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Radamés J.B. Cordero, PhD

  • Research Associate

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Education

PhD, Albert Einstein College of Medicine, 2012
MS, Albert Einstein School of Medicine, 2008
BS, University of Puerto Rico - Arecibo, 2005

Overview

My research work centers on the application of physical-chemical methods to study basic fungal biology. These studies comprised primary and collaborative research projects between national and international microbiologists, resulting in >40 peer-reviewed publications and >1300 citations since 2009. For my doctoral thesis work, I proposed the last-standing structural model of the Cryptococcus neoformans capsule, described its dynamic nature, and identified a new mechanism of capsular antibody function. Following my Ph.D. dissertation in 2012, I received the Young Talent Attraction Award to continue my research at the Federal University of Rio de Janeiro. During my two years in Brazil, I served in various faculty roles that validated my academic vocation, described fungal virulence synergism in a murine model of co-infection, and estimated the Average Publishable Unit in the life sciences. In 2015, I was invited to re-joined and re-locate the Casadevall laboratory at Johns Hopkins Bloomberg School of Public Health, where I currently serve as a Junior Faculty member of the Harry Feinstone Molecular Microbiology and Immunology Department. I am actively developing novel research programs in thermal microbiology and fungal melanins. I am also pursuing the commercialization of melanin-based biomaterials for long-term manned space journeys. Through my work, I seek to expand innovation via co-creation and curiosity-driven research that is of high-impact to society while promoting science communication and underrepresented populations in all fields of science.

Honors and Awards

2018 Seed Grant Technology Accelerator, JHU Bloomberg, Baltimore, MD

2017 Center for AIDS Research Award for Faculty Development, JHU, Baltimore, MD

2016 Biomedical Scholar Association Milestone for Academic Excellence, JHU, Baltimore, MD

2012-14 Young Talent Attraction Award, Science without Borders, CnPq/CAPES, Brasil

2008 Honors in Master of Science Degree (Class 2012), Einstein, USA

2007-09 T32 Molecular and Cellular Biology and Genetics Training Grant Award, NIH, USA

2005 Intramural Research Opportunity Program Award, NIAID, NIH, USA

2005 UPR President Award for Highest GPA in Microbiology Dept., 2005 Graduation, Arecibo, PR

2005 Graduate Minority Research Conference Travel Award, UC Irvine, USA

2004 Life Sciences Excellent Student Award, University of Puerto Rico

2004 Summer Research Associate Award, Purdue Cancer Center, NCI CURE Program, NIH

2004 Society of Toxicology Annual Meeting Travel Award, MD, USA

  • fungal melanin
  • polysaccharide capsule
  • microbial pathogenesis
  • Cryptococcus
  • radioprotection
  • energy budgets
  • thermal biology
  • infrared imaging
  • color-mediated thermoregulation
  • thermography
  • infrared camera
  • energy transduction
  • heat
  • temperature
  • solar
  • radiation shielding
  • energy storage
  • photovoltaics
  • scholarly communication practices

Most recent publications about melanin:

  • Impact of Yeast Pigmentation on Heat Capture and Latitudinal Distribution. Cordero RJB, Robert V, Cardinali G, Arinze ES, Thon SM, Casadevall A. Curr Biol. 2018 Aug 20;28(16):2657-2664. Pigmentation is a fundamental characteristic of living organisms that is used to absorb radiation energy and to regulate temperature. Since darker pigments absorb more radiation than lighter ones, they stream more heat, which can provide an adaptive advantage at higher latitudes and a disadvantage near the Tropics, because of the risk of overheating. This intuitive process of color-mediated thermoregulation, also known as the theory of thermal melanism (TTM), has been only tested in ectothermic animal models. Here, we report an association between yeast pigmentation and their latitude of isolation, with dark-pigmented isolates being more frequent away from the Tropics. To measure the impact of microbial pigmentation in energy capture from radiation, we generated 20 pigmented variants of Cryptococcus neoformans and Candida spp. Infrared thermography revealed that dark-pigmented yeasts heated up faster and reached higher temperatures (up to 2-fold) than lighter ones following irradiation. Melanin-pigmented C. neoformans exhibited a growth advantage relative to non-melanized yeasts when incubated under the light at 4°C but increased thermal susceptibility at 25°C ambient temperatures. Our results extend the TTM to microbiology and suggest pigmentation as an ancient adaptation mechanism for gaining thermal energy from radiation. The contribution of microbial pigmentation in heat absorption is relevant to microbial ecology and for estimating global temperatures. The color variations available in yeasts provide new opportunities in chromatology to quantify radiative heat transfer and validate biophysical models of heat flow that are not possible with plants or animals.
  • Cell-wall dyes interfere with Cryptococcus neoformans melanin deposition Perez-Dulzaides R, Camacho E, Cordero RJB, Casadevall A. Microbiology. 2018 Aug;164(8):1012-1022. Melanization is an intrinsic characteristic of many fungal species, but details of this process are poorly understood because melanins are notoriously difficult pigments to study. While studying the binding of cell-wall dyes, Eosin Y or Uvitex, to melanized and non-melanized Cryptococcus neoformans cells we noted that melanization leads to reduced fluorescence intensity, suggesting that melanin interfered with dye binding to the cell wall. The growth of C. neoformans in melanizing conditions with either of the cell-wall dyes resulted in an increase in supernatant-associated melanin, consistent with blockage of melanin attachment to the cell wall. This effect provided the opportunity to characterize melanin released into culture supernatants. Released melanin particles appeared mostly as networked structures having dimensions consistent with previously described extracellular vesicles. Hence, dye binding to the cell wall created conditions that resembled the 'leaky melanin' phenotype described for certain cell-wall mutants. In agreement with earlier studies on fungal melanins biosynthesis, our observations are supportive of a model whereby C. neoformans melanization proceeds by the attachment of melanin nanoparticles to the cell wall through chitin, chitosan, and various glucans.
  • Melanin for space travel radioprotection. Cordero RJB. Environ Microbiol. 2017 Jul;19(7):2529-2532. Melanins are special biomolecules capable of shielding from ionizing radiation, a property that could be exploited for interplanetary manned space travel.
  • Melanin, Radiation, and Energy Transduction in Fungi Casadevall A, Cordero RJB, Bryan R, Nosanchuk J, Dadachova E. Microbiol Spectr. 2017 Mar;5(2). Melanin pigments are found in many diverse fungal species, where they serve a variety of functions that promote fitness and cell survival. Melanotic fungi inhabit some of the most extreme habitats on earth such as the damaged nuclear reactor at Chernobyl and the highlands of Antarctica, both of which are high-radiation environments. Melanotic fungi migrate toward radioactive sources, which appear to enhance their growth. This phenomenon, combined with the known capacities of melanin to absorb a broad spectrum of electromagnetic radiation and transduce this radiation into other forms of energy, raises the possibility that melanin also functions in harvesting such energy for biological usage. The ability of melanotic fungi to harness electromagnetic radiation for physiological processes has enormous implications for biological energy flows in the biosphere and for exobiology, since it provides new mechanisms for survival in extraterrestrial conditions. Whereas some features of the way melanin-related energy transduction works can be discerned by linking various observations and circumstantial data, the mechanistic details remain to be discovered.
  • Functions of fungal melanin beyond virulence Cordero RJB and Casadevall A. Fungal Biology Reviews. Volume 31, Issue 2, March 2017, Pages 99-112. Melanins are ancient biological pigments found in all kingdoms of life. In fungi, their role in microbial pathogenesis is well established; however, these complex biomolecules also confer upon fungal microorganisms the faculty to tolerate extreme environments such as the Earth's poles, the International Space Station and places contaminated by toxic metals and ionizing radiation. A remarkable property of melanin is its capacity to interact with a wide range of electromagnetic radiation frequencies, functioning as a protecting and energy harvesting pigment. Other roles of fungal melanin include scavenging of free radical, thermo-tolerance, metal ion sequestration, cell development, and mechanical-chemical cellular strength. In this review, we explore the various functions ascribed to this biological pigment in fungi and its remarkable physicochemical properties.
  • Structure and Function of the Cryptococcal Capsule
  • Structure and Functions of Fungal Melanins
  • Thermal biology of fungi