Laponite-Modified Biopolymers as a Conformable Substrate for Optoelectronic Devices.

Biopolymers such as carboxymethyl cellulose and hyaluronic acid are alternative substrates for conformable organic light-emitting diodes (OLEDs). However, drawbacks such as mechanical stress susceptibility can hinder the device's performance under stretched conditions. To overcome these limitations, herein, we developed a nanocomposite based on CMC/HA (carboxymethyl cellulose/hyaluronic acid) and synthetic Laponite, intending to improve the mechanical strength without compromising the film flexibility and transparency (transmittance >80%; 380-700 nm) as substrates for conformable OLEDs. From XRD, FTIR, CP-MAS NMR, and TGA/DTG characterization techniques, it was possible to conclude the presence of Laponite randomly dispersed between the polymer chains. CMC/HA with 5% (w/w) Laponite, CMC/HA 5, presented a higher tensile strength (370.6 MPa) and comparable Young's modulus (51.0 ± 1.2 MPa) in comparison to the nanocomposites and pristine films, indicating a better candidate for the device's substrates. To produce the OLED, the multilayer structure ITO/MoO3/NPB/TCTA:Ir(ppy)3/TPBi:Ir(ppy)3/BPhen/LiF was deposited onto the CMC/HA 5 substrate. The OLEDs fabricated using CMC/HA 5 substrates showed higher luminance (12 kcd/m2) and irradiance (0.9 mW/cm2) values when compared with those based on commercial bacterial cellulose. However, the same device presented a lower efficiency (3.2 cd/A) due to a higher current density. Moreover, the OLED fabricated onto the Laponite-modified biopolymer presented reproducible behavior when submitted to continuous bending stress. Thus, CMC/HA 5 demonstrates potential as a transparent conductor substrate for biopolymer-based OLEDs with comparable performance to commercial bacterial cellulose features.

Prebiotic Activity of Pequi (Caryocar brasiliense Camb.) Shell on Lactobacillus and Bifidobacterium Strains: A Medicinal Food Ingredient.

Pequi is a native and popular fruit in Cerrado biome. The internal yellow-orange mesocarp is the edible fraction of the fruit, but its shell (peel and external mesocarp), which comprises 80% of the fruit, is not used by the agro-industry during fruit processing. There is a growing interest in the reduction of food loss and waste because of environmental, economic, and social impacts. So this study evaluated the chemical composition, antioxidant capacity, and in vitro prebiotic activity of pequi shell flour. Pequi shell flour was obtained from the lyophilization and milling of pequi shell. The content of dietary fibers, oligosaccharides, sugars, organic acids, total phenolics and tannins, polyphenol profile, and antioxidant capacity was determined in pequi shell flour. In addition, its prebiotic activity was evaluated on growth and metabolism of probiotics Lactobacillus and Bifidobacterium strains. Pequi shell flour has a high content of dietary fibers (47.92 g/100 g), soluble fibers (18.65 g/100 g), raffinose (2.39 g/100 g), and phenolic compounds (14,062.40 mg gallic acid equivalents/100 g). For the first time, the polyphenols epigallocatechin gallate, epicatechin, and procyanidin B2 were identified in this by-product. Pequi shell flour promoted greater growth of Lacticaseibacillus casei L-26 (at 24-48 h) and Bifidobacterium animalis subsp. lactis BB-12, as well as higher prebiotic activity scores than fructooligosaccharides (standard prebiotic). Pequi shell flour is rich in prebiotic compounds and has a high antioxidant and prebiotic potential. The promising results encourage its use as an ingredient with antioxidant and potential prebiotic properties to elaborate new functional foods and nutraceuticals.

Baru (Dipteryx alata Vog.) agro-industrial by-products promote the growth and metabolism of probiotic strains.

AIMS: To evaluate the phytochemical composition and effects of the baru peel and pulp (BPP) and the partially defatted baru nut (DBN) on the growth and metabolism of probiotics. METHODS AND RESULTS: The proximate composition, including dietary fibers, and polyphenol profile were determined in the BPP and DBN, and the prebiotic activity was evaluated on the growth and metabolism of the Lactobacillus and Bifidobacterium strains. BPP and DBN have a high content of insoluble fibers and phenolic compounds, mainly flavonoids and phenolic acids. Moreover, DBN stands out for its high content of proteins and lipids. BPP and DBN stimulated the growth and metabolism of Bifidobacterium animalis subsp. lactis BB-12, Lactobacillus acidophilus LA-05, and Lacticaseibacillus casei L-26. CONCLUSIONS: Baru by-products have potential prebiotic properties to be confirmed in preclinical and clinical studies, and to be explored as an ingredient in new health-promoting foods. IMPACT STATEMENT: Agro-industrial baru wastes, the peel plus pulp and the partially defatted nut, are sources of health-promoting compounds and stimulate the growth and metabolism of probiotics, indicating prebiotic properties.

