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1.
J Agric Food Chem ; 68(9): 2773-2782, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32013417

RESUMO

The influence of covalent protein modifications resulting from the Maillard reaction (glycation) of casein and lactose on the noncovalent association behavior of the protein was studied. Nonenzymatic cross-linking with methylglyoxal (MGO) and glutaraldehyde (GTA) as well as enzymatic cross-linking with microbial transglutaminase (mTG) was investigated in comparison. Molar mass, particle size, and conformational characteristics of nonmicellar casein associates as well as the extent of intraparticle protein cross-linking were examined utilizing size-exclusion chromatography (SEC) combined with UV detection and static and dynamic light scattering. Cross-linking resulted in the stabilization of a certain fraction of casein associates, with particle sizes of approximately 30 nm in radius of gyration (Rg), and promoted an incorporation of further casein molecules into those particles, yielding molar masses (Mw) of 1.0-1.2 × 106 g/mol. When caseins were additionally conjugated with lactose during the early Maillard reaction, a further growth of the associates up to approximately 50 nm in Rg with a Mw of 2.1 × 106 g/mol was observed. Furthermore, glycation reactions induced a transition from slightly elongated, random-coil structures toward more anisotropic conformations. Associates consisting of caseins cross-linked with GTA appeared to preserve the original particle conformation.


Assuntos
Caseínas/química , Cromatografia em Gel , Reagentes para Ligações Cruzadas/química , Difusão Dinâmica da Luz , Glutaral/química , Lactose/química , Reação de Maillard , Tamanho da Partícula , Aldeído Pirúvico/química
2.
J Surg Res ; 246: 550-559, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31668608

RESUMO

BACKGROUND: Intimal hyperplasia (IH) is the initial lesion of vein graft failure after coronary artery bypass grafting. The weak venous wall is likely one of the primary reasons for IH after exposure to the arterial environment. We investigate whether adventitial collagen cross-link by glutaraldehyde (GA) reinforces the venous wall and then reduces IH. MATERIALS AND METHODS: Adventitial collagen cross-link by 0.3% GA was performed on the rabbit jugular veins. The degree of cross-link was accessed by tensile test. The jugular vein with or without cross-link was implanted into the carotid artery of rabbit. Vein dilatation at the immediate anastomosis and pathological remodeling of vein graft after 4 wk was assessed. RESULTS: Tensile test indicated that the mechanical property of 3-min cross-linked veins more closely resembled that of the carotid artery. In rabbit arteriovenous graft models, 3-min adventitial collagen cross-link limited overdistension (diameter: 3.24 mm versus 4.65 mm, P < 0.01) at the immediate anastomosis and reduced IH (intima thickness: 78.83 µm versus 140.19 µm, P < 0.01) of vein grafts 4 wk after implantation in the cross-link group as compared with the graft group (without cross-link). Compared with the cross-link group, the expression of proliferating cell nuclear antigen and vascular cell adhesion molecule-1 increased significantly at both the mRNA and protein levels within the graft group (P < 0.01), but the expression of smooth muscle-22α decreased significantly (P < 0.01). CONCLUSIONS: Adventitial collagen cross-link by GA increased the vessel stiffness and remarkably reduced IH in a rabbit arteriovenous graft model.


Assuntos
Túnica Adventícia/efeitos dos fármacos , Colágeno/metabolismo , Reagentes para Ligações Cruzadas/administração & dosagem , Glutaral/administração & dosagem , Túnica Íntima/patologia , Túnica Adventícia/metabolismo , Animais , Artérias Carótidas/transplante , Ponte de Artéria Coronária/efeitos adversos , Modelos Animais de Doenças , Humanos , Hiperplasia/etiologia , Hiperplasia/prevenção & controle , Veias Jugulares/efeitos dos fármacos , Veias Jugulares/transplante , Masculino , Coelhos , Túnica Íntima/efeitos dos fármacos , Túnica Íntima/metabolismo , Rigidez Vascular/efeitos dos fármacos
3.
Talanta ; 207: 120305, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594628

