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1.
J Agric Food Chem ; 67(39): 10921-10929, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31496242

RESUMO

Free amino residues react with α-dicarbonyl compounds (DCs) contributing to the formation of advanced glycation end products (AGEs). Phenolic compounds can scavenge DCs, thus controlling the dietary carbonyl load. This study showed that high-molecular weight cocoa melanoidins (HMW-COM), HMW bread melanoidins (HMW-BM), and especially HMW coffee melanoidins (HMW-CM) are effective DC scavengers. HMW-CM (1 mg/mL) scavenged more than 40% DCs within 2 h under simulated physiological conditions, suggesting some physiological relevance. Partial acid hydrolysis of HMW-CM decreased the dicarbonyl trapping capacity, demonstrating that the ability to react with glyoxal, methylglyoxal (MGO), and diacetyl was mainly because of polyphenols bound to macromolecules. Caffeic acid (CA) and 3-caffeoylquinic acid showed a DC-scavenging kinetic profile similar to that of HMW-CM, while mass spectrometry data confirmed that hydroxyalkylation and aromatic substitution reactions led to the formation of a stable adduct between CA and MGO. These findings corroborated the idea that antioxidant-rich indigestible materials could limit carbonyl stress and AGE formation across the gastrointestinal tract.


Assuntos
Pão/análise , Cacau/química , Café/química , Diacetil/química , Depuradores de Radicais Livres/química , Extratos Vegetais/química , Polímeros/química , Cacau/metabolismo , Café/metabolismo , Diacetil/metabolismo , Depuradores de Radicais Livres/metabolismo , Trato Gastrointestinal/metabolismo , Glioxal/química , Humanos , Modelos Biológicos , Extratos Vegetais/metabolismo , Polímeros/metabolismo , Aldeído Pirúvico/química , Aldeído Pirúvico/metabolismo
2.
Eur J Histochem ; 63(3)2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31455073

RESUMO

RNA interference is a powerful approach to understand gene function both for therapeutic and experimental purposes. Since the lack of knowledge in the gene silencing of various hepatic cell lines, this work was aimed to compare two transfection agents, the liposome-based Lipofectamine™ RNAiMAX and the HepG2-specific, polymer-based GenMute™, in two cellular models of human hepatoma, HepG2 and Huh7.5. In the first part, we assessed transfection efficiency of a fluorescent Cy3-labeled negative control siRNA by cell imaging analysis; we found that cells treated with GenMute present a higher uptake of the fluorescent negative control siRNA when compared to Lipofectamine RNAiMAX-transfected cells, both in HepG2 and in Huh7.5 cells. In the second part, we evaluated GAPDH silencing with the two transfection reagents by RT-PCR similar GAPDH mRNA expression after each transfection treatment. Finally, we measured cell viability by the MTT assay, observing that cells transfected with GenMute have higher viability with respect to Lipofectamine RNAiMAX-administered cells. These results suggest that GenMute reagent might be considered the most suitable transfection agent for hepatic gene silencing.


Assuntos
Técnicas de Transferência de Genes , Lipídeos/química , Polímeros/química , RNA Interferente Pequeno/genética , Transfecção/métodos , Sequência de Bases , Carbocianinas/química , Carbocianinas/metabolismo , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Inativação Gênica , Gliceraldeído-3-Fosfato Desidrogenases/genética , Humanos , Metabolismo dos Lipídeos , Lipídeos/toxicidade , Lipossomos/química , Lipossomos/metabolismo , Lipossomos/toxicidade , Neoplasias Hepáticas/genética , Polímeros/metabolismo , Polímeros/toxicidade , Interferência de RNA
3.
Bioresour Technol ; 291: 121873, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377506

RESUMO

Cholinium-glycinate ([Ch][Gly]) and cholinium-alanate ([Ch][Ala]) were investigated on the pretreatment of mulberry stem (MS). It resulted in an increase of glucose from 14% to more than 74% compared to the untreated sample. Pretreatment by reused [Ch][Gly] showed good performance for delignification of >60%, and improved structural polysaccharide digestion. Each fractional component has high potential for lignin purification, and succinic acid fermentation. The extracted lignin with [Ch][Gly] showed >90% purity with good qualities of aromatic unit as confirmed by FT-IR and 1H NMR spectra. The carbohydrate rich material was employed for succinic acid fermentation with the highest yield of succinic acid more than 0.89 gsuccinic acid/gglucose. After purification, poly(butylene) succinate (PBS) was synthesized, and was characterized in comparison to commercial PBS.


