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1.
Sci Rep ; 13(1): 12548, 2023 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-37532809

RESUMO

Melanoma is a type of cancer with abnormal proliferation of melanocytes and is one of the most diagnosed cancer types. In traditional Chinese medicine, pangolin scales have been used to treat various diseases, including human cancers. However, its efficacy has not been scientifically proven. Here we studied the anticancer effect and mechanism of pangolin scale extract (PSE) on melanoma cell lines using scientific approaches. Our cell viability assay shows that PSE exhibits up to approximately 50-80% inhibition on SK-MEL-103 and A375 melanoma cell lines. Mechanically, PSE inhibits melanoma cell proliferation, migration, and causes changes in cell morphology. The apoptosis assay showed a significant chromosomal condensation inside the PSE-treated melanoma cells. The sequencing and analysis of A375 melanoma cell transcriptomes revealed 3077 differentially expressed genes in the 6 h treatment group and 8027 differentially expressed genes in the 72 h treatment group. Transcriptome analysis suggests that PSE may cause cell cycle arrest in melanoma cells and promote apoptosis mainly by up-regulating the p53 signaling pathway and down-regulating the PI3K-Akt signaling pathway. In this study, the anticancer effect of PSE was demonstrated by molecular biological means. PSE shows a significant inhibition effect on melanoma cell proliferation and cell migration in vitro, causes cell cycle arrest and promotes apoptosis through p53 and PI3K-AKT pathways. This study provides better insights into the anti-cancer efficacy and underlying mechanism of PSE and a theoretical basis for mining anticancer compounds or the development of new treatments for melanoma in the future. It is worth noting that this study does not advocate the use of the pangolin scale for disease treatment, but only to confirm its usefulness from a scientific research perspective and to encourage subsequent research around the development of active compounds to replace pangolin scales to achieve the conservation of this endangered species.


Assuntos
Escamas de Animais , Melanoma , Animais , Humanos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Escamas de Animais/metabolismo , Pangolins/metabolismo , Linhagem Celular Tumoral , Melanoma/tratamento farmacológico , Melanoma/genética , Melanoma/metabolismo , Proliferação de Células , Apoptose
2.
Nature ; 608(7923): 563-568, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35859171

RESUMO

A fundamental gap in the study of the origin of limbed vertebrates lies in understanding the morphological and functional diversity of their closest relatives. Whereas analyses of the elpistostegalians Panderichthys rhombolepis, Tiktaalik roseae and Elpistostege watsoni have revealed a sequence of changes in locomotor, feeding and respiratory structures during the transition1-9, an isolated bone, a putative humerus, has controversially hinted at a wider range in form and function than now recognized10-14. Here we report the discovery of a new elpistostegalian from the Late Devonian period of the Canadian Arctic that shows surprising disparity in the group. The specimen includes partial upper and lower jaws, pharyngeal elements, a pectoral fin and scalation. This new genus is phylogenetically proximate to T. roseae and E. watsoni but evinces notable differences from both taxa and, indeed, other described tetrapodomorphs. Lacking processes, joint orientations and muscle scars indicative of appendage-based support on a hard substrate13, its pectoral fin shows specializations for swimming that are unlike those known from other sarcopterygians. This unexpected morphological and functional diversity represents a previously hidden ecological expansion, a secondary return to open water, near the origin of limbed vertebrates.


Assuntos
Evolução Biológica , Peixes , Fósseis , Nadadeiras de Animais/anatomia & histologia , Escamas de Animais/anatomia & histologia , Animais , Regiões Árticas , Canadá , Peixes/anatomia & histologia , Peixes/classificação , História Antiga , Mandíbula/anatomia & histologia , Faringe/anatomia & histologia , Filogenia , Natação
3.
Int J Clin Pharmacol Ther ; 60(5): 217-224, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35343429

