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1.
Curr Issues Mol Biol ; 44(11): 5260-5276, 2022 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-36354670

RESUMEN

Coronavirus 2019 (COVID-19) disease management is highly dependent on the immune status of the infected individual. An increase in the incidence of depression has been observed during the ongoing COVID-19 pandemic. Autoantibodies against in vitro reactive oxygen species (ROS) modified BSA and Lys as well as antibodies against receptor binding domain subunit S1 (S1-RBD) (S1-RBD-Abs) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were estimated using direct binding and competition ELISA. Serum samples were also tested for fasting blood glucose (FBG), malondialdehyde (MDA), carbonyl content (CC), interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). Significant structural changes were observed in ROS modified BSA and Lys. Female depressed subjects who were also smokers (F-D-S) showed the highest levels of oxidative stress (MDA and CC levels). Similarly, increased levels of autoantibodies against ROS modified proteins were detected in F-D-S subjects, in males who were depressed and in smokers (M-D-S) compared to the other subjects from the rest of the groups. However, contrary to this observation, levels of S1-RBD-Abs were found to be lowest in the F-D-S and M-D-S groups. During the pandemic, large numbers of individuals have experienced depression, which may induce excessive oxidative stress, causing modifications in circulatory proteins. Thus, the formation of neo-antigens is induced, which lead to the generation of autoantibodies. The concomitant effect of increased autoantibodies with elevated levels of IFN-γ and TNF-α possibly tilt the immune balance toward autoantibody generation rather than the formation of S1-RBD-Abs. Thus, it is important to identify individuals who are at risk of depression to determine immune status and facilitate the better management of COVID-19.

2.
J Diabetes Metab Disord ; 21(1): 1003-1009, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35673491

RESUMEN

Purpose: Diabetes mellitus and periodontitis are inflammatory diseases, the severity of inflammation results in the progression and persistence of both the disorders and affects bones. Diabetic complications aggravate in diabetic subjects having periodontitis; similarly, diabetic patients are more prone to developing gingivitis and periodontitis. Periodontal and diabetic inflammation disturbs bone homeostasis, which possibly involves both innate and adaptive immune responses. The pathogenic processes that link the two diseases are the focus of much research and it is likely that upregulated inflammation arising from each condition adversely affects the other. RANKL/OPG pathway plays a prominent role in periodontal and diabetic inflammation and bone resorption. Method: This review article summarises the literature on the link between inflammatory cytokines and the prevalence of disturbed bone homeostasis in diabetic patients with periodontitis. An extensive search was done in PubMed, Scopus, Medline and Google Scholar databases between April 2003 and May 2021. Result: A total of 27 articles, including pilot studies, case-control studies, cross-sectional studies, cohort studies, randomized control trials, longitudinal studies, descriptive studies and experimental studies, were included in our literature review. Conclusion: Since RANKL/OPG are cytokines and have immune responses, regulating these cytokines expression will help control diabetes, periodontitis and bone homeostasis. The growing evidence of bone loss and increased fracture risk in diabetic patients with periodontitis makes it imperative that health professionals carry out planned treatment focusing on monitoring oral health in diabetic patients; bone markers should also be evaluated in patients with chronic periodontitis with an impaired glycemic state.

3.
Int J Biol Macromol ; 184: 57-67, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-34116091

RESUMEN

ß-Galactosidase was immobilized on modified nanosilver reduced graphene oxide (Ag@rGO) nanocomposite prepared by in vitro synthesis using same enzyme. The effectiveness factor, η value of the immobilized enzyme was calculated to be 0.968, suggesting enhancement in enzyme activity after immobilization. The morphological structure of the crosslinked biopolymer was analyzed using electron microscopy and other characterization techniques. The kinetics displayed a decrease in Km value from 0.50 to 0.44 mmol L-1 while there was an increase in Vmax values from 0.031 to 0.039 µmol min-1 mL-1. The immobilized enzyme retained 85% activity after its 10th repeated use. Inhibition constant (Ki) value suggests galactose to be a more potent inhibitor of the enzyme. Despite the inhibitory potential of these hydrolysis products, the immobilized enzyme preparation retained 44.2% activity in the presence of both inhibitory sugars. The as-synthesized nanobiocatalyst was found quite effective in hydrolyzing 89% of lactose from whey. Hence, this nanobiocatalyst can be used in removing lactose from dairy waste, whey before releasing it into the water bodies. Also, the cytotoxicity and genotoxicity of Ag@rGO NC was assessed on human blood lymphocytes using flow cytometry and comet assay, respectively.


