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  • 1. Abahazi, Emese
    et al.
    Satorhelyi, Peter
    Erdelyi, Balazs
    Vertessy, Beata G.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Paizs, Csaba
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Poppe, Laszlo
    Covalently immobilized Trp60Cys mutant of omega‰-transaminase from Chromobacterium violaceum for kinetic resolution of racemic amines in batch and continuous-flow modes2018In: Biochemical engineering journal, ISSN 1369-703X, E-ISSN 1873-295X, Vol. 132, p. 270-278Article in journal (Refereed)
    Abstract [en]

    Covalent immobilization of an engineered omega-transaminase mutant Trp60Cys from Chromobacterium violaceum (CvTAW60C) was performed on bisepoxide-activated aminoalkyl resins. Activity of the various CvTAW60C preparations was evaluated in kinetic resolution of four racemic amines (rac-1a–d). The most active EA-G-CvTAW60C preparation (CvTAW60C attached to polymeric resin with ethylamine function activated with glycerol diglycidyl ether—EA-G) could perform the kinetic resolution of racemic 4-phenylbutan-2-amine (rac-1a) over 49% conversion up to 19 consecutive reaction cycles or in media containing up to 50% v/v DMSO as cosolvent in batch mode reactions. The immobilization process of CvTAW60C onto the EA-G resin filled in stainless steel bioreactors was also tested in flow-through mode. Kinetic resolution of three racemic amines containing aromatic moieties (rac-1a-c) was performed in continuous-flow mode resulting in easy-to-separate mixture of the corresponding ketone (2a–c) and the non-converted (R)-amine in high enantiopurity (ee(R)-1a-c ≥ 96%).

  • 2.
    Al-Khalili, Lubna
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    de Castro Barbosa, T.
    Östling, J.
    Massart, J.
    Katayama, M.
    Nyström, A. -C
    Oscarsson, J.
    Zierath, J. R.
    Profiling of human myotubes reveals an intrinsic proteomic signature associated with type 2 diabetes2014In: Translational Proteomics, ISSN 2212-9634, Vol. 2, no 1, p. 25-38Article in journal (Refereed)
    Abstract [en]

    The development of insulin resistance and type 2 diabetes (T2D) involves a complex array of metabolic defects in skeletal muscle. An in vitro cell culture system excludes the acute effects of external systemic factors existing in vivo. Thus, we aimed to determine whether intrinsic differences in the protein profile exist in cultured myotubes derived from T2D versus normal glucose tolerant (NGT) healthy people. Applying two dimensional difference gel electrophoresis technology (2-D DIGE), the abundance of 47 proteins differed in myotubes derived from T2D patients versus NGT donors. Proteins involved in fatty acid and amino acid metabolism, TCA cycle, mitochondrial function, mRNA processing, DNA repair and cell survival showed higher abundance, while proteins associated with redox signaling (PARK7; Parkinson disease 7), glutathione metabolism (glutathione S-transferase, GST, isoforms T1, P1 and M2), and protein dynamics (heat shock protein, HSP, isoform B1 and 90A) showed reduced abundance in myotubes derived from T2D versus NGT donors. Consistent with our proteome analysis results, the level of total glutathione was reduced in myotubes obtained from T2D versus NGT donors. Taken together, our data provide evidence for intrinsic differences in the profile of proteins involved in energy metabolism, cellular oxidative stress, protein dynamics and gene regulation in myotubes derived from T2D patients. These differences thereby suggest a genetic or epigenetic influence on protein content level, which can be further investigated to understand the molecular underpinnings of T2D progression and lead to new therapeutic approaches.

  • 3.
    Al-Khalili, Lubna
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Gillner, Karin
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Zhang, Ye
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Åstrand, Carolina
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Shokri, Atefeh
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Hughes-Brittain, Nanaaya
    McKean, Robert
    Robb, Brendan
    Chotteau, Véronique
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Characterization of Human CD133+Cells in Biocompatible Poly(l-lactic acid) Electrospun Nano-Fiber Scaffolds2016In: Journal of Biomaterials and Tissue Engineering, ISSN 2157-9083, E-ISSN 2157-9091, Vol. 6, no 12, p. 959-966Article in journal (Refereed)
    Abstract [en]

    CD133+ cells are potential myogenic progenitors for skeletal muscle regeneration to treat muscular dystrophies. The proliferation of human CD133+ stem cells was studied for 14 days in 3D biomimetic electrospun poly-L-lactic acid (PLLA) nano-fiber scaffolds. Additionally, the myogenic differentiation of the cells was studied during the last 7 days of the culture period. The cells were homogeneously distributed in the 3D scaffolds while colony formation and myotube formation occurred in 2D. After a lag phase due to lower initial cell attachment and an adaptation period, the cell growth rate in 3D was comparable to 2D after 7 and 14 days of culture. The expression of the stem cell (SC) marker PAX7 was 1.5-fold higher in 3D than 2D while the differentiation markers MyoG, Desmin and MyoD were only slightly changed (or remain unchanged) in 3D but strongly increased in 2D (12.6, 3.9, and 7.9-fold), and the myotube formation observed in 2D was absent in 3D. The marker expression during proliferation and differentiation, together with the absence of myotubes in 3D, indicates a better maintenance of stemness in 3D PLLA and stronger tendency for spontaneous differentiation in 2D culture. This makes 3D PLLA a promising biomaterial for the expansion of functional CD133+ cells.

  • 4.
    Anderson, Mattias
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Amine Transaminases in Multi-Step One-Pot Reactions2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amine transaminases are enzymes that catalyze the mild and selective formation of primary amines, which are useful building blocks for biologically active compounds and natural products. In order to make the production of these kinds of compounds more efficient from both a practical and an environmental point of view, amine transaminases were incorporated into multi-step one-pot reactions. With this kind of methodology there is no need for isolation of intermediates, and thus unnecessary work-up steps can be omitted and formation of waste is prevented. Amine transaminases were successfully combined with other enzymes for multi-step synthesis of valuable products: With ketoreductases all four diastereomers of a 1,3-amino alcohol could be obtained, and the use of a lipase allowed for the synthesis of natural products in the form of capsaicinoids. Amine transaminases were also successfully combined with metal catalysts based on palladium or copper. This methodology allowed for the amination of alcohols and the synthesis of chiral amines such as the pharmaceutical compound Rivastigmine. These examples show that the use of amine transaminases in multi-step one-pot reactions is possible, and hopefully this concept can be further developed and applied to make industrial processes more sustainable and efficient in the future.

  • 5.
    Anderson, Mattias
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Afewerki, Samson
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Córdova, Armando
    Chemoenzymatic amination of alcohols by combining oxidation catalysts with transaminases in one potManuscript (preprint) (Other academic)
    Abstract [en]

    Chemoenzymatic methods for the amination of alcohols have been developed. The reactions were performed in a one-pot two-step fashion, where the alcohol starting material was first oxidized to the corresponding carbonyl compound and then subsequently converted to the amine product with an enzymatic system based on an amine transaminase. The enzyme system was able to operate in a water/organic solvent two-phase system in the presence of either a heterogeneous palladium(0) catalyst or a homogeneous copper(I) catalyst. High conversions to the product amines were achieved for a range of substituted benzyl alcohols and similar compounds, but unfortunately the use of aliphatic alcohols resulted in lower conversions and secondary alcohols could not be converted to the corresponding amines with this methodology.

  • 6.
    Anderson, Mattias
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Afewerki, Samson
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cõrdova, Armando
    Total Synthesis of Capsaicin Analogues from Lignin-Derived Compounds by Combined Heterogeneous Metal, Organocatalytic and Enzymatic Cascades in One Pot2014In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 356, no 9, p. 2113-2118Article in journal (Refereed)
    Abstract [en]

    The total synthesis of capsaicin analogues was performed in one pot, starting from compounds that can be derived from lignin. Heterogeneous palladium nanoparticles were used to oxidise alcohols to aldehydes, which were further converted to amines by an enzyme cascade system, including an amine transaminase. It was shown that the palladium catalyst and the enzyme cascade system could be successfully combined in the same pot for conversion of alcohols to amines without any purification of intermediates. The intermediate vanillyl-amine, prepared with the enzyme cascade system, could be further converted to capsaicin analogues without any purification using either fatty acids and a lipase, or Schotten-Baumann conditions, in the same pot. An aldol compound (a simple lignin model) could also be used as starting material for the synthesis of capsaicin analogues. Using l-alanine as organocatalyst, vanillin could be obtained by a retro-aldol reaction. This could be combined with the enzyme cascade system to convert the aldol compound to vanillylamine in a one-step one-pot reaction.