Fibrin and Transforming Growth Factor Alpha Affect Prostatic Smooth Muscle Cell's Phenotype and Motility.

Smooth muscle cells (SMCs) are dynamic and transition from a contractile to a synthetic phenotype under different circumstances. Plasma factors (fibrin and transforming growth factors, TGFs) are possible components affecting SMCs differentiation and behavior. Thus, the objective of this work was to investigate how the fibrin matrix and TGFs affect SMCs differentiation and motility behavior. SMCs invaded the fibrin gel and adopted a stellate phenotype while reducing the expression of differentiation markers (Acta2, Myh11, and Smtn). At the ultrastructural level, SMCs did not assemble a basal lamina and showed numerous blebs along the entire cell surface. This transition was not associated with changes in focal adhesion kinase (FAK) content and phosphorylation status but reflected a marked change in FAK distribution in the cytoplasm. After 48 h in culture, SMCs caused an active degradation of the fibrin gel. Additionally, we tested the SMCs response to TGFs in a cell layer wound repair assay. TGFα, but not TGFß1 or TGFß3, had significantly increased motility. In conclusion, prostatic SMCs present a phenotypical transition when cultured on fibrin, adopting a micro-blebbing based motility behavior and increasing migration in response to TGFα.

Polarization, migration, and homotypical interactions among prostatic smooth muscle cells in a laminin 111-rich extracellular matrix.

Prostate cancer is a life-threatening condition worldwide. As the tumor progresses, smooth muscle cells (SMCs) become atrophic/dedifferentiated, within a series of stromal changes named stromal reaction. Here, we tested whether a laminin 111-rich extracellular matrix (Lr-ECM) could affect SMCs phenotype and differentiation status. Using time-lapse microscopy, image analyses, quantitative real-time reverse transcription polymerase chain reaction, immunohistochemistry and immunoblotting, and transmission electron microscopy, we showed that SMCs acquires a migratory behavior with a decreased expression of differentiation markers and relocation of focal adhesion kinase. SMCs set homotypic cell junctions and were active in autophagy/phagocytosis. Analysis of the migratory behavior showed that SMCs polarized and migrated toward each other, recognizing long-distance signals such as matrix tensioning. However, half of the cell population were immotile, irrespective of the nearest neighbor distance, suggesting they do not engage in productive interactions, possibly as a result of back-to-back positioning. In conclusion, the Lr-ECM, mimics the effects of the proliferating and infiltrating tumor epithelium, causing SMCs phenotypical change similar to that observed in the stromal reaction, in addition to a hitherto undescribed, stereotyped pattern of cell motility resulting from cell polarization.

Design of chitosan-based particle systems: A review of the physicochemical foundations for tailored properties.

Chitosan-based particles are widely proposed as biocompatible drug delivery systems with mucoadhesive and permeation enhancing properties. However, strategies on how to modulate the intended biological responses are still scarce. Considering that particle properties affect the biological outcome, the rational design of the synthesis variables should be proposed to engineer drug delivery systems with improved biological performance. The purpose of this review is to establish a deeper understanding of possible correlations between these variables and the particle properties from theoretical and experimental perspectives. The fundamental physicochemical knowledge of chitosan-based polyelectrolyte complexation and surface modification is discussed focusing on chitosan-TPP, polyelectrolyte complexes, and chitosan-surface modified PLGA or lipid particles. A set of design considerations is proposed to enable future investigation in the development of chitosan particles with modulated properties. The approach presented here contributes to the rational design of chitosan-based particles that meet different requirements for biological activities.

