science.gov (United States)

Kim, Seonhwa; Bang, Jihyun; Kim, Hoikyung; Beuchat, Larry R; Ryu, Jee-Hoon

2013-11-01

We investigated the potential use of biofilm formed by a competitive-exclusion (CE) microorganism to inactivate Escherichia coli O157:H7 on a stainless steel surface. Five microorganisms showing inhibitory activities against E. coli O157:H7 were isolated from vegetable seeds and sprouts. The microorganism with the greatest antimicrobial activity was identified as Paenibacillus polymyxa (strain T5). In tryptic soy broth (TSB), strain T5 reached a higher population at 25 °C than at 12 or 37 °C without losing inhibitory activity against E. coli O157:H7. When P. polymyxa (6 log CFU/mL) was co-cultured with E. coli O157:H7 (2, 3, 4, or 5 log CFU/mL) in TSB at 25 °C, the number of E. coli O157:H7 decreased significantly within 24h. P. polymyxa formed a biofilm on stainless steel coupons (SSCs) in TSB at 25 °C within 24h, and cells in biofilms, compared to attached cells without biofilm formation, showed significantly increased resistance to a dry environment (43% relative humidity [RH]). With the exception of an inoculum of 4 log CFU/coupon at 100% RH, upon exposure to biofilm formed by P. polymyxa on SSCs, populations of E. coli O157:H7 (2, 4, or 6 log CFU/coupon) were significantly reduced within 48 h. Most notably, when E. coli O157:H7 at 2 log CFU/coupon was applied to SSCs on which P. polymyxa biofilm had formed, it was inactivated within 1h, regardless of RH. These results will be useful when developing strategies using biofilms produced by competitive exclusion microorganisms to inactivate foodborne pathogens in food processing environments. © 2013.

Control of VTEC O157 and Campylobacter jejuni/coli on cattle farms : Effective interventions and implementation

NARCIS (Netherlands)

Ellis-Iversen, J

2009-01-01

Verocytotoxogenic E. coli O157 (VTEC O157) and Campylobacter jejuni/coli are zoonotic pathogens of public health importance, which are commonly carried and shed by cattle. Control at farm level needed isto limit shedding and contamination of the environment and the human food chain. On- farm risk

Internalization of E. coli O157:H7 in spinach cultivated in soil and hydroponic media

Science.gov (United States)

Introduction: Internalization of E. coli O157:H7 into spinach plants through root uptake is a potential route of contamination. Previous studies that have investigated uptake of E. coli O157:H7 into leafy greens have expressed green fluorescent protein (gfp) from a plasmid, possibly limiting detecti...

Determination of terbium in phosphate rock by Tb{sup 3+}-selective fluorimetric optode based on dansyl derivative as a neutral fluorogenic ionophore

Energy Technology Data Exchange (ETDEWEB)

Hosseini, Morteza, E-mail: smhosseini@khayam.ut.ac.ir [Department of Chemistry, Islamic Azad University, Savadkooh Branch, Savadkooh (Iran, Islamic Republic of); Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Veismohammadi, Bahareh [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Faridbod, Farnoush [Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Abkenar, Shiva Dehghan [Department of Chemistry, Islamic Azad University, Savadkooh Branch, Savadkooh (Iran, Islamic Republic of); Norouzi, Parviz [Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

2010-04-07

For the first time a highly sensitive and selective fluorimetric optode membrane was prepared for determination of trace amounts of Tb(III) ions in phosphate rock samples. The Tb(III) sensing system was constructed by incorporating 5-(dimethylamino)-N'-(2-hydroxy-1-naphthoyl) naphthalene-1-sulfonohydrazine (L) as a neutral Tb(III)-selective fluoroionophore, in the plasticized PVC membrane containing sodium tetraphenyl borate as a liphophilic anionic additive. The response of the optode is based on the strong fluorescence quenching of L by Tb{sup 3+} ions. At a pH value of 5.0, the optode displays a wide concentration range of 1.0 x 10{sup -7} to 1.0 x 10{sup -2} M, with a relatively fast response time of less than 45 s. In addition, to high stability and reproducibility, the sensor shows a unique selectivity towards Tb{sup 3+} ion with respect to common cations. The optode was applied successfully to the trace determination of terbium ion in binary mixture and water samples and the determination of Tb{sup 3+} in phosphate rock samples.

Escherichia coli O157:H7- patógeno alimentar emergente / Escherichia coli O157:H7 - emerging food pathogen

Directory of Open Access Journals (Sweden)

Cheila Minéia Daniel de Paula

2014-11-01

Full Text Available Segundo a Organização Mundial da Saúde, cerca de 2,2 milhões de pessoas morrem anualmente em função de doenças hídricas ou alimentares, a maioria dos quais são crianças. Estas doenças são causadas por patógenos já conhecidos, emergentes ou reemergentes, principalmente bactérias. A globalização tem contribuído na disseminação de patógenos de origem alimentar, aumentando o desafio relacionado à identificação da origem desses agentes e à elaboração de regulamentação e fiscalização adequadas. O cenário das Doenças Transmitidas por Alimentos (DTA muda constantemente e a prevalência de determinada doença varia de época para época, assim como os agentes etiológicos destas. Dentre os principais patógenos emergentes em nível mundial, E. coli O157:H7 tem ganhado grande destaque nos últimos 20 anos, devido à severidade de seus surtos. Até pouco tempo, o Brasil era considerado livre desse patógeno, porém a bibliografia científica e registros epidemiológicos demonstram o contrário. Em vista disso, o presente artigo objetiva realizar uma revisão integrativa da literatura, enfocando as características, os métodos de isolamento e detecção e os dados epidemiológicos da E. coli O157:H7 no Brasil e no mundo. =============================================== According to the World Health Organization, about 2.2 million people, most of whom are children, die each year due to water and foodborne illnesses. These illnesses are caused by known, emerging, or reemerging pathogens, mainly bacteria. Globalization has contributed to the spread of foodborne pathogens, increasing the challenge of identifying the origin of these agents and of developing appropriate regulation and monitoring. The scenario of Foodborne Illnesses (FI constantly changes and the prevalence of a particular illnesses as well as its etiological agents, vary from season to season. Among the major emerging pathogens at a global level, E. coli O157:H7

Escherichia coli O157:H7 bacteriophage 241 isolated from an industrial cucumber fermentation at high acidity and salinity

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Zhongjing eLu

2015-02-01

Full Text Available A novel phage, 241, specific for Escherichia coli O157:H7 was isolated from an industrial cucumber fermentation where both acidity (pH  3.7 and salinity ( 5% NaCl were high. The phage belongs to the Myoviridae family. Its latent period was 15 min and average burst size was 53 phage particles per infected cell. The phage was able to lyse 48 E. coli O157:H7 strains, but none of the 18 non-O157 strains (including E. coli O104:H7 or the 2 O antigen-negative mutants of O157:H7 strain, 43895per (also lacking H7 antigen and F12 (still expressing H7 antigen. However, the phage was able to lyse a per-complemented strain (43895perComp which expresses O157 antigen. These results indicated that phage 241 is specific for O157 antigen, and E. coli strains lacking O157 antigen were resistant to the phage infection, regardless of the presence or absence of H7 antigen. SDS-PAGE profile revealed at least 13 structural proteins of the phage. The phage DNA was resistant to many commonly used restriction endonucleases, suggesting the presence of modified nucleotides in the phage genome. At the multiplicity of infection of 10, 3 or 0.3, the phage caused a rapid cell lysis within 1 or 2 h, resulting in 3.5- or 4.5-log-unit reduction in cell concentration. The high lytic activity, specificity and tolerance to low pH and high salinity make phage 241 a potentially ideal biocontrol agent of E. coli O157:H7 in various foods. To our knowledge, this is the first report on E. coli O157:H7 phage isolated from high acidity and salinity environment.

Bovine milk fat globule membrane affects virulence expression in Escherichia coli O157:H7.

Science.gov (United States)

Tellez, A; Corredig, M; Guri, A; Zanabria, R; Griffiths, M W; Delcenserie, V

2012-11-01

The aim of this study was to examine the effect of the bovine milk fat globule membrane (MFGM) on the virulence of Escherichia coli O157:H7. The MFGM was extracted from raw or heat-treated milk, resulting in 2 preparations differing in protein composition. Both heated and raw MFGM exerted an inhibitory effect on Shiga toxin gene expression by E. coli O157:H7 (ratios of -7.69 and -5.96, respectively). Interestingly, the effect was stronger with heated MFGM, with a larger decrease in expression of the virulence gene fliC (ratio of -9.43). The difference in effect observed between heated and raw MFGM could be explained by the difference in protein composition between the 2 preparations. These results show, for the first time, a specific effect of MFGM on expressionof Shiga toxin genes as well as genes involved in the motility of E. coli O157:H7. This may offer a new approach to mitigate the adverse health effects caused by E. coli O157:H7 infections. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Prevalence and antibiogram of Escherichia coli O157 isolated from ...

African Journals Online (AJOL)

E. coli O157 from bovine carcass swabs and cecal contents were 9.3% and 7.3%, respectively. ..... Frequent use of tetracycline to treat animal dis- eases in ... Project entitled “Pneumonia, diarrhea and mastitis in food animals”. References.

Body protective compound-157 enhances alkali-burn wound healing in vivo and promotes proliferation, migration, and angiogenesis in vitro

Science.gov (United States)

Huang, Tonglie; Zhang, Kuo; Sun, Lijuan; Xue, Xiaochang; Zhang, Cun; Shu, Zhen; Mu, Nan; Gu, Jintao; Zhang, Wangqian; Wang, Yukun; Zhang, Yingqi; Zhang, Wei

2015-01-01

Chemical burns take up a high proportion of burns admissions and can penetrate deep into tissues. Various reagents have been applied in the treatment of skin chemical burns; however, no optimal reagent for skin chemical burns currently exists. The present study investigated the effect of topical body protective compound (BPC)-157 treatment on skin wound healing, using an alkali burn rat model. Topical treatment with BPC-157 was shown to accelerate wound closure following an alkali burn. Histological examination of skin sections with hematoxylin–eosin and Masson staining showed better granulation tissue formation, reepithelialization, dermal remodeling, and a higher extent of collagen deposition when compared to the model control group on the 18th day postwounding. BPC-157 could promote vascular endothelial growth factor expression in wounded skin tissues. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and cell cycle analysis demonstrated that BPC-157 enhanced the proliferation of human umbilical vein endothelial cells (HUVECs). Transwell assay and wound healing assay showed that BPC-157 significantly promoted migration of HUVECs. We also observed that BPC-157 upregulated the expression of VEGF-a and accelerated vascular tube formation in vitro. Moreover, further studies suggested that BPC-157 regulated the phosphorylation level of extracellular signal-regulated kinases 1 and 2 (ERK1/2) as well as its downstream targets, including c-Fos, c-Jun, and Egr-1, which are key molecules involved in cell growth, migration, and angiogenesis. Altogether, our results indicated that BPC-157 treatment may accelerate wound healing in a model of alkali burn-induced skin injury. The therapeutic mechanism may be associated with accelerated granulation tissue formation, reepithelialization, dermal remodeling, and collagen deposition through ERK1/2 signaling pathway. PMID:25995620

Identification and Prevalence of Escherichia coli and Escherichia coli O157: H7 in Foods

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Ancuta Mihaela Rotar

2013-11-01

Full Text Available The objective of this study is to investigate the incidence of Escherichia coli in animal and non-animal foods, and mainly the incidence of the serotype O157: H7 producing verotoxin. The presence of common Escherichia coli and Escherichia coli O157: H7 in various foods (of animal and non animal origin was performed in Transylvania area. We analyzed a total of one hundred forty-one samples of minced meat, one hundred twenty-six samples of meat , twenty six samples of meat products, five samples of alcoholic beverages, three samples of seafood, one hundred samples of cheese from pasteurized milk, seventeen samples of butter, four samples of vegetables and one sample of milk powder, using the standard cultural method and Vidas Eco method for E. coli O157: H7 strains. E. coli was identified in 50 samples of minced meat, 55 samples of meat prepared, 4 samples of meat products, 2 samples of alcoholic beverages, 25 samples of cheese from pasteurized milk, 6 samples of butter and 1 sample of vegetables. In this study were not been identified any foods contaminated with the E. coli O157: H7 serotype. The results of this reasearch have demostrated that E. coli wich represents a hygienic indicator of recent food contamination, can be destroyed with heat treatment and hygienic handling of foods. Our country over the years has been among the few countries where the incidence of the E. coli O157: H7 serotype has been minimal.

Screening of the novel colicinogenic gram-negative rods against pathogenic Escherichia coli O157:H7

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H Mushtaq

2015-01-01

Full Text Available Purpose: Escherichia coli (E. coli O157:H7 is gram-negative enteric pathogen producing different types of Shiga toxin. This bacterium is the most corporate cause of haemorrhagic colitis in human. Administration of antibiotics (particularly sulfa drugs against this pathogen is a debatable topic as this may increase the risk of uremic syndrome; especially in children and aged people. Around the world, microbiologists are in search of alternative therapeutic methods specially probiotics against this pathogen. In the present study, we have focused on the investigation of alternate bio-therapeutics (probiotics for the treatment of patients infected with E. coli O157:H7. This study is based on the identification of colicin-producing gram-negative bacteria (particularly enterobacteriaceae which can competently exclude E. coli O157:H7 from the gut of the infected individual. Materials and Methods: Hundred samples from human, animal faeces and septic tank water were analysed for nonpathogenic gram-negative rods (GNRs. Results: Out of these samples, 175 isolates of GNRs were checked for their activity against E. coli O157:H7. Only 47 isolates inhibited the growth of E. coli O157:H7, among which majority were identified as E. coli. These E. coli strains were found to be the efficient producers of colicin. Some of the closely related species i. e., Citrobacter sp, Pantoea sp. and Kluyvera sp. also showed considerable colicinogenic activity. Moreover, colicinogenic species were found to be nonhaemolytic, tolerant to acidic environment (pH 3 and sensitive to commonly used antibiotics. Conclusion: Nonhaemolytic, acid tolerant and sensitive to antibiotics suggests the possible use of these circulating endothelial cells (CEC as inexpensive and inoffensive therapeutic agent (probiotics in E. coli O157:H7 infections.

Most probable number methodology for quantifying dilute concentrations and fluxes of Escherichia coli O157:H7 in surface waters.

Science.gov (United States)

Jenkins, M B; Endale, D M; Fisher, D S; Gay, P A

2009-02-01

To better understand the transport and enumeration of dilute densities of Escherichia coli O157:H7 in agricultural watersheds, we developed a culture-based, five tube-multiple dilution most probable number (MPN) method. The MPN method combined a filtration technique for large volumes of surface water with standard selective media, biochemical and immunological tests, and a TaqMan confirmation step. This method determined E. coli O157:H7 concentrations as low as 0.1 MPN per litre, with a 95% confidence level of 0.01-0.7 MPN per litre. Escherichia coli O157:H7 densities ranged from not detectable to 9 MPN per litre for pond inflow, from not detectable to 0.9 MPN per litre for pond outflow and from not detectable to 8.3 MPN per litre for within pond. The MPN methodology was extended to mass flux determinations. Fluxes of E. coli O157:H7 ranged from 10(4) MPN per hour. This culture-based method can detect small numbers of viable/culturable E. coli O157:H7 in surface waters of watersheds containing animal agriculture and wildlife. This MPN method will improve our understanding of the transport and fate of E. coli O157:H7 in agricultural watersheds, and can be the basis of collections of environmental E. coli O157:H7.

Terbium to Quantum Dot FRET Bioconjugates for Clinical Diagnostics: Influence of Human Plasma on Optical and Assembly Properties

Directory of Open Access Journals (Sweden)

Niko Hildebrandt

2011-10-01

Full Text Available Förster resonance energy transfer (FRET from luminescent terbium complexes (LTC as donors to semiconductor quantum dots (QDs as acceptors allows extraordinary large FRET efficiencies due to the long Förster distances afforded. Moreover, time-gated detection permits an efficient suppression of autofluorescent background leading to sub-picomolar detection limits even within multiplexed detection formats. These characteristics make FRET-systems with LTC and QDs excellent candidates for clinical diagnostics. So far, such proofs of principle for highly sensitive multiplexed biosensing have only been performed under optimized buffer conditions and interactions between real-life clinical media such as human serum or plasma and LTC-QD-FRET-systems have not yet been taken into account. Here we present an extensive spectroscopic analysis of absorption, excitation and emission spectra along with the luminescence decay times of both the single components as well as the assembled FRET-systems in TRIS-buffer, TRIS-buffer with 2% bovine serum albumin, and fresh human plasma. Moreover, we evaluated homogeneous LTC-QD FRET assays in QD conjugates assembled with either the well-known, specific biotin-streptavidin biological interaction or, alternatively, the metal-affinity coordination of histidine to zinc. In the case of conjugates assembled with biotin-streptavidin no significant interference with the optical and binding properties occurs whereas the histidine-zinc system appears to be affected by human plasma.

Synergistic interaction in dual-species biofilms formation by Escherichia coli O157:H7 and Ralstonia spp

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Introduction: Ralstonia spp., a heterotrophic bacterium that are isolated from produce processing environments as part of the native microflora, have strong potentials for formaing biofilms on various surfaces. When co-cultured, Escherichia coli O157:H7 (EcO157) and Ralstonia spp. displayed a synerg...

Determination of terbium in phosphate rock by Tb3+-selective fluorimetric optode based on dansyl derivative as a neutral fluorogenic ionophore.

Science.gov (United States)

Hosseini, Morteza; Ganjali, Mohammad Reza; Veismohammadi, Bahareh; Faridbod, Farnoush; Abkenar, Shiva Dehghan; Norouzi, Parviz

2010-04-07

For the first time a highly sensitive and selective fluorimetric optode membrane was prepared for determination of trace amounts of Tb(III) ions in phosphate rock samples. The Tb(III) sensing system was constructed by incorporating 5-(dimethylamino)-N'-(2-hydroxy-1-naphthoyl) naphthalene-1-sulfonohydrazine (L) as a neutral Tb(III)-selective fluoroionophore, in the plasticized PVC membrane containing sodium tetraphenyl borate as a liphophilic anionic additive. The response of the optode is based on the strong fluorescence quenching of L by Tb(3+) ions. At a pH value of 5.0, the optode displays a wide concentration range of 1.0 x 10(-7) to 1.0 x 10(-2)M, with a relatively fast response time of less than 45 s. In addition, to high stability and reproducibility, the sensor shows a unique selectivity towards Tb(3+) ion with respect to common cations. The optode was applied successfully to the trace determination of terbium ion in binary mixture and water samples and the determination of Tb(3+) in phosphate rock samples. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

Preparation of transparent sol-gel films containing europium, terbium, and ytterbium cations from 4-(3'-triethoxysilylpropylimino)pent-2-en-2-ol

International Nuclear Information System (INIS)

Semenov, V.V.; Cherepennikova, N.F.; Kuznetsova, O.V.; Melenskova, N.V.; Bushuk, B.A.; Bushuk, S.B.; Kal'vinkovskaya, Yu.A.; Duglas, V.E.

2007-01-01

A reaction of 3-aminopropyl(triethoxy)silane with acetylacetone gave a mixture of two isomeric carbon-functionalized organosilicon compounds capable of complexation and sol-gel polymerization. These were 4-(3'-triethoxysilylpropylimino)pent-2-en-2-ol (EtO) 3 Si-CH 2 CH 2 CH 2 -N=C(Me)CH=C(Me)OH (Ia, 83%) and 4-(3'-triethoxysilylpropylamino)pent-3-en-2-one (EtO) 3 Si-CH 2 CH 2 CH 2 -NH-C(Me)=CH-C(O)Me (Ib, 17%). With acetylacetone trimethylsilyl ether instead of acetylacetone itself, compound Ia and silylated derivatives (Me 3 SiO) n (EtO) 3-n Si-CH 2 CH 2 CH 2 -N=C(Me)CH=C(Me)OH were obtained as admixture in 84 and 16% yields, respectively. Reactions of ligands Ia and Ib with europium and terbium propan-2-olates afforded the corresponding complexes. Formulations of lanthanide complexes, oligodimethylsiloxanediols, and 3-aminopropyl(triethoxy)silane were used to prepare transparent sol-gel films. The photoluminescence spectra of the films show narrow bands due to Eu 3+ or Tb 3+ emission. Emission from the organosilicon matrix appears as a broad band at 430 to 435 nm [ru

Does enterohemorrhagic Escherichia coli O157:H7 enter the viable but nonculturable state in salted salmon roe?

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Makino, S I; Kii, T; Asakura, H; Shirahata, T; Ikeda, T; Takeshi, K; Itoh, K

2000-12-01

An outbreak caused by salted salmon roe contaminated with enterohemorrhagic Escherichia coli O157 occurred in Japan in 1998. Since about 0.75 to 1.5 viable cells were estimated to cause infection, we presumed that O157 might enter the viable but nonculturable (VNC) state in salted salmon roe and consequently that viable cell numbers might be underestimated. Although patient-originating O157 cells could not grow on agar plates after 72 h of incubation in 13% NaCl, they were resuscitated in yeast extract broth, and more than 90% of the cells were shown to be viable by fluorescent staining, suggesting that almost all of them could enter the VNC state in NaCl water. Roe-originating O157 was resistant to NaCl because it could grow on agar after 72 h of incubation in NaCl water, but about 20% of cells appeared to enter the VNC state. Therefore, germfree mice were infected with O157 to examine the resuscitation of cells in the VNC state and the retention of pathogenicity. O157 that originated in roe, but not patients, killed mice and was isolated from the intestine. However, these isolates had become sensitive to NaCl. O157 cells of roe origin incubated in normal media also killed mice and were isolated from the intestine, but they also became transiently NaCl sensitive. We therefore propose that bacterial cells might enter the VNC state under conditions of stress, such as those encountered in vivo or in high salt concentrations, and then revive when those conditions have eased. If so, the VNC state in food is potentially dangerous from a public health viewpoint and may have to be considered at the time of food inspection. Finally, the establishment of a simple recovery system for VNC cells should be established.

Synergistic effect of enterocin AS-48 in combination with outer membrane permeabilizing treatments against Escherichia coli O157:H7.

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Ananou, S; Gálvez, A; Martínez-Bueno, M; Maqueda, M; Valdivia, E

2005-01-01

To determine the effects of outer membrane (OM) permeabilizing agents on the antimicrobial activity of enterocin AS-48 against Escherichia coli O157:H7 CECT 4783 strain in buffer and apple juice. We determined the influence of pH, EDTA, sodium tripolyphosphate (STPP) and heat on E. coli O157:H7 CECT 4783 sensitivity to enterocin AS-48 in buffer and in apple juice. Enterocin AS-48 was not active against intact cells of E. coli O157:H7 CECT 4783 at neutral pH. However, cells sublethally injured by OM permeabilizing agents (EDTA, STPP, pH 5, pH 8.6 and heat) became sensitive to AS-48, decreasing the amount of bacteriocin required for inhibition of E. coli O157:H7 CECT 4783. The results presented indicate that enterocin AS-48 could potentially be applied with a considerably wider range of protective agents, such as OM permeabilizing agents, with increased efficacy in inhibiting E. coli O157:H7. Results from this study support the potential use of enterocin AS-48 to control E. coli O157:H7 in combination with other hurdles.

Curli fimbriae are conditionally required in Escherichia coli O157:H7 for initial attachment and biofilm formation.

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Carter, Michelle Qiu; Louie, Jacqueline W; Feng, Doris; Zhong, Wayne; Brandl, Maria T

2016-08-01

Several species of enteric pathogens produce curli fimbriae, which may affect their interaction with surfaces and other microbes in nonhost environments. Here we used two Escherichia coli O157:H7 outbreak strains with distinct genotypes to understand the role of curli in surface attachment and biofilm formation in several systems relevant to fresh produce production and processing. Curli significantly enhanced the initial attachment of E. coli O157:H7 to spinach leaves and stainless steel surfaces by 5-fold. Curli was also required for E. coli O157:H7 biofilm formation on stainless steel and enhanced biofilm production on glass by 19-27 fold in LB no-salt broth. However, this contribution was not observed when cells were grown in sterile spinach lysates. Furthermore, both strains of E. coli O157:H7 produced minimal biofilms on polypropylene in LB no-salt broth but considerable amounts in spinach lysates. Under the latter conditions, curli appeared to slightly increase biofilm production. Importantly, curli played an essential role in the formation of mixed biofilm by E. coli O157:H7 and plant-associated microorganisms in spinach leaf washes, as revealed by confocal microscopy. Little or no E. coli O157:H7 biofilms were detected at 4 °C, supporting the importance of temperature control in postharvest and produce processing environments. Published by Elsevier Ltd.

Patient survival and tumor characteristics associated with CHEK2:p.I157T - findings from the Breast Cancer Association Consortium

DEFF Research Database (Denmark)

Muranen, Taru A; Blomqvist, Carl; Dörk, Thilo

2016-01-01

BACKGROUND: P.I157T is a CHEK2 missense mutation associated with a modest increase in breast cancer risk. Previously, another CHEK2 mutation, the protein truncating c.1100delC has been associated with poor prognosis of breast cancer patients. Here, we have investigated patient survival...... and characteristics of breast tumors of germ line p.I157T carriers. METHODS: We included in the analyses 26,801 European female breast cancer patients from 15 studies participating in the Breast Cancer Association Consortium. We analyzed the association between p.I157T and the clinico-pathological breast cancer...... characteristics by comparing the p.I157T carrier tumors to non-carrier and c.1100delC carrier tumors. Similarly, we investigated the p.I157T associated risk of early death, breast cancer-associated death, distant metastasis, locoregional relapse and second breast cancer using Cox proportional hazards models...

Inner-sphere and outer-sphere complexes of yttrium(III), lanthanum (III), neodymium(III), terbium(III) and thulium(III) with halide ions in N,N-dimethylformamide

International Nuclear Information System (INIS)

Takahashi, Ryouta; Ishiguro, Shin-ichi

1991-01-01

The formation of chloro, bromo and iodo complexes of yttrium(III), and bromo and iodo complexes of lanthanum(III), neodymium(III), terbium(III) and thulium(III) has been studied by precise titration calorimetry in N,N-dimethylformamide (DMF) at 25 o C. The formation of [YCl] 2+ , [YCl 2 ] + , [YCl 3 ] and [YCl 4 ] - , and [MBr] 2+ and [MBr 2 ] + (M = Y, La, Nd, Tb, Tm) was revealed, and their formation constants, enthalpies and entropies were determined. It is found that the formation enthalpies change in the sequence ΔH o (Cl) > ΔH o (l), which is unusual for hard metal (III) ions. This implies that, unlike the chloride ion, the bromide ion forms outer-sphere complexes with the lanthanide(III) and yttrium(III) ions in DMF. Evidence for either an inner- or outer-sphere complex was obtained from 89 Y NMR spectra for Y(ClO 4 ) 3 , YCl 3 and YBr 3 DMF solutions at room temperature. (author)

Proliferation of Escherichia coli O157:H7 in Soil-Substitute and Hydroponic Microgreen Production Systems.

Science.gov (United States)

Xiao, Zhenlei; Bauchan, Gary; Nichols-Russell, Lydia; Luo, Yaguang; Wang, Qin; Nou, Xiangwu

2015-10-01

Radish (Raphanus sativus var. longipinnatus) microgreens were produced from seeds inoculated with Escherichia coli O157:H7 by using peat moss-based soil-substitute and hydroponic production systems. E. coli populations on the edible and inedible parts of harvested microgreen plants (7 days postseeding) and in growth medium were examined. E. coli O157:H7 was shown to survive and proliferate significantly during microgreen growth in both production systems, with a higher level in the hydroponic production system. At the initial seed inoculation level of 3.7 log CFU/g, E. coli O157:H7 populations on the edible part of microgreen plants reached 2.3 and 2.1 log CFU/g (overhead irrigation and bottom irrigation, respectively) for microgreens from the soil-substitute production system and reached 5.7 log CFU/g for those hydroponically grown. At a higher initial inoculation of 5.6 log CFU/g seeds, the corresponding E. coli O157:H7 populations on the edible parts of microgreens grown in these production systems were 3.4, 3.6, and 5.3 log CFU/g, respectively. Examination of the spatial distribution of bacterial cells on different parts of microgreen plants showed that contaminated seeds led to systematic contamination of whole plants, including both edible and inedible parts, and seed coats remained the focal point of E. coli O157:H7 survival and growth throughout the period of microgreen production.

Aislamiento, caracterización y subtipificación de cepas de Escherichia coli O157:H7 a partir de productos cárnicos y leche Isolation, characterization and typing of Escherichia coli O157:H7 strains from beef products and milk

Directory of Open Access Journals (Sweden)

M. L. Roldán

2007-06-01

Full Text Available Escherichia coli productor de toxina Shiga (Stx (STEC O157:H7 es un patógeno asociado a enfermedades transmitidas por alimentos, fundamentalmente de origen animal. Se investigó la presencia de E. coli O157 en 250 muestras de carne picada y hamburguesas obtenidas de comercios de las ciudades de Santa Fe y Santo Tomé (Pcia. de Santa Fe y en 150 muestras de leche provenientes de tanques de enfriado de tambos de la región, utilizando enriquecimiento selectivo y separación inmunomagnética. A partir de 3 muestras de carne (1,2% se aislaron cepas E. coli O157:H7 stx2, eae, y ehxA positivas, que pudieron ser diferenciadas mediante electroforesis de campo pulsado, fagotipificación y genotipificación de stx. No se aislaron cepas STEC O157:H7 a partir de las muestras de leche. Estos hallazgos confirman la participación de los alimentos de origen animal en la epidemiología de las enfermedades producidas por E. coli O157:H7.Shiga toxin (Stx-producing Escherichia coli (STEC is an emergent pathogen associated with foodborne diseases, especially foodstuffs of animal origin. A total of 250 beef samples (ground beef and hamburgers obtained from retail outlets in Santa Fe and Santo Tomé cities, and 150 milk samples from bulk tank milk from dairy barns of the region were analyzed by selective enrichment and immunomagnetic separation. Escherichia coli O157:H7 stx2, eae and ehxA positive strains were isolated from three (1.2% beef samples. The strains could be differentiated by pulsed-field gel electrophoresis, phagetyping and genotyping of stx. The milk samples were negative for STEC O157. These findings confirm the role of food of animal origin in the epidemiology of E. coli O157:H7 - associated diseases.

D10 value determination for Escherichia coli O157:H7 in different cultivations

International Nuclear Information System (INIS)

Oliveira, Sergio Eduardo M. de; Pires, Luis Fernando G.; Vital, Helio de C.

2002-01-01

Escherichia coli serum type O157:H7 is a highly pathogenic bacterium. Inside the human body, that microorganism causes a disease that leads to bloody diarrhea, stoppage of kidney functions and clots in the brain. That type of infection has been related to the consumption of different varieties of foods, mainly meat and other products of animal origin. Irradiation is an efficient method for elimination of pathogenic and spoiling microorganisms in foods. Thus, this work investigates the use of gamma irradiation for elimination of Escherichia coli O157:H7. For that purpose, inoculated samples in trypticase soy broth and saline solution 0,85% media were exposed to several gamma radiation doses. Counting the number of surviving bacteria yielded the following D 10 values for Escherichia coli O157:H7: 98±7 Gy, in trypticase soy broth and 49±4 Gy in saline solution 0,85% medium. (author)

[Construction and characterization of enterohemorrhagic Escherichia coli O157:H7 ppk- deleted strain].

Science.gov (United States)

Han, Peng; Sun, Qi; Zhao, Suhui; Zhang, Qiwei; Wan, Chengsong

2014-06-01

To construct enterohemorrhagic Escherichia coli (EHEC) O157: H7 ppk gene deletion strains and study its biological characteristics. The gene fragment of kanamycin resistance was amplified using a pair of homologous arm primers whose 5' and 3' ends were homologous with ppk gene and kanamycin resistance gene, respectively. EHEC O157: H7 EDL933w competent strains were prepared and transformed via electroporation with the amplification products. The ppk gene was replaced by kanamycin resistance gene using pKD46-mediated Red recombination system. The recombinant strain was confirmed by PCR and sequencing, and its morphology, growth ability and adhesion were assessed using Gram staining, OD600 value and Giemsa staining. We established a ppk-deleted EHEC O157:H7 EDL933w strain with kanamycin resistance and compared the biological characteristics of the wild-type and mutant strains, which may facilitate further study of the regulatory mechanism of ppk gene.

Ethylenediaminetetraacetate and lysozyme improves antimicrobial activities of ovotransferrin against Escherichia coli O157:H7.

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Ko, K Y; Mendoncam, A F; Ismail, H; Ahn, D U

2009-02-01

The aim of this study was to evaluate the effect of EDTA, lysozyme, or the combination of EDTA and lysozyme on the antibacterial activity of ovotransferrin against Escherichia coli O157:H7. Ovotransferrin solutions (20 mg/mL) containing 100 mM NaHCO3 (OS) with added EDTA (2.0 or 2.5 mg/mL), lysozyme (1.0, 1.5, or 2.0 mg/mL), or both were prepared. The antibacterial activities of OS, OSE (OS+EDTA), or OSL (OS+lysozyme) against E. coli O157:H7 in model systems were investigated by turbidity and viability tests. In addition, OSE, OSL, or OSEL (OS+EDTA+lysozyme) was applied to irradiated pork chops and commercial hams to determine whether the solutions had antibacterial activity on meat products. The effect of the initial cell population on the antibacterial activity of OSE, OSL, and OSEL was determined. Ethylenediaminetetraacetate at 2 mg/mL plus OS induced a reduction of approximately 3 to 4 log in viable E. coli O157:H7 cells in brain heart infusion broth media, and 1 mg/mL of lysozyme plus OS resulted in a reduction of approximately 0.5 to 1.0 log during a 36-h incubation at 35 degrees C. However, neither OSE nor OSEL showed a significant antibacterial effect on pork chops and hams during storage at 10 degrees C. The initial cell number in media did not affect the antibacterial activity of OSE or OSEL against E. coli O157:H7. This study demonstrates that combinations of ovotransferrin, NaHCO3, and EDTA have the potential to control E. coli O157:H7.

Salt at concentrations relevant to meat processing enhances Shiga toxin 2 production in Escherichia coli O157:H7.

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Harris, Shaun M; Yue, Wan-Fu; Olsen, Sarena A; Hu, Jia; Means, Warrie J; McCormick, Richard J; Du, Min; Zhu, Mei-Jun

2012-10-15

Escherichia coli (E. coli) O157:H7 remains a major food safety concern associated with meat, especially beef products. Shiga toxins (Stx) are key virulence factors produced by E. coli O157:H7 that are responsible for hemorrhagic colitis and Hemolytic Uremic Syndrome. Stx are heat stable and can be absorbed after oral ingestion. Despite the extensive study of E. coli O157:H7 survival during meat processing, little attention is paid to the production of Stx during meat processing. The objective of this study was to elucidate the effect of salt, an essential additive to processed meat, at concentrations relevant to meat processing (0%, 1%, 2%, 3%, W/V) on Stx2 production and Stx2 prophage induction by E. coli O157:H7 strains. For both E. coli O157:H7 86-24 and EDL933 strains, including 2% salt in LB broth decreased (Pmeat processing enhances Stx production, a process linked to bacterial stress response and lambdoid prophage induction. Published by Elsevier B.V.

E. coli O157 on Scottish cattle farms: Evidence of local spread and persistence using repeat cross-sectional data

Science.gov (United States)

2014-01-01

Background Escherichia coli (E. coli) O157 is a virulent zoonotic strain of enterohaemorrhagic E. coli. In Scotland (1998-2008) the annual reported rate of human infection is 4.4 per 100,000 population which is consistently higher than other regions of the UK and abroad. Cattle are the primary reservoir. Thus understanding infection dynamics in cattle is paramount to reducing human infections. A large database was created for farms sampled in two cross-sectional surveys carried out in Scotland (1998 - 2004). A statistical model was generated to identify risk factors for the presence of E. coli O157 on farms. Specific hypotheses were tested regarding the presence of E. coli O157 on local farms and the farms previous status. Pulsed-field gel electrophoresis (PFGE) profiles were further examined to ascertain whether local spread or persistence of strains could be inferred. Results The presence of an E. coli O157 positive local farm (average distance: 5.96km) in the Highlands, North East and South West, farm size and the number of cattle moved onto the farm 8 weeks prior to sampling were significant risk factors for the presence of E. coli O157 on farms. Previous status of a farm was not a significant predictor of current status (p = 0.398). Farms within the same sampling cluster were significantly more likely to be the same PFGE type (p Scottish E. coli O157 paves the way for future research into the mechanisms of transmission which should help with the design of control measures to reduce E. coli O157 from livestock-related sources. PMID:24766709

Detection of viable Escherichia coli O157:H7 in ground beef by propidium monoazide real-time PCR.

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Liu, Yarui; Mustapha, Azlin

2014-01-17

Escherichia coli O157:H7 associated with food has caused many serious public health problems in recent years. However, only viable cells of this pathogen can cause infections, and false-positive detection caused by dead cells can lead to unnecessary product recalls. The objective of this study was to develop and optimize a method that combines propidium monoazide (PMA) staining with real-time PCR to detect only viable cells of E. coli O157:H7 in ground beef. PMA is a DNA intercalating dye that can penetrate compromised membranes of dead cells and bind to cellular DNA, preventing its amplification via a subsequent PCR. Three strains of E. coli O157:H7 (505B, G5310 and C7927) at concentrations of 10(0) to 10(8)CFU/mL were used as live cells. Dead cells were obtained by heating cell suspensions at 85°C for 15 min. Suspensions were treated with PMA and the optimized assay was applied to artificially contaminated ground beef with two different fat contents (10% and 27%). DNA was extracted and amplified by TaqMan® real-time PCR assay targeting the uidA gene for detection of E. coli O157:H7. Plasmid pUC19 was added as an internal amplification control (IAC). A treatment of 25 μM PMA with a 10-min light exposure on ice was sufficient to eliminate DNA from 10(8) dead E. coli O157:H7 cells/mL. The optimized assay could detect as low as 10(2) CFU/mL viable E. coli O157:H7 in pure culture and 10(5) CFU/g in ground beef, in the presence of 10(6)/mL or g of dead cells. With an 8-h enrichment, 1 CFU/g viable E. coli O157:H7 in ground beef was detectable without interference from 10(6) dead cells/g. In conclusion, the PMA real-time PCR could effectively detect viable E. coli O157:H7 without being compromised by dead cells. Copyright © 2013 Elsevier B.V. All rights reserved.

Regional variation in the prevalence of E. coli O157 in cattle: a meta-analysis and meta-regression.

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Islam, Md Zohorul; Musekiwa, Alfred; Islam, Kamrul; Ahmed, Shahana; Chowdhury, Sharmin; Ahad, Abdul; Biswas, Paritosh Kumar

2014-01-01

Escherichia coli O157 (EcO157) infection has been recognized as an important global public health concern. But information on the prevalence of EcO157 in cattle at the global and at the wider geographical levels is limited, if not absent. This is the first meta-analysis to investigate the point prevalence of EcO157 in cattle at the global level and to explore the factors contributing to variation in prevalence estimates. Seven electronic databases- CAB Abstracts, PubMed, Biosis Citation Index, Medline, Web of Knowledge, Scirus and Scopus were searched for relevant publications from 1980 to 2012. A random effect meta-analysis model was used to produce the pooled estimates. The potential sources of between study heterogeneity were identified using meta-regression. A total of 140 studies consisting 220,427 cattle were included in the meta-analysis. The prevalence estimate of EcO157 in cattle at the global level was 5.68% (95% CI, 5.16-6.20). The random effects pooled prevalence estimates in Africa, Northern America, Oceania, Europe, Asia and Latin America-Caribbean were 31.20% (95% CI, 12.35-50.04), 7.35% (95% CI, 6.44-8.26), 6.85% (95% CI, 2.41-11.29), 5.15% (95% CI, 4.21-6.09), 4.69% (95% CI, 3.05-6.33) and 1.65% (95% CI, 0.77-2.53), respectively. Between studies heterogeneity was evidenced in most regions. World region (p<0.001), type of cattle (p<0.001) and to some extent, specimens (p = 0.074) as well as method of pre-enrichment (p = 0.110), were identified as factors for variation in the prevalence estimates of EcO157 in cattle. The prevalence of the organism seems to be higher in the African and Northern American regions. The important factors that might have influence in the estimates of EcO157 are type of cattle and kind of screening specimen. Their roles need to be determined and they should be properly handled in any survey to estimate the true prevalence of EcO157.

Growth kinetics of Escherichia coli O157:H7 on the epicarp of fresh vegetables and fruits

Directory of Open Access Journals (Sweden)

Mariel Gullian-Klanian

Full Text Available ABSTRACT Despite the increasing reports on the incidence of fresh vegetables and fruits as a possible vehicle for human pathogens, there is currently limited knowledge on the growth potential of Escherichia coli O157:H7 on different plant substrates. This study analyzed the selective adhesion and growth of E. coli O157:H7 on chili habanero (Capsicum chinense L., cucumber (Cucumis sativus, radish (Raphanus sativus, tomato (Lycopersicon esculentum, beet (Beta vulgaris subsp. vulgaris, and onion (Allium cepa L. under laboratory conditions. The Gompertz parameters were used to determine the growth kinetics. Scanning electron microscopy was used to visualize the adhesion of E. coli O157:H7 on the epicarp of the samples. Predictive models were constructed to compare the growth of E. coli O157:H7 on the samples with different intrinsic factors and to demonstrate the low selectivity of the pathogen. No significant difference was observed in the lag-phase duration (LPD, generation time (GT, and exponential growth rate (EGR of the pathogen adhered to the samples. The interaction between the microorganism and the substrate was less supportive to the growth of E. coli O157:H7 for onion, whereas for tomato and cucumber, the time for the microorganism to attain the maximum growth rate (M was significantly longer than that recorded for other samples.

