Bacterial structure and characterization of plant growth promoting and oil degrading bacteria from the rhizospheres of mangrove plants

Most oil from oceanic spills converges on coastal ecosystems, such as mangrove forests, which are threatened with worldwide disappearance. Particular bacteria that inhabit the rhizosphere of local plant species can stimulate plant development through various mechanisms; it would be advantageous if these would also be capable of degrading oil. Such bacteria may be important in the preservation or recuperation of mangrove forests impacted by oil spills. This study aimed to compare the bacterial structure, isolate and evaluate bacteria able to degrade oil and stimulate plant growth, from the rhizospheres of three mangrove plant species. These features are particularly important taking into account recent policies for mangrove bioreme-diation, implying that oil degradation as well as plant maintenance and health are key targets. Fifty-seven morphotypes were isolated from the mangrove rhizospheres on Bushneil-Haas (BH) medium supplemented with oil as the sole carbon source and tested for plant growth promotion. Of this strains, 60% potentially fixed nitrogen, 16% showed antimicrobial activity, 84% produced siderophores, 51% had the capacity to solubilize phosphate, and 33% produced the indole acetic acid hormone. Using gas chromatography, we evaluated the oil-degrading potential of ten selected strains that had different morphologies and showed Plant Growth Promoting Rhizobacteria (PGPR) features. The ten tested strains showed a promising degradation profile for at least one compound present in the oil. Among degrader strains, 46% had promising PGPR potential, having at least three of the above capacities. These strains might be used as a consortium, allowing the concomitant degradation of oil and stimulation of mangrove plant survival and maintenance.     

What Role Should Government Regulation Play in Ecological Restoration? Ongoing Debate in São Paulo State,Brazil

Around the world, there is growing desire and momentum for ecological restoration to happen faster, with better quality, and in more extensive areas. The question we ask is how can laws and governmental regulations best contribute to effective, successful, and broad‐scale restoration? In the state of São Paulo, Brazil, there is a legal instrument (SMA 08‐2008) whose aim is to increase the effectiveness of tropical forest restoration projects in particular. It establishes, among other things, requirements regarding the minimum number of native tree species to be reached within a given period of time in restoration projects and the precise proportion of functional groups or threatened species to be included when reforestation with native species is used as a restoration technique. There are, however, two differing perspectives among Brazilian restoration ecologists on the appropriateness of such detailed legal rules. For some, the rules help increase the chances that mandatory projects of ecological restoration will succeed. For the other group, there is no single way to achieve effective ecosystem restoration, and the existing science and know‐how are far from sufficient to establish standardized technical and methodological norms or to justify that such norms be imposed. Both points of view are discussed here, aiming to help those developing new legislation and improving existing laws about ecological restoration. The precedents established in São Paulo, and at the federal level in Brazil, and the ongoing debate about those laws are worth considering and possibly applying elsewhere.     

Effects of the utilization of homeopathic elements in commercial diluent on swine sperm viability

It has been speculated that the homeopathic treatment of sperm cells in order to improve semen quality could be promising. However, few data is available and its use in spermatozoa requires investigation. It is well established that mitochondrial membrane potential is an important viability parameter of spermatozoa and it is intimately related to reproductive efficiency. In this manner, new technologies in order to improve the activity of sperm cells and, finally, the fecundity of swine herds are of extremely importance. Due to the lack of knowledge of homeopathic treatment effect on spermatozoa, the aim of the present study was to verify the effect of three different homeopathic treatments on viability of boar sperm cells. Three homeopathic treatments composed by Pulsatila CH6, Pulsatila and Avena CH6, Avena CH6 and one control treatment (sucrose) were added to diluted boar semen, which were cooled for 24 or 48 h. Interestingly, no positive effect of homeopathic treatments was observed over semen viability. However, it was demonstrated that the 24 h of cooling storage provided more viable sperm cells when compared to the 48-h period. This effect of storage period on sperm viability was assessed by intact plasmatic membrane, intact acrosome and mitochondrial membrane potential evaluation.     

Modelling survival and allele complementation in the evolution of genomes with polymorphic loci

We have simulated the evolution of sexually reproducing populations composed of individuals represented by diploid genomes. A series of eight bits formed an allele occupying one of 128 loci of one haploid genome (chromosome). The environment required a specific activity of each locus, this being the sum of the activities of both alleles located at the corresponding loci on two chromosomes. This activity is represented by the number of bits set to zero. In a constant environment the best fitted individuals were homozygous with alleles’ activities corresponding to half of the environment requirement for a locus (in diploid genome two alleles at corresponding loci produced a proper activity). Changing the environment under a relatively low recombination rate promotes generation of more polymorphic alleles. In the heterozygous loci, alleles of different activities complement each other fulfilling the environment requirements. Nevertheless, the genetic pool of populations evolves in the direction of a very restricted number of complementing haplotypes and a fast changing environment kills the population. If simulations start with all loci heterozygous, they stay heterozygous for a long time.     

