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1.
Carbohydr Polym ; 227: 115346, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590873

RESUMO

This study reports excellent supercapacitor performance of hierarchical composite porous carbon (HPC) materials successfully fabricated by one-step carbonization and activation process derived from polysaccharides carboxymethyl cellulose, bacterial cellulose, and citric acid. The resultant HPC displayed unique porous nanosheet morphology with high specific surface area (2490 m2 g-1) and rich oxygen content (7.3%). The developed structures with macropores, mesopore walls, micropores, and high oxygen content led to excellent electrochemical performance for electrode of electric double-layer capacitors (EDLCs). In a three-electrode system, the HPC electrode showed a high specific capacitance of 350 F g-1, good rate performance, and excellent cycling stability. The energy density of supercapacitor based on HPC was comparable to or higher than that of commercially supercapacitors. More importantly, two series-wound devices were easy to light light-emitting diode (LED, 3.0 V). These results suggest that the current material is a promising candidate for low-cost and eco-friendly energy storage devices.


Assuntos
Celulose/química , Ácido Cítrico/química , Capacitância Elétrica , Polissacarídeos Bacterianos/química , Carbono/química , Fontes de Energia Elétrica , Eletrodos , Porosidade
2.
Carbohydr Polym ; 227: 115369, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590875

RESUMO

The isolation, screening, and identification of multi-metal resistant (Cd, Cu, Pb, and Zn) bacteria from polluted coastal sediment samples were performed. In this study, the isolates S2-2 and S3-2 had higher multi-metal resistance and were identified as Pseudomonas pachastrellae KMS2-2 and Bacillus cereus KMS3-1, respectively. One-variable-at-a time approach suggested that optimum conditions for exopolysaccharides (EPS) production were pH 7.0, incubation time 120 h, 5 g/L sucrose, and 10 g/L yeast extract. Further, optimization by central composite design revealed that the optimum concentrations of sucrose and yeast extract for higher EPS production (8.9 g/L) were 5 g/L, and 30 g/L, respectively. Heteropolysaccharide nature of EPS determined by FTIR, TLC, and HPLC analysis, consist of mannose, rhamnose, glucose, and xylose. In addition, EPS showed strong emulsifying and flocculation activity. Results suggested the potential EPS-producing multi-metal resistant Bacillus cereus KMS3-1 could be used in biotechnological and industrial application, especially metal removal.


Assuntos
Bacillus cereus/metabolismo , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/metabolismo , Bacillus cereus/efeitos dos fármacos , Bacillus cereus/isolamento & purificação , Emulsões , Floculação , Sedimentos Geológicos/microbiologia , Metais Pesados/farmacologia , Pseudomonas/isolamento & purificação
3.
Carbohydr Polym ; 227: 115323, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590841

RESUMO

Bacterial nanocellulose (BNC) has many advantages over plant cellulose, which make it widely used in many fields, especially in the food industry. In this study, three strains including BCA263, BCC529, and P1 were selected for characteristics analysis of BNCs under static and agitated culture conditions. The BNCs produced under static culture condition were in the shape of uniform membrane, while BNCs produced under agitated culture were in form of small agglomerates and fragments. BCA263 and BCC529 strains were more suitable for static culture, while P1 strain was more suitable for agitated culture. BNCs produced under static culture condition exhibited higher crystallinity, stronger tensile strength, denser network structure, higher temperature resistance and good flame retardancy; while BNCs produced under agitated culture condition exhibited larger porous and lower crystallinity. Furthermore, BNCs produced under agitated culture condition were more suitable as a stabilizer of coffee milk beverage.


