• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1041-1046
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• 2006

Selenium-containing peptide (selenium peptide) was produced by autolysis of total proteins of Saccharomyces cerevisiae grown with inorganic selenium. Selenium peptide exhibited antioxidant activity as a glutathione peroxidase (GPx) mimic, and its activity was dependent on the hydrolysis methods. The GPx-like activity of the hydrolyzed selenium peptide increased 2.7-folds when digested by protease, but decreased by acid hydrolysis. During the autolysis of the yeast cell, the GPx-like activity and selenium content increased 4.3- and 2.3-folds, respectively, whereas the average molecular weight (MW) of selenium peptide decreased 70%. The GPx-like activity was dependent on the MW of selenium peptide and was the highest (220 U/mg protein) at 9,500 dalton. The maximum GPx-like activity (28,600 U/g cell) was obtained by 48 h of autolysis of the cells, which were precultured with 20 ppm of selenate. Selenium peptide showed little toxicity, compared with highly toxic inorganic selenium. These results show the potential of selenium peptide as a nontoxic antioxidant that can be produced by simple autolysis of yeast cells.

• Asian-Australasian Journal of Animal Sciences
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• 제9권3호
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• pp.303-307
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• 1996

The degree of autolysis and presence of cell-wall degrading enzymes in an anaerobic ruminal fungus, Piromyces communis OTSI, grown in liquid medium, was monitored to evaluate the effect of self-digestion on fungal biomass. After a 30 days incubation period fungal dry weight decreased by 45% and the cell wall component chitin decreased by 22%. Chitinase activity detected in the supernatant was mainly of the endotype and peaked at day 6 of the incubation. ${\beta}-1$, 3-glucanase was detected from day 4 and increased throughout the incubation period. Autolysis was a slow process, and under natural conditions it is unlikely that it plays a significant role in the degradation of the spent fungal vegetative stage in the rumen.

• 미생물학회지
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• 제27권4호
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• pp.357-365
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• 1989

고온성 Clostridium thermohydrosulfioicum의 autolysis 및 autoplast 형성에 대하여 조사하였다. 초기대수증식기 상태의 세포가 $K^{+}$ $Na^{+}$등의 1가이온을 함유한 buffer나 Tris-HCl buffer 속에서 autolysis 현상을 나타내었다. 이 현상은 1가이온이나 cysteine-HCl, sorbitol, glycerol 등의 화학물질이 존재할 때 강하게 촉진되었으나 $Mg^{2+},Mn^{2+},Ca^{2+},Ni^{2+}$등의 2가 이온에 의해 다소 저해되었으며, 특히 $Fe^{2+},Cu^{2+}$ 등의 2가이온 및 citric acid에 의해서는 강하게 저해되었다. 또한 세포벽합성 저해제인 ampicillin을 함유한 배지에서 생육한 세포는 autolysis가 촉진되었으나 핵산 및 단백질합성 저해제의 경우 autolysis가 저해되었다. Autolysis가 유도되는 최적 pH는 7.5, 최적 온도는 $60^{\circ}C$였다. 한편, autolysis가 일어나는 도중, $Mg^{2+}, Mn^{2+}, Ca^{2+}, Ni^{2+}$등의 2가 이온에 의해 원형질막이 안정화 될 때 lysozyme의 첨가없이 autoplast가 형성되었다. 이 autoplast는 대수증식기 말기 세포에서 형성이 잘 되었으며, autoplast 형성의 최적 pH는 7.5, 최적 온도는 $37^{\circ}C$, 최적 $MgCl^{2}$ 농도는 20mM이었으며, 화학물질로는 0.3M glycerol이 효과적이었다.

