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Thompson J, Barr C, Babcock-Adams L, Bird L, La Cava E, Garber A, Hongoh Y, Liu M, Nealson KH, Okamoto A, Repeta D, Suzuki S, Tacto C, Tashjian M, Merino N. Insights into the physiological and genomic characterization of three bacterial isolates from a highly alkaline, terrestrial serpentinizing system. Front Microbiol 2023; 14:1179857. [PMID: 37520355 PMCID: PMC10373932 DOI: 10.3389/fmicb.2023.1179857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/23/2023] [Indexed: 08/01/2023] Open
Abstract
The terrestrial serpentinite-hosted ecosystem known as "The Cedars" is home to a diverse microbial community persisting under highly alkaline (pH ~ 12) and reducing (Eh < -550 mV) conditions. This extreme environment presents particular difficulties for microbial life, and efforts to isolate microorganisms from The Cedars over the past decade have remained challenging. Herein, we report the initial physiological assessment and/or full genomic characterization of three isolates: Paenibacillus sp. Cedars ('Paeni-Cedars'), Alishewanella sp. BS5-314 ('Ali-BS5-314'), and Anaerobacillus sp. CMMVII ('Anaero-CMMVII'). Paeni-Cedars is a Gram-positive, rod-shaped, mesophilic facultative anaerobe that grows between pH 7-10 (minimum pH tested was 7), temperatures 20-40°C, and 0-3% NaCl concentration. The addition of 10-20 mM CaCl2 enhanced growth, and iron reduction was observed in the following order, 2-line ferrihydrite > magnetite > serpentinite ~ chromite ~ hematite. Genome analysis identified genes for flavin-mediated iron reduction and synthesis of a bacillibactin-like, catechol-type siderophore. Ali-BS5-314 is a Gram-negative, rod-shaped, mesophilic, facultative anaerobic alkaliphile that grows between pH 10-12 and temperatures 10-40°C, with limited growth observed 1-5% NaCl. Nitrate is used as a terminal electron acceptor under anaerobic conditions, which was corroborated by genome analysis. The Ali-BS5-314 genome also includes genes for benzoate-like compound metabolism. Anaero-CMMVII remained difficult to cultivate for physiological studies; however, growth was observed between pH 9-12, with the addition of 0.01-1% yeast extract. Anaero-CMMVII is a probable oxygen-tolerant anaerobic alkaliphile with hydrogenotrophic respiration coupled with nitrate reduction, as determined by genome analysis. Based on single-copy genes, ANI, AAI and dDDH analyses, Paeni-Cedars and Ali-BS5-314 are related to other species (P. glucanolyticus and A. aestuarii, respectively), and Anaero-CMMVII represents a new species. The characterization of these three isolates demonstrate the range of ecophysiological adaptations and metabolisms present in serpentinite-hosted ecosystems, including mineral reduction, alkaliphily, and siderophore production.
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Affiliation(s)
- Jaclyn Thompson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Casey Barr
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Lydia Babcock-Adams
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Lina Bird
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC, United States
| | - Eugenio La Cava
- National Institute for Materials Science, Tsukuba, Ibaraki, Japan
| | - Arkadiy Garber
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, United States
| | - Yuichi Hongoh
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Mark Liu
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Kenneth H. Nealson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Akihiro Okamoto
- Research Center for Macromolecules and Biomaterials, National Institute for Materials Science, Tsukuba, Japan
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
- Graduate School of Science and Technology, University of Tsukuba, Tsukuba, Japan
| | - Daniel Repeta
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Shino Suzuki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Sagamihara, Kanagawa, Japan
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), JAMSTEC, Yokosuka, Kanagawa, Japan
| | - Clarissa Tacto
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Michelle Tashjian
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
| | - Nancy Merino
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, United States
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Khazaal S, Al Safadi R, Osman D, Hiron A, Gilot P. Streptococcus agalactiae imports spermidine by a member of the amino acid/polyamine antiporter family to endure citric acid stress at the vaginal pH. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35920804 DOI: 10.1099/mic.0.001219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Polyamines bind to various cellular components, such as nucleic acids, phospholipids, proteins and nucleotides. They are involved in the virulence and protection against physiological stresses of several bacterial species. Streptococcus agalactiae is able to colonize the vaginal tract of asymptomatic pregnant women and to resist, by an as yet poorly characterized mechanism, pH 4.0, the low physiological pH of this environment. We identified a transporter of the amino acid/polyamine antiporter family (SAK_1604 in strain A909) that shares 39.8 % similar amino acids with CadB and 34.7 % with PotE, two transporters implicated in acid resistance in Escherichia coli. We found that sak_1604 is overexpressed in the presence of spermidine and during citric acid stress at the vaginal pH, but not during lactic acid or HCl stresses at the same pH or during a sodium citrate stress at pH 7.4. Dihydrogen citrate is the predominant form of citric acid at pH 4.0. Using a deletion mutant, we proved that SAK_1604 is involved in the survival of S. agalactiae during citric acid stress at pH 4.0 in the presence of spermidine, and we showed by TLC analysis that it is involved in spermidine transport in these conditions. Our data open new perspectives on the comprehension of the molecular mechanisms allowing S. agalactiae to survive at the physiological pH of the vagina and on the unsuspected role of an ionic form of citric acid.
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Affiliation(s)
- Sarah Khazaal
- ISP, Bactéries et Risque Materno-Foetal, Université de Tours, INRAE, 37032 Tours, France.,LBA3B, AZM Center for Research in Biotechnology and its Applications, EDST, Lebanese University, Tripoli 1300, Lebanon
| | - Rim Al Safadi
- LBA3B, AZM Center for Research in Biotechnology and its Applications, EDST, Lebanese University, Tripoli 1300, Lebanon
| | - Dani Osman
- LBA3B, AZM Center for Research in Biotechnology and its Applications, EDST, Lebanese University, Tripoli 1300, Lebanon
| | - Aurélia Hiron
- ISP, Bactéries et Risque Materno-Foetal, Université de Tours, INRAE, 37032 Tours, France
| | - Philippe Gilot
- ISP, Bactéries et Risque Materno-Foetal, Université de Tours, INRAE, 37032 Tours, France
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