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1.
PLoS One ; 15(9): e0237716, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32886676

RESUMO

Bull trout (Salvelinus confluentus) are challenging to detect as a result of the species cryptic behavior and coloration, relatively low densities in complex habitats, and affinity for cold, high clarity, low conductivity waters. Bull trout are also closely associated with the stream bed, frequently conceal in substrate, and this concealment behavior is poorly understood. Consequently, population assessments are problematic and biologists and managers often lack quantitative information to accurately describe bull trout distributions, estimate abundance, and assess status and trends; particularly for stream-dwelling populations. During controlled laboratory trials, we recorded concealment, resting, and swimming behavior of juvenile wild bull trout in response to: (1) constant and fluctuating water temperature, (2) presence or absence of light, and (3) substrate size. Light level had the strongest influence on wild fish concealment and more fish concealed as light levels increased from darkness to daylight. Wild fish were 14.5 times less likely to conceal in constant darkness and 4.1 times more likely to conceal in 12 h light x 12 h darkness compared to constant light. Wild fish were 6.2 times less likely to conceal in small (26-51 mm) substrate compared to larger (52-102 mm) substrate. As water temperature increased, fewer wild fish concealed. Knowledge of wild bull trout concealment will improve field sampling protocols and increase detection efficiencies. These data also enhance knowledge of bull trout niche requirements which illuminates ecological differences among species and informs conservation and restoration efforts.


Assuntos
Truta/fisiologia , Distribuição Animal , Animais , Comportamento Animal , Fotoperíodo , Rios/química , Natação , Temperatura
2.
Rev Med Suisse ; 16(707): 1745-1747, 2020 Sep 23.
Artigo em Francês | MEDLINE | ID: mdl-32969610

RESUMO

Circadian rhythmicity generated by the biological clock structures the functioning of human beings over a period of almost 24 hours. This clock is entrained daily by internal and external cues among which light is the most powerful. Several disturbances, whether clinical or biological, observed in bipolar disorders are suggestive of a disruption of the circadian rhythm. Thus, treatments that modulate the biological clock have been developed. So far, the results of light therapy are not unanimous and invite us to better specify the treatment modalities. Dark therapy is a promising intervention that is still not much studied nowadays and therefore opens up great prospects for research in the future.


Assuntos
Transtorno Bipolar/psicologia , Escuridão , Luz , Fotoperíodo , Relógios Biológicos/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Humanos
3.
PLoS One ; 15(8): e0232733, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764762

RESUMO

Ferrets (Mustela putorius furo) are a valuable animal model used in biomedical research. Like many animals, ferrets undergo significant variation in body weight seasonally, affected by photoperiod, and these variations complicate the use weight as an indicator of health status. To overcome this requires a better understanding of these seasonal weight changes. We provide a normative weight data set for the female ferret accounting for seasonal changes, and also investigate the effect of fluid regulation on weight change. Female ferrets (n = 39) underwent behavioural testing from May 2017 to August 2019 and were weighed daily, while housed in an animal care facility with controlled light exposure. In the winter (October to March), animals experienced 10 hours of light and 14 hours of dark, while in summer (March to October), this contingency was reversed. Individual animals varied in their body weight from approximately 700 to 1200 g. However, weights fluctuated with light cycle, with animals losing weight in summer, and gaining weight in winter such that they fluctuated between approximately 80% and 120% of their long-term average. Ferrets were weighed as part of their health assessment while experiencing water regulation for behavioural training. Water regulation superimposed additional weight changes on these seasonal fluctuations, with weight loss during the 5-day water regulation period being greater in summer than winter. Analysing the data with a Generalised Linear Model confirmed that the percentage decrease in weight per week was relatively constant throughout the summer months, while the percentage increase in body weight per week in winter decreased through the season. Finally, we noted that the timing of oestrus was reliably triggered by the increase in day length in spring. These data establish a normative benchmark for seasonal weight variation in female ferrets that can be incorporated into the health assessment of an animal's condition.


