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  • 1
    Electronic Resource
    Electronic Resource
    A factor potentiating serotonin in the induction of germinal vesicle breakdown in surf clam oocytes (1987)
    Springer
    Cellular and molecular life sciences 43 (1987), S. 885-886 
    Details
    ISSN: 1420-9071
    Keywords: Spisula solidissima ; oocyte maturation ; germinal vesicle breakdown ; serotonin ; 5-hydroxytryptamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Simultaneous addition of an aliquot of body fluid obtained from the surf clam,Spisula solidissina, enhanced oocyte germinal vesicle breakdown induced with serotonin but not with KCl. When the body fluid and serotonin were added sequentially to the oocytes, potentiation did not occur. Body fluids of both males and females were effective at a 200-fold dilution. The factor is stable when treated with heat, acid, base, trypsin and pronase. It is hydrophobic and not dialyzable through tubing with a molecular weight cutoff of 1000 daltons. The factor is probably not a protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01951650
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  • 2
    Electronic Resource
    Electronic Resource
    Annual reproductive cycle of the captive female Japanese sardineSardinops melanostictus: Relationship to ovarian development and serum levels of gonadal steroid hormones (1991)
    Springer
    Marine biology 108 (1991), S. 21-29 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gonad and blood samples were taken from the captive female Japanese sardineSardinops melanostictus between 1988 and 1989, and changes in serum levels of gonadal steroids were correlated with the annual gonadal cycle. Under captive conditions, female fish did not mature and spawn spontaneously, although oocytes developed up to the end of vitellogenic growth. Based on evidence from ovarian histology, the annual gonadal cycle of the Japanese sardine was divisible into four periods, i.e., immature (June to October), vitellogenesis (November to December), spawning (January to March), and post-spawning (April to May). The pattern of seasonal change in the gonadosomatic index (GSI) showed an inverse correlation to change in water temperature and reflected the degree of ovarian maturity. The serum estradiol-17β level increased from its lowest concentration (0.12 ng ml−1) in September to a peak (1.14 ng ml−1) in March. Serum 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-P) was detectable at low levels (〈0.3 ng ml−1) between October and February, but was below the assay detection limit (0.06 ng ml−1) at all other times. Testosterone was not detectable (〈0.06 ng ml−1) in the serum of any fish throughout the year. The effects of several steroids on the maturation of follicle-enclosed oocytes of sardine were examined in vitro, and 17α,20β-P was found to be the most potent inducer of maturation. This suggests that post-vitellogenic oocytes of the Japanese sardine in captivity have an ability to respond to an appropriate hormonal effector and subsequently to resume meiotic maturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01313467
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  • 3
    Electronic Resource
    Electronic Resource
    Immunolocalization of steroidogenic enzymes (P450scc, P450c17, P450arom, and 3β-HSD) in immature and mature testes of rainbow trout (Oncorhynchus mykiss) (1998)
    Springer
    Cell & tissue research 292 (1998), S. 573-577 
    Details
    ISSN: 1432-0878
    Keywords: Key words Steroidogenic enzymes ; Testis ; Leydig cell ; Sertoli cell ; Germ cell ; Oncorhynchus mykiss (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  We examined the localization of steroidogenic cells in rainbow trout (Oncorhynchus mykiss) testis during spermatogenesis by using polyclonal antibodies generated against rainbow trout cholesterol side-chain cleavage enzyme cytochrome P450 (P450scc), 3β-hydroxysteroid dehydrogenase (3β-HSD), 17α-hydroxylase/C17,21 lyase (P450c17), and aromatase cytochrome P450 (P450arom) as markers of steroid production. Since we had previously produced specific antibodies against 3β-HSD and P450arom, antibodies against oligopeptides corresponding to C-terminal sequences of P450scc and P450c17, predicted from rainbow trout P450scc and P450c17 cDNAs, were produced in this study. These two antibodies recognized 54-kDa (P450scc) and 59-kDa (P450c17) bands specifically in several steroidogenic organs, i.e., testis, ovary, and interrenal tissue (head kidney) in Western blots. Immunohistochemically, immunoreactive P450scc, P450c17, and 3β-HSD, but not P450arom, were found only in interstitial Leydig cells of immature and mature testes. Immunoreactive P450arom was not detected in either testis. This study suggests that Sertoli cells and germ cells of rainbow trout testis do not contain P450scc, P450c17, P450arom, or 3β-HSD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051086
