Mark Young

Publications of Mark Young

• Selective killing of Aggregatibacter actinomycetemcomitans by ciprofloxacin during development of a dual species biofilm with Streptococcus sanguinis.

  Authors: Peter Suci, Mark Young

  Archives of oral biology. 04/2011; 56(10):1055-63.

  Periodontal disease is associated with a pathogen-induced transition to a chronic destructive inflammatory response. Since commensals may either passively or actively contribute to immunePeriodontal disease is associated with a pathogen-induced transition to a chronic destructive inflammatory response. Since commensals may either passively or actively contribute to immune homeostasis, therapies aimed at selectively reducing the competitive advantage of pathogens may be effective supplements to traditional methods. We developed an in vitro system to grow biofilms composed of the pathogen (Aggregatibacter actinomycetemcomitans) and the commensal (Streptococcus sanguinis). We used the biofilm model to determine the feasibility of selectively killing the pathogen using the fluoroquinolone, ciprofloxacin. Biofilms were exposed to relevant ciprofloxacin doses during the first 24h of development, with subsequent removal of the ciprofloxacin for a 24h period. Biofilm growth was assessed by confocal laser scanning microscopy, crystal violet staining and DNA abundance. Exposure to 0.01mg/L or 0.5mg/L ciprofloxacin significantly reduced the microcolony size and cell surface density of A. actinomycetemcomitans in the dual species biofilm over a 24h period whilst allowing uninhibited S. sanguinis biofilm formation. A. actinomycetemcomitans biofilm development was insignificant over a subsequent 24h period after removal of the ciprofloxacin indicating that A. actinomycetemcomitans cells were killed. A. actinomycetemcomitans residing in a dual species biofilm with the commensal, S. sanguinis can be selectively killed, or at least rendered metabolically inactive, by treatment with ciprofloxacin. The dual species biofilm model will be a useful tool for designing in vivo studies to determine the efficacy of selective killing agents as an adjunct treatment of localized aggressive forms of periodontal disease.

• Monitoring structural transitions in icosahedral virus protein cages by site-directed spin labeling.

  Authors: Robert J Usselman, Eric D Walter, Debbie Willits, Trevor Douglas, Mark Young, David J Singel

  Journal of the American Chemical Society. 03/2011; 133(12):4156-9.

  This work describes an approach for calculating and measuring dipolar interactions in multispin systems to monitor conformational changes in icosahedral protein cages using site-directed spinThis work describes an approach for calculating and measuring dipolar interactions in multispin systems to monitor conformational changes in icosahedral protein cages using site-directed spin labeling. Cowpea chlorotic mottle virus (CCMV) is used as a template that undergoes a pH-dependent reversible capsid expansion wherein the protein cage swells by 10%. The sequence-position-dependent geometric presentation of attached spin-label groups provides a strategy for targeting amino acid residues most probative of structural change. The labeled protein cage residues and structural transition were found to affect the local mobility and dipolar interactions of the spin label, respectively. Line-shape changes provided a spectral signature that could be used to follow the conformational change in CCMV coat dynamics. The results provide evidence for a concerted swelling process in which the cages exist in only two structural forms, with essentially no intermediates. This methodology can be generalized for all symmetry types of icosahedral protein architectures to monitor protein cage dynamics.

• Two-component magnetic structure of iron oxide nanoparticles mineralized in Listeria innocua protein cages

  Authors: Robert J. Usselman, Michael T. Klem, Stephen E. Russek, Mark Young, Trevor Douglas, Ron B. Goldfarb

  Journal of Applied Physics. 07/2010;

  Magnetometry was used to determine the magnetic properties of maghemite (γ -Fe ₂ O ₃) nanoparticles formed within Listeria innocua protein cage. The electron magnetic resonanceMagnetometry was used to determine the magnetic properties of maghemite (γ -Fe ₂ O ₃) nanoparticles formed within Listeria innocua protein cage. The electron magnetic resonance spectrum shows the presence of at least two magnetization components. The magnetization curves are explained by a sum of two Langevin functions in which each filled protein cage contains both a large magnetic iron oxide core plus an amorphous surface consisting of small noncoupled iron oxide spin clusters. This model qualitatively explains the observed decrease in the temperature dependent saturation moment and removes an unrealistic temperature dependent increase in the particle moment often observed in nanoparticle magnetization measurements.

• Targeted delivery of a photosensitizer to Aggregatibacter actinomycetemcomitans biofilm.

