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Veterinary Dermatology Jun 2024A climbing mantella frog (Mantella laevigata) was presented with nodular thickened skin. Histological examination revealed dermal nodules composed of differentiated bone...
A climbing mantella frog (Mantella laevigata) was presented with nodular thickened skin. Histological examination revealed dermal nodules composed of differentiated bone consistent with miliary osteoma cutis, a non-neoplastic condition where bone is abnormally deposited within the skin. This is the first report of idiopathic osteoma cutis in an amphibian.
PubMed: 38938127
DOI: 10.1111/vde.13273 -
Scientific Data Jun 2024The ongoing biodiversity crisis is strongly threatening amphibians, mostly because of their peculiar physiology, their sensitivity to climate change and the spread of...
The ongoing biodiversity crisis is strongly threatening amphibians, mostly because of their peculiar physiology, their sensitivity to climate change and the spread of diseases. Effective monitoring involving assessments of pressure effects across time and estimation of population trends play a key role in mitigating amphibian decline. To improve implementation of standardized protocols and conservation efforts, we present here a dataset related to one of the amphibian genera whose onservation status is considered the most declining according to the IUCN. We report information on 66 populations of the endangered European cave salamanders, genus Speleomantes, that was collected through a standardized monitoring along a four-year period (2021-2024). Demographics data of the populations and fitness-related data of single individuals are reported. Furthermore, we include 3,836 high quality images of individuals that can allow to perform studies aiming to assess the phenotypic variability within the genus, and to perform long-term capture-mark-recaptured studies.
Topics: Animals; Urodela; Endangered Species; Conservation of Natural Resources; Europe; Biodiversity; Climate Change
PubMed: 38937493
DOI: 10.1038/s41597-024-03555-y -
Bulletin of Mathematical Biology Jun 2024We introduce a model that can be used for the description of the distribution of species when there is scarcity of data, based on our previous work (Ballesteros et al. J...
We introduce a model that can be used for the description of the distribution of species when there is scarcity of data, based on our previous work (Ballesteros et al. J Math Biol 85(4):31, 2022). We address challenges in modeling species that are seldom observed in nature, for example species included in The International Union for Conservation of Nature's Red List of Threatened Species (IUCN 2023). We introduce a general method and test it using a case study of a near threatened species of amphibians called Plectrohyla Guatemalensis (see IUCN 2023) in a region of the UNESCO natural reserve "Tacaná Volcano", in the border between Mexico and Guatemala. Since threatened species are difficult to find in nature, collected data can be extremely reduced. This produces a mathematical problem in the sense that the usual modeling in terms of Markov random fields representing individuals associated to locations in a grid generates artificial clusters around the observations, which are unreasonable. We propose a different approach in which our random variables describe yearly averages of expectation values of the number of individuals instead of individuals (and they take values on a compact interval). Our approach takes advantage of intuitive insights from environmental properties: in nature individuals are attracted or repulsed by specific features (Ballesteros et al. J Math Biol 85(4):31, 2022). Drawing inspiration from quantum mechanics, we incorporate quantum Hamiltonians into classical statistical mechanics (i.e. Gibbs measures or Markov random fields). The equilibrium between spreading and attractive/repulsive forces governs the behavior of the species, expressed through a global control problem involving an energy operator.
Topics: Animals; Endangered Species; Mathematical Concepts; Models, Biological; Mexico; Conservation of Natural Resources; Guatemala; Markov Chains; Population Density; Anura; Ecosystem; Animal Distribution; Population Dynamics
PubMed: 38935181
DOI: 10.1007/s11538-024-01315-y -
Developmental Dynamics : An Official... Jun 2024Vertebrate left-right symmetry breaking is preceded by formation of left-right organizer. In Amphibian, this structure is formed by gastrocoel roof plate, which emerges...
