Transcriptomic and proteomic analysis of Staphylococcus aureus response to cuminaldehyde stress.

The previous study indicated that cuminaldehyde (CUM) could be used as an antibacterial agent in sauced beef to reduce the propagation of Staphylococcus aureus (S. aureus). This research took sauced beef treated with 0.4 µL/mL CUM as the research object. Transcriptomic and proteomic methods were used to comprehensively analyze the changes in genes and proteins of S. aureus under CUM stress. A total of 258 differentially expressed genes (DEGs, 178 up-regulated and 80 down-regulated) and 384 differentially expressed proteins (DEPs, 61 up-regulated and 323 down-regulated) were found. It was observed that CUM destroyed the cell wall and cell membrane by inhibiting the synthesis of peptidoglycan and fatty acid. Low energy consumption strategies were formed by reducing glycolysis and ribosome de novo synthesis. The levels of genes and proteins associated with the glycine, serine, threonine, methionine, cysteine, and branched-chain amino acids were dramatically changed, which impaired protein synthesis and reduced bacterial viability. In addition, the up-regulated DEGs and DEFs involved in DNA replication, recombination and single-stranded DNA-binding contributed to DNA repair. Moreover, ATP-binding cassettes (ABC) transporters were also perturbed, such as the uptake of betaine and iron were inhibited. Thus, this study revealed the response mechanism of S. aureus under the stress of CUM, and provided a theoretical basis for the application of CUM in meat products.

Biocatalytical Acyl-Modification of Puerarin: Shape Gut Microbiota Profile and Improve Short Chain Fatty Acids Production in Rats.

Gut microbiota balance and metabolites have become a potentially mechanism in maintaining health. The specific aim of this study was to compare the modulation of puerarin and puerarin acid esters on gut microbial composition and metabolites. Male mice were fed a control diet or diets supplemented with puerarin, puerarin propanoate ester, puerarin hexanoate ester, puerarin myristate ester for 24 h, respectively. The result revealed that puerarin acid esters with different chain lengths showed different activities to create more own impacted bacterial. Puerarin propanoate and puerarin hexanoate ester significantly improved the diversity of microbiota and promoted the relative abundance of beneficial gut microbiota such as Lactobacillus, Barnesiella, Clostridium IV, Prevotella. Additionally, the puerarin propanoate ester group showed the capacity to deliver specific propionic acid to the colon. But esters with medium-long chain lengths had more opportunity to alter gut microbiota for enhancing the short chain fatty acids production. As a whole, puerarin acid esters with different chain lengths supplements shaped different gut microbial and short chain fatty acids metabolism, which could improve human health.

Evaluation of the digestion and transport profiles and potential immunocompetence of puerarin and its acylated derivatives.

Acylation has become one of the most widely used methods to improve the lipid solubility and bioavailability of flavonoids. In this study, puerarin acid esters (PAES) with different chain lengths were synthesized via biocatalytic acylation. This was the first study to evaluate the digestion and transport profiles and immunocompetence of PAES. The relationship between the digestion and transport profiles and potential immunocompetence of the acylated derivatives in Caco-2 cell monolayers was also explored. Puerarin and PAES remained stable in gastric phases, whereas different degrees of hydrolysis of PAES were found in the intestine. PAES with less than 12 carbon chains were positively correlated with the degree of hydrolysis, while those with more than 12 carbon chains showed higher resistance to hydrolysis by the artificial human digestive juice. The apparent permeability coefficients of puerarin, puerarin acetate, puerarin propanoate, puerarin butyrate, puerarin hexanoate, puerarin octanate and puerarin laurate were 1.62 ± 0.09, 1.70 ± 0.15, 1.89 ± 0.19, 1.86 ± 0.18, 2.29 ± 0.12, 4.06 ± 1.01 and 2.32 ± 0.88 × 10-6 cm s-1, respectively, in Caco-2 cell monolayers. The results of the immune factor assays indicated that puerarin propanoate, puerarin hexanoate and puerarin myristate could significantly promote the secretion of IL-6, TNF-α and IL-10. These findings suggested that a better absorption could be predicted after oral intake using PAES. Meanwhile, the concentration of esters and their metabolites (puerarin) found in the digestion and transport profiles directly affected their potential immunocompetence.

Detection of viable but nonculturable Escherichia coli O157:H7 using propidium monoazide treatments and qPCR.

