In this study, we analyzed the kinetics of bioconversion of conjugated linoleic acid (CLA) by permeabilized Lactobacillus acidophilus cells. The effects of cell mass, linoleic acid (LA) concentration, reaction pH and temperature on the bioconversion of CLA by permeabilized cells were investigated and the model system of bioconversion of CLA was established. The results showed that the production of CLA was increased by permeabilized cells. The optimal cell mass, pH and temperature of bioconversion of CLA were 10 x 10(10) ufc/mL, 4.5 and 45 degrees C, respectively. A marked LA inhibition phenomenon existed, and the early reaction rate of producing CLA reached the maximum (17.8 microg/mL x min) when LA concentration was 0.6 mg/mL. Michaelis constant was obtained by double-reciprocal plot and Hanes-Woolf plot. The reaction rate equation followed the classic Michaelis-Mentent equation at the low LA concentration, while there was a marked LA inhibition phenomenon at the high LA concentration. With the evaluated model parameters, the model system appeared to provide a description for the bioconversion of CLA by permeabilized Lactobacillus acidophilus cells.
Biotransformation ; Cell Membrane Permeability ; drug effects ; Kinetics ; Lactobacillus acidophilus ; metabolism ; Linoleic Acid ; chemistry ; metabolism ; Linoleic Acids, Conjugated ; chemistry ; metabolism

Lactobacillus species in the female genital tract are thought to act as a barrier to infection. Several studies have demonstrated that lactobacilli can adhere to vaginal epithelial cells. However, little is known about how the adherence of lactobacilli to vaginal epithelial cells affects the acidity, cell viability, or proliferation of the lactobacilli themselves or those of vaginal epithelial cells. Lactobacillus acidophilus was co-cultured with immortalized human vaginal epithelial cells (MS74 cell line), and the growth of L. acidophilus and the acidity of the culture medium were measured. MS74 cell density and viability were also assessed by counting cell numbers and observing the cell attachment state. L. acidophilus showed exponential growth for the first 6 hr until 9 hr, and the pH was maintained close to 4.0-5.0 at 24 hr after culture, consistent with previous studies. The growth curve of L. acidophilus or the pH values were relatively unaffected by co-culture with MS74 cells, confirming that L. acidophilus maintains a low pH in the presence of MS74 cells. This co-culture model could therefore potentially be used to mimic vaginal conditions for future in vitro studies. On the other hand, MS74 cells co-cultured with L. acidophilus more firmly attached to the culture plate, and a higher number of cells were present compared to cells cultured in the absence of L. acidophilus. These results indicate that L. acidophilus increases MS74 cell proliferation and viability, suggesting that lactobacilli may contribute to the healthy environment for vaginal epithelial cells.
Cell Adhesion ; Cell Line ; Cell Survival ; Coculture Techniques ; Culture Media/chemistry ; Epithelial Cells/*microbiology/*physiology ; Female ; Humans ; Hydrogen-Ion Concentration ; Lactobacillus acidophilus/growth & development/metabolism/*physiology ; Time Factors

OBJECTIVETo construct a recombinant Lactobacillus acidophilus that expresses high levels of Helicobacter pylori (Hp) adhesin Hp0410.

METHODSThe gene fragment encoding Hp0410 was amplified by PCR from the DNA of H. pylori NCTC11639 strain and cloned into the shuttle plasmid pMG36e to construct pMG36e-Hp0410, which was transformed into Lactobacillus acidophilus by electroporation. The target protein was confirmed with SDS-PAGE and silver nitrate staining and analyzed by Western blotting. The stability of the recombinant plasmid was assessed by drawing the growth curve of the recombinant Lactobacillus acidophilus.

RESULTSA 750-bp fragment was inserted into the pMG36e plasmid and transformed into Lactobacillus lactis. The transformed bacterium expressed the target protein with a relative molecular mass of about 34 kD. Western blotting confirmed that the expressed proteins could be recognized by the serum of patients with Hp infection. The recombinant plasmid pMG36e-Hp0410 exhibited good stability in the presence or absence of erythromycin.

CONCLUSIONSThe recombinant Lactobacillus acidophilus with high constitutive expression of Hp0410 has been constructed successfully.

Adhesins, Bacterial ; biosynthesis ; genetics ; immunology ; Bacterial Vaccines ; biosynthesis ; Helicobacter Infections ; prevention & control ; Humans ; Lactobacillus acidophilus ; genetics ; metabolism ; Plasmids ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Vaccines, Attenuated ; biosynthesis

Radiation therapy is an important treatment modality for abdominal or pelvic cancer, but there is a common and serious complication such as radiation-induced enteritis. Probiotics is reported to have positive effects against radiation-induced enteropathy. In this study, morphological changes of bowel mucosa were analyzed in rats to presume the effect of probiotics on radiation-induced enteritis and its correlation with radiation dose. A total of 48 adult male Sprague-Dawley rats were randomly assigned to two groups and received a solution containing 1.0x108 colony-forming units of Lactiobacillus acidophilus or water once daily for 10 days. Each of two groups was divided into three subgroups and abdomino-pelvic area of each subgroup was irradiated with 10, 15, and 20 Gy, respectively on the seventh day of feeding the solutions. All rats were sacrificed 3 days after irradiation and the mucosal thickness and villus height of jejunum, ileum and colon were measured. The morphological parameters of the small intestine represented significant differences between two solution groups irradiated 10 or 15 Gy, except for villus height of jejunum in 15 Gy-subgroup (P=0.065). There was no significant morphometric difference between two groups irradiated with 20 Gy of radiation. Probiotics appear to be effective for the morphological shortening of small intestinal mucosa damaged by radiation less than or equal to 15 Gy.
Animals ; Colon/pathology ; Disease Models, Animal ; Enteritis/pathology/prevention & control ; Ileum/pathology ; Intestinal Mucosa/microbiology/*radiation effects ; Intestine, Small ; Jejunum/pathology ; Lactobacillus acidophilus/*metabolism ; Male ; Probiotics/administration & dosage/*pharmacology ; Radiation Injuries, Experimental/*prevention & control/therapy ; Radiation Protection/*methods ; Random Allocation ; Rats ; Rats, Sprague-Dawley