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Sample records for highlights ntp bioassay

  1. Investigation of independence in inter-animal tumor-type occurrences within the NTP rodent-bioassay database

    SciTech Connect

    Bogen, K.T.; Seilkop, S.

    1993-05-01

    Statistically significant elevation in tumor incidence at multiple histologically distinct sites is occasionally observed among rodent bioassays of chemically induced carcinogenesis. If such data are to be relied on (as they have, e.g., by the US EPA) for quantitative cancer potency assessment, their proper analysis requires a knowledge of the extent to which multiple tumor-type occurrences are independent or uncorrelated within individual bioassay animals. Although difficult to assess in a statistically rigorous fashion, a few significant associations among tumor-type occurrences in rodent bioassays have been reported. However, no comprehensive studies of animal-specific tumor-type occurrences at death or sacrifice have been conducted using the extensive set of available NTP rodent-bioassay data, on which most cancer-potency assessment for environmental chemicals is currently based. This report presents the results of such an analysis conducted on behalf of the National Research Council`s Committee on Risk Assessment for Hazardous Air Pollutants. Tumor-type associations among individual animals were examined for {approximately}2500 to 3000 control and {approximately}200 to 600 treated animals using pathology data from 62 B6C3F1 mouse studies and 61 F/344N rat studies obtained from a readily available subset of the NTP carcinogenesis bioassay database. No evidence was found for any large correlation in either the onset probability or the prevalence-at-death or sacrifice of any tumor-type pair investigated in control and treated rats and niece, although a few of the small correlations present were statistically significant. Tumor-type occurrences were in most cases nearly independent, and departures from independence, where they did occur, were small. This finding is qualified in that tumor-type onset correlations were measured only indirectly, given the limited nature of the data analyzed.

  2. NTP Carcinogenesis Bioassay of Diallyl Phthalate (CAS No. 131-17-9) in B6C3F1 Mice (Gavage Study).

    PubMed

    1983-04-01

    Diallyl phthalate is a widely used crosslinking agent for unsaturated polyesters. Diallyl phthalate or diallyl phthalate polyester blends are used primarily as plasticizers and carriers for adding catalysts and pigments to polyesters and in molding, electrical parts, laminating compounds, and impregnation of metal castings. Rubber compounds, epoxy formulations, and polyurethane foams may also contain diallyl phthalate. Annual production of diallyl phthalate in the United States exceeds 5,000 pounds; precise figures are not available. A NTP Carcinogenesis bioassay of diallyl phthalate (99% pure) was conducted by administering 0 (vehicle control), 150, or 300 mg/kg diallyl phthalate in corn oil by gavage, 5 days per week for 103 weeks, to groups of 50 male and 50 female B6C3F1 mice. Survival rates and mean body weights of dosed mice were not different from those of the controls, and pathological lesions unrelated to proliferative changes were not observed. Therefore, a maximally tolerated dose for the purposes of carcinogenicity testing may not have been achieved. The incidences of lymphoma and either lymphoma or leukemia in dosed male mice were no significantly greater than those in the controls according to pairwise comparisons (P=0.051 to P=0.096), but the trend tests were statistically significant by either life table or incidental tumor analysis (P=0.031 to P=0.045). The incidence of lymphomas in the high-dose male mice was 12/50 (24%) in comparison with 6/50 (12%) in the controls. Recent historical incidences at the performing laboratory and in the NTP Bioassay Program were 18/120 (15%) and 71/661 (11%), respectively. Since the incidence of high-dose male mice with leukemia was not significantly greater than that of concurrent or historical controls at the performing laboratory by pairwise comparisons, this marginal increase was considered only to be equivocally related to diallyl phthalate administration. Increased incidences of squamous cell papillomas

  3. NTP Carcinogenesis Bioassay of Propyl Gallate (CAS No. 121-79-9) in F344/N Rats and B6C3F1 Mice (Feed Study).

    PubMed

    1982-12-01

    Propyl gallate is a white to nearly white odorless powder having a slightly bitter taste. Solutions of propyl gallate turn dark in the presence of iron or iron salts. Propyl gallate has been used since 1948 as an antioxidant to stabilize cosmetics, food packaging materials, and foods containing fats. As an additive, it may be found in edible fats, oils, mayonnaise, shortening, baked goods, candy, dried meat, fresh pork sausage, and dried milk, and it is used in hair grooming products, pressure-sensitive adhesives, lubricating oil additives, and transforming oils. A NTP Carcinogenesis bioassay of propyl gallate was conducted by feeding diets containing 6,000 or 12,000 ppm propyl gallate to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex for 103 weeks. Groups of 50 untreated rats and 50 untreated mice of each sex served as controls. Survival of rats and mice was not adversely affected by propyl gallate, but mean body weights of dosed rats and mice of each sex were lower than those of the controls. At 104 weeks, mean body weights of low-and high-dose rats were 4% and 8% lower than those of the controls for males and 11% and 19% lower than those of the controls for females. Similarly, mean body weights of low-and high-dose mice were 5% and 8% lower than those of the controls for males and 11% (both dose groups) lower than those of the controls for females. Thyroid follicular-cell adenomas or carcinomas (combined) occurred in male rats with a statistically significant (P<0.05) positive trend, but the incidences in the dosed groups were not statistically significant in direct comparisons with the control groups. Moreover, the incidence of high-dose male rats with follicular-cell tumors (3/50, 6%) was not statistically different from the historical control rate (14/584, 2.4%) for the laboratory that conducted this bioassay. Rare tumors (an astrocytoma or a glioma) were found in the brains of two low-dose female rats. The incidence of all brain tumors in the

  4. NTP Carcinogenesis Bioassay of L-Ascorbic Acid (Vitamin C) (CAS No. 50-81-7) in F344/N Rats and B6C3F1 Mice (Feed Study).

    PubMed

    1983-03-01

    L-Ascorbic acid is essential for many physiologic functions in animals and humans, mostly biochemical reactions involving oxidation. L-Ascorbic acid is approved for use as a dietary supplement and chemical preservative by the U.S. Food and Drug Administration and is on the FDA's list of substances generally recognized as safe. L-Ascorbic acid may be used in soft drinks as an antioxidant for flavor ingredients, in meat and meat-containing products, for curing and pickling, in flour to improve baking quality, in beer as a stabilizer, in fats and oils as an antioxidant, and in a wide variety of foods for vitamin C enrichment. L-Ascorbic acid may also find use in stain removers, hair waving preparations; plastics manufacture, photography, and water treatment. A NTP Carcinogenesis bioassay of L-ascorbic acid (>97% pure) was conducted by administering diets containing 25,000 or 50,000 ppm L-ascorbic acid to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex for 103 weeks. Controls consisted of 50 untreated rats and untreated mice of each sex. Fifty-thousand ppm is the highest dose recommended for chronic studies. Survival of dosed and control female rats and of dosed and control female mice were comparable. Survival of high-dose male rats was slightly greater than that of the controls (P=0.087). Survival of high-dose male mice was significantly greater (P=0.009) than that of the controls. Throughout most of the study, mean body weights of dosed female rats and dosed female mice were lower than those of the controls. Final body weights were comparable among groups, except for the high-dose female rats (<13%); marginal differences (<8%) were observed for low-dose female rats and for dosed female mice (8%-11%). Food consumption was equivalent among groups. Most observational differences were confined to the female rat. The incidence of low-dose female rats with undifferentiated (mononuclear-cell) leukemias (control, 6/50, 12%; low-dose, 17/50, 34%; high-dose, 12/50, 24

  5. Nuclear Thermal Propulsion (NTP)

    NASA Video Gallery

    NASA's history with nuclear thermal propulsion (NTP) technology goes back to the earliest days of the Agency. The Manned Lunar Rover Vehicle and the Nuclear Engine for Rocket Vehicle Applications p...

  6. NTP comparison process

    NASA Technical Reports Server (NTRS)

    Corban, Robert

    1993-01-01

    The systems engineering process for the concept definition phase of the program involves requirements definition, system definition, and consistent concept definition. The requirements definition process involves obtaining a complete understanding of the system requirements based on customer needs, mission scenarios, and nuclear thermal propulsion (NTP) operating characteristics. A system functional analysis is performed to provide a comprehensive traceability and verification of top-level requirements down to detailed system specifications and provides significant insight into the measures of system effectiveness to be utilized in system evaluation. The second key element in the process is the definition of system concepts to meet the requirements. This part of the process involves engine system and reactor contractor teams to develop alternative NTP system concepts that can be evaluated against specific attributes, as well as a reference configuration against which to compare system benefits and merits. Quality function deployment (QFD), as an excellent tool within Total Quality Management (TQM) techniques, can provide the required structure and provide a link to the voice of the customer in establishing critical system qualities and their relationships. The third element of the process is the consistent performance comparison. The comparison process involves validating developed concept data and quantifying system merits through analysis, computer modeling, simulation, and rapid prototyping of the proposed high risk NTP subsystems. The maximum amount possible of quantitative data will be developed and/or validated to be utilized in the QFD evaluation matrix. If upon evaluation of a new concept or its associated subsystems determine to have substantial merit, those features will be incorporated into the reference configuration for subsequent system definition and comparison efforts.

  7. NATIONAL TOXICOLOGY PROGRAM (NTP) DATA

    EPA Science Inventory

    The National Toxicology Program (NTP) was established in 1978 by the Department of Health and Human Services (DHHS) to coordinate toxicological testing programs within the department, strengthen the science base in toxicology; develop and validate improved testing methods; and pr...

  8. Laser diagnostics for NTP fuel corrosion studies

    NASA Technical Reports Server (NTRS)

    Wantuck, Paul J.; Butt, D. P.; Sappey, A. D.

    1993-01-01

    Viewgraphs and explanations on laser diagnostics for nuclear thermal propulsion (NTP) fuel corrosion studies are presented. Topics covered include: NTP fuels; U-Zr-C system corrosion products; planar laser-induced fluorescence (PLIF); utilization of PLIF for corrosion product characterization of nuclear thermal rocket fuel elements under test; ZrC emission spectrum; and PLIF imaging of ZrC plume.

  9. 76 FR 71037 - Proposed National Toxicology Program (NTP) Review Process for the Report on Carcinogens: Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-16

    ... Federal Register (76 FR 67200) and is available on the NTP Web site ( http://ntp.niehs.nih.gov/go... on the NTP Web site ( http://ntp.niehs.nih.gov/go/rocprocess ) prior to the November 29, 2011... the NTP Web site ( http://ntp.niehs.nih.gov/go/rocprocess ). TTY users should contact the Federal...

  10. Final Report Navajo Transmission Project (NTP)

    SciTech Connect

    Bennie Hoisington; Steven Begay

    2006-09-14

    The Diné Power Authority is developing the Navajo Transmission Project (NTP) to relieve the constraints on the transmission of electricity west of the Four Corners area and to improve the operation flexibility and reliability of the extra-high-voltage transmission system in the region. The NTP creates the wholesale transmission capacity for more economical power transfers, sales, and purchases in the region. It will facilitate the development of Navajo energy resources, improve economic conditions on the Navajo Nation as well as allow DPA to participate in the western electrical utility industry.

  11. Aerobrake concepts for NTP systems study

    NASA Technical Reports Server (NTRS)

    Cruz, Manuel I.

    1992-01-01

    Design concepts are described for landing large spacecraft masses on the Mars surface in support of manned missions with interplanetary transportation using Nuclear Thermal Propulsion (NTP). Included are the mission and systems analyses, trade studies and sensitivity analyses, design analyses, technology assessment, and derived requirements to support this concept. The mission phases include the Mars de-orbit, entry, terminal descent, and terminal touchdown. The study focuses primarily on Mars surface delivery from orbit after Mars orbit insertion using an NTP. The requirements associated with delivery of logistical supplies, habitats, and other equipment on minimum energy Earth to Mars transfers are also addressed in a preliminary fashion.

  12. 75 FR 12244 - National Toxicology Program (NTP); Office of Liaison, Policy and Review; Meeting of the NTP Board...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-15

    ...Pursuant to Public Law 92-463, notice is hereby given of a meeting of the NTP Board of Scientific Counselors (BSC). The BSC is a Federally chartered, external advisory group composed of scientists from the public and private sectors that provides primary scientific oversight to the NTP Director and evaluates the scientific merit of the NTP's intramural and collaborative...

  13. 76 FR 8370 - National Toxicology Program (NTP); Office of Liaison, Policy and Review; Meeting of the NTP Board...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-14

    ...Pursuant to Public Law 92-463, notice is hereby given of a meeting of the NTP Board of Scientific Counselors (BSC). The BSC is a federally chartered, external advisory group composed of scientists from the public and private sectors that provides primary scientific oversight to the NTP Director and evaluates the scientific merit of the NTP's intramural and collaborative...

  14. 75 FR 64311 - National Toxicology Program (NTP); Office of Liaison, Policy and Review Meeting of the NTP Board...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-19

    ...Pursuant to Public Law 92-463, notice is hereby given of a meeting of the NTP Board of Scientific Counselors (BSC). The BSC is a federally chartered, external advisory group composed of scientists from the public and private sectors that provides primary scientific oversight to the NTP Director and evaluates the scientific merit of the NTP's intramural and collaborative...

  15. Summary of Chemically Induced Pulmonary Lesions in the National Toxicology Program (NTP) Toxicology and Carcinogenesis Studies

    PubMed Central

    Dixon, Darlene; Herbert, Ronald A.; Kissling, Grace E.; Brix, Amy E.; Miller, Rodney A.; Maronpot, Robert R.

    2009-01-01

    The lung is the second most common target site of neoplasia of chemicals tested by the National Toxicology Program (NTP). Of all peer-reviewed NTP studies to date (N = 545), a total of sixty-four chemicals in sixty-six reports produced significant site-specific neoplasia in the lungs of rats and/or mice. Of the studies associated with lung tumor induction, approximately 35% were inhalation and 35% were gavage studies, with dosed-feed, dosed-water, topical, intraperitoneal, or in utero routes of chemical administration accounting for 18%, 6%, 3%, 1%, and 1% of the studies, respectively. The most commonly induced lung tumors were alveolar/bronchiolar (A/B) adenoma and/or carcinoma for both species. The most frequently observed nonneoplastic lesions included hyperplasia and inflammation in both species. The liver was the most common primary site of origin of metastatic lesions to the lungs of mice; however, skin was most often the primary site of origin of metastatic lesions to the lungs of rats. In summary, A/B adenoma and carcinoma were the most frequently diagnosed chemically induced tumors in the lungs of both rats and mice in the NTP toxicology and carcinogenesis bioassays, and hyperplasia and inflammation were the most common nonneoplastic changes observed. PMID:18441259

  16. 76 FR 51034 - Availability of Draft NTP Monograph on Potential Developmental Effects of Cancer Chemotherapy...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-17

    ... (available at http://ntp.niehs.nih.gov/go/36639 ) that will be peer reviewed by an NTP Peer Review Panel at a... available, will be posted on the NTP Web site ( http://ntp.niehs.nih.gov/go/36639 ) or may be requested in... ( http://ntp.niehs.nih.gov/go/36639 ) by October 12, 2011, to facilitate access to the NIEHS campus....

  17. Chemical-induced atrial thrombosis in NTP rodent studies.

    PubMed

    Yoshizawa, Katsuhiko; Kissling, Grace E; Johnson, Jo Anne; Clayton, Natasha P; Flagler, Norris D; Nyska, Abraham

    2005-01-01

    Cardiac thrombosis, one of the causes of sudden death throughout the world, plays a principal role in several cardiovascular diseases, such as myocardial infarction and stroke in humans. Data from studies of induction of chemical thrombosis in rodents help to identify substances in our environment that may contribute to cardiac thrombosis. Results for more than 500 chemicals tested in rodents in 2-year bioassays have been published as Technical Reports of the National Toxicology Program (NTP) http://ntp-server.niehs.nih.gov/index. We evaluated atrial thrombosis induced by these chemical exposures and compared it to similarly induced lesions reported in the literature. Spontaneous rates of cardiac thrombosis were determined for control Fischer 344 rats and B6C3F1 mice: 0% in rats and mice in 90-day studies and, in 2-year studies, 0.7% in both genders of mice, 4% in male rats, and 1% in female rats. Incidences of atrial thrombosis were increased in high-dosed groups involving 13 compounds (incidence rate: 20-100%): 2-butoxyethanol, C.I. Direct Blue 15, bis(2-chloroethoxy)methane, diazoaminobenzene, diethanolamine, 3,3'-dimethoxybenzidine dihydrochloride, hexachloroethane, isobutene, methyleugenol, oxazepam, C.I. Pigment Red 23, C.I. Acid Red 114, and 4,4'-thiobis(6-t-butyl-m-cresol). The main localization of spontaneously occurring and chemically induced thromboses occurred in the left atrium. The literature survey suggested that chemical-induced atrial thrombosis might be closely related to myocardial injury, endothelial injury, circulatory stasis, hypercoagulability, and impaired atrial mechanical activity, such as atrial fibrillation, which could cause stasis of blood within the left atrial appendage, contributing to left atrial thrombosis. Supplementary data referenced in this paper are not printed in this issue of Toxicologic Pathology. They are available as downloadable files at http://taylorandfrancis.metapress.com/openurl.asp?genre=journal&issn=0192-6233. To

  18. 76 FR 8741 - National Toxicology Program (NTP): Office of Liaison, Policy, and Review; Availability of Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... a Meeting SUMMARY: The NTP announces the availability of draft NTP Technical Reports (TRs; available... meeting. DATES: The meeting to review the draft NTP TRs will be held on April 5, 2011. The draft NTP TRs... any other correspondence on the draft TRs should be sent to Danica Andrews, NIEHS, P.O. Box 12233,...

  19. 75 FR 73085 - National Toxicology Program (NTP): Office of Liaison, Policy, and Review; Availability of Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-29

    ... a Meeting. SUMMARY: The NTP announces the availability of draft NTP Technical Reports (TRs... meeting. DATES: The meeting to review the draft NTP TRs will be held on January 26, 2011. The draft NTP TRs will be available for public comment by December 8, 2010. The deadline to submit written...

  20. A Research Reactor Concept to Support NTP Development

    NASA Technical Reports Server (NTRS)

    Eades, Michael J.; Blue, T. E.; Gerrish, Harold P.; Hardin, Leroy A.

    2014-01-01

    In support of efforts for research into the design and development of man rated Nuclear Thermal Propulsion (NTP), the National Aeronautics and Space Administration (NASA), Marshall Space Flight Center (MSFC), is evaluating the potential for building a Nuclear Regulatory Commission (NRC) licensed NTP based research reactor (NTPRR). The proposed NTPRR would be licensed by NASA and operated jointly by NASA and university partners. The purpose of the NTPRR would be used to perform further research into the technologies and systems needed for a successful NTP project and promote nuclear training and education.

  1. An overview of tested and analyzed NTP concepts

    NASA Technical Reports Server (NTRS)

    Walton, James T.

    1991-01-01

    If we buy into the goals of the Space Exploration Initiative (SEI) and accept that they are worthy of the hefty investment of our tax dollars, then we must begin to evaluate the technologies which enable their attainment. The main driving technology is the propulsion systems; for interplanetary missions, the safest and most affordable is a Nuclear Thermal Propulsion (NTP) system. An overview is presented of the NTP systems which received detailed conceptual design and, for several, testing.

  2. 75 FR 66766 - National Toxicology Program (NTP); Office of Liaison, Policy and Review; Meeting of the NTP Board...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-29

    ... meeting was published on October 19, 2010, in the Federal Register (75 FR 201) and is available on the BSC meeting page ( http://ntp.niehs.nih.gov/go/165 ). The guidelines and deadlines published in this...

  3. Integrated System Modeling for Nuclear Thermal Propulsion (NTP)

    NASA Technical Reports Server (NTRS)

    Ryan, Stephen W.; Borowski, Stanley K.

    2014-01-01

    Nuclear thermal propulsion (NTP) has long been identified as a key enabling technology for space exploration beyond LEO. From Wernher Von Braun's early concepts for crewed missions to the Moon and Mars to the current Mars Design Reference Architecture (DRA) 5.0 and recent lunar and asteroid mission studies, the high thrust and specific impulse of NTP opens up possibilities such as reusability that are just not feasible with competing approaches. Although NTP technology was proven in the Rover / NERVA projects in the early days of the space program, an integrated spacecraft using NTP has never been developed. Such a spacecraft presents a challenging multidisciplinary systems integration problem. The disciplines that must come together include not only nuclear propulsion and power, but also thermal management, power, structures, orbital dynamics, etc. Some of this integration logic was incorporated into a vehicle sizing code developed at NASA's Glenn Research Center (GRC) in the early 1990s called MOMMA, and later into an Excel-based tool called SIZER. Recently, a team at GRC has developed an open source framework for solving Multidisciplinary Design, Analysis and Optimization (MDAO) problems called OpenMDAO. A modeling approach is presented that builds on previous work in NTP vehicle sizing and mission analysis by making use of the OpenMDAO framework to enable modular and reconfigurable representations of various NTP vehicle configurations and mission scenarios. This approach is currently applied to vehicle sizing, but is extensible to optimization of vehicle and mission designs. The key features of the code will be discussed and examples of NTP transfer vehicles and candidate missions will be presented.

  4. NTP-CERHR EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF 2-BROMOPROPANE

    EPA Science Inventory

    The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences (NIEHS) established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in order to provide timely, unbiased, scientifically sound evaluations of human and exper...

  5. 76 FR 68461 - Meeting of the National Toxicology Program (NTP) Board of Scientific Counselors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-04

    ...Pursuant to Public Law 92-463, notice is hereby given of a meeting of the NTP Board of Scientific Counselors (BSC). The BSC is a federally chartered, external advisory group composed of scientists from the public and private sectors that provides primary scientific oversight to the NTP and evaluates the scientific merit of the NTP's intramural and collaborative...

  6. 77 FR 24714 - Meeting of the National Toxicology Program (NTP) Board of Scientific Counselors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-25

    ...Pursuant to Public Law 92-463, notice is hereby given of a meeting of the NTP Board of Scientific Counselors (BSC). The BSC is a federally chartered, external advisory group composed of scientists from the public and private sectors that provides primary scientific oversight to the NTP and evaluates the scientific merit of the NTP's intramural and collaborative...

  7. NTP system definition and comparison process for SEI

    SciTech Connect

    Corban, R.R. )

    1993-01-20

    The concept definition, trade-offs, and ultimate selection of a nuclear thermal propulsion (NTP) system that will enable the Space Exploration Initiative (SEI) missions to Mars will require a rigorous systems engineering approach. A systems engineering process to provide a consistent comparison has been established to allow for evolving SEI mission requirements, level of concept definition and changing customer'' requirements, while continuing to improve the process as more data becomes available. All concepts will be evaluated against an established baseline NTP system to compare system benefits and merits. Establishing the evaluation criteria is extremely challenging and critical to the evaluation and selection process. Quality function deployment (QFD) will be utilized to provide structure and focus in obtaining the critical needs and attributes of the NTP system. System performance, cost, and risk analysis tools will be integrated into the process to provide the quantitative data required to allow for an informative decision on concept and technology decisions. This process will initiate the framework for design and development of a robust, reliable, cost effective NTP engine within NASA's philosophy for space systems to be developed faster, better, and cheaper.''

  8. Nanovehicles based Bioassay Labels

    SciTech Connect

    Liu, Guodong; Wang, Jun; Wu, Hong; Lin, Ying-Ying; Lin, Yuehe

    2007-04-01

    In this article, we review recent advances of our group in nanoparticle labels based bioassay. Apoferritin and silica nanoparticles have been used as nanovehicles to load large amount of markers for highly sensitive bioassay. Markers loaded apoferritin, apoferritin-templated metallic phosphate nanoparticles, and poly [guanine] coated silica nanoparticles have been prepared, characterized and used as labels for highly sensitive bioassay of protein and DNA. Dissociation and reconstitution characteristics at different pH as well as the special cavity structure of apoferritin nanovehicle provides a simple and convenient route to prepare versatile nanoparticle labels and avoid the complicated and tedious synthesis process of conventional nanoparticle labels. The optical and electrochemical characteristics of the prepared nanoparticle labels are easily controlled by loading different optical or electrochemical markers. Additionally, the use of apoferritin nanovehicle as template for synthesis of metallic phosphate nanoparticle labels offers fast route to prepare uniform-size metallic nanoparticle labels for electrochemical bioassay and avoids the traditional harsh dissolution conditions to dissolve metallic nanoparticle tags (that is, the strong-acid dissolution of quantum dots and gold nanoparticles) during the stripping analysis step. Silica nanoparticle has also been used as nanovehicle to carry thousands of poly [guanine] tracers, which was used to enhance the oxidation current of Ru(bpy)32+, resulting in enhanced sensitivity of electrochemical immunoassay. The new nanovehicle-based labels have been used for highly sensitive electrochemical detection of DNA and protein biomarkers, such as tumor necrosis factor-alpha (TNF-a). The high sensitivity and selectivity make these labels a useful addition to the armory of nanoparticle-based bioassay. The new nanovehicles based labels hold great promise for multiplex protein and DNA detection and for enhancing the sensitivity

  9. Nuclear Thermal Propulsion (NTP) Development Activities at the NASA Marshall Space Flight Center - 2006 Accomplishments

    NASA Technical Reports Server (NTRS)

    Ballard, Richard O.

    2007-01-01

    In 2005-06, the Prometheus program funded a number of tasks at the NASA-Marshall Space Flight Center (MSFC) to support development of a Nuclear Thermal Propulsion (NTP) system for future manned exploration missions. These tasks include the following: 1. NTP Design Develop Test & Evaluate (DDT&E) Planning 2. NTP Mission & Systems Analysis / Stage Concepts & Engine Requirements 3. NTP Engine System Trade Space Analysis and Studies 4. NTP Engine Ground Test Facility Assessment 5. Non-Nuclear Environmental Simulator (NTREES) 6. Non-Nuclear Materials Fabrication & Evaluation 7. Multi-Physics TCA Modeling. This presentation is a overview of these tasks and their accomplishments

  10. 77 FR 1707 - National Toxicology Program (NTP) Final Process for Preparation of the Report on Carcinogens (RoC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-11

    ... October 31, 2011, the NTP released its proposed process for preparation of the RoC (76 FR 67200 and 76 FR..., and presented a revised process at the NTP Board of Scientific Counselors public meeting (76 FR 68461... available on the NTP Web site ( http://ntp.niehs.nih.gov/go/rocprocess ) or by contacting Dr. Ruth Lunn...

  11. 76 FR 61704 - Availability of Draft NTP Monograph on the Health Effects of Low-Level Lead; Request for Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-05

    ... Health Effects of Low-level Lead (available at http://ntp.niehs.nih.gov/go/36639 ) that will be peer... studies on health effects associated with low blood lead levels ( http://ntp.niehs.nih.gov/go/36639 ) by... online at the NTP Web site ( http://ntp.niehs.nih.gov/go/36639 ) by November 10, 2011, to...

  12. 75 FR 21003 - National Toxicology Program (NTP); Office of Liaison, Policy and Review Meeting of the NTP Board...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ....nih.gov/go/29353 ) that was announced in the Federal Register on April 16, 2007 (72 FR 18999). On... review for the 12th RoC (69 FR 28940, 69 FR 62276, 70 FR 60548, 72 FR 26394). Publication of the RoC is... extended review process for the 12th RoC (72 FR 18999). Although the NTP initially planned to review...

  13. NTP system simulation and detailed nuclear engine modeling

    NASA Technical Reports Server (NTRS)

    Anghaie, Samim

    1993-01-01

    The topics are presented in viewgraph form and include the following: nuclear thermal propulsion (NTP) & detailed nuclear engine modeling; modeling and engineering simulation of nuclear thermal rocket systems; nuclear thermal rocket simulation system; INSPI-NTVR core axial flow profiles; INSPI-NTRV core axial flow profiles; specific impulse vs. chamber pressure; turbine pressure ratio vs. chamber pressure; NERVA core axial flow profiles; P&W XNR2000 core axial flow profiles; pump pressure rise vs. chamber pressure; streamline of jet-induced flow in cylindrical chamber; flow pattern of a jet-induced flow in a chamber; and radiative heat transfer models.

  14. Bioassay for assessing marine contamination

    SciTech Connect

    Lapota, D.; Copeland, H.; Mastny, G.; Rosenberger, D.; Duckworth, D.

    1996-03-01

    The Qwiklite bioassay, developed by the laboratory at NCCOSC, is used as a biological tool to gauge the extent of environmental contamination. Some species of marine phytoplankton produce bioluminescence. The Qwiklite bioassay determines acute response and chronic effects of a wide variety of toxicants upon bioluminescent dinotlagellates by measuring their light output after exposure.

  15. Prediction of rodent carcinogenicity bioassays from molecular structure using inductive logic programming

    SciTech Connect

    King, R.D.; Srinivasan, A.

    1996-10-01

    The machine learning program Progol was applied to the problem of forming the structure-activity relationship (SAR) for a set of compounds tested for carcinogenicity in rodent bioassays by the U.S. National Toxicology Program (NTP). Progol is the first inductive logic programming (ILP) algorithm to use a fully relational method for describing chemical structure in SARs, based on using atoms and their bond connectivities. Progol is well suited to forming SARs for carcinogenicity as it is designed to produce easily understandable rules (structural alerts) for sets of noncongeneric compounds. The Progol SAR method was tested by prediction of a set of compounds that have been widely predicted by other SAR methods (the compounds used in the NTP`s first round of carcinogenesis predictions). For these compounds no method (human or machine) was significantly more accurate than Progol. Progol was the most accurate method that did not use data from biological tests on rodents (however, the difference in accuracy is not significant). The Progol predictions were based solely on chemical structure and the results of tests for Salmonella mutagenicity. Using the full NTP database, the prediction accuracy of Progol was estimated to be 63% ({+-}3%) using 5-fold cross validation. A set of structural alerts for carcinogenesis was automatically generated and the chemical rationale for them investigated-these structural alerts are statistically independent of the Salmonella mutagenicity. Carcinogenicity is predicted for the compounds used in the NTP`s second round of carcinogenesis predictions. The results for prediction of carcinogenesis, taken together with the previous successful applications of predicting mutagenicity in nitroaromatic compounds, and inhibition of angiogenesis by suramin analogues, show that Progol has a role to play in understanding the SARs of cancer-related compounds. 29 refs., 2 figs., 4 tabs.

  16. Prediction of rodent carcinogenicity bioassays from molecular structure using inductive logic programming.

    PubMed Central

    King, R D; Srinivasan, A

    1996-01-01

    The machine learning program Progol was applied to the problem of forming the structure-activity relationship (SAR) for a set of compounds tested for carcinogenicity in rodent bioassays by the U.S. National Toxicology Program (NTP). Progol is the first inductive logic programming (ILP) algorithm to use a fully relational method for describing chemical structure in SARs, based on using atoms and their bond connectivities. Progol is well suited to forming SARs for carcinogenicity as it is designed to produce easily understandable rules (structural alerts) for sets of noncongeneric compounds. The Progol SAR method was tested by prediction of a set of compounds that have been widely predicted by other SAR methods (the compounds used in the NTP's first round of carcinogenesis predictions). For these compounds no method (human or machine) was significantly more accurate than Progol. Progol was the most accurate method that did not use data from biological tests on rodents (however, the difference in accuracy is not significant). The Progol predictions were based solely on chemical structure and the results of tests for Salmonella mutagenicity. Using the full NTP database, the prediction accuracy of Progol was estimated to be 63% (+/- 3%) using 5-fold cross validation. A set of structural alerts for carcinogenesis was automatically generated and the chemical rationale for them investigated- these structural alerts are statistically independent of the Salmonella mutagenicity. Carcinogenicity is predicted for the compounds used in the NTP's second round of carcinogenesis predictions. The results for prediction of carcinogenesis, taken together with the previous successful applications of predicting mutagenicity in nitroaromatic compounds, and inhibition of angiogenesis by suramin analogues, show that Progol has a role to play in understanding the SARs of cancer-related compounds. PMID:8933051

  17. 48 CFR 1516.603-2 - What are the requirements for use of an NTP?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... for use of an NTP? 1516.603-2 Section 1516.603-2 Federal Acquisition Regulations System ENVIRONMENTAL..., and Letter Contracts 1516.603-2 What are the requirements for use of an NTP? (a) An EPA FCS 1102....S.C. 9604(a)(1), and the National Oil and Hazardous Substances Pollution Contingency Plan (40...

  18. 48 CFR 1516.603-2 - What are the requirements for use of an NTP?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... for use of an NTP? 1516.603-2 Section 1516.603-2 Federal Acquisition Regulations System ENVIRONMENTAL..., and Letter Contracts 1516.603-2 What are the requirements for use of an NTP? (a) An EPA FCS 1102....S.C. 9604(a)(1), and the National Oil and Hazardous Substances Pollution Contingency Plan (40...

  19. 48 CFR 1516.603-2 - What are the requirements for use of an NTP?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... for use of an NTP? 1516.603-2 Section 1516.603-2 Federal Acquisition Regulations System ENVIRONMENTAL..., and Letter Contracts 1516.603-2 What are the requirements for use of an NTP? (a) An EPA FCS 1102....S.C. 9604(a)(1), and the National Oil and Hazardous Substances Pollution Contingency Plan (40...

  20. NTP-CERHR Expert Panel Report on the reproductive and developmental toxicity of hydroxyurea

    EPA Science Inventory

    The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences (NIEHS) established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June 1998. The purpose of CERHR is to provide timely, unbiased, scientifically sound e...

  1. 76 FR 77832 - Availability of Draft NTP Technical Reports; Request for Comments; Announcement of a Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... announces the availability of seven draft NTP Technical Reports (TRs) tentatively scheduled for peer review... meeting. DATES: The meeting will be held on February 8-9, 2012. The draft NTP TRs should be available for... on the draft TRs should be sent to Danica Andrews, Designated Federal Official, Office of...

  2. Conceptual design of the french MAPS NTP cargo shuttle based on a particle bed reactor

    SciTech Connect

    Lenain, R.; Linet, F.L.; Poitevin, Y.; Proust, E.; Raepsaet, X.; Bernard, S.; Duchesne, A.

    1996-03-01

    MAPS, a 3-years study program on NTP has been launched at CEA in 1994 following the conclusions of a preliminary scoping study of an NTP system for earth to moon orbit cargo shuttle missions. This paper presents the main results obtained after one year of studies, and gives an outline of the future work. {copyright} {ital 1996 American Institute of Physics.}

  3. 75 FR 76995 - National Toxicology Program (NTP); Center for the Evaluation of Risks to Human Reproduction...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-10

    ... established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in 1998 (63 FR 68782) to... Reproduction (CERHR); NTP Workshop: Role of Environmental Chemicals in the Development of Diabetes and Obesity... (collectively referred to as ``substances'') cause adverse effects on reproduction and development and...

  4. NTP-CERHR Expert Panel Report on the Reproductive and Developmental Toxicity of Bisphenol A

    EPA Science Inventory

    The National Toxicology Program (NTP)1 established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June 1998. The purpose of the CERHR is to provide timely, unbiased, scientifically sound evaluations of the potential for adverse effects on reproduction...

  5. BIOASSAY VESSEL FAILURE ANALYSIS

    SciTech Connect

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  6. Impact of Environmental Enrichment Devices on NTP In Vivo Studies.

    PubMed

    Churchill, Sheba R; Morgan, Daniel L; Kissling, Grace E; Travlos, Gregory S; King-Herbert, Angela P

    2016-02-01

    The goal of this study was to determine whether the use of nesting material or polycarbonate shelters as enrichment devices would have an impact on end points commonly measured during the conduct of the National Toxicology Program (NTP) 13-week studies. The study design was consistent with the NTP 13-week toxicity studies. Harlan Sprague-Dawley (HSD) rats and their offspring and B6C3F1/N mice were assigned to control (unenriched) and enriched experimental groups. Body weight, food and water consumption, behavioral observations, fecal content, clinical pathology, gross pathology, organ weights, and histopathology were evaluated. Enriched male mice and male and female rats exhibited decreased feed intake without a subsequent decrease in body weight; this may have been the result of the nesting material reducing the effect of cold stress, thereby allowing for more efficient use of feed. There were statistical differences in some hematological parameters; however, these were not considered physiologically relevant since all values were within the normal range. Gross pathology and histopathological findings were background changes and were not considered enrichment-related. Nesting material and shelters were used frequently and consistently and allowed animals to display species-typical behavior. There was no significant impact on commonly measured end points in HSD rats and B6C3F1/N mice given enrichment devices. PMID:26873679

  7. Pulse-based non-thermal plasma (NTP) disrupts the structural characteristics of bacterial biofilms.

    PubMed

    Ferrell, James R; Shen, Fan; Grey, Scott F; Woolverton, Christopher J

    2013-01-01

    Bacterial biofilms were constructed in vitro with two pathogenic strains of Pseudomonas aeruginosa and Staphylococcus aureus using a modified, novel sequential bioreactor system. The structure and stability of bacterial biofilms were evaluated following exposure to non-thermal plasma (NTP) discharge. Mathematical software was used to determine structural changes as biofilms grew over the course of 7 days. Statistical modeling was also performed to assess the ability of NTP to affect the development of the biofilms over different periods of time. Several structural characteristics were significantly affected by NTP discharge whereas others were unaffected. Changes in the three-dimensional structure of the biofilm following introduction of NTP was not limited to one period of development. The mechanism for this phenomenon is not understood but is likely to be a dual, synergistic effect due to the composition of the reactive species and other plasma-associated molecules isolated previously in the NTP discharge used in this study. PMID:23682750

  8. 76 FR 36923 - Meeting of the National Toxicology Program (NTP) Board of Scientific Counselors (BSC): Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-23

    ...: The NTP BSC meeting, scheduled for July 21, 2011, and announced in the Federal Register (76 FR 28785... HUMAN SERVICES Meeting of the National Toxicology Program (NTP) Board of Scientific Counselors (BSC): Notice of Cancellation AGENCY: National Toxicology Program (NTP), National Institute of...

  9. Research Highlights

    ERIC Educational Resources Information Center

    Australian Council for Educational Research, 2004

    2004-01-01

    This document is an annual publication documenting developments in the Australian Council for Educational Research (ACER)'s research programs for the previous year. The 2004 edition highlights research on the following themes: (1) Helping international schools measure achievement; (2) Evaluating Australian teachers; (3) Tests of reading…

  10. Raising Nuclear Thermal Propulsion (NTP) Technology Readiness Above 3

    NASA Technical Reports Server (NTRS)

    Gerrish, Harold P., Jr.

    2014-01-01

    NTP development is currently supported by the NASA program office "Advanced Exploration Systems". The concept is a main propulsion option being considered for human missions to Mars in the 2030's. Major NTP development took place in the 1960's and 1970's under the Rover/NERVA program. The technology had matured to TRL 6 and was preparing to go to TRL 7 with a prototype flight engine before the program was cancelled. Over the last 40 years, a variety of continuations started, but only lasted a few years each. The Rover/NERVA infrastructure is almost all gone. The only remains are a few pieces of hardware, final reports and a few who worked the Rover/NERVA. Two types of nuclear fuel are being investigated to meet the current engine design specific impulse of 900 seconds compared to approximately 850 seconds demonstrated during Rover/NERVA. One is a continuation of composite fuel with new coatings to better control mid-band corrosion. The other type is a CERMET fuel made of Tungsten and UO2. Both fuels are being made from Rover/NERVA lessons learned, but with slightly different recipes to increase fuel endurance at higher operating temperatures. The technology readiness level (TRL) of these current modified reactor fuels is approximately TRL 3. To keep the development cost low and help mature the TRL level past 4 quickly, a few special non-nuclear test facilities have been made to test surrogate fuel, with depleted uranium, as coupons and full length elements. Both facilities utilize inductive heating and are licensed to handle depleted uranium. TRL 5 requires exposing the fuel to a nuclear environment and TRL 6 requires a prototype ground or flight engine system test. Currently, three different NTP ground test facility options are being investigated: exhaust scrubber, bore hole, and total exhaust containment. In parallel, a prototype flight demonstration test is also being studied. The first human mission to Mars in the 2030's is currently 2033. For an advanced

  11. Prostaglandins, bioassay and inflammation

    PubMed Central

    Flower, R J

    2006-01-01

    The formation of the British Pharmacological Society coincided almost exactly with a series of ground-breaking studies that ushered in an entirely new field of research – that of lipid mediator pharmacology. For many years following their chemical characterisation, lipids were considered only to be of dietary or structural importance. From the 1930s, all this changed – slowly at first and then more dramatically in the 1970s and 1980s with the emergence of the prostaglandins (PGs), the first intercellular mediators to be clearly derived from lipids, in a dynamic on-demand system. The PGs exhibit a wide range of biological activities that are still being evaluated and their properties underlie the action of one of the world's all-time favourite medicines, aspirin, as well as its more modern congeners. This paper traces the development of the PG field, with particular emphasis on the skilful utilisation of the twin techniques of bioassay and analytical chemistry by U.K. and Swedish scientists, and the intellectual interplay between them that led to the award of a joint Nobel Prize to the principal researchers in the PG field, half a century after the first discovery of these astonishingly versatile mediators. PMID:16402103

  12. Structural Model of RNA Polymerase II Elongation Complex with Complete Transcription Bubble Reveals NTP Entry Routes

    PubMed Central

    Zhang, Lu; Silva, Daniel-Adriano; Pardo-Avila, Fátima; Wang, Dong; Huang, Xuhui

    2015-01-01

    The RNA polymerase II (Pol II) is a eukaryotic enzyme that catalyzes the synthesis of the messenger RNA using a DNA template. Despite numerous biochemical and biophysical studies, it remains elusive whether the “secondary channel” is the only route for NTP to reach the active site of the enzyme or if the “main channel” could be an alternative. On this regard, crystallographic structures of Pol II have been extremely useful to understand the structural basis of transcription, however, the conformation of the unpaired non-template DNA part of the full transcription bubble (TB) is still unknown. Since diffusion routes of the nucleoside triphosphate (NTP) substrate through the main channel might overlap with the TB region, gaining structural information of the full TB is critical for a complete understanding of Pol II transcription process. In this study, we have built a structural model of Pol II with a complete transcription bubble based on multiple sources of existing structural data and used Molecular Dynamics (MD) simulations together with structural analysis to shed light on NTP entry pathways. Interestingly, we found that although both channels have enough space to allow NTP loading, the percentage of MD conformations containing enough space for NTP loading through the secondary channel is twice higher than that of the main channel. Further energetic study based on MD simulations with NTP loaded in the channels has revealed that the diffusion of the NTP through the main channel is greatly disfavored by electrostatic repulsion between the NTP and the highly negatively charged backbones of nucleotides in the non-template DNA strand. Taken together, our results suggest that the secondary channel is the major route for NTP entry during Pol II transcription. PMID:26134169

  13. Future NTP Development Synergy Leveraged from Current J-2X Engine Development

    NASA Technical Reports Server (NTRS)

    Ballard, Richard O.

    2008-01-01

    This paper is a discussion of how the many long-lead development elements required for the realization of a future nuclear thermal propulsion (NTP) system can be effectively leveraged from the ongoing work being conducted on the J-2X engine program for the Constellation Program. Development studies conducted to date for NTP forward planning have identified a number of technical areas that will require advancement to acceptable technology readiness levels (TRLs) before they can be utilized in NTP system development. These include high-temperature, high-area ratio nozzle extension; long-life, low-NPSP. turbomachinery; and low-boiloff propellant management; and a qualified nuclear fuel element. The current J-2X program is working many of these areas that can be leveraged to support NTP development in a highly compatible and synergistic fashion. In addition to supporting technical development, there are other programmatic issues being worked in the J-2X program that can be leveraged by a future NTP development program. These include compliance with recently-evolved space system requirements such as human-rating, fault tolerance and fracture control. These and other similar mandatory system requirements have been adopted by NASA and can result in a significant technical impact beyond elevation of the root technologies required by NTP. Finally, the exploitation of experience, methodologies, and procedures developed by the J-2X program in the areas of verification, qualification, certification, altitude simulation testing, and facility definition will be especially applicable to a future NTP system. The similarities in system mission (in-space propulsion) and operational environment (vacuum, zero-gee) between J-2X and NTP make this highly synergistic. Thus, it can be $hown that the collective benefit of leveraging experience and technologies developed during the J-2X program can result in significant savings in development cost and schedule for NTP.

  14. Future NTP Development Synergy Leveraged from Current J-2X Engine Development

    SciTech Connect

    Ballard, Richard O.

    2008-01-21

    This paper is a discussion of how the many long-lead development elements required for the realization of a future nuclear thermal propulsion (NTP) system can be effectively leveraged from the ongoing work being conducted on the J-2X engine program for the Constellation Program. Development studies conducted to date for NTP forward planning have identified a number of technical areas that will require advancement to acceptable technology readiness levels (TRLs) before they can be utilized in NTP system development. These include high-temperature, high-area ratio nozzle extension; long-life, low-NPSP turbomachinery; and low-boiloff propellant management, and a qualified nuclear fuel element. The current J-2X program is working many of these areas that can be leveraged to support NTP development in a highly compatible and synergistic fashion. In addition to supporting technical development, there are other programmatic issues being worked in the J-2X program that can be leveraged by a future NTP development program. These include compliance with recently-evolved space system requirements such as human-rating, fault tolerance and fracture control. These and other similar mandatory system requirements have been adopted by NASA and can result in a significant technical impact beyond elevation of the root technologies required by NTP. Finally, the exploitation of experience, methodologies, and procedures developed by the J-2X program in the areas of verification, qualification, certification, altitude simulation testing, and facility definition will be especially applicable to a future NTP system. The similarities in system mission (in-space propulsion) and operational environment (vacuum, zero-gee) between J-2X and NTP make this highly synergistic. Thus, it can be shown that the collective benefit of leveraging experience and technologies developed during the J-2X program can result in significant savings in development cost and schedule for NTP.

  15. Future NTP Development Synergy Leveraged from Current J-2X Engine Development

    NASA Astrophysics Data System (ADS)

    Ballard, Richard O.

    2008-01-01

    This paper is a discussion of how the many long-lead development elements required for the realization of a future nuclear thermal propulsion (NTP) system can be effectively leveraged from the ongoing work being conducted on the J-2X engine program for the Constellation Program. Development studies conducted to date for NTP forward planning have identified a number of technical areas that will require advancement to acceptable technology readiness levels (TRLs) before they can be utilized in NTP system development. These include high-temperature, high-area ratio nozzle extension; long-life, low-NPSP turbomachinery; and low-boiloff propellant management, and a qualified nuclear fuel element. The current J-2X program is working many of these areas that can be leveraged to support NTP development in a highly compatible and synergistic fashion. In addition to supporting technical development, there are other programmatic issues being worked in the J-2X program that can be leveraged by a future NTP development program. These include compliance with recently-evolved space system requirements such as human-rating, fault tolerance and fracture control. These and other similar mandatory system requirements have been adopted by NASA and can result in a significant technical impact beyond elevation of the root technologies required by NTP. Finally, the exploitation of experience, methodologies, and procedures developed by the J-2X program in the areas of verification, qualification, certification, altitude simulation testing, and facility definition will be especially applicable to a future NTP system. The similarities in system mission (in-space propulsion) and operational environment (vacuum, zero-gee) between J-2X and NTP make this highly synergistic. Thus, it can be shown that the collective benefit of leveraging experience and technologies developed during the J-2X program can result in significant savings in development cost and schedule for NTP.

  16. Sensitive bioassay for detection of biologically active ricin in food

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential use of ricin as an agent of biological warfare highlights the need to develop fast and effective methods to detect biologically active ricin. The current “gold standard” for ricin detection is an in vivo mouse bioassay; however, this method is not practical to test on a large number of...

  17. 77 FR 48995 - Draft National Toxicology Program (NTP) Monograph on Developmental Effects and Pregnancy Outcomes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... Developmental Effects and Pregnancy Outcomes Associated With Cancer Chemotherapy Use During Pregnancy; Request... Pregnancy Outcomes Associated with Cancer Chemotherapy Use during Pregnancy (available by August 14, 2012... NTP Monograph on Developmental Effects and Pregnancy Outcomes Associated with Cancer Chemotherapy...

  18. 76 FR 28785 - Meeting of the National Toxicology Program (NTP) Board of Scientific Counselors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-18

    ...: National Toxicology Program (NTP), National Institute of Environmental Health Sciences (NIEHS), National... of Environmental Chemicals in the Development of Diabetes and Obesity Collaborative Transgenerational... from recognized authorities knowledgeable in fields such as toxicology, pharmacology,...

  19. 76 FR 67200 - Proposed National Toxicology Program (NTP) Review Process for the Report on Carcinogens: Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-31

    ... HUMAN SERVICES National Institutes of Health Proposed National Toxicology Program (NTP) Review Process... the National Toxicology Program (DNTP), National Institute of Environmental Health Sciences (NIEHS... Toxicology Program. BILLING CODE 4140-01-P...

  20. Current Ground Test Options for Nuclear Thermal Propulsion (NTP)

    NASA Technical Reports Server (NTRS)

    Gerrish, Harold P., Jr.

    2014-01-01

    About 20 different NTP engines/ reactors were tested from 1959 to 1972 as part of the Rover and Nuclear Engine for Rocket Vehicle Application (NERVA) program. Most were tested in open air at test cell A or test cell C, at the Nevada Test Site (NTS). Even after serious engine breakdowns of the reactor (e.g., Phoebus 1A), the test cells were cleaned up for other engine tests. The engine test stand (ETS) was made for high altitude (approximately 1 psia) testing of an NTP engine with a flight configuration, but still had the exhaust released to open air. The Rover/NERVA program became aware of new environmental regulations which would prohibit the release of any significant quantity of radioactive particulates and noble gases into the open air. The nuclear furnace (NF-1) was the last reactor tested before the program was cancelled in 1973, but successfully demonstrated a scrubber concept on how to filter the NTP exhaust. The NF-1 was demonstrated in the summer of 1972. The NF-1 used a 44MW reactor and operated each run for approximately 90 minutes. The system cooled the hot hydrogen exhaust from the engine with a water spray before entering a particle filter. The exhaust then passed through a series of heat exchangers and water separators to help remove water from the exhaust and further reduce the exhaust temperatures. The exhaust was next prepared for the charcoal trap by passing through a dryer and effluent cooler to bring exhaust temperatures close to liquid nitrogen. At those low temperatures, most of the noble gases (e.g., Xe and Kr made from fission products) get captured in the charcoal trap. The filtered hydrogen is finally passed through a flare stack and released to the air. The concept was overall successful but did show a La plating on some surfaces and had multiple recommendations for improvement. The most recent detailed study on the NTP scrubber concept was performed by the ARES Corporation in 2006. The concept is based on a 50,000 lbf thrust engine

  1. A particle bed reactor based NTP in the 112,500 N thrust class

    SciTech Connect

    Ludewig, H.; Powell, J.R.; Lazareth, O.W. Jr.; Todosow, M.

    1993-04-01

    This paper discusses the application of a Particle bed Reactor (PBR) to a 112,500 N thrust Nuclear Thermal Propulsion (NTP) Engine. The method of analysis is described, followed by a presentation of the results. It is concluded that the PBR would result in a very competitive NTP engine. In addition, due to the high power densities possible with a PBR, high thrust/weight ratios are possible. This conclusion can be used to satisfy a variety of mission goals.

  2. A particle bed reactor based NTP in the 112,500 N thrust class

    SciTech Connect

    Ludewig, H.; Powell, J.R.; Lazareth, O.W. Jr.; Todosow, M. )

    1993-01-20

    This paper discusses the application of a Particle Bed Reactor (PBR) to a 112,500 N thrust Nuclear Thermal Propulsion (NTP) Engine. The method of analysis is described, followed by a presentation of the results. It is concluded that the PBR would result in a very competitive NTP engine. In addition, due to the high power densities possible with a PBR, high thrust/weight ratios are possible. This conclusion can be used to satisfy a variety of mission goals.

  3. Operational mode analysis of the maps NTP system

    SciTech Connect

    Linet, F.L.; Bernard, S.; Carruge, D.; Poitevin, Y.; Raepsaet, X.

    1996-03-01

    Within the framework of the french NTP program MAPS, the analysis of the (start-up/shut-down) transient sequences whose negative impact on the specific impulsion Isp is important, requires the evaluation of the hydrogen system performance and consequently the development of a simulation computer program. This work induces a preliminary evaluation of the hydrogen system performance under nominal operating conditions. A first approach of the transient operating mode has been simultaneously performed; more specifically the evolution of the core during a shut-down sequence has been studied in order to improve the residual power evacuation and optimize necessary hydrogen amounts for cooling. Furthermore the {open_quote}{open_quote}SIMAPS{close_quote}{close_quote} computer program based on the 3D thermohydraulic code {open_quote}{open_quote}FLICA 4{close_quote}{close_quote} is being developed to analyze transient process and its benchmarking under nominal conditions is under way. Its summary presentation is given in conclusion. {copyright} {ital 1996 American Institute of Physics.}

  4. Prediction of rodent nongenotoxic carcinogenesis: evaluation of biochemical and tissue changes in rodents following exposure to nine nongenotoxic NTP carcinogens.

    PubMed Central

    Elcombe, Clifford R; Odum, Jenny; Foster, John R; Stone, Susan; Hasmall, Susan; Soames, Anthony R; Kimber, Ian; Ashby, John

    2002-01-01

    We studied nine presumed nongenotoxic rodent carcinogens, as defined by the U.S. National Toxicology Program (NTP), to determine their ability to induce acute or subacute biochemical and tissue changes that may act as useful predictors of nongenotoxic rodent carcinogenesis. The chemicals selected included six liver carcinogens (two of which are peroxisome proliferators), three thyroid gland carcinogens, and four kidney carcinogens. We administered the chemicals (diethylhexyl phthalate, cinnamyl anthranilate, chlorendic acid, 1,4-dichlorobenzene, monuron, ethylene thiourea, diethyl thiourea, trimethyl thiourea, and d-limonene to the same strains of mice and rats used in the original NTP bioassays (nine chemicals to rats and seven to mice). Selected tissues (liver, thyroid gland, and kidney) were collected from groups of animals at 7, 28, and 90 days for evaluation. Tissue changes selected for study were monitored for all of the test groups, irrespective of the specificity of the carcinogenic responses observed in those tissues. This allowed us to assess both the carcinogen specificity and the carcinogen sensitivity of the events being monitored. We studied relative weight, cell labeling indices, and pathologic changes such as hypertrophy in all tissues; a range of cytochrome P450 enzymes and palmitoyl coenzyme A oxidase in the liver; changes in the levels of plasma total triiodothyronine, total thyroxine, and thyroid-stimulating hormone (TSH) as markers of thyroid gland function; and hyaline droplet formation, tubular basophilia, and the formation of granular casts in the kidney. There were no single measurements that alerted specifically to the carcinogenicity of the agents to the rodent liver, thyroid gland, or kidney. However, in the majority of cases, the chemical induction of cancer in a tissue was preceded by a range of biochemical/morphologic changes, most of which were moderately specific for a carcinogenic outcome, and some of which were highly specific for

  5. Sediment bioassays with oyster larvae

    SciTech Connect

    Chapman, P.M.; Morgan, J.D.

    1983-10-01

    Tests with naturally-occurring sediments are rare and sediment testing methodology is not standardized. The authors present a simple methodology for undertaking sediment bioassays with oyster larvae, and present data from a recent study to prove the utility of this method.

  6. UNIFYING SCALER FOR BIOASSAY TESTS

    EPA Science Inventory

    An extensive set of interlaboratory root bioassay data was unified using centroids of individual tests as scalers. It is shown that the dose response obeys a first order differential equation with the constant of the equation related to the sensitivity of the dose response relati...

  7. Proceedings of the 2013 Joint JSTP/NTP Satellite Symposium

    PubMed Central

    Elmore, Susan A.; Hoenerhoff, Mark; Katsuta, Osamu; Kokoshima, Hiroko; Maronpot, Robert; Nagai, Hiroaki; Satoh, Hiroshi; Tanaka, Yasuhiro; Tochitani, Tomoaki; Tsuchiya, Seiichiro; Yoshizawa, Katsuhiko

    2013-01-01

    The first joint Japanese Society of Toxicologic Pathology (JSTP) and National Toxicology Program (NTP) Satellite Symposium, entitled “Pathology Potpourri,” was held on January 29th at Okura Frontier Hotel in Tsukuba, Ibaraki, Japan, in advance of the JSTP’s 29th Annual Meeting. The goal of this Symposium was to present current diagnostic pathology or nomenclature issues to the toxicologic pathology community. This article presents summaries of the speakers’ presentations, including diagnostic or nomenclature issues that were presented, select images that were used for audience voting or discussion, and the voting results. Some lesions and topics covered during the symposium include: treatment-related atypical hepatocellular foci of cellular alteration in B6C3F1 mice; purulent ventriculoencephalitis in a young BALB/c mouse; a subcutaneous malignant schwannoma in a RccHan:WIST rat; spontaneous nasal septum hyalinosis/eosinophilic substance in B6C3F1 mice; a rare pancreatic ductal cell adenoma in a young Lewis rat; eosinophilic crystalline pneumonia in a transgenic mouse model; hyaline glomerulopathy in two female ddY mice; treatment-related intrahepatic erythrocytes in B6C3F1 mice; treatment-related subendothelial hepatocytes in B6C3F1 mice; spontaneous thyroid follicular cell vacuolar degeneration in a cynomolgus monkey; congenital hepatic fibrosis in a 1-year-old cat; a spontaneous adenocarcinoma of the middle ear in a young Crl:CD(SD) rat; and finally a series of cases illustrating some differences between cholangiofibrosis and cholangiocarcinoma in Sprague Dawley and F344 rats. PMID:23914068

  8. Environmental monitoring using genetic bioassays

    SciTech Connect

    Lewtas, J.

    1989-01-01

    Environmental monitoring has evolved over the last ten years toward providing data more useful for exposure and risk assessment. The objective of many monitoring studies in the 1960s and 1970s was to monitor concentrations of pollutants including environmental mutagens at ambient locations, such as roof tops and in large bodies of water, where the pollutants would be well mixed and represent a homogeneous sample. In the 1980s, a number of studies focused on assessing the emission of mutagens from various sources. Now the emphasis has shifted to monitoring human exposure to environmental mutagens and to understanding which sources and factors lead to increased exposure and potential cancer risk. The chapter briefly reviews advances in genetic bioassay methods for environmental monitoring and focuses on approaches to integrating genetic bioassay methods with environmental-monitoring studies.

  9. NTP-CERHR monograph on the potential human reproductive and developmental effects of bisphenol A.

    PubMed

    Shelby, Michael D

    2008-09-01

    The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) conducted an evaluation of the potential for bisphenol A to cause adverse effects on reproduction and development in humans. The CERHR Expert Panel on Bisphenol A completed its evaluation in August 2007. CERHR selected bisphenol A for evaluation because of the: widespread human exposure; public concern for possible health effects from human exposures; high production volume; evidence of reproductive and developmental toxicity in laboratory animal studies Bisphenol A (CAS RN: 80-05-7) is a high production volume chemical used primarily in the production of polycarbonate plastics and epoxy resins. Polycarbonate plastics are used in some food and drink containers; the resins are used as lacquers to coat metal products such as food cans, bottle tops, and water supply pipes. To a lesser extent bisphenol A is used in the production of polyester resins, polysulfone resins, polyacrylate resins, and flame retardants. In addition, bisphenol A is used in the processing of polyvinyl chloride plastic and in the recycling of thermal paper. Some polymers used in dental sealants and tooth coatings contain bisphenol A. The primary source of exposure to bisphenol A for most people is assumed to occur through the diet. While air, dust, and water (including skin contact during bathing and swimming) are other possible sources of exposure, bisphenol A in food and beverages accounts for the majority of daily human exposure. The highest estimated daily intakes of bisphenol A in the general population occur in infants and children. The results of this bisphenol A evaluation are published in an NTP-CERHR Monograph that includes the (1) NTP Brief and (2) Expert Panel Report on the Reproductive and Developmental Toxicity of Bisphenol A. Additional information related to the evaluation process, including the peer review report for the NTP Brief and public comments received on the draft NTP

  10. NTP-CERHR monograph on the potential human reproductive and developmental effects of methylphenidate.

    PubMed

    2005-08-01

    The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) conducted an evaluation of the potential for methylphenidate to cause adverse effects on reproduction and development in humans. Methylphenidate was selected for evaluation because of 1) widespread usage in children, 2) availability of developmental studies in children and experimental animals, and 3) public concern about the effect of this stimulant on child development. Methylphenidate is a central nervous system stimulant approved by the U.S. Food and Drug Administration for the treatment of attention deficit hyperactivity disorder (ADHD) in persons 6 years of age and older and for narcolepsy. The results of this evaluation on methylphenidate are published in an NTP-CERHR monograph which includes: 1) the NTP Brief, 2) the Expert Panel Report on the Reproductive and Developmental Toxicity of Methylphenidate, and 3) public comments received on the Expert Panel Report. As stated in the NTP Brief, the NTP reached the following conclusions regarding the possible effects of exposure to methylphenidate on human development and reproduction. First, there is negligible concern for methylphenidate-induced tics and movement disorders. This conclusion is based on studies showing that children treated with therapeutic doses of methylphenidate have no evidence of movement disorders or tics due to the medication. Second, there is minimal concern for methylphenidate-induced growth restriction. This conclusion is based on growth restriction being observed in animal studies only at high doses of methylphenidate using a non-therapeutic route of exposure. The effect on growth was reversible. Finally, there are insufficient data to draw conclusions on 1) an association between methylphenidate therapy in pregnant women and pregnancy loss and 2) possible reproductive effects of methylphenidate in humans. NTP-CERHR monographs are transmitted to federal and state agencies, interested

  11. A review comparing deoxyribonucleoside triphosphate (dNTP) concentrations in the mitochondrial and cytoplasmic compartments of normal and transformed cells

    PubMed Central

    Gandhi, Vishal V.; Samuels, David C.