RESUMO

The 3-aminopropyltriethoxysilane (APTES) is a common method for biomolecule immobilization on silicon and silicon derivatives such as silicon nitride (Si3N4). However, there are many parameters which impact the efficiency of APTES modification such as APTES concentration and reaction time. Thus, various APTES concentrations (0.1%, 0.5%, 1%, 2%, 5%, and 10%) under different reaction times (15, 30, 60 and 120 min) were compared to achieve the optimal APTES modification condition which produced a thin and stable APTES layer on Si3N4 surface. The modified surfaces were characterized by contact angle (CA) measurement, Fourier transform infrared (FTIR) spectroscopy and spectroscopic ellipsometry to determine the wetting property, chemical bonding composition and surface thickness, respectively. In addition, biotin was used as a model to determine the effectiveness of APTES modification condition by coupling with glutaraldehyde (GA). The Alexa Flour 488 conjugated streptavidin was performed to visualize the presence of biotin using fluorescence microscopy due to the specifically binding between biotin and streptavidin. The atomic force microscopy (AFM) was utilized to determine the surface topology which was an indicator to demonstrate the agglomeration of APTES molecule. Moreover, ion sensitive field effect transistor (ISFET) was employed as a biosensor model to demonstrate the effect between surface thickness and sensitivity of biosensor. The results show that the APTES thickness is directly correlated to the APTES concentration and reaction time. Since the importance parameter for ISFET measurement is the distance between biomolecule and sensing membrane of ISFET, the thicker APTES layer negatively impacts the sensitivity of ISFET based biosensor because of the ion shielding effect. Therefore, these results would be valuable information for development of Si3N4 biosensor, especially ISFET based biosensor.


Assuntos
Técnicas Biossensoriais/métodos , Propilaminas/química , Silanos/química , Compostos de Silício/química , Glutaral/química , Cinética , Propriedades de Superfície , Transistores Eletrônicos
4.
Biochim Biophys Acta Proteins Proteom ; 1868(1): 140251, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31299354

RESUMO

Nowadays enzymatic synthesis of nucleic acid derivatives is gaining momentum over traditional chemical synthetic processes. Biotransformations catalyzed by whole cells or enzymes offer an ecofriendly and efficient alternative to the traditional multistep chemical methods, avoiding the use of chemical reagents and organic solvents that are expensive and environmentally harmful. Herein we report for the first time the covalent immobilization a uracil phosphoribosyltransferase (UPRT). In this sense, UPRT from Thermus thermophilus HB8 was immobilized onto glutaraldehyde-activated MagReSyn®Amine magnetic iron oxide porous microparticles (MTtUPRT). According to the catalyst load experiments, MTtUPRT3 was selected as optimal biocatalyst for further studies. MTtUPRT3 was active and stable in a broad range of temperature (70-100 °C) and in the pH interval 6-8, displaying maximum activity at 100 °C and pH 7 (activity 968 IU/gsupport, retained activity 100%). In addition, MTtUPRT3 could be reused up to 8 times in the synthesis of uridine-5'-monophosphate (UMP). Finally, MTtUPRT3 was successfully applied in the sustainable synthesis of different 5-modified uridine-5'-monophosphates at short times. Taking into account these results, MTtUPRT3 would emerge as a valuable biocatalyst for the synthesis of nucleoside monophosphates through an efficient and environmentally friendly methodology.


Assuntos
Enzimas Imobilizadas/metabolismo , Pentosiltransferases/metabolismo , Thermus thermophilus/enzimologia , Uridina Monofosfato/análogos & derivados , Uridina Monofosfato/biossíntese , Biocatálise , Compostos Férricos , Glutaral , Microesferas
5.
Histochem Cell Biol ; 153(2): 121-127, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31848702

RESUMO

Epoxy-embedded semithin sections are useful for the analysis of cell and tissue organization, as well as for the processing of samples for transmission electron microscopy. Because only a very limited number of staining protocols have been developed for epoxy-embedded sections; semithin sections are used infrequently compared to conventional paraffin sections. Here, we describe a simple and reproducible polychromatic protocol for the routine staining of epoxy-embedded semithin sections by adapting Twort's staining method (mixture of neutral red and fast green FCF). The method can be used for the visualization of cellular organization as well as for the detection of elastic and collagen fibers. The proposed protocol demonstrated the best results for samples fixed for transmission electron microscopy, which suggests, as we demonstrated here, that this staining protocol can also be used for correlative light and electron microscopy.


