scholarly journals Streptococcus thermophilus Is Able To Produce a β-Galactosidase Active during Its Transit in the Digestive Tract of Germ-Free Mice

2002 ◽  
Vol 68 (2) ◽  
pp. 938-941 ◽  
Author(s):  
Sophie Drouault ◽  
Jamila Anba ◽  
G�rard Corthier
Keyword(s):  
Gene Expression ◽  
Digestive Tract ◽  
Streptococcus Thermophilus ◽  
Bacterial Luciferase ◽  
Germ Free

ABSTRACT This work presents data on the application of a bacterial luciferase used to monitor gene expression of Streptococcus thermophilus in the digestive tract. The main result is that the bacterium was able to produce an active β-galactosidase in the digestive tract, although it did not multiply during its transit. This production was enhanced when lactose (the inducer) was added to the diet.

scholarly journals Use of Luciferase Genes as Biosensors To Study Bacterial Physiology in the Digestive Tract

1998 ◽  
Vol 64 (7) ◽  
pp. 2721-2722 ◽  
Author(s):  
G. Corthier ◽  
C. Delorme ◽  
S. D. Ehrlich ◽  
P. Renault
Keyword(s):  
Gene Expression ◽  
Digestive Tract ◽  
Lactococcus Lactis ◽  
Promoter Strength ◽  
Bacterial Luciferase ◽  
Bacterial Physiology ◽  
Different Strains ◽  
Transcriptional Fusions

ABSTRACT A method based on the use of the bacterial luciferase genes was developed in order to investigate Lactococcus lactis gene expression in the mouse digestive tract. Germfree mice were monoassociated with different strains containing transcriptional fusions of promoters with the luciferase genes. Our results demonstrate that this method is readily applicable to the study of promoter strength and physiology of bacteria in the digestive tract.

scholarly journals Analysis of the Genetic Switch and Replication Region of a P335-Type Bacteriophage with an Obligate Lytic Lifestyle onLactococcus lactis

2001 ◽  
Vol 67 (3) ◽  
pp. 1128-1139 ◽  
Author(s):  
Søren M. Madsen ◽  
David Mills ◽  
Gordana Djordjevic ◽  
Hans Israelsen ◽  
Todd R. Klaenhammer
Keyword(s):  
Gene Expression ◽  
Attachment Site ◽  
Streptococcus Thermophilus ◽  
Regulatory Elements ◽  
Lytic Phage ◽  
Genetic Switch ◽  
Integrase Gene ◽  
Replication Module ◽  
Gene Homologue ◽  
I Gene

ABSTRACT The DNA sequence of the replication module, part of the lysis module, and remnants of a lysogenic module from the lytic P335 species lactococcal bacteriophage φ31 was determined, and its regulatory elements were investigated. The identification of a characteristic genetic switch including two divergent promoters and two cognate repressor genes strongly indicates that φ31 was derived from a temperate bacteriophage. Regulation of the two early promoters was analyzed by primer extension and transcriptional promoter fusions to a lacLMreporter. The regulatory behavior of the promoter region differed significantly from the genetic responses of temperate Lactococcus lactis phages. Thecro gene homologue regulates its own production and is an efficient repressor of cI gene expression. No detectablecI gene expression could be measured in the presence ofcro. cI gene expression in the absence ofcro exerted minor influences on the regulation of the two promoters within the genetic switch. Homology comparisons revealed a replication module which is most likely expressed from the promoter located upstream of the cro gene homologue. The replication module encoded genes with strong homology to helicases and primases found in several Streptococcus thermophilus phages. Downstream of the primase homologue, an AT-rich noncoding origin region was identified. The characteristics and location of this region and its ability to reduce the efficiency of plaquing of φ31 106-fold when present at high copy number in trans provide evidence for identification of the phage origin of replication. Phage φ31 is an obligately lytic phage that was isolated from commercial dairy fermentation environments. Neither a phage attachment site nor an integrase gene, required to establish lysogeny, was identified, explaining its lytic lifestyle and suggesting its origin from a temperate phage ancestor. Several regions showing extensive DNA and protein homologies to different temperate phages ofLactococcus, Lactobacillus, andStreptococcus were also discovered, indicating the likely exchange of DNA cassettes through horizontal gene transfer in the dynamic ecological environment of dairy fermentations.

