Estuarine fish passes in the northern Netherlands provide contrasting windows of opportunity for migrating fish species

The Wadden Sea in north-western Europe is the largest system of connected intertidal sand and mud flats in the world and is included in the UNESCO World Heritage list. Notwithstanding its ecological value, almost all rivers flowing towards the Wadden Sea are heavily modified with inter-tidal barriers, hampering the migration of diadromous fishes. To mitigate the negative effects of such barriers, fish passes were constructed, but their effectiveness is poorly understood. Since most fish passes are only functional during part of the tidal cycle, migration activity should match this operation window to secure effective migration. In this study we focused on the upstream-migrating behaviour of glass eel (the juvenile stage of catadromous eel, Anguilla anguilla) and three-spined stickleback (anadromous Gasterosteus aculeatus) at nine fish passes along the Dutch Wadden Sea coast. We investigated the presence of sticklebacks and glass eel at the downstream side of intertidal barriers in relation to fluctuations in their environment. Fish were collected with 1x1-m lift nets, with a 2-mm mesh size. In 168 sample days between February and May 2014, 4558 samples were taken and a total of 107,349 sticklebacks and 23,082 glass eel were caught. At all locations, glass eel were most abundant in the hour before high tide, while sticklebacks did not show a significant pattern with environmental variables at all locations, but when they did catches were highest at the start of flood tide. This means that the window of opportunity for migration is different for both fish species and that optimisation of the operation window of a fish pass for glass eel could mean a mismatch for stickleback and vice versa. Knowledge of temporal migration dynamics of fish species is therefore essential for the design of effective fish passes

The evolution of precision oncology:The ongoing impact of the Drug Rediscovery Protocol (DRUP)

Background and purpose: The Drug Rediscovery Protocol (DRUP) is a Dutch, pan-cancer, nonrandomized clinical trial that aims to investigate the efficacy and safety of targeted and immunotherapies outside their registered indication in patients with advanced or metastatic cancer. Patients: Patients with advanced or metastatic cancer are eligible when there are no standard of care treatment options left and the tumor possesses a molecular genomic variant for which commercially available anticancer treatment is accessible off-label in DRUP. Clinical benefit is the study’s primary endpoint, characterized by a confirmed objective response or stable disease after at least 16 weeks of treatment. Results: More than 2,500 patients have undergone evaluation, of which over 1,500 have started treatment in DRUP. The overall clinical benefit rate (CBR) remains 33%. The nivolumab cohort for patients with microsatellite instable metastatic tumors proved highly successful with a CBR of 63%, while palbociclib or ribociclib in patients with tumors harboring CDK4/6 pathway alterations showed limited efficacy, with a CBR of 15%. The formation of two European initiatives (PCM4EU and PRIME-ROSE) strives to accelerate implementation and enhance data collection to broaden equitable access to anticancer treatments and gather more evidence. Conclusion: DRUP persists in improving patients access to off-label targeted or immunotherapy in the Netherlands and beyond. The expansion of DRUP-like clinical trials across Europe provides countless opportunities for broadening the horizon of precision oncology.</p

RSPO3 expands intestinal stem cell and niche compartments and drives tumorigenesis

