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Sample records for fluorometers

  1. Pulse amplitude modulated chlorophyll fluorometer

    DOEpatents

    Greenbaum, Elias; Wu, Jie

    2015-12-29

    Chlorophyll fluorometry may be used for detecting toxins in a sample because of changes in micro algae. A portable lab on a chip ("LOAC") based chlorophyll fluorometer may be used for toxin detection and environmental monitoring. In particular, the system may include a microfluidic pulse amplitude modulated ("PAM") chlorophyll fluorometer. The LOAC PAM chlorophyll fluorometer may analyze microalgae and cyanobacteria that grow naturally in source drinking water.

  2. Tolerancing fluorometers for in-vitro diagnostics

    NASA Astrophysics Data System (ADS)

    Heinz, Eric

    2009-02-01

    Anyone can make a fluorometer. All that is needed is a light source, a detector, some filters and maybe some lenses. For commercial clinical instruments, however, our customers demand stability, reliability, and reproducibility. If research instruments are like race cars, commercial instruments should be like trucks. This demands that our fluorometer designs be carefully toleranced. This paper will discuss causes of variation and drift, and ways to make fluorometers that are stable and reproducible.

  3. Multiple protocol fluorometer and method

    DOEpatents

    Kolber, Zbigniew S.; Falkowski, Paul G.

    2000-09-19

    A multiple protocol fluorometer measures photosynthetic parameters of phytoplankton and higher plants using actively stimulated fluorescence protocols. The measured parameters include spectrally-resolved functional and optical absorption cross sections of PSII, extent of energy transfer between reaction centers of PSII, F.sub.0 (minimal), F.sub.m (maximal) and F.sub.v (variable) components of PSII fluorescence, photochemical and non-photochemical quenching, size of the plastoquinone (PQ) pool, and the kinetics of electron transport between Q.sub.a and PQ pool and between PQ pool and PSI. The multiple protocol fluorometer, in one embodiment, is equipped with an excitation source having a controlled spectral output range between 420 nm and 555 nm and capable of generating flashlets having a duration of 0.125-32 .mu.s, an interval between 0.5 .mu.s and 2 seconds, and peak optical power of up to 2 W/cm.sup.2. The excitation source is also capable of generating, simultaneous with the flashlets, a controlled continuous, background illumination.

  4. Solid state fluorometer: Prototype development

    NASA Astrophysics Data System (ADS)

    Czarnaski, Joseph; Foster, Karen; Hardgrove, John; Oprison, Richard; Hickman, James

    1994-03-01

    The development of new detectors for chemical and biological warfare agents is of interest to the DOD. One way to detect these agents is by fluorescent labeling of one of the species involved in a binding event. The U.S. Air Force has developed a system that combines a biological assay with a fluorescent molecule tag. The binding event is quantified by measuring the ratio of red to green fluorescence. With a solid state fluorometer fast binding detection is possible in a small, lightweight package that could easily be interfaced to a microprocessor with readout. We have begun the development of a solid state microfluorometer. The development has been divided into three phases: (1) prototype development, (2) device operational parameter investigation, and (3) design and construction. This report details the construction of the prototype device. The prototype has a 488-nm laser for excitation, and red and green detectors for fluorescent emission. The calibration of the detectors and the computer interface construction is described. It can be used as a fluorescent imaging system as well.

  5. 21 CFR 862.2560 - Fluorometer for clinical use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Fluorometer for clinical use. 862.2560 Section 862...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2560 Fluorometer for clinical use. (a) Identification. A fluorometer for clinical use is a...

  6. 21 CFR 862.2560 - Fluorometer for clinical use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Fluorometer for clinical use. 862.2560 Section 862.2560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2560 Fluorometer for clinical use. (a) Identification. A fluorometer for clinical use is a device...

  7. The Fraunhofer line discriminator: An airborne fluorometer

    NASA Technical Reports Server (NTRS)

    Stoertz, G. E.

    1969-01-01

    An experimental Fraunhofer Line Discriminator (FLD) can differentiate and measure solar-stimulated luminescence when viewed against a background of reflected light. Key elements are two extremely sensitive photomultipliers, two glass-spaced Fabry-Perot filters having a bandwidth less than 1 A, and an analog computer. As in conventional fluorometers, concentration of a fluorescent substance is measured by comparison with standards. Quantitative use is probably accurate only at low altitudes but detection of luminescent substances should be possible from any altitude. Applications of the present FLD include remote sensing of fluorescent dyes used in studies of current dynamics. The basic technique is applicable to detection of oil spills, monitoring of pollutants, and sensing over land areas.

  8. 2-GHz frequency-domain fluorometer

    NASA Astrophysics Data System (ADS)

    Lakowicz, Joseph R.; Laczko, Gabor; Gryczynski, Ignacy

    1986-10-01

    We developed a frequency-domain fluorometer which operates from 4 to 2000 MHz. The modulated excitation is provided by the harmonic content of a laser pulse train (3.76 MHz, 5 ps) from a synchronously pumped and cavity dumped dye laser. The phase angle and modulation of the emission are measured with a microchannel-plate photomultiplier (PMT). Cross-correlation detection is performed outside the PMT. The high-frequency signals for cross correlation were obtained by multiplication of the output from a 500-MHz frequency synthesizer. The performance was verified in several ways, including measurement of known time delays and examination of standard fluorophores. The detector displayed no detectable color effect, with the 300-600-nm difference being less than 5 ps. The precision of the measurements is adequate to detect differences of 20 ps for decay times of 500 ps. A correlation time of 53 ps was found for indole in water at 20 °C. The shortest correlation time we measured was 15 ps for indole in methanol/water (75/25) at 40 °C. Also, the 2-GHz data reveal the time-dependent ((t)1/2) terms found in the presence of collisional quenching. The degree of random error is about 0.3° of phase and 0.005 in modulation throughout the frequency range.

  9. Three color laser fluorometer for studies of phytoplankton fluorescence

    NASA Technical Reports Server (NTRS)

    Phinney, David A.; Yentsch, C. S.; Rohrer, J.

    1988-01-01

    A three-color laser fluorometer has been developed for field work operations. Using two tunable dye lasers (excitation wavelengths at 440 nm and 530 nm), broadband wavelength optical filters were selected to obtain maximum fluorescence sensitivity at wavelengths greater than 675 nm (chlorophyll) and 575 + or - 15 nm (phycoerythrin). The laser fluorometer permits the measurement of phytoplankton pigments under static or flowing conditions and more closely resembles the time scales (ns) and energy levels (mW) of other laser-induced fluorescence instruments.

  10. Multiple excitation fluorometer for in situ oceanographic applications.

    PubMed

    Desiderio, R A; Moore, C; Lantz, C; Cowles, T J

    1997-02-20

    A new in situ fluorometer for the detection of oceanic photosynthetic pigment fluorescence is described. Emission spectra from 546 to 733 nm are recorded for each of three different visible excitation bands ten times a second. A Spectralon cell is used to improve the excitation coupling to and the collection efficiency from the sample volume. Laboratory tests demonstrated that the fluorescence emission spectra from the violet, blue, and green excitation can be used to discriminate among various algal species. The instrument was used at sea in extended in situ deployments on an undulating vehicle (SeaSoar).

  11. Computer controlled fluorometer device and method of operating same

    DOEpatents

    Kolber, Z.; Falkowski, P.

    1990-07-17

    A computer controlled fluorometer device and method of operating same, said device being made to include a pump flash source and a probe flash source and one or more sample chambers in combination with a light condenser lens system and associated filters and reflectors and collimators, as well as signal conditioning and monitoring means and a programmable computer means and a software programmable source of background irradiance that is operable according to the method of the invention to rapidly, efficiently and accurately measure photosynthetic activity by precisely monitoring and recording changes in fluorescence yield produced by a controlled series of predetermined cycles of probe and pump flashes from the respective probe and pump sources that are controlled by the computer means. 13 figs.

  12. Computer controlled fluorometer device and method of operating same

    DOEpatents

    Kolber, Zbigniew; Falkowski, Paul

    1990-01-01

    A computer controlled fluorometer device and method of operating same, said device being made to include a pump flash source and a probe flash source and one or more sample chambers in combination with a light condenser lens system and associated filters and reflectors and collimators, as well as signal conditioning and monitoring means and a programmable computer means and a software programmable source of background irradiance that is operable according to the method of the invention to rapidly, efficiently and accurately measure photosynthetic activity by precisely monitoring and recording changes in fluorescence yield produced by a controlled series of predetermined cycles of probe and pump flashes from the respective probe and pump sources that are controlled by the computer means.

  13. Optically Sectioning Ocular Fluorometer Microscope: Applications To The Cornea

    NASA Astrophysics Data System (ADS)

    Masters, Barry R.

    1988-06-01

    An optically sectioning ocular fluorometer microscope is described with the capability of measuring the emission spectra of molecules in planes along the microscope axis. Its unique feature is that the objective is attached to a piezoelectric driver and scans from the tear film to the aqueous humor. This permits measurements on living animals and adoption for clinical use. The excitation light from a laser (nitrogen, dye, argon or helium cadmium) couples to the microscope via a quartz optical fiber. The light is projected through a 100 PM slit on the excitation side, through one half of the objective. The emitted light is collected by the second half of the objective and passes a second 100 pm slit in the conjugate plane of the eyepiece. The depth resolution is 6 um with an 100x objective, and 18 PM with a 50 power objective. The fluorescence is coupled by a quartz fiber to an optical spectrum analyzer. It consists of a monochromator with two microchannel plates attached to a linear diode array. The photocathode of the detector is gated for use with pulsed lasers or it can operate in the continuous mode. The applications include fluorescence measurements on thin layered structures. The present study involves the noninvasive measurement of oxidative metabolism of the component layers of the in vivo cornea. This is based on fluorescence measurements of the reduced pyridine nucleotide in the cornea. The fluorescence signals from the corneal epithelial (30 μm) and endothelial (4 μm) are clearly defined. Other applications to ophthalmology include studies of the fluorescence form the component layers of the ocular lens. Support from N.I.I. EY06958.

  14. High-speed, FPGA-based photon-counting fluorometer with high data-gathering efficiency

    NASA Astrophysics Data System (ADS)

    Iwata, Tetsuo; Mizuno, Takahiko

    2017-07-01

    We have developed a low-cost, high-efficiency fluorometer using a field-programmable gate array and simultaneous detection of photoelectron pulse trains. The fluorometer covers a time span of 64 ns with a resolution of 1.0 ns/channel. Depending on the number of channels, the signal-gathering efficiency was improved by a factor of 100 relative to that of conventional time-correlated single-photon counting. This assumes that the fluorescence intensity is moderately high but still requires photon counting. The dead time for building a histogram has been reduced to zero, which means that the upper limit of the repetitive excitation frequency could exceed that determined by the time span. We describe instrumental details and demonstrate the basic performance.

  15. An Evaluation of an In Situ Fluorometer for the Estimation of Chlorophyll a

    DTIC Science & Technology

    1993-05-01

    acidification ) was measured on a Turner 111 fluorometer calibrated using pure chlorophyll a. Laboratory Calibration. For the phytoplankton culture, we used...Whitledge and Wirick, 1983; Weller et al., 1985; Marra et al. 1990) and in lakes (e.g., Heaney, 1978; Abbott et al., 1982). However, worries have...indicative of photoadaptation of the phytoplankton populations (Fig. 1). The data from OC3 are perhaps clearest in showing a pure fluorescence maximum

  16. A compact field fluorometer and its application to dye tracing in karst environments

    NASA Astrophysics Data System (ADS)

    Poulain, Amaël; Rochez, Gaëtan; Van Roy, Jean-Pierre; Dewaide, Lorraine; Hallet, Vincent; De Sadelaer, Geert

    2017-08-01

    Dye tracing is a classic technique in hydrogeology to investigate surface-water or groundwater flow characteristics, and it is useful for many applications including natural or industrial issues. The Fluo-Green field fluorometer has been successfully tested in a karst environment and is specifically suitable for in-cave karst water monitoring. Karst research often uses dyes to obtain information about groundwater flow in unexplored cave passages. The compact device, alternatively named Fluo-G, meets the requirements of cave media: small (10 × 16 × 21 cm), lightweight (0.75 kg without ballast) and simple in conception. It is easy for cavers to set up and handle compared to other sampling methods. The fluorometer records uranine, turbidity and temperature with a user-defined time-step (1 min - 1 day). Very low energy consumption allows 9,000 measurements with six AA batteries. The device was calibrated and tested in the laboratory and in field conditions in Belgian karst systems. Results are in good fit with other sampling methods: in-situ fluorometers and automatic water sampling plus laboratory analysis. Recording high quality data (breakthrough curves) in karst with in-cave monitoring is valuable to improve knowledge of karst systems. Many hydrological and hydrogeological applications can benefit from such a low-cost and compact device, and finding the best compromise between resources and quality data is essential. Several improvements are possible but preliminary field tests are very promising.

  17. A compact field fluorometer and its application to dye tracing in karst environments

    NASA Astrophysics Data System (ADS)

    Poulain, Amaël; Rochez, Gaëtan; Van Roy, Jean-Pierre; Dewaide, Lorraine; Hallet, Vincent; De Sadelaer, Geert

    2017-03-01

    Dye tracing is a classic technique in hydrogeology to investigate surface-water or groundwater flow characteristics, and it is useful for many applications including natural or industrial issues. The Fluo-Green field fluorometer has been successfully tested in a karst environment and is specifically suitable for in-cave karst water monitoring. Karst research often uses dyes to obtain information about groundwater flow in unexplored cave passages. The compact device, alternatively named Fluo-G, meets the requirements of cave media: small (10 × 16 × 21 cm), lightweight (0.75 kg without ballast) and simple in conception. It is easy for cavers to set up and handle compared to other sampling methods. The fluorometer records uranine, turbidity and temperature with a user-defined time-step (1 min - 1 day). Very low energy consumption allows 9,000 measurements with six AA batteries. The device was calibrated and tested in the laboratory and in field conditions in Belgian karst systems. Results are in good fit with other sampling methods: in-situ fluorometers and automatic water sampling plus laboratory analysis. Recording high quality data (breakthrough curves) in karst with in-cave monitoring is valuable to improve knowledge of karst systems. Many hydrological and hydrogeological applications can benefit from such a low-cost and compact device, and finding the best compromise between resources and quality data is essential. Several improvements are possible but preliminary field tests are very promising.

  18. Fast repetition rate (FRR) fluorometer and method for measuring fluorescence and photosynthetic parameters

    DOEpatents

    Kolber, Z.; Falkowski, P.

    1995-06-20

    A fast repetition rate fluorometer device and method for measuring in vivo fluorescence of phytoplankton or higher plants chlorophyll and photosynthetic parameters of phytoplankton or higher plants is revealed. The phytoplankton or higher plants are illuminated with a series of fast repetition rate excitation flashes effective to bring about and measure resultant changes in fluorescence yield of their Photosystem II. The series of fast repetition rate excitation flashes has a predetermined energy per flash and a rate greater than 10,000 Hz. Also, disclosed is a flasher circuit for producing the series of fast repetition rate flashes. 14 figs.

  19. Fast repetition rate (FRR) fluorometer and method for measuring fluorescence and photosynthetic parameters

    DOEpatents

    Kolber, Zbigniew; Falkowski, Paul

    1995-06-20

    A fast repetition rate fluorometer device and method for measuring in vivo fluorescence of phytoplankton or higher plants chlorophyll and photosynthetic parameters of phytoplankton or higher plants by illuminating the phytoplankton or higher plants with a series of fast repetition rate excitation flashes effective to bring about and measure resultant changes in fluorescence yield of their Photosystem II. The series of fast repetition rate excitation flashes has a predetermined energy per flash and a rate greater than 10,000 Hz. Also, disclosed is a flasher circuit for producing the series of fast repetition rate flashes.

  20. Development of a multi-sensor in situ fiber optic fluorometer

    SciTech Connect

    Lohrenz, S.E.; Asper, V.L. . Center for Marine Sciences); Morris, M.J.; Walters, R.A. )

    1992-12-01

    Objective is to develop and evaluate a multi-sensor in situ fiber optic fluorometer. The instrument is designed to sample and store in vivo strobe-stimulated fluorescence data at multiple depths and high frequencies (1 Hz). This information may be used for estimating the distribution and abundance of particulate pigment biomass, for supporting models of water column primary production and as a complement to remotely sensed ocean color estimates of pigment biomass. The instrument is unique in that it uses fiber optic technology to increase vertical resolution. While it is theoretically possible to accomplish this task using a large number of commercially available fluorometers, our proposed design would provide a less expensive approach. A laboratory prototype has been built and is being tested. Preliminary results indicate that the instrument meets all the project goals and that low cost, high frequency, high spatial resolution chlorophyll data are obtainable with the current design. Further work is required to develop the seagoing version, and optimize the configuration of the fiber sensors.

  1. Methods and Best Practice to Intercompare Dissolved Oxygen Sensors and Fluorometers/Turbidimeters for Oceanographic Applications

    PubMed Central

    Pensieri, Sara; Bozzano, Roberto; Schiano, M. Elisabetta; Ntoumas, Manolis; Potiris, Emmanouil; Frangoulis, Constantin; Podaras, Dimitrios; Petihakis, George

    2016-01-01

    In European seas, ocean monitoring strategies in terms of key parameters, space and time scale vary widely for a range of technical and economic reasons. Nonetheless, the growing interest in the ocean interior promotes the investigation of processes such as oxygen consumption, primary productivity and ocean acidity requiring that close attention is paid to the instruments in terms of measurement setup, configuration, calibration, maintenance procedures and quality assessment. To this aim, two separate hardware and software tools were developed in order to test and simultaneously intercompare several oxygen probes and fluorometers/turbidimeters, respectively in the same environmental conditions, with a configuration as close as possible to real in-situ deployment. The chamber designed to perform chlorophyll-a and turbidity tests allowed for the simultaneous acquisition of analogue and digital signals of several sensors at the same time, so it was sufficiently compact to be used in both laboratory and onboard vessels. Methodologies and best practice committed to the intercomparison of dissolved oxygen sensors and fluorometers/turbidimeters have been used, which aid in the promotion of interoperability to access key infrastructures, such as ocean observatories and calibration facilities. Results from laboratory tests as well as field tests in the Mediterranean Sea are presented. PMID:27196908

  2. Detection of water quality parameters in Hangzhou Bay using a portable laser fluorometer.

    PubMed

    Chen, Peng; Pan, Delu; Mao, Zhihua; Tao, Bangyi

    2015-04-15

    A field, light-weight laser fluorometer based on the method of laser induced fluorescence was developed for water quality monitoring. The basic instrument configuration uses a high pulse repetition frequency microchip laser, a confocal reflective fluorescent probe and a broadband hyperspectral micro spectrometer; it weights only about 1.7 kg. Simultaneous estimates of three important water quality parameters, namely, chlorophyll a (chl-a), colored dissolved organic matter (CDOM), and total suspended matter (TSM) measured by the laser fluorometer were observed to agree well with those measured by traditional methods (0.27-0.84 μg L(-3) chl-a, R(2)=0.88; 0.104-0.295 m(-)(1) CDOM absorption, R(2)=0.90; and 59.8-994.9 mg L(-)(3) TSM, R(2)=0.86) in Hangzhou Bay water. Subsequently, distribution and characteristics of CDOM and chl-a laser fluorescence in Hangzhou Bay were analyzed, which will enhance our understanding of biogeochemical processes in this complex estuarine system at high-resolution, high-frequency and long-term scale. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Development of miniaturized submersible fluorometers for the detection of aromatic hydrocarbons in marine waters

    NASA Astrophysics Data System (ADS)

    Tedetti, Marc; Bachet, Caroline; Joffre, Pascal; Ferretto, Nicolas; Guigue, Catherine; Goutx, Madeleine

    2014-05-01

    Polycyclic aromatic hydrocarbons (PAHs) are among the most widespread organic contaminants in aquatic environments. Due to their physico-chemical properties, PAHs are persistent and mobile, can strongly bioaccumulate in food chains and are harmful to living organisms. They are thus recognized by various international organizations as priority contaminants and are included in the list of 45 priority regulated substances by the European Union. Because of their aromatic structure, PAHs are "optically active" and have inherent fluorescence properties in the ultraviolet (UV) spectral domain (200-400 nm). Therefore, UV fluorescence spectroscopy has been successfully used to develop PAH sensors (i.e. UV fluorometers). Currently, five UV submersible fluorometers are commercially available for in situ measurements of PAHs: EnviroFlu-HC (TriOS Optical Sensors, Germany), Hydrocarbon Fluorometer (Sea & Sun Technology, Germany), HydroC ™ / PAH (CONTROS, Germany), UviLux AquaTracka (Chelsea Technology Group, UK) and Cyclops-7 (Turner Designs, US). These UV fluorometers are all dedicated to the measurement of phenanthrene (λEx /λEm: 255/360 nm), one of the most abundant and fluorescent PAHs found in the aquatic environment. In this study, we developed original, miniaturized submersible fluorometers based on deep UV light-emitting diodes (LEDs) for simultaneous measurements of two PAHs of interest: the MiniFluo-UV 1 for the detection of phenanthrene (PHE, at λEx /λEm: 255/360 nm) and naphthalene (NAP, at λEx /λEm: 270/340 nm), and the MiniFluo-UV 2 for the detection of fluorene (FLU, at λEx /λEm: 255/315 nm) and pyrene (PYR, at λEx /λEm: 270/380 nm). The MiniFluo-UV sensors have several features: measurements of two PAHs at the same time, small size (puck format, 80 x 60 mm), very low energy consumption (500 mW at 12V), LED monitoring, analog and numerical communication modes. The two MiniFluo-UV sensors were first tested in the laboratory: 1) on standard solutions of

  4. Fluorometer with a quartz-rod waveguide-integrating sphere configuration to measure evanescent-field luminescence

    USDA-ARS?s Scientific Manuscript database

    A fluorometer was designed to measure evanescent-field luminescence. A quartz-rod waveguide (d = 2 mm) was installed coaxally inside a cylindrical flow-through cell (id = 2.3 mm, od = 6.3 mm, l = 116 mm). An excitation beam from a UV LED or a miniature xenon flashlamp was focused by a ball lens and ...

  5. A 4-GHz frequency-domain fluorometer with internal microchannel plate photomultiplier cross-correlation.

    PubMed

    Berndt, K W; Gryczynski, I; Lakowicz, J R

    1991-01-01

    We have developed and tested a multifrequency phase/modulation fluorometer based on the Hamamatsu Model R2024U gatable microchannel plate photomultiplier (MCP-PMT), using internal MCP-PMT cross-correlation. This internal mixing is accomplished by biasing and modulating the gating mesh which is located 0.2 mm behind the photocathode. Near the photocathode center, no high-frequency photocurrent modulation was achieved. Within a circular area near the photocathode edge, however, the R2024U allows accurate phase shift and demodulation measurements up to at least 4.5 GHz, the frequency limit of our PMT-modulation amplifier. By mixing immediately after the photocathode, there is no decrease in the time resolution due to transit time spread, and the MCP has to process only low-frequency signals. This means no low-level high-frequency signal voltages have to be handled in this fluorometer, and the problems of RF shielding become much less critical. Also, the effective output impedance of the PMT has been increased, resulting in a 43-dB increase in the PMT output signal power. In principle, more MCPs could be built into the PMT, allowing an improved fluorescence detection limit. We have used the method of reference fluorophores in order to compensate for pronounced PMT color effects, a wavelength-dependent modulation, and a wavelength-dependent time shift. No color correction is required in the case of time-dependent depolarization. The performance of the instrument was verified by measurements of the intensity decay of perylene, which showed a single-exponential decay, and by measurements of the decay of tryptophan in water, which showed a double-exponential decay, as expected.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Utilization of a submersible UV fluorometer for monitoring anthropogenic inputs in the Mediterranean coastal waters.

    PubMed

    Tedetti, Marc; Guigue, Catherine; Goutx, Madeleine

    2010-03-01

    We evaluated the performances of a submersible ultraviolet fluorometer (EnviroFlu-HC, TriOS Optical Sensors) dedicated to the real time measurement of polycyclic aromatic hydrocarbons (PAHs) in the aquatic media. We conducted calibration experiments and in situ measurements in the coastal Mediterranean Sea. We found that the EnviroFlu-HC was not strictly specific to PAHs, even though it exhibited the highest sensitivity for phenanthrene, but could response to tryptophan-like material as well, and in a much less extent, to humic substances. The sensor signal showed great spatial and temporal variations in clean and polluted sites, with likely a high contribution of PAHs in the harbors, and a high contribution of tryptophan-like and humic-like materials in the sewage effluent. We conclude that the EnviroFlu-HC is a good tool for monitoring anthropogenic inputs in the coastal waters, although its utilization should be combined to other fluorescence measurements to improve the information about the nature of the aromatic compounds detected. Copyright 2009 Elsevier Ltd. All rights reserved.

  7. Photon-counting 1.0 GHz-phase-modulation fluorometer

    SciTech Connect

    Mizuno, T.; Nakao, S.; Mizutani, Y.; Iwata, T.

    2015-04-15

    We have constructed an improved version of a photon-counting phase-modulation fluorometer (PC-PMF) with a maximum modulation frequency of 1.0 GHz, where a phase domain measurement is conducted with a time-correlated single-photon-counting electronics. While the basic concept of the PC-PMF has been reported previously by one of the authors, little attention has been paid to its significance, other than its weak fluorescence measurement capability. Recently, we have recognized the importance of the PC-PMF and its potential for fluorescence lifetime measurements. One important aspect of the PC-PMF is that it enables us to perform high-speed measurements that exceed the frequency bandwidths of the photomultiplier tubes that are commonly used as fluorescence detectors. We describe the advantages of the PC-PMF and demonstrate its usefulness based on fundamental performance tests. In our new version of the PC-PMF, we have used a laser diode (LD) as an excitation light source rather than the light-emitting diode that was used in the primary version. We have also designed a simple and stable LD driver to modulate the device. Additionally, we have obtained a sinusoidal histogram waveform that has multiple cycles within a time span to be measured, which is indispensable for precise phase measurements. With focus on the fluorescence intensity and the resolution time, we have compared the performance of the PC-PMF with that of a conventional PMF using the analogue light detection method.

  8. Effect of biofilm on fluorescence measurements derived from fast repetition rate fluorometers.

    PubMed

    Patil, Jagadish S; Saino, Toshiro

    2015-01-01

    This study evaluates, for the first time, the influence of biofilms on single and double optical window (SOW and DOW, respectively) fast repetition rate fluorometer (FRRF) measurements of microalgal photosystem-II initial fluorescence (F0), maximum fluorescence (Fm), variable fluorescence (Fv = Fm - F0), quantum yield (Fv/Fm) and functional absorption cross section (σPSII)]. Biofilms with chlorophyll > 0.1 μg cm(-2) and > 0.3 μgcm(-2) on SOW and DOW, respectively, produced a substantial increase in fluorescence. However, the relative magnitude of biofouling effects depended on sample chlorophyll concentrations, being more critical at concentrations < 1 mg m(-3). In DOW-FRRF, biofilms affected F0 (increased) and Fv/Fm (decreased) but not Fv and σPSII, whereas in SOW-FRRF, biofilms increased fluorescence and showed a variable effect on Fv/Fm and σPSII, because only biofilms on SOW attained actual Fm. As a result, the biofilm effect was substantial on SOW-FRRF measurements. On the other hand, the neutral-density filters (representing non-chlorophyll containing biofilms) with different transmission levels reduced the fluorescence signal. Correction procedures for the above photosystem-II parameters are proposed here.

  9. Measurements of fluorescence lifetimes by use of a hybrid time-correlated and multifrequency phase fluorometer.

    PubMed

    Hedstrom, J; Sedarous, S; Prendergast, F G

    1988-08-23

    Measurements of homogeneous and heterogeneous fluorescence intensity decays using a hybrid time-correlated single photon counting/multifrequency phase fluorometer are reported. A trio of fluorophores exhibiting a range of decay profiles was selected. p-Terphenyl, 1,4-bis[2-(4-methyl-5-phenyloxazolyl)]benzene [(Me)2POPOP], and p-bis[2-(5-phenyloxazolyl)]benzene (POPOP), commonly used reference fluorophores, were analyzed initially; their emissions were characterized by monoexponential decay functions. Additionally, emissions from two single tryptophan proteins with different decay profiles were measured. Scorpion neurotoxin variant 3 required three exponentials to fit the emission decay properly (average lifetime approximately 500 ps). At pH 5.5, the fluorescence emission of ribonuclease T1 showed a monoexponential decay with a measured lifetime of approximately 4.0 ns. Thus, in each case, the results from both measurements were consistent between the two detection systems, confirming the view that the two approaches for measuring fluorescence lifetimes are equivalent.

  10. DNA aptamer beacon assay for C-telopeptide and handheld fluorometer to monitor bone resorption.

    PubMed

    Bruno, John Gordon; Carrillo, Maria P; Phillips, Taylor; Hanson, Douglas; Bohmann, Jonathan A

    2011-09-01

    A novel DNA aptamer beacon is described for quantification of a 26-amino acid C-telopeptide (CTx) of human type I bone collagen. One aptamer sequence and its reverse complement dominated the aptamer pool (31.6% of sequenced clones). Secondary structures of these aptamers were examined for potential binding pockets. Three-dimensional computer models which analyzed docking topologies and binding energies were in agreement with empirical fluorescence experiments used to select one candidate loop for beacon assay development. All loop structures from the aptamer finalists were end-labeled with TYE 665 and Iowa Black quencher for comparison of beacon fluorescence levels as a function of CTx concentration. The optimal beacon, designated CTx 2R-2h yielded a low ng/ml limit of detection using a commercially available handheld fluorometer. The CTx aptamer beacon bound full-length 26-amino acid CTx peptide, but not a shorter 8-amino acid segment of CTx peptide which is a common target for commercial CTx ELISA kits. The prototype assay was shown to detect CTx peptide from human urine after creatinine and urea were removed by size-exclusion chromatography to prevent nonspecific denaturing of the aptamer beacon. This work demonstrates the potential of aptamer beacons to be utilized for rapid and sensitive bone health monitoring in a handheld or point-of-care format.

  11. In situ tryptophan-like fluorometers: assessing turbidity and temperature effects for freshwater applications.

    PubMed

    Khamis, K; Sorensen, J P R; Bradley, C; Hannah, D M; Lapworth, D J; Stevens, R

    2015-04-01

    Tryptophan-like fluorescence (TLF) is an indicator of human influence on water quality as TLF peaks are associated with the input of labile organic carbon (e.g. sewage or farm waste) and its microbial breakdown. Hence, real-time measurement of TLF could be particularly useful for monitoring water quality at a higher temporal resolution than available hitherto. However, current understanding of TLF quenching/interference is limited for field deployable sensors. We present results from a rigorous test of two commercially available submersible tryptophan fluorometers (ex ∼ 285, em ∼ 350). Temperature quenching and turbidity interference were quantified in the laboratory and compensation algorithms developed. Field trials were then undertaken involving: (i) an extended deployment (28 days) in a small urban stream; and, (ii) depth profiling of an urban multi-level borehole. TLF was inversely related to water temperature (regression slope range: -1.57 to -2.50). Sediment particle size was identified as an important control on the turbidity specific TLF response, with signal amplification apparent <150 NTU for clay particles and <650 NTU for silt particles. Signal attenuation was only observed >200 NTU for clay particles. Compensation algorithms significantly improved agreement between in situ and laboratory readings for baseflow and storm conditions in the stream. For the groundwater trial, there was an excellent agreement between laboratory and raw in situ TLF; temperature compensation provided only a marginal improvement, and turbidity corrections were unnecessary. These findings highlight the potential utility of real time TLF monitoring for a range of environmental applications (e.g. tracing polluting sources and monitoring groundwater contamination). However, in situations where high/variable suspended sediment loads or rapid changes in temperature are anticipated concurrent monitoring of turbidity and temperature is required and site specific calibration is

  12. Optics and experimental resolution of the Heidelberg slit-scan flow fluorometer

    NASA Astrophysics Data System (ADS)

    Hausmann, Michael; Wickert, Burkhard; Vogel, Michael; Schurwanz, Michael; Doelle, Juergen; Wolf, Dietmar; Aldinger, Klaus; Cremer, Christoph G.

    1996-01-01

    Slit-scan flow fluorometry is a laser-technological approach for accelerated screening and sorting of fluorescence labelled metaphase chromosomes. Details of the optics of the Heidelberg slit-scan sorter are presented. In a fluid stream the fluorescence labelled chromosomes rapidly pass one at a time by a scanning laser beam. The laser can be focused by a less complex optic consisting of only a few commercially available lenses. The laser intensity distribution around the focus was measured for 488 nm for two lens configurations. Although the light distribution obtained by such an optic is normally not aberration free, the requirements of a 'ribbonlike' shape in the center of the fluid stream can be fulfilled. Since the chromosomes are oriented perpendicularly to the laser beam by hydrodynamic focusing of the fluid stream, the fluorescence intensity along the chromosome axis can be measured time (equals spatially) resolved. According to their intensity profiles the chromosomes can be classified. Signal processing of the profiles can be performed in less than 600 microseconds, so that in the order of hundred chromosomes per second can be sorted out by a computer controlled electro-acoustic sorting unit. The final spatial resolution of a slit-scan flow sorter is not only affected by the focusing optics of the laser but also by the fluid stream, the detection optics and electronics, as well as by the computer analysis algorithm. Calculations often consider only the optics under ideal conditions. Here, a method is shown how to estimate the overall resolution of a slit-scan flow fluorometer experimentally. According to this criterion the resolution of the Heidelberg slit-scan sorter for 488 nm fluorescence excitation was estimated to be 2.4 micrometer in its basic optical configuration and 1.7 micrometer with additional correction of chromatic aberration effects.

  13. Preliminary evaluation of an in vivo fluorometer to quantify algal periphyton biomass and community composition

    USGS Publications Warehouse

    Harris, Theodore D.; Graham, Jennifer

    2015-01-01

    The bbe-Moldaenke BenthoTorch (BT) is an in vivo fluorometer designed to quantify algal biomass and community composition in benthic environments. The BT quantifies total algal biomass via chlorophyll a (Chl-a) concentration and may differentiate among cyanobacteria, green algae, and diatoms based on pigment fluorescence. To evaluate how BT measurements of periphytic algal biomass (as Chl-a) compared with an ethanol extraction laboratory analysis, we collected BT- and laboratory-measured Chl-a data from 6 stream sites in the Indian Creek basin, Johnson County, Kansas, during August and September 2012. BT-measured Chl-a concentrations were positively related to laboratory-measured concentrations (R2 = 0.47); sites with abundant filamentous algae had weaker relations (R2 = 0.27). Additionally, on a single sample date, we used the BT to determine periphyton biomass and community composition upstream and downstream from 2 wastewater treatment facilities (WWTF) that discharge into Indian Creek. We found that algal biomass increased immediately downstream from the WWTF discharge then slowly decreased as distance from the WWTF increased. Changes in periphyton community structure also occurred; however, there were discrepancies between BT- and laboratory-measured community composition data. Most notably, cyanobacteria were present at all sites based on BT measurements but were present at only one site based on laboratory-analyzed samples. Overall, we found that the BT compared reasonably well with laboratory methods for relative patterns in Chl-a but not as well with absolute Chl-aconcentrations. Future studies need to test the BT over a wider range of Chl-aconcentrations, in colored waters, and across various periphyton assemblages.

  14. New type of dual-channel PAM chlorophyll fluorometer for highly sensitive water toxicity biotests.

    PubMed

    Schreiber, Ulrich; Müller, Jochen F; Haugg, Anke; Gademann, Rolf

    2002-01-01

    A new type of dual-channel PAM chlorophyll fluorometer has been developed, which is specialised in the detection of extremely small differences in photosynthetic activity in algae or thylakoids suspensions. In conjunction with standardised algae cultures or isolated thylakoids, the new device provides an ultrasensitive biotest system for detection of toxic substances in water samples. In this report, major features of the new device are outlined and examples of its performance are presented using suspensions of Phaeodactylum tricornutum (diatoms) and of freeze-dried thylakoids of Lactuca sativa (salad). Investigated and reference samples are exposed to the same actinic intensity of pulse-modulated measuring light. The quantum yields are assessed by the saturation pulse method. Clock-triggered repetitive measurements of quantum yield typically display a standard deviation of 0.1%, corresponding to the inhibition induced by 0.02 mug diuron l(-1). Hence, for diuron or compounds with similar toxicity, the detection limit is well below the 0.1 mug l(-1) defined as the limit for the presence of a single toxic substance in water by the European Commission drinking water regulation. The amounts of water and biotest material required for analysis are very small, as a single assay involves two 1 ml samples, each containing ca. 0.5 mug chlorophyll. Both with Phaeodactylum and thylakoids the relationship between inhibition and diuron concentration is strictly linear up to 10% inhibition, with very similar slopes. Apparent inhibition depends on the actinic effect of the measuring light, showing optima at 6 and 4 mumol quanta m(-2) s(-1) with Phaeodactylum and thylakoids, respectively.

  15. Development of a multi-sensor in situ fiber optic fluorometer. Progress report, June 1, 1992--October 31, 1993

    SciTech Connect

    Lohrenz, S.E.; Asper, V.L.; Morris, M.J.; Walters, R.A.

    1993-11-01

    Our objective is to develop and evaluate a multi-sensor in situ fiber optic fluorometer. The instruments is designed to sample and store in vivo strobe-stimulated fluorescence data at multiple depths and high frequencies (1 Hz). This information may be used for estimating the distribution and abundance of particulate pigment biomass, for supporting models of water column primary production and as a complement to remotely sensed ocean color estimates of pigment biomass. The instrument is unique in that it uses fiber optic technology to increase vertical resolution. While it is theoretically possible to accomplish this task using a large number of commercially available fluorometers, our proposed design would provide a less expensive approach. Two prototype instruments have been built and are being tested. The first, a single sensor instrument interfaced with a 486 personal computer, has been used to optimize hardware and sensor design and to evaluate fiber performance an instrument detection limits. The second instrument, containing 8 sensors and capable of autonomous operation with time-series data acquisition and storage, was recently deployed in a cruise in the Gulf of Mexico. Preliminary results indicate that the instrument meets all the project goals and that low cost, high frequency, high spatial resolution fluorescence data are obtainable with the current design. Additional work will focus on further optimization of hardware design and software algorithms, and construction of an additional instrument specifically designed for deployement in the benthic boundary layer.

  16. Development of a multi-sensor in situ fiber optic fluorometer. Progress report, June 1, 1992--December 31, 1992

    SciTech Connect

    Lohrenz, S.E.; Asper, V.L.; Morris, M.J.; Walters, R.A.

    1992-12-01

    Objective is to develop and evaluate a multi-sensor in situ fiber optic fluorometer. The instrument is designed to sample and store in vivo strobe-stimulated fluorescence data at multiple depths and high frequencies (1 Hz). This information may be used for estimating the distribution and abundance of particulate pigment biomass, for supporting models of water column primary production and as a complement to remotely sensed ocean color estimates of pigment biomass. The instrument is unique in that it uses fiber optic technology to increase vertical resolution. While it is theoretically possible to accomplish this task using a large number of commercially available fluorometers, our proposed design would provide a less expensive approach. A laboratory prototype has been built and is being tested. Preliminary results indicate that the instrument meets all the project goals and that low cost, high frequency, high spatial resolution chlorophyll data are obtainable with the current design. Further work is required to develop the seagoing version, and optimize the configuration of the fiber sensors.

  17. Electrets and plant fluorometers used in field studies to measure hydrogen chloride produced during Space Shuttle launches

    NASA Technical Reports Server (NTRS)

    Milligan, J. E.; Swoboda, G. D.; Susko, M.

    1985-01-01

    The results of the field tests of two monitoring device techniques, electrets and plant fluorometers are analyzed in order to determine the environmental effects of launch by-products and the extent of these effects. The STS launches are used because the Shuttle emits 2 1/2 times more HCl than any previous systems, it produces a voluminous ground cloud and, most important, it produces near field HCl deposition and revolatilization, far-field acid washout/rainout, and gaseous HCl diffusion. Field evaluations of electrets at STS-5, STS-6, and STS-8 have shown that qualitative assessments can be made for areas lightly or moderately impacted by gaseous and aerosol HCl. Field evaluation of the plant productivity fluorometer at STS-8 has shown that this system is also useful for qualitative assessment in areas lightly, moderately, or heavily affected by gaseous and aerosol HCl. Quantitative prediction of HCl may be possible in lightly and moderately affected areas, given deposition rates correlation.

  18. SEEP II, Shelf Edge Exchange Processes-II: Chlorophyll a fluorescence, temperature, and beam attenuation measurements from moored fluorometers

    SciTech Connect

    Medeiros, W.H.; Wirick, C.D.

    1992-02-01

    The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. The first SEEP experiment (SEEP I) was across the outer continental shelf of New England during 1983--1984 and consisted of a series of nine cruises and a mooring array. The second experiment (SEEP II) focused specifically of the shelf/slope frontal region of the mid-Atlantic Bight off the Delmarva peninsula. This report presents data collected during SEEP II. The SEEP II experiment consisted of a series of ten cruises and mooring arrays as well as over-flights by NASA aircraft. The cruises were consecutively designated SEEP2-01 to SEEP2-10. Hydrographic data were collected on all cruises except SEEP2-04 and SEEP2-07 during which benthic processes were investigated. Mooring arrays were deployed during three cruises in the Spring, Summer and Winter of 1988. Brookhaven National Laboratory deployed sixteen fluorometer instrument packages on their moorings with sensors to measure: the in vivo fluorescence of phytoplankton, temperature, subsurface light, dissolved oxygen, and water transparency. Data from the fluorometer, temperature, and transmissometer sensors are reported herein.

  19. SEEP II, Shelf Edge Exchange Processes-II: Chlorophyll a fluorescence, temperature, and beam attenuation measurements from moored fluorometers

    SciTech Connect

    Medeiros, W.H.; Wirick, C.D.

    1992-02-01

    The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. The first SEEP experiment (SEEP I) was across the outer continental shelf of New England during 1983--1984 and consisted of a series of nine cruises and a mooring array. The second experiment (SEEP II) focused specifically of the shelf/slope frontal region of the mid-Atlantic Bight off the Delmarva peninsula. This report presents data collected during SEEP II. The SEEP II experiment consisted of a series of ten cruises and mooring arrays as well as over-flights by NASA aircraft. The cruises were consecutively designated SEEP2-01 to SEEP2-10. Hydrographic data were collected on all cruises except SEEP2-04 and SEEP2-07 during which benthic processes were investigated. Mooring arrays were deployed during three cruises in the Spring, Summer and Winter of 1988. Brookhaven National Laboratory deployed sixteen fluorometer instrument packages on their moorings with sensors to measure: the in vivo fluorescence of phytoplankton, temperature, subsurface light, dissolved oxygen, and water transparency. Data from the fluorometer, temperature, and transmissometer sensors are reported herein.

  20. Electrets and plant fluorometers used in field studies to measure hydrogen chloride produced during Space Shuttle launches

    NASA Technical Reports Server (NTRS)

    Milligan, J. E.; Swoboda, G. D.; Susko, M.

    1985-01-01

    The results of the field tests of two monitoring device techniques, electrets and plant fluorometers are analyzed in order to determine the environmental effects of launch by-products and the extent of these effects. The STS launches are used because the Shuttle emits 2 1/2 times more HCl than any previous systems, it produces a voluminous ground cloud and, most important, it produces near field HCl deposition and revolatilization, far-field acid washout/rainout, and gaseous HCl diffusion. Field evaluations of electrets at STS-5, STS-6, and STS-8 have shown that qualitative assessments can be made for areas lightly or moderately impacted by gaseous and aerosol HCl. Field evaluation of the plant productivity fluorometer at STS-8 has shown that this system is also useful for qualitative assessment in areas lightly, moderately, or heavily affected by gaseous and aerosol HCl. Quantitative prediction of HCl may be possible in lightly and moderately affected areas, given deposition rates correlation.

  1. A phase-shift fluorometer using a laser and a transverse electrooptic modulator for subnanosecond lifetime measurements.

    PubMed Central

    Salmeen, I; Rimai, L

    1977-01-01

    We described a simple phase-shift fluorometer using continuous laser excitation. The laser enables the use of a transverse mode electrooptic modulator with a half-wave retardation voltage of about 200 V (in contrast to many kilovolts of longitudinal modulators) at frequencies up to 100 MHz. The modulated fluorescence signal is detected, after passing through a double monochromator, by a photomultiplier tube feeding a radio frequency (RF) tuned amplifier. THE RF phase is then determined by phase-sensitive detection using a double balanced mixer with the reference obtained from a PIN photodiode-turned amplifier combination which detects light split off from the main exciting beam. The laser and double monochromator allow the observation of modulated Raman solvent and Rayleigh scatterin, which are convenient for determining the zero reference phase. PMID:922124

  2. A fiber optic, ultraviolet light-emitting diode-based, two wavelength fluorometer for monitoring reactive adsorption

    SciTech Connect

    Granz, Christopher D.; Whitten, James E.; Schindler, Bryan J.; Peterson, Gregory W.

    2016-03-15

    Construction and use of an ultraviolet light-emitting diode-based fluorometer for measuring photoluminescence (PL) from powder samples with a fiber optic probe is described. Fluorescence at two wavelengths is detected by miniature photomultiplier tubes, each equipped with a different band pass filter, whose outputs are analyzed by a microprocessor. Photoluminescent metal oxides and hydroxides, and other semiconducting nanoparticles, often undergo changes in their emission spectra upon exposure to reactive gases, and the ratio of the PL intensities at two wavelengths is diagnostic of adsorption. Use of this instrument for reactive gas sensing and gas filtration applications is illustrated by measuring changes in the PL ratio for zirconium hydroxide and zinc oxide particles upon exposure to air containing low concentrations of sulfur dioxide.

  3. A fiber optic, ultraviolet light-emitting diode-based, two wavelength fluorometer for monitoring reactive adsorption.

    PubMed

    Granz, Christopher D; Schindler, Bryan J; Peterson, Gregory W; Whitten, James E

    2016-03-01

    Construction and use of an ultraviolet light-emitting diode-based fluorometer for measuring photoluminescence (PL) from powder samples with a fiber optic probe is described. Fluorescence at two wavelengths is detected by miniature photomultiplier tubes, each equipped with a different band pass filter, whose outputs are analyzed by a microprocessor. Photoluminescent metal oxides and hydroxides, and other semiconducting nanoparticles, often undergo changes in their emission spectra upon exposure to reactive gases, and the ratio of the PL intensities at two wavelengths is diagnostic of adsorption. Use of this instrument for reactive gas sensing and gas filtration applications is illustrated by measuring changes in the PL ratio for zirconium hydroxide and zinc oxide particles upon exposure to air containing low concentrations of sulfur dioxide.

  4. Study of multicomponent mixtures in solution with a vertical-axis transmission-type filter-fluorometer

    USGS Publications Warehouse

    Fletcher, M.H.

    1963-01-01

    Fluorescence intensity, sensitivity, and the effect of diverse ions are discussed in relation to chemical equilibrium and the general equation for fluorescence. High sensitivity is the common denominator in eliminating or reducing all types of interference and the general equation is the key for quickly selecting conditions that give maximum sensitivity. With a transmission-type fluorometer, experimental fluorescence intensities adhere to the general equation over a very wide range of light absorption. If the instrument has a vertical axis, solution depth can be adjusted so that the data fall on that portion of the theoretical curve which is essentially a straight line. When the fluorescence wavelength selected for measurement is not absorbed by the solution, the general equation reduces to a much simpler expression, and then, under proper circumstances, fluorescence values can be used for calculations as confidently and as easily as absorbance values.

  5. A fiber optic, ultraviolet light-emitting diode-based, two wavelength fluorometer for monitoring reactive adsorption

    NASA Astrophysics Data System (ADS)

    Granz, Christopher D.; Schindler, Bryan J.; Peterson, Gregory W.; Whitten, James E.

    2016-03-01

    Construction and use of an ultraviolet light-emitting diode-based fluorometer for measuring photoluminescence (PL) from powder samples with a fiber optic probe is described. Fluorescence at two wavelengths is detected by miniature photomultiplier tubes, each equipped with a different band pass filter, whose outputs are analyzed by a microprocessor. Photoluminescent metal oxides and hydroxides, and other semiconducting nanoparticles, often undergo changes in their emission spectra upon exposure to reactive gases, and the ratio of the PL intensities at two wavelengths is diagnostic of adsorption. Use of this instrument for reactive gas sensing and gas filtration applications is illustrated by measuring changes in the PL ratio for zirconium hydroxide and zinc oxide particles upon exposure to air containing low concentrations of sulfur dioxide.

  6. Intra-leaf gradients of photoinhibition induced by different color lights: implications for the dual mechanisms of photoinhibition and for the application of conventional chlorophyll fluorometers.

    PubMed

    Oguchi, Riichi; Douwstra, Peter; Fujita, Takashi; Chow, Wah Soon; Terashima, Ichiro

    2011-07-01

    • We studied how different color lights cause gradients of photoinhibition within a leaf, to attempt to resolve the controversy of whether photon absorption by chlorophyll or by manganese (Mn) is the primary cause of photoinhibition, as suggested by the excess-energy hypothesis or the two-step hypothesis, respectively. • Lincomycin-treated leaf discs were photoinhibited by white, blue, green or red light. Combining a microfiber fluorometer, a fiber-thinning technique and a micro-manipulator enabled us to measure the chlorophyll fluorescence signals within a leaf. Photoinhibition gradients were also compared with results from various conventional fluorometers to estimate their depth of signal detection. • The severity of photoinhibition was in the descending order of blue, red and green light near the adaxial surface, and in the descending order of blue, green and red light in the deeper tissue, which correlated with the chlorophyll and the Mn absorption spectrums, respectively. These results cannot be explained by either hypothesis alone. • These data strongly suggest that both the excess-energy and the two-step mechanisms occur in photoinhibition, and fluorometers with red or blue measuring light give overestimated or underestimated F(v)/F(m) values of photoinhibited leaves compared with the whole tissue average, respectively; that is, they measured deeper or shallower leaf tissue, respectively.

  7. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

    SciTech Connect

    Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

    2016-06-15

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  8. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters.

    PubMed

    Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

    2016-06-01

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to -0.70 nm within the spectral range of 500-850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  9. Assessment of wavelength-dependent parameters of photosynthetic electron transport with a new type of multi-color PAM chlorophyll fluorometer.

    PubMed

    Schreiber, Ulrich; Klughammer, Christof; Kolbowski, Jörg

    2012-09-01

    Technical features of a novel multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer as well as the applied methodology and some typical examples of its practical application with suspensions of Chlorella vulgaris and Synechocystis PCC 6803 are presented. The multi-color PAM provides six colors of pulse-modulated measuring light (peak-wavelengths at 400, 440, 480, 540, 590, and 625 nm) and six colors of actinic light (AL), peaking at 440, 480, 540, 590, 625 and 420-640 nm (white). The AL can be used for continuous illumination, maximal intensity single-turnover pulses, high intensity multiple-turnover pulses, and saturation pulses. In addition, far-red light (peaking at 725 nm) is provided for preferential excitation of PS I. Analysis of the fast fluorescence rise kinetics in saturating light allows determination of the wavelength- and sample-specific functional absorption cross section of PS II, Sigma(II)(λ), with which the PS II turnover rate at a given incident photosynthetically active radiation (PAR) can be calculated. Sigma(II)(λ) is defined for a quasi-dark reference state, thus differing from σ(PSII) used in limnology and oceanography. Vastly different light response curves for Chlorella are obtained with light of different colors, when the usual PAR-scale is used. Based on Sigma(II)(λ) the PAR, in units of μmol quanta/(m(2) s), can be converted into PAR(II) (in units of PS II effective quanta/s) and a fluorescence-based electron transport rate ETR(II) = PAR(II) · Y(II)/Y(II)(max) can be defined. ETR(II) in contrast to rel.ETR qualifies for quantifying the absolute rate of electron transport in optically thin suspensions of unicellular algae and cyanobacteria. Plots of ETR(II) versus PAR(II) for Chlorella are almost identical using either 440 or 625 nm light. Photoinhibition data are presented suggesting that a lower value of ETR(II)(max) with 440 nm possibly reflects photodamage via absorption by the Mn-cluster of the oxygen

  10. Photolabeling of mitochondrial F1-H+ATPase by 2-azido[3H]ADP and 8-azido[3H]ADP entrapped as fluorometal complexes into the catalytic sites of the enzyme.

    PubMed

    Garin, J; Vinçon, M; Gagnon, J; Vignais, P

    1994-03-29

    In the presence of ADP and fluorometals, the ATPase activity of the catalytic sector, F1, of beef heart mitochondrial ATPase is strongly inhibited; this inhibition is dependent on the entrapment of ADP-fluoroaluminate complexes into the nucleotide binding sites of F1 [Lunardi, J., Dupuis, A., Garin, J., Issartel, J. P., Michel, L., Chabre, M., & Vignais, P. V. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 8958-8962]. We described here the effect of fluoroaluminate on the binding of 2-azido[3H]ADP and 8-azido[3H]ADP to beef heart mitochondrial F1 in the absence and presence of light. When the incubation medium was supplemented with NaF and AlCl3, and maintained in the dark, both 2-azido[3H]ADP and 8-azido[3H]ADP were able to elicit inhibition of F1-ATPase activity, exactly like ADP did. Upon photoirradiation, 2-azido[3H]ADP and 8-azido[3H]ADP bound covalently to F1. Labeling was restricted to the beta subunit of F1, and the same tyrosine residue, beta-Tyr-345, was labeled by either of the photoprobes. This is in contrast with the previous findings that in the absence of fluoroaluminate both the alpha and beta subunits of F1 were photolabeled by 8-azido[3H]ADP, and that two different regions of the beta subunits were labeled, centered on beta-Tyr-345 in the case of 2-azido[3H]ADP [Garin, J., Boulay, F., Issartel, J.P., Lunardi, J., & Vignais, P. V. (1986) Biochemistry 25, 4431-4437] and beta-Tyr-311 that of 8-azido[3H]ADP [Hollemans, M., Runswick, M., Fearnley, I.H., & Walker, J.E. (1983) J. Biol. Chem. 258, 9307-9313].(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Marine Analysis Using a Rapid Scanning Multichannel Fluorometer.

    DTIC Science & Technology

    1985-04-30

    Skeletonema costatum 2 ASP 6 Dinophyceae Amphidinium carterae 3 ASP 6 Cyanophyceae Spirulina major 3 ASP 6 Prymnesiophyceae Prymnesiu parvum 1 ASP 6...of the species except Spirulina major which was kept on the shelf in low light. The medium used was Provasoli’s ASP 6 (21) artificial seawater adjusted...of spectral matching. Hit # Specie A B C Chlorella vulgaris 1 1 1 Dunaliela salina 1 1 1 Tetraselmis sp. 1 1 1 Spirulina major 1 1 1 Skeletonema

  12. Exploring Photosynthesis and Plant Stress Using Inexpensive Chlorophyll Fluorometers

    ERIC Educational Resources Information Center

    Cessna, Stephen; Demmig-Adams, Barbara; Adams, William W., III

    2010-01-01

    Mastering the concept of photosynthesis is of critical importance to learning plant physiology and its applications, but seems to be one of the more challenging concepts in biology. This teaching challenge is no doubt compounded by the complexity by which plants alter photosynthesis in different environments. Here we suggest the use of chlorophyll…

  13. Airborne fluorometer applicable to marine and estuarine studies

    USGS Publications Warehouse

    Stoertz, George E.; Hemphill, William R.; Markle, David A.

    1969-01-01

    An experimental Fraunhofer line discriminator detected solar-stimulated yellow fluorescence (5890 A) emitted by Rhodamine WT dye in aqueous solutions. Concentration of 1 part per billion was detected in tap water 1/2-meter deep. In extremely turbid San Francisco Bay, dye was monitored in concentrations of less than 5 parts per billion from helicopter and ship. Applications include studies of current dynamics and dispersion. Potential applications of the technique could include sensing oil spills, fish oils, lignin sulfonates, other fluorescent pollutants, and chlorophyll fluorescence.

  14. A Portable, Microprocessor Controlled, Multichannel Fluorometer for Marine Analysis.

    DTIC Science & Technology

    1983-01-13

    array. Applied Spectroscopy ,, 36(), 1-18. Udenfriend S. (1962) Molecular Biology: Fluorescence Assay in Biology and Medicine, Vol. 3, pp. 376-377. Vo...and I. M. Warner (1982) Preliminary evaluation of the effects of quenching and inner-filter on the ratio deconvolution of fluorescence data. Applied ... Spectroscopy , 36 (4), 460-466. Govindjee, G. Papageorgiou and E. Rabinowitch (1973) Chlorophyll fluorescence and photosyntesis. In: Practical

  15. Test of airborne fluorometer over land surfaces and geologic materials

    NASA Technical Reports Server (NTRS)

    Stoertz, G. E.; Hemphill, W. R.

    1970-01-01

    Response of an experimental Fraunhofer line discriminator to a wide range of surficial deposits common in deserts and semideserts was tested in the laboratory and from an H-19 helicopter. No signals attributable to fluorescence were recorded during 540 miles of aerial traverses over southeastern California and west-central Arizona. It was concluded that exposed surfaces of target materials throughout the traverses were either nonluminescent at 5890 A or not sufficiently so to be detectable. It cannot be ruled out that the lack of fluorescence is partly attributable to surficial coatings of nonluminescent weathered material. The principal route surveyed from the air was from Needles, California to Furnace Creek Ranch, Death Valley and return, via the Amargosa River valley, Silurian Lake (dry), Silver Lake (dry), and Soda Lake (dry). Principal targets traversed were unconsolidated clastic sediments ranging from silty clay to cobbles, and a wide range of evaporite deposits.

  16. Zooplankton Avoidance of a Profiled Open-Path Fluorometer

    DTIC Science & Technology

    2010-01-01

    studies have demonstrated that dinoflagellate bioluminescence plays a role in trophic dynamics by pro- viding predators (i.e. fishes and cephalopods ...Limnol. Oceanogr., 32, 978–983. Fleisher, K. and Case, J. (1995) Cephalopod predation facilitated by dinoflagellate luminescence. Biol. Bull., 189, 263

  17. Exploring Photosynthesis and Plant Stress Using Inexpensive Chlorophyll Fluorometers

    ERIC Educational Resources Information Center

    Cessna, Stephen; Demmig-Adams, Barbara; Adams, William W., III

    2010-01-01

    Mastering the concept of photosynthesis is of critical importance to learning plant physiology and its applications, but seems to be one of the more challenging concepts in biology. This teaching challenge is no doubt compounded by the complexity by which plants alter photosynthesis in different environments. Here we suggest the use of chlorophyll…

  18. Feasibility of surveying pesticide coverage with airborne fluorometer

    NASA Technical Reports Server (NTRS)

    Stoertz, G. E.; Hemphill, W. R.

    1970-01-01

    Response of a Fraunhofer line discriminator (FLD) to varying distributions of granulated corncobs stained with varying concentrations of Rhodamine WT dye was tested on the ground and from an H-19 helicopter. The granules are used as a vehicle for airborne emplacement of poison to control fire ants in the eastern and southeastern United States. Test results showed that the granules are detectable by FLD but that the concentration must be too great to be practical with the present apparatus. Possible methods for enhancement of response may include: (1) increasing dye concentration; (2) incorporating with the poisoned granules a second material to carry the dye alone; (3) use of a more strongly fluorescent substance (at 5890 A); (4) modifying the time interval after dyeing, or modifying the method of dyeing; (5) modifying the FLD for greater efficiency, increased field of view or larger optics; or (6) experimenting with laser-stimulated fluorescence.

  19. An LED-based fluorometer for chlorophyll quantification in the laboratory and in the field.

    PubMed

    Lamb, Jacob J; Eaton-Rye, Julian J; Hohmann-Marriott, Martin F

    2012-10-01

    The chlorophyll content is an important experimental parameter in agronomy and plant biology research. In this report, we explore the feasibility of determining total concentration of extracts containing chlorophyll a and chlorophyll b by chlorophyll fluorescence. We found that an excitation at 457 nm results in the same integrated fluorescence emission for a molecule of chlorophyll a and a molecule of chlorophyll b. The fluorescence yield induced by 457 nm is therefore proportional to total molar chlorophyll concentration. Based on this observation, we designed an instrument to determine total chlorophyll concentrations. A single light emitting diode (LED) is used to excite chlorophyll extracts. After passing through a long-pass filter, the fluorescence emission is assessed by a photodiode. We demonstrate that this instrument facilitates the determination of total chlorophyll concentrations. We further extended the functionality of the instrument by including LEDs emitting at 435 and 470 nm wavelengths, thereby preferentially exciting chlorophyll a and chlorophyll b. This instrument can be used to determine chlorophyll a and chlorophyll b concentrations in a variety of organisms containing different ratios of chlorophylls. Monte-Carlo simulations are in agreement with experimental data such that a precise determination of chlorophyll concentrations in carotenoid-containing biological samples containing a concentration of less than 5 nmol/mL total chlorophyll can be achieved.

  20. Ratiometric Ca²+ measurements using the FlexStation® Scanning Fluorometer.

    PubMed

    Marshall, Ian C B; Boyfield, Izzy; McNulty, Shaun

    2005-01-01

    Many commercial organizations currently use the Fluorometric Imaging Plate Reader (FLIPR®: Molecular Devices, Sunnyvale, CA) to conduct high-throughput measurements of intracellular Ca(2+) concentration (see Chapter 7 ), taking advantage of its rapid kinetics, reliability, and compatibility for automation. For the majority of industrial applications, the primary limitation of FLIPR (i.e., its requirement for single wavelength fluorescent probes using visible light excitation) is not a significant issue. Indeed, visible light probes offer certain benefits over their ultraviolet (UV)-excited ratiometric counterparts, such as reduced sample autofluorescence and higher absorbance, thereby allowing relatively low concentrations of dye to be used. However, under certain circumstances researchers may prefer to conduct high-throughput experiments with ratiometric dyes, particularly when issues of dye leakage, photobleaching, or signal-to-noise ratio become a concern.

  1. Two-wavelength, multipurpose, truly portable chlorophyll fluorometer and its application in field monitoring of phytoremediation

    NASA Astrophysics Data System (ADS)

    Barócsi, A.; Kocsányi, L.; Várkonyi, S.; Richter, P.; Csintalan, Z.; Szente, K.

    2000-06-01

    In this paper a compact, portable instrument is presented for the measurement of full chlorophyll fluorescence kinetics of plants at two different wavelengths. The instrument uses a 635 nm laser diode as a light source with variable gain driving that allows excitations at selectable actinic levels. The plant fluorescence is detected, at 690 nm and 735 nm, through a specially mixed three-branch optical fibre bundle. Large scale field monitoring of vegetation is made possible by the utilization of PC/104-form embedded electronics including a low power, IBM PC/386-compatible single board computer (SBC) with non-volatile flash memory. Application of a general purpose SBC and task oriented programming offers in situ data evaluation making process control possible. The capabilities of the instrument were demonstrated in monitoring soil phytoremediation processes.

  2. Confocal fluorometer for diffusion tracking in 3D engineered tissue constructs

    NASA Astrophysics Data System (ADS)

    Daly, D.; Zilioli, A.; Tan, N.; Buttenschoen, K.; Chikkanna, B.; Reynolds, J.; Marsden, B.; Hughes, C.

    2016-03-01

    We present results of the development of a non-contacting instrument, called fScan, based on scanning confocal fluorometry for assessing the diffusion of materials through a tissue matrix. There are many areas in healthcare diagnostics and screening where it is now widely accepted that the need for new quantitative monitoring technologies is a major pinch point in patient diagnostics and in vitro testing. With the increasing need to interpret 3D responses this commonly involves the need to track the diffusion of compounds, pharma-active species and cells through a 3D matrix of tissue. Methods are available but to support the advances that are currently only promised, this monitoring needs to be real-time, non-invasive, and economical. At the moment commercial meters tend to be invasive and usually require a sample of the medium to be removed and processed prior to testing. This methodology clearly has a number of significant disadvantages. fScan combines a fiber based optical arrangement with a compact, free space optical front end that has been integrated so that the sample's diffusion can be measured without interference. This architecture is particularly important due to the "wet" nature of the samples. fScan is designed to measure constructs located within standard well plates and a 2-D motion stage locates the required sample with respect to the measurement system. Results are presented that show how the meter has been used to evaluate movements of samples through collagen constructs in situ without disturbing their kinetic characteristics. These kinetics were little understood prior to these measurements.

  3. A remote sensing laser fluorometer. [for detecting oil, ligninsulfonates, and chlorophyll in water

    NASA Technical Reports Server (NTRS)

    Oneill, R. A.; Davis, A. R.; Gross, H. G.; Kruus, J.

    1975-01-01

    A sensor is reported which is able to identify certain specific substances in water by means of their fluorescence spectra. In particular, the sensor detects oil, ligninsulfonates and chlorophyll. The device is able to measure the fluorescence spectra of water at ranges up to 75 m and to detect oil spills on water at altitudes up to 300 m. Blue light from a laser is used to excite the fluorescence of the target. Any light from the ambient background illumination, from the reflected laser light or from the induced fluorescence is gathered by a small telescope focused on the target. Optical filters are used to block the reflected laser light and to select the wavelengths of interest in the fluorescence spectrum of the target. The remaining light is detected with a photomultiplier tube. The amplitude of the laser induced fluorescence in the wavelength interval selected by the optical filters is displayed on a meter or strip chart recorder.

  4. Evaluation of the Stratus CS fluorometer for the determination of plasma myoglobin.

    PubMed

    Couck, P; Claeys, R; Vanderstraeten, E; Gorus, F K

    2005-01-01

    Circulating myoglobin is recognized as an early and sensitive marker of acute coronary diseases. Long turnaround time of myoglobin assays jeopardize their clinical utility. We evaluated the analytical performance of the Stratus CS fluorometric enzyme immunoassay based on dendrimer technology, and claimed to achieve a fast and reliable determination of plasma myoglobin concentrations. Precision complied with the recommended analytical performance criteria. Method comparison and recovery experiments indicated, that despite good between-method correlations, the Stratus CS method overestimated myoglobin concentrations in comparison with values obtained on Cobas Integra 400 and BN A. However, since the manufacturers' cut-off for elevated plasma myoglobin levels was higher for Stratus CS than for other techniques, few discrepant results were observed between methods. Elevated levels of hemoglobin, triglycerides and rheumatoid factors did not interfere in the Stratus CS method but hyperbilirubinemia caused a positive difference.

  5. A remote sensing laser fluorometer. [for detecting oil, ligninsulfonates, and chlorophyll in water

    NASA Technical Reports Server (NTRS)

    Oneill, R. A.; Davis, A. R.; Gross, H. G.; Kruus, J.

    1975-01-01

    A sensor is reported which is able to identify certain specific substances in water by means of their fluorescence spectra. In particular, the sensor detects oil, ligninsulfonates and chlorophyll. The device is able to measure the fluorescence spectra of water at ranges up to 75 m and to detect oil spills on water at altitudes up to 300 m. Blue light from a laser is used to excite the fluorescence of the target. Any light from the ambient background illumination, from the reflected laser light or from the induced fluorescence is gathered by a small telescope focused on the target. Optical filters are used to block the reflected laser light and to select the wavelengths of interest in the fluorescence spectrum of the target. The remaining light is detected with a photomultiplier tube. The amplitude of the laser induced fluorescence in the wavelength interval selected by the optical filters is displayed on a meter or strip chart recorder.

  6. A portable fluorometer for the rapid screening of M1 aflatoxin in milk

    NASA Astrophysics Data System (ADS)

    Cucci, C.; Mignani, A. G.; Dall'Asta, C.; Galaverna, G.; Dossena, A.; Marchelli, R.; Pela, R.

    2006-04-01

    A compact fluorometric sensor equipped with a LED source and a high sensitivity PMT detector has been implemented for the selective detection of native fluorescence of aflatoxin AFM1 in liquid solutions. This compact and easy-to-handle device is addressed to the rapid monitoring of AFM1 in milk, enabling the detection of concentrations up to the legal limit, which is 50 ppt. The system is suitable for preliminary screening at the earlier stages of the industrial process, and makes it possible to discard contaminated milk stocks before their inclusion in the production chain.

  7. Simulation analysis of moored fluorometer time series from the Mid-Atlantic Bight during 1987--1990

    SciTech Connect

    Walsh, J.J.

    1990-01-01

    The goal of the previous research during 1987-1990 within the DOE (Department of Energy) Shelf Edge Exchange Processes (SEEP) program in the Mid-Atlantic Bight was to understand the physical and biogeochemical processes effecting the diffusive exchange of the proxies of energy-related, by-products associated with particulate matter between estuarine, shelf, and slope waters on this continental margin. As originally envisioned in the SEEP program plan, SEEP-III would take place at Cape Hatteras to study the advective exchange of materials by a major boundary current. One problem of continuing interest is the determination of the local assimilative capacity of slope waters and sediments off the eastern seaboard of the US to lengthen the pathway between potentially harmful energy by-products and man. At basin scales, realistic specification of the lateral transport by western boundary currents of particulate matter is a necessary input to global models of carbon/nitrogen cycling. Finally, at these global scales, the generic role of continental margins in cycling greenhouse gases, e.g. CO{sub 2}, CH{sub 4}, and N{sub 2}O, is now of equal interest. This continuing research of model construction and evaluation within the SEEP program focuses on all three questions at local, regional, and basin scales. Results from SEEP-I and II are discussed as well as plans for SEEP-III. 14 figs., 3 tabs.

  8. Design and development of a rapid acquisition laser-based fluorometer with simultaneous spectral and temporal resolution

    NASA Astrophysics Data System (ADS)

    Pitts, Jonathan D.; Mycek, Mary-Ann

    2001-07-01

    We report the design, development, and characterization of a sensitive, time-resolved fluorescence spectrometer capable of measuring fluorescence spectra and transient decays simultaneously, with data acquisition times less than 1 s. The spectrometer, a portable fluorescence lifetime spectrometer (FLS), was designed to be compatible with both laboratory and clinical research studies on biological systems, and was applied to the study of several biological fluorophores in vitro and human tissue in vivo. The instrument consisted of a nitrogen laser pumping a dye laser for excitation from 337.1 nm through the near infrared, a quartz fiber-optic probe for remote light delivery and collection, and amplified detectors for rapid spectral and temporal detection from 350 to 800 nm. The spectral resolution of the FLS was determined to be 3 nm, which is sufficient for accurately detecting the broad spectral bands associated with biological fluorophores. The FLS was able to detect 5×10-7 M fluorescein dye concentrations with spectral signal-to-noise ratios (SNRs) of 29. Time-resolved detection with the FLS had a dynamic range of approximately three decades with a SNR of 200. Using fluorescence lifetime standards, the FLS was determined to be capable of accurately resolving fluorophore lifetimes from hundreds of picoseconds to tens of nanoseconds in duration, with an ultimate temporal resolution of 360 ps.

  9. Rapid Processing of Turner Designs Model 10-Au-005 Internally Logged Fluorescence Data

    EPA Science Inventory

    Continuous recording of dye fluorescence using field fluorometers at selected sampling sites facilitates acquisition of real-time dye tracing data. The Turner Designs Model 10-AU-005 field fluorometer allows for frequent fluorescence readings, data logging, and easy downloading t...

  10. Rapid Processing of Turner Designs Model 10-Au-005 Internally Logged Fluorescence Data

    EPA Science Inventory

    Continuous recording of dye fluorescence using field fluorometers at selected sampling sites facilitates acquisition of real-time dye tracing data. The Turner Designs Model 10-AU-005 field fluorometer allows for frequent fluorescence readings, data logging, and easy downloading t...

  11. Ultraviolet fluorescence monitor

    SciTech Connect

    Hargis, P.J. Jr.; Preppernau, B.L.; Aragon, B.P.

    1997-05-01

    A multispectral ultraviolet (UV) fluorescence imaging fluorometer and a pulsed molecular beam laser fluorometer were developed to detect volatile organic compounds of interest in environmental monitoring and drug interdiction applications. The UV fluorescence imaging fluorometer is a relatively simple instrument which uses multiple excitation wavelengths to measure the excitation/emission matrix for irradiated samples. Detection limits in the high part-per-million to low part-per-million range were measured for a number of volatile organic vapors in the atmosphere. Detection limits in the low part-per-million range were obtained using cryogenic cooling to pre-concentrate unknown samples before introducing them into the imaging fluorometer. A multivariate analysis algorithm was developed to analyze the excitation/emission matrix and used to determine the relative concentrations of species in computer synthesized mixtures containing up to five organic compounds. Analysis results demonstrated the utility of multispectral UV fluorescence in analytical measurements. A transportable UV fluorescence imaging fluorometer was used in two field tests. Field test results demonstrated that detection limits in the part-per-billion range were needed to reliably identify volatile organic compounds in realistic field test measurements. The molecular beam laser fluorometer, a more complex instrument with detection limits in the part-per-billion to part-per-trillion range, was therefore developed to satisfy detection sensitivity requirements for field test measurements. High-resolution spectroscopic measurements made with the molecular beam laser fluorometer demonstrated its utility in identifying volatile organic compounds in the atmosphere.

  12. A 5-kg time-resolved luminescence photometer with multiple excitation sources

    USDA-ARS?s Scientific Manuscript database

    A portable fluorometer was developed to detect food contaminants and environmental pollutants including, in particular, two classes of antibiotics: tetracyclines and fluoroquinolones. Time resolution was implemented to take advantage of lanthanide-sensitized luminescence. Excitation sources included...

  13. Assessment of a portable device to quantify vitamin A in fortified foods (flour, sugar, and milk) for quality control.

    PubMed

    Laillou, Arnaud; Renaud, Cécile; Berger, Jacques; Moench-Pfanner, Regina; Fontan, Laura; Avallone, Sylvie

    2014-12-01

    Simple-to-use quantitative methods are needed to check the adequacy of vitamin A fortification levels. To assess the capacity of a portable fluorometer (iCheck FLUORO) and its test kit vials (iEx Mila) to quantify retinyl palmitate in fortified milks, flours (wheat, maize), and sugar. The portable fluorometer was assessed in a three-step procedure to determine its working range and linearity, intra-assay precision, and interperson precision. Measurements were compared with the results obtained by high-performance liquid chromatography (HPLC), commonly regarded as the standard method for vitamin A analysis. The portable fluorometer (iCheck FLUORO) and its test kit vials (iEx Mila) precisely determined the vitamin A contents in fortifed flours, sugar, and milks. Its working range was 1 to 10, 0.5 to 3.0, and 5 to 15 mg retinol equivalents (RE) kg(-1) for flours (wheat and corn), milks, and sugar, respectively; these values are in accordance with the World Health Organization recommendations for food fortification in least developed countries. The limits of detection are higher than those of HPLC but are all satisfactory (< 1.46 mg RE kg(-1)). The coefficients of variation within and between observers were satisfactory, especially for sugar and milk. The linear relationship between the data from the portable fluorometer and the HPLC data confirms that the portable fluorometer provides a good determination of the vitamin A content of the fortified products in the tested range.

  14. In situ measurements of phytoplankton fluorescence using low cost electronics.

    PubMed

    Leeuw, Thomas; Boss, Emmanuel S; Wright, Dana L

    2013-06-19

    Chlorophyll a fluorometry has long been used as a method to study phytoplankton in the ocean. In situ fluorometry is used frequently in oceanography to provide depth-resolved estimates of phytoplankton biomass. However, the high price of commercially manufactured in situ fluorometers has made them unavailable to some individuals and institutions. Presented here is an investigation into building an in situ fluorometer using low cost electronics. The goal was to construct an easily reproducible in situ fluorometer from simple and widely available electronic components. The simplicity and modest cost of the sensor makes it valuable to students and professionals alike. Open source sharing of architecture and software will allow students to reconstruct and customize the sensor on a small budget. Research applications that require numerous in situ fluorometers or expendable fluorometers can also benefit from this study. The sensor costs US$150.00 and can be constructed with little to no previous experience. The sensor uses a blue LED to excite chlorophyll a and measures fluorescence using a silicon photodiode. The sensor is controlled by an Arduino microcontroller that also serves as a data logger.

  15. In situ Measurements of Phytoplankton Fluorescence Using Low Cost Electronics

    PubMed Central

    Leeuw, Thomas; Boss, Emmanuel S.; Wright, Dana L.

    2013-01-01

    Chlorophyll a fluorometry has long been used as a method to study phytoplankton in the ocean. In situ fluorometry is used frequently in oceanography to provide depth-resolved estimates of phytoplankton biomass. However, the high price of commercially manufactured in situ fluorometers has made them unavailable to some individuals and institutions. Presented here is an investigation into building an in situ fluorometer using low cost electronics. The goal was to construct an easily reproducible in situ fluorometer from simple and widely available electronic components. The simplicity and modest cost of the sensor makes it valuable to students and professionals alike. Open source sharing of architecture and software will allow students to reconstruct and customize the sensor on a small budget. Research applications that require numerous in situ fluorometers or expendable fluorometers can also benefit from this study. The sensor costs US$150.00 and can be constructed with little to no previous experience. The sensor uses a blue LED to excite chlorophyll a and measures fluorescence using a silicon photodiode. The sensor is controlled by an Arduino microcontroller that also serves as a data logger. PMID:23783738

  16. Tissue-based water quality biosensors for detecting chemical warfare agents

    DOEpatents

    Greenbaum, Elias; Sanders, Charlene A.

    2003-05-27

    A water quality sensor for detecting the presence of at least one chemical or biological warfare agent includes: a cell; apparatus for introducing water into the cell and discharging water from the cell adapted for analyzing photosynthetic activity of naturally occurring, free-living, indigenous photosynthetic organisms in water; a fluorometer for measuring photosynthetic activity of naturally occurring, free-living, indigenous photosynthetic organisms drawn into the cell; and an electronics package that analyzes raw data from the fluorometer and emits a signal indicating the presence of at least one chemical or biological warfare agent in the water.

  17. Modulated Chlorophyll "a" Fluorescence: A Tool for Teaching Photosynthesis

    ERIC Educational Resources Information Center

    Marques da Silva, Jorge; Bernardes da Silva, Anabela; Padua, Mario

    2007-01-01

    "In vivo" chlorophyll "a" fluorescence is a key technique in photosynthesis research. The recent release of a low cost, commercial, modulated fluorometer enables this powerful technology to be used in education. Modulated chlorophyll a fluorescence measurement "in vivo" is here proposed as a tool to demonstrate basic…

  18. "Open-Box" Approach to Measuring Fluorescence Quenching Using an iPad Screen and Digital SLR Camera

    ERIC Educational Resources Information Center

    Koenig, Michael H.; Yi, Eun P.; Sandridge, Matthew J.; Mathew, Alexander S.; Demas, James N.

    2015-01-01

    Fluorescence quenching is an analytical technique and a common undergraduate laboratory exercise. Unfortunately, a typical quenching experiment requires the use of an expensive fluorometer that measures the relative fluorescence intensity of a single sample in a closed compartment unseen by the experimenter. To overcome these shortcomings, we…

  19. Detection of Oil in Water Column, Final Report: Detection Prototype Tests

    DTIC Science & Technology

    2014-07-01

    is 1 Hz. Accessory ports are available for additional sensors such as oil-in- water fluorometers. A robust deck controller unit in a waterproof ...was to design and fabricate an oil delivery system capable of providing varying pressures and flows to orifice nozzles underwater. The LISST 100X

  20. Multiparameter Fluorescence Methods for Analysis in the Marine Environment

    DTIC Science & Technology

    1988-01-01

    Multichannel Fluorometer," NATO Advanced Study Institute on Advanced Techniques on Marine Pollution Studies, Beaulieu-Sur- Mer, France, October 4-14, 1984...Techniques on Marine Pollution Studies, Beaulieu-Sur-Mer, France, October 1-14, 1984. 4) Warner, I.M., Patonay, G. and Thomas, M., "Multidimensional

  1. Smart oxygen cuvette for optical monitoring of dissolved oxygen in biological blood samples

    NASA Astrophysics Data System (ADS)

    Dabhi, Harish; Alla, Suresh Kumar; Shahriari, Mahmoud R.

    2010-02-01

    A smart Oxygen Cuvette is developed by coating the inner surface of a cuvette with oxygen sensitive thin film material. The coating is glass like sol-gel based sensor that has an embedded ruthenium compound in the glass film. The fluorescence of the ruthenium is quenched depending on the oxygen level. Ocean Optics phase fluorometer, NeoFox is used to measure this rate of fluorescence quenching and computes it for the amount of oxygen present. Multimode optical fibers are used for transportation of light from an LED source to cuvette and from cuvette to phase fluorometer. This new oxygen sensing system yields an inexpensive solution for monitoring the dissolved oxygen in samples for biological and medical applications. In addition to desktop fluorometers, smart oxygen cuvettes can be used with the Ocean Optics handheld Fluorometers, NeoFox Sport. The Smart Oxygen Cuvettes provide a resolution of 4PPB units, an accuracy of less than 5% of the reading, and 90% response in less than 10 seconds.

  2. Atlantic coastal experiment 5: R/V advance II cruise (MESEX I) 27 April--2 May 1979, data report

    SciTech Connect

    von Bock, K.

    1983-03-01

    68 hydrographic stations were arranged as boundary transects, and a proximate calibration matrix, to an array of current meters and fluorometers moored within the coastal boundary layer near southern Long Island. Assessments were made of water-mass characterization, nutrient distribution, chlorophyll variability and phytoplankton composition. Supplemental thermal structure was obtained from expendable bathythermographs.