BACKGROUND
Vertebrate left-right symmetry breaking is preceded by formation of left-right organizer. In Amphibian, this structure is formed by gastrocoel roof plate, which emerges from superficial suprablastoporal cells. GRP is subdivided into medial area, which generates leftward flow by rotating monocilia and lateral Nodal1 expressing areas, which are involved in sensing of the flow. After successful symmetry breaking, medial cells are incorporated into a deep layer where they contribute to the axial mesoderm, while lateral domains join somitic mesoderm.
RESULTS
Here, we performed detailed analysis of spatial and temporal gene expression of important markers and the corresponding morphology of emerging GRP. Endodermal marker Sox17 and markers of superficial mesoderm display complementary patterns at all studied stages. At early stages, GRP forms Tekt2 positive epithelial domain clearly separated from underlying deep layers, while at later stages, this separation disappears. Marker of early somitic mesoderm MyoD1 was absent in emerging GRP and was induced together with Nodal1 during early neurulation. Decreasing morphological separation is accompanied by lateral to medial covering of GRP by endoderm.
CONCLUSION
Our data supports continuous link between superficial mesoderm at the start of gastrulation and mature GRP and suggests late induction of somitic fate in lateral GRP.
PubMed: 38934270
DOI: 10.1002/dvdy.722 -
Heliyon Jun 2024The study aimed to examine the impact of increasing environmental temperatures on physiological changes, oxidative stress, nitric oxide production, total antioxidant...
The study aimed to examine the impact of increasing environmental temperatures on physiological changes, oxidative stress, nitric oxide production, total antioxidant capacity, and blood cell viability in American bullfrog crossbreeds. Frogs and frog blood cells were exposed to temperature ranges of 25-33 °C and 25-37 °C, respectively. Physiological parameters (body temperature, pulse rate, ventilation rate, and oxygen saturation) and biochemical parameters (total antioxidant power, hydrogen peroxide, malondialdehyde, nitric oxide, and mitochondrial activity) were measured at every 2 °C increment. Results showed that body temperature rose with increased environmental temperature ( < 0.05). Pulse rates at 33 °C were higher than those at 25-31 °C ( < 0.05). Ventilation rates at 31 °C exceeded those at 25 °C and 27 °C ( < 0.05). Oxygen saturation levels remained stable at 25-33 °C ( > 0.05). Total antioxidant power at 25 °C was greater than at 27-37 °C ( < 0.05). Hydrogen peroxide levels at 27 °C were higher compared to 25 °C and 31-37 °C ( < 0.05). Malondialdehyde levels at 25-33 °C were higher than at 35 °C and 37 °C ( < 0.05). Nitric oxide levels at 37 °C were higher than at 25-33 °C ( < 0.05), and at 35 °C were higher than at 25-31 °C (P < 0.05). Blood cell viability at 25-31 °C was higher than at 37 °C ( < 0.05). These results suggest that at an environmental temperature of 33 °C, the frogs' body temperature approached 31 °C or higher, and were likely to be harmful to the frogs. Finally, the environmental temperature that caused frog blood cell death was 37 °C.
PubMed: 38933952
DOI: 10.1016/j.heliyon.2024.e32416 -
Animals : An Open Access Journal From... Jun 2024Amphibians serve as reliable indicators of ecosystem health and are the most threatened group of vertebrates. Studies on their spatial distribution pattern and threats...
Amphibians serve as reliable indicators of ecosystem health and are the most threatened group of vertebrates. Studies on their spatial distribution pattern and threats are crucial to formulate conservation strategies. Gongga Mountains, with a peak at 7509 m a.s.l. and running latitudinally, are in the center of the Hengduan Mountains Range and at the eastern steep edge of the Qinghai-Xizang Plateau, providing heterogeneous habitats and varied niches for amphibians. In this study, we combined 83 days of field work with information from 3894 museum specimens that were collected over the past 80 years, and identified twenty amphibian species belonging to seven families and twelve genera by morphology. Of these species, seven were listed in the threatened categories of the Red List of China's Biodiversity and thirteen were endemic to China. Ten species were found on the plateau side (western slope) and eleven species were found on the other side close to the Sichuan Basin (eastern slope). Only one species was found on both sides, indicating different community structures horizontally. The species richness was unimodal vertically and peaking at mid elevation on both sides, with the maximum number (ten vs. nine) of species occurring at 3300-3700 vs. 1700-1900 m a.s.l. and in different types of vegetation. The elevation span and body length of species distributed on both slopes did not show significant differences. These findings help to understand the horizontal and vertical distribution pattern of amphibian diversity, laying a foundation for future biogeographical and conservation research in this area.
