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1.
Eur Spine J ; 33(2): 590-598, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38224408

RESUMO

PURPOSE: Three-column osteotomies (TCOs) and minimally invasive techniques such as anterior column realignment (ACR) are powerful tools used to restore lumbar lordosis and sagittal alignment. We aimed to appraise the differences in construct and global spinal stability between TCOs and ACRs in long constructs. METHODS: We identified consecutive patients who underwent a long construct lumbar or thoracolumbar fusion between January 2016 and November 2021. "Long construct" was any construct where the uppermost instrumented vertebra (UIV) was L2 or higher and the lowermost instrumented vertebra (LIV) was in the sacrum or ileum. RESULTS: We identified 69 patients; 14 (20.3%) developed PJK throughout follow-up (mean 838 days). Female patients were less likely to suffer PJK (p = 0.009). TCO was more associated with open (versus minimally invasive) screw/rod placement, greater number of levels, higher UIV, greater rate of instrumentation to the ilium, and posterior (versus anterior) L5-S1 interbody placement versus the ACR cohort (p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.005, respectively). Patients who developed PJK were more likely to have undergone ACR (12 (32.4%) versus 2 (6.3%, p = 0.007)). The TCO cohort had better improvement of lumbar lordosis despite similar preoperative measurements (ACR: 16.8 ± 3.78°, TCO: 23.0 ± 5.02°, p = 0.046). Pelvic incidence-lumbar lordosis mismatch had greater improvement after TCO (ACR: 14.8 ± 4.02°, TCO: 21.5 ± 5.10°, p = 0.042). By multivariate analysis, ACR increased odds of PJK by 6.1-times (95% confidence interval: 1.20-31.2, p = 0.29). CONCLUSION: In patients with long constructs who undergo ACR or TCO, we experienced a 20% rate of PJK. TCO decreased PJK 6.1-times compared to ACR. TCO demonstrated greater improvement of some spinopelvic parameters.


Assuntos
Cifose , Lordose , Anormalidades Musculoesqueléticas , Animais , Humanos , Feminino , Lordose/diagnóstico por imagem , Lordose/cirurgia , Sacro , Parafusos Ósseos , Osteotomia
2.
Mol Phylogenet Evol ; 163: 107210, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34029720

RESUMO

One of the most urgent contemporary tasks for taxonomists and evolutionary biologists is to estimate the number of species on earth. Recording alpha diversity is crucial for protecting biodiversity, especially in areas of elevated species richness, which coincide geographically with increased anthropogenic environmental pressures - the world's so-called biodiversity hotspots. Although the distribution of Puddle frogs of the genus Occidozyga in South and Southeast Asia includes five biodiversity hotspots, the available data on phylogeny, species diversity, and biogeography are surprisingly patchy. Samples analyzed in this study were collected throughout Southeast Asia, with a primary focus on Sundaland and the Philippines. A mitochondrial gene region comprising ~ 2000 bp of 12S and 16S rRNA with intervening tRNA Valine and three nuclear loci (BDNF, NTF3, POMC) were analyzed to obtain a robust, time-calibrated phylogenetic hypothesis. We found a surprisingly high level of genetic diversity within Occidozyga, based on uncorrected p-distance values corroborated by species delimitation analyses. This extensive genetic diversity revealed 29 evolutionary lineages, defined by the > 5% uncorrected p-distance criterion for the 16S rRNA gene, suggesting that species diversity in this clade of phenotypically homogeneous forms probably has been underestimated. The comparison with results of other anuran groups leads to the assumption that anuran species diversity could still be substantially underestimated in Southeast Asia in general. Many genetically divergent lineages of frogs are phenotypically similar, indicating a tendency towards extensive morphological conservatism. We present a biogeographic reconstruction of the colonization of Sundaland and nearby islands which, together with our temporal framework, suggests that lineage diversification centered on the landmasses of the northern Sunda Shelf. This remarkably genetically structured group of amphibians could represent an exceptional case for future studies of geographical structure and diversification in a widespread anuran clade spanning some of the most pronounced geographical barriers on the planet (e.g., Wallace's Line). Studies considering gene flow, morphology, ecological and bioacoustic data are needed to answer these questions and to test whether observed diversity of Puddle frog lineages warrants taxonomic recognition.


