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Results for “Nocturnal adaptation”

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PubMed2026

Identification and characterization of G protein-coupled receptors in the nocturnal halictid bee Megalopta genalis.

G protein-coupled receptors (GPCRs) are one of the largest families of membrane proteins in insects, regulating vision, neural signal transduction, and various physiological behaviors. Megalopta genalis exhibits a unique facultatively eusocial lifestyle and possesses adaptations for nocturnal activity; however, its GPCR family has not yet been systematically characterized. In this study, we performed genome-wide identification, phylogenetic analysis, and expression profiling of GPCRs in M. genalis by integrating genomic annotation and transcriptomic analysis. The results showed that a total of 99 GPCRs were identified in the genome of M. genalis, which were classified into four major families. Here, we show that M. genalis has undergone lineage-specific GPCR repertoire remodeling, marked by the expansion of novel orphan receptors and the systematic loss of multiple receptor subtypes, such as the neuropeptide receptors MIP-R and NPFR. Moreover, opsins have formed a diverse array of combinations and non-GPCR odorant receptors have undergone significant expansion via tandem duplication. Together, these features may represent part of the molecular repertoire associated with the adaptation of M. genalis to a nocturnal lifestyle. Furthermore, transcriptomic analysis revealed distinct spatiotemporal expression divergence within each of the Mth/Mthl and Fz GPCR families, suggesting functional specialization across development and adult tissues. This study provides the first systematic identification and initial functional characterization of GPCRs in M. genalis, revealing an evolutionary pattern characterized by the coexistence of contraction and expansion within the GPCR family. These findings lay a foundation for further studies aimed at elucidating the roles of these GPCRs in regulating M. genalis physiology and behavior.

Animals↗

PubMed1978

[Biorhythm structure as one of the criteria of the body's capacity for physiologic adaptation].

In order to establish the criteria of the organism's ability for adaptation, we examined 16 healthy subjects, 10 of whom were able to very well adapt themselves to changes in environment, whereas 6 subjects could not do that well enough. In the background examinations (and for the well-adapting subjects in examinations made after meridian crossing in flight), the blood pressure, heart rate, and capillaroscopic picture were recorded during 3 days 5 times a day. Apart from that, the biorhythmic structure of the natural nocturnal sleep EEG was analysed. The data obtained showed that the well-adapting subjects had these characteristics of the biorhythms structure: relatively higher mean values of the parameters under study, a major dispersion of these values over different hours of the day and night, and clear temporal structure of the 24-hr curve as expressed by occurrence of the maximal and the minimal values of the functions at the same hours.

Adaptation, Physiological↗

PubMed1979

Chromosomal differentiation and adaptation to human environments in the Anopheles gambiae complex.

Speciation in the Anopheles gambiae complex is reviewed and discussed with emphasis on the patterns of chromosomal differentiation, particularly at the intraspecific level. The significance of inversion polymorphism in gambiae and arabiensis (the two species of greatest medical importance) is evaluated with reference to recent field investigations carried out in Nigeria. In both sibling species some of the inversions show clinical geographical changes in frequencies, with evident correlations with climatic conditions and vegetation zones. Microgeographical variations in species distribution and in intraspecific inversion frequencies are also present, which appear mostly related to man-made environmental contrasts. Parallel indoor-/outdoor collections of samples from polymorphic populations of arabiensis and gambiae show that adult mosquitoes carrying certain inversion karyotypes do not distribute at random in relation to the human environment, being significantly more frequent in outdoor than in indoor samples, or vice-versa. Optimal habitat choice appears to be involved in such variations of indoor resting behaviour, since the chromosomal types carried by less endophilic individuals are those more adapted to humid climates, i.e. those which tend to avoid the higher nocturnal saturation deficit of the indoor environment. This phenomenon, producing non-uniform exposure of the vector population to residual insecticides sprayed in houses, might explain the mediocrity of the results of malaria control projects based on house-spraying against endophilic vectors in the African savannas.

