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2.
J Inorg Biochem ; 229: 111745, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35121188

RESUMO

A conservative characteristic of manganese superoxide dismutase is the rapid formation of product inhibition at high temperatures. At lower temperatures, the enzyme is less inhibited and undergoes more catalytic fast cycles before being product-inhibited. The temperature-dependent kinetics could be rationalized by the temperature-dependent coordination in the conserved center of manganese superoxide dismutase. As temperature decreases, a water molecule (WAT2) approaches or even coordinates Mn as the sixth ligand to interfere with O2•--Mn coordination and reduce product inhibition, so the dismutation should mainly proceed in the fast outer-sphere pathway at low temperatures. Cold-activation is an adaptive response to low temperature rather than a passive adaptation to excess superoxide levels since the cold-activated dismutase activity significantly exceeds the amount of superoxide in the cell or mitochondria. Physiologically speaking, cold activation of manganese superoxide dismutase mediates cold stress signaling and transduces temperature (physical signal) degree into H2O2 fluxes (chemical signal), which in turn may act as a second messenger to induce a series of physiological responses such as cold shock.


Assuntos
Superóxido Dismutase/metabolismo , Termorreceptores/metabolismo , Bactérias/enzimologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Temperatura Baixa , Resposta ao Choque Frio/fisiologia , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Fungos/enzimologia , Humanos , Peróxido de Hidrogênio/metabolismo , Manganês/química , Estresse Oxidativo/fisiologia , Conformação Proteica , Transdução de Sinais/fisiologia , Superóxido Dismutase/química , Superóxidos/química , Superóxidos/metabolismo , Termorreceptores/química
3.
Artigo em Inglês | MEDLINE | ID: mdl-34886305

RESUMO

INTRODUCTION: The method of limits (MLI) and method of level (MLE) are commonly employed for the quantitative assessment of cutaneous thermal sensitivity. Thermal sensation and thermal comfort are closely related and thermal sensations evoked from the peripheral thermoreceptors play an important role in thermoregulatory response to maintain normal body temperature. The purpose of this study was to compare the regional distribution of cutaneous warm and cold sensitivity between MLI and the method of sensation magnitude (MSM). METHOD: Twenty healthy men completed MLI and MSM to compare the regional distribution of cutaneous warm and cold sensitivity in the thermal neutral condition. The subjects rested on a bed in a supine position for 20 min. Next, the cutaneous thermal sensitivity of ten body sites was assessed by the means of MLI and MSM for both warmth and cold stimuli. RESULTS: The absolute mean heat flux in MLI and thermal sensation magnitude in MSM showed significantly greater sensitivity to cold than to warm stimulation (p < 0.01), together with a similar pattern of regional differences across ten body sites. Both sensory modalities indicated acceptable reliability (SRD%: 6.29-8.66) and excellent reproducibility (ICC: 0.826-0.906; p < 0.01). However, the Z-sore distribution in MSM was much narrower than in MLI, which may limit the test sensitivity for the detection of sensory disorders and/or comparison between individuals. CONCLUSION: The present results showed that both MLI and MSM are effective means for evaluating regional cutaneous thermal sensitivity to innocuous warm and cold stimulations to a strong degree of reliability and reproducibility.


Assuntos
Termorreceptores , Sensação Térmica , Temperatura Baixa , Humanos , Masculino , Reprodutibilidade dos Testes , Fenômenos Fisiológicos da Pele
4.
Am J Physiol Regul Integr Comp Physiol ; 321(2): R91-R99, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34075801

RESUMO

Human thermoregulatory control is often evaluated through the relationship between thermoeffector output and core or mean body temperature. In addition to providing a general indication of whether a variable of interest alters thermoregulatory control, this relationship is often used to determine how this alteration may occur. This latter interpretation relies upon two parameters of the thermoeffector output-body temperature relationship: the onset threshold and thermosensitivity. Traditionally, changes in the onset threshold and thermosensitivity are interpreted as "central" or "peripheral" modulation of thermoregulatory control, respectively. This mini-review revisits the origins of the thermoeffector output-body temperature relationship and its use to interpret "central" or "peripheral" modulation of thermoregulatory control. Against this background, we discuss the strengths and weaknesses of this approach and highlight that "central" thermoregulatory control reflects the neural control of body temperature whereas "peripheral" thermoregulatory control reflects properties specific to the thermoeffector organs. We highlight studies that employed more direct approaches to investigate the neural control of body temperature and peripheral properties of thermoeffector organs. We conclude by encouraging future investigations interested in studying thermoregulatory control to more directly investigate the component of the thermoeffector loop under investigation.heat; human; skin blood flow; sweat; thermoregulatory.


