Isolation and evaluation of probiotics from traditional Chinese foods for aflatoxin B1 detoxification: Geotrichum candidum XG1 (yeast) and mechanistic insights.

Identifying aflatoxin-detoxifying probiotics remains a significant challenge in mitigating the risks associated with aflatoxin contamination in crops. Biological detoxification is a popular technique that reduces mycotoxin hazards and garners consumer acceptance. Through multiple rounds of screening and validation tests, Geotrichum candidum XG1 demonstrated the ability to degrade aflatoxin B1 (AFB1) by 99-100%, exceeding the capabilities of mere adsorption mechanisms. Notably, the degradation efficiency was demonstrably influenced by the presence of copper and iron ions in the liquid medium, suggesting a potential role for proteases in the degradation process. Subsequent validation experiments with red pepper revealed an 83% reduction in AFB1 levels following fermentation with G. candidum XG1. Furthermore, mass spectrometry analysis confirmed the disruption of the AFB1 furan ring structure, leading to a subsequent reduction in its toxicity. Collectively, these findings establish G. candidum XG1 as a promising candidate for effective aflatoxin degradation, with potential applications within the food industry.

Antifungal mechanisms of binary combinations of volatile organic compounds produced by lactic acid bacteria strains against Aspergillusflavus.

Aspergillus flavus（A. flavus）, a common humic fungus known for its ability to infect agricultural products, served as the subject of investigation in this study. The primary objective was to assess the antifungal efficacy and underlying mechanisms of binary combinations of five volatile organic compounds (VOCs) produced by lactic acid bacteria, specifically in their inhibition of A. flavus. This assessment was conducted through a comprehensive analysis, involving biochemical characterization and transcriptomic scrutiny. The results showed that VOCs induce notable morphological abnormalities in A. flavus conidia and hyphae. Furthermore, they disrupt the integrity of the fungal cell membrane and cell wall, resulting in the leakage of intracellular contents and an increase in extracellular electrical conductivity. In terms of cellular components, VOC exposure led to an elevation in malondialdehyde content while concurrently inhibiting the levels of total lipids, ergosterol, soluble proteins, and reducing sugars. Additionally, the impact of VOCs on A. flavus energy metabolism was evident, with significant inhibition observed in the activities of key enzymes, such as Na+/K+-ATPase, malate dehydrogenase, succinate dehydrogenase, and chitinase. And they were able to inhibit aflatoxin B1 synthesis. The transcriptomic analysis offered further insights, highlighting that differentially expressed genes (DEGs) were predominantly associated with membrane functionality and enriched in pathways about carbohydrate and amino acid metabolism. Notably, DEGs linked to cellular components and energy-related mechanisms exhibited down-regulation, thereby corroborating the findings from the biochemical analyses. In summary, these results elucidate the principal antifungal mechanisms of VOCs, which encompass the disruption of cell membrane integrity and interference with carbohydrate and amino acid metabolism in A. flavus.

Impact of salt content on Douchi metabolites: biogenic amines, non-volatile compounds and volatile compounds.

BACKGROUND: The excessive salt intake associated with Douchi has become a topic of controversy. Addressing this concern and enhancing its market competitiveness necessitates the application of salt reduction fermentation in Douchi. Therefore, to promote the application of salt reduction fermentation in Douchi, a comprehensive study was undertaken aiming to investigate the differences in biogenic amines, volatile compounds and non-volatile compounds in Douchi with varying salt content. RESULTS: The findings unequivocally demonstrate that salt hampers the formation of metabolites in Douchi. As the salt content increased, there was a significant decrease (P < 0.05) in the levels of total acid, amino-type nitrogen and free amino acids in Douchi. Notably, when the salt content exceeded 80 g kg-1, there was a substantial reduction (P < 0.05) in putrescine, lactic acid and malic acid levels. Similarly, when the salt content surpassed 40 g kg-1, ß-phenethylamine and oxalic acid levels exhibited a significant decline (P < 0.05). Furthermore, the results of E-nose and principal component analysis based on headspace solid phase microextraction gas chromatography-mass spectrometry revealed notable discrepancies in the volatile compound content between Douchi samples with relatively low salt content (40 and 80 g kg-1) and those with relatively high salt content (120, 160 and 200 g kg-1) (P < 0.05). By employing partial least squares discriminant analysis, eight distinct volatile compounds, including o-xylene, benzaldehyde and 1-octen-one, were identified. These compounds exhibited higher concentrations in Douchi samples with relatively low salt content (40 and 80 g kg-1). The sensory results showed that Douchi samples with lower salt content exhibited higher scores in the soy sauce-like and Douchi aroma attributes. CONCLUSION: In conclusion, this study significantly enhances our understanding of the impact of salt on metabolites in Douchi and provides invaluable insights for the development of salt reduction fermentation in this context. © 2024 Society of Chemical Industry.

