• Journal of Microbiology
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• 제37권4호
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• pp.248-255
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• 1999

We have analyzed the MRE3/REC114 gene of Saccharomyces cerevisiae, previously detected in isolation of mutants defective in meiotic recombination. We cloned the MRE3/REC114 gene by complementation of the meiotic recombination defect and it has been mapped to chormosome XIII. The DNA sequence analysis revealed that the MRE3 gene is identical to the REC114 gene. The upstream region of the MRE3/REC114 gene contains a T_4C site, a URS (upstream repression sequence) and a TR (T-rich) box-like sequence, which reside upstream of many meiotic genes. Coincidentally, northern blot analysis indicated that the three sizes of MRE3/REC114 transcripts, 3.4, 1.4 and 1.2 kb, are induced in meiosis. A less abundant transcript of 1.4 kb is detected in both mitotic and meiotic cells, suggesting that it is needed in mitosis as well as meiosis. To examine the role of the MRE3/REC114 gene, we constructed mre3 disruption mutants. Strains carrying an insertion or null deletion of the MRE3/REC114 gene showed slow growth in nutrient medium and the doubling time of these cells increased approximately by 2-fond compared to the wild-type strain. Moreover, the deletion mutant (${\delta}$mre3) displayed no meiotically induced recombination and no viable spores. The mre3/rec114 spore lethality can be suppressed by spo13, a mutation that causes cells to bypass reductional division. The double-stranded breaks (DSBs) which are involved in initiation of meiotic recombination were not detected in the analysis of meiotic chromosomal DNA from the mre3/rec114 disruptant. From these results we suggest that the MRE3/REC114 gene product is essential in normal growth and in early meiotic stages involved in meiotic recombination.

• Parasites, Hosts and Diseases
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• 제46권3호
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• pp.153-156
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• 2008

One of the most common drugs used against a wide variety of anaerobic protozoan parasites is metronidazole. However, this drug is mutagenic for bacteria and is a potent carcinogen for rodents. Thymus vulgaris is used for cough suppression and relief of dyspepsia. Also it has antibacterial and antifungal properties. The aim of this study was to investigate antiamebic effect of Thymus vulgaris against Entamoeba histolytica in comparison with metronidazole. One hundred gram air-dried T. vulgaris plant was obtained and macerated at $25^{\circ}C$ for 14 days using n-hexane and a mixture of ethanol and water. For essential oil isolation T. vulgaris was subjected to hydrodistillation using a clevenger-type apparatus for 3 hr. E. histolytica, HM-1: IMSS strain was used in all experiments. It was found that the minimal inhibitory concentration (MIC) for T. vulgaris hydroalcoholic, hexanic extracts, and the essential oil after 24 hr was 4 mg/mL, 4 mg/mL, and 0.7 mg/mL, respectively. After 48 hr the MIC for T. vulgaris hydroalcoholic and hexanic extracts was 3 and 3 mg/mL, respectively. Therefore, it can be concluded that the Iranian T. vulgaris is effective against the trophozoites of E. histolytica.

• 비파괴검사학회지
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• 제32권5호
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• pp.484-493
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• 2012

초음파를 사용해 음속도, 감쇠 계수, 밀도, 비선형 B/A 파라미터 등을 측정하여 인체 조직의 특성을 정량적으로 영상화하고자 하는 연구가 1980년대부터 많이 진행되어 왔으나 아직 상용화 단계에는 도달하지 못했다. 하지만 1990년대 초에 시작된 탄성 영상법은 최근 들어 초음파 진단기에 상용화되어 임상에서 B-모드 영상법과 함께 전립선, 유방, 갑상선, 간, 혈관 등을 진단하기 위한 보완적이며 더 정량적인 모드로 사용되고 있는 단계에 진입하였다. 본고에서는 주로 준정적 또는 정적탄성 영상법에 사용되는 여러 가지 알고리듬을 소개하고 특성을 비교하고자 한다. 대부분의 알고리듬은 상호상관함수 또는 자기상관함수 방법에 그 기반을 두고 있으며 전자는 래그를 변화시켜가면서 시간 이동량을 찾지만 후자는 보간 과정 없이 고정된 래그에서의 위상차로부터 시간 이동량을 바로 구해 변위를 추정하는 점이다.

