Source: http://connect.rtrn.net/profileswebroot/ProfileDetails.aspx?From=SE&Person=2151&PersonSource=University%20of%20Texas%20at%20San%20Antonio
Timestamp: 2019-04-26 07:45:10+00:00

Document:
Dr. Klose’s lab is interested in bacterial pathogenesis -- how bacteria cause disease. Dr. Klose has worked most extensively with Vibrio cholerae, the bacterium that causes cholera, and is also researching Francisella tularensis, the bacterium that causes tularemia, or rabbit fever.
Cholera is found only where there are widespread problems with sanitation, so improving water and food supplies would eliminate the disease. Since that is unlikely to occur, a safe, cheap, effective vaccine is needed that would protect people. To design such a vaccine, the lab is addressing questions such as: How does V. cholerae know that it is in a human body and that is the place to express genes necessary for its survival and disease potential? What are the genetic factors responsible for V. cholerae to cause disease? How does this organism persist in aquatic environments, which lead to human infection?
Very little is known about F. tularensis or about tularemia. It is a highly virulent organism and can easily be aerosolized, so it is classified by the Centers for Disease Control (CDC) as a Category A select agent with the highest potential to be used as a biological weapon. The lab is working to identify genetic factors responsible for F. tularensis to cause disease and to develop suitable vaccine candidates to protect against tularemia infection.
Francisella tularensis (Ft), Yersinia pestis (Yp), and Bacillus anthracis (Ba) are considered Category A bioweapons due to ease of transmission, low infectious dose and high mortality associated with pneumonic forms of disease, and the fact that all have been intensively studied and developed in bioweapons programs in several countries. There are currently no vaccines against tularemia or plague approved for general human use, rendering mankind at significant risk from the illicit use of Ft and Yp. Our prior studies have shown that a Ft subsp. novicida (Fn) FPI mutant (Fn-iglD) can protect against a pulmonary challenge of Ft subsp. tularensis (Ftt), in both rat and non-human primate (NHP) models of tularemia. This is an extremely promising result, because Fn is naturally avirulent toward humans, and thus a safer basis for a human vaccine. Antibodies against the Yp F1 capsular and LcrV virulence antigens fused into a single polypeptide (F1V) have been shown to be protective against Yp pulmonary challenge in several animal models, including NHP. Moreover, antibodies against the Ba protective antigen (PA) protect against Ba pulmonary challenge. The studies outlined here are designed to optimize the Fn-iglD vaccine platform to provide protection against Yp and Ba by expression of F1V and PA. The Fn-iglD vaccine strain will be engineered to present F1V on its surface and to secrete PA. The efficacy of this vaccine to protect against pulmonary challenge with Ftt and/or Yp, as well as challenge with anthrax lethal toxin (LT) will be measured in the rat model. The result of these studies will be a vaccine with broad efficacy against multiple biothreat agents. The collaborative team at UTSA and UTHSCSA has extensive experience in tularemia, plague, and anthrax vaccine development that will propel the further development of this biothreat vaccine platform. The R21 mechanism is intended to fund ?early and conceptual stages of project development?; upon completion of the experiments outlined in this proposal, this project will be poised for the submission of a well-developed RO1 proposal directed at an effective multivalent biodefense vaccine.
DESCRIPTION (provided by applicant): Chlamydia trachomatis causes ocular and genital infections in humans, which can lead to blindness and infertility. Chlamydia pneumoniae infections are a cause of pneumonia and a risk factor for chronic obstructive pulmonary disease, asthma, and atherosclerosis. Despite their immense impact on human health, relatively little is known about the genetics of Chlamydia pathogenesis, because no genetic techniques exist to create targeted mutants in these organisms. Thus there is a pressing need for the development of genetic systems to manipulate the chromosome of Chlamydia. We have created plasmids based on pCHL1, the natural plasmid found in C. trachomatis, and this will provide the basis of a gene disruption system to initiate genetic manipulation of this elusive group of bacteria. We will use this plasmid as the basis for the development of genetic manipulation techniques in Chlamydiae. We will first optimize transformation conditions to isolate both C. trachomatis and C. muridarum carrying the plasmid. We will then adapt the plasmid to deliver a Group II intron into Chlamydia, to facilitate site-specific gene inactivation. Successful transformation and genetic modification of Chlamydia species will propel the study of this important group of human pathogens forward, and allow for the development of novel therapeutics and vaccines against these bacteria.
DESCRIPTION (provided by applicant): Chlamydia trachomatis causes ocular and genital infections in humans, which can lead to blindness and infertility. Chlamydia pneumoniae infections are a cause of pneumonia and a risk factor for chronic obstructive pulmonary disease, asthma, and atherosclerosis. Despite their immense impact on human health, relatively little is known about the genetics of Chlamydia pathogenesis, because no genetic techniques exist to create targeted mutants in these organisms. Thus there is a pressing need for the development of genetic systems to manipulate the chromosome of Chlamydia. We have created plasmids based on pCHL1, the natural plasmid found in C. trachomatis, and this will provide the basis of a gene disruption system to initiate genetic manipulation of this elusive group of bacteria. We will use this plasmid as the basis for the development of genetic manipulation techniques in Chlamydiae. We will first optimize transformation conditions to isolate both C. trachomatis and C. muridarum carrying the plasmid. We will then adapt the plasmid to deliver a Group II intron into Chlamydia, to facilitate site-specific gene inactivation. Successful transformation and genetic modification of Chlamydia species will propel the study of this important group of human pathogens forward, and allow for the development of novel therapeutics and vaccines against these bacteria. PUBLIC HEALTH RELEVANCE: Chlamydia spp. cause a number of human infectious diseases, most notably sexually transmitted disease and ocular disease, which have a huge negative impact on human health that includes sterility and blindness. These studies are aimed at developing genetic techniques for Chlamydia spp, which will allow for a better understanding of disease and lead to novel cures and therapies.
