الفهرس 
ProbioticsOnly 14 pages are availabe for public view
 |  | from | 218 |  |  |
| | | from | 218 | | |
Abstract
A total of 50 Lactobacillus isolates including Lactobacillus casei
(26%) , Lactobacillus paracasei (24%), Lactobacillus rhamnosus (20%),
Lactobacillus fermentum (14%), Lactobacillus zeae (12%), Lactobacillus
curvatus and Lactobacillus gasseri (2%) of each were recovered from
250 samples including 215 fecal samples from 3 days to1.5 years’ old
healthy breast – feed infants and 35 breast milk samples from apparently
healthy women. The identification of these isolates was based on cell,
colony morphology, preliminary biochemical tests and MULDI TOF
mass spectroscopy.
The cell free supernatant cultures (CFSCs) of these isolates were
screened for their evaluation of antimicrobial activities (estimated as
inhibition zone diameters) by well diffusion method against four
reference strains S. aureus, E. coli, S. typhi, and C. albicans. These
activities were expressed as descending order S. aureus > S. typhi > E.
coli > C.albicans.
The effects of physical factors including incubation temperature
(25oC, 37oC , 40oC ) and initial pH (5.5 , 6.4 , 6.8 and or 7.4) also the
effect of nutritional factors; carbon source in media
composition(glucose, fructose, starch) and nitrogen source (yeast ) on
the antimicrobial content were evaluated by well diffusion method
against reference strains. The highest production of antimicrobial
content was recoded at incubation temperature 37oC, pH 6.4 and
increased significantly up on enriched medium by glucose or fructose as
Abstract
a carbon source. On the other hand non-significant change was recoded
up on yeast addition. The antimicrobial activities of CFSCs of the tested
isolates grown at best condition was estimated against 20 clinical
isolates of S.aureus and E. coli each which resulted in higher activity
against S.aureus than E. coli.
The antioxidant and immunomodulator activities of Lactobacillus
isolates were also investigated. The total antioxidant capacity of the
tested isolates was evaluated by phosphopmelybdenum method. The
results revealed that the antioxidant activity of lactobacilli were varied
among different species, the Lactobacillus rhamnosus, Lactobacillus
fermentum and Lactobacillus zeae had greater antioxidant activity than
Lactobacillus casei, Lactobacillus paracasei. The effect of oral
administration of Lactobacillus paracasei on the mice was evaluated by
flowcytometry analysis to estimation the immunomodulator activities.
Data obtained showed that significant increase in the percentage of
CD11c subpopulation and level of IFN-γ compared to the control group.
Bacteriocins were partially purified from of CFSCs of Lactobacillus
isolates by ammonium sulphate method and its antimicrobial activities
were evaluated by well diffusion method. Electro photogram to 8
partially purified bacteriocin showed sharp single band at molecular
weight of about 70 KDa.