• 한국식품위생안전성학회지
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• 제19권1호
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• pp.25-30
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• 2004

숙주나물과 콩나물은 blanching후 변질 속도가 크게 차이가 나는 바 이들이 Bacillus subtilis, Bacillus cereus, Pseudomonas fluorescens, Listeria monocytogenes등 4종의 부패성 및 식중독 미생물의 증식에 미치는 영향을 조사하였다. 숙주나물과 콩나물의 조리과정 중 blanching조건이 달라 각각의 조건에서 두 시료 모두 blanching하여 생균수를 측정한 결과 blanching 한 후 미생물 수는 저장시간에 따라 증가하나 그 차이가 없었다. 최소배지에 숙주나물과 콩나물 농축물 및 부패성 미생물을 접종한 후 생균수를 측정한 결과 숙주나물에 접종한 모든 균들의 초기 균수가 높았으나 24시간 이후 비슷한 증식양상을 나타내었다. 그러나 숙주나물과 콩나물의 여액을 배지로 사용하여 실험한 결과 미생물의 증식 양상은 균주 마다 다른 것으로 나타났다. 저장기간 동안 색도를 측정한 결과 숙주나물의 경우 24시간에는 색차가 거의 없다가 48시간 이후 현저한 차이를 보였고, 콩나물의 경우 24시간에 다른 계통의 색으로 변하다가 48시간 이후 현저하게 많은 차이를 보여 다른 양상을 나타내었다.

• Restorative Dentistry and Endodontics
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• 제39권4호
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• pp.288-295
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• 2014

Objectives: This study was designed to evaluate the synergistic antibacterial effect of xylitol and ursolic acid (UA) against oral biofilms in vitro. Materials and Methods: S. mutans UA 159 (wild type), S. mutans KCOM 1207, KCOM 1128 and S. sobrinus ATCC 33478 were used. The susceptibility of S. mutans to UA and xylitol was evaluated using a broth microdilution method. Based on the results, combined susceptibility was evaluated using optimal inhibitory combinations (OIC), optimal bactericidal combinations (OBC), and fractional inhibitory concentrations (FIC). The anti-biofilm activity of xylitol and UA on Streptococcus spp. was evaluated by growing cells in 24-well polystyrene microtiter plates for the biofilm assay. Significant mean differences among experimental groups were determined by Fisher's Least Significant Difference (p < 0.05). Results: The synergistic interactions between xylitol and UA were observed against all tested strains, showing the FICs < 1. The combined treatment of xylitol and UA inhibited the biofilm formation significantly and also prevented pH decline to critical value of 5.5 effectively. The biofilm disassembly was substantially influenced by different age of biofilm when exposed to the combined treatment of xylitol and UA. Comparing to the single strain, relatively higher concentration of xylitol and UA was needed for inhibiting and disassembling biofilm formed by a mixed culture of S. mutans 159 and S. sobrinus 33478. Conclusions: This study demonstrated that xylitol and UA, synergistic inhibitors, can be a potential agent for enhancing the antimicrobial and anti-biofilm efficacy against S. mutans and S. sobrinus in the oral environment.

• 한국식품영양과학회지
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• 제33권5호
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• pp.791-796
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• 2004

본 연구에서는 아위버섯의 생리활성 기능규명을 목적으로 하였다 사람의 뇌세포에서의 아세틸콜린분해효소 억제효과는25∼35%의 경향을 보여 치매 예방 및 개선제로서의 가능성을 보였다. 유해산소 제거 기능은 35∼36%로 높아 항암, 노화, 심장병 등에 좋은 효과를 나타낼 수 있을 것으로 생각되어진다. 간섬유화(collagen type-I) 억 제는 3∼12%의 저해효과를 보였다. 그러나 아위버섯은 3∼8%의 포도당 흡수억제를 나타내어 당뇨와 비만억 제에 큰 효과를 보이지 않았으며, 위암과 대장암에 대한 항암효과도 거의 나타나지 않았다. 따라서 향후 아위버섯 추출물 특히, K8종에서 나타난 다양한 생리활성효과를 이용하여 고부가가치의 다양한 기능성제품이 가능할 것으로 판단된다

• 한국산림과학회지
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• 제78권4호
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• pp.372-380
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• 1989

주요(主要) 조림수종(造林樹種)의 하나인 현사시나무를 Agrobacterium rhizogenes의 agropine 계통(系統)인 A4를 이용(利用)하여 유전적(遺傳的)으로 형질전환(形質轉換)시켰다. 형질전환(形質轉換) 여부는 조직(組織)내의 opine(agropine) 존재를 분석(分析)하여 확인(確認)하였다. 형질전환(形質轉換)으로 얻어진 hairy root는 1/4MS+sucrose 30g/L에서 가장 좋은 생장(生長)을 보였으며, 식물체(植物體) 재분화(再分化)는 BAP 0.5mg/l를 첨가한 MS배지(培地)에 배양(培養)하였을 때 가장 좋은 결과(結果)를 얻었다. 재분화(再分化)된 식물체(植物體)는 뿌리가 많고 형태적(形態的)으로 변형(變形)되어 정상의 식물(植物)과 구별(區別)할 수 있었다. 부분적(部分的)으로 뿌리부분(部分)만 형질전환(形質轉換) 시킴으로써 보다 많은 뿌리를 가진 개체(個體)로 만들 수 있었고 이는 임목(林木)의 지상부(地下部) 형질개량(形質改良)에 유리(有利)한 것으로 나타났다.