Escherichia coli O157:H7 can enter into a viable but nonculturable (VBNC) state under stress conditions. The aims of the present study were to examine the influences of environmental factors on the survivability and culturability of E. coli O157:H7 and to develop an approach for accurate detection of VBNC E. coli O157:H7. The E. coli O157:H7 strain ATCC 6589 was inoculated into 3 induction microcosm models: (i) Luria-Bertani broth, (ii) sterilized tap water, and (iii) sterilized physiological saline solution. Our results showed that low temperature and nutritional starvation significantly impacted on the survivability of E. coli O157:H7 cells and that the in-vitro-induced VBNC cells were capable of resuscitating under normal temperature and appropriate nutrients. We tested the effectiveness of an approach combining propidium monoazide (PMA) treatment with real-time polymerase chain reaction (PMA-qPCR) for accurate quantification of total, viable, dead, and VBNC cells under different induction microcosm models. Our results indicated different threshold cycle (Ct) values for PMA-treated cells and untreated cells (ΔCt = 4.97, 4.29, and 3.30 for Luria-Bertani broth, sterilized tap water, and sterilized physiological saline solution, respectively). We determined the quantification limit of this PMA-qPCR approach to be 1 × 10(2) cells·mL(-1), providing sufficient sensitivity for detection of VBNC E. coli O157:H7 cells to no less than 100 cells·mL(-1). This study clearly demonstrated the feasibility and effectiveness of using PMA-qPCR to accurately quantify E. coli O157:H7 in a VBNC state.

In vitro antioxidant activity of Bombax malabaricum flower extracts.

CONTEXT: Bombax malabaricum DC. (Bombacaceae) is a traditional Chinese herbal medicine used for the treatment of inflammatory conditions, diarrhea, fever, chronic inflammation, catarrhal affection, and as a diuretic. However, little information is available about its antioxidative activity. OBJECTIVE: Water, 50% ethanol, and 80% acetone extracts from flowers of B. malabaricum were investigated for their in vitro antioxidant activity in this article for the first time. Then the relationships between antioxidant activity measured by different methods and total phenolic content (TPC) and total flavonoid content (TFC) were established. MATERIALS AND METHODS: The antioxidant activities of extracts from B. malabaricum flower were investigated including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, oxygen radical absorbance capacity (ORAC), reducing power, and inhibition on phosphatidylcholine liposome peroxidation. RESULTS: Results showed that all the extracts possessed remarkable antioxidant capacity compared with ascorbic or gallic acids. Total antioxidant activities evaluated by ORAC assay of different extracts ranged from 700.03 to 1482.46 µmol Trolox equivalents/g. The highest TPC of 130.38 mg gallic acid equivalents (GAE)/g was observed in 80% acetone extract, whereas the lowest TPC of 57.09 mg GAE/g was obtained in the water extract. Furthermore, TFC exhibited significant (P < 0.05) positive correlations with DPPH radical-scavenging activity, ORAC, and reducing power. DISCUSSION AND CONCLUSION: These findings demonstrate that the flowers of B. malabaricum have excellent antioxidant activities and thus might be a potential source of natural antioxidants.

A multipathogen selective enrichment broth for simultaneous growth of Salmonella enterica serovar Enteritidis, Staphylococcus aureus, and Listeria monocytogenes.

A selective enrichment broth (SSL) was formulated to allow concurrent growth of 3 prominent food-borne pathogens: Salmonella enterica serovar Enteritidis, Staphylococcus aureus, and Listeria monocytogenes. Nalidixic acid, lithium chloride, and potassium tellurite were added as the selective agents, while sodium pyruvate and mannitol were employed as the supplemented elements. In the individual growth trial, the target pathogens were capable of growing in SSL to as high as 7-8 log(10) colony-forming units (CFU)/mL after 24 h incubation at 37 degrees C when being inoculated at 50-100 CFU/mL. In the simultaneous growth trial, the 3 combined target pathogens showed similar growth rates. The results show that SSL could support the successful simultaneous enrichment of 3 pathogens; however, SSL inhibited the growth of nontarget bacteria. In the artificial contaminated raw beef and ready-to-eat chicken, a high recovery of these 3 target pathogens was obtained in SSL. Finally, Salmonella Enteritidis, Staphylococcus aureus, and L. monocytogenes were detected from 710 suspicious food samples by SSL with real-time PCR, and no false-positive or -negative results were reported. In summary, SSL has been shown to be a suitable broth for the simultaneous detection of the 3 prominent food-borne pathogens by multipathogen detection on a single-assay platform.

