| 1. |
- Andersson, Anneli, et al.
(författare)
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Continuous and simultaneous determination of venous blood metabolites
- 2017
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Ingår i: Talanta. - : Elsevier BV. - 0039-9140. ; 171, s. 270-274
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Tidskriftsartikel (refereegranskat)abstract
- Metabolic syndrome is associated with cardiovascular disease, type 2 diabetes mellitus (T2DM) and prediabetes. Metabolic syndrome is a cluster of interrelated clinical disorders. Difficulties in regulating glucose levels in blood are implicated in many of these disorders. Lactate, another energy metabolite, is produced under anaerobic conditions and can be used to monitor the balance between aerobic and anaerobic metabolism. Tested together, these metabolite levels can provide pro-diagnostic information that improves patient outcomes. Glucose and lactate were determined continuously and simultaneously in whole blood using a dual-channel thermal biosensor device in which one channel employed glucose oxidase for glucose analysis in comparison with lactate oxidase for lactate analysis in the others. No detectable clogging or interference was observed using venous blood samples. The linear detection range for both the glucose and lactate assays was 0.5–45 mM. The sampling rate of up to 24 samples per hour with assay cycle time of 2.5 min was achieved. Comparative analysis between our device and the HemoCue method showed an excellent correlation. The device was stable for hundreds of injections over a period of 45 days. The broad linear range, fast response and detection sensitivity are satisfactory for the clinical requirements, e.g. for diabetic or cardiovascular patients in intensive care units or surgical operation, where the tight control of blood glucose can decrease morbidity or mortality.
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| 2. |
- Adlerberth, Josefin, et al.
(författare)
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Thermometric analysis of blood metabolites in ICU patients
- 2020
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Ingår i: Journal of Thermal Analysis and Calorimetry. - : Springer Science and Business Media LLC. - 1388-6150 .- 1588-2926. ; 140:2, s. 763-771
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Tidskriftsartikel (refereegranskat)abstract
- Real-time monitoring of patient’s blood metabolites, such as glucose and lactate, could potentially improve surgery and recovery outcomes for patients in surgical and intensive care units. Our enzyme thermometric biosensor which is based on flow injected calorimetric determination of immobilized enzyme reaction is capable of performing continuous, fast, and quantitative analysis of metabolites using whole blood. A key technical advantage the assay affords is the ability to use unpretreated whole blood. In this article, the enzyme thermometric biosensor was used, for the first time, to determine glucose and lactate concentrations in the blood of ICU patients. The linear detection range for glucose was 0.5–30 mM and 0.25–12 mM for lactate, using a 20 μL sample volume. A maximum sampling rate of 15 measurements per hour was achieved using venous blood samples, which corresponds to a 4-min measurement interval. In order to validate the accuracy of the results, a comparative analysis between the thermometric biosensor and the clinically applied instrument (LifeScan’s OneTouch®) which is based on disposable dry chemical reaction was performed using samples from 33 patients. The results showed a good correlation between the two methods for both glucose (r = 0.843, p < 0.0001) and lactate (r = 0.78, p = 0.0105). The ability to monitor metabolite levels and trends on a clinically relevant timescale of 5 min is critical for intensive monitoring of ICP and operative patients.
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| 3. |
- Alayash, Abdu I., et al.
(författare)
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Haptoglobin: the hemoglobin detoxifier in plasma
- 2013
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Ingår i: Trends in Biotechnology. - : Elsevier BV. - 0167-7799. ; 31:1, s. 2-3
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Hemoglobin (Hb) is one of the most studied proteins. However, oxidative toxicity associated with free Hb in circulation and its contribution to inflammation and complications of transfusion have only recently become active areas of research. New insights into the protective mechanisms of haptoglobin (Hp), a plasma protein, and a timely resolution of the crystal structure of the Hb-Hp complex made it possible to definitively link the functional and structural interplay between the two proteins. Here, we summarize current knowledge of the interactions between Hb and Hp under oxidative stress conditions, and how Hb's own damaging radicals are harnessed by complex formation. Potential therapeutic benefits of using Hp for inactivation and clearance of free Hb under a number of clinical settings are considered.
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| 4. |
- Andersson, Charlotte, et al.
