scholarly journals Functional Development of the Circadian Clock in the Zebrafish Pineal Gland

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Zohar Ben-Moshe ◽  
Nicholas S. Foulkes ◽  
Yoav Gothilf
Keyword(s):  
Pineal Gland ◽  
Circadian Clock ◽  
Rapid Development ◽  
Model Organism ◽  
Circadian System ◽  
Zebrafish Model ◽  
Peripheral Oscillators ◽  
Clock Gene Expression ◽  
Functional Development ◽  
Central Clock

The zebrafish constitutes a powerful model organism with unique advantages for investigating the vertebrate circadian timing system and its regulation by light. In particular, the remarkably early and rapid development of the zebrafish circadian system has facilitated exploring the factors that control the onset of circadian clock function during embryogenesis. Here, we review our understanding of the molecular basis underlying functional development of the central clock in the zebrafish pineal gland. Furthermore, we examine how the directly light-entrainable clocks in zebrafish cell lines have facilitated unravelling the general mechanisms underlying light-induced clock gene expression. Finally, we summarize how analysis of the light-induced transcriptome and miRNome of the zebrafish pineal gland has provided insight into the regulation of the circadian system by light, including the involvement of microRNAs in shaping the kinetics of light- and clock-regulated mRNA expression. The relative contributions of the pineal gland central clock and the distributed peripheral oscillators to the synchronization of circadian rhythms at the whole animal level are a crucial question that still remains to be elucidated in the zebrafish model.

The Circadian Clock of the Unicellular Eukaryotic Model Organism Chlamydomonas reinhardtii

2003 ◽  
Vol 384 (5) ◽  
pp. 689-695 ◽  
Author(s):  
M. Mittag ◽  
V. Wagner
Keyword(s):  
Circadian Clock ◽  
Chlamydomonas Reinhardtii ◽  
Rna Binding ◽  
Outer Space ◽  
Expression Patterns ◽  
Model Organism ◽  
Nuclear Genome ◽  
Circadian System ◽  
Transcriptional Level ◽  
Circadian Expression

Abstract The green unicellular alga Chlamydomonas reinhardtii, also called 'green yeast', emerged in the past years as a model organism for specific scientific questions such as chloroplast biogenesis and function, the composition of the flagella including its basal apparatus, or the mechanism of the circadian clock. Sequencing of its chloroplast and mitochondrial genomes have already been completed and a first draft of its nuclear genome has also been released recently. In C. reinhardtii several circadian rhythms are physiologically well characterized, and one of them has even been shown to operate in outer space. Circadian expression patterns of nuclear and plastid genes have been studied. The mode of regulation of these genes occurs at the transcriptional level, although there is also evidence for posttranscriptional control. A clock-controlled, phylogenetically conserved RNA-binding protein was characterized in this alga, which interacts with several mRNAs that all contain a common cis-acting motif. Its function within the circadian system is currently under investigation. This review summarizes the current state of the knowledge about the circadian system in C. reinhardtii and points out its potential for future studies.

scholarly journals Circadian Clock Genes and Photoperiodism: Comprehensive Analysis of Clock Gene Expression in the Mediobasal Hypothalamus, the Suprachiasmatic Nucleus, and the Pineal Gland of Japanese Quail under Various Light Schedules

Endocrinology ◽  
2003 ◽  
Vol 144 (9) ◽  
pp. 3742-3748 ◽  
Author(s):  
Shinobu Yasuo ◽  
Miwa Watanabe ◽  
Naritoshi Okabayashi ◽  
Shizufumi Ebihara ◽  
Takashi Yoshimura
Keyword(s):  
Pineal Gland ◽  
Circadian Clock ◽  
Suprachiasmatic Nucleus ◽  
Clock Genes ◽  
Expression Patterns ◽  
Hypothalamic Nucleus ◽  
Mediobasal Hypothalamus ◽  
Clock Gene Expression ◽  
Circadian Clock Genes ◽  
Important Center

Abstract In birds, the mediobasal hypothalamus (MBH) including the infundibular nucleus, inferior hypothalamic nucleus, and median eminence is considered to be an important center that controls the photoperiodic time measurement. Here we show expression patterns of circadian clock genes in the MBH, putative suprachiasmatic nucleus (SCN), and pineal gland, which constitute the circadian pacemaker under various light schedules. Although expression patterns of clock genes were different between long and short photoperiod in the SCN and pineal gland, the results were not consistent with those under night interruption schedule, which causes testicular growth. These results indicate that different expression patterns of the circadian clock genes in the SCN and pineal gland are not an absolute requirement for encoding and decoding of seasonal information. In contrast, expression patterns of clock genes in the MBH were stable under various light conditions, which enables animals to keep a steady-state photoinducible phase.

