Oleuropein Protects Against Cerebral Ischemia Injury in Rats: Molecular Docking,Biochemical and Histological Findings

Neurochemical Research - This study was designed to evaluate the underlying protective mechanisms of oleuropein involved in alleviating brain damage in a rat model of ischemic stroke. Male Wistar...     

Spatio-temporal drivers of different oomycete beta diversity components in Brazilian rivers

Disentangling the role of mechanisms driving metacommunity structure is fundamental for conservation strategies. Several studies have been done in aquatic communities; however, little is known about the factors driving oomycete communities. This research aimed to investigate beta diversity patterns and assess the role of environmental (chemical, physical, and hydrologic), spatial, and temporal (sampling months) factors in driving oomycete beta diversity in a spatial extent of 33 km from two Brazilian rivers. We took water samples in 10 sites quarterly, from August 2017 to May 2018. The partition of beta diversity into its components – species replacement and richness difference – was performed using the Jaccard dissimilarity index. Distance-based redundancy analysis and variation partitioning were used to assess the relationship between explanatory variables and beta diversity. We found that beta diversity was spatially and temporally high, and the replacement component was the main driver of the oomycete metacommunity’s beta diversity. Replacement and total beta diversity were explained mainly by spatial location and the month of sampling, while the richness difference was more associated with the environmental variables chlorophyll a and ammonia. Our findings suggest that dispersal limitation (spatial) and temporal factors are the main drivers of the total beta diversity and replacement in the oomycete metacommunity, while species sorting (environmental factor) influences the richness difference. Accordingly, that taking temporal factors into account in metacommunity studies is important to explain beta diversity patterns, especially in rivers with remarkable variability in hydrological regime and under eutrophic conditions.

     

Paracoccidioidomycosis due to Paracoccidioides brasiliensis S1 associated with acquired immunodeficiency syndrome: A case report

BackgroundParacoccidioidomycosis (PCM) is an endemic disease in Latin America. In immunocompetent hosts, PCM occurs in two main clinical forms: acute and chronic. However, in HIV-infected patients PCM may show up simultaneous manifestations of acute and chronic forms.Case reportWe present the case of a patient diagnosed with HIV who had disseminated skin lesions and generalized lymphadenopathy, as well as respiratory and central nervous system involvement. The PCM diagnosis was confirmed by direct KOH examination, double immunodiffusion and the isolation of the fungus in samples of an abscess in the subcostal region. The isolate was identified as Paracoccidioides brasiliensis S1 by species-specific PCR using primers for protein-coding gene GP43 (exon 2) followed by PCR-RFLP of the alpha-tubulin gene.ConclusionsThere are few data in literature reporting species-specific molecular identification of Paracoccidioides in HIV/PCM patients. Therefore, this case report may contribute to improve the knowledge about this severe disease, its causative cryptic species, and its consequences to patients.     

Role of the inhibitor of serine peptidase 2 (ISP2) of Trypanosoma brucei rhodesiense in parasite virulence and modulation of the inflammatory responses of the host

Trypanosoma brucei rhodesiense is one of the causative agents of Human African Trypanosomiasis (HAT), known as sleeping sickness. The parasite invades the central nervous system and causes severe encephalitis that is fatal if left untreated. We have previously identified ecotin-like inhibitors of serine peptidases, named ISPs, in trypanosomatid parasitic protozoa. Here, we investigated the role of ISP2 in bloodstream form T. b. rhodesiense. We generated gene-deficient mutants lacking ISP2 (Δisp2), which displayed a growth profile in vitro similar to that of wild-type (WT) parasites. C57BL/6 mice infected with Δisp2 displayed lower blood parasitemia, a delayed hind leg pathological phenotype and survived longer. The immune response was examined at two time-points that corresponded with two peaks of parasitemia. At 4 days, the spleens of Δisp2-infected mice had a greater percentage of NOS2⁺ myeloid cells, IFN-γ⁺-NK cells and increased TNF-α compared to those infected with WT and parasites re-expressing ISP2 (Δisp2:ISP2). By 13 days the increased NOS2⁺ population was sustained in Δisp2-infected mice, along with increased percentages of monocyte-derived dendritic cells, as well as CD19⁺ B lymphocytes, and CD8⁺ and CD4⁺ T lymphocytes. Taken together, these findings indicate that ISP2 contributes to T. b. rhodesiense virulence in mice and attenuates the inflammatory response during early infection.     

