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1.
Trials ; 21(1): 134, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32014046

RESUMO

BACKGROUND: Even though the effectiveness of lifestyle modifications and antihypertensive pharmaceutical treatment for the prevention of hypertension and its complications have been demonstrated in randomized controlled trials, the benefits of adhering to these treatments have not been popularized among the general public. Studies suggest that incentive approaches based on behavioral economic concepts can improve patients' adherence to treatment. Therefore, we aimed to test whether financial incentives will reduce the blood pressure (BP) of hypertensive patients in China. METHODS/DESIGN: This is a multicenter, randomized controlled trial with two parallel arms. A total of 400 participants from six cities in the Liaoning and Shanxi provinces of China are block-randomized into intervention and control group with a 1:1 ratio. Patients in the control group will receive interactive management of mobile devices, including patient education and communication. Patients in the intervention group will receive financial incentives in addition to interactive management of mobile devices, conditional on them achieving their antihypertensive goals or hypertension control. Masking the arm allocation will be precluded by the behavioral nature of the intervention and investigators of BP measurement and statistics are masked to clinic assignment. The primary outcome is net change in systolic BP (SBP) from baseline to month 12 between the intervention and control groups. The secondary outcomes are net change in diastolic BP (DBP), BP control, change in medication adherence and lifestyle, and cost-effectiveness. DISCUSSION: This trial will determine whether financial incentives will improve hypertension control and generate necessary data for controlling hypertension and concomitant cardiovascular diseases among hypertensive patients in China. TRIAL REGISTRATION: ISRCTN13467677. Registered on 16 May 2019.

2.
Curr Pharm Des ; 26(7): 780-789, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32031066

RESUMO

INTRODUCTION: The accumulation of amyloid-ß peptide (Aß) decreases cerebral blood flow in elderly people with Alzheimer's disease (AD) and is believed to be the initiator of this disorder. As a traditional Chinese medicine, Yangxue Qingnao (YXQN) improves cerebral insufficiency and attenuates cognitive impairment, showing potential against AD. But whether YXQN has the ability to block Aß self-aggregation is rarely reported. OBJECTIVE: Here, we investigate the effects of YXQN on Aß accumulation and its mediated cytotoxicity using a range of biochemical, biophysical, and cell-based approaches. METHODS: Thioflavin T assay, transmission electron microscope, and 1H NMR experiments were used to investigate the effects of YXQN on Aß fibrogenesis and aggregation. Far-UV CD spectra were acquired to assess the alteration of YXQN on the conformation of the amyloid protein. Three short Aß42 peptides (AA 1-16, AA 17-33 and AA 28-42) were designed to analyse the Aß42 epitope to which YXQN components bind. The effect of YXQN on Aß-induced cytotoxicity was investigated through SH-SY5Y cell viability assay. RESULTS: We provide evidence showing that YXQN clearly reduces Aß42 fibrillogenesis and alters its ß-sheet conformation, indicating the inhibition of primary nucleation of amyloid protein. Using the different Aß short peptides, residues 17-33 were identified as the target epitope for YXNQ components interacting with Aß42. Furthermore, in the SH-SY5Y cell injury model, our data show that high-dose YXQN attenuates amyloid-induced cytotoxicity approximately 60% and effectively ameliorates cell distortion in morphology. CONCLUSION: Based on these results, YXQN exerts a neuroprotective effect by inhibiting Aß42 toxic aggregation, which has the potential to combat AD.

