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Articles 61 - 90 of 230
Full-Text Articles in Physical Sciences and Mathematics
An In Silico Approach To Enzymatic Synthesis Of Fucooligosaccharides Using Α-L-Fucosidase From Thermotoga Maritima, Emmanuel Pérez-Escalante, Luis Guillermo González-Olivares, Araceli Castañeda-Ovando, Alma Elizabeth Cruz-Guerrero, John F. Trant, Wendolyne López-Orozco, Luis Humberto Mendoza-Huizar, Sergio Alatorre-Santamaría
An In Silico Approach To Enzymatic Synthesis Of Fucooligosaccharides Using Α-L-Fucosidase From Thermotoga Maritima, Emmanuel Pérez-Escalante, Luis Guillermo González-Olivares, Araceli Castañeda-Ovando, Alma Elizabeth Cruz-Guerrero, John F. Trant, Wendolyne López-Orozco, Luis Humberto Mendoza-Huizar, Sergio Alatorre-Santamaría
Chemistry and Biochemistry Publications
Abstract: Fucooligosaccharides comprise the primary group of human milk oligosaccharides. Due to their beneficial properties, a series of synthetic methods have been proposed to obtain them. Enzy- matic methods show great promise, and α-L-fucosidase from Thermotoga maritima has emerged as a powerful catalyst for their production. Nonetheless, the enzyme’s limited substrate scope has de- layed its wider application. The present work aims to compare the relative reactivity of fucose, pNP-fucose, and ethyl-fucose, while also exploring the molecular interactions of these fucosyl-donors with the enzyme through a combination DFT and docking analysis. The HOMO-LUMO band gaps range from −7.14571 to −4.24429 …
A Mechanical Mechanism For Vitamin E Acetate In E-Cigarette/Vaping-Associated Lung Injury, Mitchell Dipasquale, Omotayo Gbadamosi, Michael H.L. Nguyen, Stuart R. Castillo, Brett W. Rickeard, Elizabeth G. Kelley, Michihiro Nagao, Drew Marquardt
A Mechanical Mechanism For Vitamin E Acetate In E-Cigarette/Vaping-Associated Lung Injury, Mitchell Dipasquale, Omotayo Gbadamosi, Michael H.L. Nguyen, Stuart R. Castillo, Brett W. Rickeard, Elizabeth G. Kelley, Michihiro Nagao, Drew Marquardt
Chemistry and Biochemistry Publications
Copyright © 2020 American Chemical Society. The outbreak of electronic-cigarette/vaping-Associated lung injury (EVALI) has made thousands ill. This lung injury has been attributed to a physical interaction between toxicants from the vaping solution and the pulmonary surfactant. In particular, studies have implicated vitamin E acetate as a potential instigator of EVALI. Pulmonary surfactant is vital to proper respiration through the mechanical processes of adsorption and interface stability to achieve and maintain low surface tension at the air-liquid interface. Using neutron spin echo spectroscopy, we investigate the impact of vitamin E acetate on the mechanical properties of two lipid-only pulmonary surfactant …
Detecting Mercury (Ii) And Thiocyanate Using “Turn-On” Fluorescence Of Graphene Quantum Dots, Faezeh Askari, Abbas Rahdar, Mohadeseh Dashti, John F. Trant
Detecting Mercury (Ii) And Thiocyanate Using “Turn-On” Fluorescence Of Graphene Quantum Dots, Faezeh Askari, Abbas Rahdar, Mohadeseh Dashti, John F. Trant
Chemistry and Biochemistry Publications
In this work, 1.8 nm graphene quantum dots (GQDs), exhibiting bright blue fluorescence, were prepared using a bottom-up synthesis from citric acid. The fluorescence of the GQDs could be almost completely quenched (about 96%) by adding Hg2+. Quenching was far less efficient with other similar heavy metals, Tl+, Pb2+ and Bi3+. Fluorescence could be near quantitatively restored through the introduction of thiocyanate. This “turn-on” fluorescence can thus be used to detect both or either environmental and physiological contaminants mercury and thiocyanate and could prove useful for the development of simple point-of-care diagnostics in the future. [Figure not available: see fulltext.].
