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PubMed1991

Ultrastructural characteristics of renal corpuscle evolution in vertebrates.

Peculiarities of renal corpuscle's structural organization of a number of animals representing various classes of vertebrates have been studied on submicroscopic level at the stages of excretory organs formation: pronephros, mesonephros and metanephros. The fact has been established that side by side with the common structure there have been specific peculiarities due to the level of evolutional development and character of habitat.

Animals↗
PubMed1988

Granulopoiesis in tadpoles of Rana esculenta. Survey of the organs involved.

The topography and nature of granulopoietic tissues appearing during the larval period of Rana esculenta have been investigated using light and electron microscopy. The formation of eosinophils and heterophils occurred in the interstices of the pronephros and opisthonephros, in the mesenchymal sheath surrounding the pronephric duct, as well as in the mesentery and mesenchymal coat of the bile duct and hepatic ducts. Developing basophils were very rare, being detectable only in the stroma of the trunk kidneys. The pronephric interstices additionally contained differentiating lymphocytes, the opisthonephric interstices differentiating lymphocytes and erythrocytes. In contrast, the mesenchymal sheath of the pronephric duct as well as the mesentery and the mesenchymatous coat of the bile duct and hepatic ducts were solely granulopoietic.

Animals↗
PubMed1974

The normal embryologic development of the kidney: a basis for understanding structural abnormalities.

The embryologic development of the metanephric kidney is a regulated and sequential growth process. The induction of the early precursors of the metanephric kidney (pronephros and mesonephric) are essential first steps for the later appearance of the metanephric kidney. The pathogenesis of cystic disease can now be reexamined in light of these unique but carefully programmed growth processes with the expectation that the specific nature of the several growth disorders responsible can be more clearly defined.

Female↗
PubMed1979

[Ectopic ureter ending in the seminal vesicle in adults. Apropos of a case and review of the literature].

The authors report a 38 years old patient in whom an intravenous pyelogram was performed for moderate arterial hypertension. This showed a large filling defect in the right lower part of the bladder without renal function on that side. Endoscopic separation of the jet coming from the right half of the trigone showed a liquid containing numerous spermatozoa. A cystogram opacified by reflux a cavity in the genital system via this, the right ureter. With the diagnosis of ectopic ureter ending in the genital system, a nephro-ureterectomy demonstrated the attachment of the ureter into a pouch which communicated with the bladder and the seminal vesicle. A view of the normal embryology insists on the fact that contrary to the classic view, the pronephros disappears entirely and that the metanephros is at the origin of the Woffian canal which opens on the posterior wall of the urogenital sinus at the 28th day when the ureter springs from a ureteral bud. Since 1960 this would be the 34th case in the literature, seminal ectopia (24%) coming after ectopia in the prostatic urethra (54%). Epididymitis is a frequent presenting symptom (44%). The workup shows: absence of renal function (100%), raising of the ipsilateral trigone by a cystic swelling (76%), absence of the meatus on that side on endoscopy, presence of an ipsilateral mass above the prostate on rectal examination (30%). The diagnosis is confirmed by vasography where the ureter is opacified by the seminal vesicle or by systography after endoscopic incision of the mass. Excision of the seminal vesicle was done in conjunction with total nephroureterectomy in 17% of cases.

Adult↗
PubMed1979

The haemocytology and histology of the haemopoietic organs of South African fresh water fish. I. The haemopoietic organs of Clarias gariepinus and Sarotherodon mossambicus.

The haemopoietic organs of the catfish, Clarias gariepinus, and the Mozambique bream, Sarotherodon mossambicus, were studied. In both species the primary haemopoietic organs are the pronephros, the mesonephros and the spleen. The peritoneum and, particularly in catfish, the omentum are of secondary importance in haemopoiesis.

Animals↗
PubMed1977

[Cell surface immunoglobulin of carp lymphocytes (Cyprinus carpio L.)].

