Photoprotection in sequestered plastids of sea slugs and respective algal sources

Some sea slugs are capable of retaining functional sequestered chloroplasts (kleptoplasts) for variable periods of time. The mechanisms supporting the maintenance of these organelles in animal hosts are still largely unknown. Non-photochemical quenching (NPQ) and the occurrence of a xanthophyll cycle were investigated in the sea slugs Elysia viridis and E. chlorotica using chlorophyll fluorescence measurements and pigment analysis. The photoprotective capacity of kleptoplasts was compared to that observed in their respective algal source, Codium tomentosum and Vaucheria litorea. A functional xanthophyll cycle and a rapidly reversible NPQ component were found in V. litorea and E. chlorotica but not in C. tomentosum and E. viridis. To our knowledge, this is the first report of the absence of a functional xanthophyll cycle in a green macroalgae. The absence of a functional xanthophyll cycle in C. tomentosum could contribute to the premature loss of photosynthetic activity and relatively short-term retention of kleptoplasts in E. viridis. On the contrary, E. chlorotica displays one of the longest functional examples of kleptoplasty known so far. We speculate that different efficiencies of photoprotection and repair mechanisms of algal food sources play a role in the longevity of photosynthetic activity in kleptoplasts retained by sea slugs

On the coupling of fluorescence line-narrowing spectroscopy and poly(ethylene)imine-cellulose thin-layer chromatography

The feasibility of a direct coupling of the low-temperature, high- resolution, fluorescence line-narrowing spectroscopy (FLNS) technique and the autoradiographi

Solid phase lanthanide luminescence detection in liquid chromatography

Terbium ions are immobilized on silica gel through ethylenediaminetetraacetic acid (EDTA) or diethylenetriaminepentaacetic acid (DTPA) ligands. The resulting materials are utilized as solid-phase detection systems in liquid chromatography. Terbium(III) luminescence is observed when organic compounds that can transfer energy to Tb(III) by an intramolecular process are present. Peak tailing caused by slow dissociation of transferring compounds from the Tb(III) is significantly reduced if potassium acetate is added to the mobile phase. The solid phases slowly turn a bluish-green color unless triethylenetetraamine is added to the mobile phase. The color change is believed to be caused by bonding of trace amounts of transition metal ions to the solid phase. Detection of carboxylic acid-containing compounds such as indole-2-carboxylic acid, indole-3-acetic acid, 5-methoxyindole-2-carboxylic acid, kynurenic acid, and quinolinic acid is more sensitive with the Tb-DTPA phase than the Tb-EDTA phase, whereas detection of salicylic acid is more sensitive with Tb-EDTA than with Tb-DTPA. The use of time-resolved detection methods significantly enhances the sensitivity. Linearity, reproducibility, limits of detection, and chromatographic separations are examined for several compounds

Pulsed cavity ring-down spectroscopy of NO and NO2 in the exhaust of a running diesel engine

The application of pulsed cavity ring-down spectroscopy has been demonstrated for the in situ quantitative determination of NO and NO2 in the exhaust of a diesel engine. NO absorption has been monitored at the transition from the X²¿ ground state to the A²S+ state at 226 nm. For NO2, absorption bands in the spectral region from 438 nm to 450 nm were used. At the selected engine conditions, concentrations of 212±22 ppm and 29 ± 4 ppm have been measured for NO and NO2, respectively, in good agreement with separate chemical exhaust gas analysis. The method is sensitive enough to meet the European Euro V standard directive on NOx emissions. This communication discusses the relatively simple setup needed for this type of measurement, the problems encountered, as well as the prospects for single-stroke, simultaneous measurements of both NO and NO2 at the sub-ppm level

Pulsed cavity ring-down spectroscopy of NO and NO2 in the exhaust of a running diesel engine

The application of pulsed cavity ring-down spectroscopy has been demonstrated for the in situ quantitative determination of NO and NO2 in the exhaust of a diesel engine. NO absorption has been monitored at the transition from the X²¿ ground state to the A²S+ state at 226 nm. For NO2, absorption bands in the spectral region from 438 nm to 450 nm were used. At the selected engine conditions, concentrations of 212±22 ppm and 29 ± 4 ppm have been measured for NO and NO2, respectively, in good agreement with separate chemical exhaust gas analysis. The method is sensitive enough to meet the European Euro V standard directive on NOx emissions. This communication discusses the relatively simple setup needed for this type of measurement, the problems encountered, as well as the prospects for single-stroke, simultaneous measurements of both NO and NO2 at the sub-ppm level

Measurements of the absolute concentrations of HCO and (CH2)-C-1 in a premixed atmospheric flat flame by cavity ringdown spectroscopy

Singlet methylene (1CH2) and the formyl radical (HCO) have been studied in a premixed flat flame of CH4 and air by cavity ring-down spectroscopy at 1 atm. The absorption lines lie in the same spectral region for both species. The 1CH2 radicals were probed via the 1B1 (0,13,0) ¿ã1A1 (0,0,0) band at 622 nm and the HCO radicals via the Ã2A' (0,9,0) ¿ 2A¿ (0,0,0) band at 615 nm. Absolute concentrations of 1CH2 and HCO have been obtained at various heights above the burner and compared to numerical simulations using both the GRI-Mech 2.11 and 3.0 mechanisms, showing relatively good agreement

Cavity ring down spectroscopy of CH, CH2, HCO, and H2CO in a premixed flat flame at both atmospheric and sub-atmospheric pressure

Density distributions of CH, CH2, HCO and H2CO have been measured in a premixed CH4/air flat flame by Cavity Ring Down Spectroscopy (CRDS). At atmospheric pressure problems are encountered due to the narrow spatial distribution of these species. Rotational flame Temperatures have been derived from the spectral line intensities of CH. Additional distributions of the species are recorded in a low-pressure set up at 2x104 Pa. The results at both pressures are compared to modeling calculations using GRI-Mech 2.11 and 3.0 showing a relatively good agreement. Deviations are attributed to the applied reaction mechanisms