Expression of Carbohydrates Biosynthetic Genes in Developing Soybean Seeds

An essential part of livestock diets is soybean meal, which is a major source of protein, but which also consists of antinutritional carbohydrates. Antinutritional carbohydrates such as raffinose and stachyose lead to irritation to the gut for monogastric livestock as well as unhealthy weight gain. A major objective of soybean genetics is to reduce these antinutritional carbohydrates within the seed and increase the levels of good carbohydrates. This will lead to healthier livestock and better meat quality. To select genes potentially responsible for variation in carbohydrate levels in seeds, the expression of genes encoding several biosynthetic enzymes was measured during soybean seed development. Genes were selected on the basis of working knowledge of the raffinose/sucrose biosynthetic pathways. Soybean plants were grown in controlled conditions within the growth chamber and seeds were collected at five defined intervals during seed development. RNA was extracted from the seeds and expression of genes of interest were measured using quantitative RT-PCR. Expression of these genes were compared between wild type soybean and the lab’s carbohydrate composition mutants and from lines from the soybean genetic stock center that differ from commodity soybean by having higher levels of sucrose

Mine waste characterization, management and remediation

Mining is a vital part of the Global economy, but the extraction of metals, metalloids, and other mineral products generates vast quantities of liquid and solid waste. Currently the volume is estimated at several thousand million tons per annum, but is increasing exponentially as demand and exploitation of lower-grade deposits increases. The high concentrations of potentially toxic elements in these wastes can pose risks to ecosystems and humans, but these risks can be mitigated by implementing appropriate management or remediation schemes. Although there are a large number of such schemes available, there is still a need to research the processes, products, and effectiveness of implementation, as well as the nature of the mine wastes themselves. This Special Issue is aimed at bringing together studies in the areas of mine waste characterization, management, and remediation, to review the current state of knowledge and to develop improvements in current schemes. Fourteen manuscripts are published for this Special Issue, and these are summarized below.[...

The Lake Bond deposit: superimposed volcanogenic and synorogenic base and precious metal mineralization in the Robert's Arm Group, central Newfoundland

