Metabolism of Poly(3-hydroxyalkanoates) (PHAs) by Pseudomonas oleovorans. Identification and Sequences of Genes and Function of the Encoded Proteins in the Synthesis and Degradation of PHA

Pseudomonas oleovorans accumulates poly(3-hydroxyalkanoates) (PHAs) after growth on medium chain length hydrocarbons. Large amounts of this polyester are synthesized when cells are grown under nitrogen-limiting conditions. When nitrogen is resupplied in the medium, the accumulated PHA is degraded. In this paper, we describe mutants which are defective in the synthesis or in the degradation of PHA. These mutants were used to select DNA fragments which encode PHA polymerases and a PHA depolymerase. A 25-kilobase (kb) DNA fragment was isolated from P. oleovorans that complements a Pseudomonas putida mutant unable to accumulate PHA. Subcloning resulted in the assignment of a 6.4-kb EcoRI fragment as the pha locus, containing genetic information of PHA synthesis. Mutants in the PHA degradation pathway were also complemented by this fragment, indicating that genes encoding PHA biosynthetic and degradative enzymes are clustered. Analysis of the DNA sequence of the 6.4-kb fragment revealed the presence of two open reading frames encoding PHA polymerases based on homology to the poly(3-hydroxybutyrate) polymerase from Alcaligenes eutrophus. A third open reading frame complemented the PHA degradation mutation and is likely to encode a PHA depolymerase. The presence of two PHA polymerases is due to a 2098-base pair DNA duplication. The PHA polymerases are 53% identical and show 35-40% identity to the poly(3-hydroxybutyrate) polymerase. No clear difference in specificity was found for the PHA polymerases. However, with the pha locus cloned on a multicopy vector, a polymer was accumulated that contains a significantly higher amount of substrate-derived monomers. An increase in the rate of polyester synthesis versus oxidation of the monomers in the beta-oxidation explains these findings

A novel series of positive modulators of the AMPA receptor : discovery and structure based hit-to-lead studies

Starting from an HTS derived hit 1, application of biostructural data facilitated rapid optimization to lead 22, a novel AMPA receptor modulator. This is the first demonstration of how structure based drug design can be exploited in an optimization program for a glutamate receptor

Modulation of Conductance and Ion Selectivity of OmpF Porin by La3+ Ions

Background: Auditing is an important tool to identify practice variation and 'best practices'. The Dutch Pancreatic Cancer Audit is mandatory in all 18 Dutch centers for pancreatic surgery. Methods: Performance indicators and case-mix factors were identified by a PubMed search for randomized controlled trials (RCT's) and large series in pancreatic surgery. In addition, data dictionaries of two national audits, three institutional databases, and the Dutch national cancer registry were evaluated. Morbidity, mortality, and length of stay were analyzed of all pancreatic resections registered during the first two audit years. Case ascertainment was cross-checked with the Dutch healthcare inspectorate and key-variables validated in all centers. Results: Sixteen RCT's and three large series were found. Sixteen indicators and 20 case-mix factors were included in the audit. During 2014-2015, 1785 pancreatic resections were registered including 1345 pancreatoduodenectomies. Overall in-hospital mortality was 3.6%. Following pancreatoduodenectomy, mortality was 4.1%, Clavien-Dindo grade >= III morbidity was 29.9%, median (IQR) length of stay 12 (9-18) days, and readmission rate 16.0%. In total 97.2% of >40,000 variables validated were consistent with the medical charts. Conclusions: The Dutch Pancreatic Cancer Audit, with high quality data, reports good outcomes of pancreatic surgery on a national level