Sorbitol-Fermenting Enterohemorrhagic Escherichia coli O157:H- Isolates from Czech Patients with Novel Plasmid Composition Not Previously Seen in German Isolates.

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Bauwens, Andreas; Marejková, Monika; Middendorf-Bauchart, Barbara; Prager, Rita; Kossow, Annelene; Zhang, Wenlan; Karch, Helge; Mellmann, Alexander; Bielaszewska, Martina

2017-12-01

Sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:H - strains, first identified in Germany, have emerged as important pathogens throughout Europe. Besides chromosomally encoded Shiga toxin 2a (the major virulence factor), several putative virulence loci, including the hly , etp , and sfp operons, encoding EHEC hemolysin, type II secretion system proteins, and Sfp fimbriae, respectively, are located on the 121-kb plasmid pSFO157 in German strains. Here we report novel SF EHEC O157:H - strains isolated from patients in the Czech Republic. These strains share the core genomes and chromosomal virulence loci encoding toxins ( stx 2a and the cdtV -ABC operon) and adhesins ( eae -γ, efa1 , lpfA O157OI-141 , and lpfA O157OI-154 ) with German strains but differ essentially in their plasmids. In contrast to all previously detected SF EHEC O157:H - strains, the Czech strains carry two plasmids, of 79 kb and 86 kb. The 79-kb plasmid harbors the sfp operon, but neither of the plasmids contains the hly and etp operons. Sequence analyses demonstrated that the 79-kb plasmid (pSFO157 258/98-1) evolved from pSFO157 of German strains by deletion of a 41,534-bp region via homologous recombination, resulting in loss of the hly and etp operons. The 86-kb plasmid (pSFO157 258/98-2) displays 98% sequence similarity to a 92.7-kb plasmid of an extraintestinal pathogenic E. coli bloodstream isolate. Our finding of this novel plasmid composition in SF EHEC O157:H - strains extends the evolutionary history of EHEC O157 plasmids. Moreover, the unique molecular plasmid characteristics permit the identification of such strains, thereby facilitating further investigations of their geographic distribution, clinical significance, and epidemiology. IMPORTANCE Since their first identification in Germany in 1989, sorbitol-fermenting enterohemorrhagic Escherichia coli O157:H - (nonmotile) strains have emerged as important causes of the life-threatening disease hemolytic

Sorbitol-Fermenting Enterohemorrhagic Escherichia coli O157:H− Isolates from Czech Patients with Novel Plasmid Composition Not Previously Seen in German Isolates

Science.gov (United States)

Bauwens, Andreas; Marejková, Monika; Middendorf-Bauchart, Barbara; Prager, Rita; Kossow, Annelene; Zhang, Wenlan; Karch, Helge

2017-01-01

ABSTRACT Sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:H− strains, first identified in Germany, have emerged as important pathogens throughout Europe. Besides chromosomally encoded Shiga toxin 2a (the major virulence factor), several putative virulence loci, including the hly, etp, and sfp operons, encoding EHEC hemolysin, type II secretion system proteins, and Sfp fimbriae, respectively, are located on the 121-kb plasmid pSFO157 in German strains. Here we report novel SF EHEC O157:H− strains isolated from patients in the Czech Republic. These strains share the core genomes and chromosomal virulence loci encoding toxins (stx2a and the cdtV-ABC operon) and adhesins (eae-γ, efa1, lpfAO157OI-141, and lpfAO157OI-154) with German strains but differ essentially in their plasmids. In contrast to all previously detected SF EHEC O157:H− strains, the Czech strains carry two plasmids, of 79 kb and 86 kb. The 79-kb plasmid harbors the sfp operon, but neither of the plasmids contains the hly and etp operons. Sequence analyses demonstrated that the 79-kb plasmid (pSFO157 258/98-1) evolved from pSFO157 of German strains by deletion of a 41,534-bp region via homologous recombination, resulting in loss of the hly and etp operons. The 86-kb plasmid (pSFO157 258/98-2) displays 98% sequence similarity to a 92.7-kb plasmid of an extraintestinal pathogenic E. coli bloodstream isolate. Our finding of this novel plasmid composition in SF EHEC O157:H− strains extends the evolutionary history of EHEC O157 plasmids. Moreover, the unique molecular plasmid characteristics permit the identification of such strains, thereby facilitating further investigations of their geographic distribution, clinical significance, and epidemiology. IMPORTANCE Since their first identification in Germany in 1989, sorbitol-fermenting enterohemorrhagic Escherichia coli O157:H− (nonmotile) strains have emerged as important causes of the life-threatening disease hemolytic

Ecology of E. coli O157:H7 and Salmonella enterica in the primary vegetable production chain

NARCIS (Netherlands)

Franz, E.; Bruggen, van A.H.C.

2008-01-01

There is an increased concern that plants might be more important as a carrier for human enteric pathogens like E. coli O157:H7 and Salmonella enterica serovars than previously thought. This review summarizes the knowledge available on the ecology of E. coli O157:H7 and Salmonella enterica in the

33 CFR Appendix D to Part 157 - Example of a Procedure for Dedicated Clean Ballast Tanks Operations

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Example of a Procedure for... ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Pt. 157, App. D Appendix D to Part 157—Example of a Procedure for Dedicated Clean Ballast Tanks Operations 1. Source. The example procedure for dedicated clean...

Genetically similar strains of Escherichia coli O157:H7 isolated from sheep, cattle and human patients

Directory of Open Access Journals (Sweden)

Söderlund Robert

2012-10-01

Full Text Available Abstract Background Comparatively little is known about the prevalence or the molecular characteristics of the zoonotic pathogen E. coli O157:H7 in the sheep reservoir. To investigate this and determine the host specificity of subclones of the bacterium, we have conducted a slaughterhouse prevalence study in sheep and compared the collected isolates to O157:H7 previously isolated from cattle and human patients. Results Verotoxin-producing O157:H7 was found in 11/597 (1.8% of samples from sheep in Swedish slaughterhouses, 9/492 faecal (1.8% and 2/105 ear samples (1.9%. All positive sheep were eaeA, hlyA, cdtV-B, vtx1, and partial sequencing of vtx2. The observed profiles were similar to those of cattle strains investigated previously. Conclusions The same pathogenic subtypes of VTEC O157:H7, including the highly virulent clade 8, appear to be present in both sheep and cattle in Sweden, suggesting strains can circulate freely between ruminant reservoirs.

Body protective compound-157 enhances alkali-burn wound healing in vivo and promotes proliferation, migration, and angiogenesis in vitro

Directory of Open Access Journals (Sweden)

Huang T

2015-04-01

Full Text Available Tonglie Huang,1,* Kuo Zhang,2,* Lijuan Sun,3 Xiaochang Xue,1 Cun Zhang,1 Zhen Shu,1 Nan Mu,1 Jintao Gu,1 Wangqian Zhang,1 Yukun Wang,1 Yingqi Zhang,1 Wei Zhang1 1State Key Laboratory of Cancer Biology, Department of Biopharmaceutics, School of Pharmacy, The Fourth Military Medical University, 2National Engineering Research Center for Miniaturized Detection Systems, School of Life Sciences, Northwest University, 3Department of Ophthalmology, Xijing Hospital, The Fourth Military Medical University, Xi’an, People’s Republic of China *These authors contributed equally to this work Abstract: Chemical burns take up a high proportion of burns admissions and can penetrate deep into tissues. Various reagents have been applied in the treatment of skin chemical burns; however, no optimal reagent for skin chemical burns currently exists. The present study investigated the effect of topical body protective compound (BPC-157 treatment on skin wound healing, using an alkali burn rat model. Topical treatment with BPC-157 was shown to accelerate wound closure following an alkali burn. Histological examination of skin sections with hematoxylin–eosin and Masson staining showed better granulation tissue formation, reepithelialization, dermal remodeling, and a higher extent of collagen deposition when compared to the model control group on the 18th day postwounding. BPC-157 could promote vascular endothelial growth factor expression in wounded skin tissues. Furthermore, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide and cell cycle analysis demonstrated that BPC-157 enhanced the proliferation of human umbilical vein endothelial cells (HUVECs. Transwell assay and wound healing assay showed that BPC-157 significantly promoted migration of HUVECs. We also observed that BPC-157 upregulated the expression of VEGF-a and accelerated vascular tube formation in vitro. Moreover, further studies suggested that BPC-157 regulated the phosphorylation level of

Protozoan Predation of Escherichia coli O157:H7 Is Unaffected by the Carriage of Shiga Toxin-Encoding Bacteriophages.

Directory of Open Access Journals (Sweden)

Carrie E Schmidt

Full Text Available Escherichia coli O157:H7 is a food-borne bacterium that causes hemorrhagic diarrhea and hemolytic uremic syndrome in humans. While cattle are a known source of E. coli O157:H7 exposure resulting in human infection, environmental reservoirs may also be important sources of infection for both cattle and humans. Bacteriophage-encoded Shiga toxins (Stx carried by E. coli O157:H7 may provide a selective advantage for survival of these bacteria in the environment, possibly through their toxic effects on grazing protozoa. To determine Stx effects on protozoan grazing, we co-cultured Paramecium caudatum, a common ciliate protozoon in cattle water sources, with multiple strains of Shiga-toxigenic E. coli O157:H7 and non-Shiga toxigenic cattle commensal E. coli. Over three days at ambient laboratory temperature, P. caudatum consistently reduced both E. coli O157:H7 and non-Shiga toxigenic E. coli populations by 1-3 log cfu. Furthermore, a wild-type strain of Shiga-toxigenic E. coli O157:H7 (EDL933 and isogenic mutants lacking the A subunit of Stx 2a, the entire Stx 2a-encoding bacteriophage, and/or the entire Stx 1-encoding bacteriophage were grazed with similar efficacy by both P. caudatum and Tetrahymena pyriformis (another ciliate protozoon. Therefore, our data provided no evidence of a protective effect of either Stx or the products of other bacteriophage genes on protozoan predation of E. coli. Further research is necessary to determine if the grazing activity of naturally-occurring protozoa in cattle water troughs can serve to decrease cattle exposure to E. coli O157:H7 and other Shiga-toxigenic E. coli.

Meat Science and Muscle Biology Symposium: Escherichia coli O157:H7, diet, and fecal microbiome in beef cattle.

Science.gov (United States)

Wells, J E; Kim, M; Bono, J L; Kuehn, L A; Benson, A K

2014-04-01

Shiga-toxigenic Escherichia coli, such as E. coli O157:H7, are foodborne zoonotic pathogens that can cause severe illness and death in humans. The gastrointestinal tract of ruminant animals has been identified as a primary habitat for E. coli O157:H7 and, in cattle, the hindgut tract appears to be a primary site for colonization. This pathogen has been found in cattle feces, on cattle hides, and in the production environment, and transmission to humans has occurred as a result of consumption of contaminated ground beef, water, and produce. Interventions to reduce the pathogen at beef harvest have significantly reduced the occurrence of the pathogen, but outbreaks and recalls due to the pathogen still occur for beef products. Interventions in the feedyard before harvest have had little success, but critical control points for implementing interventions are limited compared with the beef abattoir. The percentage of animals shedding E. coli O157:H7 in the feces can be highly variable from pen to pen, and the levels in the feces can vary from animal to animal. Animals colonized and shedding E. coli O157:H7 at high levels are a small fraction of animals in a pen but are important source for transferring the pathogen amongst the penmates. Recent research has indicated that diet may greatly influence the shedding of E. coli O157:H7. In addition, diet can influence the microbiota composition of the feces. However, little is known about the interaction between the indigenous microbiota and fecal shedding of E. coli O157:H7. Understanding the influence of indigenous microbiota on the colonization and shedding of E. coli O157:H7 will provide a potential avenue for intervention in the preharvest production environment not yet exploited.

Evidence for the interaction of the regulatory protein Ki-1/57 with p53 and its interacting proteins

International Nuclear Information System (INIS)

Nery, Flavia C.; Rui, Edmilson; Kuniyoshi, Tais M.; Kobarg, Joerg

2006-01-01

Ki-1/57 is a cytoplasmic and nuclear phospho-protein of 57 kDa and interacts with the adaptor protein RACK1, the transcription factor MEF2C, and the chromatin remodeling factor CHD3, suggesting that it might be involved in the regulation of transcription. Here, we describe yeast two-hybrid studies that identified a total of 11 proteins interacting with Ki-1/57, all of which interact or are functionally associated with p53 or other members of the p53 family of proteins. We further found that Ki-1/57 is able to interact with p53 itself in the yeast two-hybrid system when the interaction was tested directly. This interaction could be confirmed by pull down assays with purified proteins in vitro and by reciprocal co-immunoprecipitation assays from the human Hodgkin analogous lymphoma cell line L540. Furthermore, we found that the phosphorylation of p53 by PKC abolishes its interaction with Ki-1/57 in vitro

Sequential effect of phages and cold nitrogen plasma against Escherichia coli O157:H7 biofilms on different vegetables.

Science.gov (United States)

Cui, Haiying; Bai, Mei; Yuan, Lu; Surendhiran, Duraiarasan; Lin, Lin

2018-03-02

Escherichia coli O157:H7 (E. coli O157:H7) is one of the most common pathogens in fresh vegetables and fruits, and most of the diseases produced by E. coli O157:H7 are associated with biofilms. Cold nitrogen plasma (CNP) is a cold sterilization technique which has no residue. However to completely eliminate the biofilm on the surface of vegetables the processing power and time of CNP have to be enhanced, which will impact on the quality of fruits and vegetables. Thus the sequential treatment of CNP and phage techniques was engineered in this study. Compared to treatment performed separately, sequential treatment not only had more mild treatment conditions as 400W CNP treatment for 2min and 5% phage treatment for 30min, but also exhibited more remarkable effect on eradicating E. coli O157:H7 biofilms in vitro and on vegetables. The population of E. coli O157:H7 was approximately reduced by 2logCFU/cm 2 after individual treatment of 5% phages for 30min or 500W CNP for 3min. While the sequential treatment of CNP (400W, 2min) and phages (5%, 30min) reduced the E. coli O157:H7 viable count in biofilm by 5.71logCFU/cm 2 . Therefore, the sequential treatment holds a great promise to improve the current treatment systems of bacterial contamination on different vegetable surfaces. Copyright © 2018 Elsevier B.V. All rights reserved.

Electromagnetic transition probabilities in the natural-parity rotational bands of 155,157Gd

International Nuclear Information System (INIS)

Kusakari, H.; Oshima, M.; Uchikura, A.; Sugawara, M.; Tomotani, A.; Ichikawa, S.; Iimura, H.; Morikawa, T.; Inamura, T.; Matsuzaki, M.

1992-01-01

The ground-state rotational bands of 155 Gd and 157 Gd have been investigated through multiple Coulomb excitation with beams of 240-MeV 58 Ni and 305-MeV 81 Br. Gamma-ray branchings and E2/M1 mixing ratios were determined by γ-ray angular-distribution measurement. Nuclear lifetimes of levels up to I=21/2 and 23/2 for 155,157 Gd, respectively, have been measured using the Doppler-shift recoil-distance method. The observed signature dependence of M1 transition rates was found to be inverted in relation to the quasiparticle energy splitting. The data are analyzed in terms of the cranking model

Evidence of non-O157 Shiga toxin-producing Escherichia coli in the feces of meat goats at a U.S. slaughter plant.

Science.gov (United States)

Jacob, M E; Foster, D M; Rogers, A T; Balcomb, C C; Shi, X; Nagaraja, T G

2013-09-01

Shiga toxin-producing Escherichia coli (STEC) are important human pathogens, and attention to non-O157 serogroups has increased in recent years. Although cattle are normally considered the primary reservoir for STEC, recent illnesses associated with goat contact have indicated that these animals are important potential reservoirs for the organisms. The prevalence of STEC, particularly non-O157 serogroups, in U.S. goats has not been well described. Our objective was to determine the prevalence of six major non-O157 STEC serogroups in the feces of meat goats. Rectal contents from 296 goats were collected postevisceration at a slaughter plant in the southeastern United States over 9 days during a 12-week period from August through October 2012. Samples were enriched in E. coli broth, and DNA was extracted and used as template in an 11-gene multiplex PCR that detected six non-O157 serogroups (O26, O45, O103, O121, O111, and O145) and virulence genes. Samples were considered positive when at least one non-O157 STEC serotype was present with either stx₁ or stx₂. All six non-O157 serogroups were detected by PCR in our samples, and 14.5% of samples were positive for at least one serogroup. Prevalence of O26 was highest, with 6.4% of goat fecal samples positive. The prevalence of O45 was 3.4%, O103 was 4.4%, O111 was 4.1%, O121 was 1.4%, and O145 was 3.0%. Twenty-two (7.4%) of 296 fecal samples had more than one non-O157 serogroup detected in the feces. Two samples had evidence of three non-O157 STEC serogroups. Goats appear to be an important reservoir for non-O157 STEC, and further work to understand the characteristics, epidemiology, and ecology of STEC in these animals is warranted.

The seaweed fly (Coelopidae) can facilitate environmental survival and transmission of E. coli O157 at sandy beaches.

Science.gov (United States)

Swinscoe, Isobel; Oliver, David M; Gilburn, Andre S; Quilliam, Richard S

2018-06-19

The sustainable management of recreational beaches is essential for minimising risk of human exposure to microbial pathogens whilst simultaneously maintaining valuable ecosystem services. Decaying seaweed on public beaches is gaining recognition as a substrate for microbial contamination, and is a potentially significant reservoir for human pathogens in close proximity to beach users. Closely associated with beds of decaying seaweed are dense populations of the seaweed fly (Coelopidae), which could influence the spatio-temporal fate of seaweed-associated human pathogens within beach environments. Replicated mesocosms containing seaweed inoculated with a bioluminescent strain of the zoonotic pathogen E. coli O157:H7, were used to determine the effects of two seaweed flies, Coelopa frigida and C. pilipes, on E. coli O157:H7 survival dynamics. Multiple generations of seaweed flies and their larvae significantly enhanced persistence of E. coli O157:H7 in simulated wrack habitats, demonstrating that both female and male C. frigida flies are capable of transferring E. coli O157:H7 between individual wrack beds and into the sand. Adult fly faeces can contain significant concentrations of E. coli O157:H7, which suggests they are capable of acting as biological vectors and bridge hosts between wrack habitats and other seaweed fly populations, and facilitate the persistence and dispersal of E. coli O157:H7 in sandy beach environments. This study provides the first evidence that seaweed fly populations inhabiting natural wrack beds contaminated with the human pathogen E. coli O157:H7 have the capacity to amplify the hazard source, and therefore potential transmission risk, to beach users exposed to seaweed and sand in the intertidal zone. The risk to public health from seaweed flies and decaying wrack beds is usually limited by human avoidance behaviour; however, seaweed fly migration and nuisance inland plagues in urban areas could increase human exposure routes beyond the

Multidrug resistant enterohaemorrhagic Escherichia coli O157:H7 in ...

African Journals Online (AJOL)

Pigeons are commonly seen around human dwellings and in city centres. The movement of these birds from place to place makes them a veritable vehicle for environmental dissemination of pathogens. Enterohaemorrhagic E. coli (EHEC) O157:H7 can cause severe and sometimes fatal gastroenteritis in humans. This study ...

Study of quantum dot based on tin/yttrium mixed oxide doped with terbium to be used as biomarker

International Nuclear Information System (INIS)

Paganini, Paula P.; Felinto, Maria Claudia F.C.; Kodaira, Claudia A.; Brito, Hermi F.; Nunes, Luiz Antonio O.

2009-01-01

Quantum dots (semiconductors nanocrystals) have brought a promising field to develop a new generation of luminescent biomarkers. The use of lanthanides ions as luminescent markers has many advantages, for example a security method, low cost, high specificity and also the luminescence can be promptly measured with high sensibility and accuracy. These luminescent dots are functionalized with biomolecules. For the luminophore particle to be connect with biologicals molecules (for example covalent antibody) is necessary a previous chemical treatment to modify luminophore particle surface and this process is called functionalization. A prior chemical treatment with changes on the surface luminophore particle is necessary to couple the luminophore to biological molecules. This process can be used as coating which can protect these particles from being dissolved by acid as well as provide functional groups for biological conjugation. This work presents a photoluminescence study of nanoparticles based on tin/yttrium mixed oxides doped with terbium (SnO 2 /Y 2 O 3 :Tb 3+ ), synthesized by coprecipitation method. The nanoparticles were submitted to thermal treatment and characterized by X-Ray Powder Diffraction (XRD) that showed cassiterite phase formation and the influence of thermal treatment on nanoparticles structures. These nanoparticles going to be functionalized with a natural polysaccharide (chitosan) in order to form microspheres. These microspheres going to be irradiated with gamma radiation to sterilization and it can be evaluated if the nanoparticles are resistant to irradiation and they do not lose functionality with this process. (author)

Immunoconcentration of Shiga toxin-producing Escherichia coli O157 from animal faeces and raw meats by using Dynabeads anti-E. coli O157 and the VIDAS system

NARCIS (Netherlands)

Islam, M.A.; Heuvelink, A.E.; Talukder, K.A.; Boer, de E.

2006-01-01

To identify the reservoirs and routes of transmission of Shiga toxin-producing Escherichia coli (STEC) O157, sensitive detection and isolation methods are necessary. The sensitivity of traditional culture methods can be improved significantly by the inclusion of an immunoconcentration step,

Escherichia coli O157:H7--Discerning Facts from Fiction: An Integrated Research and Extension Project for Multiple Audiences.

Science.gov (United States)

Moore, D A; Smith, D R; Sischo, W M; Heaton, K; Besser, T E

2016-02-01

The O157:H7 (EcO157) epidemiology of Shiga-toxin-producing Escherichia coli (STEC) in cattle is complex, and myths about pre-harvest control are perpetuated. The objectives of this project were to identify perpetuated misinformation and inform four audiences about evidence-based risks and pre-harvest control of EcO157 by addressing: (i) EcO157 epidemiology and pre-harvest control; (ii) how food safety policy is created; and (iii) how to present accurate information about EcO157. An environmental scan using a daily Internet search helped identify themes for education. A literature review of pre-harvest control measures contributed to the development of educational materials (fact sheets, website, web presentations and conferences). Conference 1 was a webinar with 315 registrants, 10 countries including 41 US states and four Canadian provinces. Most participants felt confident in using their new knowledge, more than half felt confident enough to answer EcO157 questions from the public and many would recommend the recorded version of the webinar to colleagues. Conference 2 was live in the Washington, DC, area with most participants employed by the US government. All agreed that they better understood pre-harvest control, how food safety policy was made, and were confident they could create an effective message about STEC pre-harvest control. Videos were posted and received 348 Internet visitors within 2 months. Conference 3 was a webinar with a live audience and Twitter feeds, targeting people who give nutrition advice. Almost all ranked the programme good to excellent and relevant to their work. About 25% indicated that they would share: 'grass-fed beef is not safer than grain-fed', 25% would share information on effectiveness of cattle vaccines, and 14% would share information on message mapping. Across all conferences, major changes in knowledge included the following: there is no additional risk of EcO157 shedding from grain-fed versus grass-fed cattle, pre

Escherichia coli O157:H7 induces stronger plant immunity than Salmonella enterica Typhimurium SL1344.

Science.gov (United States)

Roy, Debanjana; Panchal, Shweta; Rosa, Bruce A; Melotto, Maeli

2013-04-01

Consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. In this study, we assessed plant defense responses induced by the fully pathogenic bacteria Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium SL1344 in both Arabidopsis thaliana and lettuce (Lactuca sativa). Unlike SL1344, O157:H7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. For instance, O157:H7 triggered stomatal closure even under high relative humidity, an environmental condition that generally weakens plant defenses against bacteria in the field and laboratory conditions. SL1344 instead induced a transient stomatal immunity. We also observed that PR1 gene expression was significantly higher in Arabidopsis leaves infected with O157:H7 compared with SL1344. These results suggest that plants may recognize and respond to some human pathogens more effectively than others. Furthermore, stomatal immunity can diminish the penetration of human pathogens through the leaf epidermis, resulting in low bacterial titers in the plant apoplast and suggesting that additional control measures can be employed to prevent food contamination. The understanding of how plant responses can diminish bacterial contamination is paramount in preventing outbreaks and improving the safety of food supplies.

Identification of E.coli O157:H7 in Intestinal and Urinary Tract Infection in Samawah City .

Directory of Open Access Journals (Sweden)

Mouna Akeel Hamed Al-Oebady

2017-02-01

Full Text Available This study was conducted to isolate E.coli O157: H7 as an important zoonotic pathogen from 150 samples (75 bloody stools and 75 urine samples of patients at many age groups range from one to 50 years old and for both sexes were collected from patients suffering from diarrhea and urinary tract infection who attend the Samawah Teaching Hospital for pediatrics and Gynecology of AL-Muthanna Governorate. The results revealed that 120 out of 150 were positive to E.coli O157:H7 at a percentage (80%. The number of E. coli isolates in bloody stool were 67(89.3% and urine samples were 53(70.6% gave positive results to E.coli O157:H7 .

Repetitive Immunosensor with a Fiber-Optic Device and Antibody-Coated Magnetic Beads for Semi-Continuous Monitoring of Escherichia coli O157:H7.

Science.gov (United States)

Taniguchi, Midori; Saito, Hirokazu; Mitsubayashi, Kohji

2017-09-19

A rapid and reproducible fiber-optic immunosensor for Escherichia coli O157:H7 ( E. coli O157:H7) was described. The biosensor consisted of a flow cell, an optical fiber with a thin Ni layer, and a PC linked fluorometer. First, the samples with E. coli O157:H7 were incubated with magnetic beads coated with anti- E. coli O157:H7 antibodies and anti- E. coli O157:H7 antibodies labeled cyanine 5 (Cy5) to make sandwich complexes. Then the Cy5-( E. coli O157:H7)-beads were injected into a flow cell and pulled to the magnetized Ni layer on the optical fiber set in the flow cell. An excitation light (λ = 635 nm) was used to illuminate the optical fiber, and the Cy5 florescent molecules facing the optical fiber were exposed to an evanescent wave from the optical fiber. The 670 nm fluorescent light was measured using a photodiode. Finally, the magnetic intensity of the Ni layer was removed and the Cy5- E. coli O157:H7-beads were washed out for the next immunoassay. E. coli O157:H7, diluted with phosphate buffer (PB), was measured from 1 × 10⁵ to 1 × 10⁷ cells/mL. The total time required for an assay was less than 15 min (except for the pretreatment process) and repeating immunoassay on one optical fiber was made possible.

The survival of Escherichia coli O157:H7 in the presence of Penicillium expansum and Glomerella cingulata in wounds on apple surfaces.

Science.gov (United States)

Riordan, D C; Sapers, G M; Annous, B A

2000-12-01

The survival of Escherichia coli O157:H7 in the presence of one of two plant pathogens, Penicillium expansum and Glomerella cingulata, in wounds on apples was observed during 14 days storage at room temperature (RT) and at 4 degrees C. The aim of this work was to determine if changes in apple physiology caused by the proliferation of fungal decay organisms would foster the survival of E. coli O157:H7. Trials were performed where (A) plant pathogens (4 log10 spores) were added to apple wounds 4 days before the wounds were inoculated with E. coli O157:H7 (3 log10 CFU g(-1) apple) (both RT and 4 degrees C storage), (B) plant pathogens and E. coli O157:H7 were added on the same day (both RT and 4 degrees C storage), and (C) E. coli O157:H7 was added 2 days (RT storage) and 4 days (4 degrees C storage) before plant pathogens. In all trials E. coli O157:H7 levels generally declined to cingulata at RT E. coli O157:H7 numbers increased from 3.18 to 4.03 log10 CFU g(-1) in the apple wound during trial A, from 3.26 to 6.31 log10 CFU g(-1) during trial B, and from 3.22 to 6.81 log10 CFU g(-1) during trial C. This effect is probably a consequence of the attendant rise in pH from 4.1 to approximately 6.8, observed with the proliferation of G. cingulata rot. Control apples (inoculated with E. coli O157:H7 only) were contaminated with opportunistic decay organisms at RT during trials A and B, leading to E. coli O157:H7 death. However, E. coli O157:H7 in control apples in trial C, where no contamination occurred, increased from 3.22 to 5.97 log10 CFU g(-1). The fact that E. coli O157:H7 can proliferate in areas of decay and/or injury on fruit highlights the hazards associated with the use of such fruit in the production of unpasteurized juice.

Selegiline Ameliorates Depression-Like Behavior in Mice Lacking the CD157/BST1 Gene, a Risk Factor for Parkinson’s Disease

Directory of Open Access Journals (Sweden)

Satoka Kasai

2017-05-01

Full Text Available Parkinson’s disease (PD, a neurodegenerative disorder, is accompanied by various non-motor symptoms including depression and anxiety, which may precede the onset of motor symptoms. Selegiline is an irreversible monoamine oxidase-B (MAO-B inhibitor, and is widely used in the treatment of PD and major depression. However, there are few reports about the effects of selegiline on non-motor symptoms in PD. The aim of this study was to explore the antidepressant and anxiolytic effects of selegiline, using CD157/BST1 knockout (CD157 KO mouse, a PD-related genetic model displaying depression and anxiety, compared with other antiparkinsonian drugs and an antidepressant, and was to investigate the effects of selegiline on biochemical parameters in emotion-related brain regions. A single administration of selegiline (1–10 mg/kg dose-dependently reduced immobility time in the forced swimming test (FST in CD157 KO mice, but not C57BL/6N wild-type (WT mice. At 10 mg/kg, but not 3 mg/kg, selegiline significantly increased climbing time in CD157 KO mice. A single administration of the antiparkinsonian drugs pramipexole (a dopamine (DA D2/D3 receptor agonist or rasagiline (another MAO-B inhibitor, and repeated injections of a noradrenergic and specific serotonergic antidepressant (NaSSA, mirtazapine, also decreased immobility time, but did not increase climbing time, in CD157 KO mice. The antidepressant-like effects of 10 mg/kg selegiline were comparable to those of 10 mg/kg rasagiline, and tended to be stronger than those of 1 mg/kg rasagiline. After the FST, CD157 KO mice showed decreases in striatal and hippocampal serotonin (5-HT content, cortical norepinephrine (NE content, and plasma corticosterone concentration. A single administration of selegiline at 10 mg/kg returned striatal 5-HT, cortical NE, and plasma corticosterone levels to those observed in WT mice. In the open field test (OFT, repeated administration of mirtazapine had anxiolytic effects

Preparation of a novel fluorescence probe of terbium-europium co-luminescence composite nanoparticles and its application in the determination of proteins

Energy Technology Data Exchange (ETDEWEB)

Gao Feng [College of Chemistry and Materials Science, Anhui Key Laboratory of Chemo/Biosensing, Anhui Normal University, Wuhu 241000 (China)], E-mail: summit8848cn@hotmail.com; Luo Fabao; Tang Lijuan; Dai Lu [College of Chemistry and Materials Science, Anhui Key Laboratory of Chemo/Biosensing, Anhui Normal University, Wuhu 241000 (China); Wang Lun [College of Chemistry and Materials Science, Anhui Key Laboratory of Chemo/Biosensing, Anhui Normal University, Wuhu 241000 (China)], E-mail: wanglun@mail.ahnu.edu.cn

2008-03-15

Terbium-europium Tb-Eu/acetylacetone(acac)/poly(acrylamide) (PAM) co-luminescence composite nanoparticles were successfully prepared using the ultrasonic approach. The as-prepared composite nanoparticles show the characteristic emission spectra of Tb{sup 3+}, located at 496 and 549 nm. Furthermore, the nanoparticles are water soluble, stable and have extremely narrow emission bands and high internal fluorescence quantum yield due to the co-luminescence effect. Further studies indicate that proteins can interact with the nanoparticles and induce the fluorescence quenching of the nanoparticles. Based on the fluorescence quenching of nanopaticles in the presence of proteins, a novel method for the sensitive determination of trace amounts of proteins was proposed. Under the optimal experimental conditions, the linear ranges of calibration curves are 0-3.5 {mu}g mL{sup -1} for human serum albumin (HSA) and 0-4.0 {mu}g mL{sup -1} for {gamma}-globulin ({gamma}-IgG), respectively. The limits of detection are 7.1 for HSA and 6.7ng mL{sup -1} for {gamma}-IgG, respectively. The method was applied to the quantification of proteins in synthetic samples and actual human serum samples with satisfactory results. This proposed method is sensitive, simple and has potential application in the clinical assay of proteins.

Distribution of the urease gene cluster among and urease activities of enterohemorrhagic Escherichia coli O157 isolates from humans

NARCIS (Netherlands)

Friedrich, Alexander W; Köck, Robin; Bielaszewska, Martina; Zhang, Wenlan; Karch, Helge; Mathys, Werner

Enterohemorrhagic Escherichia coli (EHEC) O157 strains belong to two closely related major groups, which are differentiated by their sorbitol fermentation phenotypes. Here we studied the conservation of urease genes and their expression in sorbitol-fermenting (SF) and non-SF EHEC O157 isolates. PCR

Molecular characterization of Verocytotoxigenic Escherichia coli O157:H7 isolates from Argentina by Multiple-Loci VNTR Analysis (MLVA)

Science.gov (United States)

Bustamante, Ana V.; Lucchesi, Paula M.A.; Parma, Alberto E.

2009-01-01

The aim of this work was to adapt described MLVA protocols to the molecular typing and characterization of VTEC O157:H7 isolates from Argentina. Nine VNTR loci were amplified by PCR showing diversity values from 0.49 to 0.73. Nine MLVA profiles were observed and the cluster analysis indicated both unrelated and closely related VTEC O157:H7 strains. In spite of the limited number of isolates studied, the panel of VNTR used made it possible to perform a first approach of the high genetic diversity of native strains of O157:H7 by MLVA. PMID:24031443

Selection, Identification, and Binding Mechanism Studies of an ssDNA Aptamer Targeted to Different Stages of E. coli O157:H7.

Science.gov (United States)

Zou, Ying; Duan, Nuo; Wu, Shijia; Shen, Mofei; Wang, Zhouping

2018-06-06

Enterohemorrhagic Escherichia coli O157:H7 ( E. coli O157:H7) is known as an important food-borne pathogen related to public health. In this study, aptamers which could bind to different stages of E. coli O157:H7 (adjustment phase, log phase, and stationary phase) with high affinity and specificity were obtained by the whole cell-SELEX method through 14 selection rounds including three counter-selection rounds. Altogether, 32 sequences were obtained, and nine families were classified to select the optimal aptamer. To analyze affinity and specificity by flow cytometer, an ssDNA aptamer named Apt-5 was picked out as the optimal aptamer that recognizes different stages of E. coli O157:H7 specifically with the K d value of 9.04 ± 2.80 nM. In addition, in order to study the binding mechanism, target bacteria were treated by proteinase K and trypsin, indicating that the specific binding site is not protein on the cell membrane. Furthermore, when we treated E. coli O157:H7 with EDTA, the result showed that the binding site might be lipopolysaccharide (LPS) on the outer membrane of E. coli O157:H7.

Studies on the rare earth complexes with pyridine derivatives and their N-oxide(II) - Synthesis and properties of fluorescent solid complexes of samarium, europium, gadolium and terbium chlorides with 2,2'-bipyridine-N,N'-dioxide

International Nuclear Information System (INIS)

Minyu, T.; Ning, T.; Yingli, Z.; Jiyuan, B.

1985-01-01

The solid complexes of rare earth nitrates perchlorates and thiocyanates with 2,2'-bipyridine-N,N'-dioxide (bipyO/sub 2/) have been reported. However, the corresponding complexes of other rear earth chlorides have not been investigated except lanthanum, cerium and yttrium. As an extension of our previous work on the synthesis of complexes of praseodymium and neodymium chlorides wiht bipoyO/sub 2/, the authors have now prepared fluorescent solid complexes of samarium, europium, gadolium and terbium chlorides with biphyO/sub 2/, using methanol as a reaction medium. The new synthesized compounds have been identified by means of elemental analysis, infrared spectrometry, conductometry, differential thermal analysis (DTA), thermogravimetry (TG) and X-ray powder diffraction

Karistusseadustiku § 157² probleeme Internetiga seotud identiteedivarguste kontekstis / Merika Nimmo

Index Scriptorium Estoniae

Nimmo, Merika, 1990-

2014-01-01

Karistusseadustikus §-s 157² sisalduv kuriteokoosseis ning selle reguleerimisala ja efektiivsus Internetiga seotud identiteedivarguste kontekstis. Artikkel põhineb Tartu Ülikooli õigusteaduskonnas 2014. a kevadel kaitstud magistritööl, mille teemaks on „Internetiga seotud identiteedivargus ja selle regulatsioon Eesti karistusõiguses“

Elimination of Escherichia coli O157:H7 in meats by gamma irradiation

International Nuclear Information System (INIS)

Thayer, D.W.; Boyd, G.

1993-01-01

Undercooked and raw meat has been linked to outbreaks of hemorrhagic diarrhea due to the presence of Escherichia coli O157:H7; therefore, treatment with ionizing radiation was investigated as a potential method for the elimination of this organism. Response-surface methods were used to study the effects of irradiation dose (0 to 2.0 kGy), temperature (-20 to +20 degrees C), and atmosphere (air and vacuum) on E. coli O157:H7 in mechanically deboned chicken meat. Differences in irradiation dose and temperature significantly affected the results. Ninety percent of the viable E. coli in chicken meat was eliminated by doses of 0.27 kGy at +5 degrees C and 0.42 kGy at -5 degrees C. Small, but significant, differences in radiation resistance by E. coli were found when finely ground lean beef rather than chicken was the substrate. Unlike nonirradiated samples, no measurable verotoxin was found in finely ground lean beef which had been inoculated with 10(4.8) CFU of E. coli O157:H7 per g, irradiated at a minimum dose of 1.5 kGy, and temperature abused at 35 degrees C for 20 h. Irradiation is an effective method to control this food-borne pathogen

Inactivation of E. coli O157:H7 on blueberries by electrolyzed water, ultraviolet light, and ozone.

Science.gov (United States)

Kim, Chyer; Hung, Yen-Con

2012-04-01

Increased interest in blueberries due to their nutritional and health benefits has led to an increase in consumption. However, blueberries are consumed mostly raw or minimally processed and are susceptible to microbial contamination like other type of fresh produce. This study was, therefore, undertaken to evaluate the efficacy of electrostatic spray of electrolyzed oxidizing (EO) water, UV light, ozone, and a combination of ozone and UV light in killing Escherichia coli O157:H7 on blueberries. A 5-strain mixture of E. coli O157:H7 were inoculated on the calyx and skin of blueberries and then subjected to the treatments. Electrostatic EO water spray reduced initial populations of E. coli O157:H7 by only 0.13 to 0.24 log CFU/g and 0.88 to 1.10 log CFU/g on calyx and skin of blueberries, respectively. Ozone treatment with 4000 mg/L reduced E. coli O157:H7 by only 0.66 and 0.72 log CFU/g on calyx and skin of blueberries, respectively. UV light at 20 mW/cm² for 10 min was the most promising single technology and achieved 2.14 and greater than 4.05 log reductions of E. coli O157:H7 on the calyx and skin of blueberries, respectively. The combination treatment of 1 min ozone and followed by a 2 min UV achieved more than 1 and 2 log additional reductions on blueberry calyx than UV or ozone alone, respectively. Outbreaks of foodborne illnesses have been associated with consumption of fresh produce. Many methods for removing pathogens as well as minimizing their effect on quality of treated produce have been investigated. UV technology and its combination with ozone used in this study to inactive E. coli O157:H7 on blueberries was found effective. Results from this study may help producers and processors in developing hurdle technologies for the delivery of safer blueberries to consumers. © 2012 Institute of Food Technologists®

76 FR 48903 - 157th Meeting of the Advisory Council on Employee Welfare and Pension Benefit Plans; Notice of...

Science.gov (United States)

2011-08-09

... DEPARTMENT OF LABOR Employee Benefits Security Administration 157th Meeting of the Advisory Council on Employee Welfare and Pension Benefit Plans; Notice of Meeting Pursuant to the authority... 157th open meeting of the Advisory Council on Employee Welfare and Pension Benefit Plans (also known as...

Genomic Variability of O Islands Encoding Tellurite Resistance in Enterohemorrhagic Escherichia coli O157:H7 Isolates

Science.gov (United States)

Taylor, Diane E.; Rooker, Michelle; Keelan, Monika; Ng, Lai-King; Martin, Irene; Perna, Nicole T.; Burland, N. T. Valerie; Blattner, Fredrick R.

