Virophage-like viruses replicate with a candidate phycodnavirus of C. parva

Key results

1. 01

   ShownNeither Larry nor Curly replicates on its own in C. parva, and neither changes host growth.

   Host growth showed no difference from controls (p > 0.05), with cultures peaking near 3.5 × 10^6 cells mL^-1. PLV qPCR copies fell about 10-fold, from ~8 × 10^5 (Larry) and 1 × 10^5 (Curly) copies mL^-1 to ~1 × 10^4 by Day 21. · Results and discussion; Figure legends

2. 02

   ShownThe Imitervirales virus BQ3, the helper of the PLV Moe, does not support Larry or Curly.

   BQ3 lysed the host (~10^5 vs ~2 × 10^6 cells mL^-1 in controls) and rose to ~10^8 copies mL^-1. Both PLVs stayed near inoculum levels (~5 × 10^5 to 10^6 copies mL^-1) for 21 days, and neither altered BQ3 replication (p > 0.025). · Results and discussion; Figure legends

3. 03

   ShownBoth PLVs replicate when co-infecting with the phycodnavirus BQ1.

   Larry and Curly each rose roughly 1000-fold from their inoculum by Day 21 (p < 0.025). TEM of the infection stocks showed particles of ~110 nm (BQ1) and ~70 nm (PLVs). · Results and discussion; Electron Microscopy; Figure legends

4. 04

   ShownCo-infection with either PLV suppresses BQ1 replication, a hyperparasitic pattern.

   BQ1 alone increased 10,000-fold (~10^5 to ~10^9 copies mL^-1) by Day 21, versus a 100-fold increase (~10^7 copies mL^-1) with Larry or Curly (p < 0.008). · Results and discussion; Statistical Analyses

5. 05

   SuggestedThe PLVs' effect on BQ1-induced host lysis is unresolved: Larry may dampen it and Curly may not, but neither difference was significant.

   At Day 21, host density was 9.5 × 10^5 cells mL^-1 with BQ1 alone, 1.5 × 10^6 with BQ1 + Larry and ~6.4 × 10^5 with BQ1 + Curly (p > 0.05). · Results and discussion; Statistical Analyses