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1.
Biophys J ; 121(9): 1632-1642, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35390297

RESUMO

Cell viscoelastic properties are affected by the cell cycle, differentiation, and pathological processes such as malignant transformation. Therefore, evaluation of the mechanical properties of the cells proved to be an approach to obtaining information on the functional state of the cells. Most of the currently used methods for cell mechanophenotyping are limited by low robustness or the need for highly expert operation. In this paper, the system and method for viscoelasticity measurement using shear stress induction by fluid flow is described and tested. Quantitative phase imaging (QPI) is used for image acquisition because this technique enables one to quantify optical path length delays introduced by the sample, thus providing a label-free objective measure of morphology and dynamics. Viscosity and elasticity determination were refined using a new approach based on the linear system model and parametric deconvolution. The proposed method allows high-throughput measurements during live-cell experiments and even through a time lapse, whereby we demonstrated the possibility of simultaneous extraction of shear modulus, viscosity, cell morphology, and QPI-derived cell parameters such as circularity or cell mass. Additionally, the proposed method provides a simple approach to measure cell refractive index with the same setup, which is required for reliable cell height measurement with QPI, an essential parameter for viscoelasticity calculation. Reliability of the proposed viscoelasticity measurement system was tested in several experiments including cell types of different Young/shear modulus and treatment with cytochalasin D or docetaxel, and an agreement with atomic force microscopy was observed. The applicability of the proposed approach was also confirmed by a time-lapse experiment with cytochalasin D washout, whereby an increase of stiffness corresponded to actin repolymerization in time.


Assuntos
Neoplasias , Citocalasina D , Módulo de Elasticidade , Elasticidade , Reprodutibilidade dos Testes , Viscosidade
2.
Front Cell Neurosci ; 16: 830757, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35281293

RESUMO

The cellular pathology of schizophrenia and the potential of antipsychotics to target underlying neuronal dysfunctions are still largely unknown. We employed glutamatergic neurons derived from induced pluripotent stem cells (iPSC) obtained from schizophrenia patients with known histories of response to clozapine and healthy controls to decipher the mechanisms of action of clozapine, spanning from molecular (transcriptomic profiling) and cellular (electrophysiology) levels to observed clinical effects in living patients. Glutamatergic neurons derived from schizophrenia patients exhibited deficits in intrinsic electrophysiological properties, synaptic function and network activity. Deficits in K+ and Na+ currents, network behavior, and glutamatergic synaptic signaling were restored by clozapine treatment, but only in neurons from clozapine-responsive patients. Moreover, neurons from clozapine-responsive patients exhibited a reciprocal dysregulation of gene expression, particularly related to glutamatergic and downstream signaling, which was reversed by clozapine treatment. Only neurons from clozapine responders showed return to normal function and transcriptomic profile. Our results underscore the importance of K+ and Na+ channels and glutamatergic synaptic signaling in the pathogenesis of schizophrenia and demonstrate that clozapine might act by normalizing perturbances in this signaling pathway. To our knowledge this is the first study to demonstrate that schizophrenia iPSC-derived neurons exhibit a response phenotype correlated with clinical response to an antipsychotic. This opens a new avenue in the search for an effective treatment agent tailored to the needs of individual patients.

