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1.
Insect Mol Biol ; 28(6): 850-861, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31125161

RESUMO

Fatty acid synthase is a multifunctional enzyme involved in the formation of fatty acids. Despite the role of fatty acids in cell signalling and energy metabolism, and as precursors to pheromones and hydrocarbons that waterproof the cuticle, the insect fatty acid synthases have been scarcely studied. Here we perform the molecular characterization of three fatty acid synthase genes (fatty acid synthase RPRC000123, RPRC000269 and RPRC002909) in the Chagas disease vector, Rhodnius prolixus. Gene expression screening by reverse transcription quantitative PCR showed that RPRC000123 and RPRC002909 are expressed almost exclusively in the integument tissue whilst RPRC000269 is mostly expressed in the fat body and also in several body organs. Phylogenetic analysis, together with gene expression results, showed that RPRC000269, RPRC002909 and RPRC000123 are orthologues of Drosophila melanogaster fatty acid synthase 1 (FASN1), FASN2 and FASN3 genes, respectively. After RNA interference-mediated knockdown of RPRC000123, insects died immediately after moulting to the next developmental stage. However, mortality was prevented by placing the insects under saturated humidity conditions, suggesting that dehydration might play a role in the insects' death. Lipid analyses in RPRC000123-silenced insects showed reduced amounts of integument fatty acids and methyl-branched hydrocarbons, compared to controls. These data support an important role for FASN3 in the biosynthesis of the precursors to hydrocarbons that waterproof the insect cuticle.


Assuntos
Ácido Graxo Sintases/genética , Proteínas de Insetos/genética , Água/metabolismo , Animais , Ácido Graxo Sintases/metabolismo , Proteínas de Insetos/metabolismo , Tegumento Comum/fisiologia , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Filogenia , Rhodnius , Perda Insensível de Água
2.
Insect Biochem Mol Biol ; 108: 24-31, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30885802

RESUMO

Cuticle tanning occurs in insects immediately after hatching or molting. During this process, the cuticle becomes dark and rigid due to melanin deposition and protein crosslinking. In insects, different from mammals, melanin is synthesized mainly from dopamine, which is produced from DOPA by the enzyme DOPA decarboxylase. In this work, we report that the silencing of the RpAadc-2 gene, which encodes the putative Rhodnius prolixus DOPA decarboxylase enzyme, resulted in a reduction in nymph survival, with a high percentage of treated insects dying during the ecdysis process or in the expected ecdysis period. Those treated insects that could complete ecdysis presented a decrease in cuticle pigmentation and hardness after molting. In adult females, the knockdown of AADC-2 resulted in a reduction in the hatching of eggs; the nymphs that managed to hatch failed to tan the cuticle and were unable to feed. Despite the failure in cuticle tanning, knockdown of the AADC-2 did not increase the susceptibility to topically applied deltamethrin, a pyrethroid insecticide. Additionally, our results showed that the melanin synthesis pathway did not play a major role in the detoxification of the excess (potentially toxic) tyrosine from the diet, an essential trait for hematophagous arthropod survival after a blood meal.


Assuntos
Dopa Descarboxilase/fisiologia , Proteínas de Insetos/fisiologia , Tegumento Comum/fisiologia , Rhodnius/enzimologia , Rhodnius/crescimento & desenvolvimento , Animais , Dopa Descarboxilase/farmacologia , Feminino , Inativação Metabólica , Proteínas de Insetos/farmacologia , Inseticidas , Melaninas/metabolismo , Muda/fisiologia , Nitrilos , Pigmentação/fisiologia , Piretrinas , Reprodução , Rhodnius/genética , Tirosina/metabolismo
3.
Insect Biochem Mol Biol ; 108: 32-43, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30885803

RESUMO

The cuticular hydrocarbon (CHC) biosynthetic pathways branches off from the synthesis of fatty acids. Fatty acid elongases (ELOs) are enzymes catalyzing the synthesis of long-chain fatty acids and thereby contribute to the diversification of CHCs. Based on bioinformatics analyses we identified 20 ELO genes in the brown planthopper, Nilaparvata lugens. RNA interference against these genes demonstrated that 9 NlELO genes were essential for the survival of N. lugens nymphs and adults. Indeed, knockdown of NlELOs 1, 3, 4, 7, 8, 9, 10, 12 and 18 caused lethal phenotypes with a thin and wizened body and reduced lipids in the fat body. Surface analysis by scanning electron microscopy and CHC quantification indicated that knockdown of NlELOs 2, 3, 8 and 16 additionally resulted in a smooth body surface and a decrease in CHC amounts. Therefore, we speculate that long-chain CHCs are needed for CHC attachment to the cuticle surface. CHC deficiency, in turn, resulted in increased adhesion of water droplets and secreted honeydew to the animal surface and the inability of N. lugens to survive in paddy fields with varying humidity. Our present study provides an initial comprehensive analysis of ELO gene functions in an insect, and may serve to better understand the biology of CHCs.


