Antioxidant and anti-Alzheimer's potential of Tetragonisca angustula (Jataí) stingless bee pollen

Alzheimer's disease (AD) is considered the leading cause of dementia in the elderly worldwide. It results in progressive memory loss and impairment of cognitive and motor skills, leading to a high degree of disability and dependence. The development of AD is associated with the accumulation of senile plaques in the brain, caused by the amyloidogenic pathway of the disease. Several genetic and biochemical events are linked to AD development, with oxidative stress being one of them. Due to the scarcity of drugs aimed at treating AD, antioxidant compounds are increasingly studied as therapeutic targets for the disease. In this study, we investigate the antioxidant and anti-Alzheimer potential of the Tetragonisca angustula (Jataí) pollen extract in a Drosophila melanogaster Alzheimer's model. For this purpose, we utilized a D. melanogaster AD-like model, which expresses genes related to the amyloidogenic pathway of Alzheimer's disease. We explored the floral origin of the collected pollen, conducted phytochemical prospecting, and evaluated its antioxidant capacity in vitro. In vivo experiments involved assessing the survival and climbing ability of the D. melanogaster AD-like model with various concentrations of the pollen extract. Our findings revealed that the pollen extract of Tetragonisca angustula exhibits a significant antioxidant response and high concentrations of important phytochemicals, such as flavonoids and polyphenols. Furthermore, it enhanced the survival rate of D. melanogaster, and across all concentrations tested, it improved the climbing ability of the flies after 15 days of treatment with methanolic pollen extract. Additionally, the pollen extract reduced the neurodegeneration index in histopathological analysis. Thus, our study demonstrates the potential of Tetragonisca angustula pollen as an important subject for further investigation, aiming to isolate molecules that could potentially serve as therapeutic targets for Alzheimer's disease.

Identification of potential inhibitors for N-myristoyltransferase (NMT) protein of Plasmodium vivax

Malaria is a neglected parasitic infection of global importance. It is mainly present in tropical countries and caused by a protozoa that belongs to the genus Plasmodium. The disease vectors are female Anopheles mosquitoes infected with the Plasmodium spp. According to the World Health Organization (WHO), there were 241 million malaria cases worldwide in 2020 and approximately 627 thousand malaria deaths in the same year. The increasing resistance to treatment has been a major problem since the beginning of the 21st century. New studies have been conducted to find possible drugs that can be used for the eradication of the disease. In this scenario, a protein named N-myristoyltransferase (NMT) has been studied as a potential drug target. NMT has an important role on the myristoylation of proteins and binds to the plasma membrane, contributing to the stabilization of protein-protein interactions. Thus, inhibition of NMT can lead to death of the parasite cell. Therefore, in order to predict and detect potential inhibitors against Plasmodium NMT, Computer-Aided Drug Design techniques were used in this research that involve virtual screening, molecular docking, and molecular dynamics. Three potential compounds similar to a benzofuran inhibitor were identified as stable PvNMT ligands. These compounds (EXP90, ZBC205 and ZDD968) originate from three different sources, respectively: a commercial library, a natural product library, and the FDA approved drugs dataset. These compounds may be further tested in in vitro and in vivo inhibition tests against Plasmodium vivax NMT.Communicated by Ramaswamy H. Sarma.

Bacteria, yeasts, and fungi associated with larval food of Brazilian native stingless bees

Stingless bees are a diverse group with a relevant role in pollinating native species. Its diet is rich in carbohydrates and proteins, by collecting pollen and nectar supplies the development of its offspring. Fermentation of these products is associated with microorganisms in the colony. However, the composition of microorganisms that comprise this microbiome and its fundamental role in colony development is still unclear. To characterize the colonizing microorganisms of larval food in the brood cells of stingless bees Frieseomelitta varia, Melipona quadrifasciata, Melipona scutellaris, and Tetragonisca angustula, we have utilized molecular and culture-based techniques. Bacteria of the phyla Firmicutes, Proteobacteria, Actinobacteria, and fungi of the phyla Ascomycota, Basidiomycota, Mucoromycota, and Mortierellomycota were found. Diversity analysis showed that F. varia had a greater diversity of bacteria in its microbiota, and T. angustula had a greater diversity of fungi. The isolation technique allowed the identification of 189 bacteria and 75 fungi. In summary, this research showed bacteria and fungi associated with the species F. varia, M. quadrifasciata, M. scutellaris, and T. angustula, which may play an essential role in the survival of these organisms. Besides that, a biobank with bacteria and fungus isolates from LF of Brazilian stingless bees was created, which can be used for different studies and the prospection of biotechnology compounds.

Identification of bioactive peptides from a Brazilian kefir sample, and their anti-Alzheimer potential in Drosophila melanogaster

Alzheimer’s disease (AD) is the most common form of dementia in the elderly, affecting cognitive, intellectual, and motor functions. Different hypotheses explain AD’s mechanism, such as the amyloidogenic hypothesis. Moreover, this disease is multifactorial, and several studies have shown that gut dysbiosis and oxidative stress influence its pathogenesis. Knowing that kefir is a probiotic used in therapies to restore dysbiosis and that the bioactive peptides present in it have antioxidant properties, we explored its biotechnological potential as a source of molecules capable of modulating the amyloidogenic pathway and reducing oxidative stress, contributing to the treatment of AD. For that, we used Drosophila melanogaster model for AD (AD-like flies). Identification of bioactive peptides in the kefir sample was made by proteomic and peptidomic analyses, followed by in vitro evaluation of antioxidant and acetylcholinesterase inhibition potential. Flies were treated and their motor performance, brain morphology, and oxidative stress evaluated. Finally, we performed molecular docking between the peptides found and the main pathology-related proteins in the flies. The results showed that the fraction with the higher peptide concentration was positive for the parameters evaluated. In conclusion, these results revealed these kefir peptide-rich fractions have therapeutic potential for AD.

