• 한국균학회지
• /
• 제12권4호
• /
• pp.141-152
• /
• 1984

1. 검정곰팡이 (Aspergillus niger)를 실험재료로 하여 동조적으로 액침배양한 결과 포자의 발아로 부터 균사의 생장, 생식기관의 성숙 및 무성포자의 형성까지를 재현시킬 수 있었다. 2. 각 분화과정에서의 균체로 부터 고인산화뉴를레오티드를 추출하여 P.E.I. Cellulose TLC법으로 전개시켰다. 3. 포자형성 직전의 균체로 부터 얻은 추출물 중에 구아노신테트라포스페이트 $(GP_4)$가 존재함을 확인하였다. 4. 분화과정에 따른 균체로부터 추출한 유리아미노산의 총량은 포자형성 직전에 급격히 증가함을 알았다. 5. 정낭과 경자가 완성된 균체에 8-아자구아닌과 시클로헥시미드를 처리한 바 포자형성이 억제되었다. 6. 전낭과 경자가 완성된 균체에 이노신산과 구아닌산을 처리한 바 포자형성이 촉진되었다.

• 미생물학회지
• /
• 제45권4호
• /
• pp.312-317
• /
• 2009

사상성 모델 진균인 Aspergillus nidulans에 존재하는 forkhead 유전자들의 구조와 기능을 체계적으로 연구하기 위해 유전체 분석을 통해 forkhead 도메인을 가지고 있는 6개의 forkhead 유전자를 발견하였다. 이들 중 4개의 유전자들은 다른 진균에서 발견되는 forkhead 유전자들과 전반적인 유사성이 있었으나, 2개의 유전자들은 다른 종에서는 보존되어있지 않은 A. nidulans 특이적인 유전자들이었다. A. nidulans 특이적 forkhead 유전자들 중 하나인 fkhF(AN8949.2) 유전자는 염색체 7번에 위치하고 있고, ORF는 2,337 bp로 구성되어 있으며 778개의 아미노산을 암호화하고 있는 것으로 추정되었다. 예상되는 FkhF 단백질의 N-말단 부위에 보존된 forkhead 도메인을 가지고 있었으며, 이 유전자의 기능을 분석하기 위해 유전자제거 돌연변이 균주를 제조하였다. fkhF 유전자 결손돌연변이주는 유성분화 유도 조건 등을 포함한 여러 고체배지 배양 조건에서 유성분화에는 영향을 미치지 않았으나 무성포자병(conidiophore)의 생성 밀도와 성숙도에 영향을 주는 것으로 관찰되었고, 야생형과 달리 진탕배양시에 무성포자병을 형성함이 관찰되었다. 이는 fkhF 유전자가 A. nidulans의 부적절한 무성분화를 억제하고 정상적인 무성포자 성숙과정에 관여하는 유전자라는 것을 보여준다.

• Journal of Applied Biological Chemistry
• /
• 제62권2호
• /
• pp.157-165
• /
• 2019

Di- and tri-methylation of lysine 4 on histone H3 (H3K4me2 and H3K4me3, respectively) are epigenetic markers of active genes. Complex associated with Set1 (COMPASS) mediates these H3K4 methylations. The involvement of COMPASS activity in secondary metabolite (SM) biosynthesis was first demonstrated with an Aspergillus nidulans cclA knockout mutant. The cclA knockout induced the transcription of two cryptic SM biosynthetic gene clusters, leading to the production of the cognate SM. Monascus spp. are filamentous fungi that have been used for food fermentation in eastern Asia, and the pigment Monascus azaphione (MAz) is their main SM. Monascus highly produces MAz, implying that the cognate biosynthetic genes are highly active in transcription. In the present study, we examined how COMPASS activity modulates MAz biosynthesis by inactivating Monascus purpureus cclA (Mp-cclA) and swd1 (Mp-swd1). For both ${\Delta}Mp-cclA$ and ${\Delta}Mp-swd1$, a reduction in MAz production, accompanied by an abated cell growth, was observed. Suppression of MAz production was more effective in an agar culture than in the submerged liquid culture. The fidelity of the ${\Delta}Mp-swd1$ phenotypes was verified by restoring the WT-like phenotypes in a reversion recombinant mutant, namely, trpCp: Mp-swd1, that was generated from the ${\Delta}Mp-swd1$ mutant. Real-time quantitative Polymerase chain reaction analysis indicated that the transcription of MAz biosynthetic genes was repressed in the ${\Delta}Mp-swd1$ mutant. This study demonstrated that MAz biosynthesis is under the control of COMPASS activity and that the extent of this regulation is dependent on growth conditions.

