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  • 101.
    Svedendahl, Maria
    et al.
    KTH, Skolan för bioteknologi (BIO), Biokemi.
    Branneby, Cecilia
    Lindberg, Lina
    Berglund, Per
    KTH, Skolan för bioteknologi (BIO), Biokemi.
    Reversed enantiopreference of an ω-transaminase by a single-point mutationManuskript (preprint) (Annet vitenskapelig)
  • 102. Sánchez, J. L. A.
    et al.
    Henry, O. Y. F.
    Joda, H.
    Solnestam, Beata Werne
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Kvastad, Linda
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Johansson, Erik
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Akan, Pelin
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lundeberg, Joakim
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lladach, N.
    Ramakrishnan, D.
    Riley, I.
    O'Sullivan, C. K.
    Multiplex PCB-based electrochemical detection of cancer biomarkers using MLPA-barcode approach2016Inngår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 82, s. 224-232Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Asymmetric multiplex ligation-dependent probe amplification (MLPA) was developed for the amplification of seven breast cancer related mRNA markers and the MLPA products were electrochemically detected via hybridization. Seven breast cancer genetic markers were amplified by means of the MLPA reaction, which allows for multiplex amplification of multiple targets with a single primer pair. Novel synthetic MLPA probes were designed to include a unique barcode sequence in each amplified gene. Capture probes complementary to each of the barcode sequences were immobilized on each electrode of a low-cost electrode microarray manufactured on standard printed circuit board (PCB) substrates. The functionalised electrodes were exposed to the single-stranded MLPA products and following hybridization, a horseradish peroxidase (HRP)-labelled DNA secondary probe complementary to the amplified strand completed the genocomplex, which was electrochemically detected following substrate addition. The electrode arrays fabricated using PCB technology exhibited an excellent electrochemical performance, equivalent to planar photolithographically-fabricated gold electrodes, but at a vastly reduced cost (>50 times lower per array). The optimised system was demonstrated to be highly specific with negligible cross-reactivity allowing the simultaneous detection of the seven mRNA markers, with limits of detections as low as 25 pM. This approach provides a novel strategy for the genetic profiling of tumour cells via integrated "amplification-to-detection".

  • 103.
    Takwa, Mohamad
    KTH, Skolan för bioteknologi (BIO), Biokemi.
    Lipase Specificity and Selectivity: Engineering, Kinetics and Applied Catalysis2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The specificity and selectivity of the enzyme Candida antarctica lipase B (CALB) were studiedfor several substrates and applications.With help of molecular modeling, the active site of CALB was redesigned for the ring openingpolymerization of D,D‐lactide. Two mutants, with about 90‐fold increase in activity ascompared to the wild‐type enzyme, were created. Changing a glutamine into alanineaccounted for this increase in both mutants by creating a larger space in the acyl donorpocket. The new space made it possible to accommodate the bulky substrate and improvethe transition state‐active site complementarity during polymer chain propagation.The enantioselectivity of CALB towards secondary alcohols was engineered by rationalredesign of the stereoselectivity pocket in the enzyme active site. A larger space created by asingle point mutation resulted in an 8’300’000 times change in enantioselectivity towards 1‐phenylethanol and the enantiopreference was inverted into S‐preference. The activitytowards the S‐enantiomer increased 64’000 times in the mutant as related to the wild‐type.The solvent and temperature effects on the enantioselectivity were studied for severalsubstrates and revealed the importance of entropy in the change in enantioselectivity.Substrate selectivity is of great importance for the outcome of enzyme catalyzed polymersynthesis. Ring opening polymerization (ROP) of γ‐acyloxy‐ε‐caprolactones will result in apolyester chain with pendant functional groups. CALB was found to have activity not onlytowards the lactone but also towards the γ‐ester leading to rearrangement of the monomersyielding γ‐acetyloxyethyl‐γ‐butyrolactone. This selectivity between the lactone and the γ‐ester was dependent on the type of group in the γ position and determined the ratio ofpolymerization and rearrangement of the monomers. Molecular dynamics simulations wereused to gain molecular understanding of the selectivity between the lactone and γ‐ester.In order to obtain (meth)acrylate functional polyesters we investigated the use of 2‐hydroxyethyl (meth)acrylate (HEA and HEMA) as initiators for ring opening polymerization.We found that, in addition to the ring opening polymerization activity, CALB catalyzed thetransacylation of the acid moiety of the initiators. The selectivity of CALB towards thedifferent acyl donors in the reaction resulted in a mixture of polymers with different endgroups. A kinetic investigation of the reaction showed the product distribution with timewhen using HEA or HEMA with ε‐caprolactone or ω‐pentadecalactone.The high selectivity of CALB towards lactones over (meth)acrylate esters such as ethyleneglycol di(meth)acrylate was used to design a single‐step route for the synthesis ofdi(meth)acrylated polymers. By mixing ω‐pentadecalactone with the ethylene glycoldi(meth)acrylate and the enzyme in solvent free conditions, we obtained >95 % ofdi(meth)acrylated polypentadecalactone.Taking advantage of the high chemoselectivity of CALB, it was possible to synthesizepolyesters with thiol and/or acrylate functional ends. When using a thioalcohol as initiatorCALB showed high selectivity towards the alcohol group over the thiol group as acyl acceptorfor the ROP reaction. The enzymatic ability of catalyzing simultaneous reactions (ROP andtransacylation) it was possible to develop a single‐step route for the synthesis ofdifunctionalized polyesters with two thiol ends or one thiol and one acrylate end by mixingthe initiator, lactone and a terminator.

