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  • Asian elephant  (2)
  • Tetrahymena  (2)
  • drought  (2)
  • 2-hexanone  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 41 (1985), S. 1593-1594 
    ISSN: 1420-9071
    Keywords: Tetrahymena ; growth studies ; utilization of organic phosphate ; role of phagocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Taking advantage of a synthetic nutrient medium, we have studied which compounds phosphate-starvedTetrahymena thermophila can use as phosphate sources for growth and cell multiplication. Ortho-, trimeta- and α-glycero-phosphate are good sources for both the wild type and a food-vacuoleless mutant; phosphorylcholine is used only by the wild type, and 2-aminoethyl phosphonic acid fails to serve as a phosphate source. Since at least two phosphatases are found in the extracellular fluid these results indicate thatTetrahymena can make use of extracellular digestion of nutrients.
    Type of Medium: Electronic Resource
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  • 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
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  • 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
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 19 (1993), S. 2115-2128 
    ISSN: 1573-1561
    Keywords: Elephas maximus ; Asian elephant ; preovulatory pheromone ; tryptanthrine indolo[2,1-b]-quinazoline-6,12-dione ; novel substance response ; estrus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In their natural ecosystems, the sexes of Asian elephants,Elephas maximus, live separately. For several weeks prior to ovulation, the urine and cervical mucus of female Asian elephants contain extractable chemical agents of low volatility that elicit a high frequency of flehmen responses from bull elephants as an integral part of mating. Subsequent to flehmen responses, male sexual arousal occurs and, if the female is available, mating results. During the course of our project to determine the agent(s) and describe the responses associated with female to male sexual communication, we have identified an unusual compound. This compound, apparently the sole component of the active fraction, was identified by mass, proton nuclear magnetic resonance, ultraviolet/visible, and infrared spectrometries as indolo-[2,1-b] quinazoline-6,12-dione (tryptanthrine). Exhaustive and repetitive bioassays established that pure authentic (synthetic) tryptanthrine was not the compound responsible for the bioresponse. Rather a coeluting minor component, also of low volatility, elicited the male bioresponse.
    Type of Medium: Electronic Resource
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  • 5
    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
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 162 (1992), S. 107-110 
    ISSN: 1432-136X
    Keywords: Synthetic nutrient medium ; Cell multiplication ; Hemin ; Phospholipids ; Tetrahymena
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ciliate Tetrahymena thermophila was grown in a synthetic nutrient medium at various amino acid concentrations. Before the beginning of the experiments the cells were starved for 4 h in a pH buffer. They were inoculated at an initial density of only 250 cells per ml. Under these conditions the cells grew and multiplied at only the two highest amino acid concentrations used. Hemin or phospholipids were found to stimulate cell growth at the lower amino acid concentrations. The mechanism behind this stimulatory effect is unknown, but may be connected with the maintenance of an adequate energy flow under adverse conditions. These additions represent an improvement of the synthetic medium for Tetrahymena.
    Type of Medium: Electronic Resource
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