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1.
J Nanobiotechnology ; 21(1): 161, 2023 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-37211593

RESUMO

BACKGROUND: Biofilm formation and its resistance to various antibiotics is a serious health problem in the treatment of wound infections. An ideal wound dressing should have characteristics such as protection of wound from microbial infection, suitable porosity (to absorb wound exudates), proper permeability (to maintain wound moisture), nontoxicity, and biocompatibility. Although silver nanoparticles (AgNPs) have been investigated as antimicrobial agents, their limitations in penetrating into the biofilm, affecting their efficiency, have consistently been an area for further research. RESULTS: Consequently, in this study, the optimal amounts of natural and synthetic polymers combination, along with AgNPs, accompanied by iron oxide nanoparticles (IONPs), were utilized to fabricate a smart bionanocomposite that meets all the requirements of an ideal wound dressing. Superparamagnetic IONPs (with the average size of 11.8 nm) were synthesized through co-precipitation method using oleic acid to improve their stability. It was found that the addition of IONPs to bionanocomposites had a synergistic effect on their antibacterial and antibiofilm properties. Cytotoxicity assay results showed that nanoparticles does not considerably affect eukaryotic cells compared to prokaryotic cells. Based on the images obtained by confocal laser scanning microscopy (CLSM), significant AgNPs release was observed when an external magnetic field (EMF) was applied to the bionanocomposites loaded with IONPs, which increased the antibacterial activity and inhibited the formation of biofilm significantly. CONCLUSION: These finding indicated that the nanocomposite recommended can have an efficient properties for the management of wounds through prevention and treatment of antibiotic-resistant biofilm.


Assuntos
Nanopartículas de Magnetita , Nanopartículas Metálicas , Nanocompostos , Cicatrização , Prata/farmacologia , Antibacterianos/farmacologia , Biofilmes , Testes de Sensibilidade Microbiana
2.
Appl Microbiol Biotechnol ; 106(3): 1113-1126, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35044498

RESUMO

Ammonia is a toxic byproduct of CHO cell metabolism, which inhibits cell growth, reduces cell viability, alters glycosylation, and decreases recombinant protein productivity. In an attempt to minimize the ammonium accumulation in cell culture media, different amino acids were added individually to the culture medium before the production phase to alleviate the negative effects of ammonium on cell culture performance. Among all the amino acids examined in this study, valine showed the most positive impact on CHO cell culture performance. When the cultured CHO cells were fed with 5 mM valine, EPO titer was increased by 25% compared to the control medium, and ammonium and lactate production were decreased by 23 and 26%, respectively, relative to the control culture. Moreover, the sialic acid content of the EPO protein in valine-fed culture was higher than in the control culture, most likely because of the lower ammonium concentration. Flux balance analysis (FBA) results demonstrated that the citric acid cycle was enriched by valine feeding. The measurement of TCA cycle activity supported this finding. The analysis revealed that there might be a link between promoting tricarboxylic acid (TCA) cycle metabolism in valine-fed culture and reduction in lactate and ammonia accumulation. Furthermore, in valine-fed culture, FBA outcomes showed that alanine was excreted into the medium as the primary mechanism for reducing ammonium concentration. It was predicted that the elevated TCA cycle metabolism was concurrent with an increment in recombinant protein production. Taken together, our data demonstrate that valine addition could be an effective strategy for mitigating the negative impacts of ammonium and enhancing glycoprotein production in both quality and quantity. KEY POINTS: • Valine feeding can mitigate the negative impacts of ammonia on CHO cell growth. • Valine addition assists the ammonia removal mechanism by enriching the TCA cycle. • Ammonia is removed from the media through alanine excretion in valine-fed culture.