    2011-01-01

    The deoxyribonucleoside triphosphate (dNTP) pools that support the replication of mitochondrial DNA are physically separated from the rest of the cell by the double membrane of the mitochondria. Perturbed homeostasis of mitochondrial dNTP pools is associated with a set of severe diseases collectively termed mitochondrial DNA depletion syndromes. The degree of interaction of the mitochondrial dNTP pools with the corresponding dNTP pools in the cytoplasm is currently not clear. We reviewed the literature on previously reported simultaneous measurements of mitochondrial and cytoplasmic deoxyribonucleoside triphosphate pools to investigate and quantify the extent of the influence of the cytoplasmic nucleotide metabolism on mitochondrial dNTP pools. We converted the reported measurements to concentrations creating a catalog of paired mitochondrial and cytoplasmic dNTP concentration measurements. Over experiments from multiple laboratories, dNTP concentrations in the mitochondria are highly correlated with dNTP concentrations in the cytoplasm in normal cells in culture (Pearson R = 0.79, p = 3 × 10-7) but not in transformed cells. For dTTP and dATP there was a strong linear relationship between the cytoplasmic and mitochondrial concentrations in normal cells. From this linear model we hypothesize that the salvage pathway within the mitochondrion is only capable of forming a concentration of approximately 2 μM of dTTP and dATP, and that higher concentrations require transport of deoxyribonucleotides from the cytoplasm. PMID:21774628

  12. A review of whole animal bioassays of the carcinogenic potential of naphthalene.

    PubMed

    North, D Warner; Abdo, Kamal M; Benson, Janet M; Dahl, Alan R; Morris, John B; Renne, Roger; Witschi, Hanspeter

    2008-07-01

    This report provides a summary of deliberations conducted under the charge for members of Module A participating in the Naphthalene State-of-the-Science Symposium (NS3), Monterey, CA, October 9-12, 2006. Whole animal bioassays have been performed by the National Toxicology Program in mice and rats to ascertain the carcinogenic potential of naphthalene by inhalation exposure. A statistically significant increased incidence of pulmonary alveolar/bronchiolar adenoma (a benign lesion), was observed among female mice; an observed increase among the males did not reach statistical significance. No nasal tumors were observed in either sex. A tumorigenic response was observed in both sexes of rats, in males an increased incidence of nasal respiratory epithelium adenoma (a benign rather than malignant lesion) and in females, olfactory epithelial neuroblastoma. Interpretations of these studies vary. On the one hand, evidence of extensive non-neoplastic response in both sexes of both species indicates cytotoxicity occurred at all doses, and strongly suggests that cytotoxicity played a significant role in the tumor responses observed in the target tissues. On the other hand, olfactory epithelial neuroblastoma has rarely been observed in NTP bioassays. This review seeks to develop a consensus understanding of the scientific evidence provided by these studies, taking into account that they have been used as the basis for quantitative human cancer risk assessment, and suggests scientific studies that, if performed, could resolve scientific uncertainties. PMID:18364246

  13. Nanomaterial-Based Electrochemical Biosensors and Bioassays

    SciTech Connect

    Liu, Guodong; Mao, Xun; Gurung, Anant; Baloda, Meenu; Lin, Yuehe; He, Yuqing

    2010-08-31

    This book chapter summarizes the recent advance in nanomaterials for electrochemical biosensors and bioassays. Biofunctionalization of nanomaterials for biosensors fabrication and their biomedical applications are discussed.

  14. NTP-CERHR EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF ACRYLAMIDE

    EPA Science Inventory

    The National Toxicology Program Center for the Evaluation of Risks to Human Reproduction (NTP-CERHR) convened an expert panel in May 2004 to evaluate acrylamide. The report of the expert panel, prepared in accordance with CERHR Guidelines, provides a detailed summary of all publi...

  15. Mitochondrial DNA Replication Defects Disturb Cellular dNTP Pools and Remodel One-Carbon Metabolism.

    PubMed

    Nikkanen, Joni; Forsström, Saara; Euro, Liliya; Paetau, Ilse; Kohnz, Rebecca A; Wang, Liya; Chilov, Dmitri; Viinamäki, Jenni; Roivainen, Anne; Marjamäki, Päivi; Liljenbäck, Heidi; Ahola, Sofia; Buzkova, Jana; Terzioglu, Mügen; Khan, Nahid A; Pirnes-Karhu, Sini; Paetau, Anders; Lönnqvist, Tuula; Sajantila, Antti; Isohanni, Pirjo; Tyynismaa, Henna; Nomura, Daniel K; Battersby, Brendan J; Velagapudi, Vidya; Carroll, Christopher J; Suomalainen, Anu

    2016-04-12

    Mitochondrial dysfunction affects cellular energy metabolism, but less is known about the consequences for cytoplasmic biosynthetic reactions. We report that mtDNA replication disorders caused by TWINKLE mutations-mitochondrial myopathy (MM) and infantile onset spinocerebellar ataxia (IOSCA)-remodel cellular dNTP pools in mice. MM muscle shows tissue-specific induction of the mitochondrial folate cycle, purine metabolism, and imbalanced and increased dNTP pools, consistent with progressive mtDNA mutagenesis. IOSCA-TWINKLE is predicted to hydrolyze dNTPs, consistent with low dNTP pools and mtDNA depletion in the disease. MM muscle also modifies the cytoplasmic one-carbon cycle, transsulfuration, and methylation, as well as increases glucose uptake and its utilization for de novo serine and glutathione biosynthesis. Our evidence indicates that the mitochondrial replication machinery communicates with cytoplasmic dNTP pools and that upregulation of glutathione synthesis through glucose-driven de novo serine biosynthesis contributes to the metabolic stress response. These results are important for disorders with primary or secondary mtDNA instability and offer targets for metabolic therapy. PMID:26924217

  16. NTP-CERHR EXPERT PANEL REPORT ON REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF METHYLPHENIDATE.

    EPA Science Inventory

    A manuscript describes the results of an expert panel meeting of the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR). The purpose CERHR is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects on...

  17. NTP-CERHR EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF AMPHETAMINE AND METHAMPHETAMINE.

    EPA Science Inventory

    A manuscript describes the results of an expert panel meeting of the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR). The purpose CERHR is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects ...

  18. 77 FR 22321 - National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-13

    ...\\ NIEHS/NTP,\\2\\ U.S. Environmental Protection Agency (EPA),\\3\\ and U.S. Food and Drug Administration (FDA....niehs.nih.gov/go/28213 . \\3\\ http://www.epa.gov/ncct/Tox21/ . \\4\\ http://www.fda.gov/ . The Tox21 HTS... efficient, high throughput in vitro assays. Tox21 also aims to expand the ability to screen...

  19. dNTP-dependent Conformational Transitions in the Fingers Subdomain of Klentaq1 DNA Polymerase

    PubMed Central

    Rothwell, Paul J.; Allen, William J.; Sisamakis, Evangelos; Kalinin, Stanislav; Felekyan, Suren; Widengren, Jerker; Waksman, Gabriel; Seidel, Claus A. M.

    2013-01-01

    DNA polymerases are responsible for the accurate replication of DNA. Kinetic, single-molecule, and x-ray studies show that multiple conformational states are important for DNA polymerase fidelity. Using high precision FRET measurements, we show that Klentaq1 (the Klenow fragment of Thermus aquaticus DNA polymerase 1) is in equilibrium between three structurally distinct states. In the absence of nucleotide, the enzyme is mostly open, whereas in the presence of DNA and a correctly base-pairing dNTP, it re-equilibrates to a closed state. In the presence of a dNTP alone, with DNA and an incorrect dNTP, or in elevated MgCl2 concentrations, an intermediate state termed the “nucleotide-binding” state predominates. Photon distribution and hidden Markov modeling revealed fast dynamic and slow conformational processes occurring between all three states in a complex energy landscape suggesting a mechanism in which dNTP delivery is mediated by the nucleotide-binding state. After nucleotide binding, correct dNTPs are transported to the closed state, whereas incorrect dNTPs are delivered to the open state. PMID:23525110

  20. Nanoparticle-Based Biosensors and Bioassays

    SciTech Connect

    Liu, Guodong; Wang, Jun; Lin, Yuehe; Wang, Joseph

    2007-10-11

    In this book chapter, we review the recent advances in nanoparticles based bioassay. The nanoparticles include quantum dots, silica nanoparticles and apoferritin nanoparticles. The new nanoparticles-based labels hold great promise for multiplex protein and DNA detection and for enhancing the sensitivity of other bioassays.

  1. The legacy of the F344 rat as a cancer bioassay model (a retrospective summary of three common F344 rat neoplasms).

    PubMed

    Maronpot, Robert R; Nyska, Abraham; Foreman, Jennifer E; Ramot, Yuval

    2016-09-01

    The Fischer 344 (F344) rat was used by the National Toxicology Program (NTP) for over 5 decades for toxicity and carcinogenicity studies. However, in 2006, the NTP decided to switch to a different rat stock due largely to high background control incidences of Leydig cell tumors (LCTs) and mononuclear cell leukemia (MNCL), also known as large granular lymphocytic (LGL) leukemia. In the current review, we aim (1) to provide a summary of NTP bioassays with treatment-associated effects involving MNCL and LCTs in addition to male F344-specific tunica vaginalis mesothelioma (TVM); (2) to describe important pathobiological differences between these F344 rat tumor responses and similar target tissue-tumor response in humans; and (3) to present the NTP reasons for switching away from the F344 rat. We show that due to the highly variable background incidence of F344 MNCL, more reliance on historical control data than is usual for most tumor responses is warranted to evaluate potential effect of any chemical treatment in this rat strain. The high spontaneous incidence of LCTs in the testes of male F344 rats has made this tumor endpoint of little practical use in identifying potential testicular carcinogenic responses. TVM responses in F344 rats have a biological plausible relationship to LCTs unlike TVM in humans. Given their high spontaneous background incidence and species-specific biology, we contend that MNCL and LCT, along with TVM responses, in F344 rat carcinogenicity studies are inappropriate tumor types for human health risk assessment and lack relevance in predicting human carcinogenicity. PMID:27278595

  2. Regulatory Forum Opinion Piece*: New testing paradigms for reproductive and developmental toxicity - The NTP Modified One generation study and OECD 443

    PubMed Central

    Foster, Paul M.D.

    2014-01-01

    The NTP has developed a new flexible study design, termed the modified one generation reproduction (MOG) study. The MOG study will encompass measurements of developmental and reproductive toxicity parameters as well as enable the setting of appropriate dose levels for a cancer bioassay through evaluation of target organ toxicity which is based on test article exposure that starts during gestation. This study design is compared and contrasted with the new OECD 443 test guideline, the extended one generation reproduction study. The MOG study has a number of advantages, with a focus on F1 animals, the generation of adequately powered, robust datasets which include both pre-and postnatal developmental toxicity information, and the measurement of effects on reproductive structure and function in the same animals. This new study design does not employ the use of internal triggers in the design structure for the use of animals already on test and is also consistent with the principles of the 3R’s. PMID:24862797

  3. Regulatory Forum opinion piece: New testing paradigms for reproductive and developmental toxicity--the NTP modified one generation study and OECD 443.

    PubMed

    Foster, Paul M D

    2014-12-01

    The National Toxicology Program (NTP) has developed a new flexible study design, termed the modified one generation (MOG) reproduction study. The MOG study will encompass measurements of developmental and reproductive toxicity parameters as well as enable the setting of appropriate dose levels for a cancer bioassay through evaluation of target organ toxicity that is based on test article exposure that starts during gestation. This study design is compared and contrasted with the new Organization for Economic Co-operation and Development (OECD) 443 test guideline, the extended one generation reproduction study. The MOG study has a number of advantages, with a focus on F 1 animals, the generation of adequately powered, robust data sets that include both pre and postnatal developmental toxicity information, and the measurement of effects on reproductive structure and function in the same animals. This new study design does not employ the use of internal triggers in the design structure for the use of animals already on test and is also consistent with the principles of the 3R's. PMID:24862797

  4. Bioassays Based on Molecular Nanomechanics

    DOE PAGESBeta

    Majumdar, Arun

    2002-01-01

    Recent experiments have shown that when specific biomolecular interactions are confined to one surface of a microcantilever beam, changes in intermolecular nanomechanical forces provide sufficient differential torque to bend the cantilever beam. This has been used to detect single base pair mismatches during DNA hybridization, as well as prostate specific antigen (PSA) at concentrations and conditions that are clinically relevant for prostate cancer diagnosis. Since cantilever motion originates from free energy change induced by specific biomolecular binding, this technique is now offering a common platform for label-free quantitative analysis of protein-protein binding, DNA hybridization DNA-protein interactions, and in general receptor-ligandmore » interactions. Current work is focused on developing “universal microarrays” of microcantilever beams for high-throughput multiplexed bioassays.« less

  5. NTP-CERHR monograph on the potential human reproductive and developmental effects of amphetamines.

    PubMed

    2005-07-01

    The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) conducted an evaluation of the potential for amphetamines to cause adverse effects on reproduction and development in humans. Amphetamines evaluated were D- and D,L-amphetamine and methamphetamine. Amphetamine is approved by the U.S. Food and Drug Administration for the treatment of attention deficit hyperactivity disorder (ADHD) in persons over 3 years of age and narcolepsy; methamphetamine is approved for the treatment of ADHD in persons 6 years of age and older and for short-term treatment of obesity. Amphetamines were selected for evaluation because of 1) widespread usage in children, 2) availability of developmental studies in children and experimental animals, and 3) public concern about the effect of this stimulant on child development. The results of this evaluation on amphetamines are published in an NTP-CERHR monograph which includes: 1) the NTP Brief, 2) the Expert Panel Report on the Reproductive and Developmental Toxicity of Methylphenidate, and 3) public comments received on the Expert Panel Report. As stated in the NTP Brief, the NTP reached the following conclusions regarding the possible effects of exposure to methylphenidate on human development and reproduction. First, there is some concern for developmental effects, specifically for potential neurobehavioral alterations, from prenatal amphetamine exposure in humans both in therapeutic and non-therapeutic settings. After prenatal exposure to therapeutic doses of amphetamine, rat pups demonstrated neurobehavioral alterations. Data from human and animal studies were judged insufficient for an evaluation of the effect of amphetamine exposure on growth and other related developmental effects. Second, there is concern for methamphetamine-induced adverse developmental effects, specifically on growth and neurobehavioral development, in therapeutic and non-therapeutic settings. This conclusion is based

  6. NTP-CERHR Monograph on the Potential Human Reproductive and Developmental Effects of Fluoxetine.

    PubMed

    2004-11-01

    The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) conducted an evaluation of the potential for fluoxetine to cause adverse effects on reproduction and development in humans. Fluoxetine (Prozac(R); Serafemtrade mark) was selected for evaluation because of 1) sufficient reproductive and developmental studies, 2) human exposure information, 3) changing prescription patterns, and 4) public concern about potential reproductive and/or developmental hazards associated with exposure. Fluoxetine, an antidepressant, is also prescribed to treat premenstrual dysphoric disorder and has recently been approved for use in 7-17 year-olds. The results of this evaluation on fluoxetine are published in an NTP-CERHR monograph which includes: 1) the NTP Brief, 2) the Expert Panel Report on the Reproductive and Developmental Toxicity of Fluoxetine, and 3) public comments received on the Expert Panel Report. As stated in the NTP Brief, the NTP reached the following conclusions regarding the possible effects of exposure to fluoxetine on human development and reproduction. First, there is some concern for developmental effects, specifically shortened gestation and poor neonatal adaptation at therapeutic doses (20-80 mg/day). This conclusion is based on evidence from human studies that fluoxetine produces an increased rate of poor neonatal adaptation and that fluoxetine exposure during pregnancy can result in a shortened gestation and reduced birth weight at term. Second, there is minimal concern for adverse reproductive effects in fluoxetine-exposed adults. Evidence from human studies show that therapeutic doses of fluoxetine may, in both men and women, result in reversible, impaired sexual function, specifically a delay in or an inability to achieve orgasm. Finally, there are insufficient data to draw conclusions on 1) an association between fluoxetine therapy in pregnant women and pregnancy loss; and 2) on how breast milk or therapeutic

  7. Subscale Validation of the Subsurface Active Filtration of Exhaust (SAFE) Approach to the NTP Ground Testing

    NASA Technical Reports Server (NTRS)

    Marshall, William M.; Borowski, Stanley K.; Bulman, Mel; Joyner, Russell; Martin, Charles R.

    2015-01-01

    Nuclear thermal propulsion (NTP) has been recognized as an enabling technology for missions to Mars and beyond. However, one of the key challenges of developing a nuclear thermal rocket is conducting verification and development tests on the ground. A number of ground test options are presented, with the Sub-surface Active Filtration of Exhaust (SAFE) method identified as a preferred path forward for the NTP program. The SAFE concept utilizes the natural soil characteristics present at the Nevada National Security Site to provide a natural filter for nuclear rocket exhaust during ground testing. A validation method of the SAFE concept is presented, utilizing a non-nuclear sub-scale hydrogen/oxygen rocket seeded with detectible radioisotopes. Additionally, some alternative ground test concepts, based upon the SAFE concept, are presented. Finally, an overview of the ongoing discussions of developing a ground test campaign are presented.

  8. Design Evolutuion of Hot Isotatic Press Cans for NTP Cermet Fuel Fabrication

    NASA Technical Reports Server (NTRS)

    Mireles, O. R.; Broadway, J.; Hickman, R.

    2014-01-01

    Nuclear Thermal Propulsion (NTP) is under consideration for potential use in deep space exploration missions due to desirable performance properties such as a high specific impulse (> 850 seconds). Tungsten (W)-60vol%UO2 cermet fuel elements are under development, with efforts emphasizing fabrication, performance testing and process optimization to meet NTP service life requirements [1]. Fuel elements incorporate design features that provide redundant protection from crack initiation, crack propagation potentially resulting in hot hydrogen (H2) reduction of UO2 kernels. Fuel erosion and fission product retention barriers include W coated UO2 fuel kernels, W clad internal flow channels and fuel element external W clad resulting in a fully encapsulated fuel element design as shown.

  9. Multidisciplinary Simulation of Graphite-Composite and Cermet Fuel Elements for NTP Point of Departure Designs

    NASA Technical Reports Server (NTRS)

    Stewart, Mark E.; Schnitzler, Bruce G.

    2015-01-01

    This paper compares the expected performance of two Nuclear Thermal Propulsion fuel types. High fidelity, fluid/thermal/structural + neutronic simulations help predict the performance of graphite-composite and cermet fuel types from point of departure engine designs from the Nuclear Thermal Propulsion project. Materials and nuclear reactivity issues are reviewed for each fuel type. Thermal/structural simulations predict thermal stresses in the fuel and thermal expansion mis-match stresses in the coatings. Fluid/thermal/structural/neutronic simulations provide predictions for full fuel elements. Although NTP engines will utilize many existing chemical engine components and technologies, nuclear fuel elements are a less developed engine component and introduce design uncertainty. Consequently, these fuel element simulations provide important insights into NTP engine performance.

  10. A bioaccumulation bioassay for freshwater sediments

    USGS Publications Warehouse

    Mac, Michael J.; Noguchi, George E.; Hesselberg, Robert J.; Edsall, Carol C.; Shoesmith, John A.; Bowker, James D.

    1990-01-01

    A laboratory bioassay is described for determining the bioavailability of contaminants from freshwater sediments. The bioassay consists of 10-d exposures to whole sediments under flow-through conditions. After testing five species, the fathead minnow (Pimephales promelas) and the earthworm (Lubricus terrestris) were recommended for use in the test. When the availability of polychlorinated biphenyls (PCBs), Hg and Zn from Great Lakes sediments was examined in laboratory exposures, only the PCBs were accumulated. A field validation study demonstrated that the magnitude of accumulation in laboratory exposures was similar to that in organisms caged in the field. A protocol is recommended for using the test as a standardized bioaccumulation bioassay.

  11. Characterization of purple acid phosphatases involved in extracellular dNTP utilization in Stylosanthes.

    PubMed

    Liu, Pan-Dao; Xue, Ying-Bin; Chen, Zhi-Jian; Liu, Guo-Dao; Tian, Jiang

    2016-07-01

    Stylo (Stylosanthes spp.) is a pasture legume predominant in tropical and subtropical areas, where low phosphorus (P) availability is a major constraint for plant growth. Therefore, stylo might exhibit superior utilization of the P pool on acid soils, particularly organic P. However, little is known about mechanisms of inorganic phosphate (Pi) acquisition employed by stylo. In this study, the utilization of extracellular deoxy-ribonucleotide triphosphate (dNTP) and the underlying physiological and molecular mechanisms were examined for two stylo genotypes with contrasting P efficiency. Results showed that the P-efficient genotype, TPRC2001-1, was superior to the P-inefficient genotype, Fine-stem, when using dNTP as the sole P source. This was reflected by a higher dry weight and total P content for TPRC2001-1 than for Fine-stem, which was correlated with higher root-associated acid phosphatase (APase) activities in TPRC2001-1 under low P conditions. Subsequently, three PAP members were cloned from TPRC2001-1: SgPAP7, SgPAP10, and SgPAP26 Expression levels of these three SgPAPs were up-regulated by Pi starvation in stylo roots. Furthermore, there was a higher abundance of transcripts of SgPAP7 and SgPAP10 in TPRC2001-1 than in Fine-stem. Subcellular localization analysis demonstrated that these three SgPAPs were localized on the plasma membrane. Overexpression of these three SgPAPs could result in significantly increased root-associated APase activities, and thus extracellular dNTP utilization in bean hairy roots. Taken together, the results herein suggest that SgPAP7, SgPAP10, and SgPAP26 may differentially contribute to root-associated APase activities, and thus control extracellular dNTP utilization in stylo. PMID:27194738

  12. Suppression of the E. coli SOS response by dNTP pool changes.

    PubMed

    Maslowska, Katarzyna H; Makiela-Dzbenska, Karolina; Fijalkowska, Iwona J; Schaaper, Roel M

    2015-04-30

    The Escherichia coli SOS system is a well-established model for the cellular response to DNA damage. Control of SOS depends largely on the RecA protein. When RecA is activated by single-stranded DNA in the presence of a nucleotide triphosphate cofactor, it mediates cleavage of the LexA repressor, leading to expression of the 30(+)-member SOS regulon. RecA activation generally requires the introduction of DNA damage. However, certain recA mutants, like recA730, bypass this requirement and display constitutive SOS expression as well as a spontaneous (SOS) mutator effect. Presently, we investigated the possible interaction between SOS and the cellular deoxynucleoside triphosphate (dNTP) pools. We found that dNTP pool changes caused by deficiencies in the ndk or dcd genes, encoding nucleoside diphosphate kinase and dCTP deaminase, respectively, had a strongly suppressive effect on constitutive SOS expression in recA730 strains. The suppression of the recA730 mutator effect was alleviated in a lexA-deficient background. Overall, the findings suggest a model in which the dNTP alterations in the ndk and dcd strains interfere with the activation of RecA, thereby preventing LexA cleavage and SOS induction. PMID:25824947

  13. Two-generation saccharin bioassays.

    PubMed

    Arnold, D L

    1983-04-01

    The controversy regarding the safety of saccharin for human consumption started shortly after its discovery over 100 years ago and has yet to subside appreciably. The consumption of saccharin, particularly in North America, began to escalate when the U.S. Food and Drug Administration set new standards of identity which allowed foods containing artificial sweeteners to be promoted as "nonnutritive" or "noncaloric" sweeteners for use by the general public. In 1969, when cyclamates were banned, at least 10 single-generation feeding studies were undertaken with saccharin to more accurately assess the potential toxicological consequences resulting from the anticipated increase in its consumption. None of these studies resulted in any overt regulatory action. Subsequently, the introduction of the two-generation chronic toxicity/carcinogenicity bioassay added a new tool to the toxicologist's arsenal. Three two-generation studies using saccharin have since been conducted. The results from these studies clearly show that when rats were exposed to diets containing 5 or 7.5% sodium saccharin from the time of conception to death, an increased frequency of urinary bladder cancers was found, predominantly in the males. While some study results suggested that impurities in commercial saccharin or the presence of urinary tract calculi may have been responsible for the observed bladder tumors, it now appears that these possibilities are highly unlikely. The mechanism by which saccharin elicited the bladder tumors using the two-generation experiment has not been ascertained. PMID:6347682

  14. Bioassays for Monitoring Insecticide Resistance

    PubMed Central

    Miller, Audra L.E.; Tindall, Kelly; Leonard, B. Rogers

    2010-01-01

    Pest resistance to pesticides is an increasing problem because pesticides are an integral part of high-yielding production agriculture. When few products are labeled for an individual pest within a particular crop system, chemical control options are limited. Therefore, the same product(s) are used repeatedly and continual selection pressure is placed on the target pest. There are both financial and environmental costs associated with the development of resistant populations. The cost of pesticide resistance has been estimated at approximately $ 1.5 billion annually in the United States. This paper will describe protocols, currently used to monitor arthropod (specifically insects) populations for the development of resistance. The adult vial test is used to measure the toxicity to contact insecticides and a modification of this test is used for plant-systemic insecticides. In these bioassays, insects are exposed to technical grade insecticide and responses (mortality) recorded at a specific post-exposure interval. The mortality data are subjected to Log Dose probit analysis to generate estimates of a lethal concentration that provides mortality to 50% (LC50) of the target populations and a series of confidence limits (CL's) as estimates of data variability. When these data are collected for a range of insecticide-susceptible populations, the LC50 can be used as baseline data for future monitoring purposes. After populations have been exposed to products, the results can be compared to a previously determined LC50 using the same methodology. PMID:21248689

  15. PHOXOCEPHALID AMPHIPOD BIOASSAY FOR MARINE SEDIMENT TOXICITY

    EPA Science Inventory

    The relative toxicity of marine sediment can be accurately determined through acute, static bioassays with the phoxocepalid amphipod Repoxynius abronius. Mortality and sublethal effects on emergence from sediment and reburial behavior are determined after ten day exposure in 1-L ...

  16. Bioassay criteria for environmental restoration workers

    SciTech Connect

    Carbaugh, E.H.; Bihl, D.E.

    1993-01-01

    Environmental restoration (ER) work at the U. S. Department of Energy Hanford Site posed questions concerning when to perform bioassay monitoring of workers for potential intakes of radioactivity. Application of criteria originally developed for use inside radionuclide processing facilities to ER work resulted in overly restrictive bioassay requirements. ER work typically involves site characterization or, excavating large quantities of potentially contaminated soil, rather than working with concentrated quantities of radioactivity as in a processing facility. An improved approach, tailored to ER work, provided soil contamination concentrations above which worker bioassay would be required. Soil concentrations were derived assuming acute or chronic intakes of 2% of an Annual Limit on Intake (ALI), or a potential committed effective dose equivalent of 100 mrem, and conservative dust loading of air from the work. When planning ER work, the anticipated soil concentration and corresponding need for bioassay could be estimated from work-site historical records. Once site work commenced, soil sampling and work-place surveys could be used to determine bioassay needs. This approach substantially reduced the required number of bioassay samples with corresponding reductions in analytical costs, schedules, and more flexible work-force management. (Work supported by the US Department of Energy under contract DOE-AC06-76RLO 1830.)

  17. A Colorimetric Bioassay for Perchlorate

    NASA Astrophysics Data System (ADS)

    Heinnickel, M. L.; Smith, S.; Coates, J. D.

    2007-12-01

    Recognition of perchlorate (ClO4-) as a widespread contaminant across the United States and its potential adverse affects towards human health has motivated the EPA to place ClO4- on its contaminant candidate list for drinking water supplies. While a federal MCL has not yet been set, a recommended public health goal of 1 ppb (μg.L-1) was established by the US EPA in 2002. To date, methods of detection require use of sensitive ion chromatographic equipment that are expensive, time consuming, and require highly trained personnel for use. Our studies are focused on the development of a highly sensitive, simple, and robust colorimetric bioassay based on the primary enzyme involved in microbial ClO4- reduction, the perchlorate reductase (Pcr). A previously published assay used reduced methyl viologen (MV, the dye is reduced with sodium hydrosulfite) as an electron donor to demonstrate Pcr activity. The assay directly correlates the amount of MV oxidized with the amount of ClO4- reduced by assuming a transfer of four electrons. To test this assumption, we compared actual concentrations of MV oxidized to ClO4- reduced in this assay. ClO4- concentrations were determined using a Dionex ICS-500 ion chromatography system, while MV concentrations were determined using a standard curve generated at 578 nm. Comparisons between the two revealed that twelve molecules of MV were oxidized for each molecule of ClO4- reduced. The oxidation of these additional eight MV molecules is explained by the interaction of the dye with chlorite (the product of the Pcr reaction) and other contaminants that could be present in the enzyme prep. This unsettling result indicated this assay would be problematic for the detection of ClO4- in soil, which has many chemicals that could react with MV. To improve upon this assay, we have tried to reduce ClO4- using less reactive dyes and reductants. The reductants ascorbic acid, NADH, and dithiothreitol drive Pcr catalyzed ClO4- reduction, however, they

  18. Experiences with Non-traditional Bioassay Methods in a Plutonium Processing Line

    SciTech Connect

    La Bone, T.R.

    2003-10-17

    An incident in an Savannah River Site (SRS) plutonium processing line (FB-Line) in 1999 highlighted the fact insoluble forms of plutonium exist at SRS that may not be readily monitored with the routine bioassay programs traditionally used at this site. To address this issue, a study was conducted in FB-Line with 21 participants for a year ending in July 2002. The purpose of the study was to examine the use of three non-traditional monitoring methods and, based on this experience, recommend a routine bioassay program that is capable of monitoring workers potentially exposed to insoluble plutonium. These non-traditional monitoring methods are personal air sampling (PAS), thermal ionization mass spectrometry (TIMS) of urine samples, and routine fecal bioassay. The main conclusions and recommendations of the study are: (1) A routine TIMS urine bioassay program, which is called the enhanced bioassay program (EBP), is recommended for workers in SRS facilities that have a reasonable potential for exposure to insoluble forms of plutonium. (2) Under certain conditions the EBP could result in onerous work restrictions. A contingency plan involving the use of PAS is recommended in this case. PAS is also recommended for workers who have had historic intakes of plutonium that interfere with the detection and interpretation of future intakes of insoluble plutonium. (3) For the EBP to be successful it must be used only for those workers who have a reasonable potential for exposure to insoluble plutonium, and these workers must take all necessary precautions to avoid cross-contamination of the urine (and follow-up fecal) samples. (4) Fecal bioassay is an important tool for follow-up to abnormal events, but routine fecal bioassay is not recommended. (5) The PAS data clearly shows that workers are exposed to low levels of airborne plutonium, but the participants appear to be unlikely to exceed a committed effective dose equivalent of 100 mrem from these exposures.

  19. Low dNTP levels are necessary but may not be sufficient for lentiviral restriction by SAMHD1.

    PubMed

    Welbourn, Sarah; Strebel, Klaus

    2016-01-15

    SAMHD1 is a cellular dNTPase that restricts lentiviral infection presumably by lowering cellular dNTP levels to below a critical threshold required for reverse transcription; however, lowering cellular dNTP levels may not be the sole mechanism of restriction. In particular, an exonuclease activity of SAMHD1 was reported to contribute to virus restriction. We further investigated the requirements for SAMHD1 restriction activity in both differentiated U937 and cycling HeLa cells. Using hydroxyurea treatment to lower baseline dNTP levels in HeLa cells, we were able to document efficient SAMHD1 restriction without significant further reduction in dNTP levels by SAMHD1. These results argue against a requirement for additional myeloid-specific host factors for SAMHD1 function but further support the notion that SAMHD1 possesses an additional dNTP-independent function contributing to lentiviral restriction. However, our own experiments failed to associate this presumed additional SAMHD1 antiviral activity with a reported nuclease activity. PMID:26655245

  20. Tunneling characteristics of Au-alkanedithiol-Au junctions formed via nanotransfer printing (nTP).

    PubMed

    Niskala, Jeremy R; Rice, William C; Bruce, Robert C; Merkel, Timothy J; Tsui, Frank; You, Wei

    2012-07-25

    Construction of permanent metal-molecule-metal (MMM) junctions, though technically challenging, is desirable for both fundamental investigations and applications of molecule-based electronics. In this study, we employed the nanotransfer printing (nTP) technique using perfluoropolyether (PFPE) stamps to print Au thin films onto self-assembled monolayers (SAMs) of alkanedithiol formed on Au thin films. We show that the resulting MMM junctions form permanent and symmetrical tunnel junctions, without the need for an additional protection layer between the top metal electrode and the molecular layer. This type of junction makes it possible for direct investigations into the electrical properties of the molecules and the metal-molecule interfaces. Dependence of transport properties on the length of the alkane molecules and the area of the printed Au electrodes has been examined systematically. From the analysis of the current-voltage (I-V) curves using the Simmons model, the height of tunneling barrier associated with the molecule (alkane) has been determined to be 3.5 ± 0.2 eV, while the analysis yielded an upper bound of 2.4 eV for the counterpart at the interface (thiol). The former is consistent with the theoretical value of ~3.5-5.0 eV. The measured I-V curves show scaling with respect to the printed Au electrode area with lateral dimensions ranging from 80 nm to 7 μm. These results demonstrate that PFPE-assisted nTP is a promising technique for producing potentially scalable and permanent MMM junctions. They also demonstrate that MMM structures (produced by the unique PFPE-assisted nTP) constitute a reliable test bed for exploring molecule-based electronics. PMID:22720785

  1. Affordable Development and Optimization of CERMET Fuels for NTP Ground Testing

    NASA Technical Reports Server (NTRS)

    Hickman, Robert R.; Broadway, Jeramie W.; Mireles, Omar R.

    2014-01-01

    CERMET fuel materials for Nuclear Thermal Propulsion (NTP) are currently being developed at NASA's Marshall Space Flight Center. The work is part of NASA's Advanced Space Exploration Systems Nuclear Cryogenic Propulsion Stage (NCPS) Project. The goal of the FY12-14 project is to address critical NTP technology challenges and programmatic issues to establish confidence in the affordability and viability of an NTP system. A key enabling technology for an NCPS system is the fabrication of a stable high temperature nuclear fuel form. Although much of the technology was demonstrated during previous programs, there are currently no qualified fuel materials or processes. The work at MSFC is focused on developing critical materials and process technologies for manufacturing robust, full-scale CERMET fuels. Prototypical samples are being fabricated and tested in flowing hot hydrogen to understand processing and performance relationships. As part of this initial demonstration task, a final full scale element test will be performed to validate robust designs. The next phase of the project will focus on continued development and optimization of the fuel materials to enable future ground testing. The purpose of this paper is to provide a detailed overview of the CERMET fuel materials development plan. The overall CERMET fuel development path is shown in Figure 2. The activities begin prior to ATP for a ground reactor or engine system test and include materials and process optimization, hot hydrogen screening, material property testing, and irradiation testing. The goal of the development is to increase the maturity of the fuel form and reduce risk. One of the main accomplishmens of the current AES FY12-14 project was to develop dedicated laboratories at MSFC for the fabrication and testing of full length fuel elements. This capability will enable affordable, near term development and optimization of the CERMET fuels for future ground testing. Figure 2 provides a timeline of the

  2. Susceptibility of Bagrada hilaris (Hemiptera: Pentatomidae) to Insecticides in Laboratory and Greenhouse Bioassays.

    PubMed

    Palumbo, John C; Prabhaker, Nilima; Reed, Darcy A; Perring, Thomas M; Castle, Steven J; Huang, Ta-I

    2015-04-01

    Field-collected nymphs and adults of Bagrada hilaris (Burmeister) (Hemiptera: Penatatomidae) from three locations were evaluated for susceptibility to insecticides representing 10 classes of insecticide chemistry. Although relative susceptibilities differed between leaf-spray and leaf-dip Petri dish bioassays, consistently low LC50 values were determined for chlorpyrifos, bifenthrin, and lambda-cyhalothrin. Fenpropathrin and methomyl had intermediate values. Susceptibility to dinotefuran varied depending on the bioassay, possibly owing to leaf substrates used in the two bioassays. In soil systemic bioassays, the LC50 value of dinotefuran was significantly greater than that of two other neonicotinoids, imidacloprid and thiamethoxam, and the anthranilic diamide, cyantraniliprole. Mortality and feeding damage of B. hilaris and plant growth on insecticide-treated plants in greenhouse trials were consistent with the laboratory bioassays; the best results were seen with bifenthrin, methomyl, and chlorpyrifos. Mortality to the neonicotinoids was not evident; however, feeding damage and plant growth responses on dinotefuran-treated plants damage were similar to the noninfested control. This highlights the apparent antifeedant properties of dinotefuran that may have prevented adults from injuring broccoli plants after exposure to foliar spray residues. Data presented serve as baseline susceptibilities that can be used to monitor for resistance development in field populations of B. hilaris. PMID:26470178

  3. Effects of metals in in vitro bioassays.

    PubMed Central

    Sirover, M A

    1981-01-01

    The capacity of in vitro bioassays to detect the potential carcinogenicity of metal compounds is reviewed. The in vitro bioassays discussed include: bacterial reversion analysis to determine the capacity of metal salts to revert Salmonella typhimurium histidine auxotrophs or to revert Escherichia coli WP 2 tryp- to tryptophan prototrophy; examination of the ability of metal salts to preferentially inhibit cell growth in Bacillus subtilis cells deficient in DNA repair pathways; determination of the ability of metal salts to induce resistance to base analogs in mammalian cells; the capacity of metal salts to enhance viral transformation of mammalian cells or to transform cells in the absence of virus; and the ability of metal salts to induce chromosomal aberrations in mammalian cells. Using each of these in vitro bioassays, diverse metal compounds have been identified as potential carcinogens. Furthermore, the use of different compounds of a specific metal may allow a determination of the valence which may be required for carcinogenesis. PMID:7023930

  4. Poultry litter toxicity comparison from various bioassays

    SciTech Connect

    Gupta, G.; Kelly, P. )

    1992-01-01

    Poultry litter contains many toxic chemicals including Cu, As, Pb, Cd, Hg, Se and PCBs. Poultry litter leachate has been shown to be more toxic to marine luminescent organisms (Photobacterium phosphoreum) than other farm animal manures. A comparison of toxicity of the poultry litter leachate was undertaken using various bioassays. The EC{sub 50} (or LC{sub 50}) value for the leachate with the Microtox and Daphnia bioassays was 2.9 g/L/ Nitrobacter and Pseudomonas bioassays were not useful in determining the leachate toxicity because of the nutritional properties of the litter. Poultry litter leachate was found to be mutagenic to strains TA 97, TA 98, TA 100 and TA 102 using the Ames Test.

  5. RECOMMENDATIONS FOR UO3 PLANT BIOASSAY

    SciTech Connect

    Carbaugh, Eugene H.

    2010-07-12

    Alternative urine bioassay programs are described for application with decontamination and decommissioning activities at the Hanford UO3 Plant. The alternatives are based on quarterly or monthly urine bioassay for recycled uranium, assuming multiple acute inhalation intakes of recycled uranium occurring over a year. The inhalations are assumed to be 5µm AMAD particles of 80% absorption type F and 20% absorption type M. Screening levels, expressed as daily uranium mass excretion rates in urine, and the actions associated with these levels are provided for both quarterly and monthly sampling frequencies.

  6. NTP CENTER FOR THE EVALUATION OF RISKS TO HUMAN REPRODUCTION: PHTHALATES EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF DI(2-ETHYLHEXYL) PHTHALATE

    EPA Science Inventory

    Kavlock et al.; "NTP Center for the Evaluation....

    Abstract

    The phthalates are a family of environmentally important compounds with diverse uses. Reproductive toxicity has been demonstrated for some members of this family. The NTP Center for the Evaluation of Risk...

  7. NTP CENTER FOR THE EVALUATION OF RISKS TO HUMAN REPRODUCTION: PHTHALATES EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF DI-ISONONYL PHTHALATE

    EPA Science Inventory

    Kavlock et al.; "NTP Center for the Evaluation....

    Abstract

    The phthalates are a family of environmentally important compounds with diverse uses. Reproductive toxicity has been demonstrated for some members of this family. The NTP Center for the Evaluation of Risk...

  8. NTP CENTER FOR THE EVALUATION OF RISKS TO HUMAN REPRODUCTION: PHTHALATES EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF DI-ISODECYL PHTHALATE

    EPA Science Inventory

    Kavlock et al.; "NTP Center for the Evaluation....

    Abstract

    The phthalates are a family of environmentally important compounds with diverse uses. Reproductive toxicity has been demonstrated for some members of this family. The NTP Center for the Evaluation of Risk...

  9. NTP CENTER FOR THE EVALUATION OF RISKS TO HUMAN REPRODUCTION: PHTHALATES EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF DI-N-OCTYL PHTHALATE

    EPA Science Inventory

    Kavlock et al.; "NTP Center for the Evaluation....

    Abstract

    The phthalates are a family of environmentally important compounds with diverse uses. Reproductive toxicity has been demonstrated for some members of this family. The NTP Center for the Evaluation of Risk...

  10. NTP-CERHR expert panel report on the reproductive anddevelopmental toxicity of hydroxyurea

    SciTech Connect

    Liebelt, E.L.; Balk, S.J.; Faber, W.; Fisher, J.W.; Hughes, C.L.; Lanzkron, S.M.; Lewis, K.M.; Marchetti, F.; Mehendale, H.M.; Rogers,J.M.; Shad, A.T.; Skalko, R.G.; Stanek, E.J.

    2007-01-01

    The National Toxicology Program (NTP) and the National Institute of Environmental Health Sciences (NIEHS) established the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR) in June 1998. The purpose of CERHR is to provide timely, unbiased, scientifically sound evaluations of human and experimental evidence for adverse effects on reproduction and development caused by agents to which humans may be exposed. Hydroxyurea was selected for evaluation by a CERHR expert panel because of (1) its increasing use in the treatment of sickle cell disease in children and adults, (2) knowledge that it inhibits DNA synthesis and is cytotoxic, and (3) published evidence of its reproductive and developmental toxicity in rodents. Hydroxyurea is FDA-approved for reducing the frequency of painful crises and the need for blood transfusions in adults with sickle cell anemia who experience recurrent moderate-to-severe crises. Hydroxyurea is used in the treatment of cancer, sickle cell disease, and thalassemia. It is the only treatment for sickle cell disease aside from blood transfusion used in children. Hydroxyurea may be used in the treatment of children and adults with sickle cell disease for an extended period of time or for repeated cycles of therapy. Treatment with hydroxyurea may be associated with cytotoxic and myelosuppressive effects, and hydroxyurea is mutagenic.

  11. BIOASSAY-DIRECTED CHEMICAL ANALYSIS IN ENVIRONMENTAL RESEARCH

    EPA Science Inventory

    The use of short-term bioassay tests in conjunction with analytical measurements, constitute a powerful tool for identifying important environmental contaminants. The authors have coined the terminology 'bioassay directed chemical analysis' to best describe this marriage of analy...

  12. Micro-organism distribution sampling for bioassays

    NASA Technical Reports Server (NTRS)

    Nelson, B. A.

    1975-01-01

    Purpose of sampling distribution is to characterize sample-to-sample variation so statistical tests may be applied, to estimate error due to sampling (confidence limits) and to evaluate observed differences between samples. Distribution could be used for bioassays taken in hospitals, breweries, food-processing plants, and pharmaceutical plants.

  13. EDC BIOASSAYS FOR RISK MANAGEMENT PROJECTS

    EPA Science Inventory

    Overall goal for this research is to develop 3 bioassays for use in EDC projects across NRMRL (estrogenic, androgenic and thyroid assays). Currently, research is focused on estrogenic assays. A literature search was conducted to identify potential assays. The Yeast Estrogen Sc...

  14. Brine Shrimp Bioassays: A Useful Technique in Biological Investigations

    ERIC Educational Resources Information Center

    Rice, Stanley A.; Maness, Ian B.

    2004-01-01

    A technique to measure the potency of leaf compounds against herbivores with the use of a bioassay is described. Bioassays are useful in classes where students have career plans like medicine in which bioassays can be used as tools for screening plants for possible medicinal potency.

  15. BIOASSAY-DIRECTED FRACTIONATION OF ORGANIC CONTAMINANTS IN AN ESTUARINE SEDIMENT USING THE NEW MUTAGENIC BIOASSAY, MUTATOX

    EPA Science Inventory

    Bioassay-directed fractionation of organic compounds was performed on an organic solvent extract of a contaminated estuarine sediment from Black Rock Harbor, Connecticut, using the new mutagenic bioassay, Mutatox-. hemical fractionation methods of the sediment extract included si...

  16. Research Highlights, 2003

    ERIC Educational Resources Information Center

    ACER Press (Australian Council for Educational Research), 2003

    2003-01-01

    "Research Highlights" is an annual publication documenting developments in the Australian Council for Educational Research's (ACER's) research programs for the previous year. The 2003 edition highlights research on the following themes: (1) Australian students excel in international study; (2) Assessing the moral and ethical outcomes of schooling;…

  17. APPA 2011 Conference Highlights

    ERIC Educational Resources Information Center

    Facilities Manager, 2011

    2011-01-01

    This article presents highlights of APPA conference that was held on July 16-18, 2011. The highlights feature photos of 2011-2012 board of directors, outgoing senior regional representatives to the board, meritorious service award, APPA fellow, president's recognition and gavel exchange, and diamond business partner award.

  18. Highlights of 1978 activities

    NASA Technical Reports Server (NTRS)

    1978-01-01

    General highlights of NASA's activities for 1978 are presented. The highlights are categorized into topics such as space science, space transportation systems, space and terrestrial applications, environment, technology utilization, aeronautics, space research and technology, energy programs, and international. A list of the 1978 launches including: (1) launch date; (2) payload designation; (3) launch vehicle; (4) launch site and (5) mission remarks is also presented.

  19. In vitro bioassays to evaluate complex chemical mixtures in recycled water

    PubMed Central

    Jia, Ai; Escher, Beate I.; Leusch, Frederic D.L.; Tang, Janet Y.M.; Prochazka, Erik; Dong, Bingfeng; Snyder, Erin M.; Snyder, Shane A.

    2016-01-01

    With burgeoning population and diminishing availability of freshwater resources, the world continues to expand the use of alternative water resources for drinking, and the quality of these sources has been a great concern for the public as well as public health professionals. In vitro bioassays are increasingly being used to enable rapid, relatively inexpensive toxicity screening that can be used in conjunction with analytical chemistry data to evaluate water quality and the effectiveness of water treatment. In this study, a comprehensive bioassay battery consisting of 36 bioassays covering 18 biological endpoints was applied to screen the bioactivity of waters of varying qualities with parallel treatments. Samples include wastewater effluent, ultraviolet light (UV) and/or ozone advanced oxidation processed (AOP) recycled water, and infiltrated recycled groundwater. Based on assay sensitivity and detection frequency in the samples, several endpoints were highlighted in the battery, including assays for genotoxicity, mutagenicity, estrogenic activity, glucocorticoid activity, aryl hydrocarbon receptor activity, oxidative stress response, and cytotoxicity. Attenuation of bioactivity was found to be dependent on the treatment process and bioassay endpoint. For instance, ozone technology significantly removed oxidative stress activity, while UV based technologies were most efficient for the attenuation of glucocorticoid activity. Chlorination partially attenuated genotoxicity and greatly decreased herbicidal activity, while groundwater infiltration efficiently attenuated most of the evaluated bioactivity with the exception of genotoxicity. In some cases, bioactivity (e.g., mutagenicity, genotoxicity, and arylhydrocarbon receptor) increased following water treatment, indicating that transformation products of water treatment may be a concern. Furthermore, several types of bioassays with the same endpoint were compared in this study, which could help guide the selection

  20. In vitro bioassays to evaluate complex chemical mixtures in recycled water.

    PubMed

    Jia, Ai; Escher, Beate I; Leusch, Frederic D L; Tang, Janet Y M; Prochazka, Erik; Dong, Bingfeng; Snyder, Erin M; Snyder, Shane A

    2015-09-01

    With burgeoning population and diminishing availability of freshwater resources, the world continues to expand the use of alternative water resources for drinking, and the quality of these sources has been a great concern for the public as well as public health professionals. In vitro bioassays are increasingly being used to enable rapid, relatively inexpensive toxicity screening that can be used in conjunction with analytical chemistry data to evaluate water quality and the effectiveness of water treatment. In this study, a comprehensive bioassay battery consisting of 36 bioassays covering 18 biological endpoints was applied to screen the bioactivity of waters of varying qualities with parallel treatments. Samples include wastewater effluent, ultraviolet light (UV) and/or ozone advanced oxidation processed (AOP) recycled water, and infiltrated recycled groundwater. Based on assay sensitivity and detection frequency in the samples, several endpoints were highlighted in the battery, including assays for genotoxicity, mutagenicity, estrogenic activity, glucocorticoid activity, arylhydrocarbon receptor activity, oxidative stress response, and cytotoxicity. Attenuation of bioactivity was found to be dependent on the treatment process and bioassay endpoint. For instance, ozone technology significantly removed oxidative stress activity, while UV based technologies were most efficient for the attenuation of glucocorticoid activity. Chlorination partially attenuated genotoxicity and greatly decreased herbicidal activity, while groundwater infiltration efficiently attenuated most of the evaluated bioactivity with the exception of genotoxicity. In some cases, bioactivity (e.g., mutagenicity, genotoxicity, and arylhydrocarbon receptor) increased following water treatment, indicating that transformation products of water treatment may be a concern. Furthermore, several types of bioassays with the same endpoint were compared in this study, which could help guide the selection

  1. Mismatched dNTP incorporation by DNA polymerase [beta] does not proceed via globally different conformational pathways

    SciTech Connect

    Tang, Kuo-Hsiang; Niebuhr, Marc; Tung, Chang-Shung; Chan, Hsiu-chien; Chou, Chia-Cheng; Tsai, Ming-Daw

    2008-07-07

    Understanding how DNA polymerases control fidelity requires elucidation of the mechanisms of matched and mismatched dNTP incorporations. Little is known about the latter because mismatched complexes do not crystallize readily. In this report, we employed small-angle X-ray scattering (SAXS) and structural modeling to probe the conformations of different intermediate states of mammalian DNA polymerase {beta} (Pol {beta}) in its wild-type and an error-prone variant, I260Q. Our structural results indicate that the mismatched ternary complex lies in-between the open and the closed forms, but more closely resembles the open form for WT and the closed form for I260Q. On the basis of molecular modeling, this over-stabilization of mismatched ternary complex of I260Q is likely caused by formation of a hydrogen bonding network between the side chains of Gln{sup 260}, Tyr{sup 296}, Glu{sup 295} and Arg{sup 258}, freeing up Asp{sup 192} to coordinate MgdNTP. These results argue against recent reports suggesting that mismatched dNTP incorporations follow a conformational path distinctly different from that of matched dNTP incorporation, or that its conformational closing is a major contributor to fidelity.

  2. Genetic evidence that both dNTP-stabilized and strand slippage mechanisms may dictate DNA polymerase errors within mononucleotide microsatellites.

    PubMed

    Baptiste, Beverly A; Jacob, Kimberly D; Eckert, Kristin A

    2015-05-01

    Mononucleotide microsatellites are tandem repeats of a single base pair, abundant within coding exons and frequent sites of mutation in the human genome. Because the repeated unit is one base pair, multiple mechanisms of insertion/deletion (indel) mutagenesis are possible, including strand-slippage, dNTP-stabilized, and misincorportion-misalignment. Here, we examine the effects of polymerase identity (mammalian Pols α, β, κ, and η), template sequence, dNTP pool size, and reaction temperature on indel errors during in vitro synthesis of mononucleotide microsatellites. We utilized the ratio of insertion to deletion errors as a genetic indicator of mechanism. Strikingly, we observed a statistically significant bias toward deletion errors within mononucleotide repeats for the majority of the 28 DNA template and polymerase combinations examined, with notable exceptions based on sequence and polymerase identity. Using mutator forms of Pol β did not substantially alter the error specificity, suggesting that mispairing-misalignment mechanism is not a primary mechanism. Based on our results for mammalian DNA polymerases representing three structurally distinct families, we suggest that dNTP-stabilized mutagenesis may be an alternative mechanism for mononucleotide microsatellite indel mutation. The change from a predominantly dNTP-stabilized mechanism to a strand-slippage mechanism with increasing microsatellite length may account for the differential rates of tandem repeat mutation that are observed genome-wide. PMID:25758780

  3. Genetic Evidence That Both dNTP-Stabilized and Strand Slippage Mechanisms May Dictate DNA Polymerase Errors Within Mononucleotide Microsatellites

    PubMed Central

    Baptiste, Beverly A.; Jacob, Kimberly D.; Eckert, Kristin A.

    2015-01-01

    Mononucleotide microsatellites are tandem repeats of a single base pair, abundant within coding exons and frequent sites of mutation in the human genome. Because the repeated unit is one base pair, multiple mechanisms of insertion/deletion (indel) mutagenesis are possible, including strand-slippage, dNTP-stabilized, and misincorportion-misalignment. Here, we examine the effects of polymerase identity (mammalian Pols α, β, κ, and η), template sequence, dNTP pool size, and reaction temperature on indel errors during in vitro synthesis of mononucleotide microsatellites. We utilized the ratio of insertion to deletion errors as a genetic indicator of mechanism. Strikingly, we observed a statistically significant bias towards deletion errors within mononucleotide repeats for the majority of the 28 DNA template and polymerase combinations examined, with notable exceptions based on sequence and polymerase identity. Using mutator forms of Pol β did not substantially alter the error specificity, suggesting that mispairing-misalignment mechanism is not a primary mechanism. Based on our results for mammalian DNA polymerases representing three structurally distinct families, we suggest that dNTP-stabilized mutagenesis may be an alternative mechanism for mononucleotide microsatellite indel mutation. The change from a predominantly dNTP-stabilized mechanism to a strand-slippage mechanism with increasing microsatellite length may account for the differential rates of tandem repeat mutation that are observed genome-wide. PMID:25758780

  4. Cyclin D3-dependent control of the dNTP pool and HIV-1 replication in human macrophages.

    PubMed

    Ruiz, Alba; Pauls, Eduardo; Badia, Roger; Torres-Torronteras, Javier; Riveira-Muñoz, Eva; Clotet, Bonaventura; Martí, Ramon; Ballana, Ester; Esté, José A

    2015-01-01

    Cyclins control the activation of cyclin-dependent kinases (CDK), which in turn, control the cell cycle and cell division. Intracellular availability of deoxynucleotides (dNTP) plays a fundamental role in cell cycle progression. SAM domain and HD domain-containing protein 1 (SAMHD1) degrades nucleotide triphosphates and controls the size of the dNTP pool. SAMHD1 activity appears to be controlled by CDK. Here, we show that knockdown of cyclin D3 a partner of CDK6 and E2 a partner of CDK2 had a major impact in SAMHD1 phosphorylation and inactivation and led to decreased dNTP levels and inhibition of HIV-1 at the reverse transcription step in primary human macrophages. The effect of cyclin D3 RNA interference was lost after degradation of SAMHD1 by HIV-2 Vpx, demonstrating the specificity of the mechanism. Cyclin D3 inhibition correlated with decreased activation of CDK2. Our results confirm the fundamental role of the CDK6-cyclin D3 pair in controlling CDK2-dependent SAMHD1 phosphorylation and dNTP pool in primary macrophages. PMID:25927932

  5. Highlights from Fermilab

    NASA Astrophysics Data System (ADS)

    Oddone, P. J.

    2010-12-01

    DISCUSSION by CHAIRMAN: P.J. ODDONE, Scientific Secretaries: W. Fisher, A. Holzner Note from Publisher: The Slides of the Lecture: "Highlights from Fermilab" can be found at http://www.ccsem.infn.it/issp2007/

  6. Langley test highlights, 1981

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Significant aircraft tests which were performed are highlighted. The broad range of the research and technology activities. The conributions of this work toward maintaining United States leadership in aeronautics and space research are illustrated.

  7. Highlights from Fermilab

    SciTech Connect

    Parke, Stephen J.; /Fermilab

    2009-12-01

    In these two lectures I will chose some highlights from the Tevatron experiments (CDF/D0) and the Neutrino experiments and then discuss the future direction of physics at Fermilab after the Tevatron collider era.

  8. NSI organization and highlights

    NASA Technical Reports Server (NTRS)

    Rounds, Fred

    1991-01-01

    The agenda of the NASA Science Internet (NSI) Users Working Group is given. The NSI project organization is laid out in view graph format. Also given are NSI highlights which are divided into three areas: administration, engineering, and operations.

  9. The impact of molecular manipulation in residue 114 of Human Immunodeficiency Virus Type-1 reverse transcriptase on dNTP substrate binding and viral replication

    PubMed Central

    Van Cor-Hosmer, Sarah K.; Daddacha, Waaqo; Kelly, Z; Tsurumi, Amy; Kennedy, Edward M.; Kim, Baek

    2013-01-01

    Human immunodeficiency virus type-1 (HIV-1) reverse transcriptase (RT) has a unique tight binding to dNTP substrates. Structural modeling of Ala-114 of HIV-1 RT suggests that longer side chains at this residue can reduce the space normally occupied by the sugar moiety of an incoming dNTP. Indeed, mutations at Ala-114 decrease the ability of RT to synthesize DNA at low dNTP concentrations and reduce the dNTP-binding affinity (Kd) of RT. However, the Kd values of WT and A114C RT remained equivalent with an acylic dNTP substrate. Finally, mutant A114 RT HIV-1 vectors displayed a greatly reduced transduction in nondividing human lung fibroblasts (HLFs), while WT HIV-1 vector efficiently transduced both dividing and nondividing HLFs. Together these data support that the A114 residue of HIV-1 RT plays a key mechanistic role in the dNTP binding of HIV-1 RT and the unique viral infectivity of target cell types with low dNTP pools. PMID:22153297

  10. Combination of NTP with cetuximab inhibited invasion/migration of cetuximab-resistant OSCC cells: Involvement of NF-κB signaling.

    PubMed

    Chang, Jae Won; Kang, Sung Un; Shin, Yoo Seob; Seo, Seong Jin; Kim, Yeon Soo; Yang, Sang Sik; Lee, Jong-Soo; Moon, Eunpyo; Lee, Keunho; Kim, Chul-Ho

    2015-01-01

    Although the epidermal growth factor receptor (EGFR) is an established target in head-and-neck cancer (HNC), resistance to EGFR-targeted therapy mediated by various mechanisms has been reported. Therefore, a combination strategy to overcome resistance to EGFR mono-targeted therapy is clinically required. We have previously demonstrated that non-thermal atmospheric pressure plasma (NTP) induces death of various cancer cells, including oral squamous cancer (OSCC) cells. In this study, we report for the first time that combining NTP treatment with cetuximab led to inhibition of migration and invasion in cetuximab-resistant OSCC cells, which could be a promising strategy to overcome resistance to anti-EGFR therapy. NTP induced deactivation of NF-κB in SCCQLL1 cells, but not in MSKQLL1 cells. In addition, NTP increased the expression level of E-cadherin, and decreased those of vimentin, Slug, Snail, matrix metalloproteinase (MMP)-2, -9, and activities of MMPs. Moreover, NF-κB upregulation using cDNA diminished the combination effect of NTP on invasion, migration and related signals. Taken together, these results indicate that the combination of NTP with cetuximab can decrease invasiveness in cetuximab-resistant OSCCs through a novel mechanism involving the NF-κB pathway. These findings show the therapeutic potential of treatment that combines NTP and cetuximab in OSCC. PMID:26655729

  11. Combination of NTP with cetuximab inhibited invasion/migration of cetuximab-resistant OSCC cells: Involvement of NF-κB signaling

    PubMed Central

    Chang, Jae Won; Kang, Sung Un; Shin, Yoo Seob; Seo, Seong Jin; Kim, Yeon Soo; Yang, Sang Sik; Lee, Jong-Soo; Moon, Eunpyo; Lee, Keunho; Kim, Chul-Ho

    2015-01-01

    Although the epidermal growth factor receptor (EGFR) is an established target in head-and-neck cancer (HNC), resistance to EGFR-targeted therapy mediated by various mechanisms has been reported. Therefore, a combination strategy to overcome resistance to EGFR mono-targeted therapy is clinically required. We have previously demonstrated that non-thermal atmospheric pressure plasma (NTP) induces death of various cancer cells, including oral squamous cancer (OSCC) cells. In this study, we report for the first time that combining NTP treatment with cetuximab led to inhibition of migration and invasion in cetuximab-resistant OSCC cells, which could be a promising strategy to overcome resistance to anti-EGFR therapy. NTP induced deactivation of NF-κB in SCCQLL1 cells, but not in MSKQLL1 cells. In addition, NTP increased the expression level of E-cadherin, and decreased those of vimentin, Slug, Snail, matrix metalloproteinase (MMP)-2, -9, and activities of MMPs. Moreover, NF-κB upregulation using cDNA diminished the combination effect of NTP on invasion, migration and related signals. Taken together, these results indicate that the combination of NTP with cetuximab can decrease invasiveness in cetuximab-resistant OSCCs through a novel mechanism involving the NF-κB pathway. These findings show the therapeutic potential of treatment that combines NTP and cetuximab in OSCC. PMID:26655729

  12. A Comparison of Materials Issues for Cermet and Graphite-Based NTP Fuels

    NASA Technical Reports Server (NTRS)

    Stewart, Mark E.; Schnitzler, Bruce G.