Asunto(s)
Grafito/química , Lactosa/química , Plata/química , beta-Galactosidasa/metabolismo , Biocatálisis , Enzimas Inmovilizadas/metabolismo , Humanos , Hidrólisis , Linfocitos/citología , Linfocitos/efectos de los fármacos , Nanopartículas del Metal , Nanocompuestos , Plata/farmacología
4.
J Adv Periodontol Implant Dent ; 13(1): 28-34, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35919913

RESUMEN

Background: This cross-sectional study investigated the bone mineral density (BMD) in type 2 diabetes mellitus (T2DM) subjects with or without chronic periodontitis (CP). Methods: A total of 120 subjects aged 35‒55, divided equally into four groups: i) T2DM with CP, ii) T2DM without CP, iii) CP alone, and iv) healthy patients, were included in this study. Clinical parameters like plaque index (PI), gingival index (GI), and probing pocket depth (PPD) were recorded. All the participants were evaluated for blood sugar levels using glycated hemoglobin (HbA1c) and BMD by Hologic dual-energy x-ray absorptiometry (DEXA) scan. The association of BMD with clinical periodontal parameters and HbA1c in all groups was investigated using linear correlation analysis (r). Results: The mean value of BMD (0.9020±0.0952 g/cm2) was lower in subjects with both T2DM and CP compared to T2DM and CP alone. BMD was weakly correlated with all the clinical periodontal parameters; a positive correlation was observed between BMD and GI in the T2DM and CP group (r=0.405, P=0.026) and the CP group (r=0.324, P=0.081). A weak positive correlation was observed in BMD and HbA1c in the T2DM group (r=0.261, P=0.13), T2DM and CP group (r=0.007, P=0.970), with a negative correlation to HbA1c in the CP group (r= -0.134, P=0.479). Conclusion: Diabetes mellitus impacts clinical periodontal status and bone mass, and the effect is accentuated when chronic periodontitis is present. Based on the present study, BMD is associated with T2DM and CP, but a weak correlation was observed between BMD and HbA1c and clinical periodontal parameters.

5.
Int J Biol Macromol ; 165(Pt B): 2000-2009, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-33031855

RESUMEN

Peroxidases from Ziziphus mauritiana leaves were immobilized via complexation with gellan gum, followed by crosslinking. The impact of combined complexation-crosslinking approach on the activity and stability of the peroxidases was studied by employing the biocatalyst for the degradation of acid black 1. As compared to free peroxidases, complexed and crosslinked peroxidases displayed significantly higher pH and thermal stability. Immobilized peroxidases showed a 3-fold enhancement in thermal stability upon incubation at 60 °C for 2 h. Immobilized peroxidases retained a promising reusability of about 67% when applied for 8 repeated cycles of acid black 1 decolorization and displayed higher catalytic activity than free enzyme when employed in a stirred batch process. Putative degradation scheme of acid black 1 was proposed with the help of degradation products identified by gas chromatography-mass spectrometry which confirmed the degradation of the dye into smaller molecular weight metabolites. Molecular docking studies of peroxidases with gellan gum revealed the binding site of gellan gum resides far away from the active site of the enzyme.


Asunto(s)
Técnicas de Cultivo Celular por Lotes/métodos , Colorantes/química , Peroxidasas/metabolismo , Polisacáridos Bacterianos/química , Ziziphus/enzimología , Sitios de Unión , Estabilidad de Enzimas , Enzimas Inmovilizadas/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Humanos , Concentración de Iones de Hidrógeno , Cinética , Simulación del Acoplamiento Molecular , Mutágenos/toxicidad , Espectroscopía Infrarroja por Transformada de Fourier , Temperatura
6.
J Photochem Photobiol B ; 209: 111923, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32559647

