• 한국작물학회지
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• 제26권2호
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• pp.192-197
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• 1981

Alfalfa에 대한 국내분이 근유균의 유효성과 효과적인 근유균 접종방법을 밝히고져 배지상에서 이들 균주의 근유형성 및 질소고정능력을 검토한 다음 이들 균주에 3가지 종자접종방법을 적용하여 사경재배를 실시한 결과는 다음과 같다. 1. 근유균 접종에 따른 근유의 형성은 접종 2주후부터 볼 수 있었고 유묘의 생장은 대조구보다 현저히 증가되있으며 질업처리구(70ugN/ml)와 차이가 없어 두 균주는 모두 유교균주로 평가되었다. 2. 두 균주 모두 Broth-vacuum 방법으로 접종한 것은 근규의 형성은 있었으나 실험기간 중 유묘의 생장에 있어서는 무접종 대조구와 차이가 없었다. 3. Peat & lime pelleting 방법은 두 균주 모두에서 근유형성과 유묘생장을 현저히 증가시켰으나 Peat-adhesive 방법은$ A_1$ strain 에서 만 효과적이었다. 4. 근유의 무게와 지상부 건물중 그리고 근유의 무게와 근중사이에는 두 균주 모두에서 고도의 정의 상관관계가 인정되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제31권4호
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• pp.585-594
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• 2018

Objective: This study was to determine the bacterial diversity and monitor the community dynamic changes during storage of vacuum-packaged sliced raw beef as affected by Lactobacillus sakei and Lactobacillus curvatus. Methods: L. sakei and L. curvatus were separately incubated in vacuumed-packaged raw beef as bio-protective cultures to inhibit the naturally contaminating microbial load. Dynamic changes of the microbial diversity of inoculated or non-inoculated (control) samples were monitored at $4^{\circ}C$ for 0 to 38 days, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Results: The DGGE profiles of DNA directly extracted from non-inoculated control samples highlighted the order of appearance of spoilage bacteria during storage, showing that Enterbacteriaceae and Pseudomonas fragi emerged early, then Brochothrix thermosphacta shared the dominant position, and finally, Pseudomonas putida showed up became predominant. Compared with control, the inoculation of either L. sakei or L. curvatus significantly lowered the complexity of microbial diversity and inhibited the growth of spoilage bacteria (p<0.05). Interestingly, we also found that the dominant position of L. curvatus was replaced by indigenous L. sakei after 13 d for L. curvatus-inoculated samples. Plate counts on selective agars further showed that inoculation with L. sakei or L. curvatus obviously reduced the viable counts of Enterbacteraceae, Pseudomonas spp. and B. thermosphacta during later storage (p<0.05), with L. sakei exerting greater inhibitory effect. Inoculation with both bio-protective cultures also significantly decreased the total volatile basic nitrogen values of stored samples (p<0.05). Conclusion: Taken together, the results proved the benefits of inoculation with lactic acid bacteria especially L. sakei as a potential way to inhibit growth of spoilage-related bacteria and improve the shelf life of vacuum-packaged raw beef.

• 한국주조공학회지
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• 제25권6호
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• pp.240-248
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• 2005

The rheocasting characteristics are strongly influenced by the microstructural morphology such as particle size, form factor and contiguity. In this study, the effect of structural morphology on fluid flow characteristics of A356 semi-solid alloy was investigated with a vacuum suction fluidity test. Semi-solid metal slurry was made by the mechanical stirring, the liquidus casting, and H-NCM to be analysed. H-NCM could obtain uniform and fine globular microstructures of 0.9 form factor and 55 ${\mu}m$ particle size. Inoculation was found to be effective for reducing particle size, however, for H-NCM it should be avoided due to the cause of increasing contiguity. The fluidity test indicated that the non-stirring method had higher fluidity and smaller liquid segregation in the same solid faction of 0.4 than the stirring method, for smaller particle size and higher form factor. It was observed that liquid segregation decreased as the particle size is smaller and form factor is higher. The results of die-casting experiment were a good agreement with those of fluidity test.

