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Apps P.J.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry
Naturwissenschaften | Year: 2013

Chemical communication via olfactory semiochemicals plays a central role in the social behaviour and reproduction of mammals, but even after four decades of research, only a few mammal semiochemicals have been chemically characterized. Expectations that mammal chemical signals are coded by quantitative relationships among multiple components have persisted since the earliest studies of mammal semiochemistry, and continue to direct research strategies. Nonetheless, the chemistry of mammal excretions and secretions and the characteristics of those semiochemicals that have been identified show that mammal semiochemicals are as likely to be single compounds as to be mixtures, and are as likely to be coded by the presence and absence of chemical compounds as by their quantities. There is very scant support for the view that mammal semiochemicals code signals as specific ratios between components, and no evidence that they depend on a Gestalt or a chemical image. Of 31 semiochemicals whose chemical composition is known, 15 have a single component and 16 are coded by presence/absence, one may depend on a ratio between two compounds and none of them are chemical images. The expectation that mammal chemical signals have multiple components underpins the use of multivariate statistical analyses of chromatographic data, but the ways in which multivariate statistics are commonly used to search for active mixtures leads to single messenger compounds and signals that are sent by the presence and absence of compounds being overlooked. Research on mammal semiochemicals needs to accommodate the possibility that simple qualitative differences are no less likely than complex quantitative differences to encode chemical signals. © 2013 Springer-Verlag Berlin Heidelberg. Source

Apps P.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry | Mmualefe L.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry | Mmualefe L.,University of Botswana | Jordan N.R.,Botswana Predator Conservation Trust | And 4 more authors.
Biochemical Systematics and Ecology | Year: 2014

The felid-specific urinary odour compound 3-mercapto-3-methylbutanol and its precursors have been found in several felid species in captivity, but its presence in wild felids has not previously been investigated. We analysed the naturally deposited scent marks from three species of wild, free-ranging big cats in Northern Botswana and found 3-mercapto-3-methylbutanol in four samples of leopard urine (N=13), but not in lion urine (N=15) or cheetah urine (N=6). Individual variation in the presence of the tomcat compound in samples from big cats in the wild may reconcile conflicting results from captive cats. © 2013 Elsevier Ltd. Source

Apps P.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry | Mmualefe L.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry | McNutt J.W.,Botswana Predator Conservation Trust
Journal of Chemical Ecology | Year: 2012

Gas chromatography/mass spectrometry was used to identify 103 organic compounds from urine, feces, anal glands, and preputial glands of free-ranging African wild dogs, Lycaon pictus. Aliphatic acids were the dominant class of compound in all materials. In addition to aliphatic acids, urine contained dimethyl sulfone, 1,3-propanediol, benzoic acid, 1-methyl-2,4-imidazolidinedione, and squalene as major components: feces contained indole and cholesterol; and both contained 2-piperidone, phenol, 4-methyl phenol, benzeneacetic acid, and benzenepropanoic acid and other compounds. Anal gland secretion was particularly rich in cholesterol and fatty acids, and preputial gland secretion rich in squalene. A large majority of the identified compounds have been reported from other mammals, including species sympatric with African wild dogs. Eleven of the African wild dog components have not been reported previously from mammals and have not been found in sympatric species; one component, 1-methylimidazole-5-carboxaldehyde has not been reported previously as a natural product. In the chemical profiles of their urine, feces, and anal gland secretion African wild dogs differ markedly from other canids. © 2012 Springer Science+Business Media New York. Source

Apps P.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry | Mmualefe L.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry
Chromatographia | Year: 2011

A simple low-cost cannula assembly that extends the range of applications of standard split-splitless gas chromatography inlets has been constructed and applied in the laboratory. With no other modifications to the inlet, it allows true on-column injections with thin needles, and the use of fused-silica transfer lines and special devices, such as wide bore in-needle traps and sample enrichment probes, while still allowing normal injections by standard microsyringes. © 2011 Springer-Verlag. Source

Apps P.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry | Mmualefe L.,Paul G Allen Family Foundation Laboratory for Wildlife Chemistry
Journal of Chromatography A | Year: 2012

A wide variety of samples that can be analysed by gas chromatography do not lend themselves to the usual preparation of solvent extracts for split-splitless injections, and are best handled by purge and trap or equilibrium headspace sampling. A cryo-focussing, flow switching gas chromatography inlet system that handles different types of sample without the need for hardware changes has been prototyped. It provides excellent repeatability and linearity with liquid injections, purge and trap, and equilibrium headspace samples, in both split and splitless modes. The performance of the system was tested with sub-nanogram quantities of challenging analytes such as free carboxylic acids, alcohols, diols, phenols and aldehydes, and volatiles purged from contaminated soil, mammal faeces, a pesticide formulation, and a spice. Repeatability RSDs for peak areas were consistently below 11% and repeatabilities of retention times below 0.05%, independently of sample type (liquid or gas phase) and nature or quantity of compound. Regression coefficients of peak areas vs. quantity were typically ≥0.999 over two orders of magnitude ranges extending down to below 0.01. ng, also independently of sample and analyte. Limits of quantitation were robustly below 0.1-0.2. ng. Peak shapes and resolution are the same with use of the cryo-trap and flow switch as they are with conventional injections. Performance is robust to flow rate and, for most compounds, to trapping and desorption temperature. The cryo-trapping flow switching inlet's performance parameters match those of other sample introduction systems, and are achieved with sub-nanogram quantities of intractable analytes. © 2012 Elsevier B.V. Source

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