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1.
Gene ; 731: 144334, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-31935508

RESUMO

SOX9 plays a crucial, extensive and conservative role in the process of somatic tissue development and adult regeneration through the positive self-regulation mediated by SOM across all vertebrates. In this study, we have cloned SOX9 from the kidney of hatchling Alligator sinensis. The full-length of SOX9 cDNA is 3878 bp with an open reading frame encoding 494 amino acids. Amino acid alignment analyses indicated that the SOX9 exhibit highly conserved functional domains. Using the droplet digital PCR, the mRNA abundances of SOX9 during nephrogenesis in A. sinensis showed prominent changes in the embryonic development, suggesting that SOX9 might combines a vital role in the regulation of complex renal development. Interestingly, we detected the nucleocytoplasmic shuttling of SOX9 protein using immunofluorescence, implying that nucleocytoplasmic shuttling is critical to the regulation of SOX9 in the renal embryonic development. Collectively, these data provide an important foundation for further studies on renal developmental biology and molecular biology of non-mammalian SOX9. Furthermore, it provides new insights into the phenomenon of SOX9 nucleocytoplasmic shuttling in Alligator sinensis, which is probably of great significance to the development of kidney metanephros embryo.


Assuntos
Jacarés e Crocodilos , Rim/embriologia , Rim/metabolismo , Fatores de Transcrição SOX9/genética , Fatores de Transcrição SOX9/metabolismo , Transporte Ativo do Núcleo Celular , Jacarés e Crocodilos/embriologia , Jacarés e Crocodilos/genética , Jacarés e Crocodilos/metabolismo , Animais , Núcleo Celular/metabolismo , Clonagem Molecular , Regulação da Expressão Gênica no Desenvolvimento , Organogênese/genética , Transporte de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
2.
PLoS One ; 14(8): e0205862, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31461452

RESUMO

Translocated saltwater crocodiles (Crocodylus porosus) in the Northern Territory (NT) of Australia often return to their original capture sites, which complicates management interventions aimed at reducing human-crocodile conflict. We examined the spatial events implicated in this homing ability, using ARGOS satellite tracking devices. Five large male C. porosus (3.03 m to 4.02 m TL) were shifted and released 100-320 km from their capture sites, and 3 additional ones (3.67 m to 4.23 m TL) were released at their site of capture as controls. Translocated crocodiles were more mobile than the controls, and moved at sea in the direction of their original capture site. However, they were unable or unwilling to swim around a geographic structure, Cobourg Peninsula, which prevented homing being achieved in all five cases. Two control crocodiles remained near their capture sites, but one, after the first year, made a 900km journey for six months, before returning to its original capture and release site. Genetic analysis of tissue samples from nests across the NT coast demonstrated significant genetic structure across the coast, and confirmed that Cobourg Peninsula contributes to genetic differentiation among populations along the NT coast. These results provide new insights into C. porosus movements, which have management significance for the maintenance of public safety.


Assuntos
Jacarés e Crocodilos/genética , Jacarés e Crocodilos/fisiologia , Distribuição Animal , Geografia , Comportamento de Retorno ao Território Vital , Movimento , Animais , Estruturas Genéticas , Masculino , Astronave
3.
Artigo em Inglês | MEDLINE | ID: mdl-30945985

RESUMO

Consumption and exploitation of crocodiles have been rampant for their exotic, nutritive and medicinal attributes. These depredations are alarming and although they have continued to be monitored by wildlife and conservation agencies, unlawful trading of crocodiles shows an increasing trend worldwide. Recently, conventional polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) assays for crocodile have been documented but they are only suitable for identification and cannot quantify adulterations. We described here a quantitative duplex real-time PCR assay with probes to quantify contributions from Crocodylus porosus materials simultaneously. A very short amplicon size of 127bp was used because longer targets could have been broken down in samples, bringing considerable uncertainty in molecular analysis. We have validated a TaqMan probe-based duplex real-time PCR (qPCR) assay for the detection of 0.004 ng DNA in pure state and 0.1% target meat in model chicken meatball. False negative detection was eliminated through an endogenous control (141-bp site of eukaryotic 18S rRNA). Analysis of 12 model chicken meatballs adulterated with C. porosus reflected 96.3-120.2% target recovery at 0.1-10% adulterations. A validation test of 21 commercial food and traditional medicine (TM) crocodile-based products showed 100% effectiveness. Short amplicon sizes, alternative complementary target, exceptional stability and superior sensitivity suggested the assay could be used for the identification and quantitative determination of C. porosus in any food or TM samples even under degraded conditions.


