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1.
Int Endod J ; 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38661046

RESUMO

INTRODUCTION: Diagnostic procedures for pulp vitality assessment are a crucial aspect of routine dental practice. This review aims to provide a comprehensive overview of nontraditional techniques and methodologies for assessing pulp vitality, specifically exploring promising approaches that are currently not used in dental practice. METHODS: The study protocol was registered a priori (https://osf.io/3m97z/). An extensive electronic search was conducted across multiple databases, including MEDLINE via PubMed, Scopus, Web of Science, and Embase. Inclusion criteria were guided by the research question based on the PCC model as follows: "What are the potential nontraditional techniques (Concept) for assessing pulp vitality (Population) in the field of endodontics or clinical practice (Context)?" Studies were included that explored possible approaches to pulp vitality assessment, utilizing a range of techniques, whilst any studies using traditional pulp tests (cold, heat, and electric stimulation) or well-known methods (pulse oximetry and laser Doppler flowmetry) were excluded. Reviewers independently screened articles and extracted data. A patent search was also performed. RESULTS: Of 3062 studies, 65 were included that described nontraditional approaches for assessing pulp vitality. These included a range of optical diagnostic methods, ultrasound Doppler flowmetry (UDF), magnetic resonance imaging (MRI), terahertz imaging, tooth temperature measurements, as well as invasive methodologies, including 133xenon washout, radioisotope-labelled tracers, hydrogen gas desaturation, intravital microscopy and fluorescent microspheres isotope clearance. The patent search included artificial intelligence and biomarkers methods. CONCLUSIONS: This review provides details for potential innovative tests that may directly describe pulp vitality. Importantly, these methods range from clinically impractical through to promising methods that may transform clinical practice. Several nontraditional techniques have the potential to enhance diagnostic accuracy and could provide valuable insights into the assessment of pulp vitality in challenging clinical scenarios.

2.
J Exp Biol ; 227(Suppl_1)2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38449322
3.
PLoS One ; 19(3): e0300972, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38536831

RESUMO

Madagascar has a harsh and stochastic climate because of regular natural disturbances. This history of regular cyclones has been hypothesised to have directed evolutionary changes to lemur behaviour and morphology that make them more resilient to sudden environmental change. These adaptations may include: small group sizes, high degrees of energy-conserving behaviours, generalist habitat use, small home ranges, small body size, and a limited number of frugivorous species. To date, however, no one has tested how variation in cyclone exposure across Madagascar is associated with variation in these resilience traits. In this study, we created a detailed cyclone impact map for Madagascar using Koppen-Geiger climate class, historical cyclone tracks, the Saffir Class of cyclone and hurricane intensity, and precipitation data. We also used existing literature to calculate a resilience score for 26 lemur species for which data existed on resilience traits. Our cyclone impact map was then overlaid on known geographic ranges of these species and compared to resilience score while controlling for phylogenetic non-independence and spatial autocorrelation. We found no association between cyclone impact in a lemur range and their resilience score. When assessing traits individually, however, we found that cyclone impact was positively associated with body size, suggesting that the more impacted a species is by cyclones the smaller they are. We also found cyclone impact to be negatively associated with frugivory, with species in higher impact zones eating more fruit. While unexpected, this could reflect an increased production in fruit in tree fall gaps following cyclones. While we did not find a pattern between cyclone impact and behavioural resilience in lemurs, we suggest a similar study at a global scale across all primates would allow for more taxonomic variation and reveal larger patterns key to understanding past and future vulnerability to natural disturbances in primates.


Assuntos
Tempestades Ciclônicas , Lemur , Strepsirhini , Animais , Filogenia , Ecossistema , Demografia , Madagáscar
4.
Artigo em Inglês | MEDLINE | ID: mdl-38043639