Assuntos
Acetobacteraceae/metabolismo , Celulose/metabolismo , Nanopartículas/metabolismo , Polissacarídeos Bacterianos/metabolismo , Animais , Técnicas Bacteriológicas , Celulose/química , Café , Conservação de Alimentos , Microscopia Eletrônica de Varredura , Leite , Nanopartículas/química , Nanopartículas/ultraestrutura , Polissacarídeos Bacterianos/química
4.
Carbohydr Polym ; 227: 115347, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590845

RESUMO

Viscosupplementation, i.e. intra-articular injection of hyaluronic acid derivatives, is considered as the most effective treatment for patients with mild to moderate osteoarthritis. Even if hyaluronic acid is still considered as the gold standard, research is now focusing on the development of new products with enhanced injectability and yet reasonable viscoelastic behavior for OA treatment. A Gellan Gum (GG) hydrogel was synthesized and coated with crosslinked polyvinyl alcohol (PVA) to protect the polysaccharide from degradation during sterilization and improve its performance for the foreseen application. Thermal analyses indicated that mixed hydrogel showed a higher degree of structuring than the bare polysaccharide core without losing its swelling properties, thanks to the hydrophylicity of both coating and cross-linking agent. The PVA coating increased elastic and viscous moduli of the polysaccharide core conferring it a higher resistance to shear and compression and better thixotropic properties. Despite the double crosslinking, hydrogel was injectable. Cytocompatibility towards chondrocytes was verified.


Assuntos
Hidrogéis/química , Polissacarídeos Bacterianos/química , Álcool de Polivinil/química , Animais , Proliferação de Células , Sobrevivência Celular , Condrócitos , Módulo de Elasticidade , Humanos , Camundongos , Células NIH 3T3 , Osteoartrite/tratamento farmacológico , Viscosidade
5.
Chemistry ; 25(71): 16277-16287, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31506992

RESUMO

Group B Streptococcus serotypes Ia and Ib capsular polysaccharides are key targets for vaccine development. In spite of their immunospecifity these polysaccharides share high structural similarity. Both are composed of the same monosaccharide residues and differ only in the connection of the Neu5Acα2-3Gal side chain to the GlcNAc unit, which is a ß1-4 linkage in serotype Ia and a ß1-3 linkage in serotype Ib. The development of efficient regioselective routes for GlcNAcß1-3[Glcß1-4]Gal synthons is described, which give access to different group B Streptococcus (GBS) Ia and Ib repeating unit frameshifts. These glycans were used to probe the conformation and molecular dynamics of the two polysaccharides, highlighting the different presentation of the protruding Neu5Acα2-3Gal moieties on the polysaccharide backbones and a higher flexibility of Ib polymer relative to Ia, which can impact epitope exposure.


Assuntos
Cápsulas Bacterianas/química , Polissacarídeos Bacterianos/síntese química , Streptococcus/metabolismo , Cápsulas Bacterianas/metabolismo , Glucosamina/química , Glicosilação , Conformação Molecular , Polissacarídeos Bacterianos/química , Sorogrupo , Estereoisomerismo
6.
J Appl Microbiol ; 127(6): 1716-1726, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31517429

RESUMO

AIMS: To purify and characterize an exopolysaccharide (EPS) from an Agrobacterium strain ZCC3656 with high EPS-secreting performance and investigate its anti-inflammatory activity using lipopolysaccharide (LPS)-induced macrophage cells in an acute liver injury mouse model. METHODS AND RESULTS: Twelve rhizobial strains were compared for EPS fermentation production in modified M9 salts supplemented with mannitol or sucrose as the sole carbon source. Agrobacterium sp. ZCC3656 exhibited the highest EPS yield (21·1 g l-1 ) and was characterized for EPS production by carbon source utilization, time course fermentation and serial subcultivation assays. The EPS, designated Riclin, was purified by deproteinization using the Sevag method. The combined results of gel permeation chromatography, monosaccharide composition, methylation analysis and nuclear magnetic resonance analyses indicated that Riclin is a succinoglycan-like polysaccharide comprised of glucose, galactose, succinate and pyruvate at a ratio of 7·8. : 1·0 : 0·9 : 1·1 and has an molecular weight of approximately 2·5 × 106  Da. Riclin inhibited TNF-α, IL-1ß and IL-6 expression in LPS-stimulated RAW 264.7 macrophage cells in a dose-dependent manner. In addition, Riclin pretreatment increased the survival rate of D-Gal/LPS treated mice, inhibited serum ALT and AST activities and reduced the production of the inflammatory mediators TNF-α, IL-1ß and IL-6. CONCLUSIONS: Agrobacterium sp. ZCC3656 is a highly stable EPS-producing strain. The EPS Riclin from ZCC3656 is a succinoglycan-type polysaccharide that is noncytotoxic and exhibits remarkable anti-inflammatory effects in vivo and in vitro. SIGNIFICANCE AND IMPACT OF THE STUDY: Succinoglycans are well known for good rheological properties and their physiological interactions with plants. However, their potential activity towards mammals has received little attention. Our study revealed that the succinoglycan Riclin exhibited excellent anti-inflammatory activities and could be considered as a promising reagent in anti-inflammatory treatment.