Animals↗

PubMed2025

Genetic analysis of Schistosoma mansoni in a low-transmission area in Brazil suggests population sharing between wild-hosts and humans and geographical isolation.

BACKGROUND: The fluke Schistosoma mansoni is the causative agent of intestinal schistosomiasis, a neglected tropical disease, and remains prevalent in certain regions of Brazil. In the municipality of Sumidouro, state of Rio de Janeiro, Brazil, a low-endemic area for S. mansoni, water rats (Nectomys squamipes) are naturally infected by this trematode. The S. mansoni populations infecting humans and water-rats in Sumidouro exhibit distinct patterns of cercarial emergence (chronotypes) and phenotypic differences between hosts. Previous studies have shown that the adaptation of S. mansoni populations to human hosts (diurnal chronotype) and water rats (nocturnal chronotype) could result in prezygotic isolation. To test this hypothesis, we employed the mitochondrial cytochrome c oxidase subunit 1 gene (MT-CO1) and microsatellite loci as genetic markers. PRINCIPAL FINDINGS: We assessed the population structure between the definitive host species and geographically distant isolates collected from two endemic localities (Pamparrão-PAM and Encanto-Soledade-ENC-SOL) in Sumidouro. Additionally, we evaluated the phylogenetic relationships between S. mansoni from Sumidouro and those from other countries. Five haplotypes of the MT-CO1 gene were identified, with haplotypes 3 and 4 exclusive to ENC-SOL, and haplotypes 1, 2, and 3 were shared between humans and water rats. Haplotype 1 was also shared with other Brazilian localities, South American countries and a single locality in West Africa. The remaining haplotypes were exclusive to Sumidouro, indicating local genetic diversity. Population structure analysis revealed no genetic differentiation associated with host species but rather geographical structuring, probably due to the sedentary habits of rodents and the limited movement of humans between localities. This finding indicates that S. mansoni populations with different chronotypes are not genetically isolated and that significant gene flow occurs between them. CONCLUSIONS: In conclusion, our findings confirm that wild rodents contribute to the maintenance of the S. mansoni life cycle in Sumidouro and can serve as indicators of local transmission hotspots.

Animals↗

PubMed1975

[Electroretinogram in the nocturnal Prosimian Perodicticus potto].

There is histological evidence for the presence of cones in potto's retina: about 1 cone for 300 rods. The ERG of the dark adapted animal resembles that of the night monkey. In the potto's retina some red sensitive elements respond to wavelenghts beyond those which affect visual purple. The ERG evoked by these long wavelenghts differs from that produced by white light, suggesting a duplex character of the retina. These red sensitive receptors dark adapt faster than the others. However their fusion frequency is low, if compared with that in other species with a duplex retina. Nevertheless in potto the critical fusion frequency is higher for red light than for blue light.

Animals↗

PubMed1975

Effects of a new butyrophenone derivate (Buronil) on nocturnal sleep in normal man.

Nocturnal sleep was studied in eight young normal volunteers (3 female and 5 male students) with polygraphic technique during 2 periods of 10 night each. After 2 adaptation and 2 baseline nights with placebo, they were given methylperone (Buronil) 10 or 50 mg per night during three nights and then again placebo for three withdrawal nights. The study was made double blind. The scoring of the records was done according to the manual by Rechtschaffen and Kales (1968). No changes of sleep stages were seen during the drug periods. The lower dose gave an increase of sleep latency but a decrease of number of awakenings during the night. An increase of REM-periods was shown after 50 mg and also a decrease of REM-latency and REM-density. The only significant change during withdrawal periods was a decrease of REM-sleep after methylperone 50 mg, so there was no "barbiturate type" of withdrawal. The change was also different from that of chloropromazine, which has no clear rebound effect.

Adult↗

PubMed1979

Pulsatile subcutaneous nocturnal administration of GnRH by portable infusion pump in hypogonadotropic hypogonadism: initiation of gonadotropin responsiveness.