Starvation and rapamycin differentially regulate host cell lysosome exocytosis and invasion by Trypanosoma cruzi metacyclic forms

The molecular mechanisms of host cell invasion by T. cruzi metacyclic trypomastigotes (MT), the developmental forms that initiate infection in the mammalian host, are only partially understood. Here we aimed at further identifying the target cell components involved in signalling cascades leading to MT internalization, and demonstrate for the first time the participation of mammalian target of rapamycin (mTOR). Treatment of human epithelial HeLa cells with mTOR inhibitor rapamycin reduced lysosomal exocytosis and MT invasion. Downregulation of phosphatidylinositol 3-kinase and protein kinase C also impaired exocytosis and MT internalization. The recombinant protein based on gp82, the MT surface molecule that mediates cell adhesion/invasion, induced exocytosis in HeLa cells. Such an effect has not previously been attributed to any T. cruzi surface molecule. Rapamycin treatment diminished gp82 binding as well. Cell invasion assays under conditions that promoted lysosome exocytosis, such as 1 h incubation in starvation medium PBS(++) , increased MT invasion, whereas pre-starvation of cells for 1-2 h had an opposite effect. In contrast to MT, invasion of tissue culture trypomastigotes (TCT) increased upon host cell pre-starvation or treatment with rapamycin, a novel finding that discloses quite distinctive features of the two infective forms in a key process for infection.     

Development and Evaluation of a Floating Multiparticulate Gastroretentive System for Modified Release of AZT

The aim of this study was to develop and evaluate a floating multiparticulate gastroretentive system for the modified release of zidovudine (AZT). AZT was used as a model drug water-soluble at therapeutic doses. The floating gastroretentive system was obtained by co-precipitation, after solvent diffusion and evaporation. The proposed system was evaluated in vitro for particle morphology, lag time and floating time, loading rate, release profile, and the release kinetic of AZT release. AZT’s physico-chemical characteristics were evaluated by differential scanning calorimetry (DSC), X-ray diffraction (XDR) and infrared spectroscopy (IR). The particles obtained were sphere-shaped, hollow, and had porous walls. The floating was immediate, and floating time was higher than 12 h. The loading rate was 34.0 ± 9.0%. The system obtained had an extended release. DSC and XDR results showed a modification in AZT’s solid state. IR spectroscopy revealed that the chemical structure of the AZT was unchanged. The hollow microballoons presented gastroretentive, floating, and extended-release properties.     

Genetic structure based on nuclear and chloroplast microsatellite loci of Solanum lycocarpum A. St. Hil. (Solanaceae) in Central Brazil

Solanum lycocarpum (Solanaceae) is a woody species found in the Brazilian Cerrado. The flowers are pollinated by Xylocopa spp bees, and seeds are dispersed by mammals with distinct home range sizes. As a consequence, relative contributions of pollen and seeds to overall gene flow can vary according to different spatial scales. We studied the genetic structure of four natural populations of S. lycocarpum separated by 19 to 128 km, including individuals located along dirt roads that interlink three of the populations. A total of 294 individuals were genotyped with five nuclear and six chloroplast microsatellite markers. Significant spatial genetic structure was found in the total set of individuals; the Sp statistic was 0.0086. Population differentiation based on the six chloroplast microsatellite markers (θ(pC) = 0.042) was small and similar to that based on the five nuclear microsatellite markers (θ(p) = 0.054). For this set of populations, pollen and seed flow did not differ significantly from one another (pollen-to-seed flow ratio = 1.22). Capability for long distance seed dispersion and colonization of anthropogenic sites contributes to the ability of S. lycocarpum to maintain genetic diversity. Seed dispersion along dirt roads may be critical in preserving S. lycocarpum genetic diversity in fragmented landscapes.     

Differential expression of genes during mastitis in Holstein-Zebu crossbreed dairy cows

Among the potential public health problems of animal production, infectious-contagious diseases stand out. Mastitis is among the main diseases affecting dairy cattle. One of the most promising options to reduce the problems caused by this disease, besides proper sanitary and management practices, is selective breeding of resistant animals. To shed light on the immune response mechanisms involved in the resistance/susceptibility phenotype to this disease, we quantified the relative expression of the genes IL-2, IL-6, IL-8, IL-12, IFN-γ, TNF-α, TLR-2, SEMA5A, and FEZL in cells of crossbreed dairy cows, divided into two groups, one healthy and the other suffering from clinical mastitis. Total RNA was extracted from the cells in the milk from the animals in each group (with and without clinical mastitis). Gene expression was determined using the real-time PCR method. The levels of gene expression were compared, and the cows with mastitis were found to express 2.5 times more TLR-2 than those free of mastitis (P < 0.05). There were no significant differences in the expression of the other genes.