Impact of aroma-enhancing microorganisms on aroma attributes of industrial Douchi: An integrated analysis using E-nose, GC-IMS, GC-MS, and descriptive sensory evaluation.

In order to enhance the aromatic profile of industrial Douchi, a comprehensive investigation was undertaken to assess the impact of aroma-enhancing microorganisms on the sensory attributes of Douchi. This evaluation utilized a combination of analytical techniques, including electronic nose analysis, gas chromatography-ion mobility spectrometry (GC-IMS), gas chromatography-mass spectrometry (GC-MS), and descriptive sensory analysis (DA). Both GC-IMS and GC-MS revealed significant changes in the volatile composition of Douchi following the addition of aroma-enhancing microorganisms (p < 0.05). Partial least squares-discriminant analysis (PLS-DA) identified benzaldehyde, benzene acetaldehyde, 3-octanone, and ethyl 2-methylbutyrate as significant differentiating volatile compounds. Additionally, compared to the control group, the sensory attributes of sourness in Douchi were significantly reduced (p < 0.001), while the attributes of wine-like and sweetness were notably enhanced (p < 0.05) when the ratio of G. candidum to C. versatilis was 1:1 (GCC group). By calculating the odor-activity values (OAVs) of key volatiles, it can be hypothesized that this aroma improvement of Douchi may be attributed to an increase in the typical volatiles (3-methyl-1-butanol, 1-octen-3-ol, 3-octanol, and 3-octanone) and ethyl 2-methylbutanoate with high OAVs (2340849.64 âˆ¼ 16695327.86), as well as to decreases in the musty acetophenone. In conclusion, the aroma profile of Douchi was significantly enhanced when G. candidum and C. versatilis were added at a ratio of 1:1. This study provides valuable insights into the development of aroma enhancers for improving the sensory profile of Douchi.

Relationship between the Dynamics of Flavor Compounds and Microbial Succession in the Natural Fermentation of Zhalajiao, a Popular Traditional Chinese Fermented Chili Paste.

Zhalajiao, a traditional Chinese fermented food, is popular due to its unique flavor. Traditional Zhalajiao fermentation is closely related to flavor compounds production. However, the mechanisms underlying the formation of these crucial flavor components in Zhalajiao remain unclear. Here, we explored the dynamic changes in physical and chemical properties, microbial diversity, and flavor components of Zhalajiao at various fermentation times. In total, 6 organic acids, 17 amino acids, and 21 key volatile compounds were determined as flavor components. In Zhalajiao, Lactobacillus and Cyanobacterium were the main bacteria that were involved in the formation of crucial flavor compounds. Candida showed a significant correlation with 14 key flavor compounds during fermentation (p < 0.05) and was the main fungal genus associated with flavor formation in Zhalajiao. This research offers a theoretical foundation for the flavor regulation and quality assurance of Zhalajiao.

Safety assessment of Enterococcus lactis based on comparative genomics and phenotypic analysis.