Assuntos
Agrobacterium/química , Anti-Inflamatórios/farmacologia , Macrófagos/efeitos dos fármacos , Polissacarídeos Bacterianos/farmacologia , Agrobacterium/metabolismo , Animais , Anti-Inflamatórios/química , Citocinas/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Masculino , Camundongos , Polissacarídeos Bacterianos/química , Células RAW 264.7
7.
J Agric Food Chem ; 67(42): 11627-11637, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31553177

RESUMO

Liver diseases alter the gut microbiota, but several lactic acid bacteria can reduce the degree of liver damage. The present study investigated whether Lactobacillus buchneri TCP016 reduces the degree of liver damage by modifying the gut microbiota via its exopolysaccharides (EPSs). First, it was illustrated that the main EPS (EPS016; molecular weight = 8.509 × 104 Da) comprised rhamnose, xylose, glucosamine, glucuronic acid, galactose, galacturonic acid, glucose, and mannose in molar ratios of 9.2:3.9:3.8:2.8:2.1:2.0:1.6:1.0. Our data showed that EPS016 alleviated the increase in plasma and hepatic enzyme and cytokine levels, increased superoxide dismutase and glutathione activity, and alleviated bacterial translocation to the liver and mesenteric lymph nodes in vivo. Furthermore, EPS016 ameliorated intestinal mucosal injury and gut flora dysbiosis, thereby decreasing the enrichment of Helicobacteraceae, Lachnospiraceae, and Enterobacteriaceae and increasing the abundance of Lactobacillus, Rikenellaceae, Bacteroidaceae, Bacteroidales_S24-7_group, and Prevotellaceae. These findings indicated that EPS016 inhibits lipopolysaccharides/d-galactosamine-induced liver injury and improves the modification of the gut microbiota.


Assuntos
Microbioma Gastrointestinal/efeitos dos fármacos , Lactobacillus/química , Hepatopatias/tratamento farmacológico , Polissacarídeos Bacterianos/administração & dosagem , Animais , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Feminino , Galactosamina/efeitos adversos , Humanos , Lactobacillus/metabolismo , Lipopolissacarídeos/efeitos adversos , Hepatopatias/etiologia , Hepatopatias/microbiologia , Camundongos Endogâmicos BALB C , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/metabolismo
8.
Mater Sci Eng C Mater Biol Appl ; 104: 109983, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499997

RESUMO

We report the development of halloysite nanotubes (HNTs)/carboxylated-cellulose nanocrystals (cCNCs) - reinforced and ionically-crosslinked k-carrageenan (k-CG)/xanthan gum (XG) hydrogels. In this study, cCNCs were extracted from microcrystalline cellulose using ammonium persulfate and exhibit 'spindle-like' nanocrystals with approximate diameter of 15-30 nm and length of 30-120 nm. The freeze-dried hydrogels showed highly porous microstructure with good pore-interconnectivity. Further, tunable swelling ratio and in vitro degradation rate of hydrogels under physiological condition (pH 7.4 PBS, 37 °C) were observed. In wet or dry states, the dynamic mechanical analysis of kCXGHN20cCN20 hydrogel showed significantly improved compressive strengths (at 50% strain: 8.1 ±â€¯1.35 kPa or 81.33 ±â€¯1.66 kPa, whereas at 70% strain: 11.84 ±â€¯0.61 kPa or 120.7 ±â€¯1.16 kPa) when reinforced with HNTs (20 wt%)/cCNCs (20 wt%), respectively. The stiffness values are reported at different compressive strains. All hydrogels showed excellent attachment and proliferation of human skin fibroblasts (CCD-986Sk) cells on hydrogels for 7 and 14 days of culture periods. The results showed that these hydrogels may have potential application in soft tissue engineering.


