Journal Article
- Burkholderia thailandensis outer membrane vesicles exert antimicrobial activity against drug-resistant and competitor microbial species
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Yihui Wang , Joseph P. Hoffmann , Chau-Wen Chou , Kerstin Höner zu Bentrup , Joseph A. Fuselier , Jacob P. Bitoun , William C. Wimley , Lisa A. Morici
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J. Microbiol. 2020;58(7):550-562. Published online April 11, 2020
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DOI: https://doi.org/10.1007/s12275-020-0028-1
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Abstract
- Gram-negative bacteria secrete outer membrane vesicles
(OMVs) that play critical roles in intraspecies, interspecies,
and bacteria-environment interactions. Some OMVs, such
as those produced by Pseudomonas aeruginosa, have previously
been shown to possess antimicrobial activity against
competitor species. In the current study, we demonstrate that
OMVs from Burkholderia thailandensis inhibit the growth
of drug-sensitive and drug-resistant bacteria and fungi. We
show that a number of antimicrobial compounds, including
peptidoglycan hydrolases, 4-hydroxy-3-methyl-2-(2-nonenyl)-
quinoline (HMNQ) and long-chain rhamnolipid are
present in or tightly associate with B. thailandensis OMVs.
Furthermore, we demonstrate that HMNQ and rhamnolipid
possess antimicrobial and antibiofilm properties against methicillin-
resistant Staphylococcus aureus (MRSA). These findings
indicate that B. thailandensis secretes antimicrobial OMVs
that may impart a survival advantage by eliminating competition.
In addition, bacterial OMVs may represent an untapped
resource of novel therapeutics effective against biofilm-
forming and multidrug-resistant organisms.
Research Support, Non-U.S. Gov't
- Clades of γ-Glutamyltransferases (GGTs) in the Ascomycota and Heterologous Expression of Colletotrichum graminicola CgGGT1, a Member of the Pezizomycotina-only GGT Clade
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Marco H. Bello , Lynn Epstein
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J. Microbiol. 2013;51(1):88-99. Published online March 2, 2013
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DOI: https://doi.org/10.1007/s12275-013-2434-0
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Abstract
- Gamma-glutamyltransferase (GGT, EC 2.3.2.2) cleaves the γ-glutamyl linkage in glutathione (GSH). Ascomycetes in either the Saccharomycotina or the Taphrinomycotina have one to three GGTs, whereas members of the Pezizomycotina have two to four GGTs. A Bayesian analysis indicates there are three well-supported main clades of GGTs in the Ascomycota. 1) A Saccharomycotina and a Taphrinomycotinaspecific GGT sub-clade form a yeast main clade. This clade has the three relatively well-characterized fungal GGTs: (Saccharomyces cerevisiae CIS2 and Schizosaccharomyces pombe Ggt1 and Ggt2) and most of its members have all 14 of the highly conserved and critical amino acids that are found in GGTs in the other kingdoms. 2) In contrast, a main clade (GGT3) differs in 11 of the 14 highly conserved amino acids that are found in GGTs in the other kingdoms. All of the 44 Pezizomycotina analyzed have either one or two GGT3s. 3) There is a Pezizomycotina-only GGT clade that has two wellsupported sub-clades (GGT1 and GGT2); this clade differs in only two of the 14 highly conserved amino acids found in GGTs in the other kingdoms. Because the Pezizomycotina GGTs differ in apparently critical amino acids from the crosskingdom consensus, a putative GGT from Colletotrichum graminicola, a member of the Pezizomycotina, was cloned and the protein product was expressed as a secreted protein in Pichia pastoris. A GGT enzyme assay of the P. pastoris supernatant showed that the recombinant protein was active, thereby demonstrating that CgGGT1 is a bona fide GGT.
- Catabolism of 4-Hydroxybenzoic Acid by Pseudomonas sp. DJ-12
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Karegoudar, Timmanagouda B. , Chae, Jong Chan , Kim, Chi Kyung
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J. Microbiol. 1999;37(3):123-127.
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Abstract
- A Pseudomonas sp. strain DJ-12 isolated by 4-cholrobiphenyl enrichment culture technique is capable of utilizing 4-hydroxybenzoic acid as a sole source of carbon and energy. The bacterium catabolized 4-hydroxybenzoic acid through the intermediate formation of protocatechuic acid, which was further metabolized. The cell free extracts of pseudomonas sp. DJ-12, grown on 4-hydroxybenzoic acid showed higher activities of 4-hydroxyenzoate 3-hydroxylase and protocatechuate 4,5-dioxygenase, but the activity of catechol 2,3-dioxygenase was lower. The results suggest that 4-hydroxybenzoic acid is catabolized via protocatechuic acid rather than catechol or gentisic acid in this bacterium and that the protocatechuic acid formed was metabolized through a metacleavage pathway by protocatechuate 4,5-dioxygenase.