Myxobolus cuneus n. sp. (Myxosporea) infecting the connective tissue of Piaractus mesopotamicus (Pisces: Characidae) in Brazil: histopathology and ultrastructure

The characteristics of Myxobolus cuneus n. sp. and its relationship to the host Piaractus mesopotamicus are described based on light and electron microscopy and histological observations. Polysporic plasmodia measuring 20 microm to 2.1 mm in size were found in 63.3 % of the P. mesopotamicus examined. The parasite was found in the gall bladder, urinary bladder, gills, spleen, fins, head surface, liver and heart. Generative cells and disporoblastic pansporoblasts occurred along the periphery of the plasmodia, and mature spores were found in the internal region. The mature spores had a pear shaped body in frontal view, with a total length of 10.0 +/- 0.6 microm and a width of 5.1 +/- 0.3 microm (mean +/- SD). The spore wall was smooth with sutural folds. The polar capsules were elongated, were pear shaped, and equal in size (length 5.7 +/- 03 microm; width 1.7 +/- 0.2 microm), with the anterior ends close to each other. The polar filaments were tightly coiled in 8-9 turns perpendicular to the axis of the capsule. The plasmodia were always found in connective tissue (wall of the arterioles of the gill filaments, serous capsule of the gall bladder, middle layer and subepithelial connective tissue of the urinary bladder, connective tissue between the rays of the fins, subcutaneous tissue of the head surface and fibrous capsule spleen). The parasite caused important damage in the gills, where development occurred in the wall of gill filament arterioles; a mild macrophage infiltrate was also observed. In advanced developmental stages, the plasmodia caused deformation of the arteriole structure, with a reduction and, in some cases, obstruction of the lumen. The parasite was found throughout the period studied and its prevalence was unaffected by host size, season or water properties.     

A DNA vaccine encoding CCL4/MIP-1beta enhances myocarditis in experimental Trypanosoma cruzi infection in rats

Chagas' disease, caused by Trypanosoma cruzi, is a major cause of cardiovascular disease in Latin America. Exacerbated inflammation disproportional to parasite load characterizes chronic myocardial lesions in chagasic patients. Chemokines and their receptors are expected to account for the renewed inflammatory processes after the inoculation of the parasite, but their potential unique functions are far from being clear. Herein, we evaluated the effect of a DNA vaccine encoding CCL4/MIP-1beta, a CC-chemokine, in T. cruzi-elicited myocarditis in rats. Holtzman rats were given intramuscularly cardiotoxin and the CCL4/MIP-1beta DNA-containing plasmid (100microg) was delivered in this muscular site four times. Fourteen days after last immunization, animals were inoculated with a myotropical CL-Brener T. cruzi clone. Peak of parasitism was observed at day 15 after infection, preceding the peak of myocardial inflammation at day 20. Myocarditis was still intense at day 30, but the inflammatory infiltrates showed a more focal distribution. The expression of CCL2/MCP-1 and CCL4/MIP-1beta correlated closely with the kinetics of myocardial inflammation. The CCL4/MIP-1beta DNA vaccine induced an increase of the levels of the anti-CCL4/MIP-1beta observed in T. cruzi-infected animals. This was associated with an exacerbation of myocardial inflammation and fibrosis, although alterations in parasitemia and myocardial parasitism were not observed. Our data suggest that CCL4/MIP-1beta plays a role in preventing excessive inflammation and pathology rather than in controlling parasite replication.     

Detection of Helicobacter Species in the Gastrointestinal Tract of Wild Rodents From Brazil

Since we have limited knowledge about the occurrence of Helicobacter in wild animals, we searched for Helicobacter species in the gastrointestinal tract of 75 rodents captured in forest remnants of Minas Gerais, Brazil. Fragments from the antrum and corpus of the stomach and from the colon were taken for PCR assays for Helicobacter detection. Although gastric mucosa was Helicobacter-positive in only one animal, the bacterium was detected in the colonic mucosa of 23 rodents (30.7%). Helicobacter detection was more frequent in the colon of terraced rice rat (56%) and house rat (30%) in contrast to punare and Spix’s yellow-toothed cavy, in which the presence of the bacterium was not detected. Helicobacter rodentium, H. marmotae, H. cinaedi, and other species closely related to the murine helicobacters were presumptively identified by DNA sequencing. Wild rodents may serve as a reservoir of these Helicobacter species in nature.     