GnRH was administered subcutaneously in hourly pulses for 10 consecutive nights to two immature males with Kallmann's Syndrome using a portable, battery-operated infusion pump adapted for home use. Pulsatile GnRH produced a progressive increase in urinary gonadotropin excretion, a significant increase in mean basal plasma FSH, pulsatile LH release, and an increased LH response to a standard 3 hour GnRH infusion test. One subject developed a striking increment in plasma testosterone in response to GnRH pulses, as well as a biphasic LH response to the 3 hour infusion.

Adolescent↗

PubMed2026

Neurocorrelates of nocturnal enuresis in pre-adolescent children.

INTRODUCTION: Nocturnal enuresis (NE) is a common neurodevelopmental condition, yet its underlying neural mechanisms remain unclear. This study leverages the large-scale Adolescent Brain Cognitive Development (ABCD) dataset to identify structural and functional brain correlates associated with active symptoms and the resolution of bedwetting. METHODS: Using cross-sectional data from 3472 participants aged 9-10 years, children were categorized into three groups: active nocturnal enuresis (ANE, n = 225), history of nocturnal enuresis (HNE, n = 1171), and healthy control groups (CG, n = 2076). Multimodal neuroimaging protocol evaluated macrostructural properties via structural MRI (sMRI), microstructural white matter integrity via diffusion MRI (dMRI), and functional connectivity via resting-state fMRI (fMRI). Group differences were evaluated using linear models within an ANCOVA framework, adjusting for intracranial volume and handedness with False Discovery Rate (FDR) correction. RESULTS: Compared to controls, the ANE group exhibited a significant volume deficit in the right caudate, decreased sulcal depth in the left insula, and lower internal correlation within the Cingulo-Opercular Network (CON). Conversely, the dry HNE group demonstrated significant structural adaptations, including bilaterally larger putamen volumes and increased right caudate volume compared to the ANE group. The HNE group also showed increased microstructural density (decreased mean diffusivity) in the bilateral hippocampus and an increased cortical surface area in the left insula. Both NE groups demonstrated persistently reduced functional coupling within the CON. CONCLUSIONS: Nocturnal enuresis appears to be associated with a potential complex central signaling deficits. Reduced internal correlation within the CON across both active and former bedwetters indicates a potential for impairment in processing internal homeostatic bladder signals during sleep.

Humans↗

PubMedDate not supplied

Circadian patterns of growth hormone and cortisol secretions in narcoleptic patients.

Narcolepsy, a disorder which is clinically characterized by recurring episodes of sleep during the day, frequently associated with nocturnal disrupted sleep and polygraphically by sleep onset REM periods, has been studied in regard to the relationships between GH, cortisol secretion and sleep. Ten narcoleptics were polygraphically recorded during 24 h after one night's adaptation. Blood samples were taken every 20 min for GH and cortisol immuno-assays. Three narcoleptics were recorded twice 2 months later and 2 normal subjects served as controls. The following results were obtained: GH secretory pattern was different in narcoleptics and controls; two groups were identified: the first one showed a very low basal GH secretion with rare and small secretory peaks not clearly linked with sleep. One subject of this group recorded twice showed a similar pattern. The second group exhibited a higher basal secretion with many peaks without any well-defined relationship to sleep stages. The pattern was again consistent in two recordings of 2 subjects in this group. Furthermore GH secretion rose significantly (p less than 0.01) between 2100 and 0000 with no apparent relationship to sleep stages. The cortisol secretory pattern showed a significant rise (p less than 0.01) between 0400 and 1000 and was not different in narcoleptics and controls. In narcolepsy the monophasic sleep-wakefulness cycle is disrupted. The GH secretion pattern is modified whereas the circadian pattern of cortisol secretion is normal and independent of the sleep-wakefulness cycle of the narcoleptic patient.

Adult↗

PubMed1979

Effects of feeding a single daily meal and of changes in lighting schedule on the circadian rhythms of oxidoreductases in the rat gastric mucosa.

