Role of the Phenylalanine-Hydroxylating System in Aromatic Substance Degradation and Lipid Metabolism in the Oleaginous Fungus Mortierella alpina

Mortierella alpina is a filamentous fungus commonly found in soil that is able to produce lipids in the form of triacylglycerols that account for up to 50% of its dry weight. Analysis of the M. alpina genome suggests that there is a phenylalanine-hydroxylating system for the catabolism of phenylalanine, which has never been found in fungi before. We characterized the phenylalanine-hydroxylating system in M. alpina to explore its role in phenylalanine metabolism and its relationship to lipid biosynthesis. Significant changes were found in the profile of fatty acids in M. alpina grown on medium containing an inhibitor of the phenylalanine-hydroxylating system compared to M. alpina grown on medium without inhibitor. Genes encoding enzymes involved in the phenylalanine-hydroxylating system (phenylalanine hydroxylase [PAH], pterin-4α-carbinolamine dehydratase, and dihydropteridine reductase) were expressed heterologously in Escherichia coli, and the resulting proteins were purified to homogeneity. Their enzymatic activity was investigated by high-performance liquid chromatography (HPLC) or visible (Vis)-UV spectroscopy. Two functional PAH enzymes were observed, encoded by distinct gene copies. A novel role for tetrahydrobiopterin in fungi as a cofactor for PAH, which is similar to its function in higher life forms, is suggested. This study establishes a novel scheme for the fungal degradation of an aromatic substance (phenylalanine) and suggests that the phenylalanine-hydroxylating system is functionally significant in lipid metabolism.     

Endophytes isolated from Panax notoginseng converted ginsenosides

Endophytes may participate in the conversion of metabolites within medicinal plants, influencing the efficacy of host. However, the distribution of endophytes within medicinal plants P. notoginseng and how it contributes to the conversion of saponins are not well understood. Here, we determined the distribution of saponins and endophytes within P. notoginseng compartments and further confirm the saponin conversion by endophytes. We found metabolites showed compartment specificity within P. notoginseng. Potential saponin biomarkers, such as Rb1, Rg1, Re, Rc and Rd, were obtained. Endophytic diversity, composition and co-occurrence networks also showed compartment specificity, and bacterial alpha diversity values were highest in root compartment, consistently decreased in the stem and leaf compartments, whereas those of fungi showed the opposite trend. Potential bacterial biomarkers, such as Rhizobium, Bacillus, Pseudomonas, Enterobacter, Klebsiella, Pantoea and fungal biomarkers Phoma, Epicoccum, Xylariales, were also obtained. Endophytes related to saponin contents were found by Spearman correlation analysis, and further verification experiments showed that Enterobacter chengduensis could convert ginsenoside Rg1 to F1 at a rate of 13.24%; Trichoderma koningii could convert ginsenoside Rb1 to Rd at a rate of 40.00% and to Rg3 at a rate of 32.31%; Penicillium chermesinum could convert ginsenoside Rb1 to Rd at a rate of 74.24%.     

Cervical Spondylotic Myelopathy Caused by Single-Level Vertebral Spontaneous Fusion

Purpose

To evaluate the clinical features, imaging characteristics, surgical options, and clinical outcomes of patients with Cervical spondylotic myelopathy (CSM) caused by single-level vertebral spontaneous fusion (SLVSF).

Methods

Sixteen consecutive patients with SLVSF who underwent anterior surgery were included in this study and 38 patients with CSM caused by spinal degeneration were enrolled as a control group. Demographic features, clinical presentations, imaging characteristics, surgery strategy, Nurick grade, Japanese Orthopedic Association (JOA) score, neck disability index (NDI), and complications were evaluated.

Results

There were significant differences between the two groups in the mean age and the average duration of neck pain. There was no significant difference between the two groups in length of cervical spine. In the SLVSF group, 13 patients had upper segment translational instability and none had rotational instability. Pre- and postoperative Nurick grades were 2.94±0.77 and 2.19±0.54 in the SLVSF group, and 2.97±0.72 and 2.16±0.64 in the control group. Pre- and postoperative JOA scores were 9.25±2.02 and 11.69±1.62 in the SLVSF group, and 9.87±2.58 and 12.53±2.69 in the control group. Pre- and postoperative NDI values were 28.5±7.75 and 15.56±5.51 in the SLVSF group, and 16±6.13 and 11.29±4.58 in the control group.

