[Show abstract][Hide abstract] ABSTRACT: Soy milk is regarded as a substitute for milk and has become popular in varied diets throughout the world. It has been shown that a newly characterized probiotic bacterium (Lactobacillus casei Zhang) actually grows faster in soy milk than in bovine milk. To elucidate the mechanism involved, we carried out a proteomic analysis to characterize bacterial proteins that varied upon growth in soy milk and bovine milk at 3 different growth phases, and compare their expression under these conditions. A total of 104 differentially expressed spots were identified from different phases using a peptide mass ﬁngerprinting assay. Functional analysis revealed that a major part of these identified proteins is associated with transport and metabolism of carbohydrates, nucleotides, and amino acids as well. The results from our proteomic analysis were clarified by real-time quantitative PCR assay, which showed that Lb. casei Zhang loci involved in purine and pyrimidine biosynthesis were transcriptionally enhanced during growth in soy milk at lag phase (pH 6.4), whereas the loci involved in carbohydrate metabolism were upregulated in bovine milk. Particularly, our results showed that l-glutamine might play an important role in the growth of Lb. casei Zhang in soy milk and bovine milk, perhaps by contributing to purine, pyrimidine, and amino sugar metabolism.
No preview · Article · Jul 2013 · Journal of Dairy Science
[Show abstract][Hide abstract] ABSTRACT: Fermented soymilk was produced with the single culture of the six probiotic strains, including Lactobacillus casei Zhang, Bifidobacterium animalis ssp. lactis V9, Lactobacillus acidophilus NCFM, Lactobacillus rhamnosus GG, Bifidobacterium animalis Bb12, and Lactobacillus casei Shirota, and their fermentation characteristics were evaluated. The free amino nitrogen of soymilk fermented with the four probiotic strains, L. casei Zhang, B. animalis V9, L. acidophilus NCFM and L. rhamnosus GG, increased greatly. Significant increases in viable counts were observed among the six probiotic strains. All the fermented soymilk had a viable count above 8.69 log CFU/g at the end of fermentation, especially the four probiotic strains of L. casei Zhang, L. acidophilus NCFM, B. animalis Bb12, and L. casei Shirota, which were all over 9.00 log CFU/g. The content of glucose and fructose decreased for all the six probiotic strains after the fermentation, but along with the reduction in the content of stachyose and raffinose only for B. animalis V9, L. rhamnosus GG, and B. animalis Bb12. Our results indicated that the six probiotic strains can grow well and increase the contents of bioactive substances in soymilk, including γ-aminobutyric acid, vitamin B6, and total isoflavone aglycone, and deserves further research on utilization as potential starters for soymilk.
No preview · Article · Dec 2012 · Annals of Microbiology
[Show abstract][Hide abstract] ABSTRACT: Lactobacillus casei Zhang is a new probiotic strain isolated from koumiss in Inner Mongolia of China, which has been commercially used as starter in the manufacture of dairy products. To study gene expression profile of L. casei Zhang during growth in milk, a whole-genome microarray was used. Compared to L. casei Zhang grown to the late logarithmic phase in milk, 61 genes were significantly up-regulated (>5 fold) in the stationary phase, whereas 26 genes were down-regulated. Collectively, these data showed that the majority of the identified genes were involved in carbohydrate metabolism and energy production, followed by genes involved in nucleotide metabolism, inorganic ion transport, amino acid transport and metabolism, chaperones, etc. This study demonstrates the fundamental effects of cultural conditions on the transcriptome of L. casei Zhang. Moreover, it improves the understanding of growth and survival mechanism of the bacterium during the late stage of milk fermentation.