The Synthesis Of Methotrexate-Loaded F127 Microemulsions And Their In Vivo Toxicity In A Rat Model, Abbas Rahdar, Mohammad Reza Hajinezhad, Sarah Nasri, Hamid Beyzaei, Mahmood Barani, John F. Trant
The Synthesis Of Methotrexate-Loaded F127 Microemulsions And Their In Vivo Toxicity In A Rat Model, Abbas Rahdar, Mohammad Reza Hajinezhad, Sarah Nasri, Hamid Beyzaei, Mahmood Barani, John F. Trant
Chemistry and Biochemistry Publications
Methotrexate (MTX) has been often formulated as nano and micro-emulsions, nominally to address its poor solubility and off-target effects. Nanoformulated MTX is universally reported to be a more efficacious anti-cancer agent than direct-dissolved drug; however, these investigations generally fail to screen for in vivo toxicity. This study aims to remedy this oversight. MTX was formulated as a standard Pluronic oil-in-water microemulsion with good drug encapsulation efficiency (73.0% ± 8.4). Preliminary in vitro free radical scavenging studies found that formulation reduces drug oxidation four-fold. The toxic effects of formulated and unformulated MTX were investigated in a Wistar rat model. Rats received …
Cannabinoids And Cannabinoid Receptors: The Story So Far, Fred Shahbazi, Victoria Grandi, Abhinandan Banerjee, John F. Trant
Cannabinoids And Cannabinoid Receptors: The Story So Far, Fred Shahbazi, Victoria Grandi, Abhinandan Banerjee, John F. Trant
Chemistry and Biochemistry Publications
Like most modern molecular biology and natural product chemistry, understanding cannabinoid pharmacology centers around molecular interactions, in this case, between the cannabinoids and their putative targets, the G-protein coupled receptors (GPCRs) cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). Understanding the complex structure and interplay between the partners in this molecular dance is required to understand the mechanism of action of synthetic, endogenous, and phytochemical cannabinoids. This review, with 91 references, surveys our understanding of the structural biology of the cannabinoids and their target receptors including both a critical comparison of the extant crystal structures and the computationally derived …
The Structures Of Polyunsaturated Lipid Bilayers By Joint Refinement Of Neutron And X-Ray Scattering Data, Drew Marquardt, Frederick A. Heberle, Jianjun Pan, Xiaolin Cheng, Georg Pabst, Thad A. Harroun, Norbert Kučerka, John Katsaras
The Structures Of Polyunsaturated Lipid Bilayers By Joint Refinement Of Neutron And X-Ray Scattering Data, Drew Marquardt, Frederick A. Heberle, Jianjun Pan, Xiaolin Cheng, Georg Pabst, Thad A. Harroun, Norbert Kučerka, John Katsaras
Chemistry and Biochemistry Publications
© 2020 Elsevier B.V. We present the detailed structural analysis of polyunsaturated fatty acid-containing phospholipids namely, 1-palmitoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (PDPC) and 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (SDPC). A newly developed molecular dynamics (MD) simulation parsing scheme for lipids containing fatty acids with multiple double bonds was implemented into the scattering density profile (SDP) model to simultaneously refine differently contrasted neutron and X-ray scattering data. SDP analyses of scattering data at 30 °C yielded lipid areas of 71.1 Å2 and 70.4 Å2 for PDPC and SDPC bilayers, respectively, and a model free analysis of PDPC at 30 °C resulted in a lipid area of 72 Å2. In …
Differential Expression Of Glucose Transporters And Hexokinases In Prostate Cancer With A Neuroendocrine Gene Signature: A Mechanistic Perspective For 18 F-Fdg Imaging Of Psma-Suppressed Tumors, Martin K. Bakht, Jessica M. Lovnicki, Janice Tubman, Keith F. Stringer, Jonathan Chiaramonte, Michael R. Reynolds, Iulian Derecichei, Rosa Maria Ferraiuolo, Bre Anne Fifield, Dorota Lubanska, So Won Oh, Gi Jeong Cheon, Cheol Kwak, Chang Wook Jeong, Keon Wook Kang, John F. Trant, Colm Morrissey, Ilsa M. Coleman, Yuzhuo Wang, Hojjat Ahmadzadehfar
Differential Expression Of Glucose Transporters And Hexokinases In Prostate Cancer With A Neuroendocrine Gene Signature: A Mechanistic Perspective For 18 F-Fdg Imaging Of Psma-Suppressed Tumors, Martin K. Bakht, Jessica M. Lovnicki, Janice Tubman, Keith F. Stringer, Jonathan Chiaramonte, Michael R. Reynolds, Iulian Derecichei, Rosa Maria Ferraiuolo, Bre Anne Fifield, Dorota Lubanska, So Won Oh, Gi Jeong Cheon, Cheol Kwak, Chang Wook Jeong, Keon Wook Kang, John F. Trant, Colm Morrissey, Ilsa M. Coleman, Yuzhuo Wang, Hojjat Ahmadzadehfar
Chemistry and Biochemistry Publications
