Hydropeaking indicators for characterization of the Upper-Rhone River in Switzerland

River channelization and the construction of high-head storage schemes have been the basis of agricultural and socio-economic development in many alpine regions. One example is the Upper-Rhone River in Switzerland. The Upper-Rhone's morphology changed considerably between 1863 and 1960 as a result of two major channelizations and, from 1950 on, the construction of a large number of high-head storage hydropower schemes in the catchment. These modifications have brought large benefits to the local population, at the cost, however, of substantial disturbances in aquatic and terrestrial ecosystems in and along the river. A primary factor behind these disturbances is the alteration of the natural flow regime, namely hydropeaking due to the operation of the high-head storage hydropower plants. For sustainable river-restoration projects on regulated rivers, scientists and engineers now widely accept the necessity of integrated management of the river. Different aspects such as river morphology, sediment management, water quality, temperature, and the naturally variable flow regime should be considered simultaneously. Mitigation of non-natural, sub-daily flow fluctuations due to hydropeaking is a crucial step in restoring natural flow regimes, but is especially challenging due to the economic constraints such mitigation places upon hydropower plants. With the goal of addressing this challenge, this paper proposes three indicators to describe the flow regime of rivers in alpine catchments with and without high-head storage hydropower plants. The indicators quantify: (1) the seasonal distribution and transfer of water, (2) sub-daily flow fluctuations, and (3) the intensity and frequency of flow changes. Indicators are evaluated in a case study of the Upper-Rhone River for pre- and post-impact situations, and the benefit of a multipurpose project reducing hydropeaking on hydrologic conditions is quantified. Furthermore, the paper explores the possibility of using these indicators to link aquatic and terrestrial ecosystem well being to their hydrolog

Bt176 corn in poultry nutrition: physiological characteristics and fate of recombinant plant DNA in chickens

A genetically modified Bt176 corn hybrid, which contains an insecticidal protein against the European corn borer, and its conventional, nonmodified counterpart were evaluated in 4 separate trials to verify substantial equivalence in feeding value and animal performance. Thirty-six individually kept laying hens and 3 replicates of 94 broiler chickens each, assigned to 12 cages, were fed 2 different hen and broiler diets containing either 60% conventional or 60% Bt176 corn. The nutrient compositions of the 2 corn hybrids and the 2 corn diets revealed no major differences. Furthermore, metabolism and performance data revealed no significant differences between the birds that received the conventional, nonmodified corn, and those that received the modified corn diets. The detection of the genetic modification, by PCR, in feed obtained from insect-resistant Bt corn, in tissues and products from animals fed Bt corn is described. In all evaluated chicken tissues of muscle, liver, and spleen, the corn-chloroplast ivr gene fragment was amplified. It can be deduced from these findings and from other studies that the transfer of DNA fragments into the body is a normal process that takes place constantly. Nevertheless, no recombinant plant DNA fragments such as recombinant bla or cry1A(b) fragments could be found. Bt-gene specific constructs from the Bt corn were not detected in any of the poultry samples, neither in organs, meat, nor egg

Risk management and communication in informal dairy sector in Côte d’Ivoire: Options for sustainable livelihoods

