• The Transactions of the Korea Information Processing Society
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• v.13 no.4
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• pp.189-198
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• 2024

Lipreading is one of the important parts of speech recognition, and several studies have been conducted to improve the performance of lipreading in lipreading systems for speech recognition. Recent studies have used method to modify the model architecture of lipreading system to improve recognition performance. Unlike previous research that improve recognition performance by modifying model architecture, we aim to improve recognition performance without any change in model architecture. In order to improve the recognition performance without modifying the model architecture, we refer to the cues used in human lipreading and set other regions such as chin and cheeks as regions of interest along with the lip region, which is the existing region of interest of lipreading systems, and compare the recognition rate of each region of interest to propose the highest performing region of interest In addition, assuming that the difference in normalization results caused by the difference in interpolation method during the process of normalizing the size of the region of interest affects the recognition performance, we interpolate the same region of interest using nearest neighbor interpolation, bilinear interpolation, and bicubic interpolation, and compare the recognition rate of each interpolation method to propose the best performing interpolation method. Each region of interest was detected by training an object detection neural network, and dynamic time warping templates were generated by normalizing each region of interest, extracting and combining features, and mapping the dimensionality reduction of the combined features into a low-dimensional space. The recognition rate was evaluated by comparing the distance between the generated dynamic time warping templates and the data mapped to the low-dimensional space. In the comparison of regions of interest, the result of the region of interest containing only the lip region showed an average recognition rate of 97.36%, which is 3.44% higher than the average recognition rate of 93.92% in the previous study, and in the comparison of interpolation methods, the bilinear interpolation method performed 97.36%, which is 14.65% higher than the nearest neighbor interpolation method and 5.55% higher than the bicubic interpolation method. The code used in this study can be found a https://github.com/haraisi2/Lipreading-Systems.

• Microbiology and Biotechnology Letters
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• v.39 no.1
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• pp.77-85
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• 2011

The antibacterial activities of silver nanoparticles (Ag-NPs) were studied with respect to Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli by observing the bacterial cells treated or not with Ag-NPs by FE-SEM as well as measuring the growth curves, formation of bactericidal ROS, protein leakage, and lactate dehydrogenase activity involved in the respiratory chain. Bacterial cells were treated with Ag-NPs powder, and the growth rates were investigated under varying concentrations of Ag-NPs, incubation times, incubation temperatures, and pHs. As a result, S. aureus and E. coli were shown to be substantially inhibited by Ag-NPs, and the antibacterial activity of Ag-NPs did not fluctuate with temperature or pH. These results suggest that Ag-NPs could be used as an effective antibacterial material.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.523-528
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• 1998

We isolated microorganism secreting antimicrobial substance from tomato and identified as Enterococcus faecium. This substance was completely inactivated by pretense treatment and retained activity after catalase treatment. This result indicated that the antimicrobial activity of this substance was due to proteinaceous substance known as bacteriocin. The bacteriocin inhibited growth of Gram positive bacteria, such as Listeria monocytogenes, Leuconostoc mesenteroides, Lactobacillus plantarum, Streptococcus agalactiae, Streptococcus pyrogenes, and Gram negative bacteria, such as Pseudomonas aeruginosa. Purification of the bacteriocin was achieved by ethanol precipitation, ion exchange chromatography on CM Sepharose CL-6B, and gel filtration on Sephacryl S-100 HR. After these purification steps, the specific activity of the bacteriocin was increased 35.8 fold compared with culture broth. Purified bacteriocin was shown single band on SDS-PAGE and molecular weight was estimated 51 kDa. The residual activity of this bacteriocin was 3.3% at 10$0^{\circ}C$ for 60 min, and this bacteriocin was stable at pH 2~7.

• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.137-142
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• 1998

Helicobacter pylori is a Gram-negative bacterium which causes chronic gastritis and is associated with gastric ulcer, duodenal ulcer and gastric carcinoma. In the process of screening of antibacterial activities against H. pylori from soil microorganisms, fungus No. 60686 was isolated. After fermentation of No.60686, the antibacterial compound was isolated, purified and followed by extraction of mycelium with organic solvents, acetone and ethyl acetate, through silica gel chromatography, LH-20 gel chromatography and HPLC. As a result of the structural analyses of the compound by IR, $^1$H- and $^{13}$C-NMR, FAB/Mass spectrophotometer, the compound having the antimicrobial activity was identified as chaetoglobosin A ($C_{32}H_{36}N_2O_5$), a cytochalasan derivative. The antimicrobial activity of chaetoglobosin A was tested against Gram-positive and negative bacteria by paper disk method. Among the test strains of 9 Gram-positive bacteria and 18 Gram-negative bacteria containing 4 H. pylori strains, the growth of 4 H. pylori strains and 3 S. aureus strains (SG 511, 285 and 503) was only inhibited by chaetoglobosin A. Also it was shown that its growth inhibition against H. pylori strains was stronger than that against S. aureus strains at the treatment of the same concentration. Therefore it was concluded that chaetoglobosin A has a specific growth inhibition against H. pylori of the tested bacteria.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.274-280
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• 2005

Pasteurella multocida is known to cause widespread infections in husbandry. To induce homologous and heterologous immunity against the infections, outer membrane proteins (OMPs) in the envelope of P. multocida are thought to be attractive vaccine candidates. Outer membrane protein H is considered as the major component of OMPs. In this study, a gene for OmpH was isolated from pathogenic P. multocida serogroup A. The gene was composed of 1,047 nucleotides coding 348 amino acids with signal peptide of 20 amino acids. The amino acid composition showed about 80 to 98 per cent sequence homologies among other 10 strains of P. multocida serogroup A, reported so far. A recombinant ompH, from which signal peptide was truncated, was generated using pRSET A to name 'pRSET A/OmpH-F2'. The pRSET A/OmpH-F2 was well expressed in E. coli BL21(DE3). The truncated OmpH was purified using nickel-nitrilotriacetic acid (Ni-NTA) affinity column chromatography. Its molecular weight was registered to be 40 kDa on SDS-PAGE gel. In order to generate immunesera against the OmpH, 50 ug of the protein was intraperitoneally injected into mice three times. The anti-OmpH immuneserum recognized about $5{\times}10^{-2}$ng quantity of the purified OmpH. It can be used for an effective vaccine production to prevent fowl cholera caused by pathogenic P. multocida (Serogroup A).

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.447-453
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• 1989

In order to study the transfer of antibiotics resistance genes of the genetically cloned bacteria in water environments, DK1 strain, which is resistant to kanamycin (Km), chloramphenicol (Cm), streptomycin (Sm), and sulfadiazine (Su), was selected from the Gram-negative bacterial isolates from wastewater. One of 4 plasmids harboured in the DK1 strain was found to possess Km$^{${\gamma}$}$Cm$^{${\gamma}$}$ gene and be about 68 kb in size, and it was designated as pDK101. The plasmid of pDK101 was also found to have 16, 32, and 6 restriction sites for EcoRI. .PstI, and SalI, respectively. From the digestion fragments of pDK101 plasmid and pKT230 used as a vector by EcoRI restriction endonuclease, pDT309 and pDT529 were constructed as chimeric plasmids which possess Km$^{${\gamma}$}$Cm$^{${\gamma}$}$ gene and are 30.9 and 52.9 kb in size, respectively. When the chimeric plasmids were trasformed into E. coli C600 or E. coli HB101, transformants of DKC601, DKC602, DKH102, and DKH103 were obtained as cloned bacterial cells. The Km$^{${\gamma}$}$Cm$^{${\gamma}$}$ genes were well expressed in those cloned cells and the chimeric plasmids were clearly detected in the cloned cells of DKC601 and DKH103.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.454-460
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• 1989