2002-01-01

Strains of Escherichia coli causing enterohemorrhagic colitis belonging to the O157:H7 lineage are reported to be highly related. Fifteen strains of E. coli O157:H7 and 1 strain of E. coli O46:H− (nonflagellated) were examined for the presence of potassium tellurite resistance (Ter). Ter genes comprising terABCDEF were shown previously to be part of a pathogenicity island also containing integrase, phage, and urease genes. PCR analysis, both conventional and light cycler based, demonstrated that about one-half of the Ter E. coli O157:H7 strains (6 of 15), including the Sakai strain, which has been sequenced, carried a single copy of the Ter genes. Five of the strains, including EDL933, which has also been sequenced, contained two copies. Three other O157:H7 strains and the O46:H− strain did not contain the Ter genes. In strains containing two copies, the Ter genes were associated with the serW and serX tRNA genes. Five O157:H7 strains resembled the O157 Sakai strain whose sequence contained one copy, close to serX, whereas in one isolate the single copy was associated with serW. There was no correlation between Ter and the ability to produce Shiga toxin ST1 or ST2. The Ter MIC for most strains, containing either one or two copies, was 1,024 μg/ml, although for a few the MIC was intermediate, 64 to 128 μg/ml, which could be increased to 512 μg/ml by pregrowth of strains in subinhibitory concentrations of potassium tellurite. Reverse transcriptase PCR analysis confirmed that in most strains Ter was constitutive but that in the rest it was inducible and involved induction of terB and terC genes. Only the terB, -C, -D, and -E genes are required for Ter. The considerable degree of homology between the ter genes on IncH12 plasmid R478, which originated in Serratia marcescens, and pTE53, from an E. coli clinical isolate, suggests that the pathogenicity island was acquired from a plasmid. This work demonstrates diversity among E. coli O157:H7 isolates, at least as

Hyperfine structure in the Gd II spectrum and the nuclear electric quadrupole moment of 157Gd

International Nuclear Information System (INIS)

Clieves, H.P.; Steudel, A.

1979-01-01

The hyperfine structure of 157 Gd was investigated in 20 Gd II lines by means of a photoelectric recording Fabry-Perot interferometer with digital data processing. The hyperfine splitting factors, A and B, were obtained by computer fits to the observed line structures. Using a multiconfigurational set of wave functions in intermediate coupling derived by Wyart, mono-electronic parameters were deduced by a parametric treatment. The nuclear electric quadrupole moment of 157 Gd was evaluated from the quadrupole interaction of the 5d electron in 4f 7 5d6s, the 5d electron in 4f 7 5d6p, and the 6p electron in 4f 7 5d6p. The three values obtained for the quadrupole moment agree very well. The final result, corrected for Sternheimer shielding, is Q( 157 Gd) = 1.34(7) x 10 -24 cm 2 . (orig.) [de

Biocontrol of Escherichia coli O157:H7 on fresh-cut spinach and lettuce using a bacteriophage cocktail

Science.gov (United States)

The effect of an E. coli O157:H7-specific bacteriophage cocktail (EcoShield™) was evaluated against nalidixic acid resistant (NalR) E. coli O157:H7 strains in either a) laboratory medium or b) on leafy greens. Laboratory medium cultures were inoculated with 5 log CFU/ml and treated with 7 log PFU/ml...

Risk factors associated with faecal shedding of verocytotoxin-producing Escherichia coli O157 in eight known-infected Danish dairy herds

DEFF Research Database (Denmark)

Rugbjerg, Helene; Nielsen, Eva Møller; Andersen, Jens Strodl

2003-01-01

A risk-factor study was performed in eight dairy herds found to excrete verocytotoxin-producing Escherichia coli (VTEC) O157 in a former prevalence study. Associations between excretion of VTEC O157 and management factors such as housing and feeding were analysed in a generalised linear mixed mod...... days with the mother after calving. Calves aged 5-24 months that had been moved within the last 2 weeks had a higher risk, but risk was reduced if fed barley silage. Cows fed grain or molasses had a higher risk of excreting VTEC O157....

Carvacrol and p-cymene inactivate Escherichia coli O157:H7 in apple juice

Directory of Open Access Journals (Sweden)

Roller Sibel

2005-06-01

Full Text Available Abstract Background Outbreaks of food poisoning associated with drinking un-pasteurised apple juice contaminated with enterohaemorrhagic Escherichia coli O157:H7 are a cause of serious illness and occasionally death. Whilst a well-established heat process (pasteurisation will readily eliminate the pathogen, some consumers are demanding more fresh-like foods that have not been subjected to processing methods that are perceived as severe and may lead to loss of flavour and vitamins. Therefore, alternative methods are being investigated to replace pasteurisation and improve the safety of minimally-processed juices. The addition of natural antimicrobial substances such as the phenolic substances carvacrol and p-cymene (derived from the essential oils of herbs and spices provides a potential new route to assure safety and extend the shelf-life of raw fruit juices. The aim of this study was to evaluate the addition of very low concentrations (0.25–1.25 mM of carvacrol and p-cymene both individually and in combination as a novel means of controlling Escherichia coli O157:H7 in un-pasteurised apple juice. Results When inoculated at a level of 4 log CFU/ml into un-pasteurised apple juice (pH 3.20 ± 0.06, Escherichia coli O157:H7 survived for up to 3 and 19 days at 25° and 4°C, respectively. Treatment of the juice with 1.25 mM carvacrol or p-cymene reduced the numbers of E. coli O157:H7 to undetectable levels within 1–2 days at both storage temperatures. The effective concentrations of carvacrol could be reduced even further by combining it at 0.5 mM with cymene at 0.25 mM. The phenolic compounds were biocidal against both spoilage yeasts and E. coli O157:H7 thereby increasing the shelf-life and improving the safety of un-pasteurised apple juice, particularly when stored at chill temperatures. Conclusion The results showed that the natural antimicrobial compounds carvacrol and p-cymene could potentially be used to extend the shelf life and improve

Study of the role of complete fusion in the reaction of 48Ca and 56Fe with cerium and terbium

International Nuclear Information System (INIS)

Morrissey, D.J.

1978-05-01

48 Ca and 56 Fe beams from the Super HILAC accelerator were used to irradiate thick metal foils of cerium and terbium. Product gamma ray activities were detected offline and individual products were identified by half-life, gamma ray energy and gamma ray abundances. The production cross sections were iteratively fit to charge and mass dispersions to allow correction for parent decay and calculation of mass yields. From the mass yield curves contributions from quasielastic transfer, deep inelastic transfer and complete fusion reaction mechanisms were interred. Complete fusion was made up on contributions from both evaporation residue and fusion-fission products for the 48 Ca induced reactions. However, only fusion-fission products were detected in the 56 Fe induced reactions. Critical angular momenta for fusion were found to be 82 +- 8 h for 48 Ca + 159 Tb and 34 +- 5 h for 56 Fe + 140 Ce, which can be compared with 53 +- 8 h for 12 C + 197 Au (Natowitz, 1970) and 86 +- 5 h for 40 Ar + 165 Ho (Hanappe, 1973). All of these reactions lead to essentially the same compound nucleus and seem to show the dramatic decline in complete fusion for heavy ions larger than 40 Ar. The prediction of this decline was found to be beyond the model calculations of Bass and the critical distance approach of Glas and Mosel

Cross contamination of Escherichia coli O157:H7 between lettuce and wash water during home-scale washing.

Science.gov (United States)

Jensen, Dane A; Friedrich, Loretta M; Harris, Linda J; Danyluk, Michelle D; Schaffner, Donald W

2015-04-01

Lettuce and leafy greens have been implicated in multiple foodborne disease outbreaks. This study quantifies cross contamination between lettuce pieces in a small-scale home environment. A five-strain cocktail of relevant Escherichia coli O157:H7 strains was used. Bacterial transfer between single inoculated lettuce leaf pieces to 10 non-inoculated lettuce leaf pieces that were washed in a stainless steel bowl of water for 30 s, 1 min, 2 min, and 5 min was quantified. Regardless of washing time, the wash water became contaminated with 90-99% of bacteria originally present on the inoculated lettuce leaf piece. The E. coli O157:H7 concentration on initially inoculated leaf pieces was reduced ∼ 2 log CFU. Each initially uncontaminated lettuce leaf piece had ∼ 1% of the E. coli O157:H7 from the inoculated lettuce piece transferred to it after washing, with more transfer occurring during the shortest (30 s) and longest (5 min) wash times. In all cases the log percent transfer rates were essentially normally distributed. In all scenarios, most of the E. coli O157:H7 (90-99%) transferred from the inoculated lettuce pieces to the wash water. Washing with plain tap water reduces levels of E. coli O157:H7 on the inoculated lettuce leaf pieces, but also spreads contamination to previously uncontaminated leaf pieces. Copyright © 2014 Elsevier Ltd. All rights reserved.

Aislamiento y caracterización de Escherichia coli O157 en productos cárnicos bovinos y medias reses en la provincia de Tucumán

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María A Jure

2015-06-01

Full Text Available Escherichia coli O157 es un patógeno emergente asociado a diarrea, colitis hemorrágica y síndrome urémico hemolítico. Los productos cárnicos constituyen una importante fuente de contaminación con este microorganismo. Los objetivos de este estudio fueron establecer la frecuencia de detección de E. coli O157 en productos cárnicos y media res en la provincia de Tucumán, caracterizar los factores de virulencia de los aislamientos obtenidos, establecer la relación clonal entre cepas regionales mediante electroforesis de campo pulsado y comparar con lo consignado en la base de datos nacional. Desde 2004 hasta 2013 se analizaron 169 muestras de carne picada, 35 embutidos y 216 esponjados de media res. Se identificaron 13 aislamientos de E. coli O157; 6 de ellos fueron O157:H7 productores de toxina Shiga y se caracterizaron como stx2c(vh-a/eae/ehxA (n = 5 y stx2/eae/ehxA (n = 1; los 7 aislamientos de E. coli O157 no toxigénicos fueron O157:NT(n = 4,O157:NM (n = 1,O157:ND (n = 1 y O157:H16 (n = 1. Los patrones de PFGE fueron diferentes entre sí y de los registrados en la base de datos nacional. Se concluye que existe gran diversidad genética en los aislamientos de E. coli O157 circulantes en nuestra región.

Carriage of stx2a differentiates clinical and bovine-biased strains of Escherichia coli O157.

Directory of Open Access Journals (Sweden)

Smriti Shringi

Full Text Available Shiga toxin (Stx are cardinal virulence factors of enterohemorrhagic E. coli O157:H7 (EHEC O157. The gene content and genomic insertion sites of Stx-associated bacteriophages differentiate clinical genotypes of EHEC O157 (CG, typical of clinical isolates from bovine-biased genotypes (BBG, rarely identified among clinical isolates. This project was designed to identify bacteriophage-mediated differences that may affect the virulence of CG and BBG.Stx-associated bacteriophage differences were identified by whole genome optical scans and characterized among >400 EHEC O157 clinical and cattle isolates by PCR.Optical restriction maps of BBG strains consistently differed from those of CG strains only in the chromosomal insertion sites of Stx2-associated bacteriophages. Multiplex PCRs (stx1, stx2a, and stx2c as well as Stx-associated bacteriophage-chromosomal insertion site junctions revealed four CG and three BBG that accounted for >90% of isolates. All BBG contained stx2c and Stx2c-associated bacteriophage-sbcB junctions. All CG contained stx2a and Stx2a-associated bacteriophage junctions in wrbA or argW.Presence or absence of stx2a (or another product encoded by the Stx2a-associated bacteriophage is a parsimonious explanation for differential virulence of BBG and CG, as reflected in the distributions of these genotypes in humans and in the cattle reservoir.

Overexpressed Proteins in Hypervirulent Clade 8 and Clade 6 Strains of Escherichia coli O157:H7 Compared to E. coli O157:H7 EDL933 Clade 3 Strain.

Directory of Open Access Journals (Sweden)

Natalia Amigo

Full Text Available Escherichia coli O157:H7 is responsible for severe diarrhea and hemolytic uremic syndrome (HUS, and predominantly affects children under 5 years. The major virulence traits are Shiga toxins, necessary to develop HUS and the Type III Secretion System (T3SS through which bacteria translocate effector proteins directly into the host cell. By SNPs typing, E. coli O157:H7 was separated into nine different clades. Clade 8 and clade 6 strains were more frequently associated with severe disease and HUS. In this study, we aimed to identify differentially expressed proteins in two strains of E. coli O157:H7 (clade 8 and clade 6, obtained from cattle and compared them with the well characterized reference EDL933 strain (clade 3. Clade 8 and clade 6 strains show enhanced pathogenicity in a mouse model and virulence-related properties. Proteins were extracted and analyzed using the TMT-6plex labeling strategy associated with two dimensional liquid chromatography and mass spectrometry in tandem. We detected 2241 proteins in the cell extract and 1787 proteins in the culture supernatants. Attention was focused on the proteins related to virulence, overexpressed in clade 6 and 8 strains compared to EDL933 strain. The proteins relevant overexpressed in clade 8 strain were the curli protein CsgC, a transcriptional activator (PchE, phage proteins, Stx2, FlgM and FlgD, a dienelactone hydrolase, CheW and CheY, and the SPATE protease EspP. For clade 6 strain, a high overexpression of phage proteins was detected, mostly from Stx2 encoding phage, including Stx2, flagellin and the protease TagA, EDL933_p0016, dienelactone hydrolase, and Haemolysin A, amongst others with unknown function. Some of these proteins were analyzed by RT-qPCR to corroborate the proteomic data. Clade 6 and clade 8 strains showed enhanced transcription of 10 out of 12 genes compared to EDL933. These results may provide new insights in E. coli O157:H7 mechanisms of pathogenesis.

Physical Covering to control Escherichia coli O157:H7 and Salmonella in Static and Windrow Composting Process

Science.gov (United States)

This study investigated the effect of 30-cm covering of finished compost on survival of E. coli O157:H7 and Salmonella in active static and windrow composting systems. Feedstock inoculated with E. coli O157:H7 (7.41 log CFU/g) and Salmonella (6.46 log CFU/g) were placed in biosentry tubes (7.5 cm di...

Applications of immunomagnetic capture and time-resolved fluorescence to detect outbreak Escherichia coli O157 and Salmonella in alfalfa sprouts

Science.gov (United States)

Tu, Shu-I.; Gordon, Marsha; Fett, William F.; Gehring, Andrew G.; Irwin, Peter L.

2004-03-01

Commercially available alfalfa seeds were inoculated with low levels (~ 4 CFU/g) of pathogenic bacteria. The inoculated seeds were then allowed to sprout in sterile tap water at 22°C. After 48 hours, the irrigation water and sprouts were separately transferred to bovine heart infusion (BHI) media. The microbes in the BHI samples were allowed to grow for 4 hours at 37°C and 160 rpm. Specific immunomagnetic beads (IMB) were then applied to capture the E.coli O157 and/or Salmonella in the growth media. Separation and concentration of IMB-captured pathogens were achieved using magnetic separators. The captured E. coli O157:H7 and Salmonella spp were further tagged with europium (Eu) labeled anti-E. coli O157 antibodies and samarium (Sm) labeled anti-Salmonella antibodies, respectively. After washing, the lanthanide labels were extracted out from the complexes by specific chelators to form strongly fluorescent chelates. The specific time-resolved fluorescence (TRF) associated with Eu or Sm was measured to estimate the extent of capture of the E. coli O157 and Salmonella, respectively. The results indicated that the approach could detect E. coli O157 and Salmonella enterica from the seeds inoculated with ~ 4 CFU/g of the pathogens. Non-targeted bacteria, e.g., Aeromonas and Citrobacter exhibited essentially no cross reactivity. Since the pathogen detection from the sprouts was achieved within 6 hours, the developed methodology could be use as a rapid, sensitive and specific screening process for E. coli O157 and Salmonella enterica in this popular salad food.

Evaluation of immunomagnetic separation and PCR for the detection of Escherichia coli O157 in animal feces and meats

NARCIS (Netherlands)

Islam, M.A.; Heuvelink, A.E.; Talukder, K.A.; Zwietering, M.H.; Boer, de E.

2006-01-01

Series of animal feces and meat samples artificially contaminated with strains of Escherichia coli O157 isolated from different sources were tested by both an immunomagnetic separation (IMS)-based method and a PCR method using primers specific for a portion of the rfbE gene of E. coli O157. IMS is

Occurrence of Escherichia coli O157 in a river used for fresh ...

African Journals Online (AJOL)

PRECIOUS

2010-01-11

Jan 11, 2010 ... source of water for large scale fresh produce irrigation and herd .... Duncan's multiple range tests were used to compare the means of parameters for the .... Longitudinal study of faecal shedding of Escherichia coli O157: H7 in.

Analysis of whole genome sequencing for the Escherichia coli O157:H7 typing phages.

Science.gov (United States)

Cowley, Lauren A; Beckett, Stephen J; Chase-Topping, Margo; Perry, Neil; Dallman, Tim J; Gally, David L; Jenkins, Claire

2015-04-08

Shiga toxin producing Escherichia coli O157 can cause severe bloody diarrhea and haemolytic uraemic syndrome. Phage typing of E. coli O157 facilitates public health surveillance and outbreak investigations, certain phage types are more likely to occupy specific niches and are associated with specific age groups and disease severity. The aim of this study was to analyse the genome sequences of 16 (fourteen T4 and two T7) E. coli O157 typing phages and to determine the genes responsible for the subtle differences in phage type profiles. The typing phages were sequenced using paired-end Illumina sequencing at The Genome Analysis Centre and the Animal Health and Veterinary Laboratories Agency and bioinformatics programs including Velvet, Brig and Easyfig were used to analyse them. A two-way Euclidian cluster analysis highlighted the associations between groups of phage types and typing phages. The analysis showed that the T7 typing phages (9 and 10) differed by only three genes and that the T4 typing phages formed three distinct groups of similar genomic sequences: Group 1 (1, 8, 11, 12 and 15, 16), Group 2 (3, 6, 7 and 13) and Group 3 (2, 4, 5 and 14). The E. coli O157 phage typing scheme exhibited a significantly modular network linked to the genetic similarity of each group showing that these groups are specialised to infect a subset of phage types. Sequencing the typing phage has enabled us to identify the variable genes within each group and to determine how this corresponds to changes in phage type.

Detección de Escherichia coli O157: H7 en carne picada fresca y hamburguesas congeladas Escherichia coli O157: H7 detection in fresh ground beef and hamburgers

Directory of Open Access Journals (Sweden)

M. A. Marzocca

2006-03-01

Full Text Available Escherichia coli O157:H7 es un patógeno emergente asociado a enfermedades transmitidas por alimentos. En el año 1982 fue reconocido por primera vez, en los Estados Unidos, como causante de dos brotes de colitis hemorrágica. Hoy se sabe que la mayoría de los casos de síndrome urémico hemolítico son ocasionados por este microorganismo. El objetivo del trabajo fue detectar su presencia en carne picada fresca y hamburguesas congeladas, muestras obtenidas en puntos de venta de nuestra cadena de supermercados en un total de 37 y 43, respectivamente, en el período comprendido entre abril de 2003 y agosto de 2004. Las mismas fueron procesadas utilizando el caldo selectivo para enriquecimiento EC modificado conteniendo novobiocina, seguido de la aplicación de un método de inmunocaptura (TECRA E. COLI O157 IMMUNOCAPTURE TM ECOICM 20, y posterior aislamiento en agar MacConkey sorbitol suplementado con cefixima y telurito de potasio y un medio cromogénico. Las cepas sospechosas fueron caracterizadas a genotípicamente mediante la detección de los genes de virulencia stx1, stx2, eaeA y EHEC-hlyA por PCR e hibridación con sondas genéticas, b fenotípicamente mediante la determinación del serotipo, sensibilidad a los antimicrobianos por el método de difusión de Kirby-Bauer y producción de Stx por ensayo de citotoxicidad específica en células Vero. Se aisló E. coli O157:H7 en una sola muestra de carne picada fresca (2,7% caracterizada como gen eae (+/stx2/EHEC-hlyA.Escherichia coli O157:H7 is an emergent pathogen associated with food transmitted diseases. In 1982, Escherichia coli 0157:H7 was for the first time identified as the cause of two hemorrhagic colitis outbreaks in the United States. It is now well known that most cases of hemolytic uremic syndrome are caused by these bacteria. The objective of this work was to detect the microorganism in fresh ground beef and hamburgers. From April 2003 to August 2004 samples were taken at sale

Saltelli Global Sensitivity Analysis and Simulation Modelling to Identify Intervention Strategies to Reduce the Prevalence of Escherichia coli O157 Contaminated Beef Carcasses.

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Victoria J Brookes

Full Text Available Strains of Shiga-toxin producing Escherichia coli O157 (STEC O157 are important foodborne pathogens in humans, and outbreaks of illness have been associated with consumption of undercooked beef. Here, we determine the most effective intervention strategies to reduce the prevalence of STEC O157 contaminated beef carcasses using a modelling approach.A computational model simulated events and processes in the beef harvest chain. Information from empirical studies was used to parameterise the model. Variance-based global sensitivity analysis (GSA using the Saltelli method identified variables with the greatest influence on the prevalence of STEC O157 contaminated carcasses. Following a baseline scenario (no interventions, a series of simulations systematically introduced and tested interventions based on influential variables identified by repeated Saltelli GSA, to determine the most effective intervention strategy.Transfer of STEC O157 from hide or gastro-intestinal tract to carcass (improved abattoir hygiene had the greatest influence on the prevalence of contaminated carcases. Due to interactions between inputs (identified by Saltelli GSA, combinations of interventions based on improved abattoir hygiene achieved a greater reduction in maximum prevalence than would be expected from an additive effect of single interventions. The most effective combination was improved abattoir hygiene with vaccination, which achieved a greater than ten-fold decrease in maximum prevalence compared to the baseline scenario.Study results suggest that effective interventions to reduce the prevalence of STEC O157 contaminated carcasses should initially be based on improved abattoir hygiene. However, the effect of improved abattoir hygiene on the distribution of STEC O157 concentration on carcasses is an important information gap-further empirical research is required to determine whether reduced prevalence of contaminated carcasses is likely to result in reduced

Inactivation of Escherichia coli O157:H7 in biofilm on food-contact surfaces by sequential treatments of aqueous chlorine dioxide and drying.

Science.gov (United States)

Bang, Jihyun; Hong, Ayoung; Kim, Hoikyung; Beuchat, Larry R; Rhee, Min Suk; Kim, Younghoon; Ryu, Jee-Hoon

2014-11-17

We investigated the efficacy of sequential treatments of aqueous chlorine and chlorine dioxide and drying in killing Escherichia coli O157:H7 in biofilms formed on stainless steel, glass, plastic, and wooden surfaces. Cells attached to and formed a biofilm on wooden surfaces at significantly (P ≤ 0.05) higher levels compared with other surface types. The lethal activities of sodium hypochlorite (NaOCl) and aqueous chlorine dioxide (ClO₂) against E. coli O157:H7 in a biofilm on various food-contact surfaces were compared. Chlorine dioxide generally showed greater lethal activity than NaOCl against E. coli O157:H7 in a biofilm on the same type of surface. The resistance of E. coli O157:H7 to both sanitizers increased in the order of wood>plastic>glass>stainless steel. The synergistic lethal effects of sequential ClO₂ and drying treatments on E. coli O157:H7 in a biofilm on wooden surfaces were evaluated. When wooden surfaces harboring E. coli O157:H7 biofilm were treated with ClO₂ (200 μg/ml, 10 min), rinsed with water, and subsequently dried at 43% relative humidity and 22 °C, the number of E. coli O157:H7 on the surface decreased by an additional 6.4 CFU/coupon within 6 h of drying. However, when the wooden surface was treated with water or NaOCl and dried under the same conditions, the pathogen decreased by only 0.4 or 1.0 log CFU/coupon, respectively, after 12 h of drying. This indicates that ClO₂ treatment of food-contact surfaces results in residual lethality to E. coli O157:H7 during the drying process. These observations will be useful when selecting an appropriate type of food-contact surfaces, determining a proper sanitizer for decontamination, and designing an effective sanitization program to eliminate E. coli O157:H7 on food-contact surfaces in food processing, distribution, and preparation environments. Copyright © 2014 Elsevier B.V. All rights reserved.

Acceptance test report for project C-157 ''T-Plant electrical upgrade''

International Nuclear Information System (INIS)

Jeppson, L.A.

1997-01-01

This Acceptance Test Report (ATR) documents for record purposes the field results, acceptance, and approvals of the completed acceptance test per WHC-SD-Cl57-ATP-001, Rev. 0, ''Acceptance Test Proceedure for Project C-157 'T Plant Electrical Upgrade''' The test was completed and approved without any problems or exceptions

Acceptance test report for project C-157 ``T-Plant electrical upgrade``

Energy Technology Data Exchange (ETDEWEB)

Jeppson, L.A.

1997-08-05

This Acceptance Test Report (ATR) documents for record purposes the field results, acceptance, and approvals of the completed acceptance test per WHC-SD-Cl57-ATP-001, Rev. 0, ``Acceptance Test Proceedure for Project C-157 `T Plant Electrical Upgrade``` The test was completed and approved without any problems or exceptions.

Sensitive detection of viable Escherichia coli O157:H7 from foods using a luciferase-reporter phage phiV10lux.

Science.gov (United States)

Kim, Jinwoo; Kim, Minsik; Kim, Seongmi; Ryu, Sangryeol

2017-08-02

Escherichia coli O157:H7, a major foodborne pathogen, is a major public health concern associated with life-threatening diseases such as hemolytic uremic syndrome. To alleviate this burden, a sensitive and rapid system is required to detect this pathogen in various kinds of foods. Herein, we propose a phage-based pathogen detection method to replace laborious and time-consuming conventional methods. We engineered an E. coli O157:H7-specific phage phiV10 to rapidly and sensitively detect this notorious pathogen. The luxCDABE operon was introduced into the phiV10 genome and allowed the engineered phage phiV10lux to generate bioluminescence proportional to the number of viable E. coli O157:H7 cells without any substrate addition. The phage phiV10lux was able to detect at least 1CFU/ml of E. coli O157:H7 in a pure culture within 40min after 5h of pre-incubation. In artificially contaminated romaine lettuce, apple juice (pH3.51), and ground beef, the reporter phage could detect approximately 10CFU/cm 2 , 13CFU/ml, and 17CFU/g of E. coli O157:H7, respectively. Taken together, the constructed reporter phage phiV10lux could be applied as a powerful tool for rapid and sensitive detection of live E. coli O157:H7 in foods. Copyright © 2017 Elsevier B.V. All rights reserved.

Utilization of evolutionary model, bioinformatics and heuristics for development of a multiplex Escherichia coli O157:H7 PCR assay

Science.gov (United States)

Introduction: Escherichia coli O157:H7 is a devastating foodborne pathogen causing many foodborne outbreaks worldwide with significant morbidity and mortality. The plasticity of the E. coli O157:H7 genome, inconsistent expression of surface antigens, and sharing of genetic elements with other non-...

Prevalence and antibiogram profiles of Escherichia coli O157:H7 isolates recovered from three selected dairy farms in the Eastern Cape Province, South Africa

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Luyanda Msolo

2016-12-01

Full Text Available Objective: To investigate the occurrence and antibiotics susceptibility of Escherichia coli (E. coli O157:H7 isolates from raw milk, cattle udder, milking machines and worker’s hand swabs from three selected commercial dairy farms in the Amathole District Municipality, Eastern Cape Province, South Africa. Methods: Raw milk samples were collected from bulk storage tanks and swab samples were collected from milking machines, cattle udders and worker’s hands fortnightly over a sixmonth sampling regime between June and November 2014. A standard culture-based method was used for the enumeration and isolation of E. coli O157:H7, presumptive identification using sorbitol MacConkey agar (supplemented with cefixime (50 µg/L and potassium tellurite (25 mg/L. A serological confirmation of the presumptive E. coli O157:H7 isolates was conducted using the O157 latex agglutination test kit. Results: A total of 252 E. coli O157:H7 isolates were further subjected to PCR amplification of rfbEO157 and flCH7 genes of which 27(11% of the isolates were confirmed positive E. coli O157:H7. The percentage antibiotic resistance of the 27 E. coli O157:H7 isolates from the dairy farms revealed penicillin [23 (85%], tetracycline [22 (81%], erythromycin [19 (70%], streptomycin [14 (52%] and chloramphenicol [12 (45%]. The highest resistances were penicillin [23 (85%] and tetracycline [22 (81%]. Conclusions: These findings revealed that the dairy farms are potential reservoirs of E. coli O157:H7 serotype, and harbor antibiotic-resistant determinants, a concern to public and environmental health.

Inactivation of E-coli O157 : H7 in apple cider by ozone at various temperatures and concentrations

DEFF Research Database (Denmark)

Steenstrup, Lotte Dock

2004-01-01

of dissolved ozone of about 5-6 mg/L at 20C, before the on-set of E. coli O157:H7 inactivation in the cider. Total processing times, based on lag time plus 5D, ranged from about 4 to 14 min depending on temperature and ozone concentration. Overall, inactivation of E. coli O157:H7by ozone was fast enough...

DNA fingerprinting of Shiga-toxin producing Escherichia coli O157 based on Multiple-Locus Variable-Number Tandem-Repeats Analysis (MLVA

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Vardund Traute

2003-12-01

Full Text Available Abstract Background The ability to react early to possible outbreaks of Escherichia coli O157:H7 and to trace possible sources relies on the availability of highly discriminatory and reliable techniques. The development of methods that are fast and has the potential for complete automation is needed for this important pathogen. Methods In all 73 isolates of shiga-toxin producing E. coli O157 (STEC were used in this study. The two available fully sequenced STEC genomes were scanned for tandem repeated stretches of DNA, which were evaluated as polymorphic markers for isolate identification. Results The 73 E. coli isolates displayed 47 distinct patterns and the MLVA assay was capable of high discrimination between the E. coli O157 strains. The assay was fast and all the steps can be automated. Conclusion The findings demonstrate a novel high discriminatory molecular typing method for the important pathogen E. coli O157 that is fast, robust and offers many advantages compared to current methods.

10C survey of radio sources at 15.7 GHz - II. First results

Science.gov (United States)

AMI Consortium; Davies, Mathhew L.; Franzen, Thomas M. O.; Waldram, Elizabeth M.; Grainge, Keith J. B.; Hobson, Michael P.; Hurley-Walker, Natasha; Lasenby, Anthony; Olamaie, Malak; Pooley, Guy G.; Riley, Julia M.; Rodríguez-Gonzálvez, Carmen; Saunders, Richard D. E.; Scaife, Anna M. M.; Schammel, Michel P.; Scott, Paul F.; Shimwell, Timothy W.; Titterington, David J.; Zwart, Jonathan T. L.

2011-08-01

In a previous paper (Paper I), the observational, mapping and source-extraction techniques used for the Tenth Cambridge (10C) Survey of Radio Sources were described. Here, the first results from the survey, carried out using the Arcminute Microkelvin Imager Large Array (LA) at an observing frequency of 15.7 GHz, are presented. The survey fields cover an area of ≈27 deg2 to a flux-density completeness of 1 mJy. Results for some deeper areas, covering ≈12 deg2, wholly contained within the total areas and complete to 0.5 mJy, are also presented. The completeness for both areas is estimated to be at least 93 per cent. The 10C survey is the deepest radio survey of any significant extent (≳0.2 deg2) above 1.4 GHz. The 10C source catalogue contains 1897 entries and is available online. The source catalogue has been combined with that of the Ninth Cambridge Survey to calculate the 15.7-GHz source counts. A broken power law is found to provide a good parametrization of the differential count between 0.5 mJy and 1 Jy. The measured source count has been compared with that predicted by de Zotti et al. - the model is found to display good agreement with the data at the highest flux densities. However, over the entire flux-density range of the measured count (0.5 mJy to 1 Jy), the model is found to underpredict the integrated count by ≈30 per cent. Entries from the source catalogue have been matched with those contained in the catalogues of the NRAO VLA Sky Survey and the Faint Images of the Radio Sky at Twenty-cm survey (both of which have observing frequencies of 1.4 GHz). This matching provides evidence for a shift in the typical 1.4-GHz spectral index to 15.7-GHz spectral index of the 15.7-GHz-selected source population with decreasing flux density towards sub-mJy levels - the spectra tend to become less steep. Automated methods for detecting extended sources, developed in Paper I, have been applied to the data; ≈5 per cent of the sources are found to be extended

ANALISIS MIKROBIOLOGI ESCHERICHIA COLI O157:H7 PADA HASIL OLAHAN HEWAN SAPI DALAM PROSES PRODUKSINYA

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Trini Sudiarti

2005-06-01

Full Text Available Microbiological analysis of Escherichia coli O157:H7 on Cow’s Products during the Production Process. The problem on food health is the high amount of bacterial contamination of food served by several kinds of food sellers, e.g. vendors, restaurants, caterers and food industries. Meat and milk products are kinds of food prone to contamination. To secure food against contamination by bacteria such as E. coli O157:H7, especially related to raw food, should beginwith the securing of products through the whole production process till it reaches the consumers. Although these pathogenic bacteria are part of the normal flora in the intestines of cattle, however we should be aware of the possibility of an outbreak in the community due to E. coli O157:H7 contamination of beef products. To anticipate the danger of an outbreak a study should be conducted to know about this microorganism from the beginning i.e. the production phaseuntil the seller phase. The aim of this research is to know the existence of E. coli O157:H7 on beef and milk products obtained from abattoirs, cow ranches, traditional markets and other sellers in addition with knowing the influencing factors on the spreading of the microorganism. The survey design used for this research is the cross sectional design. The material used for the tests are 250 ml water/milk and 250 gram beef/carcass. The bacterial tests included qualitative tests as follows: presumptive test, confirmed test, completed test, whereas quantitatively tests as follows: Total PlateCound (TPC, Most Probable Number (MPN, which is a near amount prediction of bacteria per 100 ml of water. Results showed that all meat (100% coming from abattoirs and traditional markets were contaminated with E. coli O157:H7, in addition with most of the fresh and pasteurized milk samples (73.3% coming from cattle ranches and home industries. Contamination was also found in most of the water samples (60% and in food handlers (41.7%.

Association Study between the CD157/BST1 Gene and Autism Spectrum Disorders in a Japanese Population

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Shigeru Yokoyama

2015-05-01

Full Text Available CD157, also referred to as bone marrow stromal cell antigen-1 (BST-1, is a glycosylphosphatidylinositol-anchored molecule that promotes pre-B-cell growth. Previous studies have reported associations between single-nucleotide polymorphisms (SNPs of the CD157/BST1 gene with Parkinson’s disease. In an attempt to determine whether SNPs or haplotypes in the CD157/BST1 are associated with other brain disorders, we performed a case-control study including 147 autism spectrum disorder (ASD patients at Kanazawa University Hospital in Japan and 150 unselected Japanese volunteers by the sequence-specific primer-polymerase chain reaction method combined with fluorescence correlation spectroscopy. Of 93 SNPs examined, two SNPs showed significantly higher allele frequencies in cases with ASDs than in unaffected controls (rs4301112, OR = 6.4, 95% CI = 1.9 to 22, p = 0.0007; and rs28532698, OR = 6.2, 95% CI = 1.8 to 21, p = 0.0012; Fisher’s exact test; p < 0.002 was considered significant after multiple testing correction. In addition, CT genotype in rs10001565 was more frequently observed in the ASD group than in the control group (OR = 15, 95% CI = 2.0 to 117, p = 0.0007; Fisher’s exact test. The present data indicate that genetic variation of the CD157/BST1 gene might confer susceptibility to ASDs.

Changes in the bacterial number (enterohaemorrhagic E. coli O157:H7, coliforms and SPC) in salted vegetables during storage and by treatment with electron-beam irradiation

International Nuclear Information System (INIS)

Miyahara, Michiko; Miyahara, Makoto

2007-01-01

Enterohaemorrhagic Escherichia coli O157:H7 causes severe illness in humans, especially young children and elder people. Some 2-3% salted vegetables (called Asazuke) contaminated with E. coli O157:H7 have caused food-poisoning and even death. The viability of E. coli O157:H7 in saline water and in salted vegetables was tested. During cold and frozen storage, the apparent decrease in the number of E. coli O157:H7 was not observed. However, electron-beam irradiation (0.534, 1.097 and 2.639 kGy) caused clear decrease in the numbers of E. coli O157:H7 in frozen salted Mizuna. The number of standard plating count (SPC) and coliforms were also counted and compared with the changes in the number of E. coli O157:H7. (author)

An outbreak of Vero cytotoxin producing Escherichia coli O157 infection associated with takeaway sandwiches.

LENUS (Irish Health Repository)

McDonnell, R J

1997-12-12

An outbreak of food poisoning due to Escherichia coli O157 phage type 2 Vero cytotoxin 2 affected 26 people in southern counties of England in May and June 1995. The organism was isolated from faecal specimens from 23 patients, 16 of whom lived in Dorset and seven in Hampshire. Isolates were indistinguishable by phage typing, Vero cytotoxin gene typing, restriction fragment length polymorphism, and pulsed field gel electrophoresis. Three associated cases, linked epidemiologically to the outbreak, were confirmed serologically by detection of antibodies to E. coli O157 lipopolysaccharide. Twenty-two of the 26 patients were adults: four were admitted to hospital with haemorrhagic colitis. Four cases were children: two were admitted to hospital with haemolytic uraemic syndrome (HUS). There were no deaths. Although E. coli O157 was not isolated from any food samples, illness was associated with having eaten cold meats in sandwiches bought from two sandwich producers, in Weymouth and in Portsmouth. Both shops were supplied by the same wholesaler, who kept no records and obtained cooked meats from several sources in packs that did not carry adequate identification marks. It was, therefore, impossible to trace back to the original producer or to investigate further to determine the origin of contamination with E. coli O157. To protect the public health it is essential that all wholesale packs of ready-to-eat food carry date codes and the producer\\'s identification mark. Detailed record keeping should be part of hazard analysis critical control point (HACCP) systems and should be maintained throughout the chain of distribution from the producer to retail outlets.

Foodborne transmission of sorbitol-fermenting Escherichia coli O157:[H7] via ground beef: an outbreak in northern France, 2011.

Science.gov (United States)

King, L A; Loukiadis, E; Mariani-Kurkdjian, P; Haeghebaert, S; Weill, F-X; Baliere, C; Ganet, S; Gouali, M; Vaillant, V; Pihier, N; Callon, H; Novo, R; Gaillot, O; Thevenot-Sergentet, D; Bingen, E; Chaud, P; de Valk, H

2014-12-01

Sorbitol-fermenting Escherichia coli O157:[H7] is a particularly virulent clone of E. coli O157:H7 associated with a higher incidence of haemolytic uraemic syndrome and a higher case fatality rate. Many fundamental aspects of its epidemiology remain to be elucidated, including its reservoir and transmission routes and vehicles. We describe an outbreak of sorbitol-fermenting E. coli O157:[H7] that occurred in France in 2011. Eighteen cases of paediatric haemolytic uraemic syndrome with symptom onset between 6 June and 15 July 2011 were identified among children aged 6 months to 10 years residing in northern France. A strain of sorbitol-fermenting E. coli O157:[H7] stx2a eae was isolated from ten cases. Epidemiological, microbiological and trace-back investigations identified multiply-contaminated frozen ground beef products bought in a supermarket chain as the outbreak vehicle. Strains with three distinct pulsotypes that were isolated from patients, ground beef preparations recovered from patients' freezers and from stored production samples taken at the production plant were indistinguishable upon molecular comparison. This investigation documents microbiologically confirmed foodborne transmission of sorbitol-fermenting of E. coli O157 via beef and could additionally provide evidence of a reservoir in cattle for this pathogen. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

Roles of individual radicals generated by a submerged dielectric barrier discharge plasma reactor during Escherichia coli O157:H7 inactivation

Energy Technology Data Exchange (ETDEWEB)

Khan, Muhammad Saiful Islam [Department of Food Biotechnology, University of Science and Technology, Daejeon, 305-350 (Korea, Republic of); Lee, Eun-Jung [Food Safety Research Group, Korea Food Research Institute, Seongnam-si, Gyeonggi-Do (Korea, Republic of); Kim, Yun-Ji, E-mail: yunji@kfri.re.kr [Department of Food Biotechnology, University of Science and Technology, Daejeon, 305-350 (Korea, Republic of); Food Safety Research Group, Korea Food Research Institute, Seongnam-si, Gyeonggi-Do (Korea, Republic of)

2015-10-15

A submerged dielectric barrier discharge plasma reactor (underwater DBD) has been used on Escherichia coli O157:H7 (ATCC 35150). Plasma treatment was carried out using clean dry air gas to investigate the individual effects of the radicals produced by underwater DBD on an E. coli O157:H7 suspension (8.0 log CFU/ml). E. coli O157:H7 was reduced by 6.0 log CFU/ml for 2 min of underwater DBD plasma treatment. Optical Emission Spectra (OES) shows that OH and NO (α, β) radicals, generated by underwater DBD along with ozone gas. E. coli O157:H7 were reduced by 2.3 log CFU/ml for 10 min of underwater DBD plasma treatment with the terephthalic acid (TA) OH radical scavenger solution, which is significantly lower (3.7 log CFU/ml) than the result obtained without using the OH radical scavenger. A maximum of 1.5 ppm of ozone gas was produced during the discharge of underwater DBD, and the obtained reduction difference in E.coli O157:H7 in presence and in absence of ozone gas was 1.68 log CFU/ml. The remainder of the 0.62 log CFU/ml reduction might be due to the effect of the NO (α, β) radicals or due to the combined effect of all the radicals produced by underwater DBD. A small amount of hydrogen peroxide was also generated but does not play any role in E. coli O157:H7 inactivation.