Assuntos
Butileno Glicóis/metabolismo , Fermentação , Morus/metabolismo , Polímeros/metabolismo , Ácido Succínico/metabolismo , Aminoácidos/metabolismo , Glucose/metabolismo , Líquidos Iônicos/química , Lignina/química
4.
Bioresour Technol ; 291: 121821, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31352167

RESUMO

The aim of this work was to study ammonium-limited fed-batch conditions in heterotrophic C. vulgaris shake flask cultivations. Therefore, an innovative polymer-based ammonium release technique (polymer beads) was developed. Using these beads in shake flasks, C. vulgaris cultivations resulted in simultaneous growth and lipid accumulation. Lipid productivity was increased by 43% compared to batch cultivations. Furthermore, by online monitoring of the metabolic activity (RAMOS technique), unlimited growth and depletion of nutrients could be identified. A previously unknown sulfur limitation was detected in the applied Bold's Basal Medium. Combining the ammonium release beads with the RAMOS technique proved to be an efficient method for microalgae process development.


Assuntos
Compostos de Amônio/metabolismo , Chlorella vulgaris/metabolismo , Lipídeos/biossíntese , Microalgas/metabolismo , Polímeros/metabolismo
5.
Food Chem ; 299: 125120, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31288162

RESUMO

Although coffee beans have been widely studied, application of coffee flower (CF) has not been previously investigated. Here, we evaluated the use of CF for the production of bioactive compounds, melanoidins, and bio-sugars through the green process. Pressurized hot water extraction was found to be the most appropriate method for extracting bioactive compounds from CF, which contain high values of total phenolic content and have antioxidant properties. Caffeine and trigonelline were the main compounds in CF with yields of 1070.8 mg and 1092.8 mg/100 g dry weight (DW), respectively. Melanoidins were also identified and quantified in the CF extracts that is approximately 30.2% were efficiently recovered in the initial extracts of CF. Bio-sugar was also obtained from cellulase and pectinase at a 92.8% conversion rate. The aim of this study is to promote a novel approach using high amounts of CFs in the production of functional healthy foods and beverages.


Assuntos
Coffea/química , Flores/química , Compostos Fitoquímicos/metabolismo , Polímeros/metabolismo , Açúcares/metabolismo , Alcaloides/análise , Antioxidantes/análise , Cafeína/análise , Carboidratos/análise , Fenóis/análise
6.
Microb Cell Fact ; 18(1): 101, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31159886

RESUMO

BACKGROUND: Many fermented foods and beverages are produced through the action of complex microbial communities. Synthetic biology approaches offer the ability to genetically engineer these communities to improve the properties of these fermented foods. Soy sauce is a fermented condiment with a vast global market. Engineering members of the microbial communities responsible for soy sauce fermentation may therefore lead to the development of improved products. One important property is the colour of soy sauce, with recent evidence pointing to a consumer preference for more lightly-coloured soy sauce products for particular dishes. RESULTS: Here we show that a bacterial member of the natural soy sauce fermentation microbial community, Bacillus, can be engineered to reduce the 'browning' reaction during soy sauce production. We show that two approaches result in 'de-browning': engineered consumption of xylose, an important precursor in the browning reaction, and engineered degradation of melanoidins, the major brown pigments in soy sauce. Lastly, we show that these two strategies work synergistically using co-cultures to result in enhanced de-browning. CONCLUSIONS: Our results demonstrate the potential of using synthetic biology and metabolic engineering methods for fine-tuning the process of soy sauce fermentation and indeed for many other natural food and beverage fermentations for improved products.