RESUMEN

The current investigation reports bactericidal and cytotoxicity evaluation of bio-enzymatically formulated nano­gold (AuNPs) using physiologically significant enzyme ß galactosidase. The AuNPs were characterized using spectroscopic and microscopic techniques. The anti-pathogenic efficacy of AuNPs as a potential drug was observed against five contagious bacterial strains of Escherichia coli, Staphylococcus aureus, group B Streptococcus, Acinetobacter baumannii and Klebsiella pneumonia. The estimation of minimum bactericidal concentration, minimum inhibitory concentration, scanning electron microscopy and fluorescence microscopy conclude enhanced bactericidal effects of green AuNPs. The cytotoxicity of AuNPs against human cervical (HeLa), breast (MCF-7) and liver (Hep 3B) cancer cells was evaluated. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was adopted to analyze antitumor potential of AuNPs. Cell nuclear morphology associated with apoptosis after treatment with NPs was assessed against MCF-7 cells through 4,6-diamidino-2-phenylindole staining. Apoptotic activity of AuNPs was determined against HeLa cells using annexin V/ propidium iodide double staining by flow cytometric analysis. The AuNPs exhibited excellent efficacy against these cell lines and future prospects of usage as potential nano-drugs and drug delivery vehicles.


Asunto(s)
Antibacterianos/farmacología , Antineoplásicos/farmacología , Oro/química , Nanopartículas del Metal/química , beta-Galactosidasa/metabolismo , Antibacterianos/química , Antineoplásicos/química , Línea Celular Tumoral , Humanos , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Transmisión , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X
7.
Mater Sci Eng C Mater Biol Appl ; 112: 110883, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32409040

RESUMEN

Candida rugosa lipase (CRL) was treated with surfactants and immobilized onto the novel formulated magnetic graphene anchored silica nanocomposite (Fe3O4/SiO2/Gr NC). For this purpose, the surface of lipase was initially coated with Triton-X 100 and cetyltrimethylammonium bromide surfactants, to stabilize enzyme in its open form and was then adsorbed onto aminated Fe3O4/SiO2/Gr NC. Glutaraldehyde (GA) was then utilized to cross-link the adsorbed lipase onto the NC. The fabricated NC and conjugated lipase was characterized by various techniques such as FT-IR, XRD, TGA, SEM, TEM, CLSM, CD and Fluorescence spectroscopy. The magnetic character of the as-synthesized NC was verified by AGM investigation. CD and fluorescence spectroscopic analysis demonstrated slight structural rearrangements in lipase upon conjugation. The surfactant stabilized immobilized lipase demonstrated significantly enhanced thermostability, tolerance to various metal ions and inhibitors. The immobilization yield obtained owing to lipase interfacial activation by Triton X 100 and CTAB was remarkably enhanced by 6-folds and 3-folds, respectively which were remarkably higher in comparison to free immobilized lipase. The fabricated nanobiocatalysts were employed to synthesise green apple flavour ester, ethyl valerate via esterification reaction. Triton X 100 stabilized immobilized lipase was a better performer in yielding green apple flavour ester, demonstrating about 90% ester yield as compared to 78% yield obtained by CTAB stabilized immobilized lipase preparation. The obtained outcomes suggested that enzyme structure was stabilized by the GA treatment if executed in the absence or in the presence of detergent, and that, in the company of detergent, a conformation of the lipase with the exposed active center to the medium provided an aggrandized catalytic performance.


Asunto(s)
Proteínas Fúngicas/química , Grafito/química , Lipasa/química , Nanocompuestos/química , Dióxido de Silicio/química , Tensoactivos/química , Biocatálisis , Estabilidad de Enzimas , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Equipo Reutilizado , Óxido Ferrosoférrico/química , Proteínas Fúngicas/metabolismo , Cinética , Lipasa/metabolismo , Magnetismo , Saccharomycetales/enzimología
8.
Int J Biol Macromol ; 158: 150-158, 2020 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-32344094

RESUMEN

Functionalized graphene oxide nano-sheets (PAni-Ag-GONC) were prepared and employed as carrier for covalent immobilization of trypsin. This low cost setting, which involves loading of high amount of enzyme on the matrix, displayed significantly enhanced thermo-stability and pH resistance. The nano-composite (NC) bound trypsin preserved 90% of activity whereas native trypsin retained only 44% of activity after 60 days of storage at a temperature of 4°C. Immobilized trypsin conserved 80.5% of activity even after its ten repeated uses. Almond protein hydrolysates prepared by native and conjugated enzyme was investigated for antioxidant activities and found that peptides resulted from NC bound trypsin displayed increase in radical scavenging activity (i.e. around 30% and 37% scavenging activity observed, respectively by native and NC bound trypsin from same concentration of peptides). This strategy provides a new approach for production of potential biopeptides which may be incorporated in drugs and functional food industries applying PAni-Ag-GONC based biocatalysis. CHEMICAL COMPOUNDS: Trichloroacetic acid (PubChem CID: 6421); Tris (hydroxymethyl)aminomethane (PubChem CID: 6503); Glycine (PubChem CID: 750); and 2,2'-diphenyl-1-picrylhydrazyl (PubChem CID: 74358); Nα- Benzoyl-DL-arginine 4-nitroanilide hydrochloride (PubChem CID: 2724371); Ammonium sulphate (PubChem CID: 6097028).

