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International Journal of Molecular... May 2024The sodium-glucose co-transporter-2 (SGLT2) inhibitor dapagliflozin is increasingly used in the treatment of diabetes and heart failure. Dapagliflozin has been...
The sodium-glucose co-transporter-2 (SGLT2) inhibitor dapagliflozin is increasingly used in the treatment of diabetes and heart failure. Dapagliflozin has been associated with reduced incidence of atrial fibrillation (AF) in clinical trials. We hypothesized that the favorable antiarrhythmic outcome of dapagliflozin use may be caused in part by previously unrecognized effects on atrial repolarizing potassium (K) channels. This study was designed to assess direct pharmacological effects of dapagliflozin on cloned ion channels K11.1, K1.5, K4.3, K2.1, K2.1, K3.1, and K17.1, contributing to , , , , and K currents. Human channels coded by , , , , , , and were heterologously expressed in oocytes, and currents were recorded using the voltage clamp technique. Dapagliflozin (100 µM) reduced K11.1 and K1.5 currents, whereas K2.1, K2.1, and K17.1 currents were enhanced. The drug did not significantly affect peak current amplitudes of K4.3 or K3.1 K channels. Biophysical characterization did not reveal significant effects of dapagliflozin on current-voltage relationships of study channels. In conclusion, dapagliflozin exhibits direct functional interactions with human atrial K channels underlying , , , and currents. Substantial activation of K2.1 and K17.1 currents could contribute to the beneficial antiarrhythmic outcome associated with the drug. Indirect or chronic effects remain to be investigated in vivo.
Topics: Humans; Glucosides; Sodium-Glucose Transporter 2 Inhibitors; Benzhydryl Compounds; Animals; Xenopus laevis; Potassium Channels; Oocytes; Sodium-Glucose Transporter 2
PubMed: 38891889
DOI: 10.3390/ijms25115701 -
Animals : An Open Access Journal From... May 2024Chemical communication is an important mode of communication in the courtship and breeding processes of amphibians. In caudates, multiple components of sexual pheromones...
Chemical communication is an important mode of communication in the courtship and breeding processes of amphibians. In caudates, multiple components of sexual pheromones have been identified and functionally verified. One of these pheromone systems is plethodontid modulating factor (PMF). In anurans, the pheromone called amplexin was found in nuptial pads of ranids and was considered a member of the PMF system, yet its bio-function has not been tested. In this study, we obtained 18 amplexin transcript sequences from nuptial pads of (Amphibia, Ranidae) by transcriptome sequencing and found that the proteins translated by these transcripts are diversified, hydrophilic, and relatively stable. We also acquired a amplexin isoform with the highest expression level in the transcriptome analysis through the prokaryotic expression system. Using two different animal behavioral experimental settings, we have tested the bio-function of the recombinant PMF protein (rPMF) in 's reproduction and found that the rPMF does not attract females but shortens the duration of amplexus significantly. This is the first study to verify the function of the PMF pheromone in Anura, indicating the pervasiveness of chemical communication during breeding in amphibians.
PubMed: 38891597
DOI: 10.3390/ani14111550 -
Animals : An Open Access Journal From... May 2024Monogeneans are flatworm parasites that infest fish gills primarily but can also infect various other vertebrates, including amphibians, aquatic reptiles, mammals like... (Review)
Review
Monogeneans are flatworm parasites that infest fish gills primarily but can also infect various other vertebrates, including amphibians, aquatic reptiles, mammals like hippos, and occasionally invertebrates like copepods, isopods, and cephalopods. Despite their remarkable diversity, our knowledge of monogenean parasites in Peru remains significantly limited, resulting in substantial gaps in our comprehension of their taxonomic identities, host associations, and geographic distribution. To address these knowledge deficits, we present an extensively curated checklist of monogeneans associated with aquatic vertebrates in Peru. This comprehensive compilation is derived from meticulous literature surveys, the examination of specimens deposited in both international and national collections, and the inclusion of additional freshly collected specimens. The checklist offers a thorough repository of data encompassing the diversity, host associations, and geographical distribution of these parasites. Taxonomic discrepancies are addressed through a critical review of the existing literature, supplemented by the direct examination of specimens, including type or voucher specimens, deposited within scientific collections. Additionally, we provide data on the DNA sequences of individual taxa. The compiled list comprises records of 358 monogenean species, including 270 valid species and 88 taxa identified at the family or generic level, all reported across 145 host species in Peru. Predominantly, these parasitic species exhibit associations within fish, with 335 infecting teleosts and 20 affecting chondrichthyans. Three monogenean species have been documented as infecting amphibians, namely , sp. and . Among the monogeneans reported, 141 were found in marine environments and 214 in freshwater environments. The most diverse families were Dactylogyridae and Diplectanidae, comprising 217 and 24 species, respectively. The hosts that harbored the highest number of monogeneans were (with 23 species), followed by (13 spp.) and (11 spp.). We detected many species that do not have any material deposited in a scientific collection due to the loss or deactivation of the collection. These findings represent only a fraction of the potential diversity, considering the wide variety of aquatic vertebrate hosts inhabiting the tropical and subtropical regions of Peru.