• Smart Structures and Systems
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• 제7권4호
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• pp.303-317
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• 2011

A specially designed tendon, which is proposed by embedding an FBG sensor into the center king cable of a 7-wire strand tendon, was applied to monitor the prestress force and load transfer of ground anchor. A series of tensile tests and a model pullout test were performed to verify the feasibility of the proposed smart tendon as a measuring sensor of tension force and load transfer along the tendon. The smart tendon has proven to be very effective for monitoring prestress force and load transfer by measuring the strain change of the tendon at the free part and the fixed part of ground anchor, respectively. Two 11.5 m long proto-type ground anchors were made simply by replacing a tendon with the proposed smart tendon and prestress forces of each anchor were monitored during the loading-unloading step using both FBG sensor embedded in the smart tendon and the conventional load cell. By comparing the prestress forces measured by the smart tendon and load cell, it was found that the prestress force monitored from the FBG sensor located at the free part is comparable to that measured from the conventional load cell. Furthermore, the load transfer of prestressing force at the tendon-grout interface was clearly measured from the FBGs distributed along the fixed part. From these pullout tests, the proposed smart tendon is not only expected to be an alternative monitoring tool for measuring prestress force from the introducing stage to the long-term period for health monitoring of the ground anchor but also can be used to improve design practice through determining the economic fixed length by practically measuring the load transfer depth.

• International Journal of Industrial Entomology and Biomaterials
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• 제1권1호
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• pp.9-17
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• 2000

Genetic variation in the domestic silkworm strains (Bombyx mori) and phylogenetic relationships between domestic silkworms and wild silkworms (B. mandarina) were investigated by using a portion of mitochondrial CGI gene sequences. Ten geographic strains of B. mori we sequenced were identical in the 410 bp-section of mitochondrial COI gene. This sequence was also identical to the homologous sequence of the four Gen-Bank-registered strains, but one strain of B. mori differed a single nucleotide (0.2%) from others. MtDNA homogeneity in the B. mori strains appears to be resulted from fixation into the mast frequent mtDNA type during the course of breeding for new strains, in which an extensive indoor rearing and removal of unwanted individuals were accompanied. In the comparisons between domestic and wild silkworms, some wild silkworms were closely related to domestic silkworms (0.2%-1.2% of divergence), but the others were not (2.7%-3.7% of sequence divergence). This result was also reflected in the phylogenetic analyses, showing two independent phylogenetic groups: one including all B. mandarina sequences and the other including both B. mandarina and B. mori sequences. Thus, domestic silkworms may have been derived from the ancestor of B. mandarina, which belongs to this group, alto-ough more extensive study will provide better understanding on this issue.

• 국제초고층학회논문집
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• 제10권4호
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• pp.265-283
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• 2021

To ensure that fire induced collapse of a building is prevented it is important to understand the sequence of events that can lead to this event. In this paper, the initiation of collapse mechanisms of generic a multi-storey steel frame subjected to vertical and horizontal travelling fires are analysed computationally by tracking the formation of plastic hinges in the frame and generation of fire induced loads. Both uniform and travelling fires are considered. In total 58 different cases are analysed using finite element software LS-DYNA. For the frame examined with a simple and generic structural arrangement and higher applied fire protection to the columns, the results indicate that collapse mechanisms for singe floor and multiple floor fires can be each split into two main groups. For single floor fires (taking place in the upper floors of the frame (Group S1)), collapse is initiated by the pull-in of external columns when heated beams in end bays go into catenary action. For single floor fires occurring on the lower floors(Group S2), failure is initiated (i.e. ultimate strain of the material is exceeded) after the local beam collapse. Failure in both groups for single floor fires is governed by the generation of high loads due to restrained thermal expansion and the loss of material strength. For multiple floor fires with a low number of fire floors (1 to 3) - Group M1, failure is dominated by the loss of material strength and collapse is mainly initiated by the pull-in of external columns. For the cases with a larger number of fire floors (5 to 10) - Group M2, failure is dominated by thermal expansion and collapse is mainly initiated by swaying of the frame to the side of fire origin. The results show that for the investigated frame initiation of collapse mechanisms are affected by the fire type, the number of fire floors, and the location of the fire floor. The findings of this study could be of use to designers of buildings when developing fire protection strategies for steel framed buildings where the potential for a multifloor fire exists.