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1.
Cancer Med ; 13(8): e7048, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38651177

ABSTRACT

BACKGROUND: Multiple myeloma (MM), an incurable disease characterized by frequent relapses and a need for multiple treatments, often progresses to a relapse/refractory status resistant to all available drugs and drug classes. Bispecific antibodies, specifically BCMA T-cell engagers, have emerged as effective treatments for MM, demonstrating impressive efficacy. However, these treatments can adversely affect the immune system, increasing vulnerability to infections. METHODS/RESULTS: This study evaluated the efficacy and safety of BCMA T-cell engagers in 58 Swedish patients with poor MM prognosis. The patients exhibited a 69% overall response rate, with 69% survival and 60% progression-free survival at 15 months. CONCLUSIONS: Despite the risk of infectious complications, the prognosis of MM patients can be significantly improved with vigilant monitoring and proactive management of infections. This real-world data highlight the potential of BCMA T-cell engagers in treating MM, emphasizing the need for careful patient monitoring to mitigate infection risks.


Subject(s)
Antibodies, Bispecific , B-Cell Maturation Antigen , Multiple Myeloma , Humans , Multiple Myeloma/drug therapy , Multiple Myeloma/immunology , Sweden/epidemiology , Male , B-Cell Maturation Antigen/antagonists & inhibitors , B-Cell Maturation Antigen/immunology , Middle Aged , Female , Aged , Antibodies, Bispecific/therapeutic use , Antibodies, Bispecific/adverse effects , Aged, 80 and over , Adult , T-Lymphocytes/immunology , Treatment Outcome , Progression-Free Survival , Antineoplastic Agents, Immunological/therapeutic use , Antineoplastic Agents, Immunological/adverse effects
2.
Environ Sci Technol ; 57(48): 19304-19315, 2023 Dec 05.
Article in English | MEDLINE | ID: mdl-37963269

ABSTRACT

Metamorphosis is a critical process in the life cycle of most marine benthic invertebrates, determining their transition from plankton to benthos. It affects dispersal and settlement and therefore decisively influences the dynamics of marine invertebrate populations. An extended period of metamorphic competence is an adaptive feature of numerous invertebrate species that increases the likelihood of finding a habitat suitable for settlement and survival. We found that crude oil and residues of burnt oil rapidly induce metamorphosis in two different marine invertebrate larvae, a previously unknown sublethal effect of oil pollution. When exposed to environmentally realistic oil concentrations, up to 84% of tested echinoderm larvae responded by undergoing metamorphosis. Similarly, up to 87% of gastropod larvae metamorphosed in response to burnt oil residues. This study demonstrates that crude oil and its burned residues can act as metamorphic inducers in marine planktonic larvae, short-circuiting adaptive metamorphic delay. Future studies on molecular pathways and oil-bacteria-metamorphosis interactions are needed to fully understand the direct or indirect mechanisms of oil-induced metamorphosis in marine invertebrates. With 90% of chronic oiling occurring in coastal areas, this previously undescribed impact of crude oil on planktonic larvae may have global implications for marine invertebrate populations and biodiversity.


Subject(s)
Petroleum , Animals , Petroleum/toxicity , Invertebrates/physiology , Metamorphosis, Biological , Ecosystem , Life Cycle Stages , Larva/metabolism
3.
EJHaem ; 4(3): 647-655, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37601869

ABSTRACT

The treatment of splenic marginal zone lymphoma is debated: splenectomy (the old standard-of-care) is better than chemotherapy but maybe not better than rituximab-containing treatment. We examined all 358 patients diagnosed with splenic marginal zone lymphoma in Sweden 2000-2020. The median overall survival was 11.0 years. The median age was 73 years; 61% were women. Age was the only independently prognostic clinical characteristic. Eighty-six patients were started on wait-and-watch, 90 rituximab monotherapy, 47 rituximab-chemotherapy, 88 splenectomy, 37 chemotherapy, and 10 both systemic therapy and splenectomy. Overall survival was inferior in patients treated with chemotherapy, but equal in patients treated with rituximab, rituximab-chemotherapy and splenectomy. Patients treated with both systemic therapy and splenectomy showed good outcome, suggesting that surgery can be safely reserved for nonresponders. After adjustment for age, survival did not differ between patients started on wait-and-watch and those treated with splenectomy or rituximab-containing therapy. Over time, rituximab use and survival increased in patients ≥73 years. This is, to our knowledge, the largest population-based study of splenic marginal zone lymphoma patients treated with upfront rituximab. We conclude that wait-and-watch remains the most reasonable option in asymptomatic splenic marginal zone lymphoma patients. Symptomatic patients should be offered single-agent rituximab in first line.

