RESUMEN
Short-term synaptic plasticity alters synaptic efficacy on a timescale that is relevant to encoding information in spike trains. The dynamics of this plasticity, combined with that of the feedback and feedforward contributions of local interneurons, impose frequency-dependent properties on neuronal networks with implications for nervous system function. The trisynaptic network of the hippocampus is especially well suited to selectively filter components of frequency-dependent signals that are transmitted from the entorhinal cortex. We measured presynaptic [Ca(2+)](i) in perforant path, mossy fiber, or Schaffer collateral terminals while simultaneously measuring field potentials of principal cells of the dentate, CA3, or CA1 synaptic fields over a range of stimulus frequencies of 2 to 77 Hz. In all three synaptic fields, the average [Ca(2+)](i) during a 500 ms stimulus train rose monotonically with stimulus frequency. The average population spike amplitude during this stimulus train, however, exhibited a non-linear relationship to frequency that was distinct for each of the three synaptic fields. The dentate synaptic field exhibited the characteristics of a low pass filter, while both CA synaptic fields had bandpass filter characteristics with a gain that was greater than 1 in the passband frequencies. Importantly, alteration of the dynamic properties of this network could significantly impact information processing performed by the hippocampus. Pregnenolone sulfate (PregS), has frequency-dependent effects on paired- and multipulse plasticity in the dentate and CA1 synaptic fields of the hippocampal formation. We investigated the PregS-dependent modulation of the dynamic properties of transmission by the principal cells of the three hippocampal synaptic fields. Importantly, PregS is capable of altering the pattern separation capabilities that may underlie hippocampal information processing.
Asunto(s)
Región CA1 Hipocampal/efectos de los fármacos , Región CA3 Hipocampal/efectos de los fármacos , Giro Dentado/efectos de los fármacos , Corteza Entorrinal/efectos de los fármacos , Red Nerviosa/fisiología , Plasticidad Neuronal/efectos de los fármacos , Pregnenolona/farmacología , Transmisión Sináptica/efectos de los fármacos , Animales , Relojes Biológicos , Región CA1 Hipocampal/fisiología , Región CA3 Hipocampal/fisiología , Señalización del Calcio/efectos de los fármacos , Señalización del Calcio/fisiología , Giro Dentado/fisiología , Corteza Entorrinal/fisiología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Excitadores/fisiología , Retroalimentación Fisiológica/efectos de los fármacos , Retroalimentación Fisiológica/fisiología , Neuronas GABAérgicas/fisiología , Interneuronas/fisiología , Fibras Musgosas del Hipocampo/efectos de los fármacos , Fibras Musgosas del Hipocampo/fisiología , Plasticidad Neuronal/fisiología , Vía Perforante/efectos de los fármacos , Vía Perforante/fisiología , Terminales Presinápticos/efectos de los fármacos , Terminales Presinápticos/fisiología , Células Piramidales/fisiología , Ratas , Ratas Sprague-Dawley , Transmisión Sináptica/fisiología , Ritmo Teta/efectos de los fármacos , Ritmo Teta/fisiologíaRESUMEN
Seminal fluid proteins (Sfps) alter female behaviour and physiology and can mediate sexual conflict. In Drosophila melanogaster, a single Sfp, the sex peptide (SP), triggers remarkable post-mating responses in females, including altered fecundity, feeding, immunity and sexual receptivity. These effects can favour the evolutionary interests of males while generating costs in females. We tested the hypothesis that SP is an upstream master-regulator able to induce diverse phenotypes through efficient induction of widespread transcriptional changes in females. We profiled mRNA responses to SP in adult female abdomen (Abd) and head+thorax (HT) tissues using microarrays at 3 and 6 h following mating. SP elicited a rich, subtle signature of temporally and spatially controlled mRNAs. There were significant alterations to genes linked to egg development, early embryogenesis, immunity, nutrient sensing, behaviour and, unexpectedly, phototransduction. There was substantially more variation in the direction of differential expression across time points in the HT versus Abd. The results support the idea that SP is an important regulator of gene expression in females. The expression of many genes in one sex can therefore be under the influence of a regulator expressed in the other. This could influence the extent of sexual conflict both within and between loci.
