Browsing by Subject "Diglycerides"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Differential sensing of hydrophobic analytes with serum albumins(2012-05) Ivy, Michelle Adams; Anslyn, Eric V., 1960-In the last decade, there has been a growing interest in the use of differential sensing for molecular recognition. Inspired by the mammalian olfactory system, differential sensing employs an array of non-selective receptors, which through cross-reactive interactions, create a distinct pattern for each analyte tested. The unique fingerprints obtained for each analyte with differential sensing are studied with statistical analysis techniques, such as principal component analysis and linear discriminant analysis. It was postulated that serum albumin proteins would be applicable to differential sensing schemes due to significant differences in sequence identity between different serum albumin species, and due to the wide range of hydrophobic molecules which are known to bind to these proteins. Consequently, cross-reactive serum albumin arrays were developed, utilizing hydrophobic fluorescent indicators to detect hydrophobic molecules. As such, serum albumin cross-reactive arrays were employed to discriminate subtly different hydrophobic analytes, and mixtures of these analytes, in the form of terpenes and perfumes, plasticizers and plastic explosive mixtures, and glycerides and adipocyte extracts. In this doctoral work, a detailed review of the field of differential sensing, and a thorough study of principal component analysis and linear discriminant analysis in various differential sensing scenarios, are given. These introductory chapters aid in better understanding the methods and techniques applied in later experimental chapters. In chapter 3, serum albumins, a PRODAN indicator, and an additive are shown to discriminate five terpene analytes and terpene doped perfumes. Chapter 4 describes an array with serum albumins, two dansyl fluorophores, and an additive which successfully differentiate the plasticizers found within the plastic explosives C4 and Semtex and simulated C4 and Semtex mixtures. Discrimination of these simulated mixtures was also achieved with this array in the presence of soil contaminants, demonstrating the potential real-world applicability of this sensing ensemble. Finally, chapter 5 details an array consisting of serum albumins, several fluorescent indicators, and a Grubb's olefin metathesis reaction, to differentiate saturated and unsaturated triglycerides, diglycerides, and monoglycerides. Mixtures of glycerides in adipocyte extracts taken from rats with different health states were then successfully discriminated, showing promise for clinical applications in differentiating adipoctyes from pre-diabetic, type 2 diabetic, and non-diabetic individuals.Item Study of lipid raft domains using computer simulation techniques(2012-05) Alwarawrah, Mohammad; Huang, Juyang; Cheng, Kelvin K.; Sanati, Mahdi; Khare, RajeshThe cholesterol condensing effect in DOPC bilayer was investigated via atomistic molecular dynamics (MD) simulation. The calculated partial-specific areas of lipids in DOPC/cholesterol lipid bilayer clearly show the condensing effect of cholesterol. The results showed that the total area of a PC/cholesterol bilayer is primarily determined by the molecular packing in the cholesterol sterol ring region. An alternative analysis of area per molecule within this region is proposed, which takes into account the cholesterol tilt angle and the practical incompressibility of cholesterol sterol rings. The new calculation shows that the majority of the area lost due to the cholesterol condensing effect is taken from PC molecules. MD simulation was also used to study the interactions between DAG, POPC, and cholesterol. Our results show that both DAG and cholesterol produce some very similar effects in POPC bilayers: increasing acyl chain order and bilayer thickness, reducing volume-per-lipid, and decreasing lateral diffusion of molecules. More significantly, DAG also produces a strong “condensing effect” in PC bilayers. In comparison, cholesterol is more effective than DAG in producing the above effects. Interestingly, our simulations also show that the largest spacing usually occurs between the first and the second nearest-neighbor PC headgroups from a DAG due to the umbrella effect. In another studies, the docking of PKCα-C1 and PKCβ-C2 domains to POPC/POPS/POG lipid bilayers were investigated using MD simulation. In the systems that contain PKCα-C1 domain, the domain only docks to a lipid bilayer that contains POG. This docking is accommodated with significant conformational changes in the PKCα-C1 domain structure. The docking of PKCα-C1 domain to lipid bilayers containing POG shows a high specificity of PKCα-C1 domain toward diacylglycerol. On the other hand, the PKCβ-C2 domain adapts a parallel configuration when it docks to the lipid bilayer in the absence of POG; however, at the presence of POG, it adapts a perpendicular configuration. Furthermore, PKCβ-C2 domain shows no significant conformational change during the docking, which agrees with the experimental studies.