RESUMO

Amphibious fishes on land encounter higher oxygen (O2) availability and novel energetic demands, which impacts metabolism. Previous work on the amphibious mangrove killifish (Kryptolebias marmoratus) has shown that cortisol becomes elevated in response to air exposure, suggesting a possible role in regulating metabolism as fish move into terrestrial environments. We tested the hypothesis that cortisol is the mechanism by which oxidative processes are upregulated during the transition to land in amphibious fishes. We used two groups of fish, treated fish (+metyrapone, a cortisol synthesis inhibitor) and control (-metyrapone), to determine the impact of cortisol during air exposure (0 and 1 h, 7 days) on O2 consumption, terrestrial locomotion, the phenotype of red skeletal muscle, and muscle lipid concentration. Metyrapone-treated fish had an attenuated elevation in O2 consumption rate during the water to air transition and an immediate reduction in terrestrial exercise performance relative to control fish. In contrast, we found no short- (0 h) or long-term (7 days) differences between treatments in the oxidative phenotype of red muscles, nor in muscle lipid concentrations. Our results suggest that cortisol stimulates the necessary increase in aerobic metabolism needed to fuel the physiological changes that amphibious fishes undergo during the acclimation to air, although further studies are required to determine specific mechanisms of cortisol regulation.


Assuntos
Ciprinodontiformes , Peixes Listrados , Animais , Ciprinodontiformes/fisiologia , Hidrocortisona/farmacologia , Metirapona/farmacologia , Oxigênio , Lipídeos
5.
J Exp Biol ; 226(24)2023 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-38059428

RESUMO

To celebrate its centenary year, Journal of Experimental Biology (JEB) commissioned a collection of articles examining the past, present and future of experimental biology. This Commentary closes the collection by considering the important research opportunities and challenges that await us in the future. We expect that researchers will harness the power of technological advances, such as '-omics' and gene editing, to probe resistance and resilience to environmental change as well as other organismal responses. The capacity to handle large data sets will allow high-resolution data to be collected for individual animals and to understand population, species and community responses. The availability of large data sets will also place greater emphasis on approaches such as modeling and simulations. Finally, the increasing sophistication of biologgers will allow more comprehensive data to be collected for individual animals in the wild. Collectively, these approaches will provide an unprecedented understanding of 'how animals work' as well as keys to safeguarding animals at a time when anthropogenic activities are degrading the natural environment.


Assuntos
Meio Ambiente , Genômica , Animais
6.
Animals (Basel) ; 13(18)2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37760313

RESUMO

The futures of human and nonhuman primates are closely tied in protected areas. Understanding this interconnectedness is especially urgent in Madagascar, one of the world's most impoverished biodiversity hotspots. Yet, no study has evaluated the relationship between poverty and lemur hunting and consumption using a composite poverty metric that includes health, education, and living standards. To address this gap, and to inform primate conservation practice and policy, we administered annual surveys to 81 households over six consecutive months (September 2018 to March 2019) in a village on the border of Kirindy Mitea National Park, Madagascar. We observed extreme deprivation scores across multiple dimensions of poverty and identified ninety-five percent of households as 'impoverished'. Of these, three-quarters (77%) of households were identified as being in 'severe poverty'. One-fifth (19%) of all households hunted lemurs and half (49%) of households consumed lemurs. While poverty eradication is an urgent need in communities around Kirindy Mitea National Park, our findings show no relationship between poverty and lemur hunting and consumption, perhaps due to the lack of variance in poverty. Our results highlight the need to investigate other contributory factors to lemur hunting and consumption locally. Because food insecurity is a known driver of lemur hunting and consumption among the study community, and because domestic meats can be preferred over protected species, we recommend testing the efficacy of livestock interventions near Kirindy Mitea National Park.

7.
Microbiologyopen ; 12(4): e1377, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37642488

RESUMO

Oral biofilms are three-dimensional (3D) complex entities initiating dental diseases and have been evaluated extensively in the scientific literature using several biofilm models and assessment techniques. The list of biofilm models and assessment techniques may overwhelm a novice biofilm researcher. This narrative review aims to summarize the existing literature on biofilm models and assessment techniques, providing additional information on selecting an appropriate model and corresponding assessment techniques, which may be useful as a guide to the beginner biofilm investigator and as a refresher to experienced researchers. The review addresses previously established 2D models, outlining their advantages and limitations based on the growth environment, availability of nutrients, and the number of bacterial species, while also exploring novel 3D biofilm models. The growth of biofilms on clinically relevant 3D models, particularly melt electrowritten fibrous scaffolds, is discussed with a specific focus that has not been previously reported. Relevant studies on validated oral microcosm models that have recently gaining prominence are summarized. The review analyses the advantages and limitations of biofilm assessment methods, including colony forming unit culture, crystal violet, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt assays, confocal microscopy, fluorescence in situ hybridization, scanning electron microscopy, quantitative polymerase chain reaction, and next-generation sequencing. The use of more complex models with advanced assessment methodologies, subject to the availability of equipment/facilities, may help in developing clinically relevant biofilms and answering appropriate research questions.