scholarly journals Establishing Probiotic Saccharomyces boulardii as a Model Organism for Synthesis and Delivery of Biomolecules

2020 ◽  
Author(s):  
Deniz Durmusoglu ◽  
Ibrahim Al’Abri ◽  
Scott P. Collins ◽  
Chase Beisel ◽  
Nathan Crook
Keyword(s):  
Gene Expression ◽  
Copy Number ◽  
Model Organism ◽  
Saccharomyces Boulardii ◽  
Gastrointestinal Disorders ◽  
Control Of Gene Expression ◽  
Germ Free ◽  
Gut Colonization ◽  
Wide Range ◽  
Dosing Strategy

AbstractSaccharomyces boulardii is a widely used yeast probiotic which can counteract various gastrointestinal disorders1. As a relative of Saccharomyces cerevisiae, S. boulardii exhibits rapid growth and is easy to transform2 and thus represents a promising chassis for the engineered secretion of biomolecules. To establish S. boulardii as a platform for delivery of biomolecules to the mammalian gut, we measured the amount and variance in protein expression enabled by promoters, terminators, selective markers, and copy number control elements in this organism. These genetic elements were characterized in plasmidic and genomic contexts, revealing strategies for tunable control of gene expression and CRISPR-mediated genome editing in this strain. We then leveraged this set of genetic parts to combinatorially assemble pathways enabling a wide range of drug and vitamin titers. Finally, we measured S. boulardii’s residence time in the gastrointestinal tracts of germ-free and antibiotic-treated mice, revealing the relationships between dosing strategy and colonization level. This work establishes S. boulardii as a genetically tractable commensal fungus and provides a set of strategies for engineering S. boulardii to synthesize and deliver biomolecules during gut colonization.

scholarly journals Molecular genetics in Streptococcus thermophilus: from transformation to gene expression

1993 ◽  
Vol 73 (2) ◽  
pp. 175-180 ◽  
Author(s):  
B. Mollet ◽  
A. Constable ◽  
M. Delley ◽  
J. Knol ◽  
O. Marciset ◽  
...  
Keyword(s):  
Gene Expression ◽  
Molecular Genetics ◽  
Streptococcus Thermophilus

Gene Expression Analysis of the Enteric Nervous System in Germ Free Mice

2011 ◽  
Vol 140 (5) ◽  
pp. S-522
Author(s):  
Subhash Kulkarni ◽  
Laren Becker ◽  
Gunjan Tiwari ◽  
Johann Peterson ◽  
Maria-Adelaide Micci ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nervous System ◽  
Enteric Nervous System ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Germ Free

scholarly journals Carbohydrate Metabolism Is Essential for the Colonization of Streptococcus thermophilus in the Digestive Tract of Gnotobiotic Rats

PLoS ONE ◽  
2011 ◽  
Vol 6 (12) ◽  
pp. e28789 ◽  
Author(s):  
Muriel Thomas ◽  
Laura Wrzosek ◽  
Leila Ben-Yahia ◽  
Marie-Louise Noordine ◽  
Christophe Gitton ◽  
...  
Keyword(s):  
Carbohydrate Metabolism ◽  
Digestive Tract ◽  
Streptococcus Thermophilus

scholarly journals Specific Establishment of Lactobacilli in the Digestive Tract of Germ-Free Chickens

1971 ◽  
Vol 15 (6) ◽  
pp. 531-538 ◽  
Author(s):  
Yoshiyuki Morishita ◽  
Tomotari Mitsuoka ◽  
Choji Kaneuchi ◽  
Shutaro Yamamoto ◽  
Manabu Ogata
Keyword(s):  
Digestive Tract ◽  
Germ Free
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