G protein signaling depends on the ability of the individual subunits of the G protein heterotrimer to assemble into a functional complex. Formation of the G protein βγ (Gβγ) dimer is particularly challenging because it is an obligate dimer in which the individual subunits are unstable on their own. Recent studies have revealed an intricate chaperone system that brings the Gβ and Gγ subunits together. This system includes the cytosolic chaperonin containing TCP-1 (CCT) and a co-chaperone phosducin-like protein 1 (PhLP1). Two key intermediates in the Gβγ assembly process, the Gβ-CCT and the PhLP1-Gβ-CCT complexes, were isolated and their structures determined by cryo-electron microscopy, chemical cross-linking coupled with mass spectrometry, and unnatural amino acid cross-linking. These structures show that Gβ interacts with CCT in a near-native state through interactions of the Gγ-binding region of Gβ with the CCTγ subunit. PhLP1 binding stabilizes the Gβ β-propeller, disrupting interactions with CCT and releasing a PhLP1-Gβ dimer for assembly with Gγ. We also investigated the role of CCT and PhLP1 in folding and assembling mTOR complexes, which regulate cell growth through phosphorylation. We found that the β-propeller protein mLST8 and one of its binding partners called raptor, which is a large protein in which one domain forms a β-propeller, both bind to CCT. PhLP1 forms a ternary complex with mLST8 and CCT and may play a co-chaperone role. Depletion of PhLP1 or CCT reduces assembly of mTOR complexes in the cell. Collectively, this report reveals diversity in the contributions of CCT to the formation of protein complexes in signaling pathways and presents a molecular mechanism of Gβ folding by CCT and PhLP1.

Today, paper and paperboard is an important part of the packaging industry, as well as natural part of our daily lives. The alternatives to paper and paperboard is often produced from nonrenewable sources such as petroleum and as demands on sustainability increase in the packaging sector, it gives paper a desirable advantage over plastics. To increase the use of paper, some of the limiting factors for paper needs to be overcome, such as its limited formability. One way to create a paper that can be formed in new ways is to imbibe the paper with an additive that makes its modulus changeable. This would make it possible to control the stiffness of the paper which would make it more formable. This have been the aim of this thesis. To create this formable paper four different approaches were used. Of these four, three included how paper can be treated with polyelectrolytes to be able to increase its modulus when stimuli are applied. The two first approaches were based on the layer-by-layer technique adsorbing alginate and cationic fibrils to form a layer that could be cross-linked, either on the surface of a film (the first approach) or in the network of fibres in a porous paper (the second approach). The last approach was to impregnate the papers with alginate. The results show that the first approach gave a too low adsorption of polyelectrolytes, why no difference could be detected. The second approach resulted in a higher adsorbed amount, but the effects were still too small. The third approach gave a paper which could, depending on the concentration of alginate, either increase or decrease its modulus when cross-linked. The last approach was to create a laminate, using unmodified fibers together with dialcohol cellulose fibres. This resulted in a paper that could be formed using heat and allowing the paper to cool down in the desirable form. In the curriculum for chemistry in Swedish high schools there is a paragraph that says that research in chemistry should be a part of the content the students learn. This is a challenge both to teachers and researchers. For teachers, to find research at an appropriate level and teach it in an understandable way. For researchers, to communicate the research so it is understandable for society. With this as a motivation, a second part of this thesis discuss the method flipped classroom in chemistry education at Swedish high schools. It was seen that from the teacher’s perspective, flipped classroom meant advantages that could be categorized into five categories. The categories that was found were Time to interact, Student responsibility, dialogue, laboratory work and understanding and using the language. / Pappers- och kartongindustrin är idag en viktig del av förpackningsindustrin. Alternativ till kartong är ofta producerat av icke-förnybara råvaror och idag när kraven på hållbarhet ökar ger detta kartong en fördel mot plast. För att öka användningsområdena för kartong så måste de begränsningar som materialet har idag övervinnas. Detta gäller till exempel formbarheten. Ett sätt att skapa kartong som kan bli format på nya sätt är att göra en additiv tillsats till papperet som har egenskapen att det kan variera sin styvhet. Detta skulle göra det möjligt att kontrollera papperets styvhet, vilket har varit målet för det här arbetet. Genom att använda fyra olika arbetssätt har denna egenskap försökts åstadkommas. Tre av arbetssätten har behandlat papper med polyelektrolyter vars E-modul kan ökas med hjälp av något stimuli. I de två första försöken applicerades polyelektrolyterna genom den så kallade lager-på-lager-tekniken, där alginat och katjoniska cellulosafibriller adsorberades, i första försöket på ytan av en film och i det andra på ytan av fibrerna i fibernätverket i ett poröst papper. I det tredje försöket