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1.
Artigo em Inglês | MEDLINE | ID: mdl-34574576

RESUMO

Thiourea is an established disruptor of thyroid hormone synthesis and is frequently used as an inhibitor of metamorphosis. The changes caused by thiourea can affect processes associated with the oxidative status of individuals (metabolic rate, the HPI axis, antioxidant system). We investigated the parameters of oxidative stress in crested newt (Triturus spp.) larvae during normal development in late larval stage 62 and newly metamorphosed individuals, and during thiourea-stimulated metamorphosis arrest in individuals exposed to low (0.05%) and high (0.1%) concentrations of thiourea. Both groups of crested newts exposed to thiourea retained their larval characteristics until the end of the experiment. The low activities of antioxidant enzymes and the high lipid peroxidation level pointed to increased oxidative stress in larvae at the beginning of stage 62 as compared to fully metamorphosed individuals. The activities of catalase (CAT) and glutathione-S-transferase (GST) and the concentration of sulfhydryl (SH) groups were significantly lower in larvae reared in aqueous solutions containing thiourea than in newly metamorphosed individuals. The high thiourea concentration (0.1%) affected the antioxidative parameters to the extent that oxidative damage could not be avoided, contrary to a lower concentration. Our results provide a first insight into the physiological adaptations of crested newts during normal development and simulated metamorphosis arrest.


Assuntos
Antitireóideos , Triturus , Animais , Larva , Estresse Oxidativo , Salamandridae
2.
Transl Vis Sci Technol ; 10(10): 4, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34383878

RESUMO

Purpose: To establish optical coherence tomography (OCT) as an in vivo imaging modality for investigating the process of newt lens regeneration. Methods: Spectral-domain OCT was employed for in vivo imaging of the newt lens regeneration process. A total of 37 newts were lentectomized and followed by OCT imaging over the course of 60 to 80 days. Histological images were obtained at several time points to compare with the corresponding OCT images. Volume measurements were also acquired. Results: OCT can identify the key features observed in corresponding histological images based on the scattering differences from various eye tissues, such as the cornea, intact and regenerated lens, and the iris. Lens volume measurements from three-dimensional OCT images showed that the regenerating lens size increased linearly until 60 days post-lentectomy. Conclusions: Using OCT imaging, we were able to track the entire process of newt lens regeneration in vivo for the first time. Three-dimensional OCT images allowed us to volumetrically quantify and visualize the dynamic spatial relationships between tissues during the regeneration process. Our results establish OCT as an in vivo imaging modality to track/analyze the entire lens regeneration process from the same animal. Translational Relevance: Lens regeneration in newts represents a unique example of vertebrate tissue plasticity. Investigating the cellular and morphological events that govern this extraordinary process in vivo will advance our understanding and shed light on developing new therapies to treat blinding disorders in higher vertebrates.


Assuntos
Cristalino , Salamandridae , Animais , Iris , Cristalino/diagnóstico por imagem , Regeneração , Tomografia de Coerência Óptica
3.
Sci Rep ; 11(1): 14743, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34285310

RESUMO

Caudata is an order of amphibians with great variation in genome size, which can reach enormous dimensions in salamanders. In this work, we analysed the activity of transposable elements (TEs) in the transcriptomes obtained from female and male gonads of the Chinese fire-bellied newt, Cynops orientalis, a species with a genome about 12-fold larger than the human genome. We also compared these data with genomes of two basal sarcopterygians, coelacanth and lungfish. In the newt our findings highlighted a major impact of non-LTR retroelements and a greater total TE activity compared to the lungfish Protopterus annectens, an organism also characterized by a giant genome. This difference in TE activity might be due to the presence of young copies in newt in agreement also with the increase in the genome size, an event that occurred independently and later than lungfish. Moreover, the activity of 33 target genes encoding proteins involved in the TE host silencing mechanisms, such as Ago/Piwi and NuRD complex, was evaluated and compared between the three species analysed. These data revealed high transcriptional levels of the target genes in both newt and lungfish and confirmed the activity of NuRD complex genes in adults. Finally, phylogenetic analyses performed on PRDM9 and TRIM28 allowed increasing knowledge about the evolution of these two key genes of the NuRD complex silencing mechanism in vertebrates. Our results confirmed that the gigantism of the newt genomes may be attributed to the activity and accumulation of TEs.


