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1.
bioRxiv ; 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39314287

RESUMO

Parent-offspring interactions constitute the first contact of many newborns with their environment, priming community assembly of microbes through priority effects. Early exposure to microbes can have lasting influences on the assembly and functionality of the host's microbiota, leaving a life-long imprint on host health and disease. Studies of the role played by parental care in microbial acquisition have primarily focused on humans and hosts with agricultural relevance. Anuran vertebrates offer the opportunity to examine microbial community composition across life stages as a function of parental investment. In this study, we investigate vertical transmission of microbiota during parental care in a poison frog (Family Dendrobatidae), where fathers transport their offspring piggyback-style from terrestrial clutches to aquatic nurseries. We found that substantial bacterial colonization of the embryo begins after hatching from the vitelline envelope, emphasizing its potential role as microbial barrier during early development. Using a laboratory cross-foster experiment, we demonstrated that poison frogs performing tadpole transport serve as a source of skin microbes for tadpoles on their back. To study how transport impacts the microbial skin communities of tadpoles in an ecologically relevant setting, we sampled frogs and tadpoles of sympatric species that do or do not exhibit tadpole transport in their natural habitat. We found more diverse microbial communities associated with tadpoles of transporting species compared to a non-transporting frog. However, we detected no difference in the degree of similarity between adult and tadpole skin microbiotas, based on whether the frog species exhibits transporting behavior or not. Using a field experiment, we confirmed that tadpole transport can result in the persistent colonization of tadpoles by isolated microbial taxa associated with the caregiver's skin, albeit often at low abundance. This is the first study to describe vertical transmission of skin microbes in anuran amphibians, showing that offspring transport may serve as a mechanism for transmission of parental skin microbes. Overall, these findings provide a foundation for further research on how vertical transmission in this order impacts host-associated microbiota and physiology.

2.
Acta Vet Hung ; 72(3): 195-198, 2024 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-39172515

RESUMO

The ectoparasitic copepod Lernaea cyprinacea (anchor worm) has more than 100 host species among teleost fishes and affects cyprinids both in fish farms and natural waters. In addition, while L. cyprinacea infection in amphibians has been recorded in Asia, North and South America, there is no data available in the literature on their presence in Europe. In this study, we first reported L. cf. cyprinacea parasitising an anuran tadpole in Europe. Specimens of L. cf. cyprinacea were observed attached to a tadpole of the agile frog (Rana dalmatina), which was caught during fishing of crucian carp fingerlings (Carassius carassius) from a small fish pond in Hungary during the summer of 2012. The infected tadpole was collected from a rearing pond, where juvenile crucian carps were kept. The tadpole was inspected in the laboratory, and digital photos were taken. The parasites were found attached to the body-tail junction and to the leg of the tadpole (at Gosner stage 41). The parasite species was identified as L. cf. cyprinacea based on morphological traits.


Assuntos
Copépodes , Larva , Ranidae , Animais , Hungria/epidemiologia , Ranidae/parasitologia , Ectoparasitoses/veterinária , Ectoparasitoses/parasitologia , Ectoparasitoses/epidemiologia
3.
Adv Healthc Mater ; : e2400466, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39091049

RESUMO

Chemical topology provides a unique dimension for making therapeutic protein bioconjugates with native structure and intact function, yet the effects of topology remain elusive. Herein, the design, synthesis, and characterization of therapeutic protein bioconjugates in three topologies (i.e., tadpole, macrocycle, and figure-of-eight), are reported. The interferon α2b (IFN) and albumin binding domain (ABD) are selected as the model proteins for bioconjugation and proof-of-concept. The biosynthesis of these topological isoforms is accomplished via direct expression in cells using SpyTag-SpyCatcher chemistry and/or split-intein-mediated ligation for topology diversification. The corresponding topologies are proven with combined techniques of LC-MS, SDS-PAGE, and controlled proteolytic digestion. While the properties of these topological isoforms are similar in most cases, the figure-of-eight-shaped bioconjugate, f8-IFN-ABD, exhibits the best thermal stability and anti-aggregation properties along with prolonged half-life and enhanced tumor retention relative to the tadpole-shaped control, tadp-IFN-ABD, and the macrocyclic control, c-IFN-ABD, showcasing considerable topological effects. The work expands the topological diversity of proteins and demonstrates the potential advantages of leveraging chemical topology for functional benefits beyond multi-function integration in protein therapeutics.

