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

2008 ◽  
Vol 190 (23) ◽  
pp. 7601-7607 ◽  
Author(s):  
Emily A. Lambert ◽  
David L. Popham
Keyword(s):  
Bacillus Anthracis ◽  
Dipicolinic Acid ◽  
Diaminopimelic Acid ◽  
Lytic Enzyme ◽  
Wild Type ◽  
Lytic Enzymes ◽  
Spore Viability ◽  
Chromatography Analysis ◽  
Protective Layers ◽  
Acid Release

ABSTRACT 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.

scholarly journals Contributions of Four Cortex Lytic Enzymes to Germination of Bacillus anthracis Spores

2009 ◽  
Vol 192 (3) ◽  
pp. 763-770 ◽  
Author(s):  
Jared D. Heffron ◽  
Emily A. Lambert ◽  
Nora Sherry ◽  
David L. Popham
Keyword(s):  
Bacillus Anthracis ◽  
Dipicolinic Acid ◽  
Lytic Enzymes ◽  
Spore Viability ◽  
Cooperative Action ◽  
Lytic Transglycosylase ◽  
Mutant Strains ◽  
Bacillus Anthracis Spores ◽  
Quantitative Identification

ABSTRACT Bacterial spores remain dormant and highly resistant to environmental stress until they germinate. Completion of germination requires the degradation of spore cortex peptidoglycan by germination-specific lytic enzymes (GSLEs). Bacillus anthracis has four GSLEs: CwlJ1, CwlJ2, SleB, and SleL. In this study, the cooperative action of all four GSLEs in vivo was investigated by combining in-frame deletion mutations to generate all possible double, triple, and quadruple GSLE mutant strains. Analyses of mutant strains during spore germination and outgrowth combined observations of optical density loss, colony-producing ability, and quantitative identification of spore cortex fragments. The lytic transglycosylase SleB alone can facilitate enough digestion to allow full spore viability and generates a variety of small and large cortex fragments. CwlJ1 is also sufficient to allow completion of nutrient-triggered germination independently and is a major factor in Ca2+-dipicolinic acid (DPA)-triggered germination, but its enzymatic activity remains unidentified because its products are large and not readily released from the spore's integuments. CwlJ2 contributes the least to overall cortex digestion but plays a subsidiary role in Ca2+-DPA-induced germination. SleL is an N-acetylglucosaminidase that plays the major role in hydrolyzing the large products of other GSLEs into small, rapidly released muropeptides. As the roles of these enzymes in cortex degradation become clearer, they will be targets for methods to stimulate premature germination of B. anthracis spores, greatly simplifying decontamination measures.

Effect of the cortex-lytic enzyme SleC from non-food-borne Clostridium perfringens on the germination properties of SleC-lacking spores of a food poisoning isolate

2010 ◽  
Vol 56 (11) ◽  
pp. 952-958 ◽  
Author(s):  
Daniel Paredes-Sabja ◽  
Mahfuzur R. Sarker
Keyword(s):  
Clostridium Perfringens ◽  
Spore Germination ◽  
Type Strain ◽  
Wild Type Strain ◽  
Dipicolinic Acid ◽  
Food Poisoning ◽  
Lytic Enzyme ◽  
Wild Type ◽  
Lytic Enzymes ◽  
Food Borne

The hallmark of bacterial spore germination is peptidoglycan cortex hydrolysis by cortex-lytic enzymes. In spores of Clostridium perfringens wild-type strain SM101, which causes food poisoning, the sole essential cortex-lytic enzyme SleC is activated by a unique serine protease CspB. Interestingly, the non-food-borne wild-type strain F4969 encodes a significantly divergent SleC variant (SleCF4969) and 3 serine proteases (CspA, CspB, and CspC). Consequently, in this study we evaluated the functional compatibility of SleCF4969and SleCSM101by complementing the germination phenotypes of SM101ΔsleC spores with sleCF4969. Our results show that although pro-SleCF4969was processed into mature SleCF4969in the SM101ΔsleC spores, it partially restored spore germination with nutrient medium, with a mixture of l-asparagine and KCl, or with a 1:1 chelate of Ca2+and dipicolinic acid. While the amount of dipicolinic acid released was lower, the amount of hexosamine-containing material released during germination of SM101ΔsleC(sleCF4969) spores was similar to the amount released during germination of SM101 wild-type spores. The viability of SM101ΔsleC(sleCF4969) spores was 8- and 3-fold lower than that of SM101 and F4969 spores, respectively. Together, these data indicate that the peptidoglycan cortex hydrolysis machinery in the food poisoning isolate SM101 is functionally divergent than that in the non-food-borne isolate F4969.

