Fecal fermentation and high-fat diet-induced obesity mouse model confirmed exopolysaccharide from Weissella cibaria PFY06 can ameliorate obesity by regulating the gut microbiota.

Obesity associated with diet and intestinal dysbiosis is a worldwide public health crisis, and exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) have prebiotic potential to ameliorate obesity. Therefore, the present study obtained LAB with the ability to produce high EPS, examined the structure of EPS, and explained its mechanism of alleviating obesity by in vivo and in vitro models. The results showed that Weissella cibaria PFY06 with a high EPS yield was isolated from strawberry juice, and pure polysaccharide (PFY06-EPS) was purified by Sephadex G-100. The structural characteristics of PFY06-EPS showed that the molecular weight was 8.08 × 106 Da and composed of α-(1,6)-D glucosyl residues. An in vitro simulated human colon fermentation test demonstrated that PFY06-EPS increased the abundance of Prevotella and Bacteroides. Cell tests confirmed that PFY06-EPS after fecal fermentation inhibited fat accumulation by promoting the secretion of endogenous gastrointestinal hormones and insulin and inhibiting the secretion of inflammatory factors. Notably, PFY06-EPS reduced weight gain, fat accumulation, inflammatory reactions and insulin resistance in a high-fat diet-induced obesity mouse model and improved glucolipid metabolism. PFY06-EPS intervention reversed obesity-induced microflora disorders, such as reducing the Firmicutes/Bacteroides ratio and increasing butyrate-producing bacteria (Roseburia and Oscillibacter), and reduced endotoxemia to maintain intestinal barrier integrity. Therefore, in vivo and in vitro models showed that PFY06-EPS had potential as a prebiotic that may play an anti-obesity role by improving the function of the gut microbiota.

Response characteristics of flax retting liquid addition during chicken manure composting: Focusing on core bacteria in organic carbon mineralization and humification.

To explore the applicability of flax retting liquid (FRL) addition, the physicochemical properties, microbial community structure and function, carbon conversion and humus (HS) formation were assessed during chicken manure (CM) aerobic composting. Compared with the control group, the addition of FRL increased the temperature at thermophilic phase, while the microbial mass carbon content (MBC) in SCF and FRH groups raised to 96.1 ± 0.25 g/Kg and 93.33 ± 0.27 g/Kg, respectively. Similarly, FRL also improved the concent of humic acid (HA) to 38.44 ± 0.85 g/Kg, 33.06 ± 0.8 g/Kg, respcetively. However, fulvic acid (FA) decreased to 30.02 ± 0.55 g/Kg, 31.4 ± 0.43 g/Kg, respectively and further reduced CO2 emissions. FRL influenced the relative abundance of Firmicutes at thermophilic phase and Ornithinimicrobium at maturity phase. Additionally, FRL strengthen the association among flora and reduce the number of bacteria, which was negative correlated with HA and positive with CO2 during composting. These findings offer powerful technological support for improving agricultural waste recycling.

Purification of exopolysaccharides from Lactobacillus rhamnosus and changes in their characteristics by regulating quorum sensing genes via polyphenols.

To explore the effect of Lonicera caerulea fruit polyphenols (LCP) on caries-causing bacteria, strain RYX-01 with high production of biofilm and exopolysaccharides (EPS) was isolated from the oral cavity of caries patients and was identified as Lactobacillus rhamnosus by 16S rDNA analysis and morphology. The characteristics of EPS produced by RYX-01 (EPS-CK) and those produced by adding L. caerulea fruit polyphenols (EPS-LCP) were compared to reveal whether LCP reduced the cariogenicity of RYX-01 by influencing the structure and composition of EPS. The results showed that LCP could increase the content of galactose in EPS and destroy the original aggregation state of EPS-CK but had no significant effect on the molecular weight and functional group composition of EPS (p > 0.05). At the same time, LCP could inhibit the growth of RYX-01, reduce EPS and biofilm formation and inhibit the expression of quorum sensing (QS, luxS)- and biofilm formation (wzb)-related genes. Therefore, LCP could change the surface morphology, content and composition of RYX-01 EPS and reduce the cariogenic effect of EPS and biofilm. In conclusion, LCP can be used as a potential plaque biofilm inhibitor and QS inhibitor in drugs and functional foods.