RESUMO

OBJECTIVE: The fraction of drug absorbed (Fa) from the intestine is an important parameter to characterize the pharmacokinetics of a drug. We aimed to search for an experimental system that provides the best parameters for estimating the effective permeability (Peff) used for the bottom-up prediction of Fa. MATERIALS AND METHODS: The absorption kinetics of 12 passively absorbed drugs were simulated by a compartment absorption transit (CAT) model using absorption parameters from four different experimental systems: human intestinal epithelial cell (HIEC) monolayer, Caco-2 monolayer, parallel artificial membrane permeability assay (PAMPA), and in situ rat intestinal perfusion. All absorption parameters were obtained from the literature. The in vitro apparent permeability coefficient (Papp) and rat in situ Peff were converted to human Peff using a bottom-up approach for each region, based on the morphological features of the human intestine. The simulated Fa values were compared to the respective observed values. Furthermore, plasma concentration profiles of the drugs were simulated by convolution using the time-course of the absorption rate simulated using the Peff values calculated from the HIEC Papp. RESULTS: The Fa values were best predicted by using the Peff values calculated from HEIC, within a 1.3-fold range of observed Fa in 11 out of 12 drugs. The simulated Cmax values of pharmacokinetic simulation using HIEC Papp fell within a 1.5-fold range of observed values for all the drugs examined. CONCLUSION: The HIEC monolayer was identified as the most suitable permeation parameter for estimating Fa and Cmax using a morphological feature-based bottom-up approach.


Assuntos
Escamas de Animais , Absorção Intestinal , Animais , Células CACO-2 , Trato Gastrointestinal , Humanos , Intestinos , Membranas Artificiais , Ratos
4.
Biol Rev Camb Philos Soc ; 97(3): 960-1004, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34991180

RESUMO

Modern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in the group of theropod dinosaurs (Maniraptoriformes) that include crown Aves. Squamous or scaly reptilian-like skin is, however, considered the plesiomorphic condition for theropods and dinosaurs more broadly. Here, we review the morphology and distribution of non-feathered integumentary structures in non-avialan theropods, covering squamous skin and naked skin as well as dermal ossifications. The integumentary record of non-averostran theropods is limited to tracks, which ubiquitously show a covering of tiny reticulate scales on the plantar surface of the pes. This is consistent also with younger averostran body fossils, which confirm an arthral arrangement of the digital pads. Among averostrans, squamous skin is confirmed in Ceratosauria (Carnotaurus), Allosauroidea (Allosaurus, Concavenator, Lourinhanosaurus), Compsognathidae (Juravenator), and Tyrannosauroidea (Santanaraptor, Albertosaurus, Daspletosaurus, Gorgosaurus, Tarbosaurus, Tyrannosaurus), whereas dermal ossifications consisting of sagittate and mosaic osteoderms are restricted to Ceratosaurus. Naked, non-scale bearing skin is found in the contentious tetanuran Sciurumimus, ornithomimosaurians (Ornithomimus) and possibly tyrannosauroids (Santanaraptor), and also on the patagia of scansoriopterygids (Ambopteryx, Yi). Scales are surprisingly conservative among non-avialan theropods compared to some dinosaurian groups (e.g. hadrosaurids); however, the limited preservation of tegument on most specimens hinders further interrogation. Scale patterns vary among and/or within body regions in Carnotaurus, Concavenator and Juravenator, and include polarised, snake-like ventral scales on the tail of the latter two genera. Unusual but more uniformly distributed patterning also occurs in Tyrannosaurus, whereas feature scales are present only in Albertosaurus and Carnotaurus. Few theropods currently show compelling evidence for the co-occurrence of scales and feathers (e.g. Juravenator, Sinornithosaurus), although reticulate scales were probably retained on the mani and pedes of many theropods with a heavy plumage. Feathers and filamentous structures appear to have replaced widespread scaly integuments in maniraptorans. Theropod skin, and that of dinosaurs more broadly, remains a virtually untapped area of study and the appropriation of commonly used techniques in other palaeontological fields to the study of skin holds great promise for future insights into the biology, taphonomy and relationships of these extinct animals.


Assuntos
Escamas de Animais , Carcinoma de Células Escamosas , Dinossauros , Animais , Evolução Biológica , Aves , Dinossauros/anatomia & histologia , Plumas/anatomia & histologia , Fósseis , Osteogênese , Filogenia
5.
Elife ; 112022 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-35073257

RESUMO

We developed a multiphoton imaging method to capture neural structure and activity in behaving flies through the intact cuticle. Our measurements showed that the fly head cuticle has surprisingly high transmission at wavelengths >900nm, and the difficulty of through-cuticle imaging is due to the air sacs and/or fat tissue underneath the head cuticle. By compressing or removing the air sacs, we performed multiphoton imaging of the fly brain through the intact cuticle. Our anatomical and functional imaging results show that 2- and 3-photon imaging are comparable in superficial regions such as the mushroom body, but 3-photon imaging is superior in deeper regions such as the central complex and beyond. We further demonstrated 2-photon through-cuticle functional imaging of odor-evoked calcium responses from the mushroom body γ-lobes in behaving flies short term and long term. The through-cuticle imaging method developed here extends the time limits of in vivo imaging in flies and opens new ways to capture neural structure and activity from the fly brain.


