관동맥질환에서 저밀도 지단백 입자 크기의 분포

임효영,김인숙,승기배,강동헌,전두수,장기육,박준철,이수영,홍순조,최규보 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.8

김치에서 분리한 Lactobacillus sp. JC-7과 Lactobacillus acidophilus 88간의 Electrofusion 최적조건 설정

조영배,최현정,백형석,전홍기 부산대학교 유전공학연구소 1997 분자생물학 연구보 Vol.13 No.-

김치 발효 숙성기간을 연장하고 신선도를 오랫동안 유지 할 수 있는 김치발효 starter의 개발을 목적으로 최적숙성기에 있는 김치로부터 bacteriocin생성능이 없는 유산균을 분리하여 동정하였으며, bacteriocin생성능이 우수한 L.acidophilus 88을 융합시키기 위해 electrofusion에 대한 최적 조건을 검토하였다. 분리균주는 Lactobacillus속으로 동정되어 Lactobacillus sp. JC-7이라 명명하였다. Electrofusion에 의해 생성된 융합주를 식별하기 위해 streptomycin(2.5㎎/ml)에 내성을 나타내는 Lactobacillus sp. JC-7변이주와 kanamycin(600㎍/ml)에 내성을 나타내는 L.acidophilus 88변이주를 분리하였다. Electrofusion을 100V/㎝, 120msec(72ohms,1670 capacitance) 에서 수행했을 때 융합효율이 가장 양호하였으며 전기장의 세기와 시간이 중가할수록 융합 효율이 현저히 감소하였다. 2가 양이온은 농도가 중가할수록 대체적으로 융합효율을 감소시키는 경향을 나타내었으나 1mM MGCl_2에서는 대조군에 비해 융합효율이 약간 증가하였다. PEG매개에 의한 융합법의 융합효율을 비교한 결과, 융합효율은 chemical fusion<electrofusion<electrofusion+20% PEG순을 나타내었다. Evaluation of Optimum Conditions for the Electrofusion between Lactobacillus sp. JC-7 Isolated from Kimchi and Lactobacillus acidophilus 88. Young-Bae Jo, Hyun-Jung Choi, Hyung-Suk Baik and Hong-Ki Jun*. Department of Microbiology, Pusan National University, Pusan 609-735,Korea-A lactic acid bacterium was isolated from kimchi. The isolated strain was identified as the genus Lactobacillus thrugh its morphological characteristics and named as Lactobacillus sp. JC-7. The optimum conditions for the electrofusion between streptomycin(2.5㎎/ml)resistant mutant of Lactobacillus acidophilus 88 and kanamycin(600㎍/ml) resistant mutant Lactobacillus sp. JC-7 were evaluated. The highest number of fusants were obtained at a capacitance value of 120msec(1670㎌), a field strength of 100V/㎝,and a pulse controller setting of 72Ω. The potimum pH of elecroporation buffer was 7.5 and the concentration of divalent cation was 1mM MG^2+. Electrofusants were efficiently obtained by addition 20% polyethylene glycol to electroporation buffer. The yield of fusion was better than that of using polyethylene glycol mediated chemical induction.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

방선균 J-144K가 생산하는 Adenosine Deaminase Inhibitor에 관한 연구

전홍기,김상웅,조영배,이인 부산대학교 유전공학연구소 1996 분자생물학 연구보 Vol.12 No.-

Adenosine deaminase의 새로운 저해제를 검색하기 위해 토양으로부터 adenosine deaminase 저해제를 생산하는 8균주의 방선균을 분리하였으며, 그중에서 저해활성이 가장 우수한 J-144K균주를 공시균주로 선정하였다. Adenosine deaminase 저해제 생산을 위한 최적배지 조성은 1.0% dextrose, 0.5% yeast extract, 0.5% peptone, 0.1% KH_2PO_4이었으며, 초적온도와 pH는 각각 30˚C와 7.0이었다. 이러한 조건에서 500ml용 진탕플라스크에 최적배지 100ml를 넣어 배양했을 경우 정지기인 배양 60시간째에 adenosine deaminade 저해활성이 가장 높게 나타났다. 분리균주 J-144K의 배양상등액으로부터 활성탄 흡착 및 유기용매 추출, Dowex 50 H^+ X-8 column chromatography, Dowex 1 Cl^- X-8 column chromatography, Sephadex G-15 gel filtration 등의 과정을 거쳐 adenosine deaminase 저해제를 정제한 결과, 3가지 종류의 저해제가 존재함을 알 수 있었다. In the screening of actinomycetes' culture filtrate for inhibitor of adenosine deaminase, a novel inhibitor was found in a cultured broth of strain J-144K. The optimum conditions for the adenosine deaminase inhibitor production from the isolated strain J-144K were evaluated. This strain showed the maximum yield of adenosine deaminase inhibitor when grown at pH 7.0 and 30˚C for 60 hours in the medium of 1.0% dextrose, 0.5% yeast extract, 0.5% peptone and 0.1 % KH_2PO_4 under the aerobic condition. Through the activated charcoal extraction, methanol fractionation, Dowex 50 H^+X-8 ion exchange column chromatography, Dowex Cl^- X-8 ion exchange column chromatography, and Sephadex G-15 gel filtration procedures, this inhibitor was purified with three materials.