Assuntos
Sistema Nervoso Autônomo/fisiologia , Vasos Sanguíneos/inervação , Encéfalo/fisiologia , Temperatura Cutânea , Pele/irrigação sanguínea , Sudorese , Termorreceptores/fisiologia , Vasodilatação , Humanos , Modelos Biológicos , Fluxo Sanguíneo Regional , Sensação Térmica
5.
Indoor Air ; 31(6): 2266-2280, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34048603

RESUMO

Research into human thermal perception indoors has focused on "neutrality" under steady-state conditions. Recent interest in thermal alliesthesia has highlighted the hedonic dimension of our thermal world that has been largely overlooked by science. Here, we show the activity of sensory neurons can predict thermal pleasure under dynamic exposures. A numerical model of cutaneous thermoreceptors was applied to skin temperature measurements from 12 human subjects. A random forest model trained on simulated thermoreceptor impulses could classify pleasure responses (F1 score of 67%) with low false positives/negatives (4%). Accuracy increased (83%) when excluding the few extreme (dis)pleasure responses. Validation on an independent dataset confirmed model reliability. This is the first empirical demonstration of the relationship between thermoreceptors and pleasure arising from thermal stimuli. Insights into the neurophysiology of thermal perception can enhance the experience of built environments through designs that promote sensory excitation instead of neutrality.


Assuntos
Poluição do Ar em Ambientes Fechados , Termorreceptores , Humanos , Prazer , Reprodutibilidade dos Testes , Temperatura Cutânea
6.
J Med Entomol ; 58(4): 1626-1637, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-33704449

RESUMO

The bed bug, Cimex lectularius L., is a common ectoparasite found to live among its vertebrate hosts. Antennal segments in bugs are critical for sensing multiple cues in the environment for survival. To determine whether the thermo receptors of bed bugs are located on their antennae; innovative bioassays were created to observe the choice between heated and unheated stimuli and to characterize the response of bugs to a heat source. Additionally, the effect of complete antenectomized segments on heat detection were evaluated. Heat, carbon dioxide, and moisture are cues that are found to activate bed bug behavior; a temperature at 38°C was used to assess the direction/degree at which the insect reacts to the change in distance from said stimulus. Using a lightweight spherical ball suspended by air through a vacuum tube, bed bugs and other insects are able to move in 360° while on a stationary point. Noldus EthoVision XT was used to capture video images and to track the bed bugs during 5-min bioassays. A bioassay was created using four Petri dish arenas to observe bed bug attraction to heat based on antennae segments at 40°C. The purpose of this study was to evaluate the effects of heat on complete antenectomized segments of the antennae. The results in this experiment suggest that bed bugs detect and are attracted to heat modulated by nutritional status. Learning the involvement of antennae segments in heat detection will help identify the location and role of thermoreceptors for bed bug host interaction.


Assuntos
Percevejos-de-Cama/fisiologia , Sensilas/fisiologia , Resposta Táctica , Termorreceptores/fisiologia , Animais , Percevejos-de-Cama/ultraestrutura , Feminino , Temperatura Alta , Masculino , Sensilas/ultraestrutura
7.
J Laryngol Otol ; 135(2): 104-109, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33612130

RESUMO

BACKGROUND: The mechanism of nasal airflow sensation is poorly understood. This study aimed to examine the role of nasal mucosal temperature change in the subjective perception of nasal patency and the methods by which it can be quantified. METHOD: Medline and PubMed database searches were performed to retrieve literature relevant to the topic. RESULTS: The primary mechanism producing the sensation of nasal patency is thought to be the activation of transient receptor potential melastatin family member 8 ('TRPM8'), a thermoreceptor that is activated by nasal mucosal cooling. Computational fluid dynamics studies have demonstrated that increased airflow and heat flux are correlated with better patient-reported outcome measure scores. Similarly, physical measurements of the nasal cavity using temperature probes have shown a correlation between lower nasal mucosal temperatures and better patient-reported outcome measure scores. CONCLUSION: Nasal mucosal temperature change may be correlated with the perception of improved nasal patency. Future research should quantify the impact of mucosal cooling on the perception of nasal airway obstruction.