    2013-01-01

    This paper compares material issues for cermet and graphite fuel elements. In particular, two issues in NTP fuel element performance are considered here: ductile to brittle transition in relation to crack propagation, and orificing individual coolant channels in fuel elements. Their relevance to fuel element performance is supported by considering material properties, experimental data, and results from multidisciplinary fluid/thermal/structural simulations. Ductile to brittle transition results in a fuel element region prone to brittle fracture under stress, while outside this region, stresses lead to deformation and resilience under stress. Poor coolant distribution between fuel element channels can increase stresses in certain channels. NERVA fuel element experimental results are consistent with this interpretation. An understanding of these mechanisms will help interpret fuel element testing results.

  13. Controlador para un Reloj GPS de Referencia en el Protocolo NTP

    NASA Astrophysics Data System (ADS)

    Hauscarriaga, F.; Bareilles, F. A.

    The synchronization between computers in a local network plays a very important role on enviroments similar to IAR. Calculations for exact time are needed before, during and after an observation. For this purpose the IAR's GNU/Linux Software Development Team implemented a driver inside NTP protocol (an internet standard for time synchronization of computers) for a GPS receiver acquired a few years ago by IAR, which did not have support in such protocol. Today our Institute has a stable and reliable time base synchronized to atomic clocks on board GPS Satellites according to computers's synchronization standard, offering precise time services to all scientific community and particularly to the University of La Plata. FULL TEXT IN SPANISH

  14. Bioassaying for ozone with pollen systems

    SciTech Connect

    Feder, W.A.

    1981-01-01

    Sensitivity to ozone of pollen germinating in vitro is closely correlated with ozone sensitivity of the pollen parent. Ozone-sensitive and tolerant pollen populations have been identified in tobacco, petunia, and tomato cultivars. The rate of tube elongation can be reversibly slowed or stopped by exposure to low concentrations of ozone. The performance of selected pollen populations can then be used to bioassay ozone in ambient air by introducing the air sample into a growth chamber where ozone-sensitive pollen in growing. Year-round pollen producion can be achieved in the greenhouse. Harvested pollen can be tested, packaged, and transported to user facilities without loss of vigor. Pollen populations are inexpensive to produce, respond reliably, and are simple to use as a bioassay for air quality.

  15. Bioassay Labels Based on Apoferritin Nanovehicles

    SciTech Connect

    Liu, Guodong; Wang, Jun; Lea, Alan S.; Lin, Yuehe

    2006-09-04

    Here we report a nanoparticle label based on apoferritin nanovehicle loaded internally with markers for sensitive electrochemical DNA detection. The central cavity structure, the dissociation and reconstitute properties at different pHs of apoferritin provide a facile method to load and release markers. Hexacynoferrate(III) was used as model marker to load into the cavity of apoferritin protein cage. The loaded nanoparticle surface was functionalized with amino-modified DNA probe. Electrochemical DNA hybridization assay based on the hexacynoferrate loaded apoferritin nanovehicle could detect 23 atmol DNA targets in 50 ul sample solution. The concept could be readily extended to load other redox and fluorescence markers for bioassay applications. The new nanoparticle labels hold great promise for multi-target detection (in connection to nanoparticles loaded with different markers) and for enhancing the sensitivity of other bioassays.

  16. Disruption of the mevalonate pathway induces dNTP depletion and DNA damage.

    PubMed

    Martín Sánchez, Covadonga; Pérez Martín, José Manuel; Jin, Jong-Sik; Dávalos, Alberto; Zhang, Wei; de la Peña, Gema; Martínez-Botas, Javier; Rodríguez-Acebes, Sara; Suárez, Yajaira; Hazen, María José; Gómez-Coronado, Diego; Busto, Rebeca; Cheng, Yung-Chi; Lasunción, Miguel A

    2015-09-01

    The mevalonate pathway is tightly linked to cell division. Mevalonate derived non-sterol isoprenoids and cholesterol are essential for cell cycle progression and mitosis completion respectively. In the present work, we studied the effects of fluoromevalonate, a competitive inhibitor of mevalonate diphosphate decarboxylase, on cell proliferation and cell cycle progression in both HL-60 and MOLT-4 cells. This enzyme catalyzes the synthesis of isopentenyl diphosphate, the first isoprenoid in the cholesterol biosynthesis pathway, consuming ATP at the same time. Inhibition of mevalonate diphosphate decarboxylase was followed by a rapid accumulation of mevalonate diphosphate and the reduction of ATP concentrations, while the cell content of cholesterol was barely affected. Strikingly, mevalonate diphosphate decarboxylase inhibition also resulted in the depletion of dNTP pools, which has never been reported before. These effects were accompanied by inhibition of cell proliferation and cell cycle arrest at S phase, together with the appearance of γ-H2AX foci and Chk1 activation. Inhibition of Chk1 in cells treated with fluoromevalonate resulted in premature entry into mitosis and massive cell death, indicating that the inhibition of mevalonate diphosphate decarboxylase triggered a DNA damage response. Notably, the supply of exogenously deoxyribonucleosides abolished γ-H2AX formation and prevented the effects of mevalonate diphosphate decarboxylase inhibition on DNA replication and cell growth. The results indicate that dNTP pool depletion caused by mevalonate diphosphate decarboxylase inhibition hampered DNA replication with subsequent DNA damage, which may have important consequences for replication stress and genomic instability. PMID:26055626

  17. Perspectives in avoidance-preference bioassays

    SciTech Connect

    Steele, C.W.; Taylor, D.H.; Strickler-Shaw, S.

    1996-12-31

    Although behavioral endpoints are used in hazard assessment, establishment of water quality criteria and assessment of a contaminant`s hazard to aquatic life rely primarily on standard acute and chronic toxicity tests. Sublethal effects of pollutants should, however, be of major concern because more organisms experience sublethal rather than acutely or chronically lethal exposures of contaminants. The avoidance-preference approach to behavioral bioassays is very useful in screening pollutants for which the mechanisms of perception or response are largely unknown. The underlying philosophy of these studies is that an animal which perceives a chemical can be attracted or repulsed by it. No response is frequently assumed to indicate lack of perception. All three responses have broad ecological implications. The authors discuss the conditions required for performing avoidance-preference bioassays, as well as their sensitivities, advantages, and limitations. In this regard, a comparative approach is used in examining the results of avoidance-preference bioassays with zebrafish in two different apparatuses. Finally, they compare the results of avoidance-preference studies with other measures of the behavioral toxicity of lead to tadpoles.

  18. NASA Langley Highlights, 1997

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Langley's mission is accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government Agencies, industry, other NASA Centers, the educational community, and the local community. This report contains highlights of some of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate the broad range of research and technology activities carried out by NASA Langley Research Center and the contributions of this work toward maintaining United States' leadership in aeronautics and space research.

  19. E News: Report highlights

    SciTech Connect

    1995-01-01

    Three technologies are highlighted in this issue: a rooftop ice storage system for small commercial loads; chlorofluorocarbon-free electric chillers and their expected market; and the FlashBake oven, a commercial-sized oven that uses high intensity quartz lamps to cook food quickly. Regular columns on Member News and Work in Progress are included.

  20. Recent Highlights from VERITAS

    NASA Astrophysics Data System (ADS)

    Wakely, Scott

    VERITAS, an array of atmospheric Cherenkov TeV gamma-ray telescopes, has been in opera-tion since 2007. We will present some highlights from the first few years of observations, with an emphasis on those results most relevant to galactic cosmic-ray astrophysics.

  1. Highlights of 1976 activities

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, M.

    1976-01-01

    Highlights of NASA's 1976 activities are summarized. Sixteen successful launches were made. Two landings of Viking spacecraft on Mars and rollout of the space shuttle orbiter are reviewed. Applications of aerospace science to education, health care, and community services are also discussed.

  2. NASA highlights, 1986 - 1988

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Highlights of NASA research from 1986 to 1988 are discussed. Topics covered include Space Shuttle flights, understanding the Universe and its origins, understanding the Earth and its environment, air and space transportation, using space to make America more competitive, using space technology an Earth, strengthening America's education in science and technology, the space station, and human exploration of the solar system.

  3. Highlights of 1981 activities

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The highlights of NASA's 1981 activities are presented, including the results of the two flights of the space shuttle Columbia and the Voyager 2 encounter with Saturn. Accomplishments in the areas of space transportation operations; space science; aeronautical, energy, and space research and development; as well as space tracking, international activities, and 1981 launch activities are discussed.

  4. Collegiate Athletics Highlights.

    ERIC Educational Resources Information Center

    St. John, Eric

    1999-01-01

    Highlights 15 trends/events in black college athletics, including championship coaches, Black Coaches Association, eligibility issues, disclosure of athlete graduation rates, athletics resource allocation, early adoption of professional athlete status, success of the Women's National Basketball Association, lack of black access to certain sports,…

  5. NASA Langley Highlights, 1998

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Langley's mission is accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government Agencies, industry, other NASA Centers, the educational community, and the local community. This report contains highlights of some of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate the broad range of research and technology activities carried out by NASA Langley Research Center and the contributions of this work toward maintaining United States' leadership in aeronautics and space research. A color electronic version of this report is available at URL http://larcpubs.larc.nasa.gov/randt/1998/.

  6. 1999 Digital Avionics Highlights

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.

    1999-01-01

    This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA Centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, and similar sources.

  7. In-situ bioassays using caged bivalves

    SciTech Connect

    Salazar, M.H.; Salazar, S.M.

    1995-12-31

    It is important to make the distinction between chemical measurements to assess bioaccumulation potential versus biological measurements to assess potential bioeffects because bioaccumulation is not a bioeffect. Caging provides a unique opportunity to make synoptic measurements of each and facilitates making these measurements over space and time. Measuring bioaccumulation in resident and transplanted bivalves has probably been the most frequently used form of an in-situ bioassay because bivalves concentrate chemicals in their tissues. They are also easy to collect, cage, and measure. The authors have refined bivalve bioassay methods by minimizing the size range of test animals, making repetitive measurements of the same individuals, and standardizing test protocols for a variety of applications. They are now attempting to standardize criteria for accepting and interpreting data in the same way that laboratory bioassays have been standardized. Growth measurements can serve two purposes in this assessment strategy: (1) An integrated biological response endpoint that is easily quantifiable and with significance to the population, and (2) A means of calibrating bioaccumulation by assessing the relative health and physiological state of tissues that have accumulated the chemicals. In general, the authors have found the highest bioconcentration factors associated with the highest growth rates, the highest concentrations ({micro}g/g) of chemicals in juvenile mussels, and the highest chemical content ({micro}g/animal) in adult mussels. Without accounting for possible dilution of chemical concentrations by tissue growth or magnification through degrowth, contaminant concentrations can be misleading. Examples are provided for the Sudbury River in Massachusetts (Elliptio complanata), San Diego Bay (Mytilus galloprovincialis), and the Harbor Island Superfund Site in Puget Sound (Mytilus trossulus).

  8. A Multichannel Bioluminescence Determination Platform for Bioassays.

    PubMed

    Kim, Sung-Bae; Naganawa, Ryuichi

    2016-01-01

    The present protocol introduces a multichannel bioluminescence determination platform allowing a high sample throughput determination of weak bioluminescence with reduced standard deviations. The platform is designed to carry a multichannel conveyer, an optical filter, and a mirror cap. The platform enables us to near-simultaneously determine ligands in multiple samples without the replacement of the sample tubes. Furthermore, the optical filters beneath the multichannel conveyer are designed to easily discriminate colors during assays. This optical system provides excellent time- and labor-efficiency to users during bioassays. PMID:27424912

  9. Nuclear Thermal Propulsion (NTP): A Proven Growth Technology for Human NEO/Mars Exploration Missions

    NASA Technical Reports Server (NTRS)

    Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

    2012-01-01

    The nuclear thermal rocket (NTR) represents the next "evolutionary step" in high performance rocket propulsion. Unlike conventional chemical rockets that produce their energy through combustion, the NTR derives its energy from fission of Uranium-235 atoms contained within fuel elements that comprise the engine s reactor core. Using an "expander" cycle for turbopump drive power, hydrogen propellant is raised to a high pressure and pumped through coolant channels in the fuel elements where it is superheated then expanded out a supersonic nozzle to generate high thrust. By using hydrogen for both the reactor coolant and propellant, the NTR can achieve specific impulse (Isp) values of 900 seconds (s) or more - twice that of today s best chemical rockets. From 1955 - 1972, twenty rocket reactors were designed, built and ground tested in the Rover and NERVA (Nuclear Engine for Rocket Vehicle Applications) programs. These programs demonstrated: (1) high temperature carbide-based nuclear fuels; (2) a wide range of thrust levels; (3) sustained engine operation; (4) accumulated lifetime at full power; and (5) restart capability - all the requirements needed for a human Mars mission. Ceramic metal "cermet" fuel was pursued as well, as a backup option. The NTR also has significant "evolution and growth" capability. Configured as a "bimodal" system, it can generate its own electrical power to support spacecraft operational needs. Adding an oxygen "afterburner" nozzle introduces a variable thrust and Isp capability and allows bipropellant operation. In NASA s recent Mars Design Reference Architecture (DRA) 5.0 study, the NTR was selected as the preferred propulsion option because of its proven technology, higher performance, lower launch mass, versatile vehicle design, simple assembly, and growth potential. In contrast to other advanced propulsion options, no large technology scale-ups are required for NTP either. In fact, the smallest engine tested during the Rover program

  10. The Numerical Tokamak Project (NTP) simulation of turbulent transport in the core plasma: A grand challenge in plasma physics

    SciTech Connect

    Not Available

    1993-12-01

    The long-range goal of the Numerical Tokamak Project (NTP) is the reliable prediction of tokamak performance using physics-based numerical tools describing tokamak physics. The NTP is accomplishing the development of the most advanced particle and extended fluid model`s on massively parallel processing (MPP) environments as part of a multi-institutional, multi-disciplinary numerical study of tokamak core fluctuations. The NTP is a continuing focus of the Office of Fusion Energy`s theory and computation program. Near-term HPCC work concentrates on developing a predictive numerical description of the core plasma transport in tokamaks driven by low-frequency collective fluctuations. This work addresses one of the greatest intellectual challenges to our understanding of the physics of tokamak performance and needs the most advanced computational resources to progress. We are conducting detailed comparisons of kinetic and fluid numerical models of tokamak turbulence. These comparisons are stimulating the improvement of each and the development of hybrid models which embody aspects of both. The combination of emerging massively parallel processing hardware and algorithmic improvements will result in an estimated 10**2--10**6 performance increase. Development of information processing and visualization tools is accelerating our comparison of computational models to one another, to experimental data, and to analytical theory, providing a bootstrap effect in our understanding of the target physics. The measure of success is the degree to which the experimentally observed scaling of fluctuation-driven transport may be predicted numerically. The NTP is advancing the HPCC Initiative through its state-of-the-art computational work. We are pushing the capability of high performance computing through our efforts which are strongly leveraged by OFE support.

  11. The Manufacture of W-UO2 Fuel Elements for NTP Using the Hot Isostatic Pressing Consolidation Process

    NASA Technical Reports Server (NTRS)

    Broadway, Jeramie; Hickman, Robert; Mireles, Omar

    2012-01-01

    NTP is attractive for space exploration because: (1) Higher Isp than traditional chemical rockets (2)Shorter trip times (3) Reduced propellant mass (4) Increased payload. Lack of qualified fuel material is a key risk (cost, schedule, and performance). Development of stable fuel form is a critical path, long lead activity. Goals of this project are: Mature CERMET and Graphite based fuel materials and Develop and demonstrate critical technologies and capabilities.

  12. Urine sample collection protocols for bioassay samples

    SciTech Connect

    MacLellan, J.A.; McFadden, K.M.

    1992-11-01

    In vitro radiobioassay analyses are used to measure the amount of radioactive material excreted by personnel exposed to the potential intake of radioactive material. The analytical results are then used with various metabolic models to estimate the amount of radioactive material in the subject`s body and the original intake of radioactive material. Proper application of these metabolic models requires knowledge of the excretion period. It is normal practice to design the bioassay program based on a 24-hour excretion sample. The Hanford bioassay program simulates a total 24-hour urine excretion sample with urine collection periods lasting from one-half hour before retiring to one-half hour after rising on two consecutive days. Urine passed during the specified periods is collected in three 1-L bottles. Because the daily excretion volume given in Publication 23 of the International Commission on Radiological Protection (ICRP 1975, p. 354) for Reference Man is 1.4 L, it was proposed to use only two 1-L bottles as a cost-saving measure. This raised the broader question of what should be the design capacity of a 24-hour urine sample kit.

  13. Urine sample collection protocols for bioassay samples

    SciTech Connect

    MacLellan, J.A.; McFadden, K.M.

    1992-11-01

    In vitro radiobioassay analyses are used to measure the amount of radioactive material excreted by personnel exposed to the potential intake of radioactive material. The analytical results are then used with various metabolic models to estimate the amount of radioactive material in the subject's body and the original intake of radioactive material. Proper application of these metabolic models requires knowledge of the excretion period. It is normal practice to design the bioassay program based on a 24-hour excretion sample. The Hanford bioassay program simulates a total 24-hour urine excretion sample with urine collection periods lasting from one-half hour before retiring to one-half hour after rising on two consecutive days. Urine passed during the specified periods is collected in three 1-L bottles. Because the daily excretion volume given in Publication 23 of the International Commission on Radiological Protection (ICRP 1975, p. 354) for Reference Man is 1.4 L, it was proposed to use only two 1-L bottles as a cost-saving measure. This raised the broader question of what should be the design capacity of a 24-hour urine sample kit.

  14. Stopped-flow DNA polymerase assay by continuous monitoring of dNTP incorporation by fluorescence.

    PubMed

    Montgomery, Jesse L; Rejali, Nick; Wittwer, Carl T

    2013-10-15

    DNA polymerase activity was measured by a stopped-flow assay that monitors polymerase extension using an intercalating dye. Double-stranded DNA formation during extension of a hairpin substrate was monitored at 75°C for 2 min. Rates were determined in nucleotides per second per molecule of polymerase (nt/s) and were linear with time and polymerase concentration from 1 to 50 nM. The concentrations of 15 available polymerases were quantified and their extension rates determined in 50 mM Tris, pH 8.3, 0.5 mg/ml BSA, 2 mM MgCl₂, and 200 μM each dNTP as well as their commercially recommended buffers. Native Taq polymerases had similar extension rates of 10-45 nt/s. Three alternative polymerases showed faster speeds, including KOD (76 nt/s), Klentaq I (101 nt/s), and KAPA2G (155 nt/s). Fusion polymerases including Herculase II and Phusion were relatively slow (3-13 nt/s). The pH optimum for Klentaq extension was between 8.5 and 8.7 with no effect of Tris concentration. Activity was directly correlated to the MgCl2 concentration and inversely correlated to the KCl concentration. This continuous assay is relevant to PCR and provides accurate measurement of polymerase activity using a defined template without the need of radiolabeled substrates. PMID:23872003

  15. Subscale Validation of the Subsurface Active Filtration of Exhaust (SAFE) Approach to NTP Ground Testing

    NASA Technical Reports Server (NTRS)

    Marshall, William M.; Borowski, Stanley K.; Bulman, Mel; Joyner, Russell; Martin, Charles R.

    2015-01-01

    Brief History of NTP: Project Rover Began in 1950s by Los Alamos Scientific Labs (now Los Alamos National Labs) and ran until 1970s Tested a series of nuclear reactor engines of varying size at Nevada Test Site (now Nevada National Security Site) Ranged in scale from 111 kN (25 klbf) to 1.1 MN (250 klbf) Included Nuclear Furnace-1 tests Demonstrated the viability and capability of a nuclear rocket engine test program One of Kennedys 4 goals during famous moon speech to Congress Nuclear Engines for Rocket Vehicle Applications (NERVA) Atomic Energy Commission and NASA joint venture started in 1964 Parallel effort to Project Rover was focused on technology demonstration Tested XE engine, a 245-kN (55-klbf) engine to demonstrate startup shutdown sequencing. Hot-hydrogen stream is passed directly through fuel elements potential for radioactive material to be eroded into gaseous fuel flow as identified in previous programs NERVA and Project Rover (1950s-70s) were able to test in open atmosphere similar to conventional rocket engine test stands today Nuclear Furance-1 tests employed a full scrubber system Increased government and environmental regulations prohibit the modern testing in open atmosphere. Since the 1960s, there has been an increasing cessation on open air testing of nuclear material Political and national security concerns further compound the regulatory environment

  16. Appplication of a general fluid mechanics program to NTP system modeling

    NASA Astrophysics Data System (ADS)

    Lee, Stacey K.

    1993-01-01

    An effort is currently underway at NASA and the Department of Energy (DOE) to develop an accurate model for predicting nuclear thermal propulsion (NTP) system performance. The objective of the effort is to develop several levels of computer programs which vary in detail and complexity according to user's needs. The current focus is on the Level 1 steady-state, parametric system model. This system model will combine a general fluid mechanics program, SAFSIM, with the ability to analyze turbines, pumps, nozzles, and reactor physics. SAFSIM (System Analysis Flow SIMulator) is a FORTRAN computer program that simulates integrated performance of systems involving fluid mechanics, heat transfer, and reactor dynamics. SAFSIM has the versatility to allow simulation of almost any system, including a nuclear reactor system. The focus of this paper is the validation of SAFSIM's capabilities as a base computational engine for a nuclear thermal propulsion system model. Validation is being accomplished by modeling of a nuclear engine test using SAFSIM and comparing the results to known experimental data. For this study, the NRX/EST test was chosen; it was the first of the tests to demonstrate the integration of all system components (including the turbopump) and it utilized the hot bleed cycle. This paper present a comparison of analytical results with experimental system performance in terms of state points, mass flow rates, wall temperatures, and specific impulse. In addition, the methodology used in the validation efforts will be discussed.

  17. Extreme dNTP pool changes and hypermutability in dcd ndk strains.

    PubMed

    Tse, Lawrence; Kang, Tina Manzhu; Yuan, Jessica; Mihora, Danielle; Becket, Elinne; Maslowska, Katarzyna H; Schaaper, Roel M; Miller, Jeffrey H

    2016-01-01

    Cells lacking deoxycytidine deaminase (DCD) have been shown to have imbalances in the normal dNTP pools that lead to multiple phenotypes, including increased mutagenesis, increased sensitivity to oxidizing agents, and to a number of antibiotics. In particular, there is an increased dCTP pool, often accompanied by a decreased dTTP pool. In the work presented here, we show that double mutants of Escherichia coli lacking both DCD and NDK (nucleoside diphosphate kinase) have even more extreme imbalances of dNTPs than mutants lacking only one or the other of these enzymes. In particular, the dCTP pool rises to very high levels, exceeding even the cellular ATP level by several-fold. This increased level of dCTP, coupled with more modest changes in other dNTPs, results in exceptionally high mutation levels. The high mutation levels are attenuated by the addition of thymidine. The results corroborate the critical importance of controlling DNA precursor levels for promoting genome stability. We also show that the addition of certain exogenous nucleosides can influence replication errors in DCD-proficient strains that are deficient in mismatch repair. PMID:26789486

  18. Aspirator Gun for High-Throughput Mosquito Bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We describe an innovative aspirator gun designed to transfer anaesthetized mosquitoes directly into glass bioassay tubes. The gun has been used for thousands of transfers with extremely low associated mortality and is the central component of a high-throughput bioassay system. The gun is constructed...

  19. COLLECTION, CHEMICAL FRACTIONATION, AND MUTAGENICITY BIOASSAY OF AMBIENT AIR PARTICULATE

    EPA Science Inventory

    The influence of industrialization and consequent increased concentration of urban particulate matter on the incidence of cancer has long been a concern. The first bioassays used to evaluate complex ambient air samples were whole-animal carcinogenesis bioassays. In these studies,...

  20. Aspirator gun for high-throughput mosquito bioassays.

    PubMed

    Aldridge, Robert L; Wynn, W Wayne; Britch, Seth C; Linthicum, Kenneth J

    2012-03-01

    We describe an innovative aspirator gun designed to transfer individual anesthetized mosquitoes directly into glass bioassay tubes. The gun has been used for thousands of transfers with extremely low associated mortality and is the central component of a high-throughput bioassay system. The gun is constructed using readily obtainable materials and can be modified for a range of insects. PMID:22533090

  1. Bioassay vs. Air Sampling: Practical Guidance and Experience at Hanford

    SciTech Connect

    Carbaugh, Eugene H.; Carlson, Eric W.; Hill, Robin L.

    2004-02-08

    The Hanford Site has implemented a policy to guide in determining whether air sampling data or special fecal bioassay data are more appropriate for determining doses of record for low-level plutonium exposures. The basis for the policy and four years of experience in comparing DAC-hours exposure with bioassay-based dosimetry is discussed.

  2. Signal Amplification of Bioassay Using Zinc Nanomaterials

    NASA Astrophysics Data System (ADS)

    Cowles, Chad L.

    An emerging trend in the analytical detection sciences is the employment of nanomaterials for bioassay signal transduction to identify analytes critical to public health. These nanomaterials have been specifically investigated for applications which require identification of trace levels of cells, proteins, or other molecules that can have broad ranging impacts to human health in fields such as clinical diagnostics, environmental monitoring, food and drink control, and the prevention of bioterrorism. Oftentimes these nanoparticle-based signal transduction or amplification approaches offer distinct advantages over conventional methods such as increased sensitivity, rapidity, or stability. The biological application of nanoparticles however, does suffer from drawbacks that have limited more widespread adoption of these techniques. Some of these drawbacks are, high cost and toxicity, arduous synthesis methods, functionalization and bioconjugation challenges, and laboratory disposal and environmental hazard issues, all of which have impeded the progression of this technology in some way or another. This work aims at developing novel techniques that offer solutions to a number of these hurdles through the development of new nanoparticle-based signal transduction approaches and the description of a previously undescribed nanomaterial. Zinc-based nanomaterials offer the opportunity to overcome some of the limitations that are encountered when other nanomaterials are employed for bioassay signal transduction. On the other hand, the biological application of zinc nanomaterials has been difficult because in general their fluorescence is in the blue range and the reported quantum yields are usually too low for highly sensitive applications. The advantages of using zinc nanomaterials for biological applications, such as reduced toxicity, simple synthesis, low cost, and straightforward functionalization strategies contribute to the research interest in their application as

  3. FY 1986 budget highlights

    SciTech Connect

    Not Available

    1985-02-01

    The FY 1986 budget request for DOE supports the energy, general science and defense missions of the Department in a comprehensive manner, while being responsive to the President's directive to all Federal agencies to freeze or reduce Government spending wherever possible to reduce the Federal deficit. The discussion displays the budget in a format designed to emphasize the varied activities of DOE. ''Research and Development'' describes the nature of the scientific and technical effort which underlies the Department's programs in a number of areas, such as energy, general science, and weapons research, which previously appeared in three distinct sections of our budget presentation. ''Defense Production and Support'' highlights a significant element of our defense activities which have production, whether of weapons or materials, as a common thread. ''Waste Activities'' combines programs from the civilian and defense areas to bring attention to a major effort of DOE ''Business Enterprises'' focuses attention on the fact that a number of the Department's activities are operated like businesses, marketing products and generating revenues. ''Grants and Other Energy Functions'' is how we group non-research and development grant programs and such essential activities as energy information and regulation. Finally, ''Department Management'' includes the various ''overhead'' organizations which keep the Department functioning at headquarters and in the field.

  4. 1999 NCCS Highlights

    NASA Technical Reports Server (NTRS)

    Bennett, Jerome (Technical Monitor)

    2002-01-01

    The NASA Center for Computational Sciences (NCCS) is a high-performance scientific computing facility operated, maintained and managed by the Earth and Space Data Computing Division (ESDCD) of NASA Goddard Space Flight Center's (GSFC) Earth Sciences Directorate. The mission of the NCCS is to advance leading-edge science by providing the best people, computers, and data storage systems to NASA's Earth and space sciences programs and those of other U.S. Government agencies, universities, and private institutions. Among the many computationally demanding Earth science research efforts supported by the NCCS in Fiscal Year 1999 (FY99) are the NASA Seasonal-to-Interannual Prediction Project, the NASA Search and Rescue Mission, Earth gravitational model development efforts, the National Weather Service's North American Observing System program, Data Assimilation Office studies, a NASA-sponsored project at the Center for Ocean-Land-Atmosphere Studies, a NASA-sponsored microgravity project conducted by researchers at the City University of New York and the University of Pennsylvania, the completion of a satellite-derived global climate data set, simulations of a new geodynamo model, and studies of Earth's torque. This document presents highlights of these research efforts and an overview of the NCCS, its facilities, and its people.

  5. Voyager: Neptune Encounter Highlights

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Voyager encounter data are presented in computer animation (CA) and real (R) animation. The highlights include a view of 2 full rotations of Neptune. It shows spacecraft trajectory 'diving' over Neptune and intercepting Triton's orbit, depicting radiation and occulation zones. Also shown are a renegade orbit of Triton and Voyager's encounter with Neptune's Magnetopause. A model of the spacecraft's complex maneuvers during close encounters of Neptune and Triton is presented. A view from Earth of Neptune's occulation experiment is is shown as well as a recreation of Voyager's final pass. There is detail of Voyager's Image Compensation technique which produces Voyager images. Eighteen images were produced on June 22 - 23, 1989, from 57 million miles away. A 68 day sequence which provides a stroboscopic view - colorization approximates what is seen by the human eye. Real time images recorded live from Voyager on 8/24/89 are presented. Photoclinometry produced the topography of Triton. Three images are used to create a sequence of Neptune's rings. The globe of Neptune and 2 views of the south pole are shown as well as Neptune rotating. The rotation of a scooter is frozen in images showing differential motion. There is a view of rotation of the Great Dark Spot about its own axis. Photoclinometry provides a 3-dimensional perspective using a color mosaic of Triton images. The globe is used to indicate the orientation of Neptune's crescent. The east and west plumes on Triton are shown.

  6. Circular Bioassay Platforms for Applications in Microwave-Accelerated Techniques

    PubMed Central

    Mohammed, Muzaffer; Clement, Travis C.; Aslan, Kadir

    2014-01-01

    In this paper, we present the design of four different circular bioassay platforms, which are suitable for homogeneous microwave heating, using theoretical calculations (i.e., COMSOL™ multiphysics software). Circular bioassay platforms are constructed from poly(methyl methacrylate) (PMMA) for optical transparency between 400–800 nm, has multiple sample capacity (12, 16, 19 and 21 wells) and modified with silver nanoparticle films (SNFs) to be used in microwave-accelerated bioassays (MABs). In addition, a small monomode microwave cavity, which can be operated with an external microwave generator (100 W), for use with the bioassay platforms in MABs is also developed. Our design parameters for the circular bioassay platforms and monomode microwave cavity during microwave heating were: (i) temperature profiles, (ii) electric field distributions, (iii) location of the circular bioassay platforms inside the microwave cavity, and (iv) design and number of wells on the circular bioassay platforms. We have also carried out additional simulations to assess the use of circular bioassay platforms in a conventional kitchen microwave oven (e.g., 900 W). Our results show that the location of the circular bioassay platforms in the microwave cavity was predicted to have a significant effect on the homogeneous heating of these platforms. The 21-well circular bioassay platform design in our monomode microwave cavity was predicted to offer a homogeneous heating pattern, where inter-well temperature was observed to be in between 23.72–24.13°C and intra-well temperature difference was less than 0.21°C for 60 seconds of microwave heating, which was also verified experimentally. PMID:25568813

  7. Plasmonically amplified fluorescence bioassay with microarray format

    NASA Astrophysics Data System (ADS)

    Gogalic, S.; Hageneder, S.; Ctortecka, C.; Bauch, M.; Khan, I.; Preininger, Claudia; Sauer, U.; Dostalek, J.

    2015-05-01

    Plasmonic amplification of fluorescence signal in bioassays with microarray detection format is reported. A crossed relief diffraction grating was designed to couple an excitation laser beam to surface plasmons at the wavelength overlapping with the absorption and emission bands of fluorophore Dy647 that was used as a label. The surface of periodically corrugated sensor chip was coated with surface plasmon-supporting gold layer and a thin SU8 polymer film carrying epoxy groups. These groups were employed for the covalent immobilization of capture antibodies at arrays of spots. The plasmonic amplification of fluorescence signal on the developed microarray chip was tested by using interleukin 8 sandwich immunoassay. The readout was performed ex situ after drying the chip by using a commercial scanner with high numerical aperture collecting lens. Obtained results reveal the enhancement of fluorescence signal by a factor of 5 when compared to a regular glass chip.

  8. Superluminescent variants of marine luciferases for bioassays.

    PubMed

    Kim, Sung Bae; Suzuki, Hideyuki; Sato, Moritoshi; Tao, Hiroaki

    2011-11-15

    In this study, a rational synthesis of superluminescent variants from marine luciferases with prolonged bioluminescence has been demonstrated. A putative active site of a model marine luciferase, Gaussia princeps Luciferase (GLuc), was assigned and modified by a site-directed mutagenesis. The potent variants were found to generate up to 10 times stronger bioluminescence, emitting red shifts of up to 33 nm with natural coelenterazine than native GLuc, rendering an efficient optical signature in bioassays. The advantageous properties were demonstrated with mammalian two-hybrid assays, single-chain probes, and metastases of murine B16 melanoma in BALB/c nude mice. The unique ideas for engineering GLuc are proved to be valid even for other marine luciferases. PMID:21951281

  9. Modelling larval movement data from individual bioassays.

    PubMed

    McLellan, Chris R; Worton, Bruce J; Deasy, William; Birch, A Nicholas E

    2015-05-01

    We consider modelling the movements of larvae using individual bioassays in which data are collected at a high-frequency rate of five observations per second. The aim is to characterize the behaviour of the larvae when exposed to attractant and repellent compounds. Mixtures of diffusion processes, as well as Hidden Markov models, are proposed as models of larval movement. These models account for directed and localized movements, and successfully distinguish between the behaviour of larvae exposed to attractant and repellent compounds. A simulation study illustrates the advantage of using a Hidden Markov model rather than a simpler mixture model. Practical aspects of model estimation and inference are considered on extensive data collected in a study of novel approaches for the management of cabbage root fly. PMID:25764283

  10. Cell-based bioassays in microfluidic systems

    NASA Astrophysics Data System (ADS)

    Itle, Laura J.; Zguris, Jeanna C.; Pishko, Michael V.

    2004-12-01

    The development of cell-based bioassays for high throughput drug screening or the sensing of biotoxins is contingent on the development of whole cell sensors for specific changes in intracellular conditions and the integration of those systems into sample delivery devices. Here we show the feasibility of using a 5-(and-6)-carboxy SNARF-1, acetoxymethyl ester, acetate, a fluorescent dye capable of responding to changes in intracellular pH, as a detection method for the bacterial endotoxin, lipopolysaccharide. We used photolithography to entrap cells with this dye within poly(ethylene) glyocol diacrylate hydrogels in microfluidic channels. After 18 hours of exposure to lipopolysaccharide, we were able to see visible changes in the fluorescent pattern. This work shows the feasibility of using whole cell based biosensors within microfluidic networks to detect cellular changes in response to exogenous agents.

  11. STS-70 mission highlights

    NASA Astrophysics Data System (ADS)

    1995-09-01

    The highlights of the STS-70 mission are presented in this video. The flight crew consisted of Cmdr. John Hendricks, Pilot Kevin Kregel, Flight Engineer Nancy Curie, and Mission Specialists Dr. Don Thomas and Dr. Mary Ellen Weber. The mission's primary objective was the deployment of the 7th Tracking Data and Relay Satellite (TDRS), which will provide a communication, tracking, telemetry, data acquisition, and command services space-based network system essential to low Earth orbital spacecraft. Secondary mission objectives included activating and studying the Physiological and Anatomical Rodent Experiment/National Institutes of Health-Rodents (PARE/NIH-R), The Bioreactor Demonstration System (BDS), the Commercial Protein Crystal Growth (CPCG) studies, the Space Tissue Loss/National Institutes of Health-Cells (STL/NIH-C) experiment, the Biological Research in Canisters (BRIC) experiment, Shuttle Amateur Radio Experiment-2 (SAREX-2), the Visual Function Tester-4 (VFT-4), the Hand-Held, Earth Oriented, Real-Time, Cooperative, User-Friendly, Location-Targeting and Environmental System (HERCULES), the Microcapsules in Space-B (MIS-B) experiment, the Windows Experiment (WINDEX), the Radiation Monitoring Equipment-3 (RME-3), and the Military Applications of Ship Tracks (MAST) experiment. There was an in-orbit dedication ceremony by the spacecrew and the newly Integrated Mission Control Center to commemorate the Center's integration. The STS-70 mission was the first mission monitored by this new control center. Earth views included the Earth's atmosphere, a sunrise over the Earth's horizon, several views of various land masses, some B/W lightning shots, some cloud cover, and a tropical storm.

  12. Highlights of Astronomy

    NASA Astrophysics Data System (ADS)

    van der Hucht, Karel

    2008-02-01

    Preface Karel A. van der Hucht; Part I. Invited Discourses: Part II. Joint Discussions: 1. Particle acceleration - from Solar System to AGN Marian Karlicky and John C. Brown; 2. Pulsar emission and related phenomena Werner Becker, Janusz A. Gil and Bronislaw Rudak; 3. Solar activity regions and magnetic structure Debi Prasad Choudhary and Michal Sobotka; 4. The ultraviolet universe: Stars from birth to death Ana I. Gomez de Castro and Martin A. Barstow; 5. Calibrating the top of the stellar M-L relationship Claus Leitherer, Anthony F. J. Moat and Joachim Puls; 6. Neutron stars and black holes in star clusters Frederic A. Rasio; 7. The Universe at z > 6 Daniel Schaerer and Andrea Ferrara; 8. Solar and stellar activity cycles Klaus G. Strassmeier and Alexander Kosovichev; 9. Supernovae: One millennium after SN 1006 P. Frank Winkler, Wolfgang Hillebrandt and Brian P. Schmidt; 10. Progress in planetary exploration missions Guy J. Consolmagno; 11. Pre-solar grains as astrophysical tools Anja C. Andersen and John C. Lattanzio; 12. Long wavelength astrophysics T. Joseph W. Lazio and Namir E. Kassim; 13. Exploiting large surveys for galactic astronomy Christopher J. Corbally, Coryn A. L. Bailer-Jones, Sunetra Giridhar and Thomas H. Lloyd Evans; 14. Modeling dense stellar systems Alison I. Sills, Ladislav Subr and Simon F. Portegies Zwart; 15. New cosmology results from the Spitzer Space Telescope George Helou and David T. Frayer; 16. Nomenclature, precession and new models in fundamental astronomy Nicole Capitaine, Jan Vondrak & James L. Hilton; 17. Highlights of recent progress in seismology of the Sun and Sun-like stars John W. Leibacher and Michael J. Thompson; Part III. Special Sessions: SpS 1. Large astronomical facilities of the next decade Gerard F. Gilmore and Richard T. Schilizzi; SpS 2. Innovation in teaching and learning astronomy methods Rosa M. Ros and Jay M. Pasachoff; SpS 3. The Virtual Observatory in action: New science, new technology and next

  13. Experimental and Computational Characterization of Biological Liquid Crystals: A Review of Single-Molecule Bioassays

    PubMed Central

    Eom, Kilho; Yang, Jaemoon; Park, Jinsung; Yoon, Gwonchan; Soo Sohn, Young; Park, Shinsuk; Yoon, Dae Sung; Na, Sungsoo; Kwon, Taeyun

    2009-01-01

    Quantitative understanding of the mechanical behavior of biological liquid crystals such as proteins is essential for gaining insight into their biological functions, since some proteins perform notable mechanical functions. Recently, single-molecule experiments have allowed not only the quantitative characterization of the mechanical behavior of proteins such as protein unfolding mechanics, but also the exploration of the free energy landscape for protein folding. In this work, we have reviewed the current state-of-art in single-molecule bioassays that enable quantitative studies on protein unfolding mechanics and/or various molecular interactions. Specifically, single-molecule pulling experiments based on atomic force microscopy (AFM) have been overviewed. In addition, the computational simulations on single-molecule pulling experiments have been reviewed. We have also reviewed the AFM cantilever-based bioassay that provides insight into various molecular interactions. Our review highlights the AFM-based single-molecule bioassay for quantitative characterization of biological liquid crystals such as proteins. PMID:19865530

  14. Mini-MITEE: Ultra Small, Ultra Light NTP Engines for Robotic Science and Manned Exploration Missions

    NASA Astrophysics Data System (ADS)

    Powell, James; Maise, George; Paniagua, John

    2006-01-01

    A compact, ultra lightweight Nuclear Thermal Propulsion (NTP) engine design is described with the capability to carry out a wide range of unique and important robotic science missions that are not possible using chemical or Nuclear Electric Propulsion (NEP). The MITEE (MInature ReacTor EnginE) reactor uses hydrogeneous moderator, such as solid lithium-7 hydride, and high temperature cermet tungsten/UO2 nuclear fuel. The reactor is configured as a modular pressure tube assembly, with each pressure tube containing an outer annual shell of moderator with an inner annular region of W/UO2 cermet fuel sheets. H2 propellant flows radially inwards through the moderator and fuel regions, exiting at ~3000 K into a central channel that leads to a nozzle at the end of the pressure tube. Power density in the fuel region is 10 to 20 megawatts per liter, depending on design, producing a thrust output on the order of 15,000 Newtons and an Isp of ~1000 seconds. 3D Monte Carlo neutronic analyses are described for MITEE reactors utilizing various fissile fuel options (U-235, U-233, and Am242m) and moderators (7LiH and BeH2). Reactor mass ranges from a maximum of 100 kg for the 7LiH/U-235 option to a minimum of 28 kg for the BeH2/Am-242 m option. Pure thrust only and bi-modal (thrust plus electric power generation) MITEE designs are described. Potential unique robotic science missions enabled by the MITEE engine are described, including landing on Europa and exploring the ice sheet interior with return of samples to Earth, hopping to and exploring multiple sites on Mars, unlimited ramjet flight in the atmospheres of Jupiter, Saturn, Uranus, and Neptune and landing on, and sample return from Pluto.

  15. Stabilization of Poliovirus Polymerase by NTP Binding and Fingers-Thumb Interactions

    PubMed Central

    Thompson, Aaron A.; Albertini, Rebecca A.; Peersen, Olve B.

    2007-01-01

    The viral RNA-dependent RNA polymerases show a conserved structure where the fingers domain interacts with the top of the thumb domain to create a tunnel through which nucleotide triphosphates reach the active site. We have solved the crystal structures of poliovirus polymerase (3Dpol) in complex with all four NTPs, showing that they all bind in a common preinsertion site where the phosphates are not yet positioned over the active site. The NTPs interact with both the fingers and palm domains, forming bridging interactions that explain the increased thermal stability of 3Dpol in the presence of NTPs. We have also examined the importance of the fingers-thumb domain interaction for the function and structural stability of 3Dpol. Results from thermal denaturation experiments using circular dichroism and 2-aniliino-6-napthaline-sulfonate (ANS) fluorescence show that 3Dpol has a melting temperature of only ∼40°C. NTP binding stabilizes the protein and increases the melting by 5-6 °C while mutations in the fingers-thumb domain interface destabilize the protein and reduce the melting point by as much as 6 °C. In particular, the burial of Phe30 and Phe34 from the tip of the index finger into a pocket at the top of the thumb and the presence of Trp403 on the thumb domain are key interactions required to maintain the structural integrity of the polymerase. The data suggest the fingers domain has significant conformational flexibility and exists in a highly dynamic molten globule state at physiological temperature. The role of the enclosed active site motif as a structural scaffold for constraining the fingers domain and accommodating conformational changes in 3Dpol and other viral polymerases during the catalytic cycle is discussed. PMID:17223130

  16. Mini-MITEE: Ultra Small, Ultra Light NTP Engines for Robotic Science and Manned Exploration Missions

    SciTech Connect

    Powell, James; Maise, George; Paniagua, John

    2006-01-20

    A compact, ultra lightweight Nuclear Thermal Propulsion (NTP) engine design is described with the capability to carry out a wide range of unique and important robotic science missions that are not possible using chemical or Nuclear Electric Propulsion (NEP). The MITEE (MInature ReacTor EnginE) reactor uses hydrogeneous moderator, such as solid lithium-7 hydride, and high temperature cermet tungsten/UO2 nuclear fuel. The reactor is configured as a modular pressure tube assembly, with each pressure tube containing an outer annual shell of moderator with an inner annular region of W/UO2 cermet fuel sheets. H2 propellant flows radially inwards through the moderator and fuel regions, exiting at {approx}3000 K into a central channel that leads to a nozzle at the end of the pressure tube. Power density in the fuel region is 10 to 20 megawatts per liter, depending on design, producing a thrust output on the order of 15,000 Newtons and an Isp of {approx}1000 seconds. 3D Monte Carlo neutronic analyses are described for MITEE reactors utilizing various fissile fuel options (U-235, U-233, and Am242m) and moderators (7LiH and BeH2). Reactor mass ranges from a maximum of 100 kg for the 7LiH/U-235 option to a minimum of 28 kg for the BeH2/Am-242 m option. Pure thrust only and bi-modal (thrust plus electric power generation) MITEE designs are described. Potential unique robotic science missions enabled by the MITEE engine are described, including landing on Europa and exploring the ice sheet interior with return of samples to Earth, hopping to and exploring multiple sites on Mars, unlimited ramjet flight in the atmospheres of Jupiter, Saturn, Uranus, and Neptune and landing on, and sample return from Pluto.

  17. ESO Highlights in 2008

    NASA Astrophysics Data System (ADS)

    2009-01-01

    As is now the tradition, the European Southern Observatory looks back at the exciting moments of last year. 2008 was in several aspects an exceptionally good year. Over the year, ESO's telescopes provided data for more than 700 scientific publications in refereed journals, making ESO the most productive ground-based observatory in the world. ESO PR Highlights 2008 ESO PR Photo 01a/09 The image above is a clickable map. These are only some of the press releases issued by ESO in 2008. For a full listing, please go to ESO 2008 page. Austria signed the agreement to join the other 13 ESO member states (ESO 11/08 and 20/08), while the year marked the 10th anniversary of first light for ESO's "perfect science machine", the Very Large Telescope (ESO 16/08 and 17/08). The ALMA project, for which ESO is the European partner, had a major milestone in December, as the observatory was equipped with its first antenna (ESO 49/08). Also the Atacama Pathfinder Experiment (APEX) telescope impressed this year with some very impressive and publicly visible results. Highlights came in many fields: Astronomers for instance used the Very Large Telescope (VLT) to discover and image a probable giant planet long sought around the star Beta Pictoris (ESO 42/08). This is now the eighth extrasolar planet to have been imaged since the VLT imaged the first extrasolar planet in 2004 (three of eight were imaged with VLT). The VLT also enabled three students to confirm the nature of a unique planet (ESO 45/08). This extraordinary find, which turned up during their research project, is a planet about five times as massive as Jupiter. This is the first planet discovered orbiting a fast-rotating hot star. The world's foremost planet-hunting instrument, HARPS, located at ESO's La Silla observatory, scored a new first, finding a system of three super-Earths around a star (ESO 19/08). Based on the complete HARPS sample, astronomers now think that one Sun-like star out of three harbours short orbit, low

  18. ESO Highlights in 2008

    NASA Astrophysics Data System (ADS)

    2009-01-01

    As is now the tradition, the European Southern Observatory looks back at the exciting moments of last year. 2008 was in several aspects an exceptionally good year. Over the year, ESO's telescopes provided data for more than 700 scientific publications in refereed journals, making ESO the most productive ground-based observatory in the world. ESO PR Highlights 2008 ESO PR Photo 01a/09 The image above is a clickable map. These are only some of the press releases issued by ESO in 2008. For a full listing, please go to ESO 2008 page. Austria signed the agreement to join the other 13 ESO member states (ESO 11/08 and 20/08), while the year marked the 10th anniversary of first light for ESO's "perfect science machine", the Very Large Telescope (ESO 16/08 and 17/08). The ALMA project, for which ESO is the European partner, had a major milestone in December, as the observatory was equipped with its first antenna (ESO 49/08). Also the Atacama Pathfinder Experiment (APEX) telescope impressed this year with some very impressive and publicly visible results. Highlights came in many fields: Astronomers for instance used the Very Large Telescope (VLT) to discover and image a probable giant planet long sought around the star Beta Pictoris (ESO 42/08). This is now the eighth extrasolar planet to have been imaged since the VLT imaged the first extrasolar planet in 2004 (three of eight were imaged with VLT). The VLT also enabled three students to confirm the nature of a unique planet (ESO 45/08). This extraordinary find, which turned up during their research project, is a planet about five times as massive as Jupiter. This is the first planet discovered orbiting a fast-rotating hot star. The world's foremost planet-hunting instrument, HARPS, located at ESO's La Silla observatory, scored a new first, finding a system of three super-Earths around a star (ESO 19/08). Based on the complete HARPS sample, astronomers now think that one Sun-like star out of three harbours short orbit, low

  19. PubChem BioAssay: 2014 update.

    PubMed

    Wang, Yanli; Suzek, Tugba; Zhang, Jian; Wang, Jiyao; He, Siqian; Cheng, Tiejun; Shoemaker, Benjamin A; Gindulyte, Asta; Bryant, Stephen H

    2014-01-01

    PubChem's BioAssay database (http://pubchem.ncbi.nlm.nih.gov) is a public repository for archiving biological tests of small molecules generated through high-throughput screening experiments, medicinal chemistry studies, chemical biology research and drug discovery programs. In addition, the BioAssay database contains data from high-throughput RNA interference screening aimed at identifying critical genes responsible for a biological process or disease condition. The mission of PubChem is to serve the community by providing free and easy access to all deposited data. To this end, PubChem BioAssay is integrated into the National Center for Biotechnology Information retrieval system, making them searchable by Entrez queries and cross-linked to other biomedical information archived at National Center for Biotechnology Information. Moreover, PubChem BioAssay provides web-based and programmatic tools allowing users to search, access and analyze bioassay test results and metadata. In this work, we provide an update for the PubChem BioAssay resource, such as information content growth, new developments supporting data integration and search, and the recently deployed PubChem Upload to streamline chemical structure and bioassay submissions. PMID:24198245

  20. PubChem BioAssay: 2014 update

    PubMed Central

    Wang, Yanli; Suzek, Tugba; Zhang, Jian; Wang, Jiyao; He, Siqian; Cheng, Tiejun; Shoemaker, Benjamin A.; Gindulyte, Asta; Bryant, Stephen H.

    2014-01-01

    PubChem’s BioAssay database (http://pubchem.ncbi.nlm.nih.gov) is a public repository for archiving biological tests of small molecules generated through high-throughput screening experiments, medicinal chemistry studies, chemical biology research and drug discovery programs. In addition, the BioAssay database contains data from high-throughput RNA interference screening aimed at identifying critical genes responsible for a biological process or disease condition. The mission of PubChem is to serve the community by providing free and easy access to all deposited data. To this end, PubChem BioAssay is integrated into the National Center for Biotechnology Information retrieval system, making them searchable by Entrez queries and cross-linked to other biomedical information archived at National Center for Biotechnology Information. Moreover, PubChem BioAssay provides web-based and programmatic tools allowing users to search, access and analyze bioassay test results and metadata. In this work, we provide an update for the PubChem BioAssay resource, such as information content growth, new developments supporting data integration and search, and the recently deployed PubChem Upload to streamline chemical structure and bioassay submissions. PMID:24198245

  1. NTP-CERHR monograph on the potential human reproductive and developmental effects of di (2-ethylhexyl) phthalate (DEHP).

    PubMed

    Shelby, Michael D

    2006-11-01

    The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) conducted an updated evaluation of the potential for DEHP to cause adverse effects on reproduction and development in humans. The first CERHR expert panel evaluation of DEHP was completed in 2000 by the Phthalates Expert Panel. CERHR selected DEHP for an updated evaluation because of: (1) widespread human exposure, (2) public and government interest in adverse health effects, (3) recently available human exposure studies, and (4) the large number of relevant toxicity papers published since the earlier evaluation. DEHP (CAS RN: 117-81-7) is a high production volume chemical used as a plasticizer of polyvinyl chloride in the manufacture of a wide variety of consumer goods, such as building products, car products, clothing, food packaging, children's products (but not in toys intended for mouthing), and in medical devices made of polyvinyl chloride. The public can be exposed to DEHP by ingesting food, drink or dust that has been in contact with DEHP-containing materials, by inhaling contaminated air or dust, or by undergoing a medical procedure that uses polyvinyl chloride medical tubing or storage bags. It is estimated that the general population of the United States is exposed to DEHP levels ranging from 1 to 30 microg/kg bw/day (micrograms per kilogram body weight per day). The results of this DEHP update evaluation are published in an NTP-CERHR monograph that includes: (1) the NTP Brief, (2) the Expert Panel Update on the Reproductive and Developmental Toxicity of DEHP, and (3) public comments on the expert panel report. The NTP reached the following conclusions on the possible effects of exposure to DEHP on human development and reproduction. Note that the possible levels of concern, from lowest to highest, are negligible concern, minimal concern, some concern, concern, and serious concern. There is serious concern that certain intensive medical treatments of

  2. Nucleotide binding interactions modulate dNTP selectivity and facilitate 8-oxo-dGTP incorporation by DNA polymerase lambda

    PubMed Central

    Burak, Matthew J.; Guja, Kip E.; Garcia-Diaz, Miguel

    2015-01-01

    8-Oxo-7,8,-dihydro-2′-deoxyguanosine triphosphate (8-oxo-dGTP) is a major product of oxidative damage in the nucleotide pool. It is capable of mispairing with adenosine (dA), resulting in futile, mutagenic cycles of base excision repair. Therefore, it is critical that DNA polymerases discriminate against 8-oxo-dGTP at the insertion step. Because of its roles in oxidative DNA damage repair and non-homologous end joining, DNA polymerase lambda (Pol λ) may frequently encounter 8-oxo-dGTP. Here, we have studied the mechanisms of 8-oxo-dGMP incorporation and discrimination by Pol λ. We have solved high resolution crystal structures showing how Pol λ accommodates 8-oxo-dGTP in its active site. The structures indicate that when mispaired with dA, the oxidized nucleotide assumes the mutagenic syn-conformation, and is stabilized by multiple interactions. Steady-state kinetics reveal that two residues lining the dNTP binding pocket, Ala510 and Asn513, play differential roles in dNTP selectivity. Specifically, Ala510 and Asn513 facilitate incorporation of 8-oxo-dGMP opposite dA and dC, respectively. These residues also modulate the balance between purine and pyrimidine incorporation. Our results shed light on the mechanisms controlling 8-oxo-dGMP incorporation in Pol λ and on the importance of interactions with the incoming dNTP to determine selectivity in family X DNA polymerases. PMID:26220180

  3. Collection and control of tritium bioassay samples at Pantex

    SciTech Connect

    Fairrow, N.L.; Ivie, W.E.

    1992-01-01

    Pantex is the final assembly/disassembly point for US nuclear weapons. The Pantex internal dosimetry section monitors radiation workers once a month for tritium exposure. In order to manage collection and control of the bioassay specimens efficiently, a bar code system for collection of samples was developed and implemented to speed up the process and decrease the number of errors probable when transferring data. In the past, all the bioassay data from samples were entered manually into a computer database. Transferring the bioassay data from the liquid scintillation counter to each individual's dosimetry record required as much as two weeks of concentrated effort.

  4. Collection and control of tritium bioassay samples at Pantex

    SciTech Connect

    Fairrow, N.L.; Ivie, W.E.

    1992-12-31

    Pantex is the final assembly/disassembly point for US nuclear weapons. The Pantex internal dosimetry section monitors radiation workers once a month for tritium exposure. In order to manage collection and control of the bioassay specimens efficiently, a bar code system for collection of samples was developed and implemented to speed up the process and decrease the number of errors probable when transferring data. In the past, all the bioassay data from samples were entered manually into a computer database. Transferring the bioassay data from the liquid scintillation counter to each individual`s dosimetry record required as much as two weeks of concentrated effort.

  5. Estrogen Receptor Agonists and Antagonists in the Yeast Estrogen Bioassay.

    PubMed

    Wang, Si; Bovee, Toine F H

    2016-01-01

    Cell-based bioassays can be used to predict the eventual biological activity of a substance on a living organism. In vitro reporter gene bioassays are based on recombinant vertebrate cell lines or yeast strains and especially the latter are easy-to-handle, cheap, and fast. Moreover, yeast cells do not express estrogen, androgen, progesterone or glucocorticoid receptors, and are thus powerful tools in the development of specific reporter gene systems that are devoid of crosstalk from other hormone pathways. This chapter describes our experience with an in-house developed RIKILT yeast estrogen bioassay for testing estrogen receptor agonists and antagonists, focusing on the applicability of the latter. PMID:26585147

  6. Evaporation-Driven Bioassays in Suspended Droplets.

    PubMed

    Hernandez-Perez, Ruth; Fan, Z Hugh; Garcia-Cordero, Jose L

    2016-07-19

    The microtiter plate has been an essential tool for diagnostics, high-throughput screening, and biological assays. We present an alternative platform to perform bioassays in a microplate format that exploits evaporation to drive assay reactions. Our method consists of droplets suspended on plastic pillars; reactions occur in these droplets instead of the wells. The pillars are fabricated by milling, and the rough surface created by this fabrication method pins the droplet to a constant contact line during the assay and also acts as a hydrophobic surface. Upon evaporation, natural convection arising from Marangoni currents mixes solutions in the droplet, which speeds up assay reactions, decreases assay times, and increases limits of detection. As a proof of concept we implemented two colorimetric assays to detect glucose and proteins in only 1.5 μL, without any external devices for mixing and with a digital microscope as a readout mechanism. Our platform is an ideal alternative to the microtiter plate, works with different volumes, is compatible with commercially available reagent dispensers and plate-readers, and could have broad applications in diagnostics and high-throughput screening. PMID:27331825

  7. Annotating Human P-Glycoprotein Bioassay Data

    PubMed Central

    Zdrazil, Barbara; Pinto, Marta; Vasanthanathan, Poongavanam; Williams, Antony J; Balderud, Linda Zander; Engkvist, Ola; Chichester, Christine; Hersey, Anne; Overington, John P; Ecker, Gerhard F

    2012-01-01

    Abstract Huge amounts of small compound bioactivity data have been entering the public domain as a consequence of open innovation initiatives. It is now the time to carefully analyse existing bioassay data and give it a systematic structure. Our study aims to annotate prominent in vitro assays used for the determination of bioactivities of human P-glycoprotein inhibitors and substrates as they are represented in the ChEMBL and TP-search open source databases. Furthermore, the ability of data, determined in different assays, to be combined with each other is explored. As a result of this study, it is suggested that for inhibitors of human P-glycoprotein it is possible to combine data coming from the same assay type, if the cell lines used are also identical and the fluorescent or radiolabeled substrate have overlapping binding sites. In addition, it demonstrates that there is a need for larger chemical diverse datasets that have been measured in a panel of different assays. This would certainly alleviate the search for other inter-correlations between bioactivity data yielded by different assay setups. PMID:23293680

  8. K65R and K65A substitutions in HIV-1 reverse transcriptase enhance polymerase fidelity by decreasing both dNTP misinsertion and mispaired primer extension efficiencies

    PubMed Central

    Garforth, Scott J.; Domaoal, Robert A.; Lwatula, Chisanga; Landau, Mark J.; Meyer, Amanda J.; Anderson, Karen S.; Prasad, Vinayaka R.