Assuntos
Encéfalo/diagnóstico por imagem , Drosophila/fisiologia , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Corpos Pedunculados/diagnóstico por imagem , Escamas de Animais/fisiologia , Animais , Feminino , Masculino
6.
Sci Rep ; 12(1): 126, 2022 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-34997067

RESUMO

The growth of skin appendages, such as hair, feathers and scales, depends on terminal differentiation of epidermal keratinocytes. Here, we investigated keratinocyte differentiation in avian scutate scales. Cells were isolated from the skin on the legs of 1-day old chicks and subjected to single-cell transcriptomics. We identified two distinct populations of differentiated keratinocytes. The first population was characterized by mRNAs encoding cysteine-rich keratins and corneous beta-proteins (CBPs), also known as beta-keratins, of the scale type, indicating that these cells form hard scales. The second population of differentiated keratinocytes contained mRNAs encoding cysteine-poor keratins and keratinocyte-type CBPs, suggesting that these cells form the soft interscale epidermis. We raised an antibody against keratin 9-like cysteine-rich 2 (KRT9LC2), which is encoded by an mRNA enriched in the first keratinocyte population. Immunostaining confirmed expression of KRT9LC2 in the suprabasal epidermal layers of scutate scales but not in interscale epidermis. Keratinocyte differentiation in chicken leg skin resembled that in human skin with regard to the transcriptional upregulation of epidermal differentiation complex genes and genes involved in lipid metabolism and transport. In conclusion, this study defines gene expression programs that build scutate scales and interscale epidermis of birds and reveals evolutionarily conserved keratinocyte differentiation genes.


Assuntos
Escamas de Animais/metabolismo , Proteínas Aviárias/genética , Diferenciação Celular/genética , Galinhas/genética , Perfilação da Expressão Gênica , Queratinócitos/metabolismo , Análise de Célula Única , Transcriptoma , Escamas de Animais/citologia , Animais , Animais Recém-Nascidos , Proteínas Aviárias/metabolismo , Galinhas/metabolismo , Evolução Molecular , Extremidades , RNA-Seq , Especificidade da Espécie , Transcrição Gênica
8.
Biochemistry (Mosc) ; 86(10): 1192-1200, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34903151

RESUMO

Omeprazole suppresses excessive secretion of gastric acid via irreversible inhibition of H+/K+-ATPase in the gastric parietal cells. Recent meta-analysis of data revealed an association between the use of proton pump inhibitors (PPIs) and increased risk of bone fractures, but the underlying molecular mechanism of PPI action remains unclear. In this study, we demonstrated that omeprazole directly influences bone metabolism using a unique in vitro bioassay system with teleost scales, as well as the in vivo model. The in vitro study showed that omeprazole significantly increased the activities of alkaline phosphatase and tartrate-resistant acid phosphatase after 6 h of incubation with this PPI. Expression of mRNAs for several osteoclastic markers was upregulated after 3-h incubation of fish scales with 10-7 M omeprazole. The in vivo experiments revealed that the plasma calcium levels significantly increased in the omeprazole-treated group. The results of in vitro and in vivo studies suggest that omeprazole affects bone cells by increasing bone resorption by upregulating expression of osteoclastic genes and promoting calcium release to the circulation. The suggested in vitro bioassay in fish scales is a practical model that can be used to study the effects of drugs on bone metabolism.