Assuntos
Elementos de DNA Transponíveis/genética , Inativação Gênica , Genoma , Salamandridae/genética , Proteínas de Anfíbios/classificação , Proteínas de Anfíbios/genética , Animais , Evolução Molecular , Feminino , Gônadas/metabolismo , Histona-Lisina N-Metiltransferase/classificação , Histona-Lisina N-Metiltransferase/genética , Masculino , Filogenia , Salamandridae/metabolismo , Proteína 28 com Motivo Tripartido/classificação , Proteína 28 com Motivo Tripartido/genética , Urodelos/genética
4.
Zootaxa ; 4985(1): 136, 2021 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-34186673

RESUMO

Four new water mite species of the genus Hygrobates, subgenus Lurchibates (Acari, Hydrachnidia, Hygrobatidae) are described. Hygrobates (Lurchibates) macrochela sp. nov. Goldschmidt, Nishikawa Shimano is described in male and female; Hygrobates (Lurchibates) malosimilis sp. nov. Goldschmidt, Nishikawa Shimano is described in male, both new water mite species were collected from newts of the species Pachytriton inexpectatus Nishikawa, Jiang, Matsui Mo, 2011; Hygrobates (Lurchibates) incognitus sp. nov. Goldschmidt, Nishikawa Shimano is described in female collected from newts of the species Paramesotriton guangxiensis (Huang, Tang and Tang, 1983); Hygrobates (Lurchibates) fragmentarius sp. nov. Goldschmidt, Nishikawa Shimano is described in a single severely fragmented specimen (sex could not be determined) collected from a newt of the species Paramesotriton yunwuensis Wu, Jiang, and Hanken, 2010. Principal differences between the subgenus Lurchibates and the nominal subgenus Hygrobates s. str. are illustrated and discussed as well as the sexual dimorphism of Lurchibates. Morphometric analyses confirmed the morphological differences of ten out of the eleven so far described species (H. (L.) fragmentarius could not be included in the analysis); two morphological groups became evident mainly based upon the shape of the anterior coxae. These analyses as well provide an idea of possible phylogenetic relationships among the species. A key to all currently known species of the subgenus Lurchibates is given. So far the subgenus is restricted to SE-Asia, a map showing the distribution of all species is presented.


Assuntos
Ácaros/classificação , Salamandridae/parasitologia , Distribuição Animal , Animais , Ásia Sudeste , Feminino , Masculino , Ácaros/patogenicidade , Filogenia , Água
5.
J Exp Biol ; 224(13)2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34114002

RESUMO

Newts can use spatial variation in the magnetic field (MF) to derive geographic position, but it is unclear how they detect the 'spatial signal', which, over the distances that newts move in a day, is an order of magnitude lower than temporal variation in the MF. Previous work has shown that newts take map readings using their light-dependent magnetic compass to align a magnetite-based 'map detector' relative to the MF. In this study, time of day, location and light exposure (required by the magnetic compass) were varied to determine when newts obtain map information. Newts were displaced from breeding ponds without access to route-based cues to sites where they were held and/or tested under diffuse natural illumination. We found that: (1) newts held overnight at the testing site exhibited accurate homing orientation, but not if transported to the testing site on the day of testing; (2) newts held overnight under diffuse lighting at a 'false testing site' and then tested at a site located in a different direction from their home pond oriented in the home direction from the holding site, not from the site where they were tested; and (3) newts held overnight in total darkness (except for light exposure for specific periods) only exhibited homing orientation the following day if exposed to diffuse illumination during the preceding evening twilight in the ambient MF. These findings demonstrate that, to determine the home direction, newts require access to light and the ambient MF during evening twilight when temporal variation in the MF is minimal.


