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1.
Nat Commun ; 12(1): 5281, 2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34489402

RESUMO

The archaeal phylum Woesearchaeota, within the DPANN superphylum, includes phylogenetically diverse microorganisms that inhabit various environments. Their biology is poorly understood due to the lack of cultured isolates. Here, we analyze datasets of Woesearchaeota 16S rRNA gene sequences and metagenome-assembled genomes to infer global distribution patterns, ecological preferences and metabolic capabilities. Phylogenomic analyses indicate that the phylum can be classified into ten subgroups, termed A-J. While a symbiotic lifestyle is predicted for most, some members of subgroup J might be host-independent. The genomes of several Woesearchaeota, including subgroup J, encode putative [FeFe] hydrogenases (known to be important for fermentation in other organisms), suggesting that these archaea might be anaerobic fermentative heterotrophs.


Assuntos
Archaea/genética , Proteínas Arqueais/genética , Genoma Arqueal , Hidrogenase/genética , RNA Arqueal/genética , RNA Ribossômico 16S/genética , Sequência de Aminoácidos , Anaerobiose/genética , Archaea/classificação , Archaea/enzimologia , Proteínas Arqueais/metabolismo , Evolução Biológica , Fermentação , Processos Heterotróficos/genética , Hidrogenase/metabolismo , Metagenoma , Filogenia , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
2.
Anal Chem ; 93(32): 11089-11098, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34339167

RESUMO

The need for efficient and accurate identification of pathogens in seafood and the environment has become increasingly urgent, given the current global pandemic. Traditional methods are not only time consuming but also lead to sample wastage. Here, we have proposed two new methods that involve Raman spectroscopy combined with a long short-term memory (LSTM) neural network and compared them with a method using a normal convolutional neural network (CNN). We used eight strains isolated from the marine organism Urechis unicinctus, including four kinds of pathogens. After the models were configured and trained, the LSTM methods that we proposed achieved average isolation-level accuracies exceeding 94%, not only meeting the requirement for identification but also indicating that the proposed methods were faster and more accurate than the normal CNN models. Finally, through a computational approach, we designed a loss function to explore the mechanism reflected by the Raman data, finding the Raman segments that most likely exhibited the characteristics of nucleic acids. These novel experimental results provide insights for developing additional deep learning methods to accurately analyze complex Raman data.


Assuntos
Aprendizado Profundo , Redes Neurais de Computação , Projetos de Pesquisa , Sorogrupo , Análise Espectral Raman
3.
Water Res ; 202: 117490, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364064

RESUMO

Geobacter, as a typical electroactive microorganism, is the "engine" of interspecies electron transfer (IET) between microorganisms. However, it does not have a dominant position in all natural environments. It is not known what performs a similar function as Geobacter in coastal zones. Metagenomic and metatranscriptomic analysis revealed that Desulfovibrio and Methanobacterium species were the most abundant in electrochemically active aggregates. Metatranscriptomic analysis showed that Desulfovibrio species highly expressed genes for ethanol metabolism and extracellular electron transfer involving cytochromes, pili and flagella. Methanobacterium species in the aggregates also expressed genes for enzymes involved in reducing carbon dioxide to methane. Pure cultures demonstrated that the isolated Desulfovibrio sp. strain JY contributed to aggregate conductivity and directly transferred electrons to Methanothrix harundinacea, which is unable to use H2 or formate. Most importantly, further coculture studies indicated that Methanobacterium strain YSL might directly accept electrons from the Desulfovibrio strain JY for the reduction of carbon dioxide to methane in the aggregate. This finding suggested that the possibility of DIET by Desulfovibrio similar to Geobacter species in conductive methanogenic aggregates can not be excluded.


Assuntos
Desulfovibrio , Geobacter , Desulfovibrio/genética , Transporte de Elétrons , Elétrons , Geobacter/genética , Metano , Methanobacterium/genética
4.
Chemosphere ; 286(Pt 3): 131943, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34426266