Assuntos
/genética , Hemípteros/genética , Proteínas de Insetos/genética , Animais , Hemípteros/enzimologia , Hemípteros/metabolismo , Hidrocarbonetos/metabolismo , Proteínas de Insetos/metabolismo , Tegumento Comum , Metabolismo dos Lipídeos/genética , Família Multigênica , Interferência de RNA
4.
Mol Immunol ; 109: 108-115, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30927621

RESUMO

Baculovirus causes liquefaction of insect cuticle to enhance the dissemination of progeny virions away from the host cadavers for increasing viral transmission rates. Antheraea pernyi nucleopolyhedrovirus (ApNPV) infects A. pernyi larvae with circular pus blotches formed in cuticle in the early stage of liquefaction. To investigate the formation mechanism of those pus blotches, the transcriptome profile changes of the cuticles between ApNPV-infected and non-infected A. pernyi larvae were analyzed using RNA-Seq. The transcriptome was de novo assembled using the Trinity platform. Comparison of gene expression levels revealed that a total of 2990 and 4427 unigenes were up- and down-regulated respectively in ApNPV-infected cuticle, of which 2620 and 1903 differentially expressed genes (DEGs) could be enriched in different GO terms and KEGG pathways. In this study, we focused on chitin metabolism related DEGs, and screened 10 genes involved in chitin synthesis and degradation with down-regulated trends, indicating that the chitin metabolism pathway was inhibited by ApNPV infection, which may promote liquefaction of A. pernyi cuticle. Besides, we also identified a large number of DEGs involved in immune related pathways via KEGG analysis, indicating that intense immune responses occurred in A. pernyi cuticle. Our research findings will serve as a basis for further researching the molecular mechanisms underlying cuticle liquefaction of A. pernyi induced by ApNPV infection.


Assuntos
Tegumento Comum/virologia , Mariposas/genética , Mariposas/virologia , Análise de Sequência de RNA , Transcriptoma/genética , Animais , Quitinases/classificação , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Ontologia Genética , Anotação de Sequência Molecular , Filogenia , Reprodutibilidade dos Testes
5.
Insect Biochem Mol Biol ; 108: 61-70, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30904465

RESUMO

Insects are often regarded as the most successful group of animals in the terrestrial environment. Their success can be represented by their huge biomass and large impact on ecosystems. Among the factors suggested to be responsible for their success, we focus on the possibility that the cuticle might have affected the process of insects' evolution. The cuticle of insects, like that of other arthropods, is composed mainly of chitin and structural cuticle proteins. However, insects seem to have evolved a specific system for cuticle formation. Oxidation reaction of catecholamines catalyzed by a copper enzyme, laccase, is the key step in the metabolic pathway for hardening of the insect cuticle. Molecular phylogenetic analysis indicates that laccase functioning in cuticle sclerotization has evolved only in insects. In this review, we discuss a theory on how the insect-specific "laccase" function has been advantageous for establishing their current ecological position as terrestrial animals.


Assuntos
Insetos/enzimologia , Insetos/metabolismo , Tegumento Comum , Lacase/metabolismo , Animais , Quitina/metabolismo , Ecossistema , Evolução Molecular , Proteínas de Insetos/metabolismo , Insetos/classificação , Oxirredução , Filogenia
6.
PLoS One ; 14(3): e0213796, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30870522