Assuntos
Jacarés e Crocodilos/genética , Sondas de DNA/genética , Contaminação de Alimentos/análise , Abastecimento de Alimentos , Medicina Tradicional , Reação em Cadeia da Polimerase em Tempo Real , Animais
4.
Mol Biol Rep ; 46(2): 2473-2484, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30852718

RESUMO

We isolated and characterized 10 new microsatellites loci for Paleosuchus trigonatus using ION TORRENT Sequencing Technology. We tested the transferability of these loci to three related species of the subfamily Caimaninae, and used these bi-parental markers to test population structure and genetic diversity of two populations of P. trigonatus impacted by hydroelectric dam construction on the Madeira (N = 16) and Xingu (N = 16) rivers. We also investigated the transferability of these markers to three related species: Paleosuchus palpebrosus (N = 5), Caiman crocodilus (N = 6) and Melanosuchus niger (N = 6). The genetic diversity of P. trigonatus was low in both the Madeira (He: 0.535 ± 0.148) and Xingu (He: 0.381 ± 0.222) populations, but the loci were sufficiently polymorphic to be used in system of mating and kinship studies in P. trigonatus. DAPC analysis with our set of microsatellites loci was able to separate the four species of Caimaninae studied and to detect a shallow genetic structure between Madeira and Xingu populations of P. trigonatus. AMOVA and STRUCTURE analyses using locprior model corroborate this shallow genetic structure. These novel molecular markers will be also useful in conservation genetics and phylogeographic studies of P. trigonatus, since they improve our ability to monitor the putative effects of dams on the loss of genetic diversity and allow us to investigate population dynamics and microevolutionary processes that occurred in the species.


Assuntos
Jacarés e Crocodilos/genética , Genética Populacional/métodos , Jacarés e Crocodilos/metabolismo , Animais , Brasil , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Repetições de Microssatélites/genética , Rios
5.
Methods Mol Biol ; 1920: 247-263, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30737695

RESUMO

Reptiles have great taxonomic diversity that is reflected in their morphology, ecology, physiology, modes of reproduction, and development. Interest in comparative and evolutionary developmental biology makes protocols for the study of reptile embryos invaluable resources. The relatively large size, seasonal breeding, and long gestation times of turtles epitomize the challenges faced by the developmental biologist. We describe protocols for the preparation of turtle embryos for ex ovo culture, electroporation, in situ hybridization, and microcomputed tomography. Because these protocols have been adapted and optimized from methods used for frog, chick, and mouse embryos, it is likely that they could be used for other reptilian species. Notes are included for alligator embryos where appropriate.


Assuntos
Jacarés e Crocodilos/embriologia , Desenvolvimento Embrionário , Tartarugas/embriologia , Jacarés e Crocodilos/genética , Animais , Biomarcadores , Eletroporação , Técnicas de Cultura Embrionária , Desenvolvimento Embrionário/genética , Regulação da Expressão Gênica no Desenvolvimento , Hibridização In Situ , Tartarugas/genética , Microtomografia por Raio-X
6.
Mol Ecol ; 28(5): 936-950, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30659682

RESUMO

Endangered species are often characterized by low genetic diversity and it is imperative for conservation efforts to incorporate the knowledge obtained from genetic studies for effective management. However, despite the promise of technological advances in sequencing, application of genome-wide data to endangered populations remains uncommon. In the present study we pursued a holistic conservation-genomic approach to inform a field-based management programme of a Critically Endangered species, the Siamese crocodile Crocodylus siamensis. Using thousands of single nucleotide polymorphisms from throughout the genome, we revealed signals of introgression from two other crocodile species within our sample of both wild and captive-bred Siamese crocodiles from Cambodia. Our genetic screening of the Siamese crocodiles resulted in the subsequent re-introduction of 12 individuals into the wild as well as the selection of four individuals for captive breeding programmes. Comparison of intraspecific genetic diversity revealed an alarmingly low contemporary effective population size in the wild (<50) with evidence of a recent bottleneck around Tonle Sap Lake. We also projected a probable future extinction in the wild (within fewer than five generations) in this population in the absence of re-introduction efforts. However, an increase in the number of potential breeders through re-introductions, including the one resulting from this project, could counter this trend. Our results have been implemented in ongoing re-introduction and captive breeding programmes, with major implications for the conservation management of Siamese crocodiles, and provide a blueprint for the rescue effort of other "terminally ill" populations of critically endangered species.