Assuntos
Magnetismo , Salamandridae , Animais , Campos Magnéticos , Orientação , Triturus
7.
Toxicon ; 198: 32-35, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-33933520

RESUMO

Tetrodotoxin (TTX) contents of wild-caught Chinese red-bellied newts, Cynops orientalis, and their offspring captive-reared from eggs to metamorphosed juveniles, were analysed using post-column LC-fluorescent detection (LC-FLD) and high resolution hydrophilic interaction liquid chromatography/mass spectrometry (HR-HILIC-LC/MS). TTX was detected in the parent newts and their eggs, but not in the larvae and juveniles raised under artificial condition over 20 months. However, juveniles reared in the presence of their parents, contained TTX-concentrations up to 8.05 µg/g. The origin of TTX may be implied from a close connection between the parents and their offspring.


Assuntos
Salamandridae , Animais , Cromatografia Líquida , Larva , Espectrometria de Massas , Tetrodotoxina/análise , Tetrodotoxina/toxicidade
8.
Org Lett ; 23(9): 3513-3517, 2021 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-33830775

RESUMO

The biosynthesis of the potent neurotoxin tetrodotoxin (TTX, 1) is still unresolved. We used MS-guided screening and nuclear magnetic resonance analyses including long-range HSQMBC to characterize two novel skeletal tricyclic guanidino compounds, Tgr-288 (2a and 2b) and Tgr-210 (3), from the TTX-bearing newt, Taricha granulosa. The presence of these compounds in toxic newts is congruent with a previously proposed pathway for TTX biosynthesis in terrestrial organisms that includes a monoterpene precursor and the production of structurally diversified guanidino compounds.


Assuntos
Guanidina/química , Monoterpenos/química , Salamandridae/metabolismo , Tetrodotoxina/química , Animais , Guanidina/análogos & derivados , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Tetrodotoxina/biossíntese
9.
J Therm Biol ; 97: 102896, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33863452

RESUMO

Tonic immobility (TI) is an important antipredator response employed by prey in the last stages of a predation sequence. Evolution by natural selection assumes consistent individual variation (repeatability) in this trait. In ectotherms, which experience variable body temperatures, TI should be repeatable over a thermal gradient to be targeted by natural selection; however, information on thermal repeatability of this trait is missing. We examined thermal repeatability of TI in juveniles of two sympatric amphibians, smooth (Lissotriton vulgaris) and alpine (Ichthyosaura alpestris) newts. Both species showed disparate TI responses to body temperature variation (13-28 °C). While the proportion of TI response was repeatable in both taxa, it increased with body temperature in alpine newts but was temperature independent in smooth newts. Duration of TI decreased with body temperature in both taxa but was only repeatable in smooth newts. Our results suggest that a warming climate may affect population dynamics of sympatric ectotherms through asymmetry in thermal reaction norms for antipredator responses.


Assuntos
Temperatura Corporal , Resposta de Imobilidade Tônica , Salamandridae/fisiologia , Temperatura , Animais , Mudança Climática , Modelos Biológicos , Simpatria
10.
Genes (Basel) ; 12(2)2021 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-33573315

RESUMO

c-Fos is an immediate-early gene that modulates cellular responses to a wide variety of stimuli and also plays an important role in tissue regeneration. However, the sequence and functions of c-Fos are still poorly understood in newts. This study describes the molecular cloning and characterization of the c-Fos gene (Co-c-Fos) of the Chinese fire-bellied newt, Cynops orientalis. The full-length Co-c-Fos cDNA sequence consists of a 1290 bp coding sequence that encoded 429 amino acids. The alignment and phylogenetic analyses reveal that the amino acid sequence of Co-c-Fos shared a conserved basic leucine zipper domain, including a nuclear localization sequence and a leucine heptad repeat. The Co-c-Fos mRNA is widely expressed in various tissues and is highly and uniformly expressed along the newt limb. After limb amputation, the expression of Co-c-Fos mRNA was immediately upregulated, but rapidly declined. However, the significant upregulation of Co-c-Fos protein expression was sustained for 24 h, overlapping with the wound healing stage of C. orientalis limb regeneration. To investigate if Co-c-Fos participate in newt wound healing, a skin wound healing model is employed. The results show that the treatment of T-5224, a selective c-Fos inhibitor, could largely impair the healing process of newt's skin wound, as well as the injury-induced matrix metalloproteinase-3 upregulation, which is fundamental to wound epithelium formation. These data suggest that Co-c-Fos might participate in wound healing by modulating the expression of its potential target gene matrix metalloproteinase-3. Our study provides important insights into mechanisms that are responsible for the initiation of newt limb regeneration.