Cholera is an often-fatal diarrheal disease caused by the bacterium Vibrio cholerae. This disease remains a health threat for the majority of the world, causing thousands of deaths every year. ToxT is the primary transcriptional activator of virulence genes in V. cholerae, and strains lacking toxT do not express the critical factors cholera toxin and toxin-coregulated pilus, and are unable to colonize the intestine and cause disease. ToxT transcriptional activity is regulated by certain environmental signals, and specifically by the presence of bile. Given the essential role of ToxT in cholera pathogenesis, a deeper understanding of this protein is critical for the development of new therapeutics and vaccines against this disease. Our studies will focus on characterizing the structure and function of ToxT, and determining the molecular mechanism(s) of environmental modulation of ToxT transcriptional activity. We have created a scanning alanine mutant library of ToxT in which every amino acid has been replaced with Alanine. We will utilize this library to examine the roles of individual amino acids in the function of ToxT. Our approach first involves characterizing the residues that are essential for ToxT activity, determining which amino acids are required for i). DNA binding, ii). dimerization, and iii). contact with RNA Polymerase. We will determine the structure of ToxT utilizing X-ray crystallography, and integrate the information into the functional studies to refine our understanding of ToxT transcriptional activity. We will determine the mechanism of environmental modulation of ToxT transcriptional activity by environmental signals, by i). characterizing differential transcriptional activation of ToxT-dependent promoters, ii). identifying ToxT amino acids involved in environmental modulation, iii). identifying additional V. cholerae genes involved in environmental modulation of ToxT activity, and iv). determining the effects of environmental modulation on ToxT dimerization. Finally, the relevance of the critical ToxT residues involved in function and environmental modulation will be assessed by testing the virulent properties of V. cholerae strains containing these mutant toxT alleles. Our ultimate goal is to learn how ToxT functions, in order to utilize this information to design new therapeutics and/or rationally designed live attenuated vaccines to combat cholera.
DESCRIPTION (provided by applicant): Francisella tularensis is considered a Category A bioweapon due to the ease of transmission, the low infectious dose and high mortality associated with pneumonic tularemia, and the fact that it has been intensively studied and developed in bioweapons programs in several countries. Virtually nothing is known about virulence of aerosolized forms of the most likely bioweapon, F. tularensis subsp. tularensis. The focus of this research effort is to identify all the essential and virulence genes of F. tularensis subsp. tularensis through a genomics based approach. This will dramatically increase our understanding of F. tularensis pathogenesis, and facilitate the development of subunit and live-attenuated vaccines. First, we will utilize a genomics based technique termed GAMBIT to mutagenize every gene of F. tularensis subsp. tularensis, and then recombine them back onto the chromosome. This will allow for the identification of essential genes, which are potential therapeutic targets. The viable mutant bacteria will be combined in pools and inoculated via aerosol into mice, and those mutants that cannot survive within the host will be identified by a microarray-based technique. This technique will identify all genes important for F. tularensis virulence via the aerosol route, some of which may be potential subunit vaccine candidates. Next, the attenuated F. tularensis subsp. tularensis strains will be tested for markers of virulence: ability for intramacrophage survival and growth, resistance to antimicrobial compounds, and ability to invade nonphagocytic cells. This will allow for the identification and characterization of critical virulence determinants of F. tularensis. Finally, we will characterize the virulence regulatory factors identified by microarray analysis of transcription, including the transcriptional activator MgIA, which should illuminate virulence regulons within Francisella, allowing a better understanding of the molecular mechanisms of pathogenesis. Our research plan involves a multidisciplinary approach and high levels of integration with the other projects that compose this program project. Our combined expertise will propel our knowledge of F. tularensis pathogenesis and immunity and allow for the development of novel therapeutic and preventive measures.
DESCRIPTION (provided by applicant): Francisella tularensis can cause serious illness and death in humans. F. tularensis is considered to be one of the most likely bioweapons due to ease of dissemination through aerosolization, and the high morbidity and mortality associated with inhalation tularemia. There is currently no tularemia vaccine licensed for general use, and thus human populations are at significant risk from the illicit use of F. tularensis. Very little is known about F. tularensis pathogenesis and host response, and thus fundamental research into F. tularensis biology is critical for the future development of therapeutics and vaccines against tularemia. We have assembled a group of integrated research projects focused on Francisella pathogenesis and immunity from researchers at the University of Texas San Antonio and the University of Texas Health Science Center in San Antonio. The individual projects are designed to be highly integrated with the other projects, and ultimately lead to a synergy that will propel our knowledge of this potential bioweapon such that new antimicrobial strategies can be developed. Virtually nothing is known about aerosol infections of F. tularensis subsp. tularensis (Type A), the most likely bioweapon form of tularemia, and thus this program project focuses almost exclusively on this form of tularemia. Our integrated bacteriological and immunological research approach involves four research projects and three support cores. These projects are designed to 1. identify essential and virulence factors of F. tularensis, 2. detail the immunology of inhalation tularemia in situ, 3. characterize the role of Toll-like receptors in host response, and 4. identify T cell epitopes and characterize T cell mediated responses to F. tularensis. These projects will be supported by an administrative core, a genomics core, and an immunomicroscopy core. The collaborative interactions of the investigators will ultimately lead to a dramatic increase in our understanding of pathogen-host interactions during F. tularensis subsp. tularensis aerosol infections, and facilitate the development of novel therapeutics and vaccines to combat weaponized tularemia.
