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PubMed1976

[Evolutionary transformations of the esophageal lining in vertebrates and man in light of the theory of phylembryogenesis].

The comparative histological study of processes of embryonic histogenesis of the oesophagus epithelium in certain representatives of vertebrate animals (fishes, amphibia, reptiles, birds, mammals) and man was carried out in the light of the academician A. N. Severtsov's theory of phylembryogenesis. It has been shown that phylogenetic changes of the oesophagus lining of vertebrates related with its evolutionary transformations are regularly reflected in the stages or steps of the oesophagus epithelium histogenesis in ontogenesis of each systematic unit of the subtype. The first step is the phylembryogenesis of the oesophagus lining in all vertebrates is the monolayer epithelium of the endodermal origin; the secone step is the striated muco-ciliated (in low vertebrates and most reptiles) and pseudostratified (embryos of higher vertebrates) epithelium; the third step is the pseudostratified mucous epithelium (bony fishes) and stratified lining (prefetuses of higher vertebrates). The forth step is the stratified mucous (steppe turtle) and stratified muco-ciliated epithelium (fetuses of birds, many mammals and man). The fifth step--stratified squamous epithelium (birds, mammals, man). The academician A. N. Severtsov's theory of phylembryogenesis clearly points to the origins (the entoderm), routs and mechanisms of the transformation of the oesophagus lining in its evolutionary development.

Amphibians↗
PubMed1976

Regulation of extracellular potassium concentration in epileptogenesis.

Characteristic elevations in the brain's extracellular potassium concentration [K+]0 occur during focal epileptogenesis. These changes have particular spatial and temporal profiles that are different in hippocampus and neocortex, and in mature and immature animals. Increases in [K+]0 cannot be the sole explanation for regional variations in seizure susceptibility, interictal-ictal transitions, or termination of ictal episodes. Excess [K+]0 is cleared primarily by passive diffusion with a small amount taken up into cells and blood vessels. Cortical neuroglia have sensitivities to changes in [K+]0 similar to that observed in glial cells in invertebrates and amphibia. However, discrepancies in the expected relationship between [K+]o and glial membrane potential Vm suggest either a heterogeneous population of glial cell types and/or the presence of a glial syncytium which acts as a spatial buffer to increases in [K+]0.

Animals↗
PubMed1993

Cellular and nuclear volume of primitive red blood cells in digynic and diandric triploid and control diploid mouse embryos.

It has long been known that a relationship exists between ploidy and cellular and nuclear volume. This has been observed in amphibia and plants, and more recently in postimplantation tetraploid mouse embryos. We wished to establish whether a similar relationship exists in digynic and diandric triploid mouse embryos, as well as establishing whether the cellular or nuclear volume of primitive nucleated red blood cells of these two classes of triploids were the same. Spontaneously occurring digynic triploid embryos isolated from LT/Sv strain female mice result from the fertilisation of primary oocytes. These embryos develop to the forelimb-bud stage but invariably possess neural tube and cardiac abnormalities. Diandric triploid embryos were also analysed, and were produced experimentally by standard micromanipulatory techniques. They have a relatively normal morphology, and can survive up to the forelimb--bud stage. Primitive red blood cellular and nuclear volume was analysed in serially sectioned digynic and diandric triploid and in developmentally matched diploid control embryos isolated both as littermates of triploid embryos from LT/Sv strain mice, and from other genetically dissimilar diploid controls. The triploid and diploid embryos were analysed between 8-8.5 and 10-10.5 days of gestation, respectively. The cellular and nuclear volumes of the primitive red blood cells in the digynic and diandric triploid embryos were not significantly different, though they were significantly greater than comparable measurements for diploid embryos. We have therefore confirmed that a predictable relationship exists between cellular and nuclear volume and ploidy in the material analysed. The red blood cellular volume in triploid and diploid embryos increased in a predictable way over time, while their nuclear volume decreased in a predictable way over the same time period. A similar relationship has previously been observed when the nucleated red blood cells of diploid and tetraploid embryos were analysed morphometrically.

Animals↗
PubMed1977

[Bioelectrical activity and automatic properties of different parts of a two-chambered heart].