    2010-01-01

    The Lys65 residue, in the fingers domain of HIV reverse transcriptase (RT), interacts in a sequence independent fashion with the incoming dNTP. Previously, we showed that a 5 amino acid deletion spanning Lys65 and a K65A substitution both enhanced the fidelity of dNTP insertion. We hypothesized that the Lys65 residue enhances dNTP misinsertion via interactions with the γ-phosphate of the incoming dNTP. We now examine this hypothesis in pre-steady state kinetic studies using wild type HIV-1 RT and two substitution mutants: K65A and K65R. The K65R mutation did not greatly increase misinsertion fidelity, but the K65A mutation led to higher incorporation fidelity. For a misinsertion to become a permanent error, it needs to be accompanied by the extension of the mispaired terminus thus formed. Both mutants, and the wild-type enzyme, discriminated against the mismatched primer at the catalytic step (kpol). Additionally, K65A and K65R mutants displayed a further decrease in mismatch extension efficiency, primarily at the level of dNTP binding. We employed hydroxyl radical footprinting to determine the position of the RT on the primer-template. The wild-type and Lys65 substituted enzymes occupied the same position at the primer terminus; the presence of a mismatched primer terminus caused all three enzymes to be displaced to a −2 position relative to the primer 3’ end. In the context of an efficiently extended mismatched terminus, the presence of the next complementary nucleotide overcame the displacement, resulting in a complex resembling the matched terminus. The results are consistent with the observed reduction in kpol in mispaired primer extension being due to the position of the enzyme at a mismatched terminus. Our work shows the influence of stabilizing interactions of Lys65 with the incoming dNTP in affecting two different aspects of polymerase fidelity. PMID:20538005

  9. Bioassay-Directed Fractionation of Diesel and Biodiesel Emissions

    EPA Science Inventory

    Biofuels are being developed as alternatives to petroleum-derived products, but published research is contradictory regarding the mutagenic activity of such emissions relative to those from petroleum diesel. We performed bioassay-directed fractionation and analyzed the polycyclic...

  10. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    SciTech Connect

    Dr. X. Geroge Xu

    2011-01-28

    A radiation bioassay program relies on a set of standard human phantoms to calibrate and assess radioactivity levels inside a human body for radiation protection and nuclear medicine imaging purposes. However, the methodologies in the development and application of anthropomorphic phantoms, both physical and computational, had mostly remained the same for the past 40 years. We herein propose a 3-year research project to develop medical image-based physical and computational phantoms specifically for radiation bioassay applications involving internally deposited radionuclides. The broad, long-term objective of this research was to set the foundation for a systematic paradigm shift away from the anatomically crude phantoms in existence today to realistic and ultimately individual-specific bioassay methodologies. This long-term objective is expected to impact all areas of radiation bioassay involving nuclear power plants, U.S. DOE laboratories, and nuclear medicine clinics.

  11. A CONTROLLED BIOASSAY SYSTEM FOR MEASURING TOXICITY OF HEAVY METALS

    EPA Science Inventory

    Biological availability of metal micronutrients and metal toxicity are believed to be dependent on metal oxidation state, complexation, and solubility as well as the physicochemical characteristics of the aqueous phase. Basic design criteria for fish bioassays which are capable o...

  12. A wind tunnel bioassay system for screening mosquito repellents.

    PubMed

    Sharpington, P J; Healy, T P; Copland, M J

    2000-09-01

    A wind tunnel bioassay system to screen mosquito repellents is described. A wind tunnel is utilized to exploit the upwind flight response of host-seeking mosquitoes. Mosquitoes within the wind tunnel are activated with human breath, fly upwind, and land on heated chick skins. This behavioral sequence results in a consistently high percentage of the test population approaching repellent or control stimuli. The bioassay system is calibrated with diethyl methylbenzamide against Aedes aegypti and demonstrates a reproducible dose-response relationship. The persistence of diethyl methyl benzamide after a 1-h period is also recorded. The design of the bioassay system permits simultaneous, independent testing of 3 candidate repellents. The wind tunnel bioassay system is compared to other techniques for evaluating mosquito repellents. PMID:11081652

  13. Comparison of laboratory batch and flow-through microcosm bioassays.

    PubMed

    Clément, Bernard J P; Delhaye, Hélène L; Triffault-Bouchet, Gaëlle G

    2014-10-01

    Since 1997, we have been developing a protocol for ecotoxicological bioassays in 2-L laboratory microcosms and have applied it to the study of various pollutants and ecotoxicological risk assessment scenarios in the area of urban facilities and transport infrastructures. The effects on five different organisms (micro-algae, duckweeds, daphnids, amphipods, chironomids) are assessed using biological responses such as growth, emergence (chironomids), reproduction (daphnids) and survival, with a duration of exposure of 3 weeks. This bioassay has mainly been used as a batch bioassay, i.e., the water was not renewed during the test. A flow-through microcosm bioassay has been developed recently, with the assumption that conditions for the biota should be improved, variability reduced, and the range of exposure patterns enlarged (e.g., the possibility of maintaining constant exposure in the water column). This paper compares the results obtained in batch and flow-through microcosm bioassays, using cadmium as a model toxicant. As expected, the stabilization of physico-chemical parameters, increased organism fitness and reduced variability were observed in the flow-through microcosm bioassay. PMID:25086825

  14. Comparison of Renal Amyloid and Hyaline Glomerulopathy in B6C3F1 Mice: An NTP Retrospective Study.

    PubMed

    Hoane, Jessica S; Johnson, Crystal L; Morrison, James P; Elmore, Susan A

    2016-07-01

    Due to potential misdiagnosis of hyaline glomerulopathy (HG) for amyloidosis, a retrospective study of B6C3F1 mice from the National Toxicology Program (NTP) archives was undertaken to determine whether HG had occurred in prior NTP studies and, if so, whether these 2 glomerular lesions could be routinely discriminated. Kidney slides from 7 amyloid-positive control mice, 2 HG-positive control mice, 3 normal or negative control mice, and 41 potential HG mice (with renal-only deposits previously diagnosed as amyloid) were evaluated using hematoxylin and eosin (H&E), periodic acid Schiff (PAS), Congo red (CR), and Masson's trichrome (MT) stains. Utilizing these techniques, HG was reliably distinguished from amyloidosis. All 41 potential HG mice had glomerular deposits histochemically inconsistent with amyloid; the deposits were PAS positive and CR negative. Four of the 41 mice were selected for transmission electron microscopy of the glomerular deposits; ultrastructurally, the deposits in these animals were consistent with HG and not amyloid. Our findings indicate that HG is a spontaneous lesion in B6C3F1 mice of low occurrence, is commonly misdiagnosed as amyloidosis, and is more likely than amyloid to cause glomerular deposits in mice without evidence of deposits in other tissues. Also, HG can be distinguished from amyloid on H&E evaluation; however, the distinction is improved with use of PAS or CR staining and/or ultraviolet evaluation. PMID:27000376

  15. Functional interplay between NTP leaving group and base pair recognition during RNA polymerase II nucleotide incorporation revealed by methylene substitution

    PubMed Central

    Hwang, Candy S.; Xu, Liang; Wang, Wei; Ulrich, Sébastien; Zhang, Lu; Chong, Jenny; Shin, Ji Hyun; Huang, Xuhui; Kool, Eric T.; McKenna, Charles E.; Wang, Dong

    2016-01-01

    RNA polymerase II (pol II) utilizes a complex interaction network to select and incorporate correct nucleoside triphosphate (NTP) substrates with high efficiency and fidelity. Our previous ‘synthetic nucleic acid substitution’ strategy has been successfully applied in dissecting the function of nucleic acid moieties in pol II transcription. However, how the triphosphate moiety of substrate influences the rate of P-O bond cleavage and formation during nucleotide incorporation is still unclear. Here, by employing β,γ-bridging atom-‘substituted’ NTPs, we elucidate how the methylene substitution in the pyrophosphate leaving group affects cognate and non-cognate nucleotide incorporation. Intriguingly, the effect of the β,γ-methylene substitution on the non-cognate UTP/dT scaffold (∼3-fold decrease in kpol) is significantly different from that of the cognate ATP/dT scaffold (∼130-fold decrease in kpol). Removal of the wobble hydrogen bonds in U:dT recovers a strong response to methylene substitution of UTP. Our kinetic and modeling studies are consistent with a unique altered transition state for bond formation and cleavage for UTP/dT incorporation compared with ATP/dT incorporation. Collectively, our data reveals the functional interplay between NTP triphosphate moiety and base pair hydrogen bonding recognition during nucleotide incorporation. PMID:27060150

  16. UV induced ubiquitination of the yeast Rad4-Rad23 complex promotes survival by regulating cellular dNTP pools.

    PubMed

    Zhou, Zheng; Humphryes, Neil; van Eijk, Patrick; Waters, Raymond; Yu, Shirong; Kraehenbuehl, Rolf; Hartsuiker, Edgar; Reed, Simon H

    2015-09-01

    Regulating gene expression programmes is a central facet of the DNA damage response. The Dun1 kinase protein controls expression of many DNA damage induced genes, including the ribonucleotide reductase genes, which regulate cellular dNTP pools. Using a combination of gene expression profiling and chromatin immunoprecipitation, we demonstrate that in the absence of DNA damage the yeast Rad4-Rad23 nucleotide excision repair complex binds to the promoters of certain DNA damage response genes including DUN1, inhibiting their expression. UV radiation promotes the loss of occupancy of the Rad4-Rad23 complex from the regulatory regions of these genes, enabling their induction and thereby controlling the production of dNTPs. We demonstrate that this regulatory mechanism, which is dependent on the ubiquitination of Rad4 by the GG-NER E3 ligase, promotes UV survival in yeast cells. These results support an unanticipated regulatory mechanism that integrates ubiquitination of NER DNA repair factors with the regulation of the transcriptional response controlling dNTP production and cellular survival after UV damage. PMID:26150418

  17. Highlights

    ERIC Educational Resources Information Center

    Mathematical Gazette, 1971

    1971-01-01

    Reprinted are "The Teaching of Euclid" by Bertrand Russell, an article on integrals by G. H. Hardy, "An Address on Relativity" by A. S. Eddington, "The Food of the Gods" by Prof. E. H. Neville, and "Simplicity and Truthfulness in Arithmetic" by W. Hope-Jones. (CT)

  18. Acarine attractants: Chemoreception, bioassay, chemistry and control.

    PubMed

    Carr, Ann L; Roe, Michael

    2016-07-01

    The Acari are of significant economic importance in crop production and human and animal health. Acaricides are essential for the control of these pests, but at the same time, the number of available pesticides is limited, especially for applications in animal production. The Acari consist of two major groups, the mites that demonstrate a wide variety of life strategies, i.e., herbivory, predation and ectoparasitism, and ticks which have evolved obligatory hematophagy. The major sites of chemoreception in the acarines are the chelicerae, palps and tarsi on the forelegs. A unifying name, the "foretarsal sensory organ" (FSO), is proposed for the first time in this review for the sensory site on the forelegs of all acarines. The FSO has multiple sensory functions including olfaction, gustation, and heat detection. Preliminary transcriptomic data in ticks suggest that chemoreception in the FSO is achieved by a different mechanism from insects. There are a variety of laboratory and field bioassay methods that have been developed for the identification and characterization of attractants but minimal techniques for electrophysiology studies. Over the past three to four decades, significant progress has been made in the chemistry and analysis of function for acarine attractants in mites and ticks. In mites, attractants include aggregation, immature female, female sex and alarm pheromones; in ticks, the attraction-aggregation-attachment, assembly and sex pheromones; in mites and ticks host kairomones and plant allomones; and in mites, fungal allomones. There are still large gaps in our knowledge of chemical communication in the acarines compared to insects, especially relative to acarine pheromones, and more so for mites than ticks. However, the use of lure-and-kill and lure-enhanced biocontrol strategies has been investigated for tick and mite control, respectively, with significant environmental advantages which warrant further study. PMID:27265828

  19. Nuclear Thermal Propulsion (NTP): A Proven, Growth Technology for Fast Transit Human Missions to Mars

    NASA Technical Reports Server (NTRS)

    Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

    2014-01-01

    The "fast conjunction" long surface stay mission option was selected for NASA's recent Mars Design Reference Architecture (DRA) 5.0 study because it provided adequate time at Mars (approx. 540 days) for the crew to explore the planet's geological diversity while also reducing the "1-way" transit times to and from Mars to approx. 6 months. Short transit times are desirable in order to reduce the debilitating physiological effects on the human body that can result from prolonged exposure to the zero-gravity (0-gE) and radiation environments of space. Recent measurements from the RAD detector attached to the Curiosity rover indicate that astronauts would receive a radiation dose of approx. 0.66 Sv (approx. 66 rem)-the limiting value established by NASA-during their 1-year journey in deep space. Proven nuclear thermal rocket (NTR) technology, with its high thrust and high specific impulse (Isp approx. 900 s), can cut 1-way transit times by as much as 50 percent by increasing the propellant capacity of the Mars transfer vehicle (MTV). No large technology scale-ups in engine size are required for these short transit missions either since the smallest engine tested during the Rover program-the 25 klbf "Pewee" engine is sufficient when used in a clustered arrangement of three to four engines. The "Copernicus" crewed MTV developed for DRA 5.0 is a 0-gE design consisting of three basic components: (1) the NTP stage (NTPS); (2) the crewed payload element; and (3) an integrated "saddle truss" and LH2 propellant drop tank assembly that connects the two elements. With a propellant capacity of approx. 190 t, Copernicus can support 1-way transit times ranging from approx. 150 to 220 days over the 15-year synodic cycle. The paper examines the impact on vehicle design of decreasing transit times for the 2033 mission opportunity. With a fourth "upgraded" SLS/HLV launch, an "in-line" LH2 tank element can be added to Copernicus allowing 1-way transit times of 130 days. To achieve 100

  20. NTP CENTER FOR THE EVALUATION OF RISKS TO HUMAN REPRODUCTION: PHTHALATES EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF DI-N-HEXYL PHTHALATE

    EPA Science Inventory

    The phthalates are a family of environmentally important compounds with diverse uses. Reproductive toxicity has been demonstrated for some members of this family. The NTP Center for the Evaluation of Risk to Human Reproduction (CERHR) convened an expert panel charged with examini...

  1. NTP CENTER FOR THE EVALUATION OF RISKS TO HUMAN REPRODUCTION: PHTHALATES EXPERT PANEL REPORT ON THE REPRODUCTIVE AND DEVELOPMENTAL TOXICITY OF BUTYL BENZYL PHTHALATE

    EPA Science Inventory

    The phthalates are a family of environmentally important compounds with diverse uses. Reproductive toxicity has been demonstrated for some members of this family. The NTP Center for the Evaluation of Risk to Human Reproduction (CERHR) convened an expert panel charged with examini...

  2. A security analysis of version 2 of the Network Time Protocol (NTP): A report to the privacy and security research group

    NASA Technical Reports Server (NTRS)

    Bishop, Matt

    1991-01-01

    The Network Time Protocol is being used throughout the Internet to provide an accurate time service. The security requirements are examined of such a service, version 2 of the NTP protocol is analyzed to determine how well it meets these requirements, and improvements are suggested where appropriate.

  3. Primary Bioassay of Human Myeloma Stem Cells

    PubMed Central

    Hamburger, Anne; Salmon, Sydney E.

    1977-01-01

    The ability to clone primary tumors in soft agar has proven useful in the study of the kinetics and biological properties of tumor stem cells. We report the development of an in vitro assay which permits formation of colonies of human monoclonal plasma cells in soft agar. Colony growth has been observed from bone marrow aspirates from 75% of the 70 patients with multiple myeloma or related monoclonal disorders studied. Growth was induced with either 0.02 ml of human type O erythrocytes or 0.25 ml of medium conditioned by the adherent spleen cells of mineral oil-primed BALB/c mice. 5-500 colonies appeared after 2-3 wk in culture yielding a plating efficiency of 0.001-0.1%. The number of myeloma colonies was proportional to the number of cells plated between concentrations of 105-106 and back-extrapolated through zero, suggesting that colonies were clones derived from single myeloma stem cells. Morphological, histochemical, and functional criteria showed the colonies to consist of immature plasmablasts and mature plasma cells. 60-80% of cells picked from colonies contained intracytoplasmic monoclonal immunoglobulin. Colony growth was most easily achieved from the bone marrow cells of untreated patients or those in relapse. Only 50% of bone marrow samples from patients in remission were successfully cultured. Tritiated thymidine suicide studies provided evidence that for most myeloma patients, a very high proportion of myeloma colony-forming cells was actively in transit through the cell cycle. Velocity sedimentation at 1 g showed myeloma stem cells sedimented in a broad band with a peak at 13 mm/h. Antibody to granulocyte colony-stimulating factor did not reduce the number or size of the colonies. Increased numbers of myeloma colonies were seen when the marrow was depleted of colony-stimulating factor elaborating adherent cells before plating. This bioassay should prove useful in studying the in vitro biological behavior of certain bone marrow-derived (B

  4. A novel laboratory screening bioassay for crop seedling allelopathy.

    PubMed

    Belz, Regina G; Hurle, Karl

    2004-01-01

    Crops that control weeds by root exudation of allelochemicals are receiving increased attention, and there are efforts to breed allelopathic cultivars in several crops. The genetic improvement of allelopathic traits is based upon parental germ plasm with high allelopathic activity. Identification of allelopathic germplasm is done in laboratory screening bioassays, but experimental protocols are limited. We developed a fast and reliable laboratory screening bioassay for grain crops that includes dose-response considerations as an integral part of the experimental design. The bioassay was conducted in hydroponic culture, and a range of experiments with 2-(3H)-benzoxazolinone (BOA), an allelochemical of several grain crops, was carried out to define the basic protocol. Because of its sensitivity to BOA, Sinapis alba L. was selected as the receiver species. BOA affected growth (fresh weight and length of shoot and root), enzyme activities (ascorbate peroxidase, catalase, glutathione S-transferase, peroxidase, phenylalanine ammonia-lyase), and chlorophyll fluorescence, whereby root length was the most reliable response parameter. BOA sensitivity was dependent on nutrients for all parameters measured, and, thus, no nutrients were added. A set of experiments with Secale cereale L. and Triticum aestivum L. as donor species was carried out to optimize the protocol. Light and pH were eliminated as primary causes for the observed inhibition. The proposed bioassay has several methodological advantages over current bioassays. PMID:15074665

  5. Soil bioassays and the {sup 129}I problem

    SciTech Connect

    Sheppard, S.C.

    1995-12-31

    Iodine-129 is a very long-lived radionuclide associated with spent nuclear fuel. Because {sup 129}I has a 10{sup 7}-year half-life, is very mobile in the environment and is a biologically essential element, it is the most limiting radionuclide affecting disposal of spent fuel. Traditionally, the potential impacts of {sup 129}I have been estimated for human receptors, with the implicit assumption that all other organisms are less at risk. Risk is the operative word, the objective for protection of humans is to protect individuals, whereas the objective for other biota is usually to protect populations. Here, {sup 129}I poses an interesting problem: the half-life is so long it is barely radioactive. Thus, the chemical toxicity may be more limiting than the radiological impact. A series of soil bioassays were employed, including a life-cycle plant (Brassica rapa) bioassay, a modified earthworm survival bioassay, a microarthropod colonization/survival bioassay, and a series of more common soil and aquatic bioassays. Chemical toxicity was indicated at soil concentrations as low as 5 mg kg{sup {minus}1}. At these levels, radiological impact on non-human biota would not be expected, and therefore the chemical toxicity effects are more critical. However, human food-chain model estimates show these levels, as pure {sup 129}I, would be unacceptable for human radiological exposure, so that for {sup 129}I, protection of the human environment should also be protective of non-human biota.

  6. [Investigation on pattern and methods of quality control for Chinese materia medica based on dao-di herbs and bioassay - bioassay for Coptis chinensis].

    PubMed

    Yan, Dan; Xiao, Xiao-he

    2011-05-01

    Establishment of bioassay methods is the technical issues to be faced with in the bioassay of Chinese materia medica. Taking the bioassay of Coptis chinensis Franch. as an example, the establishment process and application of the bioassay methods (including bio-potency and bio-activity fingerprint) were explained from the aspects of methodology, principle of selection, experimental design, method confirmation and data analysis. The common technologies were extracted and formed with the above aspects, so as to provide technical support for constructing pattern and method of the quality control for Chinese materia medica based on the dao-di herbs and bioassay. PMID:21800546

  7. Comparative activity of human carcinogens and NTP rodent carcinogens in the mouse bone marrow micronucleus assay: an integrative approach to genetic toxicity data assessment.

    PubMed Central

    Tinwell, H; Ashby, J

    1994-01-01

    The mouse bone marrow micronucleus (MN) assay holds a key position in all schemes for detecting potential human carcinogens and mutagens. It was therefore of concern when Shelby et al. reported that only 5 of 25 rodent carcinogens defined by the U.S. NTP were positive in the assay. Further, each of these positive responses was weak and indistinguishable from the 4 positive responses observed among the 24 NTP noncarcinogens tested. To focus these findings, the activity in the MN assay of 26 human carcinogens, 6 reference rodent genotoxins, and the 9 NTP chemicals positive in the MN assay have been displayed in a common format. This involved plotting the minimum positive dose level (expressed as mumole/kilogram) and the maximum fold-increase in micronucleated polychromatic erythrocytes frequency observed at any dose level. By displaying the high sensitivity of the micronucleus assay to the reference human and rodent genotoxins, this analysis emphasizes the weakness in the MN assay responses given by the NTP carcinogens reported by Shelby et al. This, in turn, poses questions about the intrinsic hazard of this selection of NTP rodent carcinogens. Using fotemustine and vitamin C as models of a toxic and a nontoxic chemical known to be active in the MN assay, this analysis describes a method by which their relative potential human hazard can be distinguished (a synthetic, as opposed to an analytical approach to data assessment). The possibility that some weak responses observed in the MN assay at elevated dose levels may be stress induced is considered. Images p758-a Figure 1. PMID:9657707

  8. GTP activator and dNTP substrates of HIV-1 restriction factor SAMHD1 generate a long-lived activated state

    PubMed Central

    Hansen, Erik C.; Seamon, Kyle J.; Cravens, Shannen L.; Stivers, James T.

    2014-01-01

    The HIV-1 restriction factor sterile α-motif/histidine-aspartate domain-containing protein 1 (SAMHD1) is a tetrameric protein that catalyzes the hydrolysis of all dNTPs to the deoxynucleoside and tripolyphosphate, which effectively depletes the dNTP substrates of HIV reverse transcriptase. Here, we establish that SAMHD1 is activated by GTP binding to guanine-specific activator sites (A1) as well as coactivation by substrate dNTP binding to a distinct set of nonspecific activator sites (A2). Combined activation by GTP and dNTPs results in a long-lived tetrameric form of SAMHD1 that persists for hours, even after activating nucleotides are withdrawn from the solution. These results reveal an ordered model for assembly of SAMHD1 tetramer from its inactive monomer and dimer forms, where GTP binding to the A1 sites generates dimer and dNTP binding to the A2 and catalytic sites generates active tetramer. Thus, cellular regulation of active SAMHD1 is not determined by GTP alone but instead, the levels of all dNTPs and the generation of a persistent tetramer that is not in equilibrium with free activators. The significance of the long-lived activated state is that SAMHD1 can remain active long after dNTP pools have been reduced to a level that would lead to inactivation. This property would be important in resting CD4+ T cells, where dNTP pools are reduced to nanomolar levels to restrict infection by HIV-1. PMID:24753578

  9. Atmospheric Research 2011 Technical Highlights

    NASA Technical Reports Server (NTRS)

    2012-01-01

    The 2011 Technical Highlights describes the efforts of all members of Atmospheric Research. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  10. Addressing the recovery of feeding rates in post-exposure feeding bioassays: Cyathura carinata as a case study

    SciTech Connect

    Pais-Costa, Antonia Juliana; Acevedo, Pelayo; Marques, João Carlos; Martinez-Haro, Mónica

    2015-02-15

    Post-exposure bioassays are used in environmental assessment as a cost-effective tool, but the effects of organism's recovery after exposure to pollutant has not yet been addressed in detail. The recoveries of post-exposure feeding rates after being exposed to two sublethal concentrations of cadmium during two different exposure periods (48 h and 96 h) were evaluated under laboratory conditions using the estuarine isopod Cyathura carinata. Results showed that feeding depression was a stable endpoint up to 24 h after cadmium exposure, which is useful for ecotoxicological bioassays. - Highlights: • We studied recovery of post-exposure feeding rates 48–96 h after cadmium exposure. • The assay is based on the isopod Cyathura carinata. • Post-exposure feeding inhibition is a stable sublethal endpoint.

  11. Environmental effects of dredging. A chronic sublethal sediment bioassay with the marine polychaete nereis (Neanthes) arenaceodentata

    SciTech Connect

    Dillon, T.M.; Moore, D.W.; Bridges, T.S.

    1995-01-01

    This note provides a general overview of a new 28-day chronic sublethal sediment bioassay designed for the regulatory evaluation of dredged material. The bioassay uses survival and growth rate endpoints with the polychaete Nereis (Neanthes) arenaceodentata. The primary technical reference for this new bioassay is Dillon, Moore, and Reish (in press), upon which this overview is based. Sediment bioassays are used to assess the aggregate toxicity of sediment associated anthropogenic chemicals. Historically, these bioassays have measured survival of highly sensitive species following acute exposures (10 days). A new generation of sediment bioassays is being developed in which the subtle, sublethal response of test species is measured following chronic sediment exposures (Dillon 1993).

  12. Carbon-14 Bioassay for Decommissioning of Hanford Reactors

    SciTech Connect

    Carbaugh, Eugene H.; Watson, David J.

    2012-05-01

    The old production reactors at the US Department of Energy Hanford Site used large graphite piles as the moderator. As part of long-term decommissioning plans, the potential need for 14C radiobioassay of workers was identified. Technical issues associated with 14C bioassay and worker monitoring were investigated, including anticipated graphite characterization, potential intake scenarios, and the bioassay capabilities that may be required to support the decommissioning of the graphite piles. A combination of urine and feces sampling would likely be required for the absorption type S 14C anticipated to be encountered. However the concentrations in the graphite piles appear to be sufficiently low that dosimetrically significant intakes of 14C are not credible, thus rendering moot the need for such bioassay.

  13. Method comparison for 241Am emergency urine bioassay.

    PubMed

    Li, Chunsheng; Sadi, Baki; Benkhedda, Karima; St-Amant, Nadereh; Moodie, Gerry; Ko, Raymond; Dinardo, Anthony; Kramer, Gary

    2010-10-01

    241Am is one of the high-risk radionuclides that might be used in a terrorist attack. 241Am in urine bioassay can identify the contaminated individuals who need immediate medical intervention and decontamination. This paper compares three methods for the measurement of 241Am in urine, namely liquid scintillation counting (LSC), inductively coupled plasma mass spectrometry (ICP-MS) and gamma spectrometry (GS), at two levels, 20 and 2 Bq l(-1). All three methods satisfied the ANSI N13.30 radio-bioassay criteria for accuracy and repeatability. ICP-MS offered the best sensitivity and fastest sample turnaround; however, the ICP-MS system used in this work may not be available in many bioassay laboratories. LSC and GS are more commonly available instruments. GS requires minimal or no sample preparation, which makes it a good candidate method. Moreover, the sample throughput can be significantly improved if the GS and LSC methods are automated. PMID:20573683

  14. Internal dosimetry performing dose assessments via bioassay measurements

    SciTech Connect

    Bailey, K.M.

    1993-05-11

    The Internal Dosimetry Department at the Y-12 Plant maintains a state-of-the-art bioassay program managed under the guidance and regulations of the Department of Energy. The two major bioassay techniques currently used at Y-12 are the in vitro (urinalysis) and in vivo (lung counting) programs. Fecal analysis (as part of the in vitro program) is another alternative; however, since both urine and fecal analysis provide essentially the same capabilities for detecting exposures to uranium, the urinalysis is the main choice primarily for aesthetic reasons. The bioassay frequency is based on meeting NCRP 87 objectives which are to monitor the accumulation of radioactive material in exposed individuals, and to ensure that significant depositions are detected.

  15. The effect of pesticide residue on caged mosquito bioassays.

    PubMed

    Barber, J A S; Greer, Mike; Coughlin, Jamie

    2006-09-01

    Wind tunnel experiments showed that secondary pickup of insecticide residue by mosquitoes in cage bioassays had a significant effect on mortality. Cage bioassays using adult Ochlerotatus taeniorhynchus (Wiedemann) investigated the effect of exposure time to a contaminated surface. Cages were dosed in a wind tunnel using the LC50 for naled (0.124 mg a.i./ml) and an LC25 (0.0772 mg a.i./ml) for naled. Half of the bioassay mosquitoes were moved directly into clean cages with the other half remaining in the sprayed, hence contaminated, cage. Treatment mortality was assessed at 8, 15, 30, 60, 120, 240, and 1,440 min postapplication. Cage contamination had a significant effect on mosquito mortality for both the LC25 and LC50 between 15 and 30 min postapplication. PMID:17067048

  16. Bioassay-directed chemical analysis in environmental research

    SciTech Connect

    Schuetzle, D.; Lewtas, J.

    1986-01-01

    The use of short-term bioassay tests in conjunction with analytical measurements, constitute a powerful tool for identifying important environmental contaminants. The authors have coined the terminology bioassay directed chemical analysis to best describe this marriage of analytical chemistry and biology. The objective of this methodology is to identify key compounds in various types of air-pollutant samples. Once that task is completed, studies on metabolism, sources, environmental exposure and atmospheric chemistry can be undertaken. The principles and methodologies for bioassay directed chemical analysis are presented and illustrated in this paper. Most of this work has been directed toward the characterization of ambient air and diesel particulates, which are used as examples in this report to illustrate the analytical logic used for identifying the bio-active components of complex mixtures.

  17. Do we really need in-situ bioassays?

    SciTech Connect

    Salazar, M.H.; Salazar, S.M.

    1995-12-31

    In-situ bioassays are needed to validate the results from laboratory testing and to understand biological interactions. Standard laboratory protocols provide reproducible test results, and the precision of those tests can be mathematically defined. Significant correlations between toxic substances and levels of response (bioaccumulation and bioeffects) have also been demonstrated with natural field populations and suggest that the laboratory results can accurately predict field responses. An equal number of studies have shown a lack of correlation between laboratory bioassay results and responses of natural field populations. The best way to validate laboratory results is with manipulative field testing; i.e., in-situ bioassays with caged organisms. Bioaccumulation in transplanted bivalves has probably been the most frequently used form of an in-situ bioassay. The authors have refined those methods to include synoptic measurements of bioaccumulation and growth. Growth provides an easily-measured bioeffects endpoint and a means of calibrating bioaccumulation. Emphasis has been on minimizing the size range of test animals, repetitive measurements of individuals and standardization of test protocols for a variety of applications. They are now attempting to standardize criteria for accepting and interpreting data in the same way that laboratory bioassays have been standardized. Others have developed methods for in-situ bioassays using eggs, larvae, unicellular organisms, crustaceans, benthic invertebrates, bivalves, and fish. In the final analysis, the in-situ approach could be considered as an exposure system where any clinical measurements are possible. The most powerful approach would be to use the same species in laboratory and field experiments with the same endpoints.

  18. LAMA Preconference and Program Highlights.

    ERIC Educational Resources Information Center

    Library Administration & Management, 1988

    1988-01-01

    Highlights events of the Library Administration and Management Association 1988 conference, including presentation of awards and programs on: (1) transfer of training; (2) hiring; (3) mentoring; (4) acquisitions automation; (5) library building consultation; and (6) managing shared systems. (MES)

  19. Johnson Space Center 2012 Highlights

    NASA Video Gallery

    The year has seen many highlights at NASA’s Johnson Space Center, Houston in the realm of human spaceflight exploration, international and commercial partnerships, and research and technology dev...

  20. Research and technology highlights, 1993

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This report contains highlights of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate both the broad range of the research and technology activities supported by NASA Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research. This report also describes some of the Center's most important research and testing facilities.

  1. Assessment of the environmental quality of coastal sediments by using a combination of in vitro bioassays.

    PubMed

    Pérez-Albaladejo, Elisabet; Rizzi, Juliane; Fernandes, Denise; Lille-Langøy, Roger; Karlsen, Odd André; Goksøyr, Anders; Oros, Andra; Spagnoli, Federico; Porte, Cinta

    2016-07-15

    The environmental quality of marine sediments collected in the area of influence of the Po and Danube Rivers was assessed by using a battery of bioassays based on the use of PLHC-1 cells, zebrafish-Pxr-transfected COS-7 cells, and sea bass ovarian subcellular fractions. This allowed the determination of multiple endpoints, namely, cytotoxicity, oxidative stress, induction of CYP1A, activation of zebrafish Pxr and inhibition of ovarian aromatase. Organic extracts of sediments influenced by the Danube River and collected near harbors and urban discharges showed significant cytotoxicity, CYP1A induction and inhibition of aromatase activity. An analogous response of CYP1A induction and zfPxr activation was observed, which suggests the existence of common ligands of AhR and PXR in the sediment extracts. The study highlights the usefulness of the selected bioassays to identify those sediments that could pose a risk to aquatic organisms and that require further action in order to improve their environmental quality. PMID:27207027

  2. A statistical treatment of bioassay pour fractions

    NASA Astrophysics Data System (ADS)

    Barengoltz, Jack; Hughes, David

    A bioassay is a method for estimating the number of bacterial spores on a spacecraft surface for the purpose of demonstrating compliance with planetary protection (PP) requirements (Ref. 1). The details of the process may be seen in the appropriate PP document (e.g., for NASA, Ref. 2). In general, the surface is mechanically sampled with a damp sterile swab or wipe. The completion of the process is colony formation in a growth medium in a plate (Petri dish); the colonies are counted. Consider a set of samples from randomly selected, known areas of one spacecraft surface, for simplicity. One may calculate the mean and standard deviation of the bioburden density, which is the ratio of counts to area sampled. The standard deviation represents an estimate of the variation from place to place of the true bioburden density commingled with the precision of the individual sample counts. The accuracy of individual sample results depends on the equipment used, the collection method, and the culturing method. One aspect that greatly influences the result is the pour fraction, which is the quantity of fluid added to the plates divided by the total fluid used in extracting spores from the sampling equipment. In an analysis of a single sample’s counts due to the pour fraction, one seeks to answer the question: What is the probability that if a certain number of spores are counted with a known pour fraction, that there are an additional number of spores in the part of the rinse not poured. This is given for specific values by the binomial distribution density, where detection (of culturable spores) is success and the probability of success is the pour fraction. A special summation over the binomial distribution, equivalent to adding for all possible values of the true total number of spores, is performed. This distribution when normalized will almost yield the desired quantity. It is the probability that the additional number of spores does not exceed a certain value. Of course

  3. A statistical treatment of bioassay pour fractions

    NASA Astrophysics Data System (ADS)

    Barengoltz, Jack; Hughes, David

    A bioassay is a method for estimating the number of bacterial spores on a spacecraft surface for the purpose of demonstrating compliance with planetary protection (PP) requirements (Ref. 1). The details of the process may be seen in the appropriate PP document (e.g., for NASA, Ref. 2). In general, the surface is mechanically sampled with a damp sterile swab or wipe. The completion of the process is colony formation in a growth medium in a plate (Petri dish); the colonies are counted. Consider a set of samples from randomly selected, known areas of one spacecraft surface, for simplicity. One may calculate the mean and standard deviation of the bioburden density, which is the ratio of counts to area sampled. The standard deviation represents an estimate of the variation from place to place of the true bioburden density commingled with the precision of the individual sample counts. The accuracy of individual sample results depends on the equipment used, the collection method, and the culturing method. One aspect that greatly influences the result is the pour fraction, which is the quantity of fluid added to the plates divided by the total fluid used in extracting spores from the sampling equipment. In an analysis of a single sample’s counts due to the pour fraction, one seeks to answer the question: What is the probability that if a certain number of spores are counted with a known pour fraction, that there are an additional number of spores in the part of the rinse not poured. This is given for specific values by the binomial distribution density, where detection (of culturable spores) is success and the probability of success is the pour fraction. A special summation over the binomial distribution, equivalent to adding for all possible values of the true total number of spores, is performed. This distribution when normalized will almost yield the desired quantity. It is the probability that the additional number of spores does not exceed a certain value. Of course

  4. HIGHLY SENSITIVE BIOASSAYS FOR EVALUATING AIRBORNE MUTAGENS INDOORS

    EPA Science Inventory

    The standard mutagenicity bioassays that are readily applied to the valuation of outdoor air samples collected by high volume samplers are not efficiently sensitive to measure the mutagenicity of low volume air samples collected indoors. wo microsuspension mutation assays using v...

  5. Filtration effects due to bioassay cage design and screen type

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of bioassay cages in the efficacy assessment of specific compounds, application techniques and technologies is a common practice. There are a number of cage designs being used that range across a variety of cage shapes and sizes and mesh types. The objective of this work was to examine a r...

  6. STRESS ETHYLENE: A BIOASSAY FOR RHIZOSPHERE-APPLIED PHYTOTOXICANTS

    EPA Science Inventory

    A bioassay for rhizosphere-applied phytotoxicants was developed and evaluated with a broad range of chemicals. Test substances were applied to the rhizosphere of whole, intact bush bean plants (Phaseolus vulgaris L. cv. Bush Blue Lake 290) grown in a solid support medium and the ...

  7. Assessment of acrylamide toxicity using a battery of standardised bioassays.

    PubMed

    Zovko, Mira; Vidaković-Cifrek, Željka; Cvetković, Želimira; Bošnir, Jasna; Šikić, Sandra

    2015-12-01

    Acrylamide is a monomer widely used as an intermediate in the production of organic chemicals, e.g. polyacrylamides (PAMs). Since PAMs are low cost chemicals with applications in various industries and waste- and drinking water treatment, a certain amount of non-polymerised acrylamide is expected to end up in waterways. PAMs are non-toxic but acrylamide induces neurotoxic effects in humans and genotoxic, reproductive, and carcinogenic effects in laboratory animals. In order to evaluate the effect of acrylamide on freshwater organisms, bioassays were conducted on four species: algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata, duckweed Lemna minor and water flea Daphnia magna according to ISO (International Organization for Standardisation) standardised methods. This approach ensures the evaluation of acrylamide toxicity on organisms with different levels of organisation and the comparability of results, and it examines the value of using a battery of low-cost standardised bioassays in the monitoring of pollution and contamination of aquatic ecosystems. These results showed that EC50 values were lower for Desmodesmus subspicatus and Pseudokirchneriella subcapitata than for Daphnia magna and Lemna minor, which suggests an increased sensitivity of algae to acrylamide. According to the toxic unit approach, the values estimated by the Lemna minor and Daphnia magna bioassays, classify acrylamide as slightly toxic (TU=0-1; Class 1). The results obtained from algal bioassays (Desmodesmus subspicatus and Pseudokirchneriella subcapitata) revealed the toxic effect of acrylamide (TU=1-10; Class 2) on these organisms. PMID:26751864

  8. Artificial diets for life tables bioassays of TPB in Mississippi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two artificial diets for mass rearing and bioassay of the tarnished plant bug, (TPB), Lygus lineolaris Palisot de Beauvois, (Hemiptera: Miridae) were modified and developed, respectively. The first diet is a modification of a semisolid artificial diet (NI diet), which permits large scale rearing of ...

  9. INFLUENCE OF SEDIMENT EXTRACT FRACTIONATION METHODS ON BIOASSAY RESULTS

    EPA Science Inventory

    Four bioassays [Microtax(tm), Mutatox(tm), sister chromatid exchange (SCE), and metabolic cooperation] were used to analyze marine sediment extracts fractionated by two different methods: silica gel column chromatography and acid-base fractionation. esults indicated that a sedime...

  10. Statistical considerations in the analysis of data from replicated bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multiple-dose bioassay is generally the preferred method for characterizing virulence of insect pathogens. Linear regression of probit mortality on log dose enables estimation of LD50/LC50 and slope, the latter having substantial effect on LD90/95s (doses of considerable interest in pest management)...

  11. Soil bioassays as tools for sludge compost quality assessment

    SciTech Connect

    Domene, Xavier; Sola, Laura; Ramirez, Wilson; Alcaniz, Josep M.; Andres, Pilar

    2011-03-15

    Composting is a waste management technology that is becoming more widespread as a response to the increasing production of sewage sludge and the pressure for its reuse in soil. In this study, different bioassays (plant germination, earthworm survival, biomass and reproduction, and collembolan survival and reproduction) were assessed for their usefulness in the compost quality assessment. Compost samples, from two different composting plants, were taken along the composting process, which were characterized and submitted to bioassays (plant germination and collembolan and earthworm performance). Results from our study indicate that the noxious effects of some of the compost samples observed in bioassays are related to the low organic matter stability of composts and the enhanced release of decomposition endproducts, with the exception of earthworms, which are favored. Plant germination and collembolan reproduction inhibition was generally associated with uncomposted sludge, while earthworm total biomass and reproduction were enhanced by these materials. On the other hand, earthworm and collembolan survival were unaffected by the degree of composting of the wastes. However, this pattern was clear in one of the composting procedures assessed, but less in the other, where the release of decomposition endproducts was lower due to its higher stability, indicating the sensitivity and usefulness of bioassays for the quality assessment of composts.

  12. US Army Radiological Bioassay and Dosimetry: The RBD software package

    SciTech Connect

    Eckerman, K. F.; Ward, R. C.; Maddox, L. B.

    1993-01-01

    The RBD (Radiological Bioassay and Dosimetry) software package was developed for the U. S. Army Material Command, Arlington, Virginia, to demonstrate compliance with the radiation protection guidance 10 CFR Part 20 (ref. 1). Designed to be run interactively on an IBM-compatible personal computer, RBD consists of a data base module to manage bioassay data and a computational module that incorporates algorithms for estimating radionuclide intake from either acute or chronic exposures based on measurement of the worker's rate of excretion of the radionuclide or the retained activity in the body. In estimating the intake,RBD uses a separate file for each radionuclide containing parametric representations of the retention and excretion functions. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent. For a given nuclide, if measurements exist for more than one type of assay, an auxiliary module, REPORT, estimates the intake by applying weights assigned in the nuclide file for each assay. Bioassay data and computed results (estimates of intake and committed dose equivalent) are stored in separate data bases, and the bioassay measurements used to compute a given result can be identified. The REPORT module creates a file containing committed effective dose equivalent for each individual that can be combined with the individual's external exposure.

  13. Book Review: Bioassays with Arthropods: 2nd Edition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The technical book "Bioassays with Arthropods: 2nd Edition" (2007. Jacqueline L. Robertson, Robert M. Russell, Haiganoush K, Preisler and N. E. Nevin, Eds. CRC Press, Boca Raton, FL, 224 pp.) was reviewed for the scientific readership of the peer-reviewed publication Journal of Economic Entomology. ...

  14. US Army Radiological Bioassay and Dosimetry: The RBD software package

    SciTech Connect

    Eckerman, K.F.; Ward, R.C.; Maddox, L.B.

    1993-01-01

    The RBD (Radiological Bioassay and Dosimetry) software package was developed for the U. S. Army Material Command, Arlington, Virginia, to demonstrate compliance with the radiation protection guidance 10 CFR Part 20 (ref. 1). Designed to be run interactively on an IBM-compatible personal computer, RBD consists of a data base module to manage bioassay data and a computational module that incorporates algorithms for estimating radionuclide intake from either acute or chronic exposures based on measurement of the worker`s rate of excretion of the radionuclide or the retained activity in the body. In estimating the intake,RBD uses a separate file for each radionuclide containing parametric representations of the retention and excretion functions. These files also contain dose-per-unit-intake coefficients used to compute the committed dose equivalent. For a given nuclide, if measurements exist for more than one type of assay, an auxiliary module, REPORT, estimates the intake by applying weights assigned in the nuclide file for each assay. Bioassay data and computed results (estimates of intake and committed dose equivalent) are stored in separate data bases, and the bioassay measurements used to compute a given result can be identified. The REPORT module creates a file containing committed effective dose equivalent for each individual that can be combined with the individual`s external exposure.

  15. BENTHIC INVERTEBRATE BIOASSAYS WITH TOXIC SEDIMENT AND PORE WATER

    EPA Science Inventory

    The relative sensitivities of bioassays to determine the toxicity of sediments were investigated and three methods of making the sample dilutions required to generate dose-response relationships were compared. he assays studied were: (a) Microtox, a 15-min assay of Photobacterium...

  16. Shape-encoded silica microparticles for multiplexed bioassays.

    PubMed

    Kim, Lily Nari; Kim, Mira; Jung, Keumsim; Bae, Hyung Jong; Jang, Jisung; Jung, Yushin; Kim, Jiyun; Kwon, Sunghoon

    2015-08-01

    Shape-encoded silica microparticles for use in multiplexed bioassays were fabricated by using optofluidic maskless lithography (OFML) and tetraethylorthosilicate (TEOS) polymerization. These encoded silica microparticles exhibit excellent bioconjugation properties and negligible non-specific analyte adsorption. Encoded silica microparticles could be useful in a wide variety of applications, including DNA- and protein-based diagnostics. PMID:26125980

  17. Microplate Bioassay for Determining Substrate Selectivity of "Candida rugosa" Lipase

    ERIC Educational Resources Information Center

    Wang, Shi-zhen; Fang, Bai-shan

    2012-01-01

    Substrate selectivity of "Candida rugosa" lipase was tested using "p"-nitrophenyl esters of increasing chain length (C[subscript 1], C[subscript 7], C[subscript 15]) using the high-throughput screening method. A fast and easy 96-well microplate bioassay was developed to help students learn and practice biotechnological specificity screen. The…

  18. Correction of spray concentration and bioassay cage penetration data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field trials were conducted to demonstrate the need for correcting sampled spray concentration data for sampler collection efficiencies and estimated spray exposure levels in mosquito bioassays for cage interference effects. A large spray block was targeted with aerial spray treatments of etofenpro...

  19. 1. VIEW IN ROOM 125, BIOASSAY LABORATORY, SHOWN IS THE ...

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

    1. VIEW IN ROOM 125, BIOASSAY LABORATORY, SHOWN IS THE FIRST STEP IN A SIX-STEP PROCESS TO ANALYZE URINE SAMPLES FOR PLUTONIUM AND URANIUM CONTAMINATION. IN THIS STEP, NITRIC ACID IS ADDED TO SAMPLE, AND THE SAMPLE IS BOILED DOWN TO A WHITE POWDER. - Rocky Flats Plant, Health Physics Laboratory, On Central Avenue between Third & Fourth Streets, Golden, Jefferson County, CO

  20. Medium-term bioassays for carcinogenicity of chemical mixtures.

    PubMed Central

    Ito, N; Imaida, K; Hirose, M; Shirai, T

    1998-01-01

    Carcinogenic effects of chemical mixtures were examined with a medium-term liver bioassay for carcinogens or a multiorgan medium-term bioassay using male F344 rats. In the medium-term liver bioassay, rats were initially treated with diethylnitrosamine (DEN) at 200 mg/kg body weight, i.p.; after 2 weeks they received chemical mixtures such as 10 different heterocyclic amines at one-tenth or one-hundredth the dose levels used in carcinogenicity studies and the mixtures of 20 different pesticides, each at acceptable daily intake (ADI) levels or a mixture of 100 times ADI levels. All animals were subjected to two-thirds partial hepatectomy at week 3 and were sacrificed at week 8. The number and areas of glutathione S-transferase placental form (GST-P) positive foci (preneoplastic lesions in the liver) were compared between respective groups. When 10 heterocyclic amines were mixed in the diet at one-tenth dose level, clear synergism was observed, but no combined effects were evident with the one-hundredth dose levels. In the pesticide experiment, treatment of rats with the 20-pesticide mixture at the ADI dose level did not enhance GST-P-positive foci. In contrast, a mixture of 100 times the ADI significantly increased those values. In a multiorgan bioassay of 28 weeks, mixtures of 40 high-volume compounds and 20 pesticides (suspected carcinogens) added together at their respective ADI levels did not enhance carcinogenesis in any organs initiated by five different carcinogens (DEN, N-methylnitrosourea, dimethylhydrazine, N-butyl-N-(4-hydroxybutyl)nitrosamine, and dihydroxy-di-n-propylnitrosamine) in combination. The combination effect of low dietary levels of five antioxidants, butylated hydroxyanisole, caffeic acid, sesamol, 4-methoxyphenol, and catechol, were also examined using the multiorgan bioassay. The incidence of forestomach papillomas was significantly increased only in the combination group and the results indicate that combination of the five antioxidants can

  1. Genotoxicity of leachates from a landfill using three bioassays.

    PubMed

    Cabrera, G L; Rodriguez, D M

    1999-05-19

    In the city of Queretaro, around 500 tons of solid wastes are produced everyday and are deposited in a landfill. This is the result of social and economic activities of human beings or from their normal physiological functions. As a result of rain, leachates are produced, which, if not handled and treated correctly, may pollute the underground water. Among the bioassays developed for the detection of mutagenicity in environmental pollutants, plant systems have been proven to be sensitive, cheap, and effective. The purpose of this study was to determine the presence of genotoxic agents in the leachates of the landfill of the city using three bioassays: Tradescantia-micronucleus (Trad-MCN), Tradescantia stamen hair mutations (Trad-SHM) and Allium root anaphase aberrations (AL-RAA) and make a comparison of the results in the three assays. Leachates were sampled during both the dry and rainy seasons. Plant cuttings of Tradescantia or the roots of Allium were treated by submerging them in the leachates. Three replicates of each sample were analyzed in each of the three bioassays. As expected the samples of leachates collected during the dry season showed a higher genotoxicity than those collected during the rainy season. In conclusion, there are substances present in the leachates capable of inducing genotoxicity in the plant assays. On the other hand, the plant assays showed different degrees of sensitivity: the more sensitive was the Trad-MCN bioassay and the less sensitive the Trad-SHM assay. Therefore, when analyzing environmental pollutants it is recommended to use a battery of bioassays. PMID:10350599

  2. Evaluation of genotoxic effects caused by extracts of chlorinated drinking water using a combination of three different bioassays.

    PubMed

    Zeng, Qiang; Zhang, Shao-Hui; Liao, Jing; Miao, Dong-Yue; Wang, Xin-Yi; Yang, Pan; Yun, Luo-Jia; Liu, Ai-Lin; Lu, Wen-Qing

    2015-10-15

    Potential genotoxic effects of chlorinated drinking water now are of a great concern. In this study, raw water, finished water, and tap water from a water plant in Wuhan, China were collected in two different sampling times of the year (January and July). Genotoxic effects of water extracts were evaluated using a combination of three different bioassays: SOS/umu test, HGPRT gene mutation assay, and micronucleus assay, which were separately used to detect DNA damage, gene mutation, and chromosome aberration. The results of three different bioassays showed that all water samples in January and July induced at least one types of genotoxic effects, of which the DNA-damage effects were all detectable. The levels of DNA-damage effects and gene-mutation effects of finished water and tap water in January were higher than those in July. Chlorination could increase the DNA-damage effects of drinking water in January and the gene-mutation effects of drinking water in both January and July, but did not increase the chromosome-aberration effects of drinking water in both January and July. Our results highlighted the importance of using a combination of different bioassays to evaluate the genotoxicity of water samples in different seasons. PMID:25910456

  3. ASTD's 1974 Conference--Highlights

    ERIC Educational Resources Information Center

    Training and Development Journal, 1974

    1974-01-01

    Highlights of speeches presented at the 30th ASTD National Conference in San Francisco are given: S.I. Hayakawa outlined developments in higher education during the 1970's; Joe Batten called for life enrichment, not just job enrichment; and Dorothy Jongeward discussed transactional analysis as a tool for more effective interpersonal relationships.…

  4. Kinetics of muscle contraction and actomyosin NTP hydrolysis from rabbit using a series of metal–nucleotide substrates

    PubMed Central

    Burton, Kevin; White, Howard; Sleep, John

    2005-01-01

    Mechanical properties of skinned single fibres from rabbit psoas muscle have been correlated with biochemical steps in the cross-bridge cycle using a series of metal–nucleotide (Me·NTP) substrates (Mn2+ or Ni2+ substituted for Mg2+; CTP or ITP for ATP) and inorganic phosphate. Measurements were made of the rate of force redevelopment following (1) slack tests in which force recovery followed a period of unloaded shortening, or (2) ramp shortening at low load terminated by a rapid restretch. The form and rate of force recovery were described as the sum of two exponential functions. Actomyosin-Subfragment 1 (acto-S1) Me·NTPase activity and Me·NDP release were monitored under the same conditions as the fibre experiments. Mn·ATP and Mg·CTP both supported contraction well and maintained good striation order. Relative to Mg·ATP, they increased the rates and Me·NTPase activity of cross-linked acto-S1 and the fast component of a double-exponential fit to force recovery by ∼50% and 10–35%, respectively, while shortening velocity was moderately reduced (by 20–30%). Phosphate also increased the rate of the fast component of force recovery. In contrast to Mn2+ and CTP, Ni·ATP and Mg·ITP did not support contraction well and caused striations to become disordered. The rates of force recovery and Me·NTPase activity were less than for Mg·ATP (by 40–80% and 50–85%, respectively), while shortening velocity was greatly reduced (by ∼80%). Dissociation of ADP from acto-S1 was little affected by Ni2+, suggesting that Ni·ADP dissociation does not account for the large reduction in shortening velocity. The different effects of Ni2+ and Mn2+ were also observed during brief activations elicited by photolytic release of ATP. These results confirm that at least one rate-limiting step is shared by acto-S1 ATPase activity and force development. Our results are consistent with a dual rate-limitation model in which the rate of force recovery is limited by both NTP

  5. Mechanism of NTP Hydrolysis by the Escherichia coli Primary Replicative Helicase DnaB Protein. 2. Nucleotide and Nucleic Acid Specificities†

    PubMed Central

    Roychowdhury, Anasuya; Szymanski, Michal R.; Jezewska, Maria J.; Bujalowski, Wlodzimierz

    2011-01-01

    The kinetic mechanism of NTP binding and hydrolysis by the Escherichia coli replicative helicase, the DnaB protein, in the absence and presence of the single-stranded DNA (ssDNA), has been quantitatively examined using the rapid quench-flow technique, under single-turnover conditions. In the case of both the free helicase and the enzyme–ssDNA complexes, the mechanism is independent of the type of base of the cofactor or the DNA; the bimolecular association is followed by the reversible chemical hydrolysis and subsequent conformational transition of the enzyme–product complex. The NTP hydrolysis step is significantly faster for the purine than for the pyrimidine cofactor, both in the absence and in the presence of the DNA. The temperature effect indicates that the nature of intermediates of the purine nucleotide, ATP, is different from the nature of the analogous intermediates of the pyrimidine nucleotide, CTP. Nevertheless, both types of cofactors seem to approach a similar “exit” state at the end of the reaction. The effect of ssDNA on the kinetics of NTP hydrolysis depends on the type of nucleotide cofactor and the base composition of the DNA and is centered at the hydrolysis step. Homoadenosine ssDNA oligomers are particularly effective in increasing the hydrolysis rate. The allosteric signal from the DNA, which activates the NTP hydrolysis, comes predominantly from the strong DNA-binding subsite. The role of the weak DNA-binding subsite is to modulate the allosteric effect of the strong subsite. The significance of these results for the mechanism of the free energy transduction by the DnaB helicase is discussed. PMID:19435286

  6. BioAssay Ontology (BAO): a semantic description of bioassays and high-throughput screening results

    PubMed Central

    2011-01-01

    Background High-throughput screening (HTS) is one of the main strategies to identify novel entry points for the development of small molecule chemical probes and drugs and is now commonly accessible to public sector research. Large amounts of data generated in HTS campaigns are submitted to public repositories such as PubChem, which is growing at an exponential rate. The diversity and quantity of available HTS assays and screening results pose enormous challenges to organizing, standardizing, integrating, and analyzing the datasets and thus to maximize the scientific and ultimately the public health impact of the huge investments made to implement public sector HTS capabilities. Novel approaches to organize, standardize and access HTS data are required to address these challenges. Results We developed the first ontology to describe HTS experiments and screening results using expressive description logic. The BioAssay Ontology (BAO) serves as a foundation for the standardization of HTS assays and data and as a semantic knowledge model. In this paper we show important examples of formalizing HTS domain knowledge and we point out the advantages of this approach. The ontology is available online at the NCBO bioportal http://bioportal.bioontology.org/ontologies/44531. Conclusions After a large manual curation effort, we loaded BAO-mapped data triples into a RDF database store and used a reasoner in several case studies to demonstrate the benefits of formalized domain knowledge representation in BAO. The examples illustrate semantic querying capabilities where BAO enables the retrieval of inferred search results that are relevant to a given query, but are not explicitly defined. BAO thus opens new functionality for annotating, querying, and analyzing HTS datasets and the potential for discovering new knowledge by means of inference. PMID:21702939

  7. Incorporation of deoxyribonucleotides and ribonucleotides by a dNTP-binding cleft mutated reverse transcriptase in hepatitis B virus core particles

    SciTech Connect

    Kim, Hee-Young; Kim, Hye-Young; Jung, Jaesung; Park, Sun; Shin, Ho-Joon; Kim, Kyongmin

    2008-01-05

    Our recent observation that hepatitis B virus (HBV) DNA polymerase (P) might initiate minus-strand DNA synthesis without primer [Kim et al., (2004) Virology 322, 22-30], raised a possibility that HBV P protein may have the potential to function as an RNA polymerase. Thus, we mutated Phe 436, a bulky amino acid with aromatic side chain, at the putative dNTP-binding cleft in reverse transcriptase (RT) domain of P protein to smaller amino acids (Gly or Val), and examined RNA polymerase activity. HBV core particles containing RT dNTP-binding cleft mutant P protein were able to incorporate {sup 32}P-ribonucleotides, but not HBV core particles containing wild type (wt), priming-deficient mutant, or RT-deficient mutant P proteins. Since all the experiments were conducted with core particles isolated from transfected cells, our results indicate that the HBV RT mutant core particles containing RT dNTP-binding cleft mutant P protein could incorporate both deoxyribonucleotides and ribonucleotides in replicating systems.

  8. Research and technology highlights, 1992

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The mission of the NASA Langley Research Center is to increase the knowledge and capability of the United States in a full range of aeronautics disciplines and in selected space disciplines. This mission will be accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government agencies, industry, and other NASA centers. Highlights of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year are presented. The highlights illustrate both the broad range of research and technology (R&T) activities supported by NASA Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research. Some of the Center's most important research and testing facilities are also described.

  9. Langley aerospace test highlights, 1990

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The role of NASA-Langley is to perform basic and applied research necessary for the advancement of aeronautics and spaceflight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests are highlighted which were performed during 1990 in the NASA-Langley test facilities, a number of which are unique in the world. Both the broad range of the research and technology activities at NASA-Langley and the contributions of this work toward maintaining U.S. leadership in aeronautics and space research are illustrated. Other highlights of Langley research and technology for 1990 are described in Research and Technology 1990 Langley Research Center.

  10. CEAS-ASC highlights 2006

    NASA Astrophysics Data System (ADS)

    Caro, Stéphane

    2007-07-01

    The Council of European Aerospace Societies (CEAS) Aeroacoustics Specialists Committee (ASC) supports and promotes the interests of the scientific and industrial aeroacoustics community on a European scale and European aeronautics activities internationally. In this context, "aeroacoustics" encompasses all aerospace acoustics and related areas. Each year the committee highlights some of the research and development projects in Europe. This paper is a report on some highlights of aeroacoustics research in Europe in 2006, compiled from information provided to the ASC of the CEAS. During 2006, numerous research programmes were funded by the European Union. Some of the contributions submitted to the editor summarize selected findings from these programmes, while other articles cover issues supported by national associations. Furthermore, a concise summary of the workshop on "Aeroacoustics of Jet Noise" held in Dublin in September is included in this report. Enquiries concerning all contributions should be addressed to the authors who are given at the end of each subsection.

  11. Langley aerospace test highlights, 1985

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Significant tests which were performed during calendar year 1985 in Langley test facilities, are highlighted. Both the broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research, are illustrated. Other highlights of Langley research and technology for 1985 are described in Research and Technology-1985 Annual Report of the Langley Research Center.

  12. Langley aerospace test highlights, 1989

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The role of the NASA Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and spaceflight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests that were performed during calendar year 1989 in the NASA Langley Research Center test facilities are highlighted. Both the broad range of the research and technology activities at the NASA Langley Research Center are illustrated along with the contributions of this work toward maintaining United States leadership in aeronautics and space research. Other highlights of Langley research and technology for 1989 are described in Research and Technology 1989 - Langley Research Center.

  13. Tourette syndrome research highlights 2015

    PubMed Central

    Richards, Cheryl A.; Black, Kevin J.