Molecular size and polypeptide chain composition of cell membrane immunoglobulin (mIg) on lymphocytes of carp were studied using lactopreoxidase-catalysed surface radioiodination and SDS-polyacrylamide gel electrophoresis. Carp lymphocytes prepared from pronephros, blood and thymus carry mIgM in relatively high quantity. That means about 5-10% of the radiolabelled macromolecular cell surface material precipitates as IgM. Cell surface IgM on carp lymphocytes is present as monomeric IgM (m.w. 220000-260000) and HL subunit (m.w. 110000). There are differences among molecular weights of mIg monomers of pronephric lymphocytes (m.w. 220000) and thymocytes (m.w. 260000), whereas blood lymphocytes show both components. Following reduction and alkylation H and L chains were observed. Additional thymocytic mIg possesses two unidentified components with m.w. 35000-40000 and 110000.

Animals↗
PubMed1982

Localization of immune complexes and heat-aggregated immunoglobulin in the carp Cyprinus carpio L.

In carp Cyprinus carpio L. preimmunized with a protein antigen, human gamma globulin (HGG), rapid localization of antigen occurred in the splenic ellipsoids within 1 day of a secondary immunization given 8 weeks later. Furthermore, after injection of immune complexes or heat-aggregated HGG, antigen was trapped more quickly in the pronephros than when antigen was injected alone. These results support the conclusion that in fish, as in homoiotherms, this form of antigen trapping is antibody-dependent.

Animals↗
PubMed1983

Evidence for specific feedback signals underlying pattern control during vertebrate embryogenesis.

Experiments are described in which sectors including dorsolateral mesoderm from early-neurula-stage amphibian embryos are grafted to the mid-ventral region of gastrula-stage hosts. The grafted tissue pursues an autonomous developmental sequence, though integrated into the host mesodermal mantle, so that such embryos develop a ventral strip of ectopic somite tissue, occasionally with a pronephric formation at one side. When the proportions in which mesodermal tissue has been assigned to the four basic territories of the host's mediolateral pattern are assayed, a significant deficit in somite is characteristically found, though the phenomenon is variable in magnitude. It seems that the size of the host's pronephric territory may be diminished in a similar way, if an earlier differentiating ectopic pronephros is already joined to the system. These phenomena are discussed in relation to theories of biological pattern formation.

Ambystoma mexicanum↗
PubMed1980

[Development of hematopoietic tissue in Rana temporaria L].

Embryogenesis of the hemopoietic tissue was histologically studied in Rana temporaria at successive developmental stages, beginning from neurula and up to the end of metamorphosis. Primary foci of hemopoiesis (yolk sac, pronephros, hepatic diverticulum) were also studied radioautographically. Histological description of the hemopoietic tissue in R. temporaria is presented according to common stages of development in the species investigated. The data concerning the early and, in fact, simultaneous appearance of primary blood cells (PBC) in embryonic foci, as well as the results of the radioautographic investigation on the dynamics of PBC proliferation demonstrate that there possibly exist some local sources of hemopoiesis in embryonic hemopoietic organs.

Animals↗
PubMed1994

Comparative analysis of Engrailed-1 and Wnt-1 expression in the developing central nervous system of Xenopus laevis.

Expression of the Engrailed-1 (XEn-1) gene was studied in Xenopus embryogenesis by Northern blot analysis and whole-mount in situ hybridization. One transcript of 2.2 kb was detected from stage 17 (midneurula) onwards, until stage 47 (swimming tadpole). The expression pattern of the XEn-1 gene as revealed by in situ hybridization can be divided in three regions. The first domain of transient expression appears at the midneurula stage (st. 17) in the anterior part of the neural fold, forming a complete ring of positive cells at the mid/hindbrain border after neural tube closure. A second region of transient expression is detected as groups of ventro-lateral cells in the spinal cord and the hindbrain from late-neurula till tadpole stages. A third area of transient expression of XEn-1 is formed by the anterior part of the developing pronephros. Comparison of XEn-1 expression at the mid/hindbrain border with that of the Xenopus wnt-1 and engrailed-2 genes reveals that XEn-1 and Xwnt-1, in contrast to XEn-2, are both detected in a narrow stripe of positive cells in this region. Analysis in exogastrulated embryos reveals that expression of XEn-1 and Xwnt-1, but not XEn-2, is induced by planar signaling in the presumptive midbrain. Of the three genes only XEn-1 is expressed in the floorplate at the mid/hindbrain border, while Xwnt-1 is expressed in adjacent cells in the neural ectoderm. The results suggest that in vertebrates at the interface between cells in the floorplate and in the paraxial neuroectoderm, at the limited region of the mid/hindbrain border, En-1 interacts with wnt-1 in a signaling pathway analogous to the engrailed/wingless signaling in the parasegments of the Drosophila embryo.

