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1.
Brain Behav Immun ; 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31931152

RESUMO

Parkinson's disease (PD) is one of the most significant medical and social burdens of our time. The prevalence of PD increases with age and the number of individuals diagnosed with PD is expected to double from 6.9 million in 2015 to 14.2 million in 2040. To date, no drugs can stop the ongoing neurodegeneration caused by PD due to its unclear and complex pathogenic mechanisms. It has been wildly recognized that both gut microbiota and neuro-immunity are involved in the pathology of PD. In this review, we intend to provide a comprehensive overview of current knowledge on how gut microbiota involved in immune-driven pathogenesis of PD, and its potential as a new target of dietary and/or therapeutic interventions for PD.

2.
Biosci Biotechnol Biochem ; 84(1): 134-142, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31490096

RESUMO

Plumbagin (PLB), an alkaloid obtained from the roots of the plants of Plumbago genus, is an inhibitor of NADPH oxidase 4 (NOX4). This study aimed to investigate the beneficial effect of PLB against oxygen-glucose deprivation/reoxygenation (OGDR)-induced neuroinjury in human SH-SY5Y neuronal cultures. Our results showed that OGD/R stimulated NOX4 protein expression and reactive oxygen species (ROS) production in SH-SY5Y cells, whereas increased 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) production, resulting in the activation of the NLRP3 inflammasome. And PLB pretreatment reduced the ROS production by regulating the expression of NOX4 and downregulated NF-κB signaling which was induced by OGDR. Furthermore, PLB inhibited OGDR induced NLRP3 inflammasome activation but not PARP1. Overall, PLB improved OGDR induced neuroinjury by inhibiting NOX4-derived ROS-activated NLRP3 inflammasome.


Assuntos
Hipóxia Celular/efeitos dos fármacos , Glucose/deficiência , Inflamassomos/metabolismo , NADPH Oxidase 4/antagonistas & inibidores , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Naftoquinonas/farmacologia , Neurônios/metabolismo , Extratos Vegetais/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Apoptose/efeitos dos fármacos , Isquemia Encefálica/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , NF-kappa B/antagonistas & inibidores , Estresse Oxidativo/efeitos dos fármacos , Raízes de Plantas/química , Plumbaginaceae/química
3.
Ying Yong Sheng Tai Xue Bao ; 30(12): 4361-4368, 2019 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-31840483

RESUMO

With the intensification of climate change and human activities, megafires frequently occur, with serious impacts on ecosystems, atmospheric environment, and human health. The United States has accumulated a large amount of practical experience in forest fire management. A comprehensive review of the framework of forest fire management in the United States can provide an inspiring reference for forest fire prevention in China. Starting from the process of historical evolution of forest fire policy, we systematically introduced the four stages of policy evolution and the characteristics of each stage in the US. Moreover, a comprehensive analysis of forest fire management situation in the US from four aspects was conducted, including the management of combustible fuels, administrative responsibility, fire suppression and forest fire management research support. We summarized relevant literature and proposed improvement strategies for future combustibles management, policy politics and fire fighting in the United States. Through the comprehensive analysis of forest fire management in the United States, we put forward some inspiring opinions on forest fire management in China to promote the establishment of a sound forest fire management system with Chinese characteristics.


Assuntos
Fogo , Incêndios Florestais , China , Ecossistema , Florestas , Humanos , Árvores , Estados Unidos
4.
Sci Rep ; 9(1): 15678, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31666554