The Lake Bond deposit is hosted by Lower Ordovician volcanic rocks of the Robert's Arm Group. Detailed penological studies indicate that there are two generations of superimposed alteration and sulphide deposition. The first generation mineralization is pre-kinematic, and is characterized by pyrite and Cu-Zn sulphides associated with pervasive chloritization and locally intense quartz-sericite alteration. The second generation mineralization occurs in syn- to post-kinematic veins, and comprises locally auriferous Cu-Zn-Pb sulphides in a dominantly Ca-Mg-Fe silicate gangue. First generation mineralization resulted in 5x to 100x enrichments in Cu, Zn, Pb, Au, As, Sb, Cd and Ba, with respect to the probable source basalts. Second generation veins, in contrast, carry 100x to 1000x enrichments in most of these metals (except Sb and Ba), substantial enrichments in Fe and Mn, ?10x enrichment in Ag, and a marked increase in the enrichment of Pb, Au, As and Ag relative to Cu and Zn compared to the first generation mineralization. Sphalerites in second generation veins are enriched in Cd, Mn and Fe relative to first generation sphalerites, parallelling enrichments in the whole rocks. The Ca-Mg-Fe vein silicate assemblage suggests fluid temperatures greater than 200°C and possibly greater than 300°C; abundant calcite in the veins implies that CO2 may have influenced mineralization. Fluid inclusions in second generation sphalerite yield average homogenization temperatures of about 306°C. The timing of deformation and second generation mineralization in the Lake Bond deposit is constrained to the early Silurian by cross-cutting relationships with dated post-tectonic plutons. Comparisons with other deposits in the Robert's Arm Group and deposits elsewhere in central Newfoundland suggest a two-stage metallogenic model comprising: (1) an early volcanogenic event coeval with the Lower Ordovician host rocks; and (2) early Silurian hydrothermal activity related to shearing and movement on major faults. The latter is tentatively correlated with a widespread lode gold mineralizing event in central Newfoundland. The second generation auriferous mineralization apparently preferentially overprinted early sulphide zones at Lake Bond suggesting an exploration potential for auriferous zones within low-grade volcanogenic sulphide stockworks in the Buchans-Robert's Arm Belt. RÉSUMÉ Le gite de Lake Bond est encaissé dans les volcanites du Groupe de Robert's Arm (Ordovicien inférieur). Des études pétrologiques détaillées meltent en évidence deux générations au sein desquelles une altération se superpose au dépôt des sulfures. La minéralisation de première génération est précinématique et se caractérise par de la pyrite et des sulfures de Cu-Zn associés à une chloritisation penétrante ainsi qu'à une altération à quartz et sericite localemenl intense. La minéralisation de seconde génération se développe dans des veines syn- à postcinemauques et comprend des sulfures à Cu-Zn-Pb localement auriferes à l'intérieur d'une gangue silicatée à dominante Ca-Fe-Mg. La minéralisation de première génération engendra un enrichissement de 5 à 100 fois en Cu, Zn, Pb, Au, As, Sb, Cd et Ba par rapport aux basaltes dont elle est probablement issue. En revanche, les veines de seconde génération présentent un enrichissement de 100 à 1000 fois pour la plupart de ces métaux (hormis Sb et Ba), un enrichissement substantiel en Fe et Mn, un enrichissement supérieur à 10 fois en Ag, ainsi qu'un accroissement marque de l'enrichissement en Pb, Au, As et Ag au regard de Cu et Zn par rapport à la minéralisation de première génération. En comparaison des blendes de première génération, les blendes localised dans les veines de second génération sont enrichies en Cd, Mn, Fe d 'une façon comparable à l’enrichissement de laroche to tale. L'assemblage silicaté à Ca-Fe-Mg des veines suggére une température des fluides supérieure à 200°C et peut-être dépassant les 300°C; l'abondance de calcite dans ces veines suggére une influence du CO2 sur la minéralisation. Les inclusions fluides dans la blende de seconde génération livrent des températures moyennes d'homogénéisation autour de 306°C. Le recoupement par des plutons post-cinématiques dont l'âge est connu permet de cantonner la déformation et la minéralisation de seconde génération dans le gite de Lake Bond au début du Silurien. Une comparaison avec les autres gites présents dans le Groupe de Robert's Arm ainsi qu'avec des gites situés en d'autres points du centre de Terre-Neuve suggére un modèle métallogénique en deux étapes qui sont: (1) un épisode volcanogène précoce contemporain des roches éncaissantes ordoviciermes inférieures et (2) un hydrothermalisme eosilurien en liaison avec un cisaillement et un déplacement le long de failles majeures. On conele provisoirement cet hydrothermalisme avec un épisode repandu de minéralisation filonienne en or dans le centre de Terre-Neuve. Il semble qu'à Lake Bond, la minéralisation aurifere de seconde génération se soit supérposée aux zones de sulfures précoces, ce qui suggére un potentiel d'exploration pour les zones auriferes au sein des stockwerks de sulfures volcanogènes à faible teneur dans la ceinture de Buchans-Robert's Arm. [Traduit par le journal

Microbial oxidation of arsenite in a subarctic environment: diversity of arsenite oxidase genes and identification of a psychrotolerant arsenite oxidiser

