Patterns of genetic diversity in southern and southeastern Araucaria angustifolia (Bert.) O. Kuntze relict populations

Habitat fragmentation and a decrease in population size may lead to a loss in population genetic diversity. For the first time, the reduction in genetic diversity in the northernmost limit of natural occurence (southeastern Brazil) of Araucaria angustifolia in comparison with populations in the main area of the species continuous natural distribution (southern Brazil), was tested. The 673 AFLPs markers revealed a high level of genetic diversity for the species (Ht = 0.27), despite anthropogenic influence throughout the last century, and a decrease of H in isolated populations of southeastern Brazil (H = 0.16), thereby indicating the tendency for higher genetic diversity in remnant populations of continuous forests in southern Brazil, when compared to natural isolated populations in the southeastern region. A strong differentiation among southern and southeastern populations was detected (AMOVA variance ranged from 10%-15%). From Bayesian analysis, it is suggested that the nine populations tested form five "genetic clusters" (K = 5). Five of these populations, located in the northernmost limit of distribution of the species, represent three "genetic clusters". These results are in agreement with the pattern of geographic distribution of the studied populations.     

Acute exercise boosts cell proliferation and the heat shock response in lymphocytes: correlation with cytokine production and extracellular-to-intracellular HSP70 ratio

Exercise stimulates immune responses, but the appropriate “doses” for such achievements are unsettled. Conversely, in metabolic tissues, exercise improves the heat shock (HS) response, a universal cytoprotective response to proteostasis challenges that are centred on the expression of the 70-kDa family of intracellular heat shock proteins (iHSP70), which are anti-inflammatory. Concurrently, exercise triggers the export of HSP70 towards the extracellular milieu (eHSP70), where they work as pro-inflammatory cytokines. As the HS response is severely compromised in chronic degenerative diseases of inflammatory nature, we wondered whether acute exercise bouts of different intensities could alter the HS response of lymphocytes from secondary lymphoid organs and whether this would be related to immunoinflammatory responses. Adult male Wistar rats swam for 20 min at low, moderate, high or strenuous intensities as per an overload in tail base. Controls remained at rest under the same conditions. Afterwards, mesenteric lymph node lymphocytes were assessed for the potency of the HS response (42 °C for 2 h), NF-κB binding activity, mitogen-stimulated proliferation and cytokine production. Exercise stimulated cell proliferation in an “inverted-U” fashion peaking at moderate load, which was paralleled by suppression of NF-κB activation and nuclear location, and followed by enhanced HS response in relation to non-exercised animals. Comparative levels of eHSP70 to iHSP70 (H-index) matched IL-2/IL-10 ratios. We conclude that exercise, in a workload-dependent way, stimulates immunoinflammatory performance of lymphocytes of tissues far from the circulation and this is associated with H-index of stress response, which is useful to assess training status and immunosurveillance balance.     

MODULAR: software for the autonomous computation of modularity in large network sets

Many ecological systems can be represented as networks of interactions. A key feature in these networks is their organization into modules, which are subsets of tightly connected elements. We introduce MODULAR to perform rapid and autonomous calculation of modularity in network sets. MODULAR reads a set of files representing unipartite or bipartite networks, and identifies modules using two different modularity metrics widely used in the ecological networks literature. To estimate modularity, the software offers five optimization methods to the user. The software also includes two null models commonly used in studies of ecological networks to verify how the degree of modularity differs from two distinct theoretical benchmarks.     