RESUMO

The idea that original soft tissue structures and the native structural proteins comprising them can persist across geological time is controversial, in part because rigorous and testable mechanisms that can occur under natural conditions, resulting in such preservation, have not been well defined. Here, we evaluate two non-enzymatic structural protein crosslinking mechanisms, Fenton chemistry and glycation, for their possible contribution to the preservation of blood vessel structures recovered from the cortical bone of a Tyrannosaurus rex (USNM 555000 [formerly, MOR 555]). We demonstrate the endogeneity of the fossil vessel tissues, as well as the presence of type I collagen in the outermost vessel layers, using imaging, diffraction, spectroscopy, and immunohistochemistry. Then, we use data derived from synchrotron FTIR studies of the T. rex vessels to analyse their crosslink character, with comparison against two non-enzymatic Fenton chemistry- and glycation-treated extant chicken samples. We also provide supporting X-ray microprobe analyses of the chemical state of these fossil tissues to support our conclusion that non-enzymatic crosslinking pathways likely contributed to stabilizing, and thus preserving, these T. rex vessels. Finally, we propose that these stabilizing crosslinks could play a crucial role in the preservation of other microvascular tissues in skeletal elements from the Mesozoic.

5.
Nan Fang Yi Ke Da Xue Xue Bao ; 39(6): 718-723, 2019 Jun 30.
Artigo em Chinês | MEDLINE | ID: mdl-31270052

RESUMO

OBJECTIVE: To establish an improved mouse model of valproic acid (VPA)-induced autism that better mimics human autism. METHODS: We established mouse models of autism in female C57 mice by intraperitoneal injection of sodium valproate either at a single dose (600 mg/kg) on day 12.5 after conception (conventional group) or in two doses of 300 mg/kg each on days 10 and 12 after conception (modified group), and the control mice were injected with saline only on day 12.5. The responses of the mice to VPA injection, the uterus, mortality rate, and abortion rate were compared among the 3 groups. The morphology and development of the offspring mice were assessed, and their behavioral ontogeny was evaluated using 3- chambered social test, social test, juvenil play test, and open field test. RESULTS: The mortality and abortion rates were significantly lower in the modified model group than in the conventional group (P < 0.01). Compared with those in the control group, the offspring mice in both the conventional group and the modified group showed developmental disorders (P < 0.05). The mortality rate of the newborn mice was significantly lower in the modified group than in the conventional group with a rate of curvy tail of up to 100% (P < 0.001). The offspring mice in both the modified group and conventional group exhibited autism-like behavioral abnormalities, including social disorder and repetitive stereotyped behavior (P < 0.05). CONCLUSIONS: The mouse model of autism established using the modified method better mimics human autism with reduced mortality and abortion rates of the pregnant mice and also decreased mortality rate of the newborn mice.


Assuntos
Transtorno Autístico , Animais , Modelos Animais de Doenças , Feminino , Camundongos , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Ácido Valproico
6.
Proteomics ; 19(16): e1800251, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31172628

RESUMO

Molecular studies have contributed greatly to our understanding of evolutionary processes that act upon virtually every aspect of living organisms. However, these studies are limited with regard to extinct organisms, particularly those from the Mesozoic because fossils pose unique challenges to molecular workflows, and because prevailing wisdom suggests no endogenous molecular components can persist into deep time. Here, the power and potential of a molecular approach to Mesozoic fossils is discussed. Molecular methods that have been applied to Mesozoic fossils-including iconic, non-avian dinosaurs- and the challenges inherent in such analyses, are compared and evaluated. Taphonomic processes resulting in the transition of living organisms from the biosphere into the fossil record are reviewed, and the possible effects of taphonomic alteration on downstream analyses that can be problematic for very old material (e.g., molecular modifications, limitations of on comparative databases) are addressed. Molecular studies applied to ancient remains are placed in historical context, and past and current studies are evaluated with respect to producing phylogenetically and/or evolutionarily significant data. Finally, some criteria for assessing the presence of endogenous biomolecules in very ancient fossil remains are suggested as a starting framework for such studies.

