ABSTRACT
Adlay bran is known for its nutrient-rich profile and multifunctional properties, and steam explosion (SE) is an emerging physical modification technique. However, the specific effects of SE on the activity composition and antioxidant capacity of adlay bran soluble dietary fiber (SDF) during in vitro digestion, as well as its influence on gut microbiota during in vitro fermentation, remain inadequately understood. This paper reports the in vitro digestion and fermentation characteristics of soluble dietary fiber from adlay bran modified by SE (SE-SDF). Compared with the untreated samples (0-SDF), most of the phenolic compounds and antioxidant capacity were significantly increased in the SE-SDF digests. Additionally, SE was beneficial for adlay bran SDF to increase the content of acetic acid, propionic acid and total short-chain fatty acids (SCFAs) in fermentation broth during in vitro fermentation. SE-SDF could promote the growth of beneficial bacteria while inhibiting the proliferation of pathogenic microbes. Our research indicates that SE-SDF shows strong antioxidant properties after in vitro digestion and plays a pivotal role in regulating gut microbiota during in vitro fermentation, ultimately enhancing human intestinal health.
Subject(s)
Antioxidants , Coix , Dietary Fiber , Digestion , Fatty Acids, Volatile , Fermentation , Gastrointestinal Microbiome , Steam , Dietary Fiber/metabolism , Gastrointestinal Microbiome/physiology , Antioxidants/metabolism , Antioxidants/analysis , Fatty Acids, Volatile/metabolism , Fatty Acids, Volatile/analysis , Coix/chemistry , Humans , Propionates/metabolism , Food Handling/methodsABSTRACT
Carbon frameworks with well-developed porosity present broad application prospects in energy-related materials, and green preparation still face challenges. Herein, the tannins-derived framework-like carbon material is obtained by cross-linking and self-assembly strategy.The phenolic hydroxyl and quinones in tannin cross-linking react with the amine groups in the methenamine by simple stirring, which drives the self-assembly of tannins and methenamine,contributing to the reaction products being precipitated in solution as aggregates with framework-like structure. The porosity and micromorphology of framework-like structures are further enriched by the thermal stability difference between tannin and methenamine. The methenamine of framework-like structures is entirely removed by the sublimation and decomposition and the tannin is transformed into carbon materials inheriting framework-like structures after the carbonization, which offers the path for rapid electron transport. The framework-like structure, excellent specific surface area and nitrogen doping give the assembled Zn-ion hybrid supercapacitors a superior specific capacitance of 165.3 mAh·g-1 (350.4 F·g-1). This device could be charged to 1.87 V to power the bulb by using solar panels. This study proves that the tannin-derived framework-like carbon is a promising electrode of the Zn-ion hybrid supercapacitors, which is beneficial for value-added and industrial supercapacitors application of green feedstocks.
ABSTRACT
BACKGROUND: Two years into the COVID-19 pandemic and with more than five million deaths worldwide, the healthcare establishment continues to struggle with every new wave of the pandemic resulting from a new coronavirus variant. Research has demonstrated that there are variations in the symptoms, and even in the order of symptom presentations, in COVID-19 patients infected by different SARS-CoV-2 variants (e.g., Alpha and Omicron). Textual data in the form of admission notes and physician notes in the Electronic Health Records (EHRs) is rich in information regarding the symptoms and their orders of presentation. Unstructured EHR data is often underutilized in research due to the lack of annotations that enable automatic extraction of useful information from the available extensive volumes of textual data. METHODS: We present the design of a COVID Interface Terminology (CIT), not just a generic COVID-19 terminology, but one serving a specific purpose of enabling automatic annotation of EHRs of COVID-19 patients. CIT was constructed by integrating existing COVID-related ontologies and mining additional fine granularity concepts from clinical notes. The iterative mining approach utilized the techniques of 'anchoring' and 'concatenation' to identify potential fine granularity concepts to be added to the CIT. We also tested the generalizability of our approach on a hold-out dataset and compared the annotation coverage to the coverage obtained for the dataset used to build the CIT. RESULTS: Our experiments demonstrate that this approach results in higher annotation coverage compared to existing ontologies such as SNOMED CT and Coronavirus Infectious Disease Ontology (CIDO). The final version of CIT achieved about 20% more coverage than SNOMED CT and 50% more coverage than CIDO. In the future, the concepts mined and added into CIT could be used as training data for machine learning models for mining even more concepts into CIT and further increasing the annotation coverage. CONCLUSION: In this paper, we demonstrated the construction of a COVID interface terminology that can be utilized for automatically annotating EHRs of COVID-19 patients. The techniques presented can identify frequently documented fine granularity concepts that are missing in other ontologies thereby increasing the annotation coverage.
