scholarly journals Light-induced asymmetries in the embryonic retina are mediated by the vascular system and extracellular matrix

2021 ◽  
Author(s):  
Elisabetta Versace ◽  
Paola Sgado ◽  
Julia George ◽  
Jasmine Loveland ◽  
Joseph Ward ◽  
...  
Keyword(s):  
Gene Expression ◽  
Extracellular Matrix ◽  
Gene Networks ◽  
Time Course ◽  
Vascular System ◽  
Time Window ◽  
Light Exposure ◽  
Sensitive Period ◽  
Iodothyronine Deiodinase ◽  
The Right

Left-right asymmetries in the nervous system (lateralisation) influence a broad range of behaviours, from social responses to navigation and language. The role and pathways of endogenous and environmental mechanisms in the ontogeny of lateralisation remains to be established. The domestic chick is a model of both endogenous and experience-induced lateralisation driven by light exposure. Following the endogenous rightward rotation of the embryo, the asymmetrical position in the egg results in a greater exposure of the right eye to environmental light. To identify the genetic pathways activated by asymmetric light stimulation, and their time course, we exposed embryos to different light regimes: darkness, 6 hours of light and 24 hours of light. We used RNA-seq to compare gene expression in the right and left retinas and telencephalon. As expected, no differential expression between left and right was present in darkness. We detected differential gene expression in right vs left retina after 6 hours of light exposure. This difference disappeared before 24 hours of light exposure, suggesting that light-induced activation is a self-terminating phenomenon. This transient effect of light exposure was associated with a downregulation of the sensitive-period mediator gene DIO2 (iodothyronine deiodinase 2) in the right retina. No differences between genes expressed in the right vs. left telencephalon were detected. Gene networks associated with lateralisation were connected to vascularisation, cell motility, and the extracellular matrix. Interestingly, we know that the extracellular matrix - including the differentially expressed PDGFRB (platelet-derived growth factor receptor β) gene - is involved in both sensitive periods and in the endogenous chiral mechanism of primary cilia, that drives lateralisation. Our data show a similarity between endogenous and experience-driven lateralisation, identifying functional gene networks that affect lateralisation in a specific time window.

Interhemispheric EEG asymmetries during unilateral bright-light exposure and subsequent sleep in humans

2008 ◽  
Vol 294 (3) ◽  
pp. R1053-R1060 ◽  
Author(s):  
Christian Cajochen ◽  
Rosalba Di Biase ◽  
Makoto Imai
Keyword(s):  
Visual Cortex ◽  
Time Course ◽  
Visual Stimulation ◽  
Light Exposure ◽  
Bright Light ◽  
Occipital Cortex ◽  
Alpha Activity ◽  
Hemispheric Dominance ◽  
Eeg Activity ◽  
The Right

We tested whether evening exposure to unilateral photic stimulation has repercussions on interhemispheric EEG asymmetries during wakefulness and later sleep. Because light exerts an alerting response in humans, which correlates with a decrease in waking EEG theta/alpha-activity and a reduction in sleep EEG delta activity, we hypothesized that EEG activity in these frequency bands show interhemispheric asymmetries after unilateral bright light (1,500 lux) exposure. A 2-h hemi-field light exposure acutely suppressed occipital EEG alpha activity in the ipsilateral hemisphere activated by light. Subjects felt more alert during bright light than dim light, an effect that was significantly more pronounced during activation of the right than the left visual cortex. During subsequent sleep, occipital EEG activity in the delta and theta range was significantly reduced after activation of the right visual cortex but not after stimulation of the left visual cortex. Furthermore, hemivisual field light exposure was able to shift the left predominance in occipital spindle EEG activity toward the stimulated hemisphere. Time course analysis revealed that this spindle shift remained significant during the first two sleep cycles. Our results reflect rather a hemispheric asymmetry in the alerting action of light than a use-dependent recovery function of sleep in response to the visual stimulation during prior waking. However, the observed shift in the spindle hemispheric dominance in the occipital cortex may still represent subtle local use-dependent recovery functions during sleep in a frequency range different from the delta range.

scholarly journals Gene expression profiling of trout muscle during flesh quality recovery following spawning

BMC Genomics ◽  
2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Yéléhi-Diane Ahongo ◽  
Aurélie Le Cam ◽  
Jérôme Montfort ◽  
Jérôme Bugeon ◽  
Florence Lefèvre ◽  
...  
Keyword(s):  
Gene Expression ◽  
Extracellular Matrix ◽  
Large Scale ◽  
Time Course ◽  
White Muscle ◽  
Flesh Quality ◽  
Fillet Quality ◽  
Genes Encoding ◽  
Post Spawning ◽  
Trout Muscle

