Dynamic, ligand-dependent conformational change triggers reaction of ribose-1,5-bisphosphate isomerase from Thermococcus kodakarensis KOD1

Ribose-1,5-bisphosphate isomerase (R15Pi) is a novel enzyme recently identified as a member of an AMP metabolic pathway in archaea. The enzyme converts d-ribose 1,5-bisphosphate into ribulose 1,5-bisphosphate, providing the substrate for archaeal ribulose-1,5-bisphosphate carboxylase/oxygenases. We here report the crystal structures of R15Pi from Thermococcus kodakarensis KOD1 (Tk-R15Pi) with and without its substrate or product. Tk-R15Pi is a hexameric enzyme formed by the trimerization of dimer units. Biochemical analyses show that Tk-R15Pi only accepts the α-anomer of d-ribose 1,5-bisphosphate and that Cys(133) and Asp(202) residues are essential for ribulose 1,5-bisphosphate production. Comparison of the determined structures reveals that the unliganded and product-binding structures are in an open form, whereas the substrate-binding structure adopts a closed form, indicating domain movement upon substrate binding. The conformational change to the closed form optimizes active site configuration and also isolates the active site from the solvent, which may allow deprotonation of Cys(133) and protonation of Asp(202) to occur. The structural features of the substrate-binding form and biochemical evidence lead us to propose that the isomerase reaction proceeds via a cis-phosphoenolate intermediate.     

Process performance and bacterial community dynamics of partial‐nitritation biofilters subjected to different concentrations of cysteine amino acid

Partial‐nitritation processes are used for the biological treatment of high nitrogen‐low organic carbon effluents, such as anaerobic digestion reject water. The release of certain products generated during the anaerobic digestion process, such as amino acids, could potentially reduce the performance of these partial‐nitritation bioprocesses. To investigate this, four partial‐nitritation biofilters were subjected to continuous addition of 0, 150, 300, and 500 mg L^?1 cysteine amino acid in their influents. The addition of the amino acid had an impact over the performance of the partial‐nitritation process and the bacterial community dynamics of the systems analyzed. Ammonium oxidation efficiency decreased with the addition of the amino acid, and a net nitrogen elimination occurred in presence of cysteine through the operation period. Bacterial community dynamics showed a decrease of Nitrosomonas species and a proliferation of putative heterotrophs with nitrification capacity, such as Pseudomonas, or denitrification capacity, such as Denitrobacter or Alicycliphilus. The addition of cysteine irreversible affected the bioreactors, which could not achieve the performance obtained before the addition of the amino acid. A mathematical predictive equation of the process performance depending on cysteine concentration added and operational time under such concentration was developed. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1254–1263, 2016     

Cost-effectiveness of managing Natura 2000 sites: an exploratory study for Finland,Germany, the Netherlands and Poland

Natura 2000 sites are expected to assure the long-term survival of Europe’s most valuable and threatened species and habitats. It follows that successful management of the sites is of great importance. Next to goal attainment, cost-effectiveness is increasingly recognised as a key requirement for gaining social and political acceptance for costly conservation measures. We identify and qualitatively examine issues of cost-effectiveness related to the design and implementation of management measures in Natura 2000 sites in Finland, Germany, the Netherlands and Poland. Given the wide variety of management design and implementation options within the four countries, our study is purely of an exploratory nature. We derive recommendations for improving the cost-effectiveness of management in Natura 2000 sites and for future research. Examples of policy recommendations include guaranteeing the availability of funds for longer periods, and ensuring the appropriate allocation of funds between the different tasks of designing and implementing management plans. Further research should examine the cost-effectiveness of controversial suggestions such as, for example, more tailored payment schemes for conservation measures that result in higher ecological outputs but are costly to administer. Moreover, more research is needed to better understand how rules for administrations, as well as rules and governance structures for tasks within administrations, should be designed.     

Basic haematological values in the African buffalo (Syncerus caffer caffer) and in the red buffalo (Syncerus caffer nanus)

Basic haematological values in 13 African buffaloes (Syncerus caffer caffer), 11 cows and 2 bulls, and in 2 red buffaloes (Syncerus caffer nanus), 1 bull and 1 cow, are reported. In the African buffalo, the erythrocyte count--mean 9.76 X 10(12) 1(-1)--ranged from 6.72 to 12.42 X 10(12) 1(-1), the haematocrit values--mean 0.391--varied from 0.32 to 0.47 and the haemoglobin content--mean 148.17--was in the range from 122.1 to 172.5 g 1(-1). For the red buffalo only individual values are given. In the African buffaloes, the leukocyte counts--mean 7.39 X 10(9) 1(-1)--ranging from 5.1 to 12.4 X 10(9) 1(-1) were slightly increased compared with man. For the red buffalo only individual values are reported. These values are compared with data abstracted from the literature for related buffalo species. The age-dependent decrease of erythrocyte counts and the age-dependent rise of the eosinophile proportion in the differential count are discussed.     

Sex and season-related differences of basic haematological values in the mountain reedbuck (Reduncula fulvorufula).

1. Basic haematological values in the peripheral blood of four male and 13 female mountain reedbucks (Reduncula fulvorufula) have been repeatedly estimated. 2. Comparing these results for both sexes, we noted pronouncedly lower haematocrit values and haemoglobin contents in females (statistical significance less than or greater than 1%). In the white blood cells only an increased proportion of neutrophils in females was apparent. 3. We have been unable to find seasonal related differences in the red and white blood overall picture of the cells during the summer and winter seasons with the exception of raised red cell counts and increased proportion of monocytes in the winter. The presented findings are compared and discussed with those abstracted from the literature.