Enterococcus faecium is sometimes used in food production; however, its acquisition of antibiotic resistance has become an alarming health concern. The E. lactis species is closely related to E. faecium and has good probiotic potential. This study aimed to investigate the antibiotic resistance of E. lactis. We analyzed the antibiotic resistance phenotype and whole-genome sequences of 60 E. lactis isolates (23, 29, and 8 isolates from dairy products, Rice wine Koji, and human feces, respectively). These isolates showed varying degree of resistance to 13 antibiotics, and were sensitive to ampicillin and linezolid. The E. lactis genomes carried only a subset of commonly reported antibiotic resistance genes (ARGs) in E. faecium. Five ARGs were detected across the investigated E. lactis, including two universally present genes (msrC and AAC(6')-Ii) and three rarely detected ARGs (tet(L), tetM, and efmA). To identify other undescribed antibiotic resistance-encoding genes, a genome-wide association study was performed, returning 160 potential resistance genes that were associated with six antibiotics, namely chloramphenicol, vancomycin, clindamycin, erythromycin, quinupristin-dalfopristin, and rifampicin. Only around one-third of these genes encode known biological functions, including cellular metabolism, membrane transport, and DNA synthesis. This work identified interesting targets for future study of antibiotic resistance in E. lactis. The fact that the lower number of ARGs present in E. lactis supports that it may be an alternative to E. faecalis for use in the food industry. Data generated in this work is of interest to the dairy industry.

Physicochemical, structure properties and in vitro hypoglycemic activity of soluble dietary fiber from adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) bran treated by steam explosion.

To enhance the content of adlay bran soluble dietary fiber (SDF) and improve its functionality, we investigated the influences of steam explosion (SE) on the physicochemical, structural properties, and in vitro hypoglycemic activities of adlay bran SDF. The cellulose, hemicellulose, and lignin contents of adlay bran decreased significantly after SE treatment. When the SE strength was 0.8 MPa for 3 min, the SDF content was 9.37%, which was a significant increase of 27.48% compared to the control. Under these conditions, SDF showed the highest oil-holding capacity (OHC) (2.18 g/g), cholesterol adsorption capacity (CAC) (27.29 mg/g), glucose adsorption capacity (GAC) (15.54 mg/g), glucose dialysis retardation index (GDRI) (36.57%), and α-Amylase activity inhibition ratio (α-AAIR) (74.14%). Compared with SDF from untreated adlay bran, SDF from SE-treated adlay bran showed lower weight molecular. In addition, differential scanning calorimetry (DSC) measurement showed that the peak temperature of SDF from adlay bran treated by SE increased by 4.19°C compared to the untreated SDF sample. The structure of SDF from adlay bran treated by SE showed that the SDF surface was rough and poriferous and the specific surface areas increased. In conclusion, SE pretreatment increases the content of SDF in adlay bran and improves its physicochemical, structural properties, and biological activities, which will be beneficial for the further exploitation of adlay bran.

Antifungal mechanisms of volatile organic compounds produced by Pseudomonas fluorescens ZX as biological fumigants against Botrytis cinerea.

To explore the antifungal mechanisms of volatile organic compounds (VOCs) produced by Pseudomonas fluorescens ZX against Botrytis cinerea, biochemical analyses and transcriptomic techniques were employed in this work. The results showed that P. fluorescens ZX-producing VOCs can increase the cell membrane permeability of B. cinerea and disrupt cell membrane integrity, resulting in leakage of the pathogen's cellular contents, inhibition of ergosterol biosynthesis (about 76%), and an increase in malondialdehyde (MDA) content. Additionally, for B. cinerea respiration, P. fluorescens ZX-producing VOCs (1 × 109 CFU /mL) significantly inhibited the activities of ATPase (55.7%), malate dehydrogenase (MDH) (33.1%), and succinate dehydrogenase (SDH) (57.9%), seriously interfering with energy metabolism and causing accumulation of reactive oxygen species (ROS). Furthermore, transcriptome analysis of B. cinerea following exposure to VOCs revealed 4590 differentially expressed genes (DEGs) (1388 upregulated, 3202 downregulated). Through GO analysis, these DEGs were determined to be enriched in intrinsic components of membrane, integral components of membrane, and membrane parts, while KEGG analysis indicated that they were enriched in many amino acid metabolism pathways. Significantly, the DEGs related to ergosterol biosynthesis, ATPase, mitochondrial respiratory chain, malate dehydrogenase, and cell membrane showed down-regulation, corroborating the biochemical analyses. Taken together, these results suggest that the antifungal activity of P. fluorescens ZX-producing VOCs against B. cinerea occurs primary mechanisms: causing significant damage to the cell membrane, negatively affecting respiration, and interfering with amino acid metabolism.