Abstract Background Sexual maturation causes loss of fish muscle mass and deterioration of fillet quality attributes that prevent market success. We recently showed that fillet yield and flesh quality recover in female trout after spawning. To gain insight into the molecular mechanisms regulating flesh quality recovery, we used an Agilent-based microarray platform to conduct a large-scale time course analysis of gene expression in female trout white muscle from spawning to 33 weeks post-spawning. Results In sharp contrast to the situation at spawning, muscle transcriptome of female trout at 33 weeks after spawning was highly similar to that of female trout of the same cohort that did not spawn, which is consistent with the post-spawning flesh quality recovery. Large-scale time course analysis of gene expression in trout muscle during flesh quality recovery following spawning led to the identification of approximately 3340 unique differentially expressed genes that segregated into four major clusters with distinct temporal expression profiles and functional categories. The first cluster contained approximately 1350 genes with high expression at spawning and downregulation after spawning and was enriched with genes linked to mitochondrial ATP synthesis, fatty acid catabolism and proteolysis. A second cluster of approximately 540 genes with transient upregulation 2 to 8 weeks after spawning was enriched with genes involved in transcription, RNA processing, translation, ribosome biogenesis and protein folding. A third cluster containing approximately 300 genes upregulated 4 to 13 weeks after spawning was enriched with genes encoding ribosomal subunits or regulating protein folding. Finally, a fourth cluster that contained approximately 940 genes with upregulation 8 to 24 weeks after spawning, was dominated by genes encoding myofibrillar proteins and extracellular matrix components and genes involved in glycolysis. Conclusion Overall, our study indicates that white muscle tissue restoration and flesh quality recovery after spawning are associated with transcriptional changes promoting anaerobic ATP production, muscle fibre hypertrophic growth and extracellular matrix remodelling. The generation of the first database of genes associated with post-spawning muscle recovery may provide insights into the molecular and cellular mechanisms controlling muscle yield and fillet quality in fish and provide a useful list of potential genetic markers for these traits.

Time course of gene expression in rat experimental autoimmune myocarditis

2002 ◽  
Vol 103 (6) ◽  
pp. 623-632 ◽  
Author(s):  
Haruo HANAWA ◽  
Satoru ABE ◽  
Manabu HAYASHI ◽  
Tsuyoshi YOSHIDA ◽  
Kaori YOSHIDA ◽  
...  
Keyword(s):  
Gene Expression ◽  
Extracellular Matrix ◽  
Time Course ◽  
Collagen Type ◽  
Fold Increase ◽  
Cardiac Myosin ◽  
Autoimmune Myocarditis ◽  
Experimental Autoimmune Myocarditis ◽  
Experimental Autoimmune

Genetic responses that characterize experimental autoimmune myocarditis (EAM) have not yet been determined. To investigate gene expression in the myocardium of EAM, absolute copy numbers of 44 mRNA species [calcium-handling proteins, contractile proteins, natriuretic peptides (NPs), cytokines, chemokines, growth factors, renin–angiotensin–aldosterone (RAA) system, endothelins (ETs) and extracellular matrix] in synthesized cDNA from a fixed quantity of total heart RNA were assessed using real-time reverse-transcriptase PCR at days 0, 14, 21 and 28 after immunization. α-Cardiac myosin showed a 26.3-fold decrease and β-cardiac myosin a 3.75-fold increase at day 14. Atrial NP and brain NP increased 47.7- and 6.35-fold at days 21 and 14 respectively. Angiotensin II type 1 receptor, angiotensin-converting enzyme and ET1 increased 22.3-fold at day 21, 6.30-fold at day 21 and 16.8-fold at day 14 respectively. Aldosterone receptor decreased 2.15-fold at day 14, but aldosterone synthetase was detected only at days 14 and 21. Interleukin (IL)-2, IL-10, interferon-γ and monocyte chemo-attractant protein-1 increased 9.08-fold at day 14, 398-fold at day 21, 43.1-fold at day 14 and 142-fold at day 14 respectively. Collagen type 3, collagen type 1 and fibronectin increased 34.6-, 1.74- and 44.4-fold respectively at day 21. Interestingly, osteopontin showed a 4540-fold increase and it was the highest mRNA of all at day 14. An isoform of cardiac myosin and NP are dramatically changed in EAM. RAA system and ET expressions are changed differently during the EAM time course. Cytokine, chemokine and extracellular matrix greatly increase and, in particular, large numbers of osteopontin mRNA are expressed in early EAM.

scholarly journals Time-Course Transcriptome Study Reveals Mode of bZIP Transcription Factors on Light Exposure in Arabidopsis

2020 ◽  
Vol 21 (6) ◽  
pp. 1993 ◽  
Author(s):  
Yukio Kurihara ◽  
Yuko Makita ◽  
Haruka Shimohira ◽  
Minami Matsui
Keyword(s):  
Gene Expression ◽  
Time Course ◽  
Target Genes ◽  
Light Exposure ◽  
Expression Profiles ◽  
Red Light ◽  
Monochromatic Light ◽  
Regulation Of Gene Expression ◽  
Light Irradiation