  • 104.
    Tan, Tien-Chye
    et al.
    KTH, Skolan för bioteknologi (BIO), Biokemi (stängd 20130101).
    Haltrich, Dietmar
    Divne, Christina
    KTH, Skolan för bioteknologi (BIO), Biokemi (stängd 20130101).
    Regioselective Control of beta-D-Glucose Oxidation by Pyranose 2-Oxidase Is Intimately Coupled to Conformational Degeneracy2011Inngår i: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 409, nr 4, s. 588-600Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Trametes multicolor pyranose 2-oxidase (P2O) is a flavoprotein oxidase that oxidizes D-glucose at C2 to 2-keto-D-glucose by a highly regioselective mechanism. In this work, fluorinated sugar substrates were used as mechanistic probes to investigate the basis of regioselectivity in P2O. Although frequently used to study the mechanisms of glycoside hydrolases, our work provides the first example of applying these probes to sugar oxidoreductases. Our previous structure of the P2O mutant H167A in complex with the slow substrate 2-deoxy-2-fluoro-D-glucose showed a substrate-binding mode compatible with oxidation at C3. To accommodate the sugar, a gating segment, (FSY456)-F-454, in the substrate recognition loop partly unfolded to create a spacious and more polar active site that is distinct from the closed state of P2O. The crystal structure presented here shows that the preferred C2 oxidation where an ordered complex of P2O H167A with 3-deoxy-3-fluoro-D-glucose at 1.35 angstrom resolution was successfully trapped. In this semi-open C2-oxidation complex, the substrate recognition loop tightens to form an optimized substrate complex stabilized by interactions between Asp452 and glucose O4, as well as Tyr456 and the glucose O6 group, interactions that are not possible when glucose is positioned for oxidation at C3. The different conformations of the (FSY456)-F-454 gating segment in the semiopen and closed states induce backbone and side-chain movements of Thr169 and Asp452 that add further differential stabilization to the individual states. We expect the semi-open state (C2-oxidation state) and closed state to be good approximations of the active-site structure during the reductive half-reaction (sugar oxidation) and oxidative half-reaction (O-2 reduction).