7.
Life Sci ; 231: 116563, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31200003

RESUMO

AIMS: In the present study, we investigated the roles of renin-angiotensin system (RAS) activation and imbalance of matrix metalloproteinase-9 (MMP-9)/tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in cold-induced stroke during chronic hypertension, as well as the protective effects of captopril and recombinant human TIMP-1 (rhTIMP-1). MAIN METHODS: Rats were randomly assigned to sham; 2-kidney, 2-clip (2K-2C); 2K-2C + captopril, and 2K-2C + rhTIMP-1 groups. After blood pressure values had stabilized, each group was randomly divided into an acute cold exposure (ACE) group (12-h light at 22 °C/12-h dark at 4 °C) and a non-acute cold exposure (NACE) group (12-h light/12-h dark at 22 °C), each of which underwent three cycles of exposure. Captopril treatment was administered via gavage (50 mg/kg/d), while rhTIMP-1 treatment was administered via the tail vein (60 µg/kg/36 h). KEY FINDINGS: In the 2K-2C group, angiotensin II (AngII) and MMP-9 levels increased in both the plasma and cortex, while no such changes in TIMP-1 expression were observed. Cold exposure further upregulated AngII and MMP-9 levels and increased stroke incidence. Captopril and rhTIMP-1 treatment inhibited MMP-9 expression and activation and decreased stroke incidence in response to cold exposure. SIGNIFICANCE: The present study is the first to demonstrate that cold exposure exacerbates imbalance between MMP-9 and TIMP-1 by activating the RAS, which may be critical in the initiation of stroke during chronic hypertension. In addition, our results suggest that captopril and rhTIMP-1 exert protective effects against cold-induced stroke by ameliorating MMP-9/TIMP-1 imbalance.


Assuntos
Metaloproteinase 9 da Matriz/metabolismo , Sistema Renina-Angiotensina/fisiologia , Acidente Vascular Cerebral/metabolismo , Inibidor Tecidual de Metaloproteinase-1/metabolismo , Angiotensina II/metabolismo , Animais , Pressão Sanguínea/efeitos dos fármacos , Captopril/metabolismo , Captopril/farmacologia , Proteínas de Ciclo Celular/metabolismo , Temperatura Baixa/efeitos adversos , Humanos , Rim/metabolismo , Masculino , Metaloproteinase 1 da Matriz/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/farmacologia , Sistema Renina-Angiotensina/genética , Acidente Vascular Cerebral/fisiopatologia , Inibidor Tecidual de Metaloproteinase-1/farmacologia , Inibidor Tecidual de Metaloproteinase-2
8.
Proc Natl Acad Sci U S A ; 116(8): 3018-3023, 2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30692253

RESUMO

Dinosaur fossils possessing integumentary appendages of various morphologies, interpreted as feathers, have greatly enhanced our understanding of the evolutionary link between birds and dinosaurs, as well as the origins of feathers and avian flight. In extant birds, the unique expression and amino acid composition of proteins in mature feathers have been shown to determine their biomechanical properties, such as hardness, resilience, and plasticity. Here, we provide molecular and ultrastructural evidence that the pennaceous feathers of the Jurassic nonavian dinosaur Anchiornis were composed of both feather ß-keratins and α-keratins. This is significant, because mature feathers in extant birds are dominated by ß-keratins, particularly in the barbs and barbules forming the vane. We confirm here that feathers were modified at both molecular and morphological levels to obtain the biomechanical properties for flight during the dinosaur-bird transition, and we show that the patterns and timing of adaptive change at the molecular level can be directly addressed in exceptionally preserved fossils in deep time.


Assuntos
Evolução Molecular , Plumas/química , Queratinas/química , beta-Queratinas/química , Animais , Aves , Dinossauros , Plumas/ultraestrutura , Fósseis , Pele/química , Pele/ultraestrutura
9.
J Neurovirol ; 25(1): 127-132, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30397825

RESUMO

Vibrio vulnificus usually causes wound infection, gastroenteritis, and septicemia. However, it is a rare conditional pathogen causing meningoencephalitis. We report a case of a young, immunocompromised man presenting with severe sepsis after exposure to sea water and consumption of seafood. The patient subsequently developed meningoencephalitis, and Vibrio vulnificus was isolated from his blood culture. The sequence was confirmed by Next-generation sequencing of a sample of cerebrospinal fluid, as well as from a bacteria culture. After the pathogen was detected, the patient was treated with ceftriaxone, doxycycline, and moxifloxacin for 6 weeks, which controlled his infection. In this case, we acquired his clinical and dynamic MRI presentations, which were never reported. Physicians should consider Vibrio vulnificus infections when they see a similar clinical course, brain CT and MRI findings, susceptibility factors and recent seafood ingestion or exposure to seawater. Due to high mortality, the early diagnosis and treatment of Vibrio vulnificus infections are crucial. Next-generation sequencing was found to be useful for diagnosis.

