• 미생물학회지
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• 제17권3호
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• pp.137-151
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• 1979

Germinating conidia of Aspergillus nidulans diploid heterozygous for color and other genetic markers were used to direct and distinguish genetic events such as mutation, mitotic crossingover and nondisjunction in a single test after treatment with N-methyl-N'-nitro-N-nitrosoguanidine (NG), mitomycin C(MC), and chloral hydrate(CH). The following results were obtained : 1. NG reduced the survival of conidia and increased the frequencies of miototic segregants about sevenfoli over the control ; among the mitotic segregants the predominant genetic event was mitotic crossingover. NG also produced many abnormal colonies, which appeared to be of the types caused by induced semidominant lethals or chromosomal aberrations, and the aneuploid types found spontaneously. 2. After treatment with MC the survival of conidia was reduced but few abnormal colonies were produced. The frequencies of miotic segregants were increased about threefold over the control ; in the mitotic segeregants the induced genetic event was mitotic crossingover. 3. CH gave no apparent effect on the survival of conidia and the frequencies of mitotic segregants. However, CH generated abnormal colonies, very greatly, which turned out to be of the aneuploid types. This result suggests that CH interferes with the normal distribution of chromosomes in mitosis.

• 미생물학회지
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• 제20권1호
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• pp.11-20
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• 1982

A study was undertaken to examine the effect of curing agents on the stability, curing and segregation of R plasmid pSL100. And also the stability, transfer frequency, and recombination of its segregants obtained from curing agent treatment were studied. Ethidium bromide, acridine orange, and mitomycin-C were used as curing agent. The results obtained were as follows ; 1. The curing agent ethidium bromide, acridine orange, and mitomycin-C were not effective for curing the multiple antibiotic resistant determinant of pSL100 in Salmonella typhimurium and Escherichia coli. However, they induced plasmid segregation with high frequency in S.typhimuruim LT-2strains. TcApSmCm, TcSmCmKm, TcApCm, TcAp, TcKm, Tc segregants were obtained. 2. The resistant markers of the segregents were transferred to S.typhimurium LT-2 strains with high frequencies whereas they were transferred to E.coli K-12 only with low frequencies. 3. The transconjugants obtained from conjugation between two different S.typhimurium segregants were similar to the phenotype of the original R factor pSL100 and the resistant markers were transferred to the S.typhimurium LT-2 or E.coli strain with equal frequencies, indicating that they are recombinants. 4. The transconjugants obtained from conjugation between pSL100 segrgants and pKM101, or pBR322 possessed the resistant markers of the two parental plasmids and they were transferred to both S.typhimurium and E.coli K-12 strains with the same frequencies and maintained stably, suggesting that they are also recombinants. 5. The recombinant pSL100 could be also obtained in rec A-strains of E.coli, suggesting that the gene function of rec A is required for the recombination of pSL100 segregants in E.coli.

• 한국균학회지
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• 제16권1호
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• pp.16-20
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• 1988

영지(靈芝)의 항암물질개량(抗癌物質改良)과 신품종(新品種)의 육성(育成)을 위(爲)한 (육종역법)育種方法으로 제시된 원형질체융합(原形質體融合)의 기초자료를 얻고자 영양요구성균주(營養要求性菌株)의 선발(選拔), 종간원형질체융합(種間原形質體融合)과 융합균주(融合菌株)의 선발(選拔)을 실험(實驗)하였다. 1. 돌연변이(突然變異) 대상체(對相體)로는 균사체(菌絲體), mutagen으로는 자외선(紫外線)을 사용하였는데 영양요구성균주(營養要求性菌株)의 유기율(誘起率)은5.78%이었다. 2. 영지(靈芝)와 잔나비걸상버섯간(間) 원형질체융합률(原形質體融合率)은 2.03%이었다. 3. 융합균주(融合菌株)는 환원균총(還元菌叢)의 생장속도(生長速度)와 형태(形態)를 비교(比較)하여 선발(選拔)하였고, 계대배양후(繼代培養後)의 형태(形態)와 esterase isozyme pattern의 분석(分析)에 의해서 확인(確認)하였으며, 참나무톱밥배지(培地)에서 재배(栽培)하여 자실체(子實體)를 관제(觀祭)하였다.