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiología , Regulación de la Expresión Génica , Péptidos/metabolismo , ARN Mensajero/metabolismo , Animales , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Femenino , Masculino , Análisis por Micromatrices , Péptidos/genética , ARN Mensajero/genética , Reproducción , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Conducta Sexual AnimalRESUMEN
INTRODUCTION: The clinical application of the arts among military personnel and veterans has been well documented, particularly in relation to service-related mental health difficulties. However, the impacts of engaging recreationally with art activities on general well-being remain underexplored and even more so among those living with visual impairment (VI). This pilot explored the artistic experiences of veterans with VI participating in a remotely delivered art and craft project during continued COVID-19 restrictions in Spring/Summer 2021. METHODS: Six participants received a mystery arts box (MAB) containing a selection of materials, collated to encourage experimentation with unfamiliar techniques. Participants were asked to journal their process as they developed a final piece/pieces. They were invited to join group video calls to share work and ideas and seek guidance. Semistructured interviews were run with participants at the end of the project. Journal and interview data were thematically analysed. RESULTS: Analysis identified 11 themes relating to initial and ongoing responses to the MAB and creative and journalling process. Several benefits were identified, including artistic learning, trying something new, and social, cognitive and emotional experiences. The value of the activity to participants' lives within the context of the ongoing pandemic was also considered. Challenges were associated with the use of unfamiliar materials, impacts of sight loss and the limitations of remote delivery. CONCLUSION: This pilot brings to the fore the everyday artistic experience of veterans living with VI and considers the benefits, challenges and well-being implications of a remotely delivered arts activity. Findings illustrate the importance of ensuring accessibility of artistic activities to those for whom disability might limit participation and highlight the ongoing role that remotely delivered arts activities might play in meeting the social and recreational needs of individuals beyond the COVID-19 pandemic.
RESUMEN
Presynaptic Ca(2+) influx pathways, cytoplasmic Ca(2+) buffering proteins and Ca(2+) extrusion processes undergo considerable change during the first postnatal month in rodent neurons. These changes may be critical in establishing short-term plasticity at maturing presynaptic terminals where neurotransmitter release is directly dependent on the dynamics of cytoplasmic residual Ca(2+) ([Ca(2+)](res)). In particular, the robust paired-pulse facilitation characteristic of adult neurons is almost entirely lacking in newborns. To examine developmental changes in processes controlling [Ca(2+)](res), we measured the timecourse of [Ca(2+)](res) decay in presynaptic terminals of Schaffer collateral to CA1 synapses in acute hippocampal slices following single and paired orthodromic stimuli in the stratum radiatum. Developmental changes were observed in both the rise time and slow exponential decay components of the response to single stimuli such that this decay was larger and faster in the adult. Furthermore, we observed a greater caffeine-sensitive basal Ca(2+) store, which was differentially affected when active uptake into the endoplasmic reticulum was blocked, in the presynaptic fields of the Schaffer collateral to CA1 terminals of P6 and younger mice when compared to adults. These transitions in [Ca(2+)](res) dynamics occurred gradually over the first weeks of postnatal life and correlated with changes in short-term plasticity.
Asunto(s)
Calcio/metabolismo , Hipocampo/crecimiento & desarrollo , Hipocampo/metabolismo , Plasticidad Neuronal/fisiología , Terminales Presinápticos/metabolismo , Animales , Ratones , Ratones Endogámicos C57BL , Técnicas de Cultivo de Órganos , Técnicas de Placa-ClampRESUMEN
Short-term synaptic plasticity undergoes important age-dependent changes that have crucial implications during the development of the nervous system. Paired-pulse facilitation is a form of short-term synaptic plasticity by which the response to the second of two temporally-paired stimuli is larger and more reliable than the response to the first stimulus. In this study, a paired-pulse minimal stimulation technique was used to measure the probability and quantal amplitude of synaptic release at hippocampal synapses from 12-16-day-old (young) and 7-9-week-old (adult) rats. In order to assess the contribution of temperature-dependent processes, we carried out experiments at both room temperature and at near physiological temperature. We report here that neither temperature nor maturation affected the low basal evoked release probability and quantal amplitude of release. However, the warmer temperature revealed a unique developmental increase in facilitated evoked release probability and quantal amplitude of release. As a result, although both basal evoked release and facilitated release are rather unreliable in synapses from young animals, the maturation process at near physiological temperature generates a phenotype with unreliable basal evoked release and highly reliable facilitated release.
