• Journal of the Korean Institute of Navigation
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• v.17 no.3
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• pp.85-92
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• 1993

In connection to the design of high speed vessels, the numerical simulation is carried out to make clear the property of flows and breaking phenomena around the catamaran. It is because the bradking phenome-non is closely related to the free-surface turbulent flow. The free-surface wave and transverse velocity vectors are calculated around the twin and demi hull of the catamaran. Computed results are applied to detect the appearance of sub-breaking waves around the hull. The critical condition for their appearance is studied at two Froude numbers of 0.45 and 0.95. The nu-merical analysis shows that the breaking is more serious near the twin hull rather the demi hull. To simu-late the flows, the Navier-Stokes solver is invoked with a free-surface. The computation is made only in half a domain because it is symmetric in the shape.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.59-59
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• 2015

Cryptococcus neoformans causes life-threatening meningoencephalitis in humans, but the treatment of cryptococcosis remains challenging. To develop novel therapeutic targets and approaches, signaling cascades controlling pathogenicity of C. neoformans have been extensively studied but the underlying biological regulatory circuits remain elusive, particularly due to the presence of an evolutionarily divergent set of transcription factors (TFs) in this basidiomycetous fungus. In this study, we constructed a high-quality of 322 signature-tagged gene deletion strains for 155 putative TF genes, which were previously predicted using the DNA-binding domain TF database (http://www.transcriptionfactor.org/). We tested in vivo and in vitro phenotypic traits under 32 distinct growth conditions using 322 TF gene deletion strains. At least one phenotypic trait was exhibited by 145 out of 155 TF mutants (93%) and approximately 85% of the TFs (132/155) have been functionally characterized for the first time in this study. Through high-coverage phenome analysis, we discovered myriad novel TFs that play critical roles in growth, differentiation, virulence-factor (melanin, capsule, and urease) formation, stress responses, antifungal drug resistance, and virulence. Large-scale virulence and infectivity assays in insect (Galleria mellonella) and mouse host models identified 34 novel TFs that are critical for pathogenicity. The genotypic and phenotypic data for each TF are available in the C. neoformans TF phenome database (http://tf.cryptococcus.org). In conclusion, our phenome-based functional analysis of the C. neoformans TF mutant library provides key insights into transcriptional networks of basidiomycetous fungi and ubiquitous human fungal pathogens.

• Journal of Microbiology and Biotechnology
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• v.27 no.6
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• pp.1171-1179
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• 2017

Butanol is a promising alternative to ethanol and is desirable for use in transportation fuels and additives to gasoline and diesel fuels. Microbial production of butanol is challenging primarily because of its toxicity and low titer of production. Herein, we compared the transcriptome and phenome of wild-type Escherichia coli and its butanol-tolerant evolved strain to understand the global cellular physiology and metabolism responsible for butanol tolerance. When the ancestral butanol-sensitive E. coli was exposed to butanol, gene activities involved in respiratory mechanisms and oxidative stress were highly perturbed. Intriguingly, the evolved butanol-tolerant strain behaved similarly in both the absence and presence of butanol. Among the mutations occurring in the evolved strain, cis-regulatory mutations may be the cause of butanol tolerance. This study provides a foundation for the rational design of the metabolic and regulatory pathways for enhanced biofuel production.

• The Plant Pathology Journal
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• v.32 no.4
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• pp.300-310
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• 2016

Pathogen infection in plants induces complex responses ranging from gene expression to metabolic processes in infected plants. In spite of many studies on biotic stress-related changes in host plants, little is known about the metabolic and phenotypic responses of the host plants to Pseudomonas cichorii infection based on image-based analysis. To investigate alterations in tomato plants according to disease severity, we inoculated plants with different cell densities of P. cichorii using dipping and syringe infiltration methods. High-dose inocula (${\geq}10^6cfu/ml$) induced evident necrotic lesions within one day that corresponded to bacterial growth in the infected tissues. Among the chlorophyll fluorescence parameters analyzed, changes in quantum yield of PSII (${\Phi}PSII$) and non-photochemical quenching (NPQ) preceded the appearance of visible symptoms, but maximum quantum efficiency of PSII ($F_v/F_m$) was altered well after symptom development. Visible/near infrared and chlorophyll fluorescence hyperspectral images detected changes before symptom appearance at low-density inoculation. The results of this study indicate that the P. cichorii infection severity can be detected by chlorophyll fluorescence assay and hyperspectral images prior to the onset of visible symptoms, indicating the feasibility of early detection of diseases. However, to detect disease development by hyperspectral imaging, more detailed protocols and analyses are necessary. Taken together, change in chlorophyll fluorescence is a good parameter for early detection of P. cichorii infection in tomato plants. In addition, image-based visualization of infection severity before visual damage appearance will contribute to effective management of plant diseases.