• 한국균학회지
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• 제16권4호
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• pp.210-213
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• 1988

맛느타리버섯(P. sapidus)의 균사체로부터 핵을 직접 분리하여 느타리버섯(P. ostreatus)의 원형질체에 전이시켜 다음과 같은 결과를 얻었다. 맛느타리버섯의 핵을 느타리버섯의 Arginine 영양요구성 균주 원형질체에 전이하여 얻은 균주의 균총 형태는 3종류로 구분되었으며, 형태 1은 균총이 두모균주의 모양으로 명확히 분리되었고, 형태 2는 균총은 분리되나 모균주와 다른 형태, 형태 3은 균총의 분리현상이 없이 안정하고 균일하게 생장하였다. 등전점 전기영동으로 핵 전이균주와 모균주의 Esterase, Malate dehydrogenase, Superoxide dismutase의 동질효소 pattern을 비교한 결과 핵 전이균주들은 모균주와 차이가 있었으며, 특히 형태 3의 두 균주는 모균주에서 볼 수 없는 새로운 band가 발견되었다.

• 한국분말재료학회지
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• 제1권1호
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• pp.79-84
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• 1994

The mechanism of activated sintering of tungsten powder was discussed in terms of diffusion and segregation of activator atoms at W grain boundaries. Shrinkage behaviours of W-0.2wt.% Ni, W-0.2wt.% Cu or pure W powder compacts during sintering at low temperatures of 900~ $1200^{\circ}C$ were investigated. It was found that the Cu additive inhibits sintering process causing lower densification than pure W compact while remarkable shrinkage occurred in the Ni added W powder. Such contrary effect was explained by comparing self diffusion processes along Ni or Cu segregated W boundaries in which Ni segregants enhance but Cu atoms retard the migration of W atoms at W boundaries.

• 대한미생물학회지
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• 제21권4호
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• pp.461-471
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• 1986

1973년부터 1985년 사이에 대구지방에서 분리된 Shigella는 약 1,200주였는데, 대부분이 Shigella flexneri였고, S. sonnei는 약 20%였으며, S. dysenteriae와 S. boydii는 극히 적었다. 분리균의 95%이상이 chloramphenicol(Cm), tetracycline(Tc), streptomycin(Sm), sulfisomidine(Su), ampicillin(Ap), trimethoprim(Tf) 등의 전부 또는 일부 약제에 내성이었으며, kanamycin, nalidixic acid(Na)와 rifampin(Rf)에 내성인 균주는 소수 있었으나, cephaloridine, gentamicin, amikacin 등에 내성인 균주는 없었다. 1973년에 분리된 균은 약 절반이 약제내성이었으나, 1977년 이후 분리된 균은 95% 이상이 약제내성이었다. 1977년 까지는 Cm, Tc, Sm 및 Su의 4제 내성균이 가장 많았으나 1978년 부터는 Cm, Tc, Sm, Su, Ap 및 Tp의 6제 내성균이 가장 많았다. 약 75%의 균이 그 약제내성을 접합에 의하여 Escherichia coli에 전달하였으므로 이 약제내성은 R plasmid에 의한 것으로 생각되었다. 대다수의 균에 있어서 약제내성 전부를 E. coli에 전달하였으나, Na와 Rf의 내성은 전달되지 않았다. 일부 균주의 약제내성은 E. coli에 전달될 때 분리되는 일이 있었으나, 그 수는 극히 적었다. Shigella의 R Plasmid는 대부분이 비적합성군(incompatibility group) F II에 분류되었으나, 극소수는 B군에 속하였고 군별이 안되는 것도 있었다.

