Hyeyoung Koo

Ectopic Expression of a Cecropin Transgene in the Human Malaria Vector Mosquito Anopheles gambiae (Diptera: Culicidae): Effects on Susceptibility to Plasmodium

Abstract Genetically altering the disease vector status of insects using recombinant DNA technologies is being considered as an alternative to eradication efforts. Manipulating the endogenous immune response of mosquitoes such as the temporal and special expression of antimicrobial peptides like cecropin may result in a refractory phenotype. Using transgenic technology a unique pattern of expression of cecropin A (cecA) in Anopheles gambiae was created such that cecA was expressed beginning 24 h after a blood meal in the posterior midgut. Two independent lines of transgenic An. gambiae were created using a piggyBac gene vector containing the An. gambiae cecA cDNA under the regulatory control of the Aedes aegypti carboxypeptidase promoter. Infection with Plasmodium berghei resulted in a 60% reduction in the number of oocysts in transgenic mosquitoes compared with nontransgenic mosquitoes. Manipulating the innate immune system of mosquitoes can negatively affect their capacity to serve as hosts for the development of disease-causing microbes.

DNA barcode-based molecular identification system for fish species

In this study, we applied DNA barcoding to identify species using short DNA sequence analysis. We examined the utility of DNA barcoding by identifying 53 Korean freshwater fish species, 233 other freshwater fish species, and 1339 saltwater fish species. We successfully developed a web-based molecular identification system for fish (MISF) using a profile hidden Markov model. MISF facilitates efficient and reliable species identification, overcoming the limitations of conventional taxonomic approaches. MISF is freely accessible at http://bioinfosys.snu.ac.kr:8080/MISF/misf.jsp.

A machine learning based method for the prediction of G protein-coupled receptor-binding PDZ domain proteins

G protein-coupled receptors (GPCRs) are part of multi-protein networks called ‘receptosomes’. These GPCR interacting proteins (GIPs) in the receptosomes control the targeting, trafficking and signaling of GPCRs. PDZ domain proteins constitute the largest protein family among the GIPs, and the predominant function of the PDZ domain proteins is to assemble signaling pathway components into close proximity by recognition of the last four C-terminal amino acids of GPCRs. We present here a machine learning based approach for the identification of GPCR-binding PDZ domain proteins. In order to characterize the network of interactions between amino acid residues that contribute to the stability of the PDZ domain-ligand complex and to encode the complex into a feature vector, amino acid contact matrices and physicochemical distance matrix were constructed and adopted. This novel machine learning based method displayed high performance for the identification of PDZ domain-ligand interactions and allowed the identification of novel GPCR-PDZ domain protein interactions.

Korea Barcode of Life Database System (KBOL)

A major concern regarding the collection and storage of biodiversity information is the inefficiency of conventional taxonomic approaches in dealing with a large number of species. This inefficiency has increased the demand for automated, rapid, and reliable molecular identification systems and large-scale biological databases. DNA-based taxonomic approaches are now arguably a necessity in biodiversity studies. In particular, DNA barcoding using short DNA sequences provides an effective molecular tool for species identification. We constructed a large-scale database system that holds a collection of 5531 barcode sequences from 2429 Korean species. The Korea Barcode of Life database (KBOL, http://koreabarcode.org) is a web-based database system that is used for compiling a high volume of DNA barcode data and identifying unknown biological specimens. With the KBOL system, users can not only link DNA barcodes and biological information but can also undertake conservation activities, including environmental management, monitoring, and detecting significant organisms.

A New Record of Betaeus gelasinifer Nomura and Komai (Decapoda: Caridea: Alpheidae) from Korea

An alpheid shrimp Betaeus gelasinifer Nomura and Komai, 2000 new to Korean waters is described and illustrated based on two specimens collected from Changseun and Ulleungdo Island, Korea. This is the first record of B. gelasinifer outside Japanese waters. B. gelasinifer is readily separated from B. granulimanus Yokoya, 1927, the only member of Betaeus from Korea by the morphological differences in the first pereopods and the diaeresis of uropod. Brief note on the armature of cutting edge of the chela of the left first pereopod in Korean female specimen of B. gelasinifer is provided.

Synalpheus jejuensis n. sp. (Crustacea: Decapoda: Alpheidae) from Korea based on morphological and molecular study

We describe Synalpheus jejuensis n. sp. on the basis of 17 specimens collected around Jejudo Island, Korea. The new species is most similar to S. tumidomanus but can be distinguished from that species by shorter scaphocerite, upturned blunt tubercle rather than an acute spine on the superior margin of major chela, and teeth on the ventral margin of the pleura. The DNA barcoding using the mitochondrial cytochrome c oxidase subunit I (COI) gene fragment was employed in these two species. The intraspecific sequence divergence of the COI gene of S. jejuensis n. sp. ranges between 0% and 2.1%, while that of S. tumidomanus ranges between 0.2% and 0.4%. The sequence divergence between two species is 20.1%. DNA barcoding results provide further evidence that these two species are distinct. The discovery of S. jejuensis n. sp. is biogeographically important because the species diversity of Synalpheus is low in temperate region.

First Record of Snapping Shrimp, Prionalpheus sulu (Decapoda: Caridea: Alpheidae) in Korea

The alpheid shrimps collected from Jejudo Island turned out to be a species belonging to the genus Prionalpheus which is an unreported genus from Korean waters. In this paper, Prionalpheus sulu is reported for the first time from Korean waters with description and illustration.

Differential Expression of NCAM-180 in the Olfactory System and Retina of the Rat

The expression of the neural cell adhesion molecule-180 (NCAM-180), which accumulates at contact sites between cells and may be responsible for the stabilization of cell contacts, was studied in the olfactory system and retina of developing and adult rats. From embryonic day 12 onwards, which was the earliest stage examined, the NCAM-180 pathway directing to the presumptive olfactory bulb was observed. In later stages, olfactory neurons and fasciculating axons in the olfactory epithelium and nerve fiber layer and glomeruli of the olfactory bulb expressed NCAM-180. From postnatal day 0, immunolabelling pattern of the olfactory epithelium and olfactory bulb were the same as that during later stages. NCAM-180 immunoreactivity was present on differentiating retinal cells and persisted on those cells throughout adulthood. However, contrary to the olfactory nerve which remained detectable in the adult, the optic nerve was only transiently expressed with NCAM-180 and was no longer detectable in the adult. The presence of NCAM-180 in olfactory tissues suggests their possible role in pathfinding, differentiation, fasciculation and synaptic plasticity. The continued presence of NCAM-180 in the olfactory system examined may underlie its continuous cell turnover and regenerative capacity. The continuous expression of NCAM-180 in ganglion cells, bipolar cells and photoreceptor cells, also suggests potential regenerating capability and some plastic functions for these cells in the adult. Since the expression of NCAM-180 by the optic nerve was restricted to the period of special histogenetic events, for example, during axonal growth and synaptogenesis, it is possible that the lack of NCAM-180 in the adult optic nerve might cause a nonpermissive environment for the regeneration and result in regenerative failure of this system.