Assuntos
Celulose/química , Argila/química , Hidrogéis/química , Nanopartículas/química , Nanotubos/química , Polissacarídeos/química , Linhagem Celular , Força Compressiva/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Humanos , Polissacarídeos Bacterianos/química , Porosidade , Pele/efeitos dos fármacos , Engenharia Tecidual/métodos
9.
Int J Mol Sci ; 20(18)2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31500233

RESUMO

Helicobacter pylori colonises the human stomach and has tropism for the gastric mucin, MUC5AC. The majority of organisms live in the adherent mucus layer within their preferred location, close to the epithelial surface where the pH is near neutral. Trefoil factor 1 (TFF1) is a small trefoil protein co-expressed with the gastric mucin MUC5AC in surface foveolar cells and co-secreted with MUC5AC into gastric mucus. Helicobacter pylori binds with greater avidity to TFF1 dimer, which is present in gastric mucus, than to TFF1 monomer. Binding of H. pylori to TFF1 is mediated by the core oligosaccharide subunit of H. pylori lipopolysaccharide at pH 5.0-6.0. Treatment of H. pylori lipopolysaccharide with mannosidase or glucosidase inhibits its interaction with TFF1. Both TFF1 and H. pylori have a propensity for binding to mucins with terminal non-reducing α- or ß-linked N-acetyl-d-glucosamine or α-(2,3) linked sialic acid or Gal-3-SO42-. These findings are strong evidence that TFF1 has carbohydrate-binding properties that may involve a conserved patch of aromatic hydrophobic residues on the surface of its trefoil domain. The pH-dependent lectin properties of TFF1 may serve to locate H. pylori deep in the gastric mucus layer close to the epithelium rather than at the epithelial surface. This restricted localisation could limit the interaction of H. pylori with epithelial cells and the subsequent host signalling events that promote inflammation.


Assuntos
Helicobacter pylori/fisiologia , Lipopolissacarídeos/metabolismo , Estômago/microbiologia , Fator Trefoil-1/metabolismo , Mucinas Gástricas/metabolismo , Glucosidases/farmacologia , Helicobacter pylori/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Lipopolissacarídeos/química , Manosidases/farmacologia , Mucina-5AC/metabolismo , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/metabolismo , Ligação Proteica/efeitos dos fármacos , Multimerização Proteica , Fator Trefoil-1/química , Tropismo
10.
Microbiol Res ; 229: 126324, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31491671

RESUMO

Through extracellular electron transfer (EET), bacteria are capable of transforming different insoluble materials of geochemical interest into energy-rich molecules for their growth. For this process, bacteria have been depending directly or indirectly on molecules synthesized within the cells or by various synthetics as mediators. Herein, we studied the in-situ change in electrochemistry and supporting components for EET in the extracellular polysaccharide (EPS) producing biofilm of thermophilic Geobacillus sp. The CV and DPV resultsrevealed that the intact biofilm of bacteria was not able to generate any potential at 25 °C /- ≤50 °C. However, at 55 °C (optimal condition), the potential occurred drastically after the EPS production by bacteria. HPLC and MALDI-TOF results revealed that the presence of Flavins, which can able adsorbed to the electrodes from the cell surface. Moreover, the temperature-dependent EPS production and originally conceived ability of flavins to act as electron shuttles suggest that not much complexity in bacteria with minerals. Additionally, the electrochemical potential was severely affected upon removal of EPS/flavin moiety from the intact biofilm, revealed the necessity of EPS bound flavins in transferring the electrons across its thick cell walls. This paradigm shift to electrogenic nature of Geobacillus sp. biofilm will become evident in the adaptation of other microbes during mineral respiration in extreme environments.