Rat postnatal prostate development is impaired by in vitro high-glucose environment

The prostate development has an important postnatal period where cell proliferation begins at the first days after birth and is related to gland growth and ramification. Any metabolic and/or hormonal changes occurring during the postnatal period can interfere with prostate branching. Hyperglycemia is a common condition in low-weight preterm babies at neonatal period and also a disorder found in the offspring of obese mothers. Thus, this study aimed to investigate the in vitro effects of a glucose-rich environment during prostate postnatal development. Wistar rats prostate were removed at birth and cultured for 1, 2 and 3 days in DMEM under normal (5.5 mM) or elevated (7 and 25 mM) glucose concentrations. Samples were processed for morphological analysis, PCNA and smooth muscle α-actin immunohistochemistry, evaluation of active caspase-3, ERK1/2 and Wnt5a gene expression. High glucose concentrations reduced the number of prostatic buds and proliferating cells. The natural increase in smooth muscle cells and collagen deposition observed in control prostates during the first 3 days of development was reduced by elevated glucose concentrations. The amount of active caspase-3 was higher in prostates incubated at 7 mM and TGF-β levels also increased sharply after both glucose concentrations. Additionally, high glucose environment decreased ERK 1/2 activation and increased Wnt5a expression. These data show that high levels of glucose during the first postnatal days affected prostate development by inhibiting cell proliferation which impairs bud branching and this was associated with anti-proliferative signals such as decreased ERK1/2 activation and increased Wnt5a expression.

TNF-mimetic peptide mixed with fibrin glue improves peripheral nerve regeneration

Surgical intervention is necessary following nerve trauma. Tubular prostheses can guide growing axons and inserting substances within these prostheses can be positive for the regeneration, making it an alternative for the current standard tools for nerve repair. Our aim was to investigate the effects of fibrin glue BthTL when combined with a synthetic TNF mimetic-action peptide on nerve regeneration. Male Wistar rats suffered left sciatic nerve transection. For repairing, we used empty silicon tubes (n = 10), tubes filled with fibrin glue BthTL (Tube + Glue group, n = 10) or tubes filled with fibrin glue BThTL mixed with TNF mimetic peptide (Tube + Glue + Pep group, n = 10). Animals were euthanized after 45 days. We collected nerves to perform immunostaining (neurofilament, GAP43, S100-β, NGFRp75 and Iba-1), light and transmission electron microscopy (for counting myelinated, unmyelinated and degenerated fibers; and for the evaluation of morphometric aspects of regenerated fibers) and collagen staining. All procedures were approved by local ethics committee (protocol 063/17). Tube + Glue + Pep group showed intense inflammatory infiltrate, higher Iba-1 expression, increased immunostaining for NGFRp75 receptor (which characterizes Schwann cell regenerative phenotype), higher myelin thickness and fiber diameter and more type III collagen deposition. Tube + Glue group showed intermediate results between empty tube and Tube + Glue + Pep groups for anti-NGFRp75 immunostaining, inflammation and collagen; on fiber counts, this group showed more degenerate fibers and fewer unmyelinated axons than others. Empty tube group showed superiority only in GAP43 immunostaining. A combination of BthTL glue and TNF mimetic peptide induced greater axonal regrowth and remyelination.

Kefir metabolites in a fly model for Alzheimer's disease

Alzheimer's Disease (AD) is the most common cause of dementia among elderly individuals worldwide, leading to a strong motor-cognitive decline and consequent emotional distress and codependence. It is traditionally characterized by amyloidogenic pathway formation of senile plaques, and recent studies indicate that dysbiosis is also an important factor in AD's pathology. To overcome dysbiosis, probiotics-as kefir-have shown to be a great therapeutic alternative for Alzheimer's disease. In this present work, we explored kefir as a probiotic and a metabolite source as a modulator of microbiome and amyloidogenic pathway, using a Drosophila melanogaster model for AD (AD-like flies). Kefir microbiota composition was determined through 16S rRNA sequencing, and the metabolome of each fraction (hexane, dichloromethane, ethyl acetate, and n-butanol) was investigated. After treatment, flies had their survival, climbing ability, and vacuolar lesions accessed. Kefir and fraction treated flies improved their climbing ability survival rate and neurodegeneration index. In conclusion, we show that kefir in natura, as well as its fractions may be promising therapeutic source against AD, modulating amyloidogenic related pathways.

