Activity, stability and 3-D structure of the Cu(II) form of a chitin-active lytic polysaccharide monooxygenase from Bacillus amyloliquefaciens

The enzymatic deconstruction of recalcitrant polysaccharide biomass is central to the conversion of these substrates for societal benefit, such as in biofuels. Traditional models for enzyme-catalysed polysaccharide degradation involved the synergistic action of endo-, exo-and processive glycoside hydrolases working in concert to hydrolyse the substrate. More recently this model has been succeeded by one featuring a newly discovered class of mononuclear copper enzymes: lytic polysaccharide monooxygenases (LPMOs; classified as Auxiliary Activity (AA) enzymes in the CAZy classification). In 2013, the structure of an LPMO from Bacillus amyloliquefaciens, BaAA10, was solved with the Cu centre photoreduced to Cu(I) in the X-ray beam. Here we present the catalytic activity of BaAA10. We show that it is a chitin-active LPMO, active on both α and β chitin, with the Cu(II) binding with low nM KD, and the substrate greatly increasing the thermal stability of the enzyme. A spiral data collection strategy has been used to facilitate access to the previously unobservable Cu(II) state of the active centre, revealing a coordination geometry around the copper which is distorted from axial symmetry, consistent with the previous findings from EPR spectroscopy

Culture Of The Australian Red-Claw Crayfish (Cherax Quadricarinatus) In Israel Crayfish Incorporation Into Intensive Tilapia Production Units

This study tested the suitability of the Australian red-claw crayfish Cherax quadricarinatus for rear- ing in an intensive culture system as a supplement to Oreochromis niloticus. Fish were grown in twelve 5.5 m3 tanks at high density (33/m3) for 133 days, alone or with crayfish at two stocking den- sities (10/m2 and 20/m2) with added shelters or with crayfish at the lower density (10/m2) without shelters. Tilapia survival ranged 90.3-95.0% with no significant differences among treatments. The growth rate of the tilapia raised with crayfish (2.05 g/day) was significantly higher than that of tilapia grown alone (1.88 g/day) probably because the fish were feeding on part of the crayfish pellets. Among treatments, there were no significant differences in fish yield. Crayfish survival was extremely low in the ‘no shelter’ treatment (2.9±2.7%) but reasonable (approximately 60%) when raised with shelters. The growth rate of the crayfish raised with shelters was significantly higher at the lower density (0.21 g/day) than at the higher density (0.18 g/day). Further research is needed on rearing tilapia and crayfish to market size in intensive systems, to establish the economic prof- itability of this culture strategy

Should contralateral exploratory thoracotomy be advocated for children with osteosarcoma and early unilateral pulmonary metastases?

Purpose: Children presenting with osteosarcoma and pulmonary metastases have poor survival rates. The standard approach to treating unilateral metastases is ipsilateral thoracotomy with complete resection of the metastases whenever possible. We analyzed whether contralateral exploratory thoracotomy is beneficial in these patients. Methods: We reviewed the records of all osteosarcoma patients presenting with or developing early pulmonary metastases (within 24 months of diagnosis) at the St Jude Children\u27s Research Hospital (Memphis, Tenn) between June 1980 and September 2005. Demographics, imaging results, treatment protocols, surgical procedures, and recurrence, survival, and timeline data were assessed. Results: Of the 109 patients, initial pulmonary involvement was radiographically identified as unilateral in 81 (74%) and bilateral in 28 (26%) patients. Of the patients presenting with unilateral pulmonary metastases, 2 years later, 13 (16%) had recurrence in the ipsilateral and 19 (23%) in the contralateral lung. In 2 (2.4%) patients, metastases recurred bilaterally. There was no evidence of statistically significant difference between the incidence of recurrence in the ipsilateral and contralateral lung (P = .18). Conclusions: Children with osteosarcoma and unilateral pulmonary metastases had similar incidence of recurrence in the ipsilateral and contralateral lung. Their survival rates were also not significantly different. Therefore, contralateral exploratory thoracotomy in patients presenting with unilateral pulmonary metastases will probably not improve survival. © 2009 Elsevier Inc. All rights reserved

Twelve-month observational study of children with cancer in 41 countries during the COVID-19 pandemic

Childhood cancer is a leading cause of death. It is unclear whether the COVID-19 pandemic has impacted childhood cancer mortality. In this study, we aimed to establish all-cause mortality rates for childhood cancers during the COVID-19 pandemic and determine the factors associated with mortality