Pathway and rate-limiting step of glyphosate degradation by Aspergillus oryzae A-F02

Aspergillus oryzae A-F02, a glyphosate-degrading fungus, was isolated from an aeration tank in a pesticide factory. The pathway and rate-limiting step of glyphosate (GP) degradation were investigated through metabolite analysis. GP, aminomethylphosphonic acid (AMPA), and methylamine were detected in the fermentation liquid of A. oryzae A-F02, whereas sarcosine and glycine were not. The pathway of GP degradation in A. oryzae A-F02 was revealed: GP was first degraded into AMPA, which was then degraded into methylamine. Finally, methylamine was further degraded into other products. Investigating the effects of the exogenous addition of substrates and metabolites showed that the degradation of GP to AMPA is the rate-limiting step of GP degradation by A. oryzae A-F02. In addition, the accumulation of AMPA and methylamine did not cause feedback inhibition in GP degradation. Results showed that degrading GP to AMPA was a crucial step in the degradation of GP, which determines the degradation rate of GP by A. oryzae A-F02.     

Colonization and Biodegradation of Photo-Oxidized Low-Density Polyethylene (LDPE) by New Strains of Aspergillus sp. and Lysinibacillus sp.

The primary objective of this study was the isolation of low-density polyethylene (LDPE)-degrading microorganisms. Soil samples were obtained from an aged municipal landfill in Tehran, Iran, and enrichment culture procedures were performed using LDPE films and powder. Screening steps were conducted using linear paraffin, liquid ethylene oligomer, and LDPE powder as the sole source of carbon. Two landfill-source isolates, identified as Lysinibacillus xylanilyticus XDB9 (T) strain S7-10F and Aspergillus niger strain F1-16S, were selected as super strains. Photo-oxidation (25 days under ultraviolet [UV] irradiation) was used as a pretreatment of the LDPE samples without pro-oxidant additives. The PE biodegradation process was performed for 56 days in a liquid mineral medium using UV-irradiated pure LDPE films without pro-oxidant additives in the presence of the bacterial isolate, the fungal isolate, and the mixture of the two isolates. The process was monitored by measuring the fungal biomass, the bacterial growth, and the pH of the medium. During the process, the fungal biomass and the bacterial growth increased, and the pH of the medium decreased, which suggests the utilization of the preoxidized PE by the selected isolates as the sole source of carbon. Carbonyl and double bond indices exhibited the highest amount of decrement and increment, respectively, in the presence of the fungal isolate, and the lowest indices were obtained from the treatment of a mixture of both fungal and bacterial isolates. Fourier transform infrared (FT-IR), x-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses showed that the selected isolates modified and colonized preoxidized pure LDPE films without pro-oxidant additives.     

Alcohol oxidase of Aspergillus flavipes grown on hexadecanol

Abstract: The activity of alcohol oxidase in Aspergillus flavipes was induced by growth on hexadecanol, though highest activities were obtained using a mixture of hexadecanol and olive oil. The enzyme showed a wide range of substrate specificity towards aliphatic primary alcohols from C₈ to C₁₈. The preferred substrate was decanol. The enzyme had an optimum pH of 9.5. It also used cis -unsaturated alcohols better than the trans -isomers. ω-Hydroxy fatty acids and α,ω-diols were not attacked.     

