Studentarbeten // Student Theses

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Browsar Studentarbeten // Student Theses efter Program "Bioteknik 300 hp (civilingenjör)"

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    Aggregation av Parkinsonproteinet -synuklein (vildtyp och sjukdomsvarianterna A30P och A53T) samt interaktion med liposomer
    (2017) Lorentzon, Emma; Olsson, Anna; Sundvall, Nathalie; Tingvall Gustafsson, Johanna; Torell Björkman, Agnes; Vånder, Frida; Chalmers tekniska högskola / Institutionen för biologi och bioteknik; Chalmers University of Technology / Department of Biology and Biological Engineering
    Parkinsons sjukdom ¨ar en vanlig ˚aldersrelaterad neurodegenerativ sjukdom, som leder till b˚ade motoriska och kognitiva problem. Sjukdomen karakt¨ariseras av ab-normal ansamling av proteinaggregat, kallade Lewykroppar, inneh˚allande amyloida fibrer. Dessa fibrer best˚ar till stor del av proteinet α-synuklein, som fr¨amst ˚aterfinns i de presynaptiska nervterminalerna, d¨ar det interagerar med bland annat fosfolipider och andra molekyler. Syftet med projektet ¨ar att studera hur tre varianter av α-synuklein, vildtyp samt tv˚a sjukdomsalstrande mutationer, A30P och A53T, aggregerar samt interage-rar med liposomer. Liposomerna best˚ar av DOPC, DOPS, DOPE och kolesterol f¨or att efterlikna synaptiska vesiklar i hj¨arnan. Proteinstruktur samt aggregationskinetik in¨arvaro av liposomer unders¨oktes m.h.a. cirkul¨ar dikroism och fluorescenspektro-skopi. Studien visar att samtliga α-synukleinvarianter interagerar med liposomerna. Vildtypen och A53T-mutanten uppvisar en likartad strukturell f¨or¨andring, i form av en ¨okning av α-helixstruktur, i n¨arvaro av liposomer, medan A30P-mutanten uppvisade l¨agre grad av strukturf¨or¨andring. Aggregationskinetiken f¨or samtliga proteinvarianter inhiberas av de syntetiska liposomerna, vilket observeras m.h.a. tioflavin T fluorescens. Prov inneha˚llande enbart protein aggregerar snabbare ¨an i n¨arvaro av liposomer. Slutsatsen ¨ar att samtliga varianter av α-synuklein interagerar med membran-modellen, som inducerar en f¨or¨andring av deras sekund¨arstruktur. Aggregationen f¨or samtliga proteinvarianter inhiberas i n¨arvaro av membranmodellen.
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    Automated identification of antibiotic resistance mutations in bacterial genomes
    (2017) Boström, Martin; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
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    Biofysikaliska studier av amyloida proteinfibrillers kompaktering
    (2014) Bengtsson, Matilde; Nassif, Jessy; Rundberg, Lisa; Schmidt, Eneas; Sundin, Elin; Svensson, Emelie; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
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    Development & application of a molecular toolbox for the unconventional yeast Candida intermedia
    (2017) Larsson, Adam; Chalmers tekniska högskola / Institutionen för biologi och bioteknik; Chalmers University of Technology / Department of Biology and Biological Engineering
    Over the last years there have been extensive attempts at replacing fossil fuels with the more sustainable option bioethanol. Traditionally bioethanol is produced using Saccharomyces cerevisiae to ferment glucose from crops such as sugar cane, but this is unsustainable as it doesn’t utilize the whole biomass and the resource generationcompeteswithfoodproduction. Insearchofmoresustainablesubstrates the scientific community has turned to more unconventional microorganisms as S. cerevisiae is less adept at using sugars other than glucose. In this project an interesting Candida intermedia strain, named C11, was studied. The strain has exhibited interesting traits for utilization of lactose/galactose and xylose. Three aldose reductase genes, XYL1, XYL1_2 & XYL1_3, have been identified to be of especial interest for xylose metabolism. XYL1_2 also seems to be of interest for lactose/galactose metabolism as the gene is located in a novel galactose gene cluster. The aim of this project was thus to study the physiological roles of the three aldose reductases Xyl1p, Xyl1_2p & Xyl1_3p. The expression levels of the three aldose reductase genes were measured in cells grown in glucose, lactose & xylose to find hints as to the role of the enzymes. XYL1 was found to be upregulated during growth on xylose, whereas XYL1_2 was upregulated in lactose containing growth medium. This suggests Xyl1p’s role to be that of a xylose reductase used in xylose metabolism. It also suggests that Xyl1_2p isimportantforlactose/galactoseutilization. Tofurtherstudythephysiologicalrole of the aldose reductases the goal was to delete them from the genome to obtain a phenotype indicating the role of the enzymes. C. intermedia stronglyfavorsnon-homologousendjoining(NHEJ)overhomologous recombination(HR)makingtargetedgenedeletionsnear-impossible(<1%oftransformed cells). For this reason genetic tools were developed, at great success, for C. intermedia C11 to facilitate gene deletions with a high gene target efficiency. The best obtained deletion protocol was based on an unconventional method of using a split marker deletion cassette. The resulting protocol is quick and provides a gene targeting efficiency of up to 67 %. The deletion protocol was applied in the deletion of aldose reductase gene XYL1_2. The deletion strain did however not produce a visible phenotype when grown on galactose. During the project suggestions as to the metabolic role of Xyl1p & Xyl1_2p were found. A very efficient gene deletion protocol was developed with a gene targeting efficiency of 67 % and it was applied to delete XYL1_2. However, more work is needed to fully evaluate the three aldose reductases and the novel galactose gene cluster, for example by producing more deletion strains.