3.
J Biomol Struct Dyn ; 40(7): 3155-3169, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-33200680

RESUMO

SARS-CoV-2 cause fatal infection in 213 countries accounting for the death of millions of people globally. In the present study, phytochemicals from spices were assessed for their ability to interact with SARS-CoV-2 MPro. Structure based virtual screening was performed with 146 phytochemicals from spices using Autodock Vina. Phytochemicals with binding energy ≥ -8.0 kcal/mol were selected to understand their interaction with MPro. Virtual screening was further validated by performing molecular docking to generate favorable docked poses and the participation of important amino acid residues. Molecular dynamics simulation for the docked poses was performed to study thermodynamic properties of the protein, ligand and protein-ligand complexes. The finding shows that cinnamtannin B2 and cyanin showed favorable binding affinity values with SARS-CoV-2 MPro. The results are comparable in terms of docked poses, important amino acid participation and thermodynamic properties with the standard control drugs remdesivir, benazepril and hydroxychloroquine diphosphate. Prime MM-GBSA was employed for end-point binding energy calculation. Binding to domain I and II of MPro were mediated through the OH, SH, NH2 and non-polar side chain of amino acids. Cinnamtannin B2 and cyanin binds to MPro with many sub sites within the active site with RMSD and RMSF within 4 Å. The results computed using Prime MM-GBSA show that cinnamtannin B2 (-68.54940214 kcal/mol) and cyanin (-62.1902835 kcal/mol) have better binding affinity in comparison to hydroxychloroquine diphosphate (-54.00912412 kcal/mol) and benazepril (-53.70242369 kcal/mol). The results provide a basis for exploiting cinnamtannin B2 and cyanin as a starting point potential candidate for the development of drug against SARS-CoV-2.Communicated by Ramaswamy H. Sarma.


Assuntos
Tratamento Farmacológico da COVID-19 , Simulação de Dinâmica Molecular , Humanos , Simulação de Acoplamento Molecular , Compostos Fitoquímicos/química , Compostos Fitoquímicos/farmacologia , Inibidores de Proteases/química , SARS-CoV-2
4.
Biotechnol Adv ; 58: 107889, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-34929313

RESUMO

Solventogenic clostridia are not a strictly defined group within the genus Clostridium but its representatives share some common features, i.e. they are anaerobic, non-pathogenic, non-toxinogenic and endospore forming bacteria. Their main metabolite is typically 1-butanol but depending on species and culture conditions, they can form other metabolites such as acetone, isopropanol, ethanol, butyric, lactic and acetic acids, and hydrogen. Although these organisms were previously used for the industrial production of solvents, they later fell into disuse, being replaced by more efficient chemical production. A return to a more biological production of solvents therefore requires a thorough understanding of clostridial metabolism. Transcriptome analysis, which reflects the involvement of individual genes in all cellular processes within a population, at any given (sampling) moment, is a valuable tool for gaining a deeper insight into clostridial life. In this review, we describe techniques to study transcription, summarize the evolution of these techniques and compare methods for data processing and visualization of solventogenic clostridia, particularly the species Clostridium acetobutylicum and Clostridium beijerinckii. Individual approaches for evaluating transcriptomic data are compared and their contributions to advancements in the field are assessed. Moreover, utilization of transcriptomic data for reconstruction of computational clostridial metabolic models is considered and particular models are described. Transcriptional changes in glucose transport, central carbon metabolism, the sporulation cycle, butanol and butyrate stress responses, the influence of lignocellulose-derived inhibitors on growth and solvent production, and other respective topics, are addressed and common trends are highlighted.


Assuntos
Clostridium acetobutylicum , Clostridium beijerinckii , Butanóis/metabolismo , Clostridium/metabolismo , Clostridium acetobutylicum/genética , Clostridium acetobutylicum/metabolismo , Clostridium beijerinckii/genética , Clostridium beijerinckii/metabolismo , Fermentação , Solventes , Transcriptoma/genética
5.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 2741-2744, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34891817

RESUMO

This paper focuses on the analysis of image sequences acquired during fast photobleaching using a standard wide-field microscope. We show that the photobleaching rate estimated for each pixel is not constant for the whole field of view, but it provides a new spatially variant parametric image related to the cell structure and diffusion of fluorophores. We also provide an alternative way to estimate a pixel-wise photobleaching rate with significantly less computation time than exponential model fitting.Clinical Relevance- This method provides an additional way how fluorescence photobleaching might be used for increasing the image contrast.