9.
Biotechnol Bioeng ; 117(6): 1877-1894, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32159220

RESUMEN

Enzyme engineering is a powerful tool to fine-tune the enzymes. It is a technique by which the stability, activity, and specificity of the enzymes can be altered. The characteristic properties of an enzyme can be amended by immobilization and protein engineering. Among them, protein engineering is the most promising, as in addition to amending the stability and activity, it is the only way to modulate the specificity and stereoselectivity of enzymes. The current review sheds light on protein engineering and the approaches applied for it on the basis of the degree of knowledge of structure and function of enzymes. Enzymes, which have been engineered are also discussed in detail and categorized on the basis of their respective applications. This will give a better insight into the revolutionary changes brought by protein engineering of enzymes in various industrial and environmental processes.


Asunto(s)
Enzimas/genética , Ingeniería de Proteínas/métodos , Animales , Biodegradación Ambiental , Biotecnología/métodos , Evolución Molecular Dirigida/métodos , Activación Enzimática , Estabilidad de Enzimas , Terapia Enzimática , Enzimas/química , Enzimas/metabolismo , Humanos
10.
Methods Enzymol ; 630: 365-405, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31931994

RESUMEN

Carbon nanotubes (CNTs) based biosensors are recognized to be a next generation building block for ultrasensitive and fast biosensing systems. This article starting with a brief history on CNTs provides an overview on the recent expansion of research in the field of CNT-based biosensors. This is followed by the discussion on structure and properties related to CNTs. Furthermore, the basic and some newly developed synthetic methods of CNTs are summarized. In this chapter, we used polyaniline cobalt multiwalled CNTs to immobilize ß-galactosidase, by adopting both noncovalent and covalent strategies. Herein, the methodologies of both techniques have been discussed in detail. The η (effectiveness factor) values for nanocomposite bound ß-galactosidase by physical adsorption and covalent method were calculated to be 0.93 and 0.97, respectively. The covalently bound ß-galactosidase retained 92% activity even after its 10th successive reuse as compared to the adsorbed enzyme which exhibited only 74% of its initial activity. CNT armored enzymes demonstrated remarkably high catalytic stability at both sides of temperature and pH-optima along with easy recovery from the reaction medium which can be utilized in various biotechnological applications. Lastly, the scientific and technological challenges in the field are discussed at the end of this chapter.


Asunto(s)
Aspergillus oryzae/enzimología , Enzimas Inmovilizadas/química , Nanotubos de Carbono/química , beta-Galactosidasa/química , Compuestos de Anilina/química , Aspergillus oryzae/química , Técnicas Biosensibles , Estabilidad de Enzimas , Nanocompuestos/química
11.
Prep Biochem Biotechnol ; 50(5): 460-467, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31876448

RESUMEN

In the present study, specialized methodology of utilizing novel nanobiocatalyst, chitosan coated magnetic graphene (Fe3O4/GO/CS), for efficacious immobilization of Trichoderma reesei cellulase, an important industrial enzyme was revealed. The cellulase was covalently immobilized onto the nanocomposite (NC) using covalent-glutaraldehyde coupling methodology. Successful immobilization of the cellulase with Fe3O4/GO/CS NC was affirmed by transmission electron microscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The nanobiocatalyst preparations exhibited significantly improved activity, retaining 78% of the initial activity as compared to its soluble counterpart. Immobilization of cellulase also highlighted significant broadening in pH, thermal and storage stability profiles. The kinetic properties of cellulase bound Fe3O4/GO/CS NC showed lower Km indicating increased affinity (1.87 times) of nanobioconjugate toward the substrate. Cellulase bound Fe3O4/GO/CS NC was able to maintain higher percentages of its primary activity after 8 repeated uses. This nanobioconjugate preparation proves to be industrially robust biocatalyst with enhanced nano-biocatalytic activity, stability and reusability attributes, which can be exploited for hydrolysis of microcrystalline cellulose providing increased amount of sugar compared to free cellulase.


