Habitat utilization and feeding ecology of small round goby in a shallow brackish lagoon

We examined small-scale distribution and feeding ecology of a non-native fish species, round goby (Neogobius melanostomus (Pallas, 1814)), in different habitats of a coastal lagoon situated in the south-western Baltic Sea. First observations of round goby in this lagoon were reported in 2011, 3 years before the current study was conducted, and information on this species’ basic ecology in different habitats is limited. We found that mainly juvenile round gobies are non-randomly distributed between habitats and that abundances potentially correlate positively with vegetation density and thus structural complexity of the environment. Abundances were highest in shallower, more densely vegetated habitats indicating that these areas might act as a refuge for small round gobies by possibly offering decreased predation risk and better feeding resources. Round goby diet composition was distinct for several length classes suggesting an ontogenetic diet shift concerning crustacean prey taxa between small (≤ 50 mm total length, feeding mainly on zooplankton) and medium individuals (51–100 mm, feeding mainly on benthic crustaceans) and another diet shift of increasing molluscivory with increasing body size across all length classes. Differences in round goby diet between habitats within the smallest length class might potentially be related to prey availability in the environment, which would point to an opportunistic feeding strategy. Here, we offer new insights into the basic ecology of round goby in littoral habitats, providing a better understanding of the ecological role of this invasive species in its non-native range, which might help to assess potential consequences for native fauna and ecosystems

Predator and prey: the role of the round goby Neogobius melanostomus in the western Baltic

Different studies on the position of the non-indigenous species Neogobius melanostomus within the coastal food web of the Pomeranian Bay (western Baltic) were performed, resulting in a quantitative and qualitative species list of prey organisms found in the stomachs of the invader and an estimation concerning the importance of round goby as prey for different resident predators. It seems that the colonization process is not fully completed yet, but the results reveal that the species is already established in the food web 16 years after the first observation within the study area. The results show that N. melanostomus feed upon a wide range of different resident organisms. While a direct predation effect on native fish species appears rather unlikely, indirect effects such as competition cannot yet be excluded. In addition, our results reveal an ontogenetic diet shift and that the round goby itself already serves as an important prey for piscivorous fish and seabirds. Finally, we formulate different hypotheses based on our results which will require further research

Coastal Habitats and their Importance for the Biodiversity of Faunal Communities

Coastal habitats represent highly productive areas serving important functions for multiple organism groups. These shallow areas generally maintain high faunal biodiversity, providing important ecosystem goods and services, and are currently threatened by various environmental and anthropogenic stressors, including climate change and eutrophication. Therefore, it is essential to assess the link between coastal habitats and community biodiversity, thereby getting a better understanding of their significance for ecosystem functioning. This thesis explores the importance of coastal habitats for faunal biodiversity and examines how biological interactions contribute to structuring biodiversity among these habitats. The four studies included in this thesis focus on fish and invertebrate communities in the Baltic Sea, and biodiversity is assessed by means of taxonomic and trait-based approaches. Studied habitats comprise rocky reefs, bladderwrack belts, bare sand areas, seagrass meadows and macrophyte beds. Community biodiversity and structure among habitats were explored by field studies, whereas biological interactions within the same organism group were examined through laboratory experiments. Field experiments were conducted to investigate the impact of a nonnative fish species on the diversity of native invertebrate communities. The findings highlight that biodiversity of benthic macroinvertebrate and fish communities is distributed heterogeneously among several coastal habitats, which possess distinct community compositions. The sediments of seagrass meadows had the highest invertebrate diversity, while bare sand areas supported the highest fish diversity from a taxonomic and trait-based point of view. Invertebrate community composition differed between vegetated and non-vegetated habitats and sediments, indicating that habitat complexity plays an important role in structuring communities. The biological trait approach was found to provide essential information on the biodiversity of communities, such as the existence of dominant traits in a habitat, which is why a combination of taxonomic and trait-based approaches in the assessment of biodiversity is suggested. This thesis shows that the observed biodiversity across coastal habitats is influenced by biological interactions between organisms. Predation risk and competition affected the habitat use of a common Baltic Sea fish species, perch, which adapted its habitat use to the presence of a predator and competitor fish species, respectively, by increasingly occupying a habitat that was not used by the other species. This effect was only documented when one of the habitat options comprised a structurally more complex macrophyte habitat, emphasizing the link between structural complexity and interspecific interactions. Non-native round gobies of different size groups possessed a distinct diet composition, and juveniles of this species were most abundant in shallower, densely vegetated habitats, indicating that the impact of this invader on native biodiversity might depend on which round goby size classes are present in a specific environment. Direct predation impacts of round gobies on native invertebrate communities comprised a decline in overall abundance, biomass and species richness, with the most pronounced negative effect on the abundances of common bivalve and gastropod species and their associated trait categories. Thus, round gobies altered both the taxonomic and trait-based diversity of native invertebrates, which might entail repercussions for certain ecosystem functions, such as the magnitude of grazing. The findings of this thesis demonstrate that biological interactions contribute to the structuring of communities across habitats by affecting the habitat use of mobile organisms and by directly modifying community composition and diversity via predator-prey interactions. Biological interactions therefore represent important factors influencing biodiversity across coastal habitats and are thus relevant for ecosystem functioning. This thesis also highlights the significance of structural habitat complexity, which influences community structure and diversity, as well as biological interactions. Finally, the results suggest that biological traits should be incorporated as indicators in the management and conservation of coastal habitats, as they provide important information on the link between coastal habitats, community biodiversity and ecosystem functioning

