scholarly journals Chronobiology and the design of marine biology experiments

2018 ◽  
Vol 76 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Audrey M Mat
Keyword(s):  
Marine Biology ◽  
Clock Genes ◽  
Biological Rhythms ◽  
Marine Species ◽  
Temporal Organization ◽  
Biological Clocks ◽  
Solar Cycles ◽  
Dark Cycle ◽  
Marine Habitats ◽  
Selection Of

AbstractMarine habitats are shaped by several geophysical cycles ranging from a few hours (tidal and solar cycles) to a year (seasons). These cycles have favoured the selection of endogenous biological clocks. Such a clock is a molecular time-keeping mechanism that consists of a set of core clock genes whose expression oscillates. The clocks produce biological rhythms and influence virtually all metabolic, physiological, and behavioural functions in organisms. This work highlights the importance to take chronobiology into account in experimental marine biology to avoid faulty results, misinterpretation of results, and/or to strengthen observations and conclusion. A literature survey, based on 150 articles, was conducted and showed that, despite the pervasive imprint of biological rhythms in marine species, environmental cycles such as the 24 h-light/dark cycle and the seasonality are rarely considered in experimental designs. This work emphasizes that better integrating the temporal organization and regulation of marine species within the marine biology community is essential for obtaining representative results.

scholarly journals Review: Chronopharmacology; A Biological Rhythm

2021 ◽  
Vol 23 (12) ◽  
pp. 60-82
Author(s):  
Pooja P. Dahale ◽  
◽  
Mr. Vijay R. Chakote ◽  
Siddesh V Rokade ◽  
Shrikant C. Bhosale ◽  
...  
Keyword(s):  
Biological Rhythms ◽  
Temporal Variations ◽  
External Factors ◽  
Temporal Organization ◽  
Time Dependent ◽  
Peak Time ◽  
Toxic Substances ◽  
Biological Clocks ◽  
Scientific Domain ◽  
Physiological Variables

Chronopharmacology is the study of how the effects of drugs vary with biological timing and endogenous periodicities. The goal is to improve our understanding of periodic and thus predictable (e.g. circadian) changes in both desired effects (chronoeffectiveness) and tolerance (chronotolerance) of medications. Dosing time-dependent changes also include quantification of parameters characterizing endogenous circadian rhythms (CR), in terms of pharmacologic effects, e.g. the 24-h adjusted mean (M), the period , the amplitude (A, the peak-to-trough difference), and the acrophase , the peak time location in the 24-h scale). Chronopharmacology became recognized as a scientific domain of investigation only in the early 1970s. For conventionally trained pharmacologists, it was not clear that predictable temporal variations of effects and disposition of agents (e.g. medications, hormones, and toxic substances) are governed by endogenous biological rhythms rather than by changes of external factors. On the 24-h scale (as well as on the yearly scale) there are peaks and troughs of physiological variables that are not randomly distributed; their respective locations correspond to a temporal organization controlled by a set of pacemakers (so-called biological clocks) became recognized as a scientific domain of investigation only in the early 1970s.

scholarly journals Concepts in human biological rhythms

2003 ◽  
Vol 5 (4) ◽  
pp. 327-342 ◽  
Keyword(s):  
Experimental Data ◽  
Genetic Model ◽  
Clinical Symptoms ◽  
Night Shift ◽  
Biological Rhythms ◽  
Temporal Organization ◽  
Biological Clocks ◽  
Shift Workers ◽  
Left Hand ◽  
The Right

Biological rhythms and their temporal organization are adaptive phenomena to periodic changes in environmental factors linked to the earth's rotation on its axis and around the sun. Experimental data from the plant and animal kingdoms have led to many models and concepts related to biological clocks that help describe and understand the mechanisms of these changes. Many of the prevailing concepts apply to all organisms, but most of the experimental data are insufficient to explain the dynamics of human biological clocks. This review presents phenomena thai are mainly characteristic ofand unique to - human chronobiology, and which cannot be fully explained by concepts and models drawn from laboratory experiments. We deal with the functional advantages of the human temporal organization and the problem of desynchronization, with special reference to the period (τ) of the circadian rhythm and its interindividual and intraindividual variability. We describe the differences between right- and left-hand rhythms suggesting the existence of different biological clocks in the right and left cortices, Desynchronization of rhythms is rather frequent (one example is night shift workers). In some individuals, desynchronization causes no clinical symptoms and we propose the concept of "allochronism" to designate a variant of the human temporal organization with no pathological implications. We restrict the term "dyschronism" to changes or alterations in temporal organization associated with a set of symptoms similar to those observed in subjects intolerant to shift work, eg, persisting fatigue and mood and sleep alterations. Many diseases involve chronic deprivation of sleep at night and constitute conditions mimicking thai of night shift workers who are intolerant to desynchronization. We also present a genetic model (the dian-circadian model) to explain interindividual differences in the period of biological rhythms in certain conditions.