RESUMO

Differences in the timing of exoskeleton melanization and sclerotization are evident when comparing eusocial and solitary bees. This cuticular maturation heterochrony may be associated with life style, considering that eusocial bees remain protected inside the nest for many days after emergence, while the solitary bees immediately start outside activities. To address this issue, we characterized gene expression using large-scale RNA sequencing (RNA-seq), and quantified cuticular hydrocarbon (CHC) through gas chromatography-mass spectrometry in comparative studies of the integument (cuticle plus its underlying epidermis) of two eusocial and a solitary bee species. In addition, we used transmission electron microscopy (TEM) for studying the developing cuticle of these and other three bee species also differing in life style. We found 13,200, 55,209 and 30,161 transcript types in the integument of the eusocial Apis mellifera and Frieseomelitta varia, and the solitary Centris analis, respectively. In general, structural cuticle proteins and chitin-related genes were upregulated in pharate-adults and newly-emerged bees whereas transcripts for odorant binding proteins, cytochrome P450 and antioxidant proteins were overrepresented in foragers. Consistent with our hypothesis, a distance correlation analysis based on the differentially expressed genes suggested delayed cuticle maturation in A. mellifera in comparison to the solitary bee. However, this was not confirmed in the comparison with F. varia. The expression profiles of 27 of 119 genes displaying functional attributes related to cuticle formation/differentiation were positively correlated between A. mellifera and F. varia, and negatively or non-correlated with C. analis, suggesting roles in cuticular maturation heterochrony. However, we also found transcript profiles positively correlated between each one of the eusocial species and C. analis. Gene co-expression networks greatly differed between the bee species, but we identified common gene interactions exclusively between the eusocial species. Except for F. varia, the TEM analysis is consistent with cuticle development timing adapted to the social or solitary life style. In support to our hypothesis, the absolute quantities of n-alkanes and unsaturated CHCs were significantly higher in foragers than in the earlier developmental phases of the eusocial bees, but did not discriminate newly-emerged from foragers in C. analis. By highlighting differences in integument gene expression, cuticle ultrastructure, and CHC profiles between eusocial and solitary bees, our data provided insights into the process of heterochronic cuticle maturation associated to the way of life.


Assuntos
Abelhas/genética , Epiderme/metabolismo , Epiderme/ultraestrutura , Hidrocarbonetos/análise , Proteínas de Insetos/genética , Tegumento Comum/fisiologia , Transcriptoma , Animais , Abelhas/crescimento & desenvolvimento , Feminino , Metamorfose Biológica
7.
J Therm Biol ; 80: 178-189, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30784484

RESUMO

Climatic factors, such as temperature variation, interfere with the survival of insects. To respond to these variations, insects have some specific characteristics. These include water content of the body, thickness of the lipid layer, as well as the qualitative and quantitative characteristics of cuticular chemical components. This study hypothesizes that different ant species respond to temperature changes in different ways and that such differences may be associated with cuticle hydrocarbons (CHCs) and fatty acids. As model ant species, Atta sexdens, Odontomachus bauri and Ectatomma brunneum were used for experimental analyses. Ants were submitted to a water bath for 5 h at different temperatures, and their CHCs and fatty acids were identified and quantified, followed by correlating these chemical compounds with temperature variations and the survival. Temperatures below 30 °C did not affect the survival of the three species. E. brunneum had a higher percentage of survival at temperatures above 30 °C. O. bauri was the most sensitive species with 100% mortality at 40 °C. Survival was found to be unrelated to any of the identified fatty acids. However, CHCs underwent significant quantitative and qualitative variation, as shown by an increased percentage of CHCs with longer chain length of linear alkanes at temperatures above 30 °C. These increase enables these ants to maintain the integrity of their cuticle and survive at temperatures above 30 °C. It can be concluded that the forager ants studied respond differently to temperature variation and that changes in the conformation of CHCs are in line with the ecological characteristics of the different studied species because, they vary in terms of diurnal/nocturnal foraging and types of environments foraged. Among the three species, E. brunneum foragers were found to be more active under adverse conditions and more tolerant to temperature variation with the correspondingly appropriate changes in CHCs composition.


Assuntos
Formigas/fisiologia , Hidrocarbonetos/análise , Tegumento Comum/fisiologia , Termotolerância , Animais , Ácidos Graxos/análise , Especificidade da Espécie , Temperatura Ambiente
8.
Pest Manag Sci ; 75(7): 1808-1818, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30740870

RESUMO

BACKGROUND: Vector control is the main intervention in malaria control and elimination strategies. However, the development of insecticide resistance is one of the major challenges for controlling malaria vectors. Anopheles arabiensis populations in Ethiopia showed resistance against both DDT and the pyrethroid deltamethrin. Although an L1014F target-site resistance mutation was present in the voltage gated sodium channel of investigated populations, the levels of resistance indicated the presence of additional resistance mechanisms. In this study, we used genome-wide transcriptome profiling by RNAseq to assess differentially expressed genes between three deltamethrin and DDT resistant An. arabiensis field populations - Asendabo, Chewaka and Tolay - and two susceptible strains - Sekoru and Mozambique. RESULTS: Both RNAseq analysis and RT-qPCR showed that a glutathione-S-transferase, gstd3, and a cytochrome P450 monooxygenase, cyp6p4, were significantly overexpressed in the group of resistant populations compared to the susceptible strains, suggesting that the enzymes they encode play a key role in metabolic resistance against deltamethrin or DDT. Furthermore, a gene ontology enrichment analysis showed that expression changes of cuticle related genes were strongly associated with insecticide resistance. Although this did not translate in increased thickness of the procuticle, a higher cuticular hydrocarbon content was observed in a resistant population. CONCLUSION: Our transcriptome sequencing of deltamethrin and DDT resistant An. arabiensis populations from Ethiopia suggests non-target site resistance mechanisms and paves the way for further investigation of the role of cuticle composition in insecticide resistance of malaria vectors. © 2019 Society of Chemical Industry.


