History of science – spores.

Gould, G. W.

doi:10.1111/j.1365-2672.2006.02888.x

Cited by 95 publications

(59 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unlike vegetative cells, spores are resistant to many environmental insults, including extreme pH, high temperatures, chemical treatment, radiation, desiccation, and starvation (34,43). These characteristics allow the metabolically inactive, dormant morphotype to survive outside a host for centuries (13) and hinder cleanup efforts in contaminated areas. Environmental conditions inside the B. anthracis host support the resumption of metabolic activity, triggering the spores to germinate into vegetative cells.…”

mentioning

confidence: 99%

The Bacillus anthracis SleL (YaaH) Protein Is an N -Acetylglucosaminidase Involved in Spore Cortex Depolymerization

Lambert

Popham

2008

J Bacteriol

View full text Add to dashboard Cite

Bacillus anthracis spores, the infectious agents of anthrax, are notoriously difficult to remove from contaminated areas because they are resistant to many eradication methods. These resistance properties are due to the spore's dehydration and dormancy and to the multiple protective layers surrounding the spore core, one of which is the cortex. In order for B. anthracis spores to germinate and resume growth, the cortex peptidoglycan must be depolymerized. This study reports on analyses of sleL (yaaH), which encodes a cortex-lytic enzyme. The inactivation of sleL does not affect vegetative growth, spore viability, or the initial stages of germination, including dipicolinic acid release. However, mutant spores exhibit a slight delay in the loss of optical density compared to that of wild-type spores. Mutants also retain more diaminopimelic acid and N-acetylmuramic acid during germination than wild-type spores, suggesting that the cortex peptidoglycan is not being hydrolyzed as rapidly. This finding is supported by high-pressure liquid chromatography analysis of the peptidoglycan structure used to confirm that SleL acts as an N-acetylglucosaminidase. When sleL is inactivated, the cortex peptidoglycan is not depolymerized into small muropeptides but instead is retained within the spore as large fragments. In the absence of the sleL-encoded N-acetylglucosaminidase, other cortex-lytic enzymes break down the cortex peptidoglycan sufficiently to allow rapid germination and outgrowth.

show abstract

mentioning

confidence: 99%

The Bacillus anthracis SleL (YaaH) Protein Is an N -Acetylglucosaminidase Involved in Spore Cortex Depolymerization

Lambert

Popham

2008

J Bacteriol

View full text Add to dashboard Cite

show abstract

“…These resistance properties allow spores to survive in the environment for extended periods and have made eradication from contaminated sites incredibly difficult (4). Spore dormancy and wet heat resistance are largely dependent on spore core dehydration, which is maintained by a thick layer of modified peptidoglycan (PG) known as the cortex (2,5).…”

mentioning

confidence: 99%

Role of YpeB in Cortex Hydrolysis during Germination of Bacillus anthracis Spores

Bernhards

Popham

2014

J Bacteriol

View full text Add to dashboard Cite

The infectious agent of the disease anthrax is the spore of Bacillus anthracis. Bacterial spores are extremely resistant to environmental stresses, which greatly hinders spore decontamination efforts. The spore cortex, a thick layer of modified peptidoglycan, contributes to spore dormancy and resistance by maintaining the low water content of the spore core. The cortex is degraded by germination-specific lytic enzymes (GSLEs) during spore germination, rendering the cells vulnerable to common disinfection techniques. This study investigates the relationship between SleB, a GSLE in B. anthracis, and YpeB, a protein necessary for SleB stability and function. The results indicate that ⌬sleB and ⌬ypeB spores exhibit similar germination phenotypes and that the two proteins have a strict codependency for their incorporation into the dormant spore. In the absence of its partner protein, SleB or YpeB is proteolytically degraded soon after expression during sporulation, rather than escaping the developing spore. The three PepSY domains of YpeB were examined for their roles in the interaction with SleB. YpeB truncation mutants illustrate the necessity of a region beyond the first PepSY domain for SleB stability. Furthermore, site-directed mutagenesis of highly conserved residues within the PepSY domains resulted in germination defects corresponding to reduced levels of both SleB and YpeB in the mutant spores. These results identify residues involved in the stability of both proteins and reiterate their codependent relationship. It is hoped that the study of GSLEs and interacting proteins will lead to the use of GSLEs as targets for efficient activation of spore germination and facilitation of spore cleanup. Bacterial spores from the Bacillus and Clostridium genera are metabolically dormant and are known for their extreme resistance to heat, desiccation, UV radiation, chemicals, and other insults (1-3). These resistance properties allow spores to survive in the environment for extended periods and have made eradication from contaminated sites incredibly difficult (4). Spore dormancy and wet heat resistance are largely dependent on spore core dehydration, which is maintained by a thick layer of modified peptidoglycan (PG) known as the cortex (2, 5). While vegetative cell wall PG consists of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) sugars, approximately 50% of NAM residues in the cortex are converted to muramic-␦-lactam, while an additional portion of the NAM side chains is generally cleaved to a single L-alanine (6-11).The spore form of Bacillus anthracis is the etiological agent for all types of anthrax infections: inhalational, gastrointestinal, and cutaneous anthrax, as well as the newest form described, injectional anthrax (12, 13). When the spore senses the availability of nutrients, such as when it enters a suitable host, germination is triggered, causing a chain of events that ultimately result in a vegetative cell capable of producing deadly toxins (1, 12). After germinant contact with rec...