Although the incidence of de novo neuroendocrine prostate cancer (PC) is rare, recent data suggest that low expression of prostatespecific membrane antigen (PSMA) is associated with a spectrum of neuroendocrine hallmarks and androgen receptor (AR) suppression in PC. Previous clinical reports indicate that PCs with a phenotype similar to neuroendocrine tumors can be more amenable to imaging by 18F-FDG than by PSMA-targeting radioligands. In this study, we evaluated the association between neuroendocrine gene signature and 18F-FDG uptake-associated genes including glucose transporters (GLUTs) and hexokinases, with the goal of providing a genomic signature to explain the reported 18F-FDG avidity of PSMA …
Stretchable Ultrasheer Fabrics As Semitransparent Electrodes For Wearable Light-Emitting E-Textiles With Changeable Display Patterns, Yunyun Wu, Sara S. Mechael, Cecilia Lerma, R. Stephen Carmichael, Tricia Breen Carmichael
Stretchable Ultrasheer Fabrics As Semitransparent Electrodes For Wearable Light-Emitting E-Textiles With Changeable Display Patterns, Yunyun Wu, Sara S. Mechael, Cecilia Lerma, R. Stephen Carmichael, Tricia Breen Carmichael
Chemistry and Biochemistry Publications
Despite the development throughout human history of a wealth of textile materials and structures, the porous structures and non-planar surfaces of textiles are often viewed as problematic for the fabrication of wearable e-textiles and smart clothing. Here, we demonstrate a new textile-centric design paradigm in which we use the textile structure as an integral part of wearable device design. We coat the open framework structure of an ultrasheer knitted textile with a conformal gold film using solution-based metallization to form gold-coated ultrasheer electrodes that are highly conductive (3.6 ± 0.9 Ω/sq) and retain conductivity to 200% strain with R/R0 < 2. The ultrasheer electrodes produce wearable, highly stretchable light-emitting e-textiles that function to 200% strain. Stencil printing a wax resist provides patterned electrodes for patterned light emission; furthermore, incorporating soft-contact lamination produces light-emitting textiles that exhibit, for the first time, readily changeable patterns of illumination.
Transverse Lipid Organization Dictates Bending Fluctuations In Model Plasma Membranes, Brett W. Rickeard, Michael H.L. Nguyen, Mitchell Dipasquale, Caesar G. Yip, Hamilton Baker, Frederick A. Heberle, Xiaobing Zuo, Elizabeth G. Kelley, Michihiro Nagao, Drew Marquardt
Transverse Lipid Organization Dictates Bending Fluctuations In Model Plasma Membranes, Brett W. Rickeard, Michael H.L. Nguyen, Mitchell Dipasquale, Caesar G. Yip, Hamilton Baker, Frederick A. Heberle, Xiaobing Zuo, Elizabeth G. Kelley, Michihiro Nagao, Drew Marquardt
Chemistry and Biochemistry Publications
© 2020 The Royal Society of Chemistry. Membrane undulations play a vital role in many biological processes, including the regulation of membrane protein activity. The asymmetric lipid composition of most biological membranes complicates theoretical description of these bending fluctuations, yet experimental data that would inform any such a theory is scarce. Here, we used neutron spin-echo (NSE) spectroscopy to measure the bending fluctuations of large unilamellar vesicles (LUV) having an asymmetric transbilayer distribution of high- and low-melting lipids. The asymmetric vesicles were prepared using cyclodextrin-mediated lipid exchange, and were composed of an outer leaflet enriched in egg sphingomyelin (ESM) and …
The Antioxidant Vitamin E As A Membrane Raft Modulator: Tocopherols Do Not Abolish Lipid Domains, Mitchell Dipasquale, Michael H.L. Nguyen, Brett W. Rickeard, Nicole Cesca, Christopher Tannous, Stuart R. Castillo, John Katsaras, Elizabeth G. Kelley, Frederick A. Heberle, Drew Marquardt
The Antioxidant Vitamin E As A Membrane Raft Modulator: Tocopherols Do Not Abolish Lipid Domains, Mitchell Dipasquale, Michael H.L. Nguyen, Brett W. Rickeard, Nicole Cesca, Christopher Tannous, Stuart R. Castillo, John Katsaras, Elizabeth G. Kelley, Frederick A. Heberle, Drew Marquardt
Chemistry and Biochemistry Publications
© 2020 Elsevier B.V. The antioxidant vitamin E is a commonly used vitamin supplement. Although the multi-billion dollar vitamin and nutritional supplement industry encourages the use of vitamin E, there is very little evidence supporting its actual health benefits. Moreover, vitamin E is now marketed as a lipid raft destabilizing anti-cancer agent, in addition to its antioxidant behaviour. Here, we studied the influence of vitamin E and some of its vitamers on membrane raft stability using phase separating unilamellar lipid vesicles in conjunction with small-angle scattering techniques and fluorescence microscopy. We find that lipid phase behaviour remains unperturbed well beyond …