(författare)
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Enhanced Ribosome and tRNA Contents in Escherichia coli Expressing a Truncated Vitreoscilla Hemoglobin Mutant Analyzed by Flow Field-Flow Fractionation
- 2003
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Ingår i: Biotechnology Letters. - 1573-6776. ; 25:18, s. 1499-1504
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Tidskriftsartikel (refereegranskat)abstract
- The ribosome and tRNA levels of Escherichia coli cells, transformed with a native or mutated Vitreoscilla hemoglobin genes (vhb), were investigated using asymmetrical flow field-flow fractionation (AFFFF). Mutagenesis of vhb by error-prone PCR was carried out to alter the growth behavior of microaerobically cultivated native VHb-expressing E. coli. A VHb mutant, pVMT1, was identified, which was able to reach a remarkably high final A600 of 15, the value of which being 160% higher than that of a VHb control carrying pVHb8 (A600 5.8). AFFFF revealed that cells expressing mutant vhbs showed up to a doubling in the number of active 70S ribosomes cell-1, an almost 3-fold increase in the number of tRNAs cell-1, and up to a 26% increase in the mass fraction of active 70S ribosomes.
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| 5. |
- Andersson, M, et al.
(författare)
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A Novel Selection System for Potato Transformation Using a Mutated AHAS Gene.
- 2003
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Ingår i: Plant Cell Reports. - : Springer Science and Business Media LLC. - 1432-203X .- 0721-7714. ; 22:4, s. 261-267
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Tidskriftsartikel (refereegranskat)abstract
- Acetohydroxyacid synthase (AHAS) is the target enzyme for a number of herbicides. A S653N mutation in the AHAS gene results in an increased tolerance to imidazolinone herbicides. We have investigated the use of the mutated gene as selection gene for potato transformation. This resulted in a transformation system with a very high transformation frequency and low rate of escapes. The mutated AHAS gene was introduced into transformed potato together with a -glucuronidase (GUS) gene. Selection on 0.5 M Imazamox yielded GUS expression in 93–100% of regenerated shoots. Furthermore the mutated AHAS gene was used as selection gene for production of high-amylopectin potato lines. The high transformation frequency was verified and potato lines with the desirable starch quality were obtained.
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| 6. |
- Andersson, Mariette, et al.
(författare)
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Targeted gene suppression by RNA interference: An efficient method for production of high-amylose potato lines
- 2006
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 123:2, s. 137-148
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Tidskriftsartikel (refereegranskat)abstract
- Production of high-amylose potato lines can be achieved by inhibition of two genes coding for starch branching enzymes. The use of antisense technology for gene inhibition have yielded a low frequency of high-amylose lines that mostly was correlated with high numbers of integrated T-DNA copies. To investigate whether the production of high-amylose lines could be improved, RNA interference was used for gene inhibition of the genes Sbe1 and Sbe2. Two constructs with 100 bp segments (pHAS2) or 200 bp segments (pHAS3) of both branching enzyme genes were cloned as inverted repeats controlled by a potato granule-bound starch synthase promoter. The construct pHAS3 was shown to be very efficient, yielding high-amylose quality in more than 50% of the transgenic lines. An antisense construct, included in the study as a comparator, resulted in only 3% of the transgenic lines being of high-amylose type. Noticeable was also that pHAS3 yielded low T-DNA copy inserts with an average of 83% of backbone-free transgenic lines being single copy events.
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| 7. |
- Arvidsson, Pär, et al.
(författare)
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Chromatography of microbial cells using continuous supermacroporous affinity and ion-exchange columns
- 2002
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Ingår i: Journal of Chromatography A. - 0021-9673. ; 977:1, s. 27-38
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Tidskriftsartikel (refereegranskat)abstract
- Continuous supermacroporous chromatographic columns with anion-exchange ligands [2-(dimethylanlino)ethyl group] and immobilized metal affinity (IMA) ligands (Cu2+-loaded iminodiacetic acid) have been developed allowing binding of Escherichia coli cells and the elution of bound cells with high recoveries. These poly(acrylamide)-based continuous supermacroporous columns have been produced by radical co-polymerization of monomers in aqueous solution frozen inside a column (cryo-polymerization). After thawing, the column contains a continuous matrix (so-called cryogel) with interconnected pores of 10-100 mum in size. The large pore size of the matrix makes it possible for E. coli cells to pass unhindered through a plain column containing no ligands. E. coli cells bound to an ion-exchange column at low ionic strength were eluted with 70-80% recovery at NaCl concentrations of 0.35-0.40 M, while cells bound to an IMA-column were eluted with around 80% recovery using either 10 mM imidazole or 20 mM EDTA solutions, respectively. The cells maintain their viability after the binding/elution procedure. These preliminary results indicate that microbial cells can be handled in a chromatographic mode using supermacroporous continuous columns. These columns are easy to manufacture from cheap and readily available starting materials, which make the columns suitable for single-time use. (C) 2002 Published by Elsevier Science B.V.
