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  • 1
    Electronic Resource
    Electronic Resource
    Nerol: An alarm substance of the stingless bee,Trigona fulviventris (Hymenoptera: Apidae) (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 1167-1181 
    Details
    ISSN: 1573-1561
    Keywords: Alarm substance ; nest defense ; nerol ; mandibular gland ; Hymenoptera ; Apidae ; Meliponinae ; stingless bees ; Trigona fulviventris ; Apiomerus pictipes ; Hemiptera ; Reduviidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Bees of the genusTrigona and subgenusTrigona possess volatile materials in their mandibular glands, used as alarm substances and as marking pheromones. Heads of workers ofTrigona fulviventris were analyzed by gas chromatography-mass spectrometry. The two major volatile components were nerol (∼ 50%), and octyl caproate (∼ 20%). Relative to other substances tested at a Costa Rican nest, treatments containing 20 μg of nerol attractedT. fulviventris, depressed numbers of bees leaving the nest by about 50%, and elicited wing vibration and biting. The responses were similar to those obtained with the contents of one worker head. Attraction and biting were also seen in response to captures of colony members by assassin bugs (Apiomerus pictipes) outside a nest entrance; one bee responded in about 15% of the captures. This alarm behavior, although weak, is of interest since it was thought thatT. fulviventris was unusual for its subgenus in its lack of nest defense behaviors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00990750
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Alarm substances of the stingless bee,Trigona silvestriana (1985)
    Springer
    Journal of chemical ecology 11 (1985), S. 409-416 
    Details
    ISSN: 1573-1561
    Keywords: Alarm substances ; nest defense ; 2-heptanol ; 2-nonanol ; mandibular gland ; Hymenoptera ; Apidae ; Meliponinae ; stingless bees ; Trigona silvestriana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract 2-Nonanol, 2-heptanol, octyl decanoate, and octyl octanoate were identified from the heads ofTrigona silvestriana workers. When presented at the nest, 2-nonanol, 2-heptanol, and the mixture of the four compounds elicited angular flights, landing, and buzzing of guard bees. Octyl octanoate elicited a weaker response. No response was given to octyl decanoate, to the ether solvent, or to the control volatile, vanillin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00989552
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The crater defect in boar spermatozoa: A correlative study with transmission electron microscopy, scanning electron microscopy, and light microscopy (1980)
    New York, NY : Wiley-Blackwell
    Gamete Research 3 (1980), S. 259-266 
    Details
    ISSN: 0148-7280
    Keywords: spermatozoa ; boar ; crater defect ; electron microscopy ; nucleus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Nuclear vacuoles resembling the “crater defect” described in bull spermatozoa were observed in 14 boars. Both the incidence of the defect and semen quality were monitored with phase contrast microscopy over a three-month period. The percentages of cratered spermatozoa varied widely both among boars and in ejaculates from the same boar taken on different days. The presence of cratered spermatozoa at a level of 5% or more appeared to be associated with low semen quality. The defect was studied with scanning and transmission electron microscopy and was found to consist of nuclear invaginations, about 0.5 μm in diameter, containing some scanty amorphous electron-dense material. In boars showing a high incidence of spermatozoa with crater defects, abnormalities of the acrosome and perforatorium were common.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120030308
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    The morphological and ultrastructural appearance of the crater defect in stallion spermatozoa (1985)
    New York, NY : Wiley-Blackwell
    Gamete Research 12 (1985), S. 41-46 
    Details
    ISSN: 0148-7280
    Keywords: spermatozoa ; stallion ; crater defect ; electron microscopy ; nuclear ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The appearance of the nuclear abnormality “crater defect” is described in spermatozoa from the domestic horse (Equadae). Under scanning electron microscopy, the defect appears as a severe depression at any area of the sperm nucleus or as a blister or swelling at some point on the sperm nucleus. Ultrastructurally, the crater appears as a nuclear vacuole containing amorphous material similar to that described in bull and boar sperm. The craters ranged in size from 0.5 to 2 μm in diameter. Within ejaculates of stallions having this defect, the percentages of sperm with crater defects varied widely over time, being as high as 60% and as low as 15%.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120120105
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  • 5
    Electronic Resource
    Electronic Resource
    Attempted sexing of bovine spermatozoa by fractionation on a Percoll density gradient (1988)
    New York, NY : Wiley-Blackwell
    Gamete Research 20 (1988), S. 83-92 
    Details
    ISSN: 0148-7280
    Keywords: spermatozoal ; separation ; flow cytometry ; semen sexing ; electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Bovine spermatozoa were fractionated on Percoll density gradients into two major subpopulations of motile spermatozoa and a minor fraction containing mostly nonmotile spermatozoa with abnormal morphology. Fractionation required the addition of bovine serum albumin and a continuous Percoll gradient buffered with sodium bicarbonate. It is postulated that, under suitable ionic conditions, the binding of bovine serum albumin to spermatozoa amplifies subtle differences between subpopulations. These studies were directed toward separating Y- and X-bearing spermatozoa. However, when the subpopulations were evaluated by flow cytometry, their Y:X ratios were similar to that of an unfractionated control.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120200108
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    Paper (German National Licenses)
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