Two pacemakers localized in sinoatrial and atrioventricular valves were revealed in the tench heart. In their absence, the ventricular and sometimes the atrial myocardium are capable of initiating the automaticity. Pacemaker's cells of the sinoatrial valve are surrounded by specific area similar to sinoauricular ring in amphibia or sino-caval region in mammals. Characteristics of the action potential in different parts of the tench heart are presented.

Animals↗
PubMed1996

Vitelline envelope formation during oogenesis in Bufo arenarum.

The formation of vitelline envelope (VE) during the oogenesis of Bufo arenarum (Amphibia Anura) is described. At the stage of early vitellogenesis, the first structures appear: the number of oocyte microvilli increases, and many cross sections of them are observed between the follicle cells and the oocyte. A filamentous material is observed inside the follicle cells and between the follicle cells and the oocyte. Multivesicular bodies are also found in the follicle cells, and in the perivitelline space. The micrographs also suggest the participation of the oocyte in the process of VE formation: large vesicles are present in the cortex of the oocyte, filled with an amorphous material of low and uniform electron density. Some of them are in the process of releasing their content to the perivitelline space. Many vesicles (probably resulting from microvilli fragmentation) are also observed in the perivitelline space. During late vitellogenesis the VE is a continuous structure between the layer of follicle cells and the oocyte. The filamentous material is aggregated in bundles, forming a net, and the spherical components are now either included in the orifices of the net, or free near the oocyte's surface. At the end of oogenesis, when the VE is completely formed, it is difficult to distinguish its components independently. Immunolocalization with antibodies against VE, show a positive reaction in follicle cells and oocytes in previtellogenic and full grown ovarian follicles. This analysis suggests that both the oocyte and the follicle cells are directly involved in the synthesis and secretion of the components of the vitelline envelope in Bufo arenarum.

Animals↗
PubMed1995

Extrathymic T cells stand at an intermediate phylogenetic position between natural killer cells and thymus-derived T cells.

A series of recent studies have revealed that extrathymic pathways of T cell differentiation exist at multiple sites in mice and humans. In terms of their properties, extrathymic T cells may stand at an intermediate position between natural killer (NK) cells and thymus-derived T cells in phylogenetic development. It is speculated that primitive lymphocytes such as NK cells and extrathymic T cells develop from primordial macrophages in intraepithelial regions of e.g., the intestine, skin and liver. In this regard, the immune system of the bone marrow and thymus is relatively recent, developing after the emergence of living beings onto the land (i.e., amphibia). A complete elimination of self-reactive T cell clones occurs in mainstream intrathymic T cell differentiation and a consistent generation of such clones occurs through the extrathymic pathways. Therefore, thymus-derived T cells are efficient for processing foreign antigens, whereas extrathymic T cells recognize abnormal self-cells. Although thymus-derived T cells play the major role in youth, extrathymic T cells may play rather a pivotal role with aging and under conditions of malignancy, intracellular infections, pregnancy, and autoimmune diseases.

Animals↗
PubMed1996

Contrasting effects of anesthetics in tadpole bioassays.

The median anesthetic concentrations (AC 50 values) in the bath solution for loss of righting reflex (RR) or nociceptor response (NR) were determined in larval Rana catesbeiana. The AC50 (NR)/AC50(RR) ratios were between 1.6 and 1.9 for ethanol, ether and diazepam. Comparable ratios for hexobarbital and thiopental were 9.8 and 6.2, which indicated a marked lack of "analgesic" effect. The tadpole AC50 values were consistently higher than AC50 values reported for nonionized and unbound drug in mammalian blood water. The tadpole/mammal ratio for loss of NR during thiopental anesthesia was approximate 8, and analysis of ventricular blood showed that the ultrahigh bath concentrations of thiopental were in equilibrium with those in tadpole serum. The tadpole/mammal ratio for diazepam was approximate 110, and its effect in the tadpole was not reversed by flumazenil. Tadpole/mammal ratios for ethanol and ether were approximate 2. Ethanol and ether showed additive effects when tested in combination, and ethanol-tolerant tadpoles showed a similar tolerance to ether. In contrast, hexobarbital and ethanol showed supra-additive effects, and ethanol-tolerant tadpoles showed a greater tolerance to hexobarbital than to ethanol or ether. These studies show marked differences in effect between barbiturates and the ethanol-ether group, high-concentration benzodiazepine effects presumably independent of a specific receptor, and marked differences in drug potency between amphibia and mammals.