High-Lard and High-Cholesterol Diet, but not High-Lard Diet, Leads to Metabolic Disorders in a Modified Dyslipidemia Model / Dieta Rica em Banha e Colesterol, mas não Dieta Rica em Banha, Leva a Distúrbios Metabólicos em um Modelo Modificado de Dislipidemia

Abstract Background: In view of the increased global prevalence of cardiovascular and hepatic diseases, the diet lipid content and its relationship with the accumulation of fat in hepatocytes have been investigated as key factors in preventing these diseases. Objective: To evaluate the metabolic effects of a high-lard diet supplemented or not with cholesterol on a modified dyslipidemia model. Methods: We divided 24 adult male Wistar rats into three groups: standard diet (STD - 4% lipids), high-lard diet (HLD - 21% lard), and high-lard and high-cholesterol diet (HL/HCD - 20% lard, 1% cholesterol, 0.1% cholic acid). After six weeks of treatment, blood and liver were collected for biochemical (serum lipid profile and liver enzymes) and morphological analyses. Statistical analysis included one-way analysis of variance (ANOVA), followed by Tukey test for mean comparisons, and a 5% probability was considered statistically significant. Results: Animals fed HL/HCD showed increased total cholesterol, triacylglycerol, LDL-c, non-HDL-c, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) serum levels compared to those fed STD. In addition, the HL/HCD animals presented higher relative liver weight, with moderate macrovesicular hepatic steatosis and inflammatory infiltrate. Conclusion: A high-fat diet with lard (20%) and cholesterol (1%) triggered dyslipidemia with severe liver damage in rats in a shorter experimental time than the previously reported models. The high-lard diet without supplementation of cholesterol led to body weight gain, but not to dyslipidemia.

Resumo Fundamento: Tendo em vista o aumento da prevalência global de doenças cardiovasculares e hepáticas, o conteúdo lipídico da dieta e sua relação com o acúmulo de gordura nos hepatócitos têm sido investigados como fatores-chave na prevenção dessas doenças. Objetivo: Avaliar os efeitos metabólicos de uma dieta rica em banha suplementada com colesterol ou não, em um modelo modificado de dislipidemia. Métodos: Foram divididos 24 ratos Wistar machos adultos em três grupos: dieta padrão (DP - 4% de lipídios), dieta rica em banha (DRB - 21% de banha) e dieta rica em banha e colesterol (DRB/RC - 20% de banha, 1% de colesterol e 0,1% de ácido cólico). Após seis semanas de tratamento, o sangue e o fígado foram coletados para análises bioquímicas (perfil lipídico sérico e enzimas hepáticas) e morfológicas. A análise estatística incluiu análise de variância unidirecional (ANOVA), seguida do teste de Tukey para comparações de médias. Uma probabilidade de 5% foi considerada estatisticamente significativa. Resultados: Animais alimentados com DRB/RC apresentaram um aumento nos níveis séricos de colesterol total, triacilglicerol, LDL-c, não-HDL-c, alanina aminotransferase (ALT) e aspartato aminotransferase (AST) em comparação com aqueles alimentados com DP. Além disso, os animais tratados com DRB/RC apresentaram um peso relativo do fígado maior, com esteatose hepática macrovesicular moderada e infiltrado inflamatório. Conclusão: Uma dieta rica em gordura com banha (20%) e colesterol (1%) desencadeou dislipidemia com danos graves ao fígado em ratos em um tempo experimental menor do que os modelos previamente relatados. A dieta rica em banha sem suplementação de colesterol levou ao ganho de peso corporal, mas não à dislipidemia.

High-Lard and High-Cholesterol Diet, but not High-Lard Diet, Leads to Metabolic Disorders in a Modified Dyslipidemia Model.

BACKGROUND: In view of the increased global prevalence of cardiovascular and hepatic diseases, the diet lipid content and its relationship with the accumulation of fat in hepatocytes have been investigated as key factors in preventing these diseases. OBJECTIVE: To evaluate the metabolic effects of a high-lard diet supplemented or not with cholesterol on a modified dyslipidemia model. METHODS: We divided 24 adult male Wistar rats into three groups: standard diet (STD - 4% lipids), high-lard diet (HLD - 21% lard), and high-lard and high-cholesterol diet (HL/HCD - 20% lard, 1% cholesterol, 0.1% cholic acid). After six weeks of treatment, blood and liver were collected for biochemical (serum lipid profile and liver enzymes) and morphological analyses. Statistical analysis included one-way analysis of variance (ANOVA), followed by Tukey test for mean comparisons, and a 5% probability was considered statistically significant. RESULTS: Animals fed HL/HCD showed increased total cholesterol, triacylglycerol, LDL-c, non-HDL-c, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) serum levels compared to those fed STD. In addition, the HL/HCD animals presented higher relative liver weight, with moderate macrovesicular hepatic steatosis and inflammatory infiltrate. CONCLUSION: A high-fat diet with lard (20%) and cholesterol (1%) triggered dyslipidemia with severe liver damage in rats in a shorter experimental time than the previously reported models. The high-lard diet without supplementation of cholesterol led to body weight gain, but not to dyslipidemia.

