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https://www.readbyqxmd.com/read/28199106/mechanistic-studies-of-the-photoinduced-quinone-trimethyl-lock-decaging-process
#1
Clinton J Regan, David P Walton, Oliver S Shafaat, Dennis A Dougherty
Mechanistic studies of a general reaction that decages a wide range of substrates on exposure to visible light are described. The reaction involves a photochemically initiated reduction of a quinone mediated by an appended thioether. After reduction, a trimethyl lock system incorporated into the quinone leads to decaging. The reaction could be viewed as an electron-transfer initiated reduction of the quinone or as a hydrogen abstraction - Norrish Type II - reaction. Product analysis, kinetic isotope effects, stereochemical labeling, radical clock, and transient absorption studies support the electron transfer mechanism...
February 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28186138/the-spectral-and-spatial-distribution-of-light-pollution-in-the-waters-of-the-northern-gulf-of-aqaba-eilat
#2
Raz Tamir, Amit Lerner, Carynelisa Haspel, Zvy Dubinsky, David Iluz
The urbanization of the shores of the Gulf of Aqaba has exposed the marine environment there, including unique fringing coral reefs, to strong anthropogenic light sources. Here we present the first in situ measurements of artificial nighttime light under water in such an ecosystem, with irradiance measured in 12 wavelength bands, at 19 measurement stations spread over 44 square km, and at 30 depths down to 30-m depth. At 1-m depth, we find downwelling irradiance values that vary from 4.6 × 10(-4) μW cm(-2) nm(-1) 500 m from the city to 1 × 10(-6) μW cm(-2) nm(-1) in the center of the gulf (9...
February 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28185583/probabilistic-inference-of-lateral-gene-transfer-events
#3
Mehmood Alam Khan, Owais Mahmudi, Ikram Ullah, Lars Arvestad, Jens Lagergren
BACKGROUND: Lateral gene transfer (LGT) is an evolutionary process that has an important role in biology. It challenges the traditional binary tree-like evolution of species and is attracting increasing attention of the molecular biologists due to its involvement in antibiotic resistance. A number of attempts have been made to model LGT in the presence of gene duplication and loss, but reliably placing LGT events in the species tree has remained a challenge. RESULTS: In this paper, we propose probabilistic methods that samples reconciliations of the gene tree with a dated species tree and computes maximum a posteriori probabilities...
November 11, 2016: BMC Bioinformatics
https://www.readbyqxmd.com/read/28185343/birth-and-death-evidence-for-the-same-biologic-clock
#4
Mark Phillippe, Shiela M Phillippe
In mammals, there exists a strong correlation between the average life span (in years) and the length of gestation (in days), suggesting that the same biologic clock mechanisms control both of these physiologic events. Life span is determined by a complex sequence of events leading to organismal senescence, and ultimately death. Although multiple biochemical and cellular phenomena are believed to be involved, progressive telomere shortening due to oxidative stress and loss during DNA replication is believed to be an important determinant contributing to aging, senescence, and adult death...
February 10, 2017: American Journal of Reproductive Immunology: AJRI
https://www.readbyqxmd.com/read/28165421/circadian-rhythms-and-hormonal-homeostasis-pathophysiological-implications
#5
REVIEW
Davide Gnocchi, Giovannella Bruscalupi
Over recent years, a deeper comprehension of the molecular mechanisms that control biological clocks and circadian rhythms has been achieved. In fact, many studies have contributed to unravelling the importance of the molecular clock for the regulation of our physiology, including hormonal and metabolic homeostasis. Here we will review the structure, organisation and molecular machinery that make our circadian clock work, and its relevance for the proper functioning of physiological processes. We will also describe the interconnections between circadian rhythms and endocrine homeostasis, as well as the underlying consequences that circadian dysregulations might have in the development of several pathologic affections...
February 4, 2017: Biology
https://www.readbyqxmd.com/read/28164449/role-of-sleep-and-circadian-disruption-on-energy-expenditure-and-in-metabolic-predisposition-to-human-obesity-and-metabolic-disease
#6
REVIEW
A W McHill, K P Wright
Weight gain, obesity and diabetes have reached alarming levels in the developed world. Traditional risk factors such as over-eating, poor nutritional choices and lack of exercise cannot fully account for the high prevalence of metabolic disease. This review paper examines the scientific evidence on two novel risk factors that contribute to dys-regulated metabolic physiology: sleep disruption and circadian misalignment. Specifically, fundamental relationships between energy metabolism and sleep and circadian rhythms and the impact of sleep and circadian disruption on metabolic physiology are examined...
February 2017: Obesity Reviews: An Official Journal of the International Association for the Study of Obesity
https://www.readbyqxmd.com/read/28162893/circadian-entrainment-to-the-natural-light-dark-cycle-across-seasons-and-the-weekend
#7
Ellen R Stothard, Andrew W McHill, Christopher M Depner, Brian R Birks, Thomas M Moehlman, Hannah K Ritchie, Jacob R Guzzetti, Evan D Chinoy, Monique K LeBourgeois, John Axelsson, Kenneth P Wright
Reduced exposure to daytime sunlight and increased exposure to electrical lighting at night leads to late circadian and sleep timing [1-3]. We have previously shown that exposure to a natural summer 14 hr 40 min:9 hr 20 min light-dark cycle entrains the human circadian clock to solar time, such that the internal biological night begins near sunset and ends near sunrise [1]. Here we show that the beginning of the biological night and sleep occur earlier after a week's exposure to a natural winter 9 hr 20 min:14 hr 40 min light-dark cycle as compared to the modern electrical lighting environment...
