• Journal of Microbiology and Biotechnology
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• 제13권4호
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• pp.560-563
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• 2003

During our previous studies on the relationship between nutrient requirements of S. hygroscopicus C9 and rapamycin biosynthesis, we developed chemically-defined media containing among other nutrients, aspartic acid, arginine, histidine, or ammonium sulfate. However, these media (“Cheng et al. medium” and “Lee et al. medium”) showed very slow growth characterized by a very long lag phase of growth. In an attempt to develop a chemically-defined or semi-defined medium to support more rapid growth and increased cell production, we have carried out studies to shorten the lag phase. Of the various additives tested, vitamin-free casein acid hydrolysate was the most significant by shortening the lag phase by 2-3 days. Mixtures of amino acids failed to replace casein acid hydrolysate. The active principle passed through an ultrafilter with a molecular weight cutoff of 1,000 and thus may be a peptide. The present work has yielded a semi-defined medium which should be useful for further growth studies on S. hygroscopicus C9.

• KSBB Journal
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• 제10권2호
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• pp.137-142
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• 1995

Sucrose를 탄소원으로 이용할 수 있는 대장균 W 를 A. eutrophus PHA 합성 유전자가 cloning된 높 은 복제수의 plasmid pSYL105로 형질전환하여 단 순배지에서 배양시 $0.21g/\ell$ 의 낮은 PHB 농도를 얻었다. 이에 107}지의 복합질소원을 소량 첨가하여 PHB 합성에 미치는 영향을 살펴 보았다. Tryptone, casamino acids, casein hydrolysate, 혹은 soy bean hydrolysate의 첨가시 PHB 합성 이 10배 이 상 증대되었다. 또한 이때 sucrose로부터의 PHB 수율도 10배 이상 증가하여 이 네 가지 복합질소원 을 척정 농도로 첨가함으로써 sucrose로부터 효과적인 PHB 생산이 가능함을 알았다.

• 대한약리학회지
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• 제12권1호
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• pp.57-62
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• 1976

Using modified technique of Schmidt et al, as described previously (Korean J. Pharmacol 9 : 17, 1973), the stomach of female rats were perfused with physiological saline under urethane anesthesia. The acid-secretory response of the perfused stomach to i.v. hypertonic glucose (50%), casein hydrolysate (20%) or saline (6%) solution were studied with or without histamine or methacholine stimulation. A significant decrease of acid secretion from the rat stomach was induced by i.v. hypertonic glucose or saline solution. The histamine-stimulated acid secretion was also decreased by simultaneous administration of the hypertonic glucose or saline. However, methacholine-stimulated acid response was not affected by the hypertonic glucose. Intravenous infusion of 20% casein hydrolysate solution resulted in an increase in acid output from the stomach under histamine stimuli. These results lead to the conclusion that the inhibitory responses of acid secretion due to i.v. hypertonic glucose solution are brought through the effect of histaminergic, not cholnergic mechanism(s) in the gastric secretion.

• 한국식품영양과학회지
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• 제31권2호
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• pp.263-270
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• 2002

본 연구에서는 casein 펩타이드 분획물이 정상 및 고지방식을 섭취한 흰쥐에서의 혈청 및 조직의 지질 농도에 미치는 섭취효과를 검토하고자 하였다. 정상 지방식이 (7% soybean oil & cholesterol-free; Expt I)를 섭취한 흰쥐는 정상 혈청 지질농도를 나타내는 것으로, 분배설량이 약간 증가하는 경향을 나타내긴 하였지만 이때 casein 펩타이드 분획물군의 혈청,간조직의 지질농도에 대한 효과는 유의적인 차이가 없었다. 하지만, 순환기계질환의 주요 인자인 HDL/LDL비는 친.소수성 펩타이드에서 유의적으로 높은 경향을 나타내었다. 고지방 콜레스테롤식이 (18% beef tallow & 1% cholesterol; Expt II)를 급여하였을 경우, 친.소수성 펩타이드 분획물군에서 분중으로의 총지질, 총콜레스테롤 및 중성지방의 배설량이 유의 적 (p<0.05)으로 또는 증가하는 경향을 나타내었다. 이런 결과, 고지방식이를 급여했을 때 친.소수성펩타이드 분획물군이 casein군에 비해 혈중 및 간조직 중의 지질 농도가 낮아지는 경향을 나타냈다. 또한 HDL/LDL비도 casein군에 비해 친.소수성 펩타이드 분획물군에서 높게 관찰되는 것으로, 이는 고 혈증 위험요소를 저하시키는 효과가 있는 것으로 사료되었다. 친.소수성 펩타이드 분획물(CL & CB)의 아미노산 조성 결과, 친.소수성 펩타이드 식이의 glycine과 methionine함량은 casein 식이의 조성과 거의 비슷한데, arginine과 lysine함량은 casein 식이의 조성과 상당히 달랐다. 또한 혈중 지질농도를 낮추는 것으로 보고되어지는 arginine/lysine 비와 glycine/methionine 비는 친.소수성 펩타이드 분획물 식이(CL & CB)에서 낮게 관찰되었다. 이러한 결과는 동물실험 결과와 같이 고찰해볼 때, 아미노산 조성이 혈중 및 조직 중의 지질저하 효과에 미치는 영향이 그다지 크지 않은 것으로 사료되었고, 앞으로 이에 대한 연구가 더욱 필요하였다. 친.소수성 casein 펩타이드 분획물의 지질 대사에 미치는 영향을 관찰하여 보았을 때, 고지혈증 및 고콜레스테롤혈증 흰쥐에서 혈중 및 간조직의 지질함량을 저하 시키는 효과가 있는 것으로 나타났다. 이에 가능한 기전으로는 분중으로의 지질 배설량을 증가시킨 것에 기인한 것으로 해석되었으며, 섭취기간이 길어질수록 효과가 확실해질 것으로 기대되었다. 또한 casein 펩타이드 분획물의 아미노산 조성비의 차이라기보다는 펩타이드 자체의 효과임이 시사되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권1호
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• pp.61-65
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• 2005

