Abstract:Lactococcus Ceduovirus (formerly c2virus) bacteriophages are among the three most prevalent phage types reported in dairy environments. Phages from this group conduct a strictly lytic lifestyle and cause substantial losses during milk fermentation processes, by infecting lactococcal host starter strains. Despite their deleterious activity, there are limited research data concerning Ceduovirus phages. To advance our knowledge on this specific phage group, we sequenced and performed a comparative analysis of 10 … Show more
“…1a ). Such halos may indicate the presence of a phage-encoded depolymerase that could eliminate exopolysaccharides in the bacterial cell wall (Chmielewska-Jeznach et al 2020 ). Fig.…”
Background
Staphylococcus arlettae
is a rarely reported coagulase-negative staphylococcus (CoNS) isolated from infected humans and livestock. Observing phage-bacteria interaction could improve the understanding of bacterial pathogenetic mechanisms, providing foundational evidence for phage therapy or phage detection. Herein, we aimed to characterise and annotate a novel bacteriophage, vB_SarS_BM31 (BM31), specific to
S. arlettae
. This bacteriophage was isolated from a milk sample associated with bovine mastitis and collected in the Sichuan Province, China.
Results
The BM31 genome comprised a linear double-stranded DNA of 42,271 base pair in length with a G + C content of 34.59%. A total of 65 open reading frames (ORFs) were assembled from phage DNA, of which 29 were functionally annotated. These functional genes were divided into four modules: the structural, DNA packing and replication, lysis, and lysogeny modules. Holin (ORF25), lysin (ORF26), and integrase (ORF28) were located closely in the entire BM31 genome and were important for lyse or lysogeny cycle of BM31. The phage was identified as a temperate phage according to whole genome analysis and life cycle assay, with basic biological characteristics such as small burst size, short latency period, and narrow host range, consistent with the characteristics of the family Siphoviridae, subcluster B14 of the
Staphylococcus
bacteriophage.
Conclusions
The present isolation and characterisation of BM31 contributes to the
Staphylococcus
bacteriophage database and provides a theoretical foundation for its potential applications. To the best of our knowledge, BM31 is the only shared and completely reported phage against
S. arlettae
in the entire public database.
Supplementary Information
The online version contains supplementary material available at 10.1007/s10123-022-00292-3.
“…1a ). Such halos may indicate the presence of a phage-encoded depolymerase that could eliminate exopolysaccharides in the bacterial cell wall (Chmielewska-Jeznach et al 2020 ). Fig.…”
Background
Staphylococcus arlettae
is a rarely reported coagulase-negative staphylococcus (CoNS) isolated from infected humans and livestock. Observing phage-bacteria interaction could improve the understanding of bacterial pathogenetic mechanisms, providing foundational evidence for phage therapy or phage detection. Herein, we aimed to characterise and annotate a novel bacteriophage, vB_SarS_BM31 (BM31), specific to
S. arlettae
. This bacteriophage was isolated from a milk sample associated with bovine mastitis and collected in the Sichuan Province, China.
Results
The BM31 genome comprised a linear double-stranded DNA of 42,271 base pair in length with a G + C content of 34.59%. A total of 65 open reading frames (ORFs) were assembled from phage DNA, of which 29 were functionally annotated. These functional genes were divided into four modules: the structural, DNA packing and replication, lysis, and lysogeny modules. Holin (ORF25), lysin (ORF26), and integrase (ORF28) were located closely in the entire BM31 genome and were important for lyse or lysogeny cycle of BM31. The phage was identified as a temperate phage according to whole genome analysis and life cycle assay, with basic biological characteristics such as small burst size, short latency period, and narrow host range, consistent with the characteristics of the family Siphoviridae, subcluster B14 of the
Staphylococcus
bacteriophage.
Conclusions
The present isolation and characterisation of BM31 contributes to the
Staphylococcus
bacteriophage database and provides a theoretical foundation for its potential applications. To the best of our knowledge, BM31 is the only shared and completely reported phage against
S. arlettae
in the entire public database.
Supplementary Information
The online version contains supplementary material available at 10.1007/s10123-022-00292-3.
“…The burst size (pfu per infected cell) was calculated as phage titer at the end of the one-step growth curve minus the initial titer and divided by the initial titer. The latent period was defined at the starting of the exponential phase and the burst time as the time invested to complete one cycle (Chmielewska-Jeznach et al, 2020).…”
Bacteriophages are a nuisance in the production of fermented dairy products driven by starter bacteria and strategies to reduce the risk of phage infection are permanently sought. Bearing in mind that the bacterial cell wall plays a pivotal role in host recognition and lysis, our goal was to elucidate to which extent modifications in the cell wall may alter endolysin activity and influence the outcome of phage infection in Lactococcus. Three lactococcal endolysins with distinct catalytic domains (CHAP, amidase and lysozyme) from phages 1,358, p2 and c2 respectively, were purified and their exolytic activity was tested against lactococcal mutants either overexpressing or lacking genes involved in the cell envelope stress (CES) response or in modifying peptidoglycan (PG) composition. After recombinant production in E. coli, Lys1358 (CHAP) and LysC2 (muramidase) were able to lyse lactococcal cells in turbidity reduction assays, but no activity of LysP2 was detected. The degree of PG acetylation, namely C6-O-acetylation and de-N-acetylation influenced the exolytic activity, being LysC2 more active against cells depleted of the PG deacetylase PgdA and the O-acetyl transferase OatA. On the contrary, both endolysins showed reduced activity on cells with an induced CES response. By measuring several growth parameters of phage c2 on these lactococcal mutants (lytic score, efficiency of plaquing, plaque size and one-step curves), a direct link between the exolytic activity of its endolysin and phage performance could not be stablished.
“…Through fluorescence binding assays, the CBMs of the NPS and TpeX have been determined to exhibit the same host specificity as the RBP (though with inferior affinity when compared to that of the RBP) and bind favourably towards the ends of the cell where cell division occurs [26] . Certain P335 phages also have an additional CBM located in an auxiliary binding protein known as the BppA [45,60] . Most lactococcal and streptococcal phages encode a Dit, which is either classified as classical or evolved.…”
Section: Recognition Of Saccharidic Receptorsmentioning
confidence: 99%
“…The interactions between lactococcal and streptococcal phages and their cognate host have been the focus of intense research scrutiny over the past three decades [ 56 , 59 - 61 ] . The majority of streptococcal and lactococcal phages recognise saccharidic receptors: exopolysaccharide (EPS) or rhamnose-glucose polysaccharide (RGP), and cell wall polysaccharide structures (CWPS), respectively [ 56 , 62 ] .…”
Food fermentation relies on the activity of robust starter cultures, which are commonly comprised of lactic acid bacteria such as Lactococcus and Streptococcus thermophilus. While bacteriophage infection represents a persistent threat that may cause slowed or failed fermentations, their beneficial role in fermentations is also being appreciated. In order to develop robust starter cultures, it is important to understand how phages interact with and modulate the compositional landscape of these complex microbial communities. Both culture-dependent and -independent methods have been instrumental in defining individual phage-host interactions of many lactic acid bacteria (LAB). This knowledge needs to be integrated and expanded to obtain a full understanding of the overall complexity of such interactions pertinent to fermented foods through a combination of culturomics, metagenomics, and phageomics. With such knowledge, it is believed that factory-specific detection and monitoring systems may be developed to ensure robust and reliable fermentation practices. In this review, we explore/discuss phage-host interactions of LAB, the role of both virulent and temperate phages on the microbial composition, and the current knowledge of phageomes of fermented foods.
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