timeless Dotaz Zobrazit nápovědu
Drosophila melanogaster has served as an excellent genetic model to decipher the molecular basis of the circadian clock. Two key proteins, PERIOD (PER) and TIMELESS (TIM), are particularly well explored and a number of various arrhythmic, slow, and fast clock mutants have been identified in classical genetic screens. Interestingly, the free running period (tau, τ) is influenced by temperature in some of these mutants, whereas τ is temperature-independent in other mutant lines as in wild-type flies. This, so-called "temperature compensation" ability is compromised in the mutant timeless allele "ritsu" (timrit ), and, as we show here, also in the timblind allele, mapping to the same region of TIM. To test if this region of TIM is indeed important for temperature compensation, we generated a collection of new mutants and mapped functional protein domains involved in the regulation of τ and in general clock function. We developed a protocol for targeted mutagenesis of specific gene regions utilizing the CRISPR/Cas9 technology, followed by behavioral screening. In this pilot study, we identified 20 new timeless mutant alleles with various impairments of temperature compensation. Molecular characterization revealed that the mutations included short in-frame insertions, deletions, or substitutions of a few amino acids resulting from the non-homologous end joining repair process. Our protocol is a fast and cost-efficient systematic approach for functional analysis of protein-coding genes and promoter analysis in vivo. Interestingly, several mutations with a strong temperature compensation defect map to one specific region of TIM. Although the exact mechanism of how these mutations affect TIM function is as yet unknown, our in silico analysis suggests they affect a putative nuclear export signal (NES) and phosphorylation sites of TIM. Immunostaining for PER was performed on two TIM mutants that display longer τ at 25°C and complete arrhythmicity at 28°C. Consistently with the behavioral phenotype, PER immunoreactivity was reduced in circadian clock neurons of flies exposed to elevated temperatures.
- Publikační typ
- časopisecké články MeSH
The circadian transcription of the tim gene is tightly regulated by the protein complex dCLK/CYC, which directly interacts with a series of closely spaced E-box and E-box-like elements in the Drosophila timeless promoter. The tim promoter from D. melanogaster has been studied in detail both in tissue cultures and in living flies yet has never been investigated in other species. This article presents a detailed functional analysis of the tim promoter from the drosophilid fly, Chymomyza costata, in Drosophila tissue cultures. A comparison of tim promoters from wt and npd-mutants confirmed that the 1855 bp deletion in the latter removes crucial regulatory cis-elements as well as the minimal promoter, being subsequently responsible for the lack of tim mRNA expression. Deletion and substitution mutations of the wt tim promoter showed that the region containing the canonical E-box, TER-box, and 2 incomplete E-box sequences is essential for CLK/CYC-mediated expression, while the PERR element appears to be a repressor in S2 cells. Furthermore, the expression of the circadian genes timeless, period , vrille, and doubletime was quantified in C. costata adults. Striking differences were found in expression profiles for tim, per, and vri between wild-type and npd-mutant individuals.
- MeSH
- buněčné linie MeSH
- cirkadiánní hodiny genetika MeSH
- Drosophila melanogaster cytologie genetika MeSH
- Drosophilidae genetika MeSH
- druhová specificita MeSH
- elementy E-Box genetika MeSH
- genetická transkripce MeSH
- hmyzí proteiny genetika MeSH
- molekulární sekvence - údaje MeSH
- mutace MeSH
- promotorové oblasti (genetika) genetika MeSH
- proteiny Drosophily genetika MeSH
- sekvence nukleotidů MeSH
- sekvenční homologie nukleových kyselin MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Homologous circadian genes are found in all insect clocks, but their contribution to species-specific circadian timing systems differs. The aim of this study was to extend research within Lepidoptera to gain a better understanding of the molecular mechanism underlying circadian clock plasticity and evolution. The Mediterranean flour moth, Ephestia kuehniella (Pyralidae), represents a phylogenetically ancestral lepidopteran species. We have identified circadian rhythms in egg hatching, adult emergence, and adult locomotor activity. Cloning full-length complementary DNAs and further characterization confirmed one copy of period and timeless genes in both sexes. Both per and tim transcripts oscillate in their abundance in E. kuehniella heads under light-dark conditions. PER-like immunoreactivity (PER-lir) was observed in nuclei and cytoplasm of most neurons in the central brain, the ventral part of subesophageal complex, the neurohemal organs, the optic lobes, and eyes. PER-lir in photoreceptor nuclei oscillated during the day with maximal intensity in the light phase of the photoperiodic regime and lack of a signal in the middle of the dark phase. Expression patterns of per and tim messenger RNAs (mRNAs) were revealed in the identical location as the PER-lir was detected. In the photoreceptors, a daily rhythm in the intensity of expression of both per mRNA and tim mRNA was found. These findings suggest E. kuehniella as a potential lepidopteran model for circadian studies.