Reducing toxicity and antimicrobial activity of a pesticide mixture via photo-Fenton in different aqueous matrices using iron complexes

This is the first study to investigate ethylenediamine-N,N'-disuccinic acid (EDDS)/photo-Fenton process to polish real wastewater containing pesticides for possible water reuse. To this end, simultaneous degradation of pesticides ametrine, atrazine, imidacloprid and tebuthiuron was evaluated in distilled water (DW) and in sewage treatment plant (STP) effluent at initial pH 6.0. Several operational parameters (Fe³⁺-EDDS concentration, Fe³⁺-EDDS molar ratio, EDDS addition patterns and radiation source) were evaluated. 80-98% removal of target pesticides were obtained in DW using 30 μmol L^-1 of Fe³⁺-EDDS with a molar ratio of 1:2 (300 μmol L^-1 of H₂O₂). In addition, the proposed Fe³⁺-EDDS photo-Fenton at pH 6 was more efficient than classic photo-Fenton at pH 2.7 (30-84% removal). Experiments conducted in the presence of radical trapping agents (2-propanol or chloroform) revealed that HO^• was the most active radical during treatment. Matrix composition strongly affected the degradation of target pesticides as a six-fold higher concentration of reagents (180 μmol L^-1 of Fe³⁺-EDDS and 1800 μmol L^-1 of H₂O₂) was needed to reach the same efficiency in STP compared to DW. Even so, first order rate constants corresponding to the degradation of pesticides in DW (k = 0.098-0.85 min^-1) were nearly two-fold higher than in STP (k = 0.079-0.49 min^-1) under the same radiation source (black-light or solar radiation). Finally, acute toxicity towards Vibrio fischeri and Drosophila melanogaster flies, and antibacterial activity assessed for Escherichia coli were eliminated after the application of the proposed treatment, thus indicating environmental safety for either discharge or reuse of treated wastewater for crop irrigation in agriculture.

Degradation mechanism of fipronil and its transformation products, matrix effects and toxicity during the solar/photo-Fenton process using ferric citrate complex

This study presents the degradation of fipronil in sewage treatment plant (STP) effluent by photo-Fenton at near neutral pH (pH 6.0) using Fe³⁺/Citrate complex. 83% of fipronil degradation was reached using a molar iron/citrate ratio of 1:3 (192 μmol L^-1 of Fe³⁺/576 μmol L^-1 of citrate). Photo-Fenton reduced the toxicity of treated solutions as according to the survival of Drosophila melanogaster exposed to non-treated and treated samples. Control experiments performed in distilled water using 32 μmol L^-1 of Fe³⁺/96 μmol L^-1 of citrate achieved 98% of fipronil degradation within 100 kJ m^-2 (UV-A radiation, k = 30 × 10^-3 kJ^-1 m² and t_1/2 = 23 kJ m^-2), thus indicating that fipronil degradation is impaired by natural organic matter and inorganic ions present in STP effluent. Degradation was faster under solar radiation, as the same efficiency (98%) was obtained after 75 kJ m^-2 (k = 63 × 10^-3 kJ^-1 m² and t_1/2 = 11 kJ m^-2). In addition, pathways of fipronil degradation using Fe³⁺/Citrate under solar and UV-A radiation were investigated and transformation products proposed. Results revealed that the HO^• attack occurred preferentially in the pyrazole ring. Eight transformation products were identified by UHPLC-Q-TOF-MS and four are unprecedented in the literature. Control experiments in distilled water demonstrated that toxicity reduction is related to fipronil degradation and that transformation products are less toxic than fipronil. Furthermore, toxicity of STP fortified with fipronil was reduced after photo-Fenton. These results demonstrate the feasibility of applying this process using Fe³⁺/Citrate complex for fipronil degradation in a real matrix.

Soluble epoxide hydrolase inhibitor, TPPU, increases regulatory T cells pathway in an arthritis model

Epoxyeicosatrienoic acids (EET) and related epoxy fatty acids (EpFA) are endogenous anti‐inflammatory compounds, which are converted by the soluble epoxide hydrolase (sEH) to dihydroxylethersatrienoic acids (DHETs) with lessened biological effects. Inhibition of sEH is used as a strategy to increase EET levels leading to lower inflammation. Rheumatoid arthritis is a chronic autoimmune disease that leads to destruction of joint tissues. This pathogenesis involves a complex interplay between the immune system, and environmental factors. Here, we investigate the effects of inhibiting sEH with 1‐trifluoromethoxyphenyl‐3‐(1‐propionylpiperidin‐4‐yl) urea (TPPU) on a collagen‐induced arthritis model. The treatment with TPPU ameliorates hyperalgesia, edema, and decreases the expression of important pro‐inflammatory cytokines of Th1 and Th17 profiles, while increasing Treg cells. Considering the challenges to control RA, this study provides robust data supporting that inhibition of the sEH is a promising target to treat arthritis.

Deep sequencing analysis of toad Rhinella schneideri skin glands and partial biochemical characterization of its cutaneous secretion

Background

Animal poisons and venoms are sources of biomolecules naturally selected. Rhinella schneideri toads are widespread in the whole Brazilian territory and they have poison glands and mucous gland. Recently, protein from toads’ secretion has gaining attention. Frog skin is widely known to present great number of host defense peptides and we hypothesize toads present them as well. In this study, we used a RNA-seq analysis from R. schneideri skin and biochemical tests with the gland secretion to unravel its protein molecules.

Methods

Total RNA from the toad skin was extracted using TRizol reagent, sequenced in duplicate using Illumina Hiseq2500 in paired end analysis. The raw reads were trimmed and de novo assembled using Trinity. The resulting sequences were submitted to functional annotation against non-redundant NCBI database and Database of Anuran Defense Peptide. Furthermore, we performed caseinolytic activity test to assess the presence of serine and metalloproteases in skin secretion and it was fractionated by fast liquid protein chromatography using a reverse-phase column. The fractions were partially sequenced by Edman’s degradation.

Results

We were able to identify several classes of antimicrobial peptides, such as buforins, peroniins and brevinins, as well as PLA₂, lectins and galectins, combining protein sequencing and RNA-seq analysis for the first time. In addition, we could isolate a PLA₂ from the skin secretion and infer the presence of serine proteases in cutaneous secretion.

