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1.
J Fish Biol ; 99(3): 1150-1154, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34076277

RESUMO

An egg of the critically endangered flapper skate Dipturus intermedius was successfully incubated to hatching in captivity in what is believed to be a first for the species. Water conditions (temperature, salinity, flow rate) were recorded, with mean water temperatures ranging from a monthly mean of 8.3 ± 1.2 to 13.2 ± 0.3°C and salinity from a monthly mean of 30.5 ± 1.2 to 36.6 ± 2.3 ppt. Hatching occurred after 534 days, suggesting that flapper skate eggs take c. 5700 growing degree-days to incubate to hatching. The egg's prolonged embryonic development raises concerns about flapper skate eggs' vulnerability to anthropogenic disturbance.


Assuntos
Rajidae , Animais , Desenvolvimento Embrionário , Salinidade , Temperatura , Água
2.
Sci Rep ; 12(1): 16613, 2022 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-36198697

RESUMO

Developments in animal electronic tagging and tracking have transformed the field of movement ecology, but interest is also growing in the contributions of tagged animals to oceanography. Animal-borne sensors can address data gaps, improve ocean model skill and support model validation, but previous studies in this area have focused almost exclusively on satellite-telemetered seabirds and seals. Here, for the first time, we develop the use of benthic species as animal oceanographers by combining archival (depth and temperature) data from animal-borne tags, passive acoustic telemetry and citizen-science mark-recapture records from 2016-17 for the Critically Endangered flapper skate (Dipturus intermedius) in Scotland. By comparing temperature observations to predictions from the West Scotland Coastal Ocean Modelling System, we quantify model skill and empirically validate an independent model update. The results from bottom-temperature and temperature-depth profile validation (5,324 observations) fill a key data gap in Scotland. For predictions in 2016, we identified a consistent warm bias (mean = 0.53 °C) but a subsequent model update reduced bias by an estimated 109% and improved model skill. This study uniquely demonstrates the use of benthic animal-borne sensors and citizen-science data for ocean model validation, broadening the range of animal oceanographers in aquatic environments.


Assuntos
Ciência do Cidadão , Focas Verdadeiras , Animais , Oceanografia , Oceanos e Mares , Temperatura
3.
STAR Protoc ; 2(4): 100897, 2021 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34841273

RESUMO

Spatial analysis of spinal neurons is currently limited by a lack of tools for efficient preparation and imaging of the whole spinal cord (SC) and the absence of a 3D reference atlas. Here, we describe protocols for efficient sectioning of whole SC using SpineRacks and subsequent image registration, atlas mapping, and 3D analysis of cells and projections, using SpinalJ. Together, these tools enable high-throughput analyses of adult mouse SC and direct comparison of spatial information of neurons between animals and studies. For complete details on the use and execution of this protocol, please refer to Fiederling et al. (2021).


Assuntos
Técnicas Histológicas/métodos , Imageamento Tridimensional/métodos , Neurônios/citologia , Software , Medula Espinal , Animais , Atlas como Assunto , Crioultramicrotomia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Medula Espinal/citologia , Medula Espinal/diagnóstico por imagem
4.
Cell Rep Methods ; 1(5)2021 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-34661190

RESUMO

To fill the prevailing gap in methodology for whole spinal cord (SC) analysis, we have (1) designed scaffolds (SpineRacks) that facilitate efficient and ordered cryo-sectioning of the entire SC in a single block, (2) constructed a 3D reference atlas of adult mouse SC, and (3) developed software (SpinalJ) to register images of sections and for standardized analysis of cells and projections in atlas space. We have verified mapping accuracies for known neurons and demonstrated the usefulness of this platform to reveal unknown neuronal distributions. Together, these tools provide high-throughput analyses of whole mouse SC and enable direct comparison of 3D spatial information between animals and studies.