Assuntos
Flavinas/metabolismo , Geobacillus/metabolismo , Polissacarídeos Bacterianos/metabolismo , Biofilmes , Transporte de Elétrons , Elétrons , Flavinas/química , Geobacillus/química , Geobacillus/genética , Polissacarídeos Bacterianos/química
11.
Biol Pharm Bull ; 42(9): 1545-1553, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31474714

RESUMO

The aim of the present study is to construct and characterize a novel three-dimensional culture system for mouse neurons using the functional polymer, FP001. Stereoscopically extended neurites were found in primary mouse cortical neurons cultured in the FP001-containing medium. Neurons cultured with FP001 were distributed throughout the medium of the observation range whereas neurons cultured without FP001 were distributed only on the bottom of the dish. These results demonstrated that neurons can be three-dimensionally cultured using the FP001-containing medium. The mRNA expression of the glutamatergic neuronal marker vesicular glutamate transporter 1 in neurons cultured in the FP001-containing medium were higher than that in neurons cultured in the FP001-free medium. Expression of the matured neuronal marker, microtubule-associated protein 2 (MAP2) a,b, and the synapse formation marker, Synapsin I, in neurons cultured with FP001 was also higher than that in neurons cultured without FP001. The expression pattern of MAP2a,b in neurons cultured with FP001, but not that in neurons cultured without FP001, was similar to that in the embryonic cerebral cortex. Exposure to glutamate significantly increased 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction activity in neurons cultured with FP001 compared to that in neurons cultured without FP001. These results suggested that glutamatergic neurotransmission in neurons three-dimensionally cultured in the FP001-containing medium may be upregulated compared to neurons two-dimensionally cultured in the FP001-free medium. Thus, neurons with the properties close to those in the embryonic brain could be obtained by three-dimensionally culturing neurons using FP001, compared to two-dimensional culture with a conventional adhesion method.


Assuntos
Técnicas de Cultura de Células/métodos , Córtex Cerebral/citologia , Meios de Cultura/química , Neurônios/citologia , Polissacarídeos Bacterianos/química , Animais , Córtex Cerebral/embriologia , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Proteínas Associadas aos Microtúbulos/metabolismo , Neuritos/metabolismo , Neurônios/metabolismo , Sinapsinas/metabolismo
12.
Environ Sci Pollut Res Int ; 26(29): 30087-30097, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31414394

RESUMO

Although the viscosity behavior of bacteria and extracellular polymeric substances (EPS) in flocculent activated sludge (FAS) and aerobic granular sludge (AGS) has been investigated, no studies have explored the role of viscosity in microbial attachment in pure culture. This study investigated the viscosity behavior of bacteria and EPS. The results showed that bacteria and their EPS exhibited non-Newtonian fluid and shear-thinning behavior. The viscosity of bacteria and EPS was 1.55-3.80 cP and 1.10-2.40 cP, respectively, while the attachment of bacteria (optical density at 600 nm) was 0.1426-3.1015. Bacteria with high attachment secreted EPS with a higher viscosity (2.40 cP), whereas those with weak attachment expressed EPS with a lower viscosity (1.10 cP). Viscosity and microbial attachment or extracellular polysaccharide (PS) content were significantly positively correlated. PS content was the source of bacterial viscosity, and ß-polysaccharide played a more important role in viscosity and microbial attachment than α-polysaccharide. Thus, viscosity plays a critical role in microbial attachment, and high viscosity and PS content result in high microbial attachment, which is beneficial to the granulation process of AGS.


Assuntos
Bactérias/química , Matriz Extracelular de Substâncias Poliméricas/química , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Aderência Bacteriana , Biofilmes/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Floculação , Polissacarídeos Bacterianos/química , Esgotos/química , Suspensões , Viscosidade
13.
Carbohydr Polym ; 223: 115062, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426967

RESUMO

Nata de coco was chemically modified to afford the bacterial cellulose hydrogels carrying terminal alkynes. The resultant hydrogels were then converted into hydrogels carrying lactosides or those carrying α-2,3-sialyllactosides by the Cu+-catalyzed alkyne-azide cyclization. The stable homo association of the hydrogels carrying lactosides was observed in an aqueous solution containing Ca2+, thereby demonstrating the Ca2+-mediated lactoside-lactoside interactions. Ca2+ also stabilized the hetero associations among the hydrogels carrying lactosides and those carrying α-2,3-sialyllactosides, thereby also demonstrating the Ca2+-induced interactions between the lactosides and the α-2,3-sialyllactosides. The sizes of these hydrogels were of the order of ca. 5 mm, and their associations could thus be readily monitored with the naked eye.