DESCRIPTION (provided by applicant): Cholera is a human diarrheal disease caused by the bacterium Vibrio cholerae. This disease remains a health threat for the majority of the world, causing thousands of deaths every year. Our laboratory has shown that the alternate sigma factor, sigma54, contributes to the virulence of V. cholerae. Sigma54 regulates multiple cellular processes, including flagellar and chemotaxis gene transcription. Both motility and chemotaxis have been shown by various means to contribute to V. cholerae virulence, but the mechanism(s) linking these behaviors to virulence has been elusive. We have shown that the activity of one of the sigma54-dependent activators, FlrC, regulates enhanced intestinal colonization as well as flagellar synthesis. Flagellar synthesis, in turn, regulates the expression of a polysaccharide (VPS) necessary for biofilm formation. VPS expression is modulated by another sigma54-dependent activator, VpsR. VpsR is also necessary for virulence factor expression and intestinal colonization. Thus sigma54 appears to contribute to flagellar synthesis, chemotaxis, biofilm formation, and virulence, in part through two different (54-dependent activators, FlrC and VpsR. This proposal will focus on the contributions of these two sigma54-dependent activators to virulence and biofilm formation, as well as address the contribution of chemotaxis, a CT54-dependent phenomenon, on V. cholerae virulence. Experiments are designed to: 1. Identify the factors that regulate FlrC activity, as well as the gene(s) regulated by FlrC that contribute to intestinal colonization. 2. Characterize the role of chemotaxis in V. cholerae virulence, focusing primarily on methyl-accepting chemoreceptors (MCPs), and 3. Analyze the contribution of VpsR to VPS expression and virulence factor expression. These experiments are designed to illuminate how sigma54 controls the virulence and environmental persistence (i.e., biofilm formation) of V. cholerae through two activators, FlrC and VpsR, and through chemotaxis. The results should lead to a deeper understanding of virulence mechanisms of V. cholerae, and facilitate the discovery of novel antimicrobial therapies that can prevent cholera.
Cholera is an often-fatal diarrheal disease caused by the bacterium Vibrio cholerae. This disease remains a health threat for the majority of the world, causing thousands of deaths every year. We have recently demonstrated that ToxT, the primary transcriptional activator of virulence genes in K cholerae, is negatively regulated by certain environmental signals, and specifically by the presence of bile. Our studies will focus on dissecting the molecular mechanism(s) of environmental modulation of ToxT transcriptional activity, utilizing bile as an environmental modulatory factor. We wish to understand and exploit this negative regulation to develop novel means to prevent cholera. Essentially nothing is known about the structure/function of ToxT, so these studies also include the elucidation of the functions of the ToxT protein. Our approach first involves characterizing the domain structure of ToxT. This will be accomplished by (i). construction and characterization of chimeric ToxT proteins, and (ii). identification of ToxT amino acids important for DNA binding and transcriptional activation. Further characterization of ToxT will include the identification of all the ToxT-regulated genes of V. cholerae by microarray analysis, and the characterization of the ToxT DNA binding site(s). Once we have a more thorough understanding of ToxT, we will determine the mechanism of modulation of ToxT transcriptional activity by environmental signals, utilizing bile as the modulatory factor. These studies include: (i). determination of the effect of the porins OmpU and OmpT (which are known to be differentially permeable to bile) on bile modulation of ToxT activity, (ii). identification of additional V. cholerae genes involved in bile regulation of ToxT activity, (iii). identification of ToxT amino acids necessary for bile regulation, and (iv). determination of the effects of bile on ToxT DNA binding activity. Finally, the relevance of environmental modulation of ToxT activity (by bile or other stimuli) will be assessed by testing the virulent properties of K cholerae strains containing mutations which affect various aspects of ToxT transcription. Our ultimate goal is to learn how to manipulate ToxT by external factors in order to repress virulence gene expression and prevent cholera, i.e. to force V. cholerae to prevent itself from causing disease. This fundamentally different approach to cholera therapy should lead to novel antimicrobial strategies mimicking the effects of bile which will be useful in combating cholera.
DESCRIPTION (provided by applicant): Cholera is an often-fatal diarrheal disease caused by the bacterium Vibrio cholerae. This disease remains a health threat for the majority of the world, causing thousands of deaths every year. We have recently demonstrated that ToxT, the primary transcriptional activator of virulence genes in V. cholerae, is negatively regulated by certain environmental signals, and specifically by the presence of bile. Our studies will focus on dissecting the molecular mechanism(s) of environmental modulation of ToxT transcriptional activity, utilizing bile as an environmental modulatory factor. We wish to understand and exploit this negative regulation to develop novel means to prevent cholera. Essentially nothing is known about the structure/function of ToxT, so these studies also include the elucidation of the functions of the ToxT protein. Our approach first involves characterizing the domain structure of ToxT. This will be accomplished by (i). construction and characterization of chimeric ToxT proteins, and (ii). identification of ToxT amino acids important for DNA binding and transcriptional activation. Further characterization of ToxT will include the identification of all the ToxT-regulated genes of V. cholerae by microarray analysis, and the characterization of the ToxT DNA binding site(s). Once we have a more thorough understanding of ToxT, we will determine the mechanism of modulation of ToxT transcriptional activity by environmental signals, utilizing bile as the modulatory factor. These studies include: (i). determination of the effect of the porins OmpU and OmpT (which are known to be differentially permeable to bile) on bile modulation of ToxT activity, (ii). identification of additional V. cholerae genes involved in bile regulation of ToxT activity, (iii). Identification of ToxT amino acids necessary for bile regulation, and (iv). determination of the effects of bile on ToxT DNA binding activity. Finally, the relevance of environmental modulation of ToxT activity (by bile or other stimuli) will be assessed by testing the virulent properties of V. cholerae strains containing mutations that affect various aspects of ToxT transcription. Our ultimate goal is to learn how to manipulate ToxT by external factors in order to repress virulence gene expression and prevent cholera, i.e., to force V. cholerae to prevent itself from causing disease. This fundamentally different approach to cholera therapy could lead to novel antimicrobial strategies mimicking the effects of bile.