Assuntos
Escamas de Animais/efeitos dos fármacos , Carpa Dourada/metabolismo , Omeprazol/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Escamas de Animais/citologia , Escamas de Animais/metabolismo , Animais , Antiulcerosos/farmacologia , Cálcio/metabolismo , Linfocinas/metabolismo , Modelos Animais , Osteoblastos/metabolismo , Osteoclastos/metabolismo
10.
Mar Drugs ; 19(11)2021 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-34822468

RESUMO

Marine collagen is gaining vast interest because of its high biocompatibility and lack of religious and social restrictions compared with collagen from terrestrial sources. In this study, lizardfish (Synodus macrops) scales were used to isolate acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC). Both ASC and PSC were identified as type I collagen with intact triple-helix structures by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and spectroscopy. The ASC and PSC had high amino acids of 237 residues/1000 residues and 236 residues/1000 residues, respectively. Thus, the maximum transition temperature (Tmax) of ASC (43.2 °C) was higher than that of PSC (42.5 °C). Interestingly, the Tmax of both ASC and PSC was higher than that of rat tail collagen (39.4 °C) and calf skin collagen (35.0 °C), the terrestrial collagen. Solubility tests showed that both ASC and PSC exhibited high solubility in the acidic pH ranges. ASC was less susceptible to the "salting out" effect compared with PSC. Both collagen types were nontoxic to HaCaT and MC3T3-E1 cells, and ASC was associated with a higher cell viability than PSC. These results indicated that ASC from lizardfish scales could be an alternative to terrestrial sources of collagen, with potential for biomedical applications.


Assuntos
Colágeno/química , Peixes , Escamas de Animais , Animais , Organismos Aquáticos , Concentração de Íons de Hidrogênio , Solubilidade , Temperatura
11.
Proc Natl Acad Sci U S A ; 118(49)2021 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-34845021

RESUMO

During metamorphosis, the wings of a butterfly sprout hundreds of thousands of scales with intricate microstructures and nano-structures that determine the wings' optical appearance, wetting characteristics, thermodynamic properties, and aerodynamic behavior. Although the functional characteristics of scales are well known and prove desirable in various applications, the dynamic processes and temporal coordination required to sculpt the scales' many structural features remain poorly understood. Current knowledge of scale growth is primarily gained from ex vivo studies of fixed scale cells at discrete time points; to fully understand scale formation, it is critical to characterize the time-dependent morphological changes throughout their development. Here, we report the continuous, in vivo, label-free imaging of growing scale cells of Vanessa cardui using speckle-correlation reflection phase microscopy. By capturing time-resolved volumetric tissue data together with nanoscale surface height information, we establish a morphological timeline of wing scale formation and gain quantitative insights into the underlying processes involved in scale cell patterning and growth. We identify early differences in the patterning of cover and ground scales on the young wing and quantify geometrical parameters of growing scale features, which suggest that surface growth is critical to structure formation. Our quantitative, time-resolved in vivo imaging of butterfly scale development provides the foundation for decoding the processes and biomechanical principles involved in the formation of functional structures in biological materials.


Assuntos
Escamas de Animais/anatomia & histologia , Escamas de Animais/ultraestrutura , Asas de Animais/anatomia & histologia , Escamas de Animais/fisiologia , Animais , Borboletas/anatomia & histologia , Borboletas/metabolismo , Cor , Lepidópteros/anatomia & histologia , Lepidópteros/metabolismo , Metamorfose Biológica , Morfogênese , Pigmentação , Asas de Animais/fisiologia , Asas de Animais/ultraestrutura
12.
Opt Express ; 29(15): 23368-23380, 2021 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-34614603

RESUMO

Photonic chip-based total internal reflection fluorescence microscopy (c-TIRFM) is an emerging technology enabling a large TIRF excitation area decoupled from the detection objective. Additionally, due to the inherent multimodal nature of wide waveguides, it is a convenient platform for introducing temporal fluctuations in the illumination pattern. The fluorescence fluctuation-based nanoscopy technique multiple signal classification algorithm (MUSICAL) does not assume stochastic independence of the emitter emission and can therefore exploit fluctuations arising from other sources, as such multimodal illumination patterns. In this work, we demonstrate and verify the utilization of fluctuations in the illumination for super-resolution imaging using MUSICAL on actin in salmon keratocytes. The resolution improvement was measured to be 2.2-3.6-fold compared to the corresponding conventional images.


