• The Korean Journal of Mycology
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• v.49 no.2
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• pp.199-209
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• 2021

The present study was performed to improve the technique used for fermenting the mushroom growth medium. Taxonomic analysis of 16S rDNA sequence from the predominant Bacillus strain CY-24 isolated during the fermentation phase of the rice straw medium identified it as Bacillus licheniformis. In addition, the growth environment of B. licheniformis was also examined in this study, which revealed the optimal growth temperature and pH to be 30 ℃ and 6.0, respectively. This study also revealed that carboxymethyl cellulase (CMCase) and polygalacturonase (PGase) enzymes isolated from B. licheniformis achieved their maximal activities at 50 ℃ and 60 ℃ respectively. Furthermore, the study confirmed that the two enzymes, i.e., CMCase and PGase in B. licheniformis are stable at temperatures above 60 ℃. The present study thus demonstrates that B. licheniformis CY-24 possesses excellent enzymatic properties. It also reveals that the action of enzymes during the production of growth mediums used for the cultivation of mushrooms is closely associated with the promotion of fermentation and softening of the rice straw. Overall, this study provides elementary information regarding the role of B. licheniformis enzymes during growth medium fermentation for Agaricus bisporus cultivation.

• Journal of Marine Life Science
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• v.8 no.1
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• pp.43-49
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• 2023

This study applied a metagenomic analysis of the penguins' gut microbiome from fecal samples of Adélie Penguin (Pygoscelis adeliae) and Emperor Penguin (Aptenodytes forsteri) living along the Ross Sea, Antarctica. As a result of taxonomic analysis, 7 phyla and 18 families were mainly present in the gut microbiome of Adélie and Emperor penguins. To assess microbial diversity, we performed alpha diversity and OTU abundance analyses. It was confirmed that the Adélie Penguin's gut microbial species had a higher diversity than Emperor Penguin's. Based on the Beta diversity analysis using PCoA, differences were observed in the clustering between Adélie and Emperor penguins, respectively. Through the KEGG pathway analysis using PICRUSt, the nucleoside and nucleotide biosynthesis pathway was the most prevalent in Adélie and Emperor penguins. This study enabled a comparison and analysis of the composition and diversity of the gut microbiome in Adélie and Emperor Penguins. It could be utilized for future research related to penguin feeding habits and could serve as a foundation for analyzing the gut microbiomes of various other Antarctic organisms.

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.951-970
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• 2023

This study utilized Italian ryegrass silage (IRGS) - based total mixed ration (TMR) as feedstuff and evaluated its effects on rumen fermentation, growth performance, blood parameters, and bacterial community in growing Hanwoo heifers. Twenty-seven Hanwoo heifers (body weight [BW], 225.11 ± 10.57 kg) were randomly allocated to three experimental diets. Heifers were fed 1 of 3 treatments as follows: TMR with oat, timothy, and alfalfa hay (CON), TMR with 19% of IRGS (L-IRGS), and TMR with 36% of IRGS (H-IRGS). Feeding high levels of IRGS (H-IRGS) and CON TMR to heifers resulted in a greater molar proportion of propionate in the rumen. The impact of different TMR diets on the BW, average daily gain, dry matter intake, and feed conversion ratio of Hanwoo heifers during the growing period did not differ (p > 0.05). Furthermore, the blood metabolites, total protein, albumin, aspartate aminotransferase, glucose, and total cholesterol of the heifers were not affected by the different TMR diets (p > 0.05). In terms of rumen bacterial community composition, 264 operational taxonomic units (OTUs) were observed across the three TMR diets with 240, 239, and 220 OTUs in CON, L-IRGS, and H-IRGS, respectively. IRGS-based diets increased the relative abundances of genera belonging to phylum Bacteroidetes but decreased the abundances of genus belonging to phylum Firmicutes compared with the control. Data showed that Bacteroidetes was the most dominant phylum, while Prevotella ruminicola was the dominant species across the three TMR groups. The relative abundance of Ruminococcus bromii in the rumen increased in heifers fed with high inclusion of IRGS in the TMR (H-IRGS TMR). The relative abundance of R. bromii in the rumen significantly increased when heifers were fed H-IRGS TMR while P. ruminicola increased in both L-IRGS and H-IRGS TMR groups. Results from the current study demonstrate that the inclusion of IRGS in the TMR is comparable with the TMR containing high-quality forage (CON). Thus, a high level of IRGS can be used as a replacement forage ingredient in TMR feeding and had a beneficial effect of possibly modulating the rumen bacterial community toward mainly propionate-producing microorganisms.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.1
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• pp.48-55
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• 2009

