Patients with renal failure suffer from symptoms caused by uraemic toxins, possibly of gut microbial origin, as deduced from studies in animals. The aim of the study is to characterise relationships ...between the intestinal microbiome composition, uraemic toxins and renal failure symptoms in human end-stage renal disease (ESRD).
Characterisation of gut microbiome, serum and faecal metabolome and human phenotypes in a cohort of 223 patients with ESRD and 69 healthy controls. Multidimensional data integration to reveal links between these datasets and the use of chronic kidney disease (CKD) rodent models to test the effects of intestinal microbiome on toxin accumulation and disease severity.
A group of microbial species enriched in ESRD correlates tightly to patient clinical variables and encode functions involved in toxin and secondary bile acids synthesis; the relative abundance of the microbial functions correlates with the serum or faecal concentrations of these metabolites. Microbiota from patients transplanted to renal injured germ-free mice or antibiotic-treated rats induce higher production of serum uraemic toxins and aggravated renal fibrosis and oxidative stress more than microbiota from controls. Two of the species,
and
, increase uraemic toxins production and promote renal disease development in a CKD rat model. A probiotic
decreases abundance of these species, reduces levels of toxins and the severity of the disease in rats.
Aberrant gut microbiota in patients with ESRD sculpts a detrimental metabolome aggravating clinical outcomes, suggesting that the gut microbiota will be a promising target for diminishing uraemic toxicity in those patients.
This study was registered at ClinicalTrials.gov (NCT03010696).
Boron-doped helical carbon nanotubes (B-HCNTs) were obtained by annealing HCNTs under the boric oxide presence. The morphology and structure of HCNTs remained unchanged even after annealing and ...B-doping. HCNTs displayed excellent electromagnetic wave (EMW) absorption, judging by the corresponding optimal reflection loss and the absorption bandwidth values equal to − 47.86 dB and 3.20 GHz, respectively. Quick and straightforward synthesis process, excellent chemical stability and low density make our B-HCNTs promising as lightweight and efficient microwave absorbers.
The viable but nonculturable (VBNC) state is a survival strategy adopted by many pathogens when exposed to harsh environmental stresses. In this study, we investigated for the first time that whether ...high pressure CO2 (HPCD), one of the nonthermal pasteurization techniques, can induce Escherichia coli O157:H7 into the VBNC state. By measuring plate counts, viable cell counts and total cell counts, E. coli O157:H7 in 0.85% NaCl solution (pH 7.0) was able to enter the VBNC state by HPCD treatment at 5 MPa and four temperatures (25°C, 31°C, 34°C and 37°C). Meanwhile, with the improvement of treatment temperature, the time required for E. coli O157:H7 to enter VBNC state would shorten. Enzymatic activities in these VBNC cells were lower than those in the exponential-phase cells by using API ZYM kit, which were also reduced with increasing the treatment temperature, but the mechanical resistance of the VBNC cells to sonication was enhanced. These results further confirmed VBNC state was a self-protection mechanism for some bacteria, which minimized cellular energetic requirements and increased the cell resistance. When incubated in tryptic soy broth at 37°C, the VBNC cells induced by HPCD treatment at 25°C, 31°C and 34°C achieved resuscitation, but their resuscitation capabilities decreased with increasing the treatment temperature. Furthermore, electron microscopy revealed changes in the morphology and interior structure of the VBNC cells and the resuscitated cells. These results demonstrated that HPCD could induce E. coli O157:H7 into the VBNC state. Therefore, it is necessary to detect if there exist VBNC microorganisms in HPCD-treated products by molecular-based methods for food safety.
Boron-doped helical carbon nanotubes (B-HCNTs) were synthesized by annealing HCNTs under the boric acid presence. Successful B incorporation into the HCNT matrix was confirmed by the extensive ...characterization performed by field emission scanning, transmission electron microscopies, X-ray diffraction, Raman spectroscopy, as well as X-ray photoelectron spectroscopy. B doping did not damage the HCNT structures. However, B presence and content affected B-HCNT electrochemical performance, which was tested by cyclic voltammetry, galvanostatically, and by electrochemical impedance spectroscopy. The B-HCNTs demonstrated excellent energy storage performance, cycling stability, and specific capacitance equal to 212.6 F g
−1
at 1 A g
−1
. Thus, HCTN capacity was increased significantly after B doping.
