Phoom Chairatana

Phoom Chairatana
Faculty of Medicine Siriraj Hospital · Department of Microbiology

Doctor of Philosophy

About

17
Publications
2,004
Reads
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465
Citations
Additional affiliations
June 2016 - September 2016
Massachusetts Institute of Technology
Position
  • PostDoc Position
May 2009 - July 2009
University of Oxford
Position
  • Student

Publications

Publications (17)
Article
Full-text available
Human α-defensin 5 (HD5) is a host-defense peptide exhibiting broad-spectrum antimicrobial activity. The lipopolysaccharide (LPS) layer on the Gram-negative bacterial membrane acts as a barrier to HD5 insertion. Therefore, the pore formation and binding mechanism remain unclear. Here, the binding mechanisms at five positions along the bacterial mem...
Preprint
Full-text available
Superspreader hosts carry out most pathogen transmission events and are often disease tolerant since they remain asymptomatic despite high pathogen burdens. Here we describe the superspreader immune state that allows for disease tolerance. In a model of Salmonella infection, superspreader mice develop colitis with robust CD4 ⁺ and CD8 ⁺ T-cell resp...
Article
Full-text available
The various sub-species of Salmonella enterica cause a range of disease in human hosts. The human-adapted Salmonella enterica serovar Typhi enters the gastrointestinal tract and invades systemic sites to cause enteric (typhoid) fever. In contrast, most non-typhoidal serovars of Salmonella are primarily restricted to gut tissues. Across Africa, inva...
Article
Human α -defensin 5 (HD5) is a 32-residue cysteine-rich host-defense peptide that exhibits broad-spectrum antimicrobial activity and plays an essential role in innate immunity in the human gut and other organ systems. Although its antimicrobial mechanism of action remains unclear, the high salt concentration seems to attenuate the antimicrobial fun...
Article
Full-text available
Human α-defensin 6 (HD6) is a 32-residue cysteine-rich peptide that contributes to innate immunity by protecting the host at mucosal sites. This peptide is produced in small intestinal Paneth cells, stored as an 81-residue precursor peptide named proHD6 in granules, and released into the lumen. One unusual feature of HD6 is that it lacks the broad-...
Article
HD6 is a host-defense peptide that contributes to intestinal innate immunity and mediates homeostasis at mucosal surfaces by forming non-covalent oligomers that capture bacteria and prevent bacterial invasion into the epithelium. Our present work illustrates a new role of HD6 in defending the host epithelium against pathogenic microorganisms. We re...
Article
In the intestine, the mucosal immune system plays essential roles in maintaining homeostasis between the host and microorganisms, and protecting the host from pathogenic invaders. Epithelial cells produce and release a variety of biomolecules into the mucosa and lumen that contribute to immunity. In this review, we focus on a subset of these remark...
Article
Infections with Gram-negative pathogens pose a serious threat to public health. This scenario is exacerbated by increases in antibiotic resistance and the limited availability of vaccines and therapeutic tools to combat these infections. Here, we report an immunization approach that targets siderophores, which are small molecules exported by enteri...
Article
Molecular rotors have emerged as versatile probes of microscopic viscosity in lipid bilayers, although it has proved difficult to find probes that stain both phases equally in phase-separated bilayers. Here, we investigate the use of a membrane-targeting viscosity-sensitive fluorophore based on a thiophene moiety with equal affinity for ordered and...
Thesis
The first part of this thesis focuses on studies of structural and functional properties of human defensin 6 (HD6). This peptide is produced and secreted by intestinal Paneth cells as a part of innate immune response to invading microbes. Instead of killing microbes, HD6 self-assembles into higher-order oligomers to entrap and prevent microbes from...
Article
Full-text available
Human α-defensin 6 (HD6) is a unique peptide of the defensin family that provides innate immunity in the intestine by self-assembling to form higher-order oligomers that entrap bacteria and prevent host cell invasion. Here, we report critical steps in the self-assembly pathway of HD6. We demonstrate that HD6 is localized in secretory granules of sm...
Article
Full-text available
New antibiotics are required to treat bacterial infections and counteract the emergence of antibiotic resistance. Pathogen-specific antibiotics have several advantages over broad-spectrum drugs, which include minimal perturbation to the commensal microbiota. We present a strategy for targeting antibiotics to bacterial pathogens that utilizes the sa...
Article
Full-text available
We report the synthesis of four new cationic dipolar push-pull dyes, together with an evaluation of their photophysical and photobiological characteristics pertinent to imaging membranes by fluorescence and second harmonic generation (SHG). All four dyes consist of an N,N-diethylaniline electron-donor conjugated to a pyridinium electron-acceptor vi...
Article
Human α-defensin 5 (HD5) is a 32-residue cysteine-rich host-defense peptide that exhibits broad-spectrum antimicrobial activity and contributes to innate immunity in the human gut and other organ systems. Despite many years of investigation, its antimicrobial mechanism of action remains unclear. In this work, we report that HD5ox, the oxidized form...
Article
Human α-defensin 6 (HD6) is a 32-aa cysteine-rich peptide of the innate immune system. Although HD6 is a member of an antimicrobial peptide family, it exhibits negligible antibacterial activity in vitro. Rather, HD6 possesses a unique innate immune mechanism whereby it self-assembles into oligomers that capture pathogens to prevent microbial invasi...
Article
2-Acetamido-1,2-dideoxy-D-galacto-nojirimycin [DGJNAc], prepared in 20% overall yield from D-glucuronolactone, is the first potent competitive sub-micromolar inhibitor of alpha-N-acetyl-galactosaminidases (K(i) 0.081 mu M from chicken liver, K(i) 0.136 mu M from Charonia lampas). DGJNAc is a good competitive-whereas the enantiomer L-DGJNAc is a ver...

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