Assuntos
Anuros , Biodiversidade , Animais , Anuros/genética , Teorema de Bayes , Filogenia , Filogeografia , RNA Ribossômico 16S/genética , Especificidade da Espécie
3.
J Anat ; 235(2): 357-378, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31062345

RESUMO

Computed-tomography-derived (CT-derived) polymesh surfaces are widely used in geometric morphometric studies. This approach is inevitably associated with decisions on scanning parameters, resolution, and segmentation strategies. Although the underlying processing steps have been shown to potentially contribute artefactual variance to three-dimensional landmark coordinates, their effects on measurement error have rarely been assessed systematically in CT-based geometric morphometric studies. The present study systematically assessed artefactual variance in landmark data introduced by the use of different voxel sizes, segmentation strategies, surface simplification degrees, and by inter- and intra-observer differences, and compared their magnitude to true biological variation. Multiple CT-derived surface variants of the anuran (Amphibia: Anura) pectoral girdle were generated by systematic changes in the factors that potentially influence the surface geometries. Twenty-four landmarks were repeatedly acquired by different observers. The contribution of all factors to the total variance in the landmark data was assessed using random-factor nested permanovas. Selected sets of Euclidean distances between landmark sets served further to compare the variance among factor levels. Landmark precision was assessed by landmark standard deviation and compared among observers and days. Results showed that all factors, except for voxel size, significantly contributed to measurement error in at least some of the analyses performed. In total, 6.75% of the variance in landmark data that mimicked a realistic biological study was caused by measurement error. In this landmark dataset, intra-observer error was the major source of artefactual variance followed by inter-observer error; the factor segmentation contributed < 1% and slight surface simplification had no significant effect. Inter-observer error clearly exceeded intra-observer error in a different landmark dataset acquired by six partly inexperienced observers. The results suggest that intra-observer error can potentially be reduced by including a training period prior to the actual landmark acquisition task and by acquiring landmarks in as few sessions as possible. Additionally, the application of moderate and careful surface simplification and, potentially, also the use of case-specific optimal combinations of automatic local thresholding algorithms and parameters for segmentation can help reduce intra-observer error. If landmark data are to be acquired by several observers, it is important to ensure that all observers are consistent in landmark identification. Despite the significant amount of artefactual variance, we have shown that landmark data acquired from microCT-derived surfaces are precise enough to study the shape of anuran pectoral girdles. Yet, a systematic assessment of measurement error is advisable for all geometric morphometric studies.


Assuntos
Pontos de Referência Anatômicos/diagnóstico por imagem , Anuros/anatomia & histologia , Imageamento Tridimensional , Microtomografia por Raio-X , Animais , Esqueleto/diagnóstico por imagem
4.
Proc Natl Acad Sci U S A ; 112(34): 10732-7, 2015 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-26261303

RESUMO

The diphthamide on human eukaryotic translation elongation factor 2 (eEF2) is the target of ADP ribosylating diphtheria toxin (DT) and Pseudomonas exotoxin A (PE). This modification is synthesized by seven dipthamide biosynthesis proteins (DPH1-DPH7) and is conserved among eukaryotes and archaea. We generated MCF7 breast cancer cell line-derived DPH gene knockout (ko) cells to assess the impact of complete or partial inactivation on diphthamide synthesis and toxin sensitivity, and to address the biological consequence of diphthamide deficiency. Cells with heterozygous gene inactivation still contained predominantly diphthamide-modified eEF2 and were as sensitive to PE and DT as parent cells. Thus, DPH gene copy number reduction does not affect overall diphthamide synthesis and toxin sensitivity. Complete inactivation of DPH1, DPH2, DPH4, and DPH5 generated viable cells without diphthamide. DPH1ko, DPH2ko, and DPH4ko harbored unmodified eEF2 and DPH5ko ACP- (diphthine-precursor) modified eEF2. Loss of diphthamide prevented ADP ribosylation of eEF2, rendered cells resistant to PE and DT, but does not affect sensitivity toward other protein synthesis inhibitors, such as saporin or cycloheximide. Surprisingly, cells without diphthamide (independent of which the DPH gene compromised) were presensitized toward nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) and death-receptor pathways without crossing lethal thresholds. In consequence, loss of diphthamide rendered cells hypersensitive toward TNF-mediated apoptosis. This finding suggests a role of diphthamide in modulating NF-κB, death receptor, or apoptosis pathways.


