• Animal Bioscience
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• 제37권2_spc호
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• pp.360-369
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• 2024

Ruminal methane production functions as the main sink for metabolic hydrogen generated through rumen fermentation and is recognized as a considerable source of greenhouse gas emissions. Methane production is a complex trait affected by dry matter intake, feed composition, rumen microbiota and their fermentation, lactation stage, host genetics, and environmental factors. Various mitigation approaches have been proposed. Because individual ruminants exhibit different methane conversion efficiencies, the microbial characteristics of low-methane-emitting animals can be essential for successful rumen manipulation and environment-friendly methane mitigation. Several bacterial species, including Sharpea, uncharacterized Succinivibrionaceae, and certain Prevotella phylotypes have been listed as key players in low-methane-emitting sheep and cows. The functional characteristics of the unclassified bacteria remain unclear, as they are yet to be cultured. Here, we review ruminal methane production and mitigation strategies, focusing on rumen fermentation and the functional role of rumen microbiota, and describe the phylogenetic and physiological characteristics of a novel Prevotella species recently isolated from low methane-emitting and high propionate-producing cows. This review may help to provide a better understanding of the ruminal digestion process and rumen function to identify holistic and environmentally friendly methane mitigation approaches for sustainable ruminant production.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.531-541
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• 1996

Periodontal disease is characterized by destruction of supporting tissues caused by invasion of plaque bacteria and defense mechanism of host. Many dentists are very interested in laser therapy on various intraoral soft tissue lesions including inflammatory periodontal pocket. In order to determine the therapeutic effect of intrapocket irradiation of a pulsed- Nd : YAG laser on the inflammatory periodontal pockets, bilateral 60 teeth with 4-6mm in probing pocket depth and gingival inflammation were selected and evaluated by sulcus bleeding index(SBI), and plaque index(pI) for baseline record. Intrapocket irradiation($300{\mu}m$ fiber optic, I.5W power, for 2 min.) of a pulsed-Nd : YAG laser(EL.EN.EN060, Italy) was applied on half of them. As the control group, the same procedure except power-off was repeated on the contralateral 30 teeth. At 1-, 2-, 3-, and 4-week after intrapocket manipulation, every tooth was reevaluated by the same clinical indices. And the difference between the lased group and control group was statistically analyzed by paired t-test and Chi-square test in Microstat program. Following results were obtained: 1. Until I-week and 2-week after intrapocket manipulation, SBI was lowered in both lased group and control group, compared to baseline SBI, but from 3-week after, the recovering tendency toward baseline was noted, and at only 2-week after, the number of teeth showing lowered SBI was significantly more in lased group than in control group(p<0.05). 2. PI of both lased group and control group was lowered through whole experimental period from I-week to 4-week after, compared to baseline PI(p<0.05), but there was no significant difference between lased group and control group(p>0.1). The results suggest that intrapocket irradiation of a pulsed-Nd:YAG laser may lead somewhat remission of gingival inflammation, but for more favorable therapeutic result the thorough root planing should be necessarily accompanied with gingival curettage.

• The Plant Pathology Journal
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• 제25권3호
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• pp.286-290
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• 2009

The stability of three different kinds of pUC-derived plasmids, pDsRed, pZsYellow, and pGFPuv, was investigated in Pectobacterium strains to utilize those plasmids as tracers. All three plasmids pDsRed, pZsYellow and pGFPuv showed their specific colors in Pectobacterium strains. Especially, the plasmid pDsRed conferred bright pink colonies on the Pectobacterium strains. When the bacteria lost the plasmid pDsRed, the colonies turned white, suggesting that the plasmid could be a good marker system for Pectobacterium strains on different environmental conditions. The effect of the antibiotic pressure on the stability of the plasmid was different depending on the host bacteria. P. carotovorum subsp. betavasculorum was more sensitive to the antibiotic pressure than P. carotovorum subsp. carotovorum Pcc21. However, temperature change significantly affected plasmid stability on both Pectobacterium strains. Almost all strains lost the plasmids with the shift in temperature from $28^{\circ}C$ to $37^{\circ}C$. Presence of the plasmids did not affect bacterial pathogenicity on their own host plants. Among three plasmids, pZsYellow was not useful as a marker because the yellow fluorescent proteins from pZs Yellow were interfered with the yellow natural fluorescence of the plant tissues induced by the defense system. Since the red color of DsRed can be seen with naked eyes, plasmid pDsRed was applicable as a marker. However, the color change was slow so that additional manipulation to increase the expression speed was necessary. Plasmid pGFPuv could serve as a perfect marker without any problem, tracing the reproduction and spread of the plant pathogens perfectly.

