Publications by authors named "Kátia Flávia Fernandes"

10 Publications

  • Page 1 of 1

Larvicidal potential of cell wall degrading enzymes from Trichoderma asperellum against Aedes aegypti (Diptera: Culicidae).

Biotechnol Prog 2021 Jun 11:e3182. Epub 2021 Jun 11.

Laboratório de Química de Polímeros (LQP) - ICB2, Universidade Federal de Goiás, Goiânia, Brazil.

Aedes aegypti is a mosquito vector of arboviruses such as dengue, chikungunya, zika and yellow fever that cause important public health diseases. The incidence and gravity of these diseases justifies the search for effective measures to reduce the presence of this vector in the environment. Bioinsecticides are an effective alternative method for insect control, with added ecological benefits such as biodegradability. The current study demonstrates that a chitinolytic enzyme complex produced by the fungus Trichoderma asperellum can disrupt cuticle formation in the L3 larvae phase of A. aegypti, suggesting such biolarvicidal action could be used for mosquito control. T. asperellum was exposed to chitin from different sources. This induction of cell wall degrading enzymes, including chitinase, N-acetylglucosaminidase and β-1,3-glucanase. Groups of 20 L3 larvae of A. aegypti were exposed to varying concentrations of chitinolytic enzymes induced with commercial chitin (CWDE) and larvae cell wall degrading enzymes (L-CWDE). After 72 h of exposure to the CWDE, 100% of larvae were killed. The same percent mortality was observed after 48 h of exposure to L-CWDE at half the CWDE enzyme mixture concentration. Exoskeleton deterioration was further observed by scanning and electron microscopy. Our findings indicate that L-CWDE produced by T. asperellum reflect chitinolytic enzymes with greater specificity for L3 larval biomolecules. This specificity is characterized by the high percentage of mortality compared with CWDE treatments and also by abrupt changes in patterns of the cellular structures visualized by scanning and transmission electron microscopy. These mixtures of chitinolytic enzymes could be candidates, as adjuvant or synergistic molecules, to replace conventional chemical insecticides currently in use.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/btpr.3182DOI Listing
June 2021

Cashew Gum Polysaccharide Nanoparticles Grafted with Polypropylene Glycol as Carriers for Diclofenac Sodium.

Materials (Basel) 2021 Apr 22;14(9). Epub 2021 Apr 22.

Laboratório de Química de Polímeros, Instituto de Ciências Biológicas, ICB2, Campus Samambaia, Universidade Federal de Goiás, Goiânia 74690-900, GO, Brazil.

This investigation focuses on the development and optimization of cashew gum polysaccharide (CGP) nanoparticles grafted with polypropylene glycol (PPG) as carriers for diclofenac sodium. The optimization of parameters affecting nanoparticles formulation was performed using a central composite rotatable design (CCRD). It was demonstrated that the best formulation was achieved when 10 mg of CGP was mixed with 10 μL of PPG and homogenized at 22,000 rpm for 15 min. The physicochemical characterization evidenced that diclofenac was efficiently entrapped, as increases in the thermal stability of the drug were observed. The [email protected] nanoparticles showed a globular shape, with smooth surfaces, a hydrodynamic diameter around 275 nm, a polydispersity index (PDI) of 0.342, and a zeta potential of -5.98 mV. The kinetic studies evidenced that diclofenac release followed an anomalous transport mechanism, with a sustained release up to 68 h. These results indicated that CGP-PPG nanoparticles are an effective material for the loading/release of drugs with similar structures to diclofenac sodium.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ma14092115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8122507PMC
April 2021

Chemical characterization and pharmacological assessment of polysaccharide free, standardized cashew gum extract (Anacardium occidentale L.).

J Ethnopharmacol 2018 Mar 21;213:395-402. Epub 2017 Nov 21.

Institute of Biological Sciences, Department of Pharmacology, Federal University of Goiás, Goiânia, GO, Brazil. Electronic address:

Ethnopharmacological Relevance: The cashew gum (Anacardium occidentale L.) is used in traditional Brazilian medicine in the treatment of inflammatory conditions, asthma, diabetes, and gastrointestinal disturbances.

Aim Of The Study: In the present study, we aimed at forming a chemical characterization and investigation of the antinociceptive and anti-inflammatory activities of the aqueous extract of cashew gum without the presence of polysaccharides in its composition (CGE).

Materials And Methods: The CGE was obtained after the precipitation and removal of polysaccharides through the use of acetone. After, the acetone was removed by rotaevaporation, and the concentrated extract was lyophilized. The chemical characterization of CGE was performed by liquid chromatography mass spectrometry (LC-MS) and tandem mass spectrometry (MS/MS) analyses. Mice were used for the evaluation of the antinociceptive and anti-inflammatory activities. CGE was analyzed via the Irwin test, acetic acid-induced writhing test, formalin-induced pain test, and carrageenan-induced paw edema test. The motor activity or probable sedation was verified through the chimney, open-field, and sodium pentobarbital-induced sleep tests. We investigated if the analgesic and anti-inflammatory effects of CGE depend of reduction in PGE levels, were performed the carrageenan or PGE-induced hyperalgesia tests.

