• Asian-Australasian Journal of Animal Sciences
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• 제27권11호
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• pp.1562-1570
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• 2014

The effects of Lactobacillus mucosae (L. mucosae), a potential direct fed microbial previously isolated from the rumen of Korean native goat, on the rumen fermentation profile of brewers grain were evaluated. Fermentation was conducted in serum bottles each containing 1% dry matter (DM) of the test substrate and either no L. mucosae (control), 1% 24 h broth culture of L. mucosae (T1), or 1% inoculation with the cell-free culture supernatant (T2). Each serum bottle was filled anaerobically with 100 mL of buffered rumen fluid and sealed prior to incubation for 0, 6, 12, 24, and 48 h from which fermentation parameters were monitored and the microbial diversity was evaluated. The results revealed that T1 had higher total gas production (65.00 mL) than the control (61.33 mL) and T2 (62.00 mL) (p<0.05) at 48 h. Consequently, T1 had significantly lower pH values (p<0.05) than the other groups at 48 h. Ammonia nitrogen ($NH_3$-N), individual and total volatile fatty acids (VFA) concentration and acetate:propionate ratio were higher in T1 and T2 than the control, but T1 and T2 were comparable for these parameters. Total methane ($CH_4$) production and carbon dioxide ($CO_2$) were highest in T1. The percent DM and organic matter digestibilities were comparable between all groups at all times of incubation. The total bacterial population was significantly higher in T1 (p<0.05) at 24 h, but then decreased to levels comparable to the control and T2 at 48 h. The denaturing gradient gel electrophoresis profile of the total bacterial 16s rRNA showed higher similarity between T1 and T2 at 24 h and between the control and T1 at 48 h. Overall, these results suggest that addition of L. mucosae and cell-free supernatant during the in vitro fermentation of dried brewers grain increases the VFA production, but has no effect on digestibility. The addition of L. mucosae can also increase the total bacterial population, but has no significant effect on the total microbial diversity. However, inoculation of the bacterium may increase $CH_4$ and $CO_2$ in vitro.

• 한국지구과학회지
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• 제28권4호
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• pp.497-540
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• 2007

지금까지 보고된 하부 오르도비스기의 Tremadocian과 Arenigian에 속하는 방산충 군집들 간에는 유사성이나 연관성이 거의 보이지 않았다. Tremadocian에서 Arenigian의 방산충 군집의 진화경향을 알 수 없었던 이유는 후기 Tremadocian 방산충 군집에 대해 알려진 바가 없었기 때문이다. 캐나다 뉴파운드랜드의 Cow Head Group에서 후기 Tremadocian에 속하는 방산충 화석 군집들이 처음으로 발견되었다. 이 새로운 방산충 군집들은 모두 6과, 11속, 26종에 속한다. 이들 가운데 6속 17종이 새로이 발견된 것들이다. Arenigian에서만 보고되었던 Proventocitidae에 속하는 종들이 다양하게 산출되었다. 초기 Tremadocian에 번성했던 Protoentactiniidae와 Echidniniidae에 속하는 것들은 감소하고 Aspiculumidae에 속하는 것들은 더욱 분화되어 다양하고 풍부하게 산출되었다. 방산충과 함께 출현하는 코노돈트 연구로 Low Diversity Interval에서 M. dianae Zone 그리고 하부 P. proteus Zone에 속하는 후기 Tremadocian 방산충 군집들로 밝혀졌다. 또한 R. manitouensis Zone에 속하는 코노돈트 화석군집이 발견되어 중기와 후기 Tremadocian에 속하는 Cow Head Group이 분포하는 여러 지역 간의 (Martin Point, Western Brook Pond, Broom Point, 그리고 St. Paul's Inlet) 층서대비를 보다 정확하게 할 수 있었고, 코노돈트 생층서에서는 R. manitouensis Zone, Low Diversity Interval, M. dianae Zone, 그리고 하부 P. proteus Zone이 식별되었다.

• Mycobiology
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• 제43권4호
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• pp.458-466
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• 2015

Oak tree death caused by symbiosis of an ambrosia beetle, Platypus koryoensis, and an ophiostomatoid filamentous fungus, Raffaelea quercus-mongolicae, has been a nationwide problem in Korea since 2004. In this study, we surveyed the yeast species associated with P. koryoensis to better understand the diversity of fungal associates of the beetle pest. In 2009, a total of 195 yeast isolates were sampled from larvae and adult beetles (female and male) of P. koryoensis in Cheonan, Goyang, and Paju; 8 species were identified by based on their morphological, biochemical and molecular analyses. Meyerozyma guilliermondii and Candida kashinagacola were found to be the two dominant species. Among the 8 species, Candida homilentoma was a newly recorded yeast species in Korea, and thus, its mycological characteristics were described. The P. koryoensis symbiont R. quercusmongolicae did not show extracelluar CM-cellulase, xylanase and avicelase activity that are responsible for degradation of wood structure; however, C. kashinagacola and M. guilliermondii did show the three extracellular enzymatic activities. Extracelluar CM-cellulase activity was also found in Ambrosiozyma sp., C. homilentoma, C. kashinagacola, and Candida sp. Extracelluar pectinase activity was detected in Ambrosiozyma sp., C. homilentoma, Candida sp., and M. guilliermondii. All the 8 yeast species displayed compatible relationships with R. quercus-mongolicae when they were co-cultivated on yeast extract-malt extract plates. Overall, our results demonstrated that P. koryoensis carries the yeast species as a symbiotic fungal associate. This is first report of yeast diversity associated with P. koryoensis.