Anesthetics↗
PubMedDate not supplied

[Articles published in the Archives d'Anatomie, d'Histologie et d'Embryologie from volume 1 (1922) to volume 74 (1991-92)].

Three anatomists followed one another as Chief Editor of the Archives: Professor A. Forster (Strasbourg) from volume 1 (1922) to volume 29 (1940), Professor G. Winckler (Lausanne) from volume 40 (1957) to volume 53 (1970), and Professor J. G. Koritké (Strasbourg) from volume 54 (1971) to volume 74 (1991-92). From the outset, the Archives received papers from distinguished French and foreign anatomists. The Archives also constitute, since their origin, one of the preferential organs of expression for the Strasbourgian morphological works. All fields of morphology are represented. All zoological groups are concerned, some Invertebrates, but principally Vertebrates: Fishes, Amphibia, Reptiles, Birds, and Mammals amongst which the human species occupies a priviliged place. A total of 938 papers has been published in the Archives. Most papers are in French (833 i.e. 89.0%). Papers in English (89 i.e. 9.5%) are more numerous in the most recent volumes; other papers are in Italian (11 i.e. 1.0%) and in German (5 i.e. 0.5%).

Anatomy↗
PubMed1997

The phylogenetic odyssey of the erythrocyte. IV. The amphibians.

Amphibians manifest permanently nucleated, oval, flattened, biconvex erythrocytes. These cells demonstrate a cytoskeleton which is responsible for their morphogenetic conversion from a sphere to an ellipse and imparts to their cellular mass reversibility of traumatic deformation. The class Amphibia has the largest of all erythrocytes attaining volumes greater than 10,000 femtoliters in the Amphiuma. The large dimensions reflect evolutionary processes, genomic size, ploidy and the relative size of other somatic cells. Conversely, the erythrocyte count and hemoglobin concentration of these species are low. Occasional denucleated red cells can be seen in the peripheral blood but may attain levels of 90-95% of the total circulating population in certain members of the tribe Bolitoglossini (e.g. Batrachoseps attenuatus). These erythroplastids retain the marginal band thus remaining different from mammalian erythrocytes. Embryologically, erythropoiesis initiates in the yolk sac and then progresses to the kidney, liver, and possibly spleen. The yolk sac cohort is transitory and is successively replaced by the larval and definitive populations of erythrocytes. Red cell production (along with thrombocytopoiesis) in adult urodeles is conducted intravascularly in the spleen. In anurans this organ is usually the major site although the liver also serves as a secondary locus for this activity. Medullary (bone marrow) erythropoiesis makes its phylogenetic debut in anurans and typically occurs during heightened hemopoiesis following metamorphosis or hibernation. Maturation of the erythrocyte in the circulation is commonplace (especially in urodeles) while proliferation at this site is inducible by splenectomy and/or hemolysins. Erythrocyte-related values demonstrate variable differences associated with age, weight, season, gender, and environment.

Amphibians↗
PubMed1997

Diverse roles for the Notch receptor in the development of D. melanogaster.

Notch proteins appear to be involved in cell fate commitments with deep evolutionary roots. Homologues have been shown to play key roles in the development of nematodes, insects, amphibia, and mammals. Activity of the Notch receptor has been observed in the patterning of ectoderm, mesoderm, and endoderm, indicating an origin prior to the functional differentiation of these germ layers. To understand how a single receptor can participate so widely in development, we have been examining the role of specific extracellular segments of Notch. Early studies of mutations affecting widely separated EGF-like elements of Notch first raised the possibility for interaction with multiple ligands. Biochemical approaches, and exhaustive structure function studies in transgenic Drosophila are beginning to reveal how this receptor is activated, and point to a range of physical interactions with other proteins.

Animals↗
PubMed1996

The use of water chemistry and benthic diatom communities for qualification of a polluted tropical river in Costa Rica.