10.
Nature ; 564(7736): 359-365, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30518862

RESUMO

Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses recovered still-flexible remnants of the original scaleless skin, which comprises morphologically distinct epidermal and dermal layers. These are underlain by insulating blubber that would have augmented streamlining, buoyancy and homeothermy. Additionally, we identify endogenous proteinaceous and lipid constituents, together with keratinocytes and branched melanophores that contain eumelanin pigment. Distributional variation of melanophores across the body suggests countershading, possibly enhanced by physiological adjustments of colour to enable photoprotection, concealment and/or thermoregulation. Convergence of ichthyosaurs with extant marine amniotes thus extends to the ultrastructural and molecular levels, reflecting the omnipresent constraints of their shared adaptation to pelagic life.


Assuntos
Evolução Biológica , Regulação da Temperatura Corporal , Dinossauros/anatomia & histologia , Dinossauros/fisiologia , Fósseis , Homeostase , Adaptação Fisiológica , Tecido Adiposo/anatomia & histologia , Tecido Adiposo/química , Animais , Derme/anatomia & histologia , Derme/química , Golfinhos , Epiderme/anatomia & histologia , Epiderme/química , Feminino , Queratinócitos/química , Lipídeos/análise , Masculino , Melaninas/análise , Melanóforos/química , Toninhas , Proteínas/análise
11.
PLoS One ; 13(11): e0206569, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30485294

RESUMO

Multiple fossil discoveries and taphonomic experiments have established the durability of keratin. The utility and specificity of antibodies to identify keratin peptides has also been established, both in extant feathers under varying treatment conditions, and in feathers from extinct organisms. Here, we show localization of feather-keratin antibodies to control and heat-treated feathers, testifying to the repeatability of initial data supporting the preservation potential of keratin. We then show new data at higher resolution that demonstrates the specific response of these antibodies to the feather matrix, we support the presence of protein in heat-treated feathers using ToF-SIMS, and we apply these methods to a fossil feather preserved in the unusual environment of sinter hot springs. We stress the importance of employing realistic conditions such as sediment burial when designing experiments intended as proxies for taphonomic processes occurring in the fossil record. Our data support the hypothesis that keratin, particularly the ß-keratin that comprises feathers, has potential to preserve in fossil remains.


Assuntos
Plumas , Fósseis , Queratinas , Animais , Anticorpos , Plumas/química , Plumas/imunologia , Plumas/ultraestrutura , Fósseis/ultraestrutura , Fontes Termais , Temperatura Alta , Queratinas/química , Queratinas/imunologia , Tetra-Hidroisoquinolinas , Fatores de Tempo
12.
BMC Neurol ; 18(1): 174, 2018 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-30342480

RESUMO

BACKGROUND: DNA methyltransferase 1 (EC 2.1.1.37), encoded by DNMT1 gene, is one of key enzymes in maintaining DNA methylation patterns of the human genome. It plays a crucial role in embryonic development, imprinting and genome stability, cell differentiation. The dysfunction of this group of enzymes can lead to a variety of human genetic disorders. Until now, mutations in DNMT1 have been found to be associated with two distinct phenotypes. Mutations in exon 20 of this gene leads to hereditary sensory and autonomic neuropathy type IE, and mutations in exon 21 cause autosomal dominant cerebellar ataxia, deafness and narcolepsy. CASE PRESENTATION: Here we report a novel DNMT1 mutation in a sporadic case of a Chinese patient with cerebellar ataxia, multiple motor and sensory neuropathy, hearing loss and psychiatric manifestations. Furthermore, we elucidated its pathogenic effect through molecular genetics studies and revealed that this defective DNMT1 function is responsible for the phenotypes in this individual. CONCLUSION: Our findings expand the spectrum of DNMT1-related disorders and provide a good example of precision medicine through the combination of exome sequencing and clinical testing.