High-fat diet based on dried bovine brain: an effective animal model of dyslipidemia and insulin resistance

Currently, there are no reports in the literature demonstrating any animal model that ingests one of the fattiest animal food source, the bovine brain. We hypothesized that a high-fat diet (HFD), based on dried bovine brain, could be used to develop an animal model possessing a spectrum of insulin resistance-related features. The HFD was formulated with 40% dried bovine brain plus 16.4% butter fat, prepared in-house. Furthermore, the diet contained 52% calories as fat and 73% of total fatty acids were saturated. Swiss mice weighing about 40 g were assigned to two dietary groups (n = 6/group), one group received a standard chow diet and the other was given HFD for 3 months. The body weight and biochemical parameters of the animals were measured initially and at monthly intervals until the end of the experiment. Animals fed on a HFD showed a significant increase in the body and adipose tissue weight, serum total cholesterol and triglyceride levels, when compared with mice fed on the control diet. Additionally, the HFD group showed higher circulating levels of liver transaminases, such as alanine aminotransferase and aspartate aminotransferase, compared with the control group. Finally, to illustrate the usefulness of this model, we report that the HFD induced mild hyperglycemia, fasting hyperinsulinemia, and increased the homeostasis model of assessment (HOMA-IR), in comparison with the control group. In conclusion, our results show that HFD, based on dried bovine brain, causes insulin resistance-related metabolic disturbances. Thus, this may be a suitable model to study disturbances in energy metabolism and their consequences.     

Bacterial structure and characterization of plant growth promoting and oil degrading bacteria from the rhizospheres of mangrove plants

Most oil from oceanic spills converges on coastal ecosystems, such as mangrove forests, which are threatened with worldwide disappearance. Particular bacteria that inhabit the rhizosphere of local plant species can stimulate plant development through various mechanisms; it would be advantageous if these would also be capable of degrading oil. Such bacteria may be important in the preservation or recuperation of mangrove forests impacted by oil spills. This study aimed to compare the bacterial structure, isolate and evaluate bacteria able to degrade oil and stimulate plant growth, from the rhizospheres of three mangrove plant species. These features are particularly important taking into account recent policies for mangrove bioreme-diation, implying that oil degradation as well as plant maintenance and health are key targets. Fifty-seven morphotypes were isolated from the mangrove rhizospheres on Bushneil-Haas (BH) medium supplemented with oil as the sole carbon source and tested for plant growth promotion. Of this strains, 60% potentially fixed nitrogen, 16% showed antimicrobial activity, 84% produced siderophores, 51% had the capacity to solubilize phosphate, and 33% produced the indole acetic acid hormone. Using gas chromatography, we evaluated the oil-degrading potential of ten selected strains that had different morphologies and showed Plant Growth Promoting Rhizobacteria (PGPR) features. The ten tested strains showed a promising degradation profile for at least one compound present in the oil. Among degrader strains, 46% had promising PGPR potential, having at least three of the above capacities. These strains might be used as a consortium, allowing the concomitant degradation of oil and stimulation of mangrove plant survival and maintenance.     

Species identification of Aspergillus section Flavi isolates from Portuguese almonds using phenotypic, including MALDI-TOF ICMS, and molecular approaches

AIMS: Section Flavi is one of the most significant sections in the genus Aspergillus. Taxonomy of this section currently depends on multivariate approaches, entailing phenotypic and molecular traits. This work aimed to identify isolates from section Flavi by combining various classic phenotypic and genotypic methods as well as the novel approach based on spectral analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF ICMS) and to evaluate the discriminatory power of the various approaches in species identification. METHODS AND RESULTS: Aspergillus section Flavi isolates obtained from Portuguese almonds were characterized in terms of macro- and micromorphology, mycotoxin pattern, calmodulin gene sequence and MALDI-TOF protein fingerprint spectra. For each approach, dendrograms were created and results were compared. All data sets divided the isolates into three groups, corresponding to taxa closely related to Aspergillus flavus, Aspergillus parasiticus and Aspergillus tamarii. In the A. flavus clade, molecular and spectral analyses were not able to resolve between aflatoxigenic and nonaflatoxigenic isolates. In the A. parasiticus cluster, two well-resolved clades corresponded to unidentified taxa, corresponding to those isolates with mycotoxin profile different from that expected for A. parasiticus.     

