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1.
Rev Environ Contam Toxicol ; 249: 133-152, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30879139

RESUMO

Mercury (Hg) is an environmental contaminant that has been reported in many wildlife species worldwide. The organic form of Hg bioaccumulates in higher trophic levels, and thus, long-lived predators are at risk for higher Hg exposure. Although ecological risk assessments for contaminants such as Hg include pertinent receptor species, snakes are rarely considered, despite their high trophic status and potential to accumulate high levels of Hg. Our current knowledge of these reptiles suggests that snakes may be useful novel biomarkers to monitor contaminated environments. The few available studies show that snakes can bioaccumulate significant amounts of Hg. However, little is known about the role of snakes in Hg transport in the environment or the individual-level effects of Hg exposure in this group of reptiles. This is a major concern, as snakes often serve as important prey for a variety of taxa within ecosystems (including humans). In this review, we compiled and analyzed the results of over 30 studies to discuss the impact of Hg on snakes, specifically sources of exposure, bioaccumulation, health consequences, and specific scientific knowledge gaps regarding these moderate to high trophic predators.


Assuntos
Monitoramento Ambiental , Mercúrio/metabolismo , Serpentes/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Biomarcadores/metabolismo , Ecossistema , Humanos
2.
J Photochem Photobiol B ; 197: 111538, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31247385

RESUMO

The effects of topically administered snake (Deinagkistrodon acutus) oil and its main fatty acid components on skin photodamage were explored. Epidermal thickness, mice body weight, antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase), inflammatory cytokines (tumor necrosis factor alpha and interleukin-6), skin histology, collagen content, and metalloproteinase-1 indicators were analyzed. The results show that topical application of both snake oil and its main fatty acids recovered ultraviolet B (UVB) irradiation induced antioxidant enzymes depletion, prevented metalloproteinase-1. Snake oil and its main fatty acids suppressed dermal infiltration of inflammatory cells and reduced inflammatory cytokines levels. Notably, there was no significant difference in the antioxidant activity but a significant difference in the anti-inflammatory activity between fatty acids and snake oil under the same dose. Finally, snake oil and its main fatty acids inhibited UVB-induced histological damage such as epidermal thickening, collagen fiber and elastic fiber destruction. Our study demonstrated for the first time in KM mice that snake oil exhibited prominent photoprotection activity by protecting the activity of antioxidant enzymes and inhibiting inflammatory factors, as well as reducing the generation of MMP-1. What's more, the main fatty acids in snake oil play an important role in preventing photo-damage especially in protecting antioxidant enzyme activity.


Assuntos
Anti-Inflamatórios/farmacologia , Ácidos Graxos/farmacologia , Óleos Voláteis/química , Pele/efeitos dos fármacos , Serpentes/metabolismo , Raios Ultravioleta , Animais , Anti-Inflamatórios/química , Antioxidantes/metabolismo , Catalase/metabolismo , Citocinas/metabolismo , Epiderme/fisiologia , Ácidos Graxos/química , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Glutationa Peroxidase/metabolismo , Hidroxiprolina/análise , Interleucina-6/genética , Interleucina-6/metabolismo , Metaloproteinase 1 da Matriz/metabolismo , Camundongos , Pele/metabolismo , Pele/patologia , Pele/efeitos da radiação , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo
3.
Mater Sci Eng C Mater Biol Appl ; 100: 23-29, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948057

RESUMO

Emulsions are crucial in the treatment of snake bites to bust the antibody response of the inmunogen. The widely used Freund's emulsion typically combines 50/50 water-oil (W/O) phase. However, its use is limited because it is associated with tissue damage. We formulated and characterized a Pickering Emulsion 70/30 (W/O) that uses a chemically modified hydrophobic hydroxyapatite as surfactant. This Pickering emulsion has similar rheologic behavior to Freund's emulsion 50/50, but with lower oil and surfactant concentration. Evaluation of cell recruitment, antibody response and adhering tissue in mice immunized with B. asper of Pacific venom and treated with Freund's and Pickering 70/30 emulsions resulted in similar adjuvant activity (only 18% lower in Pickering 70/30 emulsion). However, Pickering 70/30 emulsions minimized negative side effects in the host animals and showed better ease of flow that favors injection of the host. Our results open up room for optimization and improvement of Pickering emulsion based on modified nanoparticles for medical applications.