Assuntos
Temperatura Baixa/efeitos adversos , Mucosa Nasal/fisiologia , Obstrução Nasal/psicologia , Percepção/fisiologia , Resistência das Vias Respiratórias/fisiologia , Simulação por Computador , Humanos , Hidrodinâmica , Cavidade Nasal/anatomia & histologia , Cavidade Nasal/diagnóstico por imagem , Cavidade Nasal/fisiologia , Mucosa Nasal/metabolismo , Obstrução Nasal/diagnóstico , Obstrução Nasal/fisiopatologia , Obstrução Nasal/cirurgia , Medidas de Resultados Relatados pelo Paciente , Ventilação Pulmonar/fisiologia , Canais de Cátion TRPM/metabolismo , Temperatura , Termorreceptores/metabolismo
8.
Adv Exp Med Biol ; 1349: 355-370, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35138622

RESUMO

Ambient temperature detection and core body temperature maintenance are critical for the environment adaptability of mammals, requiring an elaborate neural network that converts the temperature information sensed by thermoreceptors into physiological and behavioral thermoregulatory responses. The molecular basis of thermosensation lies in the activation of various thermosensitive ion channels with distinct temperature thresholds expressed on the cell membrane of sensory neurons. These channels are able to convert thermal stimuli into electrical activities by gating ions into and out of the cell. In this chapter, we briefly introduce the physiological functions of the main thermosensitive ion channels involved in the core body temperature homeostasis orchestrated by the neural circuits in the peripheral and central nerve systems.


Assuntos
Regulação da Temperatura Corporal , Termorreceptores , Animais , Íons , Mamíferos , Neurônios Aferentes
9.
PLoS One ; 15(8): e0237347, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785272

RESUMO

Here we examine a class of neurons that have been recently explored, the somatosensory neuronal subclass of cold thermosensors. We create a mathematical model of a cold sensing neuron that has been formulated to understand the variety of ionic channels involved. In particular this model showcases the role of TRPM8 and voltage gated potassium channels in setting the temperature dependent activation and inactivation threshold level. Bifurcation analysis of the model demonstrates that a Hodgkin-Huxley type model with additional TRPM8 channels is sufficient to replicate observable experimental features of when different threshold level cold thermosensors turn on. Additionally, our analysis gives insight into what is happening at the temperature levels at which these neurons shut off and the role sodium and leak currents may have in this. This type of model construction and analysis provides a framework moving forward that will help tackle less well understood neuronal classes and their important ionic channels.


Assuntos
Temperatura Baixa , Modelos Neurológicos , Canais de Cátion TRPM/metabolismo , Termorreceptores/fisiologia , Sensação Térmica/fisiologia , Animais , Potenciais da Membrana/fisiologia , Potássio/metabolismo , Sódio/metabolismo
10.
Mol Cell Endocrinol ; 518: 110986, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-32835783

RESUMO

Thermoregulation is critical for survival and animals therefore employ strategies to keep their body temperature within a physiological range. As ectotherms, fish exclusively rely on behavioral strategies for thermoregulation. Different species of fish seek out their specific optimal temperatures through thermal navigation by biasing behavioral output based on experienced environmental temperatures. Like other vertebrates, fish sense water temperature using thermoreceptors in trigeminal and dorsal root ganglia neurons that innervate the skin. Recent research in larval zebrafish has revealed how neural circuits subsequently transform this sensation of temperature into thermoregulatory behaviors. Across fish species, thermoregulatory strategies rely on a modulation of swim vigor based on current temperature and a modulation of turning based on temperature change. Interestingly, temperature preferences are not fixed but depend on other environmental cues and internal states. The following review is intended as an overview on the current knowledge as well as open questions in fish thermoregulation.