Conclusions

We identified novel toxins and proteins from R. schneideri mucous glands. Besides, this is a pioneer study that presented the in depth characterization of protein molecules richness from this toad secretion. The results obtained herein showed evidence of novel AMP and enzymes that need to be further explored.

Electronic supplementary material

The online version of this article (10.1186/s40409-018-0173-8) contains supplementary material, which is available to authorized users.

In-Depth Venome of the Brazilian Rattlesnake Crotalus durissus terrificus: An Integrative Approach Combining Its Venom Gland Transcriptome and Venom Proteome

Snake venoms are complex mixtures mainly composed of proteins and small peptides. Crotoxin is one of the most studied components from Crotalus venoms, but many other components are less known due to their low abundance. The venome of Crotalus durissus terrificus, the most lethal Brazilian snake, was investigated by combining its venom gland transcriptome and proteome to create a holistic database of venom compounds unraveling novel toxins. We constructed a cDNA library from C. d. terrificus venom gland using the Illumina platform and investigated its venom proteome through high resolution liquid chromotography-tandem mass spectrometry. After integrating data from both data sets, more than 30 venom components classes were identified by the transcriptomic analysis and 15 of them were detected in the venom proteome. However, few of them (PLA₂, SVMP, SVSP, and VEGF) were relatively abundant. Furthermore, only seven expressed transcripts contributed to ∼82% and ∼73% of the abundance in the transcriptome and proteome, respectively. Additionally, novel venom proteins are reported, and we highlight the importance of using different databases to perform the data integration and discuss the structure of the venom components-related transcripts identified. Concluding, this research paves the way for novel investigations and discovery of future pharmacological agents or targets in the antivenom therapy.

Salmonella Gallinarum field isolates and its relationship to vaccine strain SG9R

1. The aim of the present study was to determine if the 9R-strain of the Salmonella Gallinarum live vaccine was responsible for having fowl typhoid outbreaks in chicken flocks from both chicken and turkey breeders as well as to verify the antimicrobial resistance of the isolates from the outbreaks. 2. The triplex polymerase chain reaction, standard antimicrobial test, beta-lactamase genes identification and Ion Torrent PMG whole-genome sequence were used in the field isolates and in the vaccine strain of S. Gallinarum. 3. The 60 tested isolates were not from vaccine origin and manifested high resistance to drugs from macrolide and quinolone groups. Whole-genome sequencing (WGS) and single nucleotide polymorphism analysis on selected isolates for core genes from Salmonella enterica confirmed the wild origin of these isolates and showed two possible sources of S. Gallinarum in the studied outbreaks. 4. S. Gallinarum isolated from fowl typhoid outbreaks in the studied period were not caused by the use of the SG9R live vaccine. The source of strains sequenced was diverse.

Peptide-based electrochemical biosensor for juvenile idiopathic arthritis detection

Juvenile idiopathic arthritis (JIA) is a wide group of diseases, characterized by synovial inflammation and joint tissue damage. Due to the delay in the implementation of biomarkers into clinical practice and the association with severe sequels, there is an imperative need for new JIA diagnosis strategies. Electrochemical biosensors based on screen-printed electrodes and peptides are promising alternatives for molecular diagnosis. In this work, a novel biosensor for detecting juvenile idiopathic arthritis (JIA) was developed based on the immobilization of the PRF+1 mimetic peptide, as recognition biological element, on the surface of screen-printed carbon electrode. This biosensor was able to discriminate the JIA positive and negative serum samples from different individuals using differential pulse voltammetry, presenting limits of detection and quantification in diluted samples of 1:784 (v/v) and 1:235 (v/v), respectively. Evaluation by electrochemical impedance spectroscopy showed R_CT 3 times higher for JIA positive sample than for a pool of human serum samples from healthy individuals. Surface analysis of the biosensor by atomic force microscopy, after contact with JIA positive serum, presented great globular clusters irregularly distributed. The long-term stability of the biosensor was evaluated, remaining functional for over 40 days of storage (after storage at 8°C). Therefore, a simple, miniaturized and selective biosensor was developed, being the first one based on mimetic peptide and screen-printed carbon electrode, aiming at the diagnosis of the juvenile idiopathic arthritis in real serum samples.

Heterologous expression of abaecin peptide from Apis mellifera in Pichia pastoris

Background

Antimicrobial peptides (AMPs) are the first line of host immune defense against pathogens. Among AMPs from the honeybee Apis mellifera, abaecin is a major broad-spectrum antibacterial proline-enriched cationic peptide.

Results

For heterologous expression of abaecin in Pichia pastoris, we designed an ORF with HisTag, and the codon usage was optimized. The gene was chemically synthetized and cloned in the pUC57 vector. The new ORF was sub-cloned in the pPIC9 expression vector and transformed into P. pastoris. After selection of positive clones, the expression was induced by methanol. The supernatant was analyzed at different times to determine the optimal time for the recombinant peptide expression. As a proof-of-concept, Escherichia coli was co-incubated with the recombinant peptide to verify its antimicrobial potential.

Discussion

Briefly, the recombinant Abaecin (rAbaecin) has efficiently decreased E. coli growth (P < 0.05) through an in vitro assay, and may be considered as a novel therapeutic agent that may complement other conventional antibiotic therapies.