Aerobic composting with sauerkraut fermentation waste water: Increasing the stability and complexity of bacterial community and changing bacterial community assembly processes.

Aerobic composting renders the sauerkraut fermentation waste water harmless while adding soluble nutrients. Unravelling the bacterial community assembly processes, changes in community robustness and community cohesion and the relationship between them under composting treatment of sauerkraut fermentation waste water is an interesting topic. Sauerkraut fermentation waste water was used for composting, which increased bacterial linkages, community robustness, competitive behaviour during warming periods and cooperative behaviour during cooling periods, and the control of community assembly processes shifts from deterministic processes (variable selection) to stochastic processes (decentralised limitation). At the same time, the influence of community robustness and community cohesion on community assembly processes was increased. Community cohesion and robustness were significantly correlated with community function. These results indicate that community robustness and community cohesion are critical for the biological handling of hazardous substances.

Manganese dioxide eliminates the phytotoxicity of aerobic compost products and converts them into a plant friendly organic fertilizer.

This study mainly confirmed the exogenous substances (pomace, biochar, MnO2) and the quorum sensing of bacterial communities jointly regulate the metabolic conversion of toxic substances in manures and agricultural wastes, and converts them into a plant-friendly organic fertilizer through aerobic composting and pot experiment. The results showed the composting products had positive performance in bacterial communities, physicochemical indicators, and phytotoxicity. Meanwhile, the addition of exogenous substances could significantly improve seed germination index, promote metabolites conversion, and optimize bacterial community structure. Furthermore, the exogenous substances mainly regulated the functions of the three bacterial communities by quorum sensing system, then promoted the beneficial metabolites, and inhibited the harmful metabolites. Finally, pot experiments suggested compost products could significantly promote plant growth. Thus, these important discoveries extend the knowledge of the previous work and provide an economical and simple method to convert wastes into organic fertilizers that are friendly to plants and soil.

Evaluation of antioxidation, regulation of glycolipid metabolism and potential as food additives of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1.

At present, there are relatively few studies on the production of exopolysaccharide (EPS) by yeasts. Therefore, exploring the properties of EPS produced by yeast can not only enrich the source of EPS, but also play an important role in its future application in the food field. The aim of this study was to explore the biological activities of EPS (named SPZ) from Sporidiobolus pararoseus PFY-Z1, as well as the dynamic changes in physical and chemical properties that occur during simulated gastrointestinal digestion, and the effects of SPZ on microbial metabolites during fecal fermentation in vitro. The results revealed that SPZ had good water solubility index, water-holding capacity, emulsifying ability, coagulated skim milk, antioxidant properties, hypoglycemic activities, and bile acid-binding abilities. Furthermore, the content of reducing sugars increased from 1.20 ± 0.03 to 3.34 ± 0.11 mg/mL after gastrointestinal digestion, and had little effect on antioxidant activities. Moreover, SPZ could promote the production of short-chain fatty acids during fermentation for 48 h, in particular, propionic acid and n-butyric acid increased to 1.89 ± 0.08 and 0.82 ± 0.04 mmol/L, respectively. Besides this, SPZ could inhibit LPS production. In general, this study can help us to better understand the potential bioactivities, and the changes in bio-activities of compounds after digestion of SPZ.

Microbial communities that drive the degradation of flax pectin and hemicellulose during dew retting with Bacillus licheniformis HDYM-04 and Bacillus subtilis ZC-01 addition.

