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1.
Extensive research has been carried out to understand how circadian clocks regulate various physiological processes in organisms.
The discovery of clock genes and the molecular clockwork has helped researchers to understand the possible role of these genes
in regulating various metabolic processes. In Drosophila melanogaster, many studies have shown that the basic architecture of circadian clocks is multi-oscillatory. In nature, different neuronal
subgroups in the brain of D. melanogaster have been demonstrated to control different circadian behavioural rhythms or different aspects of the same circadian rhythm.
Among the circadian phenomena that have been studied so far in Drosophila, the egg-laying rhythm is unique, and relatively less explored. Unlike most other circadian rhythms, the egg-laying rhythm
is rhythmic under constant light conditions, and the endogenous or free-running period of the rhythm is greater than those
of most other rhythms. Although the clock genes and neurons required for the persistence of adult emergence and activity/rest
rhythms have been studied extensively, those underlying the circadian egg-laying rhythm still remain largely unknown. In this
review, we discuss our current understanding of the circadian egg-laying rhythm in D. melanogaster, and the possible molecular and physiological mechanisms that control the rhythmic output of the egg-laying process. 相似文献
2.
E. V. Bogomolova N. V. Adon’eva N. V. Faddeeva N. E. Gruntenko I. Yu. Raushenbakh 《Russian Journal of Genetics》2011,47(4):489-491
Tissue-specific inhibition of the expression of the D2-like dopamine receptor gene (DD2R) in the corpus allatum (CA), which is a gland that synthesizes the juvenile hormone (JH), was tested for effect on alkaline
phosphatase (ALP) activity and the intensity of the ALP response to heat stress (stress reactivity) in female Drosophila melanogaster. ALP activity and ALP stress reactivity in transgenic females with lower DD2R expression in the CA were higher than in control flies. A pharmacological elevation in JH increased ALP activity in females
of the control strains. DD2R was assumed to mediate the inhibitory effect of dopamine of JH synthesis in the CA of D. melanogaster. 相似文献
3.
David J. Ellis Bruce T. Firth Ingrid Belan 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(7):695-701
This study examined whether the daily rhythms of locomotor activity and behavioural thermoregulation that have previously
been observed in Australian sleepy lizards (Tiliqua rugosa) under field conditions are true circadian rhythms that persist in constant darkness (DD) and whether these rhythms show
similar characteristics. Lizards held on laboratory thermal gradients in the Australian spring under the prevailing 12-hour
light : dark (LD) cycle for 14 days displayed robust daily rhythms of behavioural thermoregulation and locomotor activity.
In the 13-day period of DD that followed LD, most lizards exhibited free-running circadian rhythms of locomotor activity and
behavioural thermoregulation. The predominant activity pattern displayed in LD was unimodal and this was retained in DD. While
mean levels of skin temperature and locomotor activity were found to decrease from LD to DD, activity duration remained unchanged.
The present results demonstrate for the first time that this species’ daily rhythm of locomotor activity is an endogenous
circadian rhythm. Our results also demonstrate a close correlation between the circadian activity and thermoregulatory rhythms
in this species indicating that the two rhythms are controlled by the same master oscillator(s). Future examination of seasonal
aspects of these rhythms, may, however, cause this hypothesis to be modified. 相似文献
4.
Rauschenbach IY Adonyeva NV Alekseev AA Chentsova NA Gruntenko NE 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2008,178(3):315-320
The effect of 20-hydroxyecdysone (20E) and the juvenile hormone (JH) on the activity of the arylalkylamine N-acetyltransferase (AANAT) was studied in young females of wild-type D. virilis and D. melanogaster. 20E feeding of the flies led to a decrease in AANAT activity in both species when dopamine (DA) was used as substrate, but
did not affect the enzyme activity when octopamine (OA) was used as substrate. JH application increased AANAT activity with
DA as substrate in both species, but did not change it with OA as substrate. AANAT activity was also measured in young females
of a JH-deficient strain of D. melanogaster, apterous
56f
. A decrease in the enzyme activity was observed in the mutant females as compared to wild-type. Mechanisms of regulation
of DA level by gonadotropins in Drosophila are discussed. 相似文献
5.