Assuntos
Peso Corporal , Furões/anatomia & histologia , Criação de Animais Domésticos , Animais , Animais de Laboratório/anatomia & histologia , Animais de Laboratório/fisiologia , Água Corporal/fisiologia , Estro/fisiologia , Feminino , Furões/fisiologia , Modelos Lineares , Modelos Animais , Modelos Biológicos , Fotoperíodo , Valores de Referência , Estações do Ano
4.
PLoS One ; 15(8): e0235930, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32750054

RESUMO

Circadian clocks control rhythms in physiology and behavior entrained to 24 h light-dark cycles. Despite of conserved general schemes, molecular circadian clockworks differ between insect species. With RNA interference (RNAi) we examined an ancient circadian clockwork in a basic insect, the hemimetabolous Madeira cockroach Rhyparobia maderae. With injections of double-stranded RNA (dsRNA) of cockroach period (Rm´per), timeless 1 (Rm´tim1), or cryptochrome 2 (Rm´cry2) we searched for essential components of the clock´s core negative feedback loop. Single injections of dsRNA of each clock gene into adult cockroaches successfully and permanently knocked down respective mRNA levels within ~two weeks deleting daytime-dependent mRNA rhythms for Rm´per and Rm´cry2. Rm´perRNAi or Rm´cry2RNAi affected total mRNA levels of both genes, while Rm´tim1 transcription was independent of both, also keeping rhythmic expression. Unexpectedly, circadian locomotor activity of most cockroaches remained rhythmic for each clock gene knockdown employed. It expressed weakened rhythms and unchanged periods for Rm´perRNAi and shorter periods for Rm´tim1RNAi and Rm´cry2RNAi.As a hypothesis of the cockroach´s molecular clockwork, a basic network of switched differential equations was developed to model the oscillatory behavior of clock cells expressing respective clock genes. Data were consistent with two synchronized main groups of coupled oscillator cells, a leading (morning) oscillator, or a lagging (evening) oscillator that couple via mutual inhibition. The morning oscillators express shorter, the evening oscillators longer endogenous periods based on core feedback loops with either PER, TIM1, or CRY2/PER complexes as dominant negative feedback of the clockwork. We hypothesize that dominant morning oscillator cells with shorter periods express PER, but not CRY2, or TIM1 as suppressor of clock gene expression, while two groups of evening oscillator cells with longer periods either comprise TIM1 or CRY2/PER suppressing complexes. Modelling suggests that there is an additional negative feedback next to Rm´PER in cockroach morning oscillator cells.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Baratas/fisiologia , Criptocromos/metabolismo , Proteínas de Insetos/metabolismo , Proteínas Circadianas Period/metabolismo , Animais , Proteínas de Ciclo Celular/genética , Relógios Circadianos , Ritmo Circadiano , Baratas/genética , Criptocromos/genética , Proteínas de Insetos/genética , Masculino , Proteínas Circadianas Period/genética , Fotoperíodo , Interferência de RNA
5.
Nat Commun ; 11(1): 4291, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32855407

RESUMO

The annual photoperiod cycle provides the critical environmental cue synchronizing rhythms of life in seasonal habitats. In 1936, Bünning proposed a circadian-based coincidence timer for photoperiodic synchronization in plants. Formal studies support the universality of this so-called coincidence timer, but we lack understanding of the mechanisms involved. Here we show in mammals that long photoperiods induce the circadian transcription factor BMAL2, in the pars tuberalis of the pituitary, and triggers summer biology through the eyes absent/thyrotrophin (EYA3/TSH) pathway. Conversely, long-duration melatonin signals on short photoperiods induce circadian repressors including DEC1, suppressing BMAL2 and the EYA3/TSH pathway, triggering winter biology. These actions are associated with progressive genome-wide changes in chromatin state, elaborating the effect of the circadian coincidence timer. Hence, circadian clock-pituitary epigenetic pathway interactions form the basis of the mammalian coincidence timer mechanism. Our results constitute a blueprint for circadian-based seasonal timekeeping in vertebrates.


