The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Joseph A. Sorg - One of the best experts on this subject based on the ideXlab platform.
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Spore cortex hydrolysis precedes dipicolinic acid release during clostridium difficile Spore germination
Journal of Bacteriology, 2015Co-Authors: Michael B Francis, Charlotte A Allen, Joseph A. SorgAbstract:ABSTRACT Bacterial Spore germination is a process whereby a dormant Spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated Spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the Spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released during stage I. Thus, DPA release precedes cortex hydrolysis during B. subtilis Spore germination. Here, we investigated the timing of DPA release and cortex hydrolysis during Clostridium difficile Spore germination and found that cortex hydrolysis precedes DPA release. Inactivation of either the bile acid germinant receptor, cspC, or the cortex hydrolase, sleC, prevented both cortex hydrolysis and DPA release. Because both cortex hydrolysis and DPA release during C. difficile Spore germination are dependent on the presence of the germinant receptor and the cortex hydrolase, the release of DPA from the core may rely on the osmotic swelling of the core upon cortex hydrolysis. These results have implications for the hypothesized glycine receptor and suggest that the initiation of germinant receptor-mediated C. difficile Spore germination proceeds through a novel germination pathway. IMPORTANCEClostridium difficile infects antibiotic-treated hosts and spreads between hosts as a dormant Spore. In a host, Spores germinate to the vegetative form that produces the toxins necessary for disease. C. difficile Spore germination is stimulated by certain bile acids and glycine. We recently identified the bile acid germinant receptor as the germination-specific, protease-like CspC. CspC is likely cortex localized, where it can transmit the bile acid signal to the cortex hydrolase, SleC. Due to the differences in location of CspC compared to the Bacillus subtilis germinant receptors, we hypothesized that there are fundamental differences in the germination processes between the model organism and C. difficile. We found that C. difficile Spore germination proceeds through a novel pathway.
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Spore cortex hydrolysis precedes dipicolinic acid release during clostridium difficile Spore germination
Journal of Bacteriology, 2015Co-Authors: Michael B Francis, Charlotte A Allen, Joseph A. SorgAbstract:ABSTRACT Bacterial Spore germination is a process whereby a dormant Spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated Spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the Spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released during stage I. Thus, DPA release precedes cortex hydrolysis during B. subtilis Spore germination. Here, we investigated the timing of DPA release and cortex hydrolysis during Clostridium difficile Spore germination and found that cortex hydrolysis precedes DPA release. Inactivation of either the bile acid germinant receptor, cspC, or the cortex hydrolase, sleC, prevented both cortex hydrolysis and DPA release. Because both cortex hydrolysis and DPA release during C. difficile Spore germination are dependent on the presence of the germinant receptor and the cortex hydrolase, the release of DPA from the core may rely on the osmotic swelling of the core upon cortex hydrolysis. These results have implications for the hypothesized glycine receptor and suggest that the initiation of germinant receptor-mediated C. difficile Spore germination proceeds through a novel germination pathway. IMPORTANCEClostridium difficile infects antibiotic-treated hosts and spreads between hosts as a dormant Spore. In a host, Spores germinate to the vegetative form that produces the toxins necessary for disease. C. difficile Spore germination is stimulated by certain bile acids and glycine. We recently identified the bile acid germinant receptor as the germination-specific, protease-like CspC. CspC is likely cortex localized, where it can transmit the bile acid signal to the cortex hydrolase, SleC. Due to the differences in location of CspC compared to the Bacillus subtilis germinant receptors, we hypothesized that there are fundamental differences in the germination processes between the model organism and C. difficile. We found that C. difficile Spore germination proceeds through a novel pathway.
