Antagonistic Interplay between MicroRNA-155 and IL-10 during Lyme Carditis and Arthritis

MicroRNA-155 has been shown to play a role in immune activation and inflammation, and is suppressed by IL-10, an important anti-inflammatory cytokine. The established involvement of IL-10 in the murine model of Borrelia burgdorferi-induced Lyme arthritis and carditis allowed us to assess the interplay between IL-10 and miR-155 in vivo. As reported previously, Mir155 was highly upregulated in joints from infected severely arthritic B6 Il10^-/- mice, but not in mildly arthritic B6 mice. In infected hearts, Mir155 was upregulated in both strains, suggesting a role of miR-155 in Lyme carditis. Using B. burgdorferi-infected B6, Mir155^-/-, Il10^-/-, and Mir155^-/- Il10^-/- double-knockout (DKO) mice, we found that anti-inflammatory IL-10 and pro-inflammatory miR-155 have opposite and somewhat compensatory effects on myeloid cell activity, cytokine production, and antibody response. Both IL-10 and miR-155 were required for suppression of Lyme carditis. Infected Mir155^-/- mice developed moderate/severe carditis, had higher B. burgdorferi numbers, and had reduced Th1 cytokine expression in hearts. In contrast, while Il10^-/- and DKO mice also developed severe carditis, hearts had reduced bacterial numbers and elevated Th1 and innate cytokine expression. Surprisingly, miR-155 had little effect on Lyme arthritis. These results show that antagonistic interplay between IL-10 and miR-155 is required to balance host defense and immune activation in vivo, and this balance is particularly important for suppression of Lyme carditis. These results also highlight tissue-specific differences in Lyme arthritis and carditis pathogenesis, and reveal the importance of IL-10-mediated regulation of miR-155 in maintaining healthy immunity.     

Tempol Moderately Extends Survival in a hSOD1G93A ALS Rat Model by Inhibiting Neuronal Cell Loss,Oxidative Damage and Levels of Non-Native hSOD1G93A Forms

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive dysfunction and death of motor neurons by mechanisms that remain unclear. Evidence indicates that oxidative mechanisms contribute to ALS pathology, but classical antioxidants have not performed well in clinical trials. Cyclic nitroxides are an alternative worth exploring because they are multifunctional antioxidants that display low toxicity in vivo. Here, we examine the effects of the cyclic nitroxide tempol (4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl) on ALS onset and progression in transgenic female rats over-expressing the mutant hSOD1^G93A . Starting at 7 weeks of age, a high dose of tempol (155 mg/day/rat) in the rat´s drinking water had marginal effects on the disease onset but decelerated disease progression and extended survival by 9 days. In addition, tempol protected spinal cord tissues as monitored by the number of neuronal cells, and the reducing capability and levels of carbonylated proteins and non-native hSOD1 forms in spinal cord homogenates. Intraperitoneal tempol (26 mg/rat, 3 times/week) extended survival by 17 days. This group of rats, however, diverted to a decelerated disease progression. Therefore, it was inconclusive whether the higher protective effect of the lower i.p. dose was due to higher tempol bioavailability, decelerated disease development or both. Collectively, the results show that tempol moderately extends the survival of ALS rats while protecting their cellular and molecular structures against damage. Thus, the results provide proof that cyclic nitroxides are alternatives worth to be further tested in animal models of ALS.     

Patterns of Sleeping Site and Sleeping Tree Selection by Black-and-Gold Howler Monkeys (Alouatta caraya) in Northern Argentina

International Journal of Primatology - The selection of sleeping sites and sleeping trees in nonhuman primates is related to social and ecological factors. We investigate the role of body...     

Analysis of Immune Response Markers in Jorge Lobo's Disease Lesions Suggests the Occurrence of Mixed T Helper Responses with the Dominance of Regulatory T Cell Activity

Jorge Lobo’s disease (JLD) is a chronic infection that affects the skin and subcutaneous tissues. Its etiologic agent is the fungus Lacazia loboi. Lesions are classified as localized, multifocal, or disseminated, depending on their location. Early diagnosis and the surgical removal of lesions are the best therapeutic options currently available for JLD. The few studies that evaluate the immunological response of JLD patients show a predominance of Th2 response, as well as a high frequency of TGF-β and IL-10 positive cells in the lesions; however, the overall immunological status of the lesions in terms of their T cell phenotype has yet to be determined. Therefore, the objective of this study was to evaluate the pattern of Th1, Th2, Th17 and regulatory T cell (Treg) markers mRNA in JLD patients by means of real-time PCR. Biopsies of JLD lesions (N = 102) were classified according to their clinical and histopathological features and then analyzed using real-time PCR in order to determine the expression levels of TGF-β1, FoxP3, CTLA4, IKZF2, IL-10, T-bet, IFN-γ, GATA3, IL-4, IL-5, IL-13, IL-33, RORC, IL-17A, IL-17F, and IL-22 and to compare these levels to those of healthy control skin (N = 12). The results showed an increased expression of FoxP3, CTLA4, TGF-β1, IL-10, T-bet, IL-17F, and IL-17A in lesions, while GATA3 and IL-4 levels were found to be lower in diseased skin than in the control group. When the clinical forms were compared, TGF-β1 was found to be highly expressed in patients with a single localized lesion while IL-5 and IL-17A levels were higher in patients with multiple/disseminated lesions. These results demonstrate the occurrence of mixed T helper responses and suggest the dominance of regulatory T cell activity, which could inhibit Th-dependent protective responses to intracellular fungi such as L. loboi. Therefore, Tregs may play a key role in JLD pathogenesis.     