impregnerades de orösa papperna med alginat. Resultatet från det första försöket var att adsorptionen inte gav någon effekt eftersom den absorberande mängden var för låg. I det andra försöket var adsorptionen högre men det påverkade inte de mekaniska egenskaperna nämnvärt. I det tredje försöket med impregnering så kunde en ändring av E-modulen observeras när systemet tvärbands. I det sista försöket användes en metod som byggde på laminering. Ett ark av modifierade fibrer guskades ihop med ett ark med dialkoholcellulosefibrer. De försök som gjordes tyder på att papperet kunde formas och kunde fås att behålla formen om det värmdes och kyldes i den önskade formen. I läroplanen för kemi på gymnasiet finns en paragraf som beskriver hur kemiundervisningen ska ha inslag av forskning. Detta är en utmaning för både lärare och forskare. Lärarnas utmaning består i att finna forskning på en bra nivå för eleverna och att förklara den på ett förståeligt sätt. För forskare består utmaningen i att kommunicera forskningen på ett förståeligt sätt till samhället. Med detta som motivering har detta arbete en utbildningsdel. I den har lärares perspektiv på metoden ”flipped classroom” i kemiklassrummet undersökts. Flipped classroom beskrevs ha styrkor och dessa kunde kategoriseras i fem kategorier. Kategorierna var tid för interaktion, elevens ansvar, dialog, laborationer och förstå och använda språket.

The primary objectives of this study were to develop an effective reactive extrusion process to produce granular phosphorylated pea starches with enhanced enzyme resistance, and examine the effects of bulk phosphorylation conditions on the morphology, physicochemical and functional properties of extruded pea starch phosphates. Two types of commercially available pea starches (NutriPea and Meelunie) were chosen as the research subjects in this study with differing native resistance. A number of methods including optical microscopy, SEM, ICP-OES, Englyst method, DSC and rapid visco analysis (RVA) were used to characterize the morphology and properties of extruded pea starches. The effects of feed formulations and extrusion conditions on phosphorus incorporation and Englyst digestion profiles were examined systemically. The results showed that phosphorus content and digestion profiles were highly dependent on the feed moisture. Enzyme resistance did not positively correlate with phosphorus content for extruded pea starch phosphates in contrast to their counterparts prepared by conventional aqueous slurry. This was because extrusion processing can markedly increase the susceptibility of pea starch granules to enzymatic digestion. Lower feed moisture content (40%) gave lower phosphorus content, significantly lower RDS content, and higher SDS and/or RS content. Bulk phosphorylation in the extruder resulted in decreased RS2 content but increased RS4 content. Screw geometry with excessive mixing index was not desirable in terms of producing resistant starch. High screw speeds (150rpm and 200rpm) and low feed rate (1.02kg/h) brought about higher yields of SDS and RS in spite of lower phosphorus incorporation. Reactive extrusion of pea starches under optimized conditions achieved a significant but moderate increase either in RS content (from 18.67% to 22.57% for NutriPea) or in SDS content (from 37.18% to 42.23% for Meelunie) compared to their native counterparts. However, RS and SDS content could not be improved simultaneously at least based on these pea starches and the reactive extrusion processes in this study. The optical and SEM micrographs confirmed that the granule integrity was largely retained after optimized reactive extrusion process. DSC thermograms found no significant correlation between gelatinization characteristics and Englyst digestion profiles. Evidenced by RVA pasting profiles, NutriPea pea starch phosphates exhibited enhanced thermal and shear stability in comparison to their native counterpart. A novel foaming injection technology of cross-linking reagents solution was pioneeringly introduced to uniformly coat all starch particles at the lowest moisture level possible during the continuous production of granular NutriPea pea starch phosphates. Yet, the resulting phosphorus incorporation was much lower than expected and would require further studies. / Thesis / Master of Applied Science (MASc) / The Canadian food industry is increasingly interested in the potential to probe new avenues to produce enzyme-resistant food starches from pulses starches. Although extrusion cooking is commonly used for manufacturing cereals, snacks and other food products, no research has been reported on using an extruder to rapidly produce resistant pulse starches for functional food ingredients. This study aimed to develop an effective reactive extrusion process to produce phosphate cross-linked pea starches with enhanced enzyme resistance (i.e., increased slowly digestible starch (SDS) and resistant starch (RS) content ) based on an examination of the effects of reaction conditions on the properties of extrusion products. Two types of commercially available pea starches, NutriPea and Meelunie, were chosen as subjects of the research. The cross-linked pea starches under optimized conditions achieved a significant but moderate increase either in RS content (for NutriPea) or in SDS content (for Meelunie) compared to their native counterparts. However, RS and SDS content could not be improved simultaneously at least based on these pea starches and the reactive extrusion processes in this study.

