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1.
Parasit Vectors ; 14(1): 186, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33794979

RESUMO

BACKGROUND: Microsporidia are obligate intracellular parasites that can infect nearly all invertebrates and vertebrates, posing a threat to public health and causing large economic losses to animal industries such as those of honeybees, silkworms and shrimp. However, the global epidemiology of these pathogens is far from illuminated. METHODS: Publications on microsporidian infections were obtained from PubMed, Science Direct and Web of Science and filtered according to the Newcastle-Ottawa Quality Assessment Scale. Infection data about pathogens, hosts, geography and sampling dates were manually retrieved from the publications and screened for high quality. Prevalence rates and risk factors for different pathogens and hosts were analyzed by conducting a meta-analysis. The geographic distribution and seasonal prevalence of microsporidian infections were drawn and summarized according to sampling locations and date, respectively. RESULTS: Altogether, 287 out of 4129 publications up to 31 January 2020 were obtained and met the requirements, from which 385 epidemiological data records were retrieved and effective. The overall prevalence rates in humans, pigs, dogs, cats, cattle, sheep, nonhuman primates and fowl were 10.2% [2429/30,354; 95% confidence interval (CI) 9.2-11.2%], 39.3% (2709/5105; 95% CI 28.5-50.1%), 8.8% (228/2890; 95% CI 5.1-10.1%), 8.1% (112/1226; 95% CI 5.5-10.8%), 16.6% (2216/12,175; 95% CI 13.5-19.8%), 24.9% (1142/5967; 95% CI 18.6-31.1%), 18.5% (1388/7009; 95% CI 13.1-23.8%) and 7.8% (725/9243; 95% CI 6.4-9.2%), respectively. The higher prevalence in pigs suggests that routine detection of microsporidia in animals should be given more attention, considering their potential roles in zoonotic disease. The highest rate was detected in water, 58.5% (869/1351; 95% CI 41.6-75.5%), indicating that water is an important source of infections. Univariate regression analysis showed that CD4+ T cell counts and the living environment are significant risk factors for humans and nonhuman primates, respectively. Geographically, microsporidia have been widely found in 92 countries, among which Northern Europe and South Africa have the highest prevalence. In terms of seasonality, the most prevalent taxa, Enterocytozoon bieneusi and Encephalitozoon, display different prevalence trends, but no significant difference between seasons was observed. In addition to having a high prevalence, microsporidia are extremely divergent because 728 genotypes have been identified in 7 species. Although less investigated, microsporidia coinfections are more common with human immunodeficiency virus and Cryptosporidium than with other pathogens. CONCLUSIONS: This study provides the largest-scale meta-analysis to date on microsporidia prevalence in mammals, birds and water worldwide. The results suggest that microsporidia are highly divergent, widespread and prevalent in some animals and water and should be further investigated to better understand their epidemic features.

3.
BMC Health Serv Res ; 21(1): 267, 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33757490

RESUMO

BACKGROUND: To implement the "without the need for a second visit" (WNASV) initiative in our hospital by optimizing the outpatient clinic services via an upgraded information system, in order to increase the quality of outpatient medical services and improve patients' satisfaction. METHODS: An Internet-based care delivery approach was developed and applied to improve the delivery of health care services, simplify the treatment process, and reduce patient waiting time. The patient waiting time and consultation time in the outpatient clinics of our hospital during the peak service intervals and the proportions of various payment methods for outpatient services during the period from May 2017 to September 2019 were retrospectively analyzed. Also, the patients' satisfaction with the outpatient process was surveyed. RESULTS: The waiting time for consultation was shortened from 32.25 min to 28.42 min; the consultation time was shortened from 6.52 min to 3.15 min; and the waiting time for payment decreased from 7.40 min to 4.31 min. The proportion of payment via a counter was reduced from 86.80 to 21.79%, the proportion of self-service payment increased from 9.99 to 16.05%, and the proportion of payment during a consultation increased from 3.21 to 61.91%. The scores of the patients' satisfaction with the outpatient services increased from an average of 89.10 points in 2017 to an average of 90.26 points in 2019. CONCLUSION: The continuous improvement of the service process markedly increases the efficiency of the outpatient services, and effectively improves patient's satisfaction with the outpatient process, this initiative thus deserves further application.