Characterization of antennal sensilla, larvae morphology and olfactory genes of Melipona scutellaris stingless bee

There is growing evidence in the literature suggesting that caste differentiation in the stingless bee, Melipona scutellaris, and other bees in the genus Melipona, is triggered by environmental signals, particularly a primer pheromone. With the proper amount of food and a chemical stimulus, 25% of females emerge as queens, in agreement with a long-standing “two loci/two alleles model” proposed in the 1950s. We surmised that these larvae must be equipped with an olfactory system for reception of these chemical signals. Here we describe for the first time the diversity of antennal sensilla in adults and the morphology of larvae of M. scutellaris. Having found evidence for putative olfactory sensilla in larvae, we next asked whether olfactory proteins were expressed in larvae. Since the molecular basis of M. scutellaris is still unknown, we cloned olfactory genes encoding chemosensory proteins (CSP) and odorant-binding proteins (OBPs) using M. scutellaris cDNA template and primers designed on the basis CSPs and OBPs previously reported from the European honeybee, Apis mellifera. We cloned two CSP and two OBP genes and then attempted to express the proteins encoded by these genes. With a recombinant OBP, MscuOBP8, and a combinatorial single-chain variable fragment antibody library, we generated anti-MscuOBP8 monoclonal antibody. By immunohistochemistry we demonstrated that the anti-MscuOBP8 binds specifically to the MscuOBP8. Next, we found evidence that MscuOBP8 is expressed in M. scutellaris larvae and it is located in the mandibular region, thus further supporting the hypothesis of olfactory function in immature stages. Lastly, molecular modeling suggests that MscuOBP8 may function as a carrier of primer pheromones or other ligands.

Soluble Epoxide Hydrolase Pharmacological Inhibition Decreases Alveolar Bone Loss by Modulating Host Inflammatory Response, RANK-Related Signaling, Endoplasmic Reticulum Stress, and Apoptosis

Epoxyeicosatrienoic acids (EETs), metabolites of arachidonic acid derived from the cytochrome P450 enzymes, are mainly metabolized by soluble epoxide hydrolase (sEH) to their corresponding diols. EETs but not their diols, have anti-inflammatory properties, and inhibition of sEH might provide protective effects against inflammatory bone loss. Thus, in the present study, we tested the selective sEH inhibitor, 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), in a mouse model of periodontitis induced by infection with Aggregatibacter actinomycetemcomitans Oral treatment of wild-type mice with TPPU and sEH knockout (KO) animals showed reduced bone loss induced by A. actinomycetemcomitans This was associated with decreased expression of key osteoclastogenic molecules, receptor activator of nuclear factor-κB/RANK ligand/osteoprotegerin, and the chemokine monocyte chemotactic protein 1 in the gingival tissue without affecting bacterial counts. In addition, downstream kinases p38 and c-Jun N-terminal kinase known to be activated in response to inflammatory signals were abrogated after TPPU treatment or in sEH KO mice. Moreover, endoplasmic reticulum stress was elevated in periodontal disease but was abrogated after TPPU treatment and in sEH knockout mice. Together, these results demonstrated that sEH pharmacological inhibition may be of therapeutic value in periodontitis.

Epigenetic modifications and their relation to caste and sex determination and adult division of labor in the stingless bee Melipona scutellaris

Stingless bees of the genus Melipona, have long been considered an enigmatic case among social insects for their mode of caste determination, where in addition to larval food type and quantity, the genotype also has a saying, as proposed over 50 years ago by Warwick E. Kerr. Several attempts have since tried to test his Mendelian two-loci/two-alleles segregation hypothesis, but only recently a single gene crucial for sex determination in bees was evidenced to be sex-specifically spliced and also caste-specifically expressed in a Melipona species. Since alternative splicing is frequently associated with epigenetic marks, and the epigenetic status plays a major role in setting the caste phenotype in the honey bee, we investigated here epigenetic chromatin modification in the stingless bee Melipona scutellaris. We used an ELISA-based methodology to quantify global methylation status and western blot assays to reveal histone modifications. The results evidenced DNA methylation/demethylation events in larvae and pupae, and significant differences in histone methylation and phosphorylation between newly emerged adult queens and workers. The epigenetic dynamics seen in this stingless bee species represent a new facet in the caste determination process in Melipona bees and suggest a possible mechanism that is likely to link a genotype component to the larval diet and adult social behavior of these bees.

Association between pro-inflammatory cytokine interleukin-33 and periodontal disease in the elderly: A retrospective study

Background:

Senescence is a multifactorial process that in humans may be accompanied by inflammation and immune dysfunction in the oral cavity. Notably, periodontal disease, considered one of the most common inflammatory disorders in the oral cavity, has also been linked to the onset of other chronic inflammatory diseases common in the elderly. Thus, investigating immunity and inflammation during senescence may not only illuminate the pathophysiology of periodontal disease, but also identify new therapeutic targets.

Materials and Methods:

To this end, we retrospectively and systematically reviewed studies of immune molecules associated with periodontal disease. These studies were identified in PubMed from three independent searches based on distinct sets of search terms.

Results:

The data highlight the need to further investigate inflammatory molecules involved in chronic periodontal disease in the elderly, but strongly suggest that interleukin (IL)-33 is involved. Indeed, various genetic and environmental factors appear to contribute to pathogenesis via IL-33.

Conclusion:

The IL-33 axis may be promising therapeutic target in elderly patients.