Assuntos
Anopheles/genética , Anopheles/metabolismo , DDT/farmacologia , Resistência a Inseticidas/genética , Nitrilos/farmacologia , Piretrinas/farmacologia , Animais , Sistema Enzimático do Citocromo P-450/efeitos dos fármacos , Sistema Enzimático do Citocromo P-450/metabolismo , Etiópia , Perfilação da Expressão Gênica , Glutationa Transferase/efeitos dos fármacos , Glutationa Transferase/metabolismo , Inativação Metabólica/genética , Inseticidas/metabolismo , Inseticidas/farmacologia , Tegumento Comum/fisiologia , Mosquitos Vetores/efeitos dos fármacos
9.
Vet Parasitol ; 265: 38-47, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30638519

RESUMO

Using in vitro procedures to prepare newly excysted metacercariae and gut-penetrated juvenile Fasciola gigantica, the ultrastructural features of the tegumental syncytium and perikarya of these ephemeral stages in the host-invasion process were compared. The T0-type tegumental cells in newly excysted metacercariae are packed with stored T0 granules which, following transport to the surface membrane of the syncytium, discharge by exocytosis to maintain the glycocalyx. The T0 cells become depleted of T0 granules during the penetration process, shrink in size, and initiate autophagy in the cytoplasm to facilitate metamorphosis from a storage function to active biosynthesis. The novel products appear to include lysosomes which contribute to the autophagosomes, and T1 granules, necessary for maintenance of the glycocalyx and immunoprotection, as the invasion process continues into the host liver. Residual bodies, the end-products of autophagy, are eliminated from the apical membrane of the tegumental syncytium into the host-parasite interface. There they may present a transient source of parasite-derived molecules, including lysosomal cathepsin-type proteases, with potential for interaction with the host's immune system, and so might be exploited as targets for vaccinal and immunomodulatory studies.


Assuntos
Fasciola/ultraestrutura , Fasciolíase/veterinária , Fatores Imunológicos/química , Tegumento Comum/anatomia & histologia , Metacercárias/ultraestrutura , Vacinas/imunologia , Animais , Fasciolíase/prevenção & controle , Fatores Imunológicos/farmacologia
10.
Nat Ecol Evol ; 3(1): 24-30, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30568282

RESUMO

Pterosaurs were the first vertebrates to achieve true flapping flight, but in the absence of living representatives, many questions concerning their biology and lifestyle remain unresolved. Pycnofibres-the integumentary coverings of pterosaurs-are particularly enigmatic: although many reconstructions depict fur-like coverings composed of pycnofibres, their affinities and function are not fully understood. Here, we report the preservation in two anurognathid pterosaur specimens of morphologically diverse pycnofibres that show diagnostic features of feathers, including non-vaned grouped filaments and bilaterally branched filaments, hitherto considered unique to maniraptoran dinosaurs, and preserved melanosomes with diverse geometries. These findings could imply that feathers had deep evolutionary origins in ancestral archosaurs, or that these structures arose independently in pterosaurs. The presence of feather-like structures suggests that anurognathids, and potentially other pterosaurs, possessed a dense filamentous covering that probably functioned in thermoregulation, tactile sensing, signalling and aerodynamics.


Assuntos
Dinossauros/anatomia & histologia , Plumas/anatomia & histologia , Tegumento Comum/anatomia & histologia , Animais , Fósseis , Melanossomas
11.
Pest Manag Sci ; 75(7): 1951-1961, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30578597

