Genome sequence of the novel virulent bacteriophage PMBT14 with lytic activity against Pseudomonas fluorescens DSM 50090R.

Psychrotrophic gram-negative Pseudomonas spp. represent a serious problem in the dairy industry as they can cause spoilage of milk and dairy products. Bacteriophages have moved into focus as promising biocontrol agents for such food spoilage bacteria. The virulent Siphoviridae phage PMBT14 was isolated on a mutant variant of P. fluorescens DSM 50090 challenged with an unrelated virulent P. fluorescens DSM 50090 Podoviridae phage (i.e., mutant strain DSM 50090R). PMBT14 has a 47,820-bp dsDNA genome with 76 predicted open reading frames (ORFs). Its genome shows no significant sequence similarity to that of known phages, suggesting that PMBT14 represents a novel phage. Phage PMBT14 could be a promising biocontrol agent for P. fluorescens in milk or dairy foods.

Identification and characterization of cis- and trans-acting elements involved in prophage induction in Streptococcus thermophilus†J34.

The genetic switch region of temperate Streptococcus thermophilus phage TP-J34 contains two divergently oriented promoters and several predicted operator sites. It separates lytic cycle-promoting genes from those promoting lysogeny. A polycistronic transcript comprises the genes coding for repressor Crh, metalloproteinase-motif protein Rir and superinfection exclusion lipoprotein Ltp. Weak promoters effecting monocistronic transcripts were localized for ltp and int (encoding integrase) by Northern blot and 5'-RACE-PCR. These transcripts appeared in lysogenic as well as lytic state. A polycistronic transcript comprising genes coh (encoding Cro homolog), ant (encoding putative antirepressor), orf7, orf8 and orf9 was only detected in the lytic state. Four operator sites, of which three were located in the intergenic regions between crh and coh, and one between coh and ant, were identified by competition electromobility shift assays. Cooperative binding of Crh to two operator sites immediately upstream of coh could be demonstrated. Coh was shown to bind to the operator closest to crh only. Oligomerization was proven by cross-linking Crh by glutaraldehyde. Knock-out of rir revealed a key role in prophage induction. Rir and Crh were shown to form a complex in solution and Rir prevented binding of Crh to its operator sites.

Complete Genome Sequence of the Novel Virulent Phage PMBT28 with Lytic Activity against Thermotolerant Salmonella enterica subsp. enterica Serovar Senftenberg ATCC 43845.

The complete genome sequence of the novel virulent Siphoviridae phage PMBT28, which may potentially be utilized for the biocontrol of Salmonella spp., is reported here. The phage was isolated using Salmonella enterica subsp. enterica serovar Senftenberg ATCC 43845 as a bacterial host. The genome had no significant sequence similarity to known phage genomes.

Draft Genome Sequence of the Intimin-Positive Enteropathogenic Escherichia albertii Strain MBT-EA1, Isolated from Lettuce.

The genome of the intimin (eae)-harboring Escherichia albertii strain MBT-EA1, isolated from lettuce in Germany, was sequenced. Sequence analysis showed the assembled draft genome size to be 4,560,948 bp, containing a predicted total of 4,414 protein-encoding genes, 11 rRNAs, and 82 tRNAs. Furthermore, three plasmid sequences were found.

Genome Sequence of Klebsiella pneumoniae Bacteriophage PMBT1 Isolated from Raw Sewage.

A bacteriophage virulent for extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae strain 182 was isolated from sewage. The double-stranded DNA (dsDNA) genome showed high similarity to the genomes of other Klebsiella pneumoniae phages. It comprises 175,206 bp with a mol% G+C content of 41.9 and contains 276 putative open reading frames (ORFs) and one tRNA.

Draft Genome Sequence of Lactobacillus plantarum BFE 5092 Isolated from Maasai Fermented Milk.

The draft genome of Lactobacillus plantarum BFE 5092 isolated from the Maasai traditional fermented milk product kule naoto was sequenced, and sequence analysis showed the assembled genome size to be 3,285,094 bp, containing a predicted total of 3,111 protein-encoding genes, 17 rRNAs, and 70 tRNAs.

Temperate Streptococcus thermophilus phages expressing superinfection exclusion proteins of the Ltp type.

Lipoprotein Ltp encoded by temperate Streptococcus thermophilus phage TP-J34 is the prototype of the wide-spread family of host cell surface-exposed lipoproteins involved in superinfection exclusion (sie). When screening for other S. thermophilus phages expressing this type of lipoprotein, three temperate phages-TP-EW, TP-DSM20617, and TP-778-were isolated. In this communication we present the total nucleotide sequences of TP-J34 and TP-778L. For TP-EW, a phage almost identical to TP-J34, besides the ltp gene only the two regions of deviation from TP-J34 DNA were analyzed: the gene encoding the tail protein causing an assembly defect in TP-J34 and the gene encoding the lysin, which in TP-EW contains an intron. For TP-DSM20617 only the sequence of the lysogeny module containing the ltp gene was determined. The region showed high homology to the same region of TP-778. For TP-778 we could show that absence of the attR region resulted in aberrant excision of phage DNA. The amino acid sequence of mature LtpTP-EW was shown to be identical to that of mature LtpTP-J34, whereas the amino acid sequence of mature LtpTP-778 was shown to differ from mature LtpTP-J34 in eight amino acid positions. LtpTP-DSM20617 was shown to differ from LtpTP-778 in just one amino acid position. In contrast to LtpTP-J34, LtpTP-778 did not affect infection of lactococcal phage P008 instead increased activity against phage P001 was noticed.