    2016-01-01

    We present selected highlights from research that appeared during 2015 on Tourette syndrome and other tic disorders. Topics include phenomenology, comorbidities, developmental course, genetics, animal models, neuroimaging, electrophysiology, pharmacology, and treatment. We briefly summarize articles whose results we believe may lead to new treatments, additional research or modifications in current models of TS. PMID:27429744

  14. Highlights of Spanish Astrophysics VII

    NASA Astrophysics Data System (ADS)

    Guirado, J. C.; Lara, L. M.; Quilis, V.; Gorgas, J.

    2013-05-01

    "Highlights of Astronomy and Astrophysics VII" contains the Proceedings of the biannual meeting of the Spanish Astronomical Society held in Valencia from July 9 to 13, 2012. Over 300 astronomer, both national and international researchers, attended to the conference covering a wide variety of astrophysical topics: Galaxies and Cosmology, The Milky Way and Its Components, Planetary Sciences, Solar Physics, Instrumentation and Computation, and Teaching and Outreach of Astronomy.

  15. Research and Technology Highlights 1995

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The mission of the NASA Langley Research Center is to increase the knowledge and capability of the United States in a full range of aeronautics disciplines and in selected space disciplines. This mission is accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government agencies, industry, other NASA Centers, the educational community, and the local community. This report contains highlights of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate both the broad range of research and technology (R&T) activities carried out by NASA Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research. An electronic version of the report is available at URL http://techreports.larc.nasa.gov/RandT95. This color version allows viewing, retrieving, and printing of the highlights, searching and browsing through the sections, and access to an on-line directory of Langley researchers.

  16. Inhibiting WEE1 Selectively Kills Histone H3K36me3-Deficient Cancers by dNTP Starvation.

    PubMed

    Pfister, Sophia X; Markkanen, Enni; Jiang, Yanyan; Sarkar, Sovan; Woodcock, Mick; Orlando, Giulia; Mavrommati, Ioanna; Pai, Chen-Chun; Zalmas, Lykourgos-Panagiotis; Drobnitzky, Neele; Dianov, Grigory L; Verrill, Clare; Macaulay, Valentine M; Ying, Songmin; La Thangue, Nicholas B; D'Angiolella, Vincenzo; Ryan, Anderson J; Humphrey, Timothy C

    2015-11-01

    Histone H3K36 trimethylation (H3K36me3) is frequently lost in multiple cancer types, identifying it as an important therapeutic target. Here we identify a synthetic lethal interaction in which H3K36me3-deficient cancers are acutely sensitive to WEE1 inhibition. We show that RRM2, a ribonucleotide reductase subunit, is the target of this synthetic lethal interaction. RRM2 is regulated by two pathways here: first, H3K36me3 facilitates RRM2 expression through transcription initiation factor recruitment; second, WEE1 inhibition degrades RRM2 through untimely CDK activation. Therefore, WEE1 inhibition in H3K36me3-deficient cells results in RRM2 reduction, critical dNTP depletion, S-phase arrest, and apoptosis. Accordingly, this synthetic lethality is suppressed by increasing RRM2 expression or inhibiting RRM2 degradation. Finally, we demonstrate that WEE1 inhibitor AZD1775 regresses H3K36me3-deficient tumor xenografts. PMID:26602815

  17. Pullulan encapsulation of labile biomolecules to give stable bioassay tablets.

    PubMed

    Jahanshahi-Anbuhi, Sana; Pennings, Kevin; Leung, Vincent; Liu, Meng; Carrasquilla, Carmen; Kannan, Balamurali; Li, Yingfu; Pelton, Robert; Brennan, John D; Filipe, Carlos D M

    2014-06-10

    A simple and inexpensive method is reported for the long-term stabilization of enzymes and other unstable reagents in premeasured quantities in water-soluble tablets (cast, not compressed) made with pullulan, a nonionic polysaccharide that forms an oxygen impermeable solid upon drying. The pullulan tablets dissolve in aqueous solutions in seconds, thereby facilitating the easy execution of bioassays at remote sites with no need for special reagent handling and liquid pipetting. This approach is modular in nature, thus allowing the creation of individual tablets for enzymes and their substrates. Proof-of-principle demonstrations include a Taq polymerase tablet for DNA amplification through PCR and a pesticide assay kit consisting of separate tablets for acetylcholinesterase and its chromogenic substrate, indoxyl acetate, both of which are highly unstable. The encapsulated reagents remain stable at room temperature for months, thus enabling the room-temperature shipping and storage of bioassay components. PMID:24764260

  18. A New Bioassay for Auxins and Cytokinins 1

    PubMed Central

    Boerjan, Wout; Genetello, Chris; Van Montagu, Marc; Inzé, Dirk

    1992-01-01

    The authors have developed a sensitive bioassay that can be used to detect auxins as well as cytokinins. The bioassay is based on the expression in transformed tobacco (Nicotiana tabacum) mesophyll protoplasts of a chimeric gene, consisting of the upstream sequences of the Agrobacterium tumefaciens gene 5, coupled to the coding sequence of the β-glucuronidase. The expression of this gene is induced by the presence of both auxin and cytokinin in the culture medium. Using this assay, indole-3-acetic acid was detected at 5 × 10−8 molar, whereas trans-zeatin could be detected at 5 × 10−11 molar. The assay can be performed in microtiter plates, allowing numerous samples to be analyzed simultaneously. Only 2.5 × 105 protoplasts are required for one individual assay in 250 microliters of culture medium and for qualitative results, the reaction is readily visualized by ultraviolet light. ImagesFigure 3Figure 4Figure 6 PMID:16668975

  19. Bioassay studies to determine OTEC's effect on phytoplankton activity

    SciTech Connect

    Carmiggelt, C.J.W.; Hartwig, E.O.; Commins, M.L.; Horne, A.J.

    1982-09-01

    The effect of artificially upwelled water (800m) on phytoplankton from 25m and 100m was simulated using five day bioassays. The results show that some enhancement of the phytoplankton populations in the receiving waters due to upwelling is likely to occur. The very small phytoplankton (< 5 um) are most important in this response. The magnitude of the biostimulation cannot be predicted from this study. Ammonia leaks, spills, and venting are probable in an operating OTEC plant. The bioassays show that additions of ammonia will produce biostimulaton only when the P/N ratio indicates nitrogen limitation. In the Hawaiian waters sampled N-limitation was not always present and varied with depth. No nitrogen fixation was detected. The magnitude of stimulation due to ammonia alone was generally less than the addition of upwelled water which is a more complete nutrient mixture.

  20. A Rapid and Simple Bioassay Method for Herbicide Detection

    PubMed Central

    Li, Xiu-Qing; Ng, Alan; King, Russell; Durnford, Dion G.

    2008-01-01

    Chlamydomonas reinhardtii, a unicellular green alga, has been used in bioassay detection of a variety of toxic compounds such as pesticides and toxic metals, but mainly using liquid culture systems. In this study, an algal lawn—agar system for semi-quantitative bioassay of herbicidal activities has been developed. Sixteen different herbicides belonging to 11 different categories were applied to paper disks and placed on green alga lawns in Petri dishes. Presence of herbicide activities was indicated by clearing zones around the paper disks on the lawn 2–3 days after application. The different groups of herbicides induced clearing zones of variable size that depended on the amount, mode of action, and chemical properties of the herbicides applied to the paper disks. This simple, paper-disk-algal system may be used to detect the presence of herbicides in water samples and act as a quick and inexpensive semi-quantitative screening for assessing herbicide contamination. PMID:19578512

  1. Paper bioassay based on ceria nanoparticles as colorimetric probes.

    PubMed

    Ornatska, Maryna; Sharpe, Erica; Andreescu, Daniel; Andreescu, Silvana

    2011-06-01

    We report the first use of redox nanoparticles of cerium oxide as colorimetric probes in bioanalysis. The method is based on changes in the physicochemical properties of ceria nanoparticles, used here as chromogenic indicators, in response to the analyte. We show that these particles can be fully integrated in a paper-based bioassay. To construct the sensor, ceria nanoparticles and glucose oxidase were coimmobilized onto filter paper using a silanization procedure. In the presence of glucose, the enzymatically generated hydrogen peroxide induces a visual color change of the ceria nanoparticles immobilized onto the bioactive sensing paper, from white-yellowish to dark orange, in a concentration-dependent manner. A detection limit of 0.5 mM glucose with a linear range up to 100 mM and a reproducibility of 4.3% for n = 11 ceria paper strips were obtained. The assay is fully reversible and can be reused for at least 10 consecutive measurement cycles, without significant loss of activity. Another unique feature is that it does not require external reagents, as all the sensing components are fixed onto the paper platform. The bioassay can be stored for at least 79 days at room temperature while maintaining the same analytical performance. An example of analytical application was demonstrated for the detection of glucose in human serum. The results demonstrate the potential of this type of nanoparticles as novel components in the development of robust colorimetric bioassays. PMID:21524141

  2. A Bioassay System Using Bioelectric Signals from Small Fish

    NASA Astrophysics Data System (ADS)

    Terawaki, Mitsuru; Soh, Zu; Hirano, Akira; Tsuji, Toshio

    Although the quality of tap water is generally examined using chemical assay, this method cannot be used for examination in real time. Against such a background, the technique of fish bioassay has attracted attention as an approach that enables constant monitoring of aquatic contamination. The respiratory rhythms of fish are considered an efficient indicator for the ongoing assessment of water quality, since they are sensitive to chemicals and can be indirectly measured from bioelectric signals generated by breathing. In order to judge aquatic contamination accurately, it is necessary to measure bioelectric signals from fish swimming freely as well as to stably discriminate measured signals, which vary between individuals. However, no bioassay system meeting the above requirements has yet been established. This paper proposes a bioassay system using bioelectric signals generated from small fish in free-swimming conditions. The system records signals using multiple electrodes to cover the extensive measurement range required in a free-swimming environment, and automatically discriminates changes in water quality from signal frequency components. This discrimination is achieved through an ensemble classification method using probability neural networks to solve the problem of differences between individual fish. The paper also reports on the results of related validation experiments, which showed that the proposed system was able to stably discriminate between water conditions before and after bleach exposure.

  3. Modeling development of inhibition zones in an agar diffusion bioassay.

    PubMed

    Chandrasekar, Vaishnavi; Knabel, Stephen J; Anantheswaran, Ramaswamy C

    2015-09-01

    A two-temperature agar diffusion bioassay is commonly used to quantify the concentration of nisin using Micrococcus luteus as the indicator microorganism. A finite element computational model based on Fick's second law of diffusion was used to predict the radius of the inhibition zone in this diffusion bioassay. The model developed was used to calculate nisin concentration profiles as a function of time and position within the agar. The minimum inhibitory concentration (MIC) of nisin against M. luteus was determined experimentally. The critical time (T c) for growth of M. luteus within the agar diffusion bioassay was experimentally determined using incubation studies with nisin. The radius of the inhibition zone was predicted from the computational model as the location where the predicted nisin concentration at T c was equal to MIC. The MIC was experimentally determined to be 0.156 μg mL(-1), and T c was determined to be 7 h. Good agreement (R (2) = 0.984) was obtained between model-predicted and experimentally determined inhibition zone radii. PMID:26405525

  4. Improved bioassay for detecting autoinducer of Rhodovulum sulfidophilum

    NASA Astrophysics Data System (ADS)

    Terada, T.; Kikuchi, Y.; Umekage, S.

    2015-02-01

    Quorum sensing is a bacterial gene regulation system that enables prompt environmental adaptation in response to cell density. Quorum sensing is driven by an extracellularly secreted chemical signal called autoinducer. Gram-negative bacteria produce one or several types of N-acylhomoserine lactone (AHL) as autoinducers. Our previous study suggests that the gram-negative marine photosynthetic bacterium Rhodovulum sulfidophilum produces AHL in the early stationary phase and plays a role in maintaining the bacterial cell aggregates called "floc". We performed conventional bioassay to identify AHL production by using Chromobacterium violaceum VIR07, which produces violet pigment (violacein) in response to AHL with side chains ranging from C10 to C18 in length. However, we were not able to observe the violacein with good reproducibility, suggesting that inhibitory chemical compounds co-existed in the AHL extract. Therefore, we improved the extraction method; the ethyl acetate-extracted AHLs were fractionated by using reverse phase TLC. By using the re-extracted AHLs for the bioassay, we observed an obvious production of violacein. This result clearly indicates that R. sulfidophilum produces AHLs with side chains ranging from C10 to C18 in length and suggests the utility of improved bioassay for AHL detection.

  5. Modeling development of inhibition zones in an agar diffusion bioassay

    PubMed Central

    Chandrasekar, Vaishnavi; Knabel, Stephen J; Anantheswaran, Ramaswamy C

    2015-01-01

    A two-temperature agar diffusion bioassay is commonly used to quantify the concentration of nisin using Micrococcus luteus as the indicator microorganism. A finite element computational model based on Fick's second law of diffusion was used to predict the radius of the inhibition zone in this diffusion bioassay. The model developed was used to calculate nisin concentration profiles as a function of time and position within the agar. The minimum inhibitory concentration (MIC) of nisin against M. luteus was determined experimentally. The critical time (Tc) for growth of M. luteus within the agar diffusion bioassay was experimentally determined using incubation studies with nisin. The radius of the inhibition zone was predicted from the computational model as the location where the predicted nisin concentration at Tc was equal to MIC. The MIC was experimentally determined to be 0.156 μg mL−1, and Tc was determined to be 7 h. Good agreement (R2 = 0.984) was obtained between model-predicted and experimentally determined inhibition zone radii. PMID:26405525

  6. Novel bioassay using Bacillus megaterium to detect tetracycline in milk.

    PubMed

    Tumini, Melisa; Nagel, Orlando G; Molina, Pilar; Althaus, Rafael L

    2016-01-01

    Tetracyclines are used for the prevention and control of dairy cattle diseases. Residues of these drugs can be excreted into milk. Thus, the aim of this study was to develop a microbiological method using Bacillus megaterium to detect tetracyclines (chlortetracycline, oxytetracycline and tetracycline) in milk. In order to approximate the limits of detection of the bioassay to the Maximum Residue Limit (100μg/l) for milk tetracycline, different concentrations of chloramphenicol (0, 1000, 1500 and 2000μg/l) were tested. The detection limits calculated were similar to the Maximum Residue Limits when a bioassay using B. megaterium ATCC 9885 spores (2.8×10(8)spores/ml) and chloramphenicol (2000μg/l) was utilized. This bioassay detects 105μg/l of chlortetracycline, 100μg/l of oxytetracycline and 134μg/l of tetracycline in 5h. Therefore, this method is suitable to be incorporated into a microbiological multi-residue system for the identification of tetracyclines in milk. PMID:27131738

  7. ESO PR Highlights in 2003

    NASA Astrophysics Data System (ADS)

    2004-01-01

    Among the many astronomical highlights of 2003, the Transit of Mercury certainly attracted great attention as shown by the record number of hits the ESO web page received on that day. But this was a mere rehearsal of an even bigger event we will enjoy in 2004: the Venus Transit. ESO, in partnership with several institutions, is organising a major educational event in connection with it. During 2003, the ESO Educational Office was also involved in various other programmes. They included the web-based "Catch a Star!" and the "Physics and Life" projects, organised with EC sponsorship in connection with the 2003 European Science and Technology Week. The ALMA project, an European-North American collaboration to build an array of 64 12-m submillimetre antennas, moved forward with the signature of the agreement between ESO and the NSF and with the Ground-breaking at Chajnantor. Conceptual studies of a 100-m optical/infrared telescope (OWL) also proceeded well. Several new instruments were installed at ESO telescopes, e.g. HARPS . And the VLT Interferometer (VLTI) received a powerful Adaptive Optics System and made the first detection through infrared interferometry of an extragalactic object. A rapidly increasing number of new scientific results were obtained on the basis of data from ESO telescopes, some of which were highlighted in ESO Press Releases. A number of beautiful images were published. Many of these developments are described in ESO's Press Releases, most with Press Photos, cf. the 2003 PR Index. Some of last year's ESO PR highlights may be accessed directly via the clickable image above.

  8. NTP-CERHR Monograph on the Potential Human Reproductive and Developmental Effects of Di-n-Hexyl Phthalate (DnHP).

    PubMed

    2003-05-01

    The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) conducted an evaluation of the potential for di-n-hexyl phthalate (DnHP) to cause adverse effects on reproduction and development in humans. DnHP is one of 7 phthalate chemicals evaluated by the NTP CERHR Phthalates Expert Panel. These phthalates were selected for evaluation because of high production volume, extent of human exposures, use in children's products, and/or published evidence of reproductive or developmental toxicity. Available information indicates that DnHP is manufactured in relatively small amounts but occurs in a variety of commercial products including dip-molded products such as tool handles or dishwasher baskets, flooring, vinyl gloves, flea collars, and conveyer belts used in food processing. The results of this evaluation on DnHP are published in an NTP-CERHR monograph which includes: 1) the NTP Brief, 2) the Expert Panel Report on the Reproductive and Developmental Toxicity of DnHP, and 3) public comments received on the Expert Panel Report. As stated in the NTP Brief, the NTP reached the following conclusions regarding the possible effects of exposure to DnHP on human development and reproduction. The scientific evidence was insufficient to reach a conclusion regarding the potential for DnHP to adversely affect human development or reproduction. There was very limited information on developmental and reproductive toxicity available to the panel. The panel evaluated only a single developmental toxicity study using a high dose (9,900 mg/kg body weight/day on gestational days 6-13) of DnHP. No live pups were delivered. In a reproductive study, effects on fertility were noted in all treatment groups (380-1,670 mg/ kg body weight/day). These studies provided sufficient information in experimental animals to conclude that DnHP is a reproductive and developmental toxicant at the doses tested. However, the treatment doses were high and these

  9. Recent Highlights of ATVB Atherosclerosis

    PubMed Central

    Lu, Hong; Daugherty, Alan

    2015-01-01

    Summary Mechanistic studies over the past decades using in vitro systems, animal models, and human tissues have highlighted the complexity of pathophysiological processes of atherosclerosis. Hypercholesterolemia, as one of the major risk factors for the development and progression of atherosclerosis, is still the focus of many mechanistic studies and the major therapeutic target of atherosclerosis. Although there is a dire need to validate many experimental findings in humans, there is a large number of approaches that have been showing promise for contributing to future therapeutic strategies. PMID:25717174

  10. Cluster highlights in magnetospheric physics

    NASA Astrophysics Data System (ADS)

    Escoubet, C. Philippe; Laakso, Harri; Taylor, Matthew; Goldstein, Mevlyn; Hapgood, Mike; Masson, Arnaud; Volpp, Juergen; Sieg, Detlef

    The Cluster mission has been operated successfully for 14 years. As the first science mission comprising four identical spacecraft, Cluster has faced many challenges during its lifetime: its long selection process together with SOHO, the failure of the first Ariane V launch, its fast rebuilt, and the launch on two Soyuz rockets in 2000. The separation of the Cluster spacecraft was changed more than 25 times from a few kilometers up to 36000 km to address the various scientific objectives; the smallest distance achieved between two Cluster spacecraft was 4 km, about 50 times smaller than planned at the beginning of the mission. The main goal of the Cluster mission is to study in three dimensions small-scale plasma structures in key plasma regions of Earth’s geospace environment: solar wind and bow shock, magnetopause, polar cusps, magnetotail, plasmasphere and auroral zone. We will present science highlights obtained such as ripples on the bow shock, 3D current measurements and Kelvin-Helmholtz waves at the magnetopause, bifurcated current sheet in the magnetotail, and first measurement of the electron pressure tensor near a site of magnetic reconnection. In addition, we highlight Cluster results on understanding the impact of Coronal Mass Ejections (CME) on the Earth's environment. We will also present the distribution of data through the Cluster Science Data System (CSDS), and the Cluster Archive. Those systems were implemented to provide, for the first time for a plasma physics mission, a permanent and public archive of all the high resolution data from all instruments.

  11. Toxicity of copper-spiked sediments to Tubifex tubifex (Oligochaeta, Tubificidae): Comparison of the 28-day reproductive bioassay with an early-life-stage bioassay

    SciTech Connect

    Vecchi, M.; Pasteris, A.; Bonomi, G. . Dipt. di Biologia Evoluzionistica Sperimentale); Reynoldson, T.B. . National Water Research Inst.)

    1999-06-01

    Two sediment bioassay methods using Tubifex tubifex (Mueller, 1774) as the test species were compared. The first was an adult reproduction test, the second an early-life-stage survival test. The duration of both bioassays is 28 d and the amount of work required was similar; they may be useful alternatives to each other in different circumstances (e.g., the early life stage bioassay could be carried out with smaller volumes of sediment). The two bioassays were performed simultaneously on copper-spiked sediments. Sediments from two freshwater and two terrestrial sites were used; five separate, nonsimultaneous experiments were performed, one for each sediment or soil and a further experiment with soil with a good supplement. In the adult bioassay, there were large differences in the production of cocoons, eggs, and young among the control treatments of the five experiments. There were also major differences in the NOEC and LOEC for copper between the tested substrates. The early life stage bioassay appears to be less sensitive to copper toxicity than the adult reproductive bioassay since NOECs and LOECs are higher for early survival than for the most sensitive endpoints of the adult bioassay in three experiments out of five.

  12. In Vitro Biologic Activities of the Antimicrobials Triclocarban, Its Analogs, and Triclosan in Bioassay Screens: Receptor-Based Bioassay Screens

    PubMed Central

    Ahn, Ki Chang; Zhao, Bin; Chen, Jiangang; Cherednichenko, Gennady; Sanmarti, Enio; Denison, Michael S.; Lasley, Bill; Pessah, Isaac N.; Kültz, Dietmar; Chang, Daniel P.Y.; Gee, Shirley J.; Hammock, Bruce D.

    2008-01-01

    Background Concerns have been raised about the biological and toxicologic effects of the antimicrobials triclocarban (TCC) and triclosan (TCS) in personal care products. Few studies have evaluated their biological activities in mammalian cells to assess their potential for adverse effects. Objectives In this study, we assessed the activity of TCC, its analogs, and TCS in in vitro nuclear-receptor–responsive and calcium signaling bioassays. Materials and methods We determined the biological activities of the compounds in in vitro, cell-based, and nuclear-receptor–responsive bioassays for receptors for aryl hydrocarbon (AhR), estrogen (ER), androgen (AR), and ryanodine (RyR1). Results Some carbanilide compounds, including TCC (1–10 μM), enhanced estradiol (E2)-dependent or testosterone-dependent activation of ER- and AR-responsive gene expression up to 2.5-fold but exhibited little or no agonistic activity alone. Some carbanilides and TCS exhibited weak agonistic and/or antagonistic activity in the AhR-responsive bioassay. TCS exhibited antagonistic activity in both ER- and AR-responsive bioassays. TCS (0.1–10 μM) significantly enhanced the binding of [3H]ryanodine to RyR1 and caused elevation of resting cytosolic [Ca2+] in primary skeletal myotubes, but carbanilides had no effect. Conclusions Carbanilides, including TCC, enhanced hormone-dependent induction of ER- and AR-dependent gene expression but had little agonist activity, suggesting a new mechanism of action of endocrine-disrupting compounds. TCS, structurally similar to noncoplanar ortho-substituted poly-chlorinated biphenyls, exhibited weak AhR activity but interacted with RyR1 and stimulated Ca2+ mobilization. These observations have potential implications for human and animal health. Further investigations are needed into the biological and toxicologic effects of TCC, its analogs, and TCS. PMID:18795164

  13. Microwave-accelerated bioassay technique for rapid and quantitative detection of biological and environmental samples.

    PubMed

    Mohammed, Muzaffer; Syed, Maleeha F; Aslan, Kadir

    2016-01-15

    Quantitative detection of molecules of interest from biological and environmental samples in a rapid manner, particularly with a relevant concentration range, is imperative to the timely assessment of human diseases and environmental issues. In this work, we employed the microwave-accelerated bioassay (MAB) technique, which is based on the combined use of circular bioassay platforms and microwave heating, for rapid and quantitative detection of Glial Fibrillary Acidic Protein (GFAP) and Shiga like toxin (STX 1). The proof-of-principle use of the MAB technique with the circular bioassay platforms for the rapid detection of GFAP in buffer based on colorimetric and fluorescence readouts was demonstrated with a 900W kitchen microwave. We also employed the MAB technique with a new microwave system (called the iCrystal system) for the detection of GFAP from mice with brain injuries and STX 1 from a city water stream. Control bioassays included the commercially available gold standard bioassay kits run at room temperature. Our results show that the lower limit of detection (LLOD) of the colorimetric and fluorescence based bioassays for GFAP was decreased by ~1000 times using the MAB technique and our circular bioassay platforms as compared to the commercially available bioassay kits. The overall bioassay time for GFAP and STX 1 was reduced from 4h using commercially available bioassay kits to 10min using the MAB technique. PMID:26356762

  14. In vivo genotoxicity of furan in F344 rats at cancer bioassay doses

    SciTech Connect

    Ding, Wei

    2012-06-01

    Furan, a potent rodent liver carcinogen, is found in many cooked food items and thus represents a human cancer risk. Mechanisms for furan carcinogenicity were investigated in male F344 rats using the in vivo Comet and micronucleus assays, combined with analysis of histopathological and gene expression changes. In addition, formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III (EndoIII)-sensitive DNA damage was monitored as a measure of oxidative DNA damage. Rats were treated by gavage on four consecutive days with 2, 4, and 8 mg/kg bw furan, doses that were tumorigenic in 2-year cancer bioassays, and with two higher doses, 12 and 16 mg/kg. Rats were killed 3 h after the last dose, a time established as producing maximum levels of DNA damage in livers of furan-treated rats. Liver Comet assays indicated that both DNA strand breaks and oxidized purines and pyrimidines increased in a near-linear dose-responsive fashion, with statistically significant increases detected at cancer bioassay doses. No DNA damage was detected in bone marrow, a non-target tissue for cancer, and peripheral blood micronucleus assays were negative. Histopathological evaluation of liver from furan-exposed animals produced evidence of inflammation, single-cell necrosis, apoptosis, and cell proliferation. In addition, genes related to apoptosis, cell-cycle checkpoints, and DNA-repair were expressed at a slightly lower level in the furan-treated livers. Although a mixed mode of action involving direct DNA binding cannot be ruled out, the data suggest that furan induces cancer in rat livers mainly through a secondary genotoxic mechanism involving oxidative stress, accompanied by inflammation, cell proliferation, and toxicity. -- Highlights: ► Furan is a potent rodent liver carcinogen and represents a human cancer risk. ► Furan induces DNA damage in rat liver at cancer bioassay doses. ► Furan induces oxidative stress, inflammation and cell proliferation in rat liver. ► Expression of

  15. CP VIOLATION HIGHLIGHTS: CIRCA 2005

    SciTech Connect

    SONI A.

    2005-02-27

    Recent highlights in CP violation phenomena, are reviewed. B-factory results imply that, CP-violation phase in the CKM matrix is the dominant contributor to the observed CP violation in K and B-physics. Deviations from the predictions of the CKM-paradigm due to beyond the Standard Model CP-odd phase are likely to be a small perturbation. Therefore, large data sample of clean B's will be needed. Precise determination of the unitarity triangle, along with time dependent CP in penguin dominated hadronic and radiative modes are discussed. Null tests in B, K and top-physics and separate determination of the K-unitarity triangle are also emphasized.

  16. Highlights in pathogenesis of vitiligo.

    PubMed

    Mohammed, Ghada F; Gomaa, Amal Ha; Al-Dhubaibi, Mohammed Saleh

    2015-03-16

    Vitiligo is a common pigmentary disorder. Many studies across decades and all over the world have attempted to illustrate the pathogenesis behind it; however, the pathogenesis of vitiligo remains elusive. This review article, we present the findings behind the most and updated theories behind this psychologically debilitating and disfiguring disease. The discussion begun with the role of genetic predisposition followed by neural theory first proposed in the 1950s. We highlight the autoimmune hypothesis, followed by the reactive oxygen species model, zinc-α2-glycoprotein deficiency hypothesis, viral theory, intrinsic theory and biochemical, molecular and cellular alterations accounting for loss of functioning melanocytes in vitiligo. Many theories were elaborated to clarify vitiligo pathogenesis. It is a multifactorial disease involving the interplay of several factors. Future research is needed to clarify the interaction of these factors for better understanding of vitiligo pathogenesis and subsequent successful treatment. PMID:25789295

  17. Atmospheric Research 2012 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Lau, William K -M.

    2013-01-01

    This annual report, as before, is intended for a broad audience. Our readers include colleagues within NASA, scientists outside the Agency, science graduate students, and members of the general public. Inside are descriptions of atmospheric research science highlights and summaries of our education and outreach accomplishments for calendar year 2012.The report covers research activities from the Mesoscale Atmospheric Processes Laboratory, the Climate and Radiation Laboratory, the Atmospheric Chemistry and Dynamics Laboratory, and the Wallops Field Support Office under the Office of Deputy Director for Atmospheres, Earth Sciences Division in the Sciences and Exploration Directorate of NASAs Goddard Space Flight Center. The overall mission of the office is advancing knowledge and understanding of the Earths atmosphere. Satellite missions, field campaigns, peer-reviewed publications, and successful proposals are essential to our continuing research.

  18. Highlights in pathogenesis of vitiligo

    PubMed Central

    Mohammed, Ghada F; Gomaa, Amal HA; Al-Dhubaibi, Mohammed Saleh

    2015-01-01

    Vitiligo is a common pigmentary disorder. Many studies across decades and all over the world have attempted to illustrate the pathogenesis behind it; however, the pathogenesis of vitiligo remains elusive. This review article, we present the findings behind the most and updated theories behind this psychologically debilitating and disfiguring disease. The discussion begun with the role of genetic predisposition followed by neural theory first proposed in the 1950s. We highlight the autoimmune hypothesis, followed by the reactive oxygen species model, zinc-α2-glycoprotein deficiency hypothesis, viral theory, intrinsic theory and biochemical, molecular and cellular alterations accounting for loss of functioning melanocytes in vitiligo. Many theories were elaborated to clarify vitiligo pathogenesis. It is a multifactorial disease involving the interplay of several factors. Future research is needed to clarify the interaction of these factors for better understanding of vitiligo pathogenesis and subsequent successful treatment. PMID:25789295

  19. Langley aerospace test highlights, 1988

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests which were performed during calendar year 1988 in Langley test facilities, a number of which are unique in the world are highlighted. Both the broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research are illustrated.

  20. Langley aerospace test highlights - 1986

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. This report highlights some of the significant tests which were performed during calendar year 1986 in Langley test facilities, a number of which are unique in the world. The report illustrates both the broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research.

  1. Highlighting inconsistencies regarding metal biosorption.

    PubMed

    Robalds, Artis; Naja, Ghinwa Melodie; Klavins, Maris

    2016-03-01

    Thousands of articles have been devoted to examine different types of biosorbents and their use in cleaning polluted waters. An important objective of some studies has been the identification of the biosorption mechanisms. This type of investigation is not always performed, as it can only be done if scientists are aware of all mechanisms that, at least theoretically, control the removal of the target substances. Mistakes are often made, even in highly cited review articles, where biosorption mechanisms are named and/or grouped. The aim of this article is to highlight errors and inaccuracies as well as to discuss different classification systems of the biosorption mechanisms. This article serves as a guide, as well as a platform for discussion among researchers involved in the investigation of biosorbents, in an effort to avoid reproducing errors in subsequent articles. PMID:26607871

  2. Chlorine disinfection by-products in wastewater effluent: Bioassay-based assessment of toxicological impact.

    PubMed

    Watson, K; Shaw, G; Leusch, F D L; Knight, N L

    2012-11-15

    The potential ecological impact of disinfection by-products (DBPs) present in chlorinated wastewater effluents is not well understood. In this study, the chlorinated effluent of traditional wastewater treatment plants (WWTPs) and advanced water reclamation plants (AWRPs) supplying highly-treated recycled water were analyzed for nitrosamines and trihalomethanes (THMs), and a battery of bioassays conducted to assess effluent toxicity. An increase in general toxicity from DBPs was revealed for all wastewaters studied using an in vitro bioluminescence assay. Examples of androgenic activity and estrogenic activity arising from DBPs at specific sampling sites were also observed. The in vivo model (Artemia franciscana) was generally not adversely affected by exposure to DBPs from any of the chlorinated wastewaters studied. The observed toxicity could not be related to the concentrations of THMs and nitrosamines present, indicating that DBPs not monitored in this study were responsible for this. This work highlights the complexity of DBPs mixtures formed in chlorinated wastewaters, illustrating that toxicity of wastewater DBPs cannot be predicted by chemical monitoring of THMs and nitrosamines. The results suggest bioassays may be particularly useful monitoring tools in assessing toxicity arising from DBPs of these complex waters. The research concludes that DBPs formed in the chlorinated wastewaters studied can be toxic and may have a deleterious impact on aquatic organisms that are exposed to them, and therefore, that chlorination or chlorination/dechlorination may not be adequate treatment strategies for the protection of receiving waters. Chlorinated wastewater toxicity (from DBPs) is not well-understood in the Australian context, and this study serves to advise regulators on this issue. PMID:22981491

  3. Y-Family DNA polymerases may use two different dNTP shapes for insertion: a hypothesis and its implications.

    PubMed

    Chandani, Sushil; Loechler, Edward L

    2009-04-01

    Chemicals and radiation can damage DNA leading to the formation of adducts/lesions, which - if not removed by DNA repair pathways - usually block replicative DNA polymerases (DNAPs). To overcome such potentially lethal blockage, cells have lesion bypass DNAPs, which are often in the Y-Family and include several classes. One class includes human DNAP kappa and E. coli DNAP IV, and they insert dCTP in the non-mutagenic pathway opposite [+ta]-B[a]P-N(2)-dG, which is the major adduct formed by the environmental carcinogen benzo[a]pyrene. Another class includes hDNAP eta and ecDNAP V, and they insert dATP opposite [+ta]-B[a]P-N(2)-dG in the dominant G-->T mutagenic pathway. Herein we develop a hypothesis for why the IV/kappa-class preferentially does cellular dCTP insertion. On the minor groove side of the active site, Y-Family DNAPs have a cleft/hole that can be analyzed based on an analogy to a "chimney." Our models of DNAP IV show a large chimney opening from which the pyrene of [+ta]-B[a]P-N(2)-dG can protrude, which allows canonical adduct-dG:dCTP pairing. In contrast, our models of DNAP V have small chimney openings that forces adduct-dG downward in the active site such that canonical adduct-dG:dCTP pairing is not possible. Based on X-ray structures, sequence alignment and our modeled structures of Y-Family DNAPs, chimney opening size seems primarily controlled by one amino acid ("flue-handle"), which dictates whether nearby amino acids ("flue") plug the chimney or not. Based on this analysis, a correlation is apparent: the flue is closed in V/eta-class DNAPs giving small chimney openings, while the flue is open for the IV/kappa-class giving large chimney openings. Secondarily, a hypothesis is developed for why the V/eta-class might preferentially do cellular dATP insertion opposite [+ta]-B[a]P-N(2)-dG: the small chimney forces adduct-dG lower in the active site, possibly leading to catalysis using a non-canonical dNTP shape that permits syn-adenine:adduct-dG base

  4. Highlights of Coastal Waves 1996.

    NASA Astrophysics Data System (ADS)

    Rogers, David P.; Dorman, Clive E.; Edwards, Kathleen A.; Brooks, Ian M.; Melville, W. Kendall; Burk, Stephen D.; Thompson, William T.; Holt, Teddy; Ström, Linda M.; Tjernström, Michael; Grisogono, Branko; Bane, John M.; Nuss, Wendell A.; Morley, Bruce M.; Schanot, Allen J.

    1998-07-01

    Some of the highlights of an experiment designed to study coastal atmospheric phenomena along the California coast (Coastal Waves 1996 experiment) are described. This study was designed to address several problems, including the cross-shore variability and turbulent structure of the marine boundary layer, the influence of the coast on the development of the marine layer and clouds, the ageostrophy of the flow, the dynamics of trapped events, the parameterization of surface fluxes, and the supercriticality of the marine layer.Based in Monterey, California, the National Center for Atmospheric Research (NCAR) C-130 Hercules and the University of North Carolina Piper Seneca obtained a comprehensive set of measurements on the structure of the marine layer. The study focused on the effects of prominent topographic features on the wind. Downstream of capes and points, narrow bands of high winds are frequently encountered. The NCAR-designed Scanning Aerosol Backscatter Lidar (SABL) provided a unique opportunity to connect changes in the depth of the boundary layer with specific features in the dynamics of the flow field.An integral part of the experiment was the use of numerical models as forecast and diagnostic tools. The Naval Research Laboratory's Coupled Ocean Atmosphere Model System (COAMPS) provided high-resolution forecasts of the wind field in the vicinity of capes and points, which aided the deployment of the aircraft. Subsequently, this model and the MIUU (University of Uppsala) numerical model were used to support the analysis of the field data.These are some of the most comprehensive measurements of the topographically forced marine layer that have been collected. SABL proved to be an exceptionally useful tool to resolve the small-scale structure of the boundary layer and, combined with in situ turbulence measurements, provides new insight into the structure of the marine atmosphere. Measurements were made sufficiently far offshore to distinguish between the

  5. ESO PR Highlights in 2000

    NASA Astrophysics Data System (ADS)

    2001-01-01

    At the beginning of the new millennium, ESO and its staff are facing the future with confidence. The four 8.2-m Unit Telescopes of the Very Large Telescope (VLT) are in great shape and the VLT Interferometer (VLTI) will soon have "first fringes". The intercontinental ALMA project is progressing well and concepts for extremely large optical/infrared telescopes are being studied. They can also look back at a fruitful and rewarding past year. Perhaps the most important, single development has been the rapid transition of the Very Large Telescope (VLT). From being a "high-tech project under construction" it has now become a highly proficient, world-class astronomical observatory. This trend is clearly reflected in ESO's Press Releases , as more and more front-line scientific results emerge from rich data obtained at this very efficient facility. There were also exciting news from several of the instruments at La Silla. At the same time, the ESO community may soon grow, as steps towards membership are being taken by various European countries. Throughout 2000, a total of 54 PR communications were made, with a large number of Press Photos and Video Clips, cf. the 2000 PR Index. Some of the ESO PR highlights may be accessed directly via the clickable image on the present page. ESO PR Photo 01/01 is also available in a larger (non-clickable) version [ JPEG: 566 x 566 pix - 112k]. It may be reproduced, if credit is given to the European Southern Observatory.

  6. Data Mining in the U.S. National Toxicology Program (NTP) Database Reveals a Potential Bias Regarding Liver Tumors in Rodents Irrespective of the Test Agent

    PubMed Central

    Ring, Matthias; Eskofier, Bjoern M.

    2015-01-01

    Long-term studies in rodents are the benchmark method to assess carcinogenicity of single substances, mixtures, and multi-compounds. In such a study, mice and rats are exposed to a test agent at different dose levels for a period of two years and the incidence of neoplastic lesions is observed. However, this two-year study is also expensive, time-consuming, and burdensome to the experimental animals. Consequently, various alternatives have been proposed in the literature to assess carcinogenicity on basis of short-term studies. In this paper, we investigated if effects on the rodents’ liver weight in short-term studies can be exploited to predict the incidence of liver tumors in long-term studies. A set of 138 paired short- and long-term studies was compiled from the database of the U.S. National Toxicology Program (NTP), more precisely, from (long-term) two-year carcinogenicity studies and their preceding (short-term) dose finding studies. In this set, data mining methods revealed patterns that can predict the incidence of liver tumors with accuracies of over 80%. However, the results simultaneously indicated a potential bias regarding liver tumors in two-year NTP studies. The incidence of liver tumors does not only depend on the test agent but also on other confounding factors in the study design, e.g., species, sex, type of substance. We recommend considering this bias if the hazard or risk of a test agent is assessed on basis of a NTP carcinogenicity study. PMID:25658102

  7. New technique for collecting ambient diesel particles for bioassays

    SciTech Connect

    Hallock, M.F.; Smith, T.J.; Hammond, S.K.; Beck, B.D.; Brain, J.D.

    1987-05-01

    This paper describes a new application of viable aerosol sampler, the Liquid electrostatic Aerosol Precipitator (LEAP), for the collection of diesel particles for bioassays of pulmonary toxicity and mutagenicity or carinogenicity. Currently used methods (filtration, dry electrostatic precipitation) cause agglomeration of particles and increases in particle size up to twenty-fold, which may alter particle toxicity significantly. Collection of diesel particles with the LEAP preserved submicronic particle size. Differences in chemical composition of extracts of surface adsorbents as compared to particles collected on filters also were observed. This technique may be applicable for collection other types of combustion products or oil mists that agglomerate when collected by filtration.

  8. A new technique for collecting ambient diesel particles for bioassays.

    PubMed

    Hallock, M F; Smith, T J; Hammond, S K; Beck, B D; Brain, J D

    1987-05-01

    This paper describes a new application of a viable aerosol sampler, the Liquid Electrostatic Aerosol Precipitator (LEAP), for the collection of diesel particles for bioassays of pulmonary toxicity and mutagenicity or carcinogenicity. Currently used methods (filtration, dry electrostatic precipitation) cause agglomeration of particles and increases in particle size up to twenty-fold, which may alter particle toxicity significantly. Collection of diesel particles with the LEAP preserved submicronic particle size. Differences in chemical composition of extracts of surface adsorbents as compared to particles collected on filters also were observed. This technique may be applicable for collection of other types of combustion products or oil mists that agglomerate when collected by filtration. PMID:2438921

  9. Field and Bioassay Indicators for Internal Dose Intervention Therapy

    SciTech Connect

    Carbaugh, Eugene H.

    2007-05-01

    Guidance is presented that is used at the U.S. Department of Energy Hanford Site to identify the potential need for medical intervention in response to intakes of radioactivity. The guidance, based on ICRP Publication 30 models and committed effective dose equivalents of 20 mSv and 200 mSv, is expressed as numerical workplace measurements and derived first-day bioassay results for large intakes. It is used by facility radiation protection staff and on-call dosimetry support staff during the first few days following an intake.

  10. Field and bioassay indicators for internal dose intervention therapy.

    PubMed

    Carbaugh, Eugene H

    2007-05-01

    Guidance is presented that is used at the U.S. Department of Energy Hanford Site to identify the potential need for medical intervention in response to intakes of radioactivity. The guidance, based on ICRP Publication 30 models and committed effective dose equivalents of 20 mSv and 200 mSv, is expressed as numerical workplace measurements and derived first-day bioassay results for large intakes. It is used by facility radiation protection staff and on-call dosimetry support staff during the first few days following an intake. PMID:17440323

  11. Electroantennographic bioassay as a screening tool for host plant volatiles.

    PubMed

    Beck, John J; Light, Douglas M; Gee, Wai S

    2012-01-01

    Plant volatiles play an important role in plant-insect interactions. Herbivorous insects use plant volatiles, known as kairomones, to locate their host plant. When a host plant is an important agronomic commodity feeding damage by insect pests can inflict serious economic losses to growers. Accordingly, kairomones can be used as attractants to lure or confuse these insects and, thus, offer an environmentally friendly alternative to pesticides for insect control. Unfortunately, plants can emit a vast number volatiles with varying compositions and ratios of emissions dependent upon the phenology of the commodity or the time of day. This makes identification of biologically active components or blends of volatile components an arduous process. To help identify the bioactive components of host plant volatile emissions we employ the laboratory-based screening bioassay electroantennography (EAG). EAG is an effective tool to evaluate and record electrophysiologically the olfactory responses of an insect via their antennal receptors. The EAG screening process can help reduce the number of volatiles tested to identify promising bioactive components. However, EAG bioassays only provide information about activation of receptors. It does not provide information about the type of insect behavior the compound elicits; which could be as an attractant, repellent or other type of behavioral response. Volatiles eliciting a significant response by EAG, relative to an appropriate positive control, are typically taken on to further testing of behavioral responses of the insect pest. The experimental design presented will detail the methodology employed to screen almond-based host plant volatiles by measurement of the electrophysiological antennal responses of an adult insect pest navel orangeworm (Amyelois transitella) to single components and simple blends of components via EAG bioassay. The method utilizes two excised antennae placed across a "fork" electrode holder. The protocol

  12. An emergency bioassay method for (210)Po in urine.

    PubMed

    Guérin, Nicolas; Dai, Xiongxin

    2015-09-01

    A rapid method was developed to efficiently measure (210)Po in urine samples in an emergency situation. Polonium-210 in small urine samples (10 mL) was spontaneously deposited on a stainless steel disc in 1 M HCl at room temperature for 4 h in a polyethylene bottle. The metallic disc was then counted for 4 h by alpha spectrometry. The developed method allowed the preparation of large sample batch in a short time. The method meets the requirements for an emergency bioassay procedure. PMID:26115206

  13. How to Fabricate Functional Artificial Luciferases for Bioassays.

    PubMed

    Kim, Sung-Bae; Fujii, Rika

    2016-01-01

    The present protocol introduces fabrication of artificial luciferases (ALuc(®)) by extracting the consensus amino acids from the alignment of copepod luciferase sequences. The made ALucs have unique sequential identities that are phylogenetically distinctive from those of any existing copepod luciferase. Some ALucs exhibited heat stability, and strong and greatly prolonged optical intensities. The made ALucs are applicable to various bioassays as an optical readout, including live cell imaging, single-chain probes, and bioluminescent tags of antibodies. The present protocol guides on how to fabricate a unique artificial luciferase with designed optical properties and functionalities. PMID:27424894

  14. ESO PR Highlights in 2004

    NASA Astrophysics Data System (ADS)

    2005-01-01

    new interesting scientific results on the basis of data from ESO telescopes, including several results from the unmatched interferometer mode of the VLT, the VLTI, some of which were highlighted in ESO Press Releases. Certainly worth noting is the possible first ever bona-fide image of an exoplanet and the discovery of the lightest known exoplanet . At the beginning of the year, Paranal welcomed the first Auxiliary Telescope, while on the instrument side as well, 2004 was a good year: we saw the arrival of SINFONI on the VLT, of AMBER on the VLTI, and the installation at the NACO Adaptive Optics instrument of the " Simultaneous Differential Imager (SDI)" to detect exoplanets. And the first prototype of the Astrophysical Virtual Observatory was able to provide unprecedented results on the existence of Type-2 quasars by discovering an entire population of obscured, powerful supermassive black holes. Many of these developments are described in ESO's Press Releases, most with Press Photos, cf. the 2004 PR Index. Some of last year's ESO PR highlights may be accessed directly via the clickable image above.

  15. Highlighting Your Science to NASA

    NASA Astrophysics Data System (ADS)

    Sharkey, C.

    2003-12-01

    An effort is underway to provide greater visibility within NASA headquarters, and to those who provide funding to NASA, of the outstanding work that is being performed by scientists involved in the Solar System Exploration Research and Analysis Programs, most of whom are DPS members. In support of this effort, a new feature has been developed for the NASA Headquarters Solar System Exploration Division web site whereby researchers can provide a synopsis of their current research results. The site (http://solarsystem.nasa.gov/spotlight/ - Username: your email address Password: sse) is an online submission area where NASA-funded scientists can upload the results of their research. There they provide their contact information, briefly describe their research, and upload any associated images or graphics. The information is available to a limited number of reviewers and writers at JPL. Each month, one researcher's work will be chosen as a science spotlight. After a writer interviews the scientist, a brief Power Point presentation that encapsulates their work will be given to Dr. Colleen Hartman at NASA headquarters. She will then present the exciting findings to Associate Administrator for Space Science, Dr. Ed Weiler. The information from some of these highlights can serve as a basis to bring Principal Investigators to NASA Headquarters for exposure to media through Space Science Updates on NASA television. In addition, the science results may also be incorporated into briefing material for the Office of Management and Budget and congressional staffers. Some spotlights will also be converted into feature stories for the Solar System Exploration website so the public, too, can learn about exciting new research. The site, http://solarsystem.nasa.gov/, is one of NASA's most visited. Over the past decade, there has been a trend of flat budgets for Research and Analysis activities. By giving more visibility to results of Solar System research, our goal is to encourage

  16. ESO PR Highlights in 2005

    NASA Astrophysics Data System (ADS)

    2006-01-01

    2005 was the year of Physics. It was thus also in part the year of astronomy and this is clearly illustrated by the numerous breakthroughs that were achieved, in particular using ESO's telescopes. One of the highlights was without any doubt the confirmation of the first image of an exoplanet , around the star 2M1207 (see ESO PR 12/05). ESO's telescopes also found a Neptune-mass exoplanet around a small star ( PR 30/05) - a discovery that proves crucial in the census of other planetary systems, and imaged a tiny companion in the close vicinity of the star GQ Lupi, a very young object still surrounded by a disc, with an age between 100,000 and 2 million years ( PR 09/05). Moreover, using a new high-contrast adaptive optics camera on the VLT, the NACO Simultaneous Differential Imager, or NACO SDI, astronomers were able for the first time to image a companion 120 times fainter than its star , very near the star AB Doradus A. This companion appears to be almost twice as heavy as theory predicts it to be ( PR 02/05). ESO's telescopes proved very useful in helping to solve a 30-year old puzzle . Astronomers have for the first time observed the visible light from a short gamma-ray burst (GRB). Using the 1.5m Danish telescope at La Silla (Chile), they showed that these short, intense bursts of gamma-ray emission most likely originate from the violent collision of two merging neutron stars ( PR 26/05). Additional evidence came from witnessing another event with the VLT ( PR 32/05). Also in this field, astronomers found the farthest known gamma-ray burst with ESO's VLT, observing an object with a redshift 6.3, i.e. that is seen when the Universe was less than 900 million years old ( PR 22/05). On July 4, NASA's Deep Impact spacecraft plunged onto Comet 9P/Tempel 1 with the aim to create a crater and expose pristine material from beneath the surface. For two days before and six days after, all major ESO telescopes have been observing the comet, in a coordinated fashion and in

  17. ESO PR Highlights in 2001

    NASA Astrophysics Data System (ADS)

    2002-01-01

    great research possibilities at these sites. And this year will also see further development of Europe's Astrophysical Virtual Observatory, a most powerful research tool of the future. Many of these developments are described in ESO's Press Releases , most with Press Photos and several also with PR Video Clips , cf. the 2001 PR Index. Some of last year's ESO PR highlights may be accessed directly via the clickable image on the present page.

  18. Highlights of Astronomy, Volume 14

    NASA Astrophysics Data System (ADS)

    van der Hucht, Karel

    2007-08-01

    Preface Karel A. van der Hucht; Part I. Invited Discourses: Part II. Joint Discussions: 1. Particle acceleration - from Solar System to AGN Marian Karlicky and John C. Brown; 2. Pulsar emission and related phenomena Werner Becker, Janusz A. Gil and Bronislaw Rudak; 3. Solar activity regions and magnetic structure Debi Prasad Choudhary and Michal Sobotka; 4. The ultraviolet universe: Stars from birth to death Ana I. Gomez de Castro and Martin A. Barstow; 5. Calibrating the top of the stellar M-L relationship Claus Leitherer, Anthony F. J. Moat and Joachim Puls; 6. Neutron stars and black holes in star clusters Frederic A. Rasio; 7. The Universe at z > 6 Daniel Schaerer and Andrea Ferrara; 8. Solar and stellar activity cycles Klaus G. Strassmeier and Alexander Kosovichev; 9. Supernovae: One millennium after SN 1006 P. Frank Winkler, Wolfgang Hillebrandt and Brian P. Schmidt; 10. Progress in planetary exploration missions Guy J. Consolmagno; 11. Pre-solar grains as astrophysical tools Anja C. Andersen and John C. Lattanzio; 12. Long wavelength astrophysics T. Joseph W. Lazio and Namir E. Kassim; 13. Exploiting large surveys for galactic astronomy Christopher J. Corbally, Coryn A. L. Bailer-Jones, Sunetra Giridhar and Thomas H. Lloyd Evans; 14. Modeling dense stellar systems Alison I. Sills, Ladislav Subr and Simon F. Portegies Zwart; 15. New cosmology results from the Spitzer Space Telescope George Helou and David T. Frayer; 16. Nomenclature, precession and new models in fundamental astronomy Nicole Capitaine, Jan Vondrak & James L. Hilton; 17. Highlights of recent progress in seismology of the Sun and Sun-like stars John W. Leibacher and Michael J. Thompson; Part III. Special Sessions: SpS 1. Large astronomical facilities of the next decade Gerard F. Gilmore and Richard T. Schilizzi; SpS 2. Innovation in teaching and learning astronomy methods Rosa M. Ros and Jay M. Pasachoff; SpS 3. The Virtual Observatory in action: New science, new technology and next

  19. Results of screening NCI/NTP nongenotoxic carcinogens and genotoxic noncarcinogens with the k sub e test

    SciTech Connect

    Mendelsohn, M.L.; Bakale, G.; McCreary, R.D.

    1989-01-01

    The interdependence of the electrophilic and carcinogenic properties of chemicals that was demonstrated two decades ago rekindled interest in the somatic mutation theory of carcinogenesis. Interest in this theory grew with the development of a reverse-mutation bacterial assay in the laboratory of B.N. Ames that permitted the mutagenic properties of the chemicals to be determined quickly and yielded results which indicated that carcinogens are mutagens.'' Subsequent validation studies of this bioassay, the Salmonella typhimurium/microsome or Ames test,'' by Ames' group and others provided additional support for the correlation between mutagenicity and carcinogenicity which led to the worldwide deployment of the Ames test in thousands of laboratories and to the development of more than 100 other short-term tests that continue to be used to identify potential carcinogens via various end-points of genotoxicity. This document discusses electrophilicity, mutagenicity, and carcinogenicity relationships as well as carcinogen-screening of chemicals. 28 refs., 4 tabs.

  20. [Evaluation of Antilles fish ciguatoxicity by mouse and chick bioassays].

    PubMed

    Pottier, I; Vernoux, J P

    2003-03-01

    Ciguatera is a common seafood poisoning in Western Atlantic and French West Indies. Ciguatera fish poisoning in the Caribbean is a public health problem. A toxicological study was carried out on 178 Caribbean fish specimens (26 species) captured off Guadeloupe and Saint Barthelemy between 1993 and 1999. The mouse bioassay and the chick feeding test were used to control fish edibility. Ciguatoxins presence was assumed when symptomatology was typical of ciguatera in mouse and chick. Fishes were classified in three groups: non toxic fish (edible), low toxic fish (not edible) and toxic fish (not edible). 75% of fishes were non toxic. Toxic fish specimens belonged to four families of high trophic level carnivores: Carangidae, Lutjanidae, Serranidae et Sphyraenidae. Percentages of toxic fishes to humans reached 55% for Caranx latus and 33% for Caranx bartholomaei and Caranx lugubris. Only a significant correlation between weight and toxicity was only found for C. latus and snappers. Small carnivorous groupers (Serranidae) were also toxic. Atoxic fish species were (a) pelagic fish (Coryphaena hippurus, Auxis thazard and Euthynnus pelamis), (b) invertebrates feeders (Malacanthus plumieri, Balistes vetula), (c) small high-risk fish or (d) fish of edible benthic fish families. Liver of four fishes (Mycteroperca venenosa, Caranx bartholomaei, Seriola rivoliana, Gymnothorax funebris) contained ciguatoxins at a significant level although their flesh was safe. This study confirms the usefulness of mouse and chick bioassays for sanitary control of fish. PMID:12784589

  1. A Bioassay for Lafora Disease and Laforin Glucan Phosphatase Activity

    PubMed Central

    Sherwood, Amanda R.; Johnson, Mary Beth; Delgado-Escueta, Antonio V.; Gentry, Matthew S.

    2013-01-01

    Objectives Lafora disease is a rare yet invariably fatal form of progressive neurodegenerative epilepsy resulting from mutations in the phosphatase laforin. Several therapeutic options for Lafora disease patients are currently being explored, and these therapies would benefit from a biochemical means of assessing functional laforin activity following treatment. To date, only clinical outcomes such as decreases in seizure frequency and severity have been used to indicate success of epilepsy treatment. However, these qualitative measures exhibit variability and must be assessed over long periods of time. In this work, we detail a simple and sensitive bioassay that can be used for the detection of functional endogenous laforin from human and mouse tissue. Design and methods We generated antibodies capable of detecting and immunoprecipitating endogenous laforin. Following laforin immunoprecipitation, laforin activity was assessed via phosphatase assays using para-nitrophenylphosphate (pNPP) and a malachite green-based assay specific for glucan phosphatase activity. Results We found that antibody binding to laforin does not impede laforin activity. Furthermore, the malachite green-based glucan phosphatase assay used in conjunction with a rabbit polyclonal laforin antibody was capable of detecting endogenous laforin activity from human and mouse tissue. Importantly, this assay discriminated between laforin activity and other phosphatases. Conclusions The bioassay that we have developed utilizing laforin antibodies and an assay specific for glucan phosphatase activity could prove valuable in the rapid detection of functional laforin in patients to which novel Lafora disease therapies have been administered. PMID:24012855

  2. Dichloromethane attracts diabroticite larvae in a laboratory behavioral bioassay.

    PubMed

    Jewett, D K; Bjostad, L B

    1996-07-01

    A two-choice laboratory behavioral bioassay was used to demonstrate that dichloromethane elicits the dose-dependent attraction of secondinstar western and southern corn rootworms. Preliminary data suggest that second-instar banded cucumber beetles are also attracted to dichloromethane. An eluotropic series of 10 materials, including distilled water, ethanol, methanol, acetone, ethyl dichloroacetate, dichloromethane, diethyl ether, benzene, hexadecane, and hexane, was tested for attraction of western corn rootworm larvae. Dichloromethane was the only one attractive at all doses tested, and orthogonal comparisons revealed a quadratic trend (convex) for responses of larvae to increasing dose. Benzene and hexadecane also attracted larvae, but significantly fewer than dichloromethane, and only at three doses and one dose, respectively. Orthogonal comparisons revealed no linear or quadratic trend for responses of larvae to increasing doses of either compound. Dichloromethane is the first organic compound demonstrated to attract western corn rootworm larvae in the absence of carbon dioxide. Carbon dioxide has previously been reported to attract western corn rootworm larvae either independently or when combined with other organic compounds, and the sensitivity of our bioassay was tested by demonstrating the dose-dependent attraction of western corn rootworm larvae to carbonated water as a carbon dioxide source. We have also demonstrated the attraction of southern corn rootworm larvae to carbon dioxide and propose that carbon dioxide and dichloromethane behave analogously when they interact with chemoreceptor sites on larvae. PMID:24226089

  3. Vicia faba bioassay for environmental toxicity monitoring: A review.

    PubMed

    Iqbal, Munawar

    2016-02-01

    Higher plants are recognized as excellent genetic models to detect cytogenetic and mutagenic agents and are frequently used in environmental monitoring studies. Vicia faba (V. faba) bioassay have been used to study DNA damages i.e., chromosomal and nuclear aberrations induced by metallic compounds, pesticides, complex mixtures, petroleum derivates, toxins, nanoparticles and industrial effluents. The main advantages of using V. faba is its availability round the year, economical to use, easy to grow and handle; its use does not require sterile conditions, rate of cell division is fast, chromosomes are easy to score, less expensive and more sensitive as compared to other short-term tests that require pre-preparations. The V. faba test offers evaluation of different endpoints and tested agents can be classified as cytotoxic/genotoxic/mutagenic. This test also provides understanding about mechanism of action, whether the tested agent is clastogenic or aneugenic in nature. In view of advantages offered by V. faba test system, it is used extensively to assess toxic agents and has been emerged as an important bioassay for ecotoxicological studies. Based on the applications of V. faba test to assess the environmental quality, this article offers an overview of this test system and its efficiency in assessing the cytogenetic and mutagenic agents in different classes of the environmental concerns. PMID:26414739

  4. Atmospheric Research 2014 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Platnick, Steven

    2015-01-01

    Earth Sciences Division in atmospheric science research. Figure 1.1 shows the 20-year record of peer-reviewed publications and proposals among the various Laboratories. This data shows that the scientific work being conducted in the Laboratories is competitive with the work being done elsewhere in universities and other government agencies. The office of Deputy Director for Atmospheric Research will strive to maintain this record by rigorously monitoring and promoting quality while emphasizing coordination and integration among atmospheric disciplines. Also, an appropriate balance will be maintained between the scientists' responsibility for large collaborative projects and missions and their need to carry out active science research as a principal investigator. This balance allows members of the Laboratories to improve their scientific credentials, and develop leadership potentials. Interdisciplinary research is carried out in collaboration with other laboratories and research groups within the Earth Sciences Division, across the Sciences and Exploration Directorate, and with partners in universities and other government agencies. Members of the Laboratories interact with the general public to support a wide range of interests in the atmospheric sciences. Among other activities, the Laboratories raise the public's awareness of atmospheric science by presenting public lectures and demonstrations, by making scientific data available to wide audiences, by teaching, and by mentoring students and teachers. The Atmosphere Laboratories make substantial efforts to attract and recruit new scientists to the various areas of atmospheric research. We strongly encourage the establishment of partnerships with Federal and state agencies that have operational responsibilities to promote the societal application of our science products. This report describes our role in NASA's mission, provides highlights of our research scope and activities, and summarizes our scientists' major

  5. ESO PR Highlights in 2006

    NASA Astrophysics Data System (ADS)

    2007-01-01

    Last year proved to be another exceptional year for the European organisation for ground-based astronomy. ESO should begin the New Year with two new member states: Spain (PR 05/06) and the Czech Republic (PR 52/06). ESO PR Highlights 2006 2006 was a year of renovation and revolution in the world of planets. A new Earth-like exoplanet has been discovered (PR 03/06) using a network of telescopes from all over the world (including the Danish 1.54-m one at ESO La Silla). It is not the only child of this fruitful year: thanks to the combined use of ESO's Very Large Telescope (VLT) and La Silla instruments, a surprising system of twin giant exoplanets was found (PR 29/06), and a trio of Neptune-like planets hosted by a nearby star were identified (PR 18/06). These results open new perspectives on the search for habitable zones and on the understanding of the mechanism of planet formation. The VISIR instrument on the VLT has been providing unique information to answer this last question, by supplying a high resolution view of a planet-forming disc (PR 36/06). There are not only new members in the planets' register: during the General Assembly of the International Astronomical Union held in Prague (Czech Republic), it was decided that Pluto is not a planet anymore but a 'dwarf planet'. Whatever its status, Pluto still has a satellite, Charon, whose radius and density have been measured more accurately by observing a rare occultation from different sites, including Cerro Paranal (PR 02/06). The scientific community dedicated 2006 to the great physicist James Clerk Maxwell (it was the 175th anniversary of the birth): without his electromagnetic theory of light, none of the astonishing discoveries of modern physics could have been achieved. Nowadays we can look at distant galaxies in great detail: the GIRAFFE spectrograph on the VLT revealed that galaxies 6 billion years ago had the same amount of dark matter relative to stars than nowadays (PR 10/06), while SINFONI gave an

  6. ESO PR Highlights in 2007

    NASA Astrophysics Data System (ADS)

    2008-01-01

    Another great year went by for ESO, the European Organisation for Astronomical Research in the Southern Hemisphere. From 1 January 2007, with the official joining of the Czech Republic, ESO has 13 member states, and since September, ESO has a new Director General, Tim de Zeeuw (ESO 03/07 and 38/07). Many scientific discoveries were made possible with ESO's telescopes. Arguably, the most important is the discovery of the first Earth-like planet in the habitable zone of a low-mass red dwarf (ESO 22/07). If there is water on this planet, then it should be liquid! ESO PR Highlights 2007 This is a clickable map. These are only some of the press releases issued by ESO in 2007. For a full listing, please go to ESO 2007 page. In our own Solar System also, astronomers made stunning breakthroughs with ESO's telescopes, observing the effect of the light from the Sun on an asteroid's rotation (ESO 11/07), describing in unprecedented detail the double asteroid Antiope (ESO 18/07), peering at the rings of Uranus (ESO 37/07), discovering a warm south pole on Neptune (ESO 41/07), showing a widespread and persistent morning drizzle of methane over the western foothills of Titan's major continent (ESO 47/07), and studying in the greatest details the wonderful Comet McNaught (ESO 05/07 and 07/07). In the study of objects slightly more massive than planets, the VLT found that brown dwarfs form in a similar manner to normal stars (ESO 24/07). The VLT made it also possible to measure the age of a fossil star that was clearly born at the dawn of time (ESO 23/07). Other discoveries included reconstructing the site of a flare on a solar-like star (ESO 53/07), catching a star smoking (ESO 34/07), revealing a reservoir of dust around an elderly star (ESO 43/07), uncovering a flat, nearly edge-on disc of silicates in the heart of the magnificent Ant Nebula (ESO 42/07), finding material around a star before it exploded (ESO 31/07), fingerprinting the Milky Way (ESO 15/07), revealing a rich

  7. Defective mitochondrial respiration, altered dNTP pools and reduced AP endonuclease 1 activity in peripheral blood mononuclear cells of Alzheimer's disease patients

    PubMed Central

    Maynard, Scott; Hejl, Anne-Mette; Dinh, Thuan-Son T.; Keijzers, Guido; Hansen, Åse M.; Desler, Claus; Moreno-Villanueva, Maria; Bürkle, Alexander; Rasmussen, Lene J.; Waldemar, Gunhild; Bohr, Vilhelm A.

