The Exosporium Layer of Bacterial Spores: a Connection to the Environment and the Infected Host

Stewart, George C.

doi:10.1128/mmbr.00050-15

Cited by 138 publications

(159 citation statements)

References 198 publications

(337 reference statements)

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“…Several external bacterial spore envelope proteins are normally found in members of the order Bacillales, as shown in the studies on different Bacillus cereus group species21. Our approach led to the isolation of CHRD and ExsC homologues, but we cannot exclude that other B. laterosporus proteins from the spore coat or the exosporium, may have similar or higher importance in the pathogenic process.…”

Section: Discussionmentioning

confidence: 93%

Spore surface proteins of Brevibacillus laterosporus are involved in insect pathogenesis

Marche

Mura

Falchi

et al. 2017

Sci Rep

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Outer spore envelope proteins of pathogenic bacteria often present specific virulence factors and tools to evade the defence system of their hosts. Brevibacillus laterosporus, a pathogen of invertebrates and an antimicrobial-producing species, is characterised by a unique spore coat and canoe-shaped parasporal body (SC-CSPB) complex surrounding the core spore. In the present study, we identified and characterised major proteins of the SC-CSPB complex of B. laterosporus, and we investigated their entomopathogenic role. Employing a proteomic approach and a B. laterosporus-house fly study model, we found four highly conserved proteins (ExsC, CHRD, CpbA and CpbB) that function as insect virulence factors. CpbA was associated with a significantly higher mortality of flies and greater relative gene expression levels during sporulation, compared to the other SC-CSPB proteins. Taken together, we suggest that spore surface proteins are a part of a complex set of toxins and virulence factors that B. laterosporus employs in its pathogenicity against flies.

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Section: Discussionmentioning

confidence: 93%

Spore surface proteins of Brevibacillus laterosporus are involved in insect pathogenesis

Marche

Mura

Falchi

et al. 2017

Sci Rep

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“…BtcryϪ spores are almost twice the length of B. atrophaeus subsp. globigii spores (9) and are surrounded by an exosporium (30). This perhaps explains why they did not stay airborne as well as B. atrophaeus subsp.…”

Section: Discussionmentioning

confidence: 94%

Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

Bishop

Stapleton

2016

Appl Environ Microbiol

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Spores of an acrystalliferous derivative of Bacillus thuringiensis subsp. kurstaki, termed Btcry؊, are morphologically, aerodynamically, and structurally indistinguishable from Bacillus anthracis spores. Btcry؊ spores were dispersed in a large, openended barn together with spores of Bacillus atrophaeus subsp. globigii, a historically used surrogate for Bacillus anthracis. Spore suspensions (2 ؋ 10 12 CFU each of B. atrophaeus subsp. globigii and Btcry؊) were aerosolized in each of five spray events using a backpack misting device incorporating an air blower; a wind of 4.9 to 7.6 m s ؊1 was also flowing through the barn in the same direction. Filter air samplers were situated throughout the barn to assess the aerosol density of the spores during each release. Trays filled with a surfactant in aqueous buffer were placed on the floor near the filter samplers to assess spore deposition. Spores were also recovered from arrays of solid surfaces (concrete, aluminum, and plywood) that had been laid on the floor and set up as a wall at the end of the barn. B. atrophaeus subsp. globigii spores were found to remain airborne for significantly longer periods, and to be deposited on horizontal surfaces at lower densities, than Btcry؊ spores, particularly near the spray source. There was a 6-fold-higher deposition of Btcry؊ spores than of B. atrophaeus subsp. globigii spores on vertical surfaces relative to the surrounding airborne density. This work is relevant for selecting the best B. anthracis surrogate for the prediction of human exposure, hazard assessment, and hazard management following a malicious release of B. anthracis. IMPORTANCEThere is concern that pathogenic bacteria could be maliciously disseminated in the air to cause human infection and disruption of normal life. The threat from spore-forming organisms, such as the causative agent of anthrax, is particularly serious. In order to assess the extent of this risk, it is important to have a surrogate organism that can be used to replicate the dispersal characteristics of the threat agent accurately. This work compares the aerosol dispersal and deposition behaviors of the surrogates Btcry؊ and B. atrophaeus subsp. globigii. Btcry؊ spores remained in the air for a shorter time, and were markedly more likely to adhere to vertical surfaces, than B. atrophaeus subsp. globigii spores. Bacillus anthracis is an important bacterial agent of concern (1). It is pathogenic to humans, particularly by inhalational exposure (2). The organism's endospores manifest greater environmental persistence and higher resistance to chemical decontaminants than those of other bacteria. Understanding of the threat posed by malicious use of B. anthracis and the development of effective countermeasures require a comparable, nonpathogenic surrogate. Bacillus atrophaeus subsp. globigii has, for many decades, been a B. anthracis surrogate (3). B. atrophaeus subsp. globigii and other surrogates related to Bacillus subtilis have generated useful information regarding spore dispersal (4, 5)....

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“…The four distal genes in the operon, spsIJKL , encode the enzymes necessary for rhamnose synthesis (Plata et al ., ; Cangiano et al , ). Even though the corresponding operon, rmlACBD , has a different name in the B. cereus group, its function appears to be conserved (Stewart, ). Interestingly, the rhamnose‐producing operon is flanked by genes involved in exosporium assembly ( bclA and genes encoding putative glycosyltransferases on one side; cotO and exsY on the other side).…”

Section: Introductionmentioning

confidence: 99%

Contributions of crust proteins to spore surface properties in Bacillus subtilis

Shuster

Khemmani

Abe

et al. 2019

Molecular Microbiology

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Summary Surface properties, such as adhesion and hydrophobicity, constrain dispersal of bacterial spores in the environment. In Bacillus subtilis, these properties are influenced by the outermost layer of the spore, the crust. Previous work has shown that two clusters, cotVWXYZ and cgeAB, encode the protein components of the crust. Here, we characterize the respective roles of these genes in surface properties using Bacterial Adherence to Hydrocarbons assays, negative staining of polysaccharides by India ink and Transmission Electron Microscopy. We showed that inactivation of crust genes caused increases in spore relative hydrophobicity, disrupted the spore polysaccharide layer, and impaired crust structure and attachment to the rest of the coat. We also found that cotO, previously identified for its role in outer coat formation, is necessary for proper encasement of the spore by the crust. In parallel, we conducted fluorescence microscopy experiments to determine the full network of genetic dependencies for subcellular localization of crust proteins. We determined that CotZ is required for the localization of most crust proteins, while CgeA is at the bottom of the genetic interaction hierarchy.

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The Exosporium Layer of Bacterial Spores: a Connection to the Environment and the Infected Host

Cited by 138 publications

References 198 publications

Spore surface proteins of Brevibacillus laterosporus are involved in insect pathogenesis

Spore surface proteins of Brevibacillus laterosporus are involved in insect pathogenesis

Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

Contributions of crust proteins to spore surface properties in Bacillus subtilis

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