Linhan Bai

Sichuan University, Hua-yang, Sichuan, China

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Publications (13)21.09 Total impact

  • Fangwen Bai · Wei Yan · Shujun Zhang · Dong Yu · Linhan Bai ·
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    ABSTRACT: Signal peptide-deleted lipase, Lipd25A, with transesterification activity from Pseudomonas aeruginosa B10 was overexpressed in Escherichia coli (E. coli) as a fusion with Jatropha curcas oleosin 2 (Jco2). The fusion protein Jco2-Lipd25A which coexpressed with molecular chaperone LipB was named Jco2-Lipd25AB. J. curcas seed oil bodies and Jco2-Lipd25AB were used to prepare reconstructed oil bodies (ROBs) for biodiesel production as immobilized lipase (ROBs-Jco2-Lipd25AB). Results indicated that Jco2-Lipd25AB could be immobilized on ROBs efficiently. The lytic cycle of ROBs was 30 d, meaning that it could be reused three times in series, as evidenced by the stability and reusability analysis. Interestingly, methanol toxicity test suggested that ROBs-Jco2-Lipd25AB presented transesterification activity in a high methanol concentration (300 mmol/L) environment without significant change of transesterification rate. The orthogonal L-25(5(6)) test design showed that the amount of ROBs-Jco2-Lipd25AB and solvent reaction system are the two most important factors in the transesterification reaction. The highest transesterification rate (75.19%) reached under the following optimal conditions: 2 mL ROBs-Jco2-Lipd25AB with a 3/1 ratio of methanol to oil (n/n), water content (%) 1 at 33 degrees C, with shaking at 180 rpm in a petroleum ether reaction system. Due to low cost, easy operation and friendly to environmental, natural oil body mediated immobilized lipase presents great prospects for biodiesel production. (C) 2014 Published by Elsevier Ltd.
    Fuel 07/2014; 128:340–346. DOI:10.1016/j.fuel.2014.03.033 · 3.52 Impact Factor
  • Jingbo Duan · Shaohe Li · Kun Ruan · Linhan Bai ·
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    ABSTRACT: With the genome walking method and nested PCR, enolase gene DsENO 5' upstream regulatory sequence (about 2 000 bp) was cloned from Dunaliella salina, and its sequence analysis was made to investigate the specific function of D. salina during osmotic stress tolerance. The result shows that it includes several conserved sequences related to transcriptional regulation, such as CAAT-box, TATA-box, and it is rich in light, drought and other stress responsive elements. With the real-time fluorescence quantitative PCR method, the DsENO transcription under hyperosmotic, high-temperature and lowtemperature stress were studied to find that it was strongly inhibited by hyperosmotic stress and significantly induced by high-temperature, but slightly induced by low-temperature. Fig 4, Tab 2, Ref 19.
    Chinese Journal of Applied and Environmental Biology 04/2012; 17(2):202-206. DOI:10.3724/SP.J.1145.2011.00202
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    ABSTRACT: The internal transcribed spacer (ITS) region was employed to analyze phylogeny of 20 populations, including the local cultivar “Nanjiang”, belonging to 7 species of Lonicera L. 20 ITS sequences that we obtained range from 614 to 618 bp, and the G+C content was higher than 60% with the average value 63.5%. The sequences of 5.8S nrDNA was highly conservative in both length and component, while ITS2 had more variation than ITS1 in sequence component and length. For the ITS complete sequence, the mutation and information sites were 139 and 117 with the content of 22.38 and 18.84%, respectively. The dendrogram analysed by neighbor-joining method showed that “Nanjiang” and Lonicera similis Hemsl. comprised a same cluster with a higher bootstrap support, indicating “Nanjiang” would be a variation or subspecies of L. similis Hemsl. The results of antibacterial activity test and active compounds identification showed that “Nanjiang” had the best antibacterial activity and the highest yield of chlorogenic acid, the active component of Flos Lonicerae, in the six species of Lonicera L.
