Library

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 1970-1974  (3)
Material
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 90 (1974), S. 275-295 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The hypothesis advanced by James W. Truman to explain the photoperiodically regulated circadian rhythm of adult eclosion in a Saturniid moth has been modified and extended to form the basis of a proposed Developmental Determination Model. This model postulates the synthesis of a hypothetical substance (S) and the kinetics of its metabolism in the presence or absence of light energy. The relationship of scotophase duration to the temporal occurrence of postulated “determination response thresholds” was estimated in the terms of the hypothetical model. The temporal position of a postulated “Determination Gate” was also approximated in terms of the model system. The characteristics of the proposed model were designed to be consistent with the observed effects of different 24-hour photoperiods on the incidence of diapause among larvae of the European corn borer,Ostrinia nubilalis. The proposed Determination Model was shown to be capable of generating all four types of photoperiodic diapause reponse curves reported in existing literature.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 90 (1974), S. 297-310 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A model formulated to provide a theoretical basis for the interpretation of developmental responses to photoperiod is presented. Experimental data on the photoperiodic determination of diapause and non-diapause in the European corn borer,Ostrinia nubilalis, were used to estimate the required characteristics of the model. The prototype model, presented in the previous paper (I) of this series (Beck, 1974) postulated the existence of a photoperiodically regulated time period during which developmental alternatives are determined; this time period was called the Determination Gate (DG). The present study includes determination of the characteristics and kinetics of a model system [the (P)-system] underlying the temporal placement of DG. The effects of photophase duration on subsequent DG placement are also presented.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 148 (1974), S. 287-300 
    ISSN: 1432-0878
    Keywords: Symbiotes ; Aphids ; Antibiotics ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of penicillin and chlortetracyline HCl on the fine structure of the intracellular symbiotes of the pea aphid were studied in an attempt to remove the symbiote population. High penicillin concentrations, 1% and 0.1%, caused symbiote breakdown but were toxic and/or repellent to the aphids; at 0.1% specific effects were observed on the symbiotes' cell walls. After the use of 0.01% penicillin in the aphid diet, the symbiotes had abnormal cell walls and were abnormally dilated; however, symbiote division and transmission from one aphid generation to the next seemed unaffected and the aphids appeared normal. Aphids fed 0.1% chlortetracycline failed to reproduce. After 7 days, their symbiotes were found to break down at a high rate but aphid mitochondria were also adversely affected at this stage. Following 0.002% chlortetracycline, the aphids produced aposymbiotic progeny with apparently normal mitochondrial populations; these larvae failed to develop.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...