PubMed: 38929342
DOI: 10.3390/ani14121723 -
Animals : An Open Access Journal From... Jun 2024Species recognition is a crucial part of understanding the abundance and distribution of various organisms and is important for biodiversity conservation and management....
Species recognition is a crucial part of understanding the abundance and distribution of various organisms and is important for biodiversity conservation and management. Traditional vision-based deep learning-driven species recognition requires large amounts of well-labeled, high-quality image data, the collection of which is challenging for rare and endangered species. In addition, recognition methods designed based on specific species have poor generalization ability and are difficult to adapt to new species recognition scenarios. To address these issues, zero-shot species recognition based on Contrastive Language-Image Pre-training (CLIP) has become a research hotspot. However, previous studies have primarily utilized visual descriptive information and taxonomic information of species to improve zero-shot recognition performance, and the use of geographic distribution characteristics of species to improve zero-shot recognition performance has not been explored. To fill this gap, we proposed a CLIP-driven zero-shot species recognition method that incorporates knowledge of the geographic distribution of species. First, we designed three prompts based on the species geographic distribution statistical data. Then, the latitude and longitude coordinate information attached to each image in the species dataset was converted into addresses, and they were integrated together to form the geographical distribution knowledge of each species. Finally, species recognition results were derived by calculating the similarity after acquiring features by the trained CLIP image encoder and text encoder. We conducted extensive experiments on multiple species datasets from the iNaturalist 2021 dataset, where the zero-shot recognition accuracies of mammals, mollusks, reptiles, amphibians, birds, and insects were 44.96%, 15.27%, 17.51%, 9.47%, 28.35%, and 7.03%, an improvement of 2.07%, 0.48%, 0.35%, 1.12%, 1.64%, and 0.61%, respectively, as compared to CLIP with default prompt. The experimental results show that the fusion of geographic distribution statistical data can effectively improve the performance of zero-shot species recognition, which provides a new way to utilize species domain knowledge.
PubMed: 38929335
DOI: 10.3390/ani14121716 -
BMC Biotechnology Jun 2024Mammalian display is an appealing technology for therapeutic antibody development. Despite the advantages of mammalian display, such as full-length IgG display with...
BACKGROUND
Mammalian display is an appealing technology for therapeutic antibody development. Despite the advantages of mammalian display, such as full-length IgG display with mammalian glycosylation and its inherent ability to select antibodies with good biophysical properties, the restricted library size and large culture volumes remain challenges. Bxb1 serine integrase is commonly used for the stable genomic integration of antibody genes into mammalian cells, but presently lacks the efficiency required for the display of large mammalian display libraries. To increase the Bxb1 integrase-mediated stable integration efficiency, our study investigates factors that potentially affect the nuclear localization of Bxb1 integrase.
METHODS
In an attempt to enhance Bxb1 serine integrase-mediated integration efficiency, we fused various nuclear localization signals (NLS) to the N- and C-termini of the integrase. Concurrently, we co-expressed multiple proteins associated with nuclear transport to assess their impact on the stable integration efficiency of green fluorescent protein (GFP)-encoding DNA and an antibody display cassette into the genome of Chinese hamster ovary (CHO) cells containing a landing pad for Bxb1 integrase-mediated integration.