4.
Materials (Basel) ; 14(11)2021 May 24.
Article in English | MEDLINE | ID: mdl-34073958

ABSTRACT

Due to increasing demand in manufacturing industries, process optimization has become a major area of focus for researchers. This research optimizes the cryogenic machining of aerospace titanium alloy Ti-6Al-4V for industrial applications by studying the effect of varying the nozzle position using two parameters: the nozzle's separation distance from the tool-chip interface and its inclination angle with respect to the tool rake face. A finite element model (FEM) and computational fluid dynamics (CFD) model are used to simulate the cryogenic impingement of cryogenic carbon dioxide on the tool-workpiece geometry. Experiments are conducted to evaluate cutting forces, tool wear, and surface roughness of the workpiece, and the results are related to the CFD and FEM analyses. The nozzle location is shown to have a significant impact on the cutting temperatures and forces, reducing them by up to 45% and 46%, respectively, while the dominant parameter affecting the results is shown to be the separation distance. Cryogenic machining is shown to decrease adhesion-diffusion wear as well as macroscopic brittle chipping of the cutting insert compared to dry turning, while the workpiece surface roughness is found to decrease by 44% in the case of cryogenic machining.

5.
Vaccine ; 39(7): 1035-1038, 2021 02 12.
Article in English | MEDLINE | ID: mdl-33483213

ABSTRACT

INTRODUCTION: Our aim was to assess response and side effects of 4 doses of TBE vaccine to patients (pts) after allo- and autologous stem cell transplantation (SCT). PATIENTS: Included were 104 pts with leukaemia, myeloma and lymphoma, median age 61 yrs. METHODS: Vaccine (FSME-Immun®) was given at 9, 10, 12, and 21 months post-transplant. Serum samples were obtained before and after vaccinations. Healthy controls (n = 27) received 3 vaccinations. Assessments of TBE specific IgG antibodies were performed by Enzygnost anti-TBE ELISA test (Siemens, Sweden). RESULTS: Antibody levels (>12 U/mL; "seropositivity") were seen in 77% and 80% of pts after allo- and autoSCT; IgG levels; 89 vs 94 U/mL. Ongoing chronic GvHD and immunosuppression (n = 29) was associated with sero-negativity in the last sample (p = 0.007). All controls (n = 27) developed protective antibody levels. CONCLUSIONS: TBE vaccination was safe, and 4 doses starting 9 months post-SCT, induced seropositivity in a vast majority of pts.


Subject(s)
Encephalitis Viruses, Tick-Borne , Encephalitis, Tick-Borne , Hematopoietic Stem Cell Transplantation , Viral Vaccines , Antibodies, Viral , Encephalitis, Tick-Borne/prevention & control , Humans , Middle Aged , Transplantation, Autologous , Vaccination
6.
Materials (Basel) ; 12(17)2019 Sep 02.
Article in English | MEDLINE | ID: mdl-31480695

ABSTRACT

Titanium and titanium alloys such as Ti-6Al-4V are generally considered as difficult-to-machine materials. This is mainly due to their high chemical reactivity, poor thermal conductivity, and high strength, which is maintained at elevated temperatures. As a result, the cutting tool is exposed to rather extreme contact conditions resulting in plastic deformation and wear. In the present work, the mechanisms behind the crater and flank wear of uncoated cemented carbide inserts in the turning of Ti6Al4V are characterized using high-resolution scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and high-resolution Auger electron spectroscopy (AES).The results show that, for combinations of low cutting speeds and feeds, crater and flank wear were found to be controlled by an attrition wear mechanism, while for combinations of medium to high cutting speeds and feeds, a diffusion wear mechanism was found to control the wear. For the latter combinations, high-resolution SEM and AES analysis reveal the formation of an approximately 100 nm thick carbon-depleted tungsten carbide (WC)-layer at the cemented carbide/Ti6Al4V interface due to the diffusion of carbon into the adhered build-up layers of work material on the rake and flank surfaces.

