Full text loading...
Chapter 36 : Viral Community Structure
This chapter brings together methods that can be used to count and examine the genetic diversity of communities and populations of aquatic viral communities, although many of the methods can be adapted for other environments. The first studies on viral abundance in aquatic systems used transmission electron microscopy (TEM) to count virus-like particles (VLPs). Interestingly, although TEM images of natural communities suggest that viruses with small noncontractile tails are most abundant, the most frequently isolated viruses are tailed sipho-and myoviruses. This discrepancy may be due to the method of sample preparation used in many TEM studies of natural virus communities or due to the fact that viral isolates are not representative of native viral communities. Breitbart et al. constructed a metagenomic library of two coastal DNA phage communities, using the linkeramplified shotgun library (LASL) method. In this study, 200 liters of seawater was prefiltered and concentrated by tangential flow filtration. Community approaches are useful for studies of the total abundance of viral particles or for documentation of the dominant morphotypes in viral communities. Viruses are an abundant, dynamic, and ecologically important component of aquatic ecosystems, and there is now strong evidence that they are the most genetically diverse biological entities on the planet. Targeting the viral DNA polymerase, this research revealed a vast amount of genetic variation that was not represented in cultures and showed that very similar sequences were distributed on a global scale.
Key Concept Ranking
- Denaturing Gradient Gel Electrophoresis