Assuntos
DNA (Citosina-5-)-Metiltransferase 1/genética , Neuropatias Hereditárias Sensoriais e Autônomas/genética , Adulto , Ataxia Cerebelar/genética , Metilação de DNA , Éxons , Feminino , Humanos , Mutação , Fenótipo
13.
Parkinsonism Relat Disord ; 53: 82-88, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29776865

RESUMO

INTRODUCTION: Accumulating evidence has revealed alterations in the communication between the gut and brain in patients with Parkinson's disease (PD), and previous studies have confirmed that alterations in the gut microbiome play an important role in the pathogenesis of numerous diseases, including PD. The aim of this study was to determine whether the faecal microbiome of PD patients in southern China differs from that of control subjects and whether the gut microbiome composition alters among different PD motor phenotypes. METHODS: We compared the gut microbiota composition of 75 patients with PD and 45 age-matched controls using 16S rRNA next-generation-sequencing. RESULTS: We observed significant increases in the abundance of four bacterial families and significant decreases in the abundance of seventeen bacterial families in patients with PD compared to those of the controls. In particular, the abundance of Lachnospiraceae was reduced by 42.9% in patients with PD, whereas Bifidobacteriaceae was enriched in patients with PD. We did not identify a significant difference in the overall microbial composition among different PD motor phenotypes, but we identified the association between specific taxas and different PD motor phenotypes. CONCLUSIONS: PD is accompanied by alterations in the abundance of specific gut microbes. The abundance of certain gut microbes was altered depending on clinical motor phenotypes. Based on our findings, the gut microbiome may be a potential PD biomarker.


Assuntos
Microbioma Gastrointestinal , Doença de Parkinson/microbiologia , Doença de Parkinson/fisiopatologia , Idoso , China , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo , RNA Ribossômico 16S , Análise de Sequência de RNA
14.
Sci Rep ; 7(1): 13324, 2017 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-29042651

RESUMO

The holotype (MHM-K2) of the Eocene cheloniine Tasbacka danica is arguably one of the best preserved juvenile fossil sea turtles on record. Notwithstanding compactional flattening, the specimen is virtually intact, comprising a fully articulated skeleton exposed in dorsal view. MHM-K2 also preserves, with great fidelity, soft tissue traces visible as a sharply delineated carbon film around the bones and marginal scutes along the edge of the carapace. Here we show that the extraordinary preservation of the type of T. danica goes beyond gross morphology to include ultrastructural details and labile molecular components of the once-living animal. Haemoglobin-derived compounds, eumelanic pigments and proteinaceous materials retaining the immunological characteristics of sauropsid-specific ß-keratin and tropomyosin were detected in tissues containing remnant melanosomes and decayed keratin plates. The preserved organics represent condensed remains of the cornified epidermis and, likely also, deeper anatomical features, and provide direct chemical evidence that adaptive melanism - a biological means used by extant sea turtle hatchlings to elevate metabolic and growth rates - had evolved 54 million years ago.