Background: Arsenic is toxic to most living cells. The two soluble inorganic forms of arsenic are arsenite (+3) and arsenate (+5), with arsenite the more toxic. Prokaryotic metabolism of arsenic has been reported in both thermal and moderate environments and has been shown to be involved in the redox cycling of arsenic. No arsenic metabolism (either dissimilatory arsenate reduction or arsenite oxidation) has ever been reported in cold environments (i.e. < 10°C). Results: Our study site is located 512 kilometres south of the Arctic Circle in the Northwest Territories, Canada in an inactive gold mine which contains mine waste water in excess of 50 mM arsenic. Several thousand tonnes of arsenic trioxide dust are stored in underground chambers and microbial biofilms grow on the chamber walls below seepage points rich in arsenite-containing solutions. We compared the arsenite oxidisers in two subsamples (which differed in arsenite concentration) collected from one biofilm. 'Species' (sequence) richness did not differ between subsamples, but the relative importance of the three identifiable clades did. An arsenite-oxidising bacterium (designated GM1) was isolated, and was shown to oxidise arsenite in the early exponential growth phase and to grow at a broad range of temperatures (4-25°C). Its arsenite oxidase was constitutively expressed and functioned over a broad temperature range. Conclusions: The diversity of arsenite oxidisers does not significantly differ from two subsamples of a microbial biofilm that vary in arsenite concentrations. GM1 is the first psychrotolerant arsenite oxidiser to be isolated with the ability to grow below 10°C. This ability to grow at low temperatures could be harnessed for arsenic bioremediation in moderate to cold climates

Enhancing As(V) adsorption and passivation using biologically formed nano-sized FeS coatings on limestone: implications for acid mine drainage treatment and neutralization

The iron-reducing bacterium Acidiphilium cryputum JF-5 and a sulfate reducing bacterium (SRB) collected and purified from the mine drainage of a copper mine in the northwest of Sichuan Province, China, were used to biologically synthesize nano-sized FeS-coated limestone to remove As(V) from solution. The adsorption efficiency of As(V) is improved from 6.64 μg/g with limestone alone to 187 μg/g with the FeS coated limestone in both batch and column experiments. The hydraulic conductivity of the columns are also improved by the presence of the nano-sized FeS coatings, but the solution neutralization performance of the limestone can be reduced by passivation by gypsum and Fe(III) precipitates. Calculations for FeS-coated limestone dissolution experiments show that the process can be described as nCa.sol=At1/2-nCa,gyp. The results suggest that FeS-coated limestone may be an effective medium for remediating As(V)-bearing solutions such as acid mine drainage in systems such as Permeable Reactive Barriers

An investigation of vocational progression pathways for young people and adults in building crafts and hospitality CoVEs: a London case study

This report was commissioned by the Learning and Skills Development Agency’s (LSDA’s) strategic programme of research and development, funded by the Learning and Skills Council (LSC). Project aims and objectives The principal aim of this project is to explore how vocational pathways have been developed and enhanced in two occupational areas – building crafts and hospitality – among 14–19 year olds and employed adults in London

In situ arsenic oxidation and sorption by a Fe-Mn binary oxide waste in soil

The ability of a Fe-Mn binary oxide waste to adsorb arsenic (As) in a historically contaminated soil was investigated. Initial laboratory sorption experiments indicated that arsenite [As(III)] was oxidized to arsenate [As(V)] by the Mn oxide component, with concurrent As(V) sorption to the Fe oxide. The binary oxide waste had As(III) and As(V) adsorption capacities of 70 mg g−1 and 32 mg g−1 respectively. X-ray Absorption Near-Edge Structure and Extended X-ray Absorption Fine Structure at the As K-edge confirmed that all binary oxide waste surface complexes were As(V) sorbed by mononuclear bidentate corner-sharing, with 2 Fe at ∼3.27 Ǻ. The ability of the waste to perform this coupled oxidation-sorption reaction in real soils was investigated with a 10% by weight addition of the waste to an industrially As contaminated soil. Electron probe microanalysis showed As accumulation onto the Fe oxide component of the binary oxide waste, which had no As innately. The bioaccessibility of As was also significantly reduced by 7.80% (p < 0.01) with binary oxide waste addition. The results indicate that Fe-Mn binary oxide wastes could provide a potential in situ remediation strategy for As and Pb immobilization in contaminated soils

Computer simulations of the interactions of the (012) and (001) surfaces of jarosite with Al, Cd, Cu2+ and Zn

