• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.709-717
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• 2015

Airborne bacteria from hog farms may have detrimental impacts on human health, particularly in terms of antibiotic resistance and pathogen zoonosis. Despite human health risks, very little is known about the composition and diversity of airborne bacteria from hog farms and hog-related spray fields. We used pyrosequencing analysis of 16S rRNA genes to compare airborne bacterial communities in a North Carolina hog farm and lagoon spray field. In addition, we isolated and identified antibiotic-resistant bacteria from both air samples. Based on 16S rRNA gene pyrosequence analysis, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria were the dominant phyla in airborne bacterial communities from both hog farm and spray field sites. Within the Firmicutes genera, Clostridium spp. were more abundant in the hog farm, whereas Staphylococcus spp. were higher in the spray field. The presence of opportunitic pathogens, including several Staphylococcus species and Propionibacterium acnes, was detected in both bioaerosol communities based on phylogenetic analysis. The isolation and identification of antibiotic-resistant bacteria from air samples also showed similar results with dominance of Actinobacteria and Proteobacteria in both hog farm and spray field air. Thus, the existence of opportunistic pathogens and antibiotic resistant bacteria in airborne communities evidences potential health risks to farmers and other residents from swine bioaerosol exposure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.339-344
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• 2011

We investigated the effects of enrichment with oil or bacteria on the fatty acid composition of rotifers and Artemia as live prey. One enrichment(oil source) was mainly composed of squid Todarodes pacificus liver oil; the other(photosynthetic-bacterial source) was primarily made up of Schizochytrium sp. The enrichments were intended to enhance the nutritional value of the live prey, such as their EPA, DHA and n-3 HUFA contents. The lipid content as EPA and DHA of rotifers was higher when enriched with the oil source rather than the photosynthetic-bacterial source. The DHA content of Artemia nauplii after enrichment differed significantly, depending on the type of enrichment used(P<0.05). When the Artemia nauplii were enriched with the oil source, the DHA content was increased to 16.8%, whereas it increased only to 1.1% when enriched with the photosynthetic-bacterial source. These results indicate that selection of the enrichment is important for Artemia nauplii but not for rotifers.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.44-49
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• 2003

Effects of supplementation with ruminal epithelial cells on fiber-degrading activity and cell growth of Ruminococcus albus (R. albus, strain 7) was tested using a basal substrate of rice straw and formulated concentrate. Cultures of R. albus alone and R. albus with rumen protozoa were grown at $39^{\circ}C$ for 48 h with an 8.4% crude protein (CP) substrate, 33% of the CP supplemented with either ruminal epithelial cells or defatted soybean meal. The ruminal epithelial cells had lower amounts of rumen soluble and degradable protein fractions as compared to defatted soybean meal, as determined by an enzymatic method, and the same was found with amino acid composition of protein hydrolysates. Ruminal epithelial cells were directly utilized by the R. albus, and resulted in greater growth of cell-wall free bacteria compared to defatted soybean meal. The effect of epithelial cells on bacterial growth was enhanced by the presence of rumen protozoa. In consistency with cultures of R. albus and R. albus with rumen protozoa, fermentative parameters such as dry matter degradability and total volatile fatty acid did not differ between supplementation with ruminal epithelial cells or defatted soybean meal.

• Journal of the Korean Society of Tobacco Science
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• v.14 no.2
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• pp.97-103
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• 1992

KB 101 is a bacterial wilt(Pseudomonas solanaceamm E.F. Smith) and black shank (Phytophthora nicotianae Breda de Haan Var. nicotianae Waterhouse) resistant cultivar of burley tobacco (Nicotiana tabacum L.) KB 101 was developed by the Korea Ginseng&Tobacco Research Institute, and released in 1987. KB 101 was developed from a single plant selection in the F2 generation derived from the double cross, [(Burley 21X Burley 37) X (Burley 64X Ky 16)]. Burley 37 and Burley 64 were the source of resistance to bacterial wilt and black shank. Yield trials were conducted in the Fs through F6 generations at the four Exp. Stn. of Korea Ginseng &Tobacco Research Institute as JB 7705-1. On-farm yield trials were conducted in the F7 through F9 generations at the 45 locations of burley tobacco growing area from 1984 to 1986 as KB 101. KB 101 has an erect growth habit similar to that of Burley 21: plant size is larger and has more leaves than those of Burley 21. It is late maturing cultivar that flowers approximately 3 days later than Burley 21. The physical characteristics and chemical composition of KB 101 were similar to those of Burley 21.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.990-996
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• 2005

The effect of diets varying in level and source of nitrogen (N) and fermentable organic matter on dynamic characteristics of microbial populations in rumen liquor and their impact on substrate fermentation in vitro was studied. The diets tested were straw alone, straw+concentrate mixture and straw+urea molasses mineral block (UMMB) lick. The same diets were taken as substrates and tested on each inoculum collected from the diets. Diet had no effect on the amino acid (AA) composition of either bacteria or protozoa. Differences among the diets in intake, source of N and OM affected bacterial and protozoal characteristics in the rumen. Upper asymptote of gas production (Y$\alpha$) had a higher correlation with bacterial pool size and production rate than with protozoal pool size and production rate. Among the parameters of the gas production model, Y$\alpha$ and lag time in total gas has showed significant (p<0.01) correlation with bacterial characteristics. Though the rate constant of gas production significantly differed (p<0.01) between diet and type of straw, it was least influenced by the microbial characteristics. The regression coefficient of diet and type of straw for Y$\alpha$ indicated that the effect of diet on Y$\alpha$ was threefold higher than that of the straw. As microbial characteristics showed higher correlation with Y$\alpha$, and diet had more influence on the microbial characteristics, gas production on a straw diet could be used effectively to understand the microbial characteristics.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.161-166
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• 1991

For the production of useful products from microorganism, a bacterial strain producing the biopolymer was isolated from soil. The bacteriological characteristics of the strain were examined and some chemical properties of the biopolymer produced were investigated. The bacterial strain was identified as an alkali-tolerant Bacillus sp. The results of chemical composition, various color reactions and I.R. spectrum revealed that the biopolymer contained high protein content, low amino sugar and no uronic acid. However, the biopolymer was precipitated by treating with cetylpiridinium chloride and was found to be acidic.

