| bichir hoxa cluster sequence reveals surprising trends in ray-finned fish genomic evolution. | the study of hox clusters and genes provides insights into the evolution of genomic regulation of development. derived ray-finned fishes (actinopterygii, teleostei) such as zebrafish and pufferfish possess duplicated hox clusters that have undergone considerable sequence evolution. whether these changes are associated with the duplication(s) that produced extra hox clusters is unresolved because comparison with basal lineages is unavailable. we sequenced and analyzed the hoxa cluster of the bich ... | 2004 | 14707166 |
| a new gyrodactylid (monogenea) genus on gray bichir, polypterus senegalus (polypteridae) from senegal (west africa). | diplogyrodactylus martini n. g. et sp., a viviparous monogenean, is described from the gills of gray bichir polypterus senegalus cuvier, 1829, in senegal. this new genus can be readily distinguished from the other described viviparous genera based on the morphology of the attachment apparatus. the haptor is equipped with a pair of centrally positioned hamuli, a simple ventral bar without membrane and 8 pairs of marginal hooks of 2 types, 5 pairs of hooks with well-defined large falculate sickles ... | 2009 | 19642801 |
| histochemical properties of sulfated glycoconjugates in developing enameloid matrix of the fish polypterus senegalus. | i investigated the ultrastructural localization and histochemical properties of sulfated glycoconjugates in developing enameloid matrix of the fish polypterus senegalus, by use of the high iron diamine thiocarbohydrazide silver proteinate (hid-tch-sp) staining and enzymatic digestion methods. hid-tch-sp stain deposits were localized in the dental basal lamina and in the whole thickness of developing enameloid matrix, particularly closely associated with enameloid collagen fibrils. most hid-tch-s ... | 1989 | 2470701 |
| fine structural and immunohistochemical detection of collar enamel in the teeth of polypterus senegalus, an actinopterygian fish. | this is the first detailed report about the collar enamel of the teeth of polypterus senegalus. we have examined the fine structure of the collar enamel and enamel organ of polypterus during amelogenesis by light and transmission electron microscopy. an immunohistochemical analysis with an antibody against bovine amelogenin, an antiserum against porcine amelogenin and region-specific antibodies or antiserum against the c-terminus, middle region and n-terminus of porcine amelogenin has also been ... | 2012 | 22287040 |
| natural flexible dermal armor. | fish, reptiles, and mammals can possess flexible dermal armor for protection. here we seek to find the means by which nature derives its protection by examining the scales from several fish (atractosteus spatula, arapaima gigas, polypterus senegalus, morone saxatilis, cyprinius carpio), and osteoderms from armadillos, alligators, and leatherback turtles. dermal armor has clearly been developed by convergent evolution in these different species. in general, it has a hierarchical structure with co ... | 2013 | 23161399 |
| finite element modeling of multilayered structures of fish scales. | the interlinked fish scales of atractosteus spatula (alligator gar) and polypterus senegalus (gray and albino bichir) are effective multilayered armor systems for protecting fish from threats such as aggressive conspecific interactions or predation. both types of fish scales have multi-layered structures with a harder and stiffer outer layer, and softer and more compliant inner layers. however, there are differences in relative layer thickness, property mismatch between layers, the property grad ... | 2014 | 25300062 |
| unusual intraindividual variation of the nuclear 18s rrna gene is widespread within the acipenseridae. | significant intraindividual variation in the sequence of the 18s rrna gene is unusual in animal genomes. in a previous study, multiple 18s rrna gene sequences were observed within individuals of eight species of sturgeon from north america but not in the north american paddlefish, polyodon spathula, in two species of polypterus (polypterus delhezi and polypterus senegalus), in other primitive fishes (erpetoichthys calabaricus, lepisosteus osseus, amia calva) or in a lungfish (protopterus sp.). t ... | 2008 | 16714428 |
| [radioautographic analysis of retinofugal projections in the primitive bony fish polypterus senegalus c]. | retinofugal pathways of polypterus senegalus c. have been examined by means of the radioautographic method. contralaterally the retina projects to the hypothalamus, thalamus, pretectum and tectum. an important ipsilateral component has been observed. no retinal projection to the mesencephalic tegmentum has been identified. comparing the primary optic system of polypterus with that of other body fish, indicates that this species possesses a combination of characteristics which are both actinopter ... | 2001 | 95000 |