Breeding of Cav2.3 deficient mice reveals Mendelian inheritance in contrast to complex inheritance in Cav3.2 null mutant breeding

High voltage-activated Cav2.3 R-type Ca2+ channels and low voltage-activated Cav3.2 T-type Ca2+ channels were reported to be involved in numerous physiological and pathophysiological processes. Many of these findings are based on studies in Cav2.3 and Cav3.2 deficient mice. Recently, it has been proposed that inbreeding of Cav2.3 and Cav3.2 deficient mice exhibits significant deviation from Mendelian inheritance and might be an indication for potential prenatal lethality in these lines. In our study, we analyzed 926 offspring from Cav3.2 breedings and 1142 offspring from Cav2.3 breedings. Our results demonstrate that breeding of Cav2.3 deficient mice shows typical Mendelian inheritance and that there is no indication of prenatal lethality. In contrast, Cav3.2 breeding exhibits a complex inheritance pattern. It might be speculated that the differences in inheritance, particularly for Cav2.3 breeding, are related to other factors, such as genetic specificities of the mutant lines, compensatory mechanisms and altered sperm activity

The Ca-V 2.3 R-Type Voltage-Gated Ca2+ Channel in Mouse Sleep Architecture

Study Objectives: Voltage-gated Ca2+ channels (VGCCs) are key elements in mediating thalamocortical rhythmicity. Low-voltage activated (LVA) Ca(V)3 T-type Ca2+ channels have been related to thalamic rebound burst firing and to generation of non-rapid eye movement (NREM) sleep. High-voltage activated (HVA) Ca(V)1 L-type Ca2+ channels, on the opposite, favor the tonic mode of action associated with higher levels of vigilance. However, the role of the HVA Non-L-type Ca(V)2.3 Ca2+ channels, which are predominantly expressed in the reticular thalamic nucleus (RTN), still remains unclear. Recently, Ca(V)2.3(-/-) mice were reported to exhibit altered spike-wave discharge (SWD)/absence seizure susceptibility supported by the observation that Ca(V)2.3 mediated Ca2+ influx into RTN neurons can trigger small-conductance Ca2+-activated K+-channel type 2 (SK2) currents capable of maintaining thalamic burst activity. Based on these studies we investigated the role of Ca(V)2.3 R-type Ca2+ channels in rodent sleep. Methods: The role of Ca(V)2.3 Ca2+ channels was analyzed in Ca(V)2.3(-/-) mice and controls in both spontaneous and artificial urethane-induced sleep, using implantable video-EEG radiotelemetry. Data were analyzed for alterations in sleep architecture using sleep staging software and time-frequency analysis. Results: Ca(V)2.3 deficient mice exhibited reduced wake duration and increased slow-wave sleep (SWS). Whereas mean sleep stage durations remained unchanged, the total number of SWS epochs was increased in Ca(V)2.3(-/-) mice. Additional changes were observed for sleep stage transitions and EEG amplitudes. Furthermore, urethane-induced SWS mimicked spontaneous sleep results obtained from Ca(V)2.3 deficient mice. Quantitative Real-time PCR did not reveal changes in thalamic Ca(V)3 T-type Ca2+ channel expression. The detailed mechanisms of SWS increase in Ca(V)2.3(-/-) mice remain to be determined. Conclusions: Low-voltage activated Ca(V)2.3 R-type Ca2+ channels in the thalamocortical loop and extra-thalamocortical circuitries substantially regulate rodent sleep architecture thus representing a novel potential target for pharmacological treatment of sleep disorders in the future

Coastal habitats and their importance for the diversity of benthic communities: A species- and trait-based approach