Lactobacillus casei와 Lactobacillus delbrueckii간의 Protoplast 융합에 관한 연구

전홍기,김미경,백형석 부산대학교 유전공학연구소 1992 분자생물학 연구보 Vol.8 No.-

유산균주의 균주개량방법의 일환으로 protoplast fusion 방범을 사용하여 linconmycin에 내성을 나타내는 Lactobacillus casei KCTC 1121과 rifampicin에 내성을 나타내는 Lactobacillus delbrueckii JK-414의 protoplast 형성과 재생, 융합에 대한 조건 및 융합주의 생리학적 성질 등을 검토하였다. Lactobacillus casei와 Lactobacillus delbrueckii JK-414는 삼투압 안정제로 sucrose가 함유된 protoplast forming buffer에서 5μg/ml의 mutanolysin으로 42˚C, 15분간 처리했을 때 Protoplast 형성율이 높게 나타났다. L. casei와 L. delbrueckii는 대수 증식기 중반에서 protoplast가 가장 잘 형성되었으며, MRS 배지에 삼투압 안정제로 sucrose 10%, MgCl_2 6mM, CaCl_2 6mM, gelatin 2.5%를 첨가하여 만든 재생배지에서 재생효율이 가장 좋았다. 한편, L. casei와 L. delbrueckii 사이의 protoplast 융합은 40%의 PEG 4,000을 처리하였을 때 가장 양호하였으며, 그 융합 효율은 3.2×10^-4이었다. L. casei가 L. delbrueckii보다 높은 산 생성능을 보였으며 융합주 중 특히 F23, F35의 산 생성능이 우수하였다. 융합주 중 F23, F24의 protease 활성이 모균주의 protease 활성보다 높았으며, 이들 융합주의 DNA 함량은 모균주의 2배였다. Protoplast fusion between lincomycin resistant Lactobacillus casei KCTC 1121 and rifampicin resistant Lactobacillus delbrueckii JK-414 was attempted to obtain the improved strains. Protoplasts of L. casei and L. delbrueckii were produced by mutanolysin digestion at 42˚C for 15 min. L. casei cells were converted to protoplasts by treating with 5 μg/ml of mutanolysin in 20 mM HEPES buffer (pH 7.0) containing 0.75 M sucrose at the middle logarithmic growth phase. In case of L. delbrueckii 1.0M sucrose was used osmotic stabilizer. Regeneration of protoplast in both strains was efficiently accomplished on the regeneration medium containing 10% sucrose, 6mM MgCl_2, 6mM CaCl_2, and 2.5% gelatin. Protoplast fusion between L. casei and L. delbrueckii was carried out in the presence of 40% of PEG 4,000. The frequency of protoplast fusion was found to be about 3.2 × 10^_4. Acid production of L. casei was better than that of L. delbrueckii. Among fusants, F23 and F35 exhibited excellent lactic acid production. F23 and F24 exhibited the improved proteolysis compared to that of the parent strains and they had twice as much as DNA content of the parents.