| Acquisition of glial cells missing 2 enhancers contributes to a diversity of ionocytes in zebrafish. | Glial cells missing 2 (gcm2) encoding a GCM-motif transcription factor is expressed in the parathyroid in amniotes. In contrast, gcm2 is expressed in pharyngeal pouches (a homologous site of the parathyroid), gills, and H(+)-ATPase-rich cells (HRCs), a subset of ionocytes on the skin surface of the teleost fish zebrafish. Ionocytes are specialized cells that are involved in osmotic homeostasis in aquatic vertebrates. Here, we showed that gcm2 is essential for the development of HRCs and Na(+)-Cl ... | 2011 | 21858216 |
| hox clusters of the bichir (actinopterygii, polypterus senegalus) highlight unique patterns of sequence evolution in gnathostome phylogeny. | teleost fishes have extra hox gene clusters owing to shared or lineage-specific genome duplication events in rayfinned fish (actinopterygian) phylogeny. hence, extrapolating between genome function of teleosts and human or even between different fish species is difficult. we have sequenced and analyzed hox gene clusters of the senegal bichir (polypterus senegalus), an extant representative of the most basal actinopterygian lineage. bichir possesses four hox gene clusters (a, b, c, d); phylogenet ... | 2011 | 21688387 |
| materials design principles of ancient fish armour. | knowledge of the structure-property-function relationships of dermal scales of armoured fish could enable pathways to improved bioinspired human body armour, and may provide clues to the evolutionary origins of mineralized tissues. here, we present a multiscale experimental and computational approach that reveals the materials design principles present within individual ganoid scales from the 'living fossil' polypterus senegalus. this fish belongs to the ancient family polypteridae, which first ... | 2008 | 18660814 |
| immunocytochemical study of calretinin and calbindin d-28k expression in the retina of three cartilaginous fishes and a cladistian (polypterus). | the distribution of two calcium-binding proteins, calbindin d-28k (cb) and calretinin (cr) was studied in the retina of a cladistian, polypterus senegalus, and three cartilaginous fishes (scyliorhinus canicula, raja undulata and torpedo marmorata). western blot analysis of brain extracts revealed the lack of cross-reactivity of the used antibodies. in polypterus, cb and cr immunoreactivities were observed in some amacrine and ganglion cells, but scarce cells showed cr/cb colocalization. furtherm ... | 2008 | 18331901 |
| divergence of conserved non-coding sequences: rate estimates and relative rate tests. | in many eukaryotic genomes only a small fraction of the dna codes for proteins, but the non-protein coding dna harbors important genetic elements directing the development and the physiology of the organisms, like promoters, enhancers, insulators, and micro-rna genes. the molecular evolution of these genetic elements is difficult to study because their functional significance is hard to deduce from sequence information alone. here we propose an approach to the study of the rate of evolution of f ... | 2004 | 15282332 |
| characterizing a proopiomelanocortin cdna cloned from the brain of the bichir, polypterus senegalus: evaluating phylogenetic relationships among ray-finned fish. | there is general agreement that the polypteriform fishes, like polypterus senegalus, constitute a unique lineage in the evolution of the vertebrates. however, the precise position of these fishes had been a point of controversy since the time of darwin and huxley. there is now consensus that the polypteriform fishes are members of superorder actinopterygii. however, within the actinopterygii, it is still debatable as to whether the polypteriform fishes are an early offshoot of the actinopterygii ... | 2003 | 14636641 |
| an immunohistochemical study of the telencephalon of the senegal bichir (polypterus senegalus). | the telencephalon in ray-finned fish (actinopterygians) is everted, in contrast to the evaginated telencephalic hemispheres in all other vertebrates. in the more derived ray-finned fish, the teleosts, proliferation of neurons and their migration from the ependymal zone of the pallium renders comparisons between telencephalic cell groups of the teleosts and members of other vertebrate groups extremely difficult. the telencephalon of polypterus (a primitive living ray-finned fish), although everte ... | 1992 | 1351063 |
| [development of the cloaca and its ulterior transformations in the polypterids (pisces)]. | generally spoken cloacae have been but little studied. in polypterus, a brachiopterygian fish, a cloaca only exists during parts of the embryonal and larval life and it gets replaced by structures consisting of an anus and an urinary sinus. in the beginning of embryonal life the posterior opening of the body seems to be nothing else than the original blastoporus. the wall of this opening acquires evaginations; the anlagen of the excretory ducts come in contact with them, establishing in that way ... | 1975 | 1199896 |