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Vertebrate pheromones and other semiochemicals: the potential for accommodating complexity in signalling by volatile compounds for vertebrate management.

Pickett JA, Barasa S, Birkett MA - Biochem. Soc. Trans. (2014)

Bottom Line: Aggravating this is the complexity of the mixtures involved with pheromones, not only by definition associated with each species, but also with individual members of that species and their positions within their immediate communities.Nonetheless, already in some contexts, particularly where signals are perceived at other trophic levels from those of the vertebrates, e.g. by arthropods, reductionist approaches can be applied whereby the integrity of complex volatile mixtures is maintained, but perturbed by augmentation with individual components.In the present article, this is illustrated for cattle husbandry, fish farming and human health.

View Article: PubMed Central - PubMed

Affiliation: *Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, U.K.

ABSTRACT
The interaction between volatile and non-volatile, e.g. proteinaceous, components of pheromone and other semiochemical-based signalling systems presents a daunting set of problems for exploitation in the management of vertebrates, good or bad. Aggravating this is the complexity of the mixtures involved with pheromones, not only by definition associated with each species, but also with individual members of that species and their positions within their immediate communities. Nonetheless, already in some contexts, particularly where signals are perceived at other trophic levels from those of the vertebrates, e.g. by arthropods, reductionist approaches can be applied whereby the integrity of complex volatile mixtures is maintained, but perturbed by augmentation with individual components. In the present article, this is illustrated for cattle husbandry, fish farming and human health. So far, crude formulations have been used to imitate volatile semiochemical interactions with non-volatile components, but new approaches must be developed to accommodate more sophisticated interactions and not least the activities of the non-volatile, particularly proteinaceous components, currently being deduced.

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Proposed biosynthesis of the mouse volatile compound SBT
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Figure 2: Proposed biosynthesis of the mouse volatile compound SBT

Mentions: Attractant semiochemicals act as signals perceived by the sensory system and without physiological effects, and cause oriented movement towards the origin. Arising from food or food baits, this is an obvious process and has been exploited already for rodents. However, many other aspects of rodent ecology offer the potential for capturing semiochemicals that relate to positive behaviours inducing attraction. For the mouse, Figure 1 shows potentially positively acting volatile semiochemicals associated with mouse urine. The specific roles are complicated by contextual issues relating to sex and hierarchical positions within the mouse community [6]. The biosynthesis of these compounds represents a number of biosynthetic pathways that must relate to mouse genetics, so far mostly not annotated in the mouse genome [7], with identification likely to be facilitated via the transcriptome [e.g. NGS (next-generation sequencing) or RNA-Seq (RNA sequencing)] associated with the presence of these compounds in the urine. For SBT [(S)-2-sec-butyl-4,5-dihydrothiazole], the proposed route involving oxidation of isoleucine before cysteine conjugation can be presumed to involve a cytochrome P450 enzyme (Figure 2). Other positively acting semiochemicals are associated with the body of the mouse, but may have their origins in exocrine secretions from various organs, e.g. those associated with mucus-producing regions [8]. Although it is by no means clear how the known compounds could be used in pull systems for mice with much new work needing to be done, such semiochemicals are already being used routinely for arthropod control, e.g. the tsetse fly Glossina morsitans, the vector of Trypanosoma brucei, which is the causative agent of nagana in cattle in Africa, is pulled into traps baited with host urine from the buffalo Syncerus kafir and acetone, a component of host breath. The traps incorporate blue textile, and destruction of the flies is by desiccation or control using black material impregnated with the Rothamsted-invented pyrethroid deltamethrin [9]. The urine itself, as an alternative source of semiochemicals, is appropriate for input-limited farmers and pastoralists, but a completely chemical host lure (POCA) is available comprising 3-n-propylphenol, 1-octen-3-ol, 4-methylphenol (p-cresol) and acetone [10]. This approach is currently being developed for control of other tsetse flies, e.g. Glossina palpalis, that are vectors for trypanosomes causing HAT (human African trypanosomiasis) [11], but more specific host cues may need to be identified and the component 1-octen-3-ol provided as a single isomer as for attraction of Culicoides spp. biting midges [12].