  • 7.
    Axelsson, Karolin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Konstanzer, Vera
    Kuttuva Rajarao, Guna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Terenius, Olle
    Dep of Ecology, SLU.
    Seriot, Lisa
    Nordenhem, Henrik
    Dep. of Ecology, SLU.
    Nordlander, Göran
    Dep. of Ecology, SLU.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Antifeedants produced by bacteria associated to the gut of the pine weevil (Hylobius abietis)Manuscript (preprint) (Other academic)
  • 8.
    Axelsson, Karolin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Biotechnology (BIO).
    Konstanzer, Vera
    KTH.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Terenius, Olle
    Seriot, Lisa
    KTH, School of Biotechnology (BIO).
    Nordenhem, Henrik
    Nordlander, Goran
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Tartu University, Estonia.
    Antifeedants Produced by Bacteria Associated with the Gut of the Pine Weevil Hylobius abietis2017In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 74, no 1, p. 177-184Article in journal (Refereed)
    Abstract [en]

    The pine weevil, Hylobius abietis, is a severe forest pest insect as it feeds on newly planted conifer seedlings. To identify and develop an antifeedant could be one step towards the protection of seedlings from feeding damage by the pine weevil. With the aim to trace the origin of the antifeedants previously found in feces of the pine weevil, we investigated the culturable bacteria associated with the gut and identified the volatiles they produced. Bacterial isolates were identified by 16S ribosomal RNA gene analysis. The volatile emissions of selected bacteria, cultivated on NB media or on the grated phloem of Scots pine twigs dispersed in water, were collected and analyzed by solid-phase microextraction gas chromatography-mass spectrometry. The bacterial isolates released a variety of compounds, among others 2-methoxyphenol, 2-phenylethanol, 3-methyl-1-butanol, 1-octen-3-ol, 3-octanone, dimethyl disulfide, and dimethyl trisulfide. A strong antifeedant effect was observed by 2-phenylethanol, which could thus be a good candidate for use to protect planted conifer seedlings against feeding damage caused by H. abietis.

  • 9.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg-Karlson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Sustainable bio-production of styrene from forest waste2013In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 144, p. 684-688Article in journal (Refereed)
    Abstract [en]

    A strain of Penicillium expansum was studied for the production of styrene using forest waste biomass as a feeding substrate. The fungal strain was cultivated on bark of various trees supplemented with yeast extract and the volatiles produced were collected on Tenax TA and analyzed by gas chromatography-mass spectrometry. Fungus cultured on grated soft bark of pine (Pinus sylvestris) stems (GPB) and mature bark of oak (Quercus robur) supplemented with yeast extract produced relatively the highest amounts of styrene. The maximum styrene production rate was 52.5 mu g/h, 41 mu g/h and 27 mu g/h from fungus cultivated on 50 mL liquid media with 10 g GPB or mature bark of oak and potato dextrose broth respectively. These promising results suggest that the fungal strain could be used to produce "green" styrene plastics using renewable forest waste biomass.

  • 10.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. COMSATS Inst Informat Technol, Dept Chem, Abbottabad 22060, Pakistan.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Terenius, Olle
    Nordlander, Goran
    Nordenhem, Henrik
    Nagahama, Kazuhiro
    Norin, Emil
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg Karlsson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    A fungal metabolite masks the host plant odor for the pine weevil (Hylobius abietis)2015In: Fungal ecology, ISSN 1754-5048, E-ISSN 1878-0083, Vol. 13, p. 103-111Article in journal (Refereed)
    Abstract [en]

    The pine weevil is one of the most important pest insects of conifer reforestation areas in Europe. Female pine weevils cover their eggs with chewed bark and feces (frass) resulting in avoidance behavior of feeding conspecifics towards egg laying sites. It has been suggested that microorganisms present in the frass may be responsible for producing deterrent compounds for the pine weevil. The fungi Ophiostoma canum, O. pluriannulatum, and yeast Debaryomyces hansenii were isolated from aseptically collected pine-weevil frass. The isolated fungi were cultured on weevil frass broth and their volatiles were collected by SPME and identified by GC MS. D. hansenii produced methyl salicylate (MeS) as a major compound, whereas, in addition, O. canum and O. pluriannulatum produced 6-protoilludene. In a multi-choice lab bioassay, MeS strongly reduced pine weevil's attraction to the Pinus sylvestris volatiles. Thus, a fungal metabolite was found that strongly affects the pine weevil host-odor search. (C) 2014 Elsevier Ltd and The British Mycological Society. All rights reserved.

  • 11.
    Azeem, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Department of Chemistry, COMSATS Institute of Information Technology, Abbottabad, Pakistan.
    Terenius, Olle
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Nagahama, Kazuhiro
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Sojo University, Faculty of Biotechnology and Life Science, Department of Applied Microbial Technology, 4-22-1 Ikeda, Nishi-ku, Kumamoto, Japan.
    Nordenhem, Henrik
    Nordlander, Goran
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. Tartu University, Institute of Technology, Division of Organic Chemistry, Tartu, Estonia.
    Chemodiversity and biodiversity of fungi associated with the pine weevil Hylobius abietis2015In: Fungal Biology, ISSN 1878-6146, E-ISSN 1878-6162, Vol. 119, no 8, p. 738-46Article in journal (Refereed)
    Abstract [en]

    The pine weevil Hylobius abietis is a severe pest of conifer seedlings in reforestation areas. Weevils lay eggs in the root bark or in the soil near roots of recently dead trees and cover the eggs with frass (feces combined with chewed bark), possibly to avoid conspecific egg predation. The aim of the present investigation focused on isolation, identification, and volatile production of fungi from pine-weevil feces and frass. Fungi were isolated from weevil frass and feces separately, followed by identification based on ITS sequencing. Fifty-nine isolates belonging to the genera Penicillium, Ophiostoma, Mucor, Leptographium, Eucasphaeria, Rhizosphaera, Debaryomyces, and Candida were identified. Volatile organic compounds (VOCs) produced by the fungal community and fungal isolates cultured on weevil-frass broth were identified by SPME-GCMS. Major VOCs emitted from the fungal community and pure isolates were species- and strain specific and included isopentylalcohol, styrene, 3-octanone, 6-protoilludene, methyl salicylate, 3-methylanisole, 2-methoxyphenol, and phenol. Some of these are known to influence the orientation of pine weevils when tested among highly attractive newly planted conifer seedlings.

  • 12. Bassanini, Ivan
    et al.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. CNR, Italy.
    Riva, Sergio
    Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers2015In: Beilstein Journal of Organic Chemistry, ISSN 2195-951X, E-ISSN 1860-5397, Vol. 11, p. 1583-1595Article, review/survey (Refereed)
    Abstract [en]

    Dicarboxylic acids and their derivatives (esters and anhydrides) have been used as acylating agents in lipase-catalyzed reactions in organic solvents. The synthetic outcomes have been dimeric or hybrid derivatives of bioactive natural compounds as well as functionalized polyesters.

  • 13. Bayat, N.
    et al.
    Lopes, V. R.
    Sanchez-Dominguez, M.
    Lakshmanan, Ramnath
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cristobal, S.
    Assessment of functionalized iron oxide nanoparticles in vitro: introduction to integrated nanoimpact index2015In: Environmental Science: Nano, ISSN 2051-8153, Vol. 2, no 4, p. 380-394Article in journal (Refereed)
    Abstract [en]

    Functionalization of super paramagnetic iron oxide NPs (SPIONs) with different coatings renders them with unique physicochemical properties that allow them to be used in a broad range of applications such as drug targeting and water purification. However, it is required to fill the gap between the promises of any new functionalized SPIONs and the effects of these coatings on the NPs safety. Nanotoxicology is offering diverse strategies to assess the effect of exposure to SPIONs in a case-by-case manner but an integrated nanoimpact scale has not been developed yet. We have implemented the classical integrated biological response (IBR) into an integrated nanoimpact index (INI) as an early warning scale of nano-impact based on a combination of toxicological end points such as cell proliferation, oxidative stress, apoptosis and genotoxicity. Here, the effect of SPIONs functionalized with tri-sodium citrate (TSC), polyethylenimine (PEI), aminopropyl-triethoxysilane (APTES) and Chitosan (chitosan) were assessed on human keratinocytes and endothelial cells. Our results show that endothelial cells were more sensitive to exposure than keratinocytes and the initial cell culture density modulated the toxicity. PEI-SPIONs had the strongest effects in both cell types while TSC-SPIONS were the most biocompatible. This study emphasizes not only the importance of surface coatings but also the cell type and the initial cell density on the selection of toxicity assays. The INI developed here could offer an initial rationale to choose either modifying SPIONs properties to reduce its nanoimpact or performing a complete risk assessment to define the risk boundaries.