Assuntos
Jacarés e Crocodilos/genética , Conservação dos Recursos Naturais , Espécies em Perigo de Extinção , Genômica , Animais , Cruzamento , Repetições de Microssatélites
7.
Biol Reprod ; 100(1): 149-161, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30010799

RESUMO

Estrogens regulate key aspects of sexual determination and differentiation, and exposure to exogenous estrogens can alter ovarian development. Alligators inhabiting Lake Apopka, FL, are historically exposed to estrogenic endocrine disrupting contaminants and are characterized by a suite of reproductive abnormalities, including altered ovarian gene expression and abated transcriptional responses to follicle stimulating hormone. Here, we test the hypothesis that disrupting estrogen signaling during gonadal differentiation results in persistent alterations to ovarian gene expression that mirror alterations observed in alligators from Lake Apopka. Alligator embryos collected from a reference site lacking environmental contamination were exposed to estradiol-17 beta or a nonaromatizable androgen in ovo and raised to the juvenile stage. Changes in basal and gonadotropin-challenged ovarian gene expression were then compared to Apopka juveniles raised under identical conditions. Assessing basal transcription in untreated reference and Apopka animals revealed a consistent pattern of differential expression of key ovarian genes. For each gene where basal expression differed across sites, in ovo estradiol treatment in reference individuals recapitulated patterns observed in Apopka alligators. Among those genes affected by site and estradiol treatment were three aryl hydrocarbon receptor (AHR) isoforms, suggesting that developmental estrogen signaling might program sensitivity to AHR ligands later in life. Treatment with gonadotropins stimulated strong ovarian transcriptional responses; however, the magnitude of responses was not strongly affected by steroid hormone treatment. Collectively, these findings demonstrate that precocious estrogen signaling in the developing ovary likely underlies altered transcriptional profiles observed in a natural population exposed to endocrine disrupting contaminants.


Assuntos
Jacarés e Crocodilos , Embrião não Mamífero/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Estrogênios/toxicidade , Exposição Materna/efeitos adversos , Ovário/efeitos dos fármacos , Jacarés e Crocodilos/embriologia , Jacarés e Crocodilos/genética , Animais , Reprogramação Celular/efeitos dos fármacos , Reprogramação Celular/genética , Embrião não Mamífero/metabolismo , Desenvolvimento Embrionário/efeitos dos fármacos , Desenvolvimento Embrionário/genética , Exposição Ambiental/efeitos adversos , Feminino , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Lagos , Modelos Animais , Ovário/metabolismo , Oviparidade/efeitos dos fármacos , Oviparidade/genética , Transcriptoma/efeitos dos fármacos , Transcriptoma/genética , Poluentes Químicos da Água/toxicidade
8.
Gen Comp Endocrinol ; 271: 61-72, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30408484

RESUMO

The thyroid gland is sensitive to steroid hormone signaling, and many thyroid disrupting contaminants also disrupt steroid hormone homeostasis, presenting the possibility that thyroid disruption may occur through altered steroid hormone signaling. To examine this possibility, we studied short-term and persistent impacts of embryonic sex steroid exposure on thyroid physiology in the American alligator. Alligators from a lake contaminated with endocrine disrupting contaminants (Lake Apopka, FL, USA) have been shown to display characteristics of thyroid and steroid hormone disruption. Previous studies suggest these alterations arise during development and raise the possibility that exposure to maternally deposited contaminants might underlie persistent organizational changes in both thyroidal and reproductive function. Thus, this population provides a system to investigate contaminant-mediated organizational thyroid disruption in an environmentally-relevant context. We assess the developmental expression of genetic pathways involved in thyroid hormone biosynthesis and find that expression of these genes increases prior to hatching. Further, we show that nuclear steroid hormone receptors are also expressed during this period, indicating the developing thyroid is potentially responsive to steroid hormone signaling. We then explore functional roles of steroid signaling during development on subsequent thyroid function in juvenile alligators. We exposed alligator eggs collected from both Lake Apopka and a reference site to 17ß-estradiol and a non-aromatizable androgen during embryonic development, and investigated effects of exposure on hatchling morphometrics and thyroidal gene expression profiles at 5 months of age. Steroid hormone treatment did not impact the timing of hatching or hatchling size. Furthermore, treatment with steroid hormones did not result in detectable impacts on thyroid transcriptional programs, suggesting that precocious or excess estrogen and androgen exposure does not influence immediate or long-term thyroidal physiology.