Assuntos
Peixes/fisiologia , Termorreceptores/metabolismo , Animais , Comportamento Animal , Regulação da Temperatura Corporal
11.
Int J Biometeorol ; 64(12): 2007-2017, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32820392

RESUMO

A new neurophysiological human thermal model based on thermoreceptor responses, the NHTM model, has been developed to predict regulatory responses and physiological variables in asymmetric transient environments. The passive system is based on Wissler's model, which is more complex and refined. Wissler's model segments the human body into 21 cylindrical parts. Each part is divided into 21 layers, 15 for the tissues and 6 for clothes, and each layer is divided into 12 angular sectors. Thus, we have 3780 nodes for the tissues and 1512 for clothes. The passive system simulates heat exchange within the body and between the body and the surroundings. The active system is composed of the thermoregulatory mechanisms, i.e., skin blood flow, shivering thermogenesis, and sweating. The skin blood flow model and the shivering model are based on thermoreceptor responses. The sweating model is that of Fiala et al. and is based on error signals. The NHTM model was compared with Wissler's model, and the results showed that a calculation based on neurophysiology can improve the performance of the thermoregulation model. The NHTM model was more accurate in the prediction of mean skin temperature, with a mean absolute error of 0.27 °C versus 0.80 °C for the original Wissler model. The prediction accuracy of the NHTM model for local skin temperatures and core temperature could be improved via an optimization method to prove the ability of the new thermoregulation model to fit with the physiological characteristics of different populations.


Assuntos
Neurofisiologia , Termorreceptores , Regulação da Temperatura Corporal , Humanos , Temperatura Cutânea , Sudorese
12.
Curr Biol ; 30(16): 3167-3182.e4, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32619476

RESUMO

Animals exhibit innate and learned preferences for temperature and humidity-conditions critical for their survival and reproduction. Leveraging a whole-brain electron microscopy volume, we studied the adult Drosophila melanogaster circuitry associated with antennal thermo- and hygrosensory neurons. We have identified two new target glomeruli in the antennal lobe, in addition to the five known ones, and the ventroposterior projection neurons (VP PNs) that relay thermo- and hygrosensory information to higher brain centers, including the mushroom body and lateral horn, seats of learned and innate behavior. We present the first connectome of a thermo- and hygrosensory neuropil, the lateral accessory calyx (lACA), by reconstructing neurons downstream of heating- and cooling-responsive VP PNs. A few mushroom body-intrinsic neurons solely receive thermosensory input from the lACA, while most receive additional olfactory and thermo- and/or hygrosensory PN inputs. Furthermore, several classes of lACA-associated neurons form a local network with outputs to other brain neuropils, suggesting that the lACA serves as a hub for thermo- and hygrosensory circuitry. For example, DN1a neurons link thermosensory PNs in the lACA to the circadian clock via the accessory medulla. Finally, we survey strongly connected downstream partners of VP PNs across the protocerebrum; these include a descending neuron targeted by dry-responsive VP PNs, meaning that just two synapses might separate hygrosensory inputs from motor circuits. These data provide a comprehensive first- and second-order layer analysis of Drosophila thermo- and hygrosensory systems and an initial survey of third-order neurons that could directly modulate behavior.


Assuntos
Conectoma , Drosophila melanogaster/fisiologia , Neurônios/metabolismo , Neurópilo/metabolismo , Células Receptoras Sensoriais/metabolismo , Sinapses/fisiologia , Termorreceptores/metabolismo , Animais , Feminino , Neurônios/citologia , Condutos Olfatórios
13.
Int J Mol Sci ; 21(12)2020 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-32580281

RESUMO

TRPM8 is the main molecular entity responsible for cold sensing. This polymodal ion channel is activated by cold, cooling compounds such as menthol, voltage, and rises in osmolality. In corneal cold thermoreceptor neurons (CTNs), TRPM8 expression determines not only their sensitivity to cold, but also their role as neural detectors of ocular surface wetness. Several reports suggest that Protein Kinase C (PKC) activation impacts on TRPM8 function; however, the molecular bases of this functional modulation are still poorly understood. We explored PKC-dependent regulation of TRPM8 using Phorbol 12-Myristate 13-Acetate to activate this kinase. Consistently, recombinant TRPM8 channels, cultured trigeminal neurons, and free nerve endings of corneal CTNs revealed a robust reduction of TRPM8-dependent responses under PKC activation. In corneal CTNs, PKC activation decreased ongoing activity, a key parameter in the role of TRPM8-expressing neurons as humidity detectors, and also the maximal cold-evoked response, which were validated by mathematical modeling. Biophysical analysis indicated that PKC-dependent downregulation of TRPM8 is mainly due to a decreased maximal conductance value, and complementary noise analysis revealed a reduced number of functional channels at the cell surface, providing important clues to understanding the molecular mechanisms of how PKC activity modulates TRPM8 channels in CTNs.