Susceptibility of different populations of ticks to entomopathogenic fungi

This study aimed to evaluate the in vitro effect of the entomopathogenic fungi Metarhizium anisopliae sensu lato (s.l.) and Beauveria bassiana sensu lato (s.l.) on two distinct populations of Rhipicephalus microplus, from two different experimental farms. Bioassays were performed with engorged females, eggs and larvae. Fungal infection was evaluated based on biological parameters of treated engorged females, percentage of hatch from treated eggs, and percentage of mortality and mean lethal time (LT90) of treated larvae. When the treatments were compared between the two populations, there were significant differences in the following parameters: pre-oviposition period, hatching period and egg production index. Moreover, the results showed that B. bassiana s.l., isolate Bb 986, was more virulent than M. anisopliae s.l., isolate 959, for engorged females, showing a control percentage of 49%. In the bioassay with eggs, the hatching percentage ranged from 3.1% to 49.5% in one population and from 3.4% to 42.7% in the other, with no significant difference between the two populations. In the bioassay with unfed larvae, the mortality percentage ranged from 91.8% to 98.7% in one population and from 71.0% to 94.0% in the other. The LT(90) varied from 19.52 to 27.51 days in one of the populations and 22.89 to 37.31 days in the other. These results suggest that populations of R. microplus show distinct variation in their susceptibility to B. bassiana s.l. and M. anisopliae s.l.     

Comparison Between Etest and Broth Microdilution Methods for Testing Itraconazole-Resistant <Emphasis Type="Italic">Aspergillus fumigatus</Emphasis> Susceptibility to Antifungal Combinations

The checkerboard broth microdilution assay (BMD) is the most frequently used method for the in vitro evaluation of drug combinations. However, its use to evaluate the effect of antifungal drugs on filamentous fungi is sometimes associated with endpoint-reading difficulties, and different degrees of interaction are assigned to the same drug combination. We evaluated combinations of the azoles, itraconazole, posaconazole, and voriconazole, with the echinocandins, anidulafungin, caspofungin, and micafungin, against 15 itraconazole-resistant Aspergillus fumigatus clinical strains via the checkerboard BMD and Etest assay. Readings after 24 and 48 h, considering the two reading endpoints, the minimum inhibitory concentration (MIC) and minimum effective concentration (MEC), were performed for both methods. Our results showed that the correlation coefficients between the BMD and Etest methods were quite diverse to the drug combinations tested. The highest correlation coefficients of the Etest with the BMD assays (MEC and MIC reading) were the Etest-MIC reading at 24 h and the Etest-MEC reading at 48 h. Improvements in experimental conditions may increase the correlation between the two methods and ensure that Etest assay can be safely used in the evaluation of antifungal combinations against Aspergillus species.     

Using genetic diversity and mating system parameters estimated from genetic markers to determine strategies for the conservation of <Emphasis Type="Italic">Araucaria angustifolia</Emphasis> (Bert.) O. Kuntze (Araucariaceae)

In order to understand the impacts of forest fragmentation on Araucaria angustifolia populations, we evaluated the genetic diversity and mating system using SSR markers and open-pollinated seeds from four populations of varying sizes and spatial isolation, in and around one of the best-conserved Araucaria Forest remnants in Southern Brazil. The four population types of A. angustifolia include: (1) a continuous forest; (2) a physically isolated cluster located 2 km from the continuous forest; (3) an open population in a field located between the cluster and continuous forest; and (4) a fragment on a private property located 5 km from the cluster. Approximately 28 seeds were collected from ten reproductive trees in each population. We found higher amounts of alleles (113) and exclusive alleles (25) in the continuous forest than in the other populations. The multilocus paternity correlation was significantly higher and effective number of pollen donors was significantly lower in the private population, decreasing the diversity and consequently the variance effective size of families sampled from that population. However, despite its isolation from the other studied fragments, the private population had the second highest number of alleles as well as unique alleles from the other populations. Therefore, strategies for A. angustifolia conservation should focus not only on larger populations, such as those found in protected areas, but also include smaller and isolated fragments on private properties as these populations are able to maintain high levels of genetic diversity and functional connectivity between isolated stands across a landscape.     

Steady state kinetics and effect of SH inhibitors on acid phosphatase from bovine brain.

1. Product inhibition studies and transphosphorylation to methanol using two different substrates indicate that acid phosphatase from bovine brain forms a phosphoryl enzyme and that the phosphorylation step can not be rate limiting. 2. Acid phosphatase from bovine brain is inhibited by 5,5'-dithiobis-(2-nitrobenzoic acid); this inhibition can be counteracted by inorganic phosphate. Incubation of the enzyme with p-nitrophenyl phosphate in the presence of p-chloromercuribenzoate leads, initially, to a higher degree of inhibition than that found with the same concentration of inhibitor in the absence of substrate. Both the titration by 5,5'-dithiobis-(2-nitrobenzoic acid) and inhibition by p-chloromercuribenzoate are consistant with the presence of 2 SH groups per mol of enzyme.     

