The 10th Chemical Signals in Vertebrates meeting was held at the University of Wales Conference Centre at Gregynog Hall in Newtown Powys on the 18th and 19th September. The meeting was opened by Dr Eric Albone (Clifton Trust), the founder of the UK Semiochemistry Network. Eric sketched out a history of the meeting, with its beginnings in Bristol, the resurgence in Kent and the recent move to Wales. The unique cross-disciplinary (eclectic!) nature of the meeting was stressed as one of its strengths.

The BBA guest lecture was given by Dr Allan Kalueff, (Director, Centre for Physiology and Biochemical Research, Kiev, Ukraine) who spoke on Anxiety and Olfaction Disturbances in Animals. This paper dealt with the behavioural and effects of anxiety observed in rodents at different arousal levels. The results indicate that mild arousal might have "paradox" anti-anxiety effects on rodent behaviour while higher arousal level are a pro-anxiety factor, The concept of "pleasurable emotion" produced in rodents by mild arousal is supported [1,2].

Although the primary focus of the workshop is vertebrate semiochemistry, it has always welcomed papers on non-invertebrates. In particular, the enormous volume of literature on insect semiochemistry, inevitably provokes comparison with vertebrates. Dr. Vinay Varshney (Forest Research Institute, Dehra Dun, India) described recent work on the Semiochemical interactions between the sal heartwood borer, Hoplocerambyx spincornis and the host tree, Shorea robusta. Borers of hard wood are comparatively rare and Shorea robusta is a one of the most economically important trees in India. The current practice is to club the trees to allow the bast sap to ooze out. The insects which are attracted by the sap are killed by hand. Current work is directed towards identification of the attractive constituents of the resin, so that they can be incorporated into conventional sticky traps.

Mr. Avinash Jain (Tropical Forest Research Institute, Jabalpur, India).described the Identification of resistant clones of teak Tectone grandis L.f.) through: biological and chemical characteristics. Teak is susceptible to attack by a range of insects, some of which are capable of complete defoliation, however certain strains of teak are resistant to attack. These have been cloned and the chemical basis for resistance is being investigated. High levels of polyphenols, a high ratio of polyphenols to protein and a high ratio of carbohydrates to nitrogen are good indicators of resistance.

Dr Chris Miles (Dept of Psychology, University of Wales, Cardiff) completed the days proceedings with a lecture on Olfactory memory. Recall of a series of odours, follows the well established serial position curve, in which stimuli at the beginning (primacy) and to a lesser extent at the end of the series (recency) are recalled better than those in the middle. Recall of the last odour is suppressed if an extra odour is presented at the end of the sequence (suffix effect) [3]. However an extra stimulus in a different modality (e.g. auditory) does not produce a suffix effect. The results were interpreted in a linear model consisting of a saturatable perception buffer, linked to short-term and long term memory stores.

The ECRO guest lecture was given by Prof Jane Hurst (Dept of Veterinary Science, University of Liverpool) on the Social Odours of Rodents. Over the past few years, it has become increasingly clear that many mammalian pheromone systems consist of a small protein (lipocalin) which binds a volatile ligand. This system can act in one of three ways: the ligand alone has a profound pheromonal effect (i.e. a change in behaviour or physiology, other than simple attraction) and the protein is an inert carrier, both ligand and protein have pheromonal effects or the ligand only acts as an attractant (the pheromone's pheromone!) and the protein causes the pheromonal effect [4]. The 3,4-dehydro-exo-brevicomin/2-sec-butyl-4,5-dihydrothiazole/mouse urinary protein (MUP) system seems to fall into the second category. The volatile ligands cause aggression between males, whereas the protein unblocks puberty delay. Mouse urine was fractionated and as expected the fraction containing urinary proteins with bound ligands stimulated more counter marking and investigation than the control or other fractions. Paradoxically when the behavioural effects of fresh, aged, or menadione treated samples, were compared the latter two elicited the strongest responses, despite containing the lowest levels of ligands. This experiment clearly indicates that the protein rather than the ligand evokes the behavioural response and possibly suggests that the mouse perceives that an aged and uncountermarked mark indicates a stronger territorial claim than a fresh mark. Another major issue raised by this lecture was the significance of the heterogeneity of MUPs [5,6,7].

Dr David Kelly (Dept of Chemistry, University of Wales, Cardiff) discussed the uses of Natural Musks in Perfumery and the chemical analysis of a contraband musk pod and civet. Muscone and civetone are two of the most important classical sources of musk odours for perfumes. Muscone is extracted from musk pods, which are the secretion from the peri-genital gland of the musk deer. Entire herds are killed by netting and shooting to obtain the pods [8]. Civetone is extracted from civet, the secretion of the peri-anal gland of the civet cat. Civet cats are trapped from the wild and kept in appalling conditions to obtain civet. Trade in both products is regulated by CITES (Convention on International Trade in Endangered Species of Wild Flora and Fauna), but there is a flourishing illegal trade in these products and it is rumoured that some of the most expensive perfumes contain natural civetone and musk. The WWF, WSPA and TRAFFIC are engaged in a campaign to uncover illegal use of musk and civet. As part of this work it is essential to be able to discriminate between natural and artificial materials. Artificial civetone is easily identified by GC because it contains cis- and trans-isomers, whereas the natural material is entirely the cis-isomer. Artificial muscone is racemic, whereas the natural material is a single enantiomer, however the enantiomers are extremely difficult to separate.

The meeting finished with a presentation by Jenny Oliver (Dept. of Physical Sciences, University of Kent) on "The Nose Bus" and other experiences of presenting semiochemical phenomena to the public and media. Jenny obtained a Millennium grant for setting up a mobile exhibition of the Sense of Smell in an old red London bus, which visited schools in Kent and the surrounding area. The challenge of producing working interactive exhibits in record time and maintaining them on the move, was accomplished with great skill and dedication.

References

1. On the role of behavioural hyperactivation in anxiety formation in rodents, Kalueff, A. V., Zhurnal Obshchei Biologii, 60: (2) 207-212 Mar-Apr 1999.
2. Eleven urgent questions of anxiety neurobiology, Kalueff, A. V., Neurophysiology, 31: (3) 188-190 May-Jun 1999.
3. Recency and suffix effects with immediate recall of olfactory stimuli, Miles C., Jenkins R., Memory, 8: (3) 195-205 May 2000.
4. When is a butterfly like an elephant?, Kelly, D. R., Chemistry & Biology, (8) 595-602 Aug 1996. Web page.
5. The consequences of inbreeding for recognising competitors, Nevison C. M., Barnard C. J., Beynon R. J., Hurst J. L., Proceedings of the Royal Society of London Series B-Biological Sciences, 67: (1444) 687-694 Apr 7 2000.
6. Unravelling the chemical basis of competitive scent marking in house mice, Humphries RE, Robertson D. H. L., Beynon R. J., Hurst J. L., Animal Behaviour, 58: 1177-1190, Part 6 Dec 1999.
7. Scent marks as reliable signals of the competitive ability of mates, Rich T. J., Hurst J. L., Animal Behaviour, 56: 727-735, Part 3 Sep 1998.
8. On the Scent: Conserving Musk Deer- the uses of Musk and Europe's Role in Its Trade, Homes, V. TRAFFIC Europe, 1999, ISBN 90-9012795-X.