Assuntos
Temperatura Baixa , Neurônios/metabolismo , Proteína Quinase C/metabolismo , Canais de Cátion TRPM/metabolismo , Termorreceptores/metabolismo , Sensação Térmica , Nervo Trigêmeo/metabolismo , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/citologia , Células Receptoras Sensoriais/metabolismo , Nervo Trigêmeo/citologia
14.
Cell Rep ; 30(13): 4505-4517.e5, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32234483

RESUMO

TRPM8 is the main ion channel responsible for cold transduction in the somatosensory system. Nerve terminal availability of TRPM8 determines cold sensitivity, but how axonal secretory organelles control channel delivery remains poorly understood. Here we examine the distribution of TRPM8 and trafficking organelles in cold-sensitive peripheral axons and disrupt trafficking by targeting the ARF-GEF GBF1 pharmacologically or the small GTPase RAB6 by optogenetics. In axons of the sciatic nerve, inhibition of GBF1 interrupts TRPM8 trafficking and increases association with the trans-Golgi network, LAMP1, and Golgi satellites, which distribute profusely along the axonal shaft. Accordingly, both TRPM8-dependent ongoing activity and cold-evoked responses reversibly decline upon GBF1 inhibition in nerve endings of corneal cold thermoreceptors. Inhibition of RAB6, which also associates to Golgi satellites, decreases cold-induced responses in vivo. Our results support a non-conventional axonal trafficking mechanism controlling the availability of TRPM8 in axons and cold sensitivity in the peripheral nervous system.


Assuntos
Axônios/metabolismo , Temperatura Baixa , Organelas/metabolismo , Canais de Cátion TRPM/metabolismo , Animais , Axônios/efeitos dos fármacos , Complexo de Golgi/efeitos dos fármacos , Complexo de Golgi/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Células HEK293 , Células HeLa , Humanos , Masculino , Mentol/farmacologia , Camundongos , Optogenética , Organelas/efeitos dos fármacos , Ligação Proteica/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/metabolismo , Termorreceptores/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo
15.
J Neurogenet ; 34(3-4): 351-362, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32316810

RESUMO

Caenorhabditis elegans has a simple nervous system of 302 neurons. It however senses environmental cues incredibly precisely and produces various behaviors by processing information in the neural circuit. In addition to classical genetic analysis, fluorescent proteins and calcium indicators enable in vivo monitoring of protein dynamics and neural activity on either fixed or free-moving worms. These analyses have provided the detailed molecular mechanisms of neuronal and systemic signaling that regulate worm responses. Here, we focus on responses of C. elegans against temperature and review key findings that regulate thermotaxis and cold tolerance. Thermotaxis of C. elegans has been studied extensively for almost 50 years, and cold tolerance is a relatively recent concept in C. elegans. Although both thermotaxis and cold tolerance require temperature sensation, the responsible neurons and molecular pathways are different, and C. elegans uses the proper mechanisms depending on its situation. We summarize the molecular mechanisms of the major thermosensory circuit as well as the modulatory strategy through neural and tissue communication that enables fine tuning of thermotaxis and cold tolerance.