3.
Sci Total Environ ; 714: 136799, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-31982768

RESUMO

The application of anammox process in mainstream wastewater treatment process is still facing challenges especially at the low temperature. To resolve this problem, the coexistence system of anaerobic ammonia-oxidizing bacteria (AnAOB) and heterotrophic bacteria (HB) was built in this study. The nitrogen removal efficiency mainly maintained at above 90% during the process of temperature reducing from 35 °C to 10 °C. The nitrogen removal rate were 0.30 g N·L-1·d-1 at both 25 and 15 °C and 0.10 g N·L-1·d-1 at 10 °C, respectively. Analysis of 16S rRNA genus sequencing revealed that as the temperature reduced to 10 °C, the Denutrotisoma genera presented a downward trend but Comamonadaceae genera showed an upward trend. At 10 °C, the contrast of anammox activities between granular and flocculent sludge in the system revealed that although the abundance of anammox genera was much lower in flocculent sludge than that in granular sludge, the anammox activities showed no significant discrepancy. And the abundance of Comamonadaceae and Chloroflexales genera were much higher in flocculent sludge than those in granular sludge, presenting their key roles to anammox activity at low temperature. The Circos diagram and Cluster of orthologous Group of protein functional predication showed that the functional abundance related to interaction among microbial communities were higher in flocculent sludge but those related to self-growth was higher in granular sludge. This result indicated the significance of the interactions based on the microbial diversity in the application of annamox process at low temperature.


Assuntos
Reatores Biológicos , Microbiota , Águas Residuárias , Anaerobiose , Bactérias , Nitrogênio , Oxirredução , RNA Ribossômico 16S , Esgotos , Temperatura Ambiente
5.
Arch Physiol Biochem ; 126(1): 41-48, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30317878

RESUMO

This study was to examine the role of exercise intervention in modulating neuropathic pain induced by diabetes. Diabetes was induced by streptozotocin (STZ, i.p.) in rats and mechanical hyperalgesia was observed three weeks after STZ. Mechanical withdrawal thresholds were increased after four to five weeks of exercise in STZ rats. We also examined the role of signal of mammalian target of rapamycin (mTOR) in regulating neuropathic pain. Inhibition of neuropathic pain by exercise in STZ rats was accompanied with decreases of p-mTOR, p-S6K1, and p-4E-BP1 in sensory nerves. Blocking mTOR also elevated mechanical withdrawal thresholds in STZ rats. Furthermore, pro-inflammatory IL-6 was greater in sensory nerves of STZ rats. Inhibition of IL-6 decreased mTOR and increased mechanical withdrawal thresholds in STZ rats. Overall, our data suggest the role played by exercise in improving neuropathic pain after STZ and that IL-6-mTOR signal is a part of mechanisms engaged in the effects of exercise.

6.
ISME J ; 14(1): 151-163, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31595050

RESUMO

Global-scale N-oxide contamination of groundwater within aquifers occurs due to the widespread use of N-bearing fertilizers and chemicals, threatening both human and environmental health. However, the conversion of these pollutants in active nitrogen (N) cycling processes in the subsurface biosphere still remains unclear. This study investigates the global occurrence of anaerobic ammonium oxidation (anammox) in aquifers, where anammox was found to be turned on and off between saturated and unsaturated soil horizons, and contributed 36.8-79.5% to N loss in saturated soil horizons, the remainder being due to denitrification which has traditionally been considered the main pathway for removal of N-pollutants from aquifers. Although anammox activity was undetectable in the unsaturated soil horizons, it could potentially be activated by contact with ascending groundwater. High-throughput pyrosequencing analysis identified Candidatus Brocadia anammoxidans as being the most abundant anammox bacterium in the saturated soils investigated. However, the anammox bacterial abundance was determined by the relative richness of Candidatus Jettenia asiatica. Isotopic pairing experiments revealed that coupling anammox with ammonium oxidation and respiratory ammonification enabled the formation of a revised N cycle in aquifer systems, in which respiratory ammonification acted as an important coordinator. Anammox can therefore contribute substantially to aquifer N cycling and its role in remediation of aquifers contaminated with N-oxides may be of global importance.