Subject(s)
COVID-19 , Electronic Health Records , Humans , Pandemics , SARS-CoV-2ABSTRACT
OBJECTIVE: Gut microbiota dysbiosis is closely linked to the pathogenesis of rheumatoid arthritis (RA). We aimed to identify potential probiotic gut microbes that can ameliorate the development of RA. DESIGN: Microbiota profiling in patients with RA and healthy individuals was investigated via 16S rDNA bacterial gene sequencing and shotgun metagenomics. Collagen-induced arthritic mice and TNF-α transgenic mice were used to evaluate the roles of the gut commensal Parabacteroides distasonis in RA. The effects of P. distasonis-derived microbial metabolites on the differentiation of CD4+ T cells and macrophage polarisation were also investigated. RESULTS: The relative abundance of P. distasonis in new-onset patients with RA and patients with RA with history of the disease was downregulated and this decrease was negatively correlated with Disease Activity Score-28 (DAS28). Oral treatment of arthritic mice with live P. distasonis (LPD) considerably ameliorated RA pathogenesis. LPD-derived lithocholic acid (LCA), deoxycholic acid (DCA), isolithocholic acid (isoLCA) and 3-oxolithocholic acid (3-oxoLCA) had similar and synergistic effects on the treatment of RA. In addition to directly inhibiting the differentiation of Th17 cells, 3-oxoLCA and isoLCA were identified as TGR5 agonists that promoted the M2 polarisation of macrophages. A specific synthetic inhibitor of bile salt hydrolase attenuated the antiarthritic effects of LPD by reducing the production of these four bile acids. The natural product ginsenoside Rg2 exhibited its anti-RA effects by promoting the growth of P. distasonis. CONCLUSIONS: P. distasonis and ginsenoside Rg2 might represent probiotic and prebiotic agents in the treatment of RA.
Subject(s)
Arthritis, Rheumatoid , Mice , Animals , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/metabolism , Bacteroidetes , BacteriaABSTRACT
Fructo-oligosaccharides (FOS) have well-known bifidogenic effects as probiotics. In this study, esterification was adopted for FOS modification to produce better prebiotic properties. We synthesized and characterized acetylated fructo-oligosaccharides (Ac-FOS) and butyrylated fructo-oligosaccharides (Bu-FOS) as candidate prebiotics. Antioxidant activity and prebiotic esactiviti were evaluated as important indicators. We found, surprisingly, that butyrylation was an effective method in significantly improving the antioxidant activity of FOS. The fermentation products of feces from mice added to Ac-FOS and Bu-FOS, were investigated in vitro, including changes of pH values, short-chain fatty acids (SCFAs) production, and microbiota composition. Supplementation of Ac-FOS or Bu-FOS increased pH values and promoted the growth and activity of beneficial intestinal bacteria, such as Bifidobacteria and Lactobacillus. More importantly, the levels of prebiotic SCFAs were obviously elevated as detected by Gas Chromatography-Mass Spectrometry (GC-MS). Results suggest that Ac-FOS and Bu-FOS have great potential applications in SCFA delivery systems and gut microbiota regulation.