Assuntos
Bacillus subtilis/metabolismo , Fermentação , Engenharia Metabólica/métodos , Polímeros/metabolismo , Alimentos de Soja , Soja/microbiologia , Xilose/metabolismo , Bacillus subtilis/genética , Técnicas de Cocultura , Microbiologia Industrial , Microbiota , Biologia Sintética , Xilose/genética
7.
J Biochem ; 166(3): 205-212, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31251348

RESUMO

Signal enhancing systems have been introduced to enable detection of cell surface antigens by flow cytometry. Cell surface antigens are important targets that describe the function and lineage of cells. Although flow cytometry is an effective tool for analysing cell surface antigens, this technique has poor sensitivity, which prohibits the detection of many important antigens on cell membranes. Thus, signal amplification is essential for developing practical tools for evaluating cell surface antigens by flow cytometry. Using a bright fluorophore or fluorescent polymer incorporated into antibodies is a straightforward strategy to improve flow cytometry sensitivity but may affect the functional characteristics of the labelled antibody. In contrast, enzymatic signal amplification is a more practical and efficient strategy to improve sensitivity that should not affect antibody activity. Although enzymatic signal amplification still has a number of drawbacks, this approach is a promising strategy to analyse cell surface antigens.


Assuntos
Antígenos de Superfície/análise , Citometria de Fluxo , Anticorpos/química , Anticorpos/imunologia , Anticorpos/metabolismo , Antígenos de Superfície/imunologia , Antígenos de Superfície/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Humanos , Polímeros/química , Polímeros/metabolismo
8.
Planta ; 250(1): 163-171, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30953149

RESUMO

MAIN CONCLUSION: Glucomannan was more strongly oriented, in line with the orientation of cellulose, than the xylan in both compression wood and normal wood of Chinese fir. Lignin in compression wood was somewhat more oriented in the direction of the cellulose microfibrils than in normal wood. The structural organization in compression wood (CW) is quite different from that in normal wood (NW). To shed more light on the structural organization of the polymers in plant cell walls, Fourier Transform Infrared (FTIR) microscopy in transmission mode has been used to compare the S2-dominated mean orientation of wood polymers in CW with that in NW from Chinese fir (Cunninghamia lanceolata). Polarized FTIR measurements revealed that in both CW and NW samples, glucomannan and xylan showed a parallel orientation with respect to the cellulose microfibrils. In both wood samples, the glucomannan showed a much greater degree of orientation than the xylan, indicating that the glucomannan has established a stronger interaction with cellulose than xylan. For the lignin, the absorption peak also indicated an orientation along the direction of the cellulose microfibrils, but this orientation was more pronounced in CW than in NW, indicating that the lignin is affected by the orientation of the cellulose microfibrils more strongly in CW than it is in NW.


Assuntos
Cunninghamia/ultraestrutura , Polímeros/metabolismo , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Celulose/metabolismo , Cunninghamia/metabolismo , Lignina/metabolismo , Mananas/metabolismo , Microfibrilas , Espectroscopia de Infravermelho com Transformada de Fourier , Madeira/metabolismo , Madeira/ultraestrutura , Xilanos/metabolismo
9.
Fungal Biol ; 123(4): 318-329, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30928040

RESUMO

In lichen symbiosis, polyol transfer from green algae is important for acquiring the fungal carbon source. However, the existence of polyol transporter genes and their correlation with lichenization remain unclear. Here, we report candidate polyol transporter genes selected from the genome of the lichen-forming fungus (LFF) Ramalina conduplicans. A phylogenetic analysis using characterized polyol and monosaccharide transporter proteins and hypothetical polyol transporter proteins of R. conduplicans and various ascomycetous fungi suggested that the characterized yeast' polyol transporters form multiple clades with the polyol transporter-like proteins selected from the diverse ascomycetous taxa. Thus, polyol transporter genes are widely conserved among Ascomycota, regardless of lichen-forming status. In addition, the phylogenetic clusters suggested that LFFs belonging to Lecanoromycetes have duplicated proteins in each cluster. Consequently, the number of sequences similar to characterized yeast' polyol transporters were evaluated using the genomes of 472 species or strains of Ascomycota. Among these, LFFs belonging to Lecanoromycetes had greater numbers of deduced polyol transporter proteins. Thus, various polyol transporters are conserved in Ascomycota and polyol transporter genes appear to have expanded during the evolution of Lecanoromycetes.