Altitudinal migration by birds: a review of the literature and a comprehensive list of species

Altitudinal migration is the seasonal altitudinal movement of birds from breeding areas to non‐breeding or wintering areas at different elevations. Although this type of migration is widely reported, questions remain concerning the number of species that perform altitudinal migration, possible variation among different taxa and geographic locations in the extent of altitudinal migration, and the foraging guilds of altitudinal migrants. We conducted an extensive bibliographic survey and compiled a list of altitudinal migrant birds worldwide. We characterized species in terms of their foraging guilds because the spatial distribution of food resources along altitudinal gradients is often evoked as a driver of bird altitudinal migration. We identified 1238 species of altitudinal migrants, ~10% of the ~10,000 extant species of birds. We found a strong geographic bias in publications focusing on avian altitudinal migration toward the United States and Costa Rica, and a paucity of studies in megadiverse regions such as the Afrotropical and Indomalayan realms, and areas in the Neotropics other than Costa Rica. We also found that most species of altitudinal migrants were invertivores rather than frugivores or nectarivores. This general pattern held true for all zoogeographic realms except the Neotropics, where nectarivores and frugivores predominated among altitudinal migrants. The prevalence of invertivore birds among altitudinal migrants is not unexpected because this is the most common foraging guild among birds worldwide. Overall, we found no prevalence of any specific foraging guild among altitudinal migrants across zoogeographic regions. The results of studies to date suggest that altitudinal migration by birds may be driven by a number of factors, including access to increased food resources for breeding or molting, weather conditions, and mating and nesting opportunities. However, to better understand the mechanisms underlying altitudinal migration, broadening the geographic scope of studies is paramount, with additional study of altitudinal migration especially needed in the megadiverse tropical regions of sub‐Saharan Africa, Southeast Asia, and South America.     

Soulamarin Isolated from Calophyllum brasiliense (Clusiaceae) Induces Plasma Membrane Permeabilization of Trypanosoma cruzi and Mytochondrial Dysfunction

Chagas disease is caused by the parasitic protozoan Trypanosoma cruzi. It has high mortality as well as morbidity rates and usually affects the poorer sections of the population. The development of new, less harmful and more effective drugs is a promising research target, since current standard treatments are highly toxic and administered for long periods. Fractioning of methanol (MeOH) extract of the stem bark of Calophyllum brasiliense (Clusiaceae) resulted in the isolation of the coumarin soulamarin, which was characterized by one- and two-dimensional ¹H- and ¹³C NMR spectroscopy as well as ESI mass spectrometry. All data obtained were consistent with a structure of 6-hydroxy-4-propyl-5-(3-hydroxy-2-methyl-1-oxobutyl)-6″,6″-dimethylpyrane-[2″,3″:8,7]-benzopyran-2-one for soulamarin. Colorimetric MTT assays showed that soulamarin induces trypanocidal effects, and is also active against trypomastigotes. Hemolytic activity tests showed that soulamarin is unable to induce any observable damage to erythrocytes (c_max. = 1,300 µM). The lethal action of soulamarin against T. cruzi was investigated by using amino(4-(6-(amino(iminio)methyl)-1H-indol-2-yl)phenyl)methaniminium chloride (SYTOX Green and 1H,5H,11H,15H-Xantheno[2,3,4-ij:5,6,7-i′j′]diquinolizin-18-ium, 9-[4-(chloromethyl)phenyl]-2,3,6,7,12,13,16,17-octahydro-chloride (MitoTracker Red) as fluorimetric probes. With the former, soulamarin showed dose-dependent permeability of the plasma membrane, relative to fully permeable Triton X-100-treated parasites. Spectrofluorimetric and fluorescence microscopy with the latter revealed that soulamarin also induced a strong depolarization (ca. 97%) of the mitochondrial membrane potential. These data demonstrate that the lethal action of soulamarin towards T. cruzi involves damages to the plasma membrane of the parasite and mitochondrial dysfunction without the additional generation of reactive oxygen species, which may have also contributed to the death of the parasites. Considering the unique mitochondrion of T. cruzi, secondary metabolites of plants affecting the bioenergetic system as soulamarin may contribute as scaffolds for the design of novel and selective drug candidates for neglected diseases, mainly Chagas disease.     