ABSTRACT
The application of biomass-based carbon materials in electrode materials are usually subject to their deficient adsorption sites as well as sluggish diffusion of electrolyte ions. Herein, flower-like carbons are obtained from the heavy fraction of bio-oil with the auxiliary of Hydrogen-bonded frameworks (HOFs) crystals. During the co-carbonization of the both, the HOFs crystals are removed on account of its poor stability, which directs the formation of flower-like morphology and generates the penetrable meso/macropores across petal-like carbon nanosheets. In addition, the pyrolysis gases serve as the agents for activation to enrich the active sites without the further activation. The degree of graphitization and the contents of pyridine nitrogen for carbon materials could be flexibly adjusted with the contents of HOFs. Owing to the beneficial 3D flower-like structure, high specific surface area (1076 m2/g), large pore volume (2.59 cm3/g), and rational N species, the assembled Zn//BH-4 hybrid supercapacitor reaches a superior energy density of 117.5 Wh/kg at 890 W/kg and maintains 60.7 Wh/kg even at 16.2 kW/kg.
Subject(s)
Carbon , Hydrogen , Electric Capacitance , Ions , Plant Oils , Polyphenols , ZincABSTRACT
The present study was done to evaluate the prebiotic effect of Lycium barbarum polysaccharide (LBP), its effect on murine fecal microbiota composition and innate immune response. Results showed that LBP supports the growth of selective probiotic bacteria with a maximum of 8.23 (log10 cfu/mL) and 6.62 (log10 cfu/mL) for Lactobacillus acidophilus and Bifidobacterium longum respectively. In vivo studies revealed that the administrations of LBP to mice resulted in an increase in the abundance of the phyla Proteobacteria and Firmicutes, while reducing the ratio of the phylum Bacteroidetes. At the genus level, the administration of LBP stimulated the emergence of some potential probiotic genera (Akkermansia, Lactobacillus, and Prevotellaceae). The concentrations of TGF-ß and IL-6 in serum and sIgA in the colon content were enriched significantly after LBP administrations in mice. The thymus index and spleen index of mice treated with LBP displayed significant difference compared to the control group (Pâ¯<â¯0.05). These findings suggest that LBP is a good source as a potential prebiotic and can enhance the intestinal microbiota and boost beneficial bacteria levels, modulate innate immune response.
Subject(s)
Adjuvants, Immunologic/administration & dosage , Drugs, Chinese Herbal/administration & dosage , Gastrointestinal Microbiome/drug effects , Gastrointestinal Microbiome/physiology , Prebiotics/administration & dosage , Animals , Cytokines/immunology , Cytokines/metabolism , Mice , Random Allocation , Spleen/drug effects , Spleen/immunology , Spleen/metabolism , Thymus Gland/drug effects , Thymus Gland/immunology , Thymus Gland/metabolismABSTRACT
Bacterial hemorrhagic septicemia caused by multi-drug resistant (MDR) Aeromonas hydrophila has exponentially increased in the past decade, and reached an alarming rate making it a major concern in the aquaculture industry in China. The aim of this study was to investigate the difference in the regulation of proteins expression in multi-drug resistance and susceptible A. hydrophila strains isolated from diseased fish using two-dimensional electrophoresis (2-DE) combined with mass spectrometry. 28 isolates of A. hydrophila were successfully identified by biochemical tests. Antibiotic susceptibility test results showed that all the isolates have different drug resistant patterns. A total of 61 and 17 differently expressed proteins were identified in MDR and susceptible A. hydrophila, respectively, evidencing that biological processes related to carbon metabolism, biosynthesis of secondary metabolites, microbial metabolism in diverse environments, cationic antimicrobial peptide (CAMP) resistance and propanoate metabolism were down-regulated in MDR strain, while proteins involved in biosynthesis of antibiotics, glycolysis/gluconeogenesis were highly expressed in the sensitive strain. The analysis of differentially expressed proteins from multi-drug resistance and susceptible strains suggests that a number of proteins are involved in several metabolic metabolism pathways plays an important role in A. hydrophila drug resistance. Our findings provide new insights about mechanisms involved in drug resistance and propose possible novel targets for developing alternative antibacterial drugs.