Assuntos
Resinas Epóxi/química , Técnicas Histológicas , Tetróxido de Ósmio/química , Coloração e Rotulagem , Animais , Glutaral/química , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica , Coelhos
6.
Braz J Cardiovasc Surg ; 34(5): 610-614, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31719012

RESUMO

In cases of aortic valve disease, prosthetic valves have been increasingly used for valve replacement, however, there are inherent problems with prostheses, and their quality in the so-called Third World countries is lower in comparison to new-generation models, which leads to shorter durability. Recently, transcatheter aortic valve replacement has been explored as a less invasive option for patients with high-risk surgical profile. In this scenario, aortic valve neocuspidization (AVNeo) has emerged as another option, which can be applied to a wide spectrum of aortic valve diseases. Despite the promising results, this procedure is not widely spread among cardiac surgeons yet. Spurred on by the last publications, we went on to write an overview of the current practice of state-of-the-art AVNeo and its results.


Assuntos
Valva Aórtica/cirurgia , Anuloplastia da Valva Cardíaca/métodos , Glutaral/uso terapêutico , Doenças das Valvas Cardíacas/cirurgia , Pericárdio/transplante , Transplante Autólogo/métodos , Humanos , Reoperação , Resultado do Tratamento
7.
Exp Parasitol ; 207: 107780, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31629699

RESUMO

Plant extracts used for the treatment of helminth infections in sheep are an alternative to chemical anthelmintic drugs. Previous studies have reported the anthelmintic activity of acetone leaf extracts of Leucosidea sericea. For this study, we evaluate the ultrastructure changes induced by the acetone leaf extract of L. sericea and the component agrimol G (AG) that was isolated for the first time on adult haemonchus parasites. Adult haemonchus parasites harvested from sheep were incubated with the plant extract and AG for 3 h and evaluated by both scanning and transmission electron microscopy in comparison and in combination with albendazole or ivermectin. In all cases the method of evaluation shows ultrastructural changes, with albendazole inducing mitochondrial damage and ivermectin inducing muscle degeneration, both as previously described. Incubation with the plant extract and AG resulted in the formation of numerous non-membrane bound multi-vesicular like bodies and evenly spread disruptions/erosion in the epicuticle. Combining AG with ivermectin or albendazole resulted in an absence of effect of AG. Based on the structural changes induced by AG, together with the absence of an effect in combination with ivermectin and albendazole would suggest a disrupted microtubular network. The latter does however require biochemical confirmation.


Assuntos
Anti-Helmínticos/farmacologia , Haemonchus/efeitos dos fármacos , Floroglucinol/química , Extratos Vegetais/farmacologia , Rosaceae/química , Abomaso/parasitologia , Albendazol/farmacologia , Animais , Quimioterapia Combinada , Fixadores , Glutaral , Hemoncose/parasitologia , Hemoncose/veterinária , Haemonchus/ultraestrutura , Ivermectina/farmacologia , Microscopia Eletrônica de Varredura/veterinária , Microscopia Eletrônica de Transmissão/veterinária , Extratos Vegetais/química , Ovinos , Doenças dos Ovinos/parasitologia
8.
Mater Sci Eng C Mater Biol Appl ; 105: 110024, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546434

RESUMO

We extracted collagen (CL) from the scales of Ctenopharyngodon idella and fabricated a CL self-assembly film. Catalase (CAT) was immobilized on the films using cross-linking, adsorption, and embedding methods. The activity and operational stability of immobilized CAT were investigated, along with the influence of the concentration of glutaraldehyde (GTA) and of the initial concentration of embedded CAT. The results showed that the CL triple helix remained intact. Differential scanning calorimetry data showed that the thermal stability of CL was significantly improved by neutral salt-induced self-aggregation and GTA cross-linking. The immobilized enzyme had high activity and good operational stability. When the enzyme concentration reached 0.5 mg/mL, immobilized enzyme activity of grass carp scales reached a maximum of 2596 U/g, and after twenty-two uses, enzyme activity remained above 50%, and it could be reused >45 times (CAT = 0.5 mg/mL, GTA = 5%, Temperature = 30 °C, pH = 7). Moreover, the optimum temperature and pH of immobilized CAT were 35 °C and 7, respectively, while the same for free CAT was 30 °C and 7, respectively. This indicated that immobilization of CAT has a protective effect.