[Show abstract][Hide abstract] ABSTRACT: Studies have found that the survival of probiotics could be strongly enhanced with dairy products as delivery vehicles, but the molecular mechanism by which this might occur has seldom been mentioned. In this study, microarray technology was used to detect the gene expression profile of Lactobacillus casei Zhang with and without fermented milk used as a delivery vehicle during transit in simulated gastrointestinal juice. Numerous genes of L. casei Zhang in strain suspension were upregulated compared to those from L. casei Zhang in fermented milk. These data might indicate that L. casei Zhang is stimulated directly without the protection of fermented milk, and the high-level gene expression observed here may be a stress response at the transcriptional level. A large proportion of genes involved in translation and cell division were downregulated in the bacteria that were in strain suspension during transit in simulated intestinal juice. This may impede protein biosynthesis and cell division and partially explain the lower viability of L. casei Zhang during transit in the gastrointestinal tract without the delivery vehicle.
No preview · Article · Apr 2012 · Research in Microbiology
[Show abstract][Hide abstract] ABSTRACT: Lactobacillus delbrueckii subsp. bulgaricus strain ND02 is a Chinese commercial dairy starter used for the manufacture of yoghurt. It was isolated from naturally fermented
yak milk in Qinghai, China. Here, we report the main genome features of ND02 and several differences with two other published
genomes of Lactobacillus delbrueckii subsp. bulgaricus strains.
Full-text · Article · Jul 2011 · Journal of bacteriology
[Show abstract][Hide abstract] ABSTRACT: Lactobacillus helveticus strain H10 was isolated from traditional fermented milk in Tibet, China. We sequenced the whole genome of strain H10 and
compared it to the published genome sequence of Lactobacillus helveticus DPC4571.
Full-text · Article · Mar 2011 · Journal of bacteriology
[Show abstract][Hide abstract] ABSTRACT: Streptococcus thermophilus strain ND03 is a Chinese commercial dairy starter used for the manufacture of yogurt. It was isolated from naturally fermented
yak milk in Qinghai, China. We present here the complete genome sequence of ND03 and compare it to three other published genomes
of Streptococcus thermophilus strains.
Full-text · Article · Feb 2011 · Journal of bacteriology
[Show abstract][Hide abstract] ABSTRACT: Bifidobacterium animalis subsp. lactis strain V9 is a Chinese commercial bifidobacteria with several probiotic functions. It was isolated from a healthy Mongolian
child in China. We present here the complete genome sequence of V9 and compare it to 3 other published genome sequences of
B. animalis subsp. lactis strains. The result indicates the lack of polymorphism among strains of this subspecies from different continents.
Full-text · Article · Aug 2010 · Journal of bacteriology
[Show abstract][Hide abstract] ABSTRACT: The effect of four inoculation levels of Lactobacillus casei Zhang (0.001, 0.01, 0.1 and 1.0 g/100 g) on the fermentation characteristics of set-style yogurt, and the changes in viable counts of lactic acid bacteria, pH value, syneresis, apparent viscosity, sugar and organic acid contents were determined during fermentation and storage over 21 days. The presence of 0.001 to 0.01 g/100 g L. casei Zhang did not affect the growth of the yogurt strains, and the yogurt inoculated with 0.00 1 g/100 g of L. casei Zhang had the highest apparent viscosity among the samples. However, a high inoculated level of L. casei Zhang (1.0 g/100 g) resulted in yogurts with inferior quality.
No preview · Article · Dec 2009 · International Journal of Dairy Technology
[Show abstract][Hide abstract] ABSTRACT: Since 2004, our research group has isolated 240 Lactobacillus strains from Koumiss, a traditional fermented alcoholic beverage prepared from mare's milk in Inner Mongolia, Xinjiang of China and Mongolia. Among these Lactobacillus strains a novel strain with potential probiotic properties, Lactobacillus casei Zhang, was screened out and studied extensively for its probiotic properties, health-promoting effects and fermentation characteristics. In vitro tests indicated that L. casei Zhang had high tolerance to simulated gastric, intestine juices and bile salts, similar to commercial probiotic strains such as Lactobacillus acidophilus NCFM, Lactobacillus rhamnosus GG, L. casei Shirota and Bifidobacterium animalis Bb12. Higher acid-production activity and proteolytic activity was observed in the fermented milk inoculated with L. casei Zhang during the refrigerated storage than in the samples inoculated with the selected commercial probiotics. The yogurt samples fermented with L. casei Zhang exhibited similarer viable count (1.0×109cfu/mL) as the other samples after 28 d of refrigerated storage. The results suggested that L. casei Zhang showed good potential for application in functional foods and health-related products.
