The sponge Cinachyrella australiensis (Demospongiae: Spirophorida) is widely distributed in Indian ocean, West Pacific ocean, and Australian waters. It also can be found in the intertidal pools of Wun-Li-Ton in southern Taiwan. The sponge can propagate asexually by budding. According to the previous studies, this sponge was suspected to be symbiotic with sulfur-oxidizing chemoautotrophic bacteria. How the generation do obtain this symbiont is still unknow. In this study, PCR was used to amplify the DNA extracted from buds and sponges to obtained the 16S rDNAs. A total of 20 clones from each bud and mature sponge samples were randomly selected and sequenced. The results indicated that the major symbiotic bacteria constitute 65¢H of the clones derived form the mature sponge and 15¢H from the buds. The dominant symbionts contain RubisCO gene and are related to the sulfur-oxidizing chemoautotrophic bacteria, associated with the tube worms of the deep sea hydrothermal vents. The location of the sulfur-oxidizing chemoautotrophic bacteria was observed by fluorescence in situ hybridization (FISH). It was found that the sulfur-oxidizing chemoautotrophic bacteria were intracellular symbiosis within the cells of cortex, archaeocytes of mesoglial, and bud. Similar results were also observed at the junction of a developing bud and mature sponge. Apparently, the symbionts are transmitted from sponge to bud vertically. Furthermore, in this study, we also found several other intracelluar symbionts besides the major symbiotic bacterium,some of them are autotrophic in nature.

A new molecular imaging modality has been developed to detect and locate positive axillary and sentinel lymph nodes non-invasively in breast cancer patients undergoing lymphoscintigraphy. The modality is based on fluorescent photon detection to locate the presence of indocyanine green (ICG) in the lymph subsequent to peritumoral injection of ICG into the breast. The imaging system consists of a gain-modulated intensified charge-coupled device (ICCD) camera, which captures low-intensity, near-infrared, and frequency-modulated photons. A four-fold ‘optical lymphography’ study was conducted to (1) examine fluorescence depth penetration and ICCD system accuracy at clinically relevant depths, (2) compare image quality of the ICCD system vs. conventional gamma imaging, (3) measure ICG pharmacokinetics in vivo, and (4) develop a clinical protocol while examining pre-clinical factors such as the outcome of combining ICG with sulfur colloids used in lymphoscintigraphy. The frequency-domain ICCD system was found to precisely detect modulation amplitude, IAC, and phase, θ, at depths up to 9 cm and with IAC accuracy less than 20% and θ less than 2º using an 80-mW laser incident on phantoms having ranging tissue optical properties. Significant differences in the mean depth of penetration owing to 0.62-ns lifetime and 100-MHz frequency increases were detected. An in vivo optical vs. nuclear image quality comparison demonstrated statistically similar (α=0.05) target-to-background ratios for optical (1.4+/-0.3) and nuclear (1.5+/-0.2). Alternatively, resulting image signal-to-noise ratios (SNR) from the ICCD system were greater than that achieved with a conventional gamma camera (pvalue<<0.01). Analysis of SNR versus contrast showed greater sensitivity of optical over nuclear imaging for subcutaneous tumors. In vivo and rapid detection of ICG in the blood-stream of nude mice was accomplished with a home-built avalanche photodiode dynamic fluorescence measurement system. Intensity data upon i.v. injection were regressed with a pharmacokinetic model describing the partitioning of ICG from the blood to the surrounding tissues. ICG blood-clearance was detected approximately 15 min after injection. Lastly, a human subject protocol was written, practiced, and federally approved for the application of optical lymphography. Furthermore, ICG was unaffected when mixed with sulfur colloids thus supporting the feasibility for combining fluorescence imaging with lymphoscintigraphy in breast cancer patients.

The study of the in vitro circadian oscillator of the cyanobacterium Synechococcus elongatus has uncovered a complex interplay of its three protein components. Synchronization of the clock's central oscillatory component, KaiC, has been thought to be achieved through subunit shuffling at specific intervals during the clock's period. By utilizing an established fluorescence-based analysis on completely phosphorylated and dephosphorylated mutants as well as wild-type KaiC, this study has shown that shuffling rates are largely unaffected by phosphorylation state. These findings conflict with previous reports and hence revise our understanding of this oscillator.