Distribution and natural variation of free, esterified, glycosylated, and insoluble-bound phenolic compounds in brocade orange (Citrus sinensis L. Osbeck) peel.

Brocade orange (Citrus sinensis L. Osbeck) peel, a by-product which is usually discarded in large amounts, is rich in a broad spectrum of phenols. Accordingly, this study investigated the distribution and natural variation of free, esterified, glycosylated and insoluble-bound phenols (FPs, EBPs, GBPs, and IBPs) in the peels. Regardless of phenolic fraction or peel position, the total phenol and flavonoid contents, and most tested phenolic compound contents were generally abundant during the immature and semi-mature stages but existed at lower levels during the commercial mature period. The flavedo was much richer than the albedo in a few phenolic acids, flavonols, flavones, and especially polymethoxyflavonoids, which was particularly true for EBPs. Flavanones, particularly in GBP form, were generally present in equal or even much higher levels in the albedo. The four phenolic forms exhibited distinct trends in terms of abundance. In the flavedo (except the young fruit stage) followed the order: EBPs > GBPs ≈ FPs ≫ IBPs, and in the albedo: GBPs ≫ FPs ≈ EBPs ≫ IBPs. Generally, the phenols examined for this study were highly abundant in the citrus peels, endowing this agricultural waste with great potential to be an excellent natural source of functional ingredients.

Bioeffector Pseudomonas fluorescens ZX Elicits Biosynthesis and Accumulation of Functional Ingredients in Citrus Fruit Peel: A Promising Strategy for a More Sustainable Crop.

Preharvest application of biocontrol agents is a promising strategy for promoting biosynthesis and accumulation of functional ingredients in fruit crops. In this study, we sought to evaluate the potential of Pseudomonas fluorescens ZX in stimulating the primary and secondary metabolism of citrus fruit peel. Pretreatment with P. fluorescens ZX was found to significantly affect the concentrations and profiles of both primary and secondary metabolites. More importantly, using P. fluorescens ZX suspension to increase inoculation numbers during fruit development typically elicited stronger stimulus effects, and multiple applications of P. fluorescens ZX significantly improved the biosynthesis process of beneficial compounds, resulting in their abundant accumulation in the peel. In fruit pretreated four times with P. fluorescens ZX, hesperidin, sinensetin, nobiletin, synephrine, and pectin were increased by approximately 26.0, 31.3, 44.8, 19.7, and 23.1%, respectively, compared to the untreated control. Collectively, these results indicated that, as a biostimulant, preharvest application of P. fluorescens ZX is an effective, affordable, ecological, and ecofriendly alternative agricultural technique for exploiting citrus crops. This approach is also promising for increasing the value of citrus fruit peel (currently regarded primarily as processing waste), thereby allowing industrial agricultural practices to move one step closer toward a circular economy.

Potential of Volatile Organic Compounds Emitted by Pseudomonas fluorescens ZX as Biological Fumigants to Control Citrus Green Mold Decay at Postharvest.