Assuntos
Adjuvantes Imunológicos/química , Anticorpos/metabolismo , Durapatita/química , Emulsões/química , Nanopartículas/química , Venenos de Serpentes/imunologia , Animais , Camundongos , Venenos de Serpentes/química , Serpentes/metabolismo , Tensoativos/química
4.
Pharmazie ; 74(3): 136-141, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30961677

RESUMO

In a previous study, it was shown, that shed snake skin is a good alternative model membrane for the human stratum corneum (SC). In this study, the influence of the enhancers dimethyl sulfoxide (DMSO), 1,2-propanediol, 1,3-butanediol, 1,2-pentanediol, 1,2-hexanediol and 1,2-octanediol in a concentration of 10 % on the permeation of l-prolyl- l-lysyl-l-α-glutamyl-l-lysin (PKEK) through shed snake skin was conducted. Pharmacokinetic parameters (diffusion coefficient, permeation coefficient, t-lag, Flux) were calculated. All examinations were performed on the skin of an individual and thus allowed a very good comparability of the data. All enhancers have overcome the shed snake skin and could be proven in the acceptor. DMSO does not affect the permeability of the membrane. Nevertheless, PKEK permeates faster in the presence of DMSO than PKEK being used alone. PKEK permeated the same, no matter if an auxiliary material was added or not. Without their addition, in all other enhancers no significant difference towards permeation could be determined.


Assuntos
Portadores de Fármacos/administração & dosagem , Oligopeptídeos/administração & dosagem , Oligopeptídeos/farmacocinética , Pele/efeitos dos fármacos , Pele/metabolismo , Serpentes/metabolismo , Administração Cutânea , Animais , Butileno Glicóis/farmacologia , Coloides/administração & dosagem , Difusão , Dimetil Sulfóxido/farmacologia , Portadores de Fármacos/química , Composição de Medicamentos , Glicóis/farmacologia , Hexanos/farmacologia , Modelos Animais , Octanóis/farmacologia , Oligopeptídeos/química , Pentanos/farmacologia , Permeabilidade/efeitos dos fármacos , Propilenoglicol/farmacologia , Absorção Cutânea/efeitos dos fármacos , Tensoativos/administração & dosagem , Tensoativos/química , Tensoativos/farmacocinética
5.
Methods Mol Biol ; 1855: 23-29, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30426403

RESUMO

This chapter briefly discusses the developments in electrophoresis of proteins from Tiselius' moving-boundary electrophoresis to the modern-day two-dimensional polyacrylamide gel electrophoresis. It also touches upon the staining methods used to visualize total proteins post electrophoresis.


Assuntos
Eletroforese/métodos , Venenos de Serpentes/análise , Serpentes/metabolismo , Animais , Eletroforese Capilar , Eletroforese em Gel Bidimensional , Focalização Isoelétrica
6.
Environ Pollut ; 241: 1063-1070, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30029314

