Order Caudovirales
Paul Pumpens, Peter Pushko, Philippe Le Mercier in Virus-Like Particles, 2022
As described in the ninth official ICTV report by Lavigne et al. (2012), the Caudovirales order originally consisted of the three huge families of the tailed bacteriophages infecting bacteria and archaea, which were classified by the structure of their tails: Myoviridae with the long contractile tails, Siphoviridae with the long noncontractile tails, and Podoviridae with the short noncontractile tails. Figure 1.1 demonstrates typical images (we will call them portraits) of the representatives of these three great classical families.
Intestinal phages interact with bacteria and are involved in human diseases
Published in Gut Microbes, 2022
The Escherichia virus PDX is a member of the strictly lytic Myoviridae family. It was reported that Myoviridae phage PDX killed a disease-associated enteroaggregative E. coli (EAEC) isolated from a child from rural Tennessee and an EAEC isolated from a child from Columbia in a dose-dependent manner. Cepko LCS et al. further found that EAEC reduced the β-diversity of the human microbiota, while Myoviridae phage PDX could kill EAEC without causing dysregulation of the human microbiome.17 Lytic phages were injected into conventional mice colonized with a group of identified human symbiotic bacteria. Longitudinal tracking of each microbial response using high-throughput sequencing and quantitative PCR showed that phages T4, F1, B40-8, and VD13 lysed only their susceptible bacteria E. coli, Clostridium sporogenes, Bacteroides fragilis and Enterococcus faecalis, respectively. These phages showed no significant effect on other symbiotic bacteria.18 An in vitro small intestine model was used to analyze the effects of a DSM 1058 phage preparation on preselected target E. coli strains and nontarget bacterial populations. It was found that the phage preparation of E. coli DSM 1058 affected only the population number of E. coli. However, other “symbiotic” bacterial species included in the intestinal model, such as Streptococcus salivarius, Streptococcus lutetiensis and E. faecalis, were not affected.19
Fabrication of gelatin/silk fibroin/phage nanofiber scaffold effective against multidrug resistant Pseudomonas aeruginosa
Published in Drug Development and Industrial Pharmacy, 2021
W. A. Sarhan, H. G. Salem, M. A. F. Khalil, I. M. El-Sherbiny, H. M. E. Azzazy
The (MDR) P. aeruginosa strain was utilized to isolate a specific phage from sewage sediment samples collected from different Egyptian hospitals. The isolated phage produced well-defined clear plaques with a diameter range of 2 to 3 mm. Morphological characterization of the isolated phage (Phg) by transmission electron microscope illustrated that the phage has an icosahedral head of 71 nm in diameter and a contractile tail of 110–115 nm in length (Figure 1(a)). Thus, the phage was categorized as a representative of the Myoviridae family [13,39]. The latent period of the isolated Phg was 30 min while its burst size was 617 Phg per cell (Figure 1(b)). The burst size was calculated as the ratio of the mean yield of phage that infected the bacterial cells to the mean phage particles liberated.
Isolation, characterization, and application of Salmonella paratyphi phage KM16 against Salmonella paratyphi biofilm
Published in Biofouling, 2021
Liming Jiang, Rui Zheng, Qiangming Sun, Chenghua Li
Virulent phage KM16 was isolated from slaughterhouse sumps in Kunming, China. The plaque of phage KM16 appeared to be 1mm in diameter after overnight incubation at 37°C (Figure 1a). Negatively stained purified phage KM16 was observed with an electron microscope. Transmission electron microscopy (TEM) revealed that KM16 virions had an icosahedral head 110±5nm in diameter and a noncontractile tail 110±5nm in length (Figure 1b). The morphology of phage KM16 indicated that it belonged to the family Myoviridae. After standing for 5min at 15°C, nearly 85% of the phage particles were adsorbed to the host bacterium S. paratyphi A NA3. After incubation for 20min, almost all phages were adsorbed to the host bacterium S. paratyphi A NA3 (Figure 1c). The one-step growth curves of KM16 propagated in S. paratyphi A NA3 is shown in Figure 1d. KM16 had a latent period of 70min followed by a rise period of 40min.
Related Knowledge Centers
- Archaea
- Bacteria
- Bacteriophage
- Capsomere
- Caudovirales
- Thymidine
- Bacillota
- Gc-Content
- 5-Hydroxymethylcytosine
- Tectivirus