Assuntos
Biofilmes , Violeta Genciana , Hibridização in Situ Fluorescente , Sequenciamento de Nucleotídeos em Larga Escala , Microscopia Confocal
8.
J Exp Biol ; 226(12)2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-37366313
9.
Diabetes Obes Metab ; 25(8): 2340-2350, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37188932

RESUMO

AIMS: To investigate the hypothesis that weight loss with the glucagon-like peptide-1 receptor agonist (GLP-1RA) liraglutide alone would lead to a greater reduction in the proportion of fat to lean tissue mass when compared to caloric restriction (CR) alone, as well as when compared to treatment with sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, that also enhances GLP-1 activity - to determine the independent effects of each treatment. METHODS: A total of 88 adults with obesity and prediabetes were randomized to 14 weeks of intervention with CR (-390 kcal/d), liraglutide (1.8 mg/d), or the dipeptidyl peptidase-4 inhibitor sitagliptin (100 mg/d) as a weight-neutral comparator. Changes between groups in appetite and hunger ratings measured via visual analogue scales, dietary intakes, body weight, body composition via dual energy x-ray absorptiometry, and resting energy expenditure via indirect calorimetry were assessed using the Kruskal-Wallis test or Pearson's chi-squared test. RESULTS: Weight loss ≥5% of baseline body weight occurred in 44% of participants in the CR group, 22% of the liraglutide group and 5% of the sitagliptin group (p = 0.02). The ratio of fat to lean mass decreased by 6.5% in the CR group, 2.2% in the liraglutide group, and 0% in the sitagliptin group (p = 0.02). Visceral fat reduced by 9.5% in the CR group, 4.8% in the liraglutide group, and 0% in the sitagliptin group (p = 0.04). A spontaneous reduction in dietary simple carbohydrates in the CR group was associated with improved homeostatic model assessment of insulin resistance score (HOMA-IR). CONCLUSIONS: Although both liraglutide and CR are valuable strategies for cardiometabolic risk reduction, CR was associated with greater weight loss and more favourable improvements in body composition than treatment with liraglutide alone. Differences in the response to each of these interventions enables patients to be stratified to the most optimal intervention for their personal risk factors.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Inibidores da Dipeptidil Peptidase IV , Estado Pré-Diabético , Humanos , Adulto , Liraglutida/uso terapêutico , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Estado Pré-Diabético/tratamento farmacológico , Estado Pré-Diabético/complicações , Restrição Calórica , Apetite , Diabetes Mellitus Tipo 2/complicações , Hipoglicemiantes/efeitos adversos , Fosfato de Sitagliptina/uso terapêutico , Obesidade/complicações , Obesidade/tratamento farmacológico , Obesidade/induzido quimicamente , Inibidores da Dipeptidil Peptidase IV/efeitos adversos , Peso Corporal , Ingestão de Alimentos , Distribuição da Gordura Corporal , Redução de Peso , Dipeptidil Peptidases e Tripeptidil Peptidases , Doenças Cardiovasculares/complicações
10.
Microb Ecol ; 86(3): 2149-2160, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37133496

RESUMO

Identifying the major forces driving variation in gut microbiomes enhances our understanding of how and why symbioses between hosts and microbes evolved. Gut prokaryotic community variation is often closely associated with host evolutionary and ecological variables. Whether these same factors drive variation in other microbial taxa occupying the animal gut remains largely untested. Here, we present a one-to-one comparison of gut prokaryotic (16S rRNA metabarcoding) and microeukaryotic (18S rRNA metabarcoding) community patterning among 12 species of wild lemurs. Lemurs were sampled from dry forests and rainforests of southeastern Madagascar and display a range of phylogenetic and ecological niche diversity. We found that while lemur gut prokaryotic community diversity and composition vary with host taxonomy, diet, and habitat, gut microeukaryotic communities have no detectable association with any of these factors. We conclude that gut microeukaryotic community composition is largely random, while gut prokaryotic communities are conserved among host species. It is likely that a greater proportion of gut microeukaryotic communities comprise taxa with commensal, transient, and/or parasitic symbioses compared with gut prokaryotes, many of which form long-term relationships with the host and perform important biological functions. Our study highlights the importance of greater specificity in microbiome research; the gut microbiome contains many "omes" (e.g., prokaryome, eukaryome), each comprising different microbial taxa shaped by unique selective pressures.