Asunto(s)
Celulasa/química , Celulosa/química , Enzimas Inmovilizadas/química , Proteínas Fúngicas/química , Nanocompuestos/química , Quitosano/análogos & derivados , Grafito/química , Hidrólisis , Hypocreales/enzimología , Nanopartículas de Magnetita/química
12.
Int J Biol Macromol ; 140: 484-495, 2019 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-31408654

RESUMEN

Surface modification of multiwalled carbon nanotubes (MWCNTs) could enhance the features of the nanomaterial as carrier for enzyme immobilization. In this strategy, magnetic MWCNTs were fabricated by incorporating them with cobalt and functionalization was carried out by aminated polydopamine. The surface modified MWCNTs were then used as a carrier for the immobilization of Candida rugosa lipase (CRL) via covalent binding using glutaraldehyde. The immobilized CRL maintained high activity, which was 3-folds of free CRL. The immobilized CRL exhibited excellent thermal resistance as validated by TGA and DTA technique and was found to be active in a broad range of pH and temperatures in comparison to free CRL. Systematic characterization via FT-IR spectroscopy, CD spectroscopy, SEM, TEM and confocal laser scanning microscopy confirmed the presence of CRL on the modified MWCNTs. Immobilized CRL presented an exquisite recycling performance as after ten consecutive reuses it retained around 84% of its initial hydrolytic activity and further showed high yield enzymatic synthesis of ethyl butyrate and isoamyl acetate having characteristic pineapple and banana flavour demonstrating 78% and 75% ester yield, respectively. The present work provides a novel perspective for lipase catalyzed biotechnological applications by adding a magnetic gain to intrinsic features of MWCNTs.


Asunto(s)
Enzimas Inmovilizadas/química , Aromatizantes/química , Lipasa/química , Nanotubos de Carbono/química , Ananas/química , Biocatálisis , Butiratos/síntesis química , Butiratos/química , Cobalto/química , Estabilidad de Enzimas , Aromatizantes/síntesis química , Frutas/química , Indoles/química , Magnetismo , Musa/química , Pentanoles/síntesis química , Pentanoles/química , Polímeros/química
13.
Biochimie ; 162: 66-76, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30959081

RESUMEN

Advanced glycation end-products (AGEs) from non-enzymatic glycation are implicated in several degenerative diseases, including being a crucial contributor in secondary complications of diabetes. This has garnered significant scientific interest in inhibiting agents of AGEs to prevent and remediate disorders arising due to glycation. In the current study, inhibitory effects on AGEs formation were investigated using bio-enzymatically synthesized nanoformulations of gold (AuNPs) and silver (AgNPs) by physiologically important enzyme, ß galactosidase. Human serum albumin, most abundant protein in human blood plasma, was glycated by incubating with glucose leading to AGEs formation. The AGEs formation was significantly minimized with both AuNPs and AgNPs, as confirmed by various biophysical and biochemical techniques. Circular dichroism and Fourier transform infrared spectroscopy further affirmed antiglycation potential of AuNPs and AgNPs. The results were corroborated with thiol group, free lysine and carbonyl content estimation for native, glycated and nanoparticles (NPs) treated samples. Confocal microscopic imaging was performed to exhibit glycation inhibiting potential of the NPs. The inhibition of AGEs was observed to be slightly stronger in case of AgNPs than AuNPs with both exhibiting promising results as potential anti-glycating agents. The study sheds light on potential of non-toxic NPs being utilized as controlling agents against hyperglycemic conditions and diabetes management.


Asunto(s)
Glucemia/efectos de los fármacos , Productos Finales de Glicación Avanzada/antagonistas & inhibidores , Oro/farmacología , Nanopartículas del Metal , Albúmina Sérica Humana/química , Plata/farmacología , Dicroismo Circular/métodos , Diabetes Mellitus/tratamiento farmacológico , Productos Finales de Glicación Avanzada/sangre , Glicosilación/efectos de los fármacos , Humanos , Hiperglucemia/tratamiento farmacológico , Plata/química , Espectroscopía Infrarroja por Transformada de Fourier/métodos , beta-Galactosidasa/química
14.
Artif Cells Nanomed Biotechnol ; 47(1): 1075-1084, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30942622