Assuntos
Apoptose/fisiologia , Histidina/análogos & derivados , NF-kappa B/fisiologia , Fator 2 de Elongação de Peptídeos/química , Receptores de Morte Celular/fisiologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas de Bactérias/farmacologia , Neoplasias da Mama/patologia , Carbono-Nitrogênio Ligases/deficiência , Carbono-Nitrogênio Ligases/fisiologia , Linhagem Celular Tumoral , Toxina Diftérica/farmacologia , Feminino , Dosagem de Genes , Técnicas de Inativação de Genes , Histidina/biossíntese , Histidina/deficiência , Humanos , Proteínas de Neoplasias/fisiologia , Processamento de Proteína Pós-Traducional
5.
J Biol Chem ; 291(7): 3395-410, 2016 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-26677222

RESUMO

By non-covalent association after proteolytic cleavage, the pro-domains modulate the activities of the mature growth factor domains across the transforming growth factor-ß family. In the case of bone morphogenic protein 9 (BMP9), however, the pro-domains do not inhibit the bioactivity of the growth factor, and the BMP9·pro-domain complexes have equivalent biological activities as the BMP9 mature ligand dimers. By using real-time surface plasmon resonance, we could demonstrate that either binding of pro-domain-complexed BMP9 to type I receptor activin receptor-like kinase 1 (ALK1), type II receptors, co-receptor endoglin, or to mature BMP9 domain targeting antibodies leads to immediate and complete displacement of the pro-domains from the complex. Vice versa, pro-domain binding by an anti-pro-domain antibody results in release of the mature BMP9 growth factor. Based on these findings, we adjusted ELISA assays to measure the protein levels of different BMP9 variants. Although mature BMP9 and inactive precursor BMP9 protein were directly detectable by ELISA, BMP9·pro-domain complex could only be measured indirectly as dissociated fragments due to displacement of mature growth factor and pro-domains after antibody binding. Our studies provide a model in which BMP9 can be readily activated upon getting into contact with its receptors. This increases the understanding of the underlying biology of BMP9 activation and also provides guidance for ELISA development for the detection of circulating BMP9 variants.


Assuntos
Receptores de Activinas Tipo II/metabolismo , Antígenos CD/metabolismo , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/metabolismo , Fatores de Diferenciação de Crescimento/metabolismo , Modelos Moleculares , Receptores de Superfície Celular/metabolismo , Receptores de Activinas Tipo II/química , Receptores de Activinas Tipo II/genética , Animais , Antígenos CD/química , Antígenos CD/genética , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/química , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/genética , Células Cultivadas , Dimerização , Endoglina , Feminino , Fator 2 de Diferenciação de Crescimento/sangue , Fator 2 de Diferenciação de Crescimento/isolamento & purificação , Fator 2 de Diferenciação de Crescimento/metabolismo , Fatores de Diferenciação de Crescimento/sangue , Fatores de Diferenciação de Crescimento/química , Fatores de Diferenciação de Crescimento/genética , Células HEK293 , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Camundongos Endogâmicos BALB C , Fragmentos de Peptídeos/agonistas , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/isolamento & purificação , Fragmentos de Peptídeos/metabolismo , Domínios e Motivos de Interação entre Proteínas , Precursores de Proteínas/sangue , Precursores de Proteínas/química , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Receptores de Superfície Celular/química , Receptores de Superfície Celular/genética , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Organismos Livres de Patógenos Específicos
6.
Proc Natl Acad Sci U S A ; 108(21): 8731-6, 2011 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-21555583

RESUMO

Anurans (frogs and toads) are unique among land vertebrates in possessing a free-living larval stage that, parallel to adult frogs, diversified into an impressive range of ecomorphs. The tempo and mode at which tadpole morphology evolved through anuran history as well as its relationship to lineage diversification remain elusive. We used a molecular phylogenetic framework to examine patterns of morphological evolution in tadpoles in light of observed episodes of accelerated lineage diversification. Our reconstructions show that the expansion of tadpole morphospace during the basal anuran radiation in the Triassic/Early Jurassic was unparalleled by the basal neobatrachian radiation in the Late Jurassic/Early Cretaceous or any subsequent radiation in the Late Cretaceous/Early Tertiary. Comparative analyses of radiation episodes indicate that the slowdown of morphospace expansion was caused not only by a drop in evolutionary rate after the basal anuran radiation but also by an overall increase in homoplasy in the characters that did evolve during later radiations. The overlapping sets of evolving characters among more recent radiations may have enhanced tadpole diversity by creating unique combinations of homoplastic traits, but the lack of innovative character changes prevented the exploration of fundamental regions in morphospace. These complex patterns transcend the four traditionally recognized tadpole morphotypes and apply to most tissue types and body parts.


