Signals of predation-induced directional and disruptive selection in the threespine stickleback

Background: Different predation regimes may exert divergent selection pressure on phenotypes and their associated genotypes. Threespine stickleback Gasterosteus aculeatus have a suite of bony structures, which have been shown to be an effective defence against predation and have a well-known genetic basis. Question: Do different predator regimes induce different selective pressures on growth rates and defence phenotypes in threespine stickleback between different habitats across distinct age classes? Hypothesis: In the presence of predation-induced selection, we expect diverging morphological responses between populations experiencing either low or high predation pressure. Study system: Threespine stickleback were sampled from two natural but recently established populations in an invasive range. One site has a high density of fish and insect predators, while at the other site predation pressure is low. Methods: We inferred predator-induced selection on defence traits by comparing the distribution of size classes, defence phenotypes, and an armour-related genotype between different age classes in a high and a low predation regime. Results: Under high predation, there are indications of directional selection for faster growth, whereas lateral plate phenotypes and associated genotypes show indications for disruptive selection. Heterozygotes at the Eda-gene have a lower survival rate than either homozygote. Neither pattern is evident in the low predation regime. Conclusion: Potential evolutionary responses to divergent predation pressures between sites are apparent in a recently established system

Hotshots, hot spots, and female preference: exploring lek formation models with a bower-building cichlid fish

In many animals, males congregate in leks that females visit for the sole purpose of mating. We observed male and female behavior on 3 different-sized leks of the bower-building cichlid fish Nyassachromis cf. microcephalus to test predictions of 3 prominent lek models: the "hotshot,” "hot spot,” and "female preference” models. In this system, we were able to refine these predictions by distinguishing between indirect mate choice, by which females restrict their set of potential mates in the absence of individual male assessment, and direct mate choice, by which females assess males and their territories through dyadic behavioral interactions. On no lek were males holding central territories favored by indirect or direct mate choice, contrary to the prediction of the hotshot model that leks form because inferior males establish territories surrounding hotshot males preferred by females. Average female encounter rate of males increased with lek size, a pattern typically interpreted as evidence that leks form through female preference for lekking males, rather than because males congregate in hot spots of high female density. Female propensity to engage in premating behavior once courted did not increase with lek size, suggesting female preference for males on larger leks operated through indirect choice rather than direct choice based on individual assessment. The frequency of male-male competitive interactions increased with lek size, whereas their foraging rate decreased, implying a cost to males maintaining territories on larger leks. Together these data most strongly support the female preference model, where females may benefit through indirect mate choice for males able to meet the competitive cost of occupying larger lek

When Phenotypes Do Not Match Genotypes - Unexpected Phenotypic Diversity and Potential Environmental Constraints in Icelandic Stickleback

Divergent lateral plate phenotypes in stickleback represent one of only a few cases known where a single gene underlies the phenotype under divergent selection between different habitats. However, the selection pressures leading to the repeated loss of lateral plates in freshwater are still not well understood. By genotyping 838 individuals from nine independently colonized lakes and one marine population in Iceland, we found i) that only in some lakes are phenotypes associated with the expected genotype and ii) that the independent repeated occurrence of a rarely described plate phenotype is expressed in the absence of an allele that is usually associated with this phenotype. This suggests that either other genes such as modifiers might be under divergent selection between lakes or that lateral plate expression in these populations is restricted due to environmental constraints

Murine glial progenitor cells transplantation and synthetic PreImplantation Factor (sPIF) reduces inflammation and early motor impairment in ALS mice.

Amyotrophic lateral sclerosis (ALS) is a progressive motor neuronal disorder characterized by neuronal degeneration and currently no effective cure is available to stop or delay the disease from progression. Transplantation of murine glial-restricted precursors (mGRPs) is an attractive strategy to modulate ALS development and advancements such as the use of immune modulators could potentially extend graft survival and function. Using a well-established ALS transgenic mouse model (SOD1G93A), we tested mGRPs in combination with the immune modulators synthetic PreImplantation Factor (sPIF), Tacrolimus (Tac), and Costimulatory Blockade (CB). We report that transplantation of mGRPs into the cisterna magna did not result in increased mice survival. The addition of immunomodulatory regimes again did not increase mice lifespan but improved motor functions and sPIF was superior compared to other immune modulators. Immune modulators did not affect mGRPs engraftment significantly but reduced pro-inflammatory cytokine production. Finally, sPIF and CB reduced the number of microglial cells and prevented neuronal number loss. Given the safety profile and a neuroprotective potential of sPIF, we envision its clinical application in near future

Overview of Evidence of Antimicrobial Use and Antimicrobial Resistance in the Food Chain

Antimicrobial resistance (AMR) is a global health problem. Bacteria carrying resistance genes can be transmitted between humans, animals and the environment. There are concerns that the widespread use of antimicrobials in the food chain constitutes an important source of AMR in humans, but the extent of this transmission is not well understood. The aim of this review is to examine published evidence on the links between antimicrobial use (AMU) in the food chain and AMR in people and animals. The evidence showed a link between AMU in animals and the occurrence of resistance in these animals. However, evidence of the benefits of a reduction in AMU in animals on the prevalence of resistant bacteria in humans is scarce. The presence of resistant bacteria is documented in the human food supply chain, which presents a potential exposure route and risk to public health. Microbial genome sequencing has enabled the establishment of some links between the presence of resistant bacteria in humans and animals but, for some antimicrobials, no link could be established. Research and monitoring of AMU and AMR in an integrated manner is essential for a better understanding of the biology and the dynamics of antimicrobial resistance

Status Report on Education in the Economics of Animal Health: Results from a European Survey

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Neuropixels 2.0: A miniaturized high-density probe for stable, long-term brain recordings

Measuring the dynamics of neural processing across time scales requires following the spiking of thousands of individual neurons over milliseconds and months. To address this need, we introduce the Neuropixels 2.0 probe together with newly designed analysis algorithms. The probe has more than 5000 sites and is miniaturized to facilitate chronic implants in small mammals and recording during unrestrained behavior. High-quality recordings over long time scales were reliably obtained in mice and rats in six laboratories. Improved site density and arrangement combined with newly created data processing methods enable automatic post hoc correction for brain movements, allowing recording from the same neurons for more than 2 months. These probes and algorithms enable stable recordings from thousands of sites during free behavior, even in small animals such as mice