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"Light Physiological effect."
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The darkness manifesto : on light pollution, night ecology, and the ancient rhythms that sustain life
\"In the tradition of Why We Sleep and The Sixth Extinction, an urgent and insightful look at the hidden impact of light pollution, and a passionate appeal to cherish natural darkness for the sake of the environment, our own wellbeing, and all life on earth. How much light is too much light? Satellite pictures show our planet as a brightly glowing orb, and in our era of constant illumination, light pollution has become a major issue. The world's flora and fauna have evolved to operate in the natural cycle of day and night. But in the last 150 years, we have extended our day-and in doing so have forced out the inhabitants of the night and disrupted the circadian rhythms necessary to sustain all living things, including ourselves. In this persuasive, well-researched book, Swedish conservationist Johan Eklöf urges us to appreciate natural darkness, its creatures, and its unique benefits. He ponders the beauties of the night sky, traces the swift dives of keen-eyed owls, and shows us the bioluminescent creatures of the deepest oceans. As a devoted friend of the night, Eklöf reveals the startling domino effect of diminishing darkness: insects, dumbfounded by streetlamps, failing to reproduce; birds blinded and bewildered by artificial lights; and bats starving as they wait in vain for insects that only come out in the dark. For humans, light-induced sleep disturbances impact our hormones and weight, and can exacerbate chronic stress and depression. Streetlamps, floodlights, and the ever more pervasive and searingly bright LED lights are altering entire ecosystems, and scientists are only just beginning to understand the long-term effects. Educational, eye-opening, and ultimately encouraging, The Darkness Manifesto outlines simple steps that we can take to benefit ourselves and the planet. In order to ensure a bright future, we must embrace the darkness\"-- Provided by publisher.
Book
Life under the sun
Which fungus is as sensitive to light as the human eye? What are the myths and facts about the ozone hole, tanning, skin cancer, and sunscreens? What is the effect of light on butterfly copulation? This entertaining collection of essays explores how various organisms-including archaebacteria, slime molds, fungi, plants, insects, and humans-sense and respond to sunlight.The essays in Peter A. Ensminger's book cover vision, photosynthesis, and phototropism, as well as such unusual topics as the reason why light causes beer to develop a \"skunky\" odor. He introduces us to the kinds of eyes that have evolved in different animals, including those in a species of shrimp that is ostensibly eyeless; gives us a better appreciation of color vision; explains how plowing fields at night may be used to control weeds; and tells about variegate porphyria, a metabolic disease that makes people very sensitive to sunlight and may have afflicted King George III of England.These engaging essays present a complicated yet fascinating subject in an accessible way. The book will be treasured by anyone interested in the wonders of biology.
eBook
Color Psychology And Color Therapy; A Factual Study Of The Influence of Color On Human Life
A detailed study of the various sources and biological and emotional uses of color in all phases of human existence by a leading researcher in the field.
eBook
Chromic phenomena
Chromic phenomena, or those produced by materials which exhibit colour in response to a chemical or physical stimulus, have increasingly been at the heart of 'high-tec' developments in a variety of fields in the last decade. Many of the newer technologies, which are at the cutting edge of research, are multi-disciplinary, involving researchers from areas as diverse as physics, biology, materials science and electronic engineering.
Chromic Phenomena covers five main areas:
* Colour change materials, such as photochromic, thermochromic and electrochromic materials
* Materials which absorb and reflect light - the classical dyes and pigments
* Luminescent phenomena, including phosphorescence, fluorescence and electroluminescence
* Materials which absorb light and transfer energy, eg photosensitisers, infra-red absorbers and laser-addressable compounds
* Phenomena involving the manipulation of light by chemicals, such as liquid crystals, lustre pigments, optoelectronics and photonics
Providing an entry point both for new researchers and for established ones, this book, with its emphasis on the technological applications of these chromic phenomena, develops and investigates new applications for colour chemistry. It will be of interest to industrialists and professionals in the biological, medicinal, electronics/telecommunications and colorant industries, as well as academics in these fields.
eBook
A blue-light photoreceptor mediates the feedback regulation of photosynthesis
In plants and algae, light serves both as the energy source for photosynthesis and a biological signal that triggers cellular responses via specific sensory photoreceptors. Red light is perceived by bilin-containing phytochromes and blue light by the flavin-containing cryptochromes and/or phototropins (PHOTs), the latter containing two photosensory light, oxygen, or voltage (LOV) domains. Photoperception spans several orders of light intensity, ranging from far below the threshold for photosynthesis to values beyond the capacity of photosynthetic CO2 assimilation. Excess light may cause oxidative damage and cell death, processes prevented by enhanced thermal dissipation via high-energy quenching (qE), a key photoprotective response. Here we show the existence of a molecular link between photoreception, photosynthesis, and photoprotection in the green alga Chlamydomonas reinhardtii. We show that PHOT controls qE by inducing the expression of the qE effector protein LHCSR3 (light-harvesting complex stress-related protein 3) in high light intensities. This control requires blue-light perception by LOV domains on PHOT, LHCSR3 induction through PHOT kinase, and light dissipation in photosystem II via LHCSR3. Mutants deficient in the PHOT gene display severely reduced fitness under excessive light conditions, indicating that the sensing, utilization, and dissipation of light is a concerted process that plays a vital role in microalgal acclimation to environments of variable light intensities.
