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https://www.readbyqxmd.com/read/29187422/dependency-of-heterochromatin-domains-on-replication-factors
#1
Leonie Johanna Jahn, Bethany Mason, Peter Brøgger, Tea Toteva, Dennis Kim Nielsen, Genevieve Thon
Chromatin structure regulates both genome expression and dynamics in eukaryotes where large heterochromatic regions are epigenetically silenced through the methylation of histone H3K9, histone deacetylation, and assembly of repressive complexes. Previous genetic screens with the fission yeast Schizosaccharomyces pombe have led to the identification of key enzymatic activities and structural constituents of heterochromatin. We report here on additional factors discovered by screening a library of deletion mutants for silencing defects at the edge of a heterochromatic domain bound by its natural boundary - the IR-R+ element - or by ectopic boundaries...
November 29, 2017: G3: Genes—Genomes—Genetics
https://www.readbyqxmd.com/read/29183263/inverse-european-latitudinal-cline-at-the-timeless-locus-of-drosophila-melanogaster-reveals-selection-on-a-clock-gene-population-genetics-of-ls-tim
#2
Valeria Zonato, Stefano Vanin, Rodolfo Costa, Eran Tauber, Charalambos P Kyriacou
The spread of adaptive genetic variants in populations is a cornerstone of evolutionary theory but with relatively few biologically well-understood examples. Previous work on the ls-tim variant of timeless, which encodes the light-sensitive circadian regulator in Drosophila melanogaster, suggests that it may have originated in southeastern Italy. Flies characterized by the new allele show photoperiod-related phenotypes likely to be adaptive in seasonal environments. ls-tim may be spreading from its point of origin in Italy by directional selection, but there are alternative explanations for its observed clinal geographical distribution, including balancing selection and demography...
November 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/29169033/mapping-complex-mind-states-eeg-neural-substrates-of-meditative-unified-compassionate-awareness
#3
Poppy L A Schoenberg, Andrea Ruf, John Churchill, Daniel P Brown, Judson A Brewer
Specific mental training cultivates diminished self-reference, encompassing non-duality, emptiness, awakened-awareness, and compassionate experiences. We aimed to elucidate the neural substrates of four distinct, interdependent Essence-of-Mind states: (1) timelessness, (2) non-preference, non-duality, non-conceptualization, (3) the view of luminosity and limitlessness, (4) unified compassionate experience of oneness (stable awakened-awareness). EEG data were collected from 30 advanced meditators concomitant to eyes-open/eyes-closed resting baseline, followed by 60-min of instructed practice...
November 20, 2017: Consciousness and Cognition
https://www.readbyqxmd.com/read/29123070/redox-sensitive-alteration-of-replisome-architecture-safeguards-genome-integrity
#4
Kumar Somyajit, Rajat Gupta, Hana Sedlackova, Kai John Neelsen, Fena Ochs, Maj-Britt Rask, Chunaram Choudhary, Jiri Lukas
DNA replication requires coordination between replication fork progression and deoxynucleotide triphosphate (dNTP)-generating metabolic pathways. We find that perturbation of ribonucleotide reductase (RNR) in humans elevates reactive oxygen species (ROS) that are detected by peroxiredoxin 2 (PRDX2). In the oligomeric state, PRDX2 forms a replisome-associated ROS sensor, which binds the fork accelerator TIMELESS when exposed to low levels of ROS. Elevated ROS levels generated by RNR attenuation disrupt oligomerized PRDX2 to smaller subunits, whose dissociation from chromatin enforces the displacement of TIMELESS from the replisome...
November 10, 2017: Science
https://www.readbyqxmd.com/read/29103936/vrille-controls-pdf-neuropeptide-accumulation-and-arborization-rhythms-in-small-ventrolateral-neurons-to-drive-rhythmic-behavior-in-drosophila
#5
Kushan L Gunawardhana, Paul E Hardin
In Drosophila, the circadian clock is comprised of transcriptional feedback loops that control rhythmic gene expression responsible for daily rhythms in physiology, metabolism, and behavior. The core feedback loop, which employs CLOCK-CYCLE (CLK-CYC) activators and PERIOD-TIMELESS (PER-TIM) repressors to drive rhythmic transcription peaking at dusk, is required for circadian timekeeping and overt behavioral rhythms. CLK-CYC also activates an interlocked feedback loop, which uses the PAR DOMAIN PROTEIN 1ε (PDP1ε) activator and the VRILLE (VRI) repressor to drive rhythmic transcription peaking at dawn...