PubMed: 38891589
DOI: 10.3390/ani14111542 -
Animals : An Open Access Journal From... May 2024The species-area relationship is important for understanding species diversity patterns at spatial scales, but few studies have examined the relationship using...
The species-area relationship is important for understanding species diversity patterns at spatial scales, but few studies have examined the relationship using environmental DNA (eDNA) techniques. We investigated amphibian diversity on 21 islands of the Zhoushan Archipelago and nearby mainland areas in China using the combination of eDNA metabarcoding and the traditional line transect method (TLTM) and identified the species-area relationship for amphibians on the islands. The mean detection probability of eDNA is 0.54, while the mean detection probability of TLTM is 0.24. The eDNA metabarcoding detected eight amphibian species on the islands and nine species in the mainland areas, compared with seven species on the islands and nine species in the mainland areas that were identified by TLTM. Amphibian richness on the islands increased with island area and habitat diversity. The species-area relationship for amphibians in the archipelago was formulated as the power function (S = 0.47A) or exponential function (S = 2.59 + 2.41 (logA)). Our results suggested that eDNA metabarcoding is more sensitive for the detection of amphibian species. The combined use of eDNA metabarcoding and the traditional line transect method may optimize the survey results for amphibians.
PubMed: 38891566
DOI: 10.3390/ani14111519 -
Molecular Phylogenetics and Evolution Jun 2024Unusually for oceanic islands, the granitic Seychelles host multiple lineages of endemic amphibians. This includes an ancient (likely ca. 60 million years) radiation of...
Unusually for oceanic islands, the granitic Seychelles host multiple lineages of endemic amphibians. This includes an ancient (likely ca. 60 million years) radiation of eight caecilian species, most of which occur on multiple islands.These caecilians have a complicated taxonomic history and their phylogenetic inter-species relationships have been difficult to resolve. Double-digest RAD sequencing (ddRADseq) has been applied extensively to phylogeography and increasingly to phylogenetics but its utility for resolving ancient divergences is less well established. To address this, we applied ddRADseq to generate a genome-wide SNP panel for phylogenomic analyses of the Seychelles caecilians, whose phylogeny has so far not been satisfactorily resolved with traditional DNA markers. Based on 129,154 SNPs, we resolved deep and shallow splits, with strong support. Our findings demonstrate the capability of genome-wide SNPs for evolutionary inference at multiple taxonomic levels and support the recently proposed synonymy of Grandisonia Taylor, 1968 with Hypogeophis Peters, 1879. We revealed three clades of Hypogeophis (large-, medium- and short-bodied) and identify a single origin of the diminutive, stocky-bodied and pointy-snouted phenotype.
PubMed: 38889862
DOI: 10.1016/j.ympev.2024.108130 -
Proceedings. Biological Sciences Jun 2024Biological invasions are among the threats to global biodiversity and social sustainability, especially on islands. Identifying the threshold of area at which non-native...
Biological invasions are among the threats to global biodiversity and social sustainability, especially on islands. Identifying the threshold of area at which non-native species begin to increase abruptly is crucial for early prevention strategies. The small-island effect (SIE) was proposed to quantify the nonlinear relationship between native species richness and area but has not yet been applied to non-native species and thus to predict the key breakpoints at which established non-native species start to increase rapidly. Based on an extensive global dataset, including 769 species of non-native birds, mammals, amphibians and reptiles established on 4277 islands across 54 archipelagos, we detected a high prevalence of SIEs across 66.7% of archipelagos. Approximately 50% of islands have reached the threshold area and thus may be undergoing a rapid increase in biological invasions. SIEs were more likely to occur in those archipelagos with more non-native species introduction events, more established historical non-native species, lower habitat diversity and larger archipelago area range. Our findings may have important implications not only for targeted surveillance of biological invasions on global islands but also for predicting the responses of both non-native and native species to ongoing habitat fragmentation under sustained land-use modification and climate change.
Topics: Introduced Species; Islands; Animals; Biodiversity; Conservation of Natural Resources; Ecosystem; Birds; Amphibians; Mammals; Reptiles
PubMed: 38889781
DOI: 10.1098/rspb.2024.0844 -
Comparative Biochemistry and... Jun 2024Ivermectin (IVM) is a broad-spectrum veterinary antiparasitic used worldwide in cattle breeding. The aim of this study was to evaluate the lethal effects of the active...
