| plasma renin activity and blood corticosteroids in the australian lungfish neoceratodus forsteri. | plasma renin activity (pra) and blood aldosterone and deoxycorticosterone levels were measured in australian lungfish. plasma renin activity was depressed after intravenous infusions of iso-osmotic (0-6%) nacl but not after hypo-osmotic (0-3%) infusions. the presence of pra in this fish is consistent with prior reports of renal renin activity in other sarcopterygian fishes. the results of the infusion experiments suggest that a fall in plasma osmolality or electrolyte concentrations may oppose t ... | 1977 | 874409 |
| ultrastructure of the integumental melanophores of the australian lungfish, neoceratodus forsteri. | the integumental melanophores of australina lungfish, neoceratodus forsteri, were examined by light and electron microscopy and found to possess essentially the same structural characteristics observed in other vertebrates. the epidermal melanophores are located in the intermediate epidermis and possess round perikarya and slender dendrites extending into nearby intercellular spaces. the dermal melanophores are found immediately below the basement membrane as well as in the deeper dermis. these ... | 1975 | 1149085 |
| analysis of acth-related and clip-related peptides partially purified from the pituitary of the australian lungfish, neoceratodus forsteri. | acid extracts of individual lungfish pituitaries were fractionated by gel filtration on a sephadex g-75 column and aliquots of column fractions were screened with a heterologous acth(1-39) radioimmunoassay (ria). two major, incompletely separated, peaks of acth-related immunoreactivity were detected. these peaks of acth-related material were resolved by reverse-phase high-performance liquid chromatography and were designated peak a and peak b. peak a had a retention time more hydrophilic than sy ... | 1990 | 2162307 |
| binding of adrenergic ligands to liver plasma membrane preparations from the axolotl, ambystoma mexicanum; the toad, xenopus laevis; and the australian lungfish, neoceratodus forsteri. | the beta-adrenergic ligand iodocyanopindolol (icp) bound specifically to hepatic plasma membrane preparations from the axolotl, ambystoma mexicanum (bmax, 40 fmol/mg protein (p) at free concentration above 140 pm; kd, 42 pm); the toad, xenopus laevis (bmax, 200 fmol/mg p at 1 nm; kd, 300 pm); and the australian lungfish, neoceratodus forsteri (bmax, 100 fmol/mg p at 5 nm). for the lungfish, the scatchard plot was curved showing two classes of binding site with kd's of 20 and 500 pm. neither the ... | 1988 | 2847957 |
| the development of the intra-intestinal artery in the australian lungfish, neoceratodus forsteri. | the development of the intra-intestinal artery in the australian lungfish, neoceratodus forsteri was studied by dye injection. the right arterior wall of the midgut changes to become the valvular wall of the original part of the spiral valve owing to the shift of the foregut towards the posterior and the left ventral to the midgut. the anlage of the intra-intestinal artery appears in the blood vascular network on the valvular wall of the original part of the spiral valve; this network receives a ... | 1985 | 3913341 |
| hypocalcemic activities in the ultimobranchial bodies of lungfishes, neoceratodus forsteri and lepidosiren paradoxa and teleosts, fundulus heteroclitus and gadus morhua. | | 1971 | 5128307 |
| isolation and characterization of immunoglobulin-like proteins of the australian lungfish (neoceratodus forsteri). | | 1969 | 5387832 |
| neuropeptides in the australian lungfish neoceratodus forsteri: effects in vivo and presence in autonomic nerves. | the australian lungfish neoceratodus forsteri is one of the few extant species of a phylogenetically ancient group. immunohistochemistry showed the presence of galanin-, vasoactive intestinal polypeptide (vip)-, neurotensin-, substance p-, and calcitonin gene-related peptide (cgrp)-like immunoreactivities in nerve fibers in the heart, lung, and gut, with a coexistence of vip-, galanin-, and somatostatin-like immunoreactivity in the lung and galanin- and somatostatin-like immunoreactivity in the ... | 1994 | 7515591 |
| central projections of the nervus terminalis and the nervus praeopticus in the lungfish brain revealed by nitric oxide synthase. | lungfishes possess two cranial nerves that are associated with the olfactory system: the nervus terminalis enters the telencephalon with the olfactory nerve, and the nervus praeopticus enters the diencephalon at the level of the optic nerve. we investigated the central projections of the nervus terminalis and the nervus praeopticus in the australian lungfish (neoceratodus forsteri) and in the african lungfish (protopterus dolloi) by nadph-diaphorase histochemistry (nitric oxide synthase; nos) an ... | 1994 | 7531722 |