  3. Optical Constituents Along a River Mouth and Inlet: Variability and Signature in Remotely Sensed Reflectance

    DTIC Science & Technology

    2012-09-30

    Floc Camera ( DFC ), and RBR CTD. The second comprised a WETLabs ac-s, BB-9, a CDOM fluorometer and a Seabird CTD (IOP package) and was used to...the LISST and DFC following the protocols developed in the OASIS project (Hill et al., 2011). Mass normalized backscattering and absorption of

  4. Optical Constituents Along a River Mouth and Inlet: Variability and Signature in Remotely Sensed Reflectance

    DTIC Science & Technology

    2013-09-30

    Digital Floc Camera ( DFC ), and RBR CTD. The second comprised a WETLabs ac-s, BB-9, a CDOM fluorometer Report Documentation Page Form ApprovedOMB No...LISST and DFC following the protocols developed in the OASIS project (Hill et al., 2011). Mass normalized backscattering and absorption of particles

  5. Fluorescence Spectroscopy in a Shoebox

    ERIC Educational Resources Information Center

    Wahab, M. Farooq

    2007-01-01

    The construction of a fluorometer and a spectrofluorometer using flashlight or a sunlight excitation source in a shoebox and the eye as a detector is being described. The assembly helps in understanding several fundamental ideas related to the subject very easily.

  6. Modulated Chlorophyll "a" Fluorescence: A Tool for Teaching Photosynthesis

    ERIC Educational Resources Information Center

    Marques da Silva, Jorge; Bernardes da Silva, Anabela; Padua, Mario

    2007-01-01

    "In vivo" chlorophyll "a" fluorescence is a key technique in photosynthesis research. The recent release of a low cost, commercial, modulated fluorometer enables this powerful technology to be used in education. Modulated chlorophyll a fluorescence measurement "in vivo" is here proposed as a tool to demonstrate basic…

  7. Fluorometry as a bacterial source tracking tool in coastal watersheds, Trinidad, CA

    Treesearch

    Trever Parker; Andrew Stubblefield

    2012-01-01

    Bacterial counts have long been used as indicators of water pollution that may affect public health. By themselves, bacteria are indicators only and can not be used to identify the source of the pollutant for remediation efforts. Methods of microbial source tracking are generally time consuming, labor intensive and expensive. As an alternative, a fluorometer can be...

  8. Fluorescence Spectroscopy in a Shoebox

    ERIC Educational Resources Information Center

    Wahab, M. Farooq

    2007-01-01

    The construction of a fluorometer and a spectrofluorometer using flashlight or a sunlight excitation source in a shoebox and the eye as a detector is being described. The assembly helps in understanding several fundamental ideas related to the subject very easily.

  9. "Open-Box" Approach to Measuring Fluorescence Quenching Using an iPad Screen and Digital SLR Camera

    ERIC Educational Resources Information Center

    Koenig, Michael H.; Yi, Eun P.; Sandridge, Matthew J.; Mathew, Alexander S.; Demas, James N.

    2015-01-01

    Fluorescence quenching is an analytical technique and a common undergraduate laboratory exercise. Unfortunately, a typical quenching experiment requires the use of an expensive fluorometer that measures the relative fluorescence intensity of a single sample in a closed compartment unseen by the experimenter. To overcome these shortcomings, we…

  10. Water Quality and Plankton in the United States Nearshore Waters of Lake Huron

    EPA Science Inventory

    We conducted an intensive survey for the US nearshore of Lake Huron along a continuous segment (523 km) from Port Huron Michigan to Detour Passage. A depth contour of 20 m was towed with a CTD, fluorometer, transmissometer, and laser optical plankton counter (LOPC). The continu...

  11. 40 CFR 53.59 - Aerosol transport test for Class I equivalent method samplers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... with 0.01 N NaOH and then dried. (2) Generate aerosol. (i) Generate aerosol composed of oleic acid with... fluorometer. Record the mass of fluorometric material on each no-flow filter as Mno-flow. (7) Using 0.01 N Na...

  12. 40 CFR 53.59 - Aerosol transport test for Class I equivalent method samplers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with 0.01 N NaOH and then dried. (2) Generate aerosol. (i) Generate aerosol composed of oleic acid with... fluorometer. Record the mass of fluorometric material on each no-flow filter as Mno-flow. (7) Using 0.01 N Na...

  13. Water Quality and Plankton in the United States Nearshore Waters of Lake Huron

    EPA Science Inventory

    We conducted an intensive survey for the US nearshore of Lake Huron along a continuous segment (523 km) from Port Huron Michigan to Detour Passage. A depth contour of 20 m was towed with a CTD, fluorometer, transmissometer, and laser optical plankton counter (LOPC). The continu...

  14. Autofluorescence And Other Optical Properties As Tools In Biological Oceanography

    NASA Astrophysics Data System (ADS)

    Cullen, John J.; Yentsch, Clarice M.; Cucci, Terry L.; MacIntyre, Hugh L.

    1988-08-01

    Bulk fluorescence measurements have been popular in algal culture studies and in oceanographic and limnological applications. Usually, fluorescence is interpreted as an indicator of chlorophyll concentration or phytoplankton biomass, but sometimes measurements of fluorescence can be related to physiological properties of phytoplankton, such as responses to light. Now that in situ fluorometers are being deployed routinely with optical packages, there is active interest in interpreting the relationships between fluorescence, beam transmission, diffuse attenuation, and the physiological characteristics of phytoplankton. Flow cytometry offers the potential to extend these interpretations to the scale of individual cells. It may be difficult to compare measurements of fluorescence, however, because instruments differ greatly in excitation irradiance and time scale of measurement. With this in mind, we examined the short-term responses of a marine diatom to bright light, comparing different instruments (SeaTech in situ fluorometer, Turner Designs fluorometer, EPICS flow cytometer, FACS Analyzer, SeaTech beam transmissometer) while making concurrent measurements of photosynthesis vs irradiance and absorption spectra. Each fluorometer yielded somewhat different information, yet all showed a similar pattern of inhibition after exposure. One instrument, the in situ pulsed fluorometer, could show rapid changes of fluorescence immediately after large shifts of irradiance. Beam attenuation did not decline with the bright light treatment, nor did the specific absorption of chlorophyll. Photosynthetic efficiency was reduced after exposure to bright light, but the capacity for photosynthesis in high irradiance increased at the same time. These results are preliminary: nonetheless they support some interpretations of fluorescence/beam attenuation ratios, clarify some aspects of photosynthetic response to bright light, and suggest that flow cytometry may be useful for assessing

  15. Validation of Ferrybox Observations and Comparison between Ferrybox Ferries

    NASA Astrophysics Data System (ADS)

    Kaitala, Seppo; Seppälä, Jukka; Maunula, Petri; Kallio, Kari Y.; Ruohola, Jani

    2016-04-01

    The annual Alg@line ferrybox instrument calibration is carried out annually in January in Finnish Environment institute (SYKE). The chlorophyll and phycocyanin fluorometers are calibrated with algae cultures. All sensors are compared also with each other. Fluorometer readings are validated against water sample analysis in laboratory biweekly during the year. This validation step using water samples is necessary due to different optical properties of phytoplankton species. When calibration and validation are carried out with similar protocols, there is a possibility to compare the ferrybox observations in the same area by different ferries. The Ferryboxes operating in the Central Baltic occasionally occur in the same area within the 24 hours. Spatiotemporal comparisons of chlorophyll fluorescence, temperature and salinity observations are demonstrated.

  16. Fluorometric procedures for dye tracing

    USGS Publications Warehouse

    Wilson, James F.

    1968-01-01

    This manual describes the current fluorometric procedures used by the U.S. Geological Survey in dye tracer studies such as time of travel, dispersion, reaeration, and dilution-type discharge measurements. The advantages of dye tracing are (1) low detection and measurement limits and (2) simplicity and accuracy in measuring dye tracer concentrations using fluorometric techniques. The manual contains necessary background information about fluorescence, dyes, and fluorometers and a description of fluorometric operation and calibration procedures as a guide for laboratory and field use. The background information should be useful to anyone wishing to experiment with dyes, fluorometer components, or procedures different from those described. In addition, a brief section on aerial photography is included because of its possible use to supplement ground-level fluorometry.

  17. Fluorometric procedures for dye tracing

    USGS Publications Warehouse

    Wilson, James E.; Cobb, E.D.; Kilpatrick, F.A.

    1984-01-01

    This manual describes the current fluorometric procedures used by the U.S. Geological Survey in dye tracer studies such as time of travel, dispersion, reaeration, and dilution-type discharge measurements. The outstanding characteristics of dye tracing are: (1) the low detection and measurement limits, and (2) the simplicity and accuracy of measuring dye tracer concentrations using fluorometric techniques. The manual contains necessary background information about fluorescence, dyes, and fluorometers and a description of fluorometric operation and calibration procedures as a general guide for laboratory and field use. The background information should be useful to anyone wishing to experiment with dyes, fluorometer components, or procedures different from those described. In addition, a brief section is included on aerial photography because of its possible use to supplement ground-level fluorometry. (USGS)

  18. Fluorometric procedures for dye tracing

    USGS Publications Warehouse

    Wilson, James F.; Cobb, Ernest D.; Kilpatrick, F.A.

    1986-01-01

    This manual describes the current fluorometric procedures used by the U.S. Geological Survey in dye tracer studies such as time of travel, dispersion, reaeration, and dilution-type discharge measurements. The advantages of dye tracing are (1) low detection and measurement limits and (2) simplicity and accuracy in measuring dye tracer concentrations using fluorometric techniques. The manual contains necessary background information about fluorescence, dyes, and fluorometers and a description of fluorometric operation and calibration procedures as a guide for laboratory and field use. The background information should be useful to anyone wishing to experiment with dyes, fluorometer components, or procedures different from those described. In addition, a brief section on aerial photography is included because of its possible use to supplement ground-level fluorometry.

  19. Fluorometric procedures for dye tracing

    USGS Publications Warehouse

    Wilson, James E.; Cobb, Ernest D.; Kilpatrick, Frederick A.

    1984-01-01

    This manual describes the current fluorometric procedures used by the U.S. Geological Survey in dye tracer studies such as time of travel, dispersion, reaeration, and dilution-type discharge measurements. The outstanding characteristics of dye tracing are: (1) the low detection and measurement limits, and (2) the simplicity and accuracy of measuring dye tracer concentrations using fluorometric techniques. The manual contains necessary background information about fluorescence, dyes, and fluorometers and a description of fluorometric operation and calibration procedures as a general guide for laboratory and field use. The background information should be useful to anyone wishing to experiment with dyes, fluorometer components, or procedures different from those described. In addition, a brief section is included on aerial photography because of its possible use to supplement ground-level fluorometry.

  20. Measuring indigenous photosynthetic organisms to detect chemical warefare agents in water

    DOEpatents

    Greenbaum, Elias; Sanders, Charlene A.

    2005-11-15

    A method of testing water to detect the presence of a chemical or biological warfare agent is disclosed. The method is carried out by establishing control data by providing control water containing indigenous organisms but substantially free of a chemical and a biological warfare agent. Then measuring photosynthetic activity of the control water with a fluorometer to obtain control data to compare with test data to detect the presence of the chemical or agent. The test data is gathered by providing test water comprising the same indigenous organisms as contained in the control water. Further, the test water is suspected of containing the chemical or agent to be tested for. Photosynthetic activity is also measured by fluorescence induction in the test water using a fluorometer.

  1. Tissue-based standoff biosensors for detecting chemical warfare agents

    DOEpatents

    Greenbaum, Elias; Sanders, Charlene A.

    2003-11-18

    A tissue-based, deployable, standoff air quality sensor for detecting the presence of at least one chemical or biological warfare agent, includes: a cell containing entrapped photosynthetic tissue, the cell adapted for analyzing photosynthetic activity of the entrapped photosynthetic tissue; means for introducing an air sample into the cell and contacting the air sample with the entrapped photosynthetic tissue; a fluorometer in operable relationship with the cell for measuring photosynthetic activity of the entrapped photosynthetic tissue; and transmitting means for transmitting analytical data generated by the fluorometer relating to the presence of at least one chemical or biological warfare agent in the air sample, the sensor adapted for deployment into a selected area.

  2. LIDAR Studies of Small-Scale Lateral Dispersion in the Ocean

    DTIC Science & Technology

    2010-09-30

    field test / pilot cruise performed in August, 2010 in the Sargasso Sea , southeast of Cape Hatteras (Fig 1). Cruise participants included the WHOI and...absorption/attenuation sensor, a Sea Sciences Acrobat tow sled, and a new micro CTD and fluorometer sampling package for small-scale surveys of the dye...density fronts (Fig. 1). The sites for these releases were chosen on the basis of satellite images of sea surface height and temperature and model results

  3. Bio-optical profile data report coastal transition zone program, R/V Point Sur, June 15-28, 1987

    NASA Technical Reports Server (NTRS)

    Davis, Curtiss O.; Rhea, W. Joseph

    1990-01-01

    Twenty vertical profiles of the bio-optical properties of the ocean were made during a research cruise on the R/V Point Sur, June 15 to 28, 1987, as part of the Coastal Transition Zone Program off Point Arena, California. Extracted chlorophyll values were also measured at some stations to provide calibration data for the in situ fluorometer. This summary provides investigators with an overview of the data collected. The entire data set is available in digital form.

  4. Spatial and Diel Variability in Photosynthetic and Photoprotective Pigments in Shallow Benthic Communities

    DTIC Science & Technology

    2001-09-30

    acidification with a Turner 10-000R fluorometer. For phycoerythrin and phycocyanin analysis, the sediments were extracted repeatedly with a phosphate...concentrations varied around 20-fold, phycocyanin varied approximately 70-fold. The highest levels of chlorophylls a and c, and phycocyanin were found in...reflected in the wide range of pigment ratios: 46 for chl c/chl a; 94 for phycoerythrin/chl a; and 27 for phycocyanin /chl a. First derivatives of

  5. Frequency domain fluorometry: theory and application.

    PubMed

    Vetromile, Carissa M; Jameson, David M

    2014-01-01

    Frequency domain fluorometry is a widely utilized tool in the physical, chemical, and biological sciences. This chapter focuses on the theory of the method and the practical aspects required to carry out intensity decay, i.e., lifetime measurements on a modern frequency domain fluorometer. Several chemical/biological systems are utilized to illustrate data acquisition protocols. Data analysis procedures and methodologies are also discussed.

  6. Mixing and Transport in the Surfzone

    DTIC Science & Technology

    2008-01-01

    also sample chlrophyl A ( Omand et al, submitted). The dye sampling jetski and fixed fluorometers were deployed at Huntington Beach, as part of the HB06...field experiment. SIO graduate PhD student David Clark, co- advised with Dr Feddersen, is using these observations to characterize surfzone mixing...the similarity theory of turbulence to atmospheric diffusion. Quart. J. Roy. Meteor. Soc., 76, 133–146, 1950 Clark, D.B., F. Feddersen, M. Omand

  7. AUV Turbulence Measurements in the LOCO Field Experiments

    DTIC Science & Technology

    2007-09-30

    addition the vehicle contains a variety of “hotel” sensors which measure pitch , roll , yaw, and other internal dynamical characteristics. This suite...hotel” sensors which measure pitch , roll , yaw, and many other internal characteristics. FFECT TO THE ENVIRONMENT E (1) Because the AUV is battery...upward and downward looking 1.2 mHz ADCP , a FASTCAT CTD, and a Wet Labs BB2F Combination Spectral Backscattering Meter/ Chlorophyll Fluorometer. In

  8. Oceanographic Research

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The PNF-300 Natural Fluorometer is an optical instrument for oceanographic research developed under NASA contract by Biospherical Instruments, Inc. An important innovation for oceanographers, it measures photosynthetic productivity and estimates phytoplankton production less expensively, is non-intrusive and can be used on site - an improved way of estimating ocean productivity. Applications include environmental impact studies, monitoring plankton concentrations in a reservoir, and other research uses.

  9. Multiplex fluorescent immunoassay device based on magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Godjevargova, T. I.; Ivanov, Y. L.; Dinev, D. D.

    2017-02-01

    Immunofluorescent analyzer based compact disc for simultaneous detection of 3 antibiotics in the same milk sample is consisting of two parts: CD-based immunofluorescence kit and optoelectronic fluorometer. Kit consists of 2 parts: Lyophilized immobilized antibodies on supermagnetic nanoparticles in Eppendorf tubes and CD-based microfluidic disk, in which are formed five chamber systems for simultaneous detecting of 5 separate samples. Each system consists of 2 chambers connected by a special micro channel acting as a hydrophobic valve. In the first chamber lyophilised conjugates of 3 antibiotics with accordingly 3 different fluorescent dyes are placed. The second chamber is for detection of fluorescent signal. The optoelectronic fluorometer is comprising of: integrated thermostatic block; mechanical-detecting unit (fluorometer) and block with controlling and visualizing electronics.The disc gets into a second block of the analyzer, where centrifugation is performed and also reporting of the fluorescent signals. This unit comprises a rotor on which the disc is fixed, permanent electromagnet in the form of a ring inserted under the disc and module of 3 LED diodes with emission filters for the relevant wavelengths corresponding to the used fluorescent dyes and 1 integrated photodiode, in front of which is mounted filter with 3 spectral peaks.The signal from the photodiode is detected by the electronic unit which is sensitive "lock-in" amplifier, the engine rotor management, control of thermostatic device and management of periphery of the analyzer, consisting of display and communications with computer.

  10. Swallowable fluorometric capsule for wireless triage of gastrointestinal bleeding.

    PubMed

    Nemiroski, A; Ryou, M; Thompson, C C; Westervelt, R M

    2015-12-07

    Real-time detection of gastrointestinal bleeding remains a major challenge because there does not yet exist a minimally invasive technology that can both i) monitor for blood from an active hemorrhage and ii) uniquely distinguish it from blood left over from an inactive hemorrhage. Such a device would be an important tool for clinical triage. One promising solution, which we have proposed previously, is to inject a fluorescent dye into the blood stream and to use it as a distinctive marker of active bleeding by monitoring leakage into the gastrointestinal tract with a wireless fluorometer. This paper reports, for the first time to our knowledge, the development of a swallowable, wireless capsule with a built-in fluorometer capable of detecting fluorescein in blood, and intended for monitoring gastrointestinal bleeding in the stomach. The embedded, compact fluorometer uses pinholes to define a microliter sensing volume and to eliminate bulky optical components. The proof-of-concept capsule integrates optics, low-noise analog sensing electronics, a microcontroller, battery, and low power Zigbee radio, all into a cylindrical package measuring 11 mm × 27 mm and weighing 10 g. Bench-top experiments demonstrate wireless fluorometry with a limit-of-detection of 20 nM aqueous fluorescein. This device represents a major step towards a technology that would enable simple, rapid detection of active gastrointestinal bleeding, a capability that would save precious time and resources and, ultimately, reduce complications in patients.

  11. Fluorescence characteristics of oil during the Deepwater Horizon oil spill

    NASA Astrophysics Data System (ADS)

    Coble, P. G.; Conmy, R. N.; Wood, M.; Lee, K.; Kepkay, P.; Li, Z.

    2010-12-01

    Emergency responders, agencies and researchers have tracked oil spilled during the Deepwater Horizon event using a number of techniques, including fluorescence, particle size and chemical analyses. Even though current protocols call for the use of in situ fluorometers to detect the presence of oil throughout the water column, these fluorometers have not been designed to yield information on changes in oil optical properties as it weathers and is chemically and/or physically dispersed. Multi-wavelength (Excitation Emission Matrix or multiple fixed wavelength) fluorometers and particle size analyzers are required to accurately monitor these changing properties in situ and in samples containing the oil suspended as droplets in seawater. Findings reported by the Unified Command Joint Analysis Group on fluorescence, particle size (by LISST) and chemical analysis data will be used to delineate changing oil properties and the results obtained from laboratory experiments using suspensions of Deepwater Horizon source oil will be compared to the environmental data (including information collected via ROV at the well head). The Deepwater Horizon spill was unprecedented in terms of magnitude, depth of the spill and subsurface dispersant application. The work presented here will improve current protocols by highlighting the critical fluorescence wavelengths needed to accurately track oil through marine systems.

  12. Experimental in vivo measurements of light emission in plants: a perspective dedicated to David Walker.

    PubMed

    Kalaji, Hazem M; Goltsev, Vasilij; Bosa, Karolina; Allakhverdiev, Suleyman I; Strasser, Reto J; Govindjee

    2012-12-01

    This review is dedicated to David Walker (1928-2012), a pioneer in the field of photosynthesis and chlorophyll fluorescence. We begin this review by presenting the history of light emission studies, from the ancient times. Light emission from plants is of several kinds: prompt fluorescence (PF), delayed fluorescence (DF), thermoluminescence, and phosphorescence. In this article, we focus on PF and DF. Chlorophyll a fluorescence measurements have been used for more than 80 years to study photosynthesis, particularly photosystem II (PSII) since 1961. This technique has become a regular trusted probe in agricultural and biological research. Many measured and calculated parameters are good biomarkers or indicators of plant tolerance to different abiotic and biotic stressors. This would never have been possible without the rapid development of new fluorometers. To date, most of these instruments are based mainly on two different operational principles for measuring variable chlorophyll a fluorescence: (1) a PF signal produced following a pulse-amplitude-modulated excitation and (2) a PF signal emitted during a strong continuous actinic excitation. In addition to fluorometers, other instruments have been developed to measure additional signals, such as DF, originating from PSII, and light-induced absorbance changes due to the photooxidation of P700, from PSI, measured as the absorption decrease (photobleaching) at about 705 nm, or increase at 820 nm. In this review, the technical and theoretical basis of newly developed instruments, allowing for simultaneous measurement of the PF and the DF as well as other parameters is discussed. Special emphasis has been given to a description of comparative measurements on PF and DF. However, DF has been discussed in greater details, since it is much less used and less known than PF, but has a great potential to provide useful qualitative new information on the back reactions of PSII electron transfer. A review concerning the history

  13. [Theoretical study of fluorescence of photosynthetic pigments at complex dependence of intensity of exciting light on time].

    PubMed

    Alekseev, A A; Belov, A A; Kirzhanov, D V; Kukushkin, A K

    2012-01-01

    Now the methods using the radiance with complex dependence of light intensity on time are applied to research of photosynthesis by means of fluorescence, exciting photosynthetic pigments. One of these methods is applied in PAM-fluorometers--the commercial devices currently widely used to investigate a state of photosynthesizing systems. However, if excitation is performed in this way, the question, what components of fluorescence are registered at an output of such devices, remains to be open-ended. In this work an attempt to analyse this task has been made.

  14. An assay for measurement of protein adsorption to glass vials.

    PubMed

    Varmette, Elizabeth; Strony, Brianne; Haines, Daniel; Redkar, Rajendra

    2010-01-01

    Protein adsorption to primary packaging is one of the problems faced by biopharmaceutical drug companies. An assay was developed to quantify loss of proteins to glass vial surfaces. The assay involves the labeling of protein with a fluorescent dye, incubation of the labeled protein with the vial surface, elution of the adsorbed protein using a stripping buffer, and determination of fluorescence of the adsorbed protein using a fluorometer. The assay is simple to set up, accurate, sensitive, and flexible. The assay can be modified for indirect measurement of protein adsorption and offers an attractive alternative for researchers to quantify protein adsorption to glass vials and syringes.

  15. CTD Observation in the Coastal Transition Zone off Northern California from R/V Wecoma, July to August 1988

    DTIC Science & Technology

    1989-03-01

    no correction was applied to the CTD pressure data of W8807A and W8806B. Water samples were collected at each station from Niskin bottles at two or...twelve 5-liter Niskin bottles . Mounted adjacent to the CTD were a Sea Tech 25 cm transmissometer (s/n 33D) and a Sea Tech Fluorometer (s/n 48). The CTD was...the samples were recorded at the actual depth at which each bottle was tripped. Duplicate salinity samples were drawn from selected bottles and stored

  16. Mixing and Transport in the Surfzone

    DTIC Science & Technology

    2009-01-01

    chlrophyl A ( Omand et al, 2009). The dye sampling jetski and fixed fluorometers were deployed at Huntington Beach, as part of the HB06 field experiment...SIO graduate PhD student David Clark, co-advised with Dr Feddersen, is using these observations to characterize surfzone mixing (figure 2). 2...1998 Omand , M., F. Feddersen, D.B. Clark, P.J.S. Franks, J. J. Leichter , and R.T. Guza, The Influence of Bubbles and Sand on Chlorophyll-a

  17. Evaluation of a laser-induced fluorescence system for uranium analysis

    SciTech Connect

    White, L.E.

    1980-05-01

    A laser-induced fluorescence method for total uranium analysis of industrial process waters, waste waters, and leachates has been evaluated as a possible alternative for the normal, sodium fluoride and lithium fluoride, flame-fusion fluorescence method currently employed. Since the lower reporting limit of the laser fluorometer is on the order of 0.05 ..mu..g/L, samples for normal analysis can usually be diluted from 100 to 1000 fold which virtually eliminates interferences from quenching substances. Also, since the uranium determination is done in aqueous solution, laser-induced fluorescence entirely eliminates the need for organic extraction and the subsequent fusion process.

  18. Fluorometric assay for aflatoxins

    SciTech Connect

    Chakrabarti, A.G.

    1984-11-01

    The method that is now widely adopted by the government laboratories for the assay of individual aflatoxin components (B/sub 1/, B/sub 2/, G/sub 1/, and G/sub 2/) utilizes a TLC technique. The extraction and clean-up steps of this technique were further researched but the method is still time consuming. It is, therefore, very important to develop a rapid and accurate assay technique for aflatoxins. The current research proposes a technique which utilizes a Turner Fluorometer.

  19. Fluorescence Spectroscopy in a Shoebox

    NASA Astrophysics Data System (ADS)

    Farooq Wahab, M.

    2007-08-01

    This article describes construction of a simple, inexpensive fluorometer. It utilizes a flashlight or sunlight source, highlighter marker ink, bowl of water with mirror as dispersing element, and colored cellophane sheets as filters. The human eye is used as a detector. This apparatus is used to demonstrate important concepts related to fluorescence spectroscopy. Using ink from a highlighter marker, one can demonstrate the difference between light scattering and fluorescence emission, the need for an intense light source, phenomenon of the Stokes shift, the choice of filters, the preferred geometry of excitation source and emission detector, and the low detection limits that can be achieved by fluorescence measurements. By reflecting the fluorescence emission from a compact disk, it can be seen that the light emitted by molecules is not monochromatic. Furthermore, a spectrofluorometer is constructed using gratings made from a DVD or a CD. The shoebox fluorometer and spectrofluorometer can serve as useful teaching aids in places where commercial instruments are not available, and it avoids the black box problem of modern instruments.

  20. Exposing water samples to ultraviolet light improves fluorometry for detecting human fecal contamination.

    PubMed

    Hartel, Peter G; Hagedorn, Charles; McDonald, Jennifer L; Fisher, Jared A; Saluta, Michael A; Dickerson, Jerold W; Gentit, Lisa C; Smith, Steven L; Mantripragada, Nehru S; Ritter, Kerry J; Belcher, Carolyn N

    2007-08-01

    Fluorometry identifies human fecal contamination by detecting optical brighteners in environmental waters. Because optical brighteners are sensitive to sunlight, we determined if we could improve fluorometry by exposing water samples to ultraviolet (UV) light to differentiate between optical brighteners and other fluorescing organic compounds. Optical brighteners were likely present when the relative percentage difference in fluorometric value of the water before and after UV light exposure was >30% (glass cuvettes, 30 min exposure) or >15% (polymethacrylate cuvettes, 5 min exposure). In a blind study, we correctly identified the presence or absence of optical brighteners in 178 of 180 (99%) of the samples tested with a more expensive field fluorometer and in 175 of 180 (97%) of the samples tested with a less expensive handheld fluorometer. In the field, the method correctly identified two negative and three positive locations for human fecal contamination. When combined with counts of fecal bacteria, the new fluorometric method may be a simple, quick, and easy way to identify human fecal contamination in environmental waters.

  1. Spatial extent and dissipation of the deep chlorophyll layer in Lake Ontario during the Lake Ontario lower foodweb assessment, 2003 and 2008

    USGS Publications Warehouse

    Watkins, J. M.; Weidel, Brian M.; Rudstam, L. G.; Holek, K. T.

    2014-01-01

    Increasing water clarity in Lake Ontario has led to a vertical redistribution of phytoplankton and an increased importance of the deep chlorophyll layer in overall primary productivity. We used in situ fluorometer profiles collected in lakewide surveys of Lake Ontario in 2008 to assess the spatial extent and intensity of the deep chlorophyll layer. In situ fluorometer data were corrected with extracted chlorophyll data using paired samples from Lake Ontario collected in August 2008. The deep chlorophyll layer was present offshore during the stratified conditions of late July 2008 with maximum values from 4-13 μg l-1 corrected chlorophyll a at 10 to 17 m depth within the metalimnion. Deep chlorophyll layer was closely associated with the base of the thermocline and a subsurface maximum of dissolved oxygen, indicating the feature's importance as a growth and productivity maximum. Crucial to the deep chlorophyll layer formation, the photic zone extended deeper than the surface mixed layer in mid-summer. The layer extended through most of the offshore in July 2008, but was not present in the easternmost transect that had a deeper surface mixed layer. By early September 2008, the lakewide deep chlorophyll layer had dissipated. A similar formation and dissipation was observed in the lakewide survey of Lake Ontario in 2003.

  2. Determination of aflatoxins in grains and raw peanuts by a rapid procedure with fluorometric analysis.

    PubMed

    Malone, B R; Humphrey, C W; Romer, T R; Richard, J L

    2000-01-01

    A rapid, quantitative, inexpensive, and efficient method was developed to determine aflatoxins in corn, corn meal, popcorn, rice, wheat, cottonseed, and peanuts. Samples are ground and extracted with methanol-water (80 + 20). A portion of the extract is cleaned up by passage through a solid-phase separatory column, 500 microL purified extract is derivatized with a bromine reagent, and fluorescence of the solution is immediately quantified with a calibrated fluorometer containing a broad wavelength pulsed xenon light source. This method can quantify aflatoxin from 5 to 5000 ppb without dilution and was linear when applied to samples of noncontaminated corn spiked at 0 to 5000 micrograms aflatoxin B1/g. Correlation coefficients of the method with LC for multiple analyses for corn (n = 34), cottonseed (n = 32), and peanuts (n = 11) were 0.999, 0.995, and 0.980, respectively. Individual analyses may be conducted in less than 5 min, and grouping of samples is unnecessary. The sensitivity of the method for corn is 5 ppb and the fluorometer, under the operating conditions, has a limit of detection of 0.6 ng aflatoxin B1.

  3. A hand-held electronic tongue based on fluorometry for taste assessment of tea.

    PubMed

    Chang, Kuang-Hua; Chen, Richie L C; Hsieh, Bo-Chuan; Chen, Po-Chung; Hsiao, Hsien-Yi; Nieh, Chi-Hua; Cheng, Tzong-Jih

    2010-12-15

    A hand-held electronic tongue was developed for determining taste levels of astringency and umami in tea infusions. The sensing principles are based on quenching the fluorescence of 3-aminophthalate by tannin, and the fluorogenic reaction of o-phthalaldehyde (OPA) with amino acids to determine astringency and umami levels, respectively. Both reactions were measured by a single fluorescence sensing system with same excitation and emission wavelengths (340/425 nm). This work describes in detail the design, fabrication, and performance evaluation of a hand-held fluorometer with an ultra-violet light emitted diode (UVLED) and a photo-detector with a filter built-in. The dimension and the weight of proposed electronic tongue prototype are only 120×60×65 mm(3) and 150 g, respectively. The detection limits of this prototype for theanine and tannic acid were 0.2 μg/ml and 1 μg/ml, respectively. Correlation coefficients of this prototype compared with a commercial fluorescence instrument are both higher than 0.995 in determinations of tannin acid and theanine. Linear detection ranges of the hand-held fluorometer for tannic acid and theanine are 1-20 μg/ml and 0.2-10 μg/ml (CV<5%, n=3), respectively. A specified taste indicator for tea, defined as ratio of umami to astringency, was adopted here to effectively distinguish flavour quality of partially fermented Oolong teas.

  4. Lightweight Fiber Optic Gas Sensor for Monitoring Regenerative Food Production

    NASA Technical Reports Server (NTRS)

    Schmidlin, Edward; Goswami, Kisholoy

    1995-01-01

    In this final report, Physical Optics Corporation (POC) describes its development of sensors for oxygen, carbon dioxide, and relative humidity. POC has constructed a phase fluorometer that can detect oxygen over the full concentration range from 0 percent to 100 percent. Phase-based measurements offer distinct advantages, such as immunity to source fluctuation, photobleaching, and leaching. All optics, optoelectronics, power supply, and the printed circuit board are included in a single box; the only external connections to the fluorometer are the optical fiber sensor and a power cord. The indicator-based carbon dioxide sensor is also suitable for short-term and discrete measurements over the concentration range from 0 percent to 100 percent. The optical fiber-based humidity sensor contains a porous core for direct interaction of the light beam with water vapor within fiber pores; the detection range for the humidity sensor is 10 percent to 100 percent, and response time is under five minutes. POC is currently pursuing the commercialization of these oxygen and carbon dioxide sensors for environmental applications.

  5. Development and characterization of the NanoOrange protein quantitation assay: a fluorescence-based assay of proteins in solution.

    PubMed

    Jones, Laurie J; Haugland, Richard P; Singer, Victoria L

    2003-04-01

    We developed a sensitive fluorescence assay for the quantitation of proteins in solution using the NanoOrange reagent, a merocyanine dye that produces a large increase in fluorescence quantum yield upon interaction with detergent-coated proteins. The NanoOrange assay allowed for the detection of 10 ng/mL to 10 micrograms/mL protein with a standard fluorometer, offering a broad, dynamic quantitation range and improved sensitivity relative to absorption-based protein solution assays. The protein-to-protein variability of the NanoOrange assay was comparable to those of standard assays, including Lowry, bicinchoninic acid, and Bradford procedures. We also found that the NanoOrange assay is useful for detecting relatively small proteins or large peptides, such as aprotinin and insulin. The assay was somewhat sensitive to the presence of several common contaminants found in protein preparations such as salts and detergents; however, it was insensitive to the presence of reducing agents, nucleic acids, and free amino acids. The simple assay protocol is suitable for automation. Samples are briefly heated in the presence of dye in a detergent-containing diluent, allowed to cool to room temperature, and fluorescence is measured using 485-nm excitation and 590-nm emission wavelengths. Therefore, the NanoOrange assay is well suited for use with standard fluorescence microplate readers, fluorometers, and some laser scanners.

  6. Spatial extent and dissipation of the deep chlorophyll layer in Lake Ontario during the Lake Ontario lower foodweb assessment, 2003 and 2008

    USGS Publications Warehouse

    Watkins, J. M.; Weidel, Brian M.; Rudstam, L. G.; Holek, K. T.

    2014-01-01

    Increasing water clarity in Lake Ontario has led to a vertical redistribution of phytoplankton and an increased importance of the deep chlorophyll layer in overall primary productivity. We used in situ fluorometer profiles collected in lakewide surveys of Lake Ontario in 2008 to assess the spatial extent and intensity of the deep chlorophyll layer. In situ fluorometer data were corrected with extracted chlorophyll data using paired samples from Lake Ontario collected in August 2008. The deep chlorophyll layer was present offshore during the stratified conditions of late July 2008 with maximum values from 4–20 μg l−1 corrected chlorophyll a at 10 to 17 m depth within the metalimnion. Deep chlorophyll layer was closely associated with the base of the thermocline and a subsurface maximum of dissolved oxygen, indicating the feature's importance as a growth and productivity maximum. Crucial to the deep chlorophyll layer formation, the photic zone extended deeper than the surface mixed layer in mid-summer. The layer extended through most of the offshore in July 2008, but was not present in the easternmost transect that had a deeper surface mixed layer. By early September 2008, the lakewide deep chlorophyll layer had dissipated. A similar formation and dissipation was observed in the lakewide survey of Lake Ontario in 2003.

  7. Making Sense of Plant Health

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Ciencia, Inc. created a new device, known as a Portable Photosynthesis Analyzer, or Phase Fluorometer, that provides real-time data about the photochemical efficiency of phytoplankton and other plant forms. The commercial version of this technology is used for photosynthesis research and offers major benefits to the field of life science. This new instrument is the first portable instrument of its kind. Through a license agreement with Ciencia, Oriel Instruments, of Stratford, Connecticut, manufactures and markets the commercial version of the instrument under the name LifeSense.TMLifeSense is a 70 MHz single-frequency fluorometer that offers unrivaled capabilities for fluorescence lifetime sensing and analysis. LifeSense provides information about all varieties of photosynthetic systems. Photosynthesis research contributes important health assessments about the plant, be it phytoplankton or a higher form of plant life. With its unique sensing capabilities, LifeSense furnishes data regarding the yield of a plant's photochemistry, as well as its levels of photosynthetic activity. The user can then gain an extremely accurate estimate of the plant's chlorophyll biomass, primary production rates, and a general overview of the plant's physiological condition.

  8. Effects of habitat light conditions on the excitation quenching pathways in desiccating Haberlea rhodopensis leaves: an Intelligent FluoroSensor study.

    PubMed

    Solti, Ádám; Lenk, Sándor; Mihailova, Gergana; Mayer, Péter; Barócsi, Attila; Georgieva, Katya

    2014-01-05

    Resurrection plants can survive dehydration to air-dry state, thus they are excellent models of understanding drought and dehydration tolerance mechanisms. Haberlea rhodopensis, a chlorophyll-retaining resurrection plant, can survive desiccation to relative water content below 10%. Leaves, detached from plants of sun and shade habitats, were moderately (∼50%) dehydrated in darkness. During desiccation, chlorophyll a fluorescence was detected by the recently innovated wireless Intelligent FluoroSensor (IFS) chlorophyll fluorometer, working with three different detectors: a pulse-amplitude-modulated (PAM) broadband channel and two channels to measure non-modulated red and far-red fluorescence. No change in area-based chlorophyll content of leaves was observed. The maximal quantum efficiency of photosystem II decreased gradually in both shade and sun leaves. Shade leaves could not increase antennae-based quenching, thus inactivated photosystem II took part in quenching of excess irradiation. Sun leaves seemed to be pre-adapted to quench excess light as they established an intensive increase in antennae-based non-photochemical quenching parallel to desiccation. The higher far-red to red antennae-based quenching may sign light-harvesting complex reorganization. Thus, compared to PAM, IFS chlorophyll fluorometer has additional benefits including (i) parallel estimation of changes in the Chl content and (ii) prediction of underlying processes of excitation energy quenching.

  9. First steps in photophysics. I. Fluorescence yield and radiative rate coefficient of 9,10-bis(phenylethynyl)anthracene in paraffins.

    PubMed

    Demeter, Attila

    2014-10-30

    The fluorescence quantum yield of 9,10-bis(phenylethynyl)anthracene (BPEA) is almost unity in every examined solvent. Using different hydrocarbons, one can make a convenient and sufficiently accurate experimental test for determination of the extent of the refractive index correction needed in fluorescence quantum yield determination on a given fluorometer. By comparison of the measurements in n-pentane-cis-decaline or n-hexane-toluene solvent pairs, the requirement of the n(2) correction is confirmed for most of the fluorometers; however, for one of the examined pieces of equipment the necessary correction proved to be slightly lower. By excited state's lifetime measurements, the refractive index dependence of the fluorescence rate coefficient was reexamined. At 25 °C for BPEA the relationship is in agreement with Bakhshiev's prediction: the experimentally determined exponent of n in the rate coefficient deriving equation is around 1.32 using different paraffins as solvents. The negative temperature coefficient of the radiative rate in part originates from the temperature dependence of the refractive index, while also a small intrinsic contribution has been found.

  10. Surface Fluorescence Studies of Tissue Mitochondrial Redox State in Isolated Perfused Rat Lungs

    PubMed Central

    Staniszewski, Kevin; Audi, Said H.; Sepehr, Reyhaneh; Jacobs, Elizabeth R.; Ranji, Mahsa

    2012-01-01

    We designed a fiber-optic-based optoelectronic fluorometer to measure emitted fluorescence from the auto-fluorescent electron carriers NADH and FAD of the mitochondrial electron transport chain (ETC). The ratio of NADH to FAD is called the redox ratio (RR = NADH/FAD) and is an indicator of the oxidoreductive state of tissue. We evaluated the fluorometer by measuring the fluorescence intensities of NADH and FAD at the surface of isolated, perfused rat lungs. Alterations of lung mitochondrial metabolic state were achieved by the addition of rotenone (complex I inhibitor), potassium cyanide (KCN, complex IV inhibitor) and/or pentachlorophenol (PCP, uncoupler) into the perfusate recirculating through the lung. Rotenone- or KCN-containing perfusate increased RR by 21% and 30%, respectively. In contrast, PCP-containing perfusate decreased RR by 27%. These changes are consistent with the established effects of rotenone, KCN, and PCP on the redox status of the ETC. Addition of blood to perfusate quenched NADH and FAD signal, but had no effect of RR. This study demonstrates the capacity of fluorometry to detect a change in mitochondrial redox state in isolated perfused lungs, and suggests the potential of fluorometry for use in in vivo experiments to extract a sensitive measure of lung tissue’s health in real-time. PMID:23238793

  11. Relationship between chlorophyll a concentration, light attenuation and diving depth of the Southern elephant seal Mirounga leonina.

    PubMed

    Jaud, Thomas; Dragon, Anne-Cécile; Garcia, Jade Vacquie; Guinet, Christophe

    2012-01-01

    Recently, a number of Antarctic marine environmental studies have used oceanographic parameters collected from instrumented top predators for ecological and physical information. Phytoplankton concentration is generally quantified through active measurement of chlorophyll fluorescence. In this study, light absorption coefficient (K(0.75)) was used as an indicator of phytoplankton concentration. This measurement, easy to obtain and requiring low electric power, allows for assessing of the fine scale horizontal structuring of phytoplankton. As part of this study, Southern elephant seals (SES) were simultaneously equipped with a fluorometer and a light logger. Along the SES tracks, variations in K(0.75) were strongly correlated with chlorophyll, a concentration measured by the fluorometer within the euphotic layer. With regards to SES foraging behaviour, bottom depth of the seal's dive was highly dependent on light intensity at 150 m, indicating that the vertical distribution of SES's prey such as myctophids is tightly related to light level. Therefore, change in phytoplankton concentration may not only have a direct effect on SES's prey abundance but may also determine their vertical accessibility with likely consequences on SES foraging efficiency.

  12. Relationship between Chlorophyll a Concentration, Light Attenuation and Diving Depth of the Southern Elephant Seal Mirounga leonina

    PubMed Central

    Jaud, Thomas; Dragon, Anne-Cécile; Garcia, Jade Vacquie; Guinet, Christophe

    2012-01-01

    Recently, a number of Antarctic marine environmental studies have used oceanographic parameters collected from instrumented top predators for ecological and physical information. Phytoplankton concentration is generally quantified through active measurement of chlorophyll fluorescence. In this study, light absorption coefficient (K0.75) was used as an indicator of phytoplankton concentration. This measurement, easy to obtain and requiring low electric power, allows for assessing of the fine scale horizontal structuring of phytoplankton. As part of this study, Southern elephant seals (SES) were simultaneously equipped with a fluorometer and a light logger. Along the SES tracks, variations in K0.75 were strongly correlated with chlorophyll, a concentration measured by the fluorometer within the euphotic layer. With regards to SES foraging behaviour, bottom depth of the seal’s dive was highly dependent on light intensity at 150 m, indicating that the vertical distribution of SES’s prey such as myctophids is tightly related to light level. Therefore, change in phytoplankton concentration may not only have a direct effect on SES’s prey abundance but may also determine their vertical accessibility with likely consequences on SES foraging efficiency. PMID:23082166

  13. Satellite Remote Sensing Studies of Biological and Biogeochemical Processing in the Ocean

    NASA Technical Reports Server (NTRS)

    Vernet, Maria

    2001-01-01

    The remote sensing of phycoerythrin-containing phytoplankton by ocean color was evaluated. Phycoerythrin (PE) can be remotely sensed by three methods: surface reflectance (Sathyendranath et al. 1994), by laser-activated fluorescence (Hoge and Swift 1986) and by passive fluorescence (Letelier et al. 1996). In collaboration with Dr. Frank Hoge and Robert Swift during Dr. Maria Vernet's tenure as Senior Visiting Scientist at Wallops Island, the active and passive methods were studied, in particular the detection of PE fluorescence and spectral reflectance from airborne LIDAR (AOL). Airborne instrumentation allows for more detailed and flexible sampling of the ocean surface than satellites thus providing the ideal platform to test model and develop algorithms than can later be applied to ocean color by satellites such as TERRA and AQUA. Dr. Vernet's contribution to the Wallops team included determination of PE in the water column, in conjunction with AOL flights in the North Atlantic Bight. In addition, a new flow-through fluorometer for PE determination by fluorescence was tested and calibrated. Results: several goals were achieved during this period. Cruises to the California Current, North Atlantic Bight, Gulf of Maine and Chesapeake Bay provided sampling under different oceanographic and optical conditions. The ships carried the flow-through fluorometer and samples for the determination of PE were obtained from the flow-through flow. The AOL was flown over the ship's track, usually several flights during the cruise, weather permitting.

  14. Frequency domain fluorometry with pulsed light-emitting diodes.

    PubMed

    Herman, Petr; Vecer, Jaroslav

    2008-01-01

    We present a simple way to extend the time resolution of a standard frequency domain (FD) fluorometer by use of pulsed light-emitting diodes (LEDs) as an excitation source. High temporal resolution of the multifrequency FD method requires the excitation light to be modulated up to the highest possible frequencies with high modulation depth. We used harmonic content of subnanosecond-pulsed LEDs for generation of modulated excitation light. By a replacement of the light source, the upper frequency limit increased to 500-600 MHz, which is almost triple the frequency limit of the standard FD fluorometer equipped with an ordinary photomultiplier tube and an electro-optical modulator. Besides the increased time resolution, this approach allowed for elimination of a light modulator with an associated synthesizer and radio frequency power amplifier that are normally required for FD measurements with continuous wave light sources. Performance of the instrument with pulsed LED excitation is demonstrated on several examples of ultraviolet-excited fluorescence decays. We show that pulsed LEDs can serve as an inexpensive alternative to pulsed laser sources for FD fluorescence spectroscopy.

  15. Fluorometry of ischemia reperfusion injury in rat lungs in vivo

    NASA Astrophysics Data System (ADS)

    Sepehr, R.; Staniszewski, K.; Jacobs, E. R.; Audi, S.; Ranji, Mahsa

    2013-02-01

    Previously we demonstrated the utility of optical fluorometry to evaluate lung tissue mitochondrial redox state in isolated perfused rats lungs under various chemically-induced respiratory states. The objective of this study was to evaluate the effect of acute ischemia on lung tissue mitochondrial redox state in vivo using optical fluorometry. Under ischemic conditions, insufficient oxygen supply to the mitochondrial chain should reduce the mitochondrial redox state calculated from the ratio of the auto-fluorescent mitochondrial metabolic coenzymes NADH (Nicotinamide Adenine Dinucleotide) and FAD (Flavoprotein Adenine Dinucleotide). The chest of anesthetized, and mechanically ventilated Sprague-Dawley rat was opened to induce acute ischemia by clamping the left hilum to block both blood flow and ventilation to one lung for approximately 10 minutes. NADH and FAD fluorescent signals were recorded continuously in a dark room via a fluorometer probe placed on the pleural surface of the left lung. Acute ischemia caused a decrease in FAD and an increase in NADH, which resulted in an increase in the mitochondrial redox ratio (RR=NADH/FAD). Restoration of blood flow and ventilation by unclamping the left hilum returned the RR back to its baseline. These results (increase in RR under ischemia) show promise for the fluorometer to be used in a clinical setting for evaluating the effect of pulmonary ischemia-reperfusion on lung tissue mitochondrial redox state in real time.

  16. An annual cycle of phytoplankton biomass in the Arabian Sea, 1994 1995, as determined by moored optical sensors

    NASA Astrophysics Data System (ADS)

    Kinkade, C. S.; Marra, J.; Dickey, T. D.; Weller, R.

    A surface-to-bottom mooring in the central Arabian Sea (15.5°N, 61.5°E) deployed from October 1994 to October 1995, included fluorometers, PAR irradiance sensors, Lu 683 sensors, and a spectral radiometer. An annual cycle of phytoplankton biomass was determined by transforming signals from the optical sensors into chlorophyll a (chl a). Half-yearly phytoplankton blooms with water-column stratification were observed near the end of each monsoon, as well as biomass increases in response to mesoscale flow features. During the Northeast Monsoon, the integrate water-column chl a rose from 15 to 25 mg m -2, while during the Southwest Monsoon, chl a increased from 15 to a maximum >40 mg m -2. We present an empirical relationship between the ratio of downwelling Ed443/ Ed550 (blue to green wavelength ratio) and integral euphotic zone chl a determined by moored fluorometers ( r2=0.73). There is a more significant relationship between Ed443/ Ed550 measured at one depth in the water column (65 m) and the average vertical attenuation coefficient for PAR (K PAR) between 0 and 65 m ( r2=0.845). Because biofouling was a significant problem at times, data return from any one sensor was incomplete. However, optical sensor/data intercomparison helped fill gaps while permitting investigation of the temporal variability in observed phytoplankton biomass.

  17. Chlorophyll-a determination via continuous measurement of plankton fluorescence: methodology development.

    PubMed

    Pinto, A M; Von Sperling, E; Moreira, R M

    2001-11-01

    A methodology is presented for the continuous measurement of chlorophyll-a concentration due to plankton, in surface water environments. A Turner 10-AU fluorometer equipped with the F4T5.B2/BP lamp (blue lamp), a Cs 5-60 equivalent excitation path filter, and a 680 nm emission filter, has been used. This configuration allows the in vivo, in situ determination of chlorophyll-a by measuring the fluorescence due to the pigments. In field work the fluorometer, data logging and positioning equipment were placed aboard a manageable boat which navigated following a scheme of regularly spaced crossings. Some water samples were collected during the measurement for laboratory chlorophyll-a measurements by the spectrophotometric method, thus providing for calibration and comparison. Spatial chlorophyll-a concentration distributions can be easily defined in large volumes, such as reservoirs, etc. Two distinct environments have been monitored: in the Vargem das Flores reservoir chlorophyll-a concentrations varied between 0.7 and 2.6 mg/m3, whereas in the Lagoa Santa lake these values lied in the 12 to 18 mg/m3 range. The simplicity, versatility and economy of the method, added to the large amount of data that can be gathered in a single run, clearly justify its use in field environmental studies.

  18. Quantification of DNA Extracted from Formalin Fixed Paraffin-Embeded Tissue Comparison of Three Techniques: Effect on PCR Efficiency

    PubMed Central

    Panigrahi, Manoj Kumar; Suryavanshi, Moushumi; Mehta, Anurag; Saikia, Kandarpa Kumar

    2016-01-01

    Introduction Mutation detection from Formalin Fixed Paraffin-Embedding (FFPE) tissue in molecular lab became a necessary tool for defining potential targeted drug. Accurate quantification of DNA extracted from FFPE tissue is necessary for downstream applications like Polymerase Chain Reaction (PCR), sequencing etc. Aim To check and define which method for FFPE DNA quantification is suitable for downstream processes. Materials and Methods In this experimental experience study Biorad Smartspec Plus spectrophotomery, Qubit Fluorometer, and Qiagen Rotorgene qPCR was used to compare 20 FFPE DNA quantification in Rajiv Gandhi Cancer Institute and Research Centre, in 2015 and quantified amount of DNA used for PCR reaction. Results The average concentration of DNA extracted from FFPE tissue measured using the spectrophotometer was much higher than the concentration measured using the Qubit Fluorometer and qPCR. Conclusion Results varied depending upon the technique used. A fluorometric analysis may be more suitable for quantification of DNA samples extracted from FFPE tissue compared with spectrophotometric analysis. But qPCR is the best technique because it details DNA quantity along with quality of amplifiable DNA from FFPE tissue. PMID:27790419

  19. An alternative method for correcting fluorescence quenching

    NASA Astrophysics Data System (ADS)

    Biermann, L.; Guinet, C.; Bester, M.; Brierley, A.; Boehme, L.

    2015-01-01

    Under high light intensity, phytoplankton protect their photosystems from bleaching through non-photochemical quenching processes. The consequence of this is suppression of fluorescence emission, which must be corrected when measuring in situ yield with fluorometers. We present data from the Southern Ocean, collected over five austral summers by 19 southern elephant seals tagged with fluorometers. Conventionally, fluorescence data collected during the day (quenched) were corrected using the limit of the mixed layer, assuming that phytoplankton are uniformly mixed from the surface to this depth. However, distinct deep fluorescence maxima were measured in approximately 30% of the night (unquenched) data. To account for the evidence that chlorophyll is not uniformly mixed in the upper layer, we propose correcting from the limit of the euphotic zone, defined as the depth at which photosynthetically available radiation is ~ 1% of the surface value. Mixed layer depth exceeded euphotic depth over 80% of the time. Under these conditions, quenching was corrected from the depth of the remotely derived euphotic zone Zeu, and compared with fluorescence corrected from the depth of the density-derived mixed layer. Deep fluorescence maxima were evident in only 10% of the day data when correcting from mixed layer depth. This was doubled to 21% when correcting from Zeu, more closely matching the unquenched (night) data. Furthermore, correcting from Zeu served to conserve non-uniform chlorophyll features found between the 1% light level and mixed layer depth.

  20. Stream periphyton responses to mesocosm treatments of ...

    EPA Pesticide Factsheets

    A stream mesocosm experiment was designed to compare biotic responses among streams exposed to an equal excess specific conductivity target of 850 µS/cm relative to a control that was set for 200 µS/cm and three treatments comprised of different major ion contents. Each treatment and the control was replicated 4 times at the mesocosm scale (16 mesocosms total). The treatments were based on dosing the background mesocosm water, a continuous flow-through mixture of natural river water and reverse osmosis treated water, with stock salt solutions prepared from 1) a mixture of sodium chloride and calcium chloride (Na/Cl chloride), 2) sodium bicarbonate, and 3) magnesium sulfate. The realized average specific conductance over the first 28d of continuous dosing was 827, 829, and 847 µS/cm, for the chloride, bicarbonate, and sulfate based treatments, respectively, and did not differ significantly. The controls averaged 183 µS/cm. Here we focus on comparing stream periphyton communities across treatments based on measurements obtained from a Pulse-Amplitude Modulated (PAM) fluorometer. The fluorometer is used in situ and with built in algorithms distributes the total aerial algal biomass (µg/cm2) of the periphyton among cyanobacteria, diatoms, and green algae. A measurement is recorded in a matter of seconds and, therefore, many different locations can be measured with in each mesocosm at a high return frequency. Eight locations within each of the 1 m2 (0.3 m W x 3

  1. An Automated Method for the Optical Characterization of Dissolved Organic Matter in a Rapidly Suburbanizing Watershed, Southeastern New Hampshire

    NASA Astrophysics Data System (ADS)

    Gettel, G. M.; McDowell, W.; Pisani, O.

    2006-12-01

    Dissolved organic matter (DOM) is exported from watersheds to downstream ecosystems where it can contribute to eutrophication problems by enhancing microbial respiration and lowering oxygen levels. DOM quality affects microbial respiration; however, little is known about how watershed processes affect the quality of DOM export. In order to document temporal and spatial variability in DOM quality at the watershed scale, we are developing a method to automate the optical characterization of DOM in the Lamprey River watershed in southeastern New Hampshire. This method employs a refrigerated autosampler and column heater associated with a Shimadzu high-pressure liquid chromatograph (HPLC) with a photo-diode array (PDA) UV absorbance detector and an in-line Horiba Jobin Yvon Fluoromax 3 fluorometer capable of 3D excitation- emission scans (EEM). One advantage of this method is that the HPLC flow-through cell in the fluorometer reduces inner-filter effects due to its small volume. Furthermore, specific UV absorbance or SUVA can also be calculated because an in-line UV PDA is used. We found that a number of fluorescence indices are related to DOC, DON, or NO3 concentrations throughout the Lamprey River watershed. For example, Fluorescence Index (F.I.), an indicator of autochthonous sources of DOM, is positively correlated with nitrate and negatively correlated with DOC concentrations (R2=0.95; p<0.01; R2=0.86; p<0.05 respectively). The highest F.I. occurred in the highest-population density sub-basin with the highest nitrate concentrations, while the lowest F.I. occurred in the lowest-population density sub-basin with highest DOC concentrations. These results indicate that nitrate may increase within-stream generation of DOC at high- population sites while DOC from low-population, low-nitrate sites is predominately allochthonous. This allows DOM characterization to be performed in conjunction with weekly and monthly monitoring of many water quality parameters and to be

  2. Submersible optical sensors exposed to chemically dispersed crude oil: wave tank simulations for improved oil spill monitoring.

    PubMed

    Conmy, Robyn N; Coble, Paula G; Farr, James; Wood, A Michelle; Lee, Kenneth; Pegau, W Scott; Walsh, Ian D; Koch, Corey R; Abercrombie, Mary I; Miles, M Scott; Lewis, Marlon R; Ryan, Scott A; Robinson, Brian J; King, Thomas L; Kelble, Christopher R; Lacoste, Jordanna

    2014-01-01

    In situ fluorometers were deployed during the Deepwater Horizon (DWH) Gulf of Mexico oil spill to track the subsea oil plume. Uncertainties regarding instrument specifications and capabilities necessitated performance testing of sensors exposed to simulated, dispersed oil plumes. Dynamic ranges of the Chelsea Technologies Group AQUAtracka, Turner Designs Cyclops, Satlantic SUNA and WET Labs, Inc. ECO, exposed to fresh and artificially weathered crude oil, were determined. Sensors were standardized against known oil volumes and total petroleum hydrocarbons and benzene-toluene-ethylbenzene-xylene measurements-both collected during spills, providing oil estimates during wave tank dilution experiments. All sensors estimated oil concentrations down to 300 ppb oil, refuting previous reports. Sensor performance results assist interpretation of DWH oil spill data and formulating future protocols.

  3. Status of Standardization Projects

    DTIC Science & Technology

    1994-06-30

    MS51446 DIGESTION APPARATUS NITROGEN EA A5 943 944 944 A EA MS 99 MB N D 6630 0556 15 MS51447 FLUOROMETER EA A5 943 944 944 A EA MS 99 MB N D 6630 0556... BROILER SLF CLN ELEC GL H5 942 951 943 Y GL YD1 99 GS U 7310 0846 MIL-K-43943A KETTLES STM JKTD TWIN 5 GAL GL H5 942 951 951 A GL 99 GS N 7310 0847...MIL-B-43928A BROILER CONVEYORIZED INFRAR YDV H5 942 952 952 A YDl 99 N 7310 0848 RR-K-195J 1 KETTLE STM JCKTD SS STM HTD GL H5 942 951 951 A GL YDV 99

  4. Quantitative determination of Mg in Al-alloys by ion-exchange TLC

    SciTech Connect

    Petrovic, M.; Kastelan-Macan, M. . Lab. for Analytical Chemistry); Turina, S.; Ivankovic, V. . Faculty of Mechanical Engineering and Naval Architecture)

    1993-01-01

    Analytical procedure for the quantitative determination of Mg in Al-alloys using ion-exchange thin layer chromatography is described. Chromatographic plates were coated with Amberlite IRP-69 (strong-acid cation exchanger in H[sup +]-form) mixed in different ratios with microcrystalline cellulose. Solutions of HCl and HNO[sub 3] respectively, in the concentration range from 0.5-2.0 mol dm[sup [minus]3] were used as developers. Chromatograms were visualized by spraying with ethanolic solution of 8-hydroxyquinoline and spots were scanned using Camag Turner Fluorometer 111. The optical separation was obtained on TLC plates containing 23% of ion-exchanger (particle size < 60 [mu]m) and by eluting with 1.25 M HCl. R[sub F] (Al) = 0.12, R[sub F](Mg) = 0.41.

  5. Fraunhofer line-dept sensing applied to water

    NASA Technical Reports Server (NTRS)

    Stoertz, G. E.

    1969-01-01

    An experimental Fraunhofer line discriminator is basically an airborne fluorometer, capable of quantitatively measuring the concentration of fluorescent substances dissolved in water. It must be calibrated against standards and supplemented by ground-truth data on turbidity and on approximate vertical distribution of the fluorescent substance. Quantitative use requires that it be known in advance what substance is the source of the luminescence emission; qualitative sensing, or detection of luminescence is also possible. The two approaches are fundamentally different, having different purposes, different applications, and different instruments. When used for sensing of Rhodamine WT dye in coastal waters and estuaries, the FLD is sensing in the spectral region permitting nearly maximum depth of light penetration.

  6. Spectral and Temporal Laser Fluorescence Analysis Such as for Natural Aquatic Environments

    NASA Technical Reports Server (NTRS)

    Chekalyuk, Alexander (Inventor)

    2015-01-01

    An Advanced Laser Fluorometer (ALF) can combine spectrally and temporally resolved measurements of laser-stimulated emission (LSE) for characterization of dissolved and particulate matter, including fluorescence constituents, in liquids. Spectral deconvolution (SDC) analysis of LSE spectral measurements can accurately retrieve information about individual fluorescent bands, such as can be attributed to chlorophyll-a (Chl-a), phycobiliprotein (PBP) pigments, or chromophoric dissolved organic matter (CDOM), among others. Improved physiological assessments of photosynthesizing organisms can use SDC analysis and temporal LSE measurements to assess variable fluorescence corrected for SDC-retrieved background fluorescence. Fluorescence assessments of Chl-a concentration based on LSE spectral measurements can be improved using photo-physiological information from temporal measurements. Quantitative assessments of PBP pigments, CDOM, and other fluorescent constituents, as well as basic structural characterizations of photosynthesizing populations, can be performed using SDC analysis of LSE spectral measurements.

  7. [Effect of dibromothymoquinone on chlorophyll a fluorescence in Chlamydomonas reinhardtii cells incubated in complete or sulfur-depleted medium].

    PubMed

    Volgusheva, A A; Kukarskikh, G P; Antal, T K; Lavrukhina, O G; Krendeleva, T E; Rubin, A B

    2008-01-01

    The influence of dibromothymoquinone on chlorophyll fluorescence was studied in Chlamydomonas reinhardtii cells using PAM and PEA fluorometers. The reagent affected differently control cells incubated in complete medium and S-starved cells. Thus, the fluorescence yield in the control essentially increased in the presence of dibromothymoquinone, which can be due to the inactivation of light-harvesting complex II protein kinase, followed by the suppression of membrane transition from high-fluorescence state 1 to low-fluorescence state 2. On the contrary, S-starved cells with membranes in state 2 showed a lower fluorescence yield in the presence of dibromothymoquinone than without it. The JIP test of OJIP fluorescence transients suggests that dibromothymoquinone inhibits both light-harvesting complex II kinase and photosynthetic electron transport when added to control, while in starved cells, it acts predominantly as an electron acceptor.

  8. Spectrophotometric and colorimetric determination of protein concentration.

    PubMed

    Simonian, Michael H; Smith, John A

    2006-11-01

    This unit describes spectrophotometric and colorimetric methods for measuring the concentration of a sample protein in solution. Absorbance measurement at 280 nm is used to calculate protein concentration by comparison with a standard curve or published absorptivity values for that protein. An alternate protocol uses absorbance at 205 nm to calculate the protein concentration. Both methods can be used to quantitate total protein in crude lysates and purified or partially purified protein. Use of a spectrofluorometer or a filter fluorometer to measure the intrinsic fluorescence emission of a sample solution is also described. The measurement is compared with the emissions from standard solutions to determine the concentration of purified protein. The Bradford colorimetric method, based upon binding of the dye Coomassie brilliant blue to an unknown protein, is also presented, as is the Lowry method, which measures colorimetric reaction of tyrosyl residues in an unknown.

  9. Optimisation of cell-based assays for medium throughput screening of oxidative stress.

    PubMed

    Lautraite, S; Bigot-Lasserre, D; Bars, R; Carmichael, N

    2003-04-01

    Identification and development of cell-based assays adapted to medium throughput screening requirements is important when screening chemicals for their potential toxic properties. We describe here rapid fluorometer-based and spectrophotometer-based microplate assays which allow for the evaluation of oxidative stress in hepatocyte cell cultures by measurement of three markers: production of hydroperoxide assessed by the DCFH-DA probe, cellular antioxidant status by measurement of reduced glutathione and glutathione peroxidase activity and cytotoxicity and mitochondrial damage by evaluation of the mitochondrial transmembrane potential with rhodamine 123 fluorescent dye. The assays described here are rapid, simple and inexpensive, which are desirable when setting up screening assays. This system should be useful in selecting candidate compounds during the pre-development phase of agrochemicals or pharmaceuticals. It should also be of interest for retrospective and explanatory studies of mechanisms underlying toxicity observed in vivo.

  10. Fluorescence dynamics of biological systems using synchrotron radiation

    SciTech Connect

    Gratton, E.; Mantulin, W.W.; Weber, G.; Royer, C.A.; Jameson, D.M.; Reininger, R.; Hansen, R.

    1996-09-01

    A beamline for time-resolved fluorescence spectroscopy of biological systems is under construction at the Synchrotron Radiation Center. The fluorometer, operating in the frequency domain, will take advantage of the time structure of the synchrotron radiation light pulses to determine fluorescence lifetimes. Using frequency-domain techniques, the instrument can achieve an ultimate time resolution on the order of picoseconds. Preliminary experiments have shown that reducing the intensity of one of the fifteen electron bunches in the storage ring allows measurement of harmonic frequencies equivalent to the single-bunch mode. This mode of operation of the synchrotron significantly extends the range of lifetimes that can be measured. The wavelength range (encompassing the visible and ultraviolet), the range of measurable lifetimes, and the stability and reproducibility of the storage ring pulses should make this beamline a versatile tool for the investigation of the complex fluorescence decay of biological systems. {copyright} {ital 1996 American Institute of Physics.}

  11. Loop-mediated isothermal amplification (LAMP) assay-A rapid detection tool for identifying red fox (Vulpes vulpes) DNA in the carcasses of harbour porpoises (Phocoena phocoena).

    PubMed

    Heers, Teresa; van Neer, Abbo; Becker, André; Grilo, Miguel Luca; Siebert, Ursula; Abdulmawjood, Amir

    2017-01-01

    Carcasses of wild animals are often visited by different scavengers. However, determining which scavenger caused certain types of bite marks is particularly difficult and knowledge thereof is lacking. Therefore, a loop-mediated isothermal amplification (LAMP) assay (target sequence cytochrome b) was developed to detect red fox DNA in carcasses of harbour porpoises. The MSwab™ method for direct testing without prior DNA isolation was validated. As a detection device, the portable real-time fluorometer Genie® II was used, which yields rapid results and can be used in field studies without huge laboratory equipment. In addition to in vitro evaluation and validation, a stranded and scavenged harbour porpoise carcass was successfully examined for red fox DNA residues. The developed LAMP method is a valuable diagnostic tool for confirming presumable red fox bite wounds in harbour porpoises without further DNA isolation steps.

  12. Loop-mediated isothermal amplification (LAMP) assay—A rapid detection tool for identifying red fox (Vulpes vulpes) DNA in the carcasses of harbour porpoises (Phocoena phocoena)

    PubMed Central

    Heers, Teresa; van Neer, Abbo; Becker, André; Grilo, Miguel Luca; Siebert, Ursula

    2017-01-01

    Carcasses of wild animals are often visited by different scavengers. However, determining which scavenger caused certain types of bite marks is particularly difficult and knowledge thereof is lacking. Therefore, a loop-mediated isothermal amplification (LAMP) assay (target sequence cytochrome b) was developed to detect red fox DNA in carcasses of harbour porpoises. The MSwab™ method for direct testing without prior DNA isolation was validated. As a detection device, the portable real-time fluorometer Genie® II was used, which yields rapid results and can be used in field studies without huge laboratory equipment. In addition to in vitro evaluation and validation, a stranded and scavenged harbour porpoise carcass was successfully examined for red fox DNA residues. The developed LAMP method is a valuable diagnostic tool for confirming presumable red fox bite wounds in harbour porpoises without further DNA isolation steps. PMID:28863185

  13. Portable flow immunosensor for detecting drugs and explosives

    NASA Astrophysics Data System (ADS)

    Kusterbeck, Anne W.; Gauger, Paul R.; Charles, Paul T.

    1997-02-01

    To assist in airport surveillance efforts, a biosensor based on antibody recognition of individual explosives and drugs has been developed at the Naval Research Laboratory. Analysis of samples containing ng/mL levels of the material are completed in under one minute. Immunoassays for the explosives and the five major drugs of abuse are currently available. The intrinsic nature of antigen-antibody binding also provides the unit with an inherently high degree of selectivity. A portable version of the biosensor that can be run by non-technical personnel is also being engineered. The device, including pumps and fluorometer, will be housed on a modified PCMCIA cartridge fitted into a laptop computer. To run assays, a disposable coupon containing the antibody/fluorescent-antigen complex is inserted into the unit and samples are introduced via a sampling port. Results can be viewed in real time or stored on the computer for later data retrieval and analysis.

  14. Using Fluorophore-labeled Oligonucleotides to Measure Affinities of Protein-DNA Interactions

    PubMed Central

    Anderson, Brian J.; Larkin, Chris; Guja, Kip; Schildbach, Joel F.

    2011-01-01

    Changes in fluorescence emission intensity and anisotropy can reflect changes in the environment and molecular motion of a fluorophore. Researchers can capitalize on these characteristics to assess the affinity and specificity of DNA-binding proteins using fluorophore-labeled oligonucleotides. While there are many advantages to measuring binding using fluorescent oligonucleotides, there are also some distinct disadvantages. Here we describe some of the relevant issues for the novice, illustrating key points using data collected with the F plasmid relaxase domain and a variety of labeled oligonucleotides. Topics include selection of a fluorophore, experimental design using a fluorometer equipped with an automatic titrating unit, and analysis of direct binding and competition assays. PMID:19152864

  15. Combined effects of graphene oxide and Cd on the photosynthetic capacity and survival of Microcystis aeruginosa.

    PubMed

    Tang, Yulin; Tian, Jinglin; Li, Shuyan; Xue, Chonghua; Xue, Zhehua; Yin, Daqiang; Yu, Shuili

    2015-11-01

    In this work, the combined effects of graphene oxide (GO) and Cd(2+) solution on Microcystis aeruginosa were investigated. Chlorophyll fluorescence parameters were measured by a pulse-amplitude modulated fluorometer. GO at low concentrations exhibited no significant toxicity. The presence of GO at low concentrations significantly enhanced Cd(2+) toxicity as the 96 h half maximal effective concentration of the Cd(2+) reduced from 0.51 ± 0.01 to 0.474 ± 0.01 mg/L. However, concentrations of GO above 5mg/L did not significantly increase the toxicity of the Cd(2+)/GO system. Observations through scanning and transmission electron microscopy revealed that GO, with Cd(2+), easily attached to and entered into the algae. Reactive oxygen species and malondialdehyde were measured to explain the toxicity mechanism. The photosynthetic parameters were useful in measuring the combined toxicity of the nanoparticles and heavy metals. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Enzymic Assay of 10−7 to 10−14 Moles of Sucrose in Plant Tissues 1

    PubMed Central

    Jones, Michael G. K.; Outlaw, William H.; Lowry, Oliver H.

    1977-01-01

    Procedures are described for measuring sucrose in plant extracts or freeze-dried tissue in the range between 10−7 and 10−14 moles. The method is based on the destruction of pre-existing glucose and fructose, followed by the hydrolysis of sucrose and reduction of NADP+ by a series of coupled enzymic reactions. Depending on the sensitivity required, the NADPH is determined directly with a spectrophotometer or a fluorometer, or is amplified as much as 30,000 times before fluorometric assay. The procedures suggested for the macro level are simpler than current methods, and those suggested for microanalysis are several orders of magnitude more sensitive. With this technique, single palisade parenchyma cells and single spongy parenchyma cells of Vicia faba leaflets were each found to contain about 2.2 pmoles of sucrose. Images PMID:16660097

  17. DNA detection using water-soluble conjugated polymers and peptide nucleic acid probes

    PubMed Central

    Gaylord, Brent S.; Heeger, Alan J.; Bazan, Guillermo C.

    2002-01-01

    The light-harvesting properties of cationic conjugated polymers are used to sensitize the emission of a dye on a specific peptide nucleic acid (PNA) sequence for the purpose of homogeneous, “real-time” DNA detection. Signal transduction is controlled by hybridization of the neutral PNA probe and the negative DNA target. Electrostatic interactions bring the hybrid complex and cationic polymer within distances required for Förster energy transfer. Conjugated polymer excitation provides fluorescein emission >25 times higher than that obtained by exciting the dye, allowing detection of target DNA at concentrations of 10 pM with a standard fluorometer. A simple and highly sensitive assay with optical amplification that uses the improved hybridization behavior of PNA/DNA complexes is thus demonstrated. PMID:12167673

  18. Monitoring copper toxicity in natural phytoplankton assemblages: application of Fast Repetition Rate fluorometry.

    PubMed

    Pérez, Patricia; Beiras, Ricardo; Fernández, Emilio

    2010-09-01

    Four experiments were conducted with natural coastal phytoplankton assemblages exposed to [Cu] within the range 5-80 microg L(-1). The effect of Cu on several biological variables such as chlorophyll a concentration, particle size distribution, O2-production and fluorescence variables recorded by a Fast Repetition Rate fluorometer was monitored during 72 h. Variable fluorescence (Fv) was the most sensitive and rapid among all the variables tested. This work contributes to reinforce the use of fluorescence endpoints in ecotoxicological studies by proving their ecological relevance through relationships found between fluorescence and population-level responses as growth rate and gross O2 production. The lowest calculated EC10 was 2.65 microg L(-1), concentration commonly exceeded in polluted waters.

  19. Studying Gene Expression: Database Searches and Promoter Fusions to Investigate Transcriptional Regulation in Bacteria†

    PubMed Central

    Martinez-Vaz, Betsy M.; Makarevitch, Irina; Stensland, Shane

    2010-01-01

    A laboratory project was designed to illustrate how to search biological databases and utilize the information provided by these resources to investigate transcriptional regulation in Escherichia coli. The students searched several databases (NCBI Genomes, RegulonDB and EcoCyc) to learn about gene function, regulation, and the organization of transcriptional units. A fluorometer and GFP promoter fusions were used to obtain fluorescence data and measure changes in transcriptional activity. The class designed and performed experiments to investigate the regulation of genes necessary for biosynthesis of amino acids and how expression is affected by environmental signals and transcriptional regulators. Assessment data showed that this activity enhanced students’ knowledge of databases, reporter genes and transcriptional regulation. PMID:23653697

  20. Gigahertz Frequency-Domain Fluorometry: Applications To Picosecond Processes And Future Developments

    NASA Astrophysics Data System (ADS)

    Lakowicz, Joseph R.; Laczko, Gabor; Gryczynski, Ignacy; Cherek, Henryk; Wiczk, Wieslaw

    1988-06-01

    We describe our frequency-domain fluorometer which allows phase angle and demodulation measurements from 8 MHz to 2 GHz. This instrument using the harmonic content of a 7.59 MHz train of 5 ps pulses as the modulated excitation source. The detector is a microchannel plate PMT (R1564U), whose bandwidth extends to 2 GHz. Using this instrument we examined rapid rotational motions of indole in low viscosity solvents. To date, the shortest correlation time we have determined was 7 ps, for indole in methanol at 80°C. For indole in cyclohexane at 20°C we were able to resolve two rotational correlation times of 17 and 73 ps. It now appears that the frequency range can be extended to 8 GHz, so still faster processes should be observable.

  1. Biochemical Applications Of Frequency-Domain Fluorometry; Determination Of Time-Resolved Anisotropies And Emission Spectra

    NASA Astrophysics Data System (ADS)

    Lakowicz, Joseph R.; Gryczynski, Ignazy; Cherek, Henryh; Laczko, Gabor; Joshi, Nanda

    1987-01-01

    Measurements of time-resolved fluorescence are often used for studies of biological macromolecules. Such measurements are usually performed in the time-domain, by measurement of the time-dependent emission following pulsed excitation. It has recently become possible to measure the frequency-response of the emission to intensity modulated light, over a wide range of modulation frequencies. We used frequency-domain fluorometers which operates from 1 to 220 MHz, and more recently to 2000 MHz. The frequency-domain data provide excellent resolution of time-dependent spectral parameters. It is now possible to resolve closely spaced fluorescence lifetimes, to determine multi-exponential decays of anisotropy and to determine time-resolved emission spectra of samples which display time-dependent spectral shifts. In this article we show representative results on tryptophan fluorescence from proteins and for protein-bound fluorophores.

  2. How many organisms are in ballast water discharge? A framework for validating and selecting compliance monitoring tools.

    PubMed

    Drake, Lisa A; Tamburri, Mario N; First, Matthew R; Smith, G Jason; Johengen, Thomas H

    2014-09-15

    As regulations governing the discharge of living organisms in ships' ballast water enter into force, tools to rapidly and easily measure compliance with the discharge standards will be essential. To assess, validate, and select compliance tools, a framework-consisting of three parts-is presented: proof-of-concept, validation and verification, and final selection stages. Next, a case study describing the proof-of-concept stage is discussed. Specifically, variable fluorescence was evaluated as an approach for determining compliance with the discharge standard for living organisms ⩾10 μm and <50 μm (typically protists). Preliminary laboratory experiments were conducted, which were followed by an expert workshop to gauge the feasibility of this approach and propose hypothetical thresholds indicating when the discharge standard is undoubtedly exceeded. Subsequently, field trials were conducted to assess this approach and recommended thresholds. All results were favorable, indicating the validation and verification stages are merited to further evaluate fluorometers as compliance monitoring tools.

  3. A microfluidic nano-biosensor for the detection of pathogenic Salmonella.

    PubMed

    Kim, Giyoung; Moon, Ji-Hea; Moh, Chang-Yeon; Lim, Jong-guk

    2015-05-15

    Rapid detection of pathogenic Salmonella in food products is extremely important for protecting the public from salmonellosis. The objective of the present study was to explore the feasibility of using a microfluidic nano-biosensor to rapidly detect pathogenic Salmonella. Quantum dot nanoparticles were used to detect Salmonella cells. For selective detection of Salmonella, anti-Salmonella polyclonal antibodies were covalently immobilized onto the quantum dot surface. To separate and concentrate the cells from the sample, superparamagnetic particles and a microfluidic chip were used. A portable fluorometer was developed to measure the fluorescence signal from the quantum dot nanoparticles attached to Salmonella in the samples. The sensitivity for detection of pathogenic Salmonella was evaluated using serially diluted Salmonella Typhimurium in borate buffer and chicken extract. The fluorescence response of the nano-biosensor increased with increasing cell concentration. The detection limit of the sensor was 10(3) CFU/mL Salmonella in both borate buffer and food extract.

  4. Pink Water: Surfzone Dye Measurements at Huntington Beach, CA.

    NASA Astrophysics Data System (ADS)

    Clark, D. B.; Woodward, B.; Boyd, W. A.; Feddersen, F.; Guza, R. T.

    2006-12-01

    Mixing in the surfzone controls the dispersal and transport of pollution, bacteria, and other tracers near the shoreline. However, the difficulty of measuring tracer concentrations in breaking waves has limited studies of surfzone mixing. Surfzone turbulent length scales range from sub-meter in the bores of broken waves to 100's of meters in shear waves, and the mechanisms primarily responsible for tracer dispersion are unclear. Dye tracer experiments will be part of HB06, a multi-institutional study at Huntington Beach, California in Fall 2006. Waves, currents and temperature will be measured simultaneously at seven cross-shore and four alongshore locations in the surfzone. Fluorescent Rhodamine-WT dye will be measured using in-situ fluorometers, bottle samples, and a novel GPS tracked jetski platform. Onboard, flow-through fluorescence and turbidity measurements will be made 20 cm below the surface at an effective sample rate of 0.5 Hz, as the jetski crosses the surfzone at about 4 m/s. Five fixed fluorometers on the cross-shore transect will record dye fluorescence and turbidity approximately 50 cm from the bottom, and shoreline bottle samples will determine dye concentration in water too shallow for the jetski. Measured in-situ Rhodamine-WT fluorescence is reduced by the presence of sand and bubbles. Laboratory tests simulating average surfzone conditions have found that this corresponds to a 10-20% reduction in measured dye concentration. While this creates noise in the signal, dye concentrations usually vary over 1-2 orders of magnitude and observations are still useable. Both patch and continuous releases of dye will be used to infer dispersion statistics, and preliminary results will be reported. This research was supported by the California Coastal Conservancy, Sea Grant, and ONR.

