The physical state of water in bacterial spores

Sunde, Erik Persson; Setlow, Peter; Hederstedt, Lars; Halle, Bertil

doi:10.1073/pnas.0908712106

Cited by 151 publications

(165 citation statements)

References 57 publications

Supporting

Mentioning

155

Contrasting

Order By: Relevance

“…The major question about their degradation, however, is whether this is enzymatic or nonenzymatic, especially given the lability of RNA. It is possible that enzymes work very slowly even at the extremely low spore core water content in the spore core, perhaps with minimal levels of free water (38)(39)(40). Indeed, there are multiple RNases that participate in rRNA degradation in bacteria, in particular under starvation conditions (41,42).…”

Section: Discussionmentioning

confidence: 99%

Changes in Bacillus Spore Small Molecules, rRNA, Germination, and Outgrowth after Extended Sublethal Exposure to Various Temperatures: Evidence that Protein Synthesis Is Not Essential for Spore Germination

et al. 2016

Self Cite

View full text Add to dashboard Cite

ABSTRACTrRNAs of dormant spores of Bacillus subtilis were >95% degraded during extended incubation at 50°C, as reported previously (E. Segev, Y. Smith, and S. Ben-Yehuda, Cell 148:139 -114, 2012, doi:http://dx.doi.org/10.1016/j.cell.2011.11.059), and this was also true of spores of Bacillus megaterium. Incubation of spores of these two species for ϳ20 h at 75 to 80°C also resulted in the degradation of all or the great majority of the 23S and 16S rRNAs, although this rRNA degradation was slower than nonenzymatic hydrolysis of purified rRNAs at these temperatures. This rRNA degradation at high temperature generated almost exclusively oligonucleotides with minimal levels of mononucleotides. RNase Y, suggested to be involved in rRNA hydrolysis during B. subtilis spore incubation at 50°C, did not play a role in B. subtilis spore rRNA breakdown at 80°C. Twenty hours of incubation of Bacillus spores at 70°C also decreased the already minimal levels of ATP in dormant spores 10-to 30-fold, to <0.01% of the total free adenine nucleotide levels. Spores depleted of rRNA were viable and germinated relatively normally, often even faster than starting spores. Their return to vegetative growth was also similar to that of untreated spores for B. megaterium spores and slower for heat-treated B. subtilis spores; accumulation of rRNA took place only after completion of spore germination. These findings thus strongly suggest that protein synthesis is not essential for Bacillus spore germination. Spores of Bacillus species formed in sporulation are metabolically dormant and extremely resistant to many severe treatments, including heat, radiation, and toxic chemicals (1-3). Although these spores can survive in this dormant resistant state for many years, if given the appropriate stimulus, generally small molecules that are found in environments that are appropriate for the growth of these bacteria, the spores can rapidly break dormancy in the process of spore germination and then outgrowth (1, 4, 5). Notably, spores' extreme resistance properties are lost in the process of germination and early outgrowth, and thus, germinated spores are much easier to kill than dormant spores. This property has significant applied implications, as dormant spores are the vectors for much food spoilage, as well as some foodborne and other human diseases. Consequently, there is significant interest in mechanisms that determine rates of spore germination and how sporulation conditions, as well as storage conditions, modify spores' resistance properties and their rates of germination.In addition to the applied interest in spore resistance and germination, there has also long been much basic interest in the mechanism of spore germination, in particular, the signal transduction pathways operating during the process (4, 5). The major proteins involved in Bacillus spore germination are as follows. (i) Germinant receptors (GRs) in spores' inner membrane (IM) recognize and respond to the physiological germinants specific for spores of each species/strain. (ii)...

show abstract

Section: Discussionmentioning

confidence: 99%

Changes in Bacillus Spore Small Molecules, rRNA, Germination, and Outgrowth after Extended Sublethal Exposure to Various Temperatures: Evidence that Protein Synthesis Is Not Essential for Spore Germination

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…As noted above, the IM has some quite different properties than the plasma membrane of growing cells or fully germinated spores, in that the IM appears to be in a gel or semisolid state (17,26,(30)(31)(32). These novel IM properties are lost upon completion of spore germination, when the volume of the IM-encompassed spore core increases 1.5-to 2-fold in the absence of ATP synthesis (30).…”

