scholarly journals Characterization of a Novel Integrative Element, ICESt1, in the Lactic Acid BacteriumStreptococcus thermophilus

2000 ◽  
Vol 66 (4) ◽  
pp. 1749-1753 ◽  
Author(s):  
Vincent Burrus ◽  
Yvonne Roussel ◽  
Bernard Decaris ◽  
Gérard Guédon
Keyword(s):  
Lactic Acid ◽  
Streptococcus Thermophilus ◽  
Conjugative Transfer ◽  
Gene Encoding ◽  
Conjugative Transposon ◽  
Site Specific ◽  
Conjugative Transposons ◽  
Integrative Conjugative Element ◽  
A Site

ABSTRACT The 35.5-kb ICESt1 element of Streptococcus thermophilus CNRZ368 is bordered by a 27-bp repeat and integrated into the 3′ end of a gene encoding a putative fructose-1,6-biphosphate aldolase. This element encodes site-specific integrase and excisionase enzymes related to those of conjugative transposons Tn5276and Tn5252. The integrase was found to be involved in a site-specific excision of a circular form. ICESt1 also encodes putative conjugative transfer proteins related to those of the conjugative transposon Tn916. Therefore, ICESt1could be or could be derived from an integrative conjugative element.

scholarly journals Conjugative Transfer of the Integrative Conjugative Elements ICESt1 and ICESt3 from Streptococcus thermophilus

2009 ◽  
Vol 191 (8) ◽  
pp. 2764-2775 ◽  
Author(s):  
Xavier Bellanger ◽  
Adam P. Roberts ◽  
Catherine Morel ◽  
Frédéric Choulet ◽  
Guillaume Pavlovic ◽  
...  
Keyword(s):  
Streptococcus Thermophilus ◽  
Genomic Islands ◽  
Conjugative Transfer ◽  
Integrase Gene ◽  
Site Specific ◽  
Integrative And Conjugative Elements ◽  
Conjugative Transposons ◽  
Site Specific Integration ◽  
The One ◽  
Integrative Conjugative Elements

ABSTRACT Integrative and conjugative elements (ICEs), also called conjugative transposons, are genomic islands that excise, self-transfer by conjugation, and integrate in the genome of the recipient bacterium. The current investigation shows the intraspecies conjugative transfer of the first described ICEs in Streptococcus thermophilus, ICESt1 and ICESt3. Mitomycin C, a DNA-damaging agent, derepresses ICESt3 conjugative transfer almost 25-fold. The ICESt3 host range was determined using various members of the Firmicutes as recipients. Whereas numerous ICESt3 transconjugants of Streptococcus pyogenes and Enterococcus faecalis were recovered, only one transconjugant of Lactococcus lactis was obtained. The newly incoming ICEs, except the one from L. lactis, are site-specifically integrated into the 3′ end of the fda gene and are still able to excise in these transconjugants. Furthermore, ICESt3 was retransferred from E. faecalis to S. thermophilus. Recombinant plasmids carrying different parts of the ICESt1 recombination module were used to show that the integrase gene is required for the site-specific integration and excision of the ICEs, whereas the excisionase gene is required for the site-specific excision only.

scholarly journals Phase Variation of Campylobacter jejuni 81-176 Lipooligosaccharide Affects Ganglioside Mimicry and Invasiveness In Vitro

2002 ◽  
Vol 70 (2) ◽  
pp. 787-793 ◽  
Author(s):  
Patricia Guerry ◽  
Christine M. Szymanski ◽  
Martina M. Prendergast ◽  
Thomas E. Hickey ◽  
Cheryl P. Ewing ◽  
...  
Keyword(s):  
Campylobacter Jejuni ◽  
Phase Variation ◽  
Outer Core ◽  
Gene Encoding ◽  
Site Specific ◽  
Reading Frame ◽  
Specific Mutation ◽  
Normal Human ◽  
A Site