Assuntos
Jacarés e Crocodilos/genética , Jacarés e Crocodilos/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Esteroides/efeitos adversos , Glândula Tireoide/fisiologia , Jacarés e Crocodilos/embriologia , Animais , Vias Biossintéticas/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Hormônios Esteroides Gonadais/genética , Hormônios Esteroides Gonadais/metabolismo , Modelos Lineares , Masculino , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Glândula Tireoide/embriologia , Hormônios Tireóideos/biossíntese
9.
Front Immunol ; 9: 2626, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30483270

RESUMO

Toll-like receptors (TLRs) form an ancient family of innate immune receptors that detect microbial structures and activate the host immune response. Most subfamilies of TLRs (including TLR3, TLR5, and TLR7) are highly conserved among vertebrate species. In contrast, TLR15, a member of the TLR1 subfamily, appears to be unique to birds and reptiles. We investigated the functional evolution of TLR15. Phylogenetic and synteny analyses revealed putative TLR15 orthologs in bird species, several reptilian species and also in a shark species, pointing to an unprecedented date of origin of TLR15 as well as large scale reciprocal loss of this TLR in most other vertebrates. Cloning and functional analysis of TLR15 of the green anole lizard (Anolis carolinensis), salt water crocodile (Crocodylus porosus), American alligator (Alligator mississippiensis), and chicken (Gallus gallus) showed for all species TLR15 specific protease-induced activation of NF-κB, despite highly variable TLR15 protein expression levels. The variable TLR15 expression was consistent in both human and reptilian cells and could be attributed to species-specific differences in TLR15 codon usage. The species-specific codon bias was not or barely noted for more evolutionarily conserved TLRs (e.g., TLR3). Overall, our results indicate that TLR15 originates before the divergence of chondrichthyes fish and tetrapods and that TLR15 of both avian and reptilian species has a conserved function as protease activated receptor. The species-specific codon usage and large scale loss of TLR15 in most vertebrates suggest evolutionary regression of this ancient TLR.


Assuntos
Códon/genética , Receptores Toll-Like/genética , Jacarés e Crocodilos/genética , Animais , Evolução Biológica , Linhagem Celular , Galinhas/genética , Células HEK293 , Humanos , Lagartos/genética , NF-kappa B/genética , Filogenia , Serpentes/genética , Especificidade da Espécie
10.
Gene ; 674: 178-187, 2018 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-29958951

RESUMO

Sex steroid hormones play an important role in mediating physiological responses and developmental processes through their receptors across all vertebrates. Chinese alligator (Alligator sinensis) is a critically endangered reptile species unique to China. In this study, we have cloned one of the sex steroid hormone receptor genes, androgen receptor (AR) from the brain of Chinese alligator for the first time. The full-length AR cDNA is 2717 bp in length with an open reading frame (ORF) encoding 722 amino acids. Amino acid alignment analyses indicated that the ARs exhibit highly conserved functional domains. Especially, the P-box and D-box, which are essential to ensure that receptor binding to the androgen response elements, are completely conserved in selected species. Using the quantitative real-time PCR (qPCR), the spatial expression of four receptor mRNAs in all newborn brain tissues and temporal expression of them in the cerebrum during the embryonic development in Chinese alligators were investigated. The results of qPCR showed ubiquitous expression of the four receptor mRNAs in all newborn brain tissues examined and significant changes in the expression levels of these receptor mRNAs in the embryonic development. These results suggest that sex steroid hormones might play an important role in the regulation of complex neuroendocrine activities in newborn Chinese alligator. Furthermore, these data provide an important foundation for further studies on endocrinology and molecular biology of non-mammalian sex steroid hormone receptors.


Assuntos
Encéfalo/metabolismo , Receptores Androgênicos/genética , Receptores de Esteroides/metabolismo , Jacarés e Crocodilos/embriologia , Jacarés e Crocodilos/genética , Jacarés e Crocodilos/crescimento & desenvolvimento , Jacarés e Crocodilos/metabolismo , Animais , Animais Recém-Nascidos , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Clonagem Molecular , Feminino , Expressão Gênica , Masculino , Filogenia , Receptores Androgênicos/metabolismo , Receptores Estrogênicos/genética , Receptores Estrogênicos/metabolismo , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismo , Alinhamento de Sequência
11.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 40(2): 201-210, 2018 Apr 28.
Artigo em Chinês | MEDLINE | ID: mdl-29724310