    Genetic Resources and Crop Evolution 04/2012; 59(4). DOI:10.1007/s10722-011-9703-8 · 1.46 Impact Factor
  • Xiaomin Chen · Xiaoxue Sang · Shaohe Li · Shujun Zhang · Linhan Bai ·
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    ABSTRACT: Eucommia ulmoides Oliver is a traditional medicinal plant of China, and it is one of the main sources of chlorogenic acid. Chlorogenic acid is an ester of caffeic acid, quinic acid, and a phenolic compound that has antibacterial, antifungal, antioxidant, and antitumor activities. The purpose of this study was to determine whether endophytic fungi isolated from Eucommia ulmoides Oliver had the same ability to produce chlorogenic acid. Primary screening was done by antibacterial and antifungal reactions, and the strain reselection was done with high-performance liquid chromatography (HPLC) to identify the fermentation products of the selected strains. Extracts of the leaf and cortex of Eucommia ulmoides Oliver were also deteted by HPLC, then positive results of HPLC were analyzed by GC-MS and LC-MS. In this study, 29 strains were isolated from Eucommia ulmoides Oliver. Most of them had antibacterial activity, and a few of them had antifungal activity. One ingredient of the B5 extract had a retention time identical to that of authentic chlorogenic acid. With GC-MS, other ingredients, isocoumarin and p-chlorocinnamide, were found. With LC-MS, chlorogenic acid and geniposide related to Eucommia ulmoides Oliver were found. The strain B5 was identified as Sordariomycete sp. Thus, endophytic fungi may produce the bioactive compound chlorogenic acid, as their host plant does, and could be used for the production of chlorogenic acid by fermentation in the future.
    Journal of Industrial Microbiology 05/2010; 37(5):447-54. DOI:10.1007/s10295-010-0690-0 · 2.44 Impact Factor
  • Kuirong WANG · Shujun ZHANG · Shaohe LI · Xiaoxue SANG · Linhan BAI ·
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    ABSTRACT: A moderately halophilic bacterium Halomonas sp. NY-11 was isolated from our laboratory, and its osmotolerance property and mechanism were studied. Strain NY-11 could maximally tolerate 260 g/L NaCl in LB medium and its tolerance to NaCl was over 150 g/L in M63. The absence of chloridion would obviously inhibit the growth of NY-11 under salt and potassium was more suitable to provide intracellular osmotic pressure than lithium and magnesium. NY-11 accumulated potassium, free amino acids and other compatible solutes to equilibrate extracellulary osmotic pressure. The components of the intracellular compatible solutes of NY-11 varied with the changing of NaCl concentrations in medium, while ectoine, which was the most important component, increased with the increasing of NaCl concentration, reaching 71.5 mg/g by dry weight under 120 g/L NaCl. NY-11 could import extracellular ectoine and glycine betaine to improve osmotolerance, and the synthesis of protein was obviously depressed by the increased NaCl concentration in medium.
    Chinese Journal of Applied and Environmental Biology 04/2010; 16(2):256-260. DOI:10.3724/SP.J.1145.2010.00256
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    ABSTRACT: The Dunaliella salina enolase gene (DsENO) had been cloned using Rapid Amplification of cDNA Ends methods. Recombinant D. salina enolase was over-expressed in E. coli BL21 and purified. Native polyacrylamide gel electrophoresis of recombinant enolase indicated that it forms a homo-dimer in the native state. Polyclonal antiserum against purified recombinant D. salina enolase was raised in a rabbit. The enolase activity of DsENO was examined in Kluyveromyces lactis enolase null mutant and DsENO partly complemented the enolase null mutant of K. lactis Rag phenotype. The protein level of D. salina enolase was determined under various conditions. The enolase protein level decreased by more than 50% after between 1.5- and 3-h exposure to hyperosmotic salt stress. This was confirmed by the enolase activity assay. It is suggested that enolase takes part in glycerol synthesis, which can balance the external salt concentration. Under heat-shock treatment, induction of enolase was observed, which suggested that D. salina enolase may contribute to its thermal tolerance.