| identification of the molecular forms of and steroid hormone response to gonadotropin-releasing hormone in the australian lungfish, neoceratodus forsteri. | gonadotropin-releasing hormone (gnrh) peptides in the hypothalamus of the lungfish, neoceratodus forsteri, were investigated by reverse-phase hplc and ria with region-specific antisera. both chicken gnrh ii and mammalian gnrh were identified, the latter being present in greater concentration. the steroidogenic response to a single intracardiac injection of synthetic mammalian gnrh was investigated in early and late spring (beginning and end of spawning season) and in early autumn. in early sprin ... | 1994 | 7883146 |
| immunocytochemical localization and characterization of mammalian prolactin- and somatotropin-like material in the pituitary of the australian lungfish, neoceratodus forsteri. | the aim of the present study was to define at the light-microscopic level expression of prolactin and somatotropin material in the pituitary gland of the australian lungfish, neoceratodus forsteri, by use of polyclonal antibodies against ovine prolactin (oprl) and bovine somatotropin (bsth). substances immunologically related to mammalian oprl as well as bsth were detected in two morphologically different cell types in the distal lobe, corresponding to the acidophilic cells. the specificity of t ... | 1994 | 8187154 |
| karyotype and nuclear dna content of the australian lungfish, neoceratodus forsteri (ceratodidae: dipnoi). | the karyotype of the lungfish, neoceratodus forsteri, is described as 2n = 54, comprising 3 pairs of very large metacentrics, 1 pair of large submetacentrics, 13 pairs of smaller acrocentrics, and 10 pairs of microchromosomes. in addition to centromeric constitutive heterochromatin, c-bands were located on the arms of almost all of the macrochromosomes. the nuclear dna content of n. forsteri was confirmed as being high (98.6-111.9 pg/nucleus). | 1996 | 8697805 |
| are extant lungfish neotenic? | 1. the thyroid axis in developing lungfish is being explored to ascertain whether it shows similar deficiencies to those characteristic of neoteny in urodele amphibians. 2. at hatching, the pituitary of neoceratodus forsteri comprises a lumen surrounded by a single layer of epithelial cells lying immediately below the hypothalamus, but unconnected to it. over the first year of development, the number of pituitary cells increases and several cell types, including thyrotropes, can be recognized im ... | 1998 | 9750965 |
| immunocytochemical localization and characterization of mammalian thyrotropin-like material in the pituitary of the australian lungfish, neoceratodus forsteri. | the binding sites of polyclonal antisera raised against the beta-subunit of human thyroid-stimulating hormone (htshbeta), htsh, and ovine tsh (otsh) have been localized in the pituitary gland of the australian lungfish, neoceratodus forsteri, using light microscopy. reactivity toward anti-tsh antiserum was demonstrated in a slightly elongated and irregularly-shaped distinct cell type forming clusters in the dorso-central and ventral regions of the distal lobe. their granules react with alcian bl ... | 1998 | 9799468 |
| diversity "down under": monogeneans in the antipodes (australia) with a prediction of monogenean biodiversity worldwide. | there are approximately 25,000 species of fishes known in the world. the monogenea are believed to be among the most host-specific of parasites and if each species of fish is host to a different species of monogenean, there could be almost 25,000 monogenean species on earth. currently, i estimate that between 3000 and 4000 of these are described. australia has a rich marine fish fauna with approximately 3500 species of teleosts. if the same formula of one monogenean species per host fish species ... | 1998 | 9801912 |
| teleost-type angiotensin is present in australian lungfish, neoceratodus forsteri. | angiotensin i (ang i) was produced from the incubation of lungfish plasma with homologous kidney extracts. the purified peptide was found to have the sequence of h-asn-arg-val-tyr-val-his-pro-phe-thr-leu-oh, which is homologous for the first eight residues with all teleost angiotensins so far sequenced, although lungfish generally possess tetrapod-type hormones. the lungfish decapeptide (ang i) induced dose-dependent increases in arterial pressure in the rat. the lungfish octapeptide (ang ii) re ... | 1999 | 10208769 |
| homeobox genes in the australian lungfish, neoceratodus forsteri. | the aim of the present study was to determine whether the postulated gnathostome duplication from four to eight hox clusters occurred before or after the split between the actinopterygian and sarcopterygian fish by characterizing hox genes from the sarcopterygian lungfish, neoceratodus forsteri. since lungfish have extremely large genomes, we took the approach of extracting pure high molecular weight (mw) genomic dna to act as a template for polymerase chain reaction (pcr) of the conserved homeo ... | 1999 | 10440725 |