• Asian-Australasian Journal of Animal Sciences
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• 제21권5호
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• pp.745-753
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• 2008

Gene-manipulated mice were discovered for the first time about a quarter century ago. Since then, numerous sophisticated technologies have been developed and applied to answer key questions about the fundamental roles of the genes of interest. Functional genomics can be characterized into gain-of-function and loss-of-function, which are called transgenic and knock-out studies, respectively. To make transgenic mice, the most widely used technique is the microinjection of transgene-containing vectors into the embryonic pronucleus. However, there are critical drawbacks: namely position effects, integration of unknown copies of a foreign gene, and instability of the foreign DNA within the host genome. To overcome these problems, the ROSA26 locus was used for the knock-in site of a transgene. Usage of this locus is discussed for the gain of function study as well as for several brilliant approaches such as conditional/inducible transgenic system, reproducible/inducible knockdown system, specific cell ablation by Cre-mediated expression of DTA, Cre-ERTM mice as a useful tool for temporal gene regulation, MORE mice as a germ line delete and site specific recombinase system. Techniques to make null mutant mice include complicated steps: vector design and construction, colony selection of embryonic stem (ES) cells, production of chimera mice, confirmation of germ line transmission, and so forth. It is tedious and labor intensive work and difficult to approach. Thus, it is not readily accessible by most researchers. In order to overcome such limitations, technical breakthroughs such as reporter knock-in and gene knock-out system, production of homozygous mutant ES cells from a single targeting vector, and production of mutant mice from tetraploid embryos are developed. With these upcoming progresses, it is important to consider how we could develop these systems further and expand to other animal models such as pigs and monkeys that have more physiological similarities to humans.

• 한국동물생명공학회지
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• 제34권3호
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• pp.247-252
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• 2019

We observed MMPs expression in all sperm groups, with pro-MMP showing lower expression than active MMPs. According to the results from each freezing extender, the sperm membrane integrity (HOST: Hypoosmotic Swelling Test) analysis in TCGGD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Glycerol 3%, Dimethylsulpoxide 3.5 M) is 59.8 ± 0.7, TCGSD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Sucrose 0.1 M, Dimethylsulpoxide 3.5 M) is 59.3 ± 0.5 were significantly higher (p < 0.05) among the experimental groups. And MMPs analysis result, we observed MMPs expression in all sperm groups, with pro-MMP showing lower expression than active MMPs. The expression of active MMP-2 was the highest in sperms frozen in TCGSD and TCGD (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Dimethylsulpoxide 3.5 M), Meanwhile, sperms from the TCGGD and TCGED (Tris 250 mM, Citric acid 88 mM, Glucose 47 mM, Ethylene glycol 3%, Dimethylsulpoxide 3.5 M) group showed lower level of active MMP-2 expression. Together, these results indicate that adding glycerol or sucrose to the sperm freezing buffer would not only suppress MMPs expression but also minimize DNA fragmentation, providing a mean to improve the success rate in the in vitro manipulation of rabbit sperms. Therefore, these results suggest that TCGGD or TCGSD extender method for freezing-thawing of rabbit sperm increased the viability after thawing.