    2015-01-01

    AIMS Accurate biomarkers for early diagnosis of Alzheimer's disease (AD) are badly needed. Recent reports suggest that dysfunctional mitochondria and DNA damage are associated with AD development. In this report, we measured various cellular parameters, related to mitochondrial bioenergetics and DNA damage, in peripheral blood mononuclear cells (PBMCs) of AD and control participants, for biomarker discovery. METHODS PBMCs were isolated from 53 patients with AD of mild to moderate degree and 30 age-matched healthy controls. Tests were performed on the PBMCs from as many of these participants as possible. We measured glycolysis and mitochondrial respiration fluxes using the Seahorse Bioscience flux analyzer, mitochondrial ROS production using flow cytometry, dNTP levels by way of a DNA polymerization assay, DNA strand breaks using the Fluorometric detection of Alkaline DNA Unwinding (FADU) assay, and APE1 incision activity (in cell lysates) on a DNA substrate containing an AP site (to estimate DNA repair efficiency). RESULTS In the PBMCs of AD patients, we found reduced basal mitochondrial oxygen consumption, reduced proton leak, higher dATP level, and lower AP endonuclease 1 activity, depending on adjustments for gender and/or age. CONCLUSIONS: This study reveals impaired mitochondrial respiration, altered dNTP pools and reduced DNA repair activity in PBMCs of AD patients, thus suggesting that these biochemical activities may be useful as biomarkers for AD. PMID:26539816

  8. Relationships between human vitality and mitochondrial respiratory parameters, reactive oxygen species production and dNTP levels in peripheral blood mononuclear cells

    PubMed Central

    Gram, Martin; Desler, Claus; Bendix, Laila; Budtz-Jørgensen, Esben; Molbo, Drude; Croteau, Deborah L.; Osler, Merete; Stevnsner, Tinna; Rasmussen, Lene Juel; Dela, Flemming; Avlund, Kirsten; Bohr, Vilhelm A.

    2013-01-01

    Low vitality (a component of fatigue) in middle-aged and older adults is an important complaint often identified as a symptom of a disease state or side effect of a treatment. No studies to date have investigated the potential link between dysfunctional mitochondrial ATP production and low vitality. Therefore, we measured a number of cellular parameters related to mitochondrial activity in peripheral blood mononuclear cells (PBMCs) isolated from middle-aged men, and tested for association with vitality. These parameters estimate mitochondrial respiration, reactive oxygen species (ROS) production, and deoxyribonucleotide (dNTP) balance in PBMCs. The population was drawn from the Metropolit cohort of men born in 1953. Vitality level was estimated from the Medical Outcomes Study Short Form 36 (SF-36) vitality scale. We found that vitality score had no association with any of the mitochondrial respiration parameters. However, vitality score was inversely associated with cellular ROS production and cellular deoxythymidine triphosphate (dTTP) levels and positively associated with deoxycytidine triphosphate (dCTP) levels. We conclude that self-reported persistent low vitality is not associated with specific aspects of mitochondrial oxidative phosphorylation capacity in PBMCs, but may have other underlying cellular dysfunctions that contribute to dNTP imbalance and altered ROS production. PMID:24304678

  9. Resistance monitoring of Heliothis virescens to pyramided cotton varieties with a hydrateable, artificial cotton leaf bioassay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proof of concept was demonstrated for a practical, off the shelf bioassay to monitor for tobacco budworm resistance to pyramided Bt cotton using plant eluants. The bioassay was based on a previously described feeding disruption test using hydrateable artificial diet containing a blue indicator dye, ...

  10. Comparison of two mosquito bioassay methods for the estimate of minimum effective dose in repellents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is expected that laboratory-based repellent bioassays should reliably evaluate the efficacy of compounds that deter mosquito feeding behavior. The variety of repellent bioassays available allows for flexibility in design, but makes it difficult to compare any two methods, including in vitro and i...

  11. Profiling Animal Toxicants by Automatically Mining Public Bioassay Data: A Big Data Approach for Computational Toxicology

    PubMed Central

    Zhang, Jun; Hsieh, Jui-Hua; Zhu, Hao

    2014-01-01

    In vitro bioassays have been developed and are currently being evaluated as potential alternatives to traditional animal toxicity models. Already, the progress of high throughput screening techniques has resulted in an enormous amount of publicly available bioassay data having been generated for a large collection of compounds. When a compound is tested using a collection of various bioassays, all the testing results can be considered as providing a unique bio-profile for this compound, which records the responses induced when the compound interacts with different cellular systems or biological targets. Profiling compounds of environmental or pharmaceutical interest using useful toxicity bioassay data is a promising method to study complex animal toxicity. In this study, we developed an automatic virtual profiling tool to evaluate potential animal toxicants. First, we automatically acquired all PubChem bioassay data for a set of 4,841 compounds with publicly available rat acute toxicity results. Next, we developed a scoring system to evaluate the relevance between these extracted bioassays and animal acute toxicity. Finally, the top ranked bioassays were selected to profile the compounds of interest. The resulting response profiles proved to be useful to prioritize untested compounds for their animal toxicity potentials and form a potential in vitro toxicity testing panel. The protocol developed in this study could be combined with structure-activity approaches and used to explore additional publicly available bioassay datasets for modeling a broader range of animal toxicities. PMID:24950175

  12. Effects of Wind Speed on Aerosol Spray Penetration in Adult Mosquito Bioassay Cages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioassay cages are commonly used to assess efficacy of insecticides against adult mosquitoes in the field. To properly correlate adult mortality readings to insecticidal efficacy and/or spray application parameters, it is important to know how the cage used in the bioassay interacts with the spray ...

  13. LIFE CYCLE BIOASSAY FOR ASSESSMENT OF THE EFFECTS OF TOXIC CHEMICALS USING RAPID CYCLING OF BRASSICA

    EPA Science Inventory

    Initial evaluation of a new plant life cycle bioassay for the assessment of the effects of toxic chemicals is presented. he bioassay features a rapid cycling Brassica species that can complete its life cycle in as little as 36 days. he herbicide dalapon (2,2 dichloropropionic aci...

  14. Immunochemical technologies for replacement of rodent bioassays in sensitive detection of toxins in foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rapid sensitive assays for biothreat toxins that can be used to detect intentionally contaminated foods are now typically performed via bioassay in live mice. While bioassay provides essential data on bioavailability, animal models are technically, fiscally, and ethically challenging. Through carefu...

  15. Improved high-throughput bioassay for Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As we gain more information through functional genomic studies of Rhyzopertha dominica (F.), we need a high throughput bioassay system to screen potential biopesticides. R. dominica is an internal feeder during immature stages and presents unique challenges with traditional bioassay methods. Our pri...

  16. Development of a High Throughput Translational Bioassay for Plant Biofuel Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using the well developed microbial system, Clostridium phytofermentans, we have developed a robust bioassay for biomass digestibility and conversion to biofuels. The bioassay can be used to measure the impact of plant genetic diversity on digestibility, and thereby determine the potential effects of...

  17. A Bioassay for Determining Resistance Levels in Tarnished Plant Bug Populations to Neonicotinoid Insecticides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory bioassay was developed and used to test field populations of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), for resistance development to the neonicitinoid insecticides imidacloprid (Trimax®) and thiamethoxam (Centric®). The bioassay determined LC50 values by feeding...

  18. A LABORATORY BIOASSAY FOR MONITORING RESISTANCE IN TARNISHED PLANT BUG POPULATIONS TO NEONICOTINOID INSECTICIDES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A laboratory bioassay was developed for testing tarnished plant bug populations for resistance development to the neonicotinoid insecticides imidacloprid and thiamethoxam. The bioassay allows for the determination of LC50 values by feeding known doses of the insecticides to adult tarnished plant bu...

  19. Prediction of rodent carcinogenicity of further 30 chemicals bioassayed by the US National Toxicology Program

    SciTech Connect

    Benigni, R.; Andreoli, C.; Zito, R.

    1996-10-01

    Recently the US National Toxicology Program (NTP) sponsored a comparative exercise in which different prediction approaches (both biologically and chemically based) were challenged for their predictive abilities of rodent carcinogenicity of a common set of chemicals. The exercise enjoyed remarkable scientific success and stimulated NTP to sponsor a second challenging round of tests, inviting participants to present predictions relative to the rodent carcinogenicity of a further 30 chemicals; these are currently being tested. In this article, we present our predictions based on structure-activity relationship considerations. In our procedure, first each chemical was assigned to an activity mechanism class and then, with semiquantitative considerations, was assigned a probability carcinogenicity score, taking into account simultaneously the hypothesized action mechanism and physical chemical parameters. 31 refs., 2 tabs.

  20. Characterization of the environmental quality of sediments from two estuarine systems based on different in-vitro bioassays.

    PubMed

    Fernandes, Denise; Pujol, Silvia; Pérez-Albaladejo, Elisabet; Tauler, Romà; Bebianno, Maria João; Porte, Cinta

    2014-05-01

    This study characterizes the environmental quality of sediments from the Arade and Guadiana estuaries using different in-vitro bioassays: a) fish hepatoma cell line (PLHC-1) to determine cytotoxicity and presence of CYP1A and oxidative stress inducing agents; b) gonad subcellular fractions from sea bass (Dicentrarchus labrax) to detect compounds that are likely to act as endocrine disrupters by interfering with the synthesis of androgens (CYP17, CYP11β) and estrogens (CYP19). Approximately 60% of extracts from the Arade estuary were cytotoxic when tested at 60 mg eQsed/mL, while only one sample from Guadiana showed cytotoxicity. Sediments from Arade collected close to harbours and waste water effluents were enriched with CYP1A inducing agents, while those from the upper Guadiana induced oxidative stress in PLHC-1 cells. On the other hand, several extracts from both estuaries were able to significantly inhibit CYP17, CYP11β and CYP19 activities in gonad subcellular fractions of sea bass, which indicates the presence of endocrine disrupters, particularly in several sites from the Arade estuary. Overall, the study highlights the usefulness of in-vitro bioassays to identify those sediments that could pose risk to aquatic organisms and that require further action to improve their environmental quality. PMID:24140013

  1. Benthic invertebrate bioassays with toxic sediment and pore water

    USGS Publications Warehouse

    Giesy, John P.; Rosiu, Cornell J.; Graney, Robert L.; Henry, Mary G.

    1990-01-01

    The relative sensitivities of bioassays to determine the toxicity of sediments were investigated and three methods of making the sample dilutions required to generate dose-response relationships were compared. The assays studied were: (a) Microtox®, a 15-min assay ofPhotobacterium phosphoreum bioluminescence inhibition by pore water; (b) 48-h Daphnia magnalethality test in pore water; (c) 10-d subchronic assay of lethality to and reduction of weight gain by Chironomus tentans performed in either whole sediment or pore water; (d) 168-h acute lethality assay of Hexagenia limbata in either whole sediment or pore water. The three methods of diluting sediments were: (a) extracting pore water from the toxic location and dilution with pore water from the control station; (b) diluting whole sediment from the toxic location with control whole sediment from a reference location, then extracting pore water; and (c) diluting toxic, whole sediment with whole sediment from a reference location, then using the whole sediment in bioassays. Based on lethality, H. limbata was the most sensitive organism to the toxicity of Detroit River sediment. Lethality of D. magna in pore water was similar to that of H. limbata in whole sediment and can be used to predict effects of whole sediment toxicity to H. limbata. The concentration required to cause a 50% reduction in C. tentans growth (10-d EC50) was approximately that which caused 50% lethality of D. magna (48-h LC50) and was similar to the toxicity that restricts benthic invertebrate colonization of contaminated sediments. While the three dilution techniques gave similar results with some assays, they gave very different results in other assays. The dose-response relationships determined by the three dilution techniques would be expected to vary with sediment, toxicant and bioassay type, and the dose-response relationship derived from each technique needs to be interpreted accordingly.

  2. Evaluation of the mutagenicity and carcinogenicity of motor vehicle emissions in short-term bioassays.

    PubMed Central

    Lewtas, J

    1983-01-01

    Incomplete combustion of fuel in motor vehicles results in the emission of submicron carbonaceous particles which, after cooling and dilution, contain varying quantities of extractable organic constituents. These organics are mutagenic in bacteria. Confirmatory bioassays in mammalian cells provide the capability of detecting chromosomal and DNA damage in addition to gene mutations. In order to evaluate the mutagenicity of these organics in mammalian cells, extractable organics from particle emissions from several diesel and gasoline vehicles were compared in a battery of microbial, mammalian cell and in vivo bioassays. The mammalian cell mutagenicity bioassays were selected to detect gene mutations, DNA damage, and chromosomal effects. Carcinogenesis bioassays conducted included short-term assays for oncogenic transformation and skin tumorigenesis. The results in different assay systems are compared both qualitatively and quantitatively. Good quantitative correlations were observed between several mutagenesis and carcinogenesis bioassays for this series of diesel and gasoline emissions. PMID:6186475

  3. Chronic and Initiation/Promotion Skin Bioassays of Petroleum Refinery Streams.

    PubMed Central

    Skisak, C; Furedi-Machacek, EM; Schmitt, SS; Swanson, MS; Vernot, EH

    1994-01-01

    Nine refinery streams were tested in both chronic and initiation/promotion (I/P) skin bioassays. In the chronic bioassay, groups of 50 C3H/HeJ mice received twice weekly applications of 50 microl of test article for at least 2 years. In the initiation phase of the I/P bioassay, groups of CD-1 mice received an initiating dose of 50 microl of test article for 5 consecutive days, followed by promotion with 50 microl of phorbol-12-myristate-13-acetate (0.01% w/v in acetone) for 25 weeks. In the promotion phase of the I/P bioassay, CD-1 mice were initiated with 50 microl of 7,12-dimethylbenzanthracene (0.1% w/v in acetone) or acetone, followed by promotion with 50 microl of test article twice weekly for 25 weeks. The most volatile of the streams, sweetened naphtha, and the least volatile, vacuum residuum, were noncarcinogenic in both assays. Middle distillates, with a boiling range of 150 degrees-370 degreesC, demonstrated carcinogenic activity in the chronic bioassay and acted as promoters but not initiators in the I/P bioassay. Untreated mineral oil streams displayed initiating activity and were carcinogenic in the chronic bioassay, presumably due to the presence of polycyclic aromatic hydrocarbons of requisite size and structure. A highly solvent-refined mineral oil stream lacked initiating activity. These results indicate that the I/P bioassay, which takes 6 months to complete, may be a good qualitative predictor of the results of a chronic bioassay, at least for petroleum streams. Furthermore, the I/P bioassay can provide insight into possible mechanisms of tumor development. Images p82-a PMID:9719673

  4. Harvester ant bioassay for assessing hazardous chemical waste sites

    SciTech Connect

    Gano, K.A.; Carlile, D.W.; Rogers, L.E.

    1984-12-01

    A technique was developed for using harvester ants, Pogonomyrmex owhyeei, in terrestrial bioassays. Procedures were developed for maintaining stock populations, handling ants, and exposing ants to toxic materials. Relative toxicities were determined by exposing ants to 10 different materials. These materials included three insecticides, Endrin, Aldrin, and Dieldrin; one herbicide, 2,4-D; three oil-like compounds, wood preservative, drilling fluid, and slop oil; and three heavy metals, copper, zinc, and cadmium. Ants were exposed in petri dishes containing soil amended with a particular toxicant. Under these test conditions, ants showed no sensitivity to the metals or 2,4-D. Ants were sensitive to the insecticides and oils in repeated tests, and relative toxicity remained consistent throughout. Aldrin was the most toxic material, followed by Dieldrin, Endrin, wood preservative, drilling fluid, and slop oil. 10 refs., 2 figs., 2 tabs.

  5. Acute bioassays with benthic macroinvertebrates conducted in situ

    SciTech Connect

    Whaley, M.; Garcia, R.; Sy, J. )

    1989-10-01

    Several methods of toxicity testing using macroinvertebrates in controlled laboratory experiments have been reported. Researchers conducted bioassays with natural assemblages of benthic macroinvertebrates exposed to several petroleum refinery effluents. They found that the populations of invertebrates declined after only a few days of exposure. The objective of the study was to determine the acute toxic effects of discharge water from a petrochemical complex on a natural assemblage of benthic macroinvertebrates. The discharge water consisted of refinery wastewater and sanitary wastewater, as well as brine discharge from a power/desalination plant. The benthic macroinvertebrates were transplanted from a healthy reef area to the outfall channel receiving the discharge water. The study began on October 7, 1985, and concluded that same week. Any decrease in specific species would indicate that the discharge was toxic to these species. These species could also serve as indicators of toxic conditions at other locations.

  6. A sediment suspension system for bioassays with small aquatic organisms

    USGS Publications Warehouse

    Schmidt-Dallmier, M. J.; Atchison, G.J.; Steingraeber, M.T.; Knights, B.C.

    1992-01-01

    Exposure of aquatic organisms to suspended sediments can impair growth and survival and increase bioaccumulation of sediment-associated contaminants. However, evaluation of the effects of suspended sediments and their associated contaminants on aquatic organisms has been hampered by the lack of a practical and inexpensive exposure system for conducting bioassays. We present a cost-effective system for assessing the effects of suspended sediments and associated contaminants on small aquatic organisms. A 7-day suspension test was conducted with nominal sediment concentrations ranging from 0.0 To 5.0 g 1-1. The system maintained relatively constant suspended sediment concentrations, as measured by turbidity, and caused minimal mortality to test organisms.

  7. Use of bioassay methods to evaluate incinerator emissions

    SciTech Connect

    Watts, R.R.; DeMarini, D.M.; Linak, W.P.; Lemieux, P.M.; McSorley, J.A.

    1989-01-01

    The organic components in combustion emissions are composed of thousands of chemicals. Analyzing such a complex mixture for the presence of even a few selected chemicals is difficult and provides information on only a fraction of the chemicals present. Reliance on such limited chemical analysis for determining possible health effects may ignore the contribution of many other chemical components of the effluent. Because combustion emissions are complex mixtures, they have been evaluated as such, rather than by studying a few selected chemicals that might be present. The Salmonella (Ames) assay was used to determine the mutagenicity associated with particles from the effluent of municipal-waste combustors, from ambient air collected near a municipal-waste combustor, and from the effluent of a pilot-sized rotary kiln in which polyethylene was combusted. Filter samples were extracted with dichloromethane, and concentrated extracts were solvent exchanged into dimethyl sulfoxide for bioassay.

  8. Toxicity assessment using different bioassays and microbial biosensors.

    PubMed

    Hassan, Sedky H A; Van Ginkel, Steven W; Hussein, Mohamed A M; Abskharon, Romany; Oh, Sang-Eun

    2016-01-01

    Toxicity assessment of water streams, wastewater, and contaminated sediments, is a very important part of environmental pollution monitoring. Evaluation of biological effects using a rapid, sensitive and cost effective method can indicate specific information on ecotoxicity assessment. Recently, different biological assays for toxicity assessment based on higher and lower organisms such as fish, invertebrates, plants and algal cells, and microbial bioassays have been used. This review focuses on microbial biosensors as an analytical device for environmental, food, and biomedical applications. Different techniques which are commonly used in microbial biosensing include amperometry, potentiometry, conductometry, voltammetry, microbial fuel cells, fluorescence, bioluminescence, and colorimetry. Examples of the use of different microbial biosensors in assessing a variety of environments are summarized. PMID:27071051

  9. A novel bioassay using root re-growth in Lemna.

    PubMed

    Park, Areum; Kim, Youn-Jung; Choi, Eun-Mi; Brown, Murray T; Han, Taejun

    2013-09-15

    A new phytotoxicity test method based on root elongation of three Lemna species (Lemna gibba, L. minor, and L. paucicostata) has been developed. Tests with aquatic plants have, typically, favored measurements on fronds (e.g. frond number, area, biomass) rather than on roots, due, in part, to issues associated with handling fragile roots and the time-consuming procedures of selecting roots with identical root lengths. The present method differs in that roots were excised prior to exposure with subsequent measurements on newly developed roots. Results show that there were species-specific difference in sensitivity to the five metals tested (Ag, Cd, Cr, Cu and Hg), with Ag being the most toxic (EC50=5.3-37.6 μgL(-1)) to all three species, and Cr the least toxic for L. gibba and L. minor (1148.3 and 341.8 μgL(-1), respectively) and Cu for L. paucicostata (470.4 μgL(-1)). Direct comparisons were made with measurements of frond area, which were found to be less sensitive. More generally, root re-growth was shown to reflect the toxic responses of all three Lemna species to these five important metals. The root growth bioassay differs from three internationally standardized methods (ISO, OCED and US EPA) in that it is completed in 48 h, the required volume of test solutions is only 3 ml and non-axenic plants are used. Our results show that the Lemna root method is a simple, rapid, cost-effective, sensitive and precise bioassay to assess the toxic risks of metals and has practical application for monitoring municipal and industrial waste waters where metals are common constituents. PMID:23917640

  10. Comprehensive integration of homogeneous bioassays via centrifugo-pneumatic cascading.

    PubMed

    Godino, Neus; Gorkin, Robert; Linares, Ana V; Burger, Robert; Ducrée, Jens

    2013-02-21

    This work for the first time presents the full integration and automation concept for a range of bioassays leveraged by cascading a centrifugo-pneumatic valving scheme to sequentially move several liquids through shared channel segments for multi-step sample preparation into the detection zone. This novel centrifugo-pneumatic liquid handling significantly simplifies system manufacture by obviating the need for complex surface functionalization procedures or hybrid material integration, as it is common in conventional valving methods such as capillary burst valves or sacrificial valves. Based on the centrifugo-pneumatic valving scheme, this work presents a toolkit of operational elements implementing liquid loading/transfer, metering, mixing and sedimentation in a microstructured polymer disc. As a proof of concept for the broad class of homogeneous bioassays, the full integration and automation of a colorimetric nitrate/nitrite test for the detection of clinically relevant nitric oxide (NO) in whole blood is implemented. First, 40 μL of plasma is extracted from a 100 μL sample of human blood, incubated for one hour with the enzymatic mixture (60 μL), and finally reacted with 100 μL of colorimetric (Greiss) reagents. Following just a single loading phase at the beginning of the process, all of these steps are automated through the centrifugo-pneumatic cascade with a high level of flow control and synchronization. Our system shows good correlation with controls up to 50 μM of nitrate, which adequately covers the healthy human range (4 to 45.3 μM). PMID:23250328

  11. Evolving BioAssay Ontology (BAO): modularization, integration and applications

    PubMed Central

    2014-01-01

    The lack of established standards to describe and annotate biological assays and screening outcomes in the domain of drug and chemical probe discovery is a severe limitation to utilize public and proprietary drug screening data to their maximum potential. We have created the BioAssay Ontology (BAO) project (http://bioassayontology.org) to develop common reference metadata terms and definitions required for describing relevant information of low-and high-throughput drug and probe screening assays and results. The main objectives of BAO are to enable effective integration, aggregation, retrieval, and analyses of drug screening data. Since we first released BAO on the BioPortal in 2010 we have considerably expanded and enhanced BAO and we have applied the ontology in several internal and external collaborative projects, for example the BioAssay Research Database (BARD). We describe the evolution of BAO with a design that enables modeling complex assays including profile and panel assays such as those in the Library of Integrated Network-based Cellular Signatures (LINCS). One of the critical questions in evolving BAO is the following: how can we provide a way to efficiently reuse and share among various research projects specific parts of our ontologies without violating the integrity of the ontology and without creating redundancies. This paper provides a comprehensive answer to this question with a description of a methodology for ontology modularization using a layered architecture. Our modularization approach defines several distinct BAO components and separates internal from external modules and domain-level from structural components. This approach facilitates the generation/extraction of derived ontologies (or perspectives) that can suit particular use cases or software applications. We describe the evolution of BAO related to its formal structures, engineering approaches, and content to enable modeling of complex assays and integration with other ontologies and

  12. Evolving BioAssay Ontology (BAO): modularization, integration and applications.

    PubMed

    Abeyruwan, Saminda; Vempati, Uma D; Küçük-McGinty, Hande; Visser, Ubbo; Koleti, Amar; Mir, Ahsan; Sakurai, Kunie; Chung, Caty; Bittker, Joshua A; Clemons, Paul A; Brudz, Steve; Siripala, Anosha; Morales, Arturo J; Romacker, Martin; Twomey, David; Bureeva, Svetlana; Lemmon, Vance; Schürer, Stephan C

    2014-01-01

    The lack of established standards to describe and annotate biological assays and screening outcomes in the domain of drug and chemical probe discovery is a severe limitation to utilize public and proprietary drug screening data to their maximum potential. We have created the BioAssay Ontology (BAO) project (http://bioassayontology.org) to develop common reference metadata terms and definitions required for describing relevant information of low-and high-throughput drug and probe screening assays and results. The main objectives of BAO are to enable effective integration, aggregation, retrieval, and analyses of drug screening data. Since we first released BAO on the BioPortal in 2010 we have considerably expanded and enhanced BAO and we have applied the ontology in several internal and external collaborative projects, for example the BioAssay Research Database (BARD). We describe the evolution of BAO with a design that enables modeling complex assays including profile and panel assays such as those in the Library of Integrated Network-based Cellular Signatures (LINCS). One of the critical questions in evolving BAO is the following: how can we provide a way to efficiently reuse and share among various research projects specific parts of our ontologies without violating the integrity of the ontology and without creating redundancies. This paper provides a comprehensive answer to this question with a description of a methodology for ontology modularization using a layered architecture. Our modularization approach defines several distinct BAO components and separates internal from external modules and domain-level from structural components. This approach facilitates the generation/extraction of derived ontologies (or perspectives) that can suit particular use cases or software applications. We describe the evolution of BAO related to its formal structures, engineering approaches, and content to enable modeling of complex assays and integration with other ontologies and

  13. Using lone star ticks, Amblyomma americanum (Acari: Ixodidae) in in vitro laboratory bioassays of repellents: dimensions, duration, and variability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The in vitro bioassay is an important tool in repellent discovery and development, with a variety of bioassays used in recent years. Several factors, such as the dimensions and configuration of test surfaces and duration of tick exposure, can influence the outcome of bioassays. We tested two tick re...

  14. An in vitro rainbow trout cell bioassay for AhR-mediated toxins

    SciTech Connect

    Richter, C.A.; Giesy, J.P.; Denison, M.S.

    1995-12-31

    The toxicity of PCBs, dioxins, and other halogenated aromatic hydrocarbons (HAHS) at environmentally relevant concentrations is in large part mediated through the aromatic hydrocarbon receptor (AhR). Bioassays which measure the activity of genes regulated by the receptor provide an integrative measure of the total AhR-mediated toxicity of a sample. The authors have recently developed and characterized a bioassay using recombinant rainbow trout hepatoma cells containing the firefly luciferase reporter gene under the regulation of the AhR. The cell line is designated Remodulated Lightning Trout (RLT). The RLT bioassay is relevant to fish, and is useful as a rapid screening device, a guide for chemical analysis, and a tool for studies of the AhR mechanism. The responses of the RLT cell line to various PCB congeners are similar to responses of in vivo fish bioassays. The authors now report on the responses of the bioassay to dioxins, dibenzofurans, and other related compounds as compared to in vivo fish bioassays. The authors will also report on the utility of the RLT bioassay in measuring the total TEQ of complex mixtures.

  15. Evaluation and simplification of the assimilable organic carbon nutrient bioassay for bacterial growth in drinking water.

    PubMed

    Kaplan, L A; Bott, T L; Reasoner, D J

    1993-05-01

    A modified assimilable organic carbon (AOC) bioassay is proposed. We evaluated all aspects of the AOC bioassay technique, including inoculum, incubation water, bioassay vessel, and enumeration technique. Other concerns included eliminating the need to prepare organic carbon-free glassware and minimizing the risks of bacterial and organic carbon contamination. Borosilicate vials (40 ml) with Teflon-lined silicone septa are acceptable incubation vessels. Precleaned vials are commercially available, and the inoculum can be injected directly through the septa. Both bioassay organisms, Pseudomonas fluorescens P-17 and Spirillum sp. strain NOX, are available from the American Type Culture Collection and grow well on R2A agar, making this a convenient plating medium. Turbid raw waters need to be filtered prior to an AOC analysis. Glass fiber filters used with either a peristaltic pump or a syringe-type filter holder are recommended for this purpose. A sampling design that emphasizes replication of the highest experimental level, individual batch cultures, is the most efficacious way to reduce the total variance associated with the AOC bioassay. Quality control for the AOC bioassay includes an AOC blank and checks for organic carbon limitation and inhibition of the bioassay organisms. PMID:8517748

  16. Using an Electronic Highlighter to Eliminate the Negative Effects of Pre-Existing, Inappropriate Highlighting

    ERIC Educational Resources Information Center

    Gier, Vicki; Kreiner, David; Hudnell, Jason; Montoya, Jodi; Herring, Daniel

    2011-01-01

    The purpose of the present experiment was to determine whether using an active learning technique, electronic highlighting, can eliminate the negative effects of pre-existing, poor highlighting on reading comprehension. Participants read passages containing no highlighting, appropriate highlighting, or inappropriate highlighting. We hypothesized…

  17. Sensitive, Rapid, and Specific Bioassay for the Determination of Antilipogenic Compounds

    PubMed Central

    Ulitzur, S.; Goldberg, I.

    1977-01-01

    A sensitive and rapid bioassay for the determination of the antilipogenic compounds cerulenin and CM-55 is described. The bioassay is based on the inhibitory effect of cerulenin and CM-55 on the in vivo luminescence of an aldehyde-requiring mutant of the marine bacterium Beneckea harveyi. A total quantity as low as 0.1 μg of cerulenin can be determined within 15 min with an error of ±2%. The bioassay, as presented, is specific for compounds that are known to inhibit fatty acid biosynthesis and, as such, it might be used as a general screening method for the detection of antilipogenic compounds. PMID:303076

  18. Analyzing bioassay data using Bayesian methods -- A primer

    SciTech Connect

    Miller, G.; Inkret, W.C.; Schillaci, M.E.

    1997-10-16

    The classical statistics approach used in health physics for the interpretation of measurements is deficient in that it does not allow for the consideration of needle in a haystack effects, where events that are rare in a population are being detected. In fact, this is often the case in health physics measurements, and the false positive fraction is often very large using the prescriptions of classical statistics. Bayesian statistics provides an objective methodology to ensure acceptably small false positive fractions. The authors present the basic methodology and a heuristic discussion. Examples are given using numerically generated and real bioassay data (Tritium). Various analytical models are used to fit the prior probability distribution, in order to test the sensitivity to choice of model. Parametric studies show that the normalized Bayesian decision level k{sub {alpha}}-L{sub c}/{sigma}{sub 0}, where {sigma}{sub 0} is the measurement uncertainty for zero true amount, is usually in the range from 3 to 5 depending on the true positive rate. Four times {sigma}{sub 0} rather than approximately two times {sigma}{sub 0}, as in classical statistics, would often seem a better choice for the decision level.

  19. Target organs in chronic bioassays of 533 chemical carcinogens

    SciTech Connect

    Gold, L.S.; Slone, T.H.; Manley, N.B. ); Bernstein, L. )

    1991-06-01

    A compendium of carcinogenesis bioassay results organized by target organ is presented for 533 chemicals that are carcinogenic in at least one species. This compendium is based primarily on experiments in rats or mice; results in hamsters, nonhuman primates, and dogs are also reported. The compendium can be used to identify chemicals that induce tumors at particular sites, and to determine whether target sites are the same for chemicals positive in more than one species. The Carcinogenic Potency Database (CPDB), which includes results of 3969 experiments, is used in the analysis. The published CPDB includes details on each test, and literature references. Chemical carcinogens are reported for 35 different target organs in rats or mice. More than 80% of the carcinogens in each of these species are positive in at least one of the 8 most frequent target sites; liver, lung, mammary gland, stomach, vascular system, kidney, hematopoietic system, and urinary bladder. An analysis is presented of how well one can predict the carcinogenic response in mice from results in rats, or vice versa. Among chemicals tested in both species, 76% of rat carcinogens are positive in mice, and 71% of mouse carcinogens are positive in rats. Prediction is less accurate to the same target site: 52% of rat carcinogens are positive in the same site in mice, and 48% of mouse carcinogens are positive in the same site in rats. The liver is the most frequent site in common between rats and mice.

  20. Using enzyme bioassays as a rapid screen for metal toxicity

    USGS Publications Warehouse

    Choate, LaDonna M.; Ross, P.E.; Blumenstein, E. P.; Ranville, James F.

    2005-01-01

    Mine tailings piles and abandoned mine soils are often contaminated by a suite of toxic metals, which were released in the mining process. Traditionally, toxicity of such areas has been determined by numerous chemical methods including the Toxicity Characteristic Leachate Procedure (TCLP) and traditional toxicity tests using organisms such as the cladoceran Ceriodaphnia dubia. Such tests can be expensive and time-consuming. Enzymatic bioassays may provide an easier, less costly, and more time-effective toxicity screening procedure for mine tailings and abandoned mine soil leachates. This study evaluated the commercially available MetPLATE™ enzymatic toxicity assay test kit. The MetPLATE™ assay uses a modified strain of Escherichia coli bacteria as the test organism. Toxicity is defined by the activity of β-galactosidase enzyme which is monitored colorometrically with a 96-well spectrophotometer. The study used water samples collected from North Fork Clear Creek, a mining influenced water (MIW) located in Colorado. A great benefit to using the MetPLATE™ assay over the TCLP is that it shows actual toxicity of a sample by taking into account the bioavailability of the toxicants rather than simply measuring the metal concentration present. Benefits of the MetPLATE™ assay over the use of C. dubia include greatly reduced time for the testing process (∼2 hours), a more continuous variable due to a greater number of organisms present in each sample (100,000+), and the elimination of need to maintain a culture of organisms at all times.

  1. Bioassays on Illinois waterway dredged material. Final report

    SciTech Connect

    Moore, D.W.; Gibson, A.B.; Dillon, T.M.

    1992-12-01

    Sediment from the Illinois Waterway navigation channel is hydraulically dredged by the US Army Engineer District, Rock Island, and placed in the nearshore environment via pipeline. Water returning to the river can have a high-suspended solids load approaching fluid mud consistency. There is a concern that this return water may exceed the State of Illinois water quality standards for ammonia and have adverse effects on aquatic life. To address these concerns, composite sediment samples and site water collected from selected sites in the Illinois Waterway were evaluated in toxicity tests. Acute (48-hr) toxicity tests were conducted with two species, Pimephales promelas (the fathead minnow) and Daphnia magna (a freshwater cladoceran). A chronic (21-day) toxicity test was also conducted using Daphnia magna. Animals were exposed separately to different concentrations of filtered and unfiltered elutriates prepared from Acute, Cadmium, Daphnia magna, Pimephales promela, Ammonia, Chronic, Elutriate, Sediment, Bioassay, Cladoceran, Fathead minnow. Illinois Waterway edged material. Total ammonia concentrations were measured in all tests and the un-ionized fraction was calculated by adjusting for temperature and pH. Tests were conducted at the US Army Engineer Waterways Experiment Station, Vicksburg, MS. In addition, as part of an interlaboratory effort, a 48-hr acute toxicity test with Pimephales pomelas fry was conducted concurrently by the Hygienic Laboratory of the University of Iowa, Des Moines, IA.

  2. Long-wavelength-emitting nanocrystals for bioassay applications

    NASA Astrophysics Data System (ADS)

    Leppert, Valerie J.; Harvey, Ashley S.; McCool, Geoff D.; Quinlan, Forest T.; Feng, Jun; Shan, Guomin; Stroeve, Pieter; Risbud, Subhash H.; Hammock, Bruce D.; Kennedy, Ian M.

    2002-11-01

    New fluorophores that can be excited using visible or near-infrared radiation are of considerable interest for application in environmental and complex bioassays, where background fluorescence is exacerbated by ultra-violet or blue excitation. Useful labels for biomolecules include infrared emitting semiconductor nanoparticles that can be blue-shifted into the near-infrared and visible through quantum confinement effects, oxides of iron, and rare earth oxides. In this work, the synthesis of 6 nm average diameter lead selenide nanocrystals (well below the Bohr exciton diameter of 92 nm) through a reverse micelle technique; and the synthesis of iron and europium oxides with particles less than 5 nm in diameter by pulsed laser ablation is reported. The europium oxide nanoparticles' emission showed a large Stokes shift (144 nm or 216 nm, depending on excitation wavelength); a narrow, symmetric emission line at 610 nm (FWHM of 8 nm); and long lifetime (300 μs). The Eu2O3 nanoparticles, which were coated with silica for functionalization, displayed a greatly enhanced sensitivity over a conventional ELISA (0.025 ng ml-1 vs. 0.1 ng ml-1) when run in an atrazine immunoassay.

  3. Detection of Organic Compounds with Whole-Cell Bioluminescent Bioassays

    PubMed Central

    Xu, Tingting; Close, Dan; Smartt, Abby; Ripp, Steven

    2015-01-01

    Natural and manmade organic chemicals are widely deposited across a diverse range of ecosystems including air, surface water, groundwater, wastewater, soil, sediment, and marine environments. Some organic compounds, despite their industrial values, are toxic to living organisms and pose significant health risks to humans and wildlife. Detection and monitoring of these organic pollutants in environmental matrices therefore is of great interest and need for remediation and health risk assessment. Although these detections have traditionally been performed using analytical chemical approaches that offer highly sensitive and specific identification of target compounds, these methods require specialized equipment and trained operators, and fail to describe potential bioavailable effects on living organisms. Alternatively, the integration of bioluminescent systems into whole-cell bioreporters presents a new capacity for organic compound detection. These bioreporters are constructed by incorporating reporter genes into catabolic or signaling pathways that are present within living cells and emit a bioluminescent signal that can be detected upon exposure to target chemicals. Although relatively less specific compared to analytical methods, bioluminescent bioassays are more cost-effective, more rapid, can be scaled to higher throughput, and can be designed to report not only the presence but also the bioavailability of target substances. This chapter reviews available bacterial and eukaryotic whole-cell bioreporters for sensing organic pollutants and their applications in a variety of sample matrices. PMID:25084996

  4. Bioassay-based risk assessment of complex mixtures

    SciTech Connect

    Donnelly, K.C.; Safe, S.H.; Randerath, K.; Randerath, E.

    1994-12-31

    To compare the standard chemical-based risk assessment with in vitro genotoxicity assays, two complex environmental mixtures from a wood preserving site were analyzed in the Salmonella/microsome and E. coli prophage induction assays. Using GC/MS, sample 003 was found to contain relatively low levels of polycyclic aromatic hydrocarbons (PNAs) and elevated levels of polychlorinated dibenzo-p-dioxins (PCDDs), while sample 005 had higher levels of PNAs and relatively low levels of PCDDs. The complex mixtures were sequentially extracted with methylene chloride and methanol for analysis in Salmonella, or extracted with 1:1 hexane: acetone mixture for analysis in the prophage induction assay. At a dose of 1.0 mg/plate in Salmonella strain TA98 with metabolic activation, the methanol extract of sample 003 induced 197 net revertants, while sample 005 induced 436 net revertants. In the prophage induction assay, with activation, the hexane:acetone extract of sample 003 induced a fold increase that was slightly lower than that observed with sample 005. The estimated incremental carcinogenic risk for dermal adsorption and ingestion was 1.5E-3 for sample 003, while for sample 005 the estimated risk was 1.5E-2. Thus, the sample which induced the maximum response in both bioassays also had the highest estimated cancer risk. However, the frequency of PNA-DNA adducts in both skin and liver tissues was appreciably higher with sample 005 than with sample 003.

  5. Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays.

    SciTech Connect

    Anstey, Mitchell; Fruetel, Julia A.; Foster, Michael E.; Hayden, Carl C.; Buckley, Heather L.; Arnold, John

    2013-09-01

    Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves %22Click%22 chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

  6. Target organs in chronic bioassays of 533 chemical carcinogens.

    PubMed Central

    Gold, L S; Slone, T H; Manley, N B; Bernstein, L

    1991-01-01

    A compendium of carcinogenesis bioassay results organized by target organ is presented for 533 chemicals that are carcinogenic in at least one species. This compendium is based primarily on experiments in rats or mice; results in hamsters, nonhuman primates, and dogs are also reported. The compendium can be used to identify chemicals that induce tumors at particular sites, and to determine whether target sites are the same for chemicals positive in more than one species. The Carcinogenic Potency Database (CPDB), which includes results of 3969 experiments, is used in the analysis. The published CPDB includes details on each test, and literature references. Chemical carcinogens are reported for 35 different target organs in rats or mice. More than 80% of the carcinogens in each of these species are positive in at least one of the 8 most frequent target sites: liver, lung, mammary gland, stomach, vascular system, kidney, hematopoietic system, and urinary bladder. An analysis is presented of how well one can predict the carcinogenic response in mice from results in rats, or vice versa. Among chemicals tested in both species, 76% of rat carcinogens are positive in mice, and 71% of mouse carcinogens are positive in rats. Prediction is less accurate to the same target site: 52% of rat carcinogens are positive in the same site in mice, and 48% of mouse carcinogens are positive in the same site in rats. The liver is the most frequent site in common between rats and mice. PMID:1773795

  7. Bioassay-based risk assessment of complex mixtures

    SciTech Connect

    Donnelly, K.C.; Huebner, H.J.

    1996-12-31

    The baseline risk assessment often plays an integral role in various decision-making processes at Superfund sites. The present study reports on risk characterizations prepared for seven complex mixtures using biological and chemical analysis. Three of the samples (A, B, and C) were complex mixtures of polycyclic aromatic hydrocarbons (PAHs) extracted from coal tar; while four samples extracted from munitions-contaminated soil contained primarily nitroaromatic hydrocarbons. The chemical-based risk assessment ranked sample C as least toxic, while the risk associated with samples A and B was approximately equal. The microbial bioassay was in general agreement for the coal tar samples. The weighted activity of the coal tar extracts in Salmonella was 4,960 for sample C, and 162,000 and 206,000 for samples A and B, respectively. The bacterial mutagenicity of 2,4,6-trinitrotoluene contaminated soils exhibited an indirect correlation with chemical-based risk assessment. The aqueous extract of sample 004 induced 1,292 net revertants in Salmonella, while the estimated risk to ingestion and dermal adsorption was 2E-9. The data indicate that the chemical-based risk assessment accurately predicted the genotoxicity of the PAHs, while the accuracy of the risk assessment for munitions contaminated soils was limited due to the presence of metabolites of TNT degradation. The biological tests used in this research provide a valuable compliment to chemical analysis for characterizing the genotoxic risk of complex mixtures.

  8. Colorimetric paper bioassay for the detection of phenolic compounds.

    PubMed

    Alkasir, Ramiz S J; Ornatska, Maryna; Andreescu, Silvana

    2012-11-20

    A new type of paper based bioassay for the colorimetric detection of phenolic compounds including phenol, bisphenol A, catechol and cresols is reported. The sensor is based on a layer-by-layer (LbL) assembly approach formed by alternatively depositing layers of chitosan and alginate polyelectrolytes onto filter paper and physically entrapping the tyrosinase enzyme in between these layers. The sensor response is quantified as a color change resulting from the specific binding of the enzymatically generated quinone to the multilayers of immobilized chitosan on the paper. The color change can be quantified with the naked eye but a digitalized picture can also be used to provide more sensitive comparison to a calibrated color scheme. The sensor was optimized with respect to the number of layers, pH, enzyme, chitosan and alginate amounts. The colorimetric response was concentration dependent, with a detection limit of 0.86 (±0.1) μg/L for each of the phenolic compounds tested. The response time required for the sensor to reach steady-state color varied between 6 and 17 min depending on the phenolic substrate. The sensor showed excellent storage stability at room temperature for several months (92% residual activity after 260 days storage) and demonstrated good functionality in real environmental samples. A procedure to mass-produce the bioactive sensors by inkjet printing the LbL layers of polyelectrolyte and enzyme on paper is demonstrated. PMID:23113670

  9. USING BIOASSAYS TO EVALUATE THE PERFORMANCE OF EDC RISK MANAGEMENT METHODS

    EPA Science Inventory

    In Superfund risk management research, the performance of risk management techniques is typically evaluated by measuring "the concentrations of the chemicals of concern before and after risk management efforts. However, using bioassays and chemical data provides a more robust und...

  10. COMPARATIVE POTENCY OF COMPLEX MIXTURES: USE OF SHORT-TERM GENETIC BIOASSAYS IN CANCER RISK ASSESSMENT

    EPA Science Inventory

    The primary problem regarding the introduction of new energy sources is whether they will alter the mutagenicity, carcinogenicity and potential human cancer risk from combustion emissions. New risk assessment methodologies utilizing data from short-term bioassays, therefore, are ...

  11. IN SITU BIOASSAY CHAMBER FOR ASSESSMENT OF SEDIMENT TOXICITY AND BIOACCUMULATION USING BENTHIC INVERTEBRATES

    EPA Science Inventory

    In this study, we describe the construction of a simple, inexpensive bioassay chamber for testing sediment toxicity (survival and growth) and bioaccumulation under field conditions using the midge Chironomus tentans and the oligochaete Lumbriculus variegatus. The test chamber is ...

  12. DEVELOPMENT OF BIOASSAY PROCEDURES FOR DEFINING POLLUTION OF HARBOR SEDIMENTS. PART I

    EPA Science Inventory

    This research investigates bioassay methods which may be useful in assessing the degree of pollution of harbor sediments. Procedures studied include 96 hr. toxicity tests employing Hexagenia limbata, Daphnia magna and Pontoporeia affinis as biological probes, monitoring cough fre...

  13. CHARACTERIZING THE GENOTOXICITY OF HAZARDOUS INDUSTRIAL WASTES AND EFFLUENTS USING SHORT-TERM BIOASSAYS

    EPA Science Inventory

    This chapter demonstrates that short-term bioassays can reliably and expeditiously measure the genotoxic potential of hazardous industrial wastes and effluents. etrochemical wastes have been studied in detail, especially discharges from chemical manufacturing plants and textile a...

  14. EVALUATION OF THE MUTAGENICITY AND CARCINOGENICITY OF MOTOR VEHICLE EMISSIONS IN SHORT-TERM BIOASSAYS

    EPA Science Inventory

    Incomplete combustion of fuel in motor vehicles results in the emission of submicron carbonaceous particles which, after cooling and dilution, contain varying quantities of extractable organic constituents. These organics are mutagenic in bacteria. Confirmatory bioassays in mamma...

  15. Comparative susceptibility of bemisia tabaci to imidacloprid in field- and laboratory-based bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bemisia tabaci biotype B is a resistance-prone pest of protected and open agriculture. Systemic uptake bioassays used in resistance monitoring programs have provided important information on susceptibility to neonicotinoid insecticides, but have remained decoupled from field performance. Simultaneou...

  16. EVALUATION OF THREE FISH SPECIES AS BIOASSAY ORGANISMS FOR DREDGED MATERIAL TESTING

    EPA Science Inventory

    Three fish species, Cyprinodon variegatus, Fundulus similis, and Menidia menidia, were evaluated to determine which is most suitable as a bioassay organism for solid phase testing of dredged material. Acute toxicity and bioaccumulation of polychlorinated biphenyls (PCBs) were mon...

  17. Harmonia Axyridis Adults Avoid Catnip and Grapefruit-derived Terpenoids in Laboratory Bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We observed the avoidance behavior of the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), when adults were exposed to volatiles derived from catnip oil and grapefruit seed. In replicated laboratory bioassays, beetles avoided contact with volatiles emanating f...

  18. Evaluation of toxicity of selected insecticides against thrips on cotton in laboratory bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult vial technique (AVT) and spray table bioassays were conducted to evaluate toxicity of selected insecticides against immature and adult Western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). In AVT, technical insecticides comprising of organophosphates (d...

  19. NTP Toxicology and Carcinogenesis Studies of Pentachlorophenol (CAS NO. 87-86-5) in F344/N Rats (Feed Studies).

    PubMed

    1999-04-01

    Pentachlorophenol has been used as an herbicide, algicide, defoliant, wood preservative, germicide, fungicide, and molluscicide. Pentachlorophenol was nominated by the National Cancer Institute for carcinogenicity testing based on its widespread use as a wood preservative, potential for entering the environment (pentachlorophenol residues have been found worldwide in soil, water, and air samples; in food products; and in human and animal tissues and body fluids), and likelihood of bioaccumulation in the environment (pentachlorophenol is persistent in soil, having a half-life of up to 5 years). Technical Report No. 349 contains the results of the 2-year studies of pentachlorophenol performed by the NTP with B6C3F1 mice. Male and female F344/N rats were exposed to pentachlorophenol (approximately 99% pure) in feed for 28 days or 2 years. Genetic toxicology studies were conducted in vitro in Salmonella typhimurium and cultured Chinese hamster ovary cells and in vivo in rat and mouse bone marrow cells. 28-DAY STUDY IN RATS: Groups of 10 male and 10 female F344/N rats were given 0, 200, 400, 800, 1,600, or 3,200 ppm pentachlorophenol, equivalent to average daily doses of approximately 20, 40, 75, 150, or 270 mg pentachlorophenol/kg body weight to males and females in feed for 28 days. With the exception of one male and two females exposed to 3,200 ppm, all rats survived until the end of the study. The final mean body weights and body weight gains of male rats exposed to 1,600 or 3,200 ppm and female rats exposed to 400, 800, 1,600, or 3,200 ppm were significantly less than those of the controls; rats exposed to 3,200 ppm lost weight during the study. Feed consumption by 3,200 ppm males was less than that by the control group throughout the study. The absolute and relative liver weights of 400, 800, and 1,600 ppm males and all exposed groups of females were significantly greater than those of the controls. Compared to the control groups, the incidences of minimal to mild

  20. A Standardized Lepidopteran Bioassay to Investigate the Bioactivity of Insecticidal Proteins Produced in Transgenic Crops.

    PubMed

    Graser, Gerson; Walters, Frederick S

    2016-01-01

    Insecticidal bioassays are the only reliable method to investigate the biological activity of an insecticidal protein and therefore provide an essential toolkit for the characterization and potency determination of these proteins. Here we present a standardized method for a lepidopteran larval bioassay, which is optimized to specifically estimate activity of insecticidal proteins produced in transgenic plants. The treatment can be either applied to the surface of the artificial diet, or blended into the diet. PMID:26614295

  1. Issues in weighting bioassay data for use in regressions for internal dose assessments

    SciTech Connect

    Strom, D.J.

    1992-11-01

    For use of bioassay data in internal dose assessment, research should be done to clarify the goal desired, the choice of method to achieve the goal, the selection of adjustable parameters, and on the ensemble of information that is available. Understanding of these issues should determine choices of weighting factors for bioassay data used in regression models. This paper provides an assessment of the relative importance of the various factors.

  2. A simple, rapid bioassay for detecting effects of pollutants on bacteria

    SciTech Connect

    Bauer, N.J.; Seidler, R.J.; Knittel, M.D.

    1981-12-01

    A screening bioassay needs to be rapid, and sensitive. The bioassay is described which is accurate, inexpensive, and which utilizes bacteria as the toxicity predictor. The basis of the test involves measuring the kinetics of dissolved oxygen depletion by a mixed microbial population following exposure to a pollutant and allows results to be obtained in as little as 40 min. Pollutants tested were cadmium, copper, nickel, sulfate, diuron, pentachlorophenol, atrazine, tricholoracetic acid, dimethylformamide, and diazinon. (JMT)

  3. Application of root bioassays to detect nutrient deficiencies in fast-growing trees and agroforestry crops

    SciTech Connect

    Harrison, A.F.; Dighton, J.; Jones, H.E.

    1992-12-31

    A new method for the detection of nutrient deficiencies is outlined and recommended as an alternative to conventional soil and foliar analyses. Bioassays are conducted to measure the uptake and supply of the macronutrients. Examples are quoted of the successful use of this technique with Eucalyptus and Sitka spruce. The bioassays have been shown to give equally good results with a range of tree and ground crops.

  4. Laboratory for Atmospheres 2007 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Stewart, Richard W.

    2008-01-01

    The 2007 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  5. Laboratory for Atmospheres 2010 Technical Highlights

    NASA Technical Reports Server (NTRS)

    2011-01-01

    The 2010 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  6. Laboratory for Atmospheres 2009 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Cote, Charles E.

    2010-01-01

    The 2009 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  7. Laboratory for Atmospheres: 2006 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Stewart, Richard W.

    2007-01-01

    The 2006 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, are highlighted in this report.

  8. Laboratory for Atmospheres 2005 Technical Highlights

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The 2005 Technical highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  9. In situ bioassay using Chironomus riparius: An intermediate between laboratory and field sediment quality assessments

    SciTech Connect

    Guchte, C. van de; Grootelaar, L.; Naber, A.

    1995-12-31

    Benthic macroinvertebrates like chironomid larvae are important indicators for sediment quality. Both in field surveys and laboratory bioassays effect parameters like abundance, survival, growth, larval development and morphological abnormalities of chironomids are recommended biological endpoints to assess the impact of sediment associated contaminants. Now and then results from field surveys on contaminated sites appeared to differ from results in laboratory bioassays on sediment field samples from the same sites. The impact of so-called modifying factors like temperature, oxygen levels and the availability of food could be studied in the laboratory. However, these factors could not fully explain the observed differences. In situ bioassays have been developed to bridge the gap between laboratory and field derived data with respect to the exposure of cultured Chironomus riparius larvae versus field collected Chironomus sp. larvae. Control survival in the in situ bioassays was within acceptable limits (> 80%). Effects observed during the caged exposure of laboratory cultured first instar larvae at contaminated sites were in agreement with the hypothesis that adequate in-field bioassessment reduces uncertainties inherent in the use of standardized laboratory bioassays. Although relative risk ranking of chemicals or contaminated sites can rely upon standard testing protocols, in situ bioassays can give a better insight in exposure-effect relationships under actual field conditions.

  10. An overview of the PubChem BioAssay resource.

    PubMed

    Wang, Yanli; Bolton, Evan; Dracheva, Svetlana; Karapetyan, Karen; Shoemaker, Benjamin A; Suzek, Tugba O; Wang, Jiyao; Xiao, Jewen; Zhang, Jian; Bryant, Stephen H

    2010-01-01

    The PubChem BioAssay database (http://pubchem.ncbi.nlm.nih.gov) is a public repository for biological activities of small molecules and small interfering RNAs (siRNAs) hosted by the US National Institutes of Health (NIH). It archives experimental descriptions of assays and biological test results and makes the information freely accessible to the public. A PubChem BioAssay data entry includes an assay description, a summary and detailed test results. Each assay record is linked to the molecular target, whenever possible, and is cross-referenced to other National Center for Biotechnology Information (NCBI) database records. 'Related BioAssays' are identified by examining the assay target relationship and activity profile of commonly tested compounds. A key goal of PubChem BioAssay is to make the biological activity information easily accessible through the NCBI information retrieval system-Entrez, and various web-based PubChem services. An integrated suite of data analysis tools are available to optimize the utility of the chemical structure and biological activity information within PubChem, enabling researchers to aggregate, compare and analyze biological test results contributed by multiple organizations. In this work, we describe the PubChem BioAssay database, including data model, bioassay deposition and utilities that PubChem provides for searching, downloading and analyzing the biological activity information contained therein. PMID:19933261

  11. Using Highlighting to Train Attentional Expertise.

    PubMed

    Roads, Brett; Mozer, Michael C; Busey, Thomas A

    2016-01-01

    Acquiring expertise in complex visual tasks is time consuming. To facilitate the efficient training of novices on where to look in these tasks, we propose an attentional highlighting paradigm. Highlighting involves dynamically modulating the saliency of a visual image to guide attention along the fixation path of a domain expert who had previously viewed the same image. In Experiment 1, we trained naive subjects via attentional highlighting on a fingerprint-matching task. Before and after training, we asked subjects to freely inspect images containing pairs of prints and determine whether the prints matched. Fixation sequences were automatically scored for the degree of expertise exhibited using a Bayesian discriminative model of novice and expert gaze behavior. Highlighted training causes gaze behavior to become more expert-like not only on the trained images but also on transfer images, indicating generalization of learning. In Experiment 2, to control for the possibility that the increase in expertise is due to mere exposure, we trained subjects via highlighting of fixation sequences from novices, not experts, and observed no transition toward expertise. In Experiment 3, to determine the specificity of the training effect, we trained subjects with expert fixation sequences from images other than the one being viewed, which preserves coarse-scale statistics of expert gaze but provides no information about fine-grain features. Observing at least a partial transition toward expertise, we obtain only weak evidence that the highlighting procedure facilitates the learning of critical local features. We discuss possible improvements to the highlighting procedure. PMID:26744839

  12. Using Highlighting to Train Attentional Expertise

    PubMed Central

    Roads, Brett; Mozer, Michael C.; Busey, Thomas A.

