• The Plant Pathology Journal
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• v.39 no.2
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• pp.207-219
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• 2023

Soft rot is a widespread, catastrophic disease caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) that severely damages the production of Amorphophallus spp. This study evaluated the rhizosphere bacterial and fungal communities in Pcc-infected and uninfected plants of two species of Amorphophallus, A. muelleri and A. konjac. Principal component analysis showed that the samples formed different clusters according to the Pcc infection status, indicating that Pcc infection can cause a large number of changes in the bacterial and fungal communities in the Amorphophallus spp. rhizosphere soil. However, the response mechanisms of A. muelleri and A. konjac are different. There was little difference in the overall microbial species composition among the four treatments, but the relative abundances of core microbiome members were significantly different. The relative abundances of Actinobacteria, Chloroflexi, Acidobacteria, Firmicutes, Bacillus, and Lysobacter were lower in infected A. konjac plants than in healthy plants; in contrast, those of infected A. muelleri plants were higher than those in healthy plants. For fungi, the relative abundances of Ascomycota and Fusarium in the rhizosphere of infected A. konjac plants were significantly higher than those of healthy plants, but those of infected A. muelleri plants were lower than those of healthy plants. The relative abundance of beneficial Penicillium fungi was lower in infected A. konjac plants than in healthy plants, and that of infected A. muelleri plants was higher than that of healthy plants. These findings can provide theoretical references for further functional research and utilization of Amorphophallus spp. rhizosphere microbial communities in the future.

• Microbiology and Biotechnology Letters
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• v.51 no.3
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• pp.257-267
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• 2023

The potential polyhydroxyalkanoates (PHA)-producing bacteria, Bacillus megaterium PP-10, was successfully isolated and studied its feasibility for utilization of pineapple peel waste (PPW) as a cheap carbon substrate. The PPW was pretreated with 1% (v/v) H₂SO₄ under steam sterilization and about 26.4 g/l of total reducing sugar (TRS) in pineapple peel hydrolysate (PPH) was generated and main fermentable sugars were glucose and fructose. A maximum cell growth and PHA concentration of 3.63 ± 0.07 g/l and 1.98 ± 0.09 g/l (about 54.58 ± 2.39%DCW) were received in only 12 h when grown in PPH. Interestingly, PHA productivity and biomass yield (Y_x/s) in PPH was about 4 times and 1.5 times higher than in glucose. To achieve the highest DCW and PHA production, the optimal culture conditions e.g. carbon to nitrogen ratios of 40 mole/mole, incubation temperature at 35℃ and shaking speed of 200 rpm were performed and a maximum DCW up to 4.24 ± 0.04 g/l and PHA concentration of 2.68 ± 0.02 g/l (61% DCW) were obtained. The produced PHA was further examined its monomer composition and found to contain only 3-hydroxybutyrate (3HB). This finding corresponded with the presence of class IV PHA synthase gene. Finally, certain thermal properties of the produced PHA i.e. the melting temperature (T_m) and the glass transition temperature (T_g) were about 176℃ and -4℃, respectively whereas the M_w was about 1.07 KDa ; therefore, the newly isolated B. megaterium PP-10 is a promising bacterial candidate for the efficient conversion of low-cost PPH to PHA.

• Journal of Applied Biological Chemistry
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• v.52 no.3
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• pp.121-125
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• 2009

We measured the influence of antifungal antagonists Bacillus subtilis AH18 and Bacillus licheniformis K11 on soil microbial community in microcosms. Both antifungal antagonists were confirmed to suppress hot pepper phytophthora blight. Phospholipid fatty acids (PLFA) were analyzed to investigate the soil microbial community. B. subtilis AH18 changed the total PLFA composition and bio-indicators of PLFA, compared with other treatments. B. subtilis AH18 decreased the proportion of bacteria and gram negative/gram positive bacteria, and increased the fungi/bacteria and anaerobic/aerobic microorganisms. In addition cy19:0/18:$1{\omega}7c$, which means adaptation to unfavorable environmental conditions, was increased by the application of B. subtilis AH18. On the other hand the inoculation of B. licheniformis K11 or combined inoculation of both antifungal strains did not affect soil microbial community. The suppression of phytophthora blight and preservation of indigenous soil microbial community may be achieved by the combined application of B. subtilis AH18 and B. licheniformis K11.

• Journal of Periodontal and Implant Science
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• v.20 no.2
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• pp.161.2-161.2
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• 1990

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.16 no.1
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• pp.17-21
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• 2013

The gut mucosal barrier plays an important role in maintaining a delicate immune homeostasis. The pathogenesis of inflammatory bowel disease (IBD) is considered to involve a defective mucosal immunity along with a genetic predisposition. Recent views have suggested an excessive response to components of the gut microbiota in IBD. A condition of "dysbiosis", with alterations of the gut microbial composition, has been observed in patients with IBD. In this article, the author review recent studies of gut microbiota in IBD, particularly the importance of the gut microbiota in the pathogenesis of pediatric IBD.