Antibiotics resistance genes both in natural bacterial isolates and the genetically cloned bacteria were comparatively studied for their transfer frequencies by the method of conjugation in several different water environments. The Kmr genes in both kinds of bacteria were transferred more frequently in autoclaved wastewater of laboratory environment than in natural river water, but in Luria Bertani (LB) broth medium under the laboratory conditions the transfer frequences of the genes were much higher than in the autoclaved wastewater. The transfer frequencies at 2$0^{\circ}C$ and 3$0^{\circ}C$ were not much different in any water environments. The Km$^{${\gamma}$}$ genes of the genetically cloned bacteria and the natural isolates were transferred at the same frequency both in natural river water and in the autoclaved wastewater of laboratory environment, but in LB broth under laboratory conditions the transfer frequencies were lowered by 10$^{-3}$ to 10$^{-4}$ in the genetically cloned cells than the natural isolates. When donors of different cloned cells were conjugated with recipient of a natural isolates, the Km$^{${\gamma}$}$ genes of different donor cells were transferred at the about same frequency, but the same donor of the cloned cell were conjugated with recipients of different natural isolates, the transfer of Km$^{${\gamma}$}$ gene of the cloned cell showed some differences of 101 to 102 in frequency.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.126-133
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• 2015

Ten types of farm-made brewing vinegars were collected and four high acetic acid-producing strains (CV1, CV3, CV5, and CV6) were isolated. Among them strain CV1, exhibiting highly alcohol-resistant and acetic acid-producing properties, was selected and its taxonomic properties were investigated by phenotypic (particularly chemotaxonomic) characterization and phylogenetic inference based on 16S rRNA gene sequence analysis. On SM broth agar, cells of strain CV1 were gram-stainingnegative and formed pale white colonies with smooth to rough surfaces. Strain CV1 produced acetate from ethanol and was resistant to up to 8% (v/v) ethanol in LM broth. Strain CV1 had a G+C content of 61.0 mol%, contained meso-DAP as the cell wall amino acid, and possessed Q-10 as the major ubiquinone. A comparison of 16S rRNA gene sequences showed that strain CV1 was most closely related to Gluconacetobacter saccharivorans (≥99.0% identity). In liquid media, the optimum growth conditions for acetic acid production were 30℃ and pH >3.0 and strain CV1 produced 9.3% and 8.4% acetic acids from 10% and 9% alcohol concentrations, respectively.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.276-284
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• 2008

A lactic acid bacterium having antifungal activity was isolated from kimchi. It was identified as Lactobacillus plantarum based on its morphological and biochemical properties, and 16S rRNA sequence, and designated as Lb. plantarum AF1. This isolate inhibited the growth of Aspergillus flavus ATCC 22546, A. fumigatus ATCC 96918, A. petrakii PF-1, A. ochraceus PF-2, A. nidulans PF-3, Epicoccum nigrum KF-1, and Cladosporium gossypiicola KF-2 under a dual culture overlay assay. Also, the antimicrobial activity was found to be active against various species of Gram-positive and Gram-negative bacteria. The antifungal activity was found to be stable after heat ($121^{\circ}C$, 15 min) and proteolytic enzyme treatment, but it was unstable over pH 5.0. The antifungal compound(s) was estimated to have a low molecular mass (below 3,000 Da).

• Microbiology and Biotechnology Letters
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• v.29 no.2
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• pp.84-89
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• 2001

Isolation and Characterization of Cathepsin B inhibitor Produced by Streptomyces luteogriseus KT-IO. Han, Kil~Hwan and Sang~Dal Kim*. Department of Applied Microbiology, Yeungnam Universit}/t Kyongsan 712749, Korea - The cathepsin B inhibitor produced by Streptomyces luteogriseus KT-IO was very stable in heat, acidic and alkaline conditions. The cathepsin B inhibitor was isolated from the extracted fraction of culture broth with butanol, methanol and chloroform subsequently, the inhibitor was purified with following several column chromatography sLlch as DEAE-Sephadex A-25, Sephadex G-15, silica gel 60, Sephadex LH-20, and preparative HPLC. The cathepsin B inhibitor showed positively to detective reaction of ninhydrine, 5% H2S04, iodine, but negatively to the reaction of Ehrlich's reagent, DNS, aniline. The molecular formular of cathepsin B inhibitor was elucidated by JR, lH and 13C-NMR, FAB mass and elemental analyzer. Consequently, it was identified as C4HlI04N6. The cathepsin B inhibitor had the mode of competitive inhibition with the reaction of cathepsin B.