Professor Svein Valla

Professor Svein Valla

Publications 1995- in international journals with referee (Vallas group)

  1. Ertesvåg, H., Høidal, H., Hals, I., Rian, A., Doseth, B., and Valla, S. 1995. A family of modular type mannuronan C-5-epimerase genes controls alginate structure in Azotobacter vinelandii. Molec. Microbiol. 16: 719-731.
  2. Haugan, K., Karunakaran, P., Tøndervik, A., and Valla, S. 1995. The host range of RK2 minimal replicon copy-up mutants is limited by species-specific differences in the maximum tolerable copy number. Plasmid 33: 27-39.
  3. Rehm, B.H., Ertesvåg, H., and Valla, S. 1996. A new Azotobacter vinelandii mannuronan C-5-epimerase gene (algG) is part of an alg gene cluster physically organized as in Pseudomonas aeruginosa. J. Bacteriol. 178: 5884-5889.
  4. Valla, S, and Skjåk-Bræk, G. 1996. Alginate - a target molecule for genetic engineers and a versatile material for the biotechnologist. Agro Food Industry hi-tech. Sept./Oct. issue page 38-41.
  5. Ertesvåg, H., Skjåk-Bræk, G., and Valla, S. 1996. Genetics and biosynthesis of alginates. Carbohydr. Res. May issue, page 14-18.
  6. Blatny, J., Brautaset, T., Winther-Larsen, H., Haugan, K., and Valla, S. 1997. Construction and use of a versatile set of cloning and expression vectors based on the RK2 replicon. Appl. Env. Microbiol. 63: 370-379.
  7. Blatny, J., Brautaset, T., Winther-Larsen, H., Karunakaran, P., and Valla, S. 1997. Improved broad-host-range RK2 vectors for high and low regulated gene expression levels in gram-negative bacteria. Plasmid 38: 35-51.
  8. Rehm, B.H.A., and Valla, S. 1997. Bacterial alginates: Biosynthesis and applications. Appl. Microbiol. Biotechnol. 48: 282-288.
  9. Brautaset, T., Petersen, S., and Valla, S. 1997. An experimental study in Escherichia coli of parameters affecting carbon flow in a metabolic pathway. Biotechnol. and Bioeng.58: 299-302.
  10. Karunakaran, P., Blatny, J.M., Ertesvåg, H., and Valla, S. 1998. Species-dependent phenotypes of replication-temperature-sensitive trfA mutants of plasmid RK2: a codon-neutral base substitution stimulates temperature sensitivity by leading to reduced levels of trfA expression. J. Bacteriol. 180: 3793-3798.
  11. Ertesvåg, H., and Valla, S. 1998. Biosynthesis and applications of alginates. Polymer Degr. and Stabil. 59: 85-91.
  12. Ertesvåg, H., Erlien, F., Skjåk-Bræk, G., Rehm, B.H.A. 1998. Biochemical properties and substrate specificities of a recombinantly produced Azotobacter vinelandii alginate lyase. J. Bacteriol. 180: 3779-3784.
  13. Ertesvåg, H., and Valla, S. 1998. Bacterial alginate synthesis and the mannuronan C-5-epimerase system in Azotobacter vinelandii. Proceedings from The International Symposium on Biochemical Principles and Mechanisms of Biosynthesis and Biodegradation of Polymers, Munster, June 3-6. Wiley, VCH, pp. 176-184.
  14. Valla, S. 1998. Broad-host-range plasmids and their role in gene transfer in nature. APMIS Suppl. 84: 19-24.
  15. Ertesvåg, H., Høidal, H., Skjåk-Bræk, G., and Valla, S. 1998. The Azotobacter vinelandii mannuronan C-5-epimerase AlgE1 consists of two seperate catalytic domains. J. Biol. Chem. 273: 30927-30932.
  16. Svanem, B.I.G., Skjåk-Bræk, G., Ertesvåg, H., and Valla, S. 1999. Cloning and expression of three new Azotobacter vinelandii genes closely related to a previously described gene family encoding mannuronan C-5-epimerases. J. Bacteriol. 181: 68-77.
  17. Høidal, H.K., Ertesvåg, H., Skjåk-Bræk, G., Stokke, B.T.,and Valla, S. 1999. The recombinant Azotobacter vinelandii mannuronan C-5-epimerase AlgE4 epimerizes alginate by a non-random attack mechanism. J. Biol. Chem. 274: 12316-12322.
  18. Ertesvåg, H., and Valla, S. 1999. The A-modules of the Azotobacter vinelandii mannuronan C-5-epimerase AlgE1 are sufficient both for epimerization and binding of Ca2+. J. Bacteriol. 181: 3033-3038.