Peri/epicellular protein disulfide isomerase-A1 acts as an upstream organizer of cytoskeletal mechanoadaptation in vascular smooth muscle cells.

Although redox processes closely interplay with mechanoresponses to control vascular remodeling, redox pathways coupling mechanostimulation to cellular cytoskeletal organization remain unclear. The peri/epicellular pool of protein disulfide isomerase-A1 (pecPDIA1) supports postinjury vessel remodeling. Using distinct models, we investigated whether pecPDIA1 could work as a redox-dependent organizer of cytoskeletal mechanoresponses. In vascular smooth muscle cells (VSMCs), pecPDIA1 immunoneutralization impaired stress fiber assembly in response to equibiaxial stretch and, under uniaxial stretch, significantly perturbed cell repositioning perpendicularly to stretch orientation. During cyclic stretch, pecPDIA1 supported thiol oxidation of the known mechanosensor ß1-integrin and promoted polarized compartmentalization of sulfenylated proteins. Using traction force microscopy, we showed that pecPDIA1 organizes intracellular force distribution. The net contractile moment ratio of platelet-derived growth factor-exposed to basal VSMCs decreased from 0.90 ± 0.09 (IgG-exposed controls) to 0.70 ± 0.08 after pecPDI neutralization ( P < 0.05), together with an enhanced coefficient of variation for distribution of force modules, suggesting increased noise. Moreover, in a single cell model, pecPDIA1 neutralization impaired migration persistence without affecting total distance or velocity, whereas siRNA-mediated total PDIA1 silencing disabled all such variables of VSMC migration. Neither expression nor total activity of the master mechanotransmitter/regulator RhoA was affected by pecPDIA1 neutralization. However, cyclic stretch-induced focal distribution of membrane-bound RhoA was disrupted by pecPDI inhibition, which promoted a nonpolarized pattern of RhoA/caveolin-3 cluster colocalization. Accordingly, FRET biosensors showed that pecPDIA1 supports localized RhoA activity at cell protrusions versus perinuclear regions. Thus, pecPDI acts as a thiol redox-dependent organizer and noise reducer mechanism of cytoskeletal repositioning, oxidant generation, and localized RhoA activation during a variety of VSMC mechanoresponses. NEW & NOTEWORTHY Effects of a peri/epicellular pool of protein disulfide isomerase-A1 (pecPDIA1) during mechanoregulation in vascular smooth muscle cells (VSMCs) were highlighted using approaches such as equibiaxial and uniaxial stretch, random single cell migration, and traction force microscopy. pecPDIA1 regulates organization of the cytoskeleton and minimizes the noise of cell alignment, migration directionality, and persistence. pecPDIA1 mechanisms involve redox control of ß1-integrin and localized RhoA activation. pecPDIA1 acts as a novel organizer of mechanoadaptation responses in VSMCs.

Supramolecular cyclodextrin-based metal-organic frameworks as efficient carrier for anti-inflammatory drugs.

Drug delivery systems have been used to reduce adverse effects and improve the efficacy of therapies. Drug carriers have been developed over the years, but they have limitations. γ-cyclodextrin-based metal-organic frameworks (γ-CD-MOF) have significant advantages due to their biocompatibility and environmental safety, besides crystallinity and porosity. Herein, γ-CD-MOFs were synthesised with different metals as nodes and investigated. Uniform mesoporous γ-CD-MOFs were obtained and showed an absence of toxicity in HepG2 and Caco-2 cells. The longer controlled release was verified for γ-CD-MOFs, with a maximum of 62% released in 12 h. An inflammation experiment was performed in mice and activity equivalent to the positive control was verified. γ-KCD-MOFs and γ-NaCD-MOFs reached activity after 6 h of administration, however this happened after 24 h in γ-FeCD-MOFs, being more effective than the positive control. Considering the ability for drug entrapment, easy preparation and controlled release, this class of material allows potential applications in drug delivery systems.