Assuntos
Corantes Fluorescentes , Difusão , Microscopia de Fluorescência , Fotodegradação
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2021: 439-442, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34891327

RESUMO

In this contribution, we focused on optimising a dynamic flow-based shear stress system to achieve a reliable platform for cell shear modulus (stiffness) and viscosity assessment using quantitative phase imaging. The estimation of cell viscoelastic properties is influenced by distortion of the shear stress waveform, which is caused by the properties of the flow system components (i.e., syringe, flow chamber and tubing). We observed that these components have a significant influence on the measured cell viscoelastic characteristics. To suppress this effect, we applied a correction method utilizing parametric deconvolution of the flow system's optimized impulse response. Achieved results were compared with the direct fitting of the Kelvin-Voigt viscoelastic model and the basic steady-state model. The results showed that our novel parametric deconvolution approach is more robust and provides a more reliable estimation of viscosity with respect to changes in the syringe's compliance compared to Kelvin-Voigt model.


Assuntos
Técnicas de Imagem por Elasticidade , Neoplasias , Estresse Mecânico , Viscosidade
7.
Biomed Opt Express ; 12(10): 6514-6528, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34745753

RESUMO

In this paper, a novel U-Net-based method for robust adherent cell segmentation for quantitative phase microscopy image is designed and optimised. We designed and evaluated four specific post-processing pipelines. To increase the transferability to different cell types, non-deep learning transfer with adjustable parameters is used in the post-processing step. Additionally, we proposed a self-supervised pretraining technique using nonlabelled data, which is trained to reconstruct multiple image distortions and improved the segmentation performance from 0.67 to 0.70 of object-wise intersection over union. Moreover, we publish a new dataset of manually labelled images suitable for this task together with the unlabelled data for self-supervised pretraining.

8.
ACS Omega ; 6(43): 28699-28709, 2021 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-34746564

RESUMO

Interpenetrating polymer network (IPN)-based bead formulations were exploited by cross-linking different hydrophilic polymers in different combinations and at different ratios. Polyvinyl alcohol, xanthan gum, guar gum, gellan gum, and sodium alginate (Na-alginate) were used in this work as hydrophilic polymers to enhance the solubility of diclofenac sodium and also to target the delivery at preferred locations. IPN beads based on polysaccharides were prepared by the ionic gelation method. Differential scanning calorimetry, powder X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy data showed that the IPN microbeads solubilized and encapsulated the drug within the network. We found over 83% encapsulation efficiency of the drug delivery system for the drug, and this efficiency increased with the concentration of the polymer. Ex vivo experiments using the goat intestine revealed that the IPN microbeads were able to adhere to the intestinal epithelium, a mucoadhesive behavior that could be beneficial to the drug pharmacokinetics, while in vitro experiments in phosphate buffer showed that the IPN enabled significant drug release. We believe that these IPN microbeads are an excellent drug delivery system to solubilize drug molecules and ensure adhesion to the intestinal wall, thereby localizing the drug release to enhance bioavailability of poorly soluble drugs.

9.
Antibiotics (Basel) ; 10(7)2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34356736

RESUMO

Emerging infectious diseases (EID) are serious problems caused by fungi in humans and plant species. They are a severe threat to food security worldwide. In our current work, we have developed a support vector machine (SVM)-based model that attempts to design and predict therapeutic plant-derived antifungal peptides (PhytoAFP). The residue composition analysis shows the preference of C, G, K, R, and S amino acids. Position preference analysis shows that residues G, K, R, and A dominate the N-terminal. Similarly, residues N, S, C, and G prefer the C-terminal. Motif analysis reveals the presence of motifs like NYVF, NYVFP, YVFP, NYVFPA, and VFPA. We have developed two models using various input functions such as mono-, di-, and tripeptide composition, as well as binary, hybrid, and physiochemical properties, based on methods that are applied to the main data set. The TPC-based monopeptide composition model achieved more accuracy, 94.4%, with a Matthews correlation coefficient (MCC) of 0.89. Correspondingly, the second-best model based on dipeptides achieved an accuracy of 94.28% under the MCC 0.89 of the training dataset.