In this study, volatile organic compounds (VOCs) were generated by Pseudomonas fluorescens ZX with incubation in nutrient broth (NB), on NA (NB with agar), and on healthy orange fruits, and pure individual components of VOCs were used to manage citrus green mold infected by Penicillium digitatum. At a concentration of 1 × 1010 cfu/mL, the VOCs from antagonist-containing NA plates inhibited P. digitatum conidial germination and mycelial growth by about 60%, while the VOCs from bacterial fluid exhibited approximately 75% inhibitory effect. Biofumigation by VOCs significantly reduced the disease index, with a higher biocontrol efficacy by VOCs from bacterial fluid (about 51%) than from antagonist-containing NA plates (around 40%) or from antagonist-infested fruit (approximately 24%). Exposure to VOCs led to morphological abnormalities of P. digitatum conidia and hyphae. However, VOCs exhibited poor preventative and curative action against P. digitatum. The storage test showed that biofumigation had no negative effects on fruit quality. Antifungal assays suggested that dimethyl disulfide and dimethyl trisulfide exhibited the highest inhibitory effects, which afforded complete inhibition at the lowest concentrations. In addition, organic acids were also promising in controlling green mold, but only at suitable low concentrations to avoid eliciting fruit's physiological diseases.

Insights into the stability of carotenoids and capsaicinoids in water-based or oil-based chili systems at different processing treatments.

Ultrasonication, microwave, heat, and light treatments, as well as storage conditions, were investigated for their effects on the stability of carotenoids and capsaicinoids in water/oil chili systems. The stability of carotenoids and capsaicinoids were found to vary in response to different processing treatments. Carotenoid and capsaicinoid contents in chili juice (CJ, water system) were increased by low-power ultrasonic and microwave treatments, but decreased by high-power treatments. The thermal stability of carotenoids and capsaicinoids in hot pot bottom (HPB, oil system) were superior to those in CJ. Moreover, ultraviolet light significantly reduced the contents of carotenoids and capsaicinoids in both CJ and HPB. It was also demonstrated that low temperature conditions (4 °C) significantly delayed the degradation of carotenoids and capsaicinoids in chili-based food. In conclusion, our findings suggest that the stability of carotenoids and capsaicinoids can be tuned using different processing and storage techniques appropriate to different systems.

Lactobacillus plantarum KFY02 enhances the relieving effect of gardenoside on montmorillonite induced constipation in mice.

Lactobacillus plantarum KFY02 (KFY02), isolated from naturally fermented milk yoghurt in Korla, Xinjiang, Northwest of China, showed gardenoside action for the intestinal regulation of constipated mice. Comparatively, the effects of KFY02 (0.5 × 108 CFU kg-1, by body weight (BW)), gardenoside (50 mg kg-1, BW), and KFY02 (0.5 × 108 CFU kg-1, BW) + gardenoside (50 mg kg-1, BW) on intestinal regulation in mice with montmorillonite-induced constipation were also studied. Enzyme linked immunoassay, hemotoxylin and eosin (H&E) staining, quantitative polymerase chain reaction (qPCR) assay and high performance liquid chromatography (HPLC) analysis were used for the study. Compared with the model group, KFY02 + genipin (combined group) increased the propelling rate of activated carbon in the small intestines of mice and accelerated the discharge of the first black stool in mice. At the same time, the combination group reduced the levels of motilin (MTL), substance P (SP) and endothelin-1 (ET-1) in the serum, and increased the somatostatin (SS), vasoactive intestinal peptide (VIP), acetylcholinesterase (AchE) and gastrin (Gastrin) levels in the serum, which made these parameters close to those of the normal group. Using qPCR analysis, it was observed that the combined group up-regulated the mRNA expression of endothelial nitric oxide synthase (eNOS), stem cell factor (SCF), stem cell factor receptor (c-Kit), glutathione (GSH), catalase and manganese-superoxide dismutase (Mn-SOD) and down-regulated the expression of inducible nitric oxide synthase (iNOS) and transient receptor potential vanilloid receptor 1 (TRPV1). The combination increased the Bacteroides and Akkermansia abundances and decreased the Firmicutes abundance in the feces of the constipated mice and decreased the Firmicutes/Bacteroides ratio. The expression of the above genes was similar to that of the normal group. The results indicate that KFY02 produced ß-glucosidase to hydrolyze the gardenoside glycosidic bond to produce genipin and can effectively promote the regulation of gastrointestinal hormones and intestinal peristalsis and reduce oxidative tissue damage in constipated mice. This study also confirmed that KFY02 has similar relieving effects to gardenoside for constipation in mice.

