Assessing the risk of booster biocides for the marine environment: A case study at the Belgian part of the North Sea.

The biofouling of submerged surfaces such as ship hulls is often prevented by using anti-fouling components in combination with booster biocides. These booster biocides enter the water column and may affect non-target organisms. Although different negative effects have been associated with the use of booster biocides, their effects on non-target organisms are often unknown. So far, the environmental risks for booster biocides have barely been quantified in the North Sea. In this work, the concentration of five commonly used booster biocides as well as tributyltin has been monitored at five dredged spoil disposal sites in the Belgian part of the North Sea and the harbour and ports of Nieuwpoort, Oostende, and Zeebrugge. Hotspots were discovered where the concentration of one or more booster biocides exceeded the predicted no-effect concentration. Tributyltin has been banned since 2008, but concentrations of 237- to 546-fold of the predicted no-effect concentration were detected in the harbours and ports. Moreover, TBT has been detected in the same order of magnitude in other sea basins, emphasizing the need to monitor the trends and impact of booster biocides and TBT in environmental monitoring programs.

Oracle selection provides insight into how far off practice is from Utopia in plant breeding.

Since the introduction of genomic selection in plant breeding, high genetic gains have been realized in different plant breeding programs. Various methods based on genomic estimated breeding values (GEBVs) for selecting parental lines that maximize the genetic gain as well as methods for improving the predictive performance of genomic selection have been proposed. Unfortunately, it remains difficult to measure to what extent these methods really maximize long-term genetic values. In this study, we propose oracle selection, a hypothetical frame of mind that uses the ground truth to optimally select parents or optimize the training population in order to maximize the genetic gain in each breeding cycle. Clearly, oracle selection cannot be applied in a true breeding program, but allows for the assessment of existing parental selection and training population update methods and the evaluation of how far these methods are from the optimal utopian solution.

Emerging pharmaceutical therapies of Ascidian-derived natural products and derivatives.

In a growing multidrug-resistant environment, the identification of potential new drug candidates with an acceptable safety profile is a substantial crux in pharmaceutical discovery. This review discusses several aspects and properties of approved marine natural products derived from ascidian sources (phylum Chordata, subphylum Tunicata) and/or their deduced analogues including their biosynthetic origin, (bio)chemical preclinical assessments and known efficacy-safety profiles, clinical status in trials, but also translational developments, opportunities and final conclusions. The review also describes the preclinical assessments of a large number of other ascidian compounds that have not been involved in clinical trials yet. Finally, the emerging research on the connectivity of the ascidian hosts and their independent or obligate symbiotic guests is discussed. The review covers the latest information on the topic of ascidian-derived marine natural products over the last two decades including 2022, with the majority of publications published in the last decade.

Short- and long-term assessment of PAH, PCB, and metal contamination in the Belgian part of the North Sea.

Dredging activities can result in the relocation of contaminants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and metals from shipping channels, harbours, and ports into the marine environment where these components may exert a negative effect on the marine ecosystem. In this work, contamination associated with dredging is evaluated at and around dredged spoil disposal sites in the Belgian part of the North Sea, taking into account spatial as well as temporal variation. A homogeneous dispersion of the different contaminants was observed at the different sites. However, the contamination pattern was different for disposal sites that were linked with commercial ports, resulting in significantly higher PAH and PCB concentrations. When comparing concentrations with environmental assessment criteria, contamination of PAHs does not exceed these criteria in the Belgian Part of the North Sea, and for PCBs, only CB118 reveals a concerningly high concentration that exceeds the environmental assessment criteria. This is in contrast with metals where the contamination of As, Cr, Ni, and Zn exceeded the environmental limit values both at dredged spoil disposal sites and reference locations.

Deep scoping: a breeding strategy to preserve, reintroduce and exploit genetic variation.

KEY MESSAGE: The deep scoping method incorporates the use of a gene bank together with different population layers to reintroduce genetic variation into the breeding population, thus maximizing the long-term genetic gain without reducing the short-term genetic gain or increasing the total financial cost. Genomic prediction is often combined with truncation selection to identify superior parental individuals that can pass on favorable quantitative trait locus (QTL) alleles to their offspring. However, truncation selection reduces genetic variation within the breeding population, causing a premature convergence to a sub-optimal genetic value. In order to also increase genetic gain in the long term, different methods have been proposed that better preserve genetic variation. However, when the genetic variation of the breeding population has already been reduced as a result of prior intensive selection, even those methods will not be able to avert such premature convergence. Pre-breeding provides a solution for this problem by reintroducing genetic variation into the breeding population. Unfortunately, as pre-breeding often relies on a separate breeding population to increase the genetic value of wild specimens before introducing them in the elite population, it comes with an increased financial cost. In this paper, on the basis of a simulation study, we propose a new method that reintroduces genetic variation in the breeding population on a continuous basis without the need for a separate pre-breeding program or a larger population size. This way, we are able to introduce favorable QTL alleles into an elite population and maximize the genetic gain in the short as well as in the long term without increasing the financial cost.

Preservation of Genetic Variation in a Breeding Population for Long-Term Genetic Gain.

Genomic selection has been successfully implemented in plant and animal breeding. The transition of parental selection based on phenotypic characteristics to genomic selection (GS) has reduced breeding time and cost while accelerating the rate of genetic progression. Although breeding methods have been adapted to include genomic selection, parental selection often involves truncation selection, selecting the individuals with the highest genomic estimated breeding values (GEBVs) in the hope that favorable properties will be passed to their offspring. This ensures genetic progression and delivers offspring with high genetic values. However, several favorable quantitative trait loci (QTL) alleles risk being eliminated from the breeding population during breeding. We show that this could reduce the mean genetic value that the breeding population could reach in the long term with up to 40%. In this paper, by means of a simulation study, we propose a new method for parental mating that is able to preserve the genetic variation in the breeding population, preventing premature convergence of the genetic values to a local optimum, thus maximizing the genetic values in the long term. We do not only prevent the fixation of several unfavorable QTL alleles, but also demonstrate that the genetic values can be increased by up to 15 percentage points compared with truncation selection.