Assuntos
Fatores de Transcrição ARNTL/genética , Relógios Circadianos/fisiologia , Fotoperíodo , Hipófise/fisiologia , Ovinos/fisiologia , Fatores de Transcrição ARNTL/metabolismo , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Epigênese Genética , Regulação da Expressão Gênica , Masculino , Melatonina/genética , Melatonina/metabolismo , Estações do Ano
6.
Curr Biol ; 30(16): R930-R931, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32810450

RESUMO

The COVID-19 pandemic [1] resulted in many countries imposing a lockdown, which in turn reduces sunlight exposure and alters daily social schedules. Since these are the main entrainment factors for biological rhythms [2], we hypothesized that the lockdown may have affected sleep and circadian rhythms. We indeed show that participants slept longer and later during lockdown weekdays, and exhibited lower levels of social jetlag. While this may seem to be an overall improvement of sleep conditions, chronotype was also delayed under the lockdown. This signature of a weaker light-dark cycle should be monitored attentively since it may progressively cause disruptive effects on sleep and circadian rhythms, affecting human performance and health [3].


Assuntos
Ritmo Circadiano , Infecções por Coronavirus/complicações , Pneumonia Viral/complicações , Quarentena/psicologia , Sono/fisiologia , Adulto , Argentina , Infecções por Coronavirus/epidemiologia , Humanos , Síndrome do Jet Lag/etiologia , Pessoa de Meia-Idade , Pandemias , Fotoperíodo , Pneumonia Viral/epidemiologia , Quarentena/métodos , Inquéritos e Questionários , Fatores de Tempo
7.
PLoS One ; 15(8): e0237149, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764774

RESUMO

PURPOSE: To investigate the association between daily sunlight exposure duration and diabetic retinopathy in Korean adults with diabetes. METHODS: This study used data from the 2008-2011 Korea National Health and Nutrition Examination Survey. Overall, 1,089 patients with diabetes aged >40 years were included. The duration of daily sunlight exposure was assessed via health interviews. Comprehensive ophthalmic evaluations, including standard retinal fundus photography after pupil dilation, were conducted. Diabetic retinopathy was graded using the modified Airlie House Classification. Multivariate logistic regression analysis was performed to analyze the association between daily sunlight exposure duration and the diagnosis of diabetic retinopathy and non-proliferative diabetic retinopathy. RESULTS: The risk of diabetic retinopathy was 2.66 times higher in the group with ≥5 h of daily sunlight exposure than in the group with less exposure after adjusting for risk factors such as duration of diabetes, serum hemoglobin A1c level, hypertension, and dyslipidemia (P = 0.023). Furthermore, the risk of non-proliferative diabetic retinopathy was 3.13 times higher in the group with ≥5 h of daily sunlight exposure than in the group with less exposure (P = 0.009). In patients with diabetes for <10 years, the risks of diabetic retinopathy and non-proliferative diabetic retinopathy were 4.26 and 4.82 times higher in the group with ≥5 h of daily sunlight exposure than the group with less exposure, respectively (P < 0.05). CONCLUSIONS: This study revealed that sunlight exposure for ≥5 h a day was significantly associated with an increased risk of diabetic retinopathy and non-proliferative diabetic retinopathy in Korean patients with diabetes. The risks were significantly higher in patients with diabetes for <10 years. Therefore, reducing daily sunlight exposure could be an early preventive strategy against diabetic retinopathy in people with diabetes.


Assuntos
Retinopatia Diabética/epidemiologia , Luz Solar/efeitos adversos , Idoso , Estudos Transversais , Retinopatia Diabética/diagnóstico , Retinopatia Diabética/etiologia , Retinopatia Diabética/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais/estatística & dados numéricos , Estresse Oxidativo/efeitos da radiação , Fotografação , Fotoperíodo , Prevalência , República da Coreia/epidemiologia , Retina/diagnóstico por imagem , Retina/efeitos da radiação , Fatores de Risco , Índice de Gravidade de Doença , Fatores de Tempo
8.
Nat Commun ; 11(1): 4214, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843632