• KSBB Journal
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• 제19권4호
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• pp.245-249
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• 2004

천연 식품 소재로 널리 사용되는 효모 추출물을 제조하는 공정의 개선을 위하여 제빵용 효모를 이용하여 자기소화법과 효소처리법을 병용하여 효모 추출물을 제조하였다. NaCl과 에탄올이 효모의 자기소화에 영향을 미치는 인자이었으며 최적 첨가량은 각각 3%와 1%이었다. 효모의 열처리와 효모 세포벽 분해효소의 사용은 유의하지 않았다. 효모를 자기소화 시킨 후 단백질 분해효소와 핵산 분해효소를 처리하고 Maillard 반응과 debittering 공정을 거쳐 효모 추출물을 제조하였다. 최종적으로 얻어진 효모 추출물의 수율은 고형분 기준으로 76%, 총 질소 기준으로 59%이었다. 맥주 효모를 이용한 결과와 비교하면 제빵용 효모를 이용하는 것이 맥주 효모를 이용하는 것보다 수율면에서도 유리하였다.

• 미생물학회지
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• 제41권4호
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• pp.312-315
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• 2005

먹물버섯의 하나인 Coprinellus congregatus에서는 자실체가 성숙된 후 곧 자가분해되어 먹물로 전환된다. 이 자가분해 과정과 관련된 가수분재 효소의 역할을 이해하기 위한 첫 단계로서, 자가분해과정과 연관된 미세구조의 변화를 전자현미경으로 조사하였다. 자실체의 성숙과정에서 자실층과 자실하층에 존재하는 모든 세포질은 새로운 포자의 형성을 위하여 포자로 이동되는 것으로 보인다. 조직 내의 세포질의 고갈과 포자의 완성은 조직 내의 세포벽의 분해를 야기하는 것으로 보이며, 자실층과 자실하층의 세포벽은 동시적으로 분해 되는 것으로 생각된다. 본 연구는 먹물버섯의 자가분해가 세포질의 분해가 아닌 세포벽의 분해과정에 의한 것임을 보여 주었으며, chitin 분해효소와 같은 가수분해 효소의 중요성을 제시하였다.

• 한국미생물·생명공학회지
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• 제25권5호
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• pp.512-519
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• 1997

RNA accumulating strain of Torulopsis versatilis MT-1 was cultured in molasses medium for higher contents of RNA in cell. Yeast cells were harvested at logarithmic phase on synchronous culture. Yield of cells on dry base to input sugar was 59.5%. Crude protein content was 55.1% in cell. RNA content was 13.9%. Some problems found in the process for the preparation of yeast extracts were improved by the addition of culture broth of Streptomyces faecalis MSF which secrete RNase (5' nuclease and 5' adenylic acid deaminase). When the culture broth of S. faecalis MSF was added in autolysis process 46% of RNA in cell was converted to I and G(5' inosinic acid and 5' guanylic acid) in extract. By addition of 3-7% culture broth of S.faecalis MSF in autolysis or enzymolysis process at the start or early stage, RNA in extract was converted easily to I and G and protein in cells was easily extracted and hydrolyzed to amino acid. Taste of those yeast extracts was delicious. The yeasty smell in yeast extracts was removed. And cell debris was easily removed from extract.

• 한국미생물·생명공학회지
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• 제43권3호
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• pp.249-258
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• 2015

In this paper, the autolysis process of Saccharomyces cerevisiae FX-2 (S. cerevisiae FX-2) via, a variety of endogenous enzyme, was investigated systematically by analyzing changes in physicochemical parameters in autolysate, surface morphology and the internal structure of the yeast cells. As an explicit conclusion, the arisen autolysis depended on the pH and the optimal pH was found to be 5.5. Based on the experimental data and the characteristics of mycelia morphology, a hypothesis is put forward that simple proteins in yeast vacuolar are firstly degraded for utilization, and then more membrane-bound proteins are hydrolyzed to release hydrolytic enzymes, which arouse an enzymatic reaction to induce the collapse of the cell wall into the cytoplasm.