4.
ACS Appl Mater Interfaces ; 13(12): 14752-14758, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33729763

RESUMO

Constructing composite electrodes is considered to be a feasible way to realize high-specific-capacity Li-ion batteries. The core-double-shell-structured Si@C@TiO2 would be an ideal design for such batteries, considering that carbon (C) can buffer the volume change and TiO2 can constrain the structural deformation of Si. Although the electrochemical performance of the shells themselves is relatively clear, the complexity of the multishell heterointerface always results in an ambiguous understanding about the influence of the heterointerface on the electrochemical properties of the core material. In this work, a multilayer film model that can simplify and simultaneously expand the area of the heterointerface is used to study the heterointerfacial behavior. First, a multilayer film TiO2/C with different numbers of TiO2/C heterointerfaces is studied. It shows that the electrochemical performance is enhanced apparently by increasing the number of TiO2/C heterointerfaces. On the one hand, the TiO2/C heterointerface exhibits a strong lithium-ion storage capacity. On the other hand, the TiO2/C heterointerface appears to effectively promote the local Li-ion concentration gradient and thus boost the Li-ion transport kinetics. Then, TiO2/C is combined with Si to construct a composite anode Si/C/TiO2. An obvious advantage of TiO2/C over single TiO2 and C is observed. The utilization rate of Si is greatly improved in the first cycle and reaches up to 98% in Si/C/TiO2. The results suggest that the electrochemical performance of Si can be greatly manipulated by the heterointerface between the multishells.

5.
J Sci Food Agric ; 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33740265

RESUMO

BACKGROUND: Esters are indispensable aroma compounds and contribute significantly to fruity-aroma in fermented condiments. The ester-synthesis activity and pathway of Bacillus licheniformis, Candida etchellsii and Zygosaccharomyces rouxii isolated from Chinese horse bean-chili-paste were investigated. Chemical buffer models containing esterification and alcoholysis systems inoculated with extracellular extracts of these three strains were established. RESULTS: The ester-synthesis activity of C. etchellsii was stronger than the other two strains. Z. rouxii could synthesize acetate esters via esterification, while the biosynthesis pathways of B. licheniformis and C. etchellsii were esterification and alcoholysis. Esterification exhibited relatively high activity at pH 4, while the alcoholysis activity improved with the increase of pH from 4 to 8. Moreover, C. etchellsii could synthesize C6 -C8 of acetate esters, and its activity improved with the number of alcohol carbon atoms. These three strains could synthesize C10 -C18 of ethyl esters. Their synthesis activity of ethyl esters decreased with aliphatic acid carbon number. CONCLUSION: Candida etchellsii is potential to be used in CHCP fermentation in order to the accumulation of esters and the improvement of flavor compared with the other two strains. This research is conducive to understanding the mechanism of ester-synthesis in fermented condiments. This article is protected by copyright. All rights reserved.

6.
PLoS One ; 16(3): e0248173, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33784345

RESUMO

In this paper, we investigate the outage probability and ergodic sum capacity of the downlink of the integrated satellite-terrestrial networks (ISTN) with a cooperative non-orthogonal multiple access (CNOMA) scheme, in which a user with better channel condition acts as a relay node and forwards information to the other users. In this paper, a pilot-based channel estimation method is considered which can verify the performance of this scheme with the imperfect channel state information. In this model, all these users are equipped with multi-antennas, and all of them are both in the coverage of a same beam of the satellite. Specifically, the exact analytical expression for the outage probability and ergodic sum capacity of the system is derived. The result shows that this coordinated non-orthogonal multiple access (CNOMA) scheme performs better than that of OMA (TDMA) in this model. Finally, the future research directions are given to further enhance the system capacity.

8.
Water Res ; 194: 116958, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33662685

RESUMO

Methane (CH4) and nitrous oxide (N2O) are the most powerful greenhouse gases globally; recent emissions exceed previous estimates. The potential link between N2O reduction and CH4 oxidation in anoxic wetland sediments would be a sink for both gases, which has attracted broad attention. To explore the simultaneous N2O and CH4 biotransformation, wetland sediments were used to inoculate an enrichment reactor, continuously fed with CH4 and N2O for 500 days. After enrichment, the CH4 oxidation rate reached 2.8 µmol·g-1dw·d-1, which was 800-fold higher than the rate of the wetland sediments used as inoculum. Moreover, stable isotopic tracing proved CH4 oxidation was driven by N2O consumption under anoxic conditions. Genomic sequencing showed that the microbial community was dominated by methanotrophs. Species of Methylocaldum genus, belonging to γ-Proteobacteria class, were significantly enriched, and became the predominant methanotrophs. Quantitative analysis indicated methane monooxygenase and nitrous oxide reductase increased by 38- and 8-fold compared to the inoculum. As to the potential mechanisms, we propose that N2O-driven CH4 oxidation was mediated by aerobic methanotrophs solely or along with denitrifying bacteria under hypoxia. Electrons and energy are generated and transferred in the oxidative phosphorylation pathway. Our findings expand the range of electron acceptors associated with CH4 oxidation as well as elucidate the significant role of methanotrophs relative to both carbon and nitrogen cycles.


