Reptilian Cells Research Articles

Calbindin D28k in mammalian intestinal absorptive cells: immunohistochemical evidence

Calbindin D28k and D9k are two cytosolic calcium-binding proteins abundant in intestinal absorptive cells which appear to play a role in calcium translocation. Until today, calbindin D28k was found in avian and reptilian absorptive cells but not in mammalian ones. We have described the presence of calbindin D28k-immunoreactivity in intestinal absorptive cells of pig and jerboa (Jaculus jaculus). Pig calbindin D28k-immunoreactive absorptive cells were prominent in duodenum, they were scattered along the villi and nearly absent in the crypts. Jerboa labelled absorptive cells were located along the colonic mucosal surface. No calbindin D28k could be detected in mouse, rat and goat absorptive cells. Topography of calbindin D28k absorptive cells was compared with calbindin D9k distribution. Our results confirmed the data of the literature showing a gradient of labelling increasing from the crypt to the top of the villus and no positive endocrine cell. Young (48 h old) pigs did not expressed calbindin D28k in absorptive cells although calbindin D9k was detected. Calbindin D28K was also observed in endocrine cells which were numerous in pig and goat duodenum and very rare in mouse and jerboa. Western blot experiments confirmed the presence of calbindin D28k in the adult pig intestine, in the jerboa colon and the absence of cross-reactivity between calbindin D28k antibody and calbindin D9k.

Initiation and ultrastructure of a reptilian fibroblast cell line obtained from cutaneous fibropapillomas of the green turtle, Chelonia mydas.

Two fibroblastic cell lines were established from explants of fibropapillomas of each of two different green turtles (Chelonia mydas). These cells, designated GTFP (Green Turtle Fibropapilloma), were subcultured approximately 30 times at 30 degrees C in Eagle's minimal essential media supplemented with 2 to 10% fetal bovine serum. The ultrastructural morphology of the cultured fibroblasts is described. The cells contained abundant rough endoplasmic reticulum, polyribosomes, and mitochondria; collagen fibrils were visible in the extracellular space. No viruslike particles or evidence of other pathogenic agents could be demonstrated by electron microscopy in any of the cultured cells examined.

Evolution of mammalian endothermic metabolism: "leaky" membranes as a source of heat

O2 consumption was measured at 37 degrees C in tissue slices of liver, kidney, and brain from Amphibolurus vitticeps and Rattus norvegicus (a reptile and mammal with same weight and body temperature) both in the presence and absence of ouabain. O2 consumption of the mammalian tissues was two to four times that of the reptilian tissues and the mammalian tissues used three to six times the energy for Na+-K+ transport than the reptilian tissues. Passive permeability to 42K+ was measured at 37 degrees C in liver and kidney slices, and passive permeability to 22Na+ was measured at 37 degrees C in isolated and cultured liver cells from each species. The mammalian cell membrane was severalfold "leakier" to both these ions than was the reptilian cell membrane, and thus the membrane pumps must use more energy to maintain the transmembrane ion gradients. It is postulated that this is a general difference between the cells of ectotherms and endotherms and thus partly explains the much higher levels of metabolism found in endothermic mammals.

Ultrastructure of putative migrating cells in the cerebral cortex of Lacerta galloti.

Cells considered to be migratory in the cerebral cortex of adult lizards are ultrastructurally of two types. Nuclei in the first type have highly dispersed chromatin, creating a spongy appearance, whereas in the second type the chromatin is irregularly clumped. Both types of cells are closely associated with processes of radial ependymal glia cells, which perhaps orient their migratory pathways. Cells with spongy chromatin show an increase in cytoplasmic organelles and progressive chromatin condensation as they travel from the ependymal layer to the granular layer. Possibly these cells account for the neuronal increase that takes place in the granular layer during postnatal life. Cells with chromatin clumps are very scarce; ultrastructurally they resemble immature reptilian astroglia cells.

In situ ultrastructural localization of sugar‐binding sites in lizard granulosa cell nuclei

Mannose-binding sites were detected at the ultrastructural level in nuclei of lizard granulosa cells in situ by means of mannosylated ferritin. When ultrathin sections of material embedded in glycol methacrylate were incubated with mannosylated ferritin, a strong labelling was observed over nucleoli, chromatin and the external leaflet of the nuclear envelope, but no labelling was detected in the perinuclear space except for nuclear pores. This labelling was clearly inhibited when sections were incubated in a solution containing both mannosylated ferritin and a sugar-related neoglycoprotein (mannosylated serum albumin). These ultrastructural data supporting the existence of nuclear lectin-like components in reptilian cells are in agreement with our previous findings about such components in nuclei isolated from mammalian cells. Owing to the unique organization of the granular component of the nucleoli in specialized granulosa cells, we are able to show that some of the mannose-binding sites are associated with ribosomal precursors.