RESUMO

The wide use of chloramphenicol and its residues in the environments are an increasing threat to human beings. Electroactive microorganisms were proven with the ability of biodegradation of chloramphenicol, but the removal rate and efficiency need to be improved. In this study, a model electricigens, Geobacter metallireducens, was supplied with and Fe3O4 and MnO2 nanoparticles. Five times higher chloramphenicol removal rate (0.71 d-1) and two times higher chloramphenicol removal efficiency (100%) was achieved. Fe3O4 and MnO2 nanoparticles highly increased the current density and NADH-quinone oxidoreductase expression. Fe3O4 nanoparticles enhanced the expression of alcohol dehydrogenase and c-type cytochrome, while MnO2 nanoparticles increased the transcription of pyruvate dehydrogenase and Type IV pili assembly genes. Chloramphenicol was reduced to a type of dichlorination reducing product named CPD3 which is a benzene ring containing compound. Collectively, Fe3O4 and MnO2 nanoparticles increased the chloramphenicol removal capacity in MFCs by enhancing electron transfer efficiency. This study provides new enhancing strategies for the bioremediation of chloramphenicol in the environments.

5.
Hum Vaccin Immunother ; 17(10): 3603-3612, 2021 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-34156312

RESUMO

Introduction: HPV vaccines were administered in mainland China from July 2017 at a gradual rate. We aimed to assess the vaccination rate and vaccination influencing factors among college students in mainland China.Methods: From October to December 2018, we conducted face-to-face questionnaires including 5 sections and 22 questions to collect demographic information, HPV infection and transmission knowledge, HPV vaccine knowledge and attitudes among college students in Guangzhou, China. HPV vaccine vaccination status and cervical screening behaviors were self-reported. Knowledge and attitudes differences between the vaccinate and non-vaccinate groups were analyzed using univariable logistic regression. Vaccination-related influencing factors were estimated using multivariable logistic regression.Results: 5307 of 5414 valid questionnaires were collected. The self-reported cervical screening rate and HPV vaccine coverage were 11.82% (9.03%-14.61%) and 3.09% (2.62%-3.56%). In total, 55.57% of the participants were hesitant about vaccination. Urban residence (OR = 2.1, 95%CI: 1.4-3.3), high monthly consumption (OR = 2.6, 95%CI: 1.9-3.6), awareness of vaccination adaptive population (OR = 3.1, 95%CI: 1.9-5.0), awareness of infection-related risk factors (OR = 2.5, 95%CI: 1.1-5.7), and awareness of HPV vaccine effectiveness (OR = 3.2, 95%CI: 2.0-5.2) were significant in multivariable logistic regression.Conclusion: HPV vaccine coverage is quite low among college students in China Guangzhou. Economic affordability, awareness of HPV infection, and belief in the effectiveness of HPV vaccine are influencing factors for vaccination. In the future, establishing a national financial subsidy and strengthening health education is needed to increase the vaccination rate in China.

6.
Biomed Pharmacother ; 142: 111533, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34148735

RESUMO

Ovarian cancer (OC) is one of the most common gynecologic malignancies with poor survival rate, and Iberin is a member of isothiocyanate family with anti-tumor activity. However, the role of Iberin in OC development has not been reported yet. In this study, A2780 and OVCAR-3 cells were treated with gradient concentrations of Iberin to investigate the effect of Iberin on OC in vitro. Meanwhile, the in vivo tumorgenesis experiment was performed using female BALB/c nude mice treated with Iberin. Iberin inhibited cell proliferation, induced G2 cell cycle arrest and promoted cell apoptosis in OC cells. Besides, Iberin reduced GSH/GSSG level, enhanced ROS accumulation, and activated MAPK signaling in OC cells. More interestingly, ROS scavenger (NAC) compensated the anti-proliferative and pro-apoptotic effects of Iberin on OC cells, suggesting the involvement of ROS in the regulation of Iberin on OC cell growth. Notably, Iberin induced down-regulation of glutathione peroxidase-1 (GPX1), and over-expression of GPX1 reversed Iberin-mediated alterations in the proliferation, apoptosis and ROS accumulation of OC cells. The in vivo tumorgenesis study further evidenced the protection of Iberin against OC development. Besides, Iberin displayed a synergistic effect on the enhancement of chemo-sensitivity in OC cells. In summary, our study demonstrates the anti-tumor effect of Iberin on OC and its potential as a therapeutic agent against OC in the future.