The objective of this work was to investigate the nutritional requirements for the growth of Actinomyces sp. 9RCC5 isolated from the rumen of a native goat in Korea. The growth of strain 9RCC5 on the basal medium or the medium minus certain ingredients from the basal medium demonstrated that strain 9RCC5 showed absolute requirement of vitamin B complex mixture, while hemin and volatile fatty acids (VFA) were stimulatory to growth to some extent. The 9RCC5 strain grew well with casein hydrolysate as the sole added nitrogen source. However, neither a complex of 18 amino acids nor ammonium sulfate effectively replaced casein hydrolysate. Vitamins such as riboflavin and pantothenate were essential for growth, while thiamin and biotin were stimulatory. With regard to VFA, the growth was stimulated by acetic acid but inhibited by valeric acid. Relatively large quantities of $Na^+$, $K^+$ and $Ca^{2+}$ were absolutely required for growth. Supplementation of clarified rumen fluid to the basal medium in a range of 0-10% (vol/vol) resulted in an increased rate of growth as well as an increased extent of growth.

• 한국식품영양과학회지
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• 제22권2호
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• pp.226-233
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• 1993

효소에 의한 가수분해로 식품단백질로부터 생리활성 peptide의 생성을 밝히기 위한 연구의 일환으로 효소에 의한 단백질 가수분해물의 ACE 저해작용을 검토한 결과는 다음과 같다. 1. 가수분해에 따른 ACE 저해능은 가수분해 8시간까지는 급격히 증가하다가 그 후로는 완만하게 증가하였으며, 특히 복합효소, bromelain 및 pepsin등에 의해 우수하게 나타났다. 그러나 trypsin 및 $\alpha$-chymotrypsin에 의한 egg albumin 및 casein 가수분해시에는 가수분해 8시간 이후에는 오히려 감소하는 경향을 나타내었다. 2. 단백질 가수분해물의 ACE 저해능은 첨가량의 증가와 함께 우수한 것으로 나타났으며, 가열에 대하여 비교적 안정한 것으로 나타났다. 3. 단백질 가수분해물의 아미노산 조성은 거의 유사한 것으로 나타났으며, 특히 glutamic acid의 함량이 월등히 많은 것으로 나타났다. 그러나 egg albumin 가수분해물의 경우는 glutamic acid의 함량이 적은 반면 alanine 및 cysteine의 함량이 다소 많은 것으로 나타났다 4. Gel 여과에 의한 단백질 가수분해물의 획분별 ACE 저해작용은 서로 비슷한 획 분에서 나타났으며 이 때의 분자량은 1,400부근으로 나타났다. 5. Gel 여과에 의한 ACE 저해작용 획분의 아미노산 조성은 서로 다른 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.273-278
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• 2002

Two-step fed-batch fermentations were carried out to overproduce Bacillus licheniformis maltogenic amylase (BLMA) in recombinant Escherichia coli. The first step was to increase the cell mass by controlling the feeding of a glucose solution, while the second step was designed to improve the amylase expression efficiency by supplementing organic nitrogen sources. The linear gradient feeding method was successfully adopted to maintain the glucose concentration below 0.2 g/l during the fed-batch mode, as effectively minimizing acetic acid formation. When the dissolved oxygen (DO) level became limiting, an accumulation of acetic acid and drastic decrease in specific BLMA productivity were observed. Glucose and organic nitrogen sources consisting of yeast extract and casein hydrolysate were simultaneously supplied in the pH-stat mode to further increase the specific BLMA expression efficiency. An organic nitrogen source consisting of 200 g/1 yeast extract and 100 g/1 casein hydrolysate was found to be the best among the various combinations tested. The feeding of an organic nitrogen source in the second-step fed-batch period was highly beneficial in enhancing the BLMA production. The optimized two-step fed-batch culture resulted in 78 g/l maximum dry cell mass and 443 U/ml maximum BLMA activity, corresponding to 1.5-fold increase in the dry cell mass and 3.7-fold enhancement in BLMA production, compared with the simple fed-batch fermentation.

