Multi-omics view of recombinant Yarrowia lipolytica: Enhanced ketogenic amino acid catabolism increases polyketide-synthase-driven docosahexaenoic production to high selectivity at the gram scale

DHA is a marine PUFA of commercial value, given its multiple health benefits. The worldwide emerging shortage in DHA supply has increased interest in microbial cell factories that can provide the compound de novo. In this regard, the present work aimed to improve DHA production in the oleaginous yeast strain Y. lipolytica Af4, which synthetized the PUFA via a heterologous myxobacterial polyketide synthase (PKS)-like gene cluster. As starting point, we used transcriptomics, metabolomics, and 13C-based metabolic pathway profiling to study the cellular dynamics of Y. lipolytica Af4. The shift from the growth to the stationary DHA-production phase was associated with fundamental changes in carbon core metabolism, including a strong upregulation of the PUFA gene cluster, as well as an increase in citrate and fatty acid degradation. At the same time, the intracellular levels of the two DHA precursors acetyl-CoA and malonyl-CoA dropped by up to 98% into the picomolar range. Interestingly, the degradation pathways for the ketogenic amino acids L-lysine, L-leucine, and L-isoleucine were transcriptionally activated, presumably to provide extra acetyl-CoA. Supplementation with small amounts of these amino acids at the beginning of the DHA production phase beneficially increased the intracellular CoA-ester pools and boosted the DHA titer by almost 40%. Isotopic 13C-tracer studies revealed that the supplements were efficiently directed toward intracellular CoA-esters and DHA. Hereby, L-lysine was found to be most efficient, as it enabled long-term activation, due to storage within the vacuole and continuous breakdown. The novel strategy enabled DHA production in Y. lipolytica at the gram scale for the first time. DHA was produced at a high selectivity (27% of total fatty acids) and free of the structurally similar PUFA DPA, which facilitates purification for high-value medical applications that require API-grade DHA. The assembled multi-omics picture of the central metabolism of Y. lipolytica provides valuable insights into this important yeast. Beyond our work, the enhanced catabolism of ketogenic amino acids seems promising for the overproduction of other compounds in Y. lipolytica, whose synthesis is limited by the availability of CoA ester precursors

Pazopanib with 5‐FU and oxaliplatin as first line therapy in advanced gastric cancer: A randomized phase‐II study—The PaFLO trial. A study of the Arbeitsgemeinschaft Internistische Onkologie AIO‐STO‐0510

VEGF inhibition in gastric cancer has a proven benefit in the second line setting. Pazopanib, an oral tyrosine kinase inhibitor, selectively inhibits VEGFR-1, -2 and -3, c-kit and PDGF-R resulting in inhibition of angiogenesis. This open-label randomized phase II trial (2:1) investigated the efficacy of combining pazopanib with FLO (5-fluorouracil, oxaliplatin) vs FLO alone (internal control arm) as first-line treatment in patients with advanced adenocarcinoma of the stomach and gastroesophageal junction (GEJ). Eighty-seven patients were randomized and 78 patients were eligible and evaluable (PaFLO arm 51 patients, FLO arm 27 patients). The PFS rate at 6 months (primary endpoint) was 34% in the PaFLO arm vs 30% in the FLO arm. Comparing PaFLO with FLO median PFS was 4.66 months (95% confidence interval [CI] 2.87-6.46) vs 4.47 months (95% CI 1.79-7.14) (95% CI, hazard ratio [HR] 0.96 (0.60-1.55), P = .882 [exploratory]); median OS was 10.19 months (95% CI 5.46-14.92) vs 7.33 months (95% CI 4.93-9.73), (95% CI HR 1.01 [0.62-1.65], P = .953, exploratory), disease control rate was 72% vs 59%. PaFLO was well tolerable, toxicities were slightly higher in the PaFLO arm. Major adverse events were loss of appetite, nausea, fatigue, diarrhea, neutropenia and thrombocytopenia. Adding pazopanib to chemotherapy shows signs of efficacy but no major improvement in this randomized phase 2 trial. The PFS at 6 months in both arms was lower than expected from the literature. Biomarkers identifying subgroups who benefit and novel combinations are needed. ClinicalTrials.gov: NCT01503372

Photocatalytic Oxidation of NO over Composites of Titanium Dioxide and Zeolite ZSM-5

Composites of TiO2 (Hombikat, P25, sol-gel synthesis) and zeolite ZSM-5 (nSi/nAl = 55) with mass fractions from 25/75 to 75/25 were prepared by mechanical mixing, solid-state dispersion and sol-gel synthesis. Characterization of the composites by X-ray diffraction (XRD), N2-sorption, scanning electron microscopy (SEM), and UV-Vis spectroscopy show that mechanical mixing and solid-state dispersion lead to comparable textural properties of the composites. A homogeneous distribution and intimate contact of small TiO2 particles on the crystal surface of zeolite ZSM-5 were achieved by sol-gel synthesis. The composites were studied in the photocatalytic oxidation (PCO) of NO in a flatbed reactor under continuous flow according to ISO 22197-1. The highest NO conversion of 41% at an NO2 selectivity as low as 19% stable for 24 h on-stream was reached over the TiO2/ZSM-5 composite from sol-gel synthesis with equal amounts of the two components after calcination at 523 K. The higher activity and stability for complete NO oxidation than for pure TiO2 from sol-gel synthesis, Hombikat, or P25 is attributed to the adsorptive properties of the zeolite ZSM-5 in the composite catalyst. Increasing the calcination temperature up to 823 K leads to larger TiO2 particles and a lower photocatalytic activity