scholarly journals Characterization of AmiBA2446, a Novel Bacteriolytic Enzyme Active against Bacillus Species

2013 ◽  
Vol 79 (19) ◽  
pp. 5899-5906 ◽  
Author(s):  
Krunal K. Mehta ◽  
Elena E. Paskaleva ◽  
Saba Azizi-Ghannad ◽  
Daniel J. Ley ◽  
Martin A. Page ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Bactericidal Activity ◽  
Enzymatic Digestion ◽  
Enzyme Concentration ◽  
Size Exclusion ◽  
Lytic Enzyme ◽  
Bacillus Species ◽  
Significant Activity ◽  
Lytic Enzymes ◽  
Content Type

ABSTRACTThere continues to be a need for developing efficient and environmentally friendly treatments forBacillus anthracis, the causative agent of anthrax. One emerging approach for inactivation of vegetativeB. anthracisis the use of bacteriophage endolysins or lytic enzymes encoded by bacterial genomes (autolysins) with highly evolved specificity toward bacterium-specific peptidoglycan cell walls. In this work, we performedin silicoanalysis of the genome ofBacillus anthracisstrain Ames, using a consensus binding domain amino acid sequence as a probe, and identified a novel lytic enzyme that we termed AmiBA2446. This enzyme exists as a homodimer, as determined by size exclusion studies. It possessesN-acetylmuramoyl-l-alanine amidase activity, as determined from liquid chromatography-mass spectrometry (LC-MS) analysis of muropeptides released due to the enzymatic digestion of peptidoglycan. Phylogenetic analysis suggested that AmiBA2446 was an autolysin of bacterial origin. We characterized the effects of enzyme concentration and phase of bacterial growth on bactericidal activity and observed close to a 5-log reduction in the viability of cells ofBacillus cereus4342, a surrogate forB. anthracis. We further tested the bactericidal activity of AmiBA2446 against variousBacillusspecies and demonstrated significant activity againstB. anthracisandB. cereusstrains. We also demonstrated activity againstB. anthracisspores after pretreatment with germinants. AmiBA2446 enzyme was also stable in solution, retaining its activity after 4 months of storage at room temperature.

scholarly journals A Polysaccharide Deacetylase Gene (pdaA) Is Required for Germination and for Production of Muramic δ-Lactam Residues in the Spore Cortex of Bacillus subtilis

2002 ◽  
Vol 184 (21) ◽  
pp. 6007-6015 ◽  
Author(s):  
Tatsuya Fukushima ◽  
Hiroki Yamamoto ◽  
Abdelmadjid Atrih ◽  
Simon J. Foster ◽  
Junichi Sekiguchi
Keyword(s):  
Bacillus Subtilis ◽  
Phase Contrast ◽  
Biosynthetic Pathway ◽  
Wild Type Strain ◽  
Dipicolinic Acid ◽  
Northern Hybridization ◽  
Predicted Amino Acid Sequence ◽  
Wild Type ◽  
Contrast Microscopy ◽  
Acid Release

ABSTRACT The predicted amino acid sequence of Bacillus subtilis yfjS (renamed pdaA) exhibits high similarity to those of several polysaccharide deacetylases. β-Galactosidase fusion experiments and results of Northern hybridization with sporulation sigma mutants indicated that the pdaA gene is transcribed by EσG RNA polymerase. pdaA-deficient spores were bright by phase-contrast microscopy, and the spores were induced to germination on the addition of l-alanine. Germination-associated spore darkening, a slow and partial decrease in absorbance, and slightly lower dipicolinic acid release compared with that by the wild-type strain were observed. In particular, the release of hexosamine-containing materials was lacking in the pdaA mutant. Muropeptide analysis indicated that the pdaA-deficient spores completely lacked muramic δ-lactam. A pdaA-gfp fusion protein constructed in strain 168 and pdaA-deficient strains indicated that the protein is localized in B. subtilis spores. The biosynthetic pathway of muramic δ-lactam is discussed.

