Biosurfactants production by marine yeasts isolated from zoanthids and characterization of an emulsifier produced by Yarrowia lipolytica LMS 24B

The present study investigates the potential for biosurfactant production of 19 marine yeast species obtained from zoanthids. Using the emulsification index test to screen the samples produced by the marine yeasts, we verified that five isolates exhibited an emulsification index ≥50%. Additional tests were performed on such isolates, including oil displacement, drop collapse, Parafilm M assay, and surface tension measurement. The tolerance of produced biosurfactants for environmental conditions was also analyzed, especially considering the media's temperature, pH, and salinity. Moreover, the surfactant's ability to emulsify different hydrocarbon sources and to metabolize kerosene as the sole carbon source was evaluated in vitro. Our results demonstrate that yeast biosurfactants can emulsify hydrocarbon sources under different physicochemical conditions and metabolize kerosene as a carbon source. Considering the Yarrowia lipolytica LMS 24B as the yeast model for biosurfactant production from the cell's wall biomass, emulsification indexes of 61.2% were obtained, even at a high temperature of 120 °C. Furthermore, the Fourier-transform middle infrared spectroscopy (FTIR) analysis of the biosurfactant's chemical composition revealed the presence of distinct functional groups assigned to a glycoprotein complex. Considering the status of developing new bioproducts and bioprocesses nowadays, our findings bring a new perspective to biosurfactant production by marine yeasts, especially Y. lipolytica LMS 24B. In particular, the presented results validate the relevance of marine environments as valuable sources of genetic resources, i.e., yeast strains capable of metabolizing and emulsifying petroleum derivatives.

Design, synthesis, antiviral evaluation, and In silico studies of acrylamides targeting nsP2 from Chikungunya virus

The Togaviridae family comprises several New- and Old-World Alphaviruses that have been responsible for thousands of human illnesses, including the RNA arbovirus Chikungunya virus (CHIKV). Firstly, it was reported in Tanzania in 1952 but rapidly it spread to several countries from Europe, Asia, and the Americas. Since then, CHIKV has been circulating in diverse countries around the world, leading to increased morbidity rates. Currently, there are no FDA-approved drugs or licensed vaccines to specifically treat CHIKV infections. Thus, there is a lack of alternatives to fight against this viral disease, making it an unmet need. Structurally, CHIKV is composed of five structural proteins (E3, E2, E1, C, and 6k) and four non-structural proteins (nsP1-4), in which nsP2 represents an attractive antiviral target for designing novel inhibitors since it has an essential role in the virus replication and transcription. Herein, we used a rational drug design strategy to select some acrylamide derivatives to be synthesized and evaluated against CHIKV nsP2 and also screened on CHIKV-infected cells. Thus, two regions of modifications were considered for these types of inhibitors, based on a previous study of our group, generating 1560 possible inhibitors. Then, the 24 most promising ones were synthesized and screened by using a FRET-based enzymatic assay protocol targeting CHIKV nsP2, identifying LQM330, 333, 336, and 338 as the most potent inhibitors, with Ki values of 48.6 ± 2.8, 92.3 ± 1.4, 2.3 ± 1.5, and 181.8 ± 2.5 μM, respectively. Still, their Km and Vmax kinetic parameters were also determined, along with their competitive binding modes of CHIKV nsP2 inhibition. Then, ITC analyses revealed KD values of 127, 159, 198, and 218 μM for LQM330, 333, 336, and 338, respectively. Also, their ΔH, ΔS, and ΔG physicochemical parameters were determined. MD simulations demonstrated that these inhibitors present a stable binding mode with nsP2, interacting with important residues of this protease, according to docking analyzes. Moreover, MM/PBSA calculations displayed that van der Waals interactions are mainly responsible for stabilizing the inhibitor-nsP2 complex, and their binding energies corroborated with their Ki values, having -198.7 ± 15.68, -124.8 ± 17.27, -247.4 ± 23.78, and -100.6 ± 19.21 kcal/mol for LQM330, 333, 336, and 338, respectively. Since Sindbis (SINV) nsP2 is similar to CHIKV nsP2, these best inhibitors were screened against SINV-infected cells, and it was verified that LQM330 presented the best result, with an EC50 value of 0.95 ± 0.09 μM. Even at 50 μM concentration, LQM338 was found to be cytotoxic on Vero cells after 48 h. Then, LQM330, 333, and 336 were evaluated against CHIKV-infected cells in antiviral assays, in which LQM330 was found to be the most promising antiviral candidate in this study, exhibiting an EC50 value of 5.2 ± 0.52 μM and SI of 31.78. The intracellular flow cytometry demonstrated that LQM330 is able to reduce the CHIKV cytopathogenic effect on cells, and also reduce the percentage of CHIKV-positive cells from 66.1% ± 7.05 to 35.8% ± 5.78 at 50 μM concentration. Finally, qPCR studies demonstrated that LQM330 was capable of reducing the number of viral RNA copies/μL, suggesting that CHIKV nsP2 is targeted by this inhibitor as its mechanism of action.