Assuntos
Neurônios , Software , Camundongos , Animais , Neurônios/fisiologia , Medula Espinal/diagnóstico por imagem , Rede Nervosa/fisiologia
5.
Biol Open ; 8(7)2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31208997

RESUMO

BMP7 evokes acute chemotropic PI3K-dependent responses, such as growth cone collapse and monocyte chemotaxis, as well as classical Smad-dependent gene transcription. That these divergent responses can be activated in the same cell raises the question of how the BMP-dependent signaling apparatus is manipulated to produce chemotropic and transcriptional signals. RNA interference and site-directed mutagenesis were used to explore functional and structural BMP receptor requirements for BMP7-evoked chemotropic activity. We show that specific type II BMP receptor subunits, ActRIIA and BMPR2, are required for BMP7-induced growth cone collapse in developing spinal neurons and for chemotaxis of monocytes. Reintroduction of wild-type ActRIIA into monocytic cells lacking endogenous ActRIIA restores BMP7-evoked chemotaxis, whereas expression of an ActRIIA K76A receptor variant fails to rescue. BMP7-evoked Smad-dependent signaling is unaffected by either ActRIIA knockdown or expression of the ActRIIA K76A variant. In contrast, BMP7-evoked PI3K-dependent signaling is significantly disturbed in the presence of ActRIIA K76A. These results support a model for selective engagement of chemotropic BMPs with type II BMP receptors, through specific residues, that results in strict regulation of PI3K-dependent signal transduction.This article has an associated First Person interview with the first author of the paper.

6.
Neuron ; 38(3): 389-401, 2003 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-12741987

RESUMO

During spinal cord development, commissural neurons extend their axons ventrally, away from the roof plate. The roof plate is the source of a diffusible repellent that orients commissural axons in vitro and, thus, may regulate the trajectory of commissural axons in vivo. Of three Bmps expressed in the roof plate, BMP7, but not BMP6 or GDF7, mimics the roof plate activity in vitro. We show here that expression of both Bmp7 and Gdf7 by roof plate cells is required for the fidelity of commissural axon growth in vivo. We also demonstrate that BMP7 and GDF7 heterodimerize in vitro and that, under these conditions, GDF7 enhances the axon-orienting activity of BMP7. Our findings suggest that a GDF7:BMP7 heterodimer functions as a roof plate-derived repellent that establishes the initial ventral trajectory of commissural axons.


Assuntos
Proteínas Morfogenéticas Ósseas/deficiência , Cones de Crescimento/metabolismo , Medula Espinal/embriologia , Medula Espinal/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Padronização Corporal/genética , Proteínas Morfogenéticas Ósseas/genética , Células COS , Comunicação Celular/genética , Diferenciação Celular/genética , Quimiotaxia/genética , Dimerização , Feto , Lateralidade Funcional/genética , Cones de Crescimento/ultraestrutura , Fatores de Diferenciação de Crescimento , Proteínas de Homeodomínio/genética , Imuno-Histoquímica , Fator de Transcrição MSX1 , Substâncias Macromoleculares , Camundongos , Camundongos Knockout , Mutação/genética , Medula Espinal/citologia , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética
8.
Neural Dev ; 7: 16, 2012 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-22559862

