Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
BMC Geriatr ; 23(1): 281, 2023 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-37165340

RESUMO

BACKGROUND: Dietary-induced inflammation is potentially associated with sarcopenia. Nevertheless, few studies have investigated the structure of the inflammatory diet and its correlation with muscle function and performance in both the upper and lower limbs. This study was performed to explore the association of the dietary inflammatory index (DII) with sarcopenia and its diagnostic parameters. METHODS: We conducted a cross-sectional survey on a sample of 515 Chinese community-dwelling older adults selected through multistage cluster sampling from three districts in Shanghai. DII scores were calculated using a validated food frequency questionnaire. Sarcopenia and its diagnostic parameters were determined based on the definition set by the Asian Working Group on Sarcopenia (AWGS). RESULTS: The mean age of study participants was 71.31 ± 4.71 years. The prevalence of sarcopenia in the cohort was 12.4%. Older adults in the highest DII quartile had a 3.339 times increased risk of sarcopenia compared to those in the lowest quartile (OR Quartile4vs1:3.339, 95%CI: 1.232, 9.052, p-trend: 0.004) after adjusting for confounding factors. Additionally, a more pro-inflammatory diet was associated with lower appendicular skeletal muscle index (ASMI) (OR Quartile4vs1: 3.005, 95%CI: 1.275, 7.318, p-trend: 0.005), a higher 5-times sit-stand test time score (OR Quartile4vs1: 4.942, 95%CI: 1.745, 13.993, p-trend: 0.005), and lower gait speed (OR Quartile4vs1: 2.392, 95%CI: 1.104, 5.185, p-trend: 0.041) after adjusting for confounding factors. However, there was no significant association between DII, handgrip strength, and Short Physical Performance Battery (SPPB) score in either the unadjusted or adjusted model. CONCLUSION: This study found that the association between consuming a more pro-inflammatory diet and sarcopenia in Chinese community-dwelling older adults was mainly due to underlying low intakes of dietary energy, protein, and anti-inflammatory foods, and not due to the high intake of pro-inflammatory foods. Meanwhile, DII was more highly correlated with lower limb muscle strength and performance compared to upper limb muscle strength.


Assuntos
Sarcopenia , Idoso , Humanos , China , Estudos Transversais , Dieta/efeitos adversos , População do Leste Asiático , Força da Mão , Sarcopenia/diagnóstico , Sarcopenia/epidemiologia , Vida Independente
2.
Lett Appl Microbiol ; 76(1)2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36688790

RESUMO

Microbially driven Fe(II) oxidation is vital for Fe-cycling processes. In the present study, a novel strain of nitrate-dependent Fe-oxidizing bacteria (FOB) was isolated from the riparian zone sediment of the Hanjiang River, China. It was identified as Comamonas terrigena strain HJ-2. The strain HJ-2 oxidized 2.80 mmol l-1 Fe(II) within 144 h to form Fe(III)/Fe(II) complex on the cell surface using 1.63 mmol l-1 nitrate as an electron acceptor. The formed nitrite from nitrate reduction chemically oxidized Fe(II). Surprisingly, this strain also reduced nitrilotriacetic iron to form 0.5 mmol l-1 Fe(II) in 120 h in anaerobic conditions primarily mediated by the NADH flavin oxidoreductase. Besides, the strain completely reduced 0.18 mmol l-1 nitrobenzene to aniline in 24 days and 15.6 µmol l-1 arsenate to arsenite in 7 days due to the existence of nitro and arsenate reductases. However, the Fe(II) inhibited the reduction of nitrate, nitrobenzene, and arsenate, possibly due to the impeding of transport of the solutes through the membrane or the synthesis of the related enzymes. These results provide new knowledge about the Fe(II)-cycling and the fate of some pollutants in the riparian zone. It also informed that some bacteria have universal functions on elements and contaminants transformation.