Assuntos
Compostos de Amônio/metabolismo , Água Subterrânea/química , Ciclo do Nitrogênio , Óxidos de Nitrogênio/metabolismo , Poluentes Químicos da Água/metabolismo , Anaerobiose , Bactérias/isolamento & purificação , Bactérias/metabolismo , Desnitrificação , Água Subterrânea/microbiologia , Nitrogênio/metabolismo , Oxirredução , Solo/química , Microbiologia do Solo
7.
Int J Pharm ; 572: 118796, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31678389

RESUMO

We report preparation of theranostic nanocarriers loaded with up to 50 wt% of the anticancer drug doxorubicin that contain magnetic nanoparticles which enable Magnetic Particle Imaging (MPI), an emerging technology for quantitative and unambiguous imaging of the nanocarriers. The nanocarriers, coated with poly(ethylene glycol)-block-poly(lactic acid) (PEG4.9kD-b-PLA6kD) block copolymer for colloidal stability, are composed of a hydrophobic core of precipitated hydrolysable doxorubicin prodrug (proDox) and magnetic nanoparticles. Transmission electron microscopy (TEM) shows evidence of precipitated proDox for nanocarriers with high drug loading of up to 50 wt%. MPI measurements show that the nanocarriers can be quantitatively imaged. The nanocarriers are internalized by MDA-MB-231 cells and their IC50 value via metabolic assay is 1.1 µM, compared to 0.21 µM for free doxorubicin. The release rate from the nanocarriers was dependent on environmental pH. These nanocarriers with high drug loading and quantitative imaging are promising candidates for future applications.

8.
J Med Chem ; 62(24): 11324-11334, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31765154

RESUMO

Diverse platinum drug candidates have been designed to improve inhibitory potency and overcome resistance for orthotopic tumors. However, the antimetastatic properties have rarely been reported. We herein report that homospermidineplatin (4a), a polyamine-Pt(IV) prodrug, can potently inhibit tumor growth in situ and reverse cisplatin resistance as expected, and more importantly, 4a displays remarkably elevated antimetastatic activity in vivo (65.7%), compared to those of cisplatin (27.0%) and oxaliplatin (19.6%). The underlying molecular mechanism indicates that in addition to targeting nuclear DNA, 4a can modulate polyamine metabolism and function in a manner different from that of cisplatin. By upregulating SSAT and PAO, 4a downregulates the concentrations of Put, Spd, and Spm, which favors the suppression of fast-growing tumor cells. Moreover, the p53/SSAT/ß-catenin and PAO/ROS/GSH/GSH-Px pathways are involved in the inhibition of 4a-induced tumor metastasis. Our study implies a promising strategy for the design of platinum drugs for the treatment of terminal cancer.

9.
Cell Commun Signal ; 17(1): 153, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31752909

RESUMO

BACKGROUND: Abnormal reactivation of androgen receptor (AR) signaling in castration-resistant prostate cancer (CRPC) mainly results from overexpression and down-regulation of AR. Sumoylation of AR can influence its function. However, regulation of AR sumoylation by SUMO E3 ligases PIASs to modify AR distribution and stability are not well understood. METHODS: We assessed the potential effect of SUMO3 modification on AR intracellular localization by immunostaining in AR-negative prostate cancer DU145 cells, and detected the effect of PIAS1/SUMO3 overexpression on AR sumoylation related degradation. Then we characterized AR sumoylation sites involved modified by SUMO3, and the key residue of PIAS1 involved in itself sumoylation and further mediated AR sumoylation (sumo3-conjugated), translocation and degradation. Finally we detected the recognition of PIAS1 (sumoylation ligase) to MDM2, a ubiquin ligase mediated AR degradation. RESULTS: We demonstrate that SUMO E3 ligase PIAS1, along with SUMO3, mediates AR cytosolic translocation and subsequent degradation via a ubiquitin-proteasome pathway. Although AR sumoylation occurs prior to ubiquitination, the SUMO-acceptor lysine 386 on AR, together with ubiquitin-acceptor lysine 845, contribute to PIAS1/SUMO3-induced AR nuclear export, ubiquitination and subsequent degradation. Moreover, PIAS1 itself is modified by SUMO3 overexpression, and mutation of SUMO-acceptor lysine 117 on PIAS1 can impair AR cytoplasmic distribution, demonstrating the essential role of sumoylated PIAS1 in AR translocation. We further determine that sumoylated PIAS1 interacts with AR lysine 386 and 845 to form a binary complex. Consistent with the effect on AR distribution, SUMO3 modification of PIAS1 is also required for AR ubiquitination and degradation by recruiting ubiquitin E3 ligase MDM2. CONCLUSION: Taken together, SUMO3 modification of PIAS1 modulates AR cellular distribution and stability. Our study provided the evidence the crosstalk between AR sumoylation and ubquitination mediated by PIAS1 and SUMO3.