金属离子对黄柄曲霉生长和抗真菌抗生素合成的影响

不同的金属离子对兼性海洋霉菌黄柄曲霉179的生长有不同的影响。在0．002mol/L的浓度下,Hg^2 、Ag^ 和Cr^3 能强烈抑制该菌的生长,Pb^2 、Sr^2 、Co^2 、Al^3 对其生长有一定的抑制,生长量低于对照;Mn^2 、Ba^2 、Zn^2 对其生长没有明显影响;Cu^2 对该菌的生长有微弱的促进作用。菌体生物量略高于对照;不同的金属离子对曲霉179真菌抗生素179M合成有不同的影响。与对照相比,Ba^2 对共产量没有影响;Al^3 、Zn^2 、Sr^2 有一定的抑制作用,其发酵相对效价分别为对照的81．4％、55．5％和65％;0．002mol／L斩Mn^2 和Pb^2 能强烈抑制此抗生素的合成,在添加0．002mol/LMn^2 和Pb^2 的培养基中,虽然菌体生长良好,但无179M产生;Co^2 和Cu^2 则有明显的促进作用,当培养基中添加0．002ml／L的Co^2 时其发酵相对效价提高到261．4％;当培养基中添加0．003mol／L的Cu^2 时其发酵相对效价提高到350．2％。Co62 和Cu62 对发酵的促进效应是相互拮抗的。     

米蛋白分解菌A.0—6的菌种鉴定及其与米曲霉As.3.951菌株的比较

为了进一步认识经多年选育得到的Ａ·０—６米蛋白分解菌,对其进行了形态及培养特性和生理特性的研究试验,认为Ａ·０—６菌株为半知菌类,丛梗孢目,丛梗孢科,曲霉属,黄曲霉群的米曲霉。与在酿造工业生产上应用多年的米曲霉Ａｓ．３．９５１相比,Ａ·０—６菌株具有蛋白酶活力高,米蛋白分解能力强,生长快,易培养等特点,是值得推广应用的优良菌株。     

米曲霉两株营养缺陷型原生质体的形成和再生的条件实验*

采用1%溶壁酶加1%玛瑙螺酶(褐云玛瑙螺消化液的冷冻干粉)的混合酶,自米曲霉(Aspergillus oryzae)的两株营养缺陷型中获得了大量的原生质体,并比较了渗透压稳定剂、温度、菌丝体的培养基成分等因素对原生质体形成和再生的作用。无机盐类稳定剂(NaCl、KCl)获得了高产量的原生质体,而有机类(蔗糖、甘露醇、山梨醇)做为稳定剂不甚理想。对120和720菌株的原生质体在高渗再生培养基上进行再生试验,再生率分别为52%和65%。     

黄曲霉和米曲霉的多相鉴定方法

【背景】黄曲霉(Aspergillus flavus)和米曲霉(Aspergillus oryzae)形态特征相近,基因组高度相似,较难区分。【目的】旨在总结一套准确鉴别二者的分类方法。【方法】利用22株标准菌株对传统形态学、产毒培养基、酶联免疫毒素检测、系统发育分析、产毒基因检测等5种鉴别方法分别进行验证。【结果】各鉴定方法的结果存在异同,单一的鉴定方法容易出现假阴性或假阳性结果。【结论】利用单一方法区分黄曲霉和米曲霉具有潜在风险,多相鉴定方法可以准确鉴别二者。     

米曲霉两株营养缺陷型原生质体的形成和再生的条件实验

采用1%溶壁酶加1%玛瑙螺酶(褐云玛瑙螺消化液的冷冻干粉)的混合酶,自米曲霉(Aspergillus oryzae)的两株营养缺陷型中获得了大量的原生质体,并比较了渗透压稳定剂、温度、菌丝体的培养基成分等因素对原生质体形成和再生的作用。无机盐类稳定剂(NaCl、KCl)获得了高产量的原生质体,而有机类(蔗糖、甘露醇、山梨醇)做为稳定剂不甚理想。对120和720菌株的原生质体在高渗再生培养基上进行再生试验,再生率分别为52%和65%。     

聚半乳糖醛酸酶高产菌的产酶条件研究

通过单因素及正交试验对米曲霉（Aspergillus orza）C491产生聚半乳糖醛酸酶的发酵条件进行了优化。该菌株的摇床发酵滤液以桔子果胶为底物时酶活力可达344．8U／mL。产酶最适培养基组成为：麦芽汁（糖度6％）中添加6％桔皮粉,2％硫酸铵（w/v）。最适培养条件：起始pH4（灭菌前）,30℃,r/min,培养112h。Tween80可以促进C－491产酶。     