Genomic Variability of O Islands Encoding Tellurite Resistance in Enterohemorrhagic Escherichia coli O157:H7 Isolates

OpenAIRE

Taylor, Diane E.; Rooker, Michelle; Keelan, Monika; Ng, Lai-King; Martin, Irene; Perna, Nicole T.; Burland, N. T. Valerie; Blattner, Fredrick R.

2002-01-01

Strains of Escherichia coli causing enterohemorrhagic colitis belonging to the O157:H7 lineage are reported to be highly related. Fifteen strains of E. coli O157:H7 and 1 strain of E. coli O46:H− (nonflagellated) were examined for the presence of potassium tellurite resistance (Ter). Ter genes comprising terABCDEF were shown previously to be part of a pathogenicity island also containing integrase, phage, and urease genes. PCR analysis, both conventional and light cycler based, demonstrated t...

FimH has a strain and host-cell type dependent role in adherence of E. coli O157:H7 super-shedder strains to host cells

Science.gov (United States)

Escherichia coli O157:H7 (O157) are Shiga toxin-producing food-borne pathogens that are a significant threat to human health, causing severe illnesses including hemorrhagic uremic syndrome and kidney failure. Cattle are the major reservoirs of O157, with asymptomatic animals harboring the organism i...

In silico genomic analyses reveal three distinct lineages of Escherichia coli O157:H7, one of which is associated with hyper-virulence.

Science.gov (United States)

Laing, Chad R; Buchanan, Cody; Taboada, Eduardo N; Zhang, Yongxiang; Karmali, Mohamed A; Thomas, James E; Gannon, Victor Pj

2009-06-29

Many approaches have been used to study the evolution, population structure and genetic diversity of Escherichia coli O157:H7; however, observations made with different genotyping systems are not easily relatable to each other. Three genetic lineages of E. coli O157:H7 designated I, II and I/II have been identified using octamer-based genome scanning and microarray comparative genomic hybridization (mCGH). Each lineage contains significant phenotypic differences, with lineage I strains being the most commonly associated with human infections. Similarly, a clade of hyper-virulent O157:H7 strains implicated in the 2006 spinach and lettuce outbreaks has been defined using single-nucleotide polymorphism (SNP) typing. In this study an in silico comparison of six different genotyping approaches was performed on 19 E. coli genome sequences from 17 O157:H7 strains and single O145:NM and K12 MG1655 strains to provide an overall picture of diversity of the E. coli O157:H7 population, and to compare genotyping methods for O157:H7 strains. In silico determination of lineage, Shiga-toxin bacteriophage integration site, comparative genomic fingerprint, mCGH profile, novel region distribution profile, SNP type and multi-locus variable number tandem repeat analysis type was performed and a supernetwork based on the combination of these methods was produced. This supernetwork showed three distinct clusters of strains that were O157:H7 lineage-specific, with the SNP-based hyper-virulent clade 8 synonymous with O157:H7 lineage I/II. Lineage I/II/clade 8 strains clustered closest on the supernetwork to E. coli K12 and E. coli O55:H7, O145:NM and sorbitol-fermenting O157 strains. The results of this study highlight the similarities in relationships derived from multi-locus genome sampling methods and suggest a "common genotyping language" may be devised for population genetics and epidemiological studies. Future genotyping methods should provide data that can be stored centrally and

In silico genomic analyses reveal three distinct lineages of Escherichia coli O157:H7, one of which is associated with hyper-virulence

Directory of Open Access Journals (Sweden)

Karmali Mohamed A

2009-06-01

Full Text Available Abstract Background Many approaches have been used to study the evolution, population structure and genetic diversity of Escherichia coli O157:H7; however, observations made with different genotyping systems are not easily relatable to each other. Three genetic lineages of E. coli O157:H7 designated I, II and I/II have been identified using octamer-based genome scanning and microarray comparative genomic hybridization (mCGH. Each lineage contains significant phenotypic differences, with lineage I strains being the most commonly associated with human infections. Similarly, a clade of hyper-virulent O157:H7 strains implicated in the 2006 spinach and lettuce outbreaks has been defined using single-nucleotide polymorphism (SNP typing. In this study an in silico comparison of six different genotyping approaches was performed on 19 E. coli genome sequences from 17 O157:H7 strains and single O145:NM and K12 MG1655 strains to provide an overall picture of diversity of the E. coli O157:H7 population, and to compare genotyping methods for O157:H7 strains. Results In silico determination of lineage, Shiga-toxin bacteriophage integration site, comparative genomic fingerprint, mCGH profile, novel region distribution profile, SNP type and multi-locus variable number tandem repeat analysis type was performed and a supernetwork based on the combination of these methods was produced. This supernetwork showed three distinct clusters of strains that were O157:H7 lineage-specific, with the SNP-based hyper-virulent clade 8 synonymous with O157:H7 lineage I/II. Lineage I/II/clade 8 strains clustered closest on the supernetwork to E. coli K12 and E. coli O55:H7, O145:NM and sorbitol-fermenting O157 strains. Conclusion The results of this study highlight the similarities in relationships derived from multi-locus genome sampling methods and suggest a "common genotyping language" may be devised for population genetics and epidemiological studies. Future genotyping

Effect of caliber size and fat level on the inactivation of E. coli O157:H7 in dry fermented sausages.

Science.gov (United States)

De Souza, James; Ahmed, Rafath; Strange, Philip; Barbut, Shai; Balamurugan, S

2018-02-02

Dry fermented sausages (DFS) have been subject to numerous validation studies, as pathogen reduction heavily relies on both ingredients and processing. In this study the effect of product caliber size (32, 55, 80mm), and fat level (low, 9.67%; high, 18.46% wt/wt) on the inactivation of E. coli O157:H7 during DFS production was examined. Sausages containing a five-strain cocktail of E. coli O157:H7 at 10 7 CFU/g were manufactured and monitored for changes in physicochemical properties and inoculated E. coli O157:H7 numbers were enumerated during the DFS production stages and log reduction rates were calculated. Significant (P0.05) different among sausages of different caliber size or fat levels. No significant (P>0.05) reduction in a w was observed during fermentation of the sausages. However, during the drying phase, sausages with larger caliber sizes required a significantly longer duration of drying to achieve the same a w of smaller caliber size sausages. For instance, to achieve an a w of ≤0.9, following 5days of fermentation/curing, 80mm caliber sausages required up to 27days of drying compared with 13 and 6days for 55 and 32mm caliber size sausages, respectively. Fat levels on the other hand did not significantly (P>0.05) effect the reduction of a w during drying of the sausages. During the fermentation stage there was a significant and rapid reduction in E. coli O157:H7 counts by about 1.1- to 1.4-log units, but was not significantly different among sausages of different caliber size and fat levels. Considering the whole process, only caliber size had a significant effect on log reduction of E. coli O157:H7. ANOVA of log reduction rates of E. coli O157:H7 among sausages of different caliber size and fat levels revealed no significant differences during the fermentation, however, during the drying of the sausages, log reduction rate of E. coli O157:H7 was significantly (PE. coli O157:H7 in high fat large caliber sausages was the lowest at -0.082±0.004 log

Efficacy of (+-Lariciresinol to Control Bacterial Growth of Staphylococcus aureus and Escherichia coli O157:H7

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Vivek K. Bajpai

2017-05-01

Full Text Available This study was undertaken to assess the antibacterial potential of a polyphenolic compound (+-lariciresinol isolated from Rubia philippinensis against selected foodborne pathogens Staphylococcus aureus KCTC1621 and Escherichia coli O157:H7. (+-Lariciresinol at the tested concentrations (250 μg/disk evoked a significant antibacterial effect as a diameter of inhibition zones (12.1–14.9 mm with minimum inhibitory concentration (MIC, and minimum bactericidal concentration values of 125–250 and 125–250 μg/mL, respectively. Furthermore, (+-lariciresinol at MIC showed reduction in bacterial cell viabilities, efflux of potassium (K+ ions and release of 260 nm materials against E. coli O157:H7 and S. aureus KCTC1621. Moreover, deteriorated cell wall morphology of E. coli O157:H7 and S. aureus KCTC1621 cells treated with (+-lariciresinol at MIC further confirmed its inhibitory effect against the tested pathogens, suggesting it to be an alternative means of antimicrobials.

Effectiveness of Active Packaging on Control of Escherichia Coli O157:H7 and Total Aerobic Bacteria on Iceberg Lettuce.

Science.gov (United States)

Lu, Haixia; Zhu, Junli; Li, Jianrong; Chen, Jinru

2015-06-01

Contaminated leafy green vegetables have been linked to several outbreaks of human gastrointestinal infections. Antimicrobial interventions that are adoptable by the fresh produce industry for control of pathogen contamination are in great demand. This study was undertaken to evaluate the efficacy of sustained active packaging on control of Escherichia coli O157:H7 and total aerobic bacteria on lettuce. Commercial Iceberg lettuce was inoculated with a 3-strain mixture of E. coli O157:H7 at 10(2) or 10(4) CFU/g. The contaminated lettuce and un-inoculated controls were placed respectively in 5 different active packaging structures. Traditional, nonactive packaging structure was included as controls. Packaged lettuce was stored at 4, 10, or 22 °C for 3 wk and sampled weekly for the population of E. coli O157:H7 and total aerobic bacteria. Results showed that packaging structures with ClO2 generator, CO2 generator, or one of the O2 scavengers effectively controlled the growth of E. coli O157:H7 and total aerobic bacteria under all storage conditions. Packaging structure with the ClO2 generator was most effective and no E. coli O157:H7 was detected in samples packaged in this structure except for those that were inoculated with 4 log CFU/g of E. coli O157:H7 and stored at 22 °C. Packaging structures with an oxygen scavenger and the allyl isothiocyanate generator were mostly ineffective in control of the growth of the bacteria on Iceberg lettuce. The research suggests that some of the packaging structures evaluated in the study can be used to control the presence of foodborne pathogens on leafy green vegetables. © 2015 Institute of Food Technologists®

Quantitative transfer of Escherichia coli O157:H7 to equipment during small-scale production of fresh-cut leafy greens.

Science.gov (United States)

Buchholz, Annemarie L; Davidson, Gordon R; Marks, Bradley P; Todd, Ewen C D; Ryser, Elliot T

2012-07-01

Postharvest contamination and subsequent spread of Escherichia coli O157:H7 can occur during shredding, conveying, fluming, and dewatering of fresh-cut leafy greens. This study quantified E. coli O157:H7 transfer from leafy greens to equipment surfaces during simulated small-scale commercial processing. Three to five batches (22.7 kg) of baby spinach, iceberg lettuce, and romaine lettuce were dip inoculated with a four-strain cocktail of avirulent, green fluorescent protein-labeled, ampicillinresistant E. coli O157:H7 to contain ∼10(6), 10(4), and 10(2) CFU/g, and then were processed after 1 h of draining at ∼23°C or 24 h of storage at 4°C. Lettuce was shredded using an Urschel TransSlicer at two different blade and belt speeds to obtain normal (5 by 5 cm) and more finely shredded (0.5 by 5 cm) lettuce. Thereafter, the lettuce was step conveyed to a flume tank and was washed and then dried using a shaker table and centrifugal dryer. Product (25-g) and water (40-ml) samples were collected at various points during processing. After processing, product contact surfaces (100 cm(2)) on the shredder (n = 14), conveyer (n = 8), flume tank (n = 11), shaker table (n = 9), and centrifugal dryer (n = 8) were sampled using one-ply composite tissues. Sample homogenates diluted in phosphate or neutralizing buffer were plated, with or without prior 0.45- m m membrane filtration, on Trypticase soy agar containing 0.6% yeast extract supplemented with 100 ppm of ampicillin to quantify green fluorescent protein-labeled E. coli O157:H7 under UV light. During leafy green processing, ∼90% of the E. coli O157:H7 inoculum transferred to the wash water. After processing, E. coli O157:H7 populations were highest on the conveyor and shredder (Ptransfer.

Helium Bubbles Cavitation Phenomena in Pb-15.7Li and Potential Impact on Tritium Transport Behaviour in HCLL Breeding Channels

International Nuclear Information System (INIS)

Sedano, L. A.

2007-01-01

COMPU task is devoted to develop a Process Flow Diagram (PFD) modelling tool for DEMO tritium cycle for HCLL and HCPB blanket lines for DEMO. At the actual stage of definition of HCLL blanket design line this global objective requires to progress specifically on the physical reliability of tritium transport assessments at blanket design level. A rough reliability assessment with the identify cation of physical phenomena determining permeation rates into the coolant was tentatively advanced in COMPU Task Deliverable 1. In HCLL design, the tritium diffusion in the alloy under the flow conditions and radiation effects in Pb15.7Li can be theoretically justifies ed as the rate limiting processes for tritium transfer into the coolant. This Deliverable 2 focuses on the analysis of a specific radiation effect: the potential role of helium bubbles in Pb15.7Li, the discussion of its implications on tritium assessment for HCLL design and consequently the analysis of its quantitative impact (as cycle input) on HCLL PFD tritium cycle design. Thus, the contents of this report investigate: (1) the rationality of the consideration on HCLL design of helium bubble cavitation phenomena in irradiated Pb15.7Li channels on the base of fundamental analysis (He solution states in Pb15.7Li) from empirical clues provided by Pb15.7Li irradiation tests, (2) a preliminary rough He-bubble cavitation design assessment and bases for a more precise FEM calculation for helium bubble cavitation phenomena in HCLL blanket channels, (3) the analysis of direct experimental data and numerical developments needed for a precise cavitation assessment and (4) a proposal of the lay-out and general specifications of an integral proof-of-principle Cavitation Experiment (Cevitex) of Helium in Pb15.7Li. (Author) 40 refs

Helium Bubbles Cavitation Phenomena in Pb-15.7Li and Potential Impact on Tritium Transport Behaviour in HCLL Breeding Channels

Energy Technology Data Exchange (ETDEWEB)

Sedano, L. A.

2007-09-27

COMPU task is devoted to develop a Process Flow Diagram (PFD) modelling tool for DEMO tritium cycle for HCLL and HCPB blanket lines for DEMO. At the actual stage of definition of HCLL blanket design line this global objective requires to progress specifically on the physical reliability of tritium transport assessments at blanket design level. A rough reliability assessment with the identify cation of physical phenomena determining permeation rates into the coolant was tentatively advanced in COMPU Task Deliverable 1. In HCLL design, the tritium diffusion in the alloy under the flow conditions and radiation effects in Pb15.7Li can be theoretically justifies ed as the rate limiting processes for tritium transfer into the coolant. This Deliverable 2 focuses on the analysis of a specific radiation effect: the potential role of helium bubbles in Pb15.7Li, the discussion of its implications on tritium assessment for HCLL design and consequently the analysis of its quantitative impact (as cycle input) on HCLL PFD tritium cycle design. Thus, the contents of this report investigate: (1) the rationality of the consideration on HCLL design of helium bubble cavitation phenomena in irradiated Pb15.7Li channels on the base of fundamental analysis (He solution states in Pb15.7Li) from empirical clues provided by Pb15.7Li irradiation tests, (2) a preliminary rough He-bubble cavitation design assessment and bases for a more precise FEM calculation for helium bubble cavitation phenomena in HCLL blanket channels, (3) the analysis of direct experimental data and numerical developments needed for a precise cavitation assessment and (4) a proposal of the lay-out and general specifications of an integral proof-of-principle Cavitation Experiment (Cevitex) of Helium in Pb15.7Li. (Author) 40 refs.

Co-ordinate single-cell expression of LEE4- and LEE5-encoded proteins of Escherichia coli O157:H7.

Science.gov (United States)

Roe, Andrew J; Naylor, Stuart W; Spears, Kevin J; Yull, Helen M; Dransfield, Tracy A; Oxford, Matthew; McKendrick, Iain J; Porter, Megan; Woodward, Martin J; Smith, David G E; Gally, David L

2004-10-01

Escherichia coli O157:H7 is a zoonotic pathogen that can express a type III secretion system (TTSS) considered important for colonization and persistence in ruminants. E. coli O157:H7 strains have been shown to vary markedly in levels of protein secreted using the TTSS and this study has confirmed that a high secretion phenotype is more prevalent among isolates associated with human disease than isolates shed by healthy cattle. The variation in secretion levels is a consequence of heterogeneous expression, being dependent on the proportion of bacteria in a population that are actively engaged in protein secretion. This was demonstrated by indirect immunofluorescence and eGFP fusions that examined the expression of locus of enterocyte effacement (LEE)-encoded factors in individual bacteria. In liquid media, the expression of EspA, tir::egfp, intimin, but not map::egfp were co-ordinated in a subpopulation of bacteria. In contrast to E. coli O157:H7, expression of tir::egfp in EPEC E2348/69 was equivalent in all bacteria although the same fusion exhibited variable expression when transformed into an E. coli O157:H7 background. An E. coli O157:H7 strain deleted for the LEE demonstrated weak but variable expression of tir::egfp indicating that the elements controlling the heterogeneous expression lie outside the LEE. The research also demonstrated the rapid induction of tir::egfp and map::egfp on contact with bovine epithelial cells. This control in E. coli O157:H7 may be required to limit exposure of key surface antigens, EspA, Tir and intimin during colonization of cattle but allow their rapid production on contact with bovine gastrointestinal epithelium at the terminal rectum.

Presence of Staphylococcus aureus and Shiga Toxigenic Escherichia coli O157:H7 in Raw Meat in Ağrı, Turkey

Directory of Open Access Journals (Sweden)

Naim Deniz Ayaz

2016-08-01

Full Text Available Background: Staphylococcus aureus and Shiga toxin producing Escherichia coli O157:H7 (EHEC are significant foodborne pathogens worldwide. While S. aureus can cause mild superficial skin infections or life-threatening bacteremia and endocarditis, as well as toxininduced cases such as toxic shock syndrome; E. coli O157:H7 can cause symptoms from mild diarrhea to severe hemorrhagic colitis (HC, hemolytic uremic syndrome (HUS, thrombotic thrombocytopenic purpura (TTP. Objectives: The objectives of this study were to find out the prevalence and seasonal distribution of S. aureus in 214 frozen raw meat (turkey, chicken and beef and the prevalence of E. coli O157:H7 in 70 raw beef with the characterization of the E. coli O157:H7 isolate by multiplex polymerase chain reaction (PCR. Materials and Methods: For the detection of S. aureus, a total of 214 frozen raw meat samples including 74 turkey meat, 70 chicken meat and 70 beef cuts (approximately 2 × 3 cm cubic parts; and for the detection of E. coli O157:H7, a total of 70 frozen raw beef samples that all were produced from national companies and consumed in Ağrı, Turkey were analyzed. Results: Out of 214 meat samples, 25.7 % (18/70 of the beef, 11.4 % (8/74 of the chicken meat, and 5.4 % (4/70 of the turkey meat samples were contaminated with S. aureus. Out of 70 frozen raw beef samples, only 1 (1.4% was identified as both Shiga toxin 1 and 2producing E. coli O157:H7 by the detection of stx1, stx2, eaeA, hly, and fliCh7 according to multiplex PCR analysis. Conclusion: Our findings demonstrate that occurrence frequency of S. aureus was higher in frozen raw beef than in raw chicken and turkey meat samples. Although the prevalence of E. coli O157:H7 was low in beef, the presence of virulence genes, especially toxin genesrema in a significant public health concern.

Interactions of the Hindgut Mucosa-Associated Microbiome with Its Host Regulate Shedding of Escherichia coli O157:H7 by Cattle.

Science.gov (United States)

Wang, Ou; McAllister, Tim A; Plastow, Graham; Stanford, Kim; Selinger, Brent; Guan, Le Luo

2018-01-01

Cattle are the primary carrier of Escherichia coli O157:H7, a foodborne human pathogen, and those shedding >10 4 CFU/gram of feces of E. coli O157:H7 are defined as supershedders (SS). This study investigated the rectoanal junction (RAJ) mucosa-associated microbiota and its relationship with host gene expression in SS and in cattle from which E. coli O157:H7 was not detected (nonshedders [NS]), aiming to elucidate the mechanisms involved in supershedding. In total, 14 phyla, 66 families, and 101 genera of RAJ mucosa-associated bacteria were identified and Firmicutes (61.5 ± 7.5%), Bacteroidetes (27.9 ± 6.4%), and Proteobacteria (5.5 ± 2.1%) were the predominant phyla. Differential abundance analysis of operational taxonomic units (OTUs) identified 2 OTUs unique to SS which were members of Bacteroides and Clostridium and 7 OTUs unique to NS which were members of Coprococcus , Prevotella , Clostridium , and Paludibacter Differential abundance analysis of predicted microbial functions (using PICRUSt [phylogenetic investigation of communities by reconstruction of unobserved states]) revealed that 3 pathways had higher abundance (log 2 fold change, 0.10 to 0.23) whereas 12 pathways had lower abundance (log 2 fold change, -0.36 to -0.20) in SS. In addition, we identified significant correlations between expression of 19 differentially expressed genes and the relative abundance of predicted microbial functions, including nucleic acid polymerization and carbohydrate and amino acid metabolism. Our findings suggest that differences in RAJ microbiota at both the compositional and functional levels may be associated with E. coli O157:H7 supershedding and that certain microbial groups and microbial functions may influence RAJ physiology of SS by affecting host gene expression. IMPORTANCE Cattle with fecal E. coli O157:H7 at >10 4 CFU per gram of feces have been defined as the supershedders, and they are responsible for the most of the E. coli O157:H7 spread into farm

Mathematical modeling and numerical analysis of the growth of Non-O157 shiga toxin-producing Escherichia coli in spinach leaves

Science.gov (United States)

This study was conducted to investigate the growth of non-O157 Shiga toxin-producing Escherichia coli (STEC) in spinach leaves and to develop kinetic models to describe the bacterial growth. Six serogroups of non-O157 STEC, including O26, O45, O103, O111, O121, and O145, were used in the growth stu...

Protective effects of lactoferrin chimera and bovine lactoferrin in a mouse model of enterohaemorrhagic Escherichia coli O157:H7 infection

NARCIS (Netherlands)

Flores-Villaseñor, H.; Canizalez-Román, A.; Velazquez-Roman, J.; Nazmi, K.; Bolscher, J.G.M.; Leon-Sicairos, N.

2012-01-01

Mice orally infected with enterohaemorrhagic Escherichia coli (EHEC) O157:H7 were used to evaluate the activity of bovine lactoferrin (bLF) and the synthetic peptide LFchimera. Groups of BALB/c mice inoculated intragastrically with EHEC O157:H7 showed chronic intestinal infection with the pathogen

Prevalence of Escherichia coli O157:H7 and Salmonella in camels, cattle, goats, and sheep harvested for meat in Riyadh.

Science.gov (United States)

Bosilevac, Joseph M; Gassem, Mustafa A; Al Sheddy, Ibraheem A; Almaiman, Salah A; Al-Mohizea, Ibrahim S; Alowaimer, Abdullah; Koohmaraie, Mohammad

2015-01-01

Escherichia coli O157:H7 and Salmonella are significant foodborne pathogens that can be found in the feces and on the hides of meat animals. When hides are removed during the harvest process, the carcass and subsequent meat products can become contaminated. Camels, cattle, sheep, and goats are harvested for meat in Riyadh, Saudi Arabia. The prevalence of E. coli O157:H7 and Salmonella are unknown in these animals, and it is assumed that if the animals carry the pathogens in their feces or on their hides, meat products are likely to become contaminated. To this end, a minimum of 206 samples each from hides and feces of camels, cattle, goats, and sheep were collected over the course of 8 months and tested for E. coli O157:H7 and Salmonella. It was found that E. coli O157:H7 was present in feces (10.7, 1.4, 2.4, and 2.4%) and on hides (17.9, 8.2, 2.9, and 9.2%) of cattle, goats, camels, and sheep, respectively. The prevalence of Salmonella was 11.2, 13.5, 23.2, and 18.8% in feces and 80.2, 51.2 67.6, and 60.2% on hides of cattle, goats, camels, and sheep, respectively. The prevalence of E coli O157:H7 was nearly zero in all samples collected in June and July, while Salmonella did not exhibit any seasonal variation. These results constitute the first comprehensive study of E. coli O157:H7 and Salmonella prevalence in Saudi Arabian meat animals at harvest.

Behavior of Escherichia coli O157:H7 and Listeria monocytogenes during fermentation and storage of camel yogurt.

Science.gov (United States)

Al-Nabulsi, Anas A; Olaimat, Amin N; Osaili, Tareq M; Ayyash, Mutamed M; Abushelaibi, Aisha; Jaradat, Ziad W; Shaker, Reyad; Al-Taani, Mahmoud; Holley, Richard A

2016-03-01

In addition to its nutritional and therapeutic properties, camel milk has the ability to suppress the growth of a wide range of foodborne pathogens, but there is a lack of information regarding the behavior of these pathogens in products such as yogurt produced from camel milk. The objective of the current study was to investigate the behavior of Listeria monocytogenes and Escherichia coli O157:H7 during manufacture and storage of camel yogurt. Camel milk inoculated with L. monocytogenes and E. coli O157:H7 was fermented at 43° C for 5h using freeze-dried lactic acid bacteria (LAB) starter cultures (Streptococcus thermophilus and Lactobacillus bulgaricus) and stored at 4 or 10 °C for 14 d. Camel milk inoculated with L. monocytogenes and E. coli O157:H7 without starter culture was also prepared. During fermentation, the numbers of L. monocytogenes and E. coli O157:H7 increased 0.3 and 1.6 log cfu/mL, respectively, in the presence of LAB, and by 0.3 and 2.7 log cfu/mL in the absence of LAB. During storage at 4 or 10 °C, L. monocytogenes increased 0.8 to 1.2 log cfu/mL by 14 d in camel milk without LAB, but in the presence of LAB, the numbers of L. monocytogenes were reduced by 1.2 to 1.7 log cfu/mL by 14 d. Further, E. coli O157:H7 numbers in camel milk were reduced by 3.4 to 3.5 log cfu/mL in the absence of LAB, but E. coli O157:H7 was not detected (6.3 log cfu/mL reduction) by 7d in camel yogurt made with LAB and stored at either temperature. Although camel milk contains high concentrations of natural antimicrobials, L. monocytogenes was able to tolerate these compounds in camel yogurt stored at refrigerator temperatures. Therefore, appropriate care should be taken during production of yogurt from camel milk to minimize the potential for postprocess contamination by this and other foodborne pathogens. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Growth and survival of Escherichia coli O157:H7 and Listeria monocytogenes in egg products held at different temperatures.

Science.gov (United States)

Yang, S E; Chou, C C

2000-07-01

Growth and survival of Escherichia coli O157:H7 and Listeria monocytogenes in steamed eggs and scrambled eggs held at different temperatures (5, 18, 22, 37, 55, and 60 degrees C) were investigated in the present study. Among the holding temperatures tested, both pathogens multiplied best at 37 degrees C followed by 22, 18, and 5 degrees C. In general, E. coli O157:H7 grew better in the egg products than L. monocytogenes did at all the storage temperatures tested except at 5 degrees C. E. coli O157:H7 did not grow in steamed eggs and scrambled eggs held at 5 degrees C. L. monocytogenes showed a slight population increase of approximately 0.6 to 0.9 log CFU/g in these egg products at the end of the 36-h storage period at 5 degrees C. The population of both pathogens detected in the egg products was affected by the initial population, holding temperature, and length of the holding period. It was also noted that L. monocytogenes was more susceptible than E. coli O157:H7 in steamed eggs held at 60 degrees C. After holding at 60 degrees C for 1 h, no detectable viable cells of L. monocytogenes with a population reduction of 5.4 log CFU/g was observed in steamed eggs, whereas a lower population reduction of only approximately 0.5 log CFU/ml was noted for E. coli O157:H7.

Predictors and risk factors for the intestinal shedding of Escherichia coli O157 among working donkeys (Equus asinus) in Nigeria

Science.gov (United States)

Jedial, Jesse T.; Shittu, Aminu; Tambuwal, Faruk M.; Abubakar, Mikail B.; Garba, Muhammed K.; Kwaga, Jacob P.; Fasina, Folorunso O.

2015-01-01

Objectives Escherichia coli are an important group of bacteria in the normal gastrointestinal system but can sometimes cause infections in domestic animals and man. Donkeys are routinely used as multipurpose animal but details of burdens of potentially infectious bacteria associated with it are limited. The prevalence and associations between intestinal shedding of E. coli O157 and animal characteristics and management factors were studied among 240 randomly selected working donkeys in north-western Nigeria. Design Four local government areas, of Sokoto State in north-western Nigeria were recruited in this study. A multistage randomised cluster design was used to select subjects and donkey owners within selected zones. Confirmation of infection was based on bacterial culture, isolation and biochemical test for E. coli O157 from faecal samples. Results Of the total bacteria isolated, 203 of the 329 (61.70 per cent) were E. coli, 76 of which was E. coli serotype O157. A multivariable logistic regression model was used to examine the relation between intestinal shedding of E. coli O157 and selected variables. The analysis yielded five potential predictors of shedding: soft faeces in donkeys, Akaza and Fari ecotypes of donkey were positive predictors while maize straw as feed and sampling during the cold dry period were negative predictors. Conclusions This study concludes that controlling intestinal shedding of E. coli O157 among working donkeys in Nigeria is possible using the identified predictors in planning appropriate interventions to reduced human risk of infection. PMID:26392892

The purification of the rare earth metals. II

International Nuclear Information System (INIS)

Jordan, R.G.; Jones, D.W.; Hems, V.J.

1975-01-01

Solid-state electrotransport processing has been demonstrated as a technique for purifying terbium. The results show that both oxygen and nitrogen migrate rapidly in the same direction as the electron flow. Although hydrogen contamination occurs on contact with air, terbium of better than 99.9 at. % has been prepared from commercially available starting material. The preparation and characterisation of high-quality single-crystal terbium specimens is also described. (Auth.)

Toward an international standard for PCR-based detection of Escherichia coli O157 - Part 1. Assay development and multi-center validation

DEFF Research Database (Denmark)

Abdulmawjood, A.; Bulte, M.; Cook, N.

2003-01-01

As part of a major European research project, a diagnostic PCR assay, including an internal amplification control, was developed and validated in a collaborative trial for the detection of Escherichia coli O157. The assay is based on amplification of sequences of the rJbE O157 gene. The collabora...

Primary and secondary cases in Escherichia coli O157 outbreaks: a statistical analysis.

LENUS (Irish Health Repository)

Snedeker, Kate G

2009-01-01

BACKGROUND: Within outbreaks of Escherichia coli O157 (E. coli O157), at least 10-15% of cases are thought to have been acquired by secondary transmission. However, there has been little systematic quantification or characterisation of secondary outbreak cases worldwide. The aim of this study was to characterise secondary outbreak cases, estimate the overall proportion of outbreak cases that were the result of secondary transmission and to analyse the relationships between primary and secondary outbreak cases by mode of transmission, country and median age. METHODS: Published data was obtained from 90 confirmed Escherichia coli O157 outbreaks in Great Britain, Ireland, Scandinavia, Canada, the United States and Japan, and the outbreaks were described in terms of modes of primary and secondary transmission, country, case numbers and median case age. Outbreaks were tested for statistically significant differences in the number of ill, confirmed, primary and secondary cases (analysis of variance and Kruskal-Wallis) and in the rate of secondary cases between these variables (Generalised Linear Models). RESULTS: The outbreaks had a median of 13.5 confirmed cases, and mean proportion of 0.195 secondary cases. There were statistically significant differences in the numbers of ill, confirmed, primary and secondary cases between modes of primary transmission (p < 0.021), and in primary and secondary cases between median age categories (p < 0.039) and modes of secondary transmission (p < 0.001).Secondary case rates differed statistically significantly between modes of secondary and primary transmission and median age categories (all p < 0.001), but not between countries (p = 0.23). Statistically significantly higher rates of secondary transmission were found in outbreaks with a median age <6 years and those with secondary transmission via person to person spread in nurseries. No statistically significant interactions were found between country, mode of transmission and age

Influence of Detection Methods in Characterizing Escherichia coli O157:H7 in Raw Goat Meat Using Conventional and Molecular Methods.

Science.gov (United States)

Tabashsum, Zajeba; Nazneen, Mafruha; Ahsan, C R; Bari, M L; Yasmin, M

2016-01-01

　Presence of Escherichia coli O157:H7 on fresh goat meat samples (n= 40) of Dhaka city was analyzed using conventional and molecular methods. A total of 86 presumptive E. coli O157:H7 colonies were isolated from 60% of the samples using selective agar plating method. After conventional biochemical assay followed by API 20E assay, only 11 isolates were found to be E. coli O157:H7. Further serological test identified only four isolates that has strong agglutination reaction against anti-H7 sensitized latex. The biochemically and serologically confirmed isolates were then screened for major virulence factors include eaeA, rfbE, fliC, stx1 and stx2 genes by PCR. PCR analysis of positive isolates showed, 10 isolates were eaeA and rfbE genes positive but fliC gene was only in six, indicating that these isolates were H7 positive with flagellum antigens which might not expressed or detected in serotyping tests. Multiplex PCR against eaeA, stx1 and stx2 genes of the isolates showed similar results as when done individually. These results revealed that only 7% of the primary presumptive E. coli O157:H7 was found to be stx producing E. coli O157:H7 and thus greatly influenced the detection of the pathogen in meat samples.

Survival of bioluminescent Listeria monocytogenes and Escherichia coli O157:H7 in soft cheeses.

Science.gov (United States)

Ramsaran, H; Chen, J; Brunke, B; Hill, A; Griffiths, M W

1998-07-01

Pasteurized and raw milks that had been inoculated at 10(4) cfu/ml with bioluminescent strains of Listeria monocytogenes and Escherichia coli O157:H7 were used in the manufacture of Camembert and Feta cheeses with or without nisin-producing starter culture. Survival of both organisms was determined during the manufacture and storage of Camembert and Feta cheeses at 2 +/- 1 degree C for 65 and 75 d, respectively. Bacterial bioluminescence was used as an indicator to enumerate the colonies plated on selective Listeria agar and on MacConkey agar. Escherichia coli O157:H7 survived the manufacturing process of both cheeses and was present at the end of the storage period in greater numbers than in the initial inoculum. At the end of 75 d of storage, E. coli O157:H7 was found in the brine of Feta cheese. The counts of L. monocytogenes increased as the pH of the Camembert cheese increased, and there were significant differences between the counts from samples taken from the inside and the counts from samples obtained near the surface of the cheese. The Feta cheese that contained nisin was the only cheese in which L. monocytogenes was at the level of the initial inoculum after 75 d of storage.

Prevalence of hydrocephalus in 157 patients with vestibular schwannoma

Energy Technology Data Exchange (ETDEWEB)

Rogg, Jeffrey M.; Ahn, S.H.; Tung, G.A. [Rhode Island Hospital, Department of Diagnostic Imaging, Providence, Rhode Island (United States); Reinert, S.E. [Rhode Island Hospital, Lifespan Medical Computing, Providence, Rhode Island (United States); Noren, G. [Rhode Island Hospital, Department of Neurosurgery, Providence, Rhode Island (United States)

2005-05-01

The purpose of this study was to determine the prevalence of hydrocephalus in patients with vestibular schwannoma. A second objective was to investigate possible etiologies for hydrocephalus in this population by attempting to correlate the incidence and severity of hydrocephalus with tumor volume and extent of fourth ventricular compression. The MRI examinations of 157 adult patients with vestibular schwannoma were retrospectively reviewed. Tumor size was quantified, and the presence of accompanying hydrocephalus was assessed, categorized as communicating type or non-communicating type and then rated as mild, moderate or severe (grades 1-3). Next, the degree of fourth ventricular distortion caused by tumor mass effect was evaluated and categorized as mild, moderate or severe (grades 1-3). Spearman's rank correlation coefficient was used to test the relationships between tumor volume and (1) the extent of fourth ventricular effacement and (2) severity of hydrocephalus. Hydrocephalus was present in 28/157 (18%) cases and was categorized as mild in 11/28 (39%), moderate in 15/28 (54%) and severe in 2/28 (7%). Communicating-type hydrocephalus was present in 17/28 (61%) and non-communicating type in 11/28 (39%). There was a positive correlation between the grade of non-communicating hydrocephalus and tumor volume (r=0.38; P<0.001) and between the severity of fourth ventricular compression and extent of hydrocephalus in this group(r=0.43; P<0.001). (orig.)

Dual Functional Core-Shell Fluorescent Ag2S@Carbon Nanostructure for Selective Assay of E. coli O157:H7 and Bactericidal Treatment.

Science.gov (United States)

Wang, Ning; Wei, Xing; Zheng, An-Qi; Yang, Ting; Chen, Ming-Li; Wang, Jian-Hua

2017-03-24

A dual functional fluorescent core-shell Ag 2 S@Carbon nanostructure is prepared by a hydrothermally assisted multi-amino synthesis approach with folic acid (FA), polyethylenimine (PEI), and mannoses (Mans) as carbon and nitrogen sources (FA-PEI-Mans-Ag 2 S nanocomposite shortly as Ag 2 S@C). The nanostructure exhibits strong fluorescent emission at λ ex /λ em = 340/450 nm with a quantum yield of 12.57 ± 0.52%. Ag 2 S@C is bound to E. coli O157:H7 via strong interaction with the Mans moiety in Ag 2 S@C with FimH proteins on the fimbriae tip in E. coli O157:H7. Fluorescence emission from Ag 2 S@C/E. coli conjugate is closely related to the content of E. coli O157:H7. Thus, a novel procedure for fluorescence assay of E. coli O157:H7 is developed, offering a detection limit of 330 cfu mL -1 . Meanwhile, the Ag 2 S@C nanostructure exhibits excellent antibacterial performance against E. coli O157:H7. A 99.9% sterilization rate can be readily achieved for E. coli O157:H7 at a concentration of 10 6 -10 7 cfu mL -1 with 3.3 or 10 μg mL -1 of Ag 2 S@C with an interaction time of 5 or 0.5 min, respectively.

Screening for virulence genes in Escherichia coli O157:H7 obtained ...

African Journals Online (AJOL)

Eighty (80) sources of drinking water comprising boreholes (24), streams (3), wells (29), pipe-borne (5) and 19 sachet water samples were collected between March 2014 and February 2015. Escherichia coli (E.coli) O157:H7 was isolated by enrichment in Tryptone soy broth at elevated temperature and streaking on Eosin ...

Dynamic of Mutational Events in Variable Number Tandem Repeats of Escherichia coli O157:H7

Directory of Open Access Journals (Sweden)

A. V. Bustamante

2013-01-01

Full Text Available VNTRs regions have been successfully used for bacterial subtyping; however, the hypervariability in VNTR loci is problematic when trying to predict the relationships among isolates. Since few studies have examined the mutation rate of these markers, our aim was to estimate mutation rates of VNTRs specific for verotoxigenic E. coli O157:H7. The knowledge of VNTR mutational rates and the factors affecting them would make MLVA more effective for epidemiological or microbial forensic investigations. For this purpose, we analyzed nine loci performing parallel, serial passage experiments (PSPEs on 9 O157:H7 strains. The combined 9 PSPE population rates for the 8 mutating loci ranged from 4.4 × 10−05 to 1.8 × 10−03 mutations/generation, and the combined 8-loci mutation rate was of 2.5 × 10−03 mutations/generation. Mutations involved complete repeat units, with only one point mutation detected. A similar proportion between single and multiple repeat changes was detected. Of the 56 repeat mutations, 59% were insertions and 41% were deletions, and 72% of the mutation events corresponded to O157-10 locus. For alleles with up to 13 UR, a constant and low mutation rate was observed; meanwhile longer alleles were associated with higher and variable mutation rates. Our results are useful to interpret data from microevolution and population epidemiology studies and particularly point out that the inclusion or not of O157-10 locus or, alternatively, a differential weighting data according to the mutation rates of loci must be evaluated in relation with the objectives of the proposed study.

Complete genome sequence of Bacillus velezensis 157 isolated from Eucommia ulmoides with pathogenic bacteria inhibiting and lignocellulolytic enzymes production by SSF.