RESUMO

BACKGROUND: Insect chitinases play a vital part in chitin degradation in exoskeletons and gut linings during the molting process, and therefore are considered potential targets for new insecticide designs or RNA interference (RNAi)-based pest management. Systematic functional analysis of chitinase genes has already been conducted in several insect pests, but not Plutella xylostella. RESULTS: In this study, 13 full-length chitinase transcripts were obtained in P. xylostella. Developmental and tissue-specific expression pattern analysis revealed that seven chitinase transcripts were periodically expressed during molting stage and mainly expressed in the integument or midgut, including PxCht3, PxCht5, PxCht6-2, PxCht7, PxCht8, PxCht10 and PxCht-h. RNAi-mediated knockdown of these specific expressed genes revealed that PxCht5 and PxCht10 were essential in larval molting, pupation and eclosion, and PxCht7 was indispensable only in eclosion. No significant effects were observed on insect survival or normal development when the rest chitinase transcripts were suppressed by RNAi. CONCLUSION: Our results indicated the function of P. xylostella chitinase family genes during the molting process, and may provide potential targets for RNAi-based management of P. xylostella. © 2018 Society of Chemical Industry.


Assuntos
Quitinases/genética , Mariposas/enzimologia , Mariposas/genética , Interferência de RNA , Animais , Trato Gastrointestinal/enzimologia , Trato Gastrointestinal/crescimento & desenvolvimento , Trato Gastrointestinal/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Tegumento Comum/crescimento & desenvolvimento , Muda/genética , Mariposas/crescimento & desenvolvimento
12.
J Morphol ; 279(11): 1548-1558, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30407645

RESUMO

Facultative air-breathing fish can exchange respiratory gases using an air-breathing organ (ABO), such as the oral cavity of the integument, during environmental hypoxia. The goby Gobionellus oceanicus inhabits areas subject to environmental hypoxia; however, its ABO is unknown. To investigate the respiratory potential of G. oceanicus, the gill and integument surface area, diffusion capacity, and their diffusion barrier thickness were measured. Our results show that although gill surface area is smaller than observed in other facultative air-breathing fish, but it has all features necessary to perform aquatic gas exchange. Additionally the integument of the palate has a short diffusion barrier thickness and a large calculated O2 -diffusion capacity suggesting that it functions as the ABO.


Assuntos
Tegumento Comum/anatomia & histologia , Tegumento Comum/fisiologia , Perciformes/anatomia & histologia , Perciformes/fisiologia , Respiração , Nadadeiras de Animais/anatomia & histologia , Animais , Brânquias/anatomia & histologia , Brânquias/fisiologia , Hipóxia
13.
Arch Insect Biochem Physiol ; 99(4): e21513, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30387887

RESUMO

In this study cuticular hydrocarbons (CHCs) were characterized from wings of individual unmated males of different Anastrepha ludens (Loew) mass-reared strains of different ages (3 and 19-day-old): (a) a standard mass-reared colony (control), (b) a genetic sexing strain, (c) a selected strain, (d) a hybrid strain, and (e) wild males. We found that the hydrocarbon profiles in all males included two n-alkanes, five monomethyl alkanes, and two alkenes. CHCs ranged from C26 to C31 . The most prominent peaks were 2-methyloctacosane (2-Me-C28), n-nonacosene (C29:1), 2-methyltriacontane (2-Me-C30), and n-hentriacontene (C31:1). Significant variations in the CHC amounts of the mass-reared strains were observed from Day 9 and thereafter. Comparison of CHCs using multivariate and canonical analyses across ages and among mass-reared strains and wild males revealed qualitative and quantitative differences. The relative amounts of C29:1 and 2-Me-C30 were significantly higher across age groups in the mass-reared strains than those in the wild males. In contrast, amounts of n-nonacosane (C29) significantly increased in wild males as they aged. Through statistical analyses, we inferred that CHC amounts vary with age. Wild males differed significantly from the mass-reared strains in the amount of C29, and the genetic sexing strain Tap-7 had significantly higher values for 2-methylhexacosane (2-Me-C26). In contrast the selected and control strain differed from the other strains in amounts of C29:1 and 2-Me-C30. We suggest that differential profiles in hydrocarbon composition among the strains may be mainly due to environmental pressures.


Assuntos
Envelhecimento/fisiologia , Hidrocarbonetos/metabolismo , Tegumento Comum/fisiologia , Tephritidae/fisiologia , Animais , Hidrocarbonetos/química , Masculino , Tephritidae/classificação , Tephritidae/crescimento & desenvolvimento
14.
Int J Mol Sci ; 19(10)2018 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-30322193