Assuntos
Anuros/anatomia & histologia , Evolução Biológica , Larva/anatomia & histologia , Animais , Anuros/genética , Larva/genética , Filogenia
7.
Proc Natl Acad Sci U S A ; 108(20): 8194-9, 2011 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-21536919

RESUMO

Bispecific antibodies that bind cell-surface targets as well as digoxigenin (Dig) were generated for targeted payload delivery. Targeting moieties are IgGs that bind the tumor antigens Her2, IGF1R, CD22, or LeY. A Dig-binding single-chain Fv was attached in disulfide-stabilized form to C termini of CH3 domains of targeting antibodies. Bispecific molecules were expressed in mammalian cells and purified in the same manner as unmodified IgGs. They are stable without aggregation propensity and retain binding specificity/affinity to cell-surface antigens and Dig. Digoxigeninylated payloads were generated that retain full functionality and can be complexed to bispecific antibodies in a defined 21 ratio. Payloads include small compounds (Dig-Cy5, Dig-Doxorubicin) and proteins (Dig-GFP). Complexed payloads are targeted by the bispecifics to cancer cells and because these complexes are stable in serum, they can be applied for targeted delivery. Because Dig bispecifics also effectively capture digoxigeninylated compounds under physiological conditions, separate administration of uncharged Dig bispecifics followed by application of Dig payload is sufficient to achieve antibody-mediated targeting in vitro and in vivo.


Assuntos
Anticorpos Biespecíficos/uso terapêutico , Antineoplásicos/administração & dosagem , Digoxigenina/imunologia , Sistemas de Liberação de Medicamentos/métodos , Anticorpos Biespecíficos/imunologia , Antígenos de Neoplasias/imunologia , Carbocianinas/administração & dosagem , Linhagem Celular Tumoral , Doxorrubicina/administração & dosagem , Proteínas de Fluorescência Verde/administração & dosagem , Humanos , Métodos , Anticorpos de Cadeia Única
8.
Zootaxa ; (3814): 419-31, 2014 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-24943439

RESUMO

A new species of stream toad of the genus Ansonia is described from Gunung Murud, Pulong Tau National Park, of northern Sarawak, Malaysia, Borneo. Ansonia vidua, sp. nov., is morphologically distinguished from its Bornean congeners by the following combination of characters: medium size (SVL of adult females 33.5-34.4 mm); body uniformly black-brown in life; absence of a visible pattern on dorsum or limbs; presence of two low interorbital ridges; shagreened skin on dorsum, sides and upper surfaces of the limbs with numerous homogeneously small, rounded warts; first finger shorter than second; reduced webbing between the toes and an absence of a sharp tarsal ridge. Uncorrected genetic distances between related taxa of > 4.3% in 16S rRNA gene support its status as a hitherto undescribed species.


Assuntos
Bufonidae/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Animais , Bufonidae/anatomia & histologia , Bufonidae/genética , Ecossistema , Feminino , Malásia , Masculino , Dados de Sequência Molecular , Filogenia
9.
Zootaxa ; 3785: 550-60, 2014 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-24872245

RESUMO

A new brightly-coloured (olive and red) species of microhylid frog of the genus Calluella Stoliczka 1872 is described from the upper elevations of Gunung Penrissen and the Matang Range, Sarawak, East Malaysia (Borneo). Calluella capsa, new species, is diagnosable in showing the following combination of characters: SVL up to 36.0 mm; dorsum weakly granular; a faint dermal fold across forehead; toe tips obtuse; webbing on toes basal; lateral fringes on toes present; outer metatarsal tubercle present; and dorsum greyish-olive, with red spots; half of venter bright red, the rest with large white and dark areas. The new species is the eighth species of Calluella to be described, and the fourth known from Borneo. A preliminary phylogeny of Calluella and its relatives is presented, and the new taxon compared with congeners from Malaysia and other parts of south-east Asia. 


