RESUMO
We have cloned a novel fluorescent protein from the jellyfish Rhacostoma atlantica. The closest known related fluorescent protein is the Phialidium yellow fluorescent protein, with only a 55% amino acid sequence identity. A somewhat unusual alanine-tyrosine-glycine amino acid sequence forms the presumed chromophore of the novel protein. The protein has an absorption peak at 466 nm and a fluorescence emission peak at 498 nm. The fluorescence quantum yield was measured to be 0.77 and the extinction coefficient is 58 200 M(-1) cm(-1) . Several mutations were identified that shift the absorption peak to about 494 nm and the emission peak to between 512 and 514 nm.
Assuntos
Proteínas Luminescentes/química , Proteínas Luminescentes/genética , Cifozoários/química , Cifozoários/genética , Animais , Clonagem Molecular , Proteínas Luminescentes/metabolismoRESUMO
Marine sponges are major habitat-forming organisms in coastal benthic communities and have an ancient origin in evolution history. Here, we report significant accumulation of polyphosphate (polyP) granules in three common sponge species of the Caribbean coral reef. The identity of the polyP granules was confirmed by energy-dispersive spectroscopy (EDS) and by the fluorescence properties of the granules. Microscopy images revealed that a large proportion of microbial cells associated with sponge hosts contained intracellular polyP granules. Cyanobacterial symbionts cultured from sponges were shown to accumulate polyP. We also amplified polyphosphate kinase (ppk) genes from sponge DNA and confirmed that the gene was expressed. Based on these findings, we propose here a potentially important phosphorus (P) sequestration pathway through symbiotic microorganisms of marine sponges. Considering the widespread sponge population and abundant microbial cells associated with them, this pathway is likely to have a significant impact on the P cycle in benthic ecosystems.
Assuntos
Cianobactérias/metabolismo , Fósforo/fisiologia , Poríferos/microbiologia , Simbiose , Animais , Proteínas de Bactérias , Biodiversidade , Recifes de Corais , Ecossistema , Florida , Proteínas Luminescentes , Microscopia Confocal , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Dados de Sequência Molecular , Fósforo/química , Polifosfatos/química , RNA Ribossômico 16S/genética , Especificidade da EspécieRESUMO
We describe a fundamental observation in Metal-Enhanced Fluorescence (MEF), which has become a leading technology in the life sciences today, namely, how the lifetime of fluorophores near-to metallic plasmon-supporting silver islands/nanoparticles, modulates as a function of excitation power irradiance. This finding is in stark contrast to that observed in classical far-field fluorescence spectroscopy, where excitation power does not influence fluorophore radiative decay/lifetime.