Thermal Characteristics of Polybia scutellaris Nests (Hymenoptera: Vespidae) Using Computational Fluid Dynamics: A Possible Adaptation to Tropical Climates

Polybia scutellaris constructs huge nests characterized by numerous spinal projections on the surface. We investigated the thermal characteristics of P scutellaris nests in order to determine whether their nest temperature is homeothermically maintained and whether the spines play a role in the thermoregulation of the nests. In order to examine these hypotheses, we measured the nest temperature in a active nest and in an abandoned nest. The temperature in the active nest was almost stable at 27 degrees C, whereas that of the abandoned nest varied with changes in the ambient temperature, suggesting that nest temperature was maintained by the thermogenesis of colony individuals. In order to predict the thermal properties of the spines, a numerical simulation was employed. To construct a 3D-model of a P scutellaris nest, the nest architecture was simplified into an outer envelope and the surface spines, for both of which the initial temperature was set at 27 degrees C. The physical properties of the simulated nest were regarded to be those of wood since the nest of this species is constructed from plant materials. When the model was exposed to cool air (12 degrees C), the temperature was lower in the models with more spines. On the other hand, when the nest was heated (42 degrees C), the temperature increase was smaller in models with more spines. It is suggested that the spines act as a heat radiator, not as an insulator, against the changes in ambient temperature.

Protection against Paracoccidioides brasiliensis infection conferred by the prophylactic administration of native and recombinant ArtinM

We determined the prophylactic effect of both the d-mannose-binding lectin ArtinM extracted from the seeds of Artocarpus integrifolia (jackfruit) and its recombinant counterpart during the course of experimental paracoccidioidomycosis induced in BALB/c mice. Four experimental protocols of prophylaxis were employed to evaluate the most protective regimen of ArtinM administration. It was demonstrated that the best effect was obtained by administration of two ArtinM doses on days 10 and 3 before the challenge with Paracoccidioides brasiliensis. By following this protocol, the lungs of mice that received native or recombinant ArtinM exhibited reduced fungal burden and granuloma incidence. In addition, the protocol augmented contents of IL-12, IFN-gamma, TNF-alpha and NO. On the other hand, the control group consisting of untreated infected mice had higher pulmonary levels of IL-4 and IL-10. In conclusion, prophylaxis with ArtinM significantly reproduces the effect of its therapeutic administration, i.e, it confers resistance to P. brasiliensis infection in mouse models by promoting IL-12 production and favours Th1-immunity.

Therapeutic administration of KM+ lectin protects mice against Paracoccidioides brasiliensis infection via interleukin-12 production in a Toll-like receptor 2-dependent mechanism

KM+ is a mannose-binding lectin from Artocarpus integrifolia that induces interleukin (IL)-12 production by macrophages and protective T helper I immune response against Leishmania major infection. in this study, we performed experiments to evaluate the therapeutic activity of jackfruit KM+ (jfKM(+)) and its recombinant counterpart (rKM(+)) in experimental paracoccidioidomycosis. To this end, jfKM(+) or rKM(+) was administered to BALB/c mice 10 days after infection with Paracoccidiodes brasiliensis. Thirty days postinfection, lungs from the KM+-treated mice contained significantly fewer colony-forming units and little to no organized granulomas compared to the controls. In addition, lung homogenates from the KM+-treated mice presented higher levels of nitric oxide, IL-12, interferon-gamma, and tumor necrosis factor-a, whereas higher levels of IL-4 and IL-10 were detected in the control group. With mice deficient in IL-12, Toll-like receptor (TLR) 2, TLR4, or TLR adaptor molecule MyD88, we demonstrated that KM+ led to protection against P. brasiliensis infection through IL-12 production, which was dependent on TLR2. These results demonstrated a beneficial effect of KM+ on the severity of P. brasiliensis infection and may expand its potential use as a novel immunotherapeutic molecule.

Study of the antimicrobial peptide indolicidin and mutants in eukaryotic modelled membrane by molecular dynamics simulations

In this work the interaction of the antimicrobial peptide indolicidin (IND) and its mutants CP10A and CP11 with a eukaryotic membrane model was examined by molecular dynamics simulations. The aim was to analyse the behaviour of these antimicrobial peptides when they interact with a eukaryotic modelled membrane, thereby obtaining atomic detailed observations that are not experimentally available. In the simulations, the widely studied dipalmitoylphosphatidylcholine hydrated bilayer was used as a eukaryotic membrane model. In agreement with experimental observations, the peptides IND, CP10A, and CP11 insert into the bilayer differently; the peptides that insert more deeply present the major hemolytic activities. The hydrophobic residues are responsible for the insertion, but some Trp residues of the peptides remain at the bilayer/water interface because they interact with the bilayer choline groups by cation-pi interactions that should be important for recognition of eukaryotic membrane by the three studied peptides.