Assuntos
Filogenia , Proteínas Proto-Oncogênicas c-fos/genética , Urodelos/genética , Sequência de Aminoácidos/genética , Animais , Clonagem Molecular , DNA Complementar/genética , Regulação da Expressão Gênica/genética , RNA Mensageiro/genética , Salamandridae/genética
11.
Ecotoxicol Environ Saf ; 208: 111731, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396062

RESUMO

Cadmium (Cd) is an environmental toxicant and a nonessential metal. Cd can attack a wide range of organs, such as the liver, kidney, lung, ovary, testis, brain, and muscle in vertebrates. Among these organs, the testis might be the most sensitive organ to Cd toxicity. Metallothionein (MT) is a cysteine-rich protein with a low molecular weight, that can bind with Cd and eliminate reactive oxygen species (ROSs). Hydrogen peroxide, which as a crucial type of ROS that is induced by Cd, can be eliminated by catalase (CAT) in the self-protection of cells and to realize Cd toxicity resistance. To investigate the functions of MT and CAT in the testis of Cynops orientalis, we cloned the full-length MT and CAT genes of C. orientalis for the first time. Immunofluorescence results demonstrated that MT and CAT were expressed in Sertoli cells and all spermatogenic cells in the testis of C. orientalis. The results of the ultrastructural damage assay demonstrated that there were various impairments, which included organelle vacuolization, abnormal chromatin distribution, and apoptotic bodies, in somatic cells that were exposed to Cd. However, the anomalies of spermatozoa were located mainly in the mid-piece and head, many of which showed severely impaired structures. The results demonstrated that MT and CAT expression had distinct patterns in response to various Cd concentrations: an increase in MT mRNA levels with elevated Cd levels and a persistent increase in CAT mRNA levels with elevated Cd levels. These results suggested that MT and CAT play roles in Cd toxicity resistance in the testis and that the expression of CAT may be a better biomarker than the expression of MT for assessing Cd pollution.


Assuntos
Cádmio/toxicidade , Catalase/metabolismo , Clonagem Molecular , Substâncias Perigosas/toxicidade , Metalotioneína/metabolismo , Salamandridae/fisiologia , Testículo/efeitos dos fármacos , Animais , Sequência de Bases , Humanos , Fígado/metabolismo , Masculino , RNA Mensageiro/metabolismo , Salamandridae/genética , Salamandridae/metabolismo , Células de Sertoli/metabolismo , Espermatozoides/metabolismo , Testículo/metabolismo
12.
Bioinformatics ; 37(10): 1475-1477, 2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-33010165

RESUMO

MOTIVATION: Visualization of cellular processes and pathways is a key recurring requirement for effective biological data analysis. There is a considerable need for sophisticated web-based pathway viewers and editors operating with widely accepted standard formats, using the latest visualization techniques and libraries. RESULTS: We developed a web-based tool named Newt for viewing, constructing and analyzing biological maps in standard formats such as SBGN, SBML and SIF. AVAILABILITY AND IMPLEMENTATION: Newt's source code is publicly available on GitHub and freely distributed under the GNU LGPL. Ample documentation on Newt can be found on http://newteditor.org and on YouTube.


