A5074877571- Circadian rhythm and melatonin
- Light effects on plants
- Photosynthetic Processes and Mechanisms
- Photoreceptor and optogenetics research
- Algal biology and biofuel production
- Spaceflight effects on biology
- bioluminescence and chemiluminescence research
- Protist diversity and phylogeny
- Plant and Biological Electrophysiology Studies
- Biocrusts and Microbial Ecology
- Genetics, Aging, and Longevity in Model Organisms
- Advanced Fluorescence Microscopy Techniques
- Dietary Effects on Health
- Epigenetics and DNA Methylation
- Plant Molecular Biology Research
- Microbial Community Ecology and Physiology
- Marine and coastal plant biology
- Plant and animal studies
- Microbial Metabolic Engineering and Bioproduction
- Genetic Syndromes and Imprinting
- Nonlinear Dynamics and Pattern Formation
- Biotin and Related Studies
- Genetics and Neurodevelopmental Disorders
- Mitochondrial Function and Pathology
- Advanced Thermodynamics and Statistical Mechanics
Vanderbilt University
2015-2024
Vanderbilt Health
2017
Institute of Molecular Biology and Biophysics
2014
Vanderbilt University Medical Center
2014
Society for Research on Biological Rhythms
2013
Zero to Three
2012
Children's National
2011
Saint Ambrose University
2009
Harvard University
1983-2008
National and Kapodistrian University of Athens
2008
In some organisms longevity, growth, and developmental rate are improved when they maintained on a light/dark cycle, the period of which “resonates” optimally with endogenous circadian clock. However, to our knowledge no studies have demonstrated that reproductive fitness per se is by resonance between clock environmental cycle. We tested adaptive significance programming measuring relative under competition various strains cyanobacteria expressing different periods. Strains had similar...
Cyanobacteria are the simplest organisms known to have a circadian clock. A clock gene cluster kaiABC was cloned from cyanobacterium Synechococcus. Nineteen mutations were mapped three kai genes. Promoter activities upstream of kaiA and kaiB genes showed rhythms expression, both kaiBC messenger RNAs displayed cycling. Inactivation any single abolished these reduced -promoter activity. Continuous kaiC overexpression repressed promoter, whereas enhanced it. Temporal reset phase rhythms. Thus,...
We describe a method for assaying protein interactions that offers some attractive advantages over previous assays. This method, called bioluminescence resonance energy transfer (BRET), uses bioluminescent luciferase is genetically fused to one candidate protein, and green fluorescent mutant another of interest. Interactions between the two fusion proteins can bring close enough occur, thus changing color emission. By using encoded by circadian (daily) clock genes from cyanobacteria, we use...
We have used a luciferase reporter gene and continuous automated monitoring of bioluminescence to demonstrate unequivocally that cyanobacteria exhibit circadian behaviors are fundamentally the same as rhythms eukaryotes. also show these can be studied by molecular methods in Synechococcus sp. PCC7942, strain for which genetic transformation is well established. A promoterless segment Vibrio harveyi structural genes (luxAB) was introduced downstream promoter psbAI gene, encodes photosystem II...
Genome biology approaches have made enormous contributions to our understanding of biological rhythms, particularly in identifying outputs the clock, including RNAs, proteins, and metabolites, whose abundance oscillates throughout day. These methods hold significant promise for future discovery, when combined with computational modeling. However, genome-scale experiments are costly laborious, yielding “big data” that conceptually statistically difficult analyze. There is no obvious consensus...
Surely most chronobiologists believe circadian clocks are an adaptation of organisms that enhances fitness, but we certain this focus our research effort really confers a fitness advantage? What is the evidence, and how do evaluate it? best criteria? These questions topic review. In addition, will discuss selective pressures might have led to historical evolution systems while considering intriguing question whether ongoing climate change modulating these so clock still evolving.
We wanted to identify genes that are controlled by the circadian clock in prokaryotic cyanobacterium Synechococcus sp. strain PCC 7942. To use luciferase as a reporter monitor gene expression, bacterial (luxAB) were inserted randomly into genome conjugation with Escherichia coli and subsequent homologous recombination. The resulting transformed clones then screened for bioluminescence using new developed cooled-CCD camera system. approximately 30,000 colonies recovered 800 whose was bright...
Tobacco and Arabidopsis plants, expressing a transgene for the calcium-sensitive luminescent protein apoaequorin, revealed circadian oscillations in free cytosolic calcium that can be phase-shifted by light-dark signals. When apoaequorin was targeted to chloroplast, chloroplast rhythms were likewise observed after transfer of seedlings constant darkness. Circadian concentrations expected control many calcium-dependent enzymes processes accounting outputs. Regulation flux is therefore...
To ascertain whether the circadian oscillator in prokaryotic cyanobacterium Synechococcus PCC 7942 regulates timing of cell division rapidly growing cultures, we measured rate division, DNA content, size, and gene expression (monitored by luminescence PpsbAI::luxAB reporter) cultures that were continuously diluted to maintain an approximately equal density. We found populations dividing at rates as rapid once per 10 h manifest gating since phases which slows or stops recur with a...
A diverse set of circadian clock mutants was isolated in a cyanobacterial strain that carries bacterial luciferase reporter gene attached to clock-controlled promoter. Among 150,000 clones chemically mutagenized bioluminescent cells, 12 were exhibit broad spectrum periods (between 16 and 60 hours), 5 found show variety unusual patterns, including arrhythmia. These mutations appear be clock-specific. Moreover, it demonstrated this cyanobacterium is possible clone mutant genes by...
Evidence from a number of laboratories over the past 12 years has established that cyanobacteria, group photosynthetic eubacteria, possess circadian pacemaker controls metabolic and genetic functions. The cyanobacterial clock exhibits three intrinsic properties have come to define clocks eukaryotes: timekeeping mechanism rhythms show period about 24 h in absence external signals, phase can be reset by light/dark cues, is relatively insensitive temperature. promise cyanobacteria as simple...
Background Daily cycles of sleep/wake, hormones, and physiological processes are often misaligned with behavioral patterns during shift work, leading to an increased risk developing cardiovascular/metabolic/gastrointestinal disorders, some types cancer, mental disorders including depression anxiety. It is unclear how sleep timing, chronotype, circadian clock gene variation contribute adaptation work. Methods Newly defined strategies, genotype for polymorphisms in genes were assessed 388...
REVIEW article Front. Endocrinol., 07 August 2013 | https://doi.org/10.3389/fendo.2013.00092