Wommack KE, Ravel J, Hill RT, Colwell RR
Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, Maryland 21202, USA.
Appl Environ Microbiol. 1999 Jan;65(1):241-50. doi: 10.1128/AEM.65.1.241-250.1999.
It has been hypothesized that, by specifically lysing numerically dominant host strains, the virioplankton may play a role in maintaining clonal diversity of heterotrophic bacteria and phytoplankton populations. If viruses selectively lyse only those host species that are numerically dominant, then the number of a specific virus within the virioplankton would be expected to change dramatically over time and space, in coordination with changes in abundance of the host. In this study, the abundances of specific viruses in Chesapeake Bay water samples were monitored, using nucleic acid probes and hybridization analysis. Total virioplankton in a water sample was separated by pulsed-field gel electrophoresis and hybridized with nucleic acid probes specific to either single viral strains or a group of viruses with similar genome sizes. The abundances of specific viruses were inferred from the intensity of the hybridization signal. By using this technique, a virus comprising 1/1,000 of the total virioplankton abundance (ca. 10(4) PFU/ml) could be detected. Titers of either a single virus species or a group of viruses changed over time, increasing to peak abundance and then declining to low or undetectable levels, and were geographically localized in the bay. Peak signal intensities, i.e., peak abundances of virus strains, were 10-fold greater than the low background level. Furthermore, virus species were found to be restricted to a particular depth, since probes specific to viruses from bottom water did not hybridize with virus genomes from surface water at the same geographical location. Overall, changes in abundances of specific viruses within the virioplankton were episodic, supporting the hypothesis that viral infection influences, if not controls, clonal diversity within heterotrophic bacteria and phytoplankton communities.
据推测，通过特异性裂解数量占优势的宿主菌株，浮游病毒可能在维持异养细菌和浮游植物种群的克隆多样性方面发挥作用。如果病毒仅选择性裂解那些数量占优势的宿主物种，那么浮游病毒中特定病毒的数量预计会随着时间和空间发生显著变化，与宿主丰度的变化相协调。在本研究中，使用核酸探针和杂交分析监测了切萨皮克湾水样中特定病毒的丰度。水样中的总浮游病毒通过脉冲场凝胶电泳分离，并与针对单一病毒菌株或一组具有相似基因组大小的病毒的核酸探针杂交。根据杂交信号的强度推断特定病毒的丰度。通过使用这种技术，可以检测到占总浮游病毒丰度1/1000（约10⁴ PFU/ml）的一种病毒。单一病毒物种或一组病毒的滴度随时间变化，增加到峰值丰度，然后下降到低水平或无法检测到的水平，并且在海湾中呈地理定位分布。峰值信号强度，即病毒菌株的峰值丰度，比低背景水平高10倍。此外，发现病毒物种局限于特定深度，因为针对底层水病毒的探针与同一地理位置表层水的病毒基因组不杂交。总体而言，浮游病毒中特定病毒丰度的变化是偶发的，这支持了病毒感染即使不能控制异养细菌和浮游植物群落内的克隆多样性，也会对其产生影响的假设。