Assuntos
Escamas de Animais/citologia , Epiderme/diagnóstico por imagem , Iluminação , Microscopia de Fluorescência/métodos , Imagem Óptica/métodos , Animais , Fluorescência , Microscopia de Fluorescência/instrumentação , Fótons , Salmão
13.
Sci Rep ; 11(1): 19567, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34599250

RESUMO

Mosquitoes are a great menace for humankind since they transmit pathogenic organisms causing Malaria, Dengue, Chikungunya, Elephantiasis and Japanese encephalitis. There is an urgent need to discover new and novel biological tools to mitigate mosquito-borne diseases. To develop bioinsecticides through newly developed nanotechnology is another option in the present research scenario. In this study we synthesize and characterize sardine fish scales with silver nitrate by adopting various instrumental techniques such as UV- and FTIR-spectroscopy, energy-dispersive X-ray (EDAX), X-ray diffraction analyses (XRD) and scanning electron microscopy (SEM). Toxicity bioassays were conducted with young developmental stages of mosquito vectors. Significant mortality appeared after different life stages of mosquito vectors (young larval and pupal instars were exposed to the nanomaterials). LC50 values were 13.261 ppm for young first instar larvae and 32.182 ppm for pupae. Feeding and predatory potential of G. affinis, before and after exposure to nanoparticles against mosquito larval (I & II) instars of the mosquitoes showed promising results in laboratory experiments. Feeding potential of mosquito fish without nanoparticle treatment was 79.7% and 70.55% for the first and second instar larval populations respectively. At the nanoparticle-exposed situation the predatory efficiency of mosquitofish was 94.15% and 84.3%, respectively. Antioxidant enzymes like (SOD), (CAT), and (LPO) were estimated in the gill region of sardine fish in control and experimental waters. A significant reduction of egg hatchability was evident after nanoparticle application. It became evident from this study that the nano-fabricated materials provide suitable tools to control the malaria vector Anopheles stephensi in the aquatic phase of its life cycle. This finding suggests an effective novel approach to mosquito control.


Assuntos
Escamas de Animais/química , Anopheles/efeitos dos fármacos , Peixes , Inseticidas/química , Inseticidas/farmacologia , Nanopartículas Metálicas/química , Prata , Animais , Anopheles/parasitologia , Fenômenos Químicos , Concentração Inibidora 50 , Insetos Vetores/efeitos dos fármacos , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/parasitologia , Testes de Sensibilidade Parasitária , Prata/química , Análise Espectral
14.
Zool Res ; 42(5): 620-625, 2021 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-34410048

RESUMO

We describe a new species of the genus Hebius and provide evidence for the validity of H. septemlineatuscomb. nov. Morphological and molecular analyses of Hebius specimens collected in Yunnan Province, China, revealed three distinct lineages, namely the newly described Hebius weixiensissp. nov., as well as H. octolineatus (Boulenger, 1904), and H. septemlineatuscomb. nov. (Schmidt 1925), which is removed from synonymy with H. octolineatus. Based on mitochondrial genealogy, Hebius weixiensissp. nov. is sister to H. septemlineatuscomb. nov., while H. octolineatus is sister to H. bitaeniatus. The new species and H. septemlineatuscomb. nov. showed considerable genetic divergence from their recognized congeners (uncorrected P-distance ≥3.9%). Furthermore, the new species and H. septemlineatuscomb. nov. can be diagnosed from closely related congeners by a combination of pholidosis characters.


Assuntos
Colubridae/anatomia & histologia , Colubridae/genética , Filogenia , Escamas de Animais , Animais , China , Feminino , Masculino , Especificidade da Espécie
15.
Sci Rep ; 11(1): 16498, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34389765

RESUMO

The males of more than 80% of the Lycaenidae species belonging to the tribe Polyommatini exhibit structural coloration on their dorsal wing surfaces. These colors have a role in reinforcement in prezygotic reproductive isolation. The species-specific colors are produced by the cellular self-assembly of chitin/air nanocomposites. The spectral position of the reflectance maximum of such photonic nanoarchitectures depends on the nanoscale geometric dimensions of the elements building up the nanostructure. Previous work showed that the coloration of male Polyommatus icarus butterflies in the Western and Eastern Palearctic exhibits a characteristic spectral difference (20 nm). We investigated the coloration and the de novo developed DNA microsatellites of 80 P. icarus specimens from Europe from four sampling locations, spanning a distance of 1621 km. Remarkably good concordance was found between the spectral properties of the blue sexual signaling color (coincident within 5 nm) and the population genetic structure as revealed by 10 microsatellites for the P. icarus species.