A Review And Critique Of Academic Lab Safety Research, A. Dana Ménard, John F. Trant
A Review And Critique Of Academic Lab Safety Research, A. Dana Ménard, John F. Trant
Chemistry and Biochemistry Publications
Over the past ten years, there have been several high-profile accidents in academic laboratories around the world, resulting in significant injuries and fatalities. The aftermath of these incidents is often characterized by calls for reflection and re-examination of the academic discipline’s approach to safety research and policy. However, the study of academic lab safety is still underdeveloped and necessary data about changes in safety attitudes and behaviours has not been gathered. This Review article critically examines the state of academic chemical safety research from a multifactorial stance, including research on the occurrence of lab accidents, contributors to lab accidents, the …
Response Time And Eye Tracking Datasets For Activities Demanding Varying Cognitive Load, Prarthana Pillai, Prathamesh Ayare, Balakumar Balasingam, Kevin Milne, Francesco Biondi
Response Time And Eye Tracking Datasets For Activities Demanding Varying Cognitive Load, Prarthana Pillai, Prathamesh Ayare, Balakumar Balasingam, Kevin Milne, Francesco Biondi
Human Kinetics Publications
The dataset contains the following three measures that are widely used to determine cognitive load in humans: Detection Response Task - response time, pupil diameter, and eye gaze. These measures were recorded from 28 participants while they underwent tasks that are designed to permeate three different cognitive difficulty levels. The dataset will be useful to those researchers who seek to employ low cost, non-invasive sensors to detect cognitive load in humans and to develop algorithms for human-system automation. One such application is found in Advanced Driver Assistance Systems where eye-trackers are employed to monitor the alertness of the drivers. The …
Photophysical And Optical Properties Of Semiconducting Polymer Nanoparticles Prepared From Hyaluronic Acid And Polysorbate 80, Adam Langlois, Gage T. Mason, Michael H.L. Nguyen, Mehdi Rezapour, Paul Ludovic Karsenti, Drew Marquardt, Simon Rondeau-Gagné
Photophysical And Optical Properties Of Semiconducting Polymer Nanoparticles Prepared From Hyaluronic Acid And Polysorbate 80, Adam Langlois, Gage T. Mason, Michael H.L. Nguyen, Mehdi Rezapour, Paul Ludovic Karsenti, Drew Marquardt, Simon Rondeau-Gagné
Chemistry and Biochemistry Publications
Copyright © 2019 American Chemical Society. A nanoprecipitation procedure was utilized to prepare novel diketopyrrolopyrrole-based semiconducting polymer nanoparticles (SPNs) with hyaluronic acid (HA) and polysorbate 80. The nanoprecipitation led to the formation of spherical nanoparticles with average diameters ranging from 100 to 200 nm, and a careful control over the structure of the parent conjugated polymers was performed to probe the influence of π-conjugation on the final photophysical and thermal stability of the resulting SPNs. Upon generation of a series of novel SPNs, the optical and photophysical properties of the new nanomaterials were probed in solution using various techniques including …
Covalently Functionalized Sawdust For The Remediation Of Phosphate From Agricultural Wastewater, Daniel Meister, David Ure, Angela Awada, Jean-Claude Barrette, Joel Gagnon, Bluent Mutus, John F. Trant
Covalently Functionalized Sawdust For The Remediation Of Phosphate From Agricultural Wastewater, Daniel Meister, David Ure, Angela Awada, Jean-Claude Barrette, Joel Gagnon, Bluent Mutus, John F. Trant
Chemistry and Biochemistry Publications
Phosphate remediation from wastewater is rapidly becoming an ever more attractive process due to a combination of both the economic pressure of increasing phosphate scarcity and the environmental damage caused by untreated agricultural runoff. Ideally, remediated phosphate will be recoverable and would be able to be reused as fertilizer. Many different resins have been investigated, but due to the scale of the challenge, any feasible solution will involve the use of very inexpensive waste products as the solid support. Sawdust, functionalized with iron-binding ligands, is such a potential resin. Sawdust alone binds 0.3 g/kg of phosphate which is insufficient. Iron …
Peptide-Induced Lipid Flip-Flop In Asymmetric Liposomes Measured By Small Angle Neutron Scattering, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Milka Doktorova, Frederick A. Heberle, Haden L. Scott, Francisco N. Barrera, Graham Taylor, Charles P. Collier, Christopher B. Stanley, John Katsaras, Drew Marquardt