RESUMO

Dichlorodiphenyltrichloroethanes (DDTs), Polychlorinated biphenyls (PCBs), and halogenated flame retardants (HFRs) were measured in aquatic, amphibious, and terrestrial wildlife collected from an e-waste contaminated pond and its surrounding region. The species-specific bioaccumulation and maternal transfer of chemicals in the watersnake were investigated. Total concentrations of target chemicals ranged from 1.3 × 103 to 4.8 × 105 ng g-1 lipid weight. PCBs were the predominant (72-95%) contaminants, followed by polybrominated biphenyl ethers (PBDEs, 4-27%). The concentrations of PCBs and HFRs except decabromodiphenyl ethane (DBDPE) were higher in aquatic organisms and terrestrial birds than in amphibians and lizards. Relatively high DDT levels were observed in the terrestrial birds and toads, but high DBDPE was found in the aquatic species except for waterbird eggs. Species-specific congeners profiles for PCB and PBDE and isomeric composition for dechlorane plus were observed. These results indicated a habitat-dependent accumulation among different species. Maternal transfer examined by the ratio of egg to carcass for watersnakes indicated multi-linear correlations between maternal transfer potential and octanol-water partition coefficient (log KOW) of chemicals. The same maternal transfer efficiencies were found for chemicals with log KOW between 6 and 8, then the maternal transfer potential rapidly decreased with increasing of log KOW.


Assuntos
Resíduo Eletrônico , Monitoramento Ambiental , Compostos Orgânicos/metabolismo , Serpentes/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Organismos Aquáticos , Aves , Bromobenzenos , China , Ecossistema , Ovos/análise , Feminino , Retardadores de Chama/análise , Retardadores de Chama/metabolismo , Cadeia Alimentar , Éteres Difenil Halogenados/análise , Halogenação , Hidrocarbonetos Clorados , Exposição Materna , Compostos Orgânicos/análise , Bifenilos Policlorados/análise , Bifenilos Policlorados/metabolismo , Compostos Policíclicos , Poluentes Químicos da Água/análise
7.
Zoology (Jena) ; 126: 145-153, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29129393

RESUMO

Corneous beta-proteins (CBPs), formerly referred to as beta-keratins, are major protein components of the epidermis in lepidosaurian reptiles and are largely responsible for their material properties. These proteins have been suggested to form filaments of 3.4nm in thickness and to interact with themselves or with other proteins, including intermediate filament (IF) keratins. Here, we performed immunocytochemical labeling of CBPs in the epidermis of different lizards and snakes and investigated by immunoblotting analysis whether the reduction of disulfide bonds or protein oxidation affects the solubility and mobility of these CBPs. Immunogold labeling suggested that CBPs are partly co-localized with IF-keratins in differentiating and mature beta-cells. The chemical reduction of epidermal proteins from lizard and snake epidermis increased the abundance of CBP-immunoreactive bands in the size range of CBP monomers on Western blots. Conversely, in vitro oxidation of epidermal proteins reduced the abundance of putative CBP monomers. Some modifications in the IF-keratin range were also noted. These results strongly indicate that CBPs associate with IF-keratins and other proteins via disulfide bonds in the epidermis of lizards and snakes, which likely contributes to the resilience of the cornified beta- and alpha-layers of the lepidosaurian epidermis in live animals and after shedding.


Assuntos
Epiderme/metabolismo , Lagartos/metabolismo , Serpentes/metabolismo , beta-Queratinas/metabolismo , Animais , Western Blotting , Dissulfetos/metabolismo , Eletroforese em Gel de Poliacrilamida , Epiderme/anatomia & histologia , Epiderme/ultraestrutura , Lagartos/anatomia & histologia , Microscopia , Oxirredução , Serpentes/anatomia & histologia
8.
Curr Med Chem ; 24(17): 1874-1891, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28578650

RESUMO

Snakes are fascinating creatures and have been residents of this planet well before ancient humans dwelled the earth. Venomous snakes have been a figure of fear, and cause notable mortality throughout the world. The venom constitutes families of proteins and peptides with various isoforms that make it a cocktail of diverse molecules. These biomolecules are responsible for the disturbance in fundamental physiological systems of the envenomed victim, leading to morbidity which can lead to death if left untreated. Researchers have turned these life-threatening toxins into life-saving therapeutics via technological advancements. Since the development of captopril, the first drug that was derived from bradykininpotentiating peptide of Bothrops jararaca, to the disintegrins that have potent activity against certain types of cancers, snake venom components have shown great potential for the development of lead compounds for new drugs. There is a continuous development of new drugs from snake venom for coagulopathy and hemostasis to anti-cancer agents. In this review, we have focused on different snake venom proteins / peptides derived drugs that are in clinical use or in developmental stages till to date. Also, some commonly used snake venom derived diagnostic tools along with the recent updates in this exciting field are discussed.