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of cycloheximide on preprophase bands and prophase spindles in onion (Allium cepa L.) root tip cells (1996)
    Springer
    Protoplasma 192 (1996), S. 109-121 
    Details
    ISSN: 1615-6102
    Keywords: Allium cepa L. ; Cell cycle ; Cycloheximide ; Preprophase band ; Root meristems ; Spindle microtubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Effects of cycloheximide (CHM) on preprophase bands (PPBs) of microtubules (MTs) and on prophase spindle MTs in root tip cells of onion (Allium cepa L.) were examined. When root tip cells were treated with 36 μM CHM for 0.5–4 h, the population of cells with a PPB did not decrease markedly although the population of mitotic cells and that of prophase cells with a PPB gradually decreased to half of the control root tips. In prophase cells treated with 11 and 36 μM CHM for 2 h, the width of the PPB was 1.4 times broader than that in the prophase PPB without CHM. Electron microscopic observation on the cross section of the PPB showed that the number of MTs and the distance between adjacent MTs in prophase PPBs treated with CHM were similar to those in the early developmental stage of PPBs without CHM. The bipolar spindle, that appeared in late prophase was not seen in prophase cells treated with 11 μM or higher concentrations of CHM for 2 h. In order to examine differences of perinuclear MT arrangement between CHM treated and non-treated prophase cells, arrangement of perinuclear MTs was examined by confocal laser scanning microscopy. In control cells without CHM, MTs appeared on the nuclear surface with several “branched” or “cross over” type MT foci in the cytoplasm when broad PPB formation started. These MT foci were replaced by the “aster” type MT foci, from which several MTs radiated along the nuclear surface. The “aster” type MT foci gradually gathered to form a bipolar spindle. MTs connecting the spindle pole region and the PPB were seen in late prophase. In CHM-treated cells (11-360 μM for 2 h), “branched” and “cross over” type MT foci were prominent, even in prophase cells with well condensed chromosomes. Neither linkages of MTs between the spindle pole region and the PPB nor “aster” type MT foci were seen. These observations showed that CHM prevents the bundling of MTs in the PPB and also inhibits the formation of “aster” type MT foci that is essential for bipolar spindle development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273249
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  • 5
    Electronic Resource
    Electronic Resource
    Activin and its receptors in the goldfish (1997)
    Springer
    Fish physiology and biochemistry 17 (1997), S. 143-153 
    Details
    ISSN: 1573-5168
    Keywords: goldfish ; activin ; inhibin ; receptors ; perifusion ; immunocytochemistry ; cloning ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Activin (βAβA, βAβB and βBβB) is a dimeric protein that belongs to the transforming growth factor-β (TGF-β) superfamily of growth factors and is involved in the regulation of many physiological and developmental processes. Recently, we have demonstrated that porcine activin stimulated goldfish gonadotropin-II (GTH-II) and growth hormone (GH) secretion from dispersed pituitary cells in static culture and pituitary fragments in perifusion. The action of activin in the goldfish is unique in that it has an acute stimulatory effect on the secretion of GTH-II and GH, whereas in mammals activin usually exhibits long-term stimulatory actions on FSH secretion. The action mechanism of activin is different from that of gonadotropin-releasing hormone (GnRH). Using domain-specific antibodies against mammalian activin subunits, we subsequently demonstrated the existence of immunoreactive activin subunits (βA and βB) in the goldfish ovary, testis, pituitary and brain, suggesting endocrine, paracrine and autocrine roles for activin