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Clostridium difficile Spore biology: sporulation, germination, and Spore structural proteins
Trends in Microbiology, 2014Co-Authors: Daniel Paredes-sabja, Aimee Shen, Joseph A. SorgAbstract:Clostridium difficile is a Gram-positive, Spore-forming obligate anaerobe and a major nosocomial pathogen of worldwide concern. Owing to its strict anaerobic requirements, the infectious and transmissible morphotype is the dormant Spore. In susceptible patients, C. difficile Spores germinate in the colon to form the vegetative cells that initiate Clostridium difficile infections (CDI). During CDI, C. difficile induces a sporulation pathway that produces more Spores; these Spores are responsible for the persistence of C. difficile in patients and horizontal transmission between hospitalized patients. Although important to the C. difficile lifecycle, the C. difficile Spore proteome is poorly conserved when compared to members of the Bacillus genus. Further, recent studies have revealed significant differences between C. difficile and Bacillus subtilis at the level of sporulation, germination, and Spore coat and exosporium morphogenesis. In this review, the regulation of the sporulation and germination pathways and the morphogenesis of the Spore coat and exosporium will be discussed.
Peter Setlow - One of the best experts on this subject based on the ideXlab platform.
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intracellular membranes of bacterial endoSpores are reservoirs for Spore core membrane expansion during Spore germination
Scientific Reports, 2018Co-Authors: Michael Laue, Christin Dittmann, Peter SetlowAbstract:Bacterial endoSpores are formed by certain bacteria, such as Bacillus subtilis or the pathogenic Bacillus anthracis and Clostridioides difficile, to allow survival in environmental conditions which are lethal to vegetative bacteria. The Spores possess a particular architecture and molecular inventory which endow them with a remarkable resistance against desiccation, heat and radiation. Another remarkable Spore feature is their rapid return to vegetative growth during Spore germination and outgrowth. The underlying processes of this latter physiological and morphological transformation involve a number of different events, some of which are mechanistically not entirely understood. One of these events is the expansion of the central Spore core, which contains the DNA, RNA and most Spore enzymes. To date, it has been unclear how the ~1.3- to 1.6-fold expansion of the core membrane surface area that accompanies core expansion takes place, since this occurs in the absence of significant if any ATP synthesis. In the current work, we demonstrate the presence of intracellular membrane structures in Spores located just below the core membrane. During Spore germination these internal core membranes disappear when the core size increases, suggesting that they are integrated into the core membrane to allow core expansion. These intracellular membranes are most probably present as more or less compressed vesicles or tubules within the dormant Spore core. Investigations of Spores from different species suggest that these intracellular membrane structures below the core membrane are a general feature of endoSpore forming bacteria.
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on the origin of live Spores in γ irradiated Spore preparations a perfect example of poisson distribution a careful consideration of the safety and security of inactivated Spore shipments is needed
Microbe Magazine, 2016Co-Authors: Shanmuga Sozhamannan, Peter Setlow, Michael A Smith, Philip C HannaAbstract:The recent revelation of the shipment of γ irradiation-inactivated Bacillus anthracis Spore reference materials containing a small number of live Spores (Department of Defense [DoD] Laboratory Review. DoD Launches Review of Lab Procedures Involving Anthrax. http://www.defense.gov/news/newsarticle.aspx?id=128939, May 29, 2015) has raised concerns about the safety and security of these materials and doubts on the validity of the protocols and procedures used to prepare these materials. Such inactivated Spore materials have historically fulfilled critical needs: as positive controls in assays used to detect these pathogens in suspected samples (live agents cannot be shipped and used in field settings), and are also used in improvement of currently deployed detection methods or development of new methods/platforms for detection of these agents; in other words, to develop and validate detection assays, and for quality assurance activities such as proficiency testing. The committee for comprehensive review of DoD Laboratory procedures, processes, and protocols associated with inactivating B. anthracis Spores has found inherent deficiencies in protocols in three phases in the production of inactive Spores that could lead to nonsterile products: (1) radiation dosing, (2) viability testing, and (3) aseptic operations (contamination prevention). These deficiencies and other factors contributed to the establishment of protocols that do not completely or permanently sterilize these samples (http://archive.defense.gov/home/features/2015/0615_lab-stats/docs/Review-Committee-Report-Final.pdf, July 13, 2015). The review committee made a number of recommendations, including initiating studies to understand the science of irradiating Spores and establishment of standardized protocols across the labs engaged in inactivated Spore production. In addition, a clear understanding of the nature of the surviving Spores would aid in understanding the phase(s) in which the failure occurred and fixing the problem. Here we consider a few hypotheses.
