RESUMEN
RESUMEN: El uso de plataformas virtuales se muestra como un nuevo recurso didáctico que posibilita el proceso de enseñanza-aprendizaje de forma dinámica. A grandes rasgos, permite el acceso a imágenes digitales en alta resolución mediante el uso de computadores, smartphones y/o tabletas. Portanto, este trabajo presenta nuestra metodología en el campo de la embriología de aves domésticas y la experiencia adquirida en el desarrollo de recursos para la enseñanza por medio de las tecnologías de la información y comunicación, de gran utilidad hoy en día en medio de la pandemia ocasionada por el nuevo coronavirus.
SUMMARY: Online platforms are a new didactic resource that enable an active teaching-learning process. In general, they allows access to high resolution digital images through the use of computers, smartphones and / or tablets. Therefore, this study presents our methodology in the field of domestic bird embryology and the experience acquired in the development of teaching resources through information and communication technologies, which are very useful nowadays, particularly in the midst of the pandemic caused by the new coronavirus.
Asunto(s)
Animales , Interfaz Usuario-Computador , Embrión de Pollo/anatomía & histología , Embriología/educación , Educación a Distancia , Aves/embriología , Internet , Tecnología de la InformaciónRESUMEN
Cardiac malformations are very prevalent and can be caused both by defective genes and envi-ronmental teratogens. Among the latter, caffeine causes malformations when exposed during early cardiac development, whereas its later effects are still unclear. We exposed three-day incubated (D3) chick embryos to 2 mg caffeine and analyzed them at D5, D7 and D9. The embryos were serially sec-tioned and analyzed two-dimensionally. Alternatively, the sections of D9 embryos were reconstructed three-dimensionally using Amira® software and analyzed volumetrically. The expres-sion of genes involved in endothelial-mesenchymal transformation (EMT) was studied by real-time PCR. Interestingly, caffeine treatment at D3 em-bryos did not induce cardiac malformations, but did delay growth, in particular that of the ventricles and ventricular trabeculae. Furthermore, it affected EMT in the endocardial cushion and atrioventricu-lar valves. Gene-expression analysis revealed that caffeine had a progressively deleterious effect on the expressions of GATA4, MMP2, SNAIL1, TWIST1, and VIMENTIN. The effect of late caf-feine administration on the chicken embryos would provide suggestive evident towards a possible heart developmental defect in humans, particularly heavy caffeine consumers during pregnancy
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Animales , Embrión de Pollo/efectos de los fármacos , Cafeína/administración & dosificación , Cardiopatías Congénitas/inducido químicamente , Cardiopatías Congénitas/genética , Embrión de Pollo/anatomía & histología , Desarrollo Embrionario/efectos de los fármacos , Desarrollo Embrionario/genética , Análisis de Datos , Volumetría/métodos , Ecocardiografía Tridimensional , Anatomía TransversalRESUMEN
The chick immune system is a fundamental model in basic immunology. In birds, the bone marrow derived pluripotent stem cells after entering the circulation, migrate to bursa of Fabricius to benefit from a microenvironment which supports the differentiation and maturation of B lymphocytes by the help of its resident cells and tissues. Delivering sufficient functional B cells is required to maintain their peripheral population and normal peripheral humoral responses. Additionally, bursa acts as an active site for the generation of antibody diversity through gene conversion. Being consisted of 98% B lymphocytes, the organ is occupied by other cell types including T cells, macrophages, eosinophils and mast cells. Thymus, which is an epithelial organ is the main site of T cell development where positive and negative selections contribute to the development of functional and not autoreactive T cell repertoire. Bursectomy and thymectomy are surgical exercises through which the involvement of cells of specific immunity including B cells and T cells can be determined.