RESUMO

In insects, the integument provides mechanical support for the whole body and protects them from infections, physical and chemical injuries, and dehydration. Diversity in integument properties is often related to body shape, behavior, and survival rate. The stick (sk) silkworm is a spontaneous mutant with a stick-like larval body that is firm to the touch and, thus, less flexible. Analysis of the mechanical properties of the cuticles at day 3 of the fifth instar (L5D3) of sk larvae revealed higher storage modulus and lower loss tangent. Transcriptome sequencing identified a total of 19,969 transcripts that were expressed between wild-type Dazao and the sk mutant at L5D2, of which 11,596 transcripts were novel and detected in the integument. Differential expression analyses identified 710 upregulated genes and 1009 downregulated genes in the sk mutant. Gene Ontology (GO) enrichment analysis indicated that four chitin-binding peritrophin A domain genes and a chitinase gene were upregulated, whereas another four chitin-binding peritrophin A domain genes, a trehalase, and nine antimicrobial peptides were downregulated. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that two functional pathways, namely, fructose and mannose metabolism and tyrosine metabolism, were significantly enriched with differentially-expressed transcripts. This study provides a foundation for understanding the molecular mechanisms underlying the development of the stiff exoskeleton in the sk mutant.


Assuntos
Bombyx/anatomia & histologia , Perfilação da Expressão Gênica/métodos , Proteínas de Insetos/genética , Mutação , Animais , Bombyx/genética , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Tegumento Comum/anatomia & histologia , Fenótipo , Análise de Sequência de RNA
15.
J Evol Biol ; 31(12): 1959-1968, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30311708

RESUMO

The idea that the fitness value of body coloration may be affected by biochemically mediated trade-offs has received much research attention. For example, melanization is believed to interact with other fitness-related traits via competition for substrates, costs associated with the synthesis of melanin or pleiotropic effects of the involved genes. However, genetic correlations between coloration and fitness-related traits remain poorly understood. Here, we present a quantitative-genetic study of a coloration trait correlated to melanin-based cuticular darkness ('darkness', hereafter) in a geometrid moth, Ematurga atomaria. This species has considerable variation in larval appearance. We focus on correlations between larval darkness and fitness-related growth performance traits. Both a half-sib analysis and an 'animal model' approach revealed moderately high heritabilities of larval darkness and indices of growth performance. Heritability estimates of darkness derived from the animal model were, however, considerably higher than those based on the half-sib model suggesting that the determination of coloration includes genetic interactions and epigenetic effects. Importantly, on the host plant with the largest sample size, we found no evidence for either genetic or environmental correlations between darkness and growth parameters. On an alternative host plant, there was some indication of positive genetic and negative environmental correlation between these traits. This shows that respective relationships are environment-specific. Nevertheless, the overall pattern of weak and inconsistent correlations between larval coloration and growth parameters does not support universal trade-offs between these traits and suggests that physiological costs of producing colour patterns do not necessarily interfere with adaptive evolution of coloration.


Assuntos
Aptidão Genética , Mariposas/genética , Mariposas/fisiologia , Pigmentação/genética , Pigmentação/fisiologia , Animais , Tegumento Comum , Larva/genética , Larva/fisiologia
16.
PLoS One ; 13(10): e0205322, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30332676

RESUMO

The integumentary (i.e., skin) and gustatory systems both function to protect the human body and are a first point of contact with poisons and pathogens. These systems may share a similar protective mechanism because, as we show here, both human taste and skin cells express mRNA for bitter 'taste' receptors (TAS2Rs). We used gene-specific methods to measure mRNA from all known bitter receptor genes in adult human skin from freshly biopsied samples and from samples collected at autopsy from the Genotype-Tissue Expression project. Human skin expressed some but not all TAS2Rs, and for those that were expressed, the relative amounts differed markedly among individuals. For some TAS2Rs, mRNA abundance was related to presumed sun exposure based on the location from which the skin sample was collected (TAS2R14, TAS2R30, TAS2R42, and TAS2R60), sex (TAS2R3, TAS2R4, TAS2R8, TAS2R9, TAS2R14, and TAS2R60), and age (TAS2R5), although these effects were not large. These findings contribute to our understanding of extraoral expression of chemosensory receptors.


Assuntos
Receptores de Superfície Celular/genética , Receptores Acoplados a Proteínas-G/genética , Pele/metabolismo , Paladar/genética , Idoso , Idoso de 80 Anos ou mais , Feminino , Regulação da Expressão Gênica/genética , Genótipo , Células HEK293 , Humanos , Tegumento Comum , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/genética , Papilas Gustativas/metabolismo
17.
PLoS One ; 13(10): e0205656, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30335796

