Theaflavin and its derivatives exert antibacterial action against Bacillus coagulans through adsorption to cell surface phospholipids.

AIMS: To investigate the antibacterial effects of tea theaflavins and catechins against Bacillus coagulans and the underlying mechanism of antibacterial action. METHODS AND RESULTS: Bactericidal activities of theaflavin and its analogues were evaluated and compared with that of epigallocatechin gallate. Theaflavin derivatives exhibited high bactericidal activity at 50 µmol L-1 , whereas epigallocatechin gallate did not, even at 500 µmol L-1 . Furthermore, we investigated the adsorption of theaflavins to model phospholipid membranes and corresponding effects on membrane fluidity to reveal their effects on the B. coagulans cell surface. Cell membrane fluidity was decreased after treatment with theaflavin derivatives with one or more galloyl moieties. Quartz-crystal microbalance analysis showed a strong affinity of the membrane phosphatidyl glycerol (PG) bilayers for theaflavin derivatives, correlating their bactericidal activity. CONCLUSION: These findings suggest that theaflavins could effectively inhibit B. coagulans by decreasing cell membrane fluidity. SIGNIFICANCE AND IMPACT: Bacillus coagulans is a spore-forming heat-resistant bacterium responsible for spoilage in low-acidic beverages. Natural antimicrobial components in tea-based beverages are central to reducing microbial contamination and product quality deterioration, although mechanisms underlying their antimicrobial action remain obscure. This study highlights the inhibitory action of theaflavins on B. coagulans and their potential application in food and beverage industries.

Serum MicroRNA-Based Risk Prediction for Stroke.

Background and Purpose- Numerous studies have shown that circulating microRNAs (miRNAs) can be used as noninvasive biomarkers of various diseases. This study aimed to identify serum miRNAs that predict the risk of stroke. Methods- The cases were individuals who had been diagnosed with cerebrovascular disorder by brain imaging. The controls were individuals with no history of stroke who had undergone a medical checkup. Serum miRNA profiling was performed for all participants using microarray analysis. Samples were divided into discovery, training, and validation sets. In the discovery set, which consisted of control samples only, serum miRNAs that correlated with the predicted risk of stroke, as calculated using 7 clinical risk factors, were identified by Pearson correlation analysis. In the training set, a discriminant model between cases and controls was constructed using the identified miRNAs, Fisher linear discrimination model with leave-one-out cross-validation and DeLong test. In the validation set, the predictive accuracy of the constructed model was calculated. Results- First, in 1523 control samples (discovery set), we identified 10 miRNAs that correlated with a predicted risk of stroke. Second, in 45 controls and 87 cases (training set), we identified 7 of 10 miRNAs that significantly associated with cerebrovascular disorder (miR-1228-5p, miR-1268a, miR-1268b, miR-4433b-3p, miR-6090, miR-6752-5p, and miR-6803-5p). Third, a 3-miRNA combination model (miR-1268b, miR-4433b-3p, and miR-6803-5p) was constructed in the training set with a sensitivity of 84%, a specificity of 98%, and an area under the receiver operating characteristic curve of 0.95 (95% CI, 0.92-0.98). Finally, in 45 controls and 86 cases (validation set), the 3-miRNA model achieved a sensitivity of 80%, a specificity of 82%, and an area under the receiver operating characteristic of 0.89 (95% CI, 0.83-0.95) for cerebrovascular disorder. Conclusions- We identified 7 serum miRNAs that could predict the risk of cerebrovascular disorder before the onset of stroke.

Carob pod polyphenols suppress the differentiation of adipocytes through posttranscriptional regulation of C/EBPß.

Obesity is a major risk factor for various chronic diseases such as diabetes, cardiovascular disease, and cancer; hence, there is an urgent need for an effective strategy to prevent this disorder. Currently, the anti-obesity effects of food ingredients are drawing attention. Therefore, we focused on carob, which has high antioxidant capacity and various physiological effects, and examined its anti-obesity effect. Carob is cultivated in the Mediterranean region, and its roasted powder is used as a substitute for cocoa powder. We investigated the effect of carob pod polyphenols (CPPs) on suppressing increases in adipose tissue weight and adipocyte hypertrophy in high fat diet-induced obesity model mice, and the mechanism by which CPPs inhibit the differentiation of 3T3-L1 preadipocytes into adipocytes in vitro. In an in vivo experimental system, we revealed that CPPs significantly suppressed the increase in adipose tissue weight and adipocyte hypertrophy. Moreover, in an in vitro experimental system, CPPs acted at the early stage of differentiation of 3T3-L1 preadipocytes and suppressed cell proliferation because of differentiation induction. They also suppressed the expression of transcription factors involved in adipocyte differentiation, thereby reducing triacylglycerol synthesis ability and triglycerol (TG) accumulation. Notably, CPPs regulated CCAAT/enhancer binding protein (C/EBP)ß, which is expressed at the early stage of differentiation, at the posttranscriptional level. These results demonstrate that CPPs suppress the differentiation of adipocytes through the posttranscriptional regulation of C/EBPß and may serve as an effective anti-obesity compound.