Assuntos
Comamonas , Nitratos , Nitratos/metabolismo , Arseniatos/metabolismo , Compostos Férricos/metabolismo , Compostos Ferrosos/metabolismo , Comamonas/metabolismo , Bactérias/metabolismo , Oxirredução
3.
Macromol Rapid Commun ; 43(8): e2100854, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35254691

RESUMO

Photodetectors based on reduced graphene oxide (rGO) have attracted much attention owing to their simple and low-cost fabrication process. However, the aggregation and defects of rGO flakes still limit the performance of rGO photodetectors. Controlling the composition of rGO has become a vital factor for its prospective applications. For example, the interconnection between rGO and polymers for modified morphologies of rGO films leads to an enhanced performance of devices. In this work, a practical approach to engineer surface uniformity and enhance the performance of a photodetector by modifying the rGO film with hydrophilic polymers poly(vinyl alcohol) (PVA) is reported. Compared with the rGO photodetector, the on/off ratio for the PVA/rGO photodetector shows 3.5 times improvement, and the detectivity shows 53% enhancement even when the photodetector is operated at a low bias of 0.3 V. This study provides an effective route to realize PVA/rGO photodetectors with a low-power operation which shows promising opportunities for the future development of green systems.

4.
Biotechnol Lett ; 44(1): 33-44, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34820721

RESUMO

Since prokaryotic restriction-modification (RM) systems protect the host by cleaving foreign DNA by restriction endonucleases, it is difficult to introduce engineered plasmid DNAs into newly isolated microorganisms whose RM system is not discovered. The prokaryotes also possess methyltransferases to protect their own DNA from the endonucleases. As those methyltransferases can be utilized to methylate engineered plasmid DNAs before transformation and to enhance the stability within the cells, the study on methyltransferases in newly isolated bacteria is essential for genetic engineering. Here, we introduce the mechanism of the RM system, specifically the methyltransferases and their biotechnological applications. These biotechnological strategies could facilitate plasmid DNA-based genetic engineering in bacteria strains that strongly defend against foreign DNA.


Assuntos
Metilação de DNA , Metiltransferases , Bactérias/genética , Biotecnologia , DNA Bacteriano/genética , Metiltransferases/genética
5.
Environ Sci Technol ; 52(4): 2385-2391, 2018 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-29390188

RESUMO

The control of toxic chromate (Cr6+) formation is still a significant challenge in solid fuel combustion. In particular, the mechanism of chromium transformation from Cr3+ to chromate or other unoxidized forms remains unclear. The present study confirms the formation of a significant unoxidized Cr-containing compound CaCr2O4(Cr3+) during solid fuel combustion. Experiments were conducted, for the first time, to clarify the mechanism of CaCr2O4 oxidation, which is quite different from Cr2O3 oxidation. The findings demonstrate that CaCr2O4 was formed at temperatures above 1200 K, through rapid decomposition of CaCrO4 or slow and direct interaction between CaO and Cr2O3. Compared to Cr2O3, CaCr2O4 could be oxidized at lower temperatures under the influence of free CaO. In the absence of free CaO, the oxidation of CaCr2O4 was minimal; however, in the presence of CaSO4, calcium in the form of CaCr2O4 participated in the oxidation of CaCr2O4. Thus, chromium in the form of CaCr2O4 was more likely to be oxidized when CaCr2O4-containing fly ash was reheated. Fortunately, CaCr2O4 showed slight basicity on the surface, allowing it to react with acidic gases. Accordingly, measures were proposed to suppress the oxidation of CaCr2O4 by stimulating the reactions between CaCr2O4 and acidic substances, like SO2 and Si/Al-compounds. These compounds competed with chromium at high temperatures to react with calcium in the fly ash and in CaCr2O4. As a result, the unoxidized chromium was transformed into highly stable Cr2O3 or Ca3Cr2 (SiO4)3.


Assuntos
Cromo , Cinza de Carvão , Gases , Oxirredução , Temperatura
6.
Mol Biol Rep ; 41(9): 6097-104, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24996285

RESUMO

Diosgenin is a steroid derived from cholesterol in plants and used as a typical initial intermediate for synthesis of numerous steroidal drugs in the world. Commercially, this compound is extracted mainly from the rhizomes or tubers of some Dioscorea species. Squalene synthase (SQS: EC 2.5.1.21) catalyzes the condensation of two molecules of farnesyl diphosphate to form squalene, the first committed step for biosynthesis of plant sterols including cholesterol, and is thought to play an important role in diosgenin biosynthesis. A full-length cDNA of a putative squalene synthase gene was cloned from D. zingiberensis and designated as DzSQS (Genbank Accession Number KC960673). DzSQS was contained an open reading frame of 1,230 bp encoding a polypeptide of 409 amino acids with a predicted molecular weight of 46 kDa and an isoelectric point of 6.2. The deduced amino acid sequence of DzSQS shared over 70 % sequence identity with those of SQSs from other plants. The truncated DzSQS in which 24 amino acids were deleted from the carboxy terminus was expressed in Escherichia coli, and the resultant bacterial crude extract was incubated with farnesyl diphosphate and NADPH. GC-MS analysis showed that squalene was detected in the in vitro reaction mixture. Quantitative real-time PCR analysis revealed that DzSQS was expressed from highest to lowest order in mature leaves, newly-formed rhizomes, young leaves, young stems, and two-year-old rhizomes of D. zingiberensis.