Seasonal variations of microalgal biomass and community composition in both the sediment and the seawater were investigated by HPLC pigment analysis in an estuarine muddy sandflat of Gwangyang Bay from January to November 2002. Based on the photosynthetic pigments, fucoxanthin, diadinoxanthin, and diatoxanthin were the most dominant pigments all the year round, indicating that diatoms were the predominant algal groups of both the sediment and the seawater in Gwangyang Bay. The other algal pigments except the diatom-marker pigments showed relatively low concentrations. Microphytobenthic chlorophyll ${\alpha}$ concentrations in the upper layer (0.5 cm) of sediments ranged from 3.44 (March at the middle site of the tidal flat) to 169 (July at the upper site) mg $m^{-2}$, with the annual mean concentrations of $68.4{\pm}45.5,\;21.3{\pm}14.3,\;22.9{\pm}15.6mg\;m^{-2}$ at the upper, middle, and lower tidal sites, respectively. Depth-integrated chlorophyll ${\alpha}$ concentrations in the overlying water column ranged from 1.66 (November) to 11.7 (July) mg $m^{-2}$, with an annual mean of $6.96{\pm}3.04mg\;m^{-2}$. Microphytobenthic biomasses were about 3${\sim}$10 times higher than depth-integrated phytoplankton biomass in the overlying water column. The physical characteristics of this shallow estuarine tidal flat, similarity in taxonomic composition of the phytoplankton and microphytobenthos, and similar seasonal patterns in their biomasses suggest that resuspended microphytobenthos are an important component of phytoplankton biomass in Gwangyang Bay. Therefore, considering the importance of microphytobenthos as possible food source for the estuarine benthic and pelagic consumers, a consistent monitoring work on the behavior of microphytobenthos is needed in the tidal flat ecosystems.

• Korean Journal of Plant Resources
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• v.12 no.4
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• pp.312-323
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• 1999

External morphology, principal component analysis, cluster analysis, and vegetation were investigated to understand the taxonomic relationships and native environmental characters of Megaleranthis saniculifolia populations in four different habitats. Morphological characters such as calyx length and width, calyx index, presence or absence of serrate in calyx lobe, length of peduncle, branch of peduncle and fruit characters were useful for the identification of four different habitats. But, characters of plant height, bract and seed in four habitats were similar. The results obtained based on the principal component(PC) analysis of treated 96 OTU were divided into two groups by PC 1, 2, 3, and the sums of contributions for the total variance were 66.79%(PC1 31.3%, PC2 20.7%, PC3 15.8%, respectively), and only Mt. Taeki population was distinctly different from populations of other three habitats. In cluster analysis based on average linkage cluster analysis and Ward's method, there were similarities in the composition of clustered taxa, and each populations were not identified. Importance value by relative coverage and frequency appeared in M. saniculifolia(50.81%), Aruncus dioicus(12.64%), Corydalus turtschanovii(11.62%), Veratrum oxysepalum(11.45%), Anemone koraiensis(8.96%), Meehania urticifolia(8.76%), Filipendula palmata(7.06%), Aconitum pseudo-laeve(5.66%), Pseudostellaria palibiniana(5.45%) and Smilacina japonica(5.25%), respectively. These species were considered to be highly similar with M. saniculifolia. The highest importance value in all investigated sites was M. saniculifolia, but specific composition of high level different from each habitat. Average diversity of species was 1.40, and the highest in Mt. Kwangdeok(1.31), lowest in Mt. Jumbong(1.17). Average soil pH was 5.25 and similar in each habitat. Although the lowest content of K ion, but the highest the EC, water capacity, organic compound, Ca content were found in soil of Mt. Sobaek. Soils in Mt. Kwangdeok had the lowest content of EC, organic compound, Ca. Soils of Mt. Jumbong showed the highest of Mg content, but the lowest of water capacity, $P_2O_5$, and K contents.

• Korean Journal of Ichthyology
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• v.34 no.3
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• pp.186-200
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• 2022

In order to understand the species composition and distribution characteristics of larval assemblages in the East Sea, Korea, larvae were collected at 13 stations every other month from February to December 2018. Fish larvae were identified through DNA barcoding along with morphological methods, and as the result, a total of 104 taxonomic groups appeared during the survey. Among these, Engraulis japonicus, which accounted for 76.2% of the total population, was the most dominant species, followed by Maurolicus japonicus, which accounted for 15.0%. In addition, Ammodytes personatus, Champsodon snyderi, Scomber japonicus and Echelus uropterus appeared more frequently than other taxa. The above six species accounted for 93.2% of the total catch. The number of taxa and the amount of larvae collected in the survey area were higher during the high water temperature periods (June to October) than during the low water temperature periods (February, April and December). Analysis of similarity (ANOSIM) showed a statistically significant difference in monthly larval assemblages. The results of the canonical correspondence analysis (CCA) show that the distributions of larval community were mainly affected by sea surface temperature during low water temperature periods, and various environmental factors such as salinity, dry weight of zooplankton, and the concentrations of nutrients during high water temperature periods.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.2
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• pp.106-115
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• 2011