scholarly journals Mechanisms of Induction of Germination of Bacillus subtilis Spores by High Pressure

2002 ◽  
Vol 68 (6) ◽  
pp. 3172-3175 ◽  
Author(s):  
Madan Paidhungat ◽  
Barbara Setlow ◽  
William B. Daniels ◽  
Dallas Hoover ◽  
Efstathia Papafragkou ◽  
...  
Keyword(s):  
High Pressure ◽  
Bacillus Subtilis ◽  
Spore Germination ◽  
Dipicolinic Acid ◽  
Wild Type ◽  
Lytic Enzymes

ABSTRACT Spores of Bacillus subtilis lacking all germinant receptors germinate >500-fold slower than wild-type spores in nutrients and were not induced to germinate by a pressure of 100 MPa. However, a pressure of 550 MPa induced germination of spores lacking all germinant receptors as well as of receptorless spores lacking either of the two lytic enzymes essential for cortex hydrolysis during germination. Complete germination of spores either lacking both cortex-lytic enzymes or with a cortex not attacked by these enzymes was not induced by a pressure of 550 MPa, but treatment of these mutant spores with this pressure caused the release of dipicolinic acid. These data suggest the following conclusions: (i) a pressure of 100 MPa induces spore germination by activating the germinant receptors; and (ii) a pressure of 550 MPa opens channels for release of dipicolinic acid from the spore core, which leads to the later steps in spore germination.

scholarly journals Roles of Germination-Specific Lytic Enzymes CwlJ and SleB in Bacillus anthracis

2009 ◽  
Vol 191 (7) ◽  
pp. 2237-2247 ◽  
Author(s):  
Jared D. Heffron ◽  
Benjamin Orsburn ◽  
David L. Popham
Keyword(s):  
Bacillus Anthracis ◽  
High Performance ◽  
Structural Characteristics ◽  
Wild Type ◽  
Lytic Enzymes ◽  
Spectroscopy Analysis ◽  
Lytic Transglycosylase ◽  
Spore Resistance ◽  
Sequence Similarities ◽  
Mass Spectroscopy Analysis

ABSTRACT The structural characteristics of a spore enable it to withstand stresses that typically kill a vegetative cell. Spores remain dormant until small molecule signals induce them to germinate into vegetative bacilli. Germination requires degradation of the thick cortical peptidoglycan by germination-specific lytic enzymes (GSLEs). Bacillus anthracis has four putative GSLEs, based upon sequence similarities with enzymes in other species: SleB, CwlJ1, CwlJ2, and SleL. In this study, the roles of SleB, CwlJ1, and CwlJ2 were examined. The expression levels of all three genes peak 3.5 h into sporulation. Genetic analysis revealed that, similar to other known GSLEs, none of these gene products are individually required for growth, sporulation, or triggering of germination. However, later germination events are affected in spores lacking CwlJ1 or SleB. Compared to the wild type, germinating spores without CwlJ1 suffer a delay in optical density loss and cortex peptidoglycan release. The absence of SleB also causes a delay in cortex fragment release. A double mutant lacking both SleB and CwlJ1 is completely blocked in cortex hydrolysis and progresses through outgrowth to produce colonies at a frequency 1,000-fold lower than that of the wild-type strain. A null mutation eliminating CwlJ2 has no effect on germination. High-performance liquid chromatography and mass spectroscopy analysis revealed that SleB is required for lytic transglycosylase activity. CwlJ1 also clearly participates in cortex hydrolysis, but its specific mode of action remains unclear. Understanding the lytic germination activities that naturally diminish spore resistance can lead to methods for prematurely inducing them, thus simplifying the process of treating contaminated sites.