RESUMO

Stomata are epidermal structures that modulate gas exchanges between plants and the atmosphere. The formation of stomata is regulated by multiple developmental and environmental signals, but how these signals are coordinated to control this process remains unclear. Here, we showed that the conserved energy sensor kinase SnRK1 promotes stomatal development under short-day photoperiod or in liquid culture conditions. Mutation of KIN10, the catalytic α-subunit of SnRK1, results in the decreased stomatal index; while overexpression of KIN10 significantly induces stomatal development. KIN10 displays the cell-type-specific subcellular location pattern. The nuclear-localized KIN10 proteins are highly enriched in the stomatal lineage cells to phosphorylate and stabilize SPEECHLESS, a master regulator of stomatal formation, thereby promoting stomatal development. Our work identifies a module links connecting the energy signaling and stomatal development and reveals that multiple regulatory mechanisms are in place for SnRK1 to modulate stomatal development in response to changing environments.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Estômatos de Plantas/genética , Fatores de Transcrição/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Microscopia Confocal , Mutação , Fosforilação , Fotoperíodo , Estômatos de Plantas/citologia , Estômatos de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estabilidade Proteica , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição/metabolismo
9.
PLoS One ; 15(8): e0238144, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32857790

RESUMO

The efficacy of auxinic herbicides, a valuable weed control tool for growers worldwide, has been shown to vary with the time of day in which applications are made. However, little is known about the mechanisms causing this phenomenon. Investigating the differential in planta behavior of these herbicides across different times of application may grant an ability to advise which properties of auxinic herbicides are desirable when applications must be made around the clock. Radiolabeled herbicide experiments demonstrated a likely increase in ATP-binding cassette subfamily B (ABCB)-mediated 2,4-D and dicamba transport in Palmer amaranth (Amaranthus palmeri S. Watson) at simulated dawn compared to mid-day, as dose response models indicated that many orders of magnitude higher concentrations of N-1-naphthylphthalamic acid (NPA) and verapamil, respectively, are required to inhibit translocation by 50% at simulated sunrise compared to mid-day. Gas chromatographic analysis displayed that ethylene evolution in A. palmeri was higher when dicamba was applied during mid-day compared to sunrise. Furthermore, it was found that inhibition of translocation via 2,3,5-triiodobenzoic acid (TIBA) resulted in an increased amount of 2,4-D-induced ethylene evolution at sunrise, and the inhibition of dicamba translocation via NPA reversed the difference in ethylene evolution across time of application. Dawn applications of these herbicides were associated with increased expression of a putative 9-cis-epoxycarotenoid dioxygenase biosynthesis gene NCED1, while there was a notable lack of trends observed across times of day and across herbicides with ACS1, encoding 1-aminocyclopropane-1-carboxylic acid synthase. Overall, this research indicates that translocation is differentially regulated via specific protein-level mechanisms across times of application, and that ethylene release, a chief phytotoxic process involved in the response to auxinic herbicides, is related to translocation. Furthermore, transcriptional regulation of abscisic acid involvement in phytotoxicity and/or translocation are suggested.


Assuntos
Amaranthus/efeitos dos fármacos , Amaranthus/fisiologia , Resistência a Herbicidas/fisiologia , Herbicidas/farmacologia , Fotoperíodo , Ácido 2,4-Diclorofenoxiacético/farmacologia , Dicamba/farmacologia , Relação Dose-Resposta a Droga , Etilenos/metabolismo , Ftalimidas/metabolismo , Proteínas de Plantas/metabolismo , Ácidos Tri-Iodobenzoicos/metabolismo , Verapamil/metabolismo
10.
PLoS One ; 15(8): e0237103, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32833965

RESUMO

The eastern red bat (Lasiurus borealis) is widely considered to be in decline, inspiring interest in identifying important habitats for conservation in the eastern United States. Unfortunately, knowledge of important day-roosting habitats is lacking for much of the species' range. We examined patterns of day-roost selection by male and female eastern red bats at two study sites in southeastern Ohio, U. S. A, to help fill this information gap. We radio-tagged 28 male and 25 female bats during the summers of 2016-2019 and located 53 male and 74 female roosts. Day-roost selection differed between sexes and study areas. In a mostly even-aged forest with significant historical disturbance, we found males and females roosting in trees located at higher elevations, with no clear selection based on tree or stand characteristics. Specifically, males selected trees with larger diameters located at lower, cooler elevations than females, which selected smaller diameter trees found at higher, warmer elevations. However, in a forest with less historical disturbance and more structural diversity, we found sexes differed in how they selected from available habitats. These data show that heterogeneity in environmental conditions can lead to different patterns in selection, even between sites located within a small geographic area. They also show that eastern red bats sexually segregate on the local landscape in the presence of diverse forest conditions but may not do so in the absence of such diversity. We recommend managing forests to maintain structural diversity across an elevational gradient to provide male and female eastern red bats with suitable day-roosting habitat in southeast Ohio.