Cloning and nucleotide sequence of one of the most highly expressed genes, a pdcA homolog of Aspergillus nidulans, in Aspergillus oryzae

A homolog of Aspergillus nidulans pdcA that is probably one of the most highly expressed in Aspergillus oryzae ATCC 22788 was isolated, as measured by the frequency among randomly selected 324 expressed sequence tags. It has an 1,632 bp open reading frame for a polypeptide of about 60 kDa. Its amino acid sequence revealed 74% identity and 84% similarity to that of A. nidulans pyruvate decarboxylase.     

米曲霉和黑曲霉营养缺陷型的分离及原生质体的制备

米曲霉(Aspergillus oryzae)3042是目前国内酱油生产中广泛使用的菌种,而黑曲霉(Aspergillus niger)3350则是制醋业中广泛使用的菌种。前者具有较高的蛋白酶活性而后者具有较高的淀粉酶活性。在酱油生产中,为了提高原料利用率,改善酱油风味,希望获得一株既有较高的蛋白酶活性同时又具有较高淀粉酶活性的杂交菌株作为     

Structural features of the glycogen branching enzyme encoding genes from aspergilli

A maltose binding protein, p78, was purified to homogeneity from Aspergillus nidulans by a single column chromatography step on cross-linked amylose. The partial amino acid sequence was highly homologous to the glycogen branching enzymes (GBEs) of human and yeast, and p78 did show branching enzyme activity. The genomic gene and its cDNA encoding GBE (p78) were isolated from the A. nidulans genomic and cDNA libraries. Furthermore, a cDNA encoding A. oryzae GBE was entirely sequenced. A. nidulans GBE shared overall and significant amino acid sequence identity with GBEs from A. oryzae (83.9%), Saccharomyces cerevisiae (61.1%) and human (63.0%), and with starch branching enzymes from green plants (55–56%).     

Molecular Cloning,Overexpression, and Purification of a Major Xylanase from Aspergillus oryzae

The gene encoding xylanase G2 (xynG2) was isolated from a genomic library of Aspergillus oryzae KBN616, used for making shoyu koji. The structural part of xynG2 was found to be 767 bp. The nucleotide sequence of cDNA amplified by RT-PCR showed that the open reading frame of xynG2 was interrupted by a single intron which was 71 bp in size and encoded 232 amino acids. Direct N-terminal amino acid sequencing showed that the precursor of XynG2 had a signal peptide of 44 amino acids. The predicted amino acid sequence of XynG2 has strong similarity to other family 11 xylanases from fungi. The xynG2 gene was successfully overexpressed in A. oryzae and the overpexpressed XynG2 was purified. The molecular weight of XynG2 estimated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 21,000. This was almost the same as the molecular weight of 20,047 calculated from the deduced amino acid sequence. The purified XynG2 showed an optimum activity at pH 6.0 and 58°C. It had a Km of 5.1 mg/ml and a Vmax of 123 μmol/min/mg when birch wood xylan was used as a substrate.     

An Endo-(l → 6)-β-d-glucanase of Flavobacterium M64 Hydrolyzing the Octasaccharide Repeating Unit of Succinoglycan to Two Tetrasaccharides

An endo-(l → 6)-β-d-glucanase capable of hydrolyzing octasaccharide to two tetrasaccharides was isolated from cells of Flavobacterium M64. The octasaccharide represents the repeating unit of succinoglycan (SG-D). One tetrasaccharide was composed of d-glucose, succinic acid and pyruvic acid (4:1:1, molar ratio), and the other was composed of d-glucose and d-galactose (3:1, molar ratio). This enzyme hydrolyzed the (l → 6)-β-d-glucosidic linkage adjacent to the (1 → 6)-linked β-d-glucose residue in the octasaccharide repeating unit of succinoglycan and also hydrolyzed the octasaccharide repeating units of similar polysaccharides produced by many strains of Agrobacterium and Rhizobium species.     