November 20, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28990443/mapping-quantitative-trait-loci-underlying-circadian-light-sensitivity-in-drosophila
#6
Adeolu B Adewoye, Sergey V Nuzhdin, Eran Tauber
Despite the significant advance in our understanding of the molecular basis of light entrainment of the circadian clock in Drosophila, the underlying genetic architecture is still largely unknown. The aim of this study was to identify loci associated with variation in circadian photosensitivity, which are important for the evolution of this trait. We have used complementary approaches that combined quantitative trait loci (QTL) mapping, complementation testing, and transcriptome profiling to dissect this variation...
October 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28984839/complete-mitochondrial-genome-sequencing-of-a-burial-from-a-romano-christian-cemetery-in-the-dakhleh-oasis-egypt-preliminary-indications
#7
J Eldon Molto, Odile Loreille, Elizabeth K Mallott, Ripan S Malhi, Spence Fast, Jennifer Daniels-Higginbotham, Charla Marshall, Ryan Parr
The curse of ancient Egyptian DNA was lifted by a recent study which sequenced the mitochondrial genomes (mtGenome) of 90 ancient Egyptians from the archaeological site of Abusir el-Meleq. Surprisingly, these ancient inhabitants were more closely related to those from the Near East than to contemporary Egyptians. It has been accepted that the timeless highway of the Nile River seeded Egypt with African genetic influence, well before pre-Dynastic times. Here we report on the successful recovery and analysis of the complete mtGenome from a burial recovered from a remote Romano-Christian cemetery, Kellis 2 (K2)...
October 6, 2017: Genes
https://www.readbyqxmd.com/read/28973907/clock-stabilizes-cycle-to-initiate-clock-function-in-drosophila
#8
Tianxin Liu, Guruswamy Mahesh, Wangjie Yu, Paul E Hardin
The Drosophila circadian clock keeps time via transcriptional feedback loops. These feedback loops are initiated by CLOCK-CYCLE (CLK-CYC) heterodimers, which activate transcription of genes encoding the feedback repressors PERIOD and TIMELESS. Circadian clocks normally operate in ∼150 brain pacemaker neurons and in many peripheral tissues in the head and body, but can also be induced by expressing CLK in nonclock cells. These ectopic clocks also require cyc, yet CYC expression is restricted to canonical clock cells despite evidence that cyc mRNA is widely expressed...
October 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28964713/circadian-signaling-in-the-northern-krill-meganyctiphanes-norvegica-in-silico-prediction-of-the-protein-components-of-a-putative-clock-system-using-a-publicly-accessible-transcriptome
#9
Andrew E Christie, Andy Yu, Micah G Pascual
The Northern krill Meganyctiphanes norvegica is a significant component of the zooplankton community in many regions of the North Atlantic Ocean. In the areas it inhabits, M. norvegica is of great importance ecologically, as it is both a major consumer of phytoplankton/small zooplankton and is a primary food source for higher-level consumers. One behavior of significance for both feeding and predator avoidance in Meganyctiphanes is diel vertical migration (DVM), i.e., a rising from depth at dusk and a return to depth at dawn...
September 28, 2017: Marine Genomics
https://www.readbyqxmd.com/read/28940754/daily-expression-of-two-circadian-clock-genes-in-compound-eye-of-helicoverpa-armigera-evidence-for-peripheral-tissue-circadian-timing
#10
Shuo Yan, Yan-Jun Liu, Jia-Lin Zhu, Wei-Na Cui, Xin-Fang Zhang, Yu-Hui Yang, Xiao-Ming Liu, Qing-Wen Zhang, Xiao-Xia Liu
Circadian clock genes in peripheral tissues usually play an important role in regulating the circadian rhythms. Light is the most important environmental signal for synchronizing endogenous rhythms with the daily light-dark cycle, and compound eyes are known as the principal circadian photoreceptor for photic entrainment in most moths. However, there is little evidence for circadian timing in the compound eyes. In the current study, we isolated the timeless gene, designated Ha-tim (GenBank accession number: KM233162), from the cotton bollworm Helicoverpa armigera...