Assuntos
Celulose/química , Hidrogéis/química , Oligossacarídeos/química , Polissacarídeos Bacterianos/química , Alquinos/química , Azidas/química , Cálcio/química , Cocos/química , Cocos/microbiologia , Hidrogéis/síntese química , Magnésio/química , Lectinas de Plantas/química , Ricinus/química , Sódio/química
14.
Molecules ; 24(16)2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31434298

RESUMO

The main goal of this mini review is to summarise the most recent progress in the field of conjugated graft copolymers featuring conjugation across the main chain, across side chains or across both. The main approaches to the synthesis of conjugated graft copolymers are highlighted, and the various trends in the development of new copolymer materials and the intended directions of their applications are explored.


Assuntos
Técnicas Biossensoriais , Sistemas de Liberação de Medicamentos , Polímeros/química , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Técnicas de Química Sintética , Corrosão , Hidrogéis/química , Polissacarídeos Bacterianos/química , Pirróis/química , Eliminação de Resíduos Líquidos/métodos
15.
Int J Biol Macromol ; 138: 950-957, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31351957

RESUMO

Bacterial Cellulose (BC), a valuable biopolymer gaining importance over the past few decades due to its remarkable properties and applications. In this study, crude distillery effluent having a high COD value of 87,433 mg/L was used to produce Bacterial Cellulose under static fermentation by Komagataeibacter saccharivorans, a novel isolated bacterial strain. 1.24 g/L of cellulose production was noted after eight days along with 23.6% reduction in COD value. The BC pellicle was purified, lyophilized and stored. Further, the lyophilized BC pellicle was subjected to characterization techniques such as SEM, ATR-FTIR, XRD, NMR and TLC. Morphological analysis revealed that cellulose fibers were dense with higher porosity and an average fiber width of 60 nm. FTIR depicted similar functional groups as that of BC-HS medium. TLC of the biopolymer was performed to evaluate its purity. X-ray diffraction and 13C NMR studies gave more insights about the crystalline and the amorphous regions; the synthesized polymer exhibited 80.2% as crystallinity and crystallite size of 8.36. Hence, the present study demonstrates that distillery effluent waters could be effectively reused as production medium fulfilling two objectives namely one reducing COD and making the effluent safe for disposal and two to produce a value-added product.


Assuntos
Celulose/química , Nutrientes/química , Polissacarídeos Bacterianos/química , Celulose/isolamento & purificação , Celulose/ultraestrutura , Destilação , Nutrientes/isolamento & purificação , Polissacarídeos Bacterianos/isolamento & purificação , Polissacarídeos Bacterianos/ultraestrutura , Análise Espectral
16.
Int J Biol Macromol ; 138: 975-985, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31351958

RESUMO

Despite the advantages of bacterial cellulose (BC) over traditional cellulose, its low yield and little bioactivity makes a limitation to be used in an industrial scale. This paper was mainly dual aimed to increase the BC yield using a nanobioactive glass (NBG), and in situ synthesize BC/NBG bioactive nanocomposites by a novel and simple green method. Accordingly, the composites were prepared via in situ fermentation approach by incorporation of NBG particles into BC producing culture medium. The effect of NBG addition on the production process of cellulose, biocompatibility, bioactivity and antimicrobial activity were investigated. The results showed that NBG was enhanced and increased the BC yield and this has been achieved by maintaining these NBG on the pH value of the culture medium during the fermentation period. Moreover, it was effectively improved biocompatibility and antimicrobial properties of BC. This study evidenced that BC/NBG composite can be expected to be widely applied in biomedical industries such as bone regeneration and wound healing with the unique of being not harmful to humans.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Celulose/química , Vidro/química , Nanocompostos/química , Polissacarídeos Bacterianos/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Celulose/síntese química , Técnicas de Química Sintética , Química Verde , Humanos , Polissacarídeos Bacterianos/síntese química , Análise Espectral
17.
Eur J Pharm Biopharm ; 142: 498-505, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31330258