Long-lived αMUPA transgenic mice exhibit pronounced circadian rhythms

2006 ◽  
Vol 291 (5) ◽  
pp. E1017-E1024 ◽  
Author(s):  
Oren Froy ◽  
Nava Chapnik ◽  
Ruth Miskin
Keyword(s):  
Food Intake ◽  
Transgenic Mice ◽  
Life Span ◽  
Food Consumption ◽  
Clock Genes ◽  
Biological Clock ◽  
Biological Rhythms ◽  
Pcr Analysis ◽  
Biological Clocks ◽  
Clock Gene Expression

Robust biological rhythms have been shown to affect life span. Biological clocks can be entrained by two feeding regimens, restricted feeding (RF) and caloric restriction (CR). RF restricts the time of food availability, whereas CR restricts the amount of calories with temporal food consumption. CR is known to retard aging and extend life span of animals via yet-unknown pathways. We hypothesize that resetting the biological clock could be one possible mechanism by which CR extends life span. Because it is experimentally difficult to uncouple calorie reduction from temporal food consumption, we took advantage of the murine urokinase-like plasminogen activator (αMUPA) transgenic mice overexpressing a serine protease implicated in brain development and plasticity; they exhibit spontaneously reduced eating and increased life span. Quantitative real-time PCR analysis revealed that αMUPA mice exhibit robust expression of the clock genes mPer1, mPer2, mClock, and mCry1 but not mBmal1 in the liver. We also found changes in the circadian amplitude and/or phase of clock-controlled output systems, such as feeding behavior, body temperature, and enteric cryptdin expression. A change in the light-dark regimen led to modified clock gene expression and abrogated circadian patterns of food intake in wild-type (WT) and αMUPA mice. Consequently, food consumption of WT mice increased, whereas that of αMUPA mice remained the same, indicating that reduced food intake occurs upstream and independently of the biological clock. Thus we surmise that CR could lead to pronounced and synchronized biological rhythms. Because the biological clock controls mitochondrial, hormonal, and physiological parameters, system synchronicity could lead to extended life span.

THE ROLE OF CIRCADIAN REGULATION OF GHRELIN LEVELS IN PARKINSON’S DISEASE (LITERATURE REVIEW)

2021 ◽  
Vol 74 (7) ◽  
pp. 1750-1753
Author(s):  
Kateryna A. Tarianyk ◽  
Nataliya V. Lytvynenko ◽  
Anastasiia D. Shkodina ◽  
Igor P. Kaidashev
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Clock Genes ◽  
Biological Rhythms ◽  
Circadian Regulation ◽  
Diurnal Changes ◽  
Dopaminergic Therapy ◽  
Peripheral Oscillators ◽  
Genes Expression

The paper is aimed at the analysis of the role of the circadian regulation of ghrelin levels in patients with Parkinson’s disease. Based on the literature data, patients with Parkinson’s disease have clinical fluctuations in the symptoms of the disease, manifested by the diurnal changes in motor activity, autonomic functions, sleep-wake cycle, visual function, and the efficacy of dopaminergic therapy. Biological rhythms are controlled by central and peripheral oscillators which links with dopaminergic neurotransmission – core of the pathogenesis of Parkinson`s disease. Circadian system is altered in Parkinson`s disease due to that ghrelin fluctuations may be changed. Ghrelin is potential food-entrainable oscillator because it is linked with clock genes expression. In Parkinson`s disease this hormone may induce eating behavior changing and as a result metabolic disorder. The “hunger hormone” ghrelin can be a biomarker of the Parkinson’s disease, and the study of its role in the pathogenesis, as well as its dependence on the period of the day, intake of levodopa medications to improve the effectiveness of treatment is promising.

