Degradation of gasoline aromatic hydrocarbons by two N2-fixing soil bacteria

Two bacterial strains, 3A and 5A, isolated from soil, were selected for their ability to degrade gasoline aromatic compounds and to fix N₂. Strains 3A and 5A have been ascribed to the genera Agrobacterium and Alcaligenes, respectively. Using gasoline as the sole carbon source these strains were as effective at degrading benzene, toluene and xylene as Pseudomonas putida ATCC12236, a reference biodegrading strain.     

Tree dominance and diversity in Minas Gerais,Brazil

Quantifying diversity is an old challenge for ecologists and is also a social demand given the increasing threats to natural areas. We sought to work on these issues by using data from 158 vegetation remnants (over 350,000 trees) in southeastern Brazil (Minas Gerais State—MG, nearly 600,000 km²). Specifically, we sought to answer the following questions. (1) How many trees and tree species currently exist in MG vegetation remnants? (2) How much of such biodiversity is present in each vegetation domain (Atlantic Forest, Cerrado and Caatinga) and vegetation type (Seasonally Dry tropical forest “semideciduous”, Seasonally Dry tropical forest “deciduous”, Rain Forest, Swamp, Cerrado and Cerradão) in MG? (3) How much has been lost in regards to tree amount and tree species? We built a 0.1-degree cell grid to estimate the number of trees via spatial regression and used Fisher’s alpha and Fisher’s log series to provide estimates on how many tree species there are and were in MG. We found the number of trees in Minas Gerais to be approximately 24.5 × 10⁹, and the number of tree species to be between 3592 and 3743. The most abundant species distribution among the vegetation domains and vegetation types followed inversely the environmental heterogeneity of the classes. Consequently, the most abundant species in MG belonged to the Cerrado domain, where there was less environmental heterogeneity. The numbers of trees and tree species lost were estimated at 68.54 and 4.03–8.42% of the original values, respectively. We discuss that due to the consequences of human impacts that go back in the region for over a thousand years, other processes not considered in this study, such as habitat degradation by isolation, alterations of food webs, unsustainable use, and climate change, might have caused local extinctions and potentially increased the number of species lost. We believe our results may guide conservation initiatives by providing a base for future environmental laws, parks planning, and the development of more appropriate vegetation management techniques in MG. In addition, our results may inspire future quantitative ecological studies in the tropics.     

Influence of shading and pedestrian traffic on the preference of Aedes (Stegomyia) aegypti (Diptera: Culicidae) for oviposition microenvironments

Aedes aegypti mosquitoes are highly adaptable to abiotic stimuli. To evaluate the influence of shading and pedestrian traffic on the preference of Ae. aegypti for oviposition microenvironments, 20 sites were sampled weekly using ovitraps within the perimeter of Universidade Federal do Espírito Santo, located in São Mateus, Espírito Santo, Brazil. A spatial and statistical analysis was performed in order to assess the relationship between shading time, pedestrian traffic, and the presence of biological forms of Ae. aegypti. A temporal analysis of temperature and precipitation influence on oviposition was also made. Between June, 2013 and June, 2014, 7,362 Ae. aegypti eggs were collected. Over a 12‐month period, we made weekly collections of Ae. aegypti eggs from ovitraps. Pedestrian traffic and shading time influenced the number of positive ovitraps; precipitation and temperature were correlated with the number of positive ovitraps (p <0.05). We conclude that the influence of temperature and precipitation was not significant for the oviposition index, and the frequency of oviposition was directly proportional to the number of individuals moving close to the traps during periods of greater shading.     

Evolutionarily significant units of the critically endangered leaf frog Pithecopus ayeaye (Anura,Phyllomedusidae) are not effectively preserved by the Brazilian protected areas network

Protected areas (PAs) are essential for biodiversity conservation, but their coverage is considered inefficient for the preservation of all species. Many species are subdivided into evolutionarily significant units (ESUs) and the effectiveness of PAs in protecting them needs to be investigated. We evaluated the usefulness of the Brazilian PAs network in protecting ESUs of the critically endangered Pithecopus ayeaye through ongoing climate change. This species occurs in a threatened mountaintop ecosystem known as campos rupestres. We used multilocus DNA sequences to delimit geographic clusters, which were further validated as ESUs with a coalescent approach. Ecological niche modeling was used to estimate spatial changes in ESUs’ potential distributions, and a gap analysis was carried out to evaluate the effectiveness of the Brazilian PAs network to protect P. ayeaye in the face of climate changes. We tested the niche overlap between ESUs to gain insights for potential management alternatives for the species. Pithecopus ayeaye contains at least three ESUs isolated in distinct mountain regions, and one of them is not protected by any PA. There are no climatic niche differences between the units, and only 4% of the suitable potential area of the species is protected in present and future projections. The current PAs are not effective in preserving the intraspecific diversity of P. ayeaye in its present and future range distributions. The genetic structure of P. ayeaye could represent a typical pattern in campos rupestres endemics, which should be considered for evaluating its conservation status.     