The present paper investigated the effect of restricted feeding (11.00 to 13.00 h) by a single daily meal upon the activity of various oxidoreductases of the rat gastric mucosa (SDH, alpha-GPDH, LDH, NADHTR), which at ad libitum feeding under normal lighting conditions with a dark night were shown to have distinct circadian activity variations related to the rat's nocturnal food intake preference (Zaviacic and Brozman 1978a). 1st part of the animals received food in 2-h-period by natural daylight (natural lighting conditions), the 2nd part at the same period of time but in the dark (lighting conditions reversed to natural). Checking the consumption of food, we found the animals to become adapted to the new time of food intake beginning with the 6th experimental day. The circadian rhythm of enzymes was examined on days 69, 83, 97, and 104 of limited feeding under the defined lighting schedule, at 06.00 h, 12.00 h, 18.00 h, and 24.00 h in groups of 5 animals. Synchronization of the highest dehydrogenases activities (particularly of SDH) with the time of restricted feeding was seen to develop in the gastric mucosa of the rat. The synchronization effect was more pronounced in the animals which received their food in the dark (and here even more in male than in female). The effect of light during food intake was found to be rather interfering with the development of synchronization of dehydrogenase activities with the time of food intake, and the influence was again more marked in male than in female. The time of food intake was at the feeding schedule restricted to daytime intake the main synchronizer for the circadian rhythm of oxidoreductases of the gastric mucosa of the rat, with the highest daily activities recorded around the feeding time and the lowest activities at night, which is the direct opposite of the circadian rhythm of the same enzymes determined in rats fed ad libitum under normal lighting conditions with a dark night.

Animals↗

PubMed2026

GIRK Channels Regulate Circadian Rhythms of Excitability in Prokineticin 2 Neurons of the Suprachiasmatic Nucleus and Modulate Behavioral Circadian Rhythms.

The suprachiasmatic nucleus (SCN), the central circadian clock in mammals, generates robust yet adaptable circadian rhythms through electrically mediated coordination among heterogeneous peptidergic neuronal populations with presumed cell type-specific roles. Previous studies have proposed that circadian changes in membrane excitability of individual SCN neurons arise from time-of-day-dependent shifts in the relative balance of subthreshold Na+ and K+ conductances. Although multiple channels have been implicated in these processes, how nocturnally dominant K+ conductances are implemented in a cell type-specific manner remains poorly understood. Prokineticin 2 (Prok2) has been identified as a SCN signaling peptide essential for behavioral circadian regulation; however, the electrophysiological properties of Prok2-expressing neurons and the mechanisms underlying their diurnal rhythmicity remain largely unexplored. Here, using electrophysiological approaches in mice of either sex, we show that Prok2 neurons exhibit diurnal variations in electrical properties, with higher excitability during the day and reduced excitability at night, and that G-protein-coupled inwardly rectifying potassium (GIRK) channel-mediated basal current contributes to nighttime hyperpolarization. Immunofluorescence and single-cell RT-PCR analyses revealed that GIRK1 and GIRK3 are the predominant GIRK subunits expressed in Prok2 neurons. Moreover, Prok2 neuron-specific deletion of GIRK3 using in vivo genome editing resulted in significant nocturnal depolarization and induced abnormalities in behavioral rhythms, including delayed activity onset and circadian period lengthening, with altered SCN network activity. Together, these findings suggest that tonic, G-protein-dependent regulation of GIRK channels provides a night-specific inhibitory mechanism that contributes to intrinsic diurnal neuronal excitability in Prok2 neurons and supports the regulation of behavioral circadian rhythms.

Animals↗

PubMed1976

A duplex retina and the electroretinogram in the nocturnal Perodicticus potto.

The presence of cones in potto's retina has been proved beyond doubt although they are very restricted in number (1 cone for 300 rods). Morphologically, speaking there is no point in calling these cones "rudimentary" except for their slender outer segment. There are red sensitive elements in that retina at wavelengths beyond the spectral sensitivity of visual purple and it is tempting to assume that these elements are cones. The ERG evoked from these elements by red light differs from that in response to white and blue light. They dark-adapt faster than the receptors sensitive to blue and white flashes. However in some of their properties, for example fusion frequency, these cones behave like rods in other species. As these few cones seem to activate the bipolar cells nearly as effectively as the numerous rods, it is suggested that these cones may be responsible for day vision in the potto.