Assuntos
Amônia , Carbono , Animais , Células CHO , Cricetinae , Cricetulus , Ácido Láctico , Valina
3.
Bioprocess Biosyst Eng ; 44(2): 317-328, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32955618

RESUMO

Schizophyllum commune is a wood-rotting filamentous fungus that secrets a homopolysaccharide called as schizophyllan. Schizophyllan has several applications such as enhanced oil recovery, pharmaceutical materials and an anti-cancer drug carrier. Biomass growth and schizophyllan production increase the viscosity of the cultivation medium, thus resulting in mass transfer limitation for the substrate. In this study, adding talc and aluminium oxide microparticles into the cultivation medium was studied to improve the fungal growth and morphology. The response surface methodology and one factor at a time were applied to find the effects of microparticles with different sizes and concentrations on the schizophyllan production. The optimum concentration and size of aluminium oxide microparticles were obtained as 20 g L-1 and < 30 µm, respectively. Aluminium oxide microparticles in shake flask culture caused to increase the schizophyllan production from 10 to 15 g L-1 and decrease the cultivation time from 10 to 7 days. The production yield also increased from 0.11 to 0.30 g of schizophyllan/g glucose. Bioreactor cultivation showed a twofold increase in schizophyllan production from 1.5 to 3 g L-1. The results of this study suggested a significant increase in the production of schizophyllan using a low-cost "microparticle-enhanced cultivation" without any further optimization of the culture medium.


Assuntos
Biomassa , Reatores Biológicos , Meios de Cultura , Schizophyllum/crescimento & desenvolvimento , Sizofirano/biossíntese , Óxido de Alumínio/química , Talco/química
4.
Bioprocess Biosyst Eng ; 44(10): 2075-2085, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34061248

RESUMO

Miniaturized bubble columns (MBCs) can provide mass transfer characteristics similar to stirred tank bioreactors. In this study, a new application was developed for MBCs to investigate the effect of feeding strategy and medium type on the fed-batch culture of recombinant E. coli. The results showed that the exponential feeding strategy and defined M9 medium were more suitable to achieve the high cell density culture (HCDC). The maximum obtained cell concentration in exponential feeding strategy in the defined medium without induction, was at OD600 of 169, while glucose concentration was maintained under 2 g/L. To the best of our knowledge, this cell concentration cannot be achieved in lab or pilot scale bubble columns. At the end of the process, adverse effect of the metabolic burden due to induction and mass transfer limitations decreased the obtained final cell concentration to OD600 of 116. Finally, a comparison of the results for fed-batch culture in the stirred tank bioreactor with those of the MBCs showed that their lower cell concentrations were due to the hydrodynamics limitations of MBCs. Yet, it was found that the MBCs are efficient tools in development of feeding strategies and evaluation of medium components for HCDC of recombinant E. coli.


Assuntos
Escherichia coli/metabolismo , Miniaturização , Recombinação Genética , Reatores Biológicos , Meios de Cultura , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Fermentação , Glucose/metabolismo , Proteínas Recombinantes/genética
5.
Curr Microbiol ; 77(8): 1756-1766, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32328749

RESUMO

Considering the economic importance of the probiotics, industrial production of their biomass became important. Cane molasses, as an industrial byproduct, was used in this study to design a medium for biomass overproduction of a functionally probiotic strain, designated as Lactobacillus plantarum strain RPR42. The results showed that strain RPR42 can be best grown anaerobically in 22.5% cane molasses solution. Also, the findings of the single variable at a time experiments and either factorial design indicated that the optimal growth of strain RPR42 can be observed when beef extract, casein hydrolysate, and yeast extract were added into the medium. The central composite design experiments suggested a medium which was designated as cane molasses medium (CMM). Eventually, this medium contained 21.9% cane molasses, 30.72 g/L of a combined mixture of nitrogenous compounds: 0.0754% of a 1:1:1 mixture of polysorbates 20, 60, and 80, and 18.53 gr/L of the combined minerals. Such an optimized cane molasses-based medium supported a significant biomass production since a considerably high cell density, 13.8 g/L/24 h of dry biomass, of the strain was produced. Hence, cane molasses can be regarded as a promising substrate for industrial production purposes.