Discovery and structure-activity relationship of Morita-Baylis-Hillman adducts as larvicides against dengue mosquito vector, Aedes aegypti (Diptera: Culicidae)

Neglected tropical diseases (NTDs) have become a significant public health problem worldwide, notably the life-threatening dengue hemorrhagic fever borne by the Aedes aegypti mosquito. Thus, mosquito vector control measures remain essential in public health vector surveillance and control to combat Aedes-borne infections. Therefore, a series of MBH adducts were synthesized and assessed towards the fourth instar mosquito larvae, Aedes aegypti, along with the preliminary structure-activity relationship (SAR). Noteworthy, this compound class might be synthetized by an efficient eco-friendly synthesismethod and a rapid route for the synthesis of commercial larvicide through a single synthetic step. The bioassays showed that this compound class is a promising larvicide to control Aedes aegypti mosquito larvae, mainly 3g, with an LC₅₀ of 41.35 µg/mL, which was higher than evaluated positive controls. Nevertheless, it is a viable larvicidalhit candidate for further hit-to-leadproperties optimization of its biphenyl backbone scaffold with enhanced insecticidalbioactivity. Moreover, scanning electron microscopy analysis suggested a disruption of the osmoregulatory/ionoregulatory functions by the complete deterioration of the terminal exoskeleton hindgut and anal papillae. Therefore, this new study shows the larvicidal efficacy of the tested compounds against the Aedes aegypti larvae.

Dataset of Schinus terebinthifolius essential oil microencapsulated by spray-drying

Schinus terebinthifolius Raddi has been extensively studied due to its antioxidant, anti-inflammatory and antibiotic properties. Recently, its seeds have been tested against some insect pests as an insecticide, repellent and antifungal agent. Microencapsulation by spray-drying is widely used in the food and drug industries, as well as in the microencapsulation of essential oils, since it protects the oils against several effects, such as oxidation and thermal degradation, thus optimising its use. The aim was to microencapsulate S. terebinthifolius essential oil by spray-drying maltodextrin and arabic gum as encapsulating agents and SiO₂ as a colloidal adjuvant. The morphology of the microcapsules was analysed by scanning electron microscopy (SEM), which evidenced mainly regular spherical-shaped particles with sizes between 5 and 10 µm. The thermal stability was studied by thermogravimetric analysis-differential scanning calorimetry (TGA-DSC), and the microcapsules were stable at temperatures up to 200°C. The microencapsulating agents and the spray-drying technique produced microcapsules capable of protecting the essential oil against external effects, such as thermal degradation.

Cecropia pachystachya Trécul: identification, isolation of secondary metabolites, in silico study of toxicological evaluation and interaction with the enzymes 5-LOX and α-1-antitrypsin