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The abiotic oxidation of pyrite requires the supply of oxygen and water only. In abiotic systems, pyrite oxidation may proceed via several paths, with multiple steps in each of the paths. Defect sites (S-deficient, Fe3+ bearing sites) on the pyrite surface have been shown reported to be the initial reaction sites on pristine pyrite surfaces. In neutral to slightly acidic solutions (3.5<pH<7), ferric iron hydroxide patches will form on the surface. These patches have been shown to be the predominant sites for electron exchange. Efforts were undertaken to suppress the electron transfer at these sites to inhibit pyrite oxidation. It has been shown that pyrite oxidation can be controlled by exposing the pyrite to phosphate under relatively high pH values (pH above 5.0). However, phosphate ceases to function as an inhibitor under lower pHs. The use of two-tail phospholipids instead of phosphate to inhibit the pyrite oxidation proved to be very effective under abiotic conditions. The purpose of the present study is to determine if the use of two-tail phospholipids can be extended to systems that have bacteria present. Batch experiments were conducted in which pyrite slurries were treated with two-tailed lipid either before or after exposure to bacteria. Iron release into the solution was used as a reaction progress variable and Atomic Force Microscopy was used to study the distribution of lipids and bacteria on the pyrite surface. AFM images showed that the formation of 7nm lipid bilayers contributes to the majority of lipid structures on pyrite surface. The bilayers render the pyrite surface hydrophobic and inhibit the reaction of water with the surface, which is known to be a critical reactant. AFM images also showed that phospholipids are capable of displacing a large fraction of bacteria attached to pyrite, reducing the oxidation rate of the mineral. However, addition of heterotrophic bacterial (Acidiphilum acidophilum) to the system resulted in the increase in pyrite oxidation rate again. Cross-linking of the 23:2 dyne phospholipids by exposing the lipid to UV light greatly enhanced the stability of the lipid in the presence of the heterotrophic bacteria. UV pretreated lipid layers reduced pyrite oxidation in the presence of heterotrophic bacteria for up to 30 days. / Chemistry

The demand for biodegradable packaging materials as an alternative to synthetic ones to reduce environmental cost has seen an increase in recent years. In addition, functionalizing the packaging film to provide specific advantages like antimicrobial properties has yet to be explored thoroughly. This study considers adding antimicrobial agents to improve the quality and safety of actively packaged fresh produce using an antimicrobial enzyme (lysozyme) immobilized on a biopolymer based packaging film (corn-zein). The developed packaging material is aimed as an active biodegradable packaging to reduce bacterial contamination on the surface of fresh organic produce, specifically tomatoes. The study uses glutaraldehyde and glyoxal as binding agents to immobilize the enzyme on the packaging film. The effect of concentration of glutaraldehyde and glyoxal on the controlled release of the enzyme was studied. Concentrations of 0.1 and 0.2 g/g lysozyme: cross linking agent had controlled release properties. However, concentrations of 0 or 0.05 are about 20-30% more effective at inactivating bacteria. Antimicrobial activity in the constructed zein films are also tested against selected pathogens (Salmonella Newport and Listeria monocytogenes). Developed zein based film is tested against inoculated tomatoes to determine the efficacy of the films in reducing the pathogen population. The inoculated tomatoes are stored at room temperature over a storage period of one week. The film was able to reduce Listeria monocytogenes population by three logs but was unable to reduce the population of Salmonella Newport. / Master of Science