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slow leakage of ca dipicolinic acid from individual bacillus Spores during initiation of Spore germination
Journal of Bacteriology, 2015Co-Authors: Shiwei Wang, Peter SetlowAbstract:ABSTRACT When exposed to nutrient or nonnutrient germinants, individual Bacillus Spores can return to life through germination followed by outgrowth. Laser tweezers, Raman spectroscopy, and either differential interference contrast or phase-contrast microscopy were used to analyze the slow dipicolinic acid (DPA) leakage (normally ∼20% of Spore DPA) from individual Spores that takes place prior to the lag time, T lag , when Spores begin rapid release of remaining DPA. Major conclusions from this work with Bacillus subtilis Spores were as follows: (i) slow DPA leakage from wild-type Spores germinating with nutrients did not begin immediately after nutrient exposure but only at a later heterogeneous time T 1 ; (ii) the period of slow DPA leakage (Δ T leakage = T lag − T 1 ) was heterogeneous among individual Spores, although the amount of DPA released in this period was relatively constant; (iii) increases in germination temperature significantly decreased T 1 times but increased values of Δ T leakage ; (iv) upon germination with l-valine for 10 min followed by addition of d-alanine to block further germination, all germinated Spores had T 1 times of less than 10 min, suggesting that T 1 is the time when Spores become committed to germinate; (v) elevated levels of SpoVA proteins involved in DPA movement in Spore germination decreased T 1 and T lag times but not the amount of DPA released in Δ T leakage ; (vi) lack of the cortex-lytic enzyme CwlJ increased DPA leakage during germination due to longer Δ T leakage times in which more DPA was released; and (vii) there was slow DPA leakage early in germination of B. subtilis Spores by the nonnutrients CaDPA and dodecylamine and in nutrient germination of Bacillus cereus and Bacillus megaterium Spores. Overall, these findings have identified and characterized a new early event in Bacillus Spore germination.
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Spore Resistance Properties
Microbiology spectrum, 2014Co-Authors: Peter SetlowAbstract:Spores of various Bacillus and Clostridium species are among the most resistant life forms known. Since the Spores of some species are causative agents of much food spoilage, food poisoning, and human disease, and the Spores of Bacillus anthracis are a major bioweapon, there is much interest in the mechanisms of Spore resistance and how these Spores can be killed. This article will discuss the factors involved in Spore resistance to agents such as wet and dry heat, desiccation, UV and γ-radiation, enzymes that hydrolyze bacterial cell walls, and a variety of toxic chemicals, including genotoxic agents, oxidizing agents, aldehydes, acid, and alkali. These resistance factors include the outer layers of the Spore, such as the thick proteinaceous coat that detoxifies reactive chemicals; the relatively impermeable inner Spore membrane that restricts access of toxic chemicals to the Spore core containing the Spore's DNA and most enzymes; the low water content and high level of dipicolinic acid in the Spore core that protect core macromolecules from the effects of heat and desiccation; the saturation of Spore DNA with a novel group of proteins that protect the DNA against heat, genotoxic chemicals, and radiation; and the repair of radiation damage to DNA when Spores germinate and return to life. Despite their extreme resistance, Spores can be killed, including by damage to DNA, crucial Spore proteins, the Spore's inner membrane, and one or more components of the Spore germination apparatus.