Assuntos
Meios de Cultura/química , Microbiologia Industrial/métodos , Lactobacillus plantarum/crescimento & desenvolvimento , Melaço , Probióticos , Biomassa , Fermentação
6.
Drug Dev Ind Pharm ; 46(10): 1647-1655, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892656

RESUMO

OBJECTIVE: The combinational therapy is often considered as a desire in chemotherapy despite some limitations. This study aimed to encapsulate two natural-based drugs, curcumin (CUR), and piperine (PIP) into highly biocompatible albumin nanoparticles for anticancer applications. SIGNIFICANCE: A simultaneous exertion of CUR and PIP in a biocompatible drug delivery system with the minimum side effects and no limitations was achievable in this work for cancer treatment. METHODS: Curcumin and piperine co-loaded human serum albumin nanoparticles (CUR-PIP-HSA-NPs) were synthesized by the self-assembly method. The effectiveness of the codelivery system was evaluated physically, chemically, and pharmaceutically. Moreover, the anticancer activity of CUR-PIP-HSA-NPs was studied on MCF-7 cells by MTT assay. RESULTS: CUR-PIP-HSA-NPs showed appropriate stability with an average particle size of 154.7 ± 5.2 nm. Loading of drugs was demonstrated by Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC) analyses. The drug encapsulation efficiencies (DEEs) of CUR and PIP in NPs were 85.3% ± 1.46% and 81.7%, ± 1.67%, respectively. Furthermore, the drug loading efficiency (DLE) of CUR-PIP-HSA-NPs was 8.71% ± 0.24%. The circular dichroism (CD) examination of the NPs confirmed that the conformational structure of albumin remained unchanged during the synthesis. In addition, the cytotoxicity experiments demonstrated the high potential of CUR-PIP-HSA-NPs against breast cancer (MCF-7) cells in the presence of PIP as both bioenhancer and anticancer drug with the capability of suppressing the effect of multidrug resistance (MDR). CONCLUSIONS: The results suggest that CUR-PIP-HSA-NPs can be employed as a practical drug delivery system in cancer treatment with synergistic effects of both CUR and PIP.


Assuntos
Curcumina , Nanopartículas , Neoplasias , Alcaloides/química , Benzodioxóis/química , Curcumina/farmacologia , Sistemas de Liberação de Medicamentos , Humanos , Tamanho da Partícula , Piperidinas/química , Alcamidas Poli-Insaturadas/química , Albumina Sérica Humana/química , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Appl Microbiol Biotechnol ; 103(20): 8315-8326, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31418052

RESUMO

The cell culture medium is an intricate mixture of components which has a tremendous effect on cell growth and recombinant protein production. Regular cell culture medium includes various components, and the decision about which component should be included in the formulation and its optimum amount is an underlying issue in biotechnology industries. Applying conventional techniques to design an optimal medium for the production of a recombinant protein requires meticulous and immense research. Moreover, since the medium formulation for the production of one protein could not be the best choice for another protein, hence, the most suitable media should be determined for each recombinant cell line. Accordingly, medium formulation becomes a laborious, time-consuming, and costly process in biomanufacturing of recombinant protein, and finding alternative strategies for medium development seems to be crucial. In silico modeling is an attractive concept to be adapted for medium formulation due to its high potential to supersede laboratory examinations. By emerging the high-throughput datasets, scientists can disclose the knowledge about the effect of medium components on cell growth and metabolism, and via applying this information through systems biology approach, medium formulation optimization could be accomplished in silico with no need of significant amount of experimentation. This review demonstrates some of the applications of systems biology as a powerful tool for medium development and illustrates the effect of medium optimization with system-level analysis on the production of recombinant proteins in different host cells.