scholarly journals Daily rhythms in gene expression of the human parasite Schistosoma mansoni

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Kate A. Rawlinson ◽  
Adam J. Reid ◽  
Zhigang Lu ◽  
Patrick Driguez ◽  
Anna Wawer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Schistosoma Mansoni ◽  
Circadian Clock ◽  
Drug Targets ◽  
Clock Genes ◽  
Biological Rhythms ◽  
Active Phase ◽  
Egg Laying ◽  
Daily Rhythms ◽  
Metazoan Parasites

Abstract Background The consequences of the earth’s daily rotation have led to 24-h biological rhythms in most organisms. Even some parasites are known to have daily rhythms, which, when in synchrony with host rhythms, can optimise their fitness. Understanding these rhythms may enable the development of control strategies that take advantage of rhythmic vulnerabilities. Recent work on protozoan parasites has revealed 24-h rhythms in gene expression, drug sensitivity and the presence of an intrinsic circadian clock; however, similar studies on metazoan parasites are lacking. To address this, we investigated if a metazoan parasite has daily molecular oscillations, whether they reveal how these longer-lived organisms can survive host daily cycles over a lifespan of many years and if animal circadian clock genes are present and rhythmic. We addressed these questions using the human blood fluke Schistosoma mansoni that lives in the vasculature for decades and causes the tropical disease schistosomiasis. Results Using round-the-clock transcriptomics of male and female adult worms collected from experimentally infected mice, we discovered that ~ 2% of its genes followed a daily pattern of expression. Rhythmic processes included a stress response during the host’s active phase and a ‘peak in metabolic activity’ during the host’s resting phase. Transcriptional profiles in the female reproductive system were mirrored by daily patterns in egg laying (eggs are the main drivers of the host pathology). Genes cycling with the highest amplitudes include predicted drug targets and a vaccine candidate. These 24-h rhythms may be driven by host rhythms and/or generated by a circadian clock; however, orthologs of core clock genes are missing and secondary clock genes show no 24-h rhythmicity. Conclusions There are daily rhythms in the transcriptomes of adult S. mansoni, but they appear less pronounced than in other organisms. The rhythms reveal temporally compartmentalised internal processes and host interactions relevant to within-host survival and between-host transmission. Our findings suggest that if these daily rhythms are generated by an intrinsic circadian clock then the oscillatory mechanism must be distinct from that in other animals. We have shown which transcripts oscillate at this temporal scale and this will benefit the development and delivery of treatments against schistosomiasis.

scholarly journals Chronotype: what role in the context of gastroenteropancreatic neuroendocrine tumors?

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Luigi Barrea ◽  
Giovanna Muscogiuri ◽  
Gabriella Pugliese ◽  
Roberta Modica ◽  
Daniela Laudisio ◽  
...  
Keyword(s):  
Neuroendocrine Tumors ◽  
Metabolic Profile ◽  
Progressive Disease ◽  
Biological Rhythms ◽  
Tumor Aggressiveness ◽  
Dark Cycle ◽  
Gastroenteropancreatic Neuroendocrine Tumors ◽  
Pathological Characteristics ◽  
Increased Risk ◽  
The Subject

Abstract Background Chronotype is defined as a trait determining the subject circadian preference in behavioral and biological rhythms relative to external light–dark cycle. Although individual differences in chronotype have been associated with an increased risk of developing some types of cancer, no studies have been carried out in gastroenteropancreatic neuroendocrine tumors (GEP-NET). Materials We investigate the differences in chronotype between 109 GEP-NET and 109 healthy subjects, gender-, age-, and BMI-matched; and its correlation with tumor aggressiveness. Results GEP-NET patients have a lower chronotype score (p = 0.035) and a higher percentage of evening chronotype (p = 0.003) than controls. GEP-NET patients with morning chronotype had lower BMI, waist circumference, and higher percentage of MetS (p < 0.001) than evening type. Interestingly, considering the clinical pathological characteristics, patients with the presence of metastasis, grading G2, and in progressive disease presented the lower chronotype score (p = 0.004, p < 0.001, and p = 0.002; respectively) compared to other categories. Chronotype score was negatively associated with anthropometric measurements, metabolic profile, percentage of MetS, and Ki67 index (p < 0.001 for all). Conclusions GEP-NET patients have an unhealthy metabolic profile and present more commonly an evening chronotype. These results support the importance of including the assessment of chronotype in an adjunctive tool for the prevention of metabolic alterations and tumor aggressiveness of GEP-NET.