10.
J Food Sci Technol ; 56(10): 4632-4647, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31686695

RESUMO

This study investigated the effect of brewing apparatus on the aromatic feature of tea infusion. Huangshan Maofeng tea infusion was brewed under glass tumblers (GT) or thermos vacuum mugs (TVM) for up to 180 min. Tea infusion sensory attributes were evaluated using quantitative descriptive analysis and the composition of volatiles were analyzed using headspace solid phase microextraction coupled with gas chromatography-mass spectrometry. Results showed that GT tea infusion at each brewing duration possessed stronger 'Pure', 'Fresh' and 'Grassy' attributes than TVM tea infusion, whereas TVM tea infusion showed a higher intensity on 'Steamed' aroma. A total of 74 volatiles were detected in tea infusion, and aldehydes and alcohols appeared to be the major volatiles. Total aldehydes concentration percentage decreased in tea infusion with brewing process, whereas an increase on total alcohol percentage was found. Principal component analysis indicated that brewing duration and apparatus played vital roles in altering the volatile composition in tea infusion, whereas orthogonal partial least squares discriminant analysis (OPLS-DA) revealed that GT tea infusion samples were separated from TVM tea infusion samples. OPLS-DA also screened 20 volatiles that significantly contributed to the differentiation of GT and TVM tea infusion.

11.
Int J Biol Sci ; 15(10): 2256-2264, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31592132

RESUMO

Nature has generously offered life-saving therapies to mankind by providing evolutionarily optimized drug-like entities in the form of natural products. These splendid gifts of nature have served as most suitable candidates for anti-cancer drug discovery due to their pleiotropic activity on target molecules. This review aims to provide an update on the natural sources and bioactivities of such gifts from nature, salvianolic acid A & B, which are major bioactive constituents of a traditional Chinses medicinal herb, Salvia miltiorrhiza. Salvianolic acid A & B have been reported to owe anti-cancer, anti-inflammatory and cardioprotective activities. Currently salvianolic acids have been emerged as potent anti-cancer molecules. Salvianolic acid A & B fight cancer progression by prompting apoptosis, halting cell cycle and adjourning metastasis by targeting multiple deregulated signaling networks of cancer. Moreover, salvianolic acid A & B display potency towards sensitizing cancer cells to chemo-drugs. The review purposes that salvianolic acid A & B supply a novel opportunity for drug discovery but further experimentation is mandatory to embellish the knowledge of their pharmacological usage and to access their toxicological limits in order to establish these compounds as potential multitarget future drugs.