| ultrastructural and protein analysis of surfactant in the australian lungfish neoceratodus forsteri: evidence for conservation of composition for 300 million years. | the australian lungfish neoceratodus forsteri is the most primitive member of the lungfish family, with a surfactant lipid composition similar to the actinopterygiian fishes, which evolved 400 million years ago. we have analysed the proteins associated with surfactant isolated from lung lavage of this species, and used electron microscopy and immunohistochemistry to examine the surfactant structures and the subcellular localisation of these proteins. the epithelial lining of the gas-exchange reg ... | 1999 | 10460742 |
| purification and characterization of insulin from the australian lungfish, neoceratodus forsteri (dipnoi). | the australian lungfish neoceratodus forsteri, a facultative air breather, is considered to be the most primitive of the extant dipnoi and so occupies a uniquely important evolutionary position in the transition from fish to tetrapods. insulin was isolated from an extract of the pancreas of n. forsteri and its primary structure established as: a-chain, gly-ile-val-glu-gln-cys-cys-his-thr-pro(10)-cys-ser-leu-tyr-gln-leu-g lu-asn-tyr-cys(20)-asn-glu-thr-glu; b-chain, ala-ala-val-asn-gln-his-leu-cy ... | 1999 | 10525356 |
| true enamel covering in teeth of the australian lungfish neoceratodus forsteri. | lungfish are a unique order of sarcopterygian fish cleidographically positioned between tetrapods and fish. an uninterrupted 400-million-year-old fossil record has documented lungfish skeletal elements to remain virtually unchanged since the early devonian. in the current study we investigated the enamel layer of lungfish teeth in order to determine whether there was evidence for higher vertebrate "true" enamel in the australian lungfish. juvenile lungfish from the brisbane river were processed ... | 2000 | 10654067 |
| deiodinase type ii and tissue specific mrna alternative splicing in the australian lungfish, neoceratodus forsteri. | deiodinase type ii metabolises the prohormone t4 (thyroxine) into the biologically active hormone t3 (3,5,3'-triiodothyronine), at the cellular level in extrathyroidal target tissues. in juvenile lungfish, neoceratodus forsteri, a typical deiodinase type ii is present in most tissues. we have identified the full length of a 1.8 kb deiodinase type ii mrna in liver, and a truncated (1.3 kb) version in brain. both mrnas have two in frame uga codons, but only the liver form has a predicted secis str ... | 2003 | 12849964 |
| cloning of prodynorphin cdnas from the brain of australian and african lungfish: implications for the evolution of the prodynorphin gene. | in mammals the opioids met-enkephalin and leu-enkephalin are derived from a common precursor, proenkephalin, and as a result these neuropeptides are co-localized in enkephalinergic neurons. the mammalian scheme for enkephalinergic networks is not universal for all classes of sarcopterygian vertebrates. in an earlier study, distinct met- and leu-enkephalin-positive neurons were detected in the central nervous system (cns) of the african lungfish, protopterus annectens. more recently, characteriza ... | 2004 | 15153752 |
| nfcr1, the first non-ltr retrotransposon characterized in the australian lungfish genome, neoceratodus forsteri, shows similarities to cr1-like elements. | the genomes of lungfish, together with those of some urodele amphibians, are the largest of all vertebrate genomes. it has been assumed that the bulk of the dna making up these large genomes has been derived from repeat elements, like the noncoding dna of those genomes that have been sequenced (e.g., human). in an attempt to characterize repeat sequences in the lungfish genome, we have isolated, by restriction enzyme digestion of genomic dna, sequences of a repeat element in neoceratodus forster ... | 2005 | 15593278 |
| complete mitochondrial genome sequences of the south american and the australian lungfish: testing of the phylogenetic performance of mitochondrial data sets for phylogenetic problems in tetrapod relationships. | we determined the complete nucleotide sequences (16403 and 16572 base pairs, respectively) of the mitochondrial genomes of the south american lungfish, lepidosiren paradoxa, and the australian lungfish, neoceratodus forsteri (sarcopterygii, dipnoi). the mitochondrial dna sequences were established in an effort to resolve the debated evolutionary positions of the lungfish and the coelacanth relative to land vertebrates. previous molecular phylogenetic studies based on complete mtdna sequences, in ... | 2004 | 15599515 |
| the corneal epithelial surface in the eyes of vertebrates: environmental and evolutionary influences on structure and function. | the smooth optical surface of the cornea is maintained by a tear film, which adheres to a variety of microprojections. these microprojections increase the cell surface area and are thought to improve the movement of oxygen, nutrients, and metabolic products across the outer cell membranes. however, little is known of these structural adaptations in vertebrates inhabiting different environments. this field emission scanning electron microscopic study examined the cell density and surface structur ... | 2006 | 16323209 |