• Journal of Microbiology and Biotechnology
• /
• 제29권4호
• /
• pp.587-595
• /
• 2019

Pharmacological research on (CHA), a marine-derived quinazolinone alkaloid with significant cytotoxic activity, is restricted by low yields and is a problem that needs to be settled urgently. In this work, the selection of additional nitrogen sources and the optimization of additional concentrations and longer fermentation times using ammonium acetate, were investigated. CHA production was optimized to 62.1 mg/l with the addition of 50 mM ammonium acetate at 120 h of the fermentation in the shaker flask. This feeding strategy significantly increased 3-deoxy-arabino-heptulosonate-7-phosphate synthase activity and transcript levels of critical genes (laeA, dahp, and trpC) in the shikimate pathway compared with the non-treatment group. In addition, the selection of the feeding rate (0.01 and $0.03g/l{\cdot}h$) was investigated in a 5-L bioreactor. As a result, CHA production was increased by 57.9 mg/l with a $0.01g/l{\cdot}h$ ammonium acetate feeding rate. This work shows that the strategy of ammonium acetate supplementation had an effective role in improving CHA production by Aspergillus fumigatus CY018. It also shows that this strategy could serve as an important example of large-scale fermentation of a marine fungus in submerged culture.

• 한국미생물·생명공학회지
• /
• 제19권2호
• /
• pp.140-146
• /
• 1991

Mutation experiments were performed to select the mutant of Aspergillus niger 55, which had lost almost all the ability to produce transglucosidases but retained that of high productivity of raw meal saccharifying enzyme, by means of successive induction with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), ultraviolet(UV) light, and ${\gamma}$-rays. Also, we used the mutant enrichment techniques, such as liquid culture-filtration procedure and differential heat sensitivity of conidia, in order to increase the possibility of obtaining a mutant. The glucoamylase productivity of mutant PFST-38 was 11 times higher than that of the parent strain. The mutant PFST-38 was morphologically identical to the parent strain, except for the size of conidia, the tendency to form conidia and the lenght of conidiophore. Asp. niger mutant PFST-38 apeared to be useful for the submerged production of the raw corn meal saccharifying enzyme.

• Journal of Microbiology and Biotechnology
• /
• 제14권6호
• /
• pp.1170-1175
• /
• 2004

The involvement of the relA and rsh genes in the morphological and physiological differentiation of Streptomyces clavuligerus was evaluated with the relA and rsh genes mutants. The morphological differentiation of S. clavuligerus was greatly affected by the disruption of the relA gene, but not very much by the disruption of the rsh gene. The altered morphological characteristics were completely restored by the complementation of the corresponding disrupted genes. Thus, it was apparent that the mycelial morphology and clavulanic acid production were severely affected by the disruption of the relA gene. Production of clavulanic acid in the submerged batch culture and glycerol-limited chemostat showed that production was inversely related to the specific growth rate in the wild-type strain. However, the production of clavulanic acid in the ${\Delta}relA$ and ${\Delta}rsh$ null mutants was completely abolished. Therefore, it seems plausible that the stringent response of S. clavuligerus to starvation for amino acids is governed mainly by ReIA, rather than Rsh, and that the (p)ppGpp synthesized immediately after the depletion of amino acids triggers the initiation of pathways for both morphological and physiological differentiation in this species.

