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  • 1. Ali, M. A. E.
    et al.
    Abdel-Fatah, O. M.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Elshafei, A. M.
    Antimicrobial potential of Saccharomyces boulardii extracts and fractions2012Ingår i: Journal of Applied Sciences Research, ISSN 1816-157X, E-ISSN 1819-544X, Vol. 8, nr 8, s. 4537-4543Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Different extracts of viable therapeutic Saccharomyces boulardii cells were evaluated for their antimicrobial activities against Escherichia coli and Candida albicans. Water, methanol, isopropanol, n-butanol and ethanol were used as solvents for extraction. Ethanol-extract exhibited the highest antimicrobial activity towards both strains, followed by water-extract. No antimicrobial activity could be detected on testing methanol-extract towards both strains. Ethanol- and water-extracts, cells remaining after water and ethanol extraction and broth were also tested for their antimicrobial activities against Gram-positive, Gram-negative, non-filamentous and filamentous fungi and showed considerable amounts of antimicrobial activities. Ethanol extracts exhibited the highest antimicrobial activity against all the tested strains, was then fractionated on a Sephadex G-100 column and the obtained fractions were examined using the agar-well diffusion method against Staphylococcus aureus, E.coli, C. albicans and Aspergillus niger. Results obtained indicate the presence of different scattered active fractions with different potencies against the four tested microorganisms. A large scale fermentation process was conducted using a BioFlo benchtop-15L Fermentor/ Bioreactor and the products were evaluated for their antimicrobial activities.

  • 2. Batista-Viera, F
    et al.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Carlsson, J
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Affinity chromatography2011Ingår i: Protein Purification, Principles, High Resolution Methods and Applications / [ed] J-C Janson, John Wiley & Sons Inc. , 2011, 3, s. 221-258Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 3.
    Caldwell, Karin D.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    The Origin of Sepahdex2006Ingår i: GIT Laboratory Journal: Europe, Vol. 10, nr 5, s. 18-20Artikel i tidskrift (Övrigt vetenskapligt)
  • 4. Ersson, B
    et al.
    Rydén, L
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Uppsala centrum för hållbar utveckling, CSD Uppsala.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Introduction to protein purification2011Ingår i: Protein Purification, Principles, High Resolution Methods and Applications / [ed] J-C Janson, John Wiley & Sons Inc. , 2011, 3, s. 3-22Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 5. Gu, M.
    et al.
    Su, Z. -G.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    One-step purification of resveratrol and polydatin from Polygonum cuspidatum (Sieb. & Zucc.) by isocratic hydrogen bond adsorption chromatography on cross-linked 12% agarose2006Ingår i: Chromatographia, ISSN 0009-5893, E-ISSN 1612-1112, Vol. 64, nr 11-12, s. 701-704Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Resveratrol and polydatin (piceid), the major active components of the traditional Chinese medicinal herb Polygonum cuspidatum (Sieb. & Zucc.), have been separated and purified from crude root extracts in one step by isocratic hydrogen bond adsorption chromatography on cross-linked 12% agarose (Superose™ 12 HR 10/30). Separation was achieved by step-wise elution with mobile phases composed of mixtures of ethanol and acetic acid: 0–75 mL, 10% ethanol, 10% acetic acid; 75–150 mL, 20% ethanol, 20% acetic acid; 150–250 mL, 30% ethanol, 30% acetic acid. At a sample load of 40 mg crude extract dissolved in 0.5 mL mobile phase (corresponding to a load of 1.7 mg mL−1 gel) a resveratrol purity of about 96% with a recovery of 61% was obtained by proper peak cutting.

  • 6. Gu, M.
    et al.
    Su, Z.-G.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik.
    The Separation of Polyphenols by Isocratic Hydrogen Bond Adsorption Chromatography on a Cross-Linked 12% Agarose Gel2006Ingår i: Chromatographia, ISSN 0009-5893, E-ISSN 1612-1112, Vol. 64, nr 5-6, s. 247-253Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The highly cross-linked 12% agarose gel, Superose™ 12 HR 10/30 is shown to possess hydrogen bond acceptor properties suitable for the separation of polyphenolic solutes such as phenolic acids, flavonols and flavonoids. The separation is achieved isocratically in the presence of solvent mixtures of acetic acid and ethanol. The extent of hydrogen bond adsorption is reviewed based on data obtained from the elution behaviour of a variety of simple polyphenolic solutes including dihydroxybenzoic acids.