Assuntos
Bactérias/metabolismo , Biotecnologia/métodos , Meios de Cultura/química , Eucariotos/metabolismo , Proteínas Recombinantes/metabolismo , Biologia de Sistemas/métodos , Bactérias/crescimento & desenvolvimento , Eucariotos/crescimento & desenvolvimento
8.
Bioprocess Biosyst Eng ; 42(2): 257-266, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30362045

RESUMO

Miniaturized bubble columns (MBCs) have different hydrodynamics in comparison with the larger ones, but there is a lack of scientific data on MBCs. Hence, in this study, the effect of gas hold-up, flow regimes, bubble size distribution on volumetric oxygen mass transfer coefficient at different pore size spargers and gas flow rates in MBCs in the presence and absence of microorganisms were investigated. It was found that flow regime transition occurred around low gas flow rates of 1.18 and 0.85 cm/s for small (16-40 µm) and large (40-100 µm) pore size spargers, respectively. Gas hold-up and KLa in MBC with small size sparger were higher than those with larger one, with an increasing effect in the presence of microorganisms. A comparison revealed that the wall effect on the flow regime and gas hold-up in MBCs was greater than bench-scale bubble columns. The KLa values significantly increased up to tenfold using small pore size sparger. In the MBC and stirred tank bioreactors, the maximum obtained cell concentrations were OD600 of 41.5 and 43.0, respectively. Furthermore, it was shown that in MBCs, higher KLa and lower turbulency could be achieved at the end of bubbly flow regime.


Assuntos
Reatores Biológicos , Fermentação , Oxigênio/química , Ar , Desenho de Equipamento , Escherichia coli , Gases , Hidrodinâmica , Cinética , Viscosidade
9.
Bioinformatics ; 33(7): 1057-1063, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28065897

RESUMO

Motivation: Integration of different biological networks and data-types has been a major challenge in systems biology. The present study introduces the transcriptional regulated flux balance analysis (TRFBA) algorithm that integrates transcriptional regulatory and metabolic models using a set of expression data for various perturbations. Results: TRFBA considers the expression levels of genes as a new continuous variable and introduces two new linear constraints. The first constraint limits the rate of reaction(s) supported by a metabolic gene using a constant parameter (C) that converts the expression levels to the upper bounds of the reactions. Considering the concept of constraint-based modeling, the second set of constraints correlates the expression level of each target gene with that of its regulating genes. A set of constraints and binary variables was also added to prevent the second set of constraints from overlapping. TRFBA was implemented on Escherichia coli and Saccharomyces cerevisiae models to estimate growth rates under various environmental and genetic perturbations. The error sensitivity to the algorithm parameter was evaluated to find the best value of C. The results indicate a significant improvement in the quantitative prediction of growth in comparison with previously presented algorithms. The robustness of the algorithm to change in the expression data and the regulatory network was tested to evaluate the effect of noisy and incomplete data. Furthermore, the use of added constraints for perturbations without their gene expression profile demonstrates that these constraints can be applied to improve the growth prediction of FBA. Availability and Implementation: TRFBA is implemented in Matlab software and requires COBRA toolbox. Source code is freely available at http://sbme.modares.ac.ir . Contact: : motamedian@modares.ac.ir. Supplementary information: Supplementary data are available at Bioinformatics online.


Assuntos
Algoritmos , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Redes e Vias Metabólicas/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Perfilação da Expressão Gênica , Genoma , Modelos Biológicos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Software , Transcrição Gênica
10.
Bioprocess Biosyst Eng ; 41(7): 961-971, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29619548