4.
J Hazard Mater ; 479: 135649, 2024 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-39208625

RESUMO

The toxicity of microplastics (MPs) to aquatic animals is closely related to the presence and release kinetics of contained additives, as most plastic products contain various additives. However, the relationship between the occurrence and release of additives from MPs, and their individual or combined toxicity remains unclear. In this study, the nanoscale distribution and release of tetrabromobisphenol A (TBBPA, a common flame retardant with endocrine-disrupting effect) in polystyrene (PS) MPs, and the long-term (60 days) toxicity of TBBPA and MPs containing TBBPA (at doses of 0 %, 1 %, 10 %, w/w) to Xenopus tropicalis tadpoles were investigated. Exposure to 10 µg/L TBBPA alone was the most toxics, while the encapsulation of TBBPA in MPs significantly delayed its lethal toxicity to tadpoles by inhibiting the rapid and extensive release of TBBPA. PS MPs alone and MPs containing 10 % TBBPA exhibited delayed survival toxicity compared to TBBPA alone, whereas PS MPs containing 1 % TBBPA did not show this effect but inhibited growth. These findings suggest that chronic toxicity assessments should be based on long-term (months or even years) exposure experiments due to the encapsulation-controlled slow release of toxic additives.


Assuntos
Disruptores Endócrinos , Microplásticos , Bifenil Polibromatos , Xenopus , Xenopus/crescimento & desenvolvimento , Bifenil Polibromatos/análise , Bifenil Polibromatos/toxicidade , Larva/efeitos dos fármacos , Microplásticos/química , Microplásticos/toxicidade , Espectrometria de Massas em Tandem , Bioacumulação , Testes de Toxicidade , Disruptores Endócrinos/toxicidade
5.
Int J Mol Sci ; 25(13)2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-39000059

RESUMO

There is growing concern about the potential ecological risks posed by pharmaceutical residues in the aquatic environment. However, our understanding of the toxic effects of antiepileptic pharmaceuticals, such as carbamazepine (CBZ), on aquatic animal larvae is still limited. In this study, the tadpoles of the black-spotted pond frog (Pelophylax nigromaculatus) were exposed to environmentally relevant concentrations of CBZ (0.3 and 3.0 µg/L) for 30 days, and their growth, intestinal microbial composition, and metabolites were investigated to assess the potential toxic effects of CBZ in non-targeted aquatic organisms. Some tadpoles died during exposure, but there was no significant among-group difference in the survival and growth rates. CBZ exposure significantly altered the composition of tadpole intestinal microbiota. Relative abundances of some bacterial genera (e.g., Blautia, Prevotella, Bacillus, Microbacterium, etc.) decreased, while others (e.g., Paucibacter, etc.) increased in CBZ-exposed tadpoles. Interestingly, CBZ-induced alterations in some bacteria might not necessarily lead to adverse outcomes for animals. Meanwhile, small molecular intestinal metabolites related to energy metabolism, and antioxidant and anti-inflammatory activities were also altered after exposure. Taken together, environmentally relevant levels of CBZ might alter the metabolic and immune performances of amphibian larvae by modifying the abundance of some specific bacteria and the level of metabolites in their intestines, thereby potentially causing a long-term effect on their fitness.


Assuntos
Anticonvulsivantes , Carbamazepina , Microbioma Gastrointestinal , Larva , Poluentes Químicos da Água , Animais , Larva/efeitos dos fármacos , Carbamazepina/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Anticonvulsivantes/farmacologia , Poluentes Químicos da Água/toxicidade , Bactérias/efeitos dos fármacos
6.
J Parasitol ; 110(4): 311-338, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-39034606

RESUMO

The tadpole-dwelling pinworm, Gyrinicola batrachiensis (Walton, 1929) Adamson, 1981 was recognized as the sole representative of the genus across Canada and the United States. However, evaluation of the morphology of these parasites across their range revealed considerable morphological variability that suggested diagnosable morphotypes. These morphotypes were associated with different species of anurans, several of which occurred in sympatry. Herein we use an extensive geographic sampling across the United States to obtain the morphotypes, screen their genetic diversity, and analyze this information using an integrative approach. We reconstructed their phylogeny using nuclear ribosomal partial genes 18S and 28S, ITS1, 5.8S, and ITS2, as well as 5 mitochondrial genes generated with Next-Generation sequencing technology. This phylogeny reveals 3 well-resolved lineages, which upon the use of a statistical approach (bPTP [Bayesian implementation of the Poisson tree processes]) supports the delimitation of 4 distinct groups equivalent to species. These putative species groups were tested using morphological characteristics paired with a MANOVA and canonical variate analysis. Results suggest that at least 4 species of Gyrinicola are present within North America, resulting in the resurrection of G. armatus (Walton, 1933) and the description of 2 new species.