RESUMEN

In this study, an attempt has been made to evaluate the effect of products of ß-galactosidase (ßGS) catalyzed reaction i.e. glucose and galactose and their structurally related compound vitamin C (VC) on the catalytic activity of native and PANI-CS-NC and PANI-CS-Ag-NC adsorbed ßGS. Results indicated a decline in catalytic activity of soluble enzyme in the presence of all investigated compounds. The order of inhibition was found to be VC < glucose < galactose. However, the immobilized preparations were found more resistant to inactivation caused by the added compounds. About 48% activity was retained by PANI-CS-Ag-NC-ßGS in the presence of galactose (5%, w/v), while the native enzyme exhibited only 18% of its original activity. A significant decrease in absorbance and fluorescence intensity was evaluated in soluble enzyme incubated in the presence of all investigated compounds. Three-dimensional fluorescence graphs, CD and FT-IR spectroscopic studies illustrated noteworthy conformational changes in the secondary structure and microenvironment of the soluble enzyme in the presence of VC and tested sugars. These results suggest that both PANI-CS-NC and PANI-CS-Ag-NC bound ßGS are more resistant to the exposure caused by the higher concentration of added glucose, galactose, and VC and, therefore, can be effectively utilized for the production of a hassle-free lactose nano-biosensor.


Asunto(s)
Compuestos de Anilina/química , Quitosano/química , Inhibidores Enzimáticos/farmacología , Nanocompuestos/química , Plata/química , beta-Galactosidasa/antagonistas & inhibidores , beta-Galactosidasa/química , Ácido Ascórbico/farmacología , Catálisis , Enzimas Inmovilizadas/antagonistas & inhibidores , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Galactosa/farmacología , Glucosa/farmacología , Unión Proteica , beta-Galactosidasa/metabolismo
15.
Mater Sci Eng C Mater Biol Appl ; 99: 25-36, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30889698

RESUMEN

Herein, as a promising support, a magnetic enzyme nanoformulation have been designed and fabricated by a poly-o-toluidine modification approach. Owing to the magnetic nature and the existence of amine functionalized groups, the as-synthesised poly(o-toluidine) functionalized magnetic nanocomposite (Fe3O4@POT) was employed as potential support for Candida rugosa lipase (CRL) immobilization to explore its application in fruit flavour esters synthesis. The morphology and structure of the Fe3O4@POT NC were examined through various analytical tools. Hydrolytic activity assays disclose that immobilized lipase demonstrated an activity yield of 120%. It is worth mentioning that CRL#Fe3O4@POT showed superior resistance to extremes of temperature and pH and different organic solvents in contrast to free CRL. The magnetic behaviour of the as-synthesised NC was affirmed by alternating gradient magnetometer analysis. It was found to own facile immobilization process, enhanced catalytic performance for the immobilized form which may be stretched to the immobilization of various vital industrial enzymes. Moreover, it retained improved recycling performance. After 10 cycles of repetitive uses, it still possessed around 90% of its initial activity for the hydrolytic reaction, since the enzyme-magnetic nanoconjugate was effortlessly obtained using a magnet from the reaction system. The formulated nanobiocatalyst was selected for the esterification reaction to synthesize the fruit flavour esters, ethyl acetoacetate and ethyl valerate. The immobilized lipase successfully synthesised flavour compounds in aqueous and n-hexane media having significant higher ester yields compared to free enzyme. The present work successfully combines an industrially prominent biocatalyst, CRL, and a novel magnetic nanocarrier, Fe3O4@POT, into an immobilized nanoformulation with upgraded catalytic properties which has excellent potential for practical industrial implications.


Asunto(s)
Biocatálisis , Enzimas Inmovilizadas/metabolismo , Lipasa/metabolismo , Nanopartículas de Magnetita/química , Nanocompuestos/química , Toluidinas/química , Candida/enzimología , Dispersión Dinámica de Luz , Estabilidad de Enzimas , Esterificación , Ésteres/análisis , Frutas/química , Concentración de Iones de Hidrógeno , Cinética , Solventes , Espectroscopía Infrarroja por Transformada de Fourier
16.
Food Chem ; 279: 312-320, 2019 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-30611496

RESUMEN

ß-Galactosidase is vital to dairy industries because it catalyzes the hydrolysis of lactose into glucose and galactose making it useful for lactose intolerant patients to consume milk and its products. The present study demonstrates the effect of metal ions commonly found in milk, namely Zn2+, K+, Ca2+ and Mn2+ on the activity of native and polyaniline chitosan nanocomposites bound Aspergillus oryzae ß-galactosidase. In polyaniline chitosan silver nanocomposite adsorbed ß-galactosidase, a multi-fold enhancement in catalytic activity was observed in the presence of cocktail of Zn2+, K+, Ca2+ and Mn2+ ions. 3D fluorescence, CD and FTIR studies established significant conformational changes in the secondary structure of polyaniline chitosan silver nanocomposite bound ß-galactosidase on addition of metal ions as compared to the native and other bound enzyme. This enhanced catalytic efficiency of the immobilized enzyme in presence of metal ions can promote its economic use for lactose hydrolysis in milk.


