RESUMO
The microbial communities in mining impacted areas rely on a variety of mechanisms to survive in such extreme environments. In this work, a meta-taxonomic approach using 16S rRNA gene sequences was used to investigate the prokaryotic diversity of sediment samples from water bodies affected by acid mine drainage at the São Domingos mining area in the south of Portugal. Samples were collected in summer and winter from the most contaminated sites from where the water flows downstream to the freshwater of Chança's river reservoir. The prokaryotic diversity on water bodies' sediments allowed us to distinguish the highly contaminated sites (pH ≈ 2) from sites with intermediate levels of contamination (pH ≈ 3-6.5), and from sites without contamination (pH ≈ 7.5). The abundances of acidophiles of genera Acidiphilium, Acidibacter, Acidobacterium and Acidocella in the sediments were correlated with the level of acid mine drainage contamination. The two first genera were among the 30 most abundant prokaryotes in all contaminated samples, including one (SS2w), where the contamination was very diluted, thereby emphasizing the impact that such type of pollution can have in the microbial communities of sediments. In addition, the high abundances of archaeal taxa from class Thermoplasmata and of bacteria from family RCP1-48 in the sediments from the most contaminated site corroborate their importance in such ecosystems and a putative role in the generation of acid mine drainage.
Assuntos
Archaea/classificação , Bactérias/classificação , Sedimentos Geológicos/microbiologia , Mineração , Rios/microbiologia , Poluentes Químicos da Água , Ácidos , Portugal , RNA Ribossômico 16S/genéticaRESUMO
The prokaryotic communities of water bodies contaminated by acid mine drainage from the São Domingos mining area in southern Portugal were analyzed using a meta-taxonomics approach with 16S rRNA gene sequences. Samples were collected in two seasonal sampling campaigns (summer and winter of 2017) from the most contaminated sites from where the water flows downstream to the freshwater reservoir of the river Chança. The physicochemical data indicate a trend of decreasing acid mine drainage contamination downstream of the mining area to the Chança's reservoir. The most contaminated sites (pH = 2.3-3.1) are distinguished by prokaryotic diversity with high abundances of operational taxonomics units related to acidophiles (genera Metallibacterium, Acidibacter, Leptospirillum, Acidobacterium, Thiomonas, Acidicapsa, Acidocella, Acidiphilium; family Acidobacteriaceae, order CPla-3 termite group). Likewise, in the transition zone in the mouth of the contaminated water flow into the Chança´s reservoir (pH = 6.4), a specific prokaryotic flora exists with some acidophiles, but notably with a cyanobacteria bloom and a high abundance of the genus Sediminibacterium (family I; order Subsection III). Moreover, the strong correlation between the abundance of acidophiles and characteristic physiochemical parameters (metals, acidity, and sulfate) confirm their potential as biomarkers of acid mine drainage pollution.
Assuntos
Mineração , Ácidos , Portugal , RNA Ribossômico 16S , Rios , Poluentes Químicos da ÁguaRESUMO
Minerals are reported to dominate the electrical properties of honey and indicate its botanical and geographical origins. In this study, Electrochemical Impedance Spectroscopy (EIS) was used to assess the relation between mineral elements, electrical properties and botanical origin using three honey varieties - Citrus sp., Eucalyptus sp., and Erica sp. These varieties are identified through pollen analysis and market labelling. Flame atomic absorption and emission spectroscopies were used to quantify the concentrations of eight elements (potassium, sodium, calcium, magnesium, manganese, zinc, copper, and iron). Among all the mineral elements, potassium showed a consistent correlation with impedance. The potassium estimation in honey and standard solutions (calibration curve) had similar sensitivities of 153.43 nF/mM and 132.68 nF/mM, respectively. Additionally, the analysis revealed that potassium dominates the mineral composition, with the other species present in minimal quantities. The EIS technique showed high sensitivity to potassium and other ionisable species, making it possible to classify the botanical origin of these three honey types. The EIS technique proved to be both time and cost effective, yielding a classification rate higher than that achieved by analysing mineral composition.
Assuntos
Espectroscopia Dielétrica , Mel , Potássio , Mel/análise , Mel/classificação , Potássio/análise , Citrus/química , Citrus/classificaçãoRESUMO
We describe the construction of a BAC contig and identification of a minimal tiling path that encompass the dominant and monogenically inherited downy mildew resistance locus Pp523 of Brassica oleracea L. The selection of BAC clones for construction of the physical map was carried out by screening gridded BAC libraries with DNA overgo probes derived from both genetically mapped DNA markers flanking the locus of interest and BAC-end sequences that align to Arabidopsis thaliana sequences within the previously identified syntenic region. The selected BAC clones consistently mapped to three different genomic regions of B. oleracea. Although 83 BAC clones were accurately mapped within a â¼4.6 cM region surrounding the downy mildew resistance locus Pp523, a subset of 33 BAC clones mapped to another region on chromosome C8 that was â¼60 cM away from the resistance gene, and a subset of 63 BAC clones mapped to chromosome C5. These results reflect the triplication of the Brassica genomes since their divergence from a common ancestor shared with A. thaliana, and they are consonant with recent analyses of the C genome of Brassica napus. The assembly of a minimal tiling path constituted by 13 (BoT01) BAC clones that span the Pp523 locus sets the stage for map-based cloning of this resistance gene.