Assuntos
Software , Biologia de Sistemas , Animais , Internet , Salamandridae , Transdução de Sinais
13.
Artigo em Inglês | MEDLINE | ID: mdl-33276133

RESUMO

Resting metabolic rate (RMR), i.e. spent energy necessary to maintain basic life functions, is a basic component of energy budget in ectotherms. The evolution of RMR through natural selection rests on the premise of its non-zero repeatability and heritability, i.e. consistent variation within individual lifetimes and resemblance between parents and their offspring, respectively. Joint estimates of RMR repeatability and heritability are missing in ectotherms, however, which precludes estimations of the evolutionary potential of this trait. We examined RMR repeatability and heritability in a long-lived ectotherm, the alpine newt (Ichthyosaura alpestris). Individual RMR was repeatable over both six-month (0.28 ±â€¯0.09 [SE]) and five-year (0.16 ±â€¯0.07) periods. While there was no resemblance between parent and offspring RMR (0.21 ±â€¯0.34), the trait showed similarity among offspring within families (broad-sense heritability; 0.25 ±â€¯0.09). Similar repeatability and broad-sense heritability values in parental and offspring generations, respectively, and non-conclusive narrow-sense heritability suggest the contribution of non-additive genetic factors to total phenotypic variance in this trait. We conclude that RMR evolutionary trajectories are shaped by other processes than natural selection in this long-lived ectotherm.


Assuntos
Metabolismo Basal/genética , Salamandridae/fisiologia , Animais , Reprodutibilidade dos Testes , Seleção Genética
14.
Artigo em Inglês | MEDLINE | ID: mdl-33022409

RESUMO

In nature, animals often face periods without food caused by seasonal fluctuations and/or prey scarcity. An organism's physiological response to imposed energetic limitations is followed by changes in mitochondrial functioning (adjustment of energy metabolism) and a reduction of non-essential processes. However, this energy-saving strategy can have its costs. In this study, we examined oxidative stress as one of the possible physiological costs of short-term, two-week-long food deprivation on developing amphibian larvae of the crested newts Triturus macedonicus and Triturus ivanbureschi and their hybrids. We investigated whether this exogenous factor additionally affected the oxidative status (fitness-related trait) of hybrid individuals. The fasting treatment led to lower growth and a lower body mass and body condition index of individuals. The results revealed that the antioxidant system (AOS) of food-deprived larvae could not cope in a proper manner with reactive oxygen species production under limited energy availability, leading to higher lipid oxidative damage. The lowest AOS response was observed for H2O2 scavenging parameters (catalase, glutathione peroxidase, and total glutathione), which together with the elevated activity of superoxide dismutase suggested increased H2O2 concentrations. Comparison between parental species and their hybrids showed that hybrid individuals suffered greater oxidative damage (as demonstrated by higher concentrations of lipid peroxides), indicating that they were more susceptible to fasting-induced oxidative stress. Overall, this study illustrates that: (i) an oxidative event is one of the costs amphibian larvae face during short-term periods of fasting, (ii) hybrids are less capable of dealing with this stressful condition, which can lower their chances of survival in a changing environment.


Assuntos
Jejum/fisiologia , Privação de Alimentos/fisiologia , Estresse Oxidativo/fisiologia , Salamandridae/metabolismo , Animais , Antioxidantes/metabolismo , Catalase/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Hibridização Genética , Peróxido de Hidrogênio/metabolismo , Larva/metabolismo , Peróxidos Lipídicos/metabolismo , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Salamandridae/classificação , Salamandridae/genética , Especificidade da Espécie , Fatores de Tempo
15.
Nat Commun ; 11(1): 5393, 2020 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-33106491

RESUMO

Wildlife diseases are contributing to the current Earth's sixth mass extinction; one disease, chytridiomycosis, has caused mass amphibian die-offs. While global spread of a hypervirulent lineage of the fungus Batrachochytrium dendrobatidis (BdGPL) causes unprecedented loss of vertebrate diversity by decimating amphibian populations, its impact on amphibian communities is highly variable across regions. Here, we combine field data with in vitro and in vivo trials that demonstrate the presence of a markedly diverse variety of low virulence isolates of BdGPL in northern European amphibian communities. Pre-exposure to some of these low virulence isolates protects against disease following subsequent exposure to highly virulent BdGPL in midwife toads (Alytes obstetricans) and alters infection dynamics of its sister species B. salamandrivorans in newts (Triturus marmoratus), but not in salamanders (Salamandra salamandra). The key role of pathogen virulence in the complex host-pathogen-environment interaction supports efforts to limit pathogen pollution in a globalized world.