Interferon-mediated persistent infection of Saint Louis encephalitis virus in a reptilian cell line.

A persistent infection with Saint Louis encephalitis (SLE) virus in a poikilothermic cell line TH-1 (turtle heart cells) was studied. Infected TH-1 cells were subcultured weekly at 31 degrees C for 1 year and continued to produce low levels (10(2) to 10(3) p.f.u./ml) of virus without obvious cytopathic effects or marked cyclic events. Indirect fluorescent antibody and infectious centre assays indicated that less than 1% of the cells were producing detectable virus proteins or infectious virus. Defective-interfering particles, temperature-sensitive mutants and DNA provirus were not detected. Interferon (IFN) mediation of the persistent infection as considered since the persistently infected cells (PIC) and normal TH-1 cells were resistant to heterologous virus challenge after treatment with virus-free culture fluid from PIC. A direct relationship was found between the m.o.i. and the amount of IFN produced, plateauing at an m.o.i. of approx. 10. The reptilian IFN was physically and chemically similar to mammalian and avian IFN. Certain biological markers of the SLE virus changed during the persistent infection. It was less virulent for mice, showed distinct differences in cell culture host range and had increased thermal lability.

Fer de Lance virus (FDLV): a probable paramyxovirus isolated from a reptile.

A new virus has been isolated by inoculation of lung tissues of diseased snakes into snake embryos. Homogenates of infected embryo tissues caused c.p.e. in cell cultures incubated at 30 degrees C. The virus replicates in a wide variety of reptilian or mammalian cell types incubated at 30 degrees C, inducing either syncytium formation or minimal or no cytopathic changes. Efficient replication occurs in embryonated hens' eggs at 27 to 30 degrees C. The virus haemagglutinates guinea pig and chick erythrocytes; it possesses a neuraminidase similar to the receptor-destroying enzyme of Vibrio cholera. Electron microscopic observations of infected cells examined in thin section revealed pleomorphic viruses 146 to 321 nm in diam. resembling known myxoviruses. Internal nucleocapsid strands are 15 to 16 nm in diam.; nucleocapsid observed in negatively stained preparations measures 14 nm in diam. The virus was determined to possess a nucleoprotein core containing a 50S single-stranded unsegmented RNA genome. All characters of the virus are similar to those of the paramyxovirus group except that the nucleocapsid diam. is intermediate between that of paramyxoviruses and pneumoviruses. The virus is antigenically distinct from known myxoviruses and is unique among myxoviruses in its restriction to growth at temperature below 37 degrees C.

Propagation and Characterization of a C-Type Virus from a Rhabdomyosarcoma of a Corn Snake

SUMMARY The presence of a C-type virus in tissues of an embryonic rhabdomyosarcoma of a corn snake Elaphe guttata was previously described, based upon electron microscopic observations. A virus, corn snake retrovirus (CSRV) has been recovered from the tumour tissue by inoculation of a tissue homogenate on to either the rattlesnake fibroma cell line or early passage cells derived from rattlesnake heart or kidney. Attempts to cultivate the virus in other reptilian cell systems were unsuccessful. The virus was classified as a retrovirus on the basis of electron microscopic observations of fine structure and morphogenesis, and the demonstration of virion-associated reverse transcriptase and a buoyant density of 1.16. Polypeptide analysis of CSRV performed by polyacrylamide gel electrophoresis revealed the presence of five major polypeptides: three had mobility analogous to that of structural polypeptides of viper retrovirus (VRV) but two polypeptides, one of mol. wt. approx. 16000 and a glycoprotein of mol. wt. approx. 72000, were unique. Antigenic comparison of CSRV and VRV by agar gel immunodiffusion revealed that CSRV possesses a major antigenic determinant which is different to that of VRV. CSRV propagated in rattlesnake fibroma cells was demonstrated to be slowly cytopathic for rattlesnake heart and kidney cells in vitro.

Morphogenesis of Fer-de-Lance virus (FDLV) cultured at sub- (23°C) and supra- (36°C) optimal cell growth temperatures

FDLV, a recently isolated reptilian myxovirus, replicates at suboptimal cell growth temperature in one mammalian and four reptilian cell lines. At supraoptimal temperature only rattlesnake fibroma cells produced virus. Virion size, cytoplasmic nucleocapsid strands, and specific virus-related inclusion bodies are considered on a comparative basis with respect to host cell and temperature differentials.