DESCRIPTION (provided by applicant): Background: U.S. citizens, particularly military personnel, are vulnerable to the threat of exposure to biological warfare agents. Two such bacterial agents, Bacillus anthracis and Francisella tularensis, can be easily spread by aerosolization causing a high level of mortality, and are therefore considered to be candidate warfare agents. New vaccines against these and other potential warfare agents are needed which can be easily administered and provide high levels of protection against aerosolized bio-weapons. We have developed a Salmonella typhimurium strain (delta-glnA delta-glnH) with a number of attributes that make it an attractive candidate for a live attenuated multivalent vaccine. Our hypothesis is that this attenuated S. typhimurium strain can be used as a single oral vaccine to deliver multivalent antigens and provide both mucosal and systemic protective immunity against aerosolized biological warfare agents, specifically B. anthracis and F. tularensis. We will exploit specific S. typhimurium promoters (e.g., pmrH) to drive high-level expression of B. anthracis and F. tularensis antigens within the lymphoid tissue, and thus generate a sufficient immune response with a single dose. The Specific Aims of this project entail: (1) Construction of delta-glnA delta-glnH attenuated S. typhimurium vaccine strains with the pmrH promoter driving expression of B. anthracis. Protective Antigen (PA) and F. tularensis FopA and TUL4 proteins; (2) Evaluation of the efficacy of vaccine strains (Specific Aim 1) to express heterologous antigens within immune tissue and elicit an appropriate immune response; and (3) Challenge vaccinated animals with aerosolized B. anthracis and F. tularensis to determine efficacy of the vaccine strains. Our Study Design incorporates collaborative vaccine development at three different sites in San Antonio, based upon the expertise found at each site. The S. typhimurium vaccine strains expressing B. anthracis and F. tularensis antigens will be constructed and inoculated into animals in the laboratories of two S. typhimurium researchers, Drs. Karl Klose and John Gunn, at the University of Texas Health Science Center. The evaluation of levels of antigen expression within immune tissue will be carried out at the Brooks Air Force Base by Dr. Kenton Lohman. Aerosolized B. anthracis and F. tularensis challenge studies of vaccinated animals will take place in the Biosafety Level 4 (BSL-4) laboratory at the Southwest Foundation for Biomedical Research under the guidance of Dr. Jean Patterson. We will be taking advantage of this high-level biocontainment laboratory to perform the aerosol challenges necessary to prove the efficacy of this vaccine approach. Relevance: The development of a single oral vaccine that can simultaneously provide protection against multiple bio-warfare agents would be of tremendous benefit to the health of military personnel and other citizens exposed to these agents. If this vaccine strategy proves successful, additional antigens can be expressed from the same vaccine strain, offering an adaptive and protective health tool.
DESCRIPTION (Adapted from the Applicant's Abstract): Vibrio cholerae, the causative agent of the human diarrheal disease cholera, can be considered to have a pathogenic cycle consisting of a highly motile phase outside the host when no virulence factors are produced, and a colonizing phase within the host intestine when high levels of virulence factors are expressed. Little is known about the requirements for colonization or the environmental conditions which induce virulence factor expression. The investigators have recently found that the alternative sigma factor, sigma 54, and a sigma 54-dependent transcriptional activator protein, FlrC, are required for the expression of distinct sets of genes during both phases of the pathogenic cycle. Moreover, FlrC apparently plays a crucial role in this cycle by simultaneously activating motility genes and repressing virulence factor expression. The experiments in this proposal are focused on the characterization of sigma 54 and FlrC-mediated transcription in V. cholerae, given their important role in the cholera pathogenic cycle. Such studies will provide insights into the molecular mechanisms of pathogenicity, which may lead to novel methods for treatment and prevention of cholera, as well as other infectious diseases. Studies of FlrC function are designed to characterize its 1) phosphorylation, ii) enzymatic (ATPase) activity, iii) DNA-binding, iv) cooperative interactions and v) transcriptional activity. A series of genetic experiments are designed to identify the interactions between FlrC and the virulence regulatory proteins that lead to 1) repression of virulence factor expression and 2) repression of motility gene transcription. Finally, FlrC-controlled genes will be identified by first identifying FlrC binding sites, which lie near the genes FlrC controls, utilizing a technique which involves cycles of selection for FlrC-bound chromosomal fragments followed by PCR amplification. Sequencing the DNA surrounding the selected FlrC binding sites will identify those motility and colonization genes under FlrC control, and the mechanism whereby flrC represses virulence factor production will be revealed. Identification of sigma 54 and FlrC-dependent colonization genes and promoters may be useful in the development of live attenuated cholera vaccines, and manipulation of virulence factor repression could have practical applications for anti-cholera therapy.
1. Echazarreta MA, Kepple JL, Yen LH, Chen Y, Klose KE. A Critical Region in the FlaA Flagellin Facilitates Filament Formation of the Vibrio cholerae Flagellum. J Bacteriol. 2018 Mar 26.
2. Allué-Guardia A, Echazarreta M, Koenig SSK, Klose KE, Eppinger M. Closed Genome Sequence of Vibrio cholerae O1 El Tor Inaba Strain A1552. Genome Announc. 2018 Mar 01; 6(9).
3. Nguyen JQ, Zogaj X, Adelani AA, Chu P, Yu JJ, Arulanandam BP, Klose KE. Intratracheal Inoculation of Fischer 344 Rats with Francisella tularensis. J Vis Exp. 2017 09 30; (127).