Assuntos
Anuros/anatomia & histologia , Anuros/classificação , Animais , Anuros/genética , Demografia , Malásia , Masculino , Filogenia , Especificidade da Espécie
10.
Mol Phylogenet Evol ; 68(3): 567-81, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23578599

RESUMO

The tree-frog family Rhacophoridae is a major group contributing to the high pecies richness and reproductive diversity among vertebrates of Sundaland. Nonetheless, rhacophorid evolution, specially on Borneo, has not been studied within a phylogenetic context. In this study, we examine the phylogenetic relationships of 38 (out of 41) Bornean species of Rhacophoridae, in combination with data from previous phylogenetic studies. In the final super matrix of 91 species, we analyse sequence data from two mitochondrial and three nuclear genes. The resulting trees show the genus Rhacophorus as a paraphyletic assemblage. As a consequence, we transfer Rhacophorus appendiculatus and R. kajau to two other genera and propose the new phylogeny-based combinations--Kurixalus appendiculatus and Feihyla kajau, respectively. Furthermore, we use our phylogenetic hypotheses to reconstruct the evolution of reproductive modes in rhacophorid tree frogs. Direct development to the exclusion of a free larval stage evolved twice independently, once in an ancestor of the Pseudophilautus+Raorchestes clade in India and Sri Lanka, and once within Philautus in Southeast Asia. The deposition of egg clutches covered by a layer of jelly in Feihyla is also present in F. kajau and thus confirms our generic reassignment. The remarkably high diversity of rhacophorid tree frogs on Borneo is the outcome of a complex pattern of repeated vicariance and dispersal events caused by past changes in the climatic and geological history of the Sunda shelf. We identified geographic clades of closely related endemic species within Rhacophorus and Philautus, which result from local island radiations on Borneo.


Assuntos
Anuros/classificação , Anuros/genética , Biodiversidade , Evolução Biológica , Animais , Sudeste Asiático , DNA Mitocondrial/genética , Evolução Molecular , Filogenia
11.
Biochem J ; 442(3): 583-93, 2012 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-22150630

RESUMO

Access of therapeutic biomolecules to cytoplasmic and nuclear targets is hampered by the inability of these molecules to cross biological membranes. Approaches to overcome this hurdle involve CPPs (cell-penetrating peptides) or protein transduction domains. Most of these require rather high concentrations to elicit cell-penetrating functionality, are non-human, pathogen-derived or synthetic entities, and may therefore not be tolerated or even immunogenic. We identified novel human-protein-derived CPPs by a combination of in silico and experimental analyses: polycationic CPP candidates were identified in an in silico library of all 30-mer peptides of the human proteome. Of these peptides, 60 derived from extracellular proteins were evaluated experimentally. Cell viability and siRNA (small interfering RNA) transfection assays revealed that 20 out of the 60 peptides were functional. Three of these showed CPP functionality without interfering with cell viability. A peptide derived from human NRTN (neurturin), which contains an α-helix, performed the best in our screen and was uniformly taken up by cultured cells. Examples for payloads that can be delivered to the cytosol by the NRTN peptide include complexed siRNAs and both N- and C-terminally fused pro-apoptotic peptides.


Assuntos
Peptídeos Penetradores de Células/química , Sistemas de Liberação de Medicamentos/métodos , Sequência de Aminoácidos , Sobrevivência Celular , Peptídeos Penetradores de Células/administração & dosagem , Células Cultivadas , Citosol/metabolismo , Humanos , RNA Interferente Pequeno , Transfecção
12.
Biophys J ; 103(6): 1305-14, 2012 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-22995503