• Asian-Australasian Journal of Animal Sciences
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• 제17권10호
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• pp.1390-1394
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• 2004

We have achieved efficient transformation system for forage-type tall fescue plants by Agrobacterium tumefaciens. Mature seed-derived embryogenic calli were infected and co-cultivated with each of three A. tumefaciens strains, all of which harbored a standard binary vector pIG121Hm encoding the neomycin phosphotransferase II (NPTII), hygromycin phosphotransferase (HPT) and intron-containing $\beta$-glucuronidase (intron-GUS) genes in the T-DNA region. Transformation efficiency was influenced by the A. tumefaciens strain, addition of the phenolic compound acetosyringone and duration of vacuum treatment. Of the three A. tumefaciens strains tested, EHA101/pIG121Hm was found to be most effective followed by GV3101/pIG121Hm and LBA4404/pIG121Hm for transient GUS expression after 3 days co-cultivation. Inclusion of 100 $\mu$M acetosyringone in both the inoculation and co-cultivation media lead to an improvement in transient GUS expression observed in targeted calli. Vacuum treatment during infection of calli with A. tumefaciens strains increased transformation efficiency. The highest stable transformation efficiency of transgenic plants was obtained when mature seed-derived calli infected with A. tumefaciens EHA101/pIG121Hm in the presence of 100 $\mu$M acetosyringone and vacuum treatment for 30 min. Southern blot analysis indicated integration of the transgene into the genome of tall fescue. The transformation system developed in this study would be useful for Agrobacterium-mediated genetic transformation of tall fescue plants with genes of agronomic importance.

• Journal of Microbiology and Biotechnology
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• 제4권4호
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• pp.316-321
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• 1994

We investigated the possibility of industrial application and economit process of high temperature fermentation by thermotolerant alcohol producing yeasts as previously reported. From the 20% glucose media, the RA-74-2 produced 11.8% (v/v) ethanol at $32^{\circ}C$ (0.5% inoculum) and 10.6% (v/v) ethanol at $40^{\circ}C$ (3% inoculum), respectively. Also, 11.3% (v/v) ethanol was produced for 96 hours in the temperature-gradient fermentation. These results suggest that the RA-74-2 could isuccessfully be applied to save the cooling water and energy in industrial scale without re-investment or modification of established fermentation systems. When potato starch was used as the substrate for the RA-74-2, high temperature fermentation above $40^{\circ}C$ was more appropriate for industrial utilization because organic nitrogen was not necessary to economical fermentation. As the naked barley media just prior to industrial inoculation, taken from the Poongkuk alcohol industry Co., were used, 9.6% (v/v) ethanol was produced at $40^{\circ}C$ for 48 hours in jar-fermentor scale (actually, 9.5-9.8% (v/v) ethanol was produced at 30~$32^{\circ}C$ for 100 hours in industrial scale). The ethanol productivity was increased by the high glucoamylase activity as well as the high metabolic ratio at $40^{\circ}C$ Therefore, if the thermotolerant yeast RA-74-2 would be used in industrial scale, we could obtain a high productivity and saving of the cooling water and energy. Meanwhile, the RA-912 produced 6%(v/v) ethanol in 10% glucose media at $45^{\circ}C$ and showed the less ethanol-tolerance compared with industrial strains. As the produced alcohol was recovered by the vacuum evaporator at $45^{\circ}C$ in 15% glucose media, the final fermentation ratio was enhanced (76% of theoretical yields). This suggest that a hyperproductive process could be achieved by a continuous input of the substrate and continuous recovery of the product under vacuum in high cell-density culture.

• 식물병연구
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• 제27권1호
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• pp.8-16
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• 2021

본 연구에서는 마이크로웨이브 플라즈마(microwave plasma)를 이용하여 종자에 감염된 Acidovorax citrulli 11-251의 살균효과를 확인하였다. 감압처리를 통하여 수박 종자에 A. citrulli 11-251를 인공접종하여 이병 종자를 제작하였으며, Aac ImmunoStrip및 scanning electron microscope 확인 결과, 종피 및 종자 내부에 1×107/30분 처리한 조건에서 감염되었음을 확인하였다. 플라즈마 처리는 50 W (3분, 5분, 10분), 80 W (3분, 5분, 10분), 100 W (3분, 5분, 10분) 조건으로 실험 결과, 인공감염종자를 플라즈마 처리 시 대조구와 비교해보면 종피의 경우 80W/10분, 99.56%의 살균 효과를 보였고, 종자 내부는 80 W, 100W/10분, 100%의 높은 살균 효과를 보였다. 인공접종 종자를 사용하여 플라즈마 살균장치의 종자살균 효과를 확인하였다. 하지만 발아율은 무처리구보다 플라즈마 처리 시 급격히 떨어지는 것을 확인하였다. 주사전자현미경 관찰 결과, 플라즈마 처리가 A. citrulli 11-251의 세포막을 파괴하는 것을 확인하였다. 또한, A. citrulli가 접종된 수박 종자를 이용하여 플라즈마 처리 시 살균 및 발아율을 높일 수 있는 최적 조건에 대한 추가 실험이 수행될 예정이다.