ABSTRACT The outer cores of the lipooligosaccharides (LOS) of many strains of Campylobacter jejuni mimic human gangliosides in structure. A population of cells of C. jejuni strain 81-176 produced a mixture of LOS cores which consisted primarily of structures mimicking GM2 and GM3 gangliosides, with minor amounts of structures mimicking GD1b and GD2. Genetic analyses of genes involved in the biosynthesis of the outer core of C. jejuni 81-176 revealed the presence of a homopolymeric tract of G residues within a gene encoding CgtA, an N-acetylgalactosaminyltransferase. Variation in the number of G residues within cgtA affected the length of the open reading frame, and these changes in cgtA corresponded to a change in LOS structure from GM2 to GM3 ganglioside mimicry. Site-specific mutation of cgtA in 81-176 resulted in a major LOS core structure that lacked GalNAc and resembled GM3 ganglioside. Compared to wild-type 81-176, the cgtA mutant showed a significant increase in invasion of INT407 cells. In comparison, a site-specific mutation of the neuC1 gene resulted in the loss of sialic acid in the LOS core and reduced resistance to normal human serum but had no affect on invasion of INT407 cells.

scholarly journals Purification and Characterization of the R64 Shufflon-Specific Recombinase

2000 ◽  
Vol 182 (10) ◽  
pp. 2787-2792 ◽  
Author(s):  
Atsuko Gyohda ◽  
Teruya Komano
Keyword(s):  
Electrophoretic Analysis ◽  
Recombination Reaction ◽  
Site Specific ◽  
Dna Inversion ◽  
Repeat Sequences ◽  
In Vitro Recombination ◽  
Recombinase Gene ◽  
A Site

ABSTRACT The shufflon, a multiple DNA inversion system in plasmid R64, consists of four invertible DNA segments which are separated and flanked by seven 19-bp repeat sequences. The product of a site-specific recombinase gene, rci, promotes site-specific recombination between any two of the inverted 19-bp repeat sequences of the shufflon. To analyze the molecular mechanism of this recombination reaction, Rci protein was overproduced and purified. The purified Rci protein promoted the in vitro recombination reaction between the inverted 19-bp repeats of supercoiled DNA of a plasmid carrying segment A of the R64 shufflon. The recombination reaction was enhanced by the bacterial host factor HU. Gel electrophoretic analysis indicated that the Rci protein specifically binds to the DNA segments carrying the 19-bp sequences. The binding affinity of the Rci protein to the four shufflon segments as well as four synthetic 19-bp sequences differed greatly: among the four 19-bp repeat sequences, the repeat-a and -d sequences displayed higher affinity to Rci protein. These results suggest that the differences in the affinity of Rci protein for the 19-bp repeat sequences determine the inversion frequencies of the four segments.

Characterization of deoxyribozymes with site-specific oxidative cleavage activity against DNA obtained by in vitro selection

2016 ◽  
Vol 14 (7) ◽  
pp. 2347-2351 ◽  
Author(s):  
Ming-Qi Wang ◽  
Juan Dong ◽  
Huafan Zhang ◽  
Zhuo Tang
Keyword(s):  
In Vitro Selection ◽  
Oxidative Cleavage ◽  
Site Specific ◽  
New Class ◽  
Cleavage Activity ◽  
A Site

We have generated a new class of deoxyribozymes that required Mn2+ and Cu2+ to catalyze a site-specific oxidative cleavage of DNA.

Characterization of the lactic acid bacteria in artisanal dairy products

1997 ◽  
Vol 64 (3) ◽  
pp. 409-421 ◽  
Author(s):  
TIMOTHY M. COGAN ◽  
MANUELA BARBOSA ◽  
ERIC BEUVIER ◽  
BRUNA BIANCHI-SALVADORI ◽  
PIER S. COCCONCELLI ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Broad Spectrum ◽  
Acid Production ◽  
Dairy Products ◽  
Streptococcus Thermophilus ◽  
Listeria Innocua

In all, 4379 isolates from 35 products, including 24 artisanal cheeses, were surveyed with a view to identifying strains that could be used as starters in commercial dairy fermentations. Of the isolates, 38% were classified as Lactococcus, 17% as Enterococcus, 14% as Streptococcus thermophilus, 12% as mesophilic Lactobacillus, 10% as Leuconostoc and 9% as thermophilic Lactobacillus. Acid production by the isolates varied considerably. Of the 1582 isolates of Lactococcus and 482 isolates of mesophilic Lactobacillus tested, only 8 and 2% respectively produced sufficient acid to lower the pH of milk to <5·3 in 6 h at 30°C. In contrast, 53, 32 and 13% of Str. thermophilus, thermophilic Lactobacillus and Enterococcus isolates respectively reduced the pH to 5·3. These isolates were found only in some French, Italian and Greek cheeses. Bacteriocins were produced by 11% of the 2257 isolates tested and 26 of them produced broad-spectrum bacteriocins which inhibited at least eight of the ten target strains used, which included lactic acid bacteria, clostridia and Listeria innocua. The most proteolytic of the 2469 isolates tested were Str. thermophilus from Fontina cheese followed by Enterococcus from Fiore Sardo and Toma cheese and thermophilic Lactobacillus from all sources. Exopolysaccharides were produced by 5·3% of the 2224 isolates tested.