Amino Acid Sequence↗
PubMed1994

Response of Ig-positive cells to Goussia carpelli (Protozoa: Apicomplexa) infections in carp (Cyprinus carpio L.).

The kinetics of Ig-positive cell populations in carp tissues was followed during an infection with the gut dwelling coccidian Goussia carpelli Léger et Stankovich, 1921. In cell suspensions of the anterior and posterior sections of the intestine, the proportion of Ig-positive cells increased with the development of the coccidia and peaked during oocyst formation at day 15 post exposure. These results suggest a reaction of the local mucosal immune system. In cell suspensions of pronephros the proportion of Ig-positive cells increased as well, indicating that a systemic immune response was also induced against this intestinal coccidian parasite of carp.

Animals↗
PubMedDate not supplied

[Determination of some hematological aspects of Oncorhynchus mykiss (Salmonidae), in Cundinamarca, Columbia].

Thirty-five normal, adult specimens of the rainbow trout Oncorhynchus mykiss (Richardson, 1836) cultured in the Neusa Fishculture Station (73 degrees 38'28" W; 5 degrees 8'30" N) were studied to establish normal blood values; the hematopoietic tissues (pronefros, spleen and thymus), and other organs such as the stomach were also structurally studied. The rainbow trout collected in the second half of 1990 and the beginning of the first half of 1991 had 1,415,000 erythrocytes and 22,000 leukocytes per mm3 of blood. Their hemoglobin concentration was 6.99 g/100ml. They had three types of circulating leukocytes: lymphorytes 65%, polimorphonuclears 24% and monocytes 11%. The pronephros is the major hematopoietic organ in the rainbow trout. It produces mainly the polimorphonuclears; the spleen and the thymus are linfopoietics. The study of the hemocytometric values in the peripheral blood frotis and the structure of the hematopoietic organs of the rainbow trout is very useful, accessible and inexpensive. It produces data which yield information about physiological and pathological conditions.

Animals↗
PubMed1996

Regulation and function of the tissue-specific transcription factor HNF1 alpha (LFB1) during Xenopus development.

We review the data available on the structure, developmental appearance and embryonic regulation of the tissue-specific transcription factor HNF1 alpha (LFB1) in Xenopus. The expression of the HNF1 alpha gene starts early in embryogenesis shortly after mid-blastula transition and the protein accumulates in the region of the embryo where liver, pronephros and gut--tissues that contain HNF1 alpha in the adult--are developing. The cofactor DCoH, known to stabilize dimer formation of HNF1 alpha, is present as a maternal factor in the egg and has a partially distinct tissue distribution compared to HNF1 alpha. This implies that DCoH does not only modulate HNF1 alpha dimerization but may also cooperate with other transcription factors. By injecting HNF1 alpha promoter CAT constructs into fertilized Xenopus eggs we obtained activation of the injected gene restricted to the region of the developing larvae expressing endogenous HNF1 alpha. Deletion analysis allowed to define the OZ-element that is essential for embryonic activation. This element also occurs in other promoters activated at mid-blastula transition in the embryo and interacts with the maternal factor OZ-1. As the HNF1 alpha promoter also contains functional binding sites for HNF4 and HNF1, we postulate that all of these transcription factors contribute to the cascade leading to proper embryonic activation of the HNF1 alpha gene.

Animals↗
PubMed1996

The LIM homeodomain protein Lim-1 is widely expressed in neural, neural crest and mesoderm derivatives in vertebrate development.

