Role of Outer Coat in Resistance of Bacillus megaterium Spore

Nishihara, Tsutomu; Takubo, Yoshihiro; Kawamata, Etsako; Koshikawa, Tomihiko; Ogaki, Junji; Kondo, Masaomi

doi:10.1093/oxfordjournals.jbchem.a122843

Cited by 18 publications

(15 citation statements)

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“…Permeability of the exosporium is not totally surprising since germinants present in the environment have to cross the external layers of the spore to reach their receptors, albeit germinants are typically small molecules with molecular masses typically <200 Da. Additionally, the mRFP data are broadly in agreement with the results of previous studies conducted with labeled dextrans and related molecules (Koshikawa et al, 1984; Nishihara et al, 1989). In those studies, the B. megaterium QM B1551 exosporium was suggested to represent a permeability barrier to molecules with molecular weights greater than 100 KDa, while influencing the passage of molecules with masses somewhere between 2 and 40 kDa (Koshikawa et al, 1984; Nishihara et al, 1989).…”

Section: Discussionsupporting

confidence: 90%

The Exosporium of Bacillus megaterium QM B1551 Is Permeable to the Red Fluorescence Protein of the Coral Discosoma sp.

et al. 2016

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Bacterial spores spontaneously interact and tightly bind heterologous proteins. A variety of antigens and enzymes have been efficiently displayed on spores of Bacillus subtilis, the model system for spore formers. Adsorption on B. subtilis spores has then been proposed as a non-recombinant approach for the development of mucosal vaccine/drug delivery vehicles, biocatalysts, bioremediation, and diagnostic tools. We used spores of B. megaterium QM B1551 to evaluate their efficiency as an adsorption platform. Spores of B. megaterium are significantly larger than those of B. subtilis and of other Bacillus species and are surrounded by the exosporium, an outermost surface layer present only in some Bacillus species and lacking in B. subtilis. Strain QM B1551 of B. megaterium and a derivative strain totally lacking the exosporium were used to localize the adsorbed monomeric Red Fluorescent Protein (mRFP) of the coral Discosoma sp., used as a model heterologous protein. Our results indicate that spores of B. megaterium adsorb mRFP more efficiently than B. subtilis spores, that the exosporium is essential for mRFP adsorption, and that most of the adsorbed mRFP molecules are not exposed on the spore surface but rather localized in the space between the outer coat and the exosporium.

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Section: Discussionsupporting

confidence: 90%

The Exosporium of Bacillus megaterium QM B1551 Is Permeable to the Red Fluorescence Protein of the Coral Discosoma sp.

et al. 2016

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“…Because our first experiments had shown that TBO appeared to bind to B. cereus spores, we washed the spores after phenothiazinium dye incubation and resuspended them in PBS before PDI. Figure 3 shows that there are three broad levels of effective- (33,35). Again, these experiments were carried out with a wash after incubation.…”

Section: Resultsmentioning

confidence: 99%

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Demidova

Hamblin

2005

Appl Environ Microbiol

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Spore formation is a sophisticated mechanism by which some bacteria survive conditions of stress and starvation by producing a multilayered protective capsule enclosing their condensed DNA. Spores are highly resistant to damage by heat, radiation, and commonly employed antibacterial agents. Previously, spores have also been shown to be resistant to photodynamic inactivation using dyes and light that easily destroy the corresponding vegetative bacteria. We have discovered that Bacillus spores are susceptible to photoinactivation by phenothiazinium dyes and low doses of red light. Dimethylmethylene blue, methylene blue, new methylene blue, and toluidine blue O are all effective, while alternative photosensitizers such as Rose Bengal, polylysine chlorin(e6) conjugate, a tricationic porphyrin, and a benzoporphyrin derivative, which easily kill vegetative cells, are ineffective. Spores of Bacillus cereus and B. thuringiensis are most susceptible, B. subtilis and B. atrophaeus are also killed, and B. megaterium is resistant. Photoinactivation is most effective when excess dye is washed from the spores, showing that the dye binds to the spores and that excess dye in solution can quench light delivery. The relatively mild conditions needed for spore killing could have applications for treating wounds contaminated by anthrax spores, for which conventional sporicides would have unacceptable tissue toxicity.

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“…The function of the exosporium is unknown, but it does not appear to be important either for dormancy or germination (33). It may act as a sieving barrier, preventing exoenzymic attack on the spore coat and cortex layers (83).…”

Section: The Exosporiummentioning

confidence: 99%

Anthrax

Mock

Fouet

2001

Annu. Rev. Microbiol.

929

952

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Bacillus anthracis was shown to be the etiological agent of anthrax by R. Koch and L. Pasteur at the end of the nineteenth century. The concepts on which medical microbiology are based arose from their work on this bacterium. The link between plasmids and major virulence factors of B. anthracis was not discovered until the 1980s. The three toxin components are organized in two A-B type toxins, and the bacilli are covered by an antiphagocytic polyglutamic capsule. Structure-function analysis of the toxins indicated that the common B-domain binds to a ubiquitous cell receptor and forms a heptamer after proteolytic activation. One enzyme moiety is an adenylate cyclase and the other is a Zn(2+) metalloprotease, which is able to cleave MAPKKs. The capsule covers an S-layer sequentially composed of two distinct proteins. Knowledge of the toxins facilitates the design of safer veterinary vaccines. Spore-structure analysis could contribute to the improvement of human nonliving vaccines. The phylogeny of B. anthracis within the Bacillus cereus group is also reviewed.

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Role of Outer Coat in Resistance of Bacillus megaterium Spore

Cited by 18 publications

References 0 publications

The Exosporium of Bacillus megaterium QM B1551 Is Permeable to the Red Fluorescence Protein of the Coral Discosoma sp.

The Exosporium of Bacillus megaterium QM B1551 Is Permeable to the Red Fluorescence Protein of the Coral Discosoma sp.

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Anthrax

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