Characterization of temperature dependent and substrate-binding cleft movements in Bacillus circulans family 11 xylanase: A molecular dynamics investigation

Background: Xylanases (EC 3.2.1.8) hydrolyze xylan, one of the most abundant plant polysaccharides found in nature, and have many potential applications in biotechnology. Methods: Molecular dynamics simulations were used to investigate the effects of temperature between 298 to 338 K and xylobiose binding on residues located in the substrate-binding cleft of the family 11 xylanase from Bacillus circulans (BcX). Results: In the absence of xylobiose the BcX exhibits temperature dependent movement of the thumb region which adopts an open conformation exposing the active site at the optimum catalytic temperature (328 K). In the presence of substrate, the thumb region restricts access to the active site at all temperatures, and this conformation is maintained by substrate/protein hydrogen bonds involving active site residues, including hydrogen bonds between Tyr69 and the 2` hydroxyl group of the substrate. Substrate access to the active site is regulated by temperature dependent motions that are restricted to the thumb region, and the BcX/substrate complex is stabilized by extensive intermolecular hydrogen bonding with residues in the active site. General significance: These results call for a revision of both the ""hinge-bending"" model for the activity of group 11 xylanases, and the role of Tyr69 in the catalytic mechanism. (C) 2009 Elsevier B.V. All rights reserved.

Seasonal dynamics of a drosophilid (Diptera) assemblage and its potencial as bioindicator in open environments

Drosophila Fallen, 1823 (Diptera, Drosophilidae) is for long a well-established model organism for genetics and evolutionary research. The ecology of these flies, however, has only recently been better studied. Recent papers show that Drosophila assemblies can be used as bioindicators of forested environment degradation. In this work the bioindicator potential of drosophilids was evaluated in a naturally opened environment, a coastal strand-forest (restinga). Data from nine consecutive seasonal collections revealed strong temporal fluctuation pattern of the majority of Drosophila species groups. Drosophila willistoni group was more abundant at autumns, whereas D. cardini and D. tripunctata groups were, respectively, expressive at winters and springs, and D. repleta group at both seasons. The exotic species D. simulans Sturtevant, 1919 (from D. melanogaster group) and Zaprionus indianus Gupta, 1970 were most abundant at summers. Overall, the assemblage structure did not show the same characteristics of forested or urban environments, but was similar to the forests at winters and to cities at summers. This raises the question that this locality may already been under urbanization impact. Also, this can be interpreted as an easily invaded site for exotic species, what might lead to biotic homogenization and therefore can put in check the usage of drosophilid assemblages as bioindicators at open environments.

Religions and cultures: Religious dynamics in Latin America

The author seeks to analyse the relationships between religion and culture in Latin America, especially in Brazil, highlighting the fact that the different religions enjoy diverse relationships with culture in a single location. He also addresses the fact that religions interpret culture in different ways and these interpretations help define their conversion strategies and how best to confront opposing religions. For the sake of discussion, the author considers, hypothetically, a not-so-distant future in which Latin America becomes predominantly evangelical, and asks what will happen to Latin America`s supposed Catholic culture if the evangelical religions do indeed take over.

Bladder irrigation with amphotericin B and fungal urinary tract infection-systematic review with meta-analysis

Background: Candiduria is a hospital-associated infection and a daily problem in the intensive care unit. The treatment of asymptomatic candiduria is not well established and the use of amphotericin B bladder irrigation (ABBI) is controversial. The aim of this systematic review was to determine the best place for this therapy in practice. Methods: The databases searched in this study included MEDLINE, EMBASE, Web of Science, and LILACS (January 1960-June 2007). We included manuscripts with data on the treatment of candiduria using ABBI. The studies were classified as comparative, dose-finding, or non-comparative. Results: From 213 studies, nine articles (377 patients) met our inclusion criteria. ABBI showed a higher clearance of the candiduria 24 hours after the end of therapy than fluconazole (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.32-1.00). Fungal culture 5 days after the end of both therapies showed a similar response (OR 1.51, 95% CI 0.81-2.80). The evaluation of ABBI using an intermittent or continuous system of delivery showed an early candiduria clearance (24 hours after therapy) of 80% and 82%, respectively (OR 0.87, 95% CI 0.52-1.36). Candiduria clearance at >5 days after the therapy showed a superior response using continuous bladder irrigation with amphotericin B (OR 0.52, 95% CI 0.29-0.94). The use of continuous ABBI for more than 5 days showed a better result (88% vs. 78%) than ABBI for less than 5 days, but without significance (OR 0.55, 95% CI 0.34-1.04). Conclusion: Although the strength of the results in the underlying literature is not sufficient to allow the drawing of definitive conclusions, ABBI appears to be as effective as fluconazole, but it does not offer systemic antifungal therapy and should only be used for asymptomatic candiduria. (C) 2008 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Infection rate and risk factors associated with infections related to external ventricular drain