Luminescent conjugated polymers are widely used in organic optoelectronics. The device is fabricated by spin coating the polymer solutions into thin films. It is important to understand the chain conformation in the solution phase, which is mainly determined by the solubility properties of the solutes and the solvents. The purpose of this study is focused on the aggregate structures of MDMO-PPV polymer in the solution mixing of toluene, heptanes, and decahydronaphthalene. Compared to the polymer in toluene solution, the absorption and fluorescence spectra in the mixing solutions are red-shifted, which indicates the aggregation between polymer chains. In order to identify the aggregation is inter-chain or intra-chain effect, we perform concentration dependent measurements of the fluorescence spectra down to 10-10 M. Our results suggest that inter-chain aggregation is the major influence in the concentration. Since the intra-chain aggregation is strongly influenced by polymer concentration, we carry out the experiments to identify how the inter-chain effect influences at even lower concentrations. Fluorescence correlation spectroscopy (FCS) is used to determine the particle size at 10-12M concentration, which relates directly to the aggregation size. The results show that particle size in the poor solution is larger than that in the good solution. Therefore, we conclude that the change of the fluorescence spectra is caused by the inter-chain aggregation even at the concentration to 10-12M.

<p>The focus of this thesis is to explore and use the benefits of time-varying excitation in fluorescence spectroscopy for studies of biomolecular dynamics. Two new techniques taking advantage of modulated excitation are presented. Also described are the first efforts in a project where single molecule FRET and multi-parameter fluorescence detection are used for characterization of the conformational dynamics of the retinoid X receptor (RXR).</p><p>RXR is one of the most important proteins in the group of nuclear receptors. It is believed to be involved in many diseases and is hence most interesting as a potential drug target. Our study is at present at a very early stage and some sample issues are still to be resolved. However, single molecule measurements should give insights not attainable by previously applied ensemble methods and help explaining how RXR can regulate so many different processes.</p><p>Long-lived transient states of fluorescent molecules can, because of their long lifetimes, be used to detect subtle changes in the microenvironment of the molecule. A method for determining the kinetic rates for transitions to and from such states by registration of changes in the average fluorescence intensity related to different modulation of the excitation source is introduced. It combines the sensitivity of fluorescence with the environmental sensitivity of the long-lived transient states and allows the use of slow detectors such as CCD cameras, making parallelization and imaging possible developments. The approach was experimentally verified by measurements of the triplet kinetics of rhodamine 6G (Rh6G) in aqueous solution and compared with fluorescence correlation spectroscopy (FCS). It should also be applicable to any other photoinduced transient states affecting the fluorescence intensity.</p><p>A strategy to combine FCS with modulated excitation, in a way that allows extraction of correlation data for all correlation times, is presented. This enables the use of modulation to optimize the measurement conditions with respect to the photophysical properties of the dyes used. Measurements were made on Rh6G to verify the method. To illustrate its usefulness, it was applied to measurements of protonation kinetics of fluorescein at different pH. FCS with modulated excitation will most probably prove very useful in many future studies involving multiple kinetic processes occurring in overlapping time ranges.</p>

Thèse de doctorat : Environnement et écosystèmes marins et continentaux : Lille 1 : 2001. / N° d'ordre (Lille) : 3089. Résumé et textes en français et en anglais. Bibliogr. p. 155-166. Notes bibliogr.

Reproduction de : Thèse de doctorat : Mécanique de fluides. Énergétique et transferts : Toulouse, INPT : 2004. / Titre provenant de l'écran-titre. Bibliogr. 85 réf.

Thèse de doctorat : Mécanique et énergétique : INPL : 2007. / Titre provenant de l'écran-titre. Bibliogr.

Reproduction de : Thèse de doctorat : Environnement et écosystèmes marins et continentaux : Lille 1 : 2001.

Thèse de doctorat : Génie des procédés et des produits : INPL : 2006. / Titre provenant de l'écran-titre. Bibliogr.