Assuntos
Ascomicetos/enzimologia , Ascomicetos/metabolismo , Líquens/microbiologia , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Polímeros/metabolismo , Ascomicetos/genética , Sequência Conservada , Filogenia , Homologia de Sequência
10.
Science ; 364(6436)2019 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-30975858

RESUMO

Plants and animals recognize conserved flagellin fragments as a signature of bacterial invasion. These immunogenic elicitor peptides are embedded in the flagellin polymer and require hydrolytic release before they can activate cell surface receptors. Although much of flagellin signaling is understood, little is known about the release of immunogenic fragments. We discovered that plant-secreted ß-galactosidase 1 (BGAL1) of Nicotiana benthamiana promotes hydrolytic elicitor release and acts in immunity against pathogenic Pseudomonas syringae strains only when they carry a terminal modified viosamine (mVio) in the flagellin O-glycan. In counter defense, P. syringae pathovars evade host immunity by using BGAL1-resistant O-glycans or by producing a BGAL1 inhibitor. Polymorphic glycans on flagella are common to plant and animal pathogenic bacteria and represent an important determinant of host immunity to bacterial pathogens.


Assuntos
Flagelina/imunologia , Flagelina/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Polímeros/metabolismo , Pseudomonas syringae/imunologia , Tabaco/enzimologia , Tabaco/microbiologia , beta-Galactosidase/metabolismo , Glicosilação , Hidrólise , Polissacarídeos/química , Polissacarídeos/metabolismo , Pseudomonas syringae/patogenicidade , Tabaco/genética , Tabaco/imunologia , beta-Galactosidase/genética
11.
Ecotoxicol Environ Saf ; 176: 211-218, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-30933895

RESUMO

Artemia cysts have a huge economic importance for the aquaculture sector due to the fact that they are used as live feed for larviculture. Microplastics (MPs) are common and emergent pollutants in the aquatic environments, with unknown and potential long-term effects on planktonic species such as Artemia spp. When used as live feed, Artemia could transfer contaminants to fish along the food chain, with possible adverse effects on human health through their consumption. This study aims to assess the uptake of different concentrations of spherical polymer microparticles (FRM) (1-5 µm diameter) and their associated chronic effects on feeding, growth, mortality, and reproductive success from juvenile to adult stage of brine shrimp Artemia franciscana. Individuals were exposed for 44 days to 0.4, 0.8 and 1.6 mg.L-1 of FRM. No significant detrimental effects on growth, ingestion and mortality rates of A. franciscana were observed in all tested conditions. However, reproductive success was strongly affected by the increase of MP concentrations. The results of the present study showed that A. franciscana juveniles and adults were able to survive different experimental MP concentrations, but their reproductive success and progeny were significantly impacted by exposure to FRM particles.


Assuntos
Artemia/efeitos dos fármacos , Polímeros/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Aquicultura , Artemia/metabolismo , Relação Dose-Resposta a Droga , Ingestão de Alimentos , Cadeia Alimentar , Tamanho da Partícula , Polímeros/metabolismo , Reprodução/efeitos dos fármacos , Poluentes Químicos da Água/metabolismo
12.
Biomater Sci ; 7(5): 1888-1897, 2019 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-30843539

RESUMO

Inefficient cytosolic delivery has limited the development of many promising biomacromolecular drugs, a long-standing challenge that has prompted extensive development of drug carriers that facilitate endosomal escape. Although many such carriers have shown considerable promise for cytosolic delivery of a diversity of therapeutics, the rupture or destabilization of endo/lysosomal membranes has also been associated with activation of the inflammasome with attendant risk of inflammation and toxicity. In this study, we investigated relationships between pH-dependent membrane destabilization, cytosolic drug delivery, and inflammasome activation using a series of well-defined poly[(ethylene glycol)-block-[(2-(dimethylamino)ethyl methacrylate)-co-(butyl methacrylate)] copolymers of variable second block composition and pH-responsive properties. We found that polymers that demonstrated the most potent membrane-destabilizing activity at early endosomal pH values in an erythrocyte hemolysis assay were most efficient at delivery of siRNA, yet tended to be associated with the least amount of NOD-like related protein 3 (NLRP3) inflammasome activation. By contrast, polymers that displayed minimal hemolysis activity and poor siRNA knockdown, and instead mediated lysosomal rupture likely due to a proton sponge mechanism, strongly induced NLPR3 inflammasome activation in a caspase- and cathepsin-dependent manner. Collectively, these findings reinforce the importance of early endosomal escape in minimizing inflammasome activation and also demonstrate the ability to tune the degree inflammasome activation via control of polymer structure with potential implications for design of vaccine adjuvants and immunotherapeutics.