in the regulation of goldfish reproduction. Both activin βA and βB subunits have been cloned from goldfish genome by polymerase chain reaction (PCR). Using the PCR fragments as probes, we have cloned a full length cDNA coding for activin βB subunit from the goldfish ovary. Both activin βA and βB subunits show high homology to those of other vertebrates with the βB subunit much more conserved (93 and 98% identity with human and zebrafish βB subunit, respectively). The identity of the cloned βB subunit was further confirmed by expression in the Chinese hamster ovary (CHO) cells and detection of the specific activity of activin in the culture medium. The messenger RNA of activin βB subunit is expressed in a variety of goldfish tissues including ovary, testis, brain, pituitary, kidney and liver, suggesting a wide range of physiological roles for activin in the goldfish. We have also cloned a full length cDNA coding for the activin Type IIB receptor from the goldfish ovary, suggesting that activin may have paracrine or autocrine actions on the ovarian functions. The identity of the cloned receptor was confirmed by specific binding of125 I-activin on COS-1 cells transfected with the cloned Type IIB receptor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007718019166
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  • 6
    Electronic Resource
    Electronic Resource
    Sulfation and uptake of the maturation-inducing steroid, 17α,20β-dihydroxy-4-pregnen-3-one by rainbow trout ovarian follicles (1995)
    Springer
    Fish physiology and biochemistry 14 (1995), S. 301-311 
    Details
    ISSN: 1573-5168
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rainbow trout ovarian follicles were incubated in vitro with tritiated 17α,20β-dihydroxy-4-pregnen-3-one (17,20β-P; maturation-inducing steroid). Within 18–24 h, 56–66% had been converted to tritiated 17α,20β-dihydroxy-4-pregnen-3-one 20-sulfate (identification confirmed by HPLC) and 27% had been taken up (absorbed) by the follicles. Addition of 125 ng of cold (non-tritiated) 17,20β-P to the incubations caused a decrease in the percentage of [3H]-17,20β-P which was sulfated (56% → 10%) and an increase in the percentage that was taken up (27% → 57%). Seven steroids were tested for their effectiveness in decreasing the sulfation and increasing the uptake of tritiated [3H]-17,20β-P. The order of effectiveness was in both cases the same: 17,20β-P 〉 cortisol 〉 11-deoxycortisol 〉 17α,20β,21-trihydroxy-4-pregnen-3-one 〉 17α-hydroxy-4-pregnene-3,20-dione 〉 17β-estradiol 〉 testosterone. This indicated that the processes of sulfation and uptake of [3H]-17,20β-P were related to each other and led to the hypothesis that, when cold 17,20β-P is added to the medium, it reduces the proportion of [3H]-17,20β-P which is sulfated and thus allows more free [3H]-17,20β-P to enter the ovarian follicles. This hypothesis was supported by the finding that each ovarian follicle had the capacity in vitro to sulfate only ca. 2 ng of [3H]-17,20β-P per 18h but a capacity to take up 〉 500 ng per 18h. Gonadotropin I, Gonadotropin II, forskolin and phorbol-12-myristate-13-acetate (which all have an affect on steroid biosynthesis) did not affect the amount of 17,20β-P which was sulfated. Sulfating activity was localized in the thecal cell layer of the follicle. The yolk fraction was shown to be responsible for absorbing the [3H]-17,20β-P.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00004068
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  • 7
    Electronic Resource
    Electronic Resource
    Relation between anomaly in type-I superstring and anomaly in its effective theory (1988)
    Springer
    The European physical journal 39 (1988), S. 47-56 
    Details
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We explicitly calculate the hexagon and heptagon (covariant) gauge anomaly including the precise numerical coefficients in type-I open superstring. The calculation is performed by using the Pauli-Villars regularization on the basis of the stringy Ward identity, which is an assumption weaker than the cancelled propagator argument. We show that the anomalies in the effective theory are realized as the zero slope limit (α′→0) of the string anomalies in a very non-trivial way in the present calculational scheme. This non-trivial realization in higher point (n≧8) anomalies is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01560389