The aim of this study is to assess the importance of ballast water discharge as a vector for the introduction of exotic species into Pusan and Daesan Ports, Korea. We also examined to understand the impacts of environmental factors on the survival success of introduced species by ship's ballast water in laboratory experiments. Seven ship's ballast water originated from the coastal water of China (Taicang, Ningbo and Jinshan), Japan (Tokuyama, Moji and Akita), and Singapore. According to PCA (principal components analysis) analysis, environmental factor in the each ballast and shipside waters were different by bioregion. Based on cluster analysis, the phytoplankton community structures were distinguished for ballast water origin. Most of the major taxonomic groups were diatoms and, the others were dinoflagellate, silcoflagellate and several fresh-waters species. In particular, species number and standing crops of phytoplankton in the ballast tanks decreased with the increasing age ofballast water(r = -0.35 for standing crop; r = -0.63 for species number). In the laboratory study, although phytoplankton in ballast water treatment did not survive even in optimal temperature, the in vivo fluorescence of phytoplankton viability increased under the nutrient typical of shipside water and F/2 medium at $15^{\circ}C$ and $20^{\circ}C$. The diatoms species such as Skeletonema costatum and Thalassiosira pseudonana in ballast water were successfully regrown. On the salinity gradient experiments for Shui Shan (2) vessel, several freshwater species, brackish and marine species were successfully adapted. Of these, S.costatum was able to tolerate a wide range of salinities (10 to 30 psu) and its species-specific viability was suitable for colonization.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.4
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• pp.214-226
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• 2013

To understand the changing patterns in phytoplankton communities, we conducted 12 surveys along the Nakdong River, its estuary, and adjacent coastal areas between January 2011 and October 2012 (during the period of barrage construction and sediment dredging). Monthly precipitation ranged from 0 to 502 mm during the survey period, and salinity ranged between 0.1 psu and 0.3 psu in the Nakdong River, regardless of the depth, indicating no seawater influence, while salinity showed large seasonal fluctuations in the estuarine and coastal station, ranging from 0.1 psu to 34.8 psu. A total of 402 phytoplankton species were identified, 178 species from the river and 331 species from the estuary and coastal areas. Phytoplankton standing crop increased in 2012 compared to that in 2011, and was found to be highest in the river, followed by the estuary and coastal areas. Among the top 20 species in frequency of occurrence and dominance, Stephanodiscus spp., Aulacoseira granulata, and Aulacoseira granulata var. angustissima and Pseudo-nitzschia spp. were important species along the river-estuary-coastal areas. Diatoms were the major taxonomic group inhabiting the Nakdong river-estuary-coastal areas. A comparison of seasonal dominant phytoplankton species revealed a slight decrease over the years, from 13 species in 2011 to 10 species in 2012. However, no significant difference was found in the diversity of phytoplankton species between the two survey years, although lightly greater diversity was observed in the coastal areas than in the river and estuary. Cluster analysis with community composition data revealed that the community structure varied significantly in 2011 depending on the time of survey, while in 2012, it hardly showed any variation and was simpler. An increase in the phytoplankton standing crop, fewer dominant species, and simpler community structure in 2012 compared to those in 2011 are probably due to the rapid environmental changes along the Nakdong River. To investigate these ecological relationships, it is necessary to conduct further studies focusing on integrated analyses of biocenosis, including phytoplankton with respect to the changes in nutrient distribution, variation of freshwater discharge, and effect area of freshwater in the Nakdong estuary and adjacent coastal areas.

• Journal of Life Science
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• v.33 no.7
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• pp.565-573
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• 2023

In light of the complex interactions between the host animal and its resident gut microbiomes, studies of these microbial communities as a means to improve cattle production are important. This study was conducted to analyze the intestinal microorganisms of Holstein (HT) and Jersey (JS), raised in Korea and to clarify the differences in microbial structures according to cattle species through next-generation sequencing. The alpha-diversity analysis revealed that most species richness and diversity indices were significantly higher in JS than in HT whereas phylogenetic diversity, which is the sum of taxonomic distances, is not significant. Microbial composition analysis showed that the intestinal microbial community structure of the two groups differed. In the both groups, a significant correlation was observed among the distribution of several microbes at the family level. In particular, a highly significant correlation (p<0.0001) among a variety of microbial distributions was found in JS. Beta-diversity analyis was to performed to statistically verify whether a difference exists in the intestinal microbial community structure of the two groups. Principal coordinate analysis and unweighted pair group method with arithmetic mean (UPGMA) clustering analysis showed separation between the HT and JS clusters. Meanwhile, permutational multivariate analysis of variance (PERMANOVA) revealed that their microbial structures are significantly different (p<0.0001). LEfSe biomarker analysis was performed to discover the differenc microbial features between the two groups. We found that several microbes, such as Firmicutes, Bacilli, Moraxellaceae and Pseudomonadales account for most of the difference in intestinal microbial community structure between the two groups.