The IRAK1/IRF5 axis initiates IL-12 response by dendritic cells and control of Toxoplasma gondii infection

Activation of endosomal Toll-like receptor (TLR) 7, TLR9, and TLR11/12 is a key event in the resistance against the parasite Toxoplasma gondii. Endosomal TLR engagement leads to expression of interleukin (IL)-12 via the myddosome, a protein complex containing MyD88 and IL-1 receptor-associated kinase (IRAK) 4 in addition to IRAK1 or IRAK2. In murine macrophages, IRAK2 is essential for IL-12 production via endosomal TLRs but, surprisingly, Irak2-/- mice are only slightly susceptible to T. gondii infection, similar to Irak1-/- mice. Here, we report that upon T. gondii infection IL-12 production by different cell populations requires either IRAK1 or IRAK2, with conventional dendritic cells (DCs) requiring IRAK1 and monocyte-derived DCs (MO-DCs) requiring IRAK2. In both populations, we identify interferon regulatory factor 5 as the main transcription factor driving the myddosome-dependent IL-12 production during T. gondii infection. Consistent with a redundant role of DCs and MO-DCs, mutations that affect IL-12 production in both cell populations show high susceptibility to infection in vivo.

Transcriptomic analysis reveals that RasGEF1b deletion alters basal and LPS-induced expression of genes involved in chemotaxis and cytokine responses in macrophages

Ras guanine nucleotide exchange factor member 1b (RasGEF1b) of the RasGEF/CDC25 domain-containing family is preferentially expressed by macrophages. However, information is lacking about its role in macrophage function. In this study, we generated mice with ubiquitous deletion of Rasgef1b and used RNA-seq-based transcriptomics to compare the global gene expression in wild-type and knock-out primary bone-marrow-derived macrophages under basal conditions and after lipopolysaccharide (LPS) treatment. Transcriptional filtering identified several genes with significantly different transcript levels between wild-type and knock-out macrophages. In total, 49 and 37 differentially expressed genes were identified at baseline and in LPS-activated macrophages, respectively. Distinct biological processes were significantly linked to down-regulated genes at the basal condition only, and largely included chemotaxis, response to cytokines, and positive regulation of GTPase activity. Importantly, validation by RT-qPCR revealed that the expression of genes identified as down-regulated after LPS stimulation was also decreased in the knock-out cells under basal conditions. We used a luciferase-based reporter assay to showcase the capability of RasGEF1b in activating the Serpinb2 promoter. Notably, knockdown of RasGEF1b in RAW264.7 macrophages resulted in impaired transcriptional activation of the Serpinb2 promoter, both in constitutive and LPS-stimulated conditions. This study provides a small collection of genes that shows relative expression changes effected by the absence of RasGEF1b in macrophages. Thus, we present the first evidence that RasGEF1b mediates the regulation of both steady-state and signal-dependent expression of genes and propose that this GEF plays a role in the maintenance of the basal transcriptional level in macrophages.

Genetic diversity of Plathymenia reticulata Benth. in fragments of Atlantic Forest in southeastern Brazil

Studies of genetic diversity in natural populations are important for the definition of conservation strategies, especially in populations reduced by processes of fragmentation and continuous forest extraction. Molecular markers stand out as interesting tools for these studies. The objective of this research was to characterize the diversity and genetic structure of Plathymenia reticulata (Fabaceae), occurring in two fragments of the Montana Semideciduous Forest in the southern of Espírito Santo State, Brazil, using inter-simple sequence repeat (ISSR) molecular markers. DNA samples from 149 individuals were analyzed using 10 ISSR primers, generating 156 fragments, of which 101 were polymorphic (64.74%). The individuals sampled were classified into three units: adult trees (A), a mixture of progenies (B), and young regenerating individuals (C). The number of loci used (N = 101) was greater than that established as optimal number (N = 88), indicating precision in analyses. The genetic diversity index of Nei (H' = 0.407) and the Shannon index (I = 0.594) were found to have high genetic diversity. Besides, through the diversity parameters evaluated, it was possible to confirm that in the areas of natural regeneration and progeny mix there is genetic diversity equivalent to that found in adults. The analysis of molecular variance indicated that most of the genetic variation is found within the groups (96.53%). Genetic differentiation among adult trees was low (Φ_ST = 0.03) indicating that high gene flow rates (N_m = 12.70) are counteracting the effects of genetic drift. The data obtained allowed to evaluate the potential of adult trees as matrices for seed collection and to obtain seedlings with confirmed genetic variability.

