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Bacteriophage-like particles associated with the gene transfer agent of methanococcus voltae PS
F Eiserling1, A Pushkin1, M Gingery1
1Department of Microbiology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA1.
Abstract:
The methanogenic archaeobacterium Methanococcus voltae (strain PS) is known to produce a filterable, DNase-resistant agent (called VTA, for voltae transfer agent), which carries very small fragments (4400 bp) of bacterial DNA and is able to transduce bacterial genes between derivatives of the strain. Examination by electron microscopy of two preparations of VTA that were concentrated and partially purified by different methods showed virus-like particles with isometric heads, about 40 nm in diameter, and with 61 nm long tails. These particles co-sedimented with the minute bacteriophage φX174 in a sucrose density gradient.
Insights
Methanococcus voltae produces a voltae transfer agent (VTA) that transfers bacterial DNA. Electron microscopy revealed VTA contains virus-like particles capable of gene transduction.
Area of Science:
- Microbiology
- Archaea
- Virology
Background:
- Methanococcus voltae is a methanogenic archaeobacterium.
- It produces a filterable, DNase-resistant agent known as voltae transfer agent (VTA).
- VTA transfers small bacterial DNA fragments (4400 bp) and transduces genes between strain derivatives.
Purpose of the Study:
- To characterize the physical nature of the voltae transfer agent (VTA).
- To investigate the morphology of VTA particles.
- To determine the properties of VTA relevant to its function in gene transfer.
Main Methods:
- Concentration and partial purification of VTA.
- Electron microscopy for particle visualization.
- Sucrose density gradient centrifugation for co-sedimentation analysis.
Main Results:
- Electron microscopy revealed virus-like particles in VTA preparations.
- These particles possess isometric heads (approx. 40 nm diameter) and long tails (approx. 61 nm).
- VTA particles co-sedimented with the minute bacteriophage φX174, indicating similar size and density.
Conclusions:
- Voltae transfer agent (VTA) from Methanococcus voltae consists of virus-like particles.
- These particles are likely responsible for the observed DNA transfer and gene transduction.
- The morphology and sedimentation properties suggest a potential relationship with known bacteriophages.