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Scientific Reports Nov 2016In optogenetics, researchers use light and genetically encoded photoreceptors to control biological processes with unmatched precision. However, outside of neuroscience,...
In optogenetics, researchers use light and genetically encoded photoreceptors to control biological processes with unmatched precision. However, outside of neuroscience, the impact of optogenetics has been limited by a lack of user-friendly, flexible, accessible hardware. Here, we engineer the Light Plate Apparatus (LPA), a device that can deliver two independent 310 to 1550 nm light signals to each well of a 24-well plate with intensity control over three orders of magnitude and millisecond resolution. Signals are programmed using an intuitive web tool named Iris. All components can be purchased for under $400 and the device can be assembled and calibrated by a non-expert in one day. We use the LPA to precisely control gene expression from blue, green, and red light responsive optogenetic tools in bacteria, yeast, and mammalian cells and simplify the entrainment of cyanobacterial circadian rhythm. The LPA dramatically reduces the entry barrier to optogenetics and photobiology experiments.
Topics: Calibration; Circadian Rhythm; Equipment Design; Gene Expression; Green Fluorescent Proteins; HeLa Cells; Humans; Light; Models, Theoretical; Optogenetics; Photobiology; Saccharomyces cerevisiae; Synechococcus; Tissue Engineering; Two-Hybrid System Techniques
PubMed: 27805047
DOI: 10.1038/srep35363 -
Plant Physiology Sep 2015The VQ motif-containing proteins (designated as VQ proteins) are a class of plant-specific proteins with a conserved and single short FxxhVQxhTG amino acid sequence... (Review)
Review
The VQ motif-containing proteins (designated as VQ proteins) are a class of plant-specific proteins with a conserved and single short FxxhVQxhTG amino acid sequence motif. VQ proteins regulate diverse developmental processes, including responses to biotic and abiotic stresses, seed development, and photomorphogenesis. In this Update, we summarize and discuss recent advances in our understanding of the regulation and function of VQ proteins and the role of the VQ motif in mediating transcriptional regulation and protein-protein interactions in signaling pathways. Based on the accumulated evidence, we propose a general mechanism of action for the VQ protein family, which likely defines a novel class of transcriptional regulators specific to plants.
Topics: Amino Acid Motifs; Amino Acid Sequence; Arabidopsis; Arabidopsis Proteins; Molecular Sequence Data; Species Specificity; Stress, Physiological; Transcription Factors
PubMed: 26220951
DOI: 10.1104/pp.15.00788 -
Microbiology Spectrum May 2017The capacity for biological timekeeping arose at least three times through evolution, in prokaryotic cyanobacteria, in cells that evolved into higher plants, and within... (Review)
Review
The capacity for biological timekeeping arose at least three times through evolution, in prokaryotic cyanobacteria, in cells that evolved into higher plants, and within the group of organisms that eventually became the fungi and the animals. is a tractable model system for understanding the molecular bases of circadian rhythms in the last of these groups, and is perhaps the most intensively studied circadian cell type. Rhythmic processes described in fungi include growth rate, stress responses, developmental capacity, and sporulation, as well as much of metabolism; fungi use clocks to anticipate daily environmental changes. A negative feedback loop comprises the core of the circadian system in fungi and animals. In , the best studied fungal model, it is driven by two transcription factors, WC-1 and WC-2, that form the White Collar Complex (WCC). WCC elicits expression of the gene. FRQ complexes with other proteins, physically interacts with the WCC, and reduces its activity; the kinetics of these processes is strongly influenced by progressive phosphorylation of FRQ. When FRQ becomes sufficiently phosphorylated that it loses the ability to influence WCC activity, the circadian cycle starts again. Environmental cycles of light and temperature influence and FRQ expression and thereby reset the internal circadian clocks. The molecular basis of circadian output is also becoming understood. Taken together, molecular explanations are emerging for all the canonical circadian properties, providing a molecular and regulatory framework that may be extended to many members of the fungal and animal kingdoms, including humans.