RESUMO

Studies on paleopathological alterations in fossil vertebrates, including damages caused by infections and ectoparasites, are important because they are potential sources of paleoecological information. Analyzing exoskeleton material (isolated osteoderms, carapace and caudal tube fragments) from fossil cingulates of the Brazilian Quaternary Megafauna, we identified damages that were attributed to attacks by fleas and dermic infections. The former were compatible with alterations produced by one species of flea of the genus Tunga, which generates well-delimited circular perforations with a patterned distribution along the carapace; the latter were attributable to pathogenic microorganisms, likely bacteria or fungi that removed the ornamentation of osteoderms and, in certain cases, generated craters or pittings. Certain bone alterations observed in this study represent the first record of flea attack and pitting in two species of large glyptodonts (Panochthus and Glyptotherium) and in a non-glyptodontid large cingulate (Pachyarmatherium) from the Quaternary of the Brazilian Intertropical Region. These new occurrences widen the geographic distribution of those diseases during the Cenozoic and provide more evidence for the co-evolutionary interaction between cingulates and parasites registered to date only for a small number of other extinct and extant species.


Assuntos
/parasitologia , Infestações por Pulgas/veterinária , Fósseis , Tegumento Comum/parasitologia , Animais , Evolução Biológica , Brasil , Infestações por Pulgas/parasitologia , Tegumento Comum/microbiologia , Paleopatologia , Filogenia
18.
J Exp Biol ; 221(Pt 22)2018 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-30224370

RESUMO

Carotenoids give color to conspicuous animal signals that are often the product of sexual selection. Knowledge of the mechanisms involved in carotenoid-based signaling is critical to understanding how these traits evolve. However, these mechanisms remain only partially understood. Carotenoids are usually viewed as scarce dietary antioxidants whose allocation to ornaments may trade off against health. This trade-off would ensure its reliability as a signal of individual quality. In the case of red (keto)carotenoids, the literature suggests that some species may show constraints in their uptake. Canthaxanthin is one of the most common ketocarotenoids in red ornaments of animals. It is often commercially used as a dietary supplement to obtain redder birds (e.g. poultry). We increased the dietary canthaxanthin levels in captive red-legged partridges (Alectoris rufa). This species shows red non-feathered parts mostly pigmented by another common ketocarotenoid: astaxanthin. We studied the impact on the uptake of carotenoids and vitamins and, finally, on coloration. We also tested the potential protective effect of canthaxanthin when exposing birds to a free radical generator (diquat). Canthaxanthin did not apparently protect birds from oxidative stress, but interfered with the absorption of yellow carotenoids (lutein and zeaxanthin). Zeaxanthin is a precursor of astaxanthin in enzymatic pathways, and their levels in tissues and eggs were lower in canthaxanthin-supplied birds. This led to lower astaxanthin levels in ornaments and paler coloration. As far as we know, this is the first report of a carotenoid supplementation decreasing animal coloration. The results have implications for understanding carotenoid-based signaling evolution, but also for improving husbandry/experimental procedures.


Assuntos
Cantaxantina/farmacologia , Cor , Codorniz/fisiologia , Xantofilas/metabolismo , Ração Animal/análise , Animais , Dieta/veterinária , Diquat/farmacologia , Feminino , Tegumento Comum/fisiologia , Masculino , Óvulo/química , Estresse Oxidativo
19.
J Evol Biol ; 31(12): 1772-1781, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30178526

RESUMO

Chemical traits are increasingly recognized as important cues used in mate choice. For example, the cuticular hydrocarbons (CHCs) of insects have been shown to influence mating success in a range of taxa. Less is known, however, about how CHCs are expressed in proportion to an individual's condition, and consequently whether CHCs can function as condition-dependent signals of quality. We investigated this question using the dung beetle, Onthophagus taurus. CHCs are subject to sexual selection in this species through mate choice. A dietary manipulation revealed condition dependence of CHC expression for both sexes: dietary restriction decreased overall CHC production and altered the composition of CHCs. Furthermore, CHC production was associated with a measure of condition in beetles fed a limited diet but not those fed ad libitum. These results implicate a resource cost to CHC production that is likely to result in trade-offs with other fitness components in this species, as these respond similarly to a dietary restriction. The CHC profiles showed sexual dimorphism: males produced more CHCs and the sexes differed in the blend of compounds they produced. There was evidence for a male dimorphism in the CHC profile, in line with the presence of the alternative reproductive tactics (minor sneaks and major fighters) in this species. However, rather than mimicking a female CHC profile, minor males differed more from females than major males. Our results suggest that CHCs are a costly trait in O. taurus that has the potential to act as a condition-dependent signal of quality.