Applications of CRISPR-Cas systems in lactic acid bacteria

2020 ◽  
Vol 44 (5) ◽  
pp. 523-537 ◽  
Author(s):  
Avery Roberts ◽  
Rodolphe Barrangou
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Streptococcus Thermophilus ◽  
Starter Cultures ◽  
Natural Environments ◽  
Gene Therapies ◽  
The Past ◽  
Food And Agriculture ◽  
Functionally Diverse

ABSTRACT As a phenotypically and phylogenetically diverse group, lactic acid bacteria are found in a variety of natural environments and occupy important roles in medicine, biotechnology, food and agriculture. The widespread use of lactic acid bacteria across these industries fuels the need for new and functionally diverse strains that may be utilized as starter cultures or probiotics. Originally characterized in lactic acid bacteria, CRISPR-Cas systems and derived molecular machines can be used natively or exogenously to engineer new strains with enhanced functional attributes. Research on CRISPR-Cas biology and its applications has exploded over the past decade with studies spanning from the initial characterization of CRISPR-Cas immunity in Streptococcus thermophilus to the use of CRISPR-Cas for clinical gene therapies. Here, we discuss CRISPR-Cas classification, overview CRISPR biology and mechanism of action, and discuss current and future applications in lactic acid bacteria, opening new avenues for their industrial exploitation and manipulation of microbiomes.

Preparation and characterization of a viral DNA molecule containing a site-specific 2-aminofluorene adduct: A new probe for mutagenesis by carcinogens

Biochemistry ◽  
1986 ◽  
Vol 25 (2) ◽  
pp. 449-456 ◽  
Author(s):  
Dana L. Johnson ◽  
Thomas M. Reid ◽  
Mei-Sie Lee ◽  
Charles M. King ◽  
Louis J. Romano
Keyword(s):  
Viral Dna ◽  
Site Specific ◽  
Dna Molecule ◽  
A Site

scholarly journals Characterization of a Novel Type II Restriction-Modification System, Sth368I, Encoded by the Integrative Element ICESt1 of Streptococcus thermophilusCNRZ368

2001 ◽  
Vol 67 (4) ◽  
pp. 1522-1528 ◽  
Author(s):  
Vincent Burrus ◽  
Cyril Bontemps ◽  
Bernard Decaris ◽  
Gérard Guédon
Keyword(s):  
Protein Sequence ◽  
Streptococcus Thermophilus ◽  
Type Ii ◽  
Modification System ◽  
Restriction Modification System ◽  
Integrative Conjugative Element ◽  
Cell Extracts ◽  
Numerous Type ◽  
Gatc Site

ABSTRACT A novel type II restriction and modification (R-M) system,Sth368I, which confers resistance to φST84, was found inStreptococcus thermophilus CNRZ368 but not in the very closely related strain A054. Partial sequencing of the integrative conjugative element ICESt1, carried by S. thermophilus CNRZ368 but not by A054, revealed a divergent cluster of two genes, sth368IR and sth368IM. The protein sequence encoded by sth368IR is related to the type II endonucleases R.LlaKR2I and R.Sau3AI, which recognize and cleave the sequence 5′-GATC-3′. The protein sequence encoded by sth368IM is very similar to numerous type II 5-methylcytosine methyltransferases, including M.LlaKR2I and M.Sau3AI. Cell extracts of CNRZ368 but not A054 were found to cleave at the GATC site. Furthermore, the C residue of the sequence 5′-GATC-3′ was found to be methylated in CNRZ368 but not in A054. Cloning and integration of a copy of sth368IR and sth368IMin the A054 chromosome confers on this strain phenotypes similar to those of CNRZ368, i.e., phage resistance, endonuclease activity of cell extracts, and methylation of the sequence 5′-GATC-3′. Disruption of sth368IR removes resistance and restriction activity. We conclude that ICESt1 encodes an R-M system, Sth368I, which recognizes the sequence 5′-GATC-3′ and is related to the Sau3AI and LlaKR2I restriction systems.

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