scholarly journals The circadian clock uses different environmental time cues to synchronize emergence and locomotion of the solitary bee Osmia bicornis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Katharina Beer ◽  
Mariela Schenk ◽  
Charlotte Helfrich-Förster ◽  
Andrea Holzschuh
Keyword(s):  
Circadian Clock ◽  
Circadian System ◽  
Evolutionary Adaptation ◽  
Solitary Bee ◽  
Daily Rhythms ◽  
Osmia Bicornis ◽  
Cavity Nesting ◽  
Impact On Survival ◽  
Life On Earth ◽  
And Behavior

AbstractLife on earth adapted to the daily reoccurring changes in environment by evolving an endogenous circadian clock. Although the circadian clock has a crucial impact on survival and behavior of solitary bees, many aspects of solitary bee clock mechanisms remain unknown. Our study is the first to show that the circadian clock governs emergence in Osmia bicornis, a bee species which overwinters as adult inside its cocoon. Therefore, its eclosion from the pupal case is separated by an interjacent diapause from its emergence in spring. We show that this bee species synchronizes its emergence to the morning. The daily rhythms of emergence are triggered by temperature cycles but not by light cycles. In contrast to this, the bee’s daily rhythms in locomotion are synchronized by light cycles. Thus, we show that the circadian clock of O. bicornis is set by either temperature or light, depending on what activity is timed. Light is a valuable cue for setting the circadian clock when bees have left the nest. However, for pre-emerged bees, temperature is the most important cue, which may represent an evolutionary adaptation of the circadian system to the cavity-nesting life style of O. bicornis.

Daily rhythm and regulation of clock gene expression in the rat pineal gland

2004 ◽  
Vol 120 (2) ◽  
pp. 164-172 ◽  
Author(s):  
V Simonneaux ◽  
V.-J Poirel ◽  
M.-L Garidou ◽  
D Nguyen ◽  
E Diaz-Rodriguez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pineal Gland ◽  
Clock Gene ◽  
Daily Rhythm ◽  
Clock Gene Expression ◽  
Rat Pineal Gland

scholarly journals ZFIN, The zebrafish model organism database: Updates and new directions

genesis ◽  
2015 ◽  
Vol 53 (8) ◽  
pp. 498-509 ◽  
Author(s):  
Leyla Ruzicka ◽  
Yvonne M. Bradford ◽  
Ken Frazer ◽  
Douglas G. Howe ◽  
Holly Paddock ◽  
...  
Keyword(s):  
Model Organism ◽  
Model Organism Database ◽  
Zebrafish Model ◽  
Database Updates ◽  
New Directions

scholarly journals Mask R-CNN Based C. Elegans Detection with a DIY Microscope

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 257
Author(s):  
Sebastian Fudickar ◽  
Eike Jannik Nustede ◽  
Eike Dreyer ◽  
Julia Bornhorst
Keyword(s):  
Cell Biology ◽  
High Throughput Screening ◽  
Low Cost ◽  
Image Acquisition ◽  
Rapid Development ◽  
Model Organism ◽  
Large Data ◽  
Data Set ◽  
C Elegans ◽  
Do It Yourself

Caenorhabditis elegans (C. elegans) is an important model organism for studying molecular genetics, developmental biology, neuroscience, and cell biology. Advantages of the model organism include its rapid development and aging, easy cultivation, and genetic tractability. C. elegans has been proven to be a well-suited model to study toxicity with identified toxic compounds closely matching those observed in mammals. For phenotypic screening, especially the worm number and the locomotion are of central importance. Traditional methods such as human counting or analyzing high-resolution microscope images are time-consuming and rather low throughput. The article explores the feasibility of low-cost, low-resolution do-it-yourself microscopes for image acquisition and automated evaluation by deep learning methods to reduce cost and allow high-throughput screening strategies. An image acquisition system is proposed within these constraints and used to create a large data-set of whole Petri dishes containing C. elegans. By utilizing the object detection framework Mask R-CNN, the nematodes are located, classified, and their contours predicted. The system has a precision of 0.96 and a recall of 0.956, resulting in an F1-Score of 0.958. Considering only correctly located C. elegans with an [email protected] IoU, the system achieved an average precision of 0.902 and a corresponding F1 Score of 0.906.

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