Potential modes of action of Pseudomonas fluorescens ZX during biocontrol of blue mold decay on postharvest citrus.

BACKGROUND: The application of chemical fungicides is currently the main method for the control of postharvest decay of fruits and vegetables. However, public concern has been growing towards the effect of fungicides on food safety, human health and environmental pollution. Thus, interest in microbial biocontrol agent development has grown, such agents being considered both safe and environmentally friendly. Pseudomonas fluorescens is widely distributed in nature, and one of the most valuable biocontrol and plant growth-promoting rhizobacteria. In this study, the efficacy and the potential associated modes of action of P. fluorescens ZX against Penicillium italicum on oranges (Citrus sinensis Osbeck) were investigated. RESULTS: The application of P. fluorescens ZX significantly reduced blue mold lesion size and incidence in comparison to the control, where P. fluorescens ZX was effective when applied preventatively but not curatively. In dual cultures, treatment with cell-free autoclaved cultures or culture filtrate had a limited capacity to suppress P. italicum, while P. italicum was inhibited by bacterial fluid and bacterial suspension with living cells in vitro. The P. fluorescens ZX isolate displayed protease, but not chitinase, glucanase or cellulose, activity, and produced siderophores and volatile organic compounds with antifungal abilities. Competition tests showed P. fluorescens ZX could use fructose, sucrose, aspartic acid, threonine, serine, glycine, valine, lysine and proline better than P. italicum. Furthermore, an effective biofilm that peaked after a 24-hour incubation at 30 °C was formed by the P. fluorescens ZX isolate. Light microscopy and scanning electron microscopy observations indicate the P. fluorescens ZX isolate could not undergo direct parasitism or hyperparasitism. CONCLUSIONS: Competition for nutrients and niches, biofilm formation, inhibition of spore germination and mycelial growth, and production of inhibitory metabolites may play important roles in P. fluorescens ZX antagonism of P. italicum. © 2019 Society of Chemical Industry.

Lactobacillus plantarum CQPC02-Fermented Soybean Milk Improves Loperamide-Induced Constipation in Mice.

This study determined the ameliorative effects of the novel microorganism, Lactobacillus plantarum CQPC02 (LP-CQPC02), fermented in soybean milk, on loperamide-induced constipation in Kunming mice. High-performance liquid chromatography revealed that LP-CQPC02-fermented soybean milk (LP-CQPC02-FSM) had six types of soybean isoflavones, whereas Lactobacillus bulgaricus-fermented soybean milk (LB-FSM) and unfermented soybean milk (U-FSM) only had five types of soybean isoflavones. LP-CQPC02-FSM also contained more total and active soybean isoflavones than LB-FSM and U-FSM. Results from mouse experiments showed that the defecation factors (quantity, fecal weight and water content, gastrointestinal transit ability, and time to first black stool) in the LP-CQPC02-FSM-treated mice were better than those in the LB-FSM- and U-FSM-treated mice. The serum and small intestinal tissue experiments showed that soybean milk increased the motilin, gastrin, endothelin, acetylcholinesterase, substance P, vasoactive intestinal peptide, and glutathione levels and decreased the somatostatin, myeloperoxidase, nitric oxide, and malondialdehyde levels compared with the constipated mice in the control group. The LP-CQPC02-FSM also showed better effects than those of LB-FSM and U-FSM. Further results showed that LP-CQPC02-FSM upregulated cuprozinc-superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), catalase (CAT), c-Kit, stem cell factor (SCF), glial cell-derived neurotrophic factor (GDNF), neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), and aquaporin-9 (AQP9) and downregulated the expression levels of transient receptor potential cation channel subfamily V member 1 (TRPV1), inducible nitric oxide synthase (iNOS), and aquaporin-3 (AQP3) in the constipated mice. LP-CQPC02-FSM increased the Bacteroides and Akkermansia abundances and decreased the Firmicutes abundance in the feces of the constipated mice and decreased the Firmicutes/Bacteroides ratio. This study confirmed that LP-CQPC02-FSM partially reversed constipation in mice.