Assuntos
Lemur , Microbiota , Animais , Filogenia , RNA Ribossômico 16S/genética , Dieta/veterinária
11.
Am J Primatol ; 85(5): e23497, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37095739

RESUMO

The COVID-19 pandemic caused by the SARS-CoV-2 virus brought many primatology research programs and conservation efforts to a halt. After Madagascar closed its borders during March 2020, many on-site international project leaders and researchers returned to their home countries when their programs were delayed or canceled. Madagascar remained closed to travelers until November 2021, when it reopened to international flights. The 20-month absence of international researchers allowed many local Malagasy program staff, wildlife professionals, and community leaders to step into new leadership roles and responsibilities. Many programs that already had strong Malagasy leadership and meaningful collaborations with local communities flourished, while others either swiftly strengthened these attributes or faced challenges from pandemic-related travel restrictions. Here, we describe how the coronavirus pandemic events of 2020-2021 initiated long-overdue shifts in outdated models of internationally led primate research and education projects in communities living alongside primates at risk of extinction. We discuss the benefits and challenges of pandemic-induced changes within five primatological outreach projects, as well as how we can use these experiences to improve community-led environmental education and conservation awareness in the future.


Assuntos
COVID-19 , Animais , COVID-19/epidemiologia , COVID-19/prevenção & controle , Madagáscar , Pandemias/prevenção & controle , Fortalecimento Institucional , SARS-CoV-2 , Primatas
12.
J Hosp Palliat Nurs ; 25(2): 55-74, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36843048

RESUMO

The Hospice and Palliative Nursing Association established the triannual research agenda to ( a ) provide focus for researchers to conduct meaningful scientific and quality improvement initiatives and inform evidence-based practice, ( b ) guide organizational funding, and ( c ) illustrate to other stakeholders the importance of nursing research foci. HPNA Research Agendas are developed to give direction for future research to continue advancing expert care in serious illness and ensure equitable delivery of hospice and palliative care.


Assuntos
Cuidados Paliativos na Terminalidade da Vida , Enfermagem de Cuidados Paliativos na Terminalidade da Vida , Hospitais para Doentes Terminais , Enfermeiras e Enfermeiros , Humanos , Cuidados Paliativos
13.
Am J Primatol ; 85(5): e23477, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36760220

RESUMO

A total of 94% of lemur species are currently threatened with extinction and more than 17 species of giant lemur are already extinct. To help prevent the extinction of Madagascar's remaining lemurs, Dr. Patricia Wright initiated conservation programs in the Ranomafana region of southern Madagascar in the 1990s. These continued and expanded, and in 2003 were consolidated with Dr. Wright's research activities when Center ValBio ("CVB") was founded in 2003. CVB believes in the "One Health" approach in understanding the relationship between humans and the environment, and one of their core principles is that effective conservation is science-based. CVB's environmental education (EE) programs (discussed herein) operate in various primary schools surrounding Ranomafana national park (RNP). The all-Malagasy team consists of long-term conservation educators as well as young intern teachers, who together address the issues of valuing lemurs and the forests that they require to survive. In this paper, we will describe three of CVB's EE programs and evaluate their impact. The primary tool used to assess impact was an analysis of pre- and post -intervention test scores evaluated using a Kruskal-Wallis test. We show that these programs (1) are popular, (2) produce concrete outputs that can change rural villages, and (3) improve local knowledge on the importance of biodiversity and sustainable development.