Assuntos
Anuros/microbiologia , Quitridiomicetos/patogenicidade , Micoses/veterinária , Salamandridae/microbiologia , Urodelos/microbiologia , Animais , Quitridiomicetos/classificação , Quitridiomicetos/fisiologia , Micoses/microbiologia , Virulência
16.
Zootaxa ; 4768(2): zootaxa.4768.2.11, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33056531

RESUMO

Hygrobates salamandrarum Goldschmidt, Gerecke and Alberti, 2002 (Acari, Hydrachnidia, Hygrobatidae) is the first-known water mite parasitizing adult newts. After its description, three further species of newt-parasitizing mites were described and the subgenus Lurchibates Goldschmidt and Fu, 2011 was proposed for the group, now containing four newt-parasitizing mites. Until now, each water mite species parasitizes a different newt species (Table 1), suggesting possible mite-newt co-speciation. In order to test this hypothesis, we need an accurate taxonomy of both of the hosts and parasites. However, the taxonomy of those Asian newt genera known to be parasitized by Lurchibates mites has been substantially revised after the initial description of the H. salamandrarum. To account for these taxonomic changes, we here revise the host-parasite species list and amend the host species name as shown in Table 1.


Assuntos
Ácaros , Urodelos , Animais , Especificidade de Hospedeiro , Salamandridae , Água
17.
Zootaxa ; 4768(1): zootaxa.4768.1.3, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33056534

RESUMO

Males and females of three new water mite species of the genus Hygrobates Koch, 1837, subgenus Lurchibates Goldschmidt Fu, 2011 (Acari, Hydrachnidia, Hygrobatidae) are described. The diagnosis of the subgenus is extended based upon the new material. The new species were all just found on one newt species each: Hygrobates (Lurchibates) intermedius sp. nov. Goldschmidt, Nishikawa Shimano was collected from newts of the species Paramesotriton qixilingensis Yuan, Zhao, Jiang, Hou, He, Murphy Che, 2014 from Jiangxi Province, China; H. (L.) robustipalpis sp. nov. Goldschmidt, Nishikawa Shimano on Pachytriton inexpectatus Nishikawa, Jiang, Matsui Mo, 2011 from Guizhou Province, China and H. (L.) pilosus sp. nov. Goldschmidt, Nishikawa Shimano on Paramesotriton yunwuensis Wu, Jiang Hanken, 2010 found in a pet shop.


Assuntos
Ácaros , Animais , China , Feminino , Masculino , Salamandridae , Água
18.
J Nat Prod ; 83(9): 2706-2717, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32896120

RESUMO

The biosynthesis of tetrodotoxin (TTX, 1), a potent neurotoxin widely distributed in marine and terrestrial metazoans, remains unresolved. A significant issue has been identifying intermediates and shunt products associated with the biosynthetic pathway of TTX. We investigated TTX biosynthesis by screening and identifying new TTX-related compounds from Cynops ensicauda popei and Taricha granulosa. Mass spectrometry (MS)-guided screening identified two new N-hydroxy TTX analogues in newts: 1-hydroxy-8-epiTTX (2) and 1-hydroxy-8-epi-5,11-dideoxyTTX (3, previously reported as 1-hydroxy-5,11-dideoxyTTX). We prepared a new analogue, 8-epi-5,11-dideoxyTTX (4), from 3 via N-OH reduction and confirmed the presence of 4 in T. granulosa using hydrophilic interaction liquid chromatography (HILIC)-LCMS. The presence of 8-epi-type TTX analogues in both Cynops and Taricha supports a branched biosynthetic pathway of terrestrial TTX, which produces 6- and 8-epimers. In addition, new bicyclic guanidinium compounds Tgr-238 (5) and Tgr-240 (6) were identified as putative shunt products of our proposed TTX biosynthesis pathway. A structural analysis of Cep-228A (7), another bicyclic compound, was performed using NMR. Based on the structures of 5-7 and their analogues, we propose a model of the shunt and metabolic pathways of the terrestrial TTX biosynthesis.