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Embrión de Pollo/inmunología , Pollos/anatomía & histología , Pollos/inmunología , Sistema Inmunológico/embriología , Morfogénesis/fisiología , Animales , Linfocitos B/citología , Linfocitos B/fisiología , Células de la Médula Ósea/citología , Células de la Médula Ósea/fisiología , Bolsa de Fabricio/citología , Bolsa de Fabricio/inmunología , Diferenciación Celular/inmunología , Embrión de Pollo/anatomía & histología , Embrión de Pollo/embriología , Sistema Inmunológico/anatomía & histología , Morfogénesis/inmunologíaRESUMEN
The aim of this study was to observe morphological changes of the cultured otocysts isolated from various stages of the chick embryo. Isolated otocysts were dissected from embryonic day, E2.5-4.5 of incubation (HH stage 16-26) according to stages of developing inner ear. Morphology of the chick otocyst exhibited an ovoid shape. The width and height of the otocyst were 0.2 mm and 0.3 mm, respectively. Elongation of a tube-like structure, the endolymphatic duct, was found at the dorsal aspect of the otocyst. The cultured otocyst is lined by the otic epithelium and surrounding periotic mesenchymal cells started to migrate outwards the lateral aspect of such epithelium. Notably, the acoustic-vestibular ganglion (AVG) was observed at the ventrolateral aspect of the otocyst. Appearance of AVG in vitro can be applied for studying chemical-induced ototoxicity and sensorineural hearing loss. It was concluded that the organ-cultured otocyst of the chick embryo could be used as a model to study sensory organ development of avian inner ear.
El objetivo de este estudio fue observar los cambios morfológicos de otocistos cultivados aislados en las diversas etapas del desarrollo del embrión de pollo. Otocistos aislados fueron obtenidos de embriones día, E2.5-4.5 de incubación (HH etapa 16-26) de acuerdo a las etapas de desarrollo del oído interno. El otocisto de pollo presentó una morfología ovoide. El ancho y la altura del otocisto fue de 0,2 mm y 0,3 mm, respectivamente. En la cara dorsal del otocisto se visualizó el alargamiento de una estructura similar a un tubo, el conducto endolinfático. El otocisto cultivado está revestido por epitelio ótico y células mesenquimatosas perióticas que comienzan a migrar hacia el exterior de la cara lateral en búsqueda del epitelio. En particular, el ganglio acústico-vestibular (GAV) fue observado en la parte ventrolateral del otocisto. La aparición de GAV in vitro puede ser aplicado para el estudio de la ototoxicidad inducida por productos químicos y la pérdida de audición neurosensorial. Se concluyó que el otocisto cultivado de embrión de pollo podría ser utilizado como un modelo para estudiar el desarrollo de órganos sensoriales del oído interno aviar.
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Animales , Embrión de Pollo/anatomía & histología , Oído Interno/embriología , MorfogénesisRESUMEN
The transcription factor Nr4a2 was recently revealed as a very early developmental marker of the claustrum (CL) proper in the mouse. The earliest claustral primordium was identified superficially, dorsal to the olfactory cortex, and was subsequently covered by the Nr4a2-negative cells of the insular cortex. Some tangentially migrating claustral derivatives (subplate cells and some endopiriform elements) also expressed this marker. The present study employs the same genetic marker to explore the presence of a comparable pallial division in chicken in which, in principle, the same pallial sectors exist as in mammals. We were indeed able to delineate an early-developing Nr4a2-positive mantle domain at the expected topologic position within the developing chicken lateral pallium. In the chicken as well as in the turtle (from data in the literature), the earliest postmitotic lateropallial cells likewise express Nr4a2 and occupy a corticoid superficial stratum of the mesopallium, which is clearly comparable in spatial and chronological profile to the mouse CL. Other cells produced in this pallial sector include various tangentially migrating Nr4a2-labeled derivatives as well as Nr4a2-negative and Nr4a2-positive local deeper subpopulations that partially interdigitate, forming mesopallial core and shell populations. We hold that the deep avian and reptilian mesopallial formation developing under the superficial corticoid CL homolog represents a field homolog of the insula, although additional studies are required to underpin this hypothesis.