Asunto(s)
Hipocampo/crecimiento & desarrollo , Hipocampo/fisiología , Plasticidad Neuronal/fisiología , Sinapsis/fisiología , Transmisión Sináptica/fisiología , Temperatura , Animales , Estimulación Eléctrica , Técnicas In Vitro , Potenciales de la Membrana , Neuronas/fisiología , Técnicas de Placa-Clamp , Probabilidad , Ratas , Ratas Sprague-Dawley , Factores de TiempoRESUMEN
Exposure to ethanol during development triggers neuronal cell death and this is thought to play a central role in the pathophysiology of fetal alcohol spectrum disorder (FASD). Studies suggest that ethanol-induced neurodegeneration during the period of synaptogenesis results from widespread potentiation of GABA(A) receptors and inhibition of NMDA receptors throughout the brain, with neocortical layer II being particularly sensitive. Here, we tested whether ethanol modulates the function of these receptors during this developmental period using patch-clamp electrophysiological and Ca(2+) imaging techniques in acute slices from postnatal day 7-9 rats. We focused on pyramidal neurons in layer II of the parietal cortex (with layer III as a control). Ethanol (70mM) increased spontaneous action potential-dependent GABA release in layer II (but not layer III) neurons without affecting postsynaptic GABA(A) receptors. Protein and mRNA expression for both the Cl(-) importer, NKCC1, and the Cl(-) exporter, KCC2, were detected in layer II/III neurons. Perforated-patch experiments demonstrated that E(Cl)((-)) is shifted to the right of E(m); activation of GABA(A) receptors with muscimol depolarized E(m), decreased action potential firing, and minimally increased [Ca(2+)](i). However, the ethanol-induced increase of GABAergic transmission did not affect neuronal excitability. Ethanol had no effect on currents exogenously evoked by NMDA or AMPA receptor-mediated spontaneous excitatory postsynaptic currents. Acute application of ethanol in the absence of receptor antagonists minimally increased [Ca(2+)](i). These findings are inconsistent with the excessive inhibition model of ethanol-induced neurodegeneration, supporting the view that ethanol damages developing neurons via more complex mechanisms that vary among specific neuronal populations.
Asunto(s)
Depresores del Sistema Nervioso Central/farmacología , Etanol/farmacología , Ácido Glutámico/metabolismo , Neocórtex , Células Piramidales/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Ácido gamma-Aminobutírico/metabolismo , Animales , Animales Recién Nacidos , Biofisica , Calcio/metabolismo , Maleato de Dizocilpina/farmacología , Estimulación Eléctrica/métodos , Antagonistas de Aminoácidos Excitadores , Femenino , Agonistas del GABA/farmacología , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Regulación del Desarrollo de la Expresión Génica/fisiología , Técnicas In Vitro , Masculino , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Muscimol/farmacología , Neocórtex/citología , Neocórtex/efectos de los fármacos , Neocórtex/crecimiento & desarrollo , Técnicas de Placa-Clamp , Embarazo , Ratas , Ratas Sprague-Dawley , Simportadores de Cloruro de Sodio-Potasio/metabolismo , Miembro 2 de la Familia de Transportadores de Soluto 12 , Simportadores/metabolismo , Transmisión Sináptica/fisiología , Cotransportadores de K ClRESUMEN
Evolutionary conflict occurs when the deterministic spread of an allele lowers the fitness either of its bearer or of other individuals in the population, leading to selection for suppressors. Sex promotes conflict because associations between alleles are temporary. Differing selection on males and females, sexual selection, and differences in transmission patterns between classes of nuclear and cytoplasmic genes can all give rise to conflict. Inert Y chromosomes, uniparental inheritance of cytoplasmic genes, mating strains and sexes, and many features of sexual behavior may have evolved in part as a result of evolutionary conflict. Estimates of its quantitative importance, however, are still needed.