4. Sarva ST, Waldo RH, Belland RJ, Klose KE. Comparative Transcriptional Analyses of Francisella tularensis and Francisella novicida. PLoS One. 2016; 11(8):e0158631.
5. Cunningham AL, Guentzel MN, Yu JJ, Hung CY, Forsthuber TG, Navara CS, Yagita H, Williams IR, Klose KE, Eaves-Pyles TD, Arulanandam BP. M-Cells Contribute to the Entry of an Oral Vaccine but Are Not Essential for the Subsequent Induction of Protective Immunity against Francisella tularensis. PLoS One. 2016; 11(4):e0153402.
6. Chu P, Cunningham AL, Yu JJ, Nguyen JQ, Barker JR, Lyons CR, Wilder J, Valderas M, Sherwood RL, Arulanandam BP, Klose KE. Live attenuated Francisella novicida vaccine protects against Francisella tularensis pulmonary challenge in rats and non-human primates. PLoS Pathog. 2014 Oct; 10(10):e1004439.
7. Mazel D, Colwell R, Klose K, Oliver J, Crumlish M, McDougald D, Bland MJ, Austin B. VIBRIO 2014 meeting report. Res Microbiol. 2014 Dec; 165(10):857-64.
8. Weber GG, Kortmann J, Narberhaus F, Klose KE. RNA thermometer controls temperature-dependent virulence factor expression in Vibrio cholerae. Proc Natl Acad Sci U S A. 2014 Sep 30; 111(39):14241-6.
9. Cunningham AL, Dang KM, Yu JJ, Guentzel MN, Heidner HW, Klose KE, Arulanandam BP. Enhancement of vaccine efficacy by expression of a TLR5 ligand in the defined live attenuated Francisella tularensis subsp. novicida strain U112?iglB::fljB. Vaccine. 2014 Sep 08; 32(40):5234-40.
10. Nguyen JQ, Gilley RP, Zogaj X, Rodriguez SA, Klose KE. Lipidation of the FPI protein IglE contributes to Francisella tularensis ssp. novicida intramacrophage replication and virulence. Pathog Dis. 2014 Oct; 72(1):10-8.
11. Jubair M, Atanasova KR, Rahman M, Klose KE, Yasmin M, Yilmaz O, Morris JG, Ali A. Vibrio cholerae persisted in microcosm for 700 days inhibits motility but promotes biofilm formation in nutrient-poor lake water microcosms. PLoS One. 2014; 9(3):e92883.
12. Eppinger M, McNair K, Zogaj X, Dinsdale EA, Edwards RA, Klose KE. Draft Genome Sequence of the Fish Pathogen Piscirickettsia salmonis. Genome Announc. 2013 Nov 07; 1(6).
13. Miner KD, Klose KE, Kurtz DM. An HD-GYP cyclic di-guanosine monophosphate phosphodiesterase with a non-heme diiron-carboxylate active site. Biochemistry. 2013 Aug 13; 52(32):5329-31.
14. Signarovitz AL, Ray HJ, Yu JJ, Guentzel MN, Chambers JP, Klose KE, Arulanandam BP. Mucosal immunization with live attenuated Francisella novicida U112?iglB protects against pulmonary F. tularensis SCHU S4 in the Fischer 344 rat model. PLoS One. 2012; 7(10):e47639.
15. Schaller RA, Ali SK, Klose KE, Kurtz DM. A bacterial hemerythrin domain regulates the activity of a Vibrio cholerae diguanylate cyclase. Biochemistry. 2012 Oct 30; 51(43):8563-70.
16. Zogaj X, Wyatt GC, Klose KE. Cyclic di-GMP stimulates biofilm formation and inhibits virulence of Francisella novicida. Infect Immun. 2012 Dec; 80(12):4239-47.
17. Arulanandam BP, Chetty SL, Yu JJ, Leonard S, Klose K, Seshu J, Cap A, Valdes JJ, Chambers JP. Francisella DnaK inhibits tissue-nonspecific alkaline phosphatase. J Biol Chem. 2012 Oct 26; 287(44):37185-94.
18. Rodriguez AR, Yu JJ, Guentzel MN, Navara CS, Klose KE, Forsthuber TG, Chambers JP, Berton MT, Arulanandam BP. Mast cell TLR2 signaling is crucial for effective killing of Francisella tularensis. J Immunol. 2012 Jun 01; 188(11):5604-11.
19. Sanapala S, Yu JJ, Murthy AK, Li W, Guentzel MN, Chambers JP, Klose KE, Arulanandam BP. Perforin- and granzyme-mediated cytotoxic effector functions are essential for protection against Francisella tularensis following vaccination by the defined F. tularensis subsp. novicida ?fopC vaccine strain. Infect Immun. 2012 Jun; 80(6):2177-85.
20. Hankins JV, Madsen JA, Giles DK, Childers BM, Klose KE, Brodbelt JS, Trent MS. Elucidation of a novel Vibrio cholerae lipid A secondary hydroxy-acyltransferase and its role in innate immune recognition. Mol Microbiol. 2011 Sep; 81(5):1313-29.
21. Childers BM, Cao X, Weber GG, Demeler B, Hart PJ, Klose KE. N-terminal residues of the Vibrio cholerae virulence regulatory protein ToxT involved in dimerization and modulation by fatty acids. J Biol Chem. 2011 Aug 12; 286(32):28644-55.
22. Chu P, Rodriguez AR, Arulanandam BP, Klose KE. Tryptophan prototrophy contributes to Francisella tularensis evasion of gamma interferon-mediated host defense. Infect Immun. 2011 Jun; 79(6):2356-61.