    2016-01-01

    Acquiring expertise in complex visual tasks is time consuming. To facilitate the efficient training of novices on where to look in these tasks, we propose an attentional highlighting paradigm. Highlighting involves dynamically modulating the saliency of a visual image to guide attention along the fixation path of a domain expert who had previously viewed the same image. In Experiment 1, we trained naive subjects via attentional highlighting on a fingerprint-matching task. Before and after training, we asked subjects to freely inspect images containing pairs of prints and determine whether the prints matched. Fixation sequences were automatically scored for the degree of expertise exhibited using a Bayesian discriminative model of novice and expert gaze behavior. Highlighted training causes gaze behavior to become more expert-like not only on the trained images but also on transfer images, indicating generalization of learning. In Experiment 2, to control for the possibility that the increase in expertise is due to mere exposure, we trained subjects via highlighting of fixation sequences from novices, not experts, and observed no transition toward expertise. In Experiment 3, to determine the specificity of the training effect, we trained subjects with expert fixation sequences from images other than the one being viewed, which preserves coarse-scale statistics of expert gaze but provides no information about fine-grain features. Observing at least a partial transition toward expertise, we obtain only weak evidence that the highlighting procedure facilitates the learning of critical local features. We discuss possible improvements to the highlighting procedure. PMID:26744839

  13. Bioassay-directed fractionation and salmonella mutagenicity of automobile and forklift diesel exhaust particles.

    PubMed Central

    DeMarini, David M; Brooks, Lance R; Warren, Sarah H; Kobayashi, Takahiro; Gilmour, M Ian; Singh, Pramila

    2004-01-01

    Many pulmonary toxicity studies of diesel exhaust particles (DEPs) have used an automobile-generated sample (A-DEPs) whose mutagenicity has not been reported. In contrast, many mutagenicity studies of DEPs have used a forklift-generated sample (SRM 2975) that has been evaluated in only a few pulmonary toxicity studies. Therefore, we evaluated the mutagenicity of both DEPs in Salmonella coupled to a bioassay-directed fractionation. The percentage of extractable organic material (EOM) was 26.3% for A-DEPs and 2% for SRM 2975. Most of the A-EOM (~55%) eluted in the hexane fraction, reflecting the presence of alkanes and alkenes, typical of uncombusted fuel. In contrast, most of the SRM 2975 EOM (~58%) eluted in the polar methanol fraction, indicative of oxygenated and/or nitrated organics derived from combustion. Most of the direct-acting, base-substitution activity of the A-EOM eluted in the hexane/dichloromethane (DCM) fraction, but this activity eluted in the polar methanol fraction for the SRM 2975 EOM. The direct-acting frameshift mutagenicity eluted across fractions of A-EOM, whereas > 80% eluted only in the DCM fraction of SRM 2975 EOM. The A-DEPs were more mutagenic than SRM 2975 per mass of particle, having 227 times more polycyclic aromatic hydrocarbon-type and 8-45 more nitroarene-type mutagenic activity. These differences were associated with the different conditions under which the two DEP samples were generated and collected. A comprehensive understanding of the mechanisms responsible for the health effects of DEPs requires the evaluation of DEP standards for a variety of end points, and our results highlight the need for multidisciplinary studies on a variety of representative samples of DEPs. PMID:15175166

  14. Highlight area inpainting guided by illumination model

    NASA Astrophysics Data System (ADS)

    Wang, Yifan; Jiang, Zhiguo; Shi, Jun

    2014-01-01

    In this paper, we proposed a two-step algorithm based on the combination of the exemplar-based algorithm and the illumination model to deal with specular images, especially those contain saturated pixels in the highlight areas. First the proposed modified exemplar-based algorithm is employed to process the unsaturated specular pixels under the supervision of illumination model. Then we inpaint the rest regions in which the pixels are saturated with original exemplar-based algorithm to obtain the final result. Experimental results demonstrate that the proposed algorithm performs better on the images with saturated pixels in the highlight areas compared with classical highlight removal and image inpainting algorithms.

  15. Bioassay of thermal protection afforded by candidate flight suit fabrics.

    PubMed

    Knox, F S; Wachtel, T L; McCahan, G R

    1979-10-01

    The United States Army Aeromedical Research Laboratory (USAARL) porcine cutaneous bioassay technique was used to determine what mitigating effect four thermally protective flight suit fabrics would have on fire-induced skin damage. The fabrics were 4.8-ox twill weave Nomex aramide, 4.5-oz stabilized twill weave polybenzimidazole, 4.8-oz plain weave experimental high-temperature polymer (HT4), and 4.8-oz plain weave Nomex aramide (New Weave Nomex or NWN). Each fabric sample was assayed 20 times in each of four configurations: as a single layer in contact with the skin; as a single layer with a 6.35 mm (0.25 in) air gap between fabric and skin; in conjuction with a cotton T-shirt with no air gaps; and, finally, in conjuction with a T-shirt with a 6.35 mm air gap between T-shirt and fabric. Bare skin was used as a control. A JP-4 fueled furnace was used as a thermal source and was adjested to deliver a mean heat flux of 3.07 cal/cm2/s. The duration of exposure was 5 s. Four hundred burn sites were graded using clinical observation and microscopic techniques. Used as single layers, none of the fabrics demonstrated superiority in providing clinically significant protection. When used with a cotton T-shirt, protection was improved. Protection improved progressively for all fabrics and configuration when an air gap was introduced. The experimental high-temperature polymer consistently demonstrated lower heat flux transmission in all configurations, but did not significantly reduce clinical burns. PMID:518445

  16. [Bioassay for enrich-blood bioactivity of Agelicae Sinensis Radix].

    PubMed

    Wang, Xiao-xiao; Zhang, Li-hong; Li, Xi; Wang, Ye; Rong, Zu-yuan; Wei, Hong-ping; Song, Qi-rui; Lv, Guang-hua

    2015-04-01

    Danggui, Agelicae Sinensis Radix, is a widely used Chinese herb to enrich blood, but its quality cannot be effectively assessed by the known chemical markers such as ferulic acid, ligustilide, polysaccharides, etc. A new bioassay was therefore developed to quantify the Enrich-Blood Bioactivity (EBB) for the quality assessment of Danggui raw materials. Danggui sample was first extracted with ethanol and water, respectively. Then the ethanolic extract and water extract were mixed as a test sample to quantify the amount of EBB by mice experiment. The blood deficiency mode in mice was developed by intraperitoneal injecting cyclophospharmide and phenylhdrazine hydrochloride. The quantity of red blood cell was chosen as EBB marker. Cyclosporine A was chosen as a control substance. EBB in analytes was quantified by the amount reaction of parallel line analysis (3, 3') method. The results indicated that the reliability test for quantifying EBB was passed through and the measured value was valid. The analytes showed the significant EBB (P < 0.05). The correlation coefficient was 0.9984 (n=5) between the amount of cyclosporine A (0.035-0.56 g x kg(-1)) and the increased number of red blood cell. The relative standard deviation (RSY) on the amount of EBB was estimated to be 6.15% (n = 6) by six replicated tests, and the confidence limit rate was 26.68% (n = 6). Five Danggui samples, which were collected from different cultivation areas with various morphological characters, showed the variety of EBB in the range of 21.95-44.16 U x g(-1). It is concluded that the developed method is accurate to quantify the EBB of Danggui raw materials, and is therefore suitable to assess its quality. PMID:26281565

  17. Plasmonically amplified bioassay - Total internal reflection fluorescence vs. epifluorescence geometry.

    PubMed

    Hageneder, Simone; Bauch, Martin; Dostalek, Jakub

    2016-08-15

    This paper investigates plasmonic amplification in two commonly used optical configurations for fluorescence readout of bioassays - epifluorescence (EPF) and total internal reflection fluorescence (TIRF). The plasmonic amplification in the EPF configuration was implemented by using crossed gold diffraction grating and Kretschmann geometry of attenuated total reflection method (ATR) was employed in the TIRF configuration. Identical assay, surface architecture for analyte capture, and optics for the excitation, collection and detection of emitted fluorescence light intensity were used in both TIRF and EPF configurations. Simulations predict that the crossed gold diffraction grating (EPF) can amplify the fluorescence signal by a factor of 10(2) by the combination of surface plasmon-enhanced excitation and directional surface plasmon-coupled emission in the red part of spectrum. This factor is about order of magnitude higher than that predicted for the Kretschmann geometry (TIRF) which only took advantage of the surface plasmon-enhanced excitation. When applied for the readout of sandwich interleukin 6 (IL-6) immunoassay, the plasmonically amplified EPF geometry designed for Alexa Fluor 647 labels offered 4-times higher fluorescence signal intensity compared to TIRF. Interestingly, both geometries allowed reaching the same detection limit of 0.4pM despite of the difference in the fluorescence signal enhancement. This is attributed to inherently lower background of fluorescence signal for TIRF geometry compared to that for EPF which compensates for the weaker fluorescence signal enhancement. The analysis of the inflammation biomarker IL-6 in serum at medically relevant concentrations and the utilization of plasmonic amplification for the fluorescence measurement of kinetics of surface affinity reactions are demonstrated for both EPF and TIRF readout. PMID:27260457

  18. Episodic acidification of small streams in the northeastern united states: Fish mortality in field bioassays

    USGS Publications Warehouse

    Van Sickle, J.; Baker, J.P.; Simonin, H.A.; Baldigo, Barry P.; Kretser, W.A.; Sharpe, W.E.

    1996-01-01

    In situ bioassays were performed as part of the Episodic Response Project, to evaluate the effects of episodic stream acidification on mortality of brook trout (Salvelinus fontinalis) and forage fish species. We report the results of 122 bioassays in 13 streams of the three study regions: the Adirondack mountains of New York, the Catskill mountains of New York, and the Northern Appalachian Plateau of Pennsylvania. Bioassays during acidic episodes had significantly higher mortality than did bioassays conducted under nonacidic conditions, but there was little difference in mortality rates in bioassays experiencing acidic episodes and those experiencing acidic conditions throughout the test period. Multiple logistic regression models were used to relate bioassay mortality rates to summary statistics of time-varying stream chemistry (inorganic monomeric aluminum, calcium, pH, and dissolved organic carbon) estimated for the 20-d bioassay periods. The large suite of candidate regressors also included biological, regional, and seasonal factors, as well as several statistics summarizing various features of aluminum exposure duration and magnitude. Regressor variable selection and model assessment were complicated by multicol-linearity and overdispersion. For the target fish species, brook trout, bioassay mortality was most closely related to time-weighted median inorganic aluminum. Median Ca and minimum pH offered additional explanatory power, as did stream-specific aluminum responses. Due to high multicollinearity, the relative importance of different aluminum exposure duration and magnitude variables was difficult to assess, but these variables taken together added no significant explanatory power to models already containing median aluminum. Between 59 and 79% of the variation in brook trout mortality was explained by models employing between one and five regressors. Simpler models were developed for smaller sets of bioassays that tested slimy and mottled sculpin

  19. Optimization of an in vitro bioassay to monitor growth and formation of myotubes in real time.

    PubMed

    Murphy, Sylvia M; Kiely, Maeve; Jakeman, Philip M; Kiely, Patrick A; Carson, Brian P

    2016-06-01

    The importance of growth and maintenance of skeletal muscle is vital for long term health and quality of life. Appropriate nutrition with specific bioactivities relevant to the functionalities of tissues such as skeletal muscle, can assist in maintaining and promoting adaptive responses to biological and environmental stresses which prevent muscle atrophy and promote hypertrophy. The aim of this investigation was to develop a novel in vitro cell-based electric impedance assay to study myoblast to myotube formation on the real time cell analysis (RTCA) platform (xCELLigence™, ACEA) and to validate the system by testing myotube responses to hypertrophic stimuli. C2C12 myoblasts were proliferated until 70% confluent in Dulbecco's Modified Eagles Medium (DMEM) (10% FBS) and subsequently differentiated to myotubes over 8 days in DMEM [2% horse serum (HS)]. Changes in cell behaviour and adhesion properties were monitored by measuring impedance via interdigitated microelectrodes in the base of E-16 cell culture dishes. To establish the suitability of this assay to monitor nutrient regulation of muscle hypertrophy, leucine, a known potent regulator of MPS was then supplemented to the fully formed myotubes in physiologically relevant conditions-0.20 mM, 0.40 mM, 0.6 mM, 0.8 mM and above 1.0 mM, 1.5 mM, 2.0 mM and impedance subsequently monitored. Parallel experiments highlighting alterations in myotube thickness, muscle protein synthesis (MPS) (mammalian target of rapamycin; mTOR) and differentiation (myogenin) were conducted to support RTCA bioassay findings. This in vitro bioassay can be used to monitor skeletal muscle behaviour and identify nutrient compounds with bioactivities promoting skeletal muscle hypertrophy, reducing muscle atrophy and thus inform the development of novel nutrient formulations for the maintenance of skeletal muscle. PMID:27009307

  20. Optimization of an in vitro bioassay to monitor growth and formation of myotubes in real time

    PubMed Central

    Murphy, Sylvia M.; Kiely, Maeve; Jakeman, Philip M.; Kiely, Patrick A.; Carson, Brian P.

    2016-01-01

    The importance of growth and maintenance of skeletal muscle is vital for long term health and quality of life. Appropriate nutrition with specific bioactivities relevant to the functionalities of tissues such as skeletal muscle, can assist in maintaining and promoting adaptive responses to biological and environmental stresses which prevent muscle atrophy and promote hypertrophy. The aim of this investigation was to develop a novel in vitro cell-based electric impedance assay to study myoblast to myotube formation on the real time cell analysis (RTCA) platform (xCELLigence™, ACEA) and to validate the system by testing myotube responses to hypertrophic stimuli. C2C12 myoblasts were proliferated until 70% confluent in Dulbecco's Modified Eagles Medium (DMEM) (10% FBS) and subsequently differentiated to myotubes over 8 days in DMEM [2% horse serum (HS)]. Changes in cell behaviour and adhesion properties were monitored by measuring impedance via interdigitated microelectrodes in the base of E-16 cell culture dishes. To establish the suitability of this assay to monitor nutrient regulation of muscle hypertrophy, leucine, a known potent regulator of MPS was then supplemented to the fully formed myotubes in physiologically relevant conditions–0.20 mM, 0.40 mM, 0.6 mM, 0.8 mM and above 1.0 mM, 1.5 mM, 2.0 mM and impedance subsequently monitored. Parallel experiments highlighting alterations in myotube thickness, muscle protein synthesis (MPS) (mammalian target of rapamycin; mTOR) and differentiation (myogenin) were conducted to support RTCA bioassay findings. This in vitro bioassay can be used to monitor skeletal muscle behaviour and identify nutrient compounds with bioactivities promoting skeletal muscle hypertrophy, reducing muscle atrophy and thus inform the development of novel nutrient formulations for the maintenance of skeletal muscle. PMID:27009307

  1. Highlights from NNSA's Decade of Success

    ScienceCinema

    None

    2010-09-01

    On April 28, 2010, the National Nuclear Security Administration celebrated its 10-year anniversary with a series of events aimed at highlighting a decade of success across the nuclear security enterprise. This slideshow features images from the past 10 years.

  2. Highlights of the 2009 Hurricane Season

    NASA Video Gallery

    Picture yourself sitting in space watching the highlights of the 2009's Atlantic Ocean hurricane season in fast-forward. This latest animation from NASA and the National Oceanic and Atmospheric Adm...

  3. Highlights from NNSA's Decade of Success

    SciTech Connect

    2010-04-28

    On April 28, 2010, the National Nuclear Security Administration celebrated its 10-year anniversary with a series of events aimed at highlighting a decade of success across the nuclear security enterprise. This slideshow features images from the past 10 years.

  4. EuroEcho-Imaging 2015: highlights.

    PubMed

    Magne, Julien; Popescu, Bogdan A; Cosyns, Bernard; Donal, Erwan; Miller, Owen; Neglia, Danilo; Plein, Sven; Lancellotti, Patrizio; Habib, Gilbert

    2016-06-01

    The annual meeting of the European Association of Cardiovascular Imaging, EuroEcho-Imaging, was held in Seville, Spain, in December 2015. In the present paper, we present a summary of the 'Highlights' session. PMID:27099280

  5. The Limits of Two-Year Bioassay Exposure Regimens for Identifying Chemical Carcinogens

    PubMed Central

    Huff, James; Jacobson, Michael F.; Davis, Devra Lee

    2008-01-01

    Background Chemical carcinogenesis bioassays in animals have long been recognized and accepted as valid predictors of potential cancer hazards to humans. Most rodent bioassays begin several weeks after birth and expose animals to chemicals or other substances, including workplace and environmental pollutants, for 2 years. New findings indicate the need to extend the timing and duration of exposures used in the rodent bioassay. Objectives In this Commentary, we propose that the sensitivity of chemical carcinogenesis bio-assays would be enhanced by exposing rodents beginning in utero and continuing for 30 months (130 weeks) or until their natural deaths at up to about 3 years. Discussion Studies of three chemicals of different structures and uses—aspartame, cadmium, and toluene—suggest that exposing experimental animals in utero and continuing exposure for 30 months or until their natural deaths increase the sensitivity of bioassays, avoid false-negative results, and strengthen the value and validity of results for regulatory agencies. Conclusions Government agencies, drug companies, and the chemical industry should conduct and compare the results of 2-year bioassays of known carcinogens or chemicals for which there is equivocal evidence of carcinogenicity with longer-term studies, with and without in utero exposure. If studies longer than 2 years and/or with in utero exposure are found to better identify potential human carcinogens, then regulatory agencies should promptly revise their testing guidelines, which were established in the 1960s and early 1970s. Changing the timing and dosing of the animal bioassay would enhance protection of workers and consumers who are exposed to potentially dangerous workplace or home contaminants, pollutants, drugs, food additives, and other chemicals throughout their lives. PMID:19057693

  6. Benchmarking organic micropollutants in wastewater, recycled water and drinking water with in vitro bioassays.

    PubMed

    Escher, Beate I; Allinson, Mayumi; Altenburger, Rolf; Bain, Peter A; Balaguer, Patrick; Busch, Wibke; Crago, Jordan; Denslow, Nancy D; Dopp, Elke; Hilscherova, Klara; Humpage, Andrew R; Kumar, Anu; Grimaldi, Marina; Jayasinghe, B Sumith; Jarosova, Barbora; Jia, Ai; Makarov, Sergei; Maruya, Keith A; Medvedev, Alex; Mehinto, Alvine C; Mendez, Jamie E; Poulsen, Anita; Prochazka, Erik; Richard, Jessica; Schifferli, Andrea; Schlenk, Daniel; Scholz, Stefan; Shiraishi, Fujio; Snyder, Shane; Su, Guanyong; Tang, Janet Y M; van der Burg, Bart; van der Linden, Sander C; Werner, Inge; Westerheide, Sandy D; Wong, Chris K C; Yang, Min; Yeung, Bonnie H Y; Zhang, Xiaowei; Leusch, Frederic D L

    2014-01-01

    Thousands of organic micropollutants and their transformation products occur in water. Although often present at low concentrations, individual compounds contribute to mixture effects. Cell-based bioassays that target health-relevant biological endpoints may therefore complement chemical analysis for water quality assessment. The objective of this study was to evaluate cell-based bioassays for their suitability to benchmark water quality and to assess efficacy of water treatment processes. The selected bioassays cover relevant steps in the toxicity pathways including induction of xenobiotic metabolism, specific and reactive modes of toxic action, activation of adaptive stress response pathways and system responses. Twenty laboratories applied 103 unique in vitro bioassays to a common set of 10 water samples collected in Australia, including wastewater treatment plant effluent, two types of recycled water (reverse osmosis and ozonation/activated carbon filtration), stormwater, surface water, and drinking water. Sixty-five bioassays (63%) showed positive results in at least one sample, typically in wastewater treatment plant effluent, and only five (5%) were positive in the control (ultrapure water). Each water type had a characteristic bioanalytical profile with particular groups of toxicity pathways either consistently responsive or not responsive across test systems. The most responsive health-relevant endpoints were related to xenobiotic metabolism (pregnane X and aryl hydrocarbon receptors), hormone-mediated modes of action (mainly related to the estrogen, glucocorticoid, and antiandrogen activities), reactive modes of action (genotoxicity) and adaptive stress response pathway (oxidative stress response). This study has demonstrated that selected cell-based bioassays are suitable to benchmark water quality and it is recommended to use a purpose-tailored panel of bioassays for routine monitoring. PMID:24369993

  7. Escherichia coli DnaB Helicase–DnaC Protein Complex: Allosteric Effects of the Nucleotides on the Nucleic Acid Binding and the Kinetic Mechanism of NTP Hydrolysis. 3†

    PubMed Central

    Roychowdhury, Anasuya; Szymanski, Michal R.; Jezewska, Maria J.; Bujalowski, Wlodzimierz

    2011-01-01

    Allosteric interactions between the DNA- and NTP-binding sites of the Escherichia coli DnaB helicase engaged in the DnaB–DnaC complex and the mechanism of NTP hydrolysis by the complex have been examined using the fluorescence titration, analytical ultracentrifugation, and rapid quench-flow technique. Surprisingly, the ssDNA affinity of the DnaB–DnaC complex is independent of the structure of the phosphate group of the cofactor bound to the helicase. Thus, the DnaC protein eliminates the antagonistic allosteric effect of NTP and NDP on the ssDNA affinity of the enzyme. The protein changes the engagement of the DNA-binding subsites of the helicase in interactions with the nucleic acid, depending on the structure of the phosphate group of the present nucleotide cofactor and profoundly affects the structure of the bound DNA. Moreover, the ssDNA affinity of the helicase in the DnaB–DnaC complex is under the control of the nucleotide-binding site of the DnaC protein. The protein does not affect the NTP hydrolysis mechanism of the helicase. Nevertheless, the rate of the chemical step is diminished in the DnaB–DnaC complex. In the tertiary DnaB–DnaC–ssDNA complex, the ssDNA changes the internal dynamics between intermediates of the pyrimidine cofactor, in a manner independent of the base composition of the DNA, while the hydrolysis step of the purine cofactor is specifically stimulated by the homoadenosine ssDNA. The significance of these results for functional activities of the DnaB–DnaC complex is discussed. PMID:19432487

  8. Reading disc-based bioassays with standard computer drives.

    PubMed

    Yu, Hua-Zhong; Li, Yunchao; Ou, Lily M-L

    2013-02-19

    -based bioassays quantitatively. In this Account, we first provide a brief introduction to CD-related materials chemistry and microfluidics research. Then we describe the mild chemistry developed in our laboratory for the preparation of computer-readable biomolecular screening assays: photochemical activation of the polycarbonate (PC) disc surface and immobilization and delivery of probe and target biomolecules. We thoroughly discuss the analysis of the molecular recognition events: researchers can "read" these devices quantitatively with an unmodified optical drive of any personal computer. Finally, and critically, we illustrate our digitized molecular diagnosis approach with three trial systems: DNA hybridization, antibody-antigen binding, and ultrasensitive lead detection with a DNAzyme assay. These examples demonstrate the broad potential of this new analytical/diagnostic tool for medical screening, on-site food/water safety testing, and remote environmental monitoring. PMID:23025412

  9. Monitoring Cyp2b10 mRNA expression at cessation of 2-year carcinogenesis bioassay in mouse liver provides evidence for a carcinogenic mechanism devoid of human relevance: The dalcetrapib experience

    SciTech Connect

    Hoflack, J-C.; Mueller, L. Fowler, S.; Braendli-Baiocco, A.; Flint, N.; Kuhlmann, O.; Singer, T.; Roth, A.

    2012-03-15

    Introduction: Dalcetrapib is a cholesteryl ester transfer protein (CETP) modulator in clinical assessment for cardiovascular outcome benefits. In compliance with regulatory requirements, dalcetrapib was evaluated in rodent 2-year carcinogenesis bioassays. In the mouse bioassay, male mice demonstrated increased liver weight and statistically increased incidences of hepatocellular adenoma/carcinoma. Hepatic cytochrome p450 (Cyp) 2b10 mRNA induction and increased Cyp2b10 enzyme activity signify activation of hepatic nuclear receptor constitutive androstane receptor (CAR), a widely established promoter of rodent-specific hepatic tumors. We therefore monitored hepatic Cyp2b10 mRNA and its enzyme activity in a subset of dalcetrapib-treated male mice from the bioassay. Methods: Liver samples were obtained from ∼ 1/3 of male mice from each dose group including vehicle-controls (mean and earliest study day of death 678 and 459 respectively). Quantitative real time PCR (qRT-PCR) was performed to determine Cyp2b10 mRNA expression and Cyp1a-, Cyp2b10- and Cyp3a-selective activities were monitored. Results: Cyp2b10 mRNA was strongly induced by dalcetrapib with an expected wide inter-individual variation (5–1421-fold). Group average fold-induction versus vehicle-controls showed a dose-related increase from 48-fold (250 mg/kg/day) to 160-fold (750 mg/kg/day), which declined slightly at 2000 mg/kg/day (97-fold). Cyp enzyme activities showed approximate doubling of total Cyp P450 content per milligram protein and a 9-fold increase in Cyp2b10-selective pentoxyresorufin O-dealkylase activity (750 mg/kg/day). Discussion: These data from hepatic Cyp2b10 monitoring are strongly suggestive of CAR activation by dalcetrapib, a mechanism devoid of relevance towards hepatocarcinogenesis in humans; results show feasibility of Cyp2b10 as a surrogate marker for this mechanism at cessation of a carcinogenesis bioassay. -- Highlights: ► Liver tumors were induced in male mice by dalcetrapib

  10. The usefulness of a sediment bioassay with the gastropod Nassarius reticulatus in tributyltin monitoring programs.

    PubMed

    Laranjeiro, Filipe; Pérez, Sara; Navarro, Patricia; Carrero, José Antonio; Beiras, Ricardo

    2015-11-01

    Despite the use of tributyltin (TBT) had been banned worldwide in 2008 there is still evidence of its deleterious presence in environment. We evaluate the usefulness of a 28days sediment bioassay with Nassarius reticulatus females to monitor TBT pollution, using imposex as endpoint. In addition, butyltins were determined in sediments and tissues, and, whenever posible, imposex was assessed in native N. reticulatus at the same sites where sediments were sampled. In the bioassay, a significant increase in imposex parameters was obtained with three sediments (Vi2, Vi3, and Vi4). No correlation was found between this and TBT concentrations in sediment although good correlations were obtained for TBT in tissues, putting in evidence TBT bioavailability in sediment. A significant decrease in imposex from 2008 to 2013 in native snails was only observed at sites that did not cause any effect in the bioassay. In contrast, imposex levels in 2013 were kept as high as 2008 in one of the sites where a significant imposex increase in the bioassay was observed. The bioassay proves thus to be a practical and ecological relevant tool, as: (i) it can be conducted in sites with no native populations of snails, (ii) it provides early identification of polluted sites, anticipating future imposex levels or early identification of recovering, and (iii) it yields information on the bioavailable fraction of the TBT in the sediment. Therefore, this tool can be of extreme usefulness under the scope of recent European legislative frameworks. PMID:26318117

  11. Rainbow trout cell bioassay-derived relative potencies for halogenated aromatic hydrocarbons: Comparison and sensitivity analysis

    SciTech Connect

    Villeneuve, D.L.; Blankenship, A.L.; Giesy, J.P.; Richter, C.A.

    1999-05-01

    Rainbow trout hepatoma cells, stably transfected with a luciferase reporter gene under control of dioxin-responsive elements (RLT 2.0 cells) were used to derive relative potencies (RPs) for a variety of halogenated aromatic hydrocarbons (HAHs) that are structurally similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). This in vitro bioassay utilizes 96-well microplates, which provide high sample throughput and assay efficiency without affecting sensitivity. The RLT 2.0-derived potencies for dioxin and furan congeners, relative to 2,3,7,8-TCDD, ranged from 0.917 for 1,2,3,4,7,8-hexachlorodibenzofuran to 0.208 or 1,2,3,7,8-pentachlorodibenzofuran. All mono- and di-ortho polychlorinated biphenyls (PCBs) tested had RPs that were orders of magnitude less than TCDD, but point estimates could not be determined. The RLT 2.0-derived RPs were found to be comparable to both other rainbow trout-specific RPs and RPs based on mammalian bioassays. Sensitivity analysis suggested that the range of uncertainty associated with TCDD equivalent (TEQ) estimates based on RLT 2.0-derived RPs is approximately 10-fold. Within this degree of uncertainty and the context of this study, the RLT 2.0 bioassay showed no definitive biases or inaccuracies relative to similar mammalian- or fish-specific in vitro bioassays. Thus, the RLT 2.0 bioassay appears to be a useful tool for evaluating dioxin-like potency of HAHs to fish.

  12. Selecting a sensitive battery of bioassays to detect toxic effects of metals in effluents.

    PubMed

    de Paiva Magalhães, Danielly; da Costa Marques, Mônica Regina; Fernandes Baptista, Darcilio; Forsin Buss, Daniel

    2014-09-01

    The use of bioassay batteries is necessary to evaluate toxic effects at various biological levels. The selection of bioassays without prior testing and determination of the most sensitive/suitable groups for each impact may allow the discharge of effluents that pose a threat to the environment. The present study tested and selected a battery of sensitive ecotoxicological bioassays for detecting toxic effects of metals. The sensitivities of six organisms were evaluated (algae Pseudokirchneriella subcapitata and Chlorella vulgaris, Cladocera Daphnia similis and Ceriodaphnia dubia, and fish Poecilia reticulata and Danio rerio) after exposure to 10 individual metal species deemed toxic to the aquatic environment (Ag(+), Cd(2+), Cu(+), Cu(2+), Cr(3+), Cr(6+), Pb(2+), Ni(2+), Zn(2+), and Hg(2+)) and to real (steel-mill) and laboratory simulated effluents. In the bioassays, fish were the least sensitive; D. rerio showed no sensitivity to any of the effluents tested. P. subcapitata was a good bioindicator of Cr(3+) toxicity, and D. similis was the most sensitive organism to Hg(2+); but the toxic effect of effluents with higher levels of Hg(2+) was better detected by C. dubia. The most sensitive battery of bioassays to detect low concentrations of dissolved metals in effluents was the 72-h chronic test with C. vulgaris and the 48-h acute test with C. dubia. PMID:25199585

  13. Characterization of chemical waste site contamination and its extent using bioassays

    SciTech Connect

    Thomas, J.M.; Callahan, C.A.; Cline, J.F.; Greene, J.C.; McShane, M.C.; Miller, W.E.; Peterson, S.A.; Simpson, J.C.; Skalski, J.R.

    1984-12-01

    Bioassays were used in a three-phase research project to assess the comparative sensitivity of test organisms to known chemicals, determine if the chemical components in field soil and water samples containing unknown contaminants could be inferred from our laboratory studies using known chemicals, and to investigate kriging (a relatively new statistical mapping technique) and bioassays as methods to define the areal extent of chemical contamination. The algal assay generally was most sensitive to samples of pure chemicals, soil elutriates and water from eight sites with known chemical contamination. Bioassays of nine samples of unknown chemical composition from the Rocky Mountain Arsenal (RMA) site showed that a lettuce seed soil contact phytoassay was most sensitive. In general, our bioassays can be used to broadly identify toxic components of contaminated soil. Nearly pure compounds of insecticides and herbicides were less toxic in the sensitive bioassays than were the counterpart commercial formulations. This finding indicates that chemical analysis alone may fail to correctly rate the severity of environmental toxicity. Finally, we used the lettuce seed phytoassay and kriging techniques in a field study at RMA to demonstrate the feasibility of mapping contamination to aid in cleanup decisions. 25 references, 9 figures, 9 tables.

  14. Studies on the bioassayable growth hormone-like activity of plasma

    NASA Technical Reports Server (NTRS)

    Ellis, S.; Vodian, M. A.; Grindeland, R. E.

    1978-01-01

    Evidence supporting the existence of bioassayable growth hormone-like activity in blood plasma distinct from the growth hormone measurable by radioimmunoassay and from somatomedin is presented. Tibial assays of the growth-hormone-like activity of injected, concentrated normal human and rat plasma in hypophysectomized rats reveal 200- and 50-fold activity excesses, respectively, with respect to the amount of growth hormone detected by radioimmunoassay. The origin of this bioassayable plasma hormone has been localized to the region of the pituitary, the origin of growth hormone, a distribution not followed by somatomedin C. Purification of the bioassayable agent indicates that is has a molecular weight of between 60,000 and 80,000, in contrast to that of growth hormone (20,000), and that the bioassayable activity is distinct from that of somatomedin C. Growth hormone-like activity detected in Cohn fraction IV as well as plasma activity, are found to be collectable on Dowex 50 resin, in contrast to somatomedin C and nonsuppressible insulin-like activity. The formation of bioassayable growth hormone-activity agents from radioimmunoassayable growth hormone and directly in the pituitary is suggested.

  15. Bioaccumulation of organic chemicals in contaminated soils: evaluation of bioassays with earthworms.

    PubMed

    Jager, Tjalling; van der Wal, Leon; Fleuren, Roel H L J; Barendregt, Arjan; Hermens, Joop L M

    2005-01-01

    Earthworms live in close contact with the soil and can thus be considered representative for the bioavailability of chemicals at contaminated sites. Bioavailability can either be assessed by analyzing earthworms from contaminated locations or by exposing laboratory-reared specimens to soil samples from the field (bioassays). In this study, we investigate the relevance of bioassays by using an extended experimental design (to identify signs of depletion of the bioavailable phase by the earthworms) and by using two species of earthworm (the standard test species Eisenia andrei and the field-relevant Aporrectodea caliginosa). Furthermore, bioassay results are compared to body residues of worms collected from the field site: a heavily polluted polder, amended with dredge spoil. We focused on telodrin, dieldrin, hexachlorobenzene, and eight PCBs. With our bioassay design, it was shown that depletion was unlikely, although more subtle effects could have occurred (e.g., changes in sorption during the experiments). E. andrei is a good choice for bioassays because its body residues correlate well to those in A. caliginosa, as well as to those in the field-collected worms. Nevertheless, E. andrei accumulated slightly more than the other species and appeared to be more sensitive to the conditions in soil from one of our sites. PMID:15667108

  16. Display format, highlight validity, and highlight method: Their effects on search performance

    NASA Technical Reports Server (NTRS)

    Donner, Kimberly A.; Mckay, Tim D.; Obrien, Kevin M.; Rudisill, Marianne

    1991-01-01

    Display format and highlight validity were shown to affect visual display search performance; however, these studies were conducted on small, artificial displays of alphanumeric stimuli. A study manipulating these variables was conducted using realistic, complex Space Shuttle information displays. A 2x2x3 within-subjects analysis of variance found that search times were faster for items in reformatted displays than for current displays. Responses to valid applications of highlight were significantly faster than responses to non or invalidly highlighted applications. The significant format by highlight validity interaction showed that there was little difference in response time to both current and reformatted displays when the highlight validity was applied; however, under the non or invalid highlight conditions, search times were faster with reformatted displays. A separate within-subject analysis of variance of display format, highlight validity, and several highlight methods did not reveal a main effect of highlight method. In addition, observed display search times were compared to search time predicted by Tullis' Display Analysis Program. Benefits of highlighting and reformatting displays to enhance search and the necessity to consider highlight validity and format characteristics in tandem for predicting search performance are discussed.

  17. Brookhaven highlights, October 1979-September 1980

    SciTech Connect

    Not Available

    1980-01-01

    Highlights are given for the research areas of the Brookhaven National Laboratory. These areas include high energy physics, physics and chemistry, life sciences, applied energy science (energy and environment, and nuclear energy), and support activities (including mathematics, instrumentation, reactors, and safety). (GHT)

  18. Highlights from Education at a Glance 2010

    ERIC Educational Resources Information Center

    OECD Publishing (NJ3), 2010

    2010-01-01

    "Highlights from Education at a Glance 2010" is a companion publication to the OECD's flagship compendium of education statistics, Education at a Glance. It provides easily accessible data on key topics in education today, including: education levels and student numbers, economic and social benefits of education, education spending, the school…

  19. Highlights on DESD Progress to Date

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific and Cultural Organization (UNESCO), 2007

    2007-01-01

    This brief report, delivered after the completion of the 1st year of the United Nations (UN) Decade of Education for Sustainable Development (DESD) (2005-2014), highlights the recent developments regarding the Decade (2005). It reports on the documents prepared, the regional and national launches of the Decade held so far and presents relevant…

  20. The Nation's Report Card: Mathematics Highlights, 2003.

    ERIC Educational Resources Information Center

    National Center for Education Statistics (ED), Washington, DC.

    This issue of The Nation's Report Card highlights mathematics in 2003. It includes sections on Average Scale Scores, Students Reaching NAEP Achievement Levels, Percentile Results, 2003 Assessment Design, State Results, Subgroup Results, Sample Mathematics Questions, Technical Notes, Additional Data Tables, and NAEP on the Web. (AMT)

  1. PARTICULATE CONTROL HIGHLIGHTS: FINE PARTICLE SCRUBBER RESEARCH

    EPA Science Inventory

    The report gives highlights of fine particle scrubber research performed by, or under the direction of, EPA's Industrial Environmental Research Laboratory (IERL-RTP) at Research Triangle Park, North Carolina. The U.S. EPA has been actively involved in research and development in ...

  2. LibTech Highlights from ALA Midwinter

    ERIC Educational Resources Information Center

    Hane, Paula J.

    2009-01-01

    Despite lower attendance than in the past and blustery, cold weather, the American Library Association's Midwinter Meeting in Denver in January offered lots of news from industry vendors and lots of opportunities to discuss important issues and trends. In this report, the author highlights some of the most important product announcements with a…

  3. The Nation's Report Card: Science Highlights 2000.

    ERIC Educational Resources Information Center

    Education Statistics Quarterly, 2001

    2001-01-01

    Presents highlights from the National Assessment of Educational Progress (NAEP) 2000 Science Assessment, including average scores and achievement-level performance at the national and state levels. Results show no change in national average scores at grades 4 and 8 and a decline at grade 12, with few changes overall in students' 2000 achievement…

  4. Brookhaven highlights - Brookhaven National Laboratory 1995

    SciTech Connect

    1996-09-01

    This report highlights research conducted at Brookhaven National Laboratory in the following areas: alternating gradient synchrotron; physics; biology; national synchrotron light source; department of applied science; medical; chemistry; department of advanced technology; reactor; safety and environmental protection; instrumentation; and computing and communications.

  5. Highlights from AQMEII Phase 2 & Next Steps

    EPA Science Inventory

    We present highlights of the results obtained in the second phase of the Air Quality Model Evaluation International Initiative (AQMEII) that was completed in May 2014. Activities in this phase were focused on the application and evaluation of coupled meteorology-chemistry models ...

  6. Education at a Glance 2011: Highlights

    ERIC Educational Resources Information Center

    OECD Publishing (NJ1), 2011

    2011-01-01

    "Education at a Glance 2011: Highlights" offers a reader-friendly introduction to the Organisation for Economic Cooperation and Development's (OECD's) collection of internationally comparable data on education. As the name suggests, it is derived from "Education at a Glance 2011", the OECD's flagship compendium of education statistics. However, it…

  7. Education at a Glance 2012: Highlights

    ERIC Educational Resources Information Center

    OECD Publishing (NJ3), 2012

    2012-01-01

    "Education at a Glance 2012: Highlights" offers a reader-friendly introduction to the Organisation for Economic Cooperation and Development's (OECD's) collection of internationally comparable data on education. As the name suggests, it is derived from "Education at a Glance 2012", the OECD's flagship compendium of education statistics. However, it…

  8. EM international activities. February 1997 highlights

    SciTech Connect

    1997-02-01

    EM International Highlights is a brief summary of on-going international projects within the Department of Energy`s Office of Environmental Management (EM). This document contains sections on: Global Issues, activities in Western Europe, activities in central and Eastern Europe, activities in Russia, activities in Asia and the Pacific Rim, activities in South America, activities in North America, and International Organizations.

  9. Strategies for Transferring Mixtures of Organic Contaminants from Aquatic Environments into Bioassays.

    PubMed

    Jahnke, Annika; Mayer, Philipp; Schäfer, Sabine; Witt, Gesine; Haase, Nora; Escher, Beate I

    2016-06-01

    Mixtures of organic contaminants are ubiquitous in the environment. Depending on their persistence and physicochemical properties, individual chemicals that make up the mixture partition and distribute within the environment and might then jointly elicit toxicological effects. For the assessment and monitoring of such mixtures, a variety of cell-based in vitro and low-complexity in vivo bioassays based on algae, daphnids or fish embryos are available. A very important and sometimes unrecognized challenge is how to combine sampling, extraction and dosing to transfer the mixtures from the environment into bioassays, while conserving (or re-establishing) their chemical composition at adjustable levels for concentration-effect assessment. This article outlines various strategies for quantifiable transfer from environmental samples including water, sediment, and biota into bioassays using total extraction or polymer-based passive sampling combined with either solvent spiking or passive dosing. PMID:26804122

  10. Bioassay, isolation and studies on the mechanism of action of neurite extension factor

    NASA Technical Reports Server (NTRS)

    Kligman, D.

    1984-01-01

    The identification and purification of molecules active in promoting neurite outgrowth requires a sensitive reproducible bioassay. A quantitative bioassay was utilized to purify a neurite extension factor (NEF) based on counting the number of phase bright neurons with processes at least equal to one cell body diameter after 20 hrs. in culture is defined, serum free medium. Using a combination of heat treatment DEAE cellulose chromatography and gel filtration, an acidic protein of M sub r = 75,000 was highly purified. Upon reduction, it yields subunits of M sub r = 37,000. Purified fractions are active half maximally at 100 ng/ml in inducing neurite outgrowth in this bioassay. Currently, monoclonal antibodies to NEF are being produced. Female Balb C mice were immunized with the antigen and fusions with mouse myeloma cells will be performed to yield hybridoma cells.

  11. Comparison of liquid chromatographic and bioassay procedures for determining depletion of intramuscularly injected tylosin.

    PubMed

    Moats, W A; Harris, E W; Steele, N C

    1985-01-01

    Crossbred pigs weighing 80-110 kg were injected intramuscularly in the ham with 8.8 mg/kg tylosin. Animals were slaughtered in groups of 3 at intervals of 4 h, and 1, 2, 4, and 8 days after injection, and samples of blood, injected muscle, uninjected muscle, liver, and kidney were analyzed by liquid chromatography (LC) and by bioassay using Sarcina lutea as the test organism. The LC method was far more sensitive with a detection limit of less than 0.1 ppm, while the detection limit by bioassay was about 0.5 ppm in tissue. Results by bioassay and LC sometimes differed considerably for tissue samples. Residues in all tissues were below the tolerance limit of 0.2 ppm at 24 h, except in the injected muscle in one animal. Residues were not detected in any tissue of any animal at 48 h after treatment. PMID:4019360

  12. Bioassay for estimating the biogenic methane-generating potential of coal samples

    USGS Publications Warehouse

    Jones, E.J.P.; Voytek, M.A.; Warwick, P.D.; Corum, M.D.; Cohn, A.; Bunnell, J.E.; Clark, A.C.; Orem, W.H.

    2008-01-01

    Generation of secondary biogenic methane in coal beds is likely controlled by a combination of factors such as the bioavailability of coal carbon, the presence of a microbial community to convert coal carbon to methane, and an environment supporting microbial growth and methanogenesis. A set of treatments and controls was developed to bioassay the bioavailability of coal for conversion to methane under defined laboratory conditions. Treatments included adding a well-characterized consortium of bacteria and methanogens (enriched from modern wetland sediments) and providing conditions to support endemic microbial activity. The contribution of desorbed methane in the bioassays was determined in treatments with bromoethane sulfonic acid, an inhibitor of microbial methanogenesis. The bioassay compared 16 subbituminous coal samples collected from beds in Texas (TX), Wyoming (WY), and Alaska (AK), and two bituminous coal samples from Pennsylvania (PA). New biogenic methane was observed in several samples of subbituminous coal with the microbial consortium added, but endemic activity was less commonly observed. The highest methane generation [80????mol methane/g coal (56??scf/ton or 1.75??cm3/g)] was from a south TX coal sample that was collected from a non-gas-producing well. Subbituminous coals from the Powder River Basin, WY and North Slope Borough, AK contained more sorbed (original) methane than the TX coal sample and generated 0-23????mol/g (up to 16??scf/ton or 0.5??cm3/g) new biogenic methane in the bioassay. Standard indicators of thermal maturity such as burial depth, nitrogen content, and calorific value did not explain differences in biogenic methane among subbituminous coal samples. No original methane was observed in two bituminous samples from PA, nor was any new methane generated in bioassays of these samples. The bioassay offers a new tool for assessing the potential of coal for biogenic methane generation, and provides a platform for studying the

  13. Genotoxicity of soil from farmland irrigated with wastewater using three plant bioassays.

    PubMed

    Cabrera, G L; Rodriguez, D M

    1999-05-19

    Three well known plant bioassays, the Allium root chromosome aberration (AL-RAA) assay, the Tradescantia micronucleus (Trad-MCN) assay, and the Tradescantia stamen hair (Trad-SHM) mutation assay were validated in 1991 by the International Programme on Chemical Safety (IPCS) under the auspices of the World Health Organization, and the United Nations Environment Programme (UNEP). These plant bioassays have proven to be efficient tests for chemical screening and especially for in situ monitoring for genotoxicity of environmental pollutants. As a result of this validation study, standard protocols of these three plant bioassays were used by some of the 11 participating countries in the IPCS to carry on genotoxicity tests on air, water and soil as a follow up activity. In the city of Queretaro, Mexico, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the farm crops, polluting the soil. Potentially the pollutants could reach the food chain. For the above reason, soil irrigated with wastewater was sampled and monitored for the presence of genotoxic agents using the above three bioassays. Extracts from soil samples were made using distilled water and organic solvents by shaking the sample for about 12 h under a relatively low temperature (15-20 degrees C). Plant cuttings of Tradescantia or the roots of Allium were treated by submerging them in the extracts. Three replicates of each sample were analyzed in each of the three bioassays. Extracts using DMSO, ethanol and distilled water tested positive in the three bioassays and there were no differences for the genotoxicity of the extracts with the different solvents. PMID:10350600

  14. False-Positive Serum Botulism Bioassay in Miller-Fisher Syndrome.

    PubMed

    Zeylikman, Yuriy; Shah, Vishal; Shah, Umang; Mirsen, Thomas R; Campellone, Joseph V

    2015-09-01

    We describe a patient with acute progressive weakness and areflexia. Both botulism and Miller-Fisher variant of Guillain-Barré syndrome were initial diagnostic considerations, and she was treated with intravenous immunoglobulin and botulinum antitoxin. A mouse bioassay was positive for botulinum toxin A, although her clinical course, electrodiagnostic studies, and cerebrospinal fluid findings supported Miller-Fisher syndrome. This patient's atypical features offer points of discussion regarding the evaluation of patients with acute neuromuscular weakness and emphasize the limitations of the botulism bioassay. PMID:26301377

  15. A field bioassay to evaluate potential spatial repellents against natural mosquito populations.

    PubMed

    Chauhan, K R; Aldrich, J R; McCardle, P W; White, G B; Webb, R E

    2012-12-01

    A field bioassay evaluating candidate chemicals as aerial repellents was developed and evaluated against natural mosquito populations in Beltsville, MD. The bioassay consisted of an attractive source surrounded by a grid of 16 septa containing a volatile candidate aerial repellent, compared with an attractive source without such a grid. The attractive source was a Centers for Disease Control and Prevention light trap supplemented with carbon dioxide. Significant sources of variation included weather, position, and the differential response of mosquito species. Despite these sources of variation, significant repellent responses were obtained for catnip oil, E,Z-dihydronepetalactone, and DEET. PMID:23393752

  16. A Brine Shrimp Bioassay for Measuring Toxicity and Remediation of Chemicals

    NASA Astrophysics Data System (ADS)

    Lieberman, Marya

    1999-12-01

    A bioassay using Artemia franciscana (brine shrimp) was adapted to measure the toxicity of household chemicals. One project is described in which students collect dose-response curves for seven commercial flea-killing products. Next, groups of students researched the insecticidal ingredients of the flea products. On the basis of the structures of the active ingredients, they chose remediation methods to make the flea product less toxic to brine shrimp; procedures included copper-catalyzed hydrolysis, adsorption onto activated charcoal, bleach treatment, and photodegradation. No special equipment or supplies are necessary for the bioassay other than the brine shrimp eggs, which can be obtained at any aquarium store.

  17. A versatile electrowetting-based digital microfluidic platform for quantitative homogeneous and heterogeneous bio-assays

    NASA Astrophysics Data System (ADS)

    Vergauwe, Nicolas; Witters, Daan; Ceyssens, Frederik; Vermeir, Steven; Verbruggen, Bert; Puers, Robert; Lammertyn, Jeroen

    2011-05-01

    Electrowetting-on-dielectric (EWOD) lab-on-a-chip systems have already proven their potential within a broad range of bio-assays. Nevertheless, research on the analytical performance of those systems is limited, yet crucial for a further breakthrough in the diagnostic field. Therefore, this paper presents the intrinsic possibilities of an EWOD lab-on-a-chip as a versatile platform for homogeneous and heterogeneous bio-assays with high analytical performance. Both droplet dispensing and splitting cause variations in droplet size, thereby directly influencing the assay's performance. The extent to which they influence the performance is assessed by a theoretical sensitivity analysis, which allows the definition of a basic framework for the reduction of droplet size variability. Taking advantage of the optimized droplet manipulations, both homogeneous and heterogeneous bio-assays are implemented in the EWOD lab-on-a-chip to demonstrate the analytical capabilities and versatility of the device. A fully on-chip enzymatic assay is realized with high analytical performance. It demonstrates the promising capabilities of an EWOD lab-on-a-chip in food-related and medical applications, such as nutritional and blood analyses. Further, a magnetic bio-assay for IgE detection using superparamagnetic nanoparticles is presented whereby the nanoparticles are used as solid carriers during the bio-assay. Crucial elements are the precise manipulation of the superparamagnetic nanoparticles with respect to dispensing and separation. Although the principle of using nano-carriers is demonstrated for protein detection, it can be easily extended to a broader range of bio-related applications like DNA sensing. In heterogeneous bio-assays the chip surface is actively involved during the execution of the bio-assay. Through immobilization of specific biological compounds like DNA, proteins and cells a reactive chip surface is realized, which enhances the bio-assay performance. To demonstrate

  18. Review of Bioassays for Monitoring Fate and Transport ofEstrogenic Endocrine Disrupting Compounds in Water

    SciTech Connect

    CGCampbell@lbl.gov

    2004-01-30

    Endocrine disrupting compounds (EDCs) are recognizedcontaminants threatening water quality. Despite efforts in sourceidentification, few strategies exist for characterization or treatment ofthis environmental pollution. Given that there are numerous EDCs that cannegatively affect humans and wildlife, general screening techniques likebioassays and biosensors provide an essential rapid and intensiveanalysis capacity. Commonly applied bioassays include the ELISA and YESassays, but promising technologies include ER-CALUXa, ELRA, Endotecta,RIANA, and IR-bioamplification. Two biosensors, Endotecta and RIANA, arefield portable using non-cellular biological detection strategies.Environmental management of EDCs in water requires integration ofbiosensors and bioassays for monitoring and assessment.

  19. Highlighting relatedness promotes prosocial motives and behavior.

    PubMed

    Pavey, Louisa; Greitemeyer, Tobias; Sparks, Paul

    2011-07-01

    According to self-determination theory, people have three basic psychological needs: relatedness, competence, and autonomy. Of these, the authors reasoned that relatedness need satisfaction is particularly important for promoting prosocial behavior because of the increased sense of connectedness to others that this engenders. In Experiment 1, the authors manipulated relatedness, autonomy, competence, or gave participants a neutral task, and found that highlighting relatedness led to higher interest in volunteering and intentions to volunteer relative to the other conditions. Experiment 2 found that writing about relatedness experiences promoted feelings of connectedness to others, which in turn predicted greater prosocial intentions. Experiment 3 found that relatedness manipulation participants donated significantly more money to charity than did participants given a neutral task. The results suggest that highlighting relatedness increases engagement in prosocial activities and are discussed in relation to the conflict and compatibility between individual and social outcomes. PMID:21521720

  20. 1999 Guidance, Navigation, and Control Highlights

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.

    1999-01-01

    This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA Centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

  1. 2000 Guidance, Navigation, and Control Highlights

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.

    2000-01-01

    This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

  2. Science Highlights from the Cassini magnetometer instrument

    NASA Astrophysics Data System (ADS)

    Dougherty, Michele

    2014-05-01

    The Cassini dual technique magnetometer instrument has been taking data in the Saturn system for the last 10 years. Science highlights encompass topics including the magnetosphere and its aurora, the internal dynamo magnetic field of Saturn, the icy satellites and Enceladus in particular, as well as the large moon Titan. The science discoveries will be described as well as important science observations yet to be made in the remaining 4 years of the mission.

  3. Recent Highlights from the ISOLDE Facility

    NASA Astrophysics Data System (ADS)

    Johnston, K.

    2015-11-01

    The ISOLDE facility is CERN's longest running experiment. In its 45 years of operation it has become the world's most comprehensive radioactive-isotope factory. Now capable of delivering more than 1000 isotopes from 70 chemical elements, ISOLDE supports a wide and diverse physics programme. This short article summarizes some of the recent highlights from this programme in the areas of nuclear physics, medicine and biology.

  4. STS-111 Flight Day 10 Highlights Replay

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The most important highlight of flight day 10 of STS-111 was the undocking of the Leonardo Multi Purpose Logistical Module (MPLM) from the Unity module of the International Space Station (ISS). The undocking is shown, as is Leonardo resting in Endeavour's payload bay. The video also includes an interview, and footage of the West Africa and the Atlantic Ocean, Gibraltar and the Mediterranean Sea, Italy, Mexico and the Pacific Ocean, Hispanola, an unknown land mass, and unknown mountains.

  5. Laboratory bioassay for assessing the effects of sludge supernatant on plant growth and vesicular-arbuscular mycorrhiza formation

    SciTech Connect

    Bohn, K.S.; Liberta, A.E.

    1982-12-01

    A laboratory bioassay is described for assessing the effects of sludge supernatant on juvenile corn growth and the ability of vesicular-arbuscular (VA) mycorrhizal fungi, indigenous to coal spoil, to form mycorrhizae. The bioassay demonstrated that application rates can be identified that have the potential to promote increased plant dry weight without suppressing the formation of VA mycorrhizae in a plant's root system.

  6. INITIATION/PROMOTION BIOASSAY IN RAT LIVER: USE OF GAMMA GLUTAMYLTRANSPEPTIDASE-POSITIVE FOCI TO INDICATE CARCINOGENIC ACTIVITY

    EPA Science Inventory

    Gamma Glutamyltranspeptidase (GGTase)-positive foci have been used to indicate activity in an initiation/promotion bioassay in rat liver. This rat liver foci bioassay has been proposed for inclusion in tier 2 of a three tier decision tree approach to carcinogenesis testing where ...

  7. Minimization of Between-well Sample Variance of Antifungal Activity Measurements Using a High-Throughput Screening Microplate Bioassay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of microplate bioassays, or broth microdilution assays, to measure the activity of biological and synthetic compounds against fungal pathogens has increased in recent years; this technique has been identified as the most promising in vitro bioassay for quantifying antifungal activity. Quant...

  8. Evaluating macroinvertebrate population and community level effects in outdoor microcosms: Use of in situ bioassays and multivariate analysis

    SciTech Connect

    Shaw, J.L.; Manning, J.P.

    1996-05-01

    Evaluating toxicant effects on aquatic communities is difficult due to the ecological complexity at higher levels of organization. Two methods were assessed to improve the understanding of effects on macroinvertebrate communities in aquatic model ecosystems. First, in situ bioassay population effects were used to interpret effects at a higher organization level. Second, canonical discriminant analysis was used to investigate effects on community structure. In situ bioassays were conducted on six occasions in 17-m{sup 3} microcosms treated with copper sulfate. Macroinvertebrates occurring naturally in the microcosms were monitored. Epibenthic in situ bioassays were conducted using Caenis sp. (Ephemeroptera) and Hyalella azteca (Amphipoda) and a water column bioassay was conducted using Notonectidae (Hemiptera). Survival and growth were assessed after 3 d. Effects of copper on both notonectidae and Caenis were observed following application. However, the final Caenis epibenthic bioassays indicated that potential for recovery and survival was {ge}95%. Potential for recovery was less distinct in the water column bioassays. Copper effects also occurred on epibenthic macroinvertebrate populations and communities. Only four taxa, including Caenis, distinguished community differences among copper treatments soon after application. Later, communities showed similarities to the pretreatment bioassay. However, actual recovery was less apparent than the potential for recovery indicated by the bioassays, and community differences due to Caenis persisted.

  9. COMPARISON OF BIOASSAY AND ENZYME-LINKED IMMUNOSORBENT ASSAY FOR QUANTIFICATION OF 'SPODOPTERA FRUGIPERDA' NUCLEAR POLYHEDROSIS VIRUS IN SOIL

    EPA Science Inventory

    Standard curves with known amounts of Spodoptera frugiperda nuclear polyhedrosis virus (NPV) in soil were established with a bioassay and with an enzyme-linked immunosorbent assay (ELISA). The bioassay detected as few as 4 x 10 to the 4th power polyhedral inclusion bodies (PIB)/g...

  10. STS-109 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-05-01

    This video, Part 3 of 4, shows the activities of the STS-109 crew (Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, James Newman, Richard Linnehan, Michael Massimino, Mission Specialists) during flight days 6 and 7. The activities from other flight days can be seen on 'STS-109 Mission Highlights Resource Tape' Part 1 of 4 (internal ID 2002139471), 'STS-109 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002137664), and 'STS-109 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002137577). Flight day 6 features a very complicated EVA (extravehicular activity) to service the HST (Hubble Space Telescope). Astronauts Grunsfeld and Linnehan replace the HST's power control unit, disconnecting and reconnecting 36 tiny connectors. The procedure includes the HST's first ever power down. The cleanup of spilled water from the coollant system in Grunsfeld's suit is shown. The pistol grip tool, and two other space tools are also shown. On flight day 7, Newman and Massimino conduct an EVA. They replace the HST's FOC (Faint Object Camera) with the ACS (Advanced Camera for Surveys). The video ends with crew members playing in the shuttle's cabin with a model of the HST.

  11. Unusual non-fluorescent broad spectrum siderophore activity (SID EGYII) by Pseudomonas aeruginosa strain EGYII DSM 101801 and a new insight towards simple siderophore bioassay.

    PubMed

    Embaby, Amira M; Heshmat, Yasmin; Hussein, Ahmed

    2016-03-01

    Present study highlights an unusual non-fluorescent hydroxamate broad spectrum siderophore (SID EGYII) activity from Pseudomonas aeruginosa strain EGYII DSM 101801, a soil bacterial isolate, along with simple low cost effective siderophore bioassay. Detection of SID EGYII activity qualitatively was proved by masking this activity against Erwinia amylovora strain EGY1 DSM 101800, an indicator strain, in well-cut diffusion assay containing 100 µM FeCl3. SID EGYII activity was expressed quantitatively as arbitrary units [Siderophore arbitrary units (SAU)] 380 SAU/mL against E. amylovora strain EGY1 DSM 101800. Maximal SID EGYII activity was achieved upon growing P. aeruginosa strain EGYII DSM 101801 in PYB broth at 180 rpm for 24 h. SID EGYII displayed a broad spectrum antimicrobial activity against some human pathogens (i.e., Gram-positive bacteria, Gram-negative bacteria and yeasts) and a fireblight plant pathogen. Interestingly, transformants of Escherichia coli JM109 (DE3)pSID/EGYII harboring P. aeruginosa strain EGYII DSM 101801 plasmid demonstrated a perceivable antimicrobial activity against E. amylovora strain EGY1 DSM 101800. The broad spectrum antimicrobial activity of the unusual non-fluorescent SID EGYII would underpin its high potential in targeting bacterial pathogens posing probable threats to human health and agricultural economy. The present simple low cost effective bioassay is a new insight towards an alternative to the expensive cumbersome siderophore Chrome Azurol S assay. PMID:27015845

  12. Summary of the EPA (Environmental Protection Agency) workshop on carcinogenesis bioassay via the dermal route. Final technical report

    SciTech Connect

    Not Available

    1987-04-29

    Traditionally, the oral route has been the most common route of administration in bioassays which tested the potential carcinogenicity of chemicals. Regulatory agencies, however, prefer to have test chemicals applied by the same route as expected human exposure, whenever possible. Since human exposure to industrial chemicals is frequently via the dermal route, this has become a route of choice for animal testing of certain chemicals. However, protocol design for dermal bioassays presents many unique problems which must be addressed before guidelines for bioassays by the dermal route can be formulated. Furthermore, it may be feasible to develop a limited dermal protocol to screen certain classes of chemicals such as acrylates/methacrylates. Recognizing the need for this workshop, it was designed in two distinct parts; to address the problems inherent in the development of a generic protocol for dermal bioassays and, a specific limited dermal bioassay protocol for acrylates/methacrylates.