February 2, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28158242/de-novo-characterization-of-micrornas-in-oriental-fruit-moth-grapholita-molesta-and-selection-of-reference-genes-for-normalization-of-microrna-expression
#8
Xiu Wang, Yisong Li, Jing Zhang, Qingwen Zhang, Xiaoxia Liu, Zhen Li
MicroRNAs (miRNAs) are a group of endogenous non-coding small RNAs that have critical regulatory functions in almost all known biological processes at the post-transcriptional level in a variety of organisms. The oriental fruit moth Grapholita molesta is one of the most serious pests in orchards worldwide and threatens the production of Rosacea fruits. In this study, a de novo small RNA library constructed from mixed stages of G. molesta was sequenced through Illumina sequencing platform and a total of 536 mature miRNAs consisting of 291 conserved and 245 novel miRNAs were identified...
2017: PloS One
https://www.readbyqxmd.com/read/28156168/evolution-of-circadian-rhythms-in-drosophila-melanogaster-populations-reared-in-constant-light-and-dark-regimes-for-over-330-generations
#9
Radhika Shindey, Vishwanath Varma, K L Nikhil, Vijay Kumar Sharma
Organisms are believed to have evolved circadian clocks as adaptations to deal with cyclic environmental changes, and therefore it has been hypothesized that evolution in constant environments would lead to regression of such clocks. However, previous studies have yielded mixed results, and evolution of circadian clocks under constant conditions has remained an unsettled topic of debate in circadian biology. In continuation of our previous studies, which reported persistence of circadian rhythms in Drosophila melanogaster populations evolving under constant light, here we intended to examine whether circadian clocks and the associated properties evolve differently under constant light and constant darkness...
February 3, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28154741/social-modulation-of-the-daily-activity-rhythm-in-a-solitary-subterranean-rodent-the-tuco-tuco-ctenomys-sp
#10
Barbara Mizumo Tomotani, Juan Pablo Amaya, Gisele Akemi Oda, Veronica Sandra Valentinuzzi
South American subterranean rodents are mainly described as solitary and mutual synchronization was never observed among individuals maintained together in laboratory. We report that a single birth event was capable of disrupting the robust nocturnal activity rhythm of singly housed tuco-tucos from north-west Argentina. "Around-the-clock activity" was displayed by 8 out of 13 animals whose cages were closer to the newborn pups. However, experimental exposure to a pup vocalization did not produce a similar effect on the rhythms of adult animals...
October 2016: Sleep Science
https://www.readbyqxmd.com/read/28145903/the-aging-clock-circadian-rhythms-and-later-life
#11
REVIEW
Suzanne Hood, Shimon Amir
Circadian rhythms play an influential role in nearly all aspects of physiology and behavior in the vast majority of species on Earth. The biological clockwork that regulates these rhythms is dynamic over the lifespan: rhythmic activities such as sleep/wake patterns change markedly as we age, and in many cases they become increasingly fragmented. Given that prolonged disruptions of normal rhythms are highly detrimental to health, deeper knowledge of how our biological clocks change with age may create valuable opportunities to improve health and longevity for an aging global population...
February 1, 2017: Journal of Clinical Investigation
https://www.readbyqxmd.com/read/28141890/transcriptome-dynamics-over-a-lunar-month-in-a-broadcast-spawning-acroporid-coral
#12
Matthew J Oldach, Matthew Workentine, Mikhail V Matz, T-Y Fan, Peter D Vize
On one night per year, at a specific point in the lunar cycle, one of the most extraordinary reproductive events on the planet unfolds as hundreds of millions of broadcast spawning corals release their trillions of gametes into the waters of the tropical seas. Each species spawns on a specific night within the lunar cycle, typically from full moon to third quarter moon, and in a specific time window after sunset. This accuracy is essential to achieve efficient fertilization in the vastness of the oceans. In this report we use transcriptome sequencing at noon and midnight across an entire lunar cycle to explore how Acroporid corals interpret lunar signals...
January 31, 2017: Molecular Ecology
https://www.readbyqxmd.com/read/28140399/timing-of-light-exposure-affects-mood-and-brain-circuits
#13
REVIEW
T A Bedrosian, R J Nelson
Temporal organization of physiology is critical for human health. In the past, humans experienced predictable periods of daily light and dark driven by the solar day, which allowed for entrainment of intrinsic circadian rhythms to the environmental light-dark cycles. Since the adoption of electric light, however, pervasive exposure to nighttime lighting has blurred the boundaries of day and night, making it more difficult to synchronize biological processes. Many systems are under circadian control, including sleep-wake behavior, hormone secretion, cellular function and gene expression...