Peptide-Induced Lipid Flip-Flop In Asymmetric Liposomes Measured By Small Angle Neutron Scattering, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Milka Doktorova, Frederick A. Heberle, Haden L. Scott, Francisco N. Barrera, Graham Taylor, Charles P. Collier, Christopher B. Stanley, John Katsaras, Drew Marquardt
Chemistry and Biochemistry Publications
© 2019 American Chemical Society. Despite the prevalence of lipid transbilayer asymmetry in natural plasma membranes, most biomimetic model membranes studied are symmetric. Recent advances have helped to overcome the difficulties in preparing asymmetric liposomes in vitro, allowing for the examination of a larger set of relevant biophysical questions. Here, we investigate the stability of asymmetric bilayers by measuring lipid flip-flop with time-resolved small-angle neutron scattering (SANS). Asymmetric large unilamellar vesicles with inner bilayer leaflets containing predominantly 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and outer leaflets composed mainly of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) displayed slow spontaneous flip-flop at 37 -C (half-time, t1/2 = 140 h). However, …
Neuro And Hepatic Toxicological Profile Of (S)-2,4-Diaminobutanoic Acid In Embryonic, Adolescent And Adult Zebrafish, Rosa-Maria Ferraiuolo, Daniel Meister, Dominique Leckie, Jonathan Franke, Lisa A. Porter, John F. Trant
Neuro And Hepatic Toxicological Profile Of (S)-2,4-Diaminobutanoic Acid In Embryonic, Adolescent And Adult Zebrafish, Rosa-Maria Ferraiuolo, Daniel Meister, Dominique Leckie, Jonathan Franke, Lisa A. Porter, John F. Trant
Chemistry and Biochemistry Publications
(S)-2,4-Diaminobutanoic acid (DABA) is a noncanonical amino acid often co-produced by cyanobacteria along with β-N-methylamino-l-alanine (BMAA) in algal blooms. Although BMAA is a well-established neurotoxin, the toxicity of DABA remains unclear. As part of our development of biocompatible materials, we wish to make use of DABA as both a building block and as the end-product of enzymatically-induced depolymerization; however, if it is toxic at very low concentrations, this would not be possible. We examined the toxicity of DABA using both in vivo embryonic and adult zebrafish models. At higher sub-lethal concentrations (700 µM), the fish demonstrated early …
Calcium-Ion Batteries: Identifying Ideal Electrolytes For Next-Generation Energy Storage Using Computational Analysis, Mehdi Shakourian-Fard, Ganesh Kamath, S. Maryamdokht Taimoory, John F. Trant
Calcium-Ion Batteries: Identifying Ideal Electrolytes For Next-Generation Energy Storage Using Computational Analysis, Mehdi Shakourian-Fard, Ganesh Kamath, S. Maryamdokht Taimoory, John F. Trant
Chemistry and Biochemistry Publications
Calcium ion batteries show promise as a high-density, next generation replacement for current lithium ion batteries. The precise chemical structure of the carbonate electrolyte solvent has a large impact on calcium battery efficacy. In this computational study, we have investigated the solvation behavior of calcium tetrafluoroborate in both neat carbonates and carbonate mixtures using combined molecular dynamics simulations and quantum mechanical calculations. Our results indicate that both neat ethyl methyl carbonate and a mixture of ethylene carbonate and diethyl carbonate show the highest free-energy of solvation for the Ca2+ ion, making them likely candidates for further focus. The cation’s …
Halogen Bonding And Host–Guest Chemistry Between N-Alkylammonium Resorcinarene Halides, Diiodoperfluorobutane And Neutral Guests, Fangfang Pan, Mohadeseh Dashti, Michael R. Reynolds, Kari Rissanen, John F. Trant, Ngong Kodiah Beyeh
Halogen Bonding And Host–Guest Chemistry Between N-Alkylammonium Resorcinarene Halides, Diiodoperfluorobutane And Neutral Guests, Fangfang Pan, Mohadeseh Dashti, Michael R. Reynolds, Kari Rissanen, John F. Trant, Ngong Kodiah Beyeh
Chemistry and Biochemistry Publications
Single crystal X-ray structures of halogen-bonded assemblies formed between host N-hexylammonium resorcinarene bromide (1) or N-cyclohexylammonium resorcinarene chloride (2), and 1,4-diiodooctafluorobutane and accompanying small solvent guests (meth- anol, acetonitrile and water) are presented. The guests’ inclusion affects the geometry of the cavity of the receptors 1 and 2, while the divalent halogen bond donor 1,4-diiodooctafluorobutane determines the overall nature of the halogen bond assembly. The crystal lattice of 1 contains two structurally different dimeric assemblies A and B, formally resulting in the mixture of a capsular dimer and a dimeric pseudo-capsule. 1H …