Assuntos
Escamas de Animais/anatomia & histologia , Borboletas/genética , Asas de Animais/anatomia & histologia , Animais , Borboletas/anatomia & histologia , Cor , DNA/genética , Europa (Continente) , Masculino , Repetições de Microssatélites/genética , Filogeografia , Espectrofotometria
16.
Int. j. morphol ; 39(4): 1160-1163, ago. 2021. ilus
Artigo em Espanhol | LILACS | ID: biblio-1385458

RESUMO

RESUMEN: Los dentículos dérmicos son estructuras dermales presentes en el grupo de los condrictios, tienen un papel muy importante en su biología y se les ha utilizado como un carácter taxonómico que permiten reconocer grupos o especies. Por lo que en el presente trabajo se compara la morfología dermal de los juveniles de dos especies de tiburones pala, Sphyrna tiburo y S. vespertina, cuyo origen evolutivo está emparentado con el cierre del istmo centroaméricano. Para ello se obtuvieron muestras dermales (1 cm2) de tres regiones corporales y se procesaron para obtener imágenes de alta resolución por medio de Microscopia electrónica de barrido (MEB). Los dentículos de ambas especies tienen un patrón morfológico común, con variaciones en la longitud de las prolongaciones de las crestas, área libre y superposición de los dentículos, y grado de notoriedad de la ornamentación microestructural.


SUMMARY: The dermal denticles are dermal structures present in the group of chondrichthyans, they have a very important role in their biology and they have been used as a taxonomic character that allows to recognize groups or species. Therefore, in the present work, the dermal morphology of the juveniles of two species of shovel sharks, Sphyrna tiburo and S. vespertina, whose evolutionary origin is related to the closure of the Central American isthmus, is compared. For this, dermal samples (1 cm2) from three body regions were obtained and processed to obtain high resolution images by means of scanning electron microscopy (SEM). The denticles of both species have a common morphological pattern, with variations in the length of the ridge extensions, free area and overlapping of the denticles, and the degree of notoriety of the microstructural ornamentation.


Assuntos
Animais , Tubarões/anatomia & histologia , Derme/ultraestrutura , Microscopia Eletrônica de Varredura , Elasmobrânquios/anatomia & histologia , Escamas de Animais/ultraestrutura
17.
Proc Natl Acad Sci U S A ; 118(29)2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34230097

RESUMO

Preexploitation shark baselines and the history of human impact on coral reef-associated shark communities in the Caribbean are tpoorly understood. We recovered shark dermal denticles from mid-Holocene (∼7 ky ago) and modern reef sediments in Bocas del Toro, Caribbean Panama, to reconstruct an empirical shark baseline before major human impact and to quantify how much the modern shark community in the region had shifted from this historical reference point. We found that denticle accumulation rates, a proxy for shark abundance, declined by 71% since the mid-Holocene. All denticle morphotypes, which reflect shark community composition, experienced significant losses, but those morphotypes found on fast-swimming, pelagic sharks (e.g., families Carcharhinidae and Sphyrnidae) declined the most. An analysis of historical records suggested that the steepest decline in shark abundance occurred in the late 20th century, coinciding with the advent of a targeted shark fishery in Panama. Although the disproportionate loss of denticles characterizing pelagic sharks was consistent with overfishing, the large reduction in denticles characterizing demersal species with low commercial value (i.e., the nurse shark Ginglymostoma cirratum) indicated that other stressors could have exacerbated these declines. We demonstrate that the denticle record can reveal changes in shark communities over long ecological timescales, helping to contextualize contemporary abundances and inform shark management and ecology.


Assuntos
Escamas de Animais , Recifes de Corais , Fósseis , Tubarões/fisiologia , Escamas de Animais/citologia , Escamas de Animais/fisiologia , Animais , Região do Caribe , Conservação dos Recursos Naturais , Sedimentos Geológicos/química , Atividades Humanas , Humanos , Panamá , Tubarões/classificação , Fatores de Tempo
18.
Int J Biol Macromol ; 186: 145-154, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34246667