Resistant starch/pectin free-standing films reinforced with nanocellulose intended for colonic methotrexate release.

Although resistant starch/pectin (RS/P) films have previously displayed suitable properties for colon-specific drug delivery, nanocomposite films were developed aiming to enhance physicochemical, thermal, mechanical and barrier properties, as well as the low oral bioavailability of methotrexate (MTX). FEG-SEM micrographs of nanocomposite films showed different interaction patterns occurring among nanocellulose and RS/P. The nanofiller addition led to an increase in the thermal stability, probably due to its interaction with RS crystalline double helices. Results also displayed an improvement of the puncture strength, while barrier properties revealed a low water vapor permeability. Ex vivo bioadhesion test displayed the nanocomposites films to interact strongly with porcine gastrointestinal mucosa. In vitro drug release studies showed that the films developed enhanced the drug dissolution rates with approximately 80% of MTX release in 150min, suggesting the potential of these materials as a poor solubility drugs carrier, which constitutes an important tool for enhancing oral bioavailability.

αB-Crystallin interacts and attenuates the tyrosine phosphatase activity of Shp2 in cardiomyocytes under mechanical stress.

The small heat shock protein αB-Crystallin (CryAB, HspB5) and SH2 domain-containing tyrosine phosphatase 2 (Shp2) are important molecules in heart response to pathophysiological stress. Here we show that CryAB interacts with and potentially regulates Shp2 catalytic activity in stretched cardiomyocytes. Such an interaction requires CryAB oligomer to attenuate Shp2 activation. Stretched cardiomyocytes show a robust CryAB/Shp2 association accompanied by a reduction in the Shp2 phosphatase activity. Accordingly, CryAB knock-down in cardiomyocytes enhances Shp2 activity induced by mechanical stress. These results revealed a new role for CryAB, as a modulator of Shp2 phosphatase activity during a functionally relevant stimulus in cardiomyocytes.

αB-crystallin interacts with and prevents stress-activated proteolysis of focal adhesion kinase by calpain in cardiomyocytes.

Focal adhesion kinase (FAK) contributes to cellular homeostasis under stress conditions. Here we show that αB-crystallin interacts with and confers protection to FAK against calpain-mediated proteolysis in cardiomyocytes. A hydrophobic patch mapped between helices 1 and 4 of the FAK FAT domain was found to bind to the ß4-ß8 groove of αB-crystallin. Such an interaction requires FAK tyrosine 925 and is enhanced following its phosphorylation by Src, which occurs upon FAK stimulation. αB-crystallin silencing results in calpain-dependent FAK depletion and in the increased apoptosis of cardiomyocytes in response to mechanical stress. FAK overexpression protects cardiomyocytes depleted of αB-crystallin against the stretch-induced apoptosis. Consistently, load-induced apoptosis is blunted in the hearts from cardiac-specific FAK transgenic mice transiently depleted of αB-crystallin by RNA interference. These studies define a role for αB-crystallin in controlling FAK function and cardiomyocyte survival through the prevention of calpain-mediated degradation of FAK.

FERM domain interaction with myosin negatively regulates FAK in cardiomyocyte hypertrophy.

Focal adhesion kinase (FAK) regulates cellular processes that affect several aspects of development and disease. The FAK N-terminal FERM (4.1 protein-ezrin-radixin-moesin homology) domain, a compact clover-leaf structure, binds partner proteins and mediates intramolecular regulatory interactions. Combined chemical cross-linking coupled to MS, small-angle X-ray scattering, computational docking and mutational analyses showed that the FAK FERM domain has a molecular cleft (~998 Å(2)) that interacts with sarcomeric myosin, resulting in FAK inhibition. Accordingly, mutations in a unique short amino acid sequence of the FERM myosin cleft, FP-1, impaired the interaction with myosin and enhanced FAK activity in cardiomyocytes. An FP-1 decoy peptide selectively inhibited myosin interaction and increased FAK activity, promoting cardiomyocyte hypertrophy through activation of the AKT-mammalian target of rapamycin pathway. Our findings uncover an inhibitory interaction between the FAK FERM domain and sarcomeric myosin that presents potential opportunities to modulate the cardiac hypertrophic response through changes in FAK activity.

Expression of laminin-5 γ2 chain in cutaneous pseudocarcinomatous hyperplasia.