  5. Quantifying diatom silicification with the fluorescent dye, PDMPO.

    PubMed

    McNair, Heather M; Brzezinski, Mark A; Krause, Jeffrey W

    2015-10-01

    Diatoms require silicic acid to construct ornately detailed cell walls called frustules. The growth and geographic distribution of diatoms is often controlled by the availability of silicic acid. Analytical methods exist to assess diatom community biogenic silica (bSiO2) production, but partitioning production among taxa has been largely qualitative. We present a method for the quantitative analysis of taxa-specific silica production through labeling diatoms with the fluorescent dye PDMPO [2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)methoxy)phenyl)oxazole]. To make PDMPO a quantitative tool: diatom frustules were solubilized to assess the total diatom community incorporation by quantitation of PDMPO fluorescence using a fluorometer, and laser confocal microscopy was used to quantify the fluorescence of PDMPO in single diatom cells. We created a fluorescence standard to intercalibrate the raw fluorescence signals of the fluorometer and microscope and to determine the fluorescence per mole of PDMPO. PDMPO incorporation was converted to silica production using diatom bSiO2:PDMPO incorporation ratios which varied systematically with silicic acid concentration. Above 3 μM Si(OH)4, bSiO2:PDMPO was constant and PDMPO incorporation was converted to silica production using a mole ratio of 2,916 as determined from cultures. Below 3 μM, the ratio was a linear function of [Si(OH)4] (bSiO2:PDMPO = 912.6 × [Si(OH)4]), as determined using data from two oceanographic cruises. Field evaluation of the method showed that total community PDMPO incorporation generally agreed to within 30% of radioisotope-determined silica production. This PDMPO method has the potential to be a powerful tool for understanding physiology, silicification and resource competition among diatom taxa.

  6. Real-time measurement of platelet shape change by light scattering under riboflavin and ultraviolet light treatment.

    PubMed

    Terada, Chikahiro; Shiba, Masayuki; Satake, Masahiro; Tadokoro, Kenji

    2016-03-01

    The adoption of pathogen reduction technologies (PRTs) is considered for the implementation of safer platelet (PLT) transfusion. However, the effects of PRT treatment including irradiation with ultraviolet (UV) light on PLT shape have not yet been fully clarified. Leukoreduced PLT concentrates (PCs) were treated with riboflavin and UV light (Mirasol PRT, TerumoBCT). PLT shape and adenosine diphosphate (ADP)-induced shape change were evaluated by a light scattering method where the amplitude of the scattered signal intensity was measured as the indicator of the proportion of discoid PLTs. Using a modified fluorometer, the real-time effects of different wavelengths of UV light on PLT shape were examined over the range of 300 to 360 nm at the same dose. The proportion of discoid PLTs in the Mirasol PRT-treated PCs decreased immediately after treatment. The difference in the proportion between PRT-treated and untreated PLTs became larger with storage. Although this modification correlated significantly with the pH decrease and P-selectin expression, the Mirasol PRT-treated PLTs retained sufficient ability to undergo an ADP-induced shape change. In the study using the modified fluorometer, the proportion of discoid PLTs significantly decreased with the wavelength (< 320 nm) of irradiated UV light. Mirasol PRT treatment of PCs decreases the proportion of discoid PLTs, which seemed to be caused by the irradiation with UV light of short wavelengths (< 320 nm), not that of long wavelengths (≥ 320 nm) in the Mirasol PRT system. Modification of UV light wavelength may improve the quality of PRT-treated PCs. © 2015 AABB.

  7. Combined processing and mutual interpretation of radiometry and fluorometry from autonomous profiling Bio-Argo floats: 2. Colored dissolved organic matter absorption retrieval

    NASA Astrophysics Data System (ADS)

    Xing, Xiaogang; Morel, André; Claustre, Hervé; D'Ortenzio, Fabrizio; Poteau, Antoine

    2012-04-01

    Eight autonomous profiling "Bio-Argo" floats were deployed offshore during about 2 years (2008-2010) in Pacific, Atlantic, and Mediterranean zones. They were equipped with miniaturized bio-optical sensors, namely a radiometer measuring within the upper layer the downward irradiance at 412, 490, and 555 nm, and two fluorometers for detection of chlorophyll-a (Chla) and colored dissolved organic matter (CDOM; profiles from 400 m to surface). A first study dealt with the interpretation of the Chla fluorescence signal in terms of concentration, using for this purpose the diffuse attenuation coefficient for irradiance at 490 nm, Kd(490), taken as a proxy for the Chla absorption. The present study examines the possibility of similarly using the Kd(412) values combined with retrieved Chla profiles to convert the CDOM fluorometric qualitative information into a CDOM absorption coefficient (ay). The rationale is to take advantage of the fact that Kd is more sensitive to CDOM presence at 412 nm than at 490 nm. A validation of this method is tested through its application to field data, collected from a ship over a wide range of trophic conditions (Biogeochemistry and Optics South Pacific Experiment (BIOSOPE) cruise); these data include both in situ fluorescence profiles and CDOM absorption as measured on discrete samples. In addition, near-surface ay values retrieved from the floats agree with those derivable from ocean color imagery (Moderate Resolution Imaging Spectroradiometer (MODIS-A)). The low sensitivity of commercially available CDOM fluorometers presently raises difficulties when applying this technique to open ocean waters. It was nevertheless possible to derive from the floats records meaningful time series of CDOM vertical distribution.

  8. A new minimum fluorescence parameter, as generated using pulse frequency modulation, compared with pulse amplitude modulation: Falpha versus Fo.

    PubMed

    Wright, A Harrison; DeLong, John M; Franklin, Jeffrey L; Lada, Rajasekaran R; Prange, Robert K

    2008-09-01

    The minimum fluorescence parameter (Falpha), generated using the new pulse frequency modulation (PFM) technology, was compared with the minimum fluorescence parameter (Fo), generated by pulse amplitude modulation (PAM), in response to a reversible low-oxygen stress in 'Honeycrisp'trade mark (HC) apples (Malus domestica) and an irreversible osmotic stress induced by water loss in two grape (Vitis spp.) cultivars ('L'Acadie' (LAc) and 'Thompson Seedless' (TS)). The minimum fluorescence values produced by both fluorometer types in response to a reversible low-oxygen stress in apples were indistinguishable: both Fo and Falpha increased when O2 levels were lowered below the anaerobic compensation point (ACP); when gas levels returned to normoxia both parameters dipped below, then returned to, the original fluorescence baseline. The two parameters also responded similarly to the irreversible osmotic stress in grapes: in both cultivars, Falpha and Fo first decreased before reaching an inflection point at approximately 20% mass loss and then increased towards a second inflection point. However, the two parameters were not analogous under the irreversible osmotic stress; most notably, the relative Falpha values appeared to be lower than Fo during the later stages of dehydration. This was likely due to the influence of the Fm parameter and an overestimation of Falpha when measuring the fluorescence from healthy and responsive chloroplasts as found in grapes experiencing minimal water loss, but not in grapes undergoing moderate to severe dehydration. An examination of the data during a typical PFM scan reveals this fluorometer system may yield new fluorescence information with interesting biological applications.

  9. Quantifying diatom silicification with the fluorescent dye, PDMPO

    PubMed Central

    Brzezinski, Mark A.; Krause, Jeffrey W.

    2015-01-01

    Diatoms require silicic acid to construct ornately detailed cell walls called frustules. The growth and geographic distribution of diatoms is often controlled by the availability of silicic acid. Analytical methods exist to assess diatom community biogenic silica (bSiO2) production, but partitioning production among taxa has been largely qualitative. We present a method for the quantitative analysis of taxa-specific silica production through labeling diatoms with the fluorescent dye PDMPO [2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)methoxy)phenyl)oxazole]. To make PDMPO a quantitative tool: diatom frustules were solubilized to assess the total diatom community incorporation by quantitation of PDMPO fluorescence using a fluorometer, and laser confocal microscopy was used to quantify the fluorescence of PDMPO in single diatom cells. We created a fluorescence standard to intercalibrate the raw fluorescence signals of the fluorometer and microscope and to determine the fluorescence per mole of PDMPO. PDMPO incorporation was converted to silica production using diatom bSiO2:PDMPO incorporation ratios which varied systematically with silicic acid concentration. Above 3 μM Si(OH)4, bSiO2:PDMPO was constant and PDMPO incorporation was converted to silica production using a mole ratio of 2,916 as determined from cultures. Below 3 μM, the ratio was a linear function of [Si(OH)4] (bSiO2:PDMPO = 912.6 × [Si(OH)4]), as determined using data from two oceanographic cruises. Field evaluation of the method showed that total community PDMPO incorporation generally agreed to within 30% of radioisotope-determined silica production. This PDMPO method has the potential to be a powerful tool for understanding physiology, silicification and resource competition among diatom taxa. PMID:26793033

  10. Real-time Monitoring of Dissolved Organic Matter (DOM) Amount, Composition, Source and Reactivity Using Fluorescence Spectroscopy: Applications for Drinking Water Quality

    NASA Astrophysics Data System (ADS)

    Kraus, T. E.; Saraceno, J.; Downing, B. D.; Goldman, J. H.; Carpenter, K. D.; McGhee, G.; Bergamaschi, B. A.

    2010-12-01

    There is growing interest in the use of in situ, continuous fluorescence spectroscopy as a proxy for dissolved organic carbon (DOC) concentration. To date, in situ fluorometers designed to estimate DOC concentration are single wavelength sensors centered near the excitation/emission (ex/em) pair 370/460 nm. Additional information about dissolved organic matter (DOM) composition has only been obtainable from benchtop fluorometers that provide multi-spectral data. Changes in DOM composition are important as they provide insight into DOM source (e.g. terrestrial, algal, wastewater) and reactivity. Recent advances in sensor technology make it possible to build in situ instruments for measuring multiple fluorescence ex/em pairs, including pairs with excitations in the lower “deep UV” region (e.g. 270/340 nm) associated with fresher and more labile DOM pools. The deployment of multi-spectral sensors will provide real-time continuous data showing not only changes in DOM concentration, but also changes in composition. This information is particularly pertinent to drinking water utilities because a fraction of DOM reacts upon disinfection (e.g. chlorination and ozonation) to form toxic disinfection byproducts (DBPs) which are regulated by the EPA. To test this application, we designed a multi-wavelength sensor that will measure three ex/em pairs (370/470, 370/520 and 270/340 nm) for deployment near a drinking water intake on the Clackamas River in Oregon. Comparison of the continuous data with discrete sample data indicates these tools can track both quantitative and qualitative changes in the DOM pool. The availability of this type of continuous data in real time could enable utilities to minimize the formation of DBPs by continuously optimizing treatment plant operations in response to changes in source water. In addition, collection of high-frequency data will improve understanding of watershed DOM dynamics and help identify sources of DOM and DBP precursors, thereby

  11. An integrated portable hand-held analyser for real-time isothermal nucleic acid amplification.

    PubMed

    Smith, Matthew C; Steimle, George; Ivanov, Stan; Holly, Mark; Fries, David P

    2007-08-29

    A compact hand-held heated fluorometric instrument for performing real-time isothermal nucleic acid amplification and detection is described. The optoelectronic instrument combines a Printed Circuit Board/Micro Electro Mechanical Systems (PCB/MEMS) reaction detection/chamber containing an integrated resistive heater with attached miniature LED light source and photo-detector and a disposable glass waveguide capillary to enable a mini-fluorometer. The fluorometer is fabricated and assembled in planar geometry, rolled into a tubular format and packaged with custom control electronics to form the hand-held reactor. Positive or negative results for each reaction are displayed to the user using an LED interface. Reaction data is stored in FLASH memory for retrieval via an in-built USB connection. Operating on one disposable 3 V lithium battery >12, 60 min reactions can be performed. Maximum dimensions of the system are 150 mm (h) x 48 mm (d) x 40 mm (w), the total instrument weight (with battery) is 140 g. The system produces comparable results to laboratory instrumentation when performing a real-time nucleic acid sequence-based amplification (NASBA) reaction, and also displayed comparable precision, accuracy and resolution to laboratory-based real-time nucleic acid amplification instrumentation. A good linear response (R2 = 0.948) to fluorescein gradients ranging from 0.5 to 10 microM was also obtained from the instrument indicating that it may be utilized for other fluorometric assays. This instrument enables an inexpensive, compact approach to in-field genetic screening, providing results comparable to laboratory equipment with rapid user feedback as to the status of the reaction.

  12. Spatial distribution and seasonal variability of chlorophyll-a concentration in the Azov Sea turbid waters by means of remote sensing and continuous fluorescence measurements

    NASA Astrophysics Data System (ADS)

    Saprygin, V. V.

    2011-12-01

    The goal of this study was to apply continuous fluorometric and remote estimation of chlorophyll-a concentration (Cchl) techniques to complex turbid waters of Azov Sea and explore Cchl temporal variation and spatial pattern. Azov Sea is the shallowest sea in the world with maximum depth below 15 m. Its maximum salinity is about 14%; total suspended solids and chlorophyll-a concentrations reach 120 [tex]g m^{-3}[/tex] and 100 [tex]mg m^{-3}[/tex] respectively in Taganrog Bay, daily production varies up to 3.5 [tex]gC_{org} m^{-3}[/tex]. Chlorophyll-a concentrations were measured in 2008-2010 year-round spectrophotometrically, 446 water samples were taken to calibrate fluorometerical and remote sensing data. The highest recorded concentration was 149.3, the lowest - 0.3 [tex]mg m^{-3}[/tex]. Continuous-flow fluorometer was applied in the course of 3 expeditions to Taganrog Bay to measure chlorophyll-a fluorescence (Fchl) each 30 meters along the ship path. Two-cuvette fluorometer was used to discount the influence of dissolved organic matter. Fchl measurements were calibrated and Cchl profiles derieved to estimate Cchl spatial heterogeneity in close scale. Fchl measurements were also made during moorings each 6 seconds to estimate temporal Cchl variability. Recently published algorithm based on reflectance in the red and the near-infrared (NIR) spectral regions was applied to MERIS data for the remote estimation of Cchl. Taking in account fluorometric Cchl spatial heterogeneity estimation, the algorithm for culling the outliers in Cchl fields derived from satellite data was developed. 74 images were processed to Cchl maps and then averaged monthly. Consequently, Cchl spatial distribution and seasonal variability were studied. Spectrophotometric, flourumetric measurements and values obtained by NIR-red algorithm showed strong correlation in turbid Case II waters of Azov Sea. Fluorometric and remote measurements showed high Cchl variations in short and long terms

  13. Global spectral-kinetic analysis of room temperature chlorophyll a fluorescence from light-harvesting antenna mutants of barley.

    PubMed

    Gilmor, A M; Itoh, S; Govindjee

    2000-10-29

    This study presents a novel measurement, and simulation, of the time-resolved room temperature chlorophyll a fluorescence emission spectra from leaves of the barley wild-type and chlorophyll-b-deficient chlorina (clo) f2 and f104 mutants. The primary data were collected with a streak-camera-based picosecond-pulsed fluorometer that simultaneously records the spectral distribution and time dependence of the fluorescence decay. A new global spectral-kinetic analysis programme method, termed the double convolution integral (DCI) method, was developed to convolve the exciting laser pulse shape with a multimodal-distributed decay profile function that is again convolved with the spectral emission band amplitude functions. We report several key results obtained by the simultaneous spectral-kinetic acquisition and DCI methods. First, under conditions of dark-level fluorescence, when photosystem II (PS II) photochemistry is at a maximum at room temperature, both the clo f2 and clo f104 mutants exhibit very similar PS II spectral-decay contours as the wild-type (wt), with the main band centred around 685 nm. Second, dark-level fluorescence is strongly influenced beyond 700 nm by broad emission bands from PS I, and its associated antennae proteins, which exhibit much more rapid decay kinetics and strong integrated amplitudes. In particular a 705-720 nm band is present in all three samples, with a 710 nm band predominating in the clo f2 leaves. When the PS II photochemistry becomes inhibited, maximizing the fluorescence yield, both the clo f104 mutant and the wt exhibit lifetime increases for their major distribution modes from the minimal 205-500 ps range to the maximal 1500-2500 ps range for both the 685 nm and 740 nm bands. The clo f2 mutant, however, exhibits several unique spectral-kinetic properties, attributed to its unique PS I antennae and thylakoid structure, indicating changes in both PS II fluorescence reabsorption and PS II to PS I energy transfer pathways

  14. FRET-Aptamer Assays for Bone Marker Assessment, C-Telopeptide, Creatinine, and Vitamin D

    NASA Technical Reports Server (NTRS)

    Bruno, John G.

    2013-01-01

    Astronauts lose 1.0 to 1.5% of their bone mass per month on long-duration spaceflights. NASA wishes to monitor the bone loss onboard spacecraft to develop nutritional and exercise countermeasures, and make adjustments during long space missions. On Earth, the same technology could be used to monitor osteoporosis and its therapy. Aptamers bind to targets against which they are developed, much like antibodies. However, aptamers do not require animal hosts or cell culture and are therefore easier, faster, and less expensive to produce. In addition, aptamers sometimes exhibit greater affinity and specificity vs. comparable antibodies. In this work, fluorescent dyes and quenchers were added to the aptamers to enable pushbutton, one-step, bind-and-detect fluorescence resonance energy transfer (FRET) assays or tests that can be freeze-dried, rehydrated with body fluids, and used to quantitate bone loss of vitamin D levels with a handheld fluorometer in the spacecraft environment. This work generated specific, rapid, one-step FRET assays for the bone loss marker C-telopeptide (CTx) when extracted from urine, creatinine from urine, and vitamin D congeners in diluted serum. The assays were quantified in nanograms/mL using a handheld fluorometer connected to a laptop computer to convert the raw fluorescence values into concentrations of each analyte according to linear standard curves. DNA aptamers were selected and amplified for several rounds against a 26- amino acid form of CTx, creatinine, and vitamin D. The commonalities between loop structures were studied, and several common loop structures were converted into aptamer beacons with a fluorophore and quencher on each end. In theory, when the aptamer beacon binds its cognate target (CTx bone peptide, creatinine, or vitamin D), it is forced open and no longer quenched, so it gives off fluorescent light (when excited) in proportion to the amount of target present in a sample. This proportional increase in fluorescence is

  15. A rapid diagnostic test and mobile "lab in a suitcase" platform for detecting Ceratocystis spp. responsible for Rapid ‘Ōhi‘a Death

    USGS Publications Warehouse

    Atkinson, Carter T.; Watcher-Weatherwax, William; Roy, Kylle; Heller, Wade P; Keith, Lisa

    2017-01-01

    We describe a field compatible molecular diagnostic test for two new species of Ceratocystis that infect `ōhi`a (Metrosideros polymorpha) and cause the disease commonly known as Rapid `Ōhi`a Death. The diagnostic is based on amplification of a DNA locus within the internal transcribed spacer region that separates fungal 5.8S ribosomal genes. The assay uses forward and reverse primers, recombinase polymerase, and a fluorescent probe that allows isothermal (40oC) amplification and simultaneous quantification of a 115 base pair product with a battery operated fluorometer. DNA extractions are field compatible and can be done by heating wood drill shavings to 100oC in Instagene® solution containing Chelex® resin to bind potential amplification inhibitors. The initial heat treatment is followed by a short bead beating step with steel ball bearings and zirconium beads to release DNA. DNA is subsequently purified with a magnetic bead based extraction method that does not require silica columns or centrifugation. The assay is designed around a portable “lab-in-a-suitcase” platform that includes a portable fluorometer, miniature centrifuge, and heat block that operate off either 120V AC power sources or a 12 volt battery with a portable inverter, a magnetic rack designed for 1.5 ml tubes and magnetic bead DNA purification, pipettes and consumable reagents and tubes. The entire assay from DNA extraction to results can be performed in less than 90 minutes on up to six independent samples plus a positive and negative control. Sensitivity based on suspensions of Ceratocystis endoconidia (spores) that were added to wood shavings and processed under field conditions by Instagene® magnetic bead DNA extraction was up to 163 spores/mg wood for Species A and 55 spores/mg wood for Species B in 95% of replicates as determined by probit analysis. Sensitivity increased 5–10 fold to 19 spores/mg wood for Species A and 9 spores/mg wood for Species B when extractions were

  16. Image stacking approach to increase sensitivity of fluorescence detection using a low cost complementary metal-oxide-semiconductor (CMOS) webcam

    PubMed Central

    Balsam, Joshua; Bruck, Hugh Alan; Kostov, Yordan; Rasooly, Avraham

    2013-01-01

    Optical technologies are important for biological analysis. Current biomedical optical analyses rely on high-cost, high-sensitivity optical detectors such as photomultipliers, avalanched photodiodes or cooled CCD cameras. In contrast, Webcams, mobile phones and other popular consumer electronics use lower-sensitivity, lower-cost optical components such as photodiodes or CMOS sensors. In order for consumer electronics devices, such as webcams, to be useful for biomedical analysis, they must have increased sensitivity. We combined two strategies to increase the sensitivity of CMOS-based fluorescence detector. We captured hundreds of low sensitivity images using a Webcam in video mode, instead of a single image typically used in cooled CCD devices.We then used a computational approach consisting of an image stacking algorithm to remove the noise by combining all of the images into a single image. While video mode is widely used for dynamic scene imaging (e.g. movies or time-lapse photography), it is not used to capture a single static image, which removes noise and increases sensitivity by more than thirty fold. The portable, battery-operated Webcam-based fluorometer system developed here consists of five modules: (1) a low cost CMOS Webcam to monitor light emission, (2) a plate to perform assays, (3) filters and multi-wavelength LED illuminator for fluorophore excitation, (4) a portable computer to acquire and analyze images, and (5) image stacking software for image enhancement. The samples consisted of various concentrations of fluorescein, ranging from 30 μM to 1000 μM, in a 36-well miniature plate. In the single frame mode, the fluorometer's limit-of-detection (LOD) for fluorescein is ∼1000 μM, which is relatively insensitive. However, when used in video mode combined with image stacking enhancement, the LOD is dramatically reduced to 30 μM, sensitivity which is similar to that of state-of-the-art ELISA plate photomultiplier-based readers. Numerous medical

  17. Linkages among runoff, dissolved organic carbon, and the stable oxygen isotope composition of seawater and other water mass indicators in the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Cooper, Lee W.; Benner, Ronald; McClelland, James W.; Peterson, Bruce J.; Holmes, Robert M.; Raymond, Peter A.; Hansell, Dennis A.; Grebmeier, Jacqueline M.; Codispoti, Louis A.

    2005-12-01

    Flow-weighted dissolved organic carbon (DOC) concentrations and δ18O values were determined from major arctic rivers, specifically the Ob, Yenisey, Lena, Kolyma, Mackenzie, and Yukon during 2003-2004. These data were considered in conjunction with marine data for DOC, δ18O values, nutrients, salinity, and fluorometric indicators of DOC obtained during sampling at the shelf-basin boundary of the Chukchi and Beaufort seas. On the basis of these data, freshwater in the sampled marine waters is likely derived from regional sources, such as the Mackenzie, the Bering Strait inflow, and possibly eastern Siberian rivers, including the Kolyma, or the Lena, but not rivers farther west in the Eurasian arctic. Freshwater from melted sea ice is insignificant over annual cycles, although melted sea ice was a locally dominant freshwater component following summer sea-ice retreat in 2002. DOC concentrations were correlated with the runoff fraction, with an apparent meteoric water DOC concentration of 174 ± 1 μM. This is lower than the flow-weighted concentrations measured at river mouths of the five largest Arctic rivers (358 to 917 μM), indicating removal of DOC during transport through estuaries, shelves and in the deep basin. Flow-weighted DOC concentrations in the two largest North American arctic rivers, the Yukon (625 μM) and the Mackenzie (358 μM), are lower than in the three largest Eurasian arctic rivers, the Ob (825 μM), the Yenesey (858 μM), and the Lena (917 μM). A fluorometer responding to chromophoric dissolved organic matter (CDOM) was not correlated with DOC concentrations in Pacific-influenced surface waters unlike previous observations in the Atlantic layer. Nutrient distributions, concentrations, and derived ratios suggest the CDOM fluorometer may be responding to the release of chromophoric materials from shelf sediments. Shipboard incubations of undisturbed sediment cores indicate that sediments on the Bering and Chukchi Sea shelves are a net source

  18. Calibration procedures and first data set of Southern Ocean chlorophyll a profiles collected by elephant seal equipped with a newly developed CTD-fluorescence tags

    NASA Astrophysics Data System (ADS)

    Guinet, C.; Xing, X.; Walker, E.; Monestiez, P.; Marchand, S.; Picard, B.; Jaud, T.; Authier, M.; `Cotté, C.; Dragon, A. C.; Diamond, E.; Antoine, D.; Lovell, P.; Blain, S.; D'Ortenzio, F.; Claustre, H.

    2012-08-01

    In-situ observation of the marine environment has traditionally relied on ship-based platforms. The obvious consequence is that physical and biogeochemical properties have been dramatically undersampled, especially in the remote Southern Ocean (SO). The difficulty in obtaining in situ data represents the major limitations to our understanding, and interpretation of the coupling between physical forcing and the biogeochemical response. Southern elephant seals (Mirounga leonina) equipped with a new generation of oceanographic sensors can measure ocean structure in regions and seasons rarely observed with traditional oceanographic platforms. Over the last few years, seals have allowed for a considerable increase in temperature and salinity profiles from the SO. However we were still lacking information on the spatio-temporal variation of phytoplankton concentration. This information is critical to assess how the biological productivity of the SO, with direct consequences on the amount of CO2 "fixed" by the biological pump, will respond to global warming. In this research program, we use an innovative sampling fluorescence approach to quantify phytoplankton concentration at sea. For the first time, a low energy consumption fluorometer was added to Argos CTD-SRDL tags, and these novel instruments were deployed on 27 southern elephant seals between 25 December 2007 and the 4 February 2011. As many as 3388 fluorescence profiles associated with temperature and salinity measurements were thereby collected from a vast sector of the Southern Indian Ocean. This paper address the calibration issue of the fluorometer before being deployed on elephant seals and present the first results obtained for the Indian Sector of the Southern Ocean. This in situ system is implemented in synergy with satellite ocean colour radiometry. Satellite-derived data is limited to the surface layer and is restricted over the SO by extensive cloud cover. However, with the addition of these new tags

  19. Calibration procedures and first dataset of Southern Ocean chlorophyll a profiles collected by elephant seals equipped with a newly developed CTD-fluorescence tags

    NASA Astrophysics Data System (ADS)

    Guinet, C.; Xing, X.; Walker, E.; Monestiez, P.; Marchand, S.; Picard, B.; Jaud, T.; Authier, M.; Cotté, C.; Dragon, A. C.; Diamond, E.; Antoine, D.; Lovell, P.; Blain, S.; D'Ortenzio, F.; Claustre, H.

    2013-02-01

    In situ observation of the marine environment has traditionally relied on ship-based platforms. The obvious consequence is that physical and biogeochemical properties have been dramatically undersampled, especially in the remote Southern Ocean (SO). The difficulty in obtaining in situ data represents the major limitations to our understanding, and interpretation of the coupling between physical forcing and the biogeochemical response. Southern elephant seals (Mirounga leonina) equipped with a new generation of oceanographic sensors can measure ocean structure in regions and seasons rarely observed with traditional oceanographic platforms. Over the last few years, seals have allowed for a considerable increase in temperature and salinity profiles from the SO, but we were still lacking information on the spatiotemporal variation of phytoplankton concentration. This information is critical to assess how the biological productivity of the SO, with direct consequences on the amount of CO2 "fixed'' by the biological pump, will respond to global warming. In this research programme, we use an innovative sampling fluorescence approach to quantify phytoplankton concentration at sea. For the first time, a low energy consumption fluorometer was added to Argos CTD-SRDL tags, and these novel instruments were deployed on 27 southern elephant seals between 25 December 2007 and the 4 February 2011. As many as 3388 fluorescence profiles associated with temperature and salinity measurements were thereby collected from a vast sector of the Southern Indian Ocean. This paper addresses the calibration issue of the fluorometer before being deployed on elephant seals and presents the first results obtained for the Indian sector of the Southern Ocean. This in situ system is implemented in synergy with satellite ocean colour radiometry. Satellite-derived data is limited to the surface layer and is restricted over the SO by extensive cloud cover. However, with the addition of these new tags

  20. Real time monitoring of urban surface water quality using a submersible, tryptophan-like fluorescence sensor

    NASA Astrophysics Data System (ADS)

    Khamis, Kieran; Bradley, Chris; Hannah, David; Stevens, Rob

    2014-05-01

    Due to the recent development of field-deployable optical sensor technology, continuous quantification and characterization of surface water dissolved organic matter (DOM) is possible now. Tryptophan-like (T1) fluorescence has the potential to be a particularly useful indicator of human influence on water quality as T1 peaks are associated with the input of labial organic carbon (e.g. sewage or farm waste) and its microbial breakdown. Hence, real-time recording of T1 fluorescence could be particular useful for monitoring waste water infrastructure, treatment efficiency and the identification of contamination events at higher temporal resolution than available hitherto. However, an understanding of sensor measurement repeatability/transferability and interaction with environmental parameters (e.g. turbidity) is required. Here, to address this practical knowledge gap, we present results from a rigorous test of a commercially available submersible tryptophan fluorometer (λex 285, λem 350). Sensor performance was first examined in the laboratory by incrementally increasing turbidity under controlled conditions. Further to this the sensor was integrated into a multi-parameter sonde and field tests were undertaken involving: (i) a spatial sampling campaign across a range of surface water sites in the West Midlands, UK; and (ii) collection of high resolution (sub-hourly) samples from an urban stream (Bournbrook, Birmingham, U.K). To determine the ability of the sensor to capture spatiotemporal dynamics of urban waters DOM was characterized for each site or discrete time step using Excitation Emission Matrix spectroscopy and PARAFAC. In both field and laboratory settings fluorescence intensity was attenuated at high turbidity due to suspended particles increasing absorption and light scattering. For the spatial survey, instrument readings were compared to those obtained by a laboratory grade fluorometer (Varian Cary Eclipse) and a strong, linear relationship was apparent

  1. Quantitative detection of Cryptosporidium oocyst in water source based on 18S rRNA by alternately binding probe competitive reverse transcription polymerase chain reaction (ABC-RT-PCR).

    PubMed

    Kishida, Naohiro; Miyata, Ryo; Furuta, Atsushi; Izumiyama, Shinji; Tsuneda, Satoshi; Sekiguchi, Yuji; Noda, Naohiro; Akiba, Michihiro

    2012-01-01

    We describe an assay for simple and cost-effective quantification of Cryptosporidium oocysts in water samples using a recently developed quantification method named alternately binding probe competitive PCR (ABC-PCR). The assay is based on the detection of 18S rRNA specific for Cryptosporidium oocysts. The standard curve of the ABC-PCR assay had a good fitting to a rectangular hyperbola with a correlation coefficient (R) of 0.9997. Concentrations of Cryptosporidium oocysts in real river water samples were successfully quantified by the ABC-reverse transcription (RT)-PCR assay. The quantified values by the ABC-RT-PCR assay very closely resemble those by the real-time RT-PCR assay. In addition, the quantified concentration in most water samples by the ABC-RT-PCR assay was comparable to that by conventional microscopic observation. Thus, Cryptosporidium oocysts in water samples can be accurately and specifically determined by the ABC-RT-PCR assay. As the only equipment that is needed for this end-point fluorescence assay is a simple fluorometer and a relatively inexpensive thermal cycler, this method can markedly reduce time and cost to quantify Cryptosporidium oocysts and other health-related water microorganisms.

  2. Lidar monitoring of dinoflagellate algal bloom on the Swedish coast

    NASA Astrophysics Data System (ADS)

    Barbini, Roberto; Colao, Francesco; Fantoni, Roberta; Palucci, Antonio; Ribezzo, Sergio

    1997-05-01

    The ENEA group has participated to the second ICES/IOC workshop on in situ growth rates of dinoflagellates, held at the Kristineberg Marine Research Station. The laser induced fluorescence (LIF) emission of natural communities and cultures has been monitored in vivo to obtain information on the algae species, characterized by different pigments contents, and on their photosynthetic activity, which is related to the growth rate and biomass production. A laser fluorometer and a lidar system, used for local and remote LIF excitation of phytoplankton, have been operated during the marine campaign, both exciting the sea water in the UV. In particular, the lidar fluorosensor has been equipped with a laser transmitter specifically designed to operate differentially in the pump-and-probe mode, which allows to directly measure in vivo the chlorophyll fluorescence quantum yield. Experiments were conducted on two mesocosms containing the natural community with addition of nutrients. Chemical methods have been used for calibration of the two laser apparata. Results of the campaign are presented, together with the lidar data collected from the sea surface in crossing two nearby fjords along a selected sea transect.

  3. Spring bloom onset in the Nordic Seas

    NASA Astrophysics Data System (ADS)

    Mignot, Alexandre; Ferrari, Raffaele; Mork, Kjell Arne

    2016-06-01

    The North Atlantic spring bloom is a massive annual growth event of marine phytoplankton, tiny free-floating algae that form the base of the ocean's food web and generates a large fraction of the global primary production of organic matter. The conditions that trigger the onset of the spring bloom in the Nordic Seas, at the northern edge of the North Atlantic, are studied using in situ data from six bio-optical floats released north of the Arctic Circle. It is often assumed that spring blooms start as soon as phytoplankton cells daily irradiance is sufficiently abundant that division rates exceed losses. The bio-optical float data instead suggest the tantalizing hypothesis that Nordic Seas blooms start when the photoperiod, the number of daily light hours experienced by phytoplankton, exceeds a critical value, independently of division rates. The photoperiod trigger may have developed at high latitudes where photosynthesis is impossible during polar nights and phytoplankton enters into a dormant stage in winter. While the first accumulation of biomass recorded by the bio-optical floats is consistent with the photoperiod hypothesis, it is possible that some biomass accumulation started before the critical photoperiod but at levels too low to be detected by the fluorometers. More precise observations are needed to test the photoperiod hypothesis.

  4. Fiber Optic Immunochemical Sensors For Continuous Monitoring Of Hapten Concentrations

    NASA Astrophysics Data System (ADS)

    Miller, W. Greg; Anderson, F. Philip

    1989-06-01

    We describe a fiber optic sensor based on a homogeneous fluorescence energy transfer immunoassay which operates in a continuous, reversible manner to quantitate the anticonvulsant drug phenytoin. B-phycoerythrin-phenytoin and Texas Red labeled anti-phenytoin antibody were sealed inside a short length of cellulose dialysis tubing which was cemented to the distal end of an optical fiber. When the sensor was placed into a solution of phenytoin, the drug crossed the dialysis membrane, displaced a fraction of the B-phycoerythrin-phenytoin from the antibody, and produced a change in fluorescence signal which was measured with a fiber optic fluorometer. The sensor had a concentration response of 5 to 500μmo1/L phenytoin with a response time of 5 to 15 min and precision of <2.5% CV. The chemical kinetics of the antibody-hapten indicator reaction were modeled mathematically and simulation showed that response time in the minutes range can be achieved when the dissociation rate constant is greater than approximately 10-3 sec-1. The dissociation rate constant influences the time to reach equilibrium and the unbound P* concentration range available for instrumental measurement. The ratio of the labeled and unlabeled hapten dissociation rate constants influences the analyte concentration range to which the sensor will respond.

  5. Cross-shore surfzone tracer dispersion in an alongshore current

    NASA Astrophysics Data System (ADS)

    Clark, David B.; Feddersen, Falk; Guza, R. T.

    2010-10-01

    Cross-shore surfzone tracer dispersion in a wave driven alongshore current is examined over a range of wave and current conditions with 6 continuous dye releases, each roughly 1-2 hours in duration, at Huntington Beach, California. Fluorescent dye tracer released near the shoreline formed shore parallel plumes that were sampled on repeated cross-shore transects with a jet ski mounted fluorometer. Ensemble averaged cross-shore tracer concentration profiles are generally shoreline attached (maximum at or near the shoreline), with increasing cross-shore widths and decreasing peak values with downstream distance. More than a few 100 m from the source, tracer is often well mixed across the surfzone (i.e., saturated) with decreasing tracer concentrations farther seaward. For each release, cross-shore surfzone absolute diffusivities are estimated using a simple Fickian diffusion solution with a no-flux boundary at the shoreline, and range from 0.5-2.5 m2 s-1. Surfzone diffusivity scalings based on cross-shore bore dispersion, surfzone eddy mixing length, and undertow driven shear dispersion are examined. The mixing-length scaling has correlation r2 = 0.59 and the expected best-fit slope <1, indicating that horizontal rotational motions are important for cross-shore tracer dispersion in the surfzone.

  6. Spectral fluorometric characterization of phytoplankton community composition using the Algae Online Analyser.

    PubMed

    Richardson, Tammi L; Lawrenz, Evelyn; Pinckney, James L; Guajardo, Rodney C; Walker, Elyse A; Paerl, Hans W; MacIntyre, Hugh L

    2010-04-01

    The utility of a multiple-fixed-wavelength spectral fluorometer, the Algae Online Analyser (AOA), as a means of quantifying phytoplankton biomass and community composition was tested using natural communities from two southeastern United States estuaries, North Inlet, South Carolina, and the Neuse River Estuary, North Carolina. Estimates of biomass (as chlorophyll a) were correlated with HPLC values and variations (usually over-estimates) were consistent with effects of light intensity and nutrient availability on fluorescence quenching. AOA estimates of taxonomic structure were consistent with those from HPLC-derived marker pigments by ChemTax, with both methods indicating domination by chromophytes and green algae in North Inlet and chromophytes and cyanobacteria in the Neuse. We recommend frequent calibration by discrete sample collection, and calibration with species representative of the region of interest. Overall, the AOA appears to be a useful tool for monitoring of phytoplankton community composition, especially as an early warning system for the detection of harmful algal blooms. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  7. Autofluorescence lifetime metrology for label-free detection of cartilage matrix degradation

    NASA Astrophysics Data System (ADS)

    Nickdel, Mohammad B.; Lagarto, João. L.; Kelly, Douglas J.; Manning, Hugh B.; Yamamoto, Kazuhiro; Talbot, Clifford B.; Dunsby, Christopher; French, Paul; Itoh, Yoshifumi

    2014-03-01

    Degradation of articular cartilage extracellular matrix (ECM) by proteolytic enzyme is the hallmark of arthritis that leads to joint destruction. Detection of early biochemical changes in cartilage before irreversible structural damages become apparent is highly desirable. Here we report that the autofluorescence decay profile of cartilage is significantly affected by proteolytic degradation of cartilage ECM and can be characterised by measurements of the autofluorescence lifetime (AFL). A multidimensional fluorometer utilizing ultraviolet excitation at 355 nm or 375 nm coupled to a fibreoptic probe was developed for single point time-resolved AFL measurements of porcine articular cartilage explants treated with different proteinases. Degradation of cartilage matrix components by treating with bacterial collagenase, matrix metalloproteinase 1, or trypsin resulted in significant reduction of AFL of the cartilage in both a dose and time dependent manner. Differences in cartilage AFL were also confirmed by fluorescence lifetime imaging microscopy (FLIM). Our data suggest that AFL of cartilage tissue is a potential non-invasive readout to monitor cartilage matrix integrity that may be utilized for diagnosis of arthritis as well as monitoring the efficacy of anti-arthritic therapeutic agents.

  8. Marine Arctic Ecosystem Study (MARES) - An Integrated Approach to the Dynamics of the Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Wiese, F. K.; Gryba, R.; Kelly, B. P.

    2016-02-01

    MARES is an integrated ecosystem research initiative coordinated and planned by the Bureau of Ocean Energy Management, the Office of Naval Research, the National Aeronautics and Space Administration, the U.S. Coast Guard, and Shell through the National Oceanographic Partnership Program. The overarching goal is to advance our knowledge of the structure and function of the Beaufort Sea marine ecosystem so as to link atmospheric and oceanic drivers to sea ice patterns and marine mammal distribution and availability to local subsistence communities. The study, funded in 2014, focuses on the marine ecosystem along the Beaufort Sea shelf from Barrow, Alaska to the Mackenzie River delta in Canada and is scheduled to include bio-physical moorings along the US-Canadian border, glider deployments packed with bio-physical sensors, tagging of whales and ice-associated seals with satellite CTD-Fluorometer tags, biophysical and chemical cruises including the measurement and characterization of hydrography, ice, nutrients, primary and secondary production, carbon budgets, benthic fauna, fish, as well as analysis of freshwater input and chemical loadings, and ecosystem modeling. This presentation will focus on preliminary results from the ice seal tagging that started in the summer of 2015 and describe some of the planning and possibilities for partnerships for the more comprehensive 2016 field season and beyond.

  9. Arsenic toxicity in the water weed Wolffia arrhiza measured using Pulse Amplitude Modulation Fluorometry (PAM) measurements of photosynthesis.

    PubMed

    Ritchie, Raymond J; Mekjinda, Nutsara

    2016-10-01

    Accumulation of arsenic in plants is a serious South-east Asian environmental problem. Photosynthesis in the small aquatic angiosperm Wolffia arrhiza is very sensitive to arsenic toxicity, particularly in water below pH 7 where arsenite (As (OH)3) (AsIII) is the dominant form; at pH >7 AsO4(2-) (As(V) predominates). A blue-diode PAM (Pulse Amplitude Fluorometer) machine was used to monitor photosynthesis in Wolffia. Maximum gross photosynthesis (Pgmax) and not maximum yield (Ymax) is the most reliable indicator of arsenic toxicity. The toxicity of arsenite As(III) and arsenate (H2AsO4(2-)) As(V) vary with pH. As(V) was less toxic than As(III) at both pH 5 and pH 8 but both forms of arsenic were toxic (>90% inhibition) at below 0.1molm(-3) when incubated in arsenic for 24h. Arsenite toxicity was apparent after 1h based on Pgmax and gradually increased over 7h but there was no apparent effect on Ymax or photosynthetic efficiency (α0).

  10. Molecular diagnostics in a teacup: Non-Instrumented Nucleic Acid Amplification (NINA) for rapid, low cost detection of Salmonella enterica.

    PubMed

    Kubota, Ryo; Labarre, Paul; Weigl, Bernhard H; Li, Yong; Haydock, Paul; Jenkins, Daniel M

    2013-04-01

    We report on the use of a novel non-instrumented platform to enable a Loop Mediated isothermal Amplification (LAMP) based assay for Salmonella enterica. Heat energy is provided by addition of a small amount (<150 g) of boiling water, and the reaction temperature is regulated by storing latent energy at the melting temperature of a lipid-based engineered phase change material. Endpoint classification of the reaction is achieved without opening the reaction tube by observing the fluorescence of sequence-specific FRET-based assimilating probes with a simple handheld fluorometer. At or above 22°C ambient temperature the non-instrumented devices could maintain reactions above a threshold temperature of 61°C for over 90 min-significantly longer than the 60 min reaction time. Using the simple format, detection limits were less than 20 genome copies for reactions run at ambient temperatures ranging from 8 to 36°C. When used with a pre-enrichment step and non-instrumented DNA extraction device, trace contaminations of Salmonella in milk close to 1 CFU/mL could be reliably detected. These findings illustrate that the non- instrumented amplification approach is a simple, viable, low-cost alternative for field-based food and agricultural diagnostics or clinical applications in developing countries.

  11. Halophila stipulacea: survival under adverse conditions.

    NASA Astrophysics Data System (ADS)

    Morton, C. R., Jr.; Primack, A. G.; Wyllie-Echeverria, S.

    2016-02-01

    Halophila stipulacea is an invasive seagrass species originally native to the Indian Ocean. It invaded the Mediterranean Sea shortly after the opening of the Suez Canal, and has recently been found in the Caribbean. It has been suggested that it arrived in the Mediterranean attached to small pleasure craft, fishing craft, or small cargo vessels. This research examines the feasibility of these methods of transport and the possibility that arrived transported by ocean currents. To investigate potential transport vectors, we collected rooted samples of H. stipulacae from Brewers Bay on the island of Saint Thomas, USVI, and exposed them to conditions that would be experienced under each alternative method of transport. The health of the samples was monitored using a FLOURPEN FP 100 portable fluorometer. Rhizomes, and associated leaf pairs declined rapidly when exposed to air, submersed in freshwater, or kept damp in a towel soaked in seawater, but survived for more than 5 weeks when left floating in a bucket submersed in a seawater tank. Water temperature ranged between 27C and 30C during the experiment. This suggests that it might be possible for H. stipulacae to cross the Atlantic aided by currents.

  12. Real-time frequency-domain fiber optic sensor for intra-arterial blood oxygen measurements

    NASA Astrophysics Data System (ADS)

    Alcala, J. R.; Scott, Ian L.; Parker, Jennifer W.; Atwater, Beauford W.; Yu, Clement; Fischer, Russell; Bellingrath, K.

    1993-05-01

    A real time frequency domain phosphorimeter capable of measuring precise and accurate excited state lifetimes for determining oxygen is described. This frequency domain instrument does not make use of cross correlation techniques traditionally used in frequency domain fluorometers. Instead, the electrical signal from the detector is filtered to contain only the first several harmonics. This filtered signal is then sampled and averaged over a few thousand cycles. The absolute phase and absolute modulation of each sampled harmonic of the excitation and of the luminescence is computed by employing fast Fourier transform algorithms. The phase delay and the modulation ratio is then calculated at each harmonic frequency. A least squares fit is performed in the frequency domain to obtain the lifetimes of discrete exponentials. Oxygen concentrations are computed from these lifetimes. Prototypes based on these techniques were built employing commercially available components. Results from measurements in saline solution and in the arterial blood of dogs show that oxygen concentrations can be determined reproducibly. The system drift is less than 1% in over 100 hours of continuous operation. The performance of fiber optic sensors was evaluated in dogs over a period of 10 hours. The sensors tracked changes in arterial oxygen tension over the course of the experiment without instabilities. The overall response of the system was about 90 seconds. The update time was 3 seconds.

  13. Real-time imaging of hydrogen peroxide dynamics in vegetative and pathogenic hyphae of Fusarium graminearum

    PubMed Central

    Mentges, Michael; Bormann, Jörg

    2015-01-01

    Balanced dynamics of reactive oxygen species in the phytopathogenic fungus Fusarium graminearum play key roles for development and infection. To monitor those dynamics, ratiometric analysis using the novel hydrogen peroxide (H2O2) sensitive fluorescent indicator protein HyPer-2 was established for the first time in phytopathogenic fungi. H2O2 changes the excitation spectrum of HyPer-2 with an excitation maximum at 405 nm for the reduced and 488 nm for the oxidized state, facilitating ratiometric readouts with maximum emission at 516 nm. HyPer-2 analyses were performed using a microtiter fluorometer and confocal laser scanning microscopy (CLSM). Addition of external H2O2 to mycelia caused a steep and transient increase in fluorescence excited at 488 nm. This can be reversed by the addition of the reducing agent dithiothreitol. HyPer-2 in F. graminearum is highly sensitive and specific to H2O2 even in tiny amounts. Hyperosmotic treatment elicited a transient internal H2O2 burst. Hence, HyPer-2 is suitable to monitor the intracellular redox balance. Using CLSM, developmental processes like nuclear division, tip growth, septation, and infection structure development were analyzed. The latter two processes imply marked accumulations of intracellular H2O2. Taken together, HyPer-2 is a valuable and reliable tool for the analysis of environmental conditions, cellular development, and pathogenicity. PMID:26446493

  14. Examining concentrations and molecular weights of thiols in microorganism cultures and in Churchill River (Manitoba) using a fluorescent-labeling method coupled to asymmetrical flow field-flow fractionation.

    PubMed

    Mangal, Vaughn; Guéguen, Celine

    2015-06-01

    In this study, molecular weights of thiols from four laboratory cultures (Scenedesmus obliquus, Chlorella vulgaris, Euglena gracilis, and Attheya septentrionalis) and the Churchill River (Manitoba) were assessed using a fluorescent-labeling method such as monobromotrimethylammoniobimane (qBBr) and asymmetrical flow field-flow fractionation (AF4) coupled to a fluorescence detector. Concentrations of thiols in extracellular fractions ranged from 6.39 ± 3.39 to 39.2 ± 7.43 μmol g(-1), and intracellular concentrations ranged from 11.5 ± 4.52 to 41.0 ± 4.1 μmol g(-1). In addition, molecular weights (MW) of intracellular thiol ranged from 493 ± 24 to 946 ± 12 Da whereas extracellular thiol MWs varied from 443 ± 36 to 810 ± 174 Da. The novel method of combining AF4 to an on-line fluorometer and the incorporation of the thiol tag provided information regarding thiol concentration and composition of controlled and natural systems. Furthermore, the proposed methods allow for the simultaneous measurement of thiol and DOM MWs produced by microorganisms. By assessing characteristics of naturally produced thiols and lab-grown thiols, information regarding heavy metal complexation can be determined.

  15. SmartFluo: A Method and Affordable Adapter to Measure Chlorophyll a Fluorescence with Smartphones

    PubMed Central

    Friedrichs, Anna; Busch, Julia Anke; van der Woerd, Hendrik Jan; Zielinski, Oliver

    2017-01-01

    In order to increase the monitoring capabilities of inland and coastal waters, there is a need for new, affordable, sensitive and mobile instruments that could be operated semi-automatically in the field. This paper presents a prototype device to measure chlorophyll a fluorescence: the SmartFluo. The device is a combination of a smartphone offering an intuitive operation interface and an adapter implying a cuvette holder, as well as a suitable illumination source. SmartFluo is based on stimulated fluorescence of water constituents such as chlorophyll a. The red band of the digital smartphone camera is sensitive enough to detect quantitatively the characteristic red fluorescence emission. The adapter contains a light source, a strong light emitting diode and additional filters to enhance the signal-to-noise ratio and to suppress the impact of scattering. A novel algorithm utilizing the red band of the camera is provided. Laboratory experiments of the SmartFluo show a linear correlation (R2 = 0.98) to the chlorophyll a concentrations measured by reference instruments, such as a high-performance benchtop laboratory fluorometer (LS 55, PerkinElmer). PMID:28346338

  16. In vivo dynamics of enterovirus protease revealed by fluorescence resonance emission transfer (FRET) based on a novel FRET pair

    SciTech Connect

    Hsu, Y.-Y.; Liu, Y.-N.; Wang Wenyen; Kao, Fu-Jen; Kung, S.-H. . E-mail: szkung@ym.edu.tw

    2007-02-23

    An in vivo protease assay suitable for analysis by fluorescence resonance energy transfer (FRET) was developed on the basis of a novel FRET pair. The specifically designed fusion substrate consists of green fluorescent protein 2 (GFP{sup 2})-peptide-red fluorescent protein 2 (DsRed2), with a cleavage motif for the enterovirus 2A protease (2A{sup pro}) embedded within the peptide region. FRET can be readily visualized in real-time from cells expressing the fusion substrate until a proteolytic cleavage by 2A{sup pro} from the input virus. The level of FRET decay is a function of the amount and infection duration of the inoculated virus as measured by a fluorometer assay. The FRET biosensor also responded well to other related enteroviruses but not to a phylogenetically distant virus. Western blot analysis confirmed the physical cleavage of the fusion substrate upon the infections. The study provides proof of principle for applying the FRET technology to diagnostics, screening procedures, and cell biological research.

  17. Adaptation and optimization of a fluorescence-based assay for in vivo antimalarial drug screening.

    PubMed

    Arias, Maria H; Deharo, Eric; Valentin, Alexis; Garavito, Giovanny

    2017-07-01

    The in vivo efficacy of potential antimalarials is usually evaluated by direct microscopic determination of the parasitaemia of Plasmodium-infected mice on Giemsa-stained blood smears. This process is time-consuming, requires experienced technicians and is not automatable. Therefore, we optimized a SYBR Green I (SYBRG I) fluorescence-based assay to fluorometers commonly available in many research laboratories. This technique was originally developed to assess parasitaemia in humans by cytometry. We defined optimal conditions with Plasmodium berghei-infected mice, standard lysis buffer (Tris, EDTA, saponin and Triton), whole blood cells and 2 h staining incubation with SYBRG I 2X. The fluorescence background generated by uninfected whole blood cells was low (around 4.6%), and the linearity high (r (2) = 0.96), with parasitaemia ranging from 1.4 to 60%. The Bland-Altman plot showed a strong correlation between SYBRG I and Giemsa gold standard method; Z'-factor was >0.5. These findings suggest that our fluorescence-based assay is suitable for in vivo antimalarial drug assessment in a malaria murine model. It can help to overcome the human bias found with microscopic techniques.

  18. Detection of salmonellas by DNA hybridization with a fluorescent alkaline phosphatase substrate.

    PubMed

    Cano, R J; Torres, M J; Klem, R E; Palomares, J C; Casadesus, J

    1992-05-01

    This study evaluates a DNA hybridization assay for salmonella with AttoPhos (JBL Scientific, San Luis Obispo, CA), a fluorescent substrate for alkaline phosphatase. The probe used (50 ng/ml) was a biotinylated 600 bp fragment consisting of a tandem repeat of an insertion sequence (IS200) found in most Salmonella spp. evaluated. The hybridization was carried out at 65 degrees C for 2 h without prior prehybridization and hybrids were detected by the addition of a streptavidin-alkaline phosphatase conjugate. Circles (5 mm) were cut from the membrane and placed in a cuvette containing 1 ml of 1 mmol/l AttoPhos. The reaction was evaluated after 30 min at 37 degrees C with a fluorometer with an excitation wavelength of 440 nm and an emission wavelength of 550 nm. The sensitivity of the probe was estimated to be 10,000 copies of target DNA or 5 x 10(-20) mol of DNA. All 74 salmonella strains tested reacted with the probe but none of the 98 heterologous species tested gave positive results. The results of this study indicate that our assay method, which employs a biotinylated tandem repeat of IS200 and AttoPhos, is a specific and highly sensitive quantitative method for the detection of salmonellas.

  19. Development of a no-wash assay for mitochondrial membrane potential using the styryl dye DASPEI.

    PubMed

    Jensen, Kristian H R; Rekling, Jens C

    2010-10-01

    Mitochondrial dysfunction is a hallmark of several diseases and may also result from drugs with unwanted side effects on mitochondrial biochemistry. The mitochondrial membrane potential is a good indicator of mitochondrial function. Here, the authors have developed a no-wash mitochondrial membrane potential assay using 2-(4-(dimethylamino)styryl)-N-ethylpyridinium iodide (DASPEI), a rarely used mitochondrial potentiometric probe, in a 96-well format using a fluorescent plate reader. The assay was validated using 2 protonophores (CCCP, DNP), which are known uncouplers, and the neuroleptic thioridazine, which is a suspected mitochondrial toxicant. CCCP and DNP have short-term depolarizing effects, and thioridazine has long-term hyperpolarizing effects on the mitochondrial membrane potential of Chinese hamster ovary (CHO) cells. The assay also detected changes of the mitochondrial membrane potential in CHO cells exposed to cobalt (mimicking hypoxia) and in PC12 cells exposed to amyloid β, demonstrating that the assay can be used in cellular models of hypoxia and Alzheimer's disease. The assay needs no washing steps, has a Z' value >0.5, can be used on standard fluorometers, has good post liquid-handling stability, and thus is suitable for large-scale screening efforts. In summary, the DASPEI assay is simple and rapid and may be of use in toxicological testing, drug target discovery, and mechanistic models of diseases involving mitochondrial dysfunction.

  20. Pulsed laser fluorometry for environmental monitoring

    SciTech Connect

    Saunders, G. C.; Martin, J. C.; Jett, J. H.; Wilder, M. E.; Martinez, A.; Bentley, B. F.; Lopez, J.; Hutson, L.

    1990-01-01

    A compact pulsed laser fluorometer has been incorporated into a continuous flow system developed to detect acetylcholinesterase (AChE) inhibitors and/or primary amine compounds in air and water. A pulsed nitrogen laser pumped dye laser excites fluorescent reactants which flow continuously through a quartz flow cell. Data are collected, analyzed, and displayed using a Macintosh II personal computer. For detection of cholinesterase inhibitors the fluorogenic substrate N methylindoxyl acetate is used to monitor the activity of immobilized enzyme. Presence of inhibitors results in a decrease of steady state fluorescence. Detection of compounds containing primary amines is based on their reaction with fluorescamine to rapidly produce intensely fluorescent products. Compounds of interest to our research were amino acids, peptides, and proteins. An increase in steady state fluorescence could be cause to evaluate the reasons for the change. The detection limit of the protein, bovine serum albumin (BSA) in water is 10 ppT. Nebulized BSA concentrated by the LANL air sampler can be detected at sub ppT original air concentration. 16 refs., 14 figs., 3 tabs.

  1. Instrumentation for plant health and growth

    NASA Astrophysics Data System (ADS)

    Schlager, K. J.

    1994-11-01

    Comprehensive spectroscopic monitoring of plant health and growth in bioregenerative life support system environments is possible using a variety of spectrometric technologies. Absorption spectrometry and atomic emission spectrometry in combination allow for direct, on-line, reagentless monitoring of plant nutrients from nitrate and potassium to micronutrients such as copper and zinc. Fluorometric spectrometry is ideal for the on-line detection, identification and quantification of bacteria and fungi. Liquid Atomic Emission Spectrometry (LAES) is a new form of spectrometry that allows for direct measurement of atomic emission spectra in liquids. An electric arc is generated by a pair of electrodes in the liquid to provide the energy necessary to break molecular bonds and reduce the substance to atomic form. With a fiber probe attached to the electrodes, spectral light can be transmitted to a photodiode array spectrometer for light dispersion and analysis. Ultraviolet (UV) absorption spectrometry is a long-established technology, but applications typically have required specific reagents to produce an analyte-specific absorption. Nitrate and iron nutrients have native UV absorption spectra that have been used to accurately determine nutrient concentrations at the +/- 5% level. Fluorescence detection and characterization of microbes is based upon the native fluorescent signatures of most microbiological species. Spectral and time-resolved fluorometers operating with remote fiber-optic probes will be used for on-line microbial monitoring in plant nutrient streams.

  2. Optical studies of tissue mitochondrial redox in isolated perfused rat lungs

    NASA Astrophysics Data System (ADS)

    Sepehr, R.; Staniszewski, K.; Jacobs, E. R.; Audi, S.; Ranji, M.

    2012-02-01

    Through the monitoring of the auto-fluorescent mitochondrial metabolic coenzymes, NADH (Nicotinamide Adenine Dinucleotide) and FAD (Flavoprotein Adenine Dinucleotide), the redox state of metabolism can be probed in real time in many intact organs, but its use has not been fully developed in lungs. The ratio of these fluorophores, (NADH/FAD), referred to as the mitochondrial redox ratio (RR), can be used as a quantitative metabolic marker of tissue. We have designed a fluorometer that can be used to monitor lung surface NADH and FAD fluorescence in isolated perfused lungs. Surface fluorescence NADH and FAD signals were acquired in the absence (control) and presence of pentachlorophenol (PCP), rotenone, and potassium cyanide (KCN). Rotenone, an inhibitor of complex I, increased RR by 18%, predominantly due to an increase in NADH signal. KCN, an inhibitor of complex IV reduced the chain and resulted in an increase of 33% in RR, as a result of 23% increase in NADH and 8% in FAD . PCP, an uncoupler which oxidizes the respiratory chain, decreased RR by 18% as a result of 14% decrease in NADH signal and 4% increase in FAD signal. These results demonstrate the ability of surface fluorometry to detect changes in lung tissue mitochondrial redox state in isolated perfused lungs.

  3. Proliferative effect of whey from cows' milk obtained at two different stages of pregnancy measured in MCF-7 cells.

    PubMed

    Nielsen, Tina S; Andersen, Charlotte; Sejrsen, Kris; Purup, Stig

    2012-02-01

    Dietary estrogens may play a role in the etiology of hormone-dependent cancers like breast cancer. Cow's milk contains various endogenous estrogens and feed derived phytoestrogens that potentially contribute to an estrogenic effect of milk in consumers, and therefore we evaluated the effect of milk (whey) in a proliferation assay with estrogen-sensitive MCF-7 human breast cancer cells. Milk samples were obtained from 22 cows representing different stages of pregnancy (first and second half) and whey was produced from the milk. 0·1, 0·25 or 0·5% whey was included in the cell culture medium and after 6 days of treatment cell proliferation was assessed by a colorimetric method with a fluorometer. Whey induced significant (P<0·05) proliferative effects compared with control cells with no added whey at all concentrations tested. There was no difference in the proliferative effect of whey depending on the stage of pregnancy from which the milk was obtained. We did not observe anti-proliferative effects when whey was tested in the presence of 10 pm estradiol in the medium. In conclusion, these results indicate that whey, irrespective of the pregnancy stage from which the milk was obtained induced a significant proliferative response in MCF-7 cells and no anti-proliferative effect, which may be caused, at least in part, by estrogens present in milk. The implications of our findings in relation to for example breast cancer will have to be studied further in other model systems preferentially in vivo.

  4. Modified spectrophotometer for multi-dimensional circular dichroism/fluorescence data acquisition in titration experiments: application to the pH and guanidine-HCI induced unfolding of apomyoglobin.

    PubMed Central

    Ramsay, G; Ionescu, R; Eftink, M R

    1995-01-01

    In a previous paper (Ramsay and Eftink, Biophys. J. 66:516-523) we reported the development of a modified spectrophotometer that can make nearly simultaneous circular dichroism (CD) and fluorescence measurements. This arrangement allows multiple data sets to be collected during a single experiment, resulting in a saving of time and material, and improved correlation between the different types of measurements. The usefulness of the instrument was shown by thermal melting experiments on several different protein systems. This CD/fluorometer spectrophotometer has been further modified by interfacing with a syringe pump and a pH meter. This arrangement allows ligand, pH, and chemical denaturation titration experiments to be performed while monitoring changes in the sample's CD, absorbance, fluorescence, and light scattering properties. Our data acquisition program also has an ability to check whether the signals have approached equilibrium before the data is recorded. For performing pH titrations we have developed a procedure which uses the signal from a pH meter in a feedback circuit in order to collect data at evenly spaced pH intervals. We demonstrate the use of this instrument with studies of the unfolding of sperm whale apomyoglobin, as induced by acid pH and by the addition of guanidine-HCI. Images FIGURE 2 PMID:8527683

  5. Micro-segmented flow and multisensor-technology for microbial activity profiling.

    PubMed

    Kürsten, Dana; Kothe, Erika; Wetzel, Katharina; Bergmann, Katja; Köhler, J Michael

    2014-01-01

    The combination of micro-segmented flow with miniaturized flow-through multisensor-technology has been utilized for metabolite profiling of soil bacteria. Series of sub-μl segments were generated containing soil sample slurry from historic copper mining sites and exposed to heavy metal salts of copper and nickel. Segments were examined for bacterial growth and spectral properties as well as for the effect of heavy metal-treatment after different incubation times. In order to evaluate microbial growth, extinction was recorded with 4 different spectral channels. Fluorescence was measured using a microflow-through fluorometer to detect both growth and production of fluorescent dyes or metabolites. The incidence of single segments with enhanced absorption in one of the spectral channels or enhanced fluorescence was scored to detect soil microorganisms with interesting properties for further screening. The study could show that the number of vegetated segments, the density of microorganisms in the segments after cultivation and the spectral response are different for separate soil samples and different metals. Thus, the highly parallelized and miniaturized segmented flow method is a promising tool for profiling of soil samples with regard to identifying micro-organisms with interesting profiles for secondary metabolite-production.

  6. Fluorogenic Cell-Based Biosensors for Monitoring Microbes

    NASA Technical Reports Server (NTRS)

    Curtis, Theresa; Salazar, Noe; Tabb, Joel; Chase, Chris

    2010-01-01

    Fluorogenic cell-based sensor systems for detecting microbes (especially pathogenic ones) and some toxins and allergens are undergoing development. These systems harness the natural signaltransduction and amplification cascades that occur in mast cells upon activation with antigens. These systems include (1) fluidic biochips for automated containment of samples, reagents, and wastes and (2) sensitive, compact fluorometers for monitoring the fluorescent responses of mast cells engineered to contain fluorescent dyes. It should be possible to observe responses within minutes of adding immune complexes. The systems have been shown to work when utilizing either immunoglobulin E (IgE) antibodies or traditionally generated rat antibodies - a promising result in that it indicates that the systems could be developed to detect many target microbes. Chimeric IgE antibodies and rat immunoglobulin G (IgG) antibodies could be genetically engineered for recognizing biological and chemical warfare agents and airborne and food-borne allergens. Genetic engineering efforts thus far have yielded (1) CD14 chimeric antibodies that recognize both Grampositive and Gram-negative bacteria and bind to the surfaces of mast cells, eliciting a degranulation response and (2) rat IgG2a antibodies that act similarly in response to low levels of canine parvovirus.

  7. A resettable in-line particle concentrator using AC electrokinetics for distributed monitoring of microalgae in source waters

    SciTech Connect

    Yuan, Quan; Wu, Jayne; Greenbaum, Elias; Evans, Barbara R.

    2016-12-29

    Green algae have been studied as an important and effective biomarker to indicate water quality due to their sensitivity to toxic agents in freshwater sources. But, conventional methods to monitor algal physiology use a chlorophyll fluorometer whose use is hampered by high-cost, large footprint, and limited sensitivity for practical samples containing low algal concentration. In order to overcome these constraints, we developed a multi-level electrode platform for resettable trapping of algae via AC electro-osmosis (ACEO) and negative dielectrophoresis. Preliminary experiments were performed in freshwater with conductivity of 0.02 S/m. Algal trapping was demonstrated at a low voltage of 2 V. The concentration effect was experimentally verified by measuring the fluorescence intensity of algae and using hemocytometer counting chambers at the inlet and outlet of the multilevel microchannel lab-on-a-chip. An optimal frequency was found for trapping, which agrees with the frequency dependence of ACEO flow velocity. Through-flow rate and electrode dimensions were optimized as well. Trapping efficiencies within the range of 26% - 65% have been obtained. A maximum trapping rate of 182 cells/s was obtained with a flow rate of 20 l/min. Our lab-on-a-chip shows high potential for improving the limit of detection in algal monitoring and enabling the development of a portable, integrated and automated system for monitoring the quality of source drinking waters.

  8. A resettable in-line particle concentrator using AC electrokinetics for distributed monitoring of microalgae in source waters

    DOE PAGES

    Yuan, Quan; Purdue Univ., West Lafayette, IN; Wu, Jayne; ...

    2016-12-29

    Green algae have been studied as an important and effective biomarker to indicate water quality due to their sensitivity to toxic agents in freshwater sources. But, conventional methods to monitor algal physiology use a chlorophyll fluorometer whose use is hampered by high-cost, large footprint, and limited sensitivity for practical samples containing low algal concentration. In order to overcome these constraints, we developed a multi-level electrode platform for resettable trapping of algae via AC electro-osmosis (ACEO) and negative dielectrophoresis. Preliminary experiments were performed in freshwater with conductivity of 0.02 S/m. Algal trapping was demonstrated at a low voltage of 2 V.more » The concentration effect was experimentally verified by measuring the fluorescence intensity of algae and using hemocytometer counting chambers at the inlet and outlet of the multilevel microchannel lab-on-a-chip. An optimal frequency was found for trapping, which agrees with the frequency dependence of ACEO flow velocity. Through-flow rate and electrode dimensions were optimized as well. Trapping efficiencies within the range of 26% - 65% have been obtained. A maximum trapping rate of 182 cells/s was obtained with a flow rate of 20 l/min. Our lab-on-a-chip shows high potential for improving the limit of detection in algal monitoring and enabling the development of a portable, integrated and automated system for monitoring the quality of source drinking waters.« less

  9. Trace Ammonia Sensors Based on Fluorescent Near-Infrared-Emitting aza-BODIPY Dyes.

    PubMed

    Strobl, Martin; Walcher, Anna; Mayr, Torsten; Klimant, Ingo; Borisov, Sergey M

    2017-03-07

    Highly sensitive ammonia sensors for environmental monitoring are presented. The sensing materials are based on fluorescent BF2-chelated tetraarylazadipyrromethene dyes (aza-BODIPYs) dyes physically entrapped in polyurethane hydrogels and dispersed in silicone rubber. This layer is covered by a hydrophobic porous Teflon membrane used as an additional proton barrier and light scattering layer. The dual-lifetime referenced (DLR) sensors make use of near-infrared (NIR)-emitting Egyptian blue as a reference material and in combination with optical fibers are read-out via a compact phase-fluorometer. The detectable concentration range can be tuned by the choice of aza-BODIPY dye or/and the hydrogel matrix. The most sensitive sensor has a limit of detection (LOD) of 0.11 μg/L and the upper detectable concentration of 300 μg/L. No cross-sensitivity toward pH is observed. The sensors show remarkable operational stability with no noticeable drift over a period of 2 weeks.

  10. Unequal allocation of excitation energy between photosystem II and I reduces cyanolichen photosynthesis in blue light.

    PubMed

    Solhaug, Knut Asbjørn; Xie, Li; Gauslaa, Yngvar

    2014-08-01

    Photosynthesis was compared in two cyanobacterial lichens (Lobaria hallii and Peltigera praetextata) and two green algal lichens (Lobaria pulmonaria and Peltigera leucophlebia) exposed to red, green or blue light. Cyanolichens had substantially lower photosynthetic CO(2) uptake and O(2) evolution than the green algal lichens in blue light, but slightly higher photosynthesis in red and green light. The effective quantum yield of photosystem (PS) II (Φ(PSII)) decreased with increasing red and green light for all species, but in blue light this response occurred in green algal lichens only. Cyanolichen Φ(PSII) increased with increasing blue light at low irradiances, but decreased at stronger exposures. However, after adding red light the efficiency of blue light for photosynthetic O(2) evolution increased by 2.4 times. Because phycobilisomes associated with PSII have a low blue light absorption, our results are consistent with blue light absorption mainly by Chl in PSI. Thereby, unequal allocation of excitation energy between PSII and PSI results in low cyanolichen photosynthesis under blue light. This is new knowledge in the science of lichenology with important implications for e.g. the reliability of using Chl fluorometers with blue light for cyanolichens.

  11. Oil Droplet Size Distribution and Optical Properties During Wave Tank Simulated Oil Spills

    NASA Astrophysics Data System (ADS)

    Conmy, R. N.; Venosa, A.; Courtenay, S.; King, T.; Robinson, B.; Ryan, S.

    2013-12-01

    Fate and transport of spilled petroleum oils in aquatic environments is highly dependent upon oil droplet behavior which is a function of chemical composition, dispersibility (natural and chemically-enhanced) and droplet size distribution (DSD) of the oil. DSD is influenced by mixing energy, temperature, salinity, pressure, presence of dissolved and particulate materials, flow rate of release, and application of dispersants. To better understand DSD and droplet behavior under varying physical conditions, flask-scale experiments are often insufficient. Rather, wave tank simulations allow for scaling to field conditions. Presented here are experiment results from the Bedford Institute of Oceanography wave tank facility, where chemically-dispersed (Corexit 9500; DOR = 1:20) Louisiana Sweet crude, IFO-120 and ANS crude oil were exposed to mixing energies to achieve dispersant effectiveness observed in the field. Oil plumes were simulated, both surface and subsea releases with varying water temperature and flow rate. Fluorometers (Chelsea Technologies Group AQUATracka, Turner Designs Cyclops, WET Labs Inc ECO) and particle size analyzers (Sequoia LISST) were used to track the dispersed plumes in the tank and characterize oil droplets. Sensors were validated with known oil volumes (down to 300 ppb) and measured Total Petroleum Hydrocarbons (TPH) and Benzene-Toluene-Ethylbenzene-Xylene (BTEX) values. This work has large implications for tracking surface and deep sea oil plumes with fluorescence and particle size analyzers, improved weathering and biodegradation estimates, and understanding the fate and transport of spill oil.

  12. Eat-by-light fiber-optic and micro-optic devices for food quality and safety assessment

    NASA Astrophysics Data System (ADS)

    Mignani, A. G.; Ciaccheri, L.; Cucci, C.; Mencaglia, A. A.; Cimato, A.; Attilio, C.; Thienpont, H.; Ottevaere, H.; Paolesse, R.; Mastroianni, M.; Monti, D.; Buonocore, G.; Del Nobile, A.; Mentana, A.; Grimaldi, M. F.; Dall'Asta, C.; Faccini, A.; Galaverna, G.; Dossena, A.

    2007-06-01

    A selection is presented of fiber-optic and micro-optic devices that have been designed and tested for guaranteeing the quality and safety of typical foods, such as extra virgin olive oil, beer, and milk. Scattered colorimetry is used to authenticate various types of extra virgin olive oil and beer, while a fiber-optic-based device for UV-VIS-NIR absorption spectroscopy is exploited in order to obtain the hyperspectral optical signature of olive oil. This is done not only for authentication purposes, but also so as to correlate the spectral data with the content of fatty acids, which are important nutritional factors. A micro-optic sensor for the detection of olive oil aroma that is capable of distinguishing different ageing levels of extra virgin olive oil is also presented. It shows effective potential for acting as a smart cap of bottled olive oil in order to achieve a non-destructive olfactory perception of oil ageing. Lastly, a compact portable fluorometer for the rapid monitoring of the carcinogenic M1 aflatoxin in milk, is experimented.

  13. Eat-by-light: fiber-optic and micro-optic devices for food safety and quality assessment

    NASA Astrophysics Data System (ADS)

    Mignani, A. G.; Ciaccheri, L.; Cucci, C.; Mencaglia, A. A.; Cimato, A.; Attilio, C.; Thienpont, H.; Ottevaere, H.; Paolesse, R.; Mastroianni, M.; Monti, D.; Buonocore, G.; Del Nobile, A.; Mentana, A.; Dall'Asta, C.; Faccini, A.; Galaverna, G.; Dossena, A.

    2007-07-01

    A selection of fiber-optic and micro-optic devices is presented designed and tested for monitoring the quality and safety of typical foods, namely the extra virgin olive oil, the beer, and the milk. Scattered colorimetry is used for the authentication of various types of extra virgin olive oil and beer, while a fiber-optic-based device for UV-VIS-NIR absorption spectroscopy is exploited in order to obtain the hyperspectral optical signature of olive oil. This is done not only for authentication purposes, but also so as to correlate the spectral data with the content of fatty acids that are important nutritional factors. A micro-optic sensor for the detection of olive oil aroma is presented. It is capable of distinguishing different ageing levels of extra virgin olive oil. It shows effective potential for acting as a smart cap of bottled olive oil in order to achieve a non-destructive olfactory perception of oil ageing. Lastly, a compact portable fluorometer is experimented for the rapid monitoring of the carcinogenic M1 aflatoxin in milk.

  14. Spring bloom onset in the Nordic Seas

    NASA Astrophysics Data System (ADS)

    Mignot, A.; Ferrari, R.; Mork, K. A.

    2015-08-01

    The North Atlantic spring bloom is a massive annual growth event of marine phytoplankton, tiny free-floating algae that form the base of the ocean's food web and generates a large fraction of the global primary production of organic matter. The conditions that trigger the onset of the spring bloom in the Nordic Seas, at the northern edge of the North Atlantic, are studied using in-situ data from five bio-optical floats released above the Arctic Circle. It is often assumed that spring blooms start as soon as phytoplankton cells daily irradiance is sufficiently abundant that division rates exceed losses. The bio-optical float data instead suggest the tantalizing hypothesis that Nordic Seas blooms start when the photoperiod, the number of daily light hours experienced by phytoplankton, exceeds a critical value, independently of division rates. This bloom behavior may be explained by realizing that photosynthesis is impossible during polar nights and phytoplankton enters in a dormant stage in winter, only to be awaken by a photoperiodic trigger. While the first accumulation of biomass recorded by the bio-optical floats is consistent with the photoperiod hypothesis, it is possible that some biomass accumulation started before the critical photoperiod but at levels too low to be detected by the fluorometers. Thus more precise observations are needed to test the photoperiod hypothesis.

  15. Firefly Luciferase-Based Sequential Bioluminescence Resonance Energy Transfer (BRET)-Fluorescence Resonance Energy Transfer (FRET) Protease Assays.

    PubMed

    Branchini, Bruce

    2016-01-01

    We describe here the preparation of ratiometric luminescent probes that contain two well-separated emission peaks produced by a sequential bioluminescence resonance energy transfer (BRET)-fluorescence resonance energy transfer (FRET) process. The probes are single soluble fusion proteins consisting of a thermostable firefly luciferase variant that catalyzes yellow-green (560 nm maximum) bioluminescence and a red fluorescent protein covalently labeled with a near-Infrared fluorescent dye. The two proteins are connected by a decapeptide containing a protease recognition site specific for factor Xa, thrombin, or caspase 3. The rates of protease cleavage of the fusion protein substrates were monitored by recording emission spectra and plotting the change in peak ratios over time. Detection limits of 0.41 nM for caspase 3, 1.0 nM for thrombin, and 58 nM for factor Xa were realized with a scanning fluorometer. This method successfully employs an efficient sequential BRET-FRET energy transfer process based on firefly luciferase bioluminescence to assay physiologically important protease activities and should be generally applicable to the measurement of any endoprotease lacking accessible cysteine residues.

  16. Shelf export of particulates/transport in continental margin waters

    SciTech Connect

    Pietrafesa, L.J.

    1991-02-01

    SEEP-II is a sponsored multi-institutional, multi-disciplinary program designed to address the possibility of flux material along and across the MAB. The methodology in SEEP-II employed conventional taut-wire moorings surrounding four RD acoustic doppler profiling current meters along with biological sampling of the source term of the biogenic material and the geochemical measurement of sedimentation rates. The field program was 17 months in length, from February 1988--June 1989, located off the Delaware and Chesapeake Bays. The SEEP-II moored array consists of two main cross-shelf arrays the northern of which had 6 to 8 moorings spanning the 40 to 1,000 m isobaths with one (and in Phase 2, a second) mooring offset about 20 km downshelf at 90m (and in Phase 2, a mooring also at 40m). The basic schematics of the northern and southern arrays are shown. In the region where the MAB shelf water/slope water front intersects the bottom, four RD-ADCP's were the focus of the array. Each of the bottom mounted profilers was accompanied by thermister strings (chains), Aanderaa current meters, fluorometers and transmissometers. 21 figs., 4 tabs.

  17. What limits photosynthetic energy conversion efficiency in nature? Lessons from the oceans.

    PubMed

    Falkowski, Paul G; Lin, Hanzhi; Gorbunov, Maxim Y

    2017-09-26

    Constraining photosynthetic energy conversion efficiency in nature is challenging. In principle, two yield measurements must be made simultaneously: photochemistry, fluorescence and/or thermal dissipation. We constructed two different, extremely sensitive and precise active fluorometers: one measures the quantum yield of photochemistry from changes in variable fluorescence, the other measures fluorescence lifetimes in the picosecond time domain. By deploying the pair of instruments on eight transoceanic cruises over six years, we obtained over 200 000 measurements of fluorescence yields and lifetimes from surface waters in five ocean basins. Our results revealed that the average quantum yield of photochemistry was approximately 0.35 while the average quantum yield of fluorescence was approximately 0.07. Thus, closure on the energy budget suggests that, on average, approximately 58% of the photons absorbed by phytoplankton in the world oceans are dissipated as heat. This extraordinary inefficiency is associated with the paucity of nutrients in the upper ocean, especially dissolved inorganic nitrogen and iron. Our results strongly suggest that, in nature, most of the time, most of the phytoplankton community operates at approximately half of its maximal photosynthetic energy conversion efficiency because nutrients limit the synthesis or function of essential components in the photosynthetic apparatus.This article is part of the themed issue 'Enhancing photosynthesis in crop plants: targets for improvement'. © 2017 The Author(s).

  18. The Solar Action Spectrum of Photosystem II Damage1[W][OA

    PubMed Central

    Takahashi, Shunichi; Milward, Sara E.; Yamori, Wataru; Evans, John R.; Hillier, Warwick; Badger, Murray R.

    2010-01-01

    The production of oxygen and the supply of energy for life on earth rely on the process of photosynthesis using sunlight. Paradoxically, sunlight damages the photosynthetic machinery, primarily photosystem II (PSII), leading to photoinhibition and loss of plant performance. However, there is uncertainty about which wavelengths are most damaging to PSII under sunlight. In this work we examined this in a simple experiment where Arabidopsis (Arabidopsis thaliana) leaves were exposed to different wavelengths of sunlight by dispersing the solar radiation across the surface of the leaf via a prism. To isolate only the process of photodamage, the repair of photodamaged PSII was inhibited by infiltration of chloramphenicol into the exposed leaves. The extent of photodamage was then measured as the decrease in the maximum quantum yield of PSII using an imaging pulse amplitude modulation fluorometer. Under the experimental light conditions, photodamage to PSII occurred most strongly in regions exposed to ultraviolet (UV) or yellow light. The extent of UV photodamage under incident sunlight would be greater than we observed when one corrects for the optical efficiency of our system. Our results suggest that photodamage to PSII under sunlight is primarily associated with UV rather than photosynthetically active light wavelengths. PMID:20460581

  19. Effect of essential oils on the growth of Fusarium verticillioides and fumonisin contamination in corn.

    PubMed

    Fandohan, Pascal; Gbenou, Joachim D; Gnonlonfin, Benoit; Hell, Kerstin; Marasas, Walter F O; Wingfield, Michael J

    2004-11-03

    Essential oils extracted by hydrodistillation from local plants in Benin, western Africa, and oil from seeds of the neem tree (Azadirachta indica) were evaluated in vitro and in vivo for their efficacy against Fusarium verticillioides infection and fumonisin contamination. Fumonisin in corn was quantified using a fluorometer and the Vicam method. Oils from Cymbopogon citratus, Ocimum basilicum, and Ocimum gratissimum were the most effective in vitro, completely inhibiting the growth of F. verticillioides at lower concentrations over 21 days of incubation. These oils reduced the incidence of F. verticillioides in corn and totally inhibited fungal growth at concentrations of 8, 6.4, and 4.8 microL/g, respectively, over 21 days. At the concentration of 4.8 microL/g, these oils did not affect significantly fumonisin production. However, a marked reduction of fumonisin level was observed in corn stored in closed conditions. The oils adversely affected kernel germination at 4.8 microL/g and therefore cannot be recommended for controlling F. verticillioides on stored corn used as seeds, when used at this concentration. The oil of neem seeds showed no inhibitory effect but rather accelerated the growth of F. verticillioides.