scholarly journals Factors Affecting Variability in Time between Addition of Nutrient Germinants and Rapid Dipicolinic Acid Release during Germination of Spores of Bacillus Species

2010 ◽  
Vol 192 (14) ◽  
pp. 3608-3619 ◽  
Author(s):  
Pengfei Zhang ◽  
Will Garner ◽  
Xuan Yi ◽  
Ji Yu ◽  
Yong-qing Li ◽  
...  
Keyword(s):  
Dipicolinic Acid ◽  
Great Majority ◽  
Bacillus Species ◽  
Published Data ◽  
Laser Tweezers ◽  
Wild Type ◽  
Factors Affecting ◽  
Number Of Factors ◽  
Heat Activation ◽  
Acid Release

ABSTRACT The simultaneous nutrient germination of hundreds of individual wild-type spores of three Bacillus species and a number of Bacillus subtilis strains has been measured by two new methods, and rates of release of the great majority of the large pool of dipicolinic acid (DPA) from individual spores of B. subtilis strains has been measured by Raman spectroscopy with laser tweezers. The results from these analyses and published data have allowed a number of significant conclusions about the germination of spores of Bacillus species as follows. (i) The time needed for release of the great majority of a Bacillus spore's DPA once rapid DPA release had begun (ΔT release) during nutrient germination was independent of the concentration of nutrient germinant used, the level of the germinant receptors (GRs) that recognize nutrient germinants used and heat activation prior to germination. Values for ΔT release were generally 0.5 to 3 min at 25 to 37°C for individual wild-type spores. (ii) Despite the conclusion above, germination of individual spores in populations was very heterogeneous, with some spores in wild-type populations completing germination ≥15-fold slower than others. (iii) The major factor in the heterogeneity in germination of individual spores in populations was the highly variable lag time, T lag, between mixing spores with nutrient germinants and the beginning of ΔT release. (iv) A number of factors decrease spores' T lag values including heat activation, increased levels of GRs/spore, and higher levels of nutrient germinants. These latter factors appear to affect the level of activated GRs/spore during nutrient germination. (v) The conclusions above lead to the simple prediction that a major factor causing heterogeneity in Bacillus spore germination is the number of functional GRs in individual spores, a number that presumably varies significantly between spores in populations.

scholarly journals SleC Is Essential for Cortex Peptidoglycan Hydrolysis during Germination of Spores of the Pathogenic Bacterium Clostridium perfringens

2009 ◽  
Vol 191 (8) ◽  
pp. 2711-2720 ◽  
Author(s):  
Daniel Paredes-Sabja ◽  
Peter Setlow ◽  
Mahfuzur R. Sarker
Keyword(s):  
Clostridium Perfringens ◽  
Spore Germination ◽  
Dipicolinic Acid ◽  
Pathogenic Bacterium ◽  
Wild Type ◽  
Lytic Enzymes ◽  
Colony Forming Efficiency ◽  
Forming Efficiency ◽  
Peptidoglycan Hydrolysis

ABSTRACT Clostridial spore germination requires degradation of the spore's peptidoglycan (PG) cortex by cortex-lytic enzymes (CLEs), and two Clostridium perfringens CLEs, SleC and SleM, degrade cortex PG in vitro. We now find that only SleC is essential for cortex hydrolysis and viability of C. perfringens spores. C. perfringens sleC spores did not germinate completely with nutrients, KCl, or a 1:1 chelate of Ca2+ and dipicolinic acid (Ca-DPA), and the colony-forming efficiency of sleC spores was 103-fold lower than that of wild-type spores. However, sleC spores incubated with various germinants released most of their DPA, although slower than wild-type or sleM spores, and DPA release from sleC sleM spores was very slow. In contrast, germination and viability of sleM spores were similar to that of wild-type spores, although sleC sleM spores had 105-fold-lower viability. These results allow the following conclusions about C. perfringens spore germination: (i) SleC is essential for cortex hydrolysis; (ii) although SleM can degrade cortex PG in vitro, this enzyme is not essential; (iii) action of SleC alone or with SleM can accelerate DPA release; and (iv) Ca-DPA does not trigger spore germination by activation of CLEs.