RESUMO

The effects of all-trans retinoic acid (RA) and sodium butyrate (NaBu) on growth, viability and antibody production of two types of transfected Chinese hamster ovary cell lines (CHO-K1 and CHO-S) were investigated using a batch mode cell culture. By adding 0.5 mM NaBu in the CHO-K1 cell culture, the cell specific productivity (Qp) and antibody concentration increased by five- and threefold, respectively. The optimal concentration of RA was 100 nM which resulted in twofold increase in antibody production. In a combination model, RA applied at early growth phase of CHO-K1 cells followed by addition of NaBu with lowering culture temperature at the end of stationary phase resulted in two- and threefold increase in Qp and final antibody concentration, respectively. The latter strategy was also applied on suspended CHO-S cells with enhanced Qp and antibody concentration, but to a lesser extent than the CHO-K1 cells. In conclusion, our results demonstrate that the addition of RA and NaBu along with lowering the culture temperature can increase cell culture period as well as Qp and the final concentration of recombinant monoclonal antibody in both CHO-K1 and CHO-S cells without any significant change in binding affinity of the mAb.


Assuntos
Anticorpos Monoclonais/biossíntese , Ácido Butírico/farmacologia , Tretinoína/farmacologia , Animais , Anticorpos Monoclonais/genética , Células CHO , Técnicas de Cultura de Células , Cricetulus , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética
11.
Prep Biochem Biotechnol ; 48(4): 372-377, 2018 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-29509074

RESUMO

In this work, mathematical modeling of ethanol production in solid-state fermentation (SSF) has been done based on the variation in the dry weight of solid medium. This method was previously used for mathematical modeling of enzyme production; however, the model should be modified to predict the production of a volatile compound like ethanol. The experimental results of bioethanol production from the mixture of carob pods and wheat bran by Zymomonas mobilis in SSF were used for the model validation. Exponential and logistic kinetic models were used for modeling the growth of microorganism. In both cases, the model predictions matched well with the experimental results during the exponential growth phase, indicating the good ability of solid medium weight variation method for modeling a volatile product formation in solid-state fermentation. In addition, using logistic model, better predictions were obtained.


Assuntos
Biocombustíveis , Etanol/metabolismo , Zymomonas/metabolismo , Biocombustíveis/análise , Biocombustíveis/microbiologia , Simulação por Computador , Fibras na Dieta/metabolismo , Fermentação , Galactanos/metabolismo , Microbiologia Industrial/métodos , Cinética , Mananas/metabolismo , Modelos Biológicos , Gomas Vegetais/metabolismo , Zymomonas/crescimento & desenvolvimento
12.
Appl Microbiol Biotechnol ; 101(8): 3451-3462, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28062975

RESUMO

Biotrickling filters (BTFs) are often subjected to transient-state operation due to different variations in the operation of industrial-scale sources of pollution. In this research, performance of a laboratory-scale BTF packed with pall ring and pumice (1:1 v/v) and inoculated with Ralstonia eutropha was evaluated for the treatment of toluene vapor under various transient conditions. The experiments were performed at empty bed residence times (EBRTs) of 45 and 90 s and toluene inlet concentration in the range of 0.5-4 g m-3. The transient-state experiments consisted of a sudden increase in inlet gas concentration, sudden change of trickling liquid rate, intermittent loading for 10 h day-1, aeration without toluene loading during shutdown periods, and long-term starvation. The maximum elimination capacity (ECmax) was 280 g m-3 h-1 under continuous loading. The removal efficiency (RE) reached 90 % in intermittent loading experiments at toluene inlet concentration of 3 g m-3 in less than 1 h after loading initiation. RE dropped to 50 % due to 4.5-fold increase in the inlet loading rate (ILR) during shock load experiment. The system became completely active after 24 h, when the BTF was subjected to a long-term starvation period for 7 days. The results showed that aeration at non-toluene loading periods could improve the BTF performance under intermittent loading condition.