  20. A new class of nontoxic nanoparticle tags based on surface enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Qian, X.-M.; Ansari, D.; Nie, Shuming

    2007-02-01

    The advance of nanotechnology has boosted the development of ultra-sensitive biosensors for biomedical applications. Most recently, optical detection based biosensors have been demonstrated in medical imaging and diagnosis employing nanocrystals such as fluorescent quantum dots (QDs) and plasmon resonant metal nanoparticles to achieve femto-molar detection. An intriguing but far less explored approach for biological diagnostics relies on an emerging ultrasensitive technology -- surface enhanced Raman scattering (SERS) spectroscopy. We have developed a stable SERS nano-tag by grafting hydrophilic polymer to gold nanoparticle-dye molecule complexes to preserve the spectral signature and fully control the aggregation states. The light-emitting power and scattered light of both QDs and SERS nano-tags have been recorded under the same experimental conditions using dark field microscope, fluorometer, and Raman instrument. A comparison in brightness, sensitivity level, and quantum efficiency between SERS nano-tags and near infrared (NIR) QDs has been assessed on both bulk colloidal solution and single particle measurements. Well-designed SERS nano-tags exhibit excellent advantages over NIR QDs.

  1. Sequential bioluminescence resonance energy transfer-fluorescence resonance energy transfer-based ratiometric protease assays with fusion proteins of firefly luciferase and red fluorescent protein.

    PubMed

    Branchini, Bruce R; Rosenberg, Justin C; Ablamsky, Danielle M; Taylor, Kelsey P; Southworth, Tara L; Linder, Samantha J

    2011-07-15

    We report here the preparation of ratiometric luminescent probes that contain two well-separated emission peaks produced by a sequential bioluminescence resonance energy transfer (BRET)-fluorescence resonance energy transfer (FRET) process. The probes are single soluble fusion proteins consisting of a thermostable firefly luciferase variant that catalyze yellow-green (560nm maximum) bioluminescence and a red fluorescent protein covalently labeled with a near-infrared fluorescent dye. The two proteins are connected by a decapeptide containing a protease recognition site specific for factor Xa, thrombin, or caspase 3. The rates of protease cleavage of the fusion protein substrates were monitored by recording emission spectra and plotting the change in peak ratios over time. Detection limits of 0.41nM for caspase 3, 1.0nM for thrombin, and 58nM for factor Xa were realized with a scanning fluorometer. Our results demonstrate for the first time that an efficient sequential BRET-FRET energy transfer process based on firefly luciferase bioluminescence can be employed to assay physiologically important protease activities. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Measurement of discharge using tracers

    USGS Publications Warehouse

    Kilpatrick, F.A.; Cobb, Ernest D.

    1985-01-01

    The development of fluorescent dyes and fluorometers that can measure these dyes at very low concentrations has made dye-dilution methods practical for measuring discharge. These methods are particularly useful for determining discharge under certain flow conditions that are unfavorable for current meter measurements. These include small streams, canals, and pipes where 1. Turbulence is excessive for current-meter measurement but conducive to good mixing. 2. Moving rocks and debris may damage instruments placed in the flow. 3. Cross-sectional areas or velocities are indeterminate or changing. 4. The flow is unsteady, such as the flow that exists with storm-runoff events on small streams and urban storm-sewer systems. 5. The flow is physically inaccessible or unsafe. From a practical standpoint, such methods are limited primarily to small streams, because of the excessively long channel-mixing lengths required for larger streams. Very good accuracy can be obtained provided that 1. Adequate mixing length and time are allowed. 2. Careful field and laboratory techniques are used. 3. Dye losses are not significant. This manual describes the slug-injection and constant-rate injection methods of performing tracer-dilution measurements. Emphasis is on the use of fluorescent dyes as tracers and the equipment, field methods, and laboratory procedures for performing such measurements. The tracer-velocity method is also briefly discussed.

  3. Effect of arsenic on reflectance spectra and chlorophyll fluorescence of aquatic plants.

    PubMed

    Iriel, Analia; Dundas, Gavin; Fernández Cirelli, Alicia; Lagorio, Maria G

    2015-01-01

    Arsenic pollution of groundwater is a serious problem in many regions of Latin America that causes severe risks to human health. As a consequence, non-destructive monitoring methodologies, sensitive to arsenic presence in the environment and able to perform a rapid screening of large polluted areas, are highly sought-after. Both chlorophyll - a fluorescence and reflectance of aquatic plants may be potential indicators to sense toxicity in water media. In this work, the effects of arsenic on the optical and photophysical properties of leaves of different aquatic plants (Vallisneria gigantea, Azolla filiculoides and Lemna minor) were evaluated. Reflectance spectra were recorded for the plant leaves from 300 to 2400 nm. The spectral distribution of the fluorescence was also studied and corrected for light re-absorption processes. Photosynthetic parameters (Fv/Fm and ΦPSII) were additionally calculated from the variable chlorophyll fluorescence recorded with a pulse amplitude modulated fluorometer. Fluorescence and reflectance properties for V. gigantea and A. filiculoides were sensitive to arsenic presence in contrast to the behaviour of L. minor. Observed changes in fluorescence spectra could be interpreted in terms of preferential damage in photosystem II. The quantum efficiency of photosystem II for the first two species was also affected, decreasing upon arsenic treatment. As a result of this research, V. gigantea and A. filiculoides were proposed as bioindicators of arsenic occurrence in aquatic media. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Fluorescence of Supported Phospholipid Bilayers Recorded in a Conventional Horizontal-Beam Spectrofluorometer.

    PubMed

    Kovrigina, Elizaveta A; Kovrigin, Evgenii L

    2016-03-01

    Supported phospholipid bilayers are a convenient model of cellular membranes in studies of membrane biophysics and protein-lipid interactions. Traditionally, supported lipid bilayers are formed on a flat surface of a glass slide to be observed through fluorescence microscopes. This paper describes a method to enable fluorescence detection from the supported lipid bilayers using standard horizontal-beam spectrofluorometers instead of the microscopes. In the proposed approach, the supported lipid bilayers are formed on the inner optical surfaces of the standard fluorescence microcell. To enable observation of the bilayer absorbed on the cell wall, the microcell is placed in a standard fluorometer cell holder and specifically oriented to expose the inner cell walls to both excitation and emission channels with a help of the custom cell adaptor. The signal intensity from supported bilayers doped with 1 % (mol) of rhodamine-labeled lipid in the standard 3-mm optical microcell was equivalent to fluorescence of the 70-80 nM reference solution of rhodamine recorded in a commercial microcell adaptor. Because no modifications to the instruments are required in this method, a variety of steady-state and time-domain fluorescence measurements of the supported phospholipid bilayers may be performed with the spectral resolution using standard horizontal-beam spectrofluorometers.

  5. Spectrophotometric determination of protein concentration.

    PubMed

    Simonian, Michael H

    2004-09-01

    This unit describes spectrophotometric and colorimetric methods for measuring the concentration of a sample protein in solution. Absorbance measured at 280 nm (A(280)) is used to calculate protein concentration by comparison with a standard curve or published absorptivity values for that protein (a(280)). Alternatively, absorbance measured at 205 nm (A(205)) is used to calculate the protein concentration. The A(280) and A(205) methods can be used to quantify total protein in crude lysates and purified or partially purified protein. A spectrofluorometer or a filter fluorometer can be used to measure the intrinsic fluorescence emission of a sample solution; this value is compared with the emissions from standard solutions to determine the sample concentration. The fluorescence emission method is used to quantify purified protein. This simple method is useful for dilute protein samples and can be completed in a short amount of time. There are two colorimetric methods: the Bradford colorimetric method, based upon binding of the dye Coomassie brilliant blue to the protein of interest, and the Lowry method, which measures colorimetric reaction of tyrosyl residues in the protein sample.

  6. High frequency sampling of the 1984 spring bloom within the mid-Atlantic Bight: Synoptic shipboard, aircraft, and in situ perspectives of the SEEP-I experiment

    NASA Technical Reports Server (NTRS)

    Walsh, J. J.; Wirick, C. D.; Pietrafesa, L. J.; Whitledge, T. E.; Hoge, F. E.; Swift, R. N.

    1986-01-01

    Moorings of current meters, thermistors, transmissometers, and fluorometers on the mid-Atlantic shelf, south of Long Island, suggest a cumulative seaward export of perhaps 0.35 g C/sq m/day between the 80 and 120 m isobaths during February-April 1984. Such a horizontal loss of algal carbon over the lower third of the water column would be 23 to 78% of the March-April 1984 primary production. This physical carbon loss is similar to daily grazing losses from zooplankton of 32-40% of the algal fixation of carbon. Metabolic demands of the benthos could be met by just the estimated fecal pellet flux, without direct consumption of algal carbon, while bacterioplankton needs could be served by excretory release of dissolved organic matter during photosynthesis. Sediment traps tethered 10 m off the bottom at the 120 m isobath and 50 m above the 500 m isobath caught as much as 0.16 to 0.26 g C /sq m/day during March-April 1984, in reasonable agreement with the flux estimated from the other moored instruments.

  7. Potential use of ground-based sensor technologies for weed detection.

    PubMed

    Peteinatos, Gerassimos G; Weis, Martin; Andújar, Dionisio; Rueda Ayala, Victor; Gerhards, Roland

    2014-02-01

    Site-specific weed management is the part of precision agriculture (PA) that tries to effectively control weed infestations with the least economical and environmental burdens. This can be achieved with the aid of ground-based or near-range sensors in combination with decision rules and precise application technologies. Near-range sensor technologies, developed for mounting on a vehicle, have been emerging for PA applications during the last three decades. These technologies focus on identifying plants and measuring their physiological status with the aid of their spectral and morphological characteristics. Cameras, spectrometers, fluorometers and distance sensors are the most prominent sensors for PA applications. The objective of this article is to describe-ground based sensors that have the potential to be used for weed detection and measurement of weed infestation level. An overview of current sensor systems is presented, describing their concepts, results that have been achieved, already utilized commercial systems and problems that persist. A perspective for the development of these sensors is given.

  8. Modification and Single-Laboratory Validation of AOAC Official Method 977.13 for Histamine in Seafood to Improve Sample Throughput.

    PubMed

    Bjornsdottir-Butler, Kristin; Bencsath, F Aladar; Benner, Ronald A

    2015-01-01

    Histamine is the main causative agent in scombrotoxin fish poisoning, the most frequently reported illness related to fish consumption. The AOAC official method for histamine determination in fish is the fluorometric method AOAC 977.13, which is sensitive and reproducible but somewhat labor intensive and time consuming. We investigated multiple modifications to this method in an attempt to reduce assay time and increase sample throughput while maintaining the performance of the original method. Some of the attempted modifications negatively affected the performance characteristics of the method. However, omitting the heating step during extraction and replacing the cuvette style fluorometer with a microplate reader retained method performance while increasing sample throughput. Therefore, we adopted these modifications and conducted a single-laboratory validation. The recovery, precision (RSD), and LOD of the modified method assessed by the single-laboratory validation ranged from 92 to 105%, 1 to 3%, and 0.2 to 0.5 ppm, respectively, in tuna, mahi-mahi, and Spanish mackerel samples. We conclude that the AOAC 977.13 fluorometric method, modified as described, will improve assay time and sample throughput efficiency cumulatively, as the number of sample units analyzed increases. We anticipate that this modified method could be used by regulatory agencies and other laboratories following successful multilaboratory validation.

  9. Optical sensor for rapid microbial detection

    NASA Astrophysics Data System (ADS)

    Al-Adhami, Mustafa; Tilahun, Dagmawi; Rao, Govind; Kostov, Yordan

    2016-05-01

    In biotechnology, the ability to instantly detect contaminants is key to running a reliable bioprocess. Bioprocesses are prone to be contaminated by cells that are abundant in our environment; detection and quantification of these cells would aid in the preservation of the bioprocess product. This paper discusses the design and development of a portable kinetics fluorometer which acts as a single-excitation, single-emission photometer that continuously measures fluorescence intensity of an indicator dye, and plots it. Resazurin is used as an indicator dye since the viable contaminant cells reduce Resazurin toResorufin, the latter being strongly fluorescent. A photodiode detects fluorescence change by generating current proportional to the intensity of the light that reached it, and a trans-impedance differential op-amp ensures amplification of the photodiodes' signal. A microfluidic chip was designed specifically for the device. It acts as a fully enclosed cuvette, which enhances the Resazurin reduction rate. E. coli in LB media, along with Resazurin were injected into the microfluidic chip. The optical sensor detected the presence of E. coli in the media based on the fluorescence change that occurred in the indicator dye in concentrations as low as 10 CFU/ml. A method was devised to detect and determine an approximate amount of contamination with this device. This paper discusses application of this method to detect and estimate sample contamination. This device provides fast, accurate, and inexpensive means to optically detect the presence of viable cells.

  10. Production of volatile organic compounds by cyanobacteria Synechococcus sp.

    NASA Astrophysics Data System (ADS)

    Hiraiwa, M.; Abe, M.; Hashimoto, S.

    2014-12-01

    Phytoplankton are known to produce volatile organic compounds (VOCs), which contribute to environmental problems such as global warming and decomposition of stratospheric ozone. For example, picophytoplankton, such as Prochlorococcus and Synechococcus, are distributed in freshwater and oceans worldwide, accounting for a large proportion of biomass and primary production in the open ocean. However, to date, little is known about the production of VOCs by picophytoplankton. In this study, VOCs production by cyanobacteria Synechococcus sp. (NIES-981) was investigated. Synechococcus sp. was obtained from the National Institute for Environmental Studies (NIES), Japan, and cultured at 24°C in autoclaved f/2-Si medium under 54 ± 3 µE m-2 s-1 (1 E = 1 mol of photons) with a 12-h light and 12-h dark cycle. VOCs concentrations were determined using a purge-and-trap gas chromatograph-mass spectrometer (Agilent 5973). The concentrations of chlorophyll a (Chl a) were also determined using a fluorometer (Turner TD-700). Bromomethane (CH3Br) and isoprene were produced by Synechococcus sp. Isoprene production was similar to those of other phytoplankton species reported earlier. Isoprene was produced when Chl a was increasing in the early stage of the incubation period (5-15 days of incubation time, exponential phase), but CH3Br was produced when Chl a was reduced in the late stage of the incubation period (30-40 days of incubation time, death phase).

  11. Fast repetition rate (FRR) fluorometry: variability of chlorophyll a fluorescence yields in colonies of the corals, Montastraea faveolata (w.) and Diploria labyrinthiformes (h.) recovering from bleaching.

    PubMed

    Lombardi; Lesser; Gorbunov

    2000-09-05

    Recently, an underwater version of a fast repetition rate fluorometer (FRRF) was developed for the non-destructive study of fluorescence yields in benthic photoautotrophs. We used an FRRF to study bleached colonies of the corals, Montastraea faveolata and Diploria labyrinthiformes at sites surrounding Lee Stocking Island, Exuma, Bahamas, to assess their recovery from bleaching ( approximately 1 year after the initial bleaching event) induced by elevated temperatures. The steady state quantum yields of chlorophyll a fluorescence (DeltaF'/F'(m)) from photosystem II (PSII) within coral colonies were separated into three categories representing visibly distinct degrees of bleaching ranging from no bleaching to completely bleached areas. Differences in DeltaF'/F'(m) were significantly different from bleached to unbleached regions within colonies. Dark, unbleached regions within colonies exhibited significantly higher DeltaF'/F'(m) values (0.438+/-0.019; mean+/-S.D.) when compared to lighter regions, and occupied a majority of the colonies' surface area (46-73%). Bleached regions exhibited significantly lower DeltaF'/F'(m) (0.337+/-0.014) and covered only 7-25% of the colonies' surface area. The observations from this study suggest that zooxanthellae in bleached regions of a colony exhibit reduced photosynthetic activity as long as one year after a bleaching event and that in situ fluorescence techniques such as FRRF are an effective means of studying coral responses and recovery from natural or anthropogenic stress in a non-destructive manner.

  12. Application of a microplate scale fluorochrome staining assay for the assessment of viability of probiotic preparations.

    PubMed

    Alakomi, H-L; Mättö, J; Virkajärvi, I; Saarela, M

    2005-07-01

    Cell viability in probiotic preparations is traditionally assessed by the plate count technique. Additionally, fluorescent staining combined with epifluorescence microscopy or flow cytometry has been developed for the viability assessment, but the currently available assays are either laborious or require highly sophisticated equipment. The aim of this study was to investigate the applicability of a microplate scale fluorochrome assay for predicting the cell state of freeze-dried Lactobacillus rhamnosus and Bifidobacterium animalis subsp. lactis preparations. In addition to viability assessment with LIVE/DEAD BacLight Bacterial Viability Kit, DiBAC(4)3 stain was used for the kinetic measurement of changes in bifidobacterial cell membrane functions during exposure to low pH. The microplate scale fluorochrome assay results on the viability and cell numbers of probiotic preparations correlated well with the results obtained with the culture-based technique and (with few exceptions) with epifluorescence microscopy. The assay was applicable also for the viability assessment of stressed (acid-treated) cells provided that the cell density in treatments was adjusted to the optimal measurement level of the fluorometer. The microplate scale fluorochrome assay offers a rapid and robust tool for the viability assessment of probiotic preparations, and enables also kinetic measurements.

  13. Moorable spectroradiometers in the BIOWATT experiment

    NASA Technical Reports Server (NTRS)

    Booth, C. R.; Smith, R. C.

    1988-01-01

    A new oceanographic instrument, the MER-2020, has been developed for the long term measurement of bio-optical properties. This instrument is a self-contained reflectance spectroradiometer with 40 megabytes of internal data storage and battery power permitting deployments for as long as 6 months. It can serve as the control and recording center for a variety of other sensors including fluorometers, transmissometers, temperature and conductivity probes. Instruments of this type were deployed at depths to 70 meters on a 5000 meter mooring during the BIOWATT experiment between February and November 1987. Measurements of the spectral diffuse attenuation coefficient and of the remote sensed reflectance from the ten month period in 1987 in the Northern Sargasso Sea are presented. In addition, the temperature, pressure, package orientation and sunlight stimulated natural fluorescence of phytoplankton are discussed. This instrument will be a key part of in situ optical calibration for future remote color sensors, and presently permits direct measurement of long term optical variability, important in visibility and communication problems.

  14. Improved sensitivity for solid-support invasive cleavage reactions with flow cytometry analysis.

    PubMed

    Stevens, P Wilkins; Rao, K V N; Hall, J G; Lyamichev, V; Neri, B P; Kelso, D M

    2003-01-01

    A new configuration of the solid-support invasive cleavage reaction provides a small reaction-volume format for high-sensitivity discrimination of nucleic acid targets with single nucleotide differences. With target concentrations as low as 2 amol/assay, the solid-support invasive cleavage reaction clearly distinguishes single base mutations. Two oligonucleotides tethered to the solid support hybridize to the target nucleic acid, forming a tripartite substrate that can be recognized and cleaved by Cleavase, a structure-specific 5'-nuclease. Each cleavage event yields fluorescence signal on the surface. When microspheres serve as the solid-support surface, analysis by fluorometer imparts real-time information about change in the reaction signal over time. Flow cytometry provides an alternative detection technology that collects endpoint information about the reaction signal on individual microspheres. A reaction volume of 10 microL with as few as 3000 microspheres is sufficient to distinguish single nucleotide differences at target concentrations less than 200 fM. This sensitivity level is within the range required for analysis of SNPs in genomic DNA. In addition, the flow cytometry format has multiplexing potential, making the microsphere-based invasive cleavage assay attractive for high-throughput genomic applications.

  15. Carbon transport in the bottom boundary layer. Final report

    SciTech Connect

    Lohrenz, S.E.; Asper, V.L.

    1997-09-01

    The authors objective was to characterize distributions of chloropigment fluorescence in relation to physical processes in the benthic boundary layer in support of the Department of Energy (DOE) Ocean Margins Program`s (OMP) goal of quantifying carbon transport across the continental shelf. Their approach involved participation in the Ocean Margins Program (OMP) field experiment on the continental shelf off Cape Hatteras by conducting multi-sensor fluorescence measurements of photosynthetic pigments. Specific tasks included (1) pre- and post-deployment calibration of multiple fluorescence sensors in conjunction with Woods Hole personnel; (2) collection and analysis of photosynthetic pigment concentrations and total particulate carbon in water column samples to aid in interpretation of the fluorescence time-series during the field experiment; (3) collaboration in the analysis and interpretation of 1994 and 1996 time-series data in support of efforts to quantify pigment and particulate organic carbon transport on the continental shelf off Cape Hatteras. This third component included analysis of data obtained with a multi-sensor fiber-optic fluorometer in the benthic boundary layer of the inner shelf off Cape Hatteras during summer 1994.

  16. Effects of exercise training and detraining on cutaneous microvascular function in man: the regulatory role of endothelium-dependent dilation in skin vasculature.

    PubMed

    Wang, Jong-Shyan

    2005-01-01

    This study investigated how exercise training and detraining affect the cutaneous microvascular function and the regulatory role of endothelium-dependent dilation in skin vasculature. Ten healthy sedentary subjects cycled on an ergometer at 50% of maximal oxygen uptake (VO(2max)) for 30 min daily, 5 days a week, for 8 weeks, and then detrained for 8 weeks. Plasma nitric oxide (NO) metabolites (nitrite plus nitrate) were measured by a microplate fluorometer. The cutaneous microvascular perfusion responses to six graded levels of iontophoretically applied 1% acetylcholine (ACh) and 1% sodium nitroprusside (SNP) in the forearm skin were determined by laser Doppler. After training, (1) resting heart rate and blood pressure were reduced, whereas VO(2max), skin blood flow and cutaneous vascular conductance to acute exercise were enhanced; (2) plasma NO metabolite levels and ACh-induced cutaneous perfusion were increased; (3) skin vascular responses to SNP did not change significantly. However, detraining reversed these effects on cutaneous microvascular function and plasma NO metabolite levels. The results suggest that endothelium-dependent dilation in skin vasculature is enhanced by moderate exercise training and reversed to the pretraining state with detraining.

  17. Time of travel and dispersion of solutes in a 36.4-mile reach of the North Platte River downstream from Casper, Wyoming

    USGS Publications Warehouse

    Armentrout, G.W.; Larson, L.R.

    1984-01-01

    Time-of-travel and dispersion measurements made during a dye study November 7-8, 1978, are presented for a reach of the North Platte River from Casper, Wyo., to a bridge 2 miles downstream from below the Dave Johnston Power Plant. Rhodamine WT dye was injected into the river at Casper, and the resultant dye cloud was traced by sampling as it moved downstream. Samples were taken in three equal-flow sections of the river 's lateral transect at three sites, then analyzed in a fluorometer. The flow in the river was 940 cubic feet per second. The data consist of measured stream mileages and time, distance, and concentration graphs of the dye cloud. The peak concentration traveled through the reach in 24 hours, averaging 1.5 miles per hour; the leading edge took about 22 hours, averaging 1.7 miles per hour; and the trailing edge took 35 hours, averaging 1.0 mile per hour. Data from this study were compared with methods for estimating time of travel for a range of stream discharges.

  18. Optimized Detection of Plasmodium falciparum Topoisomerase I Enzyme Activity in a Complex Biological Sample by the Use of Molecular Beacons

    PubMed Central

    Givskov, Asger; Kristoffersen, Emil L.; Vandsø, Kamilla; Ho, Yi-Ping; Stougaard, Magnus; Knudsen, Birgitta R.

    2016-01-01

    The so-called Rolling Circle Amplification allows for amplification of circular DNA structures in a manner that can be detected in real-time using nucleotide-based molecular beacons that unfold upon recognition of the DNA product, which is being produced during the amplification process. The unfolding of the molecular beacons results in a fluorescence increase as the Rolling Circle Amplification proceeds. This can be measured in a fluorometer. In the current study, we have investigated the possibility of using two different molecular beacons to detect two distinct Rolling Circle Amplification reactions proceeding simultaneously and in the same reaction tube by measurement of fluorescence over time. We demonstrate the application of this fluorometric readout method, for automated and specific detection of the activity of the type IB topoisomerase from the malaria parasite Plasmodium falciparum in the presence of human cell extract containing the related topoisomerase I from humans. The obtained results point towards a future use of the presented assay setup for malaria diagnostics or drug screening purposes. In longer terms the method may be applied more broadly for real-time sensing of various Rolling Circle Amplification reactions. PMID:27854277

  19. SeaWiFS technical report series. Volume 32: Level-3 SeaWiFS data products. Spatial and temporal binning algorithms

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Acker, James G. (Editor); Campbell, Janet W.; Blaisdell, John M.; Darzi, Michael

    1995-01-01

    The level-3 data products from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) are statistical data sets derived from level-2 data. Each data set will be based on a fixed global grid of equal-area bins that are approximately 9 x 9 sq km. Statistics available for each bin include the sum and sum of squares of the natural logarithm of derived level-2 geophysical variables where sums are accumulated over a binning period. Operationally, products with binning periods of 1 day, 8 days, 1 month, and 1 year will be produced and archived. From these accumulated values and for each bin, estimates of the mean, standard deviation, median, and mode may be derived for each geophysical variable. This report contains two major parts: the first (Section 2) is intended as a users' guide for level-3 SeaWiFS data products. It contains an overview of level-0 to level-3 data processing, a discussion of important statistical considerations when using level-3 data, and details of how to use the level-3 data. The second part (Section 3) presents a comparative statistical study of several binning algorithms based on CZCS and moored fluorometer data. The operational binning algorithms were selected based on the results of this study.

  20. Molecular diagnostics in a teacup: Non-Instrumented Nucleic Acid Amplification (NINA) for rapid, low cost detection of Salmonella enterica

    PubMed Central

    KUBOTA, Ryo; LABARRE, Paul; WEIGL, Bernhard H; LI, Yong; HAYDOCK, Paul; JENKINS, Daniel M

    2014-01-01

    We report on the use of a novel non-instrumented platform to enable a Loop Mediated isothermal Amplification (LAMP) based assay for Salmonella enterica. Heat energy is provided by addition of a small amount (<150 g) of boiling water, and the reaction temperature is regulated by storing latent energy at the melting temperature of a lipid-based engineered phase change material. Endpoint classification of the reaction is achieved without opening the reaction tube by observing the fluorescence of sequence-specific FRET-based assimilating probes with a simple handheld fluorometer. At or above 22°C ambient temperature the non-instrumented devices could maintain reactions above a threshold temperature of 61°C for over 90 min—significantly longer than the 60 min reaction time. Using the simple format, detection limits were less than 20 genome copies for reactions run at ambient temperatures ranging from 8 to 36°C. When used with a pre-enrichment step and non-instrumented DNA extraction device, trace contaminations of Salmonella in milk close to 1 CFU/mL could be reliably detected. These findings illustrate that the non- instrumented amplification approach is a simple, viable, low-cost alternative for field-based food and agricultural diagnostics or clinical applications in developing countries. PMID:25477717

  1. Fiber optic-based fluorescence detection system for in vivo studies of exogenous chromophore pharmacokinetics

    NASA Astrophysics Data System (ADS)

    Doiron, Daniel R.; Dunn, J. B.; Mitchell, W. L.; Dalton, Brian K.; Garbo, Greta M.; Warner, Jon A.

    1995-05-01

    The detection and quantification of the concentration of exogenous chromophores in-vivo by their fluorescence is complicated by many physical and geometrical parameters. Measurement of such signals is advantageous in determining the pharmacokinetics of photosensitizers such as those used in photodynamic therapy (PDT) or to assist in the diagnosis of tissue histological state. To overcome these difficulties a ratio based fiber optic contact fluorometer has been developed. This fluorescence detection system (FDS) uses the ratio of the fluorescence emission peak of the exogenous chromophore to that of endogenous chromophores, i.e. autofluorescence, to correct for a variety of parameters affecting the magnitude of the measured signals. By doing so it also minimizes the range of baseline measurements prior to exogenous drug injection, for various tissue types. Design of the FDS and results of its testing in animals and patients using the second generation photosensitizer Tin ethyletiopurpurin (SnET2) are presented. These results support the feasibility and usefulness of the Ratio FDS system.

  2. Diel Cycle of Photosynthetic Electron Transport and Fluorescence Characteristics in Natural Phytoplankton Communities.

    NASA Astrophysics Data System (ADS)

    Kolber, Z.; Klimov, D.

    2007-12-01

    Phytoplankton photosynthetic performance is strongly controlled by the daily irradiance cycle. The most pronounced effects are the photoinhibition of photosynthetic activity in the morning and noon hours, and the development of non-photochemical quenching throughout the day. These two effects are extensively investigated as they significantly diminish the daily production rates. Less obvious, but equally important are the daily changes in the kinetics of rate-limiting electron transport within Photosystem II and Photosystem I of the photosynthetic apparatus. Using a fast repetition rate (FRR) fluorometer operating in the continuous flow-through mode in the Eastern Tropical Pacific, we observed theses rates to decelerate by a factor of five during the night, but recovering to a full speed just before the dawn. We characterized the effects of these changes on the photosynthetic performance of phytoplankton by continuously recording the fast light curves (variable fluorescence versus irradiance relationship). Besides controlling photochemistry, these changes strongly affect the chlorophyll fluorescence yield, especially when measured with a multiple turnover excitation. We will discuss how the knowledge of these rate-limiting steps may improve the fluorescence-based estimates of photosynthesis and chlorophyll biomass.

  3. Photo-physiological variability in phytoplankton chlorophyll fluorescence and assessment of chlorophyll concentration.

    PubMed

    Chekalyuk, Alexander; Hafez, Mark

    2011-11-07

    Photo-physiological variability of in vivo chlorophyll fluorescence (CF) per unit of chlorophyll concentration (CC) is analyzed using a biophysical model to improve the accuracy of CC assessments. Field measurements of CF and photosystem II (PSII) photochemical yield (PY) with the Advanced Laser Fluorometer (ALF) in the Delaware and Chesapeake Bays are analyzed vs. high-performance liquid chromatography (HPLC) CC retrievals. It is shown that isolation from ambient light, PSII saturating excitation, optimized phytoplankton exposure to excitation, and phytoplankton dark adaptation may provide accurate in vivo CC fluorescence measurements (R2 = 0.90-0.95 vs. HPLC retrievals). For in situ or flow-through measurements that do not allow for dark adaptation, concurrent PY measurements can be used to adjust for CF non-photochemical quenching (NPQ) and improve the accuracy of CC fluorescence assessments. Field evaluation has shown the NPQ-invariance of CF/PY and CF(PY-1-1) parameters and their high correlation with HPLC CC retrievals (R2 = 0.74-0.96), while the NPQ-affected CF measurements correlated poorly with CC (R2 = -0.22).

  4. Artemisinin induces caspase-8/9-mediated and Bax/Bak-independent apoptosis in human lung adenocarcinoma (ASTC-a-1) cells.

    PubMed

    Xiao, Feng-Lian; Gao, Wei-Jie; Liu, Cheng-Yi; Wang, Xiao-Ping; Chen, Tong-Sheng

    2011-01-01

    Artemisinin (ARTE), an antimalarial phytochemical component from the sweet wormwood plant, has been shown a potential anticancer activity by inducing cell apoptosis. The aim of this report is to explore the mechanism of ARTE-induced human lung adenocarcinoma (ASTC-a-1) cell apoptosis. Cell counting kit (CCK-8) assay showed that ARTE induced cytotoxcity in a dose- and time-dependent manner. Confocal microscopy fluorescence imaging of cells stained with Hoechst 33258 and flow cytometry (FCM) analysis of cells stained with Annexin V-FITC/propidium iodide (PI) showed that ARTE induced reactive oxygen species (ROS)-dependent apoptosis. Confocal fluorescence resonance energy transfer (FRET) imaging of single living cells expressing SCAT3, SCAT9 or CFP-Bid-YFP and fluorometic substrate assay showed that ARTE induced the activation of caspase-3, -8 and -9. Moreover, inhibition of caspase-8 or -9 completely blocked ARTE-induced apoptosis which was only partially attenuated by caspase-3 inhibitor. Interestingly, silencing Bax and Bak by RNA interference (RNAi) did not attenuate ARTE-induced apoptosis. Collectively, ARTE induces caspase-dependent but Bax/Bak-independent apoptosis in ASTC-a-1 cells.

  5. Peptide reactivity assay using spectrophotometric method for high-throughput screening of skin sensitization potential of chemical haptens.

    PubMed

    Jeong, Yun Hyeok; An, Susun; Shin, Kyeho; Lee, Tae Ryong

    2013-02-01

    Haptens must react with cellular proteins to be recognized by antigen presenting cells. Therefore, monitoring reactivity of chemicals with peptide/protein has been considered an in vitro skin sensitization testing method. The reactivity of peptides with chemicals (peptide reactivity) has usually been monitored by chromatographic methods like HPLC or LC/MS, which are robust tools for monitoring common chemical reactions but are rather expensive and time consuming. Here, we examined the possibility of using spectrophotometric methods to monitor peptide reactivity. Two synthetic peptides, Ac-RWAACAA and Ac-RWAAKAA, were reacted with 48 chemicals (34 sensitizers and 14 non-sensitizers). Peptide reactivity was measured by monitoring unreacted peptides with UV-Vis spectrophotometer using 5,5'-dithiobis-2-nitrobenzoic acid as a detection reagent for the free thiol group of cysteine-containing peptide or fluorometer using fluorescamine™ as a detection reagent for the free amine group of lysine-containing peptide. Chemicals were categorized as sensitizers when they induced more than 10% depletion of cysteine-containing peptide or 20% depletion of lysine-containing peptide. The sensitivity, specificity, and accuracy of this method were 82.4%, 85.7%, and 83.3%, respectively. These results demonstrate that spectrophotometric methods can be easy, fast, and high-throughput screening tools for the prediction of the skin sensitization potential of chemical haptens.

  6. Protocol Improvements for Low Concentration DNA-Based Bioaerosol Sampling and Analysis

    PubMed Central

    Ng, Chun Kiat; Miller, Dana; Cao, Bin

    2015-01-01

    Introduction As bioaerosol research attracts increasing attention, there is a need for additional efforts that focus on method development to deal with different environmental samples. Bioaerosol environmental samples typically have very low biomass concentrations in the air, which often leaves researchers with limited options in choosing the downstream analysis steps, especially when culture-independent methods are intended. Objectives This study investigates the impacts of three important factors that can influence the performance of culture-independent DNA-based analysis in dealing with bioaerosol environmental samples engaged in this study. The factors are: 1) enhanced high temperature sonication during DNA extraction; 2) effect of sampling duration on DNA recoverability; and 3) an alternative method for concentrating composite samples. In this study, DNA extracted from samples was analysed using the Qubit fluorometer (for direct total DNA measurement) and quantitative polymerase chain reaction (qPCR). Results and Findings The findings suggest that additional lysis from high temperature sonication is crucial: DNA yields from both high and low biomass samples increased up to 600% when the protocol included 30-min sonication at 65°C. Long air sampling duration on a filter media was shown to have a negative impact on DNA recoverability with up to 98% of DNA lost over a 20-h sampling period. Pooling DNA from separate samples during extraction was proven to be feasible with margins of error below 30%. PMID:26619279

  7. Real-time optical monitoring of tissue vitality in vivo

    NASA Astrophysics Data System (ADS)

    Mayevsky, Avraham; Manor, Tamar; Pevzner, Eliyahu; Deutsch, Assaf; Etziony, Revital; Dekel, Nava

    2002-03-01

    Evaluation of tissue O2 balance (Supply/Demand) could be done by monitoring in real-time 2 out of the 3 components of the tissue O2 balance equation. In our previous publication (Mayevsky et al, SPIE Vol. 4255:33-39, 2001) we had shown the use of the multiparametric monitoring approach in the neurosurgical operating room, using a device combined of laser Doppler flowmeter (LDF) and surface fluorometer reflectometer. The two instruments having two different light sources, were connected to the tissue via a combined bundle of optical fibers. In order to improve the correlation between tissue blood flow and mitochondrial NADH redox state, the new Tissue Spectroscope (TiSpec) that was designed has a single light source and a single bundle of optical fibers. Preliminary results show very clear correlation between TBF and NADH redox state. In addition, the reflected light at the excitation wavelength could be used as an indication for blood volume changes. The results obtained by the TiSpec enabled us to compare tissue O2 delivery (TBF) with O2 balance (NADH redox state) in the brain of gerbils and rats exposed to ischemia, anoxia and spreading depression. Real-time monitoring of the metabolic state of the tissue has immense potential during surgical procedures.

  8. Time-series observations of phytoplankton productivity in the western North Pacific by an underwater profiling buoy system

    NASA Astrophysics Data System (ADS)

    Fujiki, T.; Honda, M. C.; Matsumoto, K.; Kawakami, H.; Wakita, M.; Saino, T.; Marine Biogeochemical Cycle Research Team

    2010-12-01

    An understanding of the variability in phytoplankton primary productivity provides a basic knowledge of the ecosystem structure and carbon cycle in the ocean. Primary productivity in the world’s oceans has been measured mostly by the radiocarbon tracer or oxygen evolution methods. These methods require bottle incubations for periods ranging from hours to 1 day. This methodological limitation makes it difficult to measure primary productivity in situ with high temporal and spatial resolution. In particular, ship-based studies of the open ocean have been limited in their ability to conduct time-series observations for understanding variability in primary productivity. To overcome these problems, we developed an underwater profiling buoy system incorporating a fast repetition rate fluorometer which enables real-time high-frequency measurements of primary productivity, and started time-series observations in the western North Pacific as part of the environmental biogeochemical cycle research program in JAMSTEC. Here, we show the results of observations in the western North Pacific by the underwater profiling buoy system.

  9. Evaluation of a fluorometric method for measuring low concentrations of ammonia in ambient air.

    PubMed

    Groves, William A; Agarwal, Divya; Chandra, M Jeya; Reynolds, Stephen J

    2005-02-01

    A fluorometric method developed for measuring low concentrations of ammonium in marine and freshwater ecosystems was adapted for the analysis of ammonia in ambient air. The modified method entails collection of samples on an acid-treated solid adsorbent followed by analysis using a fluorometer. Optimal results were obtained using a commercially available sorbent tube containing 100 mg of acid-treated silica gel for sample collection, and an analytical protocol consisting of sample desorption in DI water, addition of orthopthaldialdehyde (OPA) working reagent, and room temperature incubation. Method accuracy and precision were evaluated by comparing experimentally determined quantities of ammonia to expected levels for sample loadings ranging from 0.16 [micro sign]g to 550 [micro sign]g-accuracy was generally within +/-20%. The estimated LOQ for the method is 0.08 [micro sign]g ammonia per sample which represents a 25-375-fold improvement in sensitivity compared to current NIOSH and OSHA methods for the measurement of ammonia in ambient air. The new method should be useful for applications requiring measurement of low concentrations of ammonia using personal sampling equipment or in the characterization of short-term fluctuations of ammonia concentrations in air.

  10. Panax ginseng induces the expression of CatSper genes and sperm hyperactivation

    PubMed Central

    Park, Eun Hwa; Kim, Do Rim; Kim, Ha Young; Park, Seong Kyu; Chang, Mun Seog

    2014-01-01

    The cation channel of sperm (CatSper) protein family plays important roles in male reproduction and infertility. The four members of this family are expressed exclusively in the testis and are localized differently in sperm. To investigate the effects of Panax ginseng treatment on the expression of CatSper genes and sperm hyperactivation in male mice, sperm motility and CatSper gene expression were assessed using a computer-assisted semen analysis system, a Fluoroskan Ascent microplate fluorometer to assess Ca2+ influx, real-time polymerase chain reaction, Western blotting and immunofluorescence. The results suggested that the Ca2+ levels of sperm cells treated with P. ginseng were increased significantly compared with the normal group. The P. ginseng-treated groups showed increased sperm motility parameters, such as the curvilinear velocity and amplitude of lateral head displacement. Taken together, the data suggest that CatSper messenger ribonucleic acid levels were increased significantly in mouse testes in the P. ginseng-treated group, as was the protein level, with the exception of CatSper2. In conclusion, P. ginseng plays an important role in improving sperm hyperactivation via CatSper gene expression. PMID:24969054

  11. SPATIAL HETEROGENEITY OF PHOTOSYNTHETIC ACTIVITY WITHIN DISEASED CORALS FROM THE GREAT BARRIER REEF(1).

    PubMed

    Roff, George; Ulstrup, Karin E; Fine, Maoz; Ralph, Peter J; Hoegh-Guldberg, Ove

    2008-04-01

    Morphological diagnosis and descriptions of seven disease-like syndromes affecting scleractinian corals were characterized from the southern Great Barrier Reef (GBR). Chl a fluorescence of PSII was measured using an Imaging-PAM (pulse amplitude modulated) fluorometer, enabling visualization of the two-dimensional variability in the photophysiology of endosymbiotic dinoflagellates (zooxanthellae) by measuring rapid light curves. Three of four syndromes associated with active tissue loss (type a) were spatially homogenous (white syndrome, brown band, and skeletal eroding band), with no impact on the photochemical function of zooxanthellae populations at or behind the lesion borders. However, a decline in maximum quantum yield (Fv /Fm ) and elevated levels of maximum nonphotochemical quenching (NPQmax ) occurred in visually healthy tissue of black band disease adjacent to the lesion borders, possibly due to hypoxic conditions caused by the black band cyanobacterial mat. Two out of three syndromes associated with pathological change of intact tissue with no active tissue loss (type b) showed variable photophysiological responses (neoplasia and pigmentation response). Only the bleached foci associated with white patch syndrome appeared to impact primarily on the symbiotic dinoflagellates, as evidenced by declines in minimum fluorescence (F0 ) and maximum quantum yield (Fv /Fm ), with no indication of degeneration in the host tissues. Our results suggest that for the majority of coral syndromes from the GBR, pathogenesis occurs in the host tissue, while the impact on the zooxanthellae populations residing in affected corals is minimal.

  12. The Use of Chlorophyll Fluorescence Lifetime to Assess Phytoplankton Physiology within a River-Dominated Environment

    NASA Technical Reports Server (NTRS)

    Hall, Callie M.; Miller, Richard L.; Redalje, Donald G.; Fernandez, Salvador M.

    2002-01-01

    Chlorophyll a fluorescence lifetime was measured for phytoplankton populations inhabiting the three physical zones surrounding the Mississippi River's terminus in the Gulf of Mexico. Observations of river discharge volume, nitrate + nitrite, silicate, phosphate, PAR (Photosynthetically Active Radiation) diffuse attenuation within the water column, salinity, temperature, SPM, and chl a concentration were used to characterize the distribution of chl fluorescence lifetime within a given region within restricted periods of time. 33 stations extending from the Mississippi River plume to the shelf break of the Louisiana coast were surveyed for analysis of chlorophyll fluorescence lifetime during two cruises conducted March 31 - April 6, 2000, and October 24 - November 1, 2000. At each station, two to three depths were chosen for fluorescence lifetime measurement to represent the vertical characteristics of the water column. Where possible, samples were taken from just below the surface and from just above and below the pycnocline. All samples collected were within the 1% light level of the water column (the euphotic zone). Upon collection, samples were transferred to amber Nalgene bottles and left in the dark for at least 15 minutes to reduce the effects of non-photochemical quenching and to insure that photosynthetic reaction centers were open. Before measurements within the phase fluorometer were begun, the instrument was allowed to warm up for no less than one hour.

  13. Determination of lithium in rocks: Fluorometric method

    USGS Publications Warehouse

    White, C.E.; Fletcher, M.H.; Parks, J.

    1951-01-01

    The gravimetric method in general use for the determination of lithium is tedious, and the final weighed product often contains other alkali metals. A fluorometric method was developed to shorten the time required for the analysis and to assure that the final determination is for lithium alone. This procedure is based on the complex formed between lithium and 8-hydroxyquinoline. The fluorescence is developed in a slightly alkaline solution of 95% alcohol and measurement is made on a photoelectric fluorometer. Separation from the ore is carried out by the wet method or by the distillation procedure. Sodium and potassium are removed by alcohol and ether, but complete separation is not necessary. Comparison of analyzed samples shows excellent agreement with spectrographic and gravimetric methods. The fluorometric method is more rapid than the gravimetric and produces more conclusive results. Another useful application is in the preparation of standard lithium solutions from reagent quality salts when a known standard is available. In this case no separations are necessary.

  14. Primary sites of ozone-induced perturbations of photosynthesis in leaves: identification and characterization in Phaseolus vulgaris using high resolution chlorophyll fluorescence imaging.

    PubMed

    Leipner, J; Oxborough, K; Baker, N R

    2001-08-01

    High resolution imaging of chlorophyll a fluorescence was used to identify the sites at which ozone initially induces perturbations of photosynthesis in leaves of Phaseolus vulgaris. Leaves were exposed to 250 and 500 nmol mol(-1) ozone at a photosynthetically active photon flux density of 300 micromol m(-2) s(-1) for 3 h. Images of fluorescence parameters indicated that large decreases in both the maximum and operating quantum efficiencies of photosystem II had occurred in cells adjacent to stomata in the upper, but not lower, leaf surfaces. However, this treatment did not produce any significant changes in the maximum or operating quantum efficiencies of photosystem II in the leaves when estimated from fluorescence parameters measured with a conventional, integrating fluorometer. The localized decreases in photosystem II photochemical efficiencies were accompanied by an increase in the minimal fluorescence level, which is indicative of photoinactivation of photosystem II complexes and a decrease in stomatal conductance. Perturbations of photochemical efficiencies were not observed in cells associated with all of the stomata on the upper leaf surface or within cells distant from the upper leaf surface. It is concluded that ozone penetrates the leaf through stomata and initially damages only cells close to stomatal pores.

  15. A new label technology for the detection of specific polymerase chain reaction products in a closed tube

    PubMed Central

    Nurmi, Jussi; Ylikoski, Alice; Soukka, Tero; Karp, Matti; Lövgren, Timo

    2000-01-01

    A novel signal generation principle suitable for real time and end-point detection of specific PCR products in a closed tube is described. Linear DNA probes were labeled at their 5′-ends with a stable, fluorescent terbium chelate. The fluorescence intensity of this chelate is lower when it is coupled to single-stranded DNA than when the chelate is free in solution. The synthesized probes were used in the real time monitoring of PCR using a prototype instrument that consisted of a fluorometer coupled to a thermal cycler. When the probe anneals to a complementary target amplicon, the 5′→3′ exonucleolytic activity of DNA polymerase detaches the label from the probe. This results in an enhanced terbium fluorescence signal. Since terbium has a long excited state lifetime, its fluorescence can be measured in a time-resolved manner, which results in a low background fluorescence and a 1000-fold signal amplification. The detection method is quantitative over an extremely wide linear range (at least 10–107 initial template molecules). The label strategy can easily be combined with existing label technologies, such as TaqMan 5′-exonuclease assays, in order to carry out multiplex assays that do not suffer from overlapping emission peaks of the fluorophores. PMID:10734205

  16. Multi-parametric relationships between PAM measurements and carbon incorporation, an in situ approach.

    PubMed

    Napoléon, Camille; Claquin, Pascal

    2012-01-01

    Primary production (PP) in the English Channel was measured using (13)C uptake and compared to the electron transport rate (ETR) measured using PAM (pulse amplitude modulated fluorometer). The relationship between carbon incorporation (P(obs)) and ETR was not linear but logarithmic. This result can be explained by alternative electron sinks at high irradiance which protect the phytoplankton from photoinhibition. A multi-parametric model was developed to estimate PP by ETR. This approach highlighted the importance of taking physicochemical parameters like incident light and nutrient concentrations into account. The variation in the ETR/P(obs) ratio as a function of the light revealed different trends which were characterized by three parameters (R(max), the maximum value of ETR/P(obs); E(Rmax), the light intensity at which R(max) is measured; γ the initial slope of the curve). Based on the values of these three parameters, data were divided into six groups which were highly dependent on the seasons and on the physicochemical conditions. Using the multi-parametric model which we defined by P(obs) and ETR measurements at low frequencies, the high frequency measurements of ETR enabled us to estimate the primary production capacity between November 2009 and December 2010 at high temporal and spatial scales.

  17. Multi-Parametric Relationships between PAM Measurements and Carbon Incorporation, an In Situ Approach

    PubMed Central

    Napoléon, Camille; Claquin, Pascal

    2012-01-01

    Primary production (PP) in the English Channel was measured using 13C uptake and compared to the electron transport rate (ETR) measured using PAM (pulse amplitude modulated fluorometer). The relationship between carbon incorporation (Pobs) and ETR was not linear but logarithmic. This result can be explained by alternative electron sinks at high irradiance which protect the phytoplankton from photoinhibition. A multi-parametric model was developed to estimate PP by ETR. This approach highlighted the importance of taking physicochemical parameters like incident light and nutrient concentrations into account. The variation in the ETR/Pobs ratio as a function of the light revealed different trends which were characterized by three parameters (Rmax, the maximum value of ETR/Pobs; ERmax, the light intensity at which Rmax is measured; γ the initial slope of the curve). Based on the values of these three parameters, data were divided into six groups which were highly dependent on the seasons and on the physicochemical conditions. Using the multi-parametric model which we defined by Pobs and ETR measurements at low frequencies, the high frequency measurements of ETR enabled us to estimate the primary production capacity between November 2009 and December 2010 at high temporal and spatial scales. PMID:22911698

  18. Satellite detection of phytoplankton export from the mid-Atlantic Bight during the 1979 spring bloom

    NASA Technical Reports Server (NTRS)

    Walsh, J. J.; Dieterle, D. A.; Esaias, W. E.

    1986-01-01

    Analysis of Coastal Zone Color Scanner (CZCS) imagery confirms shipboard and in situ moored fluorometer observations of resuspension of near-bottom chlorophyll within surface waters (1 to 10 m) by northwesterly wind events in the mid-Atlantic Bight. As much as 8 to 16 micrograms chl/l are found during these wind events from March to May, with a seasonal increase of algal biomass until onset of stratification of the water column. Rapid sinking or downwelling apparently occurs after subsequent wind events, however, such that the predominant surface chlorophyll pattern is approx. 0.5 to 1.5 micrograms/l over the continental shelf during most of the spring bloom. Perhaps half of the chlorophyll increase observed by satellite during a wind resuspension event represents in-situ production during the 4 to 5 day interval, with the remainder attributed to accumulation of algal biomass previously produced and temporarily stored within near-bottom water. Present calculations suggest that about 10% of the primary production of the spring bloom may be exported as ungrazed phytoplankton carbon from mid-Atlantic shelf waters to those of the continental slope.

  19. Development of loop-mediated isothermal amplification (LAMP) assay for rapid and sensitive identification of ostrich meat.

    PubMed

    Abdulmawjood, Amir; Grabowski, Nils; Fohler, Svenja; Kittler, Sophie; Nagengast, Helga; Klein, Guenter

    2014-01-01

    Animal species identification is one of the primary duties of official food control. Since ostrich meat is difficult to be differentiated macroscopically from beef, therefore new analytical methods are needed. To enforce labeling regulations for the authentication of ostrich meat, it might be of importance to develop and evaluate a rapid and reliable assay. In the present study, a loop-mediated isothermal amplification (LAMP) assay based on the cytochrome b gene of the mitochondrial DNA of the species Struthio camelus was developed. The LAMP assay was used in combination with a real-time fluorometer. The developed system allowed the detection of 0.01% ostrich meat products. In parallel, a direct swab method without nucleic acid extraction using the HYPLEX LPTV buffer was also evaluated. This rapid processing method allowed detection of ostrich meat without major incubation steps. In summary, the LAMP assay had excellent sensitivity and specificity for detecting ostrich meat and could provide a sampling-to-result identification-time of 15 to 20 minutes.

  20. Tissue characterization by time-resolved fluorescence spectroscopy of endogenous and exogenous fluorochromes: apparatus design and preliminary results

    NASA Astrophysics Data System (ADS)

    Glanzmann, Thomas M.; Ballini, Jean-Pierre; Jichlinski, Patrice; van den Bergh, Hubert; Wagnieres, Georges A.

    1996-12-01

    The biomedical use of an optical fiber-based spectro- temporal fluorometer that can endoscopically record the fluorescence decay of an entire spectrum without scanning is presented. The detector consists of a streak camera coupled to a spectrograph. A mode-locked argon ion pumped dye laser or a nitrogen laser-pumped dye laser are used as pulsed excitation light sources. We measured the fluorescence decays of endogenous fluorophores and of ALA-induced- protoporphyrin IX(PPIX) in an excised human bladder with a carcinoma in situ (CIS). Each autofluorescence decay can be decomposed in at least three exponential components for all tissue samples investigated if the excitation is at 425 nm. The decays of the autofluorescence of all normal sites of the human bladder are similar and they differ significantly from the decays measured on the CIS and the necrotic tissue. The fluorescence of the ALA-induced PPIX in the bladder is monoexponential with a lifetime of 15 (plus or minus 1) ns and this fluorescence lifetime does not change significantly between the normal urothelium and the CIS. A photoproduct of ALA-PPIX with a fluorescence maximum at 670 nm and a lifetime of 8 (plus or minus 1) ns was observed. The measurement of the decay of the autofluorescence allowed to correctly identify a normal tissue site that was classified as abnormal by the measurement of the ALA-PPIX fluorescence intensity.

  1. Quantification of algal biofilms colonising building materials: chlorophyll a measured by PAM-fluorometry as a biomass parameter.

    PubMed

    Eggert, A; Häubner, N; Klausch, S; Karsten, U; Schumann, R

    2006-01-01

    The aim of this study was to quantify algal colonisation on anthropogenic surfaces (viz. building facades and roof tiles) using chlorophyll a (chl a) as a specific biomarker. Chl a was estimated as the initial fluorescence F0 of 'dark adapted' algae using a pulse-modulated fluorometer (PAM-2000). Four isolates of aeroterrestrial green algae and one aquatic isolate were included in this study. The chl a concentration and F0 showed an exponential relationship in the tested range between 0 and 400 mg chl a m(-2). The relationship was linear at chl a concentrations <20 mg m(-2). Exponential and linear models are presented for the single isolates with large coefficients of determination (exponential: r2 > 0.94, linear: r2 > 0.92). The specific power of this fluorometric method is the detection of initial algal colonisation on surfaces in thin or young biofilms down to 3.5 mg chl a m(-2), which corresponds to an abundances of the investigated isolates between 0.2 and 1.5 million cells cm(-2).

  2. Time-Resolved Fluorometry Based Sandwich Hybridisation Assay for HLA-DQA1 Typing

    PubMed Central

    Sjöroos, Minna; Ilonen, Jorma; Reijonen, Helena; Lövgren, Timo

    1998-01-01

    A microtitration plate based time-resolved fluorescence (TRF) hybridisation assay was developed for HLA typing utilising biotinylated sequence-specific catching probes and europium (Eu) labelled gene locus-specific detection probe to allow time-resolved fluorometer reading of the reaction. In an application for HLA-DQA typing a 228 base pair long region of the polymorphic exon 2 of DQA1 gene was amplified and the denatured PCR product distributed into streptavidin-coated microtitration wells together with the detection probe and one of the catching probes. After incubation and washes, the enhancement solution was added and specific hybridisation signal detected by measuring the emitted light. A series of 100 isolated genomic DNA samples were studied using biotinylated probes specific for DQA1*01, *0101/0104, *0103/0201/0601, *0201, *03, *0401/0601, *05 and *0502 alleles with results demonstrating the capacity of the test to detect aimed alleles. A series of whole blood spot samples were also studied and the results confirmed the applicability of this modification of the test. PMID:9706458

  3. Production of terpenes in the culture of Chlorophyceae and Rhodophyta

    NASA Astrophysics Data System (ADS)

    Abe, M.; Hashimoto, S.

    2014-12-01

    Terpenes show high reactivity in the troposphere, contributing to organic aerosol reactions with OH radicals. One of the main sources of terpenes in the atmosphere is terrestrial plants. It has been recently reported that marine phytoplankton also produce monoterpenes (Yassaa et al: 2008). Because aerosol production of natural origin affects the cloud cover over the open ocean, it is important to investigate the origin of aerosol generation in the open ocean. In this study, we investigated the production of terpenes and isoprene with a focus on Chlamydomonas (Chlorophyceae) and Rhodella maculata (Rhodophyta). Concentrations of terpenes and isoprene were measured using a dynamic headspace (GERSTEL DHS)—gas chromatograph (Agilent 6890N)—mass spectrometer (Agilent 5975C). In addition, chlorophyll a was measured using a fluorometer (Turner TD-700). The results showed that isoprene, α-pinene, and β-pinene were produced by Chlamydomonas sp. and that isoprene, limonene, and camphene were produced by Rhodella maculata. Chlamydomonas sp. produced α-pinene and β-pinene, similar to land plants. The ratio of the pinene/isoprene concentrations in the atmosphere over seawater where phytoplankton are blooming has been reported as approximately 0.7 (Yassaa et al: 2008). In this experiment, the pinene/isoprene concentration ratios in the cultures were approximately 0.1. This result indicates that marine phytoplankton may not be ignored in the marine atmosphere chemistry of terpenes.

  4. Characterization of methods for determining sterilization efficacy and reuse efficiency of oxygen biosensor multiwell plates.

    PubMed

    Birmele, Michele; Roberts, Michael; Garland, Jay

    2006-12-01

    High-throughput screening (HTS) assays based upon fluorometric detection of oxygen consumption in microtiter plates were primarily developed for applications in drug discovery and ecotoxicology but have recently been adopted for use in microbial community-level physiological profiling assays (CLPP). The widespread use of oxygen biosensor systems for CLPP applications has, however, been hindered by the relatively high cost of oxygen biosensor reagent systems and limited access to microplate fluorometer instrumentation platforms. The ability to recycle and reuse oxygen biosensor system plates would expand their utilization for CLPP assays and other research applications in microbial ecology. Here, the efficacy and cost effectiveness of multiple procedures for sterilization of Oxygen Biosensor System (OBS; BD Biosciences) plates for reuse was evaluated. OBS plates were sterilized using ethylene oxide, ultraviolet radiation, and bleach treatments, then evaluated for biosensor response and plate life-cycle performance. Of the sterilization methods tested, ethylene oxide sterilization was most effective based on its low cost, high sterilization efficacy, and minimal impact upon OBS plate response.

  5. Imaging of chlorophyll a fluorescence: theoretical and practical aspects of an emerging technique for the monitoring of photosynthetic performance.

    PubMed

    Oxborough, Kevin

    2004-05-01

    The development of chlorophyll (Chl) a fluorescence imaging systems has greatly increased the versatility of Chl a fluorometry as a non-invasive technique for the investigation of photosynthesis in plants and algae. For example, systems that image at the microscopic level have made it possible to measure PSII photochemical efficiencies from chloroplasts within intact leaves and from individual algal cells within mixed populations, while systems that image over much larger areas have been used to investigate heterogeneous patterns of photosynthetic performance across leaves and in screening programmes that image tens or even hundreds of plants simultaneously. In addition, it is now practical to use fluorescence imaging systems as real-time, multi-channel fluorometers, which can be used to record continuous fluorescence traces from multiple leaves, plants, or algal cells. This paper discusses some of the theoretical and practical issues associated with the imaging of Chl a fluorescence and with Chl a fluorometry in general. This discussion includes a review of the most commonly used Chl a fluorescence parameters.

  6. Comparisons between transect and fixed point in a oceanic turbulent flow: statistical analyses

    NASA Astrophysics Data System (ADS)

    Koziol, Lucie; Schmitt, Francois G.; Artigas, Felipe; Lizon, Fabrice

    2016-04-01

    Oceanological processes possess important fluctuations over large ranges of spatial and temporal scales. These fluctuations are related with the turbulence of the ocean. Usually, in turbulence, one considers fixed point Eulerian measurements, or Lagrangian measurements following an elements of fluid. On the other hand, in oceanography, measurements are often done from a boat operating over a transect, where the boat is moving in the medium at a fixed speed (relative to the flow). Here the aim of our study is to consider if such moving reference frame is modifying the statistics of the measurements. For this we compare two type of measurements at high frequency: fixed point measurements, and transect measurements, where the boat is moving at a fixed speed relative to the flow. 1 Hz fluorometer measurements are considered in both cases. Measurements have been done the same day, under similar conditions. Power spectra of time series are considered, as well as local mean and variance measurements along each transect. It is found that the spectral scaling slope of the measurement is not modified, but the variance is very different, being much larger for the moving frame. Such result needs theoretical understanding and has potential important consequence regarding the measurement that are done at high frequency on moving frames in oceanography.

  7. Fluorometric determination of zirconium in minerals

    USGS Publications Warehouse

    Alford, W.C.; Shapiro, L.; White, C.E.

    1951-01-01

    The increasing use of zirconium in alloys and in the ceramics industry has created renewed interest in methods for its determination. It is a common constituent of many minerals, but is usually present in very small amounts. Published methods tend to be tedious, time-consuming, and uncertain as to accuracy. A new fluorometric procedure, which overcomes these objections to a large extent, is based on the blue fluorescence given by zirconium and flavonol in sulfuric acid solution. Hafnium is the only element that interferes. The sample is fused with borax glass and sodium carbonate and extracted with water. The residue is dissolved in sulfuric acid, made alkaline with sodium hydroxide to separate aluminum, and filtered. The precipitate is dissolved in sulfuric acid and electrolysed in a Melaven cell to remove iron. Flavonol is then added and the fluorescence intensity is measured with a photo-fluorometer. Analysis of seven standard mineral samples shows excellent results. The method is especially useful for minerals containing less than 0.25% zirconium oxide.

  8. Anserine inhibits carnosine degradation but in human serum carnosinase (CN1) is not correlated with histidine dipeptide concentration.

    PubMed

    Peters, Verena; Jansen, Erwin E W; Jakobs, Cornelis; Riedl, Eva; Janssen, Bart; Yard, Benito A; Wedel, Johannes; Hoffmann, Georg F; Zschocke, Johannes; Gotthardt, Daniel; Fischer, Christine; Köppel, Hannes

    2011-01-30

    We reported an association of a particular allele of the carnosinase (CNDP1 Mannheim) gene with reduced serum carnosinase (CN1) activity and absence of nephropathy in diabetic patients. Carnosine protects against the adverse effects of high glucose levels but serum carnosine concentration was generally low. We measured the concentration of two further histidine dipeptides, anserine and homocarnosine, via HPLC. CN1 activity was measured fluorometically and for concentration we developed a capture ELISA. We found an association between the CNDP1 Mannheim allele and reduced serum CN1 activity for all three dipeptides but no correlation to serum concentrations although anserine and homocarnosine inhibited carnosinase activity. Patients with liver cirrhosis have low CN1 activity (0.24 ± 0.17 μmol/ml/h, n=7 males; normal range: 3.2 ± 1.1, n=104; p<0.05) and CN1 concentrations (2.3 ± 1.5 μg/ml; normal range: 24.9 ± 8.9, p<0.05) but surprisingly, histidine dipeptide concentrations in serum are not increased compared to controls. Serum histidine dipeptide concentrations are not correlated to CN1 activity. The protective effect of low CN1 activity might be related either to turnover of CN1 substrates or a protective function of dipeptides might be localized in other tissues. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Cu(2+) inhibits photosystem II activities but enhances photosystem I quantum yield of Microcystis aeruginosa.

    PubMed

    Deng, Chunnuan; Pan, Xiangliang; Wang, Shuzhi; Zhang, Daoyong

    2014-08-01

    Responses of photosystem I and II activities of Microcystis aeruginosa to various concentrations of Cu(2+) were simultaneously examined using a Dual-PAM-100 fluorometer. Cell growth and contents of chlorophyll a were significantly inhibited by Cu(2+). Photosystem II activity [Y(II)] and electron transport [rETRmax(II)] were significantly altered by Cu(2+). The quantum yield of photosystem II [Y(II)] decreased by 29 % at 100 μg L(-1) Cu(2+) compared to control. On the contrary, photosystem I was stable under Cu(2+) stress and showed an obvious increase of quantum yield [Y(I)] and electron transport [rETRmax(I)] due to activation of cyclic electron flow (CEF). Yield of cyclic electron flow [Y(CEF)] was enhanced by 17 % at 100 μg L(-1) Cu(2+) compared to control. The contribution of linear electron flow to photosystem I [Y(II)/Y(I)] decreased with increasing Cu(2+) concentration. Yield of cyclic electron flow [Y(CEF)] was negatively correlated with the maximal photosystem II photochemical efficiency (F v/F m). In summary, photosystem II was the major target sites of toxicity of Cu(2+), while photosystem I activity was enhanced under Cu(2+) stress.

  10. SmartFluo: A Method and Affordable Adapter to Measure Chlorophyll a Fluorescence with Smartphones.

    PubMed

    Friedrichs, Anna; Busch, Julia Anke; van der Woerd, Hendrik Jan; Zielinski, Oliver

    2017-03-25

    In order to increase the monitoring capabilities of inland and coastal waters, there is a need for new, affordable, sensitive and mobile instruments that could be operated semi-automatically in the field. This paper presents a prototype device to measure chlorophyll a fluorescence: the SmartFluo. The device is a combination of a smartphone offering an intuitive operation interface and an adapter implying a cuvette holder, as well as a suitable illumination source. SmartFluo is based on stimulated fluorescence of water constituents such as chlorophyll a. The red band of the digital smartphone camera is sensitive enough to detect quantitatively the characteristic red fluorescence emission. The adapter contains a light source, a strong light emitting diode and additional filters to enhance the signal-to-noise ratio and to suppress the impact of scattering. A novel algorithm utilizing the red band of the camera is provided. Laboratory experiments of the SmartFluo show a linear correlation (R 2 = 0.98) to the chlorophyll a concentrations measured by reference instruments, such as a high-performance benchtop laboratory fluorometer (LS 55, PerkinElmer).

  11. Observations of Cross-Surf-zone / Inner-shelf Dye Exchange from Aerial Hyperspectral and in Situ Data.

    NASA Astrophysics Data System (ADS)

    Grimes, D. J.; Giddings, S. N.; Kumar, N.; Pawlak, G. R.; Feddersen, F.

    2016-12-01

    Understanding the cross-shelf exchange of nearshore sourced tracers across the surfzone and onto the stratified inner-shelf is critical to be able to predict the evolution of pollution events, HAB, and larval transport, which will enable policy and mitigation efforts. The CSIDE (Cross Surfzone / Inner-shelf Dye Exchange) experiment (Sept & Oct 2015) provides observations to quantify dye tracer exchange across the surfzone/inner-shelf region with 3 dye release experiments. Shoreline released dye and temperature is tracked for 48 hrs and 20 km using aerial hyperspectral and IR imagery, in situ near-shoreline fluorometers, moored wire-walkers, AUV, and boat based towed observations. Here, we focus on the 3rd release, where dye was pumped into the mouth of the Tijuana River / Estuary during an ebb tide with low river discharge. The dye field was transported alongshore in a large coherent patch extending 1 km from shore. The plume persisted overnight with weak dilution and its center of mass was observed to move 3+ km north over 18 hrs. Aerial hyperspectral and in situ observations are analyzed to examine the horizontal and vertical dye distribution. In particular, we will explore the extent to which the stratified inner-shelf is a "material barrier," whether an observed surfzone dye and temperature correlation is maintained on the stratified inner-shelf, at what time- and length-scales, and the processes influencing this relationship.

  12. Using fluorescent dissolved organic matter to trace and distinguish the origin of Arctic surface waters

    NASA Astrophysics Data System (ADS)

    Gonçalves-Araujo, Rafael; Granskog, Mats A.; Bracher, Astrid; Azetsu-Scott, Kumiko; Dodd, Paul A.; Stedmon, Colin A.

    2016-09-01

    Climate change affects the Arctic with regards to permafrost thaw, sea-ice melt, alterations to the freshwater budget and increased export of terrestrial material to the Arctic Ocean. The Fram and Davis Straits represent the major gateways connecting the Arctic and Atlantic. Oceanographic surveys were performed in the Fram and Davis Straits, and on the east Greenland Shelf (EGS), in late summer 2012/2013. Meteoric (fmw), sea-ice melt, Atlantic and Pacific water fractions were determined and the fluorescence properties of dissolved organic matter (FDOM) were characterized. In Fram Strait and EGS, a robust correlation between visible wavelength fluorescence and fmw was apparent, suggesting it as a reliable tracer of polar waters. However, a pattern was observed which linked the organic matter characteristics to the origin of polar waters. At depth in Davis Strait, visible wavelength FDOM was correlated to apparent oxygen utilization (AOU) and traced deep-water DOM turnover. In surface waters FDOM characteristics could distinguish between surface waters from eastern (Atlantic + modified polar waters) and western (Canada-basin polar waters) Arctic sectors. The findings highlight the potential of designing in situ multi-channel DOM fluorometers to trace the freshwater origins and decipher water mass mixing dynamics in the region without laborious samples analyses.

  13. Blood ALDH1 and GST activity in diabetes type 2 and its correlation with glycated hemoglobin.

    PubMed

    Giebułtowicz, J; Sołobodowska, S; Bobilewicz, D; Wroczyński, P

    2014-01-01

    There is increasing evidence that oxidative stress (OS) plays a major role in the pathogenesis of diabetes mellitus (DM) and the development of its complications. As one of the consequences of OS is increased lipid peroxidation (LP), the aim of our studies was to check, how the activity of 2 enzymes involved in the detoxification of aldehydes formed during LP, glutathione S-transferase (GST) and aldehyde dehydrogenase 1 (ALDH 1) is changed in patients suffering from DM.GST and ALDH1A1 activities were determined in whole blood samples of DM type 2 patients (n=64) and healthy controls (n=60) using spectrophotometer (for GST activity) and fluorometer (for ALDH1 activity) and they were found to be significantly increased in diabetics when compared with healthy control (p<0.05). Intriguingly, grouping the DM patients on the basis of the glucose level and HbA1c revealed unusually low ALDH activity in the group of patients (n=16) with a relatively high level of these 2 parameters.The increase of ALDH1A1 and GST activity in DM seems to be associated with the severity of the disease and might be a compensatory effect against oxidative stress. Surprisingly low ALDH activity in DM patients with relatively high glucose and HbA1c levels can be a factor predisposing to the development of diabetic complications.

  14. Mid-summer mesozooplankton biomass, its size distribution, and estimated production within a glacial Arctic fjord (Hornsund, Svalbard)

    NASA Astrophysics Data System (ADS)

    Trudnowska, E.; Basedow, S. L.; Blachowiak-Samolyk, K.

    2014-09-01

    The estimation of secondary production constitutes an integrating proxy of pelagic ecosystem status, its functions as well as its responses to environmental stressors. The combination of high-resolution automatic measurements with a Laser Optical Plankton Counter (LOPC) and size spectrum analyses was utilized to estimate the secondary production of a high Arctic fjord during a summer post bloom situation in 2012. The dataset comprised 28 vertical and extensive horizontal hauls of a LOPC-CTD-fluorometer platform plus four zooplankton net sampling stations for taxonomic composition designation. A clear gradient in temperature, salinity, chlorophyll a concentrations as well as mesozooplankton abundance, biomass and production was demonstrated along Hornsund fjord axis. The outer fjord part was under the influence of water advection and had the highest chlorophyll a concentrations, numerous opaque mesozooplankton individuals and flat slopes of size spectra, pointing to long food chains in which biomass is recycled several times. The opposite state was found in the glacial bays, where the glacier meltwater discharge led to low chlorophyll a concentrations but high abundance of small and amorphous particles. It resulted in steep size spectra slopes and high intercepts implying higher potential productivity there. The model of mesozooplankton production demonstrated that Hornsund fjord is a highly productive ecosystem, particularly its upper water layer and its central parts. However, we would like to emphasize that a careful approach is needed before going deeper into ecological interpretations based on size spectra analysis, especially in reservoirs, where non-zooplankton particles contribute to the size spectra.

  15. Development of Loop-Mediated Isothermal Amplification (LAMP) Assay for Rapid and Sensitive Identification of Ostrich Meat

    PubMed Central

    Abdulmawjood, Amir; Grabowski, Nils; Fohler, Svenja; Kittler, Sophie; Nagengast, Helga; Klein, Guenter

    2014-01-01

    Animal species identification is one of the primary duties of official food control. Since ostrich meat is difficult to be differentiated macroscopically from beef, therefore new analytical methods are needed. To enforce labeling regulations for the authentication of ostrich meat, it might be of importance to develop and evaluate a rapid and reliable assay. In the present study, a loop-mediated isothermal amplification (LAMP) assay based on the cytochrome b gene of the mitochondrial DNA of the species Struthio camelus was developed. The LAMP assay was used in combination with a real-time fluorometer. The developed system allowed the detection of 0.01% ostrich meat products. In parallel, a direct swab method without nucleic acid extraction using the HYPLEX LPTV buffer was also evaluated. This rapid processing method allowed detection of ostrich meat without major incubation steps. In summary, the LAMP assay had excellent sensitivity and specificity for detecting ostrich meat and could provide a sampling-to-result identification-time of 15 to 20 minutes. PMID:24963709

  16. Rapid and robust detection methods for poison and microbial contamination.

    PubMed

    Hoehl, Melanie M; Lu, Peter J; Sims, Peter A; Slocum, Alexander H

    2012-06-27

    Real-time on-site monitoring of analytes is currently in high demand for food contamination, water, medicines, and ingestible household products that were never tested appropriately. Here we introduce chemical methods for the rapid quantification of a wide range of chemical and microbial contaminations using a simple instrument. Within the testing procedure, we used a multichannel, multisample, UV-vis spectrophotometer/fluorometer that employs two frequencies of light simultaneously to interrogate the sample. We present new enzyme- and dye-based methods to detect (di)ethylene glycol in consumables above 0.1 wt % without interference and alcohols above 1 ppb. Using DNA intercalating dyes, we can detect a range of pathogens ( E. coli , Salmonella , V. Cholera, and a model for Malaria) in water, foods, and blood without background signal. We achieved universal scaling independent of pathogen size above 10(4) CFU/mL by taking advantage of the simultaneous measurement at multiple wavelengths. We can detect contaminants directly, without separation, purification, concentration, or incubation. Our chemistry is stable to ± 1% for >3 weeks without refrigeration, and measurements require <5 min.

  17. Vertical variation of mixing within porous sediment beds below turbulent flows

    NASA Astrophysics Data System (ADS)

    Chandler, I. D.; Guymer, I.; Pearson, J. M.; van Egmond, R.

    2016-05-01

    River ecosystems are influenced by contaminants in the water column, in the pore water and adsorbed to sediment particles. When exchange across the sediment-water interface (hyporheic exchange) is included in modeling, the mixing coefficient is often assumed to be constant with depth below the interface. Novel fiber-optic fluorometers have been developed and combined with a modified EROSIMESS system to quantify the vertical variation in mixing coefficient with depth below the sediment-water interface. The study considered a range of particle diameters and bed shear velocities, with the permeability Péclet number, PeK between 1000 and 77,000 and the shear Reynolds number, Re*, between 5 and 600. Different parameterization of both an interface exchange coefficient and a spatially variable in-sediment mixing coefficient are explored. The variation of in-sediment mixing is described by an exponential function applicable over the full range of parameter combinations tested. The empirical relationship enables estimates of the depth to which concentrations of pollutants will penetrate into the bed sediment, allowing the region where exchange will occur faster than molecular diffusion to be determined.

  18. InSitu-Eye: oceanological and atmospheric data processing and analyzing system

    NASA Astrophysics Data System (ADS)

    Stepochkin, Igor E.; Salyuk, Pavel A.; Shmirko, Konstantin A.; Golik, Irina A.; Burov, Denis V.

    2014-11-01

    In this study we introduce brief description and the main approaches used in system development. System is devising with a participation of Pacific Oceanological Institute (FEB RAS), Institute of Automation and Control Processes (FEB RAS) and also Maritime State University, n.a. G.I. Nevelskoy. For many years research team of these institutions carried out a lot of field measurements and collected a lot of remote sensing data, using spectrophotometers, LIDARs, fluorometers. The primary goal of this development - bring all this data together to integrated database and design user-friendly interface to work with. "InSitu-Eye" will perform standard routine operations, such as sampling data according to certain parameters; gridding and timing of data; filtering and quality check of data; visualization. After setting system up and testing it will provide a benefit. At first it gives 24/7 access to "clean", checked "in-situ" data, ready for further research. Also presence of such system gives "converse effect" - it will become necessary to develop strict protocols for measurements carrying out and increase their quality. In future, "InSitu-Eye" can become a platform, connecting research teams for data keeping and exchange.

  19. Simultaneous three-dimensional velocity and mixing measurements by use of laser Doppler velocimetry and fluorescence probes in a water tunnel

    NASA Technical Reports Server (NTRS)

    Neuhart, Dan H.; Wing, David J.; Henderson, Uleses C., Jr.

    1994-01-01

    A water tunnel investigation was conducted to demonstrate the capabilities of a laser-based instrument that can measure velocity and fluorescence intensity simultaneously. Fluorescence intensity of an excited fluorescent dye is directly related to concentration level and is used to indicate the extent of mixing in flow. This instrument is a three-dimensional laser Doppler velocimeter (LDV) in combination with a fluorometer for measuring fluorescence intensity variations. This capability allows simultaneous flow measurements of the three orthogonal velocity components and mixing within the same region. Two different flows which were generated by two models were studied: a generic nonaxisymmetric nozzle propulsion simulation model with an auxiliary internal water source that generated a jet flow and an axisymmetric forebody model with a circular sector strake that generated a vortex flow. The off-body flow fields around these models were investigated in the Langley 16- by 24-Inch Water Tunnel. The experimental results were used to calculate 17 quantities that included mean and fluctuating velocities, Reynolds stresses, mean and fluctuating dye fluorescence intensities (proportional to concentration), and fluctuating velocity and dye concentration correlations. An uncertainty analysis was performed to establish confidence levels in the experimental results. In general, uncertainties in mean velocities varied between 1 and 7 percent of free-stream velocity; uncertainties in fluctuating velocities varied between 1 and 5 percent of reference values. The results show characteristics that are unique to each type of flow.

  20. Deleterious effects of swimming pool chlorine on the corneal epithelium.

    PubMed

    Ishioka, Misaki; Kato, Naoko; Kobayashi, Akira; Dogru, Murat; Tsubota, Kazuo

    2008-01-01

    To study the effect of rinsing with tap and pool water on the ocular surface epithelium. Twenty eyes of 10 volunteers were irrigated in the following order with 250 mL (50 seconds) of physiological salt solution (PSS), distilled water (DW), tap water, or PSS with chlorine (0.5 mg/L). The pH of each fluid was 6.4, 6.8, 6.8, and 6.4, respectively. Vital staining, fluorophotometric assessment, and confocal microscopy were performed before and after irrigation with each fluid. Eyes irrigated with PSS with chlorine showed an increase in fluorescein scores, and eyes washed with both tap water and PSS with chlorine showed an increase in Rose Bengal scores. Corneal fluorescein uptake measured by anterior fluorometer was not altered by eye irrigation with PSS, DW, or tap water. However, PSS with chlorine resulted in a significant increase in corneal fluorescein uptake. Confocal microscopy showed corneal epithelial cell damage in eyes rinsed with PSS with chlorine. Chlorine was determined to be potentially harmful to the corneal epithelial barrier. This study indicated the possibility that swimming without goggles might become a risk factor for corneal epithelial integrity, suggesting encouragement of goggle wear while swimming.

  1. New technological developments for ocean LIDAR biomonitoring

    NASA Astrophysics Data System (ADS)

    Chekalyuk, Alexander M.; Hoge, Frank E.; Swift, Robert N.; Yungel, James K.

    2003-11-01

    A pump-and-probe (P&P) airborne LIDAR has been recently developed at NASA Goddard Space Flight Center. It provides remote measurement of phytoplankton photosynthetic variables along with pigment and organic matter fluorescence, down-welling and upwelling hyperspectral measurements and sea surface temperature. The utilization of an airborne platform provides for rapid remote characterization of phytoplankton photosynthetic activity, biomass and diversity over large aquatic areas. The P&P LIDAR technique is one of the first practical implementations of 'superactive' remote sensing. This presentation summarizes results of six airborne measurement campaigns conducted in 1999-2002 in the Chesapeake Bay, Delaware Bay, Middle Atlantic Bight, and Gulf of Mexico. The P&P technology has been complemented by a Laser Phytoplankton Analyzer (LPA), a shipboard laser fluorometer dedicated to technological advancement in pigment analysis that will be implemented in future LIDAR systems. It combines high-resolution spectral measurements of phytoplankton pigment fluorescence excited at several selected wavelengths with active assessment of the physiological status of the phytoplankton photosynthetic apparatus. Emission/excitation measurements provide a potential for assessing concentrations of photosynthetic accessory pigments (Chlorophyll a, b, c, photosynthetic carotenoids and phycobilins) and identifying major phytoplankton functional groups. The LPA was extensively tested in laboratory experiments with phytoplankton cultures and their mixtures. In November 2002, the LPA was utilized for pigment fluorescence analysis of natural phytoplankton over a range if environmental conditions on a research cruise in the Middle Atlantic Bight and Delaware Bay.