Milena Damulewicz Agnieszka Loboda Alicja Jozkowicz Jozef Dulak Elzbieta Pyza 《Molecular neurobiology》2017,54(7):4953-4962
The Drosophila retina has an autonomous peripheral circadian clock in which the expression of the gene encoding heme oxygenase (HO) is under circadian control with the ho mRNA peaking at the beginning of the day and in the middle of the night. The function of HO in the retina is unknown, but we observed that it regulates the circadian clock and protects photoreceptors against DNA damage. The decline in HO level increases and decreases the expression of the canonical clock genes period (per) and Clock (Clk), respectively. The opposite result was observed after increasing HO expression. Among three products of HO activity—carbon monoxide (CO), ferrous ions, and biliverdin—the latter has no effect on per and Clk expressions, but CO exerts the same effect as the increase of ho expression. This suggests that HO action on the clock is mediated by CO, which may affect Clk expression during the day and the level of per expression. While ho expression is not stimulated by nitric oxide (NO), NO has the same effect on the clock as HO, increasing Clk expression and decreasing the expression of per. 相似文献
6.
Neurons have an enormous capacity to adapt to changing conditions through the regulation of gene expression, morphology, and
physiology. In the fruit fly Drosophila melanogaster, this plasticity includes recurrent changes taking place within intervals of a few hours during the day. The rhythmic alterations
in the morphology of neurons described so far include changes in axonal diameter, branching complexity, synapse numbers, and
the number of synaptic vesicles. The cycles of these changes have larger amplitude when the fly is exposed to light, but they
persist in constant darkness and require the expression of the clock genes period and timeless, leading to the concept of circadian plasticity. The molecular mechanisms driving these cycles appear to require the expression
of these genes either inside the neurons themselves or in other peripheral pacemaker cells. Loss-of-function mutations in
period and timeless not only abolish the morphological rhythms, but also often cause abnormal axonal branching suggesting that circadian plasticity
is relevant for the maintenance of normal morphology. Research into whether (1) circadian plasticity is a common feature of
neurons in all animals and (2) our own neurons change shape between day and night will be of interest. 相似文献
7.
Ji-Gweon Park Yong-Ju Park Nozomi Sugama Se-Jae Kim Akihiro Takemura 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(4):403-411
As the first step in understanding the molecular oscillation of the circa rhythms in the golden rabbitfish Siganus guttatus—a reef fish with a definite lunar-related rhythmicity—we cloned and sequenced a Period gene (rfPer). The rfPer gene contained an open reading frame that encodes a protein consisting of 1,452 amino acids; this protein is highly homologous
to PER proteins of vertebrates including zebrafish. Phylogenetic analyses indicated that the rfPER protein is related to the
zebrafish PER1 and PER4. The expression of rfPer mRNA in the whole brain, retina, and liver under light/dark (LD) conditions increased at 06:00 h and decreased at 18:00 h,
suggesting that its robust circadian rhythm occurs in neural and peripheral tissues. When daily variation in the expression
in rfPer mRNA in the whole brain and cultured pineal gland were examined under LD conditions, similar expression patterns of the gene
were observed with an increase around dawn. Under constant light condition, the increased expression of rfPer mRNA in the whole brain disappeared around dawn. The present results demonstrate that rfPer is related to zPer4 and possibly zPer1. The present study is the first report on the Period gene from a marine fish. 相似文献
8.
9.
Alberto Ugolini Silvia Somigli Vittorio Pasquali Paolo Renzi 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(12):1259-1263
The sandhopper Talitrus saltator has an endogenous activity rhythm with a circadian periodicity. It is well known for its ability to compensate for the apparent
movement of the sun during its migrations along the sea–land axis of the beach. Both chronometric mechanisms are entrained
by the natural LD photoperiod. Using actographic recordings and tests of solar orientation of individuals kept under an LD
12:12 clock-shifted cycle, after 1–13 days of treatment, we demonstrate that the timing mechanism of activity rhythm and the
chronometric mechanism underlying the sun compass are the same. 相似文献
10.
Ishikawa R Aoki M Kurotani K Yokoi S Shinomura T Takano M Shimamoto K 《Molecular genetics and genomics : MGG》2011,285(6):461-470
11.
