A keystone Methylobacterium strain in biofilm formation in drinking water

The structure of biofilms in drinking water systems is influenced by the interplay between biological and physical processes. Bacterial aggregates in bulk fluid are important in seeding biofilm formation on surfaces. In simple pure and co-cultures, certain bacteria, including Methylobacterium, are implicated in the formation of aggregates. However, it is unclear whether they help to form aggregates in complex mixed bacterial communities. Furthermore, different flow regimes could affect the formation and destination of aggregates. In this study, real drinking water mixed microbial communities were inoculated with the Methylobacterium strain DSM 18358. The propensity of Methylobacterium to promote aggregation was monitored under both stagnant and flow conditions. Under stagnant conditions, Methylobacterium enhanced bacterial aggregation even when it was inoculated in drinking water at 1% relative abundance. Laminar and turbulent flows were developed in a rotating annular reactor. Methylobacterium was found to promote a higher degree of aggregation in turbulent than laminar flow. Finally, fluorescence in situ hybridisation images revealed that Methylobacterium aggregates had distinct spatial structures under the different flow conditions. Overall, Methylobacterium was found to be a key strain in the formation of aggregates in bulk water and subsequently in the formation of biofilms on surfaces

Evaluation of a commercial fluorochromic system for the rapid detection and estimation of wine lactic acid bacteria by DEFT

A commercial fluorochromic system was evaluated for the rapid detection of lactic acid bacteria in fortified wines by the epifluorescent filter technique (DEFT). The viability test used, employing the fluorescence dyes SYTO 9 and propidium iodide, was able to detect and clearly differentiate viable from non-viable cells (killed with a 50% v/v ethanol solution). A good overall agreement (r= 0·92) was obtained between the DEFT count and the plate count in the range studied (5 × 102–4 × 109 cells ml−1). Wine components which might otherwise interfere with the method could be removed by including simple wash steps in the protocol. This measure proved critical to the success of the procedure. For practical purposes, the rapid method studied seems to be a good alternative to the traditional cultural methods as part of quality control programmes in wine making. It may also be useful when studying the efficacy of certain treatments in the elimination of wine bacterial contaminants

Metagenomic sequencing unravels gene fragments with phylogenetic signatures of O2-tolerant NiFe membrane-bound hydrogenases in lacustrine sediment

Many promising hydrogen technologies utilising hydrogenase enzymes have been slowed by the fact that most hydrogenases are extremely sensitive to O2. Within the group 1 membrane-bound NiFe hydrogenase, naturally occurring tolerant enzymes do exist, and O2 tolerance has been largely attributed to changes in iron–sulphur clusters coordinated by different numbers of cysteine residues in the enzyme’s small subunit. Indeed, previous work has provided a robust phylogenetic signature of O2 tolerance [1], which when combined with new sequencing technologies makes bio prospecting in nature a far more viable endeavour. However, making sense of such a vast diversity is still challenging and could be simplified if known species with O2-tolerant enzymes were annotated with information on metabolism and natural environments. Here, we utilised a bioinformatics approach to compare O2-tolerant and sensitive membrane-bound NiFe hydrogenases from 177 bacterial species with fully sequenced genomes for differences in their taxonomy, O2 requirements, and natural environment. Following this, we interrogated a metagenome from lacustrine surface sediment for novel hydrogenases via high-throughput shotgun DNA sequencing using the Illumina™ MiSeq platform. We found 44 new NiFe group 1 membrane-bound hydrogenase sequence fragments, five of which segregated with the tolerant group on the phylogenetic tree of the enzyme’s small subunit, and four with the large subunit, indicating de novo O2-tolerant protein sequences that could help engineer more efficient hydrogenases

How many green jobs are there in electricity generation? A replicable quantification method for developing countries under data constraints