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Proteínas Aviares/metabolismo , Embrión de Pollo/anatomía & histología , Embrión de Pollo/metabolismo , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Telencéfalo/anatomía & histología , Telencéfalo/embriología , Animales , Evolución Biológica , Hibridación in Situ , Ratones , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Especificidad de la Especie , Telencéfalo/metabolismo , TortugasRESUMEN
From early dinosaurs with as many as nine wrist bones, modern birds evolved to develop only four ossifications. Their identity is uncertain, with different labels used in palaeontology and developmental biology. We examined embryos of several species and studied chicken embryos in detail through a new technique allowing whole-mount immunofluorescence of the embryonic cartilaginous skeleton. Beyond previous controversy, we establish that the proximal-anterior ossification develops from a composite radiale+intermedium cartilage, consistent with fusion of radiale and intermedium observed in some theropod dinosaurs. Despite previous claims that the development of the distal-anterior ossification does not support the dinosaur-bird link, we found its embryonic precursor shows two distinct regions of both collagen type II and collagen type IX expression, resembling the composite semilunate bone of bird-like dinosaurs (distal carpal 1+distal carpal 2). The distal-posterior ossification develops from a cartilage referred to as "element x," but its position corresponds to distal carpal 3. The proximal-posterior ossification is perhaps most controversial: It is labelled as the ulnare in palaeontology, but we confirm the embryonic ulnare is lost during development. Re-examination of the fossil evidence reveals the ulnare was actually absent in bird-like dinosaurs. We confirm the proximal-posterior bone is a pisiform in terms of embryonic position and its development as a sesamoid associated to a tendon. However, the pisiform is absent in bird-like dinosaurs, which are known from several articulated specimens. The combined data provide compelling evidence of a remarkable evolutionary reversal: A large, ossified pisiform re-evolved in the lineage leading to birds, after a period in which it was either absent, nonossified, or very small, consistently escaping fossil preservation. The bird wrist provides a modern example of how developmental and paleontological data illuminate each other. Based on all available data, we introduce a new nomenclature for bird wrist ossifications.
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Evolución Biológica , Carpo Animal/anatomía & histología , Embrión de Pollo/anatomía & histología , Dinosaurios/anatomía & histología , Animales , Carpo Animal/metabolismo , Cartílago/anatomía & histología , Cartílago/fisiología , Embrión de Pollo/metabolismo , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Colágeno Tipo IX/genética , Colágeno Tipo IX/metabolismo , Dinosaurios/clasificación , Dinosaurios/fisiología , Fósiles , Expresión Génica , Paleontología , Tendones/anatomía & histología , Tendones/fisiología , Alas de Animales/anatomía & histología , Alas de Animales/fisiologíaRESUMEN
1. The objective of the study was to investigate the effects of breeder age and egg weight on hatching performance and morphological changes in segments of the small intestine of broiler chicks during a 21 h hatch window. 2. Eggs from Ross broiler breeder flocks aged 29 (young) and 48 weeks (old) were classified as light (LE) or heavy (HE) and incubated at the same conditions. At 475 h of incubation, eggs were checked every 3 h to determine time of external pipping and hatching. The first 42 chicks to emerge from each group were weighed and chick length was measured and 14 chicks from each group were sampled to collect residual yolk and intestine segments. The rest of chicks were placed back in the incubator and chick weight and length were measured individually at 9, 15 and 21 h after chicks hatched. At the end of 21 h, 14 chicks from each group were sampled again and the same procedure was followed. 3. The HE chicks pipped and hatched later than LE, regardless of breeder age. From hatch to the end of the hatch window, chick weight, but not yolk-free chick weight, gradually reduced. Relative residual yolk weight of chicks from both egg weights was similar at hatch, however, yolk sac utilisation was higher for LE chicks during the 21 h post-hatch period. At hatch, jejunum and ileum villus development was very similar for HE and LE chicks but greater development was observed for villus area with an increase in the jejunum villus length, width and goblet cell numbers in HE chicks. 4. The longest jejunum villus and the widest duodenum and jejunum villus were obtained for HE chicks from old breeders indicating that HE chicks from old breeders would have a greater surface area for nutrient absorption.