Jarosite is an important mineral on Earth, and possibly on Mars, where it controls the mobility of iron, sulfate and potentially toxic metals. Atomistic simulations have been used to study the incorporation of Al3+, and the M2+ impurities Cd, Cu and Zn, in the (0 1 2) and (0 0 1) surfaces of jarosite. The calculations show that the incorporation of Al on an Fe site is favorable on all surfaces in which terminal Fe ions are exposed, and especially on the (0 0 1) [Fe3(OH)3]6+ surface. Incorporation of Cd, Cu or Zn on a K site balanced by a K vacancy is predicted to stabilize the surfaces, but calculated endothermic solution energies and the high degree of distortion of the surfaces following incorporation suggest that these substitutions will be limited. The calculations also suggest that incorporation of Cd, Cu and Zn on an Fe site balanced by an OH vacancy, or by coupled substitution on both K and Fe sites, is unfavorable, although this might be compensated for by growth of a new layer of jarosite or goethite, as predicted for bulk jarosite. The results of the simulations show that surface structure will exert an influence on uptake of impurities in the order Cu > Cd > Zn, with the most favorable surfaces for incorporation being (0 1 2) [KFe(OH)4]0 and (0 0 1) [Fe3(OH)3]6+

River sediment geochemistry and provenance following the Mount Polley mine tailings spill, Canada:The role of hydraulic sorting and sediment dilution processes in contaminant dispersal and remediation

The failure of the Mount Polley tailings storage facility (TSF) in August 2014 was one of the largest magnitude failures on record, and released approximately 25 Mm3 of material, including c. 7.3 Mm3 of tailings into Hazeltine Creek, part of the Quesnel River watershed. This study evaluates the impact of the spill on the geochemistry of river channel and floodplain sediments and utilizes Pb isotope ratios and a multi-variate mixing model to establish sediment provenance. In comparison to sediment quality guidelines and background concentrations, Cu and V were found to be most elevated. Copper in river channel sediments ranged from 88-800 mg kg-1, with concentrations in sand-rich and clay/silt-rich sediments being statistically significantly different. Concentrations in river channel were believed to be influenced by hydraulic sorting during the rising and falling limbs of the flood wave caused by the tailings spill. Results highlight the importance of erosive processes, instigated by the failure, in incorporating soils and sediments into the sediment load transported and deposited within Hazeltine Creek. In this instance, these processes diluted tailings with relatively clean material that reduced metal concentrations away from the TSF failure. This does however, highlight environmental risks in similar catchments downstream of TSFs that contain metal-rich sediment within river channels and floodplain that have been contaminated by historical mining

Origin and Fate of Vanadium in the Hazeltine Creek Catchment following the 2014 Mount Polley Mine Tailings Spill in British Columbia, Canada

This is the final version. Available on open access from American Chemical Society via the DOI in this recordResults are presented from the analysis of aqueous and solid-phase V speciation within samples collected from the Hazeltine Creek catchment affected by the August 2014 Mount Polley mine tailings dam failure, Canada. Electron microprobe and XANES analysis found that V is present as V3+ substituted into magnetite, and V3+ and V4+ substituted into titanite, both of which occur in the spilled Mount Polley tailings. Secondary Fe oxyhydroxides forming in inflow waters and on creek beds have V K-edge XANES spectra exhibiting E½ positions and pre-edge features consistent with the presence of V5+ species, suggesting sorption of this species on these secondary phases. PHREEQC modelling suggests that the stream waters mostly contain V5+, and the inflow and pore waters contain a mixture of V3+ and V5+. These data, and stream, inflow and pore water chemical data, suggest that dissolution of V(III)-bearing magnetite, V(III,IV)-bearing titanite, V(V)-bearing Fe(-Al-Si-Mn) oxhydroxides, V-bearing Al(OH)3 and/or -clay minerals may have occurred. In the circumneutral pH environment of Hazeltine Creek elevated V concentrations are likely naturally attenuated by formation of V(V)-bearing secondary Fe oxyhydroxide, Al(OH)3 or clay mineral colloids, suggesting that the V is not bioavailable. A conceptual model is presented describing the origin and fate of V in Hazeltine Creek that is applicable to other river systems.Natural Environment Research Council (NERC