RESUMO

Objective To investigate the molecular clone and structural features of pepsinogen C(PGC) gene in the stomach of Alligator sinensis,explore the phylogenetic relationships and tissue distribution,and analyze the variation of PGC expression in the stomachs of adult Alligator sinensis at different life stages. Methods The full-length cDNA of PGC gene of Alligator sinensis was cloned by reverse transcription polymerase chain reaction and rapid amplification of cDNA ends and then sequenced.The physical and chemical parameters and advanced structures of the PGC protein were predicted by bioinformatics methods and tools.The PGC amino acid sequences of the Alligator sinensis and other vertebrates were compared by Clustal X software.The neighbor-joining phylogenetic tree was built by MEGA 6 software.Immunohistochemistry was used to locate PGC in the gastric mucosa of Alligator sinensis.The variation of the PGC mRNA levels in the stomach at different life stages was detected by quantitative real-time polymerase chain reaction.Results Reverse transcription polymerase chain reaction and rapid amplification of cDNA ends revealed a 1568 bp cDNA full-length sequence containing 1167 bp open reading frame,which encoded 388 amino acids.The PGC gene of Alligator sinensis had been deposited in the GenBank Data Libraries under the accession number of KY799383.Bioinformatics analysis predicted that the Alligator sinensis PGC had a theoretical relative molecular mass of 41 998 with a theoretical isoelectric point of 4.16.In addition,the three-dimensional structure of the PGC was constructed by homology modeling to predict its active site with two essential aspartyl residues and six essential cysteine residues involved in forming three disulphide bonds.The neighbor-joining phylogenetic tree of vertebrates from the amino acids sequences of PGC showed all crocodiles were clustered as a group,and the PGC of Alligator sinensis was the closest to Alligator mississippiensis.Alligator sinensis PGC was specifically expressed in the gastric mucosa,and its expressions significantly differed during reproduction and hibernation significantly(P<0.05).Conclusions Alligator sinensis PGC gene is highly conserved in evolution.Its protein is a gastric specific digestive proteinase that belongs to a aspartic proteinase family.


Assuntos
Jacarés e Crocodilos/genética , Pepsinogênio C/genética , Filogenia , Proteínas de Répteis/genética , Animais , Clonagem Molecular , Análise de Sequência , Estômago
12.
BMC Bioinformatics ; 19(1): 105, 2018 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-29587630

RESUMO

BACKGROUND: DNA methylation patterns store epigenetic information in the vast majority of eukaryotic species. The relatively high costs and technical challenges associated with the detection of DNA methylation however have created a bias in the number of methylation studies towards model organisms. Consequently, it remains challenging to infer kingdom-wide general rules about the functions and evolutionary conservation of DNA methylation. Methylated cytosine is often found in specific CpN dinucleotides, and the frequency distributions of, for instance, CpG observed/expected (CpG o/e) ratios have been used to infer DNA methylation types based on higher mutability of methylated CpG. RESULTS: Predominantly model-based approaches essentially founded on mixtures of Gaussian distributions are currently used to investigate questions related to the number and position of modes of CpG o/e ratios. These approaches require the selection of an appropriate criterion for determining the best model and will fail if empirical distributions are complex or even merely moderately skewed. We use a kernel density estimation (KDE) based technique for robust and precise characterization of complex CpN o/e distributions without a priori assumptions about the underlying distributions. CONCLUSIONS: We show that KDE delivers robust descriptions of CpN o/e distributions. For straightforward processing, we have developed a Galaxy tool, called Notos and available at the ToolShed, that calculates these ratios of input FASTA files and fits a density to their empirical distribution. Based on the estimated density the number and shape of modes of the distribution is determined, providing a rational for the prediction of the number and the types of different methylation classes. Notos is written in R and Perl.


Assuntos
Ilhas de CpG , Metilação de DNA/genética , Software , Jacarés e Crocodilos/genética , Animais , Citrus/genética , Análise por Conglomerados , Gafanhotos/genética , Humanos , Mariposas/genética , Neurospora crassa/genética
13.
Dev Comp Immunol ; 85: 31-43, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29574022