The water quality of several sections of a tropical river subjected to severe pollution was studied through physico-chemical water analysis and benthic diatom assemblages. The methodology follows the concept of differential species groups and that of its modification for the groups of nutrient-differentiating species for rivers rich in both oxygen and inorganic nutrients. The trophic indication of the latter authors correspond clearly with the results of chemical observations made in this study. The most abundant species found in this river were Navicula goeppertiana, Gomphonema parvulum, Gomphonema sp. aff. pumilum, Nitzschia palea, Nitzschia amphibia, Nitzschia clausii Nitzschia inconspicua, Navicula seminulum, Navicula sp. aff. cryptocephala, Navicula schroeterii var. escambia, Cymbella sinuata and Surirella sp. aff. roba. These species are known to be tolerant to organic pollution and eutrophication. Therefore we may conclude that diatoms are useful for biological monitoring of disturbed tropical rivers.

Animals↗
PubMed1979

[Immunohistochemical identification of specific antigens in stained and balsam-embedded eye lens sections].

Localization of specific proteins at preliminary stained with azan and embedded in balsam sections of amphibian eye lens (Rana temporaria, Xenopus laevis) was studied by indirect immunofluorescence. The analysis was performed on the lens of intact animals as well as on lens induced in amphibia gastrula ectoderm in vitro. To remove balsam the lens sections were successively washed by xylene, ethanol and saline (pH 7.1). Then they were treated according to the general principles of immunohistochemical analysis. Specific antigens have been thus shown to be detectable at lens sections which had been kept in balsam for over a year. The immunofluorescent reaction to lens proteins was negative at more prolonged storage of the sections (2--3 years).

Animals↗
PubMed1997

Adaptive evolution of water homeostasis regulation in amphibians: vasotocin and hydrins.

Volemia and osmolality homeostasis is ensured in vertebrates through neuroendocrine reflexes, involving an afferent neural branch from baro- and osmo-receptors to hypothalamus and an efferent endocrine branch from secretory neurons to target hydroosmotic cells equipped with receptors and effectors. Whereas the osmoregulatory system in the tadpole comprises three organs, namely gut, kidney and gills, as in freshwater fishes, the adult displays a quaternary strategy with gut, kidney, urinary bladder and skin. In particular, the cutaneous permeability entails a great evaporative water loss when the animal is in the open air, loss that must be compensated by water reabsorption through the nephron and the urinary bladder and mainly by water uptake through the skin. Adaptation occurred at the level of these organs by regulation of their permeability through neurohypophysial hormones. Aside from vasotocin, active on the three organs, all anuran Amphibia possess hydrin 2 (vasotocinyl-Gly), a peptide resulting from a down-regulation of provasotocin processing. Exceptionally Xenopus laevis, a permanent aquatic toad, has hydrin 1 (vasotocinyl-Gly-Lys-Arg) instead of hydrin 2. Hydrins are somewhat more active than vasotocin on water permeation of skin and bladder but are devoid of antidiuretic activity. Adaptive evolution has created, along with the vasotocin-nephron system, preserved in all terrestrial non-mammalian tetrapods, additional functions such as the hydrin-skin and hydrin-bladder rehydration mechanisms. Specific hydrin receptors might exist in the skin and the bladder, different from those of vasotocin in the kidney. It is assumed that the water channel recruitment mechanism, found for vasopressin acting on the collecting duct principal cells in mammals, is also involved when vasotocin and hydrins stimulate their hydroosmotic target cells and that hormone-regulated aquaporin 2-like proteins could be identified in the three osmoregulatory organs of amphibians.

Adaptation, Physiological↗
PubMed1976

Transition from the polikilotherm to the homeotherm: possible role of sodium transport and thyroid hormone.

The evolutionary transition from poikilothermy to homeothermy required the recruitment of complex mechanisms that provided both higher rates of heat production and regulation of heat loss in the presence of wide variations in ambient temperature. Two pathways that have been considered to be contributors to the transition to homeothermy are thyroid-regulated thermogenesis and nonshivering thermogenesis in the adaptation to cold. These pathways may yield higher rates of heat production in homeotherms by two processes that need not be mutually exclusive: a) hydrolysis of ATP and consequent generation of the Pi acceptor--ADP, or b) decreased coupling of mitochondrial oxidative phosphorylation. A significant fraction of both thyroid and catecholamine thermogenesis has been ascribed to enhanced energy expenditure in active transmembrane Na+ transport (i.e., the Na+ pump). By extension these findings implicate the Na+ pump as a heat source in the evolution of the homeotherms. The thermogenic response to thyroid hormone is both rapid and profound in homeotherms (mammals), and more slowly evident and probably lesser in magnitude in poikilotherms (amphibia and reptiles). One crucial pathway in the evolution to homeothermy may be nonshivering thermogenesis in response to cold. In mice, most of the elevated rate of oxygen consumption of liver and skeletal muscle elicited by cold exposure is ouabain-sensitive. Thus, the Na+ pump appears to be an important heat source in the transition to homeothermy. The underlying biochemical mechanisms that mediate the contribution of the Na+ pump to heat production, including responsiveness to thyroid hormone and catecholamines, however, may not be unique to the homeotherms.