  • 7. Hao, Dong-Xia
    et al.
    Sandstrom, Corine
    Huang, Yong-Dong
    Kenne, Lennart
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Ma, Guang-Hui
    Su, Zhi-Guo
    Residue-level elucidation of the ligand-induced protein binding on phenyl-argarose microspheres by NMR hydrogen/deuterium exchange technique2012Ingår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 8, nr 23, s. 6248-6255Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Protein-ligand interactions on liquid-solid interfaces governed the design of functional biomaterials. However, accurate residue details of ligand induced protein binding and unfolding on an interface were still unknown by the current ensemble of protein structure characterizations. Here, a hydrogen/deuterium (H/D) approach coupled with analysis of NMR TOCSY spectra and the solvent accessible surface area (SASA) was designed to enable residue level understanding of lysozyme adsorbed at a phenyl-ligand modified surface. Results showed that the binding sites and unfolding of lysozyme molecules on phenyl-agarose microspheres demonstrated significant ligand-density dependence and protein-coverage dependence. Either increasing ligand density or decreasing adsorption coverage would lead to more binding sites and unfolding of the protein molecules. With the multipoint adsorption strengthening, the protein molecule changed from lying end-on to side-on. Finally, Molecular Dock simulation was utilized to evaluate the NMR determined binding sites based on energy ranking of the binding. It confirmed that this NMR approach represents a reliable route to in silico abundant residue-level structural information during protein interaction with biomaterials.

  • 8.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    L´histoire du développement du Sephadex2005Ingår i: LÓperon:: Bulletin de L´UPBM, Vol. 33, s. 2-11Artikel i tidskrift (Refereegranskat)
  • 9.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    ´L´histoire du développement du Sephadex2005Ingår i: L´Operon: Bulletin de L´UPBM, Vol. 33, s. 2-11Artikel i tidskrift (Refereegranskat)
  • 10.
    Janson, Jan-Christer
    Uppsala universitet, Centrum för ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    The Development of Gel Media and Columns for Large-Scale Chromatography of Proteins, a Historical Review2002Ingår i: Chinese J. Chem. Eng, Vol. 10, nr 6, s. 690-695Artikel i tidskrift (Refereegranskat)
  • 11.
    Janson, Jan-Christer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Jönsson, J. Å.
    Introduction to chromatography2011Ingår i: Protein Purification, Principles, High Resolution Methods and Applications / [ed] J-C Janson, John Wiley & Sons Inc. , 2011, 3, s. 25-50Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 12.
    Jansson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi. Ytbioteknik.
    Affinity 20052006Ingår i: Journal of Molecular Recognition, Vol. 19, nr 4, s. 247-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    No abstract

  • 13.
    Larsson, Anna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi.
    Anderson, Lars
    Xu, Bingze
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Muñoz, Inés
    Usòn, Isabel
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Stålbrand, Henrik
    Ståhlberg, Jerry
    Three-dimensional crystal structure and enzymic characterization of beta-mannanase Man5A from blue mussel Mytilus edulis2006Ingår i: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 14, nr 357, s. 1500-1510Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Endo-beta-1,4-d-mannanase is the key depolymerizing enzyme for beta-1,4-mannan polymers present in the cell walls of plants and some algae, as well as in some types of plant seeds. Endo-1,4-beta-mannanase from blue mussel Mytilus edulis (MeMan5A) belongs to the glycoside hydrolase (GH) family 5 enzymes. The MeMan5A structure has been determined to 1.6A resolution using the multiple-wavelength anomalous dispersion method at the selenium K edge with selenomethionyl MeMan5A expressed in the yeast Pichia pastoris. As expected for GH 5 enzymes, the structure showed a (betaalpha)(8)-barrel fold. An unusually large number of histidine side-chains are exposed on the surface, which may relate to its location within the crystalline style of the digestive tract of the mussel. Kinetic analysis of MeMan5A revealed that the enzyme requires at least six subsites for efficient hydrolysis. Mannotetraose (M4) and mannopentaose (M5) were shown to interact with subsites -3 to +1, and -3 to +2, respectively. A clear kinetic threshold was observed when going from M4 to M5, indicating that the +2 subsite provides important interaction in the hydrolysis of short oligomeric mannose substrates. The catalytic centre motif at subsite -1 found in superfamily GH clan A is, as expected, conserved in MeMan5A, but the architecture of the catalytic cleft differs significantly from other GH 5 enzyme structures. We therefore suggest that MeMan5A represents a new subfamily in GH 5.