Assuntos
Filtração/métodos , Gases/análise , Tolueno/química , Poluentes Atmosféricos , Biodegradação Ambiental , Reatores Biológicos , Cupriavidus necator/metabolismo , Compostos Orgânicos Voláteis
13.
J Thromb Thrombolysis ; 43(2): 184-193, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27778144

RESUMO

Eptifibatide is an antiplatelet drug used for the treatment of thrombosis. However, as a result of its accumulation in non-targeted tissues and short half-life, it has a limited efficacy. In this study, RGD-modified nano-liposomes (RGD-MNL) were prepared as carriers for the targeted delivery of eptifibatide to activated platelets. The nano-liposomes were about 90 ± 10 nm in size, with an encapsulation efficiency of 37 ± 5 % and a good stability during 21 days, with a negligible change in the size of nanoliosomes. The in vitro cytotoxicity of nanoliposomes was examined using MTT assay. The results obtained from the ex vivo study showed that the antiplatelet activity of eptifibatide encapsulated nanoliposomes was higher in comparison with the free drug (81.63 vs. 46.17 % for RGD-MNL) and (66.67 vs. 46.17 % for UNL), and this increase was more significant for nanoliposomes targeted with RGD peptide (81.63 %; p < 0.05). The results indicated that RGD-MNL encapsulated eptifibatide had no significant cytotoxic effect on cells. In conclusion, the present nanoliposome formulation can be regarded as a new delivery system for protection and enhancement of the antiplatelet activity of eptifibatide.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Lipossomos/uso terapêutico , Peptídeos/administração & dosagem , Inibidores da Agregação Plaquetária/administração & dosagem , Plaquetas/citologia , Morte Celular/efeitos dos fármacos , Células Cultivadas , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Eptifibatida , Humanos , Lipossomos/química , Nanopartículas/química , Nanopartículas/uso terapêutico , Oligopeptídeos/química , Peptídeos/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia
14.
Biotechnol Bioeng ; 113(5): 961-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26480251

RESUMO

Pichia pastoris is used for commercial production of human therapeutic proteins, and genome-scale models of P. pastoris metabolism have been generated in the past to study the metabolism and associated protein production by this yeast. A major challenge with clinical usage of recombinant proteins produced by P. pastoris is the difference in N-glycosylation of proteins produced by humans and this yeast. However, through metabolic engineering, a P. pastoris strain capable of producing humanized N-glycosylated proteins was constructed. The current genome-scale models of P. pastoris do not address native nor humanized N-glycosylation, and we therefore developed ihGlycopastoris, an extension to the iLC915 model with both native and humanized N-glycosylation for recombinant protein production, but also an estimation of N-glycosylation of P. pastoris native proteins. This new model gives a better prediction of protein yield, demonstrates the effect of the different types of N-glycosylation of protein yield, and can be used to predict potential targets for strain improvement. The model represents a step towards a more complete description of protein production in P. pastoris, which is required for using these models to understand and optimize protein production processes.


Assuntos
Pichia/genética , Proteínas Recombinantes/genética , Glicosilação , Humanos , Microbiologia Industrial/métodos , Engenharia Metabólica/métodos , Pichia/metabolismo , Engenharia de Proteínas/métodos , Proteínas Recombinantes/metabolismo
15.
J Food Sci Technol ; 52(4): 1881-8, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25829569

RESUMO

Saffron (Crocus sativus L. stigma), the most valuable medicinal food product, belongs to the Iridaceae family which has been widely used as a coloring and flavoring agent. These properties are basically related to its crocins, picrocrocin and safranal contents which have all demonstrated health promoting properties. The present review article highlights the phytochemical constituents (phenolic and flavonoid compounds, degraded carotenoid compounds crocins and crocetin) that are important in antioxidant activity of saffron extracts. However, the synergistic effect of all the bioactive components presence in saffron gave a significant antioxidant activity similar to vegetables rich in carotenoids. Our study provides an updated overview focused on the antioxidant activity of saffron related to its bioactive compounds to design the different functional products in food, medicine and cosmetic industries.