Animals↗

PubMed1977

Polygraphic sleep recordings before and after the administration of flunitrazepam.

By means of polygraphic sleep recordings (EEG, EOG, EMG, ECG, EDG, Respirogram, Positogram), neurologic-psychologic investigation and questionnaires on subjective feeling, ten patients aged from 22 to 40 years (mean: 29 years), who suffered from irregular disturbances in falling asleep and in sleeping continuously, were examined over a period of ten consecutives nights. The first investigation night was reserved for adaptation of the patients and could therefore not be evaluated. On the following three evenings placebo (Placebo I) was given, then 2 mg of flunitrazepam for the ensuing three nights and placebo again (Placebo II) for the last three nights. Thus, 90 investigation nights could be evaluated. 1. Latency times until the patients fell asleep and up to the first deep sleep were reduced significantly by the active preparation. Latency times up to the first REM-phase were prolonged. 2. The frequency of nocturnal awakenings was lessened significantly. Thus, disturbances in sleeping continuously disappeared for the duration of the treatment. Duration of wakefulness after having woken during the night decreased considerably. 3. Duration of wakefulness during the total night was reduced considerably, deeper sleep stages, such as D (stage III) and E(stage IV) were prolonged. 4. Duration of the REM-phases was reduced slightly. This reduction was not significant according to the t-test. 5. According to these results, the preparation showed a clear effect. A placebo-effect can be excluded, since the improvements mentioned were not found when placebo was given before administration of the medication and afterwards (Placebo I and II). 6. When comparing our results to those of other authors, who described the effects of various preparations, we found that the substance flunitrazepam showed different effects.

Adult↗

PubMed2025

Unraveling the molecular choreography of C3 to CAM transition in Mesembryanthemum crystallinum using phosphoproteomics.

Climate change and population growth threaten global freshwater resources and food security. Crassulacean acid metabolism (CAM) is a specialized photosynthetic adaptation that exhibits superior water use efficiency (WUE) compared to C3 and C4 photosynthesis. Mesembryanthemum crystallinum (common ice plant) is capable of shifting from C3 to CAM, making it a key model for investigating photosynthesis plasticity and its potential to enhance crop stress resilience. To date, the molecular mechanisms underlying this high-WUE photosynthetic transition remain largely unknown. Using mass spectrometry-based proteomics and phosphoproteomics, we quantified 4233 phosphopeptides containing 4758 phosphorylation sites, including the well-characterized Serine 11 of phosphoenolpyruvate carboxylase 1 (PEPC1). It is a critical phosphorylation site facilitating nocturnal CO2 fixation during CAM. Our analysis revealed many phosphorylation sites that exhibited similar diel patterns as the PEPC1 pS11, and they may be part of the regulatory network involved in CAM induction. Glycolysis/gluconeogenesis and carbon storage/breakdown modules exhibited extensive phosphorylation regulation, and vesicle trafficking could play a role in nocturnal carbon fixation. Furthermore, glycine-rich RNA-binding protein 7 (GRP7) in association with cold shock protein 1 (CSP1) emerged as a potential transcriptional switch for nocturnal stomatal opening. On the other hand, ABI5-binding protein 1 (AFP1) and oxidative stress 3 (OXS3)-activated ABA signaling, along with high CO2 signaling and suppressed blue light signaling, may contribute to diurnal stomatal closure. These findings shed light on the protein phosphorylation changes and provide valuable targets for functional characterization of their roles in CAM induction.

Mesembryanthemum↗

PubMed1976

Sleep analysis during drug-free weekends in chronic schizophrenic patients.