Asunto(s)
Alelos , Evolución Biológica , Selección Genética , Sexo , Animales , Femenino , Masculino , Meiosis , Orgánulos/genética , Caracteres Sexuales , Conducta Sexual Animal , Cromosoma Y/genéticaRESUMEN
There is now a good theoretical understanding of life history evolution, and detailed explicit optimality models have been constructed. These present a challenge for empirical work examining some of the assumptions, such as the extent and mechanisms of the costs of growth and reproduction. In addition, there is an obvious need for comparative tests of the models. These tests, properly applied, may be particularly informative because they can deal with multiple independent variables, including ecological variables, and can reveal broad trends against a background of constraints on optima and the rate of evolutionary approach to them. Life histories are the probabilities of survival and the rates of reproduction at each age in the life-span. Reproduction is costly, so that fertility at all ages cannot simultaneously be maximized by natural selection. Allocation of reproductive effort has evolved in response to the demographic impact of different environments but is constrained by genetic variance and evolutionary history.
RESUMEN
Mortality rates typically increase rapidly at the onset of aging but can decelerate at later ages. Reproduction increases the death rate in many organisms. To test the idea that a delayed impact of earlier reproduction contributes to both an increase in death rates and a later deceleration in mortality, the timing of the surplus mortality produced by an increased level of egg production was measured in female Drosophila. Reproduction produced a delayed wave of mortality, coincident with the sharp increase in death rates at the onset of aging and the subsequent deceleration of mortality. These results suggest that aging has evolved primarily because of the damaging effects of reproduction earlier in life, rather than because of mutations that have detrimental effects only at late ages.
Asunto(s)
Envejecimiento , Evolución Biológica , Proteínas de Drosophila , Longevidad , Reproducción , Envejecimiento/genética , Envejecimiento/fisiología , Animales , Cruzamientos Genéticos , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/fisiología , Drosophila melanogaster/efectos de la radiación , Femenino , Fertilidad/fisiología , Genes de Insecto , Hibridación Genética , Longevidad/genética , Longevidad/fisiología , Masculino , Oviposición , Reproducción/genética , Reproducción/fisiología , Selección Genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
The Drosophila melanogaster gene chico encodes an insulin receptor substrate that functions in an insulin/insulin-like growth factor (IGF) signaling pathway. In the nematode Caenorhabditis elegans, insulin/IGF signaling regulates adult longevity. We found that mutation of chico extends fruit fly median life-span by up to 48% in homozygotes and 36% in heterozygotes. Extension of life-span was not a result of impaired oogenesis in chico females, nor was it consistently correlated with increased stress resistance. The dwarf phenotype of chico homozygotes was also unnecessary for extension of life-span. The role of insulin/IGF signaling in regulating animal aging is therefore evolutionarily conserved.
Asunto(s)
Envejecimiento/fisiología , Proteínas de Drosophila , Drosophila melanogaster/fisiología , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Longevidad/fisiología , Proteínas Tirosina Quinasas Receptoras , Receptor de Insulina/metabolismo , Alelos , Animales , Constitución Corporal , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Cruzamientos Genéticos , Drosophila melanogaster/genética , Femenino , Fertilidad , Genes de Insecto , Heterocigoto , Calor , Insulina/metabolismo , Proteínas Sustrato del Receptor de Insulina , Masculino , Mutación , Estrés Oxidativo , Proteínas Tirosina Quinasas/genética , Proteínas Tirosina Quinasas/metabolismo , Reproducción , Transducción de Señal , Somatomedinas/metabolismo , Inanición , Superóxido DismutasaRESUMEN
It is well established that sulfated steroids regulate synaptic transmission by altering the function of postsynaptic neurotransmitter receptors. In recent years, evidence from several laboratories indicates that these agents also regulate glutamatergic synaptic transmission at the presynaptic level in an age-dependent manner. In developing neurons, pregnenolone sulfate (PREGS) increases the probability of glutamate release, as evidenced by an increase in the frequency of AMPA receptor-mediated miniature excitatory postsynaptic currents and a decrease in paired-pulse facilitation. In hippocampal slices from postnatal day 3-5 rats, this effect is mediated by an increase in Ca(2+) levels in the axonal terminal that depends on presynaptic NMDA receptors. This is followed by delayed potentiation of postsynaptic AMPA receptor currents. Importantly, depolarization of postsynaptic neurons, inhibition of hydroxysteroid sulfatase activity and acute exposure to ethanol mimics the effect of exogenous PREGS application. This developmental form of synaptic plasticity cannot be observed in slices from rats older than postnatal day 6, when presynaptic NMDA receptors are no longer expressed in CA1 hippocampal region. Both in the CA1 hippocampal region and the dentate gyrus of more mature rats, PREGS, dehydroepiandrosterone sulfate and hydroxysteroid sulfatase inhibitors increase paired-pulse facilitation, without affecting basal glutamate release probability. This effect depends on activation of sigma(1)-like receptors and G(i/o) and involves a target in the release machinery that is downstream of residual Ca(2+). These presynaptic actions of sulfated steroids could play important roles in physiological processes ranging from synapse maturation to learning and memory, as well as pathophysiological conditions such as fetal alcohol spectrum disorder.