| lungfish albumin is more similar to tetrapod than to teleost albumins: purification and characterisation of albumin from the australian lungfish, neoceratodus forsteri. | lobe-finned fish, particularly lungfish, are thought of as the closest extant relatives to tetrapods. albumin, the major vertebrate plasma protein, has been well studied in tetrapods, but there exists no comparative study of the presence and characteristics of albumin in lobe-finned fish versus other vertebrates. there is a controversy over the presence of albumin in fish, although it is present in salmonids and lamprey. the presence of albumin in lungfish has also recently been documented. we i ... | 2007 | 17409005 |
| high resolution transmission electron microscopy of developing enamel in the australian lungfish, neoceratodus forsteri (osteichthyes: dipnoi). | the permanent tooth plates of the australian lungfish, neoceratodus forsteri, are covered by enamel that develops initially in a similar manner to that of other vertebrates. as the enamel layer matures, it acquires several unusual characteristics. it has radially oriented protoprismatic structures with the long axes of the protoprisms perpendicular to the enamel surface. protoprisms can be defined as aggregations of hydroxyapatite crystals that lack the highly ordered arrangement of the rods of ... | 2007 | 17888476 |
| anatomy and cytology of the thymus in juvenile australian lungfish, neoceratodus forsteri. | the anatomy, histology and ultrastructure of the thymus of a dipnoan, the australian lungfish, neoceratodus forsteri, was studied by light and transmission electron microscopy. the thymic tissue showed clear demarcation into a cortex and medulla with ample vascularization. large cells including foamy and giant multinucleated cells with periodic acid schiff/alcian blue positive staining properties were localized mainly in the medulla. the major cellular components were epithelial cells and lympho ... | 2007 | 17944863 |
| visual pigments in a living fossil, the australian lungfish neoceratodus forsteri. | one of the greatest challenges facing the early land vertebrates was the need to effectively interpret a terrestrial environment. interpretation was based on ocular adaptations evolved for an aquatic environment millions of years earlier. the australian lungfish neoceratodus forsteri is thought to be the closest living relative to the first terrestrial vertebrate, and yet nothing is known about the visual pigments present in lungfish or the early tetrapods. | 2007 | 17961206 |
| vascular distribution of nitric oxide synthase and vasodilation in the australian lungfish, neoceratodus forsteri. | the presence of nitric oxide synthase (nos) and role of nitric oxide (no) in vascular regulation was investigated in the australian lungfish, neoceratodus forsteri. no evidence was found for nos in the endothelium of large and small blood vessels following processing for nadph-diaphorase histochemistry. however, both nadph-diaphorase histochemistry and neural nos immunohistochemistry demonstrated a sparse network of nitrergic nerves in the dorsal aorta, hepatic artery, and branchial arteries, bu ... | 2008 | 18692149 |
| cytoskeletal proteins in thymic epithelial cells of the australian lungfish neoceratodus forsteri. | the vertebrate thymus consists of distinctive subpopulations of epithelial cells that contain a diverse repertoire of cytoskeletal proteins. in this study of the thymus in the australian lungfish, neoceratodus forsteri, immunohistochemistry was used to distinguish the cytoskeletal proteins present in each class of thymic epithelial cell. a panel of antibodies (abs), each specific for a different cytoskeletal polypeptide (keratins, vimentin, desmin, actin and tubulins), was used on paraffin and u ... | 2009 | 19166477 |
| evolution of developmental pattern for vertebrate dentitions: an oro-pharyngeal specific mechanism. | classically the oral dentition with teeth regulated into a successional iterative order was thought to have evolved from the superficial skin denticles migrating into the mouth at the stage when jaws evolved. the canonical view is that the initiation of a pattern order for teeth at the mouth margin required development of a sub-epithelial, permanent dental lamina. this provided regulated tooth production in advance of functional need, as exemplified by the chondrichthyes. it had been assumed tha ... | 2010 | 21328527 |
| insulin-, glucagon- and somatostatin-like immunoreactivity in the endocrine pancreas of the lungfish, neoceratodus forsteri. | the endocrine pancreas of the australian lungfish, neoceratodus forsteri, was investigated immunocytochemically for the presence of polypeptide hormone-producing cells. three cell types were identified, namely insulin-, glucagon-, and somatostatin-immunoreactive elements. the insulin cells are confined solely to the center of the islets. glucagon and somatostatin cells are distributed peripherally around the central mass of the insulin cells. isolated cells or clusters of glucagon and somatostat ... | 2007 | 2882854 |
