Ethanol fermentation by a cellulolytic fungus Aspergillus terreus

The cellulolytic fungus Aspergillus terreus showed an additional property of fermenting glucose to ethanol. In addition to glucose, A. terreus also fermented other hexoses, pentoses and disaccharides to ethanol. Of the soluble carbon sources tested, glucose yielded maximum (2.46% (w/v)) ethanol.     

Disseminated Aspergillus terreus infection in a caged pigeon

Disseminated aspergillosis due to Aspergillus terreus was diagnosed in a young pigeon kept by a bird fancier. The fungus was isolated in heavy growth from the infected tissues on Sabouraud medium at 37 °C. Microscopic examination of the squeeze preparation of the air sacs revealed the presence of typical conidiophores of an Aspergillus sp. Histologically, branched, septate hyphae morphologically indistinguishable from Aspergillus were detected in the air sacs and lungs. The clinical, mycological and pathological findings are discussed. The role of A. terreus as an opportunistic pathogen should be studied in various clinical conditions of mammals and avians.     

Regulation of the cellulase biosynthesis inAspergillus terreus

Synthesis of cellulase inAspergillus terreus GTC826 was induced by glucose, xylose and cellobiose at up to 5.0 mg/ml but beyond this concentration they repressed enzyme synthesis. Cycloheximide at 0.2 mM prevented this induction.     

土曲霉致双外耳道曲霉病

目的报道1例发生在双外耳道的曲霉病。方法取双耳耵聍行真菌直接镜检,将耵聍接种到沙堡培养基培养,并对培养出的病原菌进行形态学鉴定和rDNA序列分析。结果耵聍真菌直接镜检阳性,耵聍在沙堡培养基25℃培养长出沙褐色菌落,28℃小培养后光镜及扫描电镜下见分生孢子头呈柱状,顶囊半球形,直径约10μm,小梗双层,两层小梗的长度无明显差别,平行紧密生长在顶囊的上2/3处。分生孢子呈球形,小而光滑。分生孢子梗壁光滑、透明。提取真菌总DNA用PCR方法扩增rDNA序列,测序后登录Gene Bank进行比对,该菌与土曲霉菌株ATCC1012 rDNA序列一致性达100%,鉴定为土曲霉。患者外用4%氟康唑注射液直接滴耳,2次/d,治疗1个月后痊愈。结论确诊1例双外耳道土曲霉病,局部应用氟康唑注射液治疗外耳道曲霉病有效。     

土生曲霉转化三七中药材的研究

从土壤真菌中筛选出直接转化中药材三七化学成分的菌株YM31966,经鉴定该菌株为土生曲霉(Aspergillus terreus).以固态转化方式,结合化学提取分离方法,通过高效液相色谱、核磁共振及质谱等波谱检测,该菌株转化三七产物由三七皂苷nR2 、RX1和人参皂苷Rg1、Rd、Rh1、Rh4构成主体成分,而原三七成分Rb1、Rc、Re和R1、R3,R6等物质被分解.结果表明,土生曲霉是一株能转化中药材三七的微生物,它具有改变原三七化学成分,形成新化合物,以及提高某些原化合物成分含量的作用.     

A macrokinetic modelling of the biosynthesis of lovastatin by Aspergillus terreus

In this work a simple kinetic model to describe the biosynthesis of lovastatin by Aspergillus terreus ATCC 20542 was proposed. Several series of experiments were conducted at different media compositions. The concentrations of C- and N-sources were changed over a wide range and so were the initial biomass concentrations. From these runs the relationships ruling the substrates uptake, biomass and product formation were learnt. Lovastatin biosynthesis appeared to be partly growth associated. The inhibitive effect of organic nitrogen on lovastatin biosynthesis was found and lactose appeared to be an important limiting substrate in the formation of lovastatin. The parameters of the model were evaluated on the basis of the kinetic data obtained in the separate experiments made in triplicate at two chosen media compositions. Other results obtained at different media compositions were independent of the ones mentioned above and used for the verification of the model. The validity of the model was also examined for the lactose-fed fed-batch run. Finally, a sensitivity analysis of the model parameters was performed. The formulated model, although relatively simplified, described the experimental data quite well and could be regarded as the background for further attempts to mathematically describe the process of lovastatin biosynthesis.     

