Mutational Analysis of Cell Wall Biosynthesis in<i>Mycobacterium avium</i>

Laurent, Jean‐Pierre; Hauge, Kirsten; Burnside, Kellie; Cangelosi, Gerard A.

doi:10.1128/jb.185.16.5003-5006.2003

Cited by 21 publications

(31 citation statements)

References 22 publications

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“…Similar to Mu transpososome mutagenesis of Grampositive staphylococci and streptococci (this study), Tn5 transpososomes have been used to directly mutagenize Gram-positive corynebacteria, mycobacteria and rhodococci (Derbyshire et al, 2000;Fernandes et al, 2001;Laurent et al, 2003;Oram et al, 2002;Takayama et al, 2003;Tanaka et al, 2002). In most cases, the reported genomic integration efficiencies were similar to those obtained in our study, and in some cases they were even higher.…”

Section: Discussionsupporting

confidence: 64%

Generation of transposon insertion mutant libraries for Gram-positive bacteria by electroporation of phage Mu DNA transposition complexes

et al. 2005

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Section: Discussionsupporting

confidence: 64%

Generation of transposon insertion mutant libraries for Gram-positive bacteria by electroporation of phage Mu DNA transposition complexes

et al. 2005

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“…It has 5,990 amino acids, about equal in size to the combined PstA (2,552 amino acids) and PstB (3,445 amino acids) proteins of M. avium subspecies hominissuis. In silico analysis of functional modules suggested that PstA plus PstB of M. avium subspecies hominissuis and Mps of M. smegmatis perform similar functions and differ from each other mainly by virtue of their separation into two adjacent genes in some MAC strains (15). The pstAB locus mutagenized in this study is the same one that was mutationally correlated with biofilm formation by M. avium subspecies hominissuis strain A5 (27).…”

Section: Resultsmentioning

confidence: 68%

“…The WO colony type is associated with increased virulence and multidrug resistance relative to opaque colonies that stain red (RO) on Congo red agar (4,19). Mutants with altered colony morphology were isolated and characterized (5,15,21).…”

Section: Resultsmentioning

confidence: 99%

Roles for Cell Wall Glycopeptidolipid in Surface Adherence and Planktonic Dispersal of Mycobacterium avium

Freeman

Geier

Weigel

et al. 2006

Appl Environ Microbiol

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The opportunistic pathogen Mycobacterium avium is a significant inhabitant of biofilms in drinking water distribution systems. M. avium expresses on its cell surface serovar-specific glycopeptidolipids (ssGPLs). Studies have implicated the core GPL in biofilm formation by M. avium and by other Mycobacterium species. In order to test this hypothesis in a directed fashion, three model systems were used to examine biofilm formation by mutants of M. avium with transposon insertions into pstAB (also known as nrp and mps). pstAB encodes the nonribosomal peptide synthetase that catalyzes the synthesis of the core GPL. The mutants did not adhere to polyvinyl chloride plates; however, they adhered well to plastic and glass chamber slide surfaces, albeit with different morphologies from the parent strain. In a model that quantified surface adherence under recirculating water, wild-type and pstAB mutant cells accumulated on stainless steel surfaces in equal numbers. Unexpectedly, pstAB mutant cells were >10-fold less abundant in the recirculating-water phase than parent strain cells. These observations show that GPLs are directly or indirectly required for colonization of some, but by no means all, surfaces. Under some conditions, GPLs may play an entirely different role by facilitating the survival or dispersal of nonadherent M. avium cells in circulating water. Such a function could contribute to waterborne M. avium infection.Members of the Mycobacterium avium complex (MAC), a group of closely related species and subspecies, are commonly isolated from water, food, soil, plants, and other samples. MAC species are associated with disease in birds and mammals, and some cause disease in susceptible humans. Sources of exposure include drinking water, spas, and soil. Mycobacteria are significant inhabitants of biofilms in these environments. They have been found in biofilm samples taken from water distribution systems, dental units, and medical devices at frequencies ranging from 69% to 95% of samples tested (1,11,12,25). Among the largest studies of mycobacteria in biofilms was that of Falkinham et al. (11). They sampled biofilms from posttreatment water pipes and customer water meters in eight U.S. cities. Mycobacteria were recovered from 69% of the samples and 100% of the sites. Slow-growing mycobacteria accounted for Ͼ90% of biofilm isolates. MAC species were the most common group recovered, accounting for 135 of the 267 (51%) individual Mycobacterium isolates from biofilm samples. In laboratory experiments, biofilm formation by MAC species has been correlated with chlorine resistance (24) and enhanced bronchial epithelial cell invasion (26). Despite its potential significance for human health, little is known about biofilm formation by the MAC.The cell walls of some Mycobacterium species have glycopeptidolipids (GPLs) that share a lipotetrapeptide core consisting of fatty acyl-NH-D-phenylalanine-D-allothreonine-D-alanine-L-alaninol (7). The alaninyl C terminus is rhamnosylated, and the allothreonine residue is linked to a...