  • 14.
    Larsson, Anna M.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Anderson, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Xu, Bingze
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Muñoz, Inés G.
    Usón, Isabel
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Stålbrand, Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Ståhlberg, Jerry
    Three-dimensional Crystal Structure and Enzymic Characterization of β-Mannanase Man5A from Blue Mussel Mytilus edulis2006Ingår i: Journal of Molecular Biology, Vol. 357, nr 5, s. 1500-1510Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Endo-β-1,4-d-mannanase is the key depolymerizing enzyme for β-1,4-mannan polymers present in the cell walls of plants and some algae, as well as in some types of plant seeds. Endo-1,4-β-mannanase from blue mussel Mytilus edulis (MeMan5A) belongs to the glycoside hydrolase (GH) family 5 enzymes. The MeMan5A structure has been determined to 1.6 resolution using the multiple-wavelength anomalous dispersion method at the selenium K edge with selenomethionyl MeMan5A expressed in the yeast Pichia pastoris. As expected for GH 5 enzymes, the structure showed a (βα)8-barrel fold. An unusually large number of histidine side-chains are exposed on the surface, which may relate to its location within the crystalline style of the digestive tract of the mussel. Kinetic analysis of MeMan5A revealed that the enzyme requires at least six subsites for efficient hydrolysis. Mannotetraose (M4) and mannopentaose (M5) were shown to interact with subsites −3 to +1, and −3 to +2, respectively. A clear kinetic threshold was observed when going from M4 to M5, indicating that the +2 subsite provides important interaction in the hydrolysis of short oligomeric mannose substrates. The catalytic centre motif at subsite −1 found in superfamily GH clan A is, as expected, conserved in MeMan5A, but the architecture of the catalytic cleft differs significantly from other GH 5 enzyme structures. We therefore suggest that MeMan5A represents a new subfamily in GH 5.

  • 15. Li, Jing-Jing
    et al.
    Venkataramana, Musturi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Teknisk-naturvetenskapliga fakulteten, Biologiska sektionen, Institutionen för cell- och molekylärbiologi. Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Sanyal, Suparna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Teknisk-naturvetenskapliga fakulteten, Biologiska sektionen, Institutionen för cell- och molekylärbiologi. Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Janson, Jan-Christer
    Institutionen för ytbioteknik med Centrum för ytbioteknik. Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Su, Zhi-Guo
    Immobilized β-cyclodextrin polymer coupled to agarose gel properly refolding recombinant Staphylococcus aureus elongation factor-G in combination with detergent micelle2006Ingår i: Protein Expression and Purification, Vol. 45, nr 1, s. 72-79Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel artificial chaperone system using a combination of interactions between the unfolded protein, a detergent and a chromatographic column packed with immobilized β-cyclodextrin (β-CD) polymer coupled to an agarose gel, was introduced to refold recombinant Staphylococcus aureus elongation factor-G (EF-G). Pre-mixing of 10% Triton X-100 and unfolded EF-G at 24 mg/ml followed by a 20-fold dilution into refolding buffer led to successful capturing of EF-G by Triton X-100 resulting in formation of a detergent–protein complex at 1.2 mg/ml of final protein concentration. The complex was subsequently applied to the immobilized β-CD polymer column resulting in correct refolding of EF-G at a concentration of 530 μg/ml with 99% mass recovery. Detergent concentrations above critical micelle concentration were required for efficient capturing of EF-G at high protein concentration. Other detergents with hydrophile–lipophile-Balance values similar to that of Triton X-100 (Triton N-101, Noindet P40 (NP40), and Berol 185) also produced similar result. Soluble polymerized β-CD was more efficient than the monomer to remove the detergent from the protein complex in a batch system. Immobilized β-CD polymer column further improved the capability of detergent removal and was able to prevent aggregation that occurred with the addition of soluble β-CD polymer at high protein concentration in the batch system. The mechanism for this system-assisted refolding was tentatively interpreted: the released protein could correctly refold in an enclosed hydrophilic environment provided by the integration of matrix and β-CD polymer, and thus avoided aggregation during detergent removal.

