• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.156-168
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• 2024

This study was carried out to provide fundamental data for forest land and the environment by investigating the vegetation structure and soil properties of forest land where Sarcodon impricatus are present. The study area was divided into the Quercus mongolica community, dominated by Q. mongolica and the Quercus variabilis community, a mixed forest with Q. variabilis, Q. mongolica and Pinus densiflora. Also, Calamagrostis arundinacea in the former community and Disporum smilacinum and Carex siderosticta in the latter community showed significant levels as indicator species. Both communities showed a strong correlation between available phosphate and pH, sand, and clay, and the high organic matter content and slightly acidic pH of the soil are believed to be related to the development of S. impricatus. The species appearing at the lower layer continue to dominate because the species appearing at the upper layer have secured realized niches. The site was distributed in a relatively humid place in a north-east direction, and soil was developed with a thin litter layer and low rock exposure. In the selected S. impricatus growing areas, vegetation centered on highly adaptable species to disturbance or external interference was developed. Therefore, it is expected to be used as fundamental data to promote the occurrence of S. impricatus during artificial cultivation, as it is possible to identify the stand where S. impricatus occurs indirectly.

• Journal of Environmental Health Sciences
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• v.50 no.2
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• pp.93-101
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• 2024

Background: As pollutants caused by non-point sources flow into rivers, river water quality monitoring for fecal pollution is becoming increasingly important. Objectives: This study was conducted to investigate the distribution of microbial communities in the Yeongsangang River water system and sewage treatment plants in Gwangju and to evaluate their antibiotic resistance. Methods: In the experiment, samples were distributed to five selective media at each point and then cultured for 18 to 24 hours. When bacteria were observed, they were sub-cultured by size and shape and identified using MALDI-TOF MS equipment. When identification was completed, 17 types of antibiotic susceptibility tests were performed using VITEK II equipment, focusing on gram-negative dominant species among the identified strains. Results: During the study period, a total of 266 strains were isolated from 39 samples. Gram-positive bacteria were 37 strains in four genera, or 13.9% of the total, and Gram-negative bacteria were 229 strains in 23 genera, or 86.1% of the total. Antibiotic susceptibility testing of 23 strains, the major dominant species, showed that one strain (4.3%) was resistant to only one antibiotic, and two strains (8.7%) were 100% susceptible to the 17 antibiotics tested. The other 20 strains (87.0%) were multidrug resistant bacteria resistant to two or more antibiotics. There were various types of multidrug resistance. Among them, penicillin and cephalosporin series showed the highest resistance. Conclusions: Based on the results of this study, it was found that the bacterial community structure changed according to regional and environmental factors, and it was judged that continuous research such as genetic analysis of antibiotic-resistant bacteria present in natural rivers is necessary.

• Korean Journal of Veterinary Research
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• v.64 no.2
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• pp.17.1-17.10
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• 2024

This study examined the colostrum nutritive composition, immunoglobulin (Ig), and microbial community in Holstein and Jersey dairy cows according to the time after calving. The experiment used seven Holstein and three Jersey dairy cows. Colostrum was collected immediately after calf calving, 12, and 24 hours, and stored at -80℃ until analysis. An analysis of the nutritive composition in colostrum was performed using LactoScop. The immune indicators were analyzed using an ELISA Kit, and the microbial community was assessed using a Macrogen Inc. The protein level was high in all colostrum samples from Holstein dairy cows compared with Jersey dairy cows, but there was no significant difference according to the time after calving. Immune index analysis revealed high IgG and IgA concentrations in the colostrum of Holstein cows immediately after calving and 12 and 24 hours after calving, but the differences were not significant. The microbial community at the genus level revealed Staphylococcus to be predominant at a high rate in the colostrum of Holstein dairy cows and Enterococcus in Jersey dairy cows 12 hours after calving. Pseudomonas was predominant at a high rate in the colostrum of Jersey lactating cows immediately and 12 hours after calving. Chryseobacterium was predominant at a high rate in Holstein dairy cows 12 and 24 hours after calving. In conclusion, these results are expected to be used as research data on the correlation between quality, immunity, and microbial community in the colostrum.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.549-560
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• 2002