23. Nallaparaju KC, Yu JJ, Rodriguez SA, Zogaj X, Manam S, Guentzel MN, Seshu J, Murthy AK, Chambers JP, Klose KE, Arulanandam BP. Evasion of IFN-? signaling by Francisella novicida is dependent upon Francisella outer membrane protein C. PLoS One. 2011 Mar 31; 6(3):e18201.
24. Murthy AK, Chaganty BK, Troutman T, Guentzel MN, Yu JJ, Ali SK, Lauriano CM, Chambers JP, Klose KE, Arulanandam BP. Mannose-containing oligosaccharides of non-specific human secretory immunoglobulin A mediate inhibition of Vibrio cholerae biofilm formation. PLoS One. 2011 Feb 09; 6(2):e16847.
25. Weber GG, Klose KE. The complexity of ToxT-dependent transcription in Vibrio cholerae. Indian J Med Res. 2011 Feb; 133:201-6.
26. Zogaj X, Klose KE. Genetic manipulation of francisella tularensis. Front Microbiol. 2010; 1:142.
27. Karna SL, Zogaj X, Barker JR, Seshu J, Dove SL, Klose KE. A bacterial two-hybrid system that utilizes Gateway cloning for rapid screening of protein-protein interactions. Biotechniques. 2010 Nov; 49(5):831-3.
28. Rodriguez AR, Yu JJ, Murthy AK, Guentzel MN, Klose KE, Forsthuber TG, Chambers JP, Berton MT, Arulanandam BP. Mast cell/IL-4 control of Francisella tularensis replication and host cell death is associated with increased ATP production and phagosomal acidification. Mucosal Immunol. 2011 Mar; 4(2):217-26.
29. Thompson FL, Thompson CC, Vicente AC, Klose KE. Vibrio2009: the third international conference on the biology of Vibrios. Mol Microbiol. 2010 Sep; 77(5):1065-71.
30. Fong JC, Syed KA, Klose KE, Yildiz FH. Role of Vibrio polysaccharide (vps) genes in VPS production, biofilm formation and Vibrio cholerae pathogenesis. Microbiology. 2010 Sep; 156(Pt 9):2757-69.
31. Ray HJ, Chu P, Wu TH, Lyons CR, Murthy AK, Guentzel MN, Klose KE, Arulanandam BP. The Fischer 344 rat reflects human susceptibility to francisella pulmonary challenge and provides a new platform for virulence and protection studies. PLoS One. 2010 Apr 01; 5(4):e9952.
32. Yu JJ, Goluguri T, Guentzel MN, Chambers JP, Murthy AK, Klose KE, Forsthuber TG, Arulanandam BP. Francisella tularensis T-cell antigen identification using humanized HLA-DR4 transgenic mice. Clin Vaccine Immunol. 2010 Feb; 17(2):215-22.
33. Barker JR, Chong A, Wehrly TD, Yu JJ, Rodriguez SA, Liu J, Celli J, Arulanandam BP, Klose KE. The Francisella tularensis pathogenicity island encodes a secretion system that is required for phagosome escape and virulence. Mol Microbiol. 2009 Dec; 74(6):1459-70.
34. Chaparro AP, Ali SK, Klose KE. The ToxT-dependent methyl-accepting chemoreceptors AcfB and TcpI contribute to Vibrio cholerae intestinal colonization. FEMS Microbiol Lett. 2010 Jan; 302(2):99-105.
35. Moisi M, Jenul C, Butler SM, New A, Tutz S, Reidl J, Klose KE, Camilli A, Schild S. A novel regulatory protein involved in motility of Vibrio cholerae. J Bacteriol. 2009 Nov; 191(22):7027-38.
36. Syed KA, Beyhan S, Correa N, Queen J, Liu J, Peng F, Satchell KJ, Yildiz F, Klose KE. The Vibrio cholerae flagellar regulatory hierarchy controls expression of virulence factors. J Bacteriol. 2009 Nov; 191(21):6555-70.
37. Cong Y, Yu JJ, Guentzel MN, Berton MT, Seshu J, Klose KE, Arulanandam BP. Vaccination with a defined Francisella tularensis subsp. novicida pathogenicity island mutant (DeltaiglB) induces protective immunity against homotypic and heterotypic challenge. Vaccine. 2009 Sep 18; 27(41):5554-61.
38. Rodriguez SA, Davis G, Klose KE. Targeted gene disruption in Francisella tularensis by group II introns. Methods. 2009 Nov; 49(3):270-4.
39. Ray HJ, Cong Y, Murthy AK, Selby DM, Klose KE, Barker JR, Guentzel MN, Arulanandam BP. Oral live vaccine strain-induced protective immunity against pulmonary Francisella tularensis challenge is mediated by CD4+ T cells and antibodies, including immunoglobulin A. Clin Vaccine Immunol. 2009 Apr; 16(4):444-52.
40. Sorci L, Martynowski D, Rodionov DA, Eyobo Y, Zogaj X, Klose KE, Nikolaev EV, Magni G, Zhang H, Osterman AL. Nicotinamide mononucleotide synthetase is the key enzyme for an alternative route of NAD biosynthesis in Francisella tularensis. Proc Natl Acad Sci U S A. 2009 Mar 03; 106(9):3083-8.
41. Chatterjee S, Ghosh K, Raychoudhuri A, Chowdhury G, Bhattacharya MK, Mukhopadhyay AK, Ramamurthy T, Bhattacharya SK, Klose KE, Nandy RK. Incidence, virulence factors, and clonality among clinical strains of non-O1, non-O139 Vibrio cholerae isolates from hospitalized diarrheal patients in Kolkata, India. J Clin Microbiol. 2009 Apr; 47(4):1087-95.