  • 16. Li, Jing-Jing
    et al.
    Venkataramana,, Musturi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Teknisk-naturvetenskapliga fakulteten, Biologiska sektionen, Institutionen för cell- och molekylärbiologi.
    Wang, Ai-Qing
    Sanyal, Suparna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Teknisk-naturvetenskapliga fakulteten, Biologiska sektionen, Institutionen för cell- och molekylärbiologi.
    Janson, Jan-Christer
    Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Su, Zhi-Guo
    A mild hydrophobic interaction chromatography involving polyethylene glycol immobilized to agarose media refolding recombinant Staphylococcus aureus elongation factor G2005Ingår i: Protein Expression and Purification, Vol. 40, nr 2, s. 327-335Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recombinant Staphylococcus aureus elongation factor G (EF-G) is difficult to refold by dilution due to the formation of large amounts of misfolded structures. However, refolding of EF-G by adsorption to a chromatographic column packed with immobilized polyethylene glycol 20,000 (PEG 20 K) followed by pulse elution with 8 M urea resulted in 88% mass recovery and 80% of correctly refolded structure. The PEG 20 K was coupled to brominated allyl group derivatized Sepharose High Performance to construct a mild hydrophobic adsorbent. Various other hydrophobic interaction adsorbents were also attempted to refold EF-G. However, ligands with high hydrophobicity tended to misfold EF-G, resulting in irreversible adsorption. Various solvents, detergents, and low temperature as well as 8 M urea were tried to release bound EF-G. Only pulse elution with 8 M urea was efficient. Urea concentrations favorable for efficiently refolding EF-G were investigated. Low urea concentration produced more misfolded structures.

  • 17. Liu, Dan
    et al.
    Ma, Yan
    Gu, Ming
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Wang, Changhai
    Xiao, Hongbin
    Liquid-liquid/solid three-phase high-speed counter-current chromatography, a new technique for separation of polyphenols from Geranium wilfordii Maxim2012Ingår i: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 35, nr 16, s. 2146-2151Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-speed counter-current chromatography using a new liquidliquid/solid three-phase system was used for the separation of the polyphenols corilagin and geraniin from a crude extract of Geranium wilfordii Maxim in one step. The optimized three-phase system was composed of n-hexane/ethyl acetate/methanol/acetic acid/water and to which was added 10-mu m average diameter microspheres of cross-linked 12% agarose at the ratio of 0.2:10:2:1:5 and 0.1 g/mL, respectively. The purities of geraniin and corilagin were 82 and 90%, which were determined by HPLC at 280 nm. A 14.5 and 7 mg of geraniin and corilagin were purified from 160 mg crude extract with the yields of 70 and 78%, respectively.

  • 18. Luo, Jian
    et al.
    Leeman, Mats
    Ballagi, Andras
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Elfwing, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Su, Zhiguo
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Wahlund, Karl-Gustav
    Size characterization of green fluorescent protein inclusion bodies in E. coli using asymmetrical flow field-flow fractionation–multi-angle light scattering2006Ingår i: J. of Chromatography A, Vol. 1120, nr 1-2, s. 158-164Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The goal of this study was to investigate the applicability of asymmetrical flow field-flow fractionation–multi-angle light scattering (AsFlFFF-MALS) for size analysis of green fluorescent protein inclusion bodies (GFPIBs). The size distributions of GFPIBs prepared by various culture conditions were determined. For GFPIBs prepared at 37 °C the peak maximum hydrodynamic diameter (dH) first increased and then decreased with the increase of the induction times in the presence of 0.1 and 2 mM isopropyl-β-d-thiogalactoside (IPTG). For GFPIBs prepared at 30 °C the peak maximum dH was constant at about 700 nm irrespectively of the induction times and IPTG concentrations.

  • 19. Xu, J.
    et al.
    Sandström, C.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik.
    Tan, T.
    Chromatographic retention of epigallocatechin gallate on oligo-beta-cycloclextrin coupled sepharose media investigated using NMR2006Ingår i: Chromatographia, ISSN 0009-5893, E-ISSN 1612-1112, Vol. 64, nr 1-2, s. 7-11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The retention of epigallocatechin gallate (EGCG) on oligo-β-cyclodextrin (oligo-β-CD) bonded agarose chromatographic media was investigated. NMR spectroscopy in solution showed that the EGCG immerses into the β-CD cavity. The association constant calculated by NMR titration was used to estimate a retention factor which accurately reflected chromatographic behaviour. This correlation suggests that oligo-β-CD forms inclusion complexes with EGCG via the same mechanism as monomeric β-CD.

