ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 25 (1994), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. The effects of two synthetic androgens, 17α-methyltestosterone (5–50mg/kg food), 19-nor-ethynyltestosterone (2–50 mg/kg food) and two natural androgens, 11 ketotestosterone (10–60mg/kg food) and androstenedione (20–100mg/kg food) were investigated in the fighting fish, Betta splendens Regan. Androgens were administered for 40 days from the first day of feeding. Masculinization occurred in 100% of individuals fed 8, 15, 60, 90 mg/kg food 19–nor–ET, 17α–MT, 11–KT and AT respectively. Mortality due to treatment of natural steroids was significantly less than that with the synthetic steroids. Sex–reversed males were sexually functional and their genotype was identified by progeny testing. Sex-reversed males produced 100% female monosex when mated with normal females, indicating that the mechanism of sex determination in this fish is homogametic female and heterogametic male.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 21 (1990), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Triploidy was induced in the zebrafish, Brachydanio rerio (Hamilton), by varying all possible combinations of the time after fertilization (AF) (1-3min after insemination), temperature (36-42°C) and shock duration (1-7min). A thermal shock of 41°C for 4min, 2.5min AF ensured 100% triploidy and maximum (51%) survival. Induction of triploidy was confirmed by measurement of erythrocyte nuclear volume and chromosome counting. There was no significant difference in the growth rate of triploid and diploid fishes. All surviving triploids developed into males, and produced a few spermatozoa unable to fertilize normal eggs. A study on thermal and other characteristics required to ensure 100% triploidy rate in fish indicates that these characteristics are species specific.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 25 (1994), S. 0 
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Optimum conditions for hydrostatic pressure treatment for duplication of chromosome set in gynogenetically activated fighting fish, Betta splendens (Regan), eggs were identified. Maximum survival of heterozygous gynogens was 50%, when 2·5-min-old eggs, after insemination with UV irradiated tilapia sperm, were pressure shocked at 7000psi for 6 min. The frequency (21%) of homozygous gynogenetic fry was high, when the 34min (post-insemination) old eggs, which were inseminated with tilapia sperm, were pressure shocked for 5 min. Sex ratio of gynogenetic progeny suggested that the mechanism of sex determination in this fish is homogametic female and heterogametic male.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0148-7280
    Keywords: oocyte ; nuclear migration ; germinal vesicle ; goldfish ; teleost ; Carassius auratus ; meiosis ; steroid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effect of progestogens on nuclear or germinal vesicle dissolution (GVD) was tested in goldfish (Carassius auratus) follicle-enclosed oocytes in vitro. The results indicated the following hierarchy of GVD activity: 17α20β dihydroxy progesterone (DHP) 〉 17α hydroxy progesterone (HP) 〉 progesterone (P). Further studies with DHP indicated that nuclear migration (GVM) preceded GVD, and that no significant GV size changes (ie, diameter in animal-vegetal pole axis) occurred during GVM. The in situ GV visualization technique used (ie, acetic acid yolk clearing with concurrent nuclear precipitation) was verified using standard paraffin sectioning procedures. The two techniques yielded highly correlated results and indicated that GVM is initiated between 12-18 hr, after DHP addition at 15°C. The goldfish oocyte in vitro system as described here is a useful model for the study of hormonally induced GVM and GVD.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...