Coastal habitats are used by a great variety of organisms during some or all stages of their life cycle. When assessing the link between biological communities and their environment, most studies focus on environmental gradients, whereas the comparison between multiple habitats is rarely considered. Consequently, trait-based aspects of biodiversity in and between habitats have received little attention. Here, we use the biological trait approach in addition to the more common species-based approach to examine trait and taxonomic diversity and composition of invertebrate and fish communities in different coastal habitats, common in the northern Baltic Sea. The habitats include bladderwrack (Fucus), seagrass (Zostera), rock with associated algal species (Rock), and bare sand (Sand). We found distinct differences in community diversity and composition between the habitats. For invertebrates, the sediment of the seagrass meadow had the highest taxonomic and trait richness and diversity, whereas Sand had the highest for fish. The highest dissimilarity in invertebrate community composition was between epifaunal (Rock, Fucus, Zostera Epifauna) and infaunal habitats (Sand, Zostera Infauna) on the one hand, and between vegetated (Zostera Infauna) and unvegetated sediments (Sand) on the other hand, emphasizing the major role vegetation plays in structuring communities. We demonstrate that fish community composition is distinct based on species, and to a lesser degree also distinct based on traits, in the different studied habitats. Both invertebrate and fish communities were more similar on a trait level than taxonomically among the habitats highlighting the presence of similar trait identities in the different habitats. Among the traits examined, Body size contributed most to dissimilarities among habitats for both invertebrates and fish, pointing out the ecological importance of body size for differentiating trait composition of communities. Based on our assessment of biodiversity, using the biological trait approach parallel to the taxonomic approach, we show that trait-based measures clearly provide additional information, such as key functions present in a habitat. This aspect cannot be captured by solely using taxonomic indices, which only shed light on diversity from a species identity point of view. Consequently, to include the ecological role of species, we recommend using biological traits in addition to species-based measures in the assessment of biodiversity, and especially in the management and conservation of coastal habitats, given the important ecosystem goods and services these areas provide

The Janus-like Association between Proton Pump Inhibitors and Dementia

Early pharmacoepidemiological studies suggested that Proton Pump Inhibitors (PPIs) might increase the risk of Alzheimer’s Disease (AD) and non-AD related dementias. These findings were supported by preclinical studies, specifically stressing the proamyloidogenic and indirect anticholinergic effects of PPIs. However, further large-scale pharmacoepidemiological studies showed inconsistent results on the association between PPIs and dementia. Pharmacodynamically, these findings might be related to the LXR/RXR-mediated amyloid clearance effect and anti-inflammatory action of PPIs. Further aspects that influence PPI effects on AD are related to patient- specific pharmacokinetic and pharmacogenomic characteristics. In conclusion, a personalized (individualized) medicinal approach is necessary to model and predict the potential harmful or beneficial effects of PPIs in AD and non-AD-related dementias in the future

Gender specific hippocampal whole genome transcriptome data from mice lacking the Cav2.3 R-type or Cav3.2 T-type voltage-gated calcium channel

Voltage-gated Ca2+ channels are of central relevance in mediating numerous intracellular and transcellular processes including excitation-contraction coupling, excitation secretion-coupling, hormone and neurotransmitter release and gene expression. The Cav2.3 R-type Ca2+ channel is a high-voltage activated channel which plays a crucial role in neurotransmitter release, long-term potentiation and hormone release. Furthermore, Cav2.3 R-type channels were reported to be involved in ictogenesis, epileptogenesis, fear behavior, sleep, pre-and postsynaptic integration and rhythmicity within the hippocampus. Cav3 T-type Ca2+ channels are low-voltage activated and also widely expressed throughout the brain enabling neurons to switch between different firing patterns and to modulate burst activity. Disruption of T-type Ca2+ current has been related to sleep disorders, epilepsy, Parkinson׳s disease, depression, schizophrenia and pain. Cav3.2 ablation was further attributed to elevated anxiety and hippocampal alterations resulting in impaired long-term potentiation and memory. Given the importance of Cav2.3 and Cav3.2 voltage-gated Ca2+ channels within the CNS, particularly the hippocampus, we collected gender specific microarray transcriptome data of murine hippocampal RNA probes using the Affymetrix Exon Expression Chip Mouse Gene 1.0 ST v1. Information presented here includes transcriptome data from Cav2.3+/+, Cav2.3+/−, Cav2.3−/−, Cav3.2+/+, Cav3.2+/− and Cav3.2−/− mice from both genders, the protocol and list of primers used for genotyping animals, the hippocampal RNA isolation procedure and quality controls