Section: Major Unanswered Questions About Spore Germination By Nutrientsmentioning

confidence: 99%

“…However, the IM appears to be in a gel or semisolid state, as indicated by its passive low permeability even to water, its high viscosity, and the immobility of lipid probes in this membrane (17,26,(30)(31)(32). The fact that so many of the germination proteins act in the IM, a membrane that has rather novel properties, makes the understanding of the structure of and protein action in this membrane important.…”

Section: Overview Of Spore Germinationmentioning

confidence: 99%

Germination of Spores of Bacillus Species: What We Know and Do Not Know

2014

Self Cite

View full text Add to dashboard Cite

Spores of Bacillus species can remain in their dormant and resistant states for years, but exposure to agents such as specific nutrients can cause spores' return to life within minutes in the process of germination. This process requires a number of sporespecific proteins, most of which are in or associated with the inner spore membrane (IM). These proteins include the (i) germinant receptors (GRs) that respond to nutrient germinants, (ii) GerD protein, which is essential for GR-dependent germination, (iii) SpoVA proteins that form a channel in spores' IM through which the spore core's huge depot of dipicolinic acid is released during germination, and (iv) cortex-lytic enzymes (CLEs) that degrade the large peptidoglycan cortex layer, allowing the spore core to take up much water and swell, thus completing spore germination. While much has been learned about nutrient germination, major questions remain unanswered, including the following. T he germination of the dormant and highly resistant spores formed by members of the Firmicutes phylum, in particular bacilli and clostridia, has long been of significant research interest for four major reasons, as follows: (i) fascinating regulatory systems allow such spores to remain in their dormant, resistant state for years and yet return to active growth in minutes; (ii) while spores of most Firmicutes do not cause disease, spores of some bacilli and clostridia cause food spoilage and food-borne disease, as well as human diseases like gas gangrene, tetanus, botulism, anthrax, and pseudomembranous colitis; (iii) spores of Bacillus anthracis are a major bioterrorism threat; and (iv) spores of Clostridium difficile are an emerging public health threat (1-3). Invariably, it is the germination of spores of these organisms that leads to disease or food spoilage, and yet, when spores germinate and lose their dormancy, they lose their extreme resistance properties and become relatively easy to kill. Germination is thus both an essential part of disease pathogenesis or food spoilage and a major weak spot in these organisms' life cycle. Consequently, there has long been applied interest in spore germination, with researchers seeking to understand this process better in order to either prevent spore germination or accelerate it and then kill the newly sensitive germinated spores. This review will concentrate on the germination of spores of bacilli, primarily because of the large amount of detailed knowledge of the germination of spores of these species compared to that of spores of clostridia. However, some of the differences and similarities between the germination of spores of these related genera will also be presented. Most discussion will focus on the germination of the model sporeformer, Bacillus subtilis, although the mechanisms of germination of B. subtilis spores appear to be similar for spores of other bacilli. The properties of the various proteins that are specifically involved in the germination process will not be discussed in great detail, since these have recently be...

show abstract

“…13 Interestingly, the report of Cano and Borucki in 1995 was published shortly after the science ction movie Jurassic Park (1993), which is based on the Novel by Michael Crichton. 14 Heat resistance may also be increased due to rotationally immobilized proteins in the core [283].…”

Section: Deinococcus Radioduransmentioning

confidence: 99%

“…For instance, comparing quantitative three-dimensional density maps of the endospores in a dry and fully hydrated state may further elucidate their water content which is important for their heat resistance [283]. Endospores may also be candidates for observing time snapshots of dynamical processes such as hydration or germination [230,232] which are di cult to observe otherwise.…”

Section: ± 20mentioning

confidence: 99%

Coherent X-ray diffractive imaging on the single-cell-level of microbial samples

Wilke

2015

Göttingen Series in X-Ray Physics

View full text Add to dashboard Cite

The physical state of water in bacterial spores

Cited by 151 publications

References 57 publications

Changes in Bacillus Spore Small Molecules, rRNA, Germination, and Outgrowth after Extended Sublethal Exposure to Various Temperatures: Evidence that Protein Synthesis Is Not Essential for Spore Germination

Changes in Bacillus Spore Small Molecules, rRNA, Germination, and Outgrowth after Extended Sublethal Exposure to Various Temperatures: Evidence that Protein Synthesis Is Not Essential for Spore Germination

Germination of Spores of Bacillus Species: What We Know and Do Not Know

Coherent X-ray diffractive imaging on the single-cell-level of microbial samples

Contact Info

Product

Resources

About