    European Journal of Phycology 05/2009; 44(2-2):207-214. DOI:10.1080/09670260802573105 · 1.91 Impact Factor
  • Gaopeng Lei · Dairong Qiao · Linhan Bai · Hui Xu · Yi Cao ·
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    ABSTRACT: Mitogen-activated protein kinase (MAPK) is conserved gene family in all eukaryotic cells. MAPKs play an important role in abiotic stress responses. In green algae, few MAPK genes have been cloned, although MAPKs have been extensively studied in yeasts and humans. The microalga Dunaliella is a model for the study of a variety of abiotic stress tolerances. Dunaliella salina exhibits excellent adaptation to the hypersaline environment without a rigid cell wall. The cDNA of MAPK in D. salina was cloned using degenerate oligonucleotide primers in a polymerase chain reaction (PCR) amplification approach and rapid amplification of cDNA ends method. An open reading frame encoding a 53 kDa protein was identified. The deduced amino acid sequence showed high homology with other reported MAPKs. The conserved regions, including TEY activation loop and the common docking domain, were characterized in the deduced amino acid sequence. To our knowledge, we presented the initial full-length sequence of MAPK in D. salina. The quantitative real-time PCR demonstrated DsMPK expression level gradually decreases under the hyperosmotic and low temperature environments. The results provide valuable information about the response of DsMPK at the transcription level.
    Journal of Applied Phycology 02/2008; 20(1):13-17. DOI:10.1007/s10811-007-9175-6 · 2.56 Impact Factor
  • Xue Liang · Dairong Qiao · Min Huang · Xiuli Yi · Linhan Bai · Hui Xu · Liang Wei · Jing Zeng · Yi Cao ·
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    ABSTRACT: There are four LhcII genes of Dunaliella salina have been submitted to the database of GenBank. However, little is known about Lhca genes of this green alga, although this knowledge might be available to study the composition and phylogenesis of Lhc gene family. Recently, one Lhca gene was been cloned from the green alga D. salina by PCR amplification using degenerate primers. This cDNA, designated as DsLhca1, contains an open reading frame encoded a protein of 222 amino acids with a calculated molecular mass of 27.8 kDa. DsLhca1 is predicted to contain three transmembrane domains and a N-terminal chloroplast transit peptide (cTP) with length of 33 amino acids. The genomic sequence of DsLhca1 is composed of five introns. The deduced polypeptide sequence of this gene showed a lower degree of identity (less than 30%) with LHCII proteins from D. salina. But its homology to Lhca proteins of other algae (Volvox carteri Lhca_AF110786) was higher with pairwise identities of up to 67.1%. Phylogenetic analysis indicated that DsLhcal protein cannot be assigned to any types of Lhca proteins in higher plants or in Chlamydomonas reinhardtii.
    DNA Sequence 08/2007; 19(2):137-45. DOI:10.1080/10425170701447614 · 0.41 Impact Factor
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    ABSTRACT: The mitochondrial FAD-dependent glycerol-3-phosphate dehydrogenase (FAD-GPDH), recently reported in plants, has been detailed in yeast and animal systems. It oxidizes glycerol-3-phosphate (G-3-P) to dihydroxyacetone phosphate (DHAP) on the outer surface of mitochondrial inner membrane. A cDNA encoding the Dunaliella salina mitochondrial glycerol-3-phosphate dehydrogenase (DsFAD-GPDH) has been cloned and sequenced. The full length cDNA is 2791 bp, with an open reading frame (ORF) encoding 650 predicted amino acids, which show strong homology to reported FAD-GPDHs and have an apparent mitochondrial targeting sequence in the N-terminal. The sequence has been submitted to the GenBank database under Accession No. DQ916107. Results of Real-Time Quantitative PCR and enzymatic assays show that expression of DsFAD-GPDH is enhanced at first by salt treatment, and repressed by oxygen deficiency and cold stress.
    Journal of Basic Microbiology 06/2007; 47(3):266-74. DOI:10.1002/jobm.200610263 · 1.82 Impact Factor
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    Yi Yi · Dairong Qiao · Linhan Bai · Hui Xu · Ya Li · Xiaolin Wang · Yi Cao ·
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    ABSTRACT: 5-enolpyruvylshikimate-3-phosphate synthase (EPSP synthase, EC is the sixth enzyme in the shikimate pathway which is essential for the synthesis of aromatic amino acids and many secondary metabolites. The enzyme is widely involved in glyphosate tolerant transgenic plants because it is the primary target of the nonselective herbicide glyphosate. In this study, the Dunaliella salina EPSP synthase gene was cloned by RT-PCR approach. It contains an open reading frame encoding a protein of 514 amino acids with a calculated molecular weight of 54.6 KDa. The derived amino acid sequence showed high homology with other EPSP synthases. The Dunaliella salina EPSP synthase gene was expressed in Escherichia coli and the recombinant EPSP synthase were identified by functional complementation assay.