• Animal Bioscience
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• 제37권1호
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• pp.84-94
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• 2024

Objective: The objective of this study was to investigate how cellulase or/and lactic acid bacteria (LAB) affected the fermentation characteristic and microbial community in wet brewer's grains (WBG) and corn stover (CS) mixed silage. Methods: The WBG was mixed thoroughly with the CS at 7:3 (w/w). Four treatment groups were studied: i) CON, no additives; ii) CEL, added cellulase (120 U/g fresh matter [FM]), iii) LAB, added LAB (2×10⁶ cfu/g FM), and iv) CLA, added cellulase (120 U/g FM) and LAB (2×10⁶ cfu/g FM). Results: All additive-treated groups showed higher fermentation quality over the 30 d ensiling period. As these groups exhibited higher (p<0.05) LAB counts and lactic acid (LA) content, along with lower pH value and ammonia-nitrogen (NH₃-N) content than the control. Specifically, cellulase-treated groups (CEL and CLA) showed lower (p<0.05) neutral detergent fiber and acid detergent fiber contents than other groups. All additives increased the abundance of beneficial bacteria (Firmicutes, Lactiplantibacillus, and Limosilactobacillus) while they decreased abundance of Proteobacteria and microbial diversity as well. Conclusion: The combined application of cellulase and LAB could effectively improve the fermentation quality and microbial community of the WBG and CS mixed silage.

• Journal of Forest and Environmental Science
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• 제33권2호
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• pp.79-90
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• 2017

Improving the urban environmental quality relies mainly on the increasing of urban forests capacity to store carbon dioxide. This study assesses the floristic diversity of urban institutional lands in Bukavu and their potential to reduce atmospheric $CO_2$. An exhaustive inventory over three sites ($Coll{\grave{e}}ge$ Alfajiri, $Cath{\acute{e}}drale$ Notre-Dame de la Paix and Institut $Sup{\acute{e}}rieur$ $P{\acute{e}}dagogique$) of Bukavu led to the identification of 1,113 trees of which the diameter at breast height (1.30 m) ranged from 4.9 to 161 cm. Results reveal a floristic diversity made up of 4 families of conifers with 4 species and 14 of broadleaves with 21 species. Average densities were of $54trees\;ha^{-1}$ and $5.21m^2\;ha^{-1}$ of basal area. Urban-based allometric equations used yielded up to 312.8 tons of carbon stored in trees aboveground biomass equivalent to 1,147.9 tons of $CO_2$ reduced from the atmosphere over the three sites. The rate of carbon storage reaches $15.1tons\;ha^{-1}$. Thus, trees of the three institutional sites in Bukavu play an important role in reducing atmospheric $CO_2$ and contribute, thereby, to mitigate global climate change effects. Given the current environmental challenge associated with high population growth rate in cities, the urban forest ecosystem in DRC requires to be extended and further investigation.

• Ecology and Resilient Infrastructure
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• 제9권2호
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• pp.100-106
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• 2022

섬진강 수계 210개 지방하천을 대상으로 하천연장과 보 밀도 대비 어류 출현종 현황을 분석하였다. 하천연장에 따른 어류 출현종수는 비선형지수함수 (Nonlinear exponential relationship) 관계를 보였다. 모델에 따른 계수값 (b)은 0.03이며, 결정계수(R²)은 약 59.0%인 것으로 나타났다. 모델식에 따른 예측기대종수는 실제 출현종수와 차이를 보였으며, 대상하천 가운데 약 110개 하천 (약 52.4%)에서 실제 출현종수는 예측기대종수보다 낮게 나타났다. 한편 섬진강 수계 하천에서 나타난 평균 보 밀도는 약 2.7개/km였으며, 이는 타 수계 하천과 비교시 월등히 높은 수치였다. 보 밀도 지표 (Index of Weir's Density, IWD)에 따른 어류출현종수간의 2-DKS 분석 결과 어류 다양성에 영향을 주는 보 밀도 역치값 (Threshold value)은 약 2.5개/km인 것으로 나타났다 (D_max=0.048, p<0.05). 실제 보 밀도 지표가 역치값 이상인 경우 어류 출현종수 대비 기대 종수비율은 70% 미만으로 낮아졌다. 따라서, 향후 수생태계 연속성 확보를 위한 보 밀도는 역치값 이하로 관리하는 것이 필요하다.