BACKGROUND: Since the use of laminin-5 as a marker of invasiveness has been proposed by several authors, our objective was to compare the expression of this protein in pseudocarcinomatous hyperplasia and squamous cell carcinoma (SCC). METHODS: Sixty-four paraffin-embedded skin biopsy samples with diagnosis of epidermal hyperplasia (non-pseudocarcinomatous), pseudocarcinomatous hyperplasia, actinic keratosis/carcinoma in situ, microinvasive and frankly invasive SCC were obtained for immunohistochemical study. RESULTS: Adjacent normal epithelium and epidermal hyperplasia (non-pseudocarcinomatous) showed no staining. In pseudocarcinomatous hyperplasia, laminin-5 was positive, at least focally, in 14 of 16 (87.5%) samples and was concentrated in peripheral cells of elongated rete pegs and in migrating cells in dermis. In samples of microinvasive carcinoma (n = 7), the expression was observed in all cases and was concentrated in the leading edge of the tumor. All cases (n = 21) of frankly invasive SCC showed cells expressing laminin-5, at least focally. Well-differentiated areas of the tumor presented a pattern of expression in peripheral cells of tumor nests while a diffuse pattern of expression was observed in less differentiated areas. CONCLUSION: We showed that cytoplasmic laminin-5 expression should not be used as a criterion of malignancy and is not useful in distinguishing pseudocarcinomatous hyperplasia from microinvasive and well-differentiated SCC.

Shp2 negatively regulates growth in cardiomyocytes by controlling focal adhesion kinase/Src and mTOR pathways.

The aim of this study was to investigate whether Shp2 (Src homology region 2, phosphatase 2) controls focal adhesion kinase (FAK) activity and its trophic actions in cardiomyocytes. We show that low phosphorylation levels of FAK in nonstretched neonatal rat ventricular myocytes (NRVMs) coincided with a relatively high basal association of FAK with Shp2 and Shp2 phosphatase activity. Cyclic stretch (15% above initial length) enhanced FAK phosphorylation at Tyr397 and reduced FAK/Shp2 association and phosphatase activity in anti-Shp2 precipitates. Recombinant Shp2 C-terminal protein tyrosine phosphatase domain (Shp2-PTP) interacted with nonphosphorylated recombinant FAK and dephosphorylated FAK immunoprecipitated from NRVMs. Depletion of Shp2 by specific small interfering RNA increased the phosphorylation of FAK Tyr397, Src Tyr418, AKT Ser473, TSC2 Thr1462, and S6 kinase Thr389 and induced hypertrophy of nonstretched NRVMs. Inhibition of FAK/Src activity by PP2 {4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine} abolished the phosphorylation of AKT, TSC2, and S6 kinase, as well as the hypertrophy of NRVMs induced by Shp2 depletion. Inhibition of mTOR (mammalian target of rapamycin) with rapamycin blunted the hypertrophy in NRVMs depleted of Shp2. NRVMs treated with PP2 or depleted of FAK by specific small interfering RNA were defective in FAK, Src, extracellular signal-regulated kinase, AKT, TSC2, and S6 kinase phosphorylation, as well as in the hypertrophic response to prolonged stretch. The stretch-induced hypertrophy of NRVMs was also prevented by rapamycin. These findings demonstrate that basal Shp2 tyrosine phosphatase activity controls the size of cardiomyocytes by downregulating a pathway that involves FAK/Src and mTOR signaling pathways.

Genetic structure analysis of Eufriesea violacea (Hymenoptera, Apidae) populations from southern Brazilian Atlantic rainforest remnants

Random amplified polymorphic DNA (RAPD) markers were used to analyze the genetic structure of Eufriesea violacea populations in three fragments (85.47, 832.58 and 2800 ha) of Atlantic rainforest located in the north of the Brazilian state of Paraná. A total of twelve primers produced 206 loci, of which 129 were polymorphic (95 percent criterion). The proportions of polymorphic loci in each population ranged from 57.28 percent to 59.2 percent, revealing very similar levels of genetic variability in the groups of bees from each fragment. Unbiased genetic distances between groups ranged from 0.0171 to 0.0284, the smallest genetic distance occurring between bees from the two larger fragments. These results suggest that the E. violacea populations from the three fragments have maintained themselves genetically similar to native populations of this species originally present in northern Paraná.