Asunto(s)
Metales/química , Leche/química , Nanocompuestos/química , beta-Galactosidasa/química , Compuestos de Anilina/química , Animales , Aspergillus oryzae/enzimología , Catálisis , Quitosano/química , Dicroismo Circular , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Hidrólisis , Metales/análisis , Espectroscopía Infrarroja por Transformada de Fourier , beta-Galactosidasa/metabolismo
17.
Environ Sci Pollut Res Int ; 26(4): 3517-3529, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30519913

RESUMEN

In the present study, oxido-reductive degradation of diazo dye, Direct Red 23, has been carried out by Ziziphus mauritiana peroxidases (specific activity 17.6 U mg-1). Peroxidases have been immobilized via simple adsorption and cross-linking by glutaraldehyde; adsorbed and cross-linked enzyme retained 94.28% and 91.23% of original activity, respectively. The stability of peroxidases was enhanced significantly upon immobilization; a marked widening in both pH and temperature activity profiles were observed. Adsorbed peroxidases exhibited similar pH and temperature optima as reported for the free enzyme. Thermal stability was significantly enhanced in case of cross-linked enzyme which showed 80.52% activity even after 2 h of incubation at 60 °C. Packed bed reactors containing adsorbed and cross-linked peroxidases were run over a period of 4 weeks; adsorbed peroxidases retained 52.86% activity whereas cross-linked peroxidases maintained over 77% dye decolorization ability at the end of the fourth week of its continuous operation. Gas chromatography coupled with mass spectrometry was used to analyze the degradation products; it showed the presence of four major metabolites. Degradation of dye starts with the 1-Hydroxybenzotriazole radical attack on the carbon atom of the phenolic ring bearing azo linkage, converting it into cation radical which underwent nucleophilic attack by a water molecule and results in cleavage of chromophore via symmetric and asymmetric cleavage pathways. Intermediates undergo spontaneous removal of nitrogen, deamination, and oxidation reactions to produce maleic acid as the final degradation product. Graphical abstract.


Asunto(s)
Anilidas/metabolismo , Compuestos Azo/metabolismo , Peroxidasa/metabolismo , Purificación del Agua , Ziziphus/enzimología , Adsorción , Cromatografía de Gases y Espectrometría de Masas , Estudios Longitudinales , Oxidación-Reducción , Pectinas , Temperatura , Contaminantes Químicos del Agua
18.
Colloids Surf B Biointerfaces ; 173: 733-741, 2019 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-30384270

RESUMEN

This study presents an effective method to enhance the proteolytic activity of trypsin by designing a nanobioconjugate of trypsin and polydopamine coated silver nanoparticles (Ag-PDA). Ag-PDA nanocomposite was synthesized and trypsin was covalently attached to this matrix. A multifold enhancement in enzyme activity was observed after conjugation, with an effectiveness factor of η = 5.62. Conjugated trypsin was more stable to extremes of pH and temperature as compared to normal unconjugated version. Unconjugated trypsin retained only 41% of activity after 60 days of storage at 4 °C, whereas the conjugated enzyme preserved 91% of activity. Immobilized trypsin conserved 83% of activity even after its ten repeated uses. It was found that conjugated trypsin required lower incubation periods for complete hydrolysis of casein, BSA & ovalbumin as compared to free enzyme. Contrary to this, even long hours of incubation with free trypsin were unable to completely digest these proteins. The current observations suggest that Ag-PDA conjugated trypsin could be more suitable for efficient hydrolysis of various proteins under industrial environments.