• Asian-Australasian Journal of Animal Sciences
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• 제17권6호
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• pp.877-884
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• 2004

Although gut microbial functions have been analyzed through cultivation of isolated microbes, molecular analysis without cultivation is becoming a popular approach in recent years. Gene cloning studies have partially revealed the mechanisms involved in fiber digestion of individual microbe. The molecular approach finally made it possible to analyze full genomes of the representative rumen cellulolytic bacteria Fibrobacter and Ruminococcus. The coming database may contain useful information such as regulation of gene expression relating to fiber digestion. Meanwhile, unculturable bacteria are still poorly characterized, even though they are main constituents of gut microbial ecosystem. The molecular analysis is essential to initiating the studies on these unculturable bacteria. The studies dealing with rumen and large intestine are revealing considerable complexity of the microbial ecosystems with many undescribed bacteria. These bacteria are being highlighted as possibly functional members contributing to feed digestion. Manipulation of gut bacteria and gut ecology for improving animal production is still at challenging stage. Bacteria newly introduced in the rumen, whether they are genetically modified or not, suffer from poor survival. In one of these attempts, Butyrivibrio fibrisolvens expressing a foreign dehalogenase was successfully established in sheep rumen to prevent fluoroacetate poisoning. This expands choice of forages in tropics, since many tropic plants are known to contain the toxic fluoroacetate. This example may promise the possible application of molecular breeding of gut bacteria to the host animals with significance in their health and nutrition. When inoculation strategies for such foreign bacteria are considered, it is obvious that we should have more detailed information of the gut microbial ecology.

• 한국융합학회논문지
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• 제8권11호
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• pp.21-27
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• 2017

초연결사회를 지향하기 위해 발전하고 있는 사물인터넷(Internet of Things)은 아두이노 등의 OSHW(Open Source Hardware)를 기반으로 두고 있으며 다양한 소형 제품 등이 등장하고 있다. 이러한 사물인터넷은 저성능, 저메모리라는 한계로 인하여 강력한 보안 기술을 적용하기 어렵다는 심각한 정보보안 문제를 야기하고 있다. 본 논문에서는 사물인터넷 기기로 주로 사용되는 아두이노의 응용프로그램이 호스트컴퓨터에서 컴파일과 로딩이 수행됨에 따라 발생할 수 있는 취약성을 분석하여 아두이노 보드의 센서로부터 입력되는 값을 공격자가 임의로 변경할 수 있는 새로운 공격 방법을 제안한다. 이러한 방법을 통해 아두이노 보드가 환경정보를 오인식하여 정상적인 동작이 불가능하게 할 수 있다. 이러한 공격 기법의 이해를 통해 안전한 개발환경 구축방안을 고려할 수 있으며 이러한 공격으로부터 대응할 수 있다.

• 정보처리학회논문지C
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• 제10C권1호
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• pp.71-76
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• 2003

인터넷 사용자의 증가와 인터넷을 이용한 전자상거래(E-commerce)의 확산 그리고 네트워크 게임 등으로 인해 인터넷상의 사용자 데이터는 끊임없이 증가하고 있는 상태이다. 이러한 인터넷의 확산을 지원하기 위해 고속 통신을 가능하게 할 초고속 라우터가 상용화되는 추세이다. 고속의 패킷 라우팅 처리를 위해 고안된 라우터 구조를 살펴보면, 라인 인터페이스와 호스트 프로세서는 각각 제어용 프로세서를 가지고 있어 독립된 디바이스로 동작하며 패킷 스위칭과 고속의 패킷 포워딩, 신속한 FIB(Forwarding Information Base)처리 등을 구현하고 있다. 본 논문에서는 라우팅 정보를 관리하는 유니캐스트 및 멀티캐스트 라우팅 프로토콜과 OAM(Operation And Maintenance) 관련 패킷을 비포워딩(nonforwarding) 패킷으로 정의하고, 이를 처리하는 라인 인터페이스와 호스트 프로세서에서의 소프트웨어 구조를 제시하였다. 또한 분산 시스템에 요구되는 프로세서 간의 통신 메커니즘으로 프로세서간 통신 처리용 프로토콜(Inter-Processor Communication Message Protocol)을 설계 및 적용하여 기존의 UDP/IP를 이용하는 통신 메커니즘에 비해 성능이 향상됨을 확인하였다.