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| 8. |
- Bagan Navarro, Hector, et al.
(författare)
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Synthesis and characterization of epitope-imprinted polymers for purification of human hemoglobin.
- 2017
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Ingår i: RSC Advances. - 2046-2069. ; 7:66, s. 41705-41712
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Tidskriftsartikel (refereegranskat)abstract
- One promising method to prepare protein-selective polymers is the epitope-imprinting approach, where surface-accessible peptides from a target protein are used as templates to create surface-exposed binding sites on molecularly imprinted polymers (MIPs). However, selection of a suitable peptide target is not always straightforward, and synthesis of peptide on a large scale can be costly. In this work, we developed a new approach that can be used to select peptide epitopes on protein surface to be used as templates to prepare protein-selective MIPs. In this case study, human hemoglobin (Hb) was immobilized on silica nanoparticles and then fragmented by tryptic digestion. The particle-supported peptides were then used as templates to synthesize the Hb-selective MIPs, which were obtained after removal of the silica support and the peptides. The MIPs were tested in equilibrium binding experiments to evaluate their protein separation performance. The new surface imprinted MIPs displayed high selectivity for Hb, and was able to separate different variants of Hb from protein mixtures and crude cell extracts.
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| 9. |
- Becker, Kristian, et al.
(författare)
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Characterization of multimodal hydrophobic interaction chromatography media useful for isolation of green fluorescent proteins with small structural differences.
- 2009
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Ingår i: Journal of Molecular Recognition. - : Wiley. - 1099-1352 .- 0952-3499. ; 22:2, s. 104-109
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Tidskriftsartikel (refereegranskat)abstract
- Hydrophobic interaction chromatography (HIC) has been developed as a powerful technique for separating and purifying proteins. In this study, we have characterized the ability of new multimodal pH-HIC media to resolve proteins with only small differences in their primary structures. This was done by determining the retention times of different green fluorescent protein (GFP) mutants prepared from Escherichia coli extracts. The mutants, modified with single or double hydrophobic amino acid substitutions in two positions, N212 and T230, could be resolved successfully, up to 2.1 column volumes in retention difference for single substitutions and 2.6 column volumes for double substitutions, at two pH and on two media with varying ligand density. The retention times also correlated well with calculated theoretical retentions (R(2) = 0.91) using a hydrophobic descriptor. This medium can therefore be very useful in a final polishing step during purification and the protein library prepared represents a good screening set in validating and characterizing new future media due to the accessible, but yet, extremely small differences in protein structure. Copyright (c) 2008 John Wiley & Sons, Ltd.
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| 10. |
- Becker, Kristian, et al.
(författare)
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Multipurpose peptide tags for protein isolation.
- 2008
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673. ; 1202:1, s. 40-46
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Tidskriftsartikel (refereegranskat)abstract
- A multifunctional peptide tag (HYDHYD) consisting of histidine, tyrosine and aspartate residues was fused to the N-terminal ends of green fluorescent protein (GFP), lactate dehydrogenase (LDH) and human hemoglobin (Hb), proteins which were subjected to ion-exchange chromatography (IEC), aqueous two-phase system partition, immobilized metal-ion affinity chromatography (IMAC), and hydrophobic interaction chromatography (HIC). Tagged GFP was retained significantly longer (>1 column volume) in both HIC and IEC. It exhibited 3x greater partition in favor of the hydrophobic phase in a two-phase system and 96% could be bound to an IMAC column which did not bind native GFP.
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