7.
Materials (Basel) ; 12(14)2019 Jul 15.
Article in English | MEDLINE | ID: mdl-31311114

ABSTRACT

Using Ti6Al4V as a work material, a methodology to systematically investigate the diffusion degradation of cemented carbide during machining is proposed. The methodology includes surface characterization of as-tested worn inserts, wet etched worn inserts, metallographic cross-sectioned worn inserts as well as the back-side of the produced chips. Characterization techniques used include scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Auger electron spectroscopy (AES) and time of flight secondary ion mass spectroscopy (ToF-SIMS). The results show that the characterization of wet etched worn inserts gives quick and useful information regarding the diffusion degradation of cemented carbide, in the present work the formation of a fine crystalline W layer (carbon depleted WC layer) at the tool-work material interface. The present study also illuminates the potential of AES analysis when it comes to analyzing the degradation of cemented carbide in contact with the work material during machining. The high surface sensitivity in combination with high lateral resolution makes it possible to analyze the worn cemented carbide surface on a sub-µm level. Especially AES sputter depth profiling, resulting in detailed information of variations in chemical composition across interfaces, is a powerful tool when it comes to understanding diffusion wear. Finally, the present work illustrates the importance of analyzing not only the worn tool but also the produced chips. An accurate characterization of the back-side of the chips will give important information regarding the wear mechanisms taking place at the tool rake face-chip interface. Surface analysis techniques such as AES and ToF-SIMS are well suited for this type of surface characterization.

8.
Artif Cells Nanomed Biotechnol ; 46(sup3): S886-S899, 2018.
Article in English | MEDLINE | ID: mdl-30422688

ABSTRACT

Bacterial biofilm represents a major problem in medicine. They colonize and damage medical devices and implants and, in many cases, foster development of multidrug-resistant microorganisms. Biofilm development starts by bacterial attachment to the surface and the production of extracellular polymeric substances (EPS). The EPS forms a structural scaffold for dividing bacterial cells. The EPS layers also play a protective role, preventing the access of antibiotics to biofilm-associated microorganisms. The aim of this work was to investigate the production nanoparticles that could be used to inhibit biofilm formation. The applied production procedure from rhizome extracts of Rhodiola rosea is simple and environmentally friendly, as it requires no additional reducing, stabilizing and capping agents. The produced nanoparticles were stable and crystalline in nature with an average diameter of 13-17 nm for gold nanoparticles (AuNPs) and 15-30 nm for silver nanoparticles (AgNPs). Inductively coupled plasma mass spectrometry analysis revealed the concentration of synthesized nanoparticles as 3.3 and 5.3 mg/ml for AuNPs and AgNPs, respectively. Fourier-transform infrared spectroscopy detected the presence of flavonoids, terpenes and phenols on the nanoparticle surface, which could be responsible for reducing the Au and Ag salts to nanoparticles and further stabilizing them. Furthermore, we explored the AgNPs for inhibition of Pseudomonas aeruginosa and Escherichia coli biofilms. AgNPs exhibited minimum inhibitory concentrations of 50 and 100 µg/ml, against P. aeruginosa and E. coli, respectively. The respective minimum bactericidal concentrations were 100 and 200 µg/ml. These results suggest that using the rhizome extracts of the medicinal plant R. rosea represents a viable route for green production of nanoparticles with anti-biofilm effects.


Subject(s)
Anti-Bacterial Agents , Biofilms/drug effects , Gold , Metal Nanoparticles/chemistry , Plant Extracts/chemistry , Pseudomonas aeruginosa/physiology , Rhizome/chemistry , Rhodiola/chemistry , Silver , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Biofilms/growth & development , Gold/chemistry , Gold/pharmacology , Silver/chemistry , Silver/pharmacology
9.
J Hazard Mater ; 322(Pt A): 270-275, 2017 Jan 15.
Article in English | MEDLINE | ID: mdl-27045456

ABSTRACT

The use of silver nanoparticles (NPs) in commercial products has become increasingly common in the past decade, mostly due to their antimicrobial properties. Using Ag NP-containing articles may lead to particle release, which raises concern of human and environmental safety. The published literature addressing particle release is scarce, especially when it comes to quantifying exposure to NPs specifically. In this study, we have experimentally investigated the release of total Ag and Ag NP from commercially available toothbrushes i.e. biodegradable toothbrushes for adults and toothbrushes for children. Toothbrushes were immersed and abraded in tap water for 24h corresponding to more than the whole intended usage time of a toothbrush. The total amount of released Ag was quantified by inductively coupled plasma-mass spectrometry (ICP-MS) analysis, and the Ag NPs were characterized by single particle ICP-MS and transmission electron microscopy (TEM). The median size of the released Ag NPs ranged from 42 to 47nm, and the maximum total Ag release was 10.2ng per toothbrush. The adult toothbrushes were generally releasing more total Ag and NPs than children toothbrushes. In conclusion, our results indicate that the use of Ag NP-impregnated toothbrushes can cause consumer as well as environmental exposure to Ag NPs.