The etiolation process, which occurs after germination, is terminated once light is perceived and then de-etiolation commences. During the de-etiolation period, monochromatic lights (blue, red and far-red) induce differences in gene expression profiles and plant behavior through their respective photoreceptors. ELONGATED HYPOCOTYL 5 (HY5), a bZIP-type transcription factor (TF), regulates gene expression in the de-etiolation process, and other bZIP TFs are also involved in this regulation. However, transcriptomic changes that occur in etiolated seedlings upon monochromatic light irradiation and the relationship with the bZIP TFs still remain to be elucidated. Here, we track changes in the transcriptome after exposure to white, blue, red and far-red light following darkness and reveal both shared and non-shared trends of transcriptomic change between the four kinds of light. Interestingly, after exposure to light, HY5 expression synchronized with those of the related bZIP TF genes, GBF2 and GBF3, rather than HY5 HOMOLOG (HYH). To speculate on the redundancy of target genes between the bZIP TFs, we inspected the genome-wide physical binding sites of homodimers of seven bZIP TFs, HY5, HYH, GBF1, GBF2, GBF3, GBF4 and EEL, using an in vitro binding assay. The results reveal large overlaps of target gene candidates, indicating a complicated regulatory literature among TFs. This work provides novel insight into understanding the regulation of gene expression of the plant response to monochromatic light irradiation.

Anatomical plasticity of synapses in the lamina of the optic lobe of the fly

1989 ◽  
Vol 323 (1214) ◽  
pp. 155-183 ◽  
Keyword(s):  
Time Course ◽  
Compound Eye ◽  
Light Exposure ◽  
Adult Life ◽  
Green Light ◽  
Developmental Time ◽  
Sensitive Period ◽  
Integrating Sphere ◽  
Synaptic Contacts ◽  
Frequency Changes

Insects are frequently assumed to have hard-wired nervous systems that fail to demonstrate functional plasticity. We have produced changes in synaptic frequency, and analysed their developmental time course, dynamics and reversibility, in the lamina underlying the compound eye of the fly, by exposing young adults to different visual stimuli. The class of synapse examined feeds back from L2, one of the monopolar cells found in each lamina cartridge, to photoreceptor terminals; each site is a synaptic dyad marked by the presence of a few, round vesicles surrounding a T - shaped presynaptic ribbon and, in the photoreceptor, by a subsynaptic vacuole. In control adult flies reared in normal room lighting, the frequency of synaptic profiles scored in micrographs of single sections initially increased until one day post-eclosion (E+l), but declined thereafter. Frequencies measured in left and right eyes of the same control animals were closely matched. Experimental flies were put for one to two days into an integrating sphere illuminated continuously with square-wave, 25 Hz green light. They had one eye occluded, so providing control comparisons between flicker-reared (FR) and occluded (dark-reared, DR ) eyes within the same animal. The DR eyes invariably ( n > 22) had higher frequencies of synaptic profiles than those seeing light, regardless of age or the period of light exposure, although the detailed relative effects of FR and DR depend upon the age of the animal. The evidence suggests that exposure to light actively depresses synaptic frequency and increases its variability. The greatest difference (30%) achieved was at two to four days after eclosion and there was no difference beyond six days, so demarcating a prospective sensitive period. Rearing in dc light was equally effective as FR so visual contrasts per se are apparently inessential. Frequency values can change rapidly. During the first 24 h post-eclosion, dr resulted in new synapses adding to L2’s complement of 25-35 at a maximum rate of 4 per 6 h, whereas light exposure caused a frequency decrease after as little as 6 h. Alternating 24 h periods of light and dark during the first two days produced reversible synaptic frequency changes. Individual synaptic contacts enlarge with age but not significantly with different visual experiences. The decrease in frequency of synaptic profiles with age thus actually underestimates the true decrease in synaptic number, whereas the altered synaptic frequencies seen after differential exposure represent true differences in synaptic number. The length of the axon of L2 is fixed, but its diameter increases, both with age and DR , although neither change generates the altered frequencies. Thus the L2 feedback synapse is plastic during the first four days of adult life, a conclusion validated by definitive counts of synaptic sites in short micrograph series. We cannot exclude, however, that the observed changes in the number of sampled synapses reflect individual synaptic contacts within a fixed population breaking and re-forming, so as to change their proximo-distal distribution.

scholarly journals Recursive regularization for inferring gene networks from time-course gene expression profiles

2009 ◽  
Vol 3 (1) ◽  
Author(s):  
Teppei Shimamura ◽  
Seiya Imoto ◽  
Rui Yamaguchi ◽  
André Fujita ◽  
Masao Nagasaki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Networks ◽  
Time Course ◽  
Expression Profiles ◽  
Gene Expression Profiles
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