scholarly journals The Role of Endogenous Carbon Monoxide (CO) in the Functioning of Biological Clocks in Pig and Wild Boar Hybrids During Long- and Short-day Seasons

2021 ◽  
Author(s):  
Przemysław GILUN ◽  
Barbara Wąsowska ◽  
Magdalena Sowa-Kućma ◽  
Katarzyna Kozioł ◽  
Maria Romerowicz-Misielak ◽  
...  
Keyword(s):  
Gene Expression ◽  
Wild Boar ◽  
Clock Genes ◽  
Autologous Blood ◽  
Biological Clock ◽  
Biological Clocks ◽  
Light Emitting ◽  
Short Day ◽  
The Right ◽  
Induced Changes

Abstract Mature males of a wild boar-pig crossbreed during long- and short-day seasons were used for the study, which demonstrated that the chemical light carrier CO regulates the expression of biological clock genes in the hypothalamus (preoptic area - POA and dorsal part of hypothalamus - DH) via humoral pathways. Autologous blood with experimentally elevated concentrations of endogenous CO (using lamps with white light-emitting diodes) was infused into the ophthalmic venous sinus via the right dorsal nasal vein.The results showed that elevated endogenous CO levels through blood irradiation induced changes in gene expression involved in the functioning of the main biological clock. Changes in the expression of the transcription factors Bmal1, Clock and Npas2 had a similar pattern in both structures, where a very large decrease in gene expression was shown after exposure to elevated endogenous CO levels. The changes in the gene expression of PER 1-2, CRY 1-2, REV-ERB α-β and ROR β are not the same for both POA and DH hypothalamic structures, indicating that both structures respond differently to the received humoral signal.The obtained results indicate that CO is a chemical light molecule whose production in organisms depends on the amount of light. An adequate amount of light is an essential factor for the proper functioning of the main biological clock.

New and little-known marine species of Pinaciophora, Rabdiaster and Thomseniophora gen. nov. (Rotosphaerida: Pompholyxophryidae)

2012 ◽  
Vol 93 (5) ◽  
pp. 1211-1229 ◽  
Author(s):  
Kenneth H. Nicholls
Keyword(s):  
Pacific Ocean ◽  
New Genus ◽  
Marine Species ◽  
Single Type ◽  
Haida Gwaii ◽  
Western Atlantic ◽  
Queen Charlotte Islands ◽  
Marine Habitats ◽  
Near Shore ◽  
One New Species

Near-shore benthic sediment samples collected at low tide from the western Atlantic Ocean (Sable Island, Nova Scotia, Canada) and the eastern Pacific Ocean (Haida Gwaii (Queen Charlotte Islands), British Columbia, Canada) were searched for little-known species of the rhizarian (Cercozoa) genera Pinaciophora, Rabdiaster and other related rotosphaerids. Several representatives with complete investitures of silica-scales (the structure of which is taxonomically diagnostic) were studied by transmission and scanning electron microscopy. The validity of the genus Pinaciophora (sensu Penard, 1904) as defined by a single type of plate-scale only, was strengthened by the discovery of Pinaciophora rubicunda and of another previously undescribed entity, both of which lacked spine-scales. Several earlier reports of loose scales from marine habitats, and erroneously identified as the freshwater P. fluviatilis, might be assigned to P. marina sp. nov. The new genus Thomseniophora was erected to include all ‘Pinaciophora' previously known to produce spine-scales and seven new taxa were described. Six other little-known species of Thomseniophora, Pinaciophora and Rabdiaster were described from the Canadian west coast (Pacific Ocean) including one new species of Pinaciophora. The addition of Thomseniophora brings the number of genera assigned to the Rotosphaerida to six: Pinaciophora, Thomseniophora, Rabdiaster, Rabdiophrys and Pompholyxophrys. The presence of several apparently closely related taxa in the same collection (same location and sampling date) strengthens the conclusion that relatively small differences in the morphology of their siliceous scales were more likely caused by genetic differences than by environmental influences.