Asunto(s)
Indoles/química , Nanopartículas del Metal/química , Nanocompuestos/química , Nanoconjugados/química , Polímeros/química , Plata/química , Tripsina/química , Caseínas/química , Estabilidad de Enzimas , Enzimas Inmovilizadas/química , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Nanopartículas del Metal/ultraestructura , Nanocompuestos/ultraestructura , Nanoconjugados/ultraestructura , Ovalbúmina/química , Proteolisis , Albúmina Sérica Bovina/química , Temperatura
19.
Methods Enzymol ; 609: 83-142, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30244800

RESUMEN

The unexpected discovery of graphene and especially the follow-up explosion of interest in its properties and applications marked the beginning of a new carbon era. Graphene-based nanostructured materials are highly useful because they show great promise in the field of biotechnology and biomedicine. Owing to their unique structural features, exceptional chemical, electrical, and mechanical properties, and their ability to affect the microenvironment of biomolecules, graphene-armored nanomaterials are suitable for use in various applications, such as immobilization of enzymes, field-effect transistors, photovoltaic devices, and biosensors, which in turn is extremely vital to the development of biomedical instruments, clinical diagnosis, and disease treatment. In this chapter, we present our recently reported work to armor hydrolytic enzymes on graphene-based nanomaterial in order to develop novel scaffolds to build robust nanobiocatalysts. Synthesized graphene-Fe3O4 and polyaniline-coated silver graphene nanocomposite have been used to immobilize ß-galactosidase and lipase, using noncovalent and covalent strategies, respectively. Herein, the methodologies of both techniques have been discussed in detail. Owing to the large surface area offered by the honeycomb like structure of graphene, very high amount of enzyme has been loaded on small amounts of the nanocomposite. The stability and reusability of the fabricated nanobiocatalysts have been compared with their free forms. Nanographene-armored enzymes demonstrated high catalytic stability and easy recovery from the reaction medium and can be applied in various biotechnological applications. Lastly, future prospects and possible challenges in this rapidly developing area have also been discussed.


Asunto(s)
Técnicas Biosensibles , Grafito/química , Lipasa/química , beta-Galactosidasa/química , Enzimas Inmovilizadas/química , Compuestos Férricos/química , Nanoestructuras/química
20.
Mater Sci Eng C Mater Biol Appl ; 91: 570-578, 2018 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-30033289

RESUMEN

The fabrication of nanoparticles (NPs) has been a wide realm of studies focusing majorly on their dispersion and stabilization. The use of biological components as reducing agents has led to emergence of environment-friendly and cost-effective approaches of synthesis. The primary aim was synthesizing silver nanoparticles (AgNPs) mediated by enzyme ß galactosidase. The surface plasmon resonance peaks of AgNPs were screened using ultraviolet-visible spectroscopy against varying time of synthesis and concentration of enzyme. The mean dimension was 12.89 ±â€¯0.16 nm as determined by the transmission electron microscopy and selected area electron diffraction patterns. The obtained NPs were fine spherical and quasi-spherical assemblages as revealed by the scanning electron microscopy studies. Fourier transform infrared spectroscopy confirmed that ß galactosidase contributed to the reduction and stabilization of the silver nanoparticles. The crystallinity and presence of elemental silver was displayed by X-ray diffraction and electron dispersive spectroscopy. The antimicrobial efficacy of these AgNPs was tested against the pathogenic bacterial strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Staphylococcus epidermidis. The minimum inhibitory concentration, minimum bactericidal concentration and biofilm inhibitory activities were reported depicting enzymatically reduced AgNPs possess an excellent bactericidal activity. An alternative approach was formulated in dye wastewater treatment where the nano-assemblages were reduced within the dye solutions leading to significant decolorization of industrially important dyes; direct, reactive and acid. The cytotoxic potential of the AgNPs was evaluated on peripheral blood lymphocytes in vitro and scanning electron microscope images obtained concluded that green synthesis fabricates benign NPs at low concentrations.


Asunto(s)
Antibacterianos/farmacología , Colorantes/química , Residuos Industriales/análisis , Plata/farmacología , beta-Galactosidasa/metabolismo , Aspergillus oryzae/enzimología , Biodegradación Ambiental , Biopelículas/efectos de los fármacos , Recuento de Colonia Microbiana , Escherichia coli/efectos de los fármacos , Escherichia coli/ultraestructura , Humanos , Linfocitos/efectos de los fármacos , Linfocitos/metabolismo , Linfocitos/ultraestructura , Nanopartículas del Metal/química , Nanopartículas del Metal/toxicidad , Nanopartículas del Metal/ultraestructura , Pruebas de Sensibilidad Microbiana , Plata/toxicidad , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X
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