Hot or not? Discovery and characterization of a thermostable alditol oxidase from Acidothermus cellulolyticus 11B

We describe the discovery, isolation and characterization of a highly thermostable alditol oxidase from Acidothermus cellulolyticus 11B. This protein was identified by searching the genomes of known thermophiles for enzymes homologous to Streptomyces coelicolor A3(2) alditol oxidase (AldO). A gene (sharing 48% protein sequence identity to AldO) was identified, cloned and expressed in Escherichia coli. Following 6xHis tag purification, characterization revealed the protein to be a covalent flavoprotein of 47 kDa with a remarkably similar reactivity and substrate specificity to that of AldO. A steady-state kinetic analysis with a number of different polyol substrates revealed lower catalytic rates but slightly altered substrate specificity when compared to AldO. Thermostability measurements revealed that the novel AldO is a highly thermostable enzyme with an unfolding temperature of 84 °C and an activity half-life at 75 °C of 112 min, prompting the name HotAldO. Inspired by earlier studies, we attempted a straightforward, exploratory approach to improve the thermostability of AldO by replacing residues with high B-factors with corresponding residues from HotAldO. None of these mutations resulted in a more thermostable oxidase; a fact that was corroborated by in silico analysis

Separation of radium and actinium from historical Th-229 sources for production of radioisotopes for targeted alpha immunotherapy

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Thorium-229 quantified in historical Thorium-228 capsules

Thorium-229 is a valuable, but scarce, radionuclide for nuclear clock applications or targeted alpha therapy. While it is mostly produced by the decay of 233U, 229Th can also be produced by neutron irradiation of 226Ra. At SCK•CEN, capsules containing mainly 228Th (by-product of 226Ra irradiation) were characterized to quantify the present amounts of 229Th, 228Th, 227Ac, 226Ra with high resolution gamma spectroscopy, after a decay period of 40 years in which 228Th has decayed. High purity 229Th was quantified, and after recovery using radiochemical separation processes, it can be used to support ongoing research.status: publishe

Biodegradability assessment of advanced oxidation processes by means of respirometric measurements

Advance Oxidation Processes are considered a promising technology in degrading hazardous organic compounds into readily biodegradable intermediates. In this context, a proper measurement tool to determine the enhancement of the biodegradability of the wastewater is necessary. In this study, the opportunities of respirometric measurements to determine the possible enhancement of biodegradability of toxic wastewaters due to ozone treatment was investigated. Phenol was chosen to represent organic toxic wastewaters. Firstly, the inhibitory effect of phenol on the respirometric oxygen consumption of unacclimated biomass has been determined. Further, a solution with a phenol concentration of 250 mg/l has been treated with ozone at pH 3 and pH 9. Based on the performed COD, TOC, BOD, phenol concentration and respirometric measurements, it can be observed that in this case the ozone treatment at pH 9 a lower ozone dosage was necessary to enhance the biodegradability of the phenol solution. Furthermore, the SOUR graphs shows a significant difference between the ozone treatments and the ozone dosages. Hence, respirometric measurements can be used to determine the enhancement of the biodegradability due to ozone oxidation. Further investigation on this topic is necessary to determine the effect of acclimated biomass on the respirometric measurements.status: publishe

Bismuth-213 labeled nanobodies as a new treatment approach in Targeted Alpha Therapy

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213Bismuth-labeled nanobodies as a new treatment approach in Targeted Alpha Therapy

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Combining Bismuth-213 with Nanobodies: finding the perfect match for Targeted Alpha Therapy

This study investigates a novel targeted therapy which combines the α-emitter Bismuth-213 (213Bi) and HER2-targeting nanobodies (Nbs) to selectively kill HER2+ metastases in breast- and ovarian cancer. The use of nanobodies as vehicles in TAT is promising due to their excellent in vivo properties, high affinity and specificity, fast diffusion and clearance kinetics. Moreover, Nbs show good tumor penetration due to their small size. The aim of this study is to develop and evaluate the in vitro binding characteristics on HER+ SKOV-3 cells, the in vitro stability using radio-ITLC and HPLC and the in vivo biodistribution of 213Bi-DTPA HER2 targeting Nb.JRC.G.I.5-Advanced Nuclear Knowledg