Comparison of ORFs between phages eiAU, eiDWF, and eiMSLS The three phage genomes revealed intensive homology and constrained variability within their gene sequence. The % identity and % similarity of every ORF inside of the 3 phage genomes uncovered that variations exist primarily in predicted ORFs that have no important sequence similarity to sequences in GenBank database and also to ORFs encoding struc tural proteins. ORF14 is predicted to encode a phage tail fiber assembly protein tail assembly chaperone, and in eiAU and eiDWF it’s 100% identical, nevertheless it’s not current in eiMSLS. ORF15 is predicted to encode a tail fiber pro tein and is existing in all 3 phages, with 100% identity in eiAU and eiDWF, even so, it only has 58% identity to its counterpart in eiMSLS.

ORF21 is predicted to encode a phage tail tape measure protein and is pre sent in all 3 phages at about 95% identity at the amino acid degree. ORF23 is predicted to encode a protein homologous to gp15 which is a structural protein that plays a function in cell membrane penetration. this site This ORF is present in all three phages with 83% identity in the amino acid degree. ORF24 is predicted to encode a major tail pro tein and is current in all three phages, with 100% identity between eiDWF and eiMSLS, and with only 90% identity in between individuals two phage and the ORF counterpart in eiAU. Sequence variations in these structural proteins might help describe the distinctions observed during the effi ciency of those phages to kind plaques on several E. icta luri strains.

Nearly all of the structural proteins described over are expected for being concerned in phage infectivity this kind of as adsorption of your phage to your bacterial cell, phage tail length, and cell membrane penetration. Distinctions were also observed while in the ORFs encoding the putative methyltransferases. In phage eiAU, ORF6 kinase inhibitor and ORF7 are predicted to encode a phage methyltrans ferase as well as a DNA N 6 adenine methyltransferase respectively, when in phage eiDWF and eiMSLS just one larger ORF encoding a phage methyltransferase was predicted. Similarly, two methyltransferases are existing from the genomes of one of two extremely related Campylo bacter phages. The authors propose the two methyltransferases could allow the phage to prevent DNA restriction in some strains by means of DNA methylation.

This may perhaps support make clear the variations observed in host selection for the Campylobacter phages at the same time as dif ferences observed in host specificity of your E. ictaluri phages. Consequently, these methyltransferases may likely be concerned in DNA methylation being a implies of staying away from the restriction endonuclease of E. ictaluri. Classification of phages eiAU, eiDWF, and eiMSLS The majority of the best BLAST hits for these phage genomes are to proteins belonging to lytic phages, which include Yersinia phage PY100, Salmonella phage c341, and Enterobacteria phage HK97. All of the elements of a phage lysis cassette had been detected in these phages and no sequence similarity to lysogenic phages or to any part that is definitely related with lysogeny such as integrase recombination linked enzymes, repressor proteins, and anti repressor proteins had been detected. These data as well as final results documenting the lytic capabilities of these phages all indicate that these phages lack mechanisms for integration into the DNA of their host and that they are virulent phages with out the capability for lysogeny. On top of that, none of the predicted proteins have similarities to identified bacter ial pathogenicity things.