| acrosome staining and motility characteristics of sterlet spermatozoa after cryopreservation with use of methanol and dmso. | in this study we describe acrosome staining and motility characteristics of fresh and cryopreserved sterlet (acipenser ruthenus l.) spermatozoa using soybean trypsin inhibitor-alexa conjugate fluorescent staining and computer-aided sperm analysis (casa), respectively. methanol or dimethylsulfoxide (dmso) were used as cryoprotectants. after cryopreservation a decline in sperm motility characteristics occurred, but no differential effect between cryoprotectant was observed. cryopreservation caused ... | 2008 | 18466892 |
| the hypothalamo-hypophysial system in acipenseridae. x. corticoliberin-like immunoreactivity in the hypothalamus and hypophysis of acipenser ruthenus l. | using the unlabeled antibody peroxidase-antiperoxidase (pap) technique at the light microscopic level the distribution of immunoreactive corticoliberin has been studied in the hypothalamus and hypophysis of the sterlet. corticoliberin-containing cells have been revealed in the nucleus tuberalis and to lesser degree in the nucleus preopticus of the hypothalamus. the majority of labeled cells is located subependymally or between the ependymal cells. some dendrites of corticoliberin-containing cell ... | 1985 | 3902561 |
| fine structure and vascular supply of the median eminence (me) in acipenser ruthenus (chondrostei). | the fine structure and vascular supply of the median eminence (me) was studied in 57 specimens of acipenser ruthenus (chondrostei) by means of light microscopy (normal histology, horseradish-peroxidase (hrp), formaldehyde induced fluorescence (fif), scanning electron microscopy (sem) and transmission electron microscopy (tem) as well as by sem of vascular corrosion casts. light microscopy revealed that the me increases in thickness from caudal to rostral with capillaries invading the subependyma ... | 1985 | 4031490 |
| design of cerebellar and nontegmental rhombencephalic microvascular bed in the sterlet, acipenser ruthenus: a scanning electron microscope and 3d morphometry study of vascular corrosion casts. | the design of the microvasculature of cerebellum and nontegmental rhombencephalic areas was studied in eight adult acipenser ruthenus l. by scanning electron microscopy of vascular corrosion casts and three-dimensional morphometry. gross vascularization was described and diameters and total branching angles of parent and daughter vessels of randomly selected arterial and capillary bifurcations (respectively, venous mergings) were measured. with diameters ranging from 15.9 +/- 1.9 microm (cerebel ... | 2006 | 16984664 |
| the role of the igf-i system for vitellogenesis in maturing female sterlet, acipenser ruthenus linnaeus, 1758. | transition from previtellogeneic to vitellogenic oocyte growth is a critical phase for folliculogenesis in sturgeon and may often be postponed for several years. recent findings on the involvement of insulin-like growth factor i (igf-i) in cell differentiation processes of oocyte follicle and ovarian steroidogenesis of teleosts in vitro led to the hypothesis that paracrine igf-i could function as a potential trigger in vivo. for the first time, igf-i and its corresponding receptor (igf-ir) were ... | 2007 | 16945369 |
| the hypothalamo-hypophyseal system in acipenseridae. xi. morphological and immunohistochemical analysis of nonapeptidergic and corticoliberin-immunoreactive elements in hypophysectomized sterlet (acipenser ruthenus l.). | the regeneration of the hypothalamo-hypophyseal system (hhs) has been studied in the sterlet following hypophysectomy (hypox). significant portions of nonapeptide and corticoliberinergic (crh) neurosecretory cells (nscs) underwent degeneration. surviving nscs had a great regenerative ability; damaged axons formed anew, uncharacteristicly for intact fishes, axovasal and axoventricular contacts. there are some specific features of the reorganization of the anhyp in sterlet after hypox: (a) blood c ... | 1997 | 9073493 |
| urotensin ii from the river lamprey (lampetra fluviatilis), the sea lamprey (petromyzon marinus), and the paddlefish (polyodon spathula). | urotensin ii was isolated from extracts of the whole brain of the river lamprey (lampetra fluviatilis) and the sea lamprey (petromyzon marinus). the primary structure of the peptide from both species is the same (asn-asn-phe-ser-asp-cys-phe-trp-lys-tyr-cys-val) and this amino acid sequence is identical to that of urotensin ii from the dogfish and skate. consistent with previous morphological studies indicating that the agnatha lack a caudal neurosecretory system, urotensin ii was not detected in ... | 1995 | 8536944 |