- MeSH
- biologické hodiny genetika MeSH
- cirkadiánní hodiny genetika MeSH
- cirkadiánní proteiny Period genetika metabolismus MeSH
- cirkadiánní rytmus genetika fyziologie MeSH
- fenotyp MeSH
- fotoperioda MeSH
- hmyzí proteiny genetika MeSH
- hybridizace in situ MeSH
- imunohistochemie MeSH
- jaderné proteiny metabolismus MeSH
- klonování organismů MeSH
- komplementární DNA MeSH
- messenger RNA genetika metabolismus MeSH
- mozek metabolismus MeSH
- můry genetika růst a vývoj fyziologie MeSH
- regulace genové exprese MeSH
- sekvenční analýza DNA MeSH
- světlo MeSH
- zrakový lalok nesavčí fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
1st ed. xiv, 192 s.
Elevated levels of reactive oxygen species (ROS) reduce replication fork velocity by causing dissociation of the TIMELESS-TIPIN complex from the replisome. Here, we show that ROS generated by exposure of human cells to the ribonucleotide reductase inhibitor hydroxyurea (HU) promote replication fork reversal in a manner dependent on active transcription and formation of co-transcriptional RNA:DNA hybrids (R-loops). The frequency of R-loop-dependent fork stalling events is also increased after TIMELESS depletion or a partial inhibition of replicative DNA polymerases by aphidicolin, suggesting that this phenomenon is due to a global replication slowdown. In contrast, replication arrest caused by HU-induced depletion of deoxynucleotides does not induce fork reversal but, if allowed to persist, leads to extensive R-loop-independent DNA breakage during S-phase. Our work reveals a link between oxidative stress and transcription-replication interference that causes genomic alterations recurrently found in human cancer.
- MeSH
- DNA vazebné proteiny * metabolismus MeSH
- DNA MeSH
- hydroxymočovina farmakologie MeSH
- lidé MeSH
- reaktivní formy kyslíku MeSH
- replikace DNA * MeSH
- S fáze genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
346 s. : 24 cm il. ;
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. While period (per) mRNA peaked earlier under low temperatures, no temperature-dependent splicing of the last per 3' end intron was identified. The expression of timeless, vrille, and Par domain protein 1 was also influenced by temperature, each in a different manner. Our data indicated that comparable behavioral trends in daily activity distribution have evolved in Drosophila melanogaster and M. domestica, yet the behaviors of these two species are orchestrated by different molecular mechanisms.
- MeSH
- 3' nepřekládaná oblast genetika MeSH
- časové faktory MeSH
- cirkadiánní rytmus genetika MeSH
- Drosophila melanogaster genetika MeSH
- exony genetika MeSH
- fotoperioda MeSH
- fylogeneze MeSH
- hmyzí geny * MeSH
- introny genetika MeSH
- kondiční příprava zvířat MeSH
- kryptochromy genetika MeSH
- messenger RNA genetika metabolismus MeSH
- moucha domácí MeSH
- pohybová aktivita MeSH
- promotorové oblasti (genetika) genetika MeSH
- regulace genové exprese MeSH
- sestřih RNA genetika MeSH
- teplota * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Olympism, though a timeless ideal, was given shape in the late 19th century, by Baron Pierre de Coubertin and retains its sense of relevance in the 21st century, not least in the form of educational syllabi. This paper aims to critically present ideas and practices in the implementation of “Olympic Education†that were attempted for the first time at the Department of Education at the University of Cyprus during the academic year 2008-2009. The course was designed to assist students to increase their awareness of sport as a means not only to develop into top level athletes, but also to become good citizens and women and men of peace. Consistent with the aim of Olympic Education programmes to promote the cultivation of the body in parallel with the exercise and expansion of mental activities and capabilities, this paper argues that there is a demonstrable need to design and develop such courses as can be implemented for diverse groups. We conclude that efforts to implement “Olympic Education†programmes at a tertiary level may be beneficial in the dissemination of Olympic ideals and the harmonious, balanced and all-round development of students.