• 한국산림과학회지
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• 제59권1호
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• pp.121-142
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• 1983

Recently mycorrhizal research has been one of the most fast-growing research areas in modern plant science and microbiology. The application potential of mycorrhizal techniques to agriculture and forestry is enormous in view of the ubiquitous nature of mycorrhizae and known benefits of mycorrhizae to host plants. Unfortunately, very few scientists in Korea are currently involved in mycorrhizal research. When a team of American plant pathologists visited Korea in September 1982 to participate in the Korea-U.S.A. Joint Seminar on Forest Diseases and Insect Pests, they were surprised by the principal author's statement that there was no single research project on mycorrhizae sponsored by Korean government or any scientific institutions. The author initiated a few years ago a research project on the ecology of tree mycorrhizae with a foreign financial support. Major areas of interest were survey of ectomycorrhizae in relation to soil fertility, taxonomic distribution of mycorrhizae among woody plants, identification of ectomycorrhizal fungi, and growth response of woody plants to artificial inoculation. In spite of the enormous application potential of mycorrhizae to agronomic plants, the subject of mycorrhizae has not been recognized by Korean agronomists, foresters or pathologists. The purpose of this review rather written in Korean is to introduce the techniques of mycorrhizal research to Korean scientists and to urge them to participate in challenging new scientific field which might bring us a remarkable increase in crop productivity and tree growth through manipulation of this unique symbiosis. In this review, following topics were discussed in the same order: introduction; brief history of mycorrhizal research; morphology and classification of mycorrhizae; distribution of mycorrhizae in plant kingdom and in soil profile; physiology of mycorrhizae (functions, mineral nutrition, mycorrhizal formation); interaction of mycorrhizae with soil-born plant pathogens. mycorrhizae in nitrogen-fixing plants; application of mycorrhizal techniques to nursery practices (isolation, culture, inoculation, and response); prospect in the future.

• Journal of Animal Science and Technology
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• 제64권5호
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• pp.897-910
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• 2022

Bovine fecal microbiota is important for host health and its composition can be affected by various factors, such as diet, age, species, breed, regions, and environments. The objective of this study was to evaluate the impact of diet and gender on fecal microbiota in Korean native Hanwoo cattle. The 16S rRNA gene amplicon sequencing of fecal microbiota was conducted from 44 Hanwoo cattle divided into four groups: (1) 11 heifers fed an oat hay plus total mixed ration (TMR) diet for breeding (HOTB), (2) 11 heifers fed an early fattening TMR diet (HEFT), (3) 11 steers fed the early fattening TMR diet (SEFT), and (4) 11 steers fed the late fattening TMR diet (SLFT). Firmicutes and Bacteroidota were the first and second most dominant phyla in all the samples, respectively. The Firmicutes/Bacteroidota (F/B) ratio associated with feed efficiency was significantly greater in the SLFT group than in the other groups. At the genus level, Romboutsia, Paeniclostridium, and Turicibacter were the most abundant in the SLFT while Akkermansia, Bacteroides, and Monoglobus were the most abundant in the HOTB group. Although the same early fattening TMR diet was fed to Hanwoo heifers and steers, Marvinbryantia and Coprococcus were the most abundant in the HEFT group while Alistipes and Ruminococcus were the most abundant in the SEFT group. Shannon and Simpson diversity indices were significantly lower in the SLFT group than in the other groups. Distribution of fecal microbiota and functional genetic profiles were significantly different among the four treatment groups. The present study demonstrates that different diets and genders can affect fecal microbiota and the F/B ratio may be associated with feed efficiency in Hanwoo cattle. Our results may help develop strategies to improve gut health and productivity through manipulation of fecal microbiota using the appropriate diet considering Hanwoo cattle gender.