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elastic and inelastic light scattering from single bacterial Spores in an optical trap allows the monitoring of Spore germination dynamics
Analytical Chemistry, 2009Co-Authors: Lixin Peng, Peter Setlow, De Chen, Yong-qing LiAbstract:Raman scattering spectroscopy and elastic light scattering intensity (ESLI) were used to simultaneously measure levels of Ca-dipicolinic acid (CaDPA) and changes in Spore morphology and refractive index during germination of individual B. subtilis Spores with and without the two redundant enzymes (CLEs), CwlJ and SleB, that degrade Spores’ peptidoglycan cortex. Conclusions from these measurements include: 1) CaDPA release from individual wild-type germinating Spores was biphasic; in a first heterogeneous slow phase, Tlag, CaDPA levels decreased ∼15% and in the second phase ending at Trelease, remaining CaDPA was released rapidly; 2) in L-alanine germination of wild-type Spores and Spores lacking SleB: a) the ESLI rose ∼2-fold shortly before Tlag at T1; b) following Tlag, the ESLI again rose ∼2-fold at T2 when CaDPA levels had decreased ∼50%; and c) the ESLI reached its maximum value at ∼Trelease and then decreased; 3) in CaDPA germination of wild-type Spores: a) Tlag increased and the first increase in ESLI occurred well before Tlag, consistent with different pathways for CaDPA and L-alanine germination; b) at Trelease the ESLI again reached its maximum value; 4) in L-alanine germination of Spores lacking both CLEs and unable to degrade their cortex, the time ΔTrelease (Trelease–Tlag) for excretion of ≥75% of CaDPA was ∼15-fold higher than that for wild-type or sleB Spores; and 5) Spores lacking only CwlJ exhibited a similar, but not identical ESLI pattern during L-alanine germination to that seen with cwlJ sleB Spores, and the high value for ΔTrelease.
Michael B Francis - One of the best experts on this subject based on the ideXlab platform.
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Spore cortex hydrolysis precedes dipicolinic acid release during clostridium difficile Spore germination
Journal of Bacteriology, 2015Co-Authors: Michael B Francis, Charlotte A Allen, Joseph A. SorgAbstract:ABSTRACT Bacterial Spore germination is a process whereby a dormant Spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated Spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the Spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released during stage I. Thus, DPA release precedes cortex hydrolysis during B. subtilis Spore germination. Here, we investigated the timing of DPA release and cortex hydrolysis during Clostridium difficile Spore germination and found that cortex hydrolysis precedes DPA release. Inactivation of either the bile acid germinant receptor, cspC, or the cortex hydrolase, sleC, prevented both cortex hydrolysis and DPA release. Because both cortex hydrolysis and DPA release during C. difficile Spore germination are dependent on the presence of the germinant receptor and the cortex hydrolase, the release of DPA from the core may rely on the osmotic swelling of the core upon cortex hydrolysis. These results have implications for the hypothesized glycine receptor and suggest that the initiation of germinant receptor-mediated C. difficile Spore germination proceeds through a novel germination pathway. IMPORTANCEClostridium difficile infects antibiotic-treated hosts and spreads between hosts as a dormant Spore. In a host, Spores germinate to the vegetative form that produces the toxins necessary for disease. C. difficile Spore germination is stimulated by certain bile acids and glycine. We recently identified the bile acid germinant receptor as the germination-specific, protease-like CspC. CspC is likely cortex localized, where it can transmit the bile acid signal to the cortex hydrolase, SleC. Due to the differences in location of CspC compared to the Bacillus subtilis germinant receptors, we hypothesized that there are fundamental differences in the germination processes between the model organism and C. difficile. We found that C. difficile Spore germination proceeds through a novel pathway.
