Search

Your search keyword '"Llewellyn, Anna C."' showing total 14 results
Start Over Author "Llewellyn, Anna C."

Refine your results

more »

more »

more »

more »
14 results on '"Llewellyn, Anna C."'

1. Lessons from the reestablishment of Public Health Laboratory activities in Puerto Rico after Hurricane Maria

Author

Hardy, Margaret C., Stinnett, Rita C., Kines, Kristine J., Rivera-Nazario, Danisha M., Lowe, David E., Mercante, Alexandra M., Gonzalez Jimenez, Nathalie, Cuevas Ruiz, Rosa I., Rivera Arbolay, Héctor I., Gonzalez Peña, Rafael L., Toro, Mayra, Trujillo, Alma A., Pappas, Claudia L., Llewellyn, Anna C., Candal, Francisco, Burgos Garay, María, Gomez, Gerardo A., Concepcion Acevedo, Jeniffer, Ansbro, Marisela, Moura, Hercules, Shaw, Michael W., Muehlenbachs, Atis, Romanoff, Lovisa C., Sunshine, Brittany J., Rose, Dale A., Patel, Anita, Shapiro, Craig N., Luna-Pinto, S. Carolina, Pillai, Satish K., and O’Neill, Eduardo

Published
2019
Full Text
View/download PDF

4. A CRISPR/Cas system mediates bacterial innate immune evasion and virulence

Author

Sampson, Timothy R., Saroj, Sunil D., Llewellyn, Anna C., Tzeng, Yih-Ling, and Weiss, David S.

Subjects
Virulence (Microbiology) -- Research, Immune response -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

CRISPR/Cas (clustered regularly interspaced palindromic repeats/CRISPR-associated) systems are a bacterial defence against invading foreign nucleic acids derived from bacteriophages or exogenous plasmids (1-4). These systems use an array of small [...]

Published
2013
Full Text
View/download PDF

6. Francisella FlmX broadly affects lipopolysaccharide modification and virulence

Author

Chin, Chui-Yoke, Zhao, Jinshi, Llewellyn, Anna C., Golovliov, Igor, Sjöstedt, Anders, Zhou, Pei, Weiss, David S., Chin, Chui-Yoke, Zhao, Jinshi, Llewellyn, Anna C., Golovliov, Igor, Sjöstedt, Anders, Zhou, Pei, and Weiss, David S.

Abstract

The outer membrane protects Gram-negative bacteria from the host environment. Lipopolysaccharide (LPS), a major outer membrane constituent, has distinct components (lipid A, core, O-antigen) generated by specialized pathways. In this study, we describe the surprising convergence of these pathways through FlmX, an uncharacterized protein in the intracellular pathogen Francisella. FlmX is in the flippase family, which includes proteins that traffic lipid-linked envelope components across membranes. flmX deficiency causes defects in lipid A modification, core remodeling, and O-antigen addition. We find that an F. tularensis mutant lacking flmX is >1,000,000-fold attenuated. Furthermore, FlmX is required to resist the innate antimicrobial LL-37 and the antibiotic polymyxin. Given FlmX's central role in LPS modification and its conservation in intracellular pathogens Brucella, Coxiella, and Legionella, FlmX may represent a novel drug target whose inhibition could cripple bacterial virulence and sensitize bacteria to innate antimicrobials and antibiotics.

Published
2021
Full Text
View/download PDF

9. NaxD is a deacetylase required for lipid A modification and Francisella pathogenesis

Author

Laroui, Hamed, Xu, Qian, Bina, James E., Raetz, Christian R. H., Miller, Mark A., Parvathareddy, Jyothi, Zhao, Jinshi, Napier, Brooke A., Cotter, Peggy A., Merlin, Didier, Weiss, David S., Llewellyn, Anna C., and Song, Feng

Subjects
Virulence, Macrophages, Article, Amidohydrolases, Cell Line, Mice, Inbred C57BL, Mice, Lipid A, Bacterial Proteins, Animals, Humans, Female, Francisella, Francisella tularensis, Gram-Negative Bacterial Infections, Sequence Alignment
Abstract

Modification of specific Gram-negative bacterial cell envelope components, such as capsule, O-antigen and lipid A, are often essential for the successful establishment of infection. Francisella species express lipid A molecules with unique characteristics involved in circumventing host defences, which significantly contribute to their virulence. In this study, we show that NaxD, a member of the highly conserved YdjC superfamily, is a deacetylase required for an important modification of the outer membrane component lipid A in Francisella. Mass spectrometry analysis revealed that NaxD is essential for the modification of a lipid A phosphate with galactosamine in Francisella novicida, a model organism for the study of highly virulent Francisella tularensis. Significantly, enzymatic assays confirmed that this protein is necessary for deacetylation of its substrate. In addition, NaxD was involved in resistance to the antimicrobial peptide polymyxin B and critical for replication in macrophages and in vivo virulence. Importantly, this protein is also required for lipid A modification in F. tularensis as well as Bordetella bronchiseptica. Since NaxD homologues are conserved among many Gram-negative pathogens, this work has broad implications for our understanding of host subversion mechanisms of other virulent bacteria.

Published
2012

10. Corrigendum: a CRISPR/Cas system mediates bacterial innate immune evasion and virulence

Author

Sampson, Timothy R., Saroj, Sunil D., Llewellyn, Anna C., Tzeng, Yih-Ling, and Weiss, David S.

Subjects
Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Nature 497, 254-257 (2013); doi:10.1038/nature12048 In this Letter, we described two small RNAs (scaRNA and tracrRNA) within the Francisella novicida CRISPR/Cas locus that are necessary for repression of an endogenous [...]

Published
2013
Full Text
View/download PDF

14. FrancisellaFlmX broadly affects lipopolysaccharide modification and virulence

Author

Chin, Chui-Yoke, Zhao, Jinshi, Llewellyn, Anna C., Golovliov, Igor, Sjöstedt, Anders, Zhou, Pei, and Weiss, David S.

Abstract

The outer membrane protects Gram-negative bacteria from the host environment. Lipopolysaccharide (LPS), a major outer membrane constituent, has distinct components (lipid A, core, O-antigen) generated by specialized pathways. In this study, we describe the surprising convergence of these pathways through FlmX, an uncharacterized protein in the intracellular pathogen Francisella. FlmX is in the flippase family, which includes proteins that traffic lipid-linked envelope components across membranes. flmXdeficiency causes defects in lipid A modification, core remodeling, and O-antigen addition. We find that an F. tularensismutant lacking flmXis >1,000,000-fold attenuated. Furthermore, FlmX is required to resist the innate antimicrobial LL-37 and the antibiotic polymyxin. Given FlmX’s central role in LPS modification and its conservation in intracellular pathogens Brucella, Coxiella, and Legionella, FlmX may represent a novel drug target whose inhibition could cripple bacterial virulence and sensitize bacteria to innate antimicrobials and antibiotics.

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results