To describe incidence rates and risk factors associated with external ventricular drain (EVD)-related infections at a tertiary Brazilian teaching hospital. The patient cohort consisted of all patients at a major teaching hospital in Brazil with an EVD during the period 1 April 2007 to 30 June 2008 (15 months). Patients were followed up for 30 days after catheter removal. According to the Center for Diseases Control and Prevention criteria for meningitis/ventriculitis, all of the central nervous system (CNS) infections that occurred during this period could be considered to be meningitis or ventriculitis related to EVD placement. Infection rates were calculated using different denominators, such as (1) per patient (incidence), (2) per procedure, and (3) per 1,000 catheter-days (drain-associated infection rate). Patient demographic data, medical history of underlying diseases, antibiotic prophylaxis usage, American Society of Anesthesiologists Score classification, duration of surgery and hospitalization, length of time the EVD was in place, and overall mortality were evaluated during the study period. A logistic regression model was developed to identify factors associated with infection. A total of 119 patients, 130 EVD procedures, and 839 catheter-days were evaluated. The incidence of infection was 18.3%, the infection rate was 16.9% per procedure, and the drain-associated infection rate was 22.4 per 1,000 catheter-days; 77% of the infections were caused by Gram-negative micro-organisms. Only 75% of patients received antibiotic prophylaxis. The infection rate increased with length of the hospital stay. The length of time the catheter was in place was the only independent risk factor associated with infection (p = 0.0369). The incidence of EVD-related infections is high in our hospital, Gram-negative micro-organisms were the most frequent causal agents identified and length of time that the catheter was in place contributed to the infection rate.

Is procalcitonin useful to differentiate rejection from bacterial infection in the early post-operative period of liver transplantation in children?

PCT is a protein that is recognized as an acute marker of inflammation. Previous studies performed in adults who underwent liver or heart transplantation indicated that PCT plasmatic levels help to differentiate between rejection and infection. The objective of this study was to evaluate whether PCT has the same role in liver-transplanted children. Thirty-six patients were studied between the first and the thirtieth post-operative days, and PCT determinations were prospectively performed according to the clinical status of the patient. In the non-complicated patients, PCT measurements performed on the first and second post-operative days revealed a median value of 1.60 ng/mL (mean 5.68 +/- 7.05; range 0.69-18.30). After the fourth day of transplantation, PCT plasma concentrations decreased to a median value of 0.21 ng/mL (mean 0.47 +/- 0.59; range 0.05-2.00; normal values are less than 0.5 ng/mL). In infected patients, PCT plasma levels demonstrated a significant increase, differing from the patients with acute liver rejection whose levels were similar to those of non-complicated patients. In conclusion, we could demonstrate that in the early post-operative period of liver transplantation in children, measuring PCT plasmatic levels might be a useful tool for differentiation between bacterial infection and acute liver rejection.

Peptides containing T cell epitopes, derived from Sm14, but not from paramyosin, induce a Th1 type of immune response, reduction in liver pathology and partial protection against Schistosoma mansoni infection in mice

Sm14 and paramyosin are two major Schistosoma mansoni vaccine candidate antigens. Recently, we have identified Sm14 and paramyosin epitopes that are recognized by T cells of resistant individuals living in endemic areas for schistosomiasis. Herein, mice were immunized with these peptides separately or in association in order to evaluate their vaccine potential. Immunization of mice with Sm14 peptides alone or mixed with paramyosin peptides was able to induce 26%-36.7% or 28%-29.2% of worm burden reduction, 67% or 46% of intestinal eggs reduction and also 54%-61% or 43%-52% of liver pathology reduction, respectively. Protection was associated with a Th1 type of immune response induced by Sm14 peptide immunization. In contrast, paramyosin peptide vaccination did not engender protective immunity or liver pathology reduction and immunization was associated with a Th2 type of immune response. (C) 2008 Elsevier B.V. All rights reserved.

Cutaneous Mycobacterium haemophilum infection in a kidney transplant recipient after acupuncture treatment

P>Mycobacterium haemophilum is a slow-growing nontuberculous mycobacterium that can cause disease in both immunocompetent and immunocompromised patients. The most common clinical presentations of infection are the appearance of suppurative and ulcerated skin nodules. For the diagnosis, samples collected from suspected cases must be processed under the appropriate conditions, because M. haemophilum requires lower incubation temperatures and iron supplementation in order to grow in culture. In this case report, we describe the occurrence of skin lesions in a kidney transplant recipient, caused by M. haemophilum, associated with acupuncture treatment. The diagnosis was established by direct smear and culture of material aspirated from cutaneous lesions. Species identification was achieved by characterization of the growth requirements and by partial sequencing of the hsp65 gene. The patient was successfully treated with clarithromycin and ciprofloxacin for 12 months. Considering that the number of patients receiving acupuncture treatment is widely increasing, the implications of this potential complication should be recognized, particularly in immunosuppressed patients.