Cecropia pachystachya Tréc., popularly known as embaúba, belongs to the Cecropiaceae family and is used by the native population in the treatment of bronchitis, asthma, high blood pressure, fever, and as a diuretic. The pharmacological actions including anti-inflammatory, antioxidant, cardiotonic and sedative were previously reported. The objective of this study was to (1) isolate and identify bioactive compounds extracted from the ethanolic extract of C. pachystachya roots (ERCP), as well as (2) verify the affinity of these metabolites with the enzymes 5-lipoxygenase (5-LOX) and α-1-antitrypsin through in silico tests. Isolation and/or identification were performed using GC-MS, HPLC, Infrared (IR), and nuclear magnetic resonance (NMR) techniques. After isolation and identification of the active compounds, these substances were subjected to the in silico investigation that proceeded by performing PreADMET simulations and molecular docking calculations. The bioactive compounds identified were 1-(+)-ascorbic acid 2,6-dihexadecanoate, ethyl hexadecanoate, ethyl (9E,12E)-octadec-9,12-dienoate, ethyl (Z)-octadec-9-enoate and ethyl octadecanoate by GC-MS; chlorogenic acid, catechin, epicatechin, syringaldehyde by HPLC; β-sitosterol, sitostenone, beccaridiol, tormentic acid, lupeol, α- and β-amyrin by classical chromatography, IR, ¹H and ¹³C NMR techniques. The ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties were determined for each bioactive compound. Tormentic acid demonstrated a greater affinity for 5-LOX enzyme while sitostenone demonstrated a higher affinity for the α-1-antitrypsin enzyme. Our findings demonstrated a diverse range of secondary metabolites isolated from C. pachystachya that showed relevant interactions with the enzymes 5-LOX and α-1-antitrypsin. Thus, "embaúba" may be employed in in vivo experimental studies as a form of alternative treatment for chronic lung diseases.Abbreviations: ADT: Autodock Tools; BBB: Blood-brain barrier; CaCo2: Human colonic adenocarcinoma cells; CC: Classic/open Column; TLC: Thin Layer Chromatography; CD40: Differentiation Cluster 40; CENAUREMN: Centro Nordestino de Aplicação e Uso da Ressonância Magnética Nuclear; GC-MS: Gas Chromatography coupled to mass spectrometry; HPLC: High-Perfomance Liquid Chromatography; CYP2C9, CYP2C19, CYP2D6 and CYP3A4: Cytochrome P450 isoenzymes; COPD: Chronic Obstructive Pulmonary Disease; DRX-500: X-Ray Diffraction - 500; ERCP: Ethanolic extract of the roots of C. pachystachya; FAPEPI: Fundação de Amparo à Pesquisa do Piauí; HIA: Human Intestinal Absorption; IR: Infrared; Ki: Inhibition constant; 5-LOX: 5-Lipoxygenase; mM: miliMolar; nM: nanoMolar; OECD423: acute toxic class method; PDB: Protein Data Bank; P-gP: P-glycoprotein; PM2,5: Small inhalable particles 2,5; PPB: Plasm Protein Binding; PreADMET: Prediction Absorption, Distribution, Metabolization, Excretion and Toxicity; NMR: Nuclear Magnetic Resonance; +S9: with metabolic activation; -S9: no metabolic activation; SisGen: Sistema Nacional de Gestão de Patrimônio Genético e do Conhecimento Tradicional Associado; R_T: Retention time; TA100: Ames test with TA100 cells line; TA1535: Ames test with cells of the TA1535 cell line; UESPI: State University of Piauí; V79: lung fibroblast cells; ΔG: Gibbs free energy (Kcal/mol); μM: microMolar.

Propolis in Oral Healthcare: Antibacterial Activity of a Composite Resin Enriched With Brazilian Red Propolis

The aim of this study was to obtain a Brazilian red propolis (BRP) enriched composite resin and to perform the characterization of its antibacterial activity, mechanical, and physical-chemical properties. Brazilian red propolis ethyl acetate extract (EABRP) was characterized by LC-ESI-Orbitrap-FTMS, UPLC-DAD, antibacterial activity, total flavonoids content, and radical scavenging capacity. BRP was incorporated to a commercial composite resin (RC) to obtain BRP enriched composite at 0.1, 0.15 and 0.25% (RP10, RP15 and RP25, respectively). The antibacterial activity RPs was evaluated against Streptococcus mutans by contact direct test and expressed by antibacterial ratio. The RPs were characterized as its cytotoxicity against 3T3 fibroblasts, flexural strength (FS), Knoop microhardness (KHN), post-cure depth (CD), degree of conversion (DC%), water sorption (Wsp), water solubility (Wsl), average roughness (Ra), and thermal analysis. Were identified 50 chemical compounds from BRP extract by LC-ESI-Orbitrap-FTMS. EABRP was bacteriostatic and bactericide at 125 and 500 μg/ml, respectively. The RP25 exhibited antibacterial ratio of 90.76% after 1 h of direct contact with S. mutans (p < 0.0001) while RC no showed significative antibacterial activity (p = 0.1865), both compared with cell control group. RPs and RC no showed cytotoxicity. RPs exhibited CD from 2.74 to 4.48 mm, DC% from 80.70 to 83.96%, Wsp from 17.15 to 21.67 μg/mm³, Wsl from 3.66 to 4.20 μg/mm³, Ra from 14.48 to 20.76 nm. RPs showed thermal resistance between 448–455°C. The results support that propolis can be used on development of modified composite resins that show antibacterial activity and that have compatible mechanical and physical-chemical properties to the indicate for composite resins.

