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Category: Clinical Microbiology; General Interest
Bifidobacteria and Their Health-Promoting Effects, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555819705/9781555819699_Chap03-1.gif /docserver/preview/fulltext/10.1128/9781555819705/9781555819699_Chap03-2.gifAbstract:
The genus Bifidobacterium is included within the phylum Actinobacteria, class Actinobacteria (high G+C Gram-positive bacteria), order Bifidobacteriales, and family Bifidobacteriaceae. Currently, this genus contains more than 50 species, including several subspecies; this number rises every year. From a metabolic point of view, the more typical trait of this genus is the catabolism of monosaccharides. Bifidobacteria use a particular route for monosaccharide degradation, the so-called fructose 6-phosphate pathway, or bifid shunt. The fructose 6-phosphate phosphoketolase (Xfp) is the main enzyme of this path. Xfp possesses a dual-substrate specificity on fructose 6-phosphate or xylulose 5-phosphate. The end metabolites of the pathway are acetate, lactate, and ethanol ( 1 ). Xfp activity on fructose 6-phosphate is the most common phenotypic test for bifidobacteria, and for many years it has been the main taxonomic test to identify this genus, since this activity is present in members of the family Bifidobacteriaceae, but it is not present in other Gram-positive intestinal bacteria. However, currently, DNA-sequencing-based analyses are the standard techniques for identification and typing of bifidobacteria.
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Positive effects of some Bifidobacterium strains on gastrointestinal functions studied by means of human intervention studies.
Positive effects of some Bifidobacterium strains on gastrointestinal functions studied by means of human intervention studies.
Visualization of B. animalis subsp. lactis growth in skimmed milk by using confocal scanner laser microcopy. The staining method was previously reported by Ruas-Madiedo and Zoon ( 167 ); in short, two dyes, rhodamine B (which dyes proteins) and acridine orange (which dyes nucleic acids), were added to the milk at final concentration of 0.001 and 0.002%, respectively. Afterward, stained milk was inoculated (5%) and carefully placed into high-optical-quality plastic μ-Slides (Ibidi GmbH) for direct confocal laser scanning microscopy analysis. The microplates were incubated at 37°C until they reached a pH of ≤4.5, and the confocal microscope Ultra-Spectral Leica TCS AOBS SP2 (Leica Microsystems GmbH, located in the University of Oviedo facilities) was used. Bacteria dyed with acridine orange were visualized with the laser 488 nm ion argon/krypton (green), and proteins (mainly caseins) dyed with rhodamine B were visualized with the laser 543 nm He/Ne (red) but also with the laser 488 nm. Thus, after image treatment, the bacteria are visualized in green and the casein matrix in yellow (combination red and green). The oil immersion objective 63×/1.40 combined with an amplification zoom of 1.58 was directly used (×100 magnification). Microphotographs: (A) a Z-projection (thickness about 10 μm) of 10 slides of an XY-field (bar, 10 μm); (B) a slide of an XY-field (bar, 10 μm); (C) an optical zoom of a region inside the XY-field showed in B (bar, 5 μm).
Visualization of B. animalis subsp. lactis growth in skimmed milk by using confocal scanner laser microcopy. The staining method was previously reported by Ruas-Madiedo and Zoon ( 167 ); in short, two dyes, rhodamine B (which dyes proteins) and acridine orange (which dyes nucleic acids), were added to the milk at final concentration of 0.001 and 0.002%, respectively. Afterward, stained milk was inoculated (5%) and carefully placed into high-optical-quality plastic μ-Slides (Ibidi GmbH) for direct confocal laser scanning microscopy analysis. The microplates were incubated at 37°C until they reached a pH of ≤4.5, and the confocal microscope Ultra-Spectral Leica TCS AOBS SP2 (Leica Microsystems GmbH, located in the University of Oviedo facilities) was used. Bacteria dyed with acridine orange were visualized with the laser 488 nm ion argon/krypton (green), and proteins (mainly caseins) dyed with rhodamine B were visualized with the laser 543 nm He/Ne (red) but also with the laser 488 nm. Thus, after image treatment, the bacteria are visualized in green and the casein matrix in yellow (combination red and green). The oil immersion objective 63×/1.40 combined with an amplification zoom of 1.58 was directly used (×100 magnification). Microphotographs: (A) a Z-projection (thickness about 10 μm) of 10 slides of an XY-field (bar, 10 μm); (B) a slide of an XY-field (bar, 10 μm); (C) an optical zoom of a region inside the XY-field showed in B (bar, 5 μm).
Bifidobacterium strains used as probiotics with demonstrated effectivity in humans trials
Bifidobacterium strains used as probiotics with demonstrated effectivity in humans trials
Selection of meta-analyses and reviews about the effect of probiotic products containing bifidobacteria on certain diseases
Selection of meta-analyses and reviews about the effect of probiotic products containing bifidobacteria on certain diseases