RESUMO

All jawed vertebrates have four T cell receptor (TCR) chains that are expressed by thymus-derived lymphocytes and play a major role in animal immune defence. However, few studies have investigated the TCR chains of crocodilians compared with those of birds and mammals, despite their key evolutionary position linking amphibians, reptiles, birds and mammals. Here, employing an Alligator sinensis genomic bacterial artificial chromosome (BAC) library and available genome data, we characterized the genomic organization, evolution and expression of TRB and TRG loci in Alligator sinensis. According to the sequencing data, the Alligator sinensis TRB locus spans approximately 500 Kb of genomic DNA containing two D-J-C clusters and 43 V gene segments and is organized as Vß(39)-pJß1-pCß1-pDß1-Dß2- Jß2(12)-Cß2-Vß(4), whereas the TRG locus spans 115 Kb of DNA genomic sequence consisting of 18 V gene segments, nine J gene segments and one C gene segment and is organized in a classical translocon pattern as Vγ(18)-Jγ(9)-Cγ. Moreover, syntenic analysis of TRB and TRG chain loci suggested a high degree of conserved synteny in the genomic regions across mammals, birds and Alligator sinensis. By analysing the cloned TRB/TRG cDNA, we identified the usage pattern of V families in the expressed TRB and TRG. An analysis of the junctions of the recombined VJ revealed the presence of N and P nucleotides in both expressed TRB and TRG sequences. Phylogenetic analysis revealed that TRB and TRG loci possess distinct evolutionary patterns. Most Alligator sinensis V subgroups have closely related orthologues in chicken and duck, and a small number of Alligator sinensis V subgroups have orthologues in mammals, which supports the hypothesis that crocodiles are the closest relatives of birds and mammals. Collectively, these data provide insights into TCR gene evolution in vertebrates and improve our understanding of the Alligator sinensis immune system.


Assuntos
Jacarés e Crocodilos/genética , Genes Codificadores dos Receptores de Linfócitos T/genética , Animais , Aves/genética , Cromossomos Artificiais Bacterianos/genética , DNA Complementar , Evolução Molecular , Genoma/genética , Genômica/métodos , Mamíferos/genética , Filogenia , Sintenia/genética
14.
Elife ; 72018 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-29565246

RESUMO

Mammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from which first mammals then birds independently evolved. Here, we studied the conduction system in crocodiles (Alligator mississippiensis), the only ectothermic vertebrates with a full ventricular septum. We identified homologues of mammalian conduction system markers (Tbx3-Tbx5, Scn5a, Gja5, Nppa-Nppb) and show the presence of a functional atrioventricular bundle. The ventricular Purkinje network, however, was absent and slow ventricular conduction relied on trabecular myocardium, as it does in other ectothermic vertebrates. We propose the evolution of the atrioventricular bundle followed full ventricular septum formation prior to the development of high heart rates and endothermy. In contrast, the evolution of the ventricular Purkinje network is strongly associated with high heart rates and endothermy.


Assuntos
Jacarés e Crocodilos/fisiologia , Sistema de Condução Cardíaco/fisiologia , Frequência Cardíaca/fisiologia , Coração/fisiologia , Jacarés e Crocodilos/embriologia , Jacarés e Crocodilos/genética , Animais , Fascículo Atrioventricular/embriologia , Fascículo Atrioventricular/metabolismo , Fascículo Atrioventricular/fisiologia , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Coração/embriologia , Sistema de Condução Cardíaco/embriologia , Frequência Cardíaca/genética , Ventrículos do Coração/embriologia , Ventrículos do Coração/metabolismo , Hibridização In Situ , Modelos Cardiovasculares , Ramos Subendocárdicos/embriologia , Ramos Subendocárdicos/metabolismo , Ramos Subendocárdicos/fisiologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Septo Interventricular/embriologia , Septo Interventricular/metabolismo , Septo Interventricular/fisiologia
15.
Curr Biol ; 28(5): 686-696.e6, 2018 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-29456143

RESUMO

The avian dorsal telencephalon has two vast territories, the nidopallium and the mesopallium, both of which have been shown to contribute substantially to higher cognitive functions. From their connections, these territories have been proposed as equivalent to mammalian neocortical layers 2 and 3, various neocortical association areas, or the amygdala, but whether these are analogies or homologies by descent is unknown. We investigated the molecular profiles of the mesopallium and the nidopallium with RNA-seq. Gene expression experiments established that the mesopallium, but not the nidopallium, shares a transcription factor network with the intratelencephalic class of neocortical neurons, which are found in neocortical layers 2, 3, 5, and 6. Experiments in alligators demonstrated that these neurons are also abundant in the crocodilian cortex and form a large mesopallium-like structure in the dorsal ventricular ridge. Together with previous work, these molecular findings indicate a homology by descent for neuronal cell types of the avian dorsal telencephalon with the major excitatory cell types of mammalian neocortical circuits: the layer 4 input neurons, the deep layer output neurons, and the multi-layer intratelencephalic association neurons. These data raise the interesting possibility that avian and primate lineages evolved higher cognitive abilities independently through parallel expansions of homologous cell populations.