16.
AAPS PharmSciTech ; 15(6): 1619-29, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25142823

RESUMO

Understanding the mechanism of aggregation of a therapeutic protein would not only ease the manufacturing processing but could also lead to a more stable finished product. Aggregation of recombinant interferon (IFNß-1b) was studied by heating, oxidizing, or seeding of unformulated monomeric solution. The formation of aggregates was monitored by dynamic light scattering (DLS) and UV spectroscopy. The autocatalytic monomer loss model was used to fit the data on aggregation rates. The influence of pre-nucleation on aggregation step was demonstrated by inducing the liquid samples containing a monomer form of folded IFNß-1b by heat and also an oxidizing agent. Results tend to suggest that the nucleus includes a single protein molecule which has been probably deformed. Seeding tests showed that aggregation of IFNß-1b was probably initiated when 1.0% (w/w) of monomers converted to nucleus form. Chemiluminescence spectroscopy analysis of the sample indicated the generation of 3.0 µM of hydrogen peroxide (H2O2) during nucleation stage of IFNß-1b aggregation. Arginine with a concentration of 200 mM was sufficient to suppress aggregation of IFNß-1b by decreasing the rate of pre-nucleation step. We proposed the formation of pre-nucleus structures prior to nucleation as the mechanism of aggregation of IFNß-1b. Furthermore, we have showed the positive anti-aggregation effect of arginine on pre-nucleation step.


Assuntos
Antivirais/química , Arginina/química , Excipientes/química , Interferon beta/química , Antivirais/farmacologia , Linhagem Celular Tumoral , Efeito Citopatogênico Viral/efeitos dos fármacos , Vírus da Encefalomiocardite/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/química , Interferon beta-1b , Interferon beta/farmacologia , Cinética , Luz , Modelos Químicos , Oxirredução , Agregados Proteicos , Dobramento de Proteína , Proteínas Recombinantes/química , Espalhamento de Radiação , Espectrofotometria Ultravioleta , Tecnologia Farmacêutica/métodos
17.
World J Microbiol Biotechnol ; 30(2): 693-704, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24068530

RESUMO

In the present study, the biosynthesis of silver nanoparticles (AgNPs) using Neurospora intermedia, as a new non-pathogenic fungus was investigated. For determination of biomass harvesting time, the effect of fungal incubation period on nanoparticle formation was investigated using UV-visible spectroscopy. Then, AgNPs were synthesized using both culture supernatant and cell-free filtrate of the fungus. Two different volume ratios (1:100 and 1:1) of the culture supernatant to the silver nitrate were employed for AgNP synthesis. In addition, cell-free filtrate and silver nitrate were mixed in presence and absence of light. Smallest average size and highest productivity were obtained when using equal volumes of the culture supernatant and silver nitrate solution as confirmed by UV-visible spectra of colloidal AgNPs. Comparing the UV-visible spectra revealed that using cell-free filtrate for AgNP synthesis resulted in the formation of particles with higher stability and monodispersity than using culture supernatant. The absence of light in cell-free filtrate mediated synthesis led to the formation of nanoparticles with the lowest rate and the highest monodispersity. The presence of elemental silver in all prepared samples was confirmed using EDX, while the crystalline nature of synthesized particles was verified by XRD. FTIR results showed the presence of functional groups which reduce Ag(+) and stabilize AgNPs. The presence of nitrate reductase was confirmed in the cell-free filtrate of the fungus suggesting the potential role of this enzyme in AgNP synthesis. Synthesized particles showed significant antibacterial activity against E. coli as confirmed by examining the growth curve of bacterial cells exposed to AgNPs.