Chronic Toxoplasma gondii Infection Exacerbates Secondary Polymicrobial Sepsis

Sepsis is a severe syndrome that arises when the host response to an insult is exacerbated, leading to organ failure and frequently to death. How a chronic infection that causes a prolonged Th1 expansion affects the course of sepsis is unknown. In this study, we showed that mice chronically infected with Toxoplasma gondii were more susceptible to sepsis induced by cecal ligation and puncture (CLP). Although T. gondii-infected mice exhibited efficient control of the bacterial burden, they showed increased mortality compared to the control groups. Mechanistically, chronic T. gondii infection induces the suppression of Th2 lymphocytes via Gata3-repressive methylation and simultaneously induces long-lived IFN-γ-producing CD4⁺ T lymphocytes, which promotes systemic inflammation that is harmful during CLP. Chronic T. gondii infection intensifies local and systemic Th1 cytokines as well as nitric oxide production, which reduces systolic and diastolic arterial blood pressures after sepsis induction, thus predisposing the host to septic shock. Blockade of IFN-γ prevented arterial hypotension and prolonged the host lifespan by reducing the cytokine storm. Interestingly, these data mirrored our observation in septic patients, in which sepsis severity was positively correlated to increased levels of IFN-γ in patients who were serologically positive for T. gondii. Collectively, these data demonstrated that chronic infection with T. gondii is a critical factor for sepsis severity that needs to be considered when designing strategies to prevent and control the outcome of this devastating disease.

Local inhibition of nitrergic activity in tenotomized rats accelerates muscle regeneration by increasing fiber area and decreasing central core lesions

Muscular atrophy is a progressive degeneration characterized by muscular proteolysis, loss of mass and decrease in fiber area. Tendon rupture induces muscular atrophy due to an intrinsic functional connection. Local inhibition of nitric oxide synthase (NOS) by Nω-nitro-L-arginine methyl ester (L-NAME) accelerates tendon histological recovery and induces functional improvement. Here we evaluate the effects of such local nitrergic inhibition on the pattern of soleus muscle regeneration after tenotomy. Adult male Wistar rats (240 to 280 g) were divided into four experimental groups: control (n=4), tenotomized (n=6), vehicle (n=6), and L-NAME (n=6). Muscular atrophy was induced by calcaneal tendon rupture in rats. Changes in muscle wet weight and total protein levels were determined by the Bradford method, and muscle fiber area and central core lesion (CCL) occurrence were evaluated by histochemical assays. Compared to tenotomized (69.3±22%) and vehicle groups (68.1%±17%), L-NAME treatment induced an increase in total protein level (108.3±21%) after 21 days post-injury. A reduction in fiber areas was observed in tenotomized (56.3±1.3%) and vehicle groups (53.9±3.9%). However, L-NAME treatment caused an increase in this parameter (69.3±1.6%). Such events were preceded by a remarkable reduction in the number of fibers with CCL in L-NAME-treated animals (12±2%), but not in tenotomized (21±2.5%) and vehicle groups (19.6±2.8%). Altogether, our data reveal that inhibition of tendon NOS contributed to the attenuation of atrophy and acceleration of muscle regeneration.

Non-destructive linear model for leaf area estimation in Vernonia ferruginea Less

Leaf area estimation is an important biometrical trait for evaluating leaf development and plant growth in field and pot experiments. We developed a non-destructive model to estimate the leaf area (LA) of Vernonia ferruginea using the length (L) and width (W) leaf dimensions. Different combinations of linear equations were obtained from L, L2, W, W2, LW and L2W2. The linear regressions using the product of LW dimensions were more efficient to estimate the LA of V. ferruginea than models based on a single dimension (L, W, L2 or W2). Therefore, the linear regression "LA=0.463+0.676WL" provided the most accurate estimate of V. ferruginea leaf area. Validation of the selected model showed that the correlation between real measured leaf area and estimated leaf area was very high.