Numerous studies have investigated using oxalic acid (OA) to control Varroa mites in honey bee colonies. In contrast, techniques for treating package bees with OA have not been investigated. The goal
of this study was to develop a protocol for using OA to reduce mite infestation in package bees. We made 97 mini packages
of Varroa-infested adult bees. Each package contained 1,613 ± 18 bees and 92 ± 3 mites, and represented an experimental unit. We prepared
a 2.8% solution of OA by mixing 35 g OA with 1 l of sugar water (sugar:water = 1:1; w:w). Eight treatments were assigned to
the packages based on previous laboratory bioassays that characterized the acute contact toxicity of OA to mites and bees.
We administered the treatments by spraying the OA solution directly on the bees through the mesh screen cage using a pressurized
air brush and quantified mite and bee mortality over a 10-day period. Our results support applying an optimum volume of 3.0 ml
of a 2.8% OA solution per 1,000 bees to packages for effective mite control with minimal adult bee mortality. The outcome
of our research provides beekeepers and package bee shippers guidance for using OA to reduce mite populations in package bees. 相似文献
12.
To ensure that the initiation of flowering occurs at the correct time of year, plants need to integrate a diverse range of
external and internal signals. In Arabidopsis, the photoperiodic flowering pathway is controlled by a set of regulators that include CONSTANS (CO). In addition, Arabidopsis plants also have a family of genes with homologies to CO known as CO-LIKE (COL) about which relatively little is known. In this paper, we describe the regulation and interactions of a novel member of
the family, COL5. The expression of COL5 is under circadian and diurnal regulation, but COL5 itself does not appear to affect circadian rhythms. COL5, like CO, is regulated by GIGANTEA. Furthermore, COL5 is expressed in the vascular tissue. Using COL5 over-expressing lines we show that, under short days, constitutive expression of COL5 affects flowering time and the expression of the floral integrator genes, FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CO 1. Constitutive expression of COL5 partially suppresses the late flowering phenotype of the co-mutant plants. However, plants with loss of COL5 function do not show altered flowering. Taken together, our results suggest that COL5 has COL activity, but may either not
have a role in regulating flowering in wild-type plants or may act redundantly with other flowering regulators.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
A degradation experiment on dibenzo-p-dioxin (DD) and 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD) was carried out using basidiomycetous fungi belonging to the genera Coprinus, Coprinellus, and Coprinopsis. Some species showed a high rate of decrease in DD for the 2-week test period. Among them, Coprinellus disseminatus showed the highest ability to decrease the DD level, close to 100% by the end of 2 weeks. Further examination showed that
Coprinellus disseminatus and Coprinellus micaceus, belonging to the genus Coprinellus, were able to metabolize 2,7-DCDD to a monohydroxylated compound, probably mediated by the P450 system. The metabolism of
chlorinated DD by fungi capable of living in soil conditions is reported here for the first time. 相似文献
14.
Using a cDNA-array we identified expressed sequence tag 163B24T7 as rapidly up-regulated in Arabidopsis thaliana (L.) Heynh. after pathogen exposure. Detailed expression analysis revealed that the corresponding gene is up-regulated not only after exposure to avirulent Pseudomonas syringae pv. tomato but also to virulent strains. This up-regulation is dependent on functional salicylic acid defence-signalling pathways. Moreover, we found the gene was circadian-regulated, showing peaks of expression at the end of the day. Using plants overexpressing the clock component CCA1, we showed that the PCC1 gene is regulated by the inner clock of Arabidopsis. Accordingly, we named the gene PCC1, for pathogen and circadian controlled. PCC1 is a member of a novel family of six small polypeptides in Arabidopsis. A functional role for PCC1 in plant defence was demonstrated since plants overexpressing PCC1 are resistant against normally virulent oomycetes. Thus, PCC1 demonstrates a potential interrelationship between pathogen and circadian signalling pathways.Abbreviations
cfu
Colony-forming units
-
EST
Expressed sequence tag
-
Pst
Pseudomonas syringae pv. tomato
-
TAIR
The Arabidopsis information resource 相似文献
15.