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Spore cortex hydrolysis precedes dipicolinic acid release during clostridium difficile Spore germination
Journal of Bacteriology, 2015Co-Authors: Michael B Francis, Charlotte A Allen, Joseph A. SorgAbstract:ABSTRACT Bacterial Spore germination is a process whereby a dormant Spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated Spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the Spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released during stage I. Thus, DPA release precedes cortex hydrolysis during B. subtilis Spore germination. Here, we investigated the timing of DPA release and cortex hydrolysis during Clostridium difficile Spore germination and found that cortex hydrolysis precedes DPA release. Inactivation of either the bile acid germinant receptor, cspC, or the cortex hydrolase, sleC, prevented both cortex hydrolysis and DPA release. Because both cortex hydrolysis and DPA release during C. difficile Spore germination are dependent on the presence of the germinant receptor and the cortex hydrolase, the release of DPA from the core may rely on the osmotic swelling of the core upon cortex hydrolysis. These results have implications for the hypothesized glycine receptor and suggest that the initiation of germinant receptor-mediated C. difficile Spore germination proceeds through a novel germination pathway. IMPORTANCEClostridium difficile infects antibiotic-treated hosts and spreads between hosts as a dormant Spore. In a host, Spores germinate to the vegetative form that produces the toxins necessary for disease. C. difficile Spore germination is stimulated by certain bile acids and glycine. We recently identified the bile acid germinant receptor as the germination-specific, protease-like CspC. CspC is likely cortex localized, where it can transmit the bile acid signal to the cortex hydrolase, SleC. Due to the differences in location of CspC compared to the Bacillus subtilis germinant receptors, we hypothesized that there are fundamental differences in the germination processes between the model organism and C. difficile. We found that C. difficile Spore germination proceeds through a novel pathway.
Charlotte A Allen - One of the best experts on this subject based on the ideXlab platform.
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Spore cortex hydrolysis precedes dipicolinic acid release during clostridium difficile Spore germination
Journal of Bacteriology, 2015Co-Authors: Michael B Francis, Charlotte A Allen, Joseph A. SorgAbstract:ABSTRACT Bacterial Spore germination is a process whereby a dormant Spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated Spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the Spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released during stage I. Thus, DPA release precedes cortex hydrolysis during B. subtilis Spore germination. Here, we investigated the timing of DPA release and cortex hydrolysis during Clostridium difficile Spore germination and found that cortex hydrolysis precedes DPA release. Inactivation of either the bile acid germinant receptor, cspC, or the cortex hydrolase, sleC, prevented both cortex hydrolysis and DPA release. Because both cortex hydrolysis and DPA release during C. difficile Spore germination are dependent on the presence of the germinant receptor and the cortex hydrolase, the release of DPA from the core may rely on the osmotic swelling of the core upon cortex hydrolysis. These results have implications for the hypothesized glycine receptor and suggest that the initiation of germinant receptor-mediated C. difficile Spore germination proceeds through a novel germination pathway. IMPORTANCEClostridium difficile infects antibiotic-treated hosts and spreads between hosts as a dormant Spore. In a host, Spores germinate to the vegetative form that produces the toxins necessary for disease. C. difficile Spore germination is stimulated by certain bile acids and glycine. We recently identified the bile acid germinant receptor as the germination-specific, protease-like CspC. CspC is likely cortex localized, where it can transmit the bile acid signal to the cortex hydrolase, SleC. Due to the differences in location of CspC compared to the Bacillus subtilis germinant receptors, we hypothesized that there are fundamental differences in the germination processes between the model organism and C. difficile. We found that C. difficile Spore germination proceeds through a novel pathway.