Succination of proteins in diabetes

Cysteine is arguably the most reactive amino acid in protein. A wide range of cysteine derivatives is formed in vivo, resulting from oxidation, nitrosation, alkylation and acylation reactions. This review describes succination of proteins, an irreversible chemical modification of cysteine by the Krebs cycle intermediate, fumarate, yielding S-(2-succinyl)cysteine (2SC). Intracellular fumarate concentration and succination of proteins are increased by hyperpolarization of the inner mitochondrial membrane and develop in concert with mitochondrial and oxidative stress in diabetes. Increased succination of glyceraldehyde-3-phosphate dehydrogenase explains the loss in specific activity of this enzyme in muscle of streptozotocin-diabetic rats and increased succination of adiponectin may explain the decreased secretion of adiponectin from adipose tissue in type 2 diabetes. In addition to GAPDH and adiponectin, other succinated proteins identified in adipocytes include cytoskeletal proteins (tubulin, actin) and chaperone proteins in the endoplasmic reticulum. Succination of adipocyte protein in vitro is inhibited by uncouplers of oxidative phosphorylation and by inhibitors of ER stress. 2SC serves as a biomarker of mitochondrial stress and recent studies suggest that succination is the mechanistic link between mitochondrial and ER stress in diabetes.     

The binding of synthetic triiodo l-thyronine analogs to human transthyretin: molecular basis of cooperative and non-cooperative ligand recognition

Transthyretin (TTR) is a tetrameric β-sheet-rich transporter protein directly involved in human amyloid diseases. Several classes of small molecules can bind to TTR delaying its amyloid fibril formation, thus being promising drug candidates to treat TTR amyloidoses. In the present study, we characterized the interactions of the synthetic triiodo L-thyronine analogs and thyroid hormone nuclear receptor TRβ-selective agonists GC-1 and GC-24 with the wild type and V30M variant of human transthyretin (TTR). To achieve this aim, we conducted in vitro TTR acid-mediated aggregation and isothermal titration calorimetry experiments and determined the TTR:GC-1 and TTR:GC-24 crystal structures. Our data indicate that both GC-1 and GC-24 bind to TTR in a non-cooperative manner and are good inhibitors of TTR aggregation, with dissociation constants for both hormone binding sites (HBS) in the low micromolar range. Analysis of the crystal structures of TTRwt:GC-1(24) complexes and their comparison with the TTRwt X-ray structure bound to its natural ligand thyroxine (T4) suggests, at the molecular level, the basis for the cooperative process displayed by T4 and the non-cooperative process provoked by both GC-1 and GC-24 during binding to TTR.     

Mucopolysaccharidoses in northern Brazil: Targeted mutation screening and urinary glycosaminoglycan excretion in patients undergoing enzyme replacement therapy

Mucopolysaccharidoses (MPS) are rare lysosomal disorders caused by the deficiency of specific lysosomal enzymes responsible for glycosaminoglycan (GAG) degradation. Enzyme Replacement Therapy (ERT) has been shown to reduce accumulation and urinary excretion of GAG, and to improve some of the patients' clinical signs. We studied biochemical and molecular characteristics of nine MPS patients (two MPS I, four MPS II and three MPS VI) undergoing ERT in northern Brazil. The responsiveness of ERT was evaluated through urinary GAG excretion measurements. Patients were screened for eight common MPS mutations, using PCR, restriction enzyme tests and direct sequencing. Two MPS I patients had the previously reported mutation p.P533R. In the MPS II patients, mutation analysis identified the mutation p.R468W, and in the MPS VI patients, polymorphisms p.V358M and p.V376M were also found. After 48 weeks of ERT, biochemical analysis showed a significantly decreased total urinary GAG excretion in patients with MPS I (p < 0.01) and MPS VI (p < 0.01). Our findings demonstrate the effect of ERT on urinary GAG excretion and suggest the adoption of a screening strategy for genotyping MPS patients living far from the main reference centers.