Sugar-induced adventitious roots in<Emphasis Type="Italic"> Arabidopsis</Emphasis> seedlings 总被引:3,自引:0,他引:3
The effects of sugars on root growth and on development of adventitious roots were analyzed in Arabidopsis thaliana. Seeds were sown on agar plates containing 0.0–5.0% sugars and placed vertically in darkness (DD) or under long day (LD,
16 h:8 h) conditions, so that the seedlings were constantly attached to the agar medium. In the sucrose-supplemented medium,
seedlings showed sustained growth in both DD and LD. However, only dark-grown seedlings developed adventitious roots from
the elongated hypocotyl. The adventitious roots began to develop 5 days after imbibition and increased in number until day 11.
They could, however, be initiated at any position along the hypocotyl, near the cotyledon or the primary root. They were initiated
in the pericycle in the same manner as ordinary lateral roots. Sucrose, glucose and fructose greatly stimulated the induction
of adventitious roots, but mannose or sorbitol did not. Sucrose at concentrations of 0.5–2.0% was most effective in inducing
adventitious roots, although 5.0% sucrose suppressed induction. Direct contact of the hypocotyl with the sugar-supplemented
agar medium was indispensable for the induction of adventitious roots.
Electronic Publication 相似文献
16.
V. A. Zotov 《Entomological Review》2017,97(1):17-19
In the Karakum Desert (Turkmenistan) the beetles Trigonoscelis gigas are only active in the morning and evening while T. sublaevicollis are strictly nocturnal, regardless of the season and weather. The daily activity rhythm of T. gigas and T. sublaevicollis was studied in the laboratory according to the following pattern: 5 days under a light-darkness cycle of 15: 9 h (LD 15: 9), then 10 days in constant darkness (DD), and then 10 more days under alternating 1-h pulses of light and darkness (LD 1: 1). The temperature was 25°C in all the modes. At LD 15: 9, beetles of both species maintained a 24-h period and a natural pattern of the activity rhythm. In DD, the circadian rhythm ran with a period of 23.5 ± 0.3 h (n = 40) in T. gigas and 23.6 ± 0.4 h (n = 40) in T. sublaevicollis. At DD, the morning and evening activity peaks of T. gigas merged to form a rhythm with only one peak. Under LD 1: 1, both T. gigas and T. sublaevicollis recovered a 24-h period of the rhythm, while the rhythm of T. gigas regained the two-peak structure. Our research confirmed the assumption of Tshernyshev (1980) about the 24-h period of the free-running endogenous rhythm and the distorting effect of constant conditions on this rhythm. 相似文献
17.
ATP-binding cassette (ABC) transporters are widespread among organisms, and 56 genes encode ABC transporters in Drosophila
melanogaster (Meigen). Their functions are thought to be divergent. In this study, we examined whether there is a clock-related ABC transporter
by performing genome-wide screening using tissue-specific RNA interference. We obtained five candidates when we used tim(UAS)-gal4, which expresses in virtually all clock-related cells. Because their phenotypes were principally reproducible even when we
used pdf-gal4, which expresses in a subset of pacemaker neurons only, those transporters were presumed to function in pacemaker neurons.
Those five candidates can be categorized into two groups according to the phenotype of the knockdown flies. In one group,
CG9281 and CG15410 (E23), the circadian period of knockdown flies was altered. In the other group, CG5944, CG6052, and CG18633, some of the knockdown flies became arrhythmic whereas for others rhythmicity remained intact. Our results suggest that some
ABC transporters that have a significant function in the Drosophila circadian system. 相似文献
18.