The Mechanism of Pseudomorphic Transformation of Spherical Silica Gel into MCM-41 Studied by PFG NMR Diffusometry

The pseudomorphic transformation of spherical silica gel (LiChrospher® Si 60) into MCM-41 was achieved by treatment at 383 K for 24 h with an aqueous solution of cetyltrimethylammonium hydroxide (CTAOH) instead of hexadecyltrimethylammonium bromide (CTABr) and NaOH. The degree of transformation was varied via the ratio of CTAOH solution to initial silica gel rather than synthesis duration. The transformed samples were characterized by N2 sorption at 77 K, mercury intrusion porosimetry, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thus, MCM-41 spheres with diameters of ca. 12 μm, surface areas >1000 m2 g−1, pore volumes >1 cm3 g−1 and a sharp pore width distribution, adjustable between 3.2 and 4.5 nm, were obtained. A thorough pulsed field gradient nuclear magnetic resonance (PFG NMR) study shows that the diffusivity of n-heptane confined in the pores of the solids passes through a minimum with progressing transformation. The final product of pseudomorphic transformation to MCM-41 does not exhibit improved transport properties compared to the initial silica gel. Moreover, the PFG NMR results support that the transformation occurs via formation and subsequent growth of domains of <1 μm containing MCM-41 homogeneously distributed over the volume of the silica spheres

Low-Cost Microwave-Assisted Partial Pseudomorphic Transformation of Biogenic Silica

This work introduces a cost and time efficient procedure to specifically increase mesopore volume and specific surface area of biogenic silica (specific surface area: 147 m2 g −1 and mesopore volume: 0.23 cm3 g −1 ) to make it suitable for applications in adsorption or as catalyst support. The target values were a specific surface area of ∼500 m2 g −1 and a mesopore volume of ∼0.40–0.50 cm3 g −1 as these values are industrially relevant and are reached by potential concurring products such as precipitated silica, silica gel, and fumed silica. The applied process of partial pseudomorphic transformation was carried out as a single reaction step in a microwave reactor instead of commonly used convective heating. In addition, the conventionally used surfactant cetyltrimethylammonium bromide (CTABr) was substituted by the low-cost surfactant (Arquad® 16-29, cetyltrimethylammonium chloride (CTACl) aqueous solution). The influence of microwave heating, type of surfactant as well as the concentration of NaOH and CTACl on the textural and structural properties of the modified biogenic silica was investigated using nitrogen adsorption as well as scanning and transmission electron microscopy. The results show that the textural parameters of the modified biogenic silica can be exactly controlled by the amount of NaOH in the reaction solution. By variation of the NaOH concentration, specific surface areas in the range of 215–1,001 m2 g −1 and mesopore volumes of 0.25–0.56 cm3 g −1 were achieved after reaction at 393 K for 10 min. The presented microwave route using the low-cost surfactant solution decreases the reaction time by 99% and as shown in an example for German prices, lowers the costs for the surfactant by 76–99%

Treatment of refractory germ-cell tumours with single-agent cabazitaxel: a German Testicular Cancer Study Group case series

PURPOSE: Outcomes of multiply relapsed, refractory germ-cell tumour (GCT) patients remain poor with an overall survival (OS) of a few months only. Thus, new therapeutic advances are urgently needed. Cabazitaxel has shown preclinical activity in platinum-resistant GCT models. Here, we report the first clinical case series of cabazitaxel treatment for platinum-refractory GCT. METHODS: Data of multiply relapsed GCT patients receiving single-agent cabazitaxel were retrospectively analysed. Endpoints included 12-week progression-free survival (PFS) rate, disease control rate, tumour marker responses, median PFS and OS, and toxicity. RESULTS: Cabazitaxel showed limited activity in 13 heavily pre-treated GCT patients. After a median follow-up of 23 weeks (IQR 29), 69% of patients were deceased. A median of 2 cycles of cabazitaxel (range 1-7) were applied. The 12-week PFS rate was 31%. Median PFS and OS were 7 and 23 weeks, respectively. Two patients achieved objective responses (15%), three patients (23%) achieved a tumour marker decline ≥ 50%, and the disease control rate was 39%. Cabazitaxel was well tolerated. CTCAE° III-IV haemato-toxicity was most common (54%), and dose reductions were scarce (15%). CONCLUSION: In this case series, cabazitaxel showed limited activity in heavily pre-treated GCT patients. Two-phase II studies are underway (NCT02115165, NCT02478502) prospectively assessing cabazitaxel in multiply relapsed GCTs

The Emergent European Model in Skill Formation: Comparing Higher Education and Vocational Training in the Bologna and Copenhagen Processes

Proposing an alternative to the American model, intergovernmental reform initiatives in Europe have developed and promote a comprehensive European model of skill formation. What ideals, standards, and governance are proposed in this new pan-European model? This model responds to heightened global competition among “knowledge societies” as it challenges national systems to improve. The authors thus compare this emergent European model with the historically influential models of Germany, France, Great Britain, and the United States. To what extent does the European model resemble these traditionally influential national models? The authors report findings of a theory-guided content analysis of official European policy documents in higher education and vocational training from 1998 to 2010. They find that while the European model is a bricolage that integrates diverse characteristics of influential models, the ambitious goals and standards codified in the twin Bologna and Copenhagen processes in higher education and vocational training offer a new model to compete internationally. Dozens of countries now seek to implement these principles. This comparative analysis finds different visions for the future of skill formation on both sides of the Atlantic