Microevolution of group A streptococci in vivo: capturing regulatory networks engaged in sociomicrobiology, niche adaptation, and hypervirulenceRamy K Aziz
Research Services, Veterans Affairs Medical Center, Memphis, Tennessee, United States of America
PLoS ONE 5:e9798. 2010
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- The case for biocentric microbiology
Ramy Karam Aziz
Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, 11562 Cairo, Egypt
Gut Pathog 1:16. 2009
..Here, I argue that an exclusively biocentric microbiology is imperative for improving our understanding not only of the microbial world, but also of our own species, our guts, and the world around us...
- Rise and persistence of global M1T1 clone of Streptococcus pyogenes
Ramy K Aziz
Department of Microbiologyand Immunology, Cairo University, Cairo, Egypt
Emerg Infect Dis 14:1511-7. 2008
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- Transposases are the most abundant, most ubiquitous genes in nature
Ramy K Aziz
Computation Institute, University of Chicago, Chicago, IL 60637, USA
Nucleic Acids Res 38:4207-17. 2010
..By securing their own replication and dissemination, transposases guarantee to thrive so long as nucleic acid-based life forms exist...
- Helicobacter pylori: a poor man's gut pathogen?
Mohammed Mahdy Khalifa
Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, 11562 Cairo, Egypt
Gut Pathog 2:2. 2010
..These data are alarming in the light of the changing global climate and birth rate, which are expected to change the demography of our planet, putting more children at risk of H. pylori and its complications for years to come...
- A hundred-year-old insight into the gut microbiome!
Ramy Karam Aziz
Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, 11562 Cairo, Egypt
Gut Pathog 1:21. 2009
..Kendall, published in The Journal of Biological Chemistry in November 1909 (Some observations on the study of the intestinal bacteria J Biol Chem 1909, 6:499-507), offers a visionary insight into many of today's hot research questions...
- Pathogen microevolution in high resolution
Ramy K Aziz
Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo 11562, Egypt
Sci Transl Med 2:16ps4. 2010
..aureus strain, can provide new clues about the geographical origin and intrahospital spread of important microbial pathogens...
- An unbiased systems genetics approach to mapping genetic loci modulating susceptibility to severe streptococcal sepsis
Nourtan F Abdeltawab
Mid South Center for Biodefense and Security, The University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
PLoS Pathog 4:e1000042. 2008
..The association of GAS sepsis with multiple pathways underscores the complexity of traits modulating GAS sepsis and provides a powerful approach for analyzing interactive traits affecting outcomes of other infectious diseases...
- Post-proteomic identification of a novel phage-encoded streptodornase, Sda1, in invasive M1T1 Streptococcus pyogenes
Ramy K Aziz
Department of Molecular Sciences, University of Tennessee, Health Science Center, Memphis, TN, USA
Mol Microbiol 54:184-97. 2004
..Ongoing studies in our laboratory aim to determine the contribution of Sda1 to the virulence of this globally disseminated M1T1 strain...
- Inactivation of DltA modulates virulence factor expression in Streptococcus pyogenes
Kathleen H Cox
Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
PLoS ONE 4:e5366. 2009
..In this study, we have further investigated the effects that mutating dltA has on virulence factor expression in Streptococcus pyogenes...
- Dissection of the molecular basis for hypervirulence of an in vivo-selected phenotype of the widely disseminated M1T1 strain of group A Streptococcus bacteria
Rita G Kansal
Department of Veterans Affairs Medical Center, Research Service, University of Tennessee Health Science Center, Memphis, TN 38104, USA
J Infect Dis 201:855-65. 2010
..Correction of the covS mutation in AP bacteria reverted them back to the WT phenotype. Our data confirm that covS plays a direct role in regulating GAS virulence...
- Modulation of expression of superantigens by human transferrin and lactoferrin: a novel mechanism in host-Streptococcus interactions
Rita G Kansal
Veterans Affairs Medical Center, Research Service, and Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee 38104, USA
J Infect Dis 191:2121-9. 2005
..Thus, ferrins may play an important role in host-pathogen interactions in skin and mucosal tissues...
- Streptococcal mitogenic exotoxin, SmeZ, is the most susceptible M1T1 streptococcal superantigen to degradation by the streptococcal cysteine protease, SpeB
Mohammed M Nooh
Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
J Biol Chem 281:35281-8. 2006
..The study provides evidence for the effect of subtle structural differences between highly similar SAgs on their biological activity...
- Mosaic prophages with horizontally acquired genes account for the emergence and diversification of the globally disseminated M1T1 clone of Streptococcus pyogenes
Ramy K Aziz
Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis 38163, USA
J Bacteriol 187:3311-8. 2005
..Y, replacing it with a different module identical to that found on a related M3 phage. Taken together, the data demonstrate that mosaicism of the GAS prophages has contributed to the emergence and diversification of the M1T1 subclone...
- DNase Sda1 provides selection pressure for a switch to invasive group A streptococcal infection
Mark J Walker
School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia
Nat Med 13:981-5. 2007
..The results provide a paradigm whereby natural selection exerted by the innate immune system generates hypervirulent bacterial variants with increased risk of systemic dissemination...
- Streptococcus iniae M-like protein contributes to virulence in fish and is a target for live attenuated vaccine development
Jeffrey B Locke
Department of Pediatrics, University of California San Diego, La Jolla, California, United States of America
PLoS ONE 3:e2824. 2008
..Through pyrosequencing of the S. iniae genome we have identified two gene homologues to classical surface-anchored streptococcal virulence factors: M-like protein (simA) and C5a peptidase (scpI)...
- The National Microbial Pathogen Database Resource (NMPDR): a genomics platform based on subsystem annotation
Leslie Klis McNeil
National Center for Supercomputing Applications, Urbana, IL 61801, USA
Nucleic Acids Res 35:D347-53. 2007
..Essentiality data collated from genome-wide studies have been curated. Drug target identification and high-throughput, in silico, compound screening are in development...
- Genetic characterization and virulence role of the RALP3/LSA locus upstream of the streptolysin s operon in invasive M1T1 Group A Streptococcus
Laura A Kwinn
Department of Pediatrics, Division of Pharmacology and Drug Discovery, University of California, San Diego School of Medicine, Cellular and Molecular Medicine East, La Jolla, CA 92093 0687, USA
J Bacteriol 189:1322-9. 2007
..Isogenic M1T1 GAS mutants lacking either RALP3 or LSA were attenuated in a murine model of systemic infection, indicating that this locus plays a role in the virulence potential of the organism...
- DNase expression allows the pathogen group A Streptococcus to escape killing in neutrophil extracellular traps
John T Buchanan
Department of Pediatrics, University of California, San Diego, La Jolla, California 92093, USA
Curr Biol 16:396-400. 2006
..The results demonstrate a significant role for NETs in neutrophil-mediated innate immunity, and at the same time identify a novel therapeutic target against invasive GAS infection...
- Invasive M1T1 group A Streptococcus undergoes a phase-shift in vivo to prevent proteolytic degradation of multiple virulence factors by SpeB
Ramy K Aziz
Department of Microbiology, University of Tennessee-Health Sciences Center (UTHSC) Memphis, TN, USA
Mol Microbiol 51:123-34. 2004
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