Molecular Kinetics of Reviving Bacterial Spores

Segev, Einat; Rosenberg, Alex; Mamou, Gideon; Sinai, Lior; Ben-Yehuda, Sigal

doi:10.1128/jb.00093-13

Cited by 29 publications

(41 citation statements)

References 44 publications

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“…These defects did not dramatically impact the growth of this strain under nutrientrich conditions; however, in minimal medium, growth of this strain was severely attenuated compared with that of the wild type. This suggests that for Streptomyces species growing in a nutrientpoor soil environment, the lack of Rpf enzymes may confer a profound fitness cost, analogous to that seen for other bacteria (37).…”

Section: Discussionmentioning

confidence: 96%

Resuscitation-Promoting Factors Are Cell Wall-Lytic Enzymes with Important Roles in the Germination and Growth of Streptomyces coelicolor

et al. 2015

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Dormancy is a common strategy adopted by bacterial cells as a means of surviving adverse environmental conditions. For Streptomyces bacteria, this involves developing chains of dormant exospores that extend away from the colony surface. Both spore formation and subsequent spore germination are tightly controlled processes, and while significant progress has been made in understanding the underlying regulatory and enzymatic bases for these, there are still significant gaps in our understanding. One class of proteins with a potential role in spore-associated processes are the so-called resuscitation-promoting factors, or Rpfs, which in other actinobacteria are needed to restore active growth to dormant cell populations. The model species Streptomyces coelicolor encodes five Rpf proteins (RpfA to RfpE), and here we show that these proteins have overlapping functions during growth. Collectively, the S. coelicolor Rpfs promote spore germination and are critical for growth under nutrient-limiting conditions. Previous studies have revealed structural similarities between the Rpf domain and lysozyme, and our in vitro biochemical assays revealed various levels of peptidoglycan cleavage capabilities for each of these five Streptomyces enzymes. Peptidoglycan remodeling by enzymes such as these must be stringently governed so as to retain the structural integrity of the cell wall. Our results suggest that one of the Rpfs, RpfB, is subject to a unique mode of enzymatic autoregulation, mediated by a domain of previously unknown function (DUF348) located within the N terminus of the protein; removal of this domain led to significantly enhanced peptidoglycan cleavage. Streptomyces species are Gram-positive bacteria that abound in soil environments. They are renowned for their secondary metabolic capabilities; they produce a multitude of compounds that have found utility in both medicine and agriculture, including a vast array of antibiotics, chemotherapeutics, immunosuppressants, and antiparasitic agents (1). They are also well known for their complex, multicellular developmental cycle (2). The Streptomyces life cycle can be broadly divided into two stages: vegetative growth and reproductive development. Unlike most bacteria, Streptomyces organisms are filamentous, and during the vegetative phase of their life cycle, they grow by hyphal tip extension and branching, ultimately forming an interwoven network of cells known as the vegetative mycelium (3). Under certain as yet poorly defined stress conditions, vegetative growth ceases, and reproductive growth ensues. Here, unbranched filamentous cells, termed aerial hyphae, grow away from the vegetative mycelium and extend into the air. These cells then undergo a synchronous round of chromosome segregation, cell division, and cell wall modification to yield chains of dormant exospores (4). These spores are resistant to a wide variety of environmental insults and can be widely dispersed.A dormant cell state is not unique to the streptomycetes, and indeed many well-studied bacteria (e...

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Section: Discussionmentioning

confidence: 96%

Resuscitation-Promoting Factors Are Cell Wall-Lytic Enzymes with Important Roles in the Germination and Growth of Streptomyces coelicolor

et al. 2015

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“…pBADGSEI-mGFP, which expresses EI fused to monomeric GFP, was constructed by replacing the mCherry-encoding sequence with mGFP as follows: mGFP, which carries an A206K substitution in the GFPmut2 sequence, was amplified by PCR from plasmid pAR100 (73) using forward and reverse primers that introduced SacI and XbaI sites, respectively; the amplified DNA was ligated to the pBADLLEI-mCherry plasmid, which was digested with SacI and XbaI. Construction of pGSDivIVA-GFP, which encodes DivIVA fused with GFP, was carried out in two steps.…”

Section: Methodsmentioning

confidence: 99%

The General Phosphotransferase System Proteins Localize to Sites of Strong Negative Curvature in Bacterial Cells

Govindarajan

Elisha

Nevo‐Dinur

et al. 2013

mBio

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The bacterial cell poles are emerging as subdomains where many cellular activities take place, but the mechanisms for polar localization are just beginning to unravel. The general phosphotransferase system (PTS) proteins, enzyme I (EI) and HPr, which control preferential use of carbon sources in bacteria, were recently shown to localize near the Escherichia coli cell poles. Here, we show that EI localization does not depend on known polar constituents, such as anionic lipids or the chemotaxis receptors, and on the cell division machinery, nor can it be explained by nucleoid occlusion or localized translation. Detection of the general PTS proteins at the budding sites of endocytotic-like membrane invaginations in spherical cells and their colocalization with the negative curvature sensor protein DivIVA suggest that geometric cues underlie localization of the PTS system. Notably, the kinetics of glucose uptake by spherical and rod-shaped E. coli cells are comparable, implying that negatively curved “pole-like” sites support not only the localization but also the proper functioning of the PTS system in cells with different shapes. Consistent with the curvature-mediated localization model, we observed the EI protein from Bacillus subtilis at strongly curved sites in both B. subtilis and E. coli. Taken together, we propose that changes in cell architecture correlate with dynamic survival strategies that localize central metabolic systems like the PTS to subcellular domains where they remain active, thus maintaining cell viability and metabolic alertness.

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“…As a result of the latter changes, upon completion of stage II of germination, the core water content has risen to ϳ80% of wet weight, equal to that in growing cells. This increased core water content allows metabolism in the core to begin, followed by macromolecular synthesis, ultimately converting the germinated spore into a growing cell in the process of outgrowth, although there are likely several distinct periods during outgrowth (7,28).…”

Section: Overview Of Spore Germinationmentioning

confidence: 99%

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

2014

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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...

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Molecular Kinetics of Reviving Bacterial Spores

Cited by 29 publications

References 44 publications

Resuscitation-Promoting Factors Are Cell Wall-Lytic Enzymes with Important Roles in the Germination and Growth of Streptomyces coelicolor

Resuscitation-Promoting Factors Are Cell Wall-Lytic Enzymes with Important Roles in the Germination and Growth of Streptomyces coelicolor

The General Phosphotransferase System Proteins Localize to Sites of Strong Negative Curvature in Bacterial Cells

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

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