Protective effect of Lactobacillus fermentum CQPC04 on dextran sulfate sodium-induced colitis in mice is associated with modulation of the nuclear factor-κB signaling pathway.

Colitis severely affects the quality of life of patients, and lactic acid bacteria have been reported to be able to improve or treat colitis. In this study, we selected a strain of Lactobacillus fermentum (CQPC04) with good resistance in vitro to evaluate its effect on improvement in mice with dextran sulfate sodium (DSS)-induced colitis. We analyzed the effects of L. fermentum CQPC04 on mice with colitis macroscopically via colon length and histopathology. We also used conventional biochemical and ELISA kits, real-time quantitative PCR (RT-qPCR), and Western blotting to analyze microscopically the effects of L. fermentum CQPC04 on related oxidant indices and pro- and anti-inflammatory cytokines in serum and colon tissue of mice. The results indicated that L. fermentum CQPC04 notably increased colon length and ameliorated pathological damage of colon tissue in colitic mice. Serum indices showed that L. fermentum CQPC04 increased the enzyme activity of total superoxide dismutase (T-SOD) and catalase (CAT) and decreased the content of malondialdehyde (MDA) and the activity of myeloperoxidase (MPO). In addition, it inhibited the release of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), IFN-γ, IL-1ß, IL-6, and IL-12, and increased the release of the anti-inflammatory cytokine IL-10 in serum. The RT-qPCR experiments confirmed that L. fermentum CQPC04 downregulated the expression of pro-inflammatory cytokine nuclear factor-κB-p65 (NF-κBp65), NF-κB inhibitor-α (IκB-α), TNF-α, IFN-γ, IL-1ß, IL-6, cyclooxygenase 2 (COX-2), and inducible nitric oxide synthase (iNOS), and upregulated the expression of IL-10 in colon tissue. Western blot analysis indicated that L. fermentum CQPC04 significantly reduced expression of NF-κBp65, TNF-α, IL-1ß, COX-2, and iNOS in mouse colon tissues, and increased expression of IκB-α and superoxide dismutase 2 (SOD2). Thus, L. fermentum CQPC04 could effectively alleviate the symptoms of DSS-induced colitis mice and is a potential probiotic for human experiments.

Effects of Lactobacillus plantarum CQPC01-fermented soybean milk on activated carbon-induced constipation through its antioxidant activity in mice.

A newly found strain, Lactobacillus plantarum CQPC01 (LP-CQPC01), was used for soybean milk fermentation, and its effects against constipation were determined. LP-CQPC01-FSM (LP-CQPC01-fermented soybean milk) was found to have six kinds of soybean isoflavones; the isoflavones of LP-CQPC01-FSM were more than those of Lactobacillus bulgaricus-fermented soybean milk (LB-FSM) and unfermented soybean milk (U-FSM). Animal experiment showed that the MTL, Gas, ET, AchE, SP, VIP, and GSH levels in the constipated mice were increased; however, the SS, MPO, NO, and MDA levels in the constipated mice were reduced by soybean milk treatment. Further, LP-CQPC01-FSM increased the mRNA and protein expression of Cu/Zn-SOD, Mn-SOD, CAT, c-Kit, SCF, and GDNF and reduced the expression of TRPV1 and NOS relative to those of the mice with untreated constipation. LP-CQPC01 could be used as a new starter to produce high-quality soybean milk, which might be used as a functional drink.

Effects of Pulsed Electric Field (PEF) Treatment on Enhancing Activity and Conformation of α-Amylase.