Polyclonal antibodies to Xlim-1 homeodomain protein of Xenopus laevis were used to study the developmental expression pattern of this protein in Xenopus, rat and mouse. Western blotting of embryo extracts injected with different Xlim-1 constructs confirmed the specificity of the antibody. Beginning at the gastrula stage, Xlim-1 protein was detected in three cell lineages: (i) notochord, (ii) pronephros and (iii) certain regions of the central nervous system, in agreement with earlier studies of the expression of Xlim-1 RNA (Taira et al., Development 120: 1525-1536, 1994a). In addition, several new locations of Xlim-1 expression were found, including the olfactory organ, retina, otic vesicle, dorsal root ganglia and adrenal gland. Similar expression patterns were seen for the Lim-1 protein in frog and rodent tissues. These observations implicate the Xlim-1 gene in the specification of multiple cell lineages, particularly within the nervous system, and emphasize the conserved nature of the role of this gene in different vertebrate animals.

Animals↗
PubMed1997

Ets-1 and Ets-2 proto-oncogenes exhibit differential and restricted expression patterns during Xenopus laevis oogenesis and embryogenesis.

Xenopus XI-ets-1 and XI-ets-2 are maternally expressed. From late oogenesis to early embryogenesis their transcripts are localized to the animal pole and the intermediate zone, suggesting a function in the differentiation of animal blastomeres and future mesoderm. Their presence at the level of germ plasm suggests also a role in the differentiation of the germinal lineage. Both zygotic genes are expressed ubiquitously beginning at MBT, and then restricted to a circumblastoporal collar. In neurula and tailbud stages, ets-1 and ets-2 transcripts are detected in neural crest cells and their derivatives. Specific transcription can also be observed for ets-1 in the hemangioblastic precursors, in endothelial cells of the forming heart and blood vessels. Ets-2 is itself specifically expressed in the putative pronephros and in the forming pronephric tubules and extending pronephric duct. Like another member of the ets-gene family (XI-fli), both genes are transcribed in regions of the embryo undergoing important morphogenetic modifications, especially in migrating cells and/or along their migration pathways. We postulate that these genes orchestrate modifications of cellular adhesion. Changes in the expression of cadherins and integrins repertories would be consistent with such a role and could account for the phenotypes we reported earlier for XI-fli overexpression. Such a role would be critical for tumor cell dissemination, in addition to the one already ascribed to ets-1 in the expression of proteases specific for the extracellular matrix.

Animals↗
PubMed2026

Swimming Upstream to Understand Congenital Anomalies of the Kidney and Urinary Tract: Zebrafish Models for Developmental Biology, Disease Mechanisms, and Functional Interpretation of Genetic Variation.

Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of pediatric chronic kidney disease (CKD) and comprise a heterogeneous group of developmental disorders with a substantial genetic contribution. Advances in next-generation sequencing have facilitated the identification of numerous candidate genes and rare variants associated with CAKUT. However, establishing causality and defining the biological functions of implicated genes remain major challenges. Functional validation is therefore essential to bridge the gap between gene discovery and mechanistic understanding, enabling the interpretation of genetic variation within the context of kidney development and disease. The zebrafish (Danio rerio) has emerged as a powerful in vivo model for studying renal development and interrogating the function of CAKUT-associated genes. Its utility stems from a high degree of genetic and developmental conservation with humans, conserved nephrogenic pathways, optical transparency during embryogenesis, and the relative ease of genetic manipulation. In this review, we provide an overview of zebrafish kidney development within the broader context of vertebrate nephrogenesis, highlighting the key genetic programs governing intermediate mesoderm specification, nephron segmentation, and pronephric morphogenesis. We then systematically examine CAKUT-associated genes that have been modeled in zebrafish, focusing on studies that have linked genetic perturbations to renal development and structural phenotypes. Finally, we discuss the strengths and limitations of zebrafish models for functional genomics and variant interpretation and consider their emerging role in bridging genetic discovery with mechanistic insights into CAKUT pathogenesis.

Animals↗