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, Volume 16 Issue 4 Previous Issue    Next Issue
Articles
Synthetic promoters consisting of defined cis-acting elements link multiple signaling pathways to probenazole-inducible system
Zheng Zhu, Jiong Gao, Jin-xiao Yang, Xiao-yan Wang, Guo-dong Ren, Yu-long Ding, Ben-ke Kuai
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015, 16(4): 253-263.   https://doi.org/10.1631/jzus.B1400203
Abstract   PDF (0KB)
Probenazole (3-allyloxy-1,2-benzisothiazole-1,1-dioxide, PBZ), the active component of Oryzemate, could induce systemic acquired resistance (SAR) in plants through the induction of salicylic acid (SA) biosynthesis. As a widely used chemical inducer, PBZ is a good prospect for establishing a new chemical-inducible system. We first designed artificially synthetic promoters with tandem copies of a single type of cis-element (SARE, JERE, GCC, GST1, HSRE, and W-box) that could mediate the expression of the β-glucuronidase (GUS) reporter gene in plants upon PBZ treatment. Then we combined different types of elements in order to improve inducibility in the PBZ-inducible system. On the other hand, we were surprised to find that the cis-elements, which are responsive to jasmonic acid (JA) and ethylene, also responded to PBZ, implying that SA, JA, and ethylene pathways also would play important roles in PBZ’s action. Further analysis demonstrated that PBZ also induced early events of innate immunity via a signaling pathway in which Ca2+ influx and mitogen-activated protein kinase (MAPK) activity were involved. We constructed synthesized artificial promoters to establish a PBZ chemical-inducible system, and preliminarily explored SA, JA, ethylene, calcium, and MAPK signaling pathways via PBZ-inducible system, which could provide an insight for in-depth study.
Alternaria toxin-induced resistance in rose plants against rose aphid (Macrosiphum rosivorum): effect of tenuazonic acid
Fa-zhong Yang, Bin Yang, Bei-bei Li, Chun Xiao
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015, 16(4): 264-274.   https://doi.org/10.1631/jzus.B1400151
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Many different types of toxins are produced by the fungus, Alternaria alternata (Fr.) Keissler. Little is known, however, regarding the influence of these toxins on insects. In this study, we investigated the toxin-induced inhibitory effects of the toxin produced by A. alternata on the rose aphid, Macrosiphum rosivorum, when the toxin was applied to leaves of the rose, Rosa chinensis. The results demonstrated that the purified crude toxin was non-harmful to rose plants and rose aphids, but had an intensive inhibitory effect on the multiplication of aphids. The inhibitory index against rose aphids reached 87.99% when rose plants were sprayed with the toxin solution at a low concentration. Further results from bioassays with aphids and high performance liquid chromatography (HPLC) analyses demonstrated that tenuazonic acid (TeA) was one of the most important resistance-related active components in the crude toxin. The content of TeA was 0.1199% in the crude toxin under the HPLC method. Similar to the crude toxin, the inhibitory index of pure TeA reached 83.60% 15 d after the rose plants were sprayed with pure TeA solution at the lower concentration of 0.060 μg/ml, while the contents of residual TeA on the surface and in the inner portion of the rose plants were only 0.04 and 0.00 ng/g fresh weight of TeA-treated rose twigs, respectively, 7 d after the treatment. Our results show that TeA, an active component in the A. alternata toxin, can induce the indirect plant-mediated responses in rose plants to intensively enhance the plant’s resistances against rose aphids, and the results are very helpful to understand the plant-mediated interaction between fungi and insects on their shared host plants.
Evaluation of yeasts from Tibetan fermented products as agents for biocontrol of blue mold of Nashi pear fruits
Hao Hu, Yang Xu, Huang-ping Lu, Rui Xiao, Xiao-dong Zheng, Ting Yu
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015, 16(4): 275-285.   https://doi.org/10.1631/jzus.B1400162
Abstract   PDF (0KB)
A total of 20 strains of yeast isolated from Tibetan fermented products were screened for antagonism against blue mold of pear caused by Penicillium expansum. Six isolates that inhibited incidence of postharvest decay by 35% or more were selected for further screening. Among them, the most effective was Rhodotorula mucilaginosa. The results showed that washed cell suspensions of R. mucilaginosa yielded better antagonistic efficacy than unwashed cell-culture mixtures, cell-free culture filtrates, and autoclaved cell cultures. Biocontrol activity improved with increasing concentrations of incubated cells. The best concentration was 1×108 cells/ml, at which the incidence of decay was only 16.7% after 6 d of incubation. The germination of conidia of P. expansum in vitro was significantly inhibited by both washed cell-suspensions and unwashed cell-culture mixtures. Rapid colonization by yeast at different concentrations showed a relationship between yeast-cell concentration and biocontrol activity. Although the titratable acidity of pear fruits increased after treatment, R. mucilaginosa did not affect the total soluble solids or ascorbic acid content. This is the first study to report that the yeast R. mucilaginosa from Tibet Autonomous Region of China may have potential as an antagonist to control the postharvest decay of pear fruits.