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    Development and evaluation of an immunoassay for Keratin 5/19 complex in lung cancer
    (2015) Andersson, Sofia; Chalmers tekniska högskola / Institutionen för biologi och bioteknik; Chalmers University of Technology / Department of Biology and Biological Engineering
    14 antibody combinations were evaluated as candidates for a keratin 5/19 enzymeimmunoassay. By enzyme immune assay and western blot, 1A12+Ks19.1 was determined as the superior combination. The most successful test assay was the two-step enzyme immunoassay with 2 hours incubation time for the biotinylated antibody and 1 hour incubation for the HRPconjugated antibody. The experiments used to evaluate antibody combinations also indicates a structural difference between keratin 5/19 in pleura liquid compared to serum and that K5/19 complex containing the N-terminal is likely to be present in serum in higher extent than complex with intact C-terminal. The western blot also revealed cross-reaction of G-2 antibody with keratin 8, although G-2 is stated specific for keratin 5 by its manufacturer. [1] A randomized lung cancer study including 110 lung cancer plasma samples, 52 serum samples of benign lung disease and 52 plasma samples from healthy blood donors was performed. The study was carried out by analyzing the samples in the constructed 1A12+Ks19.1 test and CYFRA21-1. The constructed test was not able to discriminate between histological classes of lung cancer in the lung cancer study. The ability of the test to detect early stage lung cancer varied among the different histological classes. Adenocarcinoma and large cell carcinoma samples detected by the 1A12+Ks19.1 test were progressed cancer, stage III or stage IV. For small cell lung cancer 3 of the 13 early stage lung cancer were detected, indicating the test is thus not suitable for detecting early stages of these histological classes. For Squamous cell carcinoma in lung early stages are detected in larger extent than stage III and IV for K5/19 (1A12+Ks19.1) as a separate test, but primarily in combination with CYFRA21-1 where 9 of 13 early stage samples were detected. From this study one can recommend to perform further studies on early stage SCC in lung to determine the relevance of CYFRA21-1 in combination with 1A12 as diagnostic tool.
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    Diagnosticering av muskelbristning med mikrovågor
    (2015) Berg, Alexander; Gunnarsson, Sofie; Lord, Anton; Löfvall, Max; Nilsson, Simon; Truong, Johnny; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
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    Diagnosticering av muskelbristning med mikrovågor
    (2018) Jönsson, Isak; Pettersen, Emily; Söderberg, Erik; Winald, Alexander; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
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    Diagnosticering av muskelbristning med mikrovågor
    (2017) Bornecrantz, Anton; Ekman, Tim; Fridolfsson, Daniel; Gustavsson, Dennis; Pohjanen, Saga; Törnell, Andreas; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
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    Diagnosticering av muskelbristning med mikrovågor
    (2019) Carlsson, Fanny; Dahlin, Emma; Elander, Rebecka; Moberg, Ida; Nordlund, Frida; Olofsson, David; Chalmers tekniska högskola / Institutionen för elektroteknik; Chalmers University of Technology / Department of Electrical Engineering
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    Differential Expression Analysis and Functional Interpretation of Transcriptome Changes in Neural Progenitors under Temporal Switch
    (2013) Jeggari, Ashwini Priya; Chalmers tekniska högskola / Institutionen för matematiska vetenskaper; Chalmers University of Technology / Department of Mathematical Sciences
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    Elasticity and adhesion measurements of drug crystals by atomic force microscopy
    (2014) Jonsson, Julia; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
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    Electrophoresis of oligonucleotides in the diamond cubic phase of monoolein and water
    (2003) Carlsson, Nils; Chalmers tekniska högskola / Institutionen för fysikalisk kemi; Chalmers University of Technology / Department of Physical Chemistry
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    Elektricitetsalstrande bakterier för avfall-till-energi-applikationer