Assuntos
Aprendizagem da Esquiva/fisiologia , Caenorhabditis elegans/fisiologia , Temperatura Baixa/efeitos adversos , Resposta Táctica/fisiologia , Sensação Térmica/fisiologia , Adaptação Fisiológica/genética , Adaptação Fisiológica/fisiologia , Animais , Caenorhabditis elegans/citologia , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/fisiologia , Sinalização do Cálcio/fisiologia , Dendritos/ultraestrutura , Interneurônios/fisiologia , Mamíferos/fisiologia , Memória/fisiologia , Vias Neurais/fisiologia , Oxigênio/farmacologia , Órgãos dos Sentidos/inervação , Órgãos dos Sentidos/fisiologia , Células Receptoras Sensoriais/classificação , Células Receptoras Sensoriais/fisiologia , Especificidade da Espécie , Termorreceptores/fisiologia
16.
Proc Natl Acad Sci U S A ; 117(11): 6178-6188, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32123108

RESUMO

The nervous system evaluates environmental cues and adjusts motor output to ensure navigation toward a preferred environment. The nematode Caenorhabditis elegans navigates in the thermal environment and migrates toward its cultivation temperature by moving up or down thermal gradients depending not only on absolute temperature but on relative difference between current and previously experienced cultivation temperature. Although previous studies showed that such thermal context-dependent opposing migration is mediated by bias in frequency and direction of reorientation behavior, the complete neural pathways-from sensory to motor neurons-and their circuit logics underlying the opposing behavioral bias remain elusive. By conducting comprehensive cell ablation, high-resolution behavioral analyses, and computational modeling, we identified multiple neural pathways regulating behavioral components important for thermotaxis, and demonstrate that distinct sets of neurons are required for opposing bias of even single behavioral components. Furthermore, our imaging analyses show that the context-dependent operation is evident in sensory neurons, very early in the neural pathway, and manifested by bidirectional responses of a first-layer interneuron AIB under different thermal contexts. Our results suggest that the contextual differences are encoded among sensory neurons and a first-layer interneuron, processed among different downstream neurons, and lead to the flexible execution of context-dependent behavior.


Assuntos
Comportamento Animal/fisiologia , Caenorhabditis elegans/fisiologia , Interneurônios/fisiologia , Navegação Espacial/fisiologia , Termorreceptores/fisiologia , Animais , Técnicas de Observação do Comportamento , Locomoção/fisiologia , Vias Neurais/fisiologia , Temperatura , Sensação Térmica/fisiologia
17.
Biol Rev Camb Philos Soc ; 95(3): 802-821, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32035015

RESUMO

Surviving changing climate conditions is particularly difficult for organisms such as insects that depend on environmental temperature to regulate their physiological functions. Insects are extremely threatened by global warming, since many do not have enough physiological tolerance even to survive continuous exposure to the current maximum temperatures experienced in their habitats. Here, we review literature on the physiological mechanisms that regulate responses to heat and provide heat tolerance in insects: (i) neuronal mechanisms to detect and respond to heat; (ii) metabolic responses to heat; (iii) thermoregulation; (iv) stress responses to tolerate heat; and (v) hormones that coordinate developmental and behavioural responses at warm temperatures. Our review shows that, apart from the stress response mediated by heat shock proteins, the physiological mechanisms of heat tolerance in insects remain poorly studied. Based on life-history theory, we discuss the costs of heat tolerance and the potential evolutionary mechanisms driving insect adaptations to high temperatures. Some insects may deal with ongoing global warming by the joint action of phenotypic plasticity and genetic adaptation. Plastic responses are limited and may not be by themselves enough to withstand ongoing warming trends. Although the evidence is still scarce and deserves further research in different insect taxa, genetic adaptation to high temperatures may result from rapid evolution. Finally, we emphasize the importance of incorporating physiological information for modelling species distributions and ecological interactions under global warming scenarios. This review identifies several open questions to improve our understanding of how insects respond physiologically to heat and the evolutionary and ecological consequences of those responses. Further lines of research are suggested at the species, order and class levels, with experimental and analytical approaches such as artificial selection, quantitative genetics and comparative analyses.