Assuntos
Citosol/metabolismo , Portadores de Fármacos/química , Endossomos/metabolismo , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Polímeros/química , Linhagem Celular , Membrana Celular/metabolismo , Portadores de Fármacos/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Polímeros/metabolismo
13.
Biointerphases ; 14(2): 021003, 2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30925841

RESUMO

The force required to detach a single fibroblast cell in contact with the conducting polymer, polypyrrole doped with dodecylbenzene, was quantified using the Atomic Force Microscope-based technique, Single Cell Force Spectroscopy. The de-adhesion force for a single cell was 0.64 ± 0.03 nN and predominately due to unbinding of α5ß1 integrin complexes with surface adsorbed fibronectin, as confirmed by blocking experiments using antibodies. Monophasic pulsed stimulation (50 µs pulse duration) superimposed on either an applied oxidation (+500) or reduction (-500 mV) constant voltage caused a significant decrease in the de-adhesion force by 30%-45% to values ranging from 0.34 to 0.43 nN (±0.02 nN). The electrical stimulation caused a reduction in the molecular-level jump and plateau interactions, while an opposing increase in nonspecific interactions was observed during the cell de-adhesion process. Due to the monophasic pulsed stimulation, there is an apparent change or weakening of the cell membrane properties, which is suggested to play a role in reducing the cell de-adhesion. Based on this study, pulsed stimulation with optimized threshold parameters represents a possible approach to tune cell interactions and adhesion on conducting polymers.


Assuntos
Derivados de Benzeno/metabolismo , Adesão Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Fibroblastos/fisiologia , Microscopia de Força Atômica/métodos , Polímeros/metabolismo , Pirróis/metabolismo , Análise de Célula Única/métodos , Animais , Linhagem Celular , Fibronectinas/metabolismo , Integrina alfa5beta1/metabolismo , Camundongos
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 215: 158-167, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30831393

RESUMO

The interaction of flavonoids extracted from yellow onion skins with whey proteins isolate was studied using fluorescence spectroscopy and simulation methods from the perspectives of microencapsulation. The fluorescence spectroscopy revealed a static quenching mechanism and the involvement of van der Waals and H bonding in complexes formation. The in silico methods suggested that the heat treatment of the major whey proteins affected the binding pockets and therefore the affinity for the main flavonoids. The interaction surface decreased and the interaction energy increased, suggesting lower binding strength. Further, the yellow onion skins extract was successfully encapsulated in whey proteins isolate and different combinations of polymers, including chitosan, maltodextrin and pectin by freeze drying. The resulted powder showed a total flavonoid content of 5.84 ±â€¯0.23 mg quercetin equivalents/g DW in whey protein-chitosan combination and 104.97 ±â€¯5.02 mg quercetin equivalents/g DW in whey protein-maltodextrin-pectin combinations, with antioxidant activity of 175.93 ±â€¯1.50 mM mM Trolox/g DW and 269.20 ±â€¯3.59 mM Trolox/g DW, respectively. The confocal microscopy indicated that the flavonoids aggregated inside the matrix formed between the whey proteins and various polymers and irregular and compact clusters. Therefore, a comprehensive approach involving the extraction of flavonoids from underutilized food by-products, such as yellow onion skins, evaluation of binding mechanisms with whey proteins, whereas tailoring their functional benefit through microencapsulation in order to obtain active ingredients are reported.


Assuntos
Composição de Medicamentos/métodos , Flavonoides/química , Cebolas/química , Proteínas do Soro do Leite/química , Flavonoides/metabolismo , Modelos Moleculares , Polímeros/química , Polímeros/metabolismo , Ligação Proteica , Espectrometria de Fluorescência , Proteínas do Soro do Leite/metabolismo
15.
Carbohydr Polym ; 212: 215-221, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30832850