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Spore cortex hydrolysis precedes dipicolinic acid release during clostridium difficile Spore germination
Journal of Bacteriology, 2015Co-Authors: Michael B Francis, Charlotte A Allen, Joseph A. SorgAbstract:ABSTRACT Bacterial Spore germination is a process whereby a dormant Spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated Spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the Spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released during stage I. Thus, DPA release precedes cortex hydrolysis during B. subtilis Spore germination. Here, we investigated the timing of DPA release and cortex hydrolysis during Clostridium difficile Spore germination and found that cortex hydrolysis precedes DPA release. Inactivation of either the bile acid germinant receptor, cspC, or the cortex hydrolase, sleC, prevented both cortex hydrolysis and DPA release. Because both cortex hydrolysis and DPA release during C. difficile Spore germination are dependent on the presence of the germinant receptor and the cortex hydrolase, the release of DPA from the core may rely on the osmotic swelling of the core upon cortex hydrolysis. These results have implications for the hypothesized glycine receptor and suggest that the initiation of germinant receptor-mediated C. difficile Spore germination proceeds through a novel germination pathway. IMPORTANCEClostridium difficile infects antibiotic-treated hosts and spreads between hosts as a dormant Spore. In a host, Spores germinate to the vegetative form that produces the toxins necessary for disease. C. difficile Spore germination is stimulated by certain bile acids and glycine. We recently identified the bile acid germinant receptor as the germination-specific, protease-like CspC. CspC is likely cortex localized, where it can transmit the bile acid signal to the cortex hydrolase, SleC. Due to the differences in location of CspC compared to the Bacillus subtilis germinant receptors, we hypothesized that there are fundamental differences in the germination processes between the model organism and C. difficile. We found that C. difficile Spore germination proceeds through a novel pathway.
Adam Driks - One of the best experts on this subject based on the ideXlab platform.
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morphogenesis of bacillus Spore surfaces
Journal of Bacteriology, 2003Co-Authors: Venkata G R Chada, Erik A Sanstad, Rong Wang, Adam DriksAbstract:Spores produced by bacilli are encased in a proteinaceous multilayered coat and, in some species (including Bacillus anthracis), further surrounded by a glycoprotein-containing exosporium. To characterize bacillus Spore surface morphology and to identify proteins that direct formation of coat surface features, we used atomic-force microscopy (AFM) to image the surfaces of wild-type and mutant Spores of Bacillus subtilis, as well as the Spore surfaces of Bacillus cereus 569 and the Sterne strain of Bacillus anthracis. This analysis revealed that the coat surfaces in these strains are populated by a series of bumps ranging between 7 and 40 nm in diameter, depending on the species. Furthermore, a series of ridges encircled the Spore, most of which were oriented along the long axis of the Spore. The structures of these ridges differ sufficiently between species to permit species-specific identification. We propose that ridges are formed early in Spore formation, when the Spore volume likely decreases, and that when the Spore swells during germination the ridges unfold. AFM analysis of a set of B. subtilis coat protein gene mutants revealed three coat proteins with roles in coat surface morphology: CotA, CotB, and CotE. Our data indicate novel roles for CotA and CotB in ridge pattern formation. Taken together, these results are consistent with the view that the coat is not inert. Rather, the coat is a dynamic structure that accommodates changes in Spore volume.
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Bacillus subtilis Spore Coat
Microbiology and Molecular Biology Reviews, 1999Co-Authors: Adam DriksAbstract:In response to starvation, bacilli and clostridia undergo a specialized program of development that results in the production of a highly resistant dormant cell type known as the Spore. A proteinacious shell, called the coat, encases the Spore and plays a major role in Spore survival. The coat is composed of over 25 polypeptide species, organized into several morphologically distinct layers. The mechanisms that guide coat assembly have been largely unknown until recently. We now know that proper formation of the coat relies on the genetic program that guides the synthesis of Spore components during development as well as on morphogenetic proteins dedicated to coat assembly. Over 20 structural and morphogenetic genes have been cloned. In this review, we consider the contributions of the known coat and morphogenetic proteins to coat function and assembly. We present a model that describes how morphogenetic proteins direct coat assembly to the specific subcellular site of the nascent Spore surface and how they establish the coat layers. We also discuss the importance of posttranslational processing of coat proteins in coat morphogenesis. Finally, we review some of the major outstanding questions in the field.