7.
Environ Res ; 200: 111417, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34051197

RESUMO

Biomethane produced by methanogenic archaea is a main greenhouse resource of terrestrial and marine ecosystems, which strongly affects the global environment change. Conductive materials, especially nano-scale, show considerable intervention on biomethane production potential, but the mechanism is still unclear. Herein, we precisely quantified the absolute abundance of Methanosarcina spp. proteins affected by carbon nanotubes (CNTs) using tandem mass tag (TMT) proteomics technology. Among the 927 detectable proteins, more than three hundred, 304, showed differential expression. Gene Set Enrichment Analysis on KEGG pathways and GO biological processes revealed a trend of decreased protein synthesis induced by CNTs, suggesting these conductive nanomaterials may replace part of the cell structure and function. Interestingly, increased acetoclastic methanogenesis actually came at the expense of reduced protein synthesis in related pathways. CNTs stimulated biomethane production from acetate by stimulating intracellular redox activity and the -COOH oxidation process. These findings enhanced the understanding of the biomethane production process affected by conductive materials.


Assuntos
Nanotubos de Carbono , Archaea , Ecossistema , Metano , Nanotubos de Carbono/toxicidade , Proteômica
8.
Eur J Neurol ; 28(8): 2543-2551, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33894037

RESUMO

BACKGROUND AND PURPOSE: Elevated serum matrix metalloproteinase-8 (MMP-8) concentrations are associated with high risk of vascular disease, but the causality remains unclear. A two-sample Mendelian randomization (MR) study was performed to examine the causal effect of serum MMP-8 concentrations on the risk of ischaemic stroke, ischaemic stroke subtypes and coronary artery disease. METHODS: Ten independent single-nucleotide polymorphisms related to serum MMP-8 concentrations were identified as instrumental variables from a genome-wide association study of 6049 European subjects. Genetic association estimates for ischaemic stroke were obtained from the Multiancestry Genome-wide Association Study of Stroke consortium with 446,696 European individuals. The inverse-variance weighted method was applied to assess the causal associations of serum MMP-8 with ischaemic stroke and its subtypes in the main analysis. RESULTS: No significant causal association was observed for MMP-8 levels with total ischaemic stroke, large artery stroke or cardioembolic stroke. Genetically determined 1 - unit higher log-transformed serum MMP-8 concentration was associated with an increased risk of small vessel stroke (odds ratio 1.25; 95% confidence interval 1.12-1.39; p < 0.001). In secondary analysis, a similar adverse impact was reported for MMP-8 on coronary artery disease (odds ratio 1.05; 95% confidence interval 1.01-1.10; p = 0.017). Sensitivity analyses further confirmed the relationship between serum MMP-8 level and small vessel stroke and coronary artery disease. Mendelian randomization Egger regression showed no evidence of pleiotropic bias. CONCLUSIONS: High serum MMP-8 concentrations were causally associated with increased risks of small vessel stroke and coronary artery disease. The mechanism underlying the effect of serum MMP-8 on the vascular system requires further investigation.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Metaloproteinase 8 da Matriz/sangue , Acidente Vascular Cerebral , Isquemia Encefálica/genética , Estudo de Associação Genômica Ampla , Humanos , Análise da Randomização Mendeliana , Polimorfismo de Nucleotídeo Único , Fatores de Risco , Acidente Vascular Cerebral/genética
9.
Environ Sci Pollut Res Int ; 28(29): 39101-39109, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33745054

RESUMO

There is limited and equivocal epidemiological evidence relating to the association between maternal sulfur dioxide (SO2) exposure and the risk of oral clefts (OCs) in offspring. We performed a population-based case-control study in Liaoning province to evaluate aforementioned relationship during 3 months before conception, the first trimester of pregnancy, and their single months. The study involved 3086 patients with OCs and 7950 controls. Data relating to SO2 concentration was acquired from air monitoring stations throughout the study period. We used a multivariable logistic regression model to evaluate the association between exposure to SO2 and the risk of OCs during the exposure windows. Maternal SO2 exposure was positively related to OCs during the 3 months before conception (odds ratio = 1.38, 95% confidence interval: 1.15-1.65; P for trend < 0.01). Positive relationships were obtained from the first and second months before conception and the first month of pregnancy. Thus, our research reflects a relationship between SO2 exposure and the risk of OCs. Future studies are now required to verify the association between SO2 exposure and OCs during pregnancy and indicate the most relevant vulnerable exposure time windows.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Fissura Palatina , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Estudos de Casos e Controles , China/epidemiologia , Fissura Palatina/induzido quimicamente , Fissura Palatina/epidemiologia , Feminino , Humanos , Exposição Materna/efeitos adversos , Dióxido de Nitrogênio , Material Particulado/análise , Gravidez , Dióxido de Enxofre
10.
J Hazard Mater ; 410: 124977, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33422734