    The Journal of Microbiology 05/2007; 45(2):153-7. · 1.44 Impact Factor
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    ABSTRACT: A cDNA encoding a nicotinamide adenine dinucleotide (NAD+) -dependent glycerol 3-phosphate dehydrogenase (GPDH) has been cloned by rapid amplification of cDNA ends from Dunaliella salina. The cDNA is 3032 base pairs long with an open reading frame encoding a polypeptide of 701 amino acids. The polypeptide shows high homology with published NAD+ -dependent GPDHs and has at its N-terminal a chloroplast targeting sequence. RNA gel blot analysis was performed to study GPDH gene expression under different conditions, and changes of the glycerol content were monitored. The results indicate that the cDNA may encode an osmoregulated isoform primarily involved in glycerol synthesis. The 701-amino-acid polypeptide is about 300 amino acids longer than previously reported plant NAD+ -dependent GPDHs. This 300-amino-acid fragment has a phosphoserine phosphatase domain. We suggest that the phosphoserine phosphatase domain functions as glycerol 3-phosphatase and that, consequently, NAD+ -dependent GPDH from D. salina can catalyze the step from dihydroxyacetone phosphate to glycerol directly. This is unique and a possible explanation for the fast glycerol synthesis found in D. salina.
    Journal of Plant Physiology 03/2007; 164(2):214-20. DOI:10.1016/j.jplph.2006.04.004 · 2.56 Impact Factor
  • Liang Wei · Yi Cao · Linhan Bai · Xue Liang · Tingting Deng · Jing Li · Dairong Qiao ·
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    ABSTRACT: Genes encoding proteins of the major light-harvesting complex of photosystem II (LHCII) in higher plants are well studied. However, little is known about the corresponding genes in the green alga Dunaliella salina, although this knowledge might provide valuable information about the respective roles of each LHCII protein at the molecular level under extreme environmental conditions. Here, we describe an additional LhcII gene from D. salina. An LhcII cDNA cloned by screening a D. salina cDNA library contains an open reading frame encoding a protein of 261 amino acids with a calculated molecular mass of 27.8kDa. The deduced amino acid sequence shows high homology with other LHCII proteins. Genomic DNA—obtained by PCR using a specific primer set corresponding to the 5′ and 3′ untranslated regions—was used to determine the intron-exon structure. Short-term changes in mRNA levels after a shift from low-light to high-light or dark conditions were analyzed by real-time quantitative PCR, and indicated that this gene expresses different mRNA levels under different light conditions.
    Journal of Applied Phycology 02/2007; 19(1):89-94. DOI:10.1007/s10811-006-9116-9 · 2.56 Impact Factor
  • Liang Wei · Yi Cao · Xue Liang · Yi Liu · Tingting Deng · Linhan Bai · Dairong Qiao ·
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    ABSTRACT: Dunaliella salina is a useful model for studying the respective roles of each LHCII protein at the molecular level in extreme environmental conditions. However, information about the LhcII genes in D. salina is very limited. In order to identify more LhcII genes in D. salina, two additional LhcII cDNAs were obtained by screening a cDNA library. The genomic DNA was amplified by PCR using a specific primer set corresponding to the 5' and 3' untranslated regions of each transcript. The untranslated regions of the two additional genes are obviously different from each other; therefore they are two genes. Each gene contains an open reading frame for a protein of 253 amino acids. The two deduced proteins in D. salina are 99% identical at the amino acid sequence level to the previously reported LHCII protein in the same genus D. tertiolecta. Unrooted phylogenetic tree showed that types of LHCII proteins in D. salina did not correspond to any types in C. reinhardtii.
    DNA Sequence 11/2006; 17(5):370-7. DOI:10.1080/10425170600752775 · 0.41 Impact Factor