Assuntos
Dioscorea/genética , Farnesil-Difosfato Farnesiltransferase/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Clonagem Molecular , Dioscorea/enzimologia , Farnesil-Difosfato Farnesiltransferase/química , Farnesil-Difosfato Farnesiltransferase/metabolismo , Regulação Enzimológica da Expressão Gênica , Dados de Sequência Molecular , Especificidade de Órgãos , Folhas de Planta/genética , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Caules de Planta/genética , Plantas Medicinais/enzimologia , Plantas Medicinais/genética , Fosfatos de Poli-Isoprenil/metabolismo , Rizoma/genética , Sesquiterpenos/metabolismo
7.
Chemosphere ; 316: 137797, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36634713

RESUMO

Transition metal doped WO3 mixed oxides (named as W-M-O, M = Nb, Fe, Cr, Cu, Ti or Sn, respectively) with high structure stability were synthesized by modified sol-gel method using citric acid as organic crosslinking agent, and were evaluated for catalytic elimination of low-concentration toluene, monochlorobenzene and 1,2-dichloroethance with high toxicity and relatively stable molecule structure, as the typical examples for the pollutants of various volatile organic compounds (VOCs). Results of the structure-property-performance relationship research showed that mesoporous structure and nanocrystalline/amorphous state were formed, and binary metal components were dispersed into each other, which contributed to promoting the metal/metal electron interaction and adjusting the physicochemical properties of mixed metal oxides. The sequence of apparent catalytic activity for toluene degradation was: W-Nb-O>W-Fe-O>W-Cr-O, W-Cu-O>W-Ti-O>W-Sn-O>WO3, and the sequence for monochlorobenzene degradation was: W-Nb-O>W-Fe-O>W-Cr-O, W-Ti-O>W-Cu-O>W-Sn-O>WO3. There existed cooperative catalytic effect: mesopore and surface acid sites of catalysts facilitated adsorption, activation and breakage of the C-X bond, and then redox sites of catalysts promoted deep oxidation of a series of reaction intermediates to transform into CO2 and H2O. Especially, the optimized W-Nb-O catalyst deserved more attention, since it represented remarkable catalytic activity, selectivity and durability for three typical VOCs degradation along with good resistance to water vapor and corrosion of HCl.


Assuntos
Poluentes Ambientais , Elementos de Transição , Óxidos/química , Clorobenzenos , Oxirredução , Metais/química , Catálise , Tolueno/química
8.
Sci Total Environ ; 857(Pt 2): 159539, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36265633

RESUMO

The anammox-based process has been considered a promising biological nitrogen elimination method for the treatment of nitrogen-rich wastewater ever since its discovery 40 years ago. However, the slow growth rate of anammox bacteria and severe sludge washout result in a long startup period and limit its widespread industrial application. A membrane bioreactor (MBR) is considered an ideal reactor for the operation of the anammox-based process because the membranes allow for 100 % biomass retention. According to a systematic review of the literature, anammox-based MBR is becoming a research hotspot in the field of nitrogen wastewater treatment. The fundamental understanding of anammox-based MBR and its membrane fouling situation is essential for the development and application of anammox-based MBR. In this paper, the application of MBR in different kinds of anammox process are reviewed. The membrane fouling mechanism and strategies to control membrane fouling are also proposed. It is expected that this review will serve as an invaluable guide for future research and in the engineering applications of anammox-based MBR process.


