L-arabinose isomerase (L-AI) is the key enzyme for D-galactose isomerization of D-tagatose by biological method. In this research, Lactobacillus plantarum WU14 with high D-tagatose yield was identified as Lactobacillu...L-arabinose isomerase (L-AI) is the key enzyme for D-galactose isomerization of D-tagatose by biological method. In this research, Lactobacillus plantarum WU14 with high D-tagatose yield was identified as Lactobacillus plantarum was isolated from the number of lactic acid bacteria from pickled vegetables. The crude L-arabinose isomerase activity of Lactobacillus plantarum WU14 with high D-tagatose yield was 13.95 U/mL under the optimal temperature 60°C, pH 7.17 and substrate concentration 0.8 mol/L, and the conversion rate of 56.12% could be gained after 28 hours. Protein structure and specific of L-Arabinose Isomerase of Lactobacillus plantarum WU14 were researched. The results showed that L-arabinose isomerase is mainly composed of alpha helix and random coil. Then the recombinant L-AI gene was inserted into the food-grade expression vector pRNA48 and expressed in L. lactis NZ9000 successfully. The target protein expression reached the maximum amount when the induced concentration of nisin reaches 30 ng/mL after 12 h. And the crude enzyme activity of recombinant bacteria reached 6.21 U/mL under 60°C. Otherwise the optimal conversion rate recombinant of L. lactis NZ9000/pRNA48-L-AI can reach 39.21% under the temperature of 50°C, pH 7.17 and D-galactose concentration was 0.6 mol/L.展开更多
Background: Periodontal infections are the most common disease of cats and dogs. About 70% - 80% of them suffer from these infections during their lifetime. These infections occur in two forms, gingivitis and periodon...Background: Periodontal infections are the most common disease of cats and dogs. About 70% - 80% of them suffer from these infections during their lifetime. These infections occur in two forms, gingivitis and periodontitis. Gingivitis is a reversible inflammation of the gingiva which can be cured. As with humans, the harmful bacteria can cause infections also in organs such as the heart, liver and kidneys. Besides veterinary treatment, also the owner’s everyday care is essential. Objective: The aim of the study was to develop and clinically test easy home care probiotic product for cats’ and dogs’ oral health. Methods: Nine cats and thirteen dogs were given a combination of selected bacteria Streptococcus thermophilus SP4, Lactobacillus plantarum 14D and Lactobacillus rhamnosus SP1 (Petguide powder) in powder form daily for four weeks on top of the dry feed. Microbiological samples were taken before and after the intervention from each dog and cat. The samples were analyzed with flow cytometric analysis using Porphyromonas gingivalis and Fusobacterium sp. as indicators for oral health. Results: The home care treatment with these specific, live probiotic bacteria was shown to prevent the growth of infectious bacteria within four weeks. Petguide probiotic powder reduced the relative abundance of infectious microbes significantly (p = 0.005) in cats and dogs. Conclusion: The results suggest that the probiotic product with three live strains of probiotic bacteria prevents the growth of infectious bacterial species that are known to cause infections in pets’ mouths. Therefore, this probiotic combination could be used to improve the oral health of pets and increase their quality of life.展开更多
文摘L-arabinose isomerase (L-AI) is the key enzyme for D-galactose isomerization of D-tagatose by biological method. In this research, Lactobacillus plantarum WU14 with high D-tagatose yield was identified as Lactobacillus plantarum was isolated from the number of lactic acid bacteria from pickled vegetables. The crude L-arabinose isomerase activity of Lactobacillus plantarum WU14 with high D-tagatose yield was 13.95 U/mL under the optimal temperature 60°C, pH 7.17 and substrate concentration 0.8 mol/L, and the conversion rate of 56.12% could be gained after 28 hours. Protein structure and specific of L-Arabinose Isomerase of Lactobacillus plantarum WU14 were researched. The results showed that L-arabinose isomerase is mainly composed of alpha helix and random coil. Then the recombinant L-AI gene was inserted into the food-grade expression vector pRNA48 and expressed in L. lactis NZ9000 successfully. The target protein expression reached the maximum amount when the induced concentration of nisin reaches 30 ng/mL after 12 h. And the crude enzyme activity of recombinant bacteria reached 6.21 U/mL under 60°C. Otherwise the optimal conversion rate recombinant of L. lactis NZ9000/pRNA48-L-AI can reach 39.21% under the temperature of 50°C, pH 7.17 and D-galactose concentration was 0.6 mol/L.
文摘Background: Periodontal infections are the most common disease of cats and dogs. About 70% - 80% of them suffer from these infections during their lifetime. These infections occur in two forms, gingivitis and periodontitis. Gingivitis is a reversible inflammation of the gingiva which can be cured. As with humans, the harmful bacteria can cause infections also in organs such as the heart, liver and kidneys. Besides veterinary treatment, also the owner’s everyday care is essential. Objective: The aim of the study was to develop and clinically test easy home care probiotic product for cats’ and dogs’ oral health. Methods: Nine cats and thirteen dogs were given a combination of selected bacteria Streptococcus thermophilus SP4, Lactobacillus plantarum 14D and Lactobacillus rhamnosus SP1 (Petguide powder) in powder form daily for four weeks on top of the dry feed. Microbiological samples were taken before and after the intervention from each dog and cat. The samples were analyzed with flow cytometric analysis using Porphyromonas gingivalis and Fusobacterium sp. as indicators for oral health. Results: The home care treatment with these specific, live probiotic bacteria was shown to prevent the growth of infectious bacteria within four weeks. Petguide probiotic powder reduced the relative abundance of infectious microbes significantly (p = 0.005) in cats and dogs. Conclusion: The results suggest that the probiotic product with three live strains of probiotic bacteria prevents the growth of infectious bacterial species that are known to cause infections in pets’ mouths. Therefore, this probiotic combination could be used to improve the oral health of pets and increase their quality of life.