Morphogenesis of Fer-de-Lance virus (FDLV) cultured at optimal (30 °C) cell growth temperature

The morphogenesis of Fer-de-Lance virus (FDLV), the only known myxovirus associated with ectothermic vertebrates, has been studied by thin section and negative-contrast staining electron microscopy in cells cultured at near optimal temperature for virus replication (30 °C). The degree of viral budding, virion size and shape, and relative amounts of cytoplasmic nucleocapsid and specific inclusion bodies have been compared in 4 reptilian cell lines. Morphological features of FDLV indicate that it belongs to the para- or metamyxovirus subgroup.

Phosphate compounds in reptilian and avian red blood cells; developmental changes

1. 1. Red blood cells were analyzed for ATP, 2,3-diphosphoglycerate and inositol polyphosphate at different stages of development of two birds; pigeon and Western gull, and several reptiles: Pacific Ridley, snapping and Pseudemys turtles; green iguana, yellow rat snake and American alligator. Other species were examined only as juveniles or adults: ostrich, Boa constrictor and the Nile and Moreleti crocodiles. The results were compared with the phosphate compounds found in red cells of adult man, rat and rabbit. 2. 2. The presence, concentration, and time of occurrence of diphosphoglycerate and inositol polyphosphate, separately or together, during development, provided new biochemical clues to evolutionary relationships. 3. 3. Remarkably large differences in the concentration of ATP in red cells during the development of an animal, and among different kinds of animals, could not be explained.

Ultrastructural analysis of the effect of alloxan on reptilian pancreatic cells

Intraperitoneal injection of alloxan into terrapinsTestudo horsfieldi andClemmys caspica in a dose of 300 mg/kg caused destructive and metabolic changes in cells of both the endocrine and exocrine parts of the pancreas. The granular cytoplasmic reticulum in the acinar cells and the mitochondria in the centroacinar cells underwent focal destruction. Hydropic degeneration developed in the B cells. Deposition of glycogen was found in all cells and nerve fibers and was abundant in the centroacinar and mucoid cells.

Participation of chloroplasts and mitochondria in virus reproduction and the evolution of the eukaryotic cell

The similarity of prokaryotic cells and the organelles of eukaryotes can be explained not only by the ordinary form of the endosymbiosis hypothesis, but also by another evolutionary model presented here. This model postulates that portions of DNA of an ancient prokaryote were transferred into the nucleus of the ancient eukaryote cell. In combination with prokaryotic DNA-encoded proteins and phospholipid membranes prokaryotic DNA may have given rise to a structure resembling a promitochondrion or a proplastid. The transfer of genetic material into the nucleus or the cytoplasm could have occurred via a virus-mediatich. This suggestion is in accordance with the reported association of chloroplasts and plant mitochondria with replication of some strains of tobacco mosaic virus, cucumber green mottle mosaic virus, barley stripe virus and tobacco rattle virus and with findings of virus-like particles in mammalian and reptilian cells as well as cells of Neurospora crassa. The terms “mitophages” and “plastophages” (“chlorophages”) are introduced to designate the viruses associated with mitochondria or plastids (chloroplasts) during some phase of development. Participation of virus-mediated DNA transfers can be suggested for endosymbiotic organellar origin also.

Studies on the blood of australian elapid snakes—II. Red cell enzymes and glycolytic intermediates

1. 1. Blood was obtained from four species of snakes Pseudechis prophyriacus (black snake) Psuedonaja nuchalis (brown snake) Notechis scutatus (tiger snake) and Austrelaps superbus (copperhead snake). 2. 2. Activities of several enzymes of the glycolytic pathway and the level of some glycolytic intermediates were measured. 3. 3. There was a wide variation within and between species of snakes. 4. 4. Level of reduced glutathione (GSH) was considerably higher in reptilian red cells compared to mammalian red cells.

Les pinéalocytes de mammifère: diversité, homologies, origine. Etude chez la taupe adulte ( Talpa europaea L.)

en An electron microscopic investigation of the pineal organ of an adult mammal (the mole Talpa europaa L.) revealed the presence of several types of pinealocytes sensu stricto. In comparing three of these with one another, on the one hand, and with typical and rudimentary photoreceptor cells, characteristic of the epiphysis cerebri of non-mammalian vertebrates, on the other hand, the following homologies can be drawn at the cellular level: homology between a cilium (9 + 0 pattern) and the outer segment, homology (shape, structure and polarity of the organelles) between a process of large diameter and the inner segment, homology between the cell bodies and other processes, and homologies between the vesicle-crowned lamellae and the synaptic ribbons. The presence of three principal types of pinealocytes and of intermediary types can be explained as the result of different stages of cell differentiation during ontogenesis, which are maintained in the adult. The ultrastructural homologies now established, suggest that ancestral reptilian photoreceptor cells are the forerunners of mammalian pinealocytes. Our results, in combination with those recently obtained by other authors studying pineal development, support the existence of a sensory cell line in the vertebrate pineal organ.