Intervention in food and nutrition was the best investment for our collective future in terms of managing co-morbidity in population. This investment should combine agricultural system with health and education. Fermented dairy products (FDP) played an important role for prolonged shelf life, microbial safety and nutrition. FDP was proved to be contaminated in Kenya, Somalia, Mali and Côte d'Ivoire by foodborne pathogens including Staphylococcus aureus and Escherichia coli. Recently, it was showed that FDP was predominated by a novel Streptococcus infantarius subsp. infantarius (Sii) variant. Sii-produced bacteriocin and fermentation activity could contribute to the suppression of pathogens and possibly mitigate socioeconomic and health risks. However, Sii as member of Streptococcus bovis group was associated with human and animal infections. Therefore, a potential application of Sii as adapted African starter culture for enhanced food safety required a thorough safety assessment. In order to improve hygiene and quality as well as to increase production for school canteens, urban consumption and sustainable livelihoods, a cross-sectional study was conducted in Korhogo (Côte d’Ivoire) from May to August 2014. The objective was to assess local technologies and the dairy value chain in relation to Sii prevalence, followed by a participatory stakeholder workshop to validate findings and derive adapted interventions. The study showed that the dairy value chain contributed to livelihoods and household income. About 90% of milk produced (range: 12-44 liters/collector) were sold via collectors, generating 6-20 Euros per day shared among herder, collector and vendor. The remaining 10% were consumed within the household. However, dairy production was low and scattered due to informal practices resulting in poor quality product. Basic hygiene such as cleaning, washing, disinfecting was lacking. Milk quality depreciated with the local practices, access to clean water and energy. Future interventions identified by stakeholders comprised (i) awareness on local dairy hygiene and nutritional value for the population especially school children, (ii) stakeholders organization around cooperative to develop sustainable dairy model (public dairy with private management); (iii) promote healthy milk products for school canteen programme in Korhogo through adapted local dairy technology

Investigation of the sugar content in wood hydrolysates with iodometric titration and UPLC-ELSD

ArticleAutohydrolysis of birch wood is a mild pretreatment process, which gives a notable yield of sugars – monosaccharides and oligosaccharides – in the aqueous hydrolysate, while a solid lignocellulose fraction can be further processed into other valuable products within a biorefinery concept. In this work two analytical methods – iodometric titration and ultra-high performance liquid chromatography with evaporative light scattering detection (UPLC-ELSD) – have been optimized and compared for the determination of the sugar content in series of birch wood hydrolysates. The results of both methods were consistent and showed that the highest yield of sugars, mostly xylose, was obtained by hydrolysis at 180 °C after 75 min

Controls on Interspecies Electron Transport and Size Limitation of Anaerobically Methane-Oxidizing Microbial Consortia

About 382 Tg yr⁻¹ of methane rising through the seafloor is oxidized anaerobically (W. S. Reeburgh, Chem Rev 107:486–513, 2007, https://doi.org/10.1021/cr050362v), preventing it from reaching the atmosphere, where it acts as a strong greenhouse gas. Microbial consortia composed of anaerobic methanotrophic archaea and sulfate-reducing bacteria couple the oxidation of methane to the reduction of sulfate under anaerobic conditions via a syntrophic process. Recent experimental studies and modeling efforts indicate that direct interspecies electron transfer (DIET) is involved in this syntrophy. Here, we explore a fluorescent in situ hybridization-nanoscale secondary ion mass spectrometry data set of large, segregated anaerobic oxidation of methane (AOM) consortia that reveal a decline in metabolic activity away from the archaeal-bacterial interface and use a process-based model to identify the physiological controls on rates of AOM. Simulations reproducing the observational data reveal that ohmic resistance and activation loss are the two main factors causing the declining metabolic activity, where activation loss dominated at a distance of <8 μm. These voltage losses limit the maximum spatial distance between syntrophic partners with model simulations, indicating that sulfate-reducing bacterial cells can remain metabolically active up to ∼30 μm away from the archaeal-bacterial interface. Model simulations further predict that a hybrid metabolism that combines DIET with a small contribution of diffusive exchange of electron donors can offer energetic advantages for syntrophic consortia

The rise and fall of methanotrophy following a deepwater oil-well blowout

The blowout of the Macondo oil well in the Gulf of Mexico in April 2010 injected up to 500,000 tonnes of natural gas, mainly methane, into the deep sea1. Most of the methane released was thought to have been consumed by marine microbes between July and August 20102, 3. Here, we report spatially extensive measurements of methane concentrations and oxidation rates in the nine months following the spill. We show that although gas-rich deepwater plumes were a short-lived feature, water column concentrations of methane remained above background levels throughout the rest of the year. Rates of microbial methane oxidation peaked in the deepwater plumes in May and early June, coincident with a rapid rise in the abundance of known and new methane-oxidizing microbes. At this time, rates of methane oxidation reached up to 5,900 nmol l−1 d−1—the highest rates documented in the global pelagic ocean before the blowout4. Rates of methane oxidation fell to less than 50 nmol l−1 d−1 in late June, and continued to decline throughout the remainder of the year. We suggest the precipitous drop in methane consumption in late June, despite the persistence of methane in the water column, underscores the important role that physiological and environmental factors play in constraining the activity of methane-oxidizing bacteria in the Gulf of Mexico