Adsorption Of Bovine Serum Albumin (Bsa) By Bare Magnetite Nanoparticles With Surface Oxidative Impurities That Prevent Aggregation, Somayeh Rahdar, Abbas Rahdar, Shahin Ahmadi, John F. Trant
Adsorption Of Bovine Serum Albumin (Bsa) By Bare Magnetite Nanoparticles With Surface Oxidative Impurities That Prevent Aggregation, Somayeh Rahdar, Abbas Rahdar, Shahin Ahmadi, John F. Trant
Chemistry and Biochemistry Publications
Bare, uncoated magnetite nanoparticles, synthesized using an electrochemical surfactant-free synthesis, have highly oxidized surfaces that prevent aggregation. These particles have demonstrated highly intriguing biological activity showing extremely potent antibiotic activity against both gram-positive and gram-negative bacteria with little toxicity to rats. This difference in activity could be ascribed to the nature of the protein corona. In this study the kinetics and thermodynamics of the binding of bovine serum albumin, used as a model serum protein, to these magnetite nanoparticles was analyzed. There is no significant change in particle diameter by dynamic light scattering following adsorption indicating corona formation does not …
Methanol Accelerates Dmpc Flip-Flop And Transfer: A Sans Study On Lipid Dynamics, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Christopher B. Stanley, Elizabeth G. Kelley, Drew Marquardt
Methanol Accelerates Dmpc Flip-Flop And Transfer: A Sans Study On Lipid Dynamics, Michael H.L. Nguyen, Mitchell Dipasquale, Brett W. Rickeard, Christopher B. Stanley, Elizabeth G. Kelley, Drew Marquardt
Chemistry and Biochemistry Publications
© 2019 Biophysical Society Methanol is a common solubilizing agent used to study transmembrane proteins/peptides in biological and synthetic membranes. Using small angle neutron scattering and a strategic contrast-matching scheme, we show that methanol has a major impact on lipid dynamics. Under increasing methanol concentrations, isotopically distinct 1,2-dimyristoyl-sn-glycero-3-phosphocholine large unilamellar vesicle populations exhibit increased mixing. Specifically, 1,2-dimyristoyl-sn-glycero-3-phosphocholine transfer and flip-flop kinetics display linear and exponential rate enhancements, respectively. Ultimately, methanol is capable of influencing the structure-function relationship associated with bilayer composition (e.g., lipid asymmetry). The use of methanol as a carrier solvent, despite better simulating some biological conditions (e.g., antimicrobial …
Gramicidin Increases Lipid Flip-Flop In Symmetric And Asymmetric Lipid Vesicles, Milka Doktorova, Frederick A. Heberle, Drew Marquardt, Radda Rusinova, R. Lea Sanford, Thasin A. Peyear, John Katsaras, Gerald W. Feigenson, Harel Weinstein, Olaf S. Andersen
Gramicidin Increases Lipid Flip-Flop In Symmetric And Asymmetric Lipid Vesicles, Milka Doktorova, Frederick A. Heberle, Drew Marquardt, Radda Rusinova, R. Lea Sanford, Thasin A. Peyear, John Katsaras, Gerald W. Feigenson, Harel Weinstein, Olaf S. Andersen
Chemistry and Biochemistry Publications
© 2019 Biophysical Society Unlike most transmembrane proteins, phospholipids can migrate from one leaflet of the membrane to the other. Because this spontaneous lipid translocation (flip-flop) tends to be very slow, cells facilitate the process with enzymes that catalyze the transmembrane movement and thereby regulate the transbilayer lipid distribution. Nonenzymatic membrane-spanning proteins with unrelated primary functions have also been found to accelerate lipid flip-flop in a nonspecific manner and by various hypothesized mechanisms. Using deuterated phospholipids, we examined the acceleration of flip-flop by gramicidin channels, which have well-defined structures and known functions, features that make them ideal candidates for probing …
A H2ax–Carp-1 Interaction Regulates Apoptosis Signaling Following Dna Damage, Sreeja C. Sekhar, Jaganathan Venkatesh, Vino T. Cheriyan, Magesh Muthu, Edi Levi, Hadeel Assad, Paul Meister, Vishnu V. Undyala, James W. Gauld, Arun K. Rishi
A H2ax–Carp-1 Interaction Regulates Apoptosis Signaling Following Dna Damage, Sreeja C. Sekhar, Jaganathan Venkatesh, Vino T. Cheriyan, Magesh Muthu, Edi Levi, Hadeel Assad, Paul Meister, Vishnu V. Undyala, James W. Gauld, Arun K. Rishi
Chemistry and Biochemistry Publications
Cell Cycle and Apoptosis Regulatory Protein (CARP-1/CCAR1) is a peri-nuclear phosphoprotein that regulates apoptosis via chemotherapeutic Adriamycin (doxorubicin) and a novel class of CARP-1 functional mimetic (CFM) compounds. Although Adriamycin causes DNA damage, data from Comet assays revealed that CFM-4.16 also induced DNA damage. Phosphorylation of histone 2AX (γH2AX) protein is involved in regulating DNA damage repair and apoptosis signaling. Adriamycin or CFM-4.16 treatments inhibited cell growth and caused elevated CARP-1 and γH2AX in human breast (HBC) and cervical cancer (HeLa) cells. In fact, a robust nuclear or peri-nuclear co-localization of CARP-1 and γH2AX occurred in cells undergoing apoptosis. Knock-down …