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Pollos/anatomía & histología , Pollos/fisiología , Íleon/anatomía & histología , Yeyuno/anatomía & histología , Reproducción , Factores de Edad , Animales , Peso Corporal , Embrión de Pollo/anatomía & histología , Embrión de Pollo/crecimiento & desarrollo , Embrión de Pollo/fisiología , Pollos/crecimiento & desarrollo , Femenino , Íleon/crecimiento & desarrollo , Yeyuno/crecimiento & desarrollo , Óvulo/fisiologíaRESUMEN
The poultry industry is a sector of agribusiness which represents an important role in the country's agricultural exports. Therefore, the study about embryogenesis of the domestic chicken (Gallus gallus domesticus) has a great economic importance. The aim of this study was to evaluate embryonic development of the endoderm in chicken (Gallus gallus domesticus). Forty fertilized eggs of domestic chickens, starting from the 1st day of gestation and so on until the 19 days of the incubation were collected from the Granja São José (Amparo, SP, Brazil). Embryos and fetus were fixed in 10% formaldehyde solution, identified, weighed, measured, and subjected to light and scanning electron microscopy. The endoderm originates the internal lining epithelium of the digestive, immune, respiratory systems, and the organs can be visualized from the second day (48 h) when the liver is formed. The formation of the digestive system was complete in the 12th day. Respiratory system organs begin at the fourth day as a disorganized tissue and undifferentiated. Their complete differentiation was observed at the 10 days of incubation, however, until the 19 days the syrinx was not observed. The formation of immune system at 10th day was observed with observation of the spleen, thymus, and cloacal bursa. The study of the organogenesis of the chicken based on germ layers is very complex and underexplored, and the study of chicken embryology is very important due the economic importance and growth of the use of this animal model studies such as genetic studies.
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Embrión de Pollo/embriología , Desarrollo Embrionario , Endodermo/embriología , Animales , Embrión de Pollo/anatomía & histología , Embrión de Pollo/ultraestructura , Pollos/anatomía & histología , Pollos/crecimiento & desarrollo , Endodermo/anatomía & histología , Endodermo/ultraestructura , Hígado/anatomía & histología , Hígado/embriología , Hígado/ultraestructura , Microscopía Electrónica de Rastreo , Bazo/anatomía & histología , Bazo/embriología , Bazo/ultraestructuraRESUMEN
The embryonic chick is a widely used model for the study of peripheral and central ganglion cell projections. In the auditory system, selective labeling of auditory axons within the VIIIth cranial nerve would enhance the study of central auditory circuit development. This approach is challenging because multiple sensory organs of the inner ear contribute to the VIIIth nerve (1). Moreover, markers that reliably distinguish auditory versus vestibular groups of axons within the avian VIIIth nerve have yet to be identified. Auditory and vestibular pathways cannot be distinguished functionally in early embryos, as sensory-evoked responses are not present before the circuits are formed. Centrally projecting VIIIth nerve axons have been traced in some studies, but auditory axon labeling was accompanied by labeling from other VIIIth nerve components (2,3). Here, we describe a method for anterograde tracing from the acoustic ganglion to selectively label auditory axons within the developing VIIIth nerve. First, after partial dissection of the anterior cephalic region of an 8-day chick embryo immersed in oxygenated artificial cerebrospinal fluid, the cochlear duct is identified by anatomical landmarks. Next, a fine pulled glass micropipette is positioned to inject a small amount of rhodamine dextran amine into the duct and adjacent deep region where the acoustic ganglion cells are located. Within thirty minutes following the injection, auditory axons are traced centrally into the hindbrain and can later be visualized following histologic preparation. This method provides a useful tool for developmental studies of peripheral to central auditory circuit formation.
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Embrión de Pollo/anatomía & histología , Nervio Vestibulococlear/embriología , Animales , Axones/química , Conducto Coclear/embriología , Conducto Coclear/inmunología , Conducto Coclear/cirugía , Dextranos/química , Disección/métodos , Ganglios/citología , Ganglios/embriología , Rodaminas/química , Nervio Vestibulococlear/anatomía & histologíaRESUMEN
The objective of this study was to examine the effect of embryonic nutritional enrichment on the development and properties of broiler leg bones (tibia and femur) from the prenatal period until maturity. To accomplish the objective, 300 eggs were divided into 2 groups: a noninjected group (control) and a group injected in ovo with a solution containing minerals, vitamins, and carbohydrates (enriched). Tibia and femur from both legs were harvested from chicks on embryonic days 19 (E19) and 21 (E21) and d 3, 7, 14, 28, and 54 posthatch (n = 8). The bones were mechanically tested (stiffness, maximal load, and work to fracture) and scanned in a micro-computed tomography (µCT) scanner to examine the structural properties of the cortical [cortical area, medullary area, cortical thickness, and maximal moment of inertia (Imax)] and trabecular (bone volume percent, trabecular thickness, and trabecular number) areas. To examine bone mineralization, bone mineral density (BMD) of the cortical area was obtained from the µCT scans, and bones were analyzed for the ash and mineral content. The results showed improved mechanical properties of the enriched group between E19 and d 3 and on d 14 (P < 0.05). Differences in cortical morphology were noted between E19 and d 14 as the enriched group had greater medullary area on E19 (femur), reduced medullary area on E21 (both bones), greater femoral cortical area on d 3, and greater Imax of both bones on d 14 (P < 0.05). The major differences in bone trabecular architecture were that the enriched group had greater bone volume percent and trabecular thickness in the tibia on d 7 and the femur on d 28 (P < 0.05). The pattern of mineralization between E19 and d 54 showed improved mineralization in the enriched group on E19 whereas on d 3 and 7, the control group showed a mineralization advantage, and on d 28 and 54, the enriched group showed again greater mineralization (P < 0.05). In summary, this study demonstrated that in ovo enrichment affects multiple bone properties pre- and postnatally and showed that avian embryos are a good model for studying the effect of embryonic nutrition on natal and postnatal development. Most importantly, the enrichment led to improved mechanical properties until d 14 (roughly third of the lifespan of the bird), a big advantage for the young broiler. Additionally, the improved mineralization and trabecular architecture on d 28 and 54 indicate a potential long-term effect of altering embryonic nutrition.
