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Tan H.,Sichuan Agricultural University | Zhang Z.,Microbiology Institute of Shaanxi | Hu Y.,Sichuan Agricultural University | Wu L.,Sichuan Agricultural University | And 8 more authors.
Food Control | Year: 2015

Zearalenone (ZEA) is a nonsteroidal estrogenic mycotoxin produced by various Fusarium species and causes hyperestrogenism and related toxicosis of farm animals and humans. The present study aimed to isolate and identify ZEA-resistant bacteria from rumen in order to develop some strategies for detoxifying ZEA-contaminated food and feed. A bacterial strain was isolated from the rumen contents for its ability to utilize ZEA as the sole carbon and energy source. The isolate was an aerobic, Gram-negative, rod-shaped bacterium with single polar flagellum and was named Pseudomonas otitidis TH-N1 based on the morphology and 16S rRNA gene sequence. Meanwhile, the present study investigated that how various influence factors of P.otitidis TH-N1 could remove ZEA from a liquid medium. The optimal temperature, pH value, and concentrations of bacteria for the biodegradation of ZEA were 37°C, 4.5, and 109cfu/ml, respectively. These results suggest that P.otitidis TH-N1 is a new bacterium found from the rumen and exhibited remarkable degradation activity of ZEA. It is probably a new bacterial resource to detoxify ZEA from ZEA-contaminated food and feed. © 2014 Elsevier Ltd. Source

Ma X.,Xian University of Architecture and Technology | Nie M.,Xian University of Architecture and Technology | Lu J.,Xian University of Architecture and Technology | Nie H.,Xian University of Architecture and Technology | And 3 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2014

The effects of biosurfactant rhamnolipid on the surface properties of Pseudomonas aeruginosa NY3 and its degradation efficiency of hydrocarbons were studied. The results showed that rhamnolipid could increase the crude oil bioavailability. Compared with the rhamnolipid-free conditions, when the concentration of crude oil was 1000 mg·L-1, the net accumulated biomass of NY3 strain cells increased by 8.60 times at 24 h with the existence of 100 mg·L-1 rhamnolipid. Faster growth resulted in quicker declining of the pH values of the culture. The degradation rates of the alkanes ranging from hexacosane to tritriacontane in the crude oil were promoted to about 60% by the rhamnolipid. The hydrophobicity of the NY3 cells (OD400nm=1.68±0.08) harvested from LB medium enhanced 32% after 1.5 h interaction with rhamnolipid (100 mg·L-1) and that of the cells harvested from minimal medium with hexadecane as the sole carbon source enhanced only 6%. Cells harvested from LB medium accumulated and were intaken 1.10 nmol·mg-1 dry cell more hexadecane with the assistance of rhamnolipid. The results indicated that rhamnolipid could accelerate mass transfer rate of hydrophobic organic compounds onto cells. The analysis of FT-IR suggested that the ratio of the hydrophilic functional groups contained in cells harvested from both medium reduced obviously after interaction with rhamnolipid. We may therefore conclude that rhamnolipid could enhance the hydrophobicity of NY3 cell surfaces, accelerate mass transfer rate of hydrocarbons, and promote the degradation rate of hydrocarbons by strain NY3. Source

Huang J.-X.,Northwest University, China | Zhang J.,Northwest University, China | Zhang X.-R.,Shaanxi Normal University | Zhang K.,Microbiology Institute of Shaanxi | And 2 more authors.
Pharmaceutical Biology | Year: 2014

Results: Among six endophytic fungi isolated from the rhizomes of S. hexandrum, one strain was able to produce kaempferol. Another strain, named TW5, was able to produce both kaempferol and podophyllotoxin simultaneously according to the TLC, HPLC, and NMR results. The podophyllotoxin yield of TW5 was calculated to be 49.3 μg/g of mycelial dry weight after 7-d fermentation. Strain TW5 was identified morphologically and phylogenetically to be Mucor fragilis Fresen. (Mucoraceae). These results suggest that the podophyllotoxin-synthesizing ability is obtained by uptaking genes involved in the podophyllotoxin synthesis from the host plant into endophytic fungal genomes.Conclusion: Our results showed, for the first time, that the endophytic fungus M. fragilis is able to produce simultaneously the same two bioactive metabolites, podophyllotoxin and kaempferol, as its host plant. Furthermore, the relatively high podophyllotoxin yield obtained may improve the industrial production of podophyllotoxin, which may help protect this endangered plant. © 2014 Informa Healthcare USA.Objective: The aim of this study was to isolate podophyllotoxin-producing endophytic fungi from Sinopodophyllum hexandrum (Royle) Ying (1979) (Berberidaceae) plants of the Taibai Mountains of China in order to obtain bioactive compounds.Materials and methods: The strains producing kaempferol and podophyllotoxin were screened by thin-layer chromatography (TLC) analysis. The presence of kaempferol and podophyllotoxin in extracts of these strains was further confirmed by high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR) analyses.Context: Podophyllotoxin, a pharmaceutically important bioactive compound of Podophyllum sps. (Berberidaceae), is in great demand worldwide as an anticancer and antivirus drug precursor. However, the source of podophyllotoxin is very limited due to the endangered status of the Podophyllum plant. Source

Gao L.,Microbiology Institute of Shaanxi | Zhang Y.,CAS Institute of Biophysics | Wang Y.,Microbiology Institute of Shaanxi | Qiao X.,CAS Institute of Biophysics | And 4 more authors.
Redox Biology | Year: 2016

Pyocyanin (PCN), a virulence factor synthesized by Pseudomonas aeruginosa, plays an important role during clinical infections. There is no study of the effect of nitric oxide (NO) on PCN biosynthesis. Here, the effect of NO on PCN levels in Pseudomonas aeruginosa strain PAO1, a common reference strain, was tested. The results showed that the NO donor sodium nitroprusside (SNP) can significantly reduce PCN levels (82.5% reduction at 60 μM SNP). Furthermore, the effect of endogenous NO on PCN was tested by constructing PAO1 nor (NO reductase gene) knockout mutants. Compared to the wild-type strain, the δnor strain had a lower PCN (86% reduction in δnor). To examine whether the results were universal with other P. aeruginosa strains, we collected 4 clinical strains from a hospital, tested their PCN levels after SNP treatment, and obtained similar results, i.e., PCN biosynthesis was inhibited by NO. These results suggest that NO treatment may be a new strategy to inhibit PCN biosynthesis and could provide novel insights into eliminating P. aeruginosa virulence as a clinical goal. © 2016 . Source

Dai J.K.,Shaanxi Academy of science | Dai J.K.,Northwest University, China | Li Y.,Microbiology Institute of Shaanxi | Zhuang H.H.,Northwest University, China | And 5 more authors.
Advanced Materials Research | Year: 2014

An appropriate ultrasonication of collecting foreign recombinant protein (human-adiponectin) from yeast was established. Regarded the bioactivity of foreign recombinant protein tested by Western Blotting analysis as parameter, a L9(33) orthogonal array design based on a series of single-factor experiments was employed to optimize conditions for ultrasonic disruption. The results showed that the ultrasonic power of 450 W, duration time on 25 min and operation interval(work time: intermittent time) of 10:10 (s/s) were optimal process with the highest protein bioactivity, and meanwhile, the cell breaking rate was (67.8±2.1) %. © (2014) Trans Tech Publications, Switzerland. Source

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