Science.gov (United States)

Chen, Long; Gu, Wei; Xu, Hai-Yan; Yang, Gui-Lian; Shan, Xiao-Feng; Chen, Guang; Wang, Chun-Feng; Qian, Ai-Dong

2018-02-01

Bacillus velezensis 157 was isolated from the bark of Eucommia ulmoides , and exhibited antagonistic activity against a broad spectrum of pathogenic bacteria and fungi. Moreover, B. velezensis 157 also showed various lignocellulolytic activities including cellulase, xylanase, α-amylase, and pectinase, which had the ability of using the agro-industrial waste (soybean meal, wheat bran, sugarcane bagasse, wheat straw, rice husk, maize flour and maize straw) under solid-state fermentation and obtained several industrially valuable enzymes. Soybean meal appeared to be the most efficient substrate for the single fermentation of B. velezensis 157. Highest yield of pectinase (19.15 ± 2.66 U g -1 ), cellulase (46.69 ± 1.19 U g -1 ) and amylase (2097.18 ± 15.28 U g -1 ) was achieved on untreated soybean meal. Highest yield of xylanase (22.35 ± 2.24 U g -1 ) was obtained on untreated wheat bran. Here, we report the complete genome sequence of the B. velezensis 157, composed of a circular 4,013,317 bp chromosome with 3789 coding genes and a G + C content of 46.41%, one circular 8439 bp plasmid and a G + C content of 40.32%. The genome contained a total of 8 candidate gene clusters (bacillaene, difficidin, macrolactin, butirosin, bacillibactin, bacilysin, fengycin and surfactin), and dedicates over 15.8% of the whole genome to synthesize secondary metabolite biosynthesis. In addition, the genes encoding enzymes involved in degradation of cellulose, xylan, lignin, starch, mannan, galactoside and arabinan were found in the B. velezensis 157 genome. Thus, the study of B. velezensis 157 broadened that B. velezensis can not only be used as biocontrol agents, but also has potentially a wide range of applications in lignocellulosic biomass conversion.

Effectiveness of lytic bacteriophages in reducing E. coli O157:H7 populations introduced through cross-contamination on fresh cut lettuce

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Previous research has shown that lytic bacteriophages (phages) can kill E. coli O157:H7 on produce surfaces. The role of lytic bacteriophages in preventing cross contamination of produce has not been evaluated. A cocktail of three lytic phages specific for E. coli O157:H7 (EcoShield) at 10^8 PFU/m...

Primer aislamiento de Escherichia coli O157:H7 Enterohemorrágica en el Perú

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Blanca Huapaya C

2001-01-01

Full Text Available En Febrero del año 2001 como parte del "Estudio transversal de los agentes etiológicos de diarrea aguda" en la Macrorregión Sur del país, el Laboratorio Referencial de Tacna aisló una cepa procedente de una muestra de heces de un lactante de 11 meses de edad con un cuadro de diarrea disentérica, identificándola como Escherichia coli O157. Esta cepa fue confirmada y caracterizada en el Instituto Nacional de Salud como E. coli O157:H7 toxina shiga tipo II, siendo el primer aislamiento reportado de Escherichia coli enterohemorrágica en el Perú.

Determination of gamma radiation dose to the destruction of Escherichia coli O157: H7 in hamburger

International Nuclear Information System (INIS)

Orejuela Chirinos, Rodolfo Raul

1999-01-01

Escherichia coli O157:H7 has been incriminated in several foodborne outbreaks due to the consumption of different kinds of foods. Among these, hamburgers are the most common. Irradiation process is an effective method for food preservation because it causes no significant change in organoleptic and nutritional food characteristics and destroys pathogens and spoilage microorganisms. Hamburgers and nutrient broth inoculated with Escherichia coli O157:H7 were submitted to gamma irradiation ( 60 Co) treatment, with doses ranging from 0,0 to 0,7 kGy in order to calculate the D 10 for this bacteria in these substrate. The D 10 for the pathogen nutrient broth ranged from 0.08 kGy to 0.10 kGy and in hamburger from 0.11 kGy to 0.21 kGy. Considering the highest D 10 value in hamburger, a dose of 0,8 kGy would not change the sensorial characteristics of the product, and would reduce the population of E. coli O157:H7 in 4 cycles logarithmic. (author)

Preparation of immunomagnetic iron-dextran nanoparticles and application in rapid isolation of E.coli O157:H7 from foods

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Duan, Hui-Li; Shen, Zhi-Qiang; Wang, Xin-Wei; Chao, Fu-Huan; Li, Jun-Wen

2005-01-01

AIM: To prepare a kind of magnetic iron-dextran nanoparticles that was coated with anti-E.coli O157:H7 IgG, analyze its application conditions, and try to use it to isolate E.coli O157:H7 from foods. METHODS: Magnetic iron-dextran nanoparticles were prepared by the reaction of a mixture of ferric and ferrous ions with dextran polymers under alkaline conditions. The particles were coated with antiserum against E.coli O157:H7 by the periodate oxidation-borohydride reduction procedure. The oxidation time, amount of antibody coating the particles, amount of nanoparticles, incubation time and isolation time were varied to determine their effects on recovery of the organisms. Finally, the optimum conditions for isolating E.coli O157:H7 from food samples were established. RESULTS: E.coli O157:H7 can be isolated from samples within 15 min with the sensitivity of 101 CFU/mL or even less. In the presence of 108 CFU/mL of other organisms, the sensitivity is 101-102 CFU/mL. Nonspecific binding of other bacteria to the particles was not observed. Two and a half hours of enrichment is enough for the particles to detect the target from the food samples inoculated with 1 CFU/g. CONCLUSION: Isolation of target bacteria by immuno-magnetic nanoparticles is an efficient method with high sensitivity and specificity. The technique is so simple that it can be operated in lab and field even by untrained personnel. PMID:15968716

Efficacy of chlorine, acidic electrolyzed water and aqueous chlorine dioxide solutions to decontaminate Escherichia coli O157:H7 from lettuce leaves.

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Keskinen, Lindsey A; Burke, Angela; Annous, Bassam A

2009-06-30

This study compared the efficacy of chlorine (20-200 ppm), acidic electrolyzed water (50 ppm chlorine, pH 2.6), acidified sodium chlorite (20-200 ppm chlorite ion concentration, Sanova), and aqueous chlorine dioxide (20-200 ppm chlorite ion concentration, TriNova) washes in reducing populations of Escherichia coli O157:H7 on artificially inoculated lettuce. Fresh-cut leaves of Romaine or Iceberg lettuce were inoculated by immersion in water containing E. coli O157:H7 (8 log CFU/ml) for 5 min and dried in a salad spinner. Leaves (25 g) were then washed for 2 min, immediately or following 24 h of storage at 4 degrees C. The washing treatments containing chlorite ion concentrations of 100 and 200 ppm were the most effective against E. coli O157:H7 populations on Iceberg lettuce, with log reductions as high as 1.25 log CFU/g and 1.05 log CFU/g for TriNova and Sanova wash treatments, respectively. All other wash treatments resulted in population reductions of less than 1 log CFU/g. Chlorine (200 ppm), TriNova, Sanova, and acidic electrolyzed water were all equally effective against E. coli O157:H7 on Romaine, with log reductions of approximately 1 log CFU/g. The 20 ppm chlorine wash was as effective as the deionized water wash in reducing populations of E. coli O157:H7 on Romaine and Iceberg lettuce. Scanning electron microscopy indicated that E. coli O157:H7 that was incorporated into biofilms or located in damage lettuce tissue remained on the lettuce leaf, while individual cells on undamaged leaf surfaces were more likely to be washed away.

Role of curli and plant cultivation conditions on Escherichia coli O157:H7 internalization into spinach grown on hydroponics and in soil.

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Macarisin, Dumitru; Patel, Jitendra; Sharma, Vijay K

2014-03-03

Contamination of fresh produce could represent a public health concern because no terminal kill step is applied during harvest or at the processing facility to kill pathogens. In addition, once contaminated, pathogens may internalize into produce and be protected from disinfectants during the postharvest processing step. The objective of the current study was to determine the potential internalization of Escherichia coli O157:H7 into spinach roots and subsequent transfer to the edible parts. Because curli are involved in biofilm formation, we investigated whether their presence influence the internalization of E. coli O157:H7 into spinach. Further, the effect of the spinach cultivar on E. coli O157:H7 internalization was evaluated. Spinach plants were grown in contaminated soil as well as hydroponically to prevent mechanical wounding of the roots and inadvertent transfer of pathogens from the contamination source to the non-exposed plant surfaces. Results showed that E. coli O157:H7 could internalize into hydroponically grown intact spinach plants through the root system and move to the stem and leaf level. The incidence of internalization was significantly higher in hydroponically grown plants when roots were exposed to 7 log CFU/mL compared to those exposed to 5 log CFU/mL. The effect of cultivar on E. coli O157:H7 internalization was not significant (P>0.05) for the analyzed spinach varieties, internalization incidences showing almost equal distribution between Space and Waitiki, 49.06% and 50.94% respectively. Wounding of the root system in hydroponically grown spinach increased the incidence of E. coli O157:H7 internalization and translocation to the edible portions of the plant. Experimental contamination of the plants grown in soil resulted in a greater number of internalization events then in those grown hydroponically, suggesting that E. coli O157:H7 internalization is dependent on root damage, which is more likely to occur when plants are grown in soil

Antibacterial activity of selected plant essential oils against Escherichia coli O157:H7.

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Burt, S A; Reinders, R D

2003-01-01

To quantify the antibacterial properties of five essential oils (EO) on a non-toxigenic strain of Escherichia coli O157:H7 in the presence and absence of a stabilizer and an emulsifier and at three different temperatures. Five EOs known to exhibit antibacterial properties were screened by disc diffusion assay and the most active were selected for further study in microdilution colorimetric assays. Oregano (Origanum vulgare) and thyme (Thymus vulgaris; light and red varieties) EO had the strongest bacteriostatic and bactericidal properties, followed by bay (Pimenta racemosa) and clove bud (Eugenia caryophyllata synonym: Syzygium aromaticum) EO. Oregano oil was colicidal at 625 microl l(-1) at 10, 20 and 37 degrees C. The addition of 0.05% (w/v) agar as stabilizer reinforced the antibacterial properties, particularly at 10 degrees C, whereas 0.25% (w/v) lecithin reduced antibacterial activity. Scanning electron micrographs showed extensive morphological changes to treated cells. Oregano and thyme EO possess significant in vitro colicidal and colistatic properties, which are exhibited in a broad temperature range and substantially improved by the addition of agar as stabilizer. Bay and clove bud EO are less active. Lecithin diminished antibacterial properties. The bactericidal concentration of oregano EO irreversibly damaged E. coli O157:H7 cells within 1 min. Oregano and light thyme EO, particularly when enhanced by agar stabilizer, may be effective in reducing the number or preventing the growth of E. coli O157:H7 in foods.

A portable smart-phone device for rapid and sensitive detection of E. coli O157:H7 in Yoghurt and Egg.

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Zeinhom, Mohamed Maarouf Ali; Wang, Yijia; Song, Yang; Zhu, Mei-Jun; Lin, Yuehe; Du, Dan

2018-01-15

The detection of E. coli O157:H7 in foods has held the attention of many researchers because of the seriousness attributed to this pathogen. In this study, we present a simple, sensitive, rapid and portable smartphone based fluorescence device for E. coli O157:H7 detection. This field-portable fluorescent imager on the smartphone involves a compact laser-diode-based photosource, a long-pass (LP) thin-film interference filter and a high-quality insert lenses. The design of the device provided a low noise to background imaging system. Based on a sandwich ELISA and the specific recognition of antibody to E. coli O157:H7, the sensitive detection of E. coli O157:H7 were realized both in standard samples and real matrix in yoghurt and egg on our device. The detection limit are 1 CFU/mL and 10 CFU/mL correspondingly. Recovery percentages of spiked yogurt and egg samples with 10 3 , 10 4 and 10 5 CFU/mL E. coli O157:H7 were 106.98, 96.52 and 102.65 (in yogurt) and 107.37, 105.64 and 93.84 (in egg) samples using our device, respectively. Most importantly, the entire process could be quickly completed within two hours. This smartphone based device provides a simple, rapid, sensitive detection platform for fluorescent imaging which applied in pathogen detection for food safety monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

Microarray-Based Screening of Differentially Expressed Genes of E. coli O157:H7 Sakai during Preharvest Survival on Butterhead Lettuce

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Inge Van der Linden

2016-01-01

Full Text Available Numerous outbreaks of Escherichia coli O157:H7 have been linked to the consumption of leafy vegetables. However, up to the present, little has been known about E. coli O157:H7’s adaptive responses to survival on actively growing (and thus responsive plants. In this study, whole genome transcriptional profiles were generated from E. coli O157:H7 cells (isolate Sakai, stx- one hour and two days after inoculation on the leaves of growing butterhead lettuce, and compared with an inoculum control. A total of 273 genes of E. coli O157:H7 Sakai (5.04% of the whole genome were significantly induced or repressed by at least two-fold (p < 0.01 in at least one of the analyzed time points in comparison with the control. Several E. coli O157:H7 genes associated with oxidative stress and antimicrobial resistance were upregulated, including the iron-sulfur cluster and the multiple antibiotic resistance (mar operon, whereas the Shiga toxin virulence genes were downregulated. Nearly 40% of the genes with significantly different expression were poorly characterized genes or genes with unknown functions. These genes are of special interest for future research as they may play an important role in the pathogens’ adaptation to a lifestyle on plants. In conclusion, these findings suggest that the pathogen actively interacts with the plant environment by adapting its metabolism and responding to oxidative stress.

Fate of naturally occurring Escherichia coli O157:H7 and other zoonotic pathogens during minimally managed bovine feedlot manure composting processes

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Reducing Escherichia coli O157:H7 in livestock manures before application to cropland is critical for reducing the risk of foodborne illness associated with produce. Our objective was to determine the fate of naturally occurring E. coli O157:H7 and other pathogens during minimally managed on-farm bo...

Using fluorescence measurement of zinc ions liberated from ZnS nanoparticle labels in bioassay for Escherichia coli O157:H7

International Nuclear Information System (INIS)

Cowles, Chad L.; Zhu Xiaoshan; Pai, Chi-Yun

2011-01-01

In this study, an alternative approach using ZnS nanoparticle biolabels as fluorescence signal transducers is reported for the immunoassay of E. coli O157:H7 in tap water samples. Instead of measuring the fluorescence of ZnS nanoparticles in the assay, the fluorescence signal is generated through the binding of zinc ions released from nanoparticle labels with zinc-ion sensitive fluorescence indicator Fluozin-3. In the assay, ZnS nanoparticles around 50 nm in diameter were synthesized, bioconjugated, and applied for the detection of E. coli O157:H7. The assay shows a detection range over two orders of magnitude and a detection limit around 1000 colony-forming units (cfu) of E. coli O157:H7.

Assessment of the Contamination of Some Foodstuffs by Escherichia coli O157 in Benin, West Africa

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Honoré Sourou Bankole

2014-01-01

Full Text Available Escherichia coli O157 is a pathogenic bacterium causing haemorrhagic colitis. It represents a serious public health problem in Northern America and Europe, which can plague Africa. Most cases of mentioned poisoning were related to contaminated meat products and vegetables. The present work aimed to estimate the prevalence of E. coli O157 in meat and vegetables in Benin. For this purpose, 6 lots of faeces samples from pigs and 8 from cattle were collected at the farms on the outskirts of Cotonou. Similarly, 20 samples of carcasses, 20 samples of intestines and stomach, and 20 surfaces samples of slaughtering equipment were taken. Vegetables and environment materials in gardens have also been sampled for 84 samples. Bacteriological analyses revealed a percentage of contamination of 50% for pig faeces and 25% for cattle ones. All the meats from stalling parks have been contaminated by this bacterium. For vegetables, 14.6% of samples were contaminated by E. coli O157. The presence of this pathovar in animal breeding and slaughtering environment and in the gardens shows that Benin is not aware of the risks of foodborne illness associated with the consumption of contaminated products. Therefore, it urges including that germ in a systematic search during safety control of food products in Benin.

[Construction of enterohemorrhagic Escherichia coli O157:H7 strains with espF gene deletion and complementation].

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Hua, Ying; Sun, Qi; Wang, Xiangyu; DU, Yanli; Shao, Na; Zhang, Qiwei; Zhao, Wei; Wan, Chengsong

2015-11-01

To construct enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains with delection espF gene and its nucleotide fragment and with espF gene complementation. A pair of homologous arm primers was designed to amplify the gene fragment of kanamycin resistance, which was transformed into EHEC O157:H7 EDL933w strain via the PKD46 plasmid by electroporation. The replacement of the espF gene by kanamycin resistance gene through the PKD46-mediated red recombination system was confirmed by PCR and sequencing. The entire coding region of espF along with its nucleotide fragment was amplified by PCR and cloned into pBAD33 plasmid, which was transformed into a mutant strain to construct the strain with espF complementation. RT-PCR was used to verify the transcription of espF and its nucleotide fragment in the complemented mutant strain. We established EHEC O157:H7 EDL933w strains with espF gene deletion and with espF gene complementation. Both espF and its nucleotide fragment were transcribed in the complemented mutant strain. The two strains provide a basis for further study of the regulatory mechanism of espF.

Lethality Prediction for Escherichia Coli O157:H7 and Uropathogenic E. coli in Ground Chicken Treated with High Pressure Processing and Trans-Cinnamaldehyde.

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Sheen, Shiowshuh; Huang, Chi-Yun; Ramos, Rommel; Chien, Shih-Yung; Scullen, O Joseph; Sommers, Christopher

2018-03-01

Pathogenic Escherichia coli, intestinal (O157:H7) as well as extraintestinal types (for example, Uropathogenic E. coli [UPEC]) are commonly found in many foods including raw chicken meat. The resistance of E. coli O157:H7 to UPEC in chicken meat under the stresses of high hydrostatic Pressure (HHP, also known as HPP-high pressure processing) and trans-cinnamaldehyde (an essential oil) was investigated and compared. UPEC was found slightly less resistant than O157:H7 in our test parameter ranges. With the addition of trans-cinnamaldehyde as an antimicrobial to meat, HPP lethality enhanced both O157:H7 and UPEC inactivation. To facilitate the predictive model development, a central composite design (CCD) was used to assess the 3-parameter effects, that is, pressure (300 to 400 MPa), trans-cinnamaldehyde dose (0.2 to 0.5%, w/w), and pressure-holding time (15 to 25 min), on the inactivation of E. coli O157:H7 and UPEC in ground chicken. Linear models were developed to estimate the lethality of E. coli O157:H7 (R 2 = 0.86) and UPEC (R 2 = 0.85), as well as dimensionless nonlinear models. All models were validated with data obtained from separated CCD combinations. Because linear models of O157:H7 and UPEC had similar R 2 and the significant lethality difference of CCD points was only 9 in 20; all data were combined to generate models to include both O157:H7 and UPEC. The results provide useful information/tool to predict how pathogenic E. coli may survive HPP in the presence of trans-cinnamaldehyde and to achieve a great than 5 log CFU/g reduction in chicken meat. The models may be used for process optimization, product development and to assist the microbial risk assessment. The study provided an effective means to reduce the high hydrostatic pressure level with incorporation of antimicrobial compound to achieve a 5-log reduction of pathogenic E. coli without damaging the raw meat quality. The developed models may be used to predict the high pressure processing

Portable and quantitative point-of-care monitoring of Escherichia coli O157:H7 using a personal glucose meter based on immunochromatographic assay.

Science.gov (United States)

Huang, Haoran; Zhao, Guangying; Dou, Wenchao

2018-06-01

Here we innovate a portable and quantitative immunochromatographic assay (ICA) with a personal glucose meter (PGM) as readout for the detection of Escherichia coli O157:H7 (E. coli O157:H7). The carboxyl group coated Fe 3 O 4 nanoparticles (MNPs) were synthesized by a one pot method and used as carriers of invertase and monoclonal antibody against E. coli O157:H7. Initially, the invertase and antibody double functionalized MNPs (Invertase-MNPs-IgG) conjugates were prepared and used as label probe in this assay system. Before laminating onto the baking card, the absorbent pad was soaked in sucrose solution and desiccated. MNPs produced brown band at the detection zone of the ICA when acting as direct labels. As they were also coupled with invertase, the invertase catalyzed the hydrolysis of sucrose on the absorbent pad into glucose, which was detected by the PGM. To increase the sensitivity, antibody functionalized MNPs were used to enrich E. coli O157:H7 from sample solution. The innovative aspect of this approach lies in the visualization and quantification of E. coli O157:H7 through Invertase-MNPs-IgG and the detection of glucose concentration using PGM. Although the feasibility is demonstrated using E. coli O157:H7 as a model analyte, this approach can be easily developed to be a universal analysis system and applied to detection of a wide variety of foodborne pathogens and protein biomarkers. This study proposed a qualitative and quantitative analysis device for the clinic diagnostics and food safety analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

Isolation and characterization of non-O157 Shiga toxin-producing Escherichia coli from beef carcasses, cuts and trimmings of abattoirs in Argentina

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Brusa, Victoria; Restovich, Viviana; Galli, Lucía; Teitelbaum, David; Signorini, Marcelo; Brasesco, Hebe; Londero, Alejandra; García, Diego; Padola, Nora Lía; Superno, Valeria; Sanz, Marcelo; Petroli, Sandra; Costa, Magdalena; Bruzzone, Mariana; Sucari, Adriana; Ferreghini, Marcela; Linares, Luciano; Suberbie, Germán; Rodríguez, Ricardo

2017-01-01

Several foods contaminated with Shiga toxin-producing Escherichia coli (STEC) are associated with human diseases. Some countries have established microbiological criteria for non-O157 STEC, thus, the absence of serogroups O26, O45, O103, O104, O111, O121, and O145 in sprouts from the European Union or ground beef and beef trimmings from the United States is mandatory. While in Argentina screening for O26, O103, O111, O145 and O121 in ground beef, ready-to-eat food, sausages and vegetables is mandatory, other countries have zero-tolerance for all STEC in chilled beef. The aim of this study was to provide data on the prevalence of non-O157 STEC isolated from beef processed in eight Argentinean cattle slaughterhouses producing beef for export and local markets, and to know the non-O157 STEC profiles through strain characterization and genotypic analysis. Samples (n = 15,965) from 3,205 beef carcasses, 9,570 cuts and 3,190 trimmings collected between March and September 2014 were processed in pools of five samples each. Pools of samples (n = 3,193) from 641 carcasses, 1,914 cuts and 638 trimming were analyzed for non-O157 STEC isolation according to ISO/CEN 13136:2012. Of these, 37 pools of carcasses (5.8%), 111 pools of cuts (5.8%) and 45 pools of trimmings (7.0%) were positive for non-O157 STEC. STEC strains (n = 200) were isolated from 193 pools of samples. The most prevalent serotypes were O174:H21, O185:H7, O8:H19, O178:H19 and O130:H11, and the most prevalent genotypes were stx2c(vh-b) and stx2a/saa/ehxA. O103:H21 strain was eae-positive and one O178:H19 strain was aggR/aaiC-positive. The prevalence of non-O157 STEC in beef carcasses reported here was low. None of the non-O157 STEC strains isolated corresponded to the non-O157 STEC serotypes and virulence profiles isolated from human cases in Argentina in the same study period. The application of microbiological criteria for each foodstuff should be determined by risk analysis in order to have a stringent

Isolation and characterization of non-O157 Shiga toxin-producing Escherichia coli from beef carcasses, cuts and trimmings of abattoirs in Argentina.

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Victoria Brusa

Full Text Available Several foods contaminated with Shiga toxin-producing Escherichia coli (STEC are associated with human diseases. Some countries have established microbiological criteria for non-O157 STEC, thus, the absence of serogroups O26, O45, O103, O104, O111, O121, and O145 in sprouts from the European Union or ground beef and beef trimmings from the United States is mandatory. While in Argentina screening for O26, O103, O111, O145 and O121 in ground beef, ready-to-eat food, sausages and vegetables is mandatory, other countries have zero-tolerance for all STEC in chilled beef. The aim of this study was to provide data on the prevalence of non-O157 STEC isolated from beef processed in eight Argentinean cattle slaughterhouses producing beef for export and local markets, and to know the non-O157 STEC profiles through strain characterization and genotypic analysis. Samples (n = 15,965 from 3,205 beef carcasses, 9,570 cuts and 3,190 trimmings collected between March and September 2014 were processed in pools of five samples each. Pools of samples (n = 3,193 from 641 carcasses, 1,914 cuts and 638 trimming were analyzed for non-O157 STEC isolation according to ISO/CEN 13136:2012. Of these, 37 pools of carcasses (5.8%, 111 pools of cuts (5.8% and 45 pools of trimmings (7.0% were positive for non-O157 STEC. STEC strains (n = 200 were isolated from 193 pools of samples. The most prevalent serotypes were O174:H21, O185:H7, O8:H19, O178:H19 and O130:H11, and the most prevalent genotypes were stx2c(vh-b and stx2a/saa/ehxA. O103:H21 strain was eae-positive and one O178:H19 strain was aggR/aaiC-positive. The prevalence of non-O157 STEC in beef carcasses reported here was low. None of the non-O157 STEC strains isolated corresponded to the non-O157 STEC serotypes and virulence profiles isolated from human cases in Argentina in the same study period. The application of microbiological criteria for each foodstuff should be determined by risk analysis in order to have a

Potential application of high hydrostatic pressure to eliminate Escherichia coli O157:H7 on alfalfa sprouted seeds.

Science.gov (United States)

Neetoo, Hudaa; Ye, Mu; Chen, Haiqiang

2008-12-10

Sprouts eaten raw are increasingly being perceived as hazardous foods as they have been implicated in Escherichia coli O157:H7 outbreaks where the seeds were found to be the likely source of contamination. The objective of our study was to evaluate the potential of using high hydrostatic pressure (HHP) technology for alfalfa seed decontamination. Alfalfa seeds inoculated with a cocktail of five strains of E. coli O157:H7 were subjected to pressures of 500 and 600 MPa for 2 min at 20 degrees C in a dry or wet (immersed in water) state. Immersing seeds in water during pressurization considerably enhanced inactivation of E. coli O157:H7 achieving reductions of 3.5 log and 5.7 log at 500 and 600 MPa, respectively. When dry seeds were pressurized, both pressure levels reduced the counts by 5 log reduction in the population was achieved when 600 MPa was applied for durations of > or =6 min although survivors were still detected by enrichment. When the pressure was stepped up to 650 MPa, the threshold time required to achieve complete elimination was 15 min. Un-inoculated seeds pressure-treated at 650 MPa for 15 min at 20 degrees C successfully sprouted achieving a germination rate identical to untreated seeds after eight days of sprouting. These results therefore demonstrate the promising application of HHP on alfalfa seeds to eliminate the risk of E. coli O157:H7 infections associated with consumption of raw alfalfa sprouts.

Escherichia coli O157:H7 Converts Plant-Derived Choline to Glycine Betaine for Osmoprotection during Pre- and Post-harvest Colonization of Injured Lettuce Leaves

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Russell A. Scott

2017-12-01

Full Text Available Plant injury is inherent to the production and processing of fruit and vegetables. The opportunistic colonization of damaged plant tissue by human enteric pathogens may contribute to the occurrence of outbreaks of foodborne illness linked to produce. Escherichia coli O157:H7 (EcO157 responds to physicochemical stresses in cut lettuce and lettuce lysates by upregulation of several stress response pathways. We investigated the tolerance of EcO157 to osmotic stress imposed by the leakage of osmolytes from injured lettuce leaf tissue. LC-MS analysis of bacterial osmoprotectants in lettuce leaf lysates and wound washes indicated an abundant natural pool of choline, but sparse quantities of glycine betaine and proline. Glycine betaine was a more effective osmoprotectant than choline in EcO157 under osmotic stress conditions in vitro. An EcO157 mutant with a deletion of the betTIBA genes, which are required for biosynthesis of glycine betaine from imported choline, achieved population sizes twofold lower than those of the parental strain (P < 0.05 over the first hour of colonization of cut lettuce in modified atmosphere packaging (MAP. The cell concentrations of the betTIBA mutant also were 12-fold lower than those of the parental strain (P < 0.01 when grown in hypertonic lettuce lysate, indicating that lettuce leaf cellular contents provide choline for osmoprotection of EcO157. To demonstrate the utilization of available choline by EcO157 for osmoadaptation in injured leaf tissue, deuterated (D-9 choline was introduced to wound sites in MAP lettuce; LC-MS analysis revealed the conversion of D9-choline to D-9 glycine betaine in the parental strain, but no significant amounts were observed in the betTIBA mutant. The EcO157 ΔbetTIBA-ΔotsBA double mutant, which is additionally deficient in de novo synthesis of the compatible solute trehalose, was significantly less fit than the parental strain after their co-inoculation onto injured lettuce leaves and

Thermal tolerance of acid-adapted and unadapted Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in cantaloupe juice and watermelon juice.

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Sharma, M; Adler, B B; Harrison, M D; Beuchat, L R

2005-01-01

A study was performed to determine D values of acid-adapted and unadapted cells of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in cantaloupe juice and watermelon juice. Salmonella enterica serotype Poona, S. enterica serotype Saphra, two strains of E. coli O157:H7, and two strains of L. monocytogenes were grown in tryptic soy broth (TSB) and TSB supplemented with 1% glucose for 24 h at 37 degrees C. Decimal reduction times (D values) of cells suspended in unpasteurized cantaloupe juice and watermelon juice were determined. Acid-adapted cells of Salmonella and E. coli O157:H7, but not L. monocytogenes, had increased thermal tolerance compared with cells that were not acid-adapted. There was no correlation between soluble solids content of the two types of juice and thermal resistance. Growth of Salmonella and E. coli O157:H7 in cantaloupe juice, watermelon juice, or other acidic milieu, either in preharvest or postharvest environments, may result in cross protection to heat. The pasteurization conditions necessary to achieve elimination of pathogens from these juices would consequently have to be more severe if cells are habituated to acidic environments. Insights from this study provide guidance to developing pasteurization processes to eliminate Salmonella, E. coli O157:H7, and L. monocytogenes in cantaloupe juice and watermelon juice.

Health Risk of Escherichia coli O157:H7 in Drinking Water and Meat and Meat Products and Vegetables to Diarrhoeic Confirmed and Non-Confirmed HIV/AIDS Patients

Science.gov (United States)

Abong`O, B. O.; Momba, M. N. B.; Rodda, N.

The current study explored the health risk of E. coli O157:H7 to diarrhoeic confirmed and non-confirmed HIV/AIDS patients due to their exposure to presumed ingestion of water, meat products and vegetables ostensibly contaminated with E. coli O157:H7. Strains of E. coli O157:H7 were isolated by enrichment culture and on Cefixime-Telurite Sorbitol MacConkey agar. Average counts of presumptive E. coli O157 were used for dose-response assessment. Probability of infection to confirmed and non-confirmed HIV/AIDS patients was 20 and 27% from meat and meat products, 21% and 15% from vegetables and 100% due to ingestion of 1500 mL person-1 day-1 of water. Drinking water had higher probability of transmitting E. coli O157:H7 infections than meat and meat products and vegetables. Probability of E. coli O157:H7 infections were high for confirmed HIV/AIDS patients than for non-confirmed patients. Water and foods consumed by HIV/AIDS patients should be safe of any microbial contaminants, these waters and foods should as well be investigated for other enteric pathogens to establish their safety.

A sensitive lateral flow biosensor for Escherichia coli O157:H7 detection based on aptamer mediated strand displacement amplification

Energy Technology Data Exchange (ETDEWEB)

Wu, Wei [College of Food Science and Engineering, Ocean University of China, Qingdao 266003 (China); Zhao, Shiming [Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China); Mao, Yiping [Yueyang Institute for Food and Drug Control, Yueyang 430198 (China); Fang, Zhiyuan [Affiliated Tumor Hospital of Guangzhou Medical University, Guangzhou 510095 (China); Lu, Xuewen [Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China); Zeng, Lingwen, E-mail: zeng6@yahoo.com [Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China)

2015-02-25

Highlights: • Limit of detection as low as 10 CFU mL{sup −1}Escherichia coli O157:H7. • No need of antibodies and substituted with aptamers. • Isothermal strand displacement amplification for signal amplification. • Results observed by the naked eye. • Great potential application in the area of food control. - Abstract: Foodborne diseases caused by pathogens are one of the major problems in food safety. Convenient and sensitive point-of-care rapid diagnostic tests for food-borne pathogens have been a long-felt need of clinicians. Commonly used methods for pathogen detection rely on conventional culture-based tests, antibody-based assays and polymerase chain reaction (PCR)-based techniques. These methods are costly, laborious and time-consuming. Herein, we present a simple and sensitive aptamer based biosensor for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7). In this assay, two different aptamers specific for the outmembrane of E. coli O157:H7 were used. One of the aptamers was used for magnetic bead enrichment, and the other was used as a signal reporter for this pathogen, which was amplified by isothermal strand displacement amplification (SDA) and further detected by a lateral flow biosensor. Only the captured aptamers on cell membrane were amplified, limitations of conventional DNA amplification based method such as false-positive can be largely reduced. The generated signals (red bands on the test zone of a lateral flow strip) can be unambiguously read out by the naked eye. As low as 10 colony forming units (CFU) of E. coli O157:H7 were detected in this study. Without DNA extraction, the reduced handling and simpler equipment requirement render this assay a simple and rapid alternative to conventional methods.

A sensitive lateral flow biosensor for Escherichia coli O157:H7 detection based on aptamer mediated strand displacement amplification

International Nuclear Information System (INIS)

Wu, Wei; Zhao, Shiming; Mao, Yiping; Fang, Zhiyuan; Lu, Xuewen; Zeng, Lingwen

2015-01-01

Highlights: • Limit of detection as low as 10 CFU mL −1 Escherichia coli O157:H7. • No need of antibodies and substituted with aptamers. • Isothermal strand displacement amplification for signal amplification. • Results observed by the naked eye. • Great potential application in the area of food control. - Abstract: Foodborne diseases caused by pathogens are one of the major problems in food safety. Convenient and sensitive point-of-care rapid diagnostic tests for food-borne pathogens have been a long-felt need of clinicians. Commonly used methods for pathogen detection rely on conventional culture-based tests, antibody-based assays and polymerase chain reaction (PCR)-based techniques. These methods are costly, laborious and time-consuming. Herein, we present a simple and sensitive aptamer based biosensor for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7). In this assay, two different aptamers specific for the outmembrane of E. coli O157:H7 were used. One of the aptamers was used for magnetic bead enrichment, and the other was used as a signal reporter for this pathogen, which was amplified by isothermal strand displacement amplification (SDA) and further detected by a lateral flow biosensor. Only the captured aptamers on cell membrane were amplified, limitations of conventional DNA amplification based method such as false-positive can be largely reduced. The generated signals (red bands on the test zone of a lateral flow strip) can be unambiguously read out by the naked eye. As low as 10 colony forming units (CFU) of E. coli O157:H7 were detected in this study. Without DNA extraction, the reduced handling and simpler equipment requirement render this assay a simple and rapid alternative to conventional methods

Transfer coefficient models for escherichia coli O157:H7 on contacts between beef tissue and high-density polyethylene surfaces.

Science.gov (United States)

Flores, Rolando A; Tamplin, Mark L; Marmer, Benne S; Phillips, John G; Cooke, Peter H

2006-06-01

Risk studies have identified cross-contamination during beef fabrication as a knowledge gap, particularly as to how and at what levels Escherichia coli O157:H7 transfers among meat and cutting board (or equipment) surfaces. The objectives of this study were to determine and model transfer coefficients (TCs) between E. coli O157:H7 on beef tissue and high-density polyethylene (HDPE) cutting board surfaces. Four different transfer scenarios were evaluated: (i) HDPE board to agar, (ii) beef tissue to agar, (iii) HDPE board to beef tissue to agar, and (iv) beef tissue to HDPE board to agar. Also, the following factors were studied for each transfer scenario: two HDPE surface roughness levels (rough and smooth), two beef tissues (fat and fascia), and two conditions of the initial beef tissue inoculation with E. coli O157:H7 (wet and dry surfaces), for a total of 24 treatments. The TCs were calculated as a function of the plated inoculum and of the cells recovered from the first contact. When the treatments were compared, all of the variables evaluated interacted significantly in determining the TC. An overall TC-per-treatment model did not adequately represent the reduction of the cells on the original surface after each contact and the interaction of the factors studied. However, an exponential model was developed that explained the experimental data for all treatments and represented the recontamination of the surfaces with E. coli O157:H7. The parameters for the exponential model for cross-contamination with E. coli O157:H7 between beef tissue and HDPE surfaces were determined, allowing for the use of the resulting model in quantitative microbial risk assessment.

Impact of persistent and nonpersistent generic Escherichia coli and Salmonella sp. recovered from a beef packing plant on biofilm formation by E. coli O157.

Science.gov (United States)

Visvalingam, J; Ells, T C; Yang, X

2017-12-01

To examine the influence of meat plant Escherichia coli and Salmonella sp. isolates on E. coli O157 biofilm formation. Biofilm formation was quantified by crystal violet staining (A 570 nm ) and viable cell numbers for up to 6 days at 15°C. All five persistent E. coli genotypes formed strong biofilms when cultured alone or co-cultured with E. coli O157, with A 570 nm values reaching ≥4·8 at day 4, while only two of five nonpersistent genotypes formed such biofilms. For E. coli O157:H7 co-culture biofilms with E. coli genotypes 136 and 533, its numbers were ≥1·5 and ≥1 log CFU per peg lower than those observed for its mono-culture biofilm at days 2 and 4, respectively. The number of E. coli O157:NM in similar co-culture biofilms was 1 log CFU per peg lower than in its mono-culture biofilm at day 4 and 6, respectively. Salmonella sp. lowered the number of E. coli O157:NM by 0·5 log unit, once, at day 6. Generic E. coli may outcompete E. coli O157 strains while establishing biofilms. Findings advance knowledge regarding inter-strain competition for a similar ecological niche and may aid development of biocontrol strategies for E. coli O157 in food processing environments. © 2017 Her Majesty the Queen in Right of Canada. Journal of Applied Microbiology © 2017 The Society for Applied Microbiology Reproduced with the permission of the Minister of the Department of Agriculture and Agri-Food Canada.

Preharvest internalization of Escherichia coli O157:H7 into lettuce leaves, as affected by insect and physical damage.

Science.gov (United States)

Erickson, Marilyn C; Liao, Jean; Payton, Alison S; Riley, David G; Webb, Cathy C; Davey, Lindsey E; Kimbrel, Sophia; Ma, Li; Zhang, Guodong; Flitcroft, Ian; Doyle, Michael P; Beuchat, Larry R

2010-10-01

Environmental pests may serve as reservoirs and vectors of zoonotic pathogens to leafy greens; however, it is unknown whether insect pests feeding on plant tissues could redistribute these pathogens present on the surface of leaves to internal sites. This study sought to differentiate the degree of tissue internalization of Escherichia coli O157:H7 when applied at different populations on the surface of lettuce and spinach leaves, and to ascertain whether lettuce-infesting insects or physical injury could influence the fate of either surface or internalized populations of this enteric pathogen. No internalization of E. coli O157:H7 occurred when lettuce leaves were inoculated with 4.4 log CFU per leaf, but it did occur when inoculated with 6.4 log CFU per leaf. Internalization was statistically greater when spinach leaves were inoculated on the abaxial (underside) than when inoculated on the adaxial (topside) side, and when the enteric pathogen was spread after surface inoculation. Brief exposure (∼18 h) of lettuce leaves to insects (5 cabbage loopers, 10 thrips, or 10 aphids) prior to inoculation with E. coli O157:H7 resulted in significantly reduced internalized populations of the pathogen within these leaves after approximately 2 weeks, as compared with leaves not exposed to insects. Surface-contaminated leaves physically injured through file abrasions also had significantly reduced populations of both total and internalized E. coli O157:H7 as compared with nonabraded leaves 2 weeks after pathogen exposure.

Contaminated Stream Water as Source for Escherichia coli O157 Illness in Children.

Science.gov (United States)

Probert, William S; Miller, Glen M; Ledin, Katya E

2017-07-01

In May 2016, an outbreak of Shiga toxin-producing Escherichia coli O157 infections occurred among children who had played in a stream flowing through a park. Analysis of E. coli isolates from the patients, stream water, and deer and coyote scat showed that feces from deer were the most likely source of contamination.

The occurrence of Escherichia coli O157:H7 in market and abattoir ...

African Journals Online (AJOL)

Escherichia coli O157:H7 is a newly emerging pathogen frequently associated with the consumption of foods of bovine origin. The severity of the infections caused by this food borne pathogen in the young and the elderly has had a tremendous impact on human health and food industry. The present study evaluated the ...

Immunization of pregnant cows with Shiga toxin-2 induces high levels of specific colostral antibodies and lactoferrin able to neutralize E. coli O157:H7 pathogenicity.