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Pollos/fisiología , Carbohidratos de la Dieta/administración & dosificación , Fémur/crecimiento & desarrollo , Minerales/administración & dosificación , Tibia/crecimiento & desarrollo , Vitaminas/administración & dosificación , Envejecimiento , Animales , Fenómenos Biomecánicos , Densidad Ósea , Calcificación Fisiológica , Embrión de Pollo/anatomía & histología , Embrión de Pollo/fisiología , Pollos/anatomía & histología , Pollos/crecimiento & desarrollo , Suplementos Dietéticos/análisis , Fémur/anatomía & histología , Fémur/fisiología , Tibia/anatomía & histología , Tibia/fisiología , Tomografía Computarizada por Rayos X/veterinariaRESUMEN
Vertebrates have achieved great evolutionary success due in large part to the anatomical diversification of their jaw complex, which allows them to inhabit almost every ecological niche. While many studies have focused on mechanisms that pattern the jaw skeleton, much remains to be understood about the origins of novelty and diversity in the closely associated musculature. To address this issue, we focused on parrots, which have acquired two anatomically unique jaw muscles: the ethmomandibular and the pseudomasseter. In parrot embryos, we observe distinct and highly derived expression patterns for Scx, Bmp4, Tgfß2 and Six2 in neural crest-derived mesenchyme destined to form jaw muscle connective tissues. Furthermore, immunohistochemical analysis reveals that cell proliferation is more active in the cells within the jaw muscle than in surrounding connective tissue cells. This biased and differentially regulated mode of cell proliferation in cranial musculoskeletal tissues may allow these unusual jaw muscles to extend towards their new attachment sites. We conclude that the alteration of neural crest-derived connective tissue distribution during development may underlie the spatial changes in jaw musculoskeletal architecture found only in parrots. Thus, parrots provide valuable insights into molecular and cellular mechanisms that may generate evolutionary novelties with functionally adaptive significance.