Assuntos
Animais Venenosos , Guanidina/química , Salamandridae , Tetrodotoxina/análogos & derivados , Tetrodotoxina/química , Animais , Bactérias/efeitos dos fármacos , Compostos Bicíclicos com Pontes/química , Compostos Bicíclicos com Pontes/isolamento & purificação , Compostos Bicíclicos com Pontes/toxicidade , Cromatografia Líquida de Alta Pressão , Fungos/efeitos dos fármacos , Guanidina/isolamento & purificação , Guanidina/toxicidade , Espectrometria de Massas , Testes de Sensibilidade Microbiana , Estrutura Molecular , Bloqueadores dos Canais de Sódio/farmacologia , Tetrodotoxina/toxicidade
19.
J Exp Biol ; 223(Pt 21)2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-32968002

RESUMO

Intraoral food processing mechanisms are known for all major vertebrate groups, but the form and function of systems used to crush, grind or puncture food items can differ substantially between and within groups. Most vertebrates display flexible mechanisms of intraoral food processing with respect to different environmental conditions or food types. It has recently been shown that newts use cyclical loop-motions of the tongue to rasp prey against the palatal dentition. However, it remains unknown whether newts can adjust their food processing behavior in response to different food types or environmental conditions. Newts are interesting models for studying the functional adaptation to different conditions because of their unique and flexible lifestyle: they seasonally change between aquatic and terrestrial habitats, adapt their prey-capture mode to the respective environment, and consume diverse food types with different mechanical properties. Using X-ray high-speed recordings, anatomical investigations, behavioral analyses and mechanical property measurements, we tested the effects of the medium in which feeding occurs (water/air) and the food type (maggot, earthworm, cricket) on the processing behavior in Triturus carnifex We discovered that food processing, by contrast to prey capture, differed only slightly between aquatic and terrestrial habitats. However, newts adjusted the number of processing cycles to different prey types: while maggots were processed extensively, earthworm pieces were barely processed at all. We conclude that, in addition to food mechanical properties, sensory feedback such as smell and taste appear to induce flexible processing responses, while the medium in which feeding occurs appears to have less of an effect.


Assuntos
Comportamento Predatório , Triturus , Animais , Fenômenos Biomecânicos , Manipulação de Alimentos , Salamandridae
20.
J Morphol ; 281(11): 1391-1410, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32881082

RESUMO

Salamandrina perspicillata, from Northern and Central Italy, and Salamandrina terdigitata, from Southern Italy, represent a unique case of endemism among the amphibians of Europe. Some efforts were made to study the biology and ecology of these species, but only few studies focused on their comparative osteology. In particular, detailed descriptions of isolated skeletal elements and comparisons with other European urodeles are not available in literature hindering the identification of their fossils that testify for an ancient much broader range. The correct identification of fossil remains, mostly based on careful osteological descriptions, is fundamental to study the evolution of the range of this genus through time and the origin of the current endemic condition. This work is focused on the description of selected skeletal elements (occipito-otic complex, limb bones, atlas, trunk, sacral, caudosacral and caudal vertebrae) of dry-prepared skeletons and CT-scans of wet preserved specimens, which are the most common in the fossil record. We provide osteological comparison of Salamandrina with other genera of Europe, yielding diagnostic characters which allow the identification of fossils at a generic level. No significant differences between the two species S. perspicillata and S. terdigitata were found in the described skeletal elements, thus, the identification of skeletal elements at the species level is, at the moment, impossible.


Assuntos
Osso e Ossos/anatomia & histologia , Paleontologia , Salamandridae/anatomia & histologia , Pontos de Referência Anatômicos , Animais , Atlas como Assunto , Osso e Ossos/diagnóstico por imagem , Membro Anterior/anatomia & histologia , Membro Anterior/diagnóstico por imagem , Fósseis , Membro Posterior/anatomia & histologia , Membro Posterior/diagnóstico por imagem , Itália , Osteologia , Filogenia , Microtomografia por Raio-X
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