12.
PLoS One ; 14(10): e0223599, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31647842

RESUMO

OBJECTIVE: To comprehensively determine the prevalence of MRSA in healthy Chinese population, the influencing factors of MRSA colonization and its antibiotic resistance. METHODS: Articles that studied prevalence or influencing factors of MRSA carriage in healthy Chinese population were retrieved from PubMed, Ovid database, three Chinese electronic databases. The pooled prevalence of MRSA, its antibiotic resistance and influencing factors were analyzed by STATA12.0. RESULTS: 37 studies were included. The pooled prevalence of MRSA was 21.2% (95% CI: 18.5%-23.9%), and the prevalence of S.aureus was 15% (95% CI: 10%-19%), with a significant heterogeneity (MRSA: I2 = 97.6%, P<0.001; S.aureus: I2 = 98.4%, P < 0.001). In subgroup analysis, the pooled prevalence of MRSA was 28% (95%CI: 10%-51%) for Livestock-related workers, 18% (95%CI: 11%-26%) for children, 20% (95%CI: 12%-29%) for healthcare workers, 7% (95%CI: 3%-13%) for community residents. The prevalence of MRSA in studies with oxacillin disk diffusion method (28%, 95%CI: 21%-35%) seemed higher than that with the mecA gene method(12%, 95%CI: 7%-19%). MRSA in studies conducted in Taiwan was more common than in Mainland China and Hong Kong. Similar results were found in meta-regression. Influencing factors for MRSA colonization were noted in seven eligible studies, they included younger age (OR: 3.54, 95% CI: 2.38-5.26; OR: 2.24, 95% CI: 1.73-2.9), attending day care centers (DCCs) (OR: 1.95, 95% CI: 1.4-2.72; OR: 1.53, 95% CI: 1.2-1.95), flu vaccination (OR:1.73, 95% CI: 1.28-2.35), using antibiotics within the past year (OR: 2.05, 95% CI:1.35-3.11), residing in northern Taiwan (OR: 1.45, 95% CI: 1.19-1.77), regular visits to health care facility (OR: 23.83, 95% CI: 2.72-209.01), household member working in health care facility (OR: 8.98, 95% CI:1.4-55.63), and contact with livestock (OR: 6.31, 95% CI: 3.44-11.57). Moreover, MRSA was found to be highly resistant to penicillin, ampicillin, erythromycin, and clindamycin, with a pooled resistance ratio of 100, 93, 88, and 75%, respectively. However, no resistance were noted to vancomycin. CONCLUSION: The pooled prevalence of MRSA was considerably high in health Chinese population. Additionally, these strains showed extreme resistance to penicillin, ampicillin, erythromycin and clindamycin. Public MRSA protection measures and the surveillance of MRSA should be strengthened to reduce the spread of MRSA among hospitals, communities, and livestock.

13.
J Hum Hypertens ; 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477823

RESUMO

This study was performed to investigate the association between stage 1 hypertension defined by the 2017 ACC/AHA guidelines and the risk of adverse events among adults aged 35 to 49 years. A total of 20,072 adults aged 35-49 years, without a history of cardiovascular disease (CVD) at baseline were included in the present study. Adjusted Cox proportional hazards models were applied to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). During a median follow-up period of 12.5 years, the results indicated that 777 subjects suffered all-cause death and 299 subjects developed CVD. A total of 830 subjects were involved in incident stroke and 141 subjects had a myocardial infarction (MI). Stage 1 hypertension had a HR (95% CI) of 1.38 (1.13-1.70) for all-cause mortality, 1.74 (1.20-2.53) for CVD mortality, 1.78 for (1.40-2.26) for stroke incidence, and 1.64 (0.99-2.71) for MI incidence, respectively, compared with blood pressure (BP) <120/<80 mmHg. The results show that after adjusting for sex, age, and other potential CVD factors, the incidence of stroke was the only parameter significantly associated with stage 1 hypertension (HR and 95% CI: 1.53, 1.20-1.95). Stage 1 hypertension defined by the 2017 ACC/AHA guidelines was associated with an increased risk of stroke among adults aged 35 to 49 years in rural areas of China.

14.
J Food Sci Technol ; 56(9): 4333-4348, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31478003

RESUMO

This study aimed to evaluate the effect of storage temperature on the alteration of the sensory quality of tea. Huangshan Maofeng tea was stored at - 80 °C, - 20 °C, 4 °C, or room temperature for up to 150 days. The physicochemical parameters, taste-related components, appearance color, volatile compounds and sensory quality of tea were analyzed and compared. Results showed that storing tea at - 80 °C and - 20 °C effectively preserved the physicochemical parameters, taste-related compounds and appearance color in tea. Multivariate statistical analysis (PCA and OPLS-DA) indicated that tea stored at - 80 °C exhibited a similar volatiles composition as fresh tea based on gas chromatography-mass spectrometry, whereas the composition of volatiles was significantly altered in tea stored at 4 °C after 100 days of storage. Sensory evaluation illustrated that tea stored at - 80 °C and - 20 °C remained the freshness regarding leaves appearance and tea infusion color, taste and aroma, whereas an obvious decrease on the tea freshness was found in tea stored at 4 °C and room temperature. These findings indicated that storage temperature played a vital role in altering the aromatic and sensory quality of Huangshan Maofeng tea and the recommended tea storage temperature was - 80 °C or - 20 °C.