RESUMO

AIM: It was the aim of this study to assess in vitro methods for the characterization of mucoadhesive hydrogels for their potential to predict the residence time on human buccal mucosa. METHODS: Mixtures of hydrogels comprising hydroxyethyl cellulose (HEC), sodium carboxymethyl cellulose (CMC), xanthan gum (XTGM), hyaluronic acid sodium salt (HA), sodium alginate (ALG), carbopol (CP) as well as polycarbophil (PCP) and porcine mucus were analysed for relative rheological synergism. Furthermore, hydrogels were characterized for their texture and mechanical properties. For the assessment of mucoadhesive strength of formulations tensile studies were performed on porcine buccal mucosa. To facilitate a direct comparability of data the residence time of stained hydrogels was determined ex vivo on porcine buccal mucosa and in the oral cavity of volunteers. RESULTS: The extent of relative rheological synergism was in good agreement with data from in vivo residence time studies. Results of tensile studies were further effected by textural properties of hydrogels leading to a restricted correlation with data from the in vivo experiment. The resistance towards removal by artificial saliva flow ex vivo revealed the highest correlation to the in vivo experiment with increasing mucosal residence time in the rank order CP < HEC, HA, ALG, PCP < CMC < XTGM. CONCLUSIONS: This overview of measurement principles to predict the residence time of hydrogels for buccal application in humans may be a potent tool for the development of semisolid intraoral formulations.


Assuntos
Adesivos/química , Hidrogéis/química , Mucosa Bucal/metabolismo , Resinas Acrílicas/química , Administração Bucal , Adulto , Alginatos/química , Animais , Carboximetilcelulose Sódica/química , Celulose/análogos & derivados , Celulose/química , Correlação de Dados , Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos/métodos , Humanos , Ácido Hialurônico/química , Técnicas In Vitro/métodos , Boca , Polissacarídeos Bacterianos/química , Suínos , Adulto Jovem
18.
Carbohydr Res ; 483: 107745, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31349142

RESUMO

The K8 and K54 capsular polysaccharides were isolated from Acinetobacter baumannii BAL 097 and RCH52, respectively, and studied by sugar analysis, partial acid hydrolysis and selective solvolysis with CF3CO2H in the presence of 2-methyl-1-propanol, along with 1D and 2D 1H and 13C NMR spectroscopy. The following structures of related branched tetrasaccharide repeats (K units) of the polysaccharides were established: where Leg indicates 5,7-diamino-3,5,7,9-tetradeoxy-d-glycero-d-galacto-non-2-ulosonic (legionaminic) acid and R indicates (R)-3-hydroxybutanoyl or acetyl in the ratio ~2.5:1. The sequences of the KL8 and KL54 capsule gene clusters were closely related. The difference in the acyl group at O-7 on the sidechain legionaminic acid is due to differences in two genes in the legionaminic acid biosynthesis cluster. The wzy genes encoding the K unit polymerases are also different and make different linkages between the K units, allowing the first sugar of both K units to be identified as d-GlcpNAc. The shared Gtr20 glycosyltransferase, also encoded in KL63, forms the α-l-FucpNAc-(1 → 3)-d-GlcpNAc linkage, and Gtr19 was predicted to form α-d-GalpNAc-(1 → 3)-l-FucpNAc. Gtr18 from KL8 is 75% identical to Gtr108 from KL54 and both would link the Leg derivative to d-GalpNAc. Hence the genes present at the K locus were consistent with the composition and structures of the K8 and K54 capsular polysaccharides.