RESUMO

The E-pathway of transmembrane proton transfer has been demonstrated previously to be essential for catalysis by the diheme-containing quinol:fumarate reductase (QFR) of Wolinella succinogenes. Two constituents of this pathway, Glu-C180 and heme b(D) ring C (b(D)-C-) propionate, have been validated experimentally. Here, we identify further constituents of the E-pathway by analysis of molecular dynamics simulations. The redox state of heme groups has a crucial effect on the connectivity patterns of mobile internal water molecules that can transiently support proton transfer from the b(D)-C-propionate to Glu-C180. The short H-bonding paths formed in the reduced states can lead to high proton conduction rates and thus provide a plausible explanation for the required opening of the E-pathway in reduced QFR. We found evidence that the b(D)-C-propionate group is the previously postulated branching point connecting proton transfer to the E-pathway from the quinol-oxidation site via interactions with the heme b(D) ligand His-C44. An essential functional role of His-C44 is supported experimentally by site-directed mutagenesis resulting in its replacement with Glu. Although the H44E variant enzyme retains both heme groups, it is unable to catalyze quinol oxidation. All results obtained are relevant to the QFR enzymes from the human pathogens Campylobacter jejuni and Helicobacter pylori.


Assuntos
Simulação de Dinâmica Molecular , Oxirredutases/química , Oxirredutases/metabolismo , Membrana Celular/metabolismo , Ácido Glutâmico/metabolismo , Ligação de Hidrogênio , Ligantes , Mutagênese Sítio-Dirigida , Oxirredução , Oxirredutases/genética , Propionatos/metabolismo , Conformação Proteica , Prótons , Água/metabolismo , Wolinella/enzimologia
13.
Glia ; 60(1): 96-111, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21989594

RESUMO

Microglia are increasingly recognized to be crucially involved in the maintenance of tissue homeostasis of the brain and spinal cord. Not surprisingly is therefore the growing scientific interest in the microglia phenotypes associated with various physiological and pathological processes of the central nervous system. Until recently the investigation of these phenotypes was hindered by the lack of an isolation protocol that (without an extended culturing period) would offer a microglia population of high purity and yield. Thus, our objective was to establish a rapid and efficient method for the isolation of human microglia from postmortem brain samples. We tested multiple elements of already existing protocols (e.g., density separation, immunomagnetic bead separation) and combined them to minimize preparation time and maximize yield and purity. The procedure presented in this article enables acute isolation of human microglia from autopsy (and biopsy) samples with a purity and yield that is suitable for downstream applications, such as protein and gene expression analysis and functional assays. Moreover, the present protocol is appropriate for the isolation of microglia from autopsy samples irrespective of the neurological state of the brain or specific brain regions and (with minor modification) could be even used for the isolation of microglia from human glioma tissue.


Assuntos
Astrócitos/fisiologia , Encéfalo/citologia , Citometria de Fluxo/métodos , Separação Imunomagnética/métodos , Adolescente , Adulto , Idoso , Anexina A5/metabolismo , Astrócitos/classificação , Autopsia/métodos , Contagem de Células , Movimento Celular , Centrifugação com Gradiente de Concentração/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fagocitose/fisiologia , Povidona , Espécies Reativas de Oxigênio/metabolismo , Dióxido de Silício , Adulto Jovem
14.
Dev Cell ; 12(3): 326-7, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17336899
15.
Nat Cell Biol ; 7(9): 887-93, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16086013

RESUMO

Rab-family GTPases are conserved regulators of membrane trafficking that cycle between inactive GDP-bound and activated GTP-bound states. A key determinant of Rab function is the lifetime of the GTP-bound state. As Rabs have a low intrinsic rate of GTP hydrolysis, this process is under the control of GTP-hydrolysis-activating proteins (GAPs). Due to the large number of Rabs and GAPs that are encoded by the human genome, it has proven difficult to assign specific functional relationships to these proteins. Here, we identify a Rab5-specific GAP (RabGAP-5), and show that RN-Tre (previously described as a Rab5 GAP) acts on Rab41. RabGAP-5 overexpression triggers a loss of the Rab5 effector EEA1 from endosomes and blocks endocytic trafficking. By contrast, depletion of RabGAP-5 results in increased endosome size, more endosome-associated EEA1, and disrupts the trafficking of EGF and LAMP1. RabGAP-5 therefore limits the amount of activated Rab5, and thereby regulates trafficking through endosomes.