Summary European and African subspecies of honeybees (Apis mellifera L.) utilize social encapsulation to contain the small hive beetle (Aethina tumida Murray), a honeybee colony scavenger. Using social encapsulation, African honeybees successfully limit beetle reproduction that can devastate host colonies. In sharp contrast, European honeybees often fail to contain beetles, possibly because their social encapsulation skills may be less developed than those of African honeybees. In this study, we quantify beetle and European honeybee behaviours associated with social encapsulation, describe colony and time (morning and evening) differences in these behaviours (to identify possible circadian rhythms), and detail intra-colonial, encapsulated beetle distributions. The data help explain the susceptibility of European honeybees to depredation by small hive beetles. There were significant colony differences in a number of social encapsulation behaviours (the number of beetle prisons and beetles per prison, and the proportion of prison guard bees biting at encapsulated beetles) suggesting that successful encapsulation of beetles by European bees varies between colonies. We also found evidence for the existence of circadian rhythms in small hive beetles, as they were more active in the evening rather than morning. In response to increased beetle activity during the evening, there was an increase in the number of prison guard bees during evening. Additionally, the bees successfully kept most (~93%) beetles out of the combs at all times, suggesting that social encapsulation by European honeybees is sufficient to control small populations of beetles (as seen in this study) but may ultimately fail if beetle populations are high.Received 20 January 2003; revised 21 April 2003; accepted 29 April 2003. 相似文献
19.
Lou P Xie Q Xu X Edwards CE Brock MT Weinig C McClung CR 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(3):397-409
The circadian clock serves to coordinate physiology and behavior with the diurnal cycles derived from the daily rotation of
the earth. In plants, circadian rhythms contribute to growth and yield and, hence, to both agricultural productivity and evolutionary
fitness. Arabidopsis thaliana has served as a tractable model species in which to dissect clock mechanism and function, but it now becomes important to
define the extent to which the Arabidopsis model can be extrapolated to other species, including crops. Accordingly, we have extended our studies to the close Arabidopsis relative and crop species, Brassica rapa. We have investigated natural variation in circadian function and flowering time among multiple B. rapa collections. There is wide variation in clock function, based on a robust rhythm in cotyledon movement, within a collection
of B. rapa accessions, wild populations and recombinant inbred lines (RILs) derived from a cross between parents from two distinct subspecies,
a rapid cycling Chinese cabbage (ssp. pekinensis) and a Yellow Sarson oilseed (ssp. trilocularis). We further analyzed the RILs to identify the quantitative trait loci (QTL) responsible for this natural variation in clock
period and temperature compensation, as well as for flowering time under different temperature and day length settings. Most
clock and flowering-time QTL mapped to overlapping chromosomal loci. We have exploited micro-synteny between the Arabidopsis and B. rapa genomes to identify candidate genes for these QTL. 相似文献
20.
Cane JH 《Oecologia》2011,167(1):107-116
Pollinators, even floral generalists (=polyleges), typically specialize during individual foraging bouts, infrequently switching
between floral hosts. Such transient floral constancy restricts pollen flow, and thereby gene flow, to conspecific flowers
in mixed plant communities. Where incipient flowering species meet, however, weak cross-fertility and often similar floral
traits can yield mixed reproductive outcomes among pollinator-dependent species. In these cases, floral constancy by polyleges
sometimes serves as an ethological mating barrier. More often, their foraging infidelities instead facilitate host introgression
and hybridization. Many other bee species are oligolectic (taxonomic specialists for pollen). Oligoleges could be more discriminating
connoisseurs than polyleges when foraging among their limited set of related floral hosts. If true, greater foraging constancy
might ensue, contributing to positive assortative mating and disruptive selection, thereby facilitating speciation among their
interfertile floral hosts. To test this Connoisseur Hypothesis, nesting females of two species of oligolectic Osmia bees were presented with randomized mixed arrays of flowers of two sympatric species of their pollen host, Balsamorhiza, a genus known for hybridization. In a closely spaced grid, the females of both species preferred the larger flowered B. macrophylla, evidence for discrimination. However, both species’ females showed no floral constancy whatsoever during their individual
foraging bouts, switching randomly between species proportional to their floral preference. In a wider spaced array in which
the bouquets reflected natural plant spacing, foraging oligolectic bees often transferred pollen surrogates (fluorescent powders)
both between conspecific flowers (geitonogamy and xenogamy) and between the two Balsamorhiza species. The Connoisseur Hypothesis was therefore rejected. Foraging infidelity by these oligolectic Osmia bees will contribute to introgression and hybridization where interfertile species of Balsamorhiza meet and flower together. A literature review reveals that other plant genera whose species hybridize also attract numerous
oligolectic bees, providing independent opportunities to test the generality of this conclusion. 相似文献