RESUMO

DrzBC and DrzBS (10-23 DNAzyme) could block the expression of HBV e- and s- gene respectively. But the application of 10-23 DNAzyme was limited owing to the lack of appropriate delivery vehicles. Chitosan oligosaccharide-SS-Octadecylamine (CSSO), a redox-responsive nano-sized polymeric carrier, could self-aggregate and bind with DNA by electrostatic interaction at proper mass ratio. Compared with the traditional commercial carrier Lipo2000, CSSO exhibited lower cytotoxicity, efficient cellular uptake by targeting cells, and rapidly DNA released in cytoplasm after escaping from endosomes. Including the same DNA concentration, Lipo2000/(DrzBC or DrzBS) showed maximum inhibitory rate on HBeAg (47.29 ±â€¯1.86%) and HBsAg (33.58 ±â€¯0.72%) secretion after 48 h incubation, and then both decreased. In contrast, HBeAg secretion inhibition by CSSO/DrzBC and HBsAg secretion inhibition by CSSO/DrzBS were up to 73.86 ±â€¯1.77% and 67.80 ±â€¯2.51% at 48 h, and further increased to 83.83 ±â€¯2.34% and 76.79 ±â€¯2.18% at 72 h, respectively. CSSO is a promising redox-responsive polymeric carrier for efficient anti-Hepatitis B Virus gene therapy.


Assuntos
Aminas/administração & dosagem , Quitosana/administração & dosagem , Terapia Genética/métodos , Vírus da Hepatite B/efeitos dos fármacos , Oligossacarídeos/administração & dosagem , Polímeros/administração & dosagem , Aminas/metabolismo , Quitosana/metabolismo , DNA Viral/efeitos dos fármacos , DNA Viral/genética , DNA Viral/metabolismo , Relação Dose-Resposta a Droga , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/metabolismo , Células Hep G2 , Vírus da Hepatite B/genética , Vírus da Hepatite B/metabolismo , Humanos , Oligossacarídeos/metabolismo , Oxirredução/efeitos dos fármacos , Polímeros/metabolismo
16.
Int J Mol Sci ; 20(5)2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-30871103

RESUMO

Interaction of proteins with charged macromolecules is involved in many processes in cells. Firstly, there are many naturally occurred charged polymers such as DNA and RNA, polyphosphates, sulfated glycosaminoglycans, etc., as well as pronouncedly charged proteins such as histones or actin. Electrostatic interactions are also important for "generic" proteins, which are not generally considered as polyanions or polycations. Finally, protein behavior can be altered due to post-translational modifications such as phosphorylation, sulfation, and glycation, which change a local charge of the protein region. Herein we review molecular modeling for the investigation of such interactions, from model polyanions and polycations to unfolded proteins. We will show that electrostatic interactions are ubiquitous, and molecular dynamics simulations provide an outstanding opportunity to look inside binding and reveal the contribution of electrostatic interactions. Since a molecular dynamics simulation is only a model, we will comprehensively consider its relationship with the experimental data.


Assuntos
Substâncias Macromoleculares/metabolismo , Polímeros/metabolismo , Proteínas/metabolismo , Animais , Humanos , Simulação de Dinâmica Molecular , Poliaminas/metabolismo , Ligação Proteica/fisiologia , Processamento de Proteína Pós-Traducional/fisiologia , Eletricidade Estática
17.
Eur Biophys J ; 48(4): 317-327, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30927020

RESUMO

A microscopic transport model of a polymer translocating through a nuclear pore complex (NPC) is presented based on self-consistent field theory (SCFT), with the NPC and its nucleoporins mimicked by a hairy channel. Multiple cell environment effects (electrolyte effect, excluded volume effect, NPC drag effect, and hydrophobic effect) are all considered in this hairy channel model. The influence of various parameters (polymer chain length, length of NPC, strength of hydrophobic effect, and excluded volume effect) on translocation time is studied through theoretical analysis and numerical calculation. Numerical simulation results show that an area of low nucleoporin number density exists in the NPC, which facilitates the translocation of the polymer. The results also show that the translocation time curves with increasing NPC length and polymer charge number are concave. In addition, there are critical values for NPC length and polymer charge number for which the translocation time has a minimal value. The translocation time decreases with the increasing strength of the hydrophobic effect and excluded volume effect.


