A note on lactobacilli and β‐glucuronidase activity in the intestinal contents of mice

McConnell, Michelle; Tannock, Gerald W.

doi:10.1111/j.1365-2672.1993.tb05198.x

Cited by 26 publications

(12 citation statements)

References 11 publications

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“…Previous studies have observed ␤-glucuronidase activity in some gram-positive inhabitants of the GI tract, including three species of lactobacilli, but in no case have the genes responsible for these activities been identified. Of the three Lactobacillus species previously studied, L. delbrueckii, L. fermentum, and L. rhamnosus, only the enzyme activity from L. rhamnosus has been partially characterized (37,42). Thus, this report describes the first gusA gene to be cloned from a bacterial source other than E. coli.…”

Section: Discussionmentioning

confidence: 97%

“…Indeed, their frequent exposure to bile is reflected in the common occurrence of conjugated bile acid hydrolysis among different species (12,19). Lactobacilli themselves have not traditionally been associated with ␤-glucuronidase activity, however, and there have been, to date, only two reports of ␤-glucuronidase-like activity in lactobacilli (37,42). It has been unclear, however, whether this ␤-glucuronidase activity was the result of a true ␤-glucuronidase enzyme or reflected the activity of some other enzyme.…”

mentioning

confidence: 87%

“…It remains an important objective to characterize the physiological and enzymatic activities of this group of organisms and ultimately to identify the genetic factors responsible for those activities. Studies with various Lactobacillus species, including L. gasseri, have consistently shown their ability to reduce the amount of fecal ␤-glucuronidase activity and lower the occurrence of cancer indicators present in the GI tract (15,27,33,37,41). The mechanisms by which lactobacilli lower the amount of ␤-glucuronidase activity in the gut remain unknown but may be the reflection of a variety of activities including, but not limited to, the exclusion or antagonism of typically ␤-glucuronidase-positive enterobacteria.…”

mentioning

confidence: 99%

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Identification and Cloning of gusA , Encoding a New β-Glucuronidase from Lactobacillus gasseri ADH

Russell¹,

Klaenhammer

2001

Appl Environ Microbiol

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The gusA gene, encoding a new ␤-glucuronidase enzyme, has been cloned from Lactobacillus gasseri ADH. This is the first report of a ␤-glucuronidase gene cloned from a bacterial source other than Escherichia coli. A plasmid library of L. gasseri chromosomal DNA was screened for complementation of an E. coli gus mutant. Two overlapping clones that restored ␤-glucuronidase activity in the mutant strain were sequenced and revealed three complete and two partial open reading frames. The largest open reading frame, spanning 1,797 bp, encodes a 597-amino-acid protein that shows 39% identity to ␤-glucuronidase (GusA) of E. coli K-12 (EC 3.2.1.31). The other two complete open reading frames, which are arranged to be separately transcribed, encode a putative bile salt hydrolase and a putative protein of unknown function with similarities to MerR-type regulatory proteins. Overexpression of GusA was achieved in a ␤-glucuronidase-negative L. gasseri strain by expressing the gusA gene, subcloned onto a low-copy-number shuttle vector, from the strong Lactobacillus P6 promoter. GusA was also expressed in E. coli from a pET expression system. Preliminary characterization of the GusA protein from crude cell extracts revealed that the enzyme was active across an acidic pH range and a broad temperature range. An analysis of other lactobacilli identified ␤-glucuronidase activity and gusA homologs in other L. gasseri isolates but not in other Lactobacillus species tested.

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Section: Discussionmentioning

confidence: 97%

mentioning

confidence: 87%

mentioning

confidence: 99%

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Identification and Cloning of gusA , Encoding a New β-Glucuronidase from Lactobacillus gasseri ADH

Russell¹,

Klaenhammer

2001

Appl Environ Microbiol

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“…Weighed fecal samples were diluted approximately 1:10 in 0.1 M sodium phosphate broth (pH 6.5) and used to measure ␤-glucuronidase activity (15). Similarly, a fecal homogenate in 0.01 M potassium phosphate buffer (pH 7.0) was used to measure the azoreductase activity of each sample (14).…”

Section: Methodsmentioning

confidence: 99%

Analysis of the Fecal Microflora of Human Subjects Consuming a Probiotic Product Containing Lactobacillus rhamnosus DR20