Subject(s)
Aeromonas hydrophila/drug effects , Bacterial Proteins/chemistry , Fish Diseases/microbiology , Gram-Negative Bacterial Infections/veterinary , Aeromonas hydrophila/chemistry , Aeromonas hydrophila/genetics , Aeromonas hydrophila/metabolism , Animals , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Drug Resistance, Multiple, Bacterial , Electrophoresis, Gel, Two-Dimensional , Fishes , Gene Expression Regulation, Bacterial , Gram-Negative Bacterial Infections/microbiology , Mass Spectrometry , ProteomicsABSTRACT
BACKGROUND: In natural environments, bacteria always live in communities with others where their physiological characteristics are influenced by each other. Bacteria can communicate with one another by using autoinducers. The current knowledge on the effect of quenching bacteria on others is limited to assess the impact of quorum-quenching bacterium Bacillus sp. QSI-1 on proteins pattern and virulence factors production of Aeromonas hydrophila YJ-1. Proteomic analysis was performed to find out protein changes and virulence factors, after 24 h co-culture. RESULTS: Results showed that several proteins of A. hydrophila YJ-1 were altered, seventy-two differentially expressed protein spots were excised from 2-DE gels and analyzed by MALDI-TOF/TOF MS, resulting in 63 individual proteins being clearly identified from 70 spots. Among these proteins, 50 were divided into 22 classes and mapped onto 18 biological pathways. Mixed-culture growth with Bacillus sp. QSI-1 resulted in an increase of A. hydrophilia proteins involved in RNA polymerase activity, biosynthesis of secondary metabolites, flagellar assembly, and two-component systems. In contrast, mixed culture resulted in a decreased level of proteins involved in thiamine metabolism; valine, leucine and isoleucine biosynthesis; pantothenate and CoA biosynthesis. In addition, the two extracellular virulence factors, proteases and hemolysin, were significantly reduced when A. hydrophila was co-cultured with QSI-1, while only lipase activity was observed to increase. CONCLUSIONS: The information gathered from our experiment showed that Bacillus sp. QSI-1 has a major impact on the expression of proteins, including virulence factors of A. hydrophila.
Subject(s)
Aeromonas hydrophila/metabolism , Bacillus/physiology , Proteomics/methods , Quorum Sensing , Virulence Factors/metabolism , Bacterial Proteins/metabolism , Bacteriological Techniques , Coculture Techniques , Gene Expression Regulation, Bacterial , Hemolysin Proteins/metabolism , Lipase/metabolism , Peptide Hydrolases/metabolism , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Two-Dimensional Difference Gel ElectrophoresisABSTRACT
Stress hormones have been recently suggested to influence the pathogenicity of bacteria significantly. Stress has been identified as part of the factors causing an outbreak of infections in the aquaculture industry. The most studied neuroendocrine hormonal family from a microbial endocrinology perspective is the catecholamine comprising of norepinephrine, epinephrine, and dopamine. It is of importance that catecholamine affects the growth and virulence of bacteria. The influence of stress on bacterial infections is attributed to the ability of catecholamines to suppress the immune system as the mode of action for increased bacterial growth. Catecholamines have increased the growth of bacteria, virulence-associated factors, adhesions, and biofilm formation and consequently influence the outcome of infections by these bacteria in many hosts. The siderophores and the ferric iron transport system plays a vital role in the mechanism by which catecholamines stimulates growth and exposure of genes to stress hormones enhances the expression of genes involved in bacterial virulence. In recent years, it has been discovered that intestinal microflora takes part in bidirectional communication between the gut and brain. The rapidly growing field of microbiome research, understanding the communities of bacteria living within our bodies and the genes they contain is yielding new perspectives. This review reveals catecholamines effects on the growth and virulence of bacteria and the latest trends in microbial endocrinology.
