Illumina sequencing-based analysis of a microbial community enriched under anaerobic methane oxidation condition coupled to denitrification revealed coexistence of aerobic and anaerobic methanotrophs

Methane is produced in anaerobic environments, such as reactors used to treat wastewaters, and can be consumed by methanotrophs. The composition and structure of a microbial community enriched from anaerobic sewage sludge under methane-oxidation condition coupled to denitrification were investigated. Denaturing gradient gel electrophoresis (DGGE) analysis retrieved sequences of Methylocaldum and Chloroflexi. Deep sequencing analysis revealed a complex community that changed over time and was affected by methane concentration. Methylocaldum (8.2%), Methylosinus (2.3%), Methylomonas (0.02%), Methylacidiphilales (0.45%), Nitrospirales (0.18%), and Methanosarcinales (0.3%) were detected. Despite denitrifying conditions provided, Nitrospirales and Methanosarcinales, known to perform anaerobic methane oxidation coupled to denitrification (DAMO) process, were in very low abundance. Results demonstrated that aerobic and anaerobic methanotrophs coexisted in the reactor together with heterotrophic microorganisms, suggesting that a diverse microbial community was important to sustain methanotrophic activity. The methanogenic sludge was a good inoculum to enrich methanotrophs, and cultivation conditions play a selective role in determining community composition.     

Mapping and evaluating sugarcane expansion in Brazil’s savanna using MODIS and intensity analysis: a case-study from the state of Tocantins

In Brazil, the main biofuel crop is sugarcane, and with its rapid expansion, there is much debate about what land uses and land covers it is replacing, and what are the associated environmental and social impacts. Some argue sugarcane is mainly replacing cattle pasture, thus having minimal impacts on native vegetation and small-scale family farming. In contrast, others claim sugarcane is replacing cropland traditionally under soybeans, rice, beans, and corn. Thus, food security is negatively affected and small-scale family farming livelihoods and culture are threatened. This is a proof-of-concept paper illustrating methods contributing toward the resolution of such debates. First we map land use and cover change in areas undergoing sugarcane expansion using satellite data from MODIS (Moderate Resolution Imaging Spectroradiometer); second, we test the hypothesis that sugarcane is replacing traditional annual crops using intensity analysis, via a case study of land change in the municipality of Pedro Afonso, Tocantins in northern Brazil between the 2008–2013 crop years. Maps matched reference data with overall agreements between 87–91%. Intensity analysis confirmed sugarcane is replacing annual crops much more than cattle pasture and other land uses and covers, pointing to particular economic and social processes driving land change.     

The Influence of Landscape Patterns on the Bird Diversity of Four Urban Parks

In our study, we aimed to investigate the influence of landscape patterns on the diversity of birds in four urban parks. The parks are located in a region that has a high value of regional biodiversity and is also highly urbanized (Jundiai, state of São Paulo [SP], in Southeastern Brazil). Using a set of aerial photos, the surrounding landscape was divided into two regions (rings) and corresponding landscape metrics were calculated. The presence of bird species was recorded monthly over a one‐year period and classified according to selected ecological criteria. The land cover of the areas surrounding each park was primarily buildings and residences. Bird diversity was significantly correlated with the presence/proximity of water bodies. We state that the potential of the parks to harbor bird species is not negligible. Managing the area surrounding a park to increase the percentage of forested area and the size of forest fragments is as crucial as managing the core park area, especially for improving its attractiveness for new bird species.     

Evidence for a significant contribution of wood burning aerosols to PM2.5 during the winter season in Paris,France

Although particulate emissions from residential wood burning have become a subject of great scientific concern for a few years, data related to their impact on the air quality of large European urban centres are still missing. In the present study, we investigated the chemical and optical properties of fine (PM_2.5) carbonaceous aerosols in Paris during the 2005 winter season in order to track the presence of wood burning emissions in such a large city. The use of a seven wavelength Aethalometer allowed us to document shortwave light absorption by brown-carbon-containing organic aerosols of biomass burning origin. In particular, a well-marked diurnal pattern of the spectral dependence of light absorption, with maxima during the night, could be observed every day of the campaign and attributed to wood burning emissions. Relatively high absorption Ångstrom exponents and WSOC/OC ratios (respectively 1.25 and 0.35 on average for the period of study) also indicated the importance of biomass burning aerosols in the Paris atmosphere in winter. Finally, a rough estimate of the contribution of wood burning carbonaceous aerosols to PM_2.5 could be achieved. This contribution was found to be as high as 20 ± 10% on average at the Paris background site investigated here.     