Assuntos
Antibacterianos/metabolismo , Antibacterianos/farmacologia , Nanopartículas/metabolismo , Neurospora/metabolismo , Prata/metabolismo , Prata/farmacologia , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Espectrofotometria , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
18.
Int J Biol Macromol ; 259(Pt 2): 129287, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38211924

RESUMO

Probiotics have recently received significant attention due to their various benefits, such as the modulation of gut flora, reduction of blood sugar and insulin resistance, prevention and treatment of digestive disorders, and strengthening of the immune system. One of the major issues concerning probiotics is the maintenance of their viability in the presence of digestive conditions and extended shelf life during storage. To address this concern, numerous techniques have been explored to achieve success. Among these methods, the microencapsulation of probiotics has been proposed as the most effective way to overcome this challenge. The combination of nanomaterials with biopolymer coating is considered a novel approach to improve its viability and effective delivery. The use of polysaccharides and proteins-based bionanocomposites for microencapsulation of probiotics has emerged as an efficient and promising approach for maintaining cell viability and targeted delivery. This review article aims to investigate the use of different bionanocomposites in microencapsulation of probiotics and their effect on cell survival in long-term storage and harsh conditions in the gastrointestinal tract.


Assuntos
Probióticos , Viabilidade Microbiana , Polissacarídeos/farmacologia , Trato Gastrointestinal
19.
Biotechnol Lett ; 35(1): 67-73, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22996642

RESUMO

Magnetically-modified Sphingomonas sp. was prepared using covalent binding of magnetic nanoparticles on to the cell surface. The magnetic modified bacteria were immobilized in the fixed-bed bioreactors (FBR) by internal and external magnetic fields for the biodetoxification of a model organophosphate, parathion: 93 % of substrate (50 mg parathion/l) was hydrolyzed at 0.5 ml/min in internal magnetic field fixed-bed bioreactor. The deactivation rate constants (at 1 ml/min) were 0.97 × 10(-3), 1.24 × 10(-3) and 4.17 × 10(-3) h(-1) for immobilized bacteria in external and internal magnetic field fixed-bed bioreactor and FBR, respectively. The deactivation rate constant for immobilized magnetically modified bacteria in external magnetic field fixed-bed bioreactor (EMFFBR) was 77 % lower than that of immobilized cells by entrapping method on porous basalt beads in FBR at 1 ml/min. Immobilized magnetic modified bacteria exhibited maximum enzyme stability in EMFFBR.


Assuntos
Reatores Biológicos/microbiologia , Células Imobilizadas/enzimologia , Nanopartículas de Magnetita/química , Paration/farmacocinética , Sphingomonas/enzimologia , Arildialquilfosfatase/química , Arildialquilfosfatase/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Biodegradação Ambiental , Células Imobilizadas/metabolismo , Estabilidade Enzimática , Hidrólise , Sphingomonas/metabolismo
20.
Prep Biochem Biotechnol ; 43(5): 415-30, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23581778

RESUMO

Bioethanol production from carob pods has attracted many researchers due to its high sugar content. Both Zymomonas mobilis and Saccharomyces cerevisiae have been used previously for this purpose in submerged and solid-state fermentation. Since extraction of sugars from the carob pod particles is a costly process, solid-state and solid submerged fermentations, which do not require the sugar extraction step, may be economical processes for bioethanol production. The aim of this study is to evaluate the bioethanol production in solid submerged fermentation from carob pods. The maximum ethanol production of 0.42 g g(-1) initial sugar was obtained for Z. mobilis at 30°C, initial pH 5.3, and inoculum size of 5% v/v, 9 g carob powder per 50 mL of culture media, agitation rate 0 rpm, and fermentation time of 40 hr. The maximum ethanol production for S. cerevisiae was 0.40 g g(-1) initial sugar under the same condition. The results obtained in this research are comparable to those of Z. mobilis and S. cerevisiae performance in other culture mediums from various agricultural sources. Accordingly, solid submerged fermentation has a potential to be an economical process for bioethanol production from carob pods.


Assuntos
Biocombustíveis/análise , Etanol/metabolismo , Fermentação , Galactanos , Mananas , Gomas Vegetais , Saccharomyces cerevisiae/metabolismo , Zymomonas/metabolismo , Meios de Cultura/metabolismo , Frutose/metabolismo , Glucose/metabolismo , Sacarose/metabolismo
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