Subject(s)
Bacteria/drug effects , Bacteria/growth & development , Bacterial Infections , Catecholamines/pharmacology , Aquaculture , Bacteria/genetics , Bacteria/pathogenicity , Bacterial Infections/microbiology , Biofilms/drug effects , Biofilms/growth & development , Catecholamines/chemistry , Dopamine/pharmacology , Endocrinology , Epinephrine/pharmacology , Gastrointestinal Microbiome/drug effects , Gene Expression Regulation, Bacterial/drug effects , Humans , Immune System , Norepinephrine/pharmacology , Quorum Sensing/drug effects , Virulence/drug effects , Virulence/genetics , Virulence Factors/geneticsABSTRACT
The objective of this study was to investigate the effect of dietary quorum quenching bacterium Bacillus cereus QSI-1 on skin mucus protein pattern and innate immune response in Crucian Carp (Carassius auratus gibelio). The differential proteomes of skin mucus of Crucian Carp were analyzed after administration of Bacillus cereus QSI-1 by isobaric tags for relative and absolute quantitation (iTRAQ) labeling, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 1974 proteins were quantified. Using a 1.5-fold change in expression as a physiological significant benchmark, 264 differentially expressed proteins were reliably quantified by iTRAQ analysis, including 130 up- and 134 down-regulated proteins after dietary Bacillus cereus QSI-1. Some Proteins that were involved in immunity included protein S100, annexin, histone H3, lymphocyte cytosolic protein 1, heat shock protein, L-plastin, keratin 91, etc. Furthermore, fish fed 5â¯×â¯108â¯CFU/g Bacillus cereus QSI-1 supplemented diet showed an increase in alternative complement activity and lysozyme activity but expressed a decrease in superoxide dismutase activity in skin mucus (Pâ¯<â¯0.05). However, administration of Bacillus cereus QSI-1 had no significant effects on total immunoglobulin level (Pâ¯>â¯0.05). These results demonstrated that dietary administration of Bacillus cereus QSI-1 affects skin mucus protein profile and innate immune response in Crucian Carp, and also can enhance the disease resistance of Crucian Carp against A. hydrophila. This is the first report on proteomics analysis of skin mucus proteins in Crucian Carp after administration of quorum quenching bacterium Bacillus cereus, and the results will help to understand the mucosal immune responses to probiotics at the protein level in fish.
Subject(s)
Bacillus cereus/chemistry , Carps/genetics , Carps/immunology , Fish Proteins/immunology , Immunity, Innate/genetics , Probiotics/pharmacology , Proteome/immunology , Animal Feed/analysis , Animals , Diet/veterinary , Female , Fish Proteins/genetics , Immunity, Humoral/genetics , Immunity, Mucosal/genetics , Male , Mucus/immunology , Skin/immunologyABSTRACT
In the present study, we evaluated the antibacterial and anti-quorum sensing qualities of phillyrin. The minimum inhibitory concentration (MIC) of phillyrin with regard to Pseudomonas aeruginosa is 0.5 mg/ml. The production of virulence factors-such as rhamnolipid (>78.69%), pyocyanin (>85.94%), and elastase (>89.95%)-that affect the pathogenicity of the P. aeruginosa strain PAO1 apparently declined in the presence of 0.25 mg/ml phillyrin. Biofilm formation decreased by 84.48%. In a Caenorhabditis elegans-Pseudomonas aeruginosa infection model, diseased worms lived longer (63.33%) in a phillyrin-containing medium than in a drug-free medium, and the drug did not directly kill the pathogen. Therefore, the present work suggests that phillyrin has potential as an antimicrobial agent for the control of infectious pathogens.