  • 20.
    Xu, Jianqiang
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Yang, Qing
    Qian, Xuhong
    Samuelsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Assessment of 4-nitro-1,8-naphthalic anhydride reductase activity in homogenates of bakers' yeast by reversed-phase high-performance liquid chromatography2007Ingår i: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 847, nr 2, s. 82-87Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A simple reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the simultaneous determination of yield and conversion ratio of 4-nitro-1,8-naphthalic anhydride to 4-amino-1,8-naphthalic anhydride following incubation with a crude bakers’ yeast homogenate. The analytes were separated on a C18 column in gradient mode. The detection limit of 4-amino-1,8-naphthalic anhydride is 10 ng/μl when using a 10 μl sample injection volume. The nitroreductase activity in the homogenate system can be assessed during the bioconversion process. The method can be used for the simultaneous detection of 4-hydroxylamino-1,8-naphthalic anhydride, an intermediate with limited stability.

  • 21. Xu, Jun
    et al.
    Tan, Tianwei
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Mixed-mode retention mechanism for (-)-epigallocatechin gallate on a 12% cross-linked agarose gel media2006Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1137, nr 1, s. 49-55Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The adsorption behaviour of (−)-epigallocatechin gallate (EGCG), the major polyphenolic substance in green tea extracts, on the cross-linked agarose gel Superose 12 HR 10/30, has been studied using a variety of solvent systems and shown to be based on a mixture of hydrogen bonding and hydrophobic interaction. The hydrogen bonding was studied in acetonitrile in the presence of different co-solvents possessing varying hydrogen bond donor (HBD) and/or hydrogen bond acceptor (HBA) characteristics. The HBA-value of the co-solvent had the highest effect whereas the HBD-value played a subordinate role. Retention due to hydrophobic interaction could be demonstrated when mobile phases containing high water content were applied. The retention of EGCG, and its analogues (−)-epigallocatechin (EGC) and (−)-catechin (C) were thus shown to be dependent on the polarity of the organic modifiers added. However, the elution order of EGC and C, was inversed to that observed in reversed phase chromatography, indicating that some hydrogen bonding was still in effect. The retardation of EGCG in the presence of a wide concentration range of acetonitrile in water confirmed the interpretation that the retention mechanism is of mixed-mode character based on both hydrogen bonding and hydrophobic interaction.

  • 22. Xu, Jun
    et al.
    Tan, Tianwei
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    One-step purification of epigallocatechin gallate from crude green tea extracts by mixed-mode adsorption chromatography on highly cross-linked agarose media2007Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1169, nr 1-2, s. 235-238Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    (−)-Epigallocatechin gallate (EGCG) was purified in one step from a green tea polyphenol (GTP) crude extract by adsorption chromatography on a Superose 12 HR 10/30 column. The mobile phase used was a mixture of acetonitrile and water with an optimum mobile phase compositions regarding purity, recovery and separation time of 78/22 (v/v). Maximum practical sample loading was 100 mg GTP per run (corresponding to 4.2 mg/ml Superose). An EGCG purity of 99% with recoveries in the range 60–65% was achieved in one step directly from the crude GTP extract. Full column regeneration was obtained using solvents in the following order: 0.5 M NaOH, distilled water and 30% acetic acid.

  • 23. Xu, Jun
    et al.
    Tan, Tianwei
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    One-step simultaneous purification of three water-soluble constituents in crude extracts from Danshen by adsorption chromatography on oligo-β-cyclodextrin substituted agarose gel media2007Ingår i: Process Biochemistry, ISSN 1359-5113, E-ISSN 1873-3298, Vol. 42, nr 3, s. 480-485Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new adsorption chromatographic method for the simultaneous purification of Danshensu, Protocatechuic aldehyde and Salvianolic acid B (Lithospermic acid B) from a crude extract from radix of Danshen (Salviae miltiorrhiza) has been developed using oligo-β-cyclodextrin immobilized to Sepharose HP agarose gel media. Sample loads of up to 2.3 mg crude extracts/ml gel gave satisfactory results. The target components were eluted using step-wise isocratic elution with increasing concentrations of acetic acid. The separated fractions were identified by LC–MS. The recoveries of Danshensu, Protocatechuic aldehyde and Salvianolic acid B were 88.3%, 90.2% and 73.6% with purities of 99%, 99%, and 98%, respectively. Isocratic elution in 6% acetic acid gave baseline separation of Danshensu and Protocatechuic aldehyde, whereas 40% acetic acid was required for purification of Salvianolic acid B. Full separation efficiency could be restored by cleaning the column with 0.5 M NaOH followed by distilled water and 30% acetic acid.