RESUMO

BACKGROUND: In dorsal spinal neurons and monocytes, bone morphogenetic protein (BMP)7 activates distinct transduction pathways, one leading to inductive specification and the other to axon orientation and chemotaxis. BMP7-evoked induction, also stimulated by the closely related BMP6, acts through a Smad cascade, leading to nuclear signaling, and is not BMPR subunit selective. Orientation is evoked by BMP7, but not by BMP6, through PI3K-dependent cytoskeletal activation mediated by the type II BMPRs, ActRIIA and BMPRII and is independent of the Smad cascade. The responses can be stimulated concurrently and suggest that BMP7, but not BMP6, can selectively activate BMPR subunits that engage the divergent paths. Although structural and biochemical analyses of selected BMP/BMPR interfaces have identified key regions of interaction, how these translate into function by related BMPs is poorly understood. To determine the mechanisms underlying the distinct activities of BMP7 and the disparate properties of BMP7 and BMP6 in spinal cord development, we have performed a family-wide structure/function analysis of BMPs and used the information to predict and test sites within BMPs that may control agonist properties, in particular the ability of a BMP to orient axons, through interactions with BMPRs. RESULTS: We demonstrate that whereas all BMPs can induce dorsal neurons, there is selectivity in the ability also to orient axons or evoke growth cone collapse. The degree to which a BMP orients is not predictable by overall protein similarity with other BMPs but comparison of sequences of potent and weakly orienting BMPs with that of the non-orienting BMP6 revealed three candidate positions within the BMPs at which the amino acid residues may confer or obstruct orienting ability. Residue swapping analysis has identified one residue, Gln48 in BMP6, that blocks axon orienting ability. Replacing Gln48 with any of the amino acids present at the equivalent residue position in the orienting subset of BMPs confers orienting activity on BMP6. Conversely, swapping Gln48 into BMP7 reduces orienting ability. The inductive capacity of the BMPs was unchanged by these residue swaps. CONCLUSIONS: The results suggest that the presence of the Gln48 residue in BMP6 is structurally inhibitory for BMP/BMPR interactions that result in the activation of intracellular signaling, leading to axon orientation. Moreover, since residue 48 in BMP7 and the corresponding residue in BMP2 are important for type II BMPR binding, our results provide a basis for a mechanistic understanding of the diverse activities of BMPs in spinal cord development.


Assuntos
Proteínas Morfogenéticas Ósseas/genética , Proteínas Morfogenéticas Ósseas/metabolismo , Neurônios/metabolismo , Transdução de Sinais , Sequência de Aminoácidos , Animais , Axônios/patologia , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/metabolismo , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/metabolismo , Proteínas Morfogenéticas Ósseas/química , Células Cultivadas , Cones de Crescimento/patologia , Camundongos , Dados de Sequência Molecular , Medula Espinal/citologia
9.
Neural Dev ; 6: 36, 2011 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22085733

RESUMO

BACKGROUND: Bone morphogenetic protein (BMP)7 evokes both inductive and axon orienting responses in dorsal interneurons (dI neurons) in the developing spinal cord. These events occur sequentially during the development of spinal neurons but in these and other cell types such inductive and acute chemotactic responses occur concurrently, highlighting the requirement for divergent intracellular signaling. Both type I and type II BMP receptor subtypes have been implicated selectively in orienting responses but it remains unclear how, in a given cell, divergence occurs. We have examined the mechanisms by which disparate BMP7 activities are generated in dorsal spinal neurons. RESULTS: We show that widely different threshold concentrations of BMP7 are required to elicit the divergent inductive and axon orienting responses. Type I BMP receptor kinase activity is required for activation of pSmad signaling and induction of dI character by BMP7, a high threshold response. In contrast, neither type I BMP receptor kinase activity nor Smad1/5/8 phosphorylation is involved in the low threshold orienting responses of dI axons to BMP7. Instead, BMP7-evoked axonal repulsion and growth cone collapse are dependent on phosphoinositide-3-kinase (PI3K) activation, plausibly through type II receptor signaling. BMP7 stimulates PI3K-dependent signaling in dI neurons. BMP6, which evokes neural induction but does not have orienting activity, activates Smad signaling but does not stimulate PI3K. CONCLUSIONS: Divergent signaling through pSmad-dependent and PI3K-dependent (Smad-independent) mechanisms mediates the inductive and orienting responses of dI neurons to BMP7. A model is proposed whereby selective engagement of BMP receptor subunits underlies choice of signaling pathway.