Renin-angiotensin system contributes to naive T-cell migration in vivo

Angiotensin II (Ang II) plays an important role in the regulation of the T-cell response during inflammation. However, the cellular mechanisms underlying the regulation of lymphocytes under physiologic conditions have not yet been studied. Here, we tested the influence of Ang II on T-cell migration using T cells from BALB/c mice. The results obtained in vivo showed that when Ang II production or the AT1 receptor were blocked, T-cell counts were enhanced in blood but decreased in the spleen. The significance of these effects was confirmed by observing that these cells migrate, through fibronectin to Ang II via the AT1 receptor. We also observed a gradient of Ang II from peripheral blood to the spleen, which explains its chemotactic effect on this organ. The following cellular mechanisms were identified to mediate the Ang II effect: upregulation of the chemokine receptor CCR9; upregulation of the adhesion molecule CD62L; increased production of the chemokines CCL19 and CCL25 in the spleen. These results indicate that the higher levels of Ang II in the spleen and AT1 receptor activation contribute to migration of naive T cells to the spleen, which expands our understanding on how the Ang II/AT1 receptor axis contributes to adaptive immunity.

Non-destructive equations to estimate the leaf area of Styrax pohlii and Styrax ferrugineus

We developed linear equations to predict the leaf area (LA) of the species Styrax pohlii and Styrax ferrugineus using the width (W) and length (L) leaf dimensions. For both species the linear regression (Y=α+bX) using LA as a dependent variable vs. W × L as an independent variable was more efficient than linear regressions using L, W, L2 and W2 as independent variables. Therefore, the LA of S. pohlii can be estimated with the equation LA=0.582+0.683WL, while the LA of S. ferrugineus follows the equation LA=-0.666+0.704WL.

Iron-limited condition modulates biofilm formation and interaction with human epithelial cells of enteroaggregative Escherichia coli (EAEC)

AIMS

The aim of this study was to investigate the influence of low iron availability on biofilm formation and adherence to HEp-2 cells of enteroaggregative Escherichia coli (EAEC) strains isolated from diarrhoea cases.

METHODS AND RESULTS

The ability of EAEC to form biofilm on a plastic surface was evaluated quantitatively and qualitatively after 3 and 18 h of incubation of strains with or without the iron chelator 2,2-dipyridyl. When submitted to low iron conditions, prototype EAEC 042 strain showed a decrease in biofilm formation. Conversely, an increase in biofilm formation was observed for the clinical EAEC strains cultured in restricted iron condition. Moreover, the reduction of iron concentration inhibited the aggregative adherence to HEp-2 cells of all EAEC strains tested. However, all effects promoted by iron chelation were suppressed by thiourea.

CONCLUSIONS

Low iron availability may modulate biofilm formation and adhesive properties of EAEC strains to HEp-2 cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

The data obtained in this study provide useful insights on the influence of low iron conditions possibly associated with redox stress on the pathogenesis of EAEC strains.