Assuntos
Distribuição Animal , Quirópteros/fisiologia , Ecossistema , Animais , Feminino , Masculino , Fotoperíodo , Estações do Ano
11.
PLoS Genet ; 16(7): e1008882, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32673315

RESUMO

Expansion of the maize growing area was central for food security in temperate regions. In addition to the suppression of the short-day requirement for floral induction, it required breeding for a large range of flowering time that compensates the effect of South-North gradients of temperatures. Here we show the role of a novel florigen gene, ZCN12, in the latter adaptation in cooperation with ZCN8. Strong eQTLs of ZCN8 and ZCN12, measured in 327 maize lines, accounted for most of the genetic variance of flowering time in platform and field experiments. ZCN12 had a strong effect on flowering time of transgenic Arabidopsis thaliana plants; a path analysis showed that it directly affected maize flowering time together with ZCN8. The allelic composition at ZCN QTLs showed clear signs of selection by breeders. This suggests that florigens played a central role in ensuring a large range of flowering time, necessary for adaptation to temperate areas.


Assuntos
Adaptação Fisiológica/genética , Florígeno/metabolismo , Proteínas de Plantas/genética , Zea mays/genética , Aclimatação/genética , Temperatura Baixa , Flores/genética , Flores/crescimento & desenvolvimento , Humanos , Fotoperíodo , Proteínas de Plantas/metabolismo , Locos de Características Quantitativas/genética , Zea mays/crescimento & desenvolvimento
12.
Proc Biol Sci ; 287(1930): 20201017, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32605431

RESUMO

Seasonal disease and parasitic infection are common across organisms, including humans, and there is increasing evidence for intrinsic seasonal variation in immune systems. Changes are orchestrated through organisms' physiological clocks using cues such as day length. Ample research in diverse taxa has demonstrated multiple immune responses are modulated by photoperiod, but to date, there have been few experimental demonstrations that photoperiod cues alter susceptibility to infection. We investigated the interactions among photoperiod history, immunity and susceptibility in laboratory-bred three-spined stickleback (a long-day breeding fish) and its external, directly reproducing monogenean parasite Gyrodactylus gasterostei. We demonstrate that previous exposure to long-day photoperiods (PLD) increases susceptibility to infection relative to previous exposure to short days (PSD), and modifies the response to infection for the mucin gene muc2 and Treg cytokine foxp3a in skin tissues in an intermediate 12 L : 12 D photoperiod experimental trial. Expression of skin muc2 is reduced in PLD fish, and negatively associated with parasite abundance. We also observe inflammatory gene expression variation associated with natural inter-population variation in resistance, but find that photoperiod modulation of susceptibility is consistent across host populations. Thus, photoperiod modulation of the response to infection is important for host susceptibility, highlighting new mechanisms affecting seasonality of host-parasite interactions.


Assuntos
Sistema Imunitário/fisiologia , Doenças Parasitárias , Fotoperíodo , Smegmamorpha/imunologia , Adaptação Fisiológica , Animais , Doenças Transmissíveis , Doenças dos Peixes/imunologia , Peixes , Interações Hospedeiro-Parasita , Humanos , Imunidade , Masculino , Reprodução , Estações do Ano , Smegmamorpha/parasitologia , Trematódeos
13.
Proc Biol Sci ; 287(1931): 20201079, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32693726