Assuntos
Lemur , Lemuridae , Strepsirhini , Humanos , Animais , Parques Recreativos , Biodiversidade , Florestas , Madagáscar
14.
Nurs Educ Perspect ; 44(2): 82-86, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36800406

RESUMO

AIM: The purpose of this study was to examine active listening, self-awareness, and empathy and how they relate to changes in patient-centered care (PCC) in undergraduate nursing students. BACKGROUND: PCC is associated with better patient outcomes, but the level of PCC has been found to be low in nursing students. METHOD: This secondary analysis used baseline and follow-up data at two time points from 50 undergraduate nursing students. RESULTS: Changes in self-awareness were associated with changes in PCC directly (Follow-Up 1) or directly and indirectly through the effects on changes in empathy (Follow-Up 2), controlling for age, experience, and intervention. Changes in active listening were associated with changes in PCC only indirectly through the effect on changes in empathy only at Follow-Up 2. CONCLUSION: Changes in self-awareness and active listening need to be the first targets of interventions to improve PCC in undergraduate nursing students.


Assuntos
Bacharelado em Enfermagem , Estudantes de Enfermagem , Humanos , Assistência Centrada no Paciente , Empatia
15.
Folia Primatol (Basel) ; 94(4-6): 207-223, 2023 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38593416

RESUMO

Madagascar's high rates of endemism, paired with its escalating deforestation rates, has made it one of the most important conservation priorities on the planet. In southeastern Madagascar, the Corridor Forestier d'Ambositra Vondrozo (COFAV) is an unprotected rainforest corridor that sustains ∼15 species of lemurs, most of which are endangered. The COFAV connects many protected areas and is therefore essential for gene flow, dispersal, and the long-term sustainability of animal populations in the area. The corridor has not been surveyed extensively since the 1990s, and even so, only a fraction of the sites have been sampled multiple times. The goal of our study was to survey the COFAV, from Ranomafana National Park to the Mananara River, to provide updated species occurrences and ranges. Combining data across multiple teams using different inventorying methods, we surveyed a total area of 227 km2 throughout an eight-month period. We recorded every lemur occurrence (sighting or vocalization) and noted the species, date, time, group size, and GPS coordinates. We found 11 lemur species and one putative hybrid species. The geographic ranges for three species (Hapalemur aureus, H. griseus, Propithecus edwardsi) were larger than previously thought. The range of Varecia variegata should be shortened and adjusted accordingly, as the species appears transient (at best) in the northern parts of Ranomafana National Park and was not found south of the Ambohimahamasina/Ikongo region. This study provides updated geographic ranges for lemur species in the COFAV, important information for future censuses, species assessments, and conservation measures for future implementation.


Assuntos
Lemur , Lemuridae , Strepsirhini , Animais , Madagáscar , Floresta Úmida
17.
J Comp Physiol B ; 192(6): 701-711, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36056931

RESUMO

When amphibious fishes are on land, gill function is reduced or eliminated and the skin is hypothesized to act as a surrogate site of ionoregulation. Skin ionocytes are present in many fishes, particularly those with amphibious life histories. We used nine closely related killifishes spanning a range of amphibiousness to first test the hypothesis that amphibious killifishes have evolved constitutively increased skin ionocyte density to promote ionoregulation on land. We found that skin ionocyte densities were constitutively higher in five of seven amphibious species examined relative to exclusively water-breathing species when fish were prevented from leaving water, strongly supporting our hypothesis. Next, to examine the scope for plasticity, we tested the hypothesis that skin ionocyte density in amphibious fishes would respond plastically to air-exposure to promote ionoregulation in terrestrial environments. We found that air-exposure induced plasticity in skin ionocyte density only in the two species classified as highly amphibious, but not in moderately amphibious species. Specifically, skin ionocyte density significantly increased in Anablepsoides hartii (168%) and Kryptolebias marmoratus (37%) following a continuous air-exposure, and only in K. marmoratus (43%) following fluctuating air-exposure. Collectively, our data suggest that highly amphibious killifishes have evolved both increased skin ionocyte density as well as skin that is more responsive to air-exposure compared to exclusively water-breathing and less amphibious species. Our findings are consistent with the idea that gaining the capacity for cutaneous ionoregulation is a key evolutionary step that enables amphibious fishes to survive on land.


