The black soldier fly (BSF), Hermetia illucens, is known as a beneficial insect and feeds on organic materials derived from animals and human, resulting in reduction of food waste and conversion of organic materials. Despite of many studies on the BSF, there have been no reports of cloned genes encoding serine proteases in the BSF. Thus, the primary objective of this study is to clone and to investigate expression pattern of genes encoding serine proteases released from the midgut of the BSF larvae in order to gain a better understanding of expression mechanism of serine proteases. We cloned two serine proteases from the BSF larva. Based on phylogenetic tree analysis, one was chymotrypsin, the other was trypsin. The open reading frame (ORF) of chymotrypsin was 804bp, which encoded a polypeptide of 267 amino acids. In case of trypsin, the ORF was 744bp, which encoded a polypeptide of 247 amino acids. To investigate expression pattern of two serine proteases, we conducted semi-quantitative RT-PCR at different tissues and different developmental stages. A chymotrypsin and trypsin transcripts were revealed strongly in mid gut. Especially, a chymotrypsin was detected largely at feeding stage more than molting stage, while trypsin was expressed similarly between feeding stage and molting stage

The black soldier fly (BSF), Hermetia illucens, is known as a beneficial insect and feeds on organic materials derived from animals and human, resulting in reduction of food waste and conversion of organic materials. Despite of a lot of study about the BSF, there is a less information about composition of digestive enzyme of the BSF larva. Experimentally, there is no evidence about characterization of digestive enzyme of the BSF. We investigated biochemical property of digestive enzyme released from the salivary and gut of the BSF. Through digestive enzyme assay, we found that the BSF has amylase, lipase and protease activity in gut extracts, resulting in that the BSF belong to polyphagous insect group. In the BSF gut, trypsin-like protease activity showed one peak at various temperature and pH condition. This result means the BSF has probably a similar form of trypsin-like enzymes. On study of comparison of enzyme activity between the BSF and the housefly using the apiZYM kit, the BSF had more strongly digestive enzyme activity than one of the housefly about leucine arylamidase, alpha-galactosidase, beta-galactosidase, alpha-mannosidase and alpha-fucosidase. This finding supports that the BSF can ingest raw waste far more efficiently than any other known species of fly as reported previously.

Taxonomic resolution of the Nosema/Vairimorpah clade has been augmented with DNA sequences of the small subunit (SSU) and large subunit (LSU) ribosomal RNA (rRNA) and the arrangement of SSU and LSU. Based on the two characteristics, the clade is largely divided into two, i.e. 'true' Nosema sub-group and 'non-true' Nosema sub-group within the clade. Our study shows that a novel Nosema species isolated from Pieris rapae has mixed characteristics of the 'true' and non 'true' Nosema sub-group based on the topology of SSU and LSU sequences, and rRNA of the isolate is normally organized. Additionally, the length of ITS can be a diagnostic tool to distinguish 'true' Nosema from non 'true' Nosema in the Nosema/Vairimorpha clade based on its nucleotide length as reported before. To our knowledge, this is the first report of recombination event in the Nosema/Vairimorpha clade.

The Wolbachia bacterium, one of the most prevalent endosymbiotic bacteria, is known to induce reproductive anomalies such as cytoplasmic incompatibility, feminization, male killing and parthenogenesis in various arthropod species. The bacterium is considered to have had huge impacts on hosts' reproductive biology, immunity, evolution, and molecular machineries. Infection surveys on the bacterium have rather been limited to specific taxa that are mainly of economical importance or conducted with randomly collected organisms. Here we investigated infection frequency of Wolbachia in 206 Coleopteran insects collected from Korea. Among them 28 species (13.59%) across families proved to harbor Wolbachia. The phylogenetic trees based on the partial 16s rRNA gene and the partial Wolbachia surface protein (wsp) gene of Wolbachia show that all the Wolbachia strains belong to either Supergroup A or B and Wolbachia evolved independently from its hosts. In addition, the cophylogenetic analysis of the 16s rRNA gene and wsp gene implies that there have been horizontal DNA transfers and recombination events within and between divergent Wolbachia supergroups.

Microsporidia are obligate fungal intracellular parasites of all animal taxa. Among them the genus Nosema (Nosematidae) is known as the most common entomopathogen. Of these parasites, the ribosomal organization is one of the most pronounced molecular characteristics. One type is the normalarrangement of small subunit (SSU)-internal transcribed spacer (ITS)-large subunit (LSU) in the DNA sequence order. The other is the reverse arrangement of LSU-ITS-SSU. The latter is assigned to be the ‘true’ Nosema in the Nosema/Vairimorpha clade. However, we found that the SSU sequence of a strain of Nosema species having the normal arrangement of its rRNA sequence seemed to be more closely related to the ‘true’ Nosemagroup. Consequently we have further analyzed the complete sequence of rRNA. The results imply that there might be arecombination event in its rRNA evolution and/or the strain may form a novel group near the ‘true’ Nosema group. Interestingly both SSU and LSU of the ‘true’ Nosema and others may be under different selection pressure. We have also found that the size of ITS is distinct between the ‘true’ Nosema and other microsporidian species within the Nosema/Vairimorpha clade. This feature should be a useful diagnostic tool to distinguish the ‘true’ Nosema from others in the clade.

This study investigated the antioxidant effect of Hermetia illucens larvae using different extraction temperatures and solvents. We found significant differences in total phenolic content (TPC), total flavonoid content (TFC), an in three antioxidant indexes 2,2-diphenyl-1-picrylhydrazyl (DPPH), 1,1’-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and ferric-reducing antioxidant power (FRAP) contents, among the samples depending on the extraction temperature and solvent used. The sample extracted with water at 45℃ (HIW-45℃) showed the highest TPC, DPPH, ABTS, and FRAP contents, while the sample extracted with water at 90℃ (HIW-90℃) showed the highest TFC. These differences can be due to the different chemical structures of the extracted components. Based on these results, HIW-45℃ was the optimal extraction method for Hermetia illucens. We intend to further investigate the availability of functional materials for Hermetia illucens using this method.

The present study investigated the feasibility of using the ethanolic extract of Hermetia illucens larvae (HIE) as a whitening improvement material. In cell viability assays using B16F1 melanoma cells, no cytotoxicity was recorded up to 200 μg·mL-1 of HIE. Moreover, while tyrosinase inhibitory activity increased, melanin content decreased in a dose-dependent manner, indicating that HIE likely inhibited tyrosine-induced intracellular melanin biosynthesis in B16F1 melanoma cells. Therefore, HIE is expected to serve as a potent whitening improvement material.