  • 14. Beatriz Badia, Mariana
    et al.
    Mans, Robert
    Lis, Alicia V.
    Ariel Tronconi, Marcos
    Lucia Arias, Cintia
    Maurino, Veronica Graciela
    Santiago Andreo, Carlos
    Fabiana Drincovich, Maria
    van Maris, Antonius J. A.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Gerrard Wheeler, Mariel Claudia
    Specific Arabidopsis thaliana malic enzyme isoforms can provide anaplerotic pyruvate carboxylation function in Saccharomyces cerevisiae2017In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 284, no 4, p. 654-665Article in journal (Refereed)
    Abstract [en]

    NAD(P)-malic enzyme (NAD(P)-ME) catalyzes the reversible oxidative decarboxylation of malate to pyruvate, CO2, and NAD(P)H and is present as a multigene family in Arabidopsis thaliana. The carboxylation reaction catalyzed by purified recombinant Arabidopsis NADP-ME proteins is faster than those reported for other animal or plant isoforms. In contrast, no carboxylation activity could be detected in vitro for the NAD-dependent counterparts. In order to further investigate their putative carboxylating role in vivo, Arabidopsis NAD(P)-ME isoforms, as well as the NADP-ME2del2 (with a decreased ability to carboxylate pyruvate) and NADP-ME2R115A (lacking fumarate activation) versions, were functionally expressed in the cytosol of pyruvate carboxylase-negative (Pyc(-)) Saccharomyces cerevisiae strains. The heterologous expression of NADP-ME1, NADP-ME2 (and its mutant proteins), and NADP-ME3 restored the growth of Pyc(-) S. cerevisiae on glucose, and this capacity was dependent on the availability of CO2. On the other hand, NADP-ME4, NAD-ME1, and NAD-ME2 could not rescue the Pyc(-) strains from C-4 auxotrophy. NADP-ME carboxylation activity could be measured in leaf crude extracts of knockout and over-expressing Arabidopsis lines with modified levels of NADP-ME, where this activity was correlated with the amount of NADP-ME2 transcript. These results indicate that specific A. thaliana NADP-ME isoforms are able to play an anaplerotic role in vivo and provide a basis for the study on the carboxylating activity of NADP-ME, which may contribute to the synthesis of C-4 compounds and redox shuttling in plant cells.

  • 15. Beijer, K.
    et al.
    Björlenius, Berndt
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Shaik, S.
    Lindberg, R. H.
    Brunström, B.
    Brandt, I.
    Removal of pharmaceuticals and unspecified contaminants in sewage treatment effluents by activated carbon filtration and ozonation: Evaluation using biomarker responses and chemical analysis2017In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 176, p. 342-351Article in journal (Refereed)
    Abstract [en]

    Traces of active pharmaceutical ingredients (APIs) and other chemicals are demonstrated in effluents from sewage treatment plants (STPs) and they may affect quality of surface water and eventually drinking water. Treatment of effluents with granular activated carbon (GAC) or ozone to improve removal of APIs and other contaminants was evaluated at two Swedish STPs, Käppala and Uppsala (88 and 103 APIs analyzed). Biomarker responses in rainbow trout exposed to regular and additionally treated effluents were determined. GAC and ozone treatment removed 87–95% of the total concentrations of APIs detected. In Käppala, GAC removed 20 and ozonation (7 g O3/m3) 21 of 24 APIs detected in regular effluent. In Uppsala, GAC removed 25 and ozonation (5.4 g O3/m3) 15 of 25 APIs detected in effluent. GAC and ozonation also reduced biomarker responses caused by unidentified pollutants in STP effluent water. Elevated ethoxyresorufin-O-deethylase (EROD) activity in gills was observed in fish exposed to effluent in both STPs. Gene expression analysis carried out in Käppala showed increased concentrations of cytochrome P450 (CYP1As and CYP1C3) transcripts in gills and of CYP1As in liver of fish exposed to effluent. In fish exposed to GAC- or ozone-treated effluent water, gill EROD activity and expression of CYP1As and CYP1C3 in gills and liver were generally equal to or below levels in fish held in tap water. The joint application of chemical analysis and sensitive biomarkers proved useful for evaluating contaminant removal in STPs with new technologies.

  • 16. Bengtsson-Palme, Johan
    et al.
    Hammaren, Rickard
    Pal, Chandan
    Ostman, Marcus
    Björlenius, Berndt
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Flach, Carl-Fredrik
    Fick, Jerker
    Kristiansson, Erik
    Tysklind, Mats
    Larsson, D. G. Joakim
    Elucidating selection processes for antibiotic resisitance in sewage treatment plants using metagenomics2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 572, p. 697-712Article in journal (Refereed)
    Abstract [en]

    Sewage treatment plants (STPs) have repeatedly been suggested as hotspots for the emergence and dissemination of antibiotic-resistant bacteria. A critical question still unanswered is if selection pressures within STPs, caused by residual antibiotics or other co-selective agents, are sufficient to specifically promote resistance. To address this, we employed shotgun metagenomic sequencing of samples from different steps of the treatment process in three Swedish STPs. In parallel, concentrations of selected antibiotics, biocides and metals were analyzed. We found that concentrations of tetracycline and ciprofloxacin in the influent were above predicted concentrations for resistance selection, however, there was no consistent enrichment of resistance genes to any particular class of antibiotics in the STPs, neither for biocide and metal resistance genes. The most substantial change of the bacterial communities compared to human feces occurred already in the sewage pipes, manifested by a strong shift from obligate to facultative anaerobes. Through the treatment process, resistance genes against antibiotics, biocides and metals were not reduced to the same extent as fecal bacteria. The OXA-48 gene was consistently enriched in surplus and digested sludge. We find this worrying as OXA-48, still rare in Swedish clinical isolates, provides resistance to carbapenems, one of our most critically important classes of antibiotics. Taken together, metagenomics analyses did not provide clear support for specific antibiotic resistance selection. However, stronger selective forces affecting gross taxonomic composition, and with that resistance gene abundances, limit interpretability. Comprehensive analyses of resistant/non-resistant strains within relevant species are therefore warranted. 

  • 17.
    Berglund, Per
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Hedenstrom, E
    Hult, K
    Controlling lipase enantioselectivity for organic synthesis2000In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 219, no 1, p. U219-U219Article in journal (Refereed)
  • 18.
    Berglund, Torkel
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Lindström, Anders
    Aghelpasand, Hooman
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Stattin, Eva
    Ohlsson, Anna B.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Protection of spruce seedlings against pine weevil attacks by treatment of seeds or seedlings with nicotinamide, nicotinic acid and jasmonic acid2016In: Forestry (London), ISSN 0015-752X, E-ISSN 1464-3626, Vol. 89, no 2, p. 127-135Article in journal (Refereed)
    Abstract [en]

    Sustainable methods are required to protect newly planted tree seedlings from insect herbivore attack. To this end, here Norway spruce (Picea abies (L.) Karst.) seeds were treated with 2.5 mM nicotinamide (NIC), 2.5 mM nicotinic acid (NIA), 3 mM jasmonic acid (JA) or 0.2 mM 5-azacytidine (5-Aza), and 6-month-old seedlings grown from these seeds were planted at a reforestation area in central Sweden. Attack by pine weevils (Hylobius abietis) was reduced by 50 per cent by NIC treatment, 62.5 per cent by JA treatment and 25 per cent by 5-Aza treatment, when compared with seedlings grown from untreated seeds. Watering 18-month-old spruce seedlings with 2 mM NIC or 2 mM NIA did reduce attack during the first season in the field by 40 and 53 per cent, respectively, compared with untreated plants. Girdling was also reduced by the different treatments. Analysis of conifer seedlings treated with 5-Aza points at a possible involvement of epigenetic mechanisms in this defensive capacity. This is supported by a reduced level of DNA methylation in the needles of young spruce seedlings grown in a greenhouse from NIC-treated seeds. Seed treatment for seedling defense potentiation is simple, inexpensive and also a new approach for forestry with many potential applications.

