Phosphatases in the soil environment

Enzymes play a key role in nutrient cycling in the soil environment. In this work, four phosphatases of the soil environment were investigated. A study of the effect of metal ions and metal ion concentrations on inorganic pyrophosphatase activity in three NH(,4)OAc-leached soils showed that seven of the metal ions tested promoted activity. The average efficiency of these metal ions in promoting pyrophosphatase in decreasing order was: Ca(\u272+) \u3e Mg(\u272+) \u3e Ba(\u272+) = Co(\u272+) \u3e Ni(\u272+) \u3e Zn(\u272+) \u3e Mn(\u272+). Sodium ions and K(\u27+) did not affect pyrophosphatase activity and Cu(\u272+) and Fe(\u272+) decreased this activity. Optimum pyrophosphatase activity occurred at a Mg(\u272+):PPi or Ca(\u272+):PPi ratio of 1:1. Protection of pyrophosphatase in the NH(,4)OAc-leached soils against heat inactivation by Mg(\u272+) and Ca(\u272+) was also observed;The rates of hydrolysis of seven organic and two inorganic phosphorus compounds added to soils and incubated under aerobic or waterlogged conditions showed that monomethyl phosphate, (beta)-glycerophosphate, and (alpha)-D-glucose-1-phosphate were hydrolyzed at similar rates in the three soils used. Disubstituted organic P compounds (e.g., diphenyl phosphate and bis-p-nitrophenyl phosphate) were hydrolyzed at slower rates than monosubstituted organic P compounds (e.g., phenyl phosphate and p-nitrophenyl phosphate). Of the two inorganic P compounds studied, ammonium tetrametaphosphimate did not hydrolyze in soils, and the rates of hydrolysis of phosphonitrilic hexamide were very small (6-13% hydrolyzed in 7 days) compared with those of the organic phosphates (30-100%). The rates of hydrolysis of the mono- and disubstituted organic P compounds were related to the levels of acid phosphatase and phosphodiesterase, respectively, in the three soils studied;Comparisons of pH optima and kinetic parameters (K(,m), V(,max), and E(,a)) for acid and alkaline phosphatases, phosphodiesterase, and pyrophosphatase among plant materials, manures, sewage sludges, and soils were made. A 120-day incubation experiment in which soils were treated with corn plant material, hog manure, or sewage sludge showed that these materials did not permanently increase acid phosphatase and pyrophosphatase activity of soils. Addition of sodium azide, however, decreased the activity of these enzymes significantly (P \u3c 0.05) after 120 days of incubation;Acid phosphatase and inorganic pyrophosphatase from sterile corn roots were inhibited by clay minerals. The inhibition of these enzymes by montmorillonite and illite followed partial noncompetitive kinetics while the inhibition by kaolinite followed partial competitive kinetics. The clay minerals did not release any inhibitory compounds, but their inhibition of acid phosphatase and pyrophosphatase seem due to the adsorption of these enzymes by the clay minerals. The adsorption of acid phosphatase and pyrophosphatase by clay minerals was considered ionic in nature

Mapping expert perspectives of the aviation sector

Aviation globally is characterised by significant change and consequently the future of the sector has always been difficult to predict. This study adopts a systemic approach based on findings from exploratory interviews with UK aviation academics to: determine the roles of stakeholders in the air transport system; report the current issues facing the sector; explore how these issues interact and impact on the stakeholders in the system; and speculate on the future implications. Six core stakeholders are identified: airlines, airports, consumers, manufacturers, governing institutions and interest groups. Nine core issues are reported, namely: local environment, climate change, peak oil, the state of the economy, social norms, demographics, disruptive events, national (or international) regulations and capacity. A matrix of interactions and their impacts and implications for managing the aviation system is then presented

Interaction of Nitrogen and Flue Gas Desulfurization Sulfur for Production of Corn

This poster was presented at the annual ASA/CSSA/SSSA meetings in Indianapolis, IN in Nov. 2006Nitrogen deficiency in soil often limits corn (Zea mays L.) growth, thus requiring fertilizer N inputs to achieve optimum yields. Nitrogen fertilizer is becoming more expensive and methods are needed to improve N use efficiency. Sulfur deficiency in several crops, including corn, has recently been observed in Ohio. However, little information is available related to the interaction of N and S fertilizers to effect the production of corn. Field experiments were conducted on a silt loam soil at Wooster, Ohio from 2002 to 2005 to test corn responses to the addition of N (seven rates from 0 to 233 kg ha-1) and S (two rates of 0 and 33 kg ha-1) from flue gas desulfurization (FGD) products. Corn grain yields, averaged over 4 years, were increased 7.0% when S was applied. This increase was statistically significant (P < 0.05). A statistically significant interaction effect of N by S was observed in 2004 and 2005 with the low N rates from 0 to 133 kg ha-1 responding better to S than the high N rates. The highest grain yields were reached at the 133 kg N ha-1 application rate with S addition. This suggests that S application can improve N use efficiency and decrease the amount of N required for optimum corn production. Reduced N fertilizer application rates can also help maintain good water quality. Nitrogen, P, K, Mg and S in corn grain were slightly increased by application of 33 kg ha-1 of S when N was applied at rates of 100 and 200 kg ha-1. These results indicate application of N fertilizer with S promoted uptake, by corn plants, of N and other major plant nutrients