Assuntos
Oxidação Anaeróbia da Amônia , Reatores Biológicos , Reatores Biológicos/microbiologia , Esgotos/microbiologia , Águas Residuárias , Nitrogênio , Membranas Artificiais
9.
Bioresour Technol ; 367: 128229, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36332864

RESUMO

A novel two-stage process comprising pre-denitrification and single-stage partial nitritation/anammox was developed to treat swine manure digestate with a constant nitrogen loading rate of 1.0 gN/L/d. As the influent NH4+-N concentration increased from 500 to 1500 mg/L, a nitrogen removal efficiency of 88 %-96 % and 5-day biochemical oxygen demand removal efficiency of 93 %-97 % were achieved. Owing to the high influent chemical oxygen demand (COD)/nitrates and nitrites (NOX) ratio of 8.2-9.2 and high COD utilization of denitrifying bacteria (DB), the NO2--N and NO3--N removal efficiencies in the denitrification reactor reached 96 %-99 % and 97 %-99 %, respectively. The contribution of anammox bacteria to nitrogen removal was 70.9 %-84.3 %, whereas that of DB was 11.7 %-18.3 %. The contributions of DB and ordinary heterotrophic organisms to COD removal were 19.5 %-49.3 % and 17.9 %-39 %, respectively. This study will help guide the anammox process in swine wastewater treatment.


Assuntos
Desnitrificação , Nitrogênio , Suínos , Animais , Esterco , Reatores Biológicos/microbiologia , Oxidação Anaeróbia da Amônia , Oxirredução , Bactérias , Águas Residuárias/microbiologia , Esgotos
10.
ACS Appl Mater Interfaces ; 15(10): 13380-13392, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36853974

RESUMO

As an attractive prototype for neuromorphic computing, the difficultly attained three-terminal platforms have specific advantages in implementing the brain-inspired functions. Also, in these devices, the most utilized mechanisms are confined to the electrical gate-controlled ionic migrations, which are sensitive to the device defects and stoichiometric ratio. The resultant memristive responses have fluctuant characteristics, which have adverse influences on the neural emulations. Herein, we designed a specific transistor platform with light-regulated ambipolar memory characteristics. Also, based on its gentle processes of charge trapping, we obtain the impressive memristive performances featured by smooth responses and long-term endurable characteristics. The optoelectronic samples were also fabricated on flexible substrates successfully. Interestingly, based on the optoelectronic signals of the flexible devices, we endow the desirable optical processes with the brain-inspired emulations. We can flexibly emulate the light-inspired learning-memory functions in a synapse and further devise the advanced synapse array. More importantly, through this versatile platform, we investigate the mutual regulation of excitation and inhibition and implement their sensitive-mode transformations and the homeostasis property, which is conducive to ensuring the stability of overall neural activity. Furthermore, our flexible optoelectronic platform achieves high classification accuracy when implemented in artificial neural network simulations. This work demonstrates the advantages of the optoelectronic platform in implementing the significant brain-inspired functions and provides an insight into the future integration of visible sensing in flexible optoelectronic transistor platforms.

11.
Front Nutr ; 10: 1104255, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37081917

RESUMO

Background: Some studies have shown that a pro-inflammatory diet may be associated with cognitive function, but their conclusions have varied considerably. We here present a meta-analysis of the current published literature on DII score and its association with cognitive health. Methods: In this meta-analysis, the PubMed, Embase, Web of Science, and Cochrane databases were searched in September 2022. The reported indexes, specifically OR, RR, and ß, were extracted and analyzed using R version 3.1.0. Results: A total of 636 studies in databases were identified, and 12 were included in the meta-analysis. Higher DII was associated with an increased risk of AD and MCI (OR = 1.34; 95% CI = 1.21-1.49). Meanwhile, it may also cause global function impairment (categorical: OR = 1.63; 95% CI = 1.36-1.96) and verbal fluency impairment (continuous: OR = 0.18; 95% IC = 0.08-0.42). But there was no significant association between DII and executive function (categorical: OR = 1.12; 95% IC = 0.84-1.49; continuous: OR = 0.48; 95% IC = 0.19-1.21) or episodic memory (continuous: OR = 0.56; 95% IC = 0.30-1.03). Conclusion: A pro-inflammatory diet is related to AD, MCI, and the functions of some cognitive domains (specifically global function and verbal fluency). However, the current evidence on the role of diet-induced inflammation in different cognitive domains should be supported by further studies in the future.

