chlorophyll-a and tetrahydrofuran

Chlorophyll-a (Chl-a) was readily converted into Chl-d under mild conditions without any enzymes. Treatment of Chl-a dissolved in dry tetrahydrofuran (THF) with thiophenol and acetic acid at room temperature successfully produced Chl-d in 31% yield. During the acidic oxidation, removal of the central magnesium, pheophytinization, was sufficiently suppressed. This mild pathway can give insights into the yet unidentified Chl-d biosynthesis.

Topics: Absorption; Acetic Acid; Chlorophyll; Chlorophyll A; Chromatography, High Pressure Liquid; Free Radicals; Furans; In Vitro Techniques; Magnesium; Models, Chemical; Oxidation-Reduction; Oxygen; Phenols; Spinacia oleracea; Sulfhydryl Compounds; Time Factors

The aim of this study was to examine sponge orange band (SOB) disease affecting the prominent Caribbean sponge Xestospongia muta. Scanning and transmission electron microscopy revealed that SOB is accompanied by the massive destruction of the pinacoderm. Chlorophyll a content and the main secondary metabolites, tetrahydrofurans, characteristic of X. muta, were significantly lower in bleached than in healthy tissues. Denaturing gradient gel electrophoresis using cyanobacteria-specific 16S rRNA gene primers revealed a distinct shift from the Synechococcus/Prochlorococcus clade of sponge symbionts towards several clades of unspecific cyanobacteria, including lineages associated with coral disease (i.e. Leptolyngbya sp.). Underwater infection experiments were conducted by transplanting bleached cores into healthy individuals, but revealed no signs of SOB development. This study provided no evidence for the involvement of a specific microbial pathogen as an etiologic agent of disease; hence, the cause of SOB disease in X. muta remains unidentified.

Topics: Animals; Bahamas; Chlorophyll; Chlorophyll A; Chromatography, High Pressure Liquid; Cyanobacteria; Denaturing Gradient Gel Electrophoresis; Florida; Furans; Microscopy, Electron, Scanning; Prochlorococcus; Sequence Analysis, DNA; Spectrophotometry; Symbiosis; Synechococcus; Xestospongia

The binding reaction of methyl pheophorbide-a with bovine serum albumins (BSA) in aqueous solution was studied by fluorescence and UV-Vis absorption spectra. The results indicated that the combination reaction of them was a single static quenching process. In aqueous solution, methyl pheophorbide-a strongly bound BSA with the apparent molar ratio of 2 : 1 because of methyl pheophorbide-a polymerized by itself. The binding constant KB was 6.7 x 10(4) L x mol(-1). In mixture solvent of tetrahydrofuran and water, methyl pheophorbide-a existed as single molecule and bound BSA with a molar ratio of 1: 1. There is single position for combining methyl pheophorbide-a with BSA. The shortest binding distance (r = 3.50 nm) and energy transfer efficiencies (E = 0.39) between donor (BSA) and acceptor (methyl pheophorbide-a) were obtained by Förster's nonradiative energy transfer mechanism.

Topics: Algorithms; Animals; Cattle; Chlorophyll; Energy Transfer; Fluorescence; Furans; Kinetics; Models, Chemical; Molecular Structure; Porphyrins; Protein Binding; Serum Albumin, Bovine; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Water