- Klíčová slova
- terciální vzdělávání, olympijská výchova, kurz,
- MeSH
- kurikulum * MeSH
- lidé MeSH
- mínění MeSH
- průzkumy a dotazníky MeSH
- šíření informací MeSH
- sporty * dějiny etika výchova MeSH
- studenti MeSH
- univerzity * MeSH
- výchova a vzdělávání metody MeSH
- vyučování MeSH
- výuka - hodnocení MeSH
- znalosti MeSH
- Check Tag
- lidé MeSH
- Geografické názvy
- Kypr MeSH
Discussions on questions and problems of medical ethics are on everyone's lips. The debates center for instance around the just allocation of public resources, demographical changes in our society or the guarantee of patient autonomy, thus posing questions on the technical progress in modern medicine. These contemporary conflicts in medicine are numerous, but not all of them are new; rather, the discussion in medical ethics on these dilemmas is bound to contexts and has historical roots. Some of these conflicts reach back to the medicine of the Renaissance and Antiquity, thus assigning actuality to the historical viewpoint. Taking history into account, one can benefit from a timeless content and not least get a feeling for historicity and contingency. Considering the creation of identity, the old authorities also represent central normative reference points for the ethical competence of physicians understood as an attitude within an interpersonal medicine. For this reason, the heritage of Hippocrates, which encompasses values and norms of the Hippocratic Oath, needs to be respected. Apart from other dimensions of knowledge and skills, the development of an individual ethical competence also requires awareness of the past, leading to an understanding for the historical, social and cultural relativity of medical action.
- MeSH
- bioetická témata dějiny MeSH
- dějiny 15. století MeSH
- dějiny starověku MeSH
- filosofie lékařská MeSH
- lékařská etika dějiny MeSH
- lidé MeSH
- Check Tag
- dějiny 15. století MeSH
- dějiny starověku MeSH
- lidé MeSH
- Publikační typ
- historické články MeSH
- přehledy MeSH
- Geografické názvy
- Německo MeSH
The Ido philosophy is a proposal to clarify the meaning of today's warrior pathway. The author tries to answer the following questions: In what way should we understand epistemology? How do we describe the human being and the phenomenon of martial arts? What is the meaning of the terms ‘idō' and ‘Idōkan'? What ethics, values and rules are prominent in the Ido? What is the specific, symbolic content of the Ido? This is a single case study, involving a content analysis of literature and the wider discourse, and the hermeneutic phenomenology. Epistemology is understood here as a way of understanding the martial arts by the practitioner, and as a way of reaching the truth about the philosophy of martial arts. In both cases it is the practice that is their own psychophysical experience. Man and the phenomenon of martial arts (ontology) here we treat holistically. ‘Ido' is an ambiguous concept, but in Ido philosophy we understand it in the first place as the principle of ‘continuous movement'. The prevailing ethic is derivative of the tradition of chivalry, which is also accented in symbolism. The Ido philosophy, as an anthropology of martial arts and today's Warrior Way, draws from the wisdom of the East and the West, but not uncritically. Normative ethics realizes the ideals of nobility, as Homo Creator Nobilis. This indicates the way in which value requires great effort, self-discipline and perseverance. It focuses especially on timeless, higher values, such as fidelity, truth, and the pursuit of wisdom.