Ivermectin (IVM) is a broad-spectrum veterinary antiparasitic used worldwide in cattle breeding. The aim of this study was to evaluate the lethal effects of the active ingredient and a commercial formulation of IVM (1 % active ingredient) in the embryonic stage (S. 4-6) and larval stage (S. 25) of the South American amphibian Rhinella arenarum through chronic standardized bioassays. Also, behavior analysis and oxidative stress and cholinergic effects biomarkers were analyzed at 1, 10 and 100 μg IVM/L concentrations. For the embryonic stage, the active ingredient (96 h- LC: 15900 μg/L) was more toxic than the commercial formulation (96 h-LC: 51230 μg/L) during the acute period, while at chronic exposure the commercial formulation was more toxic (504 h-LC: 10.25 μg/L), compared to the active ingredient (504 h-LC: 312.80 μg/L). For the larval stage, in acute exposure, the active ingredient (96 h-LC: 800 μg/L) was more toxic than the commercial formulation (96 h-LC: 1550 μg/L). In the chronic exposure, the commercial formulation (504 h-LC: 77.33 μg/L) was more toxic than the active ingredient (504 h-LC: 195.25 μg/L). Overall, larvae exhibited greater sensitivity to both the active ingredient and the commercial formulation. However, during chronic exposure, embryos were more sensitive to the commercial formulation than larvae. The commercial formulation primarily induced oxidative stress, and both forms of the compound affected behavior and cholinergic effect biomarkers, even at low environmentally relevant concentrations (1 μg/L). These results highlight the potential impact of IVM on aquatic ecosystems.
PubMed: 38885750
DOI: 10.1016/j.cbpc.2024.109965 -
Proceedings of the National Academy of... Jun 2024An often-overlooked question of the biodiversity crisis is how natural hazards contribute to species extinction risk. To address this issue, we explored how four natural...
An often-overlooked question of the biodiversity crisis is how natural hazards contribute to species extinction risk. To address this issue, we explored how four natural hazards, earthquakes, hurricanes, tsunamis, and volcanoes, overlapped with the distribution ranges of amphibians, birds, mammals, and reptiles that have either narrow distributions or populations with few mature individuals. To assess which species are at risk from these natural hazards, we combined the frequency and magnitude of each natural hazard to estimate their impact. We considered species at risk if they overlapped with regions where any of the four natural hazards historically occurred (n = 3,722). Those species with at least a quarter of their range subjected to a high relative impact were considered at high risk (n = 2,001) of extinction due to natural hazards. In total, 834 reptiles, 617 amphibians, 302 birds, and 248 mammals were at high risk and they were mainly distributed on islands and in the tropics. Hurricanes (n = 983) and earthquakes (n = 868) affected most species, while tsunamis (n = 272), and volcanoes (n = 171) affected considerably fewer. The region with the highest number of species at high risk was the Pacific Ring of Fire, especially due to volcanoes, earthquakes, and tsunamis, while hurricane-related high-risk species were concentrated in the Caribbean Sea, Gulf of Mexico, and northwestern Pacific Ocean. Our study provides important information regarding the species at risk due to natural hazards and can help guide conservation attention and efforts to safeguard their survival.
Topics: Extinction, Biological; Animals; Biodiversity; Birds; Mammals; Reptiles; Earthquakes; Cyclonic Storms; Tsunamis; Amphibians; Volcanic Eruptions; Natural Disasters
PubMed: 38885390
DOI: 10.1073/pnas.2321068121 -
Parasitology Research Jun 2024Acanthocephalans, in their adult stage, are obligatory parasites of many types of vertebrates, including anuran amphibians. Their complex life cycle always involves an...
Acanthocephalans, in their adult stage, are obligatory parasites of many types of vertebrates, including anuran amphibians. Their complex life cycle always involves an arthropod intermediate host but may include non-obligatory strategies that could improve transmission success, such as paratenic infections. In paratenic hosts, these parasites are normally found loose in the body cavity or encysted in internal organs. Here, we present the first report of acanthocephalans found encysted under the skin of an amphibian (i.e., external to its body cavity). The specimen, a clay robber frog [Haddadus binotatus (Spix, 1824)], had been collected in an Atlantic Forest area in southeastern Brazil. Upon examination of the frog, we recovered two specimens of acanthocephalan (Order Echinorhynchida) encysted under the skin of its venter. Considering the host's relatively small size and its thin ventral musculature, we believe that the acanthocephalans may have accidentally trespassed the muscular tissue while attempting to encyst in the frog's internal body wall.
Topics: Animals; Acanthocephala; Brazil; Anura; Helminthiasis, Animal; Skin
PubMed: 38884663
DOI: 10.1007/s00436-024-08270-6 -
PeerJ 2024The Montseny brook newt (), a glacial relict endemic to a small, isolated massif in northeast Spain, is considered the only Critically Endangered urodele in Europe. Its...
The Montseny brook newt (), a glacial relict endemic to a small, isolated massif in northeast Spain, is considered the only Critically Endangered urodele in Europe. Its restricted range is divided by a deep valley that acts as an impassable barrier to dispersal, separating two isolated metapopulations (Western and Eastern) that correspond to independent lineages with different evolutionary trajectories, based on genetic and genomic data. Here, we address the ecological differentiation between lineages and discuss its potential effect on the phenotypic distinctness of each lineage. Based on multiple lines of evidence, we formally describe the Western Montseny brook newt as a new subspecies: Finally, our study underscores the importance of considering taxonomic progress in the conservation policies of endangered species, ensuring appropriate management and protection of the newly described taxa.
Topics: Spain; Animals; Salamandridae; Endangered Species; Phylogeny
PubMed: 38881865
DOI: 10.7717/peerj.17550