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

    PubMed

    Taniguchi, Midori; Saito, Hirokazu; Mitsubayashi, Kohji

    2017-09-19

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

  3. Vertical variation of mixing within porous sediment beds below turbulent flows

    PubMed Central

    Chandler, I. D.; Pearson, J. M.; van Egmond, R.

    2016-01-01

    Abstract River ecosystems are influenced by contaminants in the water column, in the pore water and adsorbed to sediment particles. When exchange across the sediment‐water interface (hyporheic exchange) is included in modeling, the mixing coefficient is often assumed to be constant with depth below the interface. Novel fiber‐optic fluorometers have been developed and combined with a modified EROSIMESS system to quantify the vertical variation in mixing coefficient with depth below the sediment‐water interface. The study considered a range of particle diameters and bed shear velocities, with the permeability Péclet number, PeK between 1000 and 77,000 and the shear Reynolds number, Re*, between 5 and 600. Different parameterization of both an interface exchange coefficient and a spatially variable in‐sediment mixing coefficient are explored. The variation of in‐sediment mixing is described by an exponential function applicable over the full range of parameter combinations tested. The empirical relationship enables estimates of the depth to which concentrations of pollutants will penetrate into the bed sediment, allowing the region where exchange will occur faster than molecular diffusion to be determined. PMID:27635104

  4. Laboratory testing protocol for the impact of dispersed petrochemicals on seagrass.

    PubMed

    Wilson, K G; Ralph, P J

    2012-11-01

    To improve the effectiveness of oil spill mitigation, we developed a rapid, logistically simple protocol to detect petrochemical stress on seagrass. Sections of leaf blades from Zostera muelleri subsp. capricorni were exposed to the water accommodated fraction (WAF) of non-dispersed and dispersed Tapis crude oil and fuel oil (IFO-380) for 5h. Photosynthetic health was monitored by assessing changes in effective quantum yield of photosystem II (ΔF/F(m)(')) and chlorophyll a pigment concentrations. Loss of total petroleum hydrocarbons (TPH) was measured using an oil-in-water fluorometer, whilst GC-MS analyses quantified the hydrocarbon components within each treatment. Few significant differences were detected in the chlorophyll a pigment analyses; however, ΔF/F(m)(') appeared sensitive to petrochemical exposure. Dispersing both types of oil resulted in a substantial increase in the TPH of the WAF and was generally correlated with a greater physiological impact to the seagrass health, compared with the oil alone. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. The influence of PAH concentration and distribution on real-time in situ measurements of petroleum products in soils using laser induced fluorescence

    SciTech Connect

    Douglas, G.S.; Lieberman, S.H.; McGinnis, W.C.; Knowles, D.; Peven, C.

    1995-12-31

    Real-time laser induced fluorescence (LIF) in situ measurements of soil samples provide a reliable and cost-effective screening tool for hydrocarbon site assessments. The site characterization and analysis penetrometer system (SCAPS), is a truck-mounted cone penetrometer probe modified with a sapphire window and connected to a laser by fiber optics. The pulsed nitrogen laser 337-nm excitation source induces fluorescence in polynuclear aromatic hydrocarbons (PAHs), which are present in petroleum products. The fluorescence response of these compounds is measured with a fluorometer. The SCAPS can provide continuous hydrocarbon screening measurements to soil depths greater than 100 feet. Discrete soil samples collected from the SCAPS boreholes were extracted and analyzed for total petroleum hydrocarbons (TPH), by gas chromatography with flame ionization detection (GC/FID), and 16 parent and over 100 alkyl substituted PAH compounds by gas chromatography with mass spectrometry detection (GC/MS). This method provides a basis for evaluating the relationship between TPH and PAH concentrations in the soil samples and laser induced fluorescence measurements from the soil borings.

  6. In vitro evaluation of the capacity of zeolite and bentonite to adsorb aflatoxin B1 in simulated gastrointestinal fluids.

    PubMed

    Thieu, N Q; Pettersson, H

    2008-09-01

    Anin vitro study using single concentration and isotherm adsorption was carried out to evaluate the capacity of Vietnamese produced zeolite and bentonite to adsorb aflatoxin B1 (AFB1) in simulated gastrointestinal fluids (SGFs), and a commercial sorbent hydrated sodium calcium aluminosilicate (HSCAS) was used as reference. In this study, AFB1 solution was mixed with sorbents (0.3, 0.4 and 0.5% w/v) in SGFs at pH 3 and pH 7 and shaken for 8 h, centrifuged and the supernatant measured by Vicam fluorometer. Adsorption of AFB1 onto zeolite and bentonite varied according to the pH of SGFs and was lower than HSCAS. Linearity between the increased amount of AFB1 adsorbed on sorbents and the decrease of sorbent concentration was observed for bentonite and HSCAS, except for zeolite in SGFs at pH 7. The observed maximum amounts of AFB1 adsorbed on bentonite and HSCAS were 1.54 and 1.56 mg/g, respectively. The adsorption capacities of bentonite and HSCAS for AFB1 were 12.7 and 13.1 mg/g, respectively, from fitting the data to the Freundlich isotherm equation. Improvement in processing and purification for bentonite is needed to enhance the surface area, which would probably result in better adsorptive capacity for this sorbent.

  7. Non-Instrumented Nucleic Acid Amplification (NINA) for Rapid Detection of Ralstonia solanacearum Race 3 Biovar 2

    PubMed Central

    Kubota, Ryo; LaBarre, Paul; Singleton, Jered; Beddoe, Andy; Weigl, Bernhard H.; Alvarez, Anne M.; Jenkins, Daniel M.

    2014-01-01

    We report on the use of a non-instrumented device for the implementation of a loop-mediated amplification (LAMP) based assay for the select-agent bacterial-wilt pathogen Ralstonia solanacearum race 3 biovar 2. Heat energy is generated within the device by the exothermic hydration of calcium oxide, and the reaction temperature is regulated by storing latent energy at the melting temperature of a renewable lipid-based engineered phase-change material. Endpoint detection of the LAMP reaction is achieved without opening the reaction tube by observing the fluorescence of an innovative FRET-based hybridization probe with a simple custom fluorometer. Non-instrumented devices could maintain reactions near the design temperature of 63°C for at least an hour. Using this approach DNA extracted from the pathogen could be detected at fewer than ten copies within a 25 μL reaction mix, illustrating the potential of these technologies for simple, powerful agricultural diagnostics in the field. Furthermore, the assay was just as reliable when implemented in a tropical environment at 31°C as it was when implemented in an air-conditioned lab maintained at 22°C, illustrating the potential value of the technology for field conditions in the tropics and subtropics. PMID:25485176

  8. In-Field Implementation of a Recombinant Factor C Assay for the Detection of Lipopolysaccharide as a Biomarker of Extant Life within Glacial Environments.

    PubMed

    Barnett, Megan J; Wadham, Jemma L; Jackson, Miriam; Cullen, David C

    2012-03-09

    The discovery over the past two decades of viable microbial communities within glaciers has promoted interest in the role of glaciers and ice sheets (the cryosphere) as contributors to subglacial erosion, global biodiversity, and in regulating global biogeochemical cycles. In situ or in-field detection and characterisation of microbial communities is becoming recognised as an important approach to improve our understanding of such communities. Within this context we demonstrate, for the first time, the ability to detect Gram-negative bacteria in glacial field-environments (including subglacial environments) via the detection of lipopolysaccharide (LPS); an important component of Gram-negative bacterial cell walls. In-field measurements were performed using the recently commercialised PyroGene® recombinant Factor C (rFC) endotoxin detection system and used in conjunction with a handheld fluorometer to measure the fluorescent endpoint of the assay. Twenty-seven glacial samples were collected from the surface, bed and terminus of a low-biomass Arctic valley glacier (Engabreen, Northern Norway), and were analysed in a field laboratory using the rFC assay. Sixteen of these samples returned positive LPS detection. This work demonstrates that LPS detection via rFC assay is a viable in-field method and is expected to be a useful proxy for microbial cell concentrations in low biomass environments.

  9. Use of multiple sensor technologies for quality control of in situ biogeochemical measurements: A SeaCycler case study

    NASA Astrophysics Data System (ADS)

    Atamanchuk, Dariia; Koelling, Jannes; Lai, Jeremy; Send, Uwe; Wallace, Douglas

    2017-04-01

    Over the last two decades observing capacity for the global ocean has increased dramatically. Emerging sensor technologies for dissolved gases, nutrients and bio-optical properties in seawater are allowing extension of in situ observations beyond the traditionally measured salinity, temperature and pressure (CTD). However the effort to extend observations using autonomous instruments and platforms carries the risk of losing the level of data quality achievable through conventional water sampling techniques. We will present results from a case study with the SeaCycler profiling winch focusing on quality control of the in-situ measurements. A total of 13 sensors were deployed from May 2016 to early 2017 on SeaCycler's profiling sensor float, including CTD, dissolved oxygen (O2, 3 sensors), carbon dioxide (pCO2, 2 sensors), nutrients, velocity sensors, fluorometer, transmissometer, single channel PAR sensor, and others. We will highlight how multiple measurement technologies (e.g. for O2 and CO2) complement each other and result in a high quality data product. We will also present an initial assessment of the bio-optical data, their implications for seasonal phytoplankton dynamics and comparisons to climatologies and ocean-color data products obtained from the MODIS satellite.

  10. One-step solid-phase extraction cleanup and fluorometric analysis of deoxynivalenol in grains.

    PubMed

    Malone, B R; Humphrey, C W; Romer, T R; Richard, J L

    1998-01-01

    A rapid, quantitative, inexpensive, efficient method was developed to determine deoxynivalenol (DON) in wheat, barley, corn, wheat middlings, wheat flour, bran, malted barley, and oats. Samples are ground and extracted with acetonitrile-water (86 + 14). A portion of the extract is cleaned up by passage through a MycoSep No. 225 column, evaporated to dryness, and derivatized with zirconyl nitrate and ethylenediamine in methanol. The resulting fluorescent derivative of DON is identified and quantitated with a calibrated fluorometer containing a broad wavelength pulsed xenon light source. This method quantitated DON concentrations from 0.5 to 50 ppm without dilution and was linear when applied to samples of noncontaminated wheat spiked at 0.5, 5, 10, 25, and 50 micrograms DON/g. Correlation coefficients of the method with LC for multiple analyses (n > or = 14 for each commodity) applied to wheat, corn, barley, wheat flour, and wheat middlings were 0.99, 0.99, 0.99, 0.93, and 0.98, respectively. Individual analyses were conducted in < 30 min, and 24 samples were analyzed in 2 h.

  11. Remote monitoring of chlorophyll fluorescence in two reef corals during the 2005 bleaching event at Lee Stocking Island, Bahamas

    NASA Astrophysics Data System (ADS)

    Manzello, D.; Warner, M.; Stabenau, E.; Hendee, J.; Lesser, M.; Jankulak, M.

    2009-03-01

    Zooxanthellae fluorescence was measured in situ, remotely, and in near real-time with a pulse amplitude modulated (PAM) fluorometer for a colony of Siderastrea siderea and Agaricia tenuifolia at Lee Stocking Island, Bahamas during the Caribbean-wide 2005 bleaching event. These colonies displayed evidence of photosystem II (PS II) inactivation coincident with thermal stress and seasonally high doses of solar radiation. Hurricane-associated declines in temperature and light appear to have facilitated the recovery of maximum quantum yield of PS II within these two colonies, although both corals responded differently to individual storms. PAM fluorometry, coupled with long-term measurement of in situ light and temperature, provides much more detail of coral photobiology on a seasonal time scale and during possible bleaching conditions than sporadic, subjective, and qualitative observations. S. siderea displayed evidence of PS II inactivation over a month prior to the issuing of a satellite-based, sea surface temperature (SST) bleaching alert by the National Oceanic and Atmospheric Administration (NOAA). In fact, recovery had already begun in S. siderea when the bleaching alert was issued. Fluorescence data for A. tenuifolia were difficult to interpret because the shaded parts of a colony were monitored and thus did not perfectly coincide with thermal stress and seasonally high doses of solar radiation as in S. siderea. These results further emphasize the limitations of solely monitoring SST (satellite or in situ) as a bleaching indicator without considering the physiological status of coral-zooxanthellae symbioses.

  12. Photosynthesis assessment in microphytobenthos using conventional and imaging pulse amplitude modulation fluorometry.

    PubMed

    Vieira, Sónia; Ribeiro, Lourenço; Jesus, Bruno; Cartaxana, Paulo; da Silva, Jorge Marques

    2013-01-01

    Imaging pulse amplitude modulated (Imaging-PAM) fluorometry is a breakthrough in the study of spatial heterogeneity of photosynthetic assemblages. However, Imaging and conventional PAM uses a different technology, making comparisons between these techniques doubtful. Thereby, photosynthetic processes were comparatively assessed using conventional (Junior PAM and PAM 101) and Imaging-PAM on intertidal microphytobenthos (MPB; mud and sand) and on cork oak leaves. Lower values of α (initial slope of the rETR, relative photosynthetic electron transport rate) vs E (incident photosynthetic active radiation) curve), ETR(max) (maximum relative ETR), E(k) (light saturation parameter) and F(v)/F(m) (maximum quantum efficiency of photosystem II of dark-adapted samples) were obtained using the Imaging-PAM. The level of discrepancy between conventional and Imaging-PAM systems was dependent on the type of sample, being more pronounced for MPB muddy sediments. This may be explained by differences in the depth integration of the fluorescence signal related to the thickness of the photosynthetic layer and in the light attenuation coefficients of downwelling irradiance. An additional relevant parameter is the taxonomic composition of the MPB, as cyanobacteria present in sandy sediments rendered different results with red and blue excitation light fluorometers. These findings emphasize the caution needed when interpreting chlorophyll fluorescence data of MPB communities. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  13. In-Field Implementation of a Recombinant Factor C Assay for the Detection of Lipopolysaccharide as a Biomarker of Extant Life within Glacial Environments

    PubMed Central

    Barnett, Megan J.; Wadham, Jemma L.; Jackson, Miriam; Cullen, David C.

    2012-01-01

    The discovery over the past two decades of viable microbial communities within glaciers has promoted interest in the role of glaciers and ice sheets (the cryosphere) as contributors to subglacial erosion, global biodiversity, and in regulating global biogeochemical cycles. In situ or in-field detection and characterisation of microbial communities is becoming recognised as an important approach to improve our understanding of such communities. Within this context we demonstrate, for the first time, the ability to detect Gram-negative bacteria in glacial field-environments (including subglacial environments) via the detection of lipopolysaccharide (LPS); an important component of Gram-negative bacterial cell walls. In-field measurements were performed using the recently commercialised PyroGene® recombinant Factor C (rFC) endotoxin detection system and used in conjunction with a handheld fluorometer to measure the fluorescent endpoint of the assay. Twenty-seven glacial samples were collected from the surface, bed and terminus of a low-biomass Arctic valley glacier (Engabreen, Northern Norway), and were analysed in a field laboratory using the rFC assay. Sixteen of these samples returned positive LPS detection. This work demonstrates that LPS detection via rFC assay is a viable in-field method and is expected to be a useful proxy for microbial cell concentrations in low biomass environments. PMID:25585634

  14. Biovolume spectrum theories applied: spatial patterns of trophic levels within a mesozooplankton community at the polar front.

    PubMed

    Basedow, Sünnje L; Tande, Kurt S; Zhou, Meng

    2010-08-01

    Three-dimensional data on the mesoscale distribution of hydrography and mesozooplankton were collected at the Polar Front, northwestern Barents Sea, in spring 2008 (29 April-15 May) using a combination of multinet and towed instrument platform equipped with Laser Optical Plankton Counter, fluorometer and CTD. Trophic levels (TLs) within the zooplankton community (whole community and size-separated) were analysed for three consecutive periods using biovolume spectrum theory, which proved to be a powerful tool in the physically and biologically variable frontal system. Trophic structure was highly variable in time and across the Polar Front, but was mostly related to the phytoplankton bloom (as determined by fluorescence). High TLs of 5.5 within the zooplankton community were observed outside bloom situations (mostly in Atlantic Water) and were likely due to increased omnivory of Calanus spp., which dominated the large zooplankton size group that had a lower TL (2.2) during the bloom than outside blooms (max. TL 5.6). A strong input of herbivorous barnacle nauplii (Cirripedia) into the upper layer (35 000 ind. m(-3) in net samples) substantially decreased mean TL in the marginal ice zone. Differences in TL estimates based on biovolume spectrum theory and other methods (stable isotopes, lipid markers, dietary analyses) are discussed.

  15. Mesoscale variation in the photophysiology of the reef building coral Pocillopora damicornis along an environmental gradient

    NASA Astrophysics Data System (ADS)

    Cooper, Timothy F.; Ulstrup, Karin E.

    2009-06-01

    Spatial variation in the photophysiology of symbiotic dinoflagellates (zooxanthellae) of the scleractinian coral Pocillopora damicornis was examined along an environmental gradient in the Whitsunday Islands (Great Barrier Reef) at two depths (3 m and 6 m). Chlorophyll a fluorescence of photosystem II (PSII) and PAR-absorptivity measurements were conducted using an Imaging-PAM (pulse-amplitude-modulation) fluorometer. Most photophysiological parameters correlated with changes in environmental conditions quantified by differences in water quality along the gradient. For example, maximum quantum yield ( Fv/ Fm) increased and PAR-absorptivity decreased as water quality improved along the gradient from nearshore reefs (low irradiance, elevated nutrients and sediments) to outer islands (high irradiance, low nutrients and sediments). For apparent photosynthetic rate (PS max) and minimum saturating irradiance ( Ek), the direction of change differed depending on sampling depth, suggesting that different mechanisms of photo-acclimatisation operated between shallow and deep corals. Deep corals conformed to typical patterns of light/shade acclimatisation whereas shallow corals exhibited reduced PS max and Ek with improving water quality coinciding with greater heat dissipation (NPQ 241). Furthermore, deep corals on nearshore reefs exhibited elevated Q241 in comparison to outer islands possibly due to effects of sedimentation and/or pollutants rather than irradiance. These results highlight the importance of mesoscale sampling to obtain useful estimates of the variability of photophysiological parameters, particularly if such measures are to be used as bioindicators of the condition of coral reefs.

  16. Photosynthetic responses of thalli and isolated protoplasts of Bryopsis hypnoides (Bryopsidales, Chlorophyta) during dehydration

    NASA Astrophysics Data System (ADS)

    Lü, Fang; Wang, Guangce; Jin, Haochen

    2011-03-01

    Bryopsis hypnoides Lamouroux is a unique intertidal siphonous green alga whose extruded protoplasm can aggregate spontaneously in seawater to form numerous new cells that can develop into mature algal thalli. In this study, the photosynthetic responses during dehydration of both the thalli and protoplasts isolated from B. hypnoides were measured using a Dual-PAM (pulse amplitude modulation)-100 fluorometer. The results show that the photosynthetic rates of B. hypnoides thalli were maintained for an initial period, beyond which continued desiccation resulted in reduced rates of PSI and PSII. However, the photosynthetic performances of the isolated protoplasts dehydrated in air (CO2 concentration 600-700 mg/L) showed a slight increase of Y(II) at 20% water loss, but the rates decreased thereafter with declining water content. When protoplasts were dehydrated in CO2 deficient conditions (CO2 concentration 40-80 mg/L), the values of Y(II) declined steadily with increased dehydration without an initial rise. These results indicated that the thalli and isolated protoplasts of this alga can utilize CO2 in ambient air effectively, and the photosynthetic performances of the isolated protoplasts were significantly different from that of the thalli during dehydration. Thus the protoplasts may be an excellent system for the study of stress tolerance.

  17. Liquid-chromatographic separation and on-line bioluminescence detection of creatine kinase isoenzymes

    SciTech Connect

    Bostick, W.D.; Denton, M.S.; Dinsmore, S.R.

    1980-01-01

    Isoenzymes of creatine kinase were separated by anion-exchange chromatography, with use of an elution gradient containing lithium acetate (0.1 to 0.6 mol/L). A stream splitter was used to divert a 5% side stream of column effluent, which was subsequently mixed with the reagents necessary for bioluminescence assay of the separated isoenzymes. The use of the stream splitter greatly decreased the rate of consumption of reagent and, when combined with a peristaltic pumping system, permitted independent control of the side-stream flow rate. Thus both the residence interval in a delay coil in which the ATP reaction product is formed and the bioluminescence emission was monitored in a flow-through fluorometer without use of an external light source or filters. Separation and detection of the isoenzymes of creatine kinase were rapid, sensitive, and highly selective. The incremental decrease of bioluminescence response owing to inhibition by the ions in the eluent was less than 31% across the entire gradient.

  18. Variation among Species in the Temperature Dependence of the Reappearance of Variable Fluorescence following Illumination.

    PubMed

    Burke, J J

    1990-06-01

    The relationship between the thermal dependence of the reappearance of chlorophyll variable fluorescence following illumination and temperature dependence of the apparent Michaelis constant (K(m)) of NADH hydroxypyruvate reductase for NADH was investigated in cool and warm season plant species. Brancker SF-20 and SF-30 fluorometers were used to evaluate induced fluorescence transients from detached leaves of wheat (Triticum aestivum L. cv TAM-101), cotton (Gossypium hirsutum L. cv Paymaster 145), tomato (Lycopersicon esculentum cv Del Oro), bell pepper (Capsicum annuum L. cv California Wonder), and petunia (Petunia hybrida cv. Red Sail). Following an illumination period at 25 degrees C, the reappearance of variable fluorescence during a dark incubation was determined at 5 degrees C intervals from 15 degrees C to 45 degrees C. Variable fluorescence recovery was normally distributed with the maximum recovery observed at 20 degrees C in wheat, 30 degrees C in cotton, 20 degrees C to 25 degrees C in tomato, 30 to 35 degrees C in bell pepper and 25 degrees C in petunia. Comparison of the thermal response of fluorescence recovery with the temperature sensitivity of the apparent K(m) of hydroxypyruvate reductase for NADH showed that the range of temperatures providing fluorescence recovery corresponded with those temperatures providing the minimum apparent K(m) values (viz. the thermal kinetic window).

  19. A model considering light reabsorption processes to correct in vivo chlorophyll fluorescence spectra in apples.

    PubMed

    Ramos, María E; Lagorio, María G

    2006-05-01

    Chlorophyll-a contained in the peel of Granny Smith apples emits fluorescence upon excitation with blue light. The observed emission, collected by an external detector and corrected by its spectral response, is still distorted by light reabsorption processes taking place in the fruit skin and differs appreciably from the true spectral distribution of fluorescence emerging from chlorophyll molecules in the biological tissue. Reabsorption processes particularly affect the ratio of fluorescence intensities at 680 nm and at 730 nm. A model to obtain the correct spectral distribution of the emission, from the experimental fluorescence recorded at a fluorometer detector and corrected for the detector spectral sensitivity, is developed in the present work. Measurements of the whole fruit reflectance, the peel transmittance and the flesh reflectance allow the calculation of the reabsorption-corrected spectra. The model is validated by comparing the corrected emission spectra with that obtained for a thin layer of apple-peel-chloroplasts, where no reabsorption takes place. It is recommended to correct distortions in emission spectra of intact fruits due to light reabsorption effects whenever a correlation between the physiological state of the fruit and its fluorescence spectra is investigated.

  20. Structural and nonlinear optical characterizations of ZnS/ PVP nanocomposites synthesized by pulsed laser ablation

    NASA Astrophysics Data System (ADS)

    Divyasree, M. C.; Chandrasekharan, K.

    2017-05-01

    ZnS/Poly Vinyl Pyrrolidone nanocomposites were synthesized by pulsed laser ablation at ambient conditions using an Nd: YAG laser at 532 nm wavelength and 7ns pulse width. Linear optical characterizations were done using UV-Vis spectrophotometer and fluorometer. Both absorption and emission peaks were found to be blue shifted, which could be due to quantum confinement effect. Spherical morphology and the purity in the elemental composition of the sample were confirmed by scanning electron microscope and energy dispersive X-ray spectrometer respectively. Average particle size of the ZnS nanoparticles was found to be 13.45 nm from the Gaussian fitted histogram of transmission electron Microscopy image and the structure was confirmed as hexagonal wurtzite by X-ray diffraction analysis. The nonlinear optical parameters were figured out by z scan analysis with the same laser system. The nanocomposite showed good absorptive and refractive properties in the nonlinear optical regime. Detailed study of the nanocomposite revealed its potential applications in optoelectronics and nonlinear optical device fabrication.

  1. [Cloning of 5', 3' flanking sequence of ovine BLG and regulating the expression of GFP in mammary gland cell line].

    PubMed

    Liu, Ming-Jun; Li, Wen-Rong; Wu, Jian; Huang, Jun-Cheng; Guo, Zhi-Qin; Qu, Xin-Yong; Paul, Kroon

    2002-01-01

    5' and 3' flanking region of ovine BLG were amplified from sheep genomic DNA according to the published whole sequence of ovine BLG and cloned to pGEM-T vector correspondently. By partially sequencing, the sequences of BLG 5' and 3' flanking were the same as that of publication completely. The recombinant structure used to direct exogenous gene especially to express in mammary gland was constructed by joining 4.2 kb 5' flanking with 2.1 kb 3' flanking. In order to assess the efficiency of BLG regulatory elements, green fluorescent protein (GFP) gene as a reporter was fused with BLG construct and transfected the mammary epithelial cells (TD47). Through observation under UV microscope and detection by fluorometer, it is demonstrated that the GFP has been successfully expressed in TD47 cell line. By virtue of direct observation and quantitative analysis, the BLG-GFP construct can be served as a model for the quick assessment of mammary gland expression construct.

  2. Photodynamic therapy in the cattle protozoan Tritrichomonas foetus cultivated on superhydrophilic carbon nanotube.

    PubMed

    Machado, Susane Moreira; Pacheco-Soares, Cristina; Marciano, Fernanda Roberta; Lobo, Anderson Oliveira; da Silva, Newton Soares

    2014-03-01

    Superhydrophilic vertically aligned carbon nanotubes (VACNT-O2) were used for the first time as scaffolds for photodynamic therapy (PDT) to induce inhibition of cell division in eukaryotic cells. VACNT-O2 scaffolds were produced on Ti substrates using plasma enhanced chemical vapor deposition technique and functionalized by oxygen plasma. Scanning electron microscopy (SEM) analysis was performed to characterize the surface changes of the protozoan and interaction with VACNT-O2. Characterization of lipid and total protein expression was performed with protozoa that were or not treated with PDT. Quantification of protein was conducted using Qubit fluorometer and separated on a polyacrylamide gel. SEM analysis showed the release of lipid vesicles by protozoa after the PDT. These vesicles were characterized by the PKH26 fluorescent probe. The results demonstrated a greater amount of protein released after PDT than in the control. When analyzing the protein material in polyacrylamide gel, a significant protein expression of approximately 65 kDa was found. A model identified the programmed death of Tritrichomonas foetus after the PDT was also proposed.

  3. Using fluorescent dissolved organic matter to trace and distinguish the origin of Arctic surface waters

    PubMed Central

    Gonçalves-Araujo, Rafael; Granskog, Mats A.; Bracher, Astrid; Azetsu-Scott, Kumiko; Dodd, Paul A.; Stedmon, Colin A.

    2016-01-01

    Climate change affects the Arctic with regards to permafrost thaw, sea-ice melt, alterations to the freshwater budget and increased export of terrestrial material to the Arctic Ocean. The Fram and Davis Straits represent the major gateways connecting the Arctic and Atlantic. Oceanographic surveys were performed in the Fram and Davis Straits, and on the east Greenland Shelf (EGS), in late summer 2012/2013. Meteoric (fmw), sea-ice melt, Atlantic and Pacific water fractions were determined and the fluorescence properties of dissolved organic matter (FDOM) were characterized. In Fram Strait and EGS, a robust correlation between visible wavelength fluorescence and fmw was apparent, suggesting it as a reliable tracer of polar waters. However, a pattern was observed which linked the organic matter characteristics to the origin of polar waters. At depth in Davis Strait, visible wavelength FDOM was correlated to apparent oxygen utilization (AOU) and traced deep-water DOM turnover. In surface waters FDOM characteristics could distinguish between surface waters from eastern (Atlantic + modified polar waters) and western (Canada-basin polar waters) Arctic sectors. The findings highlight the potential of designing in situ multi-channel DOM fluorometers to trace the freshwater origins and decipher water mass mixing dynamics in the region without laborious samples analyses. PMID:27667721

  4. Biological membrane modeling with a liquid/liquid interface. Probing mobility and environment with total internal reflection excited fluorescence.

    PubMed Central

    Morrison, L E; Weber, G

    1987-01-01

    Total internal reflection of exciting light, in combination with fluorescence intensity and polarization measurements, was used to selectively study fluorescent compounds adsorbed to the interface region between two immiscible liquids. A fluorometer was constructed which provided excitation at variable angles of incidence and allowed sensitive detection of polarized fluorescence emitted from the interface. The compound 4,4'-bis-1-phenylamino-8-naphthalenesulfonate (bis-ANS) was examined at a decalin/water interface and was found to possess remarkable affinity for the interface region with the bulk of the adsorbed molecule residing in the decalin phase. The adsorbed fluorophore displayed an apparent hindered rotation in the plane of the interface with a rotational diffusion coefficient 3- to 12-fold lower than that expected for bis-ANS in solution. While other dyes examined were not found to be significantly surface active, the addition of cationic surfactant sufficed to induce adsorption of the anionic fluorophore 1-aminonaphthalene-3,6,8-trisulfonic acid. This fluoropore was found to reside in an aqueous environment when bound to the interface, and it also exhibited hindered rotation in the plane of the interface. As the concentrations of the dyes were increased, both adsorbed dyes exhibited polarization reductions consistent with excitation energy transfer. Adsorption of bis-ANS was reversed by addition of bovine serum albumin. The membrane protein cytochrome b5 was found not to bind at the decalin/water interface, indicating that interaction with lipid is required for its adherence to biological membranes. PMID:3651556

  5. Fluorescence lifetime measurements of native and glycated human serum albumin and bovine serum albumin

    NASA Astrophysics Data System (ADS)

    Joshi, Narahari V.; Joshi, Virgina O. d.; Contreras, Silvia; Gil, Herminia; Medina, Honorio; Siemiarczuk, Aleksander

    1999-05-01

    Nonenzymatic glycation, also known as Maillard reaction, plays an important role in the secondary complications of the diabetic pathology and aging, therefore, human serum albumin (HSA) and bovine serum albumin (BSA) were glycated by a conventional method in our laboratory using glucose as the glycating agent. Fluorescence lifetime measurements were carried out with a laser strobe fluorometer equipped with a nitrogen/dye laser and a frequency doubler as a pulsed excitation source. The samples were excited at 295 nm and the emission spectra were recorded at 345 nm. The obtained decay curves were tried for double and triple exponential functions. It has been found that the shorter lifetime increases for glycated proteins as compared with that of the native ones. For example, in the case of glycated BSA the lifetime increased from 1.36 ns to 2.30 ns. Similarly, for HSA, the lifetime increases from 1.58 ns to 2.26 ns. Meanwhile, the longer lifetime changed very slightly for both proteins (from 6.52 ns to 6.72 ns). The increase in the lifetime can be associated with the environmental effect; originated from the attachment of glucose to some lysine residues. A good example is Trp 214 which is in the cage of Lys 225, Lys 212, Lys 233, Lys 205, Lys 500, Lys 199 and Lys 195. If fluorescence lifetime technique is calibrated and properly used it could be employed for assessing glycation of proteins.

  6. Self-adjustment of stream bed roughness and flow velocity in a steep mountain channel

    NASA Astrophysics Data System (ADS)

    Schneider, Johannes M.; Rickenmann, Dieter; Turowski, Jens M.; Kirchner, James W.

    2015-10-01

    Understanding how channel bed morphology affects flow conditions (and vice versa) is important for a wide range of fluvial processes and practical applications. We investigated interactions between bed roughness and flow velocity in a steep, glacier-fed mountain stream (Riedbach, Ct. Valais, Switzerland) with almost flume-like boundary conditions. Bed gradient increases along the 1 km study reach by roughly 1 order of magnitude (S = 3-41%), with a corresponding increase in streambed roughness, while flow discharge and width remain approximately constant due to the glacial runoff regime. Streambed roughness was characterized by semivariograms and standard deviations of point clouds derived from terrestrial laser scanning. Reach-averaged flow velocity was derived from dye tracer breakthrough curves measured by 10 fluorometers installed along the channel. Commonly used flow resistance approaches (Darcy-Weisbach equation and dimensionless hydraulic geometry) were used to relate the measured bulk velocity to bed characteristics. As a roughness measure, D84 yielded comparable results to more laborious measures derived from point clouds. Flow resistance behavior across this large range of steep slopes agreed with patterns established in previous studies for both lower-gradient and steep reaches, regardless of which roughness measures were used. We linked empirical critical shear stress approaches to the variable power equation for flow resistance to investigate the change of bed roughness with channel slope. The predicted increase in D84 with increasing channel slope was in good agreement with field observations.

  7. Primary production off Southern California relative to surface layer carbon budgets: A component of the California Basins Study, CaBS. Final report, [1 June 1989--14 November 1991

    SciTech Connect

    Trees, C.C.

    1994-04-22

    This study started on 1 June 1989 and ended 14 November 1991. Two moored in situ natural fluorometers were deployed in January 1990 to collect bio-optical data for one year, making ground truth measurements around the mooring during 4 cruises. This one-year time series would investigate how the short-term physical forcing aliases the long-term primary production record such that the apparent, larger interannual variability in the record is in reality ``noise`` due to short-term fluctuations in the rate of nutrient input to the euphotic zone. These continuous measurements from moored bio-optical instruments would also allow better estimates of the mean and variance in primary production in these waters than has previously been available from shipboard measurements, as well as, phytoplankton response to short-term physical events. Ancillary measurements that were made were: (1) characterization of the apparent and inherent optical properties, (2) photosynthetic pigment distributions using both HPLC and standard fluorometric methods, (3) carbon, hydrogen and nitrogen content of suspended particulate matter, (4) primary production using conventional {sup 14}C methods from simulated in situ experiments.

  8. In-situ optical and acoustical measurements of the buoyant cyanobacterium p. Rubescens: spatial and temporal distribution patterns.

    PubMed

    Hofmann, Hilmar; Peeters, Frank

    2013-01-01

    Optical (fluorescence) and acoustic in-situ techniques were tested in their ability to measure the spatial and temporal distribution of plankton in freshwater ecosystems with special emphasis on the harmful and buoyant cyanobacterium P. rubescens. Fluorescence was measured with the multi-spectral FluoroProbe (Moldaenke FluoroProbe, MFP) and a Seapoint Chlorophyll Fluorometer (SCF). In-situ measurements of the acoustic backscatter strength (ABS) were conducted with three different acoustic devices covering multiple acoustic frequencies (614 kHz ADCP, 2 MHz ADP, and 6 MHz ADV). The MFP provides a fast and reliable technique to measure fluorescence at different wavelengths in situ, which allows discriminating between P. rubescens and other phytoplankton species. All three acoustic devices are sensitive to P. rubescens even if other scatterers, e.g., zooplankton or suspended sediment, are present in the water column, because P. rubescens containing gas vesicles has a strong density difference and hence acoustic contrast to the ambient water and other scatterers. After calibration, the combination of optical and acoustical measurements not only allows qualitative and quantitative observation of P. rubescens, but also distinction between P. rubescens, other phytoplankton, and zooplankton. As the measuring devices can sample in situ at high rates they enable assessment of plankton distributions at high temporal (minutes) and spatial (decimeters) resolution or covering large temporal (seasonal) and spatial (basin scale) scales.

  9. [Performance index as an indicator of the physiological state of trees in urban forest ecosystems].

    PubMed

    Volgusheva, A A; Iakovleva, O V; Kukarskikh, G P; Riznichenko, G Iu; Krendeleva, T E

    2011-01-01

    Based on the measurements of fluorescence of bark chloroplasts by means of PAM and PEA fluorometers, the information capacity of the methods for assessing the physiological state of Tilia cordata L. from the maximum quantum efficiency of PS II photochemistry (Fv/Fm) and the performance index (PI) has been compared. The measurements were performed on annual shoots of linden trees growing in different environment. It was shown that the chlorophyll content in the bark of shoots growing near the busy urban street was twice less compared with trees growing out of the city. On the trees from the unsafe environment, a small decrease in the relative fluorescence variable (Fv/Fm) was registered, and there was a significant statistical deviation of this value compared to control trees. It was found that the PI and its constituent parameters calculated on the basis of light fluorescence induction curve (PEA-method) are more informative and allow one to recognize changes in the primary energy transformation processes in PS II when they are comparatively small. The results of our work show that PI can be used as a sensitive and a rapid test to evaluate the physiological state of trees and other plant objects even under minor environmental changes.

  10. Velocity, bathymetry, and transverse mixing characteristics of the Ohio River upstream from Cincinnati, Ohio, October 2004-March 2006

    USGS Publications Warehouse

    Koltun, G.F.; Ostheimer, Chad J.; Griffin, Michael S.

    2006-01-01

    Velocity, bathymetry, and transverse (cross-channel) mixing characteristics were studied in a 34-mile study reach of the Ohio River extending from the lower pool of the Captain Anthony Meldahl Lock and Dam, near Willow Grove, Ky, to just downstream from the confluence of the Licking and Ohio Rivers, near Newport, Ky. Information gathered in this study ultimately will be used to parameterize hydrodynamic and water-quality models that are being developed for the study reach. Velocity data were measured at an average cross-section spacing of about 2,200 feet by means of boat-mounted acoustic Doppler current profilers (ADCPs). ADCP data were postprocessed to create text files describing the three-dimensional velocity characteristics in each transect. Bathymetry data were measured at an average transect spacing of about 800 feet by means of a boat-mounted single-beam echosounder. Depth information obtained from the echosounder were postprocessed with water-surface slope and elevation information collected during the surveys to compute stream-bed elevations. The bathymetry data were written to text files formatted as a series of space-delimited x-, y-, and z-coordinates. Two separate dye-tracer studies were done on different days in overlapping stream segments in an 18.3-mile section of the study reach to assess transverse mixing characteristics in the Ohio River. Rhodamine WT dye was injected into the river at a constant rate, and concentrations were measured in downstream cross sections, generally spaced 1 to 2 miles apart. The dye was injected near the Kentucky shoreline during the first study and near the Ohio shoreline during the second study. Dye concentrations were measured along transects in the river by means of calibrated fluorometers equipped with flow-through chambers, automatic temperature compensation, and internal data loggers. The use of flow-through chambers permitted water to be pumped continuously out of the river from selected depths and through the

  11. Multifunctional System-on-Glass for Lab-on-Chip applications.

    PubMed

    Petrucci, G; Caputo, D; Lovecchio, N; Costantini, F; Legnini, I; Bozzoni, I; Nascetti, A; de Cesare, G

    2017-07-15

    Lab-on-Chip are miniaturized systems able to perform biomolecular analysis in shorter time and with lower reagent consumption than a standard laboratory. Their miniaturization interferes with the multiple functions that the biochemical procedures require. In order to address this issue, our paper presents, for the first time, the integration on a single glass substrate of different thin film technologies in order to develop a multifunctional platform suitable for on-chip thermal treatments and on-chip detection of biomolecules. The proposed System on-Glass hosts thin metal films acting as heating sources; hydrogenated amorphous silicon diodes acting both as temperature sensors to monitor the temperature distribution and photosensors for the on-chip detection and a ground plane ensuring that the heater operation does not affect the photodiode currents. The sequence of the technological steps, the deposition temperatures of the thin films and the parameters of the photolithographic processes have been optimized in order to overcome all the issues of the technological integration. The device has been designed, fabricated and tested for the implementation of DNA amplification through the Polymerase Chain Reaction (PCR) with thermal cycling among three different temperatures on a single site. The glass has been connected to an electronic system that drives the heaters and controls the temperature and light sensors. It has been optically and thermally coupled with another glass hosting a microfluidic network made in polydimethylsiloxane that includes thermally actuated microvalves and a PCR process chamber. The successful DNA amplification has been verified off-chip by using a standard fluorometer.

  12. Photosynthesis and photosynthetic pigments in the flagellate Euglena gracilis - as sensitive endpoints for toxicity evaluation of liquid detergents.

    PubMed

    Azizullah, Azizullah; Richter, Peter; Häder, Donat-Peter

    2014-04-05

    The present study was designed to validate the applicability of photosynthetic performance using a PAM fluorometer and photosynthetic pigments in Euglena gracilis as endpoint parameters in toxicity assessment of liquid detergents using a dish washing liquid detergent during short- (0-72h) and long-term (7days) exposure. In short-term experiments, the detergent affected the photosynthetic efficiency with EC50 values (calculated for Fv/Fm) of 22.07%, 7.27%, 1.4% and 2.34%, after 0, 1, 24 and 72h, respectively. The relative electron transport rate (rETR) and quantum yield measured with increasing irradiances were also inhibited by the detergent. The most severe effect of the detergent on the light-harvesting pigments (μgmL(-1)) was observed after 72h where chlorophyll a and total carotenoids were decreased at concentrations above 0.1% and chlorophyll b was decreased at concentrations above 0.5%. In long-term experiments, the detergent reduced the photosynthetic efficiency of cultures giving an EC50 value of 0.867% for Fv/Fm. rETR and quantum yield with increasing irradiance were shown to be adversely affected at concentrations of 0.1% or above. A decrease in chlorophyll a and total carotenoids (μgmL(-1)) was observed at concentrations of 0.05% detergent or above. Chlorophyll b was shown to be comparatively less affected by detergent stress, and a significant decrease was observed at concentrations of 0.5% or above. However, there was no prominent decrease in per cell (Euglena) concentration of any pigment. It can be concluded that photosynthesis and light-harvesting pigments in E. gracilis were sensitive to detergent stress and can be used as sensitive parameters in toxicity assessment of detergents in aquatic environments.

  13. Low cost quantitative digital imaging as an alternative to qualitative in vivo bioassays for analysis of active aflatoxin B1.

    PubMed

    Rasooly, Reuven; Do, Paula M; Hernlem, Bradley J

    2016-06-15

    Aflatoxin B1 (AFB1) producing fungi contaminate food and feed and are a major health concern. To minimize the sources and incidence of AFB1 illness there is a need to develop affordable, sensitive mobile devices for detection of active AFB1. In the present study we used a low cost fluorescence detector and describe two quantitative assays for detection of detoxified and active AFB1 demonstrating that AFB1 concentration can be measured as intensity of fluorescence. When the assay plate containing increasing concentrations of AFB1 is illuminated with a 366 nm ultraviolet lamp, AFB1 molecules absorb photons and emit blue light with peak wavelength of 432 nm. The fluorescence intensity increased in dose dependent manner. However, this method cannot distinguish between active AFB1 which poses a threat to health, and the detoxified AFB1 which exhibits no toxicity. To measure the toxin activity, we used a cell based assay that makes quantification more robust and is capable of detecting multiple samples simultaneously. It is an alternative to the qualitative duckling bioassay which is the "gold-standard" assay currently being used for quantitative analysis of active AFB1. AFB1 was incubated with transduced Vero cells expressing the green fluorescence protein (GFP) gene. After excitation with blue light at 475 nm, cells emitted green light with emission peak at 509 nm. The result shows that AFB1 inhibits protein expression in a concentration dependent manner resulting in proportionately less GFP fluorescence in cells exposed to AFB1. The result also indicates strong positive linear relationship with R(2)=0.90 between the low cost CCD camera and a fluorometer, which costs 100 times more than a CCD camera. This new analytical method for measuring active AFB1 is low in cost and combined with in vitro assay, is quantitative. It also does not require the use of animals and may be useful especially for laboratories in regions with limited resources.

  14. Production of volatile organic compounds in cultures of cryptophytes

    NASA Astrophysics Data System (ADS)

    Yamakoshi, T.; Kurihara, M.; Hashimoto, S.

    2010-12-01

    Volatile organic compounds (VOCs) are known to be produced by macroalgae, phytoplankton and bacteria in the ocean. Some phytoplankton species are known for the production of VOCs such as halomethanes and isoprene in cultures. To discuss the diversity of VOCs production among phytoplankton species, we incubated the strains of cryptophytes and measured concentrations of VOCs and chlorophyll a. Because VOCs productions of cryptophytes were poorly understood, we selected them to cover the lack of data for VOCs production. Phytoplankton cultures were grown in autoclaved f/2-Si medium with GF/F filtered aged seawater. Culture temperature and light conditions were 24.1 ± 0.2°C and 78 ± 4 μE m-2 s-1 (1 E = 1 mol of photons) from full-spectrum vita-lite fluorescent lamp (12 h light:12 h dark cycle). VOCs concentrations in the medium were measured using a purge and trap (Tekmar PT 5000J)- gas chromatograph (Agilent 6890N)- mass spectrometer (Agilent 5973N). The concentrations of chlorophyll a was also measured using fluorometer (Turner TD-700). Isoprene concentrations were increased to 290 pmol L-1 during the exponential phase in Rhodomonas salina culture. Isoprene production rate was 0.78 μmol g chl.a-1 day-1. This value is within the range of isoprene production by other phytoplankton species reported in the previous paper. As for halomethanes, dibromomethane concentrations were increased during the incubation time. Some iodohalomethanes were also increased during the death phase. We are currently examining the production of halomethanes in other strains of Cryptophyta.

  15. Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

    NASA Astrophysics Data System (ADS)

    Sasaki, H.; Matsuno, K.; Fujiwara, A.; Onuka, M.; Yamaguchi, A.; Ueno, H.; Watanuki, Y.; Kikuchi, T.

    2015-11-01

    The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

  16. Observations of a phytoplankton spring bloom onset triggered by a density front in NW Mediterranean

    NASA Astrophysics Data System (ADS)

    Olita, A.; Sparnocchia, S.; Cusí, S.; Fazioli, L.; Sorgente, R.; Tintoré, J.; Ribotti, A.

    2014-07-01

    Phytoplankton blooms in the northwestern Mediterranean Sea are seasonal events that mainly occur in a specific area comprising the Gulf of Lion and the Provençal basin, where they are promoted by a general cyclonic circulation, strong wind-driven mixing and subsequent re-stratification of the water column. At the southern boundary of this area, a persistent density front known as the north Balearic front can be found. The front is presumed to cause an early phytoplankton bloom in its vicinity because (a) it enhances the transport of nutrients into the euphotic layer and (b) it promotes the speedy re-stratification of the water column (through frontal instabilities). In February and March 2013, a glider, equipped with a CTD (conductivity, temperature, and depth device) and a fluorometer, was deployed on a mission that took it from the Balearic Islands to Sardinia and back. The frontal zone was crossed twice, once during the outbound leg and the once on the return leg. The data provided by the glider clearly showed the onset of a bloom soon after a decrease in wind-driven turbulent convection and mixing. The in situ observations were supported and confirmed by satellite imagery. It is shown that frontal dynamics play a key role in the promotion and acceleration of re-stratification, which is a necessary pre-conditioning factor for the onset of blooms much like other relevant processes such as an enhanced biological pump. Swift re-stratification stimulates new production by inhibiting mixing. Finally, viewing the blooming phenomenon from a regional perspective, it seems that Sverdrup's critical depth model applies in the northern well-mixed area whereas, in the south, front-related re-stratification seems to be the principal cause.

  17. Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

    PubMed

    Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

    2008-06-01

    Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

  18. Characterization of reach velocity and detailed geometry in well-vegetated, high-gradient streams

    NASA Astrophysics Data System (ADS)

    Yochum, S. E.; Bledsoe, B. P.; David, G. C.; Wohl, E. E.

    2008-12-01

    We developed field procedures for relating complex spatial patterns in channel geometry and roughness elements to flow resistance of mountain streams. High gradient, forested stream reaches in the U.S. Forest Service's Fraser Experimental Forest, of Colorado, were characterized using Rhodamine WT dye tracing for average reach velocity and LiDAR scans for reach geometry. The dye tracing technique consists of an injection of 20 percent rhodamine WT dye solution, with concentrations measured every second at the upstream and downstream limits of the reach using two Turner Designs Cyclops 7 fluorometers linked with two Campbell Scientific CR10X dataloggers and a calibration relating voltage output with concentration. Reach-averaged velocity was computed with the thalweg distance and both the time between peaks and the time between center of mass of the tracer pulse. Geometric data for points above the low flow water level were collected using a tripod-mounted Leica HDS LiDAR scanner. Reaches were scanned from multiple directions to minimize shadow. Targets were set up over at least two control points, for each scan, to register the scan into a consistent coordinate system. The LiDAR scans were combined with detailed total station surveys of features below the water surface. With the joining of multiple data sources, proper survey control was essential for data compatibility. The LiDAR and total station bed surveys were merged into a common pointcloud and the resulting data were cleaned to improve clarity. From this merged and cleaned pointcloud, a wide variety of geometric characteristics can be measured in the office, as the need arises. Specific characteristics will support such analyses as the determination of reach section hydraulic variables, and the use of spatial-statistical, tracer skewness and bank/bed form as indicators of roughness.

  19. Level of inflammatory cytokines in rheumatoid arthritis patients: Correlation with 25-hydroxy vitamin D and reactive oxygen species.

    PubMed

    Mateen, Somaiya; Moin, Shagufta; Shahzad, Sumayya; Khan, Abdul Qayyum

    2017-01-01

    Rheumatoid arthritis (RA) is an autoimmune inflammatory disorder. Reactive oxygen species (ROS) and pro-inflammatory cytokines have been believed to be involved in the etiopathogenesis of the disease. The aim of the study was to determine the correlation of inflammatory cytokines with 25-hydroxy vitamin D and ROS. 100 RA patients and 50 healthy age and sex matched individuals were included in the study. Patients were further divided on the basis of presence or absence of rheumatoid factor and disease severity. Serum 25-hydroxy vitamin D levels were monitored by chemiluminescent immunoassay. 10% hematocrit was used to detect the level of ROS by spectro fluorometer. The levels of inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-10 and IL-17) were determined in plasma by ELISA. The level of 25-hydroxy vitamin D was found to be decreased in RA patients in comparison to the control group. However the level of ROS and inflammatory cytokines were found to be elevated in RA patients in comparison with the healthy controls, with the increase being more pronounced in seropositive and RA patients having high disease severity. Inflammatory cytokines showed negative correlation with 25-hydroxy vitamin D and positive correlation with ROS. This study for the first time shows the association of inflammatory cytokines with 25-hydroxy vitamin D and ROS in RA patients. The results suggest that 25-hydroxy vitamin D being an immune modulator is decreased in the serum of RA patients. Further ROS and cytokines play an important role in the pathogenesis of RA and are responsible for increasing the severity of disease.

  20. Aflatoxin B1 contamination of traditionally processed peanuts butter for human consumption in Sudan.

    PubMed

    Elshafie, Sana Z B; ElMubarak, Abdullah; El-Nagerabi, Saifeldin A F; Elshafie, Abdulkadir E

    2011-06-01

    A survey was carried out to detect the presence of aflatoxin B(1) in 60 duplicated samples (120 samples) of peanuts butter purchased from the local markets and other traditionally prepared and distributed by the street sellers in Khartoum state, Sudan. AflaTest-P affinity column was used to extract the toxin from the samples, and the concentration was measured by calibrated Vicam fluorometer. Aflatoxin B(1) was detected at variable levels in 100% of the screened samples. Traditionally prepared samples showed the highest incidence of aflatoxin B(1) which is above the internationally regulated tolerance levels (5-20 ppb). The means and the ranges of the aflatoxin B(1) recovered were as follows: 63.9 ppb (29-128 ppb), 54.5 ppb (21-131 ppb) and 101 ppb (17-170 ppb) for samples collected from Khartoum, Khartoum North and Omdurman areas, respectively. Samples from retail stores presented relatively low aflatoxin B(1) incidences 14.5 ppb (1-57 ppb), but only 30% of the samples revealed aflatoxin level below 10 ppb. Laboratory segregated and carefully prepared butter from good grade nuts showed the lowest levels of this toxin (3.3 ppb; 2-6 ppb). The results showed that peanuts butter prepared by the street sellers and distributed by the retail stores are evidently hazardous to human health. There is therefore urgent need for strong form of quality control measures and public awareness. The use of excellent grade peanuts and care during processing and storage are priority.

  1. Sudden Collapse of Vacuoles in Saintpaulia sp. Palisade Cells Induced by a Rapid Temperature Decrease

    PubMed Central

    Kadohama, Noriaki; Goh, Tatsuaki; Ohnishi, Miwa; Fukaki, Hidehiro; Mimura, Tetsuro; Suzuki, Yoshihiro

    2013-01-01

    It is well known that saintpaulia leaf is damaged by the rapid temperature decrease when cold water is irrigated onto the leaf surface. We investigated this temperature sensitivity and the mechanisms of leaf damage in saintpaulia (Saintpaulia sp. cv. ‘Iceberg’) and other Gesneriaceae plants. Saintpaulia leaves were damaged and discolored when subjected to a rapid decrease in temperature, but not when the temperature was decreased gradually. Sensitivity to rapid temperature decrease increased within 10 to 20 min during pre-incubation at higher temperature. Injury was restricted to the palisade mesophyll cells, where there was an obvious change in the color of the chloroplasts. During a rapid temperature decrease, chlorophyll fluorescence monitored by a pulse amplitude modulated fluorometer diminished and did not recover even after rewarming to the initial temperature. Isolated chloroplasts were not directly affected by the rapid temperature decrease. Intracellular pH was monitored with a pH-dependent fluorescent dye. In palisade mesophyll cells damaged by rapid temperature decrease, the cytosolic pH decreased and the vacuolar membrane collapsed soon after a temperature decrease. In isolated chloroplasts, chlorophyll fluorescence declined when the pH of the medium was lowered. These results suggest that a rapid temperature decrease directly or indirectly affects the vacuolar membrane, resulting in a pH change in the cytosol that subsequently affects the chloroplasts in palisade mesophyll cells. We further confirmed that the same physiological damage occurs in other Gesneriaceae plants. These results strongly suggested that the vacuoles of palisade mesophyll cells collapsed during the initial phase of leaf injury. PMID:23451194

  2. Sudden collapse of vacuoles in Saintpaulia sp. palisade cells induced by a rapid temperature decrease.

    PubMed

    Kadohama, Noriaki; Goh, Tatsuaki; Ohnishi, Miwa; Fukaki, Hidehiro; Mimura, Tetsuro; Suzuki, Yoshihiro

    2013-01-01

    It is well known that saintpaulia leaf is damaged by the rapid temperature decrease when cold water is irrigated onto the leaf surface. We investigated this temperature sensitivity and the mechanisms of leaf damage in saintpaulia (Saintpaulia sp. cv. 'Iceberg') and other Gesneriaceae plants. Saintpaulia leaves were damaged and discolored when subjected to a rapid decrease in temperature, but not when the temperature was decreased gradually. Sensitivity to rapid temperature decrease increased within 10 to 20 min during pre-incubation at higher temperature. Injury was restricted to the palisade mesophyll cells, where there was an obvious change in the color of the chloroplasts. During a rapid temperature decrease, chlorophyll fluorescence monitored by a pulse amplitude modulated fluorometer diminished and did not recover even after rewarming to the initial temperature. Isolated chloroplasts were not directly affected by the rapid temperature decrease. Intracellular pH was monitored with a pH-dependent fluorescent dye. In palisade mesophyll cells damaged by rapid temperature decrease, the cytosolic pH decreased and the vacuolar membrane collapsed soon after a temperature decrease. In isolated chloroplasts, chlorophyll fluorescence declined when the pH of the medium was lowered. These results suggest that a rapid temperature decrease directly or indirectly affects the vacuolar membrane, resulting in a pH change in the cytosol that subsequently affects the chloroplasts in palisade mesophyll cells. We further confirmed that the same physiological damage occurs in other Gesneriaceae plants. These results strongly suggested that the vacuoles of palisade mesophyll cells collapsed during the initial phase of leaf injury.

  3. Comparison of methods for circulating cell-free DNA isolation using blood from cancer patients: impact on biomarker testing

    PubMed Central

    Pérez-Barrios, Clara; Nieto-Alcolado, Irene; Torrente, María; Jiménez-Sánchez, Carolina; Calvo, Virginia; Gutierrez-Sanz, Lourdes; Palka, Magda; Donoso-Navarro, Encarnación; Provencio, Mariano

    2016-01-01

    Background The implementation of liquid biopsy for biomarker testing and response to treatment monitoring in cancer patients would presumable increase laboratory throughput, requiring the development of automated methods for circulating free DNA (cfDNA) isolation. Methods The present study compares the MagNA Pure Compact (MPC) Nucleic Acid Isolation Kit I and Maxwell® RSC (MR) ccfDNA Plasma Kit and the later with QIAamp Circulating Nucleid Acid (QCNA) Kit using 57 plasma samples from cancer patients. cfDNA concentration was measured using the Qubit fluorometer. DNA fragments lengt were assessed using the Agilent 2100 Bioanalyzer. Circulating tumor DNA (ctDNA) was quantified by digital PCR (dPCR). Results Firstly, we observed that MPC method significantly extracted less cfDNA than MR (P<0.0001). However, there were no significant differences in extraction yields of QCNA and MR kits. cfDNA isolation yield was also associated with tumor stage but not with tumor location. Secondly, an oligonucleosomal DNA ladder pattern was observed in 88% of the samples and significant differences in the recovery of mono-, di- and tri-nucleosomes DNA fragments were observed between MPC and MR methodologies. Finally, tumor mutation quantification on cfDNA was performed on 38 paired samples using digital PCR. Mutant allele fractions (MAFs) between paired samples were not significantly different. Conclusions Methods for isolation of cfDNA can affect DNA yield and molecular weight fractions recovery. These observations should be taken into account for cfDNA analysis in routine clinical practice. PMID:28149760

  4. Iron specificity of a biosensor based on fluorescent pyoverdin immobilized in sol-gel glass

    PubMed Central

    2011-01-01

    Two current technologies used in biosensor development are very promising: 1. The sol-gel process of making microporous glass at room temperature, and 2. Using a fluorescent compound that undergoes fluorescence quenching in response to a specific analyte. These technologies have been combined to produce an iron biosensor. To optimize the iron (II or III) specificity of an iron biosensor, pyoverdin (a fluorescent siderophore produced by Pseudomonas spp.) was immobilized in 3 formulations of porous sol-gel glass. The formulations, A, B, and C, varied in the amount of water added, resulting in respective R values (molar ratio of water:silicon) of 5.6, 8.2, and 10.8. Pyoverdin-doped sol-gel pellets were placed in a flow cell in a fluorometer and the fluorescence quenching was measured as pellets were exposed to 0.28 - 0.56 mM iron (II or III). After 10 minutes of exposure to iron, ferrous ion caused a small fluorescence quenching (89 - 97% of the initial fluorescence, over the range of iron tested) while ferric ion caused much greater quenching (65 - 88%). The most specific and linear response was observed for pyoverdin immobilized in sol-gel C. In contrast, a solution of pyoverdin (3.0 μM) exposed to iron (II or III) for 10 minutes showed an increase in fluorescence (101 - 114%) at low ferrous concentrations (0.45 - 2.18 μM) while exposure to all ferric ion concentrations (0.45 - 3.03 μM) caused quenching. In summary, the iron specificity of pyoverdin was improved by immobilizing it in sol-gel glass C. PMID:21554740

  5. The microbial mats of Pavilion Lake microbialites: examining the relationship between photosynthesis and carbonate precipitation

    NASA Astrophysics Data System (ADS)

    Lim, D. S. S.; Hawes, I.; Mackey, T. J.; Brady, A. L.; Biddle, J.; Andersen, D. T.; Belan, M.; Slater, G.; Abercromby, A.; Squyres, S. W.; Delaney, M.; Haberle, C. W.; Cardman, Z.

    2014-12-01

    Pavilion Lake in British Columbia, Canada is an ultra-oligotrophic lake that has abundant microbialite growth. Recent research has shown that photoautotrophic microbial communities are important to modern microbialite development in Pavilion Lake. However, questions remain as to the relationship between changing light levels within the lake, variation in microbialite macro-structure, microbial consortia, and the preservation of associated biosignatures within the microbialite fabrics. The 2014 Pavilion Lake Research Project (PLRP) field program was focused on data gathering to understand these complex relationships by determining if a) light is the immediate limit to photosynthetic activity and, if so, if light is distributed around microbialites in ways that are consistent with emergent microbialite structure; and b) if at more local scales, the filamentous pink and green cyanobacterial nodular colonies identified in previous PLRP studies are centers of photosynthetic activity that create pH conditions suitable for carbonate precipitation. A diver-deployed pulse-amplitude modulated (PAM) fluorometer was used to collect synoptic in situ measurements of fluorescence yield and irradiance and across microbialites, focusing on comparing flat and vertical structural elements at a range of sites and depths. As well, we collected time series measurements of photosynthetic activity and irradiance at a set depth of 18 m across three different regions in Pavilion Lake. Our initial findings suggest that all microbialite surfaces are primarily light-limited regardless of depth or location within the lake. Shore based PAM fluorometry and microelectrode profiling of diver-collected samples suggest that pink and green nodules have different photosynthetic properties and pH profiles, and that nodular growth is likely to be the primary route of calcification due to the gelatinous covering the nodule creates. On-going tests for molecular signatures and isotopic shifts will allow for

  6. DNA as sensors and imaging agents for metal ions.

    PubMed

    Xiang, Yu; Lu, Yi

    2014-02-17

    Increasing interest in detecting metal ions in many chemical and biomedical fields has created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal-ion-dependent DNAzymes and metal-ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attachment of these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detection. These sensors are highly sensitive (with a detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of "dipstick tests", portable fluorometers, computer-readable disks, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal-ion sensing and imaging in many fields of applications.

  7. Net Fluorescein Flux Across Corneal Endothelium Strongly Suggests Fluid Transport is due to Electro-osmosis.

    PubMed

    Sanchez, J M; Cacace, V; Kusnier, C F; Nelson, R; Rubashkin, A A; Iserovich, P; Fischbarg, J

    2016-08-01

    We have presented prior evidence suggesting that fluid transport results from electro-osmosis at the intercellular junctions of the corneal endothelium. Such phenomenon ought to drag other extracellular solutes. We have investigated this using fluorescein-Na2 as an extracellular marker. We measured unidirectional fluxes across layers of cultured human corneal endothelial (HCE) cells. SV-40-transformed HCE layers were grown to confluence on permeable membrane inserts. The medium was DMEM with high glucose and no phenol red. Fluorescein-labeled medium was placed either on the basolateral or the apical side of the inserts; the other side carried unlabeled medium. The inserts were held in a CO2 incubator for 1 h (at 37 °C), after which the entire volume of the unlabeled side was collected. After that, label was placed on the opposite side, and the corresponding paired sample was collected after another hour. Fluorescein counts were determined with a (Photon Technology) DeltaScan fluorometer (excitation 380 nm; emission 550 nm; 2 nm bwth). Samples were read for 60 s. The cells utilized are known to transport fluid from the basolateral to the apical side, just as they do in vivo in several species. We used 4 inserts for influx and efflux (total: 20 1-h periods). We found a net flux of fluorescein from the basolateral to the apical side. The flux ratio was 1.104 ± 0.056. That difference was statistically significant (p = 0.00006, t test, paired samples). The endothelium has a definite restriction at the junctions. Hence, an asymmetry in unidirectional fluxes cannot arise from osmosis, and can only point instead to paracellular solvent drag. We suggest, once more, that such drag is due to electro-osmotic coupling at the paracellular junctions.

  8. Optical properties of Colored Dissolved Organic Matter (CDOM) on the East Siberian shelf

    NASA Astrophysics Data System (ADS)

    Semiletov, I. P.; Pugach, S.; Pipko, I.

    2015-12-01

    The Great Siberian Rivers integrate meteorological and hydrological changes in their watersheds and play a significant role in the physical and biogeochemical regime of the Arctic Ocean. Given the magnitude of Siberian Arctic dissolved organic matter (DOM) export and the uncertain extent to which it is degraded to greenhouse gases, intensified studies to better quantify and understand this large carbon pool and processes acting on it are urgently needed. The East Siberian Arctic shelf is characterized by the highest rate of coastal erosion and significant volume of the riverine discharge which derived terrigenous DOM in the Arctic Ocean. DOM plays a significant role in freshwater and marine aquatic ecosystems including its effects on nutrients and carbon cycling. The colored fraction of DOM, CDOM, directly affects the quantity and spectral quality of available light, thereby impaction both primary production and UV exposure in aquatic ecosystems. Since 2003 we measure CDOM in the East Siberian Arctic Seas (ESAS) in situ using the WETStar fluorometer which doesn't require prefiltration of sample. Combined analysis of CDOM and DOC data obtained at near-annual basis in (2003-2011) demonstrate a high degree of correlation between these parameters. For all the measured samples taken during the ISSS cruises (2003, 2004, 2005, 2008, 2011), there is an overall linear relationship between DOC concentration, CDOM, and salinity. Here we report the spatial-time variability of river-borne DOM in the ESAS using CDOM as a proxy parameter. Higher absorption coefficients (a254), spectral slope parameter over range 275-295 nm (S275-295) and CDOM concentrations reflect the dominant contribution of terrigenous DOM. It is shown that the attenuation light coefficient in the shallow ESAS is mostly determined by riverine CDOM.

  9. Effective light absorption and absolute electron transport rates in the coral Pocillopora damicornis.

    PubMed

    Szabó, Milán; Wangpraseurt, Daniel; Tamburic, Bojan; Larkum, Anthony W D; Schreiber, Ulrich; Suggett, David J; Kühl, Michael; Ralph, Peter J

    2014-10-01

    Pulse Amplitude Modulation (PAM) fluorometry has been widely used to estimate the relative photosynthetic efficiency of corals. However, both the optical properties of intact corals as well as past technical constrains to PAM fluorometers have prevented calculations of the electron turnover rate of PSII. We used a new Multi-colour PAM (MC-PAM) in parallel with light microsensors to determine for the first time the wavelength-specific effective absorption cross-section of PSII photochemistry, σII(λ), and thus PAM-based absolute electron transport rates of the coral photosymbiont Symbiodinium both in culture and in hospite in the coral Pocillopora damicornis. In both cases, σII of Symbiodinium was highest in the blue spectral region and showed a progressive decrease towards red wavelengths. Absolute values for σII at 440 nm were up to 1.5-times higher in culture than in hospite. Scalar irradiance within the living coral tissue was reduced by 20% in the blue when compared to the incident downwelling irradiance. Absolute electron transport rates of P. damicornis at 440 nm revealed a maximum PSII turnover rate of ca. 250 electrons PSII(-1) s(-1), consistent with one PSII turnover for every 4 photons absorbed by PSII; this likely reflects the limiting steps in electron transfer between PSII and PSI. Our results show that optical properties of the coral host strongly affect light use efficiency of Symbiodinium. Therefore, relative electron transport rates do not reflect the productivity rates (or indeed how the photosynthesis-light response is parameterised). Here we provide a non-invasive approach to estimate absolute electron transport rates in corals. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  10. Bio-optical properties of Porsnagerfjorden (Norway) waters based on data collected in 2014 and 2015

    NASA Astrophysics Data System (ADS)

    Białogrodzka, Jagoda; Stramska, Małgorzata; Burska, Dorota; Ficek, Dariusz; Stoń-Egiert, Joanna; Winogradow, Aleksandra

    2016-04-01

    Oceanographic data collected in the Arctic are valuable in view of the role of this region in the studies on global climate change and the fact that historically the number of in situ measurements is relatively low. Porsangerfjorden, Norway, is an example of oceanic basin with case 2 water according to the optical classification. Optical data from coastal seas are difficult in interpretation because the concentrations of optically important components can be high, variable, and not covarying with each other. Porsanger Fjord can be divided into three basins: inner, middle and outer, where physical and bio-optical properties of water masses differ. We collected optical data and water samples for phytoplankton pigments, dissolved organic matter, particulate (POC) and dissolved (DOC) organic carbon, and particulate inorganic carbon (PIC) during our two summer expeditions in 2014 and 2015. In this presentation we focus on data collected with WETLabs' ac-9 and ac-s spectrophotometers and ECO-Triplet and ECO-Triplet-w fluorometers. Concurrently with in situ optical measurements water samples were collected in situ and soon afterwards they were filtered in the laboratory at the station, stored and transported for further processing in Poland. Our analysis includes 146 of in situ measurements and discrete water samples: 62 of POC, 52 of PIC, 33 of DOC, 68 of dissolved organic matter and 89 of phytoplankton pigments. During our analysis we compare chlorophyll (Chl_a), dissolved organic matter (CDOM) and carbon concentrations with in situ collected inherent optical properties of sea water to find empirical proxies allowing to estimate various water component concentrations from optical data. Application of these proxies to available bio-optical data allowed us to derive spatial distribution of these water constituents and their variability. This work was funded by the Norway Grants (NCBR contract No. 201985, project NORDFLUX).

  11. Experimental design and quality assurance: in situ fluorescence instrumentation

    USGS Publications Warehouse

    Conmy, Robyn N.; Del Castillo, Carlos E.; Downing, Bryan D.; Chen, Robert F.

    2014-01-01

    Both instrument design and capabilities of fluorescence spectroscopy have greatly advanced over the last several decades. Advancements include solid-state excitation sources, integration of fiber optic technology, highly sensitive multichannel detectors, rapid-scan monochromators, sensitive spectral correction techniques, and improve data manipulation software (Christian et al., 1981, Lochmuller and Saavedra, 1986; Cabniss and Shuman, 1987; Lakowicz, 2006; Hudson et al., 2007). The cumulative effect of these improvements have pushed the limits and expanded the application of fluorescence techniques to numerous scientific research fields. One of the more powerful advancements is the ability to obtain in situ fluorescence measurements of natural waters (Moore, 1994). The development of submersible fluorescence instruments has been made possible by component miniaturization and power reduction including advances in light sources technologies (light-emitting diodes, xenon lamps, ultraviolet [UV] lasers) and the compatible integration of new optical instruments with various sampling platforms (Twardowski et at., 2005 and references therein). The development of robust field sensors skirt the need for cumbersome and or time-consuming filtration techniques, the potential artifacts associated with sample storage, and coarse sampling designs by increasing spatiotemporal resolution (Chen, 1999; Robinson and Glenn, 1999). The ability to obtain rapid, high-quality, highly sensitive measurements over steep gradients has revolutionized investigations of dissolved organic matter (DOM) optical properties, thereby enabling researchers to address novel biogeochemical questions regarding colored or chromophoric DOM (CDOM). This chapter is dedicated to the origin, design, calibration, and use of in situ field fluorometers. It will serve as a review of considerations to be accounted for during the operation of fluorescence field sensors and call attention to areas of concern when making

  12. Combined effects of lanthanum ion and acid rain on growth, photosynthesis and chloroplast ultrastructure in soybean seedlings.

    PubMed

    Wen, Kejia; Liang, Chanjuan; Wang, Lihong; Hu, Gang; Zhou, Qing

    2011-07-01

    Rare earth elements (REEs) have been accumulated in the agricultural environment. Acid rain is a serious environmental issue. In the present work, the effects of lanthanum ion (La(3+)) and acid rain on the growth, photosynthesis and chloroplast ultrastructure in soybean seedlings were investigated using the gas exchange measurements system, chlorophyll fluorometer, transmission electron microscopy and some biochemical techniques. It was found that although the growth and photosynthesis of soybean seedlings treated with the low concentration of La(3+) was improved, the growth and photosynthesis of soybean seedlings were obviously inhibited in the combined treatment with the low concentration of La(3+) and acid rain. At the same time, the chloroplast ultrastructure in the cell of soybean seedlings was destroyed. Under the combined treatment with the high concentration of La(3+) and acid rain, the chloroplast ultrastructure in the cell of soybean seedlings was seriously destroyed, and the growth and of photosynthesis were greatly decreased compared with those of the control, the single treatment with the high concentration of La(3+) and the single treatment with acid rain, respectively. The degree of decrease and destruction on chloroplast ultrastructure depended on the increases in the concentration of La(3+) and acid rain (H(+)). In conclusion, the combined pollution of La(3+) and acid rain obviously destroyed the chloroplast ultrastructure of cell and aggravated the harmful effect of the single La(3+) and acid rain on soybean seedlings. As a new combined pollutant, the harmful effect of REEs ions and acid rain on plant should be paid attention to. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. [Effects of suspended silts in waters on the growth and chlorophyll fluorescence characteristics of Hydrilla verticillata].

    PubMed

    Li, Qiang; Wang, Guo-Xiang

    2009-10-01

    Silt particles smaller than 100 microm in diameter were used to make the waters with a turbidity of 30 NTU, 60 NTU, and 90 NTU. Hydrilla verticillata seedlings were planted in the turbid waters, and their branch length, branch number, and fresh mass were measured at definite periods of time. In the meanwhile, the leaf chlorophyll fluorescence parameters were determined in situ by a submersible pulse-amplitude modulated (PAM) fluorometer (Walz GmbH, Effeltrich, Germany). With the increase of water turbidity, the branch number of the seedlings decreased remarkably, biomass also decreased, but branch length increased significantly. In turbid waters, the Fv/Fm value decreased with time, but was still higher than that in the control waters. Under the actinic light of 17 micromol x m(-2) x s(-1) PPFD, the effective quantum yield (DeltaFv'/Fm') of seedling leaves on the 60th day in the waters with turbidity of 30 NTU, 60 NTU, and 90 NTU increased by 48.9%, 36.8%, and 17.2% (P < 0.01), and the relative electron transport rate (rETR) increased by 56.7%, 42.2%, and 21.4% (P < 0.01), respectively, compared with those on the 30th day. However, under the actinic light of 104 micromol x m(-2) s(-1) PPFD, the DeltaFv'/Fm', qp, and rETR on the 60th day decreased significantly, and the heat dissipation capability (qN) also reduced evidently. All the results suggested that the H. verticillata seedlings in turbid waters could adapt to low light environment, but their leaves were easy to be damaged under high light intensity. Therefore, it would be possible to introduce H. verticillata seedlings in shallow turbid waters.

  14. Mitochondrial function in vivo evaluated by NADH fluorescence: from animal models to human studies.

    PubMed

    Mayevsky, Avraham; Rogatsky, Gennady G

    2007-02-01

    Normal mitochondrial function is a critical factor in maintaining cellular homeostasis in various organs of the body. Due to the involvement of mitochondrial dysfunction in many pathological states, the real-time in vivo monitoring of the mitochondrial metabolic state is crucially important. This type of monitoring in animal models as well as in patients provides real-time data that can help interpret experimental results or optimize patient treatment. The goals of the present review are the following: 1) to provide an historical overview of NADH fluorescence monitoring and its physiological significance; 2) to present the solid scientific ground underlying NADH fluorescence measurements based on published materials; 3) to provide the reader with basic information on the methodologies used in the past and the current state of the art fluorometers; and 4) to clarify the various factors affecting monitored signals, including artifacts. The large numbers of publications by different groups testify to the valuable information gathered in various experimental conditions. The monitoring of NADH levels in the tissue provides the most important information on the metabolic state of the mitochondria in terms of energy production and intracellular oxygen levels. Although NADH signals are not calibrated in absolute units, their trend monitoring is important for the interpretation of physiological or pathological situations. To understand tissue function better, the multiparametric approach has been developed where NADH serves as the key parameter. The development of new light sources in UV and visible spectra has led to the development of small compact units applicable in clinical conditions for better diagnosis of patients.

  15. High-frequency in situ optical measurements during a storm event: Assessing relationships between dissolved organic matter, sediment concentrations, and hydrologic processes

    USGS Publications Warehouse

    Saraceno, John F.; Pellerin, Brian A.; Downing, Bryan D.; Boss, Emmanuel; Bachand, Philip A. M.; Bergamaschi, Brian A.

    2009-01-01

    Dissolved organic matter (DOM) dynamics during storm events has received considerable attention in forested watersheds, but the extent to which storms impart rapid changes in DOM concentration and composition in highly disturbed agricultural watersheds remains poorly understood. In this study, we used identical in situ optical sensors for DOM fluorescence (FDOM) with and without filtration to continuously evaluate surface water DOM dynamics in a 415 km2agricultural watershed over a 4 week period containing a short-duration rainfall event. Peak turbidity preceded peak discharge by 4 h and increased by over 2 orders of magnitude, while the peak filtered FDOM lagged behind peak turbidity by 15 h. FDOM values reported using the filtered in situ fluorometer increased nearly fourfold and were highly correlated with dissolved organic carbon (DOC) concentrations (r2 = 0.97), providing a highly resolved proxy for DOC throughout the study period. Discrete optical properties including specific UV absorbance (SUVA254), spectral slope (S290–350), and fluorescence index (FI) were also strongly correlated with in situ FDOM and indicate a shift toward aromatic, high molecular weight DOM from terrestrially derived sources during the storm. The lag of the peak in FDOM behind peak discharge presumably reflects the draining of watershed soils from natural and agricultural landscapes. Field and experimental evidence showed that unfiltered FDOM measurements underestimated filtered FDOM concentrations by up to ∼60% at particle concentrations typical of many riverine systems during hydrologic events. Together, laboratory and in situ data provide insights into the timing and magnitude of changes in DOM quantity and quality during storm events in an agricultural watershed, and indicate the need for sample filtration in systems with moderate to high suspended sediment loads.

  16. High-frequency sampling of the 1984 spring bloom within the Mid-Atlantic Bight: Synoptic shipboard, aircraft, and in situ perspectives of the SEEP—I experiment

    NASA Astrophysics Data System (ADS)

    Walsh, John J.; Wirick, Creighton D.; Pietrafesa, Leonard J.; Whitledge, Terry E.; Hoge, Frank E.; Swift, Robert N.

    1988-05-01

    Moorings of current meters, thermistors, transmissometers, and fluorometers on the Mid-Atlantic shelf, south of Long Island, suggest a seaward export of perhaps 0.20 mg Chl m -3 day -1 at depths of 75-81 m, between the 80- and 120-m isobaths during February-April 1984. Using a C/Chl ratio of 45/1, such a horizontal loss of algal carbon over the lower third of the water column would be 19-67% of the March-April 1984 primary production within the overlying euphotic zone. This possible physical carbon loss is similar to daily grazing losses to zooplankton of 32-40% of the algal fixation of carbon. Metabolic demands of the benthos could be met by just the estimated fecal pellet flux, without direct consumption of the remaining algal carbon. Similarly bacterioplankton metabolism could be fueled by excretory release of dissolved organic matter during photosynthesis, rather than by consumption of particulate carbon. Sediment traps tethered 10 and 70 m off the bottom at the 120-m isobath caught as much as 0.10-0.16 g C m -2 during March-April 1984. This presumed vertical flux is about one-third to one-half of the horizontal flux of 0.30 g C m -2 day -1 estimated over the lower 33 m of the water column at the 100-m isobath. These estimates suggest that ˜50% of the carbon export at the shelf-break might be derived from the adjacent overlying water column, with the remainder from lateral injections of near-bottom particles originating on the inner shelf.

  17. PhotoSpec - Ground-based Remote Sensing of Solar-Induced Chlorophyll Fluorescence

    NASA Astrophysics Data System (ADS)

    Grossmann, K.; Frankenberg, C.; Seibt, U.; Hurlock, S. C.; Pivovaroff, A.; Stutz, J.

    2015-12-01

    Solar-Induced Chlorophyll Fluorescence (SIF) emitted from vegetation can be used as a constraint for photosynthetic activity and is now observable on a global scale from space. However, many issues on a leaf-to-canopy scale remain poorly understood, such as influences on the SIF signal of environmental conditions, water stress, or radiation. Here, we report on the development and characterization of a novel ground-based spectrometer system for measuring SIF from natural ecosystems (http://www.kiss.caltech.edu/study/photosynthesis/technology.html). The instrumental set-up, requirements, and measurement technique are based on decades of experience using Differential Optical Absorption Spectroscopy (DOAS), an established method to measure atmospheric trace gases. The instrument consists of three thermally stabilized commercial spectrometers that are linked to a 2D scanning telescope unit via optical fiber bundles. The spectrometers cover an SIF retrieval wavelength range at high spectral resolution (670 - 780 nm, 0.1 nm FWHM), but also provide moderate resolution spectra (400 - 800 nm, 1.5 nm FWHM) in order to retrieve vegetation indices and the photochemical reflectance index (PRI). In addition to the instrumental set-up, we will show initial results of test and field measurements with the new instrument that examine the diurnal cycle of the SIF signal of different California native and non-native plants and its correlation with CO2 fluxes. Observations were made under different environmental conditions, variable water and nutrient stress, and with different viewing geometries. We also used concurrent observations by a photosynthetically active radiation (PAR) sensor and a portable chlorophyll fluorometer (PAM) to link the SIF signal to plant metabolism and carbon cycling under a range of environmental conditions.

  18. DNA as Sensors and Imaging Agents for Metal Ions

    PubMed Central

    Xiang, Yu

    2014-01-01

    Increasing interests in detecting metal ions in many chemical and biomedical fields have created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal ion-dependent DNAzymes and metal ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attaching these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detections. These sensors are highly sensitive (with detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of “dipstick tests”, portable fluorometers, computer-readable discs, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state, and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal ion sensing and imaging in many fields of applications. PMID:24359450

  19. Influence of the Amazon River discharge on the biogeography of phytoplankton communities in the western tropical north Atlantic

    NASA Astrophysics Data System (ADS)

    Goes, Joaquim I.; Gomes, Helga do Rosario; Chekalyuk, Alexander M.; Carpenter, Edward J.; Montoya, Joseph P.; Coles, Victoria J.; Yager, Patricia L.; Berelson, William M.; Capone, Douglas G.; Foster, Rachel A.; Steinberg, Deborah K.; Subramaniam, Ajit; Hafez, Mark A.