Assuntos
Teorema de Bayes , DNA de Helmintos , Variação Genética , Filogenia , Estados Unidos , Animais , DNA de Helmintos/química , Anuros/parasitologia , Oxyuroidea/classificação , Oxyuroidea/genética , Oxyuroidea/anatomia & histologia , RNA Ribossômico 28S/genética , DNA Espaçador Ribossômico/genética , DNA Mitocondrial/química , DNA Mitocondrial/genética
7.
Curr Zool ; 70(3): 332-342, 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39027420

RESUMO

Animals constantly need to evaluate available external and internal information to make appropriate decisions. Identifying, assessing, and acting on relevant cues in contexts such as mate choice, intra-sexual competition, and parental care is particularly important for optimizing individual reproductive success. Several factors can influence decision-making, such as external environmental cues and the animal's own internal state, yet, we have limited knowledge on how animals integrate available information. Here, we used an entire island population (57 males, 53 females, and 1,109 tadpoles) of the neotropical brilliant-thighed poison frog Allobates femoralis to investigate how 2 factors (olfactory cues and personality traits) influence the ability of males to find and use new resources for tadpole deposition. We experimentally manipulated the location of tadpole deposition sites and their associated olfactory cues, and repeatedly measured exploration and boldness in adult males. We further reconstructed tadpole deposition choices via inferred parent-offspring relationships of adult frogs and tadpoles deposited in our experimental pools using molecular parentage analysis. We found that the discovery and use of new rearing sites were heavily influenced by olfactory cues; however, we did not find an effect of the measured behavioral traits on resource discovery and use. We conclude that in highly dynamic environments such as tropical rainforests, reliable external cues likely take priority over personality traits, helping individuals to discover and make use of reproductive resources.

8.
Curr Zool ; 70(3): 332-342, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-39035761

RESUMO

Animals constantly need to evaluate available external and internal information to make appropriate decisions. Identifying, assessing, and acting on relevant cues in contexts such as mate choice, intra-sexual competition, and parental care is particularly important for optimizing individual reproductive success. Several factors can influence decision-making, such as external environmental cues and the animal's own internal state, yet, we have limited knowledge on how animals integrate available information. Here, we used an entire island population (57 males, 53 females, and 1,109 tadpoles) of the neotropical brilliant-thighed poison frog Allobates femoralis to investigate how 2 factors (olfactory cues and personality traits) influence the ability of males to find and use new resources for tadpole deposition. We experimentally manipulated the location of tadpole deposition sites and their associated olfactory cues, and repeatedly measured exploration and boldness in adult males. We further reconstructed tadpole deposition choices via inferred parent-offspring relationships of adult frogs and tadpoles deposited in our experimental pools using molecular parentage analysis. We found that the discovery and use of new rearing sites were heavily influenced by olfactory cues; however, we did not find an effect of the measured behavioral traits on resource discovery and use. We conclude that in highly dynamic environments such as tropical rainforests, reliable external cues likely take priority over personality traits, helping individuals to discover and make use of reproductive resources.

9.
J Econ Entomol ; 117(4): 1510-1517, 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-38824448

RESUMO

Rice seedlings of different stages of development were infested with tadpole shrimp (TPS, Triops longicaudatus [LeConte]), of different sizes in four experiments conducted in a lath house in Colusa, CA, during 2015 and 2016. Tadpole shrimp size was based on carapace length. Rice seedling stages were classified as S0 if no structures were present; S1 if only the coleoptile was present; S2 if the coleoptile and radicle were present; S3-I if the prophyll had emerged; S3-II if the first true leave had emerged but was not unfurled; and V1 if the first true leave was unfurled. Results showed that TPS of all sizes are capable of injuring rice and reducing seedling establishment, with larger TPS causing more seedling establishment reduction than medium or small TPS. The coleoptile, radicle, and roots were the structures most injured by TPS. During the S0 stage, TPS buried seeds, preventing their establishment. Seedling stages S1, S2, and S3-I were found to have the highest risk of injury by TPS, while seedling stage V1 had the lowest. Pearson's correlation between injured seedlings and the normalized number of established seedlings indicates that injury to the coleoptile, root, and radicle combined are the most important in preventing seedling establishment.