Mutation breeding of high 4-androstene-3,17-dione-producing Mycobacterium neoaurum ZADF-4 by atmospheric and room temperature plasma treatment
Chao Liu, Xian Zhang, Zhi-ming Rao, Ming-long Shao, Le-le Zhang, Dan Wu, Zheng-hong Xu, Hui Li
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015, 16(4): 286-295.   https://doi.org/10.1631/jzus.B1400274
Abstract   PDF (0KB)
Steroid medication is used extensively in clinical applications and comprises a large and vital part of the pharmaceutical industry. However, the difficulty of separating 4-androstene-3,17-dione (AD) from 1,4-androstadiene-3,17-dione (ADD) restricts the application of the microbial transformation of phytosterols in the industry. A novel atmospheric and room temperature plasma (ARTP) treatment, which employs helium as the working gas, was used to generate Mycobacterium neoaurum mutants producing large amounts of AD. After treatment of cultures with ARTP, four mutants were selected using a novel screening method with a color assay. Among the mutants, M. neoaurum ZADF-4 was considered the best candidate for industrial application. When the fermentation medium contained 15 g/L phytosterols and was cultivated on a rotary shaker at 160 r/min at 30 °C for 7 d, (6.28±0.11) g/L of AD and (0.82±0.05) g/L of ADD were produced by the ZADF-4 mutant, compared with (4.83±0.13) g/L of AD and (2.34±0.06) g/L of ADD by the original strain, M. neoaurum ZAD. Compared with ZAD, the molar yield of AD increased from 48.3% to 60.3% in the ZADF-4 mutant. This result indicates that ZADF-4 may have potential for industrial production of AD.
Expression profiles of miRNAs in Gossypium raimondii
Jun Ma, Teng-long Guo, Qing-lian Wang, Kun-bo Wang, Run-run Sun, Bao-hong Zhang
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015, 16(4): 296-303.   https://doi.org/10.1631/jzus.B1400277
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miRNAs are a class of conserved, small, endogenous, and non-protein-coding RNA molecules with 20–24 nucleotides (nt) in length that function as post-transcriptional modulators of gene expression in eukaryotic cells. Functional studies have demonstrated that plant miRNAs are involved in the regulation of a wide range of plant developmental processes. To date, however, no research has been carried out to study the expression profiles of miRNAs in Gossypium raimondii, a model cotton species. We selected 16 miRNAs to profile their tissue-specific expression patterns in G. raimondii four different tissues, and these miRNAs are reported to play important roles in plant growth and development. Our results showed that the expression levels of these miRNAs varied significantly from one to another in a tissue-dependent manner. Eight miRNAs, including miR-159, miR-162, miR-164, miR-172, miR-390, miR-395, miR-397, and miR-398, exhibited exclusively high expression levels in flower buds, suggesting that these miRNAs may play significant roles in floral development. The expression level of miR-164 was relatively high in shoots beside flower buds, implying that the function of miR-164 is not only limited to floral development but it may also play an important role in shoot development. Certain miRNAs such as miR-166 and miR-160 were extremely highly expressed in all of the four tissues tested compared with other miRNAs investigated, suggesting that they may play regulatory roles at multiple development stages. This study will contribute to future studies on the functional characterization of miRNAs in cotton.
Cassava stillage and its anaerobic fermentation liquid as external carbon sources in biological nutrient removal
Fan Bu, Xiang Hu, Li Xie, Qi Zhou
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015, 16(4): 304-316.   https://doi.org/10.1631/jzus.B1400106
Abstract   PDF (0KB)
The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic-anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-β-hydroxyalkanoates (PHAs), and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating organisms (PAOs) and denitrifying phosphorus accumulating organisms (DPAOs) demonstrated that the proportion of DPAOs to PAOs reached 62.6% (Day 86) and 61.8% (Day 65) when using cassava stillage and its anaerobic fermentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates (NURs) of the cassava by-products were in the range of 5.49–5.99 g N/(kg MLVSS⋅h) (MLVSS is mixed liquor volatile suspended solids) and 6.63–6.81 g N/(kg MLVSS⋅h), respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes.
Effect of culturing conditions on the expression of key enzymes in the proteolytic system of Lactobacillus bulgaricus
Jun-cai Hou, Fei Liu, Da-xi Ren, Wei-wei Han, Yue-ou Du
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015, 16(4): 317-326.   https://doi.org/10.1631/jzus.B1400230
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The proteolytic system of Lactobacillus bulgaricus breaks down milk proteins into peptides and amino acids, which are essential for the growth of the bacteria. The aim of this study was to determine the expressions of seven key genes in the proteolytic system under different culturing conditions (different phases, initial pH values, temperatures, and nitrogen sources) using real-time polymerase chain reaction (RT-PCR). The transcriptions of the seven genes were reduced by 30-fold on average in the stationary phase compared with the exponential growth phase. The transcriptions of the seven genes were reduced by 62.5-, 15.0-, and 59.0-fold in the strains KLDS 08006, KLDS 08007, and KLDS 08012, respectively, indicating that the expressions of the seven genes were significantly different among strains. In addition, the expressions of the seven genes were repressed in the MRS medium containing casein peptone. The effect of peptone supply on PepX transcription was the weakest compared with the other six genes, and the impact on OppD transcription was the strongest. Moreover, the expressions of the seven genes were significantly different among different strains (P<0.05). All these results indicated that the culturing conditions affected the expression of the proteolytic system genes in Lactobacillus bulgaricus at the transcription level.
Correspondence
Transcatheter aortic valve implantation for Chinese patients with bicuspid aortic valve
Yu-guo Weng
Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015, 16(4): 327-328.   https://doi.org/10.1631/jzus.B1500063
Abstract   PDF (0KB)
The recent paper by the corresponding author Jian-an WANG and his team entitled "Evaluation of the safety and efficacy of transcatheter aortic valve implantation in patients with a severe stenotic bicus-pid aortic valve in a Chinese population" (Liu et al., 2015), published in the Journal of Zhejiang University- SCIENCE B (Biomedicine & Biotechnology), is very impressive. They evaluated the safety and efficacy of transcatheter aortic valve implantation (TAVI) in patients with bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) for the first time in the Chinese population. This paper reported 40 cases of clinical experience of TAVI, and first explicitly put forward the indication of stenosis in the BAV. The early and mid-term outcomes between BAV and TAV groups are almost the same, and the high procedural success rate and low complication rate of their study are encouraging.
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