Subject(s)
Anti-Bacterial Agents/pharmacology , Glucosides/pharmacology , Pseudomonas aeruginosa/drug effects , Quorum Sensing/drug effects , Animals , Biofilms/drug effects , Caenorhabditis elegans/microbiology , Disease Models, Animal , Glycolipids/metabolism , Male , Pancreatic Elastase/metabolism , Pseudomonas Infections/drug therapy , Pseudomonas aeruginosa/metabolism , Pyocyanine/antagonists & inhibitorsABSTRACT
OBJECTIVE: Liuwei Dihuang (LWDH) is a famous traditional herbal medicine formula in China that may regulate the balance of kidney yin yang and has been used to restore functional insufficiency of the kidney for a long time in China. METHODS: In this study, the water extract of LWDH was tested for its α-Amylase and α-Glucosidase inhibitory activities, and its anti-diabetic property in streptozotocin (STZ)-induced diabetic mice was also analyzed. RESULTS: LWDH extract inhibited α-Glucosidase and α-Amylase activities in a dose- dependent manner. Treatment of streptozotocin-induced diabetic mice with LWDH extract decreased camp, fasting blood glucose, TC, TG, LDL-c, HbA1C, Urine volume levels and Urine sugar, increased HDL-c level when compared to STZ induced diabetic mice. CONCLUSION: This study demonstrates that extract of LWDH can inhibit α-amylase and α-glucosidase activities and shows anti-diabetic effect in a mice preclinical model.
Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Drugs, Chinese Herbal/pharmacology , Enzyme Inhibitors/pharmacology , Glycoside Hydrolase Inhibitors/pharmacology , Hypoglycemic Agents/pharmacology , alpha-Amylases/antagonists & inhibitors , Animals , Diabetes Mellitus, Experimental/chemically induced , Diabetes Mellitus, Experimental/metabolism , Female , Male , Mice , Mice, Inbred C57BL , Streptozocin , alpha-Amylases/metabolism , alpha-Glucosidases/metabolismABSTRACT
We report on the isolation and characterization of an acid- and bile-tolerant bacterial strain, Bacillus sp. YB1701 with antibacterial and quorum-quenching activity. Strain YB1701 was isolated from coastal sediment samples and characterized by biochemical tests and 16S rRNA sequencing. In vitro study indicated that strain YB1701 can survive at pH 2.0 for up to 3 h and tolerate bile up to 2.0% concentration even after 12 h of exposure. Strain YB1701 showed antimicrobial activity against fish pathogens Aeromonas hydrophila and Vibrio parahemolyticus using an agar well diffusion assay. The trial test showed dietary supplementation of YB1701 significantly improved the resistance of Carassius auratus gibelio against A. hydrophila challenge. The safety assessment revealed that the isolate Bacillus sp. YB1701 was not cytotoxic to Carassius auratus gibelio or mice and did not exhibit hemolytic activity on rabbit blood agar plate. Disc-diffusion assays using a panel of antibiotics listed by the European Food Safety Authority (EFSA) showed that YB1701 was susceptible to selected antibiotics. Under laboratory conditions, the degradation rate of organic waste (predominately fish excrement) for 14 days by YB1701 was 79.69%. Results from the present study suggest that strain YB1701 is a potential probiotic strain and can be used in aquaculture for degrading organic waste and improving disease resistance of fish against bacterial infection. Further study is needed to assess the utility of strain YB1701 on a commercial scale.