Assuntos
Gases de Efeito Estufa , Óxido Nitroso , Humanos , Hipóxia , Metano/análise , Óxido Nitroso/análise , Áreas Alagadas
9.
J Chromatogr Sci ; 2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33728454

RESUMO

Capilliposide B (CPS-B) and Capilliposide C (CPS-C), as the key components in Lysimachia capillipes Hemsl., increasingly aroused the interest and research concern of many researchers due to the good bioactivities. Nowadays, the reference standards of CPS-B and CPS-C yield were very limited. Due to the deficit of reference standards, the determination could be difficult to carry out, and the quality control and evaluation would be restrained afterwards. To solve this urgent problem, a quantitative analysis of multi-components by single-marker (QAMS) method was proposed and established based on high-performance liquid-chromatography tandem evaporative light-scattering detector. In this QAMS method, the content of the two bioactive components could be calculated by buddlejasaponin IV, which is applied as an external standard and readily obtained. And the methodological experiments were evaluated and indicated accuracy, stability and feasibility of this QAMS method. Therefore, in this study, this built method would properly meet the requirement of determination of CPS-B, CPS-C and quality control of the L. capillipes Hemsl. plant.

10.
Medicine (Baltimore) ; 100(8): e24882, 2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33663116

RESUMO

INTRODUCTION: Our aim was to evaluate the safety and efficacy of low-dose mineralocorticoid receptor antagonists (MRAs) in dialysis patients. METHODS: We systematically searched PubMed, EMBASE, and Cochrane libraries for clinical trials on the use of MRAs in dialysis patients. Review Manager 5.3 software was used to analyze relevant data and evaluate the quality of evidence. RESULTS: We identified nine randomized controlled trials including 1128 chronic dialysis patients. In terms of safety, when hyperkalemia was defined as serum potassium level ≥5.5 mmol/L, low-dose MRAs were significantly associated with hyperkalemia (relative risk [RR] 1.76, 95% confidence intervals [CI] 1.07-2.89, P = .02); however, when hyperkalemia was defined as serum potassium level ≥6.0 mmol/L or serum potassium level ≥6.5 mmol/L, no significant association was observed between low-dose MRAs and hyperkalemia (RR 1.40, 95% CI 0.83-2.37, P = .20; RR 1.98, 95% CI 0.91-4.30, P = .09, respectively). Use of low-dose MRAs can reduce cardiovascular mortality by 54% compared with the control group (0.46, 95% CI 0.28-0.76, P = .003). Similarly, the RR of all-cause mortality for the low-dose MRAs group was 0.48 (95% CI 0.33-0.72, P = .0003). CONCLUSION: Low-dose MRAs may benefit dialysis patients without significantly increasing moderate to severe hyperkalemia.


Assuntos
Antagonistas de Receptores de Mineralocorticoides/administração & dosagem , Diálise Renal/métodos , Doenças Cardiovasculares/mortalidade , Doenças Cardiovasculares/prevenção & controle , Humanos , Hiperpotassemia/induzido quimicamente , Antagonistas de Receptores de Mineralocorticoides/efeitos adversos , Antagonistas de Receptores de Mineralocorticoides/farmacologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Insuficiência Renal Crônica/terapia
11.
PLoS One ; 16(3): e0248271, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33690712

RESUMO

With the development of the economy and technology, people's requirement for communication is also increasing. Satellite communication networks have been paid more and more attention because of their broadband service capability and wide coverage. In this paper, we investigate the scheme of convolutional long short term memory (CLSTM) network and transfer learning (TL) based combined free/demand assignment multiple access (CFDAMA) scheme (CFDAMA-CLSTMTL), which is a new multiple access scheme in the satellite communication networks. Generally, there is a delay time T between sending a request from the user to the satellite and receiving a reply from the satellite. So far, the traditional multiple access schemes have not processed the data generated in this period. So, in order to transmit the data in time, we propose a new prediction method CLSTMTL, which can be used to predict the data generated in this period. We introduce the prediction method into the CFDAMA scheme so that it can reduce data accumulation by the way of sending the slots request which is the sum of slots requested by the user and the predicted slots generated in the delay time. A comparison with CFDAMA-PA and CFDAMA-PB is provided through simulation results, which gives the effect of the CFDAMA-CLSTMTL in a satellite communication network.