RESUMO

Electroactive microorganisms and electrochemical technologies have been separately used for environmental remediation such as antibiotics removal, yet the efficiency of coupling these two methods for chlorinated antibiotics removal is poorly known. Here we tested the synergy of Geobacter sulfurreducens PCA, an electroactive bacteria, and an electrical field, on chloramphenicol removal. Removal is increased two-fold by increasing the temperature from 30°C to 37°C. The cyclic voltammograms and chronoamperometry tests demonstrated that G. sulfurreducens PCA catalyzed chloramphenicol chemical reduction with electrode as excusive electron donor. A critical voltage, -0.6 to -0.5 V vs. Ag/AgCl, was discovered for chloramphenicol degradation with an increase of removal rate about 2.62-folds, from 31.06% to 81.41%. Combined removal with both G. sulfurreducens PCA and an electrical field increased the apparent rate constant and reached 82.77% removal at -0.5 V. Specially, the combined removal at -0.5 V even presented more robust removal efficiency compared to -0.6 V (78.64%) without G. sulfurreducens PCA. Mass spectrometry of degradation products indicates the reduction of nitro into amine groups, and dechlorination into less toxic compounds. Overall, combined biocatalysis and an electrical field is a promising method to remove antibiotics from polluted environments.

11.
Environ Sci Technol ; 54(23): 15347-15354, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-33205658

RESUMO

Direct interspecies electron transfer (DIET) from bacteria to methanogens is a revolutionary concept for syntrophic metabolism in methanogenic soils/sediments and anaerobic digestion. Previous studies have indicated that the potential for DIET is limited to methanogens in the Methanosarcinales, leading to the assumption that an abundance of other types of methanogens, such as Methanobacterium species, indicates a lack of DIET. We report here on a strain of Methanobacterium, designated strain YSL, that grows via DIET in defined cocultures with Geobacter metallireducens. The cocultures formed aggregates, in which cells of strain YSL and G. metallireducens were uniformly dispersed throughout. This close association of the two species is the likely explanation for the ability of a strain of G. metallireducens that could not express electrically conductive pili to grow in coculture with strain YSL. Granular activated carbon promoted the initial formation of the DIET-based cocultures. The discovery of DIET in Methanobacterium, the genus of methanogens that has been the exemplar for interspecies electron transfer via H2, suggests that the capacity for DIET is much more broadly distributed among methanogens than previously considered. More innovative approaches to microbial isolation and characterization are needed in order to better understand how methanogenic communities function.


Assuntos
Geobacter , Methanobacterium , Transporte de Elétrons , Elétrons , Metano
12.
ISME J ; 14(11): 2829-2842, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32814865

RESUMO

Mutualisms between symbiotic microbes and animals have been well documented, and nutritional relationships provide the foundation for maintaining beneficial associations. The well-studied mutualism between bark beetles and their fungi has become a classic model system in the study of symbioses. Despite the nutritional competition between bark beetles and beneficial fungi in the same niche due to poor nutritional feeding substrates, bark beetles still maintain mutualistic associations with beneficial fungi over time. The mechanism behind this phenomenon, however, remains largely unknown. Here, we demonstrated the bark beetle Dendroctonus valens LeConte relies on the symbiotic bacterial volatile ammonia, as a nitrogen source, to regulate carbohydrate metabolism of its mutualistic fungus Leptographium procerum to alleviate nutritional competition, thereby maintaining the stability of the bark beetle-fungus mutualism. Ammonia significantly reduces competition of L. procerum for carbon resources for D. valens larval growth and increases fungal growth. Using stable isotope analysis, we show the fungus breakdown of phloem starch into D-glucose by switching on amylase genes only in the presence of ammonia. Deletion of amylase genes interferes with the conversion of starch to glucose. The acceleration of carbohydrate consumption and the conversion of starch into glucose benefit this invasive beetle-fungus complex. The nutrient consumption-compensation strategy mediated by tripartite beetle-fungus-bacterium aids the maintenance of this invasive mutualism under limited nutritional conditions, exacerbating its invasiveness with this competitive nutritional edge.