    (2016) Godman, Staffan; Fjällborg, Daniel; Sjöholm, Emil; Asp, Tobias; Åberg, Marcus; Bremer, Robin; Chalmers tekniska högskola / Institutionen för biologi och bioteknik; Chalmers University of Technology / Department of Biology and Biological Engineering
    Produktion av biobränslen ökar årligen som ett led i omställningen från fossila till förnyelsebara bränslen. En direkt följd är att mängden avfall från dessa processer ökar. I avfallet finns stora mängder outnyttjad energi bundet i organiska molekyler. Genom att använda mikroorganismer som biologiska katalysatorer skulle avfallet kunna konverteras till elkraft, bränslen eller andra mer värdefulla kemikalier. Via sin metabolism kan mikroorganismerna katalysera redoxreaktioner vid elektrolys i bioelektrokemiska system (BES) som exempelvis microbial electrolysis cells (MEC) och microbial fuel cells (MFC). Projektet undersökte möjligheterna att använda MEC med avfallsvatten från fermentation och glycerolavfall från biodieselproduktion med blandade och rena kulturer av Clostridium acetobutylicum och Shewanella oneidensis. C. acetobutylicum visade sig kunna producera laktat i närvaro av glycerolavfall och glukos. S. oneidensis tycktes kunna konsumera laktat under anodiska förhållanden. Ingen biokatalys kunde konstateras för avfallsvatten från fermentation. Under anodiska förhållanden visade sig blandkultur vara fördelaktigt för strömproduktion från glycerolavfall vilket indikerar ett metaboliskt utbyte mellan arterna. Detta kombinerat med den observerade laktatproduktionen utgör ett intressant underlag för framtida forskning. Ytterligare studier i syfte att förbättra biokatalys av glycerolavfall krävs för att utveckla industriella applikationer i större skala. En effektiv återanvändning av avfallet skulle stärka hållbarheten för produktionsprocessen och i förlängningen medföra starkare ekonomiska och miljöbetingade incitament för en biobaserad ekonomi.
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    Engineering of 3 methylaspartate ammonia-lyases for biobased adipic acid production
    (2017) Van Havere, Robin; Chalmers tekniska högskola / Institutionen för biologi och bioteknik; Chalmers University of Technology / Department of Biology and Biological Engineering
    The current traditional adipic acid production is a highly polluting process. Researchers have been studying bio‐based pathways to produce adipic acid in an environmentally sustainable way. One of these bioprocesses could involve the use of a metabolic pathway to produce adipic acid from lysine. The pathway first enzymatic reaction is the deamination of lysine into 6‐aminohex‐2‐enoic acid. No enzyme has been discovered yet to catalyse this reaction. The study of an enzyme able to do this conversion was the main aim of this thesis. Several ammonia lyases were considered as interesting enzymes to study since these enzymes are able to do a deamination on aminoacids, though different than than lysine. The enzyme studied in this research project is 3‐methylaspartate ammonia lyase (MAL) which catalyses the deamination reaction on 3methylaspartic acid. The 3‐methylaspartic acid has a comparable structure to lysine and makes the MAL enzyme an appropriate candidate to study the conversion. However, the MAL enzyme did not show any activity towards lysine. Preliminary results obtained from computational structural biology experiments of MAL in the presence of lysine suggested some mutations that could be done on the enzyme to gain activity on lysine. Therefore, the suggested mutations were implemented in the MAL enzyme, aiming at increasing the size of the binding pocket of MAL to give lysine more space to fit in the active site and make the reaction more feasible. The mutations were successfully introduced in the MAL gene with a site‐directed mutagenic PCR protocol. The mutated MAL genes were then expressed in E.coli BL21 (DE3) and the protein purified. The protein purification was done with two methods that used the same basic principle: an Immobilized Metal‐ion Affinity Chromatography. After the purification, the activity of the mutated enzymes was monitored by various activity assays. The assays provided the kinetic constants of the conversion of the natural substrate, 3‐methyl aspartate, by the mutated enzymes and their plausible activity on lysine by detecting the theoretical conversion products: 6‐aminohex‐2‐enoic acid and ammonia. No activity on lysine was detected, but still valuable information was retrieved from the activity assays. Some of the mutated enzymes like L384A, C361A and C361S showed a tremendous impairment in the activity, which led me to conclude that those residues that were altered are important for the enzyme catalysis.