Antibiotic Resistance of Bacteria Involved in Urinary Infections in Brazil: A Cross-Sectional and Retrospective Study

Empirical and prolonged antimicrobial treatment of urinary tract infections caused by Escherichia coli is associated with the emergence of bacterial resistance, and not all countries have strict policies against the indiscriminate use of drugs in order to prevent resistance. This cross-sectional and retrospective study (2010–2015) aimed to evaluate the sensitivity and resistance of patient-derived E. coli to different drugs broadly used to treat urinary infections in Brazil: ampicillin + sulbactam, cephalothin, ciprofloxacin, norfloxacin, and nitrofurantoin. We obtained 1654 E. coli samples from ambulatory patients with disease symptoms of the urinary tract from a Brazilian public hospital. While all antibiotics were effective in killing E. coli to a large degree, nitrofurantoin was the most effective, with fewer samples exhibiting antibiotic resistance. We assessed the costs of generic and brand name versions of each antibiotic. Nitrofurantoin, the most effective antibiotic, was the cheapest, followed by the fluoroquinolones (ciprofloxacin and norfloxacin), ampicillin + sulbactam and, lastly, cephalothin. Finally, assessment of antibiotic resistance to fluoroquinolones over the study period and extrapolation of the data led to the conclusion that these antibiotics could no longer be effective against E. coli-based urinary infections in approximately 20 years if their indiscriminate use in empirical treatment continues.

Chromosomal disruption and rearrangements during murine sarcoma development converge to stable karyotypic formation kept by telomerase overexpression

BACKGROUND

Tumor initiation presents a complex and unstable genomic landscape; one of the earliest hallmark events of cancer, and its progression is probably based on selection mechanisms under specific environments that lead to functional tumor cell speciation. We hypothesized that viable tumor phenotypes possess common and highly stable karyotypes and their proliferation is facilitated by an attuned high telomerase activity. Very few investigations have focused on the evolution of common chromosomal rearrangements associated to molecular events that result in functional phenotypes during tumor development.

RESULTS

We have used cytogenetic, flow cytometry and cell culture tools to investigate chromosomal rearrangements and clonality during cancer development using the murine sarcoma TG180 model, and also molecular biology techniques to establish a correlation between chromosome instability and telomerase activity, since telomeres are highly affected during cancer evolution. Cytogenetic analysis showed a near-tetraploid karyotype originated by endoreduplication. Chromosomal rearrangements were random events in response to in vitro conditions, but a stable karyotypic equilibrium was achieved during tumor progression in different in vivo conditions, suggesting that a specific microenvironment may stabilize the chromosomal number and architecture. Specific chromosome aberrations (marker chromosomes) and activated regions (rDNAs) were ubiquitous in the karyotype, suggesting that the conservation of these patterns may be advantageous for tumor progression. High telomerase expression was also correlated with the chromosomal rearrangements stabilization.

CONCLUSIONS

Our data reinforce the notion that the sarcoma cell evolution converges from a highly unstable karyotype to relatively stable and functional chromosome rearrangements, which are further enabled by telomerase overexpression.

A novel reactive epitope-based antigen targeted by serum autoantibodies in oligoarticular and polyarticular juvenile idiopathic arthritis and development of an electrochemical biosensor

Currently, there are no specific markers for juvenile idiopathic arthritis (JIA) diagnosis, which is based on clinical symptoms and some blood tests for diseases' exclusion. Aiming to select new epitope-based antigens (mimotopes) that could recognize circulating autoantibodies in most JIA forms, we screened a phage displayed random peptide library against IgG antibodies purified from serum of JIA patients. ELISA assay was carried out to confirm immunoreactivity of selected peptides against sera IgG antibodies from JIA patients, healthy children and patients with other autoimmune diseases. The mimotope PRF+1 fused to phage particles was able to efficiently discriminate JIA patients from controls, and for this reason was chosen to be chemically synthesized for validation in a larger sample size. The synthetic peptide was immobilized onto bioelectrodes' surface for antibody detection by electrochemical analyses through differential pulse voltammetry. The PRF+1 synthetic peptide has efficiently discriminated JIA patients from control groups (p<0.0001) with a very good accuracy (AUC>0.84; sensitivity=61%; specificity=91%). The electrochemical platform proved to be fast, low cost and effective in detecting anti-PRF+1 antibodies from JIA patients compared to healthy controls (p=0.0049). Our study describes a novel and promising epitope-based biomarker for JIA diagnosis that can become a useful tool for screening tests, which was successfully incorporated onto an electrochemical biosensor and could be promptly used in field diagnostics.

A Short Peptide That Mimics the Binding Domain of TGF-β1 Presents Potent Anti-Inflammatory Activity

The transforming growth factor beta 1 (TGF-β1) is a pleiotropic cytokine with multiple roles in development, wound healing, and immune regulation. TGF-β1-mediated immune dysfunction may lead to pathological conditions, such as inflammation. Chronic inflammatory process is characterized by a continuous release of pro-inflammatory cytokines, and the inhibition or the blockage of these cytokines signaling pathways are considered a target treatment. In this context, despite the high numbers of TGF-β-targeted pathways, the inducible regulatory T cells (iTreg) to control inflammation seems to be a promising approach. Our aim was to develop novel peptides through phage display (PhD) technology that could mimic TGF-β1 function with higher potency. Specific mimetic peptides were obtained through a PhD subtraction strategy from whole cell binding using TGF-β1 recombinant as a competitor during elution step. We have selected a peptide that seems to play an important role on cellular differentiation and modulation of TNF-α and IL-10 cytokines. The synthetic pm26TGF-β1 peptide tested in PBMC significantly down-modulated TNF-α and up-regulated IL-10 responses, leading to regulatory T cells (Treg) phenotype differentiation. Furthermore, the synthetic peptide was able to decrease leukocytes rolling in BALB/C mice and neutrophils migration during inflammatory process in C57BL/6 mice. These data suggest that this peptide may be useful for the treatment of inflammatory diseases, especially because it displays potent anti-inflammatory properties and do not exhibit neutrophils’ chemoattraction.