Assuntos
Venenos de Serpentes/química , Animais , Anticoagulantes/química , Anticoagulantes/metabolismo , Anticoagulantes/uso terapêutico , Batroxobina/química , Batroxobina/uso terapêutico , Coagulação Sanguínea/efeitos dos fármacos , Captopril/química , Captopril/uso terapêutico , Peptídeos/metabolismo , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Venenos de Serpentes/metabolismo , Serpentes/metabolismo , Trombose/tratamento farmacológico , Trombose/patologia , Tirofibana , Toxinas Biológicas/metabolismo , Toxinas Biológicas/farmacologia , Toxinas Biológicas/uso terapêutico , Tirosina/análogos & derivados , Tirosina/química , Tirosina/uso terapêutico
9.
Curr Med Chem ; 24(17): 1892-1908, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28571558

RESUMO

The Pseudechis colletti and Pseudechis butleri venoms were analyzed by 1-D gel electrophoresis, followed by mass spectrometric analysis of tryptic peptides obtained from the protein bands. Both venoms contain highly potent pharmacologically active components, which were assigned to the following protein families: basic and acidic phospholipases A2 (PLA2s), L-amino acid oxidases (LAAOs), P-III metalloproteinases (P-III SVMPs), 5'- nucleotidases (5'-NTDs), cysteine-rich secretory proteins (CRISPs), venom nerve growth factors (VNGFs) and post-synaptic neurotoxins. Considerable predominance of PLA2s over other toxins is a characteristic feature of both venoms. The major differences in the venom compositions are the higher concentration of SVMPs and CRISPs in the P. butleri venom, as well as the presence of post-synaptic neurotoxins. Furthermore, the analysis revealed a high concentration of proteins with myotoxic, coagulopathic and apoptotic activities. PLA2s are responsible for the myotoxic and anticoagulant effects observed in patients after envenomation (4). The other protein families, encountered in the two venoms, probably contribute to the major symptoms described for these venoms. These results explain the observed clinical effects of the black snake envenomation. The analyzed venoms contain group P-III metalloproteinases of medical importance with the potency to be used for diagnostic purposes of von Willebrand factor (vWF) disease, for regulation of vWF in thrombosis and haemostasis, for studying the function of the complement system in host defense and in the pathogenesis of diseases. Comparison of venomic data showed similarities in the major venom components of snakes from the genus Pseudechis, resulting in common clinical effects of envenomation, and demonstrating close relationships between venom toxins of Elapidae snakes.


Assuntos
Peptídeos/análise , Proteoma/análise , Venenos de Serpentes/metabolismo , Serpentes/metabolismo , Aminoácido Oxirredutases/análise , Aminoácido Oxirredutases/metabolismo , Animais , Austrália , Eletroforese em Gel de Poliacrilamida , Metaloendopeptidases/análise , Metaloendopeptidases/metabolismo , Fatores de Crescimento Neural/análise , Fatores de Crescimento Neural/metabolismo , Peptídeos/metabolismo , Fosfolipases A2/análise , Fosfolipases A2/metabolismo , Espectrometria de Massas em Tandem
10.
Sci Rep ; 7: 43556, 2017 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-28368001

RESUMO

Snake gallbladder, a traditional Chinese medicine, has been believed in various Asian countries to improve visual acuity and alleviate rheumatism. Bile acids, a major component of the gallbladder, are toxic to the liver and kidney in humans and animals due to its detergent effects, while also exhibiting therapeutic effects due to an increase in the gallbladder contractions of muscle strips in patients with cholesterol gallstones. Secretion of bile acids in human and mammals depends on the bile salt export pump (BSEP), a liver-specific adenosine triphosphate (ATP)-binding cassette transporter encoded by ABCB11. However, the presence of BSEP in snakes has not been thoroughly explored. Here we confirm the existence of BSEP and its coding DNA sequence in snakes on both the proteomic and genetic level. This work provides information on the snake ABCB11 sequence and helps further potential genetic manipulation to affect bile salt metabolism. Our study provides the foundation for research on bile acid production from snakes by using modern genetic and proteomic methodologies.