10.
Front Physiol ; 12: 667065, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34177617

RESUMO

AIMS: Although voltage-sensitive dye di-4-ANEPPS is a common tool for mapping cardiac electrical activity, reported effects on electrophysiological parameters are rather. The main goals of the study were to reveal effects of the dye on rabbit isolated heart and to verify, whether rabbit isolated heart stained with di-4-ANEPPS is a suitable tool for myocardial ischemia investigation. METHODS AND RESULTS: Study involved experiments on stained (n = 9) and non-stained (n = 11) Langendorff perfused rabbit isolated hearts. Electrophysiological effects of the dye were evaluated by analysis of various electrogram (EG) parameters using common paired and unpaired statistical tests. It was shown that staining the hearts with di-4-ANEPPS leads to only short-term sporadic prolongation of impulse conduction through atria and atrioventricular node. On the other hand, significant irreversible slowing of heart rate and ventricular conduction were found in stained hearts as compared to controls. In patch clamp experiments, significant inhibition of sodium current density was observed in differentiated NG108-15 cells stained by the dye. Although no significant differences in mean number of ventricular premature beats were found between the stained and the non-stained hearts in ischemia as well as in reperfusion, all abovementioned results indicate increased arrhythmogenicity. In isolated hearts during ischemia, prominent ischemic patterns appeared in the stained hearts with 3-4 min delay as compared to the non-stained ones. Moreover, the ischemic changes did not achieve the same magnitude as in controls even after 10 min of ischemia. It resulted in poor performance of ischemia detection by proposed EG parameters, as was quantified by receiver operating characteristics analysis. CONCLUSION: Our results demonstrate significant direct irreversible effect of di-4-ANEPPS on spontaneous heart rate and ventricular impulse conduction in rabbit isolated heart model. Particularly, this should be considered when di-4-ANEPPS is used in ischemia studies in rabbit. Delayed attenuated response of such hearts to ischemia might lead to misinterpretation of obtained results.

11.
Front Microbiol ; 12: 640054, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33815328

RESUMO

Gene expression analysis through reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) depends on correct data normalization by reference genes with stable expression. Although Clostridium beijerinckii NRRL B-598 is a promising Gram-positive bacterium for the industrial production of biobutanol, validated reference genes have not yet been reported. In this study, we selected 160 genes with stable expression based on an RNA sequencing (RNA-Seq) data analysis, and among them, seven genes (zmp, rpoB1, rsmB, greA, rpoB2, topB2, and rimO) were selected for experimental validation by RT-qPCR and gene ontology (GO) enrichment analysis. According to statistical analyses, zmp and greA were the most stable and suitable reference genes for RT-qPCR normalization. Furthermore, our methodology can be useful for selection of the reference genes in other strains of C. beijerinckii and it also suggests that the RNA-Seq data can be used for the initial selection of novel reference genes, however, their validation is required.

12.
Appl Microbiol Biotechnol ; 105(2): 877-889, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33409609

RESUMO

Pumping toxic substances through a cytoplasmic membrane by protein transporters known as efflux pumps represents one bacterial mechanism involved in the stress response to the presence of toxic compounds. The active efflux might also take part in exporting low-molecular-weight alcohols produced by intrinsic cell metabolism; in the case of solventogenic clostridia, predominantly acetone, butanol and ethanol (ABE). However, little is known about this active efflux, even though some evidence exists that membrane pumps might be involved in solvent tolerance. In this study, we investigated changes in overall active efflux during ABE fermentation, employing a flow cytometric protocol adjusted for Clostridia and using ethidium bromide (EB) as a fluorescence marker for quantification of direct efflux. A fluctuation in efflux during the course of standard ABE fermentation was observed, with a maximum reached during late acidogenesis, a high efflux rate during early and mid-solventogenesis and an apparent decrease in EB efflux rate in late solventogenesis. The fluctuation in efflux activity was in accordance with transcriptomic data obtained for various membrane exporters in a former study. Surprisingly, under altered cultivation conditions, when solvent production was attenuated, and extended acidogenesis was promoted, stable low efflux activity was reached after an initial peak that appeared in the stage comparable to standard ABE fermentation. This study confirmed that efflux pump activity is not constant during ABE fermentation and suggests that undisturbed solvent production might be a trigger for activation of pumps involved in solvent efflux. KEY POINTS: • Flow cytometric assay for efflux quantification in Clostridia was established. • Efflux rate peaked in late acidogenesis and in early solventogenesis. • Impaired solventogenesis led to an overall decrease in efflux.