12.
Bioresour Technol ; 386: 129494, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37460018

RESUMO

This study evaluated the functional activity and microbial structure of a pre-denitrification and single-stage partial nitritation/anammox process (DB-SNAP) coupled system for effectively treating swine manure digestate (SMD). At influent ammonium concentrations of (1000 to 1500) mg/L, the pre-denitrification reactor increased the nitrogen removal efficiency (NRE) by 5%, resulting in an average NRE of 96%. The DB-SNAP and nitrogen-limited strategy facilitated the rapid adoption of anammox bacteria (AnAOB) in the SMD, maintaining a high specific rate of 0.3gN/gVSS/d. A high secretion of tightly bound extracellular polymeric substances (76 mg/gVSS to 102 mg/gVSS) promoted micro-granule aggregation and stability. Moreover, Ca. Kuenenia, an AnAOB genus, was highly enriched from 21% to (27 to 30) %, whereas Nitrospira, a nitrite-oxidizing bacteria, was significantly suppressed to (0 to 0.05) %. These findings will provide valuable guidance in implementing the anammox process in swine wastewater treatment.


Assuntos
Compostos de Amônio , Desnitrificação , Animais , Suínos , Esterco , Nitrogênio , Oxidação Anaeróbia da Amônia , Reatores Biológicos/microbiologia , Oxirredução , Bactérias , Esgotos
13.
J Microbiol Biotechnol ; 33(7): 973-979, 2023 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-37100763

RESUMO

Lycopene is a carotenoid widely used as a food and feed supplement due to its antioxidant, anti-inflammatory, and anti-cancer functions. Various metabolic engineering strategies have been implemented for high lycopene production in Escherichia coli, and for this purpose it was essential to select and develop an E. coli strain with the highest potency. In this study, we evaluated 16 E. coli strains to determine the best lycopene production host by introducing a lycopene biosynthetic pathway (crtE, crtB, and crtI genes cloned from Deinococcus wulumuqiensis R12 and dxs, dxr, ispA, and idi genes cloned from E. coli). The 16 lycopene strain titers diverged from 0 to 0.141 g/l, with MG1655 demonstrating the highest titer (0.141 g/l), while the SURE and W strains expressed the lowest (0 g/l) in an LB medium. When a 2 × YTg medium replaced the MG1655 culture medium, the titer further escalated to 1.595 g/l. These results substantiate that strain selection is vital in metabolic engineering, and further, that MG1655 is a potent host for producing lycopene and other carotenoids with the same lycopene biosynthetic pathway.


Assuntos
Carotenoides , Escherichia coli , Licopeno/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Carotenoides/metabolismo , Antioxidantes/metabolismo , Engenharia Metabólica
14.
Org Lett ; 25(1): 104-108, 2023 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-36583996

RESUMO

An asymmetric linear selective allylic alkylation of vinylaziridines with 3-aryl oxindoles has been developed by using a chiral oxamide-phosphine (COAP-Bn-OMe-p)/palladium complex in methanol, which furnished a wide variety of 3,3-disubstituted oxindole derivatives in good yields with excellent regio- and enantioselectivities.


Assuntos
Paládio , Oxindóis , Paládio/química , Catálise , Estereoisomerismo , Alquilação
15.
Z Naturforsch C J Biosci ; 67(3-4): 195-207, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22624336

RESUMO

Amorpha-4,11-diene is the precursor of the antimalarial compound artemisinin. The effect of Vitreoscilla hemoglobin (VHb) and its yeast-conform variant (VHbm) on amorpha-4,11-diene production in engineered Saccharomyces cerevisiae was investigated. First, the VHb gene was mutated to the yeast-conform variant VHbm based on step-by-step extension of a short region of the gene through a series of polymerase chain reactions (PCR). The artificial VHbm gene contained codons preferred by the yeast translation machinery. Two yeast expression vectors containing VHb or VHbm gene were constructed and introduced into the amorpha-4,11-diene-producing strain S. cerevisiae WK1 to form WK1[VHb] and WK1[VHbm], respectively. Western blot and CO-difference spectrum absorbance assay showed that VHb and VHbm were successfully expressed. In shake flasks, VHbm expression conferred higher cell growth than VHb expression. GC-MS results indicated the amorpha-4,11-diene production in WK1[VHbm] and WK1[VHb] was 3- and 2-fold higher than that in WK1, respectively. This suggests that VHb might improve the amorpha-4,11-diene production in engineered S. cerevisiae.