Assuntos
Escamas de Animais/química , Carpas/anatomia & histologia , Catalase/metabolismo , Colágeno/química , Enzimas Imobilizadas/metabolismo , Adsorção , Escamas de Animais/ultraestrutura , Animais , Estabilidade Enzimática , Glutaral/química , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Desnaturação Proteica , Padrões de Referência , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente
9.
Mater Sci Eng C Mater Biol Appl ; 104: 109905, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499975

RESUMO

Collagen fibrils serve as the major template for mineral deposits in both biologically derived and engineered tissues. In recent years certain non-collagenous proteins have been elucidated as important players in differentially modulating intra vs. extra-fibrillar mineralization of collagen. We and others have previously shown that the expression of the collagen receptor, discoidin domain receptor 2 (DDR2) positively correlates with matrix mineralization. The objective of this study was to examine if the ectodomain (ECD) of DDR2 modulates intra versus extra-fibrillar mineralization of collagen independent of cell-signaling. For this purpose, a decellularized collagenous substrate, namely glutaraldehyde fixed porcine pericardium (GFPP) was subjected to biomimetic mineralization protocols. GFPP was incubated in modified simulated body fluid (mSBF) or polymer-induced liquid precursor (PILP) solutions in the presence of recombinant DDR2 ECD (DDR2-Fc) to mediate extra or intra-fibrillar mineralization of collagen. Thermogravimetric analysis revealed that DDR2-Fc increased mineral content in GFPP calcified in mSBF while no significant differences were observed in PILP mediated mineralization. Electron microscopy approaches were used to evaluate the quality and quantity mineral deposits. An increase in the matrix to mineral ratio, frequency of particles and size of mineral deposits was observed in the presence of DDR2-Fc in mSBF. Von Kossa staining and immunohistochemistry analysis of adjacent sections indicated that DDR2-Fc bound to both the matrix and mineral phase of GFPP. Further, DDR2-Fc was found to bind to hydroxyapatite (HAP) particles and enhance the nucleation of mineral deposits in mSBF solutions independent of collagen. Taken together, our results elucidate DDR2 ECD as a novel player in the modulation of extra-fibrillar mineralization of collagen.


Assuntos
Materiais Biomiméticos/farmacologia , Biomineralização , Colágeno/metabolismo , Receptor com Domínio Discoidina 2/química , Animais , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/metabolismo , Glutaral/farmacologia , Humanos , Pericárdio/efeitos dos fármacos , Polímeros/farmacologia , Domínios Proteicos , Solubilidade , Análise Espectral Raman , Suínos
10.
J Pharm Biomed Anal ; 175: 112795, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31387029

RESUMO

Magnetic ligand fishing is one of the most widely used methods to screen and separate potentially bioactive compounds from complex mixtures. However, it is poorly understood the ambiguous relations between immobilized enzyme activity and fishing results (accuracy and sensitivity). Therefore, to investigate the underlying relationship of them, we fabricated the immobilized enzyme with different activities by introducing a novel support material, nickel ions (Ni2+) functionalized magnetic mesoporous silica microspheres (MMSM@PDA-Ni2+). It possesses a higher activity than the previous report because of site-directed immobilization. Then, the immobilized COX-2 with different activities were prepared using different immobilization methods, including Ni2+ affinity-oriented immobilization, polydopamine (PDA) covalent immobilization, and conventional glutaraldehyde (GA) covalent immobilization. A standard mixture (COX-2 inhibitors and noninhibitors) and green tea extract were used to compare and evaluate the fishing results systematically. It displayed the fished inhibitors were dramatically reduced with the decreased activity of immobilized COX-2, indicating that immobilized enzyme activity played a critical role in a reliable magnetic ligand fishing analysis. This development questions some of the previous studies aimed at rapid screening bioactive compounds in natural products and opens new possibilities for accurate and sensitive magnetic ligand fishing analysis. Also, the introduced novel materials with mild immobilization strategy preserve enzyme activity and spatial conformational, therefore, provides a valuable tool in future applications.