Results: The chemical characterization of CGE showed the presence of anacardic acids as the predominant phytoconstituents. The treatment with CGE (75, 150, and 300mg/kg, p.o.) inhibited the number of writhing in a dose-dependent manner. With an intermediate dose, CGE did not cause motor impairment with the chimney test or alterations in either the open-field or sodium pentobarbital-induced sleep. In the formalin-induced pain test, CGE (150mg/kg, p.o.) produced an antinociceptive effect only in the first phase of the test, suggesting anti-inflammatory activity. With the same dosage, CGE also reduced the carrageenan-induced paw edema at all hours of the test, confirming its anti-inflammatory effect. Furthermore, CGE (150mg/kg, p.o.) presented an antihyperalgic effect at all hours of the carrageenan-induced hyperalgesia test. However, this dose of CGE was not able to reduce the hyperalgesia induced by PGE, suggesting that the anti-inflammatory effect of this extract depends on the reduction in the PGE levels.

Conclusion: The anacardic acids are the predominant phytoconstituents identified in the CGE. The action mechanisms of CGE suggest the reduction in the PGE levels. These findings support the use of cashew gum in popular medicine and demonstrate that part of its antinociceptive and anti-inflammatory effects should also be attributed to the presence of anacardic acids in its composition, independent of the presence of polysaccharides.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jep.2017.11.021DOI Listing
March 2018

Mucoadhesive Properties of Thiolated Pectin-Based Pellets Prepared by Extrusion-Spheronization Technique.

J Pharm Sci 2017 05 1;106(5):1363-1370. Epub 2017 Feb 1.

School of Pharmacy, Federal University of Goiás, Goiânia, Brazil. Electronic address:

The aim of this study was to develop mucoadhesive pellets on a thiolated pectin base using the extrusion-spheronization technique. Thiolation of pectin was performed by esterification with thioglycolic acid. The molecular weight and thiol group content of the pectins were determined. Pellets containing pectin, microcrystalline cellulose, and ketoprofen were prepared and their mucoadhesive properties were evaluated through a wash-off test using porcine intestinal mucosa. The in vitro ketoprofen release was also evaluated. Thiolated pectin presented a thiol group content of 0.69 mmol/g. Thiolation caused a 13% increase in polymer molecular weight. Pellets containing thiolated pectin were still adhering to the intestinal mucosa after 480 min and showed a more gradual release of ketoprofen. Conversely, pellets prepared with nonthiolated pectin showed rapid disintegration and detached after only 15 min. It can be concluded that thiolated pectin-based pellets can be considered a potential platform for the development of mucoadhesive drug delivery systems for the oral route.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.xphs.2017.01.028DOI Listing
May 2017

A Review of the Latest Advances in Encrypted Bioactive Peptides from Protein-Rich Waste.

Int J Mol Sci 2016 Jun 16;17(6). Epub 2016 Jun 16.

Federal University of Goiás, Institute of Biological Sciences II, Goiânia 74001-970, Brazil.

Bioactive peptides are considered the new generation of biologically active regulators that not only prevent the mechanism of oxidation and microbial degradation in foods but also enhanced the treatment of various diseases and disorders, thus increasing quality of life. This review article emphasizes recent advances in bioactive peptide technology, such as: (i) new strategies for transforming bioactive peptides from residual waste into added-value products; (ii) nanotechnology for the encapsulation, protection and release of controlled peptides; and (iii) use of techniques of large-scale recovery and purification of peptides aiming at future applications to pharmaceutical and food industries.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms17060950DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926483PMC
June 2016

Lipase entrapment in PVA/Chitosan biodegradable film for reactor coatings.

Mater Sci Eng C Mater Biol Appl 2013 Apr 31;33(3):1696-701. Epub 2012 Dec 31.

Departamento de Bioquímica e Biologia Molecular, Laboratório de Química de Proteínas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970, Goiânia, GO, Brazil.

This study reports the development and characterization of novel biodegradable film, based on chitosan and polyvinyl alcohol containing lipase entrapped. The films showed a thickness of 70.4 and 79 μm to PVA/Chitosan and PVA/Chitosan/Lipase, respectively. The entrapment of lipase in PVA/Chitosan film resulted in increasing of 69.4% tensile strength (TS), and 52.4% of elongation. SEM images showed the formation of a continuous film, without pores or cracks. The lipase entrapment efficiency was estimated in 92% and the films were repeatedly used for 25 hydrolytic cycles, maintaining 62% of initial activity. The PVA/Chitosan/Lipase film was used for olive oil hydrolysis of high performance. These results indicate that PVA/Chitosan/Lipase is a promising material for biotechnology applications such as triacylglycerol hydrolysis and biodiesel production.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.msec.2012.12.082DOI Listing
April 2013

Immobilized horseradish peroxidase on discs of polyvinyl alcohol-glutaraldehyde coated with polyaniline.