January 31, 2017: Translational Psychiatry
https://www.readbyqxmd.com/read/28139730/joint-genome-wide-association-and-transcriptome-sequencing-reveals-a-complex-polygenic-network-underlying-hypocotyl-elongation-in-rapeseed-brassica-napus-l
#14
Xiang Luo, Zhifei Xue, Chaozhi Ma, Kaining Hu, Ziru Zeng, Shengwei Dou, Jinxing Tu, Jinxiong Shen, Bin Yi, Tingdong Fu
Hypocotyl elongation is considered an important typical seedling trait contributing directly to an increase in and stabilization of the yield in Brassica napus, but its molecular genetic mechanism is poorly understood. In the present study, hypocotyl lengths of 210 lines were measured in an illuminated culture room. A genome-wide association study (GWAS) was performed with 23,435 single nucleotide polymorphisms (SNPs) for hypocotyl length. Three lines with long hypocotyl length and three lines with short hypocotyl length from one doubled haploid line (DH) population were used for transcriptome sequencing...
January 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28113403/a-biochemical-oscillator-using-excitatory-molecules-for-nanonetworks
#15
Ethungshan Shitiri, Ho-Shin Cho
For nanonetworks to be able to achieve large-scale functionality, such as to respond collectively to a trigger, synchrony between nanomachines is essential. However, to facilitate synchronization, some sort of physical clocking mechanism is required, such as the oscillators driven by auto-inhibitory molecules or by auto-inducing molecules. In this study, taking inspiration from the widely studied biological oscillatory phenomena called Calcium (Ca2+) oscillations, we undertake a different approach to design an oscillator...
October 18, 2016: IEEE Transactions on Nanobioscience
https://www.readbyqxmd.com/read/28108951/physiological-links-of-circadian-clock-and-biological-clock-of-aging
#16
REVIEW
Fang Liu, Hung-Chun Chang
Circadian rhythms orchestrate biochemical and physiological processes in living organisms to respond the day/night cycle. In mammals, nearly all cells hold self-sustained circadian clocks meanwhile couple the intrinsic rhythms to systemic changes in a hierarchical manner. The suprachiasmatic nucleus (SCN) of the hypothalamus functions as the master pacemaker to initiate daily synchronization according to the photoperiod, in turn determines the phase of peripheral cellular clocks through a variety of signaling relays, including endocrine rhythms and metabolic cycles...
January 20, 2017: Protein & Cell
https://www.readbyqxmd.com/read/28106159/temporal-variations-in-presynaptic-release-probability-in-the-lateral-habenula
#17
Hoyong Park, Myunghyun Cheon, Sungmin Kim, ChiHye Chung
Rhythmicity plays an important role in a number of biological systems. The habenular complex is reported to contain an intrinsic molecular clock and to show rhythmic expression of circadian clock genes and proteins including per2/PER2. In this study, we observed that there is a temporal rhythmicity in the presynaptic efficacy of the lateral habenula (LHb) neurons. We collected a substantial number of recordings at different time points of the day during the light phase. The frequency and amplitude of spontaneous excitatory transmission were increased in the afternoon compared to recordings performed in the morning...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28101270/using-online-active-learning-techniques-to-convey-time-compensated-sun-compass-orientation-in-the-eastern-north-american-monarch
#18
Noah H Green, Douglas G McMahon, Cynthia Brame
A common tool that animals use to navigate in a constant direction is known as "time compensated sun compass orientation." This is a process by which animals use the position of the sun along with information from their internal circadian clocks to determine and maintain a directional heading. Many circadian scientists and educators use this process as an example of how the internal circadian clock can directly influence animal behavior. However, many students have difficulty grasping this biological process due to its multivariable nature...
December 2016: Journal of Microbiology & Biology Education: JMBE
https://www.readbyqxmd.com/read/28087932/the-complexity-of-fungal-vision
#19
Reinhard Fischer, Jesus Aguirre, Alfredo Herrera-Estrella, Luis M Corrochano
Life, as we know it, would not be possible without light. Light is not only a primary source of energy, but also an important source of information for many organisms. To sense light, only a few photoreceptor systems have developed during evolution. They are all based on an organic molecule with conjugated double bonds that allows energy transfer from visible (or UV) light to its cognate protein to translate the primary physical photoresponse to cell-biological actions. The three main classes of receptors are flavin-based blue-light, retinal-based green-light (such as rhodopsin), and linear tetrapyrrole-based red-light sensors...
December 2016: Microbiology Spectrum
https://www.readbyqxmd.com/read/28072861/identification-of-the-molecular-clockwork-of-the-oyster-crassostrea-gigas
#20
Mickael Perrigault, Damien Tran
Molecular clock system constitutes the origin of biological rhythms that allow organisms to anticipate cyclic environmental changes and adapt their behavior and physiology. Components of the molecular clock are largely conserved across a broad range of species but appreciable diversity in clock structure and function is also present especially in invertebrates. The present work aimed at identify and characterize molecular clockwork components in relationship with the monitoring of valve activity behavior in the oyster Crassostrea gigas...
2017: PloS One
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