scholarly journals The Products of the spoVA Operon Are Involved in Dipicolinic Acid Uptake into Developing Spores of Bacillus subtilis

2002 ◽  
Vol 184 (2) ◽  
pp. 584-587 ◽  
Author(s):  
Federico Tovar-Rojo ◽  
Monica Chander ◽  
Barbara Setlow ◽  
Peter Setlow
Keyword(s):  
Bacillus Subtilis ◽  
Heat Resistance ◽  
Dipicolinic Acid ◽  
Lytic Enzyme ◽  
Acid Uptake ◽  
Wild Type ◽  
Wet Heat

ABSTRACT Bacillus subtilis cells with mutations in the spoVA operon do not complete sporulation. However, a spoVA strain with mutations that remove all three of the spore’s functional nutrient germinant receptors (termed the ger3 mutations) or the cortex lytic enzyme SleB (but not CwlJ) did complete sporulation. ger3 spoVA and sleB spoVA spores lack dipicolinic acid (DPA) and have lower core wet densities and levels of wet heat resistance than wild-type or ger3 spores. These properties of ger3 spoVA and sleB spoVA spores are identical to those of ger3 spoVF and sleB spoVF spores that lack DPA due to deletion of the spoVF operon coding for DPA synthetase. Sporulation in the presence of exogenous DPA restored DPA levels in ger3 spoVF spores to 53% of the wild-type spore levels, but there was no incorporation of exogenous DPA into ger3 spoVA spores. These data indicate that one or more products of the spoVA operon are involved in DPA transport into the developing forespore during sporulation.

scholarly journals The Germination-Specific Lytic Enzymes SleB, CwlJ1, and CwlJ2 Each Contribute to Bacillus anthracis Spore Germination and Virulence

2009 ◽  
Vol 191 (18) ◽  
pp. 5569-5576 ◽  
Author(s):  
Jonathan D. Giebel ◽  
Katherine A. Carr ◽  
Erica C. Anderson ◽  
Philip C. Hanna
Keyword(s):  
Bacillus Anthracis ◽  
Spore Germination ◽  
Small Subset ◽  
Wild Type ◽  
Lytic Enzymes ◽  
Phenotypic Analysis ◽  
Rich Media ◽  
Order Of Magnitude ◽  
Forming Efficiency

ABSTRACT The bacterial spore cortex is critical for spore stability and dormancy and must be hydrolyzed by germination-specific lytic enzymes (GSLEs), which allows complete germination and vegetative cell outgrowth. We created in-frame deletions of three genes that encode GSLEs that have been shown to be active in Bacillus anthracis germination: sleB, cwlJ1, and cwlJ2. Phenotypic analysis of individual null mutations showed that the removal of any one of these genes was not sufficient to disrupt spore germination in nutrient-rich media. This finding indicates that these genes have partially redundant functions. Double and triple deletions of these genes resulted in more significant defects. Although a small subset of ΔsleB ΔcwlJ1 spores germinate with wild-type kinetics, for the overall population there is a 3-order-of-magnitude decrease in the colony-forming efficiency compared with wild-type spores. ΔsleB ΔcwlJ1 ΔcwlJ2 spores are unable to complete germination in nutrient-rich conditions in vitro. Both ΔsleB ΔcwlJ1 and ΔsleB ΔcwlJ1 ΔcwlJ2 spores are significantly attenuated, but are not completely devoid of virulence, in a mouse model of inhalation anthrax. Although unable to germinate in standard nutrient-rich media, spores lacking SleB, CwlJ1, and CwlJ2 are able to germinate in whole blood and serum in vitro, which may explain the persistent low levels of virulence observed in mouse infections. This work contributes to our understanding of GSLE activation and function during germination. This information may result in identification of useful therapeutic targets for the disease anthrax, as well as provide insights into ways to induce the breakdown of the protective cortex layer, facilitating easier decontamination of resistant spores.

Sign in / Sign up

Export Citation Format

Share Document