RESULTS
The nucleoplasmin NLS from Xenopus laevis, when fused to the C-terminus of Bxb1 integrase, demonstrated the highest enhancement in stable integration efficiency among the tested NLS fusions, exhibiting over a 6-fold improvement compared to Bxb1 integrase lacking an NLS fusion. Subsequent additions of extra NLS fusions to the Bxb1 integrase revealed an additional 131% enhancement in stable integration efficiency with the inclusion of two copies of C-terminal nucleoplasmin NLS fusions. Further improvement was achieved by co-expressing the Ran GTPase-activating protein (RanGAP). Finally, to validate the applicability of these findings to more complex proteins, the DNA encoding the membrane-bound clinical antibody abrilumab was stably integrated into the genome of CHO cells using Bxb1 integrase with two copies of C-terminal nucleoplasmin NLS fusions and co-expression of RanGAP. This approach demonstrated over 14-fold increase in integration efficiency compared to Bxb1 integrase lacking an NLS fusion.
CONCLUSIONS
This study demonstrates that optimizing the NLS sequence fusion for Bxb1 integrase significantly enhances the stable genomic integration efficiency. These findings provide a practical approach for constructing larger libraries in mammalian cells through the stable integration of genes into a genomic landing pad.
Topics: Animals; CHO Cells; Integrases; Cricetulus; Nuclear Localization Signals; Cell Nucleus; Serine; Green Fluorescent Proteins; Cricetinae; Xenopus laevis
PubMed: 38926833
DOI: 10.1186/s12896-024-00871-4 -
Nature Jun 2024Many threats to biodiversity cannot be eliminated; for example, invasive pathogens may be ubiquitous. Chytridiomycosis is a fungal disease that has spread worldwide,...
Many threats to biodiversity cannot be eliminated; for example, invasive pathogens may be ubiquitous. Chytridiomycosis is a fungal disease that has spread worldwide, driving at least 90 amphibian species to extinction, and severely affecting hundreds of others. Once the disease spreads to a new environment, it is likely to become a permanent part of that ecosystem. To enable coexistence with chytridiomycosis in the field, we devised an intervention that exploits host defences and pathogen vulnerabilities. Here we show that sunlight-heated artificial refugia attract endangered frogs and enable body temperatures high enough to clear infections, and that having recovered in this way, frogs are subsequently resistant to chytridiomycosis even under cool conditions that are optimal for fungal growth. Our results provide a simple, inexpensive and widely applicable strategy to buffer frogs against chytridiomycosis in nature. The refugia are immediately useful for the endangered species we tested and will have broader utility for amphibian species with similar ecologies. Furthermore, our concept could be applied to other wildlife diseases in which differences in host and pathogen physiologies can be exploited. The refugia are made from cheap and readily available materials and therefore could be rapidly adopted by wildlife managers and the public. In summary, habitat protection alone cannot protect species that are affected by invasive diseases, but simple manipulations to microhabitat structure could spell the difference between the extinction and the persistence of endangered amphibians.
PubMed: 38926575
DOI: 10.1038/s41586-024-07582-y -
Development, Growth & Differentiation Jun 2024During the formation of the neural tube, the primordium of the vertebrate central nervous system, the actomyosin activity of cells in different regions drives neural...
During the formation of the neural tube, the primordium of the vertebrate central nervous system, the actomyosin activity of cells in different regions drives neural plate bending. However, how the stiffness of the neural plate and surrounding tissues is regulated and mechanically influences neural plate bending has not been elucidated. Here, we used atomic force microscopy to reveal the relationship between the stiffness of the neural plate and the mesoderm during Xenopus neural tube formation. Measurements with intact embryos revealed that the stiffness of the neural plate was consistently higher compared with the non-neural ectoderm and that it increased in an actomyosin activity-dependent manner during neural plate bending. Interestingly, measurements of isolated tissue explants also revealed that the relationship between the stiffness of the apical and basal sides of the neural plate was reversed during bending and that the stiffness of the mesoderm was lower than that of the basal side of the neural plate. The experimental elevation of mesoderm stiffness delayed neural plate bending, suggesting that low mesoderm stiffness mechanically supports neural tube closure. This study provides an example of mechanical interactions between tissues during large-scale morphogenetic movements.
PubMed: 38925637
DOI: 10.1111/dgd.12936