RESUMO

Herein, three types of silver carp scale gelatins were extracted, and their molecular weight distribution, structural properties, functional properties and emulsifying properties were investigated and discussed. Acetic acid-extracted gelatin (AAG), hot water-extracted gelatin (HWG), and pepsin enzyme-extracted gelatin (PEG) showed similar and four clear bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern, whereas they showed different ß chain amounts and ß-sheet percentages. The water-holding capacity values (g/g of gelatin) were: AAG (16.8 ± 1.1) > HWG (14.0 ± 0.7) ≈ PEG (13.5 ± 1.6). The fat-binding capacity values (g/g of gelatin) were: AAG (11.8 ± 0.3) > HWG (9.5 ± 1.3) > PEG (5.3 ± 0.4). Emulsion droplet sizes and creaming index values decreased with the increase of gelatin concentrations for all the fish oil-loaded emulsions stabilized by three types of gelatins. Compared with PEG, AAG and HWG show similar and higher emulsion stability at high gelatin concentration (10 mg/mL). The stabilization mechanism of fish oil-loaded silver carp scale gelatin-stabilized emulsions involved an "extraction method-protein molecular weight distribution-protein molecular structure-molecular interaction-emulsibility-droplet structure-emulsion stability" route. This work would be beneficial for the research on the relationship of structure and function of gelatin and to the comprehensive utilization of aquatic products.


Assuntos
Escamas de Animais/metabolismo , Carpas/metabolismo , Excipientes/química , Óleos de Peixe/química , Proteínas de Peixes/química , Gelatina/química , Animais , Fracionamento Químico , Composição de Medicamentos , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Emulsões , Excipientes/isolamento & purificação , Óleos de Peixe/farmacologia , Proteínas de Peixes/isolamento & purificação , Gelatina/isolamento & purificação , Concentração de Íons de Hidrogênio , Peso Molecular , Tamanho da Partícula , Fatores de Tempo
19.
Dev Biol ; 477: 205-218, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34089732

RESUMO

Thyroid hormone is a key regulator of post-embryonic vertebrate development. Skin is a biomedically important thyroid hormone target organ, but the cellular and molecular mechanisms underlying skin pathologies associated with thyroid dysfunction remain obscure. The transparent skin of zebrafish is an accessible model system for studying vertebrate skin development. During post-embryonic development of the zebrafish, scales emerge in the skin from a hexagonally patterned array of dermal papillae, like other vertebrate skin appendages such as feathers and hair follicles. We show here that thyroid hormone regulates the rate of post-embryonic dermal development through interaction with nuclear hormone receptors. This couples skin development with body growth to generate a well ordered array of correctly proportioned scales. This work extends our knowledge of thyroid hormone actions on skin by providing in-vivo evidence that thyroid hormone regulates multiple aspects of dermal development.


Assuntos
Pele/crescimento & desenvolvimento , Hormônios Tireóideos/fisiologia , Peixe-Zebra/crescimento & desenvolvimento , Escamas de Animais/crescimento & desenvolvimento , Animais , Padronização Corporal/fisiologia , Morfogênese
20.
Curr Biol ; 31(16): 3621-3628.e4, 2021 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-34143958

RESUMO

The extant coelacanth was discovered in 1938;1 its biology and ecology remain poorly known due to the low number of specimens collected. Only two previous studies1,2 have attempted to determine its age and growth. They suggested a maximum lifespan of 20 years, placing the coelacanth among the fastest growing marine fish. These findings are at odds with the coelacanth's other known biological features including low oxygen-extraction capacity, slow metabolism, ovoviviparity, and low fecundity, typical of fish with slow life histories and slow growth. In this study, we use polarized light microscopy to study growth on scales based on a large sample of 27 specimens. Our results demonstrate for the first time nearly imperceptible annual calcified structures (circuli) on the scales and show that maximal age of the coelacanth was underestimated by a factor of 5. Our validation method suggests that circuli are indeed annual, thus supporting that the coelacanth is among the longest-living fish species, its lifespan being probably around 100 years. Like deep-sea sharks with a reduced metabolism, the coelacanth has among the slowest growth for its size. Further reappraisals of age at first sexual maturity (in the range 40 to 69 years old) and gestation duration (of around 5 years) show that the living coelacanth has one of the slowest life histories of all marine fish and possibly the longest gestation. As long-lived species with slow life histories are extremely vulnerable to natural and anthropogenic perturbations, our results suggest that coelacanths may be more threatened than previously considered.


Assuntos
Peixes/crescimento & desenvolvimento , Longevidade , Escamas de Animais , Animais
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