    2014-01-01

    An Advanced Laser Fluorometer (ALF) capable of discriminating several phytoplankton pigment types was utilized in conjunction with microscopic data to map the distribution of phytoplankton communities in the Amazon River plume in May-June-2010, when discharge from the river was at its peak. Cluster analysis and Non-metric Multi-Dimensional Scaling (NMDS) helped distinguish three distinct biological communities that separated largely on the basis of salinity gradients across the plume. These three communities included an "estuarine type" comprised of a high biomass mixed population of diatoms, cryptophytes and green-water Synechococcus spp. located upstream of the plume, a "mesohaline type" made up largely of communities of Diatom-Diazotroph Associations (DDAs) and located in the northwestern region of the plume and an "oceanic type" in the oligotrophic waters outside of the plume made up of Trichodesmium and Synechococcus spp. Although salinity appeared to have a substantial influence on the distribution of different phytoplankton groups, ALF and microscopic measurements examined in the context of the hydro-chemical environment of the river plume, helped establish that the phytoplankton community structure and distribution were strongly controlled by inorganic nitrate plus nitrite (NO3 + NO2) availability whose concentrations were low throughout the plume. Towards the southern, low-salinity region of the plume, NO3 + NO2 supplied by the onshore flow of subsurface (∼80 m depth) water, ensured the continuous sustenance of the mixed phytoplankton bloom. The large drawdown of SiO3 and PO4 associated with this "estuarine type" mixed bloom at a magnitude comparable to that observed for DDAs in the mesohaline waters, leads us to contend that, diatoms, cryptophytes and Synechococcus spp., fueled by the offshore influx of nutrients also play an important role in the cycling of nutrients in the Amazon River plume.

  20. Water intrusions and particle signatures in the Black Sea: a Biogeochemical-Argo float investigation

    NASA Astrophysics Data System (ADS)

    Stanev, Emil Vassilev; Grayek, Sebastian; Claustre, Hervé; Schmechtig, Chaterine; Poteau, Antoine

    2017-07-01

    Continuous observations during 3 years with a vertical resolution of 1 dbar from two Bio-Argo floats in the Black Sea that were equipped with oxygen optodes, chlorophyll fluorometers, and backscattering sensors are analyzed. The particle backscattering coefficient, b bp provides a proxy for the concentration of suspended particles. The observations clearly identify thermal and b bp intrusions down to 700-800 m in the Bosporus inflow area. In this area, b bp is more than five times larger than elsewhere, which could indicate bacterial abundance and possible biological involvement in the precipitation of Mn-containing particles. The b bp anomalies become much shallower than the temperature anomalies with increasing distance to the east of the strait. Their maxima are located between the onset of the suboxic zone and the upper part of the anoxic layer. Unlike well-known intrusions that are caused by inflow, open ocean intrusions are shallower and often characterized by multiple layers of backscatter maxima with thicknesses of only 15-20 m. The ratio between backscattering coefficients measured at two wavelengths, which gives a proxy for particle size, shows that the relative amount of larger size particles in the anoxic layer increases with depth. The particle concentrations and their size distribution display different vertical variability, which indicates the complex transformation of biological matter. The lower concentration of particles and lower chlorophyll-a during the extremely warm 2016 reveals an overall positive correlation between the two properties. The trends in the particle backscattering coefficient in the suboxic zone during 2013-2016 could indirectly reveal a biogeochemical response to temperature changes.

  1. Preparation and characterization of SiO₂:Sm³⁺ nanotube arrays with 1.06 μm laser antireflective property

    SciTech Connect

    Tan, Wei-min; Huang, Ning; Wang, Li-jun; Song, Tian-shun; Lu, Chun-hua; Wang, Liu-fang; Zhang, Jun-zhi

    2013-05-01

    SiO₂: Sm³⁺ nanotube arrays with excellent antireflective property at 1.06 μm were synthesized by a template-assisted sol–gel process. The molecular structure, morphology and optical properties of the fabricated SiO₂:Sm³⁺ nanotube arrays were investigated by a Fourier transform infrared spectroscope (FTIR), a Scanning electron microscope (SEM), and a spectro-fluorometer, respectively. The experimental results demonstrate that the SiO₂:Sm³⁺ nanotube arrays were formed via the AAO membrane during the sol–gel process. The remarkable antireflective characteristic of about 0.166% at 1.06 μm was attributed to the drastic decrease of effective refraction index which enhances the matching effect between air and substrate. As well as the absorption performance of Sm³⁺ at 1.06 μm which consumes the energies of incident light. - Graphical abstract: Directional aligned SiO₂:Sm³⁺ nanotube arrays were synthesized in AAO template by sol–gel process, and the antiflective performance of arrays is prominent comparing to the blank AAO template. Highlights: • SiO₂:Sm³⁺ nanotube arrays are synthesized by a template-assisted sol–gel process. • SiO₂:Sm³⁺ nanotube arrays have remarkable antireflective properties at 1.06 μm. • The subwavelength structure results in a decrease of effective refraction index. • The absorption performance of Sm³⁺ at 1.06 μm consume the energies of incident light.

  2. Water intrusions and particle signatures in the Black Sea: a Biogeochemical-Argo float investigation

    NASA Astrophysics Data System (ADS)

    Stanev, Emil Vassilev; Grayek, Sebastian; Claustre, Hervé; Schmechtig, Chaterine; Poteau, Antoine

    2017-09-01

    Continuous observations during 3 years with a vertical resolution of 1 dbar from two Bio-Argo floats in the Black Sea that were equipped with oxygen optodes, chlorophyll fluorometers, and backscattering sensors are analyzed. The particle backscattering coefficient, b bp provides a proxy for the concentration of suspended particles. The observations clearly identify thermal and b bp intrusions down to 700-800 m in the Bosporus inflow area. In this area, b bp is more than five times larger than elsewhere, which could indicate bacterial abundance and possible biological involvement in the precipitation of Mn-containing particles. The b bp anomalies become much shallower than the temperature anomalies with increasing distance to the east of the strait. Their maxima are located between the onset of the suboxic zone and the upper part of the anoxic layer. Unlike well-known intrusions that are caused by inflow, open ocean intrusions are shallower and often characterized by multiple layers of backscatter maxima with thicknesses of only 15-20 m. The ratio between backscattering coefficients measured at two wavelengths, which gives a proxy for particle size, shows that the relative amount of larger size particles in the anoxic layer increases with depth. The particle concentrations and their size distribution display different vertical variability, which indicates the complex transformation of biological matter. The lower concentration of particles and lower chlorophyll-a during the extremely warm 2016 reveals an overall positive correlation between the two properties. The trends in the particle backscattering coefficient in the suboxic zone during 2013-2016 could indirectly reveal a biogeochemical response to temperature changes.

  3. Self-etching adhesives increase collagenolytic activity in radicular dentin.

    PubMed

    Tay, Franklin R; Pashley, David H; Loushine, Robert J; Weller, R Norman; Monticelli, Francesca; Osorio, Raquel

    2006-09-01

    Endogenous matrix metalloproteinases (MMPs) release from crown dentin and their activation results in degradation of hybrid layers created by dentin adhesives. This study tested the hypothesis that instrumented intraradicular dentin possesses latent collagenolytic activity that is activated by mild self-etching adhesives. Root dentin shavings were produced from 50 cleaned and shaped, saline-irrigated root canals using Gates Glidden drills and rinsed with sodium azide to prevent bacterial growth. Dried dentin powder aliquots were treated with two clinically-relevant MMP inhibitors, 2% chlorhexidine for 10 minutes and 17% EDTA for 1 minute. Additional dentin powder was mixed with Clearfil Liner Bond 2V or Clearfil Tri-S Bond for 1 minute followed by extracting the adhesives with acetone. Dentin powder was also treated with 2% chlorhexidine for 10 minutes before or after adhesive application. Collagenolytic activities of the nine groups were assayed with a fluorometer in 96-well plates, by recording the changes in fluorescence before and after addition of fluorescein-labeled type I collagen. Epoxy resin-embedded powders were examined with TEM for the extent of demineralization. Instrumented, mineralized intraradicular dentin possessed low but detectable collagenolytic activity that was inhibited by chlorhexidine (p < 0.001) and EDTA (p < 0.001). Both adhesives partially demineralized the dentin powder and activated latent MMPs, with 14- to 15-fold increases in collagenolytic activities (p < 0.001) that were significantly (p < 0.001) but incompletely inactivated after 10 min application of chlorhexidine. Mild self-etching adhesives activate latent MMPs without denaturing these enzymes, and may adversely affect the longevity of bonded root canal fillings and posts.

  4. Field and controlled environment measurements show strong seasonal acclimation in photosynthesis and respiration potential in boreal Scots pine.

    PubMed

    Kolari, Pasi; Chan, Tommy; Porcar-Castell, Albert; Bäck, Jaana; Nikinmaa, Eero; Juurola, Eija

    2014-01-01

    Understanding the seasonality of photosynthesis in boreal evergreen trees and its control by the environment requires separation of the instantaneous and slow responses, as well as the dynamics of light reactions, carbon reactions, and respiration. We determined the seasonality of photosynthetic light response and respiration parameters of Scots pine (Pinus sylvestris L.) in the field in southern Finland and in controlled laboratory conditions. CO2 exchange and chlorophyll fluorescence were measured in the field using a continuously operated automated chamber setup and fluorescence monitoring systems. We also carried out monthly measurements of photosynthetic light, CO2 and temperature responses in standard conditions with a portable IRGA and fluorometer instrument. The field and response measurements indicated strong seasonal variability in the state of the photosynthetic machinery with a deep downregulation during winter. Despite the downregulation, the photosynthetic machinery retained a significant capacity during winter, which was not visible in the field measurements. Light-saturated photosynthesis (P sat) and the initial slope of the photosynthetic light response (α) obtained in standard conditions were up to 20% of their respective summertime values. Respiration also showed seasonal acclimation with peak values of respiration in standard temperature in spring and decline in autumn. Spring recovery of all photosynthetic parameters could be predicted with temperature history. On the other hand, the operating quantum yield of photosystem II and the initial slope of photosynthetic light response stayed almost at the summertime level until late autumn while at the same time P sat decreased following the prevailing temperature. Comparison of photosynthetic parameters with the environmental drivers suggests that light and minimum temperature are also decisive factors in the seasonal acclimation of photosynthesis in boreal evergreen trees.

  5. Evaluation of algal biofilms on indium tin oxide (ITO) for use in biophotovoltaic platforms based on photosynthetic performance.

    PubMed

    Ng, Fong-Lee; Phang, Siew-Moi; Periasamy, Vengadesh; Yunus, Kamran; Fisher, Adrian C

    2014-01-01

    In photosynthesis, a very small amount of the solar energy absorbed is transformed into chemical energy, while the rest is wasted as heat and fluorescence. This excess energy can be harvested through biophotovoltaic platforms to generate electrical energy. In this study, algal biofilms formed on ITO anodes were investigated for use in the algal biophotovoltaic platforms. Sixteen algal strains, comprising local isolates and two diatoms obtained from the Culture Collection of Marine Phytoplankton (CCMP), USA, were screened and eight were selected based on the growth rate, biochemical composition and photosynthesis performance using suspension cultures. Differences in biofilm formation between the eight algal strains as well as their rapid light curve (RLC) generated using a pulse amplitude modulation (PAM) fluorometer, were examined. The RLC provides detailed information on the saturation characteristics of electron transport and overall photosynthetic performance of the algae. Four algal strains, belonging to the Cyanophyta (Cyanobacteria) Synechococcus elongatus (UMACC 105), Spirulina platensis. (UMACC 159) and the Chlorophyta Chlorella vulgaris (UMACC 051), and Chlorella sp. (UMACC 313) were finally selected for investigation using biophotovoltaic platforms. Based on power output per Chl-a content, the algae can be ranked as follows: Synechococcus elongatus (UMACC 105) (6.38×10(-5) Wm(-2)/µgChl-a)>Chlorella vulgaris UMACC 051 (2.24×10(-5) Wm(-2)/µgChl-a)>Chlorella sp.(UMACC 313) (1.43×10(-5) Wm(-2)/µgChl-a)>Spirulina platensis (UMACC 159) (4.90×10(-6) Wm(-2)/µgChl-a). Our study showed that local algal strains have potential for use in biophotovoltaic platforms due to their high photosynthetic performance, ability to produce biofilm and generation of electrical power.

  6. Reduction of UV-B radiation causes an enhancement of photoinhibition in high light stressed aquatic plants from New Zealand lakes.

    PubMed

    Hanelt, Dieter; Hawes, Ian; Rae, Rowena

    2006-08-01

    Anthropogenic stratospheric ozone depletion causes an increase of UV-B radiation impinging on the earth surface, which is a threat to plants not adapted to higher UV-B irradiances. Investigations were undertaken with aquatic plants from New Zealand, where UV-irradiances are naturally higher due to the southern latitude, to compare with former results of polar species. The experiments reported in this study were undertaken with plants collected from different lakes of the South Island, with different UV transparencies. Photoinhibition was induced under controlled conditions using a sun simulator, which mimicked the natural underwater radiation spectrum. Photosynthetic activity during high light stress, and during recovery in dim light, was determined in vivo by measuring fluorescence changes, using a PAM fluorometer device. A comparison of different species showed that the extent to which UV causes an additional decrease of photosynthetic performance during high light stress varies according to the depth of growth and UV transparency of the water body. This observation fits with previous studies. However, a new finding was that some species were even more strongly inhibited when UV-B was filtered out of the simulated sun spectrum, indicating a supporting effect of the short UVR wavelength range against photoinhibition. These results were also confirmed by field experiments under natural radiation conditions. Thus, UV-B does not solely cause negative effects on photosynthesis, but it may even support recovery processes in aquatic plants adapted to a high UV-radiation environment. The latter is in contrast to earlier studies, in which UV-B radiation was considered causing only harmful effects on photosynthesis of aquatic plants.

  7. C-MORE Science Kits: Putting Technology in the Hands of K-12 Teachers and Students

    NASA Astrophysics Data System (ADS)

    Achilles, K.; Weersing, K.; Daniels, C.; Puniwai, N.; Matsuzaki, J.; Bruno, B. C.

    2008-12-01

    The Center for Microbial Oceanography: Research and Education (C-MORE) is a NSF Science and Technology Center based at the University of Hawaii. The C-MORE education and outreach program offers a variety of resources and professional development opportunities for science educators, including online resources, participation in oceanography research cruises, teacher-training workshops, mini-grants to incorporate microbial oceanography-related content and activities into their classroom and, most recently, C- MORE science kits. C-MORE science kits provide hands-on classroom, field, and laboratory activities related to microbial oceanography for K-12 students. Each kit comes with complete materials and instructions, and is available free of charge to Hawaii's public school teachers. Several kits are available nationwide. C-MORE science kits cover a range of topics and technologies and are targeted at various grade levels. Here is a sampling of some available kits: 1) Marine Murder Mystery: The Case of the Missing Zooxanthellae. Students learn about the effect of climate change and other environmental threats on coral reef destruction through a murder-mystery experience. Participants also learn how to use DNA to identify a suspect. Grades levels: 3-8. 2) Statistical sampling. Students learn basic statistics through an exercise in random sampling, with applications to microbial oceanography. The laptops provided with this kit enable students to enter, analyze, and graph their data using EXCEL. Grades levels: 6-12. 3) Chlorophyll Lab. A research-quality fluorometer is used to measure the chlorophyll content in marine and freshwater systems. This enables students to compare biomass concentrations in samples collected from various locations. Grades levels: 9-12. 4) Conductivity-Temperature-Depth (CTD). Students predict how certain variables (e.g., temperature, pressure, chlorophyll, oxygen) vary with depth. A CTD, attached to a laptop computer, is deployed into deep water

  8. Fluorescence spectroscopy for wastewater monitoring: A review.

    PubMed

    Carstea, Elfrida M; Bridgeman, John; Baker, Andy; Reynolds, Darren M

    2016-05-15

    Wastewater quality is usually assessed using physical, chemical and microbiological tests, which are not suitable for online monitoring, provide unreliable results, or use hazardous chemicals. Hence, there is an urgent need to find a rapid and effective method for the evaluation of water quality in natural and engineered systems and for providing an early warning of pollution events. Fluorescence spectroscopy has been shown to be a valuable technique to characterize and monitor wastewater in surface waters for tracking sources of pollution, and in treatment works for process control and optimization. This paper reviews the current progress in applying fluorescence to assess wastewater quality. Studies have shown that, in general, wastewater presents higher fluorescence intensity compared to natural waters for the components associated with peak T (living and dead cellular material and their exudates) and peak C (microbially reprocessed organic matter). Furthermore, peak T fluorescence is significantly reduced after the biological treatment process and peak C is almost completely removed after the chlorination and reverse osmosis stages. Thus, simple fluorometers with appropriate wavelength selectivity, particularly for peaks T and C could be used for online monitoring in wastewater treatment works. This review also shows that care should be taken in any attempt to identify wastewater pollution sources due to potential overlapping fluorophores. Correlations between fluorescence intensity and water quality parameters such as biochemical oxygen demand (BOD) and total organic carbon (TOC) have been developed and dilution of samples, typically up to ×10, has been shown to be useful to limit inner filter effect. It has been concluded that the following research gaps need to be filled: lack of studies on the on-line application of fluorescence spectroscopy in wastewater treatment works and lack of data processing tools suitable for rapid correction and extraction of

  9. In situ fluorescence measurements of protein-, humic- and HAP-like materials in the Northwestern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Tedetti, Marc; Bachet, Caroline; Germain, Chloé; Ferretto, Nicolas; Bhairy, Nagib; Guigue, Catherine; Besson, Florent; Beguery, Laurent; Goutx, Madeleine

    2015-04-01

    Understanding the biogeochemical functioning of the ocean requires high frequency measurements of dissolved organic matter (DOM) descriptors. For 10 years, the technological developments of fluorescence sensors try to cover this need. In this context, our laboratory developed the MiniFluo-UV sensor, a prototype of miniaturized submersible fluorometer for the detection of aromatic compounds that fluoresce in the UV spectral domain. The qualification of the sensor consisted in measurements of drift, linearity, repeatability, sensitivity to light, temperature and pressure, and detection limits of phenanthrene (HAP) and tryptophan (aromatic amino acid) in standard solutions. Measurements were also conducted in crude oil water soluble fractions (WSFs). The MiniFluo-UV sensor was then deployed in two distinct areas of the Northwestern Mediterranean Sea: 1) in the Gulf of Lion during the continuous monitoring of the surface water layer (DEWEX cruise, winter and spring 2013) and 2) in the Bay of Marseilles, heavily impacted by urban activities, where the sensor was mounted onto the SeaExplorer underwater glider and onto a CTD vertical profiler (July-December 2014). These platforms were also equipped with a humic-like fluorescence sensor and other sensors for hydrological and biogeochemical parameters (T, S, Chla, oxygen, turbidity). The patterns of fluorescence signatures enabled to distinguish interesting distributions of DOM in relation with hydrological features and spring biological production in the Gulf of Lion, and showed the accumulation of contaminants in marine areas under anthropogenic pressure. This work was conducted within the framework of the ANR-09-ECOT-009-01 "IBISCUS" in collaboration with ALSEAMAR-ALCEN (Aix-en-Provence) and MicroModule (Brest) companies. It is relevant to WP5 NEXOS objectives. The SACEUP team of the DEWEX-MERMEX experiment is warmly acknowledged.

  10. Tracer gauge: an automated dye dilution gauging system for ice-affected streams

    USGS Publications Warehouse

    Clow, D.W.; Fleming, A.C.

    2008-01-01

    In-stream flow protection programs require accurate, real-time streamflow data to aid in the protection of aquatic ecosystems during winter base flow periods. In cold regions, however, winter streamflow often can only be estimated because in-channel ice causes variable backwater conditions and alters the stage-discharge relation. In this study, an automated dye dilution gauging system, a tracer gauge, was developed for measuring discharge in ice-affected streams. Rhodamine WT is injected into the stream at a constant rate, and downstream concentrations are measured with a submersible fluorometer. Data loggers control system operations, monitor key variables, and perform discharge calculations. Comparison of discharge from the tracer gauge and from a Cipoletti weir during periods of extensive ice cover indicated that the root-mean-square error of the tracer gauge was 0.029 m3 s−1, or 6.3% of average discharge for the study period. The tracer gauge system can provide much more accurate data than is currently available for streams that are strongly ice affected and, thus, could substantially improve management of in-stream flow protection programs during winter in cold regions. Care must be taken, however, to test for the validity of key assumptions, including complete mixing and conservative behavior of dye, no changes in storage, and no gains or losses of water to or from the stream along the study reach. These assumptions may be tested by measuring flow-weighted dye concentrations across the stream, performing dye mass balance analyses, and evaluating breakthrough curve behavior.

  11. Effects of barbiturates on human platelet aggregation differ depending on their chemical structures.

    PubMed

    Sato, Masami; Hirakata, Hideo; Ikeda, Masahiro; Fukuda, Kazuhiko

    2003-08-01

    The effects of barbiturates on human platelet function are not fully understood. Since we have already revealed the effects and mechanisms of thiopental, thiamylal, and pentobarbital in platelets, the present study attempted to elucidate (i) the effects of other barbiturates on human platelet aggregation, (ii) the underlying mechanisms, and (iii) the structure-function relationship of barbiturates in platelets. Barbiturates, including amobarbital, butalbital, secobarbital, barbital, phenobarbital, metharbital, and primidone, were examined. Human platelet aggregation induced by adenosine diphosphate (ADP), epinephrine, and (+)-9,11-epithia-11,12-methano-thromboxane A2 (STA2), a thromboxane A2 analog, was measured using an 8-channel light-transmission aggregometer. The cytosolic free calcium concentration ([Ca2+]i) was measured by fluorometer using fura-2 loaded platelets. Inositol 1,4,5-trisphosphate (IP3) formation induced by STA2 was determined by a commercially available IP3 assay kit. Amobarbital, butalbital, and secobarbital suppressed ADP-, epinephrine- and STA2-induced platelet aggregation and the STA2-induced [Ca2+]i increase, even when Ca2+ influx was blocked by Ni2+. However, they did not affect STA2-induced IP3 formation. Barbital, phenobarbital, metharbital, and primidone (up to 1 mM) had no effect on ADP- and epinephrine-induced platelet aggregation. Thus, we conclude that amobarbital, butalbital, and secobarbital inhibit platelet aggregation by suppressing [Ca2+]i increase without affecting IP3 formation. However, these antiaggregatory effects may not have clinical importance, since the barbiturate concentrations used were higher than clinically relevant ones. The other tested barbiturates had no effects on platelet aggregation. The data indicate that the effects of barbiturates on platelet aggregation differ depending on their chemical structures.

  12. Standardization of DNA extraction from sand flies: Application to genotyping by next generation sequencing.

    PubMed

    Casaril, Aline Etelvina; de Oliveira, Liliane Prado; Alonso, Diego Peres; de Oliveira, Everton Falcão; Gomes Barrios, Suellem Petilim; de Oliveira Moura Infran, Jucelei; Fernandes, Wagner de Souza; Oshiro, Elisa Teruya; Ferreira, Alda Maria Teixeira; Ribolla, Paulo Eduardo Martins; de Oliveira, Alessandra Gutierrez

    2017-06-01

    Standardization of the methods for extraction of DNA from sand flies is essential for obtaining high efficiency during subsequent molecular analyses, such as the new sequencing methods. Information obtained using these methods may contribute substantially to taxonomic, evolutionary, and eco-epidemiological studies. The aim of the present study was to standardize and compare two methods for the extraction of genomic DNA from sand flies for obtaining DNA in sufficient quantities for next-generation sequencing. Sand flies were collected from the municipalities of Campo Grande, Camapuã, Corumbá and Miranda, state of Mato Grosso do Sul, Brazil. Three protocols using a silica column-based commercial kit (ReliaPrep™ Blood gDNA Miniprep System kit, Promega(®)), and three protocols based on the classical phenol-chloroform extraction method (Uliana et al., 1991), were compared with respect to the yield and quality of the extracted DNA. DNA was quantified using a Qubit 2.0 fluorometer. The presence of sand fly DNA was confirmed by PCR amplification of the IVS6 region (constitutive gene), followed by electrophoresis on a 1.5% agarose gel. A total of 144 male specimens were analyzed, 72 per method. Significant differences were observed between the two methods tested. Protocols 2 and 3 of phenol-chloroform extraction presented significantly better performance than all commercial kit extraction protocols tested. For phenol-chloroform extraction, protocol 3 presented significantly better performance than protocols 1 and 2. The IVS6 region was detected in 70 of 72 (97.22%) samples extracted with phenol, including all samples for protocols 2 and 3. This is the first study on the standardization of methods for the extraction of DNA from sand flies for application to next-generation sequencing, which is a promising tool for entomological and molecular studies of sand flies. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Response of lower trophic level production to long-term climate change in the southeastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Jin, Meibing; Deal, Clara; Wang, Jia; McRoy, C. Peter

    2009-04-01

    The Bering Sea ecosystem has undergone profound changes in response to climate regime shifts in the past decades. Here, lower trophic level production is assessed with a vertically one-dimensional (1-D) coupled ice-ocean ecosystem model, which was applied to data collected by a National Oceanic and Atmospheric Administration (NOAA)/Pacific Marine Environmental Laboratory (PMEL) mooring from 1995 to 2005. The physical model is forced by sea surface winds, heat and salt fluxes, tides, and sea ice. The biological model includes coupled pelagic and ice algae components. Model results are validated with daily mooring temperature, fluorometer, and daily Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll data. Two distinct ocean conditions and phytoplankton bloom patterns are related to the Pacific Decadal Oscillation (PDO) Index regimes: warmer temperature and later warm-water phytoplankton species bloom in PDO > 1 year; colder temperature and earlier cold-water phytoplankton species bloom in PDO < -1 year. Productivity of different phytoplankton species changed dramatically after the 1976 climate shift, but the total annual net primary production (NPP) remained flat over the past four decades under similar nutrient regulation. Climate shift also affected the vertical distribution of lower trophic level production and energy flow to the upper ocean pelagic ecosystem or the benthic community. A long-term PDO regime shift occurred in 1976, and a short-term PDO reversal occurred in 1998. Phytoplankton biomass responded promptly to both short- and long-term climate changes. Zooplankton biomass responded more to the long-term than to the short-term climate shift. The model results captured observed trends of zooplankton abundance changes from the 1990s to 2004.

  14. Overview of Hydrographic Data From the GEOTRACES EPZT Cruise

    NASA Astrophysics Data System (ADS)

    German, C. R.; Swift, J. H.; Moffett, J. W.; Cutter, G. A.; Becker, S. M.; Johnson, M. C.; Miller, M. T.; Palomares, R.

    2014-12-01

    During the US GEOTRACES East Pacific Zonal Transect (EPZT) cruise extensive use was made of the hydrographic data collected by the SIO Shipboard Technical Support team aboard ship to select suitable depths for water column sampling at all stations. Across the eastern half of the section, starting from the Peru Margin and spanning the Oxygen Minimum Zone (OMZ), attention was paid to not only the standard hydrographic sensors but also the fluorometer and dissolved oxygen sensors interfaced to the CTD, for example to select depths associated with the chlorophyll maximum in the uppermost water column and also the underlying low oxygen waters which formed a primary focus for sampling to investigate redox-cycling within the OMZ. In the western half of the section, attention turned toward the extensive hydrothermal plume which was first intercepted directly above the southern East Pacific Rise ridge axis near 15°S. There, the depth and intensity of the hydrothermal plume was revealed by a combination of the standard sensor suite interfaced to the CTD/rosette, augmented with an Oxygen Reduction Potential (ORP) probe provided by NOAA-PMEL and a SeaPoint optical back scatter sensor provided by WHOI. Thorough on-board salinity, dissolved oxygen, and nutrient analyses provided key data for CTD calibration, quality control and hydrographic interpretation including clear evidence for dissolved phosphate scavenging in the near-field hydrothermal plume. We will compare the EPZT CTD/hydrographic data with WOCE-era (1991-1994) sections including zonal section P21, which parallels the new transect, and crossovers with WOCE meridional sections P16, P17, P18, and P19.

  15. Comparison of photosynthesis and fluorescent parameters between Dendrobium officinale and Dendrobium loddigesii

    PubMed Central

    Sun, Zhi-Rong; Zhu, Nan-Nan; Cheng, Li-Li; Yang, Chun-Ning

    2015-01-01

    Objective: To investigate the photosynthesis and fluorescent parameters between Dendrobium officinale and Dendrobium loddigesii, based on which to provide helpful information for the artificial cultivation of these cultivars. Methods: Seeds were placed on the MS medium supplemented with 0.2 mg/L NAA, 2% (w/v) sucrose, 15% (v/v) potato extracts and powered agar (pH 5.8). Two months after germination, seedlings (n = 10) were transferred onto rooting medium containing MS medium supplemented with 0.5 mg/L NAA, 3% (w/v) sucrose, 20% (v/v) potato extracts and 1‰ (w/v) activated carbon (pH 5.8) in a glass bottle (6.5 cm in diameter and 9.5 cm in height) with a white transparent plastic cap. Chlorophyll content was determined using the UV-Vis spectrophotometric method. In addition, rates of oxygen evolution and uptake were measured. The chlorophyll fluorescence was determined at room temperature using PAM 2000 chlorophyll fluorometer (Heinz Walz GmbH, Germany). Results: From month 5 to month 10, the overall contents of both chlorophyll a and chlorophyll b were higher in D. loddigesii compared with those in D. officinale. No statistical differences were observed in the apparent photosynthetic rate (APR) between D. loddigesii and D. officinale. No statistical difference was noticed in the Fo, Fm and Fv between D. loddigesii and D. officinale (P > 0.05). Significant increase was noticed in the oxygen consuming in PSI in month-8 and month-10 compared with that of month-6 in D. loddigesii. Nevertheless, in the D. officinale, the oxygen consuming in PSI in month-6 was remarkably increased with those of month-8 and month-10, respectively. Conclusions: The photosynthesis and fluorescence parameters varied in the seedling of D. loddigesii and D. officinale. Such information could contribute to the artificial cultivation of these cultivars. PMID:26550239

  16. Performance of Fast Repetition Rate fluorometry based estimates of primary productivity in coastal waters

    NASA Astrophysics Data System (ADS)

    Robinson, C.; Suggett, D. J.; Cherukuru, N.; Ralph, P. J.; Doblin, M. A.

    2014-11-01

    Capturing the variability of primary productivity in highly dynamic coastal ecosystems remains a major challenge to marine scientists. To test the suitability of Fast Repetition Rate fluorometry (FRRf) for rapid assessment of primary productivity in estuarine and coastal locations, we conducted a series of paired analyses estimating 14C carbon fixation and primary productivity from electron transport rates with a Fast Repetition Rate fluorometer MkII, from waters on the Australian east coast. Samples were collected from two locations with contrasting optical properties and we compared the relative magnitude of photosynthetic traits, such as the maximum rate of photosynthesis (Pmax), light utilisation efficiency (α) and minimum saturating irradiance (EK) estimated using both methods. In the case of FRRf, we applied recent algorithm developments that enabled electron transport rates to be determined free from the need for assumed constants, as in most previous studies. Differences in the concentration and relative proportion of optically active substances at the two locations were evident in the contrasting attenuation of PAR (400-700 nm), blue (431 nm), green (531 nm) and red (669 nm) wavelengths. FRRF-derived estimates of photosynthetic parameters were positively correlated with independent estimates of 14C carbon fixation (Pmax: n = 19, R2 = 0.66; α: n = 21, R2 = 0.77; EK: n = 19, R2 = 0.45; all p < 0.05), however primary productivity was frequently underestimated by the FRRf method. Up to 81% of the variation in the relationship between FRRf and 14C estimates was explained by the presence of pico-cyanobacteria and chlorophyll-a biomass, and the proportion of photoprotective pigments, that appeared to be linked to turbidity. We discuss the potential importance of cyanobacteria in influencing the underestimations of FRRf productivity and steps to overcome this potential limitation.

  17. Allelopathic potential and ecotoxicity evaluation of gallic and nonanoic acids to prevent cyanobacterial growth in lentic systems: A preliminary mesocosm study.

    PubMed

    Techer, Didier; Fontaine, Pascal; Personne, Aline; Viot, Sandrine; Thomas, Marielle

    2016-03-15

    The increase in anthropogenic nutrient loading affecting many freshwater ecosystems combined with global warming may lead to cyanobacterial blooms on an increasingly frequent basis. Among the various physicochemical and biological methods which have been proposed to rapidly control blue-green algae growth, the use of plant-derived substances such as allelochemicals has gained great interest as an environment-friendly approach. The primary aim of this work was to evaluate the efficiency of gallic and nonanoic acid application to preemptively inhibit cyanobacterial growth in lentic hydrosystems. In order to address the process feasibility under realistic exposure scenarios, thirteen outdoor freshwater mesocosms (unit volume: 3m(3)) were designed, each containing phytoplankton (including local blue-green algae species) and various non-target organisms from higher trophic levels (Physa, Lymnaea, Gammarus, and Scardinius erythrophthalmus). After an 8-week mesocosm stabilization period, a full factorial design based on the presence/absence of gallic acid (GA) and nonanoic acid (NA) (including a control group) was implemented into the exposure tanks. Regular monitoring of major phytoplankton taxa was conducted during a 28-day experiment using an on-line fluorometer. The main results suggested that gallic acid was more efficient than nonanoic acid at limiting cyanobacterial growth at concentrations as low as 1 mg L(-1). Successive gallic acid applications (at 1, 2 and 4 mg L(-1)) at the early stages of cyanobacterial growth did not allow the complete elimination of blue-green algae from the mesocosms. However, the specificity of the allelopathic effect of gallic acid towards cyanobacteria was compatible with the maintenance of a primary productivity in the treated tanks as indicated by the photoautotrophic growth of other algal taxa. Finally, no biomarker induction signal could be reported in non-target species. Further gallic acid application trials in lentic systems such

  18. Continuing and New Measurements at the Abyssal ALOHA Cabled Observatory

    NASA Astrophysics Data System (ADS)

    Howe, B. M.; Potemra, J. T.; Butler, R.; Santiago-Mandujano, F.; Lukas, R.; Duennebier, F. K.; Karl, D. M.; Aucan, J.

    2016-02-01

    The ALOHA Cabled Observatory (ACO) is a general purpose "node" providing power, communications and timing connectivity for science use at Station ALOHA 100 km north of Oahu. Included are a suite of basic sensors making core measurements, some local and some sensing the water column. At 4728 m deep, it is the deepest scientific outpost on the planet with power and Internet. Importantly, Station ALOHA is the field site of the NSF-funded Hawaii Ocean Time-series (HOT) program that has investigated temporal dynamics in biology, physics, and chemistry since 1988, at a site that is representative of roughly 70% of the world ocean, sampling the ocean from top to bottom to monitor and study changes on scales of months to decades. The co-located Woods Hole mooring (WHOTS) provides meteorological and upper ocean physical data. The CMORE (Center for Microbial Oceanography Research and Education) and SCOPE (Simons Collaboration on Ocean Processes and Ecology) programs address their respective science topics at ALOHA. Together these programs provide a truly unique means for observing the ocean across all disciplines and regimes (deep sea, near surface, etc.). ACO has been operating in the abyss since June 2011, collecting temperature, salinity, velocity, acoustic, and video data (see for instance the abstract by Lukas et al., Spatial Analysis of Abyssal Temperature Variations Observed from the ALOHA Cabled Observatory and WHOTS Moorings). Using the University of Hawaii remotely operated vehicle ROV Lu`ukai, a basic sensor package was recently installed equipped with a Paroscientific nano-resolution pressure sensor, a WetLabs fluorometer/turbidity sensor, and a Seabird CTDO2 instrument. These data will be presented and described.

  19. Effects of bisphenol A on growth, photosynthesis and chlorophyll fluorescence in above-ground organs of soybean seedlings.

    PubMed

    Qiu, Zhiyong; Wang, Lihong; Zhou, Qing

    2013-01-01

    Bisphenol A (BPA) is a representatively endocrine disruptor, which shows a highly toxic effect on life system. Its potential toxicity on plants that are the primary producers in earth's ecosystem is not well documented. Here, the effects of BPA on the growth, photosynthesis, content of chlorophyll (Chl), initial fluorescence (F(0)), maximal photochemical efficiency (F(v)/F(m)), effective quantum yield of photosystem II (Φ(PSII)) and photosynthetic electron transport rate (ETR) in soybean seedlings were investigated by using gas exchange measurement system and chlorophyll fluorometer to understand the toxic effect of BPA on plants. It was found that when soybean seedlings were treated with BPA at the low concentration (1.5 mg L(-1)), the growth indices (the plant height, fresh and dry weights of stems, fresh and dry weights of leaves, leaf area) were increased obviously compared with those of the control, which was not related with the photosynthesis, the content of Chl and the chlorophyll fluorescence. When soybean seedlings were treated with BPA at the high concentrations (7.0, 12.0, 17.2 and 50.0 mg L(-1)), the growth indices, net photosynthetic rate, the content of chlorophyll, F(v)/F(m), Φ(PSII), ETR were decreased, while F(0) was increased, compared with those of the control. Obviously, BPA at the high concentrations showed the toxic effect on soybean seedlings. The results from correlation analysis indicated that the inhibition in the growth of soybean seedlings treated with BPA was related to the decrease in photosynthesis because of the decrease in the content of chlorophyll and the change in chlorophyll fluorescence. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Generation of cell lines for drug discovery through random activation of gene expression: application to the human histamine H3 receptor.

    PubMed

    Song, J; Doucette, C; Hanniford, D; Hunady, K; Wang, N; Sherf, B; Harrington, J J; Brunden, K R; Stricker-Krongrad, A

    2005-06-01

    Target-based high-throughput screening (HTS) plays an integral role in drug discovery. The implementation of HTS assays generally requires high expression levels of the target protein, and this is typically accomplished using recombinant cDNA methodologies. However, the isolated gene sequences to many drug targets have intellectual property claims that restrict the ability to implement drug discovery programs. The present study describes the pharmacological characterization of the human histamine H3 receptor that was expressed using random activation of gene expression (RAGE), a technology that over-expresses proteins by up-regulating endogenous genes rather than introducing cDNA expression vectors into the cell. Saturation binding analysis using [125I]iodoproxyfan and RAGE-H3 membranes revealed a single class of binding sites with a K(D) value of 0.77 nM and a B(max) equal to 756 fmol/mg of protein. Competition binding studies showed that the rank order of potency for H3 agonists was N(alpha)-methylhistamine approximately (R)-alpha- methylhistamine > histamine and that the rank order of potency for H3 antagonists was clobenpropit > iodophenpropit > thioperamide. The same rank order of potency for H3 agonists and antagonists was observed in the functional assays as in the binding assays. The Fluorometic Imaging Plate Reader assays in RAGE-H3 cells gave high Z' values for agonist and antagonist screening, respectively. These results reveal that the human H3 receptor expressed with the RAGE technology is pharmacologically comparable to that expressed through recombinant methods. Moreover, the level of expression of the H3 receptor in the RAGE-H3 cells is suitable for HTS and secondary assays.

  1. New treatment of dry eye: the effect of calcium ointment through eyelid skin delivery

    PubMed Central

    Tsubota, K.; Monden, Y.; Yagi, Y.; Goto, E.; Shimmura, S.

    1999-01-01

    AIM—To demonstrate the efficacy of a petrolatum based calcium ointment applied to the lower lid skin in the management of dry eye.
METHODS—In a controlled double masked study, the effects of water free petrolatum ointment containing calcium carbonate (10% w/w) on tear functional factors and ocular surface vital staining in dry eye patients were observed. Petrolatum without calcium carbonate served as control. Patients were instructed to place ointment to the lower lid skin twice a day. Evaluation of subjective complaints, fluorescein and rose bengal staining patterns, blink rate, tear evaporation and tear break up time (BUT) were performed before and 3 months after treatment. In order to demonstrate the movement of petrolatum from the skin to the tear film, petrolatum containing 1% sodium fluorescein was placed on the lower lid of four healthy volunteers, and the concentration of fluorescein in the tear film was followed up to 6 hours using an anterior fluorometer.
RESULTS—Subjective symptoms significantly improved in both the calcium group (p=0.001) and control (p=0.012), while only the calcium group demonstrated a significant improvement in fluorescein (p=0.043), rose bengal (p=0.021) scores, and blink rate (p=0.004). Tear evaporation also significantly decreased in both the calcium group (p=0.0004) and control (0.043). BUT did not improve in either group.
CONCLUSION—Petrolatum based calcium ointment significantly improved symptoms, tear dynamics, and ocular surface staining in dry eye patients. However, some of the therapeutic effects may be due to lipids in the petrolatum vehicle. Petrolatum applied to the lower lid skin is an effective drug delivery system for slowly releasing drugs to the ocular surface.

 PMID:10381659

  2. Multiplex loop-mediated isothermal amplification (M-LAMP) assay for the detection of influenza A/H1, A/H3 and influenza B can provide a specimen-to-result diagnosis in 40 min with single genome copy sensitivity.

    PubMed

    Mahony, James; Chong, Sylvia; Bulir, David; Ruyter, Alexandra; Mwawasi, Ken; Waltho, Daniel

    2013-09-01

    Rapid isothermal amplification methods have recently been introduced and they offer significant advantages over PCR. To develop a rapid and sensitive M-LAMP assay for the detection of influenza A (H1 and H3) and B that does not require RNA extraction. We designed six primers targeting the matrix genes of influenza H1 and H3 and the NS1 gene of influenza B and developed a M-LAMP assay using a commercially available Master Mix and a real time fluorometer (Genie II, Optigene, UK) that displays real time amplification, time to positivity and amplicon annealing temperature (Tm). M-LAMP was evaluated against PCR by testing 202 nasopharyngeal (NP) specimens. Optimized M-LAMP was rapid with a mean amplification time of 12 min (compared with 90-120 min for PCR), had an analytical sensitivity of 1 genome equivalent (ge), and could distinguish influenza A including subtypes A/H1 and A/H3 from influenza B by Tm. M-LAMP detected 26/28 influenza A/H1, 27/27 influenza A/H3 and 39/39 influenza B specimens and had a combined sensitivity and specificity for detecting influenza (A and B) of 97.9% (92/94) and 100% (108/108), respectively. The rapid amplification time of LAMP coupled with a novel 10-min specimen preparation procedure consisting of vortexing and heating in M-Swab diluent (Copan Italia) provided a rapid result. M-LAMP had excellent sensitivity and specificity for detecting influenza A and B in NP specimens and when used together with a rapid specimen processing method provided a specimen-to-result diagnosis in 30 min. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Sinking towards destiny: High throughput measurement of phytoplankton sinking rates through time-resolved fluorescence plate spectroscopy.

    PubMed

    Bannon, Catherine C; Campbell, Douglas A

    2017-01-01

    Diatoms are marine primary producers that sink in part due to the density of their silica frustules. Sinking of these phytoplankters is crucial for both the biological pump that sequesters carbon to the deep ocean and for the life strategy of the organism. Sinking rates have been previously measured through settling columns, or with fluorimeters or video microscopy arranged perpendicularly to the direction of sinking. These side-view techniques require large volumes of culture, specialized equipment and are difficult to scale up to multiple simultaneous measures for screening. We established a method for parallel, large scale analysis of multiple phytoplankton sinking rates through top-view monitoring of chlorophyll a fluorescence in microtitre well plates. We verified the method through experimental analysis of known factors that influence sinking rates, including exponential versus stationary growth phase in species of different cell sizes; Thalassiosira pseudonana CCMP1335, chain-forming Skeletonema marinoi RO5A and Coscinodiscus radiatus CCMP312. We fit decay curves to an algebraic transform of the decrease in fluorescence signal as cells sank away from the fluorometer detector, and then used minimal mechanistic assumptions to extract a sinking rate (m d-1) using an RStudio script, SinkWORX. We thereby detected significant differences in sinking rates as larger diatom cells sank faster than smaller cells, and cultures in stationary phase sank faster than those in exponential phase. Our sinking rate estimates accord well with literature values from previously established methods. This well plate-based method can operate as a high throughput integrative phenotypic screen for factors that influence sinking rates including macromolecular allocations, nutrient availability or uptake rates, chain-length or cell size, degree of silification and progression through growth stages. Alternately the approach can be used to phenomically screen libraries of mutants.

  4. Dual-wavelength excitation to reduce background fluorescence for fluorescence spectroscopic quantitation of erythrocyte zinc protoporphyrin-IX and protoporphyrin-IX from whole blood and oral mucosa

    NASA Astrophysics Data System (ADS)

    Hennig, Georg; Vogeser, Michael; Holdt, Lesca M.; Homann, Christian; Großmann, Michael; Stepp, Herbert; Gruber, Christian; Erdogan, Ilknur; Hasmüller, Stephan; Hasbargen, Uwe; Brittenham, Gary M.

    2014-02-01

    Erythrocyte zinc protoporphyrin-IX (ZnPP) and protoporphyrin-IX (PPIX) accumulate in a variety of disorders that restrict or disrupt the biosynthesis of heme, including iron deficiency and various porphyrias. We describe a reagent-free spectroscopic method based on dual-wavelength excitation that can measure simultaneously both ZnPP and PPIX fluorescence from unwashed whole blood while virtually eliminating background fluorescence. We further aim to quantify ZnPP and PPIX non-invasively from the intact oral mucosa using dual-wavelength excitation to reduce the strong tissue background fluorescence while retaining the faint porphyrin fluorescence signal originating from erythrocytes. Fluorescence spectroscopic measurements were made on 35 diluted EDTA blood samples using a custom front-face fluorometer. The difference spectrum between fluorescence at 425 nm and 407 nm excitation effectively eliminated background autofluorescence while retaining the characteristic porphyrin peaks. These peaks were evaluated quantitatively and the results compared to a reference HPLC-kit method. A modified instrument using a single 1000 μm fiber for light delivery and detection was used to record fluorescence spectra from oral mucosa. For blood measurements, the ZnPP and PPIX fluorescence intensities from the difference spectra correlated well with the reference method (ZnPP: Spearman's rho rs = 0.943, p < 0.0001; PPIX: rs = 0.959, p < 0.0001). In difference spectra from oral mucosa, background fluorescence was reduced significantly, while porphyrin signals remained observable. The dual-wavelength excitation method evaluates quantitatively the ZnPP/heme and PPIX/heme ratios from unwashed whole blood, simplifying clinical laboratory measurements. The difference technique reduces the background fluorescence from measurements on oral mucosa, allowing for future non-invasive quantitation of erythrocyte ZnPP and PPIX.

  5. In Situ Stoichiometry in a Large River: Continuous Measurement of Doc, NO3 and PO4 in the Sacramento River

    NASA Astrophysics Data System (ADS)

    Downing, B. D.; Pellerin, B. A.; Bergamaschi, B. A.; Saraceno, J.

    2011-12-01

    Studying controls on geochemical processes in rivers and streams is difficult because concentration and composition often changes rapidly in response to physical and biological forcings. Understanding biogeochemical dynamics in rivers will improve current understanding of the role of watershed sources to carbon cycling, river and stream ecology, and loads to estuaries and oceans. Continuous measurements of dissolved organic carbon (DOC), nitrate (NO3-) and soluble reactive phosphate (SRP) concentrations are now possible, along with some information about DOC composition. In situ sensors designed to measure these constituents provide high frequency, real-time data that can elucidate hydrologic and biogeochemical controls which are difficult to detect using more traditional sampling approaches. Here we present a coupled approach, using in situ optical instrumentation with discharge measurements to provide quantitative estimates of constituent loads to investigate C, NO3- and SRP sources and processing in the Sacramento River, CA, USA. Continuous measurement of DOC concentration was conducted by use of a miniature in situ fluorometer (Turner Designs Cyclops) designed to measure chromophoric dissolved organic matter fluorescence (FDOM) over the course of an entire year. Nitrate was measured concurrently using a Satlantic SUNA and phosphate was measured using a WETLabs model Cycle-P instrument for a two week period in July 2011. Continuous measurement from these instruments paired with continuous measurement of physical water quality variables such as temperature, pH, specific conductance, dissolved oxygen, and turbidity, were used to investigate physical and chemical dynamics of DOC, NO3-, SRP over varying time scales. Deploying these instruments at pre-existing USGS discharge gages allowed for calculation of instantaneous and integrated constituent fluxes, as well as filling in gaps in our understanding biogeochemical processes and transport. Results from the study

  6. A rapid solid-phase extraction fluorometric method for thiamine and riboflavin in salmonid eggs

    USGS Publications Warehouse

    Zajicek, James L.; Tillitt, Donald E.; Brown, Scott B.; Brown, Lisa R.; Honeyfield, Dale C.; Fitzsimons, John D.

    2005-01-01

    fluorescent thiochromes; and an ultraviolet-visible-wavelength-filter fluorometer for the measurements. ?? Copyright by the American Fisheries Society 2005.

  7. Magnetic focusing immunosensor for the detection of Salmonella typhimurium in foods

    NASA Astrophysics Data System (ADS)

    Pivarnik, Philip E.; Cao, He; Letcher, Stephen V.; Pierson, Arthur H.; Rand, Arthur G.

    1999-01-01

    From 1988 through 1992 Salmonellosis accounted for 27% of the total reported foodborne disease outbreaks and 57% of the outbreaks in which the pathogen was identified. The prevalence of Salmonellosis and the new requirements to monitor the organism as a marker in pathogen reduction programs will drive the need for rapid, on-site testing. A compact fiber optic fluorometer using a red diode laser as an excitation source and fiber probes for analyte detection has been constructed and used to measure Salmonella. The organisms were isolated with anti-Salmonella magnetic beads and were labeled with a secondary antibody conjugated to a red fluorescent dye. The response of the system was proportional to the concentration of Salmonella typhimurium from 3.2 X 105 colony forming units (CFU)/ml to 1.6 X 107 CFU/ml. The system was developed to utilize a fiber-optic magnetic focusing problem that attracted the magnetic microspheres to the surface of a sample chamber directly in front of the excitation and emission fibers. The signal obtained from a homogenous suspension of fluorescent magnetic microspheres was 9 to 10 picowatts. After focusing, the signal from the fluorescent labeled magnetic microspheres increased to 200 picowatts, approximately 20 times greater than the homogeneous suspension. The magnetic focusing assay detected 1.59 X 105 colony forming units/ml of Salmonella typhimurium cultured in growth media. The process of magnetic focusing in front of the fibers has the potential to reduce the background fluorescence from unbound secondary antibodies, eliminating several rinsing steps, resulting in a simple rapid assay.

  8. Bloom Chasing With a Wave Glider: The MAGI (Mesoscale Features Aggregates Interaction) Project in the North Pacific

    NASA Astrophysics Data System (ADS)

    Wilson, C.; Villareal, T. A.; Anderson, E.

    2015-12-01

    Satellite ocean color data over the past decade has revealed the existence of large phytoplankton blooms in the North Pacific Ocean - specifically in the region NE of Hawai´I near 30°N. These blooms cover thousands of km2, persist for weeks or longer, and are often dominated by nitrogen-fixing diatom symbioses. These events have proven difficult to study outside of the time series station ALOHA at Hawai´i. The limited data indicates that the 30°N blooms are longer-lived, larger, and occur at a greater temperature range than the blooms that develop closer to Hawai´i. In the NE Pacific, at least some of these blooms occur at or near the subtropical front, a salinity-defined temperature compensated frontal zone that has a number of fronts imbedded in it. Here we will report on the results from the MAGI (Mesoscale features Aggregates Interaction) project. In this project, we deployed a Liquid Robotics SV2 Wave Glider® in June, 2015 for a multiple (up to 6) month mission to sample these features and assist in characterizing the bloom dynamics of this region. The Wave Gliders are the first unmanned autonomous marine robots to use only the ocean's wave energy for propulsion. The gliders are navigated remotely allowing a dynamic route through the keying of unique waypoints. Waypoints can be changed to sample features as they develop in the near-real time satellite imagery. The wave glider named Honey Badger is equipped with a CTD, two C3 fluorometers (one with an anti-biofouling coating applied), a Turner Designs PhytoFlash, meteorology and wave sensors, a downward facing camera, a Vengmar passive acoustic monitor, and a towed LISST-Holo.

  9. Solid Phase Biosensors for Arsenic or Cadmium Composed of A trans Factor and cis Element Complex

    PubMed Central

    Siddiki, Mohammad Shohel Rana; Kawakami, Yasunari; Ueda, Shunsaku; Maeda, Isamu

    2011-01-01

    The presence of toxic metals in drinking water has hazardous effects on human health. This study was conducted to develop GFP-based-metal-binding biosensors for on-site assay of toxic metal ions. GFP-tagged ArsR and CadC proteins bound to a cis element, and lost the capability of binding to it in their As- and Cd-binding conformational states, respectively. Water samples containing toxic metals were incubated on a complex of GFP-tagged ArsR or CadC and cis element which was immobilized on a solid surface. Metal concentrations were quantified with fluorescence intensity of the metal-binding states released from the cis element. Fluorescence intensity obtained with the assay significantly increased with increasing concentrations of toxic metals. Detection limits of 1 μg/L for Cd(II) and 5 μg/L for As(III) in purified water and 10 µg/L for Cd(II) and As(III) in tap water and bottled mineral water were achieved by measurement with a battery-powered portable fluorometer after 15-min and 30-min incubation, respectively. A complex of freeze dried GFP-tagged ArsR or CadC binding to cis element was stable at 4 °C and responded to 5 μg/L As(III) or Cd(II). The solid phase biosensors are sensitive, less time-consuming, portable, and could offer a protocol for on-site evaluation of the toxic metals in drinking water. PMID:22346629

  10. The Quasi-Static Self Quenching of Trp-X and X-Trp Dipeptides in Water: Ultrafast Fluorescence Decay

    PubMed Central

    Xu, Jianhua; Knutson, Jay R.

    2012-01-01

    Time-resolved fluorescence decay profiles of N-acetyl-L-tryptophan-amide (NATA) and tryptophan (Trp) dipeptides of the form Trp-X and X-Trp, where X is another aminoacyl residue, have been investigated using an ultraviolet upconversion spectrophoto fluorometer with time resolution better than 350 fs, together with a time correlated single photon counting apparatus on the 100ps to 20ns time scale. We analyzed the set of fluorescence decay profiles at multiple wavelengths using the global analysis technique. Nanosecond fluorescence transients for Trp dipeptides all show multiexponential decay, while NATA exhibits a monoexponential decay near 3 ns independent of pH. In the first 100 ps, a time constant for the water “bulk relaxation” around Trp, NATA and Trp dipeptides is seen near 1-2 ps, with an associated preexponential amplitude that is positive or negative depending on emission wavelength, as expected for a population-conserving spectral shift. The initial brightness (sub-ps) we measure for all these dipeptides is less than that of NATA, implying even faster (<200fs) intra-molecular (quasi) static quenching occurs within them. A new, third, ultrafast decay, bearing an exponential time constant of 20-30 ps with positive amplitude, has been found in many of these dipeptides. We believe it verifies our previous predictions of dipeptide QSSQ (“quasi static self quenching”) –the loss of quantum yield to sub-100ps decay process (Chen et al., Biochemistry, 1991, 30, 5184). Most important, this term is found in proteins as well (J.A.C.S., 2006, 128, 1214; Biophysical Journal 2008, 94, 546; 2009, 96, 46a), suggesting an ultrafast quenching mechanism must be common to both. PMID:19708715

  11. Water flow influences oxygen transport and photosynthetic efficiency in corals

    NASA Astrophysics Data System (ADS)

    Finelli, Christopher M.; Helmuth, Brian S. T.; Pentcheff, N. Dean; Wethey, David S.

    2006-03-01

    Recent studies indicate that the incidence and persistence of damage from coral reef bleaching are often highest in areas of restricted water motion, and that resistance to and recovery from bleaching is increased by enhanced water motion. We examined the hypothesis that water motion increases the efflux of oxygen from coral tissue thereby reducing oxidative stress on the photosynthetic apparatus of endosymbiotic zooxanthellae. We experimentally exposed colonies of Montastrea annularis and Agaricia agaricites to manipulations of water flow, light intensity, and oxygen concentration in the field using a novel mini-flume. We measured photosynthetic efficiency using a pulse amplitude modulated fluorometer to test the short-term response of corals to our manipulations. Under normal oxygen concentrations, A. agaricites showed a significant 8% increase in photosynthetic efficiency from 0.238 (± 0.032) in still water to 0.256 (± 0.037) in 15 cm s-1 flow, while M. annularis exhibited no detectable change. Under high-ambient oxygen concentrations, the observed effect of flow on A. agaricites was reversed: photosynthetic efficiencies showed a significant 11% decrease from 0.236 (± 0.056) in still water to 0.211 (± 0.048) in 15 cm s-1 flow. These results support the hypothesis that water motion helps to remove oxygen from coral tissues during periods of maximal photosynthesis. Flow mitigation of oxidative stress may at least partially explain the increased incidence and severity of coral bleaching in low flow areas and observations of enhanced recovery in high-flow areas.

  12. Dissipation of triclopyr herbicide applied in Lake Minnetonka, MN concurrently with Rhodamine WT dye.

    PubMed

    Fox, Alison M; Haller, William T; Getsinger, Kurt D; Petty, David G

    2002-07-01

    Fluorescent dye was applied concurrently with triclopyr in two 6.5-ha treatment plots in Lake Minnetonka, MN for data collection to support full aquatic registration of this herbicide. The herbicide and dye mixture was applied by airboat to Phelps Bay with weighted, trailing hoses to maximize uniform distribution of these materials in the water column. A surface application was made to the Carsons Bay plot to attain theoretical triclopyr and dye concentrations of 2500 and 10 micrograms litre-1, respectively. Water samples collected at various times following application showed very little movement of the herbicide and dye out of the Carsons Bay plot. Triclopyr residues moved to a greater extent out of the Phelps Bay plot. The dye was easily tracked in real-time using field fluorometers, which allowed new sampling stations to be established to monitor this movement. Dye concentrations were strongly correlated to herbicide concentrations (r2 = 0.97 in both plots) but were less predictive of the triclopyr metabolite 3,5,6-trichloropyridinol (TCP; r2 = 0.82 in Phelps and r2 = 0.73 in Carsons), probably due to its differential metabolism and degradation. The inert dye can be used to compare the dissipation of herbicide residues by dilution versus microbial or other breakdown processes. Vertical sampling of dye in the water column showed that surface applications of aquatic herbicides can delay uniform mixing in the water column by several days. Although the dye aided the tracking of residues outside the treatment areas, predetermined sampling times and stations were still needed if very low concentrations of herbicide were to be detected at times and stations where the dye had been diluted below its limit of detection.

  13. Automated integrative high-throughput phenotyping of plant shoots: a case study of the cold-tolerance of pea (Pisum sativum L.).

    PubMed

    Humplík, Jan F; Lazár, Dušan; Fürst, Tomáš; Husičková, Alexandra; Hýbl, Miroslav; Spíchal, Lukáš

    2015-01-01

    Recently emerging approaches to high-throughput plant phenotyping have discovered their importance as tools in unravelling the complex questions of plant growth, development and response to the environment, both in basic and applied science. High-throughput methods have been also used to study plant responses to various types of biotic and abiotic stresses (drought, heat, salinity, nutrient-starving, UV light) but only rarely to cold tolerance. We present here an experimental procedure of integrative high-throughput in-house phenotyping of plant shoots employing automated simultaneous analyses of shoot biomass and photosystem II efficiency to study the cold tolerance of pea (Pisum sativum L.). For this purpose, we developed new software for automatic RGB image analysis, evaluated various parameters of chlorophyll fluorescence obtained from kinetic chlorophyll fluorescence imaging, and performed an experiment in which the growth and photosynthetic activity of two different pea cultivars were followed during cold acclimation. The data obtained from the automated RGB imaging were validated through correlation of pixel based shoot area with measurement of the shoot fresh weight. Further, data obtained from automated chlorophyll fluorescence imaging analysis were compared with chlorophyll fluorescence parameters measured by a non-imaging chlorophyll fluorometer. In both cases, high correlation was obtained, confirming the reliability of the procedure described. This study of the response of two pea cultivars to cold stress confirmed that our procedure may have important application, not only for selection of cold-sensitive/tolerant varieties of pea, but also for studies of plant cold-response strategies in general. The approach, provides a very broad tool for the morphological and physiological selection of parameters which correspond to shoot growth and the efficiency of photosystem II, and is thus applicable in studies of various plant species and crops.

  14. Biological dosimetry after H2O2/L-histidine treatment

    NASA Astrophysics Data System (ADS)

    Hausmann, Michael; Lentfer, Heiko; Wolf, Dietmar; Bauer, Eckhard; Aldinger, Klaus; Greulich, Karl-Otto; Cremer, Christoph G.

    1998-01-01

    In biological dosimetry after radiation or chemical exposure, it has been well established to estimate exposure doses from the relative rate of aberrant chromosomes, especially dicentric chromosomes in a given number of cells. For this purpose, dose-efficiency curves depending on laboratory parameters (e.g. preparation technique, analysis procedure etc.) have to be measured under standard conditions. For statistical reasons, a high number of chromosomes or cells, respectively, has to be evaluated. For a Chinese hamster cell line (CO60) as a typical model system in mutation research, a dose efficiency relation after H2O2/L-histidine treatment of the cells was determined using the Heidelberg slit-scan flow fluorometer. This technique has the advantage that several thousand chromosomes can be automatically analyzed in a very short time. As expected, for low doses of H2O2/L-histidine exposure, a nearly linear dependence of the relative number of dicentric chromosomes to the concentration of H2O2 was obtained. In order to correlate the relative number of dicentric chromosomes to the relative number of double strand breaks, the cells were analyzed by the technique of the neutral comet assay. The dose dependent `tail moment' obtained from the comet assay also showed a linear behavior. This confirmed the results obtained by slit-scan flow fluorometry. Furthermore, the linear dependence of the dose efficiency curve was well compatible to results obtained by visual counting by means of a fluorescence microscope. In this case chromosome 1 of the Chinese hamster cell line DON was specifically labelled by fluorescence in situ hybridization.

  15. Biological dosimetry after H2O2/L-histidine treatment

    NASA Astrophysics Data System (ADS)

    Hausmann, Michael; Lentfer, Heiko; Wolf, Dietmar; Bauer, Eckhard; Aldinger, Klaus; Greulich, Karl O.; Cremer, Christoph

    1997-12-01

    In biological dosimetry after radiation or chemical exposure, it has been well established to estimate exposure doses from the relative rate of aberrant chromosomes, especially dicentric chromosomes in a given number of cells. For this purpose, dose-efficiency curves depending on laboratory parameters (e.g. preparation technique, analysis procedure etc.) have to be measured under standard conditions. For statistical reasons, a high number of chromosomes or cells, respectively, has to be evaluated. For a Chinese hamster cell line (CO60) as a typical model system in mutation research, a dose efficiency relation after H2O2/L-histidine treatment of the cells was determined using the Heidelberg slit-scan flow fluorometer. This technique has the advantage that several thousand chromosomes can be automatically analyzed in a very short time. As expected, for low doses of H2O2/L-histidine exposure, a nearly linear dependence of the relative number of dicentric chromosomes to the concentration of H2O2 was obtained. In order to correlate the relative number of dicentric chromosomes to the relative number of double strand breaks, the cells were analyzed by the technique of the neutral comet assay. The dose dependent `tail moment' obtained from the comet assay also showed a linear behavior. This confirmed the results obtained by slit-scan flow fluorometry. Furthermore, the linear dependence of the dose efficiency curve was well compatible to results obtained by visual counting by means of a fluorescence microscope. In this case chromosome 1 of the Chinese hamster cell line DON was specifically labelled by fluorescence in situ hybridization.

  16. Physiology and cryosensitivity of coral endosymbiotic algae (Symbiodinium).

    PubMed

    Hagedorn, M; Carter, V L; Leong, J C; Kleinhans, F W

    2010-04-01

    Coral throughout the world are under threat. To save coral via cryopreservation methods, the Symbiodinium algae that live within many coral cells must also be considered. Coral juvenile must often take up these important cells from their surrounding water and when adult coral bleach, they lose their endosymbiotic algae and will die if they are not regained. The focus of this paper was to understand some of the cryo-physiology of the endosymbiotic algae, Symbiodinium, living within three species of Hawaiian coral, Fungia scutaria, Porites compressa and Pocillopora damicornis in Kaneohe Bay, Hawaii. Although cryopreservation of algae is common, the successful cryopreservation of these important coral endosymbionts is not common, and these species are often maintained in live serial cultures within stock centers worldwide. Freshly-extracted Symbiodinium were exposed to cryobiologically appropriate physiological stresses and their viability assessed with a Pulse Amplitude Fluorometer. Stresses included sensitivity to chilling temperatures, osmotic stress, and toxic effects of various concentrations and types of cryoprotectants (i.e., dimethyl sulfoxide, propylene glycol, glycerol and methanol). To determine the water and cryoprotectant permeabilities of Symbiodinium, uptake of radio-labeled glycerol and heavy water (D(2)O) were measured. The three different Symbiodinium subtypes studied demonstrated remarkable similarities in their morphology, sensitivity to cryoprotectants and permeability characteristics; however, they differed greatly in their sensitivity to hypo- and hyposmotic challenges and sensitivity to chilling, suggesting that standard slow freezing cryopreservation may not work well for all Symbiodinium. An appendix describes our H(2)O:D(2)O water exchange experiments and compares the diffusionally determined permeability with the two parameter model osmotic permeability. Published by Elsevier Inc.

  17. ALOHA Cabled Observatory: Continuing lessons and results

    NASA Astrophysics Data System (ADS)

    Howe, B. M.; Lukas, R.

    2012-12-01

    Since June 2011, the ALOHA Cabled Observatory (ACO) is providing 1 kW power, 100 Mbs network communications and PPS timing to a seafloor node and instruments at 4728 m water depth 100 km north of Oahu. Station ALOHA is the field site of the Hawaii Ocean Time-series (HOT) program that has investigated physical and biogeochemical variability of the water column near-monthly since 1988. The abyssal near bottom acoustic Doppler profiler data are showing stronger than expected internal tide flows and turbulence 20-80 m above bottom. In this oligotrophic environment, the video camera has detected significant biological activity. Acoustic data collected on two hydrophones clearly show very high call density of baleen whales during September-May and sperm whale choruses spread throughout the year. Recent Navy exercises provided examples of anthropogenic sounds. We are also monitoring in real time an acoustic "heartbeat" signal from the nearby HOT Profiler mooring (M. Alford et al.). ACO operation over the last year continues to provide valuable lessons. Several failures occurred at or during deployment, including two ground faults that have isolated two CTDs, a fluorometer, and an acoustic modem from the system. Two independent LED light systems failed after 4 and 6 weeks. Most recently, the pressure sensor has failed perhaps due to loss of vacuum in the quartz crystal chamber. The one remaining conductivity/temperature sensor is episodically, but strongly, affected by thermal plume signatures from the nearby power supply. Understanding the reasons for these failures and limitations will be necessary to improve the methodologies for sustained long-term abyssal measurements. This will be well worth the effort, as suggested by the surprisingly rich video, ADCP, and acoustic data sets.

  18. Extrapolation of band-limited frequency data using an iterative Hilbert-transform method and its application for Fourier-transform phase-modulation fluorometry

    NASA Astrophysics Data System (ADS)

    Iwata, Tetsuo; Shibata, Hironobu; Araki, Tsutomu

    2007-01-01

    We propose a new band-extrapolation method using an iterative Hilbert-transform procedure, which is applicable for band-limited complex-frequency data obtained from a Fourier-transform phase-modulation fluorometer (FT-PMF). Without the band limitation, the real and the imaginary parts of the complex-frequency data obtained from the FT-PMF form a Hilbert-transform pair because of causality. However, the Hilbert-transform relation cannot actually hold because of the inevitable band limitation in the instrument. In order to alleviate this problem, we propose the band-extrapolation method. First, the real part of the complex-frequency data is Hilbert-transformed and the partial frequency data inside the band are replaced by the imaginary ones actually measured while those outside are kept as they are. Next, the corrected imaginary-frequency data are inverse-Hilbert-transformed again and the real-frequency data inside the band are replaced by those measured while those outside are kept. Such a procedure is iterated until changes in shapes of respective frequency waveforms are sufficiently small. Finally, we can obtain a desired time-domain waveform by the inverse Fourier transform of the pair of the extrapolated complex-frequency data. Numerical simulations showed that the proposed method was valid. A good agreement between two fluorescence decay waveforms of fluo-5N in calcium ion buffer, one obtained from the proposed method and the other obtained from the conventional time-correlated single-photon counting method, showed that the proposed method was useful.

  19. Apparent PS II absorption cross-section and estimation of mean PAR in optically thin and dense suspensions of Chlorella.

    PubMed

    Klughammer, Christof; Schreiber, Ulrich

    2015-01-01

    Theoretical prediction of effective mean PAR in optically dense samples is complicated by various optical effects, including light scattering and reflections. Direct information on the mean rate of photon absorption by PS II is provided by the kinetics of the fluorescence rise induced upon onset of strong actinic illumination (O-I1 rise). A recently introduced kinetic multi-color PAM fluorometer was applied to study the relationship between initial slope and cell density in the relatively simple model system of suspensions of Chlorella. Use of a curve fitting routine was made which was originally developed for assessment of the wavelength-dependent absorption cross-section of PS II, σ II(λ), in dilute suspensions. The model underlying analysis of the O-I1 rise kinetics is outlined and data on the relationship between fitted values of σ II(λ) and PAR in dilute samples are presented. With increasing cell density, lowering of apparent cross-section, <σ>(λ), with respect to σ II(λ), relates to a decrease of effective mean PAR, (λ), relative to incident PAR(λ). When ML and AL are applied in the same direction, the decline of <σ>(λ)/σ II(λ) with increasing optical density is less steep than that of the theoretically predicted (λ)/PAR(λ). It approaches a value of 0.5 when the same colors of ML and AL are used, in agreement with theory. These observations open the way for estimating mean PAR in optically dense samples via measurements of <σ>(λ)/σ II(λ)).

  20. Caracterisation of anthropogenic contribution to the coastal fluorescent organic matter

    NASA Astrophysics Data System (ADS)

    El Nahhal, Ibrahim; Nouhi, Ayoub; Mounier, Stéphane

    2015-04-01

    It is known that most of the coastal fluorescent organic matter is of a terrestrial origin (Parlanti, 2000; Tedetti, Guigue, & Goutx, 2010). However, the contribution of the anthropogenic organic matter to this pool is not well defined and evaluated. In this work the monitoring of little bay (Toulon Bay, France) was done in the way to determine the organic fluorescent response during a winter period. The sampling campaign consisted of different days during the month of December, 2014 ( 12th, 15th, 17th, 19th) on 21 different sampling sites for the fluorescence measurements (without any filtering of the samples) and the whole month of December for the bacterial and the turbidity measurements. Excitation Emission Matrices (EEMs) of fluorescence (from 200 to 400 nm and 220 to 420 nm excitation and emission range) were treated by parallel factor analysis (PARAFAC).The parafac analysis of the EEM datasets was conducted using PROGMEEF software in Matlab langage. On the same time that the turbidity and bacterial measurement (particularly the E.Coli concentration) were determined. The results gives in a short time range, information on the the contribution of the anthropogenic inputs to the coastal fluorescent organic matter. In addition, the effect of salinity on the photochemical degradation of the anthropogenic organic matter (especially those from wastewater treatment plants) will be studied to investigate their fate in the water end member by the way of laboratory experiments. Parlanti, E. (2000). Dissolved organic matter fluorescence spectroscopy as a tool to estimate biological activity in a coastal zone submitted to anthropogenic inputs. Organic Geochemistry, 31(12), 1765-1781. doi:10.1016/S0146-6380(00)00124-8 Tedetti, M., Guigue, C., & Goutx, M. (2010). Utilization of a submersible UV fluorometer for monitoring anthropogenic inputs in the Mediterranean coastal waters. Marine Pollution Bulletin, 60(3), 350-62. doi:10.1016/j.marpolbul.2009.10.018

  1. Geomorphic and substrate controls on spatial variability in river solute transport and biogeochemical cycling

    NASA Astrophysics Data System (ADS)

    Blaen, Phillip; Kurz, Marie; Knapp, Julia; Mendoza-Lera, Clara; Lee-Cullin, Joe; Klaar, Megan; Drummond, Jen; Jaeger, Anna; Zarnetske, Jay; Lewandowski, Joerg; Marti, Eugenia; Ward, Adam; Fleckenstein, Jan; Datry, Thibault; Larned, Scott; Krause, Stefan

    2016-04-01

    Nutrient concentrations in surface waters and groundwaters are increasing in many agricultural catchments worldwide as a result of anthropogenic activities. Increasing geomorphological heterogeneity in river channels may help to attenuate nutrient pollution by facilitating water exchange fluxes with the hyporheic zone; a site of intense microbial activity where biogeochemical transformation rates (e.g. denitrification) can be high. However, the controls on spatial variability in biogeochemical cycling, particularly at scales relevant for river managers, are not well understood. Here, we aimed to assess: 1) how differences in geomorphological heterogeneity control river solute transport and rates of biogeochemical cycling at sub-reach scales (102 m); and 2) the relative magnitude of these differences versus those relating to reach scale substrate variability (103 m). We used the reactive 'smart' tracer resazurin (Raz), a weakly fluorescent dye that transforms to highly fluorescent resorufin (Rru) under mildly reducing conditions, as a proxy to assess rates of biogeochemical cycling in a lowland river in southern England. Solute tracer tests were conducted in two reaches with contrasting substrates: one sand-dominated and the other gravel-dominated. Each reach was divided into sub-reaches that varied in geomorphic complexity (e.g. by the presence of pool-riffle sequences or the abundance of large woody debris). Slug injections of Raz and the conservative tracer fluorescein were conducted in each reach during baseflow conditions (Q ≈ 80 L/s) and breakthrough curves monitored using in-situ fluorometers. Preliminary results indicate overall Raz:Rru transformation rates in the gravel-dominated reach were more than 50% higher than those in the sand-dominated reach. However, high sub-reach variability in Raz:Rru transformation rates and conservative solute transport parameters suggests small-scale targeted management interventions to alter geomorphic heterogeneity may be

  2. Measuring and modeling multidimensional dispersion in a meandering river

    NASA Astrophysics Data System (ADS)

    Logan, B. L.; Nelson, J. M.; Runkel, R. L.; McDonald, R. R.

    2009-04-01

    As part of a study to separate and characterize the active and passive components of sturgeon larval dispersal in a large river, we made detailed measurements of the dispersion of a large pulse of Rhodamine dye injected at a single upstream point. The study occurred on the Kootenai River, USA, a 200m-wide meandering river with an unusually low gradient, 2x10-5, and an average depth of 5 m at the moderate study flow of 271 m3/s. For the first 14 river kilometers downstream from the injection site, a detailed concentration data set describing the spatial and temporal evolution of the dye pulse was obtained using GPS receivers and high-accuracy fluorometers mounted on several boats. Beyond this initial reach, the dye was predominantly well-mixed in the cross-stream direction except near the leading and trailing edges of the pulse, and only longitudinal dispersion was measured. These measurements were made at a series of 11 fixed locations for an additional 45 river kilometers downstream, at which point peak dye concentrations were near the detection limit. Even for a relatively simple channel, the data indicate that local topography and bank irregularity exert a strong influence on the distribution of dye. While most of the dye pulse was apparently well mixed in the cross-stream and vertical directions, deep pools and lateral separation zones produced complex 3-dimensional structure in the concentration field, especially at the leading edge of the dye pulse. The dispersion data show that travel times in different reaches were more variable than predicted by a simple 1-dimensional model. Comparisons of the field data with results from multidimensional computational models indicate that uncommon channel features play a disproportionately important role in determining the storage and subsequent release of constituents that are passively advected and diffused.

  3. Interannual Variability of Primary Production and Fishery in Response to Climate Changes in the Bering Sea

    NASA Astrophysics Data System (ADS)

    Jin, M.; Deal, C.; McRoy, P.

    2007-12-01

    The climate trends of reducing sea ice cover and rising temperature have profound impacts on the lower tropic level production and fishery production. The lower trophic level production from 1970 to 2005 was simulated using a vertically 1-D coupled ice-ocean ecosystem model (Jin et al., 2007) that includes 10 compartments: three phytoplankton (pelagic diatom, flagellates and ice algae), three zooplankton (copepods, large zooplankton, and microzooplankton), three nutrients (nitrate+nitrite, ammonium, silicon) and detritus. By using a turbulence closure model (Mellor, 2001), tidal mixing and its interactions with wind stirring, and thermal stratification were realistically reproduced. The 1-D model was applied to the mooring site M2 in the southeastern Bering Sea. The water depth H=74m. The model is forced by NCEP reanalysis data and sea ice concentration data from Hadley Center (monthly) before 1978 and SSM/I (daily) after 1997. Surface boundary includes wind stress, heat and salt flux. Model results are validated favorably with observations: 1) temperature, salinity, fluorometer data at 12m, 24m and 44m at NOAA/PMEL mooring from 1995-2005; 2) daily SeaWiFS chl a data (1997-2005). While the quantity of variability of the primary production did not show an increase/decrease trend in the past three decade, there exists a shift of dominant phytoplankton species coincident of the Pacific Decadal Oscillation (PDO) index. The model primary production were dominant by ice algae before the 1976/77 regime shift, and by open water species of diatom and flagellates thereafter with only occasional ice algal blooms. Fish catches in the eastern Bering Sea showed mixed reponse to the climate changes. Among the 12 dominant economic fish species, only Walleye pollock and Yellowfin sole showed significant correlations with the PDO index in certain regions.

  4. Ship-of-opportunity based phycocyanin fluorescence monitoring of the filamentous cyanobacteria bloom dynamics in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Seppälä, J.; Ylöstalo, P.; Kaitala, S.; Hällfors, S.; Raateoja, M.; Maunula, P.

    2007-07-01

    Distribution of cyanobacteria cannot be evaluated using chlorophyll a (Chl a) in vivo fluorescence, as most of their Chl a is located in non-fluorescing photosystem I. Phycobilin fluorescence, in turn, is noted as a useful tool in the detection of cyanobacterial blooms. We applied phycocyanin (PC) fluorometer in the monitoring of the filamentous cyanobacterial bloom in the Baltic Sea. For the bloom forming filamentous cyanobacteria Aphanizomenon flos-aquae and Nodularia spumigena, PC fluorescence maximum was identified using the excitation-emission fluorescence matrix. Consequently, the optical setup of our instrument was noted to be appropriate for the detection of PC, and with minor or no interference from Chl a and phycoerythrin fluorescence, respectively. During summer 2005, the instrument was installed on a ferryboat commuting between Helsinki (Finland) and Travemünde (Germany), and data were collected during 32 transects providing altogether 200 000 fluorescence records. PC in vivo fluorescence was compared with Chl ain vivo fluorescence and turbidity measured simultaneously, and with Chl a concentration and biomass of the bloom forming filamentous cyanobacteria determined from discrete water samples. PC fluorescence showed a linear relation to the biomass of the bloom forming filamentous cyanobacteria, and the other sources of PC fluorescence are considered minor in the open Baltic Sea. Estimated by PC fluorescence, cyanobacterial bloom initiated late June at the Northern Baltic Proper, rapidly extended to the central Baltic Proper and the Gulf of Finland, and peaked in the mid-July with values up to 10 mg l -1 (fresh weight). In late July, bloom vanished in most areas. During single transects, or for the whole summer, the variability in Chl a concentrations was explained more by PC fluorescence than by Chl a fluorescence. Thus, filamentous cyanobacteria dominated the overall variability in phytoplankton biomass. Consequently, we show that during the

  5. Leaf carbon assimilation and molecular phylogeny in Cattleya species (Orchidaceae).

    PubMed

    Andrade-Souza, V; Almeida, A-A F; Corrêa, R X; Costa, M A; Mielke, M S; Gomes, F P

    2009-08-11

    We examined leaf CO(2) assimilation and how it varied among species within the orchid genus Cattleya. Measurements of CO(2) assimilation and maximum quantum yield of PS II (Fv/Fm) were made for mature leaves of nine species using a portable system for photosynthesis measurement and a portable fluorometer. Leaf area was measured with an area meter, and the specific leaf mass was determined. DNA of nine Cattleya species and two species of Hadrolaelia was extracted using the CTAB protocol. Each sample was amplified and sequenced using primers for the trnL gene. The phylogenetic analyses, using neighbor-joining and maximum parsimony methods, retrieved a group that included Cattleya and Hadrolaelia species, in which the unifoliate species were separated from the bifoliates. The topologies of the two cladograms showed some similarities. However, C. guttata (bifoliate) was placed in the unifoliate clade in the neighbor-joining tree, while C. warneri (unifoliate) was not placed in this clade in the maximum parsimony tree. Most Cattleya species keep the leaf stomata closed from 6 am to 4 pm. We suggest that C. elongata, C. tigrina and C. tenuis have C(3)-crassulacean acid metabolism since they open their stomata around 12 am. The Fv/Fm values remained relatively constant during the measurements of CO(2) assimilation. The same was observed for the specific leaf mass values, although great variations were found in the leaf area values. When the species were grouped using molecular data in the neighbor-joining analysis, no relation was observed with CO(2) assimilation.