This study investigated allergy immunotherapy potential of Lactobacillus paracasei L9 to prevent or mitigate the particulate matter 2.5 (PM2.5) enhanced pre-existing asthma in mice. Firstly, we used ...a mouse model of asthma (a 21-day ovalbumin (OVA) sensitization and challenge model) followed by PM2.5 exposure twice on the same day of the last challenge. PM2.5 was collected from the urban area of Beijing and underwent analysis for metals and polycyclic aromatic hydrocarbon contents. The results showed that PM2.5 exposure enhanced airway hyper-responsiveness (AHR) and lead to a mixed Th2/ IL-17 response in asthmatic mice. Secondly, the PM2.5 exposed asthmatic mice were orally administered with L9 (4×107, 4×109 CFU/mouse, day) from the day of first sensitization to the endpoint, for 20 days, to investigate the potential mitigative effect of L9 on asthma. The results showed that L9 ameliorated PM2.5 exposure enhanced AHR with an approximate 50% decrease in total airway resistance response to methacholine (48 mg/ml). L9 also prevented the exacerbated eosinophil and neutrophil infiltration in bronchoalveolar lavage fluid (BALF), and decreased the serum level of total IgE and OVA-specific IgG1 by 0.44-fold and 0.3-fold, respectively. Additionally, cytokine production showed that L9 significantly decreased T-helper cell type 2 (Th2)-related cytokines (IL-4, -5, -13) and elevated levels of Th1 related IFN-γ in BALF. L9 also reduced the level of IL-17A and increased the level of TGF-β. Taken together, these results indicate that L9 may exert the anti-allergic benefit, possibly through rebalancing Th1/Th2 immune response and modulating IL-17 pro-inflammatory immune response. Thus, L9 is a promising candidate for preventing PM exposure enhanced pre-existing asthma.
Shigella spp. and enteroinvasive Escherichia coli (EIEC) are widely distributed and can cause serious food-borne diseases for humans such as dysentery. Therefore, an efficient detection platform is ...needed to detect Shigella and EIEC quickly and sensitively. In this study, a method called recombinase polymerase amplification combined with lateral flow dipstick (RPA-LFD) was developed for rapid detection of Shigella and EIEC. RPA primers and LFD detection probes were designed for their shared virulence gene ipaH. Primers and probes were screened, and the primer concentration, and reaction time and temperature were optimized. According to the optimization results, the RPA reaction should be performed at 39°C, and when combined with LFD, it takes less than 25 min for detection with the naked eye. The developed RPA-LFD method specifically targets gene ipaH and has no cross-reactivity with other common food-borne pathogens. In addition, the minimum detection limit of RPA-LFD is 1.29×102 copies/μL. The detection of food sample showed that the RPA-LFD method was also verified for the detection of actual samples.
Ulcerative colitis (UC) is a relapsing and remitting inflammatory disease. Probiotics have a potential beneficial effect on the prevention of UC onset and relapse in clinical trials.
GG (
GG) have ...shown clinical benefits on UC patients, however, the precise mechanisms are unknown. The aim of this study is to explore the effect of extracellular vesicles released from
GG (LGG-EVs) on dextran sulfate sodium (DSS)-induced colitis and propose the underlying mechanism of LGG-EVs for protecting against colitis. The results showed that LGG-EVs could prevent colonic tissue damage and shortening of the colon (
< 0.01), and ameliorate intestinal inflammation by inhibiting TLR4-NF-κB-NLRP3 axis activation. Consistently, the pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-2) were suppressed effectively upon LGG-EVs treatment (
< 0.05). The 16S rRNA sequencing showed that LGG-EVs administration could reshape the gut microbiota in DSS-induced colitis mice, which further alters the metabolism pathways of gut microbiota. These findings propose a novel perspective of
GG in attenuating inflammation mediated by extracellular vesicles and offer consideration for developing oral gavage of LGG-EVs for colitis therapies.
The formation of viable but nonculturable (VBNC) Escherichia coli O157:H7 induced by high-pressure CO2 (HPCD) was investigated using RNA sequencing (RNA-Seq) transcriptomics and isobaric tag for ...relative and absolute quantitation (iTRAQ) proteomic methods. The analyses revealed that 97 genes and 56 proteins were significantly changed upon VBNC state entry. Genes and proteins related to membrane transport, central metabolisms, DNA replication, and cell division were mainly downregulated in the VBNC cells. This caused low metabolic activity concurrently with a division arrest in cells, which may be related to VBNC state formation. Cell division repression and outer membrane overexpression were confirmed to be involved in VBNC state formation by homologous expression of z2046 coding for transcriptional repressor and ompF encoding outer membrane protein F. Upon VBNC state entry, pyruvate catabolism in the cells shifted from the tricarboxylic acid (TCA) cycle toward the fermentative route; this led to a low level of ATP. Combating the low energy supply, ATP production in the VBNC cells was compensated by the degradation of l-serine and l-threonine, the increased AMP generation, and the enhanced electron transfer. Furthermore, tolerance of the cells with respect to HPCD-induced acid, oxidation, and high CO2 stresses was enhanced by promoting the production of ammonia and NADPH and by reducing CO2 production during VBNC state formation. Most genes and proteins related to pathogenicity were downregulated in the VBNC cells. This would decrease the cell pathogenicity, which was confirmed by adhesion assays. In conclusion, the decreased metabolic activity, repressed cell division, and enhanced survival ability in E. coli O157:H7 might cause HPCD-induced VBNC state formation.