• 한국미생물·생명공학회지
• /
• 제18권6호
• /
• pp.547-552
• /
• 1990

산업적인 응용을 위한, 생 전분 분해력이 높고 액체 배양에 적용 가능한 균을 토양으로부터 분리한 결과, 옥수수 생 전분 당화 효소 생산력이 높은 곰팡이 No.55 균주를 분리하고 이 균주의 형태적, 생리적, 배양특성을 조사, 균 동정을 행한 결과 No.55 분리균은 Aspergillus niger 또는 그 유연균으로 동정되었다.

• 한국미생물·생명공학회지
• /
• 제7권1호
• /
• pp.31-36
• /
• 1979

배양된 색소액으로부터 조색소의 생산, 물리적 성질, 생리적 성질을 조사하여 다음과 같은 결론을 얻었다. 1) 유기용매를 이용하여 Petroleum ether에서 황색계 조색소, 60％ ethanol에서 적색계 조색소를 얻었으며 배양액 100ml당 적색조색소 400mg, 황색조색소가 80 mg 정 도 생산되었다. 2) 배양된 색소액의 흡광도곡선은 495∼500nm에서 최대 흡광도를 나타내었고 균사체를 파괴하여 추출한 균체내 색소의 최대 흡광도는 394∼403nm이었다. 3) Thin layer Chromatography에 의한 적색계 색소는 5가지 색소물질로 구성되어 있었고 황색계 색소는 1가지였으며 pH 안정성은 pH 3에서 pH 9까지 비교적 안정하였다. 4) 추출한 색소액의 용혈반응시험은 음성이었고 적색조색소의 항균력시험은 감수성이 없었으며 급성 시험의 결과에서는 독성이 없었다.

• 한국균학회지
• /
• 제8권3호
• /
• pp.159-166
• /
• 1980

검정곰팡이(Aspergillus niger)의 동조적(同調的) 분화(分化)를 시행(施行)하면서 acid-phenol 용성(溶性)인 세포단백질(細包蛋白質)을 추출(抽出)하여 포자형성(胞子形成) 전후(前後)의 단백상(蛋白像)의 변화(變化)를 polyacrylamide gel 전기영동법(電氣泳動法)으로 추구(追究)하였다. 결과(結果)에서 1종(種)의 단백질(蛋白質)(분자량(分子量) 약(約) 27,000 정도(程度))이 포자형성기(胞子形成期)에 신생(新生)함을 알았다. 포자(胞子)의 발아시(發芽時)에는 18개의 단백질(蛋白質)밴드가 있으며 포자형성시(胞子形成時)에는 19개가 있었다. Amido black 색소(色素)의 염색도(染色度)는 분화시기(分化時期)에 따라서 각(各) 밴드마다 각각 많이 달랐다.

• KSBB Journal
• /
• 제26권1호
• /
• pp.33-40
• /
• 2011

Anti-diabetic effect of the exopolysaccharides (EPS) produced from submerged mycelial culture of Cordyceps sinensis (Cs) was studiedin a type II diabetic animal model (C57BL/6J ob/ob). This study was designed to determine whether Cs-EPS improves clinical symptoms of type II diabetes in ob/ob mice. After Cs-EPS treatment at doses of 200 mg/kg body weight, the fasting blood glucose levels decreased by 47% after 7 weeks compared with those of the control mice. According to the oral glucose tolerance test, the glucose levels recovered its baseline after 120 min in Cs-EPS-treated mice, although the blood glucose levels increased significantly after 30 min. On the other hand, the control group (not-treated) did not recovered its initial level of glucose after 120 min. Furthermore, food intake, body weight, total plasma cholesterol and triglyceride concentrations in ob/ob mice treated with Cs-EPS were significantly decreased, compared with those in control ob/ob mice. Cs-EPS treatment increased significantly the plasma insulin level and the expression of leptin mRNA in adipose tissue of Cs-EPS-treated ob/ob mice. From these results, it is demonstrated that Cs-EPS could be effective for regulating normal blood glucose levels by increasing the amounts of plasma insulin and leptin expression in ob/ob mice, indicating that this compound could be a candidate material as a dietary supplement to control hyperglycemia in patients suffering from type II diabetes.