Assuntos
Fósseis , Tartarugas/anatomia & histologia , Animais , Fósseis/anatomia & histologia , Fósseis/ultraestrutura , Imuno-Histoquímica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
15.
J Proteome Res ; 16(2): 920-932, 2017 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-28111950

RESUMO

Sequence data from biomolecules such as DNA and proteins, which provide critical information for evolutionary studies, have been assumed to be forever outside the reach of dinosaur paleontology. Proteins, which are predicted to have greater longevity than DNA, have been recovered from two nonavian dinosaurs, but these results remain controversial. For proteomic data derived from extinct Mesozoic organisms to reach their greatest potential for investigating questions of phylogeny and paleobiology, it must be shown that peptide sequences can be reliably and reproducibly obtained from fossils and that fragmentary sequences for ancient proteins can be increasingly expanded. To test the hypothesis that peptides can be repeatedly detected and validated from fossil tissues many millions of years old, we applied updated extraction methodology, high-resolution mass spectrometry, and bioinformatics analyses on a Brachylophosaurus canadensis specimen (MOR 2598) from which collagen I peptides were recovered in 2009. We recovered eight peptide sequences of collagen I: two identical to peptides recovered in 2009 and six new peptides. Phylogenetic analyses place the recovered sequences within basal archosauria. When only the new sequences are considered, B. canadensis is grouped more closely to crocodylians, but when all sequences (current and those reported in 2009) are analyzed, B. canadensis is placed more closely to basal birds. The data robustly support the hypothesis of an endogenous origin for these peptides, confirm the idea that peptides can survive in specimens tens of millions of years old, and bolster the validity of the 2009 study. Furthermore, the new data expand the coverage of B. canadensis collagen I (a 33.6% increase in collagen I alpha 1 and 116.7% in alpha 2). Finally, this study demonstrates the importance of reexamining previously studied specimens with updated methods and instrumentation, as we obtained roughly the same amount of sequence data as the previous study with substantially less sample material. Data are available via ProteomeXchange with identifier PXD005087.


Assuntos
Colágeno Tipo I/química , Dinossauros/classificação , Fósseis , Fragmentos de Peptídeos/análise , Filogenia , Proteômica/métodos , Sequência de Aminoácidos , Animais , Evolução Biológica , Osso e Ossos/química , Extinção Biológica , Paleontologia/instrumentação , Paleontologia/métodos , Proteômica/instrumentação
16.
Proc Natl Acad Sci U S A ; 113(49): E7900-E7907, 2016 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-27872291

RESUMO

Microbodies associated with feathers of both nonavian dinosaurs and early birds were first identified as bacteria but have been reinterpreted as melanosomes. Whereas melanosomes in modern feathers are always surrounded by and embedded in keratin, melanosomes embedded in keratin in fossils has not been demonstrated. Here we provide multiple independent molecular analyses of both microbodies and the associated matrix recovered from feathers of a new specimen of the basal bird Eoconfuciusornis from the Early Cretaceous Jehol Biota of China. Our work represents the oldest ultrastructural and immunological recognition of avian beta-keratin from an Early Cretaceous (∼130-Ma) bird. We apply immunogold to identify protein epitopes at high resolution, by localizing antibody-antigen complexes to specific fossil ultrastructures. Retention of original keratinous proteins in the matrix surrounding electron-opaque microbodies supports their assignment as melanosomes and adds to the criteria employable to distinguish melanosomes from microbial bodies. Our work sheds new light on molecular preservation within normally labile tissues preserved in fossils.


Assuntos
Aves/anatomia & histologia , Plumas/ultraestrutura , Fósseis/ultraestrutura , Queratinas , Melanossomas , Animais , Evolução Biológica
17.
PLoS One ; 11(7): e0157699, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27384819

RESUMO

Keratinous 'soft tissue' structures (i.e. epidermally derived and originally non-biomineralized), include feathers, skin, claws, beaks, and hair. Despite their relatively common occurrence in the fossil record (second only to bone and teeth), few studies have addressed natural degradation processes that must occur in all organic material, including those keratinous structures that are incorporated into the rock record as fossils. Because feathers have high preservation potential and strong phylogenetic signal, in the current study we examine feathers subjected to different burial environments for a duration of ~10 years, using transmission electron microscopy (TEM) and in situ immunofluorescence (IF). We use morphology and persistence of specific immunoreactivity as indicators of preservation at the molecular and microstructural levels. We show that feather keratin is durable, demonstrates structural and microstructural integrity, and retains epitopes suitable for specific antibody recognition in even the harshest conditions. These data support the hypothesis that keratin antibody reactivity can be used to identify the nature and composition of epidermal structures in the rock record, and to address evolutionary questions by distinguishing between alpha- (widely distributed) and beta- (limited to sauropsids) keratin.