Assuntos
Clostridium beijerinckii , Acetona , Butanóis , Clostridium , Etanol , Fermentação
13.
Genomics ; 113(1 Pt 2): 1109-1119, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33166602

RESUMO

Clostridium diolis DSM 15410 is a type strain of solventogenic clostridium capable of conducting isopropanol-butanol-ethanol fermentation. By studying its growth on different carbohydrates, we verified its ability to utilize glycerol and produce 1,3-propanediol and discovered its ability to produced isopropanol. Complete genome sequencing showed that its genome is a single circular chromosome and belongs to the cluster I (sensu scricto) of the genus Clostridium. By cultivation analysis we highlighted its specific behavior in comparison to two selected closely related strains. Despite the fact that several CRISPR loci were found, 16 putative prophages showed the ability to receive foreign DNA. Thus, the strain has the necessary features for future engineering of its 1,3-propanediol biosynthetic pathway and for the possible industrial utilization in the production of biofuels.


Assuntos
2-Propanol/metabolismo , Clostridium/genética , Genoma Bacteriano , Filogenia , Propilenoglicóis/metabolismo , Biocombustíveis , Clostridium/classificação , Clostridium/metabolismo , Microbiologia Industrial , Fenótipo
14.
Microbiologyopen ; 10(1): e1146, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33319506

RESUMO

The main bottleneck in the return of industrial butanol production from renewable feedstock through acetone-butanol-ethanol (ABE) fermentation by clostridia, such as Clostridium beijerinckii, is the low final butanol concentration. The problem is caused by the high toxicity of butanol to the production cells, and therefore, understanding the mechanisms by which clostridia react to butanol shock is of key importance. Detailed analyses of transcriptome data that were obtained after butanol shock and their comparison with data from standard ABE fermentation have resulted in new findings, while confirmed expected population responses. Although butanol shock resulted in upregulation of heat shock protein genes, their regulation is different than was assumed based on standard ABE fermentation transcriptome data. While glucose uptake, glycolysis, and acidogenesis genes were downregulated after butanol shock, solventogenesis genes were upregulated. Cyclopropanation of fatty acids and formation of plasmalogens seem to be significant processes involved in cell membrane stabilization in the presence of butanol. Surprisingly, one of the three identified Agr quorum-sensing system genes was upregulated. Upregulation of several putative butanol efflux pumps was described after butanol addition and a large putative polyketide gene cluster was found, the transcription of which seemed to depend on the concentration of butanol.


Assuntos
Transporte Biológico/genética , Butanóis/toxicidade , Membrana Celular/metabolismo , Clostridium beijerinckii/efeitos dos fármacos , Clostridium beijerinckii/genética , Reatores Biológicos/microbiologia , Clostridium beijerinckii/metabolismo , Ácidos Graxos/metabolismo , Perfilação da Expressão Gênica , Glucose/metabolismo , Glicólise/genética , Glicólise/fisiologia , Proteínas de Choque Térmico/metabolismo , Plasmalogênios/biossíntese , Percepção de Quorum/genética , Estresse Fisiológico/genética
15.
Front Bioeng Biotechnol ; 8: 598392, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33224939