Bacteriocin-like substance inhibits potato soft rot caused by Erwinia carotovora

Soft rot is a major problem encountered in potatoes during postharvest storage. The soft rot bacterium Erwinia carotovora was inhibited by a novel bacteriocin-like substance (BLS) produced by Bacillus licheniformis P40. The BLS caused a bactericidal effect on E. carotovora cells at 30 microg mL(-1). Transmission electron microscopy showed that BLS-treated cells presented wrinkled bacterial surfaces and shrinkage of the whole cell, indicating plasmolysis. Erwinia carotovora cells treated with BLS were analyzed by FTIR showing differences in the 1390 cm(-1) and 1250-1220 cm(-1) bands, corresponding to assignments of membrane lipids. BLS was effective in preventing E. carotovora spoilage on potato tubers, reducing the symptoms of soft rot at 240 microg mL(-1) and higher concentrations. Soft rot development was completely blocked at 3.7 mg mL(-1). This BLS showed potential to protect potato tubers during storage.     

Cyclin-dependent kinase inhibitors enhance the resolution of inflammation by promoting inflammatory cell apoptosis

Apoptosis is essential for clearance of potentially injurious inflammatory cells and subsequent efficient resolution of inflammation. Here we report that human neutrophils contain functionally active cyclin-dependent kinases (CDKs), and that structurally diverse CDK inhibitors induce caspase-dependent apoptosis and override powerful anti-apoptosis signals from survival factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF). We show that the CDK inhibitor R-roscovitine (Seliciclib or CYC202) markedly enhances resolution of established neutrophil-dependent inflammation in carrageenan-elicited acute pleurisy, bleomycin-induced lung injury, and passively induced arthritis in mice. In the pleurisy model, the caspase inhibitor zVAD-fmk prevents R-roscovitine-enhanced resolution of inflammation, indicating that this CDK inhibitor augments inflammatory cell apoptosis. We also provide evidence that R-roscovitine promotes apoptosis by reducing concentrations of the anti-apoptotic protein Mcl-1. Thus, CDK inhibitors enhance the resolution of established inflammation by promoting apoptosis of inflammatory cells, thereby demonstrating a hitherto unrecognized potential for the treatment of inflammatory disorders.     

The influence of mandibular implant-retained overdentures in masticatory efficiency

doi: 10.1111/j.1741‐2358.2011.00539.x The influence of mandibular implant‐retained overdentures in masticatory efficiency Objective: To evaluate the masticatory efficiency of patients rehabilitated with conventional dentures (CDs) or implant‐retained mandibular overdentures. Background: Despite the evident benefits of implants on mastication as assessed by subjective patient‐based outcomes, the extent of implant overdenture treatment effect on food comminution is not well established. Materials and methods: A randomised clinical trial was carried out with 29 completely edentulous patients divided into two groups. The first group was rehabilitated with a mandibular overdenture retained by two splinted implants with bar‐clip system, while the second group was rehabilitated with a mandibular CD. Both groups also were rehabilitated with maxillary CDs. Masticatory efficiency and patient satisfaction were assessed 3 months after denture insertion. Masticatory efficiency was evaluated through the colorimetric method with the beads as the artificial test‐food. Comparisons for masticatory efficiency and patient satisfaction were performed using Student’s t‐test (α = 0.05). Results: No significant statistical difference was found for masticatory efficiency (p = 0.198). Patient overall satisfaction was significantly higher for the mandibular overdenture (p < 0.001). In addition, mandibular overdenture patients were significantly more satisfied with chewing experience (p < 0.05) and retention of the lower denture (p < 0.005). Conclusion: The results of this study suggest that mandibular overdenture significantly improves chewing experience, although limited effect on masticatory efficiency has been observed.     

Polythiophenes inhibit prion propagation by stabilizing prion protein (PrP) aggregates

Luminescent conjugated polymers (LCPs) interact with ordered protein aggregates and sensitively detect amyloids of many different proteins, suggesting that they may possess antiprion properties. Here, we show that a variety of anionic, cationic, and zwitterionic LCPs reduced the infectivity of prion-containing brain homogenates and of prion-infected cerebellar organotypic cultured slices and decreased the amount of scrapie isoform of PrP(C) (PrP(Sc)) oligomers that could be captured in an avidity assay. Paradoxically, treatment enhanced the resistance of PrP(Sc) to proteolysis, triggered the compaction, and enhanced the resistance to proteolysis of recombinant mouse PrP(23-231) fibers. These results suggest that LCPs act as antiprion agents by transitioning PrP aggregates into structures with reduced frangibility. Moreover, ELISA on cerebellar organotypic cultured slices and in vitro conversion assays with mouse PrP(23-231) indicated that poly(thiophene-3-acetic acid) may additionally interfere with the generation of PrP(Sc) by stabilizing the conformation of PrP(C) or of a transition intermediate. Therefore, LCPs represent a novel class of antiprion agents whose mode of action appears to rely on hyperstabilization, rather than destabilization, of PrP(Sc) deposits.     

