• Korean Journal of Clinical Laboratory Science
• /
• v.54 no.2
• /
• pp.142-148
• /
• 2022

This survey was performed to monitor the spread of specific mosquito-borne pathogens at Jeonbuk. The frequency of occurrence of mosquito borne pathogens including Japanese encephalitis virus, West Nile virus, Zika virus, and yellow fever virus was assessed by collecting mosquitoes twice a month from March to December 2021 from various areas in Jeonbuk. A total of 15,975 mosquitoes from 15 species and 7 genera were collected. The highest number of 9,116 mosquitoes (trap index: TI, 506.4) were collected in the Wanju cattle pen, followed by the habitat for migratory birds and the downtown area in Jeonju. In the Gunsan habitat for migratory birds, 3,217 mosquitoes (TI, 178.7) were collected in the reed fields, 356 (TI, 19.7) in the men's toilets, and 1,948 (TI, 108.2) in the women's toilets. In Jeonju, 677 mosquitoes (TI, 37.6) were collected in the Deokjin park, 358 (TI, 19.8) in the Deokjin-gu office, and 303 (TI, 16.8) at the Jeonbuk National University. The largest population of mosquitoes was collected in the men's toilets in Gunsan and the Deokjin Park in downtown Jeonju. The results of the RT-PCR confirmation to determine the pathogen infection of the collected mosquitoes were all negative. These results provide a basis for tackling integrated mosquito-borne diseases in the Jeonbuk region.

• Proceedings of the IEEK Conference
• /
• 2001.06d
• /
• pp.53-56
• /
• 2001

This paper presents a computationally efficient post-processing algorithm for HDTV. The proposed algorithm can reduce both blocking artifacts and mosquito noise while preserving the sharpness and naturalness of the reconstructed video signal. Performance improvements compared with other techniques are obtained according to simulation results.

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.452-453
• /
• 2005

• 대한예방의학회:학술대회논문집
• /
• 2005.10a
• /
• pp.486-486
• /
• 2005

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2006.04a
• /
• pp.180-181
• /
• 2006

• Proceedings of the Zoological Society Korea Conference
• /
• 2003.08a
• /
• pp.143.1-143
• /
• 2003

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
• /
• 2003.08a
• /
• pp.173.1-173
• /
• 2003

No Abstract, See Full Text

• BMB Reports
• /
• v.40 no.2
• /
• pp.163-171
• /
• 2007

Functional elements of the conserved helix 7 in the poreforming domain of the Bacillus thuringiensis Cry $\delta$- endotoxins have not yet been clearly identified. Here, we initially performed alanine substitutions of four highly conserved aromatic residues, $Trp^{243}$, $Phe^{246}$, $Tyr^{249}$ and $Phe^{264}$, in helix 7 of the Cry4Ba mosquito-larvicidal protein. All mutant toxins were overexpressed in Escherichia coli as 130-kDa protoxins at levels comparable to the wild-type. Bioassays against Stegomyia aegypti mosquito larvae revealed that only W243A, Y249A or F264A mutant toxins displayed a dramatic decrease in toxicity. Further mutagenic analysis showed that replacements with an aromatic residue particularly at $Tyr^{249}$ and $Phe^{264}$ still retained the high-level toxin activity. In addition, a nearly complete loss in larvicidal activity was found for Y249L/F264L or F264A/ Y249A double mutants, confirming the involvement in toxicity of both aromatic residues which face towards the same direction. Furthermore, the Y249L/F264L mutant was found to be structurally stable upon toxin solubilisation and trypsin digestion, albeit a small change in the circular dichroism spectrum. Altogether, the present study provides for the first time an insight into the highly conserved aromaticity of $Tyr^{249}$ and $Phe^{264}$ within helix 7 playing an important role in larvicidal activity of the Cry4Ba toxin.

• BMB Reports
• /
• v.34 no.2
• /
• pp.150-155
• /
• 2001

The mosquito-larvicidal Cry4B protein from Bacillus thuringiensis subsp. israelensds was expressed in Escherichia coli. Upon activation by trypsin, the 130-kDa protoxin was processed into the 65-kDa active toxin containing two polypeptide fragments of ca. 47 and ca. 20 kDa. These two polypeptides are products of internal cleavages on the exposed loop connecting helices 5 and 6 in the seven-helical bundle domain. PCR-based mutagenesis was employed to introduce an additional cleavage site into the loop connecting helices 3 and 4. A series of amino acid changes were introduced into the targeted loop, resulting in seven mutant protoxins. Upon digestion with trypsin, a group of mutants with arginine introduced into the loop (EPRNQ, EPNRNQ, EPRNP, ESRNP and SSRNP) produced polypeptide products similar to those of the wild type (EPNNQ). When the loop, SSRNP, was expanded by an insertion of either asparagine (NSSRNP) or valine (VSSRNP), an additional cleavage was detected with proteolytic products of 47,12 and 6 kDa. This cleavage was confirmed to be at the introduced arginine residue by N-terminal sequencing. The mosquito larvicidal assay against Aedes aegypti demonstrated a relatively unchanged toxicity for the mutants without cleavage and reduced toxicity for those with an additional cleavage.

• BMB Reports
• /
• v.39 no.3
• /
• pp.270-277
• /
• 2006

Helices 4 and 5 of the Bacillus thuringiensis Cry4Ba $\delta$-endotoxin have been shown to be important determinants for mosquito-larvicidal activity, likely being involved in membrane-pore formation. In this study, the Cry4Ba mutant protein containing an additional engineered tryptic cleavage site was used to produce the $\alpha4$-$\alpha5$ hairpin peptide by an efficient alternative strategy. Upon solubilization of toxin inclusions expressed in Escherichia coli and subsequent digestion with trypsin, the 130-kDa mutant protoxin was processed to protease-resistant fragments of ca. 47, 10 and 7 kDa. The 7-kDa fragment was identified as the $\alpha4$-loop-$\alpha5$ hairpin via N-terminal sequencing and mass spectrometry, and was successfully purified by size-exclusion FPLC and reversed-phase HPLC. Using circular dichroism spectroscopy, the 7-kDa peptide was found to exist predominantly as an $\alpha$-helical structure. Membrane perturbation studies by using fluorimetric calcein-release assays revealed that the 7-kDa helical hairpin is highly active against unilamellar liposomes compared with the 65-kDa activated full-length toxin. These results directly support the role of the $\alpha4$-loop-$\alpha5$ hairpin in membrane perturbation and pore formation of the full-length Cry4Ba toxin.