Adaptation, Physiological↗
PubMed1998

A protein kinase inhibitor from A431 subline overexpressing TGF alpha possesses antimicrobial activity.

During the last decade the key role of antimicrobial peptides in innate immunity has been argued. They were found in plants and in different phylogenic groups of animals (insects, amphibia, and even in mammals). We report the production of a human peptide antibiotic that was previously characterized as an EGF receptor tyrosine kinase inhibitor in epidermoid carcinoma A431/1522 cell subline overexpressing TGF alpha. It is a 3 kDa hydrophobic cationic peptide cytotoxic for different species of Gr+ and Gr- bacteria in micromolar concentration range, and demonstrating slight fungicidal activity.

Anti-Bacterial Agents↗
PubMedDate not supplied

[The distribution of Blastocystis according to different systematic groups of hosts].

After the carried out examination of different animals belonging to four phyla, Annelida, Mollusca, Arthropoda, and Chordata, the blastocysts were detected within three phyla, Annelida, Arthropoda, and Chordata. Within the phylum Annelida the blastocysts were found in Hirudinea, within the phylum Arthropoda--in Insecta, within the phylum Chordata--in Amphibia, Reptilia, Aves, and Mammalia.

Amphibians↗
PubMed1976

[Patterns characterizing different levels of animal organization].

The article deals with features of the regularities characterizing different levels of organization of the animal body. The cell is not only an integrated but also indivisible organic integrity which is due to the interaction of the nucleus and cytoplasm determining all sides of its vital activity. From this viewpoint the results of experiments on transplantation of the embryo cell nucleus into an enucleated egg of amphibia and the data on somatic hybridization are estimated. All processes of the cell life, their growth, multiplication and differentiation develop within the tissue system and are determined by the regularities of its development. The integrated system of the organism of a multicellular animal unites all the forms of integration of multi-step systemic pattern at different organization levels. Among different categories the systems of tissues and their interaction within the organ are most integrated. The regularities of the tissue development can not be brough to the regularities of the development of the anatomical structure of organs. The integration of cell elements in a tissue system and intertissue relations is the basis of all forms of interdependence in the cell development and the organism structure.

Animal Population Groups↗
PubMedDate not supplied

Oviduct structure and function and reproductive modes in amphibians.

The structure and function of the oviducts of members of the three Orders of the Class Amphibia (Anura, frogs and toads; Urodela, salamanders and newts; Gymnophiona, caecilians) are well described for only a few species. Further, the majority of such descriptions relate only to temperate species that breed in water, lay their eggs there, and have free-living larvae, the presumed ancestral condition of oviparity. Many species of amphibians have derived reproductive modes. Such modes include breeding terrestrially and arboreally, making foam nests, parental transport of eggs and/or tadpoles, direct development (copulating on land, laying the eggs in terrestrial sites, fully metamorphosed juveniles hatching, obviating the free-living larval stage). Other derived modes are ovoviviparity (developing embryos retained in the oviducts, born at a diversity stages of development, no maternal nutrition in addition to yolk) and viviparity (oviductal retention of developing young, maternal nutrition after yolk is resorbed, young born as fully metamorphosed juveniles). The amphibian oviduct is regionally differentiated to secrete varying numbers of layers of material around each egg, which function in fertilization, etc.; it is responsive to endocrine output and environmental mediation during the reproductive cycle; and it maintains developing embryos in some members of all three orders, some with oviductal epithelial secretion of nutrients. However, little is known of the structure-function relationships of the oviduct in species with derived reproductive modes. A comparison of oviduct morphology, function, endocrinology, ecology and phylogeny in amphibians with diverse reproductive modes suggests a number of highly productive avenues of investigation.

Amphibians↗