Science.gov (United States)

Albanese, Adriana; Sacerdoti, Flavia; Seyahian, E Abril; Amaral, Maria Marta; Fiorentino, Gabriela; Fernandez Brando, Romina; Vilte, Daniel A; Mercado, Elsa C; Palermo, Marina S; Cataldi, Angel; Zotta, Elsa; Ibarra, Cristina

2018-03-20

E. coli O157:H7 is a foodborne pathogen responsible for bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). The objective of the present work was to evaluate the ability of colostral IgG obtained from Stx2-immunized cows to prevent against E. coli O157:H7 infection and Stx2 cytotoxicity. Hyperimmune colostrum (HC) was obtained from cows intramuscularly immunized with inactivated Stx2 or vehicle for controls. Colostral IgG was purified by affinity chromatography. Specific IgG antibodies against Stx2 and bovine lactoferrin (bLF) levels in HC and the corresponding IgG (HC-IgG/bLF) were determined by ELISA. The protective effects of HC-IgG/bLF against Stx2 cytotoxicity and adhesion of E. coli O157:H7 and its Stx2-negative mutant were analyzed in HCT-8 cells. HC-IgG/bLF prevention against E. coli O157:H7 was studied in human colon and rat colon loops. Protection against a lethal dose of E. coli O157:H7 was evaluated in a weaned mice model. HC-IgG/bLF showed high anti-Stx2 titers and high bLF levels that were able to neutralize the cytotoxic effects of Stx2 in vitro and in vivo. Furthermore, HC-IgG/bLF avoided the inhibition of water absorption induced by E. coli O157:H7 in human colon and also the pathogenicity of E. coli O157:H7 and E. coli O157:H7Δstx2 in rat colon loops. Finally, HC-IgG/bLF prevented in a 100% the lethality caused by E. coli O157:H7 in a weaned mice model. Our study suggests that HC-IgG/bLF have protective effects against E. coli O157:H7 infection. These beneficial effects may be due to specific anti-Stx2 neutralizing antibodies in combination with high bLF levels. These results allow us to consider HC-IgG/bLF as a nutraceutical tool which could be used in combination with balanced supportive diets to prevent HUS. However further studies are required before recommendations can be made for therapeutic and clinical applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

Role of curli and contamination level on Escherichia coli O157:H7 internalization into organic spinach plants grown on hydroponics and in soil

Science.gov (United States)

Introduction: E. coli O157:H7 may be internalized into organic leafy greens via root uptake. Understanding the mechanisms of E. coli O157:H7 internalization into organic leafy greens is important as produce wash treatment may not remove internalized pathogens. Purpose: The internalization potential...

40 CFR 80.157 - Volumetric additive reconciliation (“VAR”), equipment calibration, and recordkeeping requirements.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Volumetric additive reconciliation (â... ADDITIVES Detergent Gasoline § 80.157 Volumetric additive reconciliation (“VAR”), equipment calibration, and... other comparable VAR supporting documentation. (ii) For a facility which uses a gauge to measure the...

Host cell interactions of outer membrane vesicle-associated virulence factors of enterohemorrhagic Escherichia coli O157: Intracellular delivery, trafficking and mechanisms of cell injury

Science.gov (United States)

Greune, Lilo; Jarosch, Kevin-André; Steil, Daniel; Zhang, Wenlan; He, Xiaohua; Lloubes, Roland; Fruth, Angelika; Kim, Kwang Sik; Schmidt, M. Alexander; Dobrindt, Ulrich; Mellmann, Alexander; Karch, Helge

2017-01-01

Outer membrane vesicles (OMVs) are important tools in bacterial virulence but their role in the pathogenesis of infections caused by enterohemorrhagic Escherichia coli (EHEC) O157, the leading cause of life-threatening hemolytic uremic syndrome, is poorly understood. Using proteomics, electron and confocal laser scanning microscopy, immunoblotting, and bioassays, we investigated OMVs secreted by EHEC O157 clinical isolates for virulence factors cargoes, interactions with pathogenetically relevant human cells, and mechanisms of cell injury. We demonstrate that O157 OMVs carry a cocktail of key virulence factors of EHEC O157 including Shiga toxin 2a (Stx2a), cytolethal distending toxin V (CdtV), EHEC hemolysin, and flagellin. The toxins are internalized by cells via dynamin-dependent endocytosis of OMVs and differentially separate from vesicles during intracellular trafficking. Stx2a and CdtV-B, the DNase-like CdtV subunit, separate from OMVs in early endosomes. Stx2a is trafficked, in association with its receptor globotriaosylceramide within detergent-resistant membranes, to the Golgi complex and the endoplasmic reticulum from where the catalytic Stx2a A1 fragment is translocated to the cytosol. CdtV-B is, after its retrograde transport to the endoplasmic reticulum, translocated to the nucleus to reach DNA. CdtV-A and CdtV-C subunits remain OMV-associated and are sorted with OMVs to lysosomes. EHEC hemolysin separates from OMVs in lysosomes and targets mitochondria. The OMV-delivered CdtV-B causes cellular DNA damage, which activates DNA damage responses leading to G2 cell cycle arrest. The arrested cells ultimately die of apoptosis induced by Stx2a and CdtV via caspase-9 activation. By demonstrating that naturally secreted EHEC O157 OMVs carry and deliver into cells a cocktail of biologically active virulence factors, thereby causing cell death, and by performing first comprehensive analysis of intracellular trafficking of OMVs and OMV-delivered virulence factors

Managing Salmonella Typhimurium and Escherichia coli O157:H7 in soil with hydrated lime - An outdoor study in lysimeters and field plots.

Science.gov (United States)

Nyberg, Karin A; Vinnerås, Björn; Albihn, Ann

2014-01-01

An outbreak of Salmonella Typhimurium or E. coli O157:H7 among domestic animals can have great financial consequences for an animal enterprise but also be a threat for public health as there is a risk for transmission of the infection through the environment. In order to minimize disease transmission, it is important to treat not only the affected animals but also the areas on which they have been kept. In the present study, the effect of hydrated lime as a treatment for Salmonella Typhimurium or E. coli O157:H7 contaminated soil was investigated. The study was performed outdoors, in a lysimeter system and in field plots. The soils were spiked with Salmonella Typhimurium and/or E. coli O157:H7 and hydrated lime was added at three different concentrations (0.5, 1 and 2%). Sampling was performed over one month, and the levels of bacteria were analyzed by standard culture methods. In addition, the soil pH was monitored throughout the study. The results showed that application of 0.5-1 kg hydrated lime per m(2) reduced both Salmonella Typhimurium and E. coli O157:H7 numbers to below the detection limit (2 log10 CFU g-1 soil) in 3-7 days. Lower application rates of hydrated lime did not reduce pathogen numbers in the lysimeter study, but in the field plots no E. coli O157:H7 was detected at the end of the four-week study period regardless of hydrated lime application. A recommended strategy for treating a Salmonella Typhimurium or E. coli O157:H7 contaminated soil could therefore be to monitor the pH over the time of treatment and to repeat hydrated lime application if a decrease in pH is observed.

Aptasensors for rapid detection of Escherichia coli O157:H7 and Salmonella typhimurium

Science.gov (United States)

Wu, Wen-he; Li, Min; Wang, Yue; Ouyang, Hou-xian; Wang, Lin; Li, Ci-xiu; Cao, Yu-chen; Meng, Qing-he; Lu, Jian-xin

2012-11-01

Herein we reported the development of aptamer-based biosensors (aptasensors) based on label-free aptamers and gold nanoparticles (AuNPs) for detection of Escherichia coli ( E. coli) O157:H7 and Salmonella typhimurium. Target bacteria binding aptamers are adsorbed on the surface of unmodified AuNPs to capture target bacteria, and the detection was accomplished by target bacteria-induced aggregation of the aptasensor which is associated as red-to-purple color change upon high-salt conditions. By employing anti- E. coli O157:H7 aptamer and anti- S. typhimurium aptamer, we developed a convenient and rapid approach that could selectively detect bacteria without specialized instrumentation and pretreatment steps such as cell lysis. The aptasensor could detect as low as 105colony-forming units (CFU)/ml target bacteria within 20 min or less and its specificity was 100%. This novel method has a great potential application in rapid detection of bacteria in the near future.

Identifying mechanisms by which Escherichia coli O157:H7 subverts interferon-γ mediated signal transducer and activator of transcription-1 activation.

Directory of Open Access Journals (Sweden)

Nathan K Ho

Full Text Available Enterohemorrhagic Escherichia coli serotype O157:H7 is a food borne enteric bacterial pathogen that causes significant morbidity and mortality in both developing and industrialized nations. E. coli O157:H7 infection of host epithelial cells inhibits the interferon gamma pro-inflammatory signaling pathway, which is important for host defense against microbial pathogens, through the inhibition of Stat-1 tyrosine phosphorylation. The aim of this study was to determine which bacterial factors are involved in the inhibition of Stat-1 tyrosine phosphorylation. Human epithelial cells were challenged with either live bacteria or bacterial-derived culture supernatants, stimulated with interferon-gamma, and epithelial cell protein extracts were then analyzed by immunoblotting. The results show that Stat-1 tyrosine phosphorylation was inhibited by E. coli O157:H7 secreted proteins. Using sequential anion exchange and size exclusion chromatography, YodA was identified, but not confirmed to mediate subversion of the Stat-1 signaling pathway using isogenic mutants. We conclude that E. coli O157:H7 subverts Stat-1 tyrosine phosphorylation in response to interferon-gamma through a still as yet unidentified secreted bacterial protein.

Inactivation of Escherichia coli O157:H7, salmonellae, and Campylobacter jejuni in raw ground beef by gamma irradiation

International Nuclear Information System (INIS)

Clavero, M.R.S.; Monk, J.D.; Beuchat, L.R.; Doyle, M.P.; Brackett, R.E.

1994-01-01

Raw ground beef patties inoculated with stationary-phase cells of Escherichia coli O157:H7, salmonellae, or Campylobacter jejuni were subjected to gamma irradiation (60Co) treatment, with doses ranging from 0 to 2.52 kGy. The influence of two levels of fat (8 to 14% [low fat] and 27 to 28% [high fat]) and temperature (frozen [-17 to -15 degrees C] and refrigerated [3 to 5 degrees C]) on the inactivation of each pathogen by irradiation was investigated. In ascending order of irradiation resistance, the D10 values ranged from 0.175 to 0.235 kGy (C. jejuni), from 0.241 to 0.307 kGy (E. coli O157:H7), and from 0.618 to 0.800 kGy (salmonellae). Statistical analysis revealed that E. coli O157:H7 had a significantly (P 0.05) higher D10 value when irradiated at -17 to -15 degrees C than when irradiated at 3 to 5 degrees C. Regardless of the temperature during irradiation, the level of fat did not have a significant effect on the D10 value. Salmonellae behaved like E. coli O157:H7 in low-fat beef, but temperature did not have a significant effect when the pathogen was irradiated in high-fat ground beef. Significantly higher D10 values were calculated for C. jejuni irradiated in frozen than in refrigerated low-fat beef. C. jejuni was more resistant to irradiation in low-fat beef than in high-fat beef when treatment was at -17 to -15 degrees C. Regardless of the fat level and temperature during inactivation, these pathogens were highly sensitive to gamma irradiation. An applied dose of 2.5 kGy would be sufficient to kill 10(8.1) E. coli O157:H7, 10(3.1) salmonellae, and 10(10.6) C. jejuni, resulting in a high probability of complete inactivation of populations much higher than those occasionally present in ground beef patties

A rapid and highly sensitive protocol for the detection of Escherichia coli O157:H7 based on immunochromatography assay combined with the enrichment technique of immunomagnetic nanoparticles

Directory of Open Access Journals (Sweden)

Qi H

2011-11-01

Full Text Available Hui Qi1, Zhen Zhong1, Han-Xin Zhou1, Chun-Yan Deng1, Hai Zhu2, Jin-Feng Li2, Xi-Li Wang2, Fu-Rong Li1,31Clinical Medical Research Center, The Second Clinical Medical College (Shenzhen People's Hospital, Jinan University, 2Shenzhen Bioeasy Biotechnologies Co, Ltd, 3Shenzhen Institute of Gerontology, Shenzhen, People's Republic of ChinaBackground: Escherichia coli O157:H7 (E. coli O157:H7 is an important pathogenic bacterium that threatens human health. A rapid, simple, highly sensitive, and specific method for the detection of E. coli O157:H7 is necessary.Methods: In the present study, immunomagnetic nanoparticles (IMPs were prepared with nanopure iron as the core, coated with E. coli O157:H7 polyclonal antibodies. These IMPs were used in combination with immunochromatographic assay (ICA and used to establish highly sensitive and rapid kits (IMPs+ICA to detect E. coli O157:H7. The kits were then used to detect E. coli O157:H7 in 150 food samples and were compared with conventional ICA to evaluate their efficacy.Results: The average diameter of IMPs was 56 nm and the amount of adsorbed antibodies was 106.0 µg/mg. The sensitivity of ICA and IMPs+ICA was 105 colony-forming units/mL and 103 CFUs/mL, respectively, for purified E. coli O157:H7 solution. The sensitivity of IMPs+ICA was increased by two orders, and its specificity was similar to ICA.Conclusion: The kits have the potential to offer important social and economic benefits in the screening, monitoring, and control of food safety.Keywords: colloidal gold, immunomagnetic nanoparticles, Escherichia coli O157:H7, immunochromatographic assay

Longitudinal study of two Irish dairy herds: Low numbers of of Shiga toxin-producing Escherichia coli O157 and O26 super-shedders identified

Directory of Open Access Journals (Sweden)

Brenda Patricia Murphy

2016-11-01

Full Text Available A 12-month longitudinal study was undertaken on two dairy herds to ascertain the Shiga-toxin producing Escherichia coli (STEC O157 and O26 shedding status of the animals and its impact (if any on raw milk. Cattle are a recognised reservoir for these organisms with associated public health and environmental implications. Animals shedding E. coli O157 at >10,000 CFU/g of faeces have been deemed super-shedders. There is a gap in the knowledge regarding super-shedding of other STEC serogroups. A cohort of 40 lactating cows from herds previously identified as positive for VTEC in a national surveillance project were sampled every second month between August, 2013 and July, 2014. Metadata on any potential super-shedders was documented including e.g. age of the animal, number of lactations and days in lactation, nutritional condition, somatic cell count and content of protein in milk to assess if any were associated with risk factors for super-shedding. Recto-anal mucosal swabs, raw milk, milk filters and water samples were procured for each herd. The swabs were examined for E. coli O157 and O26 using a quantitative real time PCR method. Counts (CFU swab-1 were obtained from a standard calibration curve that related real-time PCR cycle threshold (Ct values against the initial concentration of O157 or O26 in the samples. Results from Farm A: 305 animals were analysed; 15 E. coli O157 (5% were recovered, 13 were denoted STEC encoding either stx1 and/or stx2 virulence genes and 5 (2% STEC O26 were recovered. One super-shedder was identified shedding STEC O26 (stx1&2. Farm B: 224 animals were analysed; eight E. coli O157 (3.5% were recovered (seven were STEC and 9 (4% STEC O26 were recovered. Three super-shedders were identified, one was shedding STEC O157 (stx2 and two STEC O26 (stx2. Three encoded the adhering and effacement gene (eae and one isolate additionally encoded the haemolysin gene (hlyA. The results of this study show, low numbers of super

Electrochemical immunosensor assay (EIA) for sensitive detection of E. coli O157:H7 with signal amplification on a SG-PEDOT-AuNPs electrode interface.

Science.gov (United States)

Guo, Yuna; Wang, Yu; Liu, Su; Yu, Jinghua; Wang, Hongzhi; Cui, Min; Huang, Jiadong

2015-01-21

A novel electrochemical immunosensor assay (EIA) for highly sensitive and specific detection of Escherichia coli O157:H7 has been developed. This immunosensor is constructed by the assembly of capture antibody on SG-PEDOT-AuNPs composites modified glass carbon electrode. In the presence of target E. coli O157:H7, horseradish peroxidase (HRP)-labeled antibody is captured on the electrode surface to form a sandwich-type system via the specific identification. As a result, E. coli O157:H7 detection is realized by outputting a redox current from electro-reduction of hydrogen peroxide reaction catalyzed by HRP. In our assay, the combination of the unique properties of sulfonated graphene (SG) and gold nanoparticles (AuNPs) can not only accelerate electron transfer on electrode interface, but also provide an excellent scaffold for the conjugation of capture antibody that significantly improves the target capture efficiency and enhances the sensitivity of the biosensor. The results reveal the calibration plot obtained for E. coli O157:H7 is approximately linear from 7.8 × 10-7.8 × 10(6) colony-forming unit (cfu) mL(-1) with the limit of detection of 3.4 × 10 cfu mL(-1). In addition, the biosensor has been successfully applied to the quantitative assay of E. coli O157:H7 in synthetic samples (spring water and milk). Hence, the developed electrochemical-based immunosensor might provide a useful and practical tool for E. coli O157:H7 determination and related food safety analysis and clinical diagnosis.

House Flies in the Confined Cattle Environment Carry Non-O157 Shiga Toxin-Producing Escherichia coli.

Science.gov (United States)

Puri-Giri, R; Ghosh, A; Thomson, J L; Zurek, L

2017-05-01

Cattle manure is one of the primary larval developmental habitats of house flies, Musca domestica (L.). Cattle serve as asymptomatic reservoirs of Shiga toxin-producing Escherichia coli (STEC), and bacteria are released into the environment in cattle feces. The USDA-FSIS declared seven STEC serogroups (O157, O26, O45, O103, O145, O121, and O111) as adulterants in beef products. In addition, the serogroup O104 was a culprit of a large outbreak in Germany in 2011. Our study aimed to assess the prevalence of seven non-O157 STEC (O26, O45, O145, O103, O121, O111, and O104) serogroups in adult house flies. Flies (n = 463) were collected from nine feedlots and three dairy farms in six states in the United States and individually processed. This involved a culturing approach with immunomagnetic separation followed by multiplex polymerase chain reactions for detection of individual serogroups and virulence traits. The concentration of bacteria on modified Possé agar ranged between 1.0 × 101 and 7.0 × 107 (mean: 1.5 ± 0.3 × 106) CFU/fly. Out of 463 house flies, 159 (34.3%) carried one or more of six E. coli serogroups of interest. However, STEC was found in 1.5% of house flies from feedlots only. These were E. coli O103 and O104 harboring stx1 and ehxA and E. coli O45 with stx1, eae, and ehxA. This is the first study reporting the isolation of non-O157 STEC in house flies from the confined cattle environment and indicating a potential role of this insect as a vector and reservoir of non-O157 STEC in confined beef cattle. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Diversity of Survival Patterns among Escherichia coli O157:H7 Genotypes Subjected to Food-Related Stress Conditions.

Science.gov (United States)

Elhadidy, Mohamed; Álvarez-Ordóñez, Avelino

2016-01-01

The purpose of this study was to evaluate the resistance patterns to food-related stresses of Shiga toxin producing Escherichia coli O157:H7 strains belonging to specific genotypes. A total of 33 E. coli O157:H7 strains were exposed to seven different stress conditions acting as potential selective pressures affecting the transmission of E. coli O157:H7 to humans through the food chain. These stress conditions included cold, oxidative, osmotic, acid, heat, freeze-thaw, and starvation stresses. The genotypes used for comparison included lineage-specific polymorphism, Shiga-toxin-encoding bacteriophage insertion sites, clade type, tir (A255T) polymorphism, Shiga toxin 2 subtype, and antiterminator Q gene allele. Bacterial resistance to different stressors was calculated by determining D-values (times required for inactivation of 90% of the bacterial population), which were then subjected to univariate and multivariate analyses. In addition, a relative stress resistance value, integrating resistance values to all tested stressors, was calculated for each bacterial strain and allowed for a ranking-type classification of E. coli O157:H7 strains according to their environmental robustness. Lineage I/II strains were found to be significantly more resistant to acid, cold, and starvation stress than lineage II strains. Similarly, tir (255T) and clade 8 encoding strains were significantly more resistant to acid, heat, cold, and starvation stress than tir (255A) and non-clade 8 strains. Principal component analysis, which allows grouping of strains with similar stress survival characteristics, separated strains of lineage I and I/II from strains of lineage II, which in general showed reduced survival abilities. Results obtained suggest that lineage I/II, tir (255T), and clade 8 strains, which have been previously reported to be more frequently associated with human disease cases, have greater multiple stress resistance than strains of other genotypes. The results from this

DETECCIÓN DE Escherichia coli O157: H7 y Salmonella spp., EN CERDOS DEL DEPARTAMENTO DE CORDOBA

Directory of Open Access Journals (Sweden)

Jaime Vargas

2004-07-01

Full Text Available E. coli O157:H7 y Salmonella spp., son bacterias de distribución mundial causantes de enfermedades intestinales queafectan tanto al hombre como a LOS animales. ESTE estudio tuvo como objetivo determinar la presencia y frecuenciade aparición de E. coli O157:H7 y Salmonella spp., en los diferentes sistemas de producción porcina que se empleanen el departamento de Córdoba. Se realizó un estudio de corte descriptivo prospectivo, con un muestreo al azar enlos sistemas de explotación porcina intensiva y extensiva. Se procesaron 500 muestras de materia fecal de porcinos,250 provenientes del sistema extensivo y 250 del sistema intensivo. Para la detección E. coli y Salmonella spp., sellevaron a cabo procedimientos estándares microbiológicos. Los resultados mostraron una frecuencia de aparición deSalmonella spp., del 1%, el 0.2% en el sistema intensivo y el 0.8% en el sistema extensivo; no se aisló Escherichia coliO157:H7. Los resultados de resistencia y sensibilidad a los antibióticos en las cepas aisladas de Salmonella spp.,mostraron una sensibilidad del 100% al trimetoprim sulfametozasol, a la amikacina, al ceftriaxona, a la ciprofloxacina,a la gentamicina y al aztreonam y un 20% a la ampicilina y al sulbactam. Se concluye que la frecuencia de apariciónde Salmonella spp., en muestras coprológicas porcinas es baja, y nula para E. coli O157:H7, sin embargo, se debemantener la vigilancia sobre estos patógenos, por lo que se recomienda continuar los estudios epidemiológicos.

Green fluorescent protein labeling of Listeria, Salmonella, and Escherichia coli O157:H7 for safety-related studies.

Directory of Open Access Journals (Sweden)

Li Ma

Full Text Available Many food safety-related studies require tracking of introduced foodborne pathogens to monitor their fate in complex environments. The green fluorescent protein (GFP gene (gfp provides an easily detectable phenotype so has been used to label many microorganisms for ecological studies. The objectives of this study were to label major foodborne pathogens and related bacteria, including Listeria monocytogenes, Listeria innocua, Salmonella, and Escherichia coli O157:H7 strains, with GFP and characterize the labeled strains for stability of the GFP plasmid and the plasmid's effect on bacterial growth. GFP plasmids were introduced into these strains by a CaCl(2 procedure, conjugation or electroporation. Stability of the label was determined through sequential propagation of labeled strains in the absence of selective pressure, and rates of plasmid-loss were calculated. Stability of the GFP plasmid varied among the labeled species and strains, with the most stable GFP label observed in E. coli O157:H7. When grown in nonselective media for two consecutive subcultures (ca. 20 generations, the rates of plasmid loss among labeled E. coli O157:H7, Salmonella and Listeria strains ranged from 0%-30%, 15.8%-99.9% and 8.1%-93.4%, respectively. Complete loss (>99.99% of the plasmid occurred in some labeled strains after five consecutive subcultures in the absence of selective pressure, whereas it remained stable in others. The GFP plasmid had an insignificant effect on growth of most labeled strains. E. coli O157:H7, Salmonella and Listeria strains can be effectively labeled with the GFP plasmid which can be stable in some isolates for many generations without adversely affecting growth rates.

Shiga toxin-producing Escherichia coli (STEC) O22:H8 isolated from cattle reduces E. coli O157:H7 adherence in vitro and in vivo.

Science.gov (United States)

Martorelli, L; Albanese, A; Vilte, D; Cantet, R; Bentancor, A; Zolezzi, G; Chinen, I; Ibarra, C; Rivas, M; Mercado, E C; Cataldi, A

2017-09-01

Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria responsible for food-associated diseases. Clinical features include a wide range of symptoms such as diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome (HUS), a life-threatening condition. Our group has observed that animals naturally colonized with STEC strains of unknown serotype were not efficiently colonized with E. coli O157:H7 after experimental infection. In order to assess the basis of the interference, three STEC strains were isolated from STEC persistently-colonized healthy cattle from a dairy farm in Buenos Aires, Argentina. The three isolated strains are E. coli O22:H8 and carry the stx1 and stx2d genes. The activatable activity of Stx2d was demonstrated in vitro. The three strains carry the adhesins iha, ehaA and lpf O113 . E. coli O22:H8 formed stronger biofilms in abiotic surface than E. coli O157:H7 (eae+, stx2+) and displayed a more adherent phenotype in vitro towards HeLa cells. Furthermore, when both serotypes were cultured together O22:H8 could reduce O157:H7 adherence in vitro. When calves were intragastrically pre-challenged with 10 8 CFU of a mixture of the three STEC strains and two days later challenged with the same dose of the strain E. coli O157:H7 438/99, the shedding of the pathogen was significantly reduced. These results suggest that E. coli O22:H8, a serotype rarely associated with human illness, might compete with O157:H7 at the bovine recto-anal junction, making non-O157 carrying-calves less susceptible to O157:H7 colonization and shedding of the bacteria to the environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Detection of viable but non-culturable Escherichia coli O157:H7 by PCR in combination with propidium monoazide.

Science.gov (United States)

Zhong, Junliang; Zhao, Xihong

2018-01-01

The aim of this study was to evaluate the applicability of the conventional PCR detection method combined with propidium monoazide (PMA) treatment for the detection of viable but non-culturable (VBNC) state Escherichia coli O157:H7 in ground beef meatballs. Under low temperature, E. coli O157:H7 cells were induced into the VBNC state in ground beef meatballs at - 20 °C after 152 days. The optimal PMA concentration of 5 µg/mL was obtained in beef meatball samples, which could completely inhibit the DNA amplification on dead cells (10 6  cells/mL) but with no inhibition on viable cells. The established PMA-PCR assay revealed that the VBNC counts exceeded 10 7  CFU/mL in artificial contamination beef samples, which could be used for semi-quantitative detection of VBNC cells in beef meatball samples. This study indicated that the PMA-PCR assay might be a potential method for detection of VBNC state E . coli O157:H7 cells in food products.

Graphene-interfaced electrical biosensor for label-free and sensitive detection of foodborne pathogenic E. coli O157:H7.

Science.gov (United States)

Pandey, Ashish; Gurbuz, Yasar; Ozguz, Volkan; Niazi, Javed H; Qureshi, Anjum

2017-05-15

E. coli O157:H7 is an enterohemorrhagic bacteria responsible for serious foodborne outbreaks that causes diarrhoea, fever and vomiting in humans. Recent foodborne E. coli outbreaks has left a serious concern to public health. Therefore, there is an increasing demand for a simple, rapid and sensitive method for pathogen detection in contaminated foods. In this study, we developed a label-free electrical biosensor interfaced with graphene for sensitive detection of pathogenic bacteria. This biosensor was fabricated by interfacing graphene with interdigitated microelectrodes of capacitors that were biofunctionalized with E. coli O157:H7 specific antibodies for sensitive pathogenic bacteria detection. Here, graphene nanostructures on the sensor surface provided superior chemical properties such as high carrier mobility and biocompatibility with antibodies and bacteria. The sensors transduced the signal based on changes in dielectric properties (capacitance) through (i) polarization of captured cell-surface charges, (ii) cells' internal bioactivity, (iii) cell-wall's electronegativity or dipole moment and their relaxation and (iv) charge carrier mobility of graphene that modulated the electrical properties once the pathogenic E. coli O157:H7 captured on the sensor surface. Sensitive capacitance changes thus observed with graphene based capacitors were specific to E. coli O157:H7 strain with a sensitivity as low as 10-100 cells/ml. The proposed graphene based electrical biosensor provided advantages of speed, sensitivity, specificity and in-situ bacterial detection with no chemical mediators, represents a versatile approach for detection of a wide variety of other pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

Colorimetry of the diffuse nebulas S 156, S 157A, S 158, and NGC 7635

International Nuclear Information System (INIS)

Parsamian, E.S.; Petrosian, V.M.

1984-01-01

The results of a colorimetric investigation of the diffuse nebulas S 156, S 157A, S 158, and NGC 7635, which are excited by O stars, are presented. The nebulas S 156, S 157A, and NGC 7635 are very bright in U due to the presence in them of strong ultraviolet doublet forbidden O II 3727 A. These values correspond effectively to the monochromatic image of the nebulas at this wavelength. The measurements show that the B-V color index does not change significantly with distance from the star except for S 158, where a weak dependence is observed. The results indicate that the physical properties of these nebulas differ little. It is concluded that the gas masses in this association are remnants of star formation that have a common origin with the stars. The age of the association is estimated at 100,000-1,000,000 yr. 13 references

Quantitative Microbial Risk Assessment for Escherichia coli O157:H7 in Fresh-Cut Lettuce.

Science.gov (United States)

Pang, Hao; Lambertini, Elisabetta; Buchanan, Robert L; Schaffner, Donald W; Pradhan, Abani K

2017-02-01

Leafy green vegetables, including lettuce, are recognized as potential vehicles for foodborne pathogens such as Escherichia coli O157:H7. Fresh-cut lettuce is potentially at high risk of causing foodborne illnesses, as it is generally consumed without cooking. Quantitative microbial risk assessments (QMRAs) are gaining more attention as an effective tool to assess and control potential risks associated with foodborne pathogens. This study developed a QMRA model for E. coli O157:H7 in fresh-cut lettuce and evaluated the effects of different potential intervention strategies on the reduction of public health risks. The fresh-cut lettuce production and supply chain was modeled from field production, with both irrigation water and soil as initial contamination sources, to consumption at home. The baseline model (with no interventions) predicted a mean probability of 1 illness per 10 million servings and a mean of 2,160 illness cases per year in the United States. All intervention strategies evaluated (chlorine, ultrasound and organic acid, irradiation, bacteriophage, and consumer washing) significantly reduced the estimated mean number of illness cases when compared with the baseline model prediction (from 11.4- to 17.9-fold reduction). Sensitivity analyses indicated that retail and home storage temperature were the most important factors affecting the predicted number of illness cases. The developed QMRA model provided a framework for estimating risk associated with consumption of E. coli O157:H7-contaminated fresh-cut lettuce and can guide the evaluation and development of intervention strategies aimed at reducing such risk.

Hosing Instability of the Drive Electron Beam in the E157 Plasma-Wakefield Acceleration Experiment at the Stanford Linear Accelerator

International Nuclear Information System (INIS)

Blue, Brent Edward

2005-01-01

In the plasma-wakefield experiment at SLAC, known as E157, an ultra-relativistic electron beam is used to both excite and witness a plasma wave for advanced accelerator applications. If the beam is tilted, then it will undergo transverse oscillations inside of the plasma. These oscillations can grow exponentially via an instability know as the electron hose instability. The linear theory of electron-hose instability in a uniform ion column predicts that for the parameters of the E157 experiment (beam charge, bunch length, and plasma density) a growth of the centroid offset should occur. Analysis of the E157 data has provided four critical results. The first was that the incoming beam did have a tilt. The tilt was much smaller than the radius and was measured to be 5.3 (micro)m/(delta) z at the entrance of the plasma (IP1.) The second was the beam centroid oscillates in the ion channel at half the frequency of the beam radius (betatron beam oscillations), and these oscillations can be predicted by the envelope equation. Third, up to the maximum operating plasma density of E157 (∼2 x 10 14 cm -3 ), no growth of the centroid offset was measured. Finally, time-resolved data of the beam shows that up to this density, no significant growth of the tail of the beam (up to 8ps from the centroid) occurred even though the beam had an initial tilt

Hosing Instability of the Drive Electron Beam in the E157 Plasma-Wakefield Acceleration Experiment at the Stanford Linear Accelerator

Energy Technology Data Exchange (ETDEWEB)

Blue, Brent Edward; /SLAC /UCLA

2005-10-10

In the plasma-wakefield experiment at SLAC, known as E157, an ultra-relativistic electron beam is used to both excite and witness a plasma wave for advanced accelerator applications. If the beam is tilted, then it will undergo transverse oscillations inside of the plasma. These oscillations can grow exponentially via an instability know as the electron hose instability. The linear theory of electron-hose instability in a uniform ion column predicts that for the parameters of the E157 experiment (beam charge, bunch length, and plasma density) a growth of the centroid offset should occur. Analysis of the E157 data has provided four critical results. The first was that the incoming beam did have a tilt. The tilt was much smaller than the radius and was measured to be 5.3 {micro}m/{delta}{sub z} at the entrance of the plasma (IP1.) The second was the beam centroid oscillates in the ion channel at half the frequency of the beam radius (betatron beam oscillations), and these oscillations can be predicted by the envelope equation. Third, up to the maximum operating plasma density of E157 ({approx}2 x 10{sup 14} cm{sup -3}), no growth of the centroid offset was measured. Finally, time-resolved data of the beam shows that up to this density, no significant growth of the tail of the beam (up to 8ps from the centroid) occurred even though the beam had an initial tilt.

Escherichia coli O157:H7 converts plant-derived choline to glycine betaine for osmoprotection during pre- and post-harvest colonization of injured lettuce leaves

Science.gov (United States)

The opportunistic colonization of damaged plant tissue by human enteric pathogens may contribute to the occurrence of outbreaks of foodborne illness linked to produce. E. coli O157:H7 (EcO157) responds to physicochemical stresses in cut lettuce and lettuce lysates by upregulation of several stress r...

Proliferation of Escherichia coli O157:H7 in soil and hydroponic microgreen production systems

Science.gov (United States)

Radish (Raphanus sativus var. longipinnatus) microgreens were produced from seeds inoculated with Escherichia coli O157: H7 using soil substitute and hydroponic production systems. E. coli populations on the edible and inedible parts of harvested microgreen plants and in growth medium were examined....

Validation of low-volume enrichment protocols for detection of Escherichia coli O157 in raw ground beef components, using commercial kits.

Science.gov (United States)

Ahmed, Imtiaz; Hughes, Denise; Jenson, Ian; Karalis, Tass

2009-03-01

Testing of beef destined for use in ground beef products for the presence of Escherichia coli O157:H7 has become an important cornerstone of control and verification activities within many meat supply chains. Validation of the ability of methods to detect low levels of E. coli O157:H7 is critical to confidence in test systems. Many rapid methods have been validated against standard cultural methods for 25-g samples. In this study, a number of previously validated enrichment broths and commercially available test kits were validated for the detection of low numbers of E. coli O157:H7 in 375-g samples of raw ground beef component matrices using 1 liter of enrichment broth (large-sample:low-volume enrichment protocol). Standard AOAC International methods for 25-g samples in 225 ml of enrichment broth, using the same media, incubation conditions, and test kits, were used as reference methods. No significant differences were detected in the ability of any of the tests to detect low levels of E. coli O157:H7 in samples of raw ground beef components when enriched according to standard or large-sample:low-volume enrichment protocols. The use of large-sample:low-volume enrichment protocols provides cost savings for media and logistical benefits when handling and incubating large numbers of samples.

A novel approach to investigate the uptake and internalization of Escherichia coli O157:H7 in spinach cultivated in soil and hydroponic media

Science.gov (United States)

Internalization of E. coli O157:H7 into spinach plants through root uptake is a potential route of contamination. A Tn7-based plasmid vector was used to insert the green fluorescent protein (gfp) gene into the attTn7 site in the E. coli chromosome. Three gfp-labeled E. coli inocula, O157:H7 strains ...

Prevalencia y resistencia a antibióticos de Escherichia coli O157:H7 aislada de canales de bovinos sacrificados en rastros del altiplano central Mexicano

Directory of Open Access Journals (Sweden)

Nydia Edith Reyes-Rodríguez

2013-01-01

Full Text Available La carne es el principal vehículo de toxiinfecciones alimentarias como consecuencia de una higiene deficiente en el sacrificio de los animales o durante el manejo de las canales. En este estudio se analizaron tres rastros municipales del Altiplano Central Mexicano, de los cuales se obtuvieron 228 muestras pareadas de canal (n=114 y contenido de colon (n=114 de bovinos que fueron sacrificados en estos rastros; se obtuvieron 2 (0.8 % cepas de E. coli O157:NM a partir de contenido de colon y 6 (2.6 % cepas de E. coli O157:H7 (5 de canales y 1 de contenido de colon. El porcentaje de aislamiento de cada rastro fue variable, encontrando diferencias significativas ( P <0.05. En las cepas de E. coli O157:NM y O157:H7 se observa que la resistencia más alta fue para cefalotina con un 75 %, carbencilina con 62.5 %, amikacina con 50 % y gentamicina con 50 %, el 16.7 % de las cepas de E. coli O157:H7 presentaron los geneseae , stx1 y stx2 y el 66.7 % los gen eae y stx2 . En conclusión los resultados obtenidos muestra la presencia E. coli O157:H7 con factores de virulencia y resistencia a antibióticos, en canales de bovinos de rastros del altiplano central Mexicano, considerándose una fuente de contaminación importante y un riesgo para la salud pública.

Do we really observe a bow shock in N157B...?

OpenAIRE

van der Swaluw, Eric

2003-01-01

I present a model of a pulsar wind interacting with its associated supernova remnant. I will use the model to argue that one can explain the morphology of the pulsar wind nebula inside N157B, a supernova remnant in the Large Magellanic Cloud, without the need for a bow shock interpretation. The model uses a hydrodynamics code which simulates the evolution of a pulsar wind nebula, when the pulsar is moving at a high velocity (1000 km/sec) through the expanding supernova remnant. The simulation...

Aislamiento y caracterización de Escherichia coliO157:H7 a partir de carne molida de bovino en Lima-Perú

Directory of Open Access Journals (Sweden)

Carmen R. Méndez

2013-12-01

Full Text Available El objetivo del estudio fue aislar y caracterizar E. coliO157:H7 a partir de carne molida fresca de bovino obtenida en diferentes mercados de abastos. Se analizaron 195 muestras; para el aislamiento y enumeración de E. coli se utilizó la técnica del Numero Más probable mediante tubos múltiples; para el aislamiento y caracterización de E. coliO157:H7 el enriquecimiento selectivo y el análisis bioquímico, las colonias características se confirmaron mediante pruebas serológicas. Para determinar la presencia de shigatoxina (stx1, stx2 e intimina (eae A se empleó la técnica de PCR multiplex en tiempo real y para enterohemolisina la prueba de hemólisis. El 87.18% de la muestras fue positivo para E. coliy el 77.95% presentó un recuento igual o superior a 50 NMP/g. Se obtuvieron 3 (1.54% cepas de E. coliO157:H7, una stx1 +/ stx2 +/ eaeA – y enterohemolisina -, una stx1 +/ stx2 -/ eaeA + y enterohemolisina – y la otra stx1 -/ stx2 -/ eaeA – y enterohemolisina +. También se obtuvieron 4 cepas (2.05% de E. coli O157 no H7, ninguna presentó factores de virulencia. El estudio reveló el riesgo potencial de que E. coliO157:H7 afecte a la población de Lima.

Effects of Plant-Derived Extracts, Other Antimicrobials, and Their Combinations against Escherichia coli O157:H7 in Beef Systems.

Science.gov (United States)

Ko, Kyung Yuk; Geornaras, Ifigenia; Paik, Hyun-Dong; Kim, Kee-Tae; Sofos, John N

2015-06-01

The antimicrobial effects of thyme oil (TO), grapefruit seed extract (GSE), and basil essential oil, alone or in combination with cetylpyridinium chloride (CPC), sodium diacetate, or lactic acid, were evaluated against Escherichia coli O157:H7 in a moisture-enhanced beef model system. The model system was composed of a nonsterile beef homogenate to which NaCl (0.5%) and sodium tripolyphosphate (0.25%) were added, together with the tested antimicrobial ingredients. Beef homogenate treatments were inoculated (ca. 3 log CFU/ml) with rifampin-resistant E. coli O157:H7 (eight-strain mixture) and incubated at 15 °C (48 h). The most effective individual treatments were TO (0.25 or 0.5%) and GSE (0.5 or 1.0%), which immediately reduced (P extracts with CPC (0.02 or 0.04%) and sodium diacetate (0.25%) had an additive effect with respect to antibacterial activity. In a second study, antimicrobial interventions were evaluated for their efficacy in reducing surface contamination of E. coli O157:H7 on beef cuts and to determine the effect of these surface treatments on subsequent internalization of the pathogen during blade tenderization. Beef cuts (10 by 8 by 3.5 cm) were inoculated (ca. 4 log CFU/g) on one side with the rifampin-resistant E. coli O157:H7 strain mixture and were then spray treated (20 lb/in(2), 10 s) with water, GSE (5 and 10%), lactic acid (5%), or CPC (5%). Untreated (control) and spray-treated surfaces were then subjected to double-pass blade tenderization. Surface contamination (4.4 log CFU/g) of E. coli O157:H7 was reduced (P < 0.05) to 3.4 (5% CPC) to 4.1 (water or 5% GSE) log CFU/g following spray treatment. The highest and lowest transfer rates of pathogen cells from the surface to deeper tissues of blade-tenderized sections were obtained in the untreated control and CPC-treated samples, respectively.

33 CFR Appendix G to Part 157 - Timetables for Application of Double Hull Requirements

Science.gov (United States)

2010-07-01

... Double Hull Requirements G Appendix G to Part 157 Navigation and Navigable Waters COAST GUARD, DEPARTMENT... Application of Double Hull Requirements 1. Source. These timetables conform to 46 U.S.C. 3703a(c). 2... double hull or with a double containment system determined by the Coast Guard to be as effective as a...

Toward Development of an Oral, Plant-Based Vaccine Against Escherichia coli O157:H7

National Research Council Canada - National Science Library

Judge, Nicole A

2004-01-01

...), is the primary cause of acute renal failure in children in the U.S. The majority of U.S. cases of EHEC O157:H7 have occurred as a consequence of ingestion of undercooked, contaminated hamburger or produce and/or water contaminated with bovine manure...

