Molecular Characterization and SNP Development for the Porcine Il6 and Il10 Genes

Different cytokines are secreted in response to specific microbial molecules referred to as pathogen associated molecular patterns (PAMPs). Interleukin 6 (IL6) and interleukin 10 (IL10), both secreted by macrophages and lymphocytes, play a central role in the immunological response. In this work we obtained the genomic structure and complete DNA sequence of the porcine IL6 and IL10 genes and identified polymorphisms in the genomic sequences of these genes on a panel of ten different pig breeds. Comparative intra- and interbreed sequence analysis revealed a total of eight polymorphisms in the porcine IL6 gene and 21 in the porcine IL10 gene, which include single nucleotide polymorphisms (SNPs) and insertion deletion polymorphisms (indels). Additionally, the chromosomal localization of the IL10 gene was determined by FISH and RH mapping.     

Trophic complexity of small fish in nearshore food webs

Small nearshore fishes are an important part of lacustrine and functional diversity and link pelagic and benthic habitats by serving as prey for larger nearshore and offshore fishes. However, the trophic complexity of these small nearshore fishes is often unrecognized and detailed studies of their role in food webs are lacking. Here, we examined niche space patterns of small nearshore fish species using Bayesian analyses of carbon and nitrogen stable isotope data in nine freshwater lakes that are among the largest lakes in Minnesota. We found considerable variability in niche areas within species and high variability in niche overlap across species. At the assemblage level, niche overlap (average diet overlap of all species pairs at a lake) decreased as whole-lake species richness increased, possibly indicating a greater degree of resource specialization in more speciose lakes. Overall fish niche space was weakly but significantly related to niche space of their invertebrate prey. Although nearshore benthic resources contributed to fish diets in all lakes, all fish species also had non-negligible and variable contributions from pelagic zooplankton. This inter- and intraspecific variability in trophic niche space likely contributes to the multi-level trophic complexity, functional diversity, and potentially food web resilience to ecosystem changes.

     

Cross-reactivity and immunotherapeutic potential of BamA recombinant protein from Acinetobacter baumannii

Acinetobacter baumannii is an important nosocomial pathogen. BamA is a protein that belongs to a complex responsible for organizing the proteins on the bacterial outer membrane. In this work, we aimed to evaluate murine immune responses to BamA recombinant protein (rAbBamA) from A. baumannii in an animal model of infection, and to assess cross-reactivity of this target for the development of anti-A. baumannii vaccines or diagnostics. Immunization of mice with rAbBamA elicited high antibody titers and antibody recognition of native A. baumannii BamA. Immunofluorescence also detected binding to the bacterial surface. After challenge, immunized mice demonstrated a 40% survival increase and better bacterial clearance in kidneys. Immunoblot of anti-rAbBamA against other medically relevant bacteria showed binding to proteins of approximately 35 kDa in Klebsiella pneumoniae and Escherichia coli lysates, primarily identified as OmpA and OmpC, respectively. Altogether, our data show that anti-rAbBamA antibodies provide a protective response against A. baumannii infection in mice. However, the response elicited by immunization with rAbBamA is not completely specific to A. baumannii. Although a broad-spectrum vaccine that protects against various pathogens is an appealing strategy, antibody reactivity against the human microbiota is undesired. In fact, immunization with rAbBamA produced noticeable effects on the gut microbiota. However, the changes elicited were small and non-specific, given that no significant changes in the abundance of Proteobacteria were observed. Overall, rAbBamA is a promising target, but specificity must be considered in the development of immunological tools against A. baumannii.     

River drying influences genetic variation and population structure in an Arctic freshwater fish

Conserving biodiversity in an era of rapid climate change requires understanding the mechanisms that influence dispersal, gene flow and, ultimately, species persistence. This information is becoming critical for conserving key species in rapidly warming places such as the Arctic. Arctic freshwater fish not only face warmer conditions, but also the drying of tundra streams due to climate change. Here, we examined population structure, gene flow, and the influence of landscape features on the neutral genetic variation of the Arctic grayling on Alaska’s North Slope. We estimated the number of genetically distinct clusters and determined effective population sizes for and patterns of gene flow among geographic regions. We predicted that river distance, river drying, distance to the coast, and elevational gradient would influence genetic differentiation for Arctic grayling. Bayesian clustering and discriminant analysis of principal components found support for five or six genetic clusters roughly corresponding to downstream and headwater subwatersheds. Estimates of gene flow revealed asymmetric downstream bias. River distance and river dry zones were significantly associated with increasing genetic differentiation among sampling locations despite this species' high dispersal capability and the temporary nature of dry zones. Isolation and downstream-biased dispersal could contribute to high levels of inter-population genetic variation among the headwaters of the North Slope Arctic grayling metapopulation, which might be particularly important for species conservation during rapid climate change. More generally, small, isolated populations might drive particular alleles to higher frequencies due to selection or drift, thus promoting the genetic potential for rapid evolutionary changes under future climate change.