  • 19.
    Berglund, Torkel
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Wallström, A.
    Nguyen, T. -V
    Laurell, Cecilia
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Ohlsson, Anna B.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Nicotinamide; antioxidative and DNA hypomethylation effects in plant cells2017In: Plant physiology and biochemistry (Paris), ISSN 0981-9428, E-ISSN 1873-2690, Vol. 118, p. 551-560Article in journal (Refereed)
    Abstract [en]

    The effects of nicotinamide (NIC) and its natural plant metabolites nicotinic acid (NIA) and trigonelline (TRIG) were studied with respect to defense in plant cell cultures. NIC and NIA could protect against oxidative stress damage caused by 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH), which generates free radicals. Damage was analyzed as DNA strand breaks in cell cultures of Pisum sativum (garden pea), Daucus carota (carrot), Populus tremula L. × P. tremuloides (hybrid aspen) and Catharanthus roseus (Madagascar periwinkle), monitored by single cell gel electrophoresis (comet assay), and assays of cell leakage in C. roseus. The activities of aconitase and fumarase enzymes, which have key roles in energy metabolism, were analyzed in P. sativum cultures after treatment with NIC or NIA. Aconitase activity was increased by NIA, and fumarase activity was increased by both compounds. These compounds were shown to promote glutathione metabolism in P. sativum cultures, and NIC was shown to have a global DNA hypomethylating effect. Neither TRIG nor poly(ADP-ribose) polymerase (PARP) inhibitor 3-aminobenzamide offered any protection against DNA damage or cell leakage, nor did they promote aconitase or fumarase activities, or glutathione metabolism. By this broad approach addressing multiple biochemical factors and different plant species, we demonstrate that NIC and NIA protect plant cells from oxidative stress, and that NIC clearly exerts an epigenetic effect; decreased DNA methylation. This indicates that these compounds have important roles in the regulation of metabolism in plant cells, especially in connection to stress.

  • 20.
    Bodlund, Ida
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Coagulant Protein from plant materials: Potential Water Treatment Agent2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Access to fresh water is a human right, yet more than 780 million people, especially in rural areas, rely on unimproved sources and the need for finding ways of treating water is crucial. Although the use of natural coagulant protein in drinking water treatment has been discussed for a long time, the method is still not in practice, probably due to availability of material and limited knowledge. In this study, about hundred different crude extracts made from plant materials found in Southern India were screened for coagulation activity. Extracts of three Brassica species (Mustard, Cabbage and Cauliflower) were showing activity comparable to that of Moringa oleifera and were further investigated. Their protein content and profile were compared against each other and with coagulant protein from Moringa. Mustard (large) and Moringa seed proteins were also studied for their effect against clinically isolated bacterial strains. The protein profiles of Brassica extract showed predominant bands around 9kDa and 6.5kDa by SDS-PAGE. The peptide sequence analysis of Mustard large identified the 6.5kDa protein as Moringa coagulant protein (MO2.1) and the 9kDa protein band as seed storage protein napin3. Of thirteen clinical strains analysed, Moringa and Mustard large were proven effective in either aggregation activity or growth kinetic method or both in all thirteen and nine strains respectively. To my knowledge this is the first report on the presence of coagulant protein in Brassica seeds. Owing to the promising results Brassica species could possibly be used as a substitute to Moringa coagulating agent and chemicals in drinking water treatment. 

  • 21.
    Bodlund, Ida
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Pavankumar, Asalapuram Ramachand
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Chelliah, R.
    Anna University, Chennai.
    Kasi, S.
    Anna University, Chennai.
    Sankaran, K.
    Anna University, Chennai.
    Kuttuva Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Coagulant proteins identified in Mustard: a potential water treatment agent2014In: International Journal of Environmental Science and Technology, ISSN 1735-1472, E-ISSN 1735-2630, Vol. 11, no 4, p. 873-880Article in journal (Refereed)
    Abstract [en]

    The use of natural coagulant protein in drinking water treatment has been discussed for a long time, though the method is still not in practice, probably due to limited knowledge and availability of material. In the present work, different Mustard varieties were tested for the presence of coagulant protein compared with Moringa seed extract and their potential application in water treatment. The coagulation activity of the protein extract was measured using synthetic clay solution as well as water from pond. The protein content was determined by Bradford method, molecular mass determined by Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and peptide sequence was analyzed by Mass spectrometry. Extract of Mustard (large) and Moringa seed showed coagulation activity of a parts per thousand...70 and a parts per thousand...85 % after 90 min, respectively. Interestingly, seed extracts from other Mustard varieties had coagulation activity after heat activation at 95 A degrees C for 5 h. However, the coagulation activity of Mustard seed extract against turbid pond water was higher (a parts per thousand...60 %) compared to Moringa seed extract (a parts per thousand...50 %). The peptide sequence analysis of 6.5 and 9 kDa proteins was found to be homologous to Moringa coagulant protein and napin3, respectively. To our knowledge, this could be the first report on Mustard seed having coagulant protein. The coagulation activity of Mustard (large) against highly turbid pond water suggested that it could be a potential natural coagulant for water treatment.

  • 22.
    Bodlund, Ida
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Sabarigrisan, K.
    Chelliah, R.
    Sankaran, K.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Screening of coagulant proteins from plant material in southern India2013In: Water Science and Technology: Water Supply, ISSN 1606-9749, E-ISSN 1607-0798, Vol. 13, no 6, p. 1478-1485Article in journal (Refereed)
    Abstract [en]

    Access to fresh water is limited due to the growing population and to provide safe drinking water is a global challenge. In this initial study, about a hundred different samples were screened for coagulation activity. Amongst the plants tested were fruits and vegetable pulps, leaves and seeds (like jackfruit, tamarind, papaya, orange, watermelon, pineapple, cucumber, green gram, peas, black gram, cluster bean rice, maize, chili, cabbage, mustard, cauliflower, beetroot and carrot). The crude extracts were prepared in water and salt solution in order to extract the coagulant protein and compare the coagulation activity. Among the tested samples, only a few seed extracts showed coagulation activity. The seed extracts of mustard and cabbage showed coagulation activity in both water and salt extracts and were comparable to that of Moringa seed extract. The salt extracts showed higher activity compared to that of water extract in most of the samples tested. The coagulation activity was stable after incubation at 95 WC for 5 hours implying heat resistance. A protein profile analysis showed major protein bands with a molecular weight around 6.5 and 9 kDa. In this preliminary study, mustard and cabbage seed extracts were promising in terms of coagulation and heat resistance, so could be an alternative to Moringa seed for water treatment and should be investigated further.

  • 23. Bollhoner, Benjamin
    et al.
    Jokipii-Lukkari, Soile
    Bygdell, Joakim
    Stael, Simon
    Adriasola, Mathilda
    KTH, School of Biotechnology (BIO).
    Muniz, Luis
    Van Breusegem, Frank
    Ezcurra, Ines
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Wingsle, Gunnar
    Tuominen, Hannele
    The function of two type II metacaspases in woody tissues of Populus trees2018In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 217, no 4, p. 1551-1565Article in journal (Refereed)
    Abstract [en]

    Metacaspases (MCs) are cysteine proteases that are implicated in programmed cell death of plants. AtMC9 (Arabidopsis thaliana Metacaspase9) is a member of the Arabidopsis MC family that controls the rapid autolysis of the xylem vessel elements, but its downstream targets in xylem remain uncharacterized. PttMC13 and PttMC14 were identified as AtMC9 homologs in hybrid aspen (Populustremulaxtremuloides). A proteomic analysis was conducted in xylem tissues of transgenic hybrid aspen trees which carried either an overexpression or an RNA interference construct for PttMC13 and PttMC14. The proteomic analysis revealed modulation of levels of both previously known targets of metacaspases, such as Tudor staphylococcal nuclease, heat shock proteins and 14-3-3 proteins, as well as novel proteins, such as homologs of the PUTATIVE ASPARTIC PROTEASE3 (PASPA3) and the cysteine protease RD21 by PttMC13 and PttMC14. We identified here the pathways and processes that are modulated by PttMC13 and PttMC14 in xylem tissues. In particular, the results indicate involvement of PttMC13 and/or PttMC14 in downstream proteolytic processes and cell death of xylem elements. This work provides a valuable reference dataset on xylem-specific metacaspase functions for future functional and biochemical analyses.