Subject(s)
Metal Nanoparticles/chemistry , Silver/chemistry , Toothbrushing/instrumentation , Humans , Microscopy, Electron, Transmission , Water
11.
Water Res ; 81: 269-78, 2015 Sep 15.
Article in English | MEDLINE | ID: mdl-26074190

ABSTRACT

Nine specific compounds identified to migrate from polyethylene (PE) and cross-linked polyethylene (PEX) to drinking water were investigated for their degradation in drinking water. Three sample types were studied: field samples (collected at consumer taps), PEX pipe water extractions, and water samples spiked with target compounds. Four compounds were quantified in field samples at concentrations of 0.15-8.0 µg/L. During PEX pipe water extraction 0.42 ± 0.20 mg NVOC/L was released and five compounds quantified (0.5-6.1 µg/L). The degradation of these compounds was evaluated in PEX-pipe water extractions and spiked samples. 4-ethylphenol was degraded within 22 days. Eight compounds were, however, only partially degradable under abiotic and biotic conditions within the timeframe of the experiments (2-4 weeks). Neither inhibition nor co-metabolism was observed in the presence of acetate or PEX pipe derived NVOC. Furthermore, the degradation in drinking water from four different locations with three different water works was similar. In conclusion, eight out of the nine compounds studied would - if being released from the pipes - reach consumers with only minor concentration decrease during water distribution.


Subject(s)
Drinking Water/chemistry , Organic Chemicals/analysis , Water Pollutants, Chemical/analysis , Denmark , Polyethylene/chemistry , Time Factors , Water Quality , Water Supply
12.
Waste Manag ; 34(9): 1627-36, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24889793

ABSTRACT

Municipal solid waste incineration (MSWI) plays an important role in many European waste management systems. However, increasing focus on resource criticality has raised concern regarding the possible loss of critical resources through MSWI. The primary form of solid output from waste incinerators is bottom ashes (BAs), which also have important resource potential. Based on a full-scale Danish recovery facility, detailed material and substance flow analyses (MFA and SFA) were carried out, in order to characterise the resource recovery potential of Danish BA: (i) based on historical and experimental data, all individual flows (representing different grain size fractions) within the recovery facility were quantified, (ii) the resource potential of ferrous (Fe) and non-ferrous (NFe) metals as well as rare earth elements (REE) was determined, (iii) recovery efficiencies were quantified for scrap metal and (iv) resource potential variability and recovery efficiencies were quantified based on a range of ashes from different incinerators. Recovery efficiencies for Fe and NFe reached 85% and 61%, respectively, with the resource potential of metals in BA before recovery being 7.2%ww for Fe and 2.2%ww for NFe. Considerable non-recovered resource potential was found in fine fraction (below 2mm), where approximately 12% of the total NFe potential in the BA were left. REEs were detected in the ashes, but the levels were two or three orders of magnitude lower than typical ore concentrations. The lack of REE enrichment in BAs indicated that the post-incineration recovery of these resources may not be a likely option with current technology. Based on these results, it is recommended to focus on limiting REE-containing products in waste for incineration and improving pre-incineration sorting initiatives for these elements.


Subject(s)
Incineration , Metals/analysis , Recycling , Waste Products/analysis
13.
J Crohns Colitis ; 8(8): 789-95, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24418661