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Músculos Masticadores/embriología , Músculos Masticadores/metabolismo , Cresta Neural/embriología , Cresta Neural/metabolismo , Loros/embriología , Loros/metabolismo , Animales , Evolución Biológica , Proteína Morfogenética Ósea 4/metabolismo , Proliferación Celular , Embrión de Pollo/anatomía & histología , Embrión de Pollo/metabolismo , Pollos/anatomía & histología , Pollos/genética , Pollos/metabolismo , Embrión no Mamífero/anatomía & histología , Embrión no Mamífero/embriología , Embrión no Mamífero/metabolismo , Factor 8 de Crecimiento de Fibroblastos/metabolismo , Regulación del Desarrollo de la Expresión Génica , Procesamiento de Imagen Asistido por Computador , Maxilares/anatomía & histología , Maxilares/embriología , Músculos Masticadores/anatomía & histología , Desarrollo Maxilofacial , Mesodermo/anatomía & histología , Mesodermo/citología , Mesodermo/embriología , Mesodermo/metabolismo , Cresta Neural/citología , Loros/anatomía & histología , Loros/genética , Codorniz/anatomía & histología , Codorniz/embriología , Codorniz/genética , Codorniz/metabolismo , Cráneo/citología , Cráneo/embriología , Factor de Crecimiento Transformador beta2/metabolismoRESUMEN
The embryonic chick occupies a privileged place among animal models used in developmental studies. Its rapid development and accessibility for visualization and experimental manipulation are just some of the characteristics that have made it a vertebrate model of choice for more than two millennia. Until a few years ago, the inability to perform genetic manipulations constituted a major drawback of this system. However, the completion of the chicken genome project and the development of techniques to manipulate gene expression have allowed this classic animal model to enter the molecular age. Such techniques, combined with the embryological manipulations that this system is well known for, provide a unique toolkit to study the genetic basis of neural development. A major advantage of these approaches is that they permit targeted gene misexpression with extremely high spatiotemporal resolution and over a large range of developmental stages, allowing functional analysis at a level, speed and ease that is difficult to achieve in other systems. This article provides a general overview of the chick as a developmental model focusing more specifically on its application to the study of eye development. Special emphasis is given to the state of the art of the techniques that have made gene gain- and loss-of-function studies in this model a reality. In addition, we discuss some methodological considerations derived from our own experience that we believe will be beneficial to researchers working with this system.
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Embrión de Pollo/anatomía & histología , Embrión de Pollo/fisiología , Retina/embriología , Retina/crecimiento & desarrollo , Animales , Modelos AnimalesRESUMEN
The anterior border of the neural plate, presumed to contain the prospective peripheral portion (roof) of the prospective telencephalon, emerges within a vaguely defined proneural ectodermal region. Fate maps carried out at HH4 in the chick reveal that this region still produces indistinctly neural, placodal and non-neural derivatives; it does not express neural markers. We examined how the definitive anterior border domain of the rostral forebrain becomes established and comes to display a neural molecular profile, whereas local non-neural derivatives become separated. The process, interpreted as a border sharpening mechanism via intercalatory cell movements, was studied using fate mapping, time-lapse microscopy and in situ hybridization. Separation of neural and non-neural domains proceeds along stages HH4-HH4+, is well advanced at HH5, and is accompanied by a novel dorsoventral intercalation, oriented orthogonal to the border, that distributes transitional cells into molecularly distinct neural and non-neural fields. Meanwhile, neuroectodermal Sox2 expression spreads peripherally from the neighbourhood of the node, reaching the nascent anterior border domain at HH5. We also show that concurrent signals from the endodermal layer are necessary to position and sharpen the neural border, and suggest that FGF8 might be a component of this signalling.
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Embrión de Pollo , Endodermo/citología , Endodermo/fisiología , Morfogénesis/fisiología , Placa Neural/anatomía & histología , Placa Neural/fisiología , Transducción de Señal/fisiología , Animales , Movimiento Celular , Embrión de Pollo/anatomía & histología , Embrión de Pollo/fisiología , Factor 8 de Crecimiento de Fibroblastos/genética , Factor 8 de Crecimiento de Fibroblastos/metabolismo , Regulación del Desarrollo de la Expresión Génica , Sistema Nervioso , Factores de Transcripción SOXB1/genética , Factores de Transcripción SOXB1/metabolismoRESUMEN
The effects of the in ovo injection of different carbohydrate solutions on the internal egg temperature (IT), hatchability, and time of hatch of embryonated Ross × Ross 708 broiler hatching eggs were determined. In addition, the BW, liver weight, yolk sac weight (YSW), and yolk-free BW (YFBW) of the embryos on d 19.5 of incubation and of the chicks on day of hatch were determined. Eggs containing live embryos were injected in the amnion on d 18.5 of incubation using an automated multiple-egg injector. Solution injections delivered 1.2 mL of physiological saline (0.85%) alone or with a supplemental carbohydrate. The following supplemental carbohydrates were separately dissolved in saline at a concentration of 0.3 g/mL: glucose, fructose, sucrose, maltose, and dextrin. Temperature transponders were implanted in the air cells of embryonated and nonembryonated eggs after in ovo injection for the detection of IT at 6, 14, and 22 h after injection. The IT of embryonated eggs was significantly greater than that of nonembryonated eggs at all 3 times after the treatment period. Eggs that were injected with saline with or without supplemental carbohydrates experienced a reduction in IT when compared with control eggs whose shells were perforated without solution delivery, and the decrease in IT was associated with a delay in hatch time. Liver weight was negatively related to YSW and positively related to YFBW, and YSW was negatively related to YFBW. Although the saline and carbohydrate solution injections increased chick BW compared with noninjected controls, chick YFBW was decreased in the maltose- and sucrose-injected groups. In conclusion, the injection of 1.2 mL of saline with or without supplemental carbohydrates lowered embryonic metabolism, as reflected by a lower IT and a delay in time of hatch. However, effects of the different carbohydrate solutions on yolk absorption and tissue deposition in yolk-free embryos varied. These results suggest that lower volumes for solutions containing maltose, sucrose, or fructose should be considered for in ovo injection.