  Authors: Peter Suci, Sebyung Kang, Rudolf Gmür, Trevor Douglas, Mark Young

  Antimicrobial agents and chemotherapy. 04/2010; 54(6):2489-96.

  The ability to selectively target specific biofilm species with antimicrobials would enable control over biofilm consortium composition, with medical applications in treatment of infections onThe ability to selectively target specific biofilm species with antimicrobials would enable control over biofilm consortium composition, with medical applications in treatment of infections on mucosal surfaces that are colonized by a mixture of beneficial and pathogenic microorganisms. We functionalized a genetically engineered multimeric protein with both a targeting moiety (biotin) and either a fluorophore or a photosensitizer (SnCe6). Biofilm microcolonies of Aggregatibacter actinomycetemcomitans, a periodontal pathogen, were targeted with the multifunctional dodecamer. Streptavidin was used to couple biotinylated dodecamer to a biotinylated anti-A. actinomycetemcomitans antibody. This modular targeting approach enabled us to increase the loading of photosensitizer onto the cells by a cycle of amplification. Scanning laser confocal microscopy was used to characterize transport of fluorescently tagged dodecamer into the microcolonies and targeting of the cells with biotin-labeled, fluorescently tagged dodecamer. Light-induced activity of the targeted photosensitizer reduced the viability of A. actinomycetemcomitans biofilm, as indicated by membrane permeability to propidium iodide. The functionalized multimeric protein promises to be a useful tool for controlling periodontal biofilm consortia and offers a modular design whereby moieties that target different species can be readily combined with the functionalized protein construct.

• A click chemistry based coordination polymer inside small heat shock protein.

  Authors: Janice Lucon, Md Joynal Abedin, Masaki Uchida, Lars Liepold, Craig C Jolley, Mark Young, Trevor Douglas

  Chemical communications (Cambridge, England). 01/2010; 46(2):264-6.

  A branched iron-phenanthroline based coordination polymer has been constructed in a water based system using a click chemistry approach to link monomeric coordination complexes together within aA branched iron-phenanthroline based coordination polymer has been constructed in a water based system using a click chemistry approach to link monomeric coordination complexes together within a protein cage nanoarchitecture, which acts both as a template and a sized constrained reaction environment.

• Metagenomes from high-temperature chemotrophic systems reveal geochemical controls on microbial community structure and function.

  Authors: William P Inskeep, Douglas B Rusch, Zackary J Jay, Markus J Herrgard, Mark A Kozubal, Toby H Richardson, Richard E Macur, Natsuko Hamamura, Ryan deM Jennings, Bruce W Fouke [......] Frank Roberto, Mark Young, Ariel Schwartz, Eric S Boyd, Jonathan H Badger, Eric J Mathur, Alice C Ortmann, Mary Bateson, Gill Geesey, Marvin Frazier

  PloS one. 01/2010; 5(3):e9773.

  The Yellowstone caldera contains the most numerous and diverse geothermal systems on Earth, yielding an extensive array of unique high-temperature environments that host a variety of deeply-rootedThe Yellowstone caldera contains the most numerous and diverse geothermal systems on Earth, yielding an extensive array of unique high-temperature environments that host a variety of deeply-rooted and understudied Archaea, Bacteria and Eukarya. The combination of extreme temperature and chemical conditions encountered in geothermal environments often results in considerably less microbial diversity than other terrestrial habitats and offers a tremendous opportunity for studying the structure and function of indigenous microbial communities and for establishing linkages between putative metabolisms and element cycling. Metagenome sequence (14-15,000 Sanger reads per site) was obtained for five high-temperature (>65 degrees C) chemotrophic microbial communities sampled from geothermal springs (or pools) in Yellowstone National Park (YNP) that exhibit a wide range in geochemistry including pH, dissolved sulfide, dissolved oxygen and ferrous iron. Metagenome data revealed significant differences in the predominant phyla associated with each of these geochemical environments. Novel members of the Sulfolobales are dominant in low pH environments, while other Crenarchaeota including distantly-related Thermoproteales and Desulfurococcales populations dominate in suboxic sulfidic sediments. Several novel archaeal groups are well represented in an acidic (pH 3) Fe-oxyhydroxide mat, where a higher O2 influx is accompanied with an increase in archaeal diversity. The presence or absence of genes and pathways important in S oxidation-reduction, H2-oxidation, and aerobic respiration (terminal oxidation) provide insight regarding the metabolic strategies of indigenous organisms present in geothermal systems. Multiple-pathway and protein-specific functional analysis of metagenome sequence data corroborated results from phylogenetic analyses and clearly demonstrate major differences in metabolic potential across sites. The distribution of functional genes involved in electron transport is consistent with the hypothesis that geochemical parameters (e.g., pH, sulfide, Fe, O2) control microbial community structure and function in YNP geothermal springs.