Assuntos
Acinetobacter baumannii/metabolismo , Polissacarídeos Bacterianos/química , Ácidos Siálicos/química , Acinetobacter baumannii/química , Cápsulas Bacterianas/química , Cápsulas Bacterianas/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Família Multigênica , Polissacarídeos Bacterianos/genética , Polissacarídeos Bacterianos/metabolismo
19.
Mater Sci Eng C Mater Biol Appl ; 103: 109770, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349525

RESUMO

In this work, the potential of titanium dioxide nanoparticles incorporated gellan gum (GG + TiO2-NPs) biofilm as wound dressing material was investigated. The GG + TiO2-NPs biofilm was prepared via evaporative casting technique and was characterized using FTIR, XRD, and SEM to study their physiochemical properties. The mechanical properties, swelling and water vapor transmission rate (WVTR) of biofilm was determined to comply with an ideal wound dressing material. In vitro and in vivo wound healing studies was carried out to evaluate the performance of GG + TiO2-NPs biofilm. In vitro wound healing was studied on 3 T3 mouse fibroblast cells for cell viability, cell proliferation, and scratch assay. The acridine orange/propidium iodide (AO/PI) staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to evaluate the viability of cell and cell proliferation. Cell migration assay was analyzed using Essen BioScience IncuCyteTM Zoom system. In vivo wound healing via open excision wounds model on Sprague Dawley rat was studied within 14 days. The FT-IR spectra of GG + TiO2-NPs biofilm show main bands assigned to OH stretching, OH deformation, and TiO stretching modes. XRD pattern of GG + TiO2-NPs biofilm suggesting that TiO2-NPs was successfully incorporated in biofilm and well distributed on the surface as proved by SEM analysis. The GG + TiO2-NPs biofilm shows higher mechanical strength and swelling (3.76 ±â€¯0.11 MPa and 1061 ±â€¯6%) as compared to pure GG film (3.32 ±â€¯0.08 Mpa and 902 ±â€¯6%), respectively. GG + TiO2-NPs biofilm shows good antibacterial properties as 9 ±â€¯0.25 mm and 11 ±â€¯0.06 mm exhibition zone was observed against Staphylococcus aureus and Escherichia coli bacteria, respectively. While no exhibition zone was obtained for pure GG biofilm. GG + TiO2-NPs biofilm also demonstrated better cell-to-cell interaction properties, as it's promoted cell proliferation and cell migration to accelerate open excision wound healing on Sprague Dawley rat. The wound treated with GG + TiO2-NPs biofilm was healed within 14 days, on the other hand, the wound is still can be seen when it was treated with GG. However, GG and GG + TiO2-NPs biofilm show no cytotoxicity effects on mouse fibroblast cells.


Assuntos
Antibacterianos , Bandagens , Escherichia coli/crescimento & desenvolvimento , Membranas Artificiais , Nanopartículas/química , Polissacarídeos Bacterianos , Staphylococcus aureus/crescimento & desenvolvimento , Titânio , Cicatrização/efeitos dos fármacos , Células 3T3 , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Camundongos , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/farmacologia , Ratos , Ratos Sprague-Dawley , Titânio/química , Titânio/farmacologia
20.
Soft Matter ; 15(30): 6171-6179, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31318005

RESUMO

In this work, we prepared locust bean gum (LBG)/gellan gum (Gg) double network (DN) hydrogels based on pH-sensitive borate-ester bonds in the LBG network and hydrogen-bond-associated double-helix bundles in the Gg network by using two novel natural polysaccharide polymers. The DN hydrogels with optimized Gg and borax concentrations exhibit good mechanical properties (the fracture tensile stress is almost three times that of the LBG single network hydrogel). Because of their unique thermo- and pH-sensitive DN structure, the LBG/Gg DN hydrogels also show excellent self-healing, thermo-processability, and pH-driven shape memory properties. Such novel DN hydrogels demonstrate strong potentiality in many challenging applications such as biomedicine, soft robotics and other fields.


Assuntos
Galactanos/química , Hidrogéis/química , Mananas/química , Gomas Vegetais/química , Polissacarídeos Bacterianos/química , Concentração de Íons de Hidrogênio , Fenômenos Mecânicos
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