Assuntos
Besouros , Ophiostomatales , Pinus , Gorgulhos , Animais , Simbiose
13.
Occup Environ Med ; 77(10): 721-727, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32737151

RESUMO

BACKGROUND: Current literature describes limited and controversial evidence on the associations between maternal preconception and first trimester exposure to particulate matter with a diameter ≤10 µm (PM10) and the risk of oral cleft (OC). METHODS: We conducted a case-control study involving 3086 OC cases and 7950 controls, registered in the Maternal and Child Health Certificate Registry in Liaoning Province between 2010 and 2015. PM10 concentrations were obtained from the Environment Protection Bureau. The exposure windows included the 3 months before pregnancy, the first trimester and the individual months. Unconditional logistic regression model was performed to estimate the OR and 95% CI for the association between PM10 exposure and the risk of OC, cleft lip only (CLO), cleft palate only (CPO), and cleft lip and palate (CLP). RESULTS: Maternal PM10 exposure was positively associated with an increased risk for OC during the 3 months preconception (per 10 µg/m3 increment: OR=1.04, 95% CI 1.01 to 1.07; highest vs lowest quartile: OR=1.23, 95% CI 1.04 to 1.45) and the first trimester (per 10 µg/m3 increment: OR=1.05, 95% CI 1.02 to 1.08; highest vs lowest quartile: OR=1.37, 95% CI 1.15 to 1.64). Analyses based on individual months presented similar positive associations, particularly in the second month of pregnancy (OR=1.77, 95% CI 1.51 to 2.09) for highest versus lowest quartile. In the subtype analysis, stronger associations were observed for CLO, whereas there was negligible evidence for CPO and CLP. Sensitivity analyses using propensity score matching generated similar findings. CONCLUSIONS: Our study provides evidence that PM10 exposure during the 3 months preconception and the first trimester increases the risk of OC.


Assuntos
Fissura Palatina/diagnóstico , Material Particulado/efeitos adversos , Lesões Pré-Concepcionais/etiologia , Primeiro Trimestre da Gravidez , Poluição do Ar/efeitos adversos , Estudos de Casos e Controles , China/epidemiologia , Fissura Palatina/epidemiologia , Fissura Palatina/etiologia , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Modelos Logísticos , Lesões Pré-Concepcionais/epidemiologia , Gravidez , Fatores de Risco
14.
Ann Intern Med ; 173(11): 879-887, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-32790510

RESUMO

BACKGROUND: Risk for transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to close contacts of infected persons has not been well estimated. OBJECTIVE: To evaluate the risk for transmission of SARS-CoV-2 to close contacts in different settings. DESIGN: Prospective cohort study. SETTING: Close contacts of persons infected with SARS-CoV-2 in Guangzhou, China. PARTICIPANTS: 3410 close contacts of 391 index cases were traced between 13 January and 6 March 2020. Data on the setting of the exposure, reverse transcriptase polymerase chain reaction testing, and clinical characteristics of index and secondary cases were collected. MEASUREMENT: Coronavirus disease 2019 (COVID-19) cases were confirmed by guidelines issued by China. Secondary attack rates in different settings were calculated. RESULTS: Among 3410 close contacts, 127 (3.7% [95% CI, 3.1% to 4.4%]) were secondarily infected. Of these 127 persons, 8 (6.3% [CI, 2.1% to 10.5%]) were asymptomatic. Of the 119 symptomatic cases, 20 (16.8%) were defined as mild, 87 (73.1%) as moderate, and 12 (10.1%) as severe or critical. Compared with the household setting (10.3%), the secondary attack rate was lower for exposures in health care settings (1.0%; odds ratio [OR], 0.09 [CI, 0.04 to 0.20]) and on public transportation (0.1%; OR, 0.01 [CI, 0.00 to 0.08]). The secondary attack rate increased with the severity of index cases, from 0.3% (CI, 0.0% to 1.0%) for asymptomatic to 3.3% (CI, 1.8% to 4.8%) for mild, 5.6% (CI, 4.4% to 6.8%) for moderate, and 6.2% (CI, 3.2% to 9.1%) for severe or critical cases. Index cases with expectoration were associated with higher risk for secondary infection (13.6% vs. 3.0% for index cases without expectoration; OR, 4.81 [CI, 3.35 to 6.93]). LIMITATION: There was potential recall bias regarding symptom onset among patients with COVID-19, and the symptoms and severity of index cases were not assessed at the time of exposure to contacts. CONCLUSION: Household contact was the main setting for transmission of SARS-CoV-2, and the risk for transmission of SARS-CoV-2 among close contacts increased with the severity of index cases. PRIMARY FUNDING SOURCE: Guangdong Province Higher Vocational Colleges and Schools Pearl River Scholar Funded Scheme.