  • 24. Bracher, J. M.
    et al.
    de Hulster, E.
    Koster, C. C.
    van den Broek, M.
    Daran, J. -MG.
    van Maris, Antonius J.A.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. Delft University of Technology, Netherlands.
    Pronk, J. T.
    Laboratory evolution of a biotin-requiring Saccharomyces cerevisiae strain for full biotin prototrophy and identification of causal mutations2017In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 83, no 16, article id e00892-17Article in journal (Refereed)
    Abstract [en]

    Biotin prototrophy is a rare, incompletely understood, and industrially relevant characteristic of Saccharomyces cerevisiae strains. The genome of the haploid laboratory strain CEN.PK113-7D contains a full complement of biotin biosynthesis genes, but its growth in biotin-free synthetic medium is extremely slow (specific growth rate [μ] ≈ 0.01 h-1). Four independent evolution experiments in repeated batch cultures and accelerostats yielded strains whose growth rates (μ ≤ 0.36 h-1) in biotin-free and biotin-supplemented media were similar. Whole-genome resequencing of these evolved strains revealed up to 40-fold amplification of BIO1, which encodes pimeloyl-coenzyme A (CoA) synthetase. The additional copies of BIO1 were found on different chromosomes, and its amplification coincided with substantial chromosomal rearrangements. A key role of this gene amplification was confirmed by overexpression of BIO1 in strain CEN.PK113-7D, which enabled growth in biotin-free medium (μ= 0.15 h-1). Mutations in the membrane transporter genes TPO1 and/or PDR12 were found in several of the evolved strains. Deletion of TPO1 and PDR12 in a BIO1-overexpressing strain increased its specific growth rate to 0.25 h-1. The effects of null mutations in these genes, which have not been previously associated with biotin metabolism, were nonadditive. This study demonstrates that S. cerevisiae strains that carry the basic genetic information for biotin synthesis can be evolved for full biotin prototrophy and identifies new targets for engineering biotin prototrophy into laboratory and industrial strains of this yeast.

  • 25. Cassimjee, Karim Engelmark
    et al.
    Hendil-Forssell, Peter
    Volkov, Alexey
    Krog, Anne
    Malmo, Jostein
    Aune, Trond Erik V.
    Knecht, Wolfgang
    Miskelly, Iain R.
    Moody, Thomas S.
    Humble, Maria Svedendahl
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Streamlined Preparation of Immobilized Candida antarctica Lipase B2017In: ACS OMEGA, ISSN 2470-1343, Vol. 2, no 12, p. 8674-8677Article in journal (Refereed)
    Abstract [en]

    Candida antarctica lipase B (CalB) was efficiently expressed (6.2 g L-1) in Escherichia coli by utilizing an N-terminal tag cassette and the XylS/Pm expression system in a fed-batch bioreactor; subsequent direct binding to EziG from crude extracts resulted in an immobilized catalyst with superior activity to Novozym 435.

  • 26. Castan, Andreas
    et al.
    Fäldt, Erik
    Mölleryd, Carin
    Lindskog, Eva
    Chotteau, Veronique
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cultivation process intensification utilizing a WAVE Bioreactor (TM) for perfusion cell cultures2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245Article in journal (Other academic)
  • 27.
    Chen, Shan
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Svedendahl Humble, Maria
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Stabilization of an amine transaminase for biocatalysis2016In: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, E-ISSN 1873-3158, Vol. 124, p. 20-28Article in journal (Refereed)
    Abstract [en]

    The amine transaminase from Chromobacterium violaceum (Cv-ATA) is a well-known enzyme to achievechiral amines of high enantiomeric excess in laboratory scales. However, the low operational stabilityof Cv-ATA limits the enzyme applicability on larger scales. In order to improve the operational stabilityof Cv-ATA, and thereby extending its applicability, factors (additives, co-solvents, organic solvents anddifferent temperatures) targeting enzyme stability and activity were explored in order to find out how tostore and apply the enzyme. The present investigation shows that the melting point of Cv-ATA is improvedby adding sucrose or glycerol, separately. Further, by storing the enzyme at higher concentrations and inco-solvents, such as; 50% glycerol, 20% methanol or 10% DMSO, the active dimeric structure of Cv-ATAis retained. Enzyme stored in 50% glycerol at −20◦C was e.g., still fully active after 6 months. Finally,the enzyme performance was improved 5-fold by a co-lyophilization with surfactants prior to usage inisooctane.

  • 28.
    Chen, Shan
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. Hainan University, China.
    Liu, Fuyan
    Zhang, Kuan
    Huang, Hansheng
    Wang, Huani
    Zhou, Jiaying
    Zhang, Jing
    Gong, Yiwei
    Zhang, Dela
    Chen, Yiping
    Lin, Chang
    Wang, Bo
    An efficient enzymatic aminolysis for kinetic resolution of aromatic alpha-hydroxyl acid in non-aqueous media2016In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 57, no 48, p. 5312-5314Article in journal (Refereed)
    Abstract [en]

    A new and highly efficient enzymatic aminolysis approach for kinetic resolution of aromatic a-hydroxy acid in non-aqueous media has been developed. The corresponding alpha-hydroxyl acid ester was employed as the substrate, and commercially available Candida antarctica lipase B is used as the biocatalyst, anhydrous ammonia is the resolving agent. Reactions can be proceeded smoothly in organic solvent at ambient temperatures. High concentration of substrate is allowed due to the application of organic media and the products are obtained in yields of up to 49% with ee values of up to 99%, and with E value of >300, representing an appealing and promising protocol for large-scale preparations.

  • 29.
    Chen, Zhi-Hui
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Taiyuan University of Technology, China; Beijing University of Posts and Telecommunications, China .
    Wang, Yang
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Yang, Yibiao
    Qiao, Na
    Wang, Yuncai
    Yu, Zhongyuan
    Enhanced normal-direction excitation and emission of dual-emitting quantum dots on a cascaded photonic crystal surface2014In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 6, no 24, p. 14708-14715Article in journal (Refereed)
    Abstract [en]

    Large normal-direction excitation and emission of dual-emitting quantum dots (QDs) are essential for practical application of QD sensors based on the ratiometric fluorescence response. We have numerically demonstrated an all-dielectric four-layer cascaded photonic crystal (CPC) structure (alternating TiO2 and SiO2/SU8 layers with two dimensional nanoscale patterns in each layer) which is capable of providing normal-direction high Q-factor leaky modes at excitation wavelengths of QDs and two low Q-factor leaky modes coinciding with the two emission peaks of a dual-emitting QD. Normal-direction excitation and far-field emission of the dual-emitting QDs are enhanced significantly when QDs are distributed on/in the top TiO2 layer of the CPC structure, especially in the spatial distribution areas of the resonant leaky modes. QDs can be positioned differently depending on the applications. Positioning QDs on the top TiO2 layer will improve the signal-to-noise ratios of QD biomedical/chemical/temperature sensors, while embedding QDs in the top TiO2 layer will increase the light extraction from the QD light emitting device, making our CPC a versatile optical coupling structure. Our CPC-QD structure is experimentally feasible and robust against the parameter perturbation in real fabrication.

  • 30.
    Chotteau, Veronique
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Perfusion Processes2015In: Animal Cell Culture / [ed] Mohamed Al-Rubeai, Switzerland Springer: Springer , 2015, p. 407-443Chapter in book (Refereed)
    Abstract [en]

    The interest for perfusion is increasing nowadays. This new focus has emerged from a synergy of a demand for disposable equipment and the availability of robust cell separation device, as well as the need for higher flexibility and lower investment cost. The cell separation devices mostly used today are based on filtration, i.e. alternating flow filtration, tangential flow filtration, spin-filter, or acceleration/gravity, i.e. inclined settler, centrifuge, acoustic settler. This paper gives an introduction to the basic concepts of perfusion and its practical implementation. It reviews the actual cell separation devices and describes the approaches used in the field to develop and optimize the perfusion processes.