Assuntos
Besouros/fisiologia , Dieta , Hidrocarbonetos/metabolismo , Preferência de Acasalamento Animal , Animais , Feminino , Tegumento Comum , Masculino , Fenótipo , Caracteres Sexuais
20.
Arq. Ciênc. Vet. Zool. UNIPAR (Online) ; 21(1): 9-12, Jan-Mar. 2018. tab
Artigo em Português | LILACS, VETINDEX | ID: biblio-915828

RESUMO

O objetivo desta pesquisa foi verificar a prevalência de dermatófitos em tegumento de bovinos e ovinos hígidos e a sua capacidade de transmissão e desenvolvimento da doença. Para isso, foram coletadas amostras de pelo e descamações de 90 bovinos e 90 ovinos hígidos. Essas amostras foram semeadas em meio DTM e ágar Sabouraud Dextrose enriquecido com extrato de levedura, tiamina, antibióticos (estreptomicina e cloranfenicol) e suplementado de cicloheximida, sendo essas incubadas a 35 oC por 10 dias. As culturas positivas foram avaliadas macro e microscopicamente e, os fungos foram identificados por métodos bioquímicos. Verificou-se que as espécies isoladas com maior frequência, nos bovinos, foram T. mentagrophytes e M. gypseum. Nos ovinos, foi constatada maior ocorrência do agente T. verrucosum, seguido por T. mentagrophytes e M. gypseum. Houve também isolamento de M. canis, porém, em um número reduzido de amostras. Assim, concluiu-se que o tegumento de bovinos e de ovinos hígidos apresentou incidência elevada de dermatófitos de diferentes espécies, em amostras coletadas durante o período chuvoso do ano. Por isso, em animais jovens ou naqueles submetidos a elevados níveis de estresse e, consequente queda da resposta imunológica, o risco de desenvolvimento da dermatofitose e da transmissão dos dermatófitos neste período são eminentes.(AU)


The purpose of this study was to determine the prevalence of dermatophytes in healthy cattle and sheep teguments, and their ability to transmit and develop diseases. Samples of fur and flaking from 90 healthy cattle and 90 healthy sheep were collected. These samples were plated on DTM medium and Sabouraud Dextrose agar supplemented with yeast extract, thiamine, antibiotics (streptomycin and chloramphenicol) enhanced with cycloheximide. They were then incubated at 35 °C for 10 days. Positive cultures were macroscopically and microscopically evaluated, and fungi were identified by biochemical methods. It was found that the most frequent species isolated in cattle were T. mentagrophytes and M. gypseum. In sheep, a higher occurrence of the agent T. verrucosum could be observed, followed by T. mentagrophytes and M. gypseum. There was also the isolation of M. canis, but in a small number of samples. Thus, it could be concluded that the tegument of healthy cattle and sheep showed high incidence of dermatophytes from different species in samples collected during the rainy season of the year. Therefore, in young animals, in those subjected to high levels of stress and consequent drop in immune response, there is eminent risk of developing dermatophytosis and transmission of dermatophytes in this period.(AU)


El objetivo de esta investigación ha sido verificar la prevalencia de dermatofitos en tegumento de bovinos y ovinos hígidos y su capacidad de transmisión y desarrollo de la enfermedad. Para ello, se recolectó muestras de pelo y descamaciones de 90 bovinos y 90 ovinos hígidos. Esas muestras fueron sembradas en medio DTM y agar Sabouraud Dextrosis enriquecida con extracto de levadura, tiamina, antibióticos (estreptomicina y cloranfenicol) y suplementado de cicloheximida, siendo esas incubadas a 35ºC durante 10 días. Los cultivos positivos fueron evaluados macro y microscópicamente y los hongos fueron identificados por métodos bioquímicos. Se verificó que las especies aisladas con mayor frecuencia, en los bovinos, fueron T. mentagrophytes y M. gypseum. En los ovinos, se constató mayor ocurrencia del agente T. verrucosum, seguido por T. mentagrophytes y M. gypseum. También hubo aislamiento de M. canis, sin embargo, en un número reducido de muestras. Así, se concluyó que el tegumento de bovinos y de ovinos hígidos presentó una elevada incidencia de dermatofitos de diferentes especies, en muestras recogidas durante el período lluvioso del año. Por lo tanto, en animales jóvenes o en aquellos sometidos a altos niveles de estrés y, consecuente caída de la respuesta inmunológica, el riesgo de desarrollo de la dermatofitosis y de la transmisión de los dermatofitos en este período son eminentes.(AU)


Assuntos
Animais , Bovinos , Bovinos/microbiologia , Ovinos/microbiologia , Arthrodermataceae/patogenicidade , Tegumento Comum
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