Escherichia coli O157:H7 has been implicated in large foodborne outbreaks worldwide. It has been reported that the presence of as few as 10 cells in food could cause illness. However, the presence of only 0.73 to 1.5 culturable E. coli O157:H7 cells in salted salmon roe caused infection in Japan. Investigators found that E. coli O157:H7 in the viable but nonculturable (VBNC) state was the source of the outbreak. So far, formation mechanisms of VBNC state are not well known. In a previous study, we demonstrated that high-pressure CO2 (HPCD) could induce the transition of E. coli O157:H7 into the VBNC state. In this study, we used RNA-Seq transcriptomic analysis combined with the iTRAQ proteomic method to investigate the formation of VBNC E. coli O157:H7 induced by HPCD treatment. Finally, we proposed a putative formation mechanism of the VBNC cells induced by HPCD, which may provide a theoretical foundation for controlling the VBNC state entry induced by HPCD treatment.
•A new ZSD retrieval model used for complex coastal and inland waters was proposed.•The model raised the ZSD accuracy by altering absorption coefficient and water types.•The model can be applied to ...various sensors (MSI, MODIS, MERIS, OLCI and GOCI).
The estimation of water clarity in coastal and inland waters from satellite images is limited by significant uncertainties attributable to the optical complexity of these waters. To address this issue, we propose an improved semi-analytical model for retrieving the Secchi disk depth (ZSD) based on the mechanistic model (Lee model) developed by Lee et al. (2015). In the Lee model, a quasi-analytical algorithm (QAA) was employed to estimate the total absorption coefficient (a(λ)) and total backscattering coefficient (bb(λ)) to retrieve the diffuse attenuation coefficient (Kd(λ)). ZSD was then estimated by remote sensing reflectance (Rrs) and Kd. In this study, two improvements were made to the Lee model based on the band specifications of the Sentinel-2 Multispectral Instrument (MSI). First, the reference wavelength (λ0) was shifted from 560 nm and 665 nm to the longer red edge band 705 nm, and the modified empirical formula for estimating a(λ0) was applied to improve ZSD retrieval. Second, waters were classified into different optical water types (OWTs), and the optimal ZSD algorithm was identified for each OWT to further improve the accuracy of ZSD estimation. The proposed model (denoted as QAA_OWT) was calibrated and evaluated with in situ data (N = 399) collected from waters with various optical properties including a lake (Daihai Lake) dominated by colored dissolved organic matter (CDOM), a macrophytic lake (Ulansuhai Lake), and coastal water (the Bohai Sea) dominated by suspended sediments. The validation showed that QAA_OWT improved the accuracy of ZSD retrieval (0.18–5.0 m), with the averaged percentage difference (MAPD) decreasing from 31.9% to 24.9% and the root mean square deviation (RMSD) decreasing from 0.38 m to 0.32 m. The model was further applied to satellite images from the Sentinel-2 Multispectral Instrument (MSI) and independently assessed based on in situ-satellite match-ups (N = 31). The results verified the reliability of the model (MAPD = 31.8%, RMSD = 0.16 m). Time series MSI-derived ZSD maps clearly characterized the spatio-temporal patterns of the water clarity of Daihai Lake. Such maps are of significance in the accurate evaluation of the effectiveness of pollution control measures and aquatic ecosystem protection for lakes with low water quality. Sensitivity analysis revealed the robustness and insensitivity of the proposed model to input noise. This model could be applicable to many satellite sensors with spectral bands similar to those of Sentinel-2 MSI. Furthermore, it can be used as an effective tool for highly accurate remote sensing retrieval of ZSD in optically complex coastal and inland waters.
Pasteurization is carried out in dairy industries to kill harmful bacteria present in raw milk. However, endospore-forming bacteria, such as Bacillus, cannot be completely eliminated by ...pasteurization. In this study, a total of 114 Bacillus strains were isolated from 133 pasteurized milk samples. Antibiotic susceptibility tests showed that the percentage of Bacillus with intrinsic resistance to ampicillin and penicillin were 80 and 86%, respectively. Meanwhile, some Bacillus isolates had acquired resistance, including trimethoprim-sulfamethoxazole resistance (10 isolates), clindamycin resistance (8 isolates), erythromycin resistance (2 isolates), and tetracycline resistance (1 isolate). To further locate these acquired resistance genes, the plasmids were investigated in these 16 Bacillus strains. The plasmid profile indicated that Bacillus cereus BA008, BA117, and BA119 harbored plasmids, respectively. Subsequently, the Illumina Novaseq PE150 was applied for the genomic and plasmid DNA sequencing. Notably, the gene tetL encoding tetracycline efflux protein was found to be located on plasmid pBC46-TL of B. cereus BA117. In vitro conjugative transfer indicated that pBC46-TL can be transferred into Bacillus invictae BA142, Bacillus safensis BA143, and Bacillus licheniformis BA130. The frequencies were of 1.5 × 10−7 to 1.7 × 10−5 transconjugants per donor cells. Therefore, Bacillus strains with acquired antibiotic resistance may represent a potential risk for the spread of antibiotic resistance between Bacillus and other clinical pathogens via horizontal gene transfer.
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