Assuntos
Inibidores de Ciclo-Oxigenase 2/química , Enzimas Imobilizadas/química , Produtos Biológicos/química , Descoberta de Drogas/métodos , Glutaral/química , Indóis/química , Ligantes , Fenômenos Magnéticos , Magnetismo/métodos , Microesferas , Níquel/química , Extratos Vegetais/química , Polímeros/química , Chá/química
11.
Adv Colloid Interface Sci ; 272: 102016, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421454

RESUMO

The design of immobilized enzyme preparations is an important and relevant area of modern sciences and technologies. Immobilization of enzymes from animal sources (component I) on natural carriers (component II) increases the system stability by protecting the active site of the enzyme from deactivation; facilitates the separation and accelerates the recovery of the enzyme. This makes reuse possible and provides a significant reduction in operating costs. Hydrolytic enzymes (such as lipases) and polysaccharides (such as chitosan) are the most promising of such pairs of components. The main attention here is devoted to the discussion on lipase immobilization on polysaccharide (mainly - chitin and chitosan). Based on the analysis of the available literature, the most adequate method is the immobilization of lipase from porcine pancreas (LPP) on polysaccharide particles (such as chitin or chitosan) pre-treated with ultrasound (to increase the particle surface area) and glutaraldehyde (for particle activation) that shows reasonably high LPP activity and stability. In order to increase further the activity of the lipase, some authors proposed to incorporate a spacer in the form of 1,3-diaminopropane (or 1,3-diaminobutane) prior to activation of the surface of the chitosan particles. In particular cases, the use of chitin (instead of chitosan) may be an alternative solution for biotechnological applications. Recently the idea of constructing "supramolecular enzyme systems" realized in the so-called "coimmobilized multienzymatic systems" strategy. The most fascinating example is the combined assay of a mixture of native LPP, glycerol kinase (from Cellulomonas) and glycerol-3-phosphate oxidase (from Aerococcus viridans) linked by glutaraldehyde to chitosan (as shell for inorganic nanoparticle core). This material was placed on a Pt-electrode as biosensor and was successfully applied for amperometric determination of the triglyceride level in the serum of healthy and diseased person. Thus, the whole innovative research-production sequence is described by Aggarwal V. and Pundir C.S.: from simple components to advanced material and further biomedical application. Thus, the following approach of lipase immobilization appears the most promising for future applications: a few types of lipases or the combination of LPP with some other enzymes immobilized simultaneously on multifunctional carriers (as nanohybrids of inorganic core and polysaccharide shell).


Assuntos
Enzimas Imobilizadas/química , Lipase/química , Lipase/metabolismo , Polissacarídeos/química , Animais , Biotecnologia/métodos , Quitina/química , Quitosana/química , Enzimas Imobilizadas/metabolismo , Glutaral/química , Nanopartículas/química , Suínos
12.
Talanta ; 205: 120126, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450397

RESUMO

Inspired by the porous and fibrous structure of commercially available bamboo, herein we created an l-glutaminase enzyme reactor based on bamboo sticks. The enzyme was immobilized onto the bamboo sticks through a glutaraldehyde modification to achieve covalent bonding. The enzymatic hydrolysis efficiency of the prepared l-glutaminase@bamboo sticks based porous enzyme reactor was evaluated by chiral ligand exchange capillary electrochromatography using l-glutamine as the substrate. l-glutaminase@bamboo exhibited improved enzymatic hydrolysis performances, including high hydrolysis efficiency (maximum rate Vmax: two fold higher than the free enzyme), prolonged stability (14 days) and good reusability. l-Glutaminase@bamboo sticks also expanded application capability in pharmaceutical industry in enzyme inhibitor screening. These excellent properties could be attributed to the micropores of bamboo sticks, which led to the fast enzymatic kinetics. The results suggest that the pores of bamboo sticks played an important role in the proposed enzyme reactor during the hydrolysis of l-glutamine and l-glutaminase inhibitor screening.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Inibidores Enzimáticos/farmacologia , Glutaminase/antagonistas & inibidores , Glutaminase/metabolismo , Poaceae/química , Estabilidade Enzimática , Enzimas Imobilizadas/antagonistas & inibidores , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Glutaminase/química , Glutaral/metabolismo , Cinética , Porosidade , Propriedades de Superfície
13.
Int J Biol Macromol ; 137: 1060-1067, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31295494