  • 31.
    Chotteau, Veronique
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Diana, Rafael
    Ge Healthcare Bio-sciences Ab.
    Kaisermayer, Christian
    Ge Healthcare Bio-sciences Ab.
    Lindskog, Eva
    Ge Healthcare Bio-sciences Ab.
    Robinson, Craig
    Ge Healthcare Bio-sciences Ab.
    Rucker, Jimmie L.
    Ge Healthcare Bio-sciences Ab.
    Walsh, Kieron D.
    Ge Healthcare Bio-sciences Ab.
    Flexible bag for cultivation of cells2011Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    An inflatable bioreactor bag for cell cultivation, which comprising a top and a bottom sheet of flexible material, joined together to form two end edges and two side edges, wherein one baffle or a plurality of baffles extend from the bottom sheet in a region where the shortest distance to any one of the two end edges is higher than about one fourth of the shortest distance between the two end edges.

  • 32.
    Chotteau, Veronique
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Zhang, Ye
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Clincke, Marie-Francoise
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Very High Cell Density in Perfusion of CHO Cells by ATF, TFF, Wave Bioreactor, and/or CellTank Technologies: Impact of Cell Density and Applications2014In: Continuous Processing in Pharmaceutical Manufacturing / [ed] Ganapathy Subramanian, Germany Weinheim: Wiley-VCH Verlagsgesellschaft, 2014, p. 339-356Chapter in book (Other academic)
  • 33.
    Chung, Hannah
    et al.
    Korean Adanced Institute of Science and Technology (KAIST).
    Yang, Jung Eun
    Korean Adanced Institute of Science and Technology (KAIST).
    Ha, Ji Yeon
    Korean Adanced Institute of Science and Technology (KAIST).
    Chae, Tong Un
    Korean Adanced Institute of Science and Technology (KAIST).
    Shin, Jae Ho
    Korean Adanced Institute of Science and Technology (KAIST).
    Gustavsson, Martin
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Lee, Sang Yup
    Korean Adanced Institute of Science and Technology (KAIST).
    Bio-based production of monomers and polymers by metabolically engineered microorganisms2015In: Current Opinion in Biotechnology, ISSN 0958-1669, E-ISSN 1879-0429, Vol. 36, p. 73-84Article, review/survey (Refereed)
    Abstract [en]

    Recent metabolic engineering strategies for bio-based production of monomers and polymers are reviewed. In the case of monomers, we describe strategies for producing polyamide precursors, namely diamines (putrescine, cadaverine, 1,6-diaminohexane), dicarboxylic acids (succinic, glutaric, adipic, and sebacic acids), and ω-amino acids (γ-aminobutyric, 5-aminovaleric, and 6-aminocaproic acids). Also, strategies for producing diols (monoethylene glycol, 1,3-propanediol, and 1,4-butanediol) and hydroxy acids (3-hydroxypropionic and 4-hydroxybutyric acids) used for polyesters are reviewed. Furthermore, we review strategies for producing aromatic monomers, including styrene, p-hydroxystyrene, p-hydroxybenzoic acid, and phenol, and propose pathways to aromatic polyurethane precursors. Finally, in vivo production of polyhydroxyalkanoates and recombinant structural proteins having interesting applications are showcased.

  • 34. Cueto-Rojas, Hugo F.
    et al.
    Milne, Nicholas
    van Helmond, Ward
    Pieterse, Mervin M.
    van Maris, Antonius J. A.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Daran, Jean-Marc
    Wahl, S. Aljoscha
    Membrane potential independent transport of NH3 in the absence of ammonium permeases in Saccharomyces cerevisiae2017In: BMC Systems Biology, ISSN 1752-0509, E-ISSN 1752-0509, Vol. 11, article id 49Article in journal (Refereed)
    Abstract [en]

    Background: Microbial production of nitrogen containing compounds requires a high uptake flux and assimilation of the N-source (commonly ammonium), which is generally coupled with ATP consumption and negatively influences the product yield. In the industrial workhorse Saccharomyces cerevisiae, ammonium (NH4+) uptake is facilitated by ammonium permeases (Mep1, Mep2 and Mep3), which transport the NH4+ ion, resulting in ATP expenditure to maintain the intracellular charge balance and pH by proton export using the plasma membrane-bound H+ -ATPase. Results: To decrease the ATP costs for nitrogen assimilation, the Mep genes were removed, resulting in a strain unable to uptake the NH4+ ion. Subsequent analysis revealed that growth of this Delta mep strain was dependent on the extracellular NH3 concentrations. Metabolomic analysis revealed a significantly higher intracellular NHX concentration (3.3-fold) in the Delta mep strain than in the reference strain. Further proteomic analysis revealed significant up-regulation of vacuolar proteases and genes involved in various stress responses. Conclusions: Our results suggest that the uncharged species, NH3, is able to diffuse into the cell. The measured intracellular/extracellular NHX ratios under aerobic nitrogen-limiting conditions were consistent with this hypothesis when NHx compartmentalization was considered. On the other hand, proteomic analysis indicated a more pronounced N-starvation stress response in the Delta mep strain than in the reference strain, which suggests that the lower biomass yield of the Delta mep strain was related to higher turnover rates of biomass components.

  • 35. Córdova, Armando
    et al.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Anderson, Mattias
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Afewerki, Samson
    Efficient Synthesis Of Amines And Amides From Alcohols And Aldehydes By Using Cascade Catalysis2015Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    The present invention relates generally to an eco-friendly methodology for the conversion of alcohols and aldehydes to amines and amides using an integrated enzyme cascade system with metal-and organocatalysis. More specifically, the present invention relates to synthesis of capsaicinoids starting from vanillin alcohol and using a combination of an enzyme cascade system and catalysts. Furthermore, the method also relates to synthesis of capsaicinoids derivatives starting from vanillin alcohol derivatives and using a combination of an enzyme cascade system and catalysts.

  • 36. Dabrowska, B.B.
    et al.
    Vithanage, M.
    Gunaratna, Kuttuva Rajarao
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Mukherjee, A.B.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Bioremediation of arsenic in contaminated terrestrial and aquatic environments2012In: Environmental Chemistry for a Sustainable World, Springer Netherlands , 2012, Vol. 2, p. 475-509Chapter in book (Other academic)
    Abstract [en]

    The name Arsenic is derived from the Greek word arsenikon, meaning potent. This element occurs in the ecosystem in different oxidation states of which As(III) and As(V) are most common to humans, animals, plant species. As is present in drinking water and soil from natural sources as well as a pollutant from agricultural and industrial processes. Differences in arsenic uptake by different plant species is controlled by many factors such as root surface area, root exudates, and rate of evapotranspiration. Some plant species have high affinity to accumulate arsenic in tissues above ground. Hyperaccumulator plants have a threshold arsenic content above 1,000 μg g-1 DM. We review bioremediation studies with especial emphasis on biosorption research on different arsenic species, plants and their biomass, agricultural and industry wastes, as well as the biomass of some fungi species. Bioremediation is considered as an alternative technique for the removal of As in groundwater. One of the popular methods among bioremediation techniques, phytoremediation uses living plants to remove arsenic from the environment or to render it less toxic, in bioaccumulation processes. Phytoremediation techniques often do not take into account the biosorption processes of living plants and plant litter. In biosorption techniques, contaminants can be removed by a biological substrate as a sorbent such as bacteria, fungi, algae or vascular plants. Bioremediation assures in situ treatment of polluted soils. Biosorption characteristics, equilibrium and kinetics of different biosorbents have also been addressed here. Evaluation of the current literature suggests that arsenic bioavailability and molecular level phytoremediation processes in bioremediation are crucial for designing phytoremediation technologies with improved, predictable remedial success.