Vertebrate pheromones and other semiochemicals: the potential for accommodating complexity in signalling by volatile compounds for vertebrate management.

Pickett JA, Barasa S, Birkett MA - Biochem. Soc. Trans. (2014)

Proposed biosynthesis of the mouse volatile compound SBT
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128645&req=5

Figure 2: Proposed biosynthesis of the mouse volatile compound SBT
Mentions: Attractant semiochemicals act as signals perceived by the sensory system and without physiological effects, and cause oriented movement towards the origin. Arising from food or food baits, this is an obvious process and has been exploited already for rodents. However, many other aspects of rodent ecology offer the potential for capturing semiochemicals that relate to positive behaviours inducing attraction. For the mouse, Figure 1 shows potentially positively acting volatile semiochemicals associated with mouse urine. The specific roles are complicated by contextual issues relating to sex and hierarchical positions within the mouse community [6]. The biosynthesis of these compounds represents a number of biosynthetic pathways that must relate to mouse genetics, so far mostly not annotated in the mouse genome [7], with identification likely to be facilitated via the transcriptome [e.g. NGS (next-generation sequencing) or RNA-Seq (RNA sequencing)] associated with the presence of these compounds in the urine. For SBT [(S)-2-sec-butyl-4,5-dihydrothiazole], the proposed route involving oxidation of isoleucine before cysteine conjugation can be presumed to involve a cytochrome P450 enzyme (Figure 2). Other positively acting semiochemicals are associated with the body of the mouse, but may have their origins in exocrine secretions from various organs, e.g. those associated with mucus-producing regions [8]. Although it is by no means clear how the known compounds could be used in pull systems for mice with much new work needing to be done, such semiochemicals are already being used routinely for arthropod control, e.g. the tsetse fly Glossina morsitans, the vector of Trypanosoma brucei, which is the causative agent of nagana in cattle in Africa, is pulled into traps baited with host urine from the buffalo Syncerus kafir and acetone, a component of host breath. The traps incorporate blue textile, and destruction of the flies is by desiccation or control using black material impregnated with the Rothamsted-invented pyrethroid deltamethrin [9]. The urine itself, as an alternative source of semiochemicals, is appropriate for input-limited farmers and pastoralists, but a completely chemical host lure (POCA) is available comprising 3-n-propylphenol, 1-octen-3-ol, 4-methylphenol (p-cresol) and acetone [10]. This approach is currently being developed for control of other tsetse flies, e.g. Glossina palpalis, that are vectors for trypanosomes causing HAT (human African trypanosomiasis) [11], but more specific host cues may need to be identified and the component 1-octen-3-ol provided as a single isomer as for attraction of Culicoides spp. biting midges [12].

Bottom Line: Aggravating this is the complexity of the mixtures involved with pheromones, not only by definition associated with each species, but also with individual members of that species and their positions within their immediate communities.Nonetheless, already in some contexts, particularly where signals are perceived at other trophic levels from those of the vertebrates, e.g. by arthropods, reductionist approaches can be applied whereby the integrity of complex volatile mixtures is maintained, but perturbed by augmentation with individual components.In the present article, this is illustrated for cattle husbandry, fish farming and human health.

View Article: PubMed Central - PubMed

Affiliation: *Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, U.K.

ABSTRACT
The interaction between volatile and non-volatile, e.g. proteinaceous, components of pheromone and other semiochemical-based signalling systems presents a daunting set of problems for exploitation in the management of vertebrates, good or bad. Aggravating this is the complexity of the mixtures involved with pheromones, not only by definition associated with each species, but also with individual members of that species and their positions within their immediate communities. Nonetheless, already in some contexts, particularly where signals are perceived at other trophic levels from those of the vertebrates, e.g. by arthropods, reductionist approaches can be applied whereby the integrity of complex volatile mixtures is maintained, but perturbed by augmentation with individual components. In the present article, this is illustrated for cattle husbandry, fish farming and human health. So far, crude formulations have been used to imitate volatile semiochemical interactions with non-volatile components, but new approaches must be developed to accommodate more sophisticated interactions and not least the activities of the non-volatile, particularly proteinaceous components, currently being deduced.

Show MeSH