Effect of epigallocatechin gallate on gene expression of Staphylococcus aureus.

OBJECTIVES: Staphylococcus aureus is an important nosocomial pathogen that produces various extracellular toxins. Epigallocatechin gallate (EGCg) is a polyphenol that is abundant in green tea. EGCg displays strong antibacterial activity against Gram-positive bacteria. The effect of EGCg on gene expression by S. aureus was investigated to clarify the mechanism underlying its antibacterial action. METHODS: Microarray analysis was performed on S. aureus treated with or without 500mg/L EGCg. Differentially expressed genes were identified and their changes at the transcription level were confirmed using real-time quantitative polymerase chain reaction (qPCR). The membrane potential of cells treated with or without EGCg were observed under fluorescence microscopy. RESULTS: Microarray analysis revealed that EGCg treatment of S. aureus resulted in increased and decreased transcription of 75 and 72 genes, respectively. Increased transcription exceeding 1-log2-fold change of genes related to membrane transport included gntP, gntK, rumA, SAOUHSC_02723, SAOUHSC_01311, and vraS. Decreased transcription was observed in genes involved in toxin production and stress response (hlgA, SAOUHSC_01110, hly, hlgB, efb, and hlgC). All changes in transcription were confirmed using real-time qPCR. The membrane potential of S. aureus treated with 500mg/L EGCg markedly decreased, indicating that EGCg damaged the cell membrane. CONCLUSIONS: S. aureus increases the transcription of genes involved in membrane transport to recover membrane function. EGCg can potentially serve as a natural antibacterial agent to control the growth and toxin production of S. aureus.

Integrated extracellular microRNA profiling for ovarian cancer screening.

A major obstacle to improving prognoses in ovarian cancer is the lack of effective screening methods for early detection. Circulating microRNAs (miRNAs) have been recognized as promising biomarkers that could lead to clinical applications. Here, to develop an optimal detection method, we use microarrays to obtain comprehensive miRNA profiles from 4046 serum samples, including 428 patients with ovarian tumors. A diagnostic model based on expression levels of ten miRNAs is constructed in the discovery set. Validation in an independent cohort reveals that the model is very accurate (sensitivity, 0.99; specificity, 1.00), and the diagnostic accuracy is maintained even in early-stage ovarian cancers. Furthermore, we construct two additional models, each using 9-10 serum miRNAs, aimed at discriminating ovarian cancers from the other types of solid tumors or benign ovarian tumors. Our findings provide robust evidence that the serum miRNA profile represents a promising diagnostic biomarker for ovarian cancer.

Evaluation of repetitive-PCR and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for rapid strain typing of Bacillus coagulans.

In order to establish rapid and accurate typing method for Bacillus coagulans strains which is important for controlling in some canned foods and tea-based beverages manufacturing because of the high-heat resistance of the spores and high tolerance of the vegetative cells to catechins and chemicals, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and repetitive-PCR (rep-PCR) were evaluated. For this purpose, 28 strains of B. coagulans obtained from various culture collections were tested. DNA sequence analyses of the genes encoding 16S rRNA and DNA gyrase classified the test strains into two and three groups, respectively, regardless of their phenotypes. Both MALDI-TOF MS and rep-PCR methods classified the test strains in great detail. Strains classified in each group showed similar phenotypes, such as carbohydrate utilization determined using API 50CH. In particular, the respective two pairs of strains which showed the same metabolic characteristic were classified into the same group by both MALDI-TOF MS and rep-PCR methods separating from the other strains. On the other hand, the other strains which have the different profiles of carbohydrate utilization were separated into different groups by these methods. These results suggested that the combination of MALDI-TOF MS and rep-PCR analyses was advantageous for the rapid and detailed typing of bacterial strains in respect to both phenotype and genotype.

Development of a ubiquitous healthcare monitoring system combined with non-conscious and ambulatory physiological measurements and its application to medical care.

The demand for ubiquitous healthcare monitoring has been increasingly raised for prevention of lifestyle-related diseases, acute life support or chronic therapies for inpatients and/or outpatients having chronic disorder and home medical care. From these view points, we developed a non-conscious healthcare monitoring system without any attachment of biological sensors and operations of devices, and an ambulatory postural changes and activities monitoring system. Furthermore in this study, in order to investigate those applicability to the ubiquitous healthcare monitoring, we have developed a new healthcare monitoring system combined with the non-conscious and the ambulatory measurements developed by us. In patients with chronic cardiovascular disease or stroke, the daily health conditions such as pulse, respiration, activities and so on, could be continuously measured in the hospital, the rehabilitation room and subject's own home, using the present system. The results demonstrated that the system appears useful for the ubiquitous healthcare monitoring not only at medical facility, but also during daily living at home.