• Nutrition Research and Practice
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• 제18권1호
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• pp.46-61
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• 2024

BACKGROUND/OBJECTIVES: An increasing life expectancy in society has burdened healthcare systems substantially because of the rising prevalence of age-related metabolic diseases. This study compared the effects of animal protein hydrolysate (APH) and casein on metabolic diseases using aged mice. MATERIALS/METHODS: Eight-week-old and 50-week-old C57BL/6J mice were used as the non-aged (YC group) and aged controls (NC group), respectively. The aged mice were divided randomly into 3 groups (NC, low-APH [LP], and high-APH [HP] and fed each experimental diet for 12 weeks. In the LP and HP groups, casein in the AIN-93G diet was substituted with 16 kcal% and 24 kcal% APH, respectively. The mice were sacrificed when they were 63-week-old, and plasma and hepatic lipid, white adipose tissue weight, hepatic glucose, lipid, and antioxidant enzyme activities, immunohistochemistry staining, and mRNA expression related to the glucose metabolism on liver and muscle were analyzed. RESULTS: Supplementation of APH in aging mice resulted in a significant decrease in visceral fat (epididymal, perirenal, retroperitoneal, and mesenteric fat) compared to the negative control (NC) group. The intraperitoneal glucose tolerance test and area under the curve analysis revealed insulin resistance in the NC group, which was alleviated by APH supplementation. APH supplementation reduced hepatic gluconeogenesis and increased glucose utilization in the liver and muscle. Furthermore, APH supplementation improved hepatic steatosis by reducing the hepatic fatty acid and phosphatidate phosphatase activity while increasing the hepatic carnitine palmitoyltransferase activity. Furthermore, in the APH supplementation groups, the red blood cell (RBC) thiobarbituric acid reactive substances and hepatic H₂O₂ levels decreased, and the RBC glutathione, hepatic catalase, and glutathione peroxidase activities increased. CONCLUSIONS: APH supplementation reduced visceral fat accumulation and alleviated obesity-related metabolic diseases, including insulin resistance and hepatic steatosis, in aged mice. Therefore, high-quality animal protein APH that reduces the molecular weight and enhances the protein digestibility-corrected amino acid score has potential as a dietary supplement for healthy aging.

• Nutrition Research and Practice
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• 제3권3호
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• pp.200-207
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• 2009

This study examined the effects of com gluten (CG) and its hydrolysate consumptions on weight reduction in rats fed a high-fat diet. Eight-month-old male Sprague-Dawley rats (n=40) were fed a high-fat diet (40% calorie as fat) for 4 weeks. They were then randomly divided into four groups and fed the isocaloric diets with different protein sources for 8 weeks. The protein sources were casein (control group), intact CG (CG group), CG hydrolysate A (CGHA group, 30% of protein as peptides and 70% as free amino acids) and CG hydrolysate P (CGHP group, 93% of protein as peptides and 7% as free amino acids). Body weight gain, adipose tissue weights, nitrogen balance, absorptions of energy, protein and fat, lipid profiles in plasma, liver and feces and hepatic activities of camitine palmitoyl transferase (CPT), fatty acid synthase (FAS), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PDH) were assessed. The CGHA diet had the highest amount of BCAAs, especially leucine, and most of them existed as free amino acid forms. The CGHA group showed significant weight reduction and negative nitrogen balance. Protein absorption and apparent protein digestibility in the CGHA group were significantly lower than those in other groups. Adipose tissue weights were the lowest in the CGHA group. Activity of CPT tended to be higher in the CGHA group than in other groups and those of FAS, ME and G6PDH were significantly lower in the CGHA group than in other groups. In conclusion, the CGHA diet which had relatively high amounts of free amino acids and BCAAs, especially leucine, had a weight reduction effect by lowering adipose tissue weight and the activities of FAS, ME and G6PDH in experimental animals, but it seemed to be a negative result induced by lowering protein absorption, increasing urinary nitrogen excretion and protein catabolism.

• 한국식품과학회지
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• 제21권4호
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• pp.492-497
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• 1989

천연식품성분에 의한 항산화기작을 해명하기 위하여 어육단백질, 탈지대두박, egg albumin 및 casein등의 단백질 가수분해물을 사용하여 linoleic acid 와의 모델계 반응을 통하여 이들의 항산화능과 ${\alpha}-tocopherol$과의 상승작용 및 금속이온 봉쇄능 등에 대하여 연구 검토하였는데 그 결과 각 단백질 가수분해물은 항산화능이 매우 큰 것으로 나타났으며. 특히 egg albumin가수분해물의 항산화능이 매우 강한 것으로 나타났다. 또한 천연항산화제인 ${\alpha}-tocopherol$과의 상승작용도 우수한 것으로 나타났는데 단백질 가수분해물간의 차이는 거의 없는 것으로 나타났다. 금속이온 봉쇄능 또한 높게 나타났으며 단백질 가수분해물의 금속이온 봉쇄능은 금속이온의 종류에 따라 다소 차이가 있는 것으로 나타났다.