• Photochemical Mineralization of Europium, Titanium, and Iron Oxyhydroxide Nanoparticles in the Ferritin Protein Cage.

  Authors: Michael T Klem, Jesse Mosolf, Mark Young, Trevor Douglas

  Inorganic chemistry. 08/2009;

• A Streptavidin-Protein Cage Janus Particle for Polarized Targeting and Modular Functionalization.

  Authors: Peter A Suci, Sebyung Kang, Mark Young, Trevor Douglas

  Journal of the American Chemical Society. 07/2009;

  The incorporation of Janus particles into the repertoire of nanoscale building blocks adds a new level of control to supramolecular assembly. Here we demonstrate the potential for using toposelectiveThe incorporation of Janus particles into the repertoire of nanoscale building blocks adds a new level of control to supramolecular assembly. Here we demonstrate the potential for using toposelective modification to assemble new types of targeting nanoplatforms by docking the universal coupling protein, streptavidin (StAv), onto a restricted region of the surface of a small protein cage. The resulting StAv-functionalized Janus particles have the potential to be used to control the orientation of the nanoplatforms targeted to a cell surface. In addition, the StAv-biotin couple provides an ideal molecular adaptor for extending asymmetric (polarized) supramolecular assembly. To demonstrate this potential application, StAv-functionalized nanoplatforms were coupled to a biotinylated monoclonal antibody and used to target a microbial pathogen.

• Janus-like Protein Cages. Spatially Controlled Dual-Functional Surface Modifications of Protein Cages.

  Authors: Sebyung Kang, Peter A Suci, Chris C Broomell, Kenji Iwahori, Mime Kobayashi, Ichiro Yamashita, Mark Young, Trevor Douglas

  Nano letters. 06/2009;

  Protein cages have been used both as size-constrained reaction vessels for nanomaterials synthesis and as nanoscale building blocks for higher order nanostructures. We generated Janus-like proteinProtein cages have been used both as size-constrained reaction vessels for nanomaterials synthesis and as nanoscale building blocks for higher order nanostructures. We generated Janus-like protein cages, which are dual functionalized with a fluorescent and an affinity label, and demonstrated control over both the stoichiometry and spatial distribution of the functional groups. The capability to toposelectively functionalize protein cages has allowed us to manipulate hierarchical assembly using the layer-by-layer assembly process. Janus-like protein cages expand the toolkit of nanoplatforms that can be used for directed assembly of nanostructured materials.

• From Metal Binding to Nanoparticle Formation: Monitoring Biomimetic Iron Oxide Synthesis within Protein Cages using Mass Spectrometry.

  Authors: Sebyung Kang, Craig C Jolley, Lars O Liepold, Mark Young, Trevor Douglas

  Angewandte Chemie (International ed. in English). 06/2009;

• Synthesis of a cross-linked branched polymer network in the interior of a protein cage.

  Authors: Md Joynal Abedin, Lars Liepold, Peter Suci, Mark Young, Trevor Douglas

  Journal of the American Chemical Society. 05/2009; 131(12):4346-54.

  A goal of biomimetic chemistry is to use the hierarchical architecture inherent in biological systems to guide the synthesis of functional three-dimensional structures. Viruses and other highlyA goal of biomimetic chemistry is to use the hierarchical architecture inherent in biological systems to guide the synthesis of functional three-dimensional structures. Viruses and other highly symmetrical protein cage architectures provide defined scaffolds to initiate hierarchical structure assembly. Here we demonstrate that a cross-linked branched polymer can be initiated and synthesized within the interior cavity of a protein cage architecture. Creating this polymer network allows for the spatial control of pendant reactive sites and dramatically increases the stability of the cage architecture. This material was generated by the sequential coupling of multifunctional monomers using click chemistry to create a branched cross-linked polymer network. Analysis of polymer growth by mass spectrometry demonstrated that the polymer was initiated at the interior surface of the cage at genetically introduced cysteine reactive sites. The polymer grew as expected to generation 2.5 where it was limited by the size constraints of the cavity. The polymer network was fully cross-linked across protein subunits that make up the cage and extended the thermal stability for the cage to at least 120 degrees C. The introduced reactive centers were shown to be active and their number density increased with increasing generation. This synthetic approach provides a new avenue for creating defined polymer networks, spatially constrained by a biological template.

