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
Filter
  • Electron microscopy  (2)
  • Mongolian gerbil  (2)
  • Pissodes strobi  (2)
  • Springer  (6)
  • American Geophysical Union (AGU)
  • 1975-1979  (6)
Collection
Publisher
  • Springer  (6)
  • American Geophysical Union (AGU)
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 3 (1977), S. 377-389 
    ISSN: 1573-1561
    Keywords: Pissodes strobi ; ecotype ; phytophagy ; speciation ; host selection ; feeding bioassay ; weevil ; dispersal ; chemoreception ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In forced feeding bioassays,Pissodes strobi reared from eastern white pine, Engelmann spruce, or Sitka spruce failed to discriminate between these three host species. However, results of choice feeding bioassays suggest that eastern white pine is the ancestral host of the two westernP. strobi populations. Comparative feeding data obtained under conditions of choice support the hypothesis thatP. strobi has dispersed westward across the North American continent, adapting its host selection behavior in turn to Engelmann spruce and then Sitka spruce. WhereasP. strobi reared from eastern white pine preferred to feed on its natural host rather than on the two western spruces,P. strobi reared from Engelmann spruce did not discriminate between eastern white pine and its natural host, Engelmann spruce, but fed significantly more on these two hosts than on Sitka spruce.P. strobi reared from Sitka spruce, on the other hand, fed equally on all three native host species. Our data support the contention of Smith and Sugden (1969) that the two western weevils are eco types ofP. strobi. Comprehensive research on behavioral adaptations to new host species may allow the threeP. strobi populations to be distinguished as legitimate ethospecies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 4 (1978), S. 641-647 
    ISSN: 1573-1561
    Keywords: Pissodes strobi ; weevil ; host selection ; phytophagy ; oviposition ; chemoreception
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Forced and choice feeding and oviposition experiments were conducted by caging overwinteredPissodes strobi on lateral branches or leaders of sympatric Engelmann spruce and/or western white pine trees in Manning Provincial Park, British Columbia, or on transplanted, potted trees in Burnaby, British Columbia. Whereas femaleP. strobi preferred to feed on 1-year-old Engelmann spruce lateral branches in both the forced- and choice-feeding experiments, male weevils failed to discriminate between this host and western white pine. Forced-feeding experiments that utilized 1-year-old leaders demonstrated that western white pine is an acceptable host forP. strobi feeding, but that the native host, Engelmann spruce, is preferred under choice conditions. In all experiments, female weevils oviposited only on Engelmann spruce. These results indicate that the releasing stimulus for feeding is present in the bark of both conifer species and suggests that a separate releasing stimulus for oviposition is absent from western white pine.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 158 (1975), S. 241-249 
    ISSN: 1432-0878
    Keywords: Synapse development ; Spinal cord ; Foetal rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies on the foetal rat spinal cord show that during synaptogenesis there is difficulty in recognizing true synaptic precursors. Asymmetric densities are found at unusual sites forming, for example, somato-dendritic and somato-somatic junctions. They are also found between neurons and possible glial processes. Symmetric densities occur between nerve cells but may be confused with desmosomes. Profiles exhibiting membrane density, cleft material and 50 nm vesicles, which are the most reliable indicators of presumptive synapses, are found between neurones, but also at junctions between neurones and what may be glial processes. The picture is further confused by the presence of degenerating axodendritic synapses at early foetal stages. Caution must be exercised in defining an apparent synapse or precursor in foetal cord as that of a presumptive functional synapse because of the observed degenerating profiles and because to our knowledge, somato-somatic, somatodendritic, and neurono-glial synapses have not been observed in adult cord. It is not known whether these structures are an unwanted consequence of development or play a role in guiding development.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-0878
    Keywords: Muscle ; Diabetes mellitus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of fast-twitch-oxidative-glycolytic (FOG), fasttwitch-glycolytic (FG) and slow-twitch-oxidative (SO) fibers in plantaris and soleus muscles of normal and streptozotocin-diabetic rats was studied. In the diabetic animals, the mitochondria of FOG and SO fibers showed a loss of cristae and an increase in electron-dense granules. There was also an increased number of lipid droplets in close proximity to the mitochondria and the nuclei, and a separation of individual muscle nuclei to form satellite cells. Higher incidences of surface projections and sarcoplasmic splittings at the nuclear region were noticed in SO fibers. The FG fibers showed some disorientation of the T-tubular system. It is concluded that streptozotocin-diabetes has differential effects on the fine structure of the three fiber types of rat skeletal muscle.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-0878
    Keywords: Epithalamus ; Smpathectomy ; Monoamines ; Fluorescence histochemistry ; Mongolian gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Extirpation of the superior cervical ganglion was performed in a series of Mongolian gerbils. One or two weeks after the ganglionectomy the animals were injected with a monoamine oxidase inhibitor. Subsequently perfusion fixation was performed using the glyoxylic acid-paraformal-dehydemagnesium method (Lorén et al., 1976) for fluorescence histochemical investigation of the monoamines of the pineal complex. In the ganglionectomized animals all of the blue-fluorescent sympathetic fibers in the pineal complex (superficial pineal gland, deep pineal gland and the pineal stalk) completely disappeared. The yellow indolamine fluorescence of the cells in the superficial pineal and the deep pineal, as well as in the pineal stalk, was markedly reduced after ganglionectomy. No change in the morphology or number of sympathetic fibers in the medial habenular nucleus was observed. These results indicate that the presence of sympathetic nerve fibers with perikarya in the superior cervical ganglion is necessary for maintaining a high indolamine content in all three parts of the pineal complex. In addition, the results also indicate that the deep pineal gland is a functional part of the pineal complex. The presence of a functionally active deep pineal, bordering the pineal recess, suggests that part of the pineal hormones might be secreted into the cerebrospinal fluid.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 187 (1978), S. 235-250 
    ISSN: 1432-0878
    Keywords: Innervation ; Fluorescence microscopy ; Pineal organ ; Mongolian gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the pineal gland in the Mongolian gerbil, Meriones unguiculatus, was investigated light microscopically by the Falck-Hillarp fluorescence technique and by conventional light microscopy. The pineal gland displayed a superficial portion just beneath the confluens sinuum and a deep part (lamina intercalaris) connected by a slender pineal stalk, which contained pinealocytes. The superficial part of the pineal gland consisted of dark-stained pinealocytes arranged in lobules, and separated by interstitial cells and connective tissue spaces. Many larger chromophobe cells were scattered throughout this region. A heavy catecholaminergic innervation of the superficial portion of the pineal organ, probably via the conarian nerve, with green fluorescent nerve fibres showing excitation/emission maxima of 415/475 nm was observed. Green fluorescent nerve fibres were also observed in the pineal stalk, from where some fibres turned rostrally indicating a nervous connection between the brain and the pineal organ. The pinealocytes showed a yellow fluorescence displaying a broad excitation curve with a maximum of 380–430 nm and an emission maximum at 505 nm. This indicates the presence of both serotonin and a catecholamine in the pinealocytes. Yellow fluorescence of the cells in the lamina intercalaris was also observed.
    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...