This study aimed to evaluate the influence of 9 Lactobacillusplantarum with broad-spectrum antibacterial activity on fermented milk, including changes to the fermentation characteristics (pH, titration acidity, and viable counts), texture profile, relative content of volatile compounds, and sensory evaluation during 28-d storage at 4°C. First, L. plantarum IMAU80106, IMAU10216, and IMAU70095 were selected as candidates for further study because of their excellent coagulation and proteolytic activities. Subsequently, these L. plantarum strainswere supplemented to fermented milk produced by commercial yogurt starters (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) and a panel of parameters reflecting product quality was subsequently monitored during 28 d of postfermentation storage. The pH value and titration acidity of the fermented milk mildly fluctuated, whereas the L. plantarum viable counts remained stable along the storage period. Fourteen key volatile compounds were detected in the fermented milk by gas chromatography-mass spectrometry, and some flavor compounds were uniquely present in the L. plantarum-supplemented fermented milk (including 2,3-pentanedione, acetaldehyde, and acetate). No significant difference was shown in the sensory evaluation scores between samples with or without L. plantarum supplementation, but a gradual decrease was observed over storage in all samples. However, when L. plantarum was added, apparent shifts were observed in the overall quality of the fermented milk based on principal component analysis and multivariate ANOVA, particularly in the texture (adhesiveness) and volatile flavor compound profiles (acetaldehyde). Compared with L. plantarum IMAU80106 and IMAU10216, both the texture and volatile flavor profiles of IMAU70095 were closest to those of the control without adding the adjunct bacteria, suggesting that IMAU70095 might be the most suitable strain for further application in functional dairy product development. The current work has explored the potential of applying L. plantarum in fermented milk by performing thorough physical and chemical characterization. Our work is of intense interest to the dairy industry.
This study profiled the microbiota of patients with GM and indicated an important role for Corynebacterium, and in particular C. kroppenstedtii, in the pathogenesis of this disease.
Food deterioration is largely related to contamination by undesirable microorganisms; it can cause economical loss and serious health-related problems. Owing to increased awareness of health issues by consumers, biological food preservation using antibacterial Lactobacillus species is being increasingly studied. Here, we make a preliminarily assessment of the antibacterial activity of 347 Lactobacillus plantarum isolates against five common food-borne pathogens (Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium, and Shigella flexneri). Nine of these isolates had broad-spectrum antibacterial activity and were selected for further experimentation. Subsequent assays based on physical, chemical, and sensory evaluations of yoghurts fermented in the presence or absence of each of the selected isolates and persistence of antibacterial activity following protease challenge revealed that L. plantarum isolate IMAU10216 was superior to the other isolates. L. plantarum IMAU10216 also exhibited high in vitro gastrointestinal tract tolerance. To conclude, we have identified a novel bioactive antibacterial L. plantarum isolate with potential for use as a probiotic in the production of fermented milk or other related dairy products. Further in vivo studies are now required.
Although human breast ducts and terminal ductal lobular units (TDLUs) share the same cell types, ample evidence shows that TDLUs are the predominant site for the origin of breast cancer. Yet, there is still limited information concerning the molecular mechanisms. Analysis of transcriptomic profiles in TDLUs may provide insight into early breast tumorigenesis. We compared genome-wide expression profiles of 8 matched sets of breast main duct and TDLU samples, using significance analysis of microarray (SAM) software to screen differentially expressed genes (DEGs) with fold-change >2.0 and q-value <0.05. Moreover, we used Gene Ontology for functional enrichment analysis. We identified 472 DEGs between the two tissue types, and confirmed 17 randomly chosen DEGs by quantitative reverse transcription-PCR (qRT-PCR). Notably, hormone-related pathways were highly enriched in the TDLU samples, including various hormone-related DEGs that are associated with breast carcinogenesis and tumor progression. Oncogenic upregulation in TDLUs indicates a potential inappropriate or excessive response to successive hormone stimulus during the proliferation, differentiation and lactation cycles of the human mammary gland. Imbalanced hormone reactions may finally result in the early onset of neoplastic transformation that occurs mostly in breast TDLUs.
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