12.
Artigo em Inglês | MEDLINE | ID: mdl-33657003

RESUMO

This study investigates the bipartite fixed-time time-varying output formation-containment tracking issue for heterogeneous linear multiagent systems with multiple leaders. Both cooperative communication and antagonistic communication between neighbor agents are taken into account. First, the bipartite fixed-time compensator is put forward to estimate the convex hull of leaders' states. Different from the existing techniques, the proposed compensator has the following three highlights: 1) it is continuous without involving the sign function, and thus, the chattering phenomenon can be avoided; 2) its estimation can be achieved within a fixed time; and 3) the communication between neighbors can not only be cooperative but also be antagonistic. Note that the proposed compensator is dependent on the global information of network topology. To deal with this issue, the fully distributed adaptive bipartite fixed-time compensator is further proposed. It can estimate not only the convex hull of leaders' states but also the leaders' system matrices. Based on the proposed compensators, the distributed controllers are then developed such that the bipartite time-varying output formation-containment tracking can be achieved within a fixed time. Finally, two examples are given to illustrate the feasibility of the main theoretical findings.

13.
Ann Palliat Med ; 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33691445

RESUMO

BACKGROUND: This study aims to investigate the impacts on the proliferation, inhibition, apoptosis, and cell cycle of hepatic stellate cells (HSC-T6) in rats by using traditional Chinese medicine (TCM) in serum. METHODS: Twenty-seven rats were randomly divided into nine groups on average: a blank control (BC) group (fed by distilled water), a positive control group (colchicine solution, 0.05 mg/mL), and seven TCM groups (with the aim of clearing the liver of choleresis with 0.24 g/mL (weight of TCM herbs per milliliter), 0.73 g/mL, 1.22 g/mL, 2.45 g/mL, 7.34 g/mL, 12.24 g/mL, 24.48 g/mL). Each rat received gavage with a dose of 1 mL/100 g twice a day for 7 days to prepare the drug serum. The HSC-T6 were divided into a TCM serum group, a positive control group, and a BC group. The TCM group and the positive control group were given corresponding drug serum for incubation, while the BC group received the medium without drug serum. RESULTS: The cellular proliferation inhibition rate in the positive control and TCM groups was significantly higher (P<0.01) than that in the BC group. The number of cells in the positive, 0.24 g/mL TCM, 1.22 g/mL TCM, and 7.34 g/mL TCM groups increased significantly (P<0.05) in the G0/G1 phase compared with the BC group. The number of cells in the positive group and all the TCM groups clearly increased in phase S by 0.73 g/mL in the TCM group, 2.45 g/mL in the TCM group, 12.24 g/mL in the TCM group, and 24.48 g/mL in the TCM group compared with the BC group, and the difference was statistically significant (P<0.05). The number of cells in the G2/M phase of the positive control group and all the TCM groups decreased significantly. Compared with the BC group, the positive group, 0.24 g/mL TCM group, 0.73 g/mL TCM group, 1.22 g/mL TCM group, 2.45 g/mL TCM group have statistically difference (P<0.05). CONCLUSIONS: A Qinggan Lidan prescription may exert anti-hepatic fibrosis effects by blocking HSC-T6 in the G0/G1 and S phases and by suppressing the proliferation of HSC-T6.

14.
Water Res ; 196: 117054, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33770677

RESUMO

Dissolved black carbon (DBC), widely found in soil and water environments is likely to affect the transport of nanoplastics in aquatic environments. The aggregation and deposition behaviors of fresh and aged polystyrene nanoplastics (PSs) with and without DBC in NaCl solution were investigated by time-resolved dynamic light scattering (DLS) and quartz crystal microbalance with dissipation monitoring equipment (QCM-D) techniques. The results suggest that DBC can screen the surface charges of PSs by interacting with PSs through hydrogen bonding, hydrophobic interactions and π-π interactions, although they were negatively charged. DBC promoted the aggregation of PSs under relatively low ionic strengths, and it minimally affected the stability of PSs under high ionic strength. Deposition experiments showed that both DBC in salt solution and DBC adsorption on silica surface facilitated the deposition of fresh PSs while HA inhibited both deposition processes. After aging, PSs were more stable, and the effects of DBC and HA were weakened. This study investigated the influence mechanism of DBC on the aggregation and deposition behaviors, which provides new insights into the stability and transport of PSs in complex aquatic environments.

