EESS talk on "Exploratory hunt for viruses uncovers diverse phages in alpine streams"
Event details
| Date | 15.04.2025 |
| Hour | 12:15 › 13:15 |
| Speaker | Wai Hoe Chin, Postdoctoral Researcher, RIVER |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
Abstract:
Streams are lifelines that perfuse Earth’s landscape. Crucially, complex microbial communities organised as biofilms colonise streambeds, drive critical ecological processes, and regulate biogeochemical cycles. While the global impacts of stream biofilms are increasingly recognised, viruses that infect bacteria to propagate – namely bacteriophages (phages) – remain largely unexplored. Here, we present a pioneering effort to isolate and characterise phages from alpine streams. Briefly, we collected >120 L of water from a Swiss mountain stream which was filtered for viruses only and concentrated by 300-fold using tangential flow. We then screened the viral concentrate on 40 bacterial hosts previously isolated from mountain stream biofilms using soft-agar medium in petri dishes. Visible plaques on the soft-agar caused by phage-killing on bacterial lawns, were cored and double-purified. Our efforts yielded over 60 phage isolates spanning across 15 bacterial host species exhibiting a diverse range of plaque morphologies. Electron microscopy of our isolates further revealed viral structure of primarily tailed phages, namely myo-, sipho-, and podoviruses. We report phage genomes sizes ranging from ~40 to 200 kb upon sequencing a subset of our collection. These isolates are also novel in that they are not found or recorded in contemporary public genome databases. Closer inspection of these genomes revealed genetic microdiversity amongst phage groups isolated from the same host species. This implies that phages may be adapting alongside microdiverse bacterial communities from their native stream environment. Finally, we preliminarily tested the virulent activity of our phage isolates against statically grown bacterial biofilms and intriguingly reported little-to-no biofilm disruption despite increasing phage dosage. We envisage to extend our study by leveraging microfluidics with real-time imaging to better examine phage-biofilm interactions under hydrodynamic conditions reported in alpine streams. As of date, our exploration uncovered an unprecedented assortment of phages from the alpine environment that remains hitherto untapped and unstudied.
Biography:
Wai Hoe Chin is a postdoctoral researcher at the River Ecosystems Laboratory located in EPFL Valais. Here, his research focuses on uncovering the role and impact bacterial viruses exert on vast microbial communities in our streams and rivers. Prior to joining EPFL and the field of environmental sciences, he was a postdoctoral scholar at San Diego State University in the US, and a PhD alumni of Monash University, Australia. During then, his expertise was involved in applying bacteriophages to combat chronic bacterial infections and revealing the evolutionary mechanisms adopted by bacteriophages to persist in mammalian mucosal membranes, respectively.
Streams are lifelines that perfuse Earth’s landscape. Crucially, complex microbial communities organised as biofilms colonise streambeds, drive critical ecological processes, and regulate biogeochemical cycles. While the global impacts of stream biofilms are increasingly recognised, viruses that infect bacteria to propagate – namely bacteriophages (phages) – remain largely unexplored. Here, we present a pioneering effort to isolate and characterise phages from alpine streams. Briefly, we collected >120 L of water from a Swiss mountain stream which was filtered for viruses only and concentrated by 300-fold using tangential flow. We then screened the viral concentrate on 40 bacterial hosts previously isolated from mountain stream biofilms using soft-agar medium in petri dishes. Visible plaques on the soft-agar caused by phage-killing on bacterial lawns, were cored and double-purified. Our efforts yielded over 60 phage isolates spanning across 15 bacterial host species exhibiting a diverse range of plaque morphologies. Electron microscopy of our isolates further revealed viral structure of primarily tailed phages, namely myo-, sipho-, and podoviruses. We report phage genomes sizes ranging from ~40 to 200 kb upon sequencing a subset of our collection. These isolates are also novel in that they are not found or recorded in contemporary public genome databases. Closer inspection of these genomes revealed genetic microdiversity amongst phage groups isolated from the same host species. This implies that phages may be adapting alongside microdiverse bacterial communities from their native stream environment. Finally, we preliminarily tested the virulent activity of our phage isolates against statically grown bacterial biofilms and intriguingly reported little-to-no biofilm disruption despite increasing phage dosage. We envisage to extend our study by leveraging microfluidics with real-time imaging to better examine phage-biofilm interactions under hydrodynamic conditions reported in alpine streams. As of date, our exploration uncovered an unprecedented assortment of phages from the alpine environment that remains hitherto untapped and unstudied.
Biography:
Wai Hoe Chin is a postdoctoral researcher at the River Ecosystems Laboratory located in EPFL Valais. Here, his research focuses on uncovering the role and impact bacterial viruses exert on vast microbial communities in our streams and rivers. Prior to joining EPFL and the field of environmental sciences, he was a postdoctoral scholar at San Diego State University in the US, and a PhD alumni of Monash University, Australia. During then, his expertise was involved in applying bacteriophages to combat chronic bacterial infections and revealing the evolutionary mechanisms adopted by bacteriophages to persist in mammalian mucosal membranes, respectively.
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Prof. Tom Battin, RIVER