scholarly journals Biodiversity of Streptococcus thermophilus Phages in Global Dairy Fermentations

Viruses ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 577 ◽  
Author(s):  
Katherine Lavelle ◽  
Ines Martinez ◽  
Horst Neve ◽  
Gabriele Lugli ◽  
Charles Franz ◽  
...  
Keyword(s):  
Host Range ◽  
Fragment Length Polymorphism ◽  
Sequence Similarity ◽  
Streptococcus Thermophilus ◽  
Starter Cultures ◽  
Polymorphism Analysis ◽  
Phage Group ◽  
Protein Phylogeny ◽  
Dairy Fermentation ◽  
Receptor Binding Protein

Streptococcus thermophilus strains are among the most widely employed starter cultures in dairy fermentations, second only to those of Lactococcus lactis. The extensive application of this species provides considerable opportunity for the proliferation of its infecting (bacterio)phages. Until recently, dairy streptococcal phages were classified into two groups (cos and pac groups), while more recently, two additional groups have been identified (5093 and 987 groups). This highlights the requirement for consistent monitoring of phage populations in the industry. Here, we report a survey of 35 samples of whey derived from 27 dairy fermentation facilities in ten countries against a panel of S. thermophilus strains. This culminated in the identification of 172 plaque isolates, which were characterized by multiplex PCR, restriction fragment length polymorphism analysis, and host range profiling. Based on this characterisation, 39 distinct isolates representing all four phage groups were selected for genome sequencing. Genetic diversity was observed among the cos isolates and correlations between receptor binding protein phylogeny and host range were also clear within this phage group. The 987 phages isolated within this study shared high levels of sequence similarity, yet displayed reduced levels of similarity to those identified in previous studies, indicating that they are subject to ongoing genetic diversification.

scholarly journals Identification of the Receptor-Binding Protein in Lytic Leuconostoc pseudomesenteroides Bacteriophages

2013 ◽  
Vol 79 (10) ◽  
pp. 3311-3314 ◽  
Author(s):  
Witold Kot ◽  
Karin Hammer ◽  
Horst Neve ◽  
Finn K. Vogensen
Keyword(s):  
Nucleotide Sequence ◽  
Host Range ◽  
Receptor Binding ◽  
Nucleotide Sequence Identity ◽  
Sequence Similarity ◽  
Content Type ◽  
Sequence Identity ◽  
Different Strains ◽  
Leuconostoc Pseudomesenteroides ◽  
Receptor Binding Protein

ABSTRACTTwo phages, P793 and ΦLN04, sharing 80.1% nucleotide sequence identity but having different strains ofLeuconostoc pseudomesenteroidesas hosts, were selected for identification of the host determinant gene. Construction of chimeric phages leading to the expected switch in host range identified the host determinant genes as ORF21P793/ORF23ΦLN04. The genes are located in the tail structural module and have low sequence similarity at the distal end.

scholarly journals Phytoplasma occurrence in apple trees in the Czech Republic

2011 ◽  
Vol 39 (No. 1) ◽  
pp. 7-12 ◽  
Author(s):  
R. Fialová ◽  
M. Navrátil ◽  
P. Válová
Keyword(s):  
Fragment Length Polymorphism ◽  
Rrna Gene ◽  
Polymorphism Analysis ◽  
Apple Proliferation ◽  
Chain Reaction ◽  
Apple Trees ◽  
The Czech Republic ◽  
High Incidence ◽  
Phytoplasma Infection ◽  
Polymerase Chain

The presence of phytoplasmas in apple trees with proliferation symptoms, rubbery wood symptoms and no symp­toms was determined by using polymerase chain reaction assays with primers amplifying phytoplasma 16S rRNA gene. Phytoplasmas were detected in all trees with proliferation symptoms. Positive tests for phytoplasma in the group of trees with rubbery wood symptoms and of those without symptoms revealed a relatively high incidence of latent phytoplasma infection. Using restriction fragment length polymorphism analysis, phytoplasma of the same identity – apple proliferation phytoplasma (subgroup 16SrX-A) – was recorded in all positively tested trees.  