Assuntos
Oryza , Plântula , Animais , Oryza/crescimento & desenvolvimento , Plântula/crescimento & desenvolvimento , Decápodes/crescimento & desenvolvimento , Decápodes/fisiologia , Herbivoria , Larva/crescimento & desenvolvimento , Larva/fisiologia
10.
Plants (Basel) ; 13(11)2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38891367

RESUMO

Fractal evolution is apparently effective in selectively preserving environmentally resilient traits for more than 80 million years in Streptotrichaceae (Bryophyta). An analysis simulated maximum destruction of ancestral traits in that large lineage. The constraints enforced were the preservation of newest ancestral traits, and all immediate descendant species obtained different new traits. Maximum character state changes in ancestral traits were 16 percent of all possible traits in any one sub-lineage, or 73 percent total of the entire lineage. Results showed, however, that only four ancestral traits were permanently eliminated in any one lineage or sub-lineage. A lineage maintains maximum biodiversity of temporally and regionally survival-effective traits at minimum expense to resilience across a geologic time of 88 million years for the group studied. Similar processes generating an extant punctuated equilibrium as bursts of about four descendants per genus and one genus per 1-2 epochs are possible in other living groups given similar emergent processes. The mechanism is considered complexity-related, the lineage being a self-organized emergent phenomenon strongly maintained in the ecosphere by natural selection on fractal genera.

11.
Artigo em Inglês | MEDLINE | ID: mdl-38885749

RESUMO

Pesticides used in rice cultivation can cause negative health effects to non-target organisms representative of natural biodiversity. In this context, the present study aimed to investigate the occurrence of pesticides in surface waters from a river that flows in the middle of a rice farming-dominated area. We were also interested in evaluate biochemical and histological effects caused by exposure (16 d) to the lower and higher concentrations of the main found herbicide (bentazone, BTZ), insecticide (chlorantraniliprole, CTP) and fungicide (tebuconazole, TBZ), isolated or mixed, in Boana faber tadpoles. No significant differences were observed in the development of the animals. Tadpoles exposed to the herbicide BTZ showed higher hepatic levels of malondialdehyde (MDA). In animals exposed to CTP, MDA levels were lower than controls. Animals exposed to the fungicide TBZ showed higher hepatic activity of glutathione S-transferase and carboxylesterase (CbE), as well as higher levels of carbonyl proteins and MDA. Animals exposed to Mix showed higher activity in CbE and glucose-6-phosphate dehydrogenase activity in the liver, as well as higher levels of MDA. In the brain and muscle of tadpoles exposed to Mix, acetylcholinesterase activity was higher. Histological changes were also observed in pesticide-exposed animals, such as increased occurrence of melanomacrophages, inflammatory infiltrates and congestion. Our data evidences the contamination of natural aquatic environments by rice pesticides, and the adverse effects of main ones in B. faber tadpoles, which suggests the contribution of pesticides derived from rice cultivation to the degradation of local biodiversity health.


Assuntos
Biomarcadores , Larva , Fígado , Oryza , Poluentes Químicos da Água , ortoaminobenzoatos , Animais , Fígado/efeitos dos fármacos , Fígado/patologia , Fígado/metabolismo , Oryza/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Poluentes Químicos da Água/toxicidade , Biomarcadores/metabolismo , ortoaminobenzoatos/toxicidade , Praguicidas/toxicidade , Fungicidas Industriais/toxicidade , Agricultura , Triazóis/toxicidade , Herbicidas/toxicidade
12.
Artigo em Inglês | MEDLINE | ID: mdl-38714098