RESUMO

The biological clock expresses circadian rhythms, whose endogenous period (tau) is close to 24 h. Daily resetting of the circadian clock to the 24 h natural photoperiod might induce marginal costs that would accumulate over time and forward affect fitness. It was proposed as the circadian resonance theory. For the first time, we aimed to evaluate these physiological and cognitive costs that would partially explain the mechanisms of the circadian resonance hypothesis. We evaluated the potential costs of imposing a 26 h photoperiodic regimen compared to the classical 24 h entrainment measuring several physiological and cognitive parameters (body temperature, energetic expenditure, oxidative stress, cognitive performances) in males of a non-human primate (Microcebus murinus), a nocturnal species whose endogenous period is about 23.5 h. We found significant higher resting body temperature and energy expenditure and lower cognitive performances when the photoperiodic cycle length was 26 h. Together these results suggest that a great deviation of external cycles from tau leads to daily greater energetic expenditure, and lower cognitive capacities. To our knowledge, this study is the first to highlight potential mechanisms of circadian resonance theory.


Assuntos
Cheirogaleidae/fisiologia , Ritmo Circadiano , Animais , Temperatura Corporal , Relógios Circadianos , Cognição , Masculino , Atividade Motora , Fotoperíodo , Vibração
14.
PLoS Genet ; 16(7): e1008812, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32658893

RESUMO

In Arabidopsis, CONSTANS (CO) integrates light and circadian clock signals to promote flowering under long days (LD). In the grasses, a duplication generated two paralogs designated as CONSTANS1 (CO1) and CONSTANS2 (CO2). Here we show that in tetraploid wheat plants grown under LD, combined loss-of-function mutations in the A and B-genome homeologs of CO1 and CO2 (co1 co2) result in a small (3 d) but significant (P<0.0001) acceleration of heading time both in PHOTOPERIOD1 (PPD1) sensitive (Ppd-A1b, functional ancestral allele) and insensitive (Ppd-A1a, functional dominant allele) backgrounds. Under short days (SD), co1 co2 mutants headed 13 d earlier than the wild type (P<0.0001) in the presence of Ppd-A1a. However, in the presence of Ppd-A1b, spikes from both genotypes failed to emerge by 180 d. These results indicate that CO1 and CO2 operate mainly as weak heading time repressors in both LD and SD. By contrast, in ppd1 mutants with loss-of-function mutations in both PPD1 homeologs, the wild type Co1 allele accelerated heading time >60 d relative to the co1 mutant allele under LD. We detected significant genetic interactions among CO1, CO2 and PPD1 genes on heading time, which were reflected in complex interactions at the transcriptional and protein levels. Loss-of-function mutations in PPD1 delayed heading more than combined co1 co2 mutations and, more importantly, PPD1 was able to perceive and respond to differences in photoperiod in the absence of functional CO1 and CO2 genes. Similarly, CO1 was able to accelerate heading time in response to LD in the absence of a functional PPD1. Taken together, these results indicate that PPD1 and CO1 are able to respond to photoperiod in the absence of each other, and that interactions between these two photoperiod pathways at the transcriptional and protein levels are important to fine-tune the flowering response in wheat.


Assuntos
Epistasia Genética/genética , Fotoperíodo , Proteínas de Plantas/genética , Triticum/genética , Alelos , Arabidopsis , Relógios Circadianos/genética , Ritmo Circadiano/genética , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/genética , Genótipo , Fatores de Transcrição/genética , Triticum/crescimento & desenvolvimento
15.
Environ Entomol ; 49(4): 912-917, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32607583

RESUMO

Diapause induction in multivoltine insects is an ecophysiological event that is generally triggered by seasonal cues such as photoperiod and temperature. The rice leaf bug, Trigonotylus caelestialium (Kirkaldy), feeds on various Poaceae grasses and produces several generations a year. Previous studies have shown that adults produce diapause and nondiapause eggs under short-day and long-day conditions, respectively. However, there is a distinct mid-summer peak in diapause incidence before an autumnal increase in diapause incidence in the field, which cannot be explained by the laboratory results. The present study was performed to examine the environmental factors affecting the diapause incidence in mid-summer and the adaptive significance of this phenomenon. Seasonal trends in diapause incidence differed significantly among three sites located 150-400 m apart from each other and with different host plants. The suitability of host plants differs depending on species and seasonally. Therefore, the microhabitat difference in diapause trend is believed to be due to the difference in host plants. When field-collected female adults laying diapause eggs in late June were fed a seasonally deteriorating host (the orange foxtail, Alopecurus aequalis Sobol. [Poales: Poaceae]), they kept laying diapause eggs, whereas when fed a suitable host (the wheat, Triticum aestivum L. [Poales: Poaceae]) for 5 d, they changed oviposition mode to lay nondiapause eggs. These results indicate that host-plant suitability affects the oviposition mode of T. caelestialium. Diapause-egg oviposition in mid-summer in T. caelestialium has adaptive significance as a bet-hedging strategy against unpredictable dietary conditions.