This study, including two in vitro experiments and an in vivo experiment were conducted to evaluate effects of Passtein$^{(R)}$ on crude protein degradability, ruminal fermentation characteristics and nutrient digestibility. In in vitro experiment protein degradability was examined using borate-phosphate buffer and neutral detergent, and using protease from Stroptomyces griseus at 39$^{\circ}C$ for 0, 2, 4, 8, 12, and 48 h. In addition, an in vivo experiment was conducted in a switch back design and ruminal fermentation and nutrient digestibility were determined. Four ruminal-fistulated Holstein cows weighing 300kg in mean body weight randomly allotted to 2 treatments (control and Passtein$^{(R)}$ supplementation). Although there was no significant difference on protein fraction between treatments, it appears that Passtein$^{(R)}$ supplementation decreased buffer soluble protein fraction compared to control. Protein degradability was not affected by Passtein$^{(R)}$ from 0 h to 4 h, but decreased at 12 h and 48 h compared to control. Degradation of immediately degradable fraction was higher in Passtein$^{(R)}$ treatment, but degradation of fermentable fraction was lower in Passtein$^{(R)}$ treatment compared to control. The pH and $NH_3$-N concentration tended to increase in Passtein$^{(R)}$ treatment, but VFA production, microbial counts and enzyme activity tended to decrease in Passtein$^{(R)}$ treatment compared to control. In addition, nutrient digestibility in the total tract tended to increase in Passtein$^{(R)}$ treatment compared to control.

• Food Science and Preservation
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• v.21 no.4
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• pp.512-519
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• 2014

This study was carried to investigate the physicochemical and microbiological characteristics of seasonal salted-Kimchi cabbage order to provide basic data for optimal salting and storage condition of seasonal Kimchi cabbage. Generally, fall season samples had slightly higher pH and acidity value than the other seasonal salted Kimchi cabbage. The soluble solids content of spring, summer, fall and winter samples were 5.95%, 6.18%, 6.29% and 7.76%, respectively. The salt content of all the seasonal salted Kimchi cabbage samples were insignificant. The number of microbial bacteria in the summer samples were generally much more significant than spring and winter samples. There was no significant difference in the color of seasonal salted Kimchi cabbage. As for the texture properties, the firmest samples in the surface rupture test were the spring samples (force: 4.92 kg), and the hardest samples in the puncture test were the summer samples (force: 11.71 kg). In the correlation analysis of the quality characteristics of seasonal samples, the soluble solids content and hardness of the seasonal salted Kimchi cabbage was significantly correlated at 1% significance level. Also, in the principal component analysis, F1 and F2 were shown to explain 27.28% and 35.59% of the total variance (62.87%), respectively. The hierarchical cluster analysis of the quality characteristics of seasonal samples, the samples were divided into three groups: spring cabbage group, summer cabbage group and fall and winter cabbage group.

• Journal of Life Science
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• v.31 no.3
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• pp.330-337
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• 2021

This study was conducted to investigate the potential of Stewartia koreana as oral healthcare materials. The antibacterial activity of ethanol extracts from leaves and branches of S. koreana against oral bacteria was confirmed. The leaf and branch extracts (1 mg/disc) showed antibacterial activity against P. gingivalis only among several tested oral bacteria. The leaf extracts showed higher antibacterial activity, with values similar to those of chlorhexidine, which was used as a positive control. The MIC of the leaf extract against P. gingivalis was 0.4 mg/ml and showed bacteriostatic action. The inhibitory effects of the extract on biofilm formation and on gene expression related to biofilm formation by P. gingivalis were determined by biofilm biomass staining, scanning electron microscopy (SEM), and qRT-PCR analysis. The biofilm production rate and cell growth of P. gingivalis in the cultures treated with 0.2-2.0 mg/ml of S. koreana leaf extracts were significantly decreased in a concentration-dependent manner. The inhibitory effect on the formation of P. gingivalis biofilms at concentrations of 1 mg/ml was confirmed by SEM. The qRT-PCR analysis showed concentration-dependent suppression of the fimA and fimB gene expression associated with fimbriae formation in the cultures treated with 0.2-2.0 mg/ml S. koreana leaf extract. These results support the conclusion that S. koreana leaf extracts can be used as oral healthcare materials derived from natural materials, as demonstrated by the antibacterial action and inhibition of biofilm formation of P. gingivalis.

