The hypopharyngeal gland (HPG) of the honeybee worker produces royal jelly (RJ) and has a developmental cycle closely related to the division of labor. In this study, we investigated to compare the HPG acini diameter of differently aged worker bees with high royal jelly producing colony (HRC) or less producing colony (LRC). Additionally, we also evaluated whether the fresh weight of the head is a reliable indicator of the developmental status of HPG. The HRC showed a significantly higher RJ production about two-times as compared with those of the LRC. We measured the HG-diameters on days 1, 3, 6, 9, 12, 15. The microscopic analysis revealed that the acini size of the HRC was significantly larger than the LRC. In addition, the acini diameter of HRC was 15% longer than the LRC on the first day after emerging. It was shown that the fastest development during 3 days which is preparing for nurse the brood. The HPG acini diameters increased in both colonies in a similar fashion until day 12 and then decreased. We also compared the fresh head weight of the experimental colonies, differences were similar to the development of HPG. Therefore, high royal jelly production may have a positive correlation between HPG acini size and the fresh head weight.

The silkworm (Bombyx mori), as an industrial insect, possesses a high economic value. Casual discrimination and accumulated genetic information of silkworm varieties are essential ground for the practical utilization and long-term conservation. In this study, nine available microsatellite loci were successfully genotyped from ~50 silkworm strains preserved in Korea. According to genotyping analysis, we obtained 3 ~ 16 alleles per locus, with an average of 7.4, the observed heterozygosity ranging from 0.04 to 0.98, and the polymorphic information content (PIC) ranging from 0.06 to 0.88, revealing that some loci are highly variable. Among 54 strains 13 strains were casually identified by the presence of 17 strain-specific apomorphic alleles. Furthermore, 30 among remaining strains contained strain-specific allele combinations that are also apomorphic to each strain, allowing us to discriminate each of these from other strains by genotyping of multiple loci. These results collectively suggest that the silkworm microsatellite DNA is actually and potentially important molecular marker for the discrimination of the silkworm strains that are preserved as hundreds in Korea, as more loci are genotyped.

Background : Methicillin-Resistant Staphylococcus aureus (MRSA) is a multidrug-resistant (MDR) strain. Especially, MRSA is developing resistance to available antibacterial agents and causing complications in the treatment of infections related to skin, soft tissue, respiratory, bone, joint, and endovascular disorders. Therefore, antibacterial agent combination therapy appears to be a useful option, particularly in developing countries where antibiotic availability is limited. (+)-Usnic acid (UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. Methods and Results : In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against MRSA. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid (EDTA) was used. In the other hand, Sodium azide (NaN3) was used as inhibitors of ATPase. These results suggest that the antibacterial effect of UA was potentiated by membrane-binding agents and ABC transporter-inhibiting agents, implying that antibacterial activity is associated with damage of the cell wall and inhibition of ATPase function by UA. Conclusion : UA and in combination with EDTA and NaN3 could lead to the development of new combination antibiotics against MRSA infection. The results of this study appear to be promising, and they are expected to enhance the use of natural products as drugs.