Production of itaconic acid from pentose sugars by Aspergillus terreus

Itaconic acid (IA), an unsaturated 5‐carbon dicarboxylic acid, is a building block platform chemical that is currently produced industrially from glucose by fermentation with Aspergillus terreus. However, lignocellulosic biomass has potential to serve as low‐cost source of sugars for production of IA. Research needs to be performed to find a suitable A. terreus strain that can use lignocellulose‐derived pentose sugars and produce IA. One hundred A. terreus strains were evaluated for the first time for production of IA from xylose and arabinose. Twenty strains showed good production of IA from the sugars. Among these, six strains (NRRL strains 1960, 1961, 1962, 1972, 66125, and DSM 23081) were selected for further study. One of these strains NRRL 1961 produced 49.8 ± 0.3, 38.9 ± 0.8, 34.8 ± 0.9, and 33.2 ± 2.4 g IA from 80 g glucose, xylose, arabinose and their mixture (1:1:1), respectively, per L at initial pH 3.1 and 33°C. This is the first report on the production of IA from arabinose and mixed sugar of glucose, xylose, and arabinose by A. terreus. The results presented in the article will be very useful in developing a process technology for production of IA from lignocellulosic feedstocks. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1059–1067, 2017     

Purification and biochemical characterization of feruloyl esterases from Aspergillus terreus MTCC 11096

Aspergillus terreus MTCC 11096 isolated from the soils of agricultural fields cultivating sweet sorghum was previously identified to produce feruloyl esterases (FAEs). The enzymes responsible for feruloyl esterase activity were purified to homogeneity and named as AtFAE‐1, AtFAE‐2, and AtFAE‐3. The enzymes were monomeric having molecular masses of 74, 23 and 36 kDa, respectively. Active protein bands were identified by a developed pH‐dependent zymogram on native PAGE. The three enzymes exhibited variation in pH tolerance ranging between pH 5–8 and thermostability of up to 55°C. Inhibition studies revealed that the serine residue was essential for feruloyl esterase activity; moreover aspartyl and glutamyl residues are not totally involved at the active site. Metal ions such as Ca²⁺, K⁺, and Mg²⁺ stabilized the enzyme activity for all three FAEs. Kinetic data indicated that all three enzymes showed catalytic efficiencies (k_cat/K_m) against different synthesized alkyl and aryl esters indicating their broad substrate specificity. The peptide mass fingerprinting by MALDI/TOF‐MS analysis and enzyme affinity toward methoxy and hydroxy substituents on the benzene ring revealed that the AtFAE‐1 belonged to type A while AtFAE‐2 and AtFAE‐3 were type C FAE. The FAEs could release 65 to 90% of ferulic acid from agrowaste substrates in the presence of xylanase. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:924–932, 2013     

Identification of Potential Bioactive Compounds from Aspergillus terreus against HCV NS3 Serine Protease

This study was aimed to isolate bioactive compounds from the fermentation products of Aspergillus terreus, which could inhibit NS3 protease of hepatitis C virus (HCV). The bioactive compounds were isolated by reverse-phase silica-gel column chromatography, semi-preparative reversed-phase, and Sephadex LH-20, and then their structures were elucidated through spectroscopic analysis. As a result, two small molecule compounds were isolated. Compound 1 was identified as a new benzaldehyde, (E)-2,4-dihydroxy-6-propenylbenzaldehyde. Compound 2 was identified as pleurone, which was obtained from microorganisms for the first time. Their inhibitory activities against HCV NS3 protease (IC₅₀) were 32.6 μM and 78.9 μM, respectively. This study provided a new option for the development of anti-HCV drugs.     