ABSTRACT

BACKGROUND AND AIMS: Ileocaecal resection for Crohn's disease is commonly performed. The severity of endoscopic lesions in the anastomotic area one year postoperatively is considered to reflect the subsequent clinical course. Fecal calprotectin (FC) has been shown to correlate with the findings at ileocolonoscopy in Crohn's disease. The objectives of this study were to assess whether the concentration of FC reflects the endoscopic findings one year after ileocaecal resection and to evaluate the variation of FC in individual patients during 6months prior to the ileocolonoscopy. METHODS: Thirty patients with Crohn's disease and ileocaecal resection performed within one year were included. Stool samples were delivered monthly until an ileocolonoscopy was performed one year postoperatively. RESULTS: One year after surgery the median values of FC were not significantly different between the patients in endoscopic remission (n=17) and the patients with an endoscopic recurrence (189 (75-364) vs 227 (120-1066)µg/g; p=0.25). However, most patients with low values were in remission and all patients with high (>600µg/g) calprotectin values had recurrent disease. The variability of the FC concentration was most pronounced in patients with diarrhea. CONCLUSIONS: We found no statistical difference in the concentrations of calprotectin between patients in endoscopic remission and patients with a recurrent disease one year after ileocaecal resection for Crohn's disease. However, among the minority of patients with low or high values, FC indicated remission and recurrence, respectively. There was significant variation of the fecal calprotectin concentrations over time, which affects the utility of calprotectin in clinical practice.


Subject(s)
Cecum/surgery , Colonoscopy , Crohn Disease/surgery , Feces/chemistry , Ileum/surgery , Leukocyte L1 Antigen Complex/analysis , Adolescent , Adult , Crohn Disease/pathology , Female , Humans , Male , Middle Aged , Recurrence , Remission Induction , Young Adult
14.
Sci Total Environ ; 442: 420-31, 2013 Jan 01.
Article in English | MEDLINE | ID: mdl-23183122

ABSTRACT

Mitigation activities to improve water quality and quantity in streams as well as stream management and restoration efforts are conducted in the European Union aiming to improve the chemical, physical and ecological status of streams. Headwater streams are often characterised by impairment of hydromorphological, chemical, and ecological conditions due to multiple anthropogenic impacts. However, they are generally disregarded as water bodies for mitigation activities in the European Water Framework Directive despite their importance for supporting a higher ecological quality in higher order streams. We studied 11 headwater streams in the Hove catchment in the Copenhagen region. All sites had substantial physical habitat and water quality impairments due to anthropogenic influence (intensive agriculture, urban settlements, contaminated sites and low base-flow due to water abstraction activities in the catchment). We aimed to identify the dominating anthropogenic stressors at the catchment scale causing ecological impairment of benthic macroinvertebrate communities and provide a rank-order of importance that could help in prioritising mitigation activities. We identified numerous chemical and hydromorphological impacts of which several were probably causing major ecological impairments, but we were unable to provide a robust rank-ordering of importance suggesting that targeted mitigation efforts on single anthropogenic stressors in the catchment are unlikely to have substantial effects on the ecological quality in these streams. The SPEcies At Risk (SPEAR) index explained most of the variability in the macroinvertebrate community structure, and notably, SPEAR index scores were often very low (<10% SPEAR abundance). An extensive re-sampling of a subset of the streams provided evidence that especially insecticides were probably essential contributors to the overall ecological impairment of these streams. Our results suggest that headwater streams should be considered in future management and mitigation plans. Catchment-based management is necessary because several anthropogenic stressors exceeded problematic thresholds, suggesting that more holistic approaches should be preferred.


Subject(s)
Fresh Water/analysis , Invertebrates/drug effects , Water Pollutants, Chemical/analysis , Water Quality/standards , Animals , Denmark , Environmental Monitoring , Fresh Water/chemistry , Geologic Sediments/analysis , Invertebrates/growth & development , Urbanization , Water Pollutants, Chemical/toxicity
16.
J Innate Immun ; 3(6): 594-604, 2011.
Article in English | MEDLINE | ID: mdl-21921589

ABSTRACT

Blood eosinophil numbers may be elevated in allergy, inflammatory bowel disease and eosinophilic esophagitis. The aim of this study was to examine whether circulating eosinophils display distinct phenotypes in these disorders and if different patterns of eosinophilic chemoattractants exist. Blood eosinophils from patients with symptomatic eosinophilic esophagitis (EoE; n = 12), ulcerative colitis (n = 8), airway allergy (n = 10) and healthy controls (n = 10) were enumerated and their surface markers analyzed by flow cytometry. Plasma levels of pro-eosinophilic cytokines were quantified in parallel. Data were processed by multivariate pattern recognition methods to reveal disease-specific patterns of eosinophil phenotypes and cytokines. EoE patients had higher numbers of eosinophils with enhanced expression of CD23, CD54, CRTH2 and CD11c and diminished CCR3 and CD44 expression. Plasma CCL5 was also increased in EoE. Although allergic patients had increased interleukin (IL)-2, IL-3, IL-5 and granulocyte macrophage colony-stimulating factor plasma concentrations, their blood eosinophil phenotypes were indistinguishable from those of healthy controls. Decreased eosinophilic expression of CD11b, CD18, CD44 and CCR3, but no distinctive pattern of eosinophil chemoattractants, characterized ulcerative colitis. We propose that eosinophils acquire varying functional properties as a consequence of distinct patterns of activation signals released from the inflamed tissues in different diseases.