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“…The phenotypes of these strains were also investigated on Congo red agar plates. Congo red is a vital dye that binds to lipoproteins or lipids present on the mycobacterial surface (39) and is used to characterize modifications affecting the cell wall (11,22,29 (Fig. 3B).…”

Section: Resultsmentioning

confidence: 99%

A Glycosyltransferase Involved in Biosynthesis of Triglycosylated Glycopeptidolipids inMycobacterium smegmatis: Impact on Surface Properties

et al. 2005

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The cell envelope of mycobacteria is a complex structure that plays an important role in the interactions of the cell with its environment and in the protection against the antimicrobial activity of the immune system. Glycopeptidolipids (GPLs) are species-or type species-specific glycolipids that are present at the surface of a number of mycobacteria and that are characterized by a high variability in glycosylation patterns. These GPLs possess various biological activities that depend mostly on the sugars capping the core molecule. In Mycobacterium smegmatis, the GPL core can be substituted by either two or three deoxyhexoses. In this study, we show that Gtf3 is a glycosyltransferase responsible for the synthesis of the triglycosylated GPLs. Biochemical analysis of these molecules, with a combination of mass spectrometry and chemical degradation methods, has shown that they contain three deoxyhexose moieties. The presence of the triglycosylated GPLs is associated with cell surface modifications that lead to a decrease in sliding motility as well as a modification in cellular aggregation and colony appearance on Congo red. Phylogenetic analysis indicated that Gtf3 is a member of a yet-uncharacterized glycosyltransferase family conserved among the mycobacteria.The mycobacterial envelope confers to mycobacteria a high impermeability to chemical disinfectants and to some antibiotics and contributes also, in the case of the pathogenic species, to the ability to survive in macrophages. This envelope is composed of a plasma membrane surrounded by a complex cell wall, which in turn is covered by a superficial layer, also called a capsule in the case of pathogenic species. The cell wall consists of a monolayer of mycoloyl residues covalently linked to the peptidoglycan-arabinogalactan complex and includes other lipids which are probably arranged to form a bilayer with the mycoloyl residues. The outermost structure, composed of proteins, carbohydrates, and (to a lesser extent) lipids, represents a privileged interface between bacilli and their environment. Both the outer lipid layer of the cell wall and the outermost capsule contain species-specific glycolipids or phospholipids (8,12,16). Glycopeptidolipids (GPLs) are the predominant glycolipids in members of the Mycobacterium avium complex, a group of subspecies involved in zoonotic infection and in the infection of immunocompromised patients. GPLs are also present at the surface of M. smegmatis, a saprophytic species (17). Purified GPLs are able to disturb macrophage membrane ultrastructure (42) and to insert into phospholipid monolayers (47) or to inhibit nonopsonic phagocytosis of mycobacteria by human macrophages (48), thus suggesting a potential role in the virulence of mycobacteria. It has been shown that GPLs can decrease the phosphorylation efficiency of isolated mitochondria without modifying the active respiration (30). GPLs also play a role in sliding motility and in biofilm formation (33), probably through the interaction between the support and the bacterial...

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Mutational Analysis of Cell Wall Biosynthesis inMycobacterium avium

Cited by 21 publications

References 22 publications

Generation of transposon insertion mutant libraries for Gram-positive bacteria by electroporation of phage Mu DNA transposition complexes

Generation of transposon insertion mutant libraries for Gram-positive bacteria by electroporation of phage Mu DNA transposition complexes

Roles for Cell Wall Glycopeptidolipid in Surface Adherence and Planktonic Dispersal of Mycobacterium avium

A Glycosyltransferase Involved in Biosynthesis of Triglycosylated Glycopeptidolipids inMycobacterium smegmatis: Impact on Surface Properties

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