Asunto(s)
Encéfalo/metabolismo , Trastornos del Espectro Alcohólico Fetal/metabolismo , Glutamina/metabolismo , Neuronas/metabolismo , Esteroides/metabolismo , Transmisión Sináptica/fisiología , Animales , Encéfalo/efectos de los fármacos , Encéfalo/embriología , Sulfato de Deshidroepiandrosterona/metabolismo , Etanol/efectos adversos , Femenino , Humanos , Neuronas/efectos de los fármacos , Embarazo , Pregnenolona/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Transmisión Sináptica/efectos de los fármacosRESUMEN
HuD is a neuronal RNA-binding protein associated with the stabilization of mRNAs for GAP-43 and other neuronal proteins that are important for nervous system development and learning and memory mechanisms. To better understand the function of this protein, we generated transgenic mice expressing human HuD (HuD-Tg) in adult forebrain neurons. We have previously shown that expression of HuD in adult dentate granule cells results in an abnormal accumulation of GAP-43 mRNA via posttranscriptional mechanisms. Here we show that this mRNA accumulation leads to the ectopic expression of GAP-43 protein in mossy fibers. Electrophysiological analyses of the mossy fiber to CA3 synapse of HuD-Tg mice revealed increases in paired-pulse facilitation (PPF) at short interpulse intervals and no change in long-term potentiation (LTP). Presynaptic calcium transients at the same synapses exhibited faster time constants of decay, suggesting a decrease in the endogenous Ca(2+) buffer capacity of mossy fiber terminals of HuD-Tg mice. Under resting conditions, GAP-43 binds very tightly to calmodulin sequestering it and then releasing it upon PKC-dependent phosphorylation. Therefore, subsequent studies examined the extent of GAP-43 phosphorylation and its association to calmodulin. We found that despite the increased GAP-43 expression in HuD-Tg mice, the levels of PKC-phosphorylated GAP-43 were decreased in these animals. Furthermore, in agreement with the increased proportion of nonphosphorylated GAP-43, HuD-Tg mice showed increased binding of calmodulin to this protein. These results suggest that a significant amount of calmodulin may be trapped in an inactive state, unable to bind free calcium, and activate downstream signaling pathways. In conclusion, we propose that an unregulated expression of HuD disrupts mossy fiber physiology in adult mice in part by altering the expression and phosphorylation of GAP-43 and the amount of free calmodulin available at the synaptic terminal.
Asunto(s)
Proteínas ELAV/genética , Proteínas ELAV/fisiología , Proteína GAP-43/genética , Proteína GAP-43/fisiología , Fibras Musgosas del Hipocampo/fisiología , Animales , Calcio/metabolismo , Calmodulina/metabolismo , Proteína 4 Similar a ELAV , Electrofisiología , Proteína GAP-43/química , Expresión Génica , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Fosforilación , Terminales Presinápticos/metabolismo , Unión Proteica , Estabilidad del ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMEN
Ageing research has been revolutionized by the use of model organisms to discover genetic alterations that can extend lifespan. In the last 5 years alone, it has become apparent that single gene mutations in the insulin and insulin-like growth-factor signalling pathways can lengthen lifespan in worms, flies and mice, implying evolutionary conservation of mechanisms. Importantly, this research has also shown that these mutations can keep the animals healthy and disease-free for longer and can alleviate specific ageing-related pathologies. These findings are striking in view of the negative effects that disruption of these signalling pathways can also produce. Here, we summarize the body of work that has lead to these discoveries and point out areas of interest for future work in characterizing the genetic, molecular and biochemical details of the mechanisms to achieving a longer and healthier life.