김치 분리균인 Bacillus sp. JK-43이 생산하는 Cyclodextrin Glucanotransferase의 생산 및 특성

전홍기,배경미,김영희,백형석 부산대학교 유전공학연구소 2000 분자생물학 연구보 Vol.16 No.-

김치 시료로부터 자동산화되지 않으며 열 및 중성 pH에서 안정한 AA 유도체인 AA-2G를 생산할 수 있는 당전이활성을 가진 CGTase 생산균주를 분리하였고, 분리균주의 형태학적, 배양학적, 생리학적 성질 및 16s-rDNA sequences를 조사한 결과 그람 양성의 간균으로 호기성이며 내생포자를 형성하는 전형적인 중온성 Bacillus sp. JK-43으로 동정되었다. Bacillus sp. JK-43의 CGTase는 AA-2G 뿐만 아니라 AA-6G로 추정되는 물질을 함께 생산하였으며, 효소 최적생산조건은 1.0% soluble starch, 1.0% yeast extract, 1.0% Na_2CO_3, 0.1% K_2HPO_4 그리고 0.02% MgSO_4·7H_2O가 함유된 배지에서 pH 7.0, 37℃에서 26시간 동안 진탕배양하였을 때였다. 각종 당공여체에 따른 Bacillus sp. JK-43의 AA-2G 생산성을 조사한 결과 β-CD에서 가장 높은 AA-2G 생산성을 보였으며, 식혜제조폐액인 엿기름 및 밥당화액에서도 비교적 높은 AA-2G 생산성을 보였다. 또한 여러 가지 당수용체에 대한 JK-43의 CGTase의 당전이 반응을 검토한 결과 sucrose, mannitol 및 inositol에서 높은 당전이 수율인 70∼90%를 나타내었다. A bacterial strain, designated as JK-43, producing extracellular cyclodextrin hlucanotransferase (CGTase)[EC 2.4.1.19] was isolated from kimchi. The CGTase from isolated strain JK-43 showed the transglucosylation activity from soluble starch to L-ascorbic acid (AA) compared to those obtained from other strains. A main product formed by this reaction was identified as 2-O-α-glucopyranosyl L-ascorbic acid (AA-2G) by testing its susceptibility to α-glucosidase hydrolysis, the HPLC prodiles, and through the elementary analysis. The β-CD, γ-CD, potato starch and corn starch were identified to be suitable glucosyl donor for transglucosylation reaction on AA by CGTase. Acceptor specificity on AA-2G production was examined by use of AA, Iso-AA and AA-2P. Transglucosylation was observed toward AA-2P as well as AA. The microorganism isolated from kimchi was identified as a strain of Bacillus sp. JK-43 based on the maximal CGTase production was observed in a medium containing 1.0% soluble starch, 1.0% yeast extract, 1.0% Na_2CO_3, 0.1% K_2HPO_4, and 0.02% MgSO_4·7H_2O with initial pH 7.0. The strain was cultured at 37℃ for 26 hrs with reciprocal shaking.

운동선수의 임장불안에 대한 연구

홍관이,이광재,김두경,부기원,노성규,한상준,박기동,오수일,문병용,이철규,박장평,엄기진,박남환 江原大學校附設 體育科學硏究所 1984 江原大學校附設體育科學硏究所論文集 Vol.- No.9

This study is designed to grasp the elements and situations of stage fright in order to propose a part of ways to cope with it. We make 511 top-class high school players, male and female, in the central districts (Seoul, Inchon, Kyungki, Chungbuk, and Kangweon Province) on object of questionnaire, and get the following results. Through players generally have all-round characters they show weakness in the superiority and emotional stability while showing strength in the sonformity. This fact comes to be related to the elements which cause stage fright. Physiological changes also have many effects on the symptom of stage fright. Especially, stage fright increases when players show sensitive reaction to the self-consciousness of final consequence which comes from the tension or uneasiness of sympathetic nerve, Thus, it turns out that players make use of reducing psychological burden by physical exercise or adjusting the level of demanded result in order to release the stage fright.