RESUMO

The physical (UV irradiation) and chemical (glutaraldehyde) modification of galactomannan (GMP) film was successfully prepared in this study. The data indicated that the UV irradiation with increasing dosage of photo-initiator could gradually consume the free hydroxyl groups in GMP to form the crosslinked networks, reducing the hydrophilic property and water vapor permeability of the modified film. The tensile strength of the obtained film with 20% sodium benzoate addition achieved 2.8 times higher than the control sample. In comparison, aldol reaction between hydroxyl groups in GMP and glutaraldehyde resulted in a homogeneous surface of films, and the introduction of glutaraldehyde significantly increased the hydrophilicity of the modified films. After chemical treatment, the value of elongation at break was remarkably enhanced by nearly 15 times, corresponding to the great flexible property against stretching.


Assuntos
Embalagem de Alimentos , Glutaral/química , Mananas/química , Raios Ultravioleta , Fenômenos Químicos , Interações Hidrofóbicas e Hidrofílicas , Fenômenos Mecânicos , Permeabilidade , Solubilidade , Vapor , Temperatura Ambiente
14.
Colloids Surf B Biointerfaces ; 182: 110339, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31284147

RESUMO

Biocompatible polymers are being used in recent times for treating skin injuries and burn wounds. Polymers like Poly Vinyl Alcohol and Chitosan are proven to be biocompatible with least toxic to treat injuries with minimal side-effects. Curcumin, a primary component of turmeric has anti-inflammatory properties and anti-microbial activity but has extremely low bioavailability. Converting Curcumin to its nano form increased its bioavailability exponentially allowing it to play a vital role in the process of wound healing. This PVA/Chi/Cur patch increased cell proliferation as shown by the results of cell line studies and MTT assay. Its anti-bacterial activity against four major bacterial strains commonly found in wound sites and water retainability indicates it to be a perfect material for wound treatment. Results of in-vivo studies conducted on wistar rats by testing the patch's healing ability on a surgically induced wound displayed its superiority over commercial ointment. This treatment for epidermal wounds reduces the frequency in which the patch has to be replaced and increases the rate of wound rehabilitation.


Assuntos
Antibacterianos/farmacologia , Anti-Inflamatórios/farmacologia , Quitosana/química , Curcumina/farmacologia , Álcool de Polivinil/química , Ferida Cirúrgica/tratamento farmacológico , Cicatrização/efeitos dos fármacos , Animais , Antibacterianos/química , Anti-Inflamatórios/química , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/crescimento & desenvolvimento , Bandagens , Reagentes para Ligações Cruzadas/química , Curcumina/química , Preparações de Ação Retardada/química , Epiderme/efeitos dos fármacos , Epiderme/lesões , Epiderme/microbiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Glutaral/química , Humanos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/crescimento & desenvolvimento , Ratos , Ratos Wistar , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Ferida Cirúrgica/microbiologia , Ferida Cirúrgica/patologia
15.
Soft Matter ; 15(36): 7127-7136, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31334536

RESUMO

Intermediate filaments are cytoskeletal proteins that are key regulators of cell mechanics, a role which is intrinsically tied to their hierarchical structure and their unique ability to accommodate large axial strains. However, how the single-filament response to applied strains translates to networks remains unclear, particularly with regards to the crosslinking role played by the filaments' disordered "tail" domains. Here we test the role of these noncovalent crosslinks in the nonlinear rheology of reconstituted networks of the intermediate filament protein vimentin, probing their stress- and rate-dependent mechanics. Similarly to previous studies we observe elastic stress-stiffening but unlike previous work we identify a characteristic yield stress σ*, above which the networks exhibit rate-dependent softening of the network, referred to as inelastic fluidization. By investigating networks formed from tail-truncated vimentin, in which noncovalent crosslinking is suppressed, and glutaraldehyde-treated vimentin, in which crosslinking is made permanent, we show that rate-dependent inelastic fluidization is a direct consequence of vimentin's transient crosslinking. Surprisingly, although the tail-tail crosslinks are individually weak, the effective timescale for stress relaxation of the network exceeds 1000 s at σ*. Vimentin networks can therefore maintain their integrity over a large range of strains (up to ∼1000%) and loading rates (10-3 to 10-1 s-1). Our results provide insight into how the hierarchical structure of vimentin networks contributes to the cell's ability to be deformable yet strong.