September 23, 2017: Insect Science
https://www.readbyqxmd.com/read/28893860/coordination-between-differentially-regulated-circadian-clocks-generates-rhythmic-behavior
#11
Deniz Top, Michael W Young
Specialized groups of neurons in the brain are key mediators of circadian rhythms, receiving daily environmental cues and communicating those signals to other tissues in the organism for entrainment and to organize circadian physiology. In Drosophila, the "circadian clock" is housed in seven neuronal clusters, which are defined by their expression of the main circadian proteins, Period, Timeless, Clock, and Cycle. These clusters are distributed across the fly brain and are thereby subject to the respective environments associated with their anatomical locations...
September 11, 2017: Cold Spring Harbor Perspectives in Biology
https://www.readbyqxmd.com/read/28877799/remembering-dr-henry-w-gray-1827-1861-and-his-timeless-contribution-to-modern-medical-education
#12
Niti Shahi, Abigail L Brooks, Charles J Yeo, Scott W Cowan, Gerald A Isenberg
No abstract text is available yet for this article.
November 1, 2016: American Surgeon
https://www.readbyqxmd.com/read/28872696/the-light-cycle-controls-the-hatching-rhythm-in-bombyx-mori-via-negative-feedback-loop-of-the-circadian-oscillator
#13
Hui Tao, Xue Li, Jian-Feng Qiu, Heng-Jiang Liu, Da-Yan Zhang, Feng Chu, Yanghu Sima, Shi-Qing Xu
Hatching behavior is a key target in silkworm (Bombyx mori) rearing, especially for the control of Lepidoptera pests. According to previous research, hatching rhythms appear to be controlled by a clock mechanism that restricts or "gates" hatching to a particular time. However, the underlying mechanism remains elusive. Under 12-h light:12-h dark photoperiod (LD) conditions, the transcriptional levels of the chitinase5 (Cht5) and hatching enzyme-like (Hel) genes, as well as the enzymatic activities of their gene products, oscillated in time with ambient light cycles, as did the transcriptional levels of the cryptochrome 1, cryptochrome 2, period (per), and timeless genes, which are key components of the negative feedback loop of the circadian rhythm...
October 2017: Archives of Insect Biochemistry and Physiology
https://www.readbyqxmd.com/read/28781048/drosophila-cry-entrains-clocks-in-body-tissues-to-light-and-maintains-passive-membrane-properties-in-a-non-clock-body-tissue-independent-of-light
#14
Parul Agrawal, Jerry H Houl, Kushan L Gunawardhana, Tianxin Liu, Jian Zhou, Mark J Zoran, Paul E Hardin
Circadian (∼24 hr) clocks regulate daily rhythms in physiology, metabolism, and behavior via cell-autonomous transcriptional feedback loops. In Drosophila, the blue-light photoreceptor CRYPTOCHROME (CRY) synchronizes these feedback loops to light:dark cycles by binding to and degrading TIMELESS (TIM) protein. CRY also acts independently of TIM in Drosophila to alter potassium channel conductance in arousal neurons after light exposure, and in many animals CRY acts independently of light to repress rhythmic transcription...