The genome and proteome of a virulent Escherichia coli O157:H7 bacteriophage closely resembling Salmonella phage Felix O1

Directory of Open Access Journals (Sweden)

Waddell Thomas E

2009-04-01

Full Text Available Abstract Based upon whole genome and proteome analysis, Escherichia coli O157:H7-specific bacteriophage (phage wV8 belongs to the new myoviral genus, "the Felix O1-like viruses" along with Salmonella phage Felix O1 and Erwinia amylovora phage φEa21-4. The genome characteristics of phage wV8 (size 88.49 kb, mol%G+C 38.9, 138 ORFs, 23 tRNAs are very similar to those of phage Felix O1 (86.16 kb, 39.0 mol%G+C, 131 ORFs and 22 tRNAs and, indeed most of the proteins have their closest homologs within Felix O1. Approximately one-half of the Escherichia coli O157:H7 mutants resistant to phage wV8 still serotype as O157:H7 indicating that this phage may recognize, like coliphage T4, two different surface receptors: lipopolysaccharide and, perhaps, an outer membrane protein.

General outbreaks of vero cytotoxin producing Escherichia coli O157 in England and Wales from 1992 to 1994.

LENUS (Irish Health Repository)

Wall, P G

1996-02-02

We have reviewed all general outbreaks of infection due to Vero cytotoxin producing Escherichia coli (VTEC) O157 reported in England and Wales from 1992 to 1994. One hundred and seventy-three people were affected in 18 outbreaks, compared with 76 people in seven outbreaks in the preceding three years (1989 to 1991). Outbreaks occurred throughout England and Wales. Thirty-eight per cent of cases were admitted to hospital, 21% developed haemolytic uraemic syndrome, and 3% died. VTEC O157 infection causes particular concern because of its serious complications--haemorrhagic colitis and haemolytic uraemic syndrome, its capacity to spread from person to person as well as by food and water, and its reservoir in dairy and beef cattle.

Physico-chemical characterization of terbium-161-chloride (161TbCl3) radioisotope from irradiated natural gadolinium oxide target

International Nuclear Information System (INIS)

Azmairit Aziz; Nana Suherman

2015-01-01

Currently cancer patients are increasing every year in Indonesia and become the third leading cause of death after heart disease and high blood pressure. Terbium-161 ( 161 Tb) is a low β- emitter (E β - = 0.155 MeV, T 1/2 = 6.9 d) and very similar to 177 Lu in terms of half-life, E β - energy and chemical properties.However, 161 Tb also ejects internal conversion electrons and Auger electrons which can provide a greater therapeutic effect than 177 Lu. Radioisotope of 161 Tb can be produced as a carrier-free for use in labeling of biomolecules as a targeted radiopharmaceutical for cancer therapy. 161 Tb was obtained through 160 Gd(n,γ) 161 Tb nuclear reaction by thermal neutron bombardment on 100 mg of natural gadolinium oxide target in RSG-G.A. Siwabessy at a thermal neutron flux of ~10 14 n.cm -2 .s -1 and followed by radiochemical separation of 161 Tb from Gd isotopes using extraction chromatography method. The physico-chemical characterization of 161 TbCl 3 solution was studied by determination of its radionuclide purity by means of a γ-rays spectrometry with HP-Ge detector coupled to a multichannel analyzer (MCA). Radiochemical purity was determined using paper chromatography and paper electrophoresis methods. The results showed that 161 TbCl 3 radioisotope has a pH of 2, radiochemical purity of 99.64 ± 0.34%, radionuclide purity of 99.69 ± 0.20%, specific activity and radioactive concentration at the end of irradiation (EOI) of 2.26 – 5.31 Ci/mg and 3.84 – 9.03 mCi/mL, respectively. 161 TbCl 3 solution stable for 3 weeks at room temperature with a radiochemical purity of 98.41 ± 0.42%. 161 TbCl 3 solution from irradiated natural gadolinium oxide target has the physico-chemical characteristic that meets the requirements for use as a precursor in preparation of radiopharmaceuticals. (author)

Fate of Escherichia coli O157:H7 and Salmonella on whole strawberries and blueberries of two maturities under different storage conditions.

Science.gov (United States)

Nguyen, Thao P; Friedrich, Loretta M; Danyluk, Michelle D

2014-07-01

Strawberries and blueberries harvested at or near full-ripe maturity tend to be less firm and more susceptible to bruising during harvest and transport. The objective of this research was to determine the fate of Escherichia coli O157:H7 and Salmonella on bruised and intact surfaces of whole strawberries and blueberries at shipping (2°C) and retail display (15.5°C) temperatures. Strawberries and blueberries were either purchased from a supermarket or were harvested immediately prior to use; they were bruised using established protocols, were spot inoculated, and were incubated at 2 and 15.5°C. Strawberries, subjected to modified atmospheres, were further transferred to bags and were sealed in with an initial atmosphere of ca. 10% CO2 and 5% O2. Strawberries were sampled at 0, 2, 5, and 24 h and on days 3 and 7; blueberries were sampled on days 0, 1, 3, and 7. After stomaching, samples were enumerated on nonselective and selective media, and populations were recorded as log CFU per berry. At both storage temperatures, population declines for both E. coli O157:H7 and Salmonella were seen under all conditions for strawberries. At 2 ± 2°C, E. coli O157:H7 and Salmonella populations on blueberries declined over 7 days under all conditions. At 15.5 ± 2°C, E. coli O157:H7 populations declined; however, Salmonella populations initially declined but increased to populations near or above initial populations over 7 days on blueberries. No overall significant differences were observed between bruised and intact treatments or between the two maturity levels for strawberries and blueberries. Modified atmospheric conditions did not affect the behavior of E. coli O157:H7 and Salmonella on strawberries at both temperatures. This research indicates that E. coli O157:H7 and Salmonella do not grow on strawberries at shipping or retail display temperatures, even when they are harvested at a maturity prone to bruising; however, Salmonella growth may occur on bruised full ripe

Influence of age, sex and herd characteristics on the occurrence of verocytotoxin-producing Escherichia coli O157 in Danish dairy farms

DEFF Research Database (Denmark)

Nielsen, E.M.; Tegtmeier, Conny; Andersen, Hans Jørgen

2002-01-01

animals were sampled, and 3.6% of these excreted VTEC O157. These animals were located on 10 farms (17%). On average, 21% of the sampled animals in the positive herds excreted VTEC O157. Register data, including age, sex, breed, housing conditions and herd composition, were extracted from a database....... No influence of herd size or housing conditions was found. A strong effect of age was seen with 2-6-month-old calves as the high-risk age group (8.6% positive) in contrast to calves...

21 CFR 516.157 - Publication of the index and content of an index listing.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Publication of the index and content of an index... MINOR SPECIES Index of Legally Marketed Unapproved New Animal Drugs for Minor Species § 516.157 Publication of the index and content of an index listing. (a) FDA will make the list of indexed drugs...

Transfer of Escherichia coli O157:H7 from equipment surfaces to fresh-cut leafy greens during processing in a model pilot-plant production line with sanitizer-free water.

Science.gov (United States)

Buchholz, Annemarie L; Davidson, Gordon R; Marks, Bradley P; Todd, Ewen C D; Ryser, Elliot T

2012-11-01

Escherichia coli O157:H7 contamination of fresh-cut leafy greens has become a public health concern as a result of several large outbreaks. The goal of this study was to generate baseline data for E. coli O157:H7 transfer from product-inoculated equipment surfaces to uninoculated lettuce during pilot-scale processing without a sanitizer. Uninoculated cored heads of iceberg and romaine lettuce (22.7 kg) were processed using a commercial shredder, step conveyor, 3.3-m flume tank with sanitizer-free tap water, shaker table, and centrifugal dryer, followed by 22.7 kg of product that had been dip inoculated to contain ∼10(6), 10(4), or 10(2) CFU/g of a four-strain avirulent, green fluorescent protein-labeled, ampicillin-resistant E. coli O157:H7 cocktail. After draining the flume tank and refilling the holding tank with tap water, 90.8 kg of uninoculated product was similarly processed and collected in ∼5-kg aliquots. After processing, 42 equipment surface samples and 46 iceberg or 36 romaine lettuce samples (25 g each) from the collection baskets were quantitatively examined for E. coli O157:H7 by direct plating or membrane filtration using tryptic soy agar containing 0.6% yeast extract and 100 ppm of ampicillin. Initially, the greatest E. coli O157:H7 transfer was seen from inoculated lettuce to the shredder and conveyor belt, with all equipment surface populations decreasing 90 to 99% after processing 90.8 kg of uncontaminated product. After processing lettuce containing 10(6) or 10(4) E. coli O157:H7 CFU/g followed by uninoculated lettuce, E. coli O157:H7 was quantifiable throughout the entire 90.8 kg of product. At an inoculation level of 10(2) CFU/g, E. coli O157:H7 was consistently detected in the first 21.2 kg of previously uninoculated lettuce at 2 to 3 log CFU/100 g and transferred to 78 kg of product. These baseline E. coli O157:H7 transfer results will help determine the degree of sanitizer efficacy required to better ensure the safety of fresh-cut leafy

Efficacy of integrated treatment of UV light and low dose gamma irradiation on Escherichia coli O157:H7 and Salmonella enterica on grape tomatoes

Science.gov (United States)

Efficacy of integrated treatment of UVC and low dose Gamma irradiation to inactivate mixed Strains of Escherichia coli O157:H7 and Salmonella enterica inoculated on whole Grape tomatoes was evaluated. A mixed bacterial cocktail composed of a three strain mixture of E. coli O157:H7 (C9490, E02128 an...

Genome sequences of thirty Escherichia coli O157:H7 isolates recovered from a single dairy farm and its associated off-site heifer raising facility

Science.gov (United States)

Cattle are the primary reservoir of Escherichia coli O157:H7, the most frequently isolated serotype of enterohemorrhagic E. coli infections among humans in North America. To evaluate the diversity of E. coli O157:H7 isolates within a single dairy herd the genomes of 30 isolates collected over a 7-ye...

Rapid and Accurate Detection of Bacteriophage Activity against Escherichia coli O157:H7 by Propidium Monoazide Real-Time PCR

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Hui Liu

2014-01-01

Full Text Available Conventional methods to determine the efficacy of bacteriophage (phage for biocontrol of E. coli require several days, due to the need to culture bacteria. Furthermore, cell surface-attached phage particles may lyse bacterial cells during experiments, leading to an overestimation of phage activity. DNA-based real-time quantitative polymerase chain reaction (qPCR is a fast, sensitive, and highly specific means of enumerating pathogens. However, qPCR may underestimate phage activity due to its inability to distinguish viable from nonviable cells. In this study, we evaluated the suitability of propidium monoazide (PMA, a microbial membrane-impermeable dye that inhibits amplification of extracellular DNA and DNA within dead or membrane-compromised cells as a means of using qPCR to identify only intact E. coli cells that survive phage exposure. Escherichia coli O157:H7 strain R508N and 4 phages (T5-like, T1-like, T4-like, and O1-like were studied. Results compared PMA-qPCR and direct plating and confirmed that PMA could successfully inhibit amplification of DNA from compromised/damaged cells E. coli O157:H7. Compared to PMA-qPCR, direct plating overestimated (P < 0.01 phage efficacy as cell surface-attached phage particles lysed E. coli O157:H7 during the plating process. Treatment of samples with PMA in combination with qPCR can therefore be considered beneficial when assessing the efficacy of bacteriophage for biocontrol of E. coli O157:H7.

A Broad G Protein-Coupled Receptor Internalization Assay that Combines SNAP-Tag Labeling, Diffusion-Enhanced Resonance Energy Transfer, and a Highly Emissive Terbium Cryptate.

Science.gov (United States)

Levoye, Angélique; Zwier, Jurriaan M; Jaracz-Ros, Agnieszka; Klipfel, Laurence; Cottet, Martin; Maurel, Damien; Bdioui, Sara; Balabanian, Karl; Prézeau, Laurent; Trinquet, Eric; Durroux, Thierry; Bachelerie, Françoise

2015-01-01

Although G protein-coupled receptor (GPCR) internalization has long been considered as a major aspect of the desensitization process that tunes ligand responsiveness, internalization is also involved in receptor resensitization and signaling, as well as the ligand scavenging function of some atypical receptors. Internalization thus contributes to the diversity of GPCR-dependent signaling, and its dynamics and quantification in living cells has generated considerable interest. We developed a robust and sensitive assay to follow and quantify ligand-induced and constitutive-induced GPCR internalization but also receptor recycling in living cells. This assay is based on diffusion-enhanced resonance energy transfer (DERET) between cell surface GPCRs labeled with a luminescent terbium cryptate donor and a fluorescein acceptor present in the culture medium. GPCR internalization results in a quantifiable reduction of energy transfer. This method yields a high signal-to-noise ratio due to time-resolved measurements. For various GPCRs belonging to different classes, we demonstrated that constitutive and ligand-induced internalization could be monitored as a function of time and ligand concentration, thus allowing accurate quantitative determination of kinetics of receptor internalization but also half-maximal effective or inhibitory concentrations of compounds. In addition to its selectivity and sensitivity, we provided evidence that DERET-based internalization assay is particularly suitable for characterizing biased ligands. Furthermore, the determination of a Z'-factor value of 0.45 indicates the quality and suitability of DERET-based internalization assay for high-throughput screening (HTS) of compounds that may modulate GPCRs internalization.

Identification of E. coli O157:H7 by Using Specific Primers for rfbE and stx2b Genes

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Mostafa Bakhshi

2017-07-01

Sorbitol-MacConkey agar was used to verification of growth ability of selected colonies during PCR. Results: By appearance of the bonds belong to rfbE and stx2B genes on agarose gel, the ability of designed primers in gene detection in samples of E .coli O157:H7 was verified. Colonies which selected during PCR have growth potency on sorbitol-MacConkey agar medium. Conclusion: It was revealed that we can prepare a fast, precise and relative comfortable method for detection of E. coli O157:H7 strain by using PCR technique and specific primers than other available methods.

Therapeutic use of radioactive isotopes

CERN Document Server

Caroline Duc

2013-01-01

In December, researchers from ISOLDE-CERN, the Paul Scherrer Institute (PSI) and the Institut Laue-Langevin (ILL) published the results of an in vivo study which successfully proved the effectiveness of four terbium isotopes for diagnosing and treating cancerous tumours.   Four terbium isotopes suitable for clinical purposes. “ISOLDE is the only installation capable of supplying terbium isotopes of such purity and intensity in the case of three out of the four types used in this study,” explains Karl Johnson, a physicist at ISOLDE.  “Producing over a thousand different isotopes, our equipment offers the widest choice of isotopes in the world!” Initially intended for fundamental physics research, ISOLDE has diversified its activities over time to invest in various projects in the materials science, biochemistry and nuclear medicine fields. The proof-of-concept study has confirmed that the four terbium isotopes 149Tb, 152Tb, 155Tb produ...

18 CFR Appendix I to Subpart F of... - Procedures for Compliance With the Endangered Species Act of 1973 Under § 157.206(b)(3)(i)

Science.gov (United States)

2010-04-01

... Compliance With the Endangered Species Act of 1973 Under § 157.206(b)(3)(i) I Appendix I to Subpart F of... Compliance With the Endangered Species Act of 1973 Under § 157.206(b)(3)(i) The following procedures apply to... ENERGY REGULATIONS UNDER NATURAL GAS ACT APPLICATIONS FOR CERTIFICATES OF PUBLIC CONVENIENCE AND...

Cloning and characterization of GDP-perosamine synthetase (Per) from Escherichia coli O157:H7 and synthesis of GDP-perosamine in vitro

International Nuclear Information System (INIS)

Zhao Guohui; Liu Jun; Liu Xiang; Chen Min; Zhang Houcheng; Wang, Peng George

2007-01-01

GDP-perosamine synthetase (Per, E.C. not yet classified) is important to the synthesis of Escherichia coli O157:H7 O-antigen. The mutant in per gene can disrupt the synthesis of O157 O-antigen. In this study, GDP-perosamine synthetase was cloned from E. coli O157:H7 and over-expressed in E. coli BL21 (DE3). The recombinant His-tagged Per fusion protein was a decamer with molecular weight of 431 kDa. The optimal pH value of this recombinant protein was 7.5. The divalent ions had no significant effect on Per-catalyzed reaction. The K m and K cat /K m for GDP-4-keto-6-deoxy-D-mannose were 0.09 mM and 2.1 x 10 5 M -1 S -1 , and those for L-glutamate were 2 mM and 0.52 x 10 5 M -1 S -1 , respectively. Per was used to synthesize GDP-perosamine from GDP-mannose together with recombinant GDP-mannose dehydratase (GMD, E.C. 4.2.1.47). The purified GDP-perosamine was identified by MS and NMR. In summary, this work provided a feasible approach for the synthesis of GDP-perosamine which can lead to the study of LPS biosynthesis of pathogenic E. coli O157:H7

Surveillance of Virulence Markers and Antibiotic Resistance of Shiga toxin Producing E.coli O157:H7 Strains from Meats Purchase in Shiraz

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Mohammad Kargar

2011-09-01

Full Text Available Background: Shiga toxin Producing Escherichia coli O157:H7 is a common pathogen in cattle, which occasional causes some human disease. This bacterium can potentially contaminate meat and clinical cases of E.coli O157:H7 infections are often associated with consumption of undercooked ground beef. Methods: In this cross-sectional study 122 samples of ground meat were collected and after enrichment in specific culture media and evaluation sorbitol fermentation and their β-glucoronidase activity, the isolation of E.coli O157:H7 strains have been confirmed with specific antisera. Then virulence genes verotoxin, intimin and hemolysin with multiplex PCR and antibiotic resistance strains with disk diffusion method have been tested. Results: Out of specimens that have been supplied, 119 sorbitol negative colonies isolated which 3 strains O157:H7 (2.45% with specific antisera confirmed. Out of considered virulence genes, in two cases of these samples (1.64% the stx1 and eaeA genes were seen and also 2 isolated bacteria had resistance to erythromycin, tetracycline, ampicillin, penicillin, clindamicin, cefixime, novobiocin, and gentamicin antibiotics. Conclusion: As this organism lives in intestines of healthy cattle, preventive measures on cattle farms and during meat processing are necessary.

Survey of Shiga toxin-producing Escherichia coli O157:H7 in urban pigeons (Columba livia in the city of Napoli, Italy

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Alessandro Fioretti

2010-01-01

Full Text Available Recently, several studies have demonstrated that pigeon is an important reservoir of Shiga toxin-producing E. coli O157:H7. The aim of this study was to evaluate the presence of this pathogen in urban pigeons in the city of Napoli. The sampling was carried out during the period November 2005/July 2006. The city was subdivided in 56 quadrants by Geographical Information System. Each quadrant was analysed three times. From each quadrant, 3 pigeons were analysed by cloacal swabs. A total of 504 cloacal swabs was obtained. We isolated four E. coli O157:H7 strains. By multiplex PCR, all strains carried eae and stx2 genes, whereas only one strain carried the stx1 gene. 2/4 isolated strains carried hly gene which is considered a hallmark of human pathogenic strains. Our results indicate that pigeon faces are a source of E. coli O157:H7 for birds, mammals and humans.

Carvacrol Induces Heat Shock Protein 60 and Inhibits Synthesis of Flagellin in Escherichia coli O157:H7▿

Science.gov (United States)

Burt, Sara A.; van der Zee, Ruurd; Koets, Ad P.; de Graaff, Anko M.; van Knapen, Frans; Gaastra, Wim; Haagsman, Henk P.; Veldhuizen, Edwin J. A.

2007-01-01

The essential oils of oregano and thyme are active against a number of food-borne pathogens, such as Escherichia coli O157:H7. Carvacrol is one of the major antibacterial components of these oils, and p-cymene is thought to be its precursor in the plant. The effects of carvacrol and p-cymene on protein synthesis in E. coli O157:H7 ATCC 43895 cells were investigated. Bacteria were grown overnight in Mueller-Hinton broth with a sublethal concentration of carvacrol or p-cymene, and their protein compositions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and confirmed by Western blotting. The presence of 1 mM carvacrol during overnight incubation caused E. coli O157:H7 to produce significant amounts of heat shock protein 60 (HSP60) (GroEL) (P < 0.05) and inhibited the synthesis of flagellin highly significantly (P < 0.001), causing cells to be aflagellate and therefore nonmotile. The amounts of HSP70 (DnaK) were not significantly affected. p-Cymene at 1 mM or 10 mM did not induce HSP60 or HSP70 in significant amounts and did not have a significant effect on flagellar synthesis. Neither carvacrol (0.3, 0.5, 0.8, or 1 mM) nor p-cymene (0.3, 0.5, or 0.8 mM) treatment of cells in the mid-exponential growth phase induced significant amounts of HSP60 or HSP70 within 3 h, although numerical increases of HSP60 were observed. Motility decreased with increasing concentrations of both compounds, but existing flagella were not shed. This study is the first to demonstrate that essential oil components induce HSP60 in bacteria and that overnight incubation with carvacrol prevents the development of flagella in E. coli O157:H7. PMID:17526792

Evaluation of the New DIN Standard for Quality Assurance of Diagnostic Displays - Technical Review DIN 6868-157.

Science.gov (United States)

Entz, Kathrin; Sommer, Alexander; Lenzen, Horst

2018-01-01

Acceptance and regular constancy tests are necessary to ensure the quality of diagnostic displays. In November 2014, a new standard (DIN 6868-157) was published which defines the test procedure and limiting values. There are several substantial changes compared with the previous standard DIN V 6868-57, i. e. considering the complete image display system including workstation and application software instead of only the displays. Since its publication, the new standard has raised many questions. This technical review aims to show the strengths and weaknesses of the new standard. Positive aspects are the introduction of a limiting value for the illuminance and the extension of the interval for constancy tests from 3 to 6 six months. The daily constancy test on the other hand, raises several problems and should be replaced by a randomized test. Additionally, the medical relevance is critically questioned and an overview of software for the quality assurance will be given.   · Acceptance and constancy tests for diagnostic displays are defined in DIN 6868-157.. · The new standards has positive and negative aspects.. · Randomized tests should be introduced.. · Entz K, Sommer A, Lenzen H. DIN 6868-157: Image Quality Assurance in Diagnostic X-ray Departments - X-ray Ordinance Acceptance and Constancy Test of Image Display Systems in their Environment - Technical Review -. Fortschr Röntgenstr 2018; 190: 51 - 60. © Georg Thieme Verlag KG Stuttgart · New York.

Problems in classical electromagnetism 157 exercises with solutions

CERN Document Server

Macchi, Andrea; Pegoraro, Francesco

2017-01-01

This book contains 157 problems in classical electromagnetism, most of them new and original compared to those found in other textbooks. Each problem is presented with a title in order to highlight its inspiration in different areas of physics or technology, so that the book is also a survey of historical discoveries and applications of classical electromagnetism. The solutions are complete and include detailed discussions, which take into account typical questions and mistakes by the students. Without unnecessary mathematical complexity, the problems and related discussions introduce the student to advanced concepts such as unipolar and homopolar motors, magnetic monopoles, radiation pressure, angular momentum of light, bulk and surface plasmons, radiation friction, as well as to tricky concepts and ostensible ambiguities or paradoxes related to the classical theory of the electromagnetic field. With this approach the book is both a teaching tool for undergraduates in physics, mathematics and electric engine...

Effect of proximity to a cattle feedlot on Escherichia coli O157:H7 contamination of leafy greens and evaluation of the potential for airborne transmission.

Science.gov (United States)

Berry, Elaine D; Wells, James E; Bono, James L; Woodbury, Bryan L; Kalchayanand, Norasak; Norman, Keri N; Suslow, Trevor V; López-Velasco, Gabriela; Millner, Patricia D

2015-02-01

The impact of proximity to a beef cattle feedlot on Escherichia coli O157:H7 contamination of leafy greens was examined. In each of 2 years, leafy greens were planted in nine plots located 60, 120, and 180 m from a cattle feedlot (3 plots at each distance). Leafy greens (270) and feedlot manure samples (100) were collected six different times from June to September in each year. Both E. coli O157:H7 and total E. coli bacteria were recovered from leafy greens at all plot distances. E. coli O157:H7 was recovered from 3.5% of leafy green samples per plot at 60 m, which was higher (P green field distance guidelines of 120 m (400 feet) may not be adequate to limit the transmission of E. coli O157:H7 to produce crops planted near concentrated animal feeding operations. Additional research is needed to determine safe set-back distances between cattle feedlots and crop production that will reduce fresh produce contamination. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Transfer, attachment, and formation of biofilms by Escherichia coli O157:H7 on meat-contact surface materials.

Science.gov (United States)

Simpson Beauchamp, Catherine; Dourou, Dimitra; Geornaras, Ifigenia; Yoon, Yohan; Scanga, John A; Belk, Keith E; Smith, Gary C; Nychas, George-John E; Sofos, John N

2012-06-01

Studies examined the effects of meat-contact material types, inoculation substrate, presence of air at the liquid-solid surface interface during incubation, and incubation substrate on the attachment/transfer and subsequent biofilm formation by Escherichia coli O157:H7 on beef carcass fabrication surface materials. Materials studied as 2 × 5 cm coupons included stainless steel, acetal, polypropylene, and high-density polyethylene. A 6-strain rifampicin-resistant E. coli O157:H7 composite was used to inoculate (6 log CFU/mL, g, or cm²) tryptic soy broth (TSB), beef fat/lean tissue homogenate (FLH), conveyor belt-runoff fluids, ground beef, or beef fat. Coupons of each material were submerged (4 °C, 30 min) in the inoculated fluids or ground beef, or placed between 2 pieces of inoculated beef fat with pressure (20 kg) applied. Attachment/transfer of the pathogen was surface material and substrate dependent, although beef fat appeared to negate differences among surface materials. Beef fat was the most effective (P transfer and subsequent biofilm formation by E. coli O157:H7. The results highlight the importance of thoroughly cleaning soiled surfaces to remove all remnants of beef fat or other organic material that may harbor or protect microbial contaminants during otherwise lethal antimicrobial interventions. © 2012 Institute of Food Technologists®

Inactivation of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhimurium with compounds available in households.

Science.gov (United States)

Yang, Hua; Kendall, Patricia A; Medeiros, Lydia; Sofos, John N

2009-06-01

Solutions of selected household products were tested for their effectiveness against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium. Hydrogen peroxide (1.5 and 3%), vinegar (2.5 and 5% acetic acid), baking soda (11, 33, and 50% sodium bicarbonate), household bleach (0.0314, 0.0933, and 0.670% sodium hypochlorite), 5% acetic acid (prepared from glacial acetic acid), and 5% citric acid solutions were tested against the three pathogens individually (five-strain composites of each, 10(8) CFU/ml) by using a modified AOAC International suspension test at initial temperatures of 25 and 55degrees C for 1 and 10 min. All bleach solutions (pH 8.36 to 10.14) produced a >5-log reduction of all pathogens tested after 1 min at 25 degrees C, whereas all baking soda solutions (pH 7.32 to 7.55) were ineffective (5-log reduction of both Salmonella Typhimurium and E. coli O157:H7, whereas undiluted vinegar (pH 2.58) had a similar effect only against Salmonella Typhimurium. Compared with 1 min at 25 degrees C, greater reductions of L. monocytogenes (P 3% hydrogen peroxide > undiluted vinegar and 5% acetic acid > 5% citric acid > baking soda (50% sodium bicarbonate). The sensitivity of the tested pathogens to all tested household compounds followed the sequence of Salmonella Typhimurium > E. coli O157: H7 > L. monocytogenes.

Determining Thermal Inactivation of Escherichia coli O157:H7 in Fresh Compost by Simulating Early Phases of the Composting Process ▿

OpenAIRE

Singh, Randhir; Kim, Jinkyung; Shepherd, Marion W.; Luo, Feng; Jiang, Xiuping

2011-01-01

A three-strain mixture of Escherichia coli O157:H7 was inoculated into fresh dairy compost (ca. 107 CFU/g) with 40 or 50% moisture and was placed in an environmental chamber (ca. 70% humidity) that was programmed to ramp from room temperature to selected composting temperatures in 2 and 5 days to simulate the early composting phase. The surviving E. coli O157:H7 population was analyzed by direct plating and enrichment. Optimal and suboptimal compost mixes, with carbon/nitrogen (C/N) ratios of...

Changing plasmid types responsible for extended spectrum cephalosporin resistance in Escherichia coli O157:H7 in the United States, 1996–2009

OpenAIRE

Folster, J. P.; Pecic, G.; Stroika, S.; Rickert, R.; Whichard, J.

2014-01-01

Escherichia coli O157 is a major cause of foodborne illness. Plasmids are genetic elements that mobilize antimicrobial resistance determinants including blaCMY β-lactamases that confer resistance to extended-spectrum cephalosporins (ESC). ESCs are important for treating a variety of infections. IncA/C plasmids are found among diverse sources, including cattle, the principal source of E. coli O157 infections in humans. IncI1 plasmids are common among E. coli and Salmonella from poultry and oth...

Armazenamento refrigerado sob atmosfera modificada de pedúnculos de cajueiro-anão-precoce dos clones CCP-76, end-157, end-183 e end-189 Storage of cashew apples from dwarf clones CCP-76, end-157, end-183 and end-189 under refrigeration and modified atmosphere

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Auricélia de Souza Morais

2002-12-01

Full Text Available Pedúnculos de clones de cajueiro-anão-precoce, dos clones CCP-76, END-157, END-183 e END-189, foram armazenados durante 25 dias, sob refrigeração associada a atmosfera modificada, com o objetivo de avaliar o efeito das condições atualmente utilizadas (5ºC e 85-90% de UR para conservação, transporte e comercialização de cajus in natura. Os pedúnculos foram avaliados a cada 5 dias quanto às seguintes características: perda de peso, firmeza, cor (antocianinas, sólidos e açúcares solúveis, acidez, pH, vitamina C e compostos fenólicos. O uso da refrigeração (5ºC e 85% U.R, associada a atmosfera modificada, proporcionou uma vida útil pós-colheita de 10 dias para o clone END 189, de até 15 dias para o clone END 157 e de até 25 dias para os clones CCP 76 e END 183. A temperatura de 5ºC não se mostrou adequada para armazenamento de pedúnculos de coloração mais intensa (END 157 e END 189 que a testemunha (CCP 76, provocando perda de cor (antocianinas a partir do 10º dia de armazenamento. A atmosfera modificada reduziu significativamente a perda de peso, favorecendo a aparência do produto para comercialização, independentemente do clone estudado.Apples or false fruits from early dwarf cashew clones CCP-76, END-157, END-183 and END-189 were stored for 25 days under refrigeration associated to modified atmosphere with the aim of evaluating the effect of the conditions presently adopted (5ºC and 85-90% RH for conservation, storage and commercialization of fresh cashew apples. The cashew apples were evaluated every 5 days for the following characteristics: weight loss, pulp firmness, color (anthocyannins, acidity, pH, soluble solids, vitamin C and phenolic contents. With the use of refrigeration and modified atmosphere it was possible to attain postharvest storage life of 10 days for clone END 189, 15 days for clone END 157 and up to 25 days for clones CCP 76 and END 183. It was found that 5ºC was not an adequate

14 CFR 382.157 - What are carriers' obligations for recordkeeping and reporting on disability-related complaints?

Science.gov (United States)

2010-01-01

... the type of disability and nature of complaint. Data concerning a passenger's disability must be... NONDISCRIMINATION ON THE BASIS OF DISABILITY IN AIR TRAVEL Complaints and Enforcement Procedures § 382.157 What are... purposes of this section, a disability-related complaint means a specific written expression of...

Frequency and risk-factors analysis of Escherichia coli O157:H7 in Bali-cattle.

Science.gov (United States)

Suardana, I Wayan; Widiasih, Dyah Ayu; Nugroho, Widagdo Sri; Wibowo, Michael Haryadi; Suyasa, I Nyoman

2017-08-01

Cattle are known as the main reservoir of zoonotic agents verocytotoxin-producing Escherichia coli. These bacteria are usually isolated from calves with diarrhea and/or mucus and blood. Tolerance of these agents to the environmental conditions will strengthen of their transmission among livestock. A total of 238 cattle fecal samples from four sub-districts in Badung, Bali were used in this study. Epidemiological data observed include cattle age, sex, cattle rearing system, the source of drinking water, weather, altitude, and type of cage floor, the cleanliness of cage floor, the slope of cage floor, and the level of cattle cleanliness. The study was initiated by culturing of samples onto eosin methylene blue agar, then Gram stained, and tested for indole, methyl-red, voges proskauer, and citrate, Potential E.coli isolates were then cultured onto sorbitol MacConkey agar, and further tested using O157 latex agglutination test and H7 antisera. Molecular identification was performed by analysis of the 16S rRNA gene, and epidemiological data was analyzed using STATA 12.0 software. The results showed, the prevalence of E. coli O157:H7 in cattle at Badung regency was 6.30% (15/238) covering four sub districts i.e. Petang, Abiansemal, Mengwi, and Kuta which their prevalence was 8.62%(5/58), 10%(6/60), 3.33%(2/60), and 3.33(2/60)%, respectively. The analysis of 16S rRNA gene confirmed of isolates as an E. coli O157:H7 strain with 99% similarities. Furthermore, the risk factors analysis showed that the slope of the cage floor has a highly significant effect (P<0.05) to the distribution of infection. Consequently, implementing this factor must be concerned in order to decrease of infection. Copyright © 2017 Elsevier B.V. All rights reserved.

Incidence and antimicrobial susceptibility of Escherichia coli O157:H7 isolates recovered from dairy farms in Amathole District Municipality, Eastern Cape, South Africa

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Asive Myataza

2017-11-01

Full Text Available Objective: To assess the incidence of Escherichia coli (E. coli O157:H7 in water and cattle rectal samples from three commercial dairy farms in Amathole District Municipalities in the Eastern Cape Province of South Africa. Methods: Samples were collected bimonthly from cattle rectum and dairy water sources including irrigation water, drinking water troughs and wastewater between June and November 2014. Standard culture-based methods were applied for the microbial analyses, the disc diffusion method was employed for the antibiotic susceptibility test and PCR approach was utilized for identification of the isolates. Results: A total of 252 presumptive E. coli O157:H7 were isolated and subjected to molecular confirmation by PCR. About 18.7% (47/252 of these were confirmed as E. coli O157:H7. The antimicrobial susceptibility profile of these confirmed isolates revealed high-level resistance against penicillin G (81%, tetracycline (43%, oxytetracycline (62%, erythromycin (68%, sulphamethoxazole (57%, chloramphenicol (55%, doxycycline (51% and trimethoprimsulphamethoxazole (45%. Conclusions: This is the first report of multi-drug resistance E. coli O157:H7 in commercial dairy farms in the province and suggests the possibility of same in other provinces of the country, and this is the subject of the intensive investigation in our group.

Ziziphora clinopodioides Essential Oil and Nisin as Potential Antimicrobial Agents against Escherichia coli O157:H7 in Doogh (Iranian Yoghurt Drink

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Yasser Shahbazi

2015-01-01

Full Text Available The aim of the present study was to evaluate the effects of Ziziphora clinopodioides essential oil (0.1 and 0.2% and nisin (250 and 500 IU/mL separately and in combination on survival of Escherichia coli O157:H7 inoculated in Doogh (Iranian yoghurt drink during storage under refrigerated temperature (4 ± 1°C for 9 days. Viability of Lactobacillus casei at different concentrations of Z. clinopodioides essential oil (0.1 and 0.2% in Doogh was also examined. The major components were carvacrol (64.22%, thymol (19.22%, γ-terpinene (4.63%, and p-cymene (4.86%. There was no significant difference (p>0.05 between samples treated with nisin and those of untreated samples. Samples treated with both concentrations of the essential oil (0.1 and 0.2% showed populations of E. coli O157:H7 significantly (p<0.05 lower than those of untreated samples. The essential oil of Z. clinopodioides in combination with nisin had a potential synergistic effect against E. coli O157:H7 in Doogh samples after 5 days. The count of L. casei was not inhibited by different concentrations of the Z. clinopodioides essential oil. It is concluded that the leaf essential oil of Z. clinopodioides in combination with nisin can be applied as alternative antimicrobial agents in Doogh to inhibit the growth of E. coli O157:H7.

Fate of Escherichia coli O157:H7 and Salmonella in soil and lettuce roots as affected by potential home gardening practices.

Science.gov (United States)

Erickson, Marilyn C; Liao, Jean; Payton, Alison S; Webb, Cathy C; Ma, Li; Zhang, Guodong; Flitcroft, Ian; Doyle, Michael P; Beuchat, Larry R

2013-12-01

The survival and distribution of enteric pathogens in soil and lettuce systems were investigated in response to several practices (soil amendment supplementation and reduced watering) that could be applied by home gardeners. Leaf lettuce was grown in manure compost/top soil (0:5, 1:5 or 2:5 w/w) mixtures. Escherichia coli O157:H7 or Salmonella was applied at a low or high dose (10(3) or 10(6) colony-forming units (CFU) mL(-1) ) to the soil of seedlings and mid-age plants. Supplementation of top soil with compost did not affect pathogen survival in the soil or on root surfaces, suggesting that nutrients were not a limiting factor. Salmonella populations on root surfaces were 0.7-0.8 log CFU g(-1) lower for mid-age plants compared with seedlings. E. coli O157:H7 populations on root surfaces were 0.8 log CFU g(-1) lower for mid-age plants receiving 40 mL of water compared with plants receiving 75 mL of water on alternate days. Preharvest internalization of E. coli O157:H7 and Salmonella into lettuce roots was not observed at any time. Based on the environmental conditions and high pathogen populations in soil used in this study, internalization of Salmonella or E. coli O157:H7 into lettuce roots did not occur under practices that could be encountered by inexperienced home gardeners. © 2013 Society of Chemical Industry.

Simultaneous Detection of Escherichia coli O157:H7, Salmonella enteritidis, and Listeria monocytogenes at a Very Low Level Using Simultaneous Enrichment Broth and Multichannel SPR Biosensor.

Science.gov (United States)

Zhang, Xiaoguang; Tsuji, Sachiko; Kitaoka, Hayato; Kobayashi, Hiroshi; Tamai, Mitsuru; Honjoh, Ken-Ichi; Miyamoto, Takahisa

2017-10-01

Detection of foodborne pathogens at very low levels is still a challenge. A custom-built multichannel surface plasmon resonance (SPR) biosensor and simultaneous enrichment broth (SEB) were used to develop a simultaneous detection method for 3 important foodborne pathogens, Escherichia coli O157:H7 (O157:H7), Salmonella enteritidis, and Listeria monocytogenes, at a very low level. These 3 foodborne pathogens at a very low level (14, 6, and 28 CFU/25 g (mL) for O157:H7, S. enteritidis, and L. monocytogenes, respectively) were inoculated in SEB and incubated at 37 ˚C for 24 h. Sample prepared from the simultaneous enrichment culture was analyzed using the multichannel SPR biosensor and sensor chip immobilized with polyclonal antibodies specific to each of the target pathogens. O157:H7, S. enteritidis, and L. monocytogenes in chicken were detected simultaneously at an inoculum dose of 14, 6, and 28 CFU/25 g, respectively. Our method using a custom-built multichannel SPR biosensor and enrichment in SEB is expected as a rapid and simultaneous detection method for low levels of O157:H7, S. enteritidis, and L. monocytogenes in food. Our method is expected as a rapid and simultaneous detection method for pathogens at very low levels. It has great potential for safety control of food and microbiological detection applications. © 2017 Institute of Food Technologists®.

A broad G protein-coupled receptor internalization assay that combines SNAP-tag labeling, diffusion-enhanced resonance energy transfer, and a highly emissive terbium cryptate acceptor

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Angélique eLEVOYE

2015-11-01

Full Text Available Although G protein-coupled receptor (GPCR internalization has long been considered a major aspect of the desensitization process that tunes ligand responsiveness, internalization is also involved in receptor resensitization and signaling, as well as the ligand scavenging function of some atypical receptors. Internalization thus contributes to the diversity of GPCR-dependent signaling, and its dynamics and quantification in living cells has generated considerable interest. We developed a robust and sensitive assay to follow and quantify ligand-induced and constitutive GPCR internalization but also receptor recycling in living cells. This assay is based on diffusion-enhanced resonance energy transfer (DERET between cell surface GPCRs labeled with a luminescent terbium cryptate donor and a fluorescein acceptor present in the culture medium. GPCR internalization results in a quantifiable reduction of energy transfer. This method yields a high signal-to-noise ratio due to time-resolved measurements. For various GPCRs belonging to different classes, we demonstrated that constitutive and ligand-induced internalization could be monitored as a function of time and ligand concentration, thus allowing accurate quantitative determination of kinetics of receptor internalization but also half-maximal effective or inhibitory concentrations of compounds. In addition to its selectivity and sensitivity, we provided evidence that DERET-based internalization assay is particularly suitable for characterizing biased ligands. Furthermore, the determination of a Z’-factor value of 0.45 indicates the quality and suitability of DERET-based internalization assay for high-throughput screening (HTS of compounds that may modulate GPCRs internalization.

Effectiveness of Sanitizer D7(TM) against Escherichia coli O157:H7 and Salmonella biofilms

Science.gov (United States)

Introduction: Biofilm formation by E. coli O157:H7 and Salmonella enterica at meat processing plants poses a serious risk of meat product contamination. Available studies have shown that many common sanitizers were unable to completely eradicate biofilms by these foodborne pathogens due to the 3-dim...

