Separation, identification and bioassay

Evidence has been accumulating that extracellular metabolic activity of microorganisms, mainly bacteria, occurs within skin glands and on the skin surface (Albone, 1997). Sterile human apocrine secretions do not develop the characteristic axillary odour (Shelley et al., 1953). In the salivary secretions of the boar, transformations of the pheromonal 16-androstene steroids 2. were attributed to the microbial flora (Booth, 1987). 

Amongst the secretions of specialised exocrine complexes, the ancillary products which act as sticky compounds are large, often proteinaceous, molecules. Their primary, secondary and tertiary structures being inherently complex are now seen as ideal informational vehicles — alone or in combination with volatile molecules. Much recent work (Sec. 3.2, below) has identified them as the key components involved in close range transmission, and in intra-nasal peri-receptor events. Proteins are semiochemically implicated when their selective removal or presentation alters responsiveness (Belcher et al., 1990 Mucignat-Caretta et al, 1995). 

IB Mouse chemosignal complex, ligand + urinary protein location of 2-jeobutyl-4,5-dih yd rot hi azole (DHT) within the binding pocket at the N-terminus (lower) in MUP (from Tirindelli et ai, 1998). 

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