  • 24. Xu, Jun
    et al.
    Tan, Tianwei
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Kenne, Lennart
    SLU.
    Sandström, Corine
    SLU.
    NMR Studies on the interaction between (−)-epigallocatechin gallate and cyclodextrins, free and bonded to silica gels2007Ingår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 342, nr 6, s. 843-850Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The interaction between (−)-epigallocatechin-3-gallate (EGCG) and β- or γ-cyclodextrin (CD), in free solution and bonded to silica beads, has been studied by 1H HR-MAS NMR spectroscopy. The chromatographic retardation of EGCG on columns packed with CD-silica beads was shown to be due to the interaction of EGCG with the CD ligands because no nonspecific interaction with the silica gel could be observed. EGCG forms a tighter complex with β-CD than with γ-CD and NMR data obtained from hydroxy protons together with mm2 calculations suggest that for β-CD intermolecular hydrogen bonding, in addition to hydrophobic interaction, stabilizes the complex.

  • 25. Xu, Jun
    et al.
    Zhang, Guifeng
    Tan, Tianwei
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    One-step purification of epigallocatechin gallate from crude green tea extracts by isocratic hydrogen bond adsorption chromatography on β-cyclodextrin substituted agarose gel media2005Ingår i: Journal of Chromatography B, Vol. 824, nr 1-2, s. 323-326Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An oligomerized β-cyclodextrin ligand coupled to brominated allyl-group substituted Sepharose HP has been used for the one-step purification of polyphenolic epigallocatechin gallate (EGCG), an important antioxidant, by isocratic hydrogen bond adsorption chromatography. With a sample load of 1.33 mg crude green tea polyphenolic extract per ml column packing and with water/ethanol/acetonitrile (57/30/13, v/v) as the optimum mobile phase, an EGCG purity of about 98% with a recovery of approximate 73% could be achieved by proper peak cutting. After about 10 sample applications, the column performance started to deteriorate but could be regenerated to its original function by cleaning with 0.35 M NaOH.

  • 26. Yang, Li
    et al.
    Zhu, Yan
    Tan, Tianwei
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik.
    Coupling oligo-β-cyclodextrin on polyacrylate beads media for separation of puerarin2007Ingår i: Process Biochemistry, ISSN 1359-5113, E-ISSN 1873-3298, Vol. 42, nr 7, s. 1075-1083Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The isoflavonoid puerarin, a well-known bioactive constituent in traditional Chinese medicine, can be separated from other isoflavonoids in the extracts of Radix puerariae (root of the plant Pueraria lobata) on oligo-β-cyclodextrin ligand coupled to D152 beads. The parameters of coupling time, temperature, solvent system and molar ratio of reactants were tested to optimize the preparation conditions. Acetic acid (7%) was used as the optimum mobile phase. The fine particle sizes of the coupled microspheres packing displayed high resolving power and efficiency. Compared with other two polyacrylate carrier media, PGMA-CDP and PHEMA-CDP, various retention mechanisms such as β-CD inclusion complexation, hydrogen bond interaction, and π–π interaction might exist in the chromatography process. This study provides a novel alternative matrix for the separation of puerarin.