Systematic evidence from gene duplication and regulation

1990 ◽  
Vol 3 (1) ◽  
pp. 145
Author(s):  
DJ Colgan
Keyword(s):  
Gene Duplication ◽  
Evolutionary History ◽  
Tandem Duplication ◽  
Fragment Length Polymorphism ◽  
Duplicate Genes ◽  
Polymorphism Analysis ◽  
Multiple Origins ◽  
The Family ◽  
History Of ◽  
Phylogenetic Hypotheses

This paper is a review of the use of information regarding the presence of duplicate genes and their regulation in systematics. The review concentrates on data derived from protein electrophoresis and restriction fragment length polymorphism analysis. The appearance of a duplication in a subset of a group of species implies that the members of the subset belong to the same clade. Suppression of the duplication may render this clade apparently paraphyletic, but may itself be informative of relations within the lineage through patterns of loss of expression in all, or some tissues, or through restrictions of the formation of functional heteropolymers in polymeric enzymes. Examples are given of studies which have used such information to establish phylogenetic hypotheses at the family level, to identify an auto- or allo-polyploid origin of polyploid species and to determine whether there have been single or multiple origins of such species. The likelihood of homoplasy in the patterns of appearance and regulation of duplicates depends on the molecular basis of the duplication. In particular, the contrast between the expected consequences of tandem duplication and the expression of pseudogenes emphasises the value of determining the mechanism of the original duplication. Many instances of sporadic gene duplication are now known, and polyploidisation is a common event in the evolutionary history of both plants and animals. So the opportunities to discover duplicationrelated characters will arise in many systematic studies. A program is presented to increase the chances that such useful information will be recognisable during the studies.

scholarly journals Structure of the Chromosome VII Centromere Region in Neurospora crassa: Degenerate Transposons and Simple Repeats

1998 ◽  
Vol 18 (9) ◽  
pp. 5465-5477 ◽  
Author(s):  
Edward B. Cambareri ◽  
Rafael Aisner ◽  
John Carbon
Keyword(s):  
Neurospora Crassa ◽  
Yeast Artificial Chromosome ◽  
Fragment Length Polymorphism ◽  
Artificial Chromosome ◽  
Polymorphism Analysis ◽  
Dna Repeats ◽  
Centromere Region ◽  
Simple Repeats ◽  
Restriction Fragment Length ◽  
Repeat Induced Point Mutation

ABSTRACT DNA from the centromere region of linkage group (LG) VII ofNeurospora crassa was cloned previously from a yeast artificial chromosome library and was found to be atypical ofNeurospora DNA in both composition (AT rich) and complexity (repetitive). We have determined the DNA sequence of a small portion (∼16.1 kb) of this region and have identified a cluster of three new retrotransposon-like elements as well as degenerate fragments from the 3′ end of Tad, a previously identified LINE-like retrotransposon. This region contains a novel full-length but nonmobilecopia-like element, designated Tcen, that is only associated with centromere regions. Adjacent DNA contains portions of a gypsy-like element designated Tgl1. A third new element, Tgl2, shows similarity to theTy3 transposon of Saccharomyces cerevisiae. All three of these elements appear to be degenerate, containing predominantly transition mutations suggestive of the repeat-induced point mutation (RIP) process. Three new simple DNA repeats have also been identified in the LG VII centromere region. While Tcenelements map exclusively to centromere regions by restriction fragment length polymorphism analysis, the defective Tad elements appear to occur most frequently within centromeres but are also found at other loci including telomeres. The characteristics and arrangement of these elements are similar to those seen in theDrosophila centromere, but the relative abundance of each class of repeats, as well as the sequence degeneracy of the transposon-like elements, is unique to Neurospora. These results suggest that the Neurospora centromere is heterochromatic and regional in character, more similar to centromeres of Drosophila than to those of most single-cell yeasts.

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