Seasonal Reproduction in Vertebrates: Melatonin Synthesis, Binding, and Functionality Using Tinbergen's Four Questions.
Ontology highlight
ABSTRACT:
SUBMITTER: viviD D
PROVIDER: S-EPMC6017951 | biostudies-literature | 2018 Mar
REPOSITORIES: biostudies-literature
Publications
Seasonal Reproduction in Vertebrates: Melatonin Synthesis, Binding, and Functionality Using Tinbergen's Four Questions.
viviD Dax D Bentley George E GE
Molecules (Basel, Switzerland) 20180313 3
One of the many functions of melatonin in vertebrates is seasonal reproductive timing. Longer nights in winter correspond to an extended duration of melatonin secretion. The purpose of this review is to discuss melatonin synthesis, receptor subtypes, and function in the context of seasonality across vertebrates. We conclude with Tinbergen's Four Questions to create a comparative framework for future melatonin research in the context of seasonal reproduction. ...[more]
Similar Datasets
Project description:Melatonin receptors (MTNRs) belonging to the G protein-coupled receptor family are considered to consist of three subtypes in vertebrates: MTNR1a, MTNR1b and MTNR1c. Additionally, MTNR1a-like genes have been identified in teleostean species as a fish-specific subtype of MTNR1a. However, similar molecules to this MTNR1a-like gene can be found in some reptiles upon searching the DNA database. We hypothesized that a vertebrate can essentially have four functional subtypes of MTNR as ohnologs. Thus, in the present study we examined the molecular phylogeny, expression patterns and pharmacological profile(s) using the teleost medaka (Oryzias latipes). The four conserved subtypes of MTNR (MTNR1a, MTNR1b, MTNR1c and MTNR1a-like) in vertebrates were classified based on synteny and phylogenetic analysis. The fourth MTNR, termed MTNR1a-like, could be classified as MTNR1d. It was observed by using RT-qPCR that expression patterns differed amongst these subtypes. Moreover, mtnr1a, mtnr1c and mtnr1a-like/mtnr1d expression was elevated during short days compared to long days in diencephalons. All the subtypes were activated by melatonin and transduced signals into the Gi pathway, to perform a cAMP-responsive reporter gene assay. It was shown that MTNR originally consisted of four subtypes: MTNR1a, MTNR1b, MTNR1c and MTNR1d. These subtypes were functional, at least in fish, although some organisms, including mammals, have lost one or two subtypes.
| S-EPMC6602942 | biostudies-literature
Project description:Melatonin receptors are members of the G protein-coupled receptor (GPCR) family. Three genes for melatonin receptors have been cloned. The MT1 (or Mel1a or MTNR1A) and MT2 (or Mel1b or MTNR1B) receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype, Mel1c (or MTNR1C), has been identified in fish, amphibians and birds. Another melatonin related orphan receptor, GPR50, which does not bind melatonin, is found exclusively in mammals. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone acts systemically in numerous organs. In the brain, it is involved in the regulation of various neural and endocrine processes, and it readjusts the circadian pacemaker, the suprachiasmatic nucleus. This article reviews recent studies of gene organization, expression, evolution and mutations of melatonin receptor genes of vertebrates. Gene polymorphisms reveal that numerous mutations are associated with diseases and disorders. The phylogenetic analysis of receptor genes indicates that GPR50 is an outgroup to all other melatonin receptor sequences. GPR50 may have separated from a melatonin receptor ancestor before the split between MTNR1C and the MTNR1A/B ancestor.
| S-EPMC3709728 | biostudies-literature
Project description:Capstone courses for upper-division students are a common feature of the undergraduate neuroscience curriculum. Here is described a method for adapting Nikolaas Tinbergen's four questions to use as a framework for a neuroscience capstone course, in this case with a particular emphasis on neurotoxins. This course is intended to be a challenging opportunity for students to integrate and apply knowledge and skills gained from their major study, a B.S. in Biological Sciences with a Concentration in Integrative Physiology and Neurobiology. In particular, a broad, integrative approach is favored, with emphasis placed on primary literature, scientific process and effective, professional communication. To achieve this, Tinbergen's four questions were adapted and implemented as the overarching framework of the course. Tinbergen's questions range from the proximate to ultimate/evolutionary view, providing an excellent base upon which to teach students an integrative approach to understanding neuroscientific phenomena. For example, a particular neurotoxin can be examined from the proximate level (i.e., mechanism: how does this toxin specifically impact neural physiology) to the ultimate/evolutionary level (i.e., adaptation: why and to what extent did this toxin evolve naturally or the reason that it was initially invented by humans). The mechanics, goals, and objectives of the course are presented as we believe that it will serve as a flexible and useful model for neuroscience capstone courses concerning a wide variety of topics across multiple types of institutions.
