VOLN27B: A New Head-Tailed Halovirus Isolated from an Underground Salt Crystal and Infecting Halorubrum

Figure 5

One-step-growth-curve of VOLN27B infecting cells of strain Halorubrum sp. LN27 and of morphotype VOLN27B virions. Growth of uninfected (red line with filled red circle) and virus infected () (black line with filled black square) Halorubrum sp. LN27 was determined by measuring the absorbance at 600 nm () (a). Virus titer in virus infected Halorubrum sp. LN27 supernatant was determined by plaque formation assay using Halorubrum sp. LN27 as lawn cells (gray bars). A significant production of viruses started at 10 h postinfection (p.i.). And at 18 h p.i., the turbidity of cell suspension began to decline significantly. At 21 h p.i., the virus titer reached the maximum (a). To determining the maturing time for VOLN27B in cells of strain Halorubrum sp. LN27, the free viruses were removed by washing with sterilized 20% NaCl solution for three times after conducting the infection. Cells collected from 100 μL cell suspension by centrifugation (12,000 rpm. 3 min, 4°C) were lysed with sterilized ddH₂O (500 μL); then, the lysates were used to perform plaque formation assay immediately. Infectious viruses were detected at 8 h p.i. (b). Morphotype of VOLN27B was determined by using transmission electron micrograph (JEM-1400, JEOL, Japan) after staining with 3% () uranyl acetate (pH 4.5). Arrowheads show the intact virus particles. Scale bar, 100 nm (c).

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