RESUMO

N-Butanol, a valuable solvent and potential fuel extender, can be produced via acetone-butanol-ethanol (ABE) fermentation. One of the main drawbacks of ABE fermentation is the high toxicity of butanol to producing cells, leading to cell membrane disruption, low culture viability and, consequently, low produced concentrations of butanol. The goal of this study was to obtain mutant strains of Clostridium beijerinckii NRRL B-598 with improved butanol tolerance using random chemical mutagenesis, describe changes in their phenotypes compared to the wild-type strain and reveal changes in the genome that explain improved tolerance or other phenotypic changes. Nine mutant strains with stable improved features were obtained by three different approaches and, for two of them, ethidium bromide (EB), a known substrate of efflux pumps, was used for either selection or as a mutagenic agent. It is the first utilization of this approach for the development of butanol-tolerant mutants of solventogenic clostridia, for which generally there is a lack of knowledge about butanol efflux or efflux mechanisms and their regulation. Mutant strains exhibited increase in butanol tolerance from 36% up to 127% and the greatest improvement was achieved for the strains for which EB was used as a mutagenic agent. Additionally, increased tolerance to other substrates of efflux pumps, EB and ethanol, was observed in all mutants and higher antibiotic tolerance in some of the strains. The complete genomes of mutant strains were sequenced and revealed that improved butanol tolerance can be attributed to mutations in genes encoding typical stress responses (chemotaxis, autolysis or changes in cell membrane structure), but, also, to mutations in genes X276_07980 and X276_24400, encoding efflux pump regulators. The latter observation confirms the importance of efflux in butanol stress response of the strain and offers new targets for rational strain engineering.

16.
Stud Health Technol Inform ; 270: 1221-1222, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32570589

RESUMO

This work explores the design and implementation of an algorithm for the classification of magnetic resonance imaging data for computer-aided diagnosis of schizophrenia. Features for classification were first extracted using two morphometric methods: voxel-based morphometry (VBM) and deformation-based morphometry (DBM). These features were then transformed into a wavelet domain using the discrete wavelet transform with various numbers of decomposition levels. The number of features was then reduced by thresholding and subsequent selection by: Fisher's Discrimination Ratio (FDR), Bhattacharyya Distance, and Variances (Var.). A Support Vector Machine with a linear kernel was used for classification. The evaluation strategy was based on leave-one-out cross-validation.


Assuntos
Esquizofrenia , Humanos , Imageamento por Ressonância Magnética , Máquina de Vetores de Suporte , Análise de Ondaletas
17.
IEEE Trans Biomed Eng ; 67(10): 2721-2734, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-31995473

RESUMO

OBJECTIVE: Nowadays, methods for ECG quality assessment are mostly designed to binary distinguish between good/bad quality of the whole signal. Such classification is not suitable to long-term data collected by wearable devices. In this paper, a novel approach to estimate long-term ECG signal quality is proposed. METHODS: The real-time quality estimation is performed in a local time window by calculation of continuous signal-to-noise ratio (SNR) curve. The layout of the data quality segments is determined by analysis of SNR waveform. It is distinguished between three levels of ECG signal quality: signal suitable for full wave ECG analysis, signal suitable only for QRS detection, and signal unsuitable for further processing. RESULTS: The SNR limits for reliable QRS detection and full ECG waveform analysis are 5 and 18 dB respectively. The method was developed and tested using synthetic data and validated on real data from wearable device. CONCLUSION: The proposed solution is a robust, accurate and computationally efficient algorithm for annotation of ECG signal quality that will facilitate the subsequent tailored analysis of ECG signals recorded in free-living conditions. SIGNIFICANCE: The field of long-term ECG signals self-monitoring by wearable devices is swiftly developing. The analysis of massive amount of collected data is time consuming. It is advantageous to characterize data quality in advance and thereby limit consequent analysis to useable signals.


Assuntos
Processamento de Sinais Assistido por Computador , Dispositivos Eletrônicos Vestíveis , Algoritmos , Eletrocardiografia , Razão Sinal-Ruído , Condições Sociais
18.
Sensors (Basel) ; 19(24)2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31817539

RESUMO

Multielectrode arrays (MEAs) are devices for non-invasive electrophysiological measurements of cell populations. This paper describes a novel fabrication method of MEAs with a fully planar surface. The surface of the insulation layer and the surface of the electrodes were on one plane; we named this device the planar MEA (pMEA). The main advantage of the pMEA is that it allows uniform contact between the pMEA surface and a substrate for positioning of microfluidic channels or microprinting of a cell adhesive layer. The fabrication of the pMEA is based on a low adhesive Au sacrificial peel-off layer. In divergence from conventional MEAs with recessed electrodes, the electrodes of the pMEA lead across the sloped edge of the insulation layer. To make this, the profile of the edge of the insulation layer was measured and the impedance of the planar electrodes was characterized. The impedance of the pMEA was comparable with the impedance of conventional MEA electrodes. The pMEA was tested for patterning HL-1 cells with a combination of imprinting fibronectin and coating by antifouling poly (l-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG). The HL-1 cells remained patterned even at full confluency and presented spontaneous and synchronous beating activity.