| chromosomal nucleolar organizer regions in four sturgeon species as markers of karyotype evolution in acipenseriformes (pisces). | nucleolar organizer regions in acipenser ruthenus (2n = 118 +/- 4) are localized on the telomeric regions of two morphologically different pairs of chromosomes. in a. baeri (2n = 250 +/- 8), a. transmontanus (2n = 248 +/- 8), and a. naccarii (2n = 246 +/- 8) they are localized on eight chromosomes arranged in two quadruplets. contrary to what is commonly accepted, such distribution suggests that species with 120 chromosomes should be considered diploids and species with 240-250 chromosomes shoul ... | 1994 | 18470132 |
| retinopetal projections from diencephalic neurons in a primitive actinopterygian fish, the sterlet acipenser ruthenus. | horseradish peroxidase (hrp) injections into the sterlet (acipenser ruthenus) retina retrogradely label neurons in the dorso-medial thalamus, bilaterally. on the contralateral side, 5-7 cells were labelled, whereas ipsilaterally, only 2-3 cells were backfilled. such diencephalic retinopetal cells have, so far, only been found in teleosts and in tetrapods. it has, therefore, been suggested that they evolved independently in these two vertebrate groups. our findings on a primitive actinopterygian ... | 1993 | 8255541 |
| evolution of the nucleolar apparatus during oogenesis in acipenseridae. | evolution of the nucleoli has been followed during oogenesis in the acipenserid fishes, acipenser ruthenus (the sterlet) and a. guidenstadti (the sturgeon) using light and electron microscopes. in the ovaries of adults, the oogonial nuclei usually have a single nucleolus with an adjacent mass of paranucleolar fibrillar material. the cytoplasm of the oogonia contains two dense bodies peculiar only to gonocytes, one being electron dense and containing rna and the otherbeing electron-lucent and lac ... | 1976 | 985850 |
| [localization of cells connected with different tropic functions in the hypophysis of the young of huso huso l. x acipenser ruthenus l., chondrostei]. | a number of histological and histochemical methods were used in order to detect different secretory cells in the hypophysis of young huso huso l. x acipenser ruthenus l., chondrostei. special attention was given to somatotropic cells. for their detection the following staining methods were used: orange g - acidic red 2c - acidic green g after fixation in the mixture of hgcl2 with formalin. in the dorsal part of the hypophysis having the appearance of vertical folds pressed into the hypophysis fr ... | 1976 | 971119 |
| [electron microscopic study of the olfactory organ of the sterlet (acipenser ruthenus)]. | three variations of olfactory cells were found in the olfactory organ of the sterlet acipenser ruthenus. they were different in the shape of their peripheral processes: rod-shaped ones supplied with flagella and solitary microvilla; cone-shaped ones with solitary flagella and a great number of microvilla; filiform ones without flagella but with numerous microvilla and groups of centrioles in the cytoplasm of the peripheral process. the character of the structural and functional organization of t ... | 1975 | 1200864 |
| ultrastructure of neurosecretory cells at different stages of differentiation in the preoptic nucleus of immature sterlet. | ultrastructure of neurosecretory cells of the preoptic nucleus in immature sterlet (acipenser ruthenus l.) was studies for the first time. the dorsal zone of the preoptic nucleus houses light, dark, and pycnomorphic neurosecretory cells, which contain varying numbers of elementary secretory granules measuring 1995 plus or minus 32 a in diameter. light cells containing numerous secretory granules with a diameter of 1707 plus or minus 27 a are predominant in the middle zone. pycnomorphic cells are ... | 1975 | 1124423 |
| [head blood vessels of the sterlet (acipenser ruthenus l.) (acipenseridae, chondrostei)]. | | 1973 | 4730634 |