15.
Plant Physiol ; 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33764451

RESUMO

Nitrate acts as a vital signal molecule in the modulation of plant growth and development. The phytohormones gibberellin (GA) is also involved in this process. However, the exact molecular mechanism of how nitrate and GA signaling pathway work together in regulating plant growth remains poorly understood. In this study, we found that a nitrate-responsive BTB/TAZ protein MdBT2 participates in regulating nitrate-induced plant growth in apple (Malus × domestica). Yeast two-hybridization, protein pull-down, and bimolecular fluorescence complementation (BiFC) assays showed that MdBT2 interacts with a DELLA protein MdRGL3a, which is required for the ubiquitination and degradation of MdRGL3a proteins via a 26S proteasome-dependent pathway. Furthermore, heterologous expression of MdBT2 partially rescued growth inhibition caused by overexpression of MdRGL3a in Arabidopsis. Taken together, our findings indicate that MdBT2 promotes nitrate-induced plant growth partially through reducing the abundance of the DELLA protein MdRGL3a.

16.
J Food Sci ; 86(3): 1114-1123, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33565611

RESUMO

A functional yogurt was prepared with Ligustrum robustum (Rxob.) Blume extract (LRE), while its antioxidant and hypoglycemic activities were evaluated and its action mechanism was further explored. With the cofermentation of LRE, the yogurt showed the fine quality characteristics, including pH, titratable acidity, texture, syneresis susceptibility, color, microbiological content, and chemical composition. Meanwhile, the yogurt exhibited the remarkable antioxidant capability to enhance the activities of antioxidant enzymes and reduce the malondialdehyde level in animal serums. In addition, the yogurt showed the obvious hypoglycemic activity to inhibit the decrease of glucose tolerance and the increase of postprandial hyperglycemia of diabetes mice. Furthermore, using the analysis of molecular docking, the main compounds of LRE could combine tightly with α-amylase and α-glucosidase by hydrogen bond and hydrophobic interaction, so as to change their spatial structure and inhibit their biocatalytic activity in glucose metabolism. All present results suggested that LRE showed the potential value to be used as supplement to enhance the quality and functions of yogurt in food industry. PRACTICAL APPLICATION: The hypoglycemic and antioxidant activities of a functional yogurt cofermented with LRE were found and its relative action mechanism was also explored. This work provide the experimental and theoretical basis for the application of this yogurt as nutraceuticals to protect human health in food industry.

17.
Cancer Med ; 10(6): 2164-2174, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33624430

RESUMO

The recognition of adiposity as a risk factor for gastric cancer is mainly based on traditional anthropometric indices, such as body mass index, which are unable to discriminate between lean and fat mass. We undertook this study to examine body composition and subsequent risk of gastric cancer. This is a prospective analysis of participants free of cancer from the UK Biobank. We measured baseline body composition with electrical bioimpedance analysis and confirmed cancer diagnosis through linkage to cancer and death registries. We evaluated hazard ratios (HRs) and confidence interval (CIs) with COX models adjusting for potential confounders. We documented 326 cases of cancer from 474,929 participants over a median follow-up of 6.6 years. Both male (HR 1.70, 95% CI 1.01 to 2.89) and female participants (HR 2.47, 95% CI 1.15 to 5.32) in the highest quartile of whole body fat-free mass were associated with increased risk of gastric cancer as compared with those in the lowest quartile.Whole body fat mass was associated with a decreased risk of gastric cancer (HR per 5-unit increase 0.86, 95% CI 0.74 to 0.99) in females, but not in males. We concluded that fat-free mass and fat mass may have different effects on gastric cancer risk. This study provided evidence for individualized weight management for the prevention of gastric cancer.