Assuntos
Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/metabolismo , Genômica , Fígado/metabolismo , Proteômica , Serpentes/genética , Serpentes/metabolismo , Animais , Genômica/métodos , Filogenia , Proteômica/métodos , Análise de Sequência de DNA , Serpentes/classificação
11.
Arch Environ Contam Toxicol ; 72(4): 586-595, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28424837

RESUMO

Top trophic level predators are at risk from bioaccumulation of heavy metals from their prey. Using nondestructively collected tissues as a method of assessing metal concentrations in snakes is useful for populations that are threatened or declining. This paper reports concentrations of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) in tissues of Northern pine snakes (Pituophis melanoleucus) from the New Jersey Pine Barrens, a relatively pristine, undisturbed habitat. We also determined if skin is an appropriate indicator of internal concentrations and identified the factors (tissue, year of collection, length, sex) that might explain variations in metal concentrations. Because they can grow to 2-m long and live for 25 years, we suggest that these snakes might accumulate heavy metals. Multiple regression models were significant, explaining 16% (lead) to 61% (mercury) of variation by tissue type. For mercury and chromium, size also was significant. The highest concentrations were in liver and kidney for all metals, except chromium and lead. Mercury concentrations in tissues were within the range reported for other snakes and were below effects concentrations in reptiles. The concentrations in skin were correlated with all internal tissues for mercury and for all internal tissues except heart for cadmium. These data show that shed skin can be used as an indicator of metals in pine snakes and that, at present, concentrations of heavy metals in this population are within the range of those found in other snake species from uncontaminated sites.


Assuntos
Monitoramento Ambiental , Metais Pesados/metabolismo , Serpentes/metabolismo , Animais , Arsênico/metabolismo , Cádmio/metabolismo , Cromo/metabolismo , Ecossistema , Mercúrio/metabolismo , New Jersey , Pinus , Selênio/metabolismo
12.
Sci Rep ; 7: 45338, 2017 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-28345630

RESUMO

The epidermis of snakes efficiently protects against dehydration and mechanical stress. However, only few proteins of the epidermal barrier to the environment have so far been identified in snakes. Here, we determined the organization of the Epidermal Differentiation Complex (EDC), a cluster of genes encoding protein constituents of cornified epidermal structures, in snakes and compared it to the EDCs of other squamates and non-squamate reptiles. The EDC of snakes displays shared synteny with that of the green anole lizard, including the presence of a cluster of corneous beta-protein (CBP)/beta-keratin genes. We found that a unique CBP comprising 4 putative beta-sheets and multiple cysteine-rich EDC proteins are conserved in all snakes and other squamates investigated. Comparative genomics of squamates suggests that the evolution of snakes was associated with a gene duplication generating two isoforms of the S100 fused-type protein, scaffoldin, the origin of distinct snake-specific EDC genes, and the loss of other genes that were present in the EDC of the last common ancestor of snakes and lizards. Taken together, our results provide new insights into the evolution of the skin in squamates and a basis for the characterization of the molecular composition of the epidermis in snakes.