Assuntos
Diapausa de Inseto , Diapausa , Animais , Feminino , Incidência , Óvulo , Fotoperíodo , Estações do Ano
16.
PLoS One ; 15(7): e0235397, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32628713

RESUMO

Appropriate flowering and maturity time are important for soybean production. Four maturity genes E1, E2, E3 and E4 have been molecularly identified and found to play major roles in the control of flowering and maturity of soybean. Here, to further investigate the effect of different allele combinations of E1-E4, we performed Kompetitive Allele Specific PCR (KASP) assays based on single nucleotide polymorphisms (SNPs) at these four E loci, and genotyped E1-E4 genes across 308 Chinese cultivars with a wide range of maturity groups. In total, twenty-one allele combinations for E1-E4 genes were identified across these Chinese cultivars. Various combinations of mutations at four E loci gave rise to the diversity of flowering and maturity time, which were associated with the adaptation of soybean cultivars to diverse geographic regions and farming systems. In particular, the cultivars with mutations at all four E loci reached flowering and maturity very early, and adapted to high-latitude cold regions. The allele combinations e1-as/e2-ns/e3-tr/E4, E1/e2-ns/E3/E4 and E1/E2/E3/E4 played important roles in the Northeast China, Huang-Huai-Hai (HHH) Rivers Valley and South China regions, respectively. Notably, E1 and E2, especially E2, affected flowering and maturity time of soybean significantly. Our study will be beneficial for germplasm evaluation, cultivar improvement and regionalization of cultivation in soybean production.


Assuntos
Adaptação Fisiológica/genética , Regulação da Expressão Gênica de Plantas , Genes Controladores do Desenvolvimento , Locos de Características Quantitativas , Soja/fisiologia , Alelos , China , Produção Agrícola , Fazendas , Flores/crescimento & desenvolvimento , Genes de Plantas , Variação Genética , Genótipo , Geografia , Fotoperíodo , Fatores de Tempo
18.
Proc Natl Acad Sci U S A ; 117(26): 15293-15304, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32541062

RESUMO

Organisms possess photoperiodic timing mechanisms to detect variations in day length and temperature as the seasons progress. The nature of the molecular mechanisms interpreting and signaling these environmental changes to elicit downstream neuroendocrine and physiological responses are just starting to emerge. Here, we demonstrate that, in Drosophila melanogaster, EYES ABSENT (EYA) acts as a seasonal sensor by interpreting photoperiodic and temperature changes to trigger appropriate physiological responses. We observed that tissue-specific genetic manipulation of eya expression is sufficient to disrupt the ability of flies to sense seasonal cues, thereby altering the extent of female reproductive dormancy. Specifically, we observed that EYA proteins, which peak at night in short photoperiod and accumulate at higher levels in the cold, promote reproductive dormancy in female D. melanogaster Furthermore, we provide evidence indicating that the role of EYA in photoperiodism and temperature sensing is aided by the stabilizing action of the light-sensitive circadian clock protein TIMELESS (TIM). We postulate that increased stability and level of TIM at night under short photoperiod together with the production of cold-induced and light-insensitive TIM isoforms facilitate EYA accumulation in winter conditions. This is supported by our observations that tim null mutants exhibit reduced incidence of reproductive dormancy in simulated winter conditions, while flies overexpressing tim show an increased incidence of reproductive dormancy even in long photoperiod.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Proteínas do Olho/metabolismo , Fotoperíodo , Estações do Ano , Temperatura , Animais , Proteínas de Drosophila/genética , Proteínas do Olho/genética , Regulação da Expressão Gênica/fisiologia , Reprodução
19.
PLoS Genet ; 16(6): e1008814, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32555650