  • 105.
    Thrane, Kim
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Eriksson, Hanna
    Karolinska Inst, Dept Oncol Pathol, SE-17176 Stockholm, Sweden.;Karolinska Univ Hosp, Dept Oncol, SE-17176 Stockholm, Sweden..
    Maaskola, Jonas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Hansson, Johan
    Karolinska Inst, Dept Oncol Pathol, SE-17176 Stockholm, Sweden.;Karolinska Univ Hosp, Dept Oncol, SE-17176 Stockholm, Sweden..
    Lundeberg, Joakim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Spatially Resolved Transcriptomics Enables Dissection of Genetic Heterogeneity in Stage III Cutaneous Malignant Melanoma2018Inngår i: Cancer Research, ISSN 0008-5472, E-ISSN 1538-7445, Vol. 78, nr 20, s. 5970-5979Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cutaneous malignant melanoma (melanoma) is characterized by a high mutational load, extensive intertumoral and intratumoral genetic heterogeneity, and complex tumor microenvironment (TME) interactions. Further insights into the mechanisms underlying melanoma are crucial for understanding tumor progression and responses to treatment. Here we adapted the technology of spatial transcriptomics (ST) to melanoma lymph node biopsies and successfully sequenced the transcriptomes of over 2,200 tissue domains. Deconvolution combined with traditional approaches for dimensional reduction of transcriptome-wide data enabled us to both visualize the transcriptional landscape within the tissue and identify gene expression profiles linked to specific histologic entities. Our unsupervised analysis revealed a complex spatial intratumoral composition of melanoma metastases that was not evident through morphologic annotation. Each biopsy showed distinct gene expression profiles and included examples of the coexistence of multiple melanoma signatures within a single tumor region as well as shared profiles for lymphoid tissue characterized according to their spatial location and gene expression profiles. The lymphoid area in close proximity to the tumor region displayed a specific expression pattern, which may reflect the TME, a key component to fully understanding tumor progression. In conclusion, using the ST technology to generate gene expression profiles reveals a detailed landscape of melanoma metastases. This should inspire researchers to integrate spatial information into analyses aiming to identify the factors underlying tumor progression and therapy outcome. Significance: Applying ST technology to gene expression profiling in melanoma lymph node metastases reveals a complex transcriptional landscape in a spatial context, which is essential for understanding the multiple components of tumor progression and therapy outcome. (C) 2018 AACR.

  • 106. Varemo, Leif
    et al.
    Henriksen, Tora Ida
    Scheele, Camilla
    Broholm, Christa
    Pedersen, Maria
    Uhlen, Mathias
    Pedersen, Bente Klarlund
    Nielsen, Jens
    KTH, Skolan för bioteknologi (BIO), Genteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Type 2 diabetes and obesity induce similar transcriptional reprogramming in human myocytes2017Inngår i: Genome Medicine, ISSN 1756-994X, E-ISSN 1756-994X, Vol. 9, artikkel-id 47Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Skeletal muscle is one of the primary tissues involved in the development of type 2 diabetes (T2D). The close association between obesity and T2D makes it difficult to isolate specific effects attributed to the disease alone. Therefore, here we set out to identify and characterize intrinsic properties of myocytes, associated independently with T2D or obesity. Methods: We generated and analyzed RNA-seq data from primary differentiated myotubes from 24 human subjects, using a factorial design (healthy/T2D and non-obese/obese), to determine the influence of each specific factor on genome-wide transcription. This setup enabled us to identify intrinsic properties, originating from muscle precursor cells and retained in the corresponding myocytes. Bioinformatic and statistical methods, including differential expression analysis, gene-set analysis, and metabolic network analysis, were used to characterize the different myocytes. Results: We found that the transcriptional program associated with obesity alone was strikingly similar to that induced specifically by T2D. We identified a candidate epigenetic mechanism, H3K27me3 histone methylation, mediating these transcriptional signatures. T2D and obesity were independently associated with dysregulated myogenesis, down-regulated muscle function, and up-regulation of inflammation and extracellular matrix components. Metabolic network analysis identified that in T2D but not obesity a specific metabolite subnetwork involved in sphingolipid metabolism was transcriptionally regulated. Conclusions: Our findings identify inherent characteristics in myocytes, as a memory of the in vivo phenotype, without the influence from a diabetic or obese extracellular environment, highlighting their importance in the development of T2D.