Layered double hydroxides for controlled fluoride release

This study aims to develop a nano-sized fluoridated layered double hydroxide (LDH)-based release system via hydrothermal treatment for the controlled delivery of fluoride (F-) ions in the oral environment. The synthesis of conventional LDH-type (C-LDH) precursor nanomaterials was conducted using a co-precipitation method at constant pH, and the nanoparticulate-LDH (N-LDH) was synthesized by a hydrothermal procedure. Fluoride LDH (F-LDH) products were obtained through indirect synthesis using the precursor ion-exchange technique by varying the agitation time (2 and 24 h) and temperature (25 and 40 °C) to produce 12 material samples. The materials were characterized by energy dispersive x-ray, hexamethyldisilazane, digital radiography x-ray, Fourier-transform infrared, thermogravimetric analysis, and scanning electron microscopy. Additionally, the F-release kinetic profile was evaluated for 21 d in neutral and acid media with mathematical model analysis. Products with varying F-quantities were obtained, revealing specific release profiles. In general, there was a higher F-release in the acid medium, with emphasis on F-LDH-8. Fluoride-LDH and controlled fluoride delivery was successfully obtained, proving the potential of these nanomaterials as alternative anti-caries agents.

Polyphenols and Brazilian red propolis incorporated into a total-etching adhesive system help in maintaining bonding durability

Objectives

The aim of this study was to evaluate the degree of conversion and bond strength of a commercial dental adhesive modified by the incorporation of quercetin, resveratrol (RES), and Brazilian red propolis (BRP).

Methods

BRP markers were identified using ultra-performance liquid chromatography coupled with a diode array detector, and the antioxidant activity (AAO) of the three substances was analyzed. Single Bond 2 adhesive (3M ESPE) was modified by adding BRP, quercetin, and RES, separately, at 20 μg/mL, 250 μg/mL, and 500 μg/mL, respectively. The degree of conversion (DC) was measured using near-infrared spectroscopy 24 h after photopolymerization. Measurements of the resin-dentin microtensile bond strength (μTBS) were carried out after 1 day and 1 year. Student's t test and ANOVA with Tukey's test were used for data analysis (α = 0.05).

Results

The markers daidzein, liquiritigenin, pinobanksin, isoliquiritigenin, formononetin, pinocembrin, and biochanin A were found in the ethanolic extract of BRP. Quercetin, RES, and BRP showed high AAO. The DC of the tested adhesives remained adequate for this category of material, with a slight increase in the DC of adhesives with quercetin and BRP (P > 0.05). Comparisons between μTBS measurements made at 1 day and 1 year showed that, contrary to the control group, μTBS values for all modified adhesives were maintained after 1 year in distilled water (P > 0.05).

Conclusions

These findings suggest that quercetin, RES, or BRP might be useful in adhesive dentistry to help improve hybrid layer resistance.

Clinical significance

Dentin bonding agents with quercetin, RES, and BRP have potential to increase the longevity of composite restorations.