Assuntos
Proteína Morfogenética Óssea 7/farmacologia , Receptores de Proteínas Morfogenéticas Ósseas/metabolismo , Interneurônios/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Smad/metabolismo , Animais , Axônios/metabolismo , Proteína Morfogenética Óssea 6/farmacologia , Receptores de Proteínas Morfogenéticas Ósseas Tipo I/metabolismo , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/metabolismo , Quimiotaxia/efeitos dos fármacos , Feminino , Cones de Crescimento/ultraestrutura , Interneurônios/enzimologia , Interneurônios/ultraestrutura , Neurônios/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Transdução de Sinais/fisiologia , Medula Espinal/citologia , Medula Espinal/embriologia
10.
PLoS One ; 4(12): e8198, 2009 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-20011660

RESUMO

Bone morphogenetic protein (BMP)-evoked reorientation and chemotaxis of cells occurs with rapid onset and involves events local to the cell membrane. The signaling pathways underlying these rapid processes likely diverge from those mediating classical transcriptional responses to BMPs but it remains unclear how BMP receptors are utilized to generate distinct intracellular mechanisms. We show that BMP7-evoked chemotaxis of monocytic cells depends on the activity of canonical type II BMP receptors. Although the three canonical type II BMP receptors are expressed in monocytic cells, inhibition of receptor subunit expression by RNAi reveals that ActRIIA and BMPRII, but not ActRIIB, are each essential for BMP7-evoked chemotaxis but not required individually for BMP-mediated induction. Furthermore, the chemotactic response to BMP7 does not involve canonical Smad4-dependent signaling but acts through PI3K-dependent signaling, illustrating selective activation of distinct intracellular events through differential engagement of receptors. We suggest a model of a BMP receptor complex in which the coordinated activity of ActRIIA and BMPRII receptor subunits selectively mediates the chemotactic response to BMP7.


Assuntos
Receptores de Activinas Tipo II/metabolismo , Proteína Morfogenética Óssea 7/farmacologia , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/metabolismo , Quimiotaxia/efeitos dos fármacos , Subunidades Proteicas/metabolismo , Animais , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/genética , Linhagem Celular , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Modelos Biológicos , Monócitos/citologia , Monócitos/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno , Transdução de Sinais/efeitos dos fármacos , Proteína Smad4/metabolismo
11.
Neuron ; 59(3): 413-24, 2008 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-18701067

RESUMO

Despite increasing evidence for transcriptional control of neural connectivity, how transcription factors regulate discrete steps in axon guidance remains obscure. Projection neurons in the dorsal spinal cord relay sensory signals to higher brain centers. Some projection neurons send their axons ipsilaterally, whereas others, commissural neurons, send axons contralaterally. We show that two closely related LIM homeodomain proteins, Lhx2 and Lhx9, are expressed by a set of commissural relay neurons (dI1c neurons) and are required for the dI1c axon projection. Midline crossing by dI1c axons is lost in Lhx2/9 double mutants, a defect that results from loss of expression of Rig-1 from dI1c axons. Lhx2 binds to a conserved motif in the Rig-1 gene, suggesting that Lhx2/9 regulate directly the expression of Rig-1. Our findings reveal a link between the transcriptional programs that define neuronal subtype identity and the expression of receptors that guide distinctive aspects of their trajectory.


Assuntos
RNA Helicases DEAD-box/metabolismo , Lateralidade Funcional/fisiologia , Proteínas de Homeodomínio/metabolismo , Neurônios Aferentes/fisiologia , Medula Espinal/citologia , Fatores de Transcrição/metabolismo , Vias Aferentes/fisiologia , Animais , Axônios/metabolismo , Proteína DEAD-box 58 , Embrião de Mamíferos , Regulação da Expressão Gênica/genética , Proteínas de Fluorescência Verde , Proteínas de Homeodomínio/genética , Proteínas com Homeodomínio LIM , Camundongos , Camundongos Transgênicos , Modelos Neurológicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neurônios Aferentes/classificação , Neurônios Aferentes/citologia , Fatores de Transcrição/genética
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