| 10-HDA (10-hydroxy-2-decenoic acid ,10-HDA) is an very important quality component of royal jelly. The mandibular glands of honeybee workers are the only gland for secretion of 10-HDA, It also secreted a pheromone as 2-heptanone. In recent years, researches were more concerned about the queen mandibular glands or its pheromones, However, the metabolic mechanism of 10-HDA synthesis in mandibualr glands of the workers is unclear yet. Our aim is to find related proteins in 10-HDA synthesis. The study compared the differences of 10-HDA secreted and gland proteins of Apis mellierea ligustica worker at different ages.The content of 10-HDA in the mandibular glands of workers of different age were measured by RP-HPLC. The results showed that 10-HDA of newly hatched Italian honeybee workers was very low, only 7.03±2.98μg/bee, That of 5-day-old workers from colonies producing royal jelly was 26.14±6.38μg/bee, significantly higher than the former (p<0.01) . That of 10-day-old workers was 45.52±6.88μg/bee, significantly higher than that of 5-day-old group (p<0.01). There were no significant differences among those of 15-day-old, 20-day-old and 25-day-old (p>0.05). 10-HDA contents of 30-day-old workers were significantly increased up to 56.32±15.81μg/bee (p<0.01). 10-HDA in the glands of 5-day-old workers from colonies non producing royal jelly was 36.67±3.44μg/bee, about 10μg/bee higher than that from colonies producing royal jelly, the difference was significant (p<0.0001). 10-HDA of 10-day-old worker was significantly increased (p<0.01), up to 43.57±7.93μg/bee, and there was no significant difference between groups of royal jelly producing and non-producing (p>0.05). There were no significant differences among 10-, 15-, 20-day-old workers within the non-producing groups (p>0.05). Compared with producing groups, there were no significant differences at 10-, 15-day old (p>0.05), however, the significant differences were do showed both at 20-day-old (p<0.05) and 25-day-old (p<0.01), 10-HDA of 25-day-old workers was 67.62±11.89μg/bee that was highest within non-producing groups.Immobilized two-dimensional electrophoresis was used to compare the differences of mandibular gland proteins of newly hatched, 5-, 10-day-old workers. The results showed, that the mandibular glands proteins of newly hatched bee were the most, The number of proteins expressed in different quantity is up to 111 between newly hatched and 5-day-old workers, of which 44 proteins in newly hatched workers were expressed twice higher than 5-day-olds, 67 proteins were down expressed twice, the significant expressive differences of the mandibular gland proteins were related to the changes of gland physiological function. As showed at above results the functional difference between mandibular glands of newly hatched workers and 5–day-old workers was mostly concerned about the fatty acids synthesis mainly of 10-HDA, therefore, we suggested that the protein differences was primarily related to 10-HDA and related fatty acids synthesis. There were five proteins expressed gradually higher from newly hatfched to 5-, and 10-day-old workers, of which SSP4005 (Mr = 21.6kD, pI = 5.90) was expressed at highest level. No qualitative differences were found between 5-day-old and 10-day-old mandibular gland proteins, but there were differences in quantitative level, it means that after 5-day-old the protein expression of the mandibular gland primarily changed in quantitative level to increase the synthesis of 10-HDA, these results were very useful for further search of the key proteins in the synthesis of 10-HDA .
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