Geração de Filmes de Titânia meso-macroporosa por Modelagem de Esferas de Látex

RESUMO: Este artigo trata da síntese e formação de filmes de titânia meso-macroporosa por meio da modelagem de esferas de látex. A infiltração do molde por solução precursora de titânia resultou em filmes compactos que geraram uma rede de poros invertida decorrente da remoção do molde como foi observado por medidas de Microscopia Eletrônica de Varredura (MEV). O objetivo deste  trabalho consiste em analisar a deposição de esferas de látex em substratos de vidro e eventual infiltração por solução precursora de titânia mesoporosa. O produto final foi filmes compactos com porosidade na escala micrométrica definida pelas esferas de látex. A síntese das esferas de látex realizou-se na ausência de N2 e a solução precursora de titânia foi obtida a partir do sistema ternário: HCl/P-123/1 Butanol.  A caracterização dos filmes por MEV realizou-se após a remoção dos moldes de esferas de látex por calcinação em um forno tubular. A aparência dos filmes foi compacta para o filme de 30% V/Vo e houve uma rede de poros bem definida observada na caracterização por MEV associada à presença das esferas de látex que se auto-estruturaram pela técnica de Evaporação Controlada de Solvente (ECS).  A caracterização da superfície por MEV mostrou que esferas de látex depositam em substratos vítreos e formaram uma rede de poros que poderia ser aplicada em dispositivos funcionais como: células solares, catalisadores e baterias. Há necessidade de diminuir a concentração da dispersão para formar filmes com monocamadas homogêneas que se tornem transparentes à luz visível. PALAVRAS-CHAVE: Nanotecnologia, óxido semicondutor, materiais auto-estruturados.

Recobrimento de Superfícies metálicas por Filmes de Titânia meso-macroporosa

RESUMO: O desenvolvimento de materiais porosos tem sido um dos objetivos da nanotecnologia. Existe uma necessidade cada vez mais real de entender os mecanismos que geram materiais auto-estruturados especificamente aqueles que se originam de moldes de partículas coloidais como: polímeros, sílica, titânia e silício. A importância desses moldes é produzir dispositivos com aplicações industriais como: células solares, dessalinizadores, baterias e cristais fotônicos. Uma das principais dificuldades encontradas na aplicação de partículas coloidais é produzí-las em larga escala com tamanho uniforme e depositá-las em superfícies planas para que possam cobrir homogeneamente um substrato formando domínios cristalográficos em escala micrométrica. O objetivo deste trabalho consiste em analisar a formação de filmes nanocristalinos de titânia em superfícies metálicas que foram caracterizados por Microscopia Eletrônica de Varredura (MEV). Os substratos metálicos eram placas comerciais de aço encontradas em lojas de material de construção. O substrato foi recoberto com esferas de látex infiltradas por solução precursora de titânia e posteriormente tratatado termicamente num forno tubular a 600 oC durante uma hora. Observa-se que o substrato metálico influencia a topografia do filme de titânia mesoporosa resultando em uma estrutura lamelar em que há possibilidade de interação com o meio externo. Estes resultados mostram que o substrato influencia diretamente a topografia da titânia mesoporosa que não é mais hexagonal com poros ordenados, mas lamelar possibilitando produção de membranas auto-limpantes com aplicação direta na construção civil. PALAVRAS-CHAVE: Partículas coloidais, Substrato metálico, Estrutura lamelar.

HEPATIC FATTY ACID PROFILE OF RATS FED A TRIHEPTANOIN-BASED KETOGENIC DIET

OBJECTIVE

the aim of this study was to evaluate the influence of consumption of a ketogenic diet supplemented with triheptanoin, a medium-chain anaplerotic triacylglycerol, on the liver fatty acid profile of Wistar rats.

METHODS

three groups of male Wistar rats (n = 10) were submitted to an AIN-93 control diet, a triheptanoin- based ketogenic diet, or a soybean oil-based ketogenic diet for 60 days. Excised livers were subjected to lipid extraction and methylation to obtain fatty acids methyl esters, which were subjected to gas chromatography- mass spectrometry.

RESULTS AND DISCUSSION

compared to the rats fed the control diet, those fed ketogenic diets showed a significant reduction in the concentrations of 9-hexadecenoic and 9-octadecenoic acids, whereas those fed triheptanoin showed increased levels of octadecanoic acid.

CONCLUSION

changes in the liver fatty acid profiles of the rats fed a triheptanoin-based or a soybean oil-based ketogenic diet did not seem to be related to the dietary fat source, but rather to the characteristics of the ketogenic diets themselves.