Synthesis of heparosan oligosaccharides by Pasteurella multocida PmHS2 single-action transferases

Pasteurella multocida heparosan synthase PmHS2 is a dual action glycosyltransferase that catalyzes the polymerization of heparosan polymers in a non-processive manner. The two PmHS2 single-action transferases, obtained previously by site-directed mutagenesis, have been immobilized on Ni(II)-nitrilotriacetic acid agarose during the purification step. A detailed study of the polymerization process in the presence of non-equal amounts of PmHS2 single-action transferases revealed that the glucuronyl transferase (PmHS2-GlcUA+) is the limiting catalyst in the polymerization process. Using experimental design, it was determined that the N-acetylglucosaminyl transferase (PmHS2-GlcNAc+) plays an important role in the control of heparosan chain elongation depending on the number of heparosan chains and the UDP-sugar concentrations present in the reaction mixture. Furthermore, for the first time, the synthesis of heparosan oligosaccharides alternately using PmHS2-GlcUA+ and PmHS2-GlcNAc+ is reported. It was shown that the synthesis of heparosan oligosaccharides by PmHS2 single-action transferases do not require the presence of template molecules in the reaction mixture

Human-Centered Computer Vision

Contains fulltext : 241512.pdf (Publisher’s version ) (Open Access)Symposium on The Art and Science of Pattern Recognitio

Contextual Richness and Word Learning: Context Enhances Comprehension but Retrieval Enhances Retention

Learning new vocabulary from context typically requires multiple encounters during which word meaning can be retrieved from memory or inferred from context. We compared the effect of memory retrieval and context inferences on short‐ and long‐term retention in three experiments. Participants studied novel words and then practiced the words either in an uninformative context that required the retrieval of word meaning from memory (“I need the funguo”) or in an informative context from which word meaning could be inferred (“I want to unlock the door: I need the funguo”). The informative context facilitated word comprehension during practice. However, later recall of word form and meaning and word recognition in a new context were better after successful retrieval practice and retrieval practice with feedback than after context‐inference practice. These findings suggest benefits of retrieval during contextualized vocabulary learning whereby the uninformative context enhanced word retention by triggering memory retrieval

Somatic CTG•CAG repeat instability in a mouse model for myotonic dystrophy type 1 is associated with changes in cell nuclearity and DNA ploidy

Contains fulltext : 52050.pdf ( ) (Open Access)BACKGROUND: Trinucleotide instability is a hallmark of degenerative neurological diseases like Huntington's disease, some forms of spinocerebellar ataxia and myotonic dystrophy type 1 (DM1). To investigate the effect of cell type and cell state on the behavior of the DM1 CTG*CAG repeat, we studied a knock-in mouse model for DM1 at different time points during ageing and followed how repeat fate in cells from liver and pancreas is associated with polyploidization and changes in nuclearity after the onset of terminal differentiation. RESULTS: After separation of liver hepatocytes and pancreatic acinar cells in pools with 2n, 4n or 8n DNA, we analyzed CTG*CAG repeat length variation by resolving PCR products on an automated PAGE system. We observed that somatic CTG*CAG repeat expansion in our DM1 mouse model occurred almost uniquely in the fraction of cells with high cell nuclearity and DNA ploidy and aggravated with aging. CONCLUSION: Our findings suggest that post-replicative and terminal-differentiation events, coupled to changes in cellular DNA content, form a preconditional state that influences the control of DNA repair or recombination events involved in trinucleotide expansion in liver hepatocytes and pancreatic acinar cells

Septicaemia with Dysgonic Fermenter -2 (DF-2) bacterium in a compromised host

Contains fulltext : 4451.pdf (publisher's version ) (Open Access

Petroleum Engineering Techniques for HLW Disposal

This paper describes why petroleum engineering techniques are of importance and can be used for underground disposal of HLW (high-level radioactive waste). It is focused on rock salt as a geological host medium in combination with disposal of the HLW canisters in boreholes drilled from the surface. Both permanent disposal and disposal with the option to retrieve the waste are considered. The paper starts with a description of the disposal procedure. Next disposal in deep boreholes is treated. Then the possible use of deviated boreholes and of multiple boreholes is discussed. Also waste isolation aspects and the implications of the HLW heat generation are treated. It appears that the use of deep boreholes can be beneficial, and also that--to a certain extent--borehole deviation offers possibilities. The benefits of using multiple boreholes are questionable for permanent disposal, while this technique cannot be applied for retrievable disposal. For the use of casing material, the additional temperature rise due to the HLW heat generation must be taken into account