Objective The gross majority of colorectal cancer cases results from aberrant Wnt/ß-catenin signalling through adenomatous polyposis coli (APC) or CTNNB1 mutations. However, a subset of human colon tumours harbour, mutually exclusive with APC and CTNNB1 mutations, gene fusions in RSPO2 or RSPO3, leading to enhanced expression of these R-spondin genes. This suggested that RSPO activation can substitute for the most common mutations as an alternative driver for intestinal cancer. Involvement of RSPO3 in tumour growth was recently shown in RSPO3-fusion-positive xenograft models. The current study determines the extent into which solely a gain in RSPO3 actually functions as a driver of intestinal cancer in a direct, causal fashion, and addresses the in vivo activities of RSPO3 in parallel. Design We generated a conditional Rspo3 transgenic mouse model in which the Rspo3 transgene is expressed upon Cre activity. Cre is provided by cross-breeding with Lgr5-GFP-CreERT2 mice. Results Upon in vivo Rspo3 expression, mice rapidly developed extensive hyperplastic, adenomatous and adenocarcinomatous lesions throughout the intestine. RSPO3 induced the expansion of Lgr5+ stem cells, Paneth cells, non-Paneth cell label-retaining cells and Lgr4+ cells, thus promoting both intestinal stem cell and niche compartments. Wnt/ß-catenin signalling was modestly increased upon Rspo3 expression and mutant Kras synergised with Rspo3 in hyperplastic growth. Conclusions We provide in vivo evidence that RSPO3 stimulates the crypt stem cell and niche compartments and drives rapid intestinal tumorigenesis. This establishes RSPO3 as a potent driver of intestinal cancer and proposes RSPO3 as a candidate target for therapy in patients with colorectal cancer harbouring RSPO3 fusions

Protein dynamics influence the enzymatic activity of phospholipase a/acyltransferases 3 and 4

Phospholipase A/acyltransferase 3 (PLAAT3) and PLAAT4 are enzymes involved in the synthesis of bioactive lipids. Despite sequential and structural similarities, the two enzymes differ in activity and specificity. The relation between the activity and dynamics of the N-terminal domains of PLAAT3 and PLAAT4 was studied. PLAAT3 has a much higher melting temperature and exhibits less nanosecond and millisecond dynamics in the active site, in particular in loop L2(B6), as shown by NMR spectroscopy and molecular dynamics calculations. Swapping the L2(B6) loops between the two PLAAT enzymes results in strongly increased phospholipase activity in PLAAT3 but no reduction in PLAAT4 activity, indicating that this loop contributes to the low activity of PLAAT3. The results show that, despite structural similarity, protein dynamics differ substantially between the PLAAT variants, which can help to explain the activity and specificity differences.Macromolecular BiochemistryMolecular Physiolog

Two β-lactamase variants with reduced clavulanic acid inhibition display different millisecond dynamics

Macromolecular Biochemistr

Phosphate Promotes the Recovery of Mycobacterium tuberculosis beta-Lactamase from Clavulanic Acid Inhibition

Macromolecular Biochemistr

Monitoring phenylalanine concentrations in the follow-up of phenylketonuria patients:An inventory of pre-analytical and analytical variation

Background: Reliable measurement of phenylalanine (Phe) is a prerequisite for adequate follow-up of phenylketonuria (PKU) patients. However, previous studies have raised concerns on the intercomparability of plasma and dried blood spot (DBS) Phe results. In this study, we made an inventory of differences in (pre-)analytical methodology used for Phe determination across Dutch laboratories, and compared DBS and plasma results. Methods: Through an online questionnaire, we assessed (pre-)analytical Phe measurement procedures of seven Dutch metabolic laboratories. To investigate the difference between plasma and DBS Phe, participating laboratories received simultaneously collected plasma-DBS sets from 23 PKU patients. In parallel, 40 sample sets of DBS spotted from either venous blood or capillary fingerprick were analyzed. Results: Our data show that there is no consistency on standard operating procedures for Phe measurement. The association of DBS to plasma Phe concentration exhibits substantial inter-laboratory variation, ranging from a mean difference of −15.5% to +30.6% between plasma and DBS Phe concentrations. In addition, we found a mean difference of +5.8% in Phe concentration between capillary DBS and DBS prepared from venous blood. Conclusions: The results of our study point to substantial (pre-)analytical variation in Phe measurements, implicating that bloodspot Phe results should be interpreted with caution, especially when no correction factor is applied. To minimize variation, we advocate pre-analytical standardization and analytical harmonization of Phe measurements, including consensus on application of a correction factor to adjust DBS Phe to plasma concentrations