Chapters in Books (Chemistry and Polymer Science)

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    Neonatal recognition in sheep
    (Springer New York, 2013) Burger, B. V.; Viviers, Marlize Z.; Le Roux, Niel J.; Morris, John; Bekker, Jan P. I.; Le Roux, Maritha
    The strong bond formed between ewe and lamb shortly after parturition is an important factor in lamb survival. Evidence exists that the ewe can distinguish her lamb by its unique smell, but the constituents of such a putative pheromone have not yet been identified. We have identified 133 volatile organic compounds in the cranial wool of Dohne Merino lambs that are presumably constituents of the neonatal recognition cue of this sheep race. Quantitative analysis and comparison of the odour profiles of the twins of 16 ewes of a flock of 165 twin-bearing ewes (9 .69% sample group) revealed that the wool volatiles of twins are qualitatively as well as quantitatively practically identical, but differ from those of other twins or non-twin lambs in the flock. The 88 constituents present in at least 20% of the analysed wool samples were considered as variables for multivariate analysis. A ?-value <0.0001 was calculated, indicating that the pairing of twins according to the qualitative and quantitative composition of the wool is statistically highly significant. Bioassays carried out during the lambing seasons of 2009 and 2010 confirmed the previously established role of the odour of lambs in ewe-lamb recognition. However, ewes rejected alien lambs dressed in jackets that were sprayed with mixtures formulated with synthetic analogues of the identified wool volatiles according to the qualitative and quantitative compositions of the experimental ewes' own lambs. This is probably due to the volatiles not being released into the atmosphere in quantitative ratios emulating the odour of the lambs accurately enough to satisfy the experimental ewes.
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    Capillary gas chromatography in the identification of semiochemicals
    (InCom publishers, 1997) Burger, B. V.
    The role of gas chromatography and its ancillary techniques in the identification of pheromones and other semiochemicals over the last 30 years is discussed, using some examples from research on chemical communication in insects and mammals.
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    Olfactory ecology
    (Wiley-Blackwell, 2011) Tribe, G. D.; Burger, B. V.; Simmons, Leigh. W.; Ridsdill-Smith, T. James
    INTRODUCTION: As the morning sky over Zululand begins to lighten, and before the intense heat of the sun's rays breaks through the morning mist, the air is filled with the sound of flying dung beetles as they begin to search for dung voided during the night. As the day progresses, waves of dung beetles arrive at the rhino middens, which eventually teem with hundreds of beetles of many species. Out of this melee, several dung beetles are seen rolling away balls of dung to which a female clings. But how do the beetles find ephemeral and patchy dung resources - and, when they arrive at the dung, how do they find conspecific mates?
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    Mass spectrometry in pheromone research
    (Elsevier, 2005) Burger, B. V.; Nibbering, Nico M.
    INTRODUCTION: The application of mass spectral techniques in the identifica tion of compounds invo lved in chemical communication between living organisms will be discussed in this a rticle. These biologically highly active chemical compounds are lumped together under the term " se miochemicals" from the Greek Sl!mion , a sign. Depending on the relationship between the producer and receiver of a chemical message, various other terms, such as pheromones, allomones, and kairomones, are also used to define these compounds or mixtures of compounds. An allomone, for example, could thus be a single compound or a mixture of compounds that together elicit a specific reaction in the target organism.
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    Mammalian semiochemicals
    (Springer Berlin Heidelberg, 2005) Burger, B. V.; Schulz, Stefan
    Progress that has been made in research on the chemical aspects of mammalian semiochemistry over the past decade is discussed on the basis of examples from the most topical problem areas. The chemical characterization of the volatile organic constituents of the urine, anal gland secretions and exocrine gland secretions of rodents, carnivores, proboscids, artiodactyls and primates, and their possible role in the semiochemical communication of these mammals are discussed, with particular emphasis on the advances made in the elaboration of the function of proteins as controlled release carrier materials for the semiochemicals of some of these animals.