黄河三角洲土曲霉Aspergillus terreus OUCMDZ-1925中具抗菌活性的聚酮类天然产物

作者利用化学与生物活性相集成的筛选方法,从采自黄河三角洲地区——东营黄河口的梭鱼Chelon haematocheilus的内脏中分离鉴定了1株耐盐真菌土曲霉Aspergillus terreus OUCMDZ-1925,其发酵产物具有抗枯草芽孢杆菌活性。进一步采用色谱分离、波谱鉴定,从其固体发酵(大米培养基)中分离鉴定了5个化合物,即右旋丁内酯I(1)、丁内酯IV(2)、丁内酯II(3)、丁内酯III(4)和3,5,6-三甲基-2,4-二羟基苯甲酸甲酯(5)。并发现化合物1–3和5对金黄色葡萄球菌(ATCC51650)有强的抑菌活性(最小抑菌浓度均为0.31μg/mL,阳性对照环丙沙星的最小抑菌浓度为0.16μg/mL),化合物1和2对产气杆菌(ATCC13408)以及化合物1和3对枯草芽孢杆菌(ATCC93151)有中等的抑菌活性(最小抑菌浓度分别为6.25μg/mL和12.50μg/mL,阳性对照环丙沙星的最小抑菌浓度分别为1.25μg/mL和5.0μg/mL),化合物1–5对大肠杆菌(ATCC25922)以及化合物4对金黄色葡萄球菌(ATCC51650)有弱的抑制活性,且化合物1的产量高,达2.5g/kg,为其后续研究提供了新的药源。     

An anti-inflammatory isoflavone from soybean inoculated with a marine fungus Aspergillus terreus C23-3

ABSTRACT

A new isoflavone derivative compound 1 (psoralenone) was isolated from soybean inoculated with a marine fungus Aspergillus terreus C23-3, together with seven known compounds including isoflavones 2–6, butyrolactone I (7) and blumenol A (8). Their structures were elucidated by MS, NMR, and ECD. Psoralenone displayed moderate in vitro anti-inflammatory activity in the LPS-induced RAW264.7 cell model. Compound 2 (genistein) showed moderate acetylcholinesterase (AChE) inhibitory activity whereas compounds 2, 5 (biochanin A), 6 (psoralenol), and 7 exhibited potent larvicidal activity against brine shrimp. Compounds 3 (daidzein), 4 (4?-hydroxy-6,7-dimethoxyisoflavone), and 5–7 showed broad-spectrum anti-microbial activity, and compound 7 also showed moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity.     

稻瘟净（Blasticidin S）脱氨酶基因的克隆

从一株抗稻瘟净（ＢＳ）的Ａｓｐｅｒｇｉｌｌｕｓ ｔｅｒｒｅｕｓ菌中克隆到一个ｂｌａｓｔｉｅｉｄｉｎＳ脱氨酶基因,命名为ｂｓｒＡＳ。ＤＮＡ序列分析表明ｂｓｒＡＳ不含内含子。编码区长３９０ｂｐ,编码１３０个氨基酸。将ｂｓｒＡＳ转化到稻瘟菌中,能使受体菌表达出ＢＳ脱氨酶的活性,从而产生抗药性。该基因可作为抗药标记基因使用,建立稻瘟菌的基因转化系统。     

泰国红树内生真菌土曲霉xy03菌株中新杂萜类成分

采用硅胶柱层析、SephadexLH-20凝胶柱层析和高效液相色谱(HPLC)等技术,从一株红树马六甲木果楝来源的土曲霉Aspergillus terreusxy03的发酵物中分离得到了7个杂萜类化合物:asptercin A(1)、(1R,4aR,6aR,12aR,12bS)-1,3,4,4a,5,6,6a,12,1...     

Lovastatin and (+)‐geodin production by Aspergillus terreus from crude glycerol

The use of pure substrate represents a significant proportion of the cost of manufacturing a drug such as lovastatin. This study explores the production of lovastatin and (+)‐geodin by Aspergillus terreus ATCC 20542 using biodiesel‐derived crude glycerol (CG) as a feedstock. Shake flask experiments showed reduced lovastatin production and glycerol consumption in the presence of 10–50 g/L CG with respect to pure glycerol controls. At 50 g/L, lovastatin and (+)‐geodin production was significantly reduced by 82 and 73%, respectively. The lowest lovastatin inhibition was detected in 30 g/L of CG (48%), which was accompanied by a significant rise in (+)‐geodin production (338%). Further investigation was performed on three major impurities found in CG, namely methanol (MeOH), sodium chloride (NaCl), and fatty acids (oleic acid and palmitic acid (PA), soap). None was particularly inhibitory for lovastatin, except soap and PAs, which reduced its production by more than 50% at all concentrations tested. In contrast, (+)‐geodin was inhibited in the presence of MeOH and PA by up to 46 and 91%, respectively. These observations indicate that partial purification of CG would be potentially useful in improving production of lovastatin and (+)‐geodin by A. terreus.     