Assuntos
Diferenciação Celular/genética , Epiderme/metabolismo , Serpentes/metabolismo , Animais , Evolução Biológica , Duplicação Gênica/genética , Genômica/métodos , Queratinas/genética , Queratinas/metabolismo , Lagartos/genética , Lagartos/metabolismo , Proteínas de Répteis/genética , Proteínas de Répteis/metabolismo , Serpentes/genética
13.
Toxins (Basel) ; 8(9)2016 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-27618098

RESUMO

The "function debate" in the philosophy of biology and the "venom debate" in the science of toxinology are conceptually related. Venom systems are complex multifunctional traits that have evolved independently numerous times throughout the animal kingdom. No single concept of function, amongst those popularly defended, appears adequate to describe these systems in all their evolutionary contexts and extant variations. As such, a pluralistic view of function, previously defended by some philosophers of biology, is most appropriate. Venom systems, like many other functional traits, exist in nature as points on a continuum and the boundaries between "venomous" and "non-venomous" species may not always be clearly defined. This paper includes a brief overview of the concept of function, followed by in-depth discussion of its application to venom systems. A sound understanding of function may aid in moving the venom debate forward. Similarly, consideration of a complex functional trait such as venom may be of interest to philosophers of biology.


Assuntos
Evolução Molecular , Modelos Biológicos , Filosofia , Serpentes/fisiologia , Toxicologia , Peçonhas , Adaptação Fisiológica , Animais , Genótipo , Humanos , Fenótipo , Mordeduras de Serpentes/metabolismo , Mordeduras de Serpentes/patologia , Serpentes/genética , Serpentes/metabolismo , Peçonhas/genética , Peçonhas/metabolismo , Peçonhas/toxicidade
14.
Dev Cell ; 38(3): 224-6, 2016 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-27505413

RESUMO

The vertebrate axial skeleton comprises regions of specialized vertebrae, which vary in length between lineages. Aires et al. (2016) uncover a key role for Oct4 in determining trunk length in mice. Additionally, a heterochronic shift in Oct4 expression may underlie the extreme elongation of the trunk in snakes.


Assuntos
Evolução Biológica , Osso e Ossos/metabolismo , Camundongos/anatomia & histologia , Fatores de Transcrição de Octâmero/metabolismo , Serpentes/anatomia & histologia , Tronco/anatomia & histologia , Animais , Camundongos/metabolismo , Serpentes/metabolismo
15.
Toxins (Basel) ; 8(6)2016 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-27294958

RESUMO

Snake venom metalloproteinases (SVMPs) are abundant in the venoms of vipers and rattlesnakes, playing important roles for the snake adaptation to different environments, and are related to most of the pathological effects of these venoms in human victims. The effectiveness of SVMPs is greatly due to their functional diversity, targeting important physiological proteins or receptors in different tissues and in the coagulation system. Functional diversity is often related to the genetic diversification of the snake venom. In this review, we discuss some published evidence that posit that processing and post-translational modifications are great contributors for the generation of functional diversity and for maintaining latency or inactivation of enzymes belonging to this relevant family of venom toxins.


Assuntos
Metaloproteases/química , Metaloproteases/genética , Processamento de Proteína Pós-Traducional , Venenos de Serpentes/enzimologia , Adaptação Biológica , Animais , Domínio Catalítico , Estabilidade Enzimática , Proteólise , Serpentes/metabolismo , Serpentes/fisiologia
16.
Dalton Trans ; 45(13): 5629-39, 2016 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-26923149

RESUMO

Polyhistidine-tags are often used for the affinity purification of polyhistidine-tagged recombinant proteins. These sequences are also found in nature and are often highly conserved across different species. However, their exact role in the biological systems is not clear. The purpose of this work is to shed light on the behavior of poly-His sequences in their interactions with metal ions. This work illustrates the first study of novel poly-(His-Ala) peptides that bind Cu(ii) applying both experimental techniques and extensive computational tools. The studied novel peptides are analogues of the short protected fragment of the pHpG (EDDH9GVG10) peptide, which was found in the venom of Atheris squamigera. Our study presents the properties of metal ion binding-histidine tag complexes and their mutated derivatives. The Cu(ii) binding ability in pHG (Ac-EDDH9G-NH2) is more efficient than in the mutated derivatives, although the number of imidazoles that bind to Cu(ii) ions are similar. Finally, the formation of an α-helical structure is observed in pHG and in one of the mutated derivatives, indicating the importance of the sequence in the poly-(His-Ala) tags.