  • 107. Vicedomini, Riccardo
    et al.
    Vezzi, Francesco
    KTH, Skolan för datavetenskap och kommunikation (CSC). KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Scalabrin, Simone
    Arvestad, Lars
    KTH, Skolan för datavetenskap och kommunikation (CSC), Beräkningsbiologi, CB. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Policriti, Alberto
    GAM-NGS: genomic assemblies merger for next generation sequencing2013Inngår i: BMC Bioinformatics, ISSN 1471-2105, E-ISSN 1471-2105, Vol. 14, s. S6-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: In recent years more than 20 assemblers have been proposed to tackle the hard task of assembling NGS data. A common heuristic when assembling a genome is to use several assemblers and then select the best assembly according to some criteria. However, recent results clearly show that some assemblers lead to better statistics than others on specific regions but are outperformed on other regions or on different evaluation measures. To limit these problems we developed GAM-NGS (Genomic Assemblies Merger for Next Generation Sequencing), whose primary goal is to merge two or more assemblies in order to enhance contiguity and correctness of both. GAM-NGS does not rely on global alignment: regions of the two assemblies representing the same genomic locus (called blocks) are identified through reads' alignments and stored in a weighted graph. The merging phase is carried out with the help of this weighted graph that allows an optimal resolution of local problematic regions. Results: GAM-NGS has been tested on six different datasets and compared to other assembly reconciliation tools. The availability of a reference sequence for three of them allowed us to show how GAM-NGS is a tool able to output an improved reliable set of sequences. GAM-NGS is also a very efficient tool able to merge assemblies using substantially less computational resources than comparable tools. In order to achieve such goals, GAM-NGS avoids global alignment between contigs, making its strategy unique among other assembly reconciliation tools. Conclusions: The difficulty to obtain correct and reliable assemblies using a single assembler is forcing the introduction of new algorithms able to enhance de novo assemblies. GAM-NGS is a tool able to merge two or more assemblies in order to improve contiguity and correctness. It can be used on all NGS-based assembly projects and it shows its full potential with multi-library Illumina-based projects. With more than 20 available assemblers it is hard to select the best tool. In this context we propose a tool that improves assemblies (and, as a by-product, perhaps even assemblers) by merging them and selecting the generating that is most likely to be correct.

  • 108.
    Vunk, Helian
    KTH, Skolan för bioteknologi (BIO).
    Nästa generations plasmadiagnostik med immunanriktning och riktad proteomik2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 109.
    Wiklund, Martin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Green, Roy
    Univ Southampton, Hants, England .
    Ohlin, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Acoustofluidics 14: Applications of acoustic streaming in microfluidic devices2012Inngår i: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 12, nr 14, s. 2438-2451Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    In part 14 of the tutorial series "Acoustofluidics - exploiting ultrasonic standing wave forces and acoustic streaming in microfluidic systems for cell and particle manipulation", we provide a qualitative description of acoustic streaming and review its applications in lab-on-a-chip devices. The paper covers boundary layer driven streaming, including Schlichting and Rayleigh streaming, Eckart streaming in the bulk fluid, cavitation microstreaming and surface-acoustic-wave-driven streaming.

  • 110.
    Williams, Cecilia
    et al.
    University of Houston, United States; Karolinska Institutet, Sweden .
    Helguero, Luisa
    Karolinska Institutet, Sweden .
    Edvardsson, Karin
    University of Houston, United States; Karolinska Institutet, Sweden .
    Haldosén, Lars-Arne
    Karolinska Institutet, Sweden .
    Gustafsson, Jan-Ake
    University of Houston, United States; Karolinska Institutet, Sweden .
    Gene expression in murine mammary epithelial stem cell-like cells shows similarities to human breast cancer gene expression.2009Inngår i: Breast cancer research : BCR, ISSN 1465-542X, Vol. 11, nr 3, s. R26-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    INTRODUCTION: Mammary stem cells are bipotential and suggested to be the origin of breast cancer development, but are elusive and vaguely characterized. Breast tumors can be divided into subgroups, each one requiring specific treatment. To determine a possible association between mammary stem cells and breast cancer, a detailed characterization of the transcriptome in mammary stem cells is essential.

    METHODS: We have used a murine mammary epithelial stem-like cell line (HC11) and made a thorough investigation of global gene-expression changes during stepwise differentiation using dual-color comparative microarray technique. Subsequently, we have performed a cross-species comparison to reveal conserved gene expression between stem cells and subtype-specific and prognosis gene signatures, and correlated gene expression to in vivo mammary gland development.