Adjuvant effect of synthetic oligodeoxyribonucleotides (CpG-ODN) from the Paracoccidioides brasiliensis gp43 gene on the Th2-Th1 immunomodulation of experimental paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is caused by the dimorphic fungus Paracoccidioides brasiliensis. Immunostimulatory effects of P. brasiliensis DNA and CpG-oligodeoxyribonucleotides (CpG-ODN) have shown a Th2-Th1 immunomodulation of the isogenic murine model of susceptibility, which develops a progressive and disseminating disease. In this study, we investigated the optimum time interval and doses of CpG-ODN which are able to induce Th2-Th1 immunomodulation. The optimum concentrations for the induction of a decrease in antibody production were 0.5 and 1 microg. Mice immunized twice with CpG-ODN and gp43 (5 and 7 days before the challenge) showed a 60% higher chance of survival compared with the control group (nonimmunized), and an increase in Th1 isotype (IgG2a) was also observed. In vitro assays of naive and preimmunized mice showed discrete cellular proliferation when stimulated by suitable concentrations of CpG-ODN. Type 1 cytokines interleukin-12 (IL-12) and interferon-gamma were increased in cell culture supernatants, but no significant difference was found in Th2 IL-4 cytokines in stimulated or nonstimulated cell cultures. Concerning the Th2-Th1 kinetics in experimental PCM models by adjuvant effect of CpG-ODN, there are still many questions to be answered and clarified. However, the gathering of data obtained in this investigation has led us to suggest that the modulation of Th2-Th1 in experimental PCM depends on time and CpG-ODN concentration.

Antiprotozoal and molluscicidal activities of five Brazilian plants

Leishmaniasis, Chagas' disease and schistosomiasis (bilharzia) are parasitic diseases with wide distribution on the American continent, affecting millions of people. In the present study, biological assays for antiprotozoal and molluscicidal activities were carried out with ethanolic extracts of plant species from the Brazilian part of the Upper Paraná River. Crude extracts were obtained by percolation with absolute ethanol from the leaves of Cayaponia podantha Cogn., Nectandra falcifolia (Nees) Castiglioni and Paullinia elegans Cambess., as well as from the aerial parts of Helicteres gardneriana St. Hil. & Naud. and Melochia arenosa Benth., all belonging to genera used in folk medicine. Trypanocidal activity of plants was assayed on epimastigote cultures in liver infusion tryptose. Anti-leishmanial activity was determined over cultures of promastigote forms of the parasite in Schneider's Drosophila medium. Microscopic countings of parasites, after their incubation in the presence of different concentrations of the crude extracts, were made in order to determine the percentage of growth inhibition. C. podantha and M. arenosa, at a concentration of 10 microg/mL, showed 90.4 +/- 11.52 and 88.9 +/- 2.20% growth inhibition, respectively, of epimastigote forms of Trypanosoma cruzi, whereas N. falcifolia demonstrated an LD50 of 138.5 microg/mL against promastigote forms of Leishmania (Viannia) braziliensis. Regarding molluscicidal activity, the acute toxicity of the extracts on Biomphalaria glabrata was evaluated by a rapid screening procedure. M. arenosa was 100% lethal to snails at 200 microg/mL and showed an LD50 of 143 microg/mL. Screening of plant extracts represents a continuous effort to find new antiparasitic drugs.

Anurans from a local assemblage in Central Brazil: linking local processes with macroecological patterns

Macroecological variables of Anuran species found in a local assemblage from Central Brazil (Silvânia, Goiás State) were linked to population dynamics statistics of these species. Geographical range size (GRS), body size, and species' midpoints were the macroecological variables investigated for those species found in the local assemblage and for all other species (105 in the total) found in the Cerrado biome. For each species found in the local assemblage, data on abundance was obtained. Using this data, local population variability as expressed by the coefficient of variation was estimated. Distribution of means, medians, maximum, variances, and skewness (g1), for both GRS and body size, estimated in the local assemblage were compared, using null models, with the data extracted from the overall Cerrado species pool. The results indicated a clear macroecological relationship between GRS and body size and a decrease in local abundance when distance between the locality analyzed and species midpoint increased. According to null models, both body size and GRS values measured in the local assemblage can be considered a random sample from the regional species pool (Cerrado region). Finally, a three-dimensional analysis using body size, GRS, and local population estimates (abundance and variability), indicated that less abundant and more fluctuating species fell near the lower boundary of the polygonal relationship between GRS and body size. Thus, macroecological results linked with local data on population dynamics supported the minimum viable population model.