19.
PLoS One ; 14(11): e0224560, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31697692

RESUMO

In-depth knowledge of cell metabolism and nutrient uptake mechanisms can lead to the development of a tool for improving acetone-butanol-ethanol (ABE) fermentation performance and help to overcome bottlenecks in the process, such as the high cost of substrates and low production rates. Over 300 genes potentially encoding transport of amino acids, metal ions, vitamins and carbohydrates were identified in the genome of the butanol-producing strain Clostridium beijerinckii NRRL B-598, based on similarity searches in protein function databases. Transcriptomic data of the genes were obtained during ABE fermentation by RNA-Seq experiments and covered acidogenesis, solventogenesis and sporulation. The physiological roles of the selected 81 actively expressed transport genes were established on the basis of their expression profiles at particular stages of ABE fermentation. This article describes how genes encoding the uptake of glucose, iron, riboflavin, glutamine, methionine and other nutrients take part in growth, production and stress responses of C. beijerinckii NRRL B-598. These data increase our knowledge of transport mechanisms in solventogenic Clostridium and may be used in the selection of individual genes for further research.


Assuntos
Butanóis/metabolismo , Metabolismo dos Carboidratos/genética , Clostridium beijerinckii/genética , Transcrição Gênica , Aminoácidos/genética , Aminoácidos/metabolismo , Carboidratos/genética , Clostridium beijerinckii/metabolismo , Fermentação , Regulação Bacteriana da Expressão Gênica/genética , Metais/metabolismo , Vitaminas/genética , Vitaminas/metabolismo
20.
Biotechnol Biofuels ; 12: 243, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31636702

RESUMO

BACKGROUND: One of the main obstacles preventing solventogenic clostridia from achieving higher yields in biofuel production is the toxicity of produced solvents. Unfortunately, regulatory mechanisms responsible for the shock response are poorly described on the transcriptomic level. Although the strain Clostridium beijerinckii NRRL B-598, a promising butanol producer, has been studied under different conditions in the past, its transcriptional response to a shock caused by butanol in the cultivation medium remains unknown. RESULTS: In this paper, we present a transcriptional response of the strain during a butanol challenge, caused by the addition of butanol to the cultivation medium at the very end of the acidogenic phase, using RNA-Seq. We resequenced and reassembled the genome sequence of the strain and prepared novel genome and gene ontology annotation to provide the most accurate results. When compared to samples under standard cultivation conditions, samples gathered during butanol shock represented a well-distinguished group. Using reference samples gathered directly before the addition of butanol, we identified genes that were differentially expressed in butanol challenge samples. We determined clusters of 293 down-regulated and 301 up-regulated genes whose expression was affected by the cultivation conditions. Enriched term "RNA binding" among down-regulated genes corresponded to the downturn of translation and the cluster contained a group of small acid-soluble spore proteins. This explained phenotype of the culture that had not sporulated. On the other hand, up-regulated genes were characterized by the term "protein binding" which corresponded to activation of heat-shock proteins that were identified within this cluster. CONCLUSIONS: We provided an overall transcriptional response of the strain C. beijerinckii NRRL B-598 to butanol shock, supplemented by auxiliary technologies, including high-pressure liquid chromatography and flow cytometry, to capture the corresponding phenotypic response. We identified genes whose regulation was affected by the addition of butanol to the cultivation medium and inferred related molecular functions that were significantly influenced. Additionally, using high-quality genome assembly and custom-made gene ontology annotation, we demonstrated that this settled terminology, widely used for the analysis of model organisms, could also be applied to non-model organisms and for research in the field of biofuels.

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