L-Tryptophan Adsorption Differentially Changes The Optical Behaviour Of Pseudo-Enantiomeric Cysteine-Functionalized Quantum Dots: Towards Chiral Fluorescent Biosensors, Faezeh Askari, Abbas Rahdar, John F. Trant
L-Tryptophan Adsorption Differentially Changes The Optical Behaviour Of Pseudo-Enantiomeric Cysteine-Functionalized Quantum Dots: Towards Chiral Fluorescent Biosensors, Faezeh Askari, Abbas Rahdar, John F. Trant
Chemistry and Biochemistry Publications
Water-soluble chiral graphene quantum dots (GQDs) with a strong blue emission were synthesized by covalently immobilizing l-cysteine or d-cysteine onto the GQDs. Either the amine or the thiol group of cysteine was used to make the bond through amide coupling or thiol-ene click chemistry respectively. The functionalized chiral GQDs were the characterized by FT-IR and UV–vis. The enantiomeric pairs exhibit equal but opposite bands in circular dichroism spectra suggesting that there is no difference in the efficacy of conjugation. The fluorescent response of these chiral GQDs when exposed to l-tryptophan was then studied. The fluorescence of the amide-conjugated GQDs was …
Synthesis, Physical Characterization, Antifungal And Antibacterial Activity Of Oleic Acid-Capped Nanomagnetite And Cobalt-Doped Nanomagnetite, Abbas Rahdar, Hamid Beyzaei, Mohsen Saadat, Xiao Yu, John F. Trant
Synthesis, Physical Characterization, Antifungal And Antibacterial Activity Of Oleic Acid-Capped Nanomagnetite And Cobalt-Doped Nanomagnetite, Abbas Rahdar, Hamid Beyzaei, Mohsen Saadat, Xiao Yu, John F. Trant
Chemistry and Biochemistry Publications
Nanoparticles, 10-14 nm, consisting of either Fe3O4 or Co0.2Fe2.8O4 stabilized with oleic acid, were prepared using solution combustion. Their structural and magnetic properties were examined using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry, and Fourier-transform infrared spectroscopy. The properties of both sets of materials are similar except the cobalt-doped particles are considerably less magnetic. The in vitro inhibitory activities of the nanoparticles were assessed against pathogenic bacteria Shigella dysenteriae, Klebsiella pneumoniae, Acinetobacter baumannii, Streptococcus pyogenes, and pathogenic fungi and molds Candida albicans, Fusarium oxysporum and Aspergillus …
Unnatural Amino Acids Improve Affinity And Modulate Immunogenicity: Developing Peptides To Treat Mhc Type Ii Autoimmune Disorders, Daniel Meister, S. Maryamdokht Taimoory, John F. Trant
Unnatural Amino Acids Improve Affinity And Modulate Immunogenicity: Developing Peptides To Treat Mhc Type Ii Autoimmune Disorders, Daniel Meister, S. Maryamdokht Taimoory, John F. Trant
Chemistry and Biochemistry Publications
Many autoimmune diseases, including multiple sclerosis (MS), rheumatoid arthritis (RA), and celiac disease (CD), arise from improper immune system recognition of self or benign peptides as threats. No autoimmune disease currently has a cure. Many treatments suppress the entire immune system to decrease symptom severity. The core molecular interaction underlying these diseases involves specific alleles of the human leukocyte antigen (HLA) receptor hosting the immunodominant peptides associated with the disease (i.e. myelin basic protein, Type II collagen, or α-gliadin) in their binding groove. Once bound, circulating T-cells can recognize the HLA-antigen complex and initiate the complex cascade that forms an …
Chapter 3: The Behaviour Of Vitamin E In Membranes, J. Atkinson, D. Marquardt, T. Harroun
Chapter 3: The Behaviour Of Vitamin E In Membranes, J. Atkinson, D. Marquardt, T. Harroun
Chemistry and Biochemistry Publications
© 2019 The Royal Society of Chemistry. The neutral lipids of the vitamin E family (tocopherols and tocotrienols) are well known antioxidants with -tocopherol (-Toc) being the sole tocopherol retained in mammalian tissues after absorption from the diet. Because of their high hydrophobicity, tocopherols partition easily into biological membranes. The location and dynamic behavior of tocopherols and tocotrienols in phospholipid membranes is essential information for describing the mechanism(s) of action of these molecules. The bilayer orientation and dynamics are central to our comprehension of their action as antioxidants, protecting free radical-induced peroxidation of polyunsaturated phospholipids. Tocopherols and tocotrienols may also …
