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Gao Y, Amon JD, Brogan AP, Artzi L, Ramírez-Guadiana FH, Cofsky JC, Kruse AC, Rudner DZ. SpoVAF and FigP assemble into oligomeric ion channels that enhance spore germination. Genes Dev 2024; 38:31-45. [PMID: 38242633 PMCID: PMC10903944 DOI: 10.1101/gad.351353.123] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 01/04/2024] [Indexed: 01/21/2024]
Abstract
Bacterial spores can remain dormant for decades yet rapidly germinate and resume growth in response to nutrients. GerA family receptors that sense and respond to these signals have recently been shown to oligomerize into nutrient-gated ion channels. Ion release initiates exit from dormancy. Here, we report that a distinct ion channel, composed of SpoVAF (5AF) and its newly discovered partner protein, YqhR (FigP), amplifies the response. At high germinant concentrations, 5AF/FigP accelerate germination; at low concentrations, this complex becomes critical for exit from dormancy. 5AF is homologous to the channel-forming subunit of GerA family receptors and is predicted to oligomerize around a central pore. 5AF mutations predicted to widen the channel cause constitutive germination during spore formation and membrane depolarization in vegetative cells. Narrow-channel mutants are impaired in germination. A screen for suppressors of a constitutively germinating 5AF mutant identified FigP as an essential cofactor of 5AF activity. We demonstrate that 5AF and FigP interact and colocalize with GerA family receptors in spores. Finally, we show that 5AF/FigP accelerate germination in B. subtilis spores that have nutrient receptors from another species. Our data support a model in which nutrient-triggered ion release by GerA family receptors activates 5AF/FigP ion release, amplifying the response to germinant signals.
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Affiliation(s)
- Yongqiang Gao
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jeremy D Amon
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Anna P Brogan
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Lior Artzi
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | - Joshua C Cofsky
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David Z Rudner
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA;
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2
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Tezuka T, Mitsuyama K, Date R, Ohnishi Y. A unique sigma/anti-sigma system in the actinomycete Actinoplanes missouriensis. Nat Commun 2023; 14:8483. [PMID: 38123564 PMCID: PMC10733313 DOI: 10.1038/s41467-023-44291-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/07/2023] [Indexed: 12/23/2023] Open
Abstract
Bacteria of the genus Actinoplanes form sporangia that contain dormant sporangiospores which, upon contact with water, release motile spores (zoospores) through a process called sporangium dehiscence. Here, we set out to study the molecular mechanisms behind sporangium dehiscence in Actinoplanes missouriensis and discover a sigma/anti-sigma system with unique features. Protein σSsdA contains a functional sigma factor domain and an anti-sigma factor antagonist domain, while protein SipA contains an anti-sigma factor domain and an anti-sigma factor antagonist domain. Remarkably, the two proteins interact with each other via the anti-sigma factor antagonist domain of σSsdA and the anti-sigma factor domain of SipA. Although it remains unclear whether the SipA/σSsdA system plays direct roles in sporangium dehiscence, the system seems to modulate oxidative stress responses in zoospores. In addition, we identify a two-component regulatory system (RsdK-RsdR) that represses initiation of sporangium dehiscence.
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Affiliation(s)
- Takeaki Tezuka
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
- Graduate School of Infection Control Sciences, Kitasato University, Minato-ku, Tokyo, Japan.