Assessing the scale of green jobs and the socioeconomic effects of the energy transition is relevant and timely, while clear, comparable methodologies are still scarce. The discussion around just transitions, and the extent to which renewable energy creates more positive socioeconomic impacts than fossil fuels, increasingly attracts policymakers' and researchers' attention. However, data constraints, particularly in developing economies, expose a relevant gap in providing quantitative evidence for such discussions. This is especially relevant in countries with outstanding potential for renewable deployments, such as the case of Brazil. Existing data usually is considerably aggregated into activities irrespectively of technology or Greenhouse gas emission profile, and general international frameworks for such quantification may prove inadequate. In this paper, we propose a replicable data triangulation approach to disaggregate electricity jobs and wages into renewable and non-renewable electricity generation sources applied to the case of Brazil, using national accounts data, energy generation statistics and electricity-source specific employment coefficients from where data is available. One can use the resulting dataset either purely as the current scale of renewable and non-renewable electricity jobs and income or as the database for further modelling projections, particularly macroeconomic, multisectoral models, namely input-output and computable general equilibrium models

A influência de variáveis ambientais no crescimento de espécies/procedências de Eucalyptus spp. nos estados de Minas Gerais e Espírito Santo.

Foram analisados onze experimentos de introdução de espécies e procedências potenciais de Eucalyptus instalados em várias localidades dos estados de Minas Gerais e Espírito Santo. O estudo da influência de variáveis ambientais dos locais de introdução no crescimento em altura dessas espécies, aos três anos e meio de idade, permitiu concluir que a altitude do local do experimento foi a variável que mais influenciou o crescimento em altura de Eucalyptus camaldulensis, E. dunnii, E. grandis, E. pellita e E. tereticornis; o déficit hídrico isoladamente influenciou significativamente apenas o crescimento em altura de E. urophylla; a temperatura média e o total anual de precipitações não influenciaram isoladamente o crescimento em altura das oito espécies estudadas, e que é possível prever o comportamento das espécies e procedências em relação ao crescimento em altura, conhecendo-se a altitude, déficit hídrico e total anual médio de precipitações do local de introdução

Ethanol-induced changes in the fatty acid composition of Lactobaci//us hilgardii, its effects on plasma membrane fluidity and relationship with ethanol tolerance

The effect of environmental ethanol concentration on the fatty acid composition of strains of Lactobacillus hilgardii, differing in their tolerance to ethanol, was determined. A marked increase in the proportion of lactobacillic acid (a cyclopropane fatty acid) and a decrease in oleic and vaccenic acids with increasing ethanol concentration was observed. The amount of lactobacillic acid determined at standard conditions (25°C, 0% ethanol) was found to be proportional to the ethanol tolerance of the strains studied. The effect of this alcohol on plasma membrane fluidity was studied by differential scanning calorimetry. The adaptive response to growth in the presence of high concentrations of ethanol produced membranes which, within the limits of ethanol tolerance, maintained the fluidity and integrity in an environment which tends to increase membrane rigidity. When pre-adapted cells are analysed in the absence of environmental ethanol there is a measurabie increase in fluidity. It is proposed that this phenomenon may be correlated with the increase in the proportion of lactobacillic acid. The existence of a relationship between membrane fluidity and ethanol tolerance is discussed

Performance of a Low Noise Front-end ASIC for Si/CdTe Detectors in Compton Gamma-ray Telescope

Compton telescopes based on semiconductor technologies are being developed to explore the gamma-ray universe in an energy band 0.1--20 MeV, which is not well covered by the present or near-future gamma-ray telescopes. The key feature of such Compton telescopes is the high energy resolution that is crucial for high angular resolution and high background rejection capability. The energy resolution around 1 keV is required to approach physical limit of the angular resolution due to Doppler broadening. We have developed a low noise front-end ASIC (Application-Specific Integrated Circuit), VA32TA, to realize this goal for the readout of Double-sided Silicon Strip Detector (DSSD) and Cadmium Telluride (CdTe) pixel detector which are essential elements of the semiconductor Compton telescope. We report on the design and test results of the VA32TA. We have reached an energy resolution of 1.3 keV (FWHM) for 60 keV and 122 keV at 0 degree C with a DSSD and 1.7 keV (FWHM) with a CdTe detector.Comment: 6 pages, 7 figures, IEEE style file, to appear in IEEE Trans. Nucl. Sc