RESUMO

The circadian clocks in chlorophyte algae have been studied in two model organisms, Chlamydomonas reinhardtii and Ostreococcus tauri. These studies revealed that the chlorophyte clocks include some genes that are homologous to those of the angiosperm circadian clock. However, the genetic network architectures of the chlorophyte clocks are largely unknown, especially in C. reinhardtii. In this study, using C. reinhardtii as a model, we characterized RHYTHM OF CHLOROPLAST (ROC) 75, a clock gene encoding a putative GARP DNA-binding transcription factor similar to the clock proteins LUX ARRHYTHMO (LUX, also called PHYTOCLOCK 1 [PCL1]) and BROTHER OF LUX ARRHYTHMO (BOA, also called NOX) of the angiosperm Arabidopsis thaliana. We observed that ROC75 is a day/subjective day-phase-expressed nuclear-localized protein that associates with some night-phased clock genes and represses their expression. This repression may be essential for the gating of reaccumulation of the other clock-related GARP protein, ROC15, after its light-dependent degradation. The restoration of ROC75 function in an arrhythmic roc75 mutant under constant darkness leads to the resumption of circadian oscillation from the subjective dawn, suggesting that the ROC75 restoration acts as a morning cue for the C. reinhardtii clock. Our study reveals a part of the genetic network of C. reinhardtii clock that could be considerably different from that of A. thaliana.


Assuntos
Chlamydomonas reinhardtii/fisiologia , Relógios Circadianos/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/fisiologia , Fatores de Transcrição/fisiologia , Cloroplastos/fisiologia , Ritmo Circadiano/genética , Redes Reguladoras de Genes/fisiologia , Mutação , Fotoperíodo , Plantas Geneticamente Modificadas
20.
PLoS One ; 15(6): e0234439, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530967

RESUMO

Disturbance of circadian rhythms underlies various metabolic diseases. Constant light exposure (LL) is known to disrupt both central and peripheral circadian rhythms. Here, we attempted to determine whether the effects of LL are different between various peripheral tissues and whether time-restricted feeding restores the circadian rhythms especially in white adipose tissue (WAT). Six-week-old mice were subjected to three feeding regimes: ad libitum feeding under light/dark phase (LD), ad libitum feeding under LL cycle, and restricted feeding at night-time under LL cycle with a normal chow. After 3 weeks, we compared body weight, food intake, plasma levels of lipids and glucose, and the expression patterns of the clock genes and the genes involved in lipid metabolism in the liver and WAT. The mice kept under LL with or without time-restricted feeding were 5.2% heavier (p<0.001, n = 16) than the mice kept under LD even though the food intakes of the two groups were the same. Food intake occurred mostly in the dark phase. LL disrupted this pattern, causing disruptions in circadian rhythms of plasma levels of triglycerides (TG) and glucose. Time-restricted feeding partially restored the rhythms. LL eliminated the circadian rhythms of the expression of the clock genes as well as most of the genes involved in lipid metabolism in both liver and WAT. More notably, LL markedly decreased not only the amplitude but also the average levels of the expression of the genes in the liver, but not in the WAT, suggesting that transcription in the liver is sensitive to constant light exposure. Time-restricted feeding restored the circadian rhythms of most of the genes to various degrees in both liver and WAT. In conclusion, LL disrupted the peripheral circadian rhythms more severely in liver than in WAT. Time-restricted feeding restored the circadian rhythms in both tissues.


Assuntos
Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Ritmo Circadiano/fisiologia , Jejum/fisiologia , Luz/efeitos adversos , Metabolismo dos Lipídeos/fisiologia , Tecido Adiposo Branco/metabolismo , Animais , Ritmo Circadiano/efeitos da radiação , Regulação da Expressão Gênica/efeitos da radiação , Metabolismo dos Lipídeos/efeitos da radiação , Fígado/metabolismo , Masculino , Camundongos , Modelos Animais , Fotoperíodo
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