15.
Appl Microbiol Biotechnol ; 103(19): 8191-8202, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31478060

RESUMO

Although the niche differentiation of anammox bacteria has been extensively observed in a lab-scale reactor, the inherent mechanism for this ecological phenomenon is still elusive. Here, we combined the long-term reactor operation, genome-centered metagenome, and metatranscriptome analyses to gain insight into the substrate competition and niche differentiation of Candidatus Jettenia and Candidatus Brocadia. After 146 days of operation, we found the anammox bacterial population shifted from Ca. Jettenia to Ca. Brocadia in the immobilization-anaerobic baffled reactor (I-ABR) with the ammonium and nitrite concentrations of 30 mg/L. Importantly, the genome and transcript comparisons of Ca. Jettenia and Ca. Brocadia showed that Ca. Brocadia harbored more complete function in cell chemotaxis, flagellar assembly, and two-component system and more redundant function in nitrite reduction, in which the genes were also highly expressed. Ca. Brocadia out-competed Ca. Jettenia at the mainstream condition. Meanwhile, though the highest biomass concentration led to the highest nitrogen removal rate (NRR) in the first compartment (C1), the competition of Ca. Jettenia and Ca. Brocadia could also affect the NRR of different compartments through affecting the bacterial activity. Substrate competition of anammox bacteria led to higher transcript activity of Ca. Jettenia and Ca. Brocadia in the second (C2) and fourth (C4) compartments, respectively. Further, high transcript activity of Ca. Brocadia led to the higher NRR in C4. A comparison of metabolic potential based on the metagenome-assembled genome adds a different dimension for understanding the discrepantly physiological characteristics and competition of anammox bacteria for wastewater treatment.


Assuntos
Amônia/metabolismo , Antibiose , Bactérias/classificação , Bactérias/metabolismo , Metagenômica/métodos , Anaerobiose , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Perfilação da Expressão Gênica/métodos , Oxirredução
16.
Zool Res ; 40(5): 343-348, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31393095

RESUMO

Research on in vitro culture and gene editing of domestic spermatogonial stem cells (SSCs) is of considerable interest but remains a challenging issue in animal science. In recent years, some progress on the isolation, purification, and genetic manipulation of porcine SSCs has been reported. Here, we summarize the characteristics of porcine SSCs as well current advances in their in vitro culture, potential usage, and genetic manipulation. Furthermore, we discuss the current application of gene editing in pig cloning technology. Collectively, this commentary aims to summarize the progress made and obstacles encountered in porcine SSC research to better serve animal husbandry, improve livestock fecundity, and enhance potential clinical use.


Assuntos
Células-Tronco Germinativas Adultas , Edição de Genes , Espermatogônias , Suínos/genética , Animais , Masculino
18.
Water Res ; 165: 114974, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31450220

RESUMO

Although the enhancement of anammox performance for wastewater treatment due to the addition of small amount of acetate has been reported, discrepant metabolic responses of different anammox species have not been experimentally evaluated. Based on metagenomics and metatranscriptomic data, we investigated the competitiveness between two typical anammox species, Candidatus Jettenia caeni (J. caeni) and Candidatus Brocadia sinica (B. sinica), in anammox consortia under mixotrophic condition, where complex metabolic interactions among anammox bacteria and heterotrophs also changed with acetate addition. Contrary to J. caeni, the dissimilatory nitrate reduction to ammonium pathway of B. sinica was markedly stimulated for improving nitrogen removal. More acetate metabolic pathways and up-regulated AMP-acs expression for acetyl-CoA synthesis in B. sinica contributed to its superiority in acetate utilization. Interestingly, cross-feedings, including the nitrogen cycle, amino acid cross-feeding and B-vitamin metabolic exchange between B. sinica and other heterotrophs seemed to be enhanced with acetate addition, contributing to a reduction in metabolic energy cost to the whole community. Our work not only clarified the mechanism underlying discrepant responses of different anammox species to acetate, but also suggests a possible strategy for obtaining higher nitrogen removal rates in wastewater treatment under low C/N ratio.