외경 0.25 ㎜ 동맥의 단단 및 단측문합법

전대우,정재홍,강진성,한기환 大韓成形外科學會 1989 Archives of Plastic Surgery Vol.16 No.3

Microvascular surgery has rapidly developed in the last 30 years and vessels of 1.0 mm can be anastomosed easily with a patency rate over 90 percent and is widely used in clinical practice with remarkable success. To obtain more successful microvascular anastomosis in smaller vessels, the improvement in methods of microanastomosis, the development of microvascular instruments including the operating microscope along with microsutures, and anticoagulants are needed. These improvements made microvascular anastomoses of vessels that are less than 0.5mm in extemal diameter possible. Huang et al.? performed anastomoses of the vessels in rats with an external diameter of 0.2 mm using a high magnification operating microscope, specially designed microinstruments, and fine sutures, and achieved a patency rate of 76 percent in the second postoperative week. However, we tried to anastomose vessels with an external diameter of 0.25 mm with ordinary instruments and 11-0 nylon. Animal studies on 180 rats were carried out by doing end-to-end anastomoses and 180 end-to-side anastomoses. In the end-to-end and end-to-side anastomoses, each 180 rats were then divided into 3 groups each. Group A was the control group. Aspirin and persantin were given orally in group B. Ticlopidine hydrochloride was given orally in group C. The method of end-to=end anastomosis was as follows : A superficial epigastric artery as small as 0.25 mm in diameter was severed transversely and longitudinal incisions, the length of the arterial diameter, were made down opposite sides of each end. Each flared fragment of the proximal end is approximated with each distal end and sutured together by only two stitches. The method of end-to-side anastomosis was as follows. In the side of the femoral artery an elliptical hole was made the same length of the circumference of the superficial epigastric artery, then the superficial epigastric artery was incised in the same manner as the end-to-end anastomosis. The flared ends of the superficial epigastric artery were then inserted into the hole of the femoral artery and sutured by four stitches. Light microscopic and scanning electron microscopic observation was performed serially at 3 days, 2 weeks, 3 weeks after the microvascular anastomosis for studying change of vessel diameter and histopathological changes at the microvascular anastomotic sites. The results were as follows : 1. The patency rate for the end-to-end anastomoses in the third postoperative week was 25% in the control group(A), 35% in the aspirin-persantin group(B), and 40% in the ticlopidine group(C) ; in the end-to-side anastomoses, 45% in group A, 50% in group B, and 60% in group C. 2. In the patency rate, the ticlopidine group is slightly higher than the aspirin-persantin group and even higher than the control group (P<0.05) in the end-to-end and end-to-side anastomoses. However, the end-to side group is higher in all 3 groups than the end-to-end one (P<0.1). 3. The intimal regeneration in all arteries was completed at end of the third postoperative week in the end-to-end and end-to-side anastomoses. 4. Changes of the internal diameter in anastomosed vessels showed luminal narrowing in the vessels at the third postoperative day and still narrowing at the second and third postoperative week in the end-to-end anastomoses. However, initial postoperative widening continued into the third postoperative week in the end-to-side anastomoses. The authors got a high success rate of anastomoses of very small arteries approximately 0.25 mm in external diameter, by developing a method of using an ordinary microscope and instruments, 11-0 nylon suture, and the administration of ticlopidine hydrochloride which is a more powerful anticoagulant than aspirin-persatin.

스쿠버 다이빙시 안전수역과 해양수역의 변화에 따른 혈중 젖산농도 및 CPK량의 변화 비교

홍성준,이상학,김민환,김기운 한국스포츠리서치 2003 한국 스포츠 리서치 Vol.20 No.1

For the comparative analysis of the blood lactate concentration of scuba diver according to change from safety zone to sea and of the change of amount of CPK while scuba diving, C university measured the blood lactate concentration and amount of CPK against middle level and debutant scuba divers. As a result, the following differences ranging from 1) to 4) were found in divers by each factor. 1) The blood lactate concentration and CPK amount of clivers out of safety zone were 2.68 and 225.70 respectively. They were out of sea area 3.70 and 337.90 respectively. The change in blood lactate concentration out of safety zone was higher than out of sea area and CPK amount was found higher from safety zone than from sea area. But to find what differences between the blood lactate concentration and CPK amount between safety zone and sea area, I implemented independent T-test against average differences, the significance of blood lactate was .092 while that of CPK amount was .312. Therefore, the blood lactate concentration and CPK amount were not significant in safety zone and sea area. In other words, there is no significant differences in change of blood lactate concentration and CPK amount of clivers in change from safety zone to sea area. 2) The average blood lactate concentration and CPK amount in 30 minutes after going out of safety zone were 2.04 and 259,80 respectively and the average blood lactate concentration and CPK amount in 30 minutes after going out of sea area zone were 2.28 and 377.60 respectively. The blood lactate concentration and CPK amount during 30-min rest after going out of safety zone were found higher in sea area. But to find what differences between the blood lactate concentration and CPK amount between safety zone and sea area in 30 minutes out of waters, I implemented independent T-test against average differences, the significance of blood lactate was .592 while that of CPK amount was .307. Therefore, the blood lactate concentration and CPK amount after 30 minutes were not significant in safety zone and sea area. In other words, there is no significant differences in change of blood lactate concentration and CPK amount of divers in change from safety zone to sea area. 3) During stabilization of divers, the average blood lactate concentration and CPK amount were 2.66 and 290.80 respectively, the average blood lactate concentration and CPK amount after going out of safety zone were 2.68 and 257.70 respectively and the average blood lactate concentration and CPK amount during 30 minutes after going out of safety zone were 2.04 and 259.80 respectively and the average blood lactate concentration and CPK amount after going out of sea area were 3.70 and 377.90 respectively and the average blood lactate concentration and CPK amount during 30 minutes after going out of sea area were 2.28 and 377.60 respectively. From the above results of higher concentration and CPK of divers going out of sea area, the sea environment gives more impact on divers. 4) The conclusion of each factor and rest is as follows: The significance of blood lactate concentration and CPK amount during stabilization and out of safety zone were .961 and .666 respectively. Therefore, there is no significance in divers resting and going out of safety zone. The significance of blood lactate concentration and CPK amount during 30 minutes of rest and out of safety zone were .083 and .683 respectively. Therefore, there is no significance during 30 minutes of divers resting and going out of safety zone. The significance of blood lactate concentration and CPK amount during stabilization and out of sea area were .035 and .514 respectively. Therefore, there is no significance in clivers resting and going out of sea area. The significance of blood lactate concentration and CPK amount during 30 minutes of rest and out of sea area were .292 and .507 respectively. Therefore, there is no significance during 30 minutes of clivers resting and going out of sea area.