• Genetics, biochemistry and structure of the archaeal virus STIV.

  Authors: Jennifer Fulton, Brian Bothner, Martin Lawrence, John E Johnson, Trevor Douglas, Mark Young

  Biochemical Society transactions. 03/2009; 37(Pt 1):114-7.

  STIV (Sulfolobus turreted icosahedral virus) has been the subject of detailed structural, genetic, transcriptomic, proteomic and biochemical studies. STIV arguably has been investigated in moreSTIV (Sulfolobus turreted icosahedral virus) has been the subject of detailed structural, genetic, transcriptomic, proteomic and biochemical studies. STIV arguably has been investigated in more detail than any other archaeal virus. As a result, we know more about STIV than other viruses infecting members of the Archaea domain. Like most viruses isolated from crenarchaeal hosts, STIV has little in common with viruses that infect eukaryotic and bacterial hosts and should be considered the founding member of a new virus family. However, despite this lack of obvious homology with other viruses, STIV has components of gene content, replication strategy and particle structure reminiscent of viruses of the Eukarya and Bacteria domains, suggesting an evolutionary relationship between viruses from all domains of life. The present mini-review describes the current knowledge of this virus and insights it has given us into viral and cellular evolution, as well as newly developed tools for the further study of STIV-host interactions.

• Controlled assembly of bifunctional chimeric protein cages and composition analysis using noncovalent mass spectrometry.

  Authors: Sebyung Kang, Luke M Oltrogge, Chris C Broomell, Lars O Liepold, Peter E Prevelige, Mark Young, Trevor Douglas

  Journal of the American Chemical Society. 01/2009; 130(49):16527-9.

• 7 T MRI of macrophages in mouse carotid atherosclerosis using novel nanoparticle platforms

  Authors: Hisanori Kosuge, Masahiro Terashima, Masaki Uchida, Sarah Sherlock, Philip Tsao, Mark Young, Trevor Douglas, Hongjie Dai, Michael McConnell

  Journal of Cardiovascular Magnetic Resonance. 01/2009;

• Inducible Bronchus-associated lymphoid tissue elicited by a protein cage nanoparticle enhances protection in mice against diverse respiratory viruses.

  Authors: James A Wiley, Laura E Richert, Steve D Swain, Ann Harmsen, Dale L Barnard, Troy D Randall, Mark Jutila, Trevor Douglas, Chris Broomell, Mark Young, Allen Harmsen

  PloS one. 01/2009; 4(9):e7142.

  BACKGROUND: Destruction of the architectural and subsequently the functional integrity of the lung following pulmonary viral infections is attributable to both the extent of pathogen replication andBACKGROUND: Destruction of the architectural and subsequently the functional integrity of the lung following pulmonary viral infections is attributable to both the extent of pathogen replication and to the host-generated inflammation associated with the recruitment of immune responses. The presence of antigenically disparate pulmonary viruses and the emergence of novel viruses assures the recurrence of lung damage with infection and resolution of each primary viral infection. Thus, there is a need to develop safe broad spectrum immunoprophylactic strategies capable of enhancing protective immune responses in the lung but which limits immune-mediated lung damage. The immunoprophylactic strategy described here utilizes a protein cage nanoparticle (PCN) to significantly accelerate clearance of diverse respiratory viruses after primary infection and also results in a host immune response that causes less lung damage. METHODOLOGY/PRINCIPAL FINDINGS: Mice pre-treated with PCN, independent of any specific viral antigens, were protected against both sub-lethal and lethal doses of two different influenza viruses, a mouse-adapted SARS-coronavirus, or mouse pneumovirus. Treatment with PCN significantly increased survival and was marked by enhanced viral clearance, accelerated induction of viral-specific antibody production, and significant decreases in morbidity and lung damage. The enhanced protection appears to be dependent upon the prior development of inducible bronchus-associated lymphoid tissue (iBALT) in the lung in response to the PCN treatment and to be mediated through CD4+ T cell and B cell dependent mechanisms. CONCLUSIONS/SIGNIFICANCE: The immunoprophylactic strategy described utilizes an infection-independent induction of naturally occurring iBALT prior to infection by a pulmonary viral pathogen. This strategy non-specifically enhances primary immunity to respiratory viruses and is not restricted by the antigen specificities inherent in typical vaccination strategies. PCN treatment is asymptomatic in its application and importantly, ameliorates the damaging inflammation normally associated with the recruitment of immune responses into the lung.