Assuntos
Proteínas de Bactérias/metabolismo , Saccharomyces cerevisiae/genética , Sesquiterpenos/metabolismo , Hemoglobinas Truncadas/metabolismo , Proteínas de Bactérias/genética , Sequência de Bases , Western Blotting , Primers do DNA , Dados de Sequência Molecular , Plasmídeos , Sesquiterpenos Policíclicos , Reação em Cadeia da Polimerase , Homologia de Sequência do Ácido Nucleico , Hemoglobinas Truncadas/genética
16.
Environ Sci Pollut Res Int ; 29(50): 76066-76077, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35665458

RESUMO

Groundwater level fluctuation is a common natural phenomenon that causes alternate changes in oxygen, moisture, and biogeochemical processes in sediments. Microbes are sensitive to these environmental changes. Therefore, a specific microbial community is proposed to form in the groundwater fluctuation zone (GFZ). The vertical distributions of microbial abundance, diversity, and functional microbes and genes in sediment profiles were investigated, focusing on the GFZ, using high-throughput 16S rRNA gene sequencing, qPCR, and the Functional Annotation of Prokaryotic Taxa (FAPROTAX) approach. The relationships between chemical variables and microbial community structure were investigated by redundancy analysis (RDA). Results showed that the microbial abundance and microbial community richness and diversity were higher in the sediments of the GFZ. The nitrate reducers prefer to stay just below the groundwater level in the GFZ. The predominant microbes in the GFZ functioned as nitrifiers and Fe-oxidizers. The specific community in the GFZ is mainly related to NO3- and Fe(III) in the sediment. Consequently, the biochemical processes nitrification and Fe- and Mn-oxidation sequentially happen above the nitrate-reduction zone near the groundwater level in the GFZ. These results provide new knowledge in the biogeochemistry cycle of the GFZ and its disturbance on the vertical distribution and transport of biogenic elements and contaminants.


Assuntos
Água Subterrânea , Microbiota , Compostos Férricos , Água Subterrânea/química , Nitratos , Oxigênio , RNA Ribossômico 16S/genética
17.
Bioresour Technol ; 347: 126692, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35017089

RESUMO

The synchronous nitrogen elimination and phosphorus (P) recovery can be realized by the novel one-stage partial nitritation/anammox (PN/A)-hydroxyapatite (HAP) crystallization (PN/A-HAP) process, which seems promising in actual application. This research firstly conducted the startup of the PN/A-HAP process based on reconciling biomass and mineral to cultivate the novel sludge with the strategy of alternating enhancement of biomass accumulation and mineral formation. Within three months, the nitrogen removal rate of 1.1 kg/m3/d and the P removal efficiency of 54.2% were achieved. The biomass reached to 3.7 g/L and the average particle size of sludge granules was about 260 µm. The microbial analysis indicated that in sludge the ammonium-oxidizing bacteria (AOB) mainly belonged to the genus Nitrosomonas, and the anammox bacteria mainly the genus Kuenenia. The main mineral in sludge was identified as HAP. This startup strategy is guidable for the application of one-stage PN/A-HAP process in actual wastewater treatment.


Assuntos
Compostos de Amônio , Esgotos , Oxidação Anaeróbia da Amônia , Biomassa , Reatores Biológicos , Desnitrificação , Durapatita , Nitrogênio , Oxirredução , Águas Residuárias
18.
Water Res ; 217: 118437, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35447572

RESUMO

Biofilm carriers can avoid microorganism washout while maintaining a high amount of biomass, but are also associated with a long biofilm formation period and biofilm aging. A single stage partial nitritation/anammox process (single stage PN/A) reactor was setup to study the biofilm growth characterization and treatment performance under an NLR of 0.53 to 0.90 gN/L/d over one year. Biofilm growth was divided into three stages: the formation stage, maturation stage and aging stage. The initial biofilm was observed at day 84. A nitrogen removal efficiency of 83.4% was achieved at an NLR of 0.90 gN/L/d during the mature biofilm stage. Starvation, nitrogen gas accumulation and hydroxyapatite formation resulted in biofilm aging. After mechanical stirring treatment, biofilm reactivation was achieved by biofilm re-formation within one month. There is clear potential for phosphorus recovery, as indicated by the 5.24% - 6.29% phosphorus content in the biofilm (similar to the 5%-7% phosphorus content in enhanced biological phosphate removal sludge). The AnAOB genera abundance in the biofilm maintained at a high level of 18.25%-32.31%, while the abundance of AnAOB increased from the initial 4.10% to 13.78% after mechanical stirring treatment in the suspended sludge ensured biofilm reactivation. The results of this study clearly show that mechanical stirring treatment can be used to achieve the biofilm reactivation as the biofilm fills with the hollow cylindrical carrier. This study has potential as a useful reference for the realization of the wide application of the biofilm single stage PN/A process in the future.