Assuntos
Cobre/metabolismo , Peptídeos/metabolismo , Sequência de Aminoácidos , Animais , Dicroísmo Circular , Cobre/química , Histidina/genética , Histidina/metabolismo , Concentração de Íons de Hidrogênio , Íons/química , Simulação de Dinâmica Molecular , Mutação , Peptídeos/síntese química , Peptídeos/química , Potenciometria , Ligação Proteica , Venenos de Serpentes/metabolismo , Serpentes/metabolismo , Espectrofotometria Ultravioleta
17.
Sci Adv ; 2(6): e1600708, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-28439533

RESUMO

Most mammals, birds, and reptiles are readily recognized by their hairs, feathers, and scales, respectively. However, the lack of fossil intermediate forms between scales and hairs and substantial differences in their morphogenesis and protein composition have fueled the controversy pertaining to their potential common ancestry for decades. Central to this debate is the apparent lack of an "anatomical placode" (that is, a local epidermal thickening characteristic of feathers' and hairs' early morphogenesis) in reptile scale development. Hence, scenarios have been proposed for the independent development of the anatomical placode in birds and mammals and parallel co-option of similar signaling pathways for their morphogenesis. Using histological and molecular techniques on developmental series of crocodiles and snakes, as well as of unique wild-type and EDA (ectodysplasin A)-deficient scaleless mutant lizards, we show for the first time that reptiles, including crocodiles and squamates, develop all the characteristics of an anatomical placode: columnar cells with reduced proliferation rate, as well as canonical spatial expression of placode and underlying dermal molecular markers. These results reveal a new evolutionary scenario where hairs, feathers, and scales of extant species are homologous structures inherited, with modification, from their shared reptilian ancestor's skin appendages already characterized by an anatomical placode and associated signaling molecules.


Assuntos
Jacarés e Crocodilos/anatomia & histologia , Evolução Biológica , Morfogênese , Pele/anatomia & histologia , Serpentes/anatomia & histologia , Jacarés e Crocodilos/metabolismo , Animais , Aves/anatomia & histologia , Aves/metabolismo , Plumas/química , Plumas/metabolismo , Fósseis/anatomia & histologia , Mamíferos/anatomia & histologia , Mamíferos/metabolismo , Proteínas/metabolismo , Transdução de Sinais , Pele/metabolismo , Serpentes/metabolismo
18.
J Comp Neurol ; 524(1): 74-89, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26053997

RESUMO

Retinal progenitors in the circumferential marginal zone (CMZ) and Müller glia-derived progenitors have been well described for the eyes of fish, amphibians, and birds. However, there is no information regarding a CMZ and the nature of retinal glia in species phylogenetically bridging amphibians and birds. The purpose of this study was to examine the retinal glia and investigate whether a CMZ is present in the eyes of reptilian species. We used immunohistochemical analyses to study retinal glia, neurons that could influence CMZ progenitors, the retinal margin, and the nonpigmented epithelium of ciliary body of garter snakes, queen snakes, anole lizards, snapping turtles, and painted turtles. We compare our observations on reptile eyes to the CMZ and glia of fish, amphibians, and birds. In all species, Sox9, Pax6, and the glucocorticoid receptor are expressed by Müller glia and cells at the retinal margin. However, proliferating cells were found only in the CMZ of turtles and not in the eyes of anoles and snakes. Similar to eyes of chickens, the retinal margin in turtles contains accumulations of GLP1/glucagonergic neurites. We find that filamentous proteins, vimentin and GFAP, are expressed by Müller glia, but have different patterns of subcellular localization in the different species of reptiles. We provide evidence that the reptile retina may contain nonastrocytic inner retinal glial cells, similar to those described in the avian retina. We conclude that the retinal glia, glucagonergic neurons, and CMZ of turtles appear to be most similar to those of fish, amphibians, and birds.