Assuntos
Temperatura Alta , Insetos/fisiologia , Termotolerância/fisiologia , Adaptação Fisiológica , Animais , Metabolismo Basal/fisiologia , Evolução Biológica , Tamanho Corporal , Regulação da Temperatura Corporal/fisiologia , Aquecimento Global , Proteínas de Choque Térmico/metabolismo , Insetos/anatomia & histologia , Insetos/classificação , Fenótipo , Estresse Fisiológico/fisiologia , Termorreceptores/fisiologia
18.
Science ; 367(6478): 681-684, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32029627

RESUMO

Mosquitoes transmit pathogens that kill >700,000 people annually. These insects use body heat to locate and feed on warm-blooded hosts, but the molecular basis of such behavior is unknown. Here, we identify ionotropic receptor IR21a, a receptor conserved throughout insects, as a key mediator of heat seeking in the malaria vector Anopheles gambiae Although Ir21a mediates heat avoidance in Drosophila, we find it drives heat seeking and heat-stimulated blood feeding in Anopheles At a cellular level, Ir21a is essential for the detection of cooling, suggesting that during evolution mosquito heat seeking relied on cooling-mediated repulsion. Our data indicate that the evolution of blood feeding in Anopheles involves repurposing an ancestral thermoreceptor from non-blood-feeding Diptera.


Assuntos
Anopheles/fisiologia , Temperatura Corporal , Evolução Molecular , Comportamento de Busca por Hospedeiro/fisiologia , Temperatura Alta , Receptores Ionotrópicos de Glutamato/fisiologia , Termorreceptores/fisiologia , Animais , Anopheles/genética , Sangue , Feminino , Camundongos , Mutação , Receptores Ionotrópicos de Glutamato/genética
19.
Am J Physiol Regul Integr Comp Physiol ; 318(3): R579-R589, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31967850

RESUMO

In contrast to other species, humans are believed to lack hygroreceptors for sensing skin wetness. Yet, the molecular basis of human hygrosensation is currently unknown, and it remains unclear whether we possess a receptor-mediated sensing mechanism for skin wetness. The aim of this study was to assess the role of the cutaneous cold-sensitive transient receptor potential melastatin-8 (TRPM8) channel as a molecular mediator of human hygrosensation. To this end, we exploited both the thermal and chemical activation of TRPM8-expressing cutaneous Aδ cold thermoreceptors, and we assessed wetness sensing in healthy young men in response to 1) dry skin cooling in the TRPM8 range of thermosensitivity and 2) application of the TRPM8 agonist menthol. Our results indicate that 1) independently of contact with moisture, a cold-dry stimulus in the TRPM8 range of activation induced wetness perceptions across 12 different body regions and those wetness perceptions varied across the body following regional differences in cold sensitivity; and 2) independently of skin cooling, menthol-induced stimulation of TRPM8 triggered wetness perceptions that were greater than those induced by physical dry cooling and by contact with an aqueous cream containing actual moisture. For the first time, we show that the cutaneous cold-sensing TRPM8 channel plays the dual role of cold and wetness sensor in human skin and that this ion channel is a peripheral mediator of human skin wetness perception.


Assuntos
Temperatura Baixa , Temperatura Cutânea/fisiologia , Canais de Cátion TRPM/metabolismo , Termorreceptores/fisiologia , Temperatura Baixa/efeitos adversos , Gânglios Espinais/fisiologia , Humanos , Células Receptoras Sensoriais/fisiologia , Sensação Térmica/fisiologia , Canais de Potencial de Receptor Transitório/metabolismo
20.
Mol Microbiol ; 113(3): 588-592, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31971637

RESUMO

An outstanding question regards the ability of organisms to sense their environments and respond in a suitable way. Pathogenic bacteria in particular exploit host-temperature sensing as a cue for triggering virulence gene expression. This micro-review does not attempt to fully cover the field of bacterial thermosensors and in detail describe each identified case. Instead, the review focus on the time-period at the end of the 1990's and beginning of the 2000's when several key discoveries were made, identifying protein, DNA and RNA as potential thermosensors controlling gene expression in several different bacterial pathogens in general and on the prfA thermosensor of Listeria monocytogenes in particular.


Assuntos
Bactérias/metabolismo , Interações entre Hospedeiro e Microrganismos/fisiologia , Termorreceptores/fisiologia , Bactérias/patogenicidade , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/genética , Temperatura Alta , Listeria monocytogenes/metabolismo , Fatores de Terminação de Peptídeos/genética , Fatores de Terminação de Peptídeos/metabolismo , RNA/genética , RNA/metabolismo , Termorreceptores/metabolismo , Sensação Térmica/genética , Sensação Térmica/fisiologia , Transativadores/metabolismo , Virulência/genética , Fatores de Virulência/genética
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