Malik S.S.,University of Maryland Baltimore County |
Patterson D.N.,University of Maryland Baltimore County |
Ncube Z.,Coppin State University |
Toth E.A.,University of Maryland Baltimore County
Proteins: Structure, Function and Bioinformatics | Year: 2014
Quinolinic acid (QA), a biologically potent but neurodestructive metabolite is catabolized by quinolinic acid phosphoribosyltransferase (QPRT) in the first step of the de novo NAD+ biosynthesis pathway. This puts QPRT at the junction of two different pathways, that is, de novo NAD+ biosynthesis and the kynurenine pathway of tryptophan degradation. Thus, QPRT is an important enzyme in terms of its biological impact and its potential as a therapeutic target. Here, we report the crystal structure of human QPRT bound to its inhibitor phthalic acid (PHT) and kinetic analysis of PHT inhibition of human QPRT. This structure, determined at 2.55 Å resolution, shows an elaborate hydrogen bonding network that helps in recognition of PHT and consequently its substrate QA. In addition to this hydrogen bonding network, we observe extensive van der Waals contacts with the PHT ring that might be important for correctly orientating the substrate QA during catalysis. Moreover, our crystal form allows us to observe an intact hexamer in both the apo- and PHT-bound forms in the same crystal system, which provides a direct comparison of unique subunit interfaces formed in hexameric human QPRT. We call these interfaces "nondimeric interfaces" to distinguish them from the typical dimeric interfaces observed in all QPRTs. We observe significant changes in the nondimeric interfaces in the QPRT hexamer upon binding PHT. Thus, the new structural and functional features of this enzyme we describe here will aid in understanding the function of hexameric QPRTs, which includes all eukaryotic and select prokaryotic QPRTs. Proteins 2014; 82:405-414. © 2013 Wiley Periodicals, Inc.
Attota R.K.,U.S. National Institute of Standards and Technology |
Kang H.,Coppin State University
Optics Express | Year: 2016
It is important to economically and non-destructively analyze three-dimensional (3-D) shapes of nanometer to micrometer scale objects with sub-nanometer measurement resolution for emerging high-volume nanomanufacturing, especially for process control. High-throughput through-focus scanning optical microscopy (TSOM) demonstrates promise for such applications. TSOM uses a conventional optical microscope for 3-D shape metrology by making use of the complete set of through-focus, four-dimensional optical data. However, a systematic study showing the effect of various parameters on the TSOM method is lacking. Here we present the optimization of the basic parameters such as illumination numerical aperture (NA), collection NA, focus step height, digital camera pixel size, illumination polarization, and illumination wavelength to achieve peak performance of the TSOM method. © 2016 OSA.
Varma S.D.,University of Maryland Baltimore County |
Kovtun S.,University of Maryland Baltimore County |
Hegde K.R.,Coppin State University
Eye and Contact Lens | Year: 2011
Purpose: Cataract is a significant cause of visual disability with relatively high incidence. It has been proposed that such high incidence is related to oxidative stress induced by continued intraocular penetration of light and consequent photochemical generation of reactive oxygen species, such as superoxide and singlet oxygen and their derivatization to other oxidants, such as hydrogen peroxide and hydroxyl radical. The latter two can also interact to generate singlet oxygen by Haber-Weiss reaction. It has been proposed that in addition to the endogenous enzymatic antioxidant enzymes, the process can be inhibited by many nutritional and metabolic oxyradical scavengers, such as ascorbate, vitamin E, pyruvate, and xanthine alkaloids, such as caffeine. Methods: Initial verification of the hypothesis has been done primarily by rat and mouse lens organ culture studies under ambient as well as ultraviolet (UV) light irradiation and determining the effect of such irradiation on its physiology in terms of its efficiency of active membrane transport activity and the levels of certain metabolites such as glutathione and adenosine triphosphate as well as in terms of apoptotic cell death. In vivo studies on the possible prevention of oxidative stress and cataract formation have been conducted by administering pyruvate and caffeine orally in drinking water and by their topical application using diabetic and galactosemic animal models. Results: Photosensitized damage to lens caused by exposure to visible light and UVA has been found to be significantly prevented by ascorbate and pyruvate. Caffeine has been found be effective against UVA and UVB. Oral or topical application of pyruvate has been found to inhibit the formation of cataracts induced by diabetes and galactosemia. Caffeine has also been found to inhibit cataract induced by sodium selenite and high levels of galactose. Studies with diabetes are in progress. Conclusions: Various in vitro and in vivo studies summarized in this review strongly support the hypothesis that light penetration into the eye is a significant contributory factor in the genesis of cataracts. The major effect is through photochemical generation of reactive oxygen species and consequent oxidative stress to the tissue. The results demonstrate that this can be averted by the use of various antioxidants administered preferably by topical route. That they will be so effective is strongly suggested by the effectiveness of pyruvate and caffeine administered topically to diabetic and galactosemic animals. © 2011 Lippincott Williams & Wilkins.
Reddy S.G.,Coppin State University |
York V.K.,Kansas State University |
Brannon L.A.,Kansas State University
International Journal of Tourism Research | Year: 2010
Medical tourism is the act of travelling abroad for health care. The theory of planned behaviour was used to investigate the medical tourism beliefs of 336 undergraduate students in a basic psychology course at a large midwestern American university. Students did not have positive intentions for mere willingness to seek more information about travelling to a developing country to receive medical treatment. An educational intervention is necessary to help promote travel for medical treatment. The intervention may include educating people on the availability of quality health care, highly trained competent doctors and the ability to vacation and see another country. © 2010 John Wiley & Sons, Ltd.
Description: Coppin State University’s Science and Technology Center is a building that addresses and fulfills the aspirations of the university, the students and the surrounding neighborhood. Coppin State’s desire to prepare its students for careers in science, technology, engineering and mathematics (STEM) required a new, state-of-the-art facility that would deliver increased opportunities for its high-minority student population to excel in STEM learning. The design of the new building intentionally opens up the campus to the city as a place for optimism, transparency and hope. The building engages the neighborhood with a zone of teaching gardens, shallow site walls and landscape, all designed to allow for transparent visual connections and a comfortable and safe setting for the students. The adjacent green quadrangle, to be used for the commencement celebrations, is open to the public year-round and acts as a warm and welcoming gesture to share in the university’s success and the community’s pride. A new set of broad campus steps link the lower level green quadrangle to North Avenue, a main east/west link to downtown Baltimore. These steps incorporate marble from the stoops of houses that were previously on the site to make a series of low stone benches at the edge of North Avenue. The steps also align with a focal point of the building, a cubic glass building volume which houses the faculty offices. The cube appears to float over the main building entrance and glow at night, revealing the activity inside. The internal organization of the building was determined through numerous discussions with the faculty as well as a detailed program analysis. The design encourages faculty and students from different science departments to collaborate on projects that cross traditional departmental boundaries. All labs and classrooms are designed for project teams of two to eight people to work together as part of the STEM learning experience. General classrooms and computer labs for campus-wide use are included on the lower level. The entry level is active and vibrant, with exhibit space, a small café and a 100-seat lecture hall.