  6. Quantifying temporal and spatial variability of nearshore processes around a nearshore kelp forest rocky reef with the KFA cabled observatory

    NASA Astrophysics Data System (ADS)

    Squibb, M. E.; Martone, R. G.; Litvin, S.; Woodson, C. B.; Monismith, S. G.; Dunckley, J. F.

    2016-02-01

    Oceanographic data from the Kelp Forest Array (KFA) cabled observatory is used to determine the frequency, intensity, duration and seasonal variation of low-pH and low-DO events, and relate them to temperature and density variability associated with internal waves and upwelling. We employ standard time series analyses, to determine the frequency distributions of variance in pH, DO, and T and coherence analysis to identify frequency dependent co-variability among the three variables. Statistical analysis is used to identify the probability of a hypoxic event of given strength (e.g., DO < 4.5 mg/l17) lasting for a given duration and compare this between habitats. Joint probability distribution functions of low-pH and low-DO are computed from the data in the same way. This approach can be used to identify the likelihood of extreme events with respect to specific DO and pH thresholds of physiological relevance for species of interest in MPAs. The time scales and vertical structure of velocities, temperature, and dissolved oxygen associated with low-DO events are analyzed to determine the dominant transport mechanisms for these events and how they are tied to internal shoaling waves prevalent in the southern part of Monterey Bay. Our work in 2015 is contextualized by multi-year data sets from the three previous years which contain observations of both upwelling and non-upwelling periods. Long-term instrumentation attached to the KFA main node include a 1200 KHz ADCP, a CTD with transmissometer, oxygen optode, and fluorometer (Chla), a Satlantic SeaFET pH sensor, and a PME temperature and dissolved oxygen string (DO/T chain).

  7. [Comparison between the post-column derivatization with bromine by HPLC and the fluorometric analysis for determination of aflatoxins in medicinal herbs and plant extracts].

    PubMed

    Zhang, Xue-hui; Chen, Jian-min

    2004-12-01

    To compare the post-column derivatization technique (IAC-PCD-HPLC) for the determination of aflatoxins B1, B2, G1 and G2 and the rapid procedure with fluorometric analysis (SFB) for the determination of total aflatoxins. The method of post-column derivatization with bromine by HPLC consisted of extraction of the sample with MeOH-H2O (70:30) followed by clean-up of the extracts with immunoaffinity columns and finally, HPLC determination with fluorescence detection. Aflatoxins B1 and G1 were determined as their bromine derivatives, produced in an on-line post-column derivatization system. In SFB method, samples were ground and extracted with methanol-water (70:30). A portion of the extract was cleaned up by passage through a immunoaffinity column, One mL of purified extract was derivatized with a bromine reagent, and fluorescence of the solution was immediately quantified with a calibrated fluorometer containing a broad wavelength pulsed xenon light source. In IAC-HPLC method, the overall average recoveries for three different medicinal herbs spiked at levels of 1.3 and 2.6 ng x g(-1) of total aflatoxins ranged from 93% to 97%. The detection limit was 0. 06 microg x kg(-1) for both G2 and B2 and 0.20 microg x kg(-1) for both G1 and B1, based on a signal/noise 3:1 and the precision (within-laboratory relative standard deviation) ranged from 0.8% to 1.4%. Each of aflatoxins B1, B2, G1 and G2 in 39 kind medicinal materials were determined by IAC-PCD-HPLC, and the total aflatoxins were determined by SFB. The SFB method is not the suitable method for the determination of total aflatoxins in medicinal herbs and plant extracts.

  8. Multi-scale controls on spatial variability in river biogeochemical cycling

    NASA Astrophysics Data System (ADS)

    Blaen, Phillip; Kurz, Marie; Knapp, Julia; Mendoza-Lera, Clara; Lee-Cullin, Joe; Klaar, Megan; Drummond, Jennifer; Jaeger, Anna; Zarnetske, Jay; Lewandowski, Joerg; Marti, Eugenia; Ward, Adam; Fleckenstein, Jan; Datry, Thibault; Larned, Scott; Krause, Stefan

    2016-04-01

    Excessive nutrient concentrations are common in surface waters and groundwaters in agricultural catchments worldwide. Increasing geomorphological heterogeneity in river channels may help to attenuate nutrient pollution by facilitating water exchange fluxes with the hyporheic zone; a site of intense microbial activity where biogeochemical cycling rates can be high. However, the controls on spatial variability in biogeochemical cycling, particularly at scales relevant for river managers, are largely unknown. Here, we aimed to assess: 1) how differences in river geomorphological heterogeneity control solute transport and rates of biogeochemical cycling at sub-reach scales (102 m); and 2) the relative magnitude of these differences versus those relating to reach scale substrate variability (103 m). We used the reactive tracer resazurin (Raz), a weakly fluorescent dye that transforms to highly fluorescent resorufin (Rru) under mildly reducing conditions, as a proxy to assess rates of biogeochemical cycling in a lowland river in southern England. Solute tracer tests were conducted in two reaches with contrasting substrates: one sand-dominated and the other gravel-dominated. Each reach was divided into sub-reaches that varied in geomorphic complexity (e.g. by the presence of pool-riffle sequences or the abundance of large woody debris). Slug injections of Raz and the conservative tracer fluorescein were conducted in each reach during baseflow conditions (Q ≈ 80 L/s) and breakthrough curves monitored using in-situ fluorometers. Preliminary results indicate overall Raz:Rru transformation rates in the gravel-dominated reach were more than 50% higher than those in the sand-dominated reach. However, high sub-reach variability in Raz:Rru transformation rates and conservative solute transport parameters suggests small scale targeted management interventions to alter geomorphic heterogeneity may be effective in creating hotspots of river biogeochemical cycling and nutrient load

  9. Development and validation of a new fluorescence-based bioassay for aquatic macrophyte species.

    PubMed

    Küster, Anette; Altenburger, Rolf

    2007-02-01

    Bioassays with unicellular algae are frequently used as ecotoxicological test systems to evaluate the toxicity of contaminated environmental samples or chemicals. In contrast, aquatic macrophyte test systems are still rarely used as they are laborious to handle because species exhibit distinct ecological requirements. The aim of this study was to establish a fast and reproducible measuring system for aquatic macrophyte species to overcome those limitations for use. Thus, a newly developed pulse-amplitude modulated chlorophyll fluorometer (Imaging-PAM) was applied as an effect detection in short-term bioassays with aquatic macrophyte species. This multiwell-plate-based measuring device enables the incubation and measurement of up to 24 samples in parallel. The Imaging-PAM was used (i) to establish and validate the sensitivity of the test systems to three Photosystem II (PSII) inhibitors (atrazine, prometryn, isoproturon), (ii) to compare the test systems with established biotests for macrophytes and (iii) to define necessary time scales in aquatic macrophyte testing. The results showed that fluorescence-based measurements with the Imaging-PAM allow rapid and parallel analysis of large amounts of aquatic macrophyte samples and of toxicants effects of the PSII inhibitors tested on aquatic macrophytes. Measurements revealed a good correlation between obtained median effective concentrations (EC50s) for the new and the established biotest systems. Hence, the Imaging-PAM measuring device is a promising tool to allow fast chemical effect screening for high amounts of samples with little time and material and thus offers scope for high-throughput biotesting using aquatic macrophyte species.

  10. Assessment of heat resistance of bacterial spores from food product isolates by fluorescence monitoring of dipicolinic acid release.

    PubMed

    Kort, Remco; O'Brien, Andrea C; van Stokkum, Ivo H M; Oomes, Suus J C M; Crielaard, Wim; Hellingwerf, Klaas J; Brul, Stanley

    2005-07-01

    This study is aimed at the development and application of a convenient and rapid optical assay to monitor the wet-heat resistance of bacterial endospores occurring in food samples. We tested the feasibility of measuring the release of the abundant spore component dipicolinic acid (DPA) as a probe for heat inactivation. Spores were isolated from the laboratory type strain Bacillus subtilis 168 and from two food product isolates, Bacillus subtilis A163 and Bacillus sporothermodurans IC4. Spores from the lab strain appeared much less heat resistant than those from the two food product isolates. The decimal reduction times (D values) for spores from strains 168, A163, and IC4 recovered on Trypticase soy agar were 1.4, 0.7, and 0.3 min at 105 degrees C, 120 degrees C, and 131 degrees C, respectively. The estimated Z values were 6.3 degrees C, 6.1 degrees C, and 9.7 degrees C, respectively. The extent of DPA release from the three spore crops was monitored as a function of incubation time and temperature. DPA concentrations were determined by measuring the emission at 545 nm of the fluorescent terbium-DPA complex in a microtiter plate fluorometer. We defined spore heat resistance as the critical DPA release temperature (Tc), the temperature at which half the DPA content has been released within a fixed incubation time. We found Tc values for spores from Bacillus strains 168, A163, and IC4 of 108 degrees C, 121 degrees C, and 131 degrees C, respectively. On the basis of these observations, we developed a quantitative model that describes the time and temperature dependence of the experimentally determined extent of DPA release and spore inactivation. The model predicts a DPA release rate profile for each inactivated spore. In addition, it uncovers remarkable differences in the values for the temperature dependence parameters for the rate of spore inactivation, DPA release duration, and DPA release delay.

  11. Predator Foraging in Response to the Mcmurdo Sound Preyscape

    NASA Astrophysics Data System (ADS)

    Daly, K. L.; Ainley, D. G.; Saenz, B.; Ballard, G.; Kim, S.; Jongsomjit, D.

    2016-02-01

    Growing recent evidence indicates that the Ross Sea, Antarctica, food web is structured as a `wasp-waist' system, in which krill and fish constitute the restriction. The abundance/availability of these prey appears to be affected by top-down predation, and to have only minimal coupling with phytoplankton/primary productivity processes. We investigated this issue further by quantifying prey abundance, depth and distribution along the McMurdo Sound fast-ice edge, using an ROV equipped with acoustic sensors and fluorescence sensors and a CTD equipped with a fluorometer, at the same time that we bio-logged the foraging behavior of Adélie Penguins from an adjacent colony and logged the abundance of trophically competing cetaceans and seals. Early in the study period, concentrations of seals and emperor penguins coincided with a location at which high abundance of an under-ice dwelling fish occurred; these predators disappeared with reduction in that prey's abundance and/or the arrival of seal/penguin-eating killer whales at the fast ice edge. The diet of Adélie penguins changed from 100% krill to 50% krill-fish upon the arrival of minke and fish-eating killer whales. Penguin diving depth did not change, nor did they lengthen foraging range as has been observed in the past upon cetacean arrival. However, the prevalence of the mid-water dwelling forage fish (silverfish) decreased within the penguins' foraging range. Apparently, given the chance penguins and cetaceans appear to have targeted the high-energy dense fish instead of krill, and as a result changed prey availability. Penguin diving depth was just beneath an intense phytoplankton bloom of markedly reduced visibility. Our study brings added support for a food web in which top-down forcing is as important as primary production, having implications for managing fisheries in the region.

  12. An aptamer beacon responsive to botulinum toxins.

    PubMed

    Bruno, John G; Richarte, Alicia M; Carrillo, Maria P; Edge, Allison

    2012-01-15

    Sixty candidate DNA aptamers were developed against botulinum neurotoxin (BoNT) type A light chain (LC) from ten rounds of selection, resulting in several identical sequences. Secondary structures of the identical aptamers were compared to structures of previously reported BoNT A DNA aptamers. A series of ten candidate loop structures were selected from this comparison as potential binding pockets and aptamer beacons. These candidate beacons were synthesized with 5'-TYE 665 and 3'-Iowa Black quencher labels for comparison of fluorescence levels as a function of BoNT A LC concentration. Only three of the ten candidates exhibited any fluorescence response to increasing levels of BoNT A LC. However, of the two most responsive candidates, one represented a subset loop of the larger more intensely fluorescent double-looped structure, designated Beacon 10. This beacon yielded a lower limit of detection of 1 ng/mL in buffer using a spectrofluorometer and a portable handheld fluorometer, but also responded substantially to BoNT A, B, E holotoxins and heavy or light chain components even in a dilute soil suspension, but not in 50% human serum. Beacon 10 did not respond strongly to a variety of other divergent peptides, suggesting that it is relatively specific to the level of botulinum toxins and is only useful for environmental testing. Beacon 10 also shared short sequence segments with other published BoNT aptamer DNA sequences, suggesting that these may be points of physical contact between the aptamers and BoNTs.

  13. Real time micro-fiberoptic monitoring of endogenous fluorescence in the rat conceptus during hypoxia.

    PubMed

    Thorsrud, B A; Harris, C

    1993-10-01

    A micro-fiberoptic methodology has been developed for non-invasive, real time measurement of endogenous pyridine nucleotide fluorescence from the surface of the visceral yolk sac (VYS) in intact, viable rat conceptuses. Gestational day (GD) 10-12 conceptuses are maintained in a customized perifusion system, which allows for control of oxygenation, as well as the continuous measurement of pH and oxygen concentration in the effluent perifusate. Miniaturized light guides were constructed by drawing 250 microns ESKA acrylic optical fibers through a stainless steel sheath with a high strength epoxy polymer. A single fiber supplied the excitation signal from a mercury arc lamp at a wavelength of 366 nm. The emission signal was returned via three additional fibers, electronically amplified, processed, and recorded, using a dual channel lamp-compensated fluorometer, optimized for detection of reduced pyridine nucleotides at 455 nm. Endogenous fluorescence in the conceptus was monitored by placing the polished tip of the sensor directly on the surface of the VYS. Oxygen-equilibrated conceptuses, exposed to 100% nitrogen, produced a reproducible biphasic surface fluorescence peak, which returned to baseline levels upon reoxygenation of the perifusate. This biphasic response consisted of an initial rapid rise in fluorescence (phase I), followed by an attenuated rate in fluorescence signal increase (phase II). The hypoxia produced age-dependent rates of fluorescence change during phase I, while phase II remained relatively unchanged throughout GD 10-12. These results demonstrate the ability to monitor endogenous fluorescence, non-invasively and in real time, during the period of organogenesis in the intact rat conceptus and will provide valuable information in studies of embryonic metabolism and response to chemical embryotoxicants.

  14. Response of epilithic lichens to high temperatures at harsh natural and space simulated conditions

    NASA Astrophysics Data System (ADS)

    de La Torre, R.; Horneck, G.; Sancho, L.; Pintado, A.; Rabbow, E.; Scherer, K.; Facius, R.; Deutschmann, U.; Reina, M.

    Studies about the resistance of epilithic lichens to high temperature ranges are not very common until now. Research performed has been focused mainly on resistance of lichens to low temperatures, due the origin of most bipolar lichen species from Antarctica and from Arctic regions. The poiquilohidric nature of lichens gives them the possibility to adopt a latent status when environmental conditions are extreme, that is, when dryness, high solar UV radiation, and extreme temperatures exists, even when this state is long. When humidity returns, photosynthetic activity starts again. To determine the activity at high temperature conditions of the epilithic lichen Rhizocarpon geographicum, which grows at a high mountain region (Sierra de Gredos, Central Spain) with continental climate, we performed a campaign (29.07.03 - 31.07.03), selecting a period of maximal temperatures (July-August), and minimal humidity. Photosynthetic activity, measured with a fluorometer, preadapting and remoistering samples first, were very low or inexistent during this campaign, due to the high superficial temperatures of lichens rocks, minimal humidity values, and high intensities of UV solar irradiation. On the base of these data, we have selected this species as test system for space experiments (i.e. BIOPAN-4 and BIOPAN-5 missions of ESA). Before the BIOPAN-4 mission, the lichens were exposed to the different space parameters (space UV radiation, vaccum and high temperatures), simulated at the space simulation facilities of the Institute of Aerospace Medicine DLR (Germany). The further activity tests were done at the Universidad Complutense de Madrid. The results confirmed the high survival capacity of the selected lichens. We will show the results of photosynthetic activity after the space simulation tests as well as from the campaign performed at the Sierra de Gredos, in summer 2003.

  15. Autonomous Underwater Vehicle Data Management and Metadata Interoperability for Coastal Ocean Studies

    NASA Astrophysics Data System (ADS)

    McCann, M. P.; Ryan, J. P.; Chavez, F. P.; Rienecker, E.

    2004-12-01

    Data from over 1000 km of Autonomous Underwater Vehicle (AUV) surveys of Monterey Bay have been collected and cataloged in an ocean observatory data management system. The Monterey Bay Aquarium Institute's AUV is equipped with a suite of instruments that include a conductivity, temperature, depth (CTD) instrument, transmissometers, a fluorometer, a nitrate sensor, and an inertial navigation system. Data are logged on the vehicle and upon completion of a survey XML descriptions of the data are submitted to the Shore Side Data System (SSDS). Instrument data are then processed on shore to apply calibrations and produce scientifically useful data products. The SSDS employs a data model that tracks data from the instrument that created it through all the consuming processes that generate derived products. SSDS employs OPeNDAP and netCDF to provide data set interoperability at the data level. The core of SSDS is the metadata that is the catalog of these data sets and their relation to all other relevant data. The metadata is managed in a relational database and governed by a Enterprise Java Bean (EJB) server application. Cross-platform Java applications have been written to manage and visualize these data. A Java Swing application - the Hierarchical Ocean Observatory Visualization and Editing System (HOOVES) - has been developed to provide visualization of data set pedigree and data set variables. Because the SSDS data model is generalized according to "Data Producers" and "Data Containers" many different types of data can be represented in SSDS allowing for interoperability at a metadata level. Comparisons of appropriate data sets, whether they are from an autonomous underwater vehicle or from a fixed mooring are easily made using SSDS. The authors will present the SSDS data model and show examples of how the model helps organize data set metadata allowing for data discovery and interoperability. With improved discovery and interoperability the system is helping us

  16. Plant experiments with light-emitting diode module in Svet space greenhouse

    NASA Astrophysics Data System (ADS)

    Ilieva, Iliyana; Ivanova, Tania; Naydenov, Yordan; Dandolov, Ivan; Stefanov, Detelin

    Light is necessary for photosynthesis and shoot orientation in the space plant growth facilities. Light modules (LM) must provide sufficient photosynthetic photon flux for optimal efficiency of photosynthetic processes and also meet the constraints for power, volume and mass. A new LM for SVET Space Greenhouse using Cree R XLamp R 7090 XR light-emitting diodes (LEDs) is developed. Three types of monochromic LEDs emitting in the red, green, and blue region of the spectrum are used. The new LM contains 36 LED spots - 30 LED spots with one red, green and blue LED and 6 LED spots with three red LEDs. DMX programming device controls the LED spots and can set 231 levels of light intensity thus achieving Photosynthetic Photon Flux Density (PPFD) in the range 0-400 µmol.m-2 .s-1 and different percentages of the red, green and blue light, depending on the experimental objectives. Two one-month experiments with "salad-type" plants - lettuce and chicory were carried at 400 µmol.m-2 .s-1 PPFD (high light - HL) and 220 µmol.m-2 .s-1 PPFD (low light - LL) and composition 70% red, 20% green and 10% blue light. In vivo modulated chlorophyll fluorescence was measured by a PAM fluorometer on leaf discs and the following parameters: effective quantum yield of Photosystem II (ΦP SII ) and non-photochemical quenching (NPQ) were calculated. Both lettuce and chicory plants grown at LL express higher photochemical activity of Photosystem II (PSII) than HL grown plants, evaluated by the actual PSII quantum yield, ΦP SII . The calculated steady state NPQ values did not differ significantly in lettuce and chicory. The rapid phase of the NPQ increase was accelerated in all studied LL leaves. In conclusion low light conditions ensured more effective functioning of PSII than HL when lettuce and chicory plants were grown at 70% red, 20% green and 10% blue light composition.

  17. The validation of a new vascular damage assay for photodynamic therapy agents.

    PubMed

    Bellnier, D A; Potter, W R; Vaughan, L A; Sitnik, T M; Parsons, J C; Greco, W R; Whitaker, J; Johnson, P; Henderson, B W

    1995-11-01

    The therapeutic effect of photodynamic therapy (PDT: photodynamic sensitizer + light) is partly due to vascular damage. This report describes a new vascular photodamage assay for PDT agents and a validation of the assay. The method described here quantitates changes in tissue blood perfusion based on the relative amount of injected fluorescein dye in treated and untreated tissues. A specially designed fluorometer uses chopped monochromatic light from an argon laser as a source for exciting fluorescein fluorescence. The fluorescent light emitted from the tissue is collected by a six element fiberoptic array, filtered and delivered to a photodiode detector coupled to a phase-locked amplifier for conversion to a voltage signal for recording. This arrangement permits a rather simple, inexpensive construction and allows for the simultaneous use of the argon laser by other investigators. The routine assay for characterizing a specific photosensitizer at a standard dose consists of the sequential allocation of eight mice to a set of different light doses designed to span the dose-response range of fluorescein fluorescence exclusion (measured 8-10 min after fluorescein injection). The assay validation experiment used an anionic photosensitizer, 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a at a dose of 0.4 mumol/kg. The parameter estimates (n = 34 mice) from fitting the standard Hill dose-response model to the data were: median fluorescence exclusion light dose FE50 = 275 +/- 8.3 J/cm2 and Hill sigmoidicity parameter m = -3.66 +/- 0.28. Subsets of the full data set randomly selected to simulate a standard eight mice experiment yielded similar parameter estimates. The new assay provides reliable estimates of PDT vascular damage with a frugal sequential experimental design.

  18. Basin-scale spatio-temporal variability and control of phytoplankton photosynthesis in the Baltic Sea: The first multiwavelength fast repetition rate fluorescence study operated on a ship-of-opportunity

    NASA Astrophysics Data System (ADS)

    Houliez, Emilie; Simis, Stefan; Nenonen, Susanna; Ylöstalo, Pasi; Seppälä, Jukka

    2017-05-01

    This study presents the results of the first field application of a flow-through multi-wavelength Fast Repetition Rate fluorometer (FRRF) equipped with two excitation channels (458 and 593 nm). This device aims to improve the measurement of mixed cyanobacteria and algae community's photosynthetic parameters and was designed to be easily incorporated into existing ferrybox systems. We present a spatiotemporal analysis of the maximum photochemical efficiency (Fv/Fm) and functional absorption cross section (σPSII) recorded from April to August 2014 on a ship-of-opportunity commuting twice per week between Helsinki (Finland) and Travemünde (Germany). Temporal variations of Fv/Fm and σPSII differed between areas of the Baltic Sea. However, even though the Baltic Sea is characterized by several physico-chemical gradients, no gradient was observed in Fv/Fm and σPSII spatial distribution suggesting complex interactions between biotic and abiotic controls. σPSII was sensitive to phytoplankton seasonal succession and thus differed according to the wavelength used to excite photosystems II (PSII) pigments. This was particularly true in summer when high σPSII(593) values were observed later and longer than high σPSII(458) values, reflecting the role of cyanobacteria in photosynthetic light uptake measured at community scale. In contrast, Fv/Fm variations were similar after excitation at 458 nm or 593 nm suggesting that the adjustment of Fv/Fm in response to environmental factors was similar for the different groups (algae vs. cyanobacteria) present within the phytoplankton community.

  19. Evaluation of Algal Biofilms on Indium Tin Oxide (ITO) for Use in Biophotovoltaic Platforms Based on Photosynthetic Performance

    PubMed Central

    Ng, Fong-Lee; Phang, Siew-Moi; Periasamy, Vengadesh; Yunus, Kamran; Fisher, Adrian C.

    2014-01-01

    In photosynthesis, a very small amount of the solar energy absorbed is transformed into chemical energy, while the rest is wasted as heat and fluorescence. This excess energy can be harvested through biophotovoltaic platforms to generate electrical energy. In this study, algal biofilms formed on ITO anodes were investigated for use in the algal biophotovoltaic platforms. Sixteen algal strains, comprising local isolates and two diatoms obtained from the Culture Collection of Marine Phytoplankton (CCMP), USA, were screened and eight were selected based on the growth rate, biochemical composition and photosynthesis performance using suspension cultures. Differences in biofilm formation between the eight algal strains as well as their rapid light curve (RLC) generated using a pulse amplitude modulation (PAM) fluorometer, were examined. The RLC provides detailed information on the saturation characteristics of electron transport and overall photosynthetic performance of the algae. Four algal strains, belonging to the Cyanophyta (Cyanobacteria) Synechococcus elongatus (UMACC 105), Spirulina platensis. (UMACC 159) and the Chlorophyta Chlorella vulgaris (UMACC 051), and Chlorella sp. (UMACC 313) were finally selected for investigation using biophotovoltaic platforms. Based on power output per Chl-a content, the algae can be ranked as follows: Synechococcus elongatus (UMACC 105) (6.38×10−5 Wm−2/µgChl-a)>Chlorella vulgaris UMACC 051 (2.24×10−5 Wm−2/µgChl-a)>Chlorella sp.(UMACC 313) (1.43×10−5 Wm−2/µgChl-a)>Spirulina platensis (UMACC 159) (4.90×10−6 Wm−2/µgChl-a). Our study showed that local algal strains have potential for use in biophotovoltaic platforms due to their high photosynthetic performance, ability to produce biofilm and generation of electrical power. PMID:24874081

  20. Photosynthetic properties of spring geophytes assessed by chlorophyll fluorescence analysis.

    PubMed

    Recchia, Irene; Sparla, Francesca; Pupillo, Paolo

    2017-09-01

    Since spring ephemerals are credited to be all "sun" species with unusually elevate photosynthesis, in contrast to shade-tolerant trees and understory geophytes with a long aboveground cycle, we examined the photosynthetic efficiency of 6 woody species, 9 long-cycle geophytes, and 8 spring ephemeral geophytes using blue flashes of increasing energy with the Imaging PAM fluorometer. Several parameters were obtained: quantum yield of electron transport (ΦETR) or of PSII (ΦPSII), maximum measured photosynthesis rate (ETRhv), maximum extrapolated rate of photosynthesis (ETRem), half-saturating photon flux density (KPAR), and in some cases photochemical (qP) and non-photochemical quenching (NPQ). Results confirm the ecological consistency of the three plant groups, with internal differences. Woody species have low ETRem and KPAR values with good ΦETR; long-cycle herbs have low ETRem and ΦETR and moderate KPAR values; spring ephemerals have elevate ΦETR, ETRem and KPAR values. The mean ETRem of ephemerals of 91 μmol m(-2) s(-1) exceeds that of long-cycle herbs 2.9-fold and woody species 4.8-fold, and corresponds to 19 μmol CO2 m(-2) s(-1) by assuming an ETR/ΦCO2 ratio of 4.7. Highest photosynthesis rates and KPAR were exhibited by five ephemerals (Eranthis, Erythronium, Narcissus, Scilla, Tulipa) with peak ETRem values equivalent to ∼40 μmol CO2 m(-2) s(-1) or ∼60 μmol CO2 (g Chl)(-1) s(-1) ("sun" species). According to a new, fluorescence based heliophily index, all trees and five long-cycle herbs were definitely "shade" species, while four long-cycle herbs and three ephemerals were intermediate shade-tolerant. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  1. Interaction of UV radiation and inorganic carbon supply in the inhibition of photosynthesis: spectral and temporal responses of two marine picoplankters.

    PubMed

    Sobrino, Cristina; Neale, Patrick J; Lubián, Luis M

    2005-01-01

    The effect of ultraviolet radiation (UVR) on inhibition of photosynthesis was studied in two species of marine picoplankton with different carbon concentration mechanisms: Nannochloropsis gaditana Lubian possesses a bicarbonate uptake system and Nannochloris atomus Butcher a CO2 active transport system. Biological weighting functions (BWFs) for inhibition of photosynthesis by UVR and photosynthesis vs irradiance (PI) curves for photosynthetically active radiation (PAR) were estimated for both species grown with an enriched CO2 supply (high dissolved inorganic carbon [DIC]: 1% CO2 in air) and in atmospheric CO2 levels (low DIC: 0.03% CO2). The response to UVR and PAR exposures was different in each species depending on the DIC treatment. Under PAR exposure, rates of maximum photosynthesis were similar between treatments in N. gaditana. However, the cultures growing in high DIC had lower sensitivity to UVR than the low DIC cultures. In contrast, N. atomus had higher rates of photosynthesis under PAR exposure with high DIC, but the BWFs were not significantly different between treatments. The results suggest that one or more processes in N. gaditana associated with HCO3- transport are target(s) for UV photodamage because there was relatively less UV inhibition of the high DIC-grown cultures in which inorganic carbon fixation is supplied by passive CO2 diffusion. Time courses of photochemical efficiency in PAR, during UV exposure and during subsequent recovery in PAR, were determined using a pulse amplitude modulated fluorometer. The results were consistent with the BWFs. In all time courses, a steady state was obtained after an initial decrease, consistent with a dynamic balance between damage and repair as found for other phytoplankton. However, the relationship of response to exposure showed a steep decline in activity that is consistent with a constant rate of repair. A novel feature of a model developed from a constant repair rate is an explicit threshold for

  2. Field and controlled environment measurements show strong seasonal acclimation in photosynthesis and respiration potential in boreal Scots pine

    PubMed Central

    Kolari, Pasi; Chan, Tommy; Porcar-Castell, Albert; Bäck, Jaana; Nikinmaa, Eero; Juurola, Eija

    2014-01-01

    Understanding the seasonality of photosynthesis in boreal evergreen trees and its control by the environment requires separation of the instantaneous and slow responses, as well as the dynamics of light reactions, carbon reactions, and respiration. We determined the seasonality of photosynthetic light response and respiration parameters of Scots pine (Pinus sylvestris L.) in the field in southern Finland and in controlled laboratory conditions. CO2 exchange and chlorophyll fluorescence were measured in the field using a continuously operated automated chamber setup and fluorescence monitoring systems. We also carried out monthly measurements of photosynthetic light, CO2 and temperature responses in standard conditions with a portable IRGA and fluorometer instrument. The field and response measurements indicated strong seasonal variability in the state of the photosynthetic machinery with a deep downregulation during winter. Despite the downregulation, the photosynthetic machinery retained a significant capacity during winter, which was not visible in the field measurements. Light-saturated photosynthesis (Psat) and the initial slope of the photosynthetic light response (α) obtained in standard conditions were up to 20% of their respective summertime values. Respiration also showed seasonal acclimation with peak values of respiration in standard temperature in spring and decline in autumn. Spring recovery of all photosynthetic parameters could be predicted with temperature history. On the other hand, the operating quantum yield of photosystem II and the initial slope of photosynthetic light response stayed almost at the summertime level until late autumn while at the same time Psat decreased following the prevailing temperature. Comparison of photosynthetic parameters with the environmental drivers suggests that light and minimum temperature are also decisive factors in the seasonal acclimation of photosynthesis in boreal evergreen trees. PMID:25566291

  3. Decreased hydrogen peroxide production and mitochondrial respiration in skeletal muscle but not cardiac muscle of the green-striped burrowing frog, a natural model of muscle disuse.

    PubMed

    Reilly, Beau D; Hickey, Anthony J R; Cramp, Rebecca L; Franklin, Craig E

    2014-04-01

    Suppression of disuse-induced muscle atrophy has been associated with altered mitochondrial reactive oxygen species (ROS) production in mammals. However, despite extended hindlimb immobility, aestivating animals exhibit little skeletal muscle atrophy compared with artificially immobilised mammalian models. Therefore, we studied mitochondrial respiration and ROS (H2O2) production in permeabilised muscle fibres of the green-striped burrowing frog, Cyclorana alboguttata. Mitochondrial respiration within saponin-permeabilised skeletal and cardiac muscle fibres was measured concurrently with ROS production using high-resolution respirometry coupled to custom-made fluorometers. After 4 months of aestivation, C. alboguttata had significantly depressed whole-body metabolism by ~70% relative to control (active) frogs, and mitochondrial respiration in saponin-permeabilised skeletal muscle fibres decreased by almost 50% both in the absence of ADP and during oxidative phosphorylation. Mitochondrial ROS production showed up to an 88% depression in aestivating skeletal muscle when malate, succinate and pyruvate were present at concentrations likely to reflect those in vivo. The percentage ROS released per O2 molecule consumed was also ~94% less at these concentrations, indicating an intrinsic difference in ROS production capacities during aestivation. We also examined mitochondrial respiration and ROS production in permeabilised cardiac muscle fibres and found that aestivating frogs maintained respiratory flux and ROS production at control levels. These results show that aestivating C. alboguttata has the capacity to independently regulate mitochondrial function in skeletal and cardiac muscles. Furthermore, this work indicates that ROS production can be suppressed in the disused skeletal muscle of aestivating frogs, which may in turn protect against potential oxidative damage and preserve skeletal muscle structure during aestivation and following arousal.

  4. Synergistic Effects of Nano-Sized Titanium Dioxide and Zinc on the Photosynthetic Capacity and Survival of Anabaena sp.

    PubMed Central

    Tang, Yulin; Li, Shuyan; Qiao, Junlian; Wang, Hongtao; Li, Lei

    2013-01-01

    Anabaena sp. was used to examine the toxicity of exposure to a nano-TiO2 suspension, Zn2+ solution, and mixtures of nano-TiO2 and Zn2+ suspensions. Typical chlorophyll fluorescence parameters, including effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse-amplitude modulated fluorometer. Nano-TiO2 particles exhibited no significant toxicity at concentrations lower than 10.0 mg/L. The 96 h concentration for the 50% maximal effect (EC50) of Zn2+ alone to Anabaena sp. was 0.38 ± 0.004 mg/L. The presence of nano-TiO2 at low concentrations (<1.0 mg/L) significantly enhanced the toxicity of Zn2+ and consequently reduced the EC50 value to 0.29 ± 0.003 mg/L. However, the toxicity of the Zn2+/TiO2 system decreased with increasing nano-TiO2 concentration because of the substantial adsorption of Zn2+ by nano-TiO2. The toxicity curve of the Zn2+/TiO2 system as a function of incremental nano-TiO2 concentrations was parabolic. The toxicity significantly increased at the initial stage, reached its maximum, and then decreased with increasing nano-TiO2 concentration. Hydrodynamic sizes, concentration of nano-TiO2 and Zn2+ loaded nano-TiO2 were the main parameters for synergistic toxicity. PMID:23852017

  5. Estimating phytoplankton photosynthesis by active fluorescence

    SciTech Connect

    Falkowski, P.G.; Kolber, Z.

    1992-01-01

    Photosynthesis can be described by target theory, At low photon flux densities, photosynthesis is a linear function of irradiance (I), The number of reaction centers (n), their effective absorption capture cross section {sigma}, and a quantum yield {phi}. As photosynthesis becomes increasingly light saturated, an increased fraction of reaction centers close. At light saturation the maximum photosynthetic rate is given as the product of the number of reaction centers (n) and their maximum electron transport rate (I/{tau}). Using active fluorometry it is possible to measure non-destructively and in real time the fraction of open or closed reaction centers under ambient irradiance conditions in situ, as well as {sigma} and {phi} {tau} can be readily, calculated from knowledge of the light saturation parameter, I{sub k} (which can be deduced by in situ by active fluorescence measurements) and {sigma}. We built a pump and probe fluorometer, which is interfaced with a CTD. The instrument measures the fluorescence yield of a weak probe flash preceding (f{sub 0}) and succeeding (f{sub 0}) a saturating pump flash. Profiles of the these fluorescence yields are used to derive the instantaneous rate of gross photosynthesis in natural phytoplankton communities without any incubation. Correlations with short-term simulated in situ radiocarbon measurements are extremely high. The average slope between photosynthesis derived from fluorescence and that measured by radiocarbon is 1.15 and corresponds to the average photosynthetic quotient. The intercept is about 15% of the maximum radiocarbon uptake and corresponds to the average net community respiration. Profiles of photosynthesis and sections showing the variability in its composite parameters reveal a significant effect of nutrient availability on biomass specific rates of photosynthesis in the ocean.

  6. Estimating phytoplankton photosynthesis by active fluorescence

    SciTech Connect

    Falkowski, P.G.; Kolber, Z.

    1992-10-01

    Photosynthesis can be described by target theory, At low photon flux densities, photosynthesis is a linear function of irradiance (I), The number of reaction centers (n), their effective absorption capture cross section {sigma}, and a quantum yield {phi}. As photosynthesis becomes increasingly light saturated, an increased fraction of reaction centers close. At light saturation the maximum photosynthetic rate is given as the product of the number of reaction centers (n) and their maximum electron transport rate (I/{tau}). Using active fluorometry it is possible to measure non-destructively and in real time the fraction of open or closed reaction centers under ambient irradiance conditions in situ, as well as {sigma} and {phi} {tau} can be readily, calculated from knowledge of the light saturation parameter, I{sub k} (which can be deduced by in situ by active fluorescence measurements) and {sigma}. We built a pump and probe fluorometer, which is interfaced with a CTD. The instrument measures the fluorescence yield of a weak probe flash preceding (f{sub 0}) and succeeding (f{sub 0}) a saturating pump flash. Profiles of the these fluorescence yields are used to derive the instantaneous rate of gross photosynthesis in natural phytoplankton communities without any incubation. Correlations with short-term simulated in situ radiocarbon measurements are extremely high. The average slope between photosynthesis derived from fluorescence and that measured by radiocarbon is 1.15 and corresponds to the average photosynthetic quotient. The intercept is about 15% of the maximum radiocarbon uptake and corresponds to the average net community respiration. Profiles of photosynthesis and sections showing the variability in its composite parameters reveal a significant effect of nutrient availability on biomass specific rates of photosynthesis in the ocean.

  7. Effects of ultraviolet radiation on the productivity and composition of freshwater phytoplankton communities.

    PubMed

    Harrison, Joel W; Smith, Ralph E H

    2009-09-01

    The net influence of ultraviolet radiation (UVR; 280-400 nm) on freshwater phytoplankton communities depends on the photon flux density, duration, and spectral quality of exposure and the UVR sensitivity of the assemblage in terms of photosynthetic impairment, biochemical composition, and nutrient assimilation mechanisms. Such effects are mitigated to varying degrees by photoacclimation and selective adaptation at the community level. Variation in UVR penetration among lakes is considerable, largely due to differences in chromophoric dissolved organic matter concentrations. Documented losses of areal daily primary production in lakes due to UVR range from negligible (2.5%) to appreciable (26%). UVR has the potential to alter algal biochemical composition and therefore indirectly affect higher trophic levels. There is evidence that algal nutritional status can influence UVR sensitivity, and that UVR can inhibit uptake and assimilation of inorganic nutrients, but results have been inconsistent. Taxonomic variability in susceptibility to the effects of UVR exists, and likely reflects variation in cell size and shape, concentrations of photoprotective pigments, and capacity to repair UVR photodamage. Suggestions for future research include: (1) resolution of taxon-specific UVR responses by way of single-cell techniques (e.g. enzyme-labelled fluorescence assays, microscope-based variable fluorometers) and (2) systematic comparative studies to link UVR exposure in natural habitats to community responses using the biological weighting function modelling approach. A more robust understanding of how sensitivity to UVR varies according to taxon and habitat is needed if predictions of its role in ecosystem functioning, particularly in connection with climate change, are to be meaningful.

  8. Implication of long-distance cytoplasmic transport into dynamics of local pH on the surface of microinjured Chara cells.

    PubMed

    Bulychev, Alexander A; Komarova, Anna V

    2017-01-01

    Cytoplasmic streaming is essential for intracellular communications but its specific functions are not well known. In Chara corallina internodes, long-distance interactions mediated by cyclosis are clearly evident with microscopy-pulse amplitude modulation (PAM) fluorometer under application of localized light (LL) pulses to a remote cell region. Measurements of LL-induced profiles of chlorophyll fluorescence F' at various distances from the LL source suggest that illuminated chloroplasts release into the streaming cytoplasm excess reducing equivalents that are entrained by the fluid flow and transiently reduce the intersystem electron carriers in chloroplasts of downstream shaded areas. The reducing equivalents propagate to distances up to 4.5 mm from the LL source, with the transport rate nearly equal to the velocity of liquid flow. The F' transients disappeared after the arrest of streaming with cytochalasin D and reappeared upon its recovery in washed cells. The F' responses to a distant LL were used as an indicator for the passage of cytosolic reductants across the analyzed cell area during measurements of cell surface pH (pHo) in intact and microperforated internodes. In microwounded cell regions, the LL-induced increase in F' occurred synchronously with the increase in pHo, by contrast to a slight decrease in pHo observed prior to perforation. The results show that reducing agents transported with the cytoplasmic flow are involved in rapid pH changes on the surface of microinjured cells. A possibility is considered that cytoplasmic reductants are processed by stress-activated plasmalemmal NADPH oxidase carrying electrons to oxygen with the eventual H(+) consumption on the outer cell side.

  9. Application of portable in situ UV fluorescence sensors in natural and engineered aquatic systems.

    NASA Astrophysics Data System (ADS)

    Fox, Bethany; Rushworth, Cathy; Atrridge, John

    2016-04-01

    Natural organic matter (NOM) is ubiquitous throughout aquatic systems. This heterogeneous mixture of organic matter is central for aquatic ecosystems and, both local and global, biogeochemical cycling. Improvements in technology and data analysis has allowed for advances in the understanding and characterisation of aquatic organic matter. However, much of the technological expansions have focussed on benchtop instruments. In recent years, there has been interest in the continued development of portable in situ sensors for monitoring NOM characteristics within a wide range of applications, spanning both natural and engineered systems. The UviLux (Chelsea Technologies Group Ltd., UK) is an in situ portable UV fluorescence sensor that can be configured to monitor a range of NOM in aquatic systems, as well as anthropogenic inputs such as polycyclic aromatic hydrocarbons (PAH) and optical brighteners. Here we will focus on the use of the Tryptophan and CDOM UviLux sensors across a variety of applications in both natural systems, such as rivers and leachate into groundwater, and engineered systems, including drinking water and waste water treatment. Recent work has focused on standardising the fluorescence output across the UviLux range of sensors, reporting data in quinine sulphate units (QSU), which enables the output from two different fluorometers to be directly compared both to each other, and to bench-top data. A key advantage of deploying multiple sensors is the ability to fingerprint the fluorescence, by providing, for example, a Tryptophan/CDOM ratio. From the data collected, the ratio of the different fluorescence regions has been shown to provide more robust in situ data and help identify true temporal variations and patterns across multiple applications and sampling locations.

  10. Effects of several variables on whole effluent toxicity test performance and interpretation

    SciTech Connect

    Markle, P.J.; Gully, J.R.; Baird, R.B.; Nakada, K.M.; Bottomley, J.P.

    2000-01-01

    Protocol changes and options contained within US Environmental Protection Agency whole effluent toxicity tests represent variables that have the potential to affect bioassay performance and interpretation of results. Variables evaluated in this study include: the change in allowable age in the Pimephales promelas acute bioassay from up to 90 d to a maximum of 14 d, age-specific acute responses of P. promelas among the allowable ages of 1 to 14 d, change in the chronic growth endpoint definition from final mass to biomass, differences between hemacytometer and fluorometer measurements in the Selenastrum capricornutum protocol, and options for statistical interpretation of species sensitivity in multiple test/species screening bioassays. Clear age-related sensitivity and precision differences were observed in acute responses of P. promelas. Results obtained using the younger age classes were typically more variable in studies of both 1- to 14-d-old and 14- to 90-d-old P. promelas. In the experiments on 1- to 14-d-old organisms, larvae at 1 d of age were significantly less sensitive. In the tests on 14- to 90-d-old organisms, the 14-d-old organisms were significantly less sensitive. The change in endpoint definition in the P. promelas chronic bioassay resulted in an apparent increase in toxic response in the inhibition concentration (ICp) value for each bioassay, evaluated by the biomass method, with no general improvement in statistical interest precision estimates and no predictable impact on the no-observed-effect concentration endpoint. Fluorometric scoring in the Selenastrum bioassay was significantly more precise and better capable of estimating counts than hemacytometer measurements. Discrepancies associated with commonly used statistical endpoints used to determine the most sensitive species were identified, and potential solutions were proposed.

  11. Freezing cytorrhysis and critical temperature thresholds for photosystem II in the peat moss Sphagnum capillifolium.

    PubMed

    Buchner, Othmar; Neuner, Gilbert

    2010-07-01

    Leaflets of Sphagnum capillifolium were exposed to temperatures from -5 degrees C to +60 degrees C under controlled conditions while mounted on a microscope stage. The resultant cytological response to these temperature treatments was successfully monitored using a light and fluorescence microscope. In addition to the observable cytological changes during freezing cytorrhysis and heat exposure on the leaflets, the concomitant critical temperature thresholds for inactivation of photosystem II (PS II) were studied using a micro fibre optic and a chlorophyll fluorometer mounted to the microscope stage. Chlorophyllous cells of S. capillifolium showed extended freezing cytorrhysis immediately after ice nucleation at -1.1 degrees C in the water in which the leaflets were submersed during the measurement. The occurrence of freezing cytorrhysis, which was visually manifested by cell shrinkage, was highly dynamic and was completed within 2 s. A total reduction of the mean projected diameter of the chloroplast containing area during freezing cytorrhysis from 8.9 to 3.8 microm indicates a cell volume reduction of approximately -82%. Simultaneous measurement of chlorophyll fluorescence of PS II was possible even through the frozen water in which the leaf samples were submersed. Freezing cytorrhysis was accompanied by a sudden rise of basic chlorophyll fluorescence. The critical freezing temperature threshold of PS II was identical to the ice nucleation temperature (-1.1 degrees C). This is significantly above the temperature threshold at which frost damage to S. capillifolium leaflets occurs (-16.1 degrees C; LT(50)) which is higher than observed in most higher plants from the European Alps during summer. High temperature thresholds of PS II were 44.5 degrees C which is significantly below the heat tolerance of chlorophyllous cells (49.9 degrees C; LT(50)). It is demonstrated that light and fluorescence microscopic techniques combined with simultaneous chlorophyll fluorescence

  12. UV Screening in Native and Non-native Plant Species in the Tropical Alpine: Implications for Climate Change-Driven Migration of Species to Higher Elevations.

    PubMed

    Barnes, Paul W; Ryel, Ronald J; Flint, Stephan D

    2017-01-01

    Ongoing changes in Earth's climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV)-B (280-315 nm) radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A) in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8) and non-native (mean = 5.8%; n = 11) species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees) were represented solely by native species whereas herbaceous growth forms (grasses and forbs) were dominated by non-native species. Along an elevation gradient spanning 2600-3800 m, TUV A was variable (mean range = 6.0-11.2%) and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3%) and did not vary with elevation in the native V. reticulatum

  13. UV Screening in Native and Non-native Plant Species in the Tropical Alpine: Implications for Climate Change-Driven Migration of Species to Higher Elevations

    PubMed Central

    Barnes, Paul W.; Ryel, Ronald J.; Flint, Stephan D.

    2017-01-01

    Ongoing changes in Earth’s climate are shifting the elevation ranges of many plant species with non-native species often experiencing greater expansion into higher elevations than native species. These climate change-induced shifts in distributions inevitably expose plants to novel biotic and abiotic environments, including altered solar ultraviolet (UV)-B (280–315 nm) radiation regimes. Do the greater migration potentials of non-native species into higher elevations imply that they have more effective UV-protective mechanisms than native species? In this study, we surveyed leaf epidermal UV-A transmittance (TUV A) in a diversity of plant species representing different growth forms to test whether native and non-native species growing above 2800 m elevation on Mauna Kea, Hawaii differed in their UV screening capabilities. We further compared the degree to which TUV A varied along an elevation gradient in the native shrub Vaccinium reticulatum and the introduced forb Verbascum thapsus to evaluate whether these species differed in their abilities to adjust their levels of UV screening in response to elevation changes in UV-B. For plants growing in the Mauna Kea alpine/upper subalpine, we found that adaxial TUV A, measured with a UVA-PAM fluorometer, varied significantly among species but did not differ between native (mean = 6.0%; n = 8) and non-native (mean = 5.8%; n = 11) species. When data were pooled across native and non-native taxa, we also found no significant effect of growth form on TUV A, though woody plants (shrubs and trees) were represented solely by native species whereas herbaceous growth forms (grasses and forbs) were dominated by non-native species. Along an elevation gradient spanning 2600–3800 m, TUV A was variable (mean range = 6.0–11.2%) and strongly correlated with elevation and relative biologically effective UV-B in the exotic V. thapsus; however, TUV A was consistently low (3%) and did not vary with elevation in the native V

  14. AB104. Glucose-6 phospate dehydrogenase deficiency among mongolian neonates

    PubMed Central

    Batjargal, Khishigjargal; Nansal, Gerelmaa; Zagd, Gerelmaa; Ganbaatar, Erdenetuya

    2015-01-01

    Background and objective Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzyme deficiency in humans, affecting 400 million people worldwide and a high prevalence in persons of African, Middle Asian countries. The most common clinical manifestations are neonatal jaundice and acute hemolytic anemia, which is caused by the impairment of erythrocyte’s ability to remove harmful oxidative stress triggered by exogenous agents such as drugs, infection, or fava bean ingestion. Neonatal hyperbilirubinemia caused by G6PD is strongly associated with mortality and long-term neurodevelopmental impairment. The study aims to determine a level of G6PD in healthy neonates. Methods We obtained blood spot samples from 268 infants around 24-72 hours in their age who has unsuspected intranatal and neonatal disorders. Glucose 6 phosphate dehydrogenase “Perkin Elmer, Finland” level is determined by Victor 2D Fluorometer assay, developing of neonatal jaundice is examined by recall. Results The76.5% of all participants (n=205) was assessed 4.36±1.15 Ug/Hb in normal reference range of G6PD, other 23.5% (n=63) was 0.96±0.51 Ug/Hb with G6PD deficiency. In the both sex, 51.5% of male 0.88±0.46 Ug/Hb (n=33) and 47.6% of female (n=30) 0.97±0.55 Ug/Hb was assessed with G6PD deficiency. Developing Jaundice period in number of 63 neonates with G6PD deficiency, 86% of neonates (n=54) was in 1-4 days, 4% of neonates (n=3) was in 5-7 days and there is no sign of jaundice in 9% (n=6). Therefore neonates with G6PD deficiency, 53.9% (n=34) continued jaundice more than two weeks. Conclusions G6PD deficiency was determined in male neonates (51.5%) more than female (47.6%). The 76.5% of all participants (n=205) was assessed 4.36±1.15 Ug/Hb in normal reference range of G6PDH other 23.5% (n=63) of all participants was 0.96±0.51 Ug/Hb with G6PD deficiency. It shows that G6PD might be one potential risk of neonatal jaundice and hyperbilirubinemia in neonates in Mongolia.

  15. Separation of Single-Walled Carbon Nanotubes with DEP-FFF

    NASA Technical Reports Server (NTRS)

    Schmidt, Howard K.; Peng, Haiqing; Alvarez, Noe; Mendes, Manuel; Pasquali, Matteo

    2011-01-01

    A process using a modified dielectrophoresis device separates single-walled carbon nanotubes (SWNTs) according to their polarizability in electric fields. This depends on the size and dielectric constant of individual nanotubes and easily separates metallic from semiconducting nanotubes. Separation by length has also been demonstrated. Partial separation (enrichment) according to bandgap (which is linked to polarizability) has also been shown and can be improved to full separation of individual types of semiconducting SWNTs with better control over operational parameters and the length of SWNT starting material. This process and device can be scaled affordably to generate useful amounts of semiconducting SWNTs for electronic device development and production. In this study, a flow injection dielectrophoresis technique was used with a modified dielectrophoresis device. The length, width, and height of the modified chamber were 28, 2.5, and 0.025 cm, respectively. On the bottom of the chamber, there are two arrays of 50-m-wide, 2-m-thick gold electrodes, which are connected to an AC voltage generator and are alternately arranged so that every electrode is adjacent to two electrodes of the opposite polar. There is an additional plate electrode on the top of the chamber that is negatively biased. During the experiment, a syringe pump constantly pumps in the mobile phase, 1-percent sodium dodecylbenzene sulfonate (SDBS) solution, into the chamber. The frequency and voltage are set to 1 MHz and 10 V peak-to-peak, respectively. About 150 micro-L of SWNTs in 1- percent SDBS decanted solution are injected to the mobile phase through a septum near the entrance of the chamber. The flow rate of the mobile phase is set to 0.02 cu cm/min. The injected SWNTs sample flows through the chamber before it is lead into a fluorescence flow-through cell and collected for further analysis. The flow-through cell has three windows, thus allowing the fluorometer to collect fluorescence

  16. Ultraviolet B-photoprotection efficiency of mesocosm-enclosed natural phytoplankton communities from different latitudes: Rimouski (Canada) and Ubatuba (Brazil).

    PubMed

    Mohovic, Bruna; Gianesella, Sônia M F; Laurion, Isabelle; Roy, Suzanne

    2006-01-01

    Photoprotection against UV-B radiation (UVBR; 280-320 nm) was examined in natural phytoplankton communities from two coastal environments at different latitudes: temperate Rimouski (Canada) and tropical Ubatuba (Brazil). Mesocosm experiments were performed at these sites to examine the response of phytoplankton to increases in UVBR that corresponded to local depletions of 30% and 60% in atmospheric ozone levels (low and high UVBR treatments, respectively). A fluorescence method using a pulse amplitude modulation fluorometer (Xe-PAM, Walz, Germany) with selective UV filters was used to estimate photoprotection, and these results were compared with an index of mycosporine-like amino acid (MAA) concentrations determined using spectrophotometry of methanol extracts. The present study provided the first evidence, to our knowledge, of the suitability of this in vivo fluorescence method for the estimation of UV photoprotection efficiency in natural phytoplankton. No significant differences were found for most of the variables analyzed between the light treatments used at both sites, but differences were found between sites throughout the duration of the experiments. Vertical mixing, used to maintain cells in suspension, likely alleviated serious UVBR-induced damage during both experiments by reducing the length of time of exposure to the highest UVBR irradiances at the surface. In Rimouski, this was the main factor minimizing the effects of treatment, because optical properties of the coastal seawater rapidly attenuated UVBR throughout the water column of the ca 2 m deep mesocosms. In this location, synthesis of MAAs and photoprotective pigments likely contributed to the observed phototolerance of phytoplankton and, hence, to their growth; however, in a comparison of the UVBR treatments, these variables showed no differences. In Ubatuba, where nutrient concentrations were significantly lower than those in Rimouski, light attenuation was less than that in Rimouski and UVBR

  17. Plant experiments with light-emitting diode module in Svet space greenhouse

    NASA Astrophysics Data System (ADS)

    Ilieva, Iliana; Ivanova, Tania; Naydenov, Yordan; Dandolov, Ivan; Stefanov, Detelin

    2010-10-01

    Light is necessary for photosynthesis and shoot orientation in the space plant growth facilities. Light modules (LM) must provide sufficient photosynthetic photon flux for optimal efficiency of photosynthetic processes and also meet the constraints for power, volume and mass. A new LM for Svet space greenhouse using Cree® XLamp® 7090 XR light-emitting diodes (LEDs) was developed. Monochromic LEDs emitting in the red, green, and blue regions of the spectrum were used. The LED-LM contains 36 LED spots - 30 LED spots with one red, green and blue LED and 6 LED spots with three red LEDs. Digital Multiplex Control Unit controls the LED spots and can set 231 levels of light intensity thus achieving Photosynthetic Photon Flux Density (PPFD) in the range 0-400 μmol m -2 s -1 and different percentages of the red, green and blue light, depending on the experimental objectives. Two one-month experiments with plants - lettuce and radicchio were carried out at 400 μmol m -2 s -1 PPFD (high light - HL) and 220 μmol m -2 s -1 PPFD (low light - LL) and 70% red, 20% green and 10% blue light composition. To evaluate the efficiency of photosynthesis, in vivo modulated chlorophyll fluorescence was measured by Pulse Amplitude Modulation (PAM) fluorometer on leaf discs and the following parameters: effective quantum yield of Photosystem II ( ΦPSII) and non-photochemical quenching (NPQ) were calculated. Both lettuce and radicchio plants grown at LL express higher photochemical activity of Photosystem II (PSII) than HL grown plants, evaluated by ΦPSII. Accelerated rise in NPQ in both LL grown plants was observed, while steady state NPQ values were higher in LL grown lettuce plants and did not differ in LL and HL grown radicchio plants. The extent of photoinhibition process in both plants was evaluated by changes in malonedialdehyde (MDA) concentration, peroxidase (POX) activity and hydrogen peroxide (H 2O 2) content. Accumulation of high levels of MDA and increased POX activity

  18. The new Seafloor Observatory (OBSEA) for remote and long-term coastal ecosystem monitoring.

    PubMed

    Aguzzi, Jacopo; Mànuel, Antoni; Condal, Fernando; Guillén, Jorge; Nogueras, Marc; del Rio, Joaquin; Costa, Corrado; Menesatti, Paolo; Puig, Pere; Sardà, Francesc; Toma, Daniel; Palanques, Albert

    2011-01-01

    A suitable sampling technology to identify species and to estimate population dynamics based on individual counts at different temporal levels in relation to habitat variations is increasingly important for fishery management and biodiversity studies. In the past two decades, as interest in exploring the oceans for valuable resources and in protecting these resources from overexploitation have grown, the number of cabled (permanent) submarine multiparametric platforms with video stations has increased. Prior to the development of seafloor observatories, the majority of autonomous stations were battery powered and stored data locally. The recently installed low-cost, multiparametric, expandable, cabled coastal Seafloor Observatory (OBSEA), located 4 km off of Vilanova i la Gertrú, Barcelona, at a depth of 20 m, is directly connected to a ground station by a telecommunication cable; thus, it is not affected by the limitations associated with previous observation technologies. OBSEA is part of the European Multidisciplinary Seafloor Observatory (EMSO) infrastructure, and its activities are included among the Network of Excellence of the European Seas Observatory NETwork (ESONET). OBSEA enables remote, long-term, and continuous surveys of the local ecosystem by acquiring synchronous multiparametric habitat data and bio-data with the following sensors: Conductivity-Temperature-Depth (CTD) sensors for salinity, temperature, and pressure; Acoustic Doppler Current Profilers (ADCP) for current speed and direction, including a turbidity meter and a fluorometer (for the determination of chlorophyll concentration); a hydrophone; a seismometer; and finally, a video camera for automated image analysis in relation to species classification and tracking. Images can be monitored in real time, and all data can be stored for future studies. In this article, the various components of OBSEA are described, including its hardware (the sensors and the network of marine and land nodes

  19. FerryMon: An Unattended Ferry-Based Observatory to Assess Human and Climatically- Induced Ecological Change in the Neuse River-Pamlico Sound System, North Carolina, USA

    NASA Astrophysics Data System (ADS)

    Guajardo, R.; Paerl, H. W.; Hall, N.; Whipple, A.; Luettich, R.

    2007-12-01

    In North Carolina's Neuse River Estuary (NRE)-Pamlico Sound (PS) System, nitrogen (N)-driven eutrophication, water quality and habitat decline have prompted the State and US EPA to mandate watershed-based N load reductions, including a total maximum daily allowable N load (TMDL). Chlorophyll a (chl-a), the indicator of algal biomass, is the measure for the efficacy of N reductions, with "acceptable" values being <40 μg chl- a L-1. However, algal blooms are patchy in time and space, making exceedances of 40 μ g L-1 difficult to track. The North Carolina ferry-based water quality monitoring program, FerryMon (www.ferrymon.org) addresses this and other environmental monitoring needs in the NRE-PS. FerryMon uses NC DOT ferries to provide continuous, space-time intensive, accurate measurements of chl-a and other key water quality criteria, using sensors placed in a flow-through system and discrete sampling of nutrients, organics, diagnostic photopigment and molecular indicators of major algal groups in a near real-time manner. Complementing FerryMon are automated vertical profilers (AVPs), which produce chl-a and other water quality indicator depth profiles with very high time and vertical resolution. In-line spectral fluorometers (Algae Online Analyzers (AOAs)) will be installed starting in late 2007, providing rapid early warning detection and quantification of algal blooms. FerryMon permits spatial characterization of trends in water quality conditions over a range of relevant physical, chemical and biological time scales. This enhanced capability is timely, given a protracted period of increased tropical storm and hurricane activity that, in combination with anthropogenic nutrient enrichment, affects water quality in unpredictable, yet significant ways. FerryMon also serves as a data source for calibrating and verifying remotely sensed indicators of water quality (photopigments, turbidity), nutrient-productivity and hydrologic modeling. Data management and

  20. BENCAL Cruise Report

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Barlow, Ray; Sessions, Heather; Silulwane, Nonkqubela; Engel, Hermann; Aiken, James; Fishwick, James; Martinez-Vicente, Victor; Morel, Andre

    2003-01-01

    a Fast Repetition Rate Fluorometer (FRRF) was deployed to acquire data on phytoplankton photosynthetic activity. Hydrographic profiling was conducted routinely during the cruise, and seawater samples were collected for measurements of salinity, oxygen, inorganic nutrients, pigments, particulate organic carbon, suspended particulate material, and primary production. Location of stations and times of optical deployments were selected to coincide with satellite overpasses whenever possible, and to cover a large range in trophic conditions.

  1. Using Multiple Watershed-scale Dye Tracing Tests to Study Water and Solute Transport in Naturally Obstructed Stream Channels

    NASA Astrophysics Data System (ADS)

    Jin, L.; Meeks, J. L.; Hubbard, K. A.; Kurian, L. M.; Siegel, D. I.; Lautz, L. K.; Otz, M. H.

    2007-12-01

    Temporary storage of surface water at channel sides and pools significantly affects water and solute transport downstream in watersheds. Beavers, natural "stream channel engineers", build dams which obstruct stream flow and temporarily store water in small to large ponds within stream channels. These ponds substantially delay water movement and increase the water residence time in the system. To study how water and solutes move through these obstructed stream channels, we did multiple dye tracing tests at Cherry Creek, a main tributary to Red Canyon Creek (Wind River Range, Wyoming). First we surveyed beaver dam distributions in detail within the study reaches. We then introduced dyes four times from July 2nd to 6th, 2007 using a scale-up approach. The observation site was fixed at the mouth of Cherry Creek, and 1.5 grams of Rhodamine WT (RWT) dye was injected sequentially at upstream sites with increasing test reach length. The reach lengths scaled up from 500m to 2.5 km. A field fluorometer recorded RWT concentrations every 15 seconds. The results show non-linear decreases of the peak concentration of the dye tracing cloud as the reach scaled up. Also, the times to 1.) the arrivals of the leading edges (Tl), 2.) the peak concentrations (Tp) and 3.) the tailing edges (Tt) and 4) the durations of the tracer cloud (Td) behaved non-linearly as function of length scale. For example, plots of arrivals of leading edges and tailing edges with scale distance appear to define curves of the form; Tl=27.665e1.07× Distance (r2=0.99) and Tt=162.62e0.8551× Distance (r2=0.99), respectively. The greatest non-linearity occurred for the time of tailing and the least for the time of leading edge. These observations are consistent with what would be expected with greater density of dams and/or storage volumes as the reach length increased upgradient. To come to a first approximation, we are currently modeling the breakthrough curves with the solute transport code OTIS to address

  2. High-Throughput Analysis of Enzyme Activities

    SciTech Connect

    Lu, Guoxin

    2007-01-01

    detection modes. The detection limits are 22, 15, and 3.6 μM ADP for using fluorometer, ICCD and PMT respectively. The Michealis constant K m(ATP) for protein kinases ranges from 5 to 100 μM. For inhibitor screening, in order to get the most accurate result, ATP concentration should be closed to Km. In this case, further lower the detection limit of ADP is needed before the direct detection of ADP can be actually used in kinase inhibitor screening.

  3. ROSE: development and demonstration of a "Mobile Response Observatory" prototype for subsea environmental monitoring.

    NASA Astrophysics Data System (ADS)

    Marvaldi, J.; Legrand, J.; Masset, J. F.

    2009-04-01

    parameter sensors. The prototype was fitted with the following ones : TRIOS EnviroFlu Hydrocarbon fluorometer; SBE 37-SMP microCAT CTD sensor; AANDERRA optode O2 sensor; WETLABS BBRTD-226R refractometer; RDI 300kHz ADCP profiler. Optical sensors requiring are protected against bio fouling by a process developed by Ifremer and based on chlorine generation on the sensor glass. The paper will present the design requirements and subsequent system specifications and experience return on: at sea operations and system behaviour on site; data acquisition by the various sensors and bio fouling protection efficiency; operation of the communication system and messenger system.

  4. Interactive Effects of Temperature and UV Radiation on Photosynthesis of Chlorella Strains from Polar, Temperate and Tropical Environments: Differential Impacts on Damage and Repair

    PubMed Central

    Wong, Chiew-Yen; Teoh, Ming-Li; Phang, Siew-Moi; Lim, Phaik-Eem; Beardall, John

    2015-01-01

    Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400–700 nm), PAR plus ultraviolet-A (320–400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280–320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain

  5. Controls on spatial variations in flow resistance along steep mountain streams

    NASA Astrophysics Data System (ADS)

    David, Gabrielle C. L.; Wohl, Ellen; Yochum, Steven E.; Bledsoe, Brian P.

    2010-03-01

    Detailed channel and water surface surveys were conducted on 15 mountain stream reaches (9 step-pool, 5 cascade, and 1 plane-bed) using a tripod-mounted Light Detection and Ranging scanner and laser theodolite. Reach-average velocities were measured at varying discharges with dye tracers and fluorometers. Multiple regressions and analysis of variance tests were used to test hypothesized correlations between Darcy-Weisbach friction coefficient, f, and potential control variables. Gradient (S0) and relative grain submergence (Rh/D84) individually explained a low proportion of the variability in f (R2 = 0.18), where Rh is hydraulic radius, D84 is the 84th percentile of the cumulative grain size distribution, and R2 is equal to the coefficient of determination. Because channel type, grain size, and S0 are interrelated, we tested the hypothesis that f is highly correlated with all three of these variables or a combination of the above variables with flow period (a categorical variable) or dimensionless unit discharge (q*). Total resistance correlated strongly (adj-R2 = 0.74, 0.69, and 0.64) with S0, flow period, wood load (volume of wood/m2 of channel), q*, and channel type (step-pool, cascade, plane-bed). Total resistance differed between step-pool and plane-bed and between cascade and plane-bed reaches. Significant differences in f in step-pool and cascade reaches were found at the same values of flow and S0. The regression analyses indicate that discharge explains the most variability in f, followed by S0 when discharge is similar among channel reaches, but that Rh/D84 is not an appropriate variable in these steep mountain streams to represent variations in both resistance and discharge. Results also indicate that the forms of resistance among channel types are sufficiently different to change the relationship of the control variables with f in each channel type. These results can be used to further the development of predictive equations for high-gradient mountain

  6. Unsaturated Zone Tracer Test at the Bemidji, Minnesota Crude Oil Spill Site

    NASA Astrophysics Data System (ADS)

    Herkelrath, W. N.; Delin, G. N.

    2003-12-01

    As a part of a study of the subsurface transport and natural attenuation of petroleum hydrocarbon contaminants at the Bemidji, Minnesota crude-oil spill research site, we used aqueous tracers to investigate solute transport from the soil surface through the crude oil-contaminated unsaturated zone to the water table. We applied tracer solution to the soil surface within a 5 by 12 meter tracer test plot that ran from a heavily oil-contaminated area to an oil-free zone. The depth to the water table was about 6 meters. The tracer test plot was instrumented with soil moisture probes, tensiometers, suction lysimeters, and drive-point sampling wells. Sixty liters of solution containing about 6.0E03 mg/l rhodamine WT and 1.0E04 mg/l bromide was uniformly sprayed on the soil surface in October 2001. We monitored subsequent tracer movement in response to precipitation by obtaining water samples weekly using the suction lysimeters in the unsaturated zone and the drive point wells in the saturated zone. Rhodamine concentrations were measured in the field using a fluorometer, and bromide concentrations were measured in the lab using ion chromatography. The time required for rhodamine tracer to reach the water table was 340 +/- 26 days. Travel times for bromide were about the same as for rhodamine, but the bromide data were less useful because the maximum bromide concentrations observed in the wells were close to background values. Rhodamine travel times through the oily unsaturated zone were not significantly different from the travel times through the oil-free unsaturated zone. However, the peak rhodamine concentrations found in ground-water samples obtained below the oil zone were an average of 3 times larger than the peak rhodamine values beneath the oil-free zone. We hypothesize that the rhodamine was adsorbed less in the oil-contaminated zone than in the oil-free zone because iron-containing minerals that absorb rhodamine have been largely removed from the oily sediments

  7. Attempting to link hydro-morphology, transient storage and metabolism in streams: Insights from reactive tracer experiments

    NASA Astrophysics Data System (ADS)

    Kurz, Marie J.; Schmidt, Christian; Blaen, Phillip; Knapp, Julia L. A.; Drummond, Jennifer D.; Martí, Eugenia; Zarnetske, Jay P.; Ward, Adam S.; Krause, Stefan

    2016-04-01

    In-stream transient storage zones, including the hyporheic zone and vegetation beds, can be hotspots of biogeochemical processing in streams, enhancing ecosystem functions such as metabolism and nutrient uptake. The spatio-temporal dynamics and reactivity of these storage zones are influenced by multiple factors, including channel geomorphology, substrate composition and hydrology, and by anthropogenic modifications to flow regimes and nutrient loads. Tracer injections are a commonly employed method to evaluate solute transport and transient storage in streams; however, reactive tracers are needed to differentiate between metabolically active and inactive transient storage zones. The reactive stream tracer resazurin (Raz), a weakly fluorescent dye which irreversibly transforms to resorufin (Rru) under mildly reducing conditions, provides a proxy for aerobic respiration and an estimate of the metabolic activity associated with transient storage zones. Across a range of lotic ecosystems, we try to assess the influence of stream channel hydro-morphology, morphologic heterogeneity, and substrate type on reach (103 m) and sub-reach (102 m) scale transient storage, respiration, and nutrient uptake. To do so, we coupled injections of Raz and conservative tracers (uranine and/or salt) at each study site. The study sites included: vegetated mesocosms controlled for water depth; vegetated and un-vegetated sediment-filled mesocosms fed by waste-water effluent; a contrasting sand- vs. gravel-bedded lowland stream (Q = 0.08 m3/s); and a series of upland streams with varying size (Q = 0.1 - 1.5 m3/s) and prevalence of morphologic features. Continuous time-series of tracer concentrations were recorded using in-situ fluorometers and EC loggers. At the stream sites, time-series were recorded at multiple downstream locations in order to resolve sub-reach dynamics. Analyses yielded highly variable transport metrics and Raz-Rru transformation between study sites and between sub

  8. The molecular cloning and clarification of a photorespiratory mutant, oscdm1, using enhancer trapping

    PubMed Central

    Wu, Jinxia; Zhang, Zhiguo; Zhang, Qian; Han, Xiao; Gu, Xiaofeng; Lu, Tiegang

    2015-01-01

    Enhancer trap systems have been demonstrated to increase the effectiveness of gene identification in rice. In this study, a chlorophyll-deficient mutant, named oscdm1, was screened and characterized in detail from a T-DNA enhancer-tagged population. The oscdm1 plants were different from other chlorophyll-deficient mutants; they produced chlorotic leaves at the third leaf stage, which gradually died with further growth of the plants. However, the oscdm1 plants were able to survive exposure to elevated CO2 levels, similar to photorespiratory mutants. An analysis of the T-DNA flanking sequence in the oscdm1 plants showed that the T-DNA was inserted into the promoter region of a serine hydroxymethyltransferase (SHMT) gene. OsSHMT1 is a key enzyme that is ubiquitous in nature and structurally conserved across kingdoms. The enzyme is responsible for the interconversion of serine and glycine and is essential for cellular one-carbon metabolism. Full-length OsSHMT1 complemented the oscdm1 phenotype, and the downregulation of OsSHMT1 in wild-type plants by RNA interference (RNAi) produced plants that mimicked the oscdm1 phenotype. GUS assays and quantitative PCR revealed the preferential expression of OsSHMT1 in young leaves. TEM revealed serious damage to the thylakoid membrane in oscdm1 chloroplasts. The oscdm1 plants showed more extensive damage than wild type using an IMAGING-PAM fluorometer, especially under high light intensities. OsSHMT1-GFP localized exclusively to mitochondria. Further analysis revealed that the H2O2 content in the oscdm1 plants was twice that in wild type at the fourth leaf stage. This suggests that the thylakoid membrane damage observed in the oscdm1 plants was caused by excessive H2O2. Interestingly, OsSHMT1-overexpressing plants exhibited increased photosynthetic efficiency and improved plant productivity. These results lay the foundation for further study of the OsSHMT1 gene and will help illuminate the functional role of OsSHMT1 in

  9. Phytoplankton-Fluorescence-Lifetime Vertical Profiler

    NASA Technical Reports Server (NTRS)

    Fernandez, Salvador M.; Guignon, Ernest F.; St. Louis, Ernest

    2004-01-01

    same principle as the one described in "Fluorometer for Analysis of Photosynthesis in Phytoplankton" (SSC-00110), NASA Tech Briefs, Vol. 24, No. 1 (November 2000), page 79. The excitation is modulated at a frequency of 70 MHz, and the phase shift between the excitation light and the emitted fluorescence is measured by a detection method in which the 70 MHz signal is down-converted to a 400 Hz signal. The fluorescence lifetime can be computed from the known relationship among the fluorescence lifetime, phase shift, and modulation frequency

  10. Rapid effects of diverse toxic water pollutants on chlorophyll a fluorescence: variable responses among freshwater microalgae.

    PubMed

    Choi, Chang Jae; Berges, John A; Young, Erica B

    2012-05-15

    Chlorophyll a fluorescence of microalgae is a compelling indicator of toxicity of dissolved water contaminants, because it is easily measured and responds rapidly. While different chl a fluorescence parameters have been examined, most studies have focused on single species and/or a narrow range of toxins. We assessed the utility of one chl a fluorescence parameter, the maximum quantum yield of PSII (F(v)/F(m)), for detecting effects of nine environmental pollutants from a range of toxin classes on 5 commonly found freshwater algal species, as well as the USEPA model species, Pseudokirchneriella subcapitata. F(v)/F(m) declined rapidly over <20 min in response to low concentrations of photosynthesis-specific herbicides Diuron(®) and metribuzin (both <40 nM), atrazine (<460 nM) and terbuthylazine (<400 nM). However, F(v)/F(m) also responded rapidly and in a dose-dependent way to toxins glyphosate (<90 μM), and KCN (<1 mM) which have modes of action not specific to photosynthesis. F(v)/F(m) was insensitive to 30-40 μM insecticides methyl parathion, carbofuran and malathion. Algal species varied in their sensitivity to toxins. No single species was the most sensitive to all nine toxins, but for six toxins to which algal F(v)/F(m) responded significantly, the model species P. subcapitata was less sensitive than other taxa. In terms of suppression of F(v)/F(m) within 80 min, patterns of concentration-dependence differed among toxins; most showed Michaelis-Menten saturation kinetics, with half-saturation constant (K(m)) values for the PSII inhibitors ranging from 0.14 μM for Diuron(®) to 6.6 μM for terbuthylazine, compared with a K(m) of 330 μM for KCN. Percent suppression of F(v)/F(m) by glyphosate increased exponentially with concentration. F(v)/F(m) provides a sensitive and easily-measured parameter for rapid and cost-effective detection of effects of many dissolved toxins. Field-portable fluorometers will facilitate field testing, however distinct responses

  11. Are lichens active under snow in continental Antarctica?

    PubMed

    Pannewitz, Stefan; Schlensog, Mark; Green, T G Allan; Sancho, Leopoldo G; Schroeter, Burkhard

    2003-03-01

    Photosynthetic activity, detected as chlorophyll a fluorescence, was measured for lichens under undisturbed snow in continental Antarctica using fibre optics. The fibre optics had been buried by winter snowfall after being put in place the previous year under snow-free conditions. The fibre optics were fixed in place using specially designed holding devices so that the fibre ends were in close proximity to selected lichens. Several temperature and PPFD (photosynthetic photon flux density) sensors were also installed in or close to the lichens. By attaching a chlorophyll a fluorometer to the previously placed fibre optics it proved possible to measure in vivo potential photosynthetic activity of continental Antarctic lichens under undisturbed snow. The snow cover proved to be a very good insulator for the mosses and lichens but, in contrast to the situation reported for the maritime Antarctic, it retained the severe cold of the winter and prevented early warming. Therefore, the lichens and mosses under snow were kept inactive at subzero temperatures for a prolonged time, even though the external ambient air temperatures would have allowed metabolic activity. The results suggest that the major activity period of the lichens was at the time of final disappearance of the snow and lasted about 10-14 days. The activation of lichens under snow by high air humidity appeared to be very variable and species specific. Xanthoria mawsonii was activated at temperatures below -10 degrees C through absorption of water from high air humidity. Physcia dubia showed some activation at temperatures around -5 degrees C but only became fully activated at thallus temperatures of 0 degrees C through liquid water. Candelariella flava stayed inactive until thallus temperatures close to zero indicated that liquid water had become available. Although the snow cover represented the major water supply for the lichens, lichens only became active for a brief time at or close to the time the snow

  12. Intrinsically photosensitive retinal ganglion cell function in relation to age: A pupillometric study in humans with special reference to the age-related optic properties of the lens

    PubMed Central

    2012-01-01

    Background The activity of melanopsin containing intrinsically photosensitive ganglion retinal cells (ipRGC) can be assessed by a means of pupil responses to bright blue (appr.480 nm) light. Due to age related factors in the eye, particularly, structural changes of the lens, less light reaches retina. The aim of this study was to examine how age and in vivo measured lens transmission of blue light might affect pupil light responses, in particular, mediated by the ipRGC. Methods Consensual pupil responses were explored in 44 healthy subjects aged between 26 and 68 years. A pupil response was recorded to a continuous 20 s light stimulus of 660 nm (red) or 470 nm (blue) both at 300 cd/m2 intensity (14.9 and 14.8 log photons/cm2/s, respectively). Additional recordings were performed using four 470 nm stimulus intensities of 3, 30, 100 and 300 cd/m2. The baseline pupil size was measured in darkness and results were adjusted for the baseline pupil and gender. The main outcome parameters were maximal and sustained pupil contraction amplitudes and the postillumination response assessed as area under the curve (AUC) over two time-windows: early (0–10 s after light termination) and late (10–30 s after light termination). Lens transmission was measured with an ocular fluorometer. Results The sustained pupil contraction and the early poststimulus AUC correlated positively with age (p = 0.02, p = 0.0014, respectively) for the blue light stimulus condition only. The maximal pupil contraction amplitude did not correlate to age either for bright blue or red light stimulus conditions. Lens transmission decreased linearly with age (p < 0.0001). The pupil response was stable or increased with decreasing transmission, though only significantly for the early poststimulus AUC to 300 cd/m2 light (p = 0.02). Conclusions Age did not reduce, but rather enhance pupil responses mediated by ipRGC. The age related decrease of blue light transmission led

  13. UV-C tolerance of symbiotic Trebouxia sp. in the space-tested lichen species Rhizocarpon geographicum and Circinaria gyrosa: role of the hydration state and cortex/screening substances

    NASA Astrophysics Data System (ADS)

    Sánchez, Francisco Javier; Meeßen, Joachim; del Carmen Ruiz, M.; Sancho, Leopoldo G.; Ott, Sieglinde; Vílchez, Carlos; Horneck, Gerda; Sadowsky, Andres; de la Torre, Rosa

    2014-01-01

    Many experiments were carried out in order to evaluate the survival capacity of extremotolerant lichens when facing harsh conditions, including those of outer space or of simulated Martian environment. For further progress, a deeper study on the physiological mechanisms is needed that confer the unexpected levels of resistance detected on these symbiotic organisms. In this work, the response of the lichenized green algae Trebouxia sp. (a predominant lichen photobiont) to increasing doses of UV-C radiation is studied. UV-C (one of the most lethal factors to be found in space together with vacuum and cosmic-ionizing radiation with high atomic number and energy (HZE) particles) has been applied in the present experiments up to a maximum dose analogue to 67 days in Low Earth Orbit (LEO). For that purpose we selected two extremotolerant and space-tested lichen species in which Trebouxia sp. is the photosynthetic partner: the crustose lichen Rhizocarpon geographicum and the fruticose lichen Circinaria gyrosa. In order to evaluate the effect of the physiological state of the lichen thallus (active when wet and dormant when dry) and of protective structures (cortex and photoprotective pigments) on the resistance of the photobiont to UV-C, four different experimental conditions were tested: (1) dry intact samples, (2) wet intact samples, (3) dry samples without cortex/acetone-rinsed and (4) wet samples without cortex/acetone-rinsed. After irradiation and a 72 hours period of recovery, the influence of UV-C on the two lichen's photobiont under each experimental approach was assessed by two complimentary methods: (1) By determining the photosystem II (PSII) activity in three successive 24 hours intervals (Mini-PAM fluorometer) to investigate the overall state of the photosynthetic process and the resilience of Trebouxia sp. (2) By performing high performance liquid chromatography (HPLC)-quantification of four essential photosynthetic pigments (chlorophyll a, chlorophyll b,

  14. Fisetin Protects PC12 Cells from Tunicamycin-Mediated Cell Death via Reactive Oxygen Species Scavenging and Modulation of Nrf2-Driven Gene Expression, SIRT1 and MAPK Signaling in PC12 Cells.

