Previous Article | Next Article ![]()
Appl. Environ. Microbiol., 04 1996, 1336-1341, Vol 62, No. 4
KE Wommack, RT Hill, TA Muller and RR Colwell
Current estimates of viral abundance in natural waters rely on direct
counts of virus-like particles (VLPs), using either transmission or
epifluorescence microscopy. Direct counts of VLPs, while useful in studies
of viral ecology, do not indicate whether the observed VLPs are capable of
infection and/or replication. Rapid decay in bacteriophage viability under
environmental conditions has been observed. However, it has not been firmly
established whether there is a corresponding degradation of the virus
particles. To address this question, viable and direct counts were carried
out employing two Chesapeake Bay bacteriophages in experimental microcosms
incubated for 56 h at two depths in the York River estuary. Viruses
incubated in situ in microcosms at the surface yielded decay rates in full
sunlight of 0.11 and 0.06 h-1 for CB 38 phi and CB 7 phi, respectively. The
number of infective particles in microcosms in the dark and at a depth of 1
m was not significantly different from laboratory controls, with decay
rates averaging 0.052 h-1 for CB 38 phi and 0.037 h-1 for CB 7 phi. Direct
counts of bacteriophages decreased in teh estuarine microcosms, albeit only
at a rate of 0.028 h-1, and were independent of treatment. Destruction of
virus particles is concluded to be a process separate from loss of
infectivity. It is also concluded that strong sunlight affects the
viability of bacteriophages in surface waters, with the result that direct
counts of VLPs overestimate the number of bacteriophage capable of both
infection and replication. However, in deeper waters, where solar radiation
is not a significant factor, direct counts should more accurately estimate
numbers of viable bacteriophage.
Copyright © 1996, American Society for Microbiology
Effects of sunlight on bacteriophage viability and structure
Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore 21202, USA.
This article has been cited by other articles:
| J. Bacteriol. | Microbiol. Mol. Biol. Rev. | Eukaryot. Cell | All ASM Journals |
|---|