• Restorative Dentistry and Endodontics
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• v.36 no.6
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• pp.498-505
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• 2011

Objectives: The purpose of this in vivo study was to investigate the microbial diversity in symptomatic and asymptomatic canals with primary endodontic infections by using GS FLX Titanium pyrosequencing. Materials and Methods: Sequencing was performed on 6 teeth (symptomatic, n = 3; asymptomatic, n = 3) with primary endodontic infections. Amplicons from hypervariable region of the small-subunit ribosomal RNA gene were generated by polymerized chain reaction (PCR), and sequenced by means of the GS FLX Titanium pyrosequencing. Results: On average, 10,639 and 45,455 16S rRNA sequences for asymptomatic and symptomatic teeth were obtained, respectively. Based on Ribosomal Database Project Classifier analysis, pyrosequencing identified the 141 bacterial genera in 13 phyla. The vast majority of sequences belonged to one of the seven phyla: Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria, Proteobacteria, Spirochetes, and Synergistetes. In genus level, Pyramidobacter, Streptococcus, and Leptotrichia constituted about 50% of microbial profile in asymptomatic teeth, whereas Neisseria, Propionibacterium, and Tessaracoccus were frequently found in symptomatic teeth (69%). Grouping the sequences in operational taxonomic units (3%) yielded 450 and 1,997 species level phylotypes in asymptomatic and symptomatic teeth, respectively. The total bacteria counts were significantly higher in symptomatic teeth than that of asymptomatic teeth (p < 0.05). Conclusions: GS FLX Titanium pyrosequencing could reveal a previously unidentified high bacterial diversity in primary endodontic infections.

• Journal of Life Science
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• v.24 no.10
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• pp.1110-1117
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• 2014

Tidal flats are continuously contaminated by human activities. This study assessed the bioremediation efficiency of tidal flat soil using microcosm reactors and microorganisms originating from the tidal area. We screened 135 bacterial strains that produce extracellular enzymes from the tidal area located in the North port of Incheon bay. Two bacterial strains (Pseudoalteromonas sp. and IC35 Halothiobacillus neapolitanus IC_S22) were selected and used in the microcosm reactors, which were specially designed to functionally mimic the ecological conditions of the tidal flats. Pseudoalteromonas sp. IC35 was selected based on its relatively high activity of the enzymes amylase, cellulose, lipase, and protease. Halothiobacillus neapolitanus IC_S22 was selected for oxidation of sulfur. The M1 and M2 microcosm reactors were operated by continuous feeding of seawater under the same conditions, but M2 was first inoculated with Pseudoalteromonas sp. IC35 before the seawater feeding. The initial COD in both the M1 and M2 microcosm reactors was 320 mg/l. The final COD was 21 mg/l (M1) and 7 mg/l (M2). The M3 and M4 microcosm reactors were operated by continuous feeding of seawater under the same conditions, but M4 was first inoculated with H. neapolitanus IC_S22. The initial sulfate concentration in both the M3 and M4 microcosm reactors was 660 mg/l, and the maximum sulfate concentration was 1,360 mg/l (M3) and 1,600 mg/l (M4).

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.85-96
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• 2023

The study involved the categorization of domestic lakes located in South Korea into three groups based on their salinity levels: upstream reservoirs with salinity less than 0.3 psu, estuarine reservoirs with salinity ranging from 0.3 to 2 psu, and brackish lagoons with salinity exceeding 2 psu. Subsequently, the research assessed variations in the concentrations of total nitrogen (T-N) and total phosphorus (T-P) in the sediment of these lakes using statistical analysis, specifically one-way analysis of variance (ANOVA). Additionally, a laboratory core incubation test was conducted to investigate the benthic nutrient fluxes in Songji lagoon (salinity: 11.80 psu), Ganwol reservoir (salinity: 0.73 psu), and Janggun reservoir (salinity: 0.08 psu) under both aerobic and anoxic conditions. The findings revealed statistically significant differences in the concentrations of T-N and T-P among sediments in the lakes with varying salinity levels (p<0.05). Further post-hoc analysis confirmed significant distinctions in T-N between upstream reservoirs and estuarine reservoirs (p<0.001), as well as between upstream reservoirs and brackish lagoons (p<0.01). For T-P, a significant difference was observed between upstream reservoirs and brackish lagoons (p<0.01). Regarding benthic nutrient fluxes, Ganwol Lake exhibited the highest diffusive flux of NH₄⁺-N, primarily due to its physical characteristics and the inhibition of nitrification resulting from its relatively high salinity. The flux of NO₃^--N was lower at higher salinity levels under aerobic conditions but increased under anoxic conditions, attributed to the impact of salinity on nitrification and denitrification. Additionally, the flux of PO₄^3--P was highest in Songji Lake, followed by Ganwol Lake and Janggun Reservoir, indicating that salinity promotes the diffusive flux of phosphate through anion adsorption competition. It's important to consider the influence of salinity on microbial communities, growth rates, oxidation-reduction processes, and nutrient binding forms when studying benthic diffusive nutrient fluxes from lake sediments.