• Journal of Microbiology and Biotechnology
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• 제6권4호
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• pp.286-291
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• 1996

A study was conducted to investigate the characteristics of segregation and alcohol fermentation of intergeneric fusants. The protoplast fusion of both Pichia stipitis CBS 5776 and Saccharomycess cerevisiae STV 89 was carried out. The fusion frequency was $5\times10^{-8}$ and among fusants selected, a fusant F5 showed the best results in ethanol production by sucrose and xylose fermentations. The performance of xylose fermentation by this fusant was better than that of P. stipitis CBS 5776 and fusant F5 exhibited sucrose fermentation patterns intermediate to the two parent strains. The fusant F5 was segregated into a pair of parental strains during the several culture passages. In the average, 91$%$ of colonies had a similar characteristics of P. stipitis while 7$%$ of colonies resembled S. cerevisiae. Only 2$%$ of colonies had the characteristics of the original fusants. At the sixth passage, all segregants resembled P. stipitis. From these results it is suggested that intergeneric protoplast fusion led to an integration of S. cerevisiae genes, rather than whole chromosomes, within the entire genome of P. stipitis.

• Journal of Plant Biotechnology
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• 제31권4호
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• pp.261-266
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• 2004

Agrobacterium을 이용하여 도입된 유전자의 세대진전, 교잡 등에 따른 유전적 안정성을 확인코자, 형질 전환으로부터 얻어진 bar 유전자가 도입된 형질전환 식물체들을 상호 교배, 여교배, T$_4$ 세대까지의 자식의 반복 등에 의해 유전적 안정성을 검토하였다. 조합이나 계통에 따라서는 일부 멘델식 분리를 따르지 않고 제초제 Basta에 대한 저항성이 사라지거나 저항성개체보다 감수성개체가 기대치보다 많은 등의 경우가 있었으나, 대부분 멘델식 분리를 따르고 있어 세대진전, 교배 등에 의해서도 유전적 안정성이 높게 유지됨을 확인할 수 있었다.

• 한국균학회지
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• 제21권4호
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• pp.323-331
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• 1993

The protoplast formation and intergeneric protoplast fusion between Gliocladium virens and Trichoderma harzianum were attempted to obtain fusants. Protoplast formation was the most effective when the strains were treated with concentration of 5 mg/ml of Novozyme 234 and Cellulase at $25^{\circ}C$ for 3 hours in phosphate buffer, pH 6.5, supplemented with 0.6 M sorbitol as osmotic stabilizer. Auxotrophic mutants of G. virens G88 did not grow in minimal medium and benomyl resistant T. harzianum T95 from wild types, however, was selected by treatment with UV light as genetic marker to isolate fusants. When the intergeneric protoplast fusion between G. virens G88 and T. harzianum T95 was carried out using 30% PEG 4000 containing 10 mM $CaCl_{2}$, and 50 mM glycine (pH 8.5) as fusogenic agent at $25^{\circ}C$ for 10-15 min, the fusion frequency was $0.8{\times}10^{-4}$. Fusants obtained from intergeneric protoplast fusion were spontaneously segregated into va rious strains by continous culture on complete medium. Several intergeneric hybrids were classified into three types: parent-like hybrids, segregants, and recombinants.

• 한국작물학회지
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• 제44권3호
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• pp.277-281
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• 1999

Dull grains segregated from F$_3$ and F$_4$ of the crosses between two dull mutants and a glutinous cultivar were compared with non-glutinous and glutinous segregants for their physicochemical properties. Amylose content of dull rice grain segregated from the dull/glutinous cross showed the intermediate value between glutinous and non-glutinous rice grain, whether it is controlled by the recessive or dominant gene. Alkali digestibility value (ADV) of dull rice grain was lower than that of glutinous or non-glutinous rice. A positive correlation was found between ADV and amylose content of homozygous non-glutinous or dull F$_4$ grains, but a negative relationship was observed in glutinous grains. Protein content of dull grain was significantly higher than that of glutinous or non-glutinous grain segregated from the same cross, while those of glutinous and non-glutinous grains were not different. Among gelatinization characteristics, initial pasting temperature and peak viscosity of dull grains were higher than glutinous rice, and were not different with non-glutinous grain. Hot, cool and consistency viscosities of dull grain were intermediate between glutinous and non-glutinous rices. Dull grains showed the highest breakdown viscosity and the lowest setback viscosity among the three endosperm types.