Paracoccidioidomycosis in a four-year-old boy

Summary A case of fatal, generalized paracoccidioidomycosis is described in a four-year-old urban dwelling child. Marked lympadenopathy, hepatosplenomegaly and an abdominal mass were the main clinical manifestations. The diagnosis was established by histopathological studies and culture. The authors comment on the rarity of this infection in children less than 7 years of age and on the importance of considering this pathology in the differential diagnosis of malignant non-Hodgkin lymphoma and tuberculosis, in children.Medical Student of the Federal University of Bahia.     

Selecting a Hiding Place: Anuran Diversity and the use of Bromeliads in a Threatened Coastal Sand Dune Habitat in Brazil

Among vertebrates, anuran amphibians represent the highest number of species associated with bromeliads and possess a range of ecological, behavioral, and morphological specializations to life in these plants. Despite the importance of bromeliads as biodiversity amplifiers, and their diversity in some habitats, studies of the relationship between anurans and these plants are scarce in Brazil. Here, we investigated the way anurans select and use bromeliads in a threatened coastal habitat. We analyzed data from 23 standardized samples of the anurans associated with the bromeliad Neoregelia cruenta in the Restinga de Maricá, State of Rio de Janeiro, Southeastern Brazil. We found nine anuran species using these bromeliads, representing the highest richness reported for a Brazilian restinga. We identified a general pattern of bromeliad usage, where plants located at the edges of scrub patches (exposed to the sun) were more frequently occupied by anurans than those located more to the center (in the shade). There is strong evidence of an active selective process based on the quality of the water stored in the rosette, which differs between plants depending on their position in the scrub patch. Although the number of individuals varied during the period of study, the frequency of bromeliads used was constant, indicating that plant occupation follows a regular pattern throughout the year. Furthermore, the high frequency of bromeliads used by anurans during the whole year highlights the importance of considering these plants in developing conservation programs concerning the protection of anurans.     

Dimethylacetamide alone or in combination with glycerol can be used for cryopreservation of ovine semen

Dimethylacetamide has been included in different extenders for the cryopreservation of semen from species with promising results. The objective of this study was to evaluate the use of dimethylacetamide (DMA) in different concentrations, associated or not with glycerol (GLY), for the cryopreservation of ovine semen, and its effects on in vitro sperm parameters and post-thaw in vivo fertility. Five semen samples of five adult Santa Ines sheep (n=25) were used. The collected ejaculates were divided among the seven treatments for subsequent cryopreservation. The treatments presented different concentrations of DMA and GLY, being divided as G1: GLY 6%; G2: DMA 3%; G3: GLY 5% + DMA 1%; G4: GLY 4% + DMA 2%; G5: GLY 3% + DMA 3%; G6: GLY 2% + DMA 4%; G7: GLY 1% + DMA 5%. %. Post-thawing of the straws, aliquots were evaluated for computerized sperm kinetics (CASA) and plasma membrane integrity, using fluorescent probes and flow cytometry. After the in vitro evaluation of the sperm parameters, in vivo testing was performed by laparoscopic artificial insemination of 72 females. The post-thaw total motility (%) evaluated by CASA were 51.4, 51.4, 50.1, 53.6, 52.3, 52.8 and 46.9, respectively, for the seven groups. And the plasma membrane integrity (%) were 19.7, 28.4, 22.3, 29.4, 24.3, 17.9 and 16.9, respectively. There were no differences (P> 0.05) between the treatments for the parameters of spermatic kinetics and membrane integrity. For females inseminated with semen from the control group (G1, GLY6%), the percentage of pregnant females was 36.1%, a result similar to that obtained with G3 treatment (GLY5% + DMA1%). In conclusion, dimethylacetamide, either alone or in combination with glycerol, can be used for cryopreservation of ovine semen.