To explore an efficient, safe, and speedy application of pulsed electric field (PEF) technology for enzymatic modification, effects of PEF treatment on the enzymatic activity, property and kinetic parameters of α-amylase were investigated. Conformational transitions were also studied with the aid of circular dichroism (CD) and fluorescence spectra. The maximum enzymatic activity of α-amylase was obtained under 15 kV/cm electric field intensity and 100 mL/min flow velocity PEF treatment, in which the enzymatic activity increased by 22.13 ± 1.14% compared with control. The activation effect could last for 18 h at 4 °C. PEF treatment could widen the range of optimum temperature for α-amylase, however, it barely exerted any effect on the optimum pH. On the other hand, α-amylase treated by PEF showed an increase of Vmax, t1/2 and ΔG, whereas a decrease of Km and k were observed. Furthermore, it can be observed from fluorescence and CD spectra that PEF treatment had increased the number of amino acid residues, especially that of tryptophan, on α-amylase surface with enhanced α-helices by 34.76% and decreased random coil by 12.04% on α-amylase when compared with that of untreated. These changes in structure had positive effect on enhancing α-amylase activity and property.

Preventive Effect of Lactobacillus fermentum Zhao on Activated Carbon-Induced Constipation in Mice.

The aim of this study was to investigate the effects of Lactobacillus fermentum Zhao (LF-Zhao) on activated carbon-induced constipation in ICR mice. ICR mice were administered lactic acid bacteria by gavage for 9 d. Body weight, diet intake, drinking amount, stool status, gastrointestinal transit distance and stool time, in addition to motilin (MTL), gastrin (Gas), endothelin (ET), somatostatin (SS), acetylcholinesterase (AChE), substance P (SP) and vasoactive intestinal peptide (VIP) levels in serum were monitored to evaluate the preventive effects of LF-Zhao on constipation. Bisacodyl, a laxative drug, was used as a positive control. Times to the first black stool for normal (untreated), control (no lactic acid bacteria treatment but activated carbon treated), bisacodyl-treated and L. delbrueckii subsp. bulgaricus (LB), LF-Zhao (L) (low concentration of 1×10(8) CFU/mL)- and LF-Zhao (H) (high concentration of 1×10(9) CFU/mL)-treated mice induced by activated carbon were 90, 218, 117, 180, 169 and 156 min, respectively. Following the consumption of LB, LF-Zhao (L) and LF-Zhao (H) or the oral administration of bisacodyl, the gastrointestinal transit distances were reduced by 55.2%, 61.3%, 70.6% and 94.6%, respectively. The serum levels of MTL, Gas, ET, AChE, SP and VIP were significantly increased and the serum levels of SS were reduced in the mice treated with LF-Zhao compared with those in the control mice (p<0.05). These results demonstrated that lactic acid bacteria demonstrate preventive effects on mouse constipation and that LF-Zhao alleviated constipation symptoms better than LB.

Preventive effect of Lactobacillus fermentum Lee on activated carbon-induced constipation in mice.

The aim of this study was to investigate the effects of Lactobacillus fermentum Lee (LF-Lee) on activated carbon-induced constipation in ICR mice. ICR mice were orally administered lactic acid bacteria for nine days. Body weight, dietary and water intake, defecation status, gastrointestinal (GI) transit and defecation time, as well as levels of motilin (MTL), gastrin (Gas), endothelin (ET), somatostatin (SS), acetylcholinesterase (AChE), substance P (SP) and vasoactive intestinal peptide (VIP) in serum were measured to evaluate the preventive effects of LF-Lee on constipation. Bisacodyl, a laxative drug, was administered as a positive control. The time taken until the first defecation of a black stool for normal, control, bisacodyl- (100 mg/kg, oral administration), Lactobacillus bulgaricus (LB)-, LF-Lee low dose (L)- and LF-Lee high dose (H)-treated mice was 90, 218, 117, 180, 161 and 151 min, respectively. Following the consumption of LB, LF-Lee (L) or LF-Lee (H), or the oral administration of bisacodyl, the GI transit was reduced to 55.2, 65.8, 73.1 and 94.6%, respectively, of the transit in normal mice. The serum levels of MTL, Gas, ET, AChE, SP and VIP were significantly increased and those of SS were reduced in the mice treated with LF-Lee compared with those in the untreated control mice (P<0.05). These results demonstrate that lactic acid bacteria have preventive effects on constipation in mice and that LF-Lee has superior functional activity.