Improved serological detection of rheumatoid arthritis: a highly antigenic mimotope of carbonic anhydrase III selected in a murine model by phage display

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects around 1% of the human population worldwide. RA diagnosis can be difficult as there is no definitive test for its detection. Therefore, the aim of this study was to identify biomarkers that could be used for RA diagnosis.

METHODS

Sera from a collagen-induced arthritis mouse model were used to select potential biomarkers for RA diagnosis by phage display technology. In silico and in vitro analyses were performed to characterize and validate the selected peptides. Samples were classified into three groups: RA; two other immune-mediated rheumatic diseases (systemic lupus erythematosus (SLE) and ankylosing spondylitis (AS)); and healthy controls (HC). Enzyme-linked immunosorbent assay (ELISA) was carried out to determine antibody levels, and diagnostic parameters were determined by constructing receiver operating characteristic curves. Mass spectrometry and Western blot were performed to identify the putative autoantigen that was mimicked by a highly reactive mimotope.

RESULTS

After three rounds of selection, 14 clones were obtained and tested for immunoreactivity analysis against sera from RA and HC groups. The phage-fused peptide with the highest immunoreactivity (M12) was synthesized, and was able to efficiently discriminate RA patients from SLE, AS and HCs (p < 0.0001) by ELISA. The specificity and sensitivity of anti-M12 antibodies for RA diagnosis were 91 % and 84.3 %, respectively. The M12 peptide was identified as one that mimics a predicted antigenic site of the carbonic anhydrase III (CAIII) protein, a ubiquitous biomarker that has been identified in patients with other diseases.

CONCLUSION

M12 is the first peptide associated with the CAIII protein that may be used as an antigen for antibody detection to aid in RA diagnosis with high sensitivity and specificity.

Anti-type II collagen antibodies detection and avidity in patients with oligoarticular and polyarticular forms of juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) refers to a heterogeneous group of illnesses that have in common the occurrence of chronic joint inflammation in children younger than 16 years of age. The diagnosis is made only on clinical assessment. The identification of antibody markers could improve the early diagnosis, optimizing the clinical management of patients. Type II collagen is one potential autoantigen that has been implicated in the process of arthritis development. The aims of our study were to investigate the occurrence of anti-type II collagen antibodies and also to determine the avidity of the antibody-antigen binding. Ninety-six patients with oligoarticular or polyarticular JIA, 13 patients with ankylosing spondylitis (AS) and 61 healthy controls (HC) were tested for anti-type II collagen antibodies by ELISA and avidity ELISA. Sensitivity and specificity were determined by the receiver operating characteristic (ROC) curve analysis. Forty-two JIA patients (44%) were positive for antibodies against type II collagen. Its detection was significantly higher in JIA patients than in AS patients (p=0.006) and HCs (p<0.0001). Furthermore, anti-type II collagen antibody detection was significantly more frequent in patients with JIA of ≤6 months duration (p=0.0007). Antibodies displaying high avidity to type II collagen were associated with disease activity (p=0.004). This study demonstrates that antibodies against type II collagen are present in the serum of patients with oligoarticular and polyarticular JIA, being its presence more prevalent in patients with early disease. It also demonstrates that JIA patients with active disease present antibodies with high avidity against type II collagen.

Complete mitochondrial genome sequence of Melipona scutellaris, a Brazilian stingless bee

Melipona scutellaris is a Brazilian stingless bee species and a highly important native pollinator besides its use in rational rearing for honey production. In this study, we present the whole mitochondrial DNA sequence of M. scutellaris from a haploid male. The mitogenome has a size of 14,862 bp and harbors 13 protein-coding genes (PCGs), 2 rRNA genes and 21 tRNA genes.

Isolation, in vitro propagation, genetic analysis, and immunogenic characterization of an Ehrlichia canis strain from southeastern Brazil

Amplification of the 16S rRNA gene from a blood sample obtained from a dog in southeastern Brazil was used to confirm a naturally acquired Ehrlichia (E.) canis infection. Following isolation and culturing of the new bacterial strain called Uberlândia, partial sequences of the dsb and p28 genes were obtained. The dsb partial sequence of the novel strain was 100% similar to dsb gene sequences of E. canis obtained from different geographic areas around the world. Conversely, the p28 partial sequence for the E. canis Uberlândia strain differed at several nucleotides from other sequences available in GenBank. To confirm the antigenic profile of the Uberlândia strain, an indirect immunofluorescence assay against E. canis antigens was performed using dog sera collected from two different areas in Brazil (Uberlândia and São Paulo). The results suggest that both antigens were able to identify animals seropositive for E. canis in Brazil since these Brazilian strains appear to be highly conserved.

A novel highly reactive Fab antibody for breast cancer tissue diagnostics and staging also discriminates a subset of good prognostic triple-negative breast cancers

The discovery of novel markers for breast cancer (BC) has been recently relied on antibody combinatorial libraries and selection through phage display. We constructed a recombinant Fab library, and after selections against BC tissues, the FabC4 clone was thoroughly investigated by immunohistochemistry in 232 patients with long-term follow-up. The FabC4 ligand was determined by mass spectrometry. The FabC4 expression was associated with younger age, lack of progesterone receptor, higher histological grades and non-luminal subtypes, and it also identified a subset of good prognostic triple-negative BCs, possibly targeting a conformational epitope of Cytokeratin-10 (CK10). This new CK10-epitope specific antibody may open new possibilities in diagnostic and therapeutic strategies.