    RESULTS: Our analysis of mammary stem-like and stepwise cell differentiation, and an in-depth description of our findings in a breast cancer perspective provide a unique map of the transcriptomic changes and a number of novel mammary stem cell markers. We correlate the alterations to in vivo mammary gland differentiation, and describe novel changes in nuclear receptor gene expression. Interestingly, our comparisons show that specific subtypes of breast cancers with poor prognosis and metastasizing capabilities show resemblance to stem-like gene expression.

    CONCLUSIONS: The transcriptional characterization of these mammary stem-like cells and their differentiation-induced gene expression patterns is here made widely accessible and provides a basis for research on mammary stem-like cells. Our comparisons suggest that some tumors are more stem-like than others, with a corresponding worse prognosis. This information would, if established, be important for treatment decisions. We also suggest several marker candidates valuable to investigate further.

  • 111. Wulff, Ragna Peterson
    et al.
    Lundqvist, Joakim
    Rutsdottir, Gudrun
    Hansson, Andreas
    Stenbaek, Anne
    Elmlund, Dominika
    KTH, Skolan för teknik och hälsa (STH), Strukturell bioteknik.
    Elmlund, Hans
    Jensen, Poul Erik
    Hansson, Mats
    The Activity of Barley NADPH-Dependent Thioredoxin Reductase C Is Independent of the Oligomeric State of the Protein: Tetrameric Structure Determined by Cryo-Electron Microscopy2011Inngår i: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 50, nr 18, s. 3713-3723Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thioredoxin and thioredoxin reductase can regulate cell metabolism through redox regulation of disulfide bridges or through removal of H2O2. These two enzymatic functions are combined in NADPH-dependent thioredoxin reductase C (NTRC), which contains an N-terminal thioredoxin reductase domain fused with a C-terminal thioredoxin domain. Rice NTRC exists in different oligomeric states, depending on the absence or presence of its NADPH cofactor. It has been suggested that the different oligomeric states may have diverse activity. Thus, the redox status of the chloroplast could influence the oligomeric state of NTRC and thereby its activity. We have characterized the oligomeric states of NTRC from barley (Hard rum vulgare L.). This also includes a structural model of the tetrameric NTRC derived from cryo-electron microscopy and single-particle reconstruction. We conclude that the tetrameric NTRC is a dimeric arrangement of two NTRC homodimers. Unlike that of rice NTRC, the quaternary structure of barley NTRC complexes is unaffected by addition of NADPH. The activity of NTRC was tested with two different enzyme assays. The N-terminal part of NTRC was tested in a thioredoxin reductase assay. A peroxide sensitive Mg-protoporphyrin IX monomethyl ester (MPE) cyclase enzyme system of the chlorophyll biosynthetic pathway was used to test the catalytic ability of both the N- and C-terminal parts of NTRC. The different oligomeric assembly states do not exhibit significantly different activities. Thus, it appears that the activities are independent of the oligomeric state of barley NTRC.

  • 112. Zabotina, Olga
    et al.
    Malm, Erik
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Drakakaki, Georgia
    Bulone, Vincent
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Raikhel, Natasha
    Identification and Preliminary Characterization of a New Chemical Affecting Glucosyltransferase Activities Involved in Plant Cell Wall Biosynthesis2008Inngår i: MOLECULAR PLANT, ISSN 1674-2052, Vol. 1, nr 6, s. 977-989Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemical genetics as a part of chemical genomics is a powerful and fast developing approach to dissect biological processes that may be difficult to characterize using conventional genetics because of gene redundancy or lethality and, in the case of polysaccharide biosynthesis, plant flexibility. Polysaccharide synthetic enzymes are located in two main compartments-the Golgi apparatus and plasma membrane-and can be studied in vitro using membrane fractions. Here, we first developed a high-throughput assay that allowed the screening of a library of chemicals with a potential effect on glycosyltransferase activities. Out of the 4800 chemicals screened for their effect on Golgi glucosyltransferases, 66 compounds from the primary screen had an effect on carbohydrate biosynthesis. Ten of these compounds were confirmed to inhibit glucose incorporation after a second screen. One compound exhibiting a strong inhibition effect (ID 6240780 named chemical A) was selected and further studied. it reversibly inhibits the transfer of glucose from UDPglucose by Golgi membranes, but activates the plasma membrane-bound callose synthase. The inhibition effect is dependent on the chemical structure of the compound, which does not affect endomembrane morphology of the plant cells, but causes changes in cell wall composition. Chemical A represents a novel drug with a great potential for the study of the mechanisms of Golgi and plasma membrane-bound glucosyltransferases.