• Journal of Ginseng Research
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• v.14 no.1
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• pp.21-26
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• 1990

The chemical composition and stabilities of the purified ginseng invertase were investigated. The purified enzyme was found to be a glycoprotein composed of 80.2% protein and 19.7% total sugar. The protein component of the enzyme was composed of acidic amino acid (9.3%), basic amino acid (48.9%), nonpolar amino acid (21.4%), polar amino acid (20.4%) and 6.1% S-containing amino acid. It showed especially high contents of histidine and serine. The enzyme was inactivated almost completely by the treatment with some proteases (papain, pepsin. trypsin, pancreatin and microbial alkaline pretense) and protein denatllrants (8M urea and 6M guanidine-HC1), bolt not with glyrosidase (${\alpha}$-amylase, ${\beta}$-amylase. glcoamylese and cellullase). btonosaccharides sllch as glilrose, fructose, galactose and mannose did not exert any influence on the enzyme activity. The activity of the enzyme was inhibited by Ag+, Mn2+, Hg2+, Zn2+ and Al3+, whereas Ca2+, Mg2+, Ba2+ and Fe3+ gave rather activating effects on the enzyme activity. The enzyme was relatively stable in the VH range of VH 6 and 8, and at the temperatures below 35$^{\circ}C$.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2004.11a
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• pp.138-149
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• 2004

In this study, we analyzed the gene expression data of Saccharomyces cerevisiae obtained from Holstege et al. 1998 to understand the relationship between expression level and nucleotide sequence of a gene. First, the correlation between gene expression and percent composition of each type of nucleotide was computed. It was observed that nucleotide 'G' and 'C' show positive correlation (r ${\geq}$ 0.15), 'A' shows negative correlation (r ${\approx}$ -0.21) and 'T' shows no correlation (r ${\approx}$ 0.00) with gene expression. It was also found that 'G+C' rich genes express more in comparison to 'A+T' rich genes. We observed the inverse correlation between composition of a nucleotide at genome level and level of gene expression. Then we computed the correlation between dinucleotides (e.g. AA, AT, GC) composition and gene expression and observed a wide variation in correlation (from r = -0.45 for AT to r = 0.35 for GT). The dinucleotides which contain 'T' have wide range of correlation with gene expression. For example, GT and CT have high positive correlation and AT have high negative correlation. We also computed the correlation between trinucleotides (or codon) composition and gene expression and again observed wide range of correlation (from r = -0.45 for ATA r = 0.45 for GGT). However, the major codons of a large number of amino acids show positive correlation with expression level, but there are a few amino acids whose major codons show negative correlation with expression level. These observations clearly indic ate the relationship between nucleotides composition and expression level. We also demonstrate that codon composition can be used to predict the expression of gene in a given condition. Software has been developed for calculating correlation between expression of gene and codon usage.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.713-717
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• 1994

Effects of packing materials on the gas compositions in package of fresh peeled garlic (Allium sativum L.) were investigated. The fresh peeled garlics packed in $20,\;40,\;60\;{\mu}m$ LDPE and $30\;{\mu}m$ HDPE pouches were stored at $20^{\circ}C$, 76% RH. The variables including respiration characteristics, gas compositions, general appearance, and film permeabilities to $O_2$, $CO_2$ and $H_2O$ vapor were measured. A model was evaluated for the prediction of $O_2$ and $CO_2$ equilibrium concentrations inside packages and for the optimization of packaging parameters. Experimental and simulated gas composition results were found to be in good agreement. The $30\;{\mu}m$ HDPE pouch with 4% $O_2$ and 7.5%$CO_2$ equilibrium concentrations conferred the best appearance of peeled garlic, giving 6 days of storage life. As a result, MA seemed to have a beneficial effect on appearance of fresh peeled garlic, possibly due to reduced microbial activity.

• Mass Spectrometry Letters
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• v.9 no.3
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• pp.81-85
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• 2018

In this study, the chemical composition of bacterial melanin isolated from the Streptomyces glaucescens strain was elucidated by ultra-high-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Ultra-high-resolution mass profiles of the microbial melanin product were acquired using a 15 Tesla FT-ICR mass spectrometer in positive and negative ion modes via electrospray ionization to obtain more complete descriptions of the molecular compositions of melanin-derived organic constituents. A mass resolving power of 500,000 (at m/z 400) was achieved for all spectra while collecting 400 scans per sample with a 4 M transient. The results of this analysis revealed that the melanin pigment isolated from S. glaucescens predominantly exhibits CHON and CHO species, which belong to the proteins class of compounds, with the mean C/O and C/N ratios of 4.3 and 13.1, thus suggesting that the melanin could be eumelanin. This analytical approach could be utilized to investigate the molecular compositions of a variety of natural or synthetic melanins. The compositional features of melanins are important for understanding their formation mechanisms and physico-chemical properties.

• Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.132-137
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• 2005

Olive flounder (Paralichthys olivaceus) is one of the most commercially important species of farmed marine fish in Korea. Although techniques for rearing the larva of this species are improving, production costs are also increasing due to microbial influences and genetic degradation caused by successive culturing. Since the demand for healthy seed, which requires eggs of good quality of, is high, we examined the effects of nutrient composition on the size of P. olivaceus eggs. We analyzed floating (live) and sunken (dead) eggs of P. olivaceus from five different hatcheries for their size and amino and fatty acid composition. The sizes of eggs and oil globules from floating vs. sunken eggs were significantly different at p<0.05. No significant relationships were observed, however, among larval length, hatching percentage, and egg and oil globule size. The dry weight and amino acid levels of floating eggs were greater than those of sunken eggs (p<0.05), but no difference in fatty acid content was observed.