| S-EPMC4640482 | biostudies-literature
Project description:Seasonal reproduction represents a naturally occurring example of functional plasticity in the adult brain as it reflects changes in neuroendocrine pathways controlling gonadotropin-releasing hormone (GnRH) secretion and, in particular, the responsiveness of GnRH neurons to estradiol negative feedback. Structural plasticity within this neural circuitry may, in part, be responsible for seasonal switches in the negative feedback control of GnRH secretion that underlie annual reproductive transitions. We review evidence for structural changes in the circuitry responsible for seasonal inhibition of GnRH secretion in sheep. These include changes in synaptic inputs onto GnRH neurons, as well as onto dopamine neurons in the A15 cell group, a nucleus that plays a key role in estradiol negative feedback. We also present preliminary data suggesting a role for neurotrophins and neurotrophin receptors as an early mechanistic step in the plasticity that accompanies seasonal reproductive transitions in sheep. Finally, we review recent evidence suggesting that kisspeptin cells of the arcuate nucleus constitute a critical intermediary in the control of seasonal reproduction. Although a majority of the data for a role of neuronal plasticity in seasonal reproduction has come from the sheep model, the players and principles are likely to have relevance for reproduction in a wide variety of vertebrates, including humans, and in both health and disease.
| S-EPMC3059776 | biostudies-literature
Project description:The shape of the association between age and the cost of reproduction varies across species. However, it is unclear whether there are any general patterns in the way the cost of reproduction varies with life history, taxon or ecological function. Using a simple theoretical method, we identified three characteristic patterns to describe the age-related survival cost of reproduction. The most frequent pattern is an approximately exponential decay (ED) with increasing age. Two additional u-shaped patterns were identified, where the cost of reproduction was higher for young and old individuals compared with intermediate-aged individuals. The majority of these u-shaped curves suggested higher costs of reproduction at older ages (RQ), with the rest suggesting a higher cost at young ages (LQ). While predators were most likely to exhibit ED-shaped cost curves, herbivores were equally likely to exhibit ED and RQ curves; birds were likely to exhibit ED-shaped curves and mammals were split equally between ED and RQ curves. These findings suggest that there may be predictable differences in the age-related shape of the cost of reproduction between species, but further research is required to identify the mechanisms generating such differences.
| S-EPMC2391220 | biostudies-literature
Project description:The magnitude of the stimulus to the biological clock will depend upon the distribution of circadian phototransduction circuits across the retinae and the spatial distribution of luminous stimuli in the environment. The present study compared nocturnal melatonin suppression for light exposures to the superior, inferior, nasal, and temporal retina in one eye independent of shading from the brow and the nose. The stimulus was a 40° diameter luminous disc, half of which was blue light (LED, λpeak = 470 nm) and the other amber light (LED, λpeak = 590 nm). Experimentally, the orientation of the bipartite disc was rotated to each of the four cardinal points of the visual field. A full, 40° blue disc was also employed by replacing the amber half-disc with another blue half-disc. The blue full- and half-discs always produced 100 photopic lx at the cornea. As hypothesized, nocturnal melatonin suppression was statistically greatest when the blue half-disc was delivered to the nasal hemi-field (35%); the other three hemi-fields were equally affected by the blue half-disc (≈20%). Melatonin suppression for the full-disc was 24%, which was not statistically different than the average suppression for the four hemi-fields of 27%.
| S-EPMC8099627 | biostudies-literature
Project description:Whether learning primarily reflects general processes or species-specific challenges is a long-standing matter of dispute. Here, we present a comprehensive analysis of public information use (PI-use) in sticklebacks (Gasterosteidae). PI-use is a form of social learning by which animals are able to assess the relative quality of resources, here prey patches, by observing the behaviour of others. PI-use was highly specific with only Pungitius and their closest relative Culaea inconstans showing evidence of PI-use. We saw no effects of ontogenetic experience upon PI-use in Pungitius pungitius. Experiments with live demonstrators and animated fish revealed that heightened activity and feeding strikes by foraging conspecifics are important cues in the transmission of PI. Finally, PI-use was the only form of learning in which P. pungitius and another stickleback, Gasterosteus aculeatus differed. PI-use in sticklebacks is species-specific and may represent an 'ecological specialization' for social foraging. Whether this reflects selection on perception, attentional or cognitive processes remains to be determined.