Molecular Characterization of a Bacterial Consortium Enriched from an Oilfield that Degrades Phenanthrene

Characterization of functional and phylogenetic genes was carried out on a bacterial consortium, enriched from a water treatment system of an oilfield, that could use phenanthrene as the sole carbon source. The mixed culture degraded 130 mg phenanthrene l⁻¹ in 16 days, which is significantly faster than previously reported pure cultures. The existence of catabolic genes (nahAc, C23O) in the mixed culture was quantitated by most probable number PCR. The plasmid encoding phenanthrene catabolic genes increased relative to the chromosome genes. Heterogeneous bacteria were present according to both PCR denaturing gradient gel electrophoresis and cloning methods, suggesting the possible existence of cooperation between different biochemical PAH-transforming pathways. Revisions requested 15 December 2005; Revisions received 23 January 2006     

Degradation of phenanthrene and anthracene by Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic bacterium

Aims:  The metabolism of phenanthrene and anthracene by a moderate thermophilic Nocardia otitidiscaviarum strain TSH1 was examined.
Methods and Results:  When strain TSH1 was grown in the presence of anthracene, four metabolites were identified as 1,2-dihydroxy-1,2-dihydroanthracene, 3-(2-carboxyvinyl)naphthalene-2-carboxylic acid, 2,3-dihydroxynaphthalene and benzoic acid using gas chromatography-mass spectrometry (GC-MS), reverse phase-high performance liquid chromatography (RP-HPLC) and thin-layer chromatography (TLC). Degradation studies with phenanthrene revealed 2,2'-diphenic acid, phthalic acid, 4-hydroxyphenylacetic acid, o -hydroxyphenylacetic acid, benzoic acid, a phenanthrene dihydrodiol, 4-[1-hydroxy(2-naphthyl)]-2-oxobut-3-enoic acid and 1-hydroxy-2-naphthoic acid (1H2NA), as detectable metabolites.
Conclusions:  Strain TSH1 initiates phenanthrene degradation via dioxygenation at the C-3 and C-4 or at C-9 and C-10 ring positions. Ortho -cleavage of the 9,10-diol leads to formation of 2,2'-diphenic acid. The 3,4-diol ring is cleaved to form 1H2NA which can subsequently be degraded through o -phthalic acid pathway. Benzoate does not fit in the previously published pathways from mesophiles. Anthracene metabolism seems to start with a dioxygenation at the 1 and 2 positions and ortho -cleavage of the resulting diol. The pathway proceeds probably through 2,3-dicarboxynaphthalene and 2,3-dihydroxynaphthalene. Degradation of 2,3-dihydroxynaphthalene to benzoate and transformation of the later to catechol is a possible route for the further degradation of anthracene.
Significance and Impact of the Study:  For the first time, metabolism of phenanthrene and anthracene in a thermophilic Nocardia strain was investigated.     

米曲霉中的一种新病毒与其它真菌病毒的血清型比较

自α-淀粉酶生产菌米曲霉Aspergillus oryzae 3800中找到直径20～24nm的等轴病毒颗粒(AoV),病毒具有典型核蛋白吸收峰,最大E258,最小E242,E260/280=1.36,沉降系数为45S,一个电泳组分,毒粒对氯仿敏感,细胞内含量低,病毒核酸电泳一个组分,地衣酚反应阳性,SDS-不连续聚丙烯酰胺凝胶电泳解离病毒得到分子量为17,800道尔顿的一个主要衣壳多肽。 AoV与小麦全蚀病菌病毒(GgV)的几个衣壳多肽及分子量不同的分离物间有共同的抗原性,而与产黄青霉病毒和同属的黑曲霉病毒不同,这是真菌寄主分类地位较远的病毒间有共同抗原性的不常见例子。