Assuntos
Fundulidae , Peixes Listrados , Adaptação Fisiológica , Animais , Peixes Listrados/fisiologia , Pele , Água
18.
Microorganisms ; 10(9)2022 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-36144385

RESUMO

Numerous in vitro studies highlight the role of quorum sensing in the pathogenicity and virulence of biofilms. This narrative review discusses general principles in quorum sensing, including Gram-positive and Gram-negative models and the influence of flow, before focusing on quorum sensing and quorum quenching in cariogenic and periodontopathic biofilms. In cariology, quorum sensing centres on the role of Streptococcus mutans, and to a lesser extent Candida albicans, while Fusobacterium nucleatum and the red complex pathogens form the basis of the majority of the quorum sensing research on periodontopathic biofilms. Recent research highlights developments in quorum quenching, also known as quorum sensing inhibition, as a potential antimicrobial tool to attenuate the pathogenicity of oral biofilms by the inhibition of bacterial signalling networks. Quorum quenchers may be synthetic or derived from plant or bacterial products, or human saliva. Furthermore, biofilm inhibition by coating quorum sensing inhibitors on dental implant surfaces provides another potential application of quorum quenching technologies in dentistry. While the body of predominantly in vitro research presented here is steadily growing, the clinical value of quorum sensing inhibitors against in vivo oral polymicrobial biofilms needs to be ascertained.

19.
J Exp Biol ; 225(19)2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-36148563

RESUMO

Major ecological transitions such as the invasion of land by aquatic vertebrates may be facilitated by positive feedback between habitat choice and phenotypic plasticity. We used the amphibious fish Kryptolebias marmoratus to test the hypothesis that aquatic hypoxia, emergence behaviour and respiratory plasticity create this type of positive feedback loop that causes fish to spend increasing amounts of time on land. Terrestrially acclimated fish were more sensitive to aquatic hypoxia (emergence at higher PO2) and were less hypoxia tolerant (shorter time to loss of equilibrium) relative to water-acclimated fish, which are necessary conditions for positive feedback. Next, we tested the prediction that exposure to aquatic hypoxia causes fish to emerge frequently, reduce gill surface area, and become less hypoxia tolerant. Indeed, fish exposed to severe aquatic hypoxia spent almost 50% of the time out of water and coverage of the gill lamellae by an inter-lamellar cell mass almost doubled. Fish exposed to aquatic hypoxia that could emerge from water were also more sensitive to subsequent acute aquatic hypoxia and were less hypoxia tolerant than normoxia-exposed controls. These results are opposite those of fish that cannot escape from aquatic hypoxia and presumably arise owing to plastic changes that occur during air exposure. Together, these results indicate that emergence behaviour begets further emergence behaviour, driven by gill remodelling which reduces aquatic respiratory function. This type of positive feedback may explain how amphibious behaviour has repeatedly evolved in fishes that occupy hypoxic aquatic habitats despite the associated challenges of life on land.


Assuntos
Ciprinodontiformes , Peixes , Animais , Retroalimentação , Hipóxia , Plásticos , Água
20.
J Exp Zool A Ecol Integr Physiol ; 337(7): 776-784, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35727120

RESUMO

Many fishes encounter periods of prolonged darkness within their lifetime, yet the consequences for the visual system are poorly understood. We used an amphibious fish (Kryptolebias marmoratus) that occupies dark terrestrial environments during seasonal droughts to test whether exposure to prolonged darkness diminishes visual performance owing to reduced optic tectum (OT) size and/or neurogenesis. We performed a 3-week acclimation with a 2 ×$\times $ 2 factorial design, in which fish were either acclimated to a 12 h:12 h or 0 h:24 h light:dark photoperiod in water or in air. We found that water-exposed fish had poorer visual acuity when acclimated to the dark, while air-acclimated fish had poorer visual acuity regardless of photoperiod. The ability of K. marmoratus to capture aerial prey from water followed a similar trend, suggesting that good vision is important for hunting effectively. Changes in visual acuity did not result from changes in OT size, but air-acclimated fish had 37% fewer proliferating cells in the OT than water-acclimated fish. As K. marmoratus are unable to eat on land, reducing cell proliferation in the OT may serve as a mechanism to reduce maintenance costs associated with the visual system. Overall, we suggest that prolonged darkness and air exposure can impair vision in K. marmoratus, and that changes in visual performance may be mediated, in part, by OT neurogenesis. More broadly, we show that plastic changes to the visual system of fishes can have potential consequences for organismal performance and fitness.


Assuntos
Ciprinodontiformes , Aclimatação/fisiologia , Animais , Ciprinodontiformes/fisiologia , Água
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