  • 27.
    Yang, Qing
    et al.
    Uppsala universitet, Centrum för ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Xu, Xiaoming
    Li, Min
    Yuan, Xiaodong
    Su, Zhiguo
    Janson, Jan-Christer
    Uppsala universitet, Centrum för ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    An, Lijia
    Cloning and expression of defibrase cDNA from the venom of Gloydius Shedaoensis2002Ingår i: Biotechnology Letters, Vol. 24, s. 135-138Artikel i tidskrift (Refereegranskat)
  • 28. Zhao, Xi
    et al.
    Wu, Jie
    Gong, Fang-Ling
    Cui, Jin-Mei
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Analytisk kemi.
    Ma, Guang-Hui
    Su, Zhi-Guo
    Preparation of uniform and large sized agarose microspheres by an improved membrane emulsification technique2014Ingår i: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 253, s. 444-452Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The SPG (Shirasu porous-glass) membrane emulsification technique has been subject to much attention for the preparation of uniform emulsions. However, so far primarily used for the production of droplets with sizes below approximately 60 mu m. A production bottleneck occurred if the desired size was further increased, especially when highly viscous dispersed phases were involved. To this end, an improved membrane emulsification technique was proposed and has been applied to the preparation of large agarose microspheres, with a size of around 90 mu m and with a narrow size distribution. The effects of important emulsification parameters, including the pore size of the SPG membrane, the operating pressure, the stirring rate of the continuous phase, the composition of the continuous oil phase, and the concentration of agarose in the dispersed water phase, have been extensively studied. Under optimum conditions, uniform-size agarose microspheres with an average diameter of 93 pm and a size distribution index of 0.65 were successfully prepared. The average particle size of the home-made agarose microspheres was almost identical to that of the commercial product Sepharose 4 Fast Flow (4FF), which is produced by mechanical stirring and an additional sieving process. However, the size distribution of the former was much narrower than that of the latter. Therefore, the improved membrane emulsification technique presented here is promising for the application of high viscosity systems such as agarose solutions, and the production scale can be further enhanced by increasing the number of membrane units attached to the experimental apparatus. (C) 2013 Elsevier B.V. All rights reserved.

  • 29. Zhou, Weibin
    et al.
    Bi, Jingxiu
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för ytbioteknik med Centrum för ytbioteknik. Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi.
    Dong, Aihua
    Li, Yan
    Zhang, Yan
    Huang, Yongdong
    Su, Zhiguo
    Ion-exchange chromatography of hepatitis B virus surface antigen from a recombinant Chinese hamster ovary cell line2005Ingår i: Journal of Chromatography A, Vol. 1095, nr 1-2, s. 119-125Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    About 10% of the Chinese population are chronic carriers of hepatitis B virus (HBV). Thus, the development of a highly efficient process for the preparation of a vaccine based on a recombinant hepatitis B surface antigen (HBsAg) is very important to the Chinese national immunization program. To this end, the ion exchange chromatography recovery of CHO-HBsAg from a recombinant Chinese hamster ovary cell line was shown to increase from about 55 to 80% by the addition of 1% poly(ethylene glycol) (PEG 10,000) to the mobile phase. Furthermore, based on analysis by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE), the intact glycoprotein form of CHO-HBsAg was completely preserved by the addition of PEG. In the absence of PEG the glycoprotein form of CHO-HBsAg was also spread out into the high salt elution fraction. High-performance size-exclusion chromatography with on-line multiangle-laser-light scattering (HPSEC-MALLS) analysis was performed to monitor the status of the CHO-HBsAg aggregate structure assembly, particle size and molecular weight distribution after each purification step, and the results showed further that the presence of PEG facilitated the separation and recovery of intact glycoprotein form of CHO-HBsAg and promoted their assembly to proper virus-like particles, which are both important features and prerequisites of their immunogenicity.

  • 30. Zhou, Weibin
    et al.
    Bi, Jingxiu
    Janson, Jan-Christer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Ytbioteknik. Ytbioteknik.
    Li, Yan
    Huang, Yongdong
    Zhang, Yan
    Su, Zhiguo
    Molecular characterization of recombinant Hepatitis B surface antigen from Chinese hamster ovary and Hansenula polymorpha cells by high-performance size exclusion chromatography and multi-angle laser light scattering2006Ingår i: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 838, nr 2, s. 71-77Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The molecular weight and size of recombinant Hepatitis B surface antigen (HBsAg) derived from Chinese hamster ovary (CHO) and the Hansenula polymorph have been characterized by high-performance size exclusion chromatography with multi-angle laser light scattering (HPSEC-MALLS). The average molecular weight of CHO-derived HBsAg particle (CHO-rHBsAg) (4921 kDa) was higher than that of H. polymorpha yeast strain (Hans-rHBsAg) (3010 kDa). The size of CHO-rHBsAg (22.1 nm) is nearly the same as that of native HBsAg compared to 18.1 nm for Hans-rHBsAg. The average monomer numbers were found to be 155 for CHO-rHBsAg and 86 for Hans-rHBsAg, respectively. The data obtained support the assumption that the higher immunogenicity of CHO-derived HBsAg is related to its more favorable macromolecular assembly structure.

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