Namjung Kim

Molecular cloning and characterization of a glycosyl hydrolase family 9 cellulase distributed throughout the digestive tract of the cricket Teleogryllus emma.

A novel endogenous beta-1,4-endoglucanase (EG) gene belonging to the glycosyl hydrolase family 9 (GHF 9) that is distributed throughout the digestive tract of the cricket Teleogryllus emma was cloned and characterized. This gene, named TeEG-I, consists of eight exons encoding 453 amino acid residues and exists as a single copy in the T. emma genome. TeEG-I possesses all the features, including signature motifs and catalytic domains, of GHF 9 members, sharing high levels of identity with the termite, Mastotermes darwiniensis (64% protein sequence identity), and the cockroach, Panesthia cribrata (62%), GHF 9 cellulases. Recombinant TeEG-I, which is expressed as a 47-kDa polypeptide in baculovirus-infected insect Sf9 cells, showed an optimal pH and temperature of pH 5.0 and 40 degrees C. The K(m) and V(max) values for digestion of carboxymethyl cellulose were 5.4 mg/ml and 3118.4 U/mg, respectively. Northern and Western blot analyses revealed that TeEG-I is present throughout the digestive tract, which correlated with the TeEG-I distribution and cellulase activity in the digestive tract as assayed by immunofluorescence staining and enzyme activity assay, respectively. These results indicate that TeEG-I is distributed throughout the entire digestive tract of T. emma, suggesting a functional role of endogenous TeEG-I in a sequential cellulose digestion process throughout the T. emma digestion tract.

Recycling Agricultural Wastes as Feed for Mealworm ( Tenebrio molitor )

In order to investigate the impact of recycling agricultural wastes as feed for mealworm (Tenebrio molitor), we evaluated the replacing effect by the different level of tangerine shell, Chinese cabbage, king oyster mushroom (Pleurotus eryngii) and Enoki mushroom (Flammulina velutipes) substrates on wheat bran feed. Larval survival rate, larval weight, developmental period of larva, pupation rate and pupal weight were evaluated. In tangerine shell and Chinese cabbage replacement group, no replacing effects found. In all groups replacing by spent King oyster mushroom (Pleurotus eryngii) substrate, survival rate of larva was similar to that of control group but larvae weighed less than control group significantly. Developmental period of larva increases in the group of King oyster mushroom substrate replacement. Larval and pupal weight in Enoki mushroom (Flammulina velutipes) substrate by the level of 40 and 50%, replacement effect showed best results in successive breeding considering pupation rate. It is concluded that replacing 40 and 50% of Enoki mushroom (Flammulina velutipes) substrate is appropriate to substituted diet of Tenebrio molitor larvae.

Website monitoring on the behavior of consumers for educational pet insects.

As the market of educational pet insects is expanding, understanding the consumer needs became more crucial. To achieve the ideal analysis on the market, this research monitored the behavior of consumers. The posting on the blogs of consumers, who have visited insect museums and farms, or have bought insects were collected as data. Moreover, the informational contents, photographs and texts, were analyzed. The results showed that the family-unit visitors with elementary school lower graders were the main type of visitors for their children`s education. The visiting areas were concentrated in Seoul and the Metropolitans of Gyeonggi province, and the visits were mostly occurred during their children`s vacation period. The analysis of posted photographs showed the visitors` high interest in the hands-on program. According to the texts on visitors` blogs, especially, the largest number of visitors satisfied with the variety of program. It implies the necessity of development in diverse and differentiated hands-on program. Otherwise, the programs available to connect insects to other animals and plants should be introduced to reduce aversion against insects, which was reported as the strongest dissatisfaction. In conclusion, diversification on insect species and development in systematized hands-on program seem to be required for the continuous growth of educational pet insects market.

Microarray expression profiling of Spodoptera litura in response to oxidative stress

To examine the expression profile of oxidative stress responsive genes in Spodoptera litura, we constructed a cDNA library from S. litura injected with hydrogen peroxide (H(2)O(2)). Using a microarray chip composed of 2,964 cDNAs, we screened gene expression at 1, 3, 5, 7, and 9 h post H(2)O(2) injection. Data were clustered into 15 groups of genes that behave similarly across each time course. Seventy-three genes were identified as being at least twofold up- or downregulated after treatment with H(2)O(2) in S. litura. We constructed expressed sequence tags (ESTs) for genes that changed at least twofold after treatment with H(2)O(2) . The functional classification of these ESTs based on Gene Ontology showed that the ESTs are rich in genes involved in oxidoreductase activity (5.7%), defense (14.3%), cellular process (22.9%), and development (17.1%).

A ecological survey of Taraka hamada (Druce) (Lepidoptera, Lycaenidae) in Korea

Taraka hamada is known as the sole aphidophagous lycaenid butterfly in Korea. The species specifically preys upon Ceratovacuna japonica which lives in bamboo forests. During several years, the species has been received attention from the field of industrial insects in order to commercialize as a pet. However, an ecological character of the species have been unclear in Korea. We carried out a survey for basic ecology and distribution of the two species for 2010 to 2012. As the results, both species only cohabit at Pseudosasa japonica in our investigation. C. japonica is widely distributed from the host plant. Population density of T. hamada is synchronized with the density changes of C. japonica. Their densities are gradually decreased from the point to the investigation and significantly declined in mid-june. The maximum population density of both species shows at the basal part of a leaf. The last-larval instar of T. hamada may seem to be reaching at stage. The adults of T. hamada are killed within two minutes when they were exposed to the sun.