  • 113. Zamani, Leila
    et al.
    Lundqvist, Magnus
    Zhang, Ye
    Åberg, Magnus
    Edfors, Fredrik
    Bidkhori, Gholamreza
    Lindahl, Anna
    Mie, Axel
    Mardinoglu, Adil
    Rockberg, Johan
    Chotteau, Veronique
    High cell density perfusion culture has a maintained exoproteome and metabolomeManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Chinese hamster ovary (CHO) cells are the workhorse to produce recombinant proteins in the biopharmaceutical industry using mammalian cells and are commonly cultured in either fed-batch or perfusion mode. The optimization of the complex biological systems used in such processes is extremely challenging. Multi-omics approaches can reveal otherwise unknown characteristics of these systems and identify culture parameters that can be manipulated to optimize the cultivation process. Here we have ap- plied both metabolomic and proteomic profiling to a monoclonal antibody (mAb) production operated in perfusion mode to explore how cell biology and reactor environment change as the cell density reaches ≥ 200 x 106 cells/mL. The extracellular metabolic composition obtained in perfusion mode was also com- pared to fed-batch, which showed a more stable profile for perfusion despite a far larger range of viable cell densities. The proteomics data showed an increase of structural proteins as the cell density increased, and both the proteomic and metabolic results showed signs of oxidative stress and changes in glutathione metabolism at very high cell densities. The methodology presented herein could be a powerful tool for optimizing cultivation processes and recombinant protein production.

  • 114.
    Zandian, Arash
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Forsström, Björn
    KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Häggmark-Månberg, Anna
    Schwenk, Jochen M.
    KTH, Skolan för bioteknologi (BIO), Proteomik (stängd 20130101). KTH, Skolan för bioteknologi (BIO), Nanobioteknologi (stängd 20130101). KTH, Centra, Science for Life Laboratory, SciLifeLab. KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Uhlén, Mathias
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi.
    Nilsson, Peter
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Ayoglu, Burcu
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Whole-Proteome Peptide Microarrays for Profiling Autoantibody Repertoires within Multiple Sclerosis and Narcolepsy2017Inngår i: Journal of Proteome Research, ISSN 1535-3893, E-ISSN 1535-3907, Vol. 16, nr 3, s. 1300-1314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The underlying molecular mechanisms of autoimmune diseases are poorly understood. To unravel the autoimmune processes across diseases, comprehensive and unbiased analyses of proteins targets recognized by the adaptive immune system are needed. Here we present an approach starting from high-density peptide arrays to characterize autoantibody repertoires and to identify new autoantigens. A set of ten plasma and serum samples from subjects with multiple sclerosis, narcolepsy, and without any disease diagnosis were profiled on a peptide array representing the whole proteome, hosting 2.2 million 12-mer peptides with a six amino acid lateral shift. On the basis of the IgG reactivities found on these whole-proteome peptide micro arrays, a set of 23 samples was then studied on a targeted array with 174 000 12-mer peptides of single amino acid lateral shift. Finally, verification of IgG reactivities was conducted with a larger sample set (n = 448) using the bead-based peptide microarrays. The presented workflow employed three different peptide microarray formats to discover and resolve the epitopes of human autoantibodies and revealed two potentially new autoantigens: MAP3K7 in multiple sclerosis and NRXN1 in narcolepsy. The presented strategy provides insights into antibody repertoire reactivity at a peptide level and may accelerate the discovery and validation of autoantigens in human diseases.