Subject(s)
Antigens, CD/metabolism , Eosinophilic Esophagitis/immunology , Eosinophils/metabolism , Inflammatory Bowel Diseases/immunology , Respiratory Hypersensitivity/immunology , Adolescent , Adult , Cell Count , Cell Differentiation , Cell Separation , Cellular Microenvironment , Cytokines/genetics , Cytokines/metabolism , Eosinophilic Esophagitis/blood , Eosinophils/immunology , Eosinophils/pathology , Female , Flow Cytometry , Gene Expression Regulation/immunology , Humans , Inflammatory Bowel Diseases/blood , Male , Middle Aged , Respiratory Hypersensitivity/blood
17.
Phytochemistry ; 70(9): 1123-1128, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19664791

ABSTRACT

A method based on the laser microdissection pressure catapulting technique has been developed for isolation of whole intact cells. Using a modified tissue preparation method, one outer pair of apical cells and two pairs of sub-apical, chloroplast-containing cells, were isolated from glandular secretory trichomes of Artemisia annua. A. annua is the source of the widely used antimalarial drug artemisinin. The biosynthesis of artemisinin has been proposed to be located to the glandular trichomes. The first committed steps in the conversion of FPP to artemisinin are conducted by amorpha-4,11-diene synthase, amorpha-4,11-diene hydroxylase, a cytochrome P450 monooxygenase (CYP71AV1) and artemisinic aldehyde Delta11(13) reductase. The expression of the three biosynthetic enzymes in the different cell types has been studied. In addition, the expression of farnesyldiphosphate synthase producing the precursor of artemisinin has been investigated. Our experiments showed expression of farnesyldiphosphate synthase in apical and sub-apical cells as well as in mesophyl cells while the three enzymes involved in artemisinin biosynthesis were expressed only in the apical cells. Elongation factor 1alpha was used as control and it was expressed in all cell types. We conclude that artemisinin biosynthesis is taking place in the two outer apical cells while the two pairs of chloroplast-containing cells have other functions in the overall metabolism of glandular trichomes.


Subject(s)
Artemisia annua/metabolism , Artemisinins/metabolism , Alkyl and Aryl Transferases/metabolism , Artemisia annua/cytology , Artemisia annua/enzymology , Base Sequence , Chloroplasts/metabolism , Cytochrome P-450 Enzyme System/metabolism , Gas Chromatography-Mass Spectrometry , Oxidoreductases/metabolism , Plant Leaves/enzymology , Plant Leaves/metabolism , Plant Proteins/metabolism
18.
Protein Expr Purif ; 51(1): 71-9, 2007 Jan.
Article in English | MEDLINE | ID: mdl-16908191

ABSTRACT

Amorpha-4,11-diene synthase (ADS) from Artemisia annua and (+)-germacrene synthase (GDS) from Zingiber officinale were expressed in Escherichia coli under different conditions to optimize the yield of active soluble protein. The cDNAs of these enzymes were inserted into the pET28 vector (Novagen) and expressed in four different bacterial strains; BL21 (DE3), BL21 (DE3) Tuner, BL21 (DE3) pLysS and BL21 (DE3) pLysS Tuner using different inducing agents (IPTG, The Inducer). The effects of induction under osmotic stress in the presence of glycine betaine and sorbitol were investigated. Although background expression for ADS was reduced when using pLysS strains, no significant difference was noted for ADS activity in soluble whole cell lysates after induction with either IPTG or The Inducer. For GDS, on the other hand, the change between BL21 (DE3) cells and BL21 (DE3) Tuner, induced with IPTG, leads to a twofold increase in enzyme activity in the soluble fraction while a reduction in activity is observed when using the pLysS strains. The same doubling of activity is observed for GDS when the commonly used BL.21 (DE3) is induced with The Inducer. Addition of 2.5 mM glycine betaine and 660 mM sorbitol to the bacterial growth media resulted in reduction of growth rate and biomass yield but under these conditions the best overall protein production, for both enzymes, was obtained. Compared to the standard conditions previously used in our laboratory the yield of soluble active protein was increased 7- and 2.5-fold for ADS and GDS, using BL21 (DE3) pLysS Tuner and BL21 (DE3), respectively.