  19. Ramstad, M.V., Ellingsen, T., Josefsen, K., Høidal, H.K., Valla, S., Skjåk-Bræk, G., and Levine, D.W. 1999. Properties and action pattern of the recombinant mannuronan C-5-epimerase AlgE2. Enzyme and Microb. Technol. 24: 636-646.
  20. Sekurova, O., Sletta, H., Ellingsen, T.E., Valla, S., and Zotchev, S. 1999. Molecular cloning and analysis of a pleiotropic regulatory gene locus from the nystatin producer Streptomyces noursei ATCC11455. FEMS Microbiol. 177: 297-304.
  21. Karunakaran,P., Endresen, T., Ertesvåg, H., Blatny, J.M., and Valla, S. 1999. A small derivative of the broad-host-range plasmid RK2 which can be switched from a replicating to a non-replicating stage as a response to an externally added inducer. FEMS Microbiol. Lett. 180: 221-227.
  22. Ertesvåg, H., Høidal, H., Schjerven, H., Svanem, B.I., and Valla, S. 1999. Mannuronan C-5-epimerases and their applications for in vitro and in vivo design of new alginates useful in biotechnology. Metabolic Engineering. 1: 262-269.
  23. Winther-Larsen, H.C, Josefsen, K.D., Brautaset, T., and Valla, S. 2000. Parameters affecting gene expression from the Pm promoter in gram-negative bacteria. Metabolic Engineering. 2: 79-91.
  24. Winther-Larsen, H.C., Blatny, J.M., Valand, B., Brautaset, T., and Valla, S. 2000. Pm promoter expression mutants and their use in broad-host-range RK2 plasmid vectors. Metabolic Engineering. 2:92-103.
  25. Santos, P.M., Blatny, J.M., Bartolo, I.D., Valla, S., and Zennaro, E. 2000. Physiological analysis of the expression of the styrene degradation gene cluster in Pseudomonas fluorescens ST. Appl. Env. Microbiol. 66: 1305-1310.
  26. Høidal, H., Svanem, B.I., Gimmestad, M., and Valla, S. 2000. Mannuronan C-5- epimerases and cellular differentitation of Azotobacter vinelandii.Env. Microbiol. 2: 27-38.
  27. Zotchev, S., Haugan, K., Sekurova, O., Ellingsen, T., and Valla, S. 2000. Identification of a gene cluster for antibacterial polyketide-derived antibiotic biosynthesis in the nystatin producer Streptomyces noursei ATCC 11455. Microbiology 146: 611-619.
  28. Brautaset, T., Petersen, S.B., and Valla, S. 2000. In vitro and in vivo characteristics of phosphoglucomutase enzyme mutants. Metabolic Engineering 2: 104-114.
  29. Draget, K.I., Strand, B., Hartmann, M., Valla, S., Smidsrød, O., and Skjåk-Bræk, G. 2000. Ionic and gel formation of epimerised alginates: the effect of AlgE4. Int. J. Biol. Macromol. 27: 117-122.
  30. Brautaset, T., Sekurova, O.N., Sletta, H., Ellingsen, T.E., Strøm, A., Valla, S., and Zotchev, S. 2000. Biosynthesis of the polyene antifungal antibiotic nystatin in Streptomyces noursei ATCC 11455: analysis of the gene cluster and deduction of the biosynthetic pathway. Chem. Biol. 7: 395-403.
  31. Svanem, B.I.G., Strand, W.I., Skjåk-Bræk, G., Ertesvåg, H., and Valla, S. 2001. The catalytic activity of the Azotobacter vinelandii mannuronan C-5-epimerase and alginate lyase AlgE7 probably originate from the same active site in the enzyme. J. Biol. Chem. 276: 31542-31550.
  32. Santos, P.M., Bartolo, I.D., Blatny, J.M., Zennaro, E., and Valla, S. 2001. New broad-host-range promoter probe vectors based on the plasmid RK2 replicon. FEMS Microbiol. Lett. 195: 91-96.
  33. Valla, S., Li, J., Ertesvåg, H., and Lindahl, U. 2001. Hexuronyl C5-epimerases in alginate and glycosaminoglycan biosynthesis. Biochimie 83: 819-830.
  34. Brautaset, T., Bruheim, P., Sletta, H., Hagen, L., Ellingsen, T., Strøm, A., Valla, S., and Zotchev, S.B. 2002. Hexaene derivatives of the polyene antifungal antibiotic nystatin produced as a result of an induced rearrangement within the nysC polyketide synthase gene in Streptomyces noursei ATCC 11455. Chem. Biol. 9: 367-373.
  35. Hartmann, M., Duun, A.S., Markussen, S., Grasdalen, H., Valla, S., and Skjåk-Bræk, G. 2002. Time-resolved 1H and 13C NMR spectroscopy for detailed analyses of the Azotobacter vinelandii mannuronan C-5-epimerase reaction. Biochem. Biophys. Acta. 1570: 104-112.