Assuntos
Plumas/química , Fósseis , Queratinas/química , Animais , Anticorpos/química , Evolução Biológica , Galinhas , Epiderme/anatomia & histologia , Humanos , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Unhas , Filogenia , Temperatura Ambiente
18.
PLoS One ; 11(2): e0150238, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26926069

RESUMO

Recovery of still-soft tissue structures, including blood vessels and osteocytes, from dinosaur bone after demineralization was reported in 2005 and in subsequent publications. Despite multiple lines of evidence supporting an endogenous source, it was proposed that these structures arose from contamination from biofilm-forming organisms. To test the hypothesis that soft tissue structures result from microbial invasion of the fossil bone, we used two different biofilm-forming microorganisms to inoculate modern bone fragments from which organic components had been removed. We show fundamental morphological, chemical and textural differences between the resultant biofilm structures and those derived from dinosaur bone. The data do not support the hypothesis that biofilm-forming microorganisms are the source of these structures.


Assuntos
Biofilmes , Osso e Ossos/citologia , Osso e Ossos/microbiologia , Dinossauros , Animais , Bacillus cereus/fisiologia , Vasos Sanguíneos/microbiologia , Osso e Ossos/fisiologia , Calcificação Fisiológica , Bovinos , Fósseis , Staphylococcus epidermidis/fisiologia
19.
Sci Rep ; 6: 23099, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26975806

RESUMO

Medullary bone (MB), an estrogen-dependent reproductive tissue present in extant gravid birds, is texturally, histologically and compositionally distinct from other bone types. Phylogenetic proximity led to the proposal that MB would be present in non-avian dinosaurs, and recent studies have used microscopic, morphological, and regional homologies to identify this reproductive tissue in both theropod and ornithischian dinosaurs. Here, we capitalize on the unique chemical and histological fingerprint of MB in birds to characterize, at the molecular level, MB in the non-avian theropod Tyrannosaurus rex (MOR 1125), and show that the retention of original molecular components in fossils allows deeper physiological and evolutionary questions to be addressed.


Assuntos
Osso e Ossos/anatomia & histologia , Osso e Ossos/química , Dinossauros/anatomia & histologia , Sulfato de Ceratano/análise , Animais , Galinhas/anatomia & histologia , Feminino , Fósseis , Reprodução , Caracteres Sexuais , Análise para Determinação do Sexo , Struthioniformes/anatomia & histologia
20.
Proc Biol Sci ; 283(1842)2016 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-28120795

RESUMO

One of the most well-recognized Cretaceous fossils is Citipati osmolskae (MPC-D 100/979), an oviraptorid dinosaur discovered in brooding position on a nest of unhatched eggs. The original description refers to a thin lens of white material extending from a manus ungual, which was proposed to represent original keratinous claw sheath that, in life, would have covered it. Here, we test the hypothesis that this exceptional morphological preservation extends to the molecular level. The fossil sheath was compared with that of extant birds, revealing similar morphology and microstructural organization. In living birds, the claw sheath consists primarily of two structural proteins; alpha-keratin, expressed in all vertebrates, and beta-keratin, found only in reptiles and birds (sauropsids). We employed antibodies raised against avian feathers, which comprise almost entirely of beta-keratin, to demonstrate that fossil tissues respond with the same specificity, though less intensity, as those from living birds. Furthermore, we show that calcium chelation greatly increased antibody reactivity, suggesting a role for calcium in the preservation of this fossil material.


Assuntos
Evolução Biológica , Dinossauros/anatomia & histologia , Casco e Garras/anatomia & histologia , Animais , Aves/anatomia & histologia , Plumas , Fósseis , Queratinas/química
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