     

Effectiveness and outcomes of invasive species removal in Hawaiian streams

Despite aquatic invasive species (AIS) being a widely recognized threat to native biodiversity in streams on subtropical and tropical oceanic islands across the Pacific, AIS management has been constrained by concerns that methods of removal could result in more harm than good. In this study, we assessed the effectiveness and outcomes of combining hand-netting and streamside sequestration of native species with AIS removal via three-pass electrofishing tailored for Hawaiian Island watersheds. Removals were conducted in 13 watersheds on the island of O‘ahu following a before-after, control-impact design to assess how AIS removal and post-removal community reassembly varied by surface flow and target species of interest. We found that removals resulted in a sharp reduction in AIS densities without altering native species densities. Removal efficacy was greatest in streams with intermediate mean discharge irrespective of target group or pre-removal AIS densities. Long-term monitoring demonstrated that removals led to persistent shifts in community composition reflecting sustained reductions in AIS densities. These findings indicate that electrofishing can be a valuable tool for AIS management in Hawaiian and other subtropical Pacific island streams, so long as steps are taken to minimize potential harm to at-risk and culturally important native species.

     

Combining population genomics and ecological niche modeling to assess taxon limits between Carex jemtlandica and C. lepidocarpa

Carex section Ceratocystis (Cyperaceae) is a group of recently evolved plant species, in which hybridization is frequent, introgression is documented, taxonomy is complex, and morphological boundaries are vague. Within this section, a unified taxonomic treatment of the Carex jemtlandica–Carex lepidocarpa species complex does not exist, and Norway may currently be the sole country accepting species rank for both. Carex jemtlandica is mainly confined to Fennoscandia and is thus a Fennoscandian conservation responsibility. This motivated us to test the principal hypothesis that both C. jemtlandica and C. lepidocarpa represent evolutionary significant units, and that both deserve their current recognition at species level. We investigated their evolutionary distinctiveness in Norway,using restriction site-associated DNA sequencing and ecological niche modeling. Our genomic results reveal two genetic clusters, largely corresponding to C. jemtlandica and C. lepidocarpa that also remain distinct in sympatry, despite clear indications of ongoing hybridization and introgression. The ecological niche modeling suggests that they occupy different environmental niches. Jointly, our results clearly show that C. jemtlandica and C. lepidocarpa represent separately evolving entities that should qualify recognition as evolutionary significant units. Given the high level of introgression compared to other hybridizing species pairs in Carex we recommend treating C. jemtlandica as a subspecies of C. lepidocarpa.     

Existence of natural mouse IgG mAbs recognising epitopes shared by malondialdehyde acetaldehyde adducts and Porphyromonas gingivalis

Natural Abs are produced by B lymphocytes in the absence of external Ag stimulation. They recognise self, altered self and foreign Ags, comprising an important first-line defence against invading pathogens and serving as innate recognition receptors for tissue homeostasis. Natural IgG Abs have been found in newborns and uninfected individuals. Yet, their physiological role remains unclear. Previously, no natural IgG Abs to oxidation-specific epitopes have been reported. Here, we show the cloning and characterisation of mouse IgG mAbs against malondialdehyde acetaldehyde (MAA)-modified low-density lipoprotein. Sequence analysis reveals high homology with germline genes, suggesting that they are natural. Further investigation shows that the MAA-specific natural IgG Abs cross-react with the major periodontal pathogen Porphyromonas gingivalis and recognise its principle virulence factors gingipain Kgp and long fimbriae. The study provides evidence that natural IgGs may play an important role in innate immune defence and in regulation of tissue homeostasis by recognising and removing invading pathogens and/or modified self-Ags, thus being involved in the development of periodontitis and atherosclerosis.