| S-EPMC6408396 | biostudies-literature
Project description:OBJECTIVE:N-terminal acetylation is a common protein modification that occurs preferentially co-translationally as the substrate N-terminus is emerging from the ribosome. The major N-terminal acetyltransferase complex A (NatA) is estimated to N-terminally acetylate more than 40% of the human proteome. To form a functional NatA complex the catalytic subunit NAA10 must bind the auxiliary subunit NAA15, which properly folds NAA10 for correct substrate acetylation as well as anchors the entire complex to the ribosome. Mutations in these two genes are associated with various neurodevelopmental disorders in humans. The aim of this study was to investigate the in vivo functionality of a Schizosaccharomyces pombe NAA15 mutant that is known to prevent NatA from associating with ribosomes, but retains NatA-specific activity in vitro. RESULTS:Here, we show that Schizosaccharomyces pombe NatA can functionally replace Saccharomyces cerevisiae NatA. We further demonstrate that the NatA ribosome-binding mutant Naa15 ?N K6E is unable to rescue the temperature-sensitive growth phenotype of budding yeast lacking NatA. This finding indicates the in vivo importance of the co-translational nature of NatA-mediated N-terminal acetylation.
| S-EPMC6013942 | biostudies-literature
Project description:1. Recent studies of rodent populations have demonstrated that certain parasites can cause juveniles to delay maturation until the next reproductive season. Furthermore, a variety of parasites may share the same host, and evidence is beginning to accumulate showing nonindependent effects of different infections. 2. We investigated the consequences for host population dynamics of a disease-induced period of no reproduction, and a chronic reduction in fecundity following recovery from infection (such as may be induced by secondary infections) using a modified SIR (susceptible, infected, recovered) model. We also included a seasonally varying birth rate as recent studies have demonstrated that seasonally varying parameters can have important effects on long-term host-parasite dynamics. We investigated the model predictions using parameters derived from five different cyclic rodent populations. 3. Delayed and reduced fecundity following recovery from infection have no effect on the ability of the disease to regulate the host population in the model as they have no effect on the basic reproductive rate. However, these factors can influence the long-term dynamics including whether or not they exhibit multiyear cycles. 4. The model predicts disease-induced multiyear cycles for a wide range of realistic parameter values. Host populations that recover relatively slowly following a disease-induced population crash are more likely to show multiyear cycles. Diseases for which the period of infection is brief, but full recovery of reproductive function is relatively slow, could generate large amplitude multiyear cycles of several years in length. Chronically reduced fecundity following recovery can also induce multiyear cycles, in support of previous theoretical studies. 5. When parameterized for cowpox virus in the cyclic field vole populations (Microtus agrestis) of Kielder Forest (northern England), the model predicts that the disease must chronically reduce host fecundity by more than 70%, following recovery from infection, for it to induce multiyear cycles. When the model predicts quasi-periodic multiyear cycles it also predicts that seroprevalence and the effective date of onset of the reproductive season are delayed density-dependent, two phenomena that have been recorded in the field.
| S-EPMC2408661 | biostudies-literature
Project description:The integrated stress response (ISR) is a cytoprotective pathway initiated upon phosphorylation of the eukaryotic translation initiation factor 2 (eIF2?) residue designated serine-51, which is critical for translational control in response to various stress conditions. Four eIF2? kinases, namely heme-regulated inhibitor (HRI), protein kinase R (PKR), PKR-like endoplasmic reticulum kinase, (PERK) and general control non-depressible 2 (GCN2), have been identified thus far, and they are known to be activated by heme depletion, viral infection, endoplasmic reticulum stress, and amino acid starvation, respectively. Because eIF2? is phosphorylated under various stress conditions, the existence of an additional eIF2? kinase has been suggested. To validate the existence of the unidentified eIF2? kinase, we constructed an eIF2? kinase quadruple knockout cells (4KO cells) in which the four known eIF2? kinase genes were deleted using the CRISPR/Cas9-mediated genome editing. Phosphorylation of eIF2? was completely abolished in the 4KO cells by various stress stimulations. Our data suggests that the four known eIF2? kinases are sufficient for ISR and that there are no additional eIF2? kinases in vertebrates.
| S-EPMC5025754 | biostudies-literature