Project description:Photosynthetic organisms harvest light for energy. Some eukaryotic algae have specialized in harvesting far-red light by tuning chlorophyll a absorption through a mechanism still to be elucidated. Here, we combined optically detected magnetic resonance and pulsed electron paramagnetic resonance measurements on red-adapted light-harvesting complexes, rVCP, isolated from the freshwater eustigmatophyte alga Trachydiscus minutus to identify the location of the pigments responsible for this remarkable adaptation. The pigments have been found to belong to an excitonic cluster of chlorophylls a at the core of the complex, close to the central carotenoids in L1/L2 sites. A pair of structural features of the Chl a403/a603 binding site, namely the histidine-to-asparagine substitution in the magnesium-ligation residue and the small size of the amino acid at the i-4 position, resulting in a [A/G]xxxN motif, are proposed to be the origin of this trait. Phylogenetic analysis of various eukaryotic red antennae identified several potential LHCs that could share this tuning mechanism.
Project description:Regulation of light absorption under variable light conditions is essential to optimize photosynthetic and acclimatory processes in plants. Light energy absorbed in excess has a damaging effect on chloroplasts and can lead to cell death. Therefore, plants have evolved protective mechanisms against excess excitation energy that include chloroplast accumulation and avoidance responses. One of the proteins involved in facilitating chloroplast movements in Arabidopsis thaliana is the J domain-containing protein required for chloroplast accumulation response 1 (JAC1). The function of JAC1 relates to the chloroplast actin filaments appearance and disappearance. So far, the role of JAC1 was studied mainly in terms of chloroplasts photorelocation. Here, we demonstrate that the function of JAC1 is more complex, since it influences the composition of photosynthetic pigments, the efficiency of photosynthesis, and the CO2 uptake rate. JAC1 has positive effect on water use efficiency (WUE) by reducing stomatal aperture and water vapor conductance. Importantly, we show that the stomatal aperture regulation is genetically coupled with JAC1 activity. In addition, our data demonstrate that JAC1 is involved in the fine-tuning of H2O2 foliar levels, antioxidant enzymes activities and cell death after UV-C photooxidative stress. This work uncovers a novel function for JAC1 in affecting photosynthesis, CO2 uptake, and photooxidative stress responses.
Project description:This transcription profiling analysis of Chlorogloeopsis sp. PCC 9212 is designed to study the role of RfpA, RfpB, and RfpC in response to light color change
Project description:Plastid pigment metabolism is an important group of biological processes in senescent leaves. In addition, the pigments provide variegated color and serve as precursors for important flavor compounds. However, the molecular mechanisms of their metabolism and color regulation in postharvest tobacco leaves during the yellowing stage remain elusive. In this study, proteomic analyses involved in carotenoid and chlorophyll metabolism and color regulation were performed.
Project description:Interventions: Linked color imaging (LCI),Endocuff-assisted colonoscopy (EAC),Linked color imaging and Endocuff-assisted colonoscopy (LCI+EAC),Standard white light high-definition colonoscopy;Experimental Device,Experimental Device,Experimental Device,Placebo Comparator Device;Linked color imaging (LCI),Endocuff-assisted colonoscopy (EAC),Linked color imaging and Endocuff-assisted colonoscopy (LCI+EAC),Standard white light high-definition colonoscopy
Primary outcome(s): Adenoma detection rate in each group Crossectional study Adenoma from colonoscopies
Study Design: Randomized
Project description:Fireflies and their fascinating luminous courtships have inspired centuries of scientific study. Today firefly luciferase is widely used in biotechnology, but the evolutionary origin of their bioluminescence remains unclear. To shed light on this long-standing question, we sequenced the genomes of two firefly species that diverged over 100 million-years-ago: the North American Photinus pyralis and Japanese Aquatica lateralis. To compare bioluminescent origins, we also sequenced the genome of a related click-beetle, the Caribbean Ignelater luminosus, with bioluminescent biochemistry near-identical to fireflies, but anatomically unique light organs, suggesting the intriguing but contentious hypothesis of parallel gains of bioluminescence. Our analyses support two independent gains of bioluminescence between fireflies and click-beetles, and provide new insights into the genes, chemical defenses, and symbionts that evolved alongside their luminous lifestyle.
2018-03-22 | GSE107177 | GEO
Project description:The Impact of Artificial Light on Firefly Larvae Transcriptome
Project description:Firefly larvae are highly specialized predators of snails, which utilize midgut secretions to incapacitate and pre-digest their much larger prey. With the current analysis we aim to shed light on the composition of the midgut secretion of these larvae utilizing a proteo-transcriptomic approach.
Project description:Light quality is an important abiotic factor that affects growth and development of photosynthetic organism. In this study, D. salina was exposed to red (660 nm) and blue light (450 nm), and cell growth, pigments, and transcriptome were analyzed. The RNA of D. salina was sequenced and transcriptomic response of algal cells after transitioning from white light to red and blue light was investigated. Genes encoding for enzymes involved in photosynthesis were down-regulated, whereas genes involved in the metabolism of carotenoid were up-regulated. Genes encoding for photoprotective enzymes related to reactive oxygen species scavenging were up-regulated under both red and blue light. The present transcriptomic study would assist in the comprehensive understanding of carotenoid biosynthesis of D. salina.