Assuntos
COVID-19/transmissão , Busca de Comunicante , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/epidemiologia , Teste para COVID-19 , Criança , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Pandemias , Estudos Prospectivos , Fatores de Risco , SARS-CoV-2 , Índice de Gravidade de Doença
15.
Front Microbiol ; 11: 1770, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32849394

RESUMO

Methanogens are the major contributors of greenhouse gas methane and play significant roles in the degradation and transformation of organic matter. These organisms are particularly abundant in Swan Lake, which is a shallow lagoon located in Rongcheng Bay, Yellow Sea, northern China, where eutrophication from overfertilization commonly results in anoxic environments. High organic phosphorus content is a key component of the total phosphorus in Swan Lake and is possibly a key factor affecting the eutrophication and carbon and nitrogen cycling in Swan Lake. The effects of organic phosphorus on eutrophication have been well-studied with respect to bacteria, such as cyanobacteria, unlike the effects of organic phosphorus on methanogenesis. In this study, different sediment layer samples of seagrass-vegetated and unvegetated areas in Swan Lake were investigated to understand the effects of organic phosphorus on methylotrophic methanogenesis. The results showed that phytate phosphorus significantly promoted methane production in the deepest sediment layer of vegetated regions but suppressed it in unvegetated regions. Amplicon sequencing revealed that methylotrophic Methanococcoides actively dominated in all enrichment samples from both regions with additions of trimethylamine or phytate phosphorus, whereas methylotrophic Methanolobus and Methanosarcina predominated in the enrichments obtained from vegetated and unvegetated sediments, respectively. These results prompted further study of the effects of phytate phosphorus on two methanogen isolates, Methanolobus psychrophilus, a type strain, Methanosarcina mazei, an isolate from Swan Lake sediments. Cultivation experiments showed that phytate phosphorus could inhibit methane production by M. psychrophilus but promote methane production by M. mazei. These culture-based studies revealed the effects of organic phosphorus on methylotrophic methanogenesis in coastal lagoon sediments and improves our understanding of the mechanisms of organic carbon cycling leading to methanogenesis mediated by organic phosphorus dynamics in coastal wetlands.

16.
Anal Chem ; 92(15): 10402-10411, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32614167

RESUMO

Direct interspecies electron transfer (DIET) has been considered as a novel and highly efficient strategy in both natural anaerobic environments and artificial microbial fuel cells. A syntrophic model consisting of Geobacter metallireducens and Geobacter sulfurreducens was studied in this work. We conducted in vivo molecular mapping of the outer surface of the syntrophic community as the interface of nutrients and energy exchange. System for Analysis at the Liquid Vacuum Interface combined with time-of-flight secondary ion mass spectrometry was employed to capture the molecular distribution of syntrophic Geobacter communities in the living and hydrated state. Principal component analysis with selected peaks revealed that syntrophic Geobacter aggregates were well differentiated from other control samples, including syntrophic planktonic cells, pure cultured planktonic cells, and single population biofilms. Our in vivo imaging indicated that a unique molecular surface was formed. Specifically, aromatic amino acids, phosphatidylethanolamine components, and large water clusters were identified as key components that favored the DIET of syntrophic Geobacter aggregates. Moreover, the molecular changes in depths of the Geobacter aggregates were captured using dynamic depth profiling. Our findings shed new light on the interface components supporting electron transfer in syntrophic communities based on in vivo molecular imaging.


Assuntos
Aminoácidos Aromáticos/metabolismo , Geobacter/fisiologia , Espectrometria de Massas/métodos , Imagem Molecular/métodos , Fosfatidiletanolaminas/metabolismo , Aminoácidos Aromáticos/química , Biofilmes , Transporte de Elétrons , Fosfatidiletanolaminas/química , Análise de Componente Principal , Água/química , Água/metabolismo
17.
Appl Opt ; 59(10): C87-C91, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32400569