Molecular Features Related to HIV Integrase Inhibition Obtained from Structure- and Ligand-Based Approaches

Among several biological targets to treat AIDS, HIV integrase is a promising enzyme that can be employed to develop new anti-HIV agents. The aim of this work is to propose a mechanistic interpretation of HIV-1 integrase inhibition and to rationalize the molecular features related to the binding affinity of studied ligands. A set of 79 HIV-1 integrase inhibitors and its relationship with biological activity are investigated employing 2D and 3D QSAR models, docking analysis and DFT studies. Analyses of docking poses and frontier molecular orbitals revealed important features on the main ligand-receptor interactions. 2D and 3D models presenting good internal consistency, predictive power and stability were obtained in all cases. Significant correlation coefficients (r² = 0.908 and q² = 0.643 for 2D model; r² = 0.904 and q² = 0.719 for 3D model) were obtained, indicating the potential of these models for untested compounds. The generated holograms and contribution maps revealed important molecular requirements to HIV-1 IN inhibition and several evidences for molecular modifications. The final models along with information resulting from molecular orbitals, 2D contribution and 3D contour maps should be useful in the design of new inhibitors with increased potency and selectivity within the chemical diversity of the data.     

Consequences of refuge for the functional response of Dermestes ater (Coleoptera: Dermestidae) to Musca domestica (Diptera: Muscidae)

It is well known that a predator has the potential to regulate a prey population only if the predator responds to increases in prey density and inflicts greater mortality rates. Predators may cause such density-dependent mortality depending on the nature of the functional and numerical responses. Yet, few studies have examined the relationship between the addition of refuges and the characteristic of functional response fits. We investigated whether addition of a refuge changed the type of functional response exhibited by Dermestes ater on Musca domestica, comparing the inherent ability of D. ater to kill houseflies in the absence and in the presence of refuge. An additional laboratory experiment was also carried out to assess handling and searching times exhibited by D. ater. Logistic regression analyses revealed a type III functional response for predator–prey interaction without refuge, and results were described by the random predator equation. The mean number of prey killed did not differ between experimental habitats, indicating that the addition of refuge did not inhibit predation. However, predators that interacted with prey without refuge spent less time searching for prey at higher densities, increasing predatory interaction. We concluded that this interaction may be weak, because data from experiments with refuge fitted poorly to models. However, the high variability and the nonsignificance of the data from the experiment with refuge show the importance of refuge for promoting spatial heterogeneity, which may prevent prey extinction.     

Micropropagation of ‘Durondeau’ pear in modified-gelled medium

Summary The influence of partial substitution of agar by galactomannans (GMs) in culture media was studied in pear (Pyrus communis L. cv. ‘Durondeau’) micropropagation. GMs. extracted from seeds of Cassia fastuosa (cassia) or Cyamopsis tetragonolobus (guar gum, a commercial GM), were mixed in equal proportions with agar to a final concentration of 0.3% (w/v) for each type of gelling agent. The production of multiple shoots and the formation of roots from shoots were compared with the control solidified with agar alone at a concentration of 0.6% (w/v). In the media solidified with the mixtures of agar/guar and agar/cassia GMs, an, increase of 32 and 17%, respectively, was obtained in the number of regenerated shoots. The modified media promoted a higher number of roots and increased the rooting percentage. A maximum of 91% rooting was obtained in the medium solidified with the agar/cassia GM and containing 9.80 μM indole-3-butyric acid. Less callus formation at the base of the shoot was also observed on this medium. The improved in vitro performance of shoot formation and rooting, combined with a significantly lower cost, suggests a potential use of agar/GM gels in plant tissue culture.     

Colonization of Madagascar periwinkle (Catharanthus roseus), by endophytes encoding gfp marker

This study reports the introduction of gfp marker in two endophytic bacterial strains (Pantoea agglomerans C33.1, isolated from cocoa, and Enterobacter cloacae PR2/7, isolated from citrus) to monitor the colonization in Madagascar perinwinkle (Catharanthus roseus). Stability of the plasmid encoding gfp was confirmed in vitro for at least 72 h of bacterial growth and after the colonization of tissues, under non-selective conditions. The colonization was observed using fluorescence microscopy and enumeration of culturable endophytes in inoculated perinwinkle plants that grew for 10 and 20 days. Gfp-expressing strains were re-isolated from the inner tissues of surface-sterilized roots and stems of inoculated plants, and the survival of the P. agglomerans C33:1gfp in plants 20 days after inoculation, even in the absence of selective pressure, suggests that is good colonizer. These results indicated that both gfp-tagged strains, especially P. agglomerans C33.1, may be useful tools to deliver enzymes or other proteins in plant.