Assuntos
Filamentos Intermediários/metabolismo , Vimentina/química , Reagentes para Ligações Cruzadas/química , Elasticidade , Glutaral/química , Cinética , Modelos Moleculares , Multimerização Proteica , Reologia
16.
J Appl Microbiol ; 127(4): 1148-1156, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31278818

RESUMO

AIMS: This study investigated the inhibitory effect of glutaraldehyde (GA) on sour rot in citrus fruit and the underlying antifungal mechanism on mycelial growth of the causative pathogen Geotrichum citri-aurantii. METHODS AND RESULTS: Glutaraldehyde exhibited a strong inhibitory effect on G. citri-aurantii, with a minimum inhibitory and fungicidal concentration (MFC) of 1·00 µl ml-1 . In addition, in vivo application of GA (1 × MFC and 5 × MFC) reduced the disease incidence of sour rot in citrus fruit by 60 and 80% respectively. Scanning electron microscopy results revealed that the morphology of G. citri-aurantii mycelia was greatly altered by GA treatment. Propidium iodide and Calcofluor White Staining revealed that the membrane permeability, rather than the cell wall integrity, of G. citri-aurantii mycelia was severely disrupted after the addition of GA. Massive accumulation of malonaldehyde and reactive oxygen species as well as an increase in lipoxygenase activity were observed. CONCLUSION: These results indicate that GA may inhibit the mycelia growth of G. citri-aurantii through a membrane damage mechanism induced by membrane peroxidation. SIGNIFICANCE AND IMPACT OF THE STUDY: Glutaraldehyde is expected to be a novel fungicide for controlling sour rot in citrus fruit.


Assuntos
Fungicidas Industriais/farmacologia , Geotrichum/efeitos dos fármacos , Glutaral/farmacologia , Citrus/microbiologia , Geotrichum/química , Geotrichum/metabolismo , Doenças das Plantas/microbiologia
17.
Food Chem ; 300: 125249, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31352291

RESUMO

Under the optimal conditions, a crosslinked electrospun polyvinyl alcohol/cinnamon essential oil/ß-cyclodextrin (CPVA-CEO-ß-CD) nanofibrous films for sustained release of antimicrobials were successfully prepared. Cinnamon essential oil (CEO) can be sustainably released due to CPVA-CEO-ß-CD nanofibers complex delivery systems. The chemical crosslinking and physical welding achieved simultaneously by glutaraldehyde atomization fumigation, making fibers more suitable for fresh food packaging. Nanofibrous films were characterized in terms of SEM, ATR-FTIR, DSC, water contact angle analysis and antibacterial trials. ATR-FTIR and DSC data indicated that CEO was encapsulated in a ß-CD cavity and they coexisted in PVA nanofibers. The water contact angle of the crosslinked PVA nanofibrous films increased with CEO and the values were always below 90°. Crosslinked nanofibers possessed fine properties in vitro antibacterial against Staphylococcus aureus and Escherichia coli. Furthermore, CPVA/ß-CD/CEO nanofibrous films delayed decay of mushroom during storage, indicating their potential implementation in active food packaging.


Assuntos
Agaricales/fisiologia , Embalagem de Alimentos/métodos , Nanofibras/química , Álcool de Polivinil/química , beta-Ciclodextrinas/química , Antibacterianos/química , Antibacterianos/farmacologia , Cinnamomum zeylanicum/química , Reagentes para Ligações Cruzadas/química , Escherichia coli/efeitos dos fármacos , Embalagem de Alimentos/instrumentação , Armazenamento de Alimentos , Glutaral/química , Microscopia Eletrônica de Varredura , Óleos Voláteis/química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos
18.
Pak J Pharm Sci ; 32(3 (Supplementary)): 1137-1143, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31303582

RESUMO

The aim of study was cross linking of high molecular weight chitosan nanoparticles containing 5-fluorouracil to improve dissolution rate and ultimately enhance its bioavailability by reverse emulsion/micelles method and cross-linking agent i.e. glutaraldehyde (GA 25% aqueous solution in water). The nature and outer morphologies were evaluated by scanning electron microscopy (SEM). Drug release models were functional to support way from cross linked NPs. Cross linking of 5-fluorouracil with glutaraldehyde improved dissolution rate. Mean dissolution time of 5-fluorouracil decreased significantly upon reverse emulsion/cross linking as encapsulated drug is protective and thermally stable within cross linked chitosan NPs. FTIR studies showed formation of intermolecular hydrogen bonding between 5-fluorouracil and GA-co-CHNPs. DSC studies indicated a less crystalline state of 5-fluorouracil in cross linking. SEM showed spherical nanoparticles with somewhat rough surface. 5-FU release followed Korsmeyer-Peppas model which indicate diffusion and dissociation control drug release from GA-co-CH-NPs. 5-FU cross linked chitosan nanoparticles can be safe and useful tool for other chemotherapeutic agents.