Assuntos
Jacarés e Crocodilos/fisiologia , Galinhas/fisiologia , Neurônios/metabolismo , Prosencéfalo/fisiologia , Estorninhos/fisiologia , Jacarés e Crocodilos/genética , Animais , Proteínas Aviárias/metabolismo , Galinhas/genética , Regulação da Expressão Gênica/fisiologia , Neocórtex , Proteínas de Répteis/metabolismo , Estorninhos/genética , Fatores de Transcrição/metabolismo
16.
Genome Biol Evol ; 10(2): 694-704, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29447391

RESUMO

The epidermis of amniotes forms a protective barrier against the environment and the differentiation program of keratinocytes, the main cell type in the epidermis, has undergone specific alterations in the course of adaptation of amniotes to a broad variety of environments and lifestyles. The epidermal differentiation complex (EDC) is a cluster of genes expressed at late stages of keratinocyte differentiation in both sauropsids and mammals. In the present study, we identified and analyzed the crocodilian equivalent of the EDC. The gene complement of the EDC of both the American alligator and the saltwater crocodile were determined by comparative genomics, de novo gene prediction and identification of EDC transcripts in published transcriptome data. We found that crocodilians have an organization of the EDC similar to that of their closest living relatives, the birds, with which they form the clade Archosauria. Notable differences include the specific expansion of a subfamily of EDC genes in crocodilians and the loss of distinct ancestral EDC genes in birds. Identification and comparative analysis of crocodilian orthologs of avian feather proteins suggest that the latter evolved by cooption and sequence modification of ancestral EDC genes, and that the amplification of an internal highly cysteine-enriched amino acid sequence motif gave rise to the feather component epidermal differentiation cysteine-rich protein in the avian lineage. Thus, sequence diversification of EDC genes contributed to the evolutionary divergence of the crocodilian and avian integuments.


Assuntos
Jacarés e Crocodilos/genética , Evolução Biológica , Aves/genética , Epiderme , Plumas , Sequência de Aminoácidos , Animais , Sequência de Bases , Diferenciação Celular , Feminino , Sintenia , Tartarugas/genética
17.
Artigo em Inglês | MEDLINE | ID: mdl-29447579

RESUMO

The demand for crocodile meat is quickly growing because of its exotic and organoleptic appeal and also the low content of cholesterol and lipids. Moreover, crocodile oil and blood have been used in alternative medicines for treating asthma and several other ailments since ancient times. Furthermore, crocodile hides have great demand in leather industries. All of these have collectively contributed to the extensive hunting, illegal trading and consequent decline of crocodiles in most parts of the world. To keep space with the growing demands, some crocodile species such as Crocodylus porosus have been raised in farms and its commercial trades have been legalised. However, demand for wild crocodiles in foods and medicines has continued in high gear. Recently, several DNA-based methods have been proposed for crocodile detection, but those assays are based on single gene and longer-sized amplicon targets that break down during extensive processing. To address this gap, here we developed and validated a highly stable double gene targeted multiplex PCR assay for the identification of C. porosus materials in commercial products. The assay involved two short sites from C. porosus atp6 (77 bp) and cytb (127 bp) genes and a universal internal control (99 bp) for eukaryotes. The PCR primers were cross-tested against 18 species and validated under pure and mixed matrices under extensive boiling, autoclaving and microwave cooking conditions. Finally, it was used to identify five crocodile-based commercial products. The lower limits of detection for atp6 and cytb genes were 0.001 ng and 0.01 ng DNA, respectively, in pure meat and 1% under mixed matrices. Some inherent features, such as 77-127 bp amplicon sizes, exceptional stability and superior sensitivity, suggested the assay could be used for the identification of C. porosus in any forensic specimen.


Assuntos
Jacarés e Crocodilos/genética , Citocromos b/genética , Carne/análise , ATPases Mitocondriais Próton-Translocadoras/genética , Reação em Cadeia da Polimerase , Animais , Citocromos b/metabolismo , Análise de Alimentos , Contaminação de Alimentos , ATPases Mitocondriais Próton-Translocadoras/metabolismo
18.
Dev Comp Immunol ; 81: 193-203, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29203331