scholarly journals Minireview: The Circadian Clockwork of the Suprachiasmatic Nuclei—Analysis of a Cellular Oscillator that Drives Endocrine Rhythms

Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 5624-5634 ◽  
Author(s):  
Elizabeth S. Maywood ◽  
John S. O’Neill ◽  
Johanna E. Chesham ◽  
Michael H. Hastings
Keyword(s):  
Neural Circuits ◽  
Clock Genes ◽  
Time Base ◽  
Suprachiasmatic Nuclei ◽  
Dark Cycle ◽  
Cellular Mechanisms ◽  
Circadian Control ◽  
Daily Cycles ◽  
Central Clock ◽  
Retinal Afferents

The secretion of hormones is temporally precise and periodic, oscillating over hours, days, and months. The circadian timekeeper within the suprachiasmatic nuclei (SCN) is central to this coordination, modulating the frequency of pulsatile release, maintaining daily cycles of secretion, and defining the time base for longer-term rhythms. This central clock is driven by cell-autonomous, transcriptional/posttranslational feedback loops incorporating Period (Per) and other clock genes. SCN neurons exist, however, within neural circuits, and an unresolved question is how SCN clock cells interact. By monitoring the SCN molecular clockwork using fluorescence and bioluminescence videomicroscopy of organotypic slices from mPer1::GFP and mPer1::luciferase transgenic mice, we show that interneuronal neuropeptidergic signaling via the vasoactive intestinal peptide (VIP)/PACAP2 (VPAC2) receptor for VIP (an abundant SCN neuropeptide) is necessary to maintain both the amplitude and the synchrony of clock cells in the SCN. Acute induction of mPer1 by light is, however, independent of VIP/VPAC2 signaling, demonstrating dissociation between cellular mechanisms mediating circadian control of the clockwork and those mediating its retinally dependent entrainment to the light/dark cycle. The latter likely involves the Ca2+/cAMP response elements of mPer genes, triggered by a MAPK cascade activated by retinal afferents to the SCN. In the absence of VPAC2 signaling, however, this cascade is inappropriately responsive to light during circadian daytime. Hence VPAC2-mediated signaling sustains the SCN cellular clockwork and is necessary both for interneuronal synchronization and appropriate entrainment to the light/dark cycle. In its absence, behavioral and endocrine rhythms are severely compromised.

scholarly journals Genetic variation and phenotypic plasticity in circadian rhythms in an armed beetle, Gnatocerus cornutus (Tenebrionidae)

2020 ◽  
Vol 130 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Kentarou Matsumura ◽  
Masato S Abe ◽  
Manmohan D Sharma ◽  
David J Hosken ◽  
Taishi Yoshii ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Phenotypic Plasticity ◽  
Circadian Rhythms ◽  
Temperature Effects ◽  
Temperature Compensation ◽  
Biological Rhythms ◽  
Total Activity ◽  
Biological Clocks ◽  
Isofemale Lines ◽  
Free Running

Abstract Circadian rhythms, their free-running periods and the power of the rhythms are often used as indicators of biological clocks, and there is evidence that the free-running periods of circadian rhythms are not affected by environmental factors, such as temperature. However, there are few studies of environmental effects on the power of the rhythms, and it is not clear whether temperature compensation is universal. Additionally, genetic variation and phenotypic plasticity in biological clocks are important for understanding the evolution of biological rhythms, but genetic and plastic effects are rarely investigated. Here, we used 18 isofemale lines (genotypes) of Gnatocerus cornutus to assess rhythms of locomotor activity, while also testing for temperature effects. We found that total activity and the power of the circadian rhythm were affected by interactions between sex and genotype or between sex, genotype and temperature. The males tended to be more active and showed greater increases in activity, but this effect varied across both genotypes and temperatures. The period of activity varied only by genotype and was thus independent of temperature. The complicated genotype–sex–environment interactions we recorded stress the importance of investigating circadian activity in more integrated ways.

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