Assuntos
Membrana Celular/metabolismo , Endocitose/fisiologia , Endossomos/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Proteínas rab5 de Ligação ao GTP/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Regulação para Baixo/fisiologia , Fator de Crescimento Epidérmico/metabolismo , Proteínas Ativadoras de GTPase/genética , Proteínas Ativadoras de GTPase/isolamento & purificação , Células HeLa , Humanos , Proteínas de Membrana Lisossomal , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Transporte Proteico/fisiologia , Proteínas de Transporte Vesicular , Proteínas rab de Ligação ao GTP/metabolismo
16.
J Cell Biol ; 178(3): 363-9, 2007 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-17646400

RESUMO

Primary cilia are sensory structures involved in morphogen signalling during development, liquid flow in the kidney, mechanosensation, sight, and smell (Badano, J.L., N. Mitsuma, P.L. Beales, and N. Katsanis. 2006. Annu. Rev. Genomics Hum. Genet. 7:125-148; Singla, V., and J.F. Reiter. 2006. Science. 313:629-633.). Mutations that affect primary cilia are responsible for several diseases, including neural tube defects, polycystic kidney disease, retinal degeneration, and cancers (Badano et al., 2006; Singla and Reiter, 2006). Primary cilia formation and function requires tight integration of the microtubule cytoskeleton with membrane trafficking (Singla and Reiter, 2006), and this is poorly understood. We show that the Rab GTPase membrane trafficking regulators Rab8a, -17, and -23, and their cognate GTPase-activating proteins (GAPs), XM_037557, TBC1D7, and EVI5like, are involved in primary cilia formation. However, other human Rabs and GAPs are not. Additionally, Rab8a specifically interacts with cenexin/ODF2, a basal body and microtubule binding protein required for cilium biogenesis (Ishikawa, H., A. Kubo, S. Tsukita, and S. Tsukita. 2005. Nat. Cell Biol. 7:517-524), and is the sole Rab enriched at primary cilia. These findings provide a basis for understanding how specific membrane trafficking pathways cooperate with the microtubule cytoskeleton to give rise to the primary cilia.


Assuntos
Cílios/metabolismo , Células Receptoras Sensoriais/metabolismo , Transdução de Sinais/fisiologia , Proteínas rab de Ligação ao GTP/metabolismo , Animais , Células Cultivadas , Citoesqueleto/metabolismo , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Microtúbulos/metabolismo , Dados de Sequência Molecular , Epitélio Pigmentado Ocular/citologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas rab de Ligação ao GTP/genética
17.
J Cell Biol ; 177(6): 1133-43, 2007 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-17562788

RESUMO

Rab family guanosine triphosphatases (GTPases) together with their regulators define specific pathways of membrane traffic within eukaryotic cells. In this study, we have investigated which Rab GTPase-activating proteins (GAPs) can interfere with the trafficking of Shiga toxin from the cell surface to the Golgi apparatus and studied transport of the epidermal growth factor (EGF) from the cell surface to endosomes. This screen identifies 6 (EVI5, RN-tre/USP6NL, TBC1D10A-C, and TBC1D17) of 39 predicted human Rab GAPs as specific regulators of Shiga toxin but not EGF uptake. We show that Rab43 is the target of RN-tre and is required for Shiga toxin uptake. In contrast, RabGAP-5, a Rab5 GAP, was unique among the GAPs tested and reduced the uptake of EGF but not Shiga toxin. These results suggest that Shiga toxin trafficking to the Golgi is a multistep process controlled by several Rab GAPs and their target Rabs and that this process is discrete from ligand-induced EGF receptor trafficking.


Assuntos
Fator de Crescimento Epidérmico/metabolismo , Proteínas Ativadoras de GTPase/fisiologia , Toxina Shiga/metabolismo , Proteínas rab de Ligação ao GTP/fisiologia , Endossomos/metabolismo , Complexo de Golgi/metabolismo , Humanos , Transporte Proteico
18.
Sci Rep ; 12(1): 12013, 2022 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35853951

RESUMO

Rivers are known to act as biogeographic barriers in several strictly terrestrial taxa, while possibly serving as conduits of dispersal for freshwater-tolerant or -dependent species. However, the influence of river systems on genetic diversity depends on taxa-specific life history traits as well as other geographic factors. In amphibians, several studies have demonstrated that river systems have only minor influence on their divergence. Here, we assess the role of the paleodrainage systems of the Sunda region (with a focus on the island of Sumatra) in shaping the evolutionary history of two genera of frogs (Sumaterana and Wijayarana) whose tadpoles are highly dependent on cascading stream habitats. Our phylogenetic results show no clear association between the genetic diversification patterns of both anurans genera and the existence of paleodrainage systems. Time-calibrated phylogenies and biogeographical models suggest that these frogs colonized Sumatra and diversified on the island before the occurrence of the Pleistocene drainage systems. Both genera demonstrate phylogenetic structuring along a north-south geographic axis, the temporal dynamics of which coincide with the geological chronology of proto Sumatran and -Javan volcanic islands. Our results also highlight the chronic underestimation of Sumatran biodiversity and call for more intense sampling efforts on the island.


