Li Jianjun,Wang Zhengwei,Tan Ken,Qu Yufeng,Nieh James C.
Social pollinators such as honey bees face attacks from predators not only at the nest, but also during foraging. Pollinating honey bees can therefore release alarm pheromones that deter conspecifics from visiting dangerous inflorescences. However, the effect of alarm pheromone and its chemical components upon bee avoidance of dangerous food sources remains unclear. We tested the responses of giant honey bee foragers, Apis dorsata , presented with alarm pheromone at a floral array. Foragers investigated the inflorescence with natural alarm pheromone, but 3.3-fold more foragers preferred to land on the ‘safe’ inflorescence without alarm pheromone. Using gas chromatography–mass spectrometry analysis, we identified eight chemical components in the alarm pheromone, of which three components (1-octanol, decanal and gamma-octanoic lactone) have not previously been reported in this species. We bioassayed six major compounds and found that a synthetic mixture of these compounds elicited behaviors statistically indistinguishable from responses to natural alarm pheromone. By testing each compound separately, we show that gamma-octanoic lactone, isopentyl acetate and (E)-2-decen-1-yl acetate are active compounds that elicit significant alarm responses. Gamma-octanoic lactone elicited the strongest response to a single compound and has not been previously reported in honey bee alarm pheromone. Isopentyl acetate is widely found in the alarm pheromones of sympatric Asian honey bee species, and thus alarmed A. dorsata foragers may produce information useful for conspecifics and heterospecifics, thereby broadening the effects of alarm information on plant pollination.
Isobaric vapor–liquid equilibrium (VLE) data for binary systems of isoamyl alcohol + dimethyl sulfoxide (DMSO) and isoamyl acetate + DMSO, and the ternary system of isoamyl alcohol+ isoamyl acetate + DMSO at 101.33 kPa were measured by a modified Rose-Williams equilibrium still. The binary experimental data were checked by Herington method and a Van Ness test to verified thermodynamic consistency. The ternary VLE data was checked by Van Ness test. The experimental measurements of the binary systems were correlated by Wilson, nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) activity coefficient models with minor deviation. The ternary VLE data predicted by the obtained correlation parameters fit well with the experimental data. The experimental results indicate that the relative volatility between isoamyl alcohol and isoamyl acetate is changed obviously with the addition of DMSO as an entrainer at 0.50 mass fraction, which shows DMSO is an effective solvent for the separation of isoamyl alcohol and isoamyl acetate mixture in extractive distillation.
In this study, a novel lipase M5 derived from Aspergillus oryzae WZ007 was prone to exhibit high hydrolytic activity and stereoselectivity towards racemic substrate ( R , S )-ethyl 2-bromoisovalerate. ( R )-ethyl 2-bromoisovalerate was obtained by enzymatic resolution, which is the key chiral intermediate for highly efficient enantiomerically fluvalinate. The results showed that the enzymatic reaction was carried out in 120mM racemic substrate for 3 hours, the enantiomeric excess reached 98.6%, the conversion was 51.7%, and E value above 120. Therefore, the novel lipase M5 has the ability to efficiently produce ( R )-ethyl 2-bromoisovalerate, which greatly reduces the industrial production cost of the highly efficient counterpart of fluvalinate.
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