Subject(s)
Alkyl and Aryl Transferases/biosynthesis , Artemisia annua/enzymology , Recombinant Fusion Proteins/biosynthesis , Zingiber officinale/enzymology , Betaine/pharmacology , Enzyme Induction , Escherichia coli/enzymology , Isopropyl Thiogalactoside/pharmacology , Molecular Biology , Osmotic Pressure/drug effects , Protein Folding , Sorbitol/pharmacology
19.
Arch Biochem Biophys ; 452(1): 17-28, 2006 Aug 01.
Article in English | MEDLINE | ID: mdl-16839518

ABSTRACT

A cDNA clone encoding a sesquiterpene synthase, (+)-germacrene D synthase, has been isolated from ginger (Zingiber officinale). The full-length cDNA (AY860846) contains a 1650-bp open reading frame coding for 550 amino acids (63.8kDa) with a theoretical pI=5.59. The deduced amino acid sequence is 30-46% identical with sequences of other sesquiterpene synthases from angiosperms. The recombinant enzyme, produced in Escherichia coli, catalyzed the formation of a major product, (+)-germacrene D (50.2% of total sesquiterpenoids produced) and a co-product, germacrene B (17.1%) and a number of minor by-products. The optimal pH for the recombinant enzyme is around 7.5. Substantial (+)-germacrene D synthase activity is observed in the presence of Mg2+, Mn2+, Ni2+ or Co2+, while the enzyme is inactive when Cu2+ or Zn2+ is used. The Km- and kcat-values are 0.88 microM and 3.34 x 10(-3) s(-1), respectively. A reaction mechanism involving a double 1,2-hydride shift has been established using deuterium labeled substrates in combination with GC-MS analysis.


Subject(s)
Alkyl and Aryl Transferases , DNA, Complementary/genetics , Gene Expression Regulation, Enzymologic , Zingiber officinale/enzymology , Alkyl and Aryl Transferases/genetics , Alkyl and Aryl Transferases/isolation & purification , Alkyl and Aryl Transferases/metabolism , Amino Acid Sequence , Carbon-Carbon Lyases/genetics , Carbon-Carbon Lyases/metabolism , Catalysis , Cloning, Molecular , Escherichia coli/enzymology , Gas Chromatography-Mass Spectrometry , Hydrogen-Ion Concentration , Kinetics , Magnesium/pharmacology , Magnoliopsida/enzymology , Metals, Heavy/pharmacology , Molecular Sequence Data , Open Reading Frames/genetics , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Thermodynamics
20.
Biotechnol Lett ; 28(8): 571-80, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16614895

ABSTRACT

The gene encoding for amorpha-4,11-diene synthase from Artemisia annua was transformed into yeast Saccharomyces cerevisiae in two fundamentally different ways. First, the gene was subcloned into the galactose-inducible, high-copy number yeast expression vector pYeDP60 and used to transform the Saccharomyces cerevisiae strain CEN.PK113-5D. Secondly, amorpha-4,11-diene synthase gene, regulated by the same promoter, was introduced into the yeast genome by homologous recombination. In protein extracts from galactose-induced yeast cells, a higher activity was observed for yeast expressing the enzyme from the plasmid. The genome-transformed yeast grows at the same rate as wild-type yeast while plasmid-carrying yeast grows somewhat slower than the wild-type yeast. The plasmid and genome-transformed yeasts produced 600 and 100 microg/l of the artemisinin precursor amorpha-4,11-diene, respectively, during 16-days' batch cultivation.


Subject(s)
Alkyl and Aryl Transferases/metabolism , Artemisia annua/enzymology , Artemisinins/metabolism , Genetic Engineering/methods , Saccharomyces cerevisiae/genetics , Sesquiterpenes/metabolism , Alkyl and Aryl Transferases/genetics , Artemisia annua/genetics , Artemisinins/chemistry , Blotting, Western , Gas Chromatography-Mass Spectrometry , Genome, Fungal/genetics , Molecular Structure , Plasmids/genetics , Polyisoprenyl Phosphates/chemistry , Polyisoprenyl Phosphates/metabolism , Recombination, Genetic , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae/metabolism , Sesquiterpenes/chemistry , Transformation, Genetic
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