18.
J Integr Med ; 19(2): 111-119, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33589406

RESUMO

BACKGROUND: Shenyankangfu Tablet (SYKFT) is a Chinese patent medicine that has been used widely to decrease proteinuria and the progression of chronic kidney disease. OBJECTIVE: This trial compared the efficacy and safety of SYKFT, for the control of proteinuria in primary glomerulonephritis patients, against the standard drug, losartan potassium. DESIGN, SETTING, PARTICIPANTS AND INTERVENTION: This was a multicenter, double-blind, randomized, controlled clinical trial. Primary glomerulonephritis patients, aged 18-70 years, with blood pressure ≤ 140/90 mmHg, estimated glomerular filtration rate (eGFR) ≥ 45 mL/min per 1.73 m2, and 24-hour proteinuria level of 0.5-3.0 g, were recruited in 41 hospitals across 19 provinces in China and were randomly divided into five groups: SYKFT, losartan potassium 50 mg or 100 mg, SYKFT plus losartan potassium 50 mg or 100 mg. MAIN OUTCOME MEASURES: The primary outcome was change in the 24-hour proteinuria level, after 48 weeks of treatment. RESULTS: A total of 735 participants were enrolled. The percent decline of urine protein quantification in the SYKFT group after 48 weeks was 8.78% ± 2.56% (P = 0.006) more than that in the losartan 50 mg group, which was 0.51% ± 2.54% (P = 1.000) less than that in the losartan 100 mg group. Compared with the losartan potassium 50 mg group, the SYKFT plus losartan potassium 50 mg group had a 13.39% ± 2.49% (P < 0.001) greater reduction in urine protein level. Compared with the losartan potassium 100 mg group, the SYKFT plus losartan potassium 100 mg group had a 9.77% ± 2.52% (P = 0.001) greater reduction in urine protein. With a superiority threshold of 15%, neither was statistically significant. eGFR, serum creatinine and serum albumin from the baseline did not change statistically significant. The average change in TCM syndrome score between the patients who took SYKFT (-3.00 [-6.00, -2.00]) and who did not take SYKFT (-2.00 [-5.00, 0]) was statistically significant (P = 0.003). No obvious adverse reactions were observed in any group. CONCLUSION: SYKFT decreased the proteinuria and improved the TCM syndrome scores of primary glomerulonephritis patients, with no change in the rate of decrease in the eGFR. SYKFT plus losartan potassium therapy decreased proteinuria more than losartan potassium therapy alone. TRIAL REGISTRATION NUMBER: NCT02063100 on ClinicalTrials.gov.

19.
J Hazard Mater ; 413: 125374, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33588335

RESUMO

Microcystis aeruginosa (M. aeruginosa) was found to be capable of cadmium (Cd2+) assimilation. Potassium (K+), an essential factor in transmembrane transport, can possibly manipulate the interaction between Cd2+ and M. aeruginosa. In this study, the effect of available K+ levels on Cd2+ toxicity in M. aeruginosa is examined. The results showed that the K+ level was positively linked with toxicity of Cd2+ to M. aeruginosa. And with respect to the M. aeruginosa incubated in K+ = 460 µM treatment, the release of extracellular polymeric substance was augmented, which benefited the retention of Cd2+ on the M. aeruginosa surface. In addition, the assimilation of Cd2+ showed a 3.42-fold increase in comparison to that without K+ supplement. Moreover, the enhanced K+ level caused the up-regulation of the Cd2+ transporting protein and down-regulation of the Cd2+ efflux protein, associated with the positive energy metabolism response. These results documented that the K+ availability could influence the toxicity of Cd2+ to M. aeruginosa jointly through the manipulation of Cd2+ assimilation, excretion, and the biological response. These findings may attach importance to the effects of K+ level on Cd2+ assimilation by M. aeruginosa and shed a degree of light on the enhanced Cd2+ removal using algal-based technology.

20.
Artigo em Inglês | MEDLINE | ID: mdl-33635461

RESUMO

Dissolved organic matter (DOM) plays an important role in aquatic ecosystems. Most previous works have focused on the source, migration, and transformation of DOM in the same water body at several sampling sites, but few studies have focused on the differences in DOM among numerous independent water bodies. This study aimed to investigate the fluorescence properties of DOM and its relationships with water quality indexes, eutrophication levels, and land use in corresponding water catchments in several independent water bodies. Five fluorescent components were identified by the EEM-PARAFAC method in the current study. The UVC humic-like component C1 (λEx/Em = 255/454 nm) and UVA humic-like component C2 (λEx/Em = 260/474 nm) were derived from terrestrial plant decomposition or soil organic matter. The UVA humic-like component C3 (λEx/Em = 300/382 nm) was produced by microbial decomposition. The tryptophan-like component C4 (λEx/Em = 280/330 nm) and the tyrosine-like component C5 (λEx/Em = 225(280)/298 nm) were caused by the discharge of sewage. Farmland contributed more to DOC concentration, humic-like components (C1-C3), and humification index (HIX) than did forest and grassland. The maximum fluorescence intensities of C1, C2, C3, and lna(254) were positively related to the trophic state index (TSI), suggesting that humic-like components and lna(254) could be used as indicators to reflect the eutrophication levels of several independent water bodies.

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