Assuntos
Quitosana/química , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Fluoruracila/farmacocinética , Nanopartículas/química , Disponibilidade Biológica , Varredura Diferencial de Calorimetria , Reagentes para Ligações Cruzadas/química , Estabilidade de Medicamentos , Fluoruracila/química , Glutaral/química , Ligações de Hidrogênio , Microscopia Eletrônica de Varredura , Peso Molecular , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
19.
J Biosci Bioeng ; 128(6): 716-722, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31208799

RESUMO

Aqueous enzymatic extraction of Camellia sinensis oil was studied. The results suggested that saponin removal pretreatment assisted by ultrasound was effective in decreasing emulsification and in enhancing the free oil recovery. After 70% isopropanol extraction for 30 min under ultrasound, the residue of C. sinensis seeds was further hydrolyzed with free cellulase and Alcalase for 5 h, and calcium ions were concurrently added during enzymatic hydrolysis (nCa2+: nsaponin = 1:2), and free oil recovery up to 94.14% was obtained. Separate immobilization and co-immobilization of Alcalase and cellulase were performed by alginate entrapment combined with glutaraldehyde crosslinking. Specific activity and recovery of activity for Alcalase and cellulase were acceptable. After immobilization, Alcalase and cellulase exhibited higher activity at a wider pH and temperature range. Reuse experiments of immobilized enzymes were conducted. The deactivation kinetics immobilized enzymes were simulated and half-life of immobilized enzyme was estimated. The results indicated that a magnetic supporter facilitated the recovery of immobilized enzymes from tea seed slurry, and that immobilized Alcalase and cellulase had good reusability.


Assuntos
Camellia sinensis/química , Celulase/metabolismo , Camellia sinensis/metabolismo , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Glutaral/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Óleos Vegetais/química , Óleos Vegetais/metabolismo , Sementes/química , Sementes/metabolismo , Temperatura Ambiente
20.
PLoS One ; 14(6): e0214656, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31194770

RESUMO

Glutaraldehyde-fixed bovine pericardium is currently the most popular biomaterial utilized in the creation of bioprosthetic heart valves. However, recent studies indicate that glutaraldehyde fixation results in calcification and structural valve deterioration, limiting the longevity of bioprosthetic heart valves. Additionally, glutaraldehyde fixation renders the tissue incompatible with constructive recipient cellular repopulation, remodeling and growth. Use of unfixed xenogeneic biomaterials devoid of antigenic burden has potential to overcome the limitations of current glutaraldehyde-fixed biomaterials. Heart valves undergo billion cycles of opening and closing throughout the patient's lifetime. Therefore, understanding the response of unfixed tissues to cyclic loading is crucial to these in a heart valve leaflet configuration. In this manuscript we quantify the effect of cyclic deformation on cycle dependent strain, structural, compositional and mechanical properties of fixed and unfixed tissues. Glutaraldehyde-fixed bovine pericardium underwent marked cyclic dependent strain, resulting from significant changes in structure, composition and mechanical function of the material. Conversely, unfixed bovine pericardium underwent minimal strain and maintained its structure, composition and mechanical integrity. This manuscript demonstrates that unfixed bovine pericardium can withstand cyclic deformations equivalent to 6 months of in vivo heart valve leaflet performance.


Assuntos
Fenômenos Biomecânicos , Glutaral/farmacologia , Valvas Cardíacas/fisiologia , Preservação de Órgãos/veterinária , Animais , Fenômenos Biomecânicos/efeitos dos fármacos , Bioprótese , Bovinos , Análise de Elementos Finitos , Próteses Valvulares Cardíacas , Valvas Cardíacas/efeitos dos fármacos , Suínos , Fixação de Tecidos
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