Assuntos
Compostos de Amônio , Bactérias , Acetatos , Anaerobiose , Reatores Biológicos , Nitrogênio , Oxirredução , Águas Residuárias
19.
Water Res ; 162: 269-275, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31280085

RESUMO

Anaerobic methane generation from algae is hindered by the slow and poor algae biodegradability. A novel free ammonia (NH3 i.e. FA) pretreatment technology was proposed in this work to enhance anaerobic methane generation from algae cultivated using a real secondary effluent. The algae solubilisation was 0.05-0.06 g SCOD/g TCOD (SCOD: soluble chemical oxygen demand; TCOD: total chemical oxygen demand) following FA pretreatment of 240-530 mg NH3-N/L for 24 h, whereas the solubilisation was only 0.01 g SCOD/g TCOD for the untreated algae. This indicates that FA pretreatment at 240-530 mg NH3-N/L could substantially enhance algae solubilisation. Biochemical methane potential tests revealed that FA pretreatment on algae at 240-530 mg NH3-N/L is able to significantly enhance anaerobic methane generation. The hydrolysis rate (k) and biochemical methane potential (P0) of algae increased from 0.21 d-1 and 132 L CH4/kg TCOD to 0.33-0.50 d-1 and 140-154 L CH4/kg TCOD, respectively, after the algae was pretreated by FA at 240-530 mg NH3-N/L. Further analysis indicated that FA pretreatment improved k of both quickly and slowly biodegradable substrates, and also increased P0 of the slowly biodegradable substrate although it negatively affected P0 of the quickly biodegradable substrate. This FA technology is a closed-loop technology.


Assuntos
Amônia , Metano , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Esgotos
20.
Water Res ; 163: 114872, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31362210

RESUMO

One stage partial nitritation-anammox (PN-A) process has attracted more and more attention due to the low investment cost but the instability in treating low strength wastewater. In this study, for producing a novel composite carrier that could provide high ammonia microenvironment in low strength wastewater, the zeolites and floating materials were combined in the spherical shell and distributed evenly by the spherical polyhedron. And a moving bed biofilm reactor (MBBR) with the composite carriers and ordinary carriers without zeolites as control group was operated for nearly 120 days. The PN-A process were realized in 53 days, and the total nitrogen removal efficiency reached around 85% at influent ammonium concentration of 50 mg/L finally. Analysis of 16S rRNA gene sequencing revealed that the composite carriers showed significant promotion on the proliferation of ammonium oxidizing bacteria (AOB) and enrichment of anaerobic ammonium oxidizing bacteria (AnAOB), accounting for 19.14% and 41.65% on the surface, respectively. Moreover, the existence of relative higher abundance of ammonia on the composite carrier surface was validated by the metabolite biomarker of glutamate and especially spermidine. The metabolomics analysis and 16S rRNA function prediction showed that the protein synthesis pathway was obviously upregulated on the composite carriers surface compared with that on the ordinary carriers surface. The higher abundance of glutamate and putrescine indicated that the composite carrier could stimulate the metabolism and growth of bacteria. The present study provided a functional carrier to realize the transformation of activated sludge system into PN-A system treating low strength wastewater, which is significant to the application of the process in mainstream.


Assuntos
Compostos de Amônio , Águas Residuárias , Biofilmes , Reatores Biológicos , Nitrogênio , Oxirredução , RNA Ribossômico 16S , Esgotos
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