| the australian lungfish (neoceratodus forsteri) - fish or amphibian pattern of muscle development? | the australian lungfish neoceratodus forsteri (dipnoi-sarcoterygians) is a likely candidate for the extant sister group of tetrapoda. transmission electron and light microscopy analysis revealed that the arrangement of somite cells of the lungfish resembles the structure of the urodelan somite. on the other hand, the pattern of early muscle formation in n. forsteri is similar to that found in the siberian sturgeon (acipenser baeri). during the early stages of myogenesis of n. forsteri, somite-de ... | 2008 | 18311718 |
| architecture of the integument in lower teleostomes: functional morphology and evolutionary implications. | a bony ganoid squamation is the plesiomorphic type in actinopterygians. during evolution, it was replaced by weak and more flexible elasmoid scales. we provide a comparative description of the integument of "ganoid" fishes and "nonganoid" fishes that considers all dermal components of mechanical significance (stratum compactum, morphology of ganoid scales, and their regional differences) in order to develop a functional understanding of the ganoid integument as a whole. data were obtained for th ... | 2002 | 12125067 |
| evolutionary history of the enolase gene family. | the enzyme enolase [ec 4.2.1.11] is found in all organisms, with vertebrates exhibiting tissue-specific isozymes encoded by three genes: alpha (alpha), beta (beta), and gamma (gamma) enolase. limited taxonomic sampling of enolase has obscured the timing of gene duplication events. to help clarify the evolutionary history of the gene family, cdnas were sequenced from six taxa representing major lineages of vertebrates: chiloscyllium punctatum (shark), amia calva (bowfin), salmo trutta (trout), la ... | 2000 | 11163970 |
| the development of the vasculature of the pelvic fin in the australian lungfish, neoceratodus forsteri. | the development of the vasculature of the pelvic fin in the australian lungfish, neoceratodus forsteri, was studied by the dye-injection method. the primitive iliac artery of the primitive iliocecal artery which originates in the dorsal aorta drains into the posterior cardinal vein. as development proceeds, the primitive iliac artery penetrates the fin anlage, and finally becomes the pelvic fin artery. the chief venous channel in the fin anlage draining into the posterior cardinal vein is the pe ... | 1988 | 3245040 |
| development of the vasculature of the pectoral fin in the australian lungfish, neoceratodus forsteri. | the development of the vasculature of the pectoral fin in the australian lungfish, neoceratodus forsteri, was studied by the dye-injection method. only a single primitive subclavian artery appears from the dorsal aorta for the fin anlage, and it passes laterally through the postaxial region of the structure. the venous channel draining into the posterior cardinal vein is located in the preaxial region medially. as development proceeds, the arteriovenous arrangement in the pectoral fin anlage cha ... | 1988 | 2456688 |
| use of electroreception during foraging by the australian lungfish. | a diverse range of animals, including elasmobranchs and nonteleost fish, use passive electroreception to locate hidden prey. the australian lungfish, neoceratodus forsteri (krefft 1870), has ampullary organs analogous in form to the electroreceptors of other nonteleost fish. afferents from these ampullae project to regions in the brain that are known to process electrosensory information in other species, suggesting that n. forsteri possesses an electric sense that may be used during prey locati ... | 1999 | 10564606 |
| regionalization of axial skeleton in the lungfish neoceratodus forsteri (dipnoi). | differentiation of the axial skeleton into distinct regions, once thought to be characteristic of the tetrapoda, also occurs in the actinopterygian danio rerio. in these taxa, the boundary between the cervical-thoracic regions correlates with hoxc6 expression and morphological features such as position of the pectoral fin and associated nerves, and the absence of ribs. in the lungfish neoceratodus, a member of the extant sister taxon to the tetrapoda, the first vertebral element to chondrify is ... | 2005 | 15880607 |
| purification, characterization, and biological activity of a substance p-related peptide from the gut of the australian lungfish, neoceratodus forsteri. | a peptide with mammalian substance p (sp)-like immunoreactivity was isolated from an extract of the spiral intestine of the australian lungfish, neoceratodus forsteri. the primary structure of this peptide was established as lys-pro-arg-pro-asp-glu-phe-tyr-gly-leu-met . nh2, showing 64% identity with mammalian sp. in isolated preparations of lungfish foregut circular muscle, lungfish sp produced a slow, long-lasting tonic contraction, with a pd2 value of 8.19. lungfish midgut circular muscle pre ... | 2002 | 11825039 |