Insights into the Melipona scutellaris (Hymenoptera, Apidae, Meliponini) fat body transcriptome

The insect fat body is a multifunctional organ analogous to the vertebrate liver. The fat body is involved in the metabolism of juvenile hormone, regulation of environmental stress, production of immunity regulator-like proteins in cells and protein storage. However, very little is known about the molecular mechanisms involved in fat body physiology in stingless bees. In this study, we analyzed the transcriptome of the fat body from the stingless bee Melipona scutellaris. In silico analysis of a set of cDNA library sequences yielded 1728 expressed sequence tags (ESTs) and 997 high-quality sequences that were assembled into 29 contigs and 117 singlets. The BLAST X tool showed that 86% of the ESTs shared similarity with Apis mellifera (honeybee) genes. The M. scutellaris fat body ESTs encoded proteins with roles in numerous physiological processes, including anti-oxidation, phosphorylation, metabolism, detoxification, transmembrane transport, intracellular transport, cell proliferation, protein hydrolysis and protein synthesis. This is the first report to describe a transcriptomic analysis of specific organs of M. scutellaris. Our findings provide new insights into the physiological role of the fat body in stingless bees.

Cobalt chloride induces metaphase when topically applied to larvae and pupae of the stingless bee Melipona scutellaris (Hymenoptera, Apidae, Meliponini)

In order to optimize preparations of bee metaphases, we tested cobalt chloride, which has been used as a metaphase inducer in other organisms, such as hamsters and fish. Four microliters of 65 mM cobalt chloride aqueous solution was topically applied to larval and pupal stages of the stingless bee Melipona scutellaris. The cerebral ganglion was removed after treatment and prepared for cytogenetic analysis. Identically manipulated untreated individuals were used as controls. The number of metaphases was increased 3-fold in treated individuals compared to controls. The micronucleus test showed no mutagenic effects of cobalt chloride on M. scutellaris cells. We concluded that cobalt chloride is a metaphase-inducing agent in M. scutellaris, thus being useful for cytogenetic analyses.

Characterization of DNA polymorphisms in Caryocar brasiliense in populations with and without thorn at the endocarp by RAPD markers

Caryocar brasiliense (pequi), is one of the main species at the biome of the Brazilian savannah due to its use in culinary, popular medicine, industry in general, and iron and steel industry. At São José do Xingu (MT), a tree of C. brasiliense without thorn at the endocarp was found, which enables the improvement of C. brasiliense not only for consumption but also to the high appreciation it already has. To detect the existing differences between the pequi with and without the thorn at the endocarp, RADP markers were used. The generated polymorphisms were cloned and sequenced in order to identify the sequences that are responsible for the fenotypical alteration. It was observed that the pequi without thorn is genetically isolated from the other populations of pequi with thorn at the endocarp, proving that this characteristic is related to the genetic divergence of the species. Analysis in BLASTn evidenced the similarity of the Dof1 genes of Zea mays to its gene of phosphinotricin acetyl transferase. In the analysis of BLASTx, the similarity was verified to the proteins responsible for the deficiency in ferric reductase 4, and catalase.

Isolation and functional characterization of proinflammatory acidic phospholipase A2 from Bothrops leucurus snake venom

In the present study, an acidic PLA(2), designated Bl-PLA(2), was isolated from Bothrops leucurus snake venom through two chromatographic steps: ion-exchange on CM-Sepharose and hydrophobic chromatography on Phenyl-Sepharose. Bl-PLA(2) was homogeneous on SDS-PAGE and when submitted to 2D electrophoresis the molecular mass was 15,000Da and pI was 5.4. Its N-terminal sequence revealed a high homology with other Asp49 acidic PLA(2)s from snake venoms. Its specific activity was 159.9U/mg and the indirect hemolytic activity was also higher than that of the crude venom. Bl-PLA(2) induced low myotoxic and edema activities as compared to those of the crude venom. Moreover, the enzyme was able to induce increments in IL-12p40, TNF-α, IL-1β and IL-6 levels and no variation of IL-8 and IL-10 in human PBMC stimulated in vitro, suggesting that Bl-PLA(2) induces proinflammatory cytokine production by human mononuclear cells. Bothrops leucurus venom is still not extensively explored and knowledge of its components will contribute for a better understanding of its action mechanism.

Specific phage-displayed peptides discriminate different forms of neurocysticercosis by antibody detection in the serum samples

Neurocysticercosis (NC), caused by Taenia solium metacestode, infects the central nervous system and is a devastating parasitic infection. Diagnosis is based on symptoms, imaging, serology and epidemiology. Current markers present variable sensitivity and specificity, frequent cross-reactions and are not able to discriminate NC clinical forms. The aim of this study was to select mimotopes of T. solium metacestode antigens that may be used in NC immunodiagnosis, specifically to discriminate between active and inactive forms. A random peptide phage display library was screened against IgY from chickens immunized with total saline extract from T. solium metacestodes and validated against 110 serum samples, classified into active NC (18), inactive NC (22), cross-reactive parasitic diseases (40) and healthy controls (30). We have successfully selected seven peptides with significant immunoreactivity to IgG of NC patients, with sensitivity ranging from 95.5% to 100% to detect the inactive form and specificity varied from 85.7% to 94.3%. One phage-displayed peptide (Cc48) can be directly used as biomarker to distinguish inactive from active forms with an accuracy of 95.7%, and this novel mimotope may also be used as an auxiliary tool to neuroimaging tests and treatment follow-up.