| | - Kyota Mitsuyama
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Risa Date
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yasuo Ohnishi
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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3
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Lu S, Liao X, Lu W, Zhang L, Na K, Li X, Guo X. L-Alanine promotes anti-infectious properties of Bacillus subtilis S-2 spores via the germination receptor gerAA. Probiotics Antimicrob Proteins 2023:10.1007/s12602-023-10121-2. [PMID: 37439954 DOI: 10.1007/s12602-023-10121-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2023] [Indexed: 07/14/2023]
Abstract
Bacillus species, which have two cell-type forms (vegetative cells and spores), demonstrate a variety of probiotic functions in animal feed additives and human nutrition. We previously found that the probiotic effect of Bacillus subtilis S-2 spores with high germination response to L-alanine was specifically enhanced by the L-alanine pretreatment. The germination response of Bacillus is highly associated with the germination receptors of spores. However, how L-alanine-induced germination of spores exerts anti-infectious effect in epithelial cells remains unclear. In this study, we constructed the mutant strain of B. subtilis S-2 with germination receptor gerAA knockout to further explore the role of spore germination in resisting pathogen infection to cells. The differential probiotic effects of B. subtilis S-2 and S-2ΔgerAA spores pretreated with L-alanine were evaluated in intestinal porcine epithelial cells (IPEC-J2) or Caco2 cells infected with enterotoxigenic Escherichia coli (ETEC) or following IL-1β stimulation. The results showed that the germination response of the S-2ΔgerAA spores to L-alanine was significantly reduced. Compared with the S-2ΔgerAA spores, the L-alanine-induced germination of B. subtilis S-2 spores significantly increased the activity of anti-adhesion of ETEC to IPEC-J2 cells and reduced the expression of inflammatory factors and cell receptors. L-alanine induction also significantly promoted the expression of autophagy-related proteins in the B. subtilis S-2 spores. These findings demonstrate that the gerAA germination receptor is essential for the probiotic function of Bacillus spores and that L-alanine treatment promotes the anti-infectious properties of the germinated spores in porcine intestinal epithelial IPEC-J2 cells. The result suggests the importance of germination receptor gerAA in helping spore germination and enhancing anti-infectious activity. The findings in the study benefit to screening of potential Bacillus probiotics and increasing probiotic efficacy induced by L-alanine as an adjuvant.
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Affiliation(s)
- Shuang Lu
- College of Life Science, South-Central Minzu University, No. 182, Minyuan Road, Wuhan City, 430074, China
| | - Xianying Liao
- College of Life Science, South-Central Minzu University, No. 182, Minyuan Road, Wuhan City, 430074, China
| | - Wei Lu
- College of Life Science, South-Central Minzu University, No. 182, Minyuan Road, Wuhan City, 430074, China
| | - Li Zhang
- College of Life Science, South-Central Minzu University, No. 182, Minyuan Road, Wuhan City, 430074, China
| | - Kai Na
- College of Life Science, South-Central Minzu University, No. 182, Minyuan Road, Wuhan City, 430074, China
| | - Xiangyu Li
- CABIO Bioengineering (Wuhan) Co., Ltd, Wuhan City, 430074, China
| | - Xiaohua Guo
- College of Life Science, South-Central Minzu University, No. 182, Minyuan Road, Wuhan City, 430074, China.
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Liggins M, Ramírez Ramírez N, Abel-Santos E. Comparison of sporulation and germination conditions for Clostridium perfringens type A and G strains. Front Microbiol 2023; 14:1143399. [PMID: 37228374 PMCID: PMC10203408 DOI: 10.3389/fmicb.2023.1143399] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 04/14/2023] [Indexed: 05/27/2023] Open
Abstract
Clostridium perfringens is a spore forming, anaerobic, Gram-positive bacterium that causes a range of diseases in humans and animals. C. perfringens forms spores, structures that are derived from the vegetative cell under conditions of nutrient deprivation and that allows survival under harsh environmental conditions. To return to vegetative growth, C. perfringens spores must germinate when conditions are favorable. Previous work in analyzing C. perfringens spore germination has produced strain-specific results. Hence, we analyzed the requirements for spore formation and germination in seven different C. perfringens strains. Our data showed that C. perfringens sporulation conditions are strain-specific, but germination responses are homogenous in all strains tested. C. perfringens spores can germinate using two distinct pathways. The first germination pathway (the amino acid-only pathway or AA) requires L-alanine, L-phenylalanine, and sodium ions (Na+) as co-germinants. L-arginine is not a required germinant but potentiates germination. The AA pathway is inhibited by aromatic amino acids and potassium ions (K+). Bicarbonate (HCO3-), on the other hand, bypasses potassium-mediated inhibition of C. perfringens spore germination through the AA pathway. The second germination pathway (the bile salt / amino acid pathway or BA) is more promiscuous and is activated by several bile salts and amino acids. In contrast to the AA pathway, the BA pathway is insensitive to Na+, although it can be activated by either K+ or HCO3-. We hypothesize that some C. perfringens strains may have evolved these two distinct germination pathways to ensure spore response to different host environments.