Lactobacillus casei와 Lactobacillus delbrueckii간의 Protoplast 융합에 관한 연구

전홍기,김미경,백형석 한국산업미생물학회 1992 한국미생물·생명공학회지 Vol.20 No.1

유산균주의 균주개량방법의 일환으로 protoplast fusion 방법을 사용하여 lincomycin에 내성을 나타내는 Lactobacillus casei KCTC 1121과 rifampicin에 내성을 나타내는 Lactobacillus delbrueckii JK-414의 protoplast 형성과 재생, 융합에 대한 조건 및 융합주의 생리학적 성질 등을 검토하였다. Lactobacillus casei와 Lactobacillus delbrueckii JK-414는 삼투압 안정제로 sucrose가 함유된 protoplast forming buffer에서 5㎍/㎖의 mutanolysin으로 42℃, 15분간 처리했을 때 protoplast 형성율이 높게 나타났다. L. casei와 L. delbrueckii는 대수 증식기 중반에서 protoplast가 가장 잘 형성되었으며, MRS 배지에 삼투압 안정제로 sucrose 10%, MgCl_2 6 mM, CaCl_2 6 mM, gelatin 2.5%를 첨가하여 만든 재생배지에서 재생효율이 가장 좋았다. 한편, L. casei와 L. delbrueckii 사이의 protoplast 융합은 40%의 PEG 4,000을 처리하였을 때 가장 양호하였으며, 그 융합 효율은 3.2×10^-4이었다. L. casei가 L. delbrueckii보다 높은 산 생성능을 보였으며 융합주 중 특히 F23, F35의 산 생성능이 우수하였다. 융합주 중 F23, F24의 protease 활성이 모균주의 protense 활성보다 높았으며, 이들 융합주의 DNA 함량은 모균주의 2배였다. Protoplast fusion between lincomycin resistant Lactobacillus cαsei KCTC 1121 and rifampicin resistant Lactobacillus delbrueckii JK-414 was attempted to obtain the improved strains. Protoplasts of L. casei and L. delbrueckii were produced by mutanolysin digestion at 42℃ for 15 min. L. casei cells were converted to protoplasts by treating with 5㎍/㎖ of mutanolysin in 20 mM HEPES buffer (pH 7.0) containing 0.75 M sucrose at the middle logarithmic growth phase. In case of L. delbrueckii 1.0 M sucrose was used osmotic stabilizer. Regeneration of protoplast in both strains was efficiently accomplished on the regeneration medium containing 10% sucrose, 6 mM MgCl_2, 6 mM CaCl_2, and 2.5% gelatin. Protoplast fusion between L. casei and L. delbrueckii was carried out in the presence of 40% of PEG 4,000. The frequency of protoplast fusion was found to be about 3.2×10_-4. Acid production of L. casei was better than that of L. delbrueckii. Among fusants, F23 and F35 exhibited excellent lactic acid production. F23 and F24 exhibited the improved proteolysis compared to that of the parent strains and they had twice as much as DNA content of the parents.