Follicular dendritic cells emerge from ubiquitous perivascular precursors

The differentiation of follicular dendritic cells (FDC) is essential to the remarkable microanatomic plasticity of lymphoid follicles. Here we show that FDC arise from ubiquitous perivascular precursors (preFDC) expressing platelet-derived growth factor receptor β (PDGFRβ). PDGFRβ-Cre-driven reporter gene recombination resulted in FDC labeling, whereas conditional ablation of PDGFRβ(+)-derived cells abolished FDC, indicating that FDC originate from PDGFRβ(+) cells. Lymphotoxin-α-overexpressing prion protein (PrP)(+) kidneys developed PrP(+) FDC after transplantation into PrP(-) mice, confirming that preFDC exist outside lymphoid organs. Adipose tissue-derived PDGFRβ(+) stromal-vascular cells responded to FDC maturation factors and, when transplanted into lymphotoxin β receptor (LTβR)(-) kidney capsules, differentiated into Mfge8(+)CD21/35(+)FcγRIIβ(+)PrP(+) FDC capable of trapping immune complexes and recruiting B cells. Spleens of lymphocyte-deficient mice contained perivascular PDGFRβ(+) FDC precursors whose expansion required both lymphoid tissue inducer (LTi) cells and lymphotoxin. The ubiquity of preFDC and their strategic location at blood vessels may explain the de novo generation of organized lymphoid tissue at sites of lymphocytic inflammation.     

Evaluation of immobilized lipases on poly-hydroxybutyrate beads to catalyze biodiesel synthesis

Five microbial lipase preparations from several sources were immobilized by hydrophobic adsorption on small or large poly-hydroxybutyrate (PHB) beads and the effect of the support particle size on the biocatalyst activity was assessed in the hydrolysis of olive oil, esterification of butyric acid with butanol and transesterification of babassu oil (Orbignya sp.) with ethanol. The catalytic activity of the immobilized lipases in both olive oil hydrolysis and biodiesel synthesis was influenced by the particle size of PHB and lipase source. In the esterification reaction such influence was not observed. Geobacillus thermocatenulatus lipase (BTL2) was considered to be inadequate to catalyze biodiesel synthesis, but displayed high esterification activity. Butyl butyrate synthesis catalyzed by BTL2 immobilized on small PHB beads gave the highest yield (≈90 mmol L(-1)). In biodiesel synthesis, the catalytic activity of the immobilized lipases was significantly increased in comparison to the free lipases. Full conversion of babassu oil into ethyl esters was achieved at 72 h in the presence of Pseudozyma antarctica type B (CALB), Thermomyces lanuginosus lipase (Lipex(?) 100 L) immobilized on either small or large PHB beads and Pseudomonas fluorescens (PFL) immobilized on large PHB beads. The latter preparation presented the highest productivity (40.9 mg of ethyl esters mg(-1) immobilized protein h(-1)).     

Evaluation of the anti-inflammatory and antinociceptive properties of p-cymene in mice

We attempted to identify the antinociceptive and anti-inflammatory actions of the monoterpene p-cymene. Firstly, behavioural screening was carried out to verify the influence of p-cymene [25, 50, and 100 mg/kg intraperitoneal (i.p.)] on the central nervous system (CNS) activity. The antinociceptive activity of p-cymene was evaluated by the acetic acid-induced writhing response, formalin, and hot-plate test, respectively. The leukocyte migration induced by injection of carrageenan was used to assess the anti-inflammatory activity. p-Cymene showed depressant activity on CNS after 4 h of treatment and also a possible action on the autonomous nervous system (ANS), mainly at the dose of 100 mg/kg (i.p.). It was found that p-cymene (50 and 100 mg/kg, i.p.) significantly (p < 0.05) reduced the writhing responses induced by acetic acid. p-Cymene also decreased the licking time in the first and second phase, respectively, of the formalin test. The results of the hot-plate test showed that all doses of p-cymene increased significantly the latency time of the response to the thermal stimulus in both licking and jumping parameters. In addition, there was a significantly (p < 0.05) decreased leukocyte migration at all doses of p-cymene. The experimental data demonstrate that p-cymene possesses antinociceptive and anti-inflammatory activities.