Assuntos
Biodiversidade , Evolução Biológica , Animais , Anuros/genética , Larva/genética , Filogenia , Filogeografia
19.
Hippocampus ; 21(2): 220-32, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20082289

RESUMO

The chemokine CXCL10 and its receptor CXCR3 are implicated in various CNS pathologies since interference with CXCL10/CXCR3 signaling alters the onset and progression in various CNS disease models. However, the mechanism and cell-types involved in CXCL10/CXCR3 signaling under pathological conditions are far from understood. Here, we investigated the potential role for CXCL10/CXCR3 signaling in neuronal cell death and glia activation in response to N-methyl-D-aspartic acid (NMDA)-induced excitotoxicity in mouse organotypic hippocampal slice cultures (OHSCs). Our findings demonstrate that astrocytes express CXCL10 in response to excitotoxicity. Experiments in OHSCs derived from CXCL10-deficient (CXCL10(-/-) ) and CXCR3-deficient (CXCR3(-/-) ) revealed that in the absence of CXCL10 or CXCR3, neuronal cell death in the CA1 and CA3 regions was diminished after NMDA-treatment when compared to wild type OHSCs. In contrast, neuronal cell death in the DG region was enhanced in both CXCL10(-/-) and CXCR3(-/-) OHSCs in response to a high (50 µM) NMDA-concentration. Moreover, we show that in the absence of microglia the differential changes in neuronal vulnerability between CXCR3(-/-) and wild type OHSCs are fully abrogated and therefore a prominent role for microglia in this process is suggested. Taken together, our results identify a region-specific role for CXCL10/CXCR3 signaling in neuron-glia and glia-glia interactions under pathological conditions.


Assuntos
Quimiocina CXCL10/fisiologia , Hipocampo/fisiopatologia , Neuroglia/fisiologia , Receptores CXCR3/fisiologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/patologia , Região CA1 Hipocampal/fisiopatologia , Região CA3 Hipocampal/efeitos dos fármacos , Região CA3 Hipocampal/patologia , Região CA3 Hipocampal/fisiopatologia , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Quimiocina CXCL10/deficiência , Quimiocina CXCL10/genética , Giro Denteado/efeitos dos fármacos , Giro Denteado/patologia , Giro Denteado/fisiopatologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , N-Metilaspartato/toxicidade , Neurônios/efeitos dos fármacos , Neurônios/patologia , Receptores CXCR3/deficiência , Receptores CXCR3/genética , Transdução de Sinais
20.
J Morphol ; 282(5): 769-778, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33713040

RESUMO

Tadpoles of the Vampire tree frog Rhacophorus vampyrus differ substantially from other rhacophorid tadpoles, by having profound modifications in external morphology. The morphological peculiarities of this species likely correlate with their arboreal microhabitat and strict oophagous diet. In this work, we examine buccal and musculoskeletal anatomy and compare them to other rhacophorid and egg-eating larvae. The shape and arrangement of cartilages of the lower jaw are unique among tadpoles, and the lack of a palatoquadrate suspensorium is only known in the distantly related macrophagous tadpoles of the dicroglossid Occidozyga baluensis. The cranial musculature is massive, and the morphology of several mandibular, hyoid, and abdominal muscles could be related to the ingestion and transit of large eggs. In the buccal cavity, conspicuous aspects are the absence of ridges and papillae, and the development of a unique glandular zone in the buccal floor. Finally, observations of the skeletal support of keratinized mouthparts allow us to present a topography-based hypothesis of homology of the conspicuous fangs of these tadpoles.


Assuntos
Anuros , Sistema Musculoesquelético , Animais , Arcada Osseodentária , Larva , Crânio
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