PCR-fingerprinting and RAPD approaches for tracing the source of yeast contamination in a carbonated orange juice production chain

AIMS: To investigate the sort and the origin of the contamination of a packed fruit juice. METHODS AND RESULTS: Fifty-eight yeast isolates were collected in a survey of two different visits to a carbonated orange juice factory. In each visit, samples were collected, six times, from seven points in the production chain. For each visit, no significant differences were observed among the yeast average values obtained in the control points considered. The random amplified polymorphic DNA (RAPD) with primer P24 and the PCR-fingerprinting with the microsatellites primers (GTG)5 and (GAC)5 were used, in order to discriminate the isolates, rendering 29 composite profiles; the most frequent one (24/58) was profile c, which included the yeast isolates from the final product and strains isolated before and after the pasteurization of the juice. These contaminant strains were identified as Pichia galeiformis by sequence analysis of D1/D2 26S rRNA gene. CONCLUSIONS: The results obtained point to an inefficient pasteurization of the juice related to the fouling of the heat-transfer surfaces of the plate-type exchanger. SIGNIFICANCE AND IMPACT OF THE STUDY: The combination of PCR-fingerprinting and RAPD assays showed to be very useful in tracking the route of contamination in a carbonated juice production chain.     

Dendritic cells derived from metastatic cancer patients vaccinated with allogeneic dendritic cell–autologous tumor cell hybrids express more CD86 and induce higher levels of interferon-gamma in mixed lymphocyte reactions

Dendritic cells (DCs) are highly effective antigen-presenting cells that, when derived from cancer patients, seem to be functionally deficient. Herein, we show that vaccination with allogeneic DC–autologous tumor cell hybrids affects the phenotype and improves the function of monocyte-derived DCs (Mo-DCs) from cancer patients. Mononuclear cells were isolated from patients peripheral blood by density gradient centrifugation, and adherent cells were cultured in medium containing GM-CSF plus IL-4 and, after 5 days, TNF-. After 2 more days, Mo-DCs were harvested and their CD80, CD86, and CD83 expression was assessed by flow cytometry. They were also used as stimulators in mixed lymphocyte reactions (MLR), where IFN- production was measured by ELISA. Mo-DCs from unvaccinated patients expressed significantly lower levels of CD86, and tended to express lower levels of CD83 than Mo-DCs from healthy donors. However, Mo-DCs generated after hybrid cell vaccination presented increased expression of the same markers and induced significantly higher levels of IFN- in MLR. These results indicate that the use of allogeneic DC–based cancer vaccines induces recovery of DC function in metastatic cancer patients and, therefore, could precede the use of autologous DCs for vaccine preparation. Such an approach could be relevant and should be investigated in clinical trials.     

A comparison of mycolic acid analysis for nontuberculous mycobacteria identification by thin-layer chromatography and molecular methods

The development of fast, inexpensive, and reliable tests to identify nontuberculous mycobacteria (NTM) is needed. Studies have indicated that the conventional identification procedures, including biochemical assays, are imprecise. This study evaluated a proposed alternative identification method in which 83 NTM isolates, previously identified by conventional biochemical testing and in-house M. avium IS1245-PCR amplification, were submitted to the following tests: thin-layer chromatography (TLC) of mycolic acids and PCR-restriction enzyme analysis of hsp65(PRA). High-performance liquid chromatography (HPLC) analysis of mycolic acids and Southern blot analysis for M. avium IS1245 were performed on the strains that evidenced discrepancies on either of the above tests. Sixty-eight out of 83 (82%) isolates were concordantly identified by the presence of IS1245 and PRA and by TLC mycolic acid analysis. Discrepant results were found between the phenotypic and molecular tests in 12/83 (14.4%) isolates. Most of these strains were isolated from non-sterile body sites and were most probably colonizing in the host tissue. While TLC patterns suggested the presence of polymycobacterial infection in 3/83 (3.6%) cultures, this was the case in only one HPLC-tested culture and in none of those tested by PRA. The results of this study indicated that, as a phenotypic identification procedure, TLC mycolic acid determination could be considered a relatively simple and cost-effective method for routine screening of NTM isolates in mycobacteriology laboratory practice with a potential for use in developing countries. Further positive evidence was that this method demonstrated general agreement on MAC and M. simiae identification, including in the mixed cultures that predominated in the isolates of the disseminated infections in the AIDS patients under study. In view of the fact that the same treatment regimen is recommended for infections caused by these two species, TLC mycolic acid analysis may be a useful identification tool wherever molecular methods are unaffordable.