• Journal of Veterinary Science
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• 제25권3호
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• pp.24.1-24.9
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• 2024

Importance: In veterinary forensic science, accurately determining the postmortem interval (PMI) is crucial for identifying the causes of animal deaths. Autolysis, a significant postmortem process, influences PMI estimation, but its relationship with humidity is not well understood. Objective: This study aimed to improve the accuracy of PMI estimates in veterinary forensic cases by looking into how different humidity levels affect autolysis in different organs of rats. Methods: The study involved 38 male rats, examining histopathological changes in their heart, liver, and pancreas. These organs were subjected to controlled humidity levels (20%, 55%, and 80%) at a constant 22℃. Tissue samples were collected at several intervals (0 h, 12 h, 24 h, 3 days, and 8 days) for comprehensive analysis. Results: Distinct autolytic characteristics in animal organs emerged under varying humidity conditions. The low-humidity environment rapidly activated autolysis more than the high-humidity environment. In addition, it was found that lower humidity caused nuclear pyknosis, cytoplasmic disintegration, and myofiber interruption. The liver, in particular, showed portal triad aggregation and hepatocyte individuation. The pancreas experienced cell fragmentation and an enlarged intracellular space. High humidity also caused the loss of striations in cardiac tissues, and the liver showed vacuolation. Under these conditions, the pancreas changed eosinophilic secretory granules. Conclusions and Relevance: The study successfully established a clear connection between the autolytic process in PMIs and relative humidity. These findings are significant for developing a more accurate and predictable method for PMI estimation in the field of veterinary forensic science.

• Journal of Microbiology and Biotechnology
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• 제19권9호
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• pp.932-945
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• 2009

Several species of Gram-positive bacteria have cell wall peptidoglycan (syn. murein) in which not all of the sugar moieties are N-acetylated. This has recently been shown to be a secondary effect, caused by the action of a peptidoglycan N-acetylglucosamine deacetylase. We have found that the opportunistic pathogen Listeria monocytogenes is unusual in having three enzymes with such activity, two of which remain in the cytoplasm. Here, we examine the enzyme (PgdA) that crosses the cytoplasmic membrane and is localized in the cell wall. We purified a hexa-His-tagged form of PgdA to study its activity and constructed a mutant devoid of functional Lmo0415 (PgdA) protein. L. monocytogenes PgdA protein exhibited peptidoglycan N-acetylglucosamine deacetylase activity with natural substrates (peptidoglycan) from both L. monocytogenes and Escherichia coli as well as the peptidoglycan sugar chain component N-acetylglucosamine, but not with N-acetylmuramic acid. As was reported recently [6], inactivation of the structural gene was not lethal for L. monocytogenes nor did it affect growth rate or morphology of the cells. However, the pgdA mutant was more prone to autolysis induced by such agents as Triton X-100 and EDTA, and is more susceptible to the cationic antimicrobial peptides (CAMP) lysozyme and mutanolysin, using either peptidoglycan muramidases or autolysis-inducing agents. The pgdA mutant was also slightly more susceptible than the wild-type strain to the action of certain beta-lactam antibiotics. Our results indicate that protein PgdA plays a protective physiological role for listerial cells.

• Journal of Microbiology
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• 제45권6호
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• pp.593-596
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• 2007

In this study, we describe the development of a simple and efficient method for cell lysis via the insertion of a bacteriophage lambda lysis gene cluster into the pET22b expression vector in the following order; the T7 promoter, a gene for a target protein intended for production, Sam7 and R. This insertion of R and Sam7 into pET22b exerted no detrimental effects on cellular growth or the production of a target protein. The induction of the T7 promoter did not in itself result in the autolysis of cells in culture but the harvested cells were readily broken by freezing and thawing. We compared the efficiency of the cell lysis technique by freezing and thawing to that observed with sonication, and determined that both methods completely disintegrated the cells and released proteins into the solution. With our modification of pET22b, the lysis of cells became quite simple, efficient, and reliable. This strategy may prove useful for a broad variety of applications, particularly in experiments requiring extensive cell breakage, including library screening and culture condition exploration, in addition to protein purification.