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  • 8
    Electronic Resource
    Electronic Resource
    cDNA cloning and functional characterization of a meiosis-specific protein (MNS1) with apparent nuclear association (1994)
    Springer
    Chromosome research 2 (1994), S. 99-113 
    Details
    ISSN: 1573-6849
    Keywords: cDNA cloning ; intermediate filament ; meiosis ; mouse ; nuclear behaviour ; skeletal protein ; spermatogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It is well known that cytoskeleton and karyoskeleton proteins are associated with changes in cell shape and with the rearrangement of the dynamic structures involved in cell division and motility. In higher vertebrates, there are three major skeletal protein groups: microfilaments, microtubules and intermediate filaments, each representing a multigene family. Some of these skeletal proteins are expressed in a temporally- and spatially-specific fashion, and they establish cell-specific cytoplasmic and nucleoplasmic organization during development. Here we report the cDNA cloning of a novel 60 kDa skeletal protein from mouse spermatocytes, termed MNS 1 (meiosis-specific nuclear structural protein), whose computer-predicted protein configuration indicates long α-helical coiled-coil domains flanked by non-helical terminal domains. Functional characterization of MNS1 by ectopic expression in culture cells indicated that it is a detergent-and high salt-resistant skeletal protein which is involved in organization of the nuclear or perinuclear architecture. The MNS1 protein is specifically expressed at the pachytene stage during spermatogenesis, so that its function may involve the determination and maintenance of the appropriate nuclear morphology during meiotic prophase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01553489
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of brain lesions on gonadotrop ultrastructure and serum gonadotropin levels in goldfish (1982)
    Springer
    Cell & tissue research 225 (1982), S. 259-265 
    Details
    ISSN: 1432-0878
    Keywords: Goldfish ; Gonadotropin ; Gonadotrops ; Gonadotropin release-inhibitory factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Brain lesions that destroyed the anterior preoptic region or the pituitary stalk in sexually mature (= completed ovarian recrudescence) goldfish caused a significant increase in serum gonadotropin levels for at least 11 days postoperatively. These results confirmed previous findings indicating the presence of a gonadotropin release-inhibitory factor. Electron-microscopic investigation revealed that the gonadotrops were depleted of the small secretory granules, had marked dilations of the cisternae of the endoplasmic reticulum and extensive development of the Golgi apparatus. This indicated both secretion and synthesis, and correlated with the prolonged increase in serum gonadotropin resulting from the lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214680
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  • 10
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of δ5-3β-hydroxysteroid dehydrogenase in the interrenal cells of the goldfisch (Carassius auratus) (1980)
    Springer
    Cell & tissue research 212 (1980), S. 225-231 
    Details
    ISSN: 1432-0878
    Keywords: Interrenal cells ; Goldfish ; 3β-Hydroxysteroid dehydrogenase ; Ultracytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural localization of the enzyme Δ5-3β-hydroxysteroid dehydrogenase (3β-HSD) was studied in the goldfish interrenal cells by using the potassium ferricyanide method. Immersion fixation in a mixture of 1 % paraformaldehyde and 0.25% glutaraldehyde results in a consistently good ultrastructural preservation and enzyme localization. A precipitate of copper ferrocyanide indicating the localization of 3β-HSD activity was observed in close vicinity to the smooth endoplasmic reticulum or in contact with the outer surface of its membrane. A small number of precipitated grains were also found in the lumen of mitochondrial cristae. Addition of phenazine methosulfate increased the intensity of the reaction without changing the localization of the copper ferrocyanide grains. These findings suggest that the outer surface of the smooth endoplasmic reticulum is the major site of 3β-HSD activity in goldfish interrenal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233957
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