Conclusions

Patients with SLVSF have necks of normal lengths, which can be used to distinguish this disorder from Klippel-Feil syndrome. There are three main features of SLVSF: (1) hypoplasia at both of the spontaneously fused vertebral bodies; (2) a major pathological feature of translational instability of the upper vertebra to the fused level; and (3) severe neck pain. Anterior surgery has a good therapeutic effect for patients with cervical SLVSF.     

Assembly of rhizosphere microbial communities in Artemisia annua: recruitment of plant growth‐promoting microorganisms and inter‐kingdom interactions between bacteria and fungi

Plant and Soil - Plant roots assemble unique microbial communities in rhizosphere, which are critical for plant adapting to natural environment. Given the pivotal importance of plant-microbe...     

发菜耐旱相关蛋白NXL-01的基因克隆与表达分析

在发菜耐旱差异蛋白质组学研究中,发现假定蛋白(Hypothetical protein NXL-01)在干旱胁迫条件下表达量逐渐增加。根据已知氨基酸序列设计简并引物克隆NXL-01基因,长度为327bp(GenBank登录号为HM854288)。生物信息学分析表明,该基因具有较高保守性,蛋白质二级结构主要由α螺旋和随机卷曲构成,是亲水性的膜外蛋白,有5个Ser磷酸化位点,1个Thr磷酸化位点。将NXL-01基因在大肠杆菌中表达,获得预期大小的重组蛋白(12.4kD)。RT-PCR分析表明,NXL-01mRNA在干旱胁迫条件下表达量逐渐增加,与NXL-01蛋白的表达趋势一致。     

Development of bioreactor systems with functional bio-carrier modified by disperse turquoise blue S-GL for disperse scarlet S-BWFL decolorization

The effect of redox mediator has been studied in details in the bio-decolorization processes, but there are little literatures about bioreactor systems with functional bio-carrier modified by redox mediator. Two different bioreactor configurations (bioreactor R1 with functional bio-carrier modified by disperse turquoise blue S-GL (as redox mediator) and bioreactor R2 with non-modified bio-carrier) were designed and tested for disperse scarlet S-BWFL decolorization by Halomonas sp. GYW (EF188281) in this study. Influencing factors such as co-substrate, temperature and pH were optimized through batch experiments. Compared to bioreactor R2, bioreactor R1 exhibited good decolorization efficiency and performance ability for the disperse scarlet S-BWFL decolorization, which showed higher decolorization efficiency (over 96% color removal with 0.8 g L(-1) dye concentration) and less hydraulic retention time to attain the same decolorization efficiency. The combinational technology of redox mediator and bio-carrier was a new bio-treatment concept and a great improvement for the application of redox mediator.     

抗甲霜灵辣椒疫霉菌的环境适合度

摘要:【目的】研究抗甲霜灵辣椒疫霉菌的环境适合度,对于评估甲霜灵防治辣椒疫霉的抗药性风险具有重要意义。【方法】以室内药剂驯化的抗甲霜灵辣椒疫霉菌株Pc2-3为研究对象,分析比较其与原始敏感菌株Pc2的主要生物学特性、生长竞争力、致病力及土壤适合度等环境适合度指标。【结果】Pc2-3孢子囊产生量(3 d后)、孢子囊释放率(24 h后)和游动孢子萌发率(8 h后)分别是Pc2的0.44、0.09和0.54倍。Pc2-3可生长温度和pH范围及最适生长温度与Pc2基本一致,但菌丝生长速率低于Pc2。竞争力测定显示,在胡萝卜(CA)平板培养条件下,Pc2-3生长极显著弱于Pc2。盆栽致病试验显示,Pc2-3对辣椒植株的致病率为14.3%,明显低于Pc2(88.6%)。两者等量混合后接种,辣椒植株的发病率为75.7%,接近单独接种Pc2时的发病率,且所有病株分离出的辣椒疫霉菌均为甲霜灵敏感型。分别将Pc2-3和Pc2游动孢子加入自然土壤培养20 d后,实时定量PCR检测显示Pc2-3数量是Pc2的0.28倍,当土壤中含有300 mg/kg干土的甲霜灵,则前者为后者的0.42倍。此外,2个菌株最适存活土壤温度和湿度基本一致,当土壤温度和湿度利于辣椒疫霉存活时,Pc2-3土壤适合度显著低于Pc2,不利于辣椒疫霉存活时,Pc2-3土壤适合度略低于Pc2。【结论】抗甲霜灵菌株Pc2-3环境适合度弱于原始敏感菌株Pc2。