RESUMO

As amphibians undergo thyroid hormone (TH)-dependent metamorphosis from an aquatic tadpole to the terrestrial frog, their innate immune system must adapt to the new environment. Skin is a primary line of defense, yet this organ undergoes extensive remodelling during metamorphosis and how it responds to TH is poorly understood. Temperature modulation, which regulates metamorphic timing, is a unique way to uncover early TH-induced transcriptomic events. Metamorphosis of premetamorphic tadpoles is induced by exogenous TH administration at 24 °C but is paused at 5 °C. However, at 5 °C a "molecular memory" of TH exposure is retained that results in an accelerated metamorphosis upon shifting to 24 °C. We used RNA-sequencing to identify changes in Rana (Lithobates) catesbeiana back skin gene expression during natural and TH-induced metamorphosis. During natural metamorphosis, significant differential expression (DE) was observed in >6500 transcripts including classic TH-responsive transcripts (thrb and thibz), heat shock proteins, and innate immune system components: keratins, mucins, and antimicrobial peptides (AMPs). Premetamorphic tadpoles maintained at 5 °C showed 83 DE transcripts within 48 h after TH administration, including thibz which has previously been identified as a molecular memory component in other tissues. Over 3600 DE transcripts were detected in TH-treated tadpoles at 24 °C or when tadpoles held at 5 °C were shifted to 24 °C. Gene ontology (GO) terms related to transcription, RNA metabolic processes, and translation were enriched in both datasets and immune related GO terms were observed in the temperature-modulated experiment. Our findings have implications on survival as climate change affects amphibia worldwide.


Assuntos
Perfilação da Expressão Gênica , Imunidade Inata , Metamorfose Biológica , Pele , Temperatura , Hormônios Tireóideos , Transcriptoma , Animais , Metamorfose Biológica/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Pele/efeitos dos fármacos , Pele/metabolismo , Hormônios Tireóideos/metabolismo , Transcriptoma/efeitos dos fármacos , Rana catesbeiana/genética , Rana catesbeiana/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/genética , Larva/efeitos dos fármacos , Proteínas de Anfíbios/genética
13.
Dev Comp Immunol ; 156: 105178, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38599553

RESUMO

In the present study, using transgenic frogs that express GFP specifically in myeloid cells under the myeloperoxidase enhancer sequence, we found that myeloperoxidase-positive cells are localized in the liver cortex at the late tadpole stages. Immunohistochemical analysis revealed that myelopoiesis in the liver cortex became evident after st. 50 and reached its peak by st. 56. Transplantation experiments indicated that cells with a high density at the liver cortex were derived from the dorso-lateral plate tissue in the neurula embryo. Analysis of smear samples of the cells isolated from collagenase-treated liver tissues of the transgenic tadpoles indicated that myeloid cells were the major population of blood cells in the larval liver and that, in addition to myeloid colonies, erythroid colonies expanded in entire liver after metamorphosis. Cells that were purified from the livers of transgenic tadpoles according to the GFP expression exhibited the multi-lobed nuclei. The results of present study provide evidence that the liver cortex of the Xenopus tadpole is a major site of granulopoiesis.


Assuntos
Animais Geneticamente Modificados , Larva , Fígado , Células Mieloides , Xenopus laevis , Animais , Fígado/citologia , Mielopoese , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Fluorescência Verde/genética , Peroxidase/metabolismo , Metamorfose Biológica
14.
Regul Toxicol Pharmacol ; 149: 105619, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38614220

RESUMO

The Xenopus Eleutheroembryonic Thyroid Assay (XETA) was recently published as an OECD Test Guideline for detecting chemicals acting on the thyroid axis. However, the OECD validation did not cover all mechanisms that can potentially be detected by the XETA. This study was therefore initiated to investigate and consolidate the applicability domain of the XETA regarding the following mechanisms: thyroid hormone receptor (THR) agonism, sodium-iodide symporter (NIS) inhibition, thyroperoxidase (TPO) inhibition, deiodinase (DIO) inhibition, glucocorticoid receptor (GR) agonism, and uridine 5'-diphospho-glucuronosyltransferase (UDPGT) induction. In total, 22 chemicals identified as thyroid-active or -inactive in Amphibian Metamorphosis Assays (AMAs) were tested using the XETA OECD Test Guideline. The comparison showed that both assays are highly concordant in identifying chemicals with mechanisms of action related to THR agonism, DIO inhibition, and GR agonism. They also consistently identified the UDPGT inducers as thyroid inactive. NIS inhibition, investigated using sodium perchlorate, was not detected in the XETA. TPO inhibition requires further mechanistic investigations as the reference chemicals tested resulted in opposing response directions in the XETA and AMA. This study contributes refining the applicability domain of the XETA, thereby helping to clarify the conditions where it can be used as an ethical alternative to the AMA.