• Animal Systematics, Evolution and Diversity
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• 제36권4호
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• pp.309-315
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• 2020

The common rough woodlouse Porcellio scaber Latreille, 1804 is newly reported from South Korea with following diagnostic characteristics: the presence of distinct tubercles on body; the strongly developed lateral lobes of head; the presence of notch on tracheal field of pleopod 1 exopod; and distinctly short exopod of uropod. This species is reported to be cosmopolitan, but there were no taxonomic records of it in South Korea. All voucher specimens were collected from humid shaded areas adjacent to the eastern coast of South Korea. Organismal ecology and scanning electron microscope photographs are provided. In addition, the results of CO1 analysis of individuals representing the different color and morphological variations are provided.

• ALGAE
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• 제33권2호
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• pp.157-166
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• 2018

Cryptic species complexes are increasingly recognized in phycological research, obscuring taxonomy and raising questions about factors influencing speciation. A recent exploration of kelp genetic diversity on Haida Gwaii, British Columbia revealed the existence of a new species, Saccharina druehlii, which is cryptic with Saccharina sessilis. This suggests that molecular investigations further north may be required to elucidate the taxonomy and evolutionary history of this lineage. Although, for several decades, S. sessilis was considered a single highly variable species, its taxonomy has been far from straightforward. In particular, Hedophyllum subsessile (Areschoug) Setchell is now recognized as a synonym of S. sessilis in North America, but as a growth form of Saccharina bongardiana in Far East Russia. To resolve this taxonomic confusion, we sequenced mitochondrial (CO1-5P) and nuclear (internal transcribed spacer) markers of S. sessilis populations from the Aleutian Islands, Alaska, USA. Interestingly, none of our sequences matched S. sessilis sensu stricto. Instead, CO1-5P sequences from populations in the central and eastern Aleutians matched exactly S. druehlii with increasing sequence divergence occurring westward. Samples from Attu, the western-most island, composed a genetic group that clearly represents Kjellman's concept of Hafgygia bongardiana f. subsessilis and is distinct enough from S. druehlii and S. sessilis to potentially constitute a distinct species. Therefore, Saccharina subsessilis comb. nov. is proposed for this entity. Our results suggest the existence of a species complex at the crown node of S. sessilis and thus further investigation of Saccharina in Alaskan waters should be conducted to reconstruct the evolutionary history of this fascinating lineage.

• Journal of Ginseng Research
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• 제46권3호
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• pp.464-472
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• 2022

Background: Gut microbiota influence the central nervous system through gut-brain-axis. They also affect the neurological disorders. Gut microbiota differs in patients with Alzheimer's disease (AD), as a potential factor that leads to progression of AD. Oral intake of Korean Red Ginseng (KRG) improves the cognitive functions. Therefore, it can be proposed that KRG affect the microbiota on the gut-brain-axis to the brain. Methods: Tg2576 were used for the experimental model of AD. They were divided into four groups: wild type (n = 6), AD mice (n = 6), AD mice with 30 mg/kg/day (n = 6) or 100 mg/kg/day (n = 6) of KRG. Following two weeks, changes in gut microbiota were analyzed by Illumina HiSeq4000 platform 16S gene sequencing. Microglial activation were evaluated by quantitative Western blot analyses of Iba-1 protein. Claudin-5, occludin, laminin and CD13 assay were conducted for Blood-brain barrier (BBB) integrity. Amyloid beta (Aβ) accumulation demonstrated through Aβ 42/40 ratio was accessed by ELISA, and cognition were monitored by Novel object location test. Results: KRG improved the cognitive behavior of mice (30 mg/kg/day p < 0.05; 100 mg/kg/day p < 0.01), and decreased Aβ 42/40 ratio (p < 0.01) indicating reduced Aβ accumulation. Increased Iba-1 (p < 0.001) for reduced microglial activation, and upregulation of Claudin-5 (p < 0.05) for decreased BBB permeability were shown. In particular, diversity of gut microbiota was altered (30 mg/kg/day q-value<0.05), showing increased population of Lactobacillus species. (30 mg/kg/day 411%; 100 mg/kg/day 1040%). Conclusions: KRG administration showed the Lactobacillus dominance in the gut microbiota. Improvement of AD pathology by KRG can be medicated through gut-brain axis in mice model of AD.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.793-796
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• 2003

The electronics of a mobile robot ill nuclear facilities is required to satisfied the reliability to sustain survival in its radiation environment. To know how much radiation the robot has been encountered to replace sensitive electronic parts, a dosimeter to measure total accumulated dose is necessary. Among many radiation dosimeters or detectors, semiconductor radiation sensors have advantages in terms of power requirements and their sires over conventional detectors. This paper describes the use of the radiation-induced threshold voltage change of a commercial power pMOSFET as an accumulated radiation dose monitoring mean and that of the photo-current of a commercial PIN Diode as a dose-rate measurement mean. Commercial p-type power MOSFETs and PIN Diodes were tested in a Co-60 gamma irradiation facility to see their capabilities as radiation sensors. We found an inexpensive commercial power pMOSFET that shows good linearity in their threshold voltage shift with radiation dose and a PIN diode that shows good linearity in its photo-current change with dose-rate. According to these findings, a radiation hardened hybrid electronic radiation dosimeter for nuclear robots has been developed for the first time. This small hybrid dosimeter has also an advantage in the point of view of reliability improvement by using a diversity concept.