  • 37. Dalman, Kerstin
    et al.
    Wind, Julia Johanna
    KTH, School of Biotechnology (BIO).
    Nemesio-Gorriz, Miguel
    Hammerbacher, Almuth
    Lunden, Karl
    Ezcurra, Ines
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Elfstrand, Malin
    Overexpression of PaNAC03, a stress induced NAC gene family transcription factor in Norway spruce leads to reduced flavonol biosynthesis and aberrant embryo development2017In: BMC Plant Biology, ISSN 1471-2229, E-ISSN 1471-2229, Vol. 17, article id 6Article in journal (Refereed)
    Abstract [en]

    Background: The NAC family of transcription factors is one of the largest gene families of transcription factors in plants and the conifer NAC gene family is at least as large, or possibly larger, as in Arabidopsis. These transcription factors control both developmental and stress induced processes in plants. Yet, conifer NACs controlling stress induced processes has received relatively little attention. This study investigates NAC family transcription factors involved in the responses to the pathogen Heterobasidion annosum (Fr.) Bref. sensu lato. Results: The phylogeny and domain structure in the NAC proteins can be used to organize functional specificities, several well characterized stress-related NAC proteins are found in III-3 in Arabidopsis (Jensen et al. Biochem J 426: 183-196, 2010). The Norway spruce genome contain seven genes with similarity to subgroup III-3 NACs. Based on the expression pattern PaNAC03 was selected for detailed analyses. Norway spruce lines overexpressing PaNAC03 exhibited aberrant embryo development in response to maturation initiation and 482 misregulated genes were identified in proliferating cultures. Three key genes in the flavonoid biosynthesis pathway: a CHS, a F3'H and PaLAR3 were consistently down regulated in the overexpression lines. In accordance, the overexpression lines showed reduced levels of specific flavonoids, suggesting that PaNAC03 act as a repressor of this pathway, possibly by directly interacting with the promoter of the repressed genes. However, transactivation studies of PaNAC03 and PaLAR3 in Nicotiana benthamiana showed that PaNAC03 activated PaLAR3A, suggesting that PaNAC03 does not act as an independent negative regulator of flavan-3-ol production through direct interaction with the target flavonoid biosynthetic genes. Conclusions: PaNAC03 and its orthologs form a sister group to well characterized stress-related angiosperm NAC genes and at least PaNAC03 is responsive to biotic stress and appear to act in the control of defence associated secondary metabolite production.

  • 38. Derba-Maceluch, Marta
    et al.
    Awano, Tatsuya
    Takahashi, Junko
    Lucenius, Jessica
    Ratke, Christine
    Kontro, Inkeri
    Busse-Wicher, Marta
    Kosik, Ondrej
    Tanaka, Ryo
    Winzell, Anders
    KTH, School of Biotechnology (BIO), Glycoscience.
    Kallas, Åsa
    KTH, School of Biotechnology (BIO), Glycoscience.
    Lesniewska, Joanna
    Berthold, Fredrik
    Immerzeel, Peter
    Teeri, Tuula T.
    KTH, School of Biotechnology (BIO), Glycoscience.
    Ezcurra, Ines
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Dupree, Paul
    Serimaa, Ritva
    Mellerowicz, Ewa J.
    Suppression of xylan endotransglycosylase PtxtXyn10A affects cellulose microfibril angle in secondary wall in aspen wood2015In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 205, no 2, p. 666-681Article in journal (Refereed)
    Abstract [en]

    Certain xylanases from family GH10 are highly expressed during secondary wall deposition, but their function is unknown. We carried out functional analyses of the secondary-wall specific PtxtXyn10A in hybrid aspen (Populus tremulaxtremuloides).PtxtXyn10A function was analysed by expression studies, overexpression in Arabidopsis protoplasts and by downregulation in aspen.PtxtXyn10A overexpression in Arabidopsis protoplasts resulted in increased xylan endotransglycosylation rather than hydrolysis. In aspen, the enzyme was found to be proteolytically processed to a 68kDa peptide and residing in cell walls. Its downregulation resulted in a corresponding decrease in xylan endotransglycosylase activity and no change in xylanase activity. This did not alter xylan molecular weight or its branching pattern but affected the cellulose-microfibril angle in wood fibres, increased primary growth (stem elongation, leaf formation and enlargement) and reduced the tendency to form tension wood. Transcriptomes of transgenic plants showed downregulation of tension wood related genes and changes in stress-responsive genes. The data indicate that PtxtXyn10A acts as a xylan endotransglycosylase and its main function is to release tensional stresses arising during secondary wall deposition. Furthermore, they suggest that regulation of stresses in secondary walls plays a vital role in plant development.

  • 39.
    Divne, Christina
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    SINNING, I
    STAHLBERG, J
    PETTERSSON, G
    BAILEY, M
    SIIKAAHO, M
    MARGOLLESCLARK, E
    TEERI, T
    JONES, TA
    CRYSTALLIZATION AND PRELIMINARY-X-RAY STUDIES ON THE CORE PROTEINS OF CELLOBIOHYDROLASE-I AND ENDOGLUCANASE-I FROM TRICHODERMA-REESEI1993In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 234, no 3, p. 905-907Article in journal (Refereed)
  • 40.
    Eneh, Lynda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg Karlsson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fillinger, Ulrike
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Lindh, Jenny
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Factors associated with preferred Anopheles gambiae s.l. oviposition sitesManuscript (preprint) (Other academic)
  • 41.
    Eneh, Lynda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fillinger, Ulrike
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lindh, Jenny
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Oviposition choice of malaria mosquitoes Anopheles gambiae s.l.:  do they choose between similar habitats?Manuscript (preprint) (Other academic)
  • 42.
    Eneh, Lynda K.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Saijo, Hiromi
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lindh, Jenny M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Rajarao, Gunaratna Kuttuva
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cedrol, a malaria mosquito oviposition attractant is produced by fungi isolated from rhizomes of the grass Cyperus rotundus2016In: Malaria Journal, ISSN 1475-2875, E-ISSN 1475-2875, Vol. 15, article id 478Article in journal (Refereed)
    Abstract [en]

    Background: Cedrol, a sesquiterpene alcohol, is the first identified oviposition attractant for African malaria vectors. Finding the natural source of this compound might help to elucidate why Anopheles gambiae and Anopheles arabiensis prefer to lay eggs in habitats containing it. Previous studies suggest that cedrol may be a fungal metabolite and the essential oil of grass rhizomes have been described to contain a high amount of different sesquiterpenes. Results: Rhizomes of the grass Cyperus rotundus were collected in a natural malaria mosquito breeding site. Two fungi were isolated from an aqueous infusion with these rhizomes. They were identified as Fusarium falciforme and a species in the Fusarium fujikuroi species complex. Volatile compounds were collected from the headspace above fungal cultures on Tenax traps which were analysed by gas chromatography-mass spectrometry (GCMS). Cedrol and a cedrol isomer were detected in the headspace above the F. fujikuroi culture, while only cedrol was detected above the F. falciforme culture. Conclusion: Cedrol an oviposition attractant for African malaria vectors is produced by two fungi species isolated from grass rhizomes collected from a natural mosquito breeding site.

  • 43.
    Eneh, Lynda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Saijo, Hiromi
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lindh, Jenny
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Cedrol, a malaria mosquito oviposition attractant is produced by fungi isolated from rhizomes of the grass Cyperus rotundusManuscript (preprint) (Other academic)
  • 44.
    Finnveden, Maja
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Nameer, Samer
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Johansson, Mats K G
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    One-Component Thiol-Alkene Functional Oligoester Resins Utilizing Lipase Catalysis2016In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935Article in journal (Refereed)
    Abstract [en]

    Chemo-enzymatic methods are powerful tools for the synthesis of novel materials. By combining the flexibility of chemical synthesis and the high selectivity of enzymes, a variety of functional materials can be achieved. In the present study, a series of α,ω-thiol telechelic oligoesters with varying amount of internal alkenes are prepared using selective lipase catalysis and are subsequently cross-linked by thiol-ene chemistry yielding alkene functional networks. Due to the reactivity of thiols and alkenes almost all present thiol-ene systems consist of two components. This work demonstrates that selective lipase catalysis in combination with renewable monomers with internal alkenes is a promising system for achieving one-component thiol-alkene functional resins with good storage stability and a high degree of thiol end-groups. The developed chemo-enzymatic route yields polymer networks with tailored amount of alkene functionalities in the final thermoset, which facilitate further postmodification.