Assuntos
Glucagon/metabolismo , Lagartos/anatomia & histologia , Neuroglia/citologia , Retina/citologia , Serpentes/anatomia & histologia , Tartarugas/anatomia & histologia , Anfíbios/anatomia & histologia , Anfíbios/metabolismo , Animais , Proliferação de Células , Galinhas/anatomia & histologia , Galinhas/metabolismo , Feminino , Peixes/anatomia & histologia , Peixes/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Lagartos/metabolismo , Masculino , Neuroglia/metabolismo , Retina/metabolismo , Serpentes/metabolismo , Especificidade da Espécie , Tartarugas/metabolismo
19.
Toxicon ; 108: 19-31, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26410112

RESUMO

Philodryas chamissonis is a rear-fanged snake endemic to Chile. Its bite produces mild to moderate symptoms with proteolytic and anti-coagulant effects. Presently, the composition of the venom, as well as, the biochemical and structural characteristics of its toxins, remains unknown. In this study, we cloned and reported the first full-length sequences of five toxin-encoding genes from the venom gland of this species: Type III snake venom metalloprotease (SVMP), snake venom serine protease (SVSP), Cysteine-rich secretory protein (CRISP), α and ß subunits of C-type lectin-like protein (CLP) and C-type natriuretic peptide (NP). These genes are highly expressed in the venom gland and their sequences exhibited a putative signal peptide, suggesting that these are components of the venom. These putative toxins had different evolutionary relationships with those reported for some front-fanged snakes, being SVMP, SVSP and CRISP of P. chamissonis closely related to the toxins present in Elapidae species, while NP was more related to those of Viperidae species. In addition, analyses suggest that the α and ß subunits of CLP of P. chamissonis might have a α-subunit scaffold in common with Viperidae species, whose highly variable C-terminal region might have allowed the diversification in α and ß subunits. Our results provide the first molecular description of the toxins possibly implicated in the envenomation of prey and humans by the bite of P. chamissonis.


Assuntos
Venenos de Serpentes/química , Sequência de Aminoácidos , Animais , Clonagem Molecular , Camundongos , Estrutura Terciária de Proteína , Alinhamento de Sequência , Análise de Sequência de DNA , Análise de Sequência de Proteína , Venenos de Serpentes/genética , Venenos de Serpentes/toxicidade , Serpentes/genética , Serpentes/metabolismo
20.
G3 (Bethesda) ; 5(11): 2375-82, 2015 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-26358130

RESUMO

Protein expression is a major link in the genotype-phenotype relationship, and processes affecting protein abundances, such as rates of transcription and translation, could contribute to phenotypic evolution if they generate heritable variation. Recent work has suggested that mRNA abundances do not accurately predict final protein abundances, which would imply that post-transcriptional regulatory processes contribute significantly to phenotypes. Post-transcriptional processes also appear to buffer changes in transcriptional patterns as species diverge, suggesting that the transcriptional changes have little or no effect on the phenotypes undergoing study. We tested for concordance between mRNA and protein expression levels in snake venoms by means of mRNA-seq and quantitative mass spectrometry for 11 snakes representing 10 species, six genera, and three families. In contrast to most previous work, we found high correlations between venom gland transcriptomes and venom proteomes for 10 of our 11 comparisons. We tested for protein-level buffering of transcriptional changes during species divergence by comparing the difference between transcript abundance and protein abundance for three pairs of species and one intraspecific pair. We found no evidence for buffering during divergence of our three species pairs but did find evidence for protein-level buffering for our single intraspecific comparison, suggesting that buffering, if present, was a transient phenomenon in venom divergence. Our results demonstrated that post-transcriptional mechanisms did not contribute significantly to phenotypic evolution in venoms and suggest a more prominent and direct role for cis-regulatory evolution in phenotypic variation, particularly for snake venoms.


Assuntos
Variação Genética , Fenótipo , Processamento Pós-Transcricional do RNA , Venenos de Serpentes/genética , Transcriptoma , Animais , Especiação Genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Venenos de Serpentes/química , Venenos de Serpentes/metabolismo , Serpentes/genética , Serpentes/metabolismo
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