RESUMO

The ß-defensin, one of the antimicrobial peptides (AMPs), is a significant component of the innate immune with a broad range of antimicrobial activities. Differing from the widely-studied mammals and birds, limited information about ß-defensins has been reported in reptiles, especially in crocodilians. As a same ancient species as dinosaurs and the most endangered species of 23 crocodilians, the survival of Chinese alligator (Alligator sinensis) means a powerful immune system and possible involvement of AMPs in its immune resistance. In this study, we identified 20 novel Alligator sinensisß-defensin genes (AsBDs) from a 390 kb region using bioinformatic and experimental approaches, and successfully distinguished six orthologous AsBDs to birds and nine paralogous AsBDs undergoing gene duplication events. The amino acid alignment shows that the AsBD paralogs, like α-defensins, encode a significantly longer pro-piece comparing with the orthologs. The calculation of non-synonymous (dN) and synonymous (dS) substitutions in the mature peptide reveals that the AsBD paralogs experience a significantly higher selective pressure (dN/dS) than the orthologs, but a similar evolutionary force to α-defensins. The gene expression result indicates that the AsBD paralogs have a significantly higher expression level than the orthologos in gastrointestinal tract where the host is vulnerable to enteric pathogenic bacteria, as observed in α-defensins. These three pieces of evidence demonstrate that the AsBD paralogs do play an important role in maintaining long-term survival of this endangered reptile. Thus, this survey of AsBDs on the genomic structure, evolutionary characteristics, and expression pattern provides a genetic and immunological foundation for further investigating their antimicrobial function and alternative antibiotics potentiality.


Assuntos
Jacarés e Crocodilos/genética , Peptídeos Catiônicos Antimicrobianos/genética , Imunidade Inata/genética , beta-Defensinas/genética , Jacarés e Crocodilos/imunologia , Animais , Peptídeos Catiônicos Antimicrobianos/metabolismo , Biologia Computacional , Evolução Molecular , Duplicação Gênica , Família Multigênica/genética , Filogenia , Especificidade da Espécie , Transcriptoma , beta-Defensinas/metabolismo
19.
Anim Reprod Sci ; 187: 124-132, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29103625

RESUMO

The Chinese alligator Alligator sinensis is a critically endangered species endemic to China. Knowledge about reproductive strategies of a species contributes to their conservation. Little is, however, known about the reproductive strategies and its impact on the population. In the present study, an easy and non-invasive genetic method was used to improve the understanding of mating system of Chinese alligators and its effect on the population genetic diversity by nine polymorphic microsatellite loci. There was a high incidence of multiple paternity among 50 clutches, with a total 60% of the clutches having multiple paternity and up to three males contributing to single clutches. In addition, polyandry females choose to mate with males that are more distant in relatedness compared with monogamy females. Multiple paternity can decrease the inbreeding coefficient, while there is no significant difference between single and multiple paternity (P>0.05). Furthermore, there was an increased allelic diversity (though not heterozygosity) in multiple paternity sired offspring compared with the single paternity sired offspring in F2 generations (P<0.05), as predicted by the genetic diversity hypothesis. Multiple paternity may function as an important inbreeding avoidance compensation mechanism leading to the potential of the species to avoid extinction. These findings will not only enhance the understanding of the mating system and the biological traits of the Chinese alligator, but also improve the captive breeding program management and conservation strategies of the endangered species.


Assuntos
Jacarés e Crocodilos/fisiologia , Comportamento Sexual Animal/fisiologia , Alelos , Jacarés e Crocodilos/genética , Animais , China , Espécies em Perigo de Extinção , Feminino , Variação Genética , Endogamia , Masculino , Repetições de Microssatélites , Reprodução
20.
Proc Natl Acad Sci U S A ; 114(50): 13164-13169, 2017 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-29109249

RESUMO

Zooarchaeologists have long relied on linear traces and pits found on the surfaces of ancient bones to infer ancient hominid behaviors such as slicing, chopping, and percussive actions during butchery of mammal carcasses. However, such claims about Plio-Pleistocene hominids rely mostly on very small assemblages of bony remains. Furthermore, recent experiments on trampling animals and biting crocodiles have shown each to be capable of producing mimics of such marks. This equifinality-the creation of similar products by different processes-makes deciphering early archaeological bone assemblages difficult. Bone modifications among Ethiopian Plio-Pleistocene hominid and faunal remains at Asa Issie, Maka, Hadar, and Bouri were reassessed in light of these findings. The results show that crocodiles were important modifiers of these bone assemblages. The relative roles of hominids, mammalian carnivores, and crocodiles in the formation of Oldowan zooarchaeological assemblages will only be accurately revealed by better bounding equifinality. Critical analysis within a consilience-based approach is identified as the pathway forward. More experimental studies and increased archaeological fieldwork aimed at generating adequate samples are now required.


Assuntos
Jacarés e Crocodilos/anatomia & histologia , Mordeduras e Picadas/patologia , Osso e Ossos/lesões , Fósseis/anatomia & histologia , Hominidae/anatomia & histologia , África , Jacarés e Crocodilos/genética , Jacarés e Crocodilos/fisiologia , Animais , Evolução Biológica , Hominidae/genética , Hominidae/fisiologia , Dente/anatomia & histologia
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