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    Enzymatisk extrahering och konvertering av lignin för framtida bioraffinaderier
    (2015) Bäckberg, Christoffer; Hagelberg, Arvid; Johansson, Rebecka; Kullberg, Linn; Samuelsson, Louise; Sundström, Clara; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
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    Etanolbildande acetogener för syngasfermentering –en jämförande studie
    (2018) Mårtenson, Sara; Stavås, Emma; Hadi, Fahim; Landström, Carl-Johan; Frithiofson, Emil; Chalmers tekniska högskola / Institutionen för biologi och bioteknik; Chalmers University of Technology / Department of Biology and Biological Engineering
    The use of fossil fuels contributes to global warming, which is one of the biggest pro-blems in today’s society. An alternative to reduce the use of fossil fuels is to instead use renewable fuels, such as bioethanol. One way to produce bioethanol is to allow anaerobic microorganisms to ferment syngas, a mixture of carbon monoxide, carbon dioxide and hydrogen gas. The purpose of the work was to evaluate and rank microorganisms, which by fermentation of syngas, have the greatest potential for high ethanol production. A literature review gathered information of around 100 microorganisms to find the orga-nisms with the greatest potential for ethanol production. The results showed that Clostri-dium autoethanogenum, Clostridium carboxidivorans, Clostridium coskatii, Clostridium ljungdahlii and Clostridium ragsdalei were the microorganisms with the greatest poten-tial. In addition to the literature study, an experiment was performed where inhibitor tolerance was examined. The inhibitor ammonia was added to C. ljungdahlii, C. autoethanogenum and C. carboxidivorans. These three organisms were deemed to have high potential in the literature review and were available at the institution. The result showed that no organism grew at 100 mM of ammonia. C. ljungdahlii showed the highest tolerance as neither ethanol formation nor growth decreased significantly at 50 mM and below. The ethanol production of C. autoethanogenum decreased already at 35 mM. The ethanol production C. carboxidivorans decreased at 50 mM ammonia. The work was carried out at Chalmers University of Technology.
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    Evaluation of new methods to determine antimicrobial efficiency
    (2015) Lancon, Oceane; Chalmers tekniska högskola / Institutionen för biologi och bioteknik; Chalmers University of Technology / Department of Biology and Biological Engineering
    The work for this master's thesis, which was performed at Medibiome, was a part of a Vinnova-funded national project “Innovation mot Infektion” for the establishment and evaluation of a draft standard FprEN 16615 in order to evaluate different disinfection and analytical methods. Healthcare associated infections are a global issue and the need for new methods to reduce contamination and evaluate efficiency of disinfection is increasingly recognized in scientific, clinical and political communities. In order to evaluate the antibacterial efficiency of cleaning and disinfecting products, test floorings were inoculated with bacterial suspensions and an interfering substance, and wiped with a product. A unitary weight was used to standardize the wiping. The bacteria load on the surface was swabbed after wiping and the remaining bacterial load was evaluated after plate cultivation.The ATP bioluminescence analysis was used during a similar procedure to replace the plate cultivation method. The enzyme luciferase provided light emission while degrading the ATP contained into bacteria. The light emission is measured to determine the bacterial load on the surface. The compatibility of wiping materials and cleaning agents was also tested with a test suspension of S. aureus. The recovery of S.aureus and P. aeruginosa after different drying times on surfaces was studied. The results show that three disinfectants meet the requirements of the standard FprEN 1661: DES45, Rely+On™ Virkon® and Wet Wipe. Input was transmitted to the standard committee, especially regarding the need to sterilize the wipes, to standardize and improve the release of bacteria from the swab, and to decrease the weight of the granite block for more clinical relevance. ATP analysis could be performed without background by using an interfering substance modified with Triton X-100 at 0.2%. It seems to be a promising technique, as it is both fast and cost-efficient but further study needs to be done in order to solve technical issues and standardize the method
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    Extraktion och kemisk modifering av hemicellulosa
    (2014) Claesson, Britta; Sjöstrand Dahlberg, Jacob; Oberüller, Jacob; Sundberg, David; Sirén Gustafsson, Lisa; Sörensen, Alexander; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
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    Hydrogeler som vattenbolus för mikrovågshypertermi
    (2016) Ekman, Liam; Hannoun, Stephanie; Lönn, Björn; Wegnelius, Tuva; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems
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    Hydrogeler som vattenbolus för mikrovågshypertermi
    (2014) Bengtsdotter, Bea; Jankkila, Patricia; Larsson, Joel; Nilsson, Jenny; Palmqvist, Daniel; Ridderstolpe, Anna; Chalmers tekniska högskola / Institutionen för signaler och system; Chalmers University of Technology / Department of Signals and Systems