42. Chong A, Wehrly TD, Nair V, Fischer ER, Barker JR, Klose KE, Celli J. The early phagosomal stage of Francisella tularensis determines optimal phagosomal escape and Francisella pathogenicity island protein expression. Infect Immun. 2008 Dec; 76(12):5488-99.
43. Zogaj X, Chakraborty S, Liu J, Thanassi DG, Klose KE. Characterization of the Francisella tularensis subsp. novicida type IV pilus. Microbiology. 2008 Jul; 154(Pt 7):2139-50.
44. Ketavarapu JM, Rodriguez AR, Yu JJ, Cong Y, Murthy AK, Forsthuber TG, Guentzel MN, Klose KE, Berton MT, Arulanandam BP. Mast cells inhibit intramacrophage Francisella tularensis replication via contact and secreted products including IL-4. Proc Natl Acad Sci U S A. 2008 Jul 08; 105(27):9313-8.
45. Mohapatra NP, Soni S, Reilly TJ, Liu J, Klose KE, Gunn JS. Combined deletion of four Francisella novicida acid phosphatases attenuates virulence and macrophage vacuolar escape. Infect Immun. 2008 Aug; 76(8):3690-9.
46. Powell HJ, Cong Y, Yu JJ, Guentzel MN, Berton MT, Klose KE, Murthy AK, Arulanandam BP. CD4+ T cells are required during priming but not the effector phase of antibody-mediated IFN-gamma-dependent protective immunity against pulmonary Francisella novicida infection. Immunol Cell Biol. 2008 Aug-Sep; 86(6):515-22.
47. Rodriguez SA, Yu JJ, Davis G, Arulanandam BP, Klose KE. Targeted inactivation of francisella tularensis genes by group II introns. Appl Environ Microbiol. 2008 May; 74(9):2619-26.
48. Yu JJ, Raulie EK, Murthy AK, Guentzel MN, Klose KE, Arulanandam BP. The presence of infectious extracellular Francisella tularensis subsp. novicida in murine plasma after pulmonary challenge. Eur J Clin Microbiol Infect Dis. 2008 Apr; 27(4):323-5.
49. Morris DC, Peng F, Barker JR, Klose KE. Lipidation of an FlrC-dependent protein is required for enhanced intestinal colonization by Vibrio cholerae. J Bacteriol. 2008 Jan; 190(1):231-9.
50. Liu J, Zogaj X, Barker JR, Klose KE. Construction of targeted insertion mutations in Francisella tularensis subsp. novicida. Biotechniques. 2007 Oct; 43(4):487-90, 492.
51. Waldo RH, Cummings ED, Sarva ST, Brown JM, Lauriano CM, Rose LA, Belland RJ, Klose KE, Hilliard GM. Proteome cataloging and relative quantification of Francisella tularensis tularensis strain Schu4 in 2D PAGE using preparative isoelectric focusing. J Proteome Res. 2007 Sep; 6(9):3484-90.
52. Childers BM, Klose KE. Regulation of virulence in Vibrio cholerae: the ToxR regulon. Future Microbiol. 2007 Jun; 2(3):335-44.
53. Santic M, Molmeret M, Barker JR, Klose KE, Dekanic A, Doric M, Abu Kwaik Y. A Francisella tularensis pathogenicity island protein essential for bacterial proliferation within the host cell cytosol. Cell Microbiol. 2007 Oct; 9(10):2391-403.
54. Barker JR, Klose KE. Molecular and genetic basis of pathogenesis in Francisella tularensis. Ann N Y Acad Sci. 2007 Jun; 1105:138-59.
55. Childers BM, Weber GG, Prouty MG, Castaneda MM, Peng F, Klose KE. Identification of residues critical for the function of the Vibrio cholerae virulence regulator ToxT by scanning alanine mutagenesis. J Mol Biol. 2007 Apr 13; 367(5):1413-30.
56. Xicohtencatl-Cortés J, Lyons S, Chaparro AP, Hernández DR, Saldaña Z, Ledesma MA, Rendón MA, Gewirtz AT, Klose KE, Girón JA. Identification of proinflammatory flagellin proteins in supernatants of Vibrio cholerae O1 by proteomics analysis. Mol Cell Proteomics. 2006 Dec; 5(12):2374-83.
57. Thompson FL, Klose KE. Vibrio2005: the First International Conference on the Biology of Vibrios. J Bacteriol. 2006 Jul; 188(13):4592-6.
58. Pammit MA, Raulie EK, Lauriano CM, Klose KE, Arulanandam BP. Intranasal vaccination with a defined attenuated Francisella novicida strain induces gamma interferon-dependent antibody-mediated protection against tularemia. Infect Immun. 2006 Apr; 74(4):2063-71.
59. Klose KE. Increased chatter: cyclic dipeptides as molecules of chemical communication in Vibrio spp. J Bacteriol. 2006 Mar; 188(6):2025-6.
60. Santic M, Molmeret M, Klose KE, Abu Kwaik Y. Francisella tularensis travels a novel, twisted road within macrophages. Trends Microbiol. 2006 Jan; 14(1):37-44.
61. Prouty MG, Osorio CR, Klose KE. Characterization of functional domains of the Vibrio cholerae virulence regulator ToxT. Mol Microbiol. 2005 Nov; 58(4):1143-56.
62. Correa NE, Peng F, Klose KE. Roles of the regulatory proteins FlhF and FlhG in the Vibrio cholerae flagellar transcription hierarchy. J Bacteriol. 2005 Sep; 187(18):6324-32.
63. Schild S, Lamprecht AK, Fourestier C, Lauriano CM, Klose KE, Reidl J. Characterizing lipopolysaccharide and core lipid A mutant O1 and O139 Vibrio cholerae strains for adherence properties on mucus-producing cell line HT29-Rev MTX and virulence in mice. Int J Med Microbiol. 2005 Aug; 295(4):243-51.