Extra-pair paternity in the monogamous Alpine marmot revealed by nuclear DNA microsatellite analysis

The genetic parentage and pedigrees of 35 litters from 12 family groups of monogamous Alpine marmot (Marmota marmota) in the French Alps were analyzed using six hypervariable sequence repeat nuclear loci (microsatellites). All of the members of these family groups were sampled during a 5-year period. Hairs taken directly from animals served as a source of DNA for amplification of the loci. Our results indicate that the genetic mating system of the Alpine marmot is quite different from a strictly monogamous breeding system. Extra-pair paternity occurred in 11 of the 35 litters (31.4%). Of the 134 juveniles typed, 26 (19.4%) could be attributed to extra-pair copulation (EPC). We examine hypotheses which could explain the evolution of EPC and discuss the different patterns of extra-pair mating. Received: 11 July 1997 / Accepted after revision: 23 May 1998     

Incest avoidance,fluctuating asymmetry,and the consequences of inbreeding in Iridomyrmex humilis,an ant with multiple queen colonies

Summary Inbreeding may have important consequences for the genetic structure of social insects and thus for sex ratios and the evolution of sociality and multiple queen (polygynous) colonies. The influence of kinship on mating preferences was investigated in a polygynous ant species, Iridomyrmex humilis, which has within-nest mating. When females were presented simultaneously with a brother that had been reared in the same colony until the pupal stage and an unrelated male produced in another colony, females mated preferentially with the unrelated male. The role of environmental colony-derived cues was tested in a second experiment where females were presented with two unrelated males, one of which had been reared in the same colony until the pupal stage (i.e., as in the previous experiment), while the other had been produced in another colony. In this experiment there was no preferential mating with familiar or unfamiliar males, suggesting that colony-derived cues might not be important in mating preferences. Inbreeding was shown to have no strong effect on the reproductive output of queens as measured by the number of worker and sexual pupae produced. The level of fluctuating asymmetry of workers produced by inbreeding queens was not significantly higher than that of non-inbreeding queens. Finally, colonies headed by inbreeding queens did not produce adult diploid males. Based on the current hypotheses of sex-determination the most plausible explanations for the absence of diploid-male-producing colonies are that (i) workers recognized and eliminated these males early in their development, and/or (ii) there are multiple sex-determining loci in this species. It is suggested that even if inbreeding effects on colony productivity are absent or low, incest avoidance mechanisms may have evolved and been maintained if inbreeding queens produce a higher proportion of unviable offspring. Correspondence to: L. Keller at the present address     

Metabolic fate of [14C]-2,4-dichlorophenol in macrophytes

The metabolic fate of 2,4-dichlorophenol (DCP) was investigated in six macrophytes representing different life forms. Salvinia natans and Lemna minor were chosen as surface-floating plants, Glyceria maxima and Mentha aquatica as emergent species and Myriophyllum spicatum and Hippuris vulgaris as submerged aquatic plants. After uptake of a [U-phenyl-14C]-DCP solution followed by a 48 h water chase, whole plants (L. minor, S. natans) or excised shoots were harvested and aqueous extracts were analysed by high performance liquid chromatography (HPLC). Metabolites were then isolated, submitted to enzymatic or chemical hydrolyses and characterised by electrospray ionisation-mass spectrometric analyses. Whereas DCP monoglucosides or more complex monoglucoside esters, either malonyl or acetyl, were found in most species, an unusual glucosyl-pentose conjugate was identified as the DCP major metabolite in L. minor and G. maxima. Our results showed for the first time the ability of five macrophytes to uptake and metabolise DCP and the characterisation of their metabolic pathways of DCP biotransformation.     

Portal absorption of 14C after ingestion of spiked milk with 14C-phenanthrene, 14C-benzo[a]pyrene or 14C-TCDD in growing pigs

Polycyclic aromatic hydrocarbons (PAHs) and dioxins are lipophilic organic pollutants occurring widely in the terrestrial environment. In order to study the PAHs and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) transfer in the food chain, pigs have been fed with milk mixed either with 14C-phenanthrene, with 14C-benzo[a]pyrene or with 14C-TCDD. The analysis of portal and arterial blood radioactivity showed that both PAHs and TCDD were absorbed with a maximum concentration at 4-6 h after milk ingestion. Then, the blood radioactivity decreased to reach background levels 24 h after milk ingestion. Furthermore, the portal and arterial blood radioactivities were higher for phenanthrene (even if the injected load was the lowest) than these of benzo[a]pyrene or these of TCDD, in agreement with their lipophilicity and water solubility difference. Main 14C absorption occurred during the 1-3 h time period after ingestion for 14C-phenanthrene and during the 3-6 h time period for 14C-benzo[a]pyrene and for 14C-TCDD. 14C portal absorption rate was high for 14C-phenanthrene (95%), it was close to 33% for 14C-benzo[a]pyrene and very low for 14C-TCDD (9%). These results indicate that the three studied molecules have a quite different behaviour during digestion and absorption. Phenanthrene is greatly absorbed and its absorption occurs via the blood system, whereas benzo[a]pyrene and TCDD are partly and weakly absorbed respectively. However these two molecules are mainly absorbed via the portal vein.