  36. Jain, S., Franklin, M.J. Ertesvåg, H., Valla, S., and Ohman, D.E. 2003. The dual roles of AlgG in C-5-epimerization and secretion of alginate polymers in Pseudomonas aeruginosa. Mol. Microbiol. 47: 1123-1133.
  37. Gimmestad, M., Sletta, H., Ertesvåg, H., Bakkevig, K., Jain, S., Suh, S., Skjåk-Bræk, G., Ellingsen, T., Ohman, D., and Valla, S. 2003. The Pseudomonas fluorescens AlgG protein, but not its mannuronan C5-epimerases activity, is needed for alginate polymer formation. J. Bacteriol. 185: 3515-3523.
  38. Blatny, J., Ertesvåg, H., Nes, I.F., and Valla, S. 2003 Heterologous expression in Lactococcus lactis; expression of the Azotobacter vinelandii algE6 gene product displaying mannuronan C-5 epimerase activity. FEMS Microbiol. Lett. 227: 229-235.
  39. Brautaset, T., Jakobsen, Ø.M., Flickinger, M.C, Valla, S., and Ellingsen, T. 2004. Plasmid-dependent methylotrophy in thermotolerant Bacillus methanolicus. J. Bacteriol.186: 1229-1238.
  40. Sekurova, O., Brautaset, T., Sletta, H., Borgos, S.E., Jakobsen, Ø., Ellingsen, T., Strøm, A.R., Valla, S., and Zotchev, S.B. 2004. In vivo analysis of the regulatory genes in the nystatin biosynthetic gene cluster of Streptomyces noursei ATCC 11455 reveals their differential control over antibiotic biosynthesis. J. Bacteriol. 186: 1345-1354.
  41. Bjerkan, T., Lillehov, B.E., Strand, W.I., Skjåk-Bræk, G., Valla, S., and Ertesvåg, H. 2004. Construction of hybrid Azotobacter vinelandii mannuronan C5-epimerases with new epimerization pattern characteristics. Biochem. J. 381: 813-821.
  42. Bjerkan, T.M., Bender, C.L., Fakhr, M.K., Preston, L.A., Ertesvåg. H., Drabløs, F., and Valla, S. 2004. Pseudomonas syringae encodes a combined mannuronan C5-epimerase-O-acetyl hydrolase, which can strongly enhance the gel-forming properties of alginates. J. Biol. Chem. 279: 28920-28929.
  43. Sletta, H., Nedal, A., Aune., T.E.V., Hellebust, H., Hakvåg, S., Aune, R., Ellingsen, T.E., Valla, S., and Brautaset, T. 2004. Broad-host-range plasmid pJB658 can be used for industrial level production of a secreted host-toxic single-chain antibody fragment in Escherichia coli. Appl. Env. Microbiol. 70: 7033-7039.
  44. Robles-Price, A., Wong, T.Y., Sletta, H., Valla, S., and Schiller, N.L. 2004. AlgX is a periplasmic protein required for alginate biosynthesis in Pseudomonas aeruginosa. J. Bacteriol. 186: 7369-7377.
  45. Aachmann, F.L., Svanem, B.I.G., Valla, S., Petersen, S.B., and Wimmer, R. 2005. NMR assignment of the R-module from the Azotobacter vienlandii mannuronan C5-epimerase AlgE4. J. Biomolec. NMR. 31: 259-260.
  46. Bakkevig, K., Sletta, H., Gimmestad, M., Aune, R., Ertesvåg, H., Degnes, K., Christensen,B.E., Ellingsen, T.E., and Valla, S. 2005.Role of the Pseudomonas fluorescens alginate lyase (AlgL) in cleaning the periplasm of alginates not exported to the extracellular environment. J. Bacteriol. 187: 8375-8384.
  47. Aaacmann, F.L., Svanem, B.I.G., Güntert, P, Petersen, S.B, Valla, S., and Wimmer, R. 2006. NMR structure of the R-module – a parallel ß-roll subunit from an Azotobacter vinelandii mannuronan C-5 epimerase. J. Biol. Chem. In press.

Patents

1. Blatny, J.M., Karunakaran, P., and Valla, S. 2001. Expression vectors based on RK2 and TOL plasmids. US patent No. 6258565 B1.

2. Zotchev, S., Brautaset, T., Sekurova, O., Sletta, H., Fjærvik, E., Ellingsen, T.E., Strøm, A., Valla, S., and Gulliksen, O.-M. 2000. Novel genes encoding a nystatin polyketide synthase and their manipulation and utility. Patent pending: PCT/GB01/0059.

3. Gimmestad, M., Sletta, H., Karunakaran, P., Bakkevig, K., Ertesvåg, Helga., Ellingsen, T., Skjåk-Bræk, G.,Valla, S. 2002. New Mutant Strains ofPseudomonas fluorescens and variantsthereof, methods for their production, and uses thereof in alginate production. (PCT)WO 2004/011628.

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