  • 115.
    Zelenin, Sergey
    et al.
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Hansson, Jonas
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Ardabili, Sahar
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Ramachandraiah, Harisha
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Brismar, Hjalmar
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Russom, Aman
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Microfluidic-based isolation of bacteria from whole blood for sepsis diagnostics2015Inngår i: Biotechnology letters, ISSN 0141-5492, E-ISSN 1573-6776, Vol. 37, nr 4, s. 825-830Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Blood-stream infections (BSI) remain a major health challenge, with an increasing incidence worldwide and a high mortality rate. Early treatment with appropriate antibiotics can reduce BSI-related morbidity and mortality, but success requires rapid identification of the infecting organisms. The rapid, culture-independent diagnosis of BSI could be significantly facilitated by straightforward isolation of highly purified bacteria from whole blood. We present a microfluidic-based, sample-preparation system that rapidly and selectively lyses all blood cells while it extracts intact bacteria for downstream analysis. Whole blood is exposed to a mild detergent, which lyses most blood cells, and then to osmotic shock using deionized water, which eliminates the remaining white blood cells. The recovered bacteria are 100 % viable, which opens up possibilities for performing drug susceptibility tests and for nucleic-acid-based molecular identification.

  • 116.
    Zhang, Wang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH). Karolinska institutet.
    Development of novel molecular and microfluidics tools for identification and characterization of latent HIV-1 reservoir2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The existence of latent HIV-1 reservoir (LR) in all HIV-1 infected patients serves as a major obstacle to completely cure HIV-1 infection. However, up to now there is still no available assay that provides an accurate measurement of the reservoir size. This thesis aims to address this challenge from different aspects with several novel technologies, using both molecular and microfluidics-based tools. To find a proper tool to identify the latent HIV-1 reservoir, in Paper I and II, LIPS assay, RNAflow, and RNAscope assay were optimized and evaluated for indirect and direct detection of latent HIV-1 reservoir. The results indicated the LIPS method might not be sufficient for latent HIV-1 reservoir detection, although it has been proposed to quantify the latent HIV-1 reservoir indirectly. Furthermore, the optimized RNAscope technique performed better than RNAflow for transcription and translation competent latent HIV-1 reservoir identification. The RNAscope was also found to be independent of the HIV-1 subtype and can be applied to patient samples at single cell level. As there are currently no available surface biomarkers for latent HIV-1 reservoir, in Paper III, transcriptomics and proteomics-based analysis method for high-throughput selection of potential biomarker were established and applied to different patient groups. Twelve membrane protein-coding genes were identified as downregulated in the patient group who were hypothesized to have lower latent reservoir. These proteins might have the potential to be used as surface biomarkers for latent HIV-1 reservoir. CD4+ T cells, monocyte/macrophages, and natural killer cells are believed to be the primary source for HIV-1 reservoirs in peripheral blood. In paper IV, a microfluidic chip was developed to simultaneously isolate these three mononuclear leukocyte cell types directly from whole blood. The microfluidic method reduces the sample volume requirement and is a promising tool for latent HIV-1 reservoir study. Together, though further improvement and clinical verification are necessary, the work in this thesis has contributed to the advancement of latent HIV-1 reservoir characterization and may facilitate future development of the latent HIV-1 reservoir targeting and clearance methods with the ultimate goal – to cure HIV-1 infection.

  • 117.
    Zhang, Wang
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Nanobioteknologi. karolinska institutet.
    Aljadi, Zenib
    Neogi, Ujjwal
    Russom, Aman
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Nanobioteknologi.
    Microfluidic based immunoaffinity mononuclear leukocytes isolation from whole bloodManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    CD4+ T cells, monocyte/macrophages and natural killer cells are believed to be the main source for HIV-1 reservoirs in peripheral blood. However, despite the potential these subsets of providing a wealth of new information about immune function and host pathology, current HIV latency studies are often based on PBMCs or only CD4+ T cells, mainly due to the lack of appropriate cell subset isolation methods. We present here a microfluidic chip-based method to capture and enrich the three mononuclear cells sub-population peripheral leukocyte sub-populations: CD4+ lymphocytes, natural killer cells and monocytes; using a single source of whole blood (volume < 200 μL) on a single integrated platform, within a time frame of 20 min. The single step isolation method can be used for downstream proteomics and genomics analysis to study the aberrations in these cell types’ functions in critical diseases such as HIV.