Galectin-3 plays a modulatory role in the life span and activation of murine neutrophils during early Toxoplasma gondii infection

Galectins are beta-galactoside-binding lectins involved in several biological processes and galectin-3 (Gal-3) is related to modulation of immune and inflammatory responses. This study aimed to evaluate the role of Gal-3 in the life span and biological functions of murine neutrophils during in vitro infection by virulent Toxoplasma gondii RH strain. Inflammatory peritoneal neutrophils (N phi) from C57BL/6 wildtype (WT) and Gal-3 knockout (KO) mice were cultured in the presence or absence of parasites and analyzed for phosphatidylserine (PS) exposure and cell death using Annexin-V and propidium iodide staining, and cell viability by MU assay. Cell toxicities determined by lactate dehydrogenase (LDH), degranulation by lysozyme release, and cytokine production were measured in NO culture supernatants. Phorbol myristate acetate (PMA)- or zymosan-dependent reactive oxygen species (ROS) were measured in N phi cultures. Our results demonstrated that Gal-3 is involved in the increase of the viable Not. number and the decrease of PS exposure and cell death following T. gondii infection. We also observed that Gal-3 downmodulates gondii-induced N phi toxicity as well as N phi degranulation regardless of infection. Furthermore, Gal-3 expression by N phi was associated with increased levels of IL-10 in the beginning and decreased levels of TNF-alpha later on, regardless of parasite infection, as well as with decreased levels of IL-6 and increased IL-12 levels, following early parasite infection. Our results also showed that Gal-3 suppresses PMA- but not zymosan-induced ROS generation in N phi following T. gondii infection. In conclusion, Gal-3 plays an important modulatory role by interfering in N phi life span and activation during early T gondii infection. (C) 2009 Elsevier GmbH. All rights reserved.

Lack of galectin-3 alters the balance of innate immune cytokines and confers resistance to Rhodococcus equi infection

Galectin-3 is a p-galactoside-binding lectin implicated in the fine-tuning of innate immunity. Rhodococcus equi, a facultative intracellular bacterium of macrophages, causes severe granulomatous bronchopneumonia in young horses and immunocompromised humans. The aim of this study is to investigate the role of galectin-3 in the innate resistance mechanism against R. equi infection. The bacterial challenge of galectin-3-deficient mice (gal3(-/-)) and their wild-type counterpart (gal3(+/+)) revealed that the LD50 for the gal3(-/-) mice was about seven times higher than that for the gal3(+/+) mice. When challenged with a sublethal dose, gal3(-/-) mice showed lower bacteria counts and higher production of IL-12 and IFN-gamma production, besides exhibiting a delayed although increased inflammatory reaction. Gal3(-/-) macrophages exhibited a decreased frequency of bacterial replication and survival, and higher transcript levels of IL-1 beta, IL-6, IL-10, TLR2 and MyD88. R. equi-infected gal3(+/+) macrophages showed decreased expression of TLR2, whereas R. equi-infected gal3(-/-) macrophages showed enhanced expression of this receptor. Furthermore, galectin-3 deficiency in macrophages may be responsible for the higher IL-1 beta serum levels detected in infected gal3(-/-) mice. Therefore galectin-3 may exert a regulatory role in innate immunity by diminishing IL-1 beta production and thus affecting resistance to R. equi infection.

Phylogenetic Analysis of Hepatitis B Virus Genotype F Complete Genome Sequences From Chilean Patients With Chronic Infection

Molecular epidemiological data concerning the hepatitis B virus (HBV) in Chile are not known completely. Since the HBV genotype F is the most prevalent in the country, the goal of this study was to obtain full HBV genome sequences from patients infected chronically in order to determine their subgenotypes and the occurrence of resistance-associated mutations. Twenty-one serum samples from antiviral drug-naive patients with chronic hepatitis B were subjected to full-length PCR amplification, and both strands of the whole genomes were fully sequenced. Phylogenetic analyses were performed along with reference sequences available from GenBank (n = 290). The sequences were aligned using Clustal X and edited in the SE-AL software. Bayesian phylogenetic analyses were conducted by Markov Chain Monte Carlo simulations (MCMC) for 10 million generations in order to obtain the substitution tree using BEAST. The sequences were also analyzed for the presence of primary drug resistance mutations using CodonCode Aligner Software. The phylogenetic analyses indicated that all sequences were found to be the HBV subgenotype F1b, clustered into four different groups, suggesting that diverse lineages of this subgenotype may be circulating within this population of Chilean patients. J. Med. Virol. 83: 1530-1536, 2011. (C) 2011 Wiley-Liss, Inc.