Vitamin E-Inspired Multi-Scale Imaging Agent, Mikel Ghelfi, Lucas A. Maddalena, Jeffrey A. Stuart, Jeffrey Atkinson, Thad A. Harroun, Drew Marquardt
Vitamin E-Inspired Multi-Scale Imaging Agent, Mikel Ghelfi, Lucas A. Maddalena, Jeffrey A. Stuart, Jeffrey Atkinson, Thad A. Harroun, Drew Marquardt
Chemistry and Biochemistry Publications
© 2018 Elsevier Ltd The production and use of multi-modal imaging agents is on the rise. The vast majority of these imaging agents are limited to a single length scale for the agent (e.g. tissues only), which is typically at the organ or tissue scale. This work explores the synthesis of such an imaging agent and discusses the applications of our vitamin E-inspired multi-modal and multi-length scale imaging agents TB-Toc ((S,E)-5,5-difluoro-7-(2-(5-((6-hydroxy-2,5,7,8-tetramethylchroman-2-yl) methyl) thiophen-2-yl) vinyl)-9-methyl-5H-dipyrrolo-[1,2-c:2’,1’-f][1,3,2]diazaborinin-4-ium-5-uide). We investigate the toxicity of TB-Toc along with the starting materials and lipid based delivery vehicle in mouse myoblasts and fibroblasts. Further we investigate the uptake …
Recent Advances In The Application Of Carbohydrates As Renewable Feedstocks For The Synthesis Of Nitrogen-Containing Compounds, S. Iraj Sadraei, Brent St Onge, John F. Trant
Recent Advances In The Application Of Carbohydrates As Renewable Feedstocks For The Synthesis Of Nitrogen-Containing Compounds, S. Iraj Sadraei, Brent St Onge, John F. Trant
Chemistry and Biochemistry Publications
Carbohydrates, in the form of chitin, chitosan and cellulose, are one of the most available, renewable, and sustainable chemical feedstocks. Their conversion to biofuels, fine chemicals, and industrially-relevant monomers is becoming increasingly viable and promising as innovation decreases the price of this technology, and climate change and the price of fossil fuels increases the social and economic costs of using traditional feedstocks. In recent years, carbohydrates have been increasingly used as sources for nitrogen-containing fine chemicals. This chapter, with 86 references, provides a brief overview of the conversion of carbohydrate biomass to the standard hydrocarbon and oxygen-containing derivatives, and then …
An Assessment Of Computational Methods For Calculating Accurate Structures And Energies Of Bio-Relevant Polysulfur/Selenium-Containing Compounds, Sahar Nikoo, Paul Meister, John Hayward, James Gauld
An Assessment Of Computational Methods For Calculating Accurate Structures And Energies Of Bio-Relevant Polysulfur/Selenium-Containing Compounds, Sahar Nikoo, Paul Meister, John Hayward, James Gauld
Chemistry and Biochemistry Publications
The heavier chalcogens sulfur and selenium are important in organic and inorganic chemistry, and the role of such chalcogens in biological systems has recently gained more attention. Sulfur and, to a lesser extent selenium, are involved in diverse reactions from redox signaling to antioxidant activity and are considered essential nutrients. We investigated the ability of the DFT functionals (B3LYP, B3PW91, ωB97XD, M06-2X, and M08-HX) relative to electron correlation methods MP2 and QCISD to produce reliable and accurate structures as well as thermochemical data for sulfur/selenium-containing systems. Bond lengths, proton affinities (PA), gas phase basicities (GPB), chalcogen–chalcogen bond dissociation enthalpies (BDE), …
Computational, Experimental Details, And Biological Raw Data Accompanying The Publication: “The Synthesis And Characterization Of A Nanomagnetite With Potent Antibacterial Activity And Low Mammalian Toxicity”, Seyedeh Maryamdokht Taimoory, Abbas Rahdar, Mousa Aliahmad, Fardin Sadeghfar, Mohammad Reza Hajinezhad, Mohammad Jahantigh, Parisa Shahbazi, John F. Trant
Computational, Experimental Details, And Biological Raw Data Accompanying The Publication: “The Synthesis And Characterization Of A Nanomagnetite With Potent Antibacterial Activity And Low Mammalian Toxicity”, Seyedeh Maryamdokht Taimoory, Abbas Rahdar, Mousa Aliahmad, Fardin Sadeghfar, Mohammad Reza Hajinezhad, Mohammad Jahantigh, Parisa Shahbazi, John F. Trant
Chemistry and Biochemistry Publications
This data file includes experimental details on how to make uncoated iron oxide nanoparticles using a green electrochemical method. It provides the raw data on the antibacterial activity of one of these formulations, and the full computational data and methodology used to generate that data, of several different magnetite clusters of specific spin multiplicities for 4, 5, 7 and 9 iron atom magnetite clusters. This data will assist other researchers wishing to replicate or expand on these results for the investigation and use of nanomagnetite for antibacterial applications.