Host effect on vesicular stomatitis virus morphogenesis and “T” particle formation in reptilian, avian and mammalian cell lines

Host effect on vesicular stomatitis virus morphogenesis and “T” particle formation in reptilian, avian and mammalian cell lines

Host effect on vesicular stomatitis virus morphogenesis and “T” particle formation in reptilian, avian, and mammalian cell lines

The morphogenesis of vesicular stomatitis virus (VSV) in three reptilian cell lines (turtle heart, gecko lung, and viper spleen) was studied by thin section electron microscopy. Simultaneous growth studies were conducted in reptilian, chick embryo fibroblast, and BHK/21 cells to compare the yields of infectious VSV during serial passages. The mean length of gecko lung cell VSV measured from electron micrographs is statistically significantly shorter than that of VSV replicating in other reptilian systems studied. This observation, along with comparative growth studies, suggests the predilection of gecko lung cells to form "auto-interfering" truncated "T" rather than infectious "B" VS virions.

Comparative Morphology of Three Strains of Rabies Virions Propagated in the Reptilian Cell Line, VSW

Cell line VSW, derived from the spleen of a tumor-bearing Asian pit viper, spontaneously produces C-type virions budding from membranes, and similar virions that develop within mitochondria. Rabies virus has been determined to replicate more efficiently in VSW cells than in a variety of other cell types cultivated from reptiles, amphibians or fish. We have compared the morphology of three strains (CVS, ERA and HEP) of fixed BHK/21 cell-adapted rabies virus in VSW cells infected at a cell multiplicity of infection of 20 and incubated at 33&C for 8 days prior to fixation.

Ultrastructural studies of cell-virus interaction in reptilian cell lines. II. Distribution, incidence, and factors enhancing the production of intramitochondrial virions.

Ultrastructural studies of cell-virus interaction in reptilian cell lines. II. Distribution, incidence, and factors enhancing the production of intramitochondrial virions.

Fish rhabdovirus replication in non-piscine cell culture: new system for the study of rhabdovirus-cell interaction in which the virus and cell have different temperature optima.

The replication of three rhabdoviruses associated with diseases of fish has been demonstrated in cells of continuously cultivated non-piscine cell lines. Spring viremia of carp (SVC) virus and the salmonid fish viruses, Egtved and infectious hematopoietic necrosis virus, all replicated in mammalian WI-38 (human diploid cell strain) and BHK/21 cells and in cells of one or more reptilian cell lines at the temperatures commonly used to propagate these viruses in fish cells. The infections were cytopathic: SVC virus plaque assays may be performed in several types of mammalian cell culture. "Autointerference" apparently mediated by abortive "T" particle formation was observed during serial nondiluted passages of SVC virus in BHK/21 and TH1 cells, but not in RTG-2 or WI-38 cells. Optimal temperatures for replication of SVC and Egtved viruses in BHK/21 cells were identical to those determined in poikilothermic vertebrate cell cultures. However, these viruses replicated relatively more efficiently at suboptimal temperatures in "cold-blooded" vertebrate cells than in the hamster cells. Studies of [(3)H]uridine incorporation into uninfected BHK/21 cells incubated at different temperatures revealed that [(3)H]uridine uptake is sharply reduced at temperatures below 24.5 C. Growth curve studies of SVC virus in BHK/21 cells incubated at 23 C revealed that a clear-cut large excess of virus-induced [(3)H]uridine incorporation could be demonstrated in the absence of actinomycin D. Actinomycin D treatment (1 mug/ml) led to efficient inhibition of control cell [(3)H]uridine uptake, but also markedly reduced the total counts per minute of virus-induced [(3)H]uridine uptake, without depressing the yield of released infectious virus. Actinomycin D added to SVC virus-infected BHK/21 cell cultures at concentrations as low as 0.01 mug/ml caused a significant decrease in the level of virus-induced [(3)H]uridine uptake, despite the fact that this concentration is insufficient to efficiently suppress "background" cellular [(3)H]uridine incorporation.