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Carbohidratos/administración & dosificación , Embrión de Pollo/efectos de los fármacos , Amnios/efectos de los fármacos , Animales , Regulación de la Temperatura Corporal/efectos de los fármacos , Embrión de Pollo/anatomía & histología , Embrión de Pollo/fisiología , Huevos , Inyecciones/veterinaria , Hígado/embriología , Tamaño de los Órganos , Soluciones , Saco Vitelino/embriologíaRESUMEN
The breeding of male layer chickens is currently considered to be highly uneconomical. In Germany alone, 40 to 50 million newly hatched male chickens were killed annually immediately after hatching. Therefore, it is necessary to find a method for sexing chickens early in the embryonic development, preferably before incubation. The genotypic sex of an egg can be determined using information found in the germinal disc, so knowledge of the exact position of the germinal disc is essential for further sexing, or for other actions such as the in ovo injection of agents. Previous studies have shown that the germinal disc is located somewhere on top of the yolk. However, no studies have yet been performed that investigate the influence of time spent in horizontal storage on the position of the germinal disc. Magnetic resonance imaging was chosen to determine this influence on the position of the germinal disc. It was found that eggs placed horizontally for long periods of time before scanning had significant changes in the positions of their germinal discs compared with those of eggs scanned minutes after positioning. The position of the germinal disc in eggs, minutes after horizontal positioning, deviated 14.7 ± 0.6 mm from the maximum vertical plane of the egg (zero position) in the z-direction; eggs scanned after 96 h of horizontal positioning showed a deviation of only 4.9 ± 1.6 mm. The x-axis also exhibited changes in the position of the germinal disc over time. Immediately after horizontal positioning, the eggs showed a deviation of 0.4 ± 0.4 mm in the x-direction, whereas the deviation after 96 h was 2.9 ± 0.5 mm. These results show that horizontal positioning of the egg hours before the measurement is necessary.
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Blastodisco/anatomía & histología , Embrión de Pollo/anatomía & histología , Animales , Blastodisco/química , Cruzamiento , Femenino , Imagen por Resonancia Magnética , Masculino , Análisis para Determinación del Sexo/métodos , Análisis para Determinación del Sexo/veterinaria , Factores de TiempoRESUMEN
We present a broadly applicable procedure for whole-mount imaging of antibody probes in embryonic tissues at microscopic resolutions based on combining a metal-based immunodetection scheme with x-ray microtomography (microCT). The method is generally accessible, relying on standard enzyme-conjugated secondary antibodies and other readily available reagents, and is demonstrated here with microCT visualizations of acetylated α-tubulin in the chick nervous system and of type II collagen in developing limbs. The tomographic images offer complete three-dimensional representations of molecular patterns obtained with immunostaining methods at the level of organ development, with added possibilities to quantify both spatial distributions and varying densities of gene products in situ. This imaging modality bridges a crucial gap in three-dimensional molecular imaging by combining the histological resolutions of confocal microscopy with a greater specimen size range than optical projection tomography, and thus enables a powerful new approach to long-standing issues of skeletogenic pattern formation in vertebrate limbs.