    PubMed

    Yen, Jui-Hung; Wu, Pei-Shan; Chen, Shu-Fen; Wu, Ming-Jiuan

    2017-04-17

    Fisetin (3,7,3',4'-tetrahydroxyflavone) is a dietary flavonol and exhibits antioxidant, anti-inflammatory, and neuroprotective activities. However, high concentration of fisetin is reported to produce reactive oxygen species (ROS), induce endoplasmic reticulum (ER) stress and cause cytotoxicity in cancer cells. The aim of this study is to investigate the cytoprotective effects of low concentration of fisetin against tunicamycin (Tm)-mediated cytotoxicity in neuronal-like catecholaminergic PC12 cells. Cell viability was assayed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptotic and autophagic markers were analyzed by Western blot. Gene expression of unfolded protein response (UPR) and Phase II enzymes was further investigated using RT-Q-PCR or Western blotting. Intracellular ROS level was measured using 2',7'-dichlorodihydrofluorescein diacetate (H₂DCFDA) by a fluorometer. The effects of fisetin on mitogen activated protein kinases (MAPKs) and SIRT1 (Sirtuin 1) signaling pathways were examined using Western blotting and specific inhibitors. Fisetin (<20 µM) restored cell viability and repressed apoptosis, autophagy and ROS production in Tm-treated cells. Fisetin attenuated Tm-mediated expression of ER stress genes, such as glucose-regulated proteins 78 (GRP78), C/EBP homologous protein (CHOP also known as GADD153) and Tribbles homolog 3 (TRB3), but induced the expression of nuclear E2 related factor (Nrf)2-targeted heme oxygenase (HO)-1, glutamate cysteine ligase (GCL) and cystine/glutamate transporter (xCT/SLC7A11), in both the presence and absence of Tm. Moreover, fisetin enhanced phosphorylation of ERK (extracellular signal-regulated kinase), JNK (c-JUN NH₂-terminal protein kinase), and p38 MAPK. Addition of JNK and p38 MAPK inhibitor significantly antagonized its cytoprotective activity and modulatory effects on UPR. Fisetin also restored Tm-inhibited SIRT1 expression and addition of sirtinol (SIRT1 activation inhibitor

  15. NASA Tech Briefs, December 2007

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Topics include: Ka-Band TWT High-Efficiency Power Combiner for High-Rate Data Transmission; Reusable, Extensible High-Level Data-Distribution Concept; Processing Satellite Imagery To Detect Waste Tire Piles; Monitoring by Use of Clusters of Sensor-Data Vectors; Circuit and Method for Communication Over DC Power Line; Switched Band-Pass Filters for Adaptive Transceivers; Noncoherent DTTLs for Symbol Synchronization; High-Voltage Power Supply With Fast Rise and Fall Times; Waveguide Calibrator for Multi-Element Probe Calibration; Four-Way Ka-Band Power Combiner; Loss-of-Control-Inhibitor Systems for Aircraft; Improved Underwater Excitation-Emission Matrix Fluorometer; Metrology Camera System Using Two-Color Interferometry; Design and Fabrication of High-Efficiency CMOS/CCD Imagers; Foam Core Shielding for Spacecraft CHEM-Based Self-Deploying Planetary Storage Tanks Sequestration of Single-Walled Carbon Nanotubes in a Polymer PPC750 Performance Monitor Application-Program-Installer Builder Using Visual Odometry to Estimate Position and Attitude Design and Data Management System Simple, Script-Based Science Processing Archive Automated Rocket Propulsion Test Management Online Remote Sensing Interface Fusing Image Data for Calculating Position of an Object Implementation of a Point Algorithm for Real-Time Convex Optimization Handling Input and Output for COAMPS Modeling and Grid Generation of Iced Airfoils Automated Identification of Nucleotide Sequences Balloon Design Software Rocket Science 101 Interactive Educational Program Creep Forming of Carbon-Reinforced Ceramic-Matrix Composites Dog-Bone Horns for Piezoelectric Ultrasonic/Sonic Actuators Benchtop Detection of Proteins Recombinant Collagenlike Proteins Remote Sensing of Parasitic Nematodes in Plants Direct Coupling From WGM Resonator Disks to Photodetectors Using Digital Radiography To Image Liquid Nitrogen in Voids Multiple-Parameter, Low-False-Alarm Fire-Detection Systems Mosaic-Detector-Based Fluorescence

  16. Chlorophyll fluorescence tracks seasonal variations of photosynthesis from leaf to canopy in a temperate forest.

    PubMed

    Yang, Hualei; Yang, Xi; Zhang, Yongguang; Heskel, Mary A; Lu, Xiaoliang; Munger, J William; Sun, Shucun; Tang, Jianwu

    2016-12-14

    Accurate estimation of terrestrial gross primary productivity (GPP) remains a challenge despite its importance in the global carbon cycle. Chlorophyll fluorescence (ChlF) has been recently adopted to understand photosynthesis and its response to the environment, particularly with remote sensing data. However, it remains unclear how ChlF and photosynthesis are linked at different spatial scales across the growing season. We examined seasonal relationships between ChlF and photosynthesis at the leaf, canopy, and ecosystem scales and explored how leaf-level ChlF was linked with canopy-scale solar-induced chlorophyll fluorescence (SIF) in a temperate deciduous forest at Harvard Forest, Massachusetts, USA. Our results show that ChlF captured the seasonal variations of photosynthesis with significant linear relationships between ChlF and photosynthesis across the growing season over different spatial scales (R(2 ) = 0.73, 0.77, and 0.86 at leaf, canopy, and satellite scales, respectively; P < 0.0001). We developed a model to estimate GPP from the tower-based measurement of SIF and leaf-level ChlF parameters. The estimation of GPP from this model agreed well with flux tower observations of GPP (R(2 ) = 0.68; P < 0.0001), demonstrating the potential of SIF for modeling GPP. At the leaf scale, we found that leaf Fq '/Fm ', the fraction of absorbed photons that are used for photochemistry for a light-adapted measurement from a pulse amplitude modulation fluorometer, was the best leaf fluorescence parameter to correlate with canopy SIF yield (SIF/APAR, R(2 ) = 0.79; P < 0.0001). We also found that canopy SIF and SIF-derived GPP (GPPSIF ) were strongly correlated to leaf-level biochemistry and canopy structure, including chlorophyll content (R(2 ) = 0.65 for canopy GPPSIF and chlorophyll content; P < 0.0001), leaf area index (LAI) (R(2 ) = 0.35 for canopy GPPSIF and LAI; P < 0.0001), and normalized difference vegetation index (NDVI) (R(2 ) = 0.36 for

  17. [MODIS Investigation

    NASA Technical Reports Server (NTRS)

    Abbott, Mark R.

    1998-01-01

    The objective of the last six months were: (1) Continue analysis of Hawaii Ocean Time-series (HOT) bio-optical mooring data, and Southern Ocean bio-optical drifter data; (2) Complete development of documentation of MOCEAN algorithms and software for use by MOCEAN team and GLI team; (3) Deploy instrumentation during JGOFS cruises in the Southern Ocean; (4) Participate in test cruise for Fast Repetition Rate (FRR) fluorometer; (5) Continue chemostat experiments on the relationship of fluorescence quantum yield to environmental factors; and (6) Continue to develop and expand browser-based information system for in situ bio-optical data. We are continuing to analyze bio-optical data collected at the Hawaii Ocean Time Series mooring as well as data from bio-optical drifters that were deployed in the Southern Ocean. A draft manuscript has now been prepared and is being revised. A second manuscript is also in preparation that explores the vector wind fields derived from NSCAT measurements. The HOT bio-optical mooring was recovered in December 1997. After retrieving the data, the sensor package was serviced and redeployed. We have begun preliminary analysis of these data, but we have only had the data for 3 weeks. However, all of the data were recovered, and there were no obvious anomalies. We will add second sensor package to the mooring when it is serviced next spring. In addition, Ricardo Letelier is funded as part of the SeaWiFS calibration/validation effort (through a subcontract from the University of Hawaii, Dr. John Porter), and he will be collecting bio-optical and fluorescence data as part of the HOT activity. This will provide additional in situ measurements for MODIS validation. As noted in the previous quarterly report, we have been analyzing data from three bio-optical drifters that were deployed in the Southern Ocean in September 1996. We presented results on chlorophyll and drifter speed. For the 1998 Ocean Sciences meeting, a paper will be presented on

  18. The effects of CO2 on phytoplankton community structure in the Amazon River Plume

    NASA Astrophysics Data System (ADS)

    Chen, T. L.; Goes, J. I.; Gomes, H. R.; McKee, K. T.

    2013-12-01

    The Amazon River Plume results from an enormous discharge of freshwater and organic matter into the Atlantic Ocean. It is a unique environment with a natural pCO2 gradient in the surface waters of the plume that range from 130-950 μatm. The response of coastal marine phytoplankton to increased anthropogenic CO2 emission is still unknown, hence the Amazon River Plume gradient can serve as a natural laboratory to examine the potential influence of atmospheric CO2 increases and ocean acidification on phytoplankton community composition. A two pronged study was undertaken: the first in which shipboard samples from a 2010 cruise to the Amazon River Plume were analyzed to examine the distribution of 3 major phytoplankton groups (diatoms, diatom-diazotroph associations [DDAs], and the diazotroph Trichodesmium spp.) with respect to the natural pCO2 gradient; the second in which the growth response of Thalassiosira weisflogii, a representative diatom species, was examined under experimentally manipulated CO2 conditions. Cruise data analysis showed that diatoms were found with higher cell counts around 150 μatm; DDAs seemed to dominate waters within the narrow range of 350-400 μatm CO2; and the diazotroph Trichodesmium spp. grew in a wide range of pCO2 conditions, but with higher cell counts at upwards of 500 μatm. Phytoplankton group distributions along the CO2 gradient may be due to differences in their carbon-concentrating mechanism (CCMs) efficiencies. The CO2 manipulation apparatus was assembled such that the cells were grown under three different CO2 environments. Differential growth of T. weisflogii was observed at 150, 400, and 800 ppm CO2 treatment. T. weisflogii grew at all three CO2 concentrations, reflecting diatoms' physiological flexibility and efficient CCMs. Absorption spectra analysis of pigments and Fast Repetition Rate Fluorometer analysis indicate potential changes in photosynthetic machinery with different CO2 treatments. Future CO2 manipulation

  19. Chemical imaging and spectroscopy using tunable filters: Instrumentation, methodology, and multivariate analysis

    NASA Astrophysics Data System (ADS)

    Turner, John Frederick, II

    Spectral imaging has experienced tremendous growth during the past ten years and is rapidly becoming a formidable analytical tool. Recent advances in electronically tunable filters and array detectors are enabling high resolution spectral images to be acquired of chemical and biological systems that have traditionally been difficult to study non-invasively. Additionally, the development of powerful and inexpensive computer platforms is broadening the appeal of spectral imaging methods which have historically required costly and computationally adept computer workstations. The emphasis of my research has been to explore high throughput widefield imaging instrumentation and methodology using novel acousto-optic tunable filter (AOTF) and liquid crystal tunable filter (LCTF) imaging spectrometers. In order to demonstrate the feasibility of employing multiplexed AOTFs for spectroscopy and chemical imaging applications, a near- infrared (NIR) multiplexed AOTF spectrometer employing Hadamard encoding sequences has been developed. In addition, the use of multiplexed AOTFs as adaptive filters in NIR spectroscopy and fluorescence imaging has been demonstrated. A second type of electronically tunable image filter, the liquid crystal tunable filter (LCTF) has recently been developed and is well suited to high resolution, diffraction limited imaging applications. The earliest generation of LCTFs was based on the Lyot birefringent filter and possessed small transmittances due to the use of multiple polarizers and imperfect waveplate action. An improved LCTF prototype incorporating split-element Lyot filter stages has been evaluated and compared to the earlier generation of LCTF devices. The high image fidelity, wide acceptance angle, and large clear aperture of the LCTF make it well suited to macroscopic chemical imaging applications. A macroscopic imaging fluorometer employing LCTFs for source tuning and emission filtering has been developed for high throughput microtiter plate

  20. The Prospects for Using Little Diomede Island as a Base for Monitoring Bering Strait

    NASA Astrophysics Data System (ADS)

    Cooper, L. W.; Kelly, V.; Codispoti, L. A.; Sheffield, G.; Grebmeier, J. M.

    2002-12-01

    Diomede, Alaska is arguably the most isolated community in the United States, located on a small island in the center of Bering Strait, one mile from the international dateline, where nutrient-rich waters from the Bering Sea enter the Arctic Ocean. Postal service is once weekly via helicopter, weather permitting and the 140 Native Inupiat residents (2000 census) are highly dependent upon a subsistence lifestyle utilizing local seabirds, marine mammals, and shellfish. Since the summer of 2000, we have worked with the local community to improve analytical capabilities to analyze waters flowing through the Bering Strait. Other goals of the Bering Strait Environmental Observatory include evaluating the biological health and contaminant burdens of marine mammals used for subsistence by island residents. We have also been annually using the Canadian Coast Guard Service Sir Wilfrid Laurier to assess the biological productivity of benthic organisms that are important as food sources in the Bering Strait region for apex predators such as bearded seal, walrus, diving ducks and gray whale. Future infrastructure that is needed includes a subsea water intake system that would be less vulnerable to wave and ice damage than the interim systems we have employed to date. Using a jet well pump in August, 2001, we pumped water onshore through a thermosalinograph, automated nutrient monitoring devices, a fluorometer, and we also collected discrete samples for silica and oxyen-18/oxygen-16 ratios in a small laboratory constructed under the village school. Results indicate that there is a strong relationship between the surface wind regime and the fertility of waters flowing through the center of Bering Strait. Following sustained northerly wind events, and an approximate 72 hour lag period, waters passing Little Diomede Island were predominantly of Alaska Coastal Water origin, with low nutrients and salinity, and comparatively high temperatures. Southerly winds were by contrast

  1. In situ spectral measurements improve the efficiency of light use efficiency models to estimate gross primary productivity in Mediterranean cork oak woodland

    NASA Astrophysics Data System (ADS)

    Cerasoli, S.; Silva, J. M.; Carvalhais, N.; Correia, A.; Costa e Silva, F.; Pereira, J. S.

    2013-12-01

    monthly basis, always around noon, on clear days. At the same time, under canopy PAR was measured by a ceptometer (AccuPAR LP-80, Decagon) and the quantum efficiency of PSII of cork oak leaves was measured by a pulse-modulated fluorometer (miniPAM, Walz). The temporal series of NDVI and PRI were different among the three PFT as well as their relationship with biophysical properties of vegetation. Being the largest intra- and inter-annual variability observed in the herbaceous layer. The spectral indexes were integrated into a LUE model and GPP estimates were performed optimizing individual parameters for each PFT. The cover fraction and varying tower footprints were used to calculate the contribution of each PFT to the overall GPP. The evaluation of the PFT-disaggregated optimization against eddy covariance measurements revealed an increase in the model efficiency when compared with lumped GPP estimates using MODIS spectral data.

  2. Fine-scale spatial and temporal plankton distributions in the Southern California Bight: lessons from in situ microscopes and broadband echosounders

    NASA Astrophysics Data System (ADS)

    Briseno-Avena, Christian

    Phytoplankton and zooplankton are important components of marine ecosystems, and play a major role in the biological pump, affecting carbon transport in the global oceans. Their dynamic heterogeneous spatial and temporal distributions require special tools for observing them at the ecological scales relevant to the individual organisms. In this work, I used optic and acoustic methods to study plankton organisms at spatial scales of meters and temporal scales ranging from minutes to months. Using two in situ microscopes I described the fine-scale vertical distribution of phytoplankton and several zooplankton taxa in a coastal location in the Southern California Bight. Highly resolved spatial observations revealed cryptic maxima of fluorescent particles not observed with traditional fluorometers. Furthermore, this high sampling resolution revealed that water density, and not depth, regulated the vertical position, and interactions between observed phytoplankton and zooplankton distributions. Underwater acoustic echosounders can be powerful tools to observe in situ plankton distributions. Interpreting the acoustic echoes, however, requires highly calibrated instruments and ground-truthing experiments to identify the source of acoustic signals. This work presents the description of a novel combination of a broadband, high-frequency (1.5-2.5 MHz) echosounder and a stereoscopic camera --combined, these systems can localize the echo produced by an individual target while simultaneously providing visual identification of the target. This work has provided one of the first comparisons of in situ measured broadband target strength (BTS) and the expected signal using a physical model. The results of this experiment revealed unexpected, important differences between measured and modeled BTS. This system was also used to make in situ observations of individual fragile gelatinous organisms, marine snow particles and phytoplankton, providing evidence of their significant acoustic

  3. Physical and biogeochemical observations of the Ross Sea polynya using Seagliders during the 2010-2011 austral spring

    NASA Astrophysics Data System (ADS)

    Queste, B. Y.; Smith, W. O., Jr.; Asper, V. L.; Lee, C. M.; Dinniman, M. S.; Gobat, J. I.; Heywood, K. J.

    2012-04-01

    The Antarctic is critical in regulating the global marine carbon cycle through its interactions with the atmosphere and its export of deep water. In particular, the Ross Sea is known to be one of the most productive regions of the Southern Ocean, partly due to the persistent large areas of open water, or polynyas, present there. It has been suggested that it is responsible for 28% of the total flux of atmospheric CO2 and thus has a dominant role in global carbon sequestration. The polynyas remain largely under-sampled due to the challenges caused by sea-ice and weather conditions. From November 2010 to February 2011, two Seagliders were deployed in the Ross polynya to observe the initiation and evolution of the spring bloom. Seagliders were a novel and effective tool to bypass the sampling difficulties at a fraction of the cost and inconvenience. Equipped with fluorometers, oxygen sensors, CTDs, and the ability to estimate current speeds, the gliders were able to obtain data in the polynya before access was possible by oceanographic vessels. Observations were also obtained along a 40 km transect under pack ice and during a 2 day excursion under the ice shelf. We present observations of phytoplankton dynamics, export of organic matter and related fluctuations in dissolved oxygen concentrations during the spring bloom in the polynya. A bloom was first observed at the end of November in the McMurdo polynya whilst a much larger diatom bloom began the second week of December in the Ross polynya. A second bloom then started the second week of January with a different planktonic composition at the same location. A small decrease in dissolved oxygen saturation was present as this organic matter was exported. Alongside these data, we show hydrographic sections under the sea ice and the ice shelf. Oceanographic features identified by the Seagliders include mesoscale fronts and eddies. A thermocline formed gradually deepening to about 50m as the sea-ice melted. Strong

  4. Challenges and Early Results: Interactive benthic experiments in hydrate environments of Barkley Canyon, NEPTUNE Canada.

    NASA Astrophysics Data System (ADS)

    Best, M.; Thomsen, L.; de Beer, D.

    2012-04-01

    NEPTUNE Canada, operating and online since 2009, is an 800km, 5-node, regional cabled ocean network across the northern Juan de Fuca Plate, northeastern Pacific, part of the Ocean Networks Canada Observatory. One of 15 study areas is an environment of exposed hydrate mounds along the wall of Barkley Canyon, at ~865m water depth. This is the home of a benthic crawler developed by Jacobs University of Germany, who is affectionately known as Wally. Wally is equipped with a range of sensors including a camera, methane sensor, current meter, fluorometer, turbidity meter, CTD, and a sediment microprofiler developed at the Max Planck Institute with probes for oxygen, methane, sulphide, pH, temperature, and conductivity. In conjunction with this sensor suite, a series of experiments have been designed to assess the cycling of biogenic carbon and carbonate in this complex environment. The biota range from microbes, to molluscs, to large fish, and therefore the carbon inputs include both a range of organic carbon compounds as well as the complex materials that are "biogenic carbonate". Controlled experimental specimens were deployed of biogenic carbonate (Mytilus edulis fresh shells) and cellulose (pieces of untreated pine lumber) that had been previously well characterized (photographed, weighed, and numbered, matching valves and lumber kept as controls). Deployment at the sediment/water interface was in such a way to maximize natural burial exhumation cycles but to minimize specimen interaction. 10 replicate specimens of each material were deployed in two treatments: 1) adjacent to a natural life and death assemblage of chemosynthetic bivalves and exposed hydrate on a hydrate mound and 2) on the muddy seafloor at a distance from the mound. In order to quantify and track the rates and processes of modification of the natural materials, and their possible environmental/ecological correlates, observations of the experimental specimens are being made on a regular basis using

  5. Deep Sea Shell Taphonomy: Interactive benthic experiments in hydrate environments of Barkley Canyon, Ocean Networks Canada.

    NASA Astrophysics Data System (ADS)

    Best, Mairi; Purser, Autun

    2015-04-01

    In order to quantify and track the rates and processes of modification of biogenic carbonate in gas hydrate environments, and their possible environmental/ecological correlates, ongoing observations of experimentally deployed specimens are being made using a remotely controlled crawler with camera and sensors. The crawler is connected to NEPTUNE Canada, an 800km, 5-node, regional cabled ocean network across the northern Juan de Fuca Plate, northeastern Pacific, part of Ocean Networks Canada. One of 15 study areas is an environment of exposed hydrate mounds along the wall of Barkley Canyon, at ˜865m water depth. This is the home of a benthic crawler developed by Jacobs University of Germany, who is affectionately known as Wally. Wally is equipped with a range of sensors including cameras, methane sensor, current meter, fluorometer, turbidity meter, CTD, and a sediment microprofiler with probes for oxygen, methane, sulphide, pH, temperature, and conductivity. In conjunction with this sensor suite, a series of experiments have been designed to assess the cycling of biogenic carbon and carbonate in this complex environment. The biota range from microbes, to molluscs, to large fish, and therefore the carbon inputs include both a range of organic carbon compounds as well as the complex materials that are "biogenic carbonate". Controlled experimental specimens were deployed of biogenic carbonate (Mytilus edulis fresh shells) and cellulose (pieces of untreated pine lumber) that had been previously well characterized (photographed, weighed, and numbered, matching valves and lumber kept as controls). Deployment at the sediment/water interface was in such a way to maximize natural burial exhumation cycles but to minimize specimen interaction. 10 replicate specimens of each material were deployed in two treatments: 1) adjacent to a natural life and death assemblage of chemosynthetic bivalves and exposed hydrate on a hydrate mound and 2) on the muddy seafloor at a distance

  6. Assessment of Heat Resistance of Bacterial Spores from Food Product Isolates by Fluorescence Monitoring of Dipicolinic Acid Release

    PubMed Central

    Kort, Remco; O'Brien, Andrea C.; van Stokkum, Ivo H. M.; Oomes, Suus J. C. M.; Crielaard, Wim; Hellingwerf, Klaas J.; Brul, Stanley

    2005-01-01

    This study is aimed at the development and application of a convenient and rapid optical assay to monitor the wet-heat resistance of bacterial endospores occurring in food samples. We tested the feasibility of measuring the release of the abundant spore component dipicolinic acid (DPA) as a probe for heat inactivation. Spores were isolated from the laboratory type strain Bacillus subtilis 168 and from two food product isolates, Bacillus subtilis A163 and Bacillus sporothermodurans IC4. Spores from the lab strain appeared much less heat resistant than those from the two food product isolates. The decimal reduction times (D values) for spores from strains 168, A163, and IC4 recovered on Trypticase soy agar were 1.4, 0.7, and 0.3 min at 105°C, 120°C, and 131°C, respectively. The estimated Z values were 6.3°C, 6.1°C, and 9.7°C, respectively. The extent of DPA release from the three spore crops was monitored as a function of incubation time and temperature. DPA concentrations were determined by measuring the emission at 545 nm of the fluorescent terbium-DPA complex in a microtiter plate fluorometer. We defined spore heat resistance as the critical DPA release temperature (Tc), the temperature at which half the DPA content has been released within a fixed incubation time. We found Tc values for spores from Bacillus strains 168, A163, and IC4 of 108°C, 121°C, and 131°C, respectively. On the basis of these observations, we developed a quantitative model that describes the time and temperature dependence of the experimentally determined extent of DPA release and spore inactivation. The model predicts a DPA release rate profile for each inactivated spore. In addition, it uncovers remarkable differences in the values for the temperature dependence parameters for the rate of spore inactivation, DPA release duration, and DPA release delay. PMID:16000762

  7. Effects of Solar Radiation on the Patagonian Rhodophyte Corallina officinatis (L.).

    PubMed

    Häder, Donat-P; Lebert, Michael; Walter Helbling, E

    2003-01-01

    Experiments were conducted in Patagonian waters (Argentina) to assess the impact of solar radiation (PAR, 400-700 nm, and UVR, 280-400 nm) upon two strains of the red alga Corallina officinalis Linnaeus, characteristic of the mid and lower intertidal zone, during March 2000. Fluorescence parameters were determined using a pulse amplitude modulated (PAM) fluorometer. The two strains had different initial optimal quantum yields but similar strong decreases in the quantum yield when the algae were exposed to short-term solar radiation and similar recovery characteristics in dim light. The quantum yield had the lowest values at noon, but it increased in the afternoon / evening hours, when irradiances were lower. PAR (irradiance at noon about 500 W m(-2)) was responsible for most of the decrease in the yield ( approximately 50%) on clear days, with UVR accounting for a significant increment. However, on cloudy days the UVR component caused an even more pronounced decrease. In their natural environment, specimens in the shade had a higher effective quantum yield than in sun-lit areas. Fluence rate response curves indicated that thalli from the mid intertidal had a pronounced nonphotochemical quenching at intermediate and higher irradiances; however, this was not observed in the thalli from the lower intertidal. Fast induction and relaxation kinetics showed obvious differences between the two strains, but also demonstrated a rapid adaptation of the species to the changing light conditions as well as a fast decrease of PS II fluorescence upon exposure to solar radiation. All photosynthetic pigments were bleached during exposure to solar radiation over a full day. Strong absorption in the UV-A range, most likely due to mycosporine like amino acids, was determined in both strains. The study of the differential sensitivity to solar radiation and recovery capacity of these Corallina strains, as well as the presence of protective compounds, suggests that a combination of

  8. Effect of iron limitation on photosynthesis in a marine diatom

    SciTech Connect

    Greene, R.M.; Falkowski, P.G. ); Geider, R.J. )

    1991-12-01

    The response of the marine diatom Phaeodactylum tricornutum to Fe deficiency was evaluated in the context of fundamental physiological models of growth and photosynthesis. Fe deficiency induced chlorosis, which decreased Chl a:C ratios and Chl a-specific light-saturated photosynthesis (P{sub m}{sup B}). In contrast to P{sub m}{sup B}, {alpha}{sup B} was slightly increased under Fe deficiency, and photosynthesis in Fe-deficient cells became light-saturated at lower irradiances than in Fe-replete cells grown at the same irradiance. Fe deficiency increased in vivo absorption cross section normalized to Chl a(a{sup *}), but decreased the maximum quantum yield of photosynthesis ({phi}{sub m}). Thus, the product a{sup *} {phi}{sub m}, which equals the Chl a-specific initial slope of the photosynthesis-irradiance curve ({alpha}{sup B}), was less sensitive to Fe limitation than was a{sup *} or {phi}{sub m} alone. Using a pump-and-probe fluorometer, the authors found that Fe deficiency reduced the maximum fluorescence yield ({Delta}{phi}{sub sat}), which is consistent with the reduction in {phi}{sub m}, but increased the absorption cross section of photosystem 2 ({sigma}{sub PS2}). Immunoassays of proteins separated electrophoretically indicated that the reduction in maximum fluorescence yields as accompanied by a reduction in the relative abundance of D1, the photosystem 2 reaction center protein. Light-harvesting chlorophyll proteins (LHCP) and the large and small subunits of ribulose bisphosphate carboxylase were not affected by Fe deficiency. Changes in the abundance of D1 relative to LHCP suggest an increase in the fraction of nonfunctional reaction centers under Fe-limited conditions. Fe-deficient cells, growing at <20% of their maximum growth rate, and reduced cellular C, N, and P contents, but maintained C:N:P ratios at the Redfield proportions. These results imply that C:N:P ratios do not provide and unequivocal index of relative growth rate.

  9. Release Fraction Evaluation

    SciTech Connect

    Bamberger, Judith A.; Glissmeyer, John A.

    2004-01-01

    This document presents results of experiments conducted to measure release fractions during certain tank retrieval processes. The tests were performed in a 1/4 scale model of a waste storage tank. The retrieval processes simulated were: (1) Discharging liquid or slurry from the mouth of a vertically oriented two-in. Schedule 40 pipe. The discharging material was in free-fall from the mouth of the pipe near the top of the tank into a liquid or slurry pool at the bottom of the tank. (2) The jet from a 9/16-in.-diameter nozzle transferring liquid or slurry waste from one side of the tank to the other. The discharging liquid was aimed at the opposite side of the tank from the nozzle and either impacted the tank wall or fell into a liquid or slurry pool in the bottom of the tank. (3) A high pressure fan jet of liquid striking a steel plate or simulated waste from a stand-off distance of a few inches. For each process, a water-soluble fluorescent dye was added to the liquid fraction as a tracer. Kaolin clay was used to represent the solids. The tank was covered and there was no forced ventilation in the tank during the tests. Six air samples were collected during each test. The air samples were collected at fixed positions in the tank. The air sample filters were dried and weighed to determine the solids collection. The fluorescent dye was then leached from each filter and quantified with a fluorometer to determine the collection of liquid. Samples of the slurry and liquid simulants were also collected to determine the quantities of simulant used in each test. To calculate the release fraction, the quantity collected on each air sample was adjusted for the fraction of the tank volume sampled and divided by the quantity of material exposed in the simulation. The method was not as sensitive for the solids content as it was for the liquid content, but in those instances where a solids release fraction was determined, it was in relatively good agreement with that of the

  10. Comparison of Hydraulic Methods and Tracer Experiments as Applied to the Development of Conceptual Models for Discrete Fracture Networks

    NASA Astrophysics Data System (ADS)

    Novakowski, K. S.

    2015-12-01

    The development of conceptual models for solute migration in discrete fracture networks has typically been based on a combination of core logs, borehole geophysics, and some form of single-well hydraulic test using discrete zones. More rarely, interwell hydraulic tests and interwell tracer experiments are utilised to directly explore potential transport pathways. The latter methods are less widely employed simply due to potentially significant increases in the cost and effort in site characterization. To date however there is a paucity of literature comparing the efficacy of the standard procedure with what should be more definitive identification of transport pathways using interwell methods. In the present study, a detailed comparison is conducted by developing conceptual models from three separate data sets, the first based on core logs, geology and single-well hydraulic tests, the second based on a large suite of pulse interference tests, and the third based on a series of radially-divergent and injection-withdrawal tracer experiments. The study was conducted in an array of five HQ-sized wells, 28-32 m in depth and arranged in a five star pattern, 10 m on a side. The wells penetrate the contact between a Cambrian-aged limestone, and underlying Precambrian gneiss. The core was logged for potentially open fractures using a ranking system, and 87 contiguous hydraulic tests were conducted using a 0.85-m packer spacing. A total of 57 pulse interference tests were conducted using two wells as injection points, and 11 tracer experiments were conducted using either sample collection or in-situ detection via a submersible fluorometer. The results showed very distinct conceptual models depending on the data set, with the model based on the single-well testing significantly over-predicting the number and connection of solute transport pathways. The results of the pulse interference tests also over predict the transport pathways, but to a lesser degree. Quantification of

  11. The New Seafloor Observatory (OBSEA) for Remote and Long-Term Coastal Ecosystem Monitoring

    PubMed Central

    Aguzzi, Jacopo; Mànuel, Antoni; Condal, Fernando; Guillén, Jorge; Nogueras, Marc; del Rio, Joaquin; Costa, Corrado; Menesatti, Paolo; Puig, Pere; Sardà, Francesc; Toma, Daniel; Palanques, Albert

    2011-01-01

    A suitable sampling technology to identify species and to estimate population dynamics based on individual counts at different temporal levels in relation to habitat variations is increasingly important for fishery management and biodiversity studies. In the past two decades, as interest in exploring the oceans for valuable resources and in protecting these resources from overexploitation have grown, the number of cabled (permanent) submarine multiparametric platforms with video stations has increased. Prior to the development of seafloor observatories, the majority of autonomous stations were battery powered and stored data locally. The recently installed low-cost, multiparametric, expandable, cabled coastal Seafloor Observatory (OBSEA), located 4 km off of Vilanova i la Gertrú, Barcelona, at a depth of 20 m, is directly connected to a ground station by a telecommunication cable; thus, it is not affected by the limitations associated with previous observation technologies. OBSEA is part of the European Multidisciplinary Seafloor Observatory (EMSO) infrastructure, and its activities are included among the Network of Excellence of the European Seas Observatory NETwork (ESONET). OBSEA enables remote, long-term, and continuous surveys of the local ecosystem by acquiring synchronous multiparametric habitat data and bio-data with the following sensors: Conductivity-Temperature-Depth (CTD) sensors for salinity, temperature, and pressure; Acoustic Doppler Current Profilers (ADCP) for current speed and direction, including a turbidity meter and a fluorometer (for the determination of chlorophyll concentration); a hydrophone; a seismometer; and finally, a video camera for automated image analysis in relation to species classification and tracking. Images can be monitored in real time, and all data can be stored for future studies. In this article, the various components of OBSEA are described, including its hardware (the sensors and the network of marine and land nodes

  12. Deposition from Ultra-Low Volume Application of Public Health Insecticides in a Hot Desert Environment.

    PubMed

    Fisher, Michael L; Hoel, David F; Farooq, Muhammad; Walker, Todd W

    2015-06-01

    Three insecticides commonly used for mosquito and sand fly control were applied 30 min to 3 h after sunset during June and July 2010, at Camp Buehring, Kuwait, to determine the relative quantity of pesticides to height and distance traveled in a hot desert environment. A BVA dilution oil was used for the control. Oil-based adulticides were sprayed using a truck-mounted Curtis DynaFog Maxi-Pro 4 ultra-low volume (ULV) sprayer. Malathion (Fyfanon ULV, 96% active ingredient [AI]), resmethrin (Scourge 4+12, 4% AI), pyrethrins (ULD BP-300, 3% AI), and BVA Spray 13 (100% refined petroleum distillate) were mixed with Uvitex optical brightener fluorescent dye and applied at 2 speeds on evenings when wind speed was less than 16.1 km/h (10 mph). Collection targets using biodegradable cotton ribbons (1 m×2.5 cm) were later read with a fluorometer to quantify the amount of insecticide deposited on targets set at heights of 15.2, 76.2, and 152.4 cm (6, 30, and 60 in.) and distances of 1.5, 6.1, 15.2, 30.5, 61.0, and 91.4 m (5, 20, 50, 100, 200, and 300 ft). Mean insecticide deposition across all distances was 31% on 76.2-cm targets and 49% on 152.4-cm targets, while 15.2-cm targets typically collected <20% of test spray. Mean ground temperatures were typically within 5°C of air temperatures at 152.4 cm and within 1 to 5°C of air at 15.2 cm or 76.2 cm. Collectively, mean insecticide deposition was 80% at or above 76.2 cm for all insecticides. This finding may explain in part why control of low-flying phlebotomine sand flies with ULV insecticides has been met with less than optimal success by US military forces deployed in the Middle East.

  13. Potential of front-face fluorescence to monitor OM reduction in drinking water during potabilization process

    NASA Astrophysics Data System (ADS)

    Lacotte, Pierre

    2014-05-01

    Elimination of OM in drinking water represents a great challenge for municipalities and technical actors to ensure that it can be safely used for consumption purposes. Indeed, current indicators such as Total Organic Carbon (TOC), turbidity or UV-Absorbance at 254 nm (UVA254) enable only non-specific overview of the amount of organic residuals in water. Fluorescence EEMs are a potent tool for discrimination and deep analysis of OM detailed composition and behaviour. It has been shown that several forms of OM co-exist in raw water, and come from various origins (bacteria, humic compounds…). Potabilization operation is composed of different steps that aim at decreasing all forms of OM using chemical as well as physical methods (ozone oxidation, filtration on activated carbon or sand, flocculation etc.). Unfortunately, it has been observed that reduction of OM during this process was not identical for all the forms, and the process showed a particular lack of efficiency during raining periods. 130 samples of water at various stages of potabilization were analyzed using home-made compact fluorometer, an apparatus composed of UV excitation LEDs. Using chemometrical treatment of spectral data, we put into highlight 5 different forms of OM that were identified according to litterature data. We evidenced the critical steps of the purification on OM reduction, as well as the relative content of each form from raw to product water. In particular, we showed that two forms were less reduced than the other three, so that progressive enrichment of total OM in the former was observed throughout the process. Moreover, a study was carried out in order to establish calibration models over conventional analyses using the spectral information. Highly satisfying models were thus obtained over TOC, turbidity and UVA254, with average RMSEC values of 13%, 7% and 16% respectively. These results demonstrate the potential of the fluorescence analyzer to simultaneously predict three major

  14. Dissolved Zinc Measurements Using Shipboard FIA During the 2008 GEOTRACES Cruise

    NASA Astrophysics Data System (ADS)

    Gosnell, K. J.; Landing, W. M.; Milne, A.

    2008-12-01

    Zinc concentrations in the open ocean have been measured accurately by only a few investigators due to the extreme difficulties of collecting and processing seawater samples without introducing Zn contamination. Accurate measurements of dissolved Zn are important for understanding the biogeochemical behavior of this important biochemically required element in the open ocean. Historically, reliable samples for dissolved Zn were collected using Teflon-coated GO-FLO bottles individually hung on Kevlar line. To speed up sample collection, two "Trace Metal" rosette systems were tested during Leg 1 of the GEOTRACES 2008 intercalibration cruise: a large GEOTRACES 24-bottle rosette and the smaller Measures and Landing "CLIVAR" 12-bottle rosette. Both rosettes use 12-liter, Teflon-coated GO- FLO bottles equipped with Teflon spigots and modified air-relief fittings, allowing for pressure filtration. Contamination for dissolved Zn was eliminated in the 12-liter Teflon-lined GO-FLO bottles by repeated deployments ("flushing") on both rosette systems. A Flow Injection (FIA) technique for shipboard determination of total dissolved Zn was utilized to test rosette sampling methods for Zn contamination. Samples were acidified to 0.024M HCl (pH 2) for 16 hours. Samples were buffered to pH 5.5 using ammonium acetate buffer. Dissolved Zn was pre-concentrated using a small- volume column of 8-HQ cation exchange resin. After column rinsing, Zn was eluted into the flowing stream of organic reagent p-Tosyl-8-aminoquinoline (pTAQ), which forms fluorescent complexes with Zn. A flow- through fluorometer was used to record peak heights. Calibration was performed via standard additions. Accuracy of this method was established by measuring standard SAFe D2 and S1 samples, as well as multiple samples collected and analyzed throughout Leg 1 of the GEOTRACES 2008 cruise. Dissolved Cadmium (Cd) can additionally form fluorescent complexes with pTAQ. Thus, when necessary, a small, positive, Cd

  15. Development, evaluation and comparison of two independent sampling and analytical methods for ortho-phthalaldehyde vapors and condensation aerosols in air† ‡

    PubMed Central

    2015-01-01

    Two independent sampling and analytical methods for ortho-phthalaldehyde (OPA) in air have been developed, evaluated and compared (1) a reagent-coated solid sorbent HPLC-UV method and (2) an impinger-fluorescence method. In the first method, air sampling is conducted at 1.0 L min−1 with a sampler containing 350 mg of silica gel coated with 1 mg of acidified 2,4-dinitrophenylhydrazine (DNPH). After sampling, excess DNPH in ethyl acetate is added to the sampler prior to storage for 68 hours. The OPA-DNPH derivative is eluted with 4.0 mL of dimethyl sulfoxide (DMSO) for measurement by HPLC with a UV detector set at 3S5 nm. The estimated detection limit is 0.016 µg per sample or 0.067 µg m−3 (0.012 ppb) for a 240 L air sample. Recoveries of vapor spikes at levels of 1.2 to 6.2 µg were 96 to 101%. Recoveries of spikes as mixtures of vapor and condensation aerosols were 97 to 100%. In the second method, air sampling is conducted at 1.0 L mm−1 with a midget impinger containing 10 mL of DMSO solution containing N-acetyl-l-cysteine and ethylenediamine. The fluorescence reading is taken 80 min after the completion of air sampling. Since the time of taking the fluorescence reading is critical, the reading is taken with a portable fluorometer. The estimated detection limit is 0.024 µg per sample or 0.1 µg m−3 (0.018 ppb) for a 240 L air sample. Recoveries of OPA vapor spikes at levels of 1.4 to 5.0 µg per sample were 97 to 105%. Recoveries of spikes as mixtures of vapors and condensation aerosols were 95 to 99%. The collection efficiency for a mixture of vapor and condensation aerosol was 99.4%. The two methods were compared side-by-side in a generation system constructed for producing controlled atmospheres of OPA vapor in air. Average air concentrations of OPA vapor found by both methods agreed within ±10%. PMID:26346658

  16. [Research on Accuracy and Stability of Inversing Vegetation Chlorophyll Content by Spectral Index Method].

    PubMed

    Jiang, Hai-ling; Yang, Hang; Chen, Xiao-ping; Wang, Shu-dong; Li, Xue-ke; Liu, Kai; Cen, Yi

    2015-04-01

    Spectral index method was widely applied to the inversion of crop chlorophyll content. In the present study, PSR3500 spectrometer and SPAD-502 chlorophyll fluorometer were used to acquire the spectrum and relative chlorophyll content (SPAD value) of winter wheat leaves on May 2nd 2013 when it was at the jointing stage of winter wheat. Then the measured spectra were resampled to simulate TM multispectral data and Hyperion hyperspectral data respectively, using the Gaussian spectral response function. We chose four typical spectral indices including normalized difference vegetation index (NDVD, triangle vegetation index (TVI), the ratio of modified transformed chlorophyll absorption ratio index (MCARI) to optimized soil adjusted vegetation index (OSAVI) (MCARI/OSAVI) and vegetation index based on universal pattern decomposition (VIUPD), which were constructed with the feature bands sensitive to the vegetation chlorophyll. After calculating these spectral indices based on the resampling TM and Hyperion data, the regression equation between spectral indices and chlorophyll content was established. For TM, the result indicates that VIUPD has the best correlation with chlorophyll (R2 = 0.819 7) followed by NDVI (R2 = 0.791 8), while MCARI/OSAVI and TVI also show a good correlation with R2 higher than 0.5. For the simulated Hyperion data, VIUPD again ranks first with R2 = 0.817 1, followed by MCARI/OSAVI (R2 = 0.658 6), while NDVI and TVI show very low values with R2 less than 0.2. It was demonstrated that VIUPD has the best accuracy and stability to estimate chlorophyll of winter wheat whether using simulated TM data or Hyperion data, which reaffirms that VIUPD is comparatively sensor independent. The chlorophyll estimation accuracy and stability of MCARI/OSAVI also works well, partly because OSAVI could reduce the influence of backgrounds. Two broadband spectral indices NDVI and TVI are weak for the chlorophyll estimation of simulated Hyperion data mainly because of

  17. Autonomous Sampling of Remote Phytoplankton Blooms in the North Pacific Subtropical Gyre (July-Aug. 2015).

    NASA Astrophysics Data System (ADS)

    Anderson, E. E.; Wilson, C.; Villareal, T. A.

    2016-12-01

    Satellite ocean color data regularly reveals the existence of large (103 km2) phytoplankton blooms in the North Pacific Ocean that can persist for weeks to months and are often associated with N2 fixing diatom symbioses. The basin size and inability to accurately forecast these blooms makes sampling these events difficult outside of the time series at Station ALOHA. We used an autonomous Wave Glider surface vehicle (Honey Badger) to conduct a large regional survey well north of HI to examine bloom composition and key species distribution. Honey Badger was equipped with a gpCTD, downward looking camera, 2 C3 fluorometers, wind and wave sensors, a Turner Designs' Phytoflash, and a Sequoia Scientific LISST-Holo for imaging cells. Most of the data collected was available in near-real time through NOAA's ERDDAP data server. The 159 day mission began 1 June 2015 and covered 6800 km. From 1 July 2015 to 31 August 2015, Honey Badger transited from low levels of chlorophyll-a (chl) (0.06±0.01 mg m-3), through a mesoscale­ bloom, and then into a broad regional chl increase (0.08±0.01 mg m-3) as noted by the AQUA MODIS satellite. Phytoplankton cell counts (> 14,000 Hemiaulus cells L-1) and increased nocturnal Fv:Fm yields (maximum > 0.61) were concurrent with the 0.1 µg Chl L-1 bloom. A separate bloom of the Rhizosolenia-Richelia symbiosis was noted (> 3,000 Rhizosolenia-Richelia cells L-1) within a smaller, short-lived bloom with a biovolume 2.1 times higher than the rest of the southern transect. The broad regional chl increase in the southern leg of the transit was concurrent with a sustained Hemiaulus increase to 102 cells L-1. Diel patterns in Fv:Fm did not suggest Fe limitation anywhere in the transect. Elevated yields were found only in the diatom increases. Honey Badger and the instruments it carried were useful tools for the investigation of remote bloom dynamics in the Eastern North Pacific Subtropical Gyre.

  18. Diffuse reflectance spectroscopy can differentiate high grade and low grade prostatic carcinoma.

    PubMed

    Werahera, Priya N; Jasion, Edward A; David Crawford, E; Lucia, M Scott; van Bokhoven, Adrie; Sullivan, Holly T; Kim, Fernando J; Maroni, Paul D; David Port, J; Daily, John W; Rosa, Francisco G La; Werahera, Priya N; Jasion, Edward A; Crawford, E David; Lucia, M Scott; van Bokhoven, Adrie; Sullivan, Holly T; Kim, Fernando J; Maroni, Paul D; Port, J David; Daily, John W; La Rosa, Francisco G; Daily, John W; Van Bokhoven, Adrie; Crawford, E David; Port, J David; Werahera, Priya N; Lucia, M Scott; Sullivan, Holly T; Maroni, Paul D; Jasion, Edward A; La Rosa, Francisco G; Kim, Fernando J

    2016-08-01

    Prostate tumors are graded by the revised Gleason Score (GS) which is the sum of the two predominant Gleason grades present ranging from 6-10. GS 6 cancer exclusively with Gleason grade 3 is designated as low grade (LG) and correlates with better clinical prognosis for patients. GS >7 cancer with at least one of the Gleason grades 4 and 5 is designated as HG indicate worse prognosis for patients. Current transrectal ultrasound guided prostate biopsies often fail to correctly diagnose HG prostate cancer due to sampling errors. Diffuse reflectance spectra (DRS) of biological tissue depend on tissue morphology and architecture. Thus, DRS could potentially differentiate between HG and LG prostatic carcinoma. A 15-gauge optical biopsy needle was prototyped to take prostate biopsies after measuring DRS with a laboratory fluorometer. This needle has an optical sensor that utilizes 8×100 μm optical fibers for tissue excitation and a single 200 μm central optical fiber to measure DRS. Tissue biopsy cores were obtained from 20 surgically excised prostates using this needle after measuring DRS at 5 nm intervals between 500-700 nm wavelengths. Tissue within a measurement window was histopathologically classified as either benign, LG, or HG and correlated with DRS. Partial least square analysis of DRS identified principal components (PC) as potential classifiers. Statistically significant PCs (p<;0.05) were tested for their ability to classify biopsy tissue using support vector machine and leave-one-out cross validation method. There were 29 HG and 49 LG cancers among 187 biopsy cores included in the study. Study results show 76% sensitivity, 80% specificity, 93% negative predictive value, and 50% positive predictive value for HG versus benign, and 76%, 73%, 84%, and 63%, for HG versus LG prostate tissue classification. DRS failed to diagnose 7/29 (24%) HG cancers. This study demonstrated that an optical biopsy needle guided by DRS has sufficient accuracy to differentiate HG

  19. Diurnal changes of photosynthetic quantum yield in the intertidal macroalga Sargassum thunbergii under simulated tidal emersion conditions

    NASA Astrophysics Data System (ADS)

    Yu, Yong Qiang; Zhang, Quan Sheng; Tang, Yong Zheng; Li, Xue Meng; Liu, Hong Liang; Li, Li Xia

    2013-07-01

    In this study, a three-way factorial experimental design was used to investigate the diurnal changes of photosynthetic activity of the intertidal macroalga Sargassum thunbergii in response to temperature, tidal pattern and desiccation during a simulated diurnal light cycle. The maximum (Fv/Fm) and effective (ΦPSII) quantum yields of photosystem II (PSII) were estimated by chlorophyll fluorescence using a pulse amplitude modulated fluorometer. Results showed that this species exhibited sun-adapted characteristics, as evidenced by the daily variation of Fv/Fm and ΦPSII. Both yield values decreased with increasing irradiance towards noon and recovered rapidly in the afternoon suggesting a dynamic photoinhibition. The photosynthetic quantum yield of S. thunbergii thalli varied significantly with temperature, tidal pattern and desiccation. Thalli were more susceptible to light-induced damage at high temperature of 25 °C and showed complete recovery of photosynthetic activity only when exposed to 8 °C. In contrast with the mid-morning low tide period, although there was an initial increase in photosynthetic yield during emersion, thalli showed a greater degree of decline at the end of emersion and remained less able to recover when low tide occurred at mid-afternoon. Short-term air exposure of 2 h did not significantly influence the photosynthesis. However, when exposed to moderate conditions (4 h desiccation at 15 °C or 6 h desiccation at 8 °C), a significant inhibition of photosynthesis was followed by partial or complete recovery upon re-immersion in late afternoon. Only extreme conditions (4 h desiccation at 25 °C or 6 h desiccation at 15 °C or 25 °C) resulted in the complete inhibition, with little indication of recovery until the following morning, implying the occurrence of chronic PSII damage. Based on the magnitude of effect, desiccation was the predominant negative factor affecting the photosynthesis under the simulated daytime irradiance period. These

  20. Subsurface new production in the northwestern subtropical North Pacific fueled by nutrients from the Subtropical Mode Water

    NASA Astrophysics Data System (ADS)

    Suga, T.; Sukigara, C.; Saino, T.; Toyama, K.; Yanagimoto, D.; Hanawa, K.; Shikama, N.; Tsubono, K.; Kobayashi, T.; Hosoda, S.; Hibiya, T.; Furuichi, N.

    2010-12-01

    Substantial sustained subsurface new production during summer in the northwestern subtropical North Pacific is demonstrated, with its mechanism being proposed, based on observation by a profiling float and a synoptic survey by a research vessel. The profiling float equipped with a fluorometer, a dissolved oxygen (DO) sensor, and temperature and salinity sensors was deployed in the Subtropical Mode Water (STMW) formation region. It acquired quasi-Lagrangian, 5-day-interval time-series records from March to July 2006. The time-series distribution of chlorophyll showed a sustained and sizable subsurface maximum at 50-100 m, just above the upper boundary of the STMW, throughout early summer (May-July). The DO concentration in the lower euphotic zone (50-100 m) had been supersaturated in the same period but did not show a net increment. On the other hand, the DO concentration at 100-150 m near the upper edge of the STMW, which was below the euphotic zone, decreased very slightly, in spite of expected oxygen consumption by organisms at least as large as that appearing at 150-300 m. These small temporal variations of dissolved oxygen in the lower euphotic zone and near the upper edge of the STMW are explained by downward oxygen transport due to large diffusion near the top of the STMW. The estimated diffusivity based on an assumption of the large downward transport of oxygen is 1.5 × 10-4 m-2 s-1. The upward nitrate transport into the euphotic zone by the same diffusion is estimated to be 0.7 mmol N m-2 d-1 with using vertical profiles of nitrates obtained by ship-board measurements in the vicinity of the float. Assuming all of the transported nitrate be used for photosynthesis by the phytoplankton, the net community production is estimated to be 4.8 mmol C m-2 d-1. The large diffusivity near the top of the STMW is possibly associated with an abrupt decrease in buoyancy frequency there, which may prevents downward transmission of internal waves generated in the surface

  1. Analysis of Lake Baikal's phytoplankton and fluvial input dynamics using SeaWiFS satellite data within the Scope of the Paleoclimate Project CONTINENT

    NASA Astrophysics Data System (ADS)

    Heim, B.; Oberhaensli, H.; Kaufmann, H.

    2003-04-01

    Multispectral ocean colour satellite data provide a new tool for spatial and temporal limnological data overview. The Ulaan Baatar (Mongolia) HRPT (high resolution picture transmission) station provides the paleoclimate EC-Project CONTINENT "High Resolution CONTINENTal Paleoclimate Record in Lake Baikal (Siberia, Russia)" with daily SeaWiFS data covering the area of south-eastern Siberia. After a SeaWiFS data processing chain with radiometric and atmospheric correction, we use the water leaving reflectances to gain information on phytoplankton and suspended sediment whose dynamics are a response to the present climate forcing. During the CONTINENT Summer cruises in 2001 and 2002, we were able to verify the spectral analysis of SeaWiFS satellite data with a high quality calibration/validation ground truth data set (field spectrometer and fluorometer measurement activities simultaneously to water sampling activities for pigment and suspended matter SPM and DOC analysis and algae counting). The fluviatil input into Lake Baikal is visible in the SeaWiFS data due to its higher loads of suspended matter, further particularly due to the presence of coloured dissolved organic matter (cDOM). These coloured fraction of DOM (mainly humic acids) originate from the bog areas and swampy basins within the Lake Baikal watershed. The so called yellow substances react optically with a strong absorption in the blue spectral bands of SeaWiFS and are therefore ideal tracers for the river input even over long distances from the river inflow. The phytoplankton main pigment chlorophyll-a is made visible by its absorption band in the blue which results in a green reflectance peak. Additional pigment groups (carotinoids, phycobilins) differentiate the spectral shape of the water leaving reflectance depending on the respective main phytoplankton composition. On satellite images obtained in late Summer, we can differentiate between diatom and cyanobacteria-picoplankton dominated surface water

  2. Detection and Localization of Pre-Cancerous Lesions and Early Lung Cancer Using Tissue Autofluorescence.

    NASA Astrophysics Data System (ADS)

    Hung, Jaclyn Yip-Chan

    In this work, two different yet related hypotheses were tested by experimental means as follows: (i) pre-cancerous and non-invasive (early) lung cancer can be detected and localized using the fluorescence properties of tumour localizing drugs at non-photosensitizing doses to skin tissue; (ii) significant differences exist in laser-induced autofluorescence between normal, pre-cancerous and cancerous tissues such that these differences alone can be exploited to detect and delineate early lung cancer without using exogenous drug(s). Exogenous fluorescent tumour markers such as hematoporphyrin derivatives (e.g. Photofrin) have been used to enhance to detection of occult lung lesions. Photofrin is preferentially retained in tumor tissues compared to the surrounding normal tissues; it fluoresces at 630 nm and 690 nm when excited at -405 nm. Based on this principle several imaging and non-imaging devices have been developed. However, wider clinical applications were limited due to the skin photosensitivity property of Photofrin. We have postulated that this could be solved by employing a much lower dose of Photofrin (0.25 mg/kg) which was believed to be less photosensitizing to human patients. This postulate was experimentally tested by ratio fluorometry and early lung cancers were detected with no false negative results and no apparent skin photosensitivity. An important finding in this study was that the mechanism for detection of early cancer was mainly due to the differences in the green autofluorescence between normal and malignant tissues, rather than fluorescence of tumour localizing drug. This discovery led to the second postulate of this thesis that tissue autofluorescence alone can be exploited for the detection of early lung cancer. The results indicated that algorithm(s) could be developed to clearly delineate early lesions from the normal tissues. Several algorithms were then tested using a non-imaging ratio fluorometer device and a prototype imaging

  3. Community-level microalgal toxicity assessment by multiwavelength-excitation PAM fluorometry.

    PubMed

    Schmitt-Jansen, Mechthild; Altenburger, Rolf

    2008-01-20

    In ecotoxicological studies involving community-level investigations, rapid and multiparametric fluorescence-based methods may provide substantial advantages over traditional methods used for structural and functional community analysis. Therefore, multiwavelength-excitation pulse-amplitude modulated (PAM) fluorometry was applied in this study to assess long-term changes in periphyton community structure, short-term effects on periphyton functioning (photosynthesis) and pollution induced community tolerance (PICT). For inter-calibration, periphyton structure was evaluated by chemotaxonomic analysis of accessory pigments and a four-wavelength-excitation PAM fluorometer. Short-term effects of herbicides were evaluated by fluorescence quenching analysis and (14)C-incorporation as a proxy of primary production. Subsequently, the method was applied to assess structural and functional changes in periphyton communities after isoproturon exposure for 14 and 26 days, respectively. Results showed good correlation of the PAM fluorescence-based measurements with traditional methods for biofilms in the initial colonisation phase for structural and functional parameters. However, for biofilms older than 9 weeks PAM fluorescence may underestimate biomass. Multiwavelength-excitation PAM fluorometry showed good correlation with marker pigment concentrations indicating that this method provides a reliable estimate of the community structure. PAM fluorometry was able to quantify changes of biomass and follow relative shifts in class composition of biofilms under exposure of isoproturon. Short-term tests based on the quantification of the inhibition of the effective quantum yield revealed a concentration-dependent increase of PICT. The observation of two succession phases of the biofilms after 14 and 26 days of growth, respectively, revealed that sensitivity of biofilms decreased with increasing age and biomass, respectively, but PICT remained a characteristic parameter of exposed

  4. Fluorescence lifetimes of anthracycline drugs in phospholipid bilayers determined by frequency-domain fluorometry

    NASA Astrophysics Data System (ADS)

    Burke, Thomas G.; Malak, Henryk M.; Doroshow, James H.

    1990-05-01

    Time-resolved fluorescence intensity decay data from anthracycline anticancer drugs present in model membranes were obtained using a gigahertz frequency-domain fluorometer [Lakowicz et al. (1986) Rev. Sci. Instrum. 57, 2499-2506]. Exciting light of 290 nm, modulated at multiple frequencies from 8 MHz to 400 MHz, was used to study the interactions of Adriamycin, daunomycin and related antibiotics with small unilamellar vesicles composed of dimyristoylphosphatidylcholine (DMPC) at 28°C. Fluorescence decay data for drug molecules free in solution as well as bound to membranes were best fit by exponentials requiring two terms rather than by single exponential decays. For example, one-component analysis of the decay data for Adriamycin free in phosphate buffered saline (PBS) solution resulted in a reduced x2 value of 140 ((tau) = 0.88 ns), while a two-component fit resulted in a substantially smaller reduced x2 value of 2.6 ((tau)1 = 1.13 ns, (alpha)1 = 0.60, (tau)2 = 0.30 ns). Upon association with membranes, each of the anthracyclines studied displayed a larger r1 value while the r2 value remained the same or increased (for example, DMPC-bound Adriamycin showed r1 = 1.68 ns , a1 = 0 . 64 , r2 = 0 . 33 ns) . Analyses of the fluorescence emission decays of anthracyclines were also made assuming each decay is composed of a single Lorentzian distribution of lifetimes. Data taken on Adriamycin in PBS, when fit using one continuous component, displayed (tau), (alpha), w, and reduced x2 values of 0.68 ns, 1, 0.60 ns, and 9.1, respectively. The distribution became quite broad upon drug association with membrane (DMPCbound Adriamycin: (tau) = 0.75 ns, (alpha) = 1, w = 2.24 ns, x2 = 13). For each anthracycline studied, continuous component fits showed significant broadening in the distributions upon drug association with membrane. Relatively large shifts in lifetime values were observed for the carminomycin and 4-demethoxydaunomycin analogues upon binding model lipid membranes

  5. Characterisation of dissolved organic matter (DOM) in the Seine River catchment (France) by excitation-emission matrix (EEM) fluorescence spectroscopy combined with PARAFAC and PCA analyses

    NASA Astrophysics Data System (ADS)

    Thanh Nguyen, Phuong; Guo, Yuzhe; Bonnot, Caroline; Varrault, Gilles; Benedetti, Marc; Parlanti, Edith

    2014-05-01

    Dissolved organic matter (DOM) is a heterogeneous, complex mixture of compounds with wide ranging chemical properties and diverse origins. It is well known to interact with pollutants and to affect their transport and their fate in aquatic environment, and plays a vital role in the global cycling of carbon. In this study, UV/visible absorbance and excitation emission matrix (EEM) fluorescence spectroscopy combined with PARAFAC and PCA analyses have been used to characterize colloidal DOM in the Seine River watershed. Surface water samples were collected in November 2011, September 2012 (low-water) and February 2013 (flood) from 23, 39 and 45 sites respectively from different areas including the Oise basin, the Marne basin, the Grand Morin basin and the downstream of the Seine River. A Jasco V-560 spectrophotometer was used for UV/visible absorbance measurement. Fluorescence spectra were recorded using a Fluorolog FL3-22 SPEX - JOBIN YVON fluorometer. The samples, at natural pH, were placed in 1 cm quartz cuvette, thermostated at 20°C. All sample spectra were obtained by subtracting a blank spectrum (ultrapure water Milli-Q, Millipore) and were instrumentally corrected. When necessary, samples were diluted to avoid inner filter effects. The fluorescence data set was analyzed using PARAFAC DOMFluor toolbox in Matlab which decomposes the complex data matrix into its main components. The application of UV/visible absorbance and EEM fluorescence spectroscopy in combination with PARAFAC and PCA analyses allowed us to identify different sources of dissolved organic matter in the catchment of the Seine River and highlighted spatial and temporal variations of DOM properties. We observed significant different and specific typologies of organic matter for the four studied zones. The Seine basin is characterized by the strongest biological activity (in connection with the presence of the "Seine-Aval" WWTP). DOM from the Oise basin seems to have more "humic" characteristics (a

  6. Pitfalls of DNA Quantification Using DNA-Binding Fluorescent Dyes and Suggested Solutions

    PubMed Central

    Nakayama, Yuki; Yamaguchi, Hiromi; Einaga, Naoki; Esumi, Mariko

    2016-01-01

    The Qubit fluorometer is a DNA quantification device based on the fluorescence intensity of fluorescent dye binding to double-stranded DNA (dsDNA). Qubit is generally considered useful for checking DNA quality before next-generation sequencing because it measures intact dsDNA. To examine the most accurate and suitable methods for quantifying DNA for quality assessment, we compared three quantification methods: NanoDrop, which measures UV absorbance; Qubit; and quantitative PCR (qPCR), which measures the abundance of a target gene. For the comparison, we used three types of DNA: 1) DNA extracted from fresh frozen liver tissues (Frozen-DNA); 2) DNA extracted from formalin-fixed, paraffin-embedded liver tissues comparable to those used for Frozen-DNA (FFPE-DNA); and 3) DNA extracted from the remaining fractions after RNA extraction with Trizol reagent (Trizol-DNA). These DNAs were serially diluted with distilled water and measured using three quantification methods. For Frozen-DNA, the Qubit values were not proportional to the dilution ratio, in contrast with the NanoDrop and qPCR values. This non-proportional decrease in Qubit values was dependent on a lower salt concentration, and over 1 mM NaCl in the DNA solution was required for the Qubit measurement. For FFPE-DNA, the Qubit values were proportional to the dilution ratio and were lower than the NanoDrop values. However, electrophoresis revealed that qPCR reflected the degree of DNA fragmentation more accurately than Qubit. Thus, qPCR is superior to Qubit for checking the quality of FFPE-DNA. For Trizol-DNA, the Qubit values were proportional to the dilution ratio and were consistently lower than the NanoDrop values, similar to FFPE-DNA. However, the qPCR values were higher than the NanoDrop values. Electrophoresis with SYBR Green I and single-stranded DNA (ssDNA) quantification demonstrated that Trizol-DNA consisted mostly of non-fragmented ssDNA. Therefore, Qubit is not always the most accurate method for

  7. Measurement of geologic nitrogen using mass spectrometry, colorimetry, and a newly adapted fluorometry technique

    NASA Astrophysics Data System (ADS)

    Johnson, Benjamin W.; Drage, Natashia; Spence, Jody; Hanson, Nova; El-Sabaawi, Rana; Goldblatt, Colin

    2017-03-01

    Long viewed as a mostly noble, atmospheric species, recent work demonstrates that nitrogen in fact cycles throughout the Earth system, including the atmosphere, biosphere, oceans, and solid Earth. Despite this new-found behaviour, more thorough investigation of N in geologic materials is limited due to its low concentration (one to tens of parts per million) and difficulty in analysis. In addition, N can exist in multiple species (NO3-, NH4+, N2, organic N), and determining which species is actually quantified can be difficult. In rocks and minerals, NH4+ is the most stable form of N over geologic timescales. As such, techniques designed to measure NH4+ can be particularly useful.We measured a number of geochemical rock standards using three different techniques: elemental analyzer (EA) mass spectrometry, colorimetry, and fluorometry. The fluorometry approach is a novel adaptation of a technique commonly used in biologic science, applied herein to geologic NH4+. Briefly, NH4+ can be quantified by HF dissolution, neutralization, addition of a fluorescing reagent, and analysis on a standard fluorometer. We reproduce published values for several rock standards (BCR-2, BHVO-2, and G-2), especially if an additional distillation step is performed. While it is difficult to assess the quality of each method, due to lack of international geologic N standards, fluorometry appears better suited to analyzing mineral-bound NH4+ than EA mass spectrometry and is a simpler, quicker alternative to colorimetry.To demonstrate a potential application of fluorometry, we calculated a continental crust N budget based on new measurements. We used glacial tills as a proxy for upper crust and analyzed several poorly constrained rock types (volcanics, mid-crustal xenoliths) to determine that the continental crust contains ˜ 2 × 1018 kg N. This estimate is consistent with recent budget estimates and shows that fluorometry is appropriate for large-scale questions where high sample throughput

  8. Dissolved organic matter dynamics during storm events: combining in-situ and laboratory optical measurements to improve understanding

    NASA Astrophysics Data System (ADS)

    Khamis, Kieran; Bradley, Chris; Hannah, David; Stevens, Rob

    2015-04-01

    Despite the crucial role of dissolved organic matter (DOM) in catchment biogeochemistry; DOM fluxes from watersheds still remains poorly characterized. Recently, the mobilization and transport of DOM during storm events has received increased attention; with significant changes in DOM quality and quantity reported for forested and agricultural catchments. However, for urban systems, our understanding of the extent to which storms drive changes in DOM concentration and composition remains limited, particularly with regards to intra/inter-seasonal variability. In this study, we address this research gap by characterizing a number of storm events on a small urban stream (Bournbrook, Birmingham, U.K) during the winter and summer of 2014. An in-situ submersible fluorometer (Cyclops 7, Turner Inc.) was integrated with a traditional water quality sonde (Manta 2, Eureka) to obtain a continuous record of tryptophan-like fluorescence (TLF: BOD surrogate), turbidity, electrical conductivity (EC), water temperature (Tw) and stage. River water samples were collected using an automatic pump sampler at ≤ 1hr intervals and returned to the lab for a suite of analyses (total carbon quantification, absorbance and excitation emission spectrofluorometry). The flow regime was typical of an urban/suburban catchment with river stage extremely responsive to rainfall with lag times of <3 hrs. Both winter and summer storm events exhibited first flush responses with peak turbidity either on the rising limb or at peak discharge for all events (max. turbidity = 400NTU). Field and lab data highlighted systematic overestimation of in-situ TLF during base flow and high flow. Robust correction factors were developed and significantly improved the relationship between field and filtered lab measurements (R2> 0.8). The highest TLF values (in-situ and lab) were recorded during summer events, with corresponding winter events consistently displaying lower TLF concentrations. Antecedent hydro

  9. Remote sensing techniques and in situ fluorometry as alternative methods for the determination of algae pigments in lakes - application to Lake Constance and small lakes

    NASA Astrophysics Data System (ADS)

    Wolf, Thomas; Heege, Thomas; Schenk, Karin; Stark, Markus; Stich, Hans-Bernd

    2014-05-01

    Satellite based remote sensing techniques were used in order to assess the variability of Chlorophyll-a distributions in Lake Constance and additionally within some smaller lakes in the South of Germany. For Lake Constance we used for most investigations spatially medium resolved satellite scanners with a higher spectral resolution whereas in the case of smaller lakes having a size of 1 … 10 km spatially highly resolved satellite scanners were used having a lower spectral resolution. The satellite imagery allowed for a higher spatial as well temporal resolution of information about Chlorophyll-a distribution in these lakes compared to classical methodologies as water sampling and subsequent species analysis using microscopes and/or HPLC analysis for accessory algae pigments. We found - depending on weather and hydrodynamic conditions - highly variable Chlorophyll-a distributions under some circumstances whereas there are as well time periods when almost perfectly homogeneous distributions of Chlorophyll-a where detected in Lake Constance. Additionally we used HPLC analysis in order to validate the satellite remote sensing results showing good agreement between in situ measured and remote sensing values for Chlorophyll-a. During some measurement campaigns in Lake Constance we used an in situ fluorometer probe (BBE FluoroProbe) in order to determine the spatial fluctuations of Chlorophyll-a and additional accessory algae pigments. These algae pigments were measured along horizontal transects using a temporal sampling interval of about dt=2 … 10 seconds giving a high spatial sampling frequency in the order O[10 … 50]m. Based on these horizontal records we can get further insight into the spatial fluctuations of algae pigments and their spatial patterns in Lake Constance. Characteristics of these patterns can be quantified using some patchiness state vector (psv) summarizing different specific features of the algae distribution into some vector quantity. Special

  10. Peripheral cytokines, C-X-C motif ligand10 and interleukin-13, are associated with Malaysian Alzheimer's disease.

    PubMed

    Mohd Hasni, Dayana Sazereen; Lim, Siong Meng; Chin, Ai Vyrn; Tan, Maw Pin; Poi, Philip Jun Hua; Kamaruzzaman, Shahrul Bahyah; Majeed, Abu Bakar Abdul; Ramasamy, Kalavathy

    2017-05-01

    Cytokines released from chronically-activated microglia could result in neuroinflammation. An accurate profile of the relationship between cytokines and Alzheimer's disease (AD) pathogenesis, as well as the patterns of these inflammatory mediators in AD patients could lead to the identification of peripheral markers for the disease. The present study was undertaken to identify pro- and anti-inflammatory cytokines associated with AD in the Malaysian population. Further to informed consent from 39 healthy subjects and 39 probable AD patients, 8.5 mL of peripheral blood was collected and serum was extracted. The differential levels of 12 serum cytokines extracted from peripheral blood samples were measured using Procarta Multiplex Cytokine and enzyme-linked immunoassay kits. Concentrations of cytokines were measured at 615 nm using a fluorometer. Except for tumor necrosis factor-α, all classical pro-inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-12 and interferon-γ) were found to be significantly upregulated (P < 0.001) in AD patients. Three of the five non-classical pro-inflammatory cytokines (C-X-C motif ligand 10 [CXCL-10], monocyte chemoattractant protein-1 and macrophage inflammatory protein-1α) showed similar patterns. Both classical IL-10 and non-classical IL-13 anti-inflammatory cytokines were significantly downregulated (P < 0.001) in AD patients when compared with non-AD controls. Receiver operating characteristic curve analyses for both CXCL-10 (IP-10) and IL-13 showed a high level of diagnostic accuracy (area under curve = 1 [95% confidence interval]). Both CXCL-10 and IL-13 also showed sensitivity of 100% and specificity of 100% for diagnosis of AD (cut-off values >53.65 ρg/mL and <9.315 ρg/mL, respectively). Both the non-classical pro-inflammatory CXCL-10 and anti-inflammatory IL-13 cytokines showed promising potential as blood-based cytokine biomarkers for AD. This is the first study of non-classical cytokine profiles

  11. Secondary production at the Polar Front, Barents Sea, August 2007

    NASA Astrophysics Data System (ADS)

    Basedow, Sünnje L.; Zhou, Meng; Tande, Kurt S.

    2014-02-01

    To investigate spatial patterns of secondary production we sampled four core hydrographical regions of the Polar Front in the Barents Sea (Arctic Water, ArW; Polar Front Water, PFW; Atlantic Water, AtW; and Melt Water, MW) by towing an undulating instrument platform along a transect crossing the front from August 8-9, 2007. Sensors mounted on the platform provided data on the hydrography (CTD), fluorescence (Fluorometer, F) and zooplankton abundance in the size range between 0.1 and 30 mm (Laser Optical Plankton Counter, LOPC). These continuous, biophysical data with high-spatial resolution were supplemented by discrete water and zooplankton net samples at stations for sensor calibrations. After in depth quality assessments of the biophysical data, estimates were made of the vital rates based on biovolume spectrum theory. Five size groups were distinguished from the LOPC data: small (S), mainly Oithona spp. and the appendicularian Fritillaria sp.; medium (M), mainly Pseudocalanus spp. and Calanus spp. CI-CIII; large (L), mainly Calanus spp. CIV-CV; and extra large (XL and 2XL), juvenile and adult euphausids. Size groups were further divided based on transparency of organisms. Vital rates based on the biophysical in situ data in combination with biovolume spectrum theories agreed generally well with data from empirical and numerical models in the literature. ArW was characterised by subsurface maxima of chlorophyll a (chl a), and an estimated population growth of ca. 13 mg C m- 3 d- 1 for CI-CIII Calanus spp. and some older Pseudocalanus within the chl a maxima. Frontal waters were characterised by low chl a concentrations, but high abundances and production (around 1 g C m- 3 d- 1) of small copepods (Oithona spp.) and appendicularians (Fritillaria sp.). The estimated production of small-size zooplankton was an order of magnitude higher than the production of all other size groups combined, including large copepods. The high loss rates (- 166 to - 271 mg C m- 3 d- 1

  12. Interactive Effects of Temperature and UV Radiation on Photosynthesis of Chlorella Strains from Polar, Temperate and Tropical Environments: Differential Impacts on Damage and Repair.

    PubMed

    Wong, Chiew-Yen; Teoh, Ming-Li; Phang, Siew-Moi; Lim, Phaik-Eem; Beardall, John

    2015-01-01

    Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400-700 nm), PAR plus ultraviolet-A (320-400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280-320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain

  13. Sea Education Association's sailing research vessels as innovative platforms for long-term research and education

    NASA Astrophysics Data System (ADS)

    Joyce, P.; Carruthers, E. A.; Engels, M.; Goodwin, D.; Lavender Law, K. L.; Lea, C.; Schell, J.; Siuda, A.; Witting, J.; Zettler, E.

    2012-12-01

    Sea Education Association's (SEA) two research vessels, the SSV Corwith Cramer and the SSV Robert C. Seamans are unique in the research world. Not only do these ships perform advanced research using state of the art equipment, they do so under sail with high school, undergraduate, and graduate students serving as both the science team and the crew. Because of SEA's educational mission and reliance on prevailing winds for sailing, the vessels have been studying repeated tracks for decades, providing valuable long-term data sets while educating future marine scientists. The Corwith Cramer has been collecting data in the North Atlantic between New England, the Sargasso Sea, Bermuda, and the Caribbean since 1987 while the Robert C. Seamans has been operating in the Eastern Pacific between the US West Coast, Hawaii, and French Polynesia since 2001. The ships collect continuous electronic data from hull mounted ADCP, chirp, and a clean flowing seawater system logging temperature, salinity, in-vivo chlorophyll and CDOM fluorescence, and beam attenuation. The ships also periodically collect data from profiling CTDs with chlorophyll and CDOM fluorometers, transmissometers, and dissolved oxygen and PAR sensors. In addition to electronic data, archived long term data sets include physical samples from net tows such as marine plastic debris and tar, and plankton including Halobates (a marine insect), leptocephali (eel larvae), and phyllosoma (spiny lobster larvae). Both vessels are 134' brigantine rig tall ships and are designated sailing school vessels (SSV) by the US Coast Guard, and both have received instrumentation grants from NSF to provide high quality, reliable data that is submitted to the NSF R2R archives. Students sailing on these ships spend time on shore at the SEA campus in Woods Hole, MA taking classes in oceanography, nautical science, maritime studies and public policy. Each student is required to write a proposal for their research before heading to sea, and

  14. Seasonal variability of hydrographical properties of the Syrian marine water

    NASA Astrophysics Data System (ADS)

    Hussein, Mohammad; Courp, Thierry; Ibrahim, Amir; Benkhelil, Jean

    2011-03-01

    The hydrographical properties of the Syrian marine water are described on the basis of three cruises performed during December 2006, March 2009 and October 2009. In all cruises a Conductivity-Temperature-Depth (CTD) instrument equipped with a fluorometer and oxygen sensor was used for casts that extended to a maximum depth of 480 m. The hydrographic data reveal the presence of Levantine Surface Water (LSW) and Atlantic Water (AW) within the upper 90 m layer, Levantine Intermediate Water (LIW) between 90 and 250 m, and Deep Water (DW) further below. Stratification was clearer in October and December compared to March. Cyclonic and anticyclonic eddies were observed during the three cruises at different locations situated along the Syrian coast. The flow structure along the Syrian coast is controlled by the shape of the coastline and the bottom topography of the continental shelf. From March 2009 to October 2009 a dynamic height rise (within 6 months) of about 3.7-9.8 cm reflected the seasonal cycle of sea level due mainly to thermosteric expansion of the water column. This gave a rise rate in the range of 0.6-1.7 cm month - 1 . Dissolved oxygen was higher in March 2009 (214 ± 4.8 μM) than in December 2006 (202 ± 11.5 μM) or in October 2009 (188 ± 18.9 μM). During March 2009 the water column oxygen distribution was homogeneous. In December 2006 the oxygen distribution was homogeneous in the upper 125 m where LSW was present and subsequently decreased in concentration due to bacterial oxidation of detritus. However, a shallow oxygen maximum (oversaturated) was present at 50-80 m depth during October 2009. Oversaturation was attributed mainly to the biological and physical processes of rapid capping and trapping of oxygen in the AW mass. Chlorophyll- a concentration varied substantially depending on depth and season, having values of 0.05 ± 0.01 mg m - 3 during December 2006, 0.08 ± 0.01 mg m - 3 during March 2009 and 0.06 ± 0.01 mg m - 3 during October 2009

  15. Applications of optical sensors for high-frequency water-quality monitoring and research

    USGS Publications Warehouse

    Pellerin, Brian

    2015-01-01

    The recent commercial availability of in-situ optical sensors, together with new techniques for data collection and analysis, provides the opportunity to monitor a wide range of water-quality constituents over time scales during which environmental conditions actually change. Traditional approaches for data collection (daily to monthly discrete samples) are often limited by high sample collection, processing, and analytical costs, difficult site access, and logistical challenges, particularly for long-term sampling at a large number of sites. Optical sensors that continuously measure constituents in the environment by absorbance or fluorescence properties (Figure 1) have had a long history of use in oceanography for measuring highly resolved concentrations and fluxes of organic matter, nutrients, and algal material. However, much of the work using commercially-available optical sensors in rivers and streams has taken place in only the last few years. Figure 1. [NOT SHOWN] Optical sensor technology is now sufficiently developed to warrant broader application for research and monitoring in coastal and freshwater systems, and the United States Geological Survey (a U.S. science agency) is now using these sensors in a variety of research and monitoring programs to better understand water quality in-situ and in real-time. Examples are numerous and range from the applications of nitrate sensors for calculating loads to estuaries susceptible to hypoxia (Pellerin et al., 2014) to the use of fluorometers to estimate methymercury fluxes (Bergamaschi et al., 2011) and disinfection byproduct formation (Carpenter et al., 2013). Transmitting these data in real-time provides information that can be used for early trend detection, help identify monitoring gaps critical for water management, and provide science-based decision support across a range of issues related to water quality, freshwater ecosystems, and human health. Despite the value of these sensors, collecting data that

  16. Sorption Behavior of Eu(III) into CSH Gel in Imitated Saline Groundwater - 12145

    SciTech Connect

    Funabashi, Taihei; Niibori, Yuichi; Mimura, Hitoshi

    2012-07-01

    The sorption behavior of Eu(III) (europium (III)) into CSH (Calcium Silicate Hydrate) gel without dried processes was examined in imitated saline groundwater by using the spectro-fluorometer, Raman spectrophotometer and ICP-AES (Inductively Coupled Plasma- Atomic Emission Spectrometry). Ca/Si ratio was set to 0.4, 0.8, 1.2 and 1.6, and NaCl concentration was also set to 0.6, 0.06 and 0.006. The synthesis of each sample was conducted in a glove box saturated with nitrogen gas. The sealed sample tubes were gently shaken with 120 strokes/min. The time-period to contact Eu(III) with the CSH gel was set to 60 days. The fluorescence emission spectra suggested the incorporation of Eu{sup 3+} into CSH gel in the high Ca/Si ratio samples. On the other hand, from the decay behavior of fluorescence emission spectra, even in the low Ca/Si ratio samples, sorption behavior of Eu{sup 3+} into CSH gel was confirmed. Besides, the Raman spectra showed that the degree of polymerization of Si-O in CSH gel was raised with increasing Na ions concentration. These results suggest that the CSH gel, formed as secondary mineral, would retard the migration of radionuclides even in saline groundwater. Considering the inflow of saline groundwater into repository, this study examined the interaction between CSH gel (without dry processes) and Eu{sup 3+} by using the fluorescence emission spectra, the decay behavior of fluorescence and the Raman spectra. As a result, the fluorescence emission spectra of the sample of more than 0.8 Ca/Si ratio confirmed the intensity split into two peaks around 618 nm (5D0→7F2 transition). Furthermore, even in relatively low Ca/Si ratio samples, the fluorescence lifetimes both of the surface sorption sample and the co-precipitated samples exceeded that of the filtrate sample. These suggested that Eu{sup 3+} is not only hydrolyzed to form Eu(OH){sub 3} colloid, but is also stably incorporated into CSH gel (in Ca/Si ratio>1.2) or is forming complex on the surface