Whole-genome sequence of Escherichia coli serotype O157:H7 strain B6914-ARS

Science.gov (United States)

Escherichia coli serotype O157:H7 strain B6914-MS1 is a Shiga toxin-deficient human fecal isolate obtained by the Centers for Disease Control and Prevention that has been used extensively in applied research studies. Here we report the genome sequence of strain B6914-ARS, a B6914-MS1 clone that has ...

An ICP AES method for determination of dysprosium and terbium in high purity yttrium oxide

International Nuclear Information System (INIS)

Rupawate, V.H.; Hareendran, K.N.; Roy, S.B.

2011-01-01

High purity yttrium finds interesting application in astronavigation, luminescence, nuclear energy and metallurgical industries. Most of these applications require yttrium oxide of highest purity. Consequently there is a need for production of high purity yttrium oxide. Separation and purification of yttrium from other rare earths is a challenging task due to their close chemical properties. Liquid-liquid extraction and ion exchange have been widely used in the production of yttrium oxide of highest purity. Determination of impurities, especially other rare earths, in ppm level is required for process development and chemical characterization of the high purity Y 2 O 3 . Many methods have been described in literature. However since the advent of ICP AES much work in this area has been carried out by this technique. This paper describes the work done for determination of dysprosium (Dy) and terbium (Tb) in yttrium oxide using a high resolution sequential ICP AES. Emission spectra of rare earth elements are very complex and due to this complexity it is important to select spectral interference free analyte lines for determination of rare earths in rare earth matrix. For the determination of Dy and Tb in Y 2 O 3 , sensitive lines of Dy and Tb are selected from the instrument wavelength table and spectral interference free emission lines for the determination is selected by scanning around the selected wavelengths using 5 g/L Y solution and 5 mg/L standard solutions of Dy and Tb prepared in 4% nitric acid. It is found 353.170 nm line of Dy and 350.917 nm line Tb is suitable for quantitative determination. The signal to background ratio increases with increase in matrix concentration, i.e. from 1 to 5 mg/L. The optimum forward power is determined and it is found to be 1100W for Dy and 1000W for Tb. The instrument is calibrated using matrix matched standards containing 5g/L of Y matrix. Samples are dissolved in nitric acid and Y concentration is maintained at 5g/L. Two

Escherichia coli O157:H7 outbreak associated with consumption of ground beef, June-July 2002.

Science.gov (United States)

Vogt, Richard L; Dippold, Laura

2005-01-01

A case-control and environmental study tested the hypothesis that purchasing and eating ground beef from a specific source was the cause of a cluster of cases of hemolytic uremic syndrome (HUS) and Escherichia coli (E. coli) O157:H7 gastroenteritis. A case-control study comparing risk factors was conducted over the telephone on nine case-patients with 23 selected controls. An environmental investigation was conducted that consisted of reviewing beef handling practices at a specific local supermarket and obtaining ground beef samples from the store and two households with case-patients. The analysis of the case-control study showed that eight case-patients (89%) purchased ground beef at Grocery Chain A compared with four controls who did not develop illness (17%) (matched odds ratio=undefined; 95% confidence interval 2.8, infinity; p=0.006). The environmental investigation showed that Grocery Chain A received meat from Meatpacker A. Laboratory analysis of meat samples from Meatpacker A and Grocery Chain A and stool samples from some patients recovered an identical strain of E. coli O157:H7 according to pulse-field gel electrophoresis. Both the case-control and environmental studies showed that purchasing ground beef at Grocery Chain A, which received ground beef from Meatpacker A, was the major risk factor for illness in eight case-patients; the ninth case-patient was found to be unrelated to the outbreak. Furthermore, meat from Meatpacker A was associated with a nationwide outbreak of E. coli O157:H7 illness that resulted in the second largest recall of beef in U.S. history at the time.

THE (UN? FAIRNESS OF FAIR VALUE: SFAS 157, IRVING FISHER AND GECON

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Paulo Roberto Barbosa Lustosa

2017-01-01

Full Text Available Objective: The objective of this study is to assess the level of adherence of explicit and implicit measurement concepts present in SFAS 157 – Fair Value Measurements to traditional economic-accounting concepts. Background: The expansion of situations in which fair value measurement is required makes more difficult to ensure that the computed measure of value is actually fair. Out of the objectivity of current sales prices in an active market, all other measures of value are expectations about the future, inherently uncertain and inaccurate. Thus, the desired justice of the computed figures lies not in its accuracy, but in the using of the correct concepts for measuring accounting transactions and events. Method: To reach the objective, the characteristics of this standard are confronted with the secular concept of capital and income set by the laureate American neoclassical economist Irving Fisher, which were incorporated into Information System for Economic Management (Gecon. Results: The results indicate that SFAS 157 fair value concept and measurement structure are incorrect or incomplete, suggesting that the maintenance of the fair value expression in accounting seems inadequate. Contributions: This paper contributes to the literature on accounting measurement showing that as a measurement concept in accounting fair value seems inadequate. In abnormal situations or absence of a market, the measure found is always inexact and subjective, and therefore is not correct to call fair the quantity resulting from this arbitrary calculation.

Prevalence, quantification and isolation of pathogenic shiga toxin Escherichia coli O157:H7 along the production and supply chain of pork around Hubei Province of China.

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Khan, Sher Bahadar; Zou, Geng; Xiao, Ran; Cheng, Yuting; Rehman, Zia Ur; Ali, Sher; Memon, Atta Muhammad; Fahad, Shah; Ahmad, Irshad; Zhou, Rui

2018-02-01

Shiga toxin Escherichia coli (STEC) O157:H7 is an important zoonotic food borne pathogen causing gastroenteritis that may lead to life threatening hemorragic colitis (HC) and hemorrhagic uremic syndrome (HUS). 325 meat and tissue samples were tested for enumeration of O157:H7 strains using most probable number (MPN)-PCR targeting their specific genes flicH7 and rfbO157 followed by isolation, sereotyping and pathogenicity testing. The overall prevalence of O157:H7 was 41.3% (134/325) along the production and supply chain of pork (PSCP), being higher in supply chain (59%, 118/200) as compared to pig farms (12.8%, 16/125). Along the PSCP, the highest prevalence was found in slaughter houses (86.25%, 69/80) followed by wet- (53.3%, 32/60) and super-markets (28.3%, 17/60). The MPN values ranged from 3 to 1100 MPN/g in overall positive samples, being higher in slaughter houses followed by wet and super markets. Except from intestine and meat samples of slaughter house, the MPN was found higher in summer as compared to winter samples. Eight STEC O157:H7 isolated from meat and liver samples were tested in Balb/C mice for pathogenicity. After development of clinical signs and symptoms, 50-83.3% mortality was produced in the infected mice. Histopathological investigations revealed visible necrosis of intestinal epithelial cells, shedding of cellular debris in the intestine, while in the kidney, necrosis of renal cortical portion of tubular epithelial cells was observed. STEC O157:H7 is prevalent along PSCP around Hubei of China in different proportions being alarmingly higher in supply chain and markets which is a matter of concern for public health. Copyright © 2017. Published by Elsevier Ltd.

Strategies to Reduce Person-to-Person Transmission During Widespread Escherichia coli O157:H7 Outbreak

Centers for Disease Control (CDC) Podcasts

US consumers were warned not to eat raw spinach during a 2006 E. coli O157:H7 outbreak, but additional warnings about person-to-person transmission could have reduced bacteria spread. Dr. Martin Meltzer discusses the research methods and findings and the authors' success in presenting them clearly and accurately.

Physical Covering for Control of Escherichia coli O157:H7 and Salmonella spp. in Static and Windrow Composting Processes

Science.gov (United States)

Yossa, Irene; Macarisin, Dumitru; Millner, Patricia

2015-01-01

This study investigated the effect of a 30-cm covering of finished compost (FC) on survival of Escherichia coli O157:H7 and Salmonella spp. in active static and windrow composting systems. Feedstocks inoculated with E. coli O157:H7 (7.41 log CFU/g) and Salmonella (6.46 log CFU/g) were placed in biosentry tubes (7.5-cm diameter, 30-cm height) at three locations: (i and ii) two opposing sides at the interface between the FC cover layer (where present) and the feedstock material (each positioned approximately 10 cm below the pile's surface) and (iii) an internal location (top) (approximately 30 cm below the surface). On specific sampling days, surviving populations of inoculated E. coli O157:H7 and Salmonella, generic E. coli, and coliforms in compost samples were determined. Salmonella spp. were reduced significantly within 24 h in windrow piles and were below the detection limit after 3 and 7 days at internal locations of windrow and static piles containing FC covering, respectively. Likewise, E. coli O157:H7 was undetectable after 1 day in windrow piles covered with finished compost. Use of FC as a covering layer significantly increased the number of days that temperatures in the windrows remained ≥55°C at all locations and in static piles at internal locations. These time-temperature exposures resulted in rapid reduction of inoculated pathogens, and the rate of bacterial reduction was rapid in windrow piles. The sample location significantly influenced the survival of these pathogens at internal locations compared to that at interface locations of piles. Finished compost covering of compost piles aids in the reduction of pathogens during the composting process. PMID:25576620

A prebiotic, Celmanax™, decreases Escherichia coli O157:H7 colonization of bovine cells and feed-associated cytotoxicity in vitro

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Juba Jean

2011-04-01

Full Text Available Abstract Background Escherichia coli O157:H7 is the most common serovar of enterohemorrhagic E. coli associated with serious human disease outbreaks. Cattle are the main reservoir with E. coli O157:H7 inducing hemorrhagic enteritis in persistent shedding beef cattle, however little is known about how this pathogen affects cattle health. Jejunal Hemorrhage Syndrome (JHS has unclear etiology but the pathology is similar to that described for E. coli O157:H7 challenged beef cattle suggestive that E. coli O157:H7 could be involved. There are no effective treatments for JHS however new approaches to managing pathogen issues in livestock using prebiotics and probiotics are gaining support. The first objective of the current study was to characterize pathogen colonization in hemorrhaged jejunum of dairy cattle during natural JHS outbreaks. The second objective was to confirm the association of mycotoxigenic fungi in feeds with the development of JHS and also to identify the presence of potential mycotoxins. The third objective was to determine the impact of a prebiotic, Celmanax™, or probiotic, Dairyman's Choice™ paste, on the cytotoxicity associated with feed extracts in vitro. The fourth objective was to determine the impact of a prebiotic or a probiotic on E. coli O157:H7 colonization of mucosal explants and a bovine colonic cell line in vitro. The final objective was to determine if prebiotic and probiotic feed additives could modify the symptoms that preceded JHS losses and the development of new JHS cases. Findings Dairy cattle developed JHS after consuming feed containing several types of mycotoxigenic fungi including Fusarium culmorum, F. poae, F. verticillioides, F. sporotrichioides, Aspergillusflavus, Penicillium roqueforti, P. crustosum, P. paneum and P. citrinum. Mixtures of Shiga toxin - producing Escherichia coli (STEC colonized the mucosa in the hemorrhaged tissues of the cattle and no other pathogen was identified. The STECs

Impact of Anti-Shiga Toxin Type 2 (Stx2) Neutralizing Antibody on Colonization and Pathogenesis of Escherichia Coli O157:H7 in Mice

Science.gov (United States)

2010-03-17

gulls, pigeons, chickens , turkeys) (41). 19 E. coli O157:H7 carriage by cattle is a common occurrence, although the carriage levels may be...coli O157:H7 22 transmission and infection in food-borne outbreaks can be one of a variety of sources including beef (ground beef, roast beef...rabbits (99). Larger animals that have also been so used, albeit less frequently, include: chickens (20, 272), pigs (297), cows (64), dogs (79), baboons

Influence of surface polysaccharides of Escherichia coli O157:H7 on plant defense response and survival of the human enteric pathogen on Arabidopsis thaliana and lettuce (Lactuca sativa).

Science.gov (United States)

Jang, Hyein; Matthews, Karl R

2018-04-01

This study aimed to determine the influence of bacterial surface polysaccharides (cellulose, colanic acid, and lipopolysaccharide; LPS) on the colonization or survival of Escherichia coli O157:H7 on plants and the plant defense response. Survival of E. coli O157:H7 were evaluated on Arabidopsis thaliana and romaine lettuce as a model plant and an edible crop (leafy vegetable), respectively. The population of the wild-type strain of E. coli O157:H7 on Arabidopsis plants and lettuce was significantly (P lettuce regardless of day post-inoculation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Detection of Escherichia coli O157:H7 in the beef marketed in Malaysia.

Science.gov (United States)

Radu, S; Abdul Mutalib, S; Rusul, G; Ahmad, Z; Morigaki, T; Asai, N; Kim, Y B; Okuda, J; Nishibuchi, M

1998-03-01

Twelve strains of Escherichia coli O157:H7 were isolated from 9 of 25 beef samples purchased from retail stores in Malaysia. These strains produced Shiga toxin 2 with or without Shiga toxin 1 and had the eae gene and a 60-MDa plasmid. The antibiograms and the profiles of the arbitrarily primed PCR of the strains were diverse, suggesting that the strains may have originated from diverse sources.

Enterohemorrhagic Escherichia coli O157 in milk and dairy products from Libya: Isolation and molecular identification by partial sequencing of 16S rDNA

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Aboubaker M. Garbaj

2016-11-01

Full Text Available Aim: The aim of this work was to isolate and molecularly identify enterohemorrhagic Escherichia coli (EHEC O157 in milk and dairy products in Libya, in addition; to clear the accuracy of cultural and biochemical identification as compared with molecular identification by partial sequencing of 16S rDNA for the existing isolates. Materials and Methods: A total of 108 samples of raw milk (cow, she-camel, and goat and locally made dairy products (fermented cow’s milk, Maasora, Ricotta and ice cream were collected from some regions (Janzour, Tripoli, Kremiya, Tajoura and Tobruk in Libya. Samples were subjected to microbiological analysis for isolation of E. coli that was detected by conventional cultural and molecular method using polymerase chain reaction and partial sequencing of 16S rDNA. Results: Out of 108 samples, only 27 isolates were found to be EHEC O157 based on their cultural characteristics (Tellurite-Cefixime-Sorbitol MacConkey that include 3 isolates from cow’s milk (11%, 3 isolates from she-camel’s milk (11%, two isolates from goat’s milk (7.4% and 7 isolates from fermented raw milk samples (26%, isolates from fresh locally made soft cheeses (Maasora and Ricotta were 9 (33% and 3 (11%, respectively, while none of the ice cream samples revealed any growth. However, out of these 27 isolates, only 11 were confirmed to be E. coli by partial sequencing of 16S rDNA and E. coli O157 Latex agglutination test. Phylogenetic analysis revealed that majority of local E. coli isolates were related to E. coli O157:H7 FRIK944 strain. Conclusion: These results can be used for further studies on EHEC O157 as an emerging foodborne pathogen and its role in human infection in Libya.

Agrochemicals indirectly increase survival of E. coli O157:H7 and indicator bacteria by reducing ecosystem services.

Science.gov (United States)

Staley, Zachery R; Rohr, Jason R; Senkbeil, Jacob K; Harwood, Valerie J

Storm water and agricultural runoff frequently contain agrochemicals, fecal indicator bacteria (FIB), and zoonotic pathogens. Entry of such contaminants into aquatic ecosystems may affect ecology and human health. This study tested the hypothesis that the herbicide atrazine and the fungicide chlorothalonil indirectly affect the survival of FIB (Escherichia coli and Enterococcus faecalis) and a pathogen (E. coli O157:H7) by altering densities of protozoan predators or by altering competition from autochthonous bacteria. Streptomycin-resistant E. coli, En. faecalis, and E. coli O157:H7 were added to microcosms composed of Florida river water containing natural protozoan and bacterial populations. FIB, pathogen, and protozoan densities were monitored over six days. Known metabolic inhibitors, cycloheximide and streptomycin, were used to inhibit autochthonous protozoa or bacteria, respectively. The inhibitors made it possible to isolate the effects of predation or competition on survival of allochthonous bacteria, and each treatment increased the survival of FIB and pathogens. Chlorothalonil's effect was similar to that of cycloheximide, significantly reducing protozoan densities and elevating densities of FIB and pathogens relative to the control. Atrazine treatment did not affect protozoan densities, but, through an effect on competition, resulted in significantly greater densities of En. faecalis and E. coli O157:H7. Hence, by reducing predaceous protozoa and bacterial competitors that facilitate purifying water bodies of FIBs and human pathogens, chlorothalonil and atrazine indirectly diminished an ecosystem service of fresh water.

In-package inhibition of E. coli O157:H7 on bulk Romaine lettuce using cold plasma.

Science.gov (United States)

Min, Sea C; Roh, Si Hyeon; Niemira, Brendan A; Boyd, Glenn; Sites, Joseph E; Uknalis, Joseph; Fan, Xuetong

2017-08-01

Dielectric barrier discharge atmospheric cold plasma (DACP) treatment was evaluated for the inactivation of Escherichia coli O157:H7, surface morphology, color, carbon dioxide generation, and weight loss of bulk Romaine lettuce in a commercial plastic clamshell container. The lettuce samples were packed in a model bulk packaging configuration (three rows with either 1, 3, 5, or 7 layers) in the container and treated by DACP (42.6 kV, 10 min). DACP treatment reduced the number of E. coli O157:H7 in the leaf samples in the 1-, 3-, and 5-layer configurations by 0.4-0.8 log CFU/g lettuce, with no significant correlation to the sample location (P > 0.05). In the largest bulk stacking with 7 layers, a greater degree of reduction (1.1 log CFU/g lettuce) was observed at the top layer, but shaking the container increased the uniformity of the inhibition. DACP did not significantly change the surface morphology, color, respiration rate, or weight loss of the samples, nor did these properties differ significantly according to their location in the bulk stack. DACP treatment inhibited E. coli O157:H7 on bulk lettuce in clamshell containers in a uniform manner, without affecting the physical and biological properties and thus holds promise as a post-packaging process for fresh and fresh-cut fruits and vegetables. Published by Elsevier Ltd.

Rapid detection of E. Coli O157:H7 by IFAST and ATP bioluminescence assay for water analysis

CSIR Research Space (South Africa)

Ngamsom, B

2016-10-01

Full Text Available The present investigation reports isolation and detection of E. coli O157:H7 employing a simple and portable microfluidic device based on immiscible filtration assisted by surface tension (IFAST) and adenosine triphosphate (ATP) bioluminescence...

A probabilistic assessment of the contribution of wastewater-irrigated lettuce to Escherichia coli O157:H7 infection risk and disease burden in Kumasi, Ghana.

Science.gov (United States)

Seidu, Razak; Abubakari, Amina; Dennis, Isaac Amoah; Heistad, Arve; Stenstrom, Thor Axel; Larbi, John A; Abaidoo, Robert C

2015-03-01

Wastewater use for vegetable production is widespread across the cities of many developing countries. Studies on the microbial health risks associated with the practice have largely depended on faecal indicator organisms with potential underestimation or overestimation of the microbial health risks and disease burdens. This study assessed the Escherichia coli O157:H7 infection risk and diarrhoeal disease burden measured in disability-adjusted life years (DALYs) associated with the consumption of wastewater-irrigated lettuce in Kumasi, Ghana using data on E. coli O157:H7 in ready-to-harvest, wastewater-irrigated lettuce. Two exposure scenarios - best case and worst case - associated with a single consumption of wastewater-irrigated lettuce were assessed. The assessment revealed wastewater-irrigated lettuce is contributing to the transmission of E. coli O157:H7 in Kumasi, Ghana. The mean E. coli O157:H7 infection risk and DALYs in the wet and dry seasons, irrespective of the exposure scenario, were above the World Health Organization tolerable daily infection risk of 2.7 × 10⁻⁷ per person per day and 10⁻⁶ DALYs per person per year. It is recommended that legislation with clear monitoring indicators and penalties is implemented to ensure that farmers and food sellers fully implement risk mitigating measures.

Prevalence and Antimicrobial Susceptibility Pattern of E. coli O157:H7 Isolated from Traditionally Marketed Raw Cow Milk in and around Asosa Town, Western Ethiopia.

Science.gov (United States)

Disassa, Nigatu; Sibhat, Berhanu; Mengistu, Shimelis; Muktar, Yimer; Belina, Dinaol

2017-01-01

A cross-sectional study was conducted from October 2014 to July 2015 to determine the prevalence and populations of E. coli as well as the prevalence and antimicrobial susceptibility of E. coli O157:H7 isolated from raw milk. Biochemical and serological tests methods were used to confirm E. coli and E. coli O157:H7 and isolates were subjected to antimicrobial susceptibility test using the agar disc diffusion method. Out of 380 raw milk samples examined, 129 (33.9%) and 11 (2.9%) were contaminated with E. coli and E. coli O157:H7, respectively. The highest prevalence was recorded in samples obtained from vendors (39.1%, 4.978 ± 0.180 log 10 /ml) compared with samples from farmers (28.1%, 3.93 ± 0.01 log 10 /ml) with significant differences ( P = 0.02). The frequency of contamination was higher in the samples collected from milk that was stored and transported in plastic containers (39.4%) than in the containers made of stainless steel (23.0%) ( P = 0.002). The antimicrobial susceptibility profile showed that E. coli O157:H7 were resistant to tetracycline (81.8%), streptomycin (81.8%), and kanamycin (63.6%). Milk samples were produced and handled under poor hygienic conditions, stored, and transported in inappropriate containers and under temperature abuse conditions leading to high health risk to the consumers. Additional studies would be needed to establish association between the occurrences of E. coli O157:H7 in raw milk and all the risk factors involved in and around Asosa town.

Effects of thermosonication on the fate of Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice.

Science.gov (United States)

Kiang, W-S; Bhat, R; Rosma, A; Cheng, L-H

2013-04-01

In this study, the effects of thermosonication and thermal treatment on Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice were investigated at 50 and 60°C. Besides, nonlethal injury of Salm. Enteritidis after both treatments was also examined. The highest inactivation was attained with thermosonication at 60°C. The inactivation rate was different for both pathogens, and Salm. Enteritidis was found to be more sensitive to thermosonication than E. coli O157:H7. Salmonella Enteritidis was recovered in all treated samples, except those subjected to more than 5-min thermosonication at 60°C. It was found that the introduction of high-intensity ultrasound enhanced the inactivation of pathogens compared to thermal treatment alone. On the other hand, Salm. Enteritidis was detected in a number of samples following incubation in universal pre-enrichment broth, but no growth was detected after incubation in mango juice. Fruit juices are commonly heat treated to inactivate micro-organisms and enzymes. However, excessive heat treatments may result in undesirable changes in juice quality. Treatment by power ultrasound, a nonthermal technology, may be an alternative processing technique to pasteurize fruit juices. This study highlights the effectiveness of thermosonication in inactivating Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice. © 2012 The Society for Applied Microbiology.

Estimation of Listeria monocytogenes and Escherichia coli O157:H7 prevalence and levels in naturally contaminated rocket and cucumber samples by deterministic and stochastic approaches.

Science.gov (United States)

Hadjilouka, Agni; Mantzourani, Kyriaki-Sofia; Katsarou, Anastasia; Cavaiuolo, Marina; Ferrante, Antonio; Paramithiotis, Spiros; Mataragas, Marios; Drosinos, Eleftherios H

2015-02-01

The aims of the present study were to determine the prevalence and levels of Listeria monocytogenes and Escherichia coli O157:H7 in rocket and cucumber samples by deterministic (estimation of a single value) and stochastic (estimation of a range of values) approaches. In parallel, the chromogenic media commonly used for the recovery of these microorganisms were evaluated and compared, and the efficiency of an enzyme-linked immunosorbent assay (ELISA)-based protocol was validated. L. monocytogenes and E. coli O157:H7 were detected and enumerated using agar Listeria according to Ottaviani and Agosti plus RAPID' L. mono medium and Fluorocult plus sorbitol MacConkey medium with cefixime and tellurite in parallel, respectively. Identity was confirmed with biochemical and molecular tests and the ELISA. Performance indices of the media and the prevalence of both pathogens were estimated using Bayesian inference. In rocket, prevalence of both L. monocytogenes and E. coli O157:H7 was estimated at 7% (7 of 100 samples). In cucumber, prevalence was 6% (6 of 100 samples) and 3% (3 of 100 samples) for L. monocytogenes and E. coli O157:H7, respectively. The levels derived from the presence-absence data using Bayesian modeling were estimated at 0.12 CFU/25 g (0.06 to 0.20) and 0.09 CFU/25 g (0.04 to 0.170) for L. monocytogenes in rocket and cucumber samples, respectively. The corresponding values for E. coli O157:H7 were 0.59 CFU/25 g (0.43 to 0.78) and 1.78 CFU/25 g (1.38 to 2.24), respectively. The sensitivity and specificity of the culture media differed for rocket and cucumber samples. The ELISA technique had a high level of cross-reactivity. Parallel testing with at least two culture media was required to achieve a reliable result for L. monocytogenes or E. coli O157:H7 prevalence in rocket and cucumber samples.

High temperature in combination with UV irradiation enhances horizontal transfer of stx2 gene from E. coli O157:H7 to non-pathogenic E. coli.

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Wan-Fu Yue

Full Text Available Shiga toxin (stx genes have been transferred to numerous bacteria, one of which is E. coli O157:H7. It is a common belief that stx gene is transferred by bacteriophages, because stx genes are located on lambdoid prophages in the E. coli O157:H7 genome. Both E. coli O157:H7 and non-pathogenic E. coli are highly enriched in cattle feedlots. We hypothesized that strong UV radiation in combination with high temperature accelerates stx gene transfer into non-pathogenic E. coli in feedlots.E. coli O157:H7 EDL933 strain were subjected to different UV irradiation (0 or 0.5 kJ/m(2 combination with different temperature (22, 28, 30, 32, and 37 °C treatments, and the activation of lambdoid prophages was analyzed by plaque forming unit while induction of Stx2 prophages was quantified by quantitative real-time PCR. Data showed that lambdoid prophages in E. coli O157:H7, including phages carrying stx2, were activated under UV radiation, a process enhanced by elevated temperature. Consistently, western blotting analysis indicated that the production of Shiga toxin 2 was also dramatically increased by UV irradiation and high temperature. In situ colony hybridization screening indicated that these activated Stx2 prophages were capable of converting laboratory strain of E. coli K12 into new Shiga toxigenic E. coli, which were further confirmed by PCR and ELISA analysis.These data implicate that high environmental temperature in combination with UV irradiation accelerates the spread of stx genes through enhancing Stx prophage induction and Stx phage mediated gene transfer. Cattle feedlot sludge are teemed with E. coli O157:H7 and non-pathogenic E. coli, and is frequently exposed to UV radiation via sunlight, which may contribute to the rapid spread of stx gene to non-pathogenic E. coli and diversity of shiga toxin producing E. coli.

Behavior of Escherichia coli O157:H7 during the manufacture and ripening of Fontina Protected Designation of Origin cheese.

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Bellio, A; Bianchi, D M; Vitale, N; Vernetti, L; Gallina, S; Decastelli, L

2018-06-01

This study was conducted to describe the cheese-making procedure of Fontina Protected Designation of Origin (PDO) cheese and to evaluate the behavior of Escherichia coli O157:H7 during cheese manufacture and ripening. The study was divided into 2 phases: the production of Fontina PDO cheese was monitored at 3 different dairies in the Aosta Valley and an E. coli O157 challenge was conducted at a fourth dairy. The dairies employ different commercial starter cultures for cheese making. The growth of lactic acid bacilli (LAB) and the decrease in pH were slower in the first hours and the LAB concentrations were overall higher in dairy A than in the other 2 dairies. The pH remained substantially unchanged during ripening (range 5.2 to 5.4) in all dairies. Water activity remained constant at around 0.98 until d 21, when it decreased to around 0.97 until d 80 in dairies A and B and 0.95 in dairy E. Whole raw cow milk was used for making Fontina cheese according to the standard procedure. For the experimental production, the milk was inoculated with E. coli O157:H7 at a concentration of approximately 5 log 10 cfu/mL and commercial starter cultures were used according to the Fontina PDO regulation. An increase of 2.0 log 10 cfu/g in E. coli O157:H7 was observed during the first 9.5 h of cheese making, followed by a decrease at 46 h when pH decreased to 5.4 in all trials. Fresh cheeses were salted and held at 10°C for ripening for 80 d. Water activity was decreased to 0.952 at the end of the ripening stage. The LAB concentrations declined gradually; this trend was more marked for the lactobacilli than either the thermophilic or the mesophilic lactococci. The increase in LAB count and the decrease in pH in the first hours did not seem to affect E. coli O157 growth. Ripening was found to inhibit pathogen survival, however, as seen in the reduction of 3 log 10 from the maximum concentration measured during the earlier stages of production. Copyright © 2018 American Dairy

Variation in reactive oxygen species concentration among lettuce types and modulation of their production via PPO during E. coli O157:H7 colonization of injured lettuce leaves(Abstract)

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Minimally processed leafy vegetables are the biggest culprits in produce-linked outbreaks of foodborne illness and E. coli O157:H7 (EcO157) is the predominant causal agent of these epidemics. Harvesting and processing cause plant lesions thus creating new niches for opportunistic colonization of lea...

Classification of non-O157 shiga toxin-producing escherichia coli(STEC) serotypes with hyperspectral microscope imaging

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Non-O157 Shiga toxin-producing Escherichia coli (STEC) strains such as O26, O45, O103, O111, O121 and O145 are recognized as serious outbreak to cause human illness due to their toxicity. A conventional microbiological method for cell counting is laborious and needs long time for the results. Since ...

Determining thermal inactivation of Escherichia coli O157:H7 in fresh compost by simulating early phases of the composting process.

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Singh, Randhir; Kim, Jinkyung; Shepherd, Marion W; Luo, Feng; Jiang, Xiuping

2011-06-01

A three-strain mixture of Escherichia coli O157:H7 was inoculated into fresh dairy compost (ca. 10(7) CFU/g) with 40 or 50% moisture and was placed in an environmental chamber (ca. 70% humidity) that was programmed to ramp from room temperature to selected composting temperatures in 2 and 5 days to simulate the early composting phase. The surviving E. coli O157:H7 population was analyzed by direct plating and enrichment. Optimal and suboptimal compost mixes, with carbon/nitrogen (C/N) ratios of 25:1 and 16:1, respectively, were compared in this study. In the optimal compost mix, E. coli O157:H7 survived for 72, 48, and 24 h in compost with 40% moisture and for 72, 24, and 24 h with 50% moisture at 50, 55, and 60°C, respectively, following 2 days of come-up time (rate of heating up). However, in the suboptimal compost mix, the pathogen survived for 288, 72, and 48 h in compost with 40% moisture and for 240, 72, 24 h in compost with 50% moisture at the same temperatures, respectively. Pathogen survival was longer, with 5 days of come-up time compared with 2 days of come-up. Overall, E. coli O157:H7 was inactivated faster in the compost with 50% moisture than in the compost with 40% at 55 and 60°C. Both moisture and come-up time were significant factors affecting Weibull model parameters. Our results suggest that slow come-up time at the beginning of composting can extend pathogen survival during composting. Additionally, both the C/N ratio and the initial moisture level in the compost mix affect the rate of pathogen inactivation as well.

Evaluation of mericon E. coli O157 Screen Plus and mericon E. coli STEC O-Type Pathogen Detection Assays in Select Foods: Collaborative Study, First Action 2017.05.

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Bird, Patrick; Benzinger, M Joseph; Bastin, Benjamin; Crowley, Erin; Agin, James; Goins, David; Armstrong, Marcia

2018-05-01

QIAGEN mericon Escherichia coli O157 Screen Plus and mericon E. coli Shiga toxin-producing E. coli (STEC) O-Type Pathogen Detection Assays use Real-Time PCR technology for the rapid, accurate detection of E. coli O157 and the "big six" (O26, O45, O103, O111, O121, O145) (non-O157 STEC) in select food types. Using a paired study design, the assays were compared with the U.S. Department of Agriculture, Food Safety Inspection Service Microbiology Laboratory Guidebook Chapter 5.09 reference method for the detection of E. coli O157:H7 in raw ground beef. Both mericon assays were evaluated using the manual and an automated DNA extraction method. Thirteen technicians from five laboratories located within the continental United States participated in the collaborative study. Three levels of contamination were evaluated. Statistical analysis was conducted according to the probability of detection (POD) statistical model. Results obtained for the low-inoculum level test portions produced a difference between laboratories POD (dLPOD) value with a 95% confidence interval of 0.00 (-0.12, 0.12) for the mericon E. coli O157 Screen Plus with manual and automated extraction and mericon E. coli STEC O-Type with manual extraction and -0.01 (-0.13, 0.10) for the mericon E. coli STEC O-Type with automated extraction. The dLPOD results indicate equivalence between the candidate methods and the reference method.

Expression of curli by Escherichia coli O157:H7 strains isolated from patients during outbreaks is different from similar strains isolated from leafy green production environments

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Subbarao Venkata Ravva

2016-12-01

Full Text Available We previously reported that the strains of Escherichia coli O157:H7 (EcO157 that survived longer in austere soil environment lacked expression of curli, a fitness trait linked with intestinal colonization. In addition, the proportion of curli-positive variants of EcO157 decreased with repeated soil exposure. Here we evaluated 84 and 176 clinical strains from outbreaks and sporadic infections in the US, plus 211 animal fecal and environmental strains for curli expression. These shiga-toxigenic strains were from 328 different genotypes, as characterized by multi-locus variable-number tandem-repeat analysis (MLVA. More than half of the fecal strains (human and animal and a significant proportion of environmental isolates (82% were found to lack curli expression. EcO157 strains from several outbreaks linked with the consumption of contaminated apple juice, produce, hamburgers, steak and beef were also found to lack curli expression. Phylogenetic analysis of fecal strains indicates curli expression is distributed throughout the population. However, a significant proportion of animal fecal isolates (84% gave no curli expression compared to human fecal isolates (58%. In addition, analysis of environmental isolates indicated nearly exclusive clustering of curli expression to a single branch of the minimal spanning tree. This indicates that curli expression depends primarily upon the type of environmental exposure and the isolation source, although genotypic differences also contribute to clonal variation in curli. Furthermore, curli-deficient phenotype appears to be a selective trait for survival of EcO157 in agricultural environments.

Transfer and internalisation of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium in cabbage cultivated on contaminated manure-amended soil under tropical field conditions in Sub-Saharan Africa.

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Ongeng, D; Vasquez, G A; Muyanja, C; Ryckeboer, J; Geeraerd, A H; Springael, D

2011-01-31

Surface contamination and internalisation of Escherichia coli O157:H7 and Salmonella Typhimurium in cabbage leaf tissues at harvest (120 days post-transplantation) following amendment of contaminated bovine manure to soil at different times during crop cultivation were investigated under tropical field conditions in the Central Agro-Ecological Zone of Uganda. Fresh bovine manure inoculated with rifampicin-resistant derivatives of non-virulent strains of E. coli O157:H7 and S. Typhimurium was incorporated into the soil to achieve inoculum concentrations of 4 and 7 log CFU/g at the point of transplantation, 56 or 105 days post-transplantation of cabbage seedlings. Frequent sampling of the soil enabled the accurate identification of the survival kinetics in soil, which could be described by the Double Weibull model in all but one of the cases. The persistence of 4 log CFU/g E. coli O157:H7 and S. Typhimurium in the soil was limited, i.e. only inocula applied 105 days post-transplantation were still present at harvest. Moreover, no internalisation in cabbage leaf tissues was observed. In contrast, at the 7 log CFU/g inoculum level, E. coli O157:H7 and S. Typhimurium survived in the soil throughout the cultivation period. All plants (18/18) examined for leaf contamination were positive for E. coli O157:H7 at harvest irrespective of the time of manure application. A similar incidence of leaf contamination was found for S. Typhimurium. On the other hand, only plants (18/18) cultivated on soil amended with contaminated manure at the point of transplantation showed internalised E. coli O157:H7 and S. Typhimurium at harvest. These results demonstrate that under tropical field conditions, the risk of surface contamination and internalisation of E. coli O157:H7 and S. Typhimurium in cabbage leaf tissues at harvest depend on the inoculum concentration and the time of manure application. Moreover, the internalisation of E. coli O157:H7 and S. Typhimurium in cabbage leaf tissues

Occurrence of Coliform and Escherichia coli Contamination and Absence of Escherichia coli O157:H7 on Romaine Lettuce from Retail Stores in the Upper Midwest.

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Greve, Josephine D; Zietlow, Mark S; Miller, Kevin M; Ellingson, Jay L E

2015-09-01

A total of 720 whole, romaine lettuce heads were purchased from retail locations in the Upper Midwest and assessed for coliform and Escherichia coli contamination and for the presence of E. coli O157:H7. During a 16-month period (August 2010 through December 2011), coliform and E. coli counts were enumerated on Petrifilm, and the presence of E. coli O157:H7 and the virulence gene eae was evaluated by real-time PCR (qPCR). Over half (400 of 720) of the lettuce samples were processed with an immunomagnetic separation step before the qPCR assay. All retail lettuce samples were negative for E. coli O157:H7 when tested with the R.A.P.I.D. LT qPCR targeting a region of the O-antigen, and only two (0.28%) were positive for the eae gene when tested with LightCycler qPCR. On Petrifilm, coliform counts of most lettuce samples (96.4%) were between lettuce samples (98.2%) were lettuce heads. These results contribute to the limited recorded data and understanding of microbial contamination of whole romaine lettuce heads purchased from retail locations, specifically revealing the absence of E. coli O157:H7 and low levels of contamination with coliforms and other E. coli strains.

Prevalence and relatedness of Escherichia coli O157:H7 strains in the feces and on the hides and carcasses of U.S. meat goats at slaughter.

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Jacob, M E; Foster, D M; Rogers, A T; Balcomb, C C; Sanderson, M W

2013-07-01

We determined the prevalences of Escherichia coli O157:H7 in feces, hide, and carcasses of meat goats at a U.S. processing plant. Prevalences were 11.1%, 2.7%, and 2.7%, respectively. Sixteen pulsed-field gel electrophoresis (PFGE) subtypes were identified among 49 E. coli O157:H7 isolates, some of which were present on multiple sample types or collection days.

Suppression of Escherichia coli O157:H7 by Dung Beetles (Coleoptera: Scarabaeidae using the lowbush blueberry agroecosystem as a model system.

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Matthew S Jones

Full Text Available Wildlife as a source of microbial contamination is a food safety concern. Deer feces (scat have been determined as a point source for Escherichia coli O157:H7 contamination of fresh produce. The ecological role of the scooped scarab (Onthophagus hecate (Panzer, a generalist dung beetle species common in Maine blueberry fields, was explored as a biological control agent and alternatively as a pathogen vector between deer scat and food. A large-scale field survey of wildlife scat indicated that pathogenic E. coli O157:H7 was present, albeit at a low prevalence (1.9% of samples, n = 318, in the Maine lowbush blueberry agroecosystem. A manipulative field experiment verified that, should contact occur between deer scat and blueberry plants and fruit during the summer, contamination with E. coli O157:H7 can occur and persist for more than 72 h. For both the positive control and an experimental scat inoculation treatment, the levels of the bacterial population decreased over time, but at different rates (treatment x time interaction: F (1.9,18.8 = 358.486, P < 0.0001. The positive control inoculation, which resulted in a higher initial E. coli level on fruit, decayed at a faster rate than inoculation of fruit via scat in the experimental treatment. We conducted 2 laboratory studies to elucidate aspects of dung beetle feeding ecology as it relates to suppression of E. coli O157:H7 from deer scat to lowbush blueberry fruit. In both experiments, dung beetles buried the same amount of scat whether or not the scat was inoculated with the pathogen (F(1,6 = 0.001; P = 0.999 and (F (2,17 = 4.10, P = 0.147. Beetles feeding on E. coli inoculated deer scat were not found to vector the pathogen to fruit. In two studies, beetles lowered the amount of pathogenic E. coli persisting in soils compared to soils without beetles (F (2,9 = 7.757; P = 0.05 and F (2,17 = 8.0621, P = 0.004. Our study suggests that the dung beetle species, Onthophagus hecate, has the potential

INHIBITION OF Escherichia coli O157:H7 CONTAMINATION ON CHICKEN MEAT BY NATURAL VINEGAR PREPARED FROM BANANA PEEL AND COCONUT WATER

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Miskiyah

2016-03-01

Full Text Available The use of vinegar as a natural preservative to inactivate microbial growth in meat was investigated. Vinegar was prepared from banana peel and coconut water, and the efficacy against Escherichia coli O157:H7 was tested. Chicken meat were treated with vinegar solution (equals to 1% acetic acid, acetic acid solutions (1%, and lactic acid solutions (2%, control (distilled water. Samples were soaked with acid solution treatment for 1 minute (1.125:1 w/v; chicken meat: solution treatment. Treated samples were inoculated with E. coli O157:H7 on the surface of the chicken meat, then left for 20 minutes for absorption of bacteria into the meat. Observation was done at 0, 3, 6, 9, and 12 days at low temperature storage, and at 0, 6, 12, 18, 24 hours at room temperature storage. The results showed that banana peel vinegar and coconut water vinegar were effective as natural preservative. In conclusion, the vinegar were potentially inhibited E. coli O157:H7 growth at chicken meat until 12 hours at room temperature storage and 9 days at cold temperatures.