Subject(s)
Anti-Bacterial Agents/pharmacology , Aquatic Organisms/chemistry , Bacillus/chemistry , Fish Diseases/drug therapy , Probiotics/pharmacology , Aeromonas hydrophila/drug effects , Animal Feed , Animals , Anti-Bacterial Agents/chemistry , Aquaculture/methods , Bacteria/drug effects , Bacterial Infections/drug therapy , Quorum Sensing/drug effects , RNA, Ribosomal, 16S/genetics , Vibrio parahaemolyticus/drug effectsABSTRACT
Quorum sensing (QS) is a cell density dependent process that enables bacteria to communicate with each other based on the production, secretion and sensing of the auto-inducer molecules and then subsequently regulate virulence associated gene expression. Interrupting quorum sensing may represent a novel alternative approach to combat bacterial pathogen. Several bacteria can produce quorum quenching (QQ) enzymes. However, the role of QQ bacteria in shaping the microbiota and the level of N-acyl-homoserine lactones (AHLs, a prevalent type of QS molecules) producing bacteria remains largely unknown. The objective of this study was to examine the presence of AHLs in the fish intestine and investigate the modulation of gut microbiota and its effect on Aeromonas hydrophila level by a QQ enzyme producing probiotic Bacillus sp. QSI-1. AHLs were found in fish gut content and were confirmed in Aeromonas species using Chromobacterium violaceum CV026 and Agrobacterium tumefaciens AT 136 (pZLR4) as reporter strains. We demonstrated that the composition of fish gut microbiota was affected by quenching bacteria QSI-1, and the percentage of A. hydrophila was decreased significantly. Taken together, these results provide valuable insights into QQ enzyme producing probiotics can modulate the microbiota structure and decrease the percentage of AHL-producing pathogenic bacteria in the gut. These data strongly suggest that QQ probiotics may serve as non-antibiotic feed additive in aquaculture to control bacterial diseases.
Subject(s)
Aeromonas hydrophila/drug effects , Bacillus/metabolism , Gastrointestinal Microbiome/physiology , Goldfish/microbiology , Quorum Sensing/physiology , Acyl-Butyrolactones/metabolism , Aeromonas hydrophila/genetics , Aeromonas hydrophila/growth & development , Aeromonas hydrophila/metabolism , Agrobacterium tumefaciens/metabolism , Animals , Aquaculture/methods , Bacillus/enzymology , Bacillus/growth & development , DNA, Bacterial/analysis , Escherichia coli/drug effects , Escherichia coli/genetics , Female , Fish Diseases/diet therapy , Fish Diseases/microbiology , Lipase/metabolism , Male , Probiotics/pharmacology , Signal Transduction , Virulence Factors/metabolismABSTRACT
The repair of bone defects is still a pressing challenge in clinics. Injectable bone cement is regarded as a promising material to solve this problem because of its special self-setting property. Unfortunately, its poor mechanical conformability, unfavorable osteo-genesis ability and insufficient osteo-inductivity seriously limit its clinical application. In this study, novel experimental calcium phosphate silicate bone cement reinforced by carbon fibers (CCPSC) was fabricated and characterized. First, a compressive strength test and cell culture study were carried out. Then, the material was implanted into the femoral epiphysis of beagle dogs to further assess its osteo-conductivity using a micro-computed tomography scan and histological analysis. In addition, we implanted CCPSC into the beagles' intramuscular pouches to perform an elementary investigation of its osteo-inductivity. The results showed that incorporation of carbon fibers significantly improved its mechanical properties. Meanwhile, CCPSC had better biocompatibility to activate cell adhesion as well as proliferation than poly-methyl methacrylate bone cement based on the cell culture study. Moreover, pronounced biodegradability and improved osteo-conductivity of CCPSC could be observed through the in vivo animal study. Finally, a small amount of osteoid was found at the heterotopic site one month after implantation which indicated potential osteo-inductivity of CCPSC. In conclusion, the novel CCPSC shows promise as a bioactive bone substitute in certain load-bearing circumstances.