August 21, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28760773/alternative-lengthening-of-telomeres-mediated-by-mitotic-dna-synthesis-engages-break-induced-replication-processes
#15
Jaewon Min, Woodring E Wright, Jerry W Shay
Alternative lengthening of telomeres (ALT) is a telomerase-independent telomere maintenance mechanism that occurs in a subset of cancers. By analyzing telomerase-positive cells and their human TERC knockout-derived ALT human cell lines, we show that ALT cells harbor more fragile telomeres representing telomere replication problems. ALT-associated replication defects trigger mitotic DNA synthesis (MiDAS) at telomeres in a RAD52-dependent, but RAD51-independent, manner. Telomeric MiDAS is a conservative DNA synthesis process, potentially mediated by break-induced replication, similar to type II ALT survivors in Saccharomyces cerevisiae Replication stresses induced by ectopic oncogenic expression of cyclin E, G-quadruplexes, or R-loop formation facilitate the ALT pathway and lead to telomere clustering, a hallmark of ALT cancers...
October 15, 2017: Molecular and Cellular Biology
https://www.readbyqxmd.com/read/28729216/self-assembled-aunps-for-ingrain-pigmentation-of-silk-fabrics-with-antibacterial-potency
#16
Hanan B Ahmed, Nancy S El-Hawary, Hossam E Emam
Nanogold was self-assembled for ingrain pigmentation of silk fabric with antibacterial properties. The functional groups of silk macromolecular polymeric chains were exploited for generation and stabilization of nanogold. Hydrogen peroxide was used for activation of silk molecular chains through increasing their reactivity and accessibility to be functionalized as manufacturer of nanogold without using any external agents. Effect of procedure sequencing was studied through addition of peroxide firstly (group A) and with Au salt (group B)...
December 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28712565/circadian-clock-involvement-in-zooplankton-diel-vertical-migration
#17
N Sören Häfker, Bettina Meyer, Kim S Last, David W Pond, Lukas Hüppe, Mathias Teschke
Biological clocks are a ubiquitous ancient and adaptive mechanism enabling organisms to anticipate environmental cycles and to regulate behavioral and physiological processes accordingly [1]. Although terrestrial circadian clocks are well understood, knowledge of clocks in marine organisms is still very limited [2-5]. This is particularly true for abundant species displaying large-scale rhythms like diel vertical migration (DVM) that contribute significantly to shaping their respective ecosystems [6]. Here we describe exogenous cycles and endogenous rhythms associated with DVM of the ecologically important and highly abundant planktic copepod Calanus finmarchicus...
July 24, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28636007/analysis-of-association-of-gene-variants-with-obesity-traits-in-new-zealand-european-children-at-6-years-of-age
#18
Mohanraj Krishnan, John M D Thompson, Edwin A Mitchell, Rinki Murphy, Lesley M E McCowan, Andrew N Shelling, G On Behalf Of The Children Of Scope Study Group
Childhood obesity is a public health problem, which is associated with a long-term increased risk of cardiovascular disease and premature mortality. Several gene variants have previously been identified that have provided novel insights into biological factors that contribute to the development of obesity. As obesity tracks through childhood into adulthood, identification of the genetic factors for obesity in early life is important. The objective of this study was to identify putative associations between genetic variants and obesity traits in children at 6 years of age...
July 25, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28633991/the-path-to-timelessness-insight-assignment-conditions-and-strong-anticipation
#19
REVIEW
Susie Vrobel
This paper focusses on the notions of time and timelessness in Eastern and Western thought traditions. The Introduction addresses the Eastern differentiation between the mind, which does not operate in a successive manner and is therefore not caught in time, and the time-laden successively operating mind and brain. I also describe how Jiddu Krishnamurti reconciles the two through insight, an event which restructures the brain and culminates in an eternal Now. In the following sections, I draw analogies to Western notions of timelessness and insight...
June 17, 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/28620087/daily-activity-of-the-housefly-musca-domestica-is-influenced-by-temperature-independent-of-3-utr-period-gene-splicing
#20
Olga Bazalova, David Dolezel
Circadian clocks orchestrate daily activity patterns and free running periods of locomotor activity under constant conditions. While the first often depends on temperature, the latter is temperature-compensated over a physiologically relevant range. Here, we explored the locomotor activity of the temperate housefly Musca domestica Under low temperatures, activity was centered round a major and broad afternoon peak, while high temperatures resulted in activity throughout the photophase with a mild midday depression, which was especially pronounced in males exposed to long photoperiods...
August 7, 2017: G3: Genes—Genomes—Genetics
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