Asunto(s)
Envejecimiento/fisiología , Caenorhabditis elegans/fisiología , Drosophila melanogaster/fisiología , Ratones/fisiología , Envejecimiento/genética , Animales , Insulina/metabolismo , Factor I del Crecimiento Similar a la Insulina/genética , Factor I del Crecimiento Similar a la Insulina/metabolismo , Longevidad/genética , Longevidad/fisiología , Modelos AnimalesRESUMEN
Although the underlying mechanisms of ageing are not understood, it is known that the longevity of the nematode Caenorhabditis elegans is modulated by an insulin/IGF-signalling pathway. The focus now is on how this pathway is regulated, how it controls nematode ageing, and how this relates to the ageing process in higher animals.
Asunto(s)
Envejecimiento/metabolismo , Insulina/metabolismo , Transducción de Señal/fisiología , Somatomedinas/metabolismo , Envejecimiento/fisiología , Animales , Caenorhabditis elegans/fisiología , Drosophila melanogaster/fisiología , Ingestión de Energía , Humanos , RatonesRESUMEN
Axon outgrowth during development and neurotransmitter release depends on exocytotic mechanisms, although what protein machinery is common to or differentiates these processes remains unclear. Here we show that the neural t-SNARE (target-membrane-associated-soluble N-ethylmaleimide fusion protein attachment protein (SNAP) receptor) SNAP-25 is not required for nerve growth or stimulus-independent neurotransmitter release, but is essential for evoked synaptic transmission at neuromuscular junctions and central synapses. These results demonstrate that the development of neurotransmission requires the recruitment of a specialized SNARE core complex to meet the demands of regulated exocytosis.
Asunto(s)
Exocitosis/fisiología , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Neuronas/fisiología , Transmisión Sináptica/fisiología , Proteínas de Transporte Vesicular , Animales , Encéfalo/citología , Encéfalo/embriología , Encéfalo/metabolismo , Células Cultivadas , Dermis/citología , Dermis/metabolismo , Diafragma/metabolismo , Embrión de Mamíferos/fisiología , Desarrollo Embrionario y Fetal , Inmunohistoquímica , Técnicas In Vitro , Proteínas de la Membrana/genética , Ratones , Ratones Noqueados , Músculo Esquelético/citología , Músculo Esquelético/metabolismo , Proteínas del Tejido Nervioso/genética , Unión Neuromuscular/fisiología , Neuronas/ultraestructura , Técnicas de Placa-Clamp , Proteínas SNARE , Proteína 25 Asociada a SinaptosomasRESUMEN
Recent observations of a levelling of the death rate in extreme old age, in both experimental species and humans, are posing difficult problems for evolutionary biologists, in particular about the evolution of the post-reproductive period.
Asunto(s)
Envejecimiento , Modelos Biológicos , Mortalidad , Animales , Evolución Molecular , Heterogeneidad Genética , HumanosRESUMEN
A recent experiment provides evidence that ageing is partly due to mutations with deleterious effects late in life that have been retained in the population as selection against them is weak.
Asunto(s)
Envejecimiento/genética , Anciano , Animales , Evolución Biológica , Femenino , Variación Genética , Geriatría , Humanos , Masculino , Mutación , Selección GenéticaRESUMEN
Fruit fly larvae occur as either 'rovers', which move a long way to find food, or 'sitters', which stay within a more restricted area. This polymorphism is determined by alleles of a cyclic GMP-dependent protein kinase gene; rovers are at an advantage in crowded populations, while sitters have the edge at low population density.
Asunto(s)
Drosophila/genética , Drosophila/fisiología , Conducta Alimentaria/fisiología , Genética Conductual , Conducta Espacial/fisiología , Alelos , Animales , Proteínas Quinasas Dependientes de GMP Cíclico/genética , Drosophila/enzimología , Larva/enzimología , Larva/genética , Larva/fisiologíaRESUMEN
Aging, and the deterioration of biological performance that characterizes it, are routinely assumed to be due to a progressive global loss of homeostasis and a general increase in dysregulation [1-4] . We tested this hypothesis directly by measuring age-specific variability in gene expression. Analysis of the transcriptional activity of six genes in various inbred lines of Drosophila melanogaster unexpectedly failed to show an increase in variability among individuals as they age and die. Although regulation of gene expression is a central feature of life, a global decline in the control of gene expression does not appear to be either a cause or a consequence of the process of aging.