• Controlled Assembly of Bifunctional Chimeric Protein Cages and Composition Analysis Using Noncovalent Mass Spectrometry.

  Authors: Sebyung Kang, Luke Oltrogge, Chris Broomell, Lars Liepold, Peter Prevelige, Mark Young, Trevor Douglas

  Journal of the American Chemical Society. 12/2008;

• Monitoring Biomimetic Platinum Nanocluster Formation Using Mass Spectrometry and Cluster-Dependent H(2) Production.

  Authors: Sebyung Kang, Janice Lucon, Zachary B Varpness, Lars Liepold, Masaki Uchida, Debbie Willits, Mark Young, Trevor Douglas

  Angewandte Chemie (International ed. in English). 10/2008;

• Plant Viruses as Biotemplates for Materials and Their Use in Nanotechnology.

  Authors: Mark Young, Debbie Willits, Masaki Ucida, Trevor Douglas

  Annual review of phytopathology. 06/2008;

  In recent years, plant virus capsids, the protein shells that form the surface of a typical plant virus particle, have emerged as useful biotemplates for material synthesis. All virus capsids areIn recent years, plant virus capsids, the protein shells that form the surface of a typical plant virus particle, have emerged as useful biotemplates for material synthesis. All virus capsids are assembled from virus-coded protein subunits. Many plant viruses assemble capsids with precise 3D structures providing nanoscale architectures that are highly homogeneous and can be produced in large quantities. Capsids are amenable to both genetic and chemical modifications allowing new functions to be incorporated into their structure by design. The three capsid surfaces, the interior surface, the exterior surface, or the interface between coat protein subunits, can be independently functionalized to produce multifunctional biotemplates. In this review, we examine the recent advances in using plant virus capsids as biotemplates for nanomaterials and their potential for applications in nanotechnology, especially medicine. Expected final online publication date for the Annual Review of Phytopathology Volume 46 is August 04, 2008. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.

• 2089 Detecting inflammation in atherosclerosis using protein cage nanoparticles as cellular imaging agents

  Authors: Masahiro Terashima, Masaki Uchida, Hisanori Kosuge, Shay Keren, Philip Tsao, Mark Young, Trevor Douglas, Michael McConnell

  Journal of Cardiovascular Magnetic Resonance. 01/2008;

• Viral capsids as MRI contrast agents.

  Authors: Lars Liepold, Stasia Anderson, Deborah Willits, Luke Oltrogge, Joseph A Frank, Trevor Douglas, Mark Young

  Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. 12/2007; 58(5):871-9.

  Viral capsids have the potential for combined cell/tissue targeting, drug delivery, and imaging. Described here is the development of a viral capsid as an efficient and potentially relevant MRIViral capsids have the potential for combined cell/tissue targeting, drug delivery, and imaging. Described here is the development of a viral capsid as an efficient and potentially relevant MRI contrast agent. Two approaches are outlined to fuse high affinity Gd(3+) chelating moieties to the surface of the cowpea chlorotic mottle virus (CCMV) capsid. In the first approach, a metal binding peptide has been genetically engineered into the subunit of CCMV. In a second approach gadolinium-tetraazacyclododecane tetraacetic acid (GdDOTA) was attached to CCMV by reactions with endogenous lysine residues on the surface of the viral capsid. T(1) and T(2) ionic relaxivity rates for the genetic fusion particle were R1 = 210 and R2 = 402 mM(-1)s(-1) (R2 at 56 MHz) and for CCMV functionalized with GdDOTA were R1 = 46 and R2 = 142 mM(-1)s(-1) at 61 MHz. The relaxivities per intact capsid for the genetic fusion were R1 = 36,120 and R2 = 69,144 mM(-1)s(-1) (R2 at 56 MHz) and for the GdDOTA CCMV construct were R1 = 2,806 and R2 = 8,662 mM(-1)s(-1) at 61 MHz. The combination of high relaxivity, stable Gd(3+) binding, and large Gd(3+) payloads indicates the potential of viral capsids as high-performance contrast agents.