Phage and antibiotic in raw milk poses significant risks for starter culture activity in fermented products. Therefore, rapid detection of phage and antibiotic contaminations in raw milk is a crucial process in dairy science. For this purpose, a preliminary novel method for detection of phage and antibiotic was developed by using Raman spectroscopy. phages and ampicillin which are quite important elements in dairy industry were used as model. The phage and antibiotic samples were added to raw milk separately, and Raman measurements were carried out. The obtained spectra were processed with a chemometric method. In this study, it has been demonstrated that the presence of phage has a titer sufficient to stop the fermentation (10 pfu/ml), and antibiotic in a concentration which inhibits the growth of starter cultures (0.5 µg/ml) in raw milk could be discriminated through Raman spectroscopy with a short analysis time (30 min).
Nowadays, resistance in pathogens against antibiotics is one of the most critical health-threatening problems in the world. Therefore, finding new treatment methods to be used as an alternative to antibiotics has become a priority for researchers. Like phages, certain products containing antimicrobial components such as molasses are widely used to eliminate resistant bacteria. Molasses has a strong antimicrobial effect on the bacterial cell, and this effect is thought to be due to the breakdown of the cytoplasmic cell membrane and cell proteins of the polyphenols in molasses. In the present study, phages-molasses interactions were investigated to examine the effects arising from concomitant use. It was found that molasses samples increased the size of phage plaques by up to 3-fold, and MIC and 1/2×MIC concentration of molasses increased the burst size of phages. Although no synergistic effect was found between the phage and the molasses, the antimicrobial activities of the components and the effect of molasses on phage activity were demonstrated.
In this study, 26 Streptococcus thermophilus phages were classified according to their structural protein patterns and DNA restriction fragment length polymorphism. Furthermore, sensitivities of natural and commercial S. thermophilus strains to S. thermophilus phages were investigated. All the natural strains were found to be resistant to the phages. The electrophoretic profiles of the structural proteins of S. thermophilus phages were identified according to the two common major bands at 30.6 and 27.3 kDa. Various restriction endonucleases were used to digest S. thermophilus phages that were differentiated into eight subgroups depending on the length of EcoRV digestion. A phylogenetic tree was designed using fragments of EcoRV digestion. The results showed that all phages derived from a common ancestor and some of them were differentiated from each other over time.
PRACTICAL APPLICATIONSLike other microorganisms, it is necessary to identify and classify the phages in order to follow their evolutionary development. Besides, the characterization of these phages is also important for determining the rotation program of the culture in dairy factory. In this study, the phages isolated from different dairy products were identified and classified according to their properties.
ÖzetBu çal›flmada, daha önce yap›lm›fl çal›flmalarla morfolojik olarak tan›mlanm›fl, konakç› spektrumu ve yap›sal proteinleri belirlenmifl, restriksiyon fragment analizleri yap›lm›fl 231-X10 faj›n›n belirli bir genom bölgesinin dizi analizi yap›lm›flt›r. Dizi analizi yap›lm›fl olan bu bölgede 13 adet aç›k okuma çerçevesinin yani 13 farkl› fonksiyonu kodlayan gen bölgesinin olabilece¤i ortaya ç›kar›lm›flt›r. Bu gen bölgelerinin faj DNA's›n›n replikasyonu, DNA'n›n paketlenmesi, kapsid ve kuyruk yap›s›n›n oluflumundan sorumlu proteinleri kodlad›¤› belirlenmifltir. 231-X10 faj›na ait bu genom bölgesi taraf›ndan kodlanan proteinlerin aminoasit baz›nda cos-tipi DNA paketleme mekanizmas›na sahip fajlarla yüksek benzerlik gösterdi¤i tespit edilmifl ve dolay›s›yla bu faj›n da cos-tipi olabilece¤i sonucuna var›lm›flt›r. Yap›lan bu incelemeler sonucunda S. thermophilus fajlar›n›n ortak bir atadan geldi¤i, nokta mutasyonlar, küçük eklemeler ve kay›plar ile evrimlefltikleri düflüncesi desteklenmifltir.
Anahtar kelimeler: S. thermophilus faj›, dizi analizi, genomik organizasyon
PARTIAL GENOMIC CHARACTERIZATION OF STREPTOCOCCUS THERMOPHILUS PHAGE 231-X10 AbstractIn this study, the partial genomic sequencing of S. thermophilus 231-X10 phage was carried out. 231-X10 was identified morphologically, and its host spectrum, structural proteins and restriction analysis have also been completed in previous studies. Thirteen different open reading frames that was coded by thirteen genes were detected in that partial genome. These genes are responsible for DNA replication, DNA packaging and the formation of capsid and tail structure. The proteins that are encoded by the genomic region of 231-X10 phage have been found to show high similarities between the phages which have cos-type DNA packaging mechanism on the basis of amino acids. Thus, it is concluded that the 231-X10 phage might also be cos-type. As a result of these investigations, it is supported the idea that S. thermophilus phages come from a common ancestor and evolved with point mutations, small additions and deletions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.