64. Santic M, Molmeret M, Klose KE, Jones S, Kwaik YA. The Francisella tularensis pathogenicity island protein IglC and its regulator MglA are essential for modulating phagosome biogenesis and subsequent bacterial escape into the cytoplasm. Cell Microbiol. 2005 Jul; 7(7):969-79.
65. Correa NE, Klose KE. Characterization of enhancer binding by the Vibrio cholerae flagellar regulatory protein FlrC. J Bacteriol. 2005 May; 187(9):3158-70.
66. Kern WV, Klose K, Jellen-Ritter AS, Oethinger M, Bohnert J, Kern P, Reuter S, von Baum H, Marre R. Fluoroquinolone resistance of Escherichia coli at a cancer center: epidemiologic evolution and effects of discontinuing prophylactic fluoroquinolone use in neutropenic patients with leukemia. Eur J Clin Microbiol Infect Dis. 2005 Feb; 24(2):111-8.
67. Pammit MA, Budhavarapu VN, Raulie EK, Klose KE, Teale JM, Arulanandam BP. Intranasal interleukin-12 treatment promotes antimicrobial clearance and survival in pulmonary Francisella tularensis subsp. novicida infection. Antimicrob Agents Chemother. 2004 Dec; 48(12):4513-9.
68. Nano FE, Zhang N, Cowley SC, Klose KE, Cheung KK, Roberts MJ, Ludu JS, Letendre GW, Meierovics AI, Stephens G, Elkins KL. A Francisella tularensis pathogenicity island required for intramacrophage growth. J Bacteriol. 2004 Oct; 186(19):6430-6.
69. Lauriano CM, Ghosh C, Correa NE, Klose KE. The sodium-driven flagellar motor controls exopolysaccharide expression in Vibrio cholerae. J Bacteriol. 2004 Aug; 186(15):4864-74.
70. Correa NE, Barker JR, Klose KE. The Vibrio cholerae FlgM homologue is an anti-sigma28 factor that is secreted through the sheathed polar flagellum. J Bacteriol. 2004 Jul; 186(14):4613-9.
71. Lauriano CM, Barker JR, Yoon SS, Nano FE, Arulanandam BP, Hassett DJ, Klose KE. MglA regulates transcription of virulence factors necessary for Francisella tularensis intraamoebae and intramacrophage survival. Proc Natl Acad Sci U S A. 2004 Mar 23; 101(12):4246-9.
72. Lauriano CM, Barker JR, Nano FE, Arulanandam BP, Klose KE. Allelic exchange in Francisella tularensis using PCR products. FEMS Microbiol Lett. 2003 Dec 12; 229(2):195-202.
73. Hassett DJ, Limbach PA, Hennigan RF, Klose KE, Hancock RE, Platt MD, Hunt DF. Bacterial biofilms of importance to medicine and bioterrorism: proteomic techniques to identify novel vaccine components and drug targets. Expert Opin Biol Ther. 2003 Dec; 3(8):1201-7.
74. Prouty MG, Correa NE, Barker LP, Jagadeeswaran P, Klose KE. Zebrafish-Mycobacterium marinum model for mycobacterial pathogenesis. FEMS Microbiol Lett. 2003 Aug 29; 225(2):177-82.
75. Simonet VC, Baslé A, Klose KE, Delcour AH. The Vibrio cholerae porins OmpU and OmpT have distinct channel properties. J Biol Chem. 2003 May 09; 278(19):17539-45.
76. Nesper J, Schild S, Lauriano CM, Kraiss A, Klose KE, Reidl J. Role of Vibrio cholerae O139 surface polysaccharides in intestinal colonization. Infect Immun. 2002 Nov; 70(11):5990-6.
77. Reidl J, Klose KE. Vibrio cholerae and cholera: out of the water and into the host. FEMS Microbiol Rev. 2002 Jun; 26(2):125-39.
78. Nesper J, Kraiss A, Schild S, Blass J, Klose KE, Bockemühl J, Reidl J. Comparative and genetic analyses of the putative Vibrio cholerae lipopolysaccharide core oligosaccharide biosynthesis (wav) gene cluster. Infect Immun. 2002 May; 70(5):2419-33.
79. Wibbenmeyer JA, Provenzano D, Landry CF, Klose KE, Delcour AH. Vibrio cholerae OmpU and OmpT porins are differentially affected by bile. Infect Immun. 2002 Jan; 70(1):121-6.
80. Julio SM, Heithoff DM, Provenzano D, Klose KE, Sinsheimer RL, Low DA, Mahan MJ. DNA adenine methylase is essential for viability and plays a role in the pathogenesis of Yersinia pseudotuberculosis and Vibrio cholerae. Infect Immun. 2001 Dec; 69(12):7610-5.
81. Provenzano D, Lauriano CM, Klose KE. Characterization of the role of the ToxR-modulated outer membrane porins OmpU and OmpT in Vibrio cholerae virulence. J Bacteriol. 2001 Jun; 183(12):3652-62.
82. Klose KE. Regulation of virulence in Vibrio cholerae. Int J Med Microbiol. 2001 May; 291(2):81-8.
83. Prouty MG, Correa NE, Klose KE. The novel sigma54- and sigma28-dependent flagellar gene transcription hierarchy of Vibrio cholerae. Mol Microbiol. 2001 Mar; 39(6):1595-609.
84. Nesper J, Lauriano CM, Klose KE, Kapfhammer D, Kraiss A, Reidl J. Characterization of Vibrio cholerae O1 El tor galU and galE mutants: influence on lipopolysaccharide structure, colonization, and biofilm formation. Infect Immun. 2001 Jan; 69(1):435-45.

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