Adding talc microparticles to Aspergillus terreus ATCC 20542 preculture decreases fungal pellet size and improves lovastatin production

Changing fungal morphology with the use of morphological engineering techniques leads to improving the production of metabolites by filamentous fungi in the submerged culture. Adding mineral microparticles is one such simple method to change fungal pellet size. Here, it was studied for a lovastatin producer, Aspergillus terreus ATCC 20542. The experiments were conducted in shake flasks and 10 μm talc microparticles were added to the preculture. Intrapellet oxygen concentration profiles were determined by an oxygen microprobe. Talc microparticles caused a decrease of A. terreus pellets diameter from about 2000 to 900 μm, dependent on their concentration in the preculture. Smaller pellets produced more lovastatin, whose titre exceeded then 120 mg L^?1, utilising more lactose. The decrease in pellet size resulted in changes of oxygen concentration profiles in the pellets. The estimated critical pellet diameter, at which the non‐oxygenated zone was observed in the centre of the pellets, was 1700 μm. Smaller pellets were fully penetrated by oxygen. To conclude, facilitated diffusion of oxygen into the pellets of smaller diameter and their less dense structure made lactose utilisation by A. terreus more efficient, which ultimately increased lovastatin production in the runs with talc microparticles added, compared to the control runs.     

嗜热糖化酶基因在重组黑曲霉工程菌中的表达及酶学性质初步研究

为了提高糖化酶的耐热性能,降低淀粉糖化发酵工艺的生产成本,构建了同源整合载体pEasy-glaAdir以及pEasyssg,将黑曲霉(Aspergillus niger)的糖化酶基因(glaA)灭活,并将硫磺矿硫化叶菌(Sulfolobus solfataricus)的嗜热糖化酶基因(ssg)插入到黑曲霉基因组中,筛选得到表达嗜热糖化酶的重组黑曲霉工程菌(A.nigerWW1)。重组菌的发酵结果显示,嗜热糖化酶在黑曲霉中得到了分泌表达,发酵液酶活达到3 030 U/mL。重组嗜热糖化酶的最适反应温度为90℃,最适pH为6.0,该酶具有较高的热稳定性,在80℃时的半衰期在60 min以上,具有良好的工业应用前景。     

两性霉素B抗真菌作用机制与病原性土曲霉对其耐药机制的研究进展

两性霉素B(amphotericin B,AMB)是经典的多烯类抗真菌药物,对病原真菌具有广谱抗菌活性,且不易产生耐药性.土曲霉是临床上常见的病原性曲霉,因其对AMB天然耐药而受到关注.现阶段,AMB的抗真菌作用机制有待进一步阐明,且真菌对AMB的耐药机制研究亦不充分.本文就AMB在土曲霉中诱导内源性活性氧(react...     

过表达LaeA激活海洋土曲霉中isoflavipucine类化合物的合成及其抗弧菌活性研究

丝状真菌土曲霉因产生结构独特且药理活性强烈的次级代谢产物而受到真菌学家和药学家的广泛关注。然而,在丝状真菌中,大部分次级代谢基因在常规实验室培养条件下表达量较低甚至沉默。本研究通过过表达全局性调控因子LaeA试图激活一株海洋来源土曲霉中的沉默基因簇以发现新次级代谢产物。结果表明,laeA基因过表达突变中未知产物基因簇被激活,指纹图谱分析发现了2个在野生菌株不存在的化合物吸收峰。质谱和核磁共振波谱分析确证了这2个化合物为dihydroisoflavipucine类小分子,特别是化合物1的产量在突变体中高达183 mg/L。此外,抗菌活性测试发现,这2个化合物对4种病原弧菌显示了强烈的活性,特别是化合物1抗弧菌活性更强,MIC低至16μg/mL。本研究提供了一条大量合成dihydroisoflavipucine类抗生素的新路线,并证明了次级代谢调控因子LaeA在丝状真菌中的功能是高度保守的,过表达LaeA是激活丝状真菌中沉默基因簇的有效手段。