| the genus acipenser as a model for vertebrate urogenital development: ultrastructure of nephrostomial tubule formation and of initial gonadogenesis. | the ultrastructure of the nephrostomial tubule and the gonadal crest of acipenser ruthenus were studied by transmission and scanning electron microscopy. opisthonephric nephrostomial tubules begin to appear at the end of the first week after hatching and are regularly segmentally arranged and completely developed in the period between 10 and 35 days after hatching. fully differentiated nephrostomial tubules connect the vestibular area of the malpighian corpuscle with the coelomic cavity as short ... | 2002 | 12392324 |
| a method for hypophysectomy in the young sturgeon acipenser ruthenus l. | | 2003 | 5154595 |
| [histologic studies on the gonads, thyroid gland, and pituitary in acipenser ruthenus in natural conditions in ponds and rivers]. | | 1953 | 13095293 |
| comparative scanning electron microscopy of the ventricular surface in four actinopterygian fishes: acipenser ruthenus, salmo gairdneri, tinca tinca and blennius sanquinolentus (pisces). | the ventricular surface structure of the brains of actinopterygian fishes representing four distinct evolutionary levels was investigated by scanning electron microscopy (sem). in the chondrostean acipenser ruthenus ventricular spaces are wide and the ependymal surface is for the greater part densely covered with cilia; apart from macrophages supraependymal cells (se) are very scarce. in the teleosts salmo gairdneri, tinca tinca and blennius sanquinolentus the ventricles are slit-like, the dense ... | 1985 | 3989278 |
| distribution of aminergic neurons in the brain of the sterlet, acipenser ruthenus (chondrostei, actinopterygii). | aminergic nuclear areas were identified in the brain of acipenser ruthenus using formaldehyde-induced fluorescence (fif). one group of scattered, green fluorescent cerebrospinal-fluid (csf)-contacting neurons is located rostral to the commissura anterior. a second very prominent field of green fluorescent neurons is situated within the recessus preopticus, the recessus preopticus organ (rpo). caudal to the latter there is a group of green and yellow fluorescent csf-contacting neurons, the anteri ... | 1985 | 2859310 |
| [crown cells in the diencephalon of acipenser ruthenus (acipenseridae, chondrostei)]. | crown cells are considered to be typical for the saccus vasculosus of gnathostome fishes. in acipenser ruthenus these cells could be found on the entire floor of the diencephalon by sem. there is one accumulation of crown cells in the frontal recessus praeopticus, one caudal to the optic chiasma and one on the floor of the recessus lateralis. the number of apical processes of the crown cells decreases significantly according to their distance from the saccus vasculosus. in all basal gnathostome ... | 1983 | 6672098 |
| [interrenal tissue reaction of the hypophysectomized sexually mature sterlet (acipenser ruthenus l.) to salt exposure]. | to corroborate the direct influence of hypothalamic nanopeptides on the peripheral endocrine glands (the phylogenetically ancient paraadenohypophyseal pathway of regulation) under a prolonged stress as hypothesized by polenov, sexually mature male and female sterlets, intact and hypophysectomized 4 months previously were placed into 6% nacl solution for 10 days. an activation of the interrenal tissue occurred both in intact and hypophysectomized fish as evidenced by increased nuclear volume of t ... | 1982 | 7117622 |
| [age and changes in the structure of the neurohypophysis of the sterlet, acipenser ruthenus l]. | the results are given of histophysiological study of neurohypophysis in sexually mature sterlets (acipenser ruthenus l.) of different age. an attention is paid to the age morphological changes of neurohypophysis and, in particular, to the number, size and topography of large and giant widenings of neurosecretory fibers, so-called gerring bodies. the relation between the frequency of gerring bodies and the age of fishes was followed. a suggestion is put forward to the effect that the appearance o ... | 1977 | 882241 |
| [receptor cells of different types and quantitative relations between them in the organ of smell of larval and adult specimens of acipenserid fishes]. | three types of olfactory cells: rod-like and cone-like (flagellar olfactory cells) and filamentous (microvillar olfactory cells), which have been described previously in adult acipenseridae were found in the olfactory organ of the ten-days larval sturgeons (acipenser güldenstädti), sevrugas (acipenser stellatus) and sterlets (acipenser ruthenus). the flagellar olfactory receptors appeared to predominate in both ten-days larvae and adults of the anadromous sturgeons and sevrugas, while the microv ... | 1976 | 1030860 |