ScientificWorldJournal 2012 24;2012:129706. Epub 2012 Apr 24.

Unidade Universitária de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, Caixa Postal 459, Rodovia BR 153, Km 9875132-903 Anápolis, GO, Brazil.

Discs of network polyvinyl alcohol-glutaraldehyde (PVAG) were synthesized and coated with polyaniline (PANI) using glutaraldehyde as a chemical arm (PVAG-PANIG-HRP disc). The best conditions for the immobilization were established as about 1.0 mg mL(-1) of protein, for 60 min and pH 5.5. The soluble enzyme lost all of its activity after incubation at 70°C for 15 min, whereas the PVAG-PANIG-HRP disc retained about half of the initial activity for pyrogallol. The same PVAG-PANIG-HRP disc was used consecutively three times without any activity lossbut presented 25% of the initial activity after the 7th use. PVAG-PANIG-HRP disc retained approximately 80% and 60% of its initial activity after 60 and 80 days of storage, respectively. Resorcinol, m-cresol, catechol, pyrogallol, α-naphthol, βnaphthol, and 4, 4'-diaminodiphenyl benzidine were efficiently oxidized by the PVAG-PANIG-HRP disc (from about 70% to 90%), and it was less efficient towards aniline, phenol, and 2-nitrosonaphthol.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1100/2012/129706DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3349093PMC
September 2012

Immobilization of peroxidase onto magnetite modified polyaniline.

ScientificWorldJournal 2012 12;2012:716374. Epub 2012 Mar 12.

Laboratório de Química de Proteínas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Codigo Postal 131, 74001-970 Goiânia, GO, Brazil.

The present study describes the immobilization of horseradish peroxidase (HRP) on magnetite-modified polyaniline (PANImG) activated with glutaraldehyde. After the optimization of the methodology, the immobilization of HRP on PANImG produced the same yield (25%) obtained for PANIG with an efficiency of 100% (active protein). The optimum pH for immobilization was displaced by the effect of the partition of protons produced in the microenvironment by the magnetite. The tests of repeated use have shown that PANImG-HRP can be used for 13 cycles with maintenance of 50% of the initial activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1100/2012/716374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3319987PMC
July 2012

Optimal Conditions for Continuous Immobilization of Pseudozyma hubeiensis (Strain HB85A) Lipase by Adsorption in a Packed-Bed Reactor by Response Surface Methodology.

Enzyme Res 2012 23;2012:329178. Epub 2012 Jan 23.

Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre 91501-970, RS, Brazil.

This study aimed to develop an optimal continuous process for lipase immobilization in a bed reactor in order to investigate the possibility of large-scale production. An extracellular lipase of Pseudozyma hubeiensis (strain HB85A) was immobilized by adsorption onto a polystyrene-divinylbenzene support. Furthermore, response surface methodology (RSM) was employed to optimize enzyme immobilization and evaluate the optimum temperature and pH for free and immobilized enzyme. The optimal immobilization conditions observed were 150 min incubation time, pH 4.76, and an enzyme/support ratio of 1282 U/g support. Optimal activity temperature for free and immobilized enzyme was found to be 68°C and 52°C, respectively. Optimal activity pH for free and immobilized lipase was pH 4.6 and 6.0, respectively. Lipase immobilization resulted in improved enzyme stability in the presence of nonionic detergents, at high temperatures, at acidic and neutral pH, and at high concentrations of organic solvents such as 2-propanol, methanol, and acetone.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2012/329178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3270537PMC
August 2012

Purification of Paracoccidioides brasiliensis catalase P: subsequent kinetic and stability studies.

J Biochem 2010 Mar 6;147(3):345-51. Epub 2009 Nov 6.

Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Brazil.

Catalases are essential components of the cellular equipment to cope with oxidative stress. Here we have purified a highly abundant catalase P of Paracoccidioides brasiliensis (PbCatP) that is preferentially expressed in the parasitic yeast phase. This oxidative stress-induced protein was isolated from yeast cells grown in the presence of 15 mM of hydrogen peroxide (H(2)O(2)). We have used consecutive steps of protein precipitation and gel filtration chromatography to achieve the purified protein. Protein purification was validated using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and bioinformatics analysis. The purified enzyme showed strong similarity to small-subunit catalases. Like most monofunctional catalases, PbCatP is a homotetramer, resistant to inactivation by acidic conditions, temperature and denaturants. Furthermore, the kinetic behaviour of catalase P was observed to be different at low compared to high H(2)O(2) concentrations. The results demonstrated that a purified PbCatP is a homotetrameric enzyme, classified as a small subunit catalase.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jb/mvp182DOI Listing
March 2010
-->