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Affiliation(s)
- Marc Liggins
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Norma Ramírez Ramírez
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, United States
- Departamento de Biología, Universidad de Guanajuato, Guanajuato, Mexico
| | - Ernesto Abel-Santos
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV, United States
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Gao Y, Amon JD, Artzi L, Ramírez-Guadiana FH, Brock KP, Cofsky JC, Marks DS, Kruse AC, Rudner DZ. Bacterial spore germination receptors are nutrient-gated ion channels. Science 2023; 380:387-391. [PMID: 37104613 PMCID: PMC11154005 DOI: 10.1126/science.adg9829] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/29/2023] [Indexed: 04/29/2023]
Abstract
Bacterial spores resist antibiotics and sterilization and can remain metabolically inactive for decades, but they can rapidly germinate and resume growth in response to nutrients. Broadly conserved receptors embedded in the spore membrane detect nutrients, but how spores transduce these signals remains unclear. Here, we found that these receptors form oligomeric membrane channels. Mutations predicted to widen the channel initiated germination in the absence of nutrients, whereas those that narrow it prevented ion release and germination in response to nutrients. Expressing receptors with widened channels during vegetative growth caused loss of membrane potential and cell death, whereas the addition of germinants to cells expressing wild-type receptors triggered membrane depolarization. Therefore, germinant receptors act as nutrient-gated ion channels such that ion release initiates exit from dormancy.
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Affiliation(s)
- Yongqiang Gao
- Department of Microbiology, Harvard Medical ScF(2hool, 77 Avenue Louis Pasteur, Boston MA 02115
| | - Jeremy D. Amon
- Department of Microbiology, Harvard Medical ScF(2hool, 77 Avenue Louis Pasteur, Boston MA 02115
- Present Address: Moderna Genomics, 200 Technology Square, Cambridge MA 02139
| | - Lior Artzi
- Department of Microbiology, Harvard Medical ScF(2hool, 77 Avenue Louis Pasteur, Boston MA 02115
- Present Address: Evolved By Nature, 196 Boston Ave, Medford MA 02155
| | | | - Kelly P. Brock
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Boston MA 02115
- Present Address: Kernal Biologics, 238 Main Street, Cambrdige MA 02142
| | - Joshua C. Cofsky
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston MA 02115
| | - Deborah S. Marks
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Boston MA 02115
| | - Andrew C. Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston MA 02115
| | - David Z. Rudner
- Department of Microbiology, Harvard Medical ScF(2hool, 77 Avenue Louis Pasteur, Boston MA 02115
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6
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Gao Y, Barajas-Ornelas RDC, Amon JD, Ramírez-Guadiana FH, Alon A, Brock KP, Marks DS, Kruse AC, Rudner DZ. The SpoVA membrane complex is required for dipicolinic acid import during sporulation and export during germination. Genes Dev 2022; 36:634-646. [PMID: 35654455 PMCID: PMC9186386 DOI: 10.1101/gad.349488.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/16/2022] [Indexed: 11/24/2022]
Abstract
In response to starvation, endospore-forming bacteria differentiate into stress-resistant spores that can remain dormant for years yet rapidly germinate and resume growth in response to nutrients. The small molecule dipicolinic acid (DPA) plays a central role in both the stress resistance of the dormant spore and its exit from dormancy during germination. The spoVA locus is required for DPA import during sporulation and has been implicated in its export during germination, but the molecular bases are unclear. Here, we define the minimal set of proteins encoded in the Bacillus subtilis spoVA operon required for DPA import and demonstrate that these proteins form a membrane complex. Structural modeling of these components combined with mutagenesis and in vivo analysis reveal that the C and Eb subunits form a membrane channel, while the D subunit functions as a cytoplasmic plug. We show that point mutations that impair the interactions between D and the C-Eb membrane complex reduce the efficiency of DPA import during sporulation and reciprocally accelerate DPA release during germination. Our data support a model in which DPA transport into spores involves cycles of unplugging and then replugging the C-Eb membrane channel, while nutrient detection during germination triggers DPA release by unplugging it.
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Affiliation(s)
- Yongqiang Gao
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | - Jeremy D Amon
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | - Assaf Alon
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Kelly P Brock
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Debora S Marks
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - David Z Rudner
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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7
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Genetic suppression meets structure prediction: probing a spore germination receptor complex. J Bacteriol 2021; 204:e0057921. [PMID: 34871033 DOI: 10.1128/jb.00579-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite the thousands of spore germinant receptor operons identified in genomes of Bacilli and Clostridia, understanding how the three essential receptor components act as a signal transduction machine in germination remains limited. The paper by Amon et al in this issue uses the classical genetic approach of suppression to define a region of likely interaction between the GerAA and GerAB proteins: it provides a first glimpse into potential events within the receptor complex.
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