Amicon ultra 0.5 ml centrifugal filter units 100k

With respect to TEM, the samples were prepared by exchanging a high-titer phage lysate in HEPES buffer via Amicon Ultra −0.5 mL Centrifugal Filter Units 100K (Merck, Darmstadt, Germany). The phages then adsorbed on glow discharged formvar-carbon-coated nickel grids (Maxtaform, 200 mesh, Plano, Wetzlar, Germany) for 10 min. Afterwards the samples were stained with a drop of 1% phosphotungstic acid (in aqua dest., adjusted to pH 7.2; Agar Scientific Ltd., Stansted, United Kingdom) and then air-dried before they were examined using a TEM LEO 906 (Carl Zeiss, Oberkochen, Germany), operating at an acceleration voltage of 60 kV. For photography, a wide-angle Dual Speed 2K-CCD-Camera 14 bit (Tröndle, TRS Moorenweis, Germany) and the analysis software IMAGE SP Professional (SISPROG, Tröndle, Moorenweis, Germany) were used. A description of phage morphology, and determination of the size of phage head and tails, were performed based on five selected virions displayed on the electron micrographs (average size ± standard deviation).

To visualize the phage morphology, 1 mL of phage lysate was concentrated in two steps via Amicon Ultra-0.5 mL Centrifugal Filter Units 100 K (Merck, Darmstadt, Germany). The purified phage suspension was dripped onto a carbon-formvar coated with a 200 mesh grid and fixed for 1 min, and the extra liquid was removed by tight contact with absorbent paper. Grids were air-dried for 30 s at room temperature before being negatively stained with UranyLess (Delta Microscopie, Mauressac, France), according to the manufacturer’s recommendations. After air drying, grids were examined using a TEM JEM 1010 (JEOL Europe SAS), operating at an acceleration voltage of 80 kV.

High-titer phage lysate was exchanged in HEPES buffer via Amicon Ultra-0.5 mL Centrifugal Filter Units 100 K (Merck, Darmstadt, Germany). Phages were allowed to adsorb on glow discharged formvar-carbon-coated nickel grids (Maxtaform, 200 mesh, Plano, Wetzlar, Germany) for 10 min. Samples on grids were stained by placing on a drop of 1% phosphotungstic acid (in aqua dest., adjusted to pH 7.2; Agar Scientific Ltd., Stansted, United Kingdom). After air drying, samples were examined using a TEM LEO 906 (Carl Zeiss, Oberkochen, Germany), operating at an acceleration voltage of 60 kV.
Wide-angle Dual Speed 2K-CCD-Camera 14 bit (Tröndle, TRS Moorenweis, Germany) and analysis software IMAGE SP Professional (SISPROG, Tröndle, Moorenweis, Germany) were used to photograph observations.
Description of phage morphology and determination of the size of phage head and tails were performed based on five selected virions displayed on the electron micrographs (average size ± standard deviation is given).