Evaluation of anti-inflammatory activity of essential oils from two Asteraceae species

The essential oils from two Asteraceae species, Porophyllum ruderale (PR) and Conyza bonariensis (CB) were screened for anti-inflammatory activity in the mouse model of pleurisy induced by zymosan (500 microg/cavity) and lipopolysaccharide (LPS) (250 ng/cavity). The main monoterpene constituents of each oil, beta-myrcene (in PR) and limonene (in CB), were tested in the LPS-induced pleurisy model and assayed also for immunoregulatory activity by measurement of the inhibition of NO and production of the cytokines, gamma-interferon and IL-4. The oils, when administered orally, were able to inhibit the LPS-induced inflammation including cell migration; with a similar effect being observed for pure limonene. Pure beta-myrcene and limonene were also effective in inhibiting production of nitric oxide at doses below the cytotoxicity of these monoterpenes. A significant inhibition of gamma-interferon and IL-4 production by limonene and beta-myrcene was also observed.

Immunostimulatory DNA from Paracoccidioides brasiliensis acts as T-helper 1 promoter in susceptible mice

Th1 immune responses afford protection against some pathogens like the fungus P. brasiliensis (P.b.), etiological agent of Paracoccidioidomycosis (PCM). It is well known that nonmethylated CpG sequences from bacterial DNA have immunomodulatory properties and can be used as a Th1-promoting adjuvant. By analyzing the available gene sequences of P.b. we observed a high number of unmethylated CpG dinucleotides. In a murine model of the PCM infection, the isogenic mouse strain known to be susceptible presents a predominant Th2 pattern. In order to access the possibility of the genomic DNA to act as a Th1-promoting adjuvant, in vitro assays were made and indicated a significant increase in phagocytosis when the macrophages were stimulated with DNA from P.b. and in vivo assays of a decreased production of antibodies antigp43, the main antigen of the PCM system. The analysis of the antibody isotypes and the cytokine production suggested a Th1 modulation in the susceptible animals. Thus, when mice were infected with fungus plus synthetic oligodeoxynucleotide (ODN), made from the available sequence of gp43, a decrease in the fungus dissemination was observed. Results herein described suggest that genomic DNA from P.b. could have a immunostimulatory function as a Th-1-promoting adjuvant in susceptible mice.

[Reflections on the teaching to undergraduate nurses about group dynamics]

The present article aims at reflecting on the experience of the authors about the nursing undergraduate teaching on group dynamics, that began in 1992. Authors focus nursing and the works with groups; the structure, content and development of this specific course.

[Psychiatric nursing production in Brazil, 1932-1993]

The present research aims at studying the psychiatric nursing bibliographical production in Brazil, from 1932 to 1993. Therefore, the authors searched national journals, annals of the Brazilian Nursing Congresses, Annals of the National Seminars on Nursing Research and Catalogues of the Brazilian Nursing Association--Center of Nursing Studies and Research. In addition, the authors selected publications of the following events: III Meeting of Researchs on Mental Health, II Meeting of Specialists on Psychiatric Nursing, Nursing Undergraduation Golden Jubilee and National Meeting of University Hospitals. After the conclusion of this study, discussions were based on the central themes of the texts as well as on historical development of Psychiatric Nursing in Brazil.

Effects of crating and transport on stress and meat quality characteristics in broilers

Experiments were conducted to determine 1) whether different crating durations influence stress responses and meat quality in broilers, and 2) whether holding crated broilers after transport influences corticosterone (CORT) levels and meat quality. In a preliminary experiment, male broilers (n = 50) were held in crates (10 birds per crate) for either 0, 1, 2, 3, or 4 h prior to processing. Crating duration did not affect plasma CORT level, cooking loss, shear value of breast or thigh muscles, or carcass skin discolorations. Crating duration also did not affect the color (L*, a*, b*, chroma, and hue angle) of breast meat, but did change the color of thigh meat, with samples from the 3 h crating group having the highest hue values (P < 0.01). Corticosterone concentrations and hue values of thigh samples were positively correlated (P < 0.05, r = 0.244). In Experiment 1, broilers (n = 36) were crated for either 1 or 3 h, with 9 birds per crate. Crating time did not influence plasma CORT, epinephrine, or norepinephrine concentrations, initial pH, color, or texture of breast and thigh meat samples. In Experiment 2, broilers were crated (nine birds per crate) early in the morning and transported 3 h to the processing facility by truck. Nine crates of birds were held in a dark quiet place for 4 h prior to processing (H) and the remaining nine crates were processed immediately (NH). Corticosterone levels were significantly lower (P < 0.01) in the H group than in the NH group. Initial pH of thigh meat of the H group was also significantly lower (P < 0.01), although breast meat pH was not affected by treatment. Holding had no effect on shear values, color (breast and thigh), or total heme concentration (thigh). There was a significant correlation (P < 0.01, r = 0.302) between CORT levels and hue values of thigh meat. These results suggest that higher preslaughter stress levels in broilers could influence the color of thigh meat, although overall meat quality was not affected under the conditions of this study.

