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Munir Ahamed J, Dahms HU, Schizas NV, Rathinam AJ, Ouddane B, Huang YL. Isolation of Pseudonocardia strains associated with the shallow water hydrothermal vent crab Xenograpsus testudinatus from a metal-rich environment: Biochemical characterization and enzymatic characterization, molecular identification, antibacterial, antibiofilm and antioxidant activity. Microb Pathog 2025; 203:107457. [PMID: 40058416 DOI: 10.1016/j.micpath.2025.107457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2025] [Revised: 02/17/2025] [Accepted: 03/06/2025] [Indexed: 03/15/2025]
Abstract
A shallow hydrothermal vent at Kueishantao Island, Taiwan provides a challenging environment and has been less explored for its microbial communities, especially the actinomycetes and their antibacterial and antioxidant activity. Nine actinomycete strains were isolated from the endemic hydrothermal vent crab Xenograpsus testudinatus and were identified as belonging to the rare actinomycete genus Pseudonocardia sp. Physiochemical results showed that the optimum growth conditions of these nine isolates were at pH 7, 35 °C, and 0.5-2% NaCl. Biochemical characterization showed differences between the strains. These isolates were further characterized at genetic barcoding (16s rRNA sequencing) and phenotypic levels and identified at the species/strain level as Pseudonocardia alni SCSW01, Pseudonocardia yuanmonensis SCSW02, Pseudonocardia sp. strains SCSW03, SCSW04, SCSW05, SCSW06, BCSW29, ECSW09, and ECSW018. The morphology of the strains was analyzed using an environmental scanning electron microscope (ESEM). The nine isolates showed potential antibacterial activity against gram-positive and gram-negative pathogenic strains. The confocal laser scanning microscopy (CLSM) images show live and dead cells and biofilm/antibiofilm activity of the actinomycete supernatant and crude extracts against pathogenic bacterial strains. The crude extracts of SCSW02, SCSW06, BCSW29, ECSW09, and ECSW018 showed antibiofilm activity against P. aeruginosa, E. coli, and S. aureus. The antioxidant activity such as DPPH and H2O2 scavenging assay results showed that the nine actinomycetes crude extracts hold more substantial radical scavenging properties than supernatants. Our results marked the first report of Pseudonocardia genera from the vent crab Xenograpsus testudinatus of the HV region at Kueishantao island, Taiwan.
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Affiliation(s)
- Johnthini Munir Ahamed
- Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Hans-Uwe Dahms
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan; Research Center for Precision Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan; Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan.
| | - Nikolaos V Schizas
- Department of Marine Sciences, University of Puerto Rico, Mayagüez, Call Box 9000, PR, 00681, USA
| | - Arthur James Rathinam
- Department of Marine Science, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Baghdad Ouddane
- University of Lille, Laboratoire de Spectroscopie pour les Interactions, la Réactivité et l'Environnement, IREPSE Institute, Lille, France
| | - Yeou Lih Huang
- Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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