Assuntos
Bioensaio , Disruptores Endócrinos , Metamorfose Biológica , Simportadores , Glândula Tireoide , Animais , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/metabolismo , Metamorfose Biológica/efeitos dos fármacos , Bioensaio/métodos , Disruptores Endócrinos/toxicidade , Xenopus laevis , Receptores dos Hormônios Tireóideos/metabolismo , Receptores dos Hormônios Tireóideos/agonistas , Iodeto Peroxidase/metabolismo
15.
Environ Monit Assess ; 196(5): 465, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38647723

RESUMO

Seasonally astatic aquatic habitats are important ecologically, municipally, and agriculturally. Regulatory agencies and conservation organizations have developed various plans for protecting or constructing temporary wetlands, resulting in habitat monitoring requirements, particularly as relates to restoration and constructed habitats. Unfortunately, there has been no effort to develop a unified, consistent method for wetland biological monitoring. In Part I, we presented a quantifiable, replicable method for assessing seasonally astatic wetlands, which would allow for direct comparison between individual wetlands, wetland sites, and wetland types. Here in Part II, we apply the method and present the results from more than a decade of a data on two disparate sites that support California vernal pool habitats. These habitats include natural, restored, and constructed vernal pools. Our results demonstrate that the method we present yields reliable, statistically useful, and actionable data and provides a better method for assessing astatic wetland ecological health and the persistence of federally listed vernal pool crustaceans than other methods so far employed.


Assuntos
Ecossistema , Monitoramento Ambiental , Invertebrados , Estações do Ano , Áreas Alagadas , Monitoramento Ambiental/métodos , Animais , California , Conservação dos Recursos Naturais/métodos , Organismos Aquáticos , Monitoramento Biológico/métodos
16.
Dev Neurobiol ; 84(2): 59-73, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38439531

RESUMO

In contrast to other S100 protein members, the function of S100 calcium-binding protein Z (S100Z) remains largely uncharacterized. It is expressed in the olfactory epithelium of fish, and it is closely associated with the vomeronasal organ (VNO) in mammals. In this study, we analyzed the expression pattern of S100Z in the olfactory system of the anuran amphibian Xenopus laevis. Using immunohistochemistry in whole mount and slice preparations of the larval olfactory system, we found exclusive S100Z expression in a subpopulation of olfactory receptor neurons (ORNs) of the main olfactory epithelium (MOE). S100Z expression was not co-localized with TP63 and cytokeratin type II, ruling out basal cell and supporting cell identity. The distribution of S100Z-expressing ORNs was laterally biased, and their average number was significantly increased in the lateral half of the olfactory epithelium. The axons of S100Z-positive neurons projected exclusively into the lateral and intermediate glomerular clusters of the main olfactory bulb (OB). Even after metamorphic restructuring of the olfactory system, S100Z expression was restricted to a neuronal subpopulation of the MOE, which was then located in the newly formed middle cavity. An axonal projection into the ventro-lateral OB persisted also in postmetamorphic frogs. In summary, S100Z is exclusively associated with the main olfactory system in the amphibian Xenopus and not with the VNO as in mammals, despite the presence of a separate accessory olfactory system in both classes.


Assuntos
Neurônios Receptores Olfatórios , Proteínas S100 , Órgão Vomeronasal , Animais , Bulbo Olfatório/metabolismo , Mucosa Olfatória , Neurônios Receptores Olfatórios/metabolismo , Proteínas S100/metabolismo , Órgão Vomeronasal/metabolismo , Xenopus laevis/metabolismo
17.
Behav Ecol ; 35(3): arae014, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38545452

RESUMO

Living with a diverse array of predators provides a significant challenge for prey to learn and retain information about each predator they encounter. Consequently, some prey respond to novel predators because they have previous experience with a perceptually similar predator species, a phenomenon known as generalization of predator recognition. However, it remains unknown whether prey can generalize learned responses across ontogenetic stages of predators. Using wood frog tadpole (Lithobates sylvaticus) prey, we conducted two experiments to explore the extent of predator generalization of different life stages of two different predators: (1) predacious diving beetles (Dytiscus sp.) and (2) tiger salamanders (Ambystoma mavortium). In both experiments, we used chemical alarm cues (i.e., injured conspecific cues) to condition tadpoles to recognize the odor of either the larval or adult stage of the predator as risky. One day later, we tested tadpoles with either the larval or adult predator odor to determine whether they generalized their learned responses to the other life stages of the predator. Tadpoles generalized between larval and adult beetle odors but failed to generalize between larval and adult salamander odors. These results suggest that the odor of some predator species changes during metamorphosis to an extent that reduces their recognisability by prey. This "predator identity reset" increases the number of threats to which prey need to attend.

