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  8. Angel Paredes
  1. Science & Research (NCTR)

Angel Paredes Ph.D.

Research Biologist — Office of Scientific Coordination

Dr. Angel Paredes
Angel Paredes, Ph.D.

(870) 543-7391

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About  |  Publications 


Dr. Angel Paredes started his training in electron microscopy in 1983 in the Department of Microbiology at the University of Texas at Austin as a graduate student. Later, during his doctoral studies, he conducted electron cryomicroscopy (cryoEM) to determine the structure of the Sindbis virus, a prototype alphavirus. For the next 18 years, he continued his work in electron cryomicroscopy, first at Baylor College of Medicine and later at the University of Texas Health Science Center in Houston (UTHSC). During his tenure at Baylor, he was called upon to help manage the facility’s high-end electron microscopes where he was one of three managers that was able to maintain the microscope and train students. He was later hired by UTHSC to manage their new electron cryomicroscopy laboratory, first as manager and later as a tenured track assistant professor. For over 15 years, he has played a major role in managing electron microscopes and conducting research with these instruments. He presently oversees the electron microscopy laboratory at NCTR.

Research Interests

Dr. Paredes is interested in conducting FDA-relevant research that explores the structural impact of drug treatment and drug-host interactions. In any biological or biochemical process that occurs in the body, whether natural or induced by a manmade pharmacological reaction, there is always a structural impact. This is a consequence of the structure-function relationship that drives all biology. Whether that structural effect is beneficial or deleterious is the basis for the therapeutic effect any drug is designed to elicit. Specifically, Dr. Paredes is interested in identifying the global structural changes that accompany the treatment of humans and veterinary animals to FDA-regulated products including food, drugs, makeup, and nanotechnology. He can use his expertise in electron microscopy to investigate these changes in tissues and organs at the sub-microscopic level. He would like to continue to develop one technology in particular — Serial Block Face Scanning Electron Microscopy (SBFSEM). This instrument, which he presently uses to conduct research, allows his laboratory to slice through tissues from treated animals, gathering images after each slice. The result is digital reconstructions of affected tissues that can be analyzed by very powerful image analysis software. Using this technology he plans to highlight the toxicological effects of FDA-regulated drugs. The data from his research will help FDA ensure product safety in the future.

Professional Societies/National and International Groups

American Society for Testing and Materials
2016 – Present


Select Publications

Publication titles are linked to text abstracts on PubMed.

Differential Effects of Silver Nanoparticles and Silver Ions on Tissue Distribution and Toxicity in yhe Sprague Dawley Rat Following Daily Oral Gavage Administration for 13-Weeks.
Boudreau M, Imam M, Paredes A, Bryant M, Cunningham C, Felton R, Jones M, Davis K, Olson G.
Toxicol. Sci. 2016; 1:131-60.

Microscopy: Transmission Electron Microscopy. disclaimer icon
Paredes A.  
Encyclopedia of Food Microbiology. 2013. Second Edition. Netherlands: Elsevier.

Fatty Aldehydes in Cyanobacteria are a Metabolically Flexible Precursor for Adversity of Biofuel Products. disclaimer icon
Kaiser B, Carleton M, Hickman J, Miller C, Lawson D, Budde M, Warrener P, Paredes, A, Mullapudi S, Navarro P, Cross F, Roberts J.
PLoS One. 2013. Vol. 8(3):e58307.

Espiritio Santo Virus: A New Birnavirus that Replicates in Insect Cells.
Vancini R, Paredes A, Ribeiro M, Ferreira D, Hernandez R, Brown D.
J Virol. 2012; 86(5):2390-9.

DNA Ejection by Cryo-Electron Tomography of Spore-Binding Phage. 
Fu X, Walter M, Paredes A, Morais M, Lui J.
Virology. 2011. Vol. 421(2): pp141-148.

Reconstitution of the Platelet Glycoprotein Ib-IX Complex in Phospholipid Bilayer Nanodiscs.
Yan R, Mo X, Paredes A, Dai K, Lanza F, Cruz M, Li R.
Biochemistry. 2011. Vol. 50(49):10598-606.

Plasma Restoration of Endothelial Glycocalyx in a Rodent Model of Hemorrhagic Shock. 
Kozar R, Peng Z, Holcomb J, Pati S, Park P, Ko T, Paredes A.
Anesth. Analg. 2011. Vol. 112(6):1289-1295.

Sindbis Virus as a Model for Studies of Conformational Changes in a Metastable Virus and the Role of Conformational Changes in In Vitro Antibody Neutralization.
Hernandez R, Paredes A.
Rev. Med. Virology. 2009; 19(5):257-72.

Intra- and Intermembrane Pairwise Molecular Recognition between Synthetic Hydrogen-Bonding Phospolipids.
Ma M, Paredes A, Bong D.
J. American Chem. Soc. 2008. 44: 14456-8.

Sindbis Virus Conformational Changes Induced by a Neutralizing Anti-E1 Monoclonal Antibody.
Hernandez R, Paredes A, West M, Brown D.
J. Virology. 2008. Vol. 82:5750-5760.

Structure of Halothiobacillus Neapolitanus Carboxysomes by Cryo-Electron Tomography.
Schmid M, Paredes A, Khant H, Soyer F, Aldrich H, Chiu W, Shively J.
J. Molecular Biology. 2006. Vol. 364, No. 3, pp526-35.

Structural Biology of Old World and New World Alphaviruses.
Paredes A, Weaver S, Watowich S, Chiu W.
Arch Virol Suppl. 2005. 19: 179-185.

Conformational Changes in Sindbis Virions Resulting from Exposure to Low pH and Interactions with Cells Suggest that Cell Penetration may Occur at the Cell Surface in the Absence of Membrane Fusion.
Paredes A, Ferreira D, Horton M, Saad A, Tsuruta H, Johnston R, Klimstra W, Ryman K, Hernandez R, Chiu W, Brown D.
Virology. 2004. 324(2), 373-86.

Structure of Isolated Nucleocapsids from Venezuelan Equine Encephalitis Virus and Implications for Assembly and Disassembly of Enveloped Viruses. 
Paredes A, Alwell-Warda K, Weaver S, Chiu W, Watowich S.
J. Virology. 2003. Vol. 77: 659-664.

Venezuelan Equine Encephalomyelitis Virus Structure and its Divergence from Old World Alphaviruses.
Paredes A, Alwell-Warda K, Weaver S, Chiu W, Watowich S.  
 J. Virology. 2001. Vol. 75:9532-9537.

Structural Localization of the E3 Glycoprotein in Attenuated Sindbis Virus Mutants.
Paredes A, Heidnes H, Thuman-Commike P, Prasad B, Johnston R, Chiu W.
J. Virol. 1998. 72(2):1534-41.

Three-Dimensional Structure of a Membrane-Containing Virus.
Paredes A, Brown D, Rothnagel R, Chiu W, Schoepp R, Johnston R, Prasad B.
Proc. Natl. Acad. Sci. 1993; USA 90:9095-9099.


Contact Information
Angel Paredes
(870) 543-7391
Technology & Discipline
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