  • 45. Flyborg, L.
    et al.
    Björlenius, Berndt
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Persson, K. M.
    Identification of important physiochemical properties for removal of pharmaceutical residuals in treated wastewater by nanofiltration2013In: AMTA/AWWA Membrane Technology Conference and Exposition 2013, 2013, p. 68-73Conference paper (Refereed)
  • 46. Flyborg, L.
    et al.
    Björlenius, Berndt
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Ullner, M.
    Persson, K. M.
    A PLS model for predicting rejection of trace organic compounds by nanofiltration using treated wastewater as feed2017In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 174, p. 212-221Article in journal (Refereed)
    Abstract [en]

    In this study a Partial Least Squares Projection of Latent Structures (PLS) model has been developed for predicting the rejection of pharmaceutical residuals by nanofiltration (NF) using treated municipal wastewater as feed. The objective was to provide a practical tool for wastewater reuse facilities for estimating the rejection of emerging organic contaminants based on their physiochemical characteristics. The model was developed by identifying the important physiochemical properties of pharmaceutical residuals for rejection by NF. The investigated pharmaceuticals were those present in the effluent from Henriksdal wastewater treatment plant (WWTP), Sweden. The rejection, at volume reduction factors (VRF) ranging from 2 to 20, was examined in a NF pilot plant at two occasions. The important variables for rejection by NF were, in descending order: polarizability, globularity, ratio hydrophobic to polar water accessible surface area and compound charge. Two studies were performed with a time interval of about a year with different wastewater matrices and age of membranes. For different VRFs, but in the same study, the model produced consistent predicted rejections. For the same VRF, but in the different studies, the regression lines were almost parallel, but with a deviation of about 7% for the predicted values. Most of the compounds were within the 95% prediction interval. The model also proved to be able to predict rejection using data from the literature. This confirms that the predictive PLS model can estimate the rejection albeit, with limitations. Generally the proposed predictive rejection model is most likely valid but the model coefficients need to be determined for each individual WWTP or wastewater reuse facility.

  • 47. Gaffney, Darragh
    et al.
    Abdallah, Noreldeen H.
    Cooney, Jakki C.
    Laffir, Fathima R.
    Engelmark Cassimjee, Karim
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Hanefeld, Ulf
    Magner, Edmond
    Preparation and characterisation of a Ni2+/Co2+-cyclam modified mesoporous cellular foam for the specific immobilisation of His(6)-alanine racemase2014In: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, E-ISSN 1873-3158, Vol. 109, p. 154-160Article in journal (Refereed)
    Abstract [en]

    Nickel and cobalt cyclam modified mesocellular foam (MCF) materials were prepared and characterised. The metal cyclam modified materials displayed reduced surface areas and pore diameters in comparison to MCF. The modified materials were used to specifically anchor a histidine tagged form of the enzyme, alanine racemase (HT-AlaR). Non-specific adsorption was predominantly hydrophobic//hydrophilic in nature and could be significantly reduced in the presence of 2% polyethylene glycol. The activity of HT-AlaR immobilised on Ni and Co-MCF was essentially the same as that of the free enzyme, demonstrating that enzymes can be specifically immobilised within the pores of mesoporous materials in a stable and catalytically active manner.

  • 48.
    Gandini, Rosaria
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Reichenbach, Tom
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Tan, Tien-Chye
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Divne, Christina
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Structural basis for dolichylphosphate mannose biosynthesis2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, no 1, article id 120Article in journal (Refereed)
    Abstract [en]

    Protein glycosylation is a critical protein modification. In biogenic membranes of eukaryotes and archaea, these reactions require activated mannose in the form of the lipid conjugate dolichylphosphate mannose (Dol-P-Man). The membrane protein dolichylphosphate mannose synthase (DPMS) catalyzes the reaction whereby mannose is transferred from GDP-mannose to the dolichol carrier Dol-P, to yield Dol-P-Man. Failure to produce or utilize Dol-P-Man compromises organism viability, and in humans, several mutations in the human dpm1 gene lead to congenital disorders of glycosylation (CDG). Here, we report three high-resolution crystal structures of archaeal DPMS from Pyrococcus furiosus, in complex with nucleotide, donor, and glycolipid product. The structures offer snapshots along the catalytic cycle, and reveal how lipid binding couples to movements of interface helices, metal binding, and acceptor loop dynamics to control critical events leading to Dol-P-Man synthesis. The structures also rationalize the loss of dolichylphosphate mannose synthase function in dpm1-associated CDG.The generation of glycolipid dolichylphosphate mannose (Dol-P-Man) is a critical step for protein glycosylation and GPI anchor synthesis. Here the authors report the structure of dolichylphosphate mannose synthase in complex with bound nucleotide and donor to provide insight into the mechanism of Dol-P-Man synthesis.

  • 49. Geisler-Lee, J.
    et al.
    Geisler, M.
    Coutinho, P. M.
    Segerman, B.
    Nishikubo, N.
    Takahashi, J.
    Aspeborg, H.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Djerbi, S.
    Master, E.
    Andersson-Gunneras, S.
    Sundberg, B.
    Karpinski, S.
    Teeri, Tuula T.
    KTH, School of Biotechnology (BIO), Glycoscience.
    Kleczkowski, L. A.
    Henrissat, B.
    Mellerowicz, E. J.
    Poplar carbohydrate-active enzymes. Gene identification and expression analyses2006In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 140, no 3, p. 946-962Article in journal (Refereed)
    Abstract [en]

    Over 1,600 genes encoding carbohydrate-active enzymes (CAZymes) in the Populus trichocarpa (Torr.&Gray) genome were identified based on sequence homology, annotated, and grouped into families of glycosyltransferases, glycoside hydrolases, carbohydrate esterases, polysaccharide lyases, and expansins. Poplar ( Populus spp.) had approximately 1.6 times more CAZyme genes than Arabidopsis ( Arabidopsis thaliana). Whereas most families were proportionally increased, xylan and pectin-related families were underrepresented and the GT1 family of secondary metabolite-glycosylating enzymes was overrepresented in poplar. CAZyme gene expression in poplar was analyzed using a collection of 100,000 expressed sequence tags from 17 different tissues and compared to microarray data for poplar and Arabidopsis. Expression of genes involved in pectin and hemicellulose metabolism was detected in all tissues, indicating a constant maintenance of transcripts encoding enzymes remodeling the cell wall matrix. The most abundant transcripts encoded sucrose synthases that were specifically expressed in wood-forming tissues along with cellulose synthase and homologs of KORRIGAN and ELP1. Woody tissues were the richest source of various other CAZyme transcripts, demonstrating the importance of this group of enzymes for xylogenesis. In contrast, there was little expression of genes related to starch metabolism during wood formation, consistent with the preferential flux of carbon to cell wall biosynthesis. Seasonally dormant meristems of poplar showed a high prevalence of transcripts related to starch metabolism and surprisingly retained transcripts of some cell wall synthesis enzymes. The data showed profound changes in CAZyme transcriptomes in different poplar tissues and pointed to some key differences in CAZyme genes and their regulation between herbaceous and woody plants.

  • 50.
    Gertow, Karin
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. Monash Immunology and Stem Cell Laboratories, Monash University, Wellington Road, Clayton, VIC 3800, Australia .
    Hirst, C. E.
    Yu, Q. C.
    Ng, E. S.
    Pereira, L. A.
    Davis, R. P.
    Stanley, E. G.
    Elefanty, A. G.
    WNT3A promotes hematopoietic or mesenchymal differentiation from hESCs depending on the time of exposure2013In: Stem Cell Reports, ISSN 2213-6711, Vol. 1, no 1, p. 53-65Article in journal (Refereed)
    Abstract [en]

    We investigated the role of canonical WNT signaling in mesoderm and hematopoietic development from human embryonic stem cells (hESCs) using a recombinant human protein-based differentiation medium (APEL). In contrast to prior studies using less defined culture conditions, we found that WNT3A alone was a poor inducer of mesoderm. However, WNT3A synergized with BMP4 to accelerate mesoderm formation, increase embryoid body size, and increase the number of hematopoietic blast colonies. Interestingly, inclusion of WNT3A or a GSK3 inhibitor in methylcellulose colony-forming assays at 4 days of differentiation abrogated blast colony formation but supported the generation of mesospheres that expressed genes associated with mesenchymal lineages. Mesospheres differentiated into cells with characteristics of bone, fat, and smooth muscle. These studies identify distinct effects for WNT3A, supporting the formation of hematopoietic or mesenchymal lineages from human embryonic stem cells, depending upon differentiation stage at the time of exposure.

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