A multipathogen selective enrichment broth for simultaneous growth of Salmonella spp., Vibrio parahaemolyticus, and Vibrio cholerae.

A selective enrichment broth (SVV) was formulated to allow concurrent growth of Salmonella spp., V. parahaemolyticus, and V. cholerae. Potassium tellurite and sodium citrate were added as the inhibitors, while glucose, mannitol, anhydrous sodium sulfite and sodium pyruvate were employed as the growth-promoters. When mixed in equal or varied proportions, the target pathogens in SVV had a great accumulation (10(5)-10(8) CFU/ml) and effectively inhibited the growth of competitive microflora. In the artificially contaminated samples, a high recovery of these 3 target pathogens was obtained in SVV. Finally, Salmonella spp., V. parahaemolyticus, and V. cholerae were detected from 608 suspicious food samples by SVV with real-time PCR, and no false-positive or -negative results were reported. In summary, SVV has been shown to be a suitable broth for the simultaneous detection of the 3 pathogens by multipathogen detection on a single-assay platform.

Simultaneous detection of enterovirus 70 and coxsackievirus A24 variant by multiplex real-time RT-PCR using an internal control.

Epidemics of acute hemorrhagic conjunctivitis are always explosive and extensive, and have been recognized as a serious international public health problem. Enterovirus 70 and coxsackievirus A24 variant have been identified as the major etiological agents in acute hemorrhagic conjunctivitis outbreaks worldwide. A novel multiplex real-time RT-PCR assay was developed for simultaneous detection, identification and quantitation of enterovirus 70 and coxsackievirus A24 variant. The specificity, sensitivity and reproducibility of the method were analyzed and 125 clinical samples were tested using this method. No cross-reactivity with other enteroviruses strains was detected. The detection limits achieved were 10 copies/tube of enterovirus 70 and 100 copies/tube of coxsackievirus A24 variant respectively, and the addition of the internal control does not compromise the sensitivity or specificity. One hundred and twenty five clinical samples were tested and the results were consistent with the results obtained by using virus isolation followed by neutralization and sequencing of VP1 region. Due to its high specificity, sensitivity and elimination of false negative results by the internal control, this assay is suitable for both research applications and rapid clinical diagnosis of enterovirus 70 and coxsackievirus A24 variant.

Simultaneous detection of human enterovirus 71 and coxsackievirus A16 in clinical specimens by multiplex real-time PCR with an internal amplification control.

The recent and continuing HFMD outbreak caused by EV71 in several provinces of China since March 2008 has affected thousands of children and resulted in nearly 50 deaths. In this study, a sensitive and specific multiplex real-time RT-PCR assay has been developed for the rapid detection of EV71 and CV-A16. By using an internal amplification control, the real-time assay achieves detection of samples containing inhibitors and avoids false negatives. It should prove useful for clinical diagnosis of EV71 or CV-A16 infections.

Rapid detection of a highly virulent Chinese-type isolate of Porcine Reproductive and Respiratory Syndrome Virus by real-time reverse transcriptase PCR.

An outbreak of highly virulent Chinese-type of Porcine Reproductive and Respiratory Syndrome Virus (H-PRRSV) in most areas of China recently has led to huge economic losses and drawn great attention to its diagnosis and disease control. To facilitate rapid identification of H-PRRSV, a fluorogenic-probe hydrolysis (TaqMan)-reverse transcriptase PCR for H-PRRSV has been developed. Primers and probe specificity were evaluated with RNA extracted from 5 strains of H-PRRSV and 24 strains of other viruses, the results showed 100% specificity for the selected panel. The assay met the sensitivity of 1 50% tissue culture infective dose (TCID50) per ml of samples from infected pigs. Analysis with 10(5)-1TCID50/ml H-PRRSV samples demonstrated high reproducibility with a coefficient of variation (CV) of 0.5-2.5%. More than two hundred samples from lung, spleen, blood serum specimens obtained from 22 outbreaks of suspected H-PRRS from March to June in 2007 were verified using this assay. The results showed that 68.5% (146 out of 213) of these samples were positive which is 100% consistent with that of the sequencing method. The assay can be performed in less than 3h and thus provide a rapid method for the diagnosis of H-PRRSV as well as for elucidation of the epidemiology of H-PRRSV infections.