No preview · Article · Dec 2009 · Lebensmittel-Wissenschaft und-Technologie
[Show abstract][Hide abstract] ABSTRACT: Twenty-nine traditional fermented yak milk (kurut) and 15 traditional fermented Mongolian cow milk (FMCM) samples were collected from three regions of Tibet in China, and their chemical composition and microbiological properties were analyzed. Average levels of the major composition of kurut and FMCM, respectively, were as follows: total solid, 16.91+/-1.30 g/100 g and 12.65+/-1.14 g/100 g; fat, 6.83+/-1.18 g/100 g and 3.92+/-0.92 g/100 g; total protein, 4.93+/-0.36 g/100 g and 3.33+/-0.71 g/100 g; free amino acid, 8.57+/-3.22 mmol/l and 2.23+/-0.62 mmol/l; calcamin, 117.26+/-9.66 mg/100 g and 86.51+/-7.55 mg/100 g; and phosphorus, 109.28+/-7.97 mg/100 g and 78.86+/-6.99 mg/100 g. The average bacteria count of lactic acid bacteria in kurut and FMCM were 7.66+/-0.71 and 8.03+/-0.68 log colony-forming units (cfu)/ml, respectively. Moreover, the average yeast counts of these two samples were 6.48+/-0.81 and 5.92+/-0.52 log cfu/ml, respectively. The result showed that the major nutritional composition content of kurut was significantly higher than that of FMCM, which indicated that kurut can be considered an invaluable fermentation product for human being.
No preview · Article · Jul 2009 · International Journal of Food Sciences and Nutrition
[Show abstract][Hide abstract] ABSTRACT: From 16 samples of traditional fermented koumiss collected in Inner Mongolia Autonomous Region of China, forty-eight lactobacilli strains were isolated and phenotypically characterized by their abilities to ferment different carbohydrates and by additional biochemical tests. The dominant lactobacilli species were identified as L. casei (17 strains), L. helveticus (10 strains) and L. plantarum (8 strains), with a lower frequency of isolation for L. coryniformis subsp. coryniformis (5 strains), L. paracasei (3 strains), L. kefiranofaciens (2 strains), L. curvatus (1 strain), L. fermentum (1 strain) and W. kandleri (1 strain). The pH values of all these samples were ranging from 3.37 to 3.94. In isolates, L. casei Zhang, L. helveticus ZL12-1, and L. plantarum BX6-6 were selected as potentially probiotic strains through the preliminary tests including resistance to low acid, abilities to grow in MRS with bile salts, antimicrobial activities and the viabilities during prolonged cold storage in fermented milk. Moreover 16S rDNA was conducted to confirm the identification.
No preview · Article · Jun 2009 · Journal of Basic Microbiology
[Show abstract][Hide abstract] ABSTRACT: The fermentation characteristics of Lactobacillus casei Zhang in mare milk and transit tolerance during refrigerated storage for 28 days were evaluated. There were no dramatic changes in the viable counts of L. casei Zhang in the fermented mare milk samples during storage at various inoculation levels. L. casei Zhang showed good tolerance to the simulated transit juice and maintained high viability in mare milk (above 108cfu/g) during storage. Our results showed that L. casei Zhang had good probiotic properties, and suggest that mare milk could serve as the vehicle for the delivery of L. casei Zhang.
No preview · Article · May 2009 · International Journal of Dairy Technology