Assuntos
Modelos Biológicos , Poro Nuclear/metabolismo , Polímeros/metabolismo , Citoplasma/metabolismo , Difusão , Interações Hidrofóbicas e Hidrofílicas , Termodinâmica
18.
J Biosci Bioeng ; 128(2): 191-197, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30799088

RESUMO

Novel lactate (LA)-based polymers containing medium-chain-length 3-hydroxyalkanoates (MCL-3HA) were produced in fadR-deficient Escherichia coli strains from glucose as the sole carbon source. The genes encoding LA and 3-hydroxybutyrate (3HB) monomers supplying enzymes [propionyl-CoA transferase (PCT), d-lactate dehydrogenase (D-LDH), ß-ketothiolase (PhaA), and NADPH-dependent acetoacetyl-CoA reductase (PhaB)], MCL-3HA monomers supplying enzymes [(R)-3-hydroxyacyl-ACP thioesterase (PhaG) and (R)-3-hydroxyacyl (3HA)-CoA ligase] via fatty acid biosynthesis pathway, and modified polyhydroxyalkanoate (PHA) synthase [PhaC1(STQK)] of Pseudomonas sp. 61-3 were introduced into E. coli LS5218. This resulted in the synthesis of a novel LA-based copolymer, P(LA-co-3HB-co-3HA). 1H-nuclear magnetic resonance (NMR) analysis revealed the composition of P(LA-co-3HB-co-3HA) to be 19.7 mol% LA (C3), 74.9 mol% 3HB (C4), and 5.4 mol% MCL-3HA units of C8 and C10. Furthermore, the recombinant E. coli CAG18497 strain carrying these genes, excluding the phaAB genes, accumulated P(92.0% LA-co-3HA) with a novel monomer composition containing C3, C8, C10, and C12. 13C-NMR analysis showed the existence of LA-3HA sequence in the polymer. The solvent cast film of P(92.0% LA-co-3HA) exhibited transparency similar to poly(lactic acid).


Assuntos
DNA Recombinante/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Glucose/metabolismo , Ácido Láctico/química , Polímeros/química , Polímeros/metabolismo , Aciltransferases/genética , Aciltransferases/metabolismo , Oxirredutases do Álcool/genética , Oxirredutases do Álcool/metabolismo , Pseudomonas/genética
19.
Bioresour Technol ; 280: 165-172, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30771571

RESUMO

The aim of this work was to study the ability of commercial immobilized hydrolases in the decolorization of molasses wastewater. Commercial immobilized keratinase obtained the highest decolorization yield (86.6-91.1%) among all of commercial immobilized enzymes tested. Immobilized keratinase had the potential to replace immobilized oxidoreductase to decolorize molasses wastewater. Keratinase from Meiothermus taiwanensis WR-220 (KMT) immobilized on modified bagasse cellulose obtained a decolorization yield of 84.7-90.2%. It removed 60.2-65.6% of colorants and 61.4-69.8% of chemical oxygen demand (COD) for 5 days continuously. Notably, the treatment cost was less than 0.15 dollar per ton. Immobilized KMT-wt had similar performance with commercial immobilized keratinase in bleaching molasses wastewater. Importantly, it was more economic. Finally, the results confirmed that additional reaction catalyzing the unsaturated bonds to destroy the conjugated system by keratinase, weakening the chromogenic group of melanoidins. Accordingly, this work is meaningful to the industrial decolorization of molasses wastewater.


Assuntos
Deinococcus/enzimologia , Melaço , Peptídeo Hidrolases/metabolismo , Polímeros/metabolismo , Biocatálise , Análise da Demanda Biológica de Oxigênio , Cor , Enzimas Imobilizadas/metabolismo , Águas Residuárias
20.
Bioresour Technol ; 279: 132-139, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30716605

RESUMO

This study reports the result of sodium citrate induced exopolymer extraction on the photocatalytic thin film (TiO2) pretreatment efficiency of waste activated sludge (WAS). TiO2 is immobilized through DC spluttering method followed by annealing process. The exopolymer removal of 94.2% by sodium citrate (0.05 g/g SS) promotes better disintegration. This TiO2 thin film efficiently extricate the intracellular components of exopolymer extracted sludge at 50 min increasing the solubilization to 19.33%. As a result, the exopolymer extracted sludge shows high methane generation (0.24 gCOD/gCOD) than the other (pretreated sludge without exopolymer removal - 0.12 gCOD/gCOD and raw sludge without treatment - 0.075 gCOD/gCOD). The methane generated in sodium citrate induced TiO2 thin film pretreated sludge is 398.99 kWh. In cost analysis, it gives net cost of -57.46 USD/ton of sludge. In addition, the proposed method also accounts 51.3% of solid reduction.


Assuntos
Biocombustíveis , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Anaerobiose , Catálise , Metano/biossíntese , Processos Fotoquímicos , Polímeros/metabolismo , Esgotos
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