Topics: Animals; Biological Clocks; Circadian Rhythm; DNA-Binding Proteins; Feedback, Physiological; Fungal Proteins; Fungi; Gene Expression Regulation, Fungal; Genes, Fungal; Humans; Light; Models, Biological; Neurospora; Photobiology; Temperature; Transcription Factors; Transcription, Genetic
PubMed: 28527179
DOI: 10.1128/microbiolspec.FUNK-0039-2016 -
Environmental Health Perspectives Mar 2000Sunscreens are ultraviolet radiation (UVR)-absorbing chemicals that attenuate the amount and nature of UVR reaching viable cells in the skin. They are selected and... (Review)
Review
Sunscreens are ultraviolet radiation (UVR)-absorbing chemicals that attenuate the amount and nature of UVR reaching viable cells in the skin. They are selected and tested for their ability to prevent erythema. No sunscreen prevents photodamage, as it has been demonstrated that suberythemal doses of UVR cause a variety of molecular changes (including DNA damage) in these cells. Furthermore, the spectrum of UVR reaching viable cells is altered by topically applied sunscreen. In this review, the basic aspects of sunscreens and skin photobiology are reviewed briefly. Although there can be no question concerning the efficacy of sunscreens for the prevention of erythema, questions remain because of the possible cumulative effects of chronic suberythemal doses and the increased exposure of skin cells to longer UVR wavelengths. The current major issue surrounding sunscreens involves their ability to protect skin cells against the effects of UVA radiation. These UVA effects may be direct damage (base oxidations) or effects on the skin immune system, yet there is no uniformly accepted method for the evaluation of UVA protection. This review is focused primarily on the latter topic covering action spectra that implicate the need for UVA protection. In addition, in vivo and in vitro methods proposed for the evaluation of candidate sunscreen formulations of UVA protective ability are reviewed. Finally, revisions in the terminology used to describe the protection afforded by sunscreens are suggested. It is proposed that SPF ("sun" protection factor) be renamed "sunburn" protection factor and that "critical wavelength" be designated "long wave index."
Topics: Animals; Humans; Photobiology; Skin; Skin Neoplasms; Sunscreening Agents; Ultraviolet Rays
PubMed: 10698724
DOI: 10.1289/ehp.00108s171 -
Journal of Dermatological Science Jan 2009The hairless (Hr) gene encodes a transcriptional co-repressor highly expressed in the mammalian skin. In the mouse, several null and hypomorphic Hr alleles have been... (Review)
Review
The hairless (Hr) gene encodes a transcriptional co-repressor highly expressed in the mammalian skin. In the mouse, several null and hypomorphic Hr alleles have been identified resulting in hairlessness in homozygous animals, characterized by alopecia developing after a single cycle of relatively normal hair growth. Mutations in the human ortholog have also been associated with congenital alopecia. Although a variety of hairless strains have been developed, outbred SKH1 mice are the most widely used in dermatologic research. These unpigmented and immunocompetent mice allow for ready manipulation of the skin, application of topical agents, and exposure to UVR, as well as easy visualization of the cutaneous response. Wound healing, acute photobiologic responses, and skin carcinogenesis have been extensively studied in SKH1 mice and are well characterized. In addition, tumors induced in these mice resemble, both at the morphologic and molecular levels, UVR-induced skin malignancies in man. Two limitations of the SKH1 mouse in dermatologic research are the relatively uncharacterized genetic background and its outbred status, which precludes inter-individual transplantation studies.
Topics: Animals; Disease Models, Animal; Histocompatibility; Mice; Mice, Hairless; Photobiology; Research Design; Skin Diseases; Skin Neoplasms; Wound Healing
PubMed: 18938063
DOI: 10.1016/j.jdermsci.2008.08.012 -
FEBS Letters May 2007"Osmotic Motors"--the best-documented explanation for plant leaf movements--frequently reside in specialized motor leaf organs, pulvini. The movements result from... (Review)
Review
"Osmotic Motors"--the best-documented explanation for plant leaf movements--frequently reside in specialized motor leaf organs, pulvini. The movements result from dissimilar volume and turgor changes in two oppositely positioned parts of the pulvinus. This Osmotic Motor is powered by a plasma membrane proton ATPase, which drives KCl fluxes and, consequently, water, across the pulvinus into swelling cells and out of shrinking cells. Light signals and signals from the endogenous biological clock converge on the channels through which these fluxes occur. These channels and their regulatory pathways in the pulvinus are the topic of this review.
Topics: Aquaporins; Circadian Rhythm; Models, Biological; Molecular Motor Proteins; Movement; Photobiology; Plant Leaves; Plant Proteins; Potassium Channels; Potassium Chloride; Pulvinus; Signal Transduction; Water-Electrolyte Balance
PubMed: 17434488
DOI: 10.1016/j.febslet.2007.04.002 -
Philosophical Transactions of the Royal... Sep 1998Plants have evolved exquisite sensory systems for monitoring their light environment. The intensity, quality, direction and duration of light are continuously monitored... (Review)
Review
Plants have evolved exquisite sensory systems for monitoring their light environment. The intensity, quality, direction and duration of light are continuously monitored by the plant and the information gained is used to modulate all aspects of plant development. Several classes of distinct photoreceptors, sensitive to different regions of the light spectrum, mediate the developmental responses of plants to light signals. The red-far-red light-absorbing, reversibly photochromic phytochromes are perhaps the best characterized of these. Higher plants possess a family of phytochromes, the apoproteins of which are encoded by a small, divergent gene family. Arabidopsis has five apophytochrome-encoding genes, PHYA-PHYE. Different phytochromes have discrete biochemical and physiological properties, are differentially expressed and are involved in the perception of different light signals. Photoreceptor and signal transduction mutants of Arabidopsis are proving to be valuable tools in the molecular dissection of photomorphogenesis. Mutants deficient in four of the five phytochromes have now been isolated. Their analysis indicates considerable overlap in the physiological functions of different phytochromes. In addition, mutants defining components acting downstream of the phytochromes have provided evidence that different members of the family use different signalling pathways.
Topics: Arabidopsis; Genes, Plant; Light; Mutation; Photobiology; Photosynthetic Reaction Center Complex Proteins; Phytochrome; Signal Transduction
PubMed: 9800208
DOI: 10.1098/rstb.1998.0300 -
The New Phytologist May 2018
Topics: Botany; History, 20th Century; History, 21st Century; Light; Plants
PubMed: 29658635
DOI: 10.1111/nph.15132 -
Photodermatology, Photoimmunology &... Mar 2022One early problem during the height of the COVID-19 global pandemic, caused by severe acute respiratory syndrome 2 (SARS-CoV-2), was the shortage of personal protective... (Review)
Review
One early problem during the height of the COVID-19 global pandemic, caused by severe acute respiratory syndrome 2 (SARS-CoV-2), was the shortage of personal protective equipment donned by healthcare workers, particularly N95 respirators. Given the known virucidal, bactericidal, and fungicidal properties of ultraviolet irradiation, in particular ultraviolet C (UVC) radiation, our photomedicine and photobiology unit explored the role of ultraviolet germicidal irradiation (UVGI) using UVC in effectively decontaminating N95 respirators. The review highlights the important role of photobiology and photomedicine in this pandemic. Namely, the goals of this review were to highlight: UVGI as a method of respirator disinfection-specifically against SARS-CoV-2, adverse reactions to UVC and precautions to protect against exposure, other methods of decontamination of respirators, and the importance of respirator fit testing.
Topics: COVID-19; Decontamination; Equipment Reuse; Global Health; Humans; N95 Respirators; Pandemics; SARS-CoV-2; Ultraviolet Rays
PubMed: 34467568
DOI: 10.1111/phpp.12729 -
American Journal of Botany Dec 2014Investigation of the red bread mold that contaminated French bakeries nearly two centuries ago has led to a wealth of discoveries that have impacted our understanding of... (Review)
Review
Investigation of the red bread mold that contaminated French bakeries nearly two centuries ago has led to a wealth of discoveries that have impacted our understanding of genetic, biochemical, and molecular mechanisms in microbes, from Mendelian genetics and the gene-enzyme relationship to circadian rhythm and plant cell wall degradation. Early Neurospora research focused on elucidating mechanisms of genetic recombination and gene action and later progressed to addressing complex biological questions of eukaryotic microbes. Here we review the evolution of the filamentous fungus Neurospora as a model microbe over the past century. We discuss the origins of Neurospora as a model microbe, the immediate scientific impacts from work in this filamentous fungus, and how the introduction of other model organisms (i.e., Escherichia coli and Saccharomyces cerevisiae) redirected the focus of Neurospora research. Neurospora has and continues to inform our understanding of a myriad of basic scientific concepts and now has the opportunity to forge into the applied biosciences and biotechnology.
Topics: Models, Biological; Neurospora crassa
PubMed: 25480699
DOI: 10.3732/ajb.1400377