Residue and Nutrient Management Under Reduced Tillage Systems

Presented at the ASA/CSSA/SSSA 2006 annual meetings in Indianapolis, Indian

Account Book, Lobster Fishermen, 1911-1917

Account book records lobster, cod, mackerel, haddock, herring and other fish catch and sales, as well as purchases of supplies for individual Lobster fishermen of Monhegan Island, including Maynard Brackett, C.B. Amerman, Dick Stanley and Scott Warren among others. Also includes some description of fishing grounds around the island, trawling, trap setting and hand lining. Middle of the book contains several pages of miscellaneous aphorisms

Functional Predictions of Microbial Communities in Soil as Affected by Long‐term Tillage Practices

Core Ideas Microbial function is important but difficult to assess in soil. An omics‐driven tool, PICRUSt, was used to characterize functions of soil microbial communities. No‐tillage compared with plow tillage was functionally enriched for most nutrient cycles. Many other functions integral to soil health can be explored by the PICRUSt omics approach. Soil microbial communities affect the soil\u27s biological, chemical, and physical properties, but there is still a knowledge gap regarding the long‐term impact of tillage practices on soil microbial dynamics. Additionally, the accurate identification of belowground microbial functions is a topic of active interest. In this study, microbial community profiles and functions in soil from a 50‐plus‐year‐old experiment in Ohio, representing one of the world\u27s longest running comparisons of a plow‐tillage system and a continuous no‐tillage system, were compared. The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) algorithm was used to predict associated functional traits from 16S rRNA gene sequences. Analysis of the sequences revealed a large number of unidentified operational taxonomic units (67%), which is consistent with expectations of the soil ecosystem. Next, we investigated gene and enzyme predictions for nitrogen, sulfur, and methane metabolism and hydrocarbon degradation in soil. Results indicated that no‐tillage was functionally enriched for most nutrient cycles. This study has allowed us to predict distinct functional profiles as a result of legacy land uses. It serves as an example of improved analysis of the functional differences in soil managed by long‐term tillage versus no‐till

Bacterial community dissimilarity in soils is driven by long-termland-use practices

Land‐use practices impact soil microbial functionality and biodiversity, with reports suggesting that anthropogenic activities potentially result in reduced microbial functions and loss of species. The objective of this study was to assess the effect of long‐term (\u3e50 yr) land use (natural forest and grassland, and agricultural land) on soil bacterial community structure. A high‐throughput sequencing‐by‐synthesis approach of the 16S rRNA gene was used to study bacterial community and predicted functional profiles of Alfisols, as affected by variables including land‐use (forest, grass, agricultural) and soil/crop management (rotation and tillage) in long‐term experimental plots in Hoytville, OH. The distribution of the abundant phyla was different across samples. No‐till soils showed higher diversity indices than the plow‐till (PT) soils. Ordinations across locations suggested that no‐till soils had distinctly different community structure compared with plow‐till soils, while crop rotation within the no‐till plot had highest number of taxa. Overall land use (forest, grass, agronomic treatment) and tillage (within agricultural soils) were found to be significant when evaluating bacterial community dissimilarity. Predictive functional profiles showed that the forest soil had greatest proportion of PICRUSt‐assignable gene functions followed by the no‐till and grassland soils whereas plow‐till soils had the lowest predicted gene abundances across all samples. The results provide a view of soil bacterial diversity and predictive functional capacity in long‐term land‐use and soil/crop management practices, with a potential to inform future experiments to increase our understanding of long‐term impacts of land use on microbial community structure and function

Identification and Characterization of NeuB3 from Campylobacter jejuni as a Pseudaminic Acid Synthase

Campylobacter jejuni and Campylobacter coli are the main causes of bacterial diarrhea worldwide, and Helicobacter pylori is known to cause duodenal ulcers. In all of these pathogenic organisms, the flagellin proteins are heavily glycosylated with a 2-keto-3-deoxy acid, pseudaminic acid (5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid). The presence of pseudaminic acid is required for the proper development of the flagella and is thereby necessary for motility in, and invasion of, the host. In this study we report the first characterization of NeuB3 from C. jejuni as a pseudaminic acid synthase; the enzyme directly responsible for the biosynthesis of pseudaminic acid. Pseudaminic acid synthase catalyzes the condensation of phosphoenolpyruvate (PEP) with the hexose, 2,4-diacetamido-2,4,6-trideoxy-L-altrose (6-deoxy-AltdiNAc), to form pseudaminic acid and phosphate. The enzymatic activity was monitored using 1H and 31P NMR spectroscopy, and the product was isolated and characterized. Kinetic analysis reveals that pseudaminic acid synthase requires the presence of a divalent metal ion for catalysis and that optimal catalysis occurs at pH 7.0. A coupled enzymatic assay gave the values for k(cat) of 0.65 +/- 0.01 s(-1), K(m)PEP of 6.5 +/- 0.4 microM, and K(m)6-deoxy-AltdiNAc of 9.5 +/- 0.7 microM. A mechanistic study on pseudaminic acid synthase, using [2-18O]PEP, shows that catalysis proceeds through a C-O bond cleavage mechanism similar to other PEP condensing synthases such as sialic acid synthase