show abstract

“…This observation was also explained in terms of a germination-based mechanism. [6,18] Pressure-induced germination Downloaded by [New York University] at 00:46 22 July 2015 was shown to be strongly temperature dependent, being virtually absent at values less than 10°C and most prominent at the 40-50°C range. [18] …”

Section: Calculation Of the Z Value At Different Pressure Valuesmentioning

confidence: 98%

“…However, low-temperature HPP remains inapplicable for sterilization in most cases. [6] Nakayama and Yano [7] found that spores of six Bacillus species were not inactivated when exposed to 980 MPa for 40 min at room temperature; however, effective inactivation was achieved at lower pressures ( ∼ 400 MPa) if the temperature exceeded 50°C. For example, Stewart et al [8] treated Bacillus subtilis spores at 404 MPa and 70°C for 15 min and achieved 5 decimal reductions in the cell count at neutral pH.…”

Section: Introductionmentioning

confidence: 99%

Moderate hydrostatic pressure–temperature combinations for inactivation ofBacillus subtilisspores

Obaidat

Aljawhiri

et al. 2015

High Pressure Research

View full text Add to dashboard Cite

2015):Moderate hydrostatic pressure-temperature combinations for inactivation of Bacillus subtilis spores, HighWe report the effect of using moderate hydrostatic pressure, 40-140 MPa, at moderate temperature (38-58°C) to inactivate Bacillus subtilis spores in McIlvaine's citric phosphate buffer at pH 6. We have investigated several parameters: pressure applied, holding time, pressure cycling, and temperature. The kinetics of spore inactivation is reported. The results show that spore inactivation is exponentially proportional to the time the sample is exposed to pressure. Spore germination and inactivation occur at the hydrostatic pressures/temperature combinations we explored. Cycling the pressure while keeping the total time at high pressure constant does not significantly increase spore inactivation. We show that temperature increases spore inactivation at two different rates; a slow rate below 33°C, and at a more rapid rate at higher temperatures. Increasing pressure leads to an increase in spore inactivation below 95 MPa; however, further increases in pressure give a similar rate kill. The time dependence of the effect of pressure is consistent with the first-order model (R 2 > 0.9). The thermal resistance values (Z T ) of B. subtilis spores are 30°C, 37°C, and 40°C at 60, 80, 100 MPa. The increase in Z T value at higher pressures indicates lower temperature sensitivity. The pressure resistance values (Z P ) are 125, 125 and 143 MPa at 38°C, 48°C, and 58°C. These Z P values are lower than those reported for B. subtilis spores in the literature, which indicates higher sensitivity at pressures less than about 140 MPa. We show that at temperatures < 60°C, B. subtilis spores are inactivated at pressures below 100 MPa. This finding could have implications for the design of the sterilization equipment.

show abstract

History of science – spores.

Cited by 95 publications

References 48 publications

The Bacillus anthracis SleL (YaaH) Protein Is an N -Acetylglucosaminidase Involved in Spore Cortex Depolymerization

The Bacillus anthracis SleL (YaaH) Protein Is an N -Acetylglucosaminidase Involved in Spore Cortex Depolymerization

Role of YpeB in Cortex Hydrolysis during Germination of Bacillus anthracis Spores

Moderate hydrostatic pressure–temperature combinations for inactivation ofBacillus subtilisspores

Contact Info

Product

Resources

About