Tannock

Munro

Harmsen

et al. 2000

Appl Environ Microbiol

581

407

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The composition of the fecal microflora of 10 healthy subjects was monitored before (6-month control period), during (6-month test period), and after (3-month posttest period) the administration of a milk product containing Lactobacillus rhamnosus DR20 (daily dose, 1.6 ؋ 10 9 lactobacilli). Monthly fecal samples were examined by a variety of methods, including bacteriological culture analysis, fluorescent in situ hybridization with group-specific DNA probes, denaturing gradient gel electrophoresis of the V2-V3 region of 16S rRNA genes amplified by PCR, gas-liquid chromatography, and bacterial enzyme activity analysis. The composition of the Lactobacillus population of each subject was analyzed by pulsed-field gel electrophoresis of bacterial DNA digests in order to differentiate between DR20 and other strains present in the samples. Representative isolates of lactobacilli were identified to the species level by sequencing the V2-V3 region of their 16S rRNA genes and comparing the sequences obtained (BLAST search) to sequences in the GenBank database. DR20 was detected in the feces of all of the subjects during the test period, but at different frequencies. The presence of DR20 among the numerically predominant strains was related to the presence or absence of a stable indigenous population of lactobacilli during the control period. Strain DR20 did not persist at levels of >10 2 cells per g in the feces of most of the subjects after consumption of the product ceased; the only exception was one subject in which this strain was detected for 2 months during the posttest period. We concluded that consumption of the DR20-containing milk product transiently altered the Lactobacillus and enterococcal contents of the feces of the majority of consumers without markedly affecting biochemical or other bacteriological factors.

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“…Although physiological conditions in vivo are vastly different from in vitro model systems used for most studies, the presence of lactic acid bacteria in the intestine is postulated to limit the growth, metabolism or survival of other enteric bacteria, which may in turn limit pathogenic or toxigenic effects (7)(8)(9). Many other biological effects have been attributed to lactic acid bacteria, such as bile salt deconjugation (10), induction of higher tolerance to lactose when given to lactoseintolerant subjects (11,12), anticholesterolemic effects (13)(14)(15) and anticarcinogenic properties (16)(17)(18). The latter effect seems to be related to macrophage activity and recent studies have demonstrated that Lactobacillus and other lactic acid bacteria can increase the phagocytic capacity and enzymatic activity of mouse peritoneal cells (19)(20)(21)(22)(23).…”

Section: Introductionmentioning

confidence: 99%

Monoassociation with Lactobacillus acidophilus UFV-H2b20 stimulates the immune defense mechanisms of germfree mice

Neumann¹,

Oliveira²,

Cabral³

et al. 1998

Braz J Med Biol Res

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Probiotics are formulations containing live microorganisms or microbial stimulants that have some beneficial influence on the maintenance of a balanced intestinal microbiota and on the resistance to infections. The search for probiotics to be used in prevention or treatment of enteric infections, as an alternative to antibiotic therapy, has gained significant impulse in the last few years. Several studies have demonstrated the beneficial effects of lactic acid bacteria in controlling infection by intestinal pathogens and in boosting the hosts nonspecific immune response. Here, we studied the use of Lactobacillus acidophilus UFV-H2b20, a lactic acid bacterium isolated from a human newborn from Viçosa, Minas Gerais, Brazil, as a probiotic. A suspension containing 10 8 cells of Lactobacillus acidophilus UFV-H2b20 was inoculated into groups of at least five conventional and germfree Swiss mice to determine its capacity to stimulate the host mononuclear phagocytic activity. We demonstrate that this strain can survive the stressing conditions of the intestinal tract in vivo. Moreover, the monoassociation of germfree mice with this strain for seven days improved the hosts macrophage phagocytic capacity, as demonstrated by the clearance of a Gram-negative bacterium inoculated intravenously. Monoassociated mice showed an undetectable number of circulating E. coli, while 0.1% of the original inoculum was still present in germfree animals. Mice treated with viable or heat-killed Lactobacillus acidophilus UFV-H2b20 presented similarly improved clearance capacity when compared with germfree controls. In addition, monoassociated mice had twice the amount of Kupffer cells, which are responsible for the clearance of circulating bacteria, compared to germfree controls. These results suggest that the L. acidophilus strain used here stimulates a nonspecific immune response and is a strong candidate to be used as a probiotic.

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A note on lactobacilli and β‐glucuronidase activity in the intestinal contents of mice

Cited by 26 publications

References 11 publications

Identification and Cloning of gusA , Encoding a New β-Glucuronidase from Lactobacillus gasseri ADH

Identification and Cloning of gusA , Encoding a New β-Glucuronidase from Lactobacillus gasseri ADH

Analysis of the Fecal Microflora of Human Subjects Consuming a Probiotic Product Containing Lactobacillus rhamnosus DR20

Monoassociation with Lactobacillus acidophilus UFV-H2b20 stimulates the immune defense mechanisms of germfree mice

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