Asunto(s)
Extremidades/anatomía & histología , Extremidades/embriología , Imagenología Tridimensional/métodos , Imagen Molecular/métodos , Proteínas/metabolismo , Microtomografía por Rayos X/métodos , Animales , Tipificación del Cuerpo , Embrión de Pollo/anatomía & histología , Embrión de Pollo/metabolismo , Extremidades/fisiología , Organogénesis/fisiologíaRESUMEN
Neural crest cells give rise to a diverse range of structures during vertebrate development. These cells initially exist in the dorsal neuroepithelium and subsequently acquire the capacity to migrate. Although studies have documented the importance of adherens junctions in regulating neural crest cell migration, little attention has been paid to tight junctions during this process. We now identify the tight junction protein cingulin as a key regulator of neural crest migration. Cingulin knock-down increases the migratory neural crest cell domain, which is correlated with a disruption of the neural tube basal lamina. Overexpression of cingulin also augments neural crest cell migration and is associated with similar basal lamina changes and an expansion of the premigratory neural crest population. Cingulin overexpression causes aberrant ventrolateral neuroepithelial cell delamination, which is linked to laminin loss and a decrease in RhoA. Together, our results highlight a novel function for cingulin in the neural crest.
Asunto(s)
Movimiento Celular/fisiología , Proteínas de la Membrana/metabolismo , Proteínas de Microfilamentos/metabolismo , Morfogénesis/fisiología , Cresta Neural/citología , Cresta Neural/metabolismo , Uniones Estrechas/metabolismo , Animales , Membrana Basal/fisiología , Embrión de Pollo/anatomía & histología , Embrión de Pollo/fisiología , Hibridación in Situ , Proteínas de la Membrana/genética , Proteínas de Microfilamentos/genética , Cresta Neural/embriología , Tubo Neural/citología , Tubo Neural/metabolismo , Proteína de Unión al GTP rhoA/metabolismoRESUMEN
Bone morphogenetic protein (BMP) signals are essential for lens development. However, the temporal requirement of BMP activity during early events of lens development has remained elusive. To investigate this question, we have used gain- and loss-of-function analyses in chick explant and intact embryo assays. Here, we show that BMP activity is both required and sufficient to induce L-Maf expression, whereas the onset of δ-crystallin and initial elongation of primary lens fibre cells are BMP-independent. Moreover, before lens placode formation and L-Maf onset, but not after, prospective lens placodal cells can switch to an olfactory placodal fate in response to decreased BMP activity. In addition, L-Maf is sufficient to up-regulate δ-crystallin independent of BMP signals. Taken together, these results show that before L-Maf induction BMP activity is required for lens specification, whereas after L-Maf up-regulation, the early differentiation of primary lens fibre cells occurs independent of BMP signals.
Asunto(s)
Proteínas Morfogenéticas Óseas/metabolismo , Diferenciación Celular/fisiología , Cristalino/citología , Cristalino/embriología , Factores de Transcripción Maf/metabolismo , Animales , Proteínas Morfogenéticas Óseas/genética , Embrión de Pollo/anatomía & histología , Embrión de Pollo/fisiología , Proteínas del Ojo/genética , Proteínas del Ojo/metabolismo , Regulación del Desarrollo de la Expresión Génica , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Queratinas/genética , Queratinas/metabolismo , Factores de Transcripción Maf/genética , Factor de Transcripción PAX6 , Factores de Transcripción Paired Box/genética , Factores de Transcripción Paired Box/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Factores de Transcripción SOXB1/genética , Factores de Transcripción SOXB1/metabolismo , Transducción de Señal/fisiología , Proteínas Smad/genética , Proteínas Smad/metabolismo , delta-Cristalinas/genética , delta-Cristalinas/metabolismoRESUMEN
Many clinically relevant congenital malformations arise during mid to late embryonic stages. This period is challenging to image quantitatively in live embryos, necessitating the use of multiple specimens with increased experimental variability. Here we establish X-ray and blood-pool computed tomography (CT) contrast agent toxicity and teratogenesis thresholds for 3D Micro-CT imaging of live avian embryos. Day 4 chick embryos micro-injected with Visipaque™ (VP) developed for an additional 6 days without defect. X-ray radiation up to 798 mGy was nontoxic. Peak average contrast of 1,060 HU occurred within 1 hr of imaging at 50 µm resolution. VP-enhanced contrast persisted past 24 hr with delayed accumulation in the allantois. Regional volumes of VP-injected embryos were statistically identical to those of fixed embryos perfused with osmium tetroxide. We further quantified longitudinal volumetric morphogenesis of the allantois over 30 hr. These results demonstrate the safety and efficacy of contrast enhanced quantitative micro-CT imaging for live embryos.