18.
Proc Biol Sci ; 291(2017): 20232850, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38412968

RESUMO

Microorganisms colonize the gastrointestinal tract of animals and establish symbiotic host-associated microbial communities that influence vertebrate physiology. More specifically, these gut microbial communities influence neurodevelopment through the microbiota-gut-brain (MGB) axis. We tested the hypothesis that larval amphibian neurodevelopment is affected by the aquatic microbial community present in their housing water. Newly hatched Northern Leopard Frog (Lithobates pipiens) tadpoles were raised in pond water that was unmanipulated (natural) or autoclaved. Tadpoles raised in autoclaved pond water had a gut microbiota with reduced bacterial diversity and altered community composition, had decreased behavioural responses to sensory stimuli, were larger in overall body mass, had relatively heavier brains and had altered brain shape when compared with tadpoles raised in natural pond water. Further, the diversity and composition of the gut microbiota were associated with tadpole behavioural responses and brain measurements. Our results suggest that aquatic microbial communities shape tadpole behaviour and brain development, providing strong support for the occurrence of the MGB axis in amphibians. Lastly, the dramatic role played by aquatic microbial communities on vertebrate neurodevelopment and behaviour should be considered in future wildlife conservation efforts.


Assuntos
Microbioma Gastrointestinal , Microbiota , Animais , Água , Larva/microbiologia , Anfíbios
19.
Ecotoxicol Environ Saf ; 273: 116119, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38382347

RESUMO

Heavy metals are released into the environment in increasing amounts from different natural and anthropogenic sources. Among them, cadmium contaminates aquatic habitats and represents a threat to Amphibians. To assess the risks of exposure to cadmium in the aquatic environment, we studied the survival rate of early tadpoles of Xenopus laevis under exposure to CdCl2 for 6 days in the concentration range between 0.15 and 150 µM of Cd2+. Tadpoles survived and reached stage 45 before feeding at all concentrations tested except 150 µM Cd2+, which significantly induced death. With an exposure of 15 µM Cd2+, tadpoles' mean body length decreased, heart rate increased, fastest swimming speed decreased, and distance traveled was greater compared to unexposed controls. Additionally, a witness of neuronal normal development, the neural cell adhesion molecules (NCAM) expression, was decreased. Moreover, this cell-surface glycoprotein exhibited higher polysialylation, a post-translational modification capable to reduce cell adhesion properties and to affect organ development. Our study highlights the effects of Cd2+ on a series of parameters including morphology, physiology, and behavior. They emphasize the deregulation of molecular NCAM suggesting this effector is an interesting biomarker to detect cadmic toxicity in early tadpoles.

20.
ACS Appl Mater Interfaces ; 16(12): 15533-15547, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38356451

RESUMO

Microrobots are of significant interest due to their smart transport capabilities, especially for precisely targeted delivery in dynamic environments (blood, cell membranes, tumor interstitial matrixes, blood-brain barrier, mucosa, and other body fluids). To perform a more complex micromanipulation in biological applications, it is highly desirable for microrobots to be stimulated with multiple stimuli rather than a single stimulus. Herein, the biodegradable and biocompatible smart micromotors with a Janus architecture consisting of PrecirolATO 5 and polycaprolactone compartments inspired by the anisotropic geometry of tadpoles and sperms are newly designed. These bioinspired micromotors combine the advantageous properties of polypyrrole nanoparticles (NPs), a high near-infrared light-absorbing agent with high photothermal conversion efficiency, and magnetic NPs, which respond to the magnetic field and exhibit multistimulus-responsive behavior. By combining both fields, we achieved an "on/off" propulsion mechanism that can enable us to overcome complex tasks and limitations in liquid environments and overcome the limitations encountered by single actuation applications. Moreover, the magnetic particles offer other functions such as removing organic pollutants via the Fenton reaction. Janus-structured motors provide a broad perspective not only for biosensing, optical detection, and on-chip separation applications but also for environmental water treatment due to the catalytic activities of multistimulus-responsive micromotors.


Assuntos
Nanopartículas , Polímeros , Pirróis , Membrana Celular , Lipídeos
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