Subject(s)
Bone Cements/chemical synthesis , Bone Cements/therapeutic use , Calcium Phosphates/chemistry , Carbon/chemistry , Femoral Fractures/therapy , Osteogenesis/physiology , Animals , Carbon Fiber , Cells, Cultured , Compressive Strength , Dogs , Femoral Fractures/pathology , Male , Materials Testing , Polymethyl Methacrylate/chemistry , Silicates/chemistry , Silicates/therapeutic use , Treatment OutcomeABSTRACT
Pseudomonas aeruginosa is an opportunistic pathogen causing severe respiratory infections. Acylated homoserine lactones (AHLs) are self-generated diffusible signal molecules that mediate population density dependent gene expression (quorum sensing, QS) in a variety of Gram-negative bacteria, and several virulence genes of bacterial pathogens are known to be controlled by QS. Hence, fitness mutant of virulent factors is beneficial for natural selection. In this study, strains of P. aeruginosa isolated from chronic lung infection of cystic fibrosis patients, were screened for AHLs production by using indicator strains of Chromobacterium violaceum CV026 and Agrobacterium tumefaciens strain At136. Four AHLs defective strains were selected from fifty-three clinical isolates. PCR analysis revealed that only one isolate was negative for lasR gene. These four AHLs defective isolates produced less virulence factors and forming less biofilm than PAO1. Only isolate PA41 produce little more pyocyanin than PAO1. The results indicate that, despite the pivotal role of QS in the pathogenesis of P. aeruginosa infections, AHLs-deficient strains are still capable of causing infections in human.
ABSTRACT
Quorum Sensing (QS) is a bacterial regulatory mechanism, which is responsible for controlling the expression of various biological macromolecules such as the virulence factors in a cell density-dependent manner. Disruption of the QS system of pathogens has been proposed as a new anti-infective strategy. Biodegradation of AHLs proves to be an efficient way to interrupt QS, since AHLs are the main family of QS autoinducers used in Gram negative bacteria. In this study, the effect of Bacillus sp. QSI-1 as an efficient quorum quencher on virulence factors production and biofilm formation of fish pathogen Aeromonas hydrophila was investigated. QSI-1 reduced the accumulation of AHLs but did not affect the growth of A. hydrophila YJ-1 when cocultured. In the result, the supernatant of QSI-1 showed significant inhibition of protease production (83.9%), hemolytic activity (77.6%) and biofilm formation (77.3%) in YJ-1. In biocontrol experiment, QSI-1 significantly reduced the pathogenicity of A. hydrophila strain YJ-1 in zebrafish (Danio rerio). The fish fed with QSI-1 was observed to have a relative percentage survival of 80.8%. Our results indicate that AHLs degrading bacteria should be considered as an alternative for antibiotics in aquaculture for the biocontrol of bacterial fish diseases.
Subject(s)
Aeromonas hydrophila/physiology , Bacillus/physiology , Quorum Sensing/physiology , Zebrafish/microbiology , 4-Butyrolactone/analogs & derivatives , 4-Butyrolactone/metabolism , Aeromonas hydrophila/metabolism , Animals , Antibiosis , Biofilms/drug effects , Biofilms/growth & development , Culture Media, Conditioned/pharmacology , Hemolysis/drug effects , Host-Pathogen Interactions , Sheep , Virulence Factors/metabolismABSTRACT
Traditional Chinese herbal medicines (TCHMs) were tested for their ability of antiquorum sensing. Water extracts of Rhubarb, Fructus gardeniae, and Andrographis paniculata show antiquorumsensing activity when using Chromobacterium violaceum CV12472 as reporter; the sub-MIC concentrations of these TCHMs were tested against AHL-dependent phenotypic expressions of PAO1. Results showed significant reduction in pyocyanin pigment, protease, elastase production, and biofilm formation in PAO1 without inhibiting the bacterial growth, revealing that the QSI by the extracts is not related to static or killing effects on the bacteria. The results indicate a potential modulation of bacterial cell-cell communication, P. aeruginosa biofilm, and virulence factors by traditional Chinese herbal medicine. This study introduces not only a new mode of action for traditional Chinese herbal medicines, but also a potential new therapeutic direction for the treatment of bacterial infections, which have QSI activity and might be important in reducing virulence and pathogenicity of pathogenic bacteria.