Purification and characterization of bacteriocin produced by a strain of Lacticaseibacillus rhamnosus ZFM216.

The recent surge in demand for natural preservatives has ushered in a new era of research into novel bacteriocins capable of effectively combating food-borne infections. In this study, the bacteriocin from Lacticaseibacillus rhamnosus ZFM216, which has a molecular mass of 11851.9 Da, was purified using macroporous resin, gel chromatography, and reversed-phase high performance liquid chromatography. This bacteriocin could inhibit both Gram-positive and Gram-negative bacteria. It had a strong inhibitory effect on Staphylococcus aureus D48 with minimum inhibitory concentration values of 1.75 µM. Bacteriocin ZFM216 was heat stable and showed pH stability under weakly acidic conditions. It was sensitive to pepsin, proteinase K and trypsin. Electron microscopy results showed that when treated with bacteriocin ZFM216, S. aureus D48 was severely deformed, the cell structure was obviously changed, and the intracellular electrolyte leaked to the outside of the cell. Bacteriocin ZFM216 caused the ATP level of the indicator to decrease, the conductivity to sharply increase, and the transmembrane potential difference (ΔΨ) to instantaneously decrease. This research formed the basis for further development and utilization of bacteriocin ZFM216 which has potential in the food industry.

The Effect of Indole-3-Lactic Acid from Lactiplantibacillus plantarum ZJ316 on Human Intestinal Microbiota In Vitro.

Microbiota-derived tryptophan metabolites are essential signals for maintaining gut homeostasis, yet the potential contribution to modulating gut microbiota has been rarely investigated. In this study, Lactiplantibacillus plantarum ZJ316 (CCTCC No. M 208077) with a high production (43.14 µg/mL) of indole-3-lactic acid (ILA) was screened. ILA with 99.00% purity was prepared by macroporous resin, Sephadex G-25 and reversed-phase high-performance liquid chromatography. Purified ILA can effectively inhibit foodborne pathogens such as Salmonella spp., Staphylococcus spp., Escherichia coli and Listeria monocytogenes. In an in vitro model of the human gut microbiota, a medium-dose ILA (172 mg/L) intervention increased the average relative abundance of phyla Firmicutes and Bacteroidota by 9.27% and 15.38%, respectively, while Proteobacteria decreased by 14.36% after 24 h fermentation. At the genus level, the relative abundance of Bifidobacterium and Faecalibacterium significantly increased to 5.36 ± 2.31% and 2.19 ± 0.77% (p < 0.01), respectively. Escherichia and Phascolarctobacterium decreased to 16.41 ± 4.81% (p < 0.05) and 2.84 ± 1.02% (p < 0.05), respectively. Intestinal short-chain fatty acids, especially butyric acid, were significantly increased (2.98 ± 0.72 µmol/mL, p < 0.05) and positively correlated with Oscillospira and Collinsella. Overall, ILA has the potential to regulate the gut microbiota, and an in-depth understanding of the relationship between tryptophan metabolites and gut microbiota is needed in the future.

Simultaneous identification of the three active constituents in Lung-Ventilating-Regulating Oral Liquid by RP-HPLC.

The study aimed to develop a HPLC method for ephedrine, hesperidin, and baicalin in Lung-Ventilating-Regulating Oral Liquid. The three active constituents were identified in an Agilent TC-C18 (2) chromatographic column (250mm × 4.6mm, 5µm), with 0.2% phosphoric acid solution - methyl cyanides as mobile phase, which was performed at a gradient elution column temperature of 25oC and a flow rate of 0.8 mL•min-1. Then the eluate was detected at detection wavelengths of 207 nm (for ephedrine) and 278 nm (for hesperidin and baicalin). Under the chromatographic conditions, ephedrine, hesperidin, and baicalin were well separated, which showed good linear relationships at 0.158-2.370, 0.164-4.100 and 0.160-4.000µg, respectively. The coefficients of recovery of these three kinds of samples showed 100.2%, 98.7% and 97.8%, respectively. The developed method is convenient, accurate and well repeatable, and consequently can be applied for the quality control of Lung-Ventilating-Regulating Oral Liquid.

Navel Orange Peel Essential Oil To Control Food Spoilage Molds in Potato Slices.

The aim of this study was to investigate the efficacy of navel orange, Citrus sinensis (L.) Osbeck, peel essential oil (NOPEO) for inhibiting spoilage fungi in potato slices. Sixteen different components accounting for 99.79% of the headspace components of NOPEO were identified by gas chromatography-mass spectrometry. d-Limonene was the major component of NOPEO. Antifungal activity of NOPEO was tested in vitro and in vivo against four foodborne fungi. A MIC of NOPEO against the four fungal species was 9.40 µL/mLair. NOPEO provided about 74, 74, 73, and 69% protection against Aspergillus niger, Mucor wutungkiao, Penicillium funiculosum, and Rhizopus oryzae at 2.00 µL/mLair concentration, respectively. NOPEO has been demonstrated to significantly improve the microbiological quality of potato slices.

Recombinant human interleukin-11 (IL-11) is a protective factor in severe sepsis with thrombocytopenia: A case-control study.

OBJECTIVE: To examine the platelet recovering and anti-inflammatory effects of IL-11 in the treatment of sepsis, accompanied with thrombocytopenia and to investigate the associated mechanisms via a case-control study. METHODS: 105 patients enrolled for the study were segregated into (1) IL-11 therapy group and (2) conventional therapy group. The IL-11 therapy group was given additional recombinant human IL-11 treatment. Laboratory examinations of IL-11, IL-6, TNF-α, PT, APTT, WBC, PLT counts in blood routine assays and PCT, CRP and APACHE II scores were performed and the results were recorded. RESULTS: The PLT counts in the IL-11 therapy group were higher than those in the conventional therapy group. No obvious difference in WBC counts or CRP levels was observed between the two groups. The highest levels of TNF-α were observed on day 3 in the conventional therapy group while it was observed on day 1 in the IL-11 therapy group, both of which subsequently declined gradually. The level of IL-6 was significantly lower in the IL-11 therapy group from 3 to 14 days, while there was a gradual elevation of IL-11. IL-11 therapy downregulated the expression of the sepsis indicator PCT and reduced the APACHE II score from 3 to 14 days. The conventional therapy group had a significantly higher mortality rate within 28 days. CONCLUSION: IL-11 has a protective role and can accelerate recovery of platelets, and remarkably lessen the extent of inflammatory responses, hence reducing the mortality in sepsis patients accompanied with thrombocytopenia.

[Triterpenoids and steroids of root of Rubus biflorus].

OBJECTIVE: To investigate the chemical constituents of root of Rubus biflorus. METHODS: Isolation and purification were carried out by silica gel column chromatography and recrystallization and so on. Structural determination of the pure compounds was based on physico-chemical properties and various spectral data analysis (1H-NMR, 13C-NMR, IR, EI-MS). RESULTS: Five compounds were isolated and identified as follows: lupeol acetate (I), corosolic acid (II), oleanic acid (III), 2alpha-hydroxyoleanolic acid (IV), sitosterol (V). CONCLUSION: All these compounds are isolated from this plant for the first time.