  • 118.
    Zhang, Ye
    et al.
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi. KTH, Skolan för bioteknologi (BIO), Centra, Centrum för Bioprocessteknik, CBioPT.
    Stobbe, Per
    Silvander, Christian Orrego
    Chotteau, Veronique
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Very high cell density perfusion of CHO cells anchored in a non-woven matrix-based bioreactor2015Inngår i: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 213, s. 28-41Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recombinant Chinese Hamster Ovary (CHO) cells producing IgG monoclonal antibody were cultivated in a novel perfusion culture system CellTank, integrating the bioreactor and the cell retention function. In this system, the cells were harbored in a non-woven polyester matrix perfused by the culture medium and immersed in a reservoir. Although adapted to suspension, the CHO cells stayed entrapped in the matrix. The cell-free medium was efficiently circulated from the reservoir into- and through the matrix by a centrifugal pump placed at the bottom of the bioreactor resulting in highly homogenous concentrations of the nutrients and metabolites in the whole system as confirmed by measurements from different sampling locations. A real-time biomass sensor using the dielectric properties of living cells was used to measure the cell density. The performances of the CellTank were studied in three perfusion runs. A very high cell density measured as 200 pF/cm (where 1 pF/cm is equivalent to 1 x 106 viable cells/mL) was achieved at a perfusion rate of 10 reactor volumes per day (RV/day) in the first run. In the second run, the effect of cell growth arrest by hypothermia at temperatures lowered gradually from 37 C to 29 C was studied during 13 days at cell densities above 100 pF/cm. Finally a production run was performed at high cell densities, where a temperature shift to 31 C was applied at cell density 100 pF/cm during a production period of 14 days in minimized feeding conditions. The IgG concentrations were comparable in the matrix and in the harvest line in all the runs, indicating no retention of the product of interest. The cell specific productivity was comparable or higher than in Erlenmeyer flask batch culture. During the production run, the final harvested IgG production was 35 times higher in the CellTank compared to a repeated batch culture in the same vessel volume during the same time period.

  • 119.
    Åstrand, Mikael
    KTH, Skolan för bioteknologi (BIO), Proteinteknologi.
    Engineering strategies for ABD-derived affinity proteins for therapeutic and diagnostic applications2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Small stable protein domains are attractive scaffolds for engineering affinity proteins due to their high tolerance to mutagenesis without loosing structural integrity. The albuminbinding domain is a 5 kDa three-helix bundle derived from the bacterial receptor Protein G with low-nanomolar affinity to albumin. In this thesis, the albumin-binding domain is explored as a scaffold for engineering novel affinity proteins with the possible benefit of combining a prolonged serum half-life with specific targeting in a single small scaffold protein. Previously, a library was created by randomizing surface-exposed residues in order to engineer affinity to a new target antigen in addition to the inherent albumin affinity. Here, phage display selections were separately performed against the tumor antigens ERBB2 and ERBB3. The ERBB3 selection resulted in a panel of candidates that were found to have varying affinities to ERBB3 in the nanomolar range, while still retaining a high affinity to albumin. Further characterization concluded that the clones also competed for binding to ERBB3 with the natural activating ligand Heregulin. The selections against ERBB2 resulted in sub-nanomolar affinities to ERBB2 where the binding site was found to overlap with the antibody Trastuzumab. The binding sites on ABD to albumin and either target were found in both selections to be mutually exclusive, as increased concentrations of albumin reduced the level of binding to ERBB2 or ERBB3. An affinity-matured ERBB2 binder, denoted ADAPT6, which lacked affinity to albumin was evaluated as a radionuclide-labeled imaging tracer for diagnosing ERBB2-positive tumors. Biodistribution studies in mice showed a high renal uptake consistent with affinity proteins in the same size range and the injected ADAPT quickly localized to the implanted tumor. High contrast images could be generated and ERBB2-expressing tissue could be distinguished from normal tissue with high contrast, demonstrating the feasibility of the scaffold for use as diagnostic tool. In a fourth study, affinity maturation strategies using staphylococcal cell-surface display were evaluated by comparing two replicate selections and varying the stringency. A sub-nanomolar target concentration was concluded to be inappropriate for equilibrium selection as the resulting output was highly variable between replicates. In contrast, equilibrium sorting at higher concentrations followed by kinetic-focused off-rate selection resulted in high output overlap between attempts and a clear correlation between affinity and enrichment.

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