Assuntos
Compostos de Amônio , Esgotos , Oxidação Anaeróbia da Amônia , Biofilmes , Reatores Biológicos , Desnitrificação , Nitrogênio , Oxirredução , Fósforo , Águas Residuárias
19.
Front Immunol ; 13: 806825, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35250977

RESUMO

Porphyromonas gingivalis is a Gram-negative pathogenic bacterium associated with chronic periodontitis. The development of a chimeric peptide-based vaccine targeting this pathogen could be highly beneficial in preventing oral bone loss as well as other severe gum diseases. We applied a computational framework to design a multi-epitope-based vaccine candidate against P. gingivalis. The vaccine comprises epitopes from subunit proteins prioritized from the P. gingivalis reference strain (P. gingivalis ATCC 33277) using several reported vaccine properties. Protein-based subunit vaccines were prioritized through genomics techniques. Epitope prediction was performed using immunoinformatic servers and tools. Molecular modeling approaches were used to build a putative three-dimensional structure of the vaccine to understand its interactions with host immune cells through biophysical techniques such as molecular docking simulation studies and binding free energy methods. Genome subtraction identified 18 vaccine targets: six outer-membrane, nine cytoplasmic membrane-, one periplasmic, and two extracellular proteins. These proteins passed different vaccine checks required for the successful development of a vaccine candidate. The shortlisted proteins were subjected to immunoinformatic analysis to map B-cell derived T-cell epitopes, and antigenic, water-soluble, non-toxic, and good binders of DRB1*0101 were selected. The epitopes were then modeled into a multi-epitope peptide vaccine construct (linked epitopes plus adjuvant) to enhance immunogenicity and effectively engage both innate and adaptive immunity. Further, the molecular docking approach was used to determine the binding conformation of the vaccine to TLR2 innate immune receptor. Molecular dynamics simulations and binding free energy calculations of the vaccine-TLR2 complex were performed to highlight key intermolecular binding energies. Findings of this study will be useful for vaccine developers to design an effective vaccine for chronic periodontitis pathogens, specifically P. gingivalis.


Assuntos
Vacinas Bacterianas , Infecções por Bacteroidaceae , Porphyromonas gingivalis , Infecções por Bacteroidaceae/prevenção & controle , Periodontite Crônica/prevenção & controle , Biologia Computacional , Epitopos de Linfócito T , Humanos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Porphyromonas gingivalis/imunologia , Receptor 2 Toll-Like , Vacinas de Subunidades Antigênicas
20.
J Microbiol ; 60(9): 960-967, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35835960

RESUMO

In protein biotechnology, large soluble fusion partners are widely utilized for increased yield and solubility of recombinant proteins. However, the production of additional large fusion partners poses an additional burden to the host, leading to a decreased protein yield. In this study, we identified two highly disordered short peptides that were able to increase the solubility of an artificially engineered aggregation-prone protein, GFP-GFIL4, from 0.6% to 61% (D3-DP00592) and 46% (D4-DP01038) selected from DisProt database. For further confirmation, the peptides were applied to two insoluble E. coli proteins (YagA and YdiU). The peptides also enhanced solubility from 52% to 90% (YagA) and from 27% to 93% (YdiU). Their ability to solubilize recombinant proteins was comparable with strong solubilizing tags, maltose-binding protein (40 kDa) and TrxA (12 kDa), but much smaller (< 7 kDa) in size. For practical application, the two peptides were fused with a restriction enzyme, I-SceI, and they increased I-SceI solubility from 24% up to 75%. The highly disordered peptides did not affect the activity of I-SceI while I-SceI fused with MBP or TrxA displayed no restriction activity. Despite the small size, the highly disordered peptides were able to solubilize recombinant proteins as efficiently as conventional fusion tags and did not interfere with the function of recombinant proteins. Consequently, the identified two highly disordered peptides would have practical utility in protein biotechnology and industry.


Assuntos
Proteínas de Escherichia coli , Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas Ligantes de Maltose/genética , Proteínas Ligantes de Maltose/metabolismo , Peptídeos/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Solubilidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA