Home About us Contact
|
Home About us Contact | ||
|
|
||
Pronephric Tubules (pronephric + tubule)
Selected AbstractsPatterning the embryonic kidney: BMP signaling mediates the differentiation of the pronephric tubules and duct in Xenopus laevisDEVELOPMENTAL DYNAMICS, Issue 1 2008Christina M. Bracken Abstract The Bone morphogenetic proteins (BMPs) mediate a wide range of diverse cellular behaviors throughout development. Previous studies implicated an important role for BMP signaling during the differentiation of the definitive mammalian kidney, the metanephros. In order to examine whether BMP signaling also plays an important role during the patterning of earlier renal systems, we examined the development of the earliest nephric system, the pronephros. Using the amphibian model system Xenopus laevis, in combination with reagents designed to inhibit BMP signaling during specific stages of nephric development, we revealed an evolutionarily conserved role for this signaling pathway during renal morphogenesis. Our results demonstrate that conditional BMP inhibition after specification of the pronephric anlagen is completed, but prior to the onset of morphogenesis and differentiation of renal tissues, results in the severe malformation of both the pronephric duct and tubules. Importantly, the effects of BMP signaling on the developing nephron during this developmental window are specific, only affecting the developing duct and tubules, but not the glomus. These data, combined with previous studies examining metanephric development in mice, provide further support that BMP functions to mediate morphogenesis of the specified renal field during vertebrate embryogenesis. Specifically, BMP signaling is required for the differentiation of two types of nephric structures, the pronephric tubules and duct. Developmental Dynamics 237:132,144, 2008. © 2007 Wiley-Liss, Inc. [source] Neuronal calcium sensor-1 gene ncs-1a is essential for semicircular canal formation in zebrafish inner earDEVELOPMENTAL NEUROBIOLOGY, Issue 3 2005Brian Blasiole Abstract We have analyzed the functional role of neuronal calcium sensor-1 (Ncs-1) in zebrafish development. We identified two orthologs of the mammalian NCS-1 gene. Full-length cDNAs encoding zebrafish Ncs-1a and Ncs-1b polypeptides were cloned and characterized. Whole-mount in situ hybridization revealed that ncs-1a mRNA was expressed beginning at early somitogenesis. As development progressed, ncs-1a mRNA was present throughout the embryo with expression detected in ventral hematopoietic mesoderm, pronephric tubules, CNS nuclei, and otic vesicle. By 4.5 days post fertilization (dpf), ncs-1a expression was detected primarily in the brain. Expression of ncs-1b mRNA was first detected at 36 hours post fertilization (hpf) and was restricted to the olfactory bulb. By 4.5 dpf, ncs-1b was expressed at low levels throughout the brain. Knockdown of ncs-1a mRNA translation with antisense morpholinos blocked formation of semicircular canals. These studies identify a novel function for ncs-1a in inner ear development and suggest that this calcium sensor plays an important role in vestibular function. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source] Origin and development of the pronephros in the chick embryoJOURNAL OF ANATOMY, Issue 6 2003Tamiko Hiruma Abstract The process by which the pronephros develops was morphologically examined in chick embryos from Hamburger,Hamilton stage (ST) 8+ to ST34. The intermediate mesoderm, from which the pronephros arises, was first seen as a faint ridge of undifferentiated mesoderm between the segmental plate and lateral plate at ST8+. It formed a cell cord at the level of the 6th to the presumptive 13th somites at ST9 to ST10. This cell cord then separated into dorsal and ventral parts, the former becoming the nephric duct and the latter the tubules by ST14. The primordia of the external glomeruli (PEGs) appeared at ST15 through some epithelial cells protruding in the nephrostome (the opening of the nephric tubule into the body cavity). PEGs formed gradually in the caudal direction until ST18, while the pronephric tubules and PEGs in cranial locations disappeared. At this stage, only a few PEGs remained at the level of the 13th and 14th somites and these developed from ST23 to ST29 to become ultrastructurally similar to the glomeruli of the functional kidney. From these observations in the avian pronephros, we infer that the pronephric duct and tubules both form from a cell cord in the intermediate mesoderm and at the same time, but later develop differently. [source] Immunolocalization of Na+, K+ -ATPase-rich cells in the gill and urinary system of Persian sturgeon, Acipenser persicus, fryAQUACULTURE RESEARCH, Issue 3 2009Saber Khodabandeh Abstract Localization of Na+, K+ -ATPase-rich cells in the gill and urinary system of Acipenser persicus fry was performed through immunofluorescence light microscopy using a mouse monoclonal antibody IgG,5 raised against the ,-subunit of chicken Na+, K+ -ATPase. Different types of epithelia were clearly identified in the gill epithelium: epithelia of branchial arch, interbranchial septum, filament and lamellar epithelium. The Na+, K+ -ATPase-rich cells were found in the epithelia of branchial arch, interbranchial septum, filament, interlamellar region and also in the lamellae. Histologically, the urinary system is divided into head kidney, trunk kidney and short caudal kidney. The head kidney is composed of the pronephric tubules and the haemopoietic tissues, while the trunk kidney is composed of a large number of glomeruli and convoluted nephrons. Each nephron consisted of a large glomerulus and tubules (neck, proximal, distal and collecting tubules) which connected to ureters. Posteriorly, ureters extended and joined together to form a small urinary bladder. In the urinary system, no specific fluorescence staining was observed in the glomerulus, neck segment and proximal tubules. The distal tubule cells and collecting tubule cells showed a strong immunostaining of Na+, K+ -ATPase. Epithelia of ureters and urinary bladder also showed several isolated immunofluorescent cells. Immunofluorescent cells were rich in Na+, K+ -ATPase enzyme which is very important for osmoregulation. [source] | ||||||||||