Differences in reactivity of paracoccidioidomycosis sera with gp43 isoforms

The glycoprotein gp43 from Paracoccidioides brasiliensis is the main antigenic component in paracoccidioidomycosis (PCM) because it is recognized by 100% of PCM patients. It has also been shown that different fungal strains produce gp43 with at least four isoform profiles. In this study, different isoform profiles from gp43, with pIs ranging from 5.8 to 8.5, were affinity purified from various P. brasiliensis (B-339, S.S., 1925 and I9) exoantigens. Because of the isoform heterogeneity, we questioned whether those isoform profiles could be similarly recognized by acute or chronic PCM patients. By using a specific and sensitive method for detection of human IgG anti-gp43 antibodies, the monoclonal antibody capture immunoassay, we report that not all gp43 isoform profiles are equally recognized in PCM sera when anti-gp43 MAb 17c was employed as capturing antibody. Our results showed that recognition of pI8.5 gp43 isoform was significantly lower for both acute (56%) and chronic patients (71%), compared with gp43 isoforms from the standard strain B-339. On the other hand, when anti-gp43 MAb 8a, which recognizes a different antigenic epitope was used to capture the different gp43 isoform profiles, all patient's sera reacted similarly. The results described suggest that not all the antigenic epitopes expressed by gp43 are equally present in all P. brasiliensis strains.

[Pathogenicity of equine influenza viruses in chickens]

In the present paper the pathogenicity of equine subtype A/equi 1 (H7N7) and A/equi 2 (H3N8) for chicks was studied. Strains previously isolated in Brazil, representatives of both subtypes, were used. Eight experiments were performed for A/equi 2, using 89 chicks (4 to 18-day old). Six hundred thirty three samples of cloacal material were collected from 01 to 15 days pos-infection (p.i.) and inoculated in 11-day old chick embryos for recuperation of virus. Twelve samples showed positive results. The recuperated viruses were identified with specific antiserum in hemagglutination inhibition test (HI). Blood samples of all chicks collected prior to infection showed no antibodies to both subtypes. Chicks inoculated with A/equi 2 virus were bled 18 to 21 days p.i. Out of 89, seventy one (79.8%) serums showed different levels of antibodies at HI tests. Seventy chicks were inoculated with A/equi 1 subtype. Five hundred forty three samples of cloacal material were harvested and inoculated in embryonated chick eggs. No recuperation of virus occurred. However, all the inoculated chickens showed seroconversion. Chicks infected with A/equi 2 may shed virus in feces. No signs of disease were noted in the inoculated chicks.

Enzyme linked immunosorbent assay: determination of anti-adenovirus antibodies in an infant population

In order to define an accurate assay for anti-adenovirus antibody detection, a recently developed ELISA was compared with IFA and CF. On 58 sera, the ELISA was more sensitive than both CF and IFA, which showed relative sensitivities of 63% and 94%, respectively. It was not possible to determine the exact specificity of the tests because of the lack of a gold standard. Furthermore, the ELISA was used to define the prevalence of adenovirus antibodies in 116 infants between 1 and 24 months old (mean 7.28). The data showed that maternal antibodies waned by the age of 5 to 6 months and that more than 80% of the children had been infected by adenoviruses by the age of 10 months.