  13. A yeast bioassay for direct measurement of thyroid hormone disrupting effects in water without sample extraction, concentration, or sterilization.

    PubMed

    Li, Jian; Ren, Shujuan; Han, Shaolun; Li, Na

    2014-04-01

    The present study introduces an improved yeast bioassay for rapid yet sensitive evaluation of thyroid hormone disruption at the level of thyroid receptor (TR) in environmental water samples. This assay does not require water sample preparation and thus requires very little hands-on time. Based on different β-galactosidase substrates, two modified bioassays, a colorimetric bioassay and a chemiluminescent bioassay, were developed. The compounds tested included the known thyroid hormone 3,3',5-triiodo-l-thyronine (T3), the specific TR antagonist amiodarone hydrochloride (AH) and phthalate esters (PAEs), which potentially disrupt thyroid hormone signaling. The EC50 values for T3 were similar to those previously obtained using a 96-well plate bioassay. TR antagonism by AH was studied in the presence of 2.5 × 10(-7)M T3, and the concentration producing 20% of the maximum effect (RIC20) for AH was 3.1 × 10(-7)M and 7.8 × 10(-9)M for the colorimetric bioassay and chemiluminescent bioassay, respectively. None of the tested PAEs induced β-galactosidase expression, but diethylhexyl phthalate, benzyl butyl phthalate and dibutyl phthalate demonstrated TR antagonism. Furthermore, water samples collected from Guanting reservoir in Beijing were evaluated. Although TR agonism was not observed, antagonism was detected in all water samples and is expressed as AH equivalents. The toxicology equivalent quantity values obtained by the chemiluminescent bioassay ranged from 21.2 ± 1.6 to 313.9 ± 28.8 μg L(-1) AH, and similar values were obtained for the colorimetric bioassay. The present study shows that the modified yeast bioassay can be used as a valuable tool for quantification of thyroid hormone disrupting effects in environmental water samples. PMID:24355165

  14. OBSERVATIONS ON THE 10-DAY CHIRONOMUS TENTANS SURVIVAL AND GROWTH BIOASSAY IN EVALUATING GREAT LAKES SEDIMENTS

    EPA Science Inventory

    A 10-day bioassay with larval chironomids (Chironomus tentans) was used to evaluate sediment samples from harbors at Michigan City, IN, St. Joseph, MI, Grand Haven, MI and Toledo, OH for toxicity, based on the endpoints of survival, dry weight, and growth. Larval responses in se...

  15. Using a Macroalgal δ15N Bioassay to Detect Cruise Ship Waste Water Effluent Inputs

    EPA Science Inventory

    Nitrogen stable isotopes are a powerful tool for tracking sources of N to marine ecosystems. I used green macroalgae as a bioassay organism to evaluate if the δ15N signature of cruise ship waste water effluent (CSWWE) could be detected in Skagway Harbor, AK. Opportunistic green...

  16. APPLICATION OF SHORT-TERM BIOASSAYS IN THE FRACTIONATION AND ANALYSIS OF COMPLEX ENVIRONMENTAL MIXTURES

    EPA Science Inventory

    The report is the proceedings of a symposium convened at Williamsburg, Virginia February 21-23, 1978. The volume consists of 24 formal presentations that amplify the three major topics discussed during the symposium: an overview of short-term bioassay systems; current methodology...

  17. Relationships of maternal and fetal weight changes in developmental toxicology bioassays

    EPA Science Inventory

    Standard developmental toxicology bioassays are designed to identify agents with the potential to induce adverse effects in the embryo/fetus. Guidelines require the inclusion of a dose level(s) that induces “overt maternal toxicity”. The common occurrence of dose levels at which ...

  18. Maternal and fetal toxicity in developmental toxicology bioassays: Weight changes and their biological significance

    EPA Science Inventory

    Standard developmental toxicology bioassays are designed to identify agents with the potential to induce adverse effects in the embryo/fetus. Guidelines call for the inclusion of a dose level(s) that induces “overt maternal toxicity.” The possibility that general maternal toxicit...

  19. The Intersection of CMOS Microsystems and Upconversion Nanoparticles for Luminescence Bioimaging and Bioassays

    PubMed Central

    Wei, Liping.; Doughan, Samer.; Han, Yi.; DaCosta, Matthew V.; Krull, Ulrich J.; Ho, Derek.

    2014-01-01

    Organic fluorophores and quantum dots are ubiquitous as contrast agents for bio-imaging and as labels in bioassays to enable the detection of biological targets and processes. Upconversion nanoparticles (UCNPs) offer a different set of opportunities as labels in bioassays and for bioimaging. UCNPs are excited at near-infrared (NIR) wavelengths where biological molecules are optically transparent, and their luminesce in the visible and ultraviolet (UV) wavelength range is suitable for detection using complementary metal-oxide-semiconductor (CMOS) technology. These nanoparticles provide multiple sharp emission bands, long lifetimes, tunable emission, high photostability, and low cytotoxicity, which render them particularly useful for bio-imaging applications and multiplexed bioassays. This paper surveys several key concepts surrounding upconversion nanoparticles and the systems that detect and process the corresponding luminescence signals. The principle of photon upconversion, tuning of emission wavelengths, UCNP bioassays, and UCNP time-resolved techniques are described. Electronic readout systems for signal detection and processing suitable for UCNP luminescence using CMOS technology are discussed. This includes recent progress in miniaturized detectors, integrated spectral sensing, and high-precision time-domain circuits. Emphasis is placed on the physical attributes of UCNPs that map strongly to the technical features that CMOS devices excel in delivering, exploring the interoperability between the two technologies. PMID:25211198

  20. Complete Genome Sequence of Cyanobium sp. NIES-981, a Marine Strain Potentially Useful for Ecotoxicological Bioassays

    PubMed Central

    Shimura, Yohei; Suzuki, Shigekatsu; Yamagishi, Takahiro; Tatarazako, Norihisa; Kawachi, Masanobu

    2016-01-01

    Cyanobium sp. NIES-981 is a marine cyanobacterium isolated from tidal flat sands in Okinawa, Japan. Here, we report the complete 3.0-Mbp genome sequence of NIES-981, which is composed of a single chromosome, and its annotation. This sequence information may provide a basis for developing an ecotoxicological bioassay using this strain. PMID:27469961

  1. Utilization of a duckweed bioassay to evaluate leaching of heavy metals in smelter contaminated soils

    SciTech Connect

    Youngman, A.L.; Lydy, M.J.; Williams, T.L.

    1998-12-31

    The purpose of this study was to determine whether a duckweed bioassay could be used to evaluate the downward migration of heavy metals in smelter soils. The duckweed bioassay was initially used to evaluate elutriates prepared from samples of smelter soils. These initial tests verified that the elutriates would elicit toxic responses. Elutriate testing was followed with an evaluation of leachate from untreated soil cores or soil cores that had been amended with organic matter either unplanted or planted to a grass-forb seed mixture. There was an inverse linear relationship between heavy-metal concentrations in leachate and NOEC and IC{sub 50} values expressed as percentages among all soil cores. Based on these preliminary duckweed bioassays, there were no differences between soil types or organic amended or non-amended soil, but leachate from vegetated soil cores were less toxic than were leachates from non-vegetated soil cores. Overall, the duckweed bioassays were useful in detecting heavy metal availability in elutriate and leachate samples from smelter soils.

  2. CADMIUM SPECIATION IN AQUATIC-LIFE FLOW-THROUGH BIOASSAY DILUTERS

    EPA Science Inventory

    A framework of cadmium speciation studies is described for flow-through mini-diluter bioassay systems which employs Lake Superior water containing added concentrations of calcium carbonate, Aldrich humic acid and/or less than 2 microns suspended Lake Superior red clay. Aspects of...

  3. Development of bioassay techniques with extracts from semi-permeable membrane devices (SPMDs)

    SciTech Connect

    Metcalfe, T.L.; White, P.; Mackay, D.; Metcalfe, C.

    1995-12-31

    Semi-permeable membrane devices (SPMDs), consisting of polyethylene bags filled with triolein, have been used to monitor for lipophilic organic contaminants in water. Although extracts from SPMDs have most often been analyzed for concentrations of organic contaminants, there is also the potential to monitor the toxicity of these extracts using in vitro and in vivo bioassays. SPMDs were deployed for four weeks at several sites along a corridor extending from Peche Island in the Detroit River to Pelee Island in western Lake Erie to monitor the distribution of toxic organic contaminants in the water. Analysis of the extracts from the SPMDs for concentrations of PCBs and other organochlorine compounds, and polynuclear aromatic hydrocarbons (PAHs) indicated that the regions in the Detroit River within the Trenton Channel and near Zug Island were the most highly contaminated. Bioassays conducted with extracts from the SPMDs included the in vitro SOS Chromotest for genotoxic activity, an acute lethality test with Daphnia magna, and a fish embryotoxicity test with embryos of Japanese medaka (Oryzias latipes). These bioassay data generally indicated that the toxicity and concentrations of organic contaminants in the SPMD extracts were correlated. This study indicates that there is potential to use short-term bioassays of extracts from SPMDs to monitor for in situ contamination in the aquatic environment.

  4. Development of an in vitro rainbow trout cell bioassay for PCBs and dioxins

    SciTech Connect

    Richter, C.A.; Leykam, V.; Giesy, J.P.; Denison, M.S.

    1994-12-31

    The toxicity of PCBs, dioxins, and other halogenated aromatic hydrocarbons (HAHS) is difficult to predict from chemical analysis alone, since these chemicals occur in complex mixtures and participate in interactions. Since HAH toxicity is correlated with affinity for the aromatic hydrocarbon receptor (AhR), bioassays which measure induction of genes controlled by the AhR can predict toxicity. The authors have developed a bioassay relevant to fish derived from the RTH-149 rainbow trout hepatoma cell line. The parent cell line has been stably transfected with the plasmid pGudLucl.l. This plasmid contains the firefly luciferase reporter gene under the control of mouse DRES. The reporter gene is controlled only by the AhR, and its induction can be detected at low levels. The bioassay will be fully characterized and calibrated to the responses of whole fish exposed to HAHS. The bioassay exhibits detectable induction at 100 fM TCDD after a three day exposure. Induction increases in a linear relationship with time up to four days of exposure. Luciferase activity was induced to 1 7.5 times background activity after four days of exposure to 1 nM TCDD.

  5. An in vitro rainbow trout cell bioassay for aryl hydrocarbon receptor-mediated toxins

    SciTech Connect

    Richter, C.A.; Tieber, V.L.; Giesy, J.P.; Denison, M.S.

    1997-03-01

    Halogenated aromatic hydrocarbons (HAHs) and other chemicals that act as aryl hydrocarbon (Ah) receptor (AhR) agonists cause a variety of toxicity effects. In sac fry of many fish species, these effects include blue-sac disease and mortality. Because HAHs occur in complex mixtures, their toxicity in the environment is difficult to predict. A bioassay useful in predicting AhR-mediated toxicity to fish was developed using the RTH-149 rainbow trout hepatoma cell line. Stable transfection of this cell line with the pGudLuc 1.1 plasmid, which contains a firefly luciferase reporter gene under the transcriptional regulation of dioxin responsive enhancers, has produced a recombinant cell line designated Remodulated Lightning Trout (RLT 2.0). The RLT 2.0 bioassay method detection limit for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is 4 pM. The responses of the RLT 2.0 bioassay to TCDD and several HAH congeners closely matched the responses observed in vivo in fish. The RLT 2.0 bioassay can provide an integrative measure of the total AhR-mediated toxic activity of complex mixtures to fish. The assay will be useful in screening environmental extracts, guiding chemical analysis, and interpreting the AhR-mediated mechanism of toxicity.

  6. The use of bioassay to determine the effects of cooking on the toxicity of fumonisins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumonisins are mycotoxin contaminants of maize. Fumonisin B1 (FB1), the most common and toxic fumonisin, causes species-specific diseases in animals, is carcinogenic to rodents, and induces neural tube defects (NTD) in LM/Bc and CD1 mouse bioassays. The human health implications associated with FB1...

  7. Determination of Biochemical Oxygen Demand of Area Waters: A Bioassay Procedure for Environmental Monitoring

    ERIC Educational Resources Information Center

    Riehl, Matthew

    2012-01-01

    A graphical method for determining the 5-day biochemical oxygen demand (BOD5) for a body of water is described. In this bioassay, students collect a sample of water from a designated site, transport it to the laboratory, and evaluate the amount of oxygen consumed by naturally occurring bacteria during a 5-day incubation period. An accuracy check,…

  8. Study of the interactions between copper, cadmium, and ferbam using the protozoan Colpidium campylum bioassay.

    PubMed

    Sekkat, N; Le Dû, A; Jouany, J M; Guerbet, M

    1992-12-01

    The toxicity of a copper-cadmium-ferbam mixture has been studied using the protozoan Colpidium campylum bioassay. The assays were designed according to the factorial experiments method, associated with multiple regression analysis. The results show that, at the concentrations tested, a synergy occurs between cadmium and ferbam, whereas the copper is only oligodynamic. PMID:1282874

  9. Experience with NQA-1 quality assurance standards applied to in vitro bioassay

    SciTech Connect

    Bihl, D.E.; MacLellan, J.A.

    1991-10-01

    On June 1, 1990, the large (about 4000 samples per year) excreta bioassay program at the Hanford Site ceased abruptly when the contract with the bioassay laboratory was terminated. An intense, high-priority effort was begun to replace the services on an interim basis until a new contract could be procured. Despite the urgency to get the excreta bioassay program going again, the Hanford Internal Dosimetry Program was constrained to use only labs that could meet stringent quality assurance (QA) requirements, even during the interim period. The QA requirements were based on NQA-1 with selected additions from the Environmental Protection Agency's QAMS 005/80 (EPA 1983) and the American Society for Testing and Materials' C 1009-83 (ASTM 1984). This constraint was driven both by legal reasons and by the Hanford Site contractors and workers not wanting the quality of the data to be sacrificed. Finding labs that could (1) handle the large throughput, (2) meet the technical requirements, and (3) pass the QA audit proved more difficult than first anticipated. This presentation focuses on the QA requirements that the labs had to meet and how those very broad requirements were applied specifically to excreta bioassay. 5 refs.

  10. Complete Genome Sequence of Cyanobium sp. NIES-981, a Marine Strain Potentially Useful for Ecotoxicological Bioassays.

    PubMed

    Yamaguchi, Haruyo; Shimura, Yohei; Suzuki, Shigekatsu; Yamagishi, Takahiro; Tatarazako, Norihisa; Kawachi, Masanobu

    2016-01-01

    Cyanobium sp. NIES-981 is a marine cyanobacterium isolated from tidal flat sands in Okinawa, Japan. Here, we report the complete 3.0-Mbp genome sequence of NIES-981, which is composed of a single chromosome, and its annotation. This sequence information may provide a basis for developing an ecotoxicological bioassay using this strain. PMID:27469961

  11. Is there a role for estrogen activity assays? Recombinant cell bioassay for estrogen: Development and applications.

    PubMed

    Klein, Karen Oerter

    2015-07-01

    There are many questions which cannot be answered without a very sensitive estradiol assay. A recombinant cell bioassay (RCBA) for estradiol was developed in 1994. The sensitivity of the bioassay is 0.02-0.2 pg/ml (0.07-0.7 pmol/L), more than 20 times more sensitive than commercial RIAs and 10 times more sensitive than newer mass spectrometry assays. The RCBA for estradiol opened the door to study low levels of estradiol equivalents (EE) across the physiological spectrum of life from prepubertal children through menopause and across the spectrum from normal physiology, in boys as well as girls, to pathology, including: premature thelarche; estradiol suppression in children treated with GnRH analogues for precocious puberty; aromatase inhibition in boys with growth hormone deficiency; the differences between oral and transdermal routes of estrogen administration in girls with Turner's syndrome; women with breast cancer treated with aromatase inhibitors; and women with urogenital atrophy treated with low dose vaginal estrogen. A bioassay also allows study of endocrine disruptors, like phytoestrogens and other environmental compounds, which are relevant to public health and alternative medicine options. This paper reviews the assay and the last 20 years of applications. A bioassay for estrogen has a role because measuring biological effect is theoretically useful, increasing the understanding of physiology in addition to biochemical levels, giving different information than other assays, and opening the door to measure very low levels of estrogen activity in both humans and the environment. PMID:25159103

  12. A cellulose-based bioassay for the colorimetric detection of pathogen DNA.

    PubMed

    Saikrishnan, Deepika; Goyal, Madhu; Rossiter, Sharon; Kukol, Andreas

    2014-12-01

    Cellulose-paper-based colorimetric bioassays may be used at the point of sampling without sophisticated equipment. This study reports the development of a colorimetric bioassay based on cellulose that can detect pathogen DNA. The detection was based on covalently attached single-stranded DNA probes and visual analysis. A cellulose surface functionalized with tosyl groups was prepared by the N,N-dimethylacetamide-lithium chloride method. Tosylation of cellulose was confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. Sulfhydryl-modified oligonucleotide probes complementary to a segment of the DNA sequence IS6110 of Mycobacterium tuberculosis were covalently immobilized on the tosylated cellulose. On hybridization of biotin-labelled DNA oligonucleotides with these probes, a colorimetric signal was obtained with streptavidin-conjugated horseradish peroxidase catalysing the oxidation of tetramethylbenzamidine by H2O2. The colour intensity was significantly reduced when the bioassay was subjected to DNA oligonucleotide of randomized base composition. Initial experiments have shown a sensitivity of 0.1 μM. A high probe immobilization efficiency (more than 90 %) was observed with a detection limit of 0.1 μM, corresponding to an absolute amount of 10 pmol. The detection of M. tuberculosis DNA was demonstrated using this technique coupled with PCR for biotinylation of the DNA. This work shows the potential use of tosylated cellulose as the basis for point-of-sampling bioassays. PMID:25354892

  13. Bioassay and Attributes of a Growth Factor Associated with Crown Gall Tumors 1

    PubMed Central

    Lippincott, Barbara B.; Lippincott, James A.

    1970-01-01

    An improved bioassay is described for a factor that promotes tumor growth which was first obtained from extracts of pinto bean leaves with crown gall tumors. Sixteen primary pinto bean leaves per sample are inoculated with sufficient Agrobacterium tumefaciens to initiate about 5 to 10 tumors per leaf and treated with tumor growth factor at day 3 after inoculation. The diameters of 30 to 48 round tumors (no more than 3 randomly selected per leaf) are measured per test sample at day 6. Mean tumor diameter increased linearly with the logarithm of the concentration of tumor growth factor applied. The tumor growth factor was separated by column chromatography from an ultraviolet light-absorbing compound previously reported to be associated with fractions having maximal tumor growth factor activity. Partly purified tumor growth factor showed no activity in a cytokinin bioassay or an auxin bioassay, and negligible activity in gibberellin bioassays. Representatives of these three classes of growth factors did not promote tumor growth. Extracts from crown gall tumors on primary pinto bean leaves, primary castor bean leaves, Bryophyllum leaves, carrot root slices, and tobacco stems showed tumor growth factor activity, whereas extracts from healthy control tissues did not. Extracts from actively growing parts of healthy pinto beans, Bryophyllum, and tobacco, however, showed tumor growth factor activity. Tumor growth factor is proposed to be a normal plant growth factor associated with rapidly growing tissues. Its synthesis may be activated in nongrowing tissues by infection with Agrobacterium sp. PMID:16657534

  14. SHORT-TERM CARCINOGENESIS AND MUTAGENESIS BIOASSAYS OF UNREGULATED AUTOMOTIVE EMISSIONS

    EPA Science Inventory

    Evaluation of the potential risk of a chemical or environmental emission causing chronic health effects requires data from one or more of the following sources: epidemiologic and clinical studies of human exposure and effects; chronic (long term) bioassays in animals; and short-t...

  15. TECHNIQUE FOR REMOVAL OF DISSOLVED AND DISPERSED HYDROCARBONS FROM BIOASSAY EFFLUENTS

    EPA Science Inventory

    A method for the efficient removal of petroleum-derived hydrocarbons from the oil-contaminated effluent of a continuous flow-through oil bioassay system is described. The concentration of No. 2 fuel oil in the effluent, discharged at rates from 17 to 26 L/min, is reduced from an ...

  16. Evaluation of soil bioassays for use at Washington state hazardous waste sites: A pilot study

    SciTech Connect

    Blakley, N.; Norton, D.; Stinson, M.; Boyer, R.

    1994-12-31

    The Washington State Department of Ecology (Ecology) is developing guidelines to assess soil toxicity at hazardous waste sites being investigated under the Washington Model Toxics Control Act Cleanup Regulation. To evaluate soil toxicity, Ecology selected five bioassay protocols -- Daphnia, Earthworm, Seedling, Fathead Minnow, and Frog Embryo Teratogenesis Assay Xenopus (FETAX) -- for use as screening level assessment tools at six State hazardous waste sites. Sites contained a variety of contaminants including metals, creosote, pesticides, and petroleum products (leaking underground storage tanks). Three locations, representing high, medium, and low levels of contamination, were samples at each site. In general, the high contaminant samples resulted in the highest toxic response in all bioassays. The order of site toxicity, as assessed by overall toxic response, is creosote, petroleum products, metals, and pesticides. Results indicate that human health standards, especially for metals, may not adequately protect some of the species tested. The FETAX bioassay had the greatest overall number of toxic responses and lowest variance. The seedling and Daphnia bioassays had lower and similar overall toxic response results, followed by the earthworm and fathead minnow. Variability was markedly highest for the seedling. The Daphnia and fathead minnow variability were similar to the FETAX level, while the earthworm variability was slightly higher.

  17. An Estuarine Fish Bioassay for Sensitive Biomonitoring of Oil-related Contamination

    EPA Science Inventory

    An embryonic and larval bioassay using the estuarine fish, Fundulus heteroclitus, was modified for the rapid detection of bioavailable compounds that act through the aryl hydrocarbon receptor (AhR). The early development of fishes is particularly sensitive to AhR agonists, such ...

  18. SUPERNUMERARY RIBS IN DEVELOPMENTAL TOXICITY BIOASSAYS AND IN HUMAN POPULATIONS: INCIDENCE AND BIOLOGICAL SIGNIFICANCE

    EPA Science Inventory

    Abstract
    Supernumerary or accessory ribs (SNR), either lumbar (LSNR) or cervical (CSNR) are a common finding in standard developmental toxicology bioassays. The biological significance of these anomalies within the regulatory arena has been problematic and the subject of some...

  19. Olfactoryresponse of the predatory mite Typhlodromus pyri (Acari: Phytoseiidae) to methyl salicylate in laboratory bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The response of Typhlodromus pyri, a key predator of grapevine rust mite (Calepitrimerus vitis), to MeSA was tested using a Y-tube olfactometer in laboratory bioassays. Six doses ranging from 200 to 0.002 µg of diluted MeSA were tested. Significantly higher proportions of T. pyri preferred MeSA at ...

  20. Determining UV Inactivation of Toxoplasma gondii Oocysts by Using Cell Culture and a Mouse Bioassay

    EPA Science Inventory

    The effect of UV exposure on Toxoplasma gondii oocysts has not been completely defined for use in water disinfection. This study evaluated UV irradiated oocysts by three assays: a SCID mouse bioassay, an in vitro T. gondii oocyst plaque assay (TOP-assay), and a quantitative reve...

  1. Statistical method for determining and comparing limits of detection of bioassays.

    PubMed

    Holstein, Carly A; Griffin, Maryclare; Hong, Jing; Sampson, Paul D

    2015-10-01

    The current bioassay development literature lacks the use of statistically robust methods for calculating the limit of detection of a given assay. Instead, researchers often employ simple methods that provide a rough estimate of the limit of detection, often without a measure of the confidence in the estimate. This scarcity of robust methods is likely due to a realistic preference for simple and accessible methods and to a lack of such methods that have reduced the concepts of limit of detection theory to practice for the specific application of bioassays. Here, we have developed a method for determining limits of detection for bioassays that is statistically robust and reduced to practice in a clear and accessible manner geared at researchers, not statisticians. This method utilizes a four-parameter logistic curve fit to translate signal intensity to analyte concentration, which is a curve that is commonly employed in quantitative bioassays. This method generates a 95% confidence interval of the limit of detection estimate to provide a measure of uncertainty and a means by which to compare the analytical sensitivities of different assays statistically. We have demonstrated this method using real data from the development of a paper-based influenza assay in our laboratory to illustrate the steps and features of the method. Using this method, assay developers can calculate statistically valid limits of detection and compare these values for different assays to determine when a change to the assay design results in a statistically significant improvement in analytical sensitivity. PMID:26376354

  2. A MARINE ALGAL BIOASSAY METHOD: RESULTS WITH PESTICIDES AND INDUSTRIAL WASTES

    EPA Science Inventory

    A simple marine algal bioassay method is described for short- and long-term studies on pesticides and industrial wastes. It can be used for rapid screening of a variety of substances with single-species and multiple-species tests and gives relative toxicities of the pollutants te...

  3. A SIMPLE, RAPID BIOASSAY FOR DETECTING EFFECTS OF POLLUTANTS ON BACTERIA

    EPA Science Inventory

    Since approximately 90% of hazardous wastes reach soil and water for permanent disposal, it is logical that microflora (bacteria) contained in these environments be used to establish initial toxicity levels. Bacteria can be suitable bioassay tools because they are inexpensive to ...

  4. Risk assessment for selected xenobiotics by bioassay methods with higher plants

    NASA Astrophysics Data System (ADS)

    Günther, Petra; Pestemer, Wilfried

    1990-05-01

    Different bioassays with higher plants were approved for use in a bioassay procedure for testing of xenobiotics according to the German Chemicals Act. Selected environmental pollutants (atrazine, cadmium chloride, 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, thiourea), all from a list of reference chemicals, were tested with these methods. Dose-response curves for growth of oats and turnips were evaluated in soil and vermiculite (nonsorptive substrate), and availability to plants was calculated by comparing the EC50 values for one chemical in both substrates. The most active chemical was atrazine, followed by 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, cadmium chloride, and thiourea. The least available compound to plants was pentachlorophenol, tested with turnips ( Brassica rapa var. rapa). The strongest inhibition of germination, demonstrated in an in vitro assay with garden cress ( Lepidium sativum), was found with 2,6-dichlorobenzonitrile, the lowest with atrazine. The effect of an extended exposure of the plants to the chemicals was evaluated in a long-term bioassay with oats ( Avena sativa) in hydroponic culture. Several dose-response curves during the growing period were derived. It was found that the EC50 values for atrazine and thiourea decreased markedly during the first four weeks; thereafter the changes were much smaller. As an overall conclusion, a bioassay procedure is proposed that can be included in the graduated plan recommended by the German Chemicals Act.

  5. Rapid diagnosis of imazapic & imazapyr resistance by using bioassays in Clearfield Production System, Malaysia

    NASA Astrophysics Data System (ADS)

    Bajrai F. S., M.; Ismail B., S.; Mardiana-Jansar, Khairiatul

    2015-09-01

    The resistance of weedy rice biotypes toward OnDuty™WG has been reported in Clearfield® MR 220 CL1 and MR 220 CL2 types of paddy. The purpose of this study was to adopt a rapid method to evaluate the resistance of bioassay species towards imazapic + imazapyr in different stages of plant development (seeds and seedlings). A series of OnDuty™WG concentrations from 0 to 300 g ai ha-1 were studied on the growth of rice cultivar MR263 (a susceptible species) as the bioassay species. The experiments were done in three replications with Complete Randomized Block Design (CRBD). From this study, the concentration of herbicide required to reduce coleoptiles length, root length and fresh weight in seed bioassay by 50% were 0.63, 0.33 and 3.60 g ai ha-1 respectively. Meanwhile, for seedling stage bioassay, the concentration of herbicide required to reduce coleoptiles length, root length and fresh weight by 50% were 0.03, 1.23 and 0.99 g ai ha-1 respectively. It is important to note that all growth parameters were concentration dependent and a total growth inhibition occurred in all parameters at high doses. It was proven that MR263 rice cultivar was not resistance towards imazapic + imazapyr and further experiments on other rice cultivars are recommended so that the most suitable cultivars will be selected in rice cultivation.

  6. Utilizing high throughput bioassays to characterize the bioactivity of complex environmental samples

    EPA Science Inventory

    Bioassays can be employed to evaluate the integrated effects of complex mixtures of both known and unidentified contaminants present in environmental samples. However, such methods have typically focused on one or a few bioactivities despite the fact that the chemicals in a mixtu...

  7. Efficiency of several cultural methods and a chick bioassay to recover dry stressed Campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aims of the study were to evaluate the efficacy of 5 enrichment procedures for recovery of dry-atmospheric-temperature stressed C. jejuni and C. coli and determine the viable status of the non-culturable strains using a chick bioassay. Sterile chick paper pads (PP) and filter papers (FP) were i...

  8. The release of rat intestinal cholecystokinin after oral trypsin inhibitor measured by bio-assay.

    PubMed Central

    Brand, S J; Morgan, R G

    1981-01-01

    The distribution, molecular form and release of cholecystokinin (CCK)-like activity in extracts of rat small intestine was studied with an in vitro gall-bladder bio-assay. In contrast to the reported heterogeneity of CCK-like immunoreactivity in the intestine, only a single molecular form of CCK-like activity was detected using the bio-assay. 2. The CCK-like activity eluted from Sephadex G50 with a Kav of 0.69, after the triacontriapeptide of cholecystokinin (CCK33) and before cholecystokinin octapeptide 2500, may represent the 22 amino acid peptide of CCK (CCK22). The bio-assay peak of CCK-like activity had pancreozymin activity and CCK/gastrin C terminal immunoreactivity. The CCK-like activity weas readily extracted from the small intestine at neutral pH, but subsequent treatment with cold 0.5 M-acetic acid extracted further CCK-like activity of the same molecular form as that recovered under neutral conditions. 3. The bio-assay detected no CCK-like activity, nor was pancreozymin-like activity found in fractions corresponding to CCK33 or CCK8 after Sephadex G50 chromatography of rat intestinal extracts. 4. Oral trypsin inhibitor was a potent stimulus for the release of CCK-like activity from the upper small intestine of the rat. After oral trypsin inhibitor release, CCK-like activity was rapidly resynthesized. PMID:7320918

  9. A bioassay approach for determining the effect of cooking on fumonisin today

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumonisin mycotoxins are found in corn and corn-based foods, but the effect of cooking on fumonisin toxicity has not been studied extensively. Rat feeding studies were used as an in vivo bioassay to compare the toxicity of extrusion cooked and nixtamalized (alkaline cooked) fumonisin-contaminated p...

  10. Parlin, a general microcomputer program for parallel-line analysis of bioassays.

    PubMed

    Jesty, J; Godfrey, H P

    1986-04-01

    Commonly used manual and calculator methods for analysis of clinically important parallel-line bioassays are subject to operator bias and provide neither confidence limits for the results nor any indication of their validity. To remedy this, the authors have written a general program for statistical analysis of these bioassays for the IBM Personal Computer and its compatibles. The program has been used for analysis of bioassays for specific coagulation factors and inflammatory lymphokines and for radioimmunoassays for prostaglandins. The program offers a choice of no transform, logarithmic, or logit transformation of data, which are fitted to parallel lines for standard and unknown. It analyzes the fit for parallelism and linearity with an F test, and calculates the best estimate of the result and its 95% confidence limits. Comparison of results calculated by PARLIN with those previously obtained manually shows excellent correlation (r greater than 0.99). Results obtained using PARLIN are quickly available with current assay technics and provide a complete evaluation of the bioassay at no increase in cost. PMID:3456698

  11. Novel bacterial bioassay for a high-throughput screening of 4-hydroxyphenylpyruvate dioxygenase inhibitors.

    PubMed

    Rocaboy-Faquet, Emilie; Noguer, Thierry; Romdhane, Sana; Bertrand, Cédric; Dayan, Franck Emmanuel; Barthelmebs, Lise

    2014-08-01

    Plant 4-hydroxyphenylpyruvate dioxygenase (HPPD) is the molecular target of a range of synthetic β-triketone herbicides that are currently used commercially. Their mode of action is based on an irreversible inhibition of HPPD. Therefore, this inhibitory capacity was used to develop a whole-cell colorimetric bioassay with a recombinant Escherichia coli expressing a plant HPPD for the herbicide analysis of β-triketones. The principle of the bioassay is based on the ability of the recombinant E. coli clone to produce a soluble melanin-like pigment, from tyrosine catabolism through p-hydroxyphenylpyruvate and homogentisate. The addition of sulcotrione, a HPPD inhibitor, decreased the pigment production. With the aim to optimize the assay, the E. coli recombinant clone was immobilized in sol-gel or agarose matrix in a 96-well microplate format. The limit of detection for mesotrione, tembotrione, sulcotrione, and leptospermone was 0.069, 0.051, 0.038, and 20 μM, respectively, allowing to validate the whole-cell colorimetric bioassay as a simple and cost-effective alternative tool for laboratory use. The bioassay results from sulcotrione-spiked soil samples were confirmed with high-performance liquid chromatography. PMID:24816780

  12. A RAPID, QUANTITATIVE BIOASSAY FOR DETECTING PHYTOTOXIC GASES USING STRESS-ETHYLENE

    EPA Science Inventory

    A simple bioassay for detecting phytotoxic air pollutants has been developed. Wheat (Triticum aestivum L.) seedlings growing on agar medium in test-tubes are exposed to pollutants for 2 h. Stress-ethylene produced by the seedlings during exposure to the pollutants is collected in...

  13. DEVELOPMENT OF A TEST-TUBE STRESS-ETHYLENE BIOASSAY FOR DETECTING PHYTOTOXIC GASES

    EPA Science Inventory

    A rapid, quantitative bioassay for detecting phytotoxic air pollutants has been developed. The technique uses wheat Triticum aestivum L. or tomato Lycopersicon esculentum L., seedlings growing on an agar medium in test-tubes. The seedlings are exposed to a pollutant in the test-t...

  14. USE OF SALMONELLA MICROSUSPENSION BIOASSAY TO DETECT THE MUTGENICITY OF MUNITIONS COMPOUNDS AT LOW CONCENTRATIONS

    EPA Science Inventory



    Use of a Salmonella Microsuspension Bioassay to Detect the Mutagenicity of
    Munitions Compounds at Low Concentrations

    Abstract

    Past production and handling of munitions has resulted in soil contamination at various military facilities. Depending on...

  15. Age and sex related responsiveness of Tribolium castaneum (Coleoptera: Tenebrionidae) in novel behavioral bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The hardiness and mobile nature of Tribolium castaneum (Herbst) make them easy to work with but are the same factors that make their responses to behavior modifying chemical stimuli difficult to evaluate. To overcome these difficulties we developed two bioassays: a two choice test with airflow and a...

  16. Effective bioassays for evaluating boxwood blight (Calonectria pseudonaviculata) susceptibility using detached stem inoculations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two simple and rapid in vitro bioassays using detached stems were developed for evaluating the susceptibility of boxwood genotypes to the blight disease caused by Calonectria pseudonaviculata. Individual leaves were inoculated on detached stems or entire detached stems were sprayed to assess suscept...

  17. Kinetic microplate bioassays for relative potency of antibiotics improved by partial Least Square (PLS) regression.

    PubMed

    Francisco, Fabiane Lacerda; Saviano, Alessandro Morais; Almeida, Túlia de Souza Botelho; Lourenço, Felipe Rebello

    2016-05-01

    Microbiological assays are widely used to estimate the relative potencies of antibiotics in order to guarantee the efficacy, safety, and quality of drug products. Despite of the advantages of turbidimetric bioassays when compared to other methods, it has limitations concerning the linearity and range of the dose-response curve determination. Here, we proposed to use partial least squares (PLS) regression to solve these limitations and to improve the prediction of relative potencies of antibiotics. Kinetic-reading microplate turbidimetric bioassays for apramacyin and vancomycin were performed using Escherichia coli (ATCC 8739) and Bacillus subtilis (ATCC 6633), respectively. Microbial growths were measured as absorbance up to 180 and 300min for apramycin and vancomycin turbidimetric bioassays, respectively. Conventional dose-response curves (absorbances or area under the microbial growth curve vs. log of antibiotic concentration) showed significant regression, however there were significant deviation of linearity. Thus, they could not be used for relative potency estimations. PLS regression allowed us to construct a predictive model for estimating the relative potencies of apramycin and vancomycin without over-fitting and it improved the linear range of turbidimetric bioassay. In addition, PLS regression provided predictions of relative potencies equivalent to those obtained from agar diffusion official methods. Therefore, we conclude that PLS regression may be used to estimate the relative potencies of antibiotics with significant advantages when compared to conventional dose-response curve determination. PMID:26971814

  18. Comparison of two bioassay methods for determining deltamethrin resistance in German cockroaches (Blattodea: Blattellidae).

    PubMed

    Choo, L E; Tang, C S; Pang, F Y; Ho, S H

    2000-06-01

    Susceptibility to deltamethrin of 10 strains of the German cockroach, Blattella germanica (L.), trapped in hotel kitchens in Singapore was determined. Two resistance detection bioassay methods (topical application and World Health Organization glass jar method) were compared. Resistance ratios based on 50% knockdown, obtained by comparison with the S strain, ranged from 17.7 to 4,235 for topical application and from 2.2 to 22 for the glass jar method. A field strain, with consistently low resistance ratios (topical method = 17.7, glass jar method = 2.2), was identified as a potential field strain to be used as a baseline for comparison with other field strains. Resistance ratios for the other field strains obtained by comparison with the R5 strain ranged from 24.5 to 239 for topical application and from 1.2 to 9.8 for the glass jar method. The results of our study demonstrate that deltamethrin-resistant German cockroaches are numerous in Singapore. Comparison between the two bioassay methods showed that there was significant correlation between KD50 and KT50 values. The glass jar method is similar to field situations but topical application is sensitive enough to define the magnitude of resistance. Differences between the two detection bioassays and the factors governing the choice of bioassay in monitoring resistance in German cockroaches are discussed. PMID:10902348

  19. Rapid Bioassessment and In Situ Bioassay: Cost Effective Tools for Environmental Impact Assessment

    SciTech Connect

    Wike, L.D.

    2002-08-23

    Environmental impact can be difficult to assess, especially at the ecosystem level. Any impact assessment methodology that can give cost effective and timely results is highly desirable. Rapid bioassessment (RBA) is cost effective and produces timely results. Several types of RBA have been used at the Savannah River Site (SRS) to assess stream conditions, including the Index of Biotic Integrity (IBI) based on fish community characteristics, and various techniques using aquatic macroinvertebrate species diversity and abundance. In an attempt to broaden the applicability of the RBA concept, we have also begun to develop RBA techniques for seep-fed wetlands and terrestrial habitats. These techniques will focus on vertebrate and macroinvertebrate assemblages for seep-fed wetlands and arthropod assemblages for terrestrial habitats. In situ bioassay is another technique that could be used for rapid and economical assessment of the effects of anthropogenic disturbance. We propose the development of two methods of in situ bioassay that can address bioavailability of constituents of concern. The use of caged bioassay organisms can be applied to terrestrial systems such as capped or existing waste sites using the common house cricket. Another proposed bioassay could use a resident species, such as the imported red fire ant, which is found in disturbed habitats and open areas such as waste sites. Combining in situ techniques with RBA methodologies has the potential to provide a comprehensive assessment of chemical and physical impacts to a wide range of ecosystem types.

  20. APPLICATION OF PLANT AND EARTHWORM BIOASSAYS TO EVALUATE REMEDIATION OF A LEAD-CONTAMINATED SOIL

    EPA Science Inventory

    Earthworm acute toxicity, plant seed germination/root elongation (SG/RE) and plant genotoxicity bioassays were employed to evaluate the remediation of a lead-contaminated soil. The remediation involved removal of heavy metals by a soil washing/soil leaching treatment process. A p...

  1. A BIOASSAY THAT IDENTIFIES POSTNATAL FUNCTIONAL DEFICITS IN MICE PRENATALLY EXPOSED TO XENOBIOTICS

    EPA Science Inventory

    Experimental strategies to evaluate adverse postnatal effects due to prenatal exposure exist for many organ systems. Often, however, there is insufficient information to suggest that a particular organ system(s) may be sensitive to the test agent. A single bioassay to identify ...

  2. STS-111 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-08-01

    This video, Part 1 of 4, shows the activities of the STS-111 crew (Kenneth Cockrell, Commander; Paul Lockhart, Pilot; Franklin Chang-Diaz, Phillipe Perrin, Mission Specialists) during flight days 1 through 4. Also shown are the incoming Expedition 5 (Valeri Korzun, Commander; Peggy Whitson, NASA ISS Science Officer; Sergei Treschev, Flight Engineer) and outgoing Expedition 4 (Yuri Onufriyenko, Commander; Carl Walz, Daniel Bursch, Flight Engineers) crews of the ISS (International Space Station). The activities from other flight days can be seen on 'STS-111 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002139469), 'STS-111 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139468), and 'STS-111 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002139474). The primary activity of flight day 1 is the launch of Space Shuttle Endeavour. The crew is seen before the launch at a meal and suit-up, and some pre-flight procedures are shown. Perrin holds a sign with a personalized message. The astronauts communicate with Mission Control extensively after launch, and an inside view of the shuttle cabin is shown. The replays of the launch include close-ups of the nozzles at liftoff, and the fall of the solid rocket boosters and the external fuel tank. Flight day 2 shows footage of mainland Asia at night, and daytime views of the eastern United States and Lake Michigan. Flight day three shows the Endeavour orbiter approaching and docking with the ISS. After the night docking, the crews exchange greetings, and a view of the Nile river and Egypt at night is shown. On flight day 4, the MPLM (Multi-Purpose Logistics Module) Leonardo was temporarily transferred from Endeavour's payload bay to the ISS.

  3. STS-109 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-05-01

    This video, Part 4 of 4, shows footage of crew activities from flight days 8 through 12 of STS-109. The crew included: Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, Richard Linnehan, James Newman, Michael Massimino, Mission Speicalists. The activities from other flights days can be seen on 'STS-109 Mission Highlights Resource Tape' Part 1 of 4 (internal ID 2002139471), 'STS-109 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002137664), and 'STS-109 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139476). The primary activity on flight day 8 was an EVA (extravehicular activity) by Grunsfeld and Linnehan to install a cryocooler and radiator for the NICMOS (Near Infrared Camera and Multi-Object Spectrometer) on the HST (Hubble Space Telescope). Before returning to Columbia's airlock, the astronauts, with a cloudy background, hold onto the orbiter and offer their thoughts on the significance of their mission, the HST, and spaceflight. Footage from flight day 9 includes the grappling, unbearthing, and deployment of the HST from Columbia, and the crew coordinating and videotaping Columbia's departure. Flight day 10 was a relatively inactive day, and flight day 11 includes a checkout of Columbia's aerodynamic surfaces. Columbia landed on flight day 12, which is covered by footage of the crew members speaking during reentry, and their night landing, primarily shown through the orbiter's head-up display. The video includes numerous views of the HST, as well as views of the the Galapagos Islands, Madagascar, and Southern Africa with parts of the Atlantic, Indian, and Pacific Oceans, and part of the coast of Chile. The pistol grip space tool is shown in use, and the crew answers two messages from the public, including a message to Massimino from the Fire Department of New York.

  4. STS-109 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-05-01

    This video, Part 2 of 4, shows the activities of the STS-109 crew (Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, James Newman, Richard Linnehan, Michael Massimino, Mission Specialists) during flight days 4 and 5. The activities from other flights days can be seen on 'STS-109 Mission Highlights Resource Tape' Part 1 of 4 (internal ID 2002139471), 'STS-109 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139476), and 'STS-109 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002137577). The primary activities during these days were EVAs (extravehicular activities) to replace two solar arrays on the HST (Hubble Space Telescope). Footage from flight day 4 records an EVA by Grunsfeld and Linnehan, including their exit from Columbia's payload bay airlock, their stowing of the old HST starboard rigid array on the rigid array carrier in Columbia's payload bay, their attachment of the new array on HST, the installation of a new starboard diode box, and the unfolding of the new array. The pistol grip space tool used to fasten the old array in its new location is shown in use. The video also includes several shots of the HST with Earth in the background. On flight day 5 Newman and Massimino conduct an EVA to change the port side array and diode box on HST. This EVA is very similar to the one on flight day 4, and is covered similarly in the video. A hand operated ratchet is shown in use. In addition to a repeat of the previous tasks, the astronauts change HST's reaction wheel assembly, and because they are ahead of schedule, install installation and lubricate an instrument door on the telescope. The Earth views include a view of Egypt and Israel, with the Nile River, Red Sea, and Mediterranean Sea.

  5. STS-109 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-05-01

    This video, Part 1 of 4, shows the activities of the STS-109 crew (Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, James Newman, Richard Linnehan, Michael Massimino, Mission Specialists) during flight days 1 through 3. The activities from other flight days can be seen on 'STS 109 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002137664), 'STS 109 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139471), and 'STS-109 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002137577). The main activity recorded during flight day 1 is the liftoff of Columbia. Attention is given to suit-up, boarding, and pre-flight procedures. The pre-launch crew meal has no sound. The crew members often wave to the camera before liftoff. The jettisoning of the solid rocket boosters is shown, and the External Tank is seen as it falls to Earth, moving over African dunes in the background. There are liftoff replays, including one from inside the cockpit. The opening of the payload bay doors is seen from the rear of the shuttle's cockpit. The footage from flight day 2 shows the Flight Support System for bearthing the HST (Hubble Space Telescope). Crew preparations for the bearthing are shown. Flight day 3 shows the tracking of and approach to the HST by Columbia, including orbital maneuvers, the capture of the HST, and its lowering onto the Flight Support System. Many views of the HST are shown, including one which reveals an ocean and cloud background as the HST retracts a solar array.

  6. Structural constraints for proposed Fort Hancock low-level radioactive waste disposal site (NTP-S34), southern Hudspeth County, Texas

    SciTech Connect

    Lemone, D.V.

    1989-03-01

    Structural complexities reduce the homogeneity necessary for a site characterization model to an unacceptable level for performance assessment for radioactive waste disposal sites. The proposed site lies between the northern, stable Diablo platform and the southern, mobile Mesozoic Chihuahua tectonic belt. Structural movement along this interface has been active for the past 14,000 years. In addition, the area lies along the northern margin of the Permian Marfa basin and the northeastern margin of the deeply faulted Hueco bolson segment of the late Cenozoic Rio Grande rift system. Recent seismic activity with extensive surface rupture in Quitman Canyon (30 mi southeast of the site) is also documented from the 1931 Valentine, Texas, earthquake (6.4 Richter scale). The site is underlain by either a thrust fault or the complex terminus of a Mesozoic thrust fault. This fault is a segment of the continuous thrust sheet extending from exposures in the Sierra Blanc area, 30 mi east (Devil Ridge fault), to the El Paso area west (Rio Grande fault). This segment of the Devil Ridge-Rio Grande thrust is documented by the Haymond Krupp No. 1 Thaxton wildcat drilled at Campogrande Mountain immediately south of the site. The recent rift fault scarp (Campo Grande) immediately south of the Thaxton well has a 17-mi surface trace and is, no doubt, related to the subsurface Clint fault to the west in the El Paso area. An additional complexity is the presence of a monoclinal flexure with a minimum of 900 ft of surface relief (2 mi northeast of NTP-S34). A 4.5-mi, east-west, down-to-the-south normal fault occurs near the top of the monocline with a small associated graben. These complexities seriously compromise the proposed Fort Hancock site.

  7. Fermi GBM: Highlights from the First Year

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2009-01-01

    The Fermi Gamma ray Burst Monitor is an all-sky instrument sensitive to photons from about 8 keV to 40 MeV. I will summarize highlights from the first year, including triggered observations of gamma ray bursts, soft gamma ray repeaters, and terrestrial gamma flashes, and observations in the continuous data of X-ray binaries and accreting X-ray pulsars. GBM provides complementary observations to Swift/BAT, observing many of the same sources, but over a wider energy range.

  8. Langley aeronautics and space test highlights, 1984

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests which were performed during calendar year 1984 in Langley test facilities are highlighted. The broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research are illustrated.

  9. Highlights in the study of exoplanet atmospheres.

    PubMed

    Burrows, Adam S

    2014-09-18

    Exoplanets are now being discovered in profusion. To understand their character, however, we require spectral models and data. These elements of remote sensing can yield temperatures, compositions and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are made. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has frequently lagged behind ambition. I summarize the most productive, and at times novel, methods used to probe exoplanet atmospheres; highlight some of the most interesting results obtained; and suggest various broad theoretical topics in which further work could pay significant dividends. PMID:25230656

  10. Highlights in Astronomy Education, Outreach, and Heritage

    NASA Astrophysics Data System (ADS)

    Hemenway, Mary

    2015-08-01

    Short talks and a panel discussion by members of the leadership of Division C will highlight important work that has occurred since the last General Assembly. Although a small portion of the session will cover administrative matters of the Division, Commissions, and Working Groups, the focus will be on accomplishments in the broad fields of education, outreach, and heritage. The purpose of the session is to not only inform the audience about a sample of cutting edge projects and methodologies in our fields, but to invite participants to become more involved.

  11. STS-111 Flight Day 4 Highlights Replay

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The most significant highlights of flight day 4 of STS-111 are the lifting of the Leonardo Multi Purpose Logistics Module (MPLM) out of Endeavour's payload bay, and its temporary attachment to the Unity module of the International Space Station (ISS). The lifting and attachment are shown. Also shown is the testing of cameras on the CANADARM2 robotic arm on the ISS, an ISS extravehicular activity (EVA) suit, and an interview with the outgoing Expedition 4 crew of the ISS. Earth views include the ISS and Earth limb, and cloud formations.

  12. Highlights in the study of exoplanet atmospheres

    NASA Astrophysics Data System (ADS)

    Burrows, Adam S.

    2014-09-01

    Exoplanets are now being discovered in profusion. To understand their character, however, we require spectral models and data. These elements of remote sensing can yield temperatures, compositions and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are made. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has frequently lagged behind ambition. I summarize the most productive, and at times novel, methods used to probe exoplanet atmospheres; highlight some of the most interesting results obtained; and suggest various broad theoretical topics in which further work could pay significant dividends.

  13. Paper-based chromatic toxicity bioassay by analysis of bacterial ferricyanide reduction.

    PubMed

    Pujol-Vila, F; Vigués, N; Guerrero-Navarro, A; Jiménez, S; Gómez, D; Fernández, M; Bori, J; Vallès, B; Riva, M C; Muñoz-Berbel, X; Mas, J

    2016-03-01

    Water quality assessment requires a continuous and strict analysis of samples to guarantee compliance with established standards. Nowadays, the increasing number of pollutants and their synergistic effects lead to the development general toxicity bioassays capable to analyse water pollution as a whole. Current general toxicity methods, e.g. Microtox(®), rely on long operation protocols, the use of complex and expensive instrumentation and sample pre-treatment, which should be transported to the laboratory for analysis. These requirements delay sample analysis and hence, the response to avoid an environmental catastrophe. In an attempt to solve it, a fast (15 min) and low-cost toxicity bioassay based on the chromatic changes associated to bacterial ferricyanide reduction is here presented. E. coli cells (used as model bacteria) were stably trapped on low-cost paper matrices (cellulose-based paper discs, PDs) and remained viable for long times (1 month at -20 °C). Apart from bacterial carrier, paper matrices also acted as a fluidic element, allowing fluid management without the need of external pumps. Bioassay evaluation was performed using copper as model toxic agent. Chromatic changes associated to bacterial ferricyanide reduction were determined by three different transduction methods, i.e. (i) optical reflectometry (as reference method), (ii) image analysis and (iii) visual inspection. In all cases, bioassay results (in terms of half maximal effective concentrations, EC50) were in agreement with already reported data, confirming the good performance of the bioassay. The validation of the bioassay was performed by analysis of real samples from natural sources, which were analysed and compared with a reference method (i.e. Microtox). Obtained results showed agreement for about 70% of toxic samples and 80% of non-toxic samples, which may validate the use of this simple and quick protocol in the determination of general toxicity. The minimum instrumentation

  14. EFFECT OF THE OIL DISPERSANT OMNI-CLEAN(R) ON THE TOXICITY OF FUEL OIL NO. 2 IN TWO BIOASSAYS WITH THE SHEEPSHEAD MINNOW CYPRINODON VARIEGATUS

    EPA Science Inventory

    Bioassays (7-day early life stage and 96h acute bioassays) were conducted with the sheepshead minnow, Cyprinodon variegatus, to determine the toxicity of the dispersant Omni-Clean< by itself and in combination with fuel oil no. 2. Performance characteristics of both bioassay type...

  15. Responses of lone star tick (acari: ixodidae) nymphs to the repellent deet applied in acetone and ethanol solutions in vitro bioassays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Behavioral bioassays remain a standard tool in the discovery, development, and registration of repellents. Although tick repellent bioassays tend to be rather uncomplicated, several factors can influence their outcomes. Typically repellent bioassays use a solvent, such as acetone or ethanol, to disp...

  16. Electrogenerated Chemiluminescence Bioassay of Two Protein Kinases Incorporating Peptide Phosphorylation and Versatile Probe.

    PubMed

    Liu, Xia; Dong, Manman; Qi, Honglan; Gao, Qiang; Zhang, Chengxiao

    2016-09-01

    A sensitive electrogenerated chemiluminescence (ECL) bioassay was developed for the detection of two protein kinases incorporating the peptide phosphorylation and a versatile ECL probe. Cyclic adenosine monophosphate-dependent protein kinase (PKA) and casein kinase II (CK2) were used as proof-of-concept targets while a PKA-specific peptide (CLRRASLG) and a CK2-specific peptide (CRRRADDSDDDDD) were used as the recognition substrates. Taking advantage of the ability of protein A binding with the Fc region of a variety of antibodies with high affinity, a ruthenium derivative-labeled protein A was utilized as a versatile ECL probe for bioassay of multiple protein kinases. A specific peptide substrate toward target protein kinase was first self-assembled on the surface of gold electrode and then serine in the specific peptide on the electrode was phosphorylated by target protein kinase in the presence of adenosine-5'-triphosphate. After recognition of the phosphorylated peptide by monoclonal antiphosphoserine antibody, the versatile ECL probe was specifically bound to the antiphosphoserine antibody on the electrode surface. The ECL bioassay was developed successfully in the individual detection of PKA and CK2 with detection limit of 0.005 U/mL and 0.004 U/mL, respectively. In addition, the ECL bioassay was applied to quantitative analysis of the kinase inhibitors and monitoring drug-triggered kinase activation in cell lysates. Moreover, an ECL imaging bioassay using electron-multiplying charged coupled device as detector on the gold electrode array was developed for the simultaneous detection of PKA and CK2 activity from 0.01 U/mL to 0.4 U/mL, respectively, at one time. This work demonstrates that the ingenious design and use of a versatile ECL probe are promising to simultaneous detection of multiple protein kinases and screening of kinase inhibitor. PMID:27518533

  17. Bioassays for the detection of chemicals that can form bioactivation-dependent reactive free radicals

    SciTech Connect

    Sanderson, J.T.; Commandeur, J.N.M.; Wezel, A. van; Vermeulen, N.P.E. . Div. of Molecular Toxicology National Inst. for Coastal and Marine Management, Den Haag )

    1999-06-01

    In vitro bioassays were developed for the detection of chemicals that can be bioactivated to reactive free radical species in microsomal fractions. Two methods were deployed, a down-scaled spectrophotometric method for the detection of chemicals that can cause lipid peroxidation using the measurement of thiobarbituric acid-reactive substances (TBARS) and a fluorometric method for the detection of chemicals that can undergo redox cycling to generate superoxide radicals based on the detection of hydrogen peroxide. The response of these systems to prototypical and environmentally relevant chemicals, including tetrachloromethane and paraquat, was examined. The detection limit of the lipid peroxidation bioassay, based on the formation of TBARS, was about 1 [micro]M for tetrachloromethane; that of the bioassay for redox cyclers, based on the production of hydrogen peroxide, was about 2 [micro]M for paraquat and about 100-fold lower for the potent redox cycler 2,3,5,6-tetramethylbenzoquinone (TMBQ). Several binary mixtures of chemicals were tested for potential nonadditive effects in both in vitro systems. Some antagonistic effects among halogenated methanes were observed in the lipid peroxidation assay. In the hydrogen peroxide production assay, greater than additive effects were seen between small concentrations of paraquat and TMBQ. A number of surface water concentrates from several locations in The Netherlands, with various levels of chemical contamination, exhibited a weak response in the hydrogen peroxide production assay. Acetone was found to interfere with the response of the bioassay to redox cyclers and, therefore, the water concentrates (originally in acetone) were transferred to ethanol prior to testing. A good correlation was observed between the response of the water concentrates in the hydrogen peroxide production assay and their acute toxicity in Daphnia magna. No correlation was observed between this bioassay response and toxicity in the Microtox

  18. The OECD program to validate the rat uterotrophic bioassay. Phase 2: dietary phytoestrogen analyses.

    PubMed Central

    Owens, William; Ashby, John; Odum, Jenny; Onyon, Lesley

    2003-01-01

    Many commercial laboratory diets have detectable levels of isoflavones (e.g., phytoestrogens such as genistein [GN]) that have weak estrogenic activity both in vitro and in vivo. During validation studies of the uterotrophic bioassay, diet samples from 20 participating laboratories were collected and analyzed for three major phytoestrogens: GN, daidzein (DN), and coumestrol (CM). Soy phytoestrogens GN and DN were found at total phytoestrogen levels from 100 to 540 microg/g laboratory diet; a forage phytoestrogen, CM, ranged from nondetectable to 4 microg/g laboratory diet. The phytoestrogen levels were compared with both baseline uterine weights of the control groups and with the relative uterine weight increase of groups administered two weak estrogen agonists: bisphenol A (BPA) and nonylphenol (NP). The comparison uses a working assumption of additivity among the phytoestrogens, despite several significant qualifications to this assumption, to estimate total genistein equivalents (TGE). Some evidence was found that phytoestrogen levels in the diet > 325-350 microg/g TGE could diminish the responsiveness of the uterotrophic bioassay to weak agonists. This was especially true for the case of the intact, immature female version of the uterotrophic bioassay, where higher food consumption relative to body weight leads to higher intakes of dietary phytoestrogens versus ovariectomized adults. This dietary level is sufficient in the immature female to approach a biological lowest observable effect level for GN of 40-50 mg/kg/day. These same data, however, show that low to moderate levels of dietary phytoestrogens do not substantially affect the responsiveness of the assay with weak estrogen receptor agonists such as NP and BPA. Therefore, laboratories conducting the uterotrophic bioassay for either research or regulatory purposes may routinely use diets containing levels of phytoestrogens < 325-350 microg/g TGE without impairing the responsiveness of the bioassay. PMID

  19. Scientific Considerations for Evaluating Cancer Bioassays Conducted by the Ramazzini Institute

    PubMed Central

    Caldwell, Jane C.; Jinot, Jennifer; Evans, Marina V.; Cote, Ila; Vandenberg, John J.

    2013-01-01

    Background: The Ramazzini Institute (RI) has completed nearly 400 cancer bioassays on > 200 compounds. The European Food Safety Authority (EFSA) and others have suggested that study design and protocol differences between the RI and other laboratories by may contribute to controversy regarding cancer hazard findings, principally findings on lymphoma/leukemia diagnoses. Objective: We aimed to evaluate RI study design, protocol differences, and accuracy of tumor diagnoses for their impact on carcinogenic hazard characterization. Methods: We analyzed the findings from a recent Pathology Working Group (PWG) review of RI procedures and tumor diagnoses, evaluated consistency of RI and other laboratory findings for chemicals identified by the RI as positive for lymphoma/leukemia, and examined evidence for a number of other issues raised regarding RI bioassays. The RI cancer bioassay design and protocols were evaluated in the context of relevant risk assessment guidance from international authorities. Discussion: Although the PWG identified close agreement with RI diagnoses for most tumor types, it did not find close agreement for lymphoma/leukemia of the respiratory tract or for neoplasms of the inner ear and cranium. Here we discuss a) the implications of the PWG findings, particularly lymphoma diagnostic issues; b) differences between RI studies and those from other laboratories that are relevant to evaluating RI cancer bioassays; and c) future work that may help resolve some concerns. Conclusions: We concluded that a) issues related to respiratory tract infections have complicated diagnoses at that site (i.e., lymphoma/leukemia), as well as for neoplasms of the inner ear and cranium, and b) there is consistency and value in RI studies for identification of other chemical-related neoplasia. Citation: Gift JS, Caldwell JC, Jinot J, Evans MV, Cote I, Vandenberg JJ. 2013. Scientific considerations for evaluating cancer bioassays conducted by the Ramazzini Institute

  20. Introducing Open Highlights: Highlighting Open Access Research from PLOS and Beyond.

    PubMed

    2016-07-01

    PLOS Biology announces a new article type, Open Highlights, which uses a recent research article to nucleate a short synthesis of up to ten related research articles from other PLOS journals and from the wider Open Access corpus. PMID:27400228