RESUMO

We have demonstrated a dual-wavelength blue-green laser for airborne ocean lidar based on an all-solid-state master oscillator power amplifier and nonlinear frequency conversion methods. A Q-switched pulsed laser with 10 mJ energy at 1064 nm was amplified to 108 mJ by a Nd:YAG amplifier side pumped by vertical-cavity surface-emitting laser modules. This fundamental laser was then frequency tripled to 355 nm wavelength by lithium triborate (LBO) crystals. With maximum pump energy of 43.5 mJ at 355 nm, 9.6 mJ of blue laser pulse at 486.1 nm was successfully obtained from an optical parametric oscillator unit using two beta-barium borate crystals. The energy of the residual 532 nm laser pulse was 10.6 mJ. Equipped with this laser system, an airborne blue-green lidar was developed, and ocean detection was carried out in the South China Sea, where an optical vertical profile at seawater depth of 94 m was obtained.

18.
Sci Total Environ ; 726: 138477, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32315848

RESUMO

Rapid identification of marine pathogens is very important in marine ecology. Artificial intelligence combined with Raman spectroscopy is a promising choice for identifying marine pathogens due to its rapidity and efficiency. However, considering the cost of sample collection and the challenging nature of the experimental environment, only limited spectra are typically available to build a classification model, which hinders qualitative analysis. In this paper, we propose a novel method to classify marine pathogens by means of Raman spectroscopy combined with generative adversarial networks (GANs). Three marine strains, namely, Staphylococcus hominis, Vibrio alginolyticus, and Bacillus licheniformis, were cultured. Using Raman spectroscopy, we acquired 100 spectra of each strain, and we fitted them into GAN models for training. After 30,000 training iterations, the spectra generated by G were similar to the actual spectra, and D was used to test the accuracy of the spectra. Our results demonstrate that our method not only improves the accuracy of machine learning classification but also solves the problem of requiring a large amount of training data. Moreover, we have attempted to find potential identifying regions in the Raman spectra that can be used for reference in subsequent related work in this field. Therefore, this method has tremendous potential to be developed as a tool for pathogen identification.


Assuntos
Inteligência Artificial , Análise Espectral Raman , Aprendizado de Máquina
19.
Chemosphere ; 254: 126813, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32334261

RESUMO

TiO2/cement composites were prepared by a spraying method to degrade organic pollutants. After coated with waterproof liquid, pure cement pastes/mortars were sprayed with TiO2 suspensions with different TiO2 contents and spraying times. Photocatalytic properties, mechanical strength and durability were studied. Maximum photocatalytic activity and uniform TiO2 distribution were achieved at the optimal conditions of 10 wt% TiO2 content in suspension and 3 spraying times. The TiO2/cement pastes had better degradation performance over Rhodamine B (RhB) and methylene blue (MB) than that over methyl orange (MO). After 20 times of cycling degradation, the photocatalytic efficiencies had no significant reduction. The TiO2/cement mortars had good mechanical strengths, meeting the mechanical demands of wastewater treatment tanks. In durability, the TiO2/cement mortars had better water penetration resistance, chloride penetration resistance and anti-carbonation than pure cement mortars.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Compostos Azo , Catálise , Poluentes Ambientais , Azul de Metileno , Rodaminas , Titânio/química , Raios Ultravioleta , Águas Residuárias
20.
Food Chem ; 303: 125378, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31450176

RESUMO

This work introduces an inexpensive and user-friendly electrochemical platform for heavy metal determination in liquid food. Smart-phone connectivity, solid-state-microwave flow digestion and nano-Au-modified electrode are synchronously studied. A smart phone is adopted as the information terminal for universal purposes. A solid-state-microwave digestion device is developed to provide programmable digestion for liquid food in a digestion path. Microwave power curve and flow rate in digestion are studied and optimized. A nano-Au-modified electrode, as well as a homemade potentiostat and other electrodes, is used as a tool for electrochemical analyses. Behaviors of this method are evaluated with electrical measurement and stripping voltammetry. This method is used for sensing Cd2+, Pb2+ and Hg2+ in cow milk, orange juice and apple juice. It provides a sensitive response to ≥2 µg L-1 target ion, and shows satisfying stability and good accuracy in a task up to 72 h.


Assuntos
Técnicas Eletroquímicas/métodos , Sucos de Frutas e Vegetais/análise , Metais Pesados/análise , Leite/química , Smartphone , Animais , Cádmio/análise , Bovinos , Eletrodos , Feminino , Ouro/química , Chumbo/análise , Mercúrio/análise , Micro-Ondas
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