Journal Article
Enhanced seed production under prolonged heat stress conditions in Arabidopsis thaliana plants deficient in cytosolic ascorbate peroxidase 2
Reactive oxygen species play a key role in the response of plants to abiotic stress conditions. Their level is controlled in Arabidopsis thaliana by a large network of genes that includes the H2O2-scavenging enzymes cytosolic ascorbate peroxidase (APX) 1 and 2. Although the function of APX1 has been established under different growth conditions, genetic evidence for APX2 function, as well as for the mode of cooperation between APX1 and APX2, is very limited. This study characterized the response of Arabidopsis mutants deficient in APX1, APX2, and APX1/APX2 to heat, salinity, light, and oxidative stresses. The findings reveal that deficiency in APX2 resulted in a decreased tolerance to light stress, as well as an enhanced tolerance to salinity and oxidative stresses. Interestingly, plants lacking APX2 were more sensitive to heat stress at the seedling stage, but more tolerant to heat stress at the reproductive stage. Cooperation between APX1 and APX2 was evident during oxidative stress, but not during light, salinity, or heat stress. The findings demonstrate a role for APX2 in the response of plants to light, heat, salinity, and oxidative stresses. The finding that plants lacking APX2 produced more seeds under prolonged heat stress conditions suggests that redundant mechanisms activated in APX2-deficient plants during heat stress play a key role in the protection of reproductive tissues from heat-related damage. This finding is very important because heat-associated damage to reproductive tissues in different crops is a major cause for yield loss in agriculture production worldwide.
Journal Article
FAR-RED ELONGATED HYPOCOTYL3 and FAR-RED IMPAIRED RESPONSE1 Transcription Factors Integrate Light and Abscisic Acid Signaling in Arabidopsis
Light and the phytohormone abscisic acid (ABA) regulate overlapping processes in plants, such as seed germination and seedling development. However, the molecular mechanism underlying the interaction between light and ABA signaling is largely unknown. Here, we show that FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and FAR-RED IMPAIRED RESPONSE1 (FAR1), two key positive transcription factors in the phytochrome A pathway, directly bind to the promoter of ABA-Insensitive5 and activate its expression in Arabidopsis (Arabidopsis thaliana). Disruption of FHY3 and/or FAR1 reduces the sensitivity to ABA-mediated inhibition of seed germination, seedling development, and primary root growth. The seed germination of the fhy3 mutant is also less sensitive to salt and osmotic stress than that of the wild type. Constitutive expression of ABA-Insensitive5 restores the seed germination response of fhy3. Furthermore, the expression of several ABA-responsive genes is decreased in the fhy3 and/or far1 mutants during seed imbibition. Consistently, FHY3 and FAR1 transcripts are up-regulated by ABA and abiotic stresses. Moreover, the fhy3 and far1 mutants have wider stomata, lose water faster, and are more sensitive to drought than the wild type. These findings demonstrate that FHY3 and FAR1 are positive regulators of ABA signaling and provide insight into the integration of light and ABA signaling, a process that may allow plants to better adapt to environmental stresses.
Journal Article
Chloroplastic biosynthesis of melatonin and its involvement in protection of plants from salt stress
Within the chloroplasts reactive oxygen species (ROS) are generated during photosynthesis and stressful conditions. Excessive ROS damages chloroplasts and reduces photosynthesis if not properly detoxified. In this current study, we document that chloroplasts produce melatonin, a recently-discovered plant antioxidant molecule. When
N
-acetylserotonin, a substrate for melatonin synthesis, was fed to purified chloroplasts, they produced melatonin in a dose-response manner. To further confirm this function of chloroplasts, the terminal enzyme for melatonin synthesis, N-acetylserotonin-O-methyltransferase (ASMT), was cloned from apple rootstock,
Malus zumi.
The
in vivo
fluorescence observations and Western blots confirmed MzASMT9 was localized in the chloroplasts. A study of enzyme kinetics revealed that the
K
m
and
V
max
of the purified recombinant MzASMT9 protein for melatonin synthesis were 500 μM and 12 pmol/min·mg protein, respectively.
Arabidopsis
ectopically-expressing
MzASMT9
possessed improved melatonin level. Importantly, the
MzASMT9
gene was found to be upregulated by high light intensity and salt stress. Increased melatonin due to the highly-expressed
MzASMT9
resulted in
Arabidopsis
lines with enhanced salt tolerance than wild type plants, as indicated by reduced ROS, lowered lipid peroxidation and enhanced photosynthesis. These findings have agricultural applications for the genetic enhancement of melatonin-enriched plants for increasing crop production under a variety of unfavorable environmental conditions.
Journal Article
Sensory pollutants alter bird phenology and fitness across a continent
Expansion of anthropogenic noise and night lighting across our planet
1
,
2
is of increasing conservation concern
3
–
6
. Despite growing knowledge of physiological and behavioural responses to these stimuli from single-species and local-scale studies, whether these pollutants affect fitness is less clear, as is how and why species vary in their sensitivity to these anthropic stressors. Here we leverage a large citizen science dataset paired with high-resolution noise and light data from across the contiguous United States to assess how these stimuli affect reproductive success in 142 bird species. We find responses to both sensory pollutants linked to the functional traits and habitat affiliations of species. For example, overall nest success was negatively correlated with noise among birds in closed environments. Species-specific changes in reproductive timing and hatching success in response to noise exposure were explained by vocalization frequency, nesting location and diet. Additionally, increased light-gathering ability of species’ eyes was associated with stronger advancements in reproductive timing in response to light exposure, potentially creating phenological mismatches
7
. Unexpectedly, better light-gathering ability was linked to reduced clutch failure and increased overall nest success in response to light exposure, raising important questions about how responses to sensory pollutants counteract or exacerbate responses to other aspects of global change, such as climate warming. These findings demonstrate that anthropogenic noise and light can substantially affect breeding bird phenology and fitness, and underscore the need to consider sensory pollutants alongside traditional dimensions of the environment that typically inform biodiversity conservation.
Human-generated noise and night lighting affect breeding habits and fitness in birds, implying that sensory pollutants must be considered alongside other environmental factors in assessing biodiversity conservation.
Journal Article