• Mycobiology
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• v.36 no.1
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• pp.40-44
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• 2008

Various bacteria were isolated from the casing layer soil of the culture bed of P. ostreatus and their role in fruiting body induction of the edible mushroom, P. ostreatus, was investigated. Analysis of the bacterial community isolated from the casing layer soil revealed that the composition of genera and number of cultivable bacteria were different for each sterilizing treatment. Bordetella was predominant in the bulk soil whereas Flavobacterium was predominant after sterilization of the casing layer soil. Fluorescent Pseudomonas was predominant in the non-sterilized casing layer soil. Total number of the bacterial genera in the casing layer soil was higher than that in the bulk soil. In particular, an increase in the fluorescent Pseudomonas population was observed in the non-sterilized casing layer accompanied by induction of fruiting body and enhanced mushroom production yield. The results suggested that specific bacterial populations in the casing layer play an important role in the formation of primodia and the development of basidiome in P. ostreatus.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1473-1483
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• 2014

Reports of herbicide resistance events are proliferating worldwide, leading to new cultivation strategies using combinations of pre-emergence and post-emergence herbicides. We analyzed the impact during a one-year cultivation cycle of several herbicide combinations on the rhizobacterial community of glyphosate-tolerant Bt-maize and compared them to those of the untreated or glyphosate-treated soils. Samples were analyzed using pyrosequencing of the V6 hypervariable region of the 16S rRNA gene. The sequences obtained were subjected to taxonomic, taxonomy-independent, and phylogeny-based diversity studies, followed by a statistical analysis using principal components analysis and hierarchical clustering with jackknife statistical validation. The resilience of the microbial communities was analyzed by comparing their relative composition at the end of the cultivation cycle. The bacterial communites from soil subjected to a combined treatment with mesotrione plus s-metolachlor followed by glyphosate were not statistically different from those treated with glyphosate or the untreated ones. The use of acetochlor plus terbuthylazine followed by glyphosate, and the use of aclonifen plus isoxaflutole followed by mesotrione clearly affected the resilience of their corresponding bacterial communities. The treatment with pethoxamid followed by glyphosate resulted in an intermediate effect. The use of glyphosate alone seems to be the less aggressive one for bacterial communities. Should a combined treatment be needed, the combination of mesotrione and s-metolachlor shows the next best final resilience. Our results show the relevance of comparative rhizobacterial community studies when novel combined herbicide treatments are deemed necessary to control weed growth.

• Microbiology and Biotechnology Letters
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• v.47 no.2
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• pp.303-309
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• 2019

Earlier studies by our group revealed that gallic acid in phytochemicals stimulated biofilm production in epiphytes, while caffeic acid in phytochemicals inhibited biofilm production in non-epiphytes. It is well documented that antimicrobial secretion by some epiphytic bacteria inhibits non-epiphytic bacterial growth on leaf surfaces. These selection criteria help plants choose their microbial inhabitants. Calcium and iron in phytochemicals also stimulate biofilm formation and thus, may be selection criteria adopted by plants with respect to their native epiphytic population. Furthermore, the processing of leaves during phytochemical extraction impacts the composition of the extract, and therefore its ability to affect bacterial biofilm formation. Computation of the Hurst exponent using biofilm thickness data obtained from the Ellipsometry of Brewster Angle Microscopic (BAM) images is an efficient tool for understanding the impact of phytochemicals on epiphytic and non-epiphytic populations when compared to fluorescent microscopy, scanning electron microscopy, and staining techniques. To the best of our knowledge, this is the first report that uses the Hurst exponent to elucidate the mechanism involved in plant microbe interaction.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.515-522
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• 2021

Jeotgal is a salty and fermented traditional Korean fish sauce. Unlike most other previous studies that investigated samples purchased from retail markets, this study focused on samples of jeotgal with traceable history to Yeonggwang, a timehonored fishing village in Korea. Three jeotgal samples, which were made from small yellow croakers, largehead hairtail, and miscellaneous fish, were selected based on information obtained from interviews with local craftsmen and literature reviews. Bacterial community profiles of the three jeotgal samples were investigated to identify indicator (and potentially core) bacteria for jeotgal ripening. The 16S rRNA gene-based metagenomic analysis revealed that the dominant phyla and classes, (Gammaproteobacteria, Betaproteobacteria, Bacilli, and Clostridia) of the three different jeotgal were identical, albeit with different composition ratios. Diversification was evident beginning at the order level. Interestingly, each dominant order was mainly comprised of single members even at the genus level. The dominant genera included Halomonas, Tetragenococcus, Halanaerobium, Pseudomonas, Massilia, and Lentibacillus. This observed genus-level heterogeneity suggests that there are diverse bacterial signatures in jeotgal and that these can be used as indicators for jeotgal ripening and/or as starters to increase its sensory quality and functionality.