Co-directional replication-transcription conflicts lead to replication restart

August 24, 2011Head-on encounters between the replication and transcription machineries on the lagging DNA strand can lead to replication fork arrest and genomic instability1, 2. To avoid head-on encounters, most genes, especially essential and highly transcribed genes, are encoded on the leading strand such that transcription and replication are co-directional. Virtually all bacteria have the highly expressed ribosomal RNA genes co-directional with replication3. In bacteria, co-directional encounters seem inevitable because the rate of replication is about 10–20-fold greater than the rate of transcription. However, these encounters are generally thought to be benign2, 4, 5, 6, 7, 8, 9. Biochemical analyses indicate that head-on encounters10 are more deleterious than co-directional encounters8 and that in both situations, replication resumes without the need for any auxiliary restart proteins, at least in vitro. Here we show that in vivo, co-directional transcription can disrupt replication, leading to the involvement of replication restart proteins. We found that highly transcribed rRNA genes are hotspots for co-directional conflicts between replication and transcription in rapidly growing Bacillus subtilis cells. We observed a transcription-dependent increase in association of the replicative helicase and replication restart proteins where head-on and co-directional conflicts occur. Our results indicate that there are co-directional conflicts between replication and transcription in vivo. Furthermore, in contrast to the findings in vitro, the replication restart machinery is involved in vivo in resolving potentially deleterious encounters due to head-on and co-directional conflicts. These conflicts probably occur in many organisms and at many chromosomal locations and help to explain the presence of important auxiliary proteins involved in replication restart and in helping to clear a path along the DNA for the replisome.Biotechnology and Biological Sciences Research Council (Great Britain) (Grant BB/E006450/1)Wellcome Trust (London, England) (Grant 091968/Z/10/Z)National Institutes of Health (U.S.) (Grant GM41934)National Institutes of Health (U.S.) (Postdoctoral Fellowship GM093408)Biotechnology and Biological Sciences Research Council (Great Britain) (Sabbatical Visit

The evolution of early diagenetic processes at the Mozambique margin during the last glacial-interglacial transition

The Mozambique continental margin experienced large variations in sedimentation rates, primarily due to re-routing of sediment deposition from the Zambezi River during the last glacial-Holocene transition. As changes in sediment accumulation and organic matter deposition impose a strong control on the formation of authigenic minerals in the sediment, the distribution of these minerals may reflect the regional paleoenvironmental and paleoclimatic evolution. Combining geochemical analyses of porewaters and sediments with a reactive transport modeling approach, we reconstruct the depositional history and its effect on pyrite formation and other biogeochemical transformations at a site on the Mozambique margin over the past 27 kyr. Fitting the model to match the observed geochemical patterns, most importantly authigenic pyrite, allowed for the reconstruction of past sulfate-methane transition zone depth, which migrated in response to changes in the sediment accumulation and organic matter deposition. Changes in sediment deposition quickly affected organoclastic sulfate reduction and associated pyrite formation, but the effect on anaerobic methane oxidation and subsequent pyrite formation occurred with a lag on the order of thousands of years. Model results reveal a transition from high diagenetic reaction rates representative of near-shore depositional environments during the late glacial maximum, to a setting typical of offshore sediments with low reaction rates at the present day. Notably, the remnants of methane and dissolved iron pools produced in the past still shape the diagenetic processes at and below the sulfate-methane transition zone today. Since deglacial shelf-flooding and corresponding changes in sediment deposition occurred along continental margins worldwide, our analysis highlights the important role of non-steady state diagenesis in continental margin sediments and its relevance for paleoceanographic interpretation of sediment cores experiencing strong variations in sediment input