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
  • drought  (2)
  • 2-hexanone  (1)
  • 2-nonanone  (1)
  • African elephant  (1)
  • 1
    ISSN: 1573-1561
    Keywords: Temporal gland secretions ; testosterone ; dihydrotestosterone ; Elephas maximus ; volatiles ; elephant ; benzoic acid ; 2-nonanone ; 5-nonanone ; 5-nonanol ; tetradecanoic acid ; decanoic acid ; (E)-farnesol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The temporal glands, modified facial apocrine sweat glands unique to elephants, release collectable secretions during an unusual physiological state termed “musth” in the Asian bull elephant (Elephas maximus). Recently we began the characterization of the chemical components of musth, especially in the temporal gland secretions (TGS), and the examination of the role of such secretions as agents for chemical communication between elephants. The present study focuses on possible correlations between testosterone levels in the serum and temporal gland secretions. We were especially interested in possible qualitative and/or quantitative changes in volatile compounds as the testosterone levels varied during a discrete musth period. Quantitative changes in TGS and serum testosterone were determined by radioimmunoassay. Qualitative and semiquantitative changes occurring in volatile composition were studied by high-resolution gas chromatography (fused silica capillary column, on column injection). Compound identification was by nuclear magnetic resonance, gas chromatography-mass spectrometry, and gas chromatography internal standards. Twenty-three major compounds and a number of minor components were identified. Androgen concentrations were correlated with TGS-specific volatiles including benzoic acid, 2-nonanone, 5-nonanol, tetradecanoic acid, and decanoic acid. The latter two compounds and (E)-farnesol, a major component of African TGS, demonstrated an inverse relationship to T levels.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-5036
    Keywords: drought ; irrigation ; fertilizer application ; nutrients ; Picea abies ; tree growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Water and nutrient supply to forest trees are major factors controlling tree growth and forest vitality. Therefore, changes in the supply of water and nutrients to the trees may be important contributing reasons to the forest damages observed in Europe. Such changes may be caused by several factors, e.g. air pollution, soil acidification and climate change. The present study investigates possible effects on tree growth, growth related parameters and nutrition related to changes in the water and nutrient supply. Water and nutrient supply to the forest soil was manipulated in three roof covered plots. The treatments consisted of 1) summer drought, 2) irrigation and 3) combined irrigation and fertilizer application (fertigation). The results from the roof covered treatment plots were compared to a control plot without roof. Increased supply of water during the spring and early summer increased the diameter growth, whereas application of nutrients in addition to irrigation had no additional effect on tree growth. Addition of nutrients increased the needle content of P, Mn, Ca and Mg. Extended summer drought for 2 months had no effect on the tree growth or other growth parameters, but drought reduced the root development in the upper soil layer. Furthermore, drought induced significant stress symptoms by increasing the cone shredding substantially.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-5036
    Keywords: drought ; nutrient cycling ; potassium ; soil solution ; spatial variability ; throughfall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract At Klosterhede, Denmark experimental manipulations of water and nutrient inputs to a forest stand were carried out under a 1200 m2 roof simulating i) summer drought, ii) removal of N and S input, and iii) optimal nutrition and water availability. In practise, manipulation of element fluxes in a complex system like a forest may cause unintended changes such as climatic effects from the roof which may interfere with the results of the intended manipulation. This paper illustrates the extent and effects of such unintended changes. The most important climatic change under the roof was a 50% reduction of photosynthetic light which caused a decrease in moss cover on the ground floor. Soil temperatures under the roof were decreased 0.3°C during summer and increased 0.2°C during winter. Air humidity was not changed. Throughfall water amount decreased close to the stems whereas element concentrations in throughfall increased close to the stems and with tree size on the ambient plots. This distinct spatial pattern was changed under the roof to a more variable water distribution from the sprinkling system and to constant element concentrations in the sprinkling water. This loss/change of spatial variability in the input was reflected in the soil solution. The concentration patterns found in soil water (increasing close to the stem and with tree size) in the ambient plots were no longer observed under the roof. Exclusion of throughfall by the roof disturbed the internal cycle of nutrients leached from the canopy. The removal of canopy leached Ca and K by the roof caused a decline in soil water concentrations, even on the drought plot where natural throughfall was only cut off during two summer months. The internal cycle of Ca and K had to be restored by addition of Ca and K under the roof. Further, leachable elements and soluble compounds may be washed out from litterfall during the collection period on the roof, and thus lost from the internal cycle by by exclusion of throughfall. It is important to consider these problems in the design of new manipulation experiments and in the interpretation of the results. Some recommendations are given.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-1561
    Keywords: Chemosignal ; pheromone ; Asian elephant ; Elephas maximus ; temporal gland secretion ; musth ; avoiding reactions ; headspace analysis ; 2-hexanone ; 3-pentanone ; 1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A procedure for headspace sampling and long-term storage of organic volatiles coupled with gas chromatographic-mass spectrometric (GC-MS) analysis was used to study the volatile chemosignals in a biological secretion prior to bioassay. The approach involved collecting the volatiles in evacuated canisters from an apparatus in which 1 ml of secretion was dispersed for headspace sampling. These canisters, stainless steel, 850 ml, and 100% internally electropolished, have been demonstrated to store volatile compounds, in chemically stable form, for several weeks. The GC-MS analyses provided the quantitation and identification of compounds from C3 through C14 at concentrations as low as 0.10 parts per billion volume. The approach was used to study chemosignals of musth temporal gland secretions (TGS) from a male Asian elephant (Elephas maximus). Fresh TGS material loses its biological activity within 1 hr. TGS material stored at −20°C usually looses its activity within 30 days. The usefulness of this method for long-term storage of the volatile chemosignals was demonstrated by the retention of biologically active TGS headspace compounds, as determined through bioassays, stored in these canisters for one year.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-1561
    Keywords: African elephant ; Loxodonta africana ; temporal gland secretion ; farnesol ; sesquiterpenes ; phenol ; cresol ; cholesterol ; proteins ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Temporal gland secretion (TGS), obtained from 15 different mature African elephants in Kruger National Park was analyzed for volatile constituents. Only five volatile components were present.p-Cresol was present in all samples, but phenol was found as an appreciable component of only one sample and as trace amounts in six others. Three sesquiterpenes were identified, the latter two being new natural products:E-farnesol, farnesol hydrate (3,7,11-trimethyl-2,10-dodecadien-1,7-diol), and farnesol dihydrate (3,7,11-trimethyl-2-dodecen-1,7,11-triol). These sesquiterpenes represent the first isolated from mammals. Ten samples of TGS, serum, and saliva were assayed for cholesterol, urea, and proteins including several enzymes.
    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...