The authors made a polygraphic registration of the night sleep in a sample of 14 chronic schizophrenic patients who for several months (mean 8 months) have been on a stable, relatively low maintenance dosage of neuroleptics administered according to the drug-free weekend schedule (two consecutive drug-free days at the weekend). During this treatment none of them showed a relapse or deterioration (BPRS, CGI, and NOSIE rating scales were applied periodically). Their only complaint was of sleep deterioration during the drugfree weekend nights, especially during the second night. The polygraphic night-sleep pattern of each patient was studied during two consecutive weeks. No difference was found between the adaptation night on medication and the consecutive night on medication during the first week, and between the adaptation and readaptation nights on medication during two consecutive weeks. There was no difference in any sleep parameters between the nights on medication and the first drug-free nights. There was a signifcant difference in the total sleep time between the nights on medications and the second drug-free nights. No difference was found in any other sleep parameters in nights analysed as a blocks and in the distribution of NREM and REM stages in the first vs. the second half of the night when B3 was compared with A2. The practical implication is, that to avoid any change in nocturnal behavior it is preferable to withdraw the medication on two nonconsecutive days in the week. The evaluation of both daily and nocturnal behavior seems to be a useful tool in evaluating the first sign of the drug-withdrawal syndrome.

Adult↗

PubMed1979

Radar-based studies of the migratory flight of grasshoppers in the middle Niger area of Mali.

Some grasshopper species are pests of subsistence agriculture in the Sahelian zone of West Africa. Formulation of effective control strategies against these pests requires some knowledge of their migratory ability. In this paper a study is described in which radar was used to observe aspects of the nocturnal migratory behaviour of grasshoppers in the middle Niger delta. Mass take-off at dusk, layering and common orientation were regularly observed. Layering appeared to be related to air temperature. Mean orientation was often downwind but at other times crosswind headings occurred which added to the southerly component of the insects' displacement. Probable source areas of insects overflying the radar were identified by calculations of the insects' back-trajectories.

Adaptation, Physiological↗

PubMed2026

Insights Into the Structural Features, Codon Usage Patterns, and Phylogenetic Analysis in Neoniphon argenteus (Teleostei: Holocentriformes) Based on Complete Mitochondrial Genome.

Neoniphon argenteus, a widely distributed nocturnal coral reef fish in the family Holocentridae, plays an important role in maintaining coral reef ecosystem health, yet its phylogenetic position remains poorly resolved. To bridge this gap, we sequenced and analyzed the complete mitochondrial genome of a specimen from the South China Sea to characterize its structural features, codon usage patterns, and phylogenetic relationships. The 16,569 bp mitogenome (GenBank: PP190474.1) encodes 13 protein-coding genes (PCGs), 22 tRNAs, two rRNAs, and two non-coding regions, exhibiting a distinct A + T bias. All tRNAs fold into typical cloverleaf secondary structures except tRNA-Ser (AGN), which lacks the dihydrouridine (DHU) arm. The control region contains palindromic motifs (TACAT/ATGTA) capable of forming hairpin structures and five conserved sequence blocks, whereas the OL region harbors a conserved 5'-GCCGG-3' motif. RSCU analysis revealed 31 frequently used codons (RSCU > 1) with a pronounced preference for A/C-ending codons. The ΔRSCU method identified 10 candidate optimal codons (GCA, CAA, GAA, GGA, AUU, CUA, CCA, CGA, ACA, and GUC). Selection pressure analysis using EasyCodeML and site-specific models indicated that all PCGs are predominantly under purifying selection, with no significant evidence of pervasive positive selection. ND6 exhibited elevated pairwise Ka/Ks ratios (mean = 1.209 ± 0.047), consistent with reduced selective constraint rather than adaptive evolution. Phylogenetic analysis of 19 Holocentriformes species using maximum likelihood and Bayesian inference with partitioned models based on 13 PCGs and two rRNA genes (12S and 16S) assigned all taxa to two well-supported subfamilies (Holocentrinae and Myripristinae). Within Holocentrinae, Neoniphon species form a monophyletic clade nested within a paraphyletic Sargocentron, suggesting that the genus Sargocentron as currently defined is not monophyletic. This study provides useful baseline molecular data for further exploration of the evolutionary history of N. argenteus and other members of Holocentriformes.

Holocentridae↗