In this study, the combined addition of Bacillus licheniformis HDYM-04 and Bacillus subtilis ZC-01 to flax degradation increased the degradation rates of pectin (74.7 %) and pectinic acid (59.3 %) and increased the maximum activities of pectinase (610.66 ± 7.03 U/mL) and mannanase (656.97 ± 13.16 U/mL). 16S rRNA sequencing showed that the added bacterial agent (Bacillus) was the dominant bacterium, and its addition increased the relative abundance (RA) of Firmicutes and decreased the RA of Bacteroidetes. The core bacterial community linked to degradation (Firmicutes) was determined by RDA. Network analysis showed that the number of bacteria related to pectin and hemicellulose degradation increased with the addition of the bacteria combination. SEM analysis showed that Bacillus was positively correlated with the degradation of pectic substances. These results provide new ideas for improving the utilization of agricultural waste resources and promoting sustainable development in modern agriculture.

Production, characterization and antioxidant activity of exopolysaccharide from Sporidiobolus pararoseus PFY-Z1.

At present, the study on exopolysaccharid is mainly focused on lactic acid bacteria, and the research on exopolysaccharide produced by yeast, especially Sporidiobolus pararoseus, is relatively few. Therefore, the aim of this study was to explore the characterization and antioxidant activities of a novel neutral exopolysaccharide SPZ, which was isolated and purified from S. pararoseus PFY-Z1. The results showed that SPZ was mainly composed of mannose, followed by glucose, with a molecular weight was 24.98 kDa, had O-glycosidic bonds, no crystalline, and no triple helix structure. Based on fourier transform-infrared, high-performance liquid chromatography and nuclear magnetic resonance analyses, SPZ was identified to be a exopolysaccharide with some side chains, presence of α-, ß-pyranose ring and nine sugar residues. Furthermore, the morphology features of SPZ have performed a relatively rough and uneven surface, covered with small pores and fissures. Moreover, SPZ had higher antioxidant activities and the maximum scavenging abilities of ⋅OH, NO2- and reducing power were 28.05 ± 0.73%, 92.76 ± 1.86% and 0.345 ± 0.024, respectively. Hence, SPZ could be used as a potential antioxidant application in the food and pharmaceutical industries.

Aerobic composting of chicken manure with penicillin G: Community classification and quorum sensing mediating its contribution to humification.

Chicken manure containing antibiotics is a hazardous biological waste. The purpose of our study was to investigate how different concentrations of penicillin G alter the bacterial community to affect humification during aerobic composting of chicken manure. The effect of quorum sensing on the bacterial community was also evaluated. Penicillin G mainly affects low fold changes (within 4) for low-abundance (within 200) microbial genera. We found that the bacterial community cooperated to regulate humus and humic acid synthesis. The microbial genera that make up the bacterial community are different, but each bacterial community may have the same ecological function. Quorum sensing affects humic acid synthesis by regulating carbohydrate metabolism and amino acid metabolism in bacterial communities through mechanisms such as the pentose phosphate pathway and the shikimate pathway. This work presents an understanding of the impact of quorum sensing on the collaboration between bacterial communities during composting.

Analysis of the structure and properties of dextran produced by Weissella confusa.

An EPS produced by Weissella confusa H2 was purified through Sephadex G-100, and the preliminary structure characteristics and biological activities of H2 EPS were analyzed. Molecular mass of purified H2 EPS was 2.705 × 106 Da as measured with gel permeation chromatography (GPC). Composition of monosaccharides, nuclear magnetic resonance (NMR) spectroscopy spectroscopy and fourier transform infrared (FT-IR) showed that the EPS was a linear homopolysaccharide, mainly constituted of glucose and it is suggested that the EPS was dextran with α-(1 â†’ 6) glycosidic bonds and a few α-(1 â†’ 3) branches. Atomic force micrograph (AFM) and scanning electron microscopy (SEM) analysis of dextran further revealed sheets branched microstructure anchored with many irregular protuberances in aqueous solution. The XRD pattern reflected non-crystalline amorphous nature. In addition, the solubility, water-holding capacity, thermal property, rheological property and heavy metal chelating activity of the purified H2 dextran were determined. The dissolution percentage and water holding capacity of the dextran were 98.78 ± 1.37% and 426.03 ± 7.26%, respectively. The dextran exhibited good hydrophilicity, thermal stability and heavy metal chelating activity. Rheological studies exhibited rotational speed, pH, temperature, metal ions solutions dependent semiviscous nature. These results support its use as an additive in the food and environmental protection fields.

Driving factors of nitrogen conversion during chicken manure aerobic composting under penicillin G residue: Quorum sensing and its signaling molecules.

This study explored effects of different concentrations of penicillin G on nitrogen conversion, bacterial community composition, and quorum sensing during chicken manure aerobic composting. After composting, adding penicillin G down-regulated the abundance of 71 genera and up-regulated the abundance of 103 genera. These bacterial genera were mainly Firmicutes and Proteobacteria. 16S rRNA gene sequencing was employed for function prediction, and the results showed that the addition of penicillin G increased nitrification, reduced denitrification. The autoinducer-1 (AI-1), autoinducer-3 (AI-3) and Phr signal molecules further participated in the nitrogen cycle by regulating the population behavior among multiple bacterial genera. In addition, SEM analysis showed that the quorum sensing system negatively regulated the abundance of genus related to the nitrogen conversion during chicken manure aerobic composting. This is a new theoretical analysis of the research on the treatment of hazardous materials.

Optimization of cultivation strategy and medium for bacteriocin activity of Enterococcus faecium HDX-2.

A lactic acid bacteria (LAB) isolated from pickled Chinese cucumber was screened for bacteriocin production. The strain was identified to be Enterococcus faecium HDX-2. Based on the Plackett-Burman (PB) experiment, glucose, Ca2+, and initial pH were found to be the most significant parameters of bacteriocin production. Afterward, effects of the three main parameters on bacteriocin activity were further investigated by central composite design (CCD) and the optimum composition was glucose 22 g/L, Ca2+ 0.6 mM, and initial pH 7.2. Optimum results showed that bacteriocin activity was increased to 1337.60 ± 36.71 AU/mL, 2.23-fold higher than in MRS medium without parameters optimization. The bacteriocin also showed significant antimicrobial activity against Listeria monocytogenes in meat and cheese model system.

Intraspecific and interspecific quorum sensing of bacterial community affects the fate of antibiotic resistance genes during chicken manure composting under penicillin G stress.

In this study, the effects of penicillin G (PENG) on the fate of bacterial communities and ß-lactamase antibiotic resistance genes (ARGs) during chicken manure composting were assessed, to illustrate the roles of PENG in ARGs behavior. The results showed that the total absolute abundances of 9 ARGs and 4 mobile genetic elements (MGEs) was significantly increased by PENG (P < 0.05). Dozens of potential hosts for ARGs were predominantly affiliated with Firmicutes, Proteobacteria, and Actinobacteria. Meanwhile, the higher concentration of PENG significantly increased the abundance of luxI and luxS in quorum sensing (QS) (P < 0.05), which enhanced the frequency of inter/intraspecific gene "communication." Redundancy analysis and structural equation modeling further revealed that QS had a strong regulatory role in horizontal gene transfer of ARGs mediated via MGEs. These results provide new insight into the mechanism of ARGs propagation in aerobic composting modified by PENG.

Links between microbial compositions and metabolites during aerobic composting under amoxicillin stress was evaluated by 16S rRNA sequencing and gas chromatography-mass spectrometry: Benefit for the plant growth.

The purpose of this study was to identify the relationship between core bacteria and metabolites during aerobic composting and analyze the effects of metabolites on plant growth. The results revealed that amoxicillin might affect the generation and transformation of metabolites by reconstructs the bacterial communities. The peak area ratios (PAR) of esters and fatty acids (FAs) were increased, while sterols decreased during composting. Furthermore, the correlation analysis showed that the production of FAs, esters and sterols is strongly correlated with Oceanobacillus, Corynebacterium, Psychrobacter, Xanthomonadaceae, Pusillimonas and Gracilibacillus. Moreover, 36 key metabolites were screened out, the PAR of the propanoic acid ethyl ester and oleic acid that benefit plant growth were increased in amoxicillin groups. However, the PAR of environmental pollutants, such as n-hexadecanoic acid and 3ß, 5ß-Cholestan-3-ol is the opposite. Therefore, composting can eliminate the environmental risks caused by antibiotic residues in feces and promote plant growth.

Evaluation of nitrogen conversion pathway during composting under amoxicillin stress: Mainly driven by core microbial community.

The aim of this study was to explore the effects of different concentrations of amoxicillin (AMX) on nitrogen (N) conversion and bacterial community structure during aerobic composting. The results revealed that AMX led to a lower temperature and increased pH during the thermophilic phase of composting. AMX inhibited the relative abundance (RA) of Firmicutes at the initial phase but increased the RA of Actinobacteria and Bacteroidetes compared with the control treatment. The core bacterial community linked to N conversion was determined by network analysis. AMX decreased the RA of amoA, a gene related to nitrification, and increased the RAs of nirK and nosZ, which are related to denitrification. Meanwhile, AMX inhibited the activity of ammonia-oxidizing bacteria but promoted the activity of denitrifying bacteria. Therefore, the main adverse effect of AMX on compost quality is to change the microbial community structure and affect the physical and chemical properties of composting.

Large-scale advances in SSR markers with high-throughput sequencing in Euphorbia fischeriana Steud

BACKGROUND: Euphorbia fischeriana Steud is a very important medicinal herb and has significant medical value for healing cancer, edema and tuberculosis in China. The lack of molecular markers for Euphorbia fischeriana Steud is a dominant barrier to genetic research. For the purpose of developing many simple sequence repeat (SSR) molecular markers, we completed transcriptome analysis with the Illumina HiSeq 2000 platform. RESULTS: Approximately 9.1 million clean reads were acquired and then assembled into approximately 186.3 thousand nonredundant unigenes, 53,146 of which were SSR-containing unigenes. A total of 76,193 SSR loci were identified. Of these SSR loci, 28,491 were detected at the terminal position of ESTs, which made it difficult to design SSR primers for these SSR-containing sequences, and the residual SSRs were thus used to design primer pairs. Analyzing the results of these markers revealed that the mononucleotide motif A/T (44,067, 57.83% of all SSRs) was the most abundant, followed by the dinucleotide type AG/CT (9430, 12.38%). Using 100 randomly selected primer pairs, 77 primers were successfully amplified in Euphorbia fischeriana Steud, and 79 were successfully amplified in three other related species. The markers developed displayed relatively high quality and cross-species transferability. CONCLUSIONS: The large number of EST-SSRs exploited successfully in Euphorbia fischeriana Steud for the first time could provide genetic information for research on linkage maps, variety identification, genetic diversity analysis, and molecular marker-assisted breeding.

Purification and structural characterization and antioxidant activity of levan from Bacillus megaterium PFY-147.

An exopolysaccharide (EPS)-producing bacterial PFY-147 was separated from Hiqiher vineyard soil and determined as Bacillus megaterium by 16S rDNA analysis and morphological. The PFY-147-EPS was purified by gel-filtration chromatography. The average molecular weight (Mw) of purified EPS was 1.878 × 106 Da. The total carbohydrate contents, uronic acid and sulfated group content in PFY-147-EPS were found to be 90.37 ± 1.48%, 7.24 ± 0.36% and 2.39 ± 0.36%, respectively. The PFY-147-EPS was found to be a levan containing a backbone of 2,6-substituted ß-fructoses by high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopy. The atomic force microscopy (AFM) presented that the levan formed pointed or thorny structural in aqueous solution. Scanning electron microscopy (SEM) of the levan showed compact and nonuniform block sizes morphology. Moreover, the levan exhibited higher thermal stability with a degradation temperature of 265.63 